Structure and Absolute Stereochemistry of Nortriterpenoids from Schisandra chinensis (Turcz.) Baill

A varierty of previously unreported compounds, the cagelike hexacyclic schicagenin-type nortriterpenoid 1, three pre-schisanartane-type nortriterpenoids 24, seven C29 nortriterpenoids 511 possessing an uncommon pentacyclic carbon skeleton characterized by a 5/5/7/7/5 fused-ring motif bearing a C9 side chain, two highly oxygenated C28 nortriterpenoids 12 and 13 containing an unprecedented 5/5/7 ring nucleus bearing a C15 side chain, and the known C29 nortriterpenoid 14 were isolated from the leaves and stems of the Chinese medicinal plant Schisandra chinensis. The structures of these new metabolites were elucidated by means of detailed spectroscopic analysis. The absolute configurations of 4 and 5 were determined by time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculations, allowing the assignment of the absolute configurations of analogous compounds 13 and 613.