Herbimycin A 1MG. Herbimycin A, CAS Number: 70563-58-5, Molecular Formula: C30H42N2O9, Molecular Weight: 574. 7, Purity: greater than or equal to 98% by HPLC, Appearance: Yellow lyophilized solid, Synonym: (15R)-17-demethoxy-15-methoxy-11-O-methyl-geldanamycin, Size: 1MG