N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
198
5 1 H NMR
S
Effect of Substituents on the 1 H Chemical Shifts of Monosubstituted Thiophenes (in ppm)
H 3
H 4
H 5
H 2
H 4
H 5
Substituent
in position 2 or 5
in position 3 or 4
Z 23
Z 54
Z 24
Z 53
Z 25
Z 52
Z 32
Z 45
Z 34
Z 43
Z 35
Z 42
–CH 3
-0.34 -0.20 -0.24
-0.45 -0.22 -0.15
–C– – – C
0.02 -0.29 -0.23
–phenyl
0.11 0.28 0.05
–2-thienyl
0.08 -0.09 -0.11
–2-pyridyl
0.48 0.01 0.06
–F
-0.78 -0.54 -0.86
-0.80 -0.40 -0.31
–Cl
-0.30 -0.35 -0.39
-0.25 -0.17 -0.09
–Br
-0.05 -0.23 -0.10
-0.23 -0.21 -0.21
–I
0.11 -0.34 -0.01
-0.05 -0.13 -0.30
–OH*
-0.85 0.44 -3.21
–OCH 3
-0.93 -0.41 -0.82
-1.10 -0.36 -0.17
–NH 2
-1.08 -0.58 -0.96
-1.36 -0.66 -0.36
–NO 2
0.69 -0.16 0.19
0.84 0.47 -0.08
–C– – – N
0.34 -0.13 0.17
0.52 0.07 0.04
–SH
-0.13 -0.33 -0.18
-0.33 -0.33 -0.21
–SCH 3
-0.16 -0.31 -0.16
-0.44 -0.23 -0.14
–S(O) 2 CH 3
0.90 0.07 0.68
0.85 0.35 0.35
–S(O) 2 Cl
0.60 -0.07 0.34
–SCN
0.17 -0.18 0.17
0.14 -0.08 -0.06
–CHO
0.69 0.13 0.47
0.81 0.44 0.06
–COCH 3
0.60 0.03 0.32
0.74 0.45 0.01
–CO–phenyl
0.55 0.06 0.40
–COOH
0.67 -0.05 0.29
0.93 0.48 0.03
–COOCH 3
0.70 0.00 0.22
0.67 0.34 -0.16
–CONHNH 2
0.63 0.04 0.41
-7.31
-7.09 -7.31
–COCl
0.75 -0.07 0.33
0.94
0.37 -0.08
* Keto form
δ H-2 = 7.31 + Z i2
δ H-3 = 7.09 + Z i3
δ H-4 = 7.09 + Z i4
δ H-5 = 7.31 + Z i5
C
X
O
N
S
O
||
C
2
3
5
4
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
198
5 1 H NMR
S
Effect of Substituents on the 1 H Chemical Shifts of Monosubstituted Thiophenes (in ppm)
H 3
H 4
H 5
H 2
H 4
H 5
Substituent
in position 2 or 5
in position 3 or 4
Z 23
Z 54
Z 24
Z 53
Z 25
Z 52
Z 32
Z 45
Z 34
Z 43
Z 35
Z 42
–CH 3
-0.34 -0.20 -0.24
-0.45 -0.22 -0.15
–C– – – C
0.02 -0.29 -0.23
–phenyl
0.11 0.28 0.05
–2-thienyl
0.08 -0.09 -0.11
–2-pyridyl
0.48 0.01 0.06
–F
-0.78 -0.54 -0.86
-0.80 -0.40 -0.31
–Cl
-0.30 -0.35 -0.39
-0.25 -0.17 -0.09
–Br
-0.05 -0.23 -0.10
-0.23 -0.21 -0.21
–I
0.11 -0.34 -0.01
-0.05 -0.13 -0.30
–OH*
-0.85 0.44 -3.21
–OCH 3
-0.93 -0.41 -0.82
-1.10 -0.36 -0.17
–NH 2
-1.08 -0.58 -0.96
-1.36 -0.66 -0.36
–NO 2
0.69 -0.16 0.19
0.84 0.47 -0.08
–C– – – N
0.34 -0.13 0.17
0.52 0.07 0.04
–SH
-0.13 -0.33 -0.18
-0.33 -0.33 -0.21
–SCH 3
-0.16 -0.31 -0.16
-0.44 -0.23 -0.14
–S(O) 2 CH 3
0.90 0.07 0.68
0.85 0.35 0.35
–S(O) 2 Cl
0.60 -0.07 0.34
–SCN
0.17 -0.18 0.17
0.14 -0.08 -0.06
–CHO
0.69 0.13 0.47
0.81 0.44 0.06
–COCH 3
0.60 0.03 0.32
0.74 0.45 0.01
–CO–phenyl
0.55 0.06 0.40
–COOH
0.67 -0.05 0.29
0.93 0.48 0.03
–COOCH 3
0.70 0.00 0.22
0.67 0.34 -0.16
–CONHNH 2
0.63 0.04 0.41
-7.31
-7.09 -7.31
–COCl
0.75 -0.07 0.33
0.94
0.37 -0.08
* Keto form
δ H-2 = 7.31 + Z i2
δ H-3 = 7.09 + Z i3
δ H-4 = 7.09 + Z i4
δ H-5 = 7.31 + Z i5
C
X
O
N
S
O
||
C
2
3
5
4