morsagh
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Betaine methylation
Can be betaine used for methylation an amino group (and in which conditions)?
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AvBaeyer
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The simple answer is no.
AvB
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Yugen
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Actually it might work... people use tetramethylammonium to methylated phenols (using basic conditions & microwave heating), so why not amines
with a different quaternary ammonium ion? I doubt you are gonna have much control over the types of products you get (probably all tertiary amines
because the more alkyl groups an amine gets, the easier if becomes to add another alkyl group).
But who knows until it's actually tried right? Try adapting this paper's procedure.
http://www.sciencedirect.com/science/article/pii/S0040402008...
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Haber
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Are you sure about this? Could you explain why this is the case?
I would have thought of the opposite, mainly because of sterical hindrance, but also wouldn't the alkyl groups reduce the nitrogens nucleophility?
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Dr.Bob
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For small alkyl groups, each extra methyl on a nitrogen makes it more nucleophilic in general. That is why it is hard to make methylamine or
dimethylamine, as each of those is methylated faster than ammonia. If you add isopropyl groups, for instance, it become more sterically hindered,
which is why diisoproylethylamine (DIEA, Hunig's base) is used as a mostly non-reactive base, but even that can react with some alkylating agents
under harsh conditions.
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Nicodem
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Thread Moved
9-1-2015 at 12:33 |
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