Triacetoxyperiodinane → 1-[(2S,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-oxo-tetrahydrofuran-2-yl]propyl acetate

To a stirred solution of 1-[(2S,4R,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-hydroxy-tetrahydrofuran-2-yl]propyl acetate (compound 22a, 2.8 g, 7.6 mmol) in THF (100 mL) was added Dess-Martine periodinane (4.8 g, 11.3 mmol). After being stirred at room temperature for 2 hours, the resulting solution was filtered and the filtrate was concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 1:10 methanol in DCM) to afford 2.8 g crude product of 1-[(2S,5R)-5-(5-amino-2,7-dioxo-6H-thiazolo[4,5-d]pyrimidin-3-yl)-4-oxo-tetrahydrofuran-2-yl]propyl acetate (compound 22b). MS obsd. (ESI−) [(M−H)−]: 367.