Cinnamaldehyde spectra

One further point evident in the cinnamaldehyde spectrum is that the four peaks of the C2 proton signal are not all the same size. The two left-hand peaks are somewhat larger than the two right-hand peaks. Such a size difference occurs whenever coupled nuclei have similar chemical shifts—in this case, 7.49 8 for the C3 proton and 6.73 8 for the C2 proton. The peaks nearer the signal of the coupled partner are always larger, and the peaks farther from the signal of the coupled partner are always smaller. Thus, the... 

To understand the 1H NMR spectrum of trans-cinnamaldehyde, we have to isolate the different parts and look at the signal of each proton individually. 

Active Figure 13.19 The 1H NMR spectrum of frans-cinnamaldehyde. The signal of the proton at C2 (blue) is split into four peaks—a doublet of doublets—-by the two nonequivalent neighboring protons. Sign in arwww.thomsonedu.com to see a simulation based on this figure and to take a short quiz. 

UV spectra of neutral solutions of ALCELL lignins exhibited maximum at 205-210 nm and at 275-281 nm which are characteristic of other lignin preparations. Alkali-neutral difference spectra exhibited three maxima at about 252-254 nm, 296-300 and 363-366 nm which indicate the presence of aromatic hydroxyl, a-conjugated hydroxyls, and conjugated carbonyl groups. The latter includes carbonyl groups in the a-position as well as those in cinnamaldehyde units mentioned above. The alkali-neutral difference spectrum of ALCELL lignins reduced with sodium borohydride shows an almost complete elimination of the peak at 360-366 nm and an increase... 

Ferracyclopentanes [74] and [75] are obtained from the reaction of C2F4 with tetra- or tri-carbonyl(tra s-cinnamaldehyde)iron although the H spectrum shows resonances due to both isomers, the 19F spectrum... 

The UV spectra of cinnamaldehyde and its reaction product (an acetal) are quite different, as shown by Fig. 8.5. The necessity of an acid catalyst must be emphasized. Cinnamaldehyde dissolved in methanol will retain its own spectrum (A in Fig. 8.5) for... 

Figure 8.S. Spectra of 0.0318 mM rm 5-cinnamaldehyde in methanol. (A) Spectrum immediately after the solution was prepared (B) spectrum after the solution had been shaken with Aminex O-150S in the H form. From Ref. [13] with permission.

As a method for the synthesis of cinnamaldehyde (3-phenyl-2-prop)enal), a chemist treated 3-phenyl-2-propen-l-ol with K2Cr207 in sulfuric acid. The product obtained from the reaction gave a signal at 8 164.5 in its NMR spectrum. Alternatively, when the chemist treated 3-phenyl-2-propen-l-ol with PCC in CH2CI2, the NMR spectrum of the product displayed a signal at 8 193.8. (AU other signals in the spectra of both compounds appeared at similar chemical shifts.) (a) Which reaction produced cinnamaldehyde (b) What was the other product ... 

H NMR spectrum of trans-cinnamaldehyde. The signal ofthe proton at C2 (blue) is split into four peaks—a doublet of doublets—by the two nonequivalent neighboring protons. 

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