THE OXIDATION OF DITERPENOID ALKALOIDS

Abstract

The highly oxygenated diterpenoid alkaloids possessing the same C—N ring structure fall into two groups: group A containing the aconitine-like bases in which the C-6 methoxyl is α-oriented, and group B containing the lycoctonine-like bases in which the C-6 methoxyl is β-oriented. The alkaloids of both groups are oxidized rapidly at room temperature by neutral potassium permanganate. The oxidation dealkylates the amino group in the bases of group A giving rise to secondary bases while it converts the bases of group B to the corresponding lactams. The different course of the oxidation from one group to the other is due to the different orientation of the C-6 methoxyl, and can be used to determine the stereochemistry at C-6.