One-pot synthesis and characterization of spirooxindole-3,4'-pyran derivatives via FeCl3-Catalyzed multicomponent reaction: A facile approach with high yields and eco-friendly methodology

A facile novel spirooxindole-3,4’-pyrans derivatives using FeCl₃ as a catalyst by one-pot three-component reaction. This is a typical cascade reaction with a maximum yield of ∼98 %. The synthesis of 28 derivatives followed using the multi-component reaction (MCR – single-step reaction). This phase goes through the fast knoevenagal condensation, Michael addition reaction, and catalyst recovery. We have developed the wider scope and limitations of the reaction using various isatin derivatives and active methylene compounds. The yield was further confirmed using FT-IR, ¹³C NMR, ¹H NMR, single crystal XRD, and Mass. These derivatives have good yields.