Synthesis of nitrogen‐containing heterocycles. 4. A facile route to new 1, 2, 4‐triazole derivatives

The reaction of amino‐ N (4), N (4)‐dimethylaminornethylenehydrazones 1 of some aliphatic carbonyl compounds with ethyl ethoxymethylenecyanoacetate 2 gave directly symmetrical gem ‐bis(3‐dimethylamino‐1, 2, 4‐triazol‐1‐yl)alkanes 4 and (3‐dimethylamino‐1, 2, 4‐triazol‐1‐yl)alkenes 5 at room temperature, with the former being major product. On the other hand, the reaction of amino‐ N (4)‐methylaminomethylenehydrazone homologue 1 of aliphatic ketone with 2 gave ethyl 2‐alkyl‐5‐methylamino[1, 2, 4]triazolo[1, 5‐ c ]pyrimidine‐8‐carboxylate 7 as the only product with elimination of alkane.