[coolkul]

I'm having a difficult time figuring these reactions out. What positions would the bromine be substituted in and why?




Mod edit: IMG code fixed

[Alexis7]

NH2 is a very powerful activator... Probably one of the strongest. Activators are ortho-para directions. They will donate electron density to the ring.

1 eq of Br will be at one of the ortho positions to the NH2. It would go to the Para position, but the methyl is already occupying it. So it goes to ortho.

NO2 is a powerful deactivator. Deactivators are meta directors so the Br will be at the one of meta positions.

Deactivators= meta

Activators= ortho-para

Cheers

~Alexis

[mamid]

For the 1st reaction: methoxy is also a strong o/p director, and this effect goes in the same direction with the m-directing effect of the nitro group, so the bromine ends up ortho to the methoxy. When the effect of an activating group doesn't concur with that of a deactivating group, the activator prevails.

[Alexis7]

Methoxy is a moderate actiavtor compared to NO2 which is a strong deactivator.

Either way they end up in the meta position to the NO2 and Ortho to methoxy.

[Babcock_Hall]

The amine may protonate in the presence of HBr, which changes the picture.