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

Saponification

Organic Chemistry

22. Carboxylic Acid Derivatives: NAS

Saponification

Previous problemNext problem

5:52 minutes

Problem 68i,j

Textbook Question

What are the products of the following reactions?
i.
j.

Verified step by step guidance

Step 1: Analyze the reaction in part (i). The starting material is an ester (methyl benzoate), and the reagent is excess ammonia (NH₃). Ammonia reacts with esters in a nucleophilic acyl substitution reaction, where the ammonia attacks the carbonyl carbon of the ester.

Step 2: In part (i), the nucleophilic attack by ammonia leads to the formation of an intermediate tetrahedral structure. The methoxy group (-OCH₃) is displaced, resulting in the formation of a primary amide (benzamide). The excess ammonia ensures complete conversion to the amide.

Step 3: Analyze the reaction in part (ii). The starting material is a cyclic ester (lactone), and the reagent is NaOH followed by acid workup. NaOH hydrolyzes the lactone via nucleophilic attack on the carbonyl carbon, breaking the ring and forming a carboxylate intermediate.

Step 4: In part (ii), after hydrolysis by NaOH, the acid workup protonates the carboxylate group, resulting in the formation of a linear carboxylic acid. The hydroxyl group from the lactone remains intact, forming a hydroxy acid.

Step 5: Summarize the products: (i) The product is benzamide (C₆H₅CONH₂). (ii) The product is a hydroxy acid derived from the lactone, specifically 6-hydroxyhexanoic acid.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Carboxylic Acid Derivatives

Carboxylic acid derivatives, such as esters, amides, and anhydrides, are compounds that can be derived from carboxylic acids. They retain the carboxyl functional group but have different substituents. Understanding their reactivity is crucial, as they can undergo nucleophilic acyl substitution reactions, where a nucleophile replaces the leaving group, leading to the formation of new products.

Nucleophilic Acyl Substitution

Nucleophilic acyl substitution is a fundamental reaction in organic chemistry where a nucleophile attacks the electrophilic carbon of a carbonyl group in a carboxylic acid derivative. This reaction typically involves the formation of a tetrahedral intermediate, followed by the elimination of a leaving group. In the context of the question, excess NH3 acts as the nucleophile, leading to the formation of an amide.

Acid-Base Reactions and Workup Procedures

In organic synthesis, acid-base reactions are often used to neutralize reaction mixtures or to facilitate the isolation of products. The term 'acid workup' refers to the process of adding acid to a basic reaction mixture to protonate and precipitate the desired product. In the second reaction, the use of NaOH followed by acid workup indicates that a carboxylic acid is likely formed from the reaction, which can then be isolated.

Watch next

Master Mechanism with a bite sized video explanation from Johnny

Start learning