Facile synthesis of C-terminal peptide thioacids under mild conditions from N-sulfanylethylanilide peptides

A facile procedure has been developed for the synthesis of C-terminal peptide thioacids under mild conditions. A series of N-sulfanylethylanilide peptides prepared using Fmoc-based solid-phase peptide synthesis were successfully converted to the corresponding thioacids via a hydrothiolysis reaction in a phosphate buffer with only trace epimerization of the C-terminal amino acid.