Rearrangement pyridine nitramines

Nitration of pyridines via rearrangement of nitramines has been studied. 4-Amino-3-bromopyridine forms, with nitric acid, the nitramine 9.67 in 85% yield 9.67 rearranges in sulfuric acid to 4-amino-3-bromo-5-nitro-pyridine (9.68) in 97% yield (62RC967). The rearrangement of 2-nitrami-no-4-nitropyridine (9.69) to 2-amino-3,4-dinitropyridine is accompanied by the formation of 4-nitro-2-pyridone (64T81), subsequently shown to arise via nitrosation (79T2895). 

Nitramine rearrangements occur in quinoline , pyridine , and thiazole derivatives, and although migration into both rings is reported for the first type, studies in the pyridine series indicate an intramolecular pathway . Thermal and photochemical reactions of iV-nitroanilines and naphthylamines give 30 to 50% yields of... 

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