(+/-)-Schefflone: a trimeric monoterpenoid from the root bark of Uvaria scheffleri.

The trimeric monoterpene and mildly mosquito larvicidal agent, (+/-)-schefflone, that is an apparent derivative of the antiparasitic aromatic monoterpene espintanol, was isolated from the antimalarial extracts of the root bark of Uvaria scheffleri, together with espintanol. Structural determination of (+/-)-schefflone was achieved from spectroscopic data and confirmed by single-crystal X-ray diffraction analysis. (+/-)-Schefflone can be considered a product of a non-enzymatic Diels-Alder-type cycloaddition reaction of the quinonemethide derivative of espintanol as the diene and dienophile.