JEE Chemistry 2023 Question with Solution

Given: The compound is treated with $\mathrm{Br_2/NaOH}$ under $\Delta$.

Find: The structure of product B.

The reaction given involves the treatment of the compound with bromine and sodium hydroxide under heat. This is a classic example of the Hofmann Bromamide Degradation Reaction.

In this reaction, the amide group $-CONH_2$ undergoes degradation to form a primary amine $-NH_2$ with loss of one carbon atom from the amide carbonyl carbon.

The ester group $-COOCH_3$ remains intact during this reaction because it does not participate in the Hofmann bromamide degradation.

Therefore, the major product is the cyclohexanone derivative in which the $-CONH_2$ group is replaced by $-NH_2$ while the $-COOCH_3$ group remains unchanged. Hence, the correct option is D.

Given: Reagent set $\mathrm{Br_2/NaOH,\ \Delta}$.

Find: Which option matches the product formed.

Identify the principle: Hofmann bromamide reaction converts an amide into a primary amine having one carbon less than the parent amide.

Apply to the substrate:

1. The side chain containing $-CONH_2$ is the reactive functional group.
2. Under $\mathrm{Br_2/NaOH}$, this group is transformed to $-NH_2$.
3. The ester functionality $-COOCH_3$ is retained.

Conclude: The product must be the structure consistent with amide-to-amine conversion without disturbing the ester group. Thus, the correct option is D.