Chapter 24, Problem 76PP

(a)

Interpretation Introduction

Interpretation:

Reducing sugar property of salicin should be identified.

Concept introduction:

Reducing sugar: Sugars that contain aldehyde or a free ketone groups that are oxidized to carboxylic acids are classified as reducing sugars.

(b)

Interpretation Introduction

Interpretation:

Products should be identified when salicin is hydrolyzed in the presence of an acid

Concept introduction:

Acid: acid hydrolysis the ethers which produces alcohols.

(c)

Interpretation Introduction

Interpretation:

Structure ofsalicin (α-glycoside or β-glycoside) should be identified.

Concept introduction:

The Haworth projection: A Haworth projection is a three-dimensional representation of monosaccharides and the structural formula is inscription as a cyclic structures.

In Haworth projection, oxygen atom is placed in back right corner, ${\text{CH}}_{\text{2}}\text{OH}$ is arranged up at the C5 carbon atom. Anomeric hydroxyl group is placed down if it is α-anomer which is trans to the ${\text{CH}}_{\text{2}}\text{OH}$ of C5 carbon. Anomeric hydroxyl group is placed up if it is β-anomer which is cis to the ${\text{CH}}_{\text{2}}\text{OH}$ of C5 carbon.  The remaining hydroxyl group is placed up if the hydroxyl group left side in Fischer projection. Hydroxyl group is placed down if the hydroxyl group right side in Fischer projection

(d)

Interpretation Introduction

Interpretation:

Major product should be identified when salicin is reaction with excess acetic anhydride in the pyridine.

Concept introduction:

Acetylation: carbohydratesacetylatedby using acetic anhydride in pyridine.

(e)

Interpretation Introduction

Interpretation:

Mutarotation property of salicin should be identified when dissolved in neutral water.

Concept introduction:

Acid: acid hydrolysis the ethers which produces alcohols.

Mutarotation: Change in the optical rotation because change inequilibrium between the α-anomer and β-anomer when the stereocenters interconvert.

The optical rotation of the solution mainly depends on the optical rotation of the α-anomer and β-anomer and ratio in the solution.