Studies of Peptide Antibiotics. XXXV. Synthesis of Gramicidin S by a Fragment Solid-Phase Method

Abstract
In order to examine the usefulness of a fragment condensation procedure in solid-phase peptide synthesis, gramicidin S (GS) was synthesized by three different procedures such as stepwise elongation, fragment condensation with dipeptide fragments, and fragment condensation with tripeptide fragments. The two fragment condensation procedures gave intermediate peptide derivatives in high yields and in high purity. Such differences in the purity of the intermediate peptides disappeared in the final product, GS dihydrochloride. The GS synthesized by the three procedures exhibited the same antibacterial activities as those of natural GS.