Mechanochemical Synthesis of 1,2,4‐Triazoles via a [3+2] Cycloaddition of Azinium‐N‐Imines and Nitriles

Abstract We report here a mechanochemical Cu‐catalyzed [3+2] cycloaddition of azinium‐ N ‐imines with nitriles under solventless grinding conditions. Various 1,2,4‐triazolos derivatives were obtained in 51–80% yields. The developed protocol offers advantages in functional‐group compatibility, scalability, no use of solvents, shorter reaction time, and without external heating. In addition, heterocyclic N ‐imines such as quinolinium and isoquinolinium salts are also suitable substrates, resulting in the production of 1,2,4‐triazolo[1,5‐ a ]quinoline and 1,2,4‐triazolo[5,1‐ a ]isoquinoline derivatives under mechanochemical conditions. magnified image