A practical, efficient, and rapid method for the oxidation of electron deficient pyridines using trifluoroacetic anhydride and hydrogen peroxide–urea complex

A general method for the oxidation of electron-poor pyridines to their N-oxides using UHP and TFAA in either CH2Cl2 or CH3CN was developed. The methodology proved to tolerate a number of functional groups and substitution patterns and proceeded on notoriously difficult to oxidize substrates.