Sciencemadness Discussion Board

Amide vs ester selectivity

deltaH - 12-2-2016 at 12:02

If a molecule has both a primary amine and secondary hydroxyl functional groups and you form the formate salt of it, upon strong heating, would you form predominantly the formamide or formate ester or mixture of both without a major dominance of one over the other?

deltaH - 15-2-2016 at 09:48

I have just read on wikipedia that amides may be formed by the reaction of an amine with an ester, something called ester aminolysis, so I guess I can answer my own question, at least superficially. So if you have both a secondary hydroxyl group and amine group on your molecule and use one equivalent of acid, ultimately, forming the amide should dominate?

Etaoin Shrdlu - 15-2-2016 at 13:49

Likely would. Amides are more stable than esters because the lone pair on nitrogen delocalizes very well into the pi system, making the carbon less electrophilic.

deltaH - 15-2-2016 at 22:08

Quote: Originally posted by Etaoin Shrdlu  
Likely would. Amides are more stable than esters because the lone pair on nitrogen delocalizes very well into the pi system, making the carbon less electrophilic.


Nice explanation Etaoin Shrdlu, makes a lot of sense, thanks!

[Edited on 17-2-2016 by deltaH]

zed - 16-2-2016 at 19:19

Amide? Maybe. There is a certain possibility of aziridine type formation via dehydration.

A purported possible intermediate in the HI/P reduction of ephedrine , is a three membered ring, with the amino function Bridging the Alpha and Beta carbons.

So, how much heat?

Enough heat and pressure, may result in the amino function being
alkylated by the alcohol.

Amides may also be alkylated by this method.


byko3y - 16-2-2016 at 20:46

You can produce one, or another, or mixture of products depending on conditions and reagents.

deltaH - 16-2-2016 at 21:27

My compounds are not volatile, so I'm heating to 150°C for about an hour in my initial experiments.