THE SESQUITERPENE CONSTITUENTS OF THE LIVERWORT PREISSIA-QUADRATA

The labile sesquiterpene hydrocarbon germacrene C is the main constitu ent of a chemotype of the liverworth Preissia quadrata collected in So uthern Germany. Its temperature dependent rearrangement to racemic del ta-elemene is observed by capillary gas chromatography using cyclodext rins as chiral stationary phases. In addition, the rarely found ent-se squiterpenes (+)-germacrene D, (+)-trans-beta-caryophyllene, (+)-beta- caryophylleneoxide, (+)-cubebol and racemic alismol [1 beta,5 alpha-gu aia-6,10(15)-dien-4-ol] were identified as major constituents using sp ectroscopic methods and enantioselective gas chromatography. Minor con stituents are (+)-alpha-copaene, (+)-delta-selinene, (-)-delta-cadinen e, germacrene B and (-)-cascarilladiene (eudesma-5,7-diene). Copyright (C) 1996 Elsevier Science Ltd