Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Archer on December 24, 2013, 03:43:48 PM
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I am trying to add an amine to a molecule by reaction of Hexamethylenetetramine with my molecule which is an α-bromoketone.
I am following a literature procedure which seems simple enough, mix 50 mmol of each substance in 200 ml of chloroform, heat to 50°C for one hour and filter off the product.
50°C degrees for an hour made very little precipitate. Today I heated to reflux (60°C) for 7 hours and the precipitate collected was only about 8% of theoretical.
GC-MS of the filtrate shows is very clean, only the two starting materials present. So I can continue to heat and be patient.
This sluggish reaction is not ideal so I was hoping for any tips on how to speed things up a bit. I have considered a higher boiling solvent.
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Perhaps use toluene and add some DMAP?
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There are solubilty issues with toluene but DMAP is worth a try, although this my just irreversibly alkylate the DMAP. Otherwise I may have to recover my starting material and try Finklestein.
Thanks Discodermolide and Happy Christmas.
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Definitely try adding some NaI.
If that doesn't help, have you tried going through the azide?
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Another easy thing to try would be using a solvent that is more likely to precipitate a salt, like benzene.
If that doesnt work, use acetonitrile or DMF, heat it up quite a bit (I'd try reflux for the acetonitrile, and maybe 70-90 C for the DMF). Then, once it has cooled down, precipiate your product by dropping your reaction into some diethylether or THF.