Trimethylacetamidomethyl (Tacm) Group, a New Protecting Group for the Thiol Function of Cysteine1)

Abstract

S-Trimethylacetamidomethyl-L-cysteine [Cys(Tacm)] was easily prepared from N-hydroxymethyltrimethylacetamide and L-cysteine in trifluoroacetic acid. The S-Tacm group is stable to HF, but cleavable with mercury(II) acetate in trifluoroacetic acid or iodine in aqueous acetic acid. Cys(Tacm) is less susceptible to sulfoxide formation than three related groups, i.e., acetamidomethyl (Acm), benzamidomethyl (Bam) and (2-oxo-1-pyrrolidinyl)methyl (Pym). © 1990, The Pharmaceutical Society of Japan. All rights reserved.