The Application Of The New Tandem Reaction In The Synthesis Of[1,2,4] Triazolo [1,5-a] Pyridine Compounds

The [1,2,4]triazolo[1,5-a]pyridines are a kind of very important heterocyclic compounds which exist in many natural products. It is known that this kind of compounds have a variety of pharmacological activities, such as insecticidal, anti-inflammatory, antitumor, microbicides and anti-bacterial and relaxing blood vessels and other effects. For that reason, it achieves extensive attention from chemists.At the moment, only a few methods used to synthesize[1,2,4]triazolo[1,5-a]-pyridines are known. What’s more, most of those methods are from pyridines to synthesize aim compounds, which have many boundedness such as the operation is complex, the reaction condition is harsh and the yield is low. Therefore, it is very meaningful to explore a novel and effective synthetic method.We recently discovered a new efficient tandem reaction for the synthesis of nitrogen bridgehead compounds. The synthetic utility of this reaction has been demonstrated by its successful application in the synthesis of pyrazolo[l,5-a]pyridines, imidazo[1,2-a]pyridines, pyrido[1,2-a]benzimidazoles and [1,2,4]triazolo[1,5-a]pyridine. For that reason, we reckon that it may be a good idea to synthesize [1.2,4]triazolo[1,5-a]pyridines by using this tandem reaction.This tandem reaction proceed by an intermolecular SN2reaction, deprotonation, and then electron pair transfer, cyclization, followed by elimination to form the desired final products.By using this tandem reaction and changing the intermediates, we synthesized21new derivatives of [1,2,4]triazolo[1,5-a]pyridine in total.