8-Bromo-7-ethoxymethyl-3-methylxanthine (prepared as described for CT12440) (3.03 g, 10 mmol) was added to a suspension of sodium hydride (264 mg, 11 mmol) in anhydrous dimethylsulfoxide (60 ml). After stirring for 30 minutes, (R) 5-acetoxy-1-chlorohexane (1.963 g, 11 mmol) was added and the mixture was heated at 70-80° C. for 12 hours. After cooling to room temperature, the reaction was quenched by the addition of water (150 ml) and extracted with 10% methanol-ethyl acetate (3x 25 ml). The combined extracts were washed with water (2x 50 ml), with saturated aqueous sodium chloride solution (50 ml), dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel eluting with 30% ethyl acetate-hexane to provide (R)-1-(5-acetoxyhexyl)-8-bromo-7-ethoxymethyl-3-methylxanthine (2.778).
