Electrochemically Enabled Cascade Cyclization Reaction of Aromatic Aldehydes and Pyrazol-5-amines: Synthesis of Bis-pyrazolo[3,4‑<i>b</i>:4′,3′‑<i>e</i>]pyridines

A facile method for the synthesis of bis-pyrazolo­[3,4-b:4′,3′-e]­pyridines from easily available aromatic aldehydes and pyrazol-5-amines was developed via electrochemistry. The reaction proceeded smoothly under metal and external chemical oxidant-free conditions, giving a variety of bis-pyrazolo­[3,4-b:4′,3′-e]­pyridines in moderate yields.