Synthetic Strategies and Emerging Therapeutic Interventions of Isoxazole and its Molecular Hybrids

Isoxazole is an important heterocyclic scaffold that has attracted considerable attention in medicinal chemistry because of its wide range of biological activities and favorable physicochemical characteristics. The isoxazole ring's usefulness as a favored scaffold in contemporary drug design and discovery has been highlighted by the production of many bioactive molecules and therapeutically relevant medications through its insertion into various molecular frameworks. This review discusses recent advances in the synthesis, reactivity, and therapeutic applications of isoxazole derivatives. It focuses on modern synthetic methods, such as microwave-assisted synthesis, 1,3- dipolar cycloaddition, visible-light photocatalysis, multicomponent reactions, and transition-metalcatalyzed approaches, which offer effective, regioselective, and sustainable ways to build isoxazole frameworks. In order to increase biological activity, improve selectivity, and broaden therapeutic potential, the isoxazole nucleus is carefully coupled with other pharmacophoric moieties in isoxazole- based hybrid compounds, which are becoming more and more popular. These hybrid compounds have shown a wide range of pharmacological actions, such as enzyme inhibitory, antioxidant, anticancer, antibacterial, and anti-inflammatory effects, underscoring their importance in the hunt for new therapeutic candidates. Structure-activity relationship (SAR) studies are also emphasized to better understand how structural changes affect biological activity. A 4-OEt substituent increased the antiproliferative activity of isoxazole-naphthalene hybrids, while electron-withdrawing substituents like Cl, F, and NO2 enhanced antibacterial activity in isoxazole-acridone hybrids, according to representative SAR investigations. Furthermore, efficacy and selectivity were strongly impacted by linker length, heteroatom inclusion, and molecular hybridization with heterocyclic scaffolds. In order to demonstrate the translational relevance and therapeutic value of this scaffold in modern drug development, the article also briefly examines a few clinically utilized medications that contain the isoxazole moiety. All things considered, this review provides a simple but thorough overview of recent advancements in isoxazole chemistry and hybrid molecule design. It also offers insightful information about the logical design and potential future development of novel therapeutic agents with enhanced and potential clinical relevance.