Disaccharides are of four types, namely 1,4'-glycosides, 1-6'-glycosides, 1,1'-glycosides are 1,5'-glycosides. Which of these will be reducing

Options

A. 1.4'-
B. 1,6'-
C. 1,1'-
D. 1,5'-

Explanation

To determine which of the disaccharides are reducing sugars among the types mentioned (1,4'-glycosides, 1,6'-glycosides, 1,1'-glycosides, and 1,5'-glycosides), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Reducing Sugars**:
- Reducing sugars are carbohydrates that can donate electrons to another chemical species, typically because they have a free aldehyde or ketone group. This means they can be oxidized.

2. **Identifying the Types of Glycosidic Bonds**:
- The disaccharides mentioned are linked by different glycosidic bonds:
- 1,4'-glycosides: Glycosidic bond between the first carbon of one sugar and the fourth carbon of another.
- 1,6'-glycosides: Glycosidic bond between the first carbon of one sugar and the sixth carbon of another.
- 1,1'-glycosides: Glycosidic bond between the first carbon of one sugar and the first carbon of another.
- 1,5'-glycosides: Glycosidic bond between the first carbon of one sugar and the fifth carbon of another.

3. **Analyzing Each Type**:
- **1,4'-glycosides**: This type retains a free anomeric carbon (the carbon that was part of the aldehyde or ketone group in the monosaccharide). Therefore, it can act as a reducing sugar.
- **1,6'-glycosides**: Similar to 1,4'-glycosides, this type also retains a free anomeric carbon, making it a reducing sugar.
- **1,1'-glycosides**: In this case, both sugar units are linked through their anomeric carbons. This means that neither sugar has a free anomeric carbon available for oxidation, making this type a non-reducing sugar.
- **1,5'-glycosides**: This type retains a free anomeric carbon and can also act as a reducing sugar.

4. **Conclusion**:
- The reducing disaccharides among the given types are:
- 1,4'-glycosides
- 1,6'-glycosides
- 1,5'-glycosides
- The non-reducing disaccharide is:
- 1,1'-glycosides

### Final Answer:
The reducing disaccharides are 1,4'-glycosides, 1,6'-glycosides, and 1,5'-glycosides. The non-reducing disaccharide is 1,1'-glycosides.

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