Question

Which from following reactions occurs by removal of -CO- group from amide ?

• A. Gabriel phthalimide synthesis
• B. Ammonolysis of halides
• C. Mendius reduction
• D. Hofmann degradation

Hint:

In Hofmann bromamide degradation the amide loses its carbonyl carbon as carbonate.

Answer 1

The Correct Option is D

Step 1: Understand the concept
We need the reaction in which an amide loses its -CO- group. This gives an amine with one carbon less.

Step 2: Hofmann degradation
\(\text{RCONH}_2 + \text{Br}_2 + 4\text{NaOH} \to \text{RNH}_2 + 2\text{NaBr} + \text{Na}_2\text{CO}_3 + 2\text{H}_2\text{O}\). The carbonyl carbon leaves as carbonate, so the amine has one carbon fewer than the amide.

Step 3: Check others
Gabriel synthesis uses a phthalimide anion and an alkyl halide to make a primary amine. Ammonolysis uses ammonia and an alkyl halide. Mendius reduction reduces a nitrile with Na and alcohol. None of these removes a CO group from an amide.

Step 4: Conclusion
Hofmann degradation is the answer.

Final Answer:
Hofmann degradation drops the carbonyl carbon as carbonate. This is option (D). \[ \boxed{\text{(D) }\text{Hofmann degradation}} \]