Synthesis and insecticidal bioactivities of 2,3-dihydroimidazo[1,2-a]pyridin-5(1H)-one derivatives

Abstract A novel synthesis of 2,3-dihydroimidazo[1,2-a]pyridin-5(1 H )-one 4 and its derivatives were described. Preliminary bioassays showed that some of the target compounds exhibited excellent insecticidal activities against brown planthopper ( Nilaparvata lugens ), cowpea aphids ( Aphis craccivora ) ( 4 , 5a , 5c , 5g , 5h , 5j , 5r , 6b , 6e ) and carmine spider mite ( Tetranychus cinnabarinus ( 5f , 5s , 6a ) at 500 mg/L. Among them, compound 4 was still active against brown planthopper and cowpea aphids at 4 mg/L. The insecticidal activities were influenced by the types and position of the substituents, which provided guidance for the structure modifications.