Monoclinic zirconia nanoparticle-catalyzed regioselective synthesis of some novel substituted spirooxindoles through one-pot multicomponent reaction in a ball mill: A step toward green and sustainable chemistry

A highly efficient, green as well as atom economical protocol for the synthesis of substituted spirooxindoles from m-ZrO₂ NPs catalyzed multicomponent reaction of isatin derivatives with ethyl cyanoacetate and 1,3-dicarbonyl compounds in a ball mill has been established. Because of the simple and readily available starting materials, easy operation, and high bioactivity of substituted spirooxindoles, this strategy can be broadly applied to medicinal chemistry. The recyclability of the m-ZrO₂ Nps catalyst is another emphasis of proposed methodology.