New 1,3,4-Thiadiazoles Based on Thiophene-2 Acid: Synthesis, Characterization, and Antimicrobial Activities

Abstract

Novel 1,3,4-thiadiazole derivatives were prepared by cyclization reaction of thiophene-2-carboxylic acid with N-arylthiosemicarbazides and POCl<inf>3</inf>. The antibacterial activities of the synthesized compounds were tested against Gram-negative bacteria (Salmonella enteritidis, Salmonella typhimurium, Enterobacter aerogenes, Salmonella infantis, Salmonella kentucky, and Escherichia coli), Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Enterococcus durans), and the fungus Candida albicans using the disk diffusion method. Selected 1,3,4-thiadiazole derivatives exhibited effective antimicrobial activity against S. aureus, C. albicans, S. typhimurium, E. aerogenes, and S. kentucky. Therefore, 1,3,4-thiadiazole derivatives can be considered as bioactive agents for pharmacological and medicinal applications. The synthesized compounds were characterized by using IR, 1H NMR, and 13C NMR spectroscopies and elemental analysis. © 2019 Elsevier B.V.