Thermal rearrangement of harunganin and allylations of some compounds from Harungana madagascariensis

Abstract

The thermal rearrangement of harunganin (1), a major constituent of Harungana madagascariensis, was investigated. The rearranged products are mostly found as natural constituents in this plant. In addition, allylations of some anthranoids including harunganin (1), harongin anthrone (8), harunganol B (9), kenganthranol A (10) and 1,7-dihydroxyxanthone (14) with allyl bromide in the presence of potassium carbonate were studied. The chelated phenolic hydroxyl groups were not allylated under theses conditions. Harongin anthrone (8) and harunganol B (9) gave the O- and C-bisallylation products 11 and 12, respectively. ©ARKAT USA, Inc.