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Author: Subject: hydrolysis amine of a keto-alpha amine
Filemon
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[*] posted on 30-4-2008 at 13:41
hydrolysis amine of a keto-alpha amine


May it hydrolyze a amine of a keto-alpha amine with heated in strong aqueous acid?
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grind
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[*] posted on 30-4-2008 at 18:47


Do you mean R-CO-CH2-NR´R´´? You can´t hydrolyze that. By the way, it´s called amino ketone.
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Nicodem
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[*] posted on 1-5-2008 at 10:15


In molecules that have no hydrolysable bonds, no hydrolysis can occur.
Filemon, are alpha-aminoketones really what you are talking about? I'm unsure if Grind guessed correctly. Why don't you use a rational formula for better understanding.
alpha-Aminoketones only get protonated in acidic aqueous media. Heating such solution would probably result in some decomposition, but since there is nothing to hydrolyze no hydrolysis can occur. Many alpha-aminoketones are also fairly unstable as free bases so they are generally prepared as their salts (hydrochlorides etc.).




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[*] posted on 2-5-2008 at 05:09


This molecule: amino-acetone => 2-hydroxy-propanal
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Nicodem
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[*] posted on 2-5-2008 at 09:03


That would require the aminoacetone to enolize to the side of the amino group, the so formed enamine (H<sub>2</sub>N-CH=C(OH)-Me) would have to tautomerize to the imine (HN=CH-CH(OH)-Me) and this finally hydrolyze. As you see there are several steps before you get to a compound that has a hydrolysable bond and all these steps are highly reversible. Furthermore, under acidic conditions the aminoketone is protonated and this inhibits some of the steps even though it promotes the enolization (but I don’t know to which side!), so it is a matter of what is more influential. Too harsh acidic conditions are also detrimental to the end product. Most such aldehydes are not particularly stable in highly acidic media and this one in particular can also easily convert to hydroxyacetone.
I know of no example in the literature of this particular reaction. Essentially, what you are proposing is a reversal of the Amadori rearrangement. I could only find one such example and it is catalyzed with a mild base. It is the conversion of cathinone and its N-methyl derivative to 1-phenyl-1-hydroxyacetone using aqueous sodium acetate:

Optically active phenylpropanolamine derivatives. VIII. Preparation of dimeric ethers of phenylpropanolamines.
Takamatsu, Hideji.
Yakugaku Zasshi, 76 (1956) 1241-1243.

Unfortunately the abstract (Chem. Abs. 51:21611) says nothing about it and only Beilstein refers to this paper as describing the above mentioned reaction. So it would be necessary to check the paper, but I do not have access to Journal of Pharmaceutical Society of Japan (Yakugaku Zasshi). So, even though Beilstein mentions this reaction, I’m still very skeptical as it might be an abstraction error, especially if considering that these aminoketones self condense in basic media and get oxidized to substituted pyrazines.




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MagicJigPipe
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[*] posted on 2-5-2008 at 09:24


Surely there must be easier ways to lactaldehyde. Apparently it is normally produced from 1,3-propanediol via fermentation with a certain bacteria (for some reason my computer is screwed and I can't view the page that says this, sorry).

What reaction will you be using the it for?




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[*] posted on 6-6-2008 at 06:42


Optically active phenylpropanolamine derivatives. VIII. Preparation of dimeric ethers of phenylpropanolamines.
Takamatsu, Hideji.
Yakugaku Zasshi, 76 (1956) 1241-1243.


............unfortunately the publisher only has these archived issues but doesn't include the issue needed,


YAKUGAKU ZASSHI
Vol.86-105 No.1-12
Vol.106 No.1,11,12
Vol.107-120 No.1-12

..........source,

http://www.journalarchive.jst.go.jp/english/jnltop_en.php?cd...




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