N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
108
4 13 C NMR
Effect of Substituents in Position 2 on 13 C Chemical Shifts of Monosubstituted
Pyridines (δ in ppm)
N
R
Substituent R
C-2
C-3
C-4
C-5
C-6
–CH 3
8.6
-0.5
0.3
-3.0
-0.7
–CH 2 CH 3
13.7
-1.7
0.4
-2.8
-0.6
–CH=CH 2
5.9
-1.3
1.1
-2.5
-0.3
–phenyl
7.7
-1.6
0.8
-3.2
0.2
–F
13.9
-14.0
5.4
-2.5
-2.0
–Cl
1.8
0.8
2.8
-1.4
0.0
–Br
-7.5
4.6
2.6
-1.1
0.5
–I
-31.6
11.3
1.7
-0.8
1.0
–OH*
15.5
-3.6
-1.1
-17.0
-8.2
–OCH 3
14.3
-12.7
2.6
-7.1
-2.9
–O–phenyl
13.9
-12.2
3.5
-5.3
-2.0
–OCOCH 3
7.6
-7.3
3.4
-1.8
-1.6
–NH 2
8.4
-15.1
1.8
-9.7
-1.6
–NHCH 3
10.9
-16.2
1.5
-11.3
-1.3
–N(CH 3 ) 2
9.6
-17.9
1.2
-12.3
-1.9
–NHCOCH 3
1.4
-9.8
2.6
-3.9
-2.1
–NO 2
6.9
-5.7
3.9
5.4
-0.8
–C – – – N
-15.8
4.8
1.1
3.2
1.4
–SH
30.4
10.7
2.1
-10.6
-12.1
–SCH 3
10.2
-4.6
0.0
-2.2
-0.5
–S(O)CH 3
16.2
-4.4
2.2
0.9
-0.2
–S(O) 2 CH 3
8.5
-2.6
2.4
3.7
0.3
–CHO
3.0
-2.0
1.2
4.2
0.4
–COCH 3
3.8
-2.1
0.9
3.4
-0.8
–COOH
-3.7
0.0
2.5
4.2
-1.7
–COOCH 3
-1.7
1.5
1.1
3.3
0.0
–CONH 2
-0.3
-1.2
1.4
2.8
-1.5
–Si(CH 3 ) 3
18.6
5.0
-2.0
-1.1
0.3
–Sn(CH 3 ) 3
23.3
7.6
-2.7
-1.7
0.6
–Pb(CH 3 ) 3
33.4
9.2
-2.6
-2.3
1.1
* Keto form (2-pyridone)
for R: H
δ C 2,6
= 149.8
δ C 3,5
= 123.7
δ C 4
= 135.9
2
3
6
4
5
C
X
O
N
S
O
||
C
M