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

The synthesis and reactivity of fully protected thioamide analogues of asparagine and glutamine are described. A key feature of the synthetic strategies employed was the ability to perform selective thiations on multiple carbonyl-containing substrates. Also described are the preparations of thioamide derivatives of phenylalanine. The utility of these amino acid derivatives for solid-phase peptide synthesis is discussed.