Structural determination of 3β,11β-dihydroxyfriedelane from Maytenus robusta (Celastraceae) by 1D and 2D NMR

Abstract

A new pentacyclic triterpene, 3β,11β-dihydroxyfriedelane was isolated from leaves of Maytenus robusta Reissek (Celastraceae) together with other four known compounds: 3-oxofriedelane (friedelin), 3β- hydroxyfriedelane, 3-oxo-29-hydroxyfriedelane and 3-oxo-11β- hydroxyfriedelane. The structure and chemical conformation of the new friedelane triterpene were established by 1H and 13C NMR, including the 2D experiments, HSQC, HMBC, COSY and NOESY.