Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

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3:17 minutes

Problem 26

Textbook Question

Which of the following amino acid side chains can form an imine with a substrate?

Verified step by step guidance

Understand the concept of imine formation: An imine is formed when a primary amine reacts with a carbonyl group (typically an aldehyde or ketone). The reaction involves the nucleophilic attack of the amine on the carbonyl carbon, followed by dehydration to form the imine.

Identify amino acid side chains that contain a primary amine group: In the context of amino acids, the side chain must have a primary amine group to participate in imine formation. Examples include lysine, which has an ε-amino group in its side chain.

Consider the reactivity of the primary amine: The primary amine in the side chain must be accessible and reactive enough to interact with the substrate's carbonyl group. Lysine's ε-amino group is a good candidate due to its nucleophilicity.

Exclude amino acids without primary amines in their side chains: Amino acids like alanine, valine, and phenylalanine do not have primary amines in their side chains and cannot form imines with a substrate.

Conclude that lysine is the amino acid side chain most likely to form an imine with a substrate due to the presence of its reactive ε-amino group.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Amino Acid Structure

Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid consists of a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group). The nature of the side chain determines the chemical properties and reactivity of the amino acid, including its ability to form imines.

Imine Formation

Imine formation occurs when a carbonyl compound, such as an aldehyde or ketone, reacts with an amine. This reaction involves the nucleophilic attack of the amine on the carbonyl carbon, leading to the release of water and the formation of a double bond between the nitrogen and carbon, resulting in an imine. Understanding this reaction is crucial for identifying which amino acid side chains can participate in imine formation.

Functional Groups in Amino Acids

The side chains of amino acids can contain various functional groups, such as hydroxyl, carboxyl, and amine groups. Amino acids with primary amine groups in their side chains, like lysine, are particularly relevant for imine formation, as they can directly react with carbonyl compounds. Recognizing the functional groups present in the side chains is essential for determining their reactivity and potential to form imines.

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