Synthesis of new pyrido[4,3-e][1,2,4]triazolo-[5,1-c][1,2,4]triazin-6(7H)-ones

Coupling of 3-substituted 1,2,4-triazole-5-diazonium salts with ethyl acetoacetate afforded 1,2,4-triazol-5-ylhydrazones, the reaction of which with dimethylformamide dimethyl acetal leads to the formation of the corresponding readily separable 4-[2-(dimethylamino)-vinyl][1,2,4]triazolo[5,1- c ][1,2,4]triazine-3-carboxylates. New pyrido[4,3- e ][1,2,4]triazolo[5,1- c ][1,2,4]triazin-6(7 H )-ones were synthesized by the condensation of the latter with primary amines.