[dae1991]

I'm identifying an unknown in my lab and all information (bp, derivatives, IR, etc) point to cyclohexylamine.  I now have the NMR which shows a multiplet (integral of 6) at ~1.0-1.2ppm, a pentet (integral of ~4) at 1.8-2.0pp, and a pentet (integral of ~1) at 2.6ppm.  This all corresponds great to the aliphatic carbons, however I have nothing for the amine hydrogens.  From what I recall, amine hydrogens register between 1 and 3 ppm.  Any ideas? 

[rucik5]

Hi.
What I would recommend is maybe to compare your spectra to the ones which could be found here:
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi

Namely:

Or from sigma-aldrich, which is of better quality:
http://www.sigmaaldrich.com/spectra/fnmr/FNMR003233.PDF

I assume there wasn't any deuterium in your sample to facilitate the H/D exchange?

[rcmishra]

Please try a 1H-NMR experiment in DMSO-d6, it will show you the protons for amine, if any. Further a D2O shake experiment would confirm those to be protons attached to a hetero atom, 'N' in your case showing broadening/disappearing of the corresponding peak.

[fledarmus]

Readily exchangeable protons such as amines, hydroxyls, and carboxylic acids can be tough to find in a proton NMR. First question, though, you aren't using deutero-methanol for a solvent, are you? That would definitely exchange your amine protons for deuterium, making them disappear from your proton spectra and (very slightly) increasing the amount of residual CD3OH you see from your CD3OD spectra. Even in d6-DMSO, however, small amounts of water or very high concentrations of your sample can lead to lots of proton transfer, and your peak may broaden out so far that your baseline-leveling software obscures it altogether. Hydrogen bonding and resulting hydrogen exchange processes are very fast on an NMR timescale and may blur your peak into background.