Halogenation

$$\text{C}_6\text{H}_5\text{--OCH}_3 + \text{Br}_2 \xrightarrow{\text{CH}_3\text{COOH}} p\text{--}\text{bromoanisole (90\%, Major)} + o\text{--}\text{bromoanisole (Minor)} + \text{HBr}$$

Concept: Anisole (methoxybenzene) undergoes electrophilic aromatic substitution ($$S_E\text{Ar}$$ ) with bromine in ethanoic acid (acetic acid). The methoxy group ($$\text{--OCH}_3$$ ) strongly activates the aromatic ring through resonance ($$+M$$ effect) and directs incoming electrophiles to the ortho and para positions. Because of this activation, halogenation occurs smoothly without needing a Lewis acid catalyst such as $$\text{FeBr}_3$$ ).