Chapter 25.SE, Problem 26VC

Interpretation Introduction

a)

Interpretation:

The configurational stereochemistry of the molecules to be determined.

Answer to Problem 26VC

The Fischer projection follows as

It is D sugar the molecule is a retrose. Elclose or eldotetrose, is 4-carbon elclose.

Explanation of Solution

Concept strategy: The Fischer projection of the given monosaccharide is drawn vertically, by rotating the molecule anticlockwise 90° so that the carbonyl aldehyde -CHO group is vertically at the top and the CH₂OH group is at the bottom. [The red balls represent oxygen atoms, the black balls represent carbon atoms, and each smell white ball represents hydrogen]. The intention –H and –OH are drawn to the sides, pointing art of the page towards the review. Thus the given model becomes

Review from front side C-3-OH is to the right By convention the molecule has the C-3 hyduxyl at the right. So it is D sugar the molecule is a retrose. Elclose or eldotetrose, is 4-carbon elclose.

Conclusion

Based on the Fischer projection formula for the given sugars it is a B-D-glucopyranose monosaccharide.

Interpretation Introduction

b)

Interpretation:

The configurational stereochemistry of the molecules to be determined.

Answer to Problem 26VC

The given model is the cyclic structures of an aldohexose in six membered pyranose form.

Strategy: We redraw the model as

Explanation of Solution

By convention, the terminal -CH₂OH group is on the top of the chair Pyranose structure. Thus it is a D sugar. The molecule is an aldohexose is B-D-glucopyranose, all the –OH groups are equatorial (and more stable due to minimum repulsion) conformation.

Conclusion

Based on the Fischer projection formula for the given sugars it is a B-D-glucopyranose monosaccharide.