Acetic Anhydride → 3,8-Dimethyl-3,7-dihydro-1H-purine-2,6-dione
Reaction equation
[NH2:1][C:2]1[C:3](=[O:11])[NH:4][C:5](=[O:10])[N:6]([CH3:9])[C:7]=1[NH2:8].[C:12](OC(=O)C)(=O)[CH3:13]>>[CH3:9][N:6]1[C:7]2[N:8]=[C:12]([CH3:13])[NH:1][C:2]=2[C:3](=[O:11])[NH:4][C:5]1=[O:10]Participants
3
Procedure
A solution of 5,6-diamino-1-methyluracil (2.5 g) in acetic anhydride (25 ml) was heated at reflux for 2 hours and then the acetic anhydride was evaporated under reduced pressure. The residue was dissolved in 10% aqueous sodium hydroxide solution (50 ml) and heated at reflux for 2 hours. After cooling to room temperature, the mixture was acidified to pH 4 by addition of concentrated hydrochloric acid. The precipitate was filtered, washed with water (15 ml), rinsed with acetone (15 ml) and dried under vacuum to provide 3,8-dimethylxanthine (1.8 g).
Workup
- temperatureat reflux for 2 hours
- customthe acetic anhydride was evaporated under reduced pressure
- dissolutionThe residue was dissolved in 10% aqueous sodium hydroxide solution (50 ml)