Sciencemadness Discussion Board - Diphenylamine via Friedels-Craft-Alkylation?

Diphenylamine via Friedels-Craft-Alkylation?

Amoled - 3-9-2018 at 09:09

Good Evening,

Is it possible to add a phenyl-group to an amine?
In this case its about reacting anilline with chlorobenze, to produce Diphenylamine, if necessary with a catalyst (probably needed), like AlCl₃

[Edited on 3-9-2018 by Amoled]

Sigmatropic - 3-9-2018 at 10:23

The thing you are looking for is called the Buchwald-Hartwig amination. AlCl3 is not a catalyst for said reaction. Copper, in the Ulmann reaction can do the same. both of these reactions require fine tuning the ligand, base and solvent to obtain good yields. Low yields are much more easily achievable.

Amoled - 3-9-2018 at 11:03

Thank you, I will dig into it a little bit deeper, the Buchwald-Hartwig Coupling especially, looks like something I need.
But it looks like you need some complex catalysators for this reaction.
Or better said the Ligands are hard to get for an Amateur chemist

[Edited on 3-9-2018 by Amoled]

Sigmatropic - 3-9-2018 at 11:26

A variation of the Ulmann reaction is described on prepchem. http://www.prepchem.com/synthesis-of-diphenylamine/

Swinfi2 - 3-9-2018 at 17:36

Yeah unfortunately this one doesn't work with the easy method as the product 2° amine is more easily alkylated than the 1°.

I suppose a large excess of the 1° amine and extremely slow/dilute addition -might- work but it's a gamble.

wildfyr - 4-9-2018 at 04:59

This is a tough one for an amateur chemist. Buchwald-Hartwig amination is the most straightforward, but yeah, it needs Pd and catalysts.

You could try to deprotonate aniline with BuLi, LDA, or NaH, and heat the christ out of it (under pressure) but that isn't very safe or dependable.

Sigmatropic's Ullman reaction is by far the best option.

zed - 4-9-2018 at 15:52

Chlorobenzene is not very reactive. I wouldn't expect it to work very well.

Maybe Bromobenzene. http://www.prepchem.com/synthesis-of-diphenylamine/

CuReUS - 5-9-2018 at 04:39

Quote: Originally posted by wildfyr

You could try to deprotonate aniline with BuLi

You are partly right - https://pubs.acs.org/doi/10.1021/ol302688u

Amoled - 5-9-2018 at 04:41

Quote: Originally posted by zed

Chlorobenzene is not very reactive. I wouldn't expect it to work very well.

Maybe Bromobenzene. http://www.prepchem.com/synthesis-of-diphenylamine/

Yeah, this was just a probably bad example, just wanna know if there is a Good way, to benzylate amines - not necessary an amine with a benzene Ring on it.

Sigmatropic - 5-9-2018 at 09:11

Benzylation is different from phenylation (and arylation). With the right nomenclature you're much more likely to find relevant literature. I suggest using reaxys or scifinder and grouping the reactions into say strong base catalyzed processes or palladium catalyzed, nickel catalyzed, copper catalyzed ect.