Biosynthesized Silver Nanoparticles Catalyzed Aqueous-Phase Synthesis of Isoxazol-5(4H)-One Derivatives

We developed a sustainable and efficient protocol for synthesizing isoxazol-5(4H)-one derivatives using green synthesized silver nanoparticles as a green nonocatalyst. The one-pot, three-component reaction of aromatic aldehydes, ethyl acetoacetate, and hydroxylamine hydrochloride proceeded smoothly in aqueous phase at room temperature, affording the target compounds in high to excellent yields with short reaction times. The plant-derived silver nanoparticles demonstrated exceptional catalytic activity while offering advantages such as low toxicity, cost-effectiveness, and easy handling. Notably, electron-donating substituents on the aromatic aldehydes enhanced reactivity, whereas steric and electronic factors influenced reaction efficiency. This method aligns with green chemistry principles by eliminating organic solvents, minimizing energy consumption, and utilizing a biodegradable catalyst. The protocol provides a practical, eco-friendly, and scalable approach to heterocyclic synthesis, making it a valuable addition to sustainable organic transformations.