Norcyperone, a novel skeleton norsesquiterpene from Cyperus rotundus L

A novel norsesquiterpene, named norcyperone (1), and three known compounds: (-)-clovane-2,9-diol (2), rosenonolactone (3), and 5 alpha,8 alpha-epidioxy-(20S,22E,24R)-ergosta-6,22-dien-3beta-ol (4) were isolated from the rhizomes of Cyperus rotundus L. The structure of 1 was elucidated as 8,11,11-trimethylbicyclo5.3.1]undecane-5 alpha, 8 alpha-epoxy-3-one on the basis of extensive spectroscopic analyses, including 1D- and 2D-NMR, MS experiments, and single-crystal X-ray diffraction. This is the first report of a 8,11,11-trimethyl- bicyclo5.3.1]undecane-3-one type norsesquiterpene with a tetrahydrofuran ring at C-5 and C-8.