Alkaloid N-oxides. A review of recent developments

The preparation, characterization and chemistry of alkaloid N-oxides is reviewed. Because the literature on amine N-oxides is more extensive for animals than for plants, a brief resumé of the pharmacology, metabolism, and toxicity of N-oxides is given. Some 64 naturally occuring N-oxides representing pyrrolidine-piperidine-, pyrrolizidine-, quinolizidine-, tropane-, isoquinoline-, morphinane-, indole- and miscellaneous-type alkaloids are reviewed. These alkaloid N-oxides are additional to and, in the main, have been isolated since those described in a 1971 review. The earlier review dealt with some 56 naturally occurring N-oxides which represented mainly pyrrolizidine and indole types. The role of N-oxides in plants is discussed.