Macrocarpamine, a new bisindole alkaloid from Alstonia macrophylla WALL. A new bisindole alkaloid give the name (−)‐macrocarpamine (3) was isolated from the bark of Alstonia macrophylla WALL. Under pyrolytic conditions 3 is cleaved into the two known bases (+)‐pleiocarpamine (2) and (−)‐anhydro macrosalhin‐methin (5) Scheme 1. The structure of 3 (including relative configuration) was deduced on the basis of chemical evidence and from its UV.‐, IR.‐, NMR.‐ and mass spectroscopic data. Copyright © 1978 Verlag GmbH & Co. KGaA, Weinheim