Synthesis of -enantiomers of 4′-thioarabinofuranosyl pyrimidine nucleosides

-Enantiomers of 4′-thioarabinofuranosyl pyrimidine nucleosides were synthesized from -xylose. Methyl 6 was converted to the corresponding xylitol 7, which was treated with MsCl and then Na2S to give 1,4-anhydro- -4-thioarabitol 8. As previously reported, Pummerer rearrangement of 8 followed by glycosylation with a silylated thymine and N4-acetylcytosine derivative and deprotection gave the corresponding α- and β- -4′-thioarabinofuranosyl pyrimidine nucleosides.