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 mechanism of this reaction and the types of amines that can be produced.

### Step-by-Step Solution:

1. **Understanding Gabriel Phthalimide Synthesis**:
- Gabriel phthalimide synthesis is a method used to prepare primary amines. It involves the use of phthalimide, which is a cyclic imide, and a strong base (like KOH) to generate a nucleophilic species that can react with alkyl halides.

2. **Reaction Mechanism**:
- The phthalimide reacts with a strong base to form a phthalimide anion. This anion can then undergo nucleophilic substitution with an alkyl halide (R-X) to form a substituted phthalimide.
- After the substitution, the product can be hydrolyzed (usually with NaOH) to yield the primary amine and phthalic acid.

3. **Identifying the Types of Amines Formed**:
- The synthesis can produce primary amines from aliphatic alkyl halides. However, it cannot produce aryl amines from aryl halides because aryl halides do not undergo nucleophilic substitution reactions effectively.

4. **Analyzing the Given Compounds**:
- We need to look at the options provided (not listed in the question) and identify which one is an aryl amine.
- If any of the options is an aryl amine (where the amine group is directly attached to a benzene ring), it cannot be formed by Gabriel phthalimide synthesis.

5. **Conclusion**:
- The compound that cannot be formed by Gabriel phthalimide synthesis is the one that is an aryl amine.

### Final Answer:
- The compound that cannot be formed by Gabriel phthalimide synthesis is the aryl amine.