Trijugins <i>A</i> and <i>B</i>, tetranortriterpenoids with a novel rearranged carbon skeleton from <i>Heynea</i><i>trijuga</i> (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 1 H and 13 C nuclear magnetic resonance spectroscopic examination including 2D long-range δ C /δ H correlation and homonuclear 1 H nuclear Overhauser effect difference experiments.