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Homework Help: HNMR & CNMR infirmation to identify a compound

  1. Mar 20, 2012 #1
    I was given a structure C7H10O2 AND i WAS GIVEN THE FOLLOWING INFORMATION
    1.16(3H,SINGLET) - RCH2R
    2.21(2H,SINGLET)- RC=OCH3

    13C NMR:
    216.25(SINGLET)- R-C=O-R
    52.57(SINGLET) -C-O
    34.51 (TRIPLET) RCH2R
    20.22 (QUARTET) RCH3

    i identified all the functional groups in the compound but having a problem putting the structure together so any help I would truly appreciate it.
    Last edited by a moderator: Mar 20, 2012
  2. jcsd
  3. Mar 23, 2012 #2


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    I assume the 13C information is taken from an experiment without heteronuclear decoupling. Generally, 13C is performed with the proton decoupler on which gives only singlet type spectra. I also assume you've transposed the number of hydrogens in the 1H data you have given us.

    You have a methyl group next to a carbonyl carbon which means you either have a methyl ketone or an acetate group in your structure (CH3C=OR, R=O- ). An aldehyde would require that your compound were the trivial compound ethanal which isn't right for the given empirical formula. How would you distinguish between a methyl ketone and an acetate? Where does the ketone carbonyl absorb in the 13C spectrum? How about acetate?

    You have a C-O identified so is it an ether or part of the acetate group? Why wouldn't you observe a splitting pattern for this carbon? Is this carbon tertiary or was the splitting information left out for this bit of information? (I don't know the answer to that) You don't have all of the 1H data or all of the 13C data for this compound. Is the remaining data deliberately omitted to make this more of a challenge for you?
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