One‐pot Two‐step Reaction for Synthesis of Poly‐substituted Pyrano[3,2‐c]pyridones and Spiro[indoline‐3,4′‐pyrano[3,2‐c]pyridine]‐2,5′(6′H)‐diones in Water

An efficient four‐component approach for the synthesis poly‐substituted pyrano[3,2‐c]pyridones and spiro[indoline‐3,4′‐pyrano[3,2‐c]pyridine]‐2,5′(6′H)‐diones in water has been established. During the reaction, the products were readily achieved through one‐pot two‐step reaction using solid acid as catalyst. The advantages of atom and step economy, the recyclability of heterogeneous solid acid catalyst, easy workup procedure, and the wide scope of substrates make the reaction a powerful tool for assembling pyrano[3,2‐c]pyridone skeletons of chemical and medical interest.