A Modified Procedure for the Synthesis of 1-Arylimidazoles

Article abstract of DOI:10.1055/s-2003-42444

A convenient modified process for the synthesis of 1-aromatic substituted imidazoles is provided. The protocol generally affords better yields of the sterically hindered 1-arylimidazoles.

Full text of DOI:10.1055/s-2003-42444

PAPER
2661
A Modified Procedure for the Synthesis of 1-Arylimidazoles
Synthesis
i
of 1-A
r
n
ylimidazolesgping Liu, Jingbo Chen, Jingfeng Zhao, Yuanhong Zhao, Liang Li, Hongbin Zhang*
School of Pharmacy, Yunnan University, Kunming, Yunnan 650091, P. R. China
Fax +86(871)5035538; E-mail: zhanghb@ynu.edu.cn
Received 27 August 2003
not improve the yield. The reaction was even worse when
butane-2,3-dione, hexane-3,4-dione or benzil were used
instead of glyoxal. After several fruitless variations of the
reaction conditions, we finally found that a two-step pro-
cedure provided acceptable to good yield for the prepara-
tion of 1-aryl substituted imidazoles (Scheme 1). The
reaction was carried out initially in methanol, however
ethanol and n-butanol could also be used as solvents with
improved yield being observed in some cases. This meth-
od could be extended to synthesize 1-alkylimidazoles (en-
tries 13 and 14) that could not be obtained by method
reported in the literature. 7
Abstract: A convenient modified process for the synthesis of 1-ar-
omatic substituted imidazoles is provided. The protocol generally
affords better yields of the sterically hindered 1-arylimidazoles.
Key words: 1-substituted imidazole, 1-arylimidazoles, glyoxal
As an important member of the five-membered ring het-
erocycles, imidazole moiety is present in a wide range of
naturally occurring molecules.1 The biological impor-
tance of the imidazole ring system has made it a common
substructure in numerous synthetic compounds such as
3
fungicides,2 herbicides,2 plant growth regulators and
therapeutic agents.4 Recent advance in green chemistry
and organometallic chemistry have extended the bound-
ary of imidazoles to the synthesis and application of a
large class of imidazoles as ionic liquids5 and imidazole-
related N-heterocyclic carbenes.6 Although the 1-aromatic
substituted imidazoles are important building blocks for
the synthesis of compounds mentioned above, few meth-
ods for the preparation of 1-aromatic substituted imida-
zoles have been reported in the literature.7 The known
protocols are either uneconomic to conduct in large scale7c
(catalyst and ligand are required, as well as a stoichiomet-
ric quantity of 1,10-phenanthroline) or is low in product
yields.7a,b Simple and flexible protocol for the synthesis of
1-aromatic substituted imidazoles are still in need. In this
paper, we report a modified procedure for the synthesis of
these compounds.
35% Formaldehyde
O
25% NH3-H2O, MeOH
NH2
N
+
N
R
70 °C , 5-15 hours
R
O
R = t-Bu, 71% yield
R = Ar, less than 1% of the desired product
30% Glyoxal
Scheme 1 Synthesis of 1-substituted imidazoles
In summary, we have developed a convenient process for
the synthesis of 1-aromatic substituted imidazoles. The
protocol generally provided better yield of the sterically
hindered 1-substituted imidazoles. Since the 1-substituted
imidazoles are important substructures for both ionic liq-
uids and N-hetercyclic carbene ligands, this modified pro-
cedure would find its application towards the synthesis of
substituted imidazoles.
Syntheses of 1-arylimidazoles were initially tested by
treatment of aryl amines with ammonia and glyoxal in ba-
sic condition.8 Although this protocol worked well for the
preparation of 1-alkyl substituted imidazoles, for example
1-tert-butyl-1H-imidazole (71% yield), this procedure un-
1-Arylimidazoles; General Procedure
Substituted aniline (0.1 mmol) in MeOH (50 mL) was treated with
30% aq glyoxal (16.2 mL, 0.1mmol) for 16 h at r.t. A yellowish
mixture was formed. NH4Cl (10.7g, 0.2 mol) was added followed
by 37% aq formaldehyde (16 mL, 0.2 mol). The mixture was diluted
fortunately leads to a complex mixture when applied to with MeOH (400 mL) and the resulting mixture was refluxed for 1
h. H3PO4 (14 mL, 85%) was added over a period of 10 min. The re-
the synthesis of 1-arylimidazoles and with less than 1% of
sulting mixture was then stirred at reflux for a further 4–8 h. The re-
the desired products being formed (Scheme 1). Following
action was monitored by TLC. After removal of the solvent, the
the method reported by Gridnev,7a we did obtain the de-
dark residue was poured onto ice (300 g) and neutralized with aq
sired 1-aromatic substituted imidazoles, however, the
40% KOH solution until the pH 9. The resulting mixture was ex-
tracted with Et2O (5 × 150 mL). The organic phases were combined
and washed with H2O, brine and dried (Na2SO4). The solvent was
yield was relatively low when sterically hindered 1-aro-
matic substituted imidazoles were the targets (Table 1, en-
tries 1 and 2). Following the procedure modified by removed and the residue was chromatographied on silica gel (petro-
Herrmann,7b similar yield to those that were carried out by
leum ether–EtOAc) to afford the pure products (Table 1). All com-
pounds were characterized by 1H NMR, 13C NMR and GC-MS data.
using Gridnev’s method was obtained. Extension of reac-
tion time as well as elevation of reaction temperature did
1-(2,4,6-Trimethylphenyl)-1H-imidazole7b
Colorless needles; mp 107–108 °C.
IR: (KBr): 3091 (w), 1639 (m), 1602 (m), 1500 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 7.44 (1 H, s), 7.22 (1 H, s), 6.96
(2 H, s), 6.88 (1 H, s), 2.32 (3 H, s, CH3), 1.98 (6 H, s, 2 CH3).
SYNTHESIS 2003, No. 17, pp 2661–2666
Advanced online publication: 21.10.2003
DOI: 10.1055/s-2003-42444; Art ID: P07203SS
© Georg Thieme Verlag Stuttgart · New York
x
x.
x
x
.
2
0
0
3

2662
J. Liu et al.
PAPER
Table 1 Preparation of 1-Arylimidazoles by Modified Procedurea
R1
R1
N
R1
R1
NH2
N
35% Formaldehyde
R1
R1
O
O
MeOH
R.T.
N
O
NH4Cl, 85% H3PO4
+
R
R
R
Entry
1
RNH2
Product
Yield (%)b
43
N
N
NH2
2
45
NH2
N
N
3
4
82
70
O
NH2
O
N
N
NH2
N
N
MeO2C
O
MeO2C
O
5
6
86
71
NH2
NH2
N
N
O
O
O
O
N
N
7
8
30
33
O2N
NH2
O2N
N
N
NH2
N
N
9
24
NH2
N
N
10
11
37
NH2
N
N
9
O
O
N
N
O
Synthesis 2003, No. 17, 2661–2666 © Thieme Stuttgart · New York

PAPER
Synthesis of 1-Arylimidazoles
2663
Table 1 Preparation of 1-Arylimidazoles by Modified Procedurea (continued)
R1
R1
N
R1
R1
NH2
N
35% Formaldehyde
R1
R1
O
O
MeOH
R.T.
N
O
NH4Cl, 85% H3PO4
+
R
R
R
Entry
12
RNH2
Product
Yield (%)b
60
N
N
N
NH2
N
N
N
13
14
15
31
27
16
Ph
Ph
NH2
N
N
Ph
Ph
N
N
NH2
Ph
Ph
NH2
NH2
N
N
Ph
Ph
N
N
Ph
Ph
Ph
O
NH2
O
N
N
Ph
16
28
NH2
N
N
Ph
Ph
17
18
29
33
NH2
N
N
MeOOC
N
MeOOC
N
NH2
N
N
a For reaction conditions see experimental section.
b Isolated yield based on aryl amine.
13C NMR (75 MHz, CDCl3): = 138.95, 137.51, 135.49, 133.43,
129.52, 129.07, 120.15, 21.11, 17.42.
GC-MS: m/z (%) = 187.1 (M+ + 1, 17), 185.8 (M+, 95), 170.0 (9),
159.1 (60), 157.9 (81), 146.0 (25), 143.7 (100), 131.0 (29), 117.0
(17), 114.8 (27).
GC-MS: m/z (%) = 229.2 (M++1, 22), 227.9 (M+, 100), 213.0 (25),
201.1 (38), 185.9 (100), 173.0 (43), 170.0 (35), 158.0 (35), 156.0
(27), 144.0 (37).
HRMS (FAB+): m/z calcd for C15H21N2 [M + H]+: 229.1704; found:
229.1689.
1-(2,6-Diisopropylphenyl)-1H-imidazole
1-(4-Methoxyphenyl)-1H-imidazole7c
Colorless needles; mp 121–122 °C (EtOAc).
Colorless solid; mp 60–61 °C (EtOAc).
IR (KBr): 3095 (m), 1639 (w), 1494 (s), 1472 cm–1 (s).
IR (KBr): 1650 (m), 1614 (w), 1523 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 7.54 (1 H, br s), 7.45 (1 H, dd,
J = 7.6, 7.7 Hz), 7.27 (1 H, br s), 7.25 (2 H, d, J = 7.7 Hz), 6.97 (1
H, br s), 2.38 (2 H, sept, J = 6.8 Hz), 1.14 (12 H, d, J = 6.8 Hz, 4
CH3).
13C NMR (75 MHz, CDCl3): = 146.88, 138.77, 133.12, 130.26,
129.50, 124.16, 122.03, 28.49, 24.82, 24.74.
1H NMR (300 MHz, CDCl3): = 7.77 (1 H, s), 7.30 (2 H, d, J = 8.8
Hz), 7.21 (1 H, s), 7.18 (1 H, s), 6.99 (2 H, d, J = 8.8 Hz ), 3.85 (3
H, s, OCH3).
13C NMR (75 MHz, CDCl3): = 159.26, 136.19, 130.37, 123.54,
119.14, 115.25, 55.96.
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GC-MS: m/z (%) = 175.0 (M+ + 1, 9), 173.9 (M+, 100), 158.7 (19),
146.7 (16), 133.8 (12), 131.6 (65), 119.6 (25), 103.7 (24).
13C NMR (75 MHz, CDCl3): = 139.04, 136.42, 134.78, 134.13,
132.83, 129.28, 122.96, 21.42, 17.78, 13.34, 8.54.
GC-MS: m/z (%) = 215.2 (M+ + 1, 14), 214.1 (M+, 100), 213.0 (20),
199.1 (65), 172.1 (39), 158.0 (73), 145.0 (20), 130.0 (9), 114.9 (18).
HRMS (FAB+): m/z calcd for C14H19N2 [M + H]+: 215.1548; found:
215.1566.
1-(3-Methoxycarbonylphenyl)-1H-imidazole
Colorless solid; mp 40–41 °C (EtOAc).
IR (KBr): 1727 (s), 1611 (w), 1594 (m), 1505 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 8.10 (1 H, br s), 8.06 (1 H, br d,
J = 7.6 Hz), 7.95 (1 H, br s), 7.62 (1H , br s), 7.60 (1 H, dd, J = 7.6,
7.7 Hz), 7.37 (1 H, br s), 7.26 (1 H, br s), 3.99 (3 H, s, OCH3).
1-(2,6-Diisopropylphenyl)-4,5-dimethyl-1H-imidazole
Colorless oil.
13C NMR (75 MHz, CDCl3): = 166.23, 137.85, 135.85, 132.36,
131.16, 130.43, 128.69, 125.79, 122.54, 118.42, 52.89.
GC-MS: m/z (%) = 203.0 (M+ + 1, 25), 201.9 (M+, 100), 172.0 (12),
170.8 (98), 143.9 (22), 142.7 (81), 132.7 (15), 129.9 (22), 116.9
(21), 115.7 (94), 101.7 (7), 88.7 (47).
IR (KBr): 1695 (m), 1589 (m), 1486 (s), 1460 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 7.42 (1 H, t, J = 7.5 Hz), 7.30 (1
H, s), 7.25 (2 H, d, J = 7.5 Hz), 2.37 (2 H, septet, J = 6.8 Hz), 2.26
(3 H, s), 1.86 (3 H, s), 1.14 (6 H, d, J = 6.8 Hz), 1.08 (6 H, d, J = 6.8
Hz).
HRMS (FAB+): m/z calcd for C11H11N2O2 [M + H]+: 203.0820;
found: 203.0860.
13C NMR (75 MHz, CDCl3): = 147.32, 135.95, 133.96, 132.14,
130.07, 124.16, 123.98, 28.33, 25.56, 23.57, 13.38, 8.83.
GC-MS: m/z (%) = 257.4 (M+ + 1, 13), 255.9 (M+, 84), 242.4 (12),
240.9 (78), 226.1 (20), 224.9 (14), 201.3 (17), 199.9 (100), 187.2
(26), 172.0 (29).
HRMS (FAB+): m/z Calcd for C17H25N2 [M + H]+: 257.2017; found:
257.2013.
1-(4-Acetylphenyl)-1H-imidazole9a
Colorless solid; mp 110–111 °C (EtOAc).
IR (KBr): 3107 (w), 1674 (s), 1605 (s), 1519 (m), 1490 cm–1 (m).
1H NMR (300 MHz, CDCl3): = 8.11 (2 H, br d, J = 6.8 Hz), 8.00
(1 H, s), 7.54 (2 H, br d, J = 6.8 Hz), 7.40 (1 H, s), 7.26 (1 H, s), 2.66
(3 H, s, CH3).
4,5-Diethyl-1-(2,4,6-trimethylphenyl)-1H-imidazole
Brown oil.
13C NMR (75 MHz, CDCl3): = 196.90, 141.00, 136.01, 135.69,
131.41, 130.65, 120.95, 118.04, 26.96.
IR (KBr): 1685 (w), 1611 (w), 1577 (w), 1491 (s), 1460 cm–1 (m).
GC-MS: m/z (%) = 185.9 (M+, 96), 170.9 (90), 142.8 (100), 115.8
(87), 101.8 (8), 88.8 (52).
1H NMR (300 MHz, CDCl3): = 7.21 (1 H, s), 6.96 (2 H, s), 2.60
(2 H, q, J = 7.5 Hz), 2.33 (3 H, s, CH3), 2.28 (2 H, q, J = 7.5 Hz ),
1.95 (6 H, s, 2 CH3), 1.28 (3 H, t, J = 7.5 Hz), 0.90 (3 H, t, J = 7.5
Hz).
1-(4-Methoxycarbonylphenyl)-1H-imidazole9b
Colorless solid; mp 128–129 °C (EtOAc).
IR (KBr): 1714 (s), 1610 (s), 1527 cm–1 (s).
13C NMR (75 MHz, CDCl3): = 139.75, 138.99, 136.37, 135.06,
132.78, 129.33, 128.23, 21.38, 21.03, 17.79, 16.71, 15.05, 14.64.
1H NMR (300 MHz, CDCl3): = 8.14 (2 H, dd, J = 0.8, 8.7 Hz),
7.93 (1 H, s), 7.45 (2 H, dd, J = 0.8, 8.7 Hz), 7.33 (1 H, d, J = 0.8
Hz), 7.22 (1 H, s), 3.93 (3 H, s, OCH3).
GC-MS: m/z (%) = 243.6 (M+ + 1, 6), 242.5 (M+, 43), 228.5 (14),
227.5 (100), 213.5 (40), 197.4 (7), 184.7 (6), 170.4 (6), 158.4 (10),
145.4 (9), 130.3 (8), 119.3 (10), 115.4 (11).
13C NMR (75 MHz, CDCl3): = 166.36, 141.09, 135.77, 131.92,
131.49, 129.37, 120.97, 118.12, 52.76.
HRMS (FAB+): m/z calcd for C16H23N2 [M + H]+: 243.1861; found:
243.1830.
GC-MS: m/z (%) = 203.0 (M+ + 1, 18), 201.9 (M+, 100), 172.0 (15),
170.9 (96), 144.0 (17), 142.8 (91), 129.9 (11), 115.8 (74), 88.8 (42).
HRMS (FAB+): m/z calcd for C11H11N2O2 [M + H]+: 203.0820;
found: 203.0802.
1-(3,4,5-Trimethoxyphenyl)-1H-imidazole
Colorless oil.
IR (KBr): 3118 (w), 1600 (s), 1510 (s), 1465 (s), 1425 cm–1 (m).
1H NMR (300 MHz, CDCl3): = 7.76 (1 H, br s), 7.20 (1 H, t,
J = 1.2 Hz), 7.15 (1 H, br s), 6.55 (2 H, s), 3.87 (6 H, s, 2 OCH3),
3.84 (3 H, s, OCH3).
1-(4-Nitrophenyl)-1H-imidazole9c
Colorless solid; mp 177–178 °C (acetone).
IR (KBr): 3131 (m), 1679 (m), 1613 (s), 1599 (s), 1529 (s), 1511
cm–1 (s).
13C NMR (75 MHz, CDCl3): = 154.36, 137.86, 136.26, 133.76,
130.53, 119.15, 100.17, 61.37, 56.72.
1H NMR (300 MHz, CDCl3): = 8.33 (2 H, d, J = 9.0 Hz), 7.97 (1
H, br s), 7.56 (2 H, d, J = 9.0 Hz), 7.37 (1 H, br s), 7.24 (1 H, br s).
13C NMR (75 MHz, CDCl3): = 146.61, 142.37, 135.80, 132.08,
126.14, 121.42, 118.04.
GC-MS: m/z (%) = 235.1 (M+ + 1, 12), 234.0 (M+, 100), 220.1 (10),
219.0 (90), 203.9 (3), 190.9 (25), 175.9 (27), 160.8 (18), 148.9 (12),
131.9 (13).
HRMS (FAB+): m/z calcd for C12H15N2O3 [M + H]+: 235.1082;
found: 235.1066.
GC-MS: m/z (%) = 190.0 (M+ + 1, 9), 188.9 (M+, 100), 161.9 (4),
141.9 (7), 131.8 (17), 115.8 (57).
2-Imidazol-1-yl-4,6-dimethylpyrimidine
Colorless solid; mp 77–78 °C (acetone).
IR (KBr): 3161 (m), 1599 (s), 1547 (m), 1477 cm–1 (s).
4,5-Dimethyl-1-(2,4,6-trimethylphenyl)-1H-imidazole
Colorless solid; mp 138–139 °C (acetone).
IR (KBr): 3103 (w), 1702 (s), 1592 (m), 1492 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 8.59 (1 H, s), 7.87 (1 H, t, J = 1.1
Hz), 7.11 (1 H, t, J = 1.1 Hz), 6.87 (1 H, s), 2.47 (6 H, s, 2 CH3).
13C NMR (75 MHz, CDCl3): = 183.62, 169.25, 136.60, 130.62,
118.14, 116.96, 24.24.
1H NMR (300 MHz, CDCl3): = 7.23 (1 H, s), 6.95 (2 H, s), 2.32
(3 H, s, CH3), 2.23 (3 H, s, CH3), 1.91 (6 H, s, 2 CH3), 1.83 (3 H, s,
CH3).
Synthesis 2003, No. 17, 2661–2666 © Thieme Stuttgart · New York

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Synthesis of 1-Arylimidazoles
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GC-MS: m/z (%) = 175.5 (M+ + 1, 21), 173.9 (M+, 53), 149.5 (6),
147.8 (100), 133.4 (2), 132.1 (6), 123.3 (4), 119.2 (7), 108.5 (6),
107.2 (27).
HRMS (FAB+): m/z calcd for C9H11N4 [M + H]+: 175.0983; found:
175.1002.
1-(3-Methoxycarbonylphenyl)-4,5-dimethyl-1H-imidazole
Colorless oil.
IR (KBr): 1721 (s), 1645 (s), 1499 (m), 1453 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 8.09 (1 H, d, J = 7.7 Hz), 7.95 (1
H, t, J = 1.8 Hz), 7.58 (1 H, t, J = 7.7 Hz), 7.52 (1 H, s), 7.47 (1 H,
dd, J = 1.8, 7.7 Hz), 3.95 (3 H, s, OCH3), 2.24 (3 H, s, CH3), 2.12 (3
H, s, CH3).
13C NMR (75 MHz, CDCl3): = 166.30, 137.59, 135.39, 135.27,
132.10, 130.06, 130.02, 129.42, 126.82, 123.14, 52.85, 13.16, 9.50.
GC-MS: m/z (%) = 231.1 (M+ + 1, 11), 230.0 (M+, 100), 229.0 (78),
215.0 (22), 198.9 (10), 187.9 (7), 171.0 (11), 161.9 (10), 143.9 (20),
129.9 (17).
(1R,2R)-1,2-Diimidazol-1-yl-1,2-diphenylethane
Colorless solid; mp 265–266 °C (MeOH–CHCl3).
IR (KBr): 3101 (w), 1495 (s), 1456 (m), 1425 cm–1 (w).
1H NMR (300 MHz, CDCl3): = 7.32–7.19 (12 H, m), 6.99 (2 H, t,
J = 0.97 Hz), 6.77 (2 H, t, J = 1.3 Hz), 5.88 (2 H, s).
13C NMR (75 MHz, CDCl3): = 136.68, 135.95, 130.58, 129.59,
129.43, 128.36, 117.70, 65.08.
HRMS (FAB+): m/z calcd for C13H15N2O2 [M + H]+: 231.1133;
found: 231.1158.
GC-MS: m/z (%) = 315.0 (M+ + 1, 2), 313.9 (M+, 13), 280.8 (1),
244.8 (1), 177.7 (12), 156.8 (100), 129.8 (45), 114.8 (4), 102.7 (28).
8-Imidazol-1-yl-quinoline
Brown solid; mp 111–112 °C (acetone).
HRMS (FAB+): m/z calcd for C20H19N4 [M + H]+: 315.1609; found:
315.1637.
IR (KBr): 3127 (w), 1668 (m), 1617 (m), 1599 (s), 1574 (m), 1508
(s), 1397 cm–1 (s).
(1S,2S)-1,2-Diimidazol-1-yl-1,2-diphenylethane
Colorless solid; mp 265–266 °C (MeOH–CHCl3).
IR (KBr): 3101 (w), 1495 (s), 1456 cm–1 (m).
1H NMR (300 MHz, CDCl3): = 7.32-7.19 (12 H, m), 6.98 (2 H, br
s), 6.76 (2H, br s), 5.87 (2 H, s).
13C NMR (75 MHz, CDCl3): = 136.66, 135.92, 130.53, 129.59,
129.44, 128.35, 117.69, 65.10.
GC-MS: m/z (%) = 315.0 (M++1, 3), 313.9 (M+, 15), 244.9 (1),
177.8 (11), 156.9 (100), 129.9 (46), 114.8 (4), 102.9 (24).
HRMS (FAB+): m/z calcd for C20H19N4 [M + H]+: 315.1609; found:
315.1628.
1H NMR (300 MHz, MeOD): = 7.28 (1 H, br s), 6.78 (1 H, d,
J = 8.2 Hz), 6.61 (1 H, s), 6.36 (1 H, d, J = 8.2 Hz), 6.19 (1 H, d,
J = 7.4 Hz), 6.06 (1 H, t, J = 8.2 Hz), 5.99 (1 H, s), 5.96 (1 H, t,
J = 7.4 Hz), 5.59 (1 H, s).
13C NMR (75 MHz, CDCl3): = 151.09, 141.81, 138.91, 136.75,
134.27, 129.68, 128.41, 127.62, 126.40, 124.89, 122.32, 121.67.
GC-MS: m/z (%) = 196.5 (M+ + 1, 15), 195.0 (M+, 73), 170.5 (12),
168.7 (100), 155.3 (38), 140.3 (21), 129.4 (20), 128.1 (27), 114.4
(16), 101.3 (29).
HRMS (FAB+): m/z calcd for C12H10N3 [M + H]+: 196.0874; found:
196.0862.
1-(2,6-Diphenyl-4-methoxyphenyl)-1H-imidazole
Colorless solid; mp 220–222 °C (acetone).
IR (KBr): 3087 (w), 1596 (m), 1574 (m), 1501 (m), 1465 cm–1 (m).
Acknowledgment
This work was partially supported by a Grant (2002GH04) from the
International Cooperation Division of Yunnan provincial Science &
Technology Department.
1H NMR (300 MHz, CDCl3): = 7.28–7.22 (6 H, m), 7.15–7.04 (5
H, m), 7.00 (2 H, s), 6.79 (1 H, s), 6.53 (1 H, s), 3.88 (3 H, s, OCH3).
13C NMR (75 MHz, CDCl3): = 159.24, 141.13, 138.73, 138.25,
128.71, 128.45, 128.07, 127.77, 125.98, 121.83, 115.40, 55.76.
GC-MS: m/z (%) = 327.3 (M+ + 1, 19), 325.4 (M+ – 1, 100), 299.3
(9), 297.9 (44), 286.0 (52), 281.8 (30), 253.8 (28), 243.0 (11),
225.8(12), 214.5 (11).
References
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HRMS (FAB+): m/z calcd for C22H19N2O [M + H]+: 327.1497;
found: 327.1523.
4,5-Diphenyl-1-(2,4,6-trimethylphenyl)-1H-imidazole
Yellow solid; mp 146–148 °C (acetone).
IR (KBr): 3139 (m), 1601 (s), 1498 (s), 1448 (s), 1401 cm–1 (s).
1H NMR (300 MHz, CDCl3): = 7.60 (2 H, d, J = 7.3 Hz), 7.51 (1
H, s), 7.22 (2 H, t, J = 7.3 Hz), 7.19–7.05 (6 H, m), 6.85 (2 H, s),
2.25 (3 H, s, CH3), 1.98 (6 H, s, 2 CH3).
13C NMR (75 MHz, CDCl3): = 139.21, 138.89, 137.71, 136.19,
135.09, 132.49, 130.76, 130.16, 129.39, 129.34, 128.81, 128.58,
128.35, 127.61, 126.97, 21.44, 18.27.
GC-MS: m/z (%) = 339.5 (M+ + 1, 25), 338.4 (M+, 100), 337.4 (21),
321.4 (3), 308.4 (1), 294.4 (3), 281.4 (4), 261.3 (3), 253.3 (2), 234.4
(75), 220.4 (20), 207.2 (17), 190.3 (8), 178.3 (12), 165.2 (43), 158.3
(27), 144.3 (16).
HRMS (FAB+): m/z calcd for C24H23N2 [M + H]+: 339.1861; found:
339.1879.
Synthesis 2003, No. 17, 2661–2666 © Thieme Stuttgart · New York

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