morsagh
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Diamines alkylation
What are products of alkylation of some diamine (for example putrescine or cadaverine) with two moles equivalent of ethyl chloride? Does it produce
only secondary amines (like 1,6-diethylputrescine) or it goes to tertiary (like 1,1-diethylputrescine) how efective is this for producing secondary
compound? What happens if some sterically hindered alkyl halide is used, like terc.-butylchloride? Is the yeld of secondary amine better?
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zhiang0113
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I think the tertiary amine would be favoured, since the electron-donating effect of the added alkyl group will make the lone pairs on the nitrogen
atom more nucleophilic. I suppose bulky substituents would make the amine less nucleophilic though, that should favour the secondary amine more.
Perhaps you could convert it to an amide first (using ethanoyl chloride), then reduce the amide? That would require strong reducing agents like
lithium aluminium hydride though.
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CuReUS
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zhiang is right,tertiary amine will be favoured.And bulky substituents favor secondary because they are.......bulky
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morsagh
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I can´t find any reference to dialkylation of diamine... So better try aldehyde amine condensation and NaBH4?
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clearly_not_atara
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If you want symmetrical secondary amines, you might be able to do this by alkylating the cyclic aminal formed with benzaldehyde.
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CuReUS
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I found a reference using iodoethane and diaminoethane(similar to your compound) to get the corresponding symmetrical diamine.Sadly,only the pg nos
are given(389 and 517,521) not the issue so its very difficult to find.If you are really interested,you could go through each issue till you find
it.
it is in this journal - http://onlinelibrary.wiley.com/doi/10.1002/ardp.186717901100...
| Quote: | | So better try aldehyde amine condensation and NaBH4? |
instead of NaBH4,you could try hydrogenation
http://pubs.acs.org/doi/abs/10.1021/jo01083a021
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Dr.Bob
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You will most often get a statistical mixture of primary, secondary, tertiary, and sometimes quat. amines. It depends on the amine, the alkylating
agent (leaving group and steric bulk), and the conditions. Predicting the exact outcome without some details or previous references is like
predicting the outcome of the Superbowl next year. There are many tricks to make specific mono or dialkylations, like using an acetyl group and
then reducing that to an ethyl. But all are substrate and alkyl group dependent.
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Nicodem
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10-6-2016 at 10:22 |
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