Synthesis And Insecticidal Activities Of Novel Bifenthrin Pyrethroids

Bifenthrin（3-[（1Z）-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarbo-xylic acid（2-methylbiphenyl-3-yl）methyl ester is an important active ingredient of a new kind of pyrethroid,with low toxicity and low residue.However,overuse of pyrethroid insecticides has brought about some serious ecological problems,such as high-level resistance and fish toxicity.Thus,it is necessary to find alternative products to overcome the above problems.A series of novel bifenthrin derivatives are designed and synthesized to enhance the anti-mosquito activity in this thesis.2-chloro-3-iodobenzenemethanol was synthesized by carboxylation,acylation,esterification,reduction with 1-chloro-2-iodobenzene as the parent.And then,esterification of 2-chloro-3-iodobenzenemethanol with 3-（2,2-dibromoethenyl）-2,2-dimethylcyclopropanecarboxylic acid（commonly known as dibromo-chrysanthemic acid）,generating compound 5[3-iodo-2chlorophenyl 3-（2,2-dibromovinyl）-2,2-dimethylcyclopropanecarboxylate].Lastly,compound 05 is Suzuki cross-coupled with the corresponding aryl boronic acid to form a new bifenthrin derivative.The optimization conditions are as follows:1）Selection of synthesis route:Priority esterification can improve the success rate of reaction and reduce the occurrence of side reactions2)Optimization of coupling reactions:Solvents,alkali and catalysis all affect the yield of the reaction.The best way to do that is using toluene as a solvent,adding potassium phosphate,adding a catalyst[1,1-bis（diphenylphosphino）ferrocene]palladium dichloride,and then adding The corresponding aromatic boronic acid was reacted at 80°C for 8 hours.After a series of post-treatments,the corresponding novel bifenthrin is obtained in a yield of30%to 80%.all the compounds synthesized were characterized by ¹H NMR,¹³C NMR,HRMS.Novel bifenthrin pyrethroids analogues have been designed and synthesized on the basis of commercial pesticides.17 analogues containing halogenated phenyl or pyridyl were obtained and their biological activity was evaluated,include larvae and adult mosquito of sensitivity Aedes albopictus.Insecticidal activity results indicated that most compounds,especially compounds containing pyridyl group,exhibited better antimosquito activity against larvae.And some compounds,such as compound 05,06,07,17,18,19,22 showed better insecticidal activity with bifenthrin.The activity of compound 06,17,22 on adult mosquitoes was also betterr than bifenthrin.In addition,Resistance testing of aedes albopictus in the wild,the acute cytotoxicity of SH-SY5Y cells and photostability of compounds all those experiments have proved that it is meaningful to synthesize these compounds.