The chemistry of polyazaheterocyclic compounds. Part VIII. Coupling reactions of 1,2,4-triazole-5-diazonium nitrate with active methylene compounds. A new general route to [1,2,4]triazolo[5,1-c][1,2,4]triazine derivatives

Abstract

1,2,4-Triazole-5-diazonium nitrate couples with a variety of active methylene compounds (diethyl malonate, ethyl benzoylacetate, acetylacetone, benzoylmacetone, dibenzoylmethane, and benzoylacetonitrile) at room temperature in the presence of sodium acetate of afford 1,2,4-triazol-5-ylhydrazones, which are smoothyl converted in warm aqueous ethanolic sodium acetate or glacial acetic acid, in high yield, into the corresponding [1,2,4]triazolo[5,1-c][1,2,4]triazine derivatives. In the cases of ethyl acetoacetate and cyanoacetamide the derived hydrazones were unstable and underwent spontaneous cyclisation even at room temperature, affording the corresponding triazolotriazines.