Preparation Methods for Amines — Comparison — Notes | NoteTube

Method	Starting Material	Product	Carbon Change	Key Limitation
Nitro Reduction	$RNO_{2}$ / $ArNO_{2}$ with Sn/HCl or $H_{2}$ /Pd	RN $H_{2}$ / ArN $H_{2}$	No change	Non-selective; reduces all – $NO_{2}$ groups
Gabriel Phthalimide	Phthalimide + KOH, then RX, then $N_{2}H_{4}$	1° Aliphatic amine ONLY	No change	Cannot make ArN $H_{2}$ , 2°, or 3° amines
Hoffmann Bromamide	RCON $H_{2}$ + $Br_{2}$ + 4NaOH	RN $H_{2}$	–1 carbon (vs amide)	Amide must have N-H; not for tertiary amides
Ammonolysis of RX	RX + excess $NH_{3}$ (sealed tube)	Mixture of 1°, 2°, 3°, quaternary salt	No change	Very poor selectivity; mixture hard to separate
Reduction of Nitriles	RCN + $H_{2}$ /Ni or $LiAlH_{4}$	RC $H_{2}$ N $H_{2}$ (1° amine)	+1 carbon (vs nitrile)	Requires nitrile as starting material

Key NEET Trap: Gabriel synthesis CANNOT make aniline (ArN $H_{2}$ ) because ArX does not undergo SN2. Hoffmann degradation gives a product with FEWER carbons — opposite of what most students expect.