Study On Synthesis And Biological Activity Of Pyrazolecarboxamide Derivatives

Since the 1980s, pesticide research and development have entered a full new stage, and the efficient, low toxicity, environment friendly have become the new trend. As an important part of modern pesticides, fungicides are playing an irreplaceable role in plant protection and crop production. Pyrazolecarboxamides are widely used in the field of medicine and pesticides, which often showed high efficiency and broad-spectrum biological activity for its pyrazolyl and amide group. The pesticide Penthiopyrad launched by Mitsui, Furametpyr launched by Sumitomo, and the pesticide Isopyrazam, Sedaxane both recently launched by Syngenta are the commercialized representatives. In addition, the four different positions of the pyrazole ring make the carboxamides has structural diversity and a variety of bioactivities, which is also a cause for concern.In order to create new and high-efficient pyrazolecarboxamide fungicides, this paper combining the structural characteristics of commercially pesticides Furamtpyr and Penthiopy- pyrad and according to substructure linking method, a series of pyrazole-4-carboxamide derivatives was synthesized by the reaction of 3-difluoromethyl-1-methyl-1H-pyrazole-4-car- boxylic acid with various amines, of which 31 derivatives are first studied. The structures of these compounds were confirmed by IR, 1H-NMR, and MS.The preliminary biological activities of the target compounds were tested, and the result indicated that all compounds showed different inhibitory activites against Fusarium graminer- um, Fusarium oxysporum vasinfectum, Pyricularia grisea, Botrytis cinerea, Colletotrichum gloeosporioides and Altermaria sonali at the concentration of 100 mg/L. The compounds of G series exhibited excellent bactriostasis, some compounds has a higher rate of inhibition and better control effect than the positive control Azoxystrobin. Thebactriostasisof compound La and Lc against Botrytis cinerea was up to 87.1% and 73.5% separately; the inhibition rate of Ha against Botrytis cinerea, Colletotrichum gloeosporioides, and Fusarium graminrum was 79%, 77% and 88.2% separately; and Hb against Botrytis cinerea and Colletotrichum gloeosporioides was 87.5% and 73.5% separately.