Ionic Liquid Catalyzed Efficient Regioselective Synthesis of 1,4-Disubstituted 1,2,3-Triazoles Under Metal and Solvent Free Conditions

Abstract

Background: Catalyzed organic reactions avoiding the use of metal salts, metal complexes and organometallic compounds have tremendous applications especially within sensitive biological systems. The current work is an effort towards metal and solvent-free organo-catalyzed reactions. Objective: Unprecedented, one-pot regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles through azide-aldehyde (3+2) organo-click cycloaddition under metal and solvent-free conditions is described. Methods: The method presents a convenient approach towards the synthesis of functionally versatile 1,4-disubstituted 1,2,3-triazoles from easily accessible substrates using recyclable 1,8-diazabicyclo[ 5.4.0]undec-7-ene (DBU)-based ionic liquids as catalysts. Results: 1,4-disubstituted 1,2,3-triazoles were obtained in moderate to excellent yield using azidealdehyde (3+2) organo-click cycloaddition under metal and solvent-free conditions. Conclusion: The procedure reported herein for the synthesis of 1,4-disubstituted 1,2,3-triazoles is straightforward, greener, devoid of tedious workups and chromatographic separation.