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Topic: Ar-CH3 -> Ar-COOH  (Read 13010 times)

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Offline THC

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Ar-CH3 -> Ar-COOH
« on: February 11, 2008, 07:55:40 AM »
What is this process called?

Toluen -> Benzoic acid

KMnO4 is used as oxidizer.
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Offline russellm72

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Re: Ar-CH3 -> Ar-COOH
« Reply #1 on: February 11, 2008, 10:06:12 AM »
Oxidation... I don;t know if it has a process name....

It's a bit harsh but works Ok assuming you dont have much else in your molecule for it to chew up..
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Offline THC

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Re: Ar-CH3 -> Ar-COOH
« Reply #2 on: February 12, 2008, 12:40:24 AM »
Is it comparable to ozonolysis?
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Offline djay

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Re: Ar-CH3 -> Ar-COOH
« Reply #3 on: February 12, 2008, 02:32:24 AM »
No, because Ozone breaks all the double bonds to form Aldehydes/ketones while in this reaction you're adding OOH.

Dont know the name (maybe if you find the reaction mechanism it might help) but I remember that a friend of mine did that experience and the yield was less 15% and if you leave KMnO4 and Ar-CH3 for a long time, the reaction will be close to ozonolysis with some secondary products.
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Offline THC

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Re: Ar-CH3 -> Ar-COOH
« Reply #4 on: February 12, 2008, 03:16:00 AM »
"Alkenes can be oxidized with ozone to form alcohols, aldehydes or ketones, or carboxylic acids." from http://en.wikipedia.org/wiki/Ozonolysis

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Offline adam

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Re: Ar-CH3 -> Ar-COOH
« Reply #5 on: February 12, 2008, 03:52:55 AM »
Posted by: djay
a friend of mine did that experience and the yield was less 15% and if you leave KMnO4 and Ar-CH3 for a long time, the reaction will be close to ozonolysis with some secondary products.

First the toluene oxidize to  benzilic alcohol, then to benzaldehyde an finally to benzoic acid, the subproducts are the alcohol and the benzaldehyde.
If you leave the reaction for a long time you should obtain the benzoic acid as the major product
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Offline sjb

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Re: Ar-CH3 -> Ar-COOH
« Reply #6 on: February 12, 2008, 04:02:33 AM »
Quote from: djay on February 12, 2008, 02:32:24 AM
No, because Ozone breaks all the double bonds to form Aldehydes/ketones while in this reaction you're adding OOH.

.. and removing H3

Quote from: djay on February 12, 2008, 02:32:24 AM
Dont know the name (maybe if you find the reaction mechanism it might help)...

I thought it was basically sequential benzylic oxidations, given that e.g ethylbenzene and isopropylbenzene also react in a similar fashion

Quote from: djay on February 12, 2008, 02:32:24 AM
... but I remember that a friend of mine did that experience and the yield was less 15% and if you leave KMnO4 and Ar-CH3 for a long time, the reaction will be close to ozonolysis with some secondary products.

Obviously substrate dependent to an extent, I have done similar on at early stages of analogues of compounds like SB-590885 or L-779450, relatively mild (refluxing ethanol, overnight, ~ 70% isolated yield which for effectively 3 reactions in one pot IMO isn't too bad)

S
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