The reaction between 2-hydrazinopyridines and ethyl imidates was examined as a one-pot method for rapidly preparing [1,2,4]triazolo[4,3-a]pyridines. A diverse set of 2-hydrazinopyridines were cyclized with a variety of alkyl- and aryl-substituted ethyl imidates in good yields. The reaction proceeds optimally under mild conditions (50−70 °C) using 1.5 equiv of acetic acid. The electronic and steric
作为快速制备[1,2,4]三唑并[4,3- a ]
吡啶的一锅法,研究了2-
肼基
吡啶和
酰亚胺乙酯之间的反应。用各种烷基取代基和芳基取代的乙基
酰亚胺酯以高收率将各种不同的2-
肼基
吡啶环化。使用1.5当量的
乙酸,在温和的条件下(50-70°C),反应可以最佳地进行。
肼和亚
氨酸酯的电子和位阻性质强烈影响反应速率。当使用高度缺乏电子的2-
肼基
吡啶时,产物重排为[1,2,4]三唑并[1,5- a ]
吡啶。