A solution of 1-(9-decenyl)-3,7-dimethylxanthine (CT1563) (3.2g, 10.1 mmol), 4-methylmorpholine-N-oxide (1.41 g, 12 mmol) and 2.5% osmium tetraoxide in t-butanol (3 drops) in acetone (40 ml) and water (10 ml) was stirred for 24 hr. After the addition of saturated sodium dithionite solution (5 ml) the mixture was stirred for 15 min. The mixture was extracted with 25% ethanol-dichloromethane (4×50 ml). The combined organic layers were dried over sodium sulfate and the solvents were evaporated under vacuum to a give solid which was recrystallized (ethanol) to give 1-(9,10-dihydroxydecyl)-3,7-dimethylxanthine (CT1564) (3.30 g, 93% yield).
