6-Hydroxy-7-isopropyl-1,1,4a-trimethyl-2,3,4,4a,10,10a-hexahydrophenanthren-9(1H)-one

The title compound, C20H28O2, commonly named Sugiol, is a natural oxygenated diterpene that we have isolated for the first time from a hexane extract of the fruits of Juniperus Oxycedrus L. Its X-ray crystal structure determination confirms an abietane skeleton which was predicted by spectroscopic analysis, mainly by H-1 and C-13 NMR. The cyclohexane ring adopts a flattened chair conformation, while the cyclohexene ring adopts an envelope conformation. The molecules are linked through O-H center dot center dot center dot O hydrogen bonds to form a zigzag chain extending parallel to the c axis.