OrgoChem II

Amines

Basicity synthesis and key reactions with carbonyls

Summary

Learn basicity trends and common formation pathways. Full reference is on the external link.

What you need to know:

This topic covers amines. Focus on mastering the key concepts in the "Must know checklist" below. Follow the study steps systematically, and use practice problems to reinforce your understanding. The external reference provides comprehensive coverage of all concepts.

Video Tutorial

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Imine and Enamine Formation Reactions With Reductive Amination

Click to watch on YouTube →

Must know checklist

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Amine classificationprimary (1°: RNH2), secondary (2°: R2NH), tertiary (3°: R3N), quaternary ammonium (R4N+); all have lone pair on N
Imine and Enamine Formation Reactions With Reductive Amination→
Basicity trendsaliphatic amines (pKaH ~9-10) > ammonia (pKaH ~9.2) > aromatic amines (aniline pKaH ~4.6); resonance in aniline delocalizes lone pair, reducing basicity; alkyl groups increase basicity (inductive effect)
Comparing Basic Strength of Nitrogenous Aromatic Molecules→
Reductive aminationcarbonyl (aldehyde/ketone) + amine → imine intermediate → reduction (NaBH4, NaBH3CN, H2/Pd) → amine; versatile for 1°, 2°, 3° amine synthesis
Reductive Amination Mechanism - Imine Formation and Reduction→
Amide formationcarboxylic acid derivative (acid chloride, ester) + amine → amide; amides are weak bases (pKaH ~0-1) due to resonance delocalization of N lone pair into C=O
Amide Formation and Basicity of Amines→
Structure confirmationIR (N-H stretch ~3300-3500, C=O ~1680 for amides); NMR (amine H's ~1-5 ppm, broad if exchangeable); use spectroscopy to verify amine vs amide
Amine Basicity Trends - Resonance and Inductive Effects→

Common mistakes

Ranking aniline as more basic than aliphatic amines (resonance decreases basicity)

Using LiAlH4 to reduce nitro to amine (use Sn/HCl or catalytic H2)

Forgetting reductive amination gives 2° amine from aldehyde + 1° amine