D-Mannose differs from D-glucose in its stereochemistry at `C-2`. The pyranose form of D-Mannose is.

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Answer

To determine the structure of the pyranose form of D-Mannose, we need to analyze its stereochemistry, particularly at C-2, and compare it with D-Glucose. Here’s a step-by-step solution:

### Step 1: Understand the Structure of D-Glucose
- D-Glucose can exist in two anomeric forms: alpha (α) and beta (β).
- In the pyranose form, D-Glucose has a six-membered ring structure with five carbon atoms and one oxygen atom.

### Step 2: Draw the Pyranose Form of D-Glucose
- For α-D-Glucose, the hydroxyl group (OH) on the anomeric carbon (C-1) is positioned below the plane of the ring.
- For β-D-Glucose, the hydroxyl group on C-1 is above the plane of the ring.

### Step 3: Identify the Difference at C-2
- D-Mannose differs from D-Glucose at C-2. In D-Glucose, the configuration at C-2 is (OH on the right), while in D-Mannose, it is (OH on the left).

### Step 4: Draw the Pyranose Form of D-Mannose
- For α-D-Mannose, the structure will be similar to α-D-Glucose, but with the OH group on C-2 positioned to the left.
- For β-D-Mannose, the structure will have the OH group on C-1 above the plane and the OH group on C-2 to the left.

### Step 5: Final Structures
- The final structures for α-D-Mannose and β-D-Mannose can be summarized as follows:
- **α-D-Mannose**: OH on C-1 is below the plane, and OH on C-2 is to the left.
- **β-D-Mannose**: OH on C-1 is above the plane, and OH on C-2 is to the left.

### Conclusion
The pyranose form of D-Mannose can be represented in both α and β forms, with the key difference in stereochemistry at C-2 compared to D-Glucose.

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