Chapter 24, Problem 24.29SP

(a)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Ninhydrin reacts with alpha amino acids to give resonance stablised anion known as Ruhemann’s purple accompanied by evolution of carbon dioxide. The side chain of amino acid is lost as an aldehyde. This reaction is used to detect amino acids on a wide range of substrates.

(b)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Carboxyl benzyl is used to protect the amine group of amino acids. Its symbol is Cbz. It is used in the synthesis of amides.

(c)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Acetic anhydride is commonly used for acylation of amino acids. All sorts of acylating agents can react with amino group of amino acids. Amino acids contain two major functional groups: the amino group and the carboxylate group.

(d)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Acetic anhydride is commonly used for acylation of amino acids. All sorts of acylating agents can react with amino group of amino acids. Amino acids contain two major functional groups: the amino group and the carboxylate group.

(e)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Nucleophilic addition takes place when hydrogen cyanide reacts with aldehyde or ketones. Hydrogen cyanide attacks the carbonyl group of aldehydes and ketones to form cyanohydrin. It undergoes acidic hydrolysis to give carboxylic acid.

(f)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Nucleophilic addition takes place when hydrogen cyanide reacts with aldehyde or ketones. Hydrogen cyanide attacks the carbonyl group of aldehydes and ketones to form cyanohydrin. It undergoes acidic hydrolysis to give carboxylic acid.

(g)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Carboxylic acids react with bromine and phosphorus tribromide to give $\alpha$-bromo acyl bromide. This intermediate is hydrolysed to give $\alpha$-bromo acids. The reaction mechanism is acid-catalysed $\alpha$ halogenation. The enol form of the acid acts as a nucleophilic intermediate.

(h)

Interpretation Introduction

To determine: The product of the given reaction.

Interpretation: The product of the given reaction is to be stated.

Concept introduction: Carboxylic acids react with bromine and phosphorus tribromide to give $\alpha$-bromo acyl bromide. This intermediate is hydrolysed to give $\alpha$-bromo acids. These $\alpha$-bromo acids react with excess of ammonia to give amino acids.