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

29. Amino Acids

Proteins and Amino Acids

Organic Chemistry

29. Amino Acids

Proteins and Amino Acids

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5:53 minutes

Problem 24b

Textbook Question

What amino acid is formed when the aldehyde used in the Strecker synthesis is
b. 2-methylbutanal?

Verified step by step guidance

The Strecker synthesis is a method for synthesizing α-amino acids by reacting an aldehyde with ammonium chloride (NH₄Cl) and potassium cyanide (KCN). The process involves the formation of an imine intermediate, followed by cyanide addition and hydrolysis.

Identify the aldehyde provided in the problem: 2-methylbutanal. Its structure consists of a four-carbon chain with a methyl group attached to the second carbon and an aldehyde functional group (-CHO) at the terminal carbon.

In the first step of the Strecker synthesis, the aldehyde (2-methylbutanal) reacts with ammonium chloride (NH₄Cl) and forms an imine intermediate through a condensation reaction. This imine has the general structure R-CH=NH, where R represents the 2-methylbutyl group.

Next, potassium cyanide (KCN) reacts with the imine intermediate. The cyanide ion (CN⁻) adds to the carbon atom of the imine, forming an α-aminonitrile intermediate. The structure of this intermediate will have the 2-methylbutyl group, an amino group (-NH₂), and a nitrile group (-C≡N) attached to the same carbon.

Finally, the α-aminonitrile undergoes hydrolysis under acidic conditions. The nitrile group (-C≡N) is converted into a carboxylic acid group (-COOH), resulting in the formation of the α-amino acid. The amino acid formed will have the 2-methylbutyl group as its side chain, making it isoleucine.

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Key Concepts

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

Strecker Synthesis

Strecker synthesis is a method for producing amino acids from aldehydes or ketones. It involves the reaction of an aldehyde with ammonia and hydrogen cyanide, leading to the formation of an α-amino nitrile intermediate, which can be hydrolyzed to yield the corresponding amino acid. Understanding this process is crucial for determining the specific amino acid produced from a given aldehyde.

Amino Acid Structure

Amino acids are organic compounds characterized by the presence of both an amino group (-NH2) and a carboxyl group (-COOH), along with a unique side chain (R group) that determines the properties of the amino acid. The structure of the amino acid formed in the Strecker synthesis will depend on the aldehyde used, in this case, 2-methylbutanal, which influences the resulting side chain and overall identity of the amino acid.

Aldehyde Reactivity

Aldehydes are reactive carbonyl compounds that can undergo various chemical reactions, including nucleophilic addition. In the context of Strecker synthesis, the aldehyde reacts with ammonia and cyanide to form an amino nitrile. The specific structure of the aldehyde, such as 2-methylbutanal, affects the final amino acid product, making it essential to understand how different aldehydes influence reactivity and product formation.