Chapter 19, Problem 19.48AP

Interpretation Introduction

(a)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

Oxime belongs to the family of imines. The formula of oxime is $\text{R<msup> R <mo>′</mo></msup> C=NOH}$. Types of oxime are ketoxime and aldoxime. The preparation of oxime proceeds through a nucleophilic addition reaction. The catalyst acts as a nucleophile in the reaction.

Answer to Problem 19.48AP

The product formed in the given reaction is cyclohexanone oxime in the presence of hydroxylamine and pyridine. The reaction is shown below.

Explanation of Solution

Cyclohexanone reacts with hydroxylamine to form the derivative of the oxime of the carbonyl compound. The nucleophilic addition takes place in the given reaction. The hydroxylamine is used as a nucleophile. The corresponding chemical reaction is shown below.

Figure 1

Conclusion

The product formed in the given reaction is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

The reaction between ketone and alcohol in the presence of $p-\text{toluene}\text{sulfonic}\text{acid}$ is a nucleophilic substitution reaction. The substituted alcohol and methoxy group is obtained as a product.

Answer to Problem 19.48AP

The product obtained in the given reaction is shown below.

Explanation of Solution

In the given reaction, $\text{4-}$ methyl-cyclohexanone reacts with methanol to give the product in the presence of $p-\text{toluene}\text{sulfonic}\text{acid}$. The name of the product is $\text{1-methoxy-4-methylcyclohexanol}$. This is a nucleophilic substitution reaction.

Figure 2

Conclusion

The treatment of $\text{4-}$ methyl-cyclohexanone with methanol to give the product in the presence of $p-\text{toluene}\text{sulfonic}\text{acid}$ as shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

Ketones react with diols to form acetals. This reaction is generally used as a way of protecting the carbonyl group in reactions. The carbonyl group can be generated back by hydrolysis of the acetal. Aldehydes react with diols to form hemiacetals. The reaction takes place in the presence of an acid. The formation of acetals and hemiacetals is a type of nucleophilic substitution reaction.

Answer to Problem 19.48AP

The product formed in the given reaction is a hemiacetal as shown below.

Explanation of Solution

In the third reaction, the methylglyoxal reacts with $\text{HCl}$ in the presence of methanol. The keto group is less reactive than the aldehyde group. Therefore, substitution is takes place at the aldehydic position.

Figure 3

Conclusion

The reaction between methylglyoxal and $\text{HCl}$ gives hemiacetal as the product as shown in Figure 3.

Interpretation Introduction

(d)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

The cyclic ethers are ring compounds which contain nitrogen, sulfur and oxygen groups within the ring. The easy method for synthesis of cyclic ether is Williamson synthesis. Epoxides undergo nucleophilic ring-opening reactions which are acid-catalyzed. If the epoxide is unsymmetrical, then the anionic nucleophile will attack the less-hindered carbon atom of the ring. If the reaction conditions are acidic, then the reaction will occur at the more substituted carbon atom.

Answer to Problem 19.48AP

The product formed when the $\text{1, 9-dihydroxy-2, 8-dimethylnonan-5-one}$ is reacted with substituted benzene is shown below.

Explanation of Solution

The compound $p\text{-toluene}\text{sulfonic}\text{acid}$ is also known as tosyl group which is act as a dehydrating agent.

When acid is treating with $\text{1, 9-dihydroxy-2, 8-dimethylnonane-5-one}$ then the product formed is a cyclic ether. The ring-closing takes place and form a cyclic ether as a product. The reaction proceeds in the presence of

Figure 4

Conclusion

The product formed on the treatment of $\text{1, 9-dihydroxy-2, 8-dimethylnonane-5-one}$ with $p\text{-toluene}\text{sulfonic}\text{acid}$ as shown in Figure 4.

Interpretation Introduction

(e)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

Grignard reagents are organometallic compounds which are prepared by using alkyl halides in the presence of magnesium metal in dry ether. These reagents act as strong nucleophiles and bases. The Grignard reagent is used to increase the chain length of the carbon-carbon bond.

Answer to Problem 19.48AP

The compound $\text{1-Pheny-1-propan-1-one}$ reacts with phenylmagnesium bromide to give the product shown below.

Explanation of Solution

The compound $\text{1-Pheny-1-propan-1-one}$ reacts with phenylmagnesium bromide followed by hydrolysis. The product formed is tertiary alcohol as a major product. The Grignard reagent acts as a reducing agent and ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ is used for hydrolysis.

Figure 5

Conclusion

The reaction between $\text{1-Pheny-1-propan-1-one}$ and phenylmagnesium bromide is shown in Figure 5.

Interpretation Introduction

(f)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

The conversion of an aldehydic or ketonic group to alkene with the help of Wittig reagent is known as Wittig reaction.. The chemical name of Wittig reagent is triphenyl phosphonium ylide. The Wittig reagent gives good yields of alkene even when other functional groups are present on the aldehydes or ketone. However, as the steric hindrance of the aldehydes or ketone increases, the yield of the alkene decreases.

Answer to Problem 19.48AP

The product formed in the given reaction is $\text{ethene-1, 1-diylidibenzene}$ as shown below.

Explanation of Solution

The carbonyl compounds react with Wittig reagent. The product formed is alkenes. In this Wittig reaction, most of the ketone reacts with triphenyl phosphonium ylide to generate an alkene and triphenylphosphine oxide as shown below.

Figure 6

Conclusion

The treatment of haloalkane with triphenylphosphine gives the product $\text{ethene-1, 1-diylidibenzene}$ as shown in Figure 6.

Interpretation Introduction

(g)

Interpretation:

The product formed in the given reaction is to be stated.

Concept introduction:

The Wittig reaction is the chemical reaction involves a change in an aldehyde or ketone converted into an alkene. The chemical name of Wittig reagent is triphenyl phosphonium ylide. The Wittig reagent gives good yields of alkene even when other functional groups are present on the aldehydes or ketone. However, as the steric hindrance of the aldehydes or ketone increases, the yield of alkene decreases.

Answer to Problem 19.48AP

The product formed in the given reaction is shown below.

Explanation of Solution

The reaction is Wittig reaction. The reagent used is is triphenyl phosphonium ylide.

In the first step, the treatment of triphenyl phosphonium ylide reacts with $\text{1, 8-bis}\left(\text{bromomethyl}\right)\text{biphenylene}$ takes place. In the second step, the carbanion is formed in the presence of phenyllithium. In the final step, the carbanion formed in second step is treated with glyoxal to form the desired product. The product formed is $\left(\text{Z}\right)\text{-1, 4-dihydrocycloocta}\left[\text{def}\right]\text{biphenylene}$ as shown below.

Figure 7

Conclusion

The given reaction is shown in Figure 7 in the presence of Wittig reagent.