Methyl iodide → 2,4-Dichloro-6-methoxybenzaldehyde

To a stirred solution of 2,4-dichloro-6-hydroxybenzaldehyde (1.85 g, 9.69 mmol) in N,N-dimethylformamide (20 mL) at ambient temperature was added solid potassium carbonate (1.47 g, 10.7 mmol), and the resulting yellow mixture was stirred at ambient temperature for 30 minutes. Iodomethane (2.42 mL, 38.7 mmol) was added, and the resulting mixture was stirred in an oil bath set to 50° C. for 30 minutes. The mixture was cooled to ambient temperature and diluted with water (200 mL). After stirring for 10 minutes, the precipitate that formed was collected by filtration, washed with water, and dried under vacuum to afford 2,4-dichloro-6-methoxybenzaldehyde as an off-white powder (1.93 g, 97% yield).