Insecticidal and Neuroblocking Activities in the American Cockroach(Periplaneta americana L.)of Mannich Bases of Nitromethylene Imidazolidine Neonicotinoids

摘要

The insecticidal and neuroblocking activities of Mannich bases prepared from chloronicotinyl-and chlorothiazolylmethyl-ni-tromethylenimidazolidines,known potent insecticides,were measured in American cockroaches.The concentrations needed to cause neuroblocking in excised central nerve cord of the insects(BC)were 100-140 muM,far higher than those,1.6-1.9 muM,for the starting compounds.However,the minimum lethal doses by injection(MLD)for the Mannich bases were 0.92-1.2nmol,not very different from the values,0.28-0.46 nmol,for the starting compounds.The half-life of the Mannich base decaying to the original molecule was 5.3 hr in a physiological solution,which also suggests the potential of Mannich bases as proinsecti-cides for nitromethylene molecules.