(2R,3R,4S,5R)-2-{2-[(Benzylsulfanyl)methyl]-6-[(2,2-diphenylethyl)amino]-9H-purin-9-yl}-5-(methoxymethyl)tetrahydro-3,4-furandiol (100 mg, 0.17 mmol) (example 76) was dissolved in stirred acetone (3 ml) and solid sodium hydrogen carbonate (100 mg, 1.2 mmol) added. A solution of Oxone (trade mark) (potassium peroxymonosulphate) (410 mg, 0.68 mmol) dissolved in water (2 ml) was then added dropwise to the original solution over the course of 30 min. Dichloromethane (2 ml) was also added and the reaction mixture stirred at room temperature for 60 hr. The reaction mixture was then diluted with ethyl acetate (100 ml) and water (50 ml). The organic layer was separated, dried with anhydrous magnesium sulfate and the solvent removed under reduced pressure to give a residue which was purified by column chromatography on silica gel eluting with a solvent gradient of ethyl acetate:hexane (4:1) increasing in polarity to ethyl acetate:methanol (96:4). This gave the title compound (50 mg) as a gum. MS: 630 (MH+).
