Synonyms: Corynoxan-16-carboxylicacid, 16,17-didehydro-17-methoxy-2-oxo-, (16E,20a)-; Isorhynchophyllic acid; Isorhyncophyllic acid;Spiro[3H-indole-3,1'(5'H)-indolizine]-7'-acetic acid,6'-ethyl-1,2,2',3',6',7',8',8'a-octahydro-a-(methoxymethylene)-2-oxo-, [1'S-[1'a,6'a,7'b(E),8'aa]]-