申请人:Miles Inc.
公开号:US05068355A1
公开(公告)日:1991-11-26
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 electrophilic substitution reactions in this invention are accomplished under conditions not requiring the use of N-1 pyrrole blocking groups to direct 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 regioselectivity 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.
本发明涉及一些创新的亲电取代反应,涉及2,5-二噻吩基吡咯(2,5-DTP)。更具体地说,这些反应用于合成单体,以制备功能化导电有机聚合物。本发明中的亲电取代反应在不需要使用N-1吡咯阻断基来引导在吡咯C-3位置的反应的条件下完成。这是因为2,5-二噻吩基的立体体积防止了N-酰化,因此直接与亲电体在吡咯C-3位置反应。所选择的反应条件还表现出比先前技术建议的基本反应条件更高的对在吡咯3位的官能团化的区域选择性。这个结果可能是由于2,5-噻吩基的电子供体共振贡献激活了吡咯3位对亲电取代的反应。这归因于2,5-噻吩基的电子供体共振贡献。还发现了其他有利的反应条件,可以根据酸性催化剂的数量有选择地将亲电取代引导到吡咯或噻吩基。