Synthesis of some new 1, 2, 3-selena and thiadiazole derivatives

Several compounds of 1,2,3-selena and/or thioadizoles with evident biological activity were previously reported by the authors, certainly as antibacterial and antifungal agents [1-6] e.g. 1,2,3-thiadiozolo and/or selenadiazolo-4-yl-pheynyl-hydrazophyrazolones [10] were tested in vitro against a variety of Gram positive strains of bacteria. Certain compounds show strong activity against Bacillus sub., staphylococcus areus and Mycobacterium phlei. Thus, pyridine [7], furan [8] and thiophene [9] containing 1,2,3-selena and thiadiazoles motivated their synthesis and testing as biologically active compounds. In this work, compounds [1-3] were easily condensed with semicarbazide to give the corresponding semicarbazones [4-6] respectively. On the other hand, the purified semicarbazones [4-6] were then oxidized either with selenium dioxide [11] in glacial acetic acid to give 1,2,-3-selenadiazole Derivatives[9,11] or with thionyl chloride[12] to afford, 1,2,3-thiadiazole derivatives[10,12]