thiosemicarbazide

5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazides 1a-b  on reaction with phenylisothiocyanate, potassium thiocyanate, carbon disulphide in pyridine and carbon disulphide in KOH followed by hydrazine hydrate afforded nitrogenous, sulphur bridgehead heterocycles 2-5a-d respectively. The structures of the newly synthesized compounds were elucidated by elemental analysis and spectral data such as IR, 1H NMR, 13C NMR and mass spectra. In addition the in vitro antibacterial and antifungal properties were tested for these synthesized compounds against B. subtilis, S. aureus, E. coli, P. aeruginosa and A. niger compared with ampicillin and clotrimazole as reference drugs. Synthesized compounds were found to possess moderate to excellent activity against selected strains.

In the present study, a series of S-[5-(phenylamino)-1,3,4-thiadiazole-2-yl] benzenecarbothioate and S-[5-(phenyl amino)- 1,3,4-thiadiazole-2-yl] ethanethioate were prepared by refluxing benzoyl chloride and acetyl chloride in presence of potassium carbonate with 5-(phenyl amino)-1,3,4-thiadiazole-2-thiol. 5-(Phenyl amino)-1, 3, 4-thiadiazole-2-thiol were prepared by cyclization of arylthiosemicarbazide with carbondisulphide. The structure of new compounds prepared during present investigation have been authentically established by their IR, 1H NMR and Mass spectral studies. The antibacterial and antifungal activities of thiadiazole derivatives also reported. Some of these derivatives exhibit significant antimicrobial activity. Key words: thiadiazole, thiosemicarbazide, antibacterial, antifungal.