Design,Synthesis,and Bioactivity Of Novel Pyrroles,Pyrimidines,and Aryl Oxime Ethers

As important pesticide active substances,pyrroles,pyrimidines,and aryl oxime ethers have broad application prospects in the field of pesticides,with biological activities such as insecticidal,acaricidal,and bactericidal activities.They can be used as research structures for molecular design in the creation of new pesticides.Based on the structure of Chlorfenapyr,26 new pyrrole compounds were synthesized using active substructure splicing method,using Tralopyril as the starting material through hydrolysis,substitution,and other reactions;based on the structure of Flufenerim,12 new pyrimidines were synthesized using intermediate derivatization method;based on the active structural units of oxime ethers in Fenpyroximate,13 novel aryl oxime ethers were synthesized through addition and substitution reactions.The three series of 51 new compounds synthesized in this paper were characterized and confirmed by ¹H NMR and ¹³C NMR,and some of them were confirmed by HRMS.The main research content of this paper is summarized as follows:（1）26 pyrrole compounds were designed and sythesized,and their insecticidal activity against Plutella xylostella,Spodoptera exigua Hiibner,and their acaricidal activity against Tetranychus cinnabarinus were tested,the results show that:At a concentration of 100 mg/L,the lethal rates of compounds X-6r and X-6z against Plutella xylostella and Spodoptera exigua Hiibner exceeded 90%,the LC₅₀of X-6r and X-6z against Plutella xylostella were 17.91 mg/L and 19.23 mg/L,and the LC₅₀of X-6r and X-6z against Spodoptera exigua Hiibner were 15.20 mg/L and 15.36 mg/L,which were lower than the insecticidal activities of the control agent Chlorfenapyr against Plutella xylostella and Spodoptera exigua Hiibner(LC₅₀were 2.15 mg/L and 2.21 mg/L);the lethal rate of compound X-6z against Tetranychus cinnabarinus at a concentration of 10mg/L was 65%,and the LC₅₀of compound X-6z against Tetranychus cinnabarinus was6.19 mg/L.The acaricidal activity of compound X-6z was higher than that of the control agent Propargite(LC₅₀:16.19 mg/L).According to the modification of Chlorfenapyr,the biological activity of the synthesized series of pyrroles has been significantly reduced,suggesting that trifluoromethyl is an important active group in the structure of Chlorfenapyr.（2）12 pyrimidine compounds were designed and sythesized,and their insecticidal activities against Plutella xylostella and Spodoptera exigua Hiibner,and their acaricidal activity against Tetranychus cinnabarinus,and their bactericidal activity against eight plant pathogens,including Rhizoctonia solani,Phytophthora capsici,and Pyricularia oryzae Cav.were tested,the test results show that:The lethal rates of compound Y-5c against Plutella xylostella and Spodoptera exigua Hiibner at a mass concentration of 100mg/L were 44%and 43%,respectively,while the lethal rates of Y-5l against Plutella xylostella and Spodoptera exigua Hiibner at a mass concentration of 100 mg/L were 43%and 42%,respectively,which were lower than those of the control agent Flufenerim;The lethal rates of compounds Y-5b and Y-5c against Tetranychus cinnabarinus at a concentration of 10 mg/L were 49%and 46%,which were higher than those of the control agent Propargite;at a concentration of 50 mg/L,the fungicidal activity of compound Y-5c against Rhizoctonia solani was 40%,the fungicidal activity of Y-5l against Fusarium graminearum was 47%,and the fungicidal activity of Y-5a against Bipolaris maydis was43%;according to the structure activity relationship analysis,it was found that the biological activities of pyrimidine amines and pyrimidine amides in the synthesized series of pyrimidine compounds were superior to those of pyrimidine ethers and pyrimidine esters,and（6-chloropyridin-3-yl）methyl and p-toloxybenzyl could be used as good active structures for exploration.（3）13 aryl oxime ether compounds were designed and sythesized,and their acaricidal activity against Tetranychus urticae,and their bactericidal activity against eight plant pathogens,including Rhizoctonia solani,Phytophthora capsici,and Pyricularia oryzae Cav.were tested,the test results show that:The lethal rates of compounds Z-4e,Z-4f,and Z-4h against Tetranychus urticae at a concentration of 100 mg/L were 93%,91%,and 95%,respectively,which were lower than those of the control agent Fenpyroximate but better than the control agent Propargite;at a concentration of 50 mg/L,the bactericidal activity of compound Z-4h against Rhizoctonia solani was 54%,the bactericidal activity of Z-4k against Pyricularia oryzae Cav.and Fusarium graminearum was 50%and 56%,respectively,and the bactericidal activity of Z-4m against Cercospora arachidicola Hori and Bipolaris maydis was 51%and 50%,respectively.Through structure activity relationship analysis,it was found that the acaricidal activity of the synthesized series of aryl oxime ethers with the amide group of 2,2-dimethylpropionylamino and 2,2-dimethylbutyrylamino was superior to that of acetylamino;compounds Z-4k and Z-4m containing dipropionamide exhibit good bactericidal activity against a variety of bacteria.