Synthesis, Characterization and Biological Evaluation of Novel Halogenated 1,3,4-Oxadiazoles Derieved from Substituted Pyrazole-3-Carbohydrazide

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.