R. Ranjbar-Karimi et al. / Journal of Fluorine Chemistry 180 (2015) 222–226
225
4.3. General procedure for reactions between pentafluoropyridine and
3JHH = 8.54 Hz, Ar–H), 7.03 (1H, m, Ar–H), 6.29 (1H, s, NH). 13C NMR
(75 MHz, CDCl3): dc 156 (d, JCF = 246.9 Hz, Ar–CF), 144.3 (dm,
1
N-aryl formamides
1JCF = 234 Hz, C-2,6), 134.7 (s, Ar–C), 133.8 (m, C-4), 132.5 (dm,
1JCF = 234 Hz, C-3,5), 124.8 (s, Ar–CH), 122.3 (d, Ar–C), 117.1 (s, Ar–
CH), 116.8 (s, Ar–CH). 19F NMR (282 MHz, CDCl3): dF ꢀ91.54 (m, 2F,
F-2,6), ꢀ118.35 (1F, Ar–CF), ꢀ155.68 (m, 2F, F-3,5).
Potassium carbonate (1.5 mmol) was added to a solution of
formamide 3 (1 mmol) in dry THF (5 ml) and the mixture was
stirred at room temperature for 30 min. Then, pentafluoropyridine
4 (1 mmol) was added and the resulting solution was refluxed at
70 8C for 20 h. The reaction mixture was poured on 10 ml water
and extracted with ethylacetate (3 ꢁ 8 ml), then dried with MgSO4
and solvent evaporated. The product was obtained after purifica-
tion with column chromatography.
4.3.6. 2,3,5,6-Tetrafluoro-N-(4-fluoro-3-nitrophenyl)pyridin-4-
amine (5f)
62%; Yellow solid; mp: 103–106 8C (found: C, 43.4; H, 1.4; N,
13.7. C11H4F5N3O2 requires: C, 43.3; H, 1.3; N, 13.8%). IR (KBr):
n
3336.6 (NH) cmꢀ1 1H NMR (300 MHz, CDCl3): dH 9.85 (1H, s,
.
3
4.3.1. 2,3,5,6-Tetrafluoropyridin-4-yl-N-(4-
methoxyphenyl)formimidate (5a)
NH), 7.21 (1H, m, Ar–H), 7.15 (1H, d, JHH = 8.54 Hz, Ar–H), 7.03
(1H, m, Ar–H). 13C NMR (75 MHz, CDCl3): dc 148.1 (s, Ar–C),
1
30%; Brown oil (found: C, 52.1; H, 2.6; N, 9.4. C13H8F4N2O2
requires: C, 52.0; H, 2.7; N, 9.3%). 1H NMR (300 MHz, CDCl3): dH
8.51 (1H, s, alkene–CH), 7.21 (2H, d, 3JHH = 8.85 Hz, Ar–H), 6.98 (2H,
143.6 (dm, JCF = 234.2 Hz, C-2,6), 141.1 (s–Ar–C), 133.8 (dm,
1JCF = 251.1 Hz, C-3,5), 133.3 (m, C-4), 124.8 (s, Ar–CH), 122.3 (d,
Ar–C), 117.1 (s, Ar–CH), 114.2 (s, Ar–CH). 19F NMR (282 MHz,
CDCl3): dF ꢀ90.64 (m, 2F, F-2,6), ꢀ118.35 (1F, Ar–CF), ꢀ153.12
(m, 2F, F-3,5).
3
d, JHH = 8.91 Hz, Ar–H), 3.85 (3H, s, OCH3). 13C NMR (75 MHz,
CDCl3): dc 160.9 (s, alkene–CH), 159.9 (s, Ar–C), 143.7 (dm,
1JCF = 232.5 Hz, C-2,6), 141 (m, C-4), 135 (dm, 1JCF = 252 Hz, C-3,5),
130.6 (s, Ar–C), 127 (s, Ar–CH), 115.3 (s, Ar–CH), 55.6 (s, OCH3). 19
F
4.3.7. 2,3,5,6-Tetrafluoro-N-(2-(trifluoromethyl)phenyl)pyridin-4-
amine (5g)
NMR (282 MHz, CDCl3): dF ꢀ87.1 (m, 2F, F-2,6), ꢀ143.5 (m, 2F, F-
3,5).
33%; Brown oil (found: C, 46.3; H, 1.5; N, 9.1. C12H5F7N2
requires: C, 46.5; H, 1.6; N, 9.0%). IR (KBr):
n
3430.2 (NH) cmꢀ1. 1H
4.3.2. 2,3,5,6-Tetrafluoropyridin-4-yl-N-(4-
methylphenyl)formimidate (5b)
NMR (300 MHz, CDCl3): d
H 7.71 (1H, d, 3JHH = 7.81 Hz, Ar–H), 7.58
(1H, t, 3JHH = 7.74 Hz, Ar–H), 7.36 (1H, t, 3JHH = 7.68 Hz, Ar–H), 7.22
3
30%; Brown oil (found: C, 55.0; H, 2.7; N, 9.8. C13H8F4N2O
(1H, d, JHH = 8 Hz, Ar–H), 6.41 (s, 1H, NH). 13C NMR (75 MHz,
1
requires: C, 54.9; H, 2.8; N, 9.9%) 1H NMR (300 MHz, CDCl3):
d
H 8.56
CDCl3): dc 143 (dm, JCF = 234.2 Hz, C-2,6), 136.3 (s, Ar–C), 133.9
(1H, s, alkene–CH), 8.02 (1H, s, CH), 7.27 (2H, d, 3JHH = 8.12 Hz, Ar–
H), 7.12 (2H, d, 3JHH = 8.25 Hz, Ar–H), 2.96 (3H, s, CH3), 2.88 (3H, s,
(m, C-4), 132.8 (s, Ar–CH), 132.6 (dm, 1JCF = 255 Hz, C-3,5), 126.7 (s,
Ar–CH), 125.8 (s, Ar–CH), 124.2 (s, Ar–CH), 125.2 (q,
1JCF = 271.2 Hz, CF3). 19F NMR (282 MHz, CDCl3): dF ꢀ61.34 (3F,
s, CF3), ꢀ91.55 (m, 2F, F-2,6), ꢀ155.45 (m, 2F, F-3,5).
CH3). 13C NMR (75 MHz, CDCl3):
dc 162.5 (s, alkene–CH), 160.6 (s,
alkene–CH), 143.8 (dm, 1JCF = 232.5 Hz, C-2,6), 140.5 (m, C-4), 139
(s, Ar–C), 135.4 (dm, 1JCF = 255 Hz, C-3,5), 135.5 (s, Ar–C), 130.8 (s,
Ar–CH), 129.6 (s, Ar–CH), 124.6 (s, Ar–CH), 122.3 (s, Ar–CH), 21,
21.1 (s, CH3). 19F NMR (282 MHz, CDCl3): dF ꢀ88.3 (m, 2F, F-2,6),
ꢀ143.3 (m, 2F, F-3,5).
4.3.8. 2,3,5,6-Tetrafluoro-N-(3-(trifluoromethyl)phenyl)pyridin-4-
amine (5h)
45%; Brown oil (found: C, 46.4; H, 1.7; N, 9.0. C12H5F7N2
requires: C, 46.5; H, 1.6; N, 9.0%). IR (KBr):
NMR (300 MHz, CDCl3): H 7.43 (1H, t, J = 7.6 Hz, Ar–H), 7.26 (1H, d,
n
3254.6 (NH) cmꢀ1. 1H
4.3.3. 2,3,5,6-Tetrafluoro-N-(3-nitrophenyl)pyridin-4-amine (5c)
53%; Yellow solid; mp: 139–142 8C (found: C, 46.0; H, 1.7; N,
d
3
3JHH = 8.1 Hz, Ar–H), 7.25 (1H, s, Ar–H), 7.12 (1H, d, JHH = 7.5 Hz,
Ar–H), 6.41 (s, 1H, NH). 13C NMR (75 MHz, CDCl3): 143 (dm,
1JCF = 234.2 Hz, C-2,6), 136.3 (s, Ar–C), 133.9 (m, C-4), 132.8 (s, Ar–
CH), 132.6 (dm, 1JCF = 255 Hz, C-3,5), 126.7 (s, Ar–CH), 125.8 (s, Ar–
14.4. C11H5F4N2O2 requires: C, 46.0; H, 1.8; N, 14.6%). IR (KBr):
n
3353.1 (NH) cmꢀ1. 1H NMR (300 MHz, CDCl3):
d
H 9.85 (1H, s, NH),
3
7.9 (1H, s, Ar–H), 7.9 (1H, d, HHH = 7.80 Hz, Ar–H), 7.59 (1H, t,
3HHH = 8 Hz, Ar–H), 7.53 (1H, d, HHH = 7.86 Hz, Ar–H). 13C NMR
(75 MHz, CDCl3): dc 148.1 (s, Ar–C), 143.6 (dm, JCF = 234.2 Hz, C-
CH), 124.2 (s, Ar–CH), 125.2 (q, JCF = 271.2 Hz, CF3). 19F NMR
3
1
1
(282 MHz, CDCl3): dF ꢀ61.34 (3F, s, CF3), ꢀ91.55 (m, 2F, F-2,6),
ꢀ155.45 (m, 2F, F-3,5).
2,6), 141.1 (s–Ar–C), 133.8 (dm, 1JCF = 251.1 Hz, C-3,5), 133.3 (m, C-
4), 130 (s, Ar–CH), 126 (s, Ar–CH), 117.8 (s, Ar–CH), 114.2 (s, Ar–
CH). 19F NMR (282 MHz, CDCl3): dF ꢀ90.64 (m, 2F, F-2,6), ꢀ153.12
(m, 2F, F-3,5).
4.3.9. 2,3,5,6-Tetrafluoropyridin-4-yl-N-(4-
chlorophenyl)formimidate (5i)
15%; Brown oil (found: C, 47.2; H, 1.4; N, 9.1. C12H5ClF4N2O
requires: C, 47.3; H, 1.6; N, 9.2%). 1H NMR (300 MHz, CDCl3): dH
4.3.4. 2,3,5,6-Tetrafluoro-N-(2,4-dibromophenyl)pyridin-4-amine
(5d)
3
8.58 (1H, s, alkene–CH), 7.34 (2H, d, JHH = 8.75 Hz, Ar–H),, 7.06
45%; Brown oil (found: C, 32.8; H, 1.0; N, 6.9. C11H4Br2F4N2
(2H, d, 3JHH = 8.49 Hz, Ar–H), 13C NMR (75 MHz, CDCl3):
d
c 160.1 (s,
1
requires: C, 33.0; H, 1.0; N, 7.0%) IR (KBr):
n
3393.6 (NH) cmꢀ1. 1H
alkene–CH), 144.2 (dm, JCF = 234.5 Hz, C-2,6), 136.7 (s, Ar–C),
136.5 (m, C-4), 132.7 (dm, 1JCF = 251.6 Hz, C-3,5), 130.5 (s, Ar–CH),
129.2 (s, Ar–CH), 125.8 (s, Ar–C). 19F NMR (282 MHz, CDCl3): dF
ꢀ87.62 (m, 2F, F-2,6), ꢀ143.12 (m, 2F, F-3,5).
NMR (300 MHz, CDCl3): dH 7.89 (1H, s, Ar–H), 7.60 (1H, d,
3JHH = 8.31 Hz, Ar–H), 7.23 (1H, d, 3JHH = 8.21 Hz, Ar–H), 6.40 (1H, s,
1
NH). 13C NMR (75 MHz, CDCl3): dc 143.8 (dm, JCF = 230.1 Hz, C-
1
2,6), 139.7 (m, C-4), 137 (s, Ar–C), 134.7 (dm, JCF = 255.2 Hz, C-
3,5), 132.3 (s, Ar–CH), 130.8 (s, Ar–CH), 122.6 (s, Ar–CH), 118.3 (s,
Ar–C), 123.3 (s, Ar–C). 19F NMR (282 MHz, CDCl3): dF ꢀ91.28 (m, 2F,
F-2,6), ꢀ154.17 (m, 2F, F-3,5).
4.3.10. 2,3,5,6-Tetrafluoro-N-(4-chlorophenyl)pyridin-4-amine (5i0)
40%; Brown oil (found: C, 47.7; H, 1.7; N, 10.2. C11H5ClF4N2
requires: C, 47.8; H, 1.8; N, 10.1%), IR (KBr):
NMR (300 MHz, CDCl3):
H 7.47 (2H, d, 3JHH = 8.64 Hz, Ar–H), 7.19
(2H, d, JHH = 8.59 Hz, Ar–H), 6.36 (s, 1H, NH). 13C NMR (75 MHz,
CDCl3):
c 144.2 (dm, 1JCF = 234.5 Hz, C-2,6), 136.5 (m, C-4), 136.5
n
3323.2 (NH) cmꢀ1. 1H
d
3
4.3.5. 2,3,5,6-Tetrafluoro-N-(3-chloro-4-fluorophenyl)pyridin-4-
amine (5e)
d
25%; Brown oil (found: C, 54.6; H, 1.3; N, 9.5. C11H4ClF5N2
(s, Ar–C), 132.7 (dm, 1JCF = 251.6 Hz, C-3,5), 130.9 (s, Ar–CH), 125.8
(s, Ar–C), 123.2 (s, Ar–CH). 19F NMR (282 MHz, CDCl3): dF ꢀ91.92
(m, 2F, F-2,6), ꢀ155.21 (m, 2F, F-3,5).
requires: C, 44.8; H, 1.4; N, 9.5%). IR (KBr):
NMR (300 MHz, CDCl3): dH 7.21 (1H, m, Ar–H), 7.15 (1H, d,
n
3270.5 (NH) cmꢀ1. 1H