Abstract:
To discover lead compound with high antifungal activity, based on our previous studies, 18 novel 3-(difluoromethyl)-1-methyl pyrazole-4-carboxylic oxime esters were designed and synthesized based on the previous studies. Their structures were confirmed by
1H NMR,
13C NMR and HRMS. The configuration of oxime ester was confirmed to be
E by the X-ray single crystal diffraction of the compound
9g . The
in vitro bioassay results showed that the target compounds displayed antifungal activities against
Botrytis cinerea,
Valsa mali and
Gaeumannomyces graminis. Especially, the compound
9d showed excellent activity against
V. mali (EC
50 = 0.89 μg/mL) and
9r exhibited satisfied activity against
G. graminis (EC
50 = 3.34 μg/mL), which are better than or smilar to the lead compound
L1 (
E-2-chloro-6-fluorobenzaldehyde
O-(1-methyl-3-phenyl-1
H-pyrazole-5-carbonyl) oxime)
and trifloxystrobin.