Synthesis and biological activities of novel nonpeptide angiotensin II receptor antagonists based on benzimidazole derivatives bearing a heterocyclic ring

Article abstract of DOI:10.1016/j.bmc.2008.10.040

A series of benzimidazole derivatives bearing a heterocyclic ring imidazole (1), 5-chloroimidazole (2), 1,2,4-triazol (3), and imidazoline (4) were synthesized and evaluated for angiotensin II antagonistic activities. The synthetic compounds 1-4 were biologically evaluated in vitro using an AT₁ receptor binding assay, where compounds 1 and 3 provided weak binding affinity, compound 2 showed moderate binding affinity, and compound 4 showed good binding affinity. Moreover, compound 4 was found to be almost equipotent with telmisartan in vivo biological evaluation study.

Full text of DOI:10.1016/j.bmc.2008.10.040

Bioorganic & Medicinal Chemistry 16 (2008) 10301–10310
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis and biological activities of novel nonpeptide angiotensin II
receptor antagonists based on benzimidazole derivatives bearing
a heterocyclic ring
*
Xing-Zhou Guo, Lin Shi, Rui Wang, Xiao-Xiao Liu, Bo-Gang Li, Xiao-Xia Lu
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of benzimidazole derivatives bearing a heterocyclic ring imidazole (1), 5-chloroimidazole (2),
1,2,4-triazol (3), and imidazoline (4) were synthesized and evaluated for angiotensin II antagonistic activ-
ities. The synthetic compounds 1–4 were biologically evaluated in vitro using an AT1 receptor binding
assay, where compounds 1 and 3 provided weak binding affinity, compound 2 showed moderate binding
affinity, and compound 4 showed good binding affinity. Moreover, compound 4 was found to be almost
equipotent with telmisartan in vivo biological evaluation study.
Received 19 September 2008
Revised 16 October 2008
Accepted 17 October 2008
Available online 22 October 2008
Keywords:
Benzimidazole derivatives bearing a
heterocyclic ring
Ó 2008 Elsevier Ltd. All rights reserved.
Nonpeptide angiotensin II receptor
antagonists
Synthesis
Biological activity
1. Introduction
1996, Kohara et al.21 reported the 5-oxo-1,2,4-oxadiazole ring and
its thio analogs are lipophilic bioisosteric replacements for the tet-
Angiotensin II (AngII) is an octapeptide produced by the renin–
angiotensin system (RAS), which plays an important role in the
pathophysiology of hypertension.1,2 This stimulated many
researchers toward designing drugs to block the effects of AngII
either by inhibiting the angiotensin-converting enzyme (ACE) or
renin or by blocking the AngII receptors.3–10 AngII receptor antag-
onists have proved to lower blood pressure effectively,11 and they
are better tolerated than other classes of drugs.12,13 Losartan,14,15
the protypical agent of this category, was served as lead for the
development of newer AngII receptor antagonists.16 Carini et al.17
proposed a structure–activity relationship (SAR) of AT1 receptor
antagonists that suggested activity was improved by the presence
of a biphenyl tetrazole group. In fact, dozens of AT1 receptor antag-
onists share the same biphenyl tetrazole moiety as a common
pharmacophore. However, the tetrazole ring suffers from several
insurmountable drawbacks. The duration of losartan is shortened
partly due to the N-glucoronidation of tetrazole unit in vivo,18–20
and the synthesis of tetrazole can be extremely dangerous as it in-
volves explosive azide compounds. Beside, the existence of tetra-
zole ring also hinders further researches on novel antagonists,
because adding another acidic group to the target molecule, which
is required in many cases, will result in low oral bioavailability. In
razole unit, their derivatives exhibit enhanced activity and oral
bioavailability. Up to now, relatively few studies have been focused
on novel tetrazole replacements, especially groups like heterocy-
clic rings. Thus, we started our investigation of replacement of
the tetrazole ring in AngII receptor antagonists. Besides, the avail-
able data from the literature22 indicated that a benzimidazole
derivative, especially ‘double benzimidazole’, was an excellent
group for good binding affinity. Thus, we wish to report herein
our synthesis, and in vitro and in vivo biological evaluation of
the designed benzimidazole derivatives bearing a heterocyclic ring
(Chart 1).
2. Results and discussion
2.1. Chemistry
The preparation of the target molecule 1 was carried out in six
steps starting from the 2-cyano-40-methylbiphenyl 5 as shown in
Scheme 1. The imidazoline ring was built by cyclization of the ni-
trile with ethylenediamine in the presence of sulfur under solvent-
free condition. Aromatization of imidazoline 6 to the correspond-
ing imidazole 7 has been performed by direct oxidation of 6 by
employing potassium permanganate on silica gel in acetonitrile
at room temperature. Tritylation was followed to give the pro-
tected imidazole 8. The key intermediate 9 was prepared by ben-
* Corresponding author. Tel.: +86 28 85253276; fax: +86 28 85222753.
E-mail address: xlua71@yahoo.com.cn (X.-X. Lu).
0968-0896/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2008.10.040

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X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
CH3
N
Cl
N
N
N
n-Pr
A
Bu
N
N
CH3
HOH2C
N
N
N
N
N
N
NH
N
B
NH
NH
NH
N
N
H
Cl
3
1
4
2
losartan
Chart 1. Our AngII receptor antagonists.
Br
CH3
CH3
CH3
CH3
c
a
N
b
N
d
N
N
CN
N
H
N
H
N
N
Tr
Tr
5
6
7
8
9
CH3
CH3
N
N
N
N
N
N
n-Pr
n-Pr
N
N
e
f
N
NH
N
NTr
CH3
CH3
10
1
Scheme 1. Reagents: (a) NH2CH2CH2NH2, S, reflux; (b) SiO2/KMnO4, CH3CN, rt; (c) Ph3CCl, Et3N, CH2Cl2; (d) NBS, AIBN, CCl4; (e) ‘double benzimidazole’ intermediate 25, NaH,
DMF; (f) HCl, THF.
zylic bromination employing NBS/AIBN. Alkylation of 9 with the
‘double benzimidazole’ intermediate 2-n-propyl-4-methyl-6-(1-
methylbenzimidazol-2-y1)benzimidazole 25 in the presence of so-
dium hydride and dimethylformylamine under mild conditions
provided triphenylmethyl imidazole 10, followed by removal of tri-
phenylmethyl protecting group, provided the target molecule 1.
Scheme 2 demonstrated an alternative and frequently superior
route to the target molecule 1 in which the ‘double benzimidazole’
intermediate 25 was first alkylated with 40-(bromomethyl)-2-
cyanobiphenyl 11 under relatively mild conditions to afford 12.
Likewise, 12 was refluxed with ethylenediamine in the presence
of sulfur to give imidazoline 4, which was further dehydrogenated
by potassium permanganate adsorbed on silica gel to form the tar-
get compound 1. Imidazole 1 could be obtained either from the
deprotection of the trityl imidazole biphenylylmethyl benzimid-
azole derivative 10 or from the corresponding nitrile derivative
12 via imidazoline ring formation. The latter method avoids the
protection and deprotection of imidazole, thus, the entire route is
shortened to four steps and the overall yields are higher. Besides,
the latter method is also fit to prepare imidazoline derivative 4.
As shown in Scheme 3, the chloro-substituted imidazole 2 was
synthesized starting from the 2-cyano-40-methylbiphenyl 5, alka-
line hydrolysis of 5 in refluxing ethylene glycol for 20 h provided
the biphenylcarboxylic acid 13.23 This acid was converted, through
its acid chloride, to the N-acylated a-aminonitrile 14. The treat-
ment of compound 14 with 1.0 equiv of triphenylphosphine and
1.0 equiv of carbon tetrachloride at 45 °C in acetonitrile gradually
generated 5-chloroimidazole product 15 in 80.2% isolated yield.
Tritylation, benzylic bromination, alkylation, and deprotection, as
described for the imidazole derivative 1 via method I, afforded 2.
1,2,4-Triazole derivative 3 was prepared in Scheme 4. Conver-
sion of 5 to the thioamide 19 was performed at room temperature
with 70% sodium hydrogen sulfide hydrate and magnesium chlo-
ride hexahydrate in dimethylformaide (DMF). Treatment of 19
with methyl iodide gave the activated intermediate 20, which
was elaborated to the 1,2,4-triazole compound 21 by treatment
with formic hydrazide in dimethylformamide at elevated temper-
ature. Compound 21 was protected as the trityl derivative 22 and
converted to the bromo compound 23. Reaction of 23 with the
‘double benzimidazole’ intermediate 25 was then carried out using
the conditions described in Scheme 1, followed by removal of tri-
phenylmethyl protecting group, provided the target molecule 3.
2.2. Biological evaluation
2.2.1. Angiotensin II receptor (AT1)-binding assay
The prepared compounds 1–4 were evaluated for their activity
to competitively inhibit [125I]AngII binding to the AT1 receptor by a

X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
10303
CH3
Br
N
CH3
N
n-Pr
N
N
CH3
CN
a
b
c
CN
N
CN
12
11
5
CH3
CH3
N
N
N
N
n-Pr
n-Pr
d
N
N
CH3
N
CH3
N
NH
N
NH
1
4
Scheme 2. Reagents: (a) NBS, AIBN, CCl4; (b) ‘double benzimidazole’ intermediate 25, NaH, DMF; (c) NH2CH2CH2NH2, S, reflux; (d) SiO2/KMnO4, CH3CN.
Br
CH3
CH3
CH3
CH3
CH3
CN
N
a
b
HN
N
d
N
e
Cl
c
Cl
Cl
CN
COOH
N
N
H
N
O
Tr
Tr
13
16
5
14
15
17
CH3
CH3
N
N
N
N
N
N
N
N
n-Pr
n-Pr
Cl
Cl
g
f
N
NH
N
Ntr
CH3
CH3
2
18
Scheme 3. Reagents: (a) NaOH/HOCH2CH2OH; (b) SOCl2/CHCl3, then NaOH, H2NCH2CN; (c) PPh3, CCl4; (d) Ph3CCl, Et3N, CH2Cl2; (e) NBS, AIBN, CCl4; (f) ‘double benzimidazole’
intermediate 25, NaH, DMF; (g) HCl, THF.
conventional ligand-binding assay using a bovine adrenal cortex.24
The results are expressed as IC50 values and are listed in Table 1.
The heterocyclic ring, imidazole derivative 1 and 1,2,4-triazoles
derivative 3 were found to have very similar IC50 values. They
are relatively nonacidic and as a result do not possess good binding
affinities. The acidity of imidazole can be increased through substi-
tution by electron-withdrawing group, such as Cl. With regard to
5-chloroimidazole derivative 2, the binding affinity surpasses
those of the corresponding imidazole derivative 1. Unfortunately
these groups still were not acidic enough to allow for proper bind-
ing to the AngII receptor. More interestingly, imidazoline deriva-
tive 4 was found to be as potent as the losartan.
addition of the angiotensin II receptor antagonist. Potent inhibition
of the pressor response induced by AngII of each test compound
was evaluated by extent of increase in blood pressure after 1 h oral
administration of the test compounds and intravenous administra-
tion of AngII in conscious Beagle dogs (Fig. 1). The smaller of extent
of increase in blood pressure, the more potency in vivo of the test
compound. The blood pressure (BP) and heart rate after 1 h treat-
ment with the test compounds (2.13 mg/kg, po) and AngII
(0.45 lg/kg, iv) were recorded and the data are listed in Tables
2–5. With respect to the heterocyclic ring, the imidazoline deriva-
tive 4 which exhibited the highest binding affinities of this series,
were also the most potent compounds in vivo. Compound 4 caused
significant reduction in conscious Beagle dogs almost approach to
the standard drug telmisartan. This suggests that compound 4 is an
orally active AT1 receptor antagonist. The poor in vitro activity of
the imidazole derivative 1 and the 1,2,4-triazole 3 was also con-
firmed in vivo. The 5-chloro-substituted imidazole compound 2
displayed stronger potencies than those of the unsubstituted imid-
2.2.2. Antagonism of AngII-induced pressor response by oral
administration in the spontaneously hypertensive dogs
Intravenous administration of angiotensin II (AngII) will stimu-
late angiotensin II receptor and increase blood pressure. This pres-
sor effect was reversed, with a markedly lowered pressure by

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X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
Br
CH3
CH3
CH3
CH3
CH3
N
S
N
N
a
NH2
S
e
c
b
d
NTr
NH
NTr
CN
N+H2I-
N
N
N
20
21
22
19
5
23
CH3
CH3
N
N
N
N
N
n-Pr
N
N
n-Pr
N
NTr
N
CH3
N
NH
g
f
N
N
CH3
24
3
Scheme 4. Reagents: (a) 70%NaSH, MgCl3ꢀ6H2O, DMF; (b) CH3I, ether; (c) NH2NH2CHO, DMF; (d) Ph3CCl, Et3N, CH2Cl2; (e) NBS, AIBN, CCl4; (f) ‘double benzimidazole’
intermediate 25, NaH, DMF; (g) HCl, THF.
Table 1
ical activities as
a novel class of nonpeptide AT1 receptor
AT1 receptor binding affinities of compounds 1–4.
antagonists. As demonstrated by in vitro and in vivo results, the
imidazoline derivative 4, displayed almost equal antihypertensive
activity to that of the reference compound (telmisartan), whereas
the imidazole derivatives 1, 2 and the triazole derivative 3 showed
weak or no antihypertensive activity. We believe that compound 4
has interesting pharmacological properties and can be applied to
modification of other antihypertensive drugs. Further work on
compound 4 is in progress.
Compound
Receptor affinity IC50,10ꢁ7 Ma
1
2
3
4
14
6.8
15
2.9
Losartan
Telmisartan
1.6, 1.5b, 1.2c, 0.064d
ꢂ0.01d
Inhibition of specific binding of [125I]AII (0.2 nM) to bovine adrenal cortex. The
a
IC50 value is the concentration of compound which inhibits [125I]AII binding by 50%.
b
4. Experimental
4.1. General
Data taken from Ref. 21.
Data taken from Ref. 25.
Data taken from Ref. 7.
c
d
The melting points were measured in an X-6 melting point
apparatus and were uncorrected. 1H and 13C {1H} NMR spectra
azole derivative 1, in agreement with their binding affinities. Fur-
thermore, the tested compound except 1,2,4-triazole compound
3 all produced decrease in the basal heart rate.
were recorded on
a Bruker Avance 600 NMR spectrometer
(600 MHz for 1H, and 150 MHz for 13C) in CDCl3 at 298 K. Chemical
shifts (in ppm) of 1H and 13C{1H} NMR spectra were recorded rel-
ative to tetramethylsilane (Me4Si). Mass spectra were obtained on
a Finnigan-LCQDECA mass spectrometer (ESI-MS) and ESI-HRMS
spectra were recorded on BioTOF Q. Elemental analyses of the
new complexes were performed on a Carlo Erba 1106 elemental
3. Conclusion
The present study describes the synthesis of a series of benz-
imidazole derivatives bearing a heterocyclic ring and their biolog-
200
180
160
140
120
100
80
Effects of drug according to extent
of increase in blood pressure
Figure 1. Effect of dosing test compounds on blood pressure and heart rate in Beagle dogs.

X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
10305
Table 2
Effects of compounds 1–4 and telmisartan on AngII-induced mean systolic blood pressure in conscious normotensive Beagle dogs.
Compound
na
Mean systolic blood pressure SEM rate of change
Before making modelb
Normal
After making modelc
Control
7
6
6
6
6
7
117.60 21.92
100%
123.32 17.07
100%
141.82 23.04
100%
127.36 23.76
100%
126.82 22.04
100%
125.87 20.63
100%
126.96 21.07
108.69 11.47
120.50 8.40
98.67 9.34
135.94 29.22
95.75 11.22
130.79 17.51
103.80 8.73
121.94 23.22
96.75 11.22
120.33 21.56
95.78 11.09
179.42 28.40##
154.11 20.42
184.04 33.80
##
1
151.55 33.31
191.75 45.01#
135.49 22.74
2
##
3
183.44 21.87
149.11 37.29
134.75 22.01#
112.49 14.74*
134.87 20.06
107.88 12.29**
4
Telmisartan
a
n is the number of animals treated.
Blood pressure values after 1 h oral administration of the test compounds (2.13 mg/kg po).
b
c
Blood pressure values after 1 min of intravenous administration of AngII (0.45
p < 0.05 versus interclass applying observed values, statistically significant.
p < 0.01 versus interclass applying observed values, statistically significant.
p < 0.05 versus control applying rate of change values, statistically significant.
p < 0.01 versus control applying rate of change values, statistically significant.
lg/kg, iv).
#
##
*
**
Table 3
Effects of compounds 1–4 and telmisartan on AngII-induced mean diastolic blood pressure in conscious normotensive Beagle dogs.
Compound
na
Mean diastolic blood pressure SEM rate of change
Before making modelb
Normal
After making modelc
Control
7
6
6
6
6
7
89.23 15.40
100%
87.82 17.98
100%
101.69 20.43
100%
94.63 21.08
100%
96.69 20.43
100%
95.52 23.85
100%
97.87 21.14
109.35 12.43
85.20 16.65
97.96 12.61
95.891 8.64
95.28 12.32
96.33 16.77
103.14 9.65
91.09 8.64
137.71 17.83##
156.28 19.25
132.02 21.25##
156.09 41.98
133.61 23.76#
133.37 20.11
136.17 16.23##
151.10 41.80
98.61 23.76#
107.37 20.11*
94.02 13.97
1
2
3
4
95.28 12.32
90.66 20.95
96.15 13.89
Telmisartan
103.12 26.25**
For explanation of footnotes see Table 1.
Table 4
Effect of compounds 1–4 and telmisartan on mean arterial blood pressure in conscious normotensive Beagle dogs.
Compound
na
Mean Arterial Blood Pressure SEM rate of change
Before making modelb
Normal
After making modelc
Control
7
6
6
6
6
7
98.69 16.84
100%
99.65 16.65
100%
115.06 20.86
100%
105.54 21.51
100%
106.06 20.86
100%
105.39 22.00
100%
107.57 20.31
109.11 11.94
96.86 13.18
98.11 10.71
109.24 21.68
95.43 11.39
107.82 16.70
103.37 9.23
102.24 21.68
97.43 11.39
100.55 20.53
96.13 12.92
151.61 19.38##
155.44 19.19
149.31 23.06##
154.06 37.8
1
2
153.03 29.38#
134.26 19.69
151.93 17.78##
150.17 39.84
116.53 29.38#
114.26 19.69*
107.64 15.51
104.88 20.58**
3
4
Telmisartan
For explanation of footnotes see Table 1.
analyzer at the Chengdu Institute of Organic Chemistry, Chinese
Academy of Sciences. Column chromatography (CC) was carried
out on silica gel (200–300 mesh, Qingdao Haiyang Chemical Group
Co., China). Thin-layer chromatography (TLC) over silica gel 60H
(Qingdao Haiyang Chemical Group Co., China) precoated plates.
All air-sensitive reactions were conducted in flame- or oven-dried
apparatus under a positive pressure of nitrogen. When necessary,
solvents and reagents were dried prior to use. Tetrahydrofuran
(THF) was distilled from sodium metal/benzophenone ketyl.
Dichloromethane was distilled from calcium hydride, and chloro-
form was passed through an alumina column. Most reagents were
purchased from Lancaster and Aldrich. Pentobarbital sodium and
telmisartan were kindly provided by the Sichuan Kelun Pharma-
ceutical, Sinopharm Chemical Reagent Co. Ltd, and Shangxi Chu-

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X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
Table 5
Effect of compounds 1–4 and telmisartan on mean heart rate in conscious normotensive Beagle dogs.
Compound
na
Mean heart rate SEM rate of change
Before making modelb
Normal
After making modelc
Control
7
6
6
6
6
7
144.60 33.73
100%
150.85 37.41
100%
174.37 29.72
100%
151.54 52.13
100%
171.37 29.72
100%
167.66 37.67
100%
149.28 40.36
100.75 8.38
129.80 34.41
86.20 8.24*
142.57 17.94
82.40 6.37**
139.94 48.15
93.29 15.88
155.57 17.94
84.40 6.37*
145.87 39.65
86.00 11.28*
152.03 29.53
105.21 17.14
145.55 23.42
98.87 15.43
149.80 15.40
87.68 14.73
152.31 39.51
103.18 14.32
149.80 15.40
94.68 14.73
150.66 23.22
92.67 17.18
1
2
3
4
Telmisartan
a
n is the number of animals treated.
Heart rate values after 1 h oral administration of the test compounds (2.13 mg/kg po).
Heart rate values after 1 min of intravenous administration of AngII (0.45 g/kg, iv).
p < 0.05 versus telmisartan applying rate of change values, statistically significant.
p < 0.01 versus telmisartan applying rate of change values, statistically significant.
b
c
l
*
**
anglong Pharmaceutical Co. Ltd, separately. AngII was purchased
from Sigma. 2-Cyano-40-methylbiphenyl (5) was purchased from Al-
drich. Preparation of 40-methylbiphenyl-2-carboxylic acid (13)23
2H), 7.16–7.17 (d, J = 7.92, 2H), 7.19–7.21 (d, J = 7.92, 2H),
7.27–7.28 (d, J = 7.02 Hz, 1H), 7.36–7.41 (m, 2H), 8.07–8.08 (d,
J = 7.32 Hz, 1H), 8.57 (s, 1H). 13C NMR (150 MHz, CDCl3): d
21.21, 127.77, 128.45, 128.85, 129.07, 129.49, 129.57, 130.62,
137.64, 138.13, 139.08, 146.21; MS (ESI+) m/z 235.1 (MH+). Ana-
l.Calcd for C16H14N2: C, 82.02; H, 6.02; N, 11.96. Found: C, 82.08;
H, 6.05; N, 11.91.
and
2-n-Propyl-4-methyl-6-(1-methylbenzimidazol-2-y1)benz-
imidazole (25)22 were performed according to reported procedures.
4.2. Synthesis
4.2.1. Synthesis of 40-{[2-n-propyl-4-methyl-6-(1-methylbenzoi-
midazol-2-yl)benzoimidazol-1-yl]methyl}-2-(1H-imidazole-2-yl)
biphenyl (1)
4.2.1.3. 1-Triphenylmethyl-2-(40-methylbiphenyl-2-yl)-1H-
imidazole (8). This was prepared according to a modified meth-
od.15 To a solution of compound 7 (2.34 g, 0.01 mol) in CH2Cl2
(40 mL) was added triethylamine (8 mL). After stirring for 30 min
at room temperature, triphenylmethyl chloride (2.79 g, 10 mmol)
was added and the mixture was stirred for another 3–4 h. After
the evaporation of the solvent, the residue was dissolved in ethyl
acetate, washed with solution of NaOH (1N) and dried over anhy-
drous magnesium sulfate. The crude product was purified by Al2O3
column chromatography eluting with petroleum ether/ethyl ace-
tate (1:3) to provide 8 as a white solid (3.62 g, 75.9%). Mp 198.5–
200 °C; 1H NMR (600 MHz, CDCl3): d 2.44 (s, 3H), 6.41 (s, 1H),
6.62–6.63 (d, J = 7.92 Hz, 6H), 6.91–6.93 (m 3H), 6.97–7.00 (t,
J = 7.74 Hz, 6H), 7.03-7.05 (t, J = 7.47 Hz, 1H), 7.07–7.08 (d,
J = 8.04 Hz, 2H), 7.09–7.14 (m, 5H), 7.14–7.16 (t, J = 6.54 Hz, 1H);
13C NMR (150 MHz, CDCl3): d 21.1, 125.3, 126.1, 126.9, 127.3,
128.4, 129.4, 130.3, 130.7, 131.8, 133.2, 136.3, 137.8, 141.4,
142.3, 148.2; MS (ESI+) m/z 477.1 (MH+). Anal. Calcd for
C35H28N2: C, 88.20; H, 5.92; N, 5.88. Found: C, 88.23; H, 5.89; N,
5.86.
4.2.1.1. 2-(40-Methylbiphenyl-2-yl)-1H-imidazoline
(6). This
was prepared according to a modified method.26 A mixture of 2-cy-
ano-40-methylbiphenyl
(15.5 g, 0.08 mol), ethylenediamine
5
(21.5 mL, 0.32 mol), and sulfur (0.64 g, 0.02 mol) was refluxed on
an oil bath (120 °C). The progress of the reaction was monitored
by TLC (eluent: EtOAc/MeOH, 4:1). After completion of the reac-
tion, the mixture was cooled to room temperature and cold water
was added. The reaction mixture was extracted with chloroform
and the organic layer was dried over anhydrous sodium sulfate.
The solvent was evaporated and the crude was recrystallized from
cyclohexane to afford the pure product 6 (16.0 g, 84.8 %). Mp
109.5–110 °C; 1H NMR (600 MHz, CDCl3): d 2.41 (s, 3H), 3.79 (s,
4H), 6.04 (s, 1H), 7.15–7.16 (d, J = 7.82 Hz, 2H), 7.21–7.22 (d,
J = 7.82 Hz, 2H), 7.32–7.33 (d, J = 7.05 Hz, 1H), 7.35–7.40 (m, 2H),
8.02–8.03 (d, J = 7.32 Hz, 1H); 13C NMR (150 MHz, CDCl3): d 21.3,
49.8, 50.7, 125.5, 127.8, 128.7, 128.8, 130.6, 134.5, 135.2, 136.0,
137.3, 156.8; MS (ESI+) m/z 237.1 (MH+). Anal. Calcd for
C16H16N2: C, 81.32; H, 6.82; N, 11.85. Found: C, 81.38; H, 6.77; N,
11.83.
4.2.1.4. 1-Triphenylmethyl-2-[40-(bromomethyl)biphenyl-2-yl]-
1H-imidazole (9). This was prepared according to a modified
method.15 A solution of compound 8 (3.10 g, 6.5 mmol), N-brom-
oeuccinimide (1.15 g, 6.5 mmol), and dibenzoyl peroxide (0.11 g,
0.45 mmol) in carbon tetrachloride (40 mL) was refluxed for 3 h,
cooled to 40 °C, and then filtered. The filtrate was concentrated un-
der vacuum to afford the crude product 9. The crude product is
routinely used without further purification.
4.2.1.2. 2-(40-Methylbiphenyl-2-yl)-1H-imidazole (7). This was
prepared according to
a 6
modified method.27 Compound
(4.72 g, 0.02 mol) was dissolved in acetonitrile (250 mL), grinded
potassium permanganate (7.9 g, 0.05 mol), and silica gel (10 g)
were added to the solution in portions. The course of the reac-
tion was monitored by TLC (eluent: EtOAc/MeOH, 4:1). After
completion of the reaction, 10 mL of ethanol was added, and
then the mixture was filtered and the precipitated solid was
washed with acetonitrile (200 mL). The filtrate was combined
and concentrated under vacuum, the residue was purified by
Al2O3 column chromatography eluting with petroleum ether/
EtOAc (1:2) to give the pure product (3.35 g, 71.5%). Mp 176.5–
177.4 °C; 1H NMR (600 MHz, CDCl3): d 2.39 (s, 3H), 6.89 (s,
4.2.1.5. 40-{[2-n-Propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(1-triphenylmethylimidaz-
ole-2-yl)biphenyl (10). This was prepared according to a modi-
fied method.15 To a solution of compound 25 (2.37 g, 7.44 mmol)
in 20 mL of DMF was added NaH (0.65 g) at 0 °C. After stirring for
1 h at ambient temperature, a solution of compound 9 (3.61 g,

X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
10307
6.5 mmol) in DMF (10 mL) was added and the stirring continued
for about 25 h. Following the addition of water (20 mL), the
resulting solution was extracted with ethyl acetate (3ꢃ 20 mL),
dried over anhydrous Na2SO4 and evaporated under vacuum.
The crude product was purified by Al2O3 column chromatography
(eluant: petroleum ether/ethyl acetate 1:3 and 1:10) to provide
product 10 as a light yellow solid (1.56 g, 30.8%). Mp 203.7–
205.1 °C; 1H NMR (600 MHz, CDCl3): d 1.06–1.09 (t, J = 7.44 Hz,
3H), 1.89–1.93 (m, 2H), 2.79 (s, 3H), 2.96–2.98 (t, J = 7.89 Hz,
2H), 3.74 (s, 3H), 5.45 (s, 2H), 6.41–6.42 (d, J = 1.5 Hz, 1H),
6.67–6.68 d, J = 7.92 Hz, 6H), 6.89–6.90 (d, J = 7.92 Hz, 1H),
6.93–6.94 (t, J = 7.80 Hz, 6H), 6.97–6.99 (m, 5H), 7.01–7.07 (m,
5H), 7.10–7.13 (m, 1H), 7.29–7.36 (m,4H), 7.45 (s, 1H), 7.55 (s,
1H), 7.80–7.81 (m, 1H); 13C NMR (150 MHz, CDCl3): d 14.2,
16.9, 21.8, 29.8, 31.9, 47.5, 78.7, 109.4, 119.3, 122.5, 122.7,
123.4, 125.9, 126.6, 127.8, 128.1, 128.9, 129.4, 129.8, 130.0,
134.4, 135.1, 136.6, 140.8, 142.0, 142.6, 143.3, 145.8, 154.8,
156.8, 162.3; MS (ESI) m/z 780.1 (MH+). Anal. Calcd for
C54H46N6: C, 83.26; H, 5.95; N, 10.79. Found: C, 83.31; H, 5.89;
N, 10.73.
7.45–7.46 (m, 2H), 7.62–7.93 (d, J = 8.04 Hz, 1H), 7.95–7.96 (m,
1H), 8.03 (s, 1H); 13C NMR (150 MHz, CDCl3): d 14.1, 16.8, 24.3,
29.2, 32.9, 50.4, 104.6, 109.2, 110.3, 111.2, 117.1, 119.5, 122.5,
123.6, 123.9, 126.4, 127.8, 128.2, 128.5, 129.3, 132.7, 133.6,
134.5, 134.7, 136.4, 138.4, 142.5, 142.8, 153.2, 154.9; MS (ESI) m/
z 496.5 (MH+). Anal. Calcd for C33H29N5: C, 79.97; H, 5.90; N,
14.13. Found: C, 80.10; H, 5.95; N, 14.03.
4.2.2.3. 40-{[2-n-propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(1H-imidazoline-2-yl)biphenyl
(4). The title compound 4 was prepared from compound 12 using
the procedure described in the preparation of compound 6. Com-
pound 4 (80.2%, yield). Mp 98.7–99.9 °C; 1H NMR (600 MHz,
CDCl3): d 1.02–1.05 (t, J = 7.35 Hz, 3H), 1.84–1.88 (m, 2H), 2.77 (s,
3H), 2.91–2.93 (t, J = 7.83 Hz, 2H), 3.46 (s, 4H), 3.85 (s, 3H), 5.39
(s, 2H), 6.78–7.80 (d, J = 7.98 Hz, 2H), 6.82–6.84 (t,
J = 7.26 Hz,1H), 7.07–7.09 (d, J = 7.92 Hz, 2H), 7.14–7.17 (t,
J = 7.74 Hz, 1H), 7.27–7.32 (m, 1H), 7.34–7.35 (d, J = 7.92 Hz, 2H),
7.37–7.39 (s, 1H), 7.43–7.46 (t, J = 7.65 Hz, 1H), 7.50 (s, 1H),
7.71–7.75 (dd, J = 10.92, 7.56 Hz, 2H); 13C NMR (150 MHz, CDCl3):
d 14.2, 17.0, 22.0, 29.9, 31.9, 47.3, 50.8, 109.6, 109.5, 119.3, 122.6,
122.8, 123.4, 123.7, 126.7, 128.2, 128.7, 129.3, 129.6, 129.9, 130.4,
135.0, 135.1, 136.5, 138.6, 140.7, 142.4, 143.4, 145.7, 154.8, 157.0;
ESI-HRMS: m/z calcd for [C35H35N6]+: 539.6928; found 539.3076.
Anal. calcd for C35H34N6: C, 78.04; H, 6.36; N, 15. 60. Found: C,
77.30; H, 6.55; N, 15.93.
4.2.1.6. 40-{[2-n-propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(1H-imidazole-2-yl)biphenyl
(1). This was prepared according to a modified method.15 To a
solution of compound 10 (1.00 g, 1.28 mmol) in tetrahydrofuran
(25 mL) was added hydrochloric acid (10%, 12.5 mL). After stirring
for about 8 h, an excess of aqueous NaOH (10%) was added. The sol-
vent was removed in vacuo, then the resulting solid was washed
with chloroform and the organic layers were combined. Following
the concentration, the crude product was purified by silica gel col-
umn chromatography (eluant: chloroform/methanol 12:1) to af-
ford the title compound 1 (0.62 g, 90.2%). Mp 143.7–145.1 °C; 1H
NMR (600 MHz, CDCl3): d 1.06–1.09 (t, J = 7.23 Hz, 3H), 1.86–1.91
(m, 2H), 2.78 (s, 3H), 2.95–2.97 (t, J = 7.86 Hz, 2H), 3.87 (s, 3H),
5.41 (s, 2H), 6.68–6.69 (d, J = 8.34 Hz, 1H), 7.03–7.05 (d,
J = 8.04 Hz, 2H), 7.20–7.21 (d, J = 7.98 Hz, 2H), 7.28–7.33 (m, 4H),
7.39–7.45 (m, 4H), 7.66–7.67 (d, J = 8.04 Hz, 1H), 7.95–7.96 (m,
2H), 9.56 (s 1H); 13C NMR (150 MHz, CDCl3): d 14.1, 17.0, 21.8,
29.9, 31.9, 47.3, 109.5, 109.6, 119.3, 122.5, 122.7, 123.4, 123.7,
126.6, 128.1, 128.8, 129.4, 129.5, 129.9, 130.3, 135.0, 135.1,
136.5, 138.6, 140.8, 142.5, 143.3, 145.8, 154.6, 156.6; ESI-HRMS:
m/z calcd for [C35H33N6]+: 537.6770; found: 537.2761. Anal. Calcd
for C35H32N6: C, 78.33; H, 6.01; N, 15.66. Found: C, 78.40; H, 5.95;
N, 15.63.
4.2.2.4. 2-[40-[4-methyl-6-(1-methyl-benzoimidazol-2-yl)-2-pro-
pyl-benzoimidazol]-1-yl]methylbiphenyl-2-yl]-1H-imidazole
(1). The title compound 1 was prepared from compound 4 using
the procedure described in the preparation of compound 7. Com-
pound 1 (66.2%, yield). Mp 143.9–144.8 °C; 1H NMR (600 MHz,
CDCl3): d 1.06–1.09 (t, J = 7.23 Hz, 3H), 1.86–1.91 (m, 2H), 2.78 (s,
3H), 2.95–2.97 (t, J = 7.86 Hz, 2H), 3.87 (s, 3H), 5.41 (s, 2H), 6.68–
6.69 (d, J = 8.34 Hz, 1H), 7.03–7.05 (d, J = 8.04 Hz, 2H), 7.20–7.21
(d, J = 7.98 Hz, 2H), 7.28–7.33 (m, 4H), 7.39–7.45 (m, 4H), 7.66–
7.67 (d, J = 8.04 Hz, 1H), 7.95–7.96 (m, 2H), 9.56 (s 1H).
4.2.3. Synthesis of 40-{[2-n-propyl-4-methyl-6-(1-methylbenzo-
imidazol-2-yl)benzoimidazol-1-yl]methyl}-2-(5-chloro-1H-
imidazole-2-yl)biphenyl (2)
4.2.3.1. N-(2-cyanomethyl)-40-methylbiphenyl-2-carboxamide
(14). This was prepared according to a modified method.15
A
solution of 40-methylbiphenyl-2-carboxylic acid 13 (5.0 g,
23.6 mmol), thionyl chloride (8.75 mL, 0.12 mol), and 50 mL of
chloroform was refluxed for 4 h. The solvent was removed under
vacuum, and the residue was concentrated twice from toluene to
remove traces of thionyl chloride. The acid chloride thus obtained
was dissolved in 25 mL of tetrahydrofuran. This solution was
added dropwise in five equal portions, alternating with five equal
portions of 1.0 N aqueous sodium hydroxide (23.6 mL,
23.6 mmol), into a solution of 2-aminoacetonitrile hydrochloride
(2.16 g, 23.6 mmol) in 1.0 N aqueous sodium hydroxide
(23.6 mL, 23.6 mmol) at 0 °C. After 12 h at 25 °C, water (25 mL)
was added, and the mixture was extracted with ethyl acetate
(3ꢃ 50 mL). The organic layers were collected, dried over anhy-
drous magnesium sulfate, and filtered, and the solvent was re-
moved under vacuum. The residue was recrystallized from
methylcyclohexane to furnish 14 as a white solid (5.08 g, 86%).
Mp 101.0–102.0 °C; 1H NMR (600 MHz, CDCl3): d 2.37 (s, 3H),
4.66 (s, 2H), 5.65 (br, 1H), 7.12 (d, J = 7.80 Hz, 2H), 7.40–7.37 (t,
J = 7.85 Hz, 2H), 7.62–7.54 (m,3H), 8.10 (m, 1H); 13C NMR
(150 MHz, CDCl3): d 24.3, 31.6, 114.8, 127.8, 128.0, 129.5, 131.9,
132.1, 132.7, 133.5, 137.3, 167.6; MS (ESI) m/z 251.0 (MH+). Anal.
Calcd for C16H14N2O: C, 76.78; H, 5.64; N, 11.19. Found: C, 76.40;
H, 5.95; N, 11.23.
4.2.2. Synthesis of 40-{[2-n-propyl-4-methyl-6-(1-methylbenzo-
imidazol-2-yl)benzoimidazol-1-yl]methyl}-2-(1H-imidazoline-
2-yl)biphenyl (4) and40-{[2-n-propyl-4-methyl-6-(1-methylben-
zoimidazol-2-yl)benzoimidazol-1-yl]methyl}-2-(1H-imidazole-
2-yl)biphenyl (1)
4.2.2.1. 2-Cyano-40-bromomethylbiphenyl (11). The title com-
pound 11 was prepared from 2-cyano-40-methylbiphenyl
5
using the procedure described in the preparation of compound
9. The crude product is routinely used without further
purification.
4.2.2.2. 40-{[2-n-propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-cyanobiphenyl (12). The title
compound 12 was prepared from 2-cyano-40-bromomethylbiphe-
nyl 11 using the procedure described in the preparation of com-
pound 10. Compound 12 (60.3%, yield). Mp 181.2–182.1 °C; 1H
NMR (600 MHz, CDCl3): d 1.08–1.00 (t, J = 7.32 Hz, 3H), 1.89–1.93
(m, 2H), 2.76 (s, 3H), 3.01–3.03 (t, J = 7.71 Hz, 2H)), 3.79 (s, 3H),
5.43 (s, 2H), 6.93–6.94 (d, J = 7.62 Hz, 2H), 7.12–7.14 (d,
J = 8.22 Hz, 2H), 7.20 (s, 1H), 7.24–7.26 (m, 1H), 7.30–7.33 (d,
J = 7.62 Hz, 1H), 7.39–7.40 (d, J = 7.98 Hz, 1H), 7.42–7.43 (m, 1H),

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X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
4.2.3.2. 2-(40-Methylbiphenyl-2-yl)-5-chloroimidazole (15). This
was prepared according to a modified method.28 A solution of
compound 14 (3.75 g, 15 mmol) and triphenylphosphine
(9.82 g, 37.5 mmol) in acetonitrile (150 mL) was treated with
carbon tetrachloride (5.78 g, 37.5 mmol) at 45 °C for 16 h. The
reaction mixture was concentrated and the residue was dis-
solved in 150 mL methylene chloride. To the solution was added
0.5 N sodium hydroxide (150 mL), the two-phase mixture was
stirred at room temperature for 10 min. After phase separation,
the organic layer was washed with water (2ꢃ 60 mL), brine
(60 mL), and concentrated, the residue was purified by flash
chromatography (silica gel, hexane/CHCl3/EtOAc = 10:2:1) to give
desired product 15 (3.23 g, 80.2%). Mp 171.9–173.2 °C; 1H NMR
(600 MHz, CDCl3): d 2.42 (s, 3H), 6.66 (s, 1H), 7.20–7.22 (d,
J = 7.68 Hz, 2H), 7.25–7.28 (m, 3H), 7.39–7.44 (m, 2H), 8.13–
8.15 (d, J = 7.74 Hz, 1H), 8.17 (s, 1H); 13C NMR (150 MHz, CDCl3):
d 21.3, 112.2, 127.6, 127.9, 128.9, 129.1, 129.4, 129.8, 130.7,
137.7, 138.1, 138.8, 145.0; MS (ESI) m/z 269.0 (MH+). Anal. Calcd
for C16H13ClN2: C, 71.51; H, 4.88; N, 10.42; Cl, 13.19. Found: C,
71.53; H, 4.89; N, 10.40; Cl, 13.20.
2H), 7.57–7.58 (m, 1H), 7.89–7.90 (m,1H), 9.88 (s, 1H); 13C NMR
(150 MHz, CDCl3): d 13.5, 19.8, 24.5, 29.6, 47.2, 58.3, 110.9,
115.4, 122.6, 123.8, 124.4, 126.8, 128.4, 129.5, 133.4, 133.8,
134.0, 135.5, 135.6, 138.4, 138.5, 141.8, 153.5, 153.3, 154.7; ESI-
HRMS: m/z calcd for [C35H32ClN6]+: 571.1138; found: 571.3809.
Anal. Calcd for C35H31ClN6: C, 73.61; H, 5.47; Cl, 6.21; N, 14.72.
Found: C, 73.40; H, 5.45; Cl, 6.18; N, 14.63.
4.2.4. Synthesis of 40-{[2-n-propyl-4-methyl-6-(1-methylbenzo-
imidazol-2-yl)benzoimidazol-1-yl]methyl}-2-(1H-1,2,4-triazol-
3-yl)biphenyl (3)
4.2.4.1. 4-Methyl-20-thiocarboxamido-1,10-biphenyl (19). This
was prepared according to a modified method.29 To a slurry of
70% sodium hydrosulfide hydrate (7.9 g, 99 mmol) and magnesium
chloride hexahydrate (10.1 g, 50 mmol) in 100 mL of DMF was
added 2-cyano-40-methylbiphenyl 5 (9.6 g, 50 mmol) in one por-
tion, and the mixture was stirred at room temperature for 2 h.
The resulting green slurry was poured into 200 mL water, and
the resulting precipitates were collected by filtration. The crude
product was resuspended in 1 N HCl and stirred for 20 min, then
filtered and washed with water to give the title compound 19
(10.47 g, 92.1%). Mp 135.5–136.7 °C; 1H NMR (600 MHz, CDCl3): d
2.41 (s, 3H), 6.48 (br s, 2H), 7.32 (m, 7H), 7.91 (dd, J = 9.86,
2.34 Hz, 2H); MS (ESI) m/z 228.3 (MH+).
4.2.3.3. 1-Triphenylmethyl-2-(40-methylbiphenyl-2-yl)-5-chloro-
1H-imidazole (16). The title compound 16 was prepared from
compound 15 using the procedure described in the preparation
of compound 8. Compound 16 (76.2%, yield). Mp 154.8–156.2 °C;
1H NMR (600 MHz, CDCl3): d 2.46 (s, 3H), 6.28 (s, 1H), 6.60–6.61
(d, J = 7.62 Hz, 6H), 6.91–6.93 (t, J = 7.26 Hz, 3H), 6.98–7.01 (t,
J = 7.74 Hz, 6H), 7.05–7.07 (t, J = 7.17 Hz, 1H), 7.11–7.17 (m, 7H);
13C NMR (150 MHz, CDCl3): d 21.2, 78.7, 120.5, 126.1,127.0,
127.5, 127.9, 128.6, 128.9, 129.1, 129.5, 130.4, 130.6, 131.7,
136.5, 137.5, 141.6, 147.2; MS (ESI) m/z 512.0 (MH+). Anal. Calcd
for C35H27ClN2: C, 82.26; H, 5.32; N, 5.48; Cl, 6.94. Found: C,
82.53; H, 5.39; N, 5.40; Cl, 6.88.
4.2.4.2. 4-Methyl-20-isothiocarboximino-1,10-biphenyl, methio-
dide (20). This was prepared according to a method.30 A solution
of
4-methyl-20-thiocarboxamido-1,10-biphenyl
19
(2.0 g,
8.8 mmol) in 80 mL of ethyl ether was treated with iodomethane
(4.0 mL, 64 mmol). After stirring at room temperature for 24 h,
the reaction mixture was filtered. The precipitate was washed with
ether (3ꢃ 10 mL) and dried under vacuum to give the title com-
pound 20 (2.71 g, 83.5%). Mp 165.7–169.1 °C (dec); 1H NMR
(600 MHz, CDCl3): d 2.41 (s, 3H), 6.48 (br s, 2H), 7.3 (m, 7H), 7.9
(dd, J = 7.86 Hz, 2H); MS (ESI) m/z 242.1 (M+).
4.2.3.4. 1-Triphenylmethyl-2-(40-bromomethylbiphenyl-2-yl)-
5-chloro-1H-imidazole (17). The title compound 17 was pre-
pared from compound 16 using the procedure described in the
preparation of 9. The crude product is routinely used without fur-
ther purification.
4.2.4.3. 4-Methyl-20-(1H-1,2,4-triazol-3-yl)-1,10-biphenyl (21). This
was prepared according to a modified method.30 A stirred solution
of 4-methyl-20-isothiocarboximino-1,10-biphenyl, methiodide 20
(2.65 g, 6.8 mmol) dissolved 25 mL of dry dimethylformamide un-
der nitrogen atmosphere was treated with formic hydrazide
(0.81 g, 14 mmol). The reaction was stirred at room temperature
for 16 h, and then heated at 90 °C for 4 h. The cooled reaction mix-
ture was poured into water and extracted with ether. The com-
bined extracts were washed with water (4ꢃ 10 mL), dried over
magnesium sulfate, filtered, and evaporated under vacuum to give
the title compound 21 (0.90 g, 56.3%). Mp 157.1–158.1 °C; 1H NMR
(600 MHz, CDCl3): d 2.41 (s, 3H), 6.48 (br s, 2H), 7.3 (m, 7H), 7.9
(dd, J = 7.86 Hz, 2H); 13C NMR (150 MHz, CDCl3): d 21.32, 118.54,
127.82, 128.11, 129.01, 129.55, 130.61, 135.22, 135.95, 139.03,
151.23, 159.82; MS (ESI) m/z 236.3 (MH+).
4.2.3.5. 40-{[2-n-Propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(5-chloro-1-(triphenylmethyl)-
imidazole-2-yl)biphenyl (18). The title compound 18 was pre-
pared from compound 17 using the procedure described in the
preparation of compound 10. Compound 18 (41.2%, yield). Mp
209.5–212.1 °C; 1H NMR (600 MHz, CDCl3):
d
1.06–1.09 (t,
J = 7.35 Hz, 3H), 1.89–1.95 (m, 2H), 2.79 (s, 3H), 2.96–2.98 (t,
J = 7.83 Hz, 2H), 3.74 (s, 3H), 5.46 (s, 2H), 6.30 (s,1H), 6.66–6.67
(d, J = 7.62 Hz, 6H), 6.93–6.96 (t, J = 7.83 Hz, 6H), 6.95–6.98 (m,
2H), 7.03–7.10 (m, 8H), 7.27–7.31 (m, 3H), 7.33–7.36 (m, 1H),
7.46 (s, 1H), 7.56 (s, 1H), 7.78–7.80 (m, 1H); 13C NMR (150 MHz,
CDCl3): d 12.7, 19.9, 23.5, 30.6, 47.2, 58.3, 110.9, 115.3, 122.3,
123.5, 124.4, 127.3, 128.4, 129.5, 133.4, 134.0, 135.5, 135.6,
138.4, 138.5, 141.8, 153.3, 153.5, 154.5; MS (ESI) m/z 813.5
(MH+). Anal. Calcd for C54H45ClN6: C, 79.73; H, 5.58; Cl, 4.36; N,
10.33. Found: C, 79.60; H, 5.63; Cl, 4.33; N, 10.36.
4.2.4.4. 4-Methyl-20-(1-triphenylmethyl-1,2,4-triazol-3-yl)-1,10-
biphenyl (22). The title compound 22 was prepared from com-
pound 21 using the procedure described in the preparation of com-
pound 8. Compound 22 (87.2%, yield). Mp 133.1–134.7 °C; 1H NMR
(600 MHz, CDCl3): d 2.42 (s, 3H), 2.94 (s, 3H), 7.27 (s, 4H), 7.51 (m,
2H), 7.65 (t, 2H); 13C NMR (150 MHz, CDCl3): d 21.37, 118.5, 126.2,
127.8, 128.0, 129.2, 129.5, 135.1, 135.4, 139.0, 143.6, 160.1; MS
(ESI) m/z 478.5 (MH+). Anal. Calcd for C34H27N3: C, 85.50; H,
5.70; N, 8.80. Found: C, 85.66; H, 5.49; N, 8.40.
4.2.3.6. 40-[[4-Methyl-6-(1-methyl-benzoimidazol-2-yl)-2-pro-
pyl-benzoimidazol]-1-yl]methyl-2-(5-chloroimidazole-2-yl)-
biphenyl (2). The title compound 2 was prepared from com-
pound 18 using the procedure described in the preparation of
compound 1. Compound 2 (84%, yield). Mp 147.2–148.3 °C; 1H
NMR (600 MHz, CDCl3): d 1.08–1.10 (t, J = 7.35 Hz, 3H), 1.82–
1.93 (m, 2H), 2.76 (s, 3H), 2.96–2.98 (t, J = 7.86 Hz, 2H), 3.86 (s,
3H), 5.39 (s, 2H), 6.48 (s, 1H), 7.06–7.08 (d, J = 7.98 Hz, 2H),
7.21–7.22 (d, J = 8.04 Hz, 2H), 7.28–7.32 (m, 6H), 7.41–7.42 (m,
4.2.4.5. 4-Bromomethyl-20-(1-triphenylmethyl-1,2,4-triazol-3-
yl)-1,10-biphenyl (23). The title compound 23 was prepared from
compound 22 using the procedure described in the preparation of
9. The crude product is routinely used without further purification.

X.-Z. Guo et al. / Bioorg. Med. Chem. 16 (2008) 10301–10310
10309
4.2.4.6. 40-{[2-n-Propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(1-triphenylmethyl-1,2,4-tria-
zol-3-yl)biphenyl (24). The title compound 24 was prepared
from compound 23, using the procedure described in the prepara-
tion of compound 10. Compound 24 (45%, yield). Mp 250.8–
251.7 °C; 1H NMR (600 MHz, CDCl3): d 2.40 (s, 3H), 7.15 (d,
J = 7.89 Hz, 2H), 7.21 (d, J = 7.89 Hz, 2H), 7.34 (m, 1H), 7.44 (m,
2H), 8.05 (s, 1H), 8.15 (dd, 1H); 13C NMR (150 MHz, CDCl3): d
14.0, 16.9, 21.8, 30.0, 31.7, 47.0, 78.0, 109.0, 109.5, 119.6, 122.3,
122.4, 123.8, 125.5, 127.5, 127.8, 128.1, 129.0, 129.4, 130.0,
130.2, 130.6, 133.9, 135.1, 136.7, 140.8, 142.0, 143.0, 143.2,
145.9, 154.7, 156.4, 162.3; ESI-HRMS: m/z calcd for [C53H46N7]+:
780.9795; found: 780.3809.
was dissected from hind legs, and separate inferior branch arteria
saphena from femoral artery. The artery was cannulated and con-
nected to a pressure transducer (TP-400T, Japan Opto-Electronics)
coupled to polygraph (PEG-1000, Japan Opto-Electronics) and a
carrier amplifier (PP-101H, Japan Opto-Electronics) for measure-
ment of blood pressure and heart rate and all data were collected
using
a polygraph data processing system (PEG-1000, Japan
Opto-Electronics). The normal blood pressure and heart rate were
recorded after stable, and then the test compound (2.13 mg/kg)
was orally administered. Blood pressure and heart rate were mon-
itored after 1 h administration of the test compounds so that to
study the effect of test compounds on blood pressure and heart
rate. Waveforms of blood pressure and heart rate for each dog were
recorded after 1 min injection of AngII (0.45 lg/kg). Eight max val-
4.2.4.7. 40-{[2-n-Propyl-4-methyl-6-(1-methylbenzoimidazol-2-
yl)benzoimidazol-1-yl]methyl}-2-(1H-1,2,4-triazol-3-yl)biphenyl
(3). The title compound 3 was prepared from compound 24, using
the procedure described in the preparation of compound 1. Com-
pound 3 (87%, yield). Mp 197.4–198.7 °C; 1H NMR (600 MHz,
CDCl3): d 1.08–1.10 (t, J = 7.35 Hz, 3H), 1.88–1.94 (m, 2H), 2.76 (s,
3H), 3.01–3.03 (t, J = 7.32 Hz, 2H), 3.79 (s, 3H), 5.43 (s, 2H), 6.92–
6.94 (d, J = 7.38 Hz, 2H), 7.12–7.13 (d, J = 8.04 Hz, 2H), 7.20 (s,
1H), 7.25–7.28 (m, 2H), 7.30–7.33 (t, J = 6.60 Hz, 1H), 7.38–7.47
(m, 4H), 7.62–7.63 (d, J = 8.04 Hz, 1H), 7.94–7.98 (m, 1H), 8.03 (s,
1H) 15.86 (s, 1H); 13C NMR (150 MHz, CDCl3): d 14.1, 17.0, 21.8,
29.9, 31.6, 47.1, 108.9, 109.4, 119.6, 122.3, 122.5, 123.8, 125.5,
128.1, 129.0, 129.4, 129.9, 130.3, 133.8, 135.1, 136.7, 140.8,
143.0, 143.2, 145.8, 154.7, 156.4, 162.3; ESI-HRMS: m/z calcd for
[C34H32N7]+: 538.6651; found: 538.2714.
ues were fetched at each of time point and the average value was
obtained to avoid data acquisition with experiment error. The
blood pressure lowering effects of the test compounds was express
as the change rate after 1 h administration of the test compounds
and injection of AngII as interclass statistics. The difference be-
tween the maximum blood pressure increase before and after drug
was reported as the percent (%) inhibition of the AngII pressor
effect.
Acknowledgments
We acknowledge the financial support from the Knowledge
Innovation Program of the Chinese Academy of Sciences, and Diao
Pharmaceutical Company. We also are grateful to Guang-xin Dong
for his assistance with the biological testing.
4.3. Biological activities
References and notes
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