Direct bromination of aniline with bromine water gives 2,4,6-tribromoaniline, but aniline can be converted into mainly 4-bromoaniline by first making acetanilide. The reason is that

Aacetylation removes the nitrogen atom from the ring
Bthe acetamido group is a meta-directing group
Cthe lone pair on nitrogen is delocalised towards the carbonyl group in $- NHCOCH X_{3}$ , so the ring is less activated
Dacetanilide is more basic than aniline

Answer: C

In acetanilide the N lone pair is shared with the C=O group and is less available to the ring, so

- NHCOCH X_{3}

is still ortho/para directing but only moderately activating. Bromination then stops at the mono stage, mainly at the less hindered para position. Hydrolysis then gives 4-bromoaniline.

Practice Amines and Aromatic Nitrogen Compounds More on Reactions of amines: acylation, carbylamine, Hinsberg test

Previous questionNext question

Direct bromination of aniline with bromine water gives 2,4,6-tribromoaniline, but aniline can be converted into mainly 4-bromoaniline by first making acetanilide. The reason is that

Answer: C

More questions on Reactions of amines: acylation, carbylamine, Hinsberg test