HNMR & CNMR infirmation to identify a compound

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SUMMARY

The discussion focuses on identifying a compound with the molecular formula C7H10O2 using HNMR and 13C NMR data. Key signals include a singlet at 1.16 ppm (3H) indicating a methyl group adjacent to a carbonyl, and a singlet at 2.21 ppm (2H) corresponding to an acetyl group. The 13C NMR reveals a carbonyl at 216.25 ppm and a C-O signal at 52.57 ppm, suggesting the presence of either a methyl ketone or an acetate group. The analysis highlights the importance of understanding splitting patterns and the implications of missing data in NMR interpretation.

PREREQUISITES
  • Understanding of HNMR spectroscopy and signal interpretation
  • Knowledge of 13C NMR spectroscopy and chemical shift values
  • Familiarity with functional groups, particularly carbonyls and ethers
  • Experience with structural elucidation techniques in organic chemistry
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  • Research the differences between methyl ketones and acetate groups in organic compounds
  • Learn about the implications of heteronuclear decoupling in 13C NMR spectroscopy
  • Study the significance of chemical shifts in 13C NMR for functional group identification
  • Explore advanced NMR techniques for complex structure elucidation
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Chemists, organic chemistry students, and researchers involved in structural analysis and compound identification using NMR spectroscopy.

FARADAY JR
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I was given a structure C7H10O2 AND i WAS GIVEN THE FOLLOWING INFORMATION
HNMR:
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.
 
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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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