sonogashira
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Site of nucleophilic addition?
Say I had
R-C-CO2Me
.... ||
.... NCl
and I wanted to make
.... Et
.... |
R-C-CO2Me
.... |
.... NH2
Could this be achieved by reaction with EtMgBr, or would the presence of the Cl and ester groups prevent the reaction? Or perhaps more equivalents of
the Grigard would be needed?
I want to avoid making the ketone though.
Hoping that someone can be of help
[Edited on 11-1-2008 by sonogashira]
[Edited on 11-1-2008 by sonogashira]
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MagicJigPipe
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I have a limited knowledge of the mechanics of Grignard reactions but if I were to guess I would say you might have a problem. Go look under the
Wikipedia article. It has some good information and and 2 pretty convienient flow charts.
From what I see it will add to alkyl halide. N-Cl, not sure. Seems to replace tertiary amine groups as well. Anyway, I'll shutup now and let some
who knows what they're talking about answer you!
P.S. I would post the charts here but I got in trouble for posting stuff that certain people deem "standard knowledge". Now that I think about it,
everything is standard knowledge to somebody.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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polychemist
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I would like to say if you use Grignard reaction you will get a lot of byproduct because of the ester group as well as the Cl group. Maybe you can use
some catalyst such as Pd or Cu, probably it will help.
However, the product you got is very simple, it is just a methyl ester of some kind of amino acid, so I believe you may make this compound via another
route.
Water solubility?
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Nicodem
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An addition of ethyl Grignard on a N-chloroimine?
No way would it give you the desired product with one equivalent EtMgBr. If you count the oxidation states of the starting compound and the product
you can see the product is reduced. There would be many products formed but most likely none of the one you want.
The addition of ethyl Grignard on the imine could formally yield you the desired amino ester, but mind that esters also react with
Grignards although more slowly. Also, the intermediate magnesium amide (present before quenching with NH4Cl) can condense with esters, especially with
methyl esters, giving the appropriate amides (in your case piperazin-2,5-diones and similar amino acid dimers). Hence, even provided you could prepare
the alpha-imino esters, you would have a difficult/messy reaction after the Grignard addition.
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sonogashira
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Ok, thanks a lot for the help.
I'll get better one day... I hope!
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maniacscientist
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W(C)ouldn´t Grignard yield the oxime? then maybe a mild reduction of this to the amine?
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