Abstract

SYNTHESIS AND PHARMACOLOGICAL SCREENING OF SOME N`[SUBSTITUTED SULFONYL]-1,3-BENZOXAZOLE-5- CARBOHYDRAZIDES AS AN ANTI-INFLAMMATORY AGENTS

Dr. Sunila T. Patil¹*, Dr. Parloop A. Bhatt²

ABSTRACT

The main objective of the medicinal chemistry is to synthesize the compounds that show promising activity as therapeutic agents with lower toxicity. Benzoxazole derivatives are very useful compound with well known biological activity. Notable among these are antibacterial, antiviral, antifungal, analgesic, anti-inflammatory and antitubercular. In the current research work, the title compounds N`[substituted sulfonyl]-1,3-benzoxazole-5-carbohydrazide, were synthesized by electrophilic aromatic substitution on p-hydroxy methyl benzoate (I) with concentrated nitric acid and concentrated sulfuric acid under reflux condition. Compound (II) on reduction with sodium dithionate with alcohol gives 3-amino-4-hydroxy-benzoic acid methyl ester (III). Reaction of compound (III) with two appropriate aliphatic acids (formic acid and acetic acid) produced corresponding 2-subtituted benzoxazole-5-carboxylic acid methyl esters. The reaction of compounds (IV) with hydrazine hydrate in ethanol on refluxing yielded the corresponding 2-substituted benzoxazole-5-carboxylic acid hydrazides. On further reaction of compounds (V) with the different sulfonyl chloride derivatives afforded the corresponding eight N`[substituted sulfonyl]-1,3-benzoxazole-5-carbohydrazide. The identification and characterization of the synthesized compounds were carried out by Elemental analysis, melting point, Thin Layer Chromatography, FT-IR, NMR and Mass data to ascertain that all synthesized compounds were of different chemical nature than the respective parent compound. The compounds were screened for anti-inflammatory activity. The anti-inflammatory activity of compounds were done by using formalin induced rat paw edema method. The test compounds VIa, VId and VIe showed significant anti-inflammatory activity compared with the standard drug Ibuprofen.

Keywords: Anti-inflammatory activity, Benzoxazole, Formalin, Ibuprofen.