Q. 13.40 - An Introduction to General, Organic, and Biological Chemistry

Question

Draw the Fischer projection for the oxidation and the reduction products of D-ribose. What are the names of the sugar acid and the sugar alcohol produced?

Step-by-Step Solution

Answer

The oxidation and reduction of the products is 

Step 1 : Given information

The structure is 

Step 2 : An Introduction

Redox reactions occur when the oxidation states of the substrate change. The loss of electrons or an increase in the oxidation state of a chemical or atoms within it is referred to as oxidation. Reduction is the addition of electrons or a reduction in the oxidation state of a chemical or its atoms. 

Step 3: Determine the Fisher projection model

Emil Fischer created the Fischer projection model, which shows the three-dimensional structure of enantiomers. 

The horizontal lines in the structure represent forward bonds, whereas the vertical lines represent backward bonds from a carbon atom.

The top is most likely oxidised carbon, and the core carbon atom to which the other groups are linked is often chiral carbon.

The location of the hydroxyl group $-OH$ in the structure distinguishes the levo rotatory (L) and dextro rotatory (D) versions of enantiomers.

The L-isomer is represented by drawing the hydroxyl group linked to the chiral carbon to the left. The $D$-isomer is shown by drawing the hydroxyl group to the right.

Step 4: Determine the oxidation and reduction products

D-ribose is a sugar with five carbons. Alcohols are formed when aldehydes are reduced, while carboxylic acids are formed when aldehydes are oxidised.

D-ribose is reduced (added hydrogen) to form $D$ribitol, a five-carbon alcohol. D-ribose is oxidised (added oxygen) to form$D$ ribonic acid.

Step 5: Determine the Structure

The oxidation and reduction products are