反应详情

3.4 g of 1,3-dimethyl-7-(6-bromohexyl)-xanthine are boiled overnight under reflux in 50 ml of glacial acetic acid to which 1 ml of acetic anhydride and 5 g of potassium acetate have been added. After evaporation of the solvent by distillation in vacuo the residue is dissolved in 50 ml of 5% sulfuric acid on the addition of 20 ml methanol. The solution is boiled under reflux for 1 hour. The mixture is extracted with chloroform. The chloroform phase is washed until it is neutral and concentrated in vacuo. 1,3-dimethyl-7-(6-hydroxyhexyl)-xanthine having a melting point of 80° C. is obtained in a yield of more than 90%.

1. additionhave been added
2. customAfter evaporation of the solvent
3. distillationby distillation in vacuo the residue
4. dissolutionis dissolved in 50 ml of 5% sulfuric acid on the addition of 20 ml methanol
5. temperatureunder reflux for 1 hour
6. extractionThe mixture is extracted with chloroform
7. washThe chloroform phase is washed until it
8. concentrationconcentrated in vacuo