To a suspension of 2-fluoro-3-methoxybenzoic acid (2.0 g, 11.8 mmol) in dichloromethane (20 mL) and methanol (2 mL) was added slowly and dropwise trimethylmethylsilyl diazomethane (2M ethyl ether solution, 12.3 mmol, 6.2 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 30 min and then the solvent was removed by distillation under reduced pressure. The residue was diluted with ethyl acetate, adsorbed on silica gel and purified by silica gel column chromatography in two batches to give 2.0 g (92% yield) of methyl 2-fluoro-3-methoxybenzoate. The product was characterized by 1H NMR (CDCl3, 400 MHz): δ 7.48-7.44 (m, 1H), 7.15-7.09 (m, 2H), 3.93 (s, 3H), 3.91 (s, 3H).
