Abstract:
Using antifungal medication econazole as the lead compound, a series of 1-2-benzyloxy-2-(2,4-difluorophenyl) ethyl-1
H-1,2,4-triazole derivatives were designed, synthesized, and characterized by
1H NMR,
13C NMR and HRMS. The
in vitro fungicidal activities of those compounds against 7 plant pathogenic fungi were evaluated to discover effective compounds preliminarily. The efficiencies of the most effective compounds were further tested against rice sheath blight and wheat stripe rust in greenhouse and field. Furthermore, the inhibitory effect on the ergosterol biosynthesis of
R. solani also were determined. Most of the target compounds exhibited good fungicidal activities against the tested plant pathogenic fungi
in vitro, especially against
Rhizoctonia solani and
Alternaria solani. By measuring their EC
50 values, it was found that the EC
50 values of the tested compounds against
R. solani were less than 3 μmol/L, which were significantly higher than those of difenoconazole and econazole. The EC
50 values of
4a ,
4b ,
4c ,
4g ,
4i and
4l against
A. solani were all lower than 10 μmol/L. Compounds
4b and
4i showed higher than 70% control efficiencies against wheat stripe rust at 250 μmol/L in greenhouse. And the control efficiency of compound
4b against wheat stripe rust was 81.93% at 240 g a.i./hm
2 in field. In addition, compounds
4b and
4i were found to be effective in inhibiting ergosterol biosynthesis of
R. solani with the inhibition rate of around 80% at the concentration of 100 μmol/L.