Synthesis of biologically as well as industrially important 1,4,5-trisubstituted-1,2,3-triazoles using a highly efficient, green and recyclable DBU-H2O catalytic system

Substituted 1,2,3-triazoles are important heterocyclic molecules with applications in diverse research areas. 1,3-Dipolar cycloaddition reaction of azides and enolizable compounds is an important method of generating substituted 1,2,3-triazoles. However, the reported methods in the literature for 1,3-cycloaddition of aryl azides involve long reaction time, use of hazardous/volatile reagents, and toxic organic solvents. In this paper we have reported the novel environment friendly protocols for the synthesis of 1,4,5-trisubstituted-1,2,3-triazoles by reaction of various aryl azides with active methylene compounds in a DBU-water system under conventional heating, ultrasonic and microwave irradiation. The methodologies defined herein showed synthetic advantages in terms of high atom economy, low environmental impact, mild reaction conditions and good yields in shorter reaction time and recyclability of the reaction medium.