Preparation of New Nitrogen-Bridged Heterocycles. XXXIII. A New Preparative Method for Thieno(3,2-a)indolizines.
作者:Akikazu KAKEHI、Suketaka ITO、Tatsuya UEDA、Satoshi TAKANO
DOI:10.1248/cpb.41.1753
日期:——
The treatment of 2-iminothieno[3, 2-α]indolizine derivatives with potassium tert-butoxide generated exclusively potassium 1-(2-cyanovinyl)indolizine-2-thiolates through the ring opening of the initially formed thiin-2-imide ions. These 2-indolizinethiolates reacted with various alkylating agents to give the corresponding S-alkylated 1-vinylindolizine derivatives, and 2-acetonylthio- and 2-phenacylthio-1-(2-cyanovinyl)indolizines of these products smoothly underwent intramolecular Michael addition under the conditions employed here to afford the corresponding 2-acetyl- and 2-aroylthieno[3, 2-α]indolizines in high yields with the elimination of a methylene compound.
用叔丁醇钾处理 2-亚氨噻吩并[3, 2-α]吲嗪衍生物,通过最初形成的硫-2-亚胺离子的开环作用,生成了 1-(2-氰基乙烯基)吲嗪-2-硫醇钾。这些 2-吲哚乙硫酸盐与各种烷化剂反应,生成相应的 S-烷基化 1-乙烯基吲嗪衍生物,这些产物中的 2-乙酰硫基和 2-苯乙酰硫基-1-(2-氰基乙烯基)吲嗪在本文采用的条件下顺利进行分子内迈克尔加成,以高产率得到相应的 2-乙酰基和 2-芳酰基噻吩并[3, 2-α]吲嗪,同时消除了一个亚甲基化合物。