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

Participants

Reaction Conditions

Reaction Steps

To a suspension of 5-amino-3,6-dihydrothiazolo[4,5-d]pyrimidine-2,7-dione (4.42 g, 24.0 mmol) in ACN (20 mL) was added BSA (14.8 mL, 60.0 mmol). The resulting reaction mixture was then stirred at 70° C. under argon for 0.5 hr to form a clear solution. After the solution was cooled to room temperature, [(2S,4R)-4,5-diacetoxytetrahydrofuran-2-yl]methyl benzoate (CAS #: 4613-71-2, Cat.#: MD04725, commercially available from Carbosynth Limited, 6.45 g, 20.0 mmol) and TMSOTf (5.5 mL, 30.0 mmol) were added in sequence. After being heated with stirring at 70° C. for 14 hours, the solvent was removed in vacuo. The residue was partitioned between EtOAc and saturated NaHCO3 solution (30 mL). The organic layer was separated and the aqueous phase was extracted with EtOAc (100 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 to afford 5.7 g of [(2S,4R,5R)-4-acetoxy-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)tetrahydrofuran-2-yl]methyl benzoate (compound 38a) as a light yellow solid.

Provenance & Evidence