Heteroarenium salts in synthesis. Highly functionalized tetra- and pentasubstituted pyridines
作者:Andreas Schmidt、Thorsten Mordhorst、Martin Nieger
DOI:10.1016/j.tet.2005.11.065
日期:2006.2
Activation of chloropyridines by heteroarenium substituents allows sequential substitutions by O-, N-, and S-nucleophiles. Reaction of 2,3,5,6-tetrachloropyridine and 4-ethylsulfanyl-2,3,5,6-tetrachloropyridine with 4-(dimethylamino)pyridine, 4-(pyrrolidin-1-yl)pyridine, or 4-aminopyridine results in the formation of 2,6-bis-heteroarenium substituted 3,5-dichloropyridines. On nucleophilic displacement of the heteroarenium substituents by O-, N-, or S-nucleophiles highly functionalized 3,5-dichloropyridines form which possess N-2,S-4 N-6-, O-2,S-4,O-6-, O-2, O-6-, N-2 N-6-, and S-2,S-6- substitution patterns. (c) 2005 Elsevier Ltd. All rights reserved.