Synthesis And Insecticidal Activity Of 1, 1-Dichloropropenyl Derivatives

Chemical pesticides are widely used in agriculture, forestry and hygienic pest controlling. As the development of new pesticides lags far behind the rate of elimination of the old ones through selection, while the speed that most insects generate resistance exceeds the pace of development of new safe efficient insecticides, a novel compound with new target and mode of action is need badly, especially used to control resistant species. Pyridalyl meets the needs exactly. It shows good safety and selectivity, particularly excellent activity against existing resistant insects and a different mode of action from other existing insecticides. As its indispensable bioactive group is 1,1-dichloropropenyl, design and synthesis of 1,1-dichloropropenyl derivatives, especially analogs of pyridalyl are given much attention widely and researched deeply.To improve the physical characteristics and produce higher activities, we hybriddized the structures of 1,1-dichloropropenyl and some known highly bioactive group existing in natural product such as coumarin, chalcone, benzothiazole, benzoxazole, aldehydeoximeandα,β-unsaturated ketoxime. Some bioactive moieties, such as oxadiazole, triazolopyrimidine, chromone and strobilurin, were also introduced as substitutes according to the principle of combination of bioactive substructure. We combined substituted sulphydryl heterocyclic containing nitrogen and 1,1-dichloropropenyl directly for the first time, to generate a new skeleton with insecticidal activity. These structures of the title compounds were characterized by ~1H NMR, GC-MS spectroscopies, elemental analysis and X-ray diffraction analysis. The structures of the five series compounds are summarized as follows:The results of biological assay indicated that most of the title compounds did not exhibit significant insecticidal activity, however. The compounds i-f and i-g exhibited an 65 and 30% inhibition effect at a concentration of 100ppm against Spodoptera litura, respectively, which showed that electron-withdrawing group was favored for insecticidal activity. While Ar was benzothiazole or benzoxazole, it didn't matter whether electronwithdrawing group or electron-donating group, but CLogP between 7 and 9 with the activity against Plutella xylostella. Disappointedly, series ii and iii did not show any insecticidal activity. As to series iv, the favored heterocycle is benzoxazole, but disfavored one containing chloride. Besides, The compounds both iv-f and iv-i exhibited an 100% inhibition effect at a concentration of 500ppm against Aphis medicagini, which prompted us to further modify the frame construction to generate the series v. However, the series v did not show insecticidal activity. The analogs of pyridalyl can be designed according to its CLogP value. The thesis provides bases to do structural modifications and discover some highly insecticidal compounds.