SUGEN INC
8-K, 1997-09-18
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 8-K
                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934


      Date of Report (Date of earliest event reported): September 12, 1997



                                   SUGEN, INC.
             (Exact name of registrant as specified in its charter)



      Delaware                        0-24814                      13-3629196
(State of jurisdiction)        (Commission File No.)             (IRS Employer
                                                             Identification No.)


                               351 Galveston Drive
                         Redwood City, California 94063
              (Address of principal executive offices and zip code)


       Registrant's telephone number, including area code: (650) 306-7700


<PAGE>


Item 5.  Other Events.

- --------------------------------------------------------------------------------

     On September 10, 1997,  SUGEN,  Inc. (the "Company")  announced the private
     placement of $17,500,000 aggregate principal amount of its 5% Senior Custom
     Convertible  Notes due 2000 (the "Notes").  The private placement closed on
     September 12, 1997 (the "Closing Date").  The following  summary of certain
     terms of the Notes does not  purport to be a  complete  description  of the
     terms of the Notes and is  qualified  in its  entirety by  reference to the
     Note Purchase  Agreement and the form of Note,  which are  incorporated  by
     reference  herein and copies of which are filed as Exhibits  4.1 and 4.2 to
     this Form 8-K.

     The Notes were sold at par,  mature in September  2000 and bear interest at
     the rate of 5% per  annum,  payable  in cash  or,  at the  election  of the
     Company,  shares of common stock of the Company (the "Common Stock") valued
     at the fair market  value of the Common  Stock at the time of the  interest
     payment.

     The Notes, which will not be convertible for 90 days from the Closing Date,
     can thereafter be converted,  together with accrued and unpaid interest and
     subject to certain limitations, into shares of Common Stock at a conversion
     price  equal to the  average of the two lowest  trade  prices of the Common
     Stock as reported on Nasdaq for the 20 trading days  immediately  preceding
     the conversion date (the "Conversion Price").  Starting on January 19, 1998
     (the "Fixed Conversion  Date"), the Conversion Price may not exceed 115% of
     the average  closing bid price of the Common  Stock for the 20 trading days
     immediately  preceding the Fixed  Conversion  Date. An Investor will not be
     permitted at any time to convert in excess of the principal amount of Notes
     which  would  result  in such  Investor  owning  more than 4.9% of the then
     outstanding Common Stock.

     If at any time the number of shares  issuable upon  conversion of the Notes
     exceeds  the number of shares of Common  Stock  available  for  issuance in
     connection  with the Notes without  obtaining the approval of the Company's
     stockholders  in  accordance  with  Nasdaq   requirements,   then,  at  the
     Investors' option, the Company may be required to redeem from the Investors
     in cash (at redemption  prices ranging from 112.5% to 120% depending on the
     date of  redemption)  a  sufficient  principal  amount of Notes so that the
     remaining  Notes are fully  convertible.  The  Company  may also redeem the
     Notes in connection with an acquisition of the Company at redemption prices
     ranging from 125% to 130%. Upon the occurrence and continuation of an event
     of default,  the Company will be required to redeem the Notes at redemption
     prices ranging from 115% to 122.5%.

     If the  Notes  are not  converted  into  Common  Stock,  upon  maturity  in
     September   2000,  the  Notes  will  be  exchanged  for  13.75%   five-year
     debentures.  Pursuant  to the  terms of the  Notes,  in  addition  to other
     covenants,  the Company has agreed to certain limitations on the incurrence
     of additional indebtedness.

                                       1.

<PAGE>


     In connection with the private placement, Investors were granted three-year
     warrants to purchase  up to 262,500  shares of Common  Stock at an exercise
     price of $16.74 per share.

     Diaz & Altschul  Capital,  LLC of New York City was the placement  agent in
     the transaction.  In consideration for its services as placement agent, the
     Company paid Diaz & Altschul  Capital,  LLC a fee of $875,000 and issued to
     an affiliate  of Diaz & Altschul  Capital,  LLC warrants to acquire  70,000
     shares of Common Stock at an exercise price of $16.74 per share.

     The Company has agreed to file a  registration  statement for the resale of
     the Common Stock  issuable upon  conversion  of the Notes,  upon payment of
     interest  with  respect  to the Notes in  shares  of Common  Stock and upon
     exercise of the  warrants,  as the case may be,  within  thirty days of the
     Closing  Date.  The Company will be required to redeem the Notes at 115% if
     it  does  not  file  the  registration  statement  by  such  time or if the
     registration  statement  is not  declared  effective  within 90 days of the
     Closing  Date.  The Company  expects to initially  register up to 2,262,500
     shares of Common Stock.

                                       2.

<PAGE>


Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits.

- --------------------------------------------------------------------------------

(a)      Financial Statements.

         None.

(b)      Pro Forma Financial Information.

         None.

(c)      Exhibits.

 4.1     Form of Note Purchase Agreement,  dated as of September 8, 1997, by and
         between the Company and the investors named therein.

 4.2     Form of 5% Senior Custom Convertible Note due 2000.

 4.3     Form of Common Stock Purchase Warrant.

99.1     Press Release, titled "SUGEN, Inc. Announces Private Placement of $17.5
         Million Senior Convertible Notes," dated September 10, 1997.

                                       3.

<PAGE>


                                   SIGNATURES


     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                                                SUGEN, Inc.


Dated:  September 18, 1997                      By: /s/ Christine E. Gray-Smith
                                                    ----------------------------
                                                       Christine E. Gray-Smith
                                                       Vice President, Finance
                                                      (Principal Financial and
                                                       Accounting Officer)


                                       4.



                             NOTE PURCHASE AGREEMENT


                          DATED AS OF SEPTEMBER 8, 1997


                                 BY AND BETWEEN


                                   SUGEN, INC.


                                       AND


                          DELTA OPPORTUNITY FUND, LTD.





                   5% SENIOR CUSTOM CONVERTIBLE NOTES DUE 2000


<PAGE>





                                PLACEMENT AGENT:

                          DIAZ & ALTSCHUL CAPITAL, LLC





<PAGE>


                                   SUGEN, INC.

                             NOTE PURCHASE AGREEMENT

                   5% SENIOR CUSTOM CONVERTIBLE NOTES DUE 2000

                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----

1.       DEFINITIONS..........................................................1
2.       PURCHASE AND SALE....................................................6
         (a)  Purchase........................................................6
         (b)  Form of Payment.................................................6
         (c)  Closing.........................................................7
3.       REPRESENTATIONS, WARRANTIES, COVENANTS, ETC. OF THE
         BUYER................................................................7
         (a)  Purchase for Investment.........................................7
         (b)  Accredited Investor.............................................7
         (c)  Reoffers and Resales............................................7
         (d)  Company Reliance................................................7
         (e)  Information Provided............................................7
         (f)  Absence of Approvals............................................8
         (g)  Note Purchase Agreement.........................................8
         (h)  Buyer Status....................................................8
4.       REPRESENTATIONS, WARRANTIES, COVENANTS, ETC. OF THE
         COMPANY..............................................................8
         (a)  Organization and Authority......................................8
         (b)  Qualifications..................................................8
         (c)  Capitalization..................................................9
         (d)  Material Losses.................................................9
         (e)  Concerning the Shares and the Common Stock......................10
         (f)  Corporate Authorization.........................................10
         (g)  Non-contravention...............................................10
         (h)  Approvals.......................................................11
         (i)  Information Provided............................................11
         (j)  Conduct of Business.............................................11
         (k)  SEC Filings.....................................................11
         (l)  Absence of Certain Proceedings..................................11
         (m)  Liabilities.....................................................12


<PAGE>


1.       (n)  Absence of Certain Changes......................................12
2.       (o)  Intellectual Property...........................................12
         (p)  Internal Accounting Controls....................................12
         (q)  Compliance with Law.............................................12
         (r)  Properties......................................................12
3.       (s)  Labor Relations.................................................13
         (t)  Insurance.......................................................13
         (u)  Tax Matters.....................................................13
         (v)  Investment Company..............................................13
         (w)  Absence of Brokers, Finders, Etc................................13
         (x)  No Solicitation.................................................13
         (y)  Certain Issuances of Securities.................................13
         (z)  Rights Agreement................................................14
5.       CERTAIN COVENANTS....................................................14
         (a)  Transfer Restrictions...........................................14
4.       (b)  Restrictive Legends.............................................14
         (c)  Transfer Agent Agreement........................................15
         (d)  Nasdaq Listing..................................................16
         (e)  Form D..........................................................16
         (f)  State Securities Laws...........................................16
         (g)  Certain Future Financings and Related Actions...................16
         (h)  Limitation on Certain Actions...................................17
         (i)  Use of Proceeds.................................................17
         (j)  Best Efforts....................................................17
         (k)  Debt Obligation.................................................17
6.       CONDITIONS TO THE COMPANY'S OBLIGATION TO SELL.......................18
7.       CONDITIONS TO THE BUYER'S OBLIGATION TO PURCHASE.....................18
8.       REGISTRATION RIGHTS..................................................19
         (a)  Mandatory Registration..........................................19
         (b)  Obligations of the Company......................................20
1.       (c)  Obligations of the Buyer and other Investors....................24
2.       (d)  Rule 144........................................................25
9.       INDEMNIFICATION AND CONTRIBUTION.....................................25
         (a)  Indemnification.................................................25
         (b)  Contribution....................................................26
3.       (c)  Other Rights....................................................27
10.      MISCELLANEOUS........................................................27
         (a)  Governing Law...................................................27
         (b)  Headings........................................................27
         (c)  Severability....................................................27
         
         
         <PAGE>
         
         
4.       (d)  Notices........................................................27
         (e)  Counterparts...................................................27
         (f)  Entire Agreement...............................................27
         (g)  Waiver.........................................................28
         (h)  Amendment......................................................28
         (i)  Further Assurances.............................................28
         (j)  Assignment of Certain Rights and Obligations...................28
         (k)  Expenses.......................................................28
         (l)  Termination....................................................29
         (m)  Survival.......................................................29
         (n)  Public Statements, Press Releases, Etc.........................29
         (o)  Construction...................................................29
         
         
SCHEDULES

Schedule 4(c)

ANNEXES
- -------

ANNEX I    -  5% Senior Custom Convertible Note due 2000
ANNEX II   -  Joint Escrow Instructions
ANNEX III  -  Transfer Agent Agreement
ANNEX IV   -  Common Stock Purchase Warrant
ANNEX V    -  Opinion of Cooley Godward LLP
ANNEX VI   -  Opinion of Lyon & Lyon LLP
ANNEX VII  -  Instruction to Transfer Agent
ANNEX VIII -  Opinion of Company Counsel to Be Delivered in Connection with
              Effectiveness of the Registration Statement
ANNEX IX   -  Opinion  of  Lyon  &  Lyon  LLP  to Be  Delivered  in
              Connection with Effectiveness of the Registration Statement


<PAGE>


                             NOTE PURCHASE AGREEMENT

     THIS  NOTE  PURCHASE  AGREEMENT,  dated  as  of  September  8,  1997  (this
"Agreement"),   by  and  between  SUGEN,  INC.,  a  Delaware  corporation,  with
headquarters located at 351 Galveston Drive, Redwood City, California 94063-4720
(the  "Company"),  and DELTA  OPPORTUNITY  FUND,  LTD., a British Virgin Islands
corporation (the "Buyer").

                              W I T N E S S E T H:

     WHEREAS,  the Buyer  wishes to  purchase  from the  Company and the Company
wishes to sell to the Buyer,  upon the terms and  subject to the  conditions  of
this Agreement,  a promissory note of the Company having the aggregate principal
amount  set forth on the  signature  page of this  Agreement  and which  will be
convertible  into shares of Common  Stock (such  capitalized  term and all other
capitalized terms used in this Agreement having the meanings provided in Section
1) and in connection  therewith the Company is to issue to the Buyer warrants to
purchase shares of Common Stock;

     NOW THEREFORE,  in  consideration  of the premises and the mutual covenants
contained  herein and other good and  valuable  consideration,  the  receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

     1. DEFINITIONS.

        (a) As  used in this  Agreement,  the  terms  "Agreement",  "Buyer"  and
"Company"  shall  have the  respective  meanings  assigned  to such terms in the
introductory paragraph of this Agreement.

        (b) All the  agreements or  instruments  herein  defined shall mean such
agreements or instruments as the same may from time to time be  supplemented  or
amended or the terms thereof waived or modified to the extent  permitted by, and
in accordance with, the terms thereof and of this Agreement.

        (c) The following terms shall have the following meanings (such meanings
to be equally  applicable  to both the  singular  and plural  forms of the terms
defined):

        "Affiliate"  means,  with  respect to any Person,  any other Person that
directly,  or  indirectly  through  one or  more  intermediaries,  controls,  is
controlled by or is under common control with the subject  Person.  For purposes
of this definition,  "control"  (including,  with correlative meaning, the terms
"controlled  by" and "under common control  with"),  as used with respect to any
Person,  shall mean the  possession,  directly  or  indirectly,  of the power to
direct

                                        1

<PAGE>


or cause the direction of the  management  and policies of such Person,  whether
through the ownership of voting securities or by contract or otherwise.

        "Blackout Period" means the period of up to 20 consecutive  Trading Days
after the date the  Company  notifies  the  Investors  that  they are  required,
pursuant  to  Section  8(c)(4),  to  suspend  offers  and  sales of  Registrable
Securities  as a  result  of an  event  or  circumstance  described  in  Section
8(b)(5)(A) during which period, by reason of Section 8(b)(5)(B),  the Company is
not  required  to  amend  the  Registration   Statement  or  to  supplement  the
Prospectus;  provided,  however,  that in the case of any Blackout  Period which
commences  prior to the date which is 90 days after the Closing Date the Company
shall have  determined  that public  disclosure of such event or circumstance at
such time would not be in the best interests of the Company.

        "Business  Day" means any day other than a Saturday,  Sunday or a day on
which commercial banks in The City of New York are authorized or required by law
or executive order to remain closed.

        "Claims"  means any losses,  claims,  damages,  liabilities  or expenses
(joint or several), incurred by a Person.

        "Closing  Date" means 12:00 noon,  New York City time,  on September 12,
1997 or such other mutually agreed to time.

        "Code" means the  Internal  Revenue  Code of 1986,  as amended,  and the
regulations thereunder and published interpretations thereof.

        "Common Stock" means the Common Stock,  par value $.01 per share, of the
Company.

        "Conversion  Notice"  means a Notice of  Conversion  of 5% Senior Custom
Convertible Note due 2000 substantially in the form of Exhibit A to the Note.

        "Conversion  Shares"  means the shares of Common  Stock and the  related
Preferred Share Purchase Rights issuable upon conversion of the Note.

        "Derivative  Securities" means puts, calls,  options or other derivative
securities in respect of the Common Stock.

        "Disclosure  Schedule"  means the  Disclosure  Schedule  prepared by the
Company and  furnished to the Buyer prior to the date of execution  and delivery
of this Agreement by the

                                        2

<PAGE>


Buyer.

        "ERISA" means the Employee  Retirement  Income  Security Act of 1974, as
amended, and the regulations thereunder and published interpretations thereof.

        "Escrow  Agent"  means the escrow agent  identified  in the Joint Escrow
Instructions.

        "Event of Default" shall have the meaning provided in the Note.

        "Final  Maturity  Note"  means the note of the  Company  issuable on the
maturity date of the Note in the form attached as Exhibit J to Annex I hereto.

        "Indemnified  Party" means the Company,  each of its directors,  each of
its  officers who signs the  Registration  Statement,  each Person,  if any, who
controls  the Company  within the  meaning of the 1933 Act or the 1934 Act,  any
underwriter  and  any  other  stockholder  selling  securities  pursuant  to the
Registration  Statement  or any of its  directors  or officers or any Person who
controls such  stockholder or underwriter  within the meaning of the 1933 Act or
the 1934 Act.

        "Indemnified   Person"  means  each   Investor  who  holds   Registrable
Securities and each Investor who sells such Registrable Securities in the manner
permitted under this  Agreement,  the directors,  if any, of such Investor,  the
officers,  if any, of such  Investor,  each  Person,  if any,  who  controls any
Investor within the meaning of the 1933 Act or the 1934 Act, any underwriter (as
defined in the 1933 Act) acting on behalf of an Investor who participates in the
offering of Registrable  Securities of such Investor in accordance with the plan
of  distribution  contained  in the  Prospectus  included  in  the  Registration
Statement,  the directors, if any, of such underwriter and the officers, if any,
of such underwriter,  and each Person, if any, who controls any such underwriter
within the meaning of the 1933 Act or the 1934 Act .

        "Inspector"  means any attorney,  accountant  or other agent  reasonably
acceptable to the Company  retained by an Investor for the purposes  provided in
Section 8(b)(9).

        "Interest  Shares"  means the  shares of  Common  Stock and the  related
Preferred Share Purchase Rights issuable in payment of interest on the Note.

        "Investor" means the Buyer and any permitted  transferee or assignee who
agrees to become bound by the provisions of Section 8 of this Agreement .

        "Joint Escrow Instructions" means the Joint Escrow Instructions attached
hereto

                                        3

<PAGE>


as Annex II.

        "Letter  Agreement" means the letter agreement,  dated as of the date of
this Agreement, between the Company and the Buyer.

        "Margin  Stock" shall have the meaning  provided in  Regulation G of the
Board of Governors of the Federal Reserve System (12 C.F.R. Part 207).

        "Maturity Date" shall have the meaning provided in the Note.

        "Maximum Share Amount" shall have the meaning provided in the Note.

        "Nasdaq" means the Nasdaq National Market.

        "NASD" means the National Association of Securities Dealers, Inc.

        "1996  10-K"  means  the  Company's  Annual  Report on Form 10-K for the
fiscal year ended December 31, 1996.

        "1934 Act" means the Securities Exchange Act of 1934, as amended.

        "1933 Act" means the Securities Act of 1933, as amended.

        "Non-Responsive  Investor"  means an  Investor  who does not provide the
Requested  Information to the Company at least one (1) Business Day prior to the
filing of the Registration Statement.

        "Note"  means  the 5%  Senior  Custom  Convertible  Note due 2000 of the
Company in the form of Annex I to this Agreement.

        "Other Notes" shall have the meaning provided in the Note (including any
information or documents incorporated therein by reference).

        "Person" means any natural  person,  corporation,  partnership,  limited
liability company, trust, incorporated  organization,  government,  governmental
agency or political subdivision.

        "Preferred  Share  Purchase  Rights" means the Preferred  Share Purchase
Rights  issued or  issuable  pursuant  to the Rights  Agreement  (or any similar
rights hereafter issued by the Company with respect to the Common Stock).

                                        4

<PAGE>


        "Prospectus"  means  the  prospectus  forming  part of the  Registration
Statement at the time the Registration  Statement is declared  effective and any
amendment or supplement thereto.

        "Purchase  Price" means the purchase price for the Note set forth on the
signature page of this Agreement.

        "Questionnaire" means the Prospective Purchaser  Questionnaire completed
by the Buyer.

        "Permitted  Transferee"  means  any  person  who is  (1) an  "accredited
investor"  as defined in  Regulation D under the 1933 Act and (2) a Person which
(A) has the same  investment  adviser as an Investor of the holder of any of the
Other Notes,  (B) has an investment  adviser which is under common  control with
the investment adviser to an Investor or the holder of any of the Other Notes or
(C) is an Affiliate of any Investor or the holder of any Other Note.

        "Record"  means all  pertinent  financial and other  records,  pertinent
corporate  documents and properties of the Company subject to inspection for the
purposes provided in Section 8(b)(9).

        "register,"  "registered,"  and  "registration"  refer to a registration
effected by  preparing  and filing a  Registration  Statement or  Statements  in
compliance  with the 1933 Act and pursuant to Rule 415, and the  declaration  or
ordering of effectiveness of such Registration Statement by the SEC.

        "Registrable  Securities"  means  the  Shares  and any  stock  or  other
securities  into which or for which the Common  Stock may  hereafter be changed,
converted or exchanged by the Company or its successor,  as the case may be, and
any other securities issued to holders of such Common Stock (or such shares into
which or for which such shares are so changed,  converted or exchanged) upon any
reclassification,  share combination, share subdivision, share dividend, merger,
consolidation or similar transaction or event.

        "Registration  Period" means the period from the SEC  Effective  Date to
the earlier of (i) the date which is three years after the Closing  Date (or, if
(x) the Note shall have been fully  converted  into shares of Common Stock,  (y)
the  Maturity  Date shall have  occurred or (z) the Note shall no longer  remain
outstanding, such date after which each Investor may sell all of its Registrable
Securities without registration under the 1933 Act pursuant to Rule 144, free of
any limitation on the volume of such securities which may be sold in any period)
and  (ii)  the  date on  which  the  Investors  no  longer  own any  Registrable
Securities.

                                        5

<PAGE>


        "Registration  Statement" means a registration  statement on Form S-3 of
the  Company   under  the  1933  Act  which  names  the   Investors  as  selling
stockholders.

        "Regulation D" means Regulation D under the 1933 Act.

        "Repurchase Event" shall have the meaning provided in the Note.

        "Requested  Information" means the information the Company requires from
each Investor in connection with the preparation of the Registration Statement.

        "Rights  Agreement"  means the Rights  Agreement,  dated as of August 1,
1995, by and between the Company and Boston EquiServe, as Rights Agent.

        "Rule  415"  means  Rule 415  under the 1933 Act or any  successor  rule
providing for offering securities on a delayed or continuous basis.

        "Rule 144" means  Rule 144  promulgated  under the 1933 Act or any other
similar  rule or  regulation  of the SEC that may at any time permit a holder of
any  securities  to  sell  securities  of  the  Company  to the  public  without
registration under the 1933 Act.

        "SEC" means the Securities and Exchange Commission.

        "SEC  Effective  Date"  means  the date the  Registration  Statement  is
declared effective by the SEC.

        "SEC Filing  Date" means the date the  Registration  Statement  is first
filed with the SEC pursuant to Section 8.

        "SEC  Reports"  means the 1996  10-K,  the  Company's  definitive  Proxy
Statement for its 1997 Annual  Meeting of  Stockholders,  and all other periodic
and other  reports  filed by the Company  with the SEC  pursuant to the 1934 Act
subsequent  to December 31, 1996 and prior to the date  hereof,  in each case as
filed with the SEC and  including  the  information  and  documents  (other than
exhibits) incorporated therein by reference.

        "Securities" means, collectively, the Note, the Final Maturity Note, the
Shares and the Warrants.

        "Shares"  means the  Conversion  Shares,  the  Interest  Shares  and the
Warrant Shares.

                                        6

<PAGE>


        "Subsidiary"  means any  corporation or other entity of which a majority
of the capital stock or other ownership  interests  having ordinary voting power
to elect a  majority  of the  board of  directors  or other  persons  performing
similar functions are at the time directly or indirectly owned by the Company.

        "Trading  Day"  means  at  any  time a day on  which  any of a  national
securities  exchange,  Nasdaq or such  other  securities  market as at such time
constitutes  the  principal  securities  market for the Common Stock is open for
general trading of securities.

        "Trading Price" shall have the meaning provided in the Note.

        "Transaction  Documents"  means,   collectively,   this  Agreement,  the
Securities,  the Transfer Agent Agreement and the other agreements,  instruments
and documents contemplated hereby and thereby.

        "Transfer  Agent" means  BankBoston,  N.A.,  or any  successor  thereof,
serving as transfer agent and registrar for the Common Stock,  conversion  agent
for the Note and exercise agent for the Warrants.

        "Transfer Agent  Agreement" means the Transfer Agent Agreement among the
Company, the Transfer Agent, the Buyer and the purchasers of the Other Notes, in
substantially the form attached hereto as Annex III.

        "Violation" means

        (i) any untrue  statement or alleged untrue statement of a material fact
contained in the Registration Statement or any post-effective  amendment thereof
or the omission or alleged omission to state therein a material fact required to
be stated therein or necessary to make the statements therein not misleading,

        (ii) any untrue statement or alleged untrue statement of a material fact
contained in any  Prospectus (as amended or  supplemented,  if the Company files
any  amendment  thereof or  supplement  thereto with the SEC) or the omission or
alleged  omission  to state  therein any  material  fact  necessary  to make the
statements  made  therein,  in  light  of  the  circumstances  under  which  the
statements therein were made, not misleading,

        (iii) any violation or alleged violation by the Company of the 1933 Act,
the 1934 Act, any state  securities law or any rule or regulation under the 1933
Act, the 1934 Act or any state securities law, or

                                        7

<PAGE>


        (iv) any breach or alleged  breach by any Person other than the Buyer of
any representation,  warranty,  covenant,  agreement or other term of any of the
Transaction Documents.

        "Warrants"  means Common Stock  Purchase  Warrants in the form  attached
hereto as Annex IV  initially  entitling  the holder to  purchase  the number of
shares of Common Stock determined in accordance with Section 2(a).

        "Warrant  Shares"  means  the  shares of  Common  Stock and the  related
Preferred Share Purchase Rights issuable upon exercise of the Warrants.

        2. PURCHASE AND SALE; PURCHASE PRICE.

        (a)  Purchase.  The Buyer  hereby  agrees to  purchase,  and the Company
hereby  agrees  to sell to the  Buyer,  on the  Closing  Date,  the  Note in the
principal  amount set forth on the signature  page of this  Agreement and having
the terms and conditions as set forth in the form of the Note attached hereto as
Annex I for the Purchase  Price.  In connection with the purchase of the Note by
the Buyer,  the  Company  shall issue to the Buyer at the closing on the Closing
Date  Warrants  initially  entitling  the holder to purchase  fifteen  shares of
Common Stock for each $1,000 principal amount of the Note.

        (b) Form of  Payment.  Within  three  Business  Days  after the date the
Company and the Buyer execute and deliver this Agreement,  one to the other, the
Buyer  shall  deposit  an  amount  equal  to the  Purchase  Price in  escrow  by
delivering funds in United States Dollars in the amount of the Purchase Price to
the Escrow Agent identified in the Joint Escrow Instructions against delivery by
the Company of the Note and the  Warrants,  each duly  executed on behalf of the
Company, to the Escrow Agent. Delivery of the Purchase Price to the Escrow Agent
shall be made by wire transfer of funds to:

        Citibank, N.A.
        153 East 53rd Street
        New York, New York  10043
        ABA#021000089

        For credit to A/C#37179446
        For credit to the account of Brian W. Pusch Attorney Escrow Account
        Reference:  SUGEN/Delta

By signing this  Agreement,  the Buyer and the Company agree to all of the terms
and conditions of, and become parties to, the Joint Escrow Instructions,  all of
the provisions of which are

                                        8

<PAGE>


incorporated herein by this reference as if set forth in full.

        (c)  Closing.  The issuance and sale of the Note and the issuance of the
Warrants  shall occur on the  Closing  Date at the Law Offices of Brian W Pusch,
Penthouse Suite, 29 West 57th Street,  New York, New York. At the closing,  upon
the terms and subject to the  conditions  of this  Agreement,  the Company shall
issue and deliver to the Buyer the Note and the Warrants  against payment by the
Buyer to the Company of an amount equal to the Purchase Price. Such delivery and
payment shall be effected by simultaneous release of the Notes, the Warrants and
an amount equal to the Purchase Price pursuant to the Joint Escrow Instructions.

        3. REPRESENTATIONS, WARRANTIES, COVENANTS, ETC. OF THE BUYER.

        The Buyer represents and warrants to, and covenants and agrees with, the
Company as follows:

        (a)  Purchase  for  Investment.  The  Buyer is  purchasing  the Note and
acquiring  the Warrants for its own account for  investment  and not with a view
towards the public sale or  distribution  thereof within the meaning of the 1933
Act;  the Buyer will  acquire  any Shares  issued to the Buyer  prior to the SEC
Effective  Date for its own account for  investment  and not with a view towards
the public sale or distribution thereof within the meaning of the 1933 Act prior
to the SEC  Effective  Date;  and the  Buyer  has no  intention  of  making  any
distribution,  within  the  meaning  of the 1933 Act,  of the  Shares  except in
compliance with the registration  requirements of the 1933 Act or pursuant to an
exemption therefrom;

        (b) Accredited Investor.  The Buyer is an "accredited  investor" as that
term is defined in Rule 501 of Regulation D under the 1933 Act by reason of Rule
501(a)(3) thereof;

        (c) Reoffers and Resales.  The Buyer will not,  directly or  indirectly,
offer, sell, pledge,  transfer or otherwise dispose of (or solicit any offers to
buy,  purchase or otherwise  acquire or take a pledge of) any of the  Securities
unless registered under the 1933 Act, pursuant to an exemption from registration
under the 1933 Act or in a transaction not requiring registration under the 1933
Act;

        (d) Company  Reliance.  The Buyer understands that (1) the Note is being
offered and sold and the Warrants are being issued to the Buyer,  (2) the Shares
and the Final Maturity Note are being offered to the Buyer,  (3) upon conversion
of the Note, the Conversion Shares will be issued to the Buyer, (4) the Interest
Shares will be issued to the Buyer and (5) upon  exercise of the  Warrants,  the
Warrant  Shares will be sold to the Buyer,  in each such case in reliance on one
or more exemptions from the registration requirements of the 1933 Act,

                                        9

<PAGE>


including,   without  limitation,   Regulation  D,  and  exemptions  from  state
securities  laws and that the Company is relying upon the truth and accuracy of,
and the Buyer's compliance with, the  representations,  warranties,  agreements,
acknowledgments  and  understandings  of the Buyer set forth  herein  and in the
Questionnaire, a true and accurate copy of which has been delivered by the Buyer
to the Company,  in order to determine the  availability  of such exemptions and
the  eligibility  of the Buyer to acquire  or  receive  an offer to acquire  the
Securities;  and the  information  with  respect  to the  Buyer set forth in the
Questionnaire is accurate and complete in all material respects;

        (e)  Information  Provided.  The Buyer and its  advisors,  if any,  have
requested,  received and  considered all  information  relating to the business,
properties, operations, condition (financial or other), results of operations or
prospects of the Company and  information  relating to the offer and sale of the
Note and the offer and, upon  conversion of the Note,  sale of the Shares deemed
relevant by them; the Buyer and its advisors have been afforded the  opportunity
to ask  questions  of the Company  concerning  the terms of the  offering of the
Securities and the business,  properties,  operations,  condition  (financial or
other),  results of  operations  or prospects  of the Company and have  received
satisfactory  answers to any such inquiries;  without limiting the generality of
the foregoing, the Buyer has had the opportunity to obtain and to review the SEC
Reports and the Disclosure Schedule; in connection with its decision to purchase
the Note and to acquire the  Warrants,  the Buyer has relied solely upon the SEC
Reports, the Disclosure Schedule, the representations, warranties, covenants and
agreements of the Company set forth in this Agreement and to be contained in the
other  Transaction  Documents,  as  well  as any  investigation  of the  Company
completed  by  the  Buyer  or its  advisors;  the  Buyer  understands  that  its
investment  in the  Securities  involves  a high  degree of risk;  and the Buyer
understands  that the offering of the Note is being made to the Buyer as part of
an  offering  without any minimum or maximum  amount of the  offering  (subject,
however, to the right of the Company at any time prior to execution and delivery
of this Agreement by the Company, in its sole discretion, to accept or reject an
offer by the Buyer to purchase the Note and to acquire the Warrants);

        (f) Absence of Approvals.  The Buyer  understands  that no United States
federal  or state  agency or any other  government  or  governmental  agency has
passed on or made any recommendation or endorsement of the Securities; and

        (g) Note  Purchase  Agreement.  The  Buyer has all  requisite  power and
authority,   corporate  or  otherwise,  to  execute,  deliver  and  perform  its
obligations under this Agreement and the other agreements  executed by the Buyer
in connection  herewith and to consummate the transactions  contemplated  hereby
and  thereby;  and this  Agreement  has been duly and validly  authorized,  duly
executed and delivered by the Buyer and,  assuming due execution and delivery by
the  Company,  is a valid and  binding  agreement  of the Buyer  enforceable  in
accordance with its terms, except as the enforceability hereof may be limited by
bankruptcy,

                                       10

<PAGE>


insolvency,  reorganization,  moratorium, fraudulent conveyance or other similar
laws now or  hereafter  in effect  relating to or  affecting  creditors'  rights
generally and general principles of equity, regardless of whether enforcement is
considered in a proceeding in equity or at law.

        (h) Buyer Status. The Buyer is not a "broker" or "dealer" as those terms
are  defined in the 1934 Act which is  required  to be  registered  with the SEC
pursuant to Section 15 of the 1934 Act.

        4. REPRESENTATIONS, WARRANTIES, COVENANTS, ETC. OF THE COMPANY.

        The Company  represents  and  warrants  to the Buyer that the  following
matters  are true and  correct on the date of  execution  and  delivery  of this
Agreement  and will be true and  correct on the  Closing  Date,  and the Company
covenants and agrees with the Buyer as follows:

        (a)  Organization  and  Authority.  The  Company is a  corporation  duly
organized,  validly existing and in good standing under the laws of the State of
Delaware,  and has all requisite corporate power and authority to (i) own, lease
and operate its  properties and to carry on its business as described in the SEC
Reports and as currently conducted, and (ii) to execute, deliver and perform its
obligations  under this Agreement and the other Transaction  Documents  executed
and  delivered by the Company in  connection  herewith,  and to  consummate  the
transactions contemplated hereby and thereby. The Company has no Subsidiaries.

        (b)  Qualifications.  The Company is duly  qualified to do business as a
foreign  corporation  and is in good  standing in all  jurisdictions  where such
qualification is necessary and where failure so to qualify could have a material
adverse effect on the business, properties,  operations, condition (financial or
other), results of operations or prospects of the Company.

        (c)  Capitalization.  The authorized  capital of the Company consists of
(a)  30,000,000  shares  of  Common  Stock,  of  which  13,132,738  shares  were
outstanding on September 5, 1997 and (b) 20,000,000  shares of Preferred  Stock,
$.01 par value,  of which 300,000  shares have been  designated  Series A Junior
Participating  Preferred Stock, none of which is outstanding;  from September 5,
1997 to the Closing Date there will be (x) no material increase in the number of
shares of Common Stock  outstanding  (except for shares  issued upon exercise of
options and warrants outstanding on the date hereof or options or similar rights
granted subsequent to the date of this Agreement pursuant to the Company's stock
option  plans in effect on the date of this  Agreement)  and (y) no  issuance of
shares of preferred stock of the Company. The 1996 10-K discloses as of December
31, 1996 all  outstanding  options or  warrants  for the  purchase  of, or other
rights  to  purchase  or  subscribe  for,  or  securities  convertible  into  or
exchangeable for, Common Stock or other capital stock of the Company, or

                                       11

<PAGE>


any  contracts or  commitments  to issue or sell Common  Stock or other  capital
stock of the Company or any such options,  warrants, rights or other securities;
and from December 31, 1996 to the date hereof there has been, and to the Closing
Date  there  will be, no  material  change in the  amount or terms of any of the
foregoing  except for the grant of options to  purchase  shares of Common  Stock
pursuant  to the  Company's  stock  option  plans in  effect on the date of this
Agreement  and except as  disclosed  in the SEC  Reports.  The  Company has duly
reserved from its authorized and unissued shares of Common Stock the full number
of shares  required for (a) all options,  warrants,  convertible  securities and
other rights to acquire shares of Common Stock which are outstanding and (b) all
shares of Common Stock and options and other rights to acquire  shares of Common
Stock which may be issued or granted  under the stock  option and similar  plans
which have been adopted by the Company;  and, immediately  following the Closing
Date, after giving effect to any antidilution or similar  adjustment  arising by
reason of issuance of the Note,  the Other Notes,  the Warrants and the warrants
issuable to the  purchasers  of the Other  Notes,  the total number of shares of
Common  Stock  reserved  and  required to be reserved  from the  authorized  and
unissued  shares of Common  Stock for  purposes of all such  options,  warrants,
convertible  securities,  other  rights  and  stock  option  and  similar  plans
(excluding the Note, the Other Notes, the Warrants and the warrants to be issued
to the  purchasers  of the  Other  Notes)  will be  2,941,442.  No  antidilution
adjustment  will  occur  with  respect  to any  outstanding  class or  series of
securities  of the Company,  by reason of issuance or  conversion of the Note or
the Other Notes or the  issuance or exercise of the  Warrants or the warrants to
be issued to the  purchasers  of the Other Notes except as set forth on Schedule
4(c).  The  outstanding  shares of capital  stock of the Company  have been duly
authorized  and validly issued and are fully paid and  nonassessable  and all of
such  options,  warrants  and other  rights  have been  duly  authorized  by the
Company.  None of the  holders of such  outstanding  shares of capital  stock is
subject to personal  liability solely by reason of being such a holder.  None of
the outstanding  shares of capital stock and options,  warrants and other rights
to acquire Common Stock has been issued in violation of the preemptive rights of
any  security  holder of the  Company.  The offers and sales of the  outstanding
shares of capital stock of the Company and options, warrants and other rights to
acquire Common Stock were at all relevant times either registered under the 1933
Act and applicable  state securities laws or exempt from such  requirements.  No
holder of any of the Company's securities has any rights, "demand," "piggy-back"
or otherwise,  to have such securities  registered by reason of the intention to
file, filing or effectiveness of the Registration Statement.

        (d) Material Losses.  Since the date as of which information is given in
the 1996 10-K or the June 1997 10-Q,  the Company has not  sustained any loss or
interference  with its  business  or  properties  from fire,  flood,  hurricane,
accident or other  calamity,  whether or not covered by  insurance,  or from any
labor dispute or court or governmental  action,  order or decree,  which loss or
interference  would  be  material  to  the  business,  properties,   operations,
condition  (financial  or other),  results of  operations  or  prospects  of the
Company.

                                       12

<PAGE>


        (e)  Concerning  the Shares and the Common  Stock.  The Shares have been
duly  authorized and the Conversion  Shares,  when issued upon conversion of the
Note, the Interest  Shares,  when issued in payment of interest on the Note, and
the Warrant Shares, when issued upon exercise of the Warrants,  will be duly and
validly issued,  fully paid and  non-assessable  and will not subject the holder
thereof to personal  liability  by reason of being such  holder.  The holders of
outstanding  shares  of  capital  stock  of the  Company  are  not  entitled  to
preemptive  or  other  rights  to  subscribe  for the  Shares,  the  Note or the
Warrants.  The Company has duly reserved  262,500  shares of Common Stock as the
Warrant  Shares and for issuance upon  exercise of the warrants  issuable to the
purchasers of the Other Notes and 1,930,000  shares of Common Stock for issuance
upon  conversion of the Notes and the Other Notes,  and such shares shall remain
so reserved,  and the Company  shall from time to time  reserve such  additional
shares of Common Stock as shall be required to be reserved pursuant to the Note,
as long as the Note may be converted,  and pursuant to the Warrants,  so long as
the Warrants are outstanding.  The Board of Directors has authorized officers of
the Company to reserve from time to time  additional  shares of Common Stock for
issuance upon conversion of the Note up to the Maximum Share Amount.  The Common
Stock is listed for trading on Nasdaq and (1) the  Company and the Common  Stock
meet the criteria for continued  listing and trading on Nasdaq;  (2) the Company
has not been  notified  since  January  1,  1995 by the NASD of any  failure  or
potential  failure to meet the  criteria  for  continued  listing and trading on
Nasdaq and (3) no  suspension  of trading in the Common Stock is in effect.  The
Company  knows of no reason why the Shares will not be  eligible  for listing on
Nasdaq.

        (f) Corporate  Authorization.  This Agreement and the other  Transaction
Documents have been duly and validly  authorized by the Company;  this Agreement
has been duly executed and delivered by the Company and,  assuming due execution
and delivery by the Buyer,  this Agreement is, and the Transfer Agent  Agreement
will be, when duly executed and delivered by the Company and the Transfer Agent,
and the Note,  the Final  Maturity  Note and the Warrants will be, when executed
and  delivered  by the  Company,  valid and binding  obligations  of the Company
enforceable  in  accordance  with  their   respective   terms,   except  as  the
enforceability thereof may be limited by bankruptcy, insolvency, reorganization,
moratorium,  fraudulent  conveyance  or other  similar  laws now or hereafter in
effect  relating  to  or  affecting  creditors'  rights  generally  and  general
principles  of equity,  regardless  of whether  enforcement  is  considered in a
proceeding in equity or at law.

        (g) Non-contravention. The execution and delivery of this Agreement, the
Transfer Agent Agreement,  the Note, the Final Maturity Note and the Warrants by
the  Company  and  the  consummation  by  the  Company  of the  issuance  of the
Securities  and the  other  transactions  contemplated  by this  Agreement,  the
Transfer Agent Agreement,  the Note, the Final Maturity Note and the Warrants do
not and will not,  with or without the giving of notice or the lapse of time, or
both, (i) result in any violation of any provision of the certificate of

                                       13

<PAGE>


incorporation  or  by-laws of the  Company,  (ii)  conflict  with or result in a
breach by the  Company of any of the terms or  provisions  of, or  constitute  a
default under,  or result in the  modification  of, or result in the creation or
imposition of any lien, security interest, charge or encumbrance upon any of the
properties or assets of the Company pursuant to, any indenture,  mortgage,  deed
of trust or other  agreement or instrument to which the Company is a party or by
which the Company or any of its properties or assets are bound or affected which
would have a material  adverse effect on the business,  properties,  operations,
condition  (financial  or other),  results of  operations  or  prospects  of the
Company or (iii) violate or contravene any applicable law, rule or regulation or
any applicable decree,  judgment or order of any court, United States federal or
state regulatory body,  administrative  agency or other governmental body having
jurisdiction  over the Company or any of its  properties  or assets  which would
have  a  material  adverse  effect  on  the  business,  properties,  operations,
condition  (financial  or other),  results of  operations  or  prospects  of the
Company or (iv) have any material  adverse effect on any permit,  certification,
registration,  approval, consent, license or franchise necessary for the Company
to own or lease and  operate  any of its  properties  and to conduct  any of its
business or the ability of the Company to make use thereof.

        (h) Approvals. No authorization, approval or consent of, or filing with,
any court, governmental body, regulatory agency,  self-regulatory  organization,
or stock exchange or market or the stockholders of the Company is required to be
obtained or made by the Company in connection  with the execution,  delivery and
performance of this Agreement, the Transfer Agent Agreement, the Note, the Final
Maturity  Note and the Warrants and the issuance and sale of the  Securities  as
contemplated by this Agreement and the terms of the Note and the Warrants, other
than (1) listing of the Shares on Nasdaq,  (2) registration of the resale of the
Shares under the 1933 Act as  contemplated  by Section 8, (3) as may be required
under  applicable  state securities or "blue sky" laws, and (4) filing of one or
more Forms D with respect to the Securities as required under Regulation D.

        (i)  Information  Provided.  The written  information  provided by or on
behalf of the  Company  to the Buyer and  referred  to in  Section  3(e) of this
Agreement  does not contain any untrue  statement of a material  fact or omit to
state any material fact  necessary in order to make the statements  therein,  in
the light of the  circumstances  under which they are made, not  misleading,  it
being understood that for purposes of this Section 4(i), any statement contained
in such information shall be deemed to be modified or superseded for purposes of
this Section  4(i) to the extent that a statement  in any  document  included in
such  information  which  was  prepared  or filed  with the SEC on a later  date
modifies or replaces such statement, whether or not such later prepared or filed
statement so states.

        (j) Conduct of Business.  Except as set forth in the SEC Reports,  since
December 31, 1996,  the Company has not (i) incurred any material  obligation or
liability

                                       14

<PAGE>


(absolute or  contingent)  other than in the ordinary  course of business;  (ii)
canceled,   without  payment  in  full,  any  material  notes,  loans  or  other
obligations  receivable  or other  debts or claims  held by it other than in the
ordinary  course of  business;  (iii) sold,  assigned,  transferred,  abandoned,
mortgaged, pledged or subjected to lien any of its material properties, tangible
or intangible, or rights under any material contract, permit, license, franchise
or other agreement; (iv) conducted its business in a manner materially different
from its business as conducted on such date;  (v) declared,  made or paid or set
aside for payment any cash or non-cash distribution on any shares of its capital
stock; or (vi)  consummated,  or entered into any agreement with respect to, any
transaction  or event which  would  constitute  a  Repurchase  Event.  Except as
disclosed in the SEC Reports,  the Company  owns,  possesses or has obtained all
governmental,  administrative and third party licenses,  permits,  certificates,
registrations,  approvals, consents and other authorizations necessary to own or
lease (as the case may be) and  operate  its  properties,  whether  tangible  or
intangible,  and to conduct its business or operations  as currently  conducted,
except such licenses, permits, certificates,  registrations, approvals, consents
and  authorizations  the  failure  of which to obtain  would not have a material
adverse effect on the business, properties,  operations, condition (financial or
other), results of operations or prospects of the Company.

        (k) SEC Filings. The Company has timely filed all reports required to be
filed under the 1934 Act and any other material reports or documents required to
be filed with the SEC since  January 1, 1994.  All of such reports and documents
complied, when filed, in all material respects, with all applicable requirements
of the 1933 Act and the 1934 Act. The Company meets the requirements for the use
of Form S-3 for the  registration  of the  resale of the Shares by the Buyer and
any other Investor.

        (l)  Absence  of Certain  Proceedings.  Except as  described  in the SEC
Reports, there is no action, suit,  proceeding,  inquiry or investigation before
or by any  court,  public  board or body  pending  or, to the  knowledge  of the
Company,  threatened  against or affecting  the Company  wherein an  unfavorable
decision,  ruling  or  finding  would  have a  material  adverse  effect  on the
business,  properties,  operations,  condition (financial or other),  results of
operations or prospects of the Company or the transactions  contemplated by this
Agreement or any of the other  Transaction  Documents  or which could  adversely
affect the  validity or  enforceability  of, or the  authority or ability of the
Company to perform its  obligations  under,  this  Agreement or any of the other
Transaction  Documents;  the Company  does not have  pending  before the SEC any
request  for  confidential  treatment  of  information  and to the  best  of the
Company's knowledge no such request will be made by the Company prior to the SEC
Effective Date except as set forth in the Disclosure  Schedule;  and to the best
of the Company's  knowledge there is not pending or contemplated,  and there has
been no,  investigation by the SEC involving the Company or any current director
or officer of the Company.

                                       15

<PAGE>


        (m)  Liabilities.  Except as and to the extent  disclosed,  reflected or
reserved  against  in the  financial  statements  of the  Company  and the notes
thereto included in the SEC Reports,  the Company has no material  (individually
or in the aggregate)  liability,  debt or obligation whether accrued,  absolute,
contingent  or  otherwise,  and  whether  due or to become  due.  Subsequent  to
December  31,  1996,  the Company has not  incurred  any  liabilities,  debts or
obligations of any nature  whatsoever which are individually or in the aggregate
material to the Company, other than those incurred in the ordinary course of its
business and as set forth in the SEC Reports.

        (n) Absence of Certain Changes.  Since December 31, 1996, there has been
no material adverse change in the business,  properties,  operations,  condition
(financial  or other),  results of  operations  or, to the best of the Company's
knowledge, prospects of the Company, except as disclosed in the SEC Reports.

        (o) Intellectual  Property.  Except as disclosed in the SEC Reports, the
Company (1) to its knowledge  after  reasonable  investigation  for the purposes
hereof,  owns, or possesses adequate rights to use, all patents,  patent rights,
inventions, trade secrets, know-how, proprietary techniques, including processes
and substances,  trademarks, service marks, trade names and copyrights described
or referred to in the SEC Reports or owned or used by it or which are  necessary
for the conduct of its  business,  except for failure to own or possess any such
rights as would not  individually  or in the aggregate  have a material  adverse
effect on the business, properties,  operations, condition (financial or other),
results of  operations  or prospects  of the  Company,  and (2) has no reason to
believe,  and is not aware of any claim,  that the conduct of its business  will
conflict  with any such rights of others which  conflict or claim is material to
the business, properties, operations, condition (financial or other), results of
operations or prospects of the Company.

        (p)  Internal  Accounting  Controls.  The Company  maintains a system of
internal accounting controls meeting the requirements of Section 13(b)(2) of the
1934 Act in all material respects.

        (q)  Compliance  with Law. To the best of the Company's  knowledge,  the
Company is not in violation of any statute,  law, rule,  regulation,  ordinance,
decision or order of any governmental  agency or body or any court,  domestic or
foreign,  including,  without limitation,  those relating to the use, operation,
handling,  transportation,  disposal or release of hazardous or toxic substances
or wastes or relating to the  protection or  restoration  of the  environment or
human  exposure to hazardous or toxic  substances  or wastes,  except where such
violation  would not  individually  or in the aggregate have a material  adverse
effect on the business, properties,  operations, condition (financial or other),
results of operations or prospects of the Company;  and the Company is not aware
of any pending investigation which would

                                       16

<PAGE>


reasonably be expected to lead to such a claim.

        (r)  Properties.  Except as disclosed in the  Disclosure  Schedule,  the
Company  has  good  title  to all  property  real  and  personal  (tangible  and
intangible)  and  other  assets  owned by it which  are  individually  or in the
aggregate  material to the Company,  free and clear of all  security  interests,
charges, mortgages, liens or other encumbrances, except such as are described in
the SEC  Reports  or such as do not  materially  interfere  with the use of such
property  made,  or  proposed  to be made,  by the  Company.  To the best of the
Company's  knowledge,  the leases,  licenses or other  contracts or  instruments
under which the Company leases,  holds or is entitled to use any property,  real
or personal, which individually or in the aggregate are material to the Company,
are  valid,  subsisting  and  enforceable  with only such  exceptions  as do not
materially  interfere with the use of such property made, or proposed to be made
by the Company. The Company has not received notice of any material violation of
any applicable law, ordinance,  regulation, order or requirement relating to its
owned or leased properties.

        (s)  Labor  Relations.  No  material  labor  problem  exists  or, to the
knowledge of the Company,  is imminent  with respect to any of the  employees of
the Company.

        (t) Insurance. The Company maintains insurance against loss or damage by
fire or other casualty and such other  insurance,  including but not limited to,
product  liability  insurance,  in such  amounts and  covering  such risks as is
reasonably  adequate  for the  conduct  of its  business  and the  value  of its
properties.

        (u) Tax  Matters.  The  Company has filed all  federal,  state and local
income and  franchise  tax  returns  required to be filed and has paid all taxes
shown by such  returns  to be due,  and no tax  deficiency  has been  determined
adversely to the Company  which has had (nor does the Company have any knowledge
of any tax deficiency which, if determined adversely to the Company, might have)
a material adverse effect on the business,  properties,  operations,  conditions
(financial or other), results of operations, or prospects of the Company.

        (v)  Investment  Company.  The  Company is not an  "investment  company"
within the meaning of such term under the Investment Company Act of 1940 and the
rules and regulations of the SEC thereunder.

        (w) Absence of Brokers,  Finders,  Etc.; No broker,  finder,  or similar
Person is entitled to any  commission,  fee, or other  compensation by reason of
the  transactions  contemplated  by this  Agreement  other  than Diaz & Altschul
Capital,  LLC, and the Company  shall pay, and  indemnify  and hold harmless the
Buyer from,  any claim made against the Buyer by such entity or any other Person
for any such commission, fee or other compensation.

                                       17

<PAGE>


        (x)  No  Solicitation.  No  form  of  general  solicitation  or  general
advertising was used by the Company or, to the best of its knowledge,  any other
Person  acting on behalf of the  Company,  in  respect of the  Securities  or in
connection with the offer and sale of the  Securities.  Neither the Company nor,
to its  knowledge,  any  Person  acting  on behalf of the  Company  has,  either
directly or indirectly,  sold or offered for sale to any Person any of the Notes
(other than Diaz & Altschul  Capital,  LLC with respect to the Notes) or, within
the six months  prior to the date  hereof,  any other  similar  security  of the
Company except as  contemplated by this  Agreement,  and the Company  represents
that  neither the Company  nor any Person  authorized  to act on its behalf will
sell or offer for sale any such  security  to, or solicit  any offers to buy any
such security from, or otherwise  approach or negotiate in respect thereof with,
any Person so as thereby to cause the issuance or sale of any of the  Securities
to be in violation of any of the provisions of Section 5 of the 1933 Act.

        (y)  Certain  Issuances  of  Securities.  The Company has not issued any
shares of  Common  Stock or shares  of any  series of  preferred  stock or other
securities convertible into,  exchangeable for or otherwise entitling the holder
to acquire shares of Common Stock which are subject to Section  4460(i)(1)(D) of
the rules of the NASD and which would be integrated with the sale of the Note to
the Buyer or the issuance of Conversion  Shares upon  conversion  thereof or the
issuance of the Interest  Shares in payment of interest  thereon for purposes of
such Section 4460(i)(1)(D).

        (z) Rights  Agreement.  Assuming that the Buyer does not hold any shares
of Common  Stock  other than as  acquired  pursuant  to this  Agreement  or upon
conversion  of the  Note  and  exercise  of the  Warrants,  and  subject  to the
limitations  on the  number of shares  of Common  Stock  that may be held by the
Buyer  contained  therein,  the execution and delivery of this  Agreement by the
Company,  the  issuance  of the Note and the  Warrants as  contemplated  by this
Agreement,  the issuance of the Shares upon  conversion of the Note and exercise
of the Warrants and the other  transactions  contemplated  by this Agreement and
the  other  Transaction  Documents  will not  result in the  Buyer  becoming  an
Acquiring  Person,  as defined in the Rights  Agreement;  and the holders of the
Note and the  Warrants  will be  entitled,  with  respect to the Shares,  to the
benefits available to the holders of Common Stock under the Rights Agreement.

        5. CERTAIN COVENANTS.

        (a) Transfer  Restrictions.  The Buyer  acknowledges and agrees that (1)
the Note and the  Warrants to be issued to it hereunder  and the Final  Maturity
Note  which may be issued  pursuant  to the Note have not been and are not being
registered  under the  provisions of the 1933 Act or any state  securities  laws
and, except as provided in Section 8, the Shares have not been and are not being
registered  under the 1933 Act or any state  securities laws, and that the Note,
the Warrants and the Final Maturity Note may not be transferred unless the Buyer

                                       18

<PAGE>


shall  have  delivered  to  the  Company  an  opinion  of  counsel,   reasonably
satisfactory in form, scope and substance to the Company, to the effect that the
Note,  the  Warrants  or  the  Final  Maturity  Note  to be  transferred  may be
transferred without such registration; (2) no sale, assignment or other transfer
of the Note, the Warrants or the Final Maturity Note or any interest therein may
be made except in accordance  with the terms thereof to a Permitted  Transferee;
(3) the Shares are not  transferable  in the absence of  registration  under the
1933  Act  and  applicable  state  securities  laws,  or  applicable  exemptions
therefrom;  (4) any sale of the  Securities  made in reliance on Rule 144 may be
made  only in  accordance  with the  terms  of said  Rule  and  further,  if the
exemption  provided by Rule 144 is not  available,  any resale of the Securities
under  circumstances in which the seller, or the Person through whom the sale is
made, may be deemed to be an underwriter,  as that term is used in the 1933 Act,
may require compliance with some other exemption under the 1933 Act or the rules
and  regulations  of the SEC  thereunder;  and  (5)  the  Company  is  under  no
obligation to register the Securities  (other than registration of the resale of
the  Shares in  accordance  with  Section  8) under  the 1933 Act or,  except as
provided in Section 8, to comply with the terms and  conditions of any exemption
thereunder.  The Buyer may not transfer the Shares in a  transaction  which does
not  constitute a transfer  thereof  pursuant to the  Registration  Statement in
accordance with the plan of distribution  set forth therein or in any supplement
to the Prospectus  forming part of the  Registration  Statement unless the Buyer
shall  have  delivered  to  the  Company  an  opinion  of  counsel,   reasonably
satisfactory in form,  scope and substance to the Company,  that such Shares may
be transferred without registration under the 1933 Act.

        (b) Restrictive Legends.

        (1) The  Buyer  acknowledges  and  agrees  that  the Note  shall  bear a
restrictive  legend in  substantially  the following  form (and a  stop-transfer
order may be placed against transfer of the Note):

     This Note has not been  registered  under the  Securities  Act of 1933,  as
     amended (the "1933 Act"), or any state securities laws. The issuance to the
     holder of this Note of the shares of Common Stock issuable upon  conversion
     of this Note and in payment of  interest  on this Note are not covered by a
     registration  statement  under  the 1933 Act or  registration  under  state
     securities  laws.  This Note has been  acquired,  and such  shares  must be
     acquired,  for investment only and may not be sold, transferred or assigned
     in the absence of  registration of the resale thereof under the 1933 Act or
     an opinion of counsel reasonably  satisfactory in form, scope and substance
     to the Company that such registration is not required.

        (2) The Buyer further  acknowledges  and agrees that the Warrants  shall
bear  a  restrictive   legend  in  substantially   the  following  form  (and  a
stop-transfer order may be placed

                                       19

<PAGE>


against transfer of the Warrants):

     The securities  represented by this  certificate  have not been  registered
     under the  Securities  Act of 1933, as amended.  The  securities  have been
     acquired for investment  and may not be resold,  transferred or assigned in
     the absence of an effective registration statement for the securities under
     the  Securities  Act of 1933,  as  amended,  or an opinion of counsel  that
     registration is not required under said Act.

        (3) The Buyer  further  acknowledges  and agrees that until such time as
the Shares have been registered for resale under the 1933 Act as contemplated by
Section 8, the  certificates  for the Shares,  may bear a restrictive  legend in
substantially  the  following  form  (and a  stop-transfer  order  may be placed
against transfer of the certificates for the Shares):

     The securities  represented by this  certificate  have not been  registered
     under the  Securities  Act of 1933, as amended.  The  securities  have been
     acquired for investment  and may not be resold,  transferred or assigned in
     the absence of an effective registration statement for the securities under
     the  Securities  Act of 1933,  as  amended,  or an opinion of counsel  that
     registration is not required under said Act.

        (4) Once the Registration  Statement required to be filed by the Company
pursuant to Section 8 has been declared  effective,  thereafter (1) upon request
of the Buyer the Company will substitute certificates without restrictive legend
for  certificates  for any Shares issued prior to the SEC  Effective  Date which
bear such restrictive legend and remove any stop-transfer  restriction  relating
thereto promptly,  but in no event later than three days after surrender of such
certificates  by the Buyer and (2) the Company  shall not place any  restrictive
legend on certificates for Conversion Shares issued on conversion of the Note or
Interest  Shares  issued in payment of  interest  on the Note or on any  Warrant
Shares  issued  upon  exercise  of the  Warrants  or  impose  any  stop-transfer
restriction thereon.

        (c) Transfer  Agent  Agreement.  Promptly  following  the  execution and
delivery of this  Agreement and the delivery by the Buyer of the Purchase  Price
in  accordance  with Section 2(b) hereof,  and in any event prior to the Closing
Date, the Company will (1) irrevocably instruct the Transfer Agent,  pursuant to
the Transfer Agent Agreement  substantially in the form attached hereto as Annex
III,  to issue  certificates  for the  Conversion  Shares from time to time upon
conversion  of the Note in such  amounts as  specified  from time to time to the
Company  and  the  Transfer  Agent  in  the  Conversion  Notice  surrendered  in
connection  with each such  conversion  and (2) appoint the  Transfer  Agent the
issuing agent for the Note.  The Company agrees to enter into the Transfer Agent
Agreement  substantially in the form attached hereto as Annex III on or prior to
the Closing  Date.  The  certificates  for the Shares shall be registered in the
name of the Buyer or its nominee and in such denominations to be specified by

                                       20

<PAGE>


the Buyer in  connection  with each  conversion  of the  Note or exercise of the
Warrants,  as the case may be. The Company  warrants  that except as provided in
the Transfer  Agent  Agreement no instruction  other than (x) such  instructions
referred to in this Section 5(c), (y) stop transfer  instructions to give effect
to Section 5(a) hereof prior to  registration  of the resale of the Shares under
the 1933 Act and (z) the instructions required by Section 8(b)(12) will be given
by the Company to the  Transfer  Agent and that the Shares  shall  otherwise  be
freely transferable on the books and records of the Company as and to the extent
provided in this Agreement, the Note and the Warrants. If the Buyer provides the
Company with an opinion of counsel  reasonably  satisfactory in form,  scope and
substance  to the Company that  registration  of a resale by the Buyer of any of
the Shares in accordance  with the last sentence of Section 5(a) is not required
under the 1933 Act,  the Company  shall  permit the  transfer of such shares and
promptly,  but in no event later than three days after  receipt of such opinion,
instruct  the  Transfer   Agent  to  issue  upon  transfer  one  or  more  share
certificates in such names and in such  denominations as specified by the Buyer.
Nothing in this Section 5(c) shall limit the  obligations  of the Company  under
Section 8(b)(12).

        (d) Nasdaq Listing;  Reporting  Status.  Not later than the Business Day
following the Closing Date,  the Company will file with Nasdaq an application or
other document  required by Nasdaq for the listing of the Shares with Nasdaq and
shall  provide  evidence  of such  filing  to the  Buyer.  So long as the  Buyer
beneficially  owns any portion of the Note or the  Warrants  or any Shares,  the
Company will use its best efforts to maintain the listing of the Common Stock on
Nasdaq or another national securities exchange.  During the Registration Period,
the Company  shall  timely  file all  reports  required to be filed with the SEC
pursuant  to  Section  13 or 15(d) of the 1934 Act,  and the  Company  shall not
terminate  its status as an issuer  required to file reports  under the 1934 Act
even if the 1934 Act or the rules and regulations  thereunder  would permit such
termination. So long as the Buyer owns the Note or any Shares, the Company shall
furnish to the Buyer  copies of all reports and other  information  filed by the
Company with the SEC pursuant to Sections 13, 14(a), 14(c) and 15(d) of the 1934
Act promptly, but in no event later than ten days, after the same are filed with
the SEC.

        (e) Form D. The Company  agrees to file one or more Forms D with respect
to the Securities as required under Regulation D to claim the exemption provided
by Rule 506 of Regulation D and to provide a copy thereof to the Buyer  promptly
after such filing.

        (f) State  Securities  Laws. On or before the Closing Date,  the Company
shall  take  such  action  as shall be  necessary  to  qualify,  or to obtain an
exemption  for, the Note for sale to the Buyer pursuant to this  Agreement,  the
Warrants for issuance to the Buyer pursuant to this Agreement and the Shares for
sale upon  conversion of the Note or exercise of the  Warrants,  as the case may
be, under such of the securities laws of  jurisdictions  in the United States as
shall  be  applicable  to the  sale of the Note to the  Buyer  pursuant  to this
Agreement and issuance of

                                       21

<PAGE>


the Shares upon conversion of the Note or exercise of the Warrants,  as the case
may be. Prior to the issuance of the Final Maturity Note, the Company shall take
such actions under  applicable  state  securities  laws as shall be necessary to
qualify, or to obtain an exemption for, the Final Maturity Note under such laws.
In  connection  with the  foregoing  obligations  of the Company in this Section
5(g),  the Company  shall not be  required  (1) to qualify to do business in any
jurisdiction  where it would not  otherwise  be required to qualify but for this
Section  5(g),  (2)  to  subject   itself  to  general   taxation  in  any  such
jurisdiction,  (3) to file a general  consent  to service of process in any such
jurisdiction,  (4) to provide  any  undertakings  that  cause more than  nominal
expense or burden to the  Company  or (5) to make any  change in its  charter or
by-laws which the Board of Directors of the Company determines to be contrary to
the best  interests  of the Company  and its  stockholders.  The  Company  shall
furnish the Buyer with copies of all filings, applications, orders and grants or
confirmations  of exemptions  relating to such  securities laws on or before the
Closing Date.

        (g) Certain Future Financings and Related Actions.

        (1) The  Company  shall not issue any equity  securities  or  securities
convertible into, exchangeable for or otherwise entitling the holder to acquire,
any equity  securities  of the  Company  which  would,  for  purposes of Section
4460(i)(1)(D)  of the  rules  of the  NASD  (or  any  successor  or  replacement
provision thereof),  be integrated with the sale of the Note and the issuance of
Shares upon conversion of, or in payment of interest on, the Note.

        (2) The  Company  shall not offer,  sell,  contract to sell or issue (or
engage any Person to assist the  Company in taking any such  action)  any equity
securities  or  securities  convertible  into,  exchangeable  for  or  otherwise
entitling  the holder to acquire,  any Common  Stock at a price below the market
price of the Common Stock  during the period from the date of this  Agreement to
the date on which the Registration  Statement shall have been effective with the
SEC and  available  for use by the  selling  stockholders  named  therein for 90
consecutive days; provided,  however, that nothing in this Section 5(g)(2) shall
prohibit the Company from issuing  securities (w) pursuant to compensation plans
for employees,  directors,  officers, advisers or consultants of the Company and
in  accordance  with the terms of such plans as in effect as of the date of this
Agreement, (x) upon exercise of conversion, exchange, purchase or similar rights
issued,  granted or given by the Company and  outstanding as of the date of this
Agreement,  (y) pursuant to a public offering  underwritten on a firm commitment
basis registered under the 1933 Act or (z) as part of a transaction  involving a
strategic alliance,  collaboration,  joint venture, partnership or other similar
arrangement  of the  Company  with  another  corporation,  partnership  or other
business  entity  which is engaged  in a  business  similar to or related to the
business of the Company,  so long as in the case of this clause (z) the Board of
Directors by resolution  duly adopted (and a copy of which shall be furnished to
the Buyer promptly after adoption)  determines that such issuance is fair to the
holders of each class and series of capital stock of

                                       22

<PAGE>


the  Company  and to the Buyer in respect of its equity  interest in the Company
that is represented by the Note and the Warrants; and provided further, however,
that for purposes of computing such 90-day  period,  any day on which a Blackout
Period is in effect in accordance with Section  8(b)(5)(B) shall be deemed a day
on which the Registration  Statement is effective with the SEC and available for
use by the selling stockholders named therein.

        (h)  Limitation  on  Certain  Actions.  From the date of  execution  and
delivery of this  Agreement by the parties hereto to the date of issuance of the
Note,  the Company (1) shall  comply with Article III of the Note as if the Note
were  outstanding,  (2)  shall  not  take any  action  which,  if the Note  were
outstanding,  (A) would  constitute  an Event of Default  or, with the giving of
notice or the passage of time or both,  would  constitute an Event of Default or
(B) would  constitute  a  Repurchase  Event or, with the giving of notice or the
passage of time or both, would constitute a Repurchase Event.

        (i) Use of Proceeds. The Company represents and agrees that: (1) it does
not own or have any present intention of acquiring any "margin stock" as defined
in  Regulation  G (12 CFR Part 207) of the  Board of  Governors  of the  Federal
Reserve System  ("margin  stock");  (2) the proceeds of sale of the Note will be
used for general working capital  purposes and in the operation of the Company's
business;  (3) none of such proceeds will be used, directly or indirectly (A) to
make any loan to or  investment  in any  other  Person  or (B) for the  purpose,
whether immediate,  incidental or ultimate, of purchasing or carrying any margin
stock or for the purpose of maintaining,  reducing or retiring any  indebtedness
which was originally incurred to purchase or carry any stock that is currently a
margin stock or for any other purpose which might  constitute  the  transactions
contemplated  by this  Agreement a "purpose  credit"  within the meaning of such
Regulation G; and (4) neither the Company nor any agent acting on its behalf has
taken  or  will  take  any  action  which  might  cause  this  Agreement  or the
transactions  contemplated  hereby to violate  Regulation G, Regulation T or any
other  regulation of the Board of Governors of the Federal  Reserve System or to
violate the 1934 Act, in each case as in effect now or as the same may hereafter
be in effect.

        (j) Best Efforts.  Each of the parties shall use its best efforts timely
to satisfy each of the  conditions to the other party's  obligations to sell and
purchase  the Note  set  forth in  Section  6 or 7, as the case may be,  of this
Agreement on or before the Closing Date.

        (k) Debt Obligation.  So long as any portion of the Note is outstanding,
the Company shall cause its books,  records and financial  statements to reflect
the Note as a debt of the Company in its unpaid principal  amount and,  whenever
appropriate,  as a  valid  senior  debt  obligation  of the  Company  for  money
borrowed.

        6. CONDITIONS TO THE COMPANY'S OBLIGATION TO SELL.

                                       23

<PAGE>


        The Buyer understands that the Company's obligation to sell the Note and
issue the Warrants to the Buyer pursuant to this  Agreement is conditioned  upon
satisfaction of the following conditions precedent on or before the Closing Date
(any or all of which may be waived by the Company in its sole discretion):

        (a) The  delivery by the Buyer to the Escrow Agent of an amount equal to
the Purchase Price;

        (b) On the Closing Date, no legal  action,  suit or proceeding  shall be
pending or  threatened  which seeks to restrain  or  prohibit  the  transactions
contemplated by this Agreement;

        (c) The  representations  and warranties of the Buyer  contained in this
Agreement and in the Questionnaire  shall have been true and correct on the date
of this  Agreement and on the Closing Date as if made on the Closing Date and on
or before the Closing  Date the Buyer shall have  performed  all  covenants  and
agreements  of the Buyer  required to be performed by the Buyer on or before the
Closing Date; and

        (d) No event which, if the Note were  outstanding,  (1) would constitute
an Event of  Default  or,  with the  giving of notice of the  passage of time or
both, would constitute an Event of Default shall have occurred and be continuing
or (2) would  constitute a Repurchase Event or, with the giving of notice or the
lapse of time or both,  would  constitute a Repurchase Event shall have occurred
and be  continuing  unless the Buyer shall have waived in writing such (and only
such) Event of Default or Repurchase  Event,  as the case may be, and the rights
of the Buyer  under  the Note with  respect  to such  (and only  such)  Event of
Default or Repurchase Event, as the case may be.

        7. CONDITIONS TO THE BUYER'S OBLIGATION TO PURCHASE.

        The Company understands that the Buyer's obligation to purchase the Note
and acquire the  Warrants is  conditioned  upon  satisfaction  of the  following
conditions  precedent  on or before the Closing Date (any or all of which may be
waived by the Buyer in its sole discretion):

        (a)  Delivery  by the  Company to the  Escrow  Agent of the Note and the
Warrants in accordance with this Agreement;

        (b) The Transfer  Agent shall have  executed and  delivered the Transfer
Agent Agreement;

                                       24

<PAGE>


        (c) On the Closing Date, no legal  action,  suit or proceeding  shall be
pending or  threatened  which seeks to restrain  or  prohibit  the  transactions
contemplated by this Agreement;

        (d) The  representations and warranties of the Company contained in this
Agreement  shall have been true and correct on the date of this  Agreement  and,
except for the approvals  referred to in clauses (1)-(4) of Section 4(h),  which
shall have been  obtained,  shall be true and correct on the Closing  Date as if
given on and as of the Closing  Date (except for  representations  given as of a
specific date, which representations shall be true and correct as of such date),
and on or before the Closing Date the Company shall have performed all covenants
and agreements of the Company  contained  herein required to be performed by the
Company on or before the Closing Date;

        (e) No event which, if the Note were  outstanding,  (1) would constitute
an Event of  Default  or,  with the  giving of notice or the  passage of time or
both, would constitute an Event of Default shall have occurred and be continuing
or (2) would  constitute a Repurchase Event or, with the giving of notice or the
lapse of time, or both,  would constitute a Repurchase Event shall have occurred
and be continuing;

        (f) The Company shall have delivered to the Buyer its certificate, dated
the Closing Date, duly executed by its Chief Executive Officer to the effect set
forth in subparagraphs (c), (d), and (e) of this Section 7;

        (g) The receipt by the Buyer of a  certificate,  dated the Closing Date,
of the Secretary of the Company  certifying (1) the Certificate of Incorporation
and By-Laws of the Company as in effect on the Closing Date, (2) all resolutions
of the Board of Directors (and  committees  thereof) of the Company  relating to
this  Agreement  and the  transactions  contemplated  hereby  and (3) such other
matters as reasonably requested by the Buyer;

        (h) On the Closing  Date,  the Buyer  shall have  received an opinion of
Cooley Godward LLP, counsel for the Company,  dated the Closing Date,  addressed
to the Buyer, in form, scope and substance reasonably satisfactory to the Buyer,
substantially in the form of Annex V attached hereto;

        (i) On the Closing  Date,  the Buyer  shall have  received an opinion of
Lyon & Lyon LLP,  special  counsel  for the  Company,  dated the  Closing  Date,
addressed to the Buyer, in form, scope and substance reasonably  satisfactory to
the Buyer, substantially in the form of Annex VI attached hereto; and

        (j) On the Closing Date, (i) trading in securities on the New York Stock

                                       25

<PAGE>


Exchange,  Inc., the American Stock Exchange, Inc. or Nasdaq shall not have been
suspended or  materially  limited and (ii) a general  moratorium  on  commercial
banking activities in the State of California or the State of New York shall not
have been declared by either federal or state authorities.

        8. REGISTRATION RIGHTS.

        (a) Mandatory Registration.

        (1) The Company  shall  prepare and, on or prior to the date which is 30
days after the Closing Date, file with the SEC a Registration  Statement on Form
S-3 which on the SEC Filing  Date  covers the resale by the Buyer of a number of
shares of Common  Stock  equal to (A) at least the number of  Conversion  Shares
issuable to the Buyer under the Note,  determined as if the Note,  together with
accrued and unpaid interest,  were converted in full (determined  without regard
to the limitation in the second  sentence of Section 2.1 of the Note) on the SEC
Filing Date and as if the Note were  convertible  on the SEC Filing Date, (B) at
least 100% of the Warrant Shares  issuable to the Buyer and (C) such  additional
number  of  shares  of  Common  Stock as the  Company  shall  in its  discretion
determine to register in connection with the issuance of the Interest Shares, as
Registrable  Securities,  and which Registration  Statement shall state that, in
accordance  with Rule 416 under the 1933 Act, such  Registration  Statement also
covers such  indeterminate  number of  additional  shares of Common Stock as may
become issuable upon conversion of the Note to prevent  dilution  resulting from
stock splits, stock dividends or similar transactions.  If, notwithstanding Rule
416 under the 1933 Act, the  Registration  Statement is not deemed to cover such
indeterminate  number  of  shares  of  Common  Stock as shall be  issuable  upon
conversion  of the Note  based on  changes  from time to time in the  conversion
price  thereof  such that at any time the  number  of  shares  of  Common  Stock
included in the Registration  Statement  required to be filed as provided in the
first sentence of this Section 8(a) shall be insufficient to cover the number of
shares of Common Stock issuable on conversion in full of the unconverted portion
of the Note (after  taking  into  account  any  redemptions  pursuant to Section
2.4(b) of the Note),  then  promptly,  but in no event  later than 20 days after
such  insufficiency  shall  occur,  the  Company  shall  file  with  the  SEC an
additional  Registration  Statement  on Form S-3 (which  shall not  constitute a
post-effective  amendment to the  Registration  Statement  filed pursuant to the
first  sentence of this Section  8(a))  covering such number of shares of Common
Stock as shall be sufficient to permit such conversion;  provided, however, that
nothing in this Section 8(a) shall limit the rights of the holder of the Note to
have all or a portion of the Note  redeemed  pursuant  to Section  2.4(b) of the
Note. For all purposes of this Agreement such additional  Registration Statement
shall be deemed to be the  Registration  Statement  required  to be filed by the
Company  pursuant to this Section 8(a), and the Company and the Investors  shall
have  the  same  rights  and   obligations   with  respect  to  such  additional
Registration   Statement  as  they  shall  have  with  respect  to  the  initial
Registration Statement

                                       26

<PAGE>


required to be filed by the Company pursuant to this Section 8(a).

        (2) Prior to the SEC  Effective  Date and during any time  subsequent to
the SEC  Effective  Date when the  Registration  Statement for any reason is not
available for use by any Investor for the resale of any Registrable  Securities,
the Company  shall not file any other  registration  statement or any  amendment
thereto  with the SEC  under the 1933 Act or  request  the  acceleration  of the
effectiveness of any other registration statement previously filed with the SEC,
other than (A) any  registration  statement on Form S-8 and (B) any registration
statement or amendment  which the Company is required to file or as to which the
Company is required to request acceleration pursuant to any obligation in effect
on the date of execution and delivery of this Agreement.

        (b) Obligations of the Company.  In connection with the  registration of
the Registrable Securities, the Company shall:

        (1) use its best efforts to cause the Registration Statement referred to
in Section 8(a) to become  effective  as promptly as possible  after the Closing
Date, and keep the Registration  Statement effective pursuant to Rule 415 at all
times  during the  Registration  Period.  The Company  shall  submit to the SEC,
within  three  Business  Days  after the  Company  learns  that no review of the
Registration Statement will be made by the staff of the SEC or that the staff of
the SEC has no further comments on the Registration  Statement,  as the case may
be, a request for acceleration of effectiveness of the Registration Statement to
a time and date not later than 48 hours after the  submission  of such  request;
provided,  however,  that if the Company determines that a development which has
not  been  publicly  disclosed  and  which  occurred  subsequent  to the date of
execution and delivery of this  Agreement  and prior to the SEC  Effective  Date
would  require  public  disclosure  prior to the  Registration  Statement  being
declared  effective and that such public disclosure at such time would not be in
the best  interests  of the  Company,  the Company may refrain  from making such
public  disclosure  for up to an aggregate  of 20 Trading  Days  (whether or not
consecutive), but in no event beyond the date which is 85 days after the Closing
Date and by so refraining  from making such public  disclosure the Company shall
not be deemed to have failed to use its best efforts and in connection therewith
the Company  shall not be  obligated to submit an  acceleration  request for the
Registration  Statement  during the period the Company refrains from making such
public  disclosure in accordance with this proviso.  The Company  represents and
warrants to the Investors  that (a) the  Registration  Statement  (including any
amendments or supplements thereto and prospectuses  contained  therein),  at the
time it is first filed with the SEC, at the time it is ordered  effective by the
SEC and at all times during which it is required to be effective  hereunder (and
each such  amendment and  supplement at the time it is filed with the SEC and at
all times during which it is available for use in connection  with the offer and
sale of the Registrable  Securities) shall not contain any untrue statement of a
material fact or omit to state a material fact required to be

                                       27

<PAGE>


stated  therein or necessary to make the  statements  therein not misleading and
(b) the Prospectus, at the time the Registration Statement is declared effective
by the SEC and at all times that the Prospectus is required by this Agreement to
be available for use by any Investor and, in  accordance  with Section  8(c)(4),
any  Investor  is  entitled  to  sell  Registrable  Securities  pursuant  to the
Prospectus, shall not contain any untrue statement of a material fact or omit to
state a material  fact required to be stated  therein,  or necessary to make the
statements  therein,  in light of the circumstances in which they were made, not
misleading;

        (2)  subject  to  Section  8(b)(5),  prepare  and file with the SEC such
amendments  (including   post-effective   amendments)  and  supplements  to  the
Registration  Statement  and the  Prospectus  as may be  necessary  to keep  the
Registration  Statement  effective,  and the  Prospectus  current,  at all times
during the Registration Period, and, during the Registration Period, comply with
the  provisions of the 1933 Act applicable to the Company in order to permit the
disposition  by the  Investors  of all  Registrable  Securities  covered  by the
Registration Statement;

        (3) furnish to each Investor whose  Registrable  Securities are included
in the Registration Statement and its legal counsel, (1) promptly after the same
is  prepared  and  publicly  distributed,  filed with the SEC or received by the
Company, one copy of the Registration  Statement and any amendment thereto, each
Prospectus and each amendment or supplement thereto,  (2) each letter written by
or on behalf of the  Company to the SEC or the staff of the SEC and each item of
correspondence  from  the  SEC  or  the  staff  of  the  SEC  relating  to  such
Registration  Statement  (other than any portion of any thereof  which  contains
information for which the Company has sought  confidential  treatment),  each of
which the Company hereby determines to be confidential information and which the
Buyer hereby agrees to keep confidential as a confidential  Record in accordance
with  Section  8(b)(9)  and (3) such  number of copies of a  Prospectus  and all
amendments and supplements  thereto and such other  documents,  as such Investor
may reasonably request in order to facilitate the disposition of the Registrable
Securities owned by such Investor;

        (4) subject to Section 8(b)(5), use its best efforts to (i) register and
qualify the Registrable  Securities covered by the Registration  Statement under
the securities or blue sky laws of such  jurisdictions as the Investors who hold
a majority in interest of the Registrable  Securities  reasonably request,  (ii)
prepare   and   file  in  those   jurisdictions   such   amendments   (including
post-effective   amendments)   and   supplements  to  such   registrations   and
qualifications as may be necessary to maintain the effectiveness  thereof at all
times during the Registration Period and (iii) take all other actions reasonably
necessary  or advisable to qualify the  Registrable  Securities  for sale by the
Investors in such jurisdictions;  provided,  however, that the Company shall not
be required in connection  therewith or as a condition thereto (I) to qualify to
do  business in any  jurisdiction  where it would not  otherwise  be required to
qualify but for this Section 8(b)(4), (II) to subject itself to general taxation
in any such jurisdiction, (III) to file a general consent to

                                       28

<PAGE>


service of process in any such  jurisdiction,  (IV) to provide any  undertakings
that cause more than nominal expense or burden to the Company or (V) to make any
change in its  charter or by-laws  which the Board of  Directors  of the Company
determines  to be  contrary  to the  best  interests  of  the  Company  and  its
stockholders;

        (5) (A) as promptly as practicable after becoming aware of such event or
circumstance, notify each Investor of the occurrence of an event or circumstance
of which the  Company  has  knowledge,  (x) as a result of which the  Prospectus
included in the Registration  Statement,  as then in effect,  includes an untrue
statement of a material  fact or omits to state a material  fact  required to be
stated  therein or necessary  to make the  statements  therein,  in light of the
circumstances  under which they were made,  not misleading or (y) which requires
the Company to amend or supplement the Registration Statement due to the receipt
from an  Investor  of new or  additional  information  about an  Investor or its
intended plan of distribution of its Shares,  and use its best efforts  promptly
to  prepare  a  supplement  or  amendment  to  the  Registration  Statement  and
Prospectus  to correct  such untrue  statement  or omission or to add any new or
additional  information,  and deliver a number of copies of such  supplement  or
amendment to each Investor as such Investor may reasonably request;

        (B) notwithstanding Section 8(b)(5)(A) above, if at any time the Company
notifies the  Investors as  contemplated  by Section  8(b)(5)(A)  that the event
giving rise to such notice relates to a development  involving the Company which
occurred  subsequent  to the  later  of (x) the SEC  Effective  Date and (y) the
latest  date  prior  to  such  notice  on  which  the  Company  has  amended  or
supplemented the Registration Statement,  then the Company shall not be required
to use best efforts to make such amendment during a Blackout  Period;  provided,
however,  that the aggregate number of Trading Days on which any Blackout Period
is in effect may not exceed 60 Trading Days (whether or not consecutive)  during
the period from the date which is 90 days after the Closing Date to the Maturity
Date, of which not more than 20 such Trading Days  (whether or not  consecutive)
may occur  during the period  commencing  on the date which is 90 days after the
Closing  Date and ending on the first  anniversary  of the date which is 90 days
after the Closing Date;  provided further,  however,  that the number of Trading
Days in which any Blackout  Period is in effect  during the period of 50 Trading
Days  commencing  on the date which is 90 days after the Closing  Date shall not
exceed ten Trading Days; and provided further,  however, that no Blackout Period
may commence within 40 Trading Days after the end of an earlier Blackout Period;

        (6) as  promptly  as  practicable  after  becoming  aware of such event,
notify each Investor who holds Registrable Securities being sold of the issuance
by the SEC of any  stop  order  or  other  suspension  of  effectiveness  of the
Registration Statement at the earliest possible time;

                                       29

<PAGE>


        (7) permit the Investors who hold Registrable  Securities being included
in the Registration  Statement, at such Investors' sole cost and expense (except
as  otherwise  specifically  provided  in  Section  10(k)) to review  and have a
reasonable  opportunity  to  comment  on  the  Registration  Statement  and  all
amendments and supplements thereto at least three Business Days (or such shorter
period as may reasonably be specified by the Company) prior to their filing with
the SEC; provided,  however,  that all comments by such Investors shall be given
to the Law  Offices of Brian W Pusch (or such other  counsel  as  designated  by
Investors who hold a majority in interest of the Registrable Securities proposed
to be offered) to convey to the Company;

        (8)  make  generally  available  to its  security  holders  as  soon  as
practical,  but not later  than 90 days  after the close of the  period  covered
thereby, an earning statement (in form complying with the provisions of Rule 158
under the 1933 Act)  covering a  12-month  period  beginning  not later than the
first day of the Company's  fiscal  quarter next following the effective date of
the Registration Statement;

        (9) make  available for  inspection  by any Investor and any  Inspectors
retained by any such Investor at such  Investor's  sole expense,  all Records as
shall be  reasonably  necessary  to enable each  Investor  to  exercise  its due
diligence  responsibility  with  respect  to  Section  11 of the  1933 Act as it
relates to the Registration  Statement or any amendment  thereof,  and cause the
Company's  officers to supply all information which any Inspector may reasonably
request  for  purposes  of such due  diligence;  provided,  however,  that  each
Inspector shall hold in confidence and shall not make any disclosure  (except to
an Investor) of any Record or other information which the Company  determines in
good faith to be confidential,  and of which determination the Inspectors are so
notified,  unless (i) the  disclosure  of such  Records is necessary to avoid or
correct a  misstatement  or omission  in any  Registration  Statement,  (ii) the
release of such Records is ordered  pursuant to a subpoena or other order from a
court or government  body of competent  jurisdiction or (iii) the information in
such  Records  has been made  generally  available  to the public  other than by
disclosure  in  violation  of this or any  other  agreement;  provided  further,
however,  that each Investor  understands  that in the course of exercising  the
rights  provided in this Section  8(b)(9) such Investor may come into possession
of material  non-public  information about the Company and that by reason of the
requirements  of the 1934 Act any such  Investor  who  possesses  such  material
non-public  information  may be restricted in making  purchases and sales of the
Common Stock unless such  information has been publicly  disclosed.  The Company
shall not be required to disclose any  confidential  information in such Records
to any  Inspector  until and  unless  such  Inspector  shall have  entered  into
confidentiality  agreements (in form and substance  satisfactory to the Company)
with the Company with respect thereto, substantially in the form of this Section
8(b)(9).  Each Investor  agrees that it shall,  upon learning that disclosure of
such  Records  is  sought  in or by a court or  governmental  body of  competent
jurisdiction or through other means, give prompt notice to the Company and allow
the Company, at the Company's expense, to undertake appropriate action

                                       30

<PAGE>


to prevent  disclosure  of, or to obtain a  protective  order for,  the  Records
deemed confidential. The Company shall hold in confidence and shall not make any
disclosure  of  information  concerning  an  Investor  provided  to the  Company
pursuant  to  this  Agreement  unless  (i)  disclosure  of such  information  is
necessary to comply with federal or state  securities  laws, (ii) the disclosure
of such  information is necessary to avoid or correct a misstatement or omission
in any Registration Statement,  (iii) the release of such information is ordered
pursuant  to a  subpoena  or other  order from a court or  governmental  body of
competent  jurisdiction  or  (iv)  such  information  has  been  made  generally
available  to the public  other than by  disclosure  in violation of this or any
other agreement. The Company agrees that it shall, upon learning that disclosure
of such  information  concerning  an  Investor  is  sought  in or by a court  or
governmental body of competent  jurisdiction or through other means, give prompt
notice to such Investor and allow such Investor,  at such Investor's expense, to
undertake appropriate action to prevent disclosure of, or to obtain a protective
order for, such information;

        (10)  use its  best  efforts  to cause  all the  Registrable  Securities
covered by the Registration  Statement as of the SEC Effective Date to be listed
on Nasdaq or such other principal  securities  market on which securities of the
same class or series issued by the Company are then listed or traded;

        (11)  provide  a  transfer  agent and  registrar,  which may be a single
entity, for the Registrable Securities not later than the SEC Effective Date;

        (12) cooperate with the Investors who hold Registrable  Securities being
offered to facilitate the timely  preparation and delivery of certificates  (not
bearing any  restrictive  legends)  representing  Registrable  Securities  to be
offered pursuant to the Registration  Statement and enable such  certificates to
be in such  denominations or amounts as the Investors may reasonably request and
registered in such names as the  Investors may request;  and, not later than the
SEC Effective  Date,  the Company shall  deliver,  and shall cause legal counsel
selected by the Company to deliver,  (i) to the  Transfer  Agent (with copies to
the Investors  whose  Registrable  Securities are included in such  Registration
Statement) an instruction substantially in the form attached hereto as Annex VII
and (ii) to the  Investors  whose  Registrable  Securities  are included in such
Registration  Statement and, if required by the Transfer  Agent, to the Transfer
Agent opinions of counsel,  in the forms attached hereto as Annex VIII and Annex
IX; and

        (13) during the  Registration  Period,  the Company shall not bid for or
purchase  any Common  Stock or any right to purchase  Common Stock or attempt to
induce any Person to purchase any such  security or right if such bid,  purchase
or attempt would in any way limit the right of the Investors to sell Registrable
Securities by reason of the limitations set forth in Regulation M under the 1934
Act.

                                       31

<PAGE>


        (c) Obligations of the Buyer and other Investors. In connection with the
registration  of the  Registrable  Securities,  the  Investors  shall  have  the
following obligations:

        (1) It shall be a condition  precedent to the obligations of the Company
to complete  the  registration  pursuant to this  Agreement  with respect to the
Registrable Securities of a particular Investor that such Investor shall furnish
to the Company such information  regarding  itself,  the Registrable  Securities
held by it and the intended method of disposition of the Registrable  Securities
held by it as shall be reasonably  required to effect the  registration  of such
Registrable  Securities and shall execute such documents in connection with such
registration as the Company may reasonably  request.  At least four (4) Business
Days prior to the first anticipated  filing date of the Registration  Statement,
the Company shall notify each Investor of the  Requested  Information  if any of
such  Investor's  Registrable  Securities  are  eligible  for  inclusion  in the
Registration Statement. If at least one (1) Business Day prior to the SEC Filing
Date the Company has not received the  Requested  Information  from an Investor,
then  the  Company  may  file  the  Registration   Statement  without  including
Registrable Securities of such Non-Responsive Investor;

        (2) Each  Investor  by such  Investor's  acceptance  of the  Registrable
Securities  agrees to cooperate with the Company as reasonably  requested by the
Company  in  connection  with the  preparation  and  filing of the  Registration
Statement  hereunder,  unless such  Investor  has  notified  the Company of such
Investor's  election to exclude all of such  Investor's  Registrable  Securities
from the Registration Statement;

        (3) Each Investor  agrees that it will not effect any disposition of the
Registrable  Securities except as contemplated in the Registration  Statement or
as otherwise in  compliance  with  applicable  securities  laws and that it will
promptly notify the Company of any material changes in the information set forth
in  the  Registration   Statement   regarding  such  Investor  or  its  plan  of
distribution;  each Investor  agrees (a) to notify the Company in the event that
such Investor  enters into any material  agreement with a broker or a dealer for
the sale of the Registrable  Securities through a block trade, special offering,
exchange  distribution or a purchase by a broker or dealer and (b) in connection
with such  agreement,  to provide to the  Company  in  writing  the  information
necessary to prepare any supplemental  prospectus  pursuant to Rule 424(c) under
the 1933 Act which is required with respect to such transaction;

        (4) Each  Investor  acknowledges  that  during  the times  specified  in
Section  8(b)(5) or 8(b)(6) the Company must  suspend the use of the  Prospectus
until such time as an amendment to the Registration  Statement has been filed by
the Company  and  declared  effective  by the SEC,  the  Company has  prepared a
supplement to the Prospectus or the Company has filed an appropriate report with
the SEC pursuant to the 1934 Act. Each Investor  hereby  covenants  that it will
not sell any  Registrable  Securities  pursuant to the  Prospectus in accordance
with

                                       32

<PAGE>


Section 8(b)(5) or 8(b)(6) during the period commencing at the time at which the
Company  gives  such  Investor  notice  of  the  suspension  of  the  use of the
Prospectus  and ending at the time the Company gives such  Investor  notice that
such Investor may thereafter  effect sales pursuant to the Prospectus,  or until
the Company delivers to such Investor an amended or supplemented Prospectus;

        (5) In connection with any sale of Registrable  Securities which is made
by an Investor  pursuant to the Registration  Statement (A) if such sale is made
through a broker,  such Investor shall instruct its broker or brokers to deliver
the  Prospectus to the  purchaser or  purchasers  in connection  with such sale,
shall  supply  copies of such  Prospectus  to such broker or brokers (B) if such
sale is made in a  transaction  directly  with a  purchaser  and not through the
facilities of any securities exchange or market, such Investor shall deliver, or
cause to be delivered, the Prospectus to such purchaser; and (C) if such sale is
made by any means  other  than  those  described  in the  immediately  preceding
clauses (A) and (B),  such Investor  shall  otherwise  use its  reasonable  best
efforts to comply  with the  prospectus  delivery  requirements  of the 1933 Act
applicable to such sale; and

        (6) Each Investor agrees to notify the Company  promptly after the event
of the completion of the sale by such Investor of all Registrable  Securities to
be sold by such Investor pursuant to the Registration Statement.

        (d) Rule  144.  With a view to making  available  to the  Investors  the
benefits of Rule 144, the Company agrees to:

        (1) to promptly  furnish to each  Investor so long as such Investor owns
Registrable  Securities,  such  information  as may be  necessary  to permit the
Investors  to  sell  Registrable   Securities   pursuant  to  Rule  144  without
registration; and

        (2) if at any time the Company is not required to file such reports with
the SEC under  Sections 13 or 15(d) of the 1934 Act, to use its best efforts to,
upon the request of an Investor,  make publicly  available other  information so
long as is necessary to permit  publication by brokers and dealers of quotations
for the Common Stock and sales of the Registrable  Securities in accordance with
Rule 15c2-11 under the 1934 Act.

        9. INDEMNIFICATION AND CONTRIBUTION.

        (a) Indemnification.

        (1) To the extent not  prohibited  by  applicable  law, the Company will
indemnify and hold harmless each Indemnified  Person against any Claims to which
any of them may

                                       33

<PAGE>


become  subject under the 1933 Act, the 1934 Act or  otherwise,  insofar as such
Claims (or actions or proceedings,  whether commenced or threatened,  in respect
thereof)  arise  out  of or  are  based  upon  any  Violation.  Subject  to  the
restrictions  set forth in Section  9(a)(3)  with respect to the number of legal
counsel,  the Company shall  reimburse  the Investors and each such  controlling
Person,  promptly as such expenses are incurred and are due and payable, for any
documented  reasonable  legal fees or other  documented and reasonable  expenses
incurred by them in connection with  investigating  or defending any such Claim.
Notwithstanding  anything to the contrary contained herein, the  indemnification
agreement  contained  in this  Section  9(a)(1)  shall not apply to: (I) a Claim
arising out of or based upon a Violation  which  occurs in reliance  upon and in
conformity  with  information  relating to an  Indemnified  Person  furnished in
writing  to the  Company  by such  Indemnified  Person or  underwriter  for such
Indemnified  Person  expressly for use in connection with the preparation of the
Registration  Statement or any such amendment thereof or supplement  thereto, if
such  Prospectus  was timely made  available by the Company  pursuant to Section
8(b)(3)  hereof;  and  (II)  amounts  paid in  settlement  of any  Claim if such
settlement  is  effected  without the prior  written  consent of the Company and
(III) an Indemnified Person with respect to a Claim which arises solely from the
failure  of such  Indemnified  Person  to comply in any  material  respect  with
Section 8(c)(4) or 8(c)(5). Such indemnity shall remain in full force and effect
regardless of any investigation  made by or on behalf of the Indemnified  Person
and shall survive the transfer of the Registrable Securities by the Investors.

        (2) In connection with the Registration Statement,  each Investor agrees
to indemnify  and hold  harmless,  to the same extent and in the same manner set
forth in Section 9(a)(1),  each Indemnified Party against any Claim to which any
of them may  become  subject,  under  the 1933 Act,  the 1934 Act or  otherwise,
insofar as such Claim arises out of or is based upon any Violation, in each case
to the extent (and only to the extent)  that such  Violation  occurs in reliance
upon and in conformity with written information furnished to the Company by such
Investor expressly for use in connection with such Registration  Statement;  and
such Investor will reimburse any legal or other expenses  reasonably incurred by
them in connection  with  investigating  or defending any such Claim;  provided,
however,  that the indemnity  agreement  contained in this Section 9(a)(2) shall
not apply to  amounts  paid in  settlement  of any Claim if such  settlement  is
effected without the prior written consent of such Investor, which consent shall
not be unreasonably  withheld;  provided,  further,  however,  that the Investor
shall be liable  under this  Section  9(a)(2) for only that amount of a Claim as
does not exceed the amount by which the proceeds to such Investor as a result of
the sale of  Registrable  Securities  pursuant  to such  Registration  Statement
exceeds the amount paid by such Investor for such Registrable  Securities.  Such
indemnity shall remain in full force and effect  regardless of any investigation
made by or on behalf of such Indemnified Party and shall survive the transfer of
the  Registrable  Securities by the Investors.  Notwithstanding  anything to the
contrary  contained  herein,  the  indemnification  agreement  contained in this
Section  9(a)(2) with respect to any preliminary  prospectus  shall not inure to
the  benefit of any  Indemnified  Party if the untrue  statement  or omission of
material fact

                                       34

<PAGE>


contained in the  preliminary  prospectus was corrected on a timely basis in the
Prospectus, as then amended or supplemented.

        (3) Promptly after receipt by an Indemnified Person or Indemnified Party
under this Section 9(a) of notice of the  commencement of any action  (including
any governmental action), such Indemnified Person or Indemnified Party shall, if
a Claim in respect  thereof is to be made against any  indemnifying  party under
this  Section  9(a),   deliver  to  the  indemnifying  party  a  notice  of  the
commencement  thereof  and the  indemnifying  party  shall  have  the  right  to
participate in, and, to the extent the  indemnifying  party so desires,  jointly
with any other indemnifying  party similarly  noticed,  to assume control of the
defense thereof with counsel  reasonably  satisfactory to the Indemnified Person
or the  Indemnified  Party,  as the  case  may be;  provided,  however,  that an
Indemnified  Person or Indemnified  Party shall have the right to retain its own
counsel with the fees and expenses to be paid by the indemnifying  party, if, in
the  reasonable  opinion of counsel  retained  by the  indemnifying  party,  the
representation  by such counsel of the Indemnified  Person or Indemnified  Party
and the  indemnifying  party would be  inappropriate  due to actual or potential
differing interests between such Indemnified Person or Indemnified Party and any
other party  represented by such counsel in such proceeding;  provided  further,
however,  that no  indemnifying  person  shall be  responsible  for the fees and
expenses of more than one separate counsel for all Indemnified Persons hereunder
and one  separate  counsel in each  jurisdiction  in which a claim is pending or
threatened.  The failure to deliver  notice to the  indemnifying  party within a
reasonable  time of the  commencement  of any such action shall not relieve such
indemnifying  party of any liability to the  Indemnified  Person or  Indemnified
Party under this Section 9(a), except to the extent that the indemnifying  party
is prejudiced in its ability to defend such action. The indemnification required
by this  Section 9(a) shall be made by periodic  payments of the amount  thereof
during the course of the investigation or defense, as such expense, loss, damage
or liability is incurred and is due and payable.

        (b) Contribution.  To the extent any  indemnification by an indemnifying
party as set  forth in  Section  9(a)  above is  applicable  by its terms but is
prohibited or limited by law, the indemnifying  party agrees to make the maximum
contribution  with respect to any amounts for which it would otherwise be liable
under Section 9(a) to the fullest extent  permitted by law. In  determining  the
amount of contribution to which the respective parties are entitled, there shall
be considered the relative fault of each party, the parties' relative  knowledge
of and access to  information  concerning  the matter with  respect to which the
claim was  asserted,  the  opportunity  to correct and prevent any  statement or
omission  and  any  other  equitable   considerations   appropriate   under  the
circumstances;  provided,  however, that (a) no contribution shall be made under
circumstances  where the maker  would not have been  liable for  indemnification
under the fault  standards  set forth in Section  9(a),  (b) no Person guilty of
fraudulent  misrepresentation  (within the meaning of Section  11(f) of the 1933
Act) shall be entitled to contribution  from any other Person who was not guilty
of such fraudulent misrepresentation and (c) contribution by any

                                       35

<PAGE>


seller of  Registrable  Securities  shall be  limited to the amount by which the
proceeds  received by such seller from the sale of such  Registrable  Securities
exceeds the amount paid by such Investor for such Registrable Securities.

        (c) Other Rights. The indemnification and contribution  provided in this
Section  shall be in addition to any other rights and remedies  available at law
or in equity.

        10. MISCELLANEOUS.

        (a) Governing Law. THIS AGREEMENT  SHALL BE GOVERNED BY AND  INTERPRETED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF CALIFORNIA.

        (b) Headings.  The headings,  captions and footers of this Agreement are
for  convenience  of  reference  and  shall  not form  part of,  or  affect  the
interpretation of, this Agreement.

        (c) Severability. If any provision of this Agreement shall be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect the validity or  enforceability of the remainder of this Agreement or the
validity or enforceability of this Agreement in any other jurisdiction.

        (d)  Notices.  Any notices  required or  permitted to be given under the
terms of this Agreement shall be in writing and shall be sent by mail,  personal
delivery,  by  telephone  line  facsimile  transmission  or courier and shall be
effective five days after being placed in the mail, if mailed,  or upon receipt,
if delivered personally, by telephone line facsimile transmission or by courier,
in each case  addressed to a party at such party's  address (or  telephone  line
facsimile  transmission  number) shown in the  introductory  paragraph or on the
signature  page of this  Agreement  or such other  address  (or  telephone  line
facsimile  transmission  number) as a party shall have provided by notice to the
other party in accordance with this provision.  In the case of any notice to the
Company,  such notice should be addressed to the Company at its address shown in
the introductory paragraph of this Agreement, Attention: Vice President, Finance
(telephone line facsimile number (650) 306-4016), and a copy shall also be given
to: Cooley Godward LLP, 3000 El Camino Real,  Five Palo Alto Square,  Palo Alto,
California 94306, Attention: Brian C. Cunningham, Esq. (telephone line facsimile
transmission number (650) 857-0663), and in the case of any notice to the Buyer,
a copy shall be given to: Law Offices of Brian W.  Pusch,  Penthouse  Suite,  29
West  57th  Street,   New  York,  New  York  10019   (telephone  line  facsimile
transmission  number  (212)  980-7055),  in each  case  with a copy  to:  Diaz &
Altschul  Capital,  LLC, 745 Fifth Avenue,  Suite 3001, New York, New York 10022
(telephone line facsimile transmission number (212) 751-5757).

                                       36

<PAGE>


        (e) Counterparts.  This Agreement may be executed in counterparts and by
the parties hereto on separate counterparts, each of which shall be deemed to be
an  original  but all of  which  together  shall  constitute  one  and the  same
instrument.  A telephone line facsimile transmission of this Agreement bearing a
signature on behalf of a party hereto shall be legal and binding on such party.

        (f) Entire Agreement;  Benefit.  This Agreement,  including the Annexes,
Schedule and Disclosure Schedule, and the Letter Agreement constitute the entire
agreement  among the parties  hereto with respect to the subject  matter hereof.
There are no restrictions,  promises,  warranties,  or undertakings,  other than
those set forth or referred to herein and therein. This Agreement, including the
Annexes,  Schedule and Disclosure  Schedule,  and the Letter Agreement supersede
all prior agreements and  understandings,  whether written or oral,  between the
parties hereto with respect to the subject matter hereof. This Agreement and the
Letter  Agreement  and the terms and  provisions  hereof and thereof are for the
sole benefit of only the Company, the Buyer and their respective  successors and
permitted assigns.

        (g) Waiver.  Failure of any party to exercise  any right or remedy under
this  Agreement or otherwise,  or delay by a party in  exercising  such right or
remedy,  or course of dealing  between the parties shall not operate as a waiver
thereof or an amendment hereof,  nor shall any single or partial exercise of any
such right or power,  or any abandonment or  discontinuance  of steps to enforce
such a right or  power,  preclude  any  other or  further  exercise  thereof  or
exercise of any other right or power.

        (h)  Amendment.  No  amendment,   modification,   waiver,  discharge  or
termination  of any provision of this  Agreement nor consent to any departure by
the Buyer or the Company  therefrom  shall in any event be effective  unless the
same shall be in writing and signed by the party to be charged with enforcement,
and then shall be effective  only in the  specific  instance and for the purpose
for which given.  No course of dealing  between the parties hereto shall operate
as an amendment of this Agreement.

        (i) Further  Assurances.  Each party to this  Agreement will perform any
and all acts and execute any and all  documents as may be  necessary  and proper
under the  circumstances in order to accomplish the intents and purposes of this
Agreement and to carry out its provisions.

        (j)  Assignment  of  Certain  Rights and  Obligations.  The rights of an
Investor  under  Sections  5(a),  5(b),  8  and 9 of  this  Agreement  shall  be
automatically  assigned by such Investor to any transferee of all or any portion
of such Investor's  Registrable Securities (or all or any portion of the Note or
the Warrants) who is a Permitted Transferee only if: (1) such Investor agrees in
writing with such transferee to assign such rights, and a copy of such

                                       37

<PAGE>


agreement  is  furnished  to the  Company  within a  reasonable  time after such
assignment,  (2) the Company is, within a reasonable  time after such  transfer,
furnished with notice of (A) the name and address of such transferee and (B) the
securities  with  respect  to  which  such  rights  and  obligations  are  being
transferred,  (3) immediately  following such transfer or assignment the further
disposition  of  Registrable   Securities  by  the  transferee  or  assignee  is
restricted  under the 1933 Act and applicable  state  securities laws, (4) at or
before the time the Company  received the notice  contemplated  by clause (2) of
this sentence the  transferee  agrees in writing with the Company to be bound by
all of the provisions  contained in Sections 5(a),  5(b), 8 and 9 hereof and (5)
immediately  after such transfer such transferee holds at least 50,000 shares of
Common Stock or a portion (which, if applicable, may be all) of the Notes and/or
Warrants which at the time of such transfer is  convertible  into or exercisable
for 50,000  shares of Common Stock (or any  combination  thereof) or such lesser
amount into which the Note is convertible at the time of such transfer. Upon any
such transfer,  the Company shall be obligated to such transferee to perform all
of  its  covenants  under  Sections  5, 8 and 9 of  this  Agreement  as if  such
transferee  were the Buyer.  In  connection  with any such  transfer the Company
shall,  at its sole cost and expense,  promptly  after such  transfer  take such
actions as shall be reasonably  acceptable to the transferring Investor and such
transferee to assure that the Registration  Statement and related Prospectus are
available for use by such transferee for sales of the Registrable  Securities in
respect of which such rights and obligations have been so transferred.

        (k)  Expenses.  All  reasonable  expenses  incurred in  connection  with
registrations,  filings or  qualifications  pursuant to this Agreement  shall be
paid by the Company,  including,  without limitation, all registration,  listing
and  qualifications  fees,  printers  and  accounting  fees  and  the  fees  and
disbursements  of counsel for the Company but excluding (a) fees and expenses of
investment bankers retained by any Investor,  (b) brokerage commissions incurred
by any Investor and (c) fees and disbursements of counsel for the Investors. The
Company  shall pay on demand  all  expenses  incurred  by the  Buyer,  including
reasonable  attorneys' fees and expenses,  as a consequence of, or in connection
with, (1) any default or breach of any of the Company's obligations set forth in
the Transaction  Documents and (2) the enforcement or restructuring of any right
of,  including  the  collection  of  any  payments  due,  the  Buyer  under  the
Transaction  Documents,  including  any action or  proceeding  relating  to such
enforcement  or any order,  injunction or other process  seeking to restrain the
Company from paying any amount due the Buyer.  Except as  otherwise  provided in
this  Section  10(k),  each of the  Company  and the  Buyer  shall  bear its own
expenses in connection  with this  Agreement and the  transactions  contemplated
hereby.

        (l)  Termination.  The  Buyer  shall  have the right to  terminate  this
Agreement by giving notice to the Company at any time at or prior to the Closing
Date if:

        (1) the Company shall have failed,  refused,  or been unable at or prior
to the

                                       38

<PAGE>


date of such  termination  of this  Agreement to perform any of its  obligations
hereunder;

        (2) any other  condition  of the Buyer's  obligations  hereunder  is not
fulfilled; or

        (3) the closing  shall not have  occurred on a Closing Date on or before
September 25, 1997, other than solely by reason of a breach of this Agreement by
the Buyer.

Any such termination shall be effective upon the giving of notice thereof by the
Buyer. Upon such termination,  the Buyer shall have no further obligation to the
Company  hereunder  and the Company  shall remain  liable for any breach of this
Agreement or the other documents  contemplated hereby which occurred on or prior
to the date of such termination.

        (m) Survival. The respective representations,  warranties, covenants and
agreements  of the Company and the Buyer  contained  in this  Agreement  and the
documents  delivered  in  connection  with  this  Agreement  shall  survive  the
execution and delivery of this Agreement and the Closing  hereunder and delivery
of and  payment  for the Note and  issuance of the  Warrants,  and shall  remain
operative and in full force and effect regardless of any  investigation  made by
or on behalf of the Buyer or any Person  controlling  or acting on behalf of the
Buyer or by the  Company  or any Person  controlling  or acting on behalf of the
Company.

        (n) Public Statements,  Press Releases,  Etc.; The Company and the Buyer
shall have the right to approve before  issuance any press releases or any other
public  statements  with  respect  to  the  transactions   contemplated  hereby;
provided,  however,  that the  Company  shall be  entitled,  without  the  prior
approval of the Buyer, to make any press release or other public disclosure with
respect to such  transactions as is required by applicable law and  regulations,
including  the 1933 Act and the rules  and  regulations  promulgated  thereunder
(although  the Buyer shall be  consulted by the Company in  connection  with any
such press release or other public  disclosure prior to its release and shall be
provided with a copy thereof).

        (o) Construction.  The language used in this Agreement will be deemed to
be the language  chosen by the parties to express  their mutual  intent,  and no
rules of strict construction will be applied against any party.

                                       39

<PAGE>


        IN WITNESS  WHEREOF,  the parties have caused this  Agreement to be duly
executed by their respective  officers  thereunto duly authorized as of the date
first set forth above.


Principal Amount: $

Purchase Price:   $


                                             SUGEN, INC.


                                             By:  ______________________________
                                                 Name:
                                                 Title:


                                             DELTA OPPORTUNITY FUND, LTD.



                                             By ________________________________
                                                 Name:
                                                 Title:

                                             Address:
                                                  c/o International Fund 
                                                  Administration, Ltd.
                                                  Suite 464
                                                  48 Par La Ville Road
                                                  Hamilton HM11
                                                  Bermuda

                                             Facsimile No.:  (441) 295-9637


                                       40




                                     Annex I
                                       to
                                  Note Purchase
                                    Agreement

THIS NOTE HAS NOT BEEN  REGISTERED  UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE "1933 ACT"),  OR ANY STATE  SECURITIES  LAWS. THE ISSUANCE TO THE HOLDER OF
THIS NOTE OF THE SHARES OF COMMON STOCK  ISSUABLE  UPON  CONVERSION OF THIS NOTE
AND IN  PAYMENT  OF  INTEREST  ON THIS NOTE ARE NOT  COVERED  BY A  REGISTRATION
STATEMENT UNDER THE 1933 ACT OR REGISTRATION  UNDER STATE  SECURITIES LAWS. THIS
NOTE HAS BEEN ACQUIRED,  AND SUCH SHARES MUST BE ACQUIRED,  FOR INVESTMENT  ONLY
AND MAY NOT BE SOLD,  TRANSFERRED OR ASSIGNED IN THE ABSENCE OF  REGISTRATION OF
THE  RESALE  THEREOF  UNDER THE 1933 ACT OR AN  OPINION  OF  COUNSEL  REASONABLY
SATISFACTORY IN FORM, SCOPE AND SUBSTANCE TO THE COMPANY THAT SUCH  REGISTRATION
IS NOT REQUIRED.

THIS NOTE IS ISSUED PURSUANT TO A NOTE PURCHASE AGREEMENT, DATED AS OF SEPTEMBER
8, 1997,  BY AND BETWEEN THE COMPANY AND THE  ORIGINAL  HOLDER OF THIS NOTE,  AS
AMENDED FROM TIME TO TIME, AND THE HOLDER OF THIS NOTE AND THIS NOTE ARE SUBJECT
TO CERTAIN OF THE TERMS OF THE NOTE PURCHASE AGREEMENT.

THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS PROVIDED IN SECTION 8.7.

The Holder and any assignee,  by acceptance of this Note,  acknowledge and agree
that, by reason of the provisions of SECTION 2.3(b),  following  conversion of a
portion of this Note, the unpaid and unconverted  principal  amount of this Note
represented by this Note may be less than the amount stated on the face hereof.


                                   SUGEN, INC.

                        5% SENIOR CUSTOM CONVERTIBLE NOTE

No. ________                                                          $_________
New York, New York
September    , 1997

                                        1

<PAGE>


         FOR VALUE RECEIVED,  SUGEN, INC., a Delaware  corporation  (hereinafter
called the  "Company"),  hereby  promises to pay to [INSERT  NAME AND ADDRESS OF
BUYER],  or  registered  assigns (the  "Holder") or order,  the sum of _________
Dollars  ($_________________),  on the Maturity Date, and to pay interest on the
unpaid  principal  balance hereof at the  Applicable  Rate from the date hereof,
until the same becomes due and payable, whether at maturity or upon acceleration
or by repurchase in accordance with the terms hereof or otherwise. Any amount of
principal  of or  interest  on this Note  which is not paid when due shall  bear
interest at the Default  Rate from the due date  thereof  until the same is paid
("Default  Interest").  Interest  shall be payable  in arrears on each  Interest
Payment  Date,  commencing  on  November  15,  1997,  on  the  principal  amount
outstanding  on such date.  Interest on this Note shall be computed on the basis
of a 360-day year of 12 30-day months and actual days elapsed. No interest shall
be payable on an Interest Payment Date on any portion of the principal amount of
this Note which shall have been  converted  or redeemed  prior to such  Interest
Payment  Date so long as the  Company  shall  have  complied  in full  with  its
obligations with respect to such conversion or redemption.

         Except as otherwise  specifically  provided in Article VI, all payments
of principal of and premium,  if any, and interest on this Note shall be made in
lawful money of the United  States of America,  or, at the option of the Company
and subject to the  provisions  of this Note,  interest  payable on the Interest
Payment  Dates may be paid in whole or in part in fully  paid and  nonassessable
shares of Common  Stock.  All cash  payments  shall be made by wire  transfer of
immediately  available funds to such account as the Holder may from time to time
designate by written  notice in  accordance  with the  provisions  of this Note.
Whenever any amount  expressed to be due by the terms of this Note is due on any
day which is not a  Business  Day,  the same  shall  instead  be due on the next
succeeding day which is a Business Day and, in the case of any Interest  Payment
Date which is not the date on which this Note is paid in full,  the extension of
the due date thereof shall not be taken into account for purposes of determining
the amount of interest due on such date. Certain  capitalized terms used in this
Note are defined in Article VII.

         The  obligations  of the Company under this Note shall rank in right of
payment on a parity with all other unsubordinated obligations of the Company for
indebtedness for borrowed money or the purchase price of property.  This Note is
issued  pursuant to the Note Purchase  Agreement and the Holder of this Note and
the Note are subject to the terms of the Note Purchase Agreement.  The aggregate
principal amount of this Note and the Other Notes is $17,500,000.00.

         The following terms shall apply to this Note:

                                        2

<PAGE>


                                    ARTICLE I

                     INTEREST IN COMMON STOCK; NO PREPAYMENT

         1.1 Issuance of Common Stock in Lieu of Cash Interest.

         (a) If the Company  exercises  its option to make a payment of interest
on this Note wholly or partly in shares of Common Stock (herein sometimes called
the "Stock Payment  Option"),  the issuance of Payment Shares upon such exercise
of the Stock Payment Option shall have been authorized by the Board of Directors
of the Company.

         (b) The Company  shall not be permitted  to exercise the Stock  Payment
Option with respect to any payment of interest on this Note if:

         (i) the  number  of shares of Common  Stock  authorized,  unissued  and
     unreserved  for  all  purposes,  or  held  in the  Company's  treasury,  is
     insufficient  to pay the  portion  of such  interest  to be paid in  Common
     Stock;

         (ii) the issuance or delivery of Payment Shares or the public resale of
     such  Payment  Shares by the  Holder  would  require  registration  with or
     approval of any  governmental  authority  under any law or regulation,  and
     such  registration  or approval has not been effected or obtained or is not
     in effect and the  Registration  Statement  is  unavailable  for use by the
     Holder for the resale of the Payment Shares;  provided,  however, that with
     respect to compliance with the securities or blue sky laws of the states of
     the United  States,  the  requirements  of this clause (ii) shall be deemed
     satisfied  if at the  applicable  time the  Company is in  compliance  with
     Section 8(b) of the Note Purchase Agreement;

         (iii) the Payment  Shares  shall not at the time of issuance  have been
     authorized for listing,  upon official notice of issuance, on the principal
     securities exchange on which the Common Stock is then listed and traded;

         (iv) the  Computed  Price for the  Payment  Shares is less than the par
     value of the Common Stock;

         (v) an Event of Default has occurred and is continuing;

         (vi) the Common  Stock is neither (i) listed or admitted for trading on
     a national securities exchange nor (ii) quoted on Nasdaq; or

                                        3

<PAGE>


         (vii) the  issuance  of  Payment  Shares  would  result  in the  Holder
     (including all Aggregated  Persons)  beneficially  owning more than 4.9% of
     the Common Stock,  determined as provided in the second sentence of Section
     2.1.

         (c) If the Stock Payment Option is elected, the Company shall issue and
dispatch or cause to be  dispatched to the Holder one or more  certificates  for
the aggregate  number of whole shares of Common Stock determined by dividing the
per share Computed Price of the Common Stock on the applicable  Interest Payment
Date into the total amount of lawful money of the United States of America which
the Holder would receive if the aggregate  amount of interest on this Note which
is being paid in shares of Common  Stock were being paid in such  lawful  money;
provided,  however,  that if in  connection  with any such  election the Company
shall have  failed to notify the  Holder on or before  the  particular  Interest
Payment Date that the Company has elected to use the Stock  Payment  Option with
respect to such Interest  Payment Date or to deliver the  appropriate  number of
shares  of  Common  Stock to the  Holder  within  five  Trading  Days  after the
applicable  Interest Payment Date, then the Company shall not be entitled to use
the Stock  Payment  Option in respect of such Interest  Payment Date,  such cash
interest  shall be  immediately  due and payable  and the Company  shall pay the
interest for such Interest  Payment Date in cash with Default  Interest,  at the
rate  provided in the Note,  from such  Interest  Payment  Date until  paid.  No
fractional  shares will be issued in payment of  interest on this Note.  In lieu
thereof,  the Company  may,  at its  option,  issue a number of shares of Common
Stock which  reflects a rounding  up to the next whole  number or may pay lawful
money of the United  States of America in lieu of  issuance  of such  fractional
share.

         (d) If the Company exercises the Stock Payment Option with respect to a
payment of interest on this Note, the Company shall deliver to the Holder, on or
prior to the date on which  Payment  Shares for such payment of interest on this
Note are to be received by the Holder, a Company  Certificate  setting forth (i)
the total amount of the interest  payment to which the Holder is entitled,  (ii)
the portion of the  interest  payment  being made in Payment  Shares,  (iii) the
number of Payment Shares  allocable to such payment,  as calculated  pursuant to
this Section 1.1,  (iv) any  rounding  adjustment  to such number or any payment
necessary to be made pursuant to Section  1.1(c),  (v) a brief  statement of the
facts requiring such adjustment, (vi) the number of Payment Shares issuable with
respect to each $100 of interest on this Note after such  adjustment and (vii) a
brief  statement  that none of the  conditions  set forth in Section  1.1(b) has
occurred and is existing.  The certificates for the Payment Shares shall be duly
issued  in the name of the  Holder  or its  nominee,  representing  the  Payment
Shares. Such Company Certificate shall be conclusive evidence of the correctness
of the calculation of the number of Payment Shares  allocable to the payments to
which such Company  Certificate  relates and of any  adjustments  to such number
made pursuant to this Section 1.1 in the absence of manifest error. In addition,
on or before the pertinent  payment  date,  the Company shall cause the transfer
agent for the Common  Stock to prepare and issue the  certificates  representing
the Payment Shares in

                                        4

<PAGE>


the name of the Holder  before  being so delivered by the Company on the payment
date.

         (e) The Payment Shares,  when issued pursuant to and in compliance with
this Section 1.1,  shall be, and for all purposes shall be deemed to be, validly
issued,  fully paid and  nonassessable  shares of Common Stock; the issuance and
delivery thereof will in all respects be authorized;  and the issuance  thereof,
together with lawful money of the United States of America, if any, paid in lieu
of fractional  shares of such Common Stock,  will be, and for all purposes shall
be deemed to be, in full discharge and satisfaction of the Company's  obligation
to pay the interest on this Note to which such Payment Shares relate.

         (f) Upon  request of the Company  from time to time,  the Holder  shall
provide information  concerning the number of Payment Shares which may be issued
to the Holder within the limitation provided in Section 1.1(b)(vii).

         1.2 No  Prepayment,  Etc.  This Note may not be  prepaid,  redeemed  or
repurchased at the option of the Company prior to the Maturity Date.


                                   ARTICLE II

                    CONVERSION; CERTAIN MANDATORY REDEMPTION
                             RIGHTS AND OBLIGATIONS

         2.1 Conversion  Right. The Holder shall have the right on and after the
date which is 90 days after the  Issuance  Date to the date this Note is paid in
full,  to  convert  at any  time  all or  from  time  to  time  any  part of the
outstanding  and unpaid  principal  amount of this Note, in each such case of at
least  $10,000,  or such lesser amount as shall remain unpaid at the time of the
conversion or shall be convertible within the limitation on beneficial ownership
provided in the second  sentence of Section 2.1 or may be permitted from time to
time by the Company in its discretion,  and in each such case accrued and unpaid
interest on the  principal  amount to be converted  and Default  Interest on any
such interest,  into fully paid and nonassessable  shares of Common Stock at the
Conversion Price in effect on the date the applicable Conversion Notice is given
in accordance with this Note.  Notwithstanding any other provision of this Note,
in no event  shall the Holder be  entitled at any time to convert any portion of
the principal  amount of this Note (and accrued and unpaid interest  thereon and
Default  Interest  on any  such  interest)  in  excess  of that  portion  of the
principal  amount of this Note (and  accrued  and unpaid  interest  thereon  and
Default  Interest on any such interest) upon  conversion of which the sum of (1)
the number of shares of Common Stock beneficially owned by the Holder (including
shares of Common Stock beneficially owned by all Aggregated Persons) (other than
shares of Common Stock deemed beneficially owned by the Holder or any Aggregated
Person of the Holder through the ownership of (x) the unconverted portion of the
principal

                                        5

<PAGE>


amount of this Note and the Other Notes and accrued and unpaid interest  thereon
and on any such interest and (y) the  unconverted or unexercised  portion of any
instrument  which  contains  limitations  similar  to  those  set  forth in this
sentence) and (2) the number of shares of Common Stock issuable upon  conversion
of the  portion  of the  principal  amount of this Note and  accrued  and unpaid
interest thereon and Default Interest on any such interest with respect to which
the  determination  in this  sentence is being made,  would result in beneficial
ownership  by the Holder and all  Aggregated  Persons of the Holder of more than
4.9% of the outstanding  shares of Common Stock. For purposes of the immediately
preceding sentence,  beneficial ownership shall be determined in accordance with
Section  13(d) of the 1934  Act,  and  Regulation  13D-G  thereunder,  except as
otherwise  provided in clause (1) of the  immediately  preceding  sentence.  For
purposes of the second  preceding  sentence,  the  Company  shall be entitled to
rely,   and  shall  be  fully   protected  in  relying,   on  any  statement  or
representation made by the Holder to the Company in connection with a particular
conversion,  without  any  obligation  on the  part of the  Company  to make any
inquiry  or  investigation  or to  examine  its  records  or the  records of any
transfer  agent for the Common  Stock and without any  liability  of the Company
with  respect  thereto.  The number of shares of Common  Stock to be issued upon
each conversion of this Note shall be determined by dividing the sum of (1) that
portion of the  principal  amount of this Note to be converted  plus (2) accrued
and unpaid interest on such principal  amount to the date the Conversion  Notice
for such  conversion is given plus (3) accrued and unpaid Default  Interest,  if
any, on the amount  referred to in the immediately  preceding  clause (2) to the
date such Conversion  Notice is given, by the Conversion  Price in effect on the
date the Conversion Notice for such conversion is given.

         2.2 Authorized  Shares.  The Company  covenants that, during the period
the  conversion  rights exist,  the Company will reserve from its authorized and
unissued Common Stock [INSERT THE LESSER OF 20% OF THE OUTSTANDING  COMMON STOCK
AND 125% OF THE AGGREGATE NUMBER OF SHARES ISSUABLE UPON CONVERSION OF THIS NOTE
AND THE OTHER NOTES AT THE AVERAGE OF TWO LOWEST  TRADING  PRICES  DURING THE 20
TRADING DAYS PRIOR TO DATE THE NOTE PURCHASE AGREEMENT IS SIGNED] shares,  (such
amount  to be  subject  to  equitable  adjustment  from  time to  time on  terms
reasonably   acceptable  to  the  Holder  for  stock  splits,  stock  dividends,
combinations,  capital reorganizations and similar events relating to the Common
Stock  occurring on or after the  Issuance  Date) to provide for the issuance of
Common  Stock  upon the  conversion  in full of this Note and the  Other  Notes,
subject to  reduction  from time to time by the number of shares of Common Stock
issued on conversion of this Note and the Other Notes.  The Company shall,  from
time to time,  authorize  and reserve  additional  shares of Common  Stock to be
issuable pursuant to the terms of this Note as shall be necessary to ensure that
an adequate  number of shares of Common  Stock are at all times  authorized  and
reserved for issuance  upon  conversion in full of this Note and the Other Notes
and the payment of interest on this Note in  accordance  with Section 1.1 and on
the Other Notes

                                        6

<PAGE>


in  accordance  with the terms  thereof.  The  Company  shall  notify the Holder
promptly,  but in no event more than ten  Business  Days,  after the  Company so
reserves  additional  shares of Common  Stock,  which notice shall set forth the
number of additional shares of Common Stock so reserved.  The Company represents
and warrants  that upon  issuance,  such shares of Common Stock will be duly and
validly  issued,  fully paid and  non-assessable.  The  Company  agrees that its
issuance of this Note shall constitute full authority to its officers and agents
who are charged with the duty of  executing  stock  certificates  to execute and
issue the necessary  certificates for shares of Common Stock upon the conversion
of and payment of interest on this Note.

         2.3 Method of Conversion.

         (a) The right of the Holder to convert  this Note shall be exercised by
delivering  (which may be made by telephone line facsimile  transmission) to the
Company and the Issuing  Agent at the  addresses  or  telephone  line  facsimile
transmission numbers provided in or pursuant to the Transfer Agent Agreement,  a
Conversion Notice stating the principal amount of this Note which, together with
interest  and Default  Interest,  if any,  as  provided  in this Note,  is being
converted  and the  number  of shares  of  Common  Stock to be issued  upon such
conversion.  The Holder shall make reasonable  efforts to deliver a copy of such
Conversion  Notice to the Company's  legal counsel when such notice is delivered
to the  Company  and the  Issuing  Agent  or as soon  as  practical  thereafter,
provided  that the failure to do so shall not relieve the Company or the Issuing
Agent of its obligations or prejudice the Holder's rights.  The number of shares
of Common  Stock to be issued  upon each  conversion  of this Note  shall be the
number set forth in the  applicable  Conversion  Notice,  which  number shall be
conclusive  absent  manifest  error.  The Company shall notify the Holder of any
claim by the Company of manifest error in a Conversion Notice within two Trading
Days after the Holder  gives such  Conversion  Notice and no such claim of error
shall limit or delay performance of the Company's  obligation to issue upon such
conversion  the number of shares of Common  Stock  which are not in  dispute.  A
Conversion  Notice  shall be deemed for all purposes to be in proper form unless
the Company notifies the Holder by telephone line facsimile  transmission within
two Trading Days after a Conversion Notice has been given (which notice from the
Company shall specify all defects in the  Conversion  Notice) and any Conversion
Notice  containing  any such defect shall  nonetheless  be effective on the date
given if the Holder promptly  undertakes in writing to correct all such defects.
The Company shall not be required to pay any tax which may be payable in respect
of any transfer  involved in the issuance and delivery of shares of Common Stock
or other  securities or property on conversion of this Note in a name other than
that of the Holder,  and the  Company  shall not be required to issue or deliver
any such shares or other  securities or property  unless and until the person or
persons  requesting  the  issuance  thereof  shall have paid to the  Company the
amount of any such tax or shall  have  established  to the  satisfaction  of the
Company  that such tax has been paid.  The Holder shall be  responsible  for the
amount of any  withholding tax payable in connection with any conversion of this
Note.

                                        7

<PAGE>


         (b) If the  Holder  elects  to  convert  this Note in  accordance  with
Section 2.1, the Holder shall not be required to surrender this Note  physically
unless the entire  unpaid  principal  amount of this Note is so  converted.  The
Company shall maintain records showing the principal amount so converted and the
dates  of  such   conversions  or  shall  use  such  other  method,   reasonably
satisfactory to the Holder, so as not to require physical surrender of this Note
upon each such  conversion.  In the event of any  dispute or  discrepancy,  such
records of the Company shall be controlling and  determinative in the absence of
manifest error.  Notwithstanding  the foregoing,  if any portion of this Note is
converted  without physical  surrender of this Note to the Company as aforesaid,
the Holder may not  transfer  this Note unless (1) the Holder  first  physically
surrenders this Note to the Company,  whereupon the Company will forthwith issue
and deliver upon the order of the Holder a new note of like tenor, registered as
the Holder (upon  payment by the Holder of any  applicable  transfer  taxes) may
request,  representing in the aggregate the remaining unpaid principal amount of
this Note and (2) such  transfer is  otherwise  in  compliance  with Section 8.7
hereof.  The Company  may by notice to the Holder from time to time  require the
Holder to  surrender  this Note in exchange for the issuance by the Company of a
new Note in a principal amount equal to the outstanding principal amount of this
Note and otherwise  having terms  identical to this Note. Such new Note shall be
delivered  by the  Company to the Holder  within  three  Trading  Days after the
Company  receives  this Note from the Holder in  response  to such  notice.  The
Holder and any assignee, by acceptance of this Note, acknowledge and agree that,
by reason of the provisions of this paragraph, following conversion of a portion
of this  Note,  the  unpaid  and  unconverted  principal  amount  of  this  Note
represented by this Note may be less than the amount stated on the face hereof.

         (c) In case of any  consolidation  or  merger of the  Company  with any
other corporation (other than a wholly-owned subsidiary of the Company) in which
the Company is not the surviving corporation, or in case of any sale or transfer
of all or substantially all of the assets of the Company,  or in the case of any
share exchange  pursuant to which all of the outstanding  shares of Common Stock
are  converted  into  other  securities  or  property,  the  Company  shall make
appropriate  provision  or cause  appropriate  provision  to be made so that the
Holder  shall have the right  thereafter  to convert  this Note into the kind of
shares  of  stock  and  other  securities  and  property  receivable  upon  such
consolidation,  merger, sale, transfer or share exchange by the persons who were
holders  of  Common  Stock  immediately  prior  to the  effective  date  of such
consolidation,  merger,  sale,  transfer or share  exchange and on a basis which
preserves  the  economic  benefits of the  conversion  rights of the Holder on a
basis as nearly as practical as such rights existed prior to such consolidation,
merger,  sale,  transfer  or share  exchange.  If, in  connection  with any such
consolidation, merger, sale, transfer or share exchange each holder of shares of
Common Stock is entitled to elect to receive  either  securities,  cash or other
assets upon completion of such  transaction,  the Company shall provide or cause
to be  provided to the Holder the right to elect the  securities,  cash or other
assets into which this Note shall be  convertible  after  completion of any such
transaction on the same terms and subject

                                        8

<PAGE>


to the same  conditions  applicable  to holders of the Common Stock  (including,
without limitation,  notice of the right to elect,  limitations on the period in
which such  election  shall be made,  and the effect of failing to exercise  the
election).  Notwithstanding  the foregoing,  in connection with any such merger,
consolidation,  sale, transfer or exchange, the Company shall have the right, in
lieu of making  provision  for  preservation  of the  economic  benefits  of the
conversion  rights  of  the  Holder,  to  redeem  this  Note  immediately  after
completion of such transaction at a redemption price equal to the sum of (1) the
product  obtained by multiplying  (A) the sum of (i) the  outstanding  principal
amount of this Note on the date of such  redemption plus (ii) accrued and unpaid
interest on such principal  amount to the date of such redemption  times (B) the
applicable  Business  Combination  Redemption  Percentage  plus (2)  accrued and
unpaid Default  Interest,  if any, on the amount  referred to in the immediately
preceding  clause  (1)(A)(ii)  at the rate  provided in this Note to the date of
such redemption. Such right shall be exercised by notice from the Company to the
Holder stating that the Company is exercising  its  redemption  right under this
Section  2.3(c),  which  notice shall be given at least 20 Trading Days (or such
lesser period as the Company gives notice of such  transaction to the holders of
outstanding shares of Common Stock) prior to completion of such transaction. The
Company  shall not effect any such  transaction  unless the  provisions  of this
paragraph have been complied with. The above provisions shall similarly apply to
successive consolidations, mergers, sales, transfers or share exchanges.

         Whenever the Company shall propose to take any of the actions specified
in this  Section  2.3(c),  the Company  shall cause a notice to be mailed to the
Holder at least 15 days prior to the date on which the books of the Company will
close or on which a record  will be taken for such  action.  Such  notice  shall
specify the action  proposed to be taken by the Company and the date as of which
holders of record of the Common Stock shall  participate  in any such actions or
be entitled to exchange their Common Stock for securities or other property,  as
the case may be.

         (d) Upon  receipt by the Company and the Issuing  Agent from the Holder
of a Conversion  Notice meeting the  requirements  for conversion as provided in
Section 2.1 and this Section  2.3, the Company  shall issue and deliver or cause
to be issued and  delivered  to the  Holder  certificates  for the Common  Stock
issuable upon such  conversion by the close of business on the third Trading Day
after the date of such  receipt,  and as of the close of business on the date of
receipt of such Conversion Notice the Holder shall be deemed to be the holder of
record of the  Common  Stock  issuable  upon such  conversion,  the  outstanding
principal  amount  and the amount of accrued  and unpaid  interest  on this Note
shall be reduced to reflect such conversion,  and all rights with respect to the
portion of this Note being so converted  shall  forthwith  terminate  except the
right to receive the Common Stock or other securities,  cash or other assets, as
herein provided,  on such conversion.  The Holder shall also give a copy of each
Conversion  Notice to the Company's  legal counsel,  as specified in the form of
Conversion Notice, but the

                                        9

<PAGE>


failure  to give such copy  shall not  affect  the  validity  of any  Conversion
Notice.  If the Holder shall have given a Conversion  Notice in accordance  with
the terms of this  Note,  the  Company's  obligation  to issue and  deliver  the
certificates for Common Stock shall be absolute and unconditional,  irrespective
of any  action or  inaction  by the Holder to  enforce  the same,  any waiver or
consent  with  respect to any  provision  thereof,  the recovery of any judgment
against  any person or any action to enforce  the same,  any failure or delay in
the  enforcement  of any other  obligation of the Company to the Holder,  or any
setoff,  counterclaim,  recoupment,  limitation or termination, or any breach or
alleged  breach  by the  Holder or any other  person  of any  obligation  to the
Company or any violation or alleged  violation of law by the Holder or any other
person,  and irrespective of any other  circumstance which might otherwise limit
such obligation of the Company to the Holder in connection with such conversion;
provided, however, that nothing herein shall limit or prejudice the right of the
Company to pursue any such claim in any other  manner  permitted  by  applicable
law. The  occurrence of an event which  requires an equitable  adjustment of the
Trading Price as contemplated by the definition  thereof in Section 7.1 shall in
no way  restrict  or delay the right of the Holder to receive  certificates  for
Common  Stock upon  conversion  of this Note and the Company  shall use its best
efforts to implement  such  adjustment  on terms  reasonably  acceptable  to the
Holder  within two Business  Days of such  occurrence.  If the Company  fails to
issue and deliver the  certificates  for the Common Stock to the Holder pursuant
to the first  sentence of this Section  2.3(d) as and when required to do so, in
addition  to any other  liabilities  the Company  may have  hereunder  and under
applicable  law, (1) the Company shall pay or reimburse the Holder on demand for
all out-of-pocket expenses including,  without limitation,  fees and expenses of
legal  counsel  incurred  by the  Holder  as a result of such  failure,  (2) the
Conversion  Price applicable to such conversion shall be reduced by one-tenth of
one percent of the amount thereof  otherwise  applicable to such  conversion for
each  Trading Day during the period  from the date the  Company was  required to
deliver such certificates to the date the Company so delivers such certificates;
provided,  however,  that in no event shall any such  reduction  be made for any
Trading Day in such  period  which is after the date which is 120 days after the
date the Company was required to deliver such  certificates  in connection  with
such conversion, and (3) the Holder may by written notice (which may be given by
mail,  courier,  personal  service or telephone line facsimile  transmission) or
oral notice (promptly  confirmed in writing) given at any time prior to delivery
to the Holder of the  certificates  for the shares of Common Stock issuable upon
such  conversion  of this Note,  rescind such  conversion,  whereupon the Holder
shall have the right to convert this Note  thereafter  in  accordance  herewith;
provided,  however, that the Company shall not be liable to the Holder under the
preceding  clause (1) or clause (2) to the extent the  failure of the Company to
deliver or cause to be delivered  such shares of Common Stock results from fire,
flood,  storm,  earthquake,  shipwreck,  strike,  war, acts of terrorism,  crash
involving  facilities  of a  common  carrier,  act of God or any  similar  event
outside  the control of the  Company  (it being  understood  that the actions or
failure to act of the  Issuing  Agent  shall not be deemed an event  outside the
control of the Company except to the extent resulting from fire,  flood,  storm,
earthquake,

                                       10

<PAGE>


shipwreck,  strike,  war, acts of  terrorism,  crash  involving  facilities of a
common carrier,  acts of God, the bankruptcy,  liquidation or  reorganization of
the Issuing Agent under any  bankruptcy,  insolvency or other similar law or any
similar event outside the control of the Issuing Agent). The Holder shall notify
the Company in writing (or by telephone  conversation,  confirmed in writing) as
promptly as practicable  after becoming aware that shares of Common Stock issued
on  conversion  of this Note have not been  received as provided in this Section
2.3(d).

         (e)  No  fractional  shares  of  Common  Stock  shall  be  issued  upon
conversion  of this Note but, in lieu of any fraction of a share of Common Stock
which would  otherwise  be issuable in respect of the  aggregate  number of such
shares  converted  at one time by the same  holder,  the  Company  may round the
number  of  shares of Common  Stock  issued  on such  conversion  up to the next
highest  whole share or may pay lawful money of the United States of America for
such fractional share, based on a value of one share of Common Stock being equal
to the Market  Price of the Common Stock on the date the  applicable  Conversion
Notice is given to the Company, as reported by Bloomberg, L.P.

         2.4 Limitation on Shares Issuable on Conversion; Mandatory Redemption.

         (a) Notwithstanding any other provision herein,  unless the Stockholder
Approval shall have been obtained from the stockholders of the Company or waived
by Nasdaq,  the Company  shall not be required to issue upon  conversion of this
Note a number of shares of Common  Stock in excess of the Maximum  Share  Amount
less the number of shares of Common  Stock  issued  pursuant to Section 1.1 from
time to time in payment of interest on this Note.  The  Company  shall  maintain
records  which show the number of shares of Common  Stock  issued by the Company
upon  conversion  from  time to time of this  Note  and  issued  by the  Company
pursuant to Section 1.1 in payment of interest on this Note, which records shall
be controlling in the absence of manifest error. Upon surrender of this Note for
transfer  or  re-registration  hereof  (or,  at the  option of the  Holder,  for
conversion  pursuant to Section 2.1 of less than all of this Note),  the Company
shall  make  a  notation  on  the  new  Note   issued  upon  such   transfer  or
re-registration or evidencing such unconverted portion of this Note, as the case
may be, as to the  remaining  number of shares of Common  Stock from the Maximum
Share Amount  remaining  available for  conversion of the Note evidenced by such
new  certificate  (including,  without  limitation,  by taking into  account the
number of shares of Common Stock  issued by the Company  pursuant to Section 1.1
in payment of interest on this Note and not previously  reflected on the Note so
surrendered, as shown on the records maintained by the Company). If this Note is
surrendered  for  split-up  into two or more  Notes  representing  an  aggregate
principal  amount  equal to the  principal  amount  of this  Note at the time so
surrendered (as reduced by any  contemporaneous  conversion of this Note),  each
Note issued on such split-up shall bear a notation of the portion of the Maximum
Share Amount allocated thereto  determined by pro rata allocation from among the
remaining portion of the Maximum Share Amount

                                       11

<PAGE>


allocated  to  this  Note at the  time  so  surrendered.  If any  Other  Note is
converted in full,  repaid,  repurchased or redeemed,  all of the portion of the
Maximum  Share  Amount (as defined in such Other Note)  allocated  to such Other
Note which remains  unissued  after such  conversion,  repayment,  repurchase or
redemption shall be re-allocated to this Note and the Other Notes outstanding at
the close of business on the date of such conversion,  repayment,  repurchase or
redemption of the Other Note so converted,  repaid,  repurchased or redeemed pro
rata based on the principal amounts outstanding at the close of business on such
date.

         (b) (1) If a Maximum Share Amount  Inconvertibility  or a  Registration
Restriction  Inconvertibility occurs, then the Company shall promptly, but in no
event  later  than three  Business  Days  after  each such  occurrence,  give an
Inconvertibility  Notice to the Holder (by telephone line facsimile transmission
at such  number as the Holder has  specified  in writing to the Company for such
purposes  or,  if the  Holder  shall  not have  specified  any such  number,  by
overnight courier or first class mail, postage prepaid,  at the Holder's address
as the same  appears on the  records of the  Company)  and the Holder may at any
time after such occurrence give an  Inconvertibility  Notice to the Company.  If
the  Company  shall have  given or been  required  to give any  Inconvertibility
Notice,  or if the Holder  shall have given any  Inconvertibility  Notice,  then
within the applicable Redemption Election Period the Holder shall have the right
by a  Redemption  Election  given to the Company  (which may be contained in the
Inconvertibility Notice given by the Holder) to direct the Company to redeem the
portion of this Note (which, if applicable,  shall be all of this Note) as shall
not,  on the  Business  Day  prior to the  applicable  Redemption  Date,  (x) be
convertible  into  shares of Common  Stock by reason of a Maximum  Share  Amount
Inconvertibility  or (y) be  available  for sale by the Holder  pursuant  to the
Registration Statement by reason of a Registration Restriction Inconvertibility,
in each such case, on the  applicable  Redemption  Date, at a price equal to the
Redemption Price;  provided,  however, that (1) no such redemption shall be made
with respect to a  Registration  Restriction  Inconvertibility  if, prior to the
expiration of the applicable  Redemption  Election  Period,  the Company and the
Holder shall, by a Mandatory  Redemption Waiver,  waive the Company's obligation
to make such redemption and (2) no such redemption shall be made with respect to
a Registration Restriction Inconvertibility if (i) the Registration Statement is
effective and available for use by the Holder for resale of the shares of Common
Stock which are covered by the  Registration  Statement,  (ii) the Company files
with an  additional  Registration  Statement  as and when  required  by  Section
8(b)(1) and (iii) the Company maintains Net Cash, Cash Equivalent and Short-Term
Investment  Balances  of at least  $15,000,000,  then the  Company  shall not be
required  to redeem any  portion of this Note prior to the date which is 30 days
after such Registration Restriction Inconvertibility occurs. If the Holder gives
a  Redemption  Election  to the  Company  by reason of a  Maximum  Share  Amount
Inconvertibility  and,  prior to the date the Company is required to redeem this
Note or any  portion  hereof,  the  Company  would  have been  able,  within the
limitations set forth in Section 2.4(a), to convert all of this Note (determined
without regard to the  limitation,  if any,  contained in the second sentence of
Section 2.1 and

                                       12

<PAGE>


regardless of whether this Note is, by its terms,  convertible  at such time) on
any two  Trading  Days  within  any  period of three  consecutive  Trading  Days
commencing  after the period of ten consecutive  Trading Days which gave rise to
the applicable  Inconvertibility  Notice from the Company or the Holder,  as the
case may be, had the Holder given a Conversion  Notice for conversion in full of
this Note on each of such two Trading Days within such three-Trading Day period,
then the  Company  shall not be required to redeem any of this Note by reason of
such Redemption Election.

         (2) An  Inconvertibility  Notice or a Redemption  Election given by the
Holder  shall be deemed for all purposes to be in proper form unless the Company
notifies   the  Holder  in  writing   within  three   Business   Days  after  an
Inconvertibility  Notice or a Redemption  Election has been given (which  notice
shall  specify  all  defects  in  the  Inconvertibility   Notice  or  Redemption
Election), and any Inconvertibility Notice or Redemption Election containing any
such  defect  shall  nonetheless  be  effective  on the date given if the Holder
promptly  undertakes in writing to correct all such  defects.  In the absence of
any such  undertaking  from the  Holder,  no such claim of error  shall limit or
delay  performance of the Company's  obligation to redeem the full amount of the
Inconvertible Portion as to which a Redemption Election has been given and which
is not in dispute.

         (c)  Notwithstanding the giving of any  Inconvertibility  Notice by the
Company  to the  Holder or the  giving or the  absence  of any  Inconvertibility
Notice  or  Redemption   Election  by  the  Holders  or  any  redemption  of  an
Inconvertible  Portion  pursuant to Section 2.4(b),  thereafter the provision of
Section  2.4(b) shall continue to be applicable on any occasion  unless,  in the
case of a Maximum Share Amount Inconvertibility,  the Stockholder Approval shall
have been obtained or waived by the Nasdaq.

         (d) On  each  Redemption  Date,  the  Company  shall  make  payment  in
immediately  available funds of the applicable  Redemption  Price to or upon the
order of the Holder as  specified  by the  Holder in  writing to the  Company at
least one Business Day prior to such Redemption Date. If the Company is required
to redeem any  Inconvertible  Portion  pursuant to this Section 2.4, the Company
shall make  payment to the Holder of an amount  equal to the  Redemption  Price.
Upon redemption of less than all of this Note,  promptly,  but in no event later
than  three  Business  Days after  surrender  of this Note to the  Company,  the
Company shall issue a replacement  Note of like tenor having a principal  amount
equal to the principal amount of this Note remaining after such redemption.

         (e) If the  Company  shall  have  failed to pay in full the  Redemption
Price (other than by reason of a Maximum Share Amount  Inconvertibility)  or the
Registration  Redemption Price when the same is due and payable,  without in any
way relieving the Company of its obligation to pay such amount, the Holder shall
have the right to convert into Common Stock

                                       13

<PAGE>


the  portion of this Note in respect  of which  such  payment  was not made into
Common Stock in  accordance  with Section 2.1  (subject to the  numerical  limit
contained in the second sentence of Section 2.1);  provided,  however,  that the
shares of Common  Stock  received  by the  Holder  upon any such  conversion  in
certain  circumstances  may be subject to  restrictions  on resale by the Holder
arising under applicable securities laws to the extent not registered for resale
by the Holder pursuant to the Registration Statement.

         (f) If the  Company  shall  have  failed to pay in full the  Redemption
Price for any portion (which,  if applicable,  may be all) of any  Inconvertible
Portion  when the same is due and  payable by reason of a Maximum  Share  Amount
Inconvertibility  and the  Stockholder  Approval  shall not have been  obtained,
without in any way relieving the Company of its obligation to pay such amount in
accordance  with  Sections  2.4(b) and 2.4(d),  upon the written  request of the
Majority Holders, the Company shall use its commercially reasonable best efforts
to obtain a waiver from the NASD of the requirement for Stockholder Approval for
issuance of all shares of Common Stock issuable upon conversion of this Note and
the  Other  Notes.  If such a waiver,  in form  reasonably  satisfactory  to the
Majority Holders,  is not obtained within 15 days after the Company's receipt of
such  request  from the  Majority  Holders,  the Company  promptly  shall call a
special meeting of its stockholders, to be held not later than 60 days after the
expiration of the foregoing 15-day period, to seek the Stockholder  Approval for
issuance of all shares of Common Stock issuable upon conversion of this Note and
the Other Notes in accordance with Section 2.1.

         (g) If the Holder  converts all or any portion of this Note pursuant to
Section  2.4(e),  the  amount  of  the  Redemption  Price  or  the  Registration
Redemption  Price,  as the case may be,  due to the Holder  with  respect to the
portion of this Note so converted  shall be reduced by the  principal  amount of
this Note so converted  and the Company  shall remain  liable for payment of the
premium,  if any,  included in such Redemption Price or Registration  Repurchase
Price, as the case may be.


                                   ARTICLE III

                                CERTAIN COVENANTS

         So long as at least $1,500,000  aggregate principal amount of this Note
and the Other Notes remains outstanding:

         3.1 Limitations on Certain  Indebtedness.  The Company will not itself,
and will not permit any Subsidiary to,  create,  assume,  incur or in any manner
become liable in respect of,  including,  without  limitation,  by reason of any
business combination transaction (all

                                       14

<PAGE>


of which are referred to herein as  "incurring"),  any  Indebtedness  other than
Permitted Indebtedness.

         3.2 Tender Offers. The Company will not itself, and will not permit any
Subsidiary to (1) make any Tender Offer for  outstanding  shares of Common Stock
unless the Company contemporaneously therewith makes an offer, or (2) enter into
an agreement  regarding a Tender Offer for outstanding shares of Common Stock by
any person other than the Company or any  Subsidiary,  unless such person agrees
with the  Company  to make an  offer,  in either  such  case,  to the  Holder to
purchase the same  percentage of the outstanding  principal  amount of this Note
held by the  Holder as the  percentage  of  outstanding  shares of Common  Stock
offered to be purchased in such Tender Offer, at a price equal to the greater of
(i) an amount equal to the sum of (1) the sum of (A) the  outstanding  principal
amount of this Note plus (B)  accrued  and  unpaid  interest  on such  principal
amount to the date of payment plus (C) accrued and unpaid Default  Interest,  if
any, on the amount  referred to in the immediately  preceding  clause (B) at the
rate provided in this Note to the date of purchase pursuant to such Tender Offer
plus (2) an amount equal to the product  obtained by multiplying  (a) the sum of
the amounts stated in the immediately  preceding clauses (1)(A) and (1)(B) times
(b) either (I) if the date of purchase  pursuant  to such Tender  Offer is on or
before the date which is 120 days after the Issuance  Date,  12.5%,  (II) if the
date of purchase  pursuant to such Tender Offer is on or after the date which is
121 days  after the  Issuance  Date and on or before  the date which is 270 days
after the Issuance Date,  15.0%,  and (III) if the date of purchase  pursuant to
such Tender  Offer is on or after the 271st day after the Issuance  Date,  20.0%
and (ii) an amount equal to the product  obtained by multiplying  (x) the number
of shares of Common  Stock which would,  but for the  purchase  pursuant to such
Tender Offer,  be issuable on  conversion in accordance  with Section 2.1 of the
portion of this Note tendered by the Holder and any accrued and unpaid  interest
thereon and any accrued and unpaid Default Interest if a Conversion  Notice were
given by the  Holder  on the date of  purchase  pursuant  to such  Tender  Offer
(determined  without  regard to any  limitation on  conversion  contained in the
second  sentence of Section 2.1) times (y) the highest price per share of Common
Stock paid or payable pursuant to such Tender Offer.

         3.3 Payment of  Obligations.  The Company will pay and  discharge,  and
will  cause  each  Significant  Subsidiary  to  pay  and  discharge,  all  their
respective material obligations and liabilities,  including, without limitation,
tax  liabilities,  except  where  the same  may be  contested  in good  faith by
appropriate proceedings.

         3.4 Maintenance of Property; Insurance.

         (a) The Company will keep, and will cause each  Significant  Subsidiary
to keep, all property useful and necessary in its business in good working order
and condition, ordinary wear and tear excepted.

                                       15

<PAGE>


         (b)  The  Company  will  maintain,  and  will  cause  each  Significant
Subsidiary  to  maintain,  with  financially  sound  and  responsible  insurance
companies,  insurance  in at least such  amounts  and  against  such risks as is
reasonably adequate for the conduct of their respective businesses and the value
of their respective properties.

         3.5 Conduct of Business and Maintenance of Existence.  The Company will
continue,  and will cause each Subsidiary to continue,  to engage in business of
the same general type as now conducted by the Company, and will preserve,  renew
and keep in full force and effect, and will cause each Significant Subsidiary to
preserve,  renew and keep in full force and effect  their  respective  corporate
existence and their respective  rights,  privileges and franchises  necessary or
desirable in the normal conduct of business.

         3.6 Compliance with Laws. The Company will comply,  and will cause each
Significant  Subsidiary to comply,  in all material respects with all applicable
laws,  ordinances,  rules,  regulations,  decisions,  orders and requirements of
governmental   authorities   and   courts   (including,    without   limitation,
environmental  laws) except (i) where compliance  therewith is contested in good
faith by appropriate  proceedings or (ii) where  non-compliance  therewith could
not  reasonably be expected to have a material  adverse  effect on the business,
condition  (financial  or  otherwise),  operations,  performance,  properties or
prospects of the Company and its subsidiaries taken as a whole.

         3.7  Investment  Company  Act.  The  Company  will not be or  become an
open-end  investment  trust,  unit investment  trust or face-amount  certificate
company  that  is or is  required  to  be  registered  under  Section  8 of  the
Investment Company Act of 1940, as amended.


                                   ARTICLE IV

                                EVENTS OF DEFAULT

         If any of the following events of default (each, an "Event of Default")
shall occur:

         4.1 Failure to Pay Principal or Interest.  The Company fails (a) to pay
the principal,  Redemption  Price,  Repurchase Price or Registration  Repurchase
Price hereof when due, whether at maturity,  upon redemption,  upon acceleration
or otherwise,  as applicable,  or (b) to pay any  installment of interest hereon
when due and,  in the case of this  clause (b) of this  Section  4.1 only,  such
failure continues for a period of five Business Days after the due date thereof;
or

                                       16

<PAGE>


         4.2 Conversion  and the Shares.  The Company fails to issue or cause to
be issued  shares of Common  Stock to the Holder upon  exercise by the Holder of
the conversion rights of the Holder in accordance with the terms of this Note or
upon exercise of the Warrants or fails to transfer any certificate for shares of
Common Stock issued to the Holder upon  conversion of this Note or in payment of
interest on this Note or upon  exercise of the Warrants as and when  required by
this Note, the Note Purchase  Agreement,  the Transfer  Agent  Agreement and the
Warrants; or

         4.3 Breach of  Covenant.  The Company (a) fails to comply with  Section
3.1 or 3.2 or (b) fails to comply in any material  respect with any provision of
Article III of this Note (other than  Section 3.1 or 3.2) or breaches  any other
material  covenant or other  material term or condition of this Note (other than
as  specifically  provided in Sections  4.1,  4.2,  4.3(a)),  the Note  Purchase
Agreement, the Transfer Agent Agreement or the Warrants, and in the case of this
clause (b) of this  Section  4.3 only,  such  breach  continues  for a period of
fifteen (15) days after written notice thereof to the Company from the Holder or
within 30 days after  delivery of such  notice if, and only if, such  default is
reasonably  capable of cure  within 30 days  after such  notice and at all times
during such 30-day period the Company has been diligently  taking action to cure
such default and such cure cannot be completed within such 15-day period; or

         4.4   Breach  of   Representations   and   Warranties.   Any   material
representation  or  warranty of the  Company  made  herein or in any  agreement,
statement  or  certificate  given in writing  pursuant  hereto or in  connection
herewith  (including,  without  limitation,  the Note  Purchase  Agreement,  the
Transfer Agent  Agreement and the Warrants)  shall be false or misleading in any
material respect when made; or

         4.5  Certain  Voluntary  Proceedings.  The  Company or any  Significant
Subsidiary  shall  commence  a  voluntary  case  or  other  proceeding   seeking
liquidation,  reorganization or other relief with respect to itself or its debts
under any bankruptcy, insolvency or other similar law now or hereafter in effect
or seeking the  appointment  of a trustee,  receiver,  liquidator,  custodian or
other similar official of it or any substantial  part of its property,  or shall
consent to any such relief or to the appointment of or taking  possession by any
such official in an involuntary case or other proceeding  commenced  against it,
or shall make a general  assignment for the benefit of creditors,  or shall fail
generally  to pay its debts as they  become due or shall  admit in  writing  its
inability generally to pay its debts as they become due; or

         4.6  Certain  Involuntary  Proceedings.  An  involuntary  case or other
proceeding shall be commenced against the Company or any Significant  Subsidiary
seeking  liquidation,  reorganization  or other relief with respect to it or its
debts under any bankruptcy,  insolvency or other similar law now or hereafter in
effect or seeking the appointment of a trustee, receiver, liquidator,  custodian
or other similar official of it or any substantial part of its

                                       17

<PAGE>


property, and such involuntary case or other proceeding shall remain undismissed
and unstayed for a period of sixty (60) consecutive days; or

         4.7 Judgments.  Any court of competent  jurisdiction shall enter one or
more final  judgments  against  the  Company or any  Subsidiary  or any of their
respective  properties  or other  assets  in an  aggregate  amount  in excess of
$750,000, which is not vacated, bonded, stayed, discharged,  satisfied or waived
for a period of thirty (30) consecutive days; or

         4.8 Default Under Other  Agreements.  (a) The Company or any Subsidiary
shall (i) default in any payment with respect to any  indebtedness  for borrowed
money (other than this Note) which  indebtedness  has an  outstanding  principal
amount in excess of $1,000,000  individually  or $2,500,000 in the aggregate for
the Company and its  Subsidiaries,  beyond the period of grace, if any, provided
in the instrument or agreement under which such indebtedness was created or (ii)
default in the observance or performance of any agreement, covenant or condition
relating to any such  indebtedness  or contained in any  instrument or agreement
evidencing,  securing  or  relating  thereto,  or any other event shall occur or
condition  exist,  the effect of which default or other event or condition is to
cause, or to permit the holder or holders of such  indebtedness (or a trustee or
agent on behalf of such holder or holders) to cause,  any such  indebtedness  to
become due prior to its stated maturity and such default or event shall continue
beyond the period of grace,  if any,  provided in the  instrument  or  agreement
under which such indebtedness was created (after giving effect to any consent or
waiver  obtained and then in effect  thereunder);  provided,  however,  that the
events and conditions  described in the preceding clauses (i) and (ii) shall not
constitute  an Event of Default  unless and until the Company  fails to take the
action  necessary to correct  such event or  condition  within five (5) Business
Days of becoming aware of such event or condition;  or (b) any  indebtedness  of
the Company or any of its Subsidiaries which has an outstanding principal amount
in excess of $1,500,000  individually  or $3,500,000 in the aggregate  shall, in
accordance with its terms, be declared to be due and payable,  or required to be
prepaid  other than by a regularly  scheduled or required  payment  prior to the
stated  maturity  thereof;  provided,  however,  that  the  acceleration  of any
indebtedness as a result of the Company's relocation from its current facilities
shall not constitute an Event of Default unless and until an event of default is
declared under the  instrument or agreement  under which such  indebtedness  was
created and such default is not cured by the Company  within five  Business Days
of receipt of notice of such event of default; or

         4.9  Delisting  of Common  Stock.  The Common  Stock  shall cease to be
listed on any of Nasdaq,  the NYSE or the AMEX and shall  remain  unlisted for a
period of three (3) days;

then,  (X) upon the  occurrence  and  during  the  continuation  of any Event of
Default specified in

                                       18

<PAGE>


Section 4.1,  4.2,  4.3,  4.4,  4.7, 4.8, or 4.9 at the option of the Holder the
Company  shall,  and upon the  occurrence  of any Event of Default  specified in
Section 4.5 or 4.6, the Company shall,  pay to the Holder an amount equal to the
sum of  (1)  the  product  obtained  by  multiplying  (a)  the  sum  of (A)  the
outstanding  principal  amount of this Note plus (B) accrued and unpaid interest
on such  principal  amount  to the  date of  payment  times  (b) the  applicable
Acceleration Percentage plus (2) accrued and unpaid Default Interest, if any, on
the  amount  referred  to in the  immediately  preceding  clause (B) at the rate
provided in this Note to the date of payment,  and (Y) all other amounts payable
hereunder  shall  immediately  become  due  and  payable,  all  without  demand,
presentment or notice,  all of which hereby are expressly waived,  together with
all costs, including, without limitation, reasonable legal fees and expenses, of
collection,  and (Z) the Holder  shall be entitled to exercise  all other rights
and  remedies  available  at law or in  equity;  provided,  however,  that if in
connection  with any Event of Default the  Company  shall not at such time be in
compliance with Section  2.3(c),  then in lieu of payment of the amount provided
in the preceding  clause (X) the Company shall pay to the Holder an amount equal
to the amount which would be payable by the Company upon redemption of this Note
in accordance  with Section  2.3(c) as if the Company had exercised its right to
redeem this Note pursuant to Section 2.3(c) on the date of such payment pursuant
hereto.


                                    ARTICLE V

                      REPURCHASE UPON A REPURCHASE EVENT OR
                          REGISTRATION REPURCHASE EVENT

         5.1  Repurchase  Right Upon  Repurchase  Event.  If there shall occur a
Repurchase  Event, then the Holder shall have the right, at the Holder's option,
to require the Company to repurchase all of this Note, or any portion hereof (in
a minimum  principal amount of $100,000 or integral  multiples  thereof (or such
lesser remaining principal amount of this Note)), on the repurchase date that is
five Business Days after the date of the Holder Notice delivered with respect to
such Repurchase Event. The Holder shall have the right to require the Company to
repurchase all or any such portion of this Note if a Repurchase  Event occurs at
any time while any portion of the principal  amount of this Note is  outstanding
at a price equal to the Repurchase Price; provided,  however, that if such right
to require  repurchase of this Note arises in connection with a transaction that
(i) is intended to qualify as a pooling of interests under the Pooling Standards
and (ii) but for the exercise of  repurchase  rights  under  Section 5.1 of this
Note and Section 5.1 of the Other  Notes,  may qualify as a pooling of interests
under the Pooling Standards, then the Company may, in the reasonable exercise of
its  discretion,  elect not to repurchase  such Note in order to comply with the
Pooling Standards.

                                       19

<PAGE>


         5.2 Notices; Method of Exercising Repurchase Rights, Etc.

         (a) On or before the fifth (5th) Business Day after the occurrence of a
Repurchase  Event,  the Company shall give to the Holder a Company Notice of the
occurrence of the Repurchase  Event and of the repurchase right set forth herein
arising as a result thereof. Such Company Notice shall set forth:

         (i) the date by which the repurchase right must be exercised, and

         (ii) a description  of the procedure (set forth below) which the Holder
     must follow to exercise the repurchase right.

No failure of the Company to give a Company Notice or defect therein shall limit
the Holder's  right to exercise the  repurchase  right or affect the validity of
the proceedings for the repurchase of this Note or portion hereof.

         (b) To exercise the repurchase  right,  the Holder shall deliver to the
Company on or before the thirtieth  (30th) day after a Company  Notice (or if no
such  Company  Notice has been  given,  within  forty (40) days after the Holder
first learns of the Repurchase Event) (i) a Holder Notice setting forth the name
of the Holder and the principal amount of this Note to be repurchased,  and (ii)
this Note,  duly  endorsed  for  transfer  to the  Company of the portion of the
principal amount of this Note to be repurchased.  A Holder Notice may be revoked
by the  Holder at any time  prior to the time the  Company  pays the  applicable
Repurchase Price to the Holder.

         5.3  Repurchase  Right Upon  Registration  Repurchase  Event.  Upon the
occurrence of a Registration  Repurchase Event, the Holder shall have the right,
at the Holder's  option,  to require the Company to repurchase all of this Note,
or from  time to time any  portion  hereof  (in a  minimum  principal  amount of
$100,000 or integral  multiples  thereof  (or such  lesser  remaining  principal
amount of this Note)),  on the  repurchase  date that is five (5) Business  Days
after the date a Holder  Registration  Repurchase Notice is given by the Holder.
The Holder  shall  exercise  its right to require  repurchase  pursuant  to this
Section 5.3 by giving a Holder Registration Repurchase Notice as follows: (i) if
the Registration  Repurchase Event occurs by reason of the Company's  failure to
timely file the  Registration  Statement with the SEC, within 30 days after such
event or (ii) if the  Registration  Repurchase  Event  occurs  by  reason of the
non-occurrence of the SEC Effective Date within 90 days after the Issuance Date,
at any time prior to the SEC  Effective  Date.  If the Holder shall have given a
Holder Registration Repurchase Notice, the Company shall repurchase this Note or
the portion of this Note as stated in such Holder Registration Repurchase Notice
at a  purchase  price  equal  to the  Registration  Repurchase  Price.  A Holder
Registration Repurchase Notice may be revoked by the Holder at

                                       20

<PAGE>


any  time  prior  to the  time the  Company  pays  the  applicable  Registration
Repurchase Price.

         5.4 Other.

         (a) If the Company  fails to repurchase  on the  applicable  repurchase
date this Note (or  portion  hereof) as to which the  repurchase  right has been
properly  exercised pursuant to this Article V, then the Repurchase Price or the
Registration  Repurchase  Price, as the case may be, for the portion (which,  if
applicable,  may be  all)  of this  Note  which  is  required  to  have  been so
repurchased  shall bear interest to the extent not  prohibited by applicable law
from the applicable repurchase date until paid at the Default Rate.

         (b) If a portion of this Note is to be  repurchased,  upon surrender of
this Note to the  Company in  accordance  with the terms of this  Article V, the
Company shall execute and deliver to the Holder without  service  charge,  a new
Note or Notes,  having the same date hereof and containing  identical  terms and
conditions,  in such denomination or denominations as requested by the Holder in
aggregate  principal  amount equal to, and in exchange  for,  the  unrepurchased
portion of the principal amount of the Note so surrendered.

         (c) The Company  shall notify the Holder of any claim by the Company of
manifest  error in a Holder Notice or a Holder  Registration  Repurchase  Notice
within three  Business Days after the Holder gives such notice and no such claim
of error  shall  limit or  delay  performance  of the  Company's  obligation  to
repurchase such portion of the Note which is not in dispute and (ii) such notice
shall be  deemed  for all  purposes  to be in proper  form  unless  the  Company
notifies  the Holder  within one  Business  Day after such notice has been given
(which notice from the Company shall specify all defects in such notice) and any
Holder  Notice or Holder  Registration  Repurchase  Notice  containing  any such
defect shall  nonetheless be effective on the date given if the Holder  promptly
undertakes in writing to correct all such defects.


                                   ARTICLE VI

                               PAYMENT AT MATURITY

         6.1 Holder  Election.  The Holder shall have the right,  exercisable at
any time  prior to the  Maturity  Date (or such later  date as the  Company  may
permit) by giving a Final Conversion  Election,  to elect that upon the Maturity
Date the  outstanding  amount of this Note  shall be  converted  into  shares of
Common Stock in  accordance  with Section 2.1. The Holder may make such election
by giving  notice  of the Final  Conversion  Election  at any time  prior to the
Maturity  Date.  If the Holder gives a Final  Conversion  Election,  then on the
Maturity Date the  outstanding  amount of this Note shall be converted  into the
number of shares of Common

                                       21

<PAGE>


Stock  determined in accordance with Section 2.1  (determined  without regard to
the  limitation,  if any,  on the Holder  contained  in the second  sentence  of
Section 2.1).  Such  conversion,  however,  shall be subject to the  limitations
contained in Section  2.4.  The Company  shall notify the Holder of any claim by
the Company of manifest error in a Final Conversion Election within one Business
Day after the Holder gives such Final  Conversion  Election and no such claim or
error shall limit or delay performance of the Company's obligation to issue upon
such conversion the number of shares of Common Stock which are not in dispute. A
Final Conversion  Election shall be deemed for all purposes to be in proper form
unless the Company  notifies  the Holder  within one  Business Day after a Final
Conversion  Election has been given (which  notice shall  specify all defects in
the Final Conversion  Election) and any Final Conversion Election containing any
such  defect  shall  nonetheless  be  effective  on the date given if the Holder
promptly undertakes in writing to correct all such defects.

         6.2 Final Maturity Note Issuance.

         (a) If the Holder fails timely to make the Final  Conversion  Election,
then as of the Maturity Date of this Note, the Company shall issue to the Holder
a Final  Maturity Note in the principal  amount herein  provided.  The principal
amount of the Final  Maturity  Note shall be (a) the sum of (1) the  outstanding
principal  amount of this Note, (2) the amount of accrued and unpaid interest on
such principal amount to the Maturity Date and (3) Default Interest,  if any, on
the amount referred to in the immediately  preceding  clause (2) to the Maturity
Date less (b) the sum of (1) the principal amount of this Note, if any, which on
the  Maturity  Date is  inconvertible  pursuant to Section  2.4, (2) accrued and
unpaid  interest on such  principal  amount to the Maturity Date and (3) Default
Interest,  if any, on the amount referred to in the immediately preceding clause
(2) to the Maturity  Date.  Notwithstanding  the issuance of the Final  Maturity
Note,  the Company  shall  remain  liable for payment of all unpaid  amounts due
under  this Note which are not  included  in the  principal  amount of the Final
Maturity Note,  including,  without  limitation,  the  Redemption  Price and the
Repurchase  Price.  If the Holder  shall have failed to give a Final  Conversion
Election  prior to the  Maturity  Date,  then  prior to  issuance  of the  Final
Maturity  Note,  the  Company  shall  have the right  within  15 days  after the
Maturity  Date to  contact  the  Holder  and for a period of 15 days  after such
notice to seek a Final Conversion Election from the Holder;  provided,  however,
that if the Holder  fails to give a Final  Conversion  Election  within  such 15
days, the Company shall  immediately  issue the Final Maturity Note, which shall
be dated the Maturity Date.

         (b) The Holder of this Note by its acceptance hereof,  acknowledges and
agrees  that  the  Final  Maturity  Note  shall  bear a  restrictive  legend  in
substantially  the following form (and a stop-transfer  order to such effect may
be placed against transfer of the Final Maturity Note):

                                       22

<PAGE>


This Final  Maturity Note has not been  registered  under the  Securities Act of
1933, as amended or any state securities laws. This Final Maturity Note has been
acquired for investment only and may not be sold, transferred or assigned in the
absence of such registration or an opinion of counsel reasonably satisfactory in
form, scope and substance to the Company that such registration is not required.

         This Final Maturity Note may not be  transferred  except as provided in
Section 3.7 of the Final Maturity Note.


                                   ARTICLE VII

                                   DEFINITIONS

         7.1 Certain Defined Terms.

         (a) All the  agreements or  instruments  herein defined shall mean such
agreements or instruments as the same may from time to time be  supplemented  or
amended or the terms thereof waived or modified to the extent  permitted by, and
in accordance with, the terms thereof and of this Note.

         (b) The  following  terms  shall  have  the  following  meanings  (such
meanings to be equally  applicable  to both the singular and plural forms of the
terms defined):

         "Acceleration  Percentage" means with respect to the date of payment in
full of the  amount  due in  respect  of this Note as set forth in clause (X) of
Article IV, the applicable percentage set forth below determined with respect to
such date as follows:

     Date                                                             Percentage
     ----                                                             ----------

     Issuance Date to and including the 120th day thereafter            115.0%
     
     121st through 270th day after the Issuance Date                    117.5%

     On and after the 271st day after the Issuance Date                 122.5%

         "Affiliate"  means,  with respect to any Person,  any other Person that
directly,  or  indirectly  through  one or  more  intermediaries,  controls,  is
controlled by or under common control with the subject  Person.  For purposes of
the term  "Affiliate",  the term "control"  (including the terms  "controlling",
"controlled by" and "under common control with") means

                                       23

<PAGE>


the  possession,  direct  or  indirect,  of the  power to direct or to cause the
direction  of the  management  and  policies  of a Person,  whether  through the
ownership of securities, by contract or otherwise.

         "Aggregated  Person"  means any person  whose  beneficial  ownership of
shares  of  Common  Stock  would  be  aggregated  with the  Holder's  beneficial
ownership of shares of Common  Stock for  purposes of Section  13(d) of the 1934
Act and Regulation 13D-G thereunder.

         "AMEX" means the American Stock Exchange, Inc.

         "Applicable Rate" means five percent (5%) per annum.

         "Business Combination  Redemption  Percentage" means for any redemption
of this Note in accordance  with Section  2.3(c) the  applicable  percentage set
forth below:

     Redemption Date                                                  Percentage
     ---------------                                                  ----------

     Issuance Date through 180th day thereafter the Issuance Date       125.0%

     On and after the 181st day after the Issuance Date                 130.0%

         "Business  Day" shall mean any day other than a  Saturday,  Sunday or a
day on which commercial banks in The City of New York are authorized or required
by law or executive order to remain closed.

         "Cash,  Cash  Equivalent  and  Short-Term  Investment  Balances" of the
Company at any date shall be determined from the Company's  books  maintained in
accordance  with  Generally  Accepted  Accounting  Principles,  and shall  mean,
without duplication,  the sum of (1) the cash owned by the Company on such date,
(2) all assets which would on a balance sheet of the Company prepared as of such
date in accordance with Generally Accepted  Accounting  Principles be classified
as cash or cash equivalents and (3) all assets which would on a balance sheet of
the  Company  prepared as of such date in  accordance  with  Generally  Accepted
Accounting Principles be classified as short-term investments.

         "Common  Stock" shall mean the Common Stock,  $.01 par value,  together
with the related  Preferred  Share  Purchase  Rights or similar  rights,  of the
Company or any shares of capital  stock and related  rights of the Company  into
which such stock shall be changed or reclassified after the Issuance Date.

         "Company"  shall have the meaning  provided in the first  paragraph  of
this Note.

                                       24

<PAGE>


         "Company  Certificate"  means a certificate of the Company signed by an
Officer.

         "Company  Notice" means a Company Notice in the form attached hereto as
Exhibit F.

         "Computed  Price"  for any date  means the  arithmetic  average  of the
lowest per share  Trading  Price on the two Trading  Days during the  applicable
Measurement  Period  for such date on which  the two  lowest  per share  Trading
Prices occur.

         "Conversion  Notice"  means a Notice of  Conversion of 5% Senior Custom
Convertible  Note due 2000  substantially in the form attached hereto as Exhibit
A,  properly  completed  and  duly  executed  by  the  Holder  or  the  Holder's
attorney-in-fact.

         "Conversion  Price"  for any date means the  arithmetic  average of the
lowest per share  Trading  Price on the two Trading  Days during the  applicable
Measurement  Period  for such date on which  the two  lowest  per share  Trading
Prices occur; provided,  however, that on any date on or after January 19, 1998,
the Conversion Price shall not be greater than 115% of the arithmetic average of
the Market Price of the Common  Stock for the period of twenty (20)  consecutive
Trading Days ending one Trading Day prior to January 19, 1998.

         "Default  Interest"  shall  have  the  meaning  provided  in the  first
paragraph of this Note.

         "Default Rate" means 10 percent per annum (or such lesser rate equal to
the highest rate permitted by applicable law).

         "Event of Default" shall have the meaning provided in Article IV.

         "Final  Conversion  Election" means a Holder Notice of Final Conversion
of 5% Senior Custom Convertible Note in the form attached hereto as Exhibit I.

         "Final  Maturity  Note"  shall mean a note issued by the Company in the
form attached hereto as Exhibit J.

         "Generally  Accepted  Accounting  Principles"  for any Person means the
generally  accepted  accounting  principles and practices applied by such Person
from time to time in the preparation of its audited financial statements.

         "Holder" shall have the meaning provided in the first paragraph of this
Note.

                                       25

<PAGE>


         "Holder  Notice" means a Holder  Notice in the form attached  hereto as
Exhibit G.

         "Holder  Registration  Repurchase  Notice" means a Holder  Registration
Repurchase Notice in the form attached hereto as Exhibit H.

         "Inconvertibility  Day" means any  Trading Day on which (x) the Company
would not have been  required  to convert in  accordance  with  Section  2.1 any
portion of this Note as a consequence  of the  limitations  set forth in Section
2.4(a)  had the  Holder  converted  this  Note in  full  on  such  Trading  Day,
determined at the  Conversion  Price  applicable on such Trading Day and without
regard to the limitation,  if any on the Holder contained in the second sentence
of  Section  2.1 or (y) on which the  Company  does not have  reserved  from its
authorized  and unissued  shares of Common Stock for purposes of  conversion  of
this Note and the Other  Notes the number of shares of Common  Stock so required
to be reserved pursuant to Section 2.2.

         "Inconvertibility Notice" means a notice from the Company to the Holder
in the form set forth in Exhibit B or a notice from the Holder to the Company in
the form set forth in Exhibit C.

         "Inconvertible Portion" means (1) in the case of a Maximum Share Amount
Inconvertibility,  the portion of this Note (which, if applicable,  shall be all
of this  Note) as shall not,  on the  Business  Day  immediately  preceding  the
applicable Redemption Date, be convertible into shares of Common Stock by reason
of the limitations set forth in Section 2.4(a) (determined without regard to the
limitation,  if any, on the Holder  contained in the second  sentence of Section
2.1), or (2) in the case of a  Registration  Restriction  Inconvertibility,  the
portion of this Note (which, if applicable,  shall be all of this Note) as shall
not, on the Business Day immediately  preceding the applicable  Redemption Date,
be convertible into shares of Common Stock which are covered by the Registration
Statement and available  for resale by the Holder  pursuant to the  Registration
Statement.

         "Indebtedness"   as  used  in   reference   to  any  Person  means  all
indebtedness of such person for borrowed money,  the deferred  purchase price of
property,  goods and services and obligations under leases which are required to
be capitalized in accordance with Generally Accepted  Accounting  Principles and
shall include all such  indebtedness  guaranteed in any manner by such person or
in effect  guaranteed by such person through a contingent  agreement to purchase
and all  indebtedness  for the  payment or  purchase  of which  such  person has
contingently  agreed to advance or supply funds and all indebtedness  secured by
mortgage or other lien upon property owned by such person,  although such person
has not assumed or become liable for the payment of such indebtedness,  and, for
all purposes hereof,  such  indebtedness  shall be treated as though it has been
assumed by such person.

                                       26

<PAGE>


         "Interest Payment Dates" shall mean each February 15, May 15, August 15
and November 15 and the Maturity Date.

         "Issuance  Date"  means the date this Note was  issued to the  original
Holder of this Note.

         "Issuing  Agent" means  BankBoston,  N.A.,  its successor or such other
person who shall be serving as transfer agent and registrar for the Common Stock
and who shall have been authorized by the Company to act as conversion agent for
the Note in accordance with the Transfer Agent  Agreement and the name,  address
and telephone  number of whom shall have been given to the Holder by notice from
the Company.

         "Majority  Holders"  means at any time the holders of this Note and the
Other  Notes  which  hold Notes and Other  Notes  which,  based on the  original
principal  amount  thereof,  represent  a  majority  of the  original  aggregate
principal amount of this Note and the Other Notes, whether or not outstanding at
such time.

         "Mandatory  Redemption  Waiver" means a Mandatory  Redemption Waiver in
the form attached hereto as Exhibit E.

         "Market  Price" of any  security on any date shall mean the closing bid
price of such security on such date on Nasdaq or such other securities  exchange
or other market on which such security is listed for trading  which  constitutes
the principal securities market for such security, as reported by Nasdaq or such
exchange or other market.

         "Maturity  Date" means  September  [BEFORE  SIGNING  NOTE INSERT DAY OF
CLOSING DATE], 2000.

         "Maximum  Share  Amount"  means  [INSERT PRO RATA PORTION OF 20% OF THE
NUMBER OF SHARES  OUTSTANDING  IMMEDIATELY PRIOR TO THE TIME THE NOTE IS ISSUED]
shares (such amount to be subject to equitable  adjustment  from time to time on
terms  reasonably  acceptable to the Holder for stock splits,  stock  dividends,
combinations,  capital reorganizations and similar events relating to the Common
Stock occurring after the Issuance Date) of Common Stock.

         "Maximum Share Amount Inconvertibility" means the occurrence of five or
more  Inconvertibility  Days ending on or after the 90th day after the  Issuance
Date within any period of ten consecutive Trading Days.

         "Measurement Period" means with respect to any date the period of 20

                                       27

<PAGE>


consecutive Trading Days ending one Trading Day prior to such date.

         "Nasdaq" means the Nasdaq National Market.

         "1933 Act" means the Securities Act of 1933, as amended.

         "1934 Act" means the Securities Exchange Act of 1934, as amended.

         "Net Cash, Cash Equivalent and Short-Term Investment Balances" means at
any time the Company's Cash and Cash Equivalent Balances less the sum of (1) the
amount of any  outstanding  Indebtedness of any Person which is secured in whole
or in part by Cash and Cash  Equivalent  Balances  plus (2) the  maximum  amount
which is not  outstanding  and which may be borrowed  pursuant to any  revolving
credit  facility or any commitment to lend of or to any Person which at the time
it  becomes  outstanding  will be  secured  in whole or in part by Cash and Cash
Equivalent Balances.

         "Note"  means  this  instrument  as  originally  executed,  or if later
amended or supplemented, then as so amended or supplemented.

         "Note Purchase Agreement" shall mean the Note Purchase Agreement, dated
as of September 8, 1997,  by and between the Company and the original  Holder of
this Note.

         "NYSE" shall mean the New York Stock Exchange, Inc.

         "Officer" means the Chairman of the Board, the Chief Executive Officer,
the President or the Chief Financial Officer of the Company.

         "Other Notes" means the several 5% Senior Custom  Convertible Notes due
2000 issued by the Company pursuant to the Other Note Purchase Agreements.

         "Other  Note  Purchase  Agreements"  means the  several  Note  Purchase
Agreements,  dated as of the date of the Note  Purchase  Agreement,  between the
Company and the several buyers named therein.

         "Payment  Shares"  means the  shares of  Common  Stock and the  related
Preferred  Share Purchase Rights issuable in payment of interest on this Note in
accordance with Section 1.1.

         "Permitted Indebtedness" means

                                       28

<PAGE>


         (1)  Indebtedness  not in excess of $8.0  million  aggregate  principal
     amount which is either (x) outstanding on the Issuance Date and which would
     be  reflected  on a balance  sheet of the Company as of the  Issuance  Date
     prepared in accordance with Generally Accepted Accounting Principles or (y)
     Indebtedness  incurred  after the  Issuance  Date  pursuant to  commitments
     available  to the  Company  under its  lease  line in effect on the date of
     execution and delivery of this Agreement;

         (2)  Indebtedness  incurred  after the Issuance Date  consisting of (A)
     equipment  lease  obligations  or  other  equipment  financings  which  are
     required to be capitalized in accordance with Generally Accepted Accounting
     Principles; (B) Indebtedness incurred in connection with the acquisition of
     furnitures, fixtures and equipment; and (C) Indebtedness incurred after the
     Issuance  Date that is secured  solely by the  Company's  interest  in real
     estate, improvements to real estate and office and laboratory facilities;

         (3)  Indebtedness  incurred in  connection  with a strategic  alliance,
     collaboration,  joint venture,  partnership or other similar arrangement of
     the Company with another  Person which is engaged in a business  similar to
     or related to the business of the Company; and

         (4) Indebtedness  (other than as permitted by the preceding clauses (1)
     through (4)) in a principal amount not in excess of $3 million  outstanding
     at any one time;

so long as (x) in the case of  Indebtedness  permitted by the preceding  clauses
(2) through  (4), on the date of  incurrence  of such  Indebtedness  no Event of
Default has  occurred  and is  continuing,  and (y) in the case of  Indebtedness
permitted by the preceding  clause (2), the aggregate amount thereof (other than
any amount thereof permitted by clause (1)(y) of this definition) outstanding at
any one time does not exceed $12 million.

         "Permitted  Transferee"  means  any  person  who is (1) an  "accredited
investor"  as defined in  Regulation D under the 1933 Act and (2) a Person which
(A) has the same  investment  adviser  as the Holder or the holder of any of the
Other Notes,  (B) has an investment  adviser which is under common  control with
the investment  adviser to the Holder or the holder of any of the Other Notes or
(C) is an Affiliate of the Holder or the holder of any Other Note.

         "Person"  means  an  individual,   partnership,   corporation,  limited
liability  company,  trust or incorporated  organization,  and a government or a
governmental agency or political subdivision.

         "Pooling  Standards" means Opinion No. 16 of the Accounting  Principles
Board

                                       29

<PAGE>


(or any  successor  accounting  standard of the Financial  Accounting  Standards
Board  (or  any  successor  or  replacement   Person  or  board  the  accounting
pronoucements  of which are  applicable to issuers  having a class of securities
registered  pursuant  to  Section  12(b)  or 12(g)  of the  1934  Act))  and any
applicable  requirements of the SEC relating to pooling of interests  accounting
for business  combination  transactions,  in each case as in effect from time to
time.

         "Preferred  Share Purchase  Rights" means the Preferred  Share Purchase
Rights issued or issuable pursuant to the Rights Agreement (or any similar right
hereafter issued by the Company with respect to the Common Stock).

         "Redemption  Date" means the date which is five Business Days after the
date the Holder gives a Redemption Election to the Company.

         "Redemption  Election"  means (1) a notice by the Holder to the Company
substantially  in the form set forth in  Exhibit D or (2) a notice by the Holder
to the  Company  included  in the form of  Inconvertibility  Notice set forth in
Exhibit C.

         "Redemption  Election  Period"  means,  with  respect  to a  particular
Maximum   Share   Amount    Inconvertibility    or   Registration    Restriction
Inconvertibility,  the  period of ten  Business  Days after the later of (x) the
date an  Inconvertibility  Notice  with  respect to such  Maximum  Share  Amount
Inconvertibility  or Registration  Restriction  Inconvertibility is given or (y)
the date such  Inconvertibility  Notice was  required  to have been given by the
Company.

         "Redemption Percentage" means with respect to each Redemption Date, the
applicable  percentage set forth below  determined  with respect to such date as
follows:

     Redemption Date                                                  Percentage
     ---------------                                                  ----------

     Issuance Date through and including the 120th day thereafter       112.5%

     121st through 270th day after the Issuance Date                    115.0%

     On and after the 271st day after the Issuance Date                 120.0%

         "Redemption  Price" means an amount in cash equal to the sum of (1) the
product  obtained by multiplying (A) the sum of (i) the principal amount of this
Note to be redeemed on a particular Redemption Date plus (ii) accrued and unpaid
interest  on  such  principal  amount  to such  Redemption  Date  times  (B) the
applicable  Redemption  Percentage plus (2) accrued and unpaid Default Interest,
if any, on the amount referred to in the immediately preceding clause (1)(A)(ii)
at the rate provided in this Note to such Redemption Date.

                                       30

<PAGE>


         "Registration  Repurchase  Event" means the occurrence of either of the
following events:

         (a) the Company  fails to file the  Registration  Statement  within the
     30-day period provided in Section  8(a)(1) of the Note Purchase  Agreement;
     or

         (b) the SEC  Effective  Date shall not have  occurred  on or before the
     date which is 90 days after the Issuance Date.

         "Registration  Repurchase  Price"  means an amount in cash equal to the
sum of (1) the product  obtained by multiplying (A) the sum of (i) the principal
amount of this Note to be repurchased  plus (ii) accrued and unpaid  interest on
such principal  amount to the date of such  repurchase  times (B) 115%, plus (2)
accrued and unpaid Default  Interest,  if any, on the amount  referred to in the
immediately preceding clause (1)(A)(ii) at the rate provided in this Note to the
date of repurchase in accordance with Article V.

         "Registration Restriction Inconvertibility" means that, notwithstanding
Rule 416  under  the  1933 Act or the  provisions  of  Section  8(b) of the Note
Purchase  Agreement,  the  Registration  Statement  is not  deemed to cover such
indeterminate  number of additional  shares of Common Stock as shall be issuable
upon  conversion  of  this  Note  based  on  changes  from  time  to time in the
Conversion  Price,  and on any five  Trading  Days  ending  on or after  the SEC
Effective Date within any period of ten  consecutive  Trading Days the number of
shares of Common Stock  issuable  upon  conversion of this Note in full had this
Note  been  converted  in full  into  Common  Stock on each  such  Trading  Day,
determined  at the  Conversion  Price  applicable  on each such  Trading Day and
without regard to the limitation,  if any, on the Holder contained in the second
sentence  of Section  2.1,  would  exceed  the number of shares of Common  Stock
covered  by the  Registration  Statement  and  available  for sale by the Holder
pursuant to the Registration Statement.

         "Registration  Statement" means the Registration  Statement required to
be filed  by the  Company  with the SEC  pursuant  to  Section  8(a) of the Note
Purchase Agreement.

         "Repurchase  Event"  means  the  occurrence  of any  one or more of the
following events:

         (a) For any period of five consecutive  Trading Days following the date
     hereof there shall be no reported  sale price of the Common Stock on any of
     Nasdaq, the NYSE or the AMEX;

         (b) The Common  Stock  ceases to be listed for  trading on Nasdaq,  the
     NYSE

                                       31

<PAGE>


or the AMEX;

         (c) Any  consolidation  or merger of the Company or any Subsidiary with
     or  into  another  entity  (other  than  a  merger  or  consolidation  of a
     Subsidiary  into  the  Company  or a  wholly-owned  Subsidiary)  where  the
     stockholders of the Company  immediately  prior to such  transaction do not
     collectively own at least 51% of the outstanding  voting  securities of the
     surviving corporation of such consolidation or merger immediately following
     such transaction;  or the sale of all or substantially all of the assets of
     the Company and its Subsidiaries;

         (d) The  adoption of any  amendment  to the  Company's  Certificate  of
     Incorporation (other than any certificate designating a series of preferred
     stock of the Company) which materially and adversely  affects the rights of
     the Holder or the taking of any other action which materially and adversely
     affects the rights of the Holder;

         (e) The inability of the Holder for (x) 20 Trading Days (whether or not
     consecutive)  during the period  commencing on the SEC  Effective  Date and
     ending on the first anniversary of the Issuance Date or (y) 60 Trading Days
     (whether or not consecutive)  during the period from the SEC Effective Date
     to the Maturity Date, to sell shares of Common Stock issued upon conversion
     of this Note pursuant to the Registration Statement required to be filed by
     the Company  pursuant to the Note  Purchase  Agreement (1) by reason of the
     requirements  of the  1933  Act,  the  1934  Act or  any  of the  rules  or
     regulations  under either thereof or (2) due to the Registration  Statement
     containing  any untrue  statement  of material  fact or omitting to state a
     material  fact  required  to be stated  therein  or  necessary  to make the
     statements  therein not  misleading  or other  failure of the  Registration
     Statement to comply with the rules and regulations of the SEC; or

         (f) The  occurrence of any Event of Default  specified in Article IV of
     this Note.

         "Repurchase  Price"  means with respect to any  repurchase  pursuant to
Sections  5.1 and 5.2 an  amount  in cash  equal  to the sum of (1) the  product
obtained by multiplying the sum of (A) the outstanding  principal amount of this
Note plus (B) accrued and unpaid  interest on such principal  amount to the date
of such  repurchase  times (x) 112.5%,  if the date of such  repurchase is on or
before the 120th day after the Issuance  Date,  (y) 115.0%,  if the date of such
repurchase is on or after the 121st day after the Issuance Date and on or before
the 270th  day  after the  Issuance  Date,  or (z)  120.0%,  if the date of such
repurchase is on or after the 271st day after the Issuance Date plus (2) accrued
and  unpaid  Default  Interest,  if  any,  on  the  amount  referred  to in  the
immediately  preceding  clause  (1)(B) at the rate  provided in this Note to the
date of such repurchase.

                                       32

<PAGE>


         "Rights  Agreement" means the Rights  Agreement,  dated as of August 1,
1995, by and between the Company and Boston EquiServe, as Rights Agent.

         "SEC" means the Securities and Exchange Commission.

         "SEC Effective Date" means the date on which the Registration Statement
is first declared effective by the SEC.

         "Significant  Subsidiary"  means a Subsidiary  which is a  "significant
subsidiary,"  as that term is defined in Rule 1-02(w) of  Regulation  S-X of the
SEC as in effect on the date of this Agreement.

         "Stock  Payment  Option"  shall have the  meaning  provided  in Section
1.1(a).

         "Stockholder  Approval"  means the  approval by a majority of the votes
cast by the  holders  of  shares of  Common  Stock (in  person or by proxy) at a
meeting of the  stockholders of the Company (duly convened at which a quorum was
present),  or a written consent of holders of shares of Common Stock entitled to
such number of votes given without a meeting,  of the issuance by the Company of
20% or more of the  outstanding  Common  Stock of the  Company for less than the
greater of the book or market  value of such Common Stock on  conversion  of the
Note and the Other Notes,  as and to the extent  required  under Rule 4460(i) of
Nasdaq (or any successor or replacement provision thereof).

         "Subsidiary"  means any corporation or other entity of which a majority
of the capital stock or other ownership  interests  having ordinary voting power
to elect a  majority  of the  board of  directors  or other  persons  performing
similar functions are at the time directly or indirectly owned by the Company.

         "Tender Offer" means a tender offer or exchange offer.

         "Trading  Day"  means a day on which  either  the  national  securities
exchange or Nasdaq which then  constitutes the principal  securities  market for
the Common Stock is open for general trading.

         "Trading  Price" on any date means the lowest sale price  (regular way)
for one share of the Common Stock on such date,  on the first  applicable  among
the  following:  (a) the  national  securities  exchange  on which the shares of
Common Stock are listed which  constitutes the principal  securities  market for
the Common Stock,  (b) Nasdaq,  (c) the Nasdaq SmallCap Market or (d) such other
market as at the time  constitutes  the principal  trading market for the Common
Stock, in any such case as reported by Bloomberg, L.P. (subject to equitable

                                       33

<PAGE>


adjustment  from time to time on terms  reasonably  acceptable  to the  Majority
Holders for (i) stock splits,  (ii) stock dividends,  (iii)  combinations,  (iv)
capital  reorganizations,  (v) issuance to all holders of Common Stock of rights
or warrants to  purchase  shares of Common  Stock at a price per share less than
the Trading Price which would otherwise be applicable,  (vi) the distribution by
the Company to all holders of Common Stock of evidences of  indebtedness  of the
Company or cash (other than  regular  quarterly  cash  dividends),  (vii) tender
offers by the Company or any  subsidiary of the Company or other  repurchases of
shares of Common Stock in one or more transactions which, individually or in the
aggregate,  result  in the  purchase  of  more  than  10% of  the  Common  Stock
outstanding and (viii) similar events relating to the Common Stock, in each such
case which occur on or after the Execution Date); provided,  however, that if on
any  Trading  Day there shall be no  reported  sale price  (regular  way) of the
Common Stock,  the "Trading  Price" on such Trading Day shall be the lowest sale
price  (regular way) of the Common Stock on the Trading Day next  preceding such
Trading Day on which a sale price (regular way) for the Common Stock has been so
reported.

         "Transaction  Documents" means this Note, the Note Purchase  Agreement,
the Final  Maturity Note,  the Transfer  Agent  Agreement,  the Warrants and the
other agreements, instruments and documents contemplated hereby and thereby.

         "Transfer Agent Agreement" means the Transfer Agent Agreement, dated as
of September 8, 1997, by and among the Company,  the Issuing Agent, the original
Holder of this Note and the Original Holders of the Other Notes.

         "Warrants"  means Common Stock Purchase  Warrants of the Company issued
to the original holder of this Note pursuant to the Note Purchase Agreement.


                                  ARTICLE VIII

                                  MISCELLANEOUS

         8.1 Failure or Indulgency  Not Waiver.  No failure or delay on the part
of the Holder in the exercise of any power,  right or privilege  hereunder shall
operate as a waiver  thereof,  nor shall any single or partial  exercise  of any
such power,  right or privilege preclude other or further exercise thereof or of
any other right, power or privileges. All rights and remedies existing hereunder
are  cumulative  to, and not  exclusive  of, any  rights or  remedies  otherwise
available.

         8.2 Notices.  Except as otherwise  specifically  provided  herein,  any
notice  herein  required or permitted to be given shall be in writing and may be
personally served, sent

                                       34

<PAGE>


by  telephone  line  facsimile  transmission  or delivered by courier or sent by
United  States  mail and  shall be deemed to have been  given  upon  receipt  if
personally  served,  sent by telephone  line facsimile  transmission  or sent by
courier or three (3) days after  being  deposited  in the  United  States  mail,
certified,  with postage pre-paid and properly  addressed,  if sent by mail. For
the purposes hereof,  the address of the Holder shall be as shown on the records
of the Company (telephone line facsimile transmission number ____________);  and
the  address  of  the  Company  shall  be 351  Galveston  Drive,  Redwood  City,
California  94063-4720,  Attention:  Vice  President,  Finance  (telephone  line
facsimile  transmission  number  (650)  306-4016).  A copy of any  notice to the
Company pursuant to this Note shall also be provided to Cooley Godward LLP, 3000
El Camino Real,  Palo Alto,  California  94306,  Attention:  Brian Cunnigham and
Suzanne  Sawochka  Hooper  (telephone line facsimile  transmission  number (650)
857-0663).  The Holder or the  Company  may change its  address  for  service by
service of written notice to the other as herein provided.

         8.3  Amendment  Provision.  Neither this Note or any Other Note nor any
terms hereof or thereof may be changed, waived,  discharged or terminated unless
such  change,  waiver,  discharge  or  termination  is in writing  signed by the
Majority Holders, provided that no such change, waiver, discharge or termination
shall,  without  the  consent of the Holder and the  holders of the Other  Notes
affected  thereby,  (i) extend the scheduled  final maturity of this Note or any
Other Note, or reduce the rate or extend the time of payment of interest  (other
than as a result of waiving the  applicability of any  post-default  increase in
interest  rates)  hereon or  thereon or reduce the  principal  amount  hereof or
thereof or the Redemption  Price,  Repurchase  Price or Registration  Repurchase
Price,  (ii) amend,  modify or waive any  provision of this  Section 8.3,  (iii)
reduce any  percentage  specified  in, or otherwise  modify,  the  definition of
Majority  Holders or (iv) except as provided in this Note,  change the method of
calculating the Conversion Price in a manner adverse to the Holder.

         8.4 Assignability.  This Note shall be binding upon the Company and its
successors, and shall inure to the benefit of and be binding upon the Holder and
its successors and permitted  assigns.  The Company may not assign its rights or
obligations under this Note.

         8.5  Certain  Expenses.  The Company  shall pay on demand all  expenses
incurred by the Holder,  including reasonable attorneys' fees and expenses, as a
consequence  of, or in connection  with, (x) any default or breach of any of the
Company's  obligations  set  forth  in the  Transaction  Documents  and  (y) the
enforcement or  restructuring  of any right of,  including the collection of any
payments due, the Holder under the Transaction  Documents,  including any action
or proceeding  relating to such  enforcement  or any order,  injunction or other
process seeking to restrain the Company from paying any amount due the Holder.

         8.6 Governing  Law. This Note shall be governed by the internal laws of
the

                                       35

<PAGE>


State of California, without regard to the principles of conflict of laws.

         8.7  Transfer  of  Note.  This  Note  has  not  been  and is not  being
registered under the provisions of the 1933 Act or any state securities laws and
this  Note may not be  transferred  unless  (1) the  transferee  is a  Permitted
Transferee  and (2) the Holder shall have delivered to the Company an opinion of
counsel, reasonably satisfactory in form, scope and substance to the Company, to
the effect that this Note may be sold or transferred without  registration under
the 1933 Act. Prior to any such transfer, such transferee shall have represented
in writing to the Company that such  transferee  has requested and received from
the Company all information  relating to the business,  properties,  operations,
condition  (financial  or other),  results of  operations  or  prospects  of the
Company  deemed  relevant  by such  transferee;  that such  transferee  has been
afforded  the  opportunity  to ask  questions  of  the  Company  concerning  the
foregoing  and has had the  opportunity  to obtain and  review the  Registration
Statement and the prospectus  included therein,  each as amended or supplemented
to the  date  of  transfer  to  such  transferee,  and  the  reports  and  other
information  concerning the Company which at the time of such transfer have been
filed by the  Company  with the SEC  pursuant  to the  1934  Act and  which  are
incorporated by reference in such prospectus as of the date of such transfer. If
such transfer is intended to assign the rights and  obligations  under  Sections
5(a), 5(b) and 8 of the Note Purchase  Agreement,  such transfer shall otherwise
be made in compliance with Section 10.7 of the Note Purchase Agreement.

         8.8 Enforceable Obligation. The Company represents and warrants that at
the time of the  original  issuance of this Note it received  the full  purchase
price  payable  pursuant to the Note  Purchase  Agreement  in an amount at least
equal to the original  principal  amount of this Note,  and that this Note is an
enforceable  obligation  of the  Company  which is not  subject  to any  offset,
reduction, counterclaim or disallowance of any sort.

         8.9  Certain  Amounts.  Whenever  pursuant  to this Note the Company is
required to pay an amount in excess of the outstanding  principal amount (or the
portion  thereof  required  to be paid at that  time)  plus  accrued  and unpaid
interest  plus  Default  Interest on such  interest,  the Company and the Holder
agree that the actual  damages to the Holder from the receipt of cash payment on
this Note may be  difficult  to  determine  and the  amount to be so paid by the
Company  represents  stipulated  damages  and not a penalty  and is  intended to
compensate  the Holder in part for loss of the  opportunity to convert this Note
and to earn a return  from the sale of  shares  of Common  Stock  acquired  upon
conversion  of this Note at a price in excess of the price paid for such  shares
pursuant to this Note.  The Company and the Holder hereby agree that such amount
of stipulated  damages is not plainly  disproportionate  to the possible loss to
the Holder from the receipt of a cash payment without the opportunity to convert
this Note into shares of Common Stock.

                                       36

<PAGE>


         8.10  Replacement  of Notes.  Upon  receipt by the  Company of evidence
reasonably  satisfactory  to it  of  the  ownership  of  and  the  loss,  theft,
destruction  or  mutilation  of this Note and (a) in the case of loss,  theft or
destruction, of indemnity from the Holder reasonably satisfactory in form to the
Company (and without the  requirement to post any bond or other security) or (b)
in the case of  mutilation,  upon surrender and  cancellation  of this Note, the
Company  will  execute and  deliver to the Holder a new Note of like  tenor.  In
connection  with the  issuance  of any such new Note,  the  Holder  shall pay or
reimburse the Company for the  reasonable  and  documented  attorneys'  fees and
expenses  incurred by the Company in connection  therewith (but not in excess of
$500.00 for each such issuance).

                                       37

<PAGE>


         IN WITNESS  WHEREOF,  the  Company has caused this Note to be signed in
its name by its duly  authorized  officer on the day and in the year first above
written.

                                                       SUGEN, INC.



                                                       By:______________________
                                                           Name:
                                                           Title:

                                       38

<PAGE>


                                                                       Exhibit A

                              NOTICE OF CONVERSION
                  OF 5% SENIOR CUSTOM CONVERTIBLE NOTE DUE 2000
                                 OF SUGEN, INC.

To: SUGEN, Inc.                                  with a copy to:
    351 Galveston Drive
    Redwood City, California  94063-4720         Cooley Godward LLP
                                                 5 Palo Alto Square
    Attention:  Vice President, Finance          3000 El Camino Real
                                                 Palo Alto, California  94306
    Primary Facsimile No.:  (650) 306-4016
    Alternative Facsimile No. (if primary not    Attention:   Brian C. 
       functioning):  (650) 369-0741                            Cunningham, Esq.
                                                              Suzanne Sawochka 
                                                                Hooper, Esq.

                                                 Facsimile No.:  (650) 857-0663
    BankBoston N.A.,
       as Issuing Agent
    150 Royall Street
    Canton, Massachusetts 02021

    Attention:   Ms. Debra Spearin,
                 Special Issuances

    Facsimile No.:  (617) 575-2804


         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"),  the undersigned hereby elects to convert $___________ of the
Note,  equal  to  the  sum  of  $___________   principal  amount  of  the  Note,
$___________  of  accrued  and  unpaid  interest  on such  principal  amount and
$___________ of Default Interest on such interest into shares of Common Stock of
SUGEN, INC., a Delaware  corporation (the "Company"),  at a Conversion Price per
share equal to  $___________.  Capitalized  terms used herein and not  otherwise
defined herein have the respective meanings provided in the Note.

         (2) The number of shares of Common Stock  issuable upon the  conversion
of the Note to which this Notice relates is ___________.

         (3) If the  conversion  of the  Note by this  Notice  is  based  on the
Trading Prices

                                       A-1

<PAGE>


during a Measurement  Period, set forth below or on a schedule which accompanies
this Notice are the Trading Prices during the Measurement  Period  applicable to
this Notice and an  indication  of the two Trading  Prices used to determine the
Conversion Price set forth above.

                       Date                                 Trading Price
                       ----                                 -------------

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                                       A-2

<PAGE>

                ___________, ______                     $____________________

                ___________, ______                     $____________________

                ___________, ______                     $____________________

         (4) Please issue a certificate or certificates for __________ shares of
Common Stock in the name(s) specified  immediately below or, if additional space
is necessary, on an attachment hereto:


                  _____________________                 _____________________
                  Name                                  Name


                  _____________________                 _____________________
                  Address                               Address


                  _____________________                 _____________________
                  SS or Tax ID Number                   SS or Tax ID Number

                  Delivery Instructions
                  for Common Stock:



         (5) The Holder  hereby  represents  to the Company that the exercise of
conversion  rights  contained  herein does not violate the provisions of Section
2.1 of the Note relating to beneficial ownership in excess of 4.9% of the Common
Stock.

         (6) The Holder hereby  represents and warrants that it has complied and
will comply with the applicable  requirements of Sections 8(c)(3) and 8(c)(5) of
the Note Purchase  Agreement with respect to the shares of Common Stock issuable
upon the conversion of the Note

                                       A-3

<PAGE>


to which this Notice relates.

         (7) If the shares of Common Stock issuable upon  conversion of the Note
have not been  registered  under the  Securities  Act of 1933,  as amended  (the
"Act"),  the  undersigned  represents and warrants that (i) the shares of Common
Stock  issuable upon the conversion of the Note to which this Notice relates are
being acquired for the account of the undersigned for investment, and not with a
view to, or for resale in connection  with, the distribution  thereof,  and that
the  undersigned  has no present  intention of  distributing  or reselling  such
shares  and (ii) the  undersigned  is an  "accredited  investor"  as  defined in
Regulation D under the 1933 Act. The  undersigned  further  agrees that (A) such
shares shall not be sold or transferred  unless either (i) they first shall have
been registered  under the 1933 Act and applicable state securities laws or (ii)
the  Company  shall  have  been  furnished  with an  opinion  of  legal  counsel
reasonably  satisfactory to the Company to the effect that such sale or transfer
is exempt from the registration  requirements of the 1933 Act and (B) until such
shares are registered  under the 1933 Act, the Company may place a legend on the
certificate(s)  for  the  shares  to  that  effect  and  place  a  stop-transfer
restriction in its records relating to the shares.



                                             NAME:



Date _________________________               ___________________________________
                                                  Signature of Registered Holder
                                                  (Must  be  signed  exactly  as
                                                  name appears in the Note.)

                                       A-4

<PAGE>


                                                                       Exhibit B

                         COMPANY INCONVERTIBILITY NOTICE
         (Section 2.4(b) of 5% Senior Custom Convertible Note due 2000)

TO:_______________________
     (Name of Holder)

         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"),  SUGEN, Inc., a Delaware corporation (the "Company"),  hereby
notifies the above-named Holder:

         (a) On _______________  (fill in date) five  Inconvertibility  Days had
occurred in a period of ten Trading Days and on such date  $__________  (fill in
amount)  of  principal  of the Note and the  related  interest,  if any,  became
inconvertible by reason of the occurrence of five Inconvertibility Days within a
period of ten consecutive Trading Days.

         (b) The five  Inconvertibility  Days  covered  by this  Notice  and the
applicable Conversion Price on each such day are as follows:

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

         (2) The  Inconvertibility  Days  referred to in this  Notice  relate to
(check (a) or (b)):


|_|      (a) Maximum Share Amount Inconvertibility

|_|      (b) Registration Restriction Inconvertibility

         (3) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.

                                       B-1

<PAGE>


Date _________________________                            SUGEN, INC.



                                                          By____________________

                                       B-2

<PAGE>


                                                                       Exhibit C

                         HOLDER INCONVERTIBILITY NOTICE
         (Section 2.4(b) of 5% Senior Custom Convertible Note due 2000)

TO:      SUGEN, INC.

         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"), the undersigned (the "Holder"),  hereby notifies SUGEN, Inc.,
a Delaware corporation (the "Company"):

         (a) On  ____________  (fill in  date)  five  Inconvertibility  Days had
occurred in a period of ten Trading Days and on such date $___________  (fill in
amount)  of  principal  of the Note and the  related  interest,  if any,  became
inconvertible by reason of the occurrence of five Inconvertibility Days within a
period of ten consecutive Trading Days.

         (b) The five  Inconvertibility  Days  covered  by this  Notice  and the
applicable Conversion Price on each such day are as follows:

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

____________________, ___________       $____________

         (2) The  Inconvertibility  Days  referred to in this  Notice  relate to
(check (a) or (b)):


|_|      (a) Maximum Share Amount Inconvertibility

|_|      (b) Registration Restriction Inconvertibility

         (3) If the following date and amounts are completed in this Notice, the
Holder hereby directs the Company to redeem the principal amount set forth below
(and the related interest) in accordance with Section 7(a) of the Certificate of
Designations set forth below:

                                       C-1

<PAGE>


         (a) Principal amount of Note to be redeemed: __________ (fill in)

         (b) On ______________  (fill in Redemption Date), the Company shall pay
the Holder the Redemption  Price of the portion  (which,  if applicable,  may be
all) of the Note to be redeemed of $____________.  The Redemption Price is equal
to the sum of (1) the product  obtained  by  multiplying  (A)(i)  $_____________
(fill in) of principal plus (ii) $____________ of accrued and unpaid interest on
such principal amount to such Redemption Date times (B) ______________% (fill in
applicable  Redemption  Percentage)  plus (2) $ of accrued  and  unpaid  Default
Interest (if any) to such Redemption Date.

         (4) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.


Date _________________________                     NAME OF HOLDER:

                                                   _____________________________


                                                   By___________________________
                                                      Title:

                                       C-1

<PAGE>


                                                                       Exhibit D

                           HOLDER REDEMPTION ELECTION
                       (Section 2.4(b) of 5% Senior Custom
                           Convertible Note due 2000)


TO:      SUGEN, INC.

         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"), the undersigned (the "Holder") hereby notifies SUGEN, Inc., a
Delaware corporation (the "Company"), that the Holder is exercising its right to
require the Company to redeem a portion  (which,  if applicable,  may be all) of
the Note as set forth below in  accordance  with Section  2.4(b) of the Note. On
_______________  (fill in Redemption Date), the Company shall pay the Holder the
Redemption Price of $________________.  The Redemption Price is equal to the sum
of (1) the product obtained by multiplying (A)(i) $________________ (fill in) of
principal  plus (ii)  $________________  of accrued and unpaid  interest on such
principal  amount to such Redemption Date times (B)  ________________%  (fill in
applicable  Redemption  Percentage)  plus (2)  $________________  of accrued and
unpaid Default Interest (if any) to such Redemption Date.

         (2) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.


Date                                               NAME OF HOLDER:

                                                   _____________________________


                                                   By___________________________

                                       D-1

<PAGE>


                                                                       Exhibit E

                           MANDATORY REDEMPTION WAIVER

         SUGEN,   Inc.,  a  Delaware   corporation  (the  "Company"),   and  the
undersigned  holder (the "Holder") of the Company's 5% Senior Custom Convertible
Note due 2000 (the "Note") hereby agree as follows:

         1. The  Company's  or the  Holder's  Inconvertibility  Notice  given on
________________  (the "Waiver  Commencement Date"), if any, is hereby rescinded
and the Note shall not be redeemed pursuant to Section 2.4 of the Note by reason
of such  Inconvertibility  Notice or any  inconvertibility of the Note which may
arise  pursuant to Section 2.4 of the Note during the period  ending on the date
set forth below in this Section 1 (the "Waiver Period").

         Date for end of Waiver Period: _______________________ , 19___

         2. If this Mandatory  Redemption  Waiver is given in connection  with a
Registration Restriction Inconvertibility,  promptly, but in no event later than
the date which is 15 days after the date of this  Mandatory  Redemption  Waiver,
the Company  shall file a  Registration  Statement  with the SEC relating to the
resale by the Holder of the number of Registrable  Securities (as defined in the
Note Purchase  Agreement) set forth below in this Section 2, which  Registration
Statement  may be  constituted  in any manner  which does not have the effect of
suspending  or  terminating  the  effectiveness  of  any  and  all  Registration
Statements filed by the Company pursuant to Section 8(b)(1) of the Note Purchase
Agreement or otherwise with respect to the  Registrable  Securities  which names
the Holder as a selling  stockholder,  and shall thereafter use its best efforts
to  obtain  effectiveness  of such  Registration  Statement.  Such  Registration
Statement  shall in all respects be deemed a Registration  Statement (as defined
in the Note).

         Number of Registrable Securities: ________________

         3. If the Company shall default in the  performance of its  obligations
set forth herein, this Mandatory  Redemption Waiver shall cease to be of further
force and effect and the  rights,  liabilities  and  obligations  of the parties
shall be  restored  to those  which  would have  existed in the  absence of this
Mandatory Redemption Waiver.

         4.  This  Agreement  shall  be  governed  by the  laws of the  State of
California. Capitalized terms used herein and not otherwise defined herein shall
have the respective meanings provided in the Note.

                                       E-1

<PAGE>


         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective  officers or other  representatives  thereunto
duly authorized as of the respective dates set forth below.

                                                   SUGEN, INC.



                                                   By___________________________
                                                         Title:

                                                   Date:________________________


                                                   NAME OF HOLDER:

                                                   _____________________________



                                                   By___________________________
                                                         Title:

                                                   Date:________________________

                                       E-2

<PAGE>


                                                                       Exhibit F

                                 COMPANY NOTICE
         (Section 5.2(a) of 5% Senior Custom Convertible Note due 2000)

TO:______________________
        (Name of Holder)


         (1) A Repurchase  Event  described in the 5% Senior Custom  Convertible
Note due  2000  (the  "Note")  of  SUGEN,  Inc.,  a  Delaware  corporation  (the
"Company"),  occurred  on  ______________,  ___________.  As a  result  of  such
Repurchase  Event,  the Holder is  entitled to exercise  its  repurchase  rights
pursuant to Section 5.2 of the Note.

         (2) The  Holder's  repurchase  right  must be  exercised  on or  before
______________, __________.

         (3) At or before the date set forth in the preceding paragraph (2), the
Holder must:

     (a) deliver to the Company a Holder Notice, in the form attached as Exhibit
G to the Note; and

     (b) the Note,  duly  endorsed for transfer to the Company of the portion of
the principal amount to be repurchased.

         (4) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.


Date _________________________                    SUGEN, INC.



                                                  By____________________________
                                                      Title:

                                       F-1

<PAGE>


                                                                       Exhibit G

                                  HOLDER NOTICE
         (Section 5.2(b) of 5% Senior Custom Convertible Note due 2000)

TO:      SUGEN, INC.

         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"), the undersigned Holder hereby elects to exercise its right to
require  repurchase  by the Company  pursuant  to Sections  5.2(a) and 5.2(b) of
$______________  of the  Note,  equal  to the sum of  $______________  principal
amount of the Note,  $______________  of  accrued  and unpaid  interest  on such
principal  amount and $ of Default  Interest on such interest at the  Repurchase
Price provided in the Note.

         (2) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.


     Date:                                           NAME OF HOLDER:





                                                     By_________________________
                                                        Signature of  Registered
                                                        Holder  (Must be  signed
                                                        exactly as name  appears
                                                        in the Note.)

                                       G-1

<PAGE>


                                                                       Exhibit H

                      HOLDER REGISTRATION REPURCHASE NOTICE
           (Section 5.3 of 5% Senior Custom Convertible Note due 2000)

                                 TO: SUGEN, INC.

         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000 (the "Note"), the undersigned Holder hereby elects to exercise its right to
require  repurchase by the Company pursuant to Section 5.3 of $______________ of
the  Note,  equal to the sum of  $______________  principal  amount of the Note,
$______________  of accrued  and unpaid  interest on such  principal  amount and
$______________  of  Default  Interest  on  such  interest  at the  Registration
Repurchase Price provided in the Note.

         (2) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.


     Date: ___________________                       NAME OF HOLDER:





                                                     By_________________________
                                                        Signature of  Registered
                                                        Holder  (Must be  signed
                                                        exactly as name  appears
                                                        in the Note.)

                                       H-1

<PAGE>


                                                                       Exhibit I

                        HOLDER NOTICE OF FINAL CONVERSION
                  OF 5% SENIOR CUSTOM CONVERTIBLE NOTE DUE 2000

TO:      SUGEN, INC.


         (1) Pursuant to the terms of the 5% Senior Custom  Convertible Note due
2000  (the  "Note"),   issued  by  SUGEN,  Inc.,  a  Delaware  corporation  (the
"Company"), the undersigned Holder of the Note hereby elects (check one)


|_|      To  convert  the  principal  amount of the  Note,  accrued  and  unpaid
         interest on such principal amount and Default Interest on such interest
         into shares of Common Stock of the Company which is  outstanding on the
         Maturity Date.


|_|      To receive a Final  Maturity  Note in the form  attached to the Note as
         Exhibit J in accordance with Section 6.2 of the Note.

         (2) In connection with this certificate the Holder hereby represents to
the Company as follows:

         (a) If the Holder hereby elects to exercise its conversion  rights,  it
will  not  violate  the  provisions  of  Section  2.1 of the  Note  relating  to
beneficial ownership in excess of 4.9% of the Common Stock.

         (b) If the Holder has selected conversion of the Note and the shares of
Common Stock issuable upon conversion of the Note have not been registered under
the  Securities  Act of 1933,  as amended  (the  "1933  Act"),  the  undersigned
represents  and warrants that (i) such shares of Common Stock are being acquired
for the account of the undersigned  for  investment,  and not with a view to, or
for  resale  in  connection  with,  the  distribution   thereof,  and  that  the
undersigned  has no present  intention of  distributing or reselling such shares
and (ii) the undersigned is an "accredited  investor" as defined in Regulation D
under the 1933 Act. The  undersigned  further  agrees that (A) such shares shall
not be sold or  transferred  unless  either  (i)  they  first  shall  have  been
registered  under the 1933 Act and applicable  state securities laws or (ii) the
Company  first  shall  have been  furnished  with an  opinion  of legal  counsel
reasonably  satisfactory to the Company to the effect that such sale or transfer
is exempt from the

                                       I-1

<PAGE>


registration  requirements  of the  1933  Act  and (B)  until  such  shares  are
registered  under  the  1933  Act,  the  Company  may  place  a  legend  on  the
certificate(s)  for  the  shares  to  that  effect  and  place  a  stop-transfer
restriction in its records relating to the shares.

         (c) It is an "accredited  investor" as that term is defined in Rule 501
of Regulation D under the 1933 Act by reason of Rule 501(a)(3).

         (3) Capitalized terms used herein and not otherwise defined herein have
the respective meanings provided in the Note.

                                       I-2

<PAGE>


                                                NAME OF HOLDER:

Date _________________________



                                                By______________________________


                                                Title:__________________________

                                       I-3

<PAGE>


                                                                       Exhibit J

THIS FINAL  MATURITY NOTE HAS NOT BEEN  REGISTERED  UNDER THE  SECURITIES ACT OF
1933,  AS AMENDED  (THE "1933  ACT") OR ANY STATE  SECURITIES  LAWS.  THIS FINAL
MATURITY  NOTE  HAS  BEEN  ACQUIRED  FOR  INVESTMENT  ONLY  AND MAY NOT BE SOLD,
TRANSFERRED  OR ASSIGNED IN THE ABSENCE OF  REGISTRATION  OF THE RESALE  THEREOF
UNDER THE 1933 ACT OR AN  OPINION OF COUNSEL  REASONABLY  SATISFACTORY  IN FORM,
SCOPE AND SUBSTANCE TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.  THIS
FINAL MATURITY NOTE MAY NOT BE TRANSFERRED EXCEPT AS PROVIDED IN SECTION 3.7.

                                   SUGEN, INC.

                               FINAL MATURITY NOTE

New York, New York                                                     $________
            , 2005                                              No.

         FOR VALUE RECEIVED,  SUGEN, INC., a Delaware  corporation  (hereinafter
called the  "Company"),  hereby  promises to pay to ,  [Address],  or registered
assigns (the "Holder") or order, the sum of Dollars ($ ), on [before signing the
Final Maturity Note,  insert month and day of the Note's Issuance  Date],  2005,
and to pay  interest  on the  unpaid  principal  balance  hereof  at the rate of
thirteen  and three  quarters  percent  (13.75%) per annum from the date hereof,
until the same becomes due and payable, whether at maturity or upon acceleration
or by prepayment  or  otherwise.  Any amount of principal of or interest on this
Final  Maturity  Note which is not paid when due shall bear interest at the rate
of fifteen  percent  (15%) per annum from the due date thereof until the same is
paid  ("Default  Interest").  Interest  shall be  payable on the 1st day of each
April and October,  commencing on April 1, 2001,  and at maturity (the "Interest
Payment  Dates").  Interest on this Final Maturity Note shall be computed on the
basis of a 360-day year of 12 30-day months and actual days elapsed.

         All payments of principal of and interest on this Final  Maturity  Note
shall be made in lawful money of the United States of America, or, at the option
of the  Company  and  subject to the  provisions  of this Final  Maturity  Note,
interest  payable on the Interest  Payment Dates may be paid in whole or in part
in fully paid and  nonassessable  shares of Common Stock, $.01 par value, or any
shares of capital stock and related  rights of the Company into which such stock
shall  hereafter  be changed or  reclassified  (the  "Common  Stock").  All cash
payments shall be made by wire transfer of immediately  available  funds to such
account as the Holder may from

                                       J-1

<PAGE>


time to time  designate by written  notice in accordance  with the provisions of
this Final Maturity Note.  Whenever any amount  expressed to be due by the terms
of this Final  Maturity  Note is due on any day which is not a business day, the
same shall instead be due on the next succeeding day which is not a business day
and,  in the case of any  Interest  Payment  Date which is not the date on which
this Final  Maturity Note is paid in full, the extension of the due date thereof
shall not be taken  into  account  for  purposes  of  determining  the amount of
interest  due on such  date.  As used in this  Final  Maturity  Note,  the  term
"business  day"  shall mean any day other  than a  Saturday,  Sunday or a day on
which commercial banks in The City of New York are authorized or required by law
or executive order to remain closed.

         The  obligations  of the Company  under this Final  Maturity Note shall
rank in right of payment on a parity with all other  unsubordinated  obligations
of the Company for  indebtedness  for borrowed  money or the  purchase  price of
property.  This Final  Maturity  Note is issued  pursuant to a 5% Senior  Custom
Convertible Note due 2000 issued by the Company (the "Note").

         The following terms shall apply to this Final Maturity Note:


                                    ARTICLE I

                      PREPAYMENT; INTEREST IN COMMON STOCK

         1.1  Prepayment.  The Company shall have the right to prepay this Final
Maturity Note in whole at any time or in any part from time to time.

         1.2  Issuance  of  Common  Stock in Lieu of Cash  Interest.  (a) If the
Company  exercises  its  option  to make a payment  of  interest  on this  Final
Maturity  Note  wholly or partly in  shares of Common  Stock  (herein  sometimes
called the "Stock Payment Option"),  the issuance of shares of Common Stock upon
such  exercise of the Stock  Payment  Option shall have been  authorized  by the
Board of Directors of the Company.

         (b) The Company  shall not be permitted  to exercise the Stock  Payment
Option with respect to any payment of interest on this Final Maturity Note if:

         (i) the  number  of shares of Common  Stock  authorized,  unissued  and
     unreserved  for  all  purposes,  or  held  in the  Company's  treasury,  is
     insufficient  to pay the  portion  of such  interest  to be paid in  Common
     Stock;

         (ii) the issuance or delivery of shares of Common Stock pursuant to

                                       J-2

<PAGE>


the Stock Payment Option or the public resale of such shares by the Holder would
require  registration  with or approval of any governmental  authority under any
law or regulation,  and such  registration  or approval has not been effected or
obtained or is not in effect and the  Registration  Statement is unavailable for
use by the Holder for the resale of such shares;

         (iii) the  shares of Common  Stock to be issued  upon  exercise  of the
     Stock Payment Option have not been  authorized  for listing,  upon official
     notice of  issuance,  on the  principal  securities  exchange  on which the
     Common Stock is then listed and traded;

         (iv) the Computed Price is less than the par value of the Common Stock;

         (v) an Event  of  Default  (as  defined  herein)  has  occurred  and is
     continuing; or

         (vi) the Common  Stock is neither (i) listed or admitted for trading on
     a national  securities  exchange  nor (ii)  quoted on the  Nasdaq  National
     Market.

         (c) If the Stock Payment Option is elected, the Company shall issue and
dispatch or cause to be  dispatched to the Holder one or more  certificates  for
the aggregate  number of whole shares of Common Stock determined by dividing the
per share Computed Price of the Common Stock on the applicable  Interest Payment
Date into the total amount of lawful money of the United States of America which
the Holder  would  receive if the  aggregate  amount of  interest  on this Final
Maturity  Note which is being paid in shares of Common  Stock were being paid in
such  lawful  money;  provided,  however,  that if in  connection  with any such
election  the Company  shall have failed to deliver  the  appropriate  number of
shares of Common  Stock to the  Holder  within  three  business  days  after the
applicable  Interest Payment Date, then the Company shall not be entitled to use
the Stock  Payment  Option in respect of such Interest  Payment Date,  such cash
interest  shall be  immediately  due and payable  and the Company  shall pay the
interest for such Interest  Payment Date in cash with Default  Interest,  at the
rate  provided in this Note,  from such  Interest  Payment  Date until paid.  No
fractional  shares will be issued in payment of interest on this Final  Maturity
Note. In lieu thereof,  the Company may issue a number of shares of Common Stock
which reflects a rounding up to the next whole number or may pay lawful money of
the United States of America.  The shares of Common Stock issued or to be issued
by the Company in payment of interest on this Final  Maturity Note are sometimes
referred to herein as the "Payment Shares."

         (d) If the Company exercises the Stock Payment Option with respect to a

                                       J-3

<PAGE>


payment of interest on this Final  Maturity  Note,  the Company shall deliver to
the Holder,  on or prior to the date on which Payment Shares for such payment of
interest on this Final Maturity Note are to be received by the Holder, a Company
Certificate  setting forth (i) the total amount of the interest payment to which
the Holder is entitled,  (ii) the portion of the interest  payment being made in
Payment Shares, (iii) the number of Payment Shares allocable to such payment, as
calculated  pursuant to this Section 1.2,  (iv) any rounding  adjustment to such
number or any payment  necessary to be made  pursuant to Section  1.2(c),  (v) a
brief  statement  of the facts  requiring  such  adjustment,  (vi) the number of
Payment  Shares  issuable  with  respect to each $100 of  interest on this Final
Maturity Note after such adjustment and (vii) a brief statement that none of the
conditions  set forth in  Section  1.2(b) has  occurred  and is  existing.  Such
Company  Certificate shall be accompanied by the certificates,  each duly issued
in the  name of the  Holder,  representing  the  Payment  Shares.  Such  Company
Certificate  shall be conclusive  evidence of the correctness of the calculation
of the number of Payment Shares  allocable to the payments to which such Company
Certificate  relates and of any adjustments to such number made pursuant to this
Section 1.2 in the  absence of manifest  error.  In  addition,  on or before the
pertinent  payment  date,  the Company  shall cause the  transfer  agent for the
Common  Stock to prepare  and issue the  certificates  representing  the Payment
Shares in the name of the Holder before being so delivered by the Company.

         (e) The Payment Shares,  when issued pursuant to and in compliance with
this Section 1.2,  shall be, and for all purposes shall be deemed to be, validly
issued,  fully paid and  nonassessable  shares of Common Stock; the issuance and
delivery thereof is in all respects hereby authorized; and the issuance thereof,
together with lawful money of the United States of America, if any, paid in lieu
of fractional  shares of such Common Stock,  will be, and for all purposes shall
be deemed to be, in full discharge and satisfaction of the Company's  obligation
to pay the interest on this Final  Maturity  Note to which such  Payment  Shares
relate.

         (f) As used in this Final Maturity Note, the following terms shall have
the meanings provided herein:

         (1) "Company  Certificate" means a certificate of the Company signed by
     an Officer.

         (2) "Computed Price" for any date means  arithmetic  average of the per
     share  Trading  Price  during the  Measurement  Period with respect to such
     date.

         (3) "Measurement Period" means, with respect to any date, the period of
     five consecutive trading days ending three trading days prior to such date.

         (4)  "Officer"  means the  Chairman of the Board,  the Chief  Executive
     Officer,

                                       J-4

<PAGE>


     the President,  the Chief Operating  Officer,  any Senior Vice President or
     the Chief Financial Officer of the Company.

         (5) "Other Final Maturity Notes" means the several Final Maturity Notes
     issued by the Company pursuant to the Other Notes.

         (6) "Other Notes" means the several 5% Senior Custom  Convertible Notes
     due 2000 issued by the Company.

         (7) "Trading  Day" means a day on which either the national  securities
     exchange or Nasdaq which then constitutes the principal  securities  market
     for the Common Stock is open for general trading.

         (8)  "Trading  Price" on any date means the  closing  bid price for one
     share of the Common Stock on such date, on the first  applicable  among the
     following:  (a) the  national  securities  exchange  on which the shares of
     Common Stock are listed which  constitutes the principal  securities market
     for the Common Stock or (b) the Nasdaq National  Market,  in either case as
     reported by Bloomberg,  L.P. (subject to equitable  adjustment from time to
     time on terms  reasonably  acceptable  to the Holder for (i) stock  splits,
     (ii) stock dividends, (iii) combinations, (iv) capital reorganizations, (v)
     issuance to all  holders of Common  Stock of rights or warrants to purchase
     shares of Common  Stock at a price per share  less than the  Trading  Price
     which would otherwise be applicable,  (vi) the  distribution by the Company
     to all holders of Common Stock of evidences of  indebtedness of the Company
     or cash (other than regular quarterly cash dividends),  (vii) tender offers
     by the Company or any  subsidiary  of the Company or other  repurchases  of
     shares of Common Stock in one or more transactions  which,  individually or
     in the  aggregate,  result in the  purchase of more than ten percent of the
     Common Stock  outstanding  and (viii) similar events relating to the Common
     Stock,  in each such  case  which  occur  during a  particular  Measurement
     Period).

         (9)  "Transaction  Documents" means this Final Maturity Note, the Note,
     the Note  Purchase  Agreement  and the other  agreements,  instruments  and
     documents contemplated hereby and thereby.


                                   ARTICLE II

                                EVENTS OF DEFAULT

         If any of the following events of default (each, an "Event of Default")
     shall occur:

                                       J-5

<PAGE>


         2.1 Failure to Pay Principal or Interest.  The Company fails (a) to pay
the  principal  hereof when due,  whether at  maturity,  upon  redemption,  upon
acceleration  or otherwise or (b) to pay any installment of interest hereon when
due and, in the case of this clause (b) of this  Section 2.1 only,  such failure
continues for a period of ten (10) business days after the due date thereof;

         2.2 Breach of Covenant.  The Company breaches any material  covenant or
other  material  term or  condition of this Final  Maturity  Note (other than as
specifically  provided in Section 2.1 hereof),  and such breach  continues for a
period of twenty (20) days after written  notice thereof to the Company from the
Holder or within 60 days  after  delivery  of such  notice if and only if,  such
default is reasonably capable of cure and during such 60-day period, the Company
has been  diligently  taking action to cure such default and such cure cannot be
completed within such 20-day period;

         2.3 Breach of  Representations  and Warranties.  Any  representation or
warranty  of  the  Company  made  herein  or  in  any  agreement,  statement  or
certificate  given  in  writing  pursuant  hereto  or  in  connection   herewith
(including,  without limitation,  the Note Purchase Agreement) shall be false or
misleading in any material respect when made;

         2.4  Certain  Voluntary  Proceedings.  The  Company or any  significant
subsidiary  (as defined in Section  1.02(w) of Regulation  S-X of the Securities
and Exchange Commission) of the Company shall commence a voluntary case or other
proceeding seeking  liquidation,  reorganization or other relief with respect to
itself or its debts under any bankruptcy, insolvency or other similar law now or
hereafter  in  effect  or  seeking  the  appointment  of  a  trustee,  receiver,
liquidator, custodian or other similar official of it or any substantial part of
its property,  or shall consent to any such relief or to the  appointment  of or
taking  possession  by  any  such  official  in an  involuntary  case  or  other
proceeding  commenced  against  it, or shall make a general  assignment  for the
benefit of  creditors,  or shall fail  generally to pay its debts as they become
due or shall admit in writing its  inability  generally to pay its debts as they
become due;

         2.5  Certain  Involuntary  Proceedings.  An  involuntary  case or other
proceeding shall be commenced against the Company or any significant  subsidiary
of the Company seeking liquidation,  reorganization or other relief with respect
to it or its debts under any bankruptcy,  insolvency or other similar law now or
hereafter  in  effect  or  seeking  the  appointment  of  a  trustee,  receiver,
liquidator, custodian or other similar official of it or any substantial part of
its  property,  and such  involuntary  case or  other  proceeding  shall  remain
undismissed and unstayed for a period of sixty (60) consecutive days;

         2.6 Judgments.  Any court of competent  jurisdiction shall enter one or
more final judgments against the Company or any subsidiary of the Company or any
of their

                                      J-6

<PAGE>


respective  properties  or other  assets  in an  aggregate  amount  in excess of
$1,500,000,  which is not  vacated,  bonded,  stayed,  discharged,  satisfied or
waived for a period of thirty (30) consecutive days; or

         2.7 Default Under Other  Agreements.  (a) The Company or any subsidiary
shall (i) default in any payment with respect to any  indebtedness  for borrowed
money  (other  than  this  Final  Maturity  Note)  which   indebtedness  has  an
outstanding principal amount in excess of $2,000,000  individually or $5,000,000
in the  aggregate  for the  Company and its  subsidiaries,  beyond the period of
grace,  if any,  provided  in the  instrument  or  agreement  under  which  such
indebtedness was created or (ii) default in the observance or performance of any
agreement,  covenant or condition relating to any such indebtedness or contained
in any instrument or agreement evidencing,  securing or relating thereto, or any
other event shall occur or condition exist, the effect of which default or other
event or  condition  is to cause,  or to permit  the  holder or  holders of such
indebtedness  (or a trustee  or agent on behalf of such  holder or  holders)  to
cause, any such indebtedness to become due prior to its stated maturity and such
default or event shall continue beyond the period of grace, if any,  provided in
the  instrument or agreement  under which such  indebtedness  was created (after
giving effect to any consent or waiver obtained and then in effect  thereunder);
or (b) any such indebtedness of the Company or any of its subsidiaries shall, in
accordance with its terms, be declared to be due and payable,  or required to be
prepaid  other than by a regularly  scheduled or required  payment  prior to the
stated maturity thereof;

then upon the  occurrence  and during the  continuation  of any Event of Default
specified in Section 2.1,  2.2,  2.3, 2.6 or 2.7 at the option of the Holder the
Company  shall,  and upon the  occurrence  of any Event of Default  specified in
Section 2.4 or 2.5, the Company shall,  pay to the Holder an amount equal to the
sum of (A) the outstanding principal amount of this Final Maturity Note plus (B)
accrued and unpaid interest on such principal amount to the date of payment plus
(C) accrued and unpaid Default  Interest,  if any, on the amount  referred to in
the immediately preceding clause (B) at the rate provided in this Final Maturity
Note to the date of  payment  and all  other  amounts  payable  hereunder  shall
immediately become due and payable,  all without demand,  presentment or notice,
all of which hereby are expressly  waived,  together with all costs,  including,
without limitation, legal fees and expenses, of collection, and the Holder shall
be entitled to exercise  all other  rights and  remedies  available at law or in
equity.


                                   ARTICLE III

                                  MISCELLANEOUS

         3.1 Failure or Indulgency  Not Waiver.  No failure or delay on the part
of the Holder in the exercise of any power,  right or privilege  hereunder shall
operate as a waiver

                                       J-7

<PAGE>


thereof,  nor shall any single or partial  exercise of any such power,  right or
privilege  preclude  other or further  exercise  thereof or of any other  right,
power or privileges.  All rights and remedies existing  hereunder are cumulative
to, and not exclusive of, any rights or remedies otherwise available.

         3.2 Notices.  Any notice herein required or permitted to be given shall
be in writing and may be personally  served,  sent by telephone  line  facsimile
transmission  or delivered by courier or sent by United States mail and shall be
deemed to have been given upon receipt if personally  served,  sent by telephone
line  facsimile  transmission  or sent by courier or three (3) days after  being
deposited  in the United  States  mail,  certified,  with  postage  pre-paid and
properly addressed, if sent by mail. For the purposes hereof, the address of the
Holder shall be as shown on the records of the Company (telephone line facsimile
transmission number (_)______-_______ ); and the address of the Company shall be
351  Galveston  Drive,  Redwood  City,  California  94063-4720  Attention:  Vice
President, Finance (telephone line facsimile transmission number (650) 306-4016.
A copy of any notice to the Company pursuant to this Note shall also be provided
to Cooley  Godward  LLP,  3000 El Camino  Real,  Palo  Alto,  California  94306,
Attention:   Brian  Cunningham  and  Suzanne  Sawochka  Hooper  (telephone  line
facsimile  transmission  number (650)  857-0663).  The Holder or the Company may
change the  address  for  service  by service of written  notice to the other as
herein provided.

         3.3  Amendment  Provision.  The  term  "Final  Maturity  Note"  and all
reference  thereto,  as  used  throughout  this  instrument,   shall  mean  this
instrument as originally executed, or if later amended or supplemented,  then as
so amended or supplemented.

         3.4  Assignability.  This Final Maturity Note shall be binding upon the
Company and its successors and assigns, and shall inure to the benefit of and be
binding upon the Holder and its successors and permitted assigns.

         3.5  Certain  Expenses.  The Company  shall pay on demand all  expenses
incurred by the Holder,  including reasonable attorneys' fees and expenses, as a
consequence  of, or in connection  with, (x) any default or breach of any of the
Company's  obligations  set  forth  in the  Transaction  Documents  and  (y) the
enforcement or  restructuring  of any right of,  including the collection of any
payments due, the Holder under the Transaction  Documents,  including any action
or proceeding  relating to such  enforcement  or any order,  injunction or other
process seeking to restrain the Company from paying any amount due the Holder.

         3.6 Governing  Law.  This Final  Maturity Note shall be governed by the
internal laws of the State of  California,  without  regard to the principles of
conflict of laws.

         3.7 Transfer of Final Maturity Note. This Note has not been and is not

                                       J-8

<PAGE>


being  registered  under the provisions of the 1933 Act or any state  securities
laws and  this  Note  may not be  transferred  unless  (1) the  transferee  is a
Permitted  Transferee  and (2) the Holder shall have delivered to the Company an
opinion of counsel,  reasonably satisfactory in form, scope and substance to the
Company,  to the  effect  that  this  Note may be sold or  transferred  pursuant
without  registration  under  the 1933  Act.  Prior to any such  transfer,  such
transferee shall have represented in writing to the Company that such transferee
has  requested  and received  from the Company all  information  relating to the
business,  properties,  operations,  condition (financial or other),  results of
operations or prospects of the Company deemed relevant by such transferee;  that
such  transferee  has been  afforded  the  opportunity  to ask  questions of the
Company  concerning  the  foregoing  and has had the  opportunity  to obtain and
review the Registration  Statement and the prospectus included therein,  each as
amended or  supplemented  to the date of  transfer to such  transferee,  and the
reports and other  information  concerning the Company which at the time of such
transfer  have been filed by the Company  with the SEC  pursuant to the 1934 Act
and which are  incorporated  by reference in such  prospectus  as of the date of
such transfer. "Permitted Transferee" means any person who is (1) an "accredited
investor"  as defined in  Regulation D under the 1933 Act and (2) a Person which
(A) has the same  investment  adviser as an Investor of the holder of any of the
Other Notes,  (B) has an investment  adviser which is under common  control with
the investment adviser to an Investor or the holder of any of the Other Notes or
(C) is an Affiliate of any Investor of the holder of any Other Note.

                                       J-9

<PAGE>


         IN WITNESS WHEREOF,  the Company has caused this Final Maturity Note to
be signed in its name by its duly authorized  officer on the day and in the year
first above written.

                                                          SUGEN, INC.



                                                          By
                                                            Name:
                                                            Title:

                                      J-10




                                    Annex IV
                                       to
                                  Note Purchase
                                    Agreement

THIS  SECURITY  HAS NOT BEEN  REGISTERED  UNDER  THE  SECURITIES  ACT OF 1933 OR
APPLICABLE  STATE  SECURITIES  LAWS  AND  MAY NOT BE  SOLD,  OFFERED  FOR  SALE,
TRANSFERRED,  PLEDGED OR  OTHERWISE  DISPOSED  OF UNLESS IT HAS BEEN  REGISTERED
UNDER  THOSE  LAWS OR UNLESS  THE  COMPANY  HAS  RECEIVED  AN OPINION OF COUNSEL
SATISFACTORY TO IT THAT AN EXEMPTION FROM REGISTRATION  UNDER EACH OF THOSE LAWS
IS AVAILABLE.

THIS  WARRANT  IS ISSUED  PURSUANT  TO A NOTE  PURCHASE  AGREEMENT,  DATED AS OF
SEPTEMBER __, 1997,  BY AND BETWEEN THE COMPANY AND THE ORIGINAL  HOLDER OF THIS
WARRANT,  AS AMENDED FROM TIME TO TIME,  AND THE HOLDER OF THIS WARRANT AND THIS
WARRANT ARE SUBJECT TO CERTAIN OF THE TERMS OF THE NOTE PURCHASE AGREEMENT.

THIS WARRANT MAY NOT BE TRANSFERRED EXCEPT AS PROVIDED IN
SECTION 17.

No.                                   Right to Purchase _______ Shares of Common
                                      Stock of SUGEN, Inc.


                                   SUGEN, INC.

                          Common Stock Purchase Warrant


         SUGEN, INC., a Delaware  corporation (the "Company"),  hereby certifies
that, for value received,  [NAME OF BUYER] or registered assigns (the "Holder"),
is entitled,  subject to the terms set forth below, to purchase from the Company
at any time or from time to time after the date  hereof,  and before  5:00 p.m.,
New York City time, on the Expiration  Date (as  hereinafter  defined),  _______
fully paid and  nonassessable  shares of Common  Stock at a  purchase  price per
share equal to the Purchase Price (as hereinafter  defined).  The number of such
shares of Common  Stock and the  Purchase  Price are  subject to  adjustment  as
provided in this Warrant.

         As used  herein the  following  capitalized  terms,  unless the context
otherwise requires, have the following respective meanings:

                                      IV-1

<PAGE>


         "Affiliate"  means,  with respect to any Person,  any other Person that
directly,  or  indirectly  through  one or  more  intermediaries,  controls,  is
controlled by or under common control with the subject  Person.  For purposes of
the term  "Affiliate",  the term "control"  (including the terms  "controlling",
"controlled by" and "under common control with") means the possession, direct or
indirect, of the power to direct or to cause the direction of the management and
policies of a Person,  whether through the ownership of securities,  by contract
or otherwise.

         "Aggregated Person" means a Person whose beneficial ownership of shares
of Common Stock would be aggregated  with the Holder's  beneficial  ownership of
shares of Common  Stock for  purposes of Section  13(d) of the  Exchange Act and
Regulation 13D-G thereunder.

         "Business Day" means a day on which the New York Stock Exchange is open
for trading of securities.

         "Common Stock" includes the Company's  Common Stock, par value $.01 per
share,  and the related  Preferred Share Purchase Rights (and any similar rights
issued with respect to the Common Stock) as  authorized on the date hereof,  and
any other  securities  into which or for which the Common  Stock or the  related
Preferred  Share Purchase  Rights (and any similar rights issued with respect to
the  Common  Stock)  may  be  converted  or  exchanged  pursuant  to a  plan  of
recapitalization, reorganization, merger, sale of assets or otherwise.

         "Company"  shall include  SUGEN,  Inc. and any  corporation  that shall
succeed to or assume the obligation of SUGEN, Inc.  hereunder in accordance with
the terms hereof.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended.

         "Expiration Date" means [INSERT MONTH AND DAY OF CLOSING DATE], 2000.

         "Note Purchase Agreement" means the Note Purchase  Agreement,  dated as
of September  _____________,  1997,  by and between the Company and the original
Holder of this Warrant.

         "Notes" means the several 5% Senior Custom  Convertible  Notes due 2000
issued by the Company pursuant to the Note Purchase Agreement and the Other Note
Purchase Agreements.

         "Other  Note  Purchase  Agreements"  means the  several  Note  Purchase
Agreements,  dated as of the date of the Note  Purchase  Agreement,  between the
Company and the several buyers named therein.

                                      IV-2

<PAGE>


         "Other  Securities" means any stock (other than Common Stock) and other
securities of the Company or any other Person which the Holder at any time shall
be entitled to receive, or shall have received, on the exercise of this Warrant,
in lieu of or in  addition  to  Common  Stock,  or which  at any  time  shall be
issuable or shall have been issued in exchange for or in  replacement  of Common
Stock or Other Securities pursuant to Section 4.

         "Permitted  Transferee"  means  any  person  who is (1) an  "accredited
investor" as defined in Regulation D under the  Securities  Act and (2) a Person
which (A) has the same investment  adviser as the Holder or the holder of any of
the Notes, (B) has an investment  adviser which is under common control with the
investment  adviser to the Holder or the holder of any of the Notes or (C) is an
Affiliate of the Holder or the holder of any of the Notes.

         "Person"  means  an  individual,   partnership,   corporation,  limited
liability  company,  trust or incorporated  organization,  and a government or a
governmental agency or political subdivision.

         "Preferred  Share Purchase  Rights" means the Preferred  Share Purchase
Rights  issued or  issuable  pursuant  to the Rights  Agreement  (or any similar
rights hereafter issued by the Company with respect to the Common Stock).

         "Purchase  Price" means  $16.74,  subject to  adjustment as provided in
this Warrant.

         "Rights  Agreement" means the Rights  Agreement,  dated as of August 1,
1995,  by and  between the Company and Boston  EquiServe,  as Rights  Agent,  as
amended from time to time in accordance with its terms.

         "SEC" means the Securities and Exchange Commission.

         "Securities Act" means the Securities Act of 1933, as amended.

         1. Exercise of Warrant.

         1.1  Exercise.  (a) This Warrant may be exercised by the Holder in full
or in part at any time or from time to time during the exercise period specified
in the first paragraph hereof until the Expiration Date by (x) surrendering this
Warrant to the  Company,  (y)  giving a  subscription  form in the form  annexed
hereto (duly executed by the Holder) to the Company,  and (z) making payment, in
cash or by certified or official bank check payable to the order of the Company,
or by wire  transfer of funds to the account of the Company,  in either case, in
the amount  obtained  by  multiplying  (a) the number of shares of Common  Stock
designated by the Holder in the subscription form by (b) the Purchase Price then
in effect. On any partial exercise

                                      IV-3

<PAGE>


the Company will forthwith  issue and deliver to or upon the order of the Holder
a new Warrant or  Warrants  of like  tenor,  in the name of the Holder or as the
Holder  (upon  payment  by the  Holder of any  applicable  transfer  taxes)  may
request,  providing  in the  aggregate  on the  face or  faces  thereof  for the
purchase  of the  number of shares of Common  Stock for which  such  Warrant  or
Warrants may still be exercised.  The  subscription  form may be  surrendered by
telephone line facsimile  transmission to the telephone numbers shown thereon or
such other  numbers  for the Company or such  transfer  agent as shall have been
specified in writing to the Holder by the Company;  provided,  however,  that if
the  subscription  form is given to the  Company  by  telephone  line  facsimile
transmission the Holder shall send an original of such  subscription form to the
Company within ten Business Days after such subscription form is so given to the
Company.

         (b)  Notwithstanding  any other provision of this Warrant,  in no event
shall  the  Holder be  entitled  at any time to  purchase  a number of shares of
Common Stock on exercise of this Warrant in excess of that number of shares upon
purchase  of  which  the  sum of (1)  the  number  of  shares  of  Common  Stock
beneficially  owned by the Holder and all Aggregated  Persons (other than shares
of  Common  Stock  deemed  beneficially  owned  through  the  ownership  of  the
unexercised  portion of this Warrant and any of the  Company's 5% Senior  Custom
Convertible  Notes  due  2000  and  any  other  securities   containing  similar
restrictions  by the Holder and all  Aggregated  Persons)  and (2) the number of
shares of Common  Stock  issuable  upon  exercise of the portion of this Warrant
with respect to which the  determination  in this sentence is being made,  would
result in beneficial  ownership by the Holder and all Aggregated Persons of more
than 4.9% of the  outstanding  shares  of  Common  Stock.  For  purposes  of the
immediately  preceding  sentence,  beneficial  ownership  shall be determined in
accordance  with  Section  13(d)  of  the  Exchange  Act  and  Regulation  13D-G
thereunder,  except  as  otherwise  provided  in clause  (1) of the  immediately
preceding sentence.  For purposes of the second preceding sentence,  the Company
shall be  entitled to rely,  and shall be fully  protected  in  relying,  on any
statement or representation made by the Holder to the Company in connection with
a particular exercise of this Warrant, without any obligation on the part of the
Company to make any  inquiry or  investigation  or to examine its records or the
records of any transfer agent for the Common Stock.

         1.2 Net Issuance. Notwithstanding anything to the contrary contained in
Section 1.1, the Holder may elect to exercise this Warrant, in whole or in part,
by  receiving  shares  of  Common  Stock  equal to the net  issuance  value  (as
determined  below) of this Warrant,  or any part hereof,  upon surrender of this
Warrant to the  Company's  transfer  agent and  registrar  for the Common  Stock
together  with the  subscription  form  annexed  hereto  (duly  executed  by the
Holder), in which event the Company shall issue to the Holder a number of shares
of Common Stock computed using the following formula:

                                      IV-4

<PAGE>


                 X = Y (A-B)
                     _______
                        A

       Where:         X =      the number of shares of Common Stock to be issued
                               to the Holder

                      Y =      the number of shares of Common  Stock as to which
                               this Warrant is to be exercised

                      A =      the  current  fair  market  value of one share of
                               Common  Stock  calculated  as of the last trading
                               day  immediately  preceding  the exercise of this
                               Warrant

                      B =      the Purchase Price

         As used  herein,  current  fair  market  value of Common  Stock as of a
specified date shall mean with respect to each share of Common Stock the average
of the closing sale price of the Common Stock on the principal securities market
on which the  Common  Stock may at the time be listed  or, if there have been no
sales on any such  exchange  on such day,  the  average of the  highest  bid and
lowest asked prices on the principal  securities  market at the end of such day,
or,  if on such  day the  Common  Stock is not so  listed,  the  average  of the
representative bid and asked prices quoted in the Nasdaq Stock Market as of 4:00
p.m.,  New York City time,  or, if on such day the Common Stock is not quoted in
the Nasdaq  National  Market,  the average of the  highest bid and lowest  asked
price on such day in the  domestic  over-the-counter  market as  reported by the
National Quotation Bureau, Incorporated,  or any similar successor organization,
in each  such case  averaged  over a period of five  consecutive  Business  Days
consisting  of the day as of which the current  fair market  value of a share of
Common  Stock is being  determined  (or if such day is not a Business  Day,  the
Business Day next  preceding  such day) and the four  consecutive  Business Days
prior to such day. If on the date for which  current  fair market value is to be
determined the Common Stock is not listed on any  securities  exchange or quoted
on the Nasdaq National Market or the  over-the-counter  market, the current fair
market  value of Common  Stock  shall be the  highest  price per share which the
Company  could  then  obtain  from a willing  buyer (not a current  employee  or
director) for shares of Common Stock sold by the Company,  from  authorized  but
unissued  shares,  as  determined in good faith by the Board of Directors of the
Company,  unless prior to such date the Company has become  subject to a merger,
acquisition  or other  consolidation  pursuant  to which the  Company is not the
surviving party, in which case the current fair market value of the Common Stock
shall be deemed to be the value received by the holders of the Company's  Common
Stock for each share thereof pursuant to the Company's acquisition.

         2.  Delivery  of Stock  Certificates,  etc.,  on  Exercise.  As soon as
practicable  after the  exercise of this  Warrant,  and in any event  within ten
Business Days thereafter,  the Company at its expense  (including the payment by
it of any  applicable  issue or stamp taxes) will cause to be issued in the name
of and delivered to the Holder, or as the Holder (upon payment

                                      IV-5

<PAGE>


by the Holder of any  applicable  transfer  taxes) may direct,  a certificate or
certificates  for the  number of fully paid and  nonassessable  shares of Common
Stock (or  Other  Securities)  to which the  Holder  shall be  entitled  on such
exercise, in such denominations as may be requested by the Holder, plus, in lieu
of any fractional  share to which the Holder would  otherwise be entitled,  cash
equal to such  fraction  multiplied  by the then  current  fair market value (as
determined in accordance with  subsection 1.2) of one full share,  together with
any  other  stock  or other  securities  any  property  (including  cash,  where
applicable)  to which the Holder is  entitled  upon such  exercise  pursuant  to
Section 1 or otherwise.  Upon exercise of this Warrant as provided  herein,  the
Company's  obligation  to issue and deliver the  certificates  for Common  Stock
shall be absolute and  unconditional,  irrespective of the absence of any action
by the Holder to enforce  the same,  any waiver or consent  with  respect to any
provision hereof,  the recovery of any judgment against any Person or any action
to  enforce  the same,  any  failure  or delay in the  enforcement  of any other
obligation  of  the  Company  to  the  Holder,  or  any  setoff,   counterclaim,
recoupment,  limitation or  termination,  or any breach or alleged breach by the
Holder or any other Person of any  obligation to the Company or any violation or
alleged violation of law by the Holder or any other Person,  and irrespective of
any other  circumstance  which  might  otherwise  limit such  obligation  of the
Company to the Holder in connection with such exercise.  If the Company fails to
issue and deliver the  certificates  for the Common Stock to the Holder pursuant
to the  first  sentence  of this  paragraph  as and when  required  to do so, in
addition  to any other  liabilities  the Company  may have  hereunder  and under
applicable  law, the Company shall pay or reimburse the Holder on demand for all
out-of-pocket expenses including, without limitation, fees and expenses of legal
counsel incurred by the Holder as a result of such failure.

         3.   Adjustment   for  Dividends  in  Other  Stock,   Property,   etc.;
Reclassification, etc. In case at any time or from time to time, all the holders
of Common Stock (or Other Securities)  shall have received,  or (on or after the
record date fixed for the  determination  of  stockholders  eligible to receive)
shall have become entitled to receive, without payment therefor,

         (a) other or additional  stock or other  securities or property  (other
     than cash) by way of dividend, or

         (b) any cash (excluding  cash dividends  payable solely out of earnings
     or earned surplus of the Company), or

         (c)  other  or  additional   stock  or  other  securities  or  property
     (including   cash)  by  way  of   spin-off,   split-up,   reclassification,
     recapitalization, combination of shares or similar corporate rearrangement,

other than additional shares of Common Stock (or Other  Securities)  issued as a
stock dividend or in a stock-split (adjustments in respect of which are provided
for in Section 5), then and in each such case the Holder, on the exercise hereof
as  provided  in Section 1, shall be entitled to receive the amount of stock and
other securities and property (including cash in the cases

                                      IV-6

<PAGE>


referred  to in  subdivisions  (b) and (c) of this  Section  3) which the Holder
would hold on the date of such  exercise  if on the date  thereof the Holder had
been the holder of record of the number of shares of Common  Stock called for on
the face of this  Warrant  and had  thereafter,  during the period from the date
thereof to and including the date of such exercise, retained such shares and all
such other or additional stock and other securities and property (including cash
in the  case  referred  to in  subdivisions  (b)  and  (c) of  this  Section  3)
receivable by the Holder as aforesaid  during such period,  giving effect to all
adjustments called for during such period by Section 4.

         4. Exercise upon Reorganization, Consolidation, Merger, etc. In case at
any time or from time to time,  the Company  shall (a) effect a  reorganization,
(b) consolidate  with or merge into any other Person,  (c) effect an exchange of
outstanding  shares of the Company  for  securities  of any other  Person or (d)
transfer  all or  substantially  all of its  properties  or  assets to any other
Person  under  any plan or  arrangement  contemplating  the  dissolution  of the
Company,  then,  in each  such  case,  as a  condition  of such  reorganization,
consolidation,  merger,  share exchange,  sale or conveyance,  the Company shall
cause  effective  provisions  to be made so that the Holder shall have the right
thereafter, by exercising this Warrant (in lieu of the shares of Common Stock of
the Company  purchasable and receivable upon exercise of the rights  represented
hereby immediately prior to such transaction) to purchase the kind and amount of
shares of stock and other  securities and property  (including  cash) receivable
upon  such  reorganization,  consolidation,  merger,  share  exchange,  sale  or
conveyance  by a holder of the number of shares of Common  Stock that might have
been  received  upon  exercise  of  this  Warrant   immediately  prior  to  such
reorganization,  consolidation,  merger,  share  exchange,  sale or  conveyance;
provided,  however, that in the event (a) the value of the stock,  securities or
other assets or property  (determined in good faith by the Board of Directors of
the  Company)  issuable or payable  with respect to one share of Common Stock of
the  Company  purchasable  and  receivable  upon  the  exercise  of  the  rights
represented  hereby  immediately  prior to such  transaction is in excess of the
Purchase   Price   hereof  in  effect  at  the  time  of  such   reorganization,
consolidation,  merger, share exchange,  sale or conveyance (after giving effect
to any  adjustment in such Purchase Price required to be made under the terms of
this  Warrant),  and  (b)  the  securities,  if  any,  to be  received  in  such
reorganization,  consolidation,  merger, share exchange,  sale or conveyance are
publicly traded,  then if the Company gives the Holder at least 20 Business Days
(or such lesser  period as the Company gives notice of such  transaction  to the
holders  of the  outstanding  shares  of  Common  Stock)  prior  notice  of such
reorganization,  merger,  share exchange,  sale or conveyance this Warrant shall
expire unless  exercised prior to such  reorganization,  consolidation,  merger,
share exchange, sale or conveyance.  Any such provision shall include provisions
for  adjustments  in respect of such  shares of stock and other  securities  and
property  that  shall  be as  nearly  equivalent  as may be  practicable  to the
adjustments  provided for in this Warrant.  The provisions of this section shall
apply to successive reorganizations,  consolidations,  mergers, share exchanges,
sales and conveyances.

         5. Adjustment for  Extraordinary  Events. In the event that the Company
shall (i) issue  additional  shares of the Common  Stock as a dividend  or other
distribution  on  outstanding  Common Stock,  (ii)  subdivide or reclassify  its
outstanding shares of Common Stock,

                                      IV-7

<PAGE>


or (iii) combine its outstanding shares of Common Stock into a smaller number of
shares of Common  Stock,  then,  in each such event,  the Purchase  Price shall,
simultaneously  with the happening of such event, be adjusted by multiplying the
Purchase  Price in effect  immediately  prior to such event by a  fraction,  the
numerator  of which  shall be the number of shares of Common  Stock  outstanding
immediately prior to such event and the denominator of which shall be the number
of shares of Common  Stock  outstanding  immediately  after such event,  and the
product so obtained shall  thereafter be the Purchase Price then in effect.  The
Purchase Price, as so adjusted,  shall be readjusted in the same manner upon the
happening of any successive  event or events described herein in this Section 5.
The Holder shall thereafter, on the exercise hereof as provided in Section 1, be
entitled  to  receive  that  number  of shares of  Common  Stock  determined  by
multiplying the number of shares of Common Stock which would be issuable on such
exercise  immediately  prior to such  issuance  by a  fraction  of which (i) the
numerator is the Purchase Price in effect immediately prior to such issuance and
(ii)  the  denominator  is the  Purchase  Price  in  effect  on the date of such
exercise.

         6.  Further  Assurances.  The Company  will take all action that may be
necessary or appropriate in order that the Company may validly and legally issue
fully paid and  nonassessable  shares of stock,  free from all taxes,  liens and
charges with respect to the issue thereof, on the exercise of all or any portion
of this Warrant from time to time outstanding.

         7. Notices of Record Date, etc. In the event of

         (a) any taking by the  Company of a record of the  holders of any class
     of securities  for the purpose of determining  the holders  thereof who are
     entitled  to  receive  any  dividend  on,  or any right to  subscribe  for,
     purchase or otherwise acquire any shares of stock of any class or any other
     securities or property, or to receive any other right, or

         (b) any capital  reorganization of the Company, any reclassification or
     recapitalization of the capital stock of the Company or any transfer of all
     or  substantially  all of the assets of the Company to or  consolidation or
     merger of the Company with or into any other Person, or

         (c) any voluntary or involuntary dissolution, liquidation or winding-up
     of the Company,

then and in each such event the  Company  will mail or cause to be mailed to the
Holder, at least ten days prior to such record date, a notice specifying (i) the
date on which any such record is to be taken for the  purpose of such  dividend,
distribution  or right,  and stating the amount and character of such  dividend,
distribution  or  right,  (ii)  the  date  on  which  any  such  reorganization,
reclassification,  recapitalization, transfer, consolidation or merger (to which
the Company is a party and for which approval of any stockholders of the Company
is required,  other than a  consolidation  or merger in which the Company is the
continuing corporation and that does not

                                      IV-8

<PAGE>


result  in any  reclassification  or change of the  Common  Stock  outstanding),
dissolution, liquidation or winding-up is to take place, and the time, if any is
to be fixed,  as of which  the  holders  of  record  of  Common  Stock (or Other
Securities) shall be entitled to exchange their shares of Common Stock (or Other
Securities) for securities or other property deliverable on such reorganization,
reclassification,    recapitalization,    transfer,    consolidation,    merger,
dissolution,  liquidation or  winding-up,  and (iii) the amount and character of
any stock or other  securities,  or  rights or  options  with  respect  thereto,
proposed to be issued or granted,  the date of such proposed  issue or grant and
the  Persons or class of Persons to whom such  proposed  issue or grant is to be
offered or made. Such notice shall also state that the action in question or the
record date is subject to the  effectiveness  of a registration  statement under
the Securities Act or a favorable vote of stockholders if either is required.

         8. Reservation of Stock,  etc.,  Issuable on Exercise of Warrants.  The
Company will at all times reserve and keep  available out of its  authorized but
unissued  shares of capital  stock,  solely for  issuance  and  delivery  on the
exercise of this  Warrant,  a  sufficient  number of shares of Common  Stock (or
Other  Securities) to effect the full exercise of this Warrant and the exercise,
conversion  or  exchange  of any  other  warrant  or  security  of  the  Company
exerciseable for, convertible into,  exchangeable for or otherwise entitling the
holder to acquire  shares of Common Stock (or Other  Securities),  and if at any
time the number of  authorized  but  unissued  shares of Common  Stock (or Other
Securities)  shall not be  sufficient  to effect such  exercise,  conversion  or
exchange, the Company shall take such action as may be necessary to increase its
authorized  but unissued  shares of Common Stock (or Other  Securities)  to such
number as shall be sufficient for such purposes.

         9. Transfer of Warrant.  This Warrant shall inure to the benefit of the
successors to and assigns of the Holder.  This Warrant and all rights hereunder,
in whole or in part,  are  registrable  at the  office or agency of the  Company
referred  to below by the Holder in Person or by his duly  authorized  attorney,
upon surrender of this Warrant properly endorsed.

         10. Register of Warrants.  The Company shall maintain, at the principal
office of the Company (or such other office as it may designate by notice to the
Holder),  a register in which the Company  shall  record the name and address of
the Person in whose name this Warrant has been  issued,  as well as the name and
address of each successor and prior owner of such Warrant.  The Company shall be
entitled to treat the Person in whose name this Warrant is so  registered as the
sole and absolute owner of this Warrant for all purposes.

         11.  Exchange  of  Warrant.  This  Warrant  is  exchangeable,  upon the
surrender  hereof by the Holder at the office or agency of the Company  referred
to in Section 10, for one or more new Warrants of like tenor representing in the
aggregate the right to subscribe for and purchase the number of shares of Common
Stock which may be  subscribed  for and  purchased  hereunder,  each of such new
Warrants to  represent  the right to subscribe  for and purchase  such number of
shares as shall be designated by the Holder at the time of such surrender.

                                      IV-9

<PAGE>


         12.  Replacement  of  Warrant.  On receipt by the  Company of  evidence
reasonably  satisfactory  to it  of  the  ownership  of  and  the  loss,  theft,
destruction or mutilation of this Warrant and (a) in the case of loss,  theft or
destruction, of indemnity from the Holder reasonably satisfactory in form to the
Company (and without the requirement to post any bond or other security), or (b)
in the case of mutilation,  upon surrender and cancellation of this Warrant, the
Company will  execute and deliver to the Holder a new Warrant of like tenor.  In
connection  with the issuance of any such new  Warrant,  the Holder shall pay or
reimburse the Company for the  reasonable  and  documented  attorneys'  fees and
expenses  incurred by the Company in connection  therewith (but not in excess of
$500.00 for each such issuance).

         13.  Warrant  Agent.  The Company may, by written notice to the Holder,
appoint the transfer  agent and  registrar for the Common Stock as the Company's
agent for the  purpose  of issuing  Common  Stock (or Other  Securities)  on the
exercise of this Warrant  pursuant to Section 1, and the Company may, by written
notice to the Holder,  appoint an agent  having an office in the United State of
America for the purpose of exchanging  this Warrant  pursuant to Section 11, and
replacing  this  Warrant  pursuant to Section 12, or any of the  foregoing,  and
thereafter any such exchange or  replacement,  as the case may be, shall be made
at such office by such agent.

         14.  Remedies.  The Company  stipulates that the remedies at law of the
Holder in the event of any default or  threatened  default by the Company in the
performance  of or compliance  with any of the terms of this Warrant are not and
will not be  adequate,  and that such terms may be  specifically  enforced  by a
decree for the specific  performance of any agreement  contained herein or by an
injunction against a violation of any of the terms hereof or otherwise.

         15. No Rights or Liabilities  as a Stockholder.  This Warrant shall not
entitle the Holder to any voting rights or other rights as a stockholder  of the
Company. Nothing contained in this Warrant shall be construed as conferring upon
Holder  hereof  the  right  to vote or to  consent  or to  receive  notice  as a
stockholder  of the  Company  on any  matters  or  with  respect  to any  rights
whatsoever as a stockholder  of the Company.  No dividends or interest  shall be
payable or accrued in respect of this Warrant or the interest represented hereby
or the Common Stock (or Other Securities)  purchasable hereunder until, and only
to the extent that,  this Warrant shall have been  exercised in accordance  with
its terms.

         16. Notices, etc. All notices and other communications from the Company
to the Holder shall be mailed by first class certified mail, postage prepaid, at
such address as may have been  furnished to the Company in writing by the Holder
or at the address  shown for the Holder on the register of Warrants  referred to
in Section 10.

         17. Transfer  Restrictions.  This Warrant has not been and is not being
registered under the provisions of the 1933 Act or any state securities laws and
this Warrant may not be  transferred  unless (1) the  transferee  is a Permitted
Transferee  and (2) the Holder shall have delivered to the Company an opinion of
counsel, reasonably satisfactory in form, scope and

                                      IV-10

<PAGE>


substance  to the  Company,  to the  effect  that  this  Warrant  may be sold or
transferred  pursuant without registration under the 1933 Act. Prior to any such
transfer,  such transferee shall have represented in writing to the Company that
such  transferee  has requested  and received  from the Company all  information
relating  to the  business,  properties,  operations,  condition  (financial  or
other),  results of  operations or prospects of the Company  deemed  relevant by
such  transferee;  that such transferee has been afforded the opportunity to ask
questions of the Company concerning the foregoing and has had the opportunity to
obtain  and  review  the  Registration  Statement  and the  prospectus  included
therein,  each as  amended  or  supplemented  to the  date of  transfer  to such
transferee,  and the reports and other information  concerning the Company which
at the  time of such  transfer  have  been  filed  by the  Company  with the SEC
pursuant to the  Exchange  Act and which are  incorporated  by reference in such
prospectus  as of the date of such  transfer.  If such  transfer  is intended to
assign the rights and  obligations  under Sections 5(a),  5(b) and 8 of the Note
Purchase  Agreement,  such transfer shall  otherwise be made in compliance  with
Section 10(j) of the Note Purchase Agreement.

         18.  Legend.  Unless  theretofore   registered  for  resale  under  the
Securities Act, each certificate for shares issued upon exercise of this Warrant
shall bear the following legend:

     The securities  represented by this  certificate  have not been  registered
     under the  Securities  Act of 1933, as amended.  The  securities  have been
     acquired for investment  and may not be resold,  transferred or assigned in
     the absence of an effective registration statement for the securities under
     the  Securities  Act of 1933,  as  amended,  or an opinion of counsel  that
     registration is not required under said Act.

         19.  Miscellaneous.  This  Warrant and any terms hereof may be changed,
waived,  discharged or terminated only by an instrument in writing signed by the
party against whom enforcement of such change, waiver,  discharge or termination
is sought.  This Warrant shall be construed and enforced in accordance  with and
governed by the internal laws of the State of  California.  The headings in this
Warrant are for  purposes of  reference  only,  and shall not limit or otherwise
affect  any of the terms  hereof.  The  invalidity  or  unenforceability  of any
provision  hereof shall in no way affect the validity or  enforceability  of any
other provision.

         20. Attorneys' Fees. In any litigation, arbitration or court proceeding
between the Company and Holder relating  hereto,  the prevailing  party shall be
entitled to attorneys'  fees and expenses and all costs of proceedings  incurred
in enforcing this Warrant.

                                      IV-11

<PAGE>


         IN WITNESS WHEREOF,  the Company has caused this Warrant to be executed
on its behalf by one of its officers thereunto duly authorized.

Dated:              , 1997                    SUGEN, INC.


                                              By:_______________________________

                                              Title:____________________________

                                      IV-1

<PAGE>


                              FORM OF SUBSCRIPTION

                                   SUGEN, INC.

                   (To be signed only on exercise of Warrant)

TO:      SUGEN, Inc.
         351 Galveston Drive
         Redwood City, California  94063-4720

         Attention:  Vice President, Finance

         1. The undersigned  Holder of the attached  original,  executed Warrant
hereby elects to exercise its purchase  right under such Warrant with respect to
______________ shares (the "Exercise Shares") of Common Stock, as defined in the
Warrant, of SUGEN, Inc., a Delaware corporation (the "Company").

         2. The undersigned Holder (check one):

o  (a)   elects to pay the  aggregate  purchase  price for such shares of Common
         Stock  (i) in lawful  money of the  United  States  or by the  enclosed
         certified or official bank check  payable in United  States  dollars to
         the order of the Company in the amount of $___________, or (ii) by wire
         transfer  of United  States  funds to the account of the Company in the
         amount  of  $____________,  which  transfer  has been  made  before  or
         simultaneously with the delivery of this Form of Subscription  pursuant
         to the instructions of the Company;

   or

o  (b)   elects to receive  shares of Common  Stock  having a value equal to the
         value of the Warrant  calculated in accordance  with Section 1.2 of the
         Warrant.

         3. Please issue a stock  certificate or certificates  representing  the
appropriate  number of shares of Common Stock in the name of the  undersigned or
in such other names as is specified below:

         Name:    _____________________________________

         Address: _____________________________________

                  _____________________________________

                                      IV-2

<PAGE>


         4. The  undersigned  Holder  hereby  represents to the Company that the
exercise of the Warrant  elected  hereby does not violate  Section 1.1(b) of the
Warrant.



Dated:____________ ___, ____                  __________________________________
                                              (Signature must conform to name of
                                              Holder as specified on the face of
                                              the Warrant)

                                              __________________________________

                                              __________________________________
                                                          (Address)

                                      IV-3




                                                                    EXHIBIT 99.1


(BW) (SUGEN) (SUGN) SUGEN,  Inc.  Announces  Private  Placement of $17.5 Million
Senior Convertible Notes

         Business Editors & Health Writers

         REDWOOD CITY,  Calif.--(BW  HealthWire)--Sept.  10,  1997--SUGEN,  Inc.
(NASDAQ:SUGN)  announced  the  private  placement  of $17.5  million  of  Senior
Convertible Notes. The notes, which will not be convertible for 90 days from the
closing  date,  can  thereafter  be converted at 100% of an average of specified
trading  prices  during the 20 trading  day period  prior to a  conversion.  The
private placement is scheduled to close on September 12.

         The convertible notes will be sold at par, mature in September 2000 and
bear interest at a rate of 5.0% per annum. Interest on the convertible notes may
be paid in SUGEN  Common  Stock or cash at the  Company's  option.  Starting  on
January  19,  1998,  the  conversion  price may not exceed  115% of the  average
closing bid price of the SUGEN Common Stock for the 20 trading days  immediately
preceding  this date.  The investors  will also be issued three year warrants to
acquire  262,500  shares of Common Stock which have an exercise price of $16.74.
If the notes are not  converted  into Common  Stock,  upon maturity in September
2000 they will be exchanged for 13.75% 5-year debentures.

         "This  innovative  financing  allows us to  maintain  the  strength  of
SUGEN's  financial  position  while  addressing  concerns about dilution and the
disruption to trading of stock that so often occur with  conventional  secondary
offerings,"  stated Stephen  Evans-Freke,  SUGEN's  Chairman and Chief Executive
Officer.  "The  structure of this  financing  allows us to tap into new pools of
capital  not   traditionally   available  to   biotechnology   companies.   More
importantly,  the absence of a  discount-to-market  in the conversion pricing is
crucial in aligning the interests of the noteholder with the Company.  Moreover,
the  financing  was  effected  with a very small and select  group of  investors
assembled and led by Diaz & Altschul Capital LLC."

         Diaz & Altschul  Capital,  LLC of New York City was the placement agent
in the  transaction.  Delta  Opportunity  Fund, Ltd., which is advised by Diaz &
Altschul  Advisors,  LLC,  is the lead  investor in the  transaction.  SUGEN has
agreed to file a  registration  statement  for the resale of the shares of SUGEN
Common Stock acquired on conversion of the convertible notes and exercise of the
warrants within 30 days of the closing date.

         SUGEN, Inc. is a biopharamceutical  company focusing on the development
of new classes of small molecule drugs which interact in a specific  manner with
different members of the tyrosine kinase,  serine-threonine  kinase and tyrosine
phosphatase  families of signal  transduction  molecules,  and their  signalling
pathways.  These pathways are involved in a number of human  diseases  including
cancer and diabetes, as well as disorders of the body's



<PAGE>


immune  defenses and  neurological  systems.  SUGEN  currently has SU101 (a PDGF
receptor  inhibitor) in Phase II clinical studies for the treatment of malignant
gliomas  and  other  cancers;  SU5271  (an EGF  receptor  inhibitor)  in Phase I
clinical studies for the treatment of psoriasis; and recently filed an IND for a
Flk-1  angiogenesis   inhibitor.   The  Company  has  research  and  development
collaborations with Zeneca, ASTA Medica and Allergan.

         This press release  contains,  in addition to  historical  information,
forward-looking  statements that involve risks and uncertainties.  The Company's
actual  results  could differ  significantly  from the results  discussed in the
forward-looking  statements.  Factors  that could  cause or  contribute  to such
differences  include the factors more fully discussed in the Company's 1996 Form
10-K and most recent Form 10-Q. The Company  undertakes no obligation to release
the results of any  revision to these  forward-looking  statements  which may be
made to reflect events or  circumstances  occurring  after the date hereof or to
reflect the occurrence of unanticipated events.

         Additional  written  materials and press releases  regarding  SUGEN are
available  through  the  SUGEN  Fax-On-Demand  Information  Service  by  dialing
888/329-4699.


         Contact: SUGEN, Inc.
                  D. Kevin Kwok, 650/306-7700
                  [email protected]
                           or
                  Burns McClellan, Inc.
                  Reagan Codner, 212/213-0006 (investors)
                  Audra Nass, 415/352-6262 (media)




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