Abstract
Ethyl 2-(1H-pyrazol-1-yl)acetate (1) was synthesized by the reaction of ethyl chloro acetate with 1H-pyrazole. Compound (1) was refluxed with hydrazine hydrate to get 2-(1H-pyrazol-1-yl) acetohydrazide (2). N'-arylidine-2-(1H-pyrazol-1-yl)acetohydrazide derivatives/Schiff's base (3a-3e) were synthesized by condensation reaction of compound (2) with appropriate aryl aldehydes. Schiff's base (3a-3e) was cyclized by reflux with acetic anhydride to obtained 1-(5-((1H-pyrazol-1-yl)methyl)-2-aryl-1,3,4-oxadiazol-3(2H)-yl)ethanone derivatives (4a-4e). The structures of the synthesized compounds were characterized by Infrared, H-1-NMR, C-13-NMR, and mass spectra analysis data. Synthesized compounds (4a-4e) were evaluated against some common pathogenic Gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The result of antibacterial activity was compared with standard drug ampicillin. These compounds were more effective against Gram-negative bacteria than Gram-positive bacteria and compound 4c was found most active compound than other remaining compounds.