1. Amines Aliphatic and Aromatic

2. General Methods yielding mixture of Amines 1. By reacting alkyl halides with ammonia: Substrate: Alkyl halide Reactant: NH 3 Product: 1°, 2°, 3°, 4° amine in mixture 2. By reacting alcohols with ammonia: Substrate: Alcohol Reactant: NH 3 Product: 1°, 2°, 3°, 4° amine in mixture (If NH 3 is used in large excess then the major product will be 1° amine)

3. Specific Methods yielding 1°Amines 1. By reduction of nitriles: Substrate: Alkyl cyanide Reactant: LiAlH 4 or, Ni & H 2 Product: 1° amine 2. By reduction of oximes : Substrate: Oximes Reactant: LiAlH 4 Product: 1° amine 3. By reduction of nitro compounds : Substrate: Nitroalkanes Reactant: LiAlH 4 or, Ni & H 2 or, Pt Product: 1° amine

4. Specific Methods yielding 1°Amines …..contd. 4. By reduction of amides: Substrate: Amide Reactant: LiAlH 4 Product: 1° amine 5. Hofmann’s degradation of amides : Substrate: Amide Reactant: Br 2 and conc. NaOH Product: 1° amine (decrease in one carbon)

5. Specific Methods yielding 2°Amines 1. By reduction of N-substituted amides: Substrate: Amides Reactant: LiAlH 4 Product: 2° amine Specific Methods yielding 3°Amines 1. By reduction of N,N-disubstituted amides: Substrate: Amides Reactant: LiAlH 4 Product: 3° amine

6. Differentiation between 1°, 2° & 3° amines 1) Hinsberg method 2) Nitrous acid method Isolation of 1°, 2° & 3° amines from mixture 1) Hinsberg method

7. Basicity of amines 2° > 1° > 3° > NH 3 Why amines are basic in nature? Why a different trend is observed in the basicity of 1°, 2° & 3° amines?

8. Aromatic Amines

9. Basicity of aromatic amines Less than Aliphatic ones Why aromatic amines are less basic than aliphatic amines? What is the effect of substituents on basicity of aromatic amines? Explain the basicity of aromatic amines.

10. Basicity of Aromatic Amines Aromatic (and aliphatic) amines owe their basicity to the lone pair of electrons on nitrogen. In determining the relative basicities, always ask yourself about the availability of the nitrogen lone pair electrons for donation to H +. Anything that withdraws electron density from nitrogen decreases basicity, while anything that releases electron density to nitrogen increases basicity. Electron-releasing groups (-CH 3, -OCH 3, -NH 2 ) increase the basicity of aromatic amines Electron-withdrawing groups (-NO 2, -Br, -COOH) decrease the basicity of aromatic amines.

11. Preparation Methods 1. By Ammonolysis of Arylchlorides: Substrate: Chlorobenzene Reactant: NH 3 Catalyst: Cu salts Product: Aniline 2. By reduction of nitro compounds : *most widely used Substrate: Nitrobenzene Reactant: LiAlH 4 or, Ni & H 2 or, Pt or, Sn/Fe with HCl Product: Aniline 3. Hofmann’s degradation of amides : Substrate: Benzamide Reactant: Br 2 in conc. NaOH Product: Aniline (decrease in one carbon)

12. Reactions 1. Reaction with strong acids: Substrate: Aniline Reactant: HCl Product: Phenyl ammonium chloride 2. Reaction with nitrous acids: Substrate: Aromatic amine (1°, 2° or 3°) Reactant: HNO 2 Product: Diazonium salt, nitrosoamine (oil) or, N,N-dialkyl-p-nitroso aniline 3. Oxidation: Substrate: Aniline Reactant: K 2 Cr 2 O 7 /H + or, CF 3 COOH Product: p-benzoquinone or, nitrobenzene Identification

13. Thank You