Bromine → 1-Bromo-4-methoxy-2,5-dimethylbenzene

Bromine (291.5 g, 1835 mmol) was added dropwise while stirring to an initially charged mixture of 2,5-dimethylanisole (250 g, 1835 mmol) and Fe powder (3.25 g). The commencement of the reaction could be recognized by gas evolution. The remaining bromine was then added dropwise at room temperature over a period of 30-40 minutes while cooling on a water bath. The reaction mixture was stirred further for about 4 hours. The solution was then separated from the Fe powder, a little chloroform was added and the mixture was shaken with water, which led to the solution becoming lighter in color. After shaking with 50 ml of saturated aqueous Na2SO3 solution, the solution had become completely decolorized. It was then shaken again with dilute aqueous NaOH and twice with H2O and, after drying, the solvent was taken off. The crude product was fractionally distilled under reduced pressure.