Chapter 24, Problem 24.38AP

Interpretation Introduction

(a)

Interpretation:

The structure of all the $2-$ ketohexose is to be drawn.

Concept introduction:

The simple sugars are monosaccharides having five or six carbon atoms as in fructose and glucose. At carbon $-1$, the functional group normally present is aldehyde. Based on the symmetry of carbon atom their structure can be drawn.

Interpretation Introduction

(b)

Interpretation:

The structure of an achiral ketopentose ${\text{C}}_5{\text{H}}_{10}{\text{O}}_5$ is to be drawn.

Concept introduction:

A carbon atom is said to be chiral when all four atoms attached to it are different. It is also known as asymmetric carbon atom. Similarly when a molecule cannot be divided into two similar parts it is known as chiral or asymmetrical. When a molecule has a plane of symmetry, it is considered to be achiral. It means that molecule can be divided into two equal parts through the plane of symmetry.

Interpretation Introduction

(c)

Interpretation:

The structure of $\alpha -\text{D}-\text{galactofuranose}$ is to be drawn.

Concept introduction:

Two isomers have same formula but different structures. In case of sugars, two isomers are possible on the basis of functional group present in the molecule. In pentose and hexose sugar they may be open ring structure with aldehyde group or close ring structures with keto group as main functional groups (keto, aldo isomers).

Interpretation Introduction

(d)

Interpretation:

The structure of $\beta -\text{D}-\text{idofuranose}$ is to be drawn.

Concept introduction: Two isomers have same chemical formula but different structures. In case of sugars two isomers are possible on the basis of functional group present.( They may be open ring with aldehyde or close ring with keto group as their functional group.