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ν, cm–1: 3375 m (NH), 1659 m (C=CAr), 1509 s (C=CAr),
1339 m (С=N), 1126 m, 895 s. 1Н NMR spectrum, δ, ppm:
12.92 br. s (NH, 2Н), 7.29–7.52 m (12H), 7.62–7.71 m
(8H), 8.07 d. d (4H, J = 8.7, 1.9 Hz). 13C NMR spectrum,
δC, ppm: 124.2, 126.9, 127.1, 128.6, 128.9, 130.4, 133.3,
137.7, 148.2. Found, %: C 84.05; H 5.07; N 10.86.
C36H26N4. Calculated, %: C 84.02; H 5.09; N 10.89.
octane was added. The precipitate was filtered off and
dried in air. Fine-crystalline green powder was obtained.
3,6-Bis(4,5-diphenylimidazol-2-yliden)-1,4-
cyclohexadiene (3a). Yield 120 mg (25%), bp 135–137°С
(benzene–octane). IR spectrum, ν, cm–1: 1610 m (C=CAr),
1571 m (C=CAr), 1333 m (С=N), 1290 m, 895 s. 1Н NMR
spectrum (DMSO-d6), δ, ppm: 6.95 d (4H, J = 10.2 Hz),
7.52–7.62 m (12H), 8.07 d. d. d (8H, J = 7.9, 1.7, 1.5 Hz).
13C NMR spectrum (DMSO-d6), δС, ppm: 107.1, 128.2,
129.1, 131.2, 132.1, 133.2, 134.9, 140.1, 159.8. Found, %:
C 84.32; H 4.71; N 10.96. C36H24N4. Calculated, %: C
84.35; H 4.72; N 10.93.
1,4-Bis(4,5-diphenylimidazol-2-yl)-2-bromo-
benzene (2b). Yield 350 mg (84%), bp > 300°С
(decomp.). IR spectrum, ν, cm–1: 3360 m (NH), 1662 m
(C=CAr), 1504 s (C=CAr), 1343 m (С=N), 1130 m, 894 s,
1
698 s (С–Br). Н NMR spectrum, δ, ppm: 12.71 br. s
(NH, 2Н), 7.45–7.64 m (12H), 7.78 d. d (1H, J = 8.5,
1.9 Hz), 7.83–7.92 m (4H), 7.95–8.02 m (3H), 8.08 d. d
(1H, J = 1.9, 0.4 Hz). 13C NMR spectrum, δC, ppm: 122.7,
124.2, 126.3, 126.8, 126.9, 127.1, 127.8, 128.6, 129.0,
130.4, 130.7, 133.3, 137.7, 148.2. Found, %: C 72.66;
H 4.24; N 9.46. C36H25BrN4. Calculated, %: C 72.85; H
4.25; N 9.44.
3,6-Bis(4,5-dyphenylimidazol-2-yliden2)-2-bromo-
1,4-cyclohexadiene (3b). Yield 140 mg (23.6%), bp 157–
158°С (benzene–octane). IR spectrum, ν, cm–1: 1604 m
(C=CAr), 1566 m (C=CAr), 1326 m (С=N), 1280 m, 894 s,
1
694 s (С–Br). Н NMR spectrum (DMSO-d6), δ, ppm:
7.51–7.58 m (4H), 7.58–7.68 m (8H), 7.78–7.85 m (4H),
13
7.93–8.04 m (2H), 8.12 s (1Н), 8.20–8.26 m (4H). C
1,4-Bis(4,5-dyhenylimidazol-2-yl)-2,5-di-
brombenzene (2c). Yield 330 mg (70%), bp > 300°С
(decomp.). IR spectrum, ν, cm–1: 3325 m (NH), 1672 s
(C=CAr), 1594 m (C=CAr), 1344 m (С=N), 1284 s, 694 s
NMR spectrum (DMSO-d6), δС, ppm: 108.1, 114.2, 121.4,
127.2, 128.7, 128.9, 129.2, 132.2, 133.2, 134.9, 150.6,
158.9. Found, %: C 73.12; H 3.91; N 9.46. C36H23BrN4.
Calculated, %: C 73.10; H 3.92; N 9.47.
1
(С–Br). Н NMR spectrum (DMSO-d6), δ, ppm:
3,6-Bis(4,5-diphenylimidazol-2-yliden)2,5-dibromo-
1,4-cyclohexadiene (3c). Yield 270 mg (30.2%), bp 172–
174°С (benzene–octane). IR spectrum, ν, cm–1: 1609 m
(C=CAr), 1570 m (C=CAr), 1333 m (С=N), 1282 m, 896 s,
12.75 br. s (NH, 2Н), 7.45–7.63 m (12H), 7.87 d. d. d
(4H, J = 7.1, 2.0, 1.5 Hz), 7.93 d. d. d (4H, J = 7.7, 1.7,
1.5 Hz), 8.08 d (2H, J = 0.4 Hz). 13C NMR spectrum
(CDCl3), δC, ppm: 120.7, 124.2, 126.3, 126.9, 128.6,
128.9, 129.2, 130.4, 130.7, 133.3, 137.7, 148.2. Found,
%: C 64.32; H 3.61; N 8.36. C36H24Br2N4. Calculated,
%: C 64.30; H 3.60; N 8.33.
1
699 s (С–Br). Н NMR spectrum (DMSO-d6), δ, ppm:
7.55–7.67 m (12H), 7.78–7.85 m (8H), 8.02 s (2H). 13C
NMR spectrum (DMSO-d6), δC, ppm: 115.2, 120.4,
128.2, 129.2, 129.8, 131.9, 133.0, 133.2, 158.9. Found,
%: C 64.47; H 3.32; N 8.39. C36H22Br2N4. Calculated:
C 64.50; H 3.31; N 8.36.
General procedure for the synthesis of quinones
3a–3c. 100 mL of 20% solution of K3[Fe(CN)6] was
added to a mixture of 12.5 mL of 6% solution of KОН
and a suspension of 1 mmol of compound 2a–2c in
25 mL of dioxane at continuous stirring during 2 h
under argon atmosphere, maintaining temperature of
the reaction mixture at 5–7°С. When first drops of the
K3[Fe(CN)6] solution were added, the reaction mixture
turned purple and then became green. After the addition
of K3[Fe(CN)6], the reaction mixture was stirred under
argon atmosphere at 5–7°C for 30 min; the precipitate was
filtered off, washed with huge amount of water, and dried
in air. Fine-crystalline purple precipitate was obtained.
To remove the unreacted starting component, the product
was dissolved in 50 mL of benzene and separated from
the undissolved residue. The benzene solution was
evaporated in vacuum to 10 mL volume, and 5 mL of
FUNDING
This study was financially supported by the Ministry of
Science and Higher Education of the Russian Federation as
a part of the government task in the field of research (project
no. 4.4566.2017/8.9).
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
REFERENCES
1. Lu, N.-N.,Yoo, S.J., Li, L.-J., Zeng, C.-C., andLittle, R.D.,
Electrochim. Acta, 2014, vol. 142, p. 254.
2. Francke, R. and Little, R.D., J. Am. Chem. Soc.,
2014, vol. 136, p. 427.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 6 2020