SYNTHESIS AND ANTIMICROBIAL EVALUATION OF 3-METHOXY-5-NITRO-2-(1,3,4-OXADIAZOLYL, 1,3,4-THIADIAZOLYL AND 1,2,4-TRIAZOLYL) BENZOFURANS

Abstract

Methyl 5-nitrosalicylate upon refluxing with diethyl bromomalonate in dry acetone in presence of K2CO3 furnished 2-carbethoxy 5-nitro-3-benzofuranol (1). It was methylated successfully with dimethyl sulphate in dry acetone to give 3-methoxy-5-nitro-2-carbethoxybenzofuran (2). Compound 2 on reaction with hydrazine hydrate gave carbohydrazide (3) which was further condensed with different isothiocyanates to yield thiosemicarbazides (4a-e). These thiosemicarbazides were cyclized into oxadiazolyl, thiadiazolyl and triazolyl benzofurans (5a-e), (6a-e) and (7a-e), respectively. These newly synthesized compounds were characterized by elemental analysis and spectroscopic methods and they were screened for antimicrobial activity. Some of the compounds were also screened for their antimicrobial activity.