Synonyms: NSC 180540;Vobtusin;methyl (2S,2aS,3a'R,4a'R,5aR,12bR,12b'R,12c'R,15aR,15a'S,17a'S)-12c'-hydroxy-10'-methoxy-2',3',4,4a',5,6,8,12c',13,13',14,14',17',17a'-tetradecahydro-4'H,5'H,16'H-spiro[furo[2',3':7,8]indolizino[8,1-cd]carbazole-2,6'-furo[2',3':7,8]indolizino[8,1-cd]pyrido[1,2,3-lm]carbazole]-7-carboxylate