CIS-DIHYDROAGAROFURAN FROM PROSTANTHERA SP AFF OVALIFOLIA

Steam distillation of the leaf and terminal branchlets of Prostanthera sp. aff. ovalifolia growing in northeastern New South Wales give 1-3% volatile oil containing 1,8-cineole, p-cymene, kessane and a novel C1 5H26O sesquiterpene. The latter gave (+)-delta-selinene on treatment w ith trimethyliodosilane. COSY, FLOCK and NOE difference NMR experiment s indicated cis-dihydroagarofuran. Infraspecific oscillation between k essane and cis-dihydroagarofuran as major component in Prostanthera wa s noted and hedycaryol proposed as a plausible common precursor.