Nine new isoxuxuarine-type triterpene dimers from maytenus chuchuhuasca

Abstract

Nine new isoxuxuarine-type triterpene dimers, named isoxuxuarines Bβ (1), Bβ (2), 7,8-dihydro-B (3), Cβ (4), Cβ (5), 7,8-dihydro-Cβ (6), Dβ (7), Dβ (8), and 7,8-dihydro-Dβ (9), were isolated from the South American medicinal plant 'xuxua' (Maytenus chuchuhuasca). The structures were elucidated on the basis of several spectroscopic analyses, including 2D-NMR experiments, MS spectra, and CD spectral studies. The isolations and structure elucidations of the new triterpene dimers are presented, and a rationale for the divergent formation of the regiochemical and stereochemical isomers of triterpene dimers is discussed. © 2004 Verlag Helvetica Chimica Acta AG, Zürich.