Trimethylsilyl triflate → [[(2S,4R,5R)-4-acetoxy-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)tetrahydrofuran-2-yl]-cyclopentyl-methyl] benzoate

Participants

Reaction Conditions

Reaction Steps

To a suspension of 5-amino-3,6-dihydrothiazolo[4,5-d]pyrimidine-2,7-dione (370 mg, 2.0 mmol) in ACN (20 mL) was added BSA (2.1 g, 10 mmol). The resulting reaction mixture was then stirred at 70° C. for 0.5 hour under argon to form a clear solution. After the solution was cooled to room temperature, [cyclopentyl-[(2S,4R)-4,5-diacetoxytetrahydrofuran-2-yl]methyl] benzoate (compound 11c, 400 mg, 1.0 mmol) and TMSOTf (2.25 g, 10 mmol) were added in sequence. After being heated with stirring at 70° C. for 14 hours, the solvent was evaporated in vacuo. The residue was partitioned between EtOAc and saturated NaHCO3 solution (30 mL). The organic layer was collected and the aqueous phase was extracted with EtOAc (30 mL) twice. The combined organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 1:1 EtOAc in petroleum ether) to afford 160 mg of [[(2S,4R,5R)-4-acetoxy-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)tetrahydrofuran-2-yl]-cyclopentyl-methyl] benzoate (compound 11d).

Provenance & Evidence