Asymmetric Chloronicotinyl Insecticide , 1 - [ 1 - ( 6 - Chloro - 3 - pyridyl ) ethyll - 2 - nitroiminoimidazolidine : Preparation , Resolution and Biological Activities toward Insects and Their Nerve Preparations

prepared, and the absolute configurations of the enantiomers were determined by an X-ray analysis. The insecticidal activity against the housefly measured with metabolic inhibitors showed the (S) enantiomer to be slightly more active than the (R) isomer. ElectrophysioIogical measurements o" the American cockroach central nerve cord showed the compounds to elicite the impulses and subseqttently blocked them. The neuroblocking potency of the (S) isomer was 5.9 "M, while that of the (R) isomer was as high as 73 geM. The molar conce"trations required for 50% inhibition of the specific