Alsmaphorazines C-E, indole alkaloids from Alstonia pneumatophora

Three novel indole alkaloids, alsmaphorazines C (1)-E (3), were isolated from the leaves of Alstonia pneumatophora (Apocynaceae) and their structures were determined on the basis of the 2D NMR and MS spectral analyses. The absolute configurations of 1 and 3 were elucidated by applying a modified Mosher's method and CD spectral analysis. These alkaloids possessed novel ring skeletons containing an octahydropyrrolo[2,3-b]pyrrole unit.