Which one of the following can be prepared by Gabriel phthalimide synthesis?

Options

A. Aniline
B. o-Toluidine
C. 4-Bromoaniline
D. N-Methylethanamine.

Explanation

To solve the question regarding which compound can be prepared by Gabriel phthalimide synthesis, we need to understand the mechanism and the products of this synthesis. Here’s a step-by-step breakdown of the process:

### Step 1: Understanding Gabriel Phthalimide Synthesis
Gabriel phthalimide synthesis is a method used to prepare primary amines. The synthesis involves the use of phthalimide, which reacts with a base (usually KOH) and an alkyl halide.

### Step 2: Reaction Mechanism
1. **Formation of Phthalimide Anion**:
- Phthalimide (C6H4(CO)2NH) is treated with a strong base like KOH, which deprotonates the nitrogen, forming a phthalimide anion.
- This anion is nucleophilic and can react with alkyl halides.

2. **Alkylation**:
- The phthalimide anion attacks an alkyl halide (R-X), where R is the alkyl group and X is the halide (like Cl, Br, etc.).
- This results in the formation of an N-alkyl phthalimide.

3. **Hydrolysis**:
- The N-alkyl phthalimide is then hydrolyzed using water and an acid (H2O, H+).
- This hydrolysis breaks the phthalimide ring and releases the primary amine (RNH2) along with phthalic acid.

### Step 3: Identifying the Products
The primary amine produced from this reaction is aliphatic. The options given in the question need to be evaluated based on whether they are primary amines and if they are aliphatic.

### Step 4: Evaluating the Options
1. **Aniline**: This is an aromatic amine (C6H5NH2) and cannot be produced by Gabriel synthesis.
2. **Ortho-toluidine**: This is also an aromatic amine (C6H4(CH3)NH2) and cannot be produced by Gabriel synthesis.
3. **N-methylethanamine**: This is a secondary amine (R2NH) and cannot be produced by Gabriel synthesis as it produces primary amines.
4. **4-bromoaniline**: This is an aromatic amine (C6H4BrNH2) and cannot be produced by Gabriel synthesis.

### Conclusion
Among the options provided, none of them are suitable for preparation via Gabriel phthalimide synthesis as they are either aromatic or secondary amines. However, if we consider the context of the question, the correct answer would be the option that represents a primary aliphatic amine, which is not explicitly listed in the options given.

### Final Answer
None of the provided options can be prepared by Gabriel phthalimide synthesis as they are not primary aliphatic amines.