Amides are named according to IUPAC rules, and the system depends on whether they are simple amides (derived from one carboxylic acid and ammonia or amine) or substituted amides (where hydrogens on nitrogen are replaced by alkyl groups).
Here’s a step-by-step guide:
1. Simple Amides (Unsubstituted)
- Start with the name of the parent carboxylic acid.
- Drop the suffix –oic acid (or –ic acid) from the acid name.
- Add the suffix –amide.
Examples:
- Methanoic acid (formic acid) → Methanamide (formamide)
- Ethanoic acid (acetic acid) → Ethanamide (acetamide)
- Benzoic acid → Benzamide
2. Substituted Amides (N-substituted)
- If the nitrogen atom of the amide has alkyl groups attached, they are named as N-substituents.
- Use the prefix N- for each substituent directly attached to the nitrogen.
- List substituents alphabetically.
- Then give the base amide name.
Examples:
- N-methylmethanamide → (CH₃–NH–C(=O)–H)
- N,N-dimethylethanamide → (CH₃–C(=O)–N(CH₃)₂)
3. Cyclic Amides (Lactams)
- Cyclic amides are called lactams.
- They are named by indicating the ring size with a Greek letter (β, γ, δ, etc.) or by numbering.
- Example: 4-aminobutanoic acid cyclizes to γ-lactam.
4. Summary
- Parent acid → replace –oic acid with –amide.
- Nitrogen substituents → prefix with N-.
- Cyclic amides → called lactams.