Selective and Scalable Electrosynthesis of 2H‐2‐(Aryl)‐benzo[d]‐1,2,3‐triazoles and Their N‐Oxides by Using Leaded Bronze Cathodes

Electrosynthesis of 2H‐2‐(aryl)benzo[d]‐1,2,3‐triazoles and their N‐oxides from 2‐nitroazobenzene derivatives is reported. The electrolysis is conducted in a very simple undivided cell under constant current conditions with a leaded bronze cathode and a glassy carbon anode. The product distribution between 2H‐2‐(aryl)benzo[d]‐1,2,3‐triazoles and their N‐oxides can be guided by simply controlling the current density and the amount of the charge applied. The reaction tolerates several sensitive functional groups in reductive electrochemistry. The usefulness and the applicability of the synthetic method is demonstrated by a formal synthesis of an antiviral compound. Electrosynthesis takes the lead: Electrosynthesis enables green and atom‐economic access to 2H‐2‐(aryl)‐benzo[d]‐1,2,3‐triazoles or their N‐oxides from 2‐nitroazobenzenes. This operationally very simple protocol is conducted in an undivided cell by constant current electrolysis. Optionally, inexpensive NaOH can be used as both a supporting electrolyte and additive.