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)-1H-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)-1H-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, (HNMR)-H-1 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.