The mass spectra of nitrogen heterocycles—I: The mass spectra of nitraminopyridines and a nitriminopyridine

Mass spectra of nitraminopyridines can be obtained by careful introduction of the sample direct to the ion source. Electron-impact fragmentation of the molecular ion is largely by expulsion of nitrogen dioxide. Introduction of samples through a heated glass inlet results in extensive pyrolysis with formation of nitric oxide, nitrous oxide and ions corresponding to an aminopyridine. In addition, the 2-nitraminopyridines give strong ions for the corresponding pyridones and ions at high mass resulting from an undefined bimolecular reaction. Similarly in the direct inlet spectrum of N-methyl-2-nitriminopyridine loss of nitrogen dioxide is the only significant reaction of the parent ion but the heated inlet causes extensive pyrolysis. This is largely restricted to expulsion of nitrous oxide with formation of N-methylpyridone.