Hydrogen Deficiency and Infrared Spectrum

12 Solving a Structural Problem Using Combined 1-D and 2-D Techniques 617 

618 Nuclear Magnetic Resonance Spectroscopy Part Five Advanced NMR Techniques 

The methyl group (Hb) appearing at 1.87 ppm is a doublet of doublets. The coupling between proton Hb and Hg is calculated by subtracting 931.99 from 939.08 Hz, V = 7.1 Hz. Notice that this is the same value that was obtained above for Hg. The average value for the distances in Hertz between the smaller peaks yields V = 1.65 Hz. This value is identical to the one obtained above for Hd. 

Finally, the triplet at about 1.3 ppm is assigned to the methyl group (Ha) split by the neighboring methylene group (Hg). In turn, the quartet at about 4.2 results from the coupling to the neighboring methyl group (Hg). 

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The other vinyl proton (11 ) centered on 5.84 ppm can also be described as a doublet of quartets. In this case, it is much more obvious that it is a doublet of quartets than for the pattern at 

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