NEW PHOTOCHROMIC NITROBENZYL PYRIDINE DERIVATIVES
slowly added to the refluxing solution and the mixture was kept
under reflux for 5 h. The reaction mixture was added to a
saturated sodium chloride solution. The organic layer was
separated and the aqueous layer was extracted with dichlor-
omethane. The combined organic layers were dried with sodium
sulfate. The solvent was removed in vacuum and the crude
product was purified by column chromatography.
123.1, 122.9, 122.2 41.0; EI-MS (70 eV, m/z) [M]þ 276.9; CI-MS (m/z)
[M þ H]þ 278.0.
2-(2,4,6-Trinitrobenzyl)phenanthroline (8)
A solution of 1.43 g (7.02 mmol) of 2,4,6-trinitrofluorobenzene (2)
and 1.07 g (7.02 mmol) of dry cesium fluoride in 100 ml of dry
tetrahydrofuran was mixed and stirred under reflux. Then a
mixture of 1.16 g (7.02 mmol) of 2-(triethylsilylmethyl)phenan-
throline (11) in dry tetrahydrofuran was added to the hot solution
and refluxed for 1 h. The reaction was stopped by adding water.
The organic layer was separated with saturated sodium chloride
solution. The aqueous layer was extracted with dichloromethane
and the combined organic layer was dried with sodium sulfate.
The solvent was removed in vacuum and the crude product was
purified by column chromatography on silica gel (deactivated
with cyclohexane/triethylamine, 5:1, eluent: cyclohexane/dichlor-
omethane/tri-ethylamine, 15:15:1, Rf ¼ 0.15). Yield: 1.88 g
(4.63 mmol, 66%); IR (film) 3049 (w), 1603 (w), 1535 (s), 1411
(w), 1342 (s), 1177 (w), 1140 (w), 1076 (w), 935 (w), 900 (m), 850 (s),
808 (w), 776 (w), 734 (s), 721 (s), 698 (w), 882 (w), 622 (w) cmꢀ1; 1H
NMR (600 MHz, CDCl3) d 9.14 (dd, J ¼ 4.3, 1.8 Hz, 1H), 8.99 (s, 2H),
8.20 (m, 2H), 7.77 (d, J ¼ 8.8 Hz, 1H), 7.75 (d, J ¼ 8.8 Hz, 1H), 7.60
(dd, J ¼ 8.0, 4.3 Hz, 1H), 7.39 (d, J ¼ 8.2 Hz, 1H), 5.15 (s, 2H); 13C
NMR (150 MHz, CDCl3) 155.3, 152.3, 150.5, 146.6, 145.9, 137.3,
135.8, 134.3, 129.1, 127.4, 126.8, 126.1, 123.1, 122.7, 121.8, 37.0;
ESI-MS (m/z) [M þ H]þ calculated for C19H11N5O6 þ H 406.0782,
found 406.0758.
2-(2,4,6-Trinitrobenzyl)pyridine (4)
Following the general procedure a boiling mixture of 500 mg
(2.16 mmol) of 2,4,6-trinitrofluorobenzene (2) and 330 mg
(2.16 mmol) of cesium fluoride in 100 ml tetrahydrofuran was
slowly mixed with 360 mg (2.16 mmol) of 2-(trimethylsilylmethyl)-
pyridine (3). The crude product was purified on silica gel
(deactivated with cyclohexane/triethylamine, 5:1, eluent: cyclo-
hexane/dichloromethane/triethylamine, 20:10:1, Rf ¼ 0.29). Yield:
145 mg (0.475 mmol, 22%); IR (film) 3093 (m), 2211 (w), 1588 (m),
1535 (s), 1470 (m), 1431 (m), 1341 (s), 1235 (m), 1149 (m), 1082
(m), 669 (m), 899 (m), 756 (m), 720 (s), 529 (m), 492 (m) cmꢀ1; 1H
NMR (200 MHz, CDCl3): d ¼ 8.89 (s, 2H), 8.31 (ddd, J ¼ 4.7, 1.7,
0.9 Hz, 1H), 7.66 (ddd, J ¼ 7.7, 7.7, 1.8 Hz, 1H), 7.27 (br. d, J ¼ 7.7 Hz,
1H), 7.13 (ddd, J ¼ 7.6, 4.8, 0.9 Hz, 1H), 4.8 (s, 2H); 13C NMR
(125 MHz, CDCl3) 154.9, 152.0, 149.2, 146.1, 137.0, 134.7, 123.0,
122.5, 122.2, 35.2; EI-MS (70 eV, m/z) [M]þ 304.1; CI-MS (m/z)
[M þ H]þ 305.0.
2-(2,4,6-Trinitrobenzyl)quinoline (6)
A mixture of 1.50 g (6.47 mmol) 2,4,6-trinitrofluorobenzene (2)
and 980 mg (6.47 mmol) of cesium fluoride in 100 ml of
tetrahydrofuran was heated to reflux and 1.39 g (6.47 mmol) of
2-(trimethylsilylmethyl)quinoline (10) was added. The crude
product was purified on silica gel (deactivated with cyclohexane/
triethylamine, 5:1, eluent: cyclohexane/dichloromethane/triethy-
lamine, 20:10:1, Rf ¼ 0.41). Yield: 940 mg (2.65 mmol, 41%); IR
(film) 3104 (w), 2359 (s), 1601 (m), 1535 (s), 1499 (s), 1424 (m),
1338 (s), 1079 (m), 912 (m), 892 (m), 813 (m), 784 (m), 718 (s), 516
(m), 478 (m) cmꢀ1; 1H NMR (500 MHz, CDCl3) d ¼ 8.93 (s, 2H), 8.31
(d, J ¼ 8.4 Hz, 1H), 7.7–7.8 (m, 2H), 7.62 (ddd, J ¼ 8.4, 6.9, 1.4 Hz,
1H), 7.48 (ddd, J ¼ 8.0, 6.9, 1.0 Hz, 1H), 7.38 (d, J ¼ 8.4 Hz, 1H), 4.97
(s, 2H); 13C NMR (125 MHz, CDCl3) 154.6, 152.2, 146.2, 137.3, 134.3,
129.8, 129.4, 128.9, 127.5, 126.9, 126.6, 122.4, 120.7, 35.8; EI-MS
(70 eV, m/z) [M]þ 354.0; CI-MS (m/z) [M þ H]þ 355.1. Anal. Calcd for
C16H10N4O6: C, 54.24; H, 2.85; N, 18.81. Found: C, 55.08; H, 3.43; N,
15.10.
Acknowledgements
We gratefully acknowledge the financial support by the Deutsche
Forschungsgemeinschaft via SFB 677.
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