Cyclic Guanidines; IV.<sup>1</sup>Intramolecular Nucleophilic Aromatic Substitution of Hydrogen in (3-Nitrophenyl)guanidines
作者:Franz Esser、Karl-Heinz Pook
DOI:10.1055/s-1992-26172
日期:——
Cyclization of substituted (3-nitrophenyl)guanidines is achieved in basic medium by nucleophilic displacement of hydrogen. The reaction offers a new route to benzimidazoles as well as to tricyclic imidazo-, pyrimido- and diazepino-benzimidazoles with uncommon substitution patterns. The mechanism of the redox process is investigated and the regioselectivity is discussed in terms of substrate structure and reaction conditions. An outline is given on the scope of the ring closure.
取代的(3-硝基苯基)酸酰胺在碱性介质中通过亲核取代氢进行环化反应。该反应提供了一条合成苯并咪唑的新途径,以及合成具有不寻常取代图案的三环咪唑、吡啶和二氮杂并苯并咪唑的方法。研究了该还原氧化过程的机制,并从底物结构和反应条件的角度讨论了区域选择性。文中还概述了环闭合的范围。