(1R,6aS)-3aβ,4,5,6,7,8,9,9a-Octahydro-9aβ-methyl-1H-1,6a-ethanopyrido[2,1,6-de]quinolizine

This low-melting crystalline base is the major alkaloid of Poranthera coryrnbosa. Unlike the accompanying bases in the alkaloidal extract, it is dextrorotatory with [exlD + 29° (c 0.35, CHC13). It possesses a tetracyclic structure and contains only a methyl group as a substituent.

Denne et al., Tetrahedron Lett., 3107 (1971)