Synthesis, characterization and antibacterial evaluation of new pyridyl-thiazole hybrids of sulfonamides

Abstract

Background and Aims: Sulfonamide drugs are a very old and noted group of small molecules, and are still one of the most important antimicrobial compounds. In this study, starting from sulfonamide drugs, new original compounds containing frequent and functional rings such as thiazole and pyridine were synthesized and their antimicrobial effects were evaluated. Methods: Eighteen new compounds were synthesized by converting the 4-amino group of the sulfonamides to thiourea, and continued by thiazole ring closure. Characterization of the compounds was carried out by FT-IR, H-1-NMR and C-13-NMR and HRMS. MIC values were obtained in antimicrobial activity studies, which were carried out by Broth Microdilution method. Results: Compounds 3p-r had an effect of 32 mu g/ml against B. spizizenii. In addition, compounds 3d-f and 3p-r each showed effect against different gram-positive bacteria. Compound 3r had an MIC of 128 mu g/mL against gram-negative organisms. The rest of the series did not affect gram-negative bacteria. In the study, chloramphenicol and sulfamethoxazole were used as standards. Conclusion: Sulfanilamide and sulfadiazine derivatives showed higher inhibitory effects compared to the rest of the series. 3d-f and 3p-r showed inhibitor activity against gram-positive bacteria, conversely to the standard drug sulfamethoxazole, which possibly means that the mechanism of action is not same.