Tandem Ring‐Opening/Double Ring‐Closing Synthesis of 1,2,4‐Triazolo[1,5‐a]pyridines from Chromone‐Containing Acrylonitriles

Abstract We studied a reaction of chromone‐containing acrylonitriles and cyanoacrylates with acid hydrazides. This reaction turned out to be a method for the synthesis of salicyloyl‐substituted 1,2,4‐triazolo[1,5‐ a ]pyridines. The synthesis developed is a tandem ring‐opening/double ring‐closing process. This synthetic approach is characterized by low toxic solvents (ethanol, butanol) and mediator (Et 3 N), 37–84% yields, non‐chromatographic isolation of products, and substrate tolerance (59 examples).