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 37
Show how you would accomplish the following syntheses using amides as intermediates. You may use any necessary reagents.
(a) benzoic acid → benzyldimethylamine
(b) pyrrolidine → N-ethylpyrrolidine
(c) cyclopentanecarboxylic acid → cyclopentanecarbonitrile
Verified step by step guidance1
Step 1: For part (a), begin by converting benzoic acid to benzoyl chloride. This can be achieved using a reagent like thionyl chloride (SOCl₂) or phosphorus pentachloride (PCl₅). The reaction replaces the hydroxyl group (-OH) of the carboxylic acid with a chlorine atom, forming benzoyl chloride.
Step 2: React benzoyl chloride with dimethylamine (H₂NCH₃₂) to form the corresponding amide, N,N-dimethylbenzamide. This reaction typically occurs via nucleophilic acyl substitution, where the amine attacks the carbonyl carbon of the acyl chloride.
Step 3: Reduce the amide (N,N-dimethylbenzamide) to benzyldimethylamine using a reducing agent such as lithium aluminum hydride (LiAlH₄). The reduction converts the amide functional group into an amine, completing the synthesis for part (a).
Step 4: For part (b), start by reacting pyrrolidine with ethyl chloroformate (ClCOOCH₂CH₃) to form an N-ethylcarbamate intermediate. This step introduces the ethyl group onto the nitrogen atom of pyrrolidine.
Step 5: Hydrolyze the carbamate intermediate under acidic or basic conditions to yield N-ethylpyrrolidine. This step removes the carbamate group, leaving the desired ethyl-substituted pyrrolidine.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Amides as Intermediates
Amides are organic compounds derived from carboxylic acids and amines, characterized by the functional group -C(=O)N-. They serve as versatile intermediates in organic synthesis, allowing for the transformation of carboxylic acids into amines or other nitrogen-containing compounds through various reactions, such as reduction or alkylation.
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Amide Nomenclature
Nucleophilic Substitution Reactions
Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule with a nucleophile. In the context of amides, this can include the alkylation of amides to form substituted amines. Understanding the mechanisms of these reactions is crucial for predicting the products of the syntheses outlined in the question.
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01:47Nucleophiles and Electrophiles can react in Substitution Reactions.
Carboxylic Acid Derivatives
Carboxylic acid derivatives, such as esters, amides, and anhydrides, are compounds that can be derived from carboxylic acids by replacing the hydroxyl group (-OH) with another functional group. Recognizing how these derivatives can be interconverted is essential for the synthesis of target compounds, as they often dictate the reactivity and pathways available in organic reactions.
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Related Practice
Textbook Question
Show how you would convert the following starting materials to the indicated nitriles:
(b) phenylacetic acid → 3-phenylpropionitrile
670
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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
769
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Textbook Question
Show how you would convert the following starting materials to the indicated nitriles:
(a) phenylacetic acid → phenylacetonitrile
890
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Textbook Question
Show how you would accomplish the following synthetic transformations. You may use any necessary reagents.
(c) pyrrolidine → N-acetylpyrrolidine
(d) γ-aminobutyric acid → pyrrolidine
1011
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Textbook Question
Show how you would convert the following starting materials to the indicated nitriles:
(c) p-chloronitrobenzene → p-chlorobenzonitrile
555
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