BackThere are many methods for activating a carboxylic acid in preparation for coupling with an amine. The following method converts the acid to an N-hydroxysuccinimide (NHS) ester.
(a) Explain why an NHS ester is much more reactive than a simple alkyl ester.
Grignard reagents add to carbonate esters as they add to other esters.
(c) Diethyl carbonate is a liquid reagent that is easy to handle. Also show how you might use diethyl carbonate instead of methyl isocyanate to make Sevin® insecticide.
Suggest the most appropriate reagent for each synthesis, and explain your choice.
(d)
Predict the products of the following reactions.
(d) anisole + succinic anhydride and aluminum chloride
Show how you would accomplish the following multistep syntheses. You may use any additional reagents and solvents you need.
(e)
Write the mechanism for each of the following reactions:
a. the reaction of acetyl chloride with water to form acetic acid
How would you make the following compounds from N-benzylbenzamide?
c. benzyl alcohol
The reaction of a nitrile with an alcohol in the presence of a strong acid forms an N-substituted amide. This reaction, known as the Ritter reaction, does not work with primary alcohols.
a. Propose a mechanism for the Ritter reaction.
The reaction of a nitrile with an alcohol in the presence of a strong acid forms an N-substituted amide. This reaction, known as the Ritter reaction, does not work with primary alcohols.
b. Why does the Ritter reaction not work with primary alcohols?
The reaction of a nitrile with an alcohol in the presence of a strong acid forms an N-substituted amide. This reaction, known as the Ritter reaction, does not work with primary alcohols.
c. How does the Ritter reaction differ from the acid-catalyzed hydrolysis of a nitrile to form an amide?
a. Which of the following reactions does not give the carbonyl product shown?
b. Which of the reactions that do not occur can be made to occur if an acid catalyst is added to the reaction mixture?
5.
a. Which of the following reactions does not give the carbonyl product shown?
b. Which of the reactions that do not occur can be made to occur if an acid catalyst is added to the reaction mixture?
9.
10.
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−.
a. Rank the following esters from most reactive to least reactive in the first slow step of a nucleophilic acyl substitution reaction (formation of the tetrahedral intermediate):