The general procedure for the synthesis of 2-bromo-4-hydroxybenzaldehyde from ethanol and m-bromophenol was as follows: 30% aqueous sodium hydroxide solution (160 mL) was mixed with 3-bromophenol (10.04 g, 58 mmol) and heated to 70-75 °C. Subsequently, ethanol (5 mL) was added all at once and chloroform (28 mL, 0.35 mol) was added slowly and dropwise. After maintaining the reaction at 75 °C for 1 hour, the reaction mixture was continued to be stirred at this temperature for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and acidified with 10N hydrochloric acid. Most of the by-products were removed by steam distillation. The residue was cooled and the precipitate was separated by filtration. The crude product was purified by silica gel column chromatography using hexane/ethyl acetate (2:1, v/v) as eluent to give 1.75 g of 2-bromo-4-hydroxybenzaldehyde in 15% yield.
