Lecture Notes: Amides

Introduction

• Amides Overview
  • Discussed amides' general structure.
  • Formation using acyl chlorides.
  • Why amides are weaker bases than amines.
  • Hydrolysis of amides.
• Contextual Background
  • Reference to separate videos for amines and nucleophilic mechanisms.

Amines Background

• Amines and Their Derivation
  • Organic compounds derived from ammonia (NH3).
  • Can be aliphatic (alkyl group) or aromatic (aryl group).
• Types of Amines
  • Primary Amines: One carbon group bonded to nitrogen.
  • Secondary Amines: Two carbon groups bonded to nitrogen.
  • Tertiary Amines: Three carbon groups bonded to nitrogen.

Acyl Chlorides

• Structure:
  • Derivatives of carboxylic acids.
  • Functional group: carbon atom double-bonded to oxygen and single-bonded to chlorine.
  • Highly reactive.

Amides Structure

• General Structure
  • Carboxylic acid derivatives.
  • Contains carbon atom double-bonded to oxygen and single-bonded to nitrogen.
• Types of Amides
  • Primary Amides: Nitrogen with NH2 group, no carbon groups.
  • Secondary Amides: One additional carbon group bonded to nitrogen.
  • Tertiary Amides: Two additional carbon groups bonded to nitrogen.

Amide Formation

• Primary Amides
  • Formed from acyl chloride reaction with ammonia.
  • Reaction: Addition-elimination, producing primary amide and ammonium chloride.
  • Example: Ethanol chloride with ammonia forms ethanamide.
• Secondary Amides
  • Formed from acyl chloride reaction with a primary amine.
  • Example: Ethanol chloride with ethyl amine forms N-ethyl ethanamide.

Basicity of Amides

• Comparison with Amines
  • Amides are weaker bases than amines.
  • Carbon-oxygen double bond in amides reduces nitrogen's electron density.
  • Oxygen's high electronegativity affects electron distribution.
• Positive Inductive Effect
  • Amines have increased electron density around nitrogen due to alkyl groups.
  • Stronger base than amides due to availability of lone electron pair.

Hydrolysis of Amides

• Hydrolysis Types
  • Acid Hydrolysis:
    • Heated with dilute acid to form carboxylic acid and ammonium salt.
  • Alkali Hydrolysis:
    • Heated with sodium hydroxide to form carboxylate ion and ammonia.
• Example
  • Ethanoate and ammonia from ethanamide with sodium hydroxide.
  • Ethanoic acid from ethanamide with hydrochloric acid.

Summary

• Key Points
  • Amides contain carbon double-bonded to oxygen, single-bonded to nitrogen.
  • Formation via acyl chloride and ammonia/amine reactions.
  • Weaker bases than amines due to electron density effects.
  • Hydrolysis breaks amides into acids and amines/ammonia.

• Check additional resources and videos for detailed mechanisms and further explanations.