Quantitative structure-activity relationships of insecticidal diphenyldichlorocyclopropanes

Neurophysiological activity of a series of aromatic-substituted 1,1-diphenyl-2,2-dichlorocyclopropanes (DCC analogs) in the induction of repetitive discharges in excised central nerve cords of the American cockroach was determined by an extracellular recording technique. Quantitative analysis using physicochemical parameters showed that variations in the activity were parabolically correlated with the van der Waals volume of aromatic substituents. Insecticidal activity of these compounds in the American cockroach under conditions where oxidative metabolic activity was inhibited by piperonyl butoxide was also determined. This was related to the repetitive nerve discharge activity, when transport factors were separated by using a hydrophobicity parameter. The analyses showed that the aromatic substituent effects on the neurophysiological activity as well as the relationship between insecticidal and neurophysiological activities are very close to those observed previously for DDT analogs including DDT, DDD, and prolan derivatives.