1992 Volume 17 Issue 1 Pages 17-25
Fungicidal activity of N-phenylformamidoximes against Botrytis cinerea resistant to benzimidazole fungicides was analyzed quantitatively by using their physicochemical and structural parameters and regression analysis. The results showed that steric and electronic effects of substituents at the 4-position of the 3, 5-dichlorophenyl group are important for the fungicidal activity and the fungitoxic property in terms of negatively correlated crossresistance to benzimidazole fungicides. The effects of oxime O-substituents were expressed by steric and hydrophobic parameters in the analysis of compounds having a 3, 5-dichloro-4-propynyloxyphenyl group. Further analysis for a larger data set including variations in both substituents gave a regression equation, which indicates significant contribution of hydrophobic, steric and electronic properties to the fungicidal activity. For the steric effects, the optimum sizes of substituents were presented by regression equations. These results suggest that steric and electronic interactions are important for molecular recognition at the receptor and that transportation process to the active site effectively controls the biological response as expressed by hydrophobic parameters.
