Synthesis and antibacterial activity of some new heterocyclic compounds derived from p-bromobenzoic acid

         The scheme of this work involves synthesis of different five and six membered heterocyclic rings starting from 4-bromobenzoic hydrazide which was synthesized from their carboxylic acid.

          This work is divided into four different parts:

First part:

          This part involves the synthesis of fused tetrazole, triazole and triazine rings derived from the cyclization of (NH-NH₂) of the 5-(p-bromophenyl)-2-hydrazino-1,3,4-oxadiazole by treatment with sodium nitrite, formic acid, carbon disulfide and p-bromophenacyl bromide respectively. The oxadiazole derivative was synthesized by treating the previous acid hydrazide with carbon disulfide and potassium hydroxide then with hydrazine hydrate. Scheme I.

Second part:

          This part involves the synthesis of thiosemicarbazide, semicarbazide, triazole, thiadiazole, oxadiazole, oxazoline and thiazolidine derivatives from the reaction of (NH-NH₂) group of the starting material with different reagents. Scheme II.

Third part:

          This part involves the synthesis of pyrazole, phthalazine, pyridazine, oxapyridazine and triazole derivatives via the reaction of the acid hydrazide with different reagents. Scheme III.

Fourth part:

          This part deals with the study of antibacterial activities of some of the synthesized compounds and comparing these activities with that of the starting material. These activities were determined in vitro using disc diffusion method against three pathogenic strains of bacteria (Escherichia Coli, Klebsiella Pneumoniae and Proteus Vulgaris), the results revealed that some of these compounds showed measurable activity