19772-79-3 NSC180540 Spiro[1H,15aH-furo[2',3':7,8]indolizino[8,1-cd]carbazole-2(2aH),8'(9'H)-[1H,6H,7H,17aH]furo[2',3':7,8]indolizino[8,1-cd]pyrido[1,2,3-lm]carbazole]-7-carboxylic acid, 2',2'a,4,4',5,5',6,6'a,8,13,14,14'c,15',16'-tetradecahydro-14'c-hydroxy-11'-methoxy-, methyl ester,[2'aS-[2'a.alpha.,5'aS*,6'a.beta.,8'.alpha.(2aS*,5aS*,12bS*,15aS*),14'bS*,14c.alpha.,17'a.beta.]]- Spiro[1H,15aH-furo[2',3':7,8]indolizino[8,1-cd]carbazole-2(2aH),8'(9'H)-[1H,6H,7H,17aH]furo[2',3':7,8]indolizino[8,1-cd]pyrido[1,2,3-lm]carbazole]-7-carboxylic acid, 2',2'a,4,4',5,5',6,6'a,8,13,14,14'c,15',16'-tetradecahydro-6'a-hydroxy-11'-methoxy-, methyl ester Vobtusin Vobtusine