Synthesis of Novel 1,4-Substituted 1,2,3-Triazoles by Water-Soluble (Salicyladimine) 2Cu Complex Catalyzed Azide-Alkyne Cycloaddition in Water

Background: 1,2,3-Triazoles represent an important structural motif frequently found in organic chemistry, biological science, medicinal chemistry, and material science. Thus, the synthesis of novel 1,2,3-triazoles derivatives by an efficient method has attracted considerable attention. Methods: In this paper, we developed a simple and efficient azidation system of biphenyl tosylhydrazones with sodium azide. A series of new 4-(1-azidoethyl)-1,1'-biphenyl derivatives were prepared by the metalfree reductive reaction and further reacted with aryl acetylenes to afford novel 1,4-substituted 1,2,3-triazoles by water-soluble (salicyladimine)2Cu complex catalyzed azide-alkyne cycloaddition in water. Results: The desired 1,4-substituted 1,2,3-triazoles were obtained in 27-94% yields in pure water without any organic solvent or phase transfer agents. Conclusion: The catalytic system presented here enables the use of easily accessible starting materials and good functional group tolerance.