Synthesis and Antimicrobial Efficacy of Novel 1,3,4-Thiadiazole Derivatives Against Key Bacterial and Fungal Strains

Two series of new 1,3,4-thiadiazole derivatives were synthesized through heterocyclization of methyl 2-(3,5-dibromo-2-hydroxybenzylidene)hydrazine-1-carbodithioate (4) and methyl (E)-2-(1-(5,7-dibromobenzofuran-2-yl)ethylidene)hydrazine-1-carbodithioate (5) with various hydrazonoyl chlorides, respectively. The structures of the newly synthesized products were elucidated through elemental analysis and spectral data. Eight new compounds from the first series (i.e. containing dibromohydroxybenzene moiety) were evaluated for their antimicrobial activity against Staphylococcus aureus ATCC 6538-P as the Gram-positive bacteria, Escherichia coli ATCC 25933 as the Gram-negative bacteria, Candida albicans ATCC 10231 as a yeast, and the filamentous fungus Aspergillus niger NRRL-A326 in comparison with neomycin as a reference drug in the case of S. aureus, E. coli and C. albicans whereas cyclohexamide was used as a reference for filamentous fungi. The results showed that some of the novel compounds have promising antimicrobial activity.