Synthesis, characterization and biological activities of N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles

Ten novel N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles were synthesized by Claisen condensation of the aryl methyl ketones with ethyl nicotinate, the cyclization with hydrazine hydrate and the N-acylation with acyl chloride in turn. The structures of all the compounds synthesized were confirmed by means of Fourier transform infrared(FTIR), 1H NMR, mass spectroscopy and elemental analysis. The biological activities of the title compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles exhibited a certain degree of antibacterial and antifungal activities. Comparatively, compounds 3c and 3d exhibited much significant antibacterial and antifungal activities than the other pyrazole derivatives.