Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions

21-48 Predict the product, if any, of the reaction between propanoyl chloride and the following reagents:

1. $\mathrm{Li}\left(\mathrm{Ph}\right)\mathrm{Cu} \mathrm{in} et\mathrm{her}$
2.   $\mathit{L}\mathit{i}\mathit{A}\mathit{l}{\mathit{H}}_4,\mathit{ }\mathit{t}\mathit{h}\mathit{e}\mathit{n}\mathit{ }{\mathit{H}}_3{\mathit{O}}^{+}$
3.   $\mathit{C}{\mathit{H}}_3\mathit{M}\mathit{g}\mathit{B}\mathit{r},\mathit{ }\mathit{t}\mathit{h}\mathit{e}\mathit{n}\mathit{ }{\mathit{H}}_3{\mathit{O}}^{+}$
4.  ${\mathit{H}}_3{\mathit{O}}^{+}$
5. Cyclohexanol
6. Aniline
7. $\mathit{C}{\mathit{H}}_3\mathit{C}{\mathit{O}}_2^{-}\mathit{N}{\mathit{a}}^{+}$

21-49 Answer Problem 21-48 for reaction of the listed reagents with methyl propanoate.

21-50 Answer Problem 21-48 for the reaction of the listed reagents with propanamide

21-51 What product would you expect to obtain from Grignard reaction of an excess of phenylmagnesium bromide with dimethyl carbonate, $C{H}_{3}OC{O}_{2}C{H}_3$ ?

21-52 How might you prepare the following compounds from butanoic acid?

1. 1-Butanol
2. Butanal
3. 1-Bromobutane
4. Pentanenitrile
5. 1-Butene
6. 2-Hexanone

Predict the product(s) of the following reactions:

The Following reactivity order has been found for the saponification of alkyl acetates by aqueous NaOH Explain.

  $C{H}_{3}C{O}_{2}C{H}_3>C{H}_{3}C{O}_{2}C{H}_{2}C{H}_3>C{H}_{3}C{O}_{2}CH{\left(C{H}_3\right)}_2>C{H}_{3}C{O}_{2}CH{\left(C{H}_3\right)}_3$      

Explain the observation that attempted Fischer esterification of 2,4,6-trimethyl benzoic acid with methanol and HCL is unsuccessful. No ester is obtained, and the acid is recovered unchanged. What alternative method of esterification might be successful?

Treatment of 5- aminopentanoic acid DCC(dicyclohexylcarbodiimide) yields a lactam. Show the structure of the product and the mechanism of the reaction.

Outline methods for the preparation of acetophone(Phenyl methyl ketone) starting from the following:

d)  Benzonitrile e) Styrene

When ethyl benzoate is heated in methanol containing a small amount of HCL, Methyl benzoate is formed. Propose a mechanism for the reaction.

Butoxyycarbony azide, a reagent used in protein synthesis, is prepared by treating tert-butoxy carbonyl chloride with sodium azide. propose a pose mechanism for this reaction

The step-growth polymer nylon 6 is prepared from caprolactam. The reaction involves the initial reaction of caprolactam with water to give an intermediate open-chain amino acid, followed by heating to form the polymer. Propose a mechanism for both steps, and show the structures of nylon 6.

21-61 Qiana, a polyamide fiber with a silky texture, has the following structure. What are the monomer units used in the synthesis of Qiana?

Question: 21-63 Polyimides with the structure shown are used as coatings on glass and plastics to improve scratch resistance. How would you synthesize a polyimide? (See Problem 21-39.)

21-68 When a carboxylic acid is dissolved in isotopically labeled water, thelabel rapidly becomes incorporated into both oxygen atoms of the carboxylic acid. Explain.
 $\text{R}-\stackrel{\text{O}}{\stackrel{\parallel }{\text{C}}}-\text{OH }\stackrel{{\text{H}}_{\text{2}}\text{O}}{\to }\text{ R}-\stackrel{\text{O}}{\stackrel{\parallel }{\text{C}}}-\text{OH}$

21-69 We said in Section 21-6 that mechanistic studies on ester hydrolysishave been carried out using ethyl propanoate labeled with in theether-like oxygen. Assume that${}^{\mathbf{\text{18}}}\mathbf{\text{O}}\mathbf{-}$ labeled acetic acid is your onlysource of isotopic oxygen, and then propose a synthesis of the labeledethyl propanoate.

21-70 Treatment of a carboxylic acid with trifluoroacetic anhydride leads to anunsymmetrical anhydride that rapidly reacts with alcohol to give an ester.
  $\mathbf{\text{R}}\mathbf{-}\stackrel{\mathbf{\text{O}}}{\stackrel{\mathbf{\parallel }}{\mathbf{\text{C}}}}\mathbf{-}\mathbf{\text{OH }}\stackrel{{\mathbf{\left(}{\mathbf{\text{CF}}}_{\mathbf{\text{3}}}\mathbf{\text{CO}}\mathbf{\right)}}_{\mathbf{\text{2}}}\mathbf{\text{O}}}{\mathbf{\to }}\mathbf{\text{ R}}\mathbf{-}\stackrel{\mathbf{\text{O}}}{\stackrel{\mathbf{\parallel }}{\mathbf{\text{C}}}}\mathbf{-}\mathbf{\text{O}}\mathbf{-}\stackrel{\mathbf{\text{O}}}{\stackrel{\mathbf{\parallel }}{\mathbf{\text{C}}}}\mathbf{-}{\mathbf{\text{CF}}}_{\mathbf{\text{3}}}\stackrel{{\mathbf{\text{R}}}^{\mathbf{\text{'}}}\mathbf{\text{OH}}}{\mathbf{\to }}\mathbf{\text{ R}}\mathbf{-}\stackrel{\mathbf{\text{O}}}{\stackrel{\mathbf{\parallel }}{\mathbf{\text{C}}}}\mathbf{-}{\mathbf{\text{OR}}}^{\mathbf{\text{'}}}\mathbf{+}{\mathbf{\text{CF}}}_{\mathbf{\text{3}}}{\mathbf{\text{CO}}}_{\mathbf{\text{2}}}\mathbf{\text{H}}$
 (a) Propose a mechanism for the formation of the unsymmetrical anhydride.
 (b) Why is the unsymmetrical anhydride unusually reactive?
(c) Why does the unsymmetrical anhydride react as indicated ratherthan giving a trifluoroacetate ester plus carboxylic acid?

21-71 Butacetin is an analgesic (pain-killing) agent that is synthesized commercially from p-fluoronitrobenzene. Propose a synthesis.

Draw the structure of the polymer you would expect to obtain from
reaction of dimethyl terephthalate with a triol such as glycerol. Whatstructural feature would this new polymer have that was not present inDacron (Table 21-2)? How do you think this new feature might affectthe properties of the polymer?

Assign structures to compounds with the following ¹H NMR spectra:

(a)C₅H₁₀O₂

IR:1735 ${\mathrm{cm}}^{-1}$

(b)C₁₁H₁₂O₂

IR:1710 ${\mathrm{cm}}^{-1}$ 

Assign structures to compounds with the following ¹H NMR spectra:

(a)C₅H₉ClO₂

IR:1735 cm^-1

Propose a structure for the compound with the formulaC₁₉H₉NO₂ and the following IR and NMR spectra

Draw the structure of the compound that produced the spectra below.

The infrared spectrum has strong bands at1720 and 1738 cm^-1