Document:

Exhibit 4.2

MOLECULIN BIOTECH, INC.

 

AGENT WARRANT TO PURCHASE COMMON STOCK

 

Warrant No.: [•]

Number of Shares of Common Stock: 525,000

Date of Issuance:  February 10, 2020 (“Issuance
Date”)

 

Moleculin Biotech, Inc.,
a company organized under the laws of Delaware (the “Company”), hereby certifies that, for good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, Oppenheimer & Co. Inc., the registered holder
hereof or its permitted assigns (the “Holder”), is entitled, subject to the terms set forth below, to purchase
from the Company, at the Exercise Price (as defined below) then in effect, at any time or times on or after August 11, 2020 (the
 “Initial Exercisability Date”), but not after 11:59 p.m., New York time, on the Expiration Date, (as defined
below), Five Hundred Twenty-Five Thousand (525,000) fully paid non-assessable shares of Common Stock (as defined below), subject
to adjustment as provided herein (the “Warrant Shares”).  Except as otherwise defined herein, capitalized
terms in this Agent Warrant to Purchase Common Stock (including any Agent Warrants to Purchase Common Stock issued in exchange,
transfer or replacement hereof, this “Warrant”), shall have the meanings set forth in Section 16. 
This Warrant is issued pursuant to (i) that certain Placement Agent Agreement (the “Placement Agent Agreement”),
dated as of February 6, 2020 (the “Effective Date”) by and between the Company and Oppenheimer & Co.
Inc., (ii) the Company’s Registration Statement on Form S-3 (File number 333-219434) (the “Registration Statement”)
and (iii) the Company’s prospectus supplement dated February 6, 2020.

 

     

     

    

 

1. EXERCISE OF WARRANT.

 

(a) Mechanics
of Exercise.  Subject to the terms and conditions hereof (including, without limitation, the limitations set forth
in Section 1(f)), this Warrant may be exercised by the Holder at any time or times on or after the Initial
Exercisability Date, in whole or in part (but not as to fractional shares), by delivery (via electronic mail) of a written
notice, in the form attached hereto as Exhibit A (the “Exercise Notice”), of the
Holder’s election to exercise this Warrant.  Within one (1) Trading Day following the delivery of the
Exercise Notice, the Holder shall make payment to the Company of an amount equal to the Exercise Price in effect on the date
of such exercise multiplied by the number of Warrant Shares as to which this Warrant is being exercised (the
 “Aggregate Exercise Price”) in cash by wire transfer of immediately available funds (a “Cash
Exercise”) or, if the provisions of Section 1(d) are applicable, by notifying the Company that this
Warrant is being exercised pursuant to a Cashless Exercise (as defined in Section 1(d)).  The Holder shall not be
required to deliver the original Warrant in order to effect an exercise hereunder, nor shall any ink-original signature or
medallion guarantee (or other type of guarantee or notarization) with respect to any Exercise Notice be required, provided,
that in the event of an exercise of this Warrant for all Warrant Shares then issuable hereunder, this Warrant is surrendered
to the Company by the fifth (5th) Trading Day following the date on which the Company has received each of the Exercise
Notice and, if this Warrant is being exercise pursuant to a Cash Exercise, the Aggregate Exercise Price.  Execution and
delivery of the Exercise Notice with respect to less than all of the Warrant Shares shall have the same effect as
cancellation of the original Warrant and issuance of a new Warrant evidencing the right to purchase the remaining number of
Warrant Shares.  On or before the first (1st) Trading Day following the date on which the Holder has delivered the
applicable Exercise Notice, the Company shall transmit by facsimile or electronic mail an acknowledgment of confirmation of
receipt of the Exercise Notice, in the form attached to the Exercise Notice, to the Holder and the Company’s transfer
agent (the “Transfer Agent”).  So long as the Holder delivers the Aggregate Exercise Price (or notice
of a Cashless Exercise) on or prior to the first (1st) Trading Day following the date on which the Exercise Notice has been
delivered to the Company, then on or prior to the earlier of (i) the second (2nd) Trading Day  and (ii) the
number of Trading Days comprising the Standard Settlement Period, in each case following the date on which the Exercise
Notice has been delivered to the Company, or, if the Holder does not deliver the Aggregate Exercise Price (or notice of a
Cashless Exercise) on or prior to the first (1st) Trading Day following the date on which the Exercise Notice has been
delivered to the Company, then on or prior to the first (1st) Trading Day following the date on which the Aggregate Exercise
Price (or notice of a Cashless Exercise) is delivered (such earlier date, the “Share Delivery Date”), the
Company shall (X) provided that the Transfer Agent is participating in The Depository Trust Company
(“DTC”) Fast Automated Securities Transfer Program, credit such aggregate number of Warrant Shares to
which the Holder is entitled pursuant to such exercise to the Holder’s or its designee’s balance account with DTC
through its Deposit / Withdrawal At Custodian system, or (Y) if the Transfer Agent is not participating in the DTC Fast
Automated Securities Transfer Program, issue and dispatch by overnight courier to the address as specified in the Exercise
Notice, a certificate, registered in the name of the Holder or its designee, for the number of Warrant Shares to which the
Holder is entitled pursuant to such exercise.  The Company shall be responsible for all fees and expenses of the
Transfer Agent and all fees and expenses with respect to the issuance of Warrant Shares via DTC, if any, including without
limitation for same day processing.  Upon delivery of the Exercise Notice, the Holder shall be deemed for all corporate
purposes to have become the holder of record and beneficial owner of the Warrant Shares with respect to which this Warrant
has been exercised, irrespective of the date such Warrant Shares are credited to the Holder’s DTC account or the date
of delivery of the certificates evidencing such Warrant Shares, as the case may be, provided that the Holder delivers the
Aggregate Exercise Price (or notice of a Cashless Exercise) within one (1) Trading Day of delivery of the Exercise
Notice.  If this Warrant is physically delivered to the Company in connection with any exercise pursuant to this
Section 1(a) and the number of Warrant Shares represented by this Warrant submitted for exercise is greater than
the number of Warrant Shares being acquired upon an exercise, then the Company shall as soon as practicable and in no event
later than five (5) Trading Days after any exercise and at its own expense, issue and deliver to the Holder (or its
designee) a new Warrant (in accordance with Section 7(d)) representing the right to purchase the number of Warrant
Shares issuable immediately prior to such exercise under this Warrant, less the number of Warrant Shares with respect to
which this Warrant is exercised.  No fractional Warrant Shares are to be issued upon the exercise of this Warrant, but
rather the number of Warrant Shares to be issued shall be rounded to the nearest whole number.  The Company shall pay
any and all transfer, stamp, issuance and similar taxes, costs and expenses (including, without limitation, fees and expenses
of the Transfer Agent) which may be payable with respect to the issuance and delivery of Warrant Shares upon exercise of this
Warrant, provided,  however, that the Company shall not be required to pay any tax which may be
payable based on the income of the Holder or in respect of any transfer involved in the registration of any certificates for
Warrant Shares or Warrants in a name other than that of the Holder or an affiliate thereof. The Holder shall be responsible
for any tax which may be payable based on the income of the Holder or in respect of any transfer involved in the registration
of any certificate for Warrant Shares or Warrants in a name other than that of the Holder or an affiliate
thereof.  The Company’s obligations to issue and deliver Warrant Shares in accordance with the terms and
subject to the conditions hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to
enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person
or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination; provided,
  however, that the Company shall not be required to deliver Warrant Shares with respect to an exercise prior to
the Holder’s delivery of the Aggregate Exercise Price (or notice of a Cashless Exercise) with respect to such
exercise.

 

(b) Exercise
Price.  For purposes of this Warrant, “Exercise Price” means $1.05 per share, subject to adjustment
as provided herein.

 

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(c) Company’s
Failure to Timely Deliver Securities. If either (I) the Company shall fail for any reason or for no reason to issue
to the Holder on or prior to the applicable Share Delivery Date, if (x) the Transfer Agent is not participating in the DTC
Fast Automated Securities Transfer Program, a certificate for the number of shares of Common Stock to which the Holder is
entitled and register such Common Stock on the Company's share register or (y) the Transfer Agent is participating in the DTC
Fast Automated Securities Transfer Program, to credit the Holder's balance account with DTC, for such number of shares of
Common Stock to which the Holder is entitled upon the Holder's exercise of this Warrant or (II) a registration statement
(which may be the Registration Statement) covering the issuance or resale of the Warrant Shares that are the subject of the
Exercise Notice (the "Exercise Notice Warrant Shares") is not available for the issuance or resale, as
applicable, of such Exercise Notice Warrant Shares and (x) the Company fails to promptly, but in no event later than one (1)
Business Day after such registration statement becomes unavailable, to so notify the Holder and (y) upon a Cashless Exercise
(as defined below) the Company is unable to deliver the Exercise Notice Warrant Shares electronically without any restrictive
legend by crediting such aggregate number of Exercise Notice Warrant Shares to the Holder’s or its designee’s
balance account with DTC through its Deposit / Withdrawal At Custodian system (the event described in the immediately
foregoing clause (II) is hereinafter referred as a "Notice Failure" and together with the event described in
clause (I) above, an "Exercise Failure"), then, in addition to all other remedies available to the Holder,
if on or prior to the applicable Share Delivery Date either (I) if the Transfer Agent is not participating in the DTC Fast
Automated Securities Transfer Program, the Company shall fail to issue and deliver a certificate to the Holder and register
such shares of Common Stock on the Company's share register or, if the Transfer Agent is participating in the DTC Fast
Automated Securities Transfer Program, credit the Holder's balance account with DTC for the number of shares of Common Stock
to which the Holder is entitled upon the Holder's exercise hereunder or pursuant to the Company's obligation pursuant to
clause (ii) below or (II) if a Notice Failure occurs, and if after such date the Holder is required by its broker to purchase
(in an open market transaction or otherwise) or the Holder’s brokerage firm otherwise purchases, shares of Common Stock
to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such
exercise (a “Buy-In”), then the Company shall, within three (3) Trading Days after the Holder’s
request (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including
brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1)
the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue
times (2) the price at which the sell order giving rise to such purchase obligation was executed, and (B) at the option of
the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was
not honored (in which case such exercise shall be deemed rescinded) or deliver to the Holder the number of shares of Common
Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For
example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an
attempted exercise of shares of Common Stock with an aggregate sale price giving rise to such purchase obligation of $10,000,
under clause (A) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder
shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy-In and, upon
request of the Company, evidence of the amount of such loss. Nothing herein shall limit a Holder’s right to pursue any
other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance
and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon exercise
of the Warrant as required pursuant to the terms hereof. The Company’s current transfer agent participates in the DTC
Fast Automated Securities Transfer Program (“FAST”). In the event that the Company changes transfer agents
while this Warrant is outstanding, the Company shall select a transfer agent that participates in FAST. While this Warrant is
outstanding, the Company shall cause its transfer agent to participate in FAST with respect to this Warrant. In addition to
the foregoing rights, (i) if the Company fails to deliver the applicable number of Warrant Shares upon an exercise pursuant
to Section 1 by the applicable Share Delivery Date, then the Holder shall have the right to rescind such exercise in whole or
in part and retain and/or have the Company return, as the case may be, any portion of this Warrant that has not been
exercised pursuant to such Exercise Notice; provided that the rescission of an exercise shall not affect the Company’s
obligation to make any payments that have accrued prior to the date of such notice pursuant to this Section 1(c) or
otherwise, and (ii) if a registration statement (which may be the Registration Statement) covering the issuance or resale of
the Warrant Shares that are subject to an Exercise Notice is not available for the issuance or resale, as applicable, of such
Exercise Notice Warrant Shares and the Holder has submitted an Exercise Notice prior to receiving notice of the
non-availability of such registration statement and the Company has not already delivered the Warrant Shares underlying such
Exercise Notice electronically without any restrictive legend by crediting such aggregate number of Warrant Shares to which
the Holder is entitled pursuant to such exercise to the Holder’s or its designee’s balance account with DTC
through its Deposit / Withdrawal At Custodian system, the Holder shall have the option, by delivery of notice to the Company,
to (x) rescind such Exercise Notice in whole or in part and retain or have returned, as the case may be, any portion of this
Warrant that has not been exercised pursuant to such Exercise Notice; provided that the rescission of an Exercise Notice
shall not affect the Company’s obligation to make any payments that have accrued prior to the date of such notice
pursuant to this Section 1(c) or otherwise, and/or (y) switch some or all of such Exercise Notice from a cash exercise to a
Cashless Exercise. In addition to the foregoing, if the Company fails for any reason to deliver to the Holder the Warrant
Shares subject to an Exercise Notice by the second Trading Day following the Share Delivery Date, the Company shall pay to
the Holder, in cash, as liquidated damages and not as a penalty, for each $1,000 of Warrant Shares subject to such exercise
(based on the Weighted Average Price of the Common Stock on the date of the applicable Exercise Notice), $10 per Trading Day
(increasing to $20 per Trading Day on the fifth Trading Day after such liquidated damages begin to accrue) for each Trading
Day after the second Trading Day following such Share Delivery Date until such Warrant Shares are delivered or Holder
rescinds such exercise. In addition to any other rights available to the Holder, if the Company
fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares in accordance with the provisions of
Section 1(a) above pursuant to an exercise on or before the Share Delivery Date, and if after such date the Holder
is required by its broker to purchase (in an open market transaction or otherwise) or the Holder’s brokerage firm
otherwise purchases, shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares
which the Holder anticipated receiving upon such exercise (a “Buy-In”), then the Company shall
(A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including
brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by
multiplying (1) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with
the exercise at issue times (2) the price at which the sell order giving rise to such purchase obligation was executed,
and (B) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares
for which such exercise was not honored (in which case such exercise shall be deemed rescinded) or deliver to the Holder the
number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery
obligations hereunder.  For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to
cover a Buy-In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price giving rise to
such purchase obligation of $10,000, under clause (A) of the immediately preceding sentence the Company shall be
required to pay the Holder $1,000.

 

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(d) Cashless
Exercise.  Notwithstanding anything contained herein to the contrary, the Holder may, in its sole discretion, exercise
this Warrant in whole or in part and, in lieu of making the cash payment otherwise contemplated to be made to the Company upon
such exercise in payment of the Aggregate Exercise Price, elect instead to receive upon such exercise the “Net Number”
of shares of Common Stock determined according to the following formula (a “Cashless Exercise”):

 

Net Number = (A x B)
- (A x C)

 B

 

For purposes of the foregoing formula:

 

A=  the
total number of shares with respect to which this Warrant is then being exercised.

 

B= as
applicable: (i) the Closing Sale Price of the Common Stock on the Trading Day immediately preceding the date of the applicable
Exercise Notice if such Exercise Notice is (1) both executed and delivered pursuant to Section 1(a) hereof on a day that is not
a Trading Day or (2) both executed and delivered pursuant to Section 1(a) hereof on a Trading Day prior to the opening of “regular
trading hours” (as defined in Rule 600(b)(68) of Regulation NMS promulgated under the federal securities laws) on such Trading
Day, (ii) at the option of the Holder, either (y) the Weighted Average Price on the Trading Day immediately preceding the date
of the applicable Notice of Exercise or (z) the Bid Price of the Common Stock as of the time of the Holder’s execution of
the applicable Exercise Notice if such Exercise Notice is executed during “regular trading hours” on a Trading Day
and is delivered within two (2) hours thereafter (including until two (2) hours after the close of “regular trading hours”
on a Trading Day) pursuant to Section 1(a) hereof or (iii) the Closing Sale Price of the Common Stock on the date of the applicable
Exercise Notice if the date of such Exercise Notice is a Trading Day and such Exercise Notice is both executed and delivered pursuant
to Section 1(a) hereof after the close of “regular trading hours” on such Trading Day.

 

C= the
Exercise Price then in effect for the applicable Warrant Shares at the time of such exercise.

 

If Warrant Shares are
issued in such a cashless exercise, the Company acknowledges and agrees that in accordance with Section 3(a)(9) of the Securities
Act of 1933, as amended, the Warrant Shares shall take on the registered characteristics of the Warrant, and the holding period
of the Warrant may be tacked on to the holding period of the Warrant Shares.  The Company agrees not to take any position
contrary to this Section 1(d). Without limiting the rights of a Holder to receive Warrant Shares on a “cashless exercise,”
and to receive the cash payments contemplated pursuant to Sections 1(c) and 4(b), in no event will the Company be required to net
cash settle a Warrant exercise.

 

(e) Disputes. 
In the case of a dispute as to the determination of the Exercise Price or the arithmetic calculation of the Warrant Shares, the
Company shall promptly issue to the Holder the number of Warrant Shares that are not disputed and resolve such dispute in accordance
with Section 11.

 

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(f) Beneficial
Ownership.  Notwithstanding anything to the contrary contained herein, the Company shall not effect the exercise of
any portion of this Warrant, and the Holder shall not have the right to exercise any portion of this Warrant, pursuant to the
terms and conditions of this Warrant and any such exercise shall be null and void and treated as if never made, to the extent
that after giving effect to such exercise, the Holder together with the other Attribution Parties collectively would
beneficially own in excess of 4.99% (the “Maximum Percentage”) of the number of shares of Common Stock
outstanding immediately after giving effect to such exercise.  For purposes of the foregoing sentence, the aggregate
number of shares of Common Stock beneficially owned by the Holder and the other Attribution Parties shall include the number
of shares of Common Stock held by the Holder and all other Attribution Parties plus the number of shares of Common Stock
issuable upon exercise of this Warrant with respect to which the determination of such sentence is being made, but shall
exclude the number of shares of Common Stock which would be issuable upon (A) exercise of the remaining, unexercised
portion of this Warrant beneficially owned by the Holder or any of the other Attribution Parties and (B) exercise or
conversion of the unexercised or unconverted portion of any other securities of the Company (including, without limitation,
any convertible notes or convertible preferred stock or warrants) beneficially owned by the Holder or any other Attribution
Party subject to a limitation on conversion or exercise analogous to the limitation contained in this
Section 1(f).  For purposes of this Section 1(f), beneficial ownership shall be calculated in accordance with
Section 13(d) of the Securities Exchange Act of 1934, as amended (the “1934 Act”), it being
acknowledged that the Company is not representing to the Holder that such calculation is in compliance with
Section 13(d) of the 1934 Act, and the Holder is solely responsible for any schedules required to be filed in
accordance therewith.  For purposes of this Warrant, in determining the number of outstanding shares of Common Stock the
Holder may acquire upon the exercise of this Warrant without exceeding the Maximum Percentage, the Holder may rely on the
number of outstanding shares of Common Stock as reflected in (x) the Company’s most recent Annual Report on
Form 10-K, Quarterly Report on Form 10-Q and Current Reports on Form 8-K or other public filing with the
Securities and Exchange Commission (the “SEC”), as the case may be, (y) a more recent public
announcement by the Company or (3) any other written notice by the Company or the Transfer Agent setting forth the
number of shares of Common Stock outstanding (the “Reported Outstanding Share Number”).  For any
reason at any time, upon the written or oral request of the Holder, where such request indicates that it is being made
pursuant to this Warrant, the Company shall within one (1) Trading Day confirm orally and in writing or by electronic
mail to the Holder the number of shares of Common Stock then outstanding.  In any case, the number of outstanding shares
of Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including
this Warrant, by the Holder and any other Attribution Party since the date as of which the Reported Outstanding Share Number
was reported.  In the event that the issuance of Common Stock to the Holder upon exercise of this Warrant results in the
Holder and the other Attribution Parties being deemed to beneficially own, in the aggregate, more than the Maximum Percentage
of the number of outstanding shares of Common Stock (as determined under Section 13(d) of the 1934 Act), upon
written notice by the Holder to the Company, the number of shares so issued by which the Holder’s and the other
Attribution Parties’ aggregate beneficial ownership exceeds the Maximum Percentage (the “Excess
Shares”) shall be deemed null and void and shall be cancelled ab initio, and the Holder shall not have the power to
vote or to transfer the Excess Shares.  As soon as reasonably practicable after the issuance of the Excess Shares has
been deemed null and void, the Company shall return to the Holder the exercise price paid by the Holder for the Excess
Shares.  Upon delivery of a written notice to the Company, the Holder may from time to time increase or decrease the
Maximum Percentage to any other percentage not in excess of 4.99% as specified in such notice; provided that (i) any
such increase in the Maximum Percentage will not be effective until the sixty-first (61st) day after such notice is delivered
to the Company and (ii) any such increase or decrease will apply only to the Holder and the other Attribution
Parties.  For purposes of clarity, the shares of Common Stock issuable pursuant to the terms of this Warrant in excess
of the Maximum Percentage shall not be deemed to be beneficially owned by the Holder for any purpose including for purposes
of Section 13(d) or Rule 16a-1(a)(1) of the 1934 Act, it being acknowledged that the Company is not
representing to the Holder that such calculation is in compliance with Section 13(d) of the 1934 Act, and the
Holder is solely responsible for any schedules required to be filed in accordance therewith.  No prior inability to
exercise this Warrant pursuant to this paragraph shall have any effect on the applicability of the provisions of this
paragraph with respect to any subsequent determination of exercisability.  The provisions of this paragraph shall be
construed and implemented in a manner otherwise than in strict conformity with the terms of this Section 1(f) to
the extent necessary to correct this paragraph or any portion of this paragraph which may be defective or inconsistent with
the intended beneficial ownership limitation contained in this Section 1(f) or to make changes or supplements
necessary or desirable to properly give effect to such limitation.  The limitation contained in this paragraph may not
be waived and shall apply to a successor holder of this Warrant.

 

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(g) Required
Reserve Amount.  So long as this Warrant remains outstanding, the Company shall at all times keep reserved for issuance
under this Warrant a number of shares of Common Stock at least equal to 100% of the maximum number of shares of Common Stock as
shall be necessary to satisfy the Company’s obligation to issue shares of Common Stock under the Warrant (without regard
to any limitations on exercise) (the “Required Reserve Amount”); provided that at no time shall
the number of shares of Common Stock reserved pursuant to this Section 1(g) be reduced other than in connection with
any exercise of the Warrant, in whole or in part, or such other event covered by Section 2(c) below.

 

(h) Insufficient
Authorized Shares.  If at any time while this Warrant remains outstanding the Company does not have a sufficient number
of authorized and unreserved shares of Common Stock to satisfy its obligation to reserve for issuance the Required Reserve Amount
(an “Authorized Share Failure”), then the Company shall promptly take all action reasonably necessary to increase
the Company’s authorized shares of Common Stock to an amount sufficient to allow the Company to reserve the Required Reserve
Amount for this Warrant then outstanding.  Without limiting the generality of the foregoing sentence, as soon as practicable
after the date of the occurrence of an Authorized Share Failure, but in no event later than ninety (90) days after the occurrence
of such Authorized Share Failure, the Company shall hold a meeting of its stockholders for the approval of an increase in the number
of authorized shares of Common Stock.  In connection with such meeting, the Company shall provide each stockholder with a
proxy statement and shall use its reasonable best efforts to solicit its stockholders’ approval of such increase in authorized
shares of Common Stock and to cause its board of directors to recommend to the stockholders that they approve such proposal. 
Notwithstanding the foregoing, if any such time of an Authorized Share Failure, the Company is able to obtain the written consent
of a majority of the shares of its issued and outstanding shares of Common Stock to approve the increase in the number of authorized
shares of Common Stock, the Company may satisfy this obligation by obtaining such consent and submitting for filing with the SEC
an Information Statement on Schedule 14C.

 

2. ADJUSTMENT
OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES.  The Exercise Price and the number of Warrant Shares shall be adjusted
from time to time as follows:

 

(a) Intentionally
omitted.

 

(b) Intentionally
omitted.

 

(c) Adjustment
Upon Subdivision or Combination of Common Stock.  If the Company at any time on or after the Effective Date subdivides
(by any stock split, stock dividend, recapitalization or otherwise) one or more classes of its outstanding shares of Common Stock
into a greater number of shares, the Exercise Price in effect immediately prior to such subdivision will be proportionately reduced
and the number of Warrant Shares will be proportionately increased.  If the Company at any time on or after the Effective
Date combines (by combination, reverse stock split or otherwise) one or more classes of its outstanding shares of Common Stock
into a smaller number of shares, the Exercise Price in effect immediately prior to such combination will be proportionately increased
and the number of Warrant Shares will be proportionately decreased.  Any adjustment under this Section 2(c) shall
become effective at the close of business on the date the subdivision or combination becomes effective.

 

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3. RIGHTS
UPON DISTRIBUTION OF ASSETS.  In addition to any adjustments pursuant to Section 2 above, if, on or after the
Effective Date and on or prior to the Expiration Date, the Company shall declare or make any dividend or other distribution
of its assets (or rights to acquire its assets) to holders of shares of Common Stock, by way of return of capital or
otherwise (including, without limitation, any distribution of cash, stock or other securities, property, options,
evidence of indebtedness or any other assets by way of a dividend, spin off, reclassification, corporate rearrangement,
scheme of arrangement or other similar transaction) (a “Distribution”), at any time after the issuance of
this Warrant, then, in each such case, the Holder shall be entitled to participate in such Distribution to the same extent
that the Holder would have participated therein if the Holder had held the number of shares of Common Stock acquirable upon
complete exercise of this Warrant (without regard to any limitations or restrictions on exercise of this Warrant, including
without limitation, the Maximum Percentage) immediately before the date on which a record is taken for such Distribution, or,
if no such record is taken, the date as of which the record holders of shares of Common Stock are to be determined for the
participation in such Distribution (provided,  however, that to the extent that the Holder’s right
to participate in any such Distribution would result in the Holder and the other Attribution Parties exceeding the Maximum
Percentage, then the Holder shall not be entitled to participate in such Distribution to such extent (and shall not be
entitled to beneficial ownership of such shares of Common Stock as a result of such Distribution (and beneficial ownership)
to such extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until such time
or times as its right thereto would not result in the Holder and the other Attribution Parties exceeding the Maximum
Percentage, at which time or times the Holder shall be granted such Distribution (and any Distributions declared or made on
such initial Distribution or on any subsequent Distribution held similarly in abeyance) to the same extent as if there had
been no such limitation).

 

4. FUNDAMENTAL
TRANSACTIONS.  The Company shall not enter into or be party to a Fundamental Transaction unless the Successor Entity
assumes in writing all of the obligations of the Company under this Warrant in accordance with the provisions of this Section
4(b), including agreements to deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced
by a written instrument substantially similar in form and substance to this Warrant, including, without limitation, which is
exercisable for a corresponding number of shares of capital stock equivalent to the shares of Common Stock acquirable and
receivable upon exercise of this Warrant (without regard to any limitations on the exercise of this Warrant) prior to such
Fundamental Transaction, and with an exercise price which applies the exercise price hereunder to such shares of capital
stock (but taking into account the relative value of the shares of Common Stock pursuant to such Fundamental Transaction and
the value of such shares of capital stock, such adjustments to the number of shares of capital stock and such exercise price
being for the purpose of protecting the economic value of this Warrant immediately prior to the consummation of such
Fundamental Transaction). Upon the consummation of each Fundamental Transaction, the Successor Entity shall succeed to, and
be substituted for the Company (so that from and after the date of the applicable Fundamental Transaction, the provisions of
this Warrant and the other Transaction Documents referring to the “Company” shall refer instead to the Successor
Entity), and may exercise every right and power of the Company and shall assume all of the obligations of the Company under
this Warrant with the same effect as if such Successor Entity had been named as the Company herein. Upon consummation of each
Fundamental Transaction, the Successor Entity shall deliver to the Holder confirmation that there shall be issued upon
exercise of this Warrant at any time after the consummation of the applicable Fundamental Transaction, in lieu of the shares
of Common Stock (or other securities, cash, assets or other property (except such items still issuable under Sections 3 and
4(a) above, which shall continue to be receivable thereafter)) issuable upon the exercise of this Warrant prior to the
applicable Fundamental Transaction, such shares of common stock (or its equivalent) of the Successor Entity (including its
Parent Entity) which the Holder would have been entitled to receive upon the happening of the applicable Fundamental
Transaction had this Warrant been exercised immediately prior to the applicable Fundamental Transaction (without regard to
any limitations on the exercise of this Warrant), as adjusted in accordance with the provisions of this Warrant.
Notwithstanding the foregoing, and without limiting Section 1(f) hereof, the Holder may elect, at its sole option, by
delivery of written notice to the Company to waive this Section 4(b) to permit the Fundamental Transaction without the
assumption of this Warrant. In addition to and not in substitution for any other rights hereunder, prior to the consummation
of each Fundamental Transaction pursuant to which holders of shares of Common Stock are entitled to receive securities or
other assets with respect to or in exchange for shares of Common Stock (a “Corporate Event”), the Company shall
make appropriate provision to insure that the Holder will thereafter have the right to receive upon an exercise of this
Warrant at any time after the consummation of the applicable Fundamental Transaction but prior to the Expiration Date, in
lieu of the shares of the Common Stock (or other securities, cash, assets or other property (except such items still issuable
under Sections 3 and 4(a) above, which shall continue to be receivable thereafter)) issuable upon the exercise of the Warrant
prior to such Fundamental Transaction, such shares of stock, securities, cash, assets or any other property whatsoever
(including warrants or other purchase or subscription rights) (collectively, the “Corporate Event Consideration”)
which the Holder would have been entitled to receive upon the happening of the applicable Fundamental Transaction had this
Warrant been exercised immediately prior to the applicable Fundamental Transaction (without regard to any limitations on the
exercise of this Warrant). The provision made pursuant to the preceding sentence shall be in a form and substance reasonably
satisfactory to the Holder. The provisions of this Section 4(b) shall apply similarly and equally to successive Fundamental
Transactions and Corporate Events. Notwithstanding the foregoing, in the event of a Change of Control, at the request of the
Holder delivered before the 30th day after such Change of Control, the Company (or the Successor Entity) shall purchase this
Warrant from the Holder by paying to the Holder, within five (5) Business Days after such request (or, if later, on the
effective date of the Change of Control), an amount equal to the Black Scholes Value of the remaining unexercised portion of
this Warrant on the effective date of such Change of Control, payable in cash; provided, however, that, if the Change of
Control is not within the Company's control, including not approved by the Company's Board of Directors, Holder shall only be
entitled to receive from the Company or any Successor Entity, as of the date of consummation of such Change of Control, the
same type or form of consideration (and in the same proportion), at the Black Scholes Value of the unexercised portion of
this Warrant, that is being offered and paid to the holders of Common Stock of the Company in connection with the Change of
Control, whether that consideration be in the form of cash, stock or any combination thereof, or whether the holders of
Common Stock are given the choice to receive from among alternative forms of consideration in connection with the Change of
Control.

 

    -7-

     

    

 

5. NONCIRCUMVENTION. 
The Company hereby covenants and agrees that the Company will not, by amendment of its Certificate of Incorporation or Bylaws,
or through any reorganization, transfer of assets, consolidation, merger, scheme of arrangement, dissolution, issuance 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, and will at all times in good faith carry out all of the provisions of this Warrant and take all action as may be required
to protect the rights of the Holder.  Without limiting the generality of the foregoing, the Company (i) shall not increase
the par value of any shares of Common Stock receivable upon the exercise of this Warrant above the Exercise Price then in effect,
(ii) shall take all such actions as may be necessary or appropriate in order that the Company may validly and legally issue
fully paid and nonassessable shares of Common Stock upon the exercise of this Warrant, and (iii) shall, so long as any portion
of the Warrant remains outstanding, take all action necessary to reserve and keep available out of its authorized and unissued
shares of Common Stock, solely for the purpose of effecting the exercise of the Warrant, the number of shares of Common Stock as
shall from time to time be necessary to effect the exercise of the portion of the Warrant then outstanding (without regard to any
limitations on exercise).

 

6. WARRANT
HOLDER NOT DEEMED A STOCKHOLDER.  Except as otherwise specifically provided herein, the Holder, solely in such
Person’s capacity as a holder of this Warrant, shall not be entitled to vote or receive dividends or be deemed the
holder of capital stock of the Company for any purpose, nor shall anything contained in this Warrant be construed to confer
upon the Holder, solely in such Person’s capacity as the Holder of this Warrant, any of  the rights of a
stockholder of the Company or any right to vote, give or withhold consent to any corporate action (whether any
reorganization, issue of stock, reclassification of stock, consolidation, merger, conveyance or otherwise), receive notice of
meetings, receive dividends or subscription rights, or otherwise, prior to the issuance to the Holder of the Warrant Shares
which such Person is then entitled to receive upon the due exercise of this Warrant.  In addition, nothing contained in
this Warrant shall be construed as imposing any liabilities on the Holder to purchase any securities (upon exercise of this
Warrant or otherwise) or as a stockholder of the Company, whether such liabilities are asserted by the Company or by
creditors of the Company.  Notwithstanding this Section 6, the Company shall provide the Holder with copies of the
same notices and other information given to the stockholders of the Company generally, contemporaneously with the giving
thereof to the stockholders.

 

    -8-

     

    

 

7. REISSUANCE
OF WARRANT.

 

(a) Transfer
of Warrant.  If this Warrant is to be transferred, the Holder shall surrender this Warrant to the Company, whereupon the
Company will forthwith issue and deliver upon the order of the Holder a new Warrant (in accordance with Section 7(d)), registered
as the Holder may request, representing the right to purchase the number of Warrant Shares being transferred by the Holder and,
if less than the total number of Warrant Shares then underlying this Warrant is being transferred, a new Warrant (in accordance
with Section 7(d)) to the Holder representing the right to purchase the number of Warrant Shares not being transferred.

 

(b) Lost, Stolen
or Mutilated Warrant.  Upon receipt by the Company of evidence reasonably satisfactory to the Company of the loss, theft,
destruction or mutilation of this Warrant, and, in the case of loss, theft or destruction, of any indemnification undertaking by
the Holder to the Company in customary form (but without the obligation to post a bond) and, in the case of mutilation, upon surrender
and cancellation of this Warrant, the Company shall execute and deliver to the Holder a new Warrant (in accordance with Section 7(d))
representing the right to purchase the Warrant Shares then underlying this Warrant.

 

(c) Exchangeable
for Multiple Warrants.  This Warrant is exchangeable, upon the surrender hereof by the Holder at the principal office
of the Company, for a new Warrant or Warrants (in accordance with Section 7(d)) representing in the aggregate the right to
purchase the number of Warrant Shares then underlying this Warrant, and each such new Warrant will represent the right to purchase
such portion of such Warrant Shares as is designated by the Holder at the time of such surrender, provided, however, that the Company
shall not be required to issue Warrants for fractional shares of Common Stock hereunder.

 

(d) Issuance of New Warrants. 
Whenever the Company is required to issue a new Warrant pursuant to the terms of this Warrant, such new Warrant (i) shall
be of like tenor with this Warrant, (ii) shall represent, as indicated on the face of such new Warrant, the right to
purchase the Warrant Shares then underlying this Warrant (or in the case of a new Warrant being issued pursuant to Section 7(a) or
Section 7(c), the Warrant Shares designated by the Holder which, when added to the number of shares of Common Stock underlying
the other new Warrants issued in connection with such issuance, does not exceed the number of Warrant Shares then underlying this
Warrant), (iii) shall have an issuance date, as indicated on the face of such new Warrant which is the same as the Issuance
Date, and (iv) shall have the same rights and conditions as this Warrant.

 

    -9-

     

    

 

8. NOTICES. 
Whenever notice is required to be given under this Warrant, including, without limitation, an Exercise Notice, unless
otherwise provided herein, such notice shall be given in writing, (i) if delivered (a) from within the domestic
United States, by first-class registered or certified airmail, or nationally recognized overnight express courier, postage
prepaid, electronic mail or by facsimile or (b) from outside the United States, by International Federal Express,
electronic mail or facsimile, and (ii) will be deemed given (A) if delivered by first-class registered or certified
mail domestic, three (3) Trading Days after so mailed, (B) if delivered by nationally recognized overnight carrier,
one (1) Trading Day after so mailed, (C) if delivered by International Federal Express, two  (2) Trading
Days after so mailed and (D) on the date of transmission, if delivered by electronic mail to each of the email addresses
specified in this Section 8 prior to 5:00 p.m. (New York time) on a Trading Day, and (E) the next Trading Day
after the date of transmission, if delivered by electronic mail to each of the email addresses specified in this
Section 8 on a day that is not a Trading Day or later than 5:00 p.m. (New York time) on any Trading Day, and will
be delivered and addressed as follows:

 

(i) if to the Company, to:

Moleculin Biotech, Inc.

5300 Memorial Drive, Suite 950

Houston, TX 77007

Telephone: (713) 300-5160

Attention: Jonathan P. Foster, Chief Financial
Officer

Email: jfoster@moleculin.com

 

(ii) if to the Holder,
at such address or other contact information delivered by the Holder to Company or as is on the books and records of the Company.

 

The Company shall provide the Holder with
prompt written notice of all actions taken pursuant to this Warrant, including in reasonable detail a description of such action
and the reason therefor.  Without limiting the generality of the foregoing, the Company will give written notice to the Holder
(i) reasonably promptly upon any adjustment of the Exercise Price, setting forth in reasonable detail, and certifying, the
calculation of such adjustment and (ii) at least ten (10) days prior to the date on which the Company closes its books
or takes a record (A) with respect to any dividend or distribution upon the shares of Common Stock, (B) with respect
to any grants, issuances or sales of any Options, Convertible Securities or rights to purchase stock, warrants, securities or other
property pro rata to holders of any class of shares of Common Stock or (C) for determining rights to vote with respect to
any Fundamental Transaction, dissolution or liquidation; provided in each case that such information shall be
made known to the public prior to or in conjunction with such notice being provided to the Holder.  It is expressly understood
and agreed that the time of exercise specified by the Holder in each Exercise Notice shall be definitive and may not be disputed
or challenged by the Company.

 

9. AMENDMENT
AND WAIVER.  Except as otherwise provided herein, the provisions of this Warrant may be amended or waived and the Company
may take any action herein prohibited, or omit to perform any act herein required to be performed by it, only if the Company has
obtained the written consent of the Holder.

 

    -10-

     

    

 

10. GOVERNING
LAW; JURISDICTION; JURY TRIAL.  This Warrant shall be governed by and construed and enforced in accordance with, and
all questions concerning the construction, validity, interpretation and performance of this Warrant shall be governed by, the
internal laws of the State of New York, without giving effect to any choice of law or conflict of law provision or
rule (whether of the State of New York or any other jurisdictions) that would cause the application of the laws of any
jurisdictions other than the State of New York. The Company 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, any claim that it is not personally subject to the jurisdiction of
any such court, that such suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit,
action or proceeding is improper.  The Company 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 to the Company at the address set forth
in Section 8(i) above or such other address as the Company subsequently delivers to the Holder 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.  Nothing contained herein shall be deemed
or operate to preclude the Holder from bringing suit or taking other legal action against the Company in any other
jurisdiction to collect on the Company’s obligations to the Holder, to realize on any collateral or any other security
for such obligations, or to enforce a judgment or other court ruling in favor of the Holder.  If either party shall
commence an action, suit or proceeding to enforce any provisions of this Warrant, the prevailing party in such action, suit
or proceeding shall be reimbursed by the other party for their reasonable attorneys’ fees and other costs and expenses
incurred with the investigation, preparation and prosecution of such action or proceeding.   THE COMPANY HEREBY
IRREVOCABLY WAIVES ANY RIGHT IT MAY HAVE, AND AGREES NOT TO REQUEST, A JURY TRIAL FOR THE ADJUDICATION OF ANY DISPUTE
HEREUNDER OR IN CONNECTION WITH OR ARISING OUT OF THIS WARRANT OR ANY TRANSACTION CONTEMPLATED HEREBY.

 

11. DISPUTE RESOLUTION. 
In the case of a dispute as to the determination of the Exercise Price or the arithmetic calculation of the Warrant Shares, the
Company shall submit the disputed determinations or arithmetic calculations via facsimile or electronic mail within two (2) Trading
Days of receipt of the Exercise Notice or other event giving rise to such dispute, as the case may be, to the Holder.  If
the Holder and the Company are unable to agree upon such determination or calculation of the Exercise Price or the Warrant Shares
within five (5) Trading Days of such disputed determination or arithmetic calculation being submitted to the Holder, then
the Company shall, within two (2) Trading Days submit via facsimile or electronic mail (a) the disputed determination
of the Exercise Price to an independent, reputable investment bank selected by the Company and approved by the Holder  or
(b) the disputed arithmetic calculation of the Warrant Shares to the Company’s independent, outside accountant. 
The Company shall cause the investment bank or the accountant, as the case may be, to perform the determinations or calculations
and notify the Company and the Holder of the results no later than ten (10) Trading Days from the time it receives the disputed
determinations or calculations.  Such investment bank’s or accountant’s determination or calculation, as the case
may be, shall be binding upon all parties absent demonstrable error. The expenses of the investment bank and accountant will be
borne by the Company unless the investment bank or accountant determines that the determination of the Exercise Price or the arithmetic
calculation of the Warrant Shares by the Company was correct, in which case the expenses of the investment bank and accountant
will be borne by the Holder.

 

12. REMEDIES,
OTHER OBLIGATIONS, BREACHES AND INJUNCTIVE RELIEF.  The remedies provided in this Warrant shall be cumulative and in
addition to all other remedies available under this Warrant, at law or in equity (including a decree of specific performance
and/or other injunctive relief), 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 this Warrant.  The Company acknowledges that a breach by it of its
obligations hereunder will cause irreparable harm to the Holder and that the remedy at law for any such breach may be
inadequate.  The Company therefore agrees that, in the event of any such breach or threatened breach, the holder of this
Warrant shall be entitled, in addition to all other available remedies, to seek an injunction restraining any breach, without
the necessity of showing economic loss and without any bond or other security being required. Notwithstanding the foregoing
or anything else herein to the contrary, but without limiting the Holder’s rights to cashless exercise under Section
1(d) or the right to cash payments pursuant to Section 1(c) if the Company is for any reason unable to issue and deliver
Warrant Shares upon exercise of this Warrant as required pursuant to the terms hereof, the Company shall have no obligation
to pay to the Holder any cash or other consideration or otherwise “net cash settle” this Warrant.

 

    -11-

     

    

 

13. TRANSFER. 
Subject to applicable laws and restrictions set forth in this paragraph, this Warrant may be offered for sale, sold, transferred
or assigned without the consent of the Company.  The Holder agrees that, pursuant to the Lock-Up Period (as defined below)
contained in Rule 5110(g)(1) of the Financial Industry Regulatory Authority, Inc. (“FINRA”), it will
not (a) sell, transfer, assign, pledge, hypothecate or otherwise transfer this Warrant (including any Warrant Shares issued
or issuable hereunder) other than to a bona fide officer or partner of the Holder or any selected dealer in connection with the
offering contemplated by the Placement Agent Agreement, in each case in accordance with FINRA Conduct Rule 5110(g)(1), or
(b) cause this Warrant or any Warrant Shares issued or issuable hereunder to be the subject of any hedging, short sale, derivative,
put or call transaction that would result in the effective economic disposition of this Warrant or any Warrant Shares issued or
issuable hereunder, except as provided for in FINRA Rule 5110(g)(2).  As used herein, the term “Lock-Up Period”
means the period beginning on the Effective Date and ending on the one hundred eightieth day anniversary of the Effective Date.

 

14. SEVERABILITY;
CONSTRUCTION; HEADINGS.  If any provision of this Warrant is prohibited by law or otherwise determined to be invalid or
unenforceable by a court of competent jurisdiction, the provision that would otherwise be prohibited, invalid or unenforceable
shall be deemed amended to apply to the broadest extent that it would be valid and enforceable, and the invalidity or unenforceability
of such provision shall not affect the validity of the remaining provisions of this Warrant so long as this Warrant as so modified
continues to express, without material change, the original intentions of the parties as to the subject matter hereof and the prohibited
nature, invalidity or unenforceability of the provision(s) in question does not substantially impair the respective expectations
or reciprocal obligations of the parties or the practical realization of the benefits that would otherwise be conferred upon the
parties.  The parties will endeavor in good faith negotiations to replace the prohibited, invalid or unenforceable provision(s) with
a valid provision(s), the effect of which comes as close as possible to that of the prohibited, invalid or unenforceable provision(s). 
This Warrant shall be deemed to be jointly drafted by the Company and the Holder and shall not be construed against any Person
as the drafter hereof.  The headings of this Warrant are for convenience of reference and shall not form part of, or affect
the interpretation of, this Warrant.

 

15. DISCLOSURE. 
Upon receipt or delivery by the Company of any notice in accordance with the terms of this Warrant, unless the Company has in good
faith determined that the matters relating to such notice do not constitute material, nonpublic information relating to the Company
or its subsidiaries, the Company shall contemporaneously with any such receipt or delivery publicly disclose such material, nonpublic
information on a Current Report on Form 8-K or otherwise.  In the event that the Company believes that a notice contains
material, nonpublic information relating to the Company or its subsidiaries, the Company so shall indicate to such Holder contemporaneously
with delivery of such notice, and in the absence of any such indication, the Holder shall be allowed to presume that all matters
relating to such notice do not constitute material, nonpublic information relating to the Company or its subsidiaries.

 

    -12-

     

    

 

16. CERTAIN DEFINITIONS. 
For purposes of this Warrant, the following terms shall have the following meanings:

 

(a) “Affiliate”
means, with respect to any Person, any other Person that directly or indirectly controls, is controlled by, or is under
common control with, such Person, it being understood for purposes of this definition that “control” of a Person
means the power directly or indirectly either to vote 10% or more of the stock having ordinary voting power for the election
of directors of such Person or direct or cause the direction of the management and policies of such Person whether by
contract or otherwise.

 

(b) “Attribution
Parties” means, collectively, the following Persons and entities: (i) any investment vehicle, including, any funds,
feeder funds or managed accounts, currently, or from time to time after the Effective Date, directly or indirectly managed or advised
by the Holder’s investment manager or any of its Affiliates or principals, (ii) any direct or indirect Affiliates of
the Holder or any of the foregoing, (iii) any Person acting or who could be deemed to be acting as a Group together with the
Holder or any of the foregoing and (iv) any other Persons whose beneficial ownership of the Company’s Common Stock would
or could be aggregated with the Holder’s and the other Attribution Parties for purposes of Section 13(d) of the
1934 Act.  For clarity, the purpose of the foregoing is to subject collectively the Holder and all other Attribution Parties
to the Maximum Percentage.

 

(c) Bid Price”  means,
for any security as of the particular time of determination, the bid price for such security on the Principal Market as reported
by Bloomberg as of such time of determination, or, if the Principal Market is not the principal securities exchange or trading
market for such security, the bid price of such security on the principal securities exchange or trading market where such security
is listed or traded as reported by Bloomberg as of such time of determination, or if the foregoing does not apply, the bid price
of such security in the over-the-counter market on the electronic bulletin board for such security as reported by Bloomberg as
of such time of determination, or, if no bid price is reported for such security by Bloomberg as of such time of determination,
the average of the bid prices of any market makers for such security as reported on the Pink Open Market (formerly Pink OTC Markets
Inc.) as of such time of determination.  If the Bid Price cannot be calculated for a security as of the particular time
of determination on any of the foregoing bases, the Bid Price of such security as of such time of determination shall be the fair
market value as mutually determined by the Company and the Holder.  If the Company and the Holder are unable to agree
upon the fair market value of such security, then such dispute shall be resolved in accordance with the procedures in Section 11.
All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination or other similar
transaction during such period. 

 

(d) “Black
Scholes Value” means the value of this Warrant based on the Black-Scholes Option Pricing Model obtained from the "OV"
function on Bloomberg determined as of the day immediately following the first public announcement of the applicable Change of
Control, or, if the Change of Control is not publicly announced, the date the Change of Control is consummated, for pricing purposes
and reflecting (i) a risk-free interest rate corresponding to the U.S. Treasury rate for a period equal to the remaining term of
this Warrant as of such date of request, (ii) an expected volatility equal to 100% (iii) the underlying price per share used in
such calculation shall be the greater of (a) the highest Weighted Average Price during the five (5) Trading Days prior to the closing
of the Change of Control and (b) the sum of the price per share being offered in cash, if any, plus the value of any non-cash consideration,
if any, being offered in such Change of Control, (iv) a zero cost of borrow and (v) a 360 day annualization factor.

 

(e) “Bloomberg”
means Bloomberg Financial Markets.

 

(f) “Business
Day” means any day other than Saturday, Sunday or other day on which commercial banks in The City of New York are authorized
or required by law to remain closed.

 

    -13-

     

    

 

(g)
 “Change of Control” means any Fundamental Transaction other than (i) any reorganization, recapitalization
or reclassification of the Common Stock in which holders of the Company’s voting power immediately prior to such
reorganization, recapitalization or reclassification continue after such reorganization, recapitalization or reclassification
to hold publicly traded securities and, directly or indirectly, are, in all material respect, the holders of the voting power
of the surviving entity (or entities with the authority or voting power to elect the members of the board of directors (or
their equivalent if other than a corporation) of such entity or entities) after such reorganization, recapitalization or
reclassification, (ii) pursuant to a migratory merger effected solely for the purpose of changing the jurisdiction of
incorporation of the Company or (iii) a merger in connection with a bona fide acquisition by the Company of any Person in
which (x) the gross consideration paid, directly or indirectly, by the Company in such acquisition is not greater than 20% of
the Company’s market capitalization as calculated on the date of the consummation of such merger and (y) such merger
does not contemplate a change to the identity of a majority of the board of directors of the Company. Notwithstanding
anything herein to the contrary, any transaction or series of transaction that, directly or indirectly, results in the
Company or the Successor Entity not having Common Stock or common stock, as applicable, registered under the 1934 Act and
listed on an Eligible Market shall be deemed a Change of Control.

 

(h) “Closing
Sale Price” means, for any security as of any date, the last closing trade price for such security on the Principal
Market, as reported by Bloomberg, or, if the Principal Market begins to operate on an extended hours basis and does not designate
the closing trade price then the last trade price of such security prior to 4:00:00 p.m., New York time, as reported by Bloomberg,
or, if the Principal Market is not the principal securities exchange or trading market for such security, the last trade price of
such security on the principal securities exchange or trading market where such security is listed or traded as reported by Bloomberg,
or if the foregoing do not apply, the last trade price of such security in the over-the-counter market on the electronic bulletin
board for such security as reported by Bloomberg, or, if no last trade price is reported for such security by Bloomberg, the average
of the ask prices of any market makers for such security as reported on the Pink Open Market (formerly Pink OTC Markets Inc.).  If
the Closing Sale Price cannot be calculated for a security on a particular date on any of the foregoing bases, the Closing Sale
Price of such security on such date shall be the fair market value as mutually determined by the Company and the Holder.  If
the Company and the Holder are unable to agree upon the fair market value of such security, then such dispute shall be resolved
pursuant to Section 11.  All such determinations to be appropriately adjusted for any stock dividend, stock split, stock
combination, reclassification or other similar transaction during the applicable calculation period.

  

(i) “Common
Stock” means (i) the Company’s Common Stock, par value $0.001 per share, and (ii) any capital stock into
which such Common Stock shall have been changed or any capital stock resulting from a reclassification of such Common Stock.

 

(j) “Convertible
Securities” means any stock or securities (other than Options) directly or indirectly convertible into or exercisable
or exchangeable for shares of Common Stock.

 

(k) “Eligible
Market” means The NASDAQ Capital Market, the NYSE American LLC, The NASDAQ Global Select Market, The NASDAQ Global Market
or The New York Stock Exchange, Inc.

 

(l) “Expiration
Date” means the date sixty (60) months after the Initial Exercisability Date or, if such date falls on a day other
than a Trading Day, the next day that is a Trading Day, which date may not be more than five years from the effective date of the
offering pursuant to FINRA Rule 5110(f)(2)(G)(i).

 

    -14-

     

    

 

(m) “Fundamental
Transaction” means (A) that the Company shall, directly or indirectly, including through subsidiaries,
Affiliates or otherwise, in one or more related transactions, (i) consolidate or merge with or into (whether or not the
Company is the surviving corporation) another Subject Entity, or (ii) sell, assign, transfer, convey or otherwise
dispose of all or substantially all of the properties or assets of the Company or any of its “significant
subsidiaries” (as defined in Rule 1-02 of Regulation S-X) to one or more Subject Entities, or (iii) make, or
allow one or more Subject Entities to make, or allow the Company to be subject to or have its shares of Common Stock be
subject to or party to one or more Subject Entities making, a purchase, tender or exchange offer that is accepted by the
holders of at least either (x) 50% of the outstanding shares of Common Stock, (y) 50% of the outstanding shares of
Common Stock calculated as if any shares of Common Stock held by all Subject Entities making or party to, or Affiliated with
any Subject Entities making or party to, such purchase, tender or exchange offer were not outstanding; or (z) such
number of shares of Common Stock such that all Subject Entities making or party to, or Affiliated with any Subject Entity
making or party to, such purchase, tender or exchange offer, become collectively the beneficial owners (as defined in
Rule 13d-3 under the 1934 Act) of at least 50% of the outstanding shares of Common Stock, or (iv) consummate a
stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization,
spin-off or scheme of arrangement) with one or more Subject Entities whereby all such Subject Entities, individually or in
the aggregate, acquire, either (x) at least 50% of the outstanding shares of Common Stock, (y) at least 50% of the
outstanding shares of Common Stock calculated as if any shares of Common Stock held by all the Subject Entities making or
party to, or Affiliated with any Subject Entity making or party to, such stock purchase agreement or other business
combination were not outstanding; or (z) such number of shares of Common Stock such that the Subject Entities become
collectively the beneficial owners (as defined in Rule 13d-3 under the 1934 Act) of at least 50% of the outstanding
shares of Common Stock, or (v) reorganize, recapitalize or reclassify its shares of Common Stock (other than a
reorganization, recapitalization or reclassification subject to Section 2(c)), (B) that the Company shall, directly or
indirectly, including through subsidiaries, Affiliates or otherwise, in one or more related transactions, allow any Subject
Entity individually or the Subject Entities in the aggregate to be or become the “beneficial owner” (as defined
in Rule 13d-3 under the 1934 Act), directly or indirectly, whether through acquisition, purchase, assignment,
conveyance, tender, tender offer, exchange, reduction in outstanding shares of Common Stock, merger, consolidation, business
combination, reorganization, recapitalization, spin-off, scheme of arrangement, reorganization, recapitalization or
reclassification or otherwise in any manner whatsoever, of either (x) at least 50% of the aggregate ordinary voting
power represented by issued and outstanding shares of Common Stock, (y) at least 50% of the aggregate ordinary voting
power represented by issued and outstanding shares of Common Stock not held by all such Subject Entities as of the Effective
Date calculated as if any shares of Common Stock held by all such Subject Entities were not outstanding, or (z) a
percentage of the aggregate ordinary voting power represented by issued and outstanding shares of Common Stock or other
equity securities of the Company sufficient to allow such Subject Entities to effect a statutory short form merger or other
transaction requiring other stockholders of the Company to surrender their Common Stock without approval of the stockholders
of the Company or (C) directly or indirectly, including through subsidiaries, Affiliates or otherwise, in one or more
related transactions, the issuance of or the entering into any other instrument or transaction structured in a manner to
circumvent, or that circumvents, the intent of this definition in which case this definition shall be construed and
implemented in a manner otherwise than in strict conformity with the terms of this definition to the extent necessary to
correct this definition or any portion of this definition which may be defective or inconsistent with the intended treatment
of such instrument or transaction.

 

(n) “Group”
means a “group” as that term is used in Section 13(d) of the 1934 Act and as defined in Rule 13d-5 thereunder.

 

(o) “Options”
means any rights, warrants or options to subscribe for or purchase shares of Common Stock or Convertible Securities.

 

    -15-

     

    

 

(p) “Parent
Entity” of a Person means an entity that, directly or indirectly, controls the applicable Person, including such entity
whose common stock or equivalent equity security is quoted or listed on an Eligible Market (or, if so elected by the Holder, any
other market, exchange or quotation system), or, if there is more than one such Person or such entity, the Person or such entity
designated by the Holder or in the absence of  such designation, such Person or entity with the largest public market
capitalization as of the date of consummation of the Fundamental Transaction.

 

(q) “Person”
means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization,
any other entity and a government or any department or agency thereof.

 

(r) “Principal
Market” means The NASDAQ Capital Market.

 

(s) “Standard
Settlement Period” means the standard settlement period, expressed in a number of Trading Days, for the Company’s
primary trading market or quotation system with respect to the Common Stock that is in effect on the date of receipt
of an applicable Exercise Notice.

 

(t) “Subject
Entity” means any Person, Persons or Group or any Affiliate or associate of any such Person, Persons or Group.

 

(u) “Successor
Entity” means one or more Person or Persons (or, if so elected by the Holder, the Company or Parent Entity) formed by,
resulting from or surviving any Fundamental Transaction or one or more Person or Persons (or, if so elected by the Holder, the
Company or the Parent Entity) with which such Fundamental Transaction shall have been entered into.

 

(v) “Trading
Day” means any day on which the Common Stock is traded on the Principal Market.

 

(w) "Weighted
Average Price" means, for any security as of any date, the dollar volume-weighted average price for such security on the
Principal Market during the period beginning at 9:30:00 a.m., New York time (or such other time as the Principal Market publicly
announces is the official open of trading), and ending at 4:00:00 p.m., New York time (or such other time as the Principal Market
publicly announces is the official close of trading), as reported by Bloomberg through its "Volume at Price" function
or, if the foregoing does not apply, the dollar volume-weighted average price of such security in the over-the-counter market on
the electronic bulletin board for such security during the period beginning at 9:30:00 a.m., New York time (or such other time
as such market publicly announces is the official open of trading), and ending at 4:00:00 p.m., New York time (or such other time
as such market publicly announces is the official close of trading), as reported by Bloomberg, or, if no dollar volume-weighted
average price is reported for such security by Bloomberg for such hours, the average of the highest Closing Bid Price and the lowest
closing ask price of any of the market makers for such security as reported on the Pink Open Market (formerly Pink OTC Markets
Inc.). Weighted Average Price cannot be calculated for a security on a particular date on any of the foregoing bases, the Weighted
Average Price of such security on such date shall be the fair market value as mutually determined by the Company and the Holder.
If the Company and the Holder are unable to agree upon the fair market value of such security, then such dispute shall be resolved
pursuant to Section 11 with the term "Weighted Average Price" being substituted for the term "Exercise Price."
All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination, reclassification
or other similar transaction during the applicable calculation period.

 

[Signature Page Follows]

 

    -16-

     

    

 

IN WITNESS WHEREOF, the
Company has caused this Agent Warrant to Purchase Common Stock to be duly executed as of the Issuance Date set out above.

 

	 	MOLCULIN BIOTECH, INC.
	 
	 	By:	 
	 	Name:	      
	 	Title:	       

 

    -17-

     

    

  

EXHIBIT A

 

EXERCISE NOTICE

 

TO BE EXECUTED BY THE REGISTERED HOLDER
TO EXERCISE THIS

AGENT WARRANT TO PURCHASE COMMON STOCK

 

MOLECULIN BIOTECH, INC.

 

The undersigned holder
hereby exercises the right to purchase                  
shares of Common Stock (“Warrant Shares”) of Moleculin Biotech, Inc., a company organized under the laws of
Delaware (the “Company”), evidenced by the attached Agent Warrant to Purchase Common Stock (the “Warrant”). 
Capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Warrant.

 

1.  Form of
Exercise Price.  The Holder intends that payment of the Exercise Price shall be made as:

 

a “Cash Exercise” with
respect to                   Warrant Shares;
and/or

 

a  “Cashless Exercise” with
respect to                 Warrant Shares.

 

2.  Payment of
Exercise Price.  In the event that the holder has elected a Cash Exercise with respect to some or all of the Warrant Shares
to be issued pursuant hereto, the holder shall pay the Aggregate Exercise Price in the sum of $                   
to the Company in accordance with the terms of the Warrant.

 

3.  Delivery of
Warrant Shares.  The Company shall deliver to the holder            Warrant
Shares in accordance with the terms of the Warrant.

 

4. Representations
and Warranties. By its delivery of this Exercise Notice, the undersigned represents and warrants to the Company that in giving
effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock
(determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended) permitted to be owned
under Section 1(f) of this Warrant to which this notice relates.

 

Date:                
   ,

 

	 	 
	Name of Registered Holder
	 
	 
	By:	 	 
	 	Name:	 
	 	Title:	 

 

    -18-

     

    

 

ACKNOWLEDGMENT

 

The Company hereby
acknowledges this Exercise Notice and hereby directs VStock Transfer, LLC to issue the above indicated number of shares of Common
Stock on or prior to the applicable Share Delivery Date.

 

	 	MOLECULIN BIOTECH, INC.
	 
	 	By:	               
	 	Name:	 
	 	Title:	 
	 

    -19-Exhibit 10.1

 

Moleculin Biotech, Inc.

5300 Memorial Drive, Suite 950

Houston, Texas 77007

 

Ladies and Gentlemen:

 

The undersigned (the “Investor”)
hereby confirms its agreement with Moleculin Biotech, Inc., a Delaware corporation (the “Company”) as follows:

 

1.      
This Subscription Agreement, including the Terms and Conditions For Purchase of
Securities attached hereto as Annex I (collectively, (this “Agreement”) is made as of the date set forth below
between the Company and the Investor.

 

2.       
The Company has authorized the sale and issuance to certain investors of up to
an aggregate of (i) 7,500,000 shares of common stock, par value $0.001 per share (the “Common Stock”), of the
Company (the “Shares”) and (ii) Warrants (the “Warrants”)
to purchase an aggregate of up to 5,625,000 authorized but unissued shares of Common Stock (the “Warrant
Shares”). The Shares, the Warrants and the Warrant Shares are collectively referred to as the “Securities.”
The Shares and Warrants will be offered and sold in a fixed combination consisting of one share of Common Stock and 0.75 of a Warrant.
The Shares and Warrants shall be immediately separable and transferable upon issuance. The form of the Warrant is attached hereto
as Exhibit A.

 

3.      
The offering and sale of the Securities (the “Offering”) are
being made pursuant to (1) an effective Registration Statement on Form S-3, File No. 333-219434 (the “Registration Statement”)
filed by the Company with the Securities and Exchange Commission (the “Commission”) (including the prospectus
contained therein (the “Base Prospectus”), (2) if applicable, certain “free writing prospectuses”
(as that term is defined in Rule 405 under the Securities Act of 1933, as amended (the “Securities Act”)),
that have been or will be filed with the Commission and delivered to the Investor on or prior to the date hereof (the “Issuer
Free Writing Prospectus”), containing certain supplemental information regarding the Securities, the terms of the Offering
and the Company and (3) a Prospectus Supplement (the “Prospectus Supplement” and together with the Base Prospectus,
the “Prospectus”) containing certain supplemental information regarding the Shares and Warrants and terms
of the Offering that has been or will be filed with the Commission and delivered to the Investor (or made available to the
Investor by the filing by the Company of an electronic version thereof with the Commission). 

 

4.      
The Company and the Investor agree that the Investor will purchase from the Company
and the Company will issue and sell to the Investor the Shares and Warrants set forth below for the aggregate Purchase Price set
forth below. The Shares and Warrants shall be purchased pursuant to the Terms and Conditions for Purchase of Securities attached
hereto as Annex I and incorporated herein by this reference as if fully set forth herein. The Investor acknowledges
that the Offering is not being underwritten by the placement agent (the “Placement Agent”) named in the
Prospectus and that there is no minimum offering amount.

 

     

     

    

 

5.      
The manner of settlement of the Shares and Warrants purchased by the Investor shall
be as follows:

 

The Shares shall be settled as follows:

 

Delivery versus
payment (“DVP”) through DTC (i.e., on the Closing Date, the Company shall issue such Shares registered in the
Investor’s name and address as set forth below and released by the Transfer Agent directly to the account(s) at Oppenheimer
 & Co. Inc. (the “Placement Agent”) identified by the Investor; upon receipt of such Shares, the Placement
Agent shall promptly electronically deliver such Shares to the Investor, and simultaneously therewith payment shall be made by
the Placement Agent by wire transfer to the Company). NO LATER THAN ONE (1) BUSINESS DAY AFTER THE EXECUTION OF THIS AGREEMENT
BY THE INVESTOR AND THE COMPANY, THE INVESTOR SHALL:

 

		(I)	NOTIFY THE PLACEMENT AGENT OF THE ACCOUNT OR ACCOUNTS AT THE PLACEMENT
AGENT TO BE CREDITED WITH THE SHARES BEING PURCHASED BY SUCH INVESTOR, AND

 

		(II)	CONFIRM THAT THE ACCOUNT OR ACCOUNTS AT THE PLACEMENT AGENT TO BE
CREDITED WITH THE SHARES BEING PURCHASED BY THE INVESTOR HAVE A MINIMUM BALANCE EQUAL TO THE AGGREGATE PURCHASE PRICE FOR THE SECURITIES
BEING PURCHASED BY THE INVESTOR.

 

IT IS THE INVESTOR’S RESPONSIBILITY
TO (A) MAKE THE NECESSARY WIRE TRANSFER OR CONFIRM THE PROPER ACCOUNT BALANCE IN A TIMELY MANNER AND (B) ARRANGE FOR SETTLEMENT
BY WAY OF DVP IN A TIMELY MANNER. IF THE INVESTOR DOES NOT DELIVER THE AGGREGATE PURCHASE PRICE FOR THE SHARES AND WARRANTS OR
DOES NOT MAKE PROPER ARRANGEMENTS FOR SETTLEMENT IN A TIMELY MANNER, THE SHARES AND WARRANTS MAY NOT BE DELIVERED AT CLOSING TO
THE INVESTOR OR THE INVESTOR MAY BE EXCLUDED FROM THE CLOSING ALTOGETHER.

 

6.      
The executed Warrants shall be delivered to the Investor by mail, registered in
such names and sent to such address as specified by the Investor below.

 

7.      
The Investor represents that, except as set forth below, (a) it has had no position,
office or other material relationship within the past three years with the Company or persons known to it to be affiliates of the
Company, (b) it is not a member of the Financial Industry Regulatory Authority, Inc. (“FINRA”) or a a person
 “assocuated with a member” (as such term is defined under FINRA’s By-laws) as of the Closing, and (c) neither
the Investor nor any group of Investors (as identified in a public filing made with the Commission) of which the Investor is a
part in connection with the Offering, acquired, or obtained the right to acquire, 20% or more of the Common Stock (or securities
convertible into or exercisable for Common Stock) or the voting power of the Company on a post-transaction basis. Exceptions: 

 

     

     

    

 

(If no exceptions, write
 “none.” If left blank, response will be deemed to be “none.”)

 

8.      
The Investor represents that it has received (or otherwise had made available to
it by the filing by the Company of an electronic version thereof with the Commission) the Base Prospectus, dated August 11, 2017,
which is a part of the Company’s Registration Statement, the documents incorporated by reference therein and any free
writing prospectus (collectively, the “Disclosure Package”), prior to or in connection with the receipt
of this Agreement. The Investor acknowledges that, prior to the delivery of this Agreement to the Company, the Investor will receive
certain additional information regarding the Offering, including pricing information (the “Offering Information”).
Such information may be provided to the Investor by any means permitted under the Securities Act, including the Prospectus
Supplement, a free writing prospectus and oral communications.

 

9.      
No offer by the Investor to buy Shares and Warrants will be accepted and no part
of the Purchase Price will be delivered to the Company until the Investor has received the Offering Information and the Company
has accepted such offer by countersigning a copy of this Agreement, and any such offer may be withdrawn or revoked, without obligation
or commitment of any kind, at any time prior to the Company (or the Placement Agent on behalf of the Company) sending (orally,
in writing or by electronic mail) notice of its acceptance of such offer. An indication of interest will involve no obligation
or commitment of any kind until the Investor has been delivered the Offering Information and this Agreement is accepted and
countersigned by or on behalf of the Company.

 

10.   
The Company acknowledges that the only material, non-public information relating
to the Company or its subsidiaries that the Company, its employees or agents has provided to the Investor in connection with the
Offering prior to the date hereof is the existence and terms of the Offering.

 

     

     

    

 

Number of Shares :

 

Number of Warrants:

 

Purchase Price per Share and related Warrant: $0.80

 

Aggregate Purchase Price: $

 

Please confirm that the foregoing correctly
sets forth the agreement between us by signing in the space provided below for that purpose.

 

	 	Dated as of: February 6, 2020
	 	 
	 	INVESTOR

	 	By:	 

	 	Print Name:	 

	 	Title:	 

	 	Address:	 
	 	 

 

     

     

    

 

Agreed and Accepted

this 6th day of February 2020:

 

MOLECULIN BIOTECH, INC.

 

	By:	 	 
	 	Title:	 

 

     

     

    

 

annex
I

 

TERMS AND CONDITIONS FOR PURCHASE OF SECURITIES

 

1.     
Authorization and Sale of the Securities. Subject to the terms and conditions of this Agreement, the Company
has authorized the sale of the Shares and Warrants.

 

2.     
Agreement to Sell and Purchase the Securities; Placement Agent.

 

2.1         
At the Closing (as defined in Section 3.1), the Company will sell to the
Investor, and the Investor will purchase from the Company, upon the terms and conditions set forth herein, the number of Shares
and Warrants set forth on the last page of the Agreement to which these Terms and Conditions for Purchase of Securities are
attached as Annex I (the “Signature Page”) for the aggregate purchase price therefor set forth on
the Signature Page.

 

2.2         
The Company proposes to enter into substantially this same form of Subscription
Agreement with certain other investors (the “Other Investors”) and expects to complete sales of Shares and Warrants
to them. The Investor and the Other Investors are hereinafter sometimes collectively referred to as the “Investors,”
and this Agreement and the Subscription Agreements executed by the Other Investors are hereinafter sometimes collectively
referred to as the “Agreements.”

 

2.3         
Investor acknowledges that the Company has agreed to pay Oppenheimer & Co.
Inc. (the “Placement Agent”) a fee (the “Placement Fee”) and to reimburse the Placement
Agent for certain expenses in respect of the sale of the Shares and Warrants to the Investor.

 

2.4         
The Company has entered into a Placement Agent Agreement, dated the date hereof,
(the “Placement Agreement”), with the Placement Agent that contains representations, warranties, covenants
and agreements of the Company that may be relied upon by the Investor, which shall be a third party beneficiary thereof. The
Company confirms that neither it nor any other Person acting on its behalf has provided the Investor or their agents or counsel
with any information that constitutes or could reasonably be expected to constitute material, nonpublic information, except as
will be disclosed in the Prospectus and/or in the Company’s Form 8-K to be filed with the Commission in connection with the
Offering. The Company understands and confirms that the Investor will rely on the foregoing representations in effecting transactions
in securities of the Company.

 

3.     
Closings and Delivery of the Securities and Funds.

 

3.1          Closing. The
completion of the purchase and sale of the Shares and Warrants (the “Closing”) shall occur at a
place and time (the “Closing Date”) to be specified by the Company and the Placement Agent, and of
which the Investors will be notified in advance by the Placement Agent, in accordance with Rule 15c6-l promulgated under
the Securities Exchange Act of 1934, as amended (the “Exchange Act”). At the Closing, (a) the
Company shall cause the Company’s transfer agent (“Transfer Agent”), to deliver to the Investor the
number of Shares included in the Units set forth on the Signature Page registered in the name of the Investor or, if so
indicated on the Investor Questionnaire attached hereto as Exhibit A, in the name of a nominee designated by the
Investor, (b) the Company shall cause to be delivered to the Investor, a Warrant for the number of Warrant Shares included in
the Units set forth on the Signature Page, and (c) the aggregate purchase price for the Shares and Warrants being purchased
by the Investor will be delivered by or on behalf of the Investor to the Company.

 

     

     

    

 

3.2         
Conditions to the Obligations of the Parties. 

 

3.3   
(a)     Conditions to the Company’s Obligations. The Company’s
obligation to issue and sell the Shares and Warrants to the Investor shall be subject to: (i) the receipt by the Company of
the purchase price for the Shares and Warrants being purchased hereunder as set forth on the Signature Page, and (ii) the
accuracy of the representations and warranties made by the Investor and the fulfillment of those undertakings of the Investor
to be fulfilled prior to the Closing Date.

 

3.4   
(b)    Conditions to the Investor’s Obligations. The Investor’s
obligation to purchase the Shares and Warrants will be subject to (i) the accuracy of the representations and warranties made by
the Company and the fulfillment of those undertakings of the Company to be fulfilled prior to the Closing Date, including without
limitation, those contained in the Placement Agreement and (ii) the delivery of a legal opinion by Schiff Hardin LLP in form and
substance reasonably acceptable to the Investor, and to the condition that the Placement Agent shall not have: (a) terminated
the Placement Agreement pursuant to the terms thereof or (b) determined that the conditions to the closing in the Placement
Agreement have not been satisfied. The Investor’s obligations are expressly not conditioned on the purchase by any or all
of the Other Investors of the Shares and Warrants that they have agreed to purchase from the Company. The Investor understands
and agrees that, in the event that the Placement Agent in its sole discretion determines that the conditions to closing in the
Placement Agreement have not been satisfied or if the Placement Agreement may be terminated for any other reason permitted by such
Placement Agreement, then the Placement Agent may, but shall not be obligated to, terminate such Agreement, which shall have the
effect of terminating this Subscription Agreement pursuant to Section 14 below.

 

3.5         
Delivery of Funds.

 

Payment for the Shares and Warrants shall be made
as follows:

 

Delivery
Versus Payment through The Depository Trust Company. The purchase of the Shares shall be settled by delivery versus payment
through DTC. No later than one (1) business day after the execution of this Agreement by the Investor and the Company,
the Investor shall confirm that the account or accounts at the Placement Agent to be credited with the Shares being purchased by
the Investor have a minimum balance equal to the aggregate purchase price for the Shares and Warrants being purchased by the Investor.

 

3.6         
Delivery of Shares.

 

Delivery
Versus Payment through The Depository Trust Company. No later than one (1) business day after the execution of
this Agreement by the Investor and the Company, the Investor shall notify the Placement Agent of the account or
accounts at the Placement Agent to be credited with the Shares being purchased by such Investor. On the Closing Date, the
Company shall deliver the Shares to the Investor through DTC directly to the account(s) at the Placement Agent identified by
Investor. Upon receipt of such Shares, the Placement Agent shall promptly electronically deliver such Shares to the Investor,
and simultaneously therewith payment shall be made by the Placement Agent by wire transfer to the Company.

 

     

     

    

 

4.     
Representations, Warranties and Covenants of the Investor.

 

The Investor acknowledges,
represents and warrants to, and agrees with, the Company and the Placement Agent that:

 

4.1         
The Investor (a) is knowledgeable, sophisticated and experienced in making, and
is qualified to make decisions with respect to, investments in securities presenting an investment decision like that involved
in the purchase of the Shares and Warrants, including investments in securities issued by the Company and investments in comparable
companies, (b) has answered all questions on the Signature Page and the Investor Questionnaire and the answers thereto are
true and correct as of the date hereof and will be true and correct as of the Closing Date and (c) in connection with its
decision to purchase the Shares and Warrants set forth on the Signature Page, has received and is relying only upon the Disclosure
Package and the documents incorporated by reference therein and the Offering Information.

 

4.2         
 (a) No action has been or will be taken in any jurisdiction outside the United
States by the Company or the Placement Agent that would permit an offering of the Shares and Warrants, or possession or distribution
of offering materials in connection with the issue of the Shares and Warrants in any jurisdiction outside the United States where
action for that purpose is required, (b) if the Investor is outside the United States, it will comply with all applicable
laws and regulations in each foreign jurisdiction in which it purchases, offers, sells or delivers Securities or has in its
possession or distributes any offering material, in all cases at its own expense and (c) the Placement Agent is not authorized
to make and has not made any representation, disclosure or use of any information in connection with the issue, placement, purchase
and sale of the Securities, except as set forth or incorporated by reference in the Registration Statement, Prospectus or any free
writing prospectus.

 

4.3         
(a) The Investor 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 (b) this Agreement constitutes a valid and binding obligation of the Investor enforceable
against the Investor 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 to the enforceability of any rights to indemnification or contribution
that may be violative of the public policy underlying any law, rule or regulation (including any federal or state securities law,
rule or regulation).

 

4.4          The
Investor understands that nothing in this Agreement, the Prospectus, the Disclosure Package, the Offering Information or any
other materials presented to the Investor in connection with the purchase and sale of the Units constitutes legal, tax or
investment advice. The Investor has consulted such legal, tax and investment advisors and made such investigation as it, in
its sole discretion, has deemed necessary or appropriate in connection with its purchase of Shares and Warrants. The Investor
also understands that there is no established public trading market for the Warrants, and that the Company does not expect
such a market to develop. In addition, the Company does not intend to apply for listing of the Warrants on any national
securities exchange or other trading market. The Investor understands that without an active trading market, the liquidity of
the Warrants will be limited.

 

     

     

    

 

4.5         
The Investor will maintain the confidentiality of all information acquired as a
result of the transactions contemplated hereby prior to the public disclosure of that information by the Company in accordance
with Section 13 of this Annex.

 

4.6         
Since the time at which the Placement Agent first provided the material pricing
terms of the Offering, the Investor has not disclosed any material pricing information regarding the Offering to any third parties
(other than its legal, accounting and other advisors) and has not engaged in any purchases or sales of the securities of the Company
(including, without limitation, any Short Sales (as defined herein) involving the Company’s securities). The Investor covenants
that it will not engage in any purchases or sales of the securities of the Company (including Short Sales) prior to the time that
the transactions contemplated by this Agreement are publicly disclosed. The Investor agrees that it will not use any of the Securities
acquired pursuant to this Agreement to cover any short position in the Common Stock if doing so would be in violation of applicable
securities laws. For purposes hereof, “Short Sales” include, without limitation, all “short sales” as defined
in Rule 200 promulgated under Regulation SHO under the Exchange Act, whether or not against the box, and all types of
direct and indirect stock pledges, forward sales contracts, options, puts, calls, short sales, swaps, “put equivalent
positions” (as defined in Rule 16a-1(h) under the Exchange Act) and similar arrangements (including on a total return basis),
and sales and other transactions through non-U.S. broker dealers or foreign regulated brokers.

 

5.      Covenants
of the Company. For a period of 60 days after the date of this Agreement, the Company shall not issue, sell or register
with the Commission (other than (A) a registration on Form S-8 or on any successor form and (B) the filing of one or more
pre-effective amendments to the Company’s registration statement on Form S-3 (Commission File No.: 333-235686)), or
otherwise dispose of, directly or indirectly, any equity securities of the Company (or any securities convertible into,
exercisable for or exchangeable for equity securities of the Company), except for (i) the issuance of the Securities pursuant
to the Registration Statement, (ii) the issuance of the Agent Warrants and the Agent Warrant Shares, (iii) the issuance of
shares of Common Stock upon the exercise or conversion of options or convertible securities outstanding on the date hereof
(provided that such options or convertible securities are not amended or modified after the date hereof to lower the exercise
or conversion price thereof or to increase the number of shares of Common Stock issuable in respect thereof), and (iv) the
issuance of shares pursuant to the Company’s existing stock incentive plan as described in the Registration Statement
and the Prospectus. In the event that during the applicable lock-up period, (A) any shares are issued pursuant to the
Company’s existing stock option plan or bonus plan that are exercisable during the applicable lock-up period or (B) any
registration is effected on Form S-8 or on any successor form relating to shares that are exercisable during such lock-up
period, the Company shall obtain the written agreement of such grantee or purchaser or holder of such registered securities
that, for the applicable lock-up period after the date of this Agreement, such person will not, offer for sale, sell,
distribute, grant any option for the sale of, or otherwise dispose of, directly or indirectly, or exercise any registration
rights with respect to, any shares of Common Stock (or any securities convertible into, exercisable for, or exchangeable for
any shares of Common Stock) owned by such person.

 

     

     

    

 

6.     
Survival of Representations, Warranties and Agreements; Third Party Beneficiary. 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 Investor herein will survive the execution of this Agreement, the delivery to the Investor of the Securities
being purchased and the payment therefor. The Placement Agent shall be a third party beneficiary with respect to the representations,
warranties and agreements of the Investor in Section 4 hereof.

 

7.     
Notices. All notices, requests, consents and other communications hereunder will be in writing, will be mailed
(a) if within the domestic United States by first-class registered or certified airmail, or nationally recognized overnight express
courier, postage prepaid, or by facsimile or (b) if delivered from outside the United States, by International Federal Express
or facsimile, and will be deemed given (i) if delivered by first-class registered or certified mail domestic, three business days
after so mailed, (ii) if delivered by nationally recognized overnight carrier, one business day after so mailed, and (iii) if delivered
by International Federal Express, two business days after so mailed addressed as follows:

 

(a) 
if to the Company, to:

Moleculin Biotech, Inc.

5300 Memorial Drive, Suite 950

Houston, Texas 77007

Attention: Jonathan P. Foster, CFO

with a copy (which shall not constitute notice) to:

Schiff Hardin LLP

100 North 18th Street

Philadelphia, Pennsylvania 19103

Attention: Cavas S. Pavri

 

(b) 
 if to the Investor, at its address on the Signature Page hereto, or at such other address or addresses as may have been
furnished to the Company in writing.

 

8.     
Changes. This Agreement may not be modified or amended except pursuant to an instrument in writing signed
by the Company and the Investor.

 

9.     
Headings. The headings of the various sections of this Agreement have been inserted for convenience of reference
only and will not be deemed to be part of this Agreement.

 

10. 
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 will not in any way be
affected or impaired thereby.

 

     

     

    

 

11. 
Governing Law. This Agreement will be governed by, and construed in accordance with, the internal laws of
the State of New York, without giving effect to the principles of conflicts of law that would require the application of the
laws of any other jurisdiction.

 

12. 
Counterparts. This Agreement may be executed in two or more counterparts, each of which will constitute an original,
but all of which, when taken together, will constitute but one instrument, and will become effective when one or more counterparts
have been signed by each party hereto and delivered to the other parties. The Company and the Investor acknowledge and agree that
the Company shall deliver its counterpart to the Investor along with the Prospectus (or the filing by the Company of an electronic
version thereof with the Commission).

 

13. 
Confirmation of Sale. The Investor acknowledges and agrees that such Investor’s receipt of the Company’s
signed counterpart to this Agreement, together with the Prospectus Supplement (or the filing by the Company of an electronic
version thereof with the Commission), shall constitute written confirmation of the Company’s sale of the Shares and Warrants
to such Investor.

 

14. 
Press Release; 8-K Filing. The Company and the Investor agree that the Company shall (a) prior to the opening
of the financial markets in New York City on February 6, 2020 issue a press release announcing the Offering and disclosing all
material information regarding the Offering (the “Press Release”), and (b) as promptly as practicable on February
6, 2020 file a current report on Form 8-K with the Securities and Exchange Commission including, but not limited to, a form of
this Agreement as an exhibit thereto. Effective upon the issuance of the Press Release, the Company acknowledges and agrees that
any and all confidentiality and similar obligations under any agreement, whether written or oral, between the Company, any of its
subsidiaries or any of their respective officers, directors, affiliates, employees or agents, on the one hand, and the Investor
or any of its affiliates, on the other hand, shall terminate. From and after the issuance of the Press Release, the Investor shall
not be deemed to be in possession of any material, nonpublic information received from the Company, any of its subsidiaries or
any of their respective officers, directors, employees or agents.

 

15. 
Termination. In the event that the Placement Agreement is terminated by the Placement Agent pursuant to
the terms thereof, this Agreement shall terminate without any further action on the part of the parties hereto.

 

16. 
Assignability of Agreement. The Agreement and the Investor’s rights, obligations and interest under the
Agreement, including the Terms and Conditions for Purchase of Securities, are not transferable or assignable by the Investor.

 

     

     

    

 

EXHIBIT A

MOLECULIN BIOTECH, INC.

INVESTOR QUESTIONNAIRE

 

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

 

	1.	The exact name that your Shares and Warrants are to be registered in.  You may use a nominee name if appropriate:	________________________
	2.	The relationship between the Investor 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 the response to item 1 above:	________________________
	5.	Name of DTC Participant (broker-dealer at which the account or accounts to be credited with the Shares are maintained):	________________________
	6.	DTC Participant Number:	________________________
	7.	Name of Account at DTC Participant being credited with the Shares:	________________________
	8.	Account Number at DTC Participant being credited with the Shares:	________________________

 

     

     

    

 

EXHIBIT B

FORM OF WARRANT

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