November 28, 2024, 03:44:56 PM
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Topic: Alcohol to Ketone in the Presence of an Unprotected Amine  (Read 3084 times)

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Offline TwistedConf

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Alcohol to Ketone in the Presence of an Unprotected Amine
« on: October 21, 2014, 03:27:23 PM »
I need to oxidize a secondary alcohol to ketone in the presence of an unprotected secondary aromatic (aniline-type:  benzene-NH-R).  These are not common in the literature.

Dess-Martin or methods that use acidic conditions so that the amine is "protected" by protonation come to mind.

Anyone have any suggestions before I start the trials?


Offline discodermolide

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Re: Alcohol to Ketone in the Presence of an Unprotected Amine
« Reply #1 on: October 21, 2014, 07:56:13 PM »
I appreciate the protonation route as a means of amine protection, but do you trust the amine to remain protonated throughout the entire oxidation reaction and work-up?
I don't, but then I have no idea what you will be using for the oxidation.

Better to put a Boc on that nitrogen, oxidise and remove the Boc with acid to give the amine salt.
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Offline C-hemCards

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Re: Alcohol to Ketone in the Presence of an Unprotected Amine
« Reply #2 on: October 21, 2014, 09:44:35 PM »
Discodermolide makes a valid point. That being said, I'd give it a go with Dess-Martin. I think that will probably work unless the secondary alcohol is horrendously hindered.

Another option is to add an equivalent of AcOH to the rxn mixture before the oxidation.
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Offline Dan

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Re: Alcohol to Ketone in the Presence of an Unprotected Amine
« Reply #3 on: October 22, 2014, 03:22:56 AM »
Maybe TFAA/DMSO? This should temporarily protect the aniline as the TFA amide, which should hydrolyse easily with a basic workup.
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