N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
110
4 13 C NMR
Effect of Substituents in Position 4 on 13 C Chemical Shifts of Monosubstituted
Pyridines (δ in ppm)
Substituent R
C-2
C-3
C-4
–CH 3
0.5
0.7
10.6
–CH 2 CH 3
-0.1
-0.5
16.8
–CH(CH 3 ) 2
0.4
-1.9
21.2
–C(CH 3 ) 3
0.9
-2.6
23.9
–CH=CH 2
0.3
-3.0
8.4
–phenyl
0.4
-2.2
12.2
–F
2.7
-11.9
32.8
–Br
3.0
3.3
-3.2
–I
0.2
9.1
-30.8
–OH*
-9.8
-6.2
45.4
–OCH 3
0.9
-13.9
29.0
–OCOCH 3
1.7
-6.7
23.9
–NH 2
0.7
-13.8
19.3
–NHCH 3
0.5
-15.9
19.8
–N(CH 3 ) 2
0.6
-16.3
19.2
–C– – – N
2.1
2.1
-15.9
–SH
-16.9
5.9
54.3
–SCH 3
0.1
-3.3
14.6
–CHO
1.7
-0.7
5.3
–COCH 3
1.6
-2.7
6.6
–COOCH 3
1.0
-0.8
1.4
–CONH 2
0.4
-0.9
6.2
–Si(CH 3 ) 3
-2.8
2.4
11.9
–Ge(CH 3 ) 3
-1.1
4.4
16.8
–Sn(CH 3 ) 3
-1.1
7.3
16.2
–Pb(CH 3 ) 3
-0.5
9.1
24.6
* Keto form (4-pyridone)
for R: H
δ C 2,6
= 149.8
δ C 3,5
= 123.7
δ C 4
= 135.9
N
R
6
2
5
3
4
C
X
O
N
S
O
||
C
M