Preparation of Amines

Four distinct synthetic methods are used to build up an amine, most often a primary

amine, and each has its own scope and limitation -- so choosing the RIGHT method for a

given target amine is as important as knowing the reaction itself:

1. Reduction of a nitro compound, a nitrile, or an amide (Section 25.5.1) -- three independent routes converging on the same functional group.
2. Ammonolysis of a haloalkane with excess ammonia (Section 25.5.2) -- simple in concept but prone to over-alkylation.
3. The Gabriel phthalimide synthesis (Section 25.5.3) -- the most reliable method for an aliphatic primary amine completely free of secondary/tertiary contamination.
4. The Hoffmann bromamide degradation (Section 25.5.4) -- unique among these methods because it SHORTENS the carbon chain by one carbon relative to the starting material.

Across all four, the recurring theme is that a primary amine can be reached from several

different starting functional groups, and the choice between them in practice is …