Synthetic study on peptide antibiotic nisin. I. The synthesis of ring A

Abstract

Synthesis of the ring A, a cyclic sulfide peptide part containing dehydroalanine residue, in peptide antibiotic nisin was successfully achieved by applications of two novel procedures. First, a sulfide ring was derived from a cyclic disulfide peptide by desulfurization with P(Et//2N)//3. Secondly, for the preparation of dehydroanalyl residue, a simple and convenient method through Hofmann degradation of 2,3-diaminopropionyl residue was newly exploited in the presence of sulfide linkage.