Question

Identify the final product formed when Benzamide undergoes the following reactions:

• A. Acetanilide
• B. Acetophenone
• C. Aniline
• D. Benzoic acid

Hint:

Hofmann rearrangement is a reaction in which an amide undergoes a cleavage to form a primary amine. The product formed in the second step depends on the acylation of the amine.

Answer 1

The Correct Option is A

The given reaction involves Benzamide, which reacts with \( \text{Br}_2 \) and \( \text{KOH} \) in the presence of heat (\( \Delta \)) to form the intermediate product [X], which further reacts with \( (CH_3CO)_2O \) and Pyridine to form the final product [Y]. 1.
Step 1: Reaction of Benzamide with \( \text{Br}_2 / \text{KOH} \)
- When Benzamide reacts with Bromine (\( \text{Br}_2 \)) and Potassium Hydroxide (\( \text{KOH} \)) under heating, it undergoes a Hofmann rearrangement. - In Hofmann rearrangement, an amide is converted into a primary amine by the removal of the carbonyl group (\( \text{-C=O} \)). The reaction can be represented as: \[ \text{C}_6\text{H}_5\text{CONH}_2 \xrightarrow{\text{Br}_2/\text{KOH}, \Delta} \text{C}_6\text{H}_5\text{NH}_2 \] Thus, the intermediate product [X] is Aniline. 2.
Step 2: Reaction of Aniline with \( (CH_3CO)_2O \) and Pyridine
- Aniline reacts with acetic anhydride (\( (CH_3CO)_2O \)) in the presence of Pyridine to form an amide, specifically Acetanilide. The reaction is: \[ \text{C}_6\text{H}_5\text{NH}_2 + (CH_3CO)_2O \xrightarrow{\text{Pyridine}} \text{C}_6\text{H}_5\text{NHCOCH}_3 \] Thus, the final product [Y] is Acetanilide. Hence, the final product formed is Acetanilide.