J. Tao et al. / Journal of Fluorine Chemistry 144 (2012) 73–78
77
under vacuum to give trifluoromethanesulfonic acid polyfluor-
4.3. General procedure for the preparation of N-alkyl-40-substituted-
oalkyldiyl ester [33], 1a–1b.
stilbazolium salts 4a–4c
4.2.1. 4-(3,3,4,4-Tetrafluoropyrrolidin-1-yl)benzenamine (2a)
Trifluoromethanesulfonic acid 2,2,3,3,-tretrafluoro-1,4-butane-
dily ester, 1a (2 mmol), p-phenylenediamine (3 mmol), and Et3N
(5 mmol) in 25 mL ethanol were placed in a round-bottomed flask
fitted with a reflux condenser, and heated at reflux for 30 h. After
cooling, theorganicsolvent wasremovedunderreducedpressure, to
the residue was added 50 mL dichloromethane then washed with
water (3 ꢁ 20 mL). The organic layer was dried over anhydrous
Na2SO4. After the solvent was removed, the crude product was
purified by column chromatography. The product was isolated using
dichloromethane–petroleum ether (1:1) as eluent to give 2a.
4-(3,3,4,4-tetrafluoropyrrolidin-1-yl)-N-((pyridin-4-yl) methy-
lene) benzenamine (0.15 mmol, 0.0468 g) and n-alkyl bromide
(0.25 mmol) were heated in 5 mL acetonitrile for 12 h under reflux.
After cooling to room temperature, the solvent was removed under
vacuum to give crude product, which was recrystallized from
ethanol–P.E. (1:5) to yield the compounds 4a–4c in modern yield.
4a: Yield: 43%. 1H NMR (400 MHz, CDCl3)
d: 9.26 (d, J = 6.5 Hz,
2H), 8.85 (s, 1H), 8.48 (d,J = 6.5 Hz,2H), 7.50(d,J = 8.9 Hz, 2H), 6.55 (d,
J = 9.0 Hz, 2H), 4.89 (t, J = 7.4 Hz, 2H), 3.86 (m, 4H), 2.04–1.93 (m, 2H),
1.31–1.10 (m, 22H), 0.83(t, J = 6.8 Hz, 3H). 19F NMR (376 MHz, CDCl3)
d
:ꢀ123.16 to ꢀ123.23 (m, 4F) ppm. MS(ESI)m/z:520.69 [M+]. HR-MS
2a: Yield, 76%, white solid. 1H NMR (400 MHz, CDCl3, TMS)
6.69 (d, J = 8.7 Hz, 2H), 6.42 (d, J = 8.7 Hz, 2H), 3.73 (m, 4H), 3.66–
2.54 (br, 2H) ppm. 19F NMR (376 MHz, CDCl3)
d
:
(EI) Calcd. for [C30H42BrF4N3ꢀBr]+: 520.3302 Found, 520.3309.
4b: Yield: 57.6%. 1H NMR (400 MHz, CDCl3)
d: 9.22 (d, J = 6.4 Hz,
d
: ꢀ123.04 to
2H), 8.89 (s, 1H), 8.50 (d, J = 6.4 Hz, 2H), 7.52 (d, J = 8.8 Hz, 2H), 6.56
(d, J = 8.8 Hz, 2H), 4.87 (t, J = 7.2 Hz, 2H), 3.86 (m, 4H), 2.00 (m, 2H),
ꢀ123.39 (m, 4F) ppm. MS (ESI) m/z: 235.53(M+H+). Anal. Calcd. for
[C10H10F4N2]: C, 51.29; H, 4.30; N, 11.96. Found: C, 50.77; H, 4.48;
N, 11.79.
1.21 (m, 26H), 0.85 (t, J = 6.8 Hz, 3H). 19F NMR (376 MHz, CDCl3)
d:
ꢀ123.13 to ꢀ123.21 (m, 4F) ppm. MS (ESI) m/z: 548.36 [M+]. Anal.
Calcd. for [C32H46BrF4N3ꢂ2H2O]: C, 57.83; H, 7.58; N, 6.32. Found: C,
57.74; H, 7.07; N, 6.51.
4.2.2. 4-(3,3,4,4,5,5,6,6-Octafluoroazepan-1-yl)benzenamine (2b)
Trifluoromethaneulfonic acid 2,2,3,3,4,4,5,5-octafluoro-1,6-
hexanedily ester p-phenylenediamine (3 mmol), and Et3N
(5 mmol) in 25 mL ethanol were placed in a round-bottomed
flask fitted with a reflux condenser, and heated at reflux for 30 h.
After cooling, the organic solvent was removed under reduced
pressure. 50 mL of dichloromethane was added to the residue and
then washed with water (3 ꢁ 20 mL). The organic layer was dried
over anhydrous Na2SO4. After the solvent was removed, the crude
product was purified by silica gel column chromatography [SiO2,
CH2Cl2/PE 3:5, v/v] to give a white solid.
4c: Yield: 48%. 1H NMR (400 MHz, CDCl3)
d: 9.25 (d, J = 6.5 Hz,
2H), 8.85 (s, 1H), 8.48 (d, J = 6.4 Hz, 2H), 7.51 (d, J = 8.9 Hz, 2H), 6.56
(d, J = 8.9 Hz, 2H), 4.89 (t, J = 7.2 Hz, 2H), 3.95–3.74 (m, 4H), 2.21–
1.81 (m, 2H), 1.20 (m, 29H), 0.84 (t, J = 6.9 Hz, 3H). 19F NMR
(376 MHz, CDCl3)
d
: ꢀ123.17 to ꢀ123.24 (m, 4F) ppm MS (ESI) m/z:
576.83[M+]. Anal. Calcd. for [C34H50BrF4N3ꢂ1.5H2O]: C, 59.73; H,
7.81; N, 6.15. Found: C, 59.88; H, 7.72; N, 5.8.
4.4. General procedure for the preparation of N-alkyl-40-substituted-
stilbazolium salts 5a–5c
2b: Yield, 56%. 1H NMR (400 MHz, CDCl3)
2H), 6.64 (d, J = 8.6 Hz, 2H), 3.88 (t, J = 12.7 Hz, 4H), 2.62 (br, 2H).
d: 6.81 (d, J = 8.5 Hz,
4-(3,3,4,4,5,5,6,6-Octafluoroazepan-1-yl)-N-((pyridin-4-
yl)methylene)benzenamine (0.15 mmol, 0.0635 g) and n-alkyl
bromide (0.25 mmol) were heated in 10 mL acetonitrile for 12 h
under reflux. After cooling to room temperature, the solvent was
removed under vacuum to give crude product, which was
recrystallized from ethanol–P.E. (1:10) to give the compounds
5a–5c in modern yield.
5a: Yield: 50%. 1H NMR (400 MHz, CDCl3)
d: 9.11 (d, J = 6.5 Hz,
2H), 8.89 (s, 1H), 8.52 (d, J = 6.5 Hz, 2H), 7.49 (d, J = 9.0, 2H), 6.99 (d,
J = 9.1 Hz, 2H), 4.80 (t, J = 7.3 Hz, 2H), 4.15 (t, J = 12.1 Hz, 4H), 2.07–
1.97 (m, 2H), 1.20 (m, 22H), 0.84 (t, J = 6.8 Hz, 3H). 19F NMR
19F NMR (376 MHz, CDCl3)
d
: ꢀ113.30 (s, 4F), ꢀ128.40 (s, 4F) ppm.
MS (ESI) m/z: 335.58 (M+H+). Anal. Calcd. for [C12H10F8N2]: C,
43.13; H, 3.02; N, 8.38. Found: C, 42.98; H, 3.38; N, 8.07.
4.2.3. 4-(3,3,4,4-Tetrafluoropyrrolidin-1-yl)-N-((pyridin-4-
yl)methylene)benzenamine (3a)
To a solution of 2a (0.2009 g, 0.85 mmol) and pyridine-4-
carbaldehyde (0.1364 g, 1.275 mmol) in 25 mL dichloromethane,
was added anhydrous MgSO4 (16 mmol, 1.636 g), and stirred
overnight at room temperature. The inorganic salt was filtered off.
To the residue was added 50 mL PE and filtered to give yellow solid.
(376 MHz, CDCl3)
d
: ꢀ112.34 (s, 4F), ꢀ128.50 (s, 4F). MS (ESI) m/z:
3a: Yield, 96.54%. 1H NMR (400 MHz, CDCl3)
d
: 8.72 (d,
620.71 [M+]. Anal. Calcd. for [C32H42BrF8N3ꢂ2H2O]: C, 52.18; H,
J = 4.8 Hz, 2H), 8.47 (s, 1H), 7.72 (d, J = 4.7 Hz, 2H), 7.33 (d,
J = 7.5 Hz, 2H), 6.57 (d, J = 8.5 Hz, 2H), 3.86 (m, 4H). 19F NMR
6.29; N, 5.70. Found: C, 52.26; H, 6.18; N, 5.89.
5b: Yield: 51%. 1H NMR (400 MHz, CDCl3)
d: 9.16 (d, J = 6.5 Hz,
(376 MHz, CDCl3)
d
: ꢀ123.04 to ꢀ123.39 (m, 4F) ppm. MS (ESI) m/
2H), 8.93 (s, 1H), 8.53 (d, J = 6.5 Hz, 2H), 7.49 (d, J = 9.0 Hz, 2H), 6.98
(d, J = 9.1 Hz, 2H), 4.82 (t, J = 7.3 Hz, 2H), 4.14 (t, J = 12.1 Hz, 4H),
2.00 (m, 2H), 1.21 (m, 26H), 0.84 (t, J = 6.8 Hz, 3H). 19F NMR
z: 324.65(M+). Anal. Calcd. for [C16H13F4N3ꢂ0.5H2O]: C, 57.83; H,
4.25; N, 12.65. Found: C, 58.00; H, 4.27; N, 12.79.
(376 MHz, CDCl3)
d
: ꢀ112.36 (s, 4F), ꢀ128.51 (s, 4F). MS (ESI) m/z:
4.2.4. 4-(3,3,4,4,5,5,6,6-Octafluoroazepan-1-yl)-N-((pyridin-4-
yl)methylene)benzenamine (3b)
648.78 [M+]. Anal. Calcd. for [C34H46BrF8N3ꢂ1.5H2O]: C, 54.04; H,
6.54; N, 5.56. Found: C, 54.50; H, 6.67; N, 5.39.
To a solution of 2b (0.1671 g, 0.5 mmol) and pyridine-4-
carbaldehyde (0.0802 g, 0.75 mmol) in 25 mL dichloromethane,
was added anhydrous MgSO4 (8 mmol, 0.9844 g), and stirred
overnight at room temperature .The inorganic salt was removed by
filtration. To the residue was added 50 mL PE and filtered to give
yellow solid.
5c: Yield: 53%. 1H NMR (400 MHz, CDCl3)
d: 8.95 (d, J = 6.6 Hz,
2H), 8.81 (s, 1H), 8.48 (d, J = 6.6 Hz, 2H), 7.47 (d, J = 9.0 Hz, 2H), 6.97
(d, J = 9.1 Hz, 2H), 4.71 (t, J = 7.4 Hz, 2H), 4.11 (t, J = 11.9 Hz, 4H),
2.05–1.96 (m, 2H), 1.18 (m, 30H), 0.81 (t, J = 6.8 Hz, 3H). 19F NMR
(376 MHz, CDCl3)
d
: ꢀ112.37 (s, 4F), ꢀ128.53 (s, 4F). MS (ESI) m/z:
676.80 [M+]. Anal. Calcd. for [C36H50BrF8N3ꢂ1.5H2O]: C, 55.17; H,
3b: Yield 94.98%. 1H NMR (400 MHz, CDCl3)
J = 4.3 Hz, 2H), 8.44 (s, 1H), 7.71 (d, J = 5.1 Hz, 2H), 7.27 (d,
J = 8.7 Hz, 2H), 6.96 (d, J = 8.8 Hz, 2 H), 4.08 (t, J = 12.2 Hz, 4H). 19
d
: 8.71 (d,
6.82; N, 5.36. Found: C, 55.24; H, 7.59; N, 5.24.
F
Supporting information
NMR (376 MHz, CDCl3)
d
: ꢀ112.58 (s, 4F), ꢀ128.56 (s, 4F) ppm. MS
(ESI) m/z: 424.57(M+). Anal. Calcd. for [C18H13F8N3ꢂ0.5H2O]: C,
Representative DSC and TGA scans for new salts 4a, 4b, 5a, 5b,
and 5c. Polarized Optical Microscopy data. Crystallographic Data
50.01; H, 3.26; N, 9.72. Found: C, 49.87; H, 3.24; N, 9.51.