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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[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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Linear Mode
