FIELD: organic chemistry, nucleosides, chemical technology. SUBSTANCE: invention proposes a method of synthesis of nucleoside corresponding to the structure (A) 
where A is O; X is S; Z1, Z2, Z3, R1, R2 and R3 mean H; R4 means H or lower alkyl. Compound of the structure (B) 
where B1, B2 and B3 mean blocking groups or lower alkyl and L means +CN is subjected for interaction with the structure (C) 
where XY is SH and R4 means lower alkyl. As result L-structure of (B) converts to the structure (D) 
comprising heterocyclic ring which is aromatized then for a single stage. When L means C(S)-NH2 then the compound of the structure (B) is added to reaction with ethylbromopyruvate/NaHCO3. and synthesized nucleoside is subjected then the reaction to yield thiazofurine. EFFECT: increased yield of product, decreased time of process. 11 cl, 3 dwg, 11 ex
