Rational design of insecticides.

A steric model of diaryl insecticides, which includes the structure of DDT and its analogues, was used for the synthesis of new highly active insecticides. The new compounds show low toxicity to mammals and their insecticidal activity can be potentiated by microsomal oxidase inhibitors. There is evidence that they readily undergo biological degradation. However, a spontaneous controlled chemical degradation was also established for the diaryl oxetanes, which form one group of a new series of insecticides. The theoretical model was further investigated using X-ray crystallography to establish one accurate structure. Biologically, the model is supported by studies of the correlation between insect mortalities and temperature and by measurements of nerve impulses at fly chemoreceptors after treatment with selected compounds.