86683-20-7 Antibiotic C 33196E5R C 33196E5R Geldanamycin, 18,21-didehydro-6,17-didemethoxy-12-O-demethyl-1,8,21-dideoxo-18,21-dihydroxy-15-methoxy-6-methyl-11-O-methyl-, (6S,15R)-