N-OXIDES OF SOME NORDITERPENOID ALKALOIDS

Eight new N-oxides [1-8] of the norditerpenoid alkaloids aconitine, aj acine, delphinine, delphisine, deltaline, heteratisine, lappaconitine, and N-deacetyllappaconitine have been prepared with m-chloropeIbenzoi c acid. The structures of these compounds were established on the basi s of their spectroscopic data(H-1, C-13, DEPT, COSY, HETCOR, and selec tive INEPT nmr experiments). The complete nmr chemical shift assignmen ts for all eight N-oxides are reported. Table 2 shows the differences between the C-13-nmr shifts of the N-oxides compared with those of the parent alkaloids.