Synthesis and reactions of 1,6-diaryl-2,5-bis(diazo)-1,3,4,6-tetraoxohexanes

Abstract

The title compounds were obtained in about 50% yields by reaction of the corresponding diaryltetraoxohexanes with dinitrogen trioxide. A mechanism to account for their formation is proposed. Thermal decompositions of bis-diazo-compounds in the solid state or in suspension in various media afforded derivatives of α,α′-diaroylsuccinic acids (6) and, in one case, a pyrazole. Ketens are postulated as intermediates. In an inert medium, a bis-keten is suggested to react in tramolecularly to give the bis-enol-lactone of (6); its structure was established by X-ray crystallography. This bis-enol-lactone was shown to be formed by pyrolysis of diesters of (6), contrary to earlier reports.