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Interpreting a 1H-13C HMBC spectrum

July 28, 2008

Like a COSY experiment, an HMBC dataset offers many combinations of atom connectivity. The goal for the elucidator is to assess each correlation and narrow down a set of fragments that support the data.

For every correlation in a 1H-13C HMBC spectrum, an elucidator must decide whether a correlation corresponds to a 2J, 3J or 4J coupling (NOTE: this is dependent on what the coupling constant is set to in the HMBC sequence). Below is a structural list for all H to C connections—heteroatoms are not shown in the list for the sake of simplicity. The 2J coupling, outlined with a blue box, the 3J coupling, outlined in a green box, and the 4J coupling, outlined with a purple box, offers 3, 6 and 14 possible combinations, respectively.


6 Replies to “Interpreting a 1H-13C HMBC spectrum”

  1. Dear Arvin,
    I am a student in Brazil. I use ACDLabs and I am a fan of you Blog. Then, I have a question.
    In an HMBC experiment (see image file) of a very small sample of isorhamnetin-3-O-glucoside was only observed a single sign of the correlation between the hydrogens of the methoxyl group (s,4.05) and carbon C-3 ‘(148.29). How can I explain this?
    Thank you in advance.
    Best Regards

    Djalma Menezes de Oliveira
    Natural Products Researcher
    Researcher groups: NEPLAM-UFMG, NUPRONAT-UESB
    Phytochemistry area

  2. Sir,I am having H,C,HMBC,HSQC spectra of a compound isolated from a plant.Would you able to interpret the spectra.with regards,Deepa,

  3. Sir,I am having H,C,HMBC,HSQC spectral data of a molecule isolated from a bacteria.Would you please help to interpret the spectra.with regards


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