PLS Structure-Insecticidal Activity of Nitromethylene, Pyrrole- and Dihydropyrrole-Fused Neonicotinoids

Neonicotinoids are considered to be one of the important classes of insecticides used at the present time. In this study the partial least squares (PLS) approach is applied to a series of 25 nitromethylene, pyrrole- and dihydropyrrole-fused neonicotinoids to model their insecticidal activity against the cowpea aphids (Aphis craccivora). The neonicotinoid structures were optimized using molecular mechanics calculations (MMFF94s force field). Structural parameters calculated for the minimum energy conformers were related to the pLC₅₀ values. Linear modeling is performed using the PLS approach. A model having three components with good statistical results (R²X(Cum) = 0.963, R²Y(cum) = 0.870 and Q²(Cum) = 0.796) is obtained. Internal and external validation parameters were calculated to check the model validity. A robust PLS model with predictive power is obtained. It can be used for the prediction of new insecticides active against the cowpea aphids.