New 1,3,4-thiadiazoles based on thiophene-2-carboxylic acid: Synthesis, characterization, and antimicrobial activities

Novel 1,3,4-thiadiazole derivatives were prepared by cyclization reaction of thiophene-2-carboxylic acid with N-arylthiosemicarbazides and POCl3. 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, H-1 NMR, and C-13 NMR spectroscopies and elemental analysis. (C) 2019 Elsevier B.V. All rights reserved.