Studies on the constituents of Picrasma quassioides BENNET. II. On the alkaloidal constituents.

Two new alkaloids, 4, 9-dimethoxy-1-vinyl-β-carboline (XI) and β-carbolin-1-yl 3-(4, 8-dimethoxy-β-carbolin-1-yl)-1-methoxypropyl ketone (XII) were isolated from the wood of Picrasma quassioides BENNET (Simaroubaceae) together with known alkaloids, 1-ethyl-4-methoxy-β-carboline (VI), 4-methoxy-1-vinyl-β-carboline (VII), 4, 8-dimethoxy-1-vinyl-β-carboline (VIII), canthin-6-one (IX), and 5-methoxycanthin-6-one (X). The structures of these alkaloids were elucidated on the basis of spectroscopic evidence.