Trijugins A and B, tetranortriterpenoids with a novel rearranged carbon skeleton from Heyneatrijuga (Meliaceae)

Abstract

Two new tetranortriterpenoids, trijugins A (1) and B (3), isolated from the leaves of Heyneatrijuga (Meliaceae), have been shown to be derivatives of methyl angolensate but with a novel carbon skeleton having a contracted ring C. The structures were assigned on the basis of detailed 1H and 13C nuclear magnetic resonance spectroscopic examination including 2D long-range δC/δH correlation and homonuclear 1H nuclear Overhauser effect difference experiments.