Abstract
A germacranolide, namely pertilide (I), mp 186-187°C (dec.), [α]20D+1.4°, C15H16O4, was isolated from the leaves of Pertya glabrescens SCH. BIP. (Compositae). I yielded the 4, 5-epoxide (IV) on peracid oxidation, and the 1(10), 3-dien-14-oic acid (III) on catalytic hydrogenation. Chemical and spectroscopic studies (especially NMDR experiments on I, III and IV) led to the proposal for I of the structure formulated as I (devoid of its stereochemistry) in Chart 1. The results of X-ray crystallographic analysis of I and its dibromide (VI) established the stereochemistry of I as [1(10)Z, 4E]-(3R, 7R, 8S)-germacra-1(10), 4, 11(13)-triene-12, 8 : 14, 3-diolide.
