One-pot synthesis of 2-substituted thieno[3,2-b]indoles from 3-aminothiophene-2-carboxylates through in situ generated 3-aminothiophenes
作者:Roman A. Irgashev、Alexander S. Steparuk、Gennady L. Rusinov
DOI:10.1016/j.tetlet.2019.151185
日期:2019.10
with arylhydrazines in glacial acetic acid solution. The latter step includes in situ decarboxylation of the freed 3-aminothiophene-2-caboxylic acids to the 3-aminothiophenes and their acid promoted reaction with arylhydrazines to initially form arylhydrazones of 5-substituted thiophene-3(2H)-ones, which smoothly cause indolization to afford the desired thieno[3,2-b]indoles.
一种方便的协议,可使用易于获得的5-取代的3-氨基噻吩-2-羧酸酯一锅合成噻吩并[3,2- b ]吲哚,在C-2位带有芳香,噻吩-2-基或苯乙烯基片段Fischer吲哚化反应是在这项研究期间开发的。该方法的两个主要步骤是用氢氧化钠对起始的3-氨基酯进行皂化,然后在冰醋酸溶液中用芳基肼对粗制的3-氨基酸钠盐进行下一步处理。后面的步骤包括将游离的3-氨基噻吩-2-羧酸原位脱羧为3-氨基噻吩,并使其与芳基肼的酸促进反应,最初形成5-取代噻吩-3(2 H的芳基hydr))-平滑地导致吲哚化以提供所需的噻吩并[3,2- b ]吲哚。