General procedure for the synthesis of methyl 2-fluoro-5-bromonicotinate from 2-fluoro-5-bromonicotinic acid and iodomethane: 0.75 mL (12 mmol) of iodomethane and 2.5 g (18 mmol) of potassium carbonate were added to a solution of 2.0 g (9.1 mmol) of 5-bromo-2-fluoronicotinic acid in DMF (8 mL). The reaction mixture was stirred at room temperature for 20 hours. After the reaction was completed, water was added to the reaction mixture and then extracted with ethyl acetate. The organic layer was washed with water and dried with anhydrous magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure and purified by silica gel column chromatography (elution solvent: hexane/ethyl acetate) to afford methyl 2-fluoro-5-bromonicotinate 1.7 g (7.3 mmol, 80% yield) as a white solid. Mass spectra (CI, m/z): 234, 236 [M + 1]+. 1H-NMR spectrum (400 MHz, DMSO-d6) δ: 8.66 (dd, J = 1.3, 2.6 Hz, 1H), 8.56 (dd, J = 2.6, 8.2 Hz, 1H), 3.89 (s, 3H).
