SYNTHESIS OF METHYL-BETA-D-GLYCERO-PENT-2-ENOFURANOSYL)THYMINE, Y-4-C-METHYL-BETA-D-GLYCERO-PENTOFURANOSYL)THYMINE AND METHYL-2-DEOXY-BETA-D-THREO-PENTOFURANOSYL)THYMINE

Reaction of isopropylidene derivative I with thionyl chloride in hexam ethylphosphoric triamide afforded chloro derivative II. Removal of the isopropylidene group in II by treatment with a cation-exchanging resi n (H+ form) gave the free chloro nucleoside III. Reduction of the chlo ro derivative II with tributylstannane and subsequent removal of the i sopropylidene group yielded deoxy derivative V. This was protected wit h tert-butyldiphenylsilyl group and converted into the mesylate VII. E limination of the mesyl group followed by desilylation gave -methyl-be ta-D-glycero-pent-2-enofuranosyl)thymine (IX) which was hydrogenated t o afford y-4-C-methyl-beta-D-glycero-pentofuranosyl)thymine (X). methy l-2-deoxy-beta-D-threo-pentofuranosyl)thymine (XIII) was prepared by m esylation of isopropylidene derivative 1, nucleophilic substitution of the mesyl group with azide and removal of the isopropylidene group.