A class of 18(13 → 14)-abeo-schiartane skeleton nortriterpenoids from Schisandra propinqua var. propinqua

A class of C-29 triterpene dilactones (1-6) featuring 18(13 -> 14)-abeo-schiartane skeleton have been isolated from the stems of Schisandra propinqua var. propinqua. The structures of new compounds, propindilactones K-O (1-5), were determined on the basis of comprehensive spectroscopic means. Biogenetic pathway of 1-6 was proposed and then chemically mimicked. The absolute stereochemistries of new compounds were established on biosynthetic consideration coupled with CD experiments. Compound 2 showed promising anti-HBV activity in vitro. (C) 2008 Elsevier Ltd. All rights reserved.