An efficient one‐pot synthesis of Spiro[indoline‐3,11′‐pyrazolo[3,4‐f]pyrimido[4,5‐b]quinoline] derivatives

An efficient procedure for the synthesis of novel spiro[indoline‐3,11′‐pyrazolo[3,4‐f]pyrimido[4,5‐b]quinoline] derivatives has been developed by one‐pot condensation of 1H‐indazol‐6‐amine, isatin and barbituric acid or 2‐thiobarbituric acid, in the presence of L‐proline in refluxing EtOH. This method has the advantages of operational simplicity, high yield of products via a simple experimental and work‐up procedure. IR, 1H NMR, 13C NMR, 19F NMR and HRMS were used to identify the structures of all the synthesized compounds. An efficient procedure for the synthesis of novel spiro[indoline‐3,11′‐pyrazolo[3,4‐f]pyrimido[4,5‐b]quinoline] derivatives.