Alkaloids from the roots of Stemona cochinchinensis

Phytochemical investigation of the roots of Stemona cochinchinensis led to the isolation and structure elucidation of a new pyrido[1,2-a]azepine-type alkaloid, stemocochinamine (1), and of four new pyrrolo[1,2-a]azepine-type alkaloids, bisdehydrostemocochinine (2), isobisdehydrostemocochinine (3), neostemocochinine (4), and isoneostemocochinine (5), together with six known alkaloids. Their structures were established on the basis of extensive 1D- and 2D-NMR analyses in combination with HR-MS experiments.