Chapter 22, Problem 22.40P

(a)

Interpretation Introduction

Interpretation:

The preparation of the 1-bromo-3-nitrobenzene from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Nitration of benzene ring by the reaction of benzene with nitrating mixture.

Step 2: Halogenation of nitrobenzene by the reaction of nitrobenzene with bromine in the presence of Lewis acid.

(b)

Interpretation Introduction

Interpretation:

The preparation of the 1-bromo-4-nitrobenzene from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Halogenation of benzene by the reaction of benzene with bromine in the presence of Lewis acid.

Step 2: Nitration of bromobenzene by the reaction of bromobenzene with nitrating mixture.

(c)

Interpretation Introduction

Interpretation:

The preparation of the 2,4-6-trinitrotoluene from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Methyl group in toluene is an activating and ortho-para directing group, so three times nitration of toluene gives the target compound.

(d)

Interpretation Introduction

Interpretation:

The preparation of the m-chlorobenzoic acid from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Oxidation of toluene with chromic acid gives the benzoic acid.

Step 2: Carboxyl group is a deactivating and meta directing group so the chlorination takes place at the meta position.

(e)

Interpretation Introduction

Interpretation:

The preparation of the p-chlorobenzoic acid from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Halogenation of toluene by the reaction of toluene with chlorine in the presence of Lewis acid.

Step 2: Oxidation of 4-chlorotoluene by chromic acid gives the target compound.

(f)

Interpretation Introduction

Interpretation:

The preparation of the p-dichlorobenzene from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Halogenation of benzene by the reaction of benzene with chlorine in the presence of Lewis acid.

Step 2: Second halogenation of chlorobenzene by the reaction of chlorobenzene with chlorine in the presence of Lewis acid.

(g)

Interpretation Introduction

Interpretation:

The preparation of the 1-bromo-4-nitrobenzene from benzene or toluene or phenol has to be shown.

Concept Introduction:

Activating and deactivating groups:

The effect of substituents on the reaction rate of aromatic electrophilic substitution is given by activating or deactivating groups.

Activating groups – ortho/para directing groups.  The rate of reaction is increased by an activating groups (electron donating groups) relative to hydrogen.

Deactivating groups – metadirecting groups.  The rate of reaction is decreased by a deactivating groups (electron withdrawing groups) relative to hydrogen.

Explanation of Solution

Given target compound,

Step 1: Nitration of benzene by the reaction of benzene with nitrating mixture.

Step 2: Sulfonation of nitrobenzene by the reaction with ${\text{SO}}_{\text{3}}$ and ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$.