Chapter 25, Problem 25.80P

Synthesize each compound from benzene. Use a diazonium salt as one of the synthetic intermediates.

a. c. e.

b. d. f.

Interpretation Introduction

(a)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Explanation of Solution

In the first step of the synthesis, nitration of benzene ring takes place. The nitro group is meta directing, as a result the chlorination takes place at meta position in the second step. The nitro group converts to amine group on reaction with $\text{Sn/HCl}$. In the next step, diazonium salt is formed which on reaction with $\text{CuCN}$ followed by hydrolysis gives desired compound. The complete synthesis of given compound is shown in Figure 1.

Figure 1

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Explanation of Solution

In the first step of the synthesis, nitration of benzene ring takes place. The nitro group is meta directing, as a result the chlorination takes place at meta position in the next two steps. The nitro group converts to amine group on reaction with $\text{Sn/HCl}$. In the next step, diazonium salt is formed which on hydrolysis gives desired compound. The complete synthesis of given compound is shown in Figure 2.

Figure 2

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Explanation of Solution

The first step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 3

In the above step, benzene undergoes Friedel craft’s alkylation reaction to form toluene. It further reacts with ${\text{HNO}}_{\text{3}}$ in the presence of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ to form nitro compound, which on reduction produces $p-$ toluidine.

The second step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 4

The compound $p-$ toluidine reacts with ${\text{NaNO}}_{\text{2}}$ in the presence of $\text{HCl}$ to form diazonium salt, which reacts with $\text{CuCN}$ to give $4-$ methylbenzonitrile.

The third step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 5

In the last step, the reduction of nitrile to amine takes place in the presence of ${\text{LiAlH}}_{\text{4}}$, followed by addition of water to form the final product.

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 3, Figure 4 and Figure 5.

Interpretation Introduction

(d)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of a nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Explanation of Solution

The first step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 6

In the above step, benzene undergoes Friedel craft’s alkylation reaction to form ethylbenzene. It further reacts with ${\text{HNO}}_{\text{3}}$ in the presence of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ to form nitro compound, which on reduction produces $p-$ ethylaniline.

The second step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 7

The compound $p-$ ethylaniline reacts with ${\text{NaNO}}_{\text{2}}$ in the presence of $\text{HCl}$ to form diazonium salt, which reacts with $\text{CuCN}$ to give $4-$ ethylbenzonitrile.

The third step of synthesis of given compound from benzene, by the use of a diazonium salt as one of the synthetic intermediates, is shown below.

Figure 8

In the last step, the hydrolysis reaction takes place, which results in the formation of $4-$ ethylbenzoic acid.

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 6, Figure 7 and Figure 8.

Interpretation Introduction

(e)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Explanation of Solution

In the first step of the synthesis, nitration of benzene ring takes place. The nitro group is meta directing, as a result the bromination takes place at meta position in the second step. The nitro group converts to amine group on reaction with $\text{Sn/HCl}$. In the next step, diazonium salt is formed which on hydrolysis gives $3$-bromophenol. In the last step, Friedel-Craft alkylation takes place. The methyl group attaches at the para position to hydroxyl group and ortho to bromine group. The complete synthesis of given compound is shown in Figure 9.

Figure 9

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 9.

Interpretation Introduction

(f)

Interpretation: The given compound is to be synthesized from benzene by the use of diazonium salt as one of the synthetic intermediates.

Concept introduction: Amines are the derivatives of ammonia consisting of a nitrogen atom with the lone pair of electrons. They are basic compounds. The synthesis of the products relies upon the type of reactants and reagents that are used during the reactions. The reagents perform numerous functions in reactions like proton abstraction, oxidation, reduction, catalysis, and dehydrogenation.

Answer to Problem 25.80P

The synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates is shown below.

Explanation of Solution

The first step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 10

In the above step, benzene reacts with ${\text{HNO}}_3$ in the presence of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ to form nitro compound.

The second step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 11

Nitrobenzene undergoes chlorination and reduction reaction to form $3,5-$ dichloroaniline, which undergoes diazotization reaction to form a diazonium salt.

The third step of synthesis of given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown below.

Figure 12

In the last step, $3,5-$ dichlorobenzenediazonium salt reacts with aniline to form the final product.

Conclusion

The synthesis of a given compound from benzene, by the use of diazonium salt as one of the synthetic intermediates, is shown in Figure 10, Figure 11 and Figure 12.