Which of the following will not show Hoffmann bromide reaction?

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds will not show the Hofmann bromamide reaction, we first need to understand the reaction itself. The Hofmann bromamide reaction involves the conversion of an amide to a primary amine with one carbon atom less, using bromine (Br2) in the presence of a base (usually NaOH).

### Step-by-Step Solution:

1. **Identify the Reaction**: The Hofmann bromamide reaction requires an amide as a starting material. The general reaction can be represented as:
\[ RCONH_2 + Br_2 + 2NaOH \rightarrow RNH_2 + Na_2CO_3 + 2NaBr + H_2O \]
Here, RCONH2 is the amide, and RNH2 is the resulting primary amine.

2. **Analyze Each Option**:
- **Option 1**: A compound with a benzene ring and a carbonyl group (C=O) attached to a methyl group (CH3). This is not an amide, so it cannot undergo the Hofmann bromamide reaction.
- **Option 2**: A compound with a benzene ring and a carbonyl group attached to a chlorine atom (C=O, Cl). This can be converted to an amide by reacting with ammonia (NH3), and thus can undergo the Hofmann bromamide reaction.
- **Option 3**: A compound with a carbonyl group (C=O) directly attached to an amine group (NH2). This is a straightforward amide and will undergo the Hofmann bromamide reaction.
- **Option 4**: A compound with a cyano group (C≡N). This can be hydrolyzed to form an amide (CONH2), which can then react with Br2 and NaOH to undergo the Hofmann bromamide reaction.

3. **Conclusion**: Since option 1 does not contain an amide functional group, it will not show the Hofmann bromamide reaction.

### Final Answer:
**Option 1** will not show the Hofmann bromamide reaction.

---