5-Bromopyrimidine-2-carboxylic acid (3.22 g, 15.9 mmol) was dissolved in methanol (50 mL) at room temperature and acetyl chloride (4.0 mL, 56.3 mmol) was slowly added. The reaction mixture was heated to reflux, maintained for 15 min and then cooled to room temperature. Subsequently, the reaction mixture was concentrated under reduced pressure to remove the solvent. The concentrated mixture was diluted with saturated sodium bicarbonate solution (30 mL) and ethyl acetate and transferred to a partition funnel for separation. The aqueous phase was extracted repeatedly with ethyl acetate (4 x 30 mL) and all organic phases were combined. The organic phase was washed with saturated brine (1 × 30 mL), dried over anhydrous magnesium sulfate, filtered and concentrated to give methyl 5-bromo-2-pyrimidinecarboxylate (2.30 g, 10.6 mmol, 67% yield) as a white solid. Analyzed by LC/MS (ESI), m/z = 216.9 ([M+H]+) was measured, which is consistent with the calculated value of molecular weight 216.0 for C6H5BrN2O2.
