Alkaloids of Vinca Species V: Structure Elucidation of Herbadine, an Alkaloid Isolated from Vinca Libanotica

Abstract

Herbadine, a novel dihydroindole alkaloid, was isolated from the aerial parts of Vinca libanotica Zucc. (Apocynaceae). The physical and spectral data (UV, IR, NMR, and mass spectroscopy) indicated the alkaloid to be a derivative of ajmaline. Comparative high‐resolution NMR studies with quebrachidine and high‐resolution mass spectral studies established the structure of the alkaloid to be 2‐epi‐3‐hydroxyquebrachidine. Herbadine was previously isolated from another species by Russian workers and a structure was postulated. The current paper gives evidence for a corrected structure of herbadine.