A mild method for the formation and in situ reaction of imidoyl chlorides: Conversion of pyridine-1-oxides to 2-aminopyridine amides

[GRAPHICS] A mild, practical, one-pot method for the generation of imidoyl chlorides and their subsequent in situ reaction with pyridine-1-oxides is described. The imidoyl chlorides were formed from the reaction of secondary amides with a stoichiometric amount of oxalyl chloride and 2,6-lutidine in CH2Cl2 at 0degreesC. Upon warming of the reaction mixture to room temperature in the presence of pyridine-1-oxides, a rapid conversion to 2-aminopyridine amides was observed in moderate to excellent isolated yields.