13C NMR Number the inequivalent carbons for each of the molecules below. Cinnamaldehyde has been numbered...

 

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13C NMR Number the inequivalent carbons for each of the molecules below. Cinnamaldehyde has been numbered as an exam- ple. Notice that the mono-substituted aromatic ring in cinnamaldehyde possesses some symmetry and therefore the two carbons 5 are equivalent and therefore appear at the same chemical shift value. The same thing is true for car- bons 6. This means that the total number of peaks we would expect to find in the 13C NMR spectrum of cinnamalde- hyde is 7. Notice that because of the symmetry the total number of peaks (7) is less than the total number of carbons in the molecule (9). CH3 H H. CH3 H3C ÓCH3 caryophyllene estragole OCH3 OH eugenol 5 ethyl cinnamate cinnamaldehyde Determine which of the structures above best corresponds to the 13C NMR spectrum of the major component (shown below) based on the number of inequivalent carbons and chemical shift. 13C NMR Spectrum of the Major Component of Clove Oil 00 180 160 140 120 100 80 60 40 20 13C NMR Number the inequivalent carbons for each of the molecules below. Cinnamaldehyde has been numbered as an exam- ple. Notice that the mono-substituted aromatic ring in cinnamaldehyde possesses some symmetry and therefore the two carbons 5 are equivalent and therefore appear at the same chemical shift value. The same thing is true for car- bons 6. This means that the total number of peaks we would expect to find in the 13C NMR spectrum of cinnamalde- hyde is 7. Notice that because of the symmetry the total number of peaks (7) is less than the total number of carbons in the molecule (9). CH3 H H. CH3 H3C ÓCH3 caryophyllene estragole OCH3 OH eugenol 5 ethyl cinnamate cinnamaldehyde Determine which of the structures above best corresponds to the 13C NMR spectrum of the major component (shown below) based on the number of inequivalent carbons and chemical shift. 13C NMR Spectrum of the Major Component of Clove Oil 00 180 160 140 120 100 80 60 40 20

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