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

28. Carbohydrates

Monosaccharides - Alkylation

Organic Chemistry

28. Carbohydrates

Monosaccharides - Alkylation

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4:35 minutes

Problem 25c

Textbook Question

What do the results of parts (a) and (b) imply about the hemiacetal structure of fructose?

Verified step by step guidance

Understand the context: Fructose is a monosaccharide that can exist in both linear and cyclic forms. The cyclic form is created when the hydroxyl group (-OH) on one carbon reacts with the carbonyl group (C=O) on another carbon, forming a hemiacetal or hemiketal structure.

Review the results of parts (a) and (b): Analyze the data or observations provided in parts (a) and (b) to determine whether they support the presence of a hemiacetal structure in fructose. For example, if part (a) involves a reaction with an alcohol and part (b) involves hydrolysis, these could provide evidence of a hemiacetal group.

Recall the properties of hemiacetals: Hemiacetals are typically unstable in aqueous solutions unless they are part of a cyclic structure. If the results of parts (a) and (b) indicate stability or specific reactivity, this could imply that fructose exists predominantly in its cyclic hemiacetal form.

Correlate the experimental results with the structure: If the results of parts (a) and (b) show reactivity consistent with a hemiacetal (e.g., reaction with an acid or base, or formation of a glycosidic bond), this supports the conclusion that fructose adopts a cyclic hemiacetal structure.

Conclude based on the evidence: Summarize how the results of parts (a) and (b) confirm or suggest the presence of a hemiacetal structure in fructose. Highlight the importance of the cyclic form in the behavior and reactivity of fructose.

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Key Concepts

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

Hemiacetal Formation

A hemiacetal is formed when an alcohol reacts with an aldehyde or ketone, resulting in a compound that contains both an alcohol and an ether functional group. In the case of sugars like fructose, this reaction is crucial for the interconversion between the open-chain and cyclic forms of the molecule, which is essential for understanding its structure and reactivity.

Fructose Structure

Fructose is a ketohexose, meaning it has six carbon atoms and a ketone functional group. Its structure can exist in an open-chain form or as a cyclic hemiacetal, where the carbonyl group reacts with a hydroxyl group on the same molecule. This cyclic form is more stable and is the predominant structure in solution, influencing its chemical behavior and interactions.

Anomeric Carbon

The anomeric carbon is the carbon atom in a sugar that was originally part of the carbonyl group and becomes a new chiral center upon cyclization. In fructose, the anomeric carbon plays a critical role in determining the properties of the hemiacetal structure, including its reactivity and the formation of different anomers, which can affect biological interactions and functions.

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