0
$\begingroup$

I was asked to find out the major product formed when this molecule is subjected to nitration using $\ce{HNO3/H2SO4}$ mixture

enter image description here

Here $\ce{NO2+}$ will be the electrophile. Lets call the benzene ring which is directly attached to the carbonyl group as ring 1 (benzylic ring) and the other as ring 2 (phenolic ring). Now ring 2 is attached to an activating group as $\ce O$ will show +M and will increase the relative electron density at o-p positions. But the electrophile will preferably attack para position due to steric hindrance at ortho position.

Benzene ring 1 is attached to a carbon atom which in turn is connected to a more electronegative atom. So it is partially positively charged and will show -M effect thereby deactivating the ring. But it is also meta directing group. So will the electrophile attack meta position of ring 1?

The answer to this question says, ring 1 won't be attacked by the electrophile as it is attached to a deactivating group. The the molecule after nitration is

enter image description here

Then how to identify whether an electrophile will attack benzene ring when a deactivating group is attached to it?

$\endgroup$
  • $\begingroup$ It's not a matter of if, but of on what time scale will the reaction proceed. minutes, hours, geological eras. $\endgroup$ – A.K. Oct 8 '18 at 15:36
  • $\begingroup$ I agree that the phenolic ring reacts first, but if it stops there depends on the conditions because it is possible to nitrate benzene rings with deactivating groups, after all dinitrobenzene is fairly easy to make docsity.com/en/… $\endgroup$ – Waylander Oct 8 '18 at 19:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy