Concept explainers
Interpretation:
From the cyclic structure of allose given, whether it is i) a furanose or pyranose form ii) α- or β- anomer iii) D or L sugar are to be stated.
Concept introduction:
The pyranose form is a cyclic hemiacetal form with a six membered ring formed by the nucleophilic addition of the –OH group on C5 to the C1 carbonyl group. The furanose form is a cyclic hemiacetal form with a five membered ring formed by the nucleophilic addition of the –OH group on C5 to the C2 carbonyl group.
The orientation of –OH group differs in α- and β- anomers. In α- anomer the OH on C1 is cis to the –OH at the lowest chirality center in Fischer projection, while in β- anomer the –OH on C1 is trans to the –OH at the lowest chirality center in Fischer projection.
D sugars have the –O- at C5 on the right in the uncoiled form while L sugars have -O- at C5 on the left.
To state:
From the cyclic structure of allose given, whether it is i) a furanose or pyranose form ii) α- or β- anomer iii) D or L sugar.
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Chapter 25 Solutions
Organic Chemistry
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