Synthesis and insecticidal activity of novel N-oxydihydropyrrole derivatives with a substituted spirocyclohexyl group

A series of 5-spirocyclohexyl-3-(2,6-dimethylphenyl)-1,5-dihydro-2H-pyrrol-2-one derivatives (3) with various substituents on the spirocyclohexyl ring was synthesized and evaluated for its insecticidal activity against the aphid, Myzus persicae. Substituents at the 1- and 4-positions of the dihydropyrrole ring were also varied to optimize the activity. An investigation of the structure-activity relationship revealed that methoxy, alkoxyalkoxy, ethylenedioxy and methoxyimino groups were favorable as substituents at the 4-position of the spirocyclohexyl ring. The activity was optimized by the respective substitution of a methoxy or methoxymethoxy moiety and cyclopropylcarbonyloxy group at the 1- and 4-positions of the dihydropyrrole ring.