Chapter 21, Problem 21.53P

Interpretation Introduction

(a)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{H}}_{\text{2}}{\text{O, H}}^{+}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

The esters in acidic condition undergo hydrolysis and form the corresponding carboxylic acid and alcohol.

Answer to Problem 21.53P

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{H}}_{\text{2}}{\text{O, H}}^{+}$ is

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with ${\text{H}}_{\text{2}}{\text{O, H}}^{+}$ is

The methyl cyclohexylmethanoate is an ester; in an acidic condition, it undergoes hydrolysis to form carboxylic acid and alcohol. The ester is activated by protonation of carbonyl oxygen. The water molecule acts as a nucleophile and attacks the carbonyl carbon of protonated ester and removes methanol as the leaving group. The product with detailed mechanism is as follows:

Conclusion

The product with detailed mechanism for the given reaction is drawn based on the reactivity of ester in an acidic condition.

Interpretation Introduction

(b)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{H}}_{\text{2}}{\text{O, H}}^{+}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

The ester can be hydrolyzed in basic condition and forms corresponding carboxylic acid and alcohol. As hydrolysis occurs in basic condition, it deprotonates carboxylic acid to carboxylate ion. Thus, to recover, it must then be treated with an acid.

Answer to Problem 21.53P

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{H}}_{\text{2}}{\text{O, OH}}^{-}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with ${\text{H}}_{\text{2}}{\text{O, OH}}^{-}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is

The methyl cyclohexylmethanoate is an ester; in a basic condition, it undergoes hydrolysis to form carboxylic acid and alcohol. The hydroxide ion acts as a nucleophile and attacks ester carbonyl to form an intermediate having negatively charged oxygen. The intermediate undergoes elimination of methoxide by delocalization of lone pair of negatively charged oxygen and forms carboxylic acid. The carboxylic acid further undergoes deprotonated to carboxylate ion due to basic reaction condition. Therefore, the carboxylic acid is recovered by addition of ${\text{H}}_{\text{3}}{\text{O}}^{+}$. The product with detailed mechanism is as follows:

Conclusion

The product with detailed mechanism for the given reaction is drawn based on the reactivity of ester in a basic condition.

Interpretation Introduction

(c)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{OH, CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{ONa}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

The alcohols are weak nucleophiles and thus cannot react with an ester under normal condition. Thus, on addition of base, the alcohol is converted to alkoxide ion, which acts as a good nucleophile and undergoes transesterification when reacted with an ester.

Answer to Problem 21.53P

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{OH, CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{ONa}$ is

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{OH, CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{ONa}$ is

The methyl cyclohexylmethanoate is an ester; on reaction with ${\text{R'OH/R'O}}^{-}$, it undergoes transesterification where the alkoxy group of an ester is substituted by nucleophilic ${\text{R'O}}^{-}$ group. The ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{O}}^{-}$ ion prepared from propanol acts as a nucleophile and attacks on ester carbonyl to form an intermediate having negatively charged oxygen. The intermediate undergoes elimination of methoxide by delocalization of lone pair of negatively charged oxygen and forms a new ester molecule. The product with detailed mechanism is as follows:

Conclusion

The product with detailed mechanism for the given reaction is drawn based on the reactivity of ester with alkoxide ion.

Interpretation Introduction

(d)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{propan-2-ol, H}}^{+}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

Alcohols are weak nucleophiles and cannot react with an ester under normal condition. Thus, for the reaction to carry out, it can be catalyzed by addition of an acid. The ester, on acid-catalyzed reaction with alcohol, undergoes transesterification, called acid-catalyzed transesterification.

Answer to Problem 21.53P

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and ${\text{propan-2-ol, H}}^{+}$ is

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with ${\text{propan-2-ol, H}}^{+}$ is

The methyl cyclohexylmethanoate is an ester; on reaction with ${\text{R'OH/R'O}}^{-}$, it undergoes transesterification. The ester is activated by protonation of carbonyl oxygen. The alcohol molecule acts as a nucleophile and attacks carbonyl carbon of the protonated ester and removes methanol as the leaving group. The product with detailed mechanism is as follows:

Conclusion

The product with detailed mechanism for the given reaction is drawn based on the reactivity of ester with alcohol in an acidic condition.

Interpretation Introduction

(e)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and $\text{propan-2-amine}$ (excess) ${\text{, H}}^{+}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

The ester, on reaction with an excess of amine in an acidic condition, undergoes aminolysis and produces an amide product by removing alkoxy group of ester.

Answer to Problem 21.53P

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and $\text{propan-2-amine}$ (excess) ${\text{, H}}^{+}$ is

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with $\text{propan-2-amine}$ (excess) ${\text{, H}}^{+}$ is

The methyl cyclohexylmethanoate is an ester; in an acidic condition, it undergoes aminolysis to form amide and alcohol. The ester is activated by protonation of carbonyl oxygen. The amine molecule acts as a nucleophile and attacks the carbonyl carbon of protonated ester and removes methanol as the leaving group. The product with detailed mechanism is as follows:

Conclusion

The product with detailed mechanism for the given reaction is drawn based on the reactivity of ester with amine in an acidic condition.

Interpretation Introduction

(f)

Interpretation:

The product with detailed mechanism for the reaction between methyl cyclohexylmethanoate and $\text{propan-1-ol}$ is to be drawn by identifying if the reaction occurred.

Concept introduction:

The alcohols are weak nucleophiles; in an acidic or basic condition, they undergo transesterification with an ester, but under normal condition, the reaction does not occur.

Answer to Problem 21.53P

No reaction takes place between methyl cyclohexylmethanoate and $\text{propan-1-ol}$, and it is indicated as

Explanation of Solution

The equation for the reaction of methyl cyclohexylmethanoate with $\text{propan-1-ol}$ is

The methyl cyclohexylmethanoate is an ester, and the given reagent $\text{propan-1-ol}$ is an alcohol. The reaction is not catalyzed by acid or a base. As the alcohols are weak nucleophiles, they do not react with an ester under uncatalyzed reaction condition. Therefore, methyl cyclohexylmethanoate cannot react with $\text{propan-1-ol}$ and is indicated as

Conclusion

It is determined that there is no reaction between methyl cyclohexylmethanoate and $\text{propan-1-ol}$ as the alcohols are unreactive with an ester under normal condition.