Synthesis of Some Novel Bis[1,2,4]triazolo[3,4-b][1,3,4] thiadiazine Derivatives for Antimicrobial Evaluation

A new series of novel bis[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines 7a–j has been synthesized by the reaction of [5,5’- methylenebis(3-methylbenzofuran-7,5-diyl)]bis[(4-amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methanone] (6) with a variety of phenacyl bromides in ethanol under reflux for 6 h. All the newly synthesized compounds were tested for in vitro activity against certain strains of bacteria such as Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae and Shigella flexneri. Compounds 7a, 7c and 7g were highly active against the entire organism employed. Compound 7c showed the activity higher than the standard drug neomycin, and almost equal to the streptomycin. Compounds 7a–j were also screened for their antifungal activity against Aspergillus niger, Candida albicans, Aspergillus flavus and Rhizopus oryzae. Compounds with methoxyphenyl moiety 7d and dichlorophenyl moiety 7f showed significant activity against the tested fungal strains.