Two racemic and two enantiomeric pairs of new δ-hydroxy-γ-lactones based on the p-menthane system were prepared from racemic and optically active cis- and trans-piperitols. The Johnson-Claisen rearrangement of the piperitols, epoxidation of the γδ-unsaturated esters, and acidic lactonization of the epoxy esters were described. The structures of the compounds were confirmed spectroscopically. The antifeedant activities of the hydroxy lactones and racemic piperitone were evaluated against three insect pests: lesser mealworm, Alphitobius diaperinus (Panzer); Colorado potato beetle, Leptinotarsa decemlineata (Say); and peach-potato aphid, Myzus persicae (Sulz.). The chemical transformation of piperitone by the introduction of a lactone moiety and a hydroxy group changed its antifeedant properties. Behavioral bioassays showed that the feeding deterrent activity depended on the insect species and the structure of the compounds. All hydroxy lactones deterred the settling of M. persicae. Among chewing insects, the highest sensitivity showed A. diaperinus adults.
两对消旋和两对手性的新δ-羟基-γ-内酯基于p-薄荷烷系统,分别由消旋和光学活性的顺式和反式薄荷醇制备而成。文中描述了薄荷醇的约翰逊-克莱森重排、γδ-不饱和酯的环氧化以及环氧酯的酸性内酯化过程。化合物的结构通过光谱学方法确认。研究了羟基内酯和消旋
薄荷酮对三种害虫的抗取食活性:小黄米虫(Alphitobius diaperinus,Panzer);科
罗拉多土豆甲虫(Leptinotarsa decemlineata,Say);以及桃-土豆蚜虫(Myzus persicae,Sulz.)。通过引入内酯基团和羟基对
薄荷酮进行的
化学转化改变了其抗取食特性。行为
生物测定表明,取食抑制活性依赖于昆虫种类和化合物的结构。所有羟基内酯都能抑制桃-土豆蚜虫的定居。在咀嚼昆虫中,小黄米虫成虫的敏感性最高。