QUANTITATIVE STRUCTURE-ACTIVITY STUDIES OF PYRETHROIDS .29. COMPARATIVE MOLECULAR-FIELD ANALYSIS (3-DIMENSIONAL) OF THE KNOCKDOWN ACTIVITY OF SUBSTITUTED BENZYL CHRYSANTHEMATES AND TETRAMETHRIN AND RELATED IMIDO- AND LACTAM-N-CARBINYL ESTERS

The relationship between structure and intrinsic knockdown potency against house flies, measured under synergistic conditions with metabolic inhibitors, was examined quantitatively for three series of chrysanthemic acid esters. The first series was tetramethrin and related N-methylol esters and the second and third were meta- and para-substituted benzyl esters, respectively. The three-dimensional quantitative structure-activity relationship was examined by comparative molecular field analysis (CoMFA). All three series of compounds could he analyzed by steric-field descriptor terms. For two of the three series, hydrophobicity improved the correlation when used as an additional variable. The results were consistent with our previous quantitative analyses done with free-energy-related substituent and submolecular parameters and the traditional regression procedure. Variations in the knockdown potency of all three series taken together, with their different skeletal structures of the alcohol moiety, could be analyzed by CoMFA with the steric- and electrostatic-field descriptor terms. The additional use of the hydrophobicity descriptor did not improve correlation for the combined set, perhaps because of multiple collinearity among the hydrophobicity parameter and steric- and electrostatic-field descriptors. © 1994 by Academic Press, Inc.