The ‘D’ in D(+)-glucose represents its configuration, specifically indicating its relation to the D isomer of glyceraldehyde. It is not directly related to the optical activity of the compound, which is denoted by the ‘(+)’ symbol representing its dextrorotatory nature.
What does the ‘D’ in D(+)-glucose signify, and how is it related to the optical activity of the molecule?
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The ‘D’ in D(+)-glucose signifies the configuration of the molecule concerning its chiral center farthest from the carbonyl group. In glucose, this chiral center is the asymmetric carbon at the fifth position. The term ‘D’ indicates that the hydroxyl group on this chiral center is on the right side in a Fischer projection. D-glucose exhibits dextrorotatory optical activity, meaning it rotates plane-polarized light to the right. Its mirror image, L-glucose, with the hydroxyl group on the left, would be levorotatory. The ‘D’ and ‘L’ nomenclature helps convey the three-dimensional arrangement of atoms in a molecule, especially relevant for sugars with multiple chiral centers.