Synthesis of β-damascone derivatives with a lactone ring and their feeding deterrent activity against aphids and lesser mealworms

Abstract

Starting from β-damascone, six new lactones were obtained. The Claisen–Johnson rearrangement of allylic alcohol and halolactonization of γ,δ-unsaturated acid were the key steps of the presented synthesis. The structures of the new derivatives were determined by spectroscopic data. The antifeedant activity of β-damascone towards two insect species with different feeding habits and food preferences, i.e., the peach-potato aphid Myzus persicae (Sulz.) and lesser mealworm, Alphitobius diaperinus Panzer, was studied, as well as the biological consequences of structural modification of the starting substrate. The successive structural modifications of β-damascone that resulted in the greatest antifeedant activity towards M. persicae were the incorporation of a lactone moiety and concomitant presence of bromine in the side chain. All β-damascone derivatives with a lactone moiety deterred the feeding of adults and larvae of A. diaperinus. Halo-δ-lactones were more active than halo-γ-lactones, and A. diaperinus adults were more sensitive to the compounds studied than larvae.