2'-De(acetylmethylamino)-2'-methylmaytansine 66584-72-3 Ansamitocin P3 Ansamitosin P3 Antibiotic C 15003P3 C 15003P3 Maytansine, 2'-de(acetylmethylamino)-2'-methyl- Maytansinol isobutyrate NSC 292222