Question

$\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose are:

• A. Enantiomers
• B. Conformers
• C. Epimers
• D. Anomers

Hint:

α-D-(+)-glucose and β-D-(+)-glucose differ in the configuration at the anomeric carbon, making them anomers.

Answer 1

The Correct Option is D

To understand the relationship between $\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose, we need to consider their structural differences and properties:

Definition of Anomers: Anomers are a type of stereoisomer that differ in configuration specifically at the anomeric carbon. In glucose, the anomeric carbon is the first carbon atom in the sugar ring. The orientation of the hydroxyl group (OH) attached to the anomeric carbon distinguishes anomers

Structure of $\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose: In the cyclic form of glucose, the hydroxyl group on the anomeric carbon can be oriented in two different ways:

• \(\alpha\text{-D-(+)-glucose}\): The hydroxyl group at the anomeric carbon is on the same side as the hydroxyl group on the highest numbered asymmetric carbon (usually on the opposite side of the CH₂OH group in the Haworth projection).
• \(\beta\text{-D-(+)-glucose}\): The hydroxyl group at the anomeric carbon is on the opposite side compared to the hydroxyl group on the highest numbered asymmetric carbon (usually on the same side as the CH₂OH group in the Haworth projection).

Conclusion: The difference in the orientation of the hydroxyl group at the anomeric carbon distinguishes $\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose as anomers. Therefore, the correct answer is Anomers.

By analyzing the structure and definition of anomers, we can understand why $\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose are considered anomers rather than enantiomers, conformers, or epimers.