Microwave-assisted efficient and highly chemoselective synthesis of oxazolo[5,4-B]quinoline-fused spirooxindoles via catalyst- and solvent-free three-component tandem Knoevenagel/Michael addition reaction

[Display omitted] A microwave-assisted, chemoselective synthesis of oxazolo[5,4-b]quinoline-fused spirooxindoles have been achieved via three-component tandem Knoevenagel/Michael addition reaction of 5-amino-3-methylisoxazole, β-diketones and isatin in good to excellent yields under catalyst- and solvent-free conditions. The main advantages of this protocol are easiness of work-up, mild reaction and eco-friendly reaction conditions.