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(3H)-one were isolated in moderate to good yields with broad functional group tolerance.