Formation of imines from primary amines and ketones

by James

Description: Reaction of a primary amine with an aldehyde or ketone results in an imine. The reaction results in the formation of one equivalent of water.
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{ 7 comments… read them below or add one }

sreekanth September 27, 2012 at 8:45 am

why primary amines under diazonium reaction

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james September 30, 2012 at 9:13 am

If you use secondary amines you can’t form the triple bond.

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Seah November 2, 2013 at 1:15 pm

For the first step, why does e proton source attack the carbonyl oxygen instead of the more basic amine in the reaction mixture? Is it because of resonance in e protonated carbonyl?

Do we add e acid and e amine at the same time?

Can the acid be a weak acid as strong acidic conditions may protonate e amine and render it non nucleophilic?

Thanks :)

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Rich Aversa October 17, 2014 at 10:04 pm

I was wondering this as well.

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James October 19, 2014 at 2:06 pm

The amine is more basic, this is true! Acid can attack the amine, but it doesn’t go anywhere (the amine and protonated amine are in equilibrium). It’s a dead end, in other words.

You just need a little bit of protonated carbonyl to get the reaction going.

It’s important that the solution not be too acidic, since if all the amine is protonated (irreversibly) then there is no nucleophile that would be able to attack the carbonyl.

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eabee December 11, 2014 at 9:59 am

My textbook shows this reaction in water. Without acid, is the carbinolamine a stable form?

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James December 17, 2014 at 4:07 pm

Imine formation IN water – or is it imine hydrolysis?

Imine formation in water is not going to be successful unless you are forming a particularly stable imine (such as a cyclic 5 or 6 membered imine) and even then you’ll probably get a lot of the carbinolamine.

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