105603-49-4

67-56-1

72517-15-8

105603-49-4

General procedure for the synthesis of methyl 5-bromo-2,3-dihydroxybenzoate from methanol and 5-bromo-2,3-dihydroxybenzoic acid: firstly, thionyl chloride (0.35 mL, 4.8 mmol) was mixed with methanol (5.4 mL) and stirred at room temperature for 30 min. Subsequently, 5-bromo-2,3-dihydroxybenzoic acid (600 mg, 2.57 mmol) was added to the mixture. The reaction mixture was continued to be stirred at room temperature for 2 hours and then heated to reflux for 7 hours. After completion of the reaction, the mixture was cooled and concentrated to give a brown solid. Finally, purification by column chromatography (using a 2.5 cm × 25 cm column with an eluent ratio of 1:4 ethyl acetate/hexane, which was subsequently adjusted to 1:1 ethyl acetate/hexane) afforded the target product methyl 5-bromo-2,3-dihydroxybenzoate (500 mg, 78% yield).