N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
220
5 1 H NMR
5.9.5 Imines, Oximes, Hydrazines, Hydrazones, and Azines
1 H Chemical Shifts (δ in ppm)
In aldoximes and ketoximes, the chemical shift difference between syn and anti
protons at the α-CH group, Δδ = δ syn - δ anti , depends on the dihedral angle,
φ H–C–C=N :
CH N
N
OH
N
OH
N
N
N
N
N
N
N
+
N
O
–
N
+
N
O
–
N
+
N
O
–
3.7
3.4
7.92
1.28
1.48
4.16
3.16
8.17
7.50
7.48
7.54
8.30
7.45
7.39
7.51
CH N
H
N
φ
φ
Δδ = δ syn - δ anti
0 o
1
60 o
0
115 o
-0.3
N
H
OH
N
H
OH
N
OH
N
OH
N
OH
3.4
8.40
7.46
7.22
8.43
7.46
7.20
7.89
7.38
6.92
1.83
1.89
2.25
2.23
1.66
1.64
1.86
7.52
1.90
9.9
8.9
6.9
7.0
2.50
2.60
2.30
1.74–1.55
2.22
9.9
9.3
10.18
(in DMSO)
H 3 C–NH–NH 2
2.62 3.21