One-pot, three-component synthesis of spirooxindoles catalyzed by ZnO nano-rods in solvent-free conditions.

Recyclable ZnO nano-rods catalyst as a most efficient and straightforward protocol for one-pot, three-component synthesis of spirooxindole derivatives at room temperature under solvent-free conditions in both reaction media and work-up procedure is described. This method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation (grinding), room temperature, low cost and green.