A simple and efficient synthesis of new fluorophore 4-hydroxy pyrazolo[1,5-a]pyridines through a tandem reaction

Abstract The cascade reaction of ethyl pyrazole-5-carboxylate with α, β-unsaturated ester leading to 4-hydroxy pyrazolo[1,5-a]pyridine derivatives has been developed. A possible mechanism is proposed. The resulting pyrazolo[1,5-a]pyridines present strong fluorescence in solutions.