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Question
Explain D and L configuration in sugars.
Solution
D and L configuration in sugars:
- Conventionally (+)-glyceraldehyde is represented by the Fischer projection formula having –OH group attached to C-2 on the right side and this configuration is denoted by symbol ‘D’.
- Similarly, the configuration of (–) glyceraldehyde is denoted by the symbol ‘L’.
- All the compounds which can be correlated by a series of chemical reactions to (+)-glyceraldehyde are said to have D-configuration.
- And compounds which are chemically correlated to (–)-glyceraldehyde are said to have L-configuration. This is the system of the relative configuration of chiral compounds.
- A monosaccharide is assigned D/L configuration on the basis of the configuration of the lowest chiral carbon in its Fischer projection formula.
- Relative configuration of (+)-glucose with respect to (+)-glyceraldehyde can be drawn as follows:
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