Synthesis and antifungal activity of some new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones

Seven new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones 4a–g have been synthesized by the oxidation of 2-hydroxychalcone analogues of pyrazole 3a–g with hydrogen peroxide (H2O2) in KOH–MeOH by Algar Flynn Oymanda (AFO) reaction. The structures of the compounds 4 were established by the combined use of 1H NMR, IR and mass spectra. All the seven compounds were tested in vitro for their antifungal activity against three phytopathogenic fungi, namely Helminthosporium species, Fusarium oxysporum and Alternaria alternata. Five compounds 4a, 4b, 4c, 4e and 4f were associated with substantially higher antifungal activity than commercial antifungal compound Actidione (cycloheximide) against all three phytopathogenic fungi.

Graphical abstractSeven new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones 4a–g have been synthesized by the oxidation of 2-hydroxychalcone analogues of pyrazole 3a–g and tested in vitro for their antifungal activity against three phytopathogenic fungi, namely Helminthosporium sp., Fusarium oxysporum and Alternaria alternata.Figure optionsDownload full-size imageDownload as PowerPoint slide