The Discovery of Bifenazate, a Novel Carbazate Acaricide

A history of the discovery of the novel carbazate acaricide, bifenazate, is outlined. When a novel ortho-biphenyl substituted hydrazide compound showed acaricidal activity in the pesticide discovery screen, a small number of analogs were made to confirm and explore acaricidal effects. An ortho-biphenylcarbazate analog gave significantly greater acaricidal activity. Thereafter, several hundred structurally-diverse biphenyl-substituted carbazate analogs were synthesized and evaluated in a bioassay with the two-spotted spider mite (Tetranychus urticae Koch) in order to optimize the acaricidal activity. As a result of the optimization process, bifenazate, the analog with a methoxybiphenyl substituent to the terminal nitrogen atom of isopropyl carbazate, was selected for development and registration.