Synthesis and Anti‐inflammatory Activity of Some Novel Pyrazole Derivatives of Gallic Acid

In the present study, a new series of [5‐substituted‐3‐(phenylamino)‐1 H ‐pyrazol‐1yl] (3,4,5‐trihydroxyphenyl)‐methanone (4a‐j) have been synthesized. 3, 4, 5‐Trihydroxy benzohydrazide (1) was synthesized from propyl gallate and hydrazine hydrate in presence of ethanol. Chalcones (2a‐j) were synthesized from acetanilide and various aromatic aldehydes in presence of ethanol and sodium hydroxide solution. By refluxing the compound (1) and compounds (2a‐j) in presence of ethanol yielded [5‐substituted‐3‐(phenylamino)‐4.5‐dihydropyrazol‐1yl] (3,4,5‐trihydroxy phenyl)‐methanone (3a‐j). The final compounds [5‐substituted‐3‐(phenylamino)‐1 H ‐pyrazol‐1yl] (3,4,5‐trihydroxyphenyl)‐methanone (4a‐j) were synthesized by treating compounds (3a‐j) with bromine water. The synthesized compounds have been characterized by IR, 1 HNMR and Mass spectral data. The compounds were evaluated for in vivo anti‐inflammatory activity by carrageenan induced paw edema test. In general all compounds were found to exhibit good anti‐inflammatory activity.