L-Proline-Based Natural Deep Eutectic Solvents as Efficient Solvents and Catalysts for the Ultrasound-Assisted Synthesis of Aurones via Knoevenagel Condensation

Aurones are minor flavonoids that possess a wide variety of bioactivity, including antioxidant, anticancer, and enzyme inhibitory activity. L-proline-based natural deep eutectic solvents (NaDES) were synthesized applied as catalysts for the Knoevenagel condensation reaction between benzofuranone substituted benzaldehydes to produce aurones in high yields purity. The vanillin served model reaction. After screening three NaDESs, testing microwave, well ultrasound energy sources, we concluded optimum results obtained using L-proline/glycerol 1:2 catalyst solvent irradiation. scope was evaluated benzaldehydes, corresponding moderate satisfactory (57–89%) An important additional feature described methodology is recyclability reusability NaDES, which recycled effectively reused after 6 cycles.