Nucleophilic substitution of 4-(dimethylamino) pyridine on pentachloropyridine yielded pentakis (pyridine-2, 3, 4, 5, 6-pentayl) pyridinium, tris-(3, 5-dichloropyridine-2, 4, 6-triyl) pyridinium, or (tetrachloropyridin-4-yl) pyridinium depending on the reaction conditions. Nucleophilic substitution with water, hydroxides, and alcoholates resulted in new betaines and highly substituted pyridines.
[Chambers, Richard D.; Khalil, Ali; Murray, Christopher B.; Sandford, Graham; Batsanov, Andrei S.; Howard, Judith A.K. Journal of Fluorine Chemistry, 2005 , vol. 126, # 7 p. 1002 - 1008]