SAMPLE 1H NMR WRITE-UP
OCH 3
O
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
The 1H NMR spectrum clearly shows four sets of signals. Those which appear in the region  7.25 to 8.10 ppm can
be attributed to aromatic hydrogens. The upfield signal at  1.15 ppm is most likely due to alkyl hydrogens. The
third set of signals between  5.65 to 6.75 ppm exhibit olefinic hydrogen characteristics, although it is not too
unusual to observe aromatic hydrogens in this range either. Finally the signals between  3.20 to 5.20 ppm suggest
hydrogens deshielded because of proximity to electronegative groups.
The aromatic signals are consistent with a disubstituted ring. The lack of symmetry in the aromatic signals rules out
a para substitution pattern. The two triplets expected for an ortho-disubstituted ring are not observed in the present
spectrum. A meta-disubstituted ring as shown below is the most plausible arrangement.
HC
HA
HB
HD
The triplet observed at  7.34 ppm can be assigned to H A which is consistent with the fact that it is meta to both of
the electron withdrawing substituents on the ring. HB and HC both exhibit the expected doublets. The coupling
constants, J (HB-HA) and J (HC-HA) are identical as predicted. Finally the signal for HD is observed as a singlet at
lowest field, at  8.40 ppm since it is ortho to both electron withdrawing substituents.
8.4
8.3
8.2
8.1
8.0
7.9
7.8
7.7
7.6
7.5
7.4
7.3
7.2
7.1
In the olefinic region the benzylic methine is observed as a doublet at  6.60 ppm. The coupling constant (J=15 Hz)
is indicative of a trans stereochemistry. The other olefinic signal at  5.68 ppm appears as a doublet of triplets with
two central peaks overlapping, and thus showing a multiplicity of 5.
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
Although the doublet at at  5.05 ppm is somewhat downfield for an oxygen bearing methylene, the further
deshielding can be attributed to the allylic character. The methoxy group hydrogens are observed as a singlet at
 3.20 ppm as predicted.
The remaining quartet and a triplet are suggestive of an ethyl group. The chemical shift of the quartet at  3.50 ppm
is consistent with a methylene - to a carbonyl. Finally, the triplet with the most upfield chemical shift, at  1.05
ppm is characteristic of the methyl group in the propanoyl moiety.