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 - Weak Oxidation (Aldonic Acid)

Organic Chemistry

28. Carbohydrates

Monosaccharides - Weak Oxidation (Aldonic Acid)

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5:08 minutes

Problem 16

Textbook Question

Draw and name the products of bromine water oxidation of
(a) D-mannose
(b) D-galactose
(c) D-fructose

Verified step by step guidance

Understand the reaction: Bromine water is a mild oxidizing agent that selectively oxidizes the aldehyde group (-CHO) of aldoses to a carboxylic acid group (-COOH), forming aldonic acids. Ketoses, like D-fructose, do not directly react with bromine water but can isomerize to aldoses under the reaction conditions.

For (a) D-mannose: Identify the functional groups in D-mannose. It is an aldose with an aldehyde group at C1. Bromine water will oxidize the aldehyde group at C1 to a carboxylic acid group, forming D-mannonic acid. Draw the structure of D-mannonic acid by replacing the -CHO group at C1 with -COOH.

For (b) D-galactose: Similarly, D-galactose is an aldose with an aldehyde group at C1. Bromine water will oxidize the aldehyde group at C1 to a carboxylic acid group, forming D-galactonic acid. Draw the structure of D-galactonic acid by replacing the -CHO group at C1 with -COOH.

For (c) D-fructose: D-fructose is a ketose with a ketone group at C2. Under bromine water conditions, D-fructose can isomerize to D-glucose and D-mannose (both aldoses) via enediol intermediates. These aldoses are then oxidized by bromine water to their respective aldonic acids: D-gluconic acid and D-mannonic acid. Draw the structures of D-gluconic acid and D-mannonic acid.

Name the products: (a) The product of D-mannose oxidation is D-mannonic acid. (b) The product of D-galactose oxidation is D-galactonic acid. (c) The products of D-fructose oxidation are D-gluconic acid and D-mannonic acid.

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Key Concepts

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

Bromine Water as an Oxidizing Agent

Bromine water is a solution of bromine in water, commonly used as an oxidizing agent in organic chemistry. It can oxidize alcohols and sugars, leading to the formation of carbonyl compounds. In the context of carbohydrates, bromine water can oxidize aldoses and ketoses, resulting in the formation of corresponding acids or other oxidized products.

Structure of Carbohydrates

Carbohydrates, such as D-mannose, D-galactose, and D-fructose, are organic compounds made up of carbon, hydrogen, and oxygen. They can exist in various forms, including aldoses (which contain an aldehyde group) and ketoses (which contain a ketone group). Understanding the structural differences between these sugars is crucial for predicting the products of their oxidation reactions.

Oxidation Reactions in Sugars

Oxidation reactions in sugars involve the conversion of hydroxyl groups (-OH) to carbonyl groups (C=O) or the further oxidation to carboxylic acids. For example, D-mannose and D-galactose, being aldoses, can be oxidized to their corresponding aldonic acids, while D-fructose, a ketose, can be oxidized to a ketonic acid. Recognizing these transformations is essential for drawing and naming the products of the reactions.

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