SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


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


                    Under the Securities Exchange Act of 1934

                                  SCHEDULE 13G


             INFORMATION STATEMENT PURSUANT TO RULES 13d-1 AND 13d-2
                    UNDER THE SECURITIES EXCHANGE ACT OF 1934




                         Manhattan Pharmaceuticals, Inc.
                       -----------------------------------
                                (Name of Issuer)



                         Common Stock, $0.001 par value
                       ----------------------------------
                         (Title of Class of Securities)



                                    563118207
                                 (CUSIP Number)

                                February 21, 2003
                ------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)



Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

      |_|  Rule 13d-1(b)
      |X|  Rule 13d-1(c)
      |_|  Rule 13d-1(d)



                                Page 1 of 7 Pages


SCHEDULE 13G CUSIP No. 563118207 Page 2 of 7 Pages - ------------------------------------------------------------------------------- 1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Oleoyl-Estrone Developments SL - -------------------------------------------------------------------------------- 2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |_| (b) |_| - -------------------------------------------------------------------------------- 3) SEC USE ONLY - -------------------------------------------------------------------------------- 4) CITIZENSHIP OR PLACE OF ORGANIZATION Barcelona, Spain - ------------------------------------------------------------------------------- 5) SOLE VOTING POWER 4,157,037 NUMBER ------------------------------------------------------ OF 6) SHARED VOTING POWER SHARES BENEFICIALLY 0 OWNED BY ------------------------------------------------------ EACH 7) SOLE DISPOSITIVE POWER REPORTING PERSON 4,157,037 WITH ------------------------------------------------------ 8) SHARED DISPOSITIVE POWER 0 - ------------------------------------------------------------------------------- 9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,157,037 - ------------------------------------------------------------------------------- 10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 17.8% - ------------------------------------------------------------------------------- 12) TYPE OF REPORTING PERSON CO - -------------------------------------------------------------------------------

SCHEDULE 13G CUSIP No. 563118207 Page 3 of 7 Pages - ------------------------------------------------------------------------------- 1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Joan Pons Gimbert - ------------------------------------------------------------------------------- 2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |_| (b) |_| - ------------------------------------------------------------------------------- 3) SEC USE ONLY - ------------------------------------------------------------------------------- 4) CITIZENSHIP OR PLACE OF ORGANIZATION Spain - ------------------------------------------------------------------------------- 5) SOLE VOTING POWER NUMBER 4,157,037(1) OF ------------------------------------------------------ SHARES 6) SHARED VOTING POWER BENEFICIALLY OWNED BY 0 EACH ------------------------------------------------------ REPORTING 7) SOLE DISPOSITIVE POWER PERSON WITH 4,157,037(1) ------------------------------------------------------ 8) SHARED DISPOSITIVE POWER 0 - ------------------------------------------------------------------------------- 9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,157,037(1) - ------------------------------------------------------------------------------- 10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 17.8% - ------------------------------------------------------------------------------- 12) TYPE OF REPORTING PERSON IN - ------------------------------------------------------------------------------- - -------------------------------- (1) Voting and dispositive power is exercised by Mr. Pons in his capacity as Chief Executive Officer of Oleoyl-Estrone Developments SL ("OED"). Mr. Pons disclaims beneficial ownership of the shares owned by OED.

Schedule 13G - ------------ Item 1(a). Name of Issuer: Manhattan Pharmaceuticals, Inc. Item 1(b). Address of Issuer's Principal Executive Offices: 787 Seventh Avenue, 48th Floor New York, New York 10019 Item 2(a). Name of Persons Filing: Oleoyl-Estrone Developments SL Joan Pons Gimbert Item 2(b). Address of Principal Business Office or, if None, Residence: The business address of Oleoyl-Estrone Developments SL is: Josep Samitier 1-5 Barcelona Science Park 08028 Barcelona, Spain The business address of Joan Pons Gimbert is: c/o Oleoyl-Estrone Developments Josep Samitier 1-5 Barcelona Science Park 08028 Barcelona, Spain Item 2(c). Citizenship or Place of Organization: Oleoyl-Estrone Developments SL is a company of unlimited duration registered in the Registro Mercantil of Barcelona. Joan Pons Gimbert is a citizen of Spain. Item 2(d). Title of Class of Securities: Common Stock, $0.001 par value per share Item 2(e). CUSIP Number: 563118207 Item 3. If this statement is filed pursuant to ss.ss. 240.13d-1(b), or 240.13d-2(b) or (c), check whether the person filing is a: (a) |_| Broker or Dealer Registered Under Section 15 of the Act (15 U.S.C. 78o) (b) |_| Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c)

(c) |_| Insurance Company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c) (d) |_| Investment Company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8) (e) |_| Investment Adviser in accordance with ss. 240.13d-1(b)(1)(ii)(E) (f) |_| Employee benefit plan or endowment fund in accordance with ss. 240.13d-1(b)(1)(ii)(F) (g) |_| Parent Holding Company or control person in accordance with ss.240.13d-1(b)(ii)(G) (h) |_| Savings Association as defined in ss.3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813) (i) |_| Church plan that is excluded from the definition of an investment company under ss.3(c)(15) of the Investment Company Act of 1940 (15 U.S.C. 80a-3) (j) |_| Group, in accordance with ss.240.13d-1(b)(ii)(J) Item 4. Ownership. (a) Amount beneficially owned: 4,157,037 (b) Percent of class: 17.8% (c) Number of shares as to which such person has: (i) Sole power to vote or to direct the vote: 4,157,037 (ii) Shared power to vote or to direct the vote: 0 (iii) Sole power to dispose or to direct the disposition of: 4,157,037 (iv) Shared power to dispose or to direct the disposition of: 0 Item 5. Ownership of Five Percent or Less of a Class. Not applicable Item 6. Ownership of More than Five Percent on Behalf of Another Person. Not applicable Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company. Not applicable Item 8. Identification and Classification of Members of the Group.

Not applicable Item 9. Notice of Dissolution of Group. Not applicable Item 10. Certification. By signing below, each of the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURES ---------- After reasonable inquiry and to the best knowledge and belief of the undersigned, each of the undersigned certifies that the information set forth in this Statement is true, complete and correct. Oleoyl-Estrone Developments SL By: /s/ Joan Pons Gimbert ------------------------------- Joan Pons Gimbert Chief Executive Officer Joan Pons Gimbert /s/ Joan Pons Gimbert --------------------------------- Joan Pons Gimbert Dated as of March 25, 2004

Agreement of Joint Filing Pursuant to 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended, the undersigned hereby confirm the agreement by and among them to join in the filing on behalf of each of them of a Statement on Schedule 13G and any and all amendments thereto, and that this Agreement be included as an Exhibit to such filing. This Agreement may be executed in any number of counterparts each of which shall be deemed to be an original and all of which together shall be deemed to constitute one and the same Agreement. IN WITNESS WHEREOF, each of the undersigned has executed this Agreement. OLEOYL-ESTRONE DEVELOPMENTS SL Dated: March 25, 2004 By: /s/ Joan Pons Gimbert --------------------------------- Joan Pons Gimbert Chief Executive Officer JOAN PONS GIMBERT Dated: March 25, 2004 /s/ Joan Pons Gimbert ------------------------------------ Joan Pons Gimbert