11 β,12 β-Diacetoxyharrisonin, a tetranortriterpenoid from Harrisonia abyssinica

A new tetranortriterpenoid, 11 β,12 β-diacetoxyharrisonin, together with the known atalantolide, obacunone, harrisonin, 12 β-acetoxyharrisonin, pedonin, cneorin R and perforaquassin A have been isolated from the root bark of Harrisonia abyssinica. The structure of the new compound which is based on a rearranged tetranortriterpenoid with a five membered ring-B and a seco ring-A and D was assigned on the basis of extensive NMR studies and X-ray diffraction analysis. In addition, the structure and relative configuration of the known perforaquassin A was confirmed by X-ray diffraction analysis.