Pyrimidine derivatives and heterocyclic annulated pyrimidines continue to attract great interest due to the wide variety of interesting biological activities observed for these compounds, such as anticancer [1], antiviral [2], antitumor [3], and anti­inflammatory activities [4]. In this study, 5­bromo­2­chloro­4­hydrazino­6­methyl pyrimidine (1) was synthesized according to our previous method.[5] The treatment of this compound with 2,6­ dicholoropyridazine (2) in pyridine gave quantitatively the desired heterocyclized pyridazino[6,1­ c]pyrimido[5,4­e][1,2,4]triazine derivative as a novel heterocyclic system. Eventually, the reaction of it with various secondary amines obtained new derivatives of pyridazino[6,1­c]pyrimido[5,4­ e][1,2,4]triazine 3(a­e).

Keywords