Chapter 17, Problem 17.34UKC

(a)

Interpretation Introduction

Interpretation:

The structure of the ester formed by the reaction two molecules of the given amino acid has to be drawn.

Concept Introduction:

Esterification reaction: Esters are prepared by the reaction of a carboxylic acid and an alcohol molecule with the elimination of water molecule. The addition of a strong acid such as ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is used to increase the rate of reaction. Here, the $-OH$ group is attached to the carbonyl carbon atom of the carboxylic acid is being replaced by $-OR\text{'}$ the in the alcohol forming ester and water.

(b)

Interpretation Introduction

Interpretation:

The structure of the amide formed by the reaction two molecules of the given amino acid has to be drawn.

Concept Introduction:

Amide Formation: Amide is formed when a carboxylic acid reacts with an amine or ammonia.

Here, the $-OH$ group is attached to the carbonyl carbon atom of the carboxylic acid is being replaced by $-N{H}_2$, $-NHR\text{'}$ or $-NR{\text{'}}_2$ group in the an amine or ammonia forming amide and water.

• Primary amide is produce when a carboxylic acid reacts with ammonia.
• Secondary and tertiary amide is produce when a carboxylic acid reacts with primary and secondary amine respectively.
• Ammonium salt is formed when tertiary amine and a carboxylic acid reacts forming an ionic compound with a carboxylate acid anion and a trialkyl ammonium cation since there is no hydrogen atom in trialkyl amine

(c)

Interpretation Introduction

Interpretation:

The structure of the cyclic ester formed by the intramolecular reaction of the given amino acid has to be drawn

Concept introduction:

Lactones: They are cyclic esters where the carbonyl carbon part of carboxylic acid group and oxygen part of alcohol group of the same compound attaches forming a ring.

Ester Hydrolysis: Ester hydrolysis can be caused by acid and base.

• Acid-catalyzed hydrolysis: In presence of strong acid such as ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$, ester reacts wither water to form the corresponding alcohol and carboxylic acid. T s the reverse of esterification.
• Saponification: Ester hydrolysis taking place in presence of base such as $NaOH$ or $KOH$ is known as saponification. Ester reacts with hydroxide ion forming carboxylic acid which again reacts with base resulting in the formation of a caboxylate anion.