Synthesis and pharmacological screening of N-substituted anthranilic acid derivatives

In the present work eight newly synthesized structurally diverse anthranilic acid derivatives were evaluated for their anti-inflammatory activity against carrageenan induced oedema in albino rats. All the anthranilic acid derivatives were compared for their percentage inhibition of the oedema using control drug phenylbutazone. The desired anthranilic acid derivatives 5-bromo-2-{[5-{[(2E)-3-(2-substitutedphenyl)prop-2-enoyl]amino}-1,3,4,-oxadiazol-2- yl) methyl]amino}benzoic acid (compounds 1-4) weresynthesized by condensation of 5-bromo-N - (2′-amino acetyl -1′,3′,4′-oxadiazol-5′-ylmethyl) anthranilic acid and substituted aromatic aldehydes, respectively, and the compounds 5-bromo-N - [2′-amino [1-"acetyl-5"-(substitutedaryl-2'-pyrazolin-3-yl]-1′3′4′-oxadiazol-5′- ylmethyl) anthranilic acid (compounds 5-8) were synthesized by the condensation of compounds (1-4) with the hydrazine hydrate in the presence of few drops of glacial acetic acid. Compound 5 was found to be a potent member of this series which showed 51.05% anti-inflammatory activity with ED50 of 51.05 mg/kg while phenylbutazone exhibited 47.23% anti-inflammatory activity at the same dose. The structures of the newly synthesized compounds have been established on the basis of spectral (FTIR and ¹H-NMR) data and elemental analysis.