EXHIBIT 10.1

                               PURCHASE AGREEMENT

            THIS AGREEMENT is made as of the 30th day of January, 2001, by and
between Triangle Pharmaceuticals, Inc. (the "Company"), a corporation organized
under the laws of the State of Delaware, with its principal offices at 4
University Place, 4611 University Drive, Durham, North Carolina 27707, and the
purchaser whose name and address is set forth on the signature page hereof (the
"Purchaser").

            IN CONSIDERATION of the mutual covenants contained in this
Agreement, the Company and the Purchaser agree as follows:

            SECTION 1. Authorization of Sale of the Shares. Subject to the terms
and conditions of this Agreement, the Company has authorized the sale of up to
230,000 shares (the "Shares") of the Series B Preferred Stock, par value $0.001
per share (the "Preferred Stock"), of the Company. Subject to adjustments
pursuant to the terms of the Certificate of Designations, Preferences and Rights
of the Preferred Stock (the "Certificate"), substantially in the form attached
hereto as Exhibit A, to be filed by the Company with the Secretary of State of
the State of Delaware on or prior to the Closing Date (as defined in Section 3),
each share of Preferred Stock shall be convertible into 10 shares (the
"Underlying Shares") of common stock, par value $0.001 per share, of the Company
(the "Common Stock") and shall possess such other rights and preferences as are
set forth in the Certificate.

            SECTION 2. Agreement to Sell and Purchase the Shares. At the Closing
(as defined in Section 3), the Company will sell to the Purchaser, and the
Purchaser will buy from the Company, upon the terms and conditions hereinafter
set forth, the number of Shares (at the purchase price) shown below:

                              Price Per
       Number to Be            Share In             Aggregate
        Purchased              Dollars                Price
        ---------              -------                -----

                               $60.00

            The Company proposes to enter into this same form of purchase
agreement with certain other investors (the "Other Purchasers") and expects to
complete sales of the Shares to them. The Purchaser and the Other Purchasers are
hereinafter sometimes collectively referred to as the "Purchasers," and this
Agreement and the agreements executed by the Other Purchasers are hereinafter
sometimes collectively referred to as the "Agreements." The term "Placement
Agent" shall mean Banc of America Securities LLC.

            SECTION 3. Delivery of the Shares at the Closing. The completion of
the purchase and sale of the Shares (the "Closing") shall occur as soon as
practicable and as agreed by the parties hereto following receipt of evidence
satisfactory to the Company and the Purchaser that the Certificate has been
filed with and accepted by the Secretary of State of the State of Delaware, at a
place and time (the "Closing Date") to be agreed upon by the Company and the
Placement Agent and of which the Purchasers will be notified by facsimile
transmission or otherwise.

            At the Closing, the Company shall deliver to the Purchaser one or
more stock certificates registered in the name of the Purchaser, or in such
nominee name(s) as designated by the Purchaser in writing, representing the
number of Shares set forth in Section 2 above. The name(s) in which the stock
certificates are to be registered are set forth in the Stock Certificate
Questionnaire attached hereto as part of Appendix I. The Company's obligation to
complete the purchase and sale of the Shares and deliver such stock
certificate(s) to the Purchaser at the Closing shall be subject to the following
conditions, any one or more of which may be waived by the Company: (a) Nasdaq
approval of the transaction; (b) receipt by the Company of same-day funds in the
full amount of the purchase price for the Shares being purchased hereunder; (c)
completion of the purchases and sales under the



Agreements with all of the Other Purchasers; (d) the accuracy of the
representations and warranties made by the Purchasers and the fulfillment of
those undertakings of the Purchasers to be fulfilled prior to the Closing; and
(e) receipt of evidence satisfactory to it that the Certificate has been filed
with and accepted by the Secretary of State of the State of Delaware. The
Purchaser's obligation to accept delivery of such stock certificate(s) and to
pay for the Shares evidenced thereby shall be subject to the following
conditions: (a) the accuracy in all material respects of the representations and
warranties made by the Company herein and the fulfillment in all material
respects of those undertakings of the Company to be fulfilled prior to Closing;
and (b) receipt of evidence satisfactory to it that the Certificate has been
filed with and accepted by the Secretary of State of the State of Delaware. The
Purchaser's obligations hereunder are expressly not conditioned on the purchase
by any or all of the Other Purchasers of the Shares that they have agreed to
purchase from the Company.

            SECTION 4. Representations, Warranties and Covenants of the Company.
The Company hereby represents and warrants to, and covenants with, the Purchaser
as follows:

            4.1. Organization and Qualification. The Company is a corporation
duly organized, validly existing and in good standing under the laws of its
jurisdiction of incorporation, and the Company is qualified to do business as a
foreign corporation in each jurisdiction in which qualification is required,
except where failure to so qualify would not have a Material Adverse Effect (as
defined herein). The Company has only one subsidiary (the "Subsidiary"), which
is a wholly-owned subsidiary of the Company and which has no material assets,
other than those assets described in the Company's 10-K for the year ended
December 31, 1999 (Exhibit A). The Subsidiary is duly organized, validly
existing and in good standing under the laws of its jurisdiction of
incorporation and is qualified to do business as a foreign corporation in each
jurisdiction in which qualification is required, except where failure to so
qualify would not have a Material Adverse Effect.

            4.2. Authorized Capital Stock. Except as disclosed in or
contemplated by the Confidential Private Placement Memorandum dated January 19,
2001 prepared by the Company, including all Exhibits (except Exhibit G),
supplements and amendments thereto (the "Private Placement Memorandum"), the
Company had authorized and outstanding capital stock as set forth under the
heading "Capitalization" in the Private Placement Memorandum as of the date set
forth therein; the issued and outstanding shares of the Company's Common Stock
have been duly authorized and validly issued, are fully paid and nonassessable,
have been issued in compliance with all federal and state securities laws, were
not issued in violation of or subject to any preemptive rights or other rights
to subscribe for or purchase securities, and conform in all material respects to
the description thereof contained in the Private Placement Memorandum. Except as
disclosed in or contemplated by the Private Placement Memorandum (including the
issuance of options under the Company's 1996 Stock Incentive Plan and the
issuance of shares of Common Stock pursuant to the Company's Employee Stock
Purchase Plan after September 30, 1998), and the 7,700,000 shares of Common
Stock the Company has agreed to issue and sell pursuant to Purchase Agreements
dated January 30, 2001, the Company does not have outstanding any options to
purchase, or any preemptive rights or other rights to subscribe for or to
purchase, any securities or obligations convertible into, or any contracts or
commitments to issue or sell, shares of its capital stock, any shares of capital
stock of any subsidiary or any such options, rights, convertible securities or
obligations. The description of the Company's stock, stock bonus and other stock
plans or arrangements and the options or other rights granted and exercised
thereunder, set forth in the Private Placement Memorandum accurately and fairly
presents the information required to be shown with respect to such plans,
arrangements, options and rights.

            4.3. Issuance, Sale and Delivery of the Shares. The Shares have been
duly authorized and, when issued, delivered and paid for in the manner set forth
in this Agreement, will be duly authorized, validly issued, fully paid and
nonassessable, and will be entitled to the rights and benefits described in the
Certificate. No preemptive rights or other rights to subscribe for or purchase
exist with respect to the issuance and sale of the Shares by the Company
pursuant to these Agreements or as a result of the issuance of the Underlying
Shares upon the conversion of the Shares. No stockholder of the Company has any
right (which has not been waived or has not expired by reason of lapse of time
following notification of the Company's intent to file a registration statement
on behalf of the Purchasers pursuant to Section 7.1 hereof (the "Registration
Statement")) to require the Company to register the sale of any securities owned
by such stockholder under the Securities Act of 1933, as amended (the
"Securities Act"), in the Registration Statement. No further approval or
authority of the stockholders or the Board of Directors of the


                                      -2-


Company will be required, other than as may be required by Rule
4460(i)(1)(D)(ii) of the Nasdaq National Market Issuer Designation Requirements
("Rule 4460"), for the issuance and sale of the Shares to be sold by the Company
as contemplated herein. The Underlying Shares of Common Stock have been duly
reserved for issuance upon the conversion of the Shares and the Underlying
Shares, when issued and delivered in accordance with the terms of the
Certificate, will be duly and validly issued, fully paid and nonassessable.

            4.4. Due Execution, Delivery and Performance of the Agreements. The
Company has full legal right, corporate power and authority to enter into the
Agreements and perform the transactions contemplated hereby. The Agreements have
been duly authorized, executed and delivered by the Company. The making and
performance of the Agreements by the Company and the consummation of the
transactions herein contemplated will not violate any provision of the
organizational documents of the Company or the Subsidiary and will not result in
the creation of any lien, charge, security interest or encumbrance upon any
assets of the Company or the Subsidiary pursuant to the terms or provisions of,
or will not conflict with, result in the breach or violation of, or constitute,
either by itself or upon notice or the passage of time or both, a default under
any agreement, mortgage, deed of trust, lease, franchise, license, indenture,
permit or other instrument to which the Company or the Subsidiary is a party or
by which the Company or the Subsidiary or their respective properties may be
bound or affected and in each case which would have a material adverse effect on
the condition (financial or otherwise), properties, business, prospects or
results of operations of the Company and the Subsidiary taken as a whole (a
"Material Adverse Effect") or, to the Company's knowledge, any statute or any
authorization, judgment, decree, order, rule or regulation of any court or any
regulatory body, administrative agency or other governmental body applicable to
the Company or the Subsidiary or any of its respective properties. No consent,
approval, authorization or other order of any court, regulatory body,
administrative agency or other governmental body is required for the execution
and delivery of this Agreement or the consummation of the transactions
contemplated by this Agreement, except for compliance with the Blue Sky laws and
federal securities laws applicable to the offering of the Shares and the filing
of the Certificate with the Secretary of State of the State of Delaware. Upon
their execution and delivery, and assuming the valid execution thereof by the
respective Purchasers, the Agreements will constitute valid and binding
obligations of the Company, enforceable in accordance with their respective
terms, except as enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting creditors' and
contracting parties' rights generally and except as enforceability may be
subject to general principles of equity (regardless of whether such
enforceability is considered in a proceeding in equity or at law) and except as
the indemnification agreements of the Company in Section 7.3 hereof may be
legally unenforceable.

            4.5. Accountants. PricewaterhouseCoopers LLP, who has expressed its
opinion with respect to the consolidated financial statements in the Company's
Annual Report on Form 10-K for the year ended December 31, 1999, are independent
accountants as required by the Securities Act and the rules and regulations
promulgated thereunder (the "Rules and Regulations").

            4.6. No Defaults. Except as disclosed in the Private Placement
Memorandum, and except as to defaults, violations and breaches which
individually or in the aggregate would not be material to the Company or the
Subsidiary taken as a whole, neither the Company nor the Subsidiary is in
violation or default of any provision of its certificate of incorporation or
bylaws, or other organizational documents, or in breach of or default with
respect to any provision of any agreement, judgment, decree, order, mortgage,
deed of trust, lease, franchise, license, indenture, permit or other instrument
to which it is a party or by which it or any of its properties are bound; and
there does not exist any state of fact which, with notice or lapse of time or
both, would constitute an event of default on the part of the Company or the
Subsidiary as defined in such documents, except such defaults which individually
or in the aggregate would not be material to the Company and the Subsidiary
taken as a whole.

            4.7. Contracts. The contracts described in the Private Placement
Memorandum that are material to the Company and the Subsidiary taken as a whole,
are in full force and effect on the date hereof; and neither the Company nor the
Subsidiary is, nor to the Company's knowledge is any other party, in breach of
or default under any of such contracts which would have a Material Adverse
Effect.

            4.8. No Actions. Except as disclosed in the Private Placement
Memorandum, there are no legal or governmental actions, suits or proceedings
pending or, to the Company's knowledge, threatened to which the


                                      -3-


Company or the Subsidiary is or may be a part or of which property owned or
leased by the Company or the Subsidiary is or may be the subject, or related to
environmental or discrimination matters, which actions, suits or proceedings,
individually or in the aggregate, might prevent or might reasonably be expected
to materially and adversely affect the transactions contemplated by this
Agreement or result in a material adverse change in the condition (financial or
otherwise), properties, business, prospects or results of operations of the
Company and the Subsidiary, taken as a whole (a "Material Adverse Change"); and
no labor disturbance by the employees of the Company or any of its Subsidiaries
exists, to the Company's knowledge, or is imminent which might reasonably be
expected to have a Material Adverse Effect. Except as disclosed in the Private
Placement Memorandum, neither the Company nor the Subsidiary is a party to or
subject to the provisions of any material injunction, judgment, decree or order
of any court, regulatory body administrative agency or other governmental body.

            4.9. Properties. Each of the Company and the Subsidiary has good and
marketable title to all the properties and assets reflected as owned by it in
the consolidated financial statements included in the Private Placement
Memorandum, subject to no lien, mortgage, pledge, charge or encumbrance of any
kind except (i) those, if any, reflected in such consolidated financial
statements, or (ii) those which are not material in amount and do not adversely
affect the use made and promised to be made of such property by the Company or
the Subsidiary. Each of the Company and the Subsidiary holds its leased
properties under valid and binding leases, with such exceptions as are not
materially significant in relation to their respective businesses. Except as
disclosed in the Private Placement Memorandum, each of the Company and the
Subsidiary owns or leases all such properties as are necessary to its operations
as now conducted.

            4.10. No Material Change. Since September 30, 2000 and except as
described in or specifically contemplated by the Private Placement Memorandum,
(i) the Company and the Subsidiary have not incurred any material liabilities or
obligations, indirect, or contingent, or entered into any material verbal or
written agreement or other transaction which is not in the ordinary course of
business or which could reasonably be expected to result in a material reduction
in the future earnings of the Company; (ii) the Company and the Subsidiary have
not sustained any material loss or interference with their businesses or
properties from fire, flood, windstorm, accident or other calamity not covered
by insurance; (iii) the Company and the Subsidiary have not paid or declared any
dividends or other distributions with respect to their capital stock and none of
the Company and the Subsidiary is in default in the payment of principal or
interest on any outstanding debt obligations; (iv) there has not been any change
in the capital stock of the Company or the Subsidiary other than (a) the sale of
the Shares hereunder and shares or options issued pursuant to employee equity
incentive plans or purchase plans approved by the Company's Board of Directors
and (b) the Company's agreement to issue and sell up to 7,700,000 shares of
Common Stock pursuant to the Purchase Agreements dated January 30, 2001, there
has not been any increase in or indebtedness material to the Company or the
Subsidiary (other than in the ordinary course of business); and (v) except for
the operating losses and negative cash flow the Company has continued to incur,
there has not been a Material Adverse Change.

            4.11. Intellectual Property. Except as disclosed in or specifically
contemplated by the Private Placement Memorandum, (i) the Company and the
Subsidiary own or have obtained valid and enforceable licenses or options for
the inventions, patent applications, patents, trademarks (both registered and
unregistered), tradenames, copyrights and trade secrets necessary for the
conduct of the Company's and the Subsidiary's respective businesses as currently
conducted and as the Private Placement Memorandum indicates the Company and the
Subsidiary contemplate conducting (collectively, the "Intellectual Property");
and (ii) to the Company's knowledge (for each of the following subsections (a)
through (e)): (a) there are no third parties who have any ownership rights to
any Intellectual Property that is owned by, or has been licensed to, the Company
or the Subsidiary for the product indications described in the Private Placement
Memorandum that would preclude the Company or the Subsidiary from conducting
their respective businesses as currently conducted and as the Private Placement
Memorandum indicates the Company and the Subsidiary contemplate conducting,
except for the ownership rights of the owners of the Intellectual Property
licensed or optioned by the Company or the Subsidiary; (b) there are currently
no sales of any products that would constitute an infringement by third parties
of any Intellectual Property owned, licensed or optioned by the Company or the
Subsidiary; (c) there is no pending or threatened action, suit, proceeding or
claim by others challenging the rights of the Company or the Subsidiary in or to
any Intellectual Property owned, licensed or optioned by the Company or the
Subsidiary, other than non-material claims; (d) there is no pending or
threatened action, suit, proceeding or claim by others challenging the validity
or scope of any Intellectual Property owned,


                                      -4-


licensed or optioned by the Company, other than non-material claims; and (e)
there is no pending or threatened action, suit, proceeding or claim by others
that the Company or its Subsidiary infringes or otherwise violates any patent,
trademark, copyright, trade secret or other proprietary right of others, other
than non-material claims.

            4.12. Compliance. Neither the Company nor the Subsidiary has been
advised, nor do they have any reason to believe, that they are not conducting
business in compliance with all applicable laws, rules and regulations of the
jurisdictions in which they are conducting their business, including, without
limitation, all applicable local, state and federal environmental laws and
regulations; except where failure to be so in compliance would not have a
Material Adverse Effect.

            4.13. Taxes. Each of the Company and the Subsidiary has filed all
necessary federal, state and foreign income and franchise tax returns and has
paid or accrued all taxes shown as due thereon, and each of the Company and the
Subsidiary has no knowledge of a tax deficiency which has been or might be
asserted or threatened against it which could have a Material Adverse Effect.

            4.14. Transfer Taxes. On the Closing Date, all stock transfer or
other taxes (other than income taxes) which are required to be paid in
connection with the sale and transfer of the Shares to be sold to the Purchaser
hereunder will be, or will have been, fully paid or provided for by the Company
and all laws imposing such taxes will be or will have been fully complied with.

            4.15. Investment Company. The Company is not an "investment company"
or an "affiliated person" of, or "promoter" or "principal underwriter" for an
investment company, within the meaning of the Investment Company Act of 1940, as
amended.

            4.16. Offering Materials. The Company has not distributed and will
not distribute prior to the Closing Date any offering material in connection
with the offering and sale of the Shares other than the Private Placement
Memorandum or any amendment or supplement thereto. The Company has not in the
past nor will it hereafter take any action independent of the Placement Agent to
sell, offer for sale or solicit offers to buy any securities of the Company
which would bring the offer, issuance or sale of the Shares, as contemplated by
this Agreement, within the provisions of Section 5 of the Securities Act, unless
such offer, issuance or sale was or shall be within the exemptions of Section 4
of the Securities Act.

            4.17. Insurance. Each of the Company and the Subsidiary maintains
insurance of the types and in the amounts that the Company reasonably believes
is adequate for its business, including, but not limited to, insurance covering
all real and personal property owned or leased by the Company or the Subsidiary
against theft, damage, destruction, acts of vandalism and all other risks
customarily insured against by similarly situated companies, all of which
insurance is in full force and effect.

            4.18. Contributions. Neither the Company at any time since its
incorporation nor the Subsidiary at any time since it was acquired by the
Company has, directly or indirectly, (i) made any unlawful contribution to any
candidate for public office, or failed to disclose fully any contribution in
violation of law, or (ii) made any payment to any federal or state governmental
officer or official, or other person charged with similar public or quasi-public
duties, other than payments required or permitted by the laws of the United
States or any jurisdiction thereof.

            4.19 Additional Information. The information contained in the
following documents, which the Placement Agent has furnished to the Purchaser,
or will furnish prior to the Closing, is or will be true and correct in all
material respects as of their respective final dates:

            (a) the Company's Annual Report on Form 10-K for the fiscal year
      ended December 31, 1999 (without exhibits);

            (b) the Company's Proxy Statement for the 2000 Annual Meeting of
      Stockholders;


                                      -5-


            (c) the Company's Quarterly Reports on Form 10-Q for the fiscal
      quarters ended March 31, 2000, June 30, 2000 and September 30, 2000 (each
      without exhibits);

            (d) the Company's Current Report on Form 8-K filed with the
      Commission on November 3, 2000 (without exhibits);

            (e) the Registration Statement;

            (f) the Private Placement Memorandum, including all addenda and
      exhibits thereto (other than the Appendices); and

            (g) all other documents, if any, filed by the Company with the
      Securities and Exchange Commission since September 30, 2000 pursuant to
      the reporting requirements of the Securities Exchange Act of 1934, as
      amended (the "Exchange Act").

            4.20. Legal Opinion. Prior to the Closing, Brobeck, Phleger &
Harrison LLP, counsel to the Company, will deliver its legal opinion to the
Placement Agent reasonably satisfactory to the Placement Agent and counsel to
the Placement Agent. Such opinion shall also state that each of the Purchasers
may rely thereon as though it were addressed directly to such Purchaser.

            4.21. Intellectual Property Opinion. Prior to the Closing, King &
Spalding, patent counsel for the Company, will deliver its legal opinion to the
Placement Agent reasonably satisfactory to the Placement Agent and counsel to
the Placement Agent. Such opinion shall state that each of the Purchasers may
rely thereon as though it were addressed directly to such Purchaser.

            4.22. No Integration. Neither the Company nor any of its affiliates
nor any person acting on the Company's behalf has, directly or indirectly, at
any time within the past six (6) months made, nor will any such party make
within six (6) months of the Closing Date, any offer or sale of any security or
solicitation of any offer to buy any security under circumstances, that in the
opinion of the Company's counsel, concurred by the Placement Agent's counsel,
would eliminate the availability of the exemption from registration under
Regulation D under the Securities Act in connection with the offer and sale of
the Securities as contemplated hereby.

            4.23. Certificate. At the Closing, the Company will deliver to
Purchaser a certificate executed by the Chairman of the Board or President and
the chief financial or accounting officer of the Company, dated the Closing
Date, in form and substance reasonably satisfactory to the Purchasers, to the
effect that the representations and warranties of the Company set forth in this
Section 4 are true and correct in all material respects as of the date of this
Agreement and as of the Closing Date, and the Company has complied with all the
agreements and satisfied all the conditions herein on its part to be performed
or satisfied on or prior to such Closing Date.

            4.24. Stockholder Approval. The Company covenants and agrees that if
stockholder approval is required pursuant to Rule 4460, it will (i) include in
its proxy statement for its 2001 Annual Meeting of Stockholders a proposal
seeking stockholder approval of the terms of the issuance and sale of the Shares
pursuant to the Agreements and (ii) note in the proposal that the Company's
Board of Directors recommends that stockholders approve the terms of the
issuance and sale of the Shares pursuant to the Agreements.

            SECTION 5. Representations, Warranties and Covenants of the
Purchaser. (a) The Purchaser represents and warrants to, and covenants with, the
Company that: (i) the Purchaser is knowledgeable, sophisticated and experienced
in making, and is qualified to make, decisions with respect to investments in
shares representing an investment decision like that involved in the purchase of
the Shares, including investments in securities issued by the Company, and has
requested, received, reviewed and considered all information it deems relevant
in making an informed decision to purchase the Shares; (ii) the Purchaser is
acquiring the number of Shares set forth in Section 2 above in the ordinary
course of its business and for its own account for investment only and with no
present intention of distributing any of such Shares (or the Underlying Shares)
or any arrangement or understanding with any other persons regarding the
distribution of such Shares (or the Underlying Shares); (iii) the Purchaser will
not,


                                      -6-


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 Shares or Underlying Shares except in compliance with the
Securities Act and the Rules and Regulations; (iv) the Purchaser has completed
or caused to be completed the Stock Certificate Questionnaire, attached hereto
as Appendix I, and the answers thereto are true and correct as of the date
hereof; (v) the Purchaser will complete and deliver, or cause to be completed
and delivered, to the Company within 10 days after the date the Shares are
converted into Underlying Shares, the Registration Statement Questionnaire,
attached hereto as Appendix I, for use in preparation of the Registration
Statement, and the answers thereto will be true and correct as of the date the
Questionnaire is delivered to the Company and as of the effective date of the
Registration Statement; (vi) the Purchaser has, in connection with its decision
to purchase the number of Shares set forth in Section 2 above, (a) relied solely
upon the Private Placement Memorandum and the representations and warranties of
the Company contained herein and (b) had a reasonable opportunity to ask
questions of, and receive answers from, the Company concerning the Company and
the offering of the Shares; (vii) the Purchaser acknowledges that the price and
terms of the Preferred Stock offered hereby have been determined by negotiation
based in part on the market price for the Common Stock, and that it does not
necessarily bear any relationship to the assets, book value or potential
performance of the Company or any other recognized criteria of value; and (viii)
the Purchaser is either a "large institutional accredited investor" as defined
in Rule 501(a)(1), (2), (3), (7) and (8) under the Securities Act and within the
meaning of the SEC No-Action Letters: Black Box, Inc. (June 26, 1990) and
Squadron, Elenoff, Pleasant & Lehrer (February 28, 1992), or is a "qualified
institutional buyer" as such term is defined in Rule 144A(a)(1) under the
Securities Act.

            (b) The Purchaser hereby covenants with the Company not to (1) make
      any sale of the Shares except in compliance with the Securities Act and
      the Rules and Regulations, and the Purchaser acknowledges and agrees that
      the Shares are not transferable on the books of the Company unless the
      certificate submitted to the transfer agent evidencing the Shares is
      accompanied by an opinion of counsel, satisfactory in form and substance
      to the Company, to the effect that the Shares have been sold in compliance
      with the Securities Act and the Rules and Regulations and any applicable
      state securities laws or Blue Sky laws, and (2) make any sale of the
      Underlying Shares without satisfying the prospectus delivery requirement
      under the Securities Act, and the Purchaser acknowledges and agrees that
      the Underlying Shares are not transferable on the books of the Company
      unless the certificate submitted to the transfer agent evidencing the
      Underlying Shares is accompanied by a separate officer's certificate: (i)
      in the form of Appendix II hereto, (ii) executed by an officer of, or
      other authorized person designated by, the Purchaser and (iii) to the
      effect that (A) the Underlying Shares have been sold in accordance with
      the Registration Statement, the Securities Act and the Rules and
      Regulations and any applicable state securities or Blue Sky laws and (B)
      the requirement of delivering a current prospectus has been satisfied. The
      Purchaser acknowledges that there may occasionally be times when the
      Company must suspend the use of the prospectus forming a part of the
      Registration Statement until such time as an amendment to the Registration
      Statement has been filed by the Company and declared effective by the
      Commission, or until such time as the Company has filed an appropriate
      report with the Commission pursuant to the Exchange Act; provided,
      however, that such suspensions may only be made by the Company pursuant to
      the terms of the last paragraph of Section 7.1 of this Agreement. The
      Purchaser hereby covenants that it will not sell any Underlying Shares
      pursuant to said prospectus during the period commencing at the time at
      which the Company gives the Purchaser written notice of the suspension of
      the use of said prospectus and ending at the time the Company gives the
      Purchaser written notice that the Purchaser may thereafter effect sales
      pursuant to said prospectus. The Company hereby covenants that it will
      promptly notify the Purchaser of the commencement and ending of such
      period. The Purchaser further covenants to notify the Company promptly of
      the sale of all of its Underlying Shares.

            (c) The Purchaser understands that the Shares are being offered and
      sold to it in reliance upon specific exemptions from the registration
      requirements of the Securities Act, the Rules and Regulations and state
      securities laws and that the Company is relying upon the truth and
      accuracy of, and the Purchaser's compliance with, the representations,
      warranties, agreements, acknowledgments and understandings of the
      Purchaser set forth herein in order to determine the availability of such
      exemptions and the eligibility of the Purchaser to acquire the Shares.


                                      -7-


            (d) The Purchaser understands that the information contained in the
      Private Placement Memorandum is strictly confidential and proprietary to
      the Company and has been prepared from the Company's publicly available
      documents and other information and is being submitted to the Purchaser
      solely for such Purchaser's confidential use. The Purchaser agrees to use
      the information contained in the Private Placement Memorandum for the sole
      purpose of evaluating a possible investment in the Shares and the
      Purchaser hereby acknowledges that it is prohibited from reproducing or
      distributing the Private Placement Memorandum, this Purchase Agreement, or
      any other offering materials, in whole or in part, or divulging or
      discussing any of their contents. Further, the Purchaser understands and
      expressly agrees that the existence and nature of all conversations and
      presentations, if any, regarding the Company and this offering, as well as
      any other information about the Company received by the Purchaser in
      connection with this Offering must be kept strictly confidential. The
      Purchaser understands that the federal securities laws impose restrictions
      on trading based on information regarding this offering. In addition, the
      Purchaser hereby acknowledges that unauthorized disclosure of information
      regarding this offering may cause the Company to violate Regulation FD.

            (e) The Purchaser understands that its investment in the Shares
      involves a significant degree of risk and that the market price of the
      Common Stock has been volatile and that no representation is being made as
      to the future value of the Common Stock. The Purchaser has the knowledge
      and experience in financial and business matters as to be capable of
      evaluating the merits and risks of an investment in the Shares and has the
      ability to bear the economic risks of an investment in the Shares.

            (f) The Purchaser understands that no United States federal or state
      agency or any other government or governmental agency has passed upon or
      made any recommendation or endorsement of the Shares.

            (g) The Purchaser understands that, until such time as the shares
      may be sold pursuant to Rule 144 under the Securities Act without any
      restriction as to the number of securities as of a particular date that
      can then be immediately sold, the Shares (or the Underlying Shares, as
      applicable) 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 may not be sold, transferred or assigned in the absence
            of an effective registration statement for the securities under said
            Act, or an opinion of counsel, in form, substance and scope
            reasonably acceptable to the Company, that registration is not
            required under said Act or unless sold pursuant to Rule 144 under
            said Act."

            (h) The Purchaser's principal executive offices are in the
      jurisdiction set forth immediately below the Purchaser's name on the
      signature pages hereto.

            (i) The Purchaser further represents and warrants to, and covenants
      with, the Company that (i) the Purchaser has full right, power, authority
      and capacity to enter into this Agreement and to consummate the
      transactions contemplated hereby and has taken all necessary action to
      authorize the execution, delivery and performance of this Agreement, and
      (ii) upon the execution and delivery of this Agreement, this Agreement
      shall constitute a legal, valid and binding obligation of the Purchaser,
      enforceable in accordance with its terms, except as enforceability may be
      limited by applicable bankruptcy, insolvency, reorganization, moratorium
      or similar laws affecting creditors' and contracting parties' rights
      generally and except as enforceability may be subject to general
      principles of equity (regardless of whether such enforceability is
      considered in a proceeding in equity or at law) and except as the
      indemnification agreements of the Purchaser in Section 7.3 hereof may be
      legally unenforceable.


                                      -8-


            (j) The Purchaser hereby represents that if the Purchaser is not a
      United States person (as such term is defined under Regulation S of the
      Securities Act), the Purchaser has satisfied itself as to the full
      observance of the laws of its jurisdiction in connection with any
      invitation to subscribe for the Shares or any use of this Agreement,
      including (i) the legal requirements within its jurisdiction for the
      purchase of the Shares, (ii) any foreign exchange restrictions applicable
      to such purchase, (iii) any governmental or other consents that may need
      to be obtained and (iv) the income tax and other tax consequences, if any,
      that may be relevant to the purchase, holding, redemption, sale or
      transfer of the Shares. The Purchaser further represents that its
      subscription and payment for, and its continued beneficial ownership of
      the Shares, will not violate any applicable securities or other laws of
      its jurisdiction.

            SECTION 6. Survival of Representations, Warranties and Agreements.
Notwithstanding any investigation made by any party to this Agreement or by the
Placement Agent, all covenants, agreements, representations and warranties made
by the Company and the Purchaser herein and in the certificates for the Shares
delivered pursuant hereto shall survive the execution of this Agreement, the
delivery to the Purchaser of the Shares being purchased and the payment
therefor.

            SECTION 7. Registration of the Shares; Compliance with the
Securities Act.

            7.1. Registration Procedures and Expenses. The Company shall,
following the conversion of the Shares into Common Stock, which shall occur upon
the earlier of either (i) receipt of approval by the Company's stockholders of
the terms of the issuance and sale of the Shares, upon such approval the Shares
shall be converted into shares of Common Stock or (ii) the one-year anniversary
of the Closing Date, upon which the Shares shall automatically be converted into
shares of Common Stock (the earlier to occur of such dates, the "Conversion
Date"):

            (a)   as soon as practicable, but in no event later than 30 days
                  following the receipt by the Company of all of the Purchasers'
                  Registration Statement Questionnaires, file with the
                  Commission the Registration Statement on Form S-3 relating to
                  the sale of the Underlying Shares by the Purchaser from time
                  to time on the Nasdaq National Market or the facilities of any
                  national securities exchange on which the Common Stock is then
                  traded or in privately-negotiated transactions;

            (b)   use its reasonable efforts, subject to receipt of necessary
                  information from the Purchasers, to cause the Commission to
                  notify the Company of the Commission's willingness to declare
                  the Registration Statement effective within 75 days after the
                  Registration Statement is filed by the Company;

            (c)   prepare and file with the Commission such amendments and
                  supplements to the Registration Statement and the prospectus
                  used in connection therewith as may be necessary to keep the
                  Registration Statement effective until the earlier of (i) two
                  years after the effective date of the Registration Statement
                  or (ii) the date on which the Underlying Shares may be resold
                  by the Purchasers without registration by reason of Rule
                  144(k) under the Securities Act or any other rule of similar
                  effect;

            (d)   furnish to the Purchaser with respect to the Underlying Shares
                  registered under the Registration Statement (and to each
                  underwriter, if any, of such Underlying Shares) such
                  reasonable number of copies of prospectuses and such other
                  documents as the Purchaser may reasonably request, in order to
                  facilitate the public sale or other disposition of all or any
                  of the Underlying Shares by the Purchaser; provided, however,
                  that the obligation of the Company to deliver copies of
                  prospectuses to the Purchaser shall be subject to the receipt
                  by the Company of reasonable assurances from the Purchaser
                  that the Purchaser will comply with the applicable provisions
                  of the Securities Act and of such other securities or blue sky
                  laws as may be applicable in connection with any use of such
                  prospectuses;


                                      -9-


            (e)   file documents required of the Company for normal Blue Sky
                  clearance in states specified in writing by the Purchaser;
                  provided, however, that the Company shall not be required to
                  qualify to do business or consent to service of process in any
                  jurisdiction in which it is not now so qualified or has not so
                  consented; and

            (f)   bear all expenses in connection with the procedures in
                  paragraphs (a) through (e) of this Section 7.1 and the
                  registration of the Underlying Shares pursuant to the
                  Registration Statement, other than fees and expenses, if any,
                  of counsel or other advisers to the Purchaser or the Other
                  Purchasers or underwriting discounts, brokerage fees and
                  commissions incurred by the Purchaser or the Other Purchasers,
                  if any.

            Notwithstanding any other provision of this Agreement, the Company
      hereby agrees that it may only suspend the use of any prospectus as
      described in Section 5(b) of this Agreement three times during any 365-day
      period and that the total number of days for any individual suspension
      shall not exceed 60.

                  7.2. Transfer of Underlying Shares After Registration. The
Purchaser agrees that it will not effect any disposition of the Underlying
Shares or its right to purchase the Underlying Shares that would constitute a
sale within the meaning of the Securities Act, except as contemplated in the
Registration Statement referred to in Section 7.1, and that it will promptly
notify the Company of any changes in the information set forth in the
Registration Statement regarding the Purchaser or its plan of distribution.

                  7.3 Indemnification. For the purpose of this Section 7.3:

                  (i)   the term "Purchaser/Affiliate" shall mean any affiliates
                        of the Purchaser and any person who controls the
                        Purchaser or any affiliate of the Purchaser within the
                        meaning of Section 15 of the Securities Act or Section
                        20 of the Exchange Act; and

                  (ii)  the term "Registration Statement" shall include any
                        final prospectus, exhibit, supplement or amendment
                        included in or relating to, and any document
                        incorporated by reference in, the Registration Statement
                        referred to in Section 7.1.

                  (a) The Company agrees to indemnify and hold harmless each of
the Purchasers and each Purchaser/Affiliate, against any losses, claims,
damages, liabilities or expenses, joint or several, to which such Purchasers or
such Purchaser/Affiliates may become subject, under the Securities Act, the
Exchange Act, or any other federal or state statutory law or regulation, or at
common law or otherwise (including in settlement of any litigation, if such
settlement is effected with the written consent of the Company), insofar as such
losses, claims, damages, liabilities or expenses (or actions in respect thereof
as contemplated below) arise out of or are based upon any untrue statement or
alleged untrue statement of any material fact contained in the Registration
Statement, including the prospectus, financial statements and schedules, and all
other documents filed as a part thereof, as amended at the time of effectiveness
of the Registration Statement, including any information deemed to be a part
thereof as of the time of effectiveness pursuant to paragraph (b) of Rule 430A,
or pursuant to Rule 434, of the Rules and Regulations, or the prospectus, in the
form first filed with the Commission pursuant to Rule 424(b) of the Regulations,
or filed as part of the Registration Statement at the time of effectiveness if
no Rule 424(b) filing is required (the "Prospectus"), or any amendment or
supplement thereto, or arise out of or are based upon the omission or alleged
omission to state in any of them a material fact required to be stated therein
or necessary to make the statements in the Registration Statement or any
amendment or supplement thereto not misleading or in the Prospectus or any
amendment or supplement thereto not misleading in the light of the circumstances
under which they were made, or arise out of or are based in whole or in part on
any inaccuracy in the representations and warranties of the Company contained in
this Agreement, or any failure of the Company to perform its obligations
hereunder or under law, and will reimburse each Purchaser and each such
Purchaser/Affiliate for any legal and other expenses as such expenses are
reasonably incurred by such Purchaser or such Purchaser/Affiliate in connection
with investigating, defending, settling, compromising or paying any such loss,
claim, damage, liability, expense or action; provided, however, that the Company
will not be liable in any such case to the extent that any such loss, claim,


                                      -10-


damage, liability or expense arises out of or is based upon (i) an untrue
statement or alleged untrue statement or omission or alleged omission made in
the Registration Statement, the Prospectus or any amendment or supplement
thereto in reliance upon and in conformity with written information furnished to
the Company by or on behalf of the Purchaser expressly for use therein, or (ii)
the failure of such Purchaser to comply with the covenants and agreements
contained in Sections 5(b) or 7.2 hereof respecting the sale of the Underlying
Shares, or (iii) the inaccuracy of any representations made by such Purchaser
herein or (iv) any statement or omission in any Prospectus that is corrected in
any subsequent Prospectus that was delivered to the Purchaser prior to the
pertinent sale or sales by the Purchaser.

            (b) Each Purchaser will severally, but not jointly, indemnify and
hold harmless the Company, each of its directors, each of its officers who
signed the Registration Statement and each person, if any, who controls the
Company within the meaning of Section 15 of the Securities Act or Section 20 of
the Exchange Act, against any losses, claims, damages, liabilities or expenses
to which the Company, each of its directors, each of its officers who signed the
Registration Statement or controlling person may become subject, under the
Securities Act, the Exchange Act, or any other federal or state statutory law or
regulation, or at common law or otherwise (including in settlement of any
litigation, if such settlement is effected with the written consent of such
Purchaser) insofar as such losses, claims, damages, liabilities or expenses (or
actions in respect thereof as contemplated below) arise out of or are based upon
(i) any failure to comply with the covenants and agreements contained in
Sections 5(b) or 7.2 hereof respecting the sale of the Underlying Shares or (ii)
the inaccuracy of any representation made by such Purchaser herein or (iii) any
untrue or alleged untrue statement of any material fact contained in the
Registration Statement, the Prospectus, or any amendment or supplement thereto,
or arise out of or are based upon the omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements in the Registration Statement or any amendment or supplement thereto
not misleading or in the Prospectus or any amendment or supplement thereto not
misleading in the light of the circumstances under which they were made, in each
case to the extent, but only to the extent, that such untrue statement or
alleged untrue statement or omission or alleged omission was made in the
Registration Statement, the Prospectus, or any amendment or supplement thereto,
in reliance upon and in conformity with written information furnished to the
Company by or on behalf of any Purchaser expressly for use therein, and will
reimburse the Company, each of its directors, each of its officers who signed
the Registration Statement or controlling person for any legal and other expense
reasonably incurred by the Company, each of its directors, each of its officers
who signed the Registration Statement or controlling person in connection with
investigating, defending, settling, compromising or paying any such loss, claim,
damage, liability, expense or action.

            (c) Promptly after receipt by an indemnified party under this
Section 7.3 of notice of the threat or commencement of any action, such
indemnified party will, if a claim in respect thereof is to be made against an
indemnifying party under this Section 7.3 promptly notify the indemnifying party
in writing thereof; but the omission so to notify the indemnifying party will
not relieve it from any liability which it may have to any indemnified party for
contribution or otherwise than under the indemnity agreement contained in this
Section 7.3 or to the extent it is not prejudiced as a result of such failure.
In case any such action is brought against any indemnified party and such
indemnified party seeks or intends to seek indemnity from an indemnifying party,
the indemnifying party will be entitled to participate in, and, to the extent
that it may wish, jointly with all other indemnifying parties similarly
notified, to assume the defense thereof with counsel reasonably satisfactory to
such indemnified party; provided, however, if the defendants in any such action
include both the indemnified party, and the indemnifying party and the
indemnified party shall have reasonably concluded that there may be a conflict
of interest, based upon the advice of such indemnified party's counsel, between
the positions of the indemnifying party and the indemnified party in conducting
the defense of any such action or that there may be legal defenses available to
it and/or other indemnified parties which are different from or additional to
those available to the indemnifying party, the indemnified party or parties
shall have the right to select separate counsel to assume such legal defenses
and to otherwise participate in the defense of such action on behalf of such
indemnified party or parties. Upon receipt of notice from the indemnifying party
to such indemnified party of its election so to assume the defense of such
action and approval by the indemnified party of counsel, the indemnifying party
will not be liable to such indemnified party under this Section 7.3 for any
legal or other expenses subsequently incurred by such indemnified party in
connection with the defense thereof unless (i) the indemnified party shall have
employed such counsel in connection with the assumption of legal defenses in
accordance with the proviso to the preceding sentence (it being


                                      -11-


understood, however, that the indemnifying party shall not be liable for the
expenses of more than one separate counsel, approved by such indemnifying party
in the case of paragraph (a), representing the indemnified parties who are
parties to such action, plus local counsel, if appropriate) or (ii) the
indemnifying party shall not have employed counsel reasonably satisfactory to
the indemnified party to represent the indemnified party within a reasonable
time after notice of commencement of action, in each of which cases the
reasonable fees and expenses of counsel shall be at the expense of the
indemnifying party.

            (d) If the indemnification provided for in this Section 7.3 is
required by its terms but is for any reason held to be unavailable to or
otherwise insufficient to hold harmless an indemnified party under paragraphs
(a), (b) or (c) of this Section 7.3 in respect to any losses, claims, damages,
liabilities or expenses referred to herein, then each applicable indemnifying
party shall contribute to the amount paid or payable by such indemnified party
as a result of any losses, claims, damages, liabilities or expenses referred to
herein (i) in such proportion as is appropriate to reflect the relative benefits
received by the Company and the Purchaser from the placement of the Preferred
Stock contemplated by this Agreement or (ii) if the allocation provided by
clause (i) above is not permitted by applicable law, in such proportion as is
appropriate to reflect not only the relative benefits referred to in clause (i)
above but the relative fault of the Company and the Purchaser in connection with
the statements or omissions or inaccuracies in the representations and
warranties in this Agreement that resulted in such losses, claims, damages,
liabilities or expenses, as well as any other relevant equitable considerations.
The relative benefits received by the Company on the one hand and each Purchaser
on the other shall be deemed to be in the same proportion as the amount paid by
such Purchaser to the Company pursuant to this Agreement for the Shares
purchased by such Purchaser into which the Underlying Shares that were sold
pursuant to the Registration Statement were converted bears to the difference
(the "Difference") between the amount such Purchaser paid for the Shares
purchased by such Purchaser into which the Underlying Shares that were sold
pursuant to the Registration Statement were converted and the amount received by
such Purchaser from such sale of the Underlying Shares. The relative fault of
the Company on the one hand and each Purchaser on the other shall be determined
by reference to, among other things, whether the untrue or alleged statement of
a material fact or the omission or alleged omission to state a material fact or
the inaccurate or the alleged inaccurate representation and/or warranty relates
to information supplied by the Company or by such Purchaser and the parties'
relative intent, knowledge, access to information and opportunity to correct or
prevent such statement or omission. The amount paid or payable by a party as a
result of the losses, claims, damages, liabilities and expenses referred to
above shall be deemed to include, subject to the limitations set forth in
paragraph (c) of this Section 7.3, any legal or other fees or expenses
reasonably incurred by such party in connection with investigating or defending
any action or claim. The provisions set forth in paragraph (c) of this Section
7.3 with respect to the notice of the threat or commencement of any threat or
action shall apply if a claim for contribution is to be made under this
paragraph (d); provided, however, that no additional notice shall be required
with respect to any threat or action for which notice has been given under
paragraph (c) for purposes of indemnification. The Company and each Purchaser
agree that it would not be just and equitable if contribution pursuant to this
Section 7.3 were determined solely by pro rata allocation (even if the Purchaser
were treated as one entity for such purpose) or by any other method of
allocation which does not take account of the equitable considerations referred
to in this paragraph. Notwithstanding the provisions of this Section 7.3, no
Purchaser shall be required to contribute any amount in excess of the amount by
which the Difference exceeds the amount of any damages that such Purchaser has
otherwise been required to pay by reason of such untrue or alleged untrue
statement or omission or alleged omission. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. The Purchasers' obligations to contribute pursuant
to this Section 7.3 are several and not joint.

            7.4. Termination of Conditions and Obligations. The conditions
precedent imposed by Section 5 or this Section 7 upon the transferability of the
Shares and the Underlying Shares shall cease and terminate as to any particular
number of the Shares or Underlying Shares upon the passage of two years from the
effective date of the Registration Statement covering such Underlying Shares or
at such time as an opinion of counsel satisfactory in form and substance to the
Company shall have been rendered to the effect that such conditions are not
necessary in order to comply with the Securities Act.


                                      -12-


            7.5. Information Available. So long as the Registration Statement is
effective covering the resale of Underlying Shares owned by the Purchaser, the
Company will furnish to the Purchaser:

            (a)   as soon as practicable (but in the case of the Company's
                  Annual Report to Stockholders, within 150 days after the end
                  of each fiscal year of the Company), one copy of (i) its
                  Annual Report to Stockholders (which Annual Report shall
                  contain financial statements audited in accordance with
                  generally accepted accounting principles in the United States
                  of America by a firm of certified public accountants of
                  recognized standing), (ii) if not included in substance in the
                  Annual Report to Stockholders, upon the request of the
                  Purchaser, its Annual Report on Form 10-K, (iii) upon the
                  request of the Purchaser, each of its Quarterly Reports to its
                  stockholders and, if not included in substance in its
                  quarterly report to stockholders, its quarterly report on Form
                  10-Q, (iv) a copy of the Registration Statement (the
                  foregoing, in each case, excluding exhibits);

            (b)   upon the request of the Purchaser, all exhibits excluded by
                  the parenthetical to subparagraph (a)(v) of this Section 7.5;
                  and

            (c)   upon the request of the Purchaser, a reasonable number of
                  copies of the prospectuses to supply to any other party
                  requiring such prospectuses;

and the Company, upon the reasonable request of the Purchaser, will meet with
the Purchaser or a representative thereof at the Company's headquarters to
discuss information relevant for disclosure in the Registration Statement
covering the Underlying Shares and will otherwise reasonably cooperate with any
Purchaser conducting an investigation for the purpose of reducing or eliminating
such Purchaser's exposure to liability under the Securities Act, including the
reasonable production of information at the Company's headquarters, subject to
appropriate confidentiality limitations.

            SECTION 8. Broker's Fee. The Purchaser acknowledges that the Company
intends to pay to the Placement Agent a fee in respect of the sale of the Shares
to the Purchaser. Each of the parties hereto hereby represents that, on the
basis of any actions and agreements by it, there are no other brokers or finders
entitled to compensation in connection with the sale of the Shares to the
Purchaser.

            SECTION 9. Notices. All notices, requests, consents and other
communications hereunder shall be in writing, shall be mailed by first-class
registered or certified airmail, confirmed facsimile or nationally recognized
overnight express courier postage prepaid, and shall be deemed given when so
mailed and shall be delivered as addressed as follows:

            (a)   if to the Company, to:

                       Triangle Pharmaceuticals, Inc.
                       4 University Place
                       4611 University Drive
                       Durham, North Carolina 27707
                       Attn: Andrew Finkle, Esq.
                       Facsimile:  (919) 402-1192


                                      -13-


                  with a copy to:

                        Brobeck, Phleger & Harrison LLP
                        1633 Broadway
                        47th Floor
                        New York, New York  10019
                        Attention: Luci Staller Altman, Esq.
                        Telephone: (212) 237-2520
                        Facsimile: (212) 586-7878

                  or to such other person at such other place as the Company
                  shall designate to the Purchaser in writing; and

            (b)   if to the Purchaser, at its address as set forth at the end of
                  this Agreement, or at such other address or addresses as may
                  have been furnished to the Company in writing.

            SECTION 10. Changes. This Agreement may not be modified or amended
except pursuant to an instrument in writing signed by the Company and the
Purchaser.

            SECTION 11. Headings. The headings of the various sections of this
Agreement have been inserted for convenience of reference only and shall not be
deemed to be part of this Agreement.

            SECTION 12. Severability. In case any provision contained in this
Agreement should be invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein shall not in any way be affected or impaired thereby.

            SECTION 13. Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of New York and the federal
law of the United States of America.

            SECTION 14. Counterparts. This Agreement may be executed in two or
more counterparts, each of which shall constitute an original, but all of which,
when taken together, shall constitute but one instrument, and shall become
effective when one or more counterparts have been signed by each party hereto
and delivered to the other parties. Facsimile signatures shall be deemed
original signatures.

            SECTION 15. Entire Agreement. This Agreement and the instruments
referenced herein contain the entire understanding of the parties with respect
to the matters covered herein and therein and, except as specifically set forth
herein or therein, neither the Company nor the Purchaser makes any
representation, warranty, covenant or undertaking with respect to such matters.

            SECTION 16. Third Party Beneficiaries. This Agreement is intended
for the benefit of the parties hereto and their respective permitted successors
and assigns, and is not for the benefit of, nor may any provision hereof be
enforced by, any other person.


                                      -14-


            IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their duly authorized representatives as of the day and year
first above written.

                                            TRIANGLE PHARMACEUTICALS, INC.


                                            By:_________________________________
                                               Name:
                                               Title:

Print or Type:
                                            Name of Purchaser
                                              (Individual or Institution):

                                            ____________________________________

                                            Name of Individual
                                              representing Purchaser
                                              (if an Institution):

                                            ____________________________________

                                            Title of Individual
                                              representing Purchaser
                                              (if an Institution):

                                            ____________________________________

Signature by:
                                            Individual Purchaser or Individual
                                              representing Purchaser:

                                            ____________________________________

                                            Address:    ________________________

                                            Telephone:  ________________________

                                            Facsimile:  ________________________


                                      -15-


                     SUMMARY INSTRUCTION SHEET FOR PURCHASER

                   (to be read in conjunction with the entire
                        Purchase Agreement which follows)

A.    Complete the following items on BOTH Purchase Agreements:

      1.    Page 20 - Signature:

              (i) Name of Purchaser (Individual or Institution)
             (ii) Name of Individual representing Purchaser (if an Institution)
            (iii) Title of Individual representing Purchaser (if an Institution)
             (iv) Signature of Individual Purchaser or Individual representing
                  Purchaser

      2.    Appendix I - Stock Certificate Questionnaire:

            Provide the information requested by the Stock Certificate
            Questionnaire.

            Appendix I - Registration Statement Questionnaire:

            Provide the information requested by the Registration Statement
            Questionnaire.

      3.    Return BOTH properly completed and signed Purchase Agreements
            including the properly completed Appendix I to:

                     Banc of America Securities LLC
                     9 West 57th Street
                     New York, NY 10019
                     Attention: Isaac Osaki, Esq.

B.    Instructions regarding the transfer of funds for the purchase of Shares
      will be sent by facsimile to the Purchaser by the Placement Agent at a
      later date.

C.    Upon conversion of the Shares into Underlying Shares, the Purchaser shall,
      within 10 days, complete and deliver to the Company the Registration
      Statement Questionnaire, attached hereto as Appendix I, for use by the
      Company in preparation of the Registration Statement.

D.    Upon the resale of the Underlying Shares by the Purchasers after the
      Registration Statement covering the Underlying Shares is effective, as
      described in the Purchase Agreement, the Purchaser:

             (i)  must deliver a current prospectus of the Company to the buyer
                  (prospectuses must be obtained from the Company at the
                  Purchaser's request); and

            (ii)  must send a letter in the form of Appendix II to the Company
                  so that the Underlying Shares may be properly transferred.



                                                                      APPENDIX I
                                                                    (one of two)

TRIANGLE PHARMACEUTICALS, INC.

STOCK CERTIFICATE QUESTIONNAIRE

      Pursuant to Section 3 of the Agreement, please provide us with the
following information:

1.    The exact name that your Shares are to be
      registered in (this is the name that will appear
      on your stock certificate(s)).  You may use a
      nominee name if appropriate:                           ___________________

2.    The relationship between the Purchaser of the
      Shares and the Registered Holder listed
      in response to item 1 above:                           ___________________

3.    The mailing address of the Registered Holder
      listed in response to item 1 above:                    ___________________


                                                             ___________________


                                                             ___________________


                                                             ___________________

4.    The Social Security Number or Tax
      Identification Number of the Registered
      Holder listed in response to item 1 above:             ___________________



                                                                      APPENDIX I
                                                                    (two of two)

                         TRIANGLE PHARMACEUTICALS, INC.
                      REGISTRATION STATEMENT QUESTIONNAIRE

            In connection with the preparation of the Registration Statement,
please provide us with the following information:

            1. Pursuant to the "Selling Shareholder" section of the Registration
Statement, please state your or your organization's name exactly as it should
appear in the Registration Statement:

            2. Please provide the number of shares that you or your organization
will own immediately after Closing, including those Underlying Shares issued
upon conversion of the Shares purchased by you or your organization pursuant to
this Purchase Agreement and those shares of Common Stock purchased by you or
your organization through other transactions:

            3. Have you or your organization had any position, office or other
material relationship within the past three years with the Company or its
affiliates?

                       |_| Yes         |_| No

            If yes, please indicate the nature of any such relationships below:

               _________________________________________________________________

               _________________________________________________________________

               _________________________________________________________________



                                                                     APPENDIX II

Attention:

                   PURCHASER'S CERTIFICATE OF SUBSEQUENT SALE

      The undersigned, [an officer of, or other person duly authorized by]

________________________________________________________________________________
              [fill in official name of individual or institution]

hereby certifies that he/she [said institution] is the Purchaser of the shares
evidenced by the attached certificate, and as such, sold such shares on
________________ in accordance with
     [date]

Registration Statement number __________________________________________________
                                       [fill in the number of or otherwise

____________________________________________ and the requirement of delivering a
identify Registration Statement]

current prospectus by the Company has been complied with in connection with such
sale.

Print or Type:

          Name of Purchaser
            (Individual or
             Institution):       ______________________

          Name of Individual
            representing
            Purchaser (if an
            Institution)         ______________________

          Title of Individual
            representing
            Purchaser (if an
            Institution):        ______________________

Signature by:

          Individual Purchaser
            or Individual repre-
            senting Purchaser:   ______________________