A method for the synthesis of a new 4-phenylsulfonyl-substituted 3-aminopyrrole was developed and related pyrrolo[3,2-d]pyrimidine derivatives were synthesized.The 3-aminopirrole derivatives are known to possess antibacterial, anticonvulsant, antiphlogistic, analgesic and antipyretic activity [1][2][3][4]. Therefore, the synthesis of new biologically active 3-aminopyrrole derivatives is a relevant task. In our work we succeeded to synthesize a new compound of this class which contains a phenylsulfonyl group in position 4 of the pyrrole fragment that is important for the creation of drugs with antiviral activity [5] belonging to this class of compounds. As the starting reagent we used enaminonitrile I (Scheme 1) that had been synthesized previously [6]. In its reaction with chloroacetonitrile in the presence of K 2 CO 3 , obviously, the alkylation product II is initially formed. The latter was not isolated in individual state, as the reaction proceeds with intramolecular cyclization involving the nitrile and active methylene groups and leading to the formation of tetrasubstituted pyrazole III in 43% yield (Table 1) [7][8][9]. Structure of III was proved reliably by the complex spectral study (Table 2).Since compound III contains a nitrile and a primary amine groups at the neighboring carbon atoms of the ring, we used it for fusion of a pyrimidine fragment. Like in other studies [10,11], we used dimethylformamide dimethylacetal as a one-carbon com-