Cytotoxic Alkaloids from the Flowers ofSenna spectabilis

Three new alkaloids, 3(R)-benzoyloxy-2(R)-methyl-6(R)-(11'-oxododecyl)-piperidine (3), 5-hydroxy-2-methyl-6-(11'-oxododecyl)-pyridine (4) and 5-hydroxy-2-methyl-6-(11'-oxododecyl)-pyridine N-oxide (5), together with a known alkaloid, (-)-cassine (1), were isolated from the flowers of Senna spectabilis. A derivative, N,O-diacetylcassine (2), was semisynthesized. Their structures and stereochemistry were established on the basis of spectroscopic...