Abstract The pyrido [2, 3-e]-as-triazine and its 3-phenyl derivatives were prepared via cyclisation with polyphosphoric acid of suitable 3-substituted 2-aminopyridines obtained by reduction of the corresponding 2-nitropyridines. The 3-substituted 2-nitropyridines were obtained by action of hydrazine or benzoylhydrazide with the appropriate 3-halo-2- nitropyridines; only 3-fluoro-2-nitropyridine leads to the 3-substituted 2-nitropyridines. This ...