ChemInform Abstract: Microwave-Assisted Three-Component Reactions Leading to Pyrano-Fused Pyrazolo[3,4-b]pyridines

A series of pyrano-fused pyrazolo[3,4-b]pyridine derivatives with an aryl group presenting the 2-position of the pyridine nucleus have been synthesized by microwave-assisted three-component reactions of aldehydes, tetrahydropyran-4-one, and 3-methyl-1-phenyl-1H-pyrazol-5-amine in HOAc. This method is very efficient because of short reaction times and easy work-up, and it provides an efficient and promising synthetic strategy for the construction of the tricyclic pyrano-fused pyrazolo[3,4-b]pyridine skeleton.