257
15 N Chemical Shifts in Monosubstituted Pyridines (δ in ppm relative to
CH 3 NO 2 )
Substituent
in position
solvent
2
3
4
–H
-63.2
-63.2
-63.2
neat
-63.1
-63.1
-63.1
DMSO
-68.7
-68.7
-68.7
CHCl 3
–CH 3
-62.6
-61.7
-70.2
neat
–CH 2 CH 3
-64.0
-61.4 a
-65.5
neat
–CH=CH 2
-71.0
–
-65.1
DMSO
–phenyl
-71.2
-68.9 b
-67.7
DMSO
–F
-104.5
-80.8
-73.0
neat
–Cl
-72.6
-57.8
-67.9
DMSO
–Br
-64.3
-56.7
-67.4
DMSO
–OH
-209 c
-67.4
-222 c
acetone
–OCH 3
-112.1
-60
-86.6
neat
–NH 2
d
-113.8
-63.9
-103.7
DMSO
–CN e
-63.8
-63.7
-52.3
neat
–SH
-187 f
-74
-225 f
acetone
–SCH 3
-79
-64
-77
acetone
–CHO
-60.4
-63.3
-47.8
DMSO
–COCH 3
-65.7 a
–
-51.8
neat
–COOH
-65.4
-64.4
-52.0
DMSO
a in DMSO
b in CDCl 3
c Keto form
d δ NH 2 : 2: -307.3; 3: -325.3; 4: -312.0
e δ CN : 2: -119.5, 4: -118.7
f Thioketo form
6.1 15 N NMR Spectroscopy