Hoffmann bromomide degradation of benzamide gives product A, which upon heating with \(\mathrm{CHCl}_{3}\) and NaOH gives product \(B\). The structures of \(A\) and \(B\) are:

(A) A - (see structure) B - (see structure)

(B) A - (see structure) B - (see structure)

(C) A - (see structure) B - (see structure)

(D) A - (see structure) B - (see structure)

JEE Main · 2021 · 17 Mar 2021 · Shift 1 · Compounds Containing Nitrogen

Hoffmann bromomide degradation of benzamide gives product A, which upon heating with

CHCl_{3}

and NaOH gives product

B

.
The structures of

A

and

B

are:

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

Answer: (A)

Solution

Hofmann bromamide degradation converts an amide into a primary amine with one carbon less, so benzamide gives aniline. A primary amine warmed with chloroform and sodium hydroxide undergoes the carbylamine reaction: the hydroxide generates dichlorocarbene from

CHC l_{3}

, the nitrogen lone pair captures it, and two eliminations of HCl leave an isocyanide. A is aniline,

C_{6} H_{5} N H_{2}

, and B is phenyl isocyanide,

C_{6} H_{5} NC

JEE Main · 2021 · 17 Mar 2021 · Shift 1 · Single correct option

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JEE Main · 2021 · 17 Mar 2021 · Shift 1 · Compounds Containing Nitrogen

Solution

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