反应详情

437.2 g of 3-methyl-7-propylxanthine are suspended in a mixture of 240 g of methanol and 321 g of water and induced to dissolve at elevated temperature with 160 g of 50% strength sodium hydroxide solution, and subsequently at the boiling point 358 g of 1-bromo-5-hexanone are added and the mixture is heated to reflux for 41/2 hours. After cooling, unreacted 3-methyl-7-propylxanthine is separated off and the alcohol is removed by distillation. The aqueous solution is adjusted to pH 11 with sodium hydroxide solution and extracted with methylene chloride. 1-(5-Oxohexyl)-3-methyl-7-propylxanthine is obtained with melting point 69°-70° C. in approximately 90% yield (based on reacted 3-methyl-7-propylxanthine) from the residue of the methylene chloride solution after recrystallization from 5.2 of diisopropyl ether.

1. temperaturethe mixture is heated
2. temperatureto reflux for 41/2 hours
3. temperatureAfter cooling
4. customunreacted 3-methyl-7-propylxanthine is separated off
5. customthe alcohol is removed by distillation
6. extractionextracted with methylene chloride