4,24-Dioxa-9,22-diazatetracyclo[19.3.1.110,14.03,5]hexacosane, maytansine deriv. 66584-72-3 Ansamitocin P 3 Ansamitocin P-3 MAYTANSINE DERIV Maytansine, 2'-de(acetylmethylamino)-2'-methyl- Maytansinol isobutyrate NSC292222 TAM-330 Tam 330