Theophylline → 1,3-dimethyl-7-propyl-2,3,6,7-tetrahydro-1H-purine-2,6-dione

Temperatur

90 °C

600 g of theophylline (a product of Katayama Kagaku Kogyo K.K.) was dissolved in 180 ml of an aqueous solution containing 263.4 g of potassium hydroxide, and the solution was evaporated to dryness under reduced pressure to prepare a potassium salt of theophylline. The resulting salt was suspended in 3600 ml of dimethylformamide, and 436.5 ml of propyl bromide was added thereto, followed by heating at 90° C. for 8 hours while stirring. Dimethylformamide was removed by distillation under reduced pressure, and to the residue was added 1800 ml of dichloromethane. The mixture was washed three times with 300 ml portions of a 1N potassium hydroxide aqueous solution and then once with 300 ml of water and dried over 54 g of anhydrous magnesium sulfate. The desiccant was removed by filtration, and the mother liquor was dried under reduced pressure and then in vacuo (85° C., 5 hours) to obtain 657 g (yield: 88.8%) of 1,3-dimethyl-7-propylxanthine.

1. customthe solution was evaporated to dryness under reduced pressure
2. customto prepare a potassium salt of theophylline
3. customDimethylformamide was removed by distillation under reduced pressure
4. additionto the residue was added 1800 ml of dichloromethane
5. washThe mixture was washed three times with 300 ml portions of a 1N potassium hydroxide aqueous solution
6. dry with materialonce with 300 ml of water and dried over 54 g of anhydrous magnesium sulfate
7. customThe desiccant was removed by filtration
8. customthe mother liquor was dried under reduced pressure

ORD-Eintrag

ord-d9948330e7fe4da3b5491515a30445ae

Quelldatensatz

uspto-grants-1996_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05550041