3.7: Amides- Structures and Names
- Page ID
- 227547
Learning Objectives
- Identify the general structure for an amide.
- Identify the functional group for an amide.
- Names amides with common names.
- Name amides according to the IUPAC system.
The amide functional group has an nitrogen atom attached to a carbonyl carbon atom. If the two remaining bonds on the nitrogen atom are attached to hydrogen atoms, the compound is a simple amide. If one or both of the two remaining bonds on the atom are attached to alkyl or aryl groups, the compound is a substituted amide.
The carbonyl carbon-to-nitrogen bond is called an amide linkage. This bond is quite stable and is found in the repeating units of protein molecules, where it is called a peptide linkage.
Simple, primary amides are named as derivatives of carboxylic acids. The -oic ending of the International Union of Pure and Applied Chemistry (IUPAC) name of the carboxylic acid is replaced with the suffix -amide. In the common nomenclature system, the -ic ending from the common name of the carboxylic acid is replaced with the suffix -amide. The additional nitrogen substituents in secondary and tertiary amides are designated by the prefix N- before the group name, just like in the case of amines:
Example \(\PageIndex{1}\)
Name each compound with the common name, the IUPAC name, or both.
Solution
- This amide has two carbon atoms and is thus derived from acetic acid. The OH of acetic acid is replaced by an NH2 group. The -ic from acetic (or -oic from ethanoic) is dropped, and -amide is added to give acetamide (or ethanamide in the IUPAC system).
- This amide is derived from benzoic acid. The -oic is dropped, and -amide is added to give benzamide.
Exercise \(\PageIndex{1}\)
Name each compound with the common name, the IUPAC name, or both.
Key Takeaways
- Amides have a general structure in which a nitrogen atom is bonded to a carbonyl carbon atom.
- The functional group for an amide is as follows:
- In names for amides, the -ic acid of the common name or the -oic ending of the IUPAC for the corresponding carboxylic acid is replaced by -amide.
Concept Review Exercises
-
Name this compound with the common name and the IUPAC name.
-
Draw a the structural formulae for pentanamide.
Answers
-
β-bromobutyramide (3-bromobutanamide)
-
Exercises
-
Draw the structure for each compound.
- formamide
- hexanamide
-
Draw the structure for each compound.
- propionamide
- butanamide
-
Name each compound with the common name, the IUPAC name, or both.
-
Name the compound.
Answers
-
- propionamide (propanamide)
- α-methylbutyramide (2-methylbutanamide)