Chapter 22, Problem 8PP

Interpretation Introduction

Interpretation:

The structures of the two different $\gamma -\text{lactones}$ produced by lactonization of D-glucaric acid are to be determined.

Concept introduction:

舧 A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen-oxygen atom ratio of 2:1

舧 ${\text{HNO}}_{\text{3}}$ is an oxidizing agent.

舧 Carbohydrates are oxidized by ${\text{HNO}}_{\text{3}}$ to give aldaric acid as a product.

舧 Aldaric acids are carbohydrates having two carboxylic acids. They are formed due to oxidation reaction of aldoses with dilute ${\text{HNO}}_{\text{3}}$ and their general reaction can be represented as:

舧 Biomolecules containing an ester group ($-\text{O}\text{C}\text{O}$) as part of their ring structures are called lactones. They are derived from their respective hydroxycarboxylic acids. Formation of lactones is called lactonization. They mainly exist as λ and δ forms.

舧 Aldaric acids (obtained from oxidation of aldohexoses) produces lactones of the same order that is as:

舧 The reaction in which there is removal of water molecule is called dehydration reaction.