Chemical Study of Alkaloids from Corydalis bungeana.

From the herbs of CORYDALIS BUNGEANA, 16 alkaloids were isolated; 3 of them were identical with acetylcorynoline ( 2), corynoline ( 5), protopine ( 9), which had been obtained before from this plant. A further 11 known alkaloids: dihydrosanguinarine ( 1), acetylisocorynoline ( 3), 11-epicorynoline ( 4), corycavine ( 6), bicuculine ( 7), 12-hydroxycorynoline ( 8), scoulerine ( 12), cheilanthifoline ( 13), yuziphine ( 14), isoboldine ( 15), noryuziphine ( 16) were isolated for the first time from this plant. The tenth, named (+)-bungeanine, is a new alkaloid. Its structure has been established to be N-nor-5,14-dehydroacetylcorynoline. The conformation of (+)-bungeanine in solution is also discussed.