Convenient two-step preparation of [1,2,4]triazolo[4,3-a]pyridines from 2-hydrazinopyridine and carboxylic acids
作者:Aline Moulin、Jean Martinez、Jean-Alain Fehrentz
DOI:10.1016/j.tetlet.2006.08.075
日期:2006.10
Triazolopyridines are an important class of biologically active heterocyclic compounds. In this letter, we describe a new method for the synthesis of [1,2,4]triazolo[4,3-a]pyridines starting from 2-hydrazinopyridine and carboxylic acids. The resulting acetohydrazides are cyclized in a key step using the Lawesson’s reagent. The reaction conditions were explored, as well as the scope of this reaction
三唑并吡啶是一类重要的生物活性杂环化合物。在这封信中,我们描述了一种从2-肼基吡啶和羧酸开始合成[1,2,4]三唑并[4,3- a ]吡啶的新方法。使用Lawesson试剂在关键步骤中将生成的乙酰肼进行环化。探索了反应条件以及该反应的范围,涉及三唑并吡啶环的3位上的取代基。我们还证明,在杂环的α位上存在手性碳时,这种杂环化是无消旋作用的。