PAPER
2-Aryl-1-arylmethyl-1H-benzimidazoles and 2,4,5-Triaryl-1H-imidazoles
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1-(4-Nitrobenzyl)-2-(4-nitrophenyl)-1H-benzimidazole (3h)
MS (EI, 70 eV): m/z = 312 [M + H]+.
White solid; mp 189–191 °C; HPLC purity: 98.3%.
2-[4-(Dimethylamino)phenyl]-4,5-diphenyl-1H-imidazole (6f)
Off-white solid; mp 259 –260 °C.
1H NMR (400 MHz, CDCl3): d = 2.9 (s, 6 H), 7.1 (d, J = 8.2 Hz, 2
H), 7.4–7.55 (m, 4 H), 7.65–7.7 (m, 2 H), 7.8–7.95 (m, 6 H), 8.7 (br
s, 1 H).
1H NMR (400 MHz, CDCl3): d = 5.59 (s, 2 H), 7.19 (dd, J = 8, 1 Hz,
1 H), 7.28 (d, J = 9 Hz, 2 H), 7.35 (td, J = 9, 1 Hz, 1 H), 7.41 (td,
J = 7, 1 Hz, 1 H), 7.84 (d, J = 9 Hz, 2 H), 7.93 (dd, J = 8, 1 Hz, 1
H), 8.24 (d, J = 8 Hz, 2 H), 8.33 (d, J = 9 Hz, 2 H).
MS (EI, 70 eV): m/z = 374 [M + H]+.
MS (EI, 70 eV): m/z = 339 [M + H]+.
1-[4-(Dimethylamino)benzyl]-2-[4-(dimethylamino)phenyl]-
1H-benzimidazole (3i)
White solid; mp 255–256 °C; HPLC purity: 98%.
Acknowledgement
1H NMR (400 MHz, CDCl3): d = 2.86 (s, 6 H), 2.93 (s, 6 H), 5.59
(s, 2 H), 6.70–6.55 (m, 4 H), 6.96 (d, J = 9 Hz, 2 H), 7.70–7.05 (m,
3 H), 7.55 (d, J = 9, 2 Hz, 2 H), 7.73 (d, J = 8 Hz, 1 H).
The authors are thankful to the Head, Department of Chemical
Technology, Dr. Babasaheb Ambedkar Marathwada University,
Aurangabad - 431004 (MS), India for the providing laboratory faci-
lity.
MS (EI, 70 eV): m/z = 370 [M + H]+.
2-(2-Furyl)-1-(2-furylmethyl)-1H-benzimidazole (3j)
White solid; mp 94–95 °C; HPLC purity: 98%.
References
1H NMR (400 MHz, CDCl3): d = 5.64 (s, 2 H), 6.21 (dd, J = 3, 1 Hz,
1 H), 6.26 (dd, J = 3, 2 Hz, 1 H), 6.59 (dd, J = 4, 2 Hz, 1 H), 7.20
(dd, J = 3, 1 Hz, 1 H), 7.31–7.25 (m, 3 H), 7.51–7.44 (m, 1 H), 7.62
(dd, J = 2, 1 Hz, 1 H), 7.82–7.75 (m, 1 H).
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MS (EI, 70 eV): m/z = 264 [M + H]+.
2,4,5-Triaryl-1H-imidazoles 6; General Procedure
A mixture of oxalic acid (10 mol%), NH4OAc (40 mmol), and ben-
zil or benzoin (10 mmol) was dissolved in EtOH–H2O (1:1, 20 mL)
and aromatic aldehyde (12 mmol) was added. The mixture was
heated at 80 °C until completion (TLC). The mixture was cooled to
r.t., poured into ice-water (50 mL) and the solid that precipitated
was collected by filtration, washed with H2O, and dried to give the
2,4,5-triaryl-1H-imidazole.
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R. W. Jr.; Michejda, C. J. J. Med. Chem. 1997, 40, 4199.
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Tetrahedron: Asymmetry 2002, 13, 137.
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Scarborough, R. M. Tetrahedron Lett. 1999, 40, 2665.
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2002, 21, 4350. (b) Ben-alloum, A.; Bakkas, S.; Soufiaoui,
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2,4,5-Triphenyl-1H-imidazole (6a)
Off-white solid; mp 276–277 °C; HPLC purity: 98%.
1H NMR (400 MHz, DMSO): d = 7.55–7.68 (m, 6 H), 7.72–7.75
(m, 3 H), 7.9–7.95 (m, 6 H), 8.8 (br s, 1 H).
MS (EI, 70 eV): m/z = 296 [M + H]+.
2-(4-Chlorophenyl)-4,5-diphenyl-1H-imidazole (6b)
Off-white solid; mp 264–364 °C; HPLC purity: 95.5%.
1H NMR (400 MHz, CDCl3): d = 7.5–7.65 (m, 6 H), 7.68–7.72 (m,
2 H), 7.9–8.0 (m, 6 H), 8.7 (br s, 1 H).
MS (EI, 70 eV): m/z = 330 [M + H]+.
2-(4-Methoxyphenyl)-4,5-diphenyl-1H-imidazole (6c)
(7) (a) Nagata, K.; Itoh, T.; Ishikawa, H.; Ohsawa, A.
Heterocycles 2003, 61, 93. (b) Currini, M.; Epifana, F.;
Montanari, F.; Rosati, O.; Taccone, S. Synlett 2004, 1832.
(8) Wilfred, C. D.; Taylor, R. J. K. Synlett 2004, 1628.
(9) (a) Kim, B. H.; Han, R.; Kim, J. S.; Jun, Y. M.; Baik, W.;
Lee, B. M. Heterocycles 2004, 63, 41. (b) Yang, D. L.;
Fokas, D.; Li, J. Z.; Yu, L. B.; Baldino, C. M. Synthesis
2005, 47.
Off-white solid; mp 241–243 °C; HPLC purity: 96.6%.
1H NMR (400 MHz, CDCl3): d = 3.9 (s, 3 H), 7.32 (d, J = 8.1 Hz, 2
H), 7.5–7.65 (m, 4 H), 7.75 (m, 2 H), 7.85–7.95 (m, 6 H), 8.7 (br s,
1 H).
MS (EI, 70 eV): m/z = 326 [M + H]+.
2-(4-Nitrophenyl)-4,5-diphenyl-1H-imidazole (6d)
(10) (a) Kokare, N. D.; Nagawade, R. R.; Rane, V. P.; Shinde, D.
B. Synthesis 2007, 766. (b) Kotharkar, S. A.; Jadhav, M. R.;
Nagawade, R. R.; Bahekar, S. S.; Shinde, D. B. Lett. Org.
Chem. 2005, 2, 398. (c) Nagawade, R. R.; Khanna, V. V.;
Bhagwat, S. S.; Shinde, D. B. Eur. J. Med. Chem. 2005, 40,
1325. (d) Bahekar, S. S.; Shinde, D. B. Tetrahedron Lett.
2004, 45, 7999. (e) Bahekar, S. S.; Kotharkar, S. A.; Shinde,
D. B. Mendeleev Commun. 2004, 210.
Off-white solid; mp 131–133 °C.
1H NMR (400 MHz, CDCl3): d = 7.5–7.65 (m, 4 H), 7.68–7.72 (m,
4 H), 7.9–8.0 (m, 4 H), 8.25 (d, J = 8.1 Hz, 2 H), 8.9 (br s, 1 H).
MS (EI, 70 eV): m/z = 341 [M + H]+.
2-(4-Hydroxyphenyl)-4,5-diphenyl-1H-imidazole (6e)
Off-white solid; mp 256–257 °C; HPLC purity: 97.1%.
1H NMR (400 MHz, CDCl3): d = 5.3 (br s, 1 H), 7.55–7.60 (m, 6 H),
7.65–7.72 (m, 2 H), 7.9–8.0 (m, 6 H), 8.7 (br s, 1 H).
Synthesis 2007, No. 18, 2829–2834 © Thieme Stuttgart · New York