苯基吡唑类化合物的合成、杀虫活性及对蜜蜂的毒性

Synthesis,insecticidal activity and toxicity to bees of phenylpyrazoles

【目的】以氟虫腈结构为骨架,寻找具有杀虫活性和对环境友好型的苯基吡唑类化合物。【方法】以不同取代基的苯胺为原料,经2步法合成含有不同取代基的苯基吡唑类化合物1~21;产物结构经1H NMR、13C NMR和ESI-MS分析确定;采用浸液法测定目标产物对小菜蛾Plutella xylostella的生物活性;测定化合物1、5、12和16对中华蜂Apis cerana的急性经口毒性。【结果】化合物1、5、12和16处理小菜蛾24 h的LC50分别为0.26、0.95、0.33和1.10 mg·L^-1,其中化合物1和12对小菜蛾的活性优于氟虫腈。化合物5、12和16对中华蜂的急性经口毒性比氟虫腈(0.05 mg·L^-1)低,但仍属于剧毒,LC50分别为0.21、0.22和0.09 mg·L^-1。构效关系表明,苯环的取代基对苯基吡唑类化合物的活性影响很大,当苯环邻位存在—Cl或—Br、对位为—Cl、—CF3或—OCF3时,化合物对小菜蛾表现出极好的活性。【结论】氟虫腈苯环取代基的替换可以提高对小菜蛾的生物活性、降低对中华蜂的毒性,研究结果对今后芳基吡唑类杀虫剂开发、结构优化具有一定的指导意义。

【Objective】To obtain phenylpyrazoles which have insecticidal activities and are eco-friendly based on fipronil framework.【Method】Using anilines with different substituents as materials,phenylpyrazole compounds 1-21 with different substituents were synthesized in two steps.The product structures were confirmed by 1H NMR,13C NMR and ESI-MS analysis.The biological activities of target products against Plutella xylostella were determined by leaf immersion method.Acute oral toxicities of compounds 1,5,12,and 16 to Apis cerana were determined.【Result】After 24 h treatment,LC50 of compounds 1,5,12,16 against P.xylostella were 0.26,0.95,0.33 and 1.10 mg·L^-1 respectively.The activities of compounds 1 and 12 against P.xylostella were higher than that of fipronil.Compounds 5,12 and 16 showed lower acute oral toxicities to A.cerana compared with fipronil(0.05 mg·L^-1),but still were highly toxic with LC50 of 0.21,0.22 and 0.09 mg·L^-1 respectively.The structure-activity relationship indicated that the substituent of the phenyl-ring had a great influence on the activity of the phenylpyrazole compound.When the ortho position of the benzene ring was—Cl or—Br,the para position was—Cl,—CF3 or—OCF3,the compound had excellent activity against P.xylostella.【Conclusion】Replacement of substituents on the phenyl-ring of fipronil can improve the biological activity against P.xylostella,and reduce the toxicity to A.cerana,which has certain guiding significance for the development and structural optimization of arylpyrazole insecticides in the future.