Write a mechanism for each of the following reactions:

a. the uncatalyzed hydrolysis of methyl propionate.

Write a mechanism for each of the following reactions:

b. the aminolysis of phenyl formate, using methylamine.

Which ester hydrolyzes more rapidly? a. methyl acetate or phenyl acetate?

Which ester hydrolyzes more rapidly? b. phenyl acetate or benzyl acetate?

In the mechanism for the acid-catalyzed hydrolysis of an ester,

c. what species is HB⁺ most likely to be in the hydrolysis reaction?

d. what species is HB⁺ most likely to be in the reverse reaction?

Using the mechanism for the acid-catalyzed hydrolysis of an ester as your guide, write the mechanism—showing all the curved arrows—for the acid-catalyzed reaction of acetic acid and methanol to form methyl acetate. Use HB⁺ and :B to represent the proton-donating and proton-removing species, respectively.

What products are formed from the acid-catalyzed hydrolysis of the following esters?

a.

b.

Show the mechanism for the acid-catalyzed formation of 23c starting with the product obtained from its hydrolysis.

What products are obtained from the following reactions? b. phenyl acetate + excess ethanol + HCl

Write the mechanism for the acid-catalyzed transesterification of ethyl acetate with methanol.

Write the mechanism for the acid-catalyzed reaction of tert-butyl acetate with methanol.

b. Explain why the rate of aminolysis of an ester cannot be increased by H⁺.

b. Explain why the rate of aminolysis of an ester cannot be increased by HO⁻, or RO⁻.

D. N. Kursanov, a Russian chemist, proved that the bond that is broken in the hydroxide-ion-promoted ­hydrolysis of an ester is the acyl C—O bond, rather than the alkyl C—O bond, by studying the hydrolysis of the following ester under basic conditions:

a. What products contained the ¹⁸O label?

b. What product would have contained the ¹⁸O label if the alkyl C—O bond had broken?

Show how each of the following esters could be prepared using a carboxylic acid as one of the starting materials:

a. methyl butyrate (odor of apples)

Propose a mechanism for the following reaction. (Hint: Number the carbons to help you see where they end up in the product.)

What acyl chloride and amine are required to synthesize the following amides?

a. N-ethylbutanamide

b. N,N-dimethylbenzamide

Which of the following reactions lead to the formation of an amide?

Write the mechanism for the acid-catalyzed reaction of an amide with an alcohol to form an ester.

Rank the following amides from greatest reactivity to least reactivity toward acid-catalyzed hydrolysis:

What alkyl bromide would you use in a Gabriel synthesis to prepare each of the following amines?

a. pentylamine

What alkyl bromide would you use in a Gabriel synthesis to prepare each of the following amines?

b. isohexylamine

What alkyl bromide would you use in a Gabriel synthesis to prepare each of the following amines?

c. benzylamine

What alkyl bromide would you use in a Gabriel synthesis to prepare each of the following amines?

d. cyclohexylamine

Which alkyl halides form the carboxylic acids listed here after reaction with sodium cyanide followed by heating the product in an acidic aqueous solution?

a. butyric acid

b. isovaleric acid

Propose a mechanism for the reaction of acetic anhydride with water.

We saw that acid anhydrides react with alcohols, water, and amines. In which of these reactions can the tetrahedral intermediate eliminate the carboxylate ion even if it does not lose a proton before the elimination step? Explain.

Propose a mechanism for the formation of succinic anhydride from succinic acid in the presence of acetic anhydride at neutral pH.

How does acetic anhydride make it easier to form the anhydride?

How could you synthesize the following compounds starting with a carboxylic acid?

b.