Alkaloids of aristotelia species

A detailed phytochemical examination of the alkaloid content of two species of the family Elaeocarpaceae - Aristotelia serrata W.R.B. Oliver and Aristotelia fruticosa Hook F. - has been undertaken. A new group of indole alkaloids has been isolated from the abovementioned species. Of the sixteen bases obtained, one had been described previously and was reisolated from Aristotelia serrata. Spectroscopic and chemical evidence for the structures of the fifteen new minor alkaloids are presented. X-ray crystallographic studies confirmed the structures of two of them, and established the relative stereochemistries. In one case, the structural assignment was confirmed by synthesis. The absolute stereochemistries of altogether six alkaloids have been established through chemical correlations. A possible biosynthetic scheme for the Aristotaia alkaloids is presented. A preliminary investigation of one species of the family Menispermaceae - Pachygone vieillardii - has been made, and the results appear in Appendix-l. Of the five alkaloids isolated from this species, one appears to have a bisbenzylisoquinoline type of structure. Tentative evidence is presented to support a proaporphine-type structure for two further alkaloids, and a morphinane-type structure for each of the remaining pair of alkaloids.