Chapter 24, Problem 24.40AP

Interpretation Introduction

(a)

Interpretation:

Whether hexose corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. They have the general molecular formula, ${\left({\text{CH}}_{\text{2}}\text{O}\right)}_{\text{n}}$.

The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The sugar hexose is not the correct description of $\text{L-sorbose}$.

Explanation of Solution

Monosaccharide with the six-carbon atom is known as hexose.

The presence of a keto group in $\text{L-sorbose}$ causes the difference in their structures.

However, the keto group is missing in hexose as shown below.

Figure 1

Conclusion

The term hexose is not the correct description of the $\text{L-sorbose}$ as shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

Whether ketohexose corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The sugar ketohexose is the correct description of $\text{L-sorbose}$.

Explanation of Solution

The class of the sugars which is fundamental in carbohydrates with presence of keto group is known as ketohexose sugars.

The presence of keto group in ketohexose shows similarity with $\text{L-sorbose}$ as shown below.

Figure 2

Conclusion

The ketohexose is the correct description of the $\text{L-sorbose}$ structure. The consideration of chemical formula with a keto group is similar in ketohexose as well as $\text{L-sorbose}$.

Interpretation Introduction

(c)

Interpretation:

Whether glycoside molecule corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The carbohydrate $\text{L-sorbose}$ can not be described by the help of structure of glycoside sugars.

Explanation of Solution

Two molecules of sugar which are connected to a glycosidic bond is known as glycoside molecule. The glycosidic bond is used to join two carbohydrate molecules.

The cyclic acetal group is not present in the $\text{L-sorbose}$. Therefore, the glycoside molecule is not the correct description of the carbohydrate $\text{L-sorbose}$.

Conclusion

The glycoside molecule is not the correct description of the $\text{L-sorbose}$ structure.

Interpretation Introduction

(d)

Interpretation:

Whether aldohexose corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The carbohydrate $\text{L-sorbose}$ can not be described by the help of structure of aldohexose sugars.

Explanation of Solution

The aldohexose belongs to the category of hexose in which aldehyde group is present at first carbon. In the $\text{L-sorbose}$, keto group is present. The differences in their group and their arrangements causes the description between $\text{L-sorbose}$ and aldohexose.

Conclusion

The sugar $\text{L-sorbose}$ can not be described by the help of structure of aldohexose sugars due to the presence of an aldehydic group in aldohexose sugars.

Interpretation Introduction

(e)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is the correct description of $\text{L-sorbose}$.

Explanation of Solution

The stereocenters are defined as the centers which are chiral in nature or attached with four different substituents. The stereocenters which are in direction of anticlockwise or left-hand nomenclaturehave $R$ configuration. The stereocenters which are in direction of clockwise or right-hand nomenclature have $S$ configuration.

The configuration of $\text{L-sorbose}$ at $\text{C-5}$ position is $S$ configuration which is similar to the given structure as shown below.

Figure 3

Therefore, the given structure is the correct description of $\text{L-sorbose}$.

Conclusion

The given structure shown in Figure 3 is the correct description of $\text{L-sorbose}$.

Interpretation Introduction

(f)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is not similar to the $\text{L-sorbose}$.

Explanation of Solution

The stereocenters are defined as the centers which are chiral in nature or attached with four different substituents. The stereocenters which are in the direction of anticlockwise or left-hand nomenclature, the configuration of that stereocenter is $R$. The stereocenters which are in direction of clockwise or right-hand nomenclature, the configuration of that stereocenter is $S$.

The configuration of $\text{L-sorbose}$ at $\text{C-5}$ position is $S$ which is not similar to the given structure. The configuration of the given structure is $R$ as shown below.

Figure 4

Conclusion

The given structure shown in Figure 4 is not the correct description of $\text{L-sorbose}$.

Interpretation Introduction

(g)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is not similar to the $\text{L-sorbose}$.

Explanation of Solution

The Haworth projection is used for the arrangements of cyclic sugars. The $D$ and $L$ configuration of sugars are converted into $\text{α}$ and $\text{β}$ form in Haworth projection. The groups which are present on the left side in Fisher project upwards in the Haworth projection. The groups which are present on the right side in Fisher project downwards in the Haworth projection. The hydroxymethyl group is projected downwards then the configuration is known as $L\text{-}$ configuration. The hydroxymethyl group is projected upwardsthen the configuration is known as $\text{D-}$ configuration. The given structure is in $\text{D-}$ configuration as at ${\text{C}}_{\text{6}}$ position of the hydroxymethyl group is projected upwards as shown below.

Figure 5

Conclusion

The given structure is not a proper description for $\text{L-sorbose}$ due to the difference in their configurations as shown in Figure 5.

Interpretation Introduction

(h)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is not similar to the $\text{L-sorbose}$.

Explanation of Solution

The Haworth projection is used for the arrangements of cyclic sugars. The $D$ and $L$ configuration of sugars are converted into $\text{α}$ and $\text{β}$ form in Haworth projection. The groups which are present on the left side in Fisher are project upwards in the Haworth projection. The groups which are present on the right side in Fisher are projected downwards in the Haworth projection. The hydroxymethyl group is projected downwards then the configuration is known as $L\text{-}$ configuration. The hydroxymethyl group is projected upwards then the configuration is known as $D\text{-}$ configuration. The given structure is in $D\text{-}$ configuration as its ${\text{C}}_{\text{6}}$ position of the hydroxymethyl group is projected upwards as shown below.

Figure 6

Conclusion

The configuration of sorbose is in $L\text{-}$ configuration. The configuration of the given structure is in $D\text{-}$ configuration. Therefore, the given structure is not a proper description for $\text{L-sorbose}$ due to the difference in their configurations as shown in Figure 6.

Interpretation Introduction

(i)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is similar to the $\text{L-sorbose}$.

Explanation of Solution

The Haworth projection is used for the arrangements of cyclic sugars. The $D$ and $L$ configuration of sugars are converted into $\text{α}$ and $\text{β}$ form in Haworth projection. The groups which are present on the left side in Fisher are project upwards in the Haworth projection. The groups which are present on the right side in Fisher areprojected downwards in the Haworth projection. The hydroxymethyl group is projected downwards then the configuration is known as $L\text{-}$-configuration. The hydroxymethyl group is projected upwards then the configuration is known as $D\text{-}$-configuration. The given structure is in L-configuration as its ${\text{C}}_{\text{6}}$ position of the hydroxymethyl group is projected downwards as shown below.

Figure 7

Conclusion

The given structure is the correct description for $\text{L-sorbose}$ as shown in Figure 7.

Interpretation Introduction

(j)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

The pyranoses can be classified as $\text{α}$ or $\text{β}$ based upon the configuration at the anomeric carbon. The anomeric carbon is the one which is a part of the carbonyl group in the straight-chain structure of the carbohydrate.

Answer to Problem 24.40AP

The given structure is not the correct description of $\text{L-sorbose}$.

Explanation of Solution

The most stable conformation of cyclohexane is chair form due to the axial and equatorial position. The angle between the carbon-carbon bond is near about $\text{109}\text{.5}°$ which is free from angle strain. The atoms present on the left-hand side of the Fisher projection are placed upwards in the chair conformation. The atoms present on the right-hand side of the Fisher projection are placed downwards in the chair conformation.

The given structure is not the correct description of $\text{L-sorbose}$ due to the presence of hydroxymethyl group as the substituent in the given structure. The given structure is shown below.

Figure 8

Conclusion

The given structure is not the correct description of $\text{L-sorbose}$ is shown in Figure 8.

Interpretation Introduction

(k)

Interpretation:

Whether given structure corresponds to the correct description of the $\text{L-sorbose}$ structure or a form with which it is in equilibrium is to be predicted.

Concept introduction:

Carbohydrates are a class of organic compounds. They can be present in the form of open chains or rings. They are usually an aldehyde or ketone with additional hydroxyl groups. The six-membered ring form of carbohydrates is termed as pyranose. The five-membered ring form of carbohydrates is termed as furanose.

Answer to Problem 24.40AP

The given structure is the correct description of $\text{L-sorbose}$ because the arrangement of all the groups are similar to the $\text{L-sorbose}$ sugar.

Explanation of Solution

The most stable conformation of cyclohexane is chair form due to the axial and equatorial position. The angle between the carbon-carbon bond is near about $\text{109}\text{.5}°$ which is free from angle strain. The atoms present on the left-hand side of the Fisher projection is placed upwards in the chair conformation. The atoms present on the right-hand side of the Fisher projection is placed downwards in the chair conformation.

All the substituents or groups are present in the same manner with respect to the $\text{L-sorbose}$ as shown below.

Figure 9

Conclusion

The given structure is the correct description of $\text{L-sorbose}$ as shown in Figure 9.