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

Epimerization

Organic Chemistry

28. Carbohydrates

Epimerization

Previous problemNext problem

2:09 minutes

Problem 7

Textbook Question

What sugar is the C-3 epimer of D-fructose?

Verified step by step guidance

Understand the concept of epimers: Epimers are stereoisomers that differ in configuration at only one specific carbon atom, while the rest of the molecule remains identical. In this case, we are looking for the C-3 epimer of D-fructose.

Recall the structure of D-fructose: D-fructose is a ketohexose, meaning it has six carbons and a ketone functional group at the C-2 position. Its Fischer projection shows the hydroxyl (-OH) groups on specific carbons (C-3, C-4, and C-5) in a particular arrangement.

Identify the C-3 position: In the Fischer projection of D-fructose, the C-3 carbon is the third carbon from the top, and its hydroxyl group is on the left side of the projection.

Generate the C-3 epimer: To create the C-3 epimer, invert the configuration of the hydroxyl group at the C-3 position. If the hydroxyl group is on the left in D-fructose, place it on the right for the epimer, while keeping the rest of the molecule unchanged.

Name the resulting sugar: After modifying the C-3 position, determine the name of the new sugar by comparing its structure to known ketohexoses. This will give you the name of the C-3 epimer of D-fructose.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Epimers

Epimers are a specific type of diastereomer that differ in configuration at only one stereogenic center. In the context of sugars, this means that two sugars can have the same molecular formula and differ only at one carbon atom's stereochemistry. Understanding epimers is crucial for identifying relationships between different sugars, such as d-fructose and its epimers.

D-Fructose Structure

D-fructose is a ketohexose sugar, meaning it contains six carbon atoms and a ketone functional group. Its structure includes a carbonyl group at C-2 and hydroxyl groups at the other carbons. Recognizing the structure of d-fructose is essential for determining its epimers, particularly by identifying the stereochemistry at C-3.

Sugar Nomenclature

Sugar nomenclature involves the systematic naming of carbohydrates based on their structure and stereochemistry. The prefixes 'D-' and 'L-' indicate the configuration of the sugar relative to glyceraldehyde, while terms like 'epimer' specify the type of stereochemical difference. Familiarity with this nomenclature is important for accurately identifying and discussing sugars and their relationships.

Watch next

Master General Reaction with a bite sized video explanation from Johnny

Start learning