Abstract:
Pyrazolecarboxamide derivatives have attracted much attention in the field of agrochemical discovery. With the objective of exploring the novel fungicides, 14 novel
N-(2-trifluoromethyl-4-chlorophenyl)-2-pyrazoleamide cyclohexylsulfonamides were obtained by amidation method using EDCI/HOBt. Their structures were characterized by
1H NMR,
13C NMR, MS and elemental analysis. The crystal structure and stereo configuration of compound
3g were determined by X-ray diffraction. The bioactivities against
Botrytis cinerea revealed that the synthesized compounds possessed good fungicidal activities. The bioactivities determined by the mycelium growth rate method showed that the EC
50 values of compounds
3a ,
3e and
3j were 4.28, 10.08 and 11.31 mg/L, respectively, and the activities were lower compared with the positive controls, namely boscalid and procymidone. However, 7 compounds with the inhibition rates against spore germination of more than 85% showed better activities compared to the positive controls. The further
in vivo bioassay showed that compound
3e exhibited better control effect (the control effect is 77.5% with tomato leaves and 65.2% with the flowers st the application concentration of 200 mg/L) than the commercial fungicides, which could be used as lead compounds for further study.