反应详情

温度

50 °C

Sodium (356 mg, 15.5 mmol) was carefully added to ethanol (5.9 mL) to prepare sodium ethoxide solution in ethanol. The above freshly prepared sodium ethoxide in ethanol solution (3.5 mL) was added to a stirred suspension of acetamidine hydrochloride (0.91 g, 9.69 mmol). The mixture was warmed to 50° C., then the heating bath was removed and a solution of mucobromic acid (1 g, 3.87 mmol) in ethanol was added dropwise at a rate which maintained a constant temperature, followed by a further sodium ethoxide in ethanol solution (2 mL). After cooling, the mixture was filtered and evaporated to a residue which was shaken vigorously with hydrochloric acid (2 M×2.4 mL). The brown precipitate was filtered and washed with cold water, then freeze-dried to give 5-bromo-2-methylpyrimidine-4-carboxylic acid (350 mg, 42%) as a brown solid. LCMS: 218 [M+1]+, 1H NMR (400 MHz, DMSO-d6): δ 2.62 (s, 3H), 9.03 (s, 1H).

1. customthe heating bath was removed
2. temperaturemaintained a constant temperature
3. temperatureAfter cooling
4. filtrationthe mixture was filtered
5. customevaporated to a residue which
6. filtrationThe brown precipitate was filtered
7. washwashed with cold water
8. customfreeze-dried