[Altered State]

This is what I want to do:



I know that I can transform CH3 group to COOH oxidating with KMnO4, but if I do that on the first place, I'm getting a very deactivated ring, so I won't be able to add Br.

So I think I need to add Br on the first place, but I don't see how. If I directly use Br2/FeBr3, bromination will go in the ortho left position and in para position.
I know that if I add SO3/H2SO4, I can protect para position, and then add Br to ortho, but I do not need that, I need to add Br in para of methyl. How could I do that?

[antimatter101]

This is the only thing I figured out.

Try and add bromine first.

[Altered State]

This is the only thing I figured out.

Try and add bromine first.

I've been looking for info about this kind of reations for about 5 hours today and I realized that in most cases, solving these kind of exercises you won't get just one product, but you should find out the best way to obtain it, am I right?

If I do what you say (that's what I thought), I add bromine first, and I would get product with Br in the Ortho and Para possition (mostly para, ortho has kind of steric impediments), then I oxide with KMnO4 and I get mostly (but not only it) the final product.
Is it this?

[orgopete]

I would also expect an o/p mixture, but it could be carried to the desired product.

[Altered State]

I would also expect an o/p mixture, but it could be carried to the desired product.

That's the key???
I think that's not material of my course, but HOW??

[orgopete]

How?
Separating the mixture?

[Altered State]

How?
Separating the mixture?

Oh, I thought you were refering to any special reaction conditions so it would give just the desired produt, but that will do...
I'm totally new on organic chemistry, and it is not in my mind that most of the times we won't get just our product and we need to separate later.

[orgopete]

You may find that many reactions give mixtures of ortho and para products. These are often intensively researched in search of conditions to improve the selectivity. The success can vary. In the end, it would not be unusual that a separation is required to isolate a single product. As far as I know, there is no simple model that can be used to predict which structure should be the major product