Synonyms: 1H,9H-1,4-Ethano-9a,4a-(iminoethano)pyrano(3,4-b)indole-13-acetic acid, alpha-ethylidene-4-formyl-3,4-dihydro-9-methyl-3-oxo-, methyl ester;1H,9H-1,4-Ethano-9a,4a-(iminoethano)pyrano[3,4-b]indole-13-acetic acid, .alpha.-ethylidene-4-formyl-3,4-dihydro-9-methyl-3-oxo-, methyl ester