合成路线1

The reaction of 3-tetrahydrofuroic acid (I) with diphenyl phosphoryl azide (DPPA) in refluxing dioxane gave the intermediate isocyanate (II), which was treated with benzyl alcohol (III) to yield carbamate (IV). Subsequent hydrogenolysis in the presence of Pd/C afforded racemic amine (V), which was resolved by treatment with S-(+)-10-camphorsulfonyl chloride (VI) in pyridine, followed by column chromatography and recrystallization from acetone of the resulting sulfonamide (VII). Then, hydrolysis in HCl-AcOH provided the S-amine (VIII). Condensation of amine (VIII) with 6-chloropurine riboside (IX) in the presence of triethylamine in refluxing MeOH furnished the title compound.