Chemical studies on the annonaceae. Part 9. Indolosesquiterpene and aporphine alkaloids from Greenwayodendron(Polyalthia)suaveolens stem bark. X-Ray crystal stucture of greenwayodendrin-3-one

Abstract

The isolation and characterization of ten alkaloids, viz. five indolosesquiterpenes and five aporphines, and the triterpene polycarpol from the stem bark of G. suaveolens are reported. Four of the indolosesquiterpenes are shown, largely on the basis of ¹H- and ¹³C-n.m.r., to be based on the novel 1,3,4,4aα,5,6,6a, 13,13aα,13b-decahydro-4,4,6aβ,13bβ-tetramethyl-2H-benz[e]indolo[1,2-a]indole system (1) to which we have assigned the trivial name greenwayodendrine. The structure of one of the novel alkaloids is confirmed as greenwayodendrin-3-one (2) by X-ray crystallography, and by chemical interconversions the other three are identified as the 3α-hydroxy-(5), 3β-hydroxy-(4), and 3β-acetoxy-(3) derivatives.