2-Aminopyridines via Reaction of Pyridine N-Oxides and Activated Isocyanides

A practical and efficient method for the synthesis of substituted 2-aminopyridines from pyridine N-oxides is reported. Yields of purified, isolated products of up to 84% are observed for the one-pot, two-step process. The reaction involves an in situ deprotection of an isolable N-formylaminopyridine intermediate and facilitates the synthesis of 2-aminopyridines for which other methods fail.