Textbook Question
Show how you would accomplish the following synthetic transformations. You may use any necessary reagents.
(a) N-ethylbenzamide → benzylethylamine
(b) ethyl benzoate → N-ethylbenzamide
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Ch. 21 - Carboxylic Acid Derivatives
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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Table of contents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
Chapter 21, Problem 35a,b,c
Show how you would synthesize each compound, starting with an ester containing no more than eight carbon atoms. Any other necessary reagents may be used.
(a) Ph3C–OH
(b) (PhCH2)2CHOH
(c) PhCONHCH2CH3
Verified step by step guidance1
Step 1: For compound (a) Ph3C-OH, start with an ester containing no more than eight carbons, such as ethyl benzoate (C6H5COOCH2CH3). Perform a Grignard reaction by reacting ethyl benzoate with phenylmagnesium bromide (PhMgBr) to form the triphenylmethanol (Ph3C-OH). This involves the addition of the Grignard reagent to the ester, followed by hydrolysis.
Step 2: For compound (b) (PhCH2)2CHOH, begin with an ester like ethyl benzoate (C6H5COOCH2CH3). React ethyl benzoate with benzylmagnesium bromide (PhCH2MgBr) in excess to form the desired alcohol. The Grignard reagent adds twice to the ester, followed by hydrolysis to yield the secondary alcohol.
Step 3: For compound (c) PhCONHCH2CH3, start with ethyl benzoate (C6H5COOCH2CH3). Perform a reaction to convert the ester into a benzamide (PhCONH2) by reacting it with ammonia (NH3). Then, perform an alkylation reaction using ethyl iodide (CH3CH2I) to introduce the ethyl group on the nitrogen, forming PhCONHCH2CH3.
Step 4: Ensure that the reaction conditions for each step are carefully controlled. For Grignard reactions, use anhydrous conditions to prevent side reactions. For the amide formation, use a suitable base or catalyst to facilitate the reaction.
Step 5: Verify the structures of the synthesized compounds using spectroscopic techniques such as NMR and IR to confirm the presence of the functional groups and the overall molecular structure.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ester Synthesis
Ester synthesis involves the reaction of an alcohol with a carboxylic acid or an acid derivative, typically through a condensation reaction that releases water. This process is fundamental in organic chemistry as it forms the backbone for creating various compounds, including the target compounds in the question. Understanding the reactivity of esters and their derivatives is crucial for planning synthetic routes.
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Grignard Reagents
Grignard reagents are organomagnesium compounds that are highly reactive and can be used to form carbon-carbon bonds. They are generated by reacting magnesium with an alkyl or aryl halide. In the context of the question, Grignard reagents can be employed to synthesize alcohols from esters, making them essential for constructing the specified compounds.
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Nucleophilic Addition
Nucleophilic addition is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks an electrophilic carbon atom, leading to the formation of new bonds. This concept is particularly relevant for the synthesis of the target compounds, as it explains how various reagents can add to carbonyl groups in esters and ketones, facilitating the transformation into alcohols and amines.
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Related Practice
Textbook Question
Suggest the most appropriate reagent for each synthesis, and explain your choice.
(c)
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Textbook Question
Suggest the most appropriate reagent for each synthesis, and explain your choice.
(b)
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Textbook Question
Show how you would synthesize each compound, starting with an ester containing no more than eight carbon atoms. Any other necessary reagents may be used.
(d) Ph2CHOH
(e) PhCH2OH
(f) PhCOOH
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Textbook Question
Show how you would synthesize each compound, starting with an ester containing no more than eight carbon atoms. Any other necessary reagents may be used.
(i) HO–(CH2)8–OH
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Textbook Question
Suggest the most appropriate reagent for each synthesis, and explain your choice.
(d)
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