NiO Nanoparticles: An Efficient Catalyst for the Multicomponent One‐Pot Synthesis of Novel Spiro and Condensed Indole Derivatives

Abstract

An efficient catalytic protocol for the synthesis of novel spiro[indoline‐3,4′‐pyrano[2,3‐c]thiazole]carbonitriles and condensed thiazolo[5′′,4′′:5′,6′]pyrano[4′,3′:3,4]furo[2,3‐b]indole derivatives is developed in a one‐pot three‐component approach involving substituted 1H‐indole‐2,3‐diones, activated methylene reagent, and 2‐thioxo‐4‐thiazolidinone under conventional heating and microwave irradiation. This paper describes the use of NiO nanoparticles as catalyst for the synthesis of novel spiro and condensed indole derivatives by Knoevenagel condensation followed by Michael addition. The advantageous features of this methodology are operational simplicity, high yield processing, and easy handling. The particle size of NiO nanoparticle was determined by XRD. After reaction course, NiO nanoparticles can be recycled and reused without any apparent loss of activity.