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Topic: Washing out 2,6-Lutidine  (Read 11554 times)

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Sulfinator

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Washing out 2,6-Lutidine
« on: June 02, 2006, 03:42:19 PM »
Hello all, I have a question regarding removal of lutidine from a reaction. I am using 2,6-lutidine as a base in a sulfinylation of an alcohol and I would like to remove it by washing or chromatography.  At this point, I don't know enough about sulfinate esters to know whether or not they are labile during chromatography. In a test reaction with neopentyl alcohol, a sulfuric acid wash step removed the lutidine.  However, my alcohol has an acid-labile protecting group elsewhere in the molecule, so this step would not work.  When I have run sulfonylation reactions with triethylamine as a  base in the past, I have used bicarbonate washes to remove the excess triethylamine successfully.  However, bicarbonate did not remove the lutidine in our test reaction, based in H-1 NMR.  Someone suggested that a copper sulfate wash can remove pyridine, and that it might work with lutidine also. Does anyone have any suggestions as to the removal of this base? Any input is appreciated, thank you.

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Re: Washing out 2,6-Lutidine
« Reply #1 on: June 03, 2006, 03:27:54 PM »
I've heard that the copper sulfate wash works great, but I haven't actually done it myself.  Lots of people in my lab have used it with success though.

You might also try aqueous sodium citrate.  I have used that to remove triethylamine hydrochloride with great results.  I'm not certain that it would work with lutidine though.

Offline Babcock_Hall

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Re: Washing out 2,6-Lutidine
« Reply #2 on: February 24, 2017, 04:35:00 PM »
We are trying to find a way to remove collidine.  We used copper sulfate to remove lutidine one time many years ago, but I don't remember who gave us the idea.  We found one thread at Research Gate about using copper sulfate to remove pyridine, and they noted that there was a color change.  Does anyone have a good reference or some practical tips to share?
https://www.researchgate.net/post/What_is_best_method_to_remove_pyridine_from_a_reaction_mixture

Offline wildfyr

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Re: Washing out 2,6-Lutidine
« Reply #3 on: February 27, 2017, 09:18:48 AM »
I've had some general success with using copper to remove amines, especially pyridine. I think its worth just trying the wash in a scint vial with an aliquot amount and checking the purity by NMR.

Offline Babcock_Hall

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Re: Washing out 2,6-Lutidine
« Reply #4 on: February 27, 2017, 12:16:23 PM »
I did not see your comment until just now, but I think trying it on a small scale makes sense.  When my student tried it on the whole reaction, a precipitate formed.  I am not sure what precipitated out.

Offline wildfyr

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Re: Washing out 2,6-Lutidine
« Reply #5 on: February 27, 2017, 01:13:38 PM »
Just to be clear, by copper, I mean copper sulfate aqueous solution, not the Cu(0) metal  ;)

Offline rolnor

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Re: Washing out 2,6-Lutidine
« Reply #6 on: February 27, 2017, 03:55:53 PM »
If the lutidine is free base, would not freeze-drying remove it? Not so high boilingpoint.

Offline Babcock_Hall

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Re: Washing out 2,6-Lutidine
« Reply #7 on: February 27, 2017, 04:48:21 PM »
For this reaction we used collidine, but perhaps if we run it again, we can substitute in lutidine.  Thank you; I would not have thought of freeze drying.

Offline Optimist

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Re: Washing out 2,6-Lutidine
« Reply #8 on: February 27, 2017, 09:47:01 PM »
In my opinion it CuSO4 will also work for  lutidine, Just try with small quantity before going on large scale.

Offline wildfyr

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Re: Washing out 2,6-Lutidine
« Reply #9 on: February 28, 2017, 01:41:18 PM »
I'm not 100% sure but I think CuSO4 works for amines generally... I feel like I got triethylamine off using it one time.

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