Objective: The objective of the paper was to synthesis and characterization of new isoxazole bearing pyrazole derivatives and evaluate them for antibacterial activity. Material and methods: The isoxazole bearing pyrazole derivatives have been synthesized by the utilize the four-step process. Total Ten compounds have been synthesized and characterized by IR, 1HNMR, elemental and mass spectral analysis. The final compounds (PIA-1 to PIA-10) have been evaluated for antibacterial activity by disk

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... ffusion method using sulfamethoxazole as standard drug. Result and Discussion: The IR spectra of compound PIA-1 to PIA-10 shown the characteristics peak at 3052 (N-H), 2964 (C-H), 1628 (C=O), 1448 (C=N), 1625 (C=C), 1126 (C-O); 1015 (C-Br); 850 (C-Cl) and 1102 (C-F). The 1HNMR spectrum show the characteristics peak δ 6.68-6.70 (d, 2H, Ar-Fluorine), 7.14-7.16 (d, 1H, Ar-chlorine), 7.28-7.30 (m, 5H, Ar-H), 7.58-8.00 (d, 2H, Ar-Chlorine), 7.75-7.78 (d, 2H, Ar-Fluorine), 8.25 (s, 1H, Ar-H isoxazole), 10.97 (s, 1H, -Ar-H pyrazole); 7.26 (s, 1H, Ar-Cl). The antibacterial evaluation of the synthesized compounds stated that Isoxazole-pyrazole derivatives exhibit considerable inhibitory effect on all bacteria strains at both 50 µg/ml and 100 µg/ml dosing levels. PIA-1, PIA-2, PIA-3, PIA-4 had the highest activity in gram positive bacterial stains and PIA-1, PIA-3, PIA-4 and PIA-10 have shown best activity against gram negative bacteria. Conclusion: The antibacterial activity of the synthesized compounds (PIA-1, PIA-3, PIA-4 and PIA-5) was significantly similar or better than that of standard Drug used for comparison. These Isoxazole bearing pyrazole compounds have demonstrated potency as a superior antibacterial agent, although more in-vivo research on the efficacy and dosage regimen of the compounds is needed. Keywords: Antibacterial activity, Pyrazole, [...]