Schultz, K; Kaiser, R; Knudsen, JT

Flavour and Fragrance Journal [Flavour Fragrance J.], vol. 14, no. 3, pp. 185-190, Jun 1999

In continuation of our search for new or uncommon compounds in diverse natural scents we investigated the flower volatiles of Cyclanthus bipartitus Poit., a species of the neotropic family Cyclanthaceae. The structure of the main constituent, representing over 80% of the trapped headspace sample, was elucidated as (E)-2,6-dimethylnona-6,8-dien-4-one (1b), a derivative of the biologically highly interesting C sub(11)-homoterpene (E)-4,8-dimethylnona-1,3,7-triene (5). Because of the uniqueness of 1b to Cyclanthus bipartitus we suggest the name (E)-cyclanthone. Additionally, the respective Z-isomer (1a), the structurally related (E)-6,7-epoxy-2,6-dimethylnon-8-en-4-one (2) and (E)-2,6-dimethylnona-6,8-dien-4-ol (3) were identified as minor constituents. Proof of the new natural product structures was obtained by synthesis. The results of this investigation are considered in the light of the floral biology as well as the taxonomic status of Cyclanthus bipartitus.