Oxidation of Amines and Azides by using HOF·MeCN
n˜max =3055 (sp2 CÀH), 1557 (NO2), 1352 (NO2), 1511 cmÀ1 (Ar CÀC);
1H NMR (400 MHz, CDCl3): d=7.35 ppm (tt, 3JHF =9.4, 4JHF =7.0 Hz,
Oxidation of aromatic amine derivatives
2
1H; H-6); 13C NMR (126 MHz, CDCl3): d=109.7 (t, JCF =22.5 Hz, C-
Nitrobenzene: Aniline (0.93 g, 10.0 mmol) in acetonitrile (50 mL)
and aqueous acetonitrile (75 mL), after 5 h and distillation, gave ni-
trobenzene (0.75 g, 6.1 mmol, 61%) as a pale yellow oil. B.p. 209–
2108C (lit.[34] 209–2108C); 1H NMR (400 MHz, CDCl3): d=7.55 (tm,
3JHH =7.4 Hz, 2H; 2H-3), 7.70 (tt, 3JHH =7.4, 4JHH =1.2 Hz, 1H; H-4),
8.23 ppm (dd, 3JHH =8.8, 4JHH =1.2 Hz, 2H; 2H-2); 13C NMR
(126 MHz, CDCl3): d=123.7 (C-4), 129.5 (C-3), 134.9 (C-2),
148.4 ppm (C-1); IR: n˜max =3076 (sp2 CÀH), 1518 (NO2), 1343 (NO2),
1478 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=123 (74, [MH]+), 77 (96), 51
(100). These values compare well with the literature data.[34]
2
1
2
6), 131.5 (t, JCF =12.9 Hz, C-3), 140.31 (ddd, JCF =263.1, JCF =17.0,
3JCF =4.8 Hz, C-2), 146.3 ppm (ddd, 1JCF =254.2, 2JCF =11.6, JCF
=
3
5.8 Hz, C-1); 19F NMR (376 MHz, CDCl3): d=À134.8 to À135.0 (m,
2F; F-1), À146.6 to À146.8 ppm (m, 2F; F-2); MS (EI+): m/z (%)=
195 (70, [M]+), 165 (52), 149 (77), 99 (100).
Pentafluoronitrobenzene: Pentafluoroaniline (1.83 g, 10.0 mmol) in
acetonitrile (50 mL) and aqueous acetonitrile (75 mL), after 5 h and
distillation, gave pentafluoronitrobenzene (1.55 g, 7.3 mmol, 73%)
as a pale yellow oil. B.p. 160–1628C, (lit.[38] 160–1618C); 13C NMR
1,4-Difluoro-2-nitrobenzene: 2,5-Difluoroaniline (1.29 g, 10.0 mmol)
in acetonitrile (50 mL) and aqueous acetonitrile (75 mL), after 5 h
and distillation, gave 1,4-difluoro-2-nitrobenzene (0.94 g, 5.9 mmol,
59%) as a yellow oil. B.p. 74–758C, 10 mbar (lit.[35] 74–758C,
1
(126 MHz, CDCl3): d=126.5–127.2 (m, C-6), 137.9 (dm, JCF
=
263.2 Hz, C-1), 141.3 (dm, 1JCF =267.1 Hz, C-2), 144.1 ppm (dtt,
2
3
1JCF =263.5, JCF =13.3, JCF =4.1 Hz, C-3); 19F NMR (376 MHz, CDCl3):
3
3
d=À145.5 (d, JFF =16.6 Hz, 2F; 2F-1), À146.2 (t, JFF =21.4 Hz, 1F;
1
10 mbar); H NMR (400 MHz, CDCl3): d=7.27–7.42 (m, 2H; H-5, H-
3
F-3), À158.0 ppm (t, JFF =19.8 Hz, 2F; 2F-2); IR: n˜max =1557 (NO2),
6), 7.79 ppm (dd, 4JHH =7.6, 5JHH =3.1 Hz, 1H; H-3); 13C NMR
1353 (NO2), 1506 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=213 (34,
2
3
(126 MHz, CDCl3): d=113.0 (dd, JCF =28.3, JCF =2.5 Hz, C-5), 119.8
[MH]+), 183 (18), 167 (24), 117 (90).
2
3
2
3
(dd, JCF =23.5, JCF =8.2 Hz, C-6), 122.8 (dd, JCF =23.9, JCF =8.5 Hz,
C-3), 137.2 (s, C-2), 151.9 (dd, 1JCF =263.3, 4JCF =3.2 Hz, C-4),
157.4 ppm (dd, 1JCF =248.2, 4JCF =3.1 Hz, C-1); 19F NMR (376 MHz,
CDCl3): d=À114.3 to À14.4 (m, 1F; F-1), À122.4 to 122.6 ppm (m,
1F; F-4); IR: n˜max =3088 (sp2 CÀH), 1534 (NO2), 1347 (NO2),
1496 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=159 (75, [M]+), 129 (24), 113
(92), 101 (71), 63 (100). These values compare well with the litera-
ture data.[35]
2,3,5,6-Tetrafluoro-4-nitrobenzonitrile: 4-Amino-2,3,5,6-tetrafluoro-
benzonitrile (2.11 g, 10.0 mmol) in acetonitrile (50 mL) and aqueous
acetonitrile (75 mL), after 5 h and column chromatography on
silica gel by using hexane/ethyl acetate (9:1) as the eluent, gave
2,3,5,6-tetrafluoro-4-nitrobenzonitrile (1.54 g, 7.0 mol, 70%) as col-
ourless crystals. M.p. 76–778C (lit.[39] 79–818C); 13C NMR (126 MHz,
3
CDCl3): d=98.2 (tt, 2JCF =17.0, 3JCF =1.9 Hz, C-1), 105.9 (t, JCF
=
3.4 Hz, CN), 134.1 (t, 2JCF =13.4 Hz, C-4), 140.3 (ddd, 1JCF =266.9,
2,4-Difluoro-1-nitrobenzene: 2,4-Difluoroaniline (1.29 g, 10.0 mmol)
in acetonitrile (50 mL) and aqueous acetonitrile (75 mL), after 5 h
and distillation, gave 2,4,-difluoro-1-nitrobenzene (1.10 g, 6.9 mmol,
69%) as a yellow oil. B.p. 73–748C, 15 mbar (lit.[36] 85–868C);
1H NMR (400 MHz, CDCl3): d=7.00–7.12 (m, 2H; H-3, H-5), 8.12–
8.24 ppm (m, 1H; H-6); 13C NMR (126 MHz, CDCl3): d=106.5 (dd,
2
2JCF =14.9, 3JCF =5.9 Hz, C-2), 147.8 ppm (ddm, 1JCF =266.8, JCF
=
11.7 Hz, C-3); 19F NMR (376 MHz, CDCl3): d=À126.9 to À127.0 (m,
2F; F-3), À142.6 to À142.7 ppm (m, 2F; F-2); IR: n˜max =1553 (NO2),
1346 (NO2), 1493 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=220 (4, [M]+),
190 (2), 174 (14), 124 (44).
2
2
4
2JCF =26.6, JCF =24.3 Hz, C-3), 112.2 (dd, JCF =23.1, JCF =4.1 Hz, C-
1,2,4,5-Tetrafluoro-3-nitro-6-(trifluoromethyl)benzene: 2,3,5,6-Tetra-
fluoro-4-(trifluoromethyl)aniline (1.42 g, 6.0 mmol) in acetonitrile
(30 mL) and aqueous acetonitrile (45 mL), after 180 min and distil-
lation, gave 1,2,4,5-tetrafluoro-3-nitro-6-(trifluoromethyl)benzene
(0.98 g, 3.7 mmol, 62%) as a yellow oil. B.p. 68–698C, 5.0 mbar;
13C NMR (126 MHz, CDCl3): d=113.5 (qt, 2JCF =35.9, 2JCF =12.8 Hz,
3
3
5), 128.2 (dd, JCF =11.0, JCF =1.9 Hz, C-6), 134.1 (s, C-1), 156.7 (dd,
1JCF =267.8, 3JCF =13.2 Hz, C-4), 165.7 ppm (dd, 1JCF =260.2, JCF
3
=
11.2 Hz, C-2); 19F NMR (376 MHz, CDCl3): d=À97.4 to À97.7 (m, 1F;
F-2), À110.8 to À111.0 ppm (m, 1F; F-4); IR: n˜max =3092 (sp2 CÀH),
1530 (NO2), 1345 (NO2), 1493 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=
159 (54, [M]+), 129 (42), 113 (61), 101 (45), 63 (100). These values
compare well with the literature data.[36]
1
2
C-6), 120.2 (qm, JCF =277.2 Hz, CF3), 133.0 (tm, JCF =13.7 Hz, C-3),
140.5 (ddd, 1JCF =265.2, 2JCF =16.3, 3JCF =6.2 Hz, C-1), 144.8 ppm
(dd, 1JCF =267.8, 2JCF =12.7 Hz, C-2); 19F NMR (376 MHz, CDCl3):
1,2,4-Trifluoro-5-nitrobenzene: A solution of 2,4,5-trifluoroaniline
(1.49 g, 10.0 mmol) in acetonitrile (50 mL) and aqueous acetonitrile
(75 mL), after 5 h and distillation, gave 1,2,4-trifluoro-5-nitroben-
zene (1.31 g, 7.4 mmol, 74%) as a pale yellow oil. B.p. 78–798C,
15 mbar (lit.[37] 80–818C, 15 mbar); 1H NMR (400 MHz, CDCl3): d=
2
2
d=À57.0 (t, JFF =22.2 Hz, 3F; CF3), À135.6 (dq, JFF =22.1,
3JFF =10.0 Hz, 2F; 2F-1), À144.1 to À144.3 ppm (m, 2F; 2F-2); IR:
n˜max =1560 (NO2), 1358 (NO2), 1500 cmÀ1 (Ar CÀC); MS (EI+): m/z
(%)=263 (76, [M]+), 233 (4), 217 (74), 167 (46).
3
4
3
1-Bromo-2,3,5,6-tetrafluoro-4-nitrobenzene: 4-Bromo-2,3,5,6-tetra-
fluoroaniline (2.44 g, 10.0 mmol) in acetonitrile (50 mL) and aque-
ous acetonitrile (75 mL), after 5 h and column chromatography on
silica gel by using hexane/ethyl acetate (4:1) as the eluent, gave
1-bromo-2,3,5,6-tetrafluoro-4-nitrobenzene (1.40 g, 5.1 mmol, 51%)
7.21 (td, JHF =9.7, JHF =6.3 Hz, 1H; H-3), 8.01 ppm (dd, JHF =16.5,
4JHF =7.7 Hz, 1H; H-6); 13C NMR (126 MHz, CDCl3): d=108.2 (dd,
2JCF =26.3, JCF =22.1 Hz, C-3), 115.1 (dt, JCF =23.1, JCF =2.3 Hz, C-
6), 133.0 (s, C-5), 145.9 (ddd, JCF =252.0, JCF =13.5, JCF =4.0 Hz, C-
4), 152.1 (ddd, JCF =265.9, JCF =16.5, JCF =3.2 Hz, C-1), 153.8 ppm
(ddd, JCF =263.2, JCF =14.1, JCF =11.0 Hz, C-2); 19F NMR (376 MHz,
CDCl3): d=À116.1 to À116.4 (m, 1F; F-4), À120.6 to À120.9 (m,
1F; F-1), À137.2 to À137.4 ppm (m, 1F; F-2); IR: n˜max 3081 (sp2 CÀ
H), 1508 (Ar CÀC), 1538 (NO2), 1346 cmÀ1 (NO2); MS (EI+): m/z (%)=
177 (50, [M]+), 146 (20), 131 (48), 119 (38), 81 (100). These values
compare well with the literature data.[37]
2
2
3
1
3
4
1
2
4
as yellow crystals. M.p. 53–548C (lit.[18] 50–518C); 13C NMR
1
2
3
2
(126 MHz, CDCl3): d=105.8 (t, 2JCF =22.3 Hz, C-1), 130.0 (t, JCF
=
1
2
3
14.0 Hz, C-4), 140.6 (ddd, JCF =270.8, JCF =21.5, JCF =2.2 Hz, C-2),
145.4 ppm (ddm, 1JCF =255.6, 2JCF =13.8 Hz, C-3); 19F NMR
(376 MHz, CDCl3): d= À128.0 to À128.2 (m, 2F; 2F-3), À144.9 to
À145.0 ppm (m, 2F; 2F-2); IR: n˜max =1548 (NO2), 1349 (NO2),
1489 cmÀ1 (Ar CÀC); MS (EI+): m/z (%)=275 (32, [MH]+, 1ꢁ79Br, 1ꢁ
81Br), 245 (24), 228 (18), 148 (100). These values compare well with
the literature data.[18]
1,2,4,5-Tetrafluoro-3-nitrobenzene: 2,3,5,6-Tetrafluoroaniline (1.65 g,
10.0 mmol) in acetonitrile (50 mL) and aqueous acetonitrile
(75 mL), after 5 h and column chromatography on silica gel by
using hexane/dichloromethane (4:1) as the eluent, gave 1,2,4,5-tet-
rafluoro-3-nitrobenzene (1.19 g, 6.1 mmol, 61%) as a yellow oil. IR:
1,3-Dibromo-2,4,5-trifluoro-6-nitrobenzene: 1,3-Dibromo-2,4,5-tri-
fluoroaniline (3.1 g, 10.0 mmol) in acetonitrile (50 mL) and aqueous
ChemSusChem 2012, 5, 312 – 319
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
317