Preparation of new pyrido[3,4-b]thienopyrroles and pyrido[4,3-e]thienopyridazines
作者:Vegar Stockmann、Anne Fiksdahl
DOI:10.1016/j.tet.2008.05.062
日期:2008.8
types of pyrido-fused tris-heterocycles (1a,b and 2a,b) have been prepared from 3-aminopyridine in five/six steps. A synthetic strategy for the preparation of the novel pyrido[3,4-b]thieno[2,3- and 3,2-d]pyrroles (1a,b) and pyrido[4,3-e]thieno[2,3- and 3,2-c]pyridazines (2a,b) has been studied. The Suzuki cross coupling of the appropriate 2- and 3-thienoboronic acids (3,4) and 4-bromo-3-pyridylpivaloylamide
由三氨基吡啶经五,六个步骤制备了两种新型的吡啶基稠合的三杂环(1a,b和2a,b)。一种合成新型吡啶并[3,4- b ]噻吩并[2,3-和3,2- d ]吡咯(1a,b)和吡啶并[4,3- e ]噻吩并[2,3]的合成策略-和3,2- c ]哒嗪(2a,b)已被研究。合适的2-和3- thienoboronic酸(的铃木交叉偶联3,4)和4-溴-3- pyridylpivaloylamide(9),得到二芳基偶联产物(10,11)以高产率(85%)。水解的(2-噻吩基)-偶联产物(12)重氮化和叠氮化物取代,得到3-叠氮基-4-(2-噻吩基)吡啶中间体(72%,14)。通过交换先前的反应顺序来制备3-叠氮基-4-(3-噻吩基)吡啶(15)。所需的β咔啉噻吩类似物(1A,b)通过叠氮基前体(热分解经由氮烯得到的14,15)。通过优化分子内重氮偶联的条件,可以得到相应的哒嗪产物(72–83%,2a,b)。