Synthesis of biologically active biheterocyclc oxadiazolyl benzofurans and other derivatives of benzofuran

Abstract

Various 5?-substituted-3-methoxy-[(1,3?,4-oxadiazol-2?- yl)]-benzofurans have been synthesized by different routes by using 3-methoxybenzofuran-2-carboxyhydrazide 2 as an intermediate. The carboxyhdrazide 2 on refluxing with various isothiocyanates produced carbothiosemicarbazides (3a-f), which have been subjected to oxidative cyclization to obtain oxadiazoles (4a-f). In an another route compound 2 has been refluxed with different carboxylic acids in presence of POCI3 to obtain corresponding oxadiazoles (7a-c). Reaction of 2 with appropriate aldehydes and ketones leads to the formation of corresponding hydrazones (11a-m). All the synthesized compounds have been characterized by spectral data and screened for antibacterial and some selected compounds for antiinflammatory activity.