Synthesisandfungicidalactivityof<italic>N</italic>-(2-trifluoromethyl-4-chlorophenyl)-2-pyrazoleamidecyclohexylsulfonamides

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 EC₅₀ 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.