4-oxadiazole-thione

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.

5-(7-bromo-5-chloro-3-methylbenzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 1 underwent a series of hetero-cyclization reactions with different chemical reagents such as triethylorthoformate, acetic acid in phosphorous oxychloride, benzoic acid in phosphorous oxychloride,  N,N’carbonyldiimidazole in dioxane, carbon disulphide in pyridine to afford substituted 1,3,4-oxadiazoles 2, 3, 4, 5 and 6 respectively.  Extending the reaction of 6 with 4-(2-chloroethyl) morpholine hydrochloride afforded 7. The structures of the newly synthesized compounds were established on the basis of spectral analysis such as IR, 1H NMR, 13C NMR and Mass spectral data. The synthesized compounds were screened for their antimicrobial activity against two gram positive and gram negative bacteria and a fungus and found to possess good activity against selected strains.