Urgent Orgo Question?

Question

How can you make a tri-halogen benzene ring, such that one is F, one is I, and the other is Br, alternating?

Answer 1

This is how I would do it. Start with aniline. Protect the NH2 as the isopropyl carbamate. Next use Snieckus ortho lithiation procedure (http://www.organic-chemistry.org/namedreactions/directed-ortho-metalation.shtm)
so react that product with n-BuLi and trap the anion with N-iodosuccinimide. This will give the isopropyl protected 2-iodoaniline. Next remove the protecting group using TFA. This will give 2-iodoaniline. Take this prodict and react it with NBS. Unfortunately you will get a mixture of products the 2-bromo-5-iodoaniline and 2-bromo-4-iodoaniline at this stage and must separate them. Once you have done that do the Sandmeyer reaction to convert the NH2 to the fluoride. I hope this helps. I am sure there are a number of ways to synthesize this product but I think this would work.

Answer 2

Benzene + I2 + HNO3 ===> Iodobenzene
Iodobenzene + HNO3 + H2SO4 ===> 4-Iodonitrobenzene
4-Iodonitrobenzenebenzene + reduction ===> 4-Iodoaniline
4-Iodoaniline + acetic anhydride ===> 4-Iodoacetanilide
4-Iodoacetanilide + Br2 + FeBr3 ===> 2-Bromo-4-iodo acetanilide
2-Bromo-4-iodoacetanilide + HNO3 + H2SO4 ===> 2-Bromo-4-iodo-6-nitro acetanilide
2-Bromo-4-iodo-6-nitro acetanilide + reduction ===> 2-Amino-4-iodo-6-bromo acetanilide
2-Amino-4-iodo-6-bromo acetanilide + NaNO2 + HCl ===> 2-Acetamino-3-bromo-5-iodo benzene diazonium chloride
2-Acetamino-3-bromo-5-iodo benzene diazonium chloride + HF ===> 2-Bromo-6-fluoro-4-iodo acetanilide

Finally, hydrolyze the acetamino group to amino. Diazotize the amino with NaNO2 + HCl. Treat that diazonium salt with hypophosphorous acid, H3PO2, to remove diazonium and replace with -H. Product = 3-Bromo-5-fluoroiodobenzene.

It's a little confusing, because I have to renumber the ring to keep the substituents in alphabetical order for correct names. Also, I have to put spaces in the names that really shouldn't be there; otherwise, Yahoo Answers will cut them short.