A new clavam antibiotic from streptomyces clavuligerus: III. Absolute stereochemistry

Abstract

The complete stereostructure of the new antibiotic Ro 22-5417 has been established as 3-[(3S,5S)-7-oxo-l-aza-4-oxabicyclo[3.2.0]hept-3-yl]-L-alanine. This result together with the synthesis of an (3R,5R)-L-analog allowed us to postulate that clavams require the R-configura-tion at the ring juncture for β-lactamase inhibitory activity, while the opposite S-stereochemistry is essential for antifungal activity. © 1983, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.