Zinc oxide surface: a versatile nanoplatform for solvent-free synthesis of diverse isatin derivatives

Abstract

Multicomponent reactions performed on the surface of nanostructured zinc oxide gave 3,3-bis(indolyl)indolin-2-one and xanthene derivatives with excellent yields. Both Lewis acidic (Zn2+) and basic (O2−) sites on the surface of zinc oxide were utilized to perform the aforementioned transformations. The significance of surface catalysis was further proved by performing the experiment with surface masked zinc oxide. The developed zinc oxide nanocatalyst was reusable up to five times without significant loss in its activity.