[Question from NMRWiki Q&A forum] Downfield carbon paired with a upfield proton
Downfield carbon paired with a upfield proton
Dear sirsI have a natural product whose two carbon resoances are appearinga t 46 and 56 ppm but theirs proton resoanances are appearinga at 0.80 and 0.83 ppm respectively. I am unable to understand how there could be a downfield carbon (oxygenated carbon) is paird up with a upfield proton. I request your expert answer.Thanks in advance.
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nmrlearner
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05-20-2011 09:17 PM
[Question from NMRWiki Q&A forum] How can I calculate a carbon-proton coupling constant for a molecule?
How can I calculate a carbon-proton coupling constant for a molecule?
I'm trying to explain a missing HMBC peak, and having a coupling constant less than 10 Hz would do that nicely. It's a formamidine derivative with a 3 bond correlation N=CHNC The C is a quaternary carbon in a benzene ring. Any help would be appreciated.
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nmrlearner
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02-04-2011 07:12 PM
[NMR paper] Carbon-13 NMR studies of alpha-elastin.
Carbon-13 NMR studies of alpha-elastin.
Related Articles Carbon-13 NMR studies of alpha-elastin.
Ups J Med Sci. 1993;98(1):53-63
Authors: Tarnawski R, Kasperczyk J, Drózdz M
NMR investigations of model protein of elastic fibre is presented. Detailed conformation of alpha-elastin polypeptide chain is discussed by comparison with the conformation of synthetic repeat peptides of elastin. Amino acid composition of alpha-elastin obtained from C-13 NMR spectra correlates with the results of sequencing of tropoelastin.
nmrlearner
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08-21-2010 11:53 PM
Chemical shifts in carbon atoms 13C?
This is a bit confusing for me, so i would like help with understanding this:Explain the order of the chemical shifts of the carbon atoms in the 13C spectra of cyclohexanone and adipic acid.if ur not sure about cyclohexanone and adipic acid, at least explain to me what the "order of chemical shifts in the carbon atoms in 13C" meansThanx!
Carbon-13 NMR
Linear Mode
