Dimethylformamide → Methyl 4-bromo-3-fluorobenzeneacetate

To a mixture of 2-(4-bromo-3-fluorophenyl)acetic acid (5 g, 21.46 mmol) in MeOH (50 mL) was added SOCl2 (1.879 mL, 25.7 mmol) and DMF (0.166 mL, 2.146 mmol). Then the mixture was stirred at 80° C. for 16 h. The mixture was concentrated and extracted with EA (100 mL×2) and washed with NaHCO3 (100 mL) to give the organic layer. The combined organic extract was washed with brine, dried over Na2SO4, filtered, and concentrated to yield a brown oil of methyl 2-(4-bromo-3-fluorophenyl)acetate (5 g, 17.20 mmol, 80% yield): 1H NMR (400 MHz, MeOH-d4) δ 7.53 (t, J=7.6 Hz, 1H), 7.15 (dd, J=1.6, 9.6 Hz, 1H), 7.04-6.99 (m, 1H), 3.67 (s, 3H), 3.65 (s, 2H); ES-LCMS m/z 249.0 (M+H+2).