Tetra-hydro-alstonine.

In the title compound, C21H24N2O3 [systematic name: methyl (20α)-16,17-dide­hydro-19α-methyl-18-oxayohimban-16-carb­oxy­l­ate], the mol­ecule adopts an L-type conformation. The crystal packing is governed by one N—H⋯π and one C—H⋯π inter­actions. The crystal cohesion is ensured by inter­molecular van der Waals contacts [shortest O⋯O contact = 3.199 (2) A].