Preparation of 2‐Aryl‐2H‐benzotriazoles by Zinc‐Mediated Reductive Cyclization of o‐Nitrophenylazophenols in Aqueous Media without the Use of Organic Solvents

Abstract Zinc powder‐mediated reductive cyclization of o ‐nitrophenylazophenols in alkaline solution affords the corresponding 2‐aryl‐2 H ‐benzotriazoles in high yields under mild reaction conditions. No organic solvents are used in the reaction and only minimal amounts in the work‐up.