Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid.

Switchable multicomponent reactions involving 3-substituted-5-amino-1,2,4-triazoles, pyruvic acid, and salicylaldehydes were studied under different conditions. Upon conventional heating, benzotriazolooxadiazocine-5-carboxylic acids were formed in the three-component reactions as single reaction products. Upon ultrasonic activation or mechanical stirring at room temperature, the multicomponent reaction of the same starting materials led to the formation of only tetrahydrotriazolopyrimidine derivatives.