Organic Chemistry Basics - Result Question 135
####3. Which of the following compounds will show the maximum ’enol’ content?
(2019 Main, 8 April II)
(a) $CH _3 COCH _3$
(b) $CH _3 COCH _2 COCH _3$
(c) $CH _3 COCH _2 COOC _2 H _5$
(d) $CH _3 COCH _2 CONH _2$
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Answer:
Correct Answer: 3. (d)
Solution:
This enol-form is highly stable because of intramolecular H-bonding (6-membered stability) and due to extended conjugation.
In both of the compounds, $C-2$ of $C=O$ group is a part of the acid derivative (ester, $-\stackrel{C}{C}-OEt$ and acid amide, $\stackrel{|}{C}-NH _2$ ). So, $>C^{2}=0$ does not take part in enolisation, because it is already in resonance $(-R)$ with the derivative group itself.
