[peptideismylife]

I would like to ask you if I could see in the 1HNMR spectra the amino protons in DMSO. As far as I know the fast chemical exchange between the solvent and the amino protons don't permit us to show the amino protons in NMR....

[discodermolide]

I would like to ask you if I could see in the 1HNMR spectra the amino protons in DMSO. As far as I know the fast chemical exchange between the solvent and the amino protons don't permit us to show the amino protons in NMR....

May I ask what the level of your qualifications in organic chemistry is? Are you a post or under-graduate?

[peptideismylife]

I am a graduate...

[discodermolide]

I am a graduate...

OK, Thanks.
My feeling is that you should know the answer, or know where to look for it, especially if you are thinking of progressing towards a higher degree.

[peptideismylife]

jeje

For different reasons i don't have a good background in this field. I would say that in DMSO the fast chemical exchange is slow compare to other solvents. And for that reason I would imagine that we could show the amino protons in the NMR spectra. But I was not sure...if u know and u could confirm it...would be really nice from u...

Also I would like to ask if there are a better solvent to show this protons...

[discodermolide]

jeje

For different reasons i don't have a good background in this field. I would say that in DMSO the fast chemical exchange is slow compare to other solvents. And for that reason I would imagine that we could show the amino protons in the NMR spectra. But I was not sure...if u know and u could confirm it...would be really nice from u...

Also I would like to ask if there are a better solvent to show this protons...

That would seem to be correct.
DMSO is the best solvent for this.
Run the spectrum in DMSO then run an spec. with added D2O, just for the case that the NH2 signal is obscured by other signals.

[peptideismylife]

If I do like that then I will show a higher signal to the amino protons?

[discodermolide]

If I do like that then I will show a higher signal to the amino protons?

No. The spec on DMSO showed show a broad triplet integrating for 2H.
If you then add D2O (one drop) and shake the NH2 protons will exchange with D and the signal will disappear. This is very useful especially if the NH, NH2, OH signals are obscured by others. Measure the integral before and after exchange.

[peptideismylife]

Oh really thanks for your *delete me*

Last question...in which chemical shift appears the amino group? Its depending of the environment? I mean, in my case I chain of 4 methylens and at the end I have an amino group...or it's pH depending...

[Doc Oc]

I've done quite a few amino acid/peptide NMRs and visualization of the amine/amide protons is not always guaranteed.  When you do see them, they are often gentle humps that are not well defined/split and do not integrate neatly to 1/2/3 protons.  Most of my compounds were organic soluble enough that I could get them into CDCl₃, but I don't know if there's a way to enhance the strength or splitting of those protons.

Yes, the environment does affect the shift.  The amide protons I had showed up in the 5-6 ppm range and free amines more in the 2-3 ppm range (again, using CDCl₃ as solvent).

[discodermolide]

Oh really thanks for your *delete me*

Last question...in which chemical shift appears the amino group? Its depending of the environment? I mean, in my case I chain of 4 methylens and at the end I have an amino group...or it's pH depending...

There are many NMR simulation programs available you could find one on the Internet and run your molecule, it may help you.