PYRAZOLONE SCAFFOLDS IN MEDICINAL CHEMISTRY: SYNTHETIC STRATEGIES, STRUCTURAL FEATURES, AND PHARMACOLOGICAL SIGNIFICANCE

Pyrazolones represent an important class of nitrogen-containing heterocyclic compounds that have attracted significant attention due to their diverse chemical reactivity and wide range of biological activities. Structurally, pyrazolones exist in keto–enol tautomeric forms, which strongly influence their physicochemical properties and biological behaviour. The presence of multiple reactive centres within the pyrazolone core enables extensive functionalization, making them valuable scaffolds in synthetic and medicinal chemistry. This review provides a comprehensive overview of the synthesis, structural features, and functionalization strategies of pyrazolone derivatives, with particular emphasis on recent developments. In addition, the pharmacological significance of pyrazolones is discussed, highlighting their antibacterial, Antiinflammatory, antiviral, radioprotective, antioxidant, hepatoprotective, and SARs. Special attention is given to their emerging role in antiviral therapy, including potential applications against SARS-CoV-2 through interactions with viral targets such as the main protease and other replication-related enzymes. By summarizing current research trends and structure–activity relationships, this review aims to provide valuable insights for the rational design of novel pyrazolone-based therapeutics and to stimulate further research in drug discovery and development.