Metal-free synthesis of 1,2,3-triazoles by azide–aldehyde cycloaddition under ultrasonic irradiation in TSIL [DBU-Bu]OH and in hydrated IL Bu4NOH under heating

Efficient and environmentally benign procedures have been reported for the synthesis of 1,4-disubstituted 1,2,3-triazoles by reaction of aryl azides with aldehydes in task-specific basic ionic liquid [DBU-Bu]OH under ultrasonic irradiation and in hydrated ionic liquid tetrabutylammonium hydroxide (Bu4NOH) under conventional heating. These protocols represent simple, general, and efficient approaches in terms of good yields, operational simplicity, easy workup, and shorter reaction time for the synthesis of 1,4-disubstituted 1,2,3-triazoles under metal-free conditions.