Chapter 14.2, Problem 14.8P

(a)

Interpretation Introduction

Interpretation:

An example of an aldopentose has to be given that is a D sugar.

Concept Introduction:

Simplest carbohydrates are known as monosaccharides.  They contain three to six carbons generally in a chain form with a carbonyl group present in the terminal or the adjacent carbon atom from the terminal.  Monosaccharides that have the carbonyl group at the terminal carbon atom $\text{C1}$ are known as aldoses and the monosaccharides that have the carbonyl group on the adjacent carbon atom $\text{C2}$ are known as ketoses.

The number of carbon atoms present in the chain characterize the monosaccharide.  They are given below.

• Carbon chain with three carbon atoms is triose.
• Carbon chain with four carbon atoms is tetrose.
• Carbon chain with five carbon atoms is as pentose.
• Carbon chain with six carbon atoms is as hexose.

A carbon atom that is bonded to four different groups is known as a chiral carbon atom.  This can rotate the plane polarized light.  D- and L- isomers of monosaccharide can be identified by looking into the chiral center that is farther from the carbonyl group.  In a Fischer projection, if the $\text{OH}$ group is present on the right side in the chiral center that is farthest from the carbonyl group means it is a D monosaccharide and if the $\text{OH}$ group is present on the left side means it is a L monosaccharide.

(b)

Interpretation Introduction

Interpretation:

An example of a ketohexose has to be given that is a D sugar.

Concept Introduction:

Refer part (a).

(c)

Interpretation Introduction

Interpretation:

An example of a ketotetrose has to be given that is a D sugar.

Concept Introduction:

Refer part (a).