Structure-activity analysis of insecticidal organosila pyrethroid-like ethers against American cockroaches

The insecticidal activity of a set of injected dimethyl(substituted phenyl)silylmethyl meta-phenoxybenzyl ethers was measured against American cockroaches. The effects of aromatic substituents in the phenylsilyl moiety on the activity were position-specific. Substituents at the ortho and meta positions were unfavorable to the activity. Variations in the potency measured under conditions where the oxidative metabolic mechanism was inhibited were quantitatively analyzed using the physicochemical parameters of the aromatic substituents on the phenylsilyl moiety and molecular hydrophobicity. Variations in the potency were parabolically related to the hydrophobicity. The activity increased with the maximum width of the substituents