Textbook Question
What product or products are obtained when D-galactose reacts with each of the following?
e. Br2 in water
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Ch. 20 - The Organic Chemistry of Carbohydrates
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
Chapter 21, Problem 34d
What product or products are obtained when d-galactose reacts with each of the following?
d. excess CH3I + Ag2O
Verified step by step guidance1
Step 1: Understand the structure of d-galactose. D-galactose is an aldohexose, meaning it has six carbon atoms with an aldehyde functional group at the first carbon and hydroxyl groups (-OH) attached to the other carbons.
Step 2: Recognize the role of CH3I (methyl iodide) and Ag2O (silver oxide). CH3I is a methylating agent, and Ag2O acts as a base to facilitate the methylation of hydroxyl groups. In the presence of excess CH3I, all hydroxyl groups on d-galactose will be methylated.
Step 3: Identify the reactive sites on d-galactose. The hydroxyl groups on carbons 2, 3, 4, and 6, as well as the hydroxyl group of the hemiacetal (cyclic form), are susceptible to methylation. The aldehyde group in the linear form does not react under these conditions.
Step 4: Predict the product. When all hydroxyl groups are methylated, the product will be a fully methylated derivative of d-galactose. This includes the conversion of all -OH groups to -OCH3 groups.
Step 5: Consider stereochemistry. The stereochemistry of d-galactose remains intact during methylation, as the reaction does not alter the configuration of the carbon atoms. The final product will be a fully methylated d-galactose derivative with the same stereochemical arrangement as the original molecule.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
D-Galactose Structure and Reactivity
D-galactose is a six-carbon aldose sugar with a specific stereochemistry. Understanding its structure is crucial for predicting its reactivity in organic reactions. The hydroxyl groups on the sugar can participate in nucleophilic substitution reactions, which is essential when considering its reaction with methyl iodide (CH3I).
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Nucleophilic Substitution Reactions
Nucleophilic substitution reactions involve the replacement of a leaving group by a nucleophile. In this case, the hydroxyl group of D-galactose can act as a nucleophile, attacking the electrophilic carbon in methyl iodide (CH3I), leading to the formation of methyl galactoside. Understanding the mechanism of these reactions helps predict the products formed.
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Silver Oxide (Ag2O) as a Reactant
Silver oxide (Ag2O) is often used in organic synthesis as a mild oxidizing agent. In the presence of excess Ag2O, the reaction can facilitate the conversion of the formed methyl galactoside into other products, such as the corresponding aldehyde or carboxylic acid, depending on the reaction conditions. Recognizing the role of Ag2O is key to understanding the overall reaction pathway.
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Related Practice
Textbook Question
What product or products are obtained when D-galactose reacts with each of the following?
f. ethanol + HCl
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Textbook Question
Refer to Figure 20.5 to answer the following questions: b. People with type AB blood can receive blood from anyone, but they cannot give blood to everyone. To whom can they not give blood?
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Textbook Question
What product or products are obtained when D-galactose reacts with each of the following?
b. Ag+, NH3, HO-
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Textbook Question
What product or products are obtained when d-galactose reacts with each of the following?
g.
1. hydroxylamine/trace acid
2. acetic anhydride/∆
3. HO-/H2O
Textbook Question
What product or products are obtained when D-galactose reacts with each of the following?
c. NaBH4, followed by H3O+
1
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