N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
196
5 1 H NMR
Effect of Substituents on the 1 H Chemical Shifts of Monosubstituted Furans
(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
-0.45 -0.15 -0.17
-0.25 -0.17 -0.12
–CH 2 CH 3
-0.42 -0.12 -0.14
–CH 2 OH
-0.12 -0.07 -0.05
-0.07 0.00 -0.06
–CH 2 SH
-0.22 -0.09 -0.09
–CH 2 SCH 3
-0.21 -0.09 -0.08
–CH=CHCOCH 3 (trans) 0.29 0.11 0.08
–Br
-0.23 -0.17 -0.17
–I
0.04 -0.21 -0.05
-0.17 -0.04 -0.26
–OCH 3
-1.26 -0.14 -0.57
-0.50 -0.36 -0.41
–NO 2
1.13 0.47 0.47
–C– – – N
0.48 -0.02 -0.04
0.41 0.14 -0.06
–SCH 3
0.05 0.01 0.13
-0.22 -0.13 -0.19
–SCN
0.32 -0.02 0.06
0.15 0.11 -0.01
–CHO
0.92 0.25 0.31
0.92 0.47 0.19
–COCH 3
0.81 0.16 0.18
0.42 0.28 -0.16
–COCO–2-furyl
1.26 0.27 0.37
–COOH
0.97 0.19 0.24
0.70 0.40 0.03
–COOCH 3
0.81 0.14 0.18
0.60 0.37 0.01
–COCl
1.14 0.32 0.46
–P(–x-furyl) 2
0.25 a -0.12 a 0.03 a
-0.16 b -0.10 b -0.09 b
–P(O)(–x-furyl) 2
0.76 a 0.15 a 0.30 a
0.14 b 0.19 b 0.31 b
–P(S)(–x-furyl) 2
0.77 a 0.12 a 0.27 a
0.10 b 0.18 b 0.30 b
–P + (CH 3 )(2-furyl) 2 I –
1.53 0.49 0.77
–HgCl
-0.09 0.02 0.25
–Hg–x-furyl
0.18 a 0.24 a 0.47 a
-0.10 b 0.10 b -0.10 b
a x = 2, b x = 3
δ H-2 = 7.42 + Z i2
δ H-3 = 6.38 + Z i3
δ H-4 = 6.38 + Z i4
δ H-5 = 7.42 + Z i5
O
2
3
5
4
C
X
O
N
S
O
||
C
M
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
196
5 1 H NMR
Effect of Substituents on the 1 H Chemical Shifts of Monosubstituted Furans
(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
-0.45 -0.15 -0.17
-0.25 -0.17 -0.12
–CH 2 CH 3
-0.42 -0.12 -0.14
–CH 2 OH
-0.12 -0.07 -0.05
-0.07 0.00 -0.06
–CH 2 SH
-0.22 -0.09 -0.09
–CH 2 SCH 3
-0.21 -0.09 -0.08
–CH=CHCOCH 3 (trans) 0.29 0.11 0.08
–Br
-0.23 -0.17 -0.17
–I
0.04 -0.21 -0.05
-0.17 -0.04 -0.26
–OCH 3
-1.26 -0.14 -0.57
-0.50 -0.36 -0.41
–NO 2
1.13 0.47 0.47
–C– – – N
0.48 -0.02 -0.04
0.41 0.14 -0.06
–SCH 3
0.05 0.01 0.13
-0.22 -0.13 -0.19
–SCN
0.32 -0.02 0.06
0.15 0.11 -0.01
–CHO
0.92 0.25 0.31
0.92 0.47 0.19
–COCH 3
0.81 0.16 0.18
0.42 0.28 -0.16
–COCO–2-furyl
1.26 0.27 0.37
–COOH
0.97 0.19 0.24
0.70 0.40 0.03
–COOCH 3
0.81 0.14 0.18
0.60 0.37 0.01
–COCl
1.14 0.32 0.46
–P(–x-furyl) 2
0.25 a -0.12 a 0.03 a
-0.16 b -0.10 b -0.09 b
–P(O)(–x-furyl) 2
0.76 a 0.15 a 0.30 a
0.14 b 0.19 b 0.31 b
–P(S)(–x-furyl) 2
0.77 a 0.12 a 0.27 a
0.10 b 0.18 b 0.30 b
–P + (CH 3 )(2-furyl) 2 I –
1.53 0.49 0.77
–HgCl
-0.09 0.02 0.25
–Hg–x-furyl
0.18 a 0.24 a 0.47 a
-0.10 b 0.10 b -0.10 b
a x = 2, b x = 3
δ H-2 = 7.42 + Z i2
δ H-3 = 6.38 + Z i3
δ H-4 = 6.38 + Z i4
δ H-5 = 7.42 + Z i5
O
2
3
5
4
C
X
O
N
S
O
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C
M