Access to azolopyrimidine-6,7-diamines as a valuable “building-blocks” to develop new fused heteroaromatic systems

A simple and convenient approach for the synthesis of new azolopyrimidine-6,7-diamines has been developed by the method of reductive cleavage of azo-group in series 6-[2-(4-methylphenyl)diazenyl]azolo[1,5-a]pyrimidine-7-amines, which was obtained by the interaction of aminoazoles with [2-(4-methylphenyl)hydrazinylidene]-3-oxo-propionitrile. The proposed approach allows to use a wide range of aminoazoles as a starting reagent and it also distinguishes itself by the simplicity of isolation and purification of products. The synthetic potential of presented diamines was demonstrated by the reaction of obtaining azolo[a]annulated pteridines. [Display omitted]