反应详情

2.45 g (18.0 mmol) of potassium carbonate were added at 60° C. to a suspension of 3.0 g (11.0 mmol) of 7-benzyl-3-ethylxanthine (prepared according to Example 5a) in 60 ml of dimethylformamide and the mixture was stirred at this temperature for one hour. 1.77 g (14.0 mmol) of sec-butoxymethyl chloride were then added dropwise and the mixture was stirred at 80° C. for 5 hours. 0.7 g (5.5 mmol) of sec-butoxymethyl chloride was then added again and the mixture was stirred for a further 3 hours. 12 ml of water and 5 ml of methanol were then added and the mixture was stirred at 50° C. for 2 hours. A further 60 ml of water were then added, the mixture was extracted three times using 200 ml of methyl tert-butyl ether each time, and the combined organic phases were washed with 200 ml of water, dried using magnesium sulfate and concentrated under reduced pressure. The crude product was purified by flash chromatography on a silica gel column, dichloromethane/methanol (19.8/0.2).

1. stirringthe mixture was stirred at 80° C. for 5 hours
2. stirringthe mixture was stirred for a further 3 hours
3. stirringthe mixture was stirred at 50° C. for 2 hours
4. extractionthe mixture was extracted three times
5. washthe combined organic phases were washed with 200 ml of water
6. customdried
7. concentrationconcentrated under reduced pressure
8. customThe crude product was purified by flash chromatography on a silica gel column, dichloromethane/methanol (19.8/0.2)