Structure-Activity Relationships of Vinyl Triazole Fungicides

Four types of vinyl triazole derivatives, (Z)- and (E)-4, 4-dimethyl-l-phenyl-2-(1, 2, 4-triazol-1-y1)-1-penten-3-ones, (Z)- and (E)-4, 4-dimethyl-1-phenyl-2-(1, 2, 4-triazol-1-y1)-1-penten-3-ols have been prepared and their fungicidal activities were determined. The alcohol analogs showed high protective activities against powdery mildew on barley (Erysiphe graminis), and brown rust on wheat (Puccinia recondita) in pot tests. Both of the ketone analogs with Z and E geometrical configurations were less active, but both of the alcohol analogs showed high activities. The activities of the E-alcohol analogs against both diseases were the highest. The E-alcohol analogs also showed excellent systemic activities and broad fungitoxic spectra. Such halogen substituents on the phenyl ring as 4-Cl, 2, 4-Cl2 and 2-F, 4-Cl of the E-alchohol analogs were favorable to the higher protective activities.