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
2
views
Ch. 21 - Carboxylic Acid Derivatives
Wade9th EditionOrganic ChemistryISBN: 9780135213728
Not the one you use?Change textbookSelect a different textbook
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 38a
Show how you would convert the following starting materials to the indicated nitriles:
(a) phenylacetic acid → phenylacetonitrile
Verified step by step guidance1
Identify the functional group in the starting material, phenylacetic acid. It contains a carboxylic acid group (-COOH) attached to a benzyl group (C6H5-CH2-). The goal is to replace the carboxylic acid group with a nitrile group (-CN).
Recall that carboxylic acids can be converted to nitriles through a two-step process: (1) conversion of the carboxylic acid to an amide intermediate, and (2) dehydration of the amide to form the nitrile.
In the first step, react phenylacetic acid with a reagent like thionyl chloride (SOCl2) to convert the carboxylic acid into an acid chloride (phenylacetyl chloride). This step activates the carboxylic acid for further reaction.
In the second step, react the acid chloride with ammonia (NH3) to form the corresponding amide, phenylacetamide. This occurs via nucleophilic substitution, where ammonia attacks the carbonyl carbon of the acid chloride.
Finally, dehydrate the amide using a dehydrating agent such as phosphorus pentoxide (P2O5) or thionyl chloride (SOCl2) to form phenylacetonitrile. This step removes water from the amide, resulting in the nitrile group (-CN).
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nitrile Synthesis
Nitriles are organic compounds containing a cyano group (-C≡N). One common method to synthesize nitriles is through the conversion of carboxylic acids or their derivatives. In this case, phenylacetic acid can be converted to phenylacetonitrile via a dehydration reaction, often using reagents like thionyl chloride or phosphorus pentoxide to facilitate the transformation.
Recommended video:
0:59
Review of Nitriles Concept 1
Carboxylic Acid Derivatives
Carboxylic acids can be transformed into various derivatives, such as acid chlorides, esters, and amides, which can further react to form nitriles. Understanding these derivatives is crucial for predicting reaction pathways. For phenylacetic acid, converting it to an acid chloride is a key step before further reaction to yield the desired nitrile.
Recommended video:
Guided course
03:50Intro to Carboxylic Acid Derivatives
Reagents and Reaction Conditions
The choice of reagents and reaction conditions is vital in organic synthesis. For the conversion of phenylacetic acid to phenylacetonitrile, reagents like thionyl chloride (SOCl2) or phosphorus oxychloride (POCl3) are commonly used to create the acid chloride intermediate. The subsequent reaction with a suitable nucleophile, such as sodium cyanide, leads to the formation of the nitrile.
Recommended video:
Guided course
01:52Reagents
Related Practice
Textbook Question
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
1
views
Textbook Question
Show how you would convert the following starting materials to the indicated nitriles:
(b) phenylacetic acid → 3-phenylpropionitrile
2
views
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
2
views
Textbook Question
Show how each transformation may be accomplished by using a nitrile as an intermediate. You may use any necessary reagents.
(a) hexan-1-ol → heptan-1-amine
1
views
Textbook Question
Show how you would convert the following starting materials to the indicated nitriles:
(c) p-chloronitrobenzene → p-chlorobenzonitrile
2
views