Which of the following compound cannot be formed by Gabriel phthalimide synthesis:

Options

A.
B.
C. `(CH_(3))_(2)CH-NH_(2)`
D. `(C_(2)H_(5))(CH_(3))CH-NH_(2)`

Answer

To determine which compound cannot be formed by Gabriel phthalimide synthesis, we need to understand the process and its limitations. Here’s a step-by-step solution:

### Step 1: Understand Gabriel Phthalimide Synthesis
Gabriel phthalimide synthesis is a method used to prepare primary amines from phthalimide. The process involves the following steps:
1. **Formation of Phthalimide Salt**: Phthalimide is treated with a strong base (like potassium hydroxide) to form a phthalimide salt.
2. **Alkylation**: The phthalimide salt is then alkylated using an alkyl halide. This step introduces the alkyl group to the nitrogen atom.
3. **Hydrolysis**: The resulting N-alkyl phthalimide is then hydrolyzed (usually with aqueous acid) to yield the primary amine.

### Step 2: Identify the Types of Amines
In Gabriel phthalimide synthesis, the types of amines that can be formed include:
- **Primary aliphatic amines**: These can be formed as the nitrogen is attached to an alkyl group.
- **Secondary and tertiary amines**: These cannot be formed directly through this method since the synthesis specifically yields primary amines.

### Step 3: Recognize Limitations
A key limitation of Gabriel phthalimide synthesis is that it cannot produce **aryl amines** (amines where the nitrogen is directly attached to an aromatic ring). This is because aryl halides do not undergo nucleophilic substitution reactions effectively.

### Step 4: Analyze the Given Compounds
Now, let’s analyze the options provided (though not listed here, we assume some common examples):
- If one of the options is an **aryl amine** (e.g., aniline, NH2 attached directly to a benzene ring), it cannot be formed by Gabriel phthalimide synthesis.
- Other options that are **aliphatic amines** or **primary amines** can be formed through this method.

### Conclusion
The compound that cannot be formed by Gabriel phthalimide synthesis is the **aryl amine**.

### Final Answer
The compound that cannot be formed by Gabriel phthalimide synthesis is the aryl amine (e.g., aniline).

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