The nitration of 2-amino-4,6-dimethylpyridine with a mixture of nitric and sulphuric acids gives 4,6-dimethyl-2-nitramino-5-nitropyridine (III). 2-Nitraminopyridine (I), 4-methyl-2-nitraminopyridine (II), and (III) produce with diazomethane methyl derivatives of their tautomeric nitramino and nitrimino forms. Diazoethane gives with (I) both the expected ethyl derivatives. However, from (II) only the ethyl derivative of the nitramino form has been obtained. Diazopropane produces with (I) or (II) the propyl derivatives of the nitramino forms only. The resonance structures of the two tautomeric forms of 2-nitraminopyridine have been advanced.