Synthesis of 2‐Substituted 1,2,3‐Triazoles via an Intramolecular N – N Bond Formation

An efficient synthesis of 2‐aryl 1,2,3‐triazoles based on an intramolecular N – N bond formation is described. Selective activation of bis‐hydrazone at the dimethylamino hydrazone group with MeI forms a mono‐hydrazonium species. Treatment of the hydrazonium species with a base smoothly leads to the formation of a wide variety of 2‐aryl‐1,2,3‐triazoles in good to excellent yields. The reaction likely follows an intramolecular S N 2 displacement mechanism with the trimethylammonium moiety serving as a good leaving group for the intramolecular N – N bond formation.