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Topic: problems with APT spectra  (Read 4468 times)

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Offline kriggy

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problems with APT spectra
« on: March 08, 2016, 11:05:34 AM »
Hi guys, Im trying to asign signals of a compound I made few days ago (to be more exact: figure out the position of nitro group because it could be para to the lactam nitrogen, Im pretty sure my structure is correct but you never know..) Anyway, I got this APT spectrum



Im not realy sure because it is method I never used before so there is my problem:
the signal at 23,52 is the methyl (confirmed by HMQC), therefore signals going down should be CH and CH3 right? Then, the carbonyl carbons that I suspect (no crosspeak in HMQC) to be at 168 and 160 should point to the other direction? Also, shouldnt the DMSO signal point down if it has two CH3 groups?

Offline Babcock_Hall

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Re: problems with APT spectra
« Reply #1 on: March 08, 2016, 12:20:07 PM »
Is this DMSO left over from the reaction scheme, or was d6-DMSO the NMR solvent?

Offline kriggy

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Re: problems with APT spectra
« Reply #2 on: March 08, 2016, 04:18:02 PM »
Its DMSO-d6.
 

Offline Babcock_Hall

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Re: problems with APT spectra
« Reply #3 on: March 08, 2016, 06:39:38 PM »
Deuterium is spin-1, and I am not sure what to expect in this experiment.

Offline kriggy

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Re: problems with APT spectra
« Reply #4 on: March 09, 2016, 10:42:26 AM »
Ok, I did consult it with our NMR specialist and we figured out, that the problem is most likely in the software because when she opened the spectrum in Jeol delta (we have the spectrometer from JEOL) the spectrum showed totaly different.

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