Studies on Peptides. XCVI. Behavior of S-Acetamidomethylcysteine Sulfoxide under Deprotecting Conditions in Peptide Synthesis

Abstract

The sulfoxide of Boc-Cys (S-acetamidomethyl)-OH was prepared by oxidation with sodium perborate. Mercuric acetate and iodine failed to cleave the S-protecting group from the sulfoxide. Hydrogen fluoride and methanesulfonic acid partially converted the sulfoxide to S-p-methoxyphenylcysteine in the presence of anisole. A reducing reagent, thiophenol, converted the sulfoxide to acetamidomethyl phenyl sulfide and N^α-Boc-S-(phenylthio) cysteine.