One-pot three-component synthesis of functionalized spirooxindoles in gluconic acid aqueous solution

A general, efficient, and green method for one-pot synthesis of functionalized spirooxindoles through three-component condensation reaction of isatins, cyclohexane-1,3-diones, and barbituric acids is described employing gluconic acid aqueous solution (GAAS) as a novel reaction medium and catalyst. The reaction medium could be recycled and reused several times without significant loss of its efficiency.