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

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 POCl3 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.