A short and robust approach for the synthesis of 2-(hetero)aryl substituted thieno[2,3-b]indoles from easily available 1-alkylisatins and acetylated (hetero)arenes has been advanced. The two-step procedure includes the “aldol-crotonic” type of condensation of the starting materials, followed by treatment of the intermediate 3-(2-oxo-2-(hetero)arylethylidene)indolin-2-ones with Lawesson’s reagent. The latter process involves two sequential reactions, namely reduction of the C=C ethylidene double bond of the intermediate indolin-2-ones followed by the Paal–Knorr cyclization, thus affording tricyclic thieno[2,3-b]indoles.
一种简洁而强大的方法用于从易得的1-烷基异
色酮和乙酰化的(杂)
芳烃合成2-(杂)芳基取代的
噻吩[2,3-
b]
吲哚。这种两步法包括起始原料的“醛-
巴豆酸”类型的缩合反应,随后处理中间体3-(2-氧代-2-(杂)芳基
乙烯基亚甲基)
吲哚-2-酮与
劳森试剂。后者的过程涉及两个连续反应,即还原中间体
吲哚-2-酮的C=C
乙烯双键,然后进行Paal-Knorr环化反应,从而得到
三环噻吩[2,3-
b]
吲哚。