METHOD OF SYNTHESIS OF 2',3'-DIDEOXY-3'-THIACYTYDINE OR 2',3'- -DIDEOXY-3'-THIA-5-FLUOROCYTIDINE, NUCLEOSIDE ENRICHED WITH ENANTIOMER, METHOD OF SYNTHESIS OF 1,3-OXATHIOLANE, METHOD OF SYNTHESIS OF 2-ACYLOXY-5-ACYLOXY-1,3-OXATHIOLANE ENRICHED WITH ENANTIOMER, ENANTIOMERS, METHOD OF CLEAVAGE OF NUCLEOSIDE ENANTIOMERS Russian patent published in 1999 - IPC

FIELD: organic chemistry, virology. SUBSTANCE: invention relates to methods of synthesis and compositions for producing antiviral nucleoside analogs, in part, 2',3'-dideoxy- -3'-thiacytidine (BCH-189). BCH-189 and 2', 3'-dideoxy-3'-thia- -5-fluorocytidine are synthesized mainly by interaction of 1,3-oxathiolane of the formula (I) β- where R - hydroprotective group and R' - acyl group with a base taken from a group involving silylated cytosine or 5-fluorocytosine in the presence of SnCl₄. This synthesis way provides stereoselective producing biologically active isomer of β--BCH-189 and related compounds. Moreover, stereochemistry at position 4 of nucleoside can be controlled for producing -BCH-189 enriched with enantiomer and its analogs. EFFECT: improved method of synthesis. 27 cl, 4 dwg