(-)-Tsukushinamine-A (1) and (-)-tsukushinamine-B (2), new cagetype lupin alkaloids from Sophora franchetiana Dunn (Leguminosae), were synthesized by means of intramolecular photocyclization from a common lupin alkaloid (-)-rhombifoline (7), coexisting in the same plant. The other (-)-cytisine-type alkaloids, (-)-N-methylcytisine (9) and (-)-N-ethylcytisine (8), were also transformed into the (-)-tsukushinamine-type alkaloids (4-6) in the same way.
Abstract A new lupinalkaloid, (−)- N -ethylcytisine, was isolated from the fresh flowers of Echinosophorakoreensis . Its structure has been confirmed b