Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Chaste on April 23, 2009, 09:16:07 AM
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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
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Only way I can think of is three steps.
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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...
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From Brown & Foote:
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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Hi, let us take for example:
step1: reduce ph-CH2CN with H2/Ni, heat give phCH2CH2NH2
step2: then phCH2CH2NH2 + R-COCl give R-CONHCH2CH2ph
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How about the Ritter reaction (http://en.wikipedia.org/wiki/Ritter_reaction)?
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How about the Ritter reaction (http://en.wikipedia.org/wiki/Ritter_reaction)?
But it forms N-alkylamides
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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 (http://ufark12.chem.ufl.edu/Published_Papers/PDF/045-MASS.pdf). 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.