Synthetic Pyrazole Derivatives as Growth Inhibitors of Some Phytopathogenic Fungi

Abstract

The present study was carried out to investigate the antifungal activity of pyrazole/isoxazole-3-carboxamido-4-carboxylic acids, 4-oxo-5-substituted pyrazolo[3,4-d]pyrimidine-6-thiones, and N-alkyl/aryl-N'-(4-carbethoxy-3-pyrazolyl)thioureas against Pythium ultimum, Botrytis cinerea, and Magnaporthe grisea. The results on growth inhibition showed differences in the sensitivity of the three fungi to the tested substances, and in general P. ultimum was shown to be the most sensitive. On all phytopathogens the best results within the pyrazole/isoxazolecarboxamide series are given by the compounds with the carboxamide and carboxylic groups in positions 3 and 4; the presence of these groups seems to be critical for biological activity in this series of compounds. Among the pyrazolopyrimidines the derivative supplied with the benzylic group was the most active on the three fungi and in particular against P. ultimum. Several compounds belonging to the thiourea series are able to inhibit selectively M. grisea at 50 and 10 microg mL(-1), doses at which the reference commercial compound tricyclazole had low or no effect.

2-(5-Chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-6-(4-nitrophen­yl)-4-phenyl-1,3-diazabicyclo[3.1.0]hex-3-ene

“…Pyrazoles and their derivatives have been known to exhibit a wide range of physiological and pharmacological activities, such as anti-inflammatory [38], antibacterial [39,40], anti-convulsant [41], anticancer [42,43], anti-depressant [44], anti-hyperglycemic [45], antiviral [46], antipyretic [47], antioxidant [48], antitubercular [49], fungicides [50], and analgesic activities [51]. These heterocycles have also found applications in transition-metal chemistry as an analytical reagent [52], ligand used for complexation with metals and as antioxidant additives to fuels [53,54].…”

4-(4-Chloro-5-methyl-3-trifluoromethyl-1H-pyrazol-1-yl)-6-(prop-2-ynyloxy)pyrimidine

“…For the applications of pyrazole derivatives, see: Hirai et al (2002); Krishnaiah et al (2002); Ohno et al (2004); Li et al (2008); Shiga et al (2003); Vicentini et al (2007).…”

“…There is much agrochemical interest in pyrazole derivatives because of their excellent bioactivity (Krishnaiah et al, 2002;Ohno et al, 2004;Li et al, 2008Shiga et al, 2003Vicentini et al, 2007). Numerous herbicides such as pyrazolate, pyrazoxyfen, benzofenap, pyraflufen-ethyl, fluazolate and pyrazosulfuron-ethyl with pyrazole moieties were commercialized (Hirai et al, 2002).…”

Novel directed synthesis of functionalized pyrazole derivatives via regioselective solvent-free thiylation of 3-alkenylpyrazoles with arenethiols

“…They are widely used as agrochemicals. [11][12][13][14] Pyrazole derivatives exhibiting acaricidal action and applied in modern practical disinfection and decontamination are of special importance. [15][16][17] In recent years, increasing interest has been focused on polypyrazole constructs which are promising ligands.…”