Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

Organic Chemistry

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

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1:04 minutes

Problem 34d

Textbook Question

Suggest the most appropriate reagent for each synthesis, and explain your choice.
(d)

Verified step by step guidance

Step 1: Analyze the transformation. The starting material is an ethyl ester (C=O bonded to OEt), and the product is an amide (C=O bonded to NPh). This indicates that the ester group is being converted into an amide group.

Step 2: Identify the type of reaction. The conversion of an ester to an amide typically involves nucleophilic substitution, where the ethoxy group (-OEt) is replaced by an amine group (-NPh).

Step 3: Choose the appropriate reagent. To achieve this transformation, a primary amine (such as aniline, PhNH2) can be used as the nucleophile. Aniline will attack the carbonyl carbon of the ester, leading to the substitution of the ethoxy group.

Step 4: Consider reaction conditions. The reaction may require heating to facilitate the nucleophilic attack and subsequent elimination of ethanol. A solvent like toluene or THF can be used to dissolve the reactants.

Step 5: Explain the choice of reagent. Aniline (PhNH2) is chosen because it provides the phenyl group (-Ph) attached to the nitrogen in the amide product. This matches the structure of the desired product.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleophilic Acyl Substitution

Nucleophilic acyl substitution is a fundamental reaction in organic chemistry where a nucleophile attacks the carbonyl carbon of an acyl compound, leading to the replacement of a leaving group. In this case, the ester is converted to an amide by the nucleophilic attack of an amine on the carbonyl carbon, resulting in the formation of a new C-N bond and the release of the ethoxy group as a leaving group.

Reactivity of Esters

Esters are relatively reactive compounds due to the presence of the carbonyl group, which is electrophilic and susceptible to nucleophilic attack. The leaving group in esters, such as an alkoxy group, can be displaced by stronger nucleophiles, making them suitable substrates for nucleophilic acyl substitution reactions. Understanding the reactivity of esters is crucial for selecting appropriate reagents for synthesis.

Choice of Nucleophile

The choice of nucleophile is critical in nucleophilic acyl substitution reactions. In this case, an amine (NHPh) is chosen to convert the ester to an amide. Amines are good nucleophiles due to the presence of a lone pair of electrons on the nitrogen atom, which allows them to effectively attack the electrophilic carbonyl carbon, facilitating the desired transformation.

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Textbook Question

In each part, rank the compounds in order of increasing rate of nucleophilic attack at C=O by a strong nucleophile like methoxide.

(b)

Textbook Question

Suggest the most appropriate reagent for each synthesis, and explain your choice.

(a)

Textbook Question

There 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.

Textbook Question

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.

Textbook Question

Predict the products of the following reactions.

(d) anisole + succinic anhydride and aluminum chloride

Textbook Question

Show how you would accomplish the following multistep syntheses. You may use any additional reagents and solvents you need.

(e)

Textbook Question

Write the mechanism for each of the following reactions:

a. the reaction of acetyl chloride with water to form acetic acid

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