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Acid-catalyzed hydrolysis of a nitrile to give a
a)
Interpretation:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step, is to be given.
Concept introduction:
The acid protonates the nitrogen of the nitrile group initially. The nucleophilic attack by water and subsequent proton transfer will yield an intermediate. Another nucleophilic attack by water on the intermediate and yet another proton transfer produces another intermediate. The intermediate loses ammonia to produce the protonated acid which deprotonates to yield the acid.
To give:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step.
Answer to Problem 25MP
The products of the reaction are ammonia and 2,2-dimethylbutanoic acid.
The mechanism of the reaction is given below.
Explanation of Solution
In the first step, 2,2-dimethylbutane nitrile is protonated by HCl. In the next step, the nucleophilic attack of water on the protonated nitrile occurs and the accompanying proton transfer yields a protonated aminoketone. Another nucleophilic attack on the carbonyl carbon of the protonated aminoketone in the next step and the subsequent proton transfer yields a protonated diol intermediate which eliminates ammonia and a proton in the subsequent steps to yield 2,2-dimethylbutanoic acid.
The products of the reaction are ammonia and 2,2-dimethylbutanoic acid.
The mechanism of the reaction is given below.
b)
Interpretation:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step, is to be given.
Concept introduction:
The acid protonates the nitrogen of the nitrile group initially. The nucleophilic attack by water and subsequent proton transfer will yield an intermediate. Another nucleophilic attack by water on the intermediate and yet another proton transfer produces another intermediate. The intermediate loses ammonia to produce the protonated acid which deprotonates to yield the acid.
To give:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step.
Answer to Problem 25MP
The products of the reaction are ammonia and p-methylbenzoic acid.
The mechanism of the reaction is given below.
Explanation of Solution
In the first step, p-methylbenzonitrile is protonated by HCl. In the next step, the nucleophilic attack of water on the protonated nitrile occurs and the accompanying proton transfer yields a protonated aminoketone. Another nucleophilic attack on the carbonyl carbon of the protonated aminoketone in the next step and the subsequent proton transfer yields a protonated diol intermediate which eliminates ammonia and a proton in the subsequent steps to yield p-methylbenzoic acid.
The products of the reaction are ammonia and p-methylbenzoic acid.
The mechanism of the reaction is given below.
c)
Interpretation:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step, is to be given.
Concept introduction:
The acid protonates the nitrogen of the nitrile group initially. The nucleophilic attack by water and subsequent proton transfer will yield an intermediate. Another nucleophilic attack by water on the intermediate and yet another proton transfer produces another intermediate. The intermediate loses ammonia to produce the protonated acid which deprotonates to yield the acid.
To give:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step.
Answer to Problem 25MP
The products of the reaction are ammonia and 2-methylbutanoic acid.
The mechanism of the reaction is given below.
Explanation of Solution
In the first step, 2-methylbutane nitrile is protonated by HCl. In the next step, the nucleophilic attack of water on the protonated nitrile occurs and the accompanying proton transfer yields a protonated aminoketone. Another nucleophilic attack on the carbonyl carbon of the protonated aminoketone in the next step and the subsequent proton transfer yields a protonated diol intermediate which eliminates ammonia and a proton in the subsequent steps to yield 2-methylbutanoic acid.
The products of the reaction are ammonia and 2-methylbutanoic acid.
The mechanism of the reaction is given below.
d)
Interpretation:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step, is to be given.
Concept introduction:
The acid protonates the nitrogen of the nitrile group initially. The nucleophilic attack by water and subsequent proton transfer will yield an intermediate. Another nucleophilic attack by water on the intermediate and yet another proton transfer produces another intermediate. The intermediate loses ammonia to produce the protonated acid which deprotonates to yield the acid.
To give:
The products of the reaction, the acid-catalyzed nitrile hydrolysis, along with all the steps involved using curved arrows to represent electron flow in each step.
Answer to Problem 25MP
The products of the reaction are ammonia and cyclopentanecarboxylic acid.
The mechanism of the reaction is given below.
Explanation of Solution
In the first step, cyclopentanenitrile is protonated by HCl. In the next step, the nucleophilic attack of water on the protonated nitrile occurs and the accompanying proton transfer yields a protonated aminoketone. Another nucleophilic attack on the carbonyl carbon of the protonated ketone in the next step and the subsequent proton transfer yields a protonated aminodiol intermediate which eliminates ammonia and a proton in the subsequent steps to yield cyclopentanecarboxylic acid.
The products of the reaction are ammonia and cyclopentanecarboxylic acid.
The mechanism of the reaction is given below.
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Chapter 20 Solutions
Bundle: Organic Chemistry, Loose-leaf Version, 9th + LMS Integrated for OWLv2, 4 terms (24 months) Printed Access Card
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