Synthesis 2002(11): 1499-1501
DOI: 10.1055/s-2002-33343
SHORTPAPER
© Georg Thieme Verlag Stuttgart · New York

A Convenient Synthesis of N-Fluorenylmethoxycarbonyl-N-Methyl-l-
Cysteine Derivatives [Fmoc,Me-Cys(R)-OH]

Jia-Feng Liu, Xiao-Xia Tang, Biao Jiang*
Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, P. R. China
Fax: +86(21)64166128; e-Mail: jiangb@pub.sioc.ac.cn;
Further Information

Publication History

Received 18 March 2002
Publication Date:
23 August 2002 (online)

Abstract

The synthesis of N-fluorenylmethoxycarbonyl-N,S-dimethyl-l-Cysteine (1) [Fmoc,Me-Cys(Me)-OH] and N-fluor­enylmethoxycarbonyl-N-methyl-S-acetamidomethyl-l-Cysteine (2) [Fmoc,Me-Cys(Acm)-OH] is reported. The synthesis is characterized by a convenient two-step procedure from (R)-thiazolidine-4-carboxylic acid (3) via reduction and subsequent protection. Crystals of 1, which have been analyzed by single-crystal X-ray crystallography, are obtained after a simple crystallization at the end of the process, without purification of intermediates.

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It was reported that the sodium in liquid ammonia reduction of l-thiazolidine-4-carboxylic acid gave dimeric product. [4] [10] By keeping a low concentration of the acid [4] or adding one molecular portion of water, [10] dimerization was avoided. However, from our three parallel experiments following (1) low concentration procedure, (2) water addition treatment, and (3) addition of one molecular portion of water and keeping the low concentration of the acid, the best result was obtained from the low concentration procedure.