Mass spectrometry of nitrogen heterocycles. 3. Thermal intramolecular cyclization of 2-azolylaminopyridines

Mass spectrometric fragmentation or decay of 2-azolylaminopyridines containing a carbonyl group in the ortho-position results in elimination of a neutral molecule (ammonia, ethanol, hydrogen sulfide). This decay process is accompanied by intramolecular cyclization to form an ion with a triazolo[1,5-a]pyrido[2,3-d]pyrimidine structure.For Communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 101–104, January, 1991.