Diterpenoid alkaloids from Delphinium davisii

Abstract

Three new hetisane-type diterpenoid alkaloids, davisinol (6), 18-benzoyldavisinol (7), and Davisin (9) have been isolated from Delphinium davisii Munz. and their structures established by detailed spectroscopic studies. Accurate H-1- and C-13-NMR assignments have been made for kobusine (8), a related hetisane-type alkaloid, and karakoline (5), a norditerpenoid alkaloid. The known norditerpenoid alkaloids 14-acetylperegrine (4), 6-deacetylperegrine (3), and karakoline (5) and the diterpenoid alkaloids hetisine and hetisinone were also isolated.