Dr.Q
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Amino Acetone
I read that in alkillation of amines/amonnia , they can act as a nucleophiles to create amines. Like NH3 and ethyl bromide would give ethyl amine and
further more alkliation di ethyl amine and so on.
I wonder that can this be applied to ketones. For example could chloroacetone can a substition with amonnia beside attakc to double bond carbon ?
Could this can create amino acetone ?
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Nicodem
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19-2-2013 at 09:03 |
Nicodem
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Do you have a reference?
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
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Dr.Q
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alkillation of amonnia or amines wrights in solomons organic chemistry.
The other is the thing that i wonder for ? No refferance for that
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AndersHoveland
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I have always been confused why hydroxyacetone reacts with ammonia in the way that it does.
Why does aminoacetone not form? Is aminoacetone even stable?
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Nicodem
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Aminoacetone is not a stable compound. It decomposes relatively rapidly. It is however completely stable in acidic media and can be isolated in the
form of its salts (see literature examples of its preparation, where it is always prepared as a salt isolated from acidic media).
It is not prepared by alkylation of ammonia with haloacetones. There have been historic attempts into preparing it this way and some claimed they
isolated it from the product mixture, but the most conclusive attempts indicate this is not possible (see: Gabriel, Ber. 1893, 2197; the
article is freely accessible at Gallica). As I understood the article, the main product isolated from the related reaction of 3-chloro-2-butanone with ammonia was
2,3,5,6-tetramethylpyrazine (thus the aromatized self condensation product of the initially formed aminoketone).
That is no reference in support of your assumption that aminoacetone should form. Firstly, because aminoacetone is an alpha-aminoketone and thus
unstable in basic media. Secondly, because you used a faulty deduction. Chloroacetone and other alpha-halo carbonyl compounds do not behave like alkyl
halides due to the neighboring group assistance. They are isoelectronic with allyl chlorides and therefore do not react via a simple SN2 mechanism. In
fact, I'm not sure there are any conclusive evidence for the mechanism of the nucleophilic displacement at alpha-haloketones. I have not checked for
the latest literature, but I have a book from 1963 (C. A. Bunton: Nucleophilic substitution at a saturated carbon) that provides a number of
hypotheses to explain the reactivity of alpha-halo carbonyl compounds and none seem fully convincing.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Dr.Q
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Quote: Originally posted by Nicodem  | Aminoacetone is not a stable compound. It decomposes relatively rapidly. It is however completely stable in acidic media and can be isolated in the
form of its salts (see literature examples of its preparation, where it is always prepared as a salt isolated from acidic media).
It is not prepared by alkylation of ammonia with haloacetones. There have been historic attempts into preparing it this way and some claimed they
isolated it from the product mixture, but the most conclusive attempts indicate this is not possible (see: Gabriel, Ber. 1893, 2197; the
article is freely accessible at Gallica). As I understood the article, the main product isolated from the related reaction of 3-chloro-2-butanone with ammonia was
2,3,5,6-tetramethylpyrazine (thus the aromatized self condensation product of the initially formed aminoketone).
That is no reference in support of your assumption that aminoacetone should form. Firstly, because aminoacetone is an alpha-aminoketone and thus
unstable in basic media. Secondly, because you used a faulty deduction. Chloroacetone and other alpha-halo carbonyl compounds do not behave like alkyl
halides due to the neighboring group assistance. They are isoelectronic with allyl chlorides and therefore do not react via a simple SN2 mechanism. In
fact, I'm not sure there are any conclusive evidence for the mechanism of the nucleophilic displacement at alpha-haloketones. I have not checked for
the latest literature, but I have a book from 1963 (C. A. Bunton: Nucleophilic substitution at a saturated carbon) that provides a number of
hypotheses to explain the reactivity of alpha-halo carbonyl compounds and none seem fully convincing. |
Could you explain me that why aminoacetone is unstable ???
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DraconicAcid
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One reason is probably that amines can react with ketones to give imines. Look up "imines" in the index of Solomons (I don't have a copy of that text
anymore, but I'm sure it's in there). If you make the aminoketone, it could very well react with itself to give another product. I had forgotten
about that particular reaction when I made my first reply (now deleted after Nicodem quite rightly requested a reference, for which I had none).
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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