Synthesis of 6-imino-5-tetrahydro-1H-2-pyrrolylidenhexahydro-2,4-pyrimidinediones as intermediates for the synthesis of C-azanucleosides

The method for the synthesis of 6-imino-5-tetrahydro-1H-2-pyrrolylidenhexahydro-2,4-pyrimidinediones is described. It is shown that the reaction of phosphorus trichloride, 2-pyrrolidones and 6-aminopyrimidines brings to condensation producing 6-imino-5-tetrahydro-1H-2-pyrrolylidenhexahydro-2,4-pyrimidinediones as intermediates for the synthesis of C-azanucleosides. The reaction of 6-imino-1,3-dimethyl-5-tetrahydro-2-pyrrolylidenhexahydro-2,4-pyrimidinedione with benzoyl chloride produces 10-benzoyl-2,4-dimethyl-6-phenyl-1,2,3,4,8,9-hexahydropyrimido[5,4-e]pyrrolo[1,2-c]pyrimidine-1,3-dione. A method for the selective reduction of the carbomethoxy group of methyl 5-(4-imino-1,3-dimethyl-2,6-dioxohexahydro-5-pyrimidinyliden)-2-pyrrolidine carboxylate by system NaBH4/1,4dioxane/CoCl2/PEG-400 is described.