Amides
Amides
- An amide is made from ammonia (or an amine) and an acyl chloride.
- It can be hydrolysed or reduced.
- It is a much weaker base than an amine.
Practice
An amide is made from an acyl chloride and:
Ammonia or a 1°/2° amine reacts with an acyl chloride to give an amide.
Making and reactions
- Make it: ammonia or a primary amine + an acyl chloride (room temperature).
- hydrolysis (aqueous acid or alkali) → the carboxylic acid (or its salt) + the amine (or ammonium).
- reduction of the C=O with $\text{LiAlH}_4$ → an amine.
Practice
Hydrolysing an amide gives:
Acid or alkali hydrolysis splits the amide into the carboxylic acid and the amine.
Practice
Reducing an amide with LiAlH₄ gives:
LiAlH₄ reduces the amide C=O to give an amine.
Weakly basic
- An amide is a much weaker base than an amine.
- Its nitrogen lone pair is delocalised onto the neighbouring C=O group, so it is not available to accept $\text{H}^+$.
Practice
An amide is a much weaker base than an amine because its nitrogen lone pair is:
Delocalisation onto the adjacent carbonyl makes the lone pair unavailable, so the amide is barely basic.
You've got it
Key idea
- an amide forms from ammonia/amine + acyl chloride
- it hydrolyses to a carboxylic acid (+ amine), and reduces ($\text{LiAlH}_4$) to an amine
- it is a much weaker base than an amine (lone pair delocalised onto the C=O)