Fluorinated Heterocycles in Medicine: A Comprehensive Review with Focus on Quinolines, Pyrazoles, and Pyridines

Fluorinated heterocycles have become fundamental structures in contemporary pharmaceutical chemistry, constituting around 25% of all drugs available on the market. This in-depth review explores the medicinal uses of fluorinated heterocycles, focusing particularly on three important classes: fluorinated quinolines, pyrazoles, and pyridines. Fluorinated quinolines, such as fluoroquinolone antibiotics, have transformed antimicrobial treatment by simultaneously inhibiting DNA gyrase and topoisomerase IV. Fluorinated pyrazoles, like celecoxib and its associated anti-inflammatory drugs, exhibit selective inhibition of cyclooxygenase-2 with enhanced therapeutic profiles. Fluorinated pyridines include a wide range of therapeutic applications, from antiviral medications like favipiravir to central nervous system drugs featuring trifluoromethylpyridine groups. The deliberate addition of fluorine enhances metabolic stability, bioavailability, and selectivity for targets while altering physicochemical characteristics that are vital for drug efficacy. Structure-activity relationship analyses illustrate how the positioning of fluorine substitution affects biological activity, with distinct patterns identified for each class of heterocycles. Despite their achievements, challenges persist including the emergence of resistance to fluoroquinolones and safety issues linked to certain fluorinated structures. Ongoing research emphasizes new synthetic techniques, combination treatments, and applications in precision medicine. This review compiles existing knowledge on fluorinated heterocycles in medicine, offering insights into their mechanisms, clinical uses, and potential for future therapies.