Gabriel synthesis is used for the preparation of

Options

A. Primary amines
B. Primary alcohols
C. Tertiary amines
D. Tertiary alcohols

Answer

**Step-by-Step Solution:**

1. **Understanding Gabriel Synthesis:**
Gabriel synthesis is a method used to prepare primary amines from phthalimide. The key reactant in this synthesis is phthalimide, which has the structure:
\[ \text{Phthalimide: } C_6H_4(CO)_2N \]

2. **Reaction with KOH:**
When phthalimide reacts with potassium hydroxide (KOH), it undergoes hydrolysis. During this reaction, a water molecule is eliminated:
\[ \text{Phthalimide} + KOH \rightarrow \text{Potassium phthalimide} + H_2O \]
The structure of potassium phthalimide can be represented as:
\[ C_6H_4(CO)_2N^-(K^+) \]

3. **Alkyl Halide Reaction:**
The potassium phthalimide then reacts with an alkyl halide (RX). In this step, the nucleophilic nitrogen attacks the alkyl halide, leading to the formation of a new bond and the release of potassium halide (KX):
\[ \text{Potassium phthalimide} + RX \rightarrow \text{N-alkyl phthalimide} + KX \]
The structure of the N-alkyl phthalimide is:
\[ C_6H_4(CO)_2N(R) \]

4. **Hydrolysis to Form Primary Amine:**
The N-alkyl phthalimide is then treated with sodium hydroxide (NaOH), which hydrolyzes the phthalimide ring, resulting in the formation of a primary amine (RNH2) and sodium phthalate:
\[ \text{N-alkyl phthalimide} + NaOH \rightarrow RNH_2 + \text{Sodium phthalate} \]

5. **Final Product:**
The final product of Gabriel synthesis is a primary amine (RNH2). Therefore, we conclude that Gabriel synthesis is used for the preparation of primary amines.

**Answer: Primary amines.**

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