Oxidative aromatization of 4,7-dihydro-6-nitroazolo[1,5-a] pyrimidines: Synthetic possibilities and limitations, mechanism of destruction, and the theoretical and experimental substantiation

Abstract

The reaction tolerance of the multicomponent process between 3-aminoazoles, 1-morpholino2-nitroalkenes, and aldehydes was studied. The main patterns of this reaction have been established. Conditions for the oxidation of 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines were selected. Previous claims that the 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines could not be aromatised have now been refuted. Compounds with an electron-donor substituent at position seven undergo decomposition during oxidation. The phenomenon was explained based on experimental data, electro-chemical experiment, and quantum-chemical calculation. The mechanism of oxidative degradation has been proposed.