upgrade

🥼organic chemistry review

Oxime

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

Definition

An oxime is a functional group consisting of a hydroxylamine (R1R2C=NOH) formed by the condensation reaction between a carbonyl compound (aldehyde or ketone) and hydroxylamine. Oximes are important intermediates in organic synthesis and have various applications.

5 Must Know Facts For Your Next Test

  1. Oximes are formed by the condensation reaction between a carbonyl compound (aldehyde or ketone) and hydroxylamine (NH2OH).
  2. Oximes are useful in organic synthesis as they can be converted to other functional groups, such as nitriles, nitro compounds, and amines.
  3. Oximes are important intermediates in the synthesis of various pharmaceuticals and other biologically active compounds.
  4. The formation of oximes is a reversible reaction, and the equilibrium can be shifted by adjusting the reaction conditions, such as pH and temperature.
  5. Oximes can be used as protecting groups for carbonyl compounds in organic synthesis, as they are relatively stable and can be easily removed.

Review Questions

  • Explain the mechanism of the nucleophilic addition reaction between a carbonyl compound and hydroxylamine to form an oxime.
    • The mechanism of the nucleophilic addition reaction between a carbonyl compound and hydroxylamine to form an oxime involves several steps. First, the carbonyl carbon is electrophilically attacked by the nucleophilic nitrogen of hydroxylamine, forming a tetrahedral intermediate. This intermediate then undergoes dehydration, resulting in the formation of the C=N double bond of the oxime. The reaction is reversible, and the equilibrium can be shifted by adjusting the reaction conditions, such as pH and temperature.
  • Discuss the importance of oximes in organic synthesis and their applications in the synthesis of various compounds.
    • Oximes are important intermediates in organic synthesis due to their versatility. They can be converted to other functional groups, such as nitriles, nitro compounds, and amines, which are valuable building blocks for the synthesis of various pharmaceuticals and other biologically active compounds. Oximes are also used as protecting groups for carbonyl compounds in organic synthesis, as they are relatively stable and can be easily removed. The ability to manipulate oximes and their derivatives makes them a crucial tool in the arsenal of organic chemists.
  • Analyze the relationship between the formation of oximes and the nucleophilic addition of amines to form imines and enamines, and explain how these reactions are connected within the context of 19.8 Nucleophilic Addition of Amines: Imine and Enamine Formation.
    • The formation of oximes is closely related to the nucleophilic addition of amines to form imines and enamines, as they all involve the condensation of a carbonyl compound with a nucleophilic species. In the case of oxime formation, the nucleophile is hydroxylamine (NH2OH), while in the formation of imines and enamines, the nucleophiles are primary and secondary amines, respectively. All of these reactions are examples of nucleophilic addition reactions, where the nucleophile adds to the electrophilic carbonyl carbon, resulting in the formation of a new carbon-heteroatom bond. Understanding the similarities and differences between these reactions is crucial in the context of 19.8 Nucleophilic Addition of Amines: Imine and Enamine Formation, as it allows for a deeper comprehension of the underlying principles governing these important organic transformations.