Acetic Anhydride → 5-Acetyl-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione

Participants

Reaction Conditions

Reaction Steps

A mixture of 1,3-dimethylbarbituric acid (10 g, 64.04 mmol), 4-dimethylaminopyridine (9.49 g, 158.0 mmol) in dry CH2Cl2 (190 ml) was cooled to 0° C. and acetic anhydride (7.35 ml, 77.9 mmol) added dropwise in 15 min. The reaction mixture was stirred overnight at room temperature, diluted with CH2Cl2 (500 ml) and washed with 2 N HCl solution (80 ml). The organic phase was dried over MgSO4 and evaporated. The residue was crystallised from MeOH, giving 5-acetyl-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione 1 (8.6 g, 68%).

Provenance & Evidence