RHOIPTELENYL ACETATE, A NEW PENTACYCLIC TRITERPENOID FROM FICUS-THUNBERGII

Rhoiptelenol, (2), isolated from Ficus thunbergii Maxim. (Moraceae), h as been reported as a triterpenoid component. The title compound, (1), whose molecular formula was shown by its high-resolution mass spectru m to be C32H52O2, was obtained from (2) by acetylation with Ac2O and p yridine. The structure of (1) was proved by NMR spectroscopy to be one of a rearranged ursane-type triterpenoid with five six-membered rings . We have described the conformation and geometry of (1) by an X-ray c rystallographic analysis and molecular-mechanics calculations.