3-De(2-(acetylmethylamino)propionyloxy)-3-hydroxymaytansine butyrate (ester) 66547-09-9 Ansamitocin P-3' Antibiotic C 15003P3' C 15003 P-3' Maytansine, 3-de(2-(acetylmethylamino)propionyloxy)-3-hydroxy-, butyrate (ester) Maytansine, O(sup 3)-de(2-(acetylmethylamino)-1-oxopropyl)-O(sup 3)-(1-oxobutyl)- (9CI) Maytansinol butyrate