Dimethyl Sulfate → 3-Fluoro-2-methoxybenzaldehyde

To a suspension of 3-fluoro-2-hydroxybenzaldehyde (5.328 g, 38.02 mmol) and potassium carbonate (7.88 g, 57.03 mmol) in acetone (60 mL) was added dimethyl sulphate (3.96 mL, 41.83 mmol). The resulting suspension was stirred at 60° C. for 2 h before being allowed to cool and then concentrated in vacuo. The residue was dissolved in dichloromethane (100 mL) and water (50 mL). The organic phase was washed with saturated sodium bicarbonate (50 mL) with the resulting organic phase being dried (MgSO4) and the solvent evaporated in vacuo to give a pale yellow oil (6.262 g, 38.02 mmol, 100%). δH (300 MHz, CDCl3) 10.40 (1H, s, CHO), 7.60 (1H, d, Ar), 7.30 (1H), m, Ar), 7.10 (1H, m, Ar), 4.10 (3H, s, OCH3).