H но H. но -HO- HO, D-Galactose a-D-Galactose B-D-Galactose b) Draw the most stable chair conformation for B-D-Galactose. c) Draw a structure for the product formed by reaction of D-Galactose with: Tollens' reagent
Carbohydrates
Carbohydrates are the organic compounds that are obtained in foods and living matters in the shape of sugars, cellulose, and starch. The general formula of carbohydrates is Cn(H2O)2. The ratio of H and O present in carbohydrates is identical to water.
Starch
Starch is a polysaccharide carbohydrate that belongs to the category of polysaccharide carbohydrates.
Mutarotation
The rotation of a particular structure of the chiral compound because of the epimerization is called mutarotation. It is the repercussion of the ring chain tautomerism. In terms of glucose, this can be defined as the modification in the equilibrium of the α- and β- glucose anomers upon its dissolution in the solvent water. This process is usually seen in the chemistry of carbohydrates.
L Sugar
A chemical compound that is represented with a molecular formula C6H12O6 is called L-(-) sugar. At the carbon’s 5th position, the hydroxyl group is placed to the compound’s left and therefore the sugar is represented as L(-)-sugar. It is capable of rotating the polarized light’s plane in the direction anticlockwise. L isomers are one of the 2 isomers formed by the configurational stereochemistry of the carbohydrates.
a). The Fischer projection of D-Galactose is given below. Draw Haworthprojections for the a and b anomers (both cyclic hemiacetals) of D-Galactose.
![### Structure and Reactions of D-Galactose
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#### Provided Image Transcription:
![D-Galactose structure diagram]
**D-Galactose:**
Formula: C₆H₁₂O₆
O
|
H-C-OH
|
H-C-H
|
HO-C-H
|
H-C-H
|
HO-C-H
|
H-C-OH
**α-D-Galactose**
**β-D-Galactose**
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**b) Draw the most stable chair conformation for β-D-Galactose.**
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**c) Draw a structure for the product formed by reaction of D-Galactose with:**
**Tollens' reagent**
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#### Detailed Explanations:
**1. Structural Diagram of D-Galactose:**
The structure of D-Galactose consists of six carbon atoms arranged in a chain with various functional groups attached. The groups are as follows:
- Carbon 1 is an aldehyde group (CHO).
- Carbon 2 and 4 have hydroxyl groups (OH) on the left side.
- Carbon 3 and 5 have hydroxyl groups on the right side.
- Carbon 6 is a CH2OH group.
- Remaining hydrogens are single atoms bonded to carbons.
**2. Chair Conformation (for β-D-Galactose):**
The most stable chair conformation of β-D-Galactose needs to minimize steric hindrance by placing bulky groups in equatorial positions. This conformation often needs to be drawn following Robinson projections, considering the hydroxyl groups' axial/equatorial placements.
**3. Reaction with Tollens' Reagent:**
When D-Galactose reacts with Tollens’ reagent (an oxidizing agent), it forms a carboxylic acid from the aldehyde group. In this reaction:
- The aldehyde group (CHO) is oxidized to a carboxyl group (COOH).](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F27b4802f-f0fe-408d-90d1-a8d89e62e50b%2F8304ef1e-ff7b-4f21-a4cb-f398d118a2cf%2Fim5koqm_processed.jpeg&w=3840&q=75)
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