Conformational study of 3β,16β-dihydroxyfriedelane by NMR and ab initio calculations

Abstract

The complete chemical shift assignments of 3β,16β-dihydroxyfriedelane, a natural compound isolated from the hexane extract of Maytenus acanthophylla leaves was achieved through 1D/2D NMR spectral data. Combining ab initio Hartree-Fock [HF/6-31G(d)] and Density Functional Theory [DFT/B3LYP/6-31G(d,p)] calculations with NMR spectral data, it was possible to establish the predominance of the chair-chair-chair-boat-boat conformation for the five six-membered ring systems in this pentacyclic triterpene.