Document:

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                                                                    Exhibit 4.19

                               BIOPURE CORPORATION

                                     WARRANT

Warrant No. BW -                                         Dated: January __, 2006

     Biopure Corporation, a Delaware corporation (the "COMPANY"), hereby
certifies that, for value received, _______. or its registered assigns
(including permitted transferees, the "HOLDER"), is entitled to purchase from
the Company up to a total of ______ shares (as adjusted from time to time as
provided in SECTION 9) of Common Stock (as defined below), together with the
associated preferred stock purchase rights under that certain Rights Agreement
(the "RIGHTS AGREEMENT") dated as of as of September 24, 1999 between the
Company and American Stock Transfer & Trust Company, as rights agent, to the
extent the Rights Agreement is in effect on the date of such purchase, at an
exercise price equal to $1.03 per share (as adjusted from time to time as
provided in SECTION 9, the "EXERCISE PRICE"), at any time and from time to time
from and after January 17, 2006 (the "INITIAL EXERCISE DATE") to and including
January 17, 2011 (the "EXPIRATION DATE"), and subject to the following terms and
conditions.

     1. DEFINITIONS. The capitalized terms used herein and not otherwise defined
shall have the meanings set forth below:

          "AFFILIATE" of any specified Person means any other person or entity
directly or indirectly controlling, controlled by or under direct or indirect
common control with such specified Person. For purposes of this definition,
"CONTROL" means the power to direct the management and policies of such Person
or firm, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise.

          "COMMISSION" means the United States Securities and Exchange
Commission.

          "COMMON STOCK" means the Class A common stock of the Company, $0.01
par value per share.

          "ELIGIBLE MARKET" means any of the New York Stock Exchange, the
American Stock Exchange or Nasdaq, and any successor markets thereto.

          "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended

          "MARKET PRICE" shall mean (i) if the principal trading market for such
securities is an exchange, the average of the last reported sale prices per
share for the last ten previous Trading Days in which a sale was reported, as
officially reported on any consolidated tape, (ii) if clause (i) is not
applicable, the average of the closing bid price per share for the last ten
previous Trading Days as set forth by Nasdaq or (iii) if clauses (i) and (ii)
are not applicable, the average of the closing bid price per share for the last
ten previous Trading Days as set forth in the National Quotation Bureau sheet
listing for such securities. Notwithstanding the foregoing, if there is no
reported sales price or closing bid price, as the case may be, on any of the ten
Trading Days preceding the event requiring a determination of Market Price
hereunder, then the Market Price shall be determined in good faith after
reasonable investigation by resolution of the Board of Directors of the Company.

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          "NASDAQ" means the Nasdaq Capital Market or Nasdaq National Market,
and any successor markets thereto.

          "OTHER SECURITIES" refers to any capital stock (other than Common
Stock) and other securities of the Company or any other Person which the Holder
of this Warrant at any time shall be entitled to receive, or shall have
received, pursuant to the terms hereof upon the exercise of this Warrant, in
lieu of or in addition to Common Stock.

          "PERSON" means any court or other federal, state, local or other
governmental authority or other individual or corporation, partnership, trust,
incorporated or unincorporated association, joint venture, limited liability
company, joint stock company, government (or an agency or subdivision thereof)
or other entity of any kind.

          "REGISTRATION STATEMENT" means the Company's Registration Statement
(File Nos. 333-114559), as such registration statements are amended,
supplemented or replaced.

          "TRADING DAY" means (a) any day on which the Common Stock is listed or
quoted and traded on any Eligible Market or (b) if the Common Stock is not then
quoted and traded on any Eligible Market, then a day on which trading occurs on
the Nasdaq National Market (or any successor thereto).

          "WARRANT SHARES" shall initially mean shares of Common Stock (together
with the associated preferred stock purchase rights under the Rights Agreement
to the extent the Rights Agreement is in effect on the applicable date) and in
addition may include Other Securities and Substituted Property (as defined in
SECTION 9(e)(x)) issued or issuable from time to time upon exercise of this
Warrant.

     2. REGISTRATION OF WARRANT. The Company shall register this Warrant, upon
records to be maintained by the Company for that purpose (the "WARRANT
REGISTER"), in the name of the record Holder hereof from time to time. The
Company may deem and treat the registered Holder of this Warrant as the absolute
owner hereof for the purpose of any exercise hereof or any distribution to the
Holder, and for all other purposes.

     3. REGISTRATION OF TRANSFERS. The Company shall register the transfer of
any portion of this Warrant in the Warrant Register, upon surrender of this
Warrant, with the Form of Assignment attached hereto as Appendix A duly
completed and signed, to the Company at its address specified herein. Upon any
such registration and transfer, a new warrant in substantially the form of a
Warrant (any such new warrant, a "NEW WARRANT"), evidencing the portion of this
Warrant so transferred shall be issued to the transferee and a New Warrant
evidencing the remaining portion of this Warrant not so transferred, if any,
shall be issued to the transferring Holder. The acceptance of the New Warrant by
the transferee thereof shall be deemed the acceptance by such transferee of all
of the rights and obligations of a holder of a Warrant.

     4. EXERCISE AND DURATION OF WARRANT.

        (a) This Warrant shall be exercisable, either in its entirety or for a
portion of the number of Warrant Shares, by the registered Holder at any time
and from time to time from and after the Initial Exercise Date to and including
the Expiration Date. At 5:00 P.M. New York City

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time on the Expiration Date, the portion of this Warrant not exercised prior
thereto shall be and become void and of no value, and the Holder hereof shall
have no right to purchase any additional Warrant Shares hereunder.

        (b) A Holder may exercise this Warrant by delivering to the Company, in
accordance with Section 13, this Warrant, together with (i) an exercise notice,
in the form attached hereto as APPENDIX B (the "EXERCISE NOTICE"), appropriately
completed and duly signed, and (ii) payment of the Exercise Price for the number
of Warrant Shares as to which this Warrant is being exercised (as set forth in
SECTION 4(c) below), and the date such items are received by the Company is an
"EXERCISE DATE." Execution and delivery of an Exercise Notice in respect of less
than all of the Warrant Shares issuable upon exercise of this Warrant shall
result in the cancellation of the original Warrant and issuance of a New Warrant
evidencing the right to purchase the remaining number of Warrant Shares.

        (c) The Holder shall pay the Exercise Price in cash, by certified bank
check payable to the order of the Company or by wire transfer of immediately
available funds in accordance with the Company's instructions.

        (d) Except as otherwise provided for herein, this Warrant shall not
entitle the Holder to any voting rights or other rights as a stockholder of the
Company by virtue of the ownership hereof.

        (e) Notwithstanding anything to the contrary herein, after the sixth
(6th) month anniversary of the date hereof, the Company may, by written notice
to the Holder, require that the Holder execute and deliver to the Company an
Exercise Notice exercising all of the Warrant Shares then held by such Holder
within twenty Business Days of the date of the Company's notice; provided,
however, that the Company may only provide such notice if the daily volume
weighted average price per share of the Common Stock for each of the ten
consecutive trading days ended immediately prior to the Company's notice is
equal to or greater than the Exercise Price multiplied by 1.5. At 5:00 P.M. New
York City time on such 20th Business Day, the portion of this Warrant not
exercised prior thereto shall be and become void and of no value, and the Holder
hereof shall have no right to purchase any additional Warrant Shares hereunder.

     5. DELIVERY OF WARRANT SHARES.

        (a) Upon exercise of this Warrant, the Company shall promptly issue or
cause to be issued and deliver or cause to be delivered to the Holder, in such
name or names as the Holder may designate, a certificate for the Warrant Shares
issuable upon such exercise (the "CERTIFICATE") bearing no restrictive legends.
The Holder, or any Person so designated by the Holder to receive the Warrant
Shares, shall be deemed to have become holder of record of such Warrant Shares
as of the Exercise Date.

        (b) The Warrant and the Warrant Shares will be registered pursuant to
the Registration Statement, and the Company covenants and agrees to maintain the
effectiveness of the Registration Statement until the Expiration Date.
Notwithstanding the foregoing, in the event that, prior to the Expiration Date,
the Company ceases to be eligible under the Securities Act of 1933, as amended
(the "ACT") or the rules and regulations promulgated thereunder, to maintain a
registration statement on Form S-3, or in the event that the Warrant or the
Warrant Shares cease to be eligible for inclusion in such Registration Statement
to the extent necessary to permit the Holder to exercise the Warrant and sell
the Warrant Shares without restriction under the Act, the

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Company will promptly (and in any event within 10 days of the date that the
Warrant or any Warrant Shares cease to be so eligible), amend or file a new
registration statement under the Act on a form eligible for use by the Company
for the registration of such securities and use its best efforts to have such
registration statement declared effective by the Commission as soon as
practicable after such filing, which registration statement shall include such
information as may be required to permit the exercise of the Warrant and the
sale of the Warrant Shares without restriction under the Act. The Holder
acknowledges and agrees that the Warrant shall be exercisable pursuant to any
such registration statement only at such times as the registration statement is
effective or in accordance with any applicable exemption from the registration
requirements of the Act. Upon such Registration Statement's being declared
effective by the Commission, the Company shall use its best efforts to cause the
Registration Statement to remain effective for a period of at least six (6)
consecutive months from the date that the Holders of the Warrants and Warrant
Shares covered by such Registration Statement are first given the opportunity to
sell all of such securities. In the event that ninety (90) days prior to the
Expiration Date, the Registration Statement registering the Warrant Shares is
not effective or is withdrawn or the Commission issues a stop order suspending
the effectiveness of such Registration Statement, the Company hereby agrees to
extend the Expiration Date for (x) an additional ninety (90) days or (y) until
the Registration Statement is declared effective by the SEC, whichever period is
longer. During such time as the Warrant Shares are registered pursuant to any
registration statement under the Act, the Company further covenants and agrees
to make timely filings of all documents required to be filed under the Act or
the Exchange Act in order to ensure that the registration statement, including
the documents incorporated by reference therein, if any, do not contain an
untrue statement of a material fact or omit to state any material fact required
to be stated therein or necessary in order to make the statements therein not
misleading.

        (c) This Warrant is exercisable, either in its entirety or, from time to
time, for a portion of the number of Warrant Shares. Upon surrender of this
Warrant following one or more partial exercises, the Company shall issue or
cause to be issued, at its expense, a New Warrant evidencing the right to
purchase the remaining number of Warrant Shares.

     6. CHARGES, TAXES AND EXPENSES. Issuance and delivery of certificates for
shares of Common Stock upon exercise of this Warrant shall be made without
charge to the Holder for any issue or transfer tax, withholding tax, transfer
agent fee or other incidental tax or expense in respect of the issuance of such
certificates, all of which taxes and expenses shall be paid by the Company;
provided, however, that the Company shall not be required to pay any tax which
may be payable in respect of any transfer involved in the issue, delivery or
registration of any certificates for Warrant Shares or Warrant in a name other
than that of the Holder and that the Holder will be required to pay any tax with
respect to cash received in lieu of fractional shares. The Holder shall be
responsible for all other tax liability that may arise as a result of holding or
transferring this Warrant or receiving Warrant Shares upon exercise hereof.

     7. REPLACEMENT OF WARRANT. If this Warrant is mutilated, lost, stolen or
destroyed, the Company, at the sole expense of the Holder (such expenses, if any
imposed by the Company to be reasonable), shall issue or cause to be issued in
exchange and substitution for and upon cancellation hereof, or in lieu of and in
substitution for this Warrant, a New Warrant, but only upon receipt of evidence
reasonably satisfactory to the Company of such loss, theft or destruction and
customary and reasonable indemnity, if requested by the Company.

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     8. RESERVATION OF WARRANT SHARES. The Company covenants that it will at all
times reserve and keep available out of the aggregate of its authorized but
unissued and otherwise unreserved Common Stock, solely for the purpose of
enabling it to issue Warrant Shares upon exercise of this Warrant as herein
provided, the number of Warrant Shares which are then issuable and deliverable
upon the exercise of this entire Warrant, free from all taxes, liens, claims,
encumbrances with respect to the issuance of such Warrant Shares and will not be
subject to any pre-emptive rights or similar rights (taking into account the
adjustments and restrictions of Section 9 hereof). The Company covenants that
all Warrant Shares so issuable and deliverable shall, upon issuance and the
payment of the applicable Exercise Price in accordance with the terms hereof, be
duly and validly authorized, issued, fully paid and nonassessable. The Company
will take all such action as may be necessary to assure that such shares of
Common Stock may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of any securities exchange
or automated quotation system upon which the Common Stock may be listed or
quoted, as the case may be; provided, however, that such actions shall only
require the Company's best efforts (or other specified standard) to the extent
specifically provided for in this Warrant.

     9. CERTAIN ADJUSTMENTS. The Exercise Price and number of Warrant Shares
issuable upon exercise of this Warrant are subject to adjustment from time to
time as set forth in this Section 9.

        (a) Stock Dividends. If the Company, at any time while this Warrant is
outstanding, pays a dividend on its Common Stock payable in additional shares of
Common Stock or otherwise makes a distribution on any class of capital stock
that is payable in shares of Common Stock, then in each such case the Exercise
Price shall be multiplied by a fraction, (A) the numerator of which shall be the
number of shares of Common Stock outstanding immediately prior to the opening of
business on the day after the record date for the determination of stockholders
entitled to receive such dividend or distribution and (B) the denominator of
which shall be the number of shares of Common Stock outstanding immediately
after the distribution date of such dividend or distribution. Any adjustment
made pursuant to this SECTION 9(a) shall become effective immediately after the
record date for the determination of stockholders entitled to receive such
dividend or distribution; PROVIDED, HOWEVER, that if following such record date
the Company rescinds or modifies such dividend or distribution, the Exercise
Price shall be appropriately adjusted (as of the date that the Company
effectively rescinds or modifies such dividend or distribution) to take into
account the effect of such rescinded or modified dividend or distribution on the
Exercise Price pursuant to this Section 9(a).

        (b) Stock Splits. If the Company, at any time while this Warrant is
outstanding, (i) subdivides outstanding shares of Common Stock into a larger
number of shares, or (ii) combines outstanding shares of Common Stock into a
smaller number of shares, then in each such case the Exercise Price shall be
multiplied by a fraction, (A) the numerator of which shall be the number of
shares of Common Stock outstanding immediately before such event and (B) the
denominator of which shall be the number of shares of Common Stock outstanding
immediately after such event. Any adjustment pursuant to this SECTION 9(b) shall
become effective immediately after the effective date of such subdivision or
combination.

        (c) Reclassifications. A reclassification of the Common Stock (other
than any such reclassification in connection with a merger or consolidation to
which SECTION 9(e) applies) into shares of any other class of stock shall be
deemed:

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          (i) a distribution by the Company to the holders of its Common Stock
of such shares of such other class of stock for the purposes and within the
meaning of this SECTION 9; and

          (ii) if the outstanding shares of Common Stock shall be changed into a
larger or smaller number of shares of Common Stock as part of such
reclassification, such change shall be deemed a subdivision or combination, as
the case may be, of the outstanding shares of Common Stock for the purposes and
within the meaning of SECTION 9(b).

        (d) Other Distributions. If the Company, at any time while this Warrant
is outstanding, distributes to holders of Common Stock (i) evidences of its
indebtedness, (ii) shares of any class of capital stock, (iii) rights or
warrants to subscribe for or purchase any shares of any class of capital stock
or (iv) any other asset, other than a distribution of Common Stock covered by
SECTION 9(a), (in each case, "DISTRIBUTED PROPERTY"), then in each such case the
Exercise Price in effect immediately prior to the record date fixed for
determination of stockholders entitled to receive such distribution (and the
Exercise Price thereafter applicable) shall be adjusted (effective on and after
such record date) to equal the product of such Exercise Price multiplied by a
fraction, (A) the numerator of which shall be Market Price on such record date
less the then fair market value of the Distributed Property distributed in
respect of one outstanding share of Common Stock, which, if the Distributed
Property is other than cash or marketable securities, shall be as determined in
good faith by the Board of Directors of the Company whose determination shall be
described in a board resolution, and (B) the denominator of which shall be the
Market Price on such record date; PROVIDED, HOWEVER, that if following the
record date for such distribution the Company rescinds or modifies such
distribution, the Exercise Price shall be appropriately adjusted (as of the date
that the Company effectively rescinds or modifies such distribution) to take
into account the effect of such rescinded or modified distribution on the
Exercise Price pursuant to this Section 9(d).

        (e) Fundamental Transactions. If, at any time following the Initial
Exercise Date, (i) the Company effects any merger or consolidation of the
Company with or into another Person, (ii) the Company effects any sale of all or
substantially all of its assets in one or a series of related transactions or
(iii) there shall occur any merger of another Person into the Company whereby
the Common Stock is cancelled, converted or reclassified into or exchanged for
other securities, cash or property (in any such case, a "FUNDAMENTAL
TRANSACTION"), then, as a condition to the consummation of such Fundamental
Transaction, the Company shall (or, in the case of any Fundamental Transaction
in which the Company is not the surviving entity, the Company shall take all
reasonable steps to cause such other Person to) execute and deliver to the
Holder of this Warrant a written instrument providing that:

          (x) so long as this Warrant remains outstanding, upon the exercise
hereof at any time on or after the consummation of such Fundamental Transaction
and on such terms and subject to such conditions as shall be nearly equivalent
as may be practicable to the provisions set forth in this Warrant, this Warrant
shall be exercisable into, in lieu of Common Stock issuable upon such exercise
prior to such consummation, the securities or other property (the "SUBSTITUTED
PROPERTY") that would have been received in connection with such Fundamental
Transaction by a holder of the number of shares of Common Stock into which this
Warrant was exercisable immediately prior to such Fundamental Transaction,
assuming such holder of Common Stock:

               (A) is not a Person with which the Company consolidated or into
which the Company merged or which merged into the Company or to which such sale
or transfer was made, as the case may be (a "CONSTITUENT PERSON"), or an
Affiliate of a Constituent Person; and

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               (B) failed to exercise such Holder's rights of election, if any,
as to the kind or amount of securities, cash and other property receivable in
connection with such Fundamental Transaction (provided, however, that if the
kind or amount of securities, cash or other property receivable in connection
with such Fundamental Transaction is not the same for each share of Common Stock
held immediately prior to such Fundamental Transaction by a Person other than a
Constituent Person or an Affiliate thereof and in respect of which such rights
of election shall not have been exercised (a "NON-ELECTING SHARE"), then, for
the purposes of this SECTION 9(e), the kind and amount of securities, cash and
other property receivable in connection with such Fundamental Transaction by
each Non-Electing Share shall be deemed to be the kind and amount so receivable
per share by a plurality of the Non-Electing Shares); and

          (y) the rights and obligations of the Company (or, in the event of a
transaction in which the Company is not the surviving Person, such other Person)
and the Holder in respect of Substituted Property shall be as nearly equivalent
as may be practicable to the rights and obligations of the Company and Holder in
respect of Common Stock hereunder.

        Such written instrument shall provide for adjustments which, for events
subsequent to the effective date of such written instrument, shall be as nearly
equivalent as may be practicable to the adjustments provided for in this SECTION
9. The above provisions of this SECTION 9(e) shall similarly apply to successive
Fundamental Transactions.

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        (f) Adjustment of Warrant Shares. Simultaneously with any adjustment to
the Exercise Price pursuant to paragraphs (a) through (d) of this SECTION 9, the
number of Warrant Shares that may be purchased upon exercise of this Warrant
shall be increased or decreased proportionately, so that after such adjustment
the aggregate Exercise Price payable hereunder for the increased or decreased
number of Warrant Shares shall be the same as the aggregate Exercise Price
payable for the Warrant Shares immediately prior to such adjustment.

        (g) Calculations. All calculations under this SECTION 9 shall be made to
the nearest cent or the nearest 1/100th of a share, as applicable. The number of
shares of Common Stock outstanding at any given time shall not include shares
owned or held by or for the account of the Company, and the disposition of any
such shares shall be considered an issue or sale of Common Stock.

        (h) Adjustments. Notwithstanding any provision of this SECTION 9, no
adjustment of the Exercise Price shall be required if such adjustment is less
than $0.01; provided, however, that any adjustments which by reason of this
SECTION 9(h) are not required to be made shall be carried forward and taken into
account for purposes of any subsequent adjustment required to be made hereunder.

        (i) Notice of Adjustments. Upon the occurrence of each adjustment
pursuant to this SECTION 9, the Company will promptly deliver to the Holder a
certificate executed by the Company's Chief Financial Officer setting forth, in
reasonable detail, the event requiring such adjustment and the method by which
such adjustment was calculated, the adjusted Exercise Price and the adjusted
number or type of Warrant Shares or other securities issuable upon exercise of
this Warrant (as applicable). The Company will retain at its office copies of
all such certificates and cause the same to be available for inspection at said
office during normal business hours by the Holder or any prospective purchaser
of the Warrant designated by the Holder.

        (j) Notice of Corporate Events. If the Company (i) declares a dividend
or any other distribution of cash, securities or other property in respect of
its Common Stock, including, without limitation, any granting of rights or
warrants to subscribe for or purchase any capital stock of the Company or any
subsidiary of the Company, (ii) authorizes, approves, enters into any agreement
contemplating, or solicits stockholder approval for, any Fundamental Transaction
or (iii) authorizes the voluntary dissolution, liquidation or winding up of the
affairs of the Company, then the Company shall deliver to the Holder a notice
describing the material terms and conditions of such transaction at least 15
calendar days prior to the applicable record or effective date on which a Person
would need to hold Common Stock in order to participate in or vote with respect
to such transaction, and the Company will take all steps reasonably necessary in
order to ensure that the Holder is given the practical opportunity to exercise
this Warrant prior to such time so as to participate in or vote with respect to
such transaction; provided, however, that the failure to deliver such notice or
any defect therein shall not affect the validity of the corporate action
required to be described in such notice.

     10. FRACTIONAL SHARES. The Company shall not be required to issue or cause
to be issued fractional Warrant Shares on the exercise of this Warrant. If any
fraction of a Warrant Share would, except for the provisions of this Section 10,
be issuable upon exercise of this Warrant, the Company shall make a cash payment
to the Holder equal to (a) such fraction multiplied by (b) the Market Price on
the Exercise Date of one full Warrant Share.

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     11. LISTING ON SECURITIES EXCHANGES. The Company has listed, and will use
its best efforts to maintain the listing of, the Warrant Shares on Nasdaq. In
furtherance and not in limitation of any other provision of this Warrant, if the
Company at any time shall list any Common Stock on any Eligible Market other
than Nasdaq, the Company will, at its expense, simultaneously list the Warrant
Shares (and use its best efforts to maintain such listing) on such Eligible
Market, upon official notice of issuance following the exercise of this Warrant;
and the Company will so list, register and use its best efforts to maintain such
listing on any Eligible Market any Other Securities, if and at the time that any
securities of like class or similar type shall be listed on such Eligible Market
by the Company.

     12. REMEDIES. The Company stipulates that the remedies at law of the Holder
of this Warrant 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.

     13. NOTICES. Any and all notices or other communications or deliveries
hereunder (including without limitation any Exercise Notice) shall be in writing
and shall be mailed by certified mail, return receipt requested, or by a
nationally recognized courier service or delivered (in person or by facsimile),
against receipt to the party to whom such notice or other communication is to be
given. Any notice or other communication given by means permitted by this
Section 13 shall be deemed given at the time of receipt thereof. The address for
such notices or communications shall be as set forth below:

     If to the Company:       Biopure Corporation
                              11 Hurley Street
                              Cambridge, MA 02141

     If to the Holder:        c/o Biopure Corporation
                              11 Hurley Street
                              Cambridge, MA 02141

Or such other address as is provided to such other party in accordance with this
Section 13.

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     14. WARRANT AGENT. The Company shall serve as warrant agent under this
Warrant. Upon a prompt written notice to the Holder, the Company may appoint a
new warrant agent. Any Person into which any new warrant agent may be merged,
any Person resulting from any consolidation to which any new warrant agent shall
be a party or any Person to which any new warrant agent transfers substantially
all of its corporate trust or shareholders services business shall be a
successor warrant agent under this Warrant without any further act. Any such
successor warrant agent shall promptly cause notice of its succession as warrant
agent to be mailed (by first class mail, postage prepaid) to the Holder at the
Holder's last address as shown on the Warrant Register.

     15. MISCELLANEOUS. (a) This Warrant may be assigned by the Holder. This
Warrant may not be assigned by the Company, except to a successor in the event
of a Fundamental Transaction. This Warrant shall be binding on and inure to the
benefit of the parties hereto and their respective successors and assigns.
Subject to the preceding sentence, nothing in this Warrant shall be construed to
give to any Person other than the Company and the Holder any legal or equitable
right, remedy or cause of action under this Warrant. This Warrant may be amended
only in writing signed by the Company and the Holder and their successors and
assigns.

        (b) The Company will not, by amendment of its governing documents or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
but will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such action as may be necessary or appropriate in order
to protect the rights of the Holder against impairment. Without limiting the
generality of the foregoing, the Company (i) will not increase the par value of
any Warrant Shares above the amount payable therefor upon exercise thereof, and
(ii) will take all such action as may be reasonably necessary or appropriate in
order that the Company may validly and legally issue fully paid and
nonassessable Warrant Shares on the exercise of this Warrant, free from all
taxes, liens, claims and encumbrances and (iii) will not close its shareholder
books or records in any manner which interferes with the timely exercise of this
Warrant.

        (c) This Warrant shall be governed by and construed and enforced in
accordance with the laws of the State of New York. Each party hereby irrevocably
submits to the exclusive jurisdiction of the state and Federal courts sitting in
the City of New York, Borough of Manhattan, for the adjudication of any dispute
hereunder or in connection herewith or with any transaction contemplated hereby
or discussed herein, and hereby irrevocably waives, and agrees not to assert in
any suit, action or proceeding that it is not personally subject to the
jurisdiction of any such court or that such suit, action or proceeding is
improper. Each party hereby irrevocably waives personal service of process and
consents to process being served in any such suit, action or proceeding by
mailing a copy thereof via registered or certified mail or overnight delivery
(with evidence of delivery) to such party at the address in effect for notices
to it under this Warrant and agrees that such service shall constitute good and
sufficient service of process and notice thereof. Nothing contained herein shall
be deemed to limit in any way any right to serve process in any manner permitted
by law. THE PARTIES HEREBY WAIVE ALL RIGHTS TO A TRIAL BY JURY.

        (d) Neither party shall be deemed in default of any provision of this
Warrant, to the extent that performance of its obligations or attempts to cure a
breach hereof are delayed or prevented by any event reasonably beyond the
control of such party, including, without

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limitation, war, hostilities, acts of terrorism, revolution, riot, civil
commotion, national emergency, strike, lockout, unavailability of supplies,
epidemic, fire, flood, earthquake, force of nature, explosion, embargo, or any
other Act of God, or any law, proclamation, regulation, ordinance, or other act
or order of any court, government or governmental agency, provided that such
party gives the other party written notice thereof promptly upon discovery
thereof and uses reasonable efforts to cure or mitigate the delay or failure to
perform.

        (e) The headings herein are for convenience only, do not constitute a
part of this Warrant and shall not be deemed to limit or affect any of the
provisions hereof.

        (f) In case any one or more of the provisions of this Warrant shall be
deemed invalid or unenforceable in any respect, the validity and enforceability
of the remaining terms and provisions of this Warrant shall not in any way be
affected or impaired thereby and the parties will attempt in good faith to agree
upon a valid and enforceable provision which shall be a commercially reasonable
substitute therefor, and upon so agreeing, shall incorporate such substitute
provision in this Warrant.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]

<PAGE>

     IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed
by its authorized officer as of the date first indicated above.

                                     BIOPURE CORPORATION

                                     By:
                                        ---------------------------------
                                        Name:
                                        Title:

<PAGE>

                                   APPENDIX A
                                   ----------

                               FORM OF ASSIGNMENT

           (to be completed and signed only upon transfer of Warrant)

     FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto ____________________ the right represented by the within Warrant to
purchase _____________ shares of Common Stock of Biopure Corporation to which
the within warrant relates and appoints __________________________ attorney to
transfer said right on the books of Biopure Corporation with full power of
substitution in the premises.

Dated:____________                    ------------------------------------------
                                      (Signature must conform in all respects to
                                      name of Holder as specified on face of the
                                      Warrant)

                                      Address of Transferee:

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

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

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

In the presence of:

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

<PAGE>

                                   APPENDIX B
                                   ----------

                             FORM OF EXERCISE NOTICE

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To:  Biopure Corporation

The undersigned is the Holder of Warrant No. [     ] (the "Warrant") issued by
Biopure Corporation, a Delaware corporation (the "Company"). Capitalized terms
used herein and not otherwise defined have the respective meanings set forth in
the Warrant.

1.   The Warrant is currently exercisable to purchase a total of _________
     Warrant Shares.

2.   The undersigned Holder hereby exercises its right to purchase _________
     Warrant Shares pursuant to the Warrant.

3.   The Holder shall pay the sum of $________ to the Company in accordance with
     the terms of the Warrant.

4.   Pursuant to this exercise, the Company shall deliver to the Holder Warrant
     Shares in accordance with the terms of the Warrant

5.   Following this exercise, the Warrant shall be exercisable to purchase a
     total of __________ Warrant Shares.

Dated: ____________                 Name of Holder:

                                    (Print)
                                           -------------------------------------

                                    By:
                                       -----------------------------------------

                                    Title:
                                          --------------------------------------

                                    (Signature must conform in all respects to
                                    name of Holder as specified on face of the
                                    Warrant)<PAGE>
                                                                    Exhibit 4.20

                                     WARRANT
                                       TO
                 PURCHASE ______ SHARES OF CLASS A COMMON STOCK
                                       OF
                               BIOPURE CORPORATION
                            (A DELAWARE CORPORATION)

Warrant No. ___

     THIS CERTIFIES THAT, for value received, _______ or its assigns, (the
"HOLDER"), as registered owner of this warrant (the "WARRANT"), is entitled to
purchase and receive, in whole or in part, subject to the provisions of this
Warrant, from Biopure Corporation, a Delaware corporation (the "COMPANY"), up to
____ fully paid, validly issued and nonassessable shares of Class A common
stock, par value $.01 per share (the "COMMON STOCK"), of the Company (the
"WARRANT SHARES") at a price per share equal to $0.984 (the "INITIAL EXERCISE
PRICE") (120% of the initial public offering price per share); provided,
however, that the number and kind of securities for which the Warrants are
exercisable are subject to further adjustment in certain events, such as
mergers, splits, stock dividends, recapitalizations and the like, to prevent
dilution, as set forth herein. This Warrant shall be exercisable at any time and
from time to time during the period commencing one (1) year after (the
"COMMENCEMENT DATE") the date of hereof up to and including January 17, 2011
(the "EXPIRATION DATE"), and subject to the terms and conditions set forth
herein. If the Expiration Date is a day on which banking institutions are
authorized by law to close, then this Warrant may be exercised on the next
succeeding day which is not such a day in accordance with the terms herein.
During the period beginning on the Commencement Date and ending on the
Expiration Date, the Company agrees not to take any action that would terminate
the Warrant.

     Section 1.  EXERCISE.

                 Section 1.1  EXERCISE FORM. In order to exercise this Warrant,
     the exercise form attached hereto must be duly executed and completed and
     delivered to the Company, together with this Warrant and payment of the
     Exercise Price in cash or by certified check or official bank check for the
     Warrant Shares being purchased. If the subscription rights represented
     hereby shall not be exercised at or before 5:00 p.m., Eastern time, on the
     Expiration Date, this Warrant shall become and be void without further
     force or effect, and all rights represented hereby shall cease and expire.

                 Section 1.2 CONVERSION RIGHT.

                    Section 1.2.1  DETERMINATION OF AMOUNT. In lieu of the
     payment of the Exercise Price in the manner required by Section 1.1, the
     Holder shall have the right (but not the obligation) to convert any
     exercisable but unexercised portion of this Warrant into Warrant Shares
     (the "CONVERSION RIGHT") as follows. Upon exercise of the Conversion Right,
     the Company shall deliver to the Holder (without payment by the Holder of
     any of the Exercise Price in cash) that number of Warrant Shares equal to
     the quotient obtained by dividing (x) the "VALUE" (as defined below), at
     the close of trading on the next to last trading day immediately preceding
     the exercise of the Conversion Right, of the portion of the Warrant being
     converted by (y) the "MARKET PRICE" (as defined below). The "VALUE" of the
     portion of the Warrant being converted shall equal the remainder derived
     from subtracting (a) the Exercise Price multiplied by the number of Warrant
     Shares underlying that portion of the Warrant being converted from (b) the
     Market Price of the

<PAGE>

     Warrant Shares multiplied by the number of Warrant Shares underlying that
     portion of the Warrant being converted. As used in this herein, the term
     "MARKET PRICE" at any date shall be deemed to be the sum of (A) the average
     last reported sale price of the shares for the five trading days ending on
     the next to last trading day immediately preceding the exercise of the
     Conversion Right as officially reported by the principal securities
     exchange on which the shares are listed or admitted to trading, or, if the
     shares are not listed or admitted to trading on any national securities
     exchange or if any such exchange on which the shares are listed is not its
     principal trading market, the average last reported sale price for such
     five trading days as furnished by the NASD through the Nasdaq National
     Market or Capital Market, or, if applicable, the OTC Bulletin Board, or if
     the shares are not listed or admitted to trading on any of the foregoing
     markets, or similar organization, as determined in good faith by resolution
     of the Board of Directors of the Company, based on the best information
     available to it AND (B) the intrinsic value of the Warrant using the share
     price determined in (A).

                    Section 1.2.2  MECHANICS OF CONVERSION. The Conversion Right
     may be exercised by the Holder on any business day on or after the
     Commencement Date and not later than the Expiration Date by delivering the
     Warrant with a duly executed exercise form attached hereto with the
     Conversion Right section completed to the Company, exercising the
     Conversion Right and specifying the total number of Warrant Shares that the
     Holder will purchase pursuant to such Conversion Right.

               Section 1.3  Notwithstanding anything to the contrary herein,
after the sixth (6th) month anniversary of the date hereof, the Company may, by
written notice to the Holder, require that the Holder execute and deliver to the
Company an Exercise Notice exercising all of the Warrant Shares then held by
such Holder within twenty (20) Business Days of the date of the Company's
notice; provided, however, that the Company may only provide such notice if the
daily volume weighted average price per share of the Common Stock for each of
the ten (10) consecutive trading days ended immediately prior to the Company's
notice is equal to or greater than the Exercise Price multiplied by 1.5. At 5:00
P.M. New York City time on such twentieth (20th) Business Day, the portion of
this Warrant not exercised prior thereto shall be and become void and of no
value, and the Holder hereof shall have no right to purchase any additional
Warrant Shares hereunder.

                                       2
<PAGE>

     Section 2.  TRANSFER.

                 Section 2.1  GENERAL RESTRICTIONS. The registered Holder of
     this Warrant, by its acceptance hereof, agrees that it will not sell,
     transfer or assign or hypothecate this Warrant prior to the one hundred
     eighty (180) days from the Effective Date to anyone other than (i) an
     officer or partner of such Holder, (ii) an officer of either Dawson James
     Securities, Inc. or Noble International Investments, Inc., the underwriters
     of the public offering with respect to which this Warrant has been issued
     ("UNDERWRITERS") or an officer or partner of any selected dealer in
     connection with the Company's public offering with respect to which this
     Warrant has been issued, or (iii) any selected dealer. On and after the
     Commencement Date, transfers to others may be made subject to compliance
     with or exemptions from applicable securities laws. In order to make any
     permitted assignment, the Holder must deliver to the Company the assignment
     form attached hereto duly executed and completed, together with the Warrant
     and payment of all transfer taxes, if any, payable in connection therewith.
     The Company shall immediately transfer this Warrant on the books of the
     Company and shall execute and deliver a new Warrant of like tenor to the
     appropriate assignee(s) expressly evidencing the right to purchase the
     aggregate number of Warrant Shares purchasable hereunder or such portion of
     such number as shall be contemplated by any such assignment.

                 Section 2.2  RESTRICTIONS IMPOSED BY THE ACT. This Warrant
     and the Warrant Shares underlying this Warrants shall not be transferred
     unless and until (i) the Company has received the opinion of counsel for
     the Holder that this Warrant or the Warrant Shares, as the case may be, may
     be transferred pursuant to an exemption from registration under the Act and
     applicable state law, the availability of which is established to the
     reasonable satisfaction of the Company (the Company hereby agreeing that an
     opinion of Cozen O'Connor shall be deemed satisfactory evidence of the
     availability of an exemption), or (ii) a registration statement relating to
     such Warrant or Warrant Shares, as the case may be, has been filed by the
     Company and declared effective by the Securities and Exchange Commission
     (the "COMMISSION") and compliance with applicable state law.

     Section 3.  NEW WARRANTS TO BE ISSUED.

                 Section 3.1  PARTIAL EXERCISE OR TRANSFER. Subject to the
     restrictions in Section 3 hereof, this Warrant may be exercised or assigned
     in whole or in part. In the event of the exercise or assignment hereof in
     part only, upon surrender of this Warrant for cancellation, together with
     the duly executed exercise or assignment form and funds sufficient to pay
     any Exercise Price and/or transfer tax, the Company shall cause to be
     delivered to the Holder without charge a new Warrant of like tenor to this
     Warrant in the name of the Holder evidencing the right of the Holder to
     purchase the aggregate number of Warrant Shares purchasable hereunder as to
     which this Warrant has not been exercised or assigned.

                 Section 3.2  LOST CERTIFICATE. Upon receipt by the Company of
     evidence satisfactory to it of the loss, theft, destruction or mutilation
     of this Warrant and of reasonably satisfactory indemnification, and upon
     surrender and cancellation of the Warrants, if mutilated, the Company shall
     execute and deliver a new Warrant of like tenor and date. Any such new
     Warrant executed and delivered as a result of such loss, theft, mutilation
     or destruction shall constitute a substitute contractual obligation on the
     part of the Company.

                                       3
<PAGE>

     Section 4.  REGISTRATION RIGHTS.

                 Section 4.1  REGISTRATION. This Warrant and the Warrant
     Shares issuable upon exercise of the Warrant (the Warrant and Warrant
     Shares collectively referred to hereinafter as the "REGISTRABLE
     SECURITIES") shall be registered pursuant to the Registration Statement (as
     defined hereinbelow), and the Company covenants and agrees to maintain the
     effectiveness of the Registration Statement until the Expiration Date.
     Notwithstanding the foregoing, in the event that, prior to the Expiration
     Date, the Company ceases to be eligible under the Securities Act of 1933,
     as amended (the "ACT") or the rules and regulations promulgated thereunder,
     to maintain a registration statement on Form S-3, or in the event that the
     Warrant or the Warrant Shares cease to be eligible for inclusion in such
     Registration Statement to the extent necessary to permit the Holder to
     exercise the Warrants and sell the Warrant Shares without restriction under
     the Act, the Company will promptly (and in any event within 10 days of the
     date that the Warrants or any Warrant Shares cease to be so eligible),
     amend or file a new registration statement under the Act on a form eligible
     for use by the Company for the registration of such securities and use its
     best efforts to have such registration statement declared effective by the
     Commission as soon as practicable after such filing, which registration
     statement shall include such information as may be required to permit the
     exercise of the Warrant and the sale of the Warrant Shares without
     restriction under the Act. The Holder acknowledges and agrees that the
     Warrant shall be exercisable pursuant to any such registration statement
     only at such times as the registration statement is effective or in
     accordance with any applicable exemption from the registration requirements
     of the Act. Upon such Registration Statement's being declared effective by
     the Commission, the Company shall use its best efforts to cause the
     Registration Statement to remain effective for a period of at least six (6)
     consecutive months from the date that the holders of the Warrant and the
     Warrant Shares are covered by such Registration Statement are first given
     the opportunity to sell all of such securities. During such time as the
     Warrant Shares registered pursuant to any registration statement under the
     Act, the Company further covenants and agrees to make timely filings of all
     documents required by be filed under the Act or the Exchange Act in order
     to ensure that the registration statement, including the documents
     incorporated by reference therein, if any, do not contain an untrue
     statement of a material fact or omit to state any material fact required to
     be stated therein or necessary in order to make the statements therein not
     misleading.

     "REGISTRATION STATEMENT" means the Company's Registration Statement (File
Nos. 333-114559), as such registration statements are amended, supplemented, or
replaced.

                                       4
<PAGE>

                 Section 4.2  EXPENSES. The Company shall bear all fees and
     expenses attendant to registering the Registrable Securities.

                 Section 4.3  EXERCISE OF WARRANTS. Nothing contained in this
     Warrant shall be construed as requiring the Holder(s) to exercise their
     Warrants prior to or after the initial filing of any registration statement
     or the effectiveness thereof.

                 Section 4.4  DOCUMENTS TO BE DELIVERED BY HOLDER(S). Each of
     the Holder(s) participating in any of the foregoing offerings shall furnish
     to the Company a completed and executed questionnaire provided by the
     Company requesting information customarily sought of selling
     securityholders.

                 Section 4.5  REMEDIES. The Company stipulates that the remedies
     at law of the Holder of this Warrant 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
     restraining any breach, actual or threatened, of the terms of this Warrant,
     without the necessity of showing economic loss. The remedies provided
     herein shall be cumulative and in addition to all other remedies available
     under this Warrant, at law or in equity, and nothing herein shall limit the
     right of the Holder to pursue actual damages for any failure by the Company
     to comply with the terms of the Warrant.

     Section 5.  ADJUSTMENTS.

                 Section 5.1  ADJUSTMENTS TO EXERCISE PRICE AND NUMBER OF
     SECURITIES. The Exercise Price and the number of the Warrant Shares
     underlying the Warrant shall be subject to adjustment from time to time as
     hereinafter set forth:

                    Section 5.1.1  If after the date hereof, and subject to the
     provisions of Section 5.2 below, the number of outstanding shares of Common
     Stock is increased by a stock dividend payable in shares of Common Stock or
     by a split-up of shares of Common Stock or other similar event, then, on
     the effective date thereof, the number of shares of Common Stock underlying
     the Warrant shall be increased in proportion to such increase in
     outstanding shares.

                    Section 5.1.2  If after the date hereof, and subject to the
     provisions of Section 5.2, the number of outstanding shares of Common Stock
     is decreased by a consolidation, combination or reclassification of shares
     of Common Stock or other similar event, then, on the effective date
     thereof, the number of shares of Common Stock underlying the Warrant shall
     be decreased in proportion to such decrease in outstanding shares.

                    Section 5.1.3  In case of any reclassification or
     reorganization of the outstanding shares of Common Stock other than a
     change covered by Section 5.1.1 or 5.1.2 hereof or that solely affects the
     par value of such shares of Common Stock, or in the case of any merger or
     consolidation of the Company with or into another corporation (other than a
     consolidation or merger in which the Company is the continuing corporation
     and that does not result in any reclassification or reorganization of the
     outstanding shares of Common Stock), or in the case of any sale or
     conveyance to another corporation or entity of the property of the Company
     as an entirety or substantially as an entirety in connection with which the
     Company is dissolved, the Holder of this Warrant shall have the right
     thereafter (until the expiration of the right of exercise of this Warrant)
     to receive upon the exercise hereof, for the same aggregate Exercise Price
     payable hereunder immediately prior to such event, the kind and amount of
     shares of stock or other

                                       5
<PAGE>

     securities or property (including cash) receivable upon such
     reclassification, reorganization, merger or consolidation, or upon a
     dissolution following any such sale or transfer, by a Holder of the number
     of shares of Common Stock of the Company obtainable upon exercise of this
     Warrant immediately prior to such event; and if any reclassification also
     results in a change in shares of Common Stock covered by Section 5.1.1 or
     5.1.2, then such adjustment shall be made pursuant to Sections 5.1.1, 5.1.2
     and this Section 5.1.3. The provisions of this Section 5.1.3 shall
     similarly apply to successive reclassifications, reorganizations, mergers
     or consolidations, sales or other transfers.

                    Section 5.1.4  This form of Warrant need not be changed
     because of any change pursuant to this Section, and Warrants issued after
     such change may state the same Exercise Price and the same number of
     Warrant Shares as are stated in the Warrant initially issued pursuant to
     this Agreement. The acceptance by any Holder of the issuance of new Warrant
     reflecting a required or permissive change shall not be deemed to waive any
     rights to an adjustment occurring after the Commencement Date or the
     computation thereof.

                    Section 5.1.5  In case of any consolidation of the Company
     with, or merger of the Company with, or merger of the Company into, another
     corporation (other than a consolidation or merger which does not result in
     any reclassification or change of the outstanding Common Stock), the
     corporation formed by such consolidation or merger shall execute and
     deliver to the Holder a replacement Warrant providing that the holder of
     each Warrant then outstanding or to be outstanding shall have the right
     thereafter (until the stated expiration of such Warrant) to receive, upon
     exercise of such Warrant the kind and amount of shares of stock and other
     securities and property receivable upon such consolidation or merger, by a
     holder of the number of shares of Common Stock of the Company for which
     such Warrant might have been exercised immediately prior to such
     consolidation, merger, sale or transfer. Such replacement Warrant shall
     provide for adjustments which shall be identical to the adjustments
     provided in Section 5. The above provision of this Section shall similarly
     apply to successive consolidations or mergers.

                 Section 5.2  ELIMINATION OF FRACTIONAL INTERESTS. The Company
     shall not be required to issue certificates representing fractions of
     shares of Common Stock or Warrants upon the exercise of the Warrant, nor
     shall it be required to issue scrip or pay cash in lieu of any fractional
     interests, it being the intent of the parties that all fractional interests
     shall be eliminated by rounding any fraction down to the nearest whole
     number of Warrants, shares of Common Stock or other securities, properties
     or rights.

     Section 6.  RESERVATION AND LISTING.

                 The Company shall at all times reserve and keep available out
     of its authorized shares of Common Stock, solely for the purpose of
     issuance upon exercise of the Warrant such number of shares of Common Stock
     or other securities, properties or rights as shall be issuable upon the
     exercise thereof. The Company covenants and agrees that, upon exercise of
     the Warrant and payment of the Exercise Price therefor, all shares of
     Common Stock and other securities issuable upon such exercise shall be duly
     and validly issued, fully paid and non-assessable and not subject to
     preemptive rights of any stockholder. As long as the Warrant shall be
     outstanding, the Company shall use its best efforts to cause all Warrant
     Shares issuable upon exercise of the Warrant to be listed (subject to
     official notice of issuance) on all securities exchanges (or, if applicable
     on the Nasdaq National Market, Capital Market, OTC Bulletin Board or any
     successor trading market) on which the Common Stock or the Public Warrants
     issued to the public in connection herewith may then be listed and/or
     quoted.

                                       6
<PAGE>

     Section 7.  CERTAIN NOTICE REQUIREMENTS.

                 Section 7.1  HOLDER'S RIGHT TO RECEIVE NOTICE. Nothing herein
     shall be construed as conferring upon the Holder the right to vote or
     consent as a stockholder for the election of directors or any other matter,
     or as having any rights whatsoever as a stockholder of the Company. If,
     however, at any time prior to the expiration of the Warrant and its
     exercise, any of the events described in Section 7.2 shall occur, then, in
     one or more of said events, the Company shall give written notice of such
     event at least fifteen (15) days prior to the date fixed as a record date
     or the date of closing the transfer books for the determination of the
     stockholders entitled to such dividend, distribution, conversion or
     exchange of securities or subscription rights, or entitled to vote on such
     proposed dissolution, liquidation, winding up or sale. Such notice shall
     specify such record date or the date of the closing of the transfer books,
     as the case may be. Notwithstanding the foregoing, the Company shall
     deliver to the Holder a copy of each notice given to the other stockholders
     of the Company at the same time and in the same manner that such notice is
     given to the stockholders.

                 Section 7.2  ENUMERATED EVENTS. The Company shall be required
     to give the notice described in this Section 7 upon one or more of the
     following events: (i) if the Company shall take a record of the holders of
     its shares of Common Stock for the purpose of entitling them to receive a
     dividend or distribution payable otherwise than in cash, or a cash dividend
     or distribution payable otherwise than out of retained earnings, as
     indicated by the accounting treatment of such dividend or distribution on
     the books of the Company, or (ii) the Company shall offer to all the
     holders of its Common Stock any additional shares of capital stock of the
     Company or securities convertible into or exchangeable for shares of
     capital stock of the Company, or any option, right or warrant to subscribe
     therefor, or (iii) a dissolution, liquidation or winding up of the Company
     (other than in connection with a consolidation or merger) or a sale of all
     or substantially all of its property, assets and business shall be proposed
     by the Company.

                 Section 7.3  CHANGE IN EXERCISE PRICE. The Company shall,
     promptly after an event requiring a change in the Exercise Price pursuant
     to Section 7 hereof, send notice to the Holder of such event and change
     (the "PRICE NOTICE"). The Price Notice shall describe the event causing the
     change and the method of calculating same and shall be certified as being
     true and accurate by the Company's President and Chief Financial Officer.

                 Section 7.4  TRANSMITTAL OF NOTICES. All notices, requests,
     consents and other communications under this Warrant shall be in writing
     and shall be deemed to have been duly made on the date of delivery if
     delivered personally or sent by overnight courier, with acknowledgement of
     receipt to the party to which notice is given, or on the fifth day after
     mailing if mailed to the party to whom notice is to be given, by registered
     or certified mail, return receipt requested, postage prepaid and properly
     addressed as follows: (i) if to the registered Holder of the Warrant, to
     the address of such Holder as shown on the books of the Company, or (ii) if
     to the Company, to its principal executive office.

     Section 8.  MISCELLANEOUS.

                 Section 8.1  AMENDMENTS. The Company and the Underwriters may
     from time to time supplement or amend this Warrant without the approval of
     any of the Holders in order to cure any ambiguity, to correct or supplement
     any provision contained herein which may be defective or inconsistent with
     any other provisions herein, or to make any other provisions in regard to
     matters or questions arising hereunder which the Company and the
     Underwriters may deem necessary or desirable and which the Company and the
     Underwriters deem shall not

                                       7
<PAGE>

     adversely affect the interest of the Holders. All other modifications or
     amendments shall require the written consent of the party against whom
     enforcement of the modification or amendment is sought.

                 Section 8.2  HEADINGS. The headings contained herein are for
     the sole purpose of convenience of reference, and shall not in any way
     limit or affect the meaning or interpretation of any of the terms or
     provisions of this Warrant.

                 Section 8.3  ENTIRE AGREEMENT. This Warrant (together with the
     other agreements and documents being delivered pursuant to or in connection
     with this Warrant) constitutes the entire agreement of the parties hereto
     with respect to the subject matter hereof, and supersedes all prior
     agreements and understandings of the parties, oral and written, with
     respect to the subject matter hereof.

                 Section 8.4  BINDING EFFECT. This Warrant shall inure solely to
     the benefit of and shall be binding upon, the Holder and the Company and
     their respective successors, legal representatives and assigns, and no
     other person shall have or be construed to have any legal or equitable
     right, remedy or claim under or in respect of or by virtue of this Warrant
     or any provisions herein contained.

                                       8
<PAGE>

                 Section 8.5  GOVERNING LAW; SUBMISSION TO JURISDICTION. This
     Warrant shall be governed by and construed and enforced in accordance with
     the laws of the State of New York, without giving effect to conflict of
     laws. The Company hereby agrees that any action, proceeding or claim
     against it arising out of, or relating in any way to this Warrant shall be
     brought and enforced in the courts of the State of New York or of the
     United States of America for the Southern District of New York, and
     irrevocably submits to such jurisdiction, which jurisdiction shall be
     exclusive. The Company hereby waives any objection to such exclusive
     jurisdiction and that such courts represent an inconvenient forum. Any
     process or summons to be served upon the Company may be served by
     transmitting a copy thereof by registered or certified mail, return receipt
     requested, postage prepaid, addressed to BIOPURE CORPORATION, 11 HURLEY
     STREET, CAMBRIDGE, MA 02141, ATTN: JANE KOBER, ESQ. Such mailing shall be
     deemed personal service and shall be legal and binding upon the Company in
     any action, proceeding or claim. The Company and the Holder, by acceptance
     hereof, agree that the prevailing party(ies) in any such action shall be
     entitled to recover from the other party(ies) all of its reasonable
     attorneys' fees and expenses relating to such action or proceeding and/or
     incurred in connection with the preparation therefor.

                 Section 8.6  WAIVER, Etc. The failure of the Company or the
     Holder to at any time enforce any of the provisions of this Warrant shall
     not be deemed or construed to be a waiver of any such provision, nor to in
     any way affect the validity of this Warrant or any provision hereof or the
     right of the Company or any Holder to thereafter enforce each and every
     provision of this Warrant. No waiver of any breach, non-compliance or
     non-fulfillment of any of the provisions of this Warrant shall be effective
     unless set forth in a written instrument executed by the party or parties
     against whom or which enforcement of such waiver is sought; and no waiver
     of any such breach, non-compliance or non-fulfillment shall be construed or
     deemed to be a waiver of any other or subsequent breach, non-compliance or
     non-fulfillment.

     IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by its
duly authorized officer as of the __th day of January 2006.

                                               BIOPURE CORPORATION

                                               By:
                                                  ------------------------------

                   (Signature Page Underwriters' Warrant UW-3)

                                       9
<PAGE>

FORM TO BE USED TO EXERCISE WARRANT:

Biopure Corporation

Date:_________________, 200__

     The undersigned hereby elects irrevocably to exercise the within Warrant
and to purchase ____ Biopure Corporation and hereby makes payment of
$____________ (at the rate of $_________ per Share) in payment of the Exercise
Price pursuant thereto. Please issue the Share as to which this Warrant is
exercised in accordance with the instructions given below.

OR

     The undersigned hereby elects irrevocably to exercise the within Warrant
and to purchase _________ Biopure Corporation by surrender of the unexercised
portion of the within Warrant (with a "Value" of $_______ based on a "Market
Price" of $__________.) Please issue the Warrant Shares as to which this Warrant
is exercised in accordance with the instructions given below.

                                                     ---------------------------
                                                     Signature

     NOTICE: THE SIGNATURE TO THIS FORM MUST CORRESPOND WITH THE NAME AS WRITTEN
UPON THE FACE OF THE WITHIN WARRANT IN EVERY PARTICULAR WITHOUT ALTERATION OR
ENLARGEMENT OR ANY CHANGE WHATSOEVER.

                   INSTRUCTIONS FOR REGISTRATION OF SECURITIES

Name
    -------------------------------------------------------
                  (Print in Block Letters)

Address
       ------------------------------------------------------------------

                                       10
<PAGE>

Form to be used to assign Warrant:

                                   ASSIGNMENT

     (To be executed by the registered Holder to effect a transfer of the within
Warrant):

     FOR VALUE RECEIVED,________________________ does hereby sell, assign and
transfer unto _______________________ the right to purchase __________________
_____ of Biopure Corporation ("Company") evidenced by the within Warrant and
does hereby authorize the Company to transfer such right on the books of the
Company.

Dated:___________________, 200_

                                           -------------------------------------
                                           Signature

-------------------------------------
Signature Guaranteed

     NOTICE: THE SIGNATURE TO THIS FORM MUST CORRESPOND WITH THE NAME AS WRITTEN
UPON THE FACE OF THE WITHIN WARRANT IN EVERY PARTICULAR WITHOUT ALTERATION OR
ENLARGEMENT OR ANY CHANGE WHATSOEVER, AND MUST BE GUARANTEED BY A BANK, OTHER
THAN A SAVINGS BANK, OR BY A TRUST COMPANY OR BY A FIRM HAVING MEMBERSHIP ON A
REGISTERED NATIONAL SECURITIES EXCHANGE.

                                       11

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