Synthesis of [1,2,3]Triazolo[1,5-a]quinoxalin-4(5H)-ones through Copper-Catalyzed Tandem Reactions of N-(2-Haloaryl)propiolamides with Sodium Azide

A simple and efficient approach for the synthesis of [1,2,3]triazolo[1,5-a]quinoxalin-4(5H)-ones is described. The methodology is based on a tandem reaction of 1-(2-haloaryl)propiolamides with sodium azide through a [3 + 2] azide–alkyne cycloaddition and intramolecular Ullmann-type C–N coupling process.