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Topic: how to convert Nitriles to amide?  (Read 22060 times)

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Offline Chaste

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how to convert Nitriles to amide?
« on: April 23, 2009, 09:16:07 AM »
Hi all, is this a single step process? or are there several steps arriving to the amide? and what are its reactants and conditions?

thanks

Offline nj_bartel

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Re: how to convert Nitriles to amide?
« Reply #1 on: April 23, 2009, 09:58:30 AM »
Only way I can think of is three steps.

Offline aldoxime_amine

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Re: how to convert Nitriles to amide?
« Reply #2 on: April 23, 2009, 11:12:59 AM »
I think I may have heard something about hydrolysis in presence of H2O2 stops it at the amide stage. Maybe someone can give a reference...

Offline azmanam

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Re: how to convert Nitriles to amide?
« Reply #3 on: April 23, 2009, 11:26:18 AM »
From Brown & Foote:

Quote
The reaction conditions required for acid-catalyzed hydrolysis of a cyano group are typically more vigorous than those required for hydrolysis of an amide, and in the presence of excess water, a cyano group is hydrolyzed first to an amide and then to a carboxylic acid.  It is possible to stop at the amide by using sulfuric acid as a catalyst and one mole of water per mole of nitrile.  Selective hydrolysis of a nitrile to an amide, however, is not a good method for the preparation of amides.  They are better prepared from acid chlorides, acid anhydrides, or esters.
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Offline darien2009

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Re: how to convert Nitriles to amide?
« Reply #4 on: June 22, 2009, 09:43:37 AM »
Hi, let us take for example:

 step1:  reduce ph-CH2CN with H2/Ni, heat give phCH2CH2NH2

step2:  then phCH2CH2NH2 + R-COCl give R-CONHCH2CH2ph

Offline Squirmy

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Re: how to convert Nitriles to amide?
« Reply #5 on: June 22, 2009, 09:51:02 AM »
How about the Ritter reaction?

Offline AWK

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Re: how to convert Nitriles to amide?
« Reply #6 on: June 22, 2009, 10:36:17 AM »
AWK

Offline orgopete

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Re: how to convert Nitriles to amide?
« Reply #7 on: June 22, 2009, 07:23:37 PM »
I think I may have heard something about hydrolysis in presence of H2O2 stops it at the amide stage. Maybe someone can give a reference...

Just a follow up. A peroxide reference from Katritzky is here. Search "nitrile hydrogen peroxide".

I note that Katritzky also argues that base catalysis of a nitrile ends at a carboxylic acid. This is what I wrote in my book. A nitrile will hydrolyze all the way to a carboxylic acid (unless limited by water) because the amide intermediate is more basic than the nitrile starting material. This encourages its continued reaction over the less reactive or lower concentration of protonated nitrile.

In the case of a base hydrolysis, it is easier to stop at an amide as the conditions for amide hydrolysis requires formation of the dialkoxy anion. Thus, if insufficiently basic or concentrated conditions are used, the reaction can stop at the amide stage. (That had been my experience in the lab as well.) However, your mileage may vary.
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