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Solutions for Nuclear Magnetic Resonance Spectroscopy
CC
C
C C
C C
H
HHHH
H
H
HH H H
H
HOOC CH2 CH2 C
O
O CH
CH3
CH3
H H
H
H
H
H
H
H
HH
CH3 CH CH3
OH
δ 10-12 δ 2.3
δ 4.0
δ 1.1
δ 2.3
(i) (j)
δ 1.3
δ 1.3 δ 1.7
δ 4.5
35 continued
(k) (l)
δ 1.4
δ 2.5δ 7.2
36 a
b
cc a = δ 4.0 (septet, 1H)
b = δ 2.5 (broad singlet, 1H) (rapidly exchanging)
c = δ 1.2 (doublet, 6H)
H
H
H
H
HH
δ 3.0δ 7.2
H
H δ 6-7
37
(a) The chemical shift in ppm would not change: δ 4.00.
At 300 MHz, (4.00 x 10−6) x (300 x 106 Hz) = 1200 Hz
The signal is 1200 Hz downfield from TMS in a 300 MHz spectrum. 
Necessarily, 1200 Hz is exactly 5 times 240 Hz because 300 MHz is 
exactly 5 times 60 MHz. They are directly proportional.
(b) Coupling constants do not change with field strength: J = 7 Hz, regardless of field strength.
(c) At 60 MHz, δ 4.00 = 4.00 ppm = (4.00 x 10−6) x (60 x 106 Hz) = 240 Hz
The signal is 240 Hz downfield from TMS in a 60 MHz spectrum.
CH2H
H H
HH
CH2 O C
O
CH3
38
a
bc d
a = δ 7.2-7.3 (multiplet, 5H)
b = δ 4.3 (triplet, 2H)
c = δ 2.9 (triplet, 2H)
d = δ 2.0 (singlet, 3H)
allylic
benzylic allylic and
benzylic
307