JEE Main · 2021 · 22 Jul 2021 · Shift 2 · Hydrocarbons

Which one of the following reactions does not occur?

(A)(see structure)
✓ Correct
(B)(see structure)
(C)(see structure)
(D)(see structure)

Answer: (A)

Solution

All four changes start from aniline. Nitration with nitric and sulphuric acid, acetylation of the amino group with acetic anhydride, and sulphonation with sulphuric acid all proceed. Friedel-Crafts alkylation fails because the nitrogen lone pair of aniline coordinates to the Lewis acid

AlC l_{3}

; the nitrogen then bears a positive charge, becomes strongly deactivating towards an incoming electrophile, and the ring does not react. The change that does not occur is the Friedel-Crafts methylation of aniline to 4-methylaniline.

JEE Main · 2021 · 22 Jul 2021 · Shift 2 · Single correct option

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