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Filemon
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[*] posted on 11-8-2008 at 17:37
Reactivity amide


May a primary amide substitute a alkyl halide?
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Klute
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[*] posted on 11-8-2008 at 17:50


Do you mean may a primary amide be alkylated by an alkyl halide?

yes, it can. Depending on the amide, NaOH/KOH with ot without a PTC can do the job, otherwise you need to get the NaH out and form the anion befor eadding your alkyl halide. I haev recently requested several articles on the subject in the ref forum.

These could be usefull also:


alkyaltion of N-substitued phenylacetamides

Alkylation of N-substitued phenylacetamides: Benzylation of N-(4-chlorophenyl)-2-phenylacetamide

Look at the end of the experimental part of this article for an example of NaH alkylation in THF:
Synthesis of priamry amines by Pd2+ catalyzed deallylation

Hope it helps.

But if this is too form a primary amine by hydrolysis of the resulting secondary amide, you would better be off doing a Gabriel synthesis, the alkylation is much cleaner...

For secondary amines, this seems like a good route that avoids LiAlH4 reduction of amides. Reductive alkyaltion with short chain aldheydes (formaldehyde) seems pretty tricky and dialkylation happens to a certain extent.

[Edited on 12-8-2008 by Klute]




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[*] posted on 12-8-2008 at 06:50


Quote:
Originally posted by Klute
Do you mean may a primary amide be alkylated by an alkyl halide?


Exact. It is what wanted to know. They are resistant to the attacks of the alkyl halides.

Thank you.
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[*] posted on 12-8-2008 at 17:31


Quote:
They are resistant to the attacks of the alkyl halides.


Is that a claim, or a question? Because the final point is they are not... Of course, other more nucleophilic groups would be alkylated before an amide in the same molecule, but upon heating with alkyl halide, amides can be N-alkylated. That depends strongly on the structure of the amide, of the alkyl halide, and of the reaction conditions.

In one of the above articles, they details the different products obtaien din different condition (neutral, basic), giving rise to N-, O- or even C-alkylation products.

I'm afraid without any more info on what you want to know, and on the compounds, it impossible to give a definate answer.




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[*] posted on 18-8-2008 at 02:13


Some amides get alkylated particularly easily with strong alkylating reagents. For example, N,N-dimethylformamide gets O-methylated with dimethylsulfate just by letting the mixture of the two standing for a longer time.



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