26305-13-5

1780-32-1

General procedure for the synthesis of 2,4-dichloro-5,6-dimethylpyrimidine from 5,6-dimethyluracil: A mixture of 5,6-dimethyluracil (4.00 g, 28.5 mmol), phosphorochloride (60 mL, 0.642 mol), and dimethylformamide (0.08 mL, 1.03 mmol) was heated and refluxed for 23 hours at 110 °C. Upon completion of the reaction, the reaction mixture was cooled to room temperature and evaporated. Toluene (80 mL) was added to the residue and the mixture was subsequently concentrated. Cold water (160 mL) containing ice was added to the residue and the mixture was extracted with chloroform (3 x 60 mL). The organic layers were combined, washed with brine (2 x 150 mL), dried over anhydrous sodium sulfate, filtered and concentrated to give 2,4-dichloro-5,6-dimethylpyrimidine as a light yellow solid (4.37 g, 87% yield). The melting point of the product was 68-70 °C. 1H NMR (400 MHz, CDCl3) δ 2.55 (s, 3H), 2.34 (s, 3H). lRMS (ESI+) m/z 177.1.