New alkaloids of Alstonia constricta

Abstract

In the course of the isolation of reserpine from the tertiary alkaloids of Alstonia constricta root bark, a number of other alkaloids were obtained, and these alkaloids have now been the subject of further study. Alstonidine, a previously known alkaloid for which the provisional structure (6) was suggested, has now been shown to have the stereochemistry depicted in (7a). A new alkaloid, alstonilidine, has been shown to be (8). Vincamajine (9) has been identified, and two new alkaloids, O-3,4,5-trimethoxycinnamoylvincamajine (10) and 0-3,4,5-trimethoxybenzoylquebrachidine (11) have been isolated from the "reserpine concentrate". Another alkaloid, probably C43H50N4O7, appears to be a new member of the "bisindole" group.