Use of linear free energy related and other parameters in the study of fungicidal selectivity

Abstract

AbstractThe modulation of fungicidal activity in a congeneric series of compounds is dependent on several processes taking place in the biological object which may be influenced by the different hydrophobic, electronic and steric properties of the members of the series. These possible influences can be studied in a quantitative way with multiple regression analysis using substituent constants for the properties mentioned. The comparative study of the resulting regression equations for the activity on different fungi or on a fungus and another biological subject may contribute to an understanding of fungicidal selectivity. This is illustrated in studies on the fungitoxicity of isophthalonitriles, 2‐chlorobenzonitriles, arylsulphonyl‐ and arylsulphinyl‐alkylthio‐cyanates, acetylenic sulphones, methyl benzimidazol‐2‐ylcarbamates and phosphorus compounds derived from 3‐amino‐1,2,4‐triazole. In these studies new steric parameters were used, which have been introduced recently.