Semisynthesis and Antifeedant Activity of New Derivatives of a Dihydro-β-Agarofuran from Parnassia wightiana

摘要

Five new derivatives (>2–>6) were semi-synthesized using compound >1, a dihydro-β-agarofuran sesquiterpene with C-2 ketone obtained from Parnassia wightiana, as the starting material by acylation, oxidation, reduction, esterification, and amination, respectively. Structures of >2–>6 were confirmed by 1D- and 2D-NMR and HR-ESI-MS spectra. In addition, antifeedant activities of these compounds (>1–>6) were tested against the 3rd-instar larvae of Mythimna separata. Antifeedant effects of compounds >2 and >4 were greater than the parent compound >1 whereas other compounds exhibited low to no feeding deterrent effects against third instar M. separata larvae in lab bioassays. Therefore, our results suggest that acylated and reduced derivatives at C-8 and C-2, respectively, of >1 may improve the antifeeding effect. This preliminary information will be useful in designing new insect control agents against M. separata and other important pests.