Question

Give plausible explanation for each of the following:
Aromatic primary amines cannot be prepared by Gabriel Phthalimide synthesis.

Hint:

Aromatic rings are less reactive in nucleophilic substitution reactions due to the resonance stabilization of the ring.

Answer 1

Gabriel Phthalimide synthesis involves the reaction of phthalimide with an alkyl halide to form an amine. This method works well for aliphatic amines but fails for aromatic primary amines because the reaction does not readily occur with aryl halides. Aromatic rings are generally less reactive in nucleophilic substitution reactions due to the resonance stabilization of the ring, which makes it harder for the nucleophile (amide ion) to attack. Hence, Gabriel’s synthesis does not work efficiently for preparing aromatic primary amines.