150422-35-8 20-Demethoxy-20-(3-(((5-dimethylamino)naphthalen-1-yl)sulfonyl)amino)propylmaytansinol-3-isobutyrate Dan-pdm-3 Maytansine, 2'-de(acetylmethylamino)-20-demethoxy-20-(3-(((5-(dimethylamino)-1-naphthalenyl)sulfonyl)amino)propoxy)-2'-methyl-