General procedure for the synthesis of 2,6-dibromo-4-tert-butylphenol and 2-bromo-4-tert-butylphenol from 4-tert-butylphenol: A solution of 4-tert-butylphenol (ca. 10 mmol) and p-toluenesulfonic acid (pTsOH, 10 mol%) in methanol (MeOH, 1.0 mL/mmol of raw material) was stirred for 10 min. Subsequently, a methanol solution (0.1 M) of N-bromosuccinimide (NBS, 100 mol%, recrystallized from H2O) was added dropwise from a foil reaction flask over 20 min. The reaction mixture was continued to be stirred for 5 min and then concentrated in vacuum. The resulting residue was purified by column chromatography with the eluent being dichloromethane (CH2Cl2) or a dichloromethane solution containing 1% methanol. Product characterization: 2-bromo-4-methylphenol (10) [23]: 10.1 mmol; 1.73 g (92% yield).
