Synthesis and Biological studies of New 1,2-diazin-3,6-dione, 2,3- phthalazin-1,4-dione,1,2,4-Triazole, 6H-1,3,4-Thiadiazine,and N-substituted -∆4- Oxazoline Derivatives

The scheme of this work involves synthesis of different five and six membered heterocyclic rings starting from 4-nitrophenyl hydrazine and two different acid hydrazides (benzoic hydrazide and            p-chlorobenzoic hydrazide) which were synthesized from their carboxylic acids.This work is divided into four different parts:

First part:

          This part involved the synthesis of fused thiadiazine ring derived from the cyclization of (-NH₂ and –SH) of the 3-mercapto-4-amino-5-(aryl)-1,2,4-triazole by treatment with p-bromophenacyl bromide. The triazole derivatives were synthesized by treating the previous acid hydrazides with carbon disulfide and potassium hydroxide Scheme I.

Second part:

          This part involved the synthesis of phthalazin and pyridazin-3,6-dione derivatives from the reaction of (-NH-NH₂) group of the starting materials with succinic , maleic and phthalic anhydrides. Scheme II

Third part:

          This part involved the synthesis of different N-substituted-∆⁴-oxazoline derivatives via the reaction of the acid hydrazides with phenyl and 1-naphthyl isocyanates and cyclization of the resulted products with  p-bromophenacyl bromide. Scheme II.

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 materials. 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.