Synthesis And Bioactivity Of 1,3,4-oxadiazole And Trifluormethylpyridyl Acrylonitrile Derivatives

1,3,4-oxadiazole insecticides have a unique mechanism of action,low toxicity,high efficacy,low residue and safety for non-target organisms.It is a hot topic in the field of pesticides,which is characterized by various changes in the positions of oxygen and nitrogen atoms and easy structural modification.The acrylonitrile structure is an excellent reactive group,which has the characteristics of alcohol-ketone interconversion in its molecular structure and is easy to be spliced by reactive groups.Therefore,acrylonitrile insecticides and acaricides has become one of the important directions in the creation of new pesticides.In this paper,the method of bioelectronic isosteric principle and active substructure splicing was used to synthesize seventeen new 1,3,4-oxadiazole derivatives by two-step nucleophilic substitution reaction and solid phosgene ring reaction,with metoxadiazone as a lead compound,2,3-dichloropyridine and 2,3-dichloro-5-trifluoromethylpyridine as the raw material.With cyenopyrafen and SPY-9625 as lead compounds,2,3-dichloro-5-trifluoromethylpyridine as the raw material,sixteen new trifluoromethylpyridyl acrylonitrile derivatives were synthesized by substitution,deesterification and addition reaction.The structure of the compounds were determined by means of ~1H NMR and HRMS.The insecticidal and acaricidal activity of the target compounds were tested according to the pesticide bioassay experimental criteria.Through biological activity tests,among the seventeen 1,3,4-oxadiazole derivatives,compounds II6k,II6l,III6a,III6b,III6c and III6d at the concentration of 50 mg/L had 100%lethality to Plutella xylostella.At the concentration of 2.5 mg/L,the lethality rate of compounds II6k and II6c against Plutella xylostella was higher than 80%.These compounds had good bioactivity,but the control effect to Tetranychus cinnabar was general.Among 16 trifluoromethylpyridyl acrylonitrile derivatives,compounds VI7b at the concentration of 5 mg/L had 100%lethality to eggs of Tetranychus cinnabarinus.At the concentration of 1 mg/L,the lethality rate against eggs of Tetranychus cinnabarinus was 89.6%.The series of compounds have certain activities of killing the Plutella xylostella,but the effect is not outstanding.