Question:medium

Represent α-D-(+)-glucopyranose and β-D-(+)-glucopyranose by Haworth structure.

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Draw the flat pyranose hexagon with ring O at top-right; the anomers differ only at C1 – OH down for α, OH up for β.
Updated On: Jul 10, 2026
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Solution and Explanation

Step 1: Draw the frame. Both anomers share the same flat six-membered Haworth hexagon: five carbons and one oxygen, the oxygen placed between C5 and C1 at the top-right corner, C1 on the right-hand vertex.
Step 2: Place the common substituents. Reading the ring for D-glucose: at C2 the hydroxyl is below the ring, at C3 above, at C4 below, and at C5 the \(\text{-CH}_2\text{OH}\) arm is above the ring (the hallmark of the D-series). The hydrogen on each carbon sits opposite to its OH.
Step 3: Distinguish the anomers at C1. The only structural difference is the orientation of the hemiacetal \(\text{-OH}\) on the anomeric carbon C1. When this \(\text{-OH}\) lies below the plane of the ring the sugar is the \(\alpha\)-anomer; when it lies above the plane it is the \(\beta\)-anomer.
Step 4: Name the two pictures. Thus \(\alpha\)-D-(+)-glucopyranose has C1\(\text{-OH}\) pointing down and \(\beta\)-D-(+)-glucopyranose has C1\(\text{-OH}\) pointing up, everything else being identical. \[ \boxed{\alpha: \text{OH down at C1}, \quad \beta: \text{OH up at C1}} \]
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