Bromine → (3-Bromo-4-methylsulfanyl-phenyl)-acetic acid methyl ester

A solution of (4-methylsulfanyl-phenyl)-acetic acid methyl ester (7.28 g, 37.1 mmol) in carbon tetrachloride (150 mL) was slowly treated with bromine (2.5 mL, 48.23 mmol). The reaction mixture was stirred at 25° C. for 3 h, at which time, thin layer chromatography still indicated the presence of a substantial amount of starting material. The reaction mixture was treated with more bromine (2.5 mL, 48.23 mmol). The reaction mixture was stirred an additional 1 h at 25° C. and then quenched with a 10% aqueous sodium bisulfite solution (200 mL). The reaction mixture was concentrated in vacuo to remove carbon tetrachloride. The resulting aqueous layer was extracted with ethyl acetate (3×200 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70-230 mesh, 9/1 hexanes/ethyl acetate) afforded (3-bromo-4-methylsulfanyl-phenyl)-acetic acid methyl ester (8.57 g, 84%) as a light yellow oil: EI-HRMS m/e calcd for C10H11BrO2S (M+) 273.9663, found 273.9661.