Schmidt Andreas, Mordhorst Thorsten, Nieger Martin
Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany.
Org Biomol Chem. 2005 Oct 21;3(20):3788-93. doi: 10.1039/b510627c. Epub 2005 Sep 14.
Nucleophilic substitutions on pentachloropyridine with 4-(dimethylamino)pyridine, 4-aminopyridine, and 4-(pyrrolidin-1-yl)pyridine give mono-, tri- and pentacationic pyridine-hetarenium salts. The mono-, tri- and pentacationic 4-aminopyridine derivatives can be deprotonated to neutral compounds in solution, or protonated to di-, hexa- and decacationic pyridine derivatives, respectively. Successive substitutions with different heteroaromatic nucleophiles give pyridines with two distinct types of heteroarenium substituents.
五氯吡啶与4-（二甲基氨基）吡啶、4-氨基吡啶和4-（吡咯烷-1-基）吡啶发生亲核取代反应，生成单阳离子、三阳离子和五阳离子吡啶 - 杂芳鎓盐。单阳离子、三阳离子和五阳离子4-氨基吡啶衍生物在溶液中可以去质子化成为中性化合物，或者分别质子化成为二阳离子、六阳离子和十阳离子吡啶衍生物。用不同的杂芳族亲核试剂进行连续取代，可得到带有两种不同类型杂芳鎓取代基的吡啶。
