CarboxylicAcidsNMRSpectra

[Galen Knight, pHd]

Greetings:

This would have been helpful, probably, if her Yahoo account was still
active and she still needed a probable solution:

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Dear Maria Torres,

I helped a Russian company improve their NMR spectral estimation software.

Beta-alethine was a good example of a molecule capable of 5- and 6-membered
hydrogen bonding in which the molecule doubles back on itself to form a
hydrogen-bonded ring. Their spectral estimation software assignments were
way off on beta-alethine, which I discovered only after doing 2D proton and
carbon NMR. When I suggested an NMR correction to them for hydrogen
bonding, which takes into account the rigidity of the hydrogen-bonded ring,
however, the spectral shifts came out perfectly, and this could be use to
correct the estimated spectra of even much larger and much more complex
molecules that hydrogen-bonded.

One does have to have a good sense of how your 5- and 6-membered ring
structure organization prioritizes in more complex molecules to make it
work. This might be a Godsend to protein NMR if the process of hydrogen-
bonding can be automated to predict, say the secondary and tertiary
structures of proteins based upon their hydrogen-bonded organization,
which could be verified by X-ray crystallography in setting up the
algorithms to greatly improve interpretation in very complex molecules.

'T'would make a very interesting research project if it hasn't already
been done."

Hi guys. I'm stuck on an NMR problem. I see a broad peak at 11ppm,
which I think is a carboxylic acid. I then see 3 overlapping peaks,
the highest is at 2.6, the smallest is at 2.55, and a medium height
one at 2.69. The final peak is a very tall one at 2.1.If anyone can
suggest some good hints or starting places, I'd really appreciate
it. ALl the structures I've drawn out get close, but don't quite hit
the mark. Thanks,
Maria