Efficient Access to the Iboga Skeleton: Optimized Procedure to Obtain Voacangine from <i>Voacanga africana</i> Root Bark
Bruno González, Catherine Fagúndez, Alejandro Peixoto de Abreu Lima, Leopoldo Suescun, Diver Sellanes, Gustavo Seoane, Ignacio Carrera
Abstract
root bark as a precursor of the iboga scaffold. Using a direct acetone-based extraction procedure (0.5 kg of root bark), voacangine was isolated in ∼0.8% of root bark dried weight, while the major alkaloids isolated from the bark were identified as iboga-vobasinyl dimers (∼3.7%) such as voacamine and voacamidine. Since these alkaloids contain the voacangine moiety in their structure, the cleavage of the dimers was further optimized, affording an extra amount of voacangine in ∼50% isolated molar yield. In this manner, the total amount of voacangine obtained by application of the whole procedure to the plant material (extraction and dimer cleavage) could almost duplicate the content originally found in the root bark.