Synthesis of Peptide Thioacids at Neutral pH Using Bis(2-sulfanylethyl)amido Peptide Precursors

Reaction of bis(2-sulfanylethyl)amido (SEA) peptides with trilsopropylsilylthiol in water at neutral pH yields peptide thiocarboxylates. An alkylthioester derived from beta-alanine was used to trap the released bis(2-sulfanylethyl)amine and displace the equilibrium toward the peptide thiocarboxylate.