Nano-SiO2: a heterogeneous and reusable catalyst for the one-pot synthesis of symmetrical and unsymmetrical 3,3-di(aryl)indolin-2-ones under solvent-free conditions

Symmetrical and unsymmetrical 3,3-di(aryl)indolin-2-ones have been synthesized by nano-SiO2 as green, heterogeneous, and reusable catalyst under solvent-free conditions at room temperature via magnetic stirring and grinding methods. A plausible mechanism of condensation has also been presented.