Synthesis of 10-phenyl-[1,2,4]Triazolo[1,5- b ] [2,7]Naphthyridin-5(3 H )-One Derivatives

Several new 10-phenyl-[1,2,4]triazolo[1,5- b][2,7]naphthyridin-5(3 H)-one derivatives were synthesised by condensation of 2,3-diamino-4-phenyl-2,7-naphthyridin-1(2 H)-one with aldehydes and also with acid anhydrides. Their structures were confirmed by 1 H NMR, 13 C NMR, IR, mass spectra and elemental analysis. The key starting material 4-[a-cyano(phenyl)methyl]nicotinic acid was easily cyclised to give 3-amino-4-phenyl-1 H-pyrano[3,4- c]pyridin-1-one under alkaline conditions, the structure of which was confirmed by X-ray crystallography following conversion to the corresponding N,N-dimethylformamidine derivative.