Concept explainers
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
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.
Based on the Fischer projection formula for the given sugars it is a B-D-glucopyranose monosaccharide.
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.
Based on the Fischer projection formula for the given sugars it is a B-D-glucopyranose monosaccharide.
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Chapter 25 Solutions
Organic Chemistry
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