The synthesis and reactivity of optically pure amino acids bearing side-chain thioamides

The synthesis and reactivity of fully protected thioamide analogues of aspa ragine: and glutamine are described. A key feature of the synthetic strateg ies employed was the ability to perform selective thiations on multiple car bonyl-containing substrates. Also described are the preparations of thioami de derivatives of phenylalanine. The utility of these amino acid derivative s for solid-phase peptide synthesis is discussed.