Tirucallane, apotirucallane, and octanorapotirucallane Triterpenes of Simarouba amara

A chemical investigation of the bark of Simarouba amara, collected in Barbados, resulted in the isolation of six new triterpenes (3-8), in addition to two known compounds, 3-oxatirucalla-7, 24-dien-23-ol ( 1) and niloticin ( 2). Compound 3 is a tirucallane triterpene, while compounds 4-7 are apotirucallane derivatives containing an epsilon-lactone in ring A. Compounds 6 and 7 were obtained as a mixture that could not be separated, while compound 8 is an octanorapotirucallane derivative that lacks the C-8 side chain. The structures of all compounds were determined by interpretation of physical data.