A rapid and high efficient microwave promoted multicomponent domino reaction for the synthesis of spirooxindole derivatives

A simple, efficient and rapid method has been developed for synthesis of 6,6-dimethyl-4-phenyl-6,7-dihydro-1H-spiro[furo[3,4-b]quinoline-9,3′-indoline]1,2′,8(3H,4H,5H)-trione derivatives. These heterocycles were prepared through domino one-pot and multicomponent condensation reactions of isatins, dimedone, and anilinolactones in the presence of alum (15 mol%) as an inexpensive, nontoxic, convenient, and available Lewis acid catalyst under microwave irradiation. The corresponding products have been obtained in excellent isolated yields between 78% and 90%, with high purity, in short reaction times about 10–12 min and easy work up.