Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazoles Through a One-Pot Three Component Reaction of Boronic Acids, Sodium Azide and Active Methylene Compounds Under Ball-Milling Conditions

In this study, we report a mild and efficient one-pot synthesis of 1,4,5-trisubstituted 1,2,3-triazoles via a three-component reaction of aryl boronic acids with sodium azide and active methylene compounds under ball-milling condition. In order to determine optimized reaction conditions, several grinding auxiliaries (basic, neutral and acidic alumina, silica gel, K10 and KSF), bases (DBU, DABCO, piperidine, triethylamine, potassium t-butoxide and potassium carbonate) and copper salts under ball-milling conditions were examined. Using the optimized condition procedure, a wide variety of 1,4,5-trisubstituted 1,2,3-triazole derivatives were prepared in very good yields. All products were well-characterized by ¹H-NMR and ¹³C-NMR spectroscopy. This environmentally friendly protocol offers several advantages including high yields of products, relatively short reaction time and simple work-up procedure.