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Topic: oxidations....for professionals  (Read 5996 times)

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The Good Doctor

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oxidations....for professionals
« on: August 15, 2005, 06:05:09 PM »
HI!

Just got a problem. I am trying to make an oxidation of (for example) p-amino toluene with KMnO4 to the carbon acid. The side product is the formation of the aza compound. Does anyone knows another good oxidation method(s) avoiding the side product formation?
P.s. CrO3 does not work with my molecule when i have an ethyl moiety, the ketone is only formed with KMnO4, but still got this aza formation!!! :-[
thx

laotree

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Re:oxidations....for professionals
« Reply #1 on: August 15, 2005, 06:09:03 PM »
Go ahead protect you aniline with BOC, or CBZ, or, Fmoc etc. Then do your oxidation.

The Good Doctor

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Re:oxidations....for professionals
« Reply #2 on: August 15, 2005, 06:11:36 PM »
Thanks for the *delete me*

Yeah i know it should be nice but.....the next step should be a wittig reaction, and am affraid of the acidity of the protecting group... :'(

The Good Doctor

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Re:oxidations....for professionals
« Reply #3 on: August 15, 2005, 06:13:39 PM »
...cause u still should have an amide with certain acidity..

The Good Doctor

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Re:oxidations....for professionals
« Reply #4 on: August 15, 2005, 06:16:15 PM »
To make it more better explanation i want to make a wittig and then transform the aniline moiety to an sulfon amide (too acidic off course...)
If my explanation is not clear i can send u an drawing..
thx anyway

The Good Doctor

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Re:oxidations....for professionals
« Reply #5 on: August 15, 2005, 06:22:53 PM »
Should H2O2 be perhaps amore selective method?
tgd ???

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Re:oxidations....for professionals
« Reply #6 on: August 15, 2005, 06:34:34 PM »
I don't think H2O2 would work.  It might also oxidize the amine to the N-oxide.

If you want the sulfonamide, what about making the bis-sulfonamide of the aniline and then cleaving one off after the oxidation and Wittig reactions?

The Good Doctor

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Re:oxidations....for professionals
« Reply #7 on: August 15, 2005, 07:00:26 PM »
By the way, if anyone has troubles with an oxidation that does not work (or works hard) try KMnO4/MnO2 with Amberlite IRA-904 (in dichloromethane as solvent)..kicks ass!:) no kidding!
 ;)

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