Novel Coumarin Linked Pyrazoles, Thiazoles, and Thiadiazoles: Synthetic Strategies and in Vitro Antimicrobial Investigation

Aim: Emerging resistance among pathogens necessitates the development of novel antimicrobial agents. As a result, we aimed to synthesize new coumarins and study their antimicrobial activity with the hope of obtaining effective drugs.

Method: A series of coumarins were synthesized, characterized, and assessed for antimicrobial activity using broth microdilution and agar diffusion methods against Gram-positive (), Gram-negative () bacteria, and fungi ().

Results: Pyrazoles and revealed promising activities against all bacterial strains with MIC values ranging from 1.95 to 15.6 µg/ml. Notably, pyrazole with CF in 3-position of pyrazole ring demonstrated higher ability to inhibit strain with MIC value equal to penicillin G (3.91 µg/ml). It also exhibited the best bactericidal potency against with MBC value of 15.6 µg/ml while, pyrazole recorded the same MBC value against . Pyrazole demonstrated the strongest antifungal activity against both fungal strains with MIC and MFC values of 15.6, 7.81, 62.5, and 31.3 µg/ml against and , respectively.

Conclusion: These findings underscore the potential of coumarins, particularly compounds and , as effective antimicrobial agents and provide critical insights into the design of bioactive molecules.