Synthesis 2006(16): 2659-2664  
DOI: 10.1055/s-2006-942487
© Georg Thieme Verlag Stuttgart · New York

Use of Silyl Ester and Enamine Protection for an Efficient Alternate Synthesis of (1S,2S,5R,6S)-2-[(2′S)-(2′-Amino)propionyl]aminobicyclo[3.1.0]hexane-2,6-dicarboxylic Acid Hydrochloride (LY544344·HCl)

Jared W. Fennell*, Michael J. Semo, David D. Wirth, Radhe K. Vaid
Chemical Product Research and Development, Tippecanoe Laboratories, Eli Lilly and Company, Lafayette, IN 47902, USA
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Further Information

Publication History

Received 28 February 2006
Publication Date:
12 July 2006 (online)


An alternate synthesis of title compound (5) using N-(2-methoxycarbonyl-1-methylvinyl)-l-alanine sodium salt (6) and 2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (1) was successfully completed. Incorporation of silyl ester protection and the use of an enamine-protecting group allowed for the elimination of several processing steps.


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KF analysis was used to determine quantity of water to add to obtain a 10% by weight solution of water prior to addition to anti-solvent.