Deck 21: The Chemistry of Carboxylic Acid Derivatives

Question 1

Draw a structure for these carboxylic acid derivatives.
a. propyl 4-ethylbenzoate
b. N-ethyl-N-methylpentanamide
c. cyclohexanecarbonyl chloride

Answer 1

a. The -oate suffix indicates an ester. The first part of the name of an ester refers to the alkyl group connected to the oxygen in the ester. A benzoate is a benzene ring with an ester substituent. Lastly, the 4-ethyl indicates an ethyl group para to the ester functionality. The structure of propyl 4-ethyl benzoate is:
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b. The name indicates a five-carbon chain where the amide is on carbon 1 and the nitrogen has an ethyl and methyl substituent.
c. The compound is an acid chloride which is bonded to a cyclohexane ring.

Question 2

Rank the priority of principal groups in nomenclature.

A) anhydride > acid > ester > amide
B) amide > acid > anhydride > ester
C) acid > anhydride > ester > amide
D) ester > acid > amide > anhydride

Answer 2

C

Question 3

Draw the major organic product of the reaction. If you believe no reaction would occur, write NR.

Answer 3

The azide ion will react with the acid chloride to form an acyl azide.

Question 4

Provide a detailed, arrow-pushing mechanism for the transformation. Show all reactive intermediates and all proton transfer steps. (It is not necessary to show every resonance structure for intermediates.)

Question 5

The Ritter reaction is a useful method for producing substituted amides. Provide a detailed, arrow-pushing mechanism for the transformation. Show all reactive intermediates and all proton transfer steps. (It is not necessary to show every resonance structure for intermediates.)

Question 6

Choose the best reagent(s) for carrying out the conversion.

A) Mg, ether; CO₂; then aqueous acid
B) NaCN; then aqueous acid
C) Both sets of reagents would work equally well.
D) Neither set of reagents would work well.

Question 7

Describe the equilibrium constant for the reaction.

A) K > 1
B) K < 1
C) K = 1
D) can't determine K without knowing heats of formation

Question 8

Propose a synthesis of the transformation.

Question 9

Which reagents could be used to synthesize PhCOOH?

A) PhCO₂CH₃ in acidic methanol
B) PhCOCl + LiAlH₄ followed by treatment with acid
C) PhCO₂CH₃ in aqueous base followed by treatment with acid
D) More than one of these would work.
E) None of these would work.

Question 10

Predict the major organic product of the reaction. If you believe no reaction would occur, write NR.

Question 11

Predict the major organic product of the reaction. If you believe no reaction would occur, write NR.

Question 12

a. Provide arrow-pushing mechanisms for the reaction. Clearly show all intermediates.
b. If you wanted to reverse the transformation, what reagent(s) would you use? No reaction mechanism is necessary.

Question 13

Which of the compounds would be the least acidic?

A) compound A
B) compound B
C) compound C
D) compound D
E) compound E

Question 14

When these two amides undergo hydrolysis under identical reaction conditions, it is found that amide A reacts significantly faster (>1000 times) than does amide B.
a. Draw the structure of each hydrolysis product in the appropriate box.
b. Using concepts developed in this course, and using structures and reaction coordinate diagrams, explain the above indicated difference in the hydrolysis rates. (Assume the ring strains in amides A and B are essentially equal, and the tetrahedral intermediates (TIs) for both reactions are of about equal energy.)

Question 15

Predict the major organic product of the reaction. If you believe no reaction would occur, write NR.

Question 16

Predict the major organic product of the reaction. If you believe no reaction would occur, write NR.

Question 17

Predict the major organic product of the reaction. If you believe no reaction would occur, write NR.

Question 18

Outline a synthesis for the transformation using the indicated starting material and any other organic reagent containing two carbons or less. You may also use any inorganic reagents and solvents you might need. Show the structures of all intermediate compounds. Reaction mechanisms are not necessary.

Question 19

When the mixed carbonate below is treated with an excess of ethyl magnesium bromide, the indicated tertiary alcohol is formed in high yield. Write a detailed reaction mechanism for the first step of the reaction. Label "end of step 1" at the appropriate location. Indicate all organic products including by-products at the end of step 2.

Question 20

Given the synthetic sequence, predict the structures of the intermediate A and product B.

Question 21

A student is asked to monitor the reaction by infrared spectroscopy. Explain what peaks the student should use to monitor the reaction (appearance and disappearance).

Question 22

An unlabeled flask contains a compound with a molecule mass of 86. The ¹H NMR data are  2.10 (pentet, J = 7.1, 2H), 2.30 (t, J = 7.1, 2H), and 4.30 (t, J = 7.1, 2H). The ¹³C NMR data are  22.5, 27.9, 68.8, and 178.1. The compound gives a positive hydroxamate test. Deduce the structure of the unknown compound.

Question 23

Outline a synthesis for the transformation.

Question 24

Outline a synthesis for the transformation.

Question 25

Draw a triglyceride formed from glycerol and three molecules of stearic acid (CH₃(CH₂)₁₆COOH).