Chapter 28, Problem 28.45P

Interpretation Introduction

(a)

Interpretation: The Haworth projection for $\text{β-}$ D-talopyranoseby using given structures is to be drawn.

Concept introduction: The structural representation of sugar molecule in cyclic form is known as Haworth projection. Sugar molecule that has six-membered-ring is known as pyranose and sugar molecule that has five-membered-ring is called furanose.

Answer to Problem 28.45P

The Haworth projection for $\text{β-}$ D-talopyranoseby using given structures is,

Explanation of Solution

The structure of D-talose is,

Figure 1

The steps for the conversion of Fischer projection of D-talose into Haworth projection is as follow:

Step-1 Talopyranose ring is formed by the attack of $\text{OH}$ substituent at $\text{C5}$ on the carbonyl carbon.

Step 2 The Haworth projection of D-talopyranose, ${\text{CH}}_{\text{2}}\text{OH}$ is drawn above the ring.

Step 3 In the beta-form, the substituents ${\text{CH}}_{\text{2}}\text{OH}$ and $\text{OH}$ at $\text{C1}$ are cis to each other. Thus, both are drawn above the ring.

Step-4 The substituents which are present on the right side in the Fischer projection are drawn on the below the ring in the Haworth projection. Similarly, the substituents which are present on the left side in the Fischer projection are drawn on the above the ring in the Haworth projection.

The conversion of D-talose into $\text{β-}$ D-talopyranose is shown below.

Figure 2

Conclusion

The Haworth projection for $\text{β-}$ D-talopyranoseby using given structures is shown in Figure 2.

Interpretation Introduction

(b)

Interpretation: The Haworth projection for $\text{β-}$ D-mannopyranoseby using given structure is to be drawn.

Concept introduction: The structural representation of sugar molecule in cyclic form is known as Haworth projection. Sugar molecule that has six-membered-ring is known as pyranose and sugar molecule that has five-membered-ring is called furanose.

Answer to Problem 28.45P

The Haworth projection for $\text{β-}$ D-mannopyranose by using given structure is,

Explanation of Solution

The structure of D-mannose is,

Figure 3

The steps for the conversion of Fischer projection of D-mannose into Haworth projection is as follow:

Step-1 Mannosepyranose ring is formed by the attack of $\text{OH}$ substituent at $\text{C5}$ on the carbonyl carbon.

Step 2 The Haworth projection of D-mannosepyranose, ${\text{CH}}_{\text{2}}\text{OH}$ is drawn above the ring.

Step 3 In the beta-form, the substituents ${\text{CH}}_{\text{2}}\text{OH}$ and $\text{OH}$ at $\text{C1}$ are cis to each other. Thus, both are drawn above the ring.

Step-4 The substituents which are present on the right side in the Fischer projection are drawn on the below the ring in the Haworth projection. Similarly, the substituents which are present on the left side in the Fischer projection are drawn on the above the ring in the Haworth projection.

The conversion of D-mannose into D-mannosepyranose is shown below.

Figure 4

Conclusion

The Haworth projection for $\text{β-}$ D-mannosepyranose by using given structure is shown in Figure 4.

Interpretation Introduction

(c)

Interpretation: The Haworth projection for $\text{α-}$ D-galactopyranose by using given structure is to be drawn.

Concept introduction: The structural representation of sugar molecule in cyclic form is known as Haworth projection. Sugar molecule that has six-membered-ring is known as pyranose and sugar molecule that has five-membered-ring is called furanose.

Answer to Problem 28.45P

The Haworth projection for $\text{α-}$ D-galactopyranose by using given structure is,

Explanation of Solution

The structure of D-galactose is,

Figure 5

The steps for the conversion of Fischer projection of D-galactose into Haworth projection is as follow:

Step-1 Galactopyranose ring is formed by the attack of $\text{OH}$ substituent at $\text{C5}$ on the carbonyl carbon.

Step 2 The Haworth projection of D-galactopyranose, ${\text{CH}}_{\text{2}}\text{OH}$ is drawn above the ring.

Step 3 In the alpha-form, the substituents ${\text{CH}}_{\text{2}}\text{OH}$ and $\text{OH}$ at $\text{C1}$ are trans to each other. Thus, both are drawn above the ring.

Step-4 The substituents which are present on the right side in the Fischer projection are drawn on the below the ring in the Haworth projection. Similarly, the substituents which are present on the left side in the Fischer projection are drawn on the above the ring in the Haworth projection.

The conversion of D-galactose into D-galactopyranose is shown below.

Figure 6

Conclusion

The Haworth projection for $\text{β-}$ D-galactopyranose by using given structure is shown in Figure 6.

Interpretation Introduction

(d)

Interpretation: The Haworth projection for $\text{α-}$ D-ribofuranose by using given structure is to be drawn.

Concept introduction: The structural representation of sugar molecule in cyclic form is known as Haworth projection. Sugar molecule that has six-membered-ring is known as pyranose and sugar molecule that has five-membered-ring is called furanose.

Answer to Problem 28.45P

The Haworth projection for $\text{α-}$ D-ribofuranose by using given structure is,

Explanation of Solution

The structure of D-ribose is,

Figure 7

The steps for the conversion of Fischer projection of D-ribose into Haworth projection is as follow:

Step-1 Ribofuranose ring is formed by the attack of $\text{OH}$ substituent at $\text{C4}$ on the carbonyl carbon.

Step 2 The Haworth projection of D-ribofuranose, ${\text{CH}}_{\text{2}}\text{OH}$ is drawn above the ring.

Step 3 In the alpha-form, the substituents ${\text{CH}}_{\text{2}}\text{OH}$ and $\text{OH}$ at $\text{C1}$ are trans to each other. Thus, both are drawn above the ring.

Step-4 The substituents which are present on the right side in the Fischer projection are drawn on the below the ring in the Haworth projection. Similarly, the substituents which are present on the left side in the Fischer projection are drawn on the above the ring in the Haworth projection.

The conversion of D-ribose into D-ribofuranose is shown below.

Figure 8

Conclusion

The Haworth projection for $\text{α-}$ D-ribofuranose by using given structure is shown in Figure 8.

Interpretation Introduction

(e)

Interpretation: The Haworth projection for $\text{α-}$ D-tagatofuranose by using given structure is to be drawn.

Concept introduction: The structural representation of sugar molecule in cyclic form is known as Haworth projection. Sugar molecule that has six-membered-ring is known as pyranose and sugar molecule that has five-membered-ring is called furanose.

Answer to Problem 28.45P

The Haworth projection for $\text{α-}$ D-tagatofuranose by using given structure is,

Explanation of Solution

The structure of D-tagatose is,

Figure 9

The steps for the conversion of Fischer projection of D-tagatose into Haworth projection is as follow:

Step-1 Tagatofuranose ring is formed by the attack of $\text{OH}$ substituent at $\text{C5}$ on the carbonyl carbon.

Step 2 The Haworth projection of D-tagatofuranose, ${\text{CH}}_{\text{2}}\text{OH}$ is drawn above the ring.

Step 3 In the alpha-form, the substituents ${\text{CH}}_{\text{2}}\text{OH}$ and $\text{OH}$ at $\text{C1}$ are trans to each other. Thus, both are drawn above the ring.

Step-4 The substituents which are present on the right side in the Fischer projection are drawn on the below the ring in the Haworth projection. Similarly, the substituents which are present on the left side in the Fischer projection are drawn on the above the ring in the Haworth projection.

The conversion of D-tagatose into D-tagatofuranose is shown below.

Figure 10

Conclusion

The Haworth projection for $\text{α-}$ D-tagatofuranose by using given structure is shown in Figure 10.