Synthesis and anti-microbial activities of 1,3,5-trisubstituted-pyrazole derivatives containing a pyridyl moiety

Abstract

Claisen condensation of ethyl isonicotinate with different acetophenones gave the corresponding pyridyl-β-diketones, while the treatment with hydrazine hydrate yielded 3,5-disubstituted-1H-pyrazoles, which then converted 1,3,5-trisubstituted-pyrazole derivatives containing a pyridyl moiety by N-acylation with acyl chloride. The structures of all newly synthesized compounds are established by FTIR, 1H NMR, mass spectroscopy and elemental analysis, and in the case of compound 2e, analyzed by single-crystal X-ray diffraction further. The anti-microbial activities of the title compounds have been tested by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. The results showed that compounds 3c and 4c exhibited good inhibitory activity against all the tested organisms.