75731-43-0 Marcfortine A Spiro(4H,8H-(1,4)dioxepino(2,3-g)indole-8,2'(3'H)-(1H,4H-3a,9a)(iminomethano)cyclopenta(b)quinolizine)-9,11'(10H)-dione, 6',7',8',9',10',10'a-hexahydro-1',1',4,4,12'-pentamethyl-, (2'R-(2'alpha,3'aalpha,9'aalpha,10'aalpha))-