反应详情

9.7 Grams (0.06 moles) of bromine were added to a solution of 15 g (0.054 moles) of 7-(5-keto-hexyl)-1,3-dimethylxanthine in 100 ml of anhydrous methanol, at 10° C. with stirring. After 30 minutes at the same temperature, stirring was continued for 7 more hours at room temperature. The mixture was then concentrated under reduced pressure till a residual volume of 30 ml, diluted with 30 ml of water, added with 3 drops of 96% sulphuric acid and stirred for 4 hours at room temperature, to hydrolyze any dimethylketal formed, then diluted with 100 ml of water and alkalized with a 10% sodium bicarbonte aqueous solution. The mixture was extracted with 2×80 ml of methylene chloride, the organic phase was washed with water, dried and evaporated under reduced pressure. The residue was dissolved in 30 ml of ethyl acetate, cooled and crystallized at 5°-10° C. 7.5 Grams (40%) of the title compound were obtained, melting at 106°-109° C., which was directly used in the next step.

1. stirringstirring
2. customwas continued for 7 more hours at room temperature
3. concentrationThe mixture was then concentrated under reduced pressure till a residual volume of 30 ml
4. additiondiluted with 30 ml of water
5. additionadded with 3 drops of 96% sulphuric acid
6. stirringstirred for 4 hours at room temperature
7. customformed
8. extractionThe mixture was extracted with 2×80 ml of methylene chloride
9. washthe organic phase was washed with water
10. customdried
11. customevaporated under reduced pressure
12. dissolutionThe residue was dissolved in 30 ml of ethyl acetate
13. temperaturecooled
14. customcrystallized at 5°-10° C