[Synthesis]
Preparation of compound 4-chloro-5,6-dimethoxypyrimidine: 4,6-dichloro-5-methoxypyrimidine (300 mg, 1.68 mmol) was dissolved in methanol (10 mL), followed by cooling of the reaction mixture to 0 °C. Under stirring, sodium methanolate (99 mg, 1.85 mmol) was slowly added, and after addition, the reaction mixture was allowed to gradually warm up to room temperature. The reaction mixture was stirred continuously for 19 hours at room temperature. After completion of the reaction, methanol was removed by distillation under reduced pressure. The resulting residue was diluted with ethyl acetate and washed sequentially with saturated aqueous sodium bicarbonate solution, aqueous ammonium chloride solution and brine. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with 0 to 10% ethyl acetate/hexane as eluent to give 4-chloro-5,6-dimethoxypyrimidine as a white solid (168 mg, 57% yield). Physical Properties: Melting point 53-55°C. NMR data: 1H NMR (400 MHz, CDCl3) δ 8.27 (s, 1H), 4.03 (s, 3H), 3.88 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 163.6, 151.6, 151.3, 138.2, 60.7, 54.8. |