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🥼organic chemistry review

Amide Group

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The amide group is a functional group in organic chemistry consisting of a carbonyl (C=O) group connected to a nitrogen atom. It is a key structural feature in many important biomolecules, such as proteins and peptides, and is also found in various synthetic compounds.

5 Must Know Facts For Your Next Test

  1. The amide group can participate in resonance, leading to a partial double-bond character between the carbonyl carbon and the nitrogen atom.
  2. Amide groups can form hydrogen bonds, which contribute to the stability and secondary structure of proteins.
  3. The presence of an amide group can affect the reactivity and physical properties of a molecule, such as its polarity, solubility, and melting point.
  4. Amide groups are commonly found in many natural and synthetic compounds, including peptides, proteins, and various pharmaceuticals.
  5. The formation of amide bonds is a key step in the synthesis of many organic compounds and is often facilitated by coupling reagents or enzymes.

Review Questions

  • Explain the concept of resonance as it applies to the amide group, and how it affects the structure and properties of the group.
    • The amide group can exhibit resonance, where the carbonyl carbon and the nitrogen atom share a partial double-bond character. This resonance stabilizes the amide group and results in a planar structure, with the carbonyl oxygen, the carbonyl carbon, the nitrogen atom, and the attached hydrogen or substituent all lying in the same plane. The resonance also contributes to the partial double-bond character of the C-N bond, which can affect the reactivity and physical properties of the amide group, such as its polarity and resistance to hydrolysis.
  • Describe the role of hydrogen bonding in the stabilization of the secondary structure of proteins, and how the amide group is involved in this process.
    • The amide group in proteins plays a crucial role in the stabilization of the secondary structure, such as alpha-helices and beta-sheets, through the formation of hydrogen bonds. The carbonyl oxygen of the amide group can act as a hydrogen bond acceptor, while the hydrogen atom attached to the nitrogen can act as a hydrogen bond donor. These hydrogen bonds between the amide groups of adjacent amino acid residues help maintain the overall secondary structure of proteins, contributing to their stability and biological function.
  • Analyze the importance of amide groups in the synthesis of organic compounds, particularly in the context of peptide and protein synthesis, and discuss the role of coupling reagents or enzymes in facilitating these reactions.
    • The formation of amide bonds is a crucial step in the synthesis of many organic compounds, especially in the context of peptide and protein synthesis. Amide bonds connect the carbonyl carbon of one amino acid to the amino nitrogen of another, creating the peptide backbone that forms the primary structure of proteins. This reaction is often facilitated by coupling reagents or enzymes, which help activate the carboxylic acid group and promote the nucleophilic attack of the amino group, leading to the formation of the amide bond. The ability to selectively form amide bonds is essential for the synthesis of complex biomolecules, as well as many pharmaceuticals and other important organic compounds.