amides

[carol]

acid+amine=amide. should it be more specific like carboxylic acid+amine=amide? (might be just a stupid question, sorry)

[woelen]

I think that you are right and that the amide (peptide) group is a naming convention, specific for the -C(=O)-N(H)- group. With other acids, such groups exist, but IIRC then they are not called amide.

[RyanJ]

I think that you are right and that the amide (peptide) group is a naming convention, specific for the -C(=O)-N(H)- group. With other acids, such groups exist, but IIRC then they are not called amide.

 

You are correct, my organic chemistry textbook says that the amide group is: [ce]-C(=O)-N(H)-[/ce] and the name wouldn't be the same if there were no carboxylic acid group (e.g. it wouldn't form an amino acid any more). I'm not sure of the names of these compounds though because there are probably a few of them

 

Another reason this may be said as such because the most common acid group (and most important) is the carboxylic acid group and it is therefore generally assumed to be the one in use

[John Cuthber]

Sulphonic acids give sulphonamides, phosphoric acids give phosphoramides carbamides are another variation on the theme too.

[carol]

thank you, thank you. it just bothers me because i can't defend my answer to my teacher.

[budullewraagh]

Well, if you take a carboxylic acid and react it with ammonia, over the span of weeks you'll get the amide. This isn't a good reaction, but it eventually goes forward as the reversible proton exchange between the ammonia and carboxylic acid sees competition with the nucleophilicity of the ammonia, which is nucleophilic towards the acid but not the carboxylate anion. This reaction won't work with alkylamines because they are too basic and the reaction is hindered by sterics.

 

A much better way to do it is to do a Weinreb Amidation after forming a simple ester with the acid. This requires the amine, ester, and an aluminum (dimethylchloroaluminum works well) catalyst.