Sythesis And Properties Of Biologically Active Pyrazole Derivatives

In the thesis, the development of the study of pyrazole derivatives was reviewed.In order to search novel pyrazole derivative pesticides, we designed and synthesized three series of new pyrazole compounds. Their structures were characterized by IR,'H NMR,MS spectroscopes, and partly confirmed by element analysis. Target compounds were illustrated as I , II ,111.During preparing these compounds,(4-chloro-)3-alkyl-l-methyl-5-pyrazole carboxylic acid was first converted to (4-chloro-)3-alkyl-l-methyl-5-pyrazole carboxylic chloride by thionyl chloride, then reacted with a-hydroxyl alkyl-phosphonates, a-aminoalkylphosphonates and heterocyclic amines. The reaction conditions are mild and the yields are good.In IR spectra, carbonyl(C=O) and phosphonyl (P=O) appeared as very strong absorbing peak at 1700cm"1 and 1250cm'1 or so respectively. In *H NMR spectra, that the free spin of P-O-C bond and C-C bond is blocked, can be observed, because of the big substituted group adjacent to P. In MS spectra, generally, fragmentation mainly occurs between carbonyl carbon and oxygen or carbonyl carbon and nitrogen.Preliminary bioassay showed that some of these compounds I and II have a higher fungicidal activity and herbicidal activity. Herbicidal activity of most of these compounds I and II reach to the grade of B. Among them, herbicidal activity of compounds Ia, Ic, Ie, If, Ig, Im, Io, Ip, IIIb reach to the grade of A. They can be further investigated as lead compounds.