2-Pyridones synthesis, acetic anhydride

Another synthesis of halopyridines, unique to pyridine and other JV-containing heteroarenes, involves transformation of pyridine N-oxide into the corresponding pyridone followed by halogenation. In one case, treatment of 3-chloro-2,4 -bipyridine-l -oxide (8) with acetic anhydride produced the pyridone, which was then converted to dichloride 9 with POCls/DMF [7]. 

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