3,3′- and 4,4′-Dimethoxy-2,2′-bipyrroles: Highly Electron-Rich Model Compounds for Polypyrrole Formation.
作者:Andreas Merz、Sergiy Anikin、Bernd Lieser、Jürgen Heinze、Hermann John
DOI:10.1002/chem.200390047
日期:2003.1.20
3,3'-Dimethoxy-2,2'-bipyrrole (1) and 4,4'-dimethoxy-2,2'-bipyrrole (2) were obtained in short sequences and good yields from N-benzyl-3-hydroxypyrrole-2,4-dicarboxylic acid. The key intermediate leading to 1 is an N-benzyl-3-methoxypyrrole, which is dimerized by lithiation and oxidation with NiCl(2). The formation of 2 is achieved by a classical Ullmann coupling of diethyl 1-benzyl-2-bromo-4-methoxypyrrole-3
从N-苄基-3-羟基吡咯-得到的3,3'-二甲氧基-2,2'-联吡咯(1)和4,4'-二甲氧基-2,2'-联吡咯(2)以短序列获得且良好的收率。 2,4-二羧酸。导致1的关键中间体是N-苄基-3-甲氧基吡咯,通过锂化和NiCl(2)氧化使其二聚。2的形成是通过1-乙基-2-苄基-2-溴-4-甲氧基吡咯-3,5-二羧酸二乙酯的经典Ullmann偶联实现的。1和2的N-苄基保护基在还原条件下用钠在液态氨中的裂解。两种异构的双吡咯对空气都极为敏感。化合物1相对于AgCl具有0.09V的非常低的氧化电势,但是几乎不发生膜形成。另一方面,电位为0.35V的化合物2容易形成阳极波为-0.51和-0的稳定的聚吡咯膜。