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The first compound is said to be hydrolyzed more easily than the 2nd compound below under Alkaline medium . How is this possible ?

I thought due to resonance, -NO2 acquires negative charge which faces repulsion from the solvation effect by basic medium. But it will be relatively easier for oxygen in -CH3O( in 2nd compound) to donate its electrons to have it in resonance with benzene. But this contradicts with answer. Where am I going wrong?


Going by the mechanism of hydrolysis under basic medium, the lone pair of hydroxide ion will attack on C=O carbon.

Due to the negative mesomeric (-M/-R) effect and negative inductive effect of the nitro group, the C=O will act as a more electrophilic substrate as compared to the one which is has ether substituent,

(which due to its +M and +I effect will reduce the electrophilic character of the C=O ),
will be easier to hydrolyse.

The effect of solvation on substituents is less likely to tell which compound will hydrolyse easily as it is not the Rate Determining Step of the reaction. So although the observation is not wrong, its still not the deciding factor.

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    $\begingroup$ Moreover, since the molecule is completely conjugated(in fact cross conjugated), so only a partial negative charge would exist on the nitro group in the resonance hybrid, so it's hydration will be quite less to consider $\endgroup$ – YUSUF HASAN Jan 8 at 14:17
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    $\begingroup$ Perhaps in alkaline water, the attack on the carbonyl carbon would be by OH- ion. $\endgroup$ – James Gaidis Jan 8 at 16:57
  • $\begingroup$ Done the edit,thanks! $\endgroup$ – Sidharth Giri Jan 10 at 13:28

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