Degradation studies of antibiotic MDL 62,879 (GE2270A) and revision of the structure

Fragments of the thiopeptide antibiotic MDL 62,879 (GE2270A) were prepared under mild degradation conditions. Their structures were determined by spectroscopic techniques and by comparison to synthetic reference thiazolyl dipeptides. The two thiazolyl amino acids have stereocenters with S configurations and their sequence is reversed with respect to the structure previously proposed for MDL 62,879.