The present invention relates to a number of innovative electrophilic substitution reactions involving 2,5-dithienylpyrrole (2,5-DTP). More specifically, these reactions are used in the synthesis of monomers for preparing functionalized conducting organic polymers. The elctrophilic substitution reactions in this invention are accomplished under conditions not requiring the use of N-1 pyrrole blocking groups to direction reaction at the pyrrole C-3 position. This is because the steric bulk of the 2,5-dithienyl groups prevent N-acylation and therefore direct reactions with electrophiles at the pyrrole C-3 position. The reaction conditions chosen have also demonstrated a greater regioselectively towards functionalization at the pyrrole 3-position than the basic reaction conditions suggested in the prior art. This result may be explained by an activation of the pyrrole 3-position towards electrophilic substitution. This is attributed to an electron donating resonance contribution of the 2,5 thienyl groups. Other advantageous reaction conditions have been discovered which direct electrophilic substitution preferentially at the pyrrole or thiophene groups depending upon the amount of acidic catalyst.
本发明涉及一系列涉及2,5-二
噻吩基
吡咯(2,5-DTP)的创新亲电取代反应。更具体地说,这些反应用于合成用于制备功能化导电有机聚合物的单体。本发明中的亲电取代反应在无需使用N-1
吡咯阻断基的条件下完成,以在
吡咯C-3位置上直接反应。这是因为2,5-二
噻吩基团的立体位阻止了N-酰化,因此直接与
吡咯C-3位置的亲电试剂发生反应。所选择的反应条件还表现出比先前文献中建议的基本反应条件更高的对
吡咯3-位置进行官能团化的区域选择性。这一结果可以通过激活
吡咯3-位置对亲电取代进行解释。这归因于2,5-二
噻吩基团的电子给予共振贡献。还发现了其他有利的反应条件,根据酸性催化剂的量,这些条件优先引导亲电取代反应在
吡咯或
噻吩基团上进行。