Synthetic studies on antibiotic validamycins. Part 11. Synthesis of validamycin A

Abstract

The antibiotic validamycin A (1a) has been synthesized for the first time (as its undeca-O-acetate) by glycosylation of the partially protected derivative (8) of the aglycone, validoxylamine A (2a), with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl chloride (11), followed by deprotection, thereby establishing the structure previously assigned. The totally O-acetytated derivative (19) of 7-deoxyvalidemycin A has been synthesized in a similar fashion.