One-pot synthesis of polysubstituted imidazoles from arylaldehydes in water catalyzed by nhc using microwave irradiation

Article abstract of DOI:10.4067/S0717-97072012000300002

A simple, high yielding synthesis of tri (3a-i) and tetrasubstituted (4a-g) imidazols from aldehydes is described. The cornerstone of this methodology involves the condensation of NH4OAc, substituted aldehydes, and benzoin, which is synthesized in situ from aldehydes catalyzed by N-heterocyclic carbine (NHC), under microwave irradiation in water to afford trisubstituted imidazoles (3a-i). If arylamine is added in the solution, tetrasubstituted imidazoles (4a-g) can be obtained. Lepidilines B and trifenagrel are also synthesized in high yield using this procedure. All the experiment deta are in agreement with the literature.

Full text of DOI:10.4067/S0717-97072012000300002

J. Chil. Chem. Soc., 57, Nº 3 (2012)
ONE-POT SYNTHESIS OF POLYSUBSTITUTED IMIDAZOLES FROM ARYLALDEHYDES IN WATER
CATALYZED BY NHC USING MICROWAVE IRRADIATION
LEI WU1, XIAOBI JING11*, HONGXIANG ZHU2, YINLIN LIU1, CHAOGUO YAN1
1College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, P. R. China
2 School of Light Industrial and Food Engineering, Guangxi University, Nanning, P. R. China
(Received: January , 2011 - Accepted: January 26, 2012)
ABSTRACT
A simple, high yielding synthesis of tri (3a-i) and tetrasubstituted (4a-g) imidazols from aldehydes is described. The cornerstone of this methodology involves
the condensation of NH4OAc, substituted aldehydes, and benzoin, which is synthesized in situ from aldehydes catalyzed by N-heterocyclic carbine (NHC), under
microwave irradiation in water to afford trisubstituted imidazoles (3a-i). If arylamine is added in the solution, tetrasubstituted imidazoles (4a-g) can be obtained.
Lepidilines B and trifenagrel are also synthesized in high yield using this procedure. All the experiment deta are in agreement with the literature.
Keywords: Trisubstituted imidazoles, tetrasubstituted imidazoles, microwave irradiation, Lepidilines B, Trifenagrel, N-heterocyclic carbine (NHC)
INTRODUCTION
Imidazole ring system is one of the most important substructures found in
a large number of natural products and pharmacologically active compounds
such as antiulcerative agent cimetidine 1, the proton pump inhibitor omeprazole
2 and the benzodiazepine antagonist flumazenil 3 are imidazole derivatives. In
addition, the substituted imidazole ring system is substantially used in ionic
liquids4 that have been given a new approach to “green chemistry”.
Triarylimidazole or tetraarylimidazole compounds have gained remarkable
importance due to their widespread biological activities and their use in
synthetic chemistry. 5
In the literature, there are several methods reported for the synthesis of
8
2,4,5-triarylimidazoles using zeolite HY/silica gel 6, ZrCl4 7, NiCl2·6H2O
,
ionic liquid 9, iodine 10, Sodium bisulfite 11 from the starting material of benzil.
However, these methods require prolonged reaction time, exotic reaction
condition and most importantly require expensive and hazardous acid or metal
catalysts.
General methods relay on the synthesis of trisubstituted imidazoles
followed by installation of the fourth substituent via N-alkylation [11], metal
activated coupling12, or imidazole-N-oxides13 to generate tetrasubstituted
imidazoles.
Scheme 1 synthesis of triphenyl imidazole
We have reported [16] that if FeCl was not used after the condensation of
aldehyde the mixture of benzil and be3nzoin can be obtained because of the air
oxidation. Base on this discovery, we tried to obtain triphenyl imidazole in one-
pot without any oxydation of metal ion which is unfriendly to environment.
Initial result shown that when aldehyde and NH4OAc were added directly into
the benzil and benzoin mixture solution, which was obtained from aldehyde
in situ catylized by N-heterocyclic carbene, after reflux for 12 h under air
condition without any FeCl3 , the yield of triphenyl imidazole was also very
good, as shown in Scheme 2.
Tetrasubstituted imidazoles can be directly prepared from benzil or
benzoin condensation with aldehydes, amines and ammonium acetate but in
14
this procedure the hazardous catalyst of K5CoW12O40·3H2O or molecular
iodine 15 is needed.
Wolkenberg 15b reported in 2004 that 1,2-diketones and aldehydes can be
condensed to form trisubstituted imidazoles in the presence of NH OAc without
any catalyst, but this method can only be used to synthesize 4trisubstituted
imidazoles. Moreover, the synthesis of trisubstituted imidazoles was carried
out in acetic acid leading to complex isolation and recovery procedures.
Therefore, the development of simple, efficient, inexpensive providing
convenient procedure with improved yield for the synthesis of polysubstituted
imidazoles is necessary.
To the best of our knowledge, one-pot synthesis of polysubstituted
imidazoles directly from arylaldehyde in stead of benzil or benzoin has not
been reported in the literature. Very recently, we reported 16 our work on the
synthesis of 1,2-diketones from arylaldehyde via organocatalysis. Based on this
work, we developed a new method to synthesize polysubstituted imidazoles in
one-pot from the starting material of arylaldehyde. Herein, we disclose our
experimental result.
Scheme 2 synthesis of triphenyl imidazole without any metal oxidant
RESULTS AND DISCUSSION
In order to deduce the reaction time, improved method, such as MAOS,
was tested to be used in this reaction. It is well known that microwave-assisted
organic synthesis (MAOS) has had a significant impact on synthetic chemistry.
Reductions in reaction time, increase in yield and suppression of side product
formation have all been described for microwave conditions relative to
conventional thermal heating 17,5b. Based on this knowledge, microwave
irradiation was used instead of refluxing in the one-pot sequence under air
atmosphere. Impressively, the yield of triphenyl imidazole can be improved to
95% while the reaction time was deduced to only 10 min. (Scheme 3)
Initially, we supposed triphenyl imidazole can be synthesized in one-
pot from the condensation of phenylaldehyde, NH4OAc and benzil, which
was synthesized in situ according our previous method 16. Experimental test
resulted in very good yield, as shown in Scheme 1.
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J. Chil. Chem. Soc., 57, Nº 3 (2012)
the benzil and benzoin mixture solution, under the same condition discribed
above, tetrasubstituted imidazoles could also be synthesized. All the results are
list in scheme 5 and table 3.
Scheme 3 synthesis of triphenyl imidazole using microwave irradiation
Different solvents were also screened in this reaction, resulting that water
is the best solvent. All the results are summarized in Table 1.
Scheme 5 synthesis of terisubsituted imidazoles
Table 1. Synthesis of triphenyl imidazole in different solvents
Table 3. One-pot synthesis of tetrasubstituted imidazoles from different
arylamines
Entry
Solvent
Time(min)
Yield(%)a
Entry
R2
R3
Product Yield(%)a
Mp(ºC)
1
2
3
4
CH3CH2OH
THF
5+5
5+5
5+5
5+5
87
66
95
65
1
2
3
4
5
6
7
Ph
Ph
Ph
4a
4b
4c
4d
4e
4f
91
87
89
88
88
86
84
163-165
192-194
180-182
155-157
172-174
167-169
144-146
4-Cl-ph
4-CH3-ph
Ph
4-CH3-ph
4-Cl-ph
3-Cl-ph
H O
CH23CN
4-CH3O-ph
4-CH3-ph
Ph
4-CH3-ph
Ph
a: isolated yields
4g
Encouraged by the aforementioned results and with the suitable reaction
conditions in hand, we tested the feasibility of the protocol using various
arylaldehydes. Fortunately, this procedure provided a straight forward synthetic
route to the trisubstituted imidazoles. All the results are list in Scheme 4 and
Table 2.
a: isolated yields
Lepidiline B18, which exhibit micromolar cytotoxicity against several
human cancer cell lines, were isolated from the root extract of lepidium meyenii
collected from the Andes Mountains of Peru during a search for bioactive
natural products. We synthesized Lepidiline B using our method described
above. (Scheme 6) Lepidiline B was first synthesized in a two-step procedure
from 2, 3-butanedione and acetaldehyde in 43% overall yield. While using our
one-pot procedure directly from acetaldehyde, the yield is about 67%.
Scheme 4 synthesis of trisubsituted imidazoles.
Table 2. one-pot synthesis of trisubstituted imidazoles from different
arylaldehydes.
Yield(%)
Entry
R1
R2
Product
Mp(ºC)
a
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Ph
Ph
Ph
4-CH3-ph
4-CH3O-ph
Ph
4-CH3O-ph
Ph
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
95
94
82
96
94
96
98
92
85
trace
trace
none
none
none
276-278
231-232
256-257
282-284
238-240
272-274
296-298
236-238
240-242
---
Scheme 6 synthesis of Lepidiline B
4-CH O-ph
3-C3l-ph
3-Cl-ph
3-Br-ph
4-Cl-ph
4-Cl-ph
4-CH3-ph
2-Furanyl
2-Pyridinyl
3-NO -ph
4-NO22-ph
4-OH-ph
19
Trifenagrel
is a potent arachidonate cyclo-oxygenase inhibitor that
reduces platelet aggregation in several animal species and humans. Preparation
of the drug using our one-pot condensation reaction proceeded smoothly and
in high yield. This example highlights the speed of the method: whereas the
existing optimized procedure for its preparation furnishes product after 2 h at
reflux from dione, the one-pot protocol delivers trifenagrel in 95% yield after
10 min directly from aldehyde. (Scheme 7)
Ph
2-OH-ph
4-CH3-ph
Ph
3-NO2-ph
Ph
---
---
---
---
4-CH3
4-Cl-ph
a: isolated yields
From table 2, it shows that the yields of trisubstituted imidazoles from the
starting material of phenyl aldehyde bearing chloro, bromo or methyl substitute
were very good, while using furanyl, pyridinyl, nitro and hydroxyl phenyl
aldehyde, trisubstituted imidazoles can not be obtained, because these kinds of
benzoins can not be synthesized in situ.
When arylamine along with NH4OAc and arylaldehyde were added into
Scheme 7 synthesis of trifenagrel
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J. Chil. Chem. Soc., 57, Nº 3 (2012)
In conclusion, we have reported here in several noteworthy features of a
new method for the synthesis of polysubstituted imidazoles from aldehydes
in one-pot using microwave irradiation. This protocol offers many attractive
features such as reduced reaction times, higher yields and economic viability
of the one-pot sequence.
= 7.3 Hz, 2H, Ar-H), 7.62 (d, J = 7.8 Hz, 2H, Ar-H), 7.51-7.43 (m, 6H, Ar-H),
7.41 (t, J = 7.4 Hz, 1H, Ar-H), 7.35 (t, J = 7.8 Hz, 1H, Ar-H), 7.31 (d, J = 8.2
Hz, 1H, Ar-H); 13C NMR (150 MHz, DMSO-d6) δ: 146.2 (C=N), 133.4, 133.0,
132.6, 130.6, 130.2, 129.9, 128.7, 128.6, 127.9, 127.8, 127.4, 127.0, 126.6,
126.5, 125.4, 125.3; IR (KBr): 3450(NH), 1600(C=C), 1585(Ph), 889(Ar-H),
788(Ar-H), 751(Ar-H), 690(Ar-H) cm-1.
EXPERIMENTAL
4,5-bis(3-chlorophenyl)-2-(4-methoxyphenyl)-1H-imidazole (3e): white
solid, mp: 238-240 ºC; 1H NMR (600 MHz, DMSO-d6) δ: 12.68 (s, 1H,
N-H), 8.02 (d, J = 8.7 Hz, 2H, Ar-H), 7.61 (s, 2H, Ar-H), 7.44-7.31 (m, 6H,
Ar-H), 7.06 (d, J = 8.8 Hz, 2H, Ar-H), 3.82 (s, 3H, OCH3); 13C NMR (150
MHz, DMSO-d6) δ: 159.7 (Ar-O), 146.3 (C=N), 133.4, 130.5, 130.1, 127.8,
126.9, 125.5, 122.6, 114.1, 55.20 (OCH3); IR (KBr): 3452(NH), 3027(Ar-H),
1598(C=C), 1564(Ph), 1249(Ar-H), 788(Ar-H) cm-1
4,5-bis(3-bromophenyl)-2-phenyl-1H-imidazole (3f): white solid, mp:
272-274 ºC; 1H NMR (600 MHz, DMSO-d6) δ: 12.87 (s, 1H, N-H), 8.08 (d, J
= 7.8 Hz, 2H, Ar-H), 7.77(s, 2H, Ar-H), 7.61 (d, J = 6.9 Hz, 1H, Ar-H), 7.51-
7.45 (m, 5H, Ar-H), 7.41 (t, J = 7.3 Hz, 2H, Ar-H), 7.29 (t, J = 7.5 Hz, 1H,
Ar-H); 13C NMR (150 MHz, DMSO-d6) δ: 146.2 (C=N), 135.3, 133.1, 131.7,
131.5, 131.1, 130.7, 130.5, 129.8, 128.7, 128.6, 127.5, 125.3, 123.6; IR (KBr):
3417(NH), 3060(Ar-H), 1588(C=C), 1466(Ph), 1407(Ph), 888(Ar-H), 784(Ar-
H), 691(Ar-H) cm-1.
4,5-bis(4-chlorophenyl)-2-phenyl-1H-imidazole (3g): white solid, mp:
296-298 ºC; 1H NMR (600 MHz, DMSO-d6) δ: 12.76 (s, 1H, N-H), 8.07 (d, J
= 7.8 Hz, 2H,Ar-H), 7.55-7.47 (m, 8H, Ar-H), 7.39 (t, J = 7.4 Hz, 3H, Ar-H);
13C NMR (150 MHz, DMSO-d6) δ: 145.9 (C=N), 133.7, 132.4, 131.1, 130.1,
130.0, 129.5, 128.8, 128.7, 128.4, 128.3, 127.3, 125.2; IR (KBr): 3446(NH),
1636(C=C), 1491(Ph), 1093(Ar-H), 833(Ar-H) cm-1.
2-(4,5-bis(4-chlorophenyl)-1H-imidazole-2-yl)phenol (3h): white solid,
mp: 236-238 ºC; 1H NMR (600 MHz, DMSO-d ) δ: 13.07 (s, 1H, N-H), 12.67
(s, 1H), 8.02 (d, J = 7.8 Hz, 1H, Ar-H), 7.54-7.644 (m, 8H, Ar-H), 7.29 (t, J =
7.7 Hz, 1H, Ar-H), 6.99-6.95 (m, 2H, Ar-H); 13C NMR (150 MHz, DMSO-d6)
δ: 156.5 (Ar-O), 146.2 (C=N), 130.4, 130.3, 128.9, 128.7, 128.5, 125.0,
118.9, 116.8, 112.6; IR (KBr): 3445(NH), 3235(C-H), 1590(C=C), 1495(Ph),
1430(Ph), 1254(Ar-H), 1093(Ar-H), 830(Ar-H) cm-1. Compound 3h were also
confirmed by X-ray single crystal analysis as shown in Figure 1.
General
Melting points were obtained on a hot-plate microscope apparatus and
were uncorrected. 1H and 13C NMR spectra were recorded with a Bruker AV-
600 spectrophotometer. IR spectra were obtained on a Nicolet FT-IR 740
spectrometer (KBr disc). X-ray data were collected on a Bruker Smart APEX-2
diffractometer.
General procedure for the synthesis of triarylimidazole (3a-i)
A mixture of benzimidazolium salt (0.25 mmol, 0.11 g), arylaldehyde
(5 mmol), 2 mL 10% aqua NaOH and 10 mL water was irradiated at 350w
for 5 min in a microwave synthesizer. After adding HOAc to pH=6-7, then
NH4OAc (10 mmol, 0.77 g) and aldehyde (5 mmol) were added. The mixture
was irradiated for 5 min again. The reaction mixture was allowed to cool to 0
ºC. The precipitated solid was filtered. The crude product on recrystallization
from EtOH yielded the requisite trisubstituted imidazoles.
General procedure for the synthesis of tetraarylimidazole (4a-g)
A mixture of benzimidazolium salt (0.25 mmol, 0.11 g), arylaldehyde (5
mmol), 2 mL 10% aqua NaOH and 10 mL water was irradiated at 350w for 5
min in a microwave synthesizer. After adding HOAc to pH=6-7, then NH4OAc
(5 mmol, 0.39 g), aldehyde (5 mmol) and arylamine (5 mmol) were added.
The mixture was irradiated for 5 min again. The reaction mixture was allowed
to cool to 0 ºC. The precipitated solid was filtered. The crude product on
recrystallization from EtOH yielded the requisite tetrasubstituted imidazoles.
The synthesis of Lepidiline B
A mixture of benzimidazolium salt (0.25 mmol, 0.11 g), Acetaldehyde (5
mmol, 0.22 g), 2 mL 10% aqua NaOH and 10 mL water was irradiated at 350w
for 5 min in a microwave synthesizer. After adding HOAc to pH=6-7, NH4OAc
(10 mmol, 0.77 g) and Acetaldehyde (5 mmol, 0.22 g) were added. The mixture
was irradiated for 5 min again. The reaction mixture was allowed to cool to
room temperature. Then Benzyl chloride (1.27 g, 10 mmol) and 1.5 mL Et N
were added. The mixture was continually irradiated for 5 min. The reacti3on
mixture was allowed to cool to 0 ºC. The precipitated solid was filtered. The
crude product on recrystallization from EtOH yielded the requisite natural
product Lepidiline B (1.089 g, 67%) as a solid, mp: 220-222 ºC; 1H NMR (600
MHz, DMSO-d6) δ: 7.45-7.36 (m, 6H, Ar-H), 7.15 (d, J = 7.2 Hz, 4H, Ar-H),
5.45 (s, 4H, CH ), 2.63 (s, 3H, CH3), 2.13 (s, 6H, CH ); 13CNMR (150 MHz,
DMSO-d6) δ: 1423.6 (C=N), 134.5, 129.0, 128.3, 126.5,3125.8, 47.7 (CH2), 10.3
(CH3), 8.2 (CH3); IR (KBr): 3400(H2O), 2360(N+=C), 1648(C=C), 1525(Ph),
1454(Ph), 742(Ph), 712(Ph) cm-1.
Figure 1. X-ray structure of compound 3h.
2,4,5-tri-p-tolyl-1H-imidazole (3i): white solid, mp: 240-242 ºC; 1H NMR
(600 MHz, CDCl3) δ: 9.60 (s, 1H, N-H), 7.74 (d, J = 7.6 Hz, 2H, Ar-H), 7.40
(m, 4H, Ar-H), 7.19 (d, J = 7.6 Hz, 2H, Ar-H), 7.11 (d, J = 6.9 Hz, 4H, Ar-H),
2.36 (s, 3H, CH3), 2.34 (s, 6H, CH ); 13C NMR (150 MHz, CDCl3) δ: 147.7,
145.8 (C=N), 138.6, 138.3, 135.8, 3129.6, 129.5, 129.2, 128.9, 127.6, 127.2,
125.1, 21.3 (CH3), 21.2 (CH3); IR (KBr): 3450(NH), 3030(Ar-H), 1620(C=C),
1499(Ph), 819(Ph-H), 727(Ph-H) cm-1.
2,4,5-triphenyl-1-(4-chlorophenyl)-imidazole (4b): white solid, mp: 192-
1
The synthesis of Trifenagrel
194 ºC; H NMR (600 MHz, DMSO-d6) δ: 7.45-7.57 (m, 12H, Ar-H), 7.30(d
A mixture of benzimidazolium salt (0.25 mmol, 0.11 g), benzaldehyde (5
mmol, 0.53 g), 2 mL 10% aqua NaOH and 10 mL water was irradiated at 350w
for 5 min in a microwave synthesizer. After adding HOAc to pH=6-7, then
NH4OAc (10 mmol, 0.77 g) and 2-[2-(dimethylamino)ethoxy]benzaldehyde
(5 mmol, 0.98 g) were added. The mixture was irradiated for 5 min again.
The reaction mixture was allowed to cool to 0 ºC. The precipitated solid was
filtered. The crude product on recrystallization from EtOH yielded the requisite
natural product Trifenagrel (1.819, 95%) as a solid, mp: 147-148 ºC; 1H NMR
(600 MHz, CDCl3) δ: 12.20 (s, 1H, N-H), 8.48 (d, J = 7.8 Hz, 1H, Ar-H), 7.64
(d, J = 7.2 Hz, 2H, Ar-H), 7.48 (d, J = 6.3 Hz, 2H, Ar-H), 7.40-7.27 (m, 8H,
Ar-H), 7.11 (t, J = 7.5 Hz, 1H, Ar-H), 7.01 (d, J = 8.4 Hz, 1H, Ar-H), 4.24 (dd,
J = 5.1, 6.0 Hz, 2H, CH2-O), 2.67 (dd, J = 5.1, 5.4 Hz, 2H, CH2-N), 1.98 (s, 6H,
CH3); 13CNMR (150 MHz, CDCl3) δ: 154.5 (Ar-O), 146.9 (C=N), 133.2, 129.5,
129.3, 128.6, 128.1, 127.1, 121.0, 117.2, 114.6, 66.8 (CH2-O), 58.9 (CH2-N),
45.5 (CH3); IR (KBr): 3454(NH), 3032(Ar-H), 1598(C=N), 1500(Ph), 1254(C-
O), 1092(C-O-C), 830(Ph) cm-1.
J = 7.8 Hz, 2H,Ar-H), 7.22(d J = 7.8 Hz, 2H,Ar-H), 7.40 (m, 3H, Ar-H); IR
(KBr): 3010(Ar-H), 1650(C=C), 1480(Ph), 800(Ph-H), cm-1.
1-p-tolyl-2-(4-methoxylphenyl)-4,5-diphenylimidazole(4c): white solid,
mp: 180-182 ºC. 1H NMR (600 MHz, DMSO-d6) δ: 7.74 (d, J = 7.6 Hz, 2H, Ar-
H), 7.42-7.50(m, 12h, Ar-H), 7.19 (d, J = 7.6 Hz, 2H, Ar-H), 7.05(m, 2h, Ar-
H), 3.80 (s, 3H, OCH3), 2.40 (s, 3H, CH3), IR (KBr): 3003(C-H), 1600(C=C),
1477(Ph), 1428(Ph), 1254(Ar-H), 1093(Ar-O), 830(Ar-H) cm-1.
1
1,4,5-triphenyl-2-p-tolylimidazole(4d): white solid, mp: 155-157 ºC. H
NMR (600 MHz, DMSO-d6) δ: 7.80 (d, J = 7.4 Hz, 2H, Ar-H), 7.53 (d, J = 7.4
Hz, 2H, Ar-H), 7.38-7.40(m, 12h, Ar-H), 7.13(m, 3h, Ar-H), 2.35 (s, 3H, CH3),
IR (KBr): 2999(C-H), 1593(C=C), 1460(Ph), 1255(Ar-H), 833(Ar-H) cm-1.
2,4,5-triphenyl-1-p-tolylimidazole(4e) white solid, mp: 172-174 ºC. 1H
NMR (600 MHz, DMSO-d6) δ: 7.43-7-55 (m,12H, Ar-H), 7.30-7.39(2m, 12h,
Ar-H), 7.26 (d, J = 7.4 Hz, 2H, Ar-H), 7.13(m, 3h, Ar-H), 2.35 (s, 3H, CH3), IR
(KBr): 3090(C-H), 1515(C=C), 1500(Ph), 1234(Ar-H), 775(Ar-H) cm-1.
1-p-chlorophenyl-2-p-tolyl-4,5-diphenylimdazole(4f) white solid, mp:
167-169 ºC. 1H NMR (600 MHz, DMSO-d6) δ: 8.02 (d, J = 7.8 Hz, 2H,Ar-H),
7.50-7.45 (m, 12H, Ar-H), 7.39 (d, J = 7.8 Hz, 2H,Ar-H); 7.23(m, 2H, Ar-
H),2.35 (s, 3H, CH3), IR (KBr): 3028(C-H), 1644(C=C), 1531(Ph), 1212(Ar-
H), 890(Ar-H) cm-1.
Spectral data for novel compounds:
2,4,5-tris(4-methoxyphenyl)-1H-imidazole (3c): white solid; mp: 256-257
ºC; 1H NMR (600 MHz, CDCl ) δ: 7.91 (d, J = 8.3 Hz, 2H, Ar-H), 7.38 (d, J
= 8.4 Hz, 2H, Ar-H), 6.83 (d, J3= 8.5 Hz, 6H, Ar-H), 3.82 (s, 3H, OCH3), 3.81
(s, 6H, OCH3); 13C NMR (150 MHz, CDCl3) δ: 160.4 (Ar-O), 159.2 (Ar-O),
144.9 (C=N), 129.3, 127.5, 123.4, 114.2, 113.9, 55.3 (OCH3), 55.2 (OCH3); IR
(KBr): 3450(NH), 1611(C=C), 1501(Ph), 1253(Ar-H), 1185(Ar-H), 1030(Ar-
H), 840(Ar-H) cm-1.
1,4,5-triphenyl-2-m-chlorophenylimidazol(4g) white solid, mp: 1644-
1
146 ºC. H NMR (600 MHz, DMSO-d ) δ: 7.57-7.62 (m, 16H, Ar-H), 7.39
(m, 2H,Ar-H); IR (KBr): 3017(C-H), 61650(C=C), 1526(Ph), 1233(Ar-H),
1004(Ar-H),877(Ar-H), 768(Ar-H) cm-1.
4,5-bis(3-chlorophenyl)-2-phenyl-1H-imidazole (3d): white solid, mp:
SUPPLEMENTS
282-284 ºC; 1H NMR (600 MHz, DMSO-d6) δ: 12.83 (s, 1H, N-H), 8.08 (d, J
Crystallographic data (CCDC-752970 for 3h) have been deposited at the
1206

J. Chil. Chem. Soc., 57, Nº 3 (2012)
Cambridge Crystallographic Database Centre and crystallographic data for the
structures can be obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[7] G. V. M. Sharma, Y. Jyothi, P. S. LaKSHMI, Syn. Commun. 36, 2991,
(2006).
[8] M. M. Heravi, K. Bakhtiari, H. A. Oskooie, S. Taheri, J. Mol. Catal. A:
Chem. 263, 279, (2007).
ACKNOWLEDGEMENTS
[9] S. A. Siddiqui, U. C. Narkhede, S. S. Palimkar, T. Daniel, R. J. Lahoti, K.
V. Srinivasan, Tetrahedron 61, 3539,. (2005).
This research was supported by the Cultivation and Construction Fund for
the State Key Subject of Physical Chemistry. We thank the Testing Center of
Yangzhou University for characterizing our compounds.
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