A Facile Synthesis of Furo[3,4-e]pyrazolo[3,4-b]pyridine-5(7H)-one Derivatives via Three-Component Reaction in Ionic Liquid without Any Catalyst

A series of furo[3,4-e]pyrazolo[3,4-b]pyridine-5(7H)-one and indeno[2,1-e]pyridinzolo[3,4-b]pyridine5(7H)-one derivatives were synthesized via the three-conponent reaction of an aldehyde, 5-aminopyrazole and either tetronic acid or 1,3-indanedione in ionic liquid without any catalyst. The structures of the products have been established by spectroscopic data and further confirmed by X-ray diffraction, analysis. This method has the advantages of easier work-up, mild reaction conditions, high yields and an environmentally benign procedure.