Chapter 18, Problem 18.69AP

Interpretation Introduction

(a)

Interpretation:

The synthesis of $\text{1-chloro-2, 4-dinitrobenzene}$ from benzene and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid. Electron donating groups substituted on the aromatic ring are those which donate electron to the aromatic ring. Electron donating groups are ortho and para-directing.

Answer to Problem 18.69AP

The reaction of benzene and chlorine gas in the presence of iron chloride followed by nitration forms $\text{1-chloro-2, 4-dinitrobenzene}$ as shown below.

Explanation of Solution

The chlorination of benzene using chlorine gas in the presence of iron chloride forms chlorobenzene which further reacts with nitric acid in the presence of sulphuric acid to give $\text{1-chloro-2, 4-dinitrobenzene}$ as the desired product. The overall reaction is shown below.

Figure 1

Conclusion

The reaction of benzene and chlorine gas in the presence of iron chloride followed by nitration forms $\text{1-chloro-2, 4-dinitrobenzene}$ as shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The synthesis of $\text{1-choloro-3, 5-dinitrobenzene}$ from benzene and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid. Electron donating groups substituted on the aromatic ring are those which donate electron to the aromatic ring. Electron donating groups are ortho and para-directing.

Answer to Problem 18.69AP

The reaction of benzene and nitric acid in the presence of sulphuric acid followed by the treatment with $\text{TCCA}$ in the presence of sulphuric acid forms $\text{1-chloro-2, 4-dinitrobenzene}$ as shown below.

Explanation of Solution

The reaction of benzene and nitric acid in the presence of sulphuric acid forms $\text{1, 3-dinitrobenzene}$ which on further treatment with $\text{TCCA}$ in the presence of concentrated sulphuric acid gives $\text{1-chloro-2, 4-dinitrobenzene}$ as the desired product. The given reaction is shown below.

Figure 2

Conclusion

The reaction of benzene and nitric acid in the presence of sulphuric acid followed by the treatment with $\text{TCCA}$ in the presence of sulphuric acid forms $\text{1-chloro-2, 4-dinitrobenzene}$ as shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The synthesis of diphenylacetylene from $\text{1, 2-diphenylethene}$ and other reagents is to be predicted.

Concept introduction:

The addition of a bromine atom in a compound is known as bromination. Bromination occurs through electrophilic substitution reaction. Bromine atom acts as an electrophile which causes the formation of sigma bond in the reaction.

Answer to Problem 18.69AP

The reaction of $\text{1, 2-diphenylethene}$ and bromine followed by the treatment with ${\text{NaNH}}_{\text{2}}$ forms diphenylacetylene as shown below.

Explanation of Solution

The reaction of $\text{1, 2-diphenylethene}$ and bromine forms $\text{1, 3-dinitrobenzene}$ which on further treatment with ${\text{NaNH}}_{\text{2}}$ gives diphenylacetylene as the desired product. The bromination of alkene takes place in the first step, followed by the elimination of $\text{HBr}$ using a strong basses like ${\text{NaNH}}_{\text{2}}$. The given reaction is shown below.

Figure 3

Conclusion

The reaction of $\text{1, 2-diphenylethene}$ and bromine followed by the treatment with ${\text{NaNH}}_{\text{2}}$ forms diphenylacetylene as shown in Figure 3.

Interpretation Introduction

(d)

Interpretation:

The synthesis of $\text{1-}\left(\text{4-}\left(\text{ethylthio}\right)\text{-3-nitrophenyl}\right)\text{ethanone}$ from chlorobenzene and other reagents is to be predicted.

Concept introduction:

The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as a substitution reaction. In a nucleophilic substitution reaction, nucleophile takes the position of leaving the group by attacking the electron-deficient carbon atom.

Answer to Problem 18.69AP

The reaction of chlorobenzene and acetyl chloride in the presence of ${\text{AlCl}}_{\text{3}}$ followed by nitration and addition of ethylthio group on phenyl ring which gives $\text{1-}\left(\text{4-}\left(\text{ethylthio}\right)\text{-3-nitrophenyl}\right)\text{ethanone}$ as shown below.

Explanation of Solution

The reaction of chlorobenzene and acetyl chloride in the presence of ${\text{AlCl}}_{\text{3}}$ undergoes Friedel-Crafts acylation forms $\text{4-chloroacetophenone}$. In the next step, the reaction between $\text{4-chloroacetophenone}$ and nitric acid in the presence of sulphuric acid followed by nucleophilic substitution to replace chloro by ${\text{SCH}}_{\text{2}}{\text{CH}}_{\text{3}}$ forms the desired product as shown below.

Figure 4

Conclusion

The reaction of chlorobenzene and acetyl chloride in the presence of ${\text{AlCl}}_{\text{3}}$ followed by nitration and addition of ethylthio group on phenyl ring which gives $\text{1-}\left(\text{4-}\left(\text{ethylthio}\right)\text{-3-nitrophenyl}\right)\text{ethanone}$ as shown in Figure 4.

Interpretation Introduction

(e)

Interpretation:

The synthesis of $\text{2-chloro-4, 6-dinitrophenol}$ from chlorobenzene and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid. Electron donating groups substituted on the aromatic ring are those which donate electron to the aromatic ring. Electron donating groups are ortho and para-directing.

Answer to Problem 18.69AP

The reaction of chlorobenzene undergoes nitration followed by the addition of a base which further oxidizes with the help of $\text{NaOCl}$ to form the $\text{2-chloro-4, 6-dinitrophenol}$ as shown below.

Explanation of Solution

The reaction of chlorobenzene and nitric acid in the presence of sulphuric acid undergoes nitration forms $\text{2, 4-dinitrochlorobenzene}$ which further reacts with $\text{NaOH}$ to give $\text{2, 4-dinitrophenol}$. In the final step, the $\text{2, 4-dinitrophenol}$ is treated with $\text{NaOCl}$ forms $\text{2-chloro-4, 6-dinitrophenol}$ as the desired product. The overall reaction is shown below.

Figure 5

Conclusion

The reaction of chlorobenzene undergoes nitration followed by the addition of a base which further oxidizes with the help of $\text{NaOCl}$ to form the $\text{2-chloro-4, 6-dinitrophenol}$ as shown in Figure 5.

Interpretation Introduction

(f)

Interpretation:

The synthesis of butylated hydroxytoluene (BHT) from $p\text{-cresol}$ and other reagents is to be predicted.

Concept introduction:

A chemical reaction that involves the removal of a water molecule from the reacting molecule is known as a dehydration reaction. It takes place in the presence of a strong acid. The percentage of product formed is determined by Saytzeff’s rule.

Answer to Problem 18.69AP

The reaction of $p\text{-cresol}$ and $\text{2-methylprop-1-ene}$ forms compound $\text{BHT}$ as shown below.

Explanation of Solution

The reaction between $p\text{-cresol}$ and $\text{2-methylprop-1-ene}$ in the presence of sulphuric acid forms Butylated hydroxytoulene as the desired product. This reaction is known as dehydration reaction in which ${\text{H}}^{\text{+}}$ acts as a electrophile. The compound Butylated hydroxytoulene commonly known as $\text{BHT}$ which is used in food as an antioxidant.

Figure 6

Conclusion

The reaction of $\text{p-Cresol}$ and $\text{2-methylprop-1-ene}$ forms compound $\text{BHT}$ as shown in Figure 6.

Interpretation Introduction

(g)

Interpretation:

The synthesis of the given product from catechol and other reagents is to be predicted.

Concept introduction:

A chemical reaction that involves the removal of a water molecule from the reacting molecule is known as a dehydration reaction. It takes place in the presence of a strong acid. The percentage of product formed is determined by Saytzeff’s rule.

Answer to Problem 18.69AP

The reaction of catechol and $\text{2-methylprop-1-ene}$ in the presence of sulphuric acid followed by oxidation forms the desired product as shown below.

Explanation of Solution

The reaction of catechol and $\text{2-methylprop-1-ene}$ in the presence of sulphuric acid forms $\text{4-tert-butylbenzene-1, 2-diol}$ which further reacts with ${\text{Ag}}_{\text{2}}\text{O}$ in the presence of ether to give the desired product. The compound ${\text{Ag}}_{\text{2}}\text{O}$ acts as a oxidizing agent in the given reaction.

Figure 7

Conclusion

The reaction of catechol and $\text{2-methylprop-1-ene}$ in the presence of sulphuric acid followed by oxidation forms the desired product as shown in Figure 7.

Interpretation Introduction

(h)

Interpretation:

The synthesis of ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ from bromobenzene and other reagents is to be predicted.

Concept introduction:

Grignard reagents are organometallic compounds which are prepared using alkyl halides in the presence of magnesium metal in dry ether. These reagents act as strong nucleophiles and bases.

Answer to Problem 18.69AP

The reaction of bromobenzene with Grignard reagent and ethylene oxide forms ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ as the desired product. The overall reaction is shown below.

Explanation of Solution

The reaction of bromobenzene with magnesium in the presence of dry $\text{THF}$ forms phenyl magnesium bromide which further treated with ethylene oxide in the presence of dry $\text{THF}$ to give the desired product. In the first step, the Grignard reagent acts as a nucleophile in the given reaction. In the second step, the nucleophilic phenyl ring attacks on the ethylene oxide ring undergoes nucleophilic addition reaction to form the desired product. The overall reaction is shown below.

Figure 8

Conclusion

The synthesis of ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ from bromobenzene as shown inFigure 8.

Interpretation Introduction

(i)

Interpretation:

The synthesis of given product from ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$, fluorobenzene and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid. Electron donating groups substituted on the aromatic ring are those which donate electron to the aromatic ring. Electron donating groups are ortho and para-directing.

Answer to Problem 18.69AP

The reaction of fluorobenzene undergoes nitration followed by the addition of ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ to form the desired product as shown below.

Explanation of Solution

The reaction of fluorobenzene with nitric acid in the presence of sulphuric acid forms $\text{1-fluoro-4-nitrobenzene}$ which further reacts with ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ forms $\text{1-nitro-4-phenethoxybenzene}$. In the given reaction, the nitration of fluorobenzene followed by esterification of with ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ to form the desired product.

Figure 9

Conclusion

The reaction of fluorobenzene undergoes nitration followed by the addition of ${\text{PhCH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ forms $\text{1-nitro-4-phenethoxybenzene}$ as the desired product. The overall synthesis is shown in Figure 9.

Interpretation Introduction

(j)

Interpretation:

The synthesis of the given product from benzene, ethylene group and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid. Electron donating groups substituted on the aromatic ring are those which donate electron to the aromatic ring. Electron donating groups are ortho and para-directing.

Answer to Problem 18.69AP

The synthesis of the desired product from benzene and ethylene group is shown below.

Explanation of Solution

The reaction of benzene with nitric acid in the presence of sulphuric acid forms nitrobenzene which further reacts with bromine to form $\text{3-bromonitrobenzene}$

The styrene is prepared by the bromination of benzene followed by the addition of ethane in the presence of ${\text{PdCl}}_{\text{2}}{\left(\text{tpp}\right)}_{\text{2}}\text{,}{\text{Et}}_{\text{3}}\text{N}$ forms styrene. The formation of styrene is prepared by the Heck reaction.

In the final step, the compound $\text{3-bromonitrobenzene}$ is coupled with styrene by the help of Heck reaction to form the desired product. The overall reaction is shown below.

Figure 10

Conclusion

The synthesis of the desired product from benzene and ethylene group as shown in Figure 10.

Interpretation Introduction

(k)

Interpretation:

The synthesis of the given product from $\text{2-bromonaphthalene}$ and other reagents is to be predicted.

Concept introduction:

The treatment of unsaturated halide with an alkene in the presence of a base and a $\text{Pd}$ catalyst forms a substituted alkene. The chemical reaction involved in this process is known as Heck reaction.

Answer to Problem 18.69AP

The reaction of $\text{2-bromonaphthalene}$ with styrene in the presence of $\text{Pd}{\left(\text{OAc}\right)}_{\text{2}}$ to form the desired product is shown below.

Explanation of Solution

The $\text{2-bromonaphthalene}$ reacts with styrene in the presence of $\text{Pd}{\left(\text{OAc}\right)}_{\text{2}}$ to form the desired product. The Heck reaction is used in the synthesis of the desired product. The Heck reaction is used for cross-coupling reactions between alkenes and aryl halides to form substituted alkenes as shown below.

Figure 11

Conclusion

The reaction of $\text{2-bromonaphthalene}$ with styrene in the presence of $\text{Pd}{\left(\text{OAc}\right)}_{\text{2}}$ to form the desired product as shown in Figure 11.

Interpretation Introduction

(l)

Interpretation:

The synthesis of the given product from bromobenzene, ethylene group and other reagents is to be predicted.

Concept introduction:

Nitration is a process in which an aromatic compound is nitrated by electrophilic substitution in the presence of concentrated sulfuric acid and concentrated nitric acid.

Answer to Problem 18.69AP

The reaction of bromobenzene with nitric acid in the presence of sulphuric acid followed by coupling reaction with allyl alcohol to form the desired product is shown below.

Explanation of Solution

The reaction of bromobenzene with nitric acid in the presence of sulphuric acid forms $\text{4-nitrobromobenzene}$ and undergoes Heck reaction with allyl alcohol to form the desired product. The Heck reaction is used for cross-coupling reactions between alkenes and aryl halides to form substituted alkenes as shown below.

Figure 12

Conclusion

The reaction of bromobenzene with nitric acid in the presence of sulphuric acid followed by coupling reaction with allyl alcohol to form the desired product as shown in Figure 12.

Interpretation Introduction

(m)

Interpretation:

The synthesis of the given product from $\text{PhC}=\text{CH}$, $\text{4-methoxyphenol}$ and other reagents is to be predicted.

Concept introduction:

The hydroxide ions acts as a poor leaving groups as well as strong bases. The tosyl chloride reacts with hydroxide ions in the presence of weak base like pyridine to convert in a good leaving groups.

Answer to Problem 18.69AP

The reaction of $\text{4-methoxyphenol}$ with tosylchloride followed by the addition of phenylacetylene to form the desired product as shown below.

Explanation of Solution

The reaction of $\text{4-methoxyphenol}$ with tosylchloride forms $\text{4-methoxyphenyl}\text{4-methylbenzenesulfonate}$ and undergoes Sonogashira coupling with phenylacetylene forms the desired product. Sonogashira coupling is used to form carbon-carbon bond in the given reaction as shown below.

Figure 13

Conclusion

The reaction of $\text{4-methoxyphenol}$ with tosylchloride followed by the addition of phenylacetylene to form the desired product as shown in Figure 13.

Interpretation Introduction

(n)

Interpretation:

The synthesis of the given product from $\text{1-hexyne}$, resorcinol and other reagents is to be predicted.

Concept introduction:

Sonogashira coupling is used to form carbon-carbon bond in the chemical reaction.

The addition of bromine atom in a compound is known as bromination. Bromination is occurs through elctrophilic substitution reaction. Bromine atom acts as a electrophile which causes the formation of sigma bond in the reaction.

Answer to Problem 18.69AP

The synthesis of the desired product from $\text{1-hexyne}$ and resorcinol is shown below.

Explanation of Solution

The reaction of recorcinol with ${\text{Et}}_{\text{2}}{\text{SO}}_{\text{4}}$ in the presence of a base undergoes bromination to form $\text{1-bromo-2, 4-diethoxybenzene}$. The Sonogashira coupling of $\text{1-bromo-2, 4-diethoxybenzene}$ with $\text{1-hexyne}$ forms $\text{2, 4-diethoxy-1-}\left(\text{hex-1-ynyl}\right)\text{benzene}$. In the final step, the partial hydrogenation of alkyne in the presence of Ruthenium catalyst takes place to form the desired product. The overall reaction is shown below.

Figure 14

Conclusion

The synthesis of the desired product from $\text{1-hexyne}$ and resorcinol is shown in Figure 14.

Interpretation Introduction

(o)

Interpretation:

The synthesis of the given product from iodobenzene and other reagents is to be predicted.

Concept introduction:

The coupling reactions used to connect two compounds with the help of a metal catalyst like palladium. Sonogashira coupling is used to form a carbon-carbon bond in the chemical reaction.

Answer to Problem 18.69AP

The synthesis of the desired product from iodobenzene and cyclohexene is shown below.

Explanation of Solution

The reaction of iodobenzene with cyclohexene in the presence of $\text{Pd}{\left(\text{OAc}\right)}_{\text{2}}$ catalyst forms $\text{cyclohex-2-enylbenzene}$ which further reacts with $\text{m-chloroperbenzoic}\text{acid}$ to form desired epoxide compound as shown below.

Figure 15

Conclusion

The synthesis of the desired epoxide compound from iodobenzene and cyclohexene is shown below in Figure 15.