Synthesis of New [1,2,4]triazolo[1,5-a]pyridine Derivatives by Reaction Pyridine- 2-(1H)-ones and Aldehydes in the Presence of Acetic Acid as a Green Catalyst and Solvent

Pyridines have been reported as biologically interesting molecules and precursors for thesynthesis of triazolo[1,5-a]pyridines [1]. Triazolopyridines constitute an important class ofheteroatomic compounds and frequently found in a variety of biologically active compoundssuch as antithrombotic, anti-inflammatory and antiproliferative agents [2]. Several methodshave previously described for the synthesis of triazolo[1,5-a]pyridines [3]. In the presentinvestigation the synthesis of some novel substituted triazolo[1,5-a]pyridines are attemptedfor their expected useful biological properties. New 1,2,4-triazolo[1,5-a]pyridine derivativeshave been synthesis in high yields in the presence of acetic acid as both solvent and catalyst at70 °C with the reaction of pyridine-2-(1H)-one derivatives and aldehydes. The Brϕnsted acidnature of acetic acid, promotes reaction by involving in both nucelophilic addition as well asin dehydration steps. Chemical structure of all molecules were characterized by spectroscopyand elemental analysis. The procedure offers several advantages, including green conditions,a simple work-up procedure, excellent yields and short reaction times.