[Jasmineunknown]

Dear all,

This is the background to my problem. I am making amides by reacting them with carboxlic acids.

I am using are primary amine (aniline) shown as 1 and secondary amine shown as 2.

The yield was higher for 2 and my proposal was that it could be due to the secondary amine on 2 is more nucleophilic as it is not resonance stabilised by an aromatic ring compared to the aniline in 1.

The problem is my lecturer says this explanation is wrong and I need to re-write it.

I am confused as I can’t think of another reason.

Really would appreciate some help with this.
Thanks!

[fledarmus]

I'm not sure exactly what your lecturer is trying to get at, but there are at least two other ways you might consider differences between the two - hybridization and pKa. Does that help any?

[AWK]

Let's take a simpler example: unsubstituted aniline and cyclohexylamine
( http://en.wikipedia.org/wiki/Cyclohexylamine ). Which one is more reactive and why?

[zoork34]

Could it be a matter of just expanding on your explanation?   Something like "The lone pair of electrons on the nitrogen of aniline are partially delocalized into the aromatic ring, while the lone pair of electrons on the secondary amine are not delocalized at all."    I know thats basically what you said, but I cannot think of anything wrong with it. 

[AWK]

What kind of substituent is at amino group?

[camptzak]

does compound 1 accept a proton from a carboxylic acid forming a stable ionic pair?
also, did you catalyze this reaction with anything or did you just mix and heat the two at neutral pH?

[camptzak]

Let's take a simpler example: unsubstituted aniline and cyclohexylamine
( http://en.wikipedia.org/wiki/Cyclohexylamine ). Which one is more reactive and why?

I would say cyclohexylamine because it has greater electron density at the nitrogen. The Aniline's aromatic group woud be electron withdrawing from the nitrogen.

Also it seems like the resulting amide would be more stable for the same reason.
is this correct?

[AWK]

First of all think about general classification of organic compounds
Phenyl - aryl
cyclohexyl - alicyclic - alkyl