ZnS Nanoparticles: An Efficient Catalyst for the One-Pot Synthesis of Spiro [Pyrrolidine-2, 3′-Oxindole] Derivatives from Phenothiazinyl Chalcones

ZnS-nanoparticles, as recyclable heterogeneous catalyst, efficiently promoted in the synthesis of spiro[pyrrolidine-2,3'-oxindole] derivatives through three-component reaction of isatin, alpha-amino acid and phenothiazinyl chalcones. An azomethine ylide generated by decarboxylative condensation of isatin with alpha-amino acid, and chalcones have been used as trapping dipolarophiles. ZnS nanoparticles were synthesized by aqueous chemical method. The advantages of this method lie in its simplicity, cost effectiveness, and easier scaling up for large scale synthesis.