[rentj]

I recently learnt about the electrophilic substitution of a nitro functional group into an aromatic compound. The book I am using says according to the picture attached.

I know it is a meta director, but the thing I am confused about why only one of the meta position is substituted with the nitro group. Why not the other meta position? I know this has to do with the symmetry of the compound itself, but I cannot any resource that explains about it.

[Babcock_Hall]

What assumptions are you making about the bond that connects the carbonyl carbon to the carbon of the aromatic ring?

[rentj]

Is it able to freely rotate? I am not quite sure since it is a pi bond.

[rolnor]

You have some conjugation, but what do you know about this type of systems? Start with looking up if the bond can rotate, freely or not so freely

[rentj]

I cannot find any resources regarding that.

[Vidya]

Look at the starting molecule and check there are two meta positions ( 3 carbon with respect to C containing the substituent).Both meta positions are chemically identical and nitration can take place on any one of them.

[Babcock_Hall]

@OP, Taking the existence of only one meta-isomer as a given, what does that imply about the rotation around the C-C bond in question?

[kalyl]

The reason why only one of the meta positions is substituted with the nitro group has to do with the steric hindrance and electronic effects of the substituents already present on the aromatic ring.

[rolnor]

The reason why only one of the meta positions is substituted with the nitro group has to do with the steric hindrance and electronic effects of the substituents already present on the aromatic ring.

Melon Playground

Yes, the dinitro is not likely to be formed, but here the question was if the two meta-positions in the starting material are the same as I understand it