Convenient regioselective reaction in presence of H3PW12O40: synthesis and characterization of pyrazolo[3,4-b]quinoline-3,5-diones

摘要

We describe regioselective synthesis of pyrazolo[3,4-b]quinoline derivatives by multicomponent reaction of dimedone, 5-aminopyrazolone, and aromatic aldehydes in presence of H3PW12O40 as catalyst. When this multicomponent reaction was investigated without catalyst under reflux conditions, a mixture of products was obtained, while the reaction successfully proceeded to formation of pyrazolo[3,4-b]quinoline in presence of H3PW12O40. Good product yield, short experimental time, and low-cost catalyst provide convenient synthesis for formation of pyrazolo[3,4-b]quinoline pharmacological compounds.