Chapter 22, Problem 50P

Interpretation Introduction

Interpretation:

The preparation of $\text{2-(2-bromophenyl)ethanamine}$ by the Gabriel amine synthesis from $\text{N-potassiophthalimide}$ and compound A is to be shown.

Concept Introduction:

Gabriel synthesis is used to prepare primary amines with no side products like secondary and tertiary amines.

The reaction starts with the potassium salt of phthalimide. It has a nucleophilic nitrogen atom having a negative charge.

The potassium salt of phthalimide reacts with a primary alkyl halide by the ${\text{S}}_{\text{N}}\text{2}$ type of mechanism. The product formed is an imide.

Further reaction hydrazine forms the required primary amine.

Aryl halides do not react by this method since nucleophilic substitution does not take place on aromatic rings. This method is not useful to prepare aryl amines.