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The use of N-urethane-protected N-carboxyanhydrides (UNCAs) in amino acid and peptide synthesis

✍ Scribed by Jean-Alain Fehrentz; Corine Genu-Dellac; Muriel Amblard; Franclois Winternitz; Albert Loffet; Jean Martinez

Book ID
105360085
Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
637 KB
Volume
1
Category
Article
ISSN
1075-2617

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✦ Synopsis

Abstract

N‐Urethane‐protected N‐carboxyanhydrides (UNCAs) are very reactives. They have been successfully used in peptide synthesis, in both solution and solid phase. We have demonstrated that UNCAs are interesting starting materials for the synthesis of various amino acid derivatives. Chemoselective reduction of UNCAs with sodium borohydride led the corresponding N‐protected β amino alcohols. Reaction of UNCAs with Meldrum's acid, followed by cyclisation, yielded enantiomerially pure tetramic acid derivatives. Diastereoselective reduction of tetramic acid derivatives produced (4__S__,5__S__)‐N‐alkoxycarbonyl‐4‐hydroxy‐5‐alkylpyrrolidin‐2‐ones derived from amino acids, which after hydrolysis yielded statine and statine analogues. Tetramic acid derivatives could also be obtained by reaction of UNCAs with benzyl ethyl followed by hydrogenolytic deprotection and decarboxylation. UNCAs also reacted with phosphoranes to produce the ketophosphorane in excellent yields. Subsequent oxidation with oxone or with [bis(acetoxy)‐iodol]‐benzene produced vicinal tricarbonyl derivatives. These reactions usually proceeded smoothly and with high yields.

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