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0 °C

A mixture of 1,3-dimethylbarbituric acid (5.00 g, 32.05 mmol), dichloroacetic acid (6.19 g, 48.03 mmol), 4-dimethylaminopyridine (1.95 g, 16.01 mmol) in dry CH2Cl2 (30 ml) was cooled to 0° C. and 1,3-dicyclohexylcarbodiimide (7.26 g, 35.22 mmol) added. The reaction mixture was stirred at room temperature overnight and filtered. The solid was washed with CH2Cl2 (150 ml) and the combined solution was washed with 2 N HCl solution (40 ml). The organic phase was dried over MgSO4 and evaporated. The residue was crystallised from MeOH giving 5-dichloroacetyl-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione 7 (5.41 g, 63%).

1. filtrationfiltered
2. washThe solid was washed with CH2Cl2 (150 ml)
3. washthe combined solution was washed with 2 N HCl solution (40 ml)
4. dry with materialThe organic phase was dried over MgSO4
5. customevaporated
6. customThe residue was crystallised from MeOH