Synthesis and Anti-Inflammatory Activity of Some O-Propargylated-N-acetylpyrazole Derived from 1,3-Diarylpropenones

In search of novel effective potent therapeutic agents delivered by oral route for inflammation treatment, some novel O-propargylated-N-acetylpyrazole analogs (5a–j) were prepared by treating N-acetylpyrazole (4a–j) derived from 1,3-diarylpropenones (3a–j) with propargyl bromide. Claisen-Schmidt condensation of a series of substituted aryl ketones 1 and benzaldehydes 2 in glacial acetic acid afforded 1,3-diarylpropenones which on further treatment with hydrazine hydrate in acetic acid under reflux conditions afforded 1-acetyl-3,5-diaryl-4,5-dihydro(1H)pyrazoles (4a–j). The products were characterized by using spectroscopic techniques such as IR and NMR. In addition, the in vivo anti-inflammatory activity of the synthesized compounds was determined using the carrageenan-induced paw oedema method in rats.