4.2.2 Gabriel Synthesis

Gabriel method provides an effective route for the synthesis primary amine. In this reaction, phthalimide, having an acidic N-H group, reacts with base to afford a nitrogen containing anion that, as a nucleophile, undergoes substitution on alkyl halides. The resulting compound on hydrolysis with alkali gives the primary amine (Scheme 2).

Mechanism

Scheme 2

The use of hydrazine to release the primary amine has been subsequently accomplished. This procedure is called Manske modification which finds more useful because it is gentle to other functional groups.

Examples: