Trimethylsilyl triflate → [(1S)-1-[(2S,4R,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-methyl-tetrahydrofuran-2-yl]propyl] benzoate

Participants

Reaction Conditions

Reaction Steps

To a suspension of 5-amino-3,6-dihydrothiazolo[4,5-d]pyrimidine-2,7-dione (872 mg, 4.7 mmol) in ACN (20 mL) was added BSA (913.5 mg, 4.5 mmol). The resulting reaction mixture was then stirred at 70° C. under argon for 2 hours to form a clear solution. After the solution was cooled to room temperature, [(1S)-1-[(2S,4R)-5-acetoxy-4-methyl-tetrahydrofuran-2-yl]propyl] benzoate (compound 28j, 294 mg, 0.95 mmol) and TMSOTf (1.44 g, 6.6 mmol) were added in sequence. After being stirred with stirring at 20° C. for 14 hrs, 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 (30 mL) twice. The combined organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo. The residue was purified and separated by preparative HPLC to afford 9.7 mg of [(1S)-1-[(2S,4R,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-methyl-tetrahydrofuran-2-yl]propyl] benzoate (compound 28k-A) and 8.4 mg of [(1R)-1-[(2S,4R,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-methyl-tetrahydrofuran-2-yl]propyl] benzoate (compound 28k-B) as white solid.

Provenance & Evidence