New skeletal sesquiterpenoids, caprariolides A-D, from Capraria biflora and their insecticidal activity

Four structurally novel isomeric sesquiterpenes have been isolated from the aerial parts of Capraria biflora. Caprariolides A (1), B (2), C (3), and D (4); have been determined by NMR spectroscopy experiments to be the (3S,5S,9R), (3R,5S,9R), (3R,5R,9R), and (3S,5R,9R) isomers of 7-(furan-3'-yl)-3,9-dimethyl-1-oxaspiro[4.5]dec-6-en-2-one, respectively. Both 1 and 2 were found to exhibit insecticidal activity against adult Cylas formicarius elegantulus, one of the most destructive insect pests of the sweet potato,Ipomoea sp.