Sciencemadness Discussion Board

Are amino groups oxidised in the same way hydroxy groups are?

mycotheologist - 18-5-2012 at 10:52

I was pondering things to do with the hydrolysis product of acetaminophen (4-aminophenol) and thought about oxidising it with KMnO4. Would that yield 4-aminobenzoic acid or 4-nitrobenzoic acid?

[Edited on 18-5-2012 by mycotheologist]

sargent1015 - 18-5-2012 at 11:42

So which of these do you have?

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The one on the right is acetaminophen

UKnowNotWatUDo - 18-5-2012 at 14:53

He's saying that he has 4-aminophenol, which is the product you get when acetaminophen is hydrolyzed. However this will not yield any benzoic acid derivatives when oxidized as you are missing a carbon atom.

sargent1015 - 18-5-2012 at 15:51

Quote: Originally posted by UKnowNotWatUDo  
He's saying that he has 4-aminophenol, which is the product you get when acetaminophen is hydrolyzed. However this will not yield any benzoic acid derivatives when oxidized as you are missing a carbon atom.



Gotcha, thanks for that. :)

mycotheologist - 22-5-2012 at 05:33

Quote: Originally posted by UKnowNotWatUDo  
He's saying that he has 4-aminophenol, which is the product you get when acetaminophen is hydrolyzed. However this will not yield any benzoic acid derivatives when oxidized as you are missing a carbon atom.


Oh yeah, I didn't think of that. It can't yield a ketone without breaking the aromaticity either. Any idea what an oxidiation would yield? I know that reducing agents like NaBH4 indiscriminately reduce both nitro and carboxyl groups but I don't know if the same applies for the reverse reaction. I'm guessing not, otherwise there would be plenty of info on oxidising amino groups to nitro groups.

barley81 - 22-5-2012 at 06:45

Sodium borohydride is actually selective. It will not reduce carboxylic acids, but it will react with aromatic compounds containing nitro groups under special conditions.

http://pubs.rsc.org/en/content/articlelanding/1980/p2/p29800...
(NaBH<sub>4</sub> reduces 2,4-dinitrobenzene by displacing a nitro group with hydrogen. Nucleophilic aromatic substitution.)


http://pubs.acs.org/doi/abs/10.1021/jo00805a015
(Sodium borohydride can reduce aromatic nitro compounds to azoxy compounds)

Thread on oxidizing amine to nitro:
http://www.sciencemadness.org/talk/viewthread.php?tid=9091

[Edited on 22-5-2012 by barley81]

fledarmus - 22-5-2012 at 06:49

Amino groups can be oxidized to nitro compounds, but it is usually done with ozone or with peroxides. I don't believe I've ever seen a permanganate oxidation of an aromatic amine.

If there is a hydrogen available on the alpha carbon, the amines can be oxidized to the imine or enamine with subsequent reactions possible... http://pubs.acs.org/doi/abs/10.1021/jo01285a042

solo - 22-5-2012 at 08:24

Reference Information


Oxidation of primary, secondary, and tertiary amines with neutral permanganate. Simple method for degrading amines to aldehydes and ketones
Surjan S. Rawalay, Harold Shechter
J. Org. Chem.
1967, 32 (10), pp 3129–3131
DOI: 10.1021/jo01285a042

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