[Messi]

Hey guys,

I am trying to find a procedure for creating dibenzylamine. I am thinking alkylating benzylamine would be the easiest way. Is there a procedure for this?

[discodermolide]

Why not just buy it?

[Messi]

Why not just buy it?

Because it will take some time, and my supervisor wants to save a little bit of money while giving me some experience with different types of chemistry

[discodermolide]

Reductively aminate benzaldehyde with sodium cyanoborohydride.
http://en.wikipedia.org/wiki/Reductive_amination

[Messi]

Reductively aminate benzaldehyde with sodium cyanoborohydride.
http://en.wikipedia.org/wiki/Reductive_amination

I am looking more for a procedure

[discodermolide]

You got a library where you are?
Otherwise look for books called Organic Synthesis.

[Messi]

Isn't there an easy procedure where with benzylamine as a starting reactant, I alkylate the benzylamine with bromobenzene to form the dibenzylamine?

[Dan]

I think it will be cheaper to buy it than to make it.

Is there a procedure for this?

Yes, I got 551 hits on Reaxys for preparing this compound - you should have access through your university. You should invest a little bit of time in finding answers yourself before asking on the forums - ChemicalForums is not a database search service. You will also find a number of patents on google in seconds.

Making secondary amines from primary amines by alkylation with alkyl halides is notoriously messy - it is a classic exam question problem. Bromobenzene (BrPh) is not a suitable reagent for benzylation. Benzyl = CH₂Ph.

Do you want to make dibenzylamine: (PhCH₂)₂NH (= Bn₂NH)
Or do you want diphenylamine: Ph₂NH

[discodermolide]

In this case you may get over alkylation, reductive amination is better.
In any case you don't want bromobenzene! You would need benzylbromide.


(Sorry Dan, we both clicked at the same time!)

[Messi]

Sorry, I meant to say benzylbromide.

And sorry Dan, I just don't know the websites where I can search for such things. I'll look for Reaxys.

[Messi]

Drat! My institution doesn't have access to Reaxys!

[organica]

just react benzylamine with benzyl chloride. add HCl and reflux it at 95 degree Celcius temperature for 1 hour. filtrate the impurities.

[Messi]

How would this procedure work for the synthesis of dibenzylamine?:

Procedure:
To a 10% solution of benzaldehyde (20mmol, 2.03ml) in glacial acetic acid (18.3ml) were added benzylamine with stirring. Sodiumborohydride pellets (0.02mol, 756.6mg) were added to it. The reaction mixture was left at room temperature with constant stirring for 2h. Then a 5% NaOH solution was added to the reaction mixture until the solution turned basic (pH ~ 9). The product was then extracted with two successive 15ml portions of dichloromethane. The combined extracts were dried over anhydrous Calcium Chloride. The solvent was evaporated under vacuum. The product was characterized by NMR.

[discodermolide]

Don't use pellets, use the powder.

[Messi]

Don't use pellets, use the powder.

Ok, good idea!

Does my proposed procedure seem correct though? By the way, I am very sorry for these plethora of questions. I am just trying to learn.