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                                                                   Exhibit 10.23


                     PARTNERSHIP INTEREST PURCHASE AGREEMENT

      THIS PARTNERSHIP INTEREST PURCHASE AGREEMENT (this "PURCHASE AGREEMENT")
is made and entered into this 3rd day of August, 2001 (the "EFFECTIVE DATE"), by
and between MADEIRA-RMC L.P., a New York limited partnership (the
"Partnership"), MADEIRA MANAGEMENT COMPANY, INC., a Delaware corporation
("MADEIRA"), MERLOT MANAGEMENT COMPANY, INC., a Delaware corporation ("MERLOT")
(Madeira and Merlot are collectively referred to herein as the "SELLERS"),
ROBERT MARTIN COMPANY, LLC, a New York limited liability company, f/k/a Robert
Martin Company, a New York general partnership ("RMC"), and RMC as agent for 5/6
Skyline Realty L.L.C., a New York limited liability company ("PURCHASER").

      WHEREAS, the Partnership is a limited partnership duly organized, validly
existing, and in good standing under the laws of the State of New York;

      WHEREAS, the Partnership owns certain real property located in Westchester
County, New York, commonly known as No. 5 and No. 6 Skyline Drive,
Mid-Westchester Executive Park, Westchester, New York, as more fully described
in EXHIBIT A attached hereto and made a part hereof;

      WHEREAS, Merlot owns a forty-nine and seven tenths percent (49.7%) general
partnership interest and Madeira owns a twenty and three tenths percent (20.3%)
general partnership interest and RMC owns a thirty percent (30%) limited
partnership interest in the Partnership;

      WHEREAS, the partners in the Partnership are implementing the buy/sell
provisions of section 8.01 of the Partnership's Amended and Restated Agreement
of Limited Partnership dated as of September 1, 1994 (the "Partnership
Agreement") pursuant to the terms of this Agreement;

      WHEREAS, Madeira and Merlot have initiated the buy/sell provisions by
sending a Purchase Offer (as defined in the Partnership Agreement) dated March
8, 2001 (the "Offer Date") to RMC, and the parties have thereafter determined
that Madeira and Merlot are the Sellers and RMC, as agent for 5/6 Skyline Realty
L.L.C., is the Purchaser;

      WHEREAS, Purchaser desires to purchase from Sellers, and Sellers desire to
sell to Purchaser, all of Sellers' rights, title, and interest in the
Partnership (the "INTEREST"); and

      WHEREAS, the purchase of the Interest by Purchaser shall occur in
accordance with the terms and conditions specified herein.

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



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        1. PURCHASE AND SALE OF INTEREST.

              a. Upon the terms and conditions hereinafter set forth, Sellers
agree to sell, grant and convey, and Purchaser agrees to purchase and accept,
the Interest (as defined in the Recitals to this Purchase Agreement) for the
amount set forth below, free and clear of all liens, charges, restrictions,
encumbrances and security interests of any kind. After the purchase of the
Interest, RMC and Purchaser shall collectively hold one hundred percent
(100%) of the partnership interests in the Partnership.

              b. The net purchase price for the Interest following the
payment of Partnership debts and obligations and subject to adjustments and
prorations as provided for herein shall be Five Million Seven Hundred
Seventy-Three Thousand, Eight Hundred Thirty-One and 70/100 Dollars
($5,773,831.70) (the "PURCHASE PRICE") in cash, by bank wire transfer of
immediately available federal funds. The methodology for determining the
Purchase Price is attached hereto as EXHIBIT B.

              c. Sellers acknowledge that Purchaser is acquiring the Interest
to own, as of the Closing, the following (collectively, the "PROPERTY"):

               (i) that certain real property located in Westchester County, New
       York, commonly known as No. 5 and No. 6 Skyline Drive, Mid-Westchester
       Executive Park, Westchester, New York, as more fully described in EXHIBIT
       A attached hereto and made a part hereof (hereinafter referred to as the
       "LAND"), together with all improvements situated thereon (the
       "IMPROVEMENTS"), all fixtures used in the operation of the Land or the
       Improvements, and all other appurtenances to the Land;

               (ii) all personal property located on the Land and all supplies
       and inventory and replacements thereof now or hereafter affixed to and/or
       located at the Land and used in connection with the ownership,
       management, operation, maintenance or repair of the Land and the
       Improvements (collectively, the "PERSONAL PROPERTY"); and

               (iii) all intangible property relating to the Land, Improvements
       or the Personal Property, including, without limitation, the following
       (collectively, the "INTANGIBLE PROPERTY"): (A) all contracts and
       agreements, documents and instruments, including, without limitation, all
       leasing, service, warranty, guaranty, management, supply, employment, and
       maintenance agreements relating to, or required in connection with, the
       full use, operation, occupancy, ownership and enjoyment of the Land, the
       Improvements or the Personal Property or the business operations of the
       Partnership (collectively, the "AGREEMENTS"); (B) all certificates,
       permits, licenses, approvals or other authorizations required in
       connection with the ownership, use, operation or maintenance of the Land,
       the Improvements or the Personal Property or the business operations of
       the Partnership, and any future development or redevelopment thereof,
       from any governmental or quasi-governmental authority having jurisdiction
       over the Land or the Partnership (collectively, the "PERMITS AND
       LICENSES"); and (C) all right, title and interest in all warranties,
       plans and specifications for the Improvements and all tenant spaces,
       trade names, and development rights related to the business operations of
       the Partnership, the Land, the Improvements or the Personal Property.



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        2. INDEBTEDNESS OF THE PARTNERSHIP.

              a. The Partnership is indebted to Madeira and Merlot in the
principal amount of Six Million Two Hundred Sixty Thousand, Four Hundred
Thirty-Four and no/100 Dollars ($6,260,434) together with interest thereon in
the amount of Two Hundred Thirty-One Thousand Two Hundred Thirty-Five and no/100
Dollars ($231,235) as of the Closing Date (the "Partnership Indebtedness").

              b. Thereafter, at Closing Purchaser shall pay on behalf of the
Partnership any Partnership Indebtedness. Such payments shall be made 71% to
Merlot and 29% to Madeira.

        3. INDEBTEDNESS OF RMC.

              a. RMC is indebted to Madeira and Merlot in the principal amount
of Eight Hundred Fifty-Four Thousand, Four Hundred Ninety-Six and no/100 Dollars
($854,496) together with interest thereon in the amount of Eight Hundred
Forty-Seven Thousand, Eight Hundred Seventy-Eight and no/100 Dollars ($847,878)
as of the Closing Date (the "RMC Indebtedness").

              b. At Closing (as defined below), Purchaser shall pay the RMC
Indebtedness to Madeira and Merlot in cash, wire transfer or other readily
available funds. Such payments shall be made 71% to Merlot and 29% to Madeira.

        4. CLOSING DATE. The date on which the Closing shall occur (the
"CLOSING DATE") shall be August 2, 2001.

        5. CONDITIONS TO CLOSING.

              a. Purchaser's obligation to consummate the transactions
contemplated by this Purchase Agreement is subject to the following conditions:

                     (i) The representations and warranties of Sellers contained
              in this Agreement shall be true and correct on, and as of, the
              Closing Date, in all material respects, as though such
              representations and warranties were made on, and as of, such date.

                     (ii) From the Effective Date until the time of the Closing,
              there shall not have occurred any material and adverse change in
              the physical condition of the Property, except: (A) those changes
              caused by ordinary wear and tear; or (B) as caused directly or
              indirectly by any act or omission of Purchaser or its
              representatives, agents or employees.

                     (iii) Since the Effective Date, the operations of the
              Partnership shall have been carried out in the ordinary course of
              business and there shall not have occurred:

                            (1)    any material and adverse change in the
                                   condition (financial or otherwise) or in the
                                   overall business of the Partnership;

                            (2)    any material increase in the liabilities of
                                   the Partnership from



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                                   those liabilities listed or otherwise
                                   disclosed in the financial statements of the
                                   Partnership for the year ended December 31,
                                   2000 (the "Financial Statements"), other
                                   than those contemplated by this Agreement;
                                   and

                            (3)    any damage, destruction or loss (whether or
                                   not covered by insurance) materially and
                                   adversely affecting the Partnership.

                     (iv) Sellers shall have performed and complied with all of
              the terms, covenants, conditions and obligations of this Purchase
              Agreement, including, without limitation, the delivery
              requirements of Section 9(f) herein.

              b. Sellers' obligations to consummate the transactions
contemplated by this Purchase Agreement are subject to the following conditions:

                     (i) The representations and warranties of Purchaser
              contained in this Agreement shall be true and correct on, and as
              of, the Closing Date, in all material respects, as though such
              representations and warranties were made on, and as of, such date.

                     (ii) Purchaser shall have performed and complied with all
              of the terms, covenants, conditions and obligations of this
              Purchase Agreement, including without limitation, the delivery
              requirements of Section 9(e) herein.

                     (iii) Closing of the Debt Capitalization and Liquidating
              Distribution Agreement of even date herewith among Michaelson-RMC
              L.P., Michaelson Management Company, Inc., Michelin Management
              Company, Inc., RMC, and La Reserve Apartment-Hotel Corp.

                     (iv) Satisfaction of the RMC Indebtedness and evidence
              representing same.

                     (v) Satisfaction of the Partnership Indebtedness and
              evidence representing same.

              c. Purchaser may waive in writing any condition set forth in
Paragraph 5(a) and Sellers may waive in writing any condition set forth in
Paragraph 5(b) and require the other to effect the Closing pursuant to Paragraph
9.

      6. MUTUAL REPRESENTATIONS AND WARRANTIES. Sellers, RMC and Purchaser,
respectively, hereby represent and warrant to the others that the following are
true, accurate and complete as of the Effective Date and shall be true, accurate
and complete as of the Closing Date:

              a. Each of the Sellers, RMC and Purchaser, respectively, has the
full legal power and authority to enter into and perform this Purchase Agreement
in accordance with its terms. The execution and delivery of this Purchase
Agreement and the performance by each of the Sellers, RMC and



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Purchaser, respectively, of its obligations hereunder requires no further
action or approval by either of the Sellers, RMC or Purchaser or any other
person or entity. This Purchase Agreement is the binding obligation of each
of Sellers, RMC and Purchaser.

              b. The execution, delivery and performance of this Purchase
Agreement and all documents in connection therewith are not in contravention of
or in conflict with any deed of trust, agreement or undertaking to which either
of the Sellers, RMC or Purchaser, respectively, is a party or by which either of
the Sellers, RMC or Purchaser, respectively, or any of their respective property
or assets, including the Property and the Interest, may be bound or affected.

      7. SELLERS' REPRESENTATIONS AND WARRANTIES. Sellers hereby represent and
warrant to the Purchaser that the following are true, accurate and complete as
of the Effective Date and shall be true, accurate and complete as of the Closing
Date:

              a. No bankruptcy, insolvency, rearrangement or similar action or
proceeding, whether voluntary or involuntary, is pending or, to the best of
either Seller's knowledge, threatened against either Seller.

              b. Each Seller is the owner of its Interest and has not pledged,
sold, transferred or hypothecated its Interest except as provided herein.

              c. There is no action, claim, demand, litigation, proceeding or
governmental investigation, at law or in equity, pending or, to the best of
either Seller's knowledge, threatened against or related to the Property or the
Partnership.

      8. DAMAGE, DESTRUCTION AND CONDEMNATION. In the event of any fire or other
casualty costing more than Three Million Dollars to repair or in the event any
condemnation proceedings are instituted with respect to all or more than 25% of
the rentable area of the Property prior to the Closing, Purchaser shall have the
right to terminate this Purchase Agreement by written notice to either of the
Sellers no later than the date that is fifteen (15) days after notice of such
event. The Closing Date shall, if necessary, be extended to coincide with the
expiration of such fifteen (15) day period.

      9. CLOSING.

              a. The Closing (the "CLOSING") shall be held on the Closing Date
in the offices of UBS Realty Investors LLC, 10 East 50th Street, New York, New
York, or at any other location mutually acceptable to the parties hereto.

              b. At the Closing, the parties shall apportion the real estate
taxes, utilities, rents and other expenses incurred or income received from the
Property as of the Closing Date in an equitable manner. Such taxes, utilities,
rents, other expenses shall be treated as a separate line item on the settlement
sheet at Closing and shall be netted together and satisfied by a separate
payment by either the Seller or Purchaser whichever of them shall be determined
to have a net payment obligation to the other hereunder. Rents received from
tenants of the Property after Closing shall be applied first to rent due during
the then current month and then to any rent accrued and unpaid as of the Closing
in which case



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70% of such rents shall be paid to Sellers and the balance to Purchaser. Any
transfer taxes, shall be paid by Sellers. RMC shall prepare and file any
transfer tax returns required to be filed, and Sellers shall duly and timely
execute any such returns, in respect of the purchase hereunder.

              c. At the Closing, Purchaser shall pay to Sellers the Purchase
Price and the RMC Indebtedness.

              d. At the Closing, the Partnership shall pay to Sellers the
Partnership Indebtedness.

              e. At the Closing, Purchaser shall execute and deliver to Sellers,
in form and substance reasonably satisfactory to Sellers' counsel, the
following:

                     (i) Certificate of dissolution of the Partnership.

                     (ii) Notices to tenants and service providers of the
              Property regarding the change in ownership of the Property
              reasonably acceptable to the parties.

                     (iii) Such other documents, forms, and other items as may
              be requested by Sellers or their counsel and as may be reasonably
              and customarily required to close similar transactions.

              f. At the Closing, Sellers shall execute and deliver, or cause the
Partnership to execute and deliver, to Purchaser, in form and substance
reasonably satisfactory to Purchaser's counsel, the following:

                     (i) Instructions to the Partnership to register on the
              Partnership's books and records the transfer of the Interest from
              Sellers to Purchaser.

                     (ii) FIRPTA affidavit.

                     (iii) Such other documents, forms and other items as may be
              requested by Purchaser or its counsel and may be reasonably and
              customarily required to close similar transactions.

                     (iv) The originals of all notes duly marked "paid in full"
              or other language of similar import in respect of the Partnership
              Indebtedness and RMC Indebtedness and/or such other evidence of
              satisfaction of the Partnership Indebtedness and RMC Indebtedness
              as Purchaser may reasonably request.

              g. As soon as practicable after Closing, Purchaser shall execute
and deliver to Sellers, in form and substance reasonably satisfactory to
Sellers' counsel, a final accounting of all activities of the Partnership as of
the Closing Date and Sellers' share of all such activities and the parties shall
reprorate, if necessary, the closing adjustments to reflect final accounting of
the property for 2001.


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      10. INDEMNITY.

              a. Sellers and Purchaser shall indemnify, defend and hold the
other harmless from and against, and shall reimburse the other with respect to,
any and all claims, demands, causes of action, losses, damages, liabilities,
costs and expenses (including reasonable attorneys' fees and court costs,
whether suit is instituted or not), asserted against or actually incurred by the
indemnified party by reason of or arising out of the discovery following the
Closing of the breach or material misstatement by the indemnifying party of any
representation, warranty or covenant contained in this Purchase Agreement.

              b. RMC and Purchaser shall indemnify, defend and hold Sellers
harmless from and against, and shall reimburse the Sellers with respect to, any
and all claims, demands, causes of action, losses, damages, liabilities, costs
and expenses (including reasonable attorneys' fees and court costs, whether suit
is instituted or not), asserted against or actually incurred by the indemnified
parties after the Closing Date by reason of or arising out of the acts or
omissions of the Partnership or otherwise relating to the Partnership after the
Closing Date or the Property after the Closing Date.

              c. Subject to the last sentence of this section, Sellers shall
indemnify, defend and hold RMC and Purchaser harmless from and against, and
shall reimburse RMC and Purchaser with respect to, any and all claims, demands,
causes of action, losses, damages, liabilities, costs and expenses (including
reasonable attorneys' fees and court costs, whether suit is instituted or not),
asserted against or actually incurred by the indemnified parties after the
Closing Date by reason of or arising out of the acts or omissions of the
Partnership or otherwise relating to the Partnership prior to the Closing Date
or the Property prior to the Closing Date. In the event of a third party claim
against the Partnership arising out of circumstances occurring prior to the
Closing Date and the Purchaser pays or compromises such claim, Sellers shall be
responsible to Purchaser for such costs on a 70 to 30 basis with RMC's liability
capped at $760,445.

              d. The indemnified party must give the indemnifying party notice
of the indemnified claim within one year from the Closing in order to avail
itself of the remedies provided in this section.

      11. PRE-CLOSING REMEDIES.

              a. In the event of a breach or threatened breach of this Agreement
by either party, the non-breaching party shall have all rights and remedies that
may be available at law or equity or the Partnership Agreement.

      12. BROKERAGE.

              a. Except as otherwise disclosed in writing to Purchaser, Sellers
warrant to Purchaser and RMC that no broker is entitled to any brokerage
commission or fee arising out of this transaction, and Sellers shall indemnify,
hold and defend Purchaser and RMC harmless against any losses, liabilities,
expenses and claims resulting from a breach of the foregoing warranty.

              b. Except as otherwise disclosed in writing to Sellers, Purchaser
and RMC warrant to Sellers that no broker is entitled to any brokerage
commission or fee arising out of this transaction, and



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Purchaser and RMC shall indemnify, hold and defend Sellers harmless against any
losses, liabilities, expenses and claims resulting from a breach of the
foregoing warranty.

      13. GENERAL PROVISIONS.

              a. The terms and conditions of this Purchase Agreement shall be
binding upon, and inure to the benefit of, the parties hereto and their
respective heirs, successors, permitted assigns and legal representatives.

              b. The parties agree to take such further actions and to cause the
Partnership to take such actions as may be necessary in order to consummate the
transactions contemplated by this Purchase Agreement.

              c. The representations, warranties and indemnities of Sellers
contained in this Purchase Agreement or in any instrument, document or agreement
delivered by Sellers pursuant hereto shall survive the consummation of the
transfer of the Interest, and shall not be merged therein.

              d. Any notice required or permitted hereunder shall be deemed to
have been received either: (i) when delivered by hand to Purchaser or one of the
Sellers as evidenced by a signed receipt therefor; or (ii) when delivered by the
United States postal service, postage prepaid, or by a recognized commercial air
or local courier service, addressed as follows (or addressed in such other
manner as the party being notified shall have requested by such written notice
to the other party), except that refusal to accept delivery of notice shall be
deemed to be receipt hereunder:

              If to Madeira or Merlot:

              c/o UBS Realty Investors LLC
              10 East 50th Street, 15th floor
              New York, New York 10022
              Attn:  Scott M. Dalrymple

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

              Patton Boggs LLP
              2550 M Street, NW
              Washington, D.C. 20037
              Attn:  Ross E. Eichberg, Esq.

              If to RMC:

              Robert Martin Company, LLC
              100 Clearbrook Road
              Elmsford, NY  10523
              Attn:  Martin S. Berger



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

              Robert Martin Company, LLC
              100 Clearbrook Road
              Elmsford, NY  10523
              Attn:  Lloyd Roos

              e. This Purchase Agreement constitutes the entire agreement
between the parties concerning the subject matter hereof and otherwise
supersedes all prior agreements or undertakings with respect to each and every
provision of this Purchase Agreement.

              f. In the event that any one or more of the provisions contained
in this Purchase Agreement are held to be invalid, illegal or unenforceable in
any respect, such invalidity, illegality or unenforceability shall not affect
any other provision hereof, and this Purchase Agreement shall be construed as if
such invalid, illegal or unenforceable provision had not been contained herein.

              g. Any paragraph heading contained in this Purchase Agreement
shall be for convenience of reference only and shall not affect the construction
or interpretation of any provision of this Purchase Agreement.

              h. No failure by Purchaser, Sellers or the Partnership to insist
upon the strict performance of any term of this Purchase Agreement shall
constitute a waiver of any such breach or any subsequent breach of any such
term. No term of this Purchase Agreement and no breach thereof shall be waived,
altered or modified except by written instrument. No waiver of any breach shall
affect or alter this Purchase Agreement, but each and every term of this
Purchase Agreement shall continue in full force and effect with respect to any
other then existing or subsequent breach thereof.

              i. This Purchase Agreement shall be governed by and construed
according to the laws of the State of New York.

              j. This Purchase Agreement may not be assigned without the express
written consent of the other party, provided, however, that Purchaser shall have
the right, after notice and without the consent of Sellers, to assign his
interest in the Purchase Agreement to an entity controlled by Purchaser or to a
trust benefiting members of Purchaser's family.


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      IN WITNESS WHEREOF, the parties hereto have executed this Purchase
Agreement under seal as of the date first written above.

MADEIRA-RMC L.P.

BY:      MADEIRA MANAGEMENT COMPANY, INC.,
         its managing general partner

         By: /s/  Stephen J. Spey             (Seal)
            ---------------------------------
         Name:    Stephen J. Spey
            ---------------------------------
         Its:     Vice President
            ---------------------------------

MADEIRA MANAGEMENT COMPANY, INC.


         By: /s/  Stephen J. Spey             (Seal)
            ---------------------------------
         Name:    Stephen J. Spey
            ---------------------------------
         Its:     Vice President
            ---------------------------------



MERLOT MANAGEMENT COMPANY, INC.



         By: /s/  Stephen J. Spey             (Seal)
            ---------------------------------
         Name:    Stephen J. Spey
            ---------------------------------
         Its:     Vice President
            ---------------------------------


ROBERT MARTIN COMPANY, LLC                   ROBERT MARTIN COMPANY, LLC,
                                             AS AGENT FOR
                                             5/6 SKYLINE REALTY L.L.C.


By:      /s/ Robert F. Weinberg     (Seal)   By: /s/ Robert F. Weinberg   (Seal)
     -------------------------------            ---------------------------
         Robert F. Weinberg, Manager            Robert F. Weinberg, Manager


By:    /s/ Martin S. Berger         (Seal)   By: /s/ Martin S. Berger     (Seal)
     -------------------------------             --------------------------
       Martin S. Berger, Manager                 Martin S. Berger, Manager



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