The regioselective acylation reactions of imidazopyridines

Article abstract of DOI:10.3987/com-98-8124

The regioselectivity of acylation in imidazopyridines can be controlled by two mechanism-specific reactions. As expected acylation reactions under Friedel-Crafts conditions result in reaction at the most electron-rich site in imidazopyridines. However, depending on the structure of the imidazopyridine, ylid intermediates are proposed to direct reaction to the electron-deficient site in the parent heterocycles. These observations led to the selective synthesis of acylimidazopyridines and this methodology was used in the preparation of analogs of the α₂-adrenergic agonists MPV-207 and clonidine. 1. This research was conducted at Sterling Winthrop Pharmaceuticals Research Division prior to its acquisition by Sanofi, Inc.