Novel Acrylamide-Pyrazole Conjugates: Design, Synthesis and Antimicrobial Evaluation

A novel series of acrylamide-pyrazole conjugates were synthesized using a new strategy starting from 3-isobutyl-1-phenyl-1 H - pyrazole-4-carbaldehyde 1 . The reaction pathway was performed via unexpected routes to generate new pyrazole derivatives through the reaction of pyrazole methylene malononitrile 3a or pyrazole acrylic acid ethyl ester derivative 3b respectively with 2-Cyano- N- aryl acetamide derivatives 4a -e to yield the unexpected phenyl-1 H -pyrazol-4-yl)- N -aryl-acrylamide derivatives 7a -e . The structures of the synthesized compounds were confirmed via elemental and spectroscopic analysis (IR, 1 H NMR, 13 C NMR). The antibacterial and antifungal activities of the compounds were estimated against some species of Gram (-ve) bacteria such as Klebsiella pneumoniae and Gram (+ve) bacteria that are experiencing a high rate of antibiotic resistance nowadays and against Candida albicans fungus. Compound 7c showed activities against Escherichia coli (inhibition zone 23 +/- 1 mm, and Klebsiella pneumoniae (inhibition 21 +/- 1mm (as compared to Gentamicin (inhibition zone 27 +/- 0.1 mm) & (inhibition zone 29 +/- 0.5 mm), and exhibiting potent inhibitory activity toward candida albicans fungus (inhibition zone 25 +/- 1 mm) compared to Nystatin (inhibition zone 28 +/- 0.2). Most of the novel synthesized pyrazoles showed significant potencies as compared to standard antibiotics.