Studies of Peptide Antibiotics. XXVI. Syntheses of Cyclodipeptides containing N^δ-p-Aminobenzenesulfonyl Ornithine Residue

Abstract

A cyclo-N^δ-p-aminobenzenesulfonyl-L-ornithyl-L-leucyl (LL-X) was prepared through the cyclization reaction of N^δ-p-aminobenzenesulfonyl-L-ornithyl-L-leucine ethyl ester with methanolic ammonia. Other three diastereomeric cyclodipeptides (DD-X, LD-X, and DL-X) and cyclo-N^δ-p-aminobenzenesulfonyl-ornithyl-glycyls (L and D form) were synthesized in the same manner. All p-aminobenzenesulfonyl cyclodipeptides showed no antibacterial activity against Escherichia coli and Bacillus subtilis even at the concentration of 1000 μg/ml.