Gabriel synthesis gives pure 1° amines without over-alkylation. Steps: (1) Phthalimide + KOH -> potassium phthalimide (N-K salt). (2) K-phthalimide + RX (SN2) -> N-alkylphthalimide. (3) Hydrolysis with NaOH/H2O or hydrazinolysis with N2H4 (Ing-Manske method) -> RNH2 + phthalhydrazide. Limitations: (a) Only 1° amines (2°/3° impossible). (b) R'X must be SN2-reactive (1° or 2° alkyl). (c) Cannot make arylamines (aryl halides don't undergo SN2). (d) Can make benzylamine (C6H5CH2NH2) because benzyl halide is SN2-reactive. This Gabriel-can't-make-aniline-but-can-make-benzylamine distinction is a JEE favourite.