الفهرس 
Pyrazole
Materials and MethodsOnly 14 pages are availabe for public view
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Abstract
Derivatives of formyl pyrazole were synthesized by the reaction of acetophenone, 4-methyl acetophenone, 3-acetyl furan and/or 3-acetyl thiophen with phenl hydrazine derivatives. The product was treated with Vilsmeier reagent producing different formyl pyrazole derivatives (2a-f) which were characterized by FT-IR, 1H-NMR, Elemental analysis and Mass spectroscopy. The formyl pyrazole derivatives were reacted with chitosan to produce chitosan/ pyrazole Schiff base (3a-f). These Schiff base were characterized by FT-IR, Elemental analysis and TGA.
The antimicrobial activity of chitosan/ pyrazol Schiff base (CSB) was evaluated against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacterium (Escherichia coli) and fungus (Aspergillus niger). Results indicated a good inhibitory activity for (3b) when tested against B.cereus that gave inhibition zone of 7.5 ± 0.6 (mm), however (3f) gave a pronounced inhibitory activity against S. aureus and recorded 25 ± 2.0 (mm). All synthesized derivatives have no inhibitory activity against Gram-negative bacteria (E. coli). (3b) and (3c) exhibited inhibitory activity against tested A. niger that was used as a fungal model which gave 19 ± 0.9 and 18 ± 1.0 inhibition zone (mm) respectively. Thus, these results showed that, functionalization of chitosan with the hetero-cyclic compounds created biological activities of the synthesized derivatives; hence the synthesized pyrazole derivatives have not recorded any inhibitory activity before its immobilization onto chitosan.