Multicomponent Strategy to Pyrazolo[3,4- b ]pyrrolo[3,4- d ]pyridine Derivatives under Microwave Irradiation.

A novel three-component reaction has been established that allows a flexible and practical approach to pyrazolo[3,4- b ]pyrrolo[3,4- d ]pyridine derivatives from phenylglyoxal, β-ketoamide, and 5-aminopyrazole with acetic acid as the solvent. Various dihydropyrazolo[3,4- b ]pyrrolo[3,4- d ]pyridin-6(3 H )-one were isolated in moderate to good yields with broad functional group tolerance.