Design, synthesis, and cytotoxic activities of new 2,4,5-triarylimidazoles

Article abstract of DOI:10.1007/s00044-012-0391-5

A new group of 2,4,5-triarylimidazoles containing N,N-dimethylaminoethoxy or piperidinyl ethoxy group at the para position of the C-5 phenyl ring were synthesized and their cytotoxic activities were evaluated on three different breast cancer cell lines using MTT assay. The compounds contain various substituents at the para position of C-2 phenyl ring. Among the synthesized compounds, 4-(5-(4-(2-piperidin-1-yl)ethoxy)phenyl)-4-phenyl-1H-imidazol-2-yl) phenol (11e) and 1-2-(4-(2,4-diphenyl-1H-imidazol-5-yl)phenoxy)ethyl) piperidine (11h) with IC₅₀s of less than 0.1 μM on all three cell lines were the most potent cytotoxic compounds.

Full text of DOI:10.1007/s00044-012-0391-5

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2013) 22:3897–3904
DOI 10.1007/s00044-012-0391-5
ORIGINAL RESEARCH
Design, synthesis, and cytotoxic activities
of new 2,4,5-triarylimidazoles
•
A. Zarghi S. Arfaei F. H. Shirazi
•
Received: 8 July 2012 / Accepted: 4 December 2012 / Published online: 15 December 2012
Ó Springer Science+Business Media New York 2012
Abstract A new group of 2,4,5-triarylimidazoles con-
taining N,N-dimethylaminoethoxy or piperidinyl ethoxy
group at the para position of the C-5 phenyl ring were syn-
thesized and their cytotoxic activities were evaluated on
three different breast cancer cell lines using MTT assay. The
compounds contain various substituents at the para position
of C-2 phenyl ring. Among the synthesized compounds,
4-(5-(4-(2-piperidin-1-yl)ethoxy)phenyl)-4-phenyl-1H-imi-
dazol-2-yl)phenol (11e) and 1-2-(4-(2,4-diphenyl-1H-imi-
dazol-5-yl)phenoxy)ethyl) piperidine (11h) with IC50s of
less than 0.1 lM on all three cell lines were the most potent
cytotoxic compounds.
to possess antibiotic (Brogden et al., 1978), anti-fungal
(Di Santo et al., 2005), anti-inflammatory (Mano et al.,
2003), COX-2 inhibitors (Zarghi et al., 2012), and cyto-
toxic activities (Narasimhan et al., 2011). Imidazole
compounds have been an interesting source for research-
ers for more than a century and many of them are being
used as chemotherapy compounds today. A wide variety
of imidazole containing compounds having cytotoxic
activities on different cancer cell lines with different
mechanisms of action have been developed over years,
such as inhibitors of B-Raf kinase 1,2 (Takle et al., 2006),
combretastatin analogs 3,4 (Wang et al., 2002), and
modulators of P-glycoprotein (P-gp)-mediated multidrug
resistance (MDR) 5,6 (Newman et al., 2000; Robert and
Jarry, 2003) shown in Fig. 1. Tamoxifen 7 was developed
more than 30 years ago for the treatment of advanced
breast cancer (Osborne, 1998). Tamoxifen, like other
SERMs, binds to estrogen receptor (ER) and, in breast
cancer cells, antagonizes the effect of estrogen on a
variety of growth-regulatory genes (Dhingra, 1999). The
predominant effect of tamoxifen and many other SERMs
is cytostatic, by inducing a G1 cell cycle block, thereby
slowing cell proliferation. Tamoxifen may also induce
apoptosis, although this process has not always been easy
to demonstrate in tumors (Ellis et al., 1997). Based upon
the anti-cancer properties of imidazole compounds in
Fig. 1 and anti-breast cancer effects of tamoxifen, new
2,4,5-triaryl-1H-imidazoles were designed, synthesized,
and their cytotoxic activities were evaluated on three
breast cancer cell lines. For designing the new imidazoles,
the vicinal diaryl moiety and the basic side chain
(N,N-dialkylamino ethoxyphenyl) was derived from the
structure of tamoxifen, while the total 2,4,5-triarylimi-
dazole resembles the other cytotoxic imidazole com-
pounds shown in Fig. 1.
Keywords Synthesis Á 2,4,5-Triarylimidazoles Á
Cytotoxic activity Á MTT Á Docking study
Introduction
Imidazole scaffold exists in many significant biomole-
cules including biotin, histamine, and amino acids such as
histidine. Many compounds possessing significant bio-
chemical and pharmacological roles contain imidazole
nucleus. Members of this class of heterocycles are known
A. Zarghi (&) Á S. Arfaei
Department of Medicinal Chemistry,
School of Pharmacy, Shahid Beheshti University of Medical
Sciences, P.O. Box 14155-6153, Tehran, Iran
e-mail: azarghi@yahoo.com
F. H. Shirazi
Department of Toxicology, School of Pharmacy,
Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Med Chem Res (2013) 22:3897–3904
Cl
N
HO
HO
N
N
O
N
H
N
H
NMe2
1
N
N
2
OMe
OMe
MeO
MeO
MeO
N
N
MeO
N
N
H
R
4
MeO
N
3
R= F, NH2
H
N
Me2N
N
N
N
H
N
H
COOH
OEt
6
N
H
5
Me2N
N
X
N
H
R
N
8
O
N
O
7
R
Fig. 1 Structures of imidazole compounds, tamoxifen (7) and our designed molecules (8)
Results and discussions
et al., 2012). Primarily 1-(4-hyroxyphenyl)-2-phenyletha-
none 8 was synthesized using Friedel–Crafts reaction
between phenol and phenylacetic acid in the presence of
Lewis acid BF3ÁEt2O (Wahala and Hase, 1991). Compound 8
was then oxidized to diketone 9 using selenium dioxide
(Caturla et al., 2004). Diketone 9 undergone a nucleophilic
substitution reaction with appropriate reagents (N-(2-chlo-
roethyl)-N,N-dimethylammonium chloride or (N-(2-chloro
ethyl)-piperidinium chloride) to add the basic side chain and
Chemistry
As shown in Scheme 1 the target 2,4,5-triaryl-1H-imidazole
derivatives 11a–h were synthesized via a one-pot microwave
reaction between 1,2-diketone 10 and the appropriate aro-
matic aldehyde in the presence of ammonium acetate under
microwave irradiation (Wolkenberg et al., 2004; Zarghi
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Med Chem Res (2013) 22:3897–3904
3899
O
OH
OH
a
b
+
O
HO
8
O
O
O
O
R
c
d
N
HO
R
O
9
10 (a,b)
H
N
X
N
R
R
X: H, F, OCH3, OH
N
N
N
=
R
N
O
11 (a-h)
R
Scheme 1 Reagents and conditions: a BF3ÁEt2O, 80 °C; b SeO2, dioxane/H2O, reflux; c N-(2-chloroethyl)-N,N-dimethylammonium chloride or
N-(2-chloroethyl)-piperidinium chloride, K2CO3, acetonitrile, reflux; d Ar-CHO, NH4OAc, AcOH, MW, 180 W, 10 min
was converted to diketone 10 (a, b) (Um et al., 2003). 1,2-
Diketone 10 was used to synthesize the final 2,4,5-triaryl-
1H-imidazoles 11a–h via the multi-component microwave
reaction. The purity of all products was determined by thin
layer chromatography using several solvent systems of dif-
ferent polarity. All compounds were pure and stable. The
to these results, all compounds 11a–h were cytotoxic
against three different breast cancer cell lines. In addition,
our results indicated that the synthesized compounds
11a–h were more cytotoxic against T47D cells which
contain high amounts of estrogen receptors in comparison
with those of MCF7 and MDA-MB-231. This may be due
to the ability of synthesized compounds to blockade
estrogen receptors in breast cancer cell lines. However, our
results showed that some compounds (11d, 11e, and 11h)
had similar cytotoxic activities on MDA-MB-231 cell line
as well which indicated that other anti-cancer mechanisms
may be involved in addition to blockade estrogen receptors
in breast cancer cell lines. Moreover, our results indicated
that among the synthesized compounds, 11e and 11h
containing piperidino basic side chain with IC50s of less
than 0.1 lM on all three cell lines had the highest cytotoxic
effects and were the most potent compounds in this group.
1
compounds were characterized by HNMR, MS, IR, and
CHN analysis. The physical data of final synthesized deriv-
atives were summarized in Table 1.
Cytotoxicity
The cytotoxicity of compounds 11a–h was determined on
breast cancer cell lines using MTT assay (Mosmann, 1983).
The MTT assay of the compounds was performed on three
different breast cancer cell lines: MCF-7 and T47D (con-
taining medium to high levels of estrogen receptors) and
MDA-MB-231 (without estrogen receptors) (Siciliano
et al., 1979; Dickstein et al., 1993; Keydar et al., 1979) to
indicate that the anti-proliferative activities of designed
compounds are mediated through hormone-dependent or
hormone-independent mechanisms. The results of MTT
assay of these compounds are shown in Table 2. According
Docking study
Regarding the resemblance between the structures of the
designed 2,4,5-triaryl-1H-imidazoles 11a–h and the struc-
ture of tamoxifen and obtained MTT assay results, it could be
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Med Chem Res (2013) 22:3897–3904
Table 1 Physicochemical properties of compounds 2,4,5-triarylimidazoles 11a–h
H
N
X
N
R
N
O
R
R
N
Molecular
formula
Molecular
weight
Compound
X
MP °C Yield%
R
CH3
147–
36
N
N
N
N
11a
OH
C25H25N3O2
C25H24N3OF
C26H27N3O2
C25H25N3O
399.5
401.5
413.5
383.5
149
CH3
CH3
172–
30
11b
11c
11d
F
OMe
H
173
CH3
CH3
159–
46
160
CH3
CH3
150–
35
151
CH3
N
N
N
N
225–
20
11e
11f
OH
F
C28H29N3O2
C28H28N3OF
C29H31N3O2
C28H29N3O
439.5
441.5
453.6
423.5
227
188–
26
190
118–
30
120
11g
11h
OMe
H
117–
34
118
assumed that one of the mechanisms of cytotoxic activities of
compounds 11a–h on breast cancer cell lines might be
through acting on estrogen receptors. Therefore, the orien-
tation of 4-(5-(4-(2-(dimethylamino)ethoxy)phenyl)-4-phe-
nyl-1H-imidazol-2-yl)phenol 11a in the estrogen receptor a
(ERa) active site was examined by a docking experiment
(Fig. 2). This molecular modeling study shows that com-
pound 11a was well bound in the active site of ERaso that the
N atom of the tertiary amino group of the basic side chain
(dimethylaminophenoxy), which can be protonized in
physiologic pH, is in the vicinity of the oxygen of carbox-
ylate group of Asp351 (distance = 4.7 A) and is capable of
˚
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Med Chem Res (2013) 22:3897–3904
3901
General
Table 2 In vitro cytotoxicity data of compounds 11a–h using MTT
assay
Melting points (mp) were determined using a Thomas
Hoover melting point apparatus (Philadelphia, USA). Syn-
thos 3000 microwave oven (Anton Paar, Austria) was used to
synthesize the final compounds. Infrared spectra were
acquired on a Perkin Elmer 1420 ratio recording spectrom-
eter. A Bruker FT-500 MHz instrument (Brucker Biosci-
Compound
MDA-MB-231
IC50 (lM)
T47D IC50
(lM)
MCF-7 IC50
(lM)
11a
82
76
6
4
2
4
63
61
3
3
2
3
70
82
5
2
4
4
11b
11c
53
28
42
11d
58
50
53
1
ences, Germany) was used to acquire HNMR spectra and
11e
\0.1
[100
71
\0.1
61
\0.1
78
chloroform-D was used as solvent. Coupling constant
(J) values are estimated in hertz (Hz) and spin multiples are
given as s (singlet), d (double), t (triplet), q (quartet), m
(multiplet), and br (broad). The mass spectral measurements
were performed on an 6410 Agilent LCMS triple quadrupole
mass spectrometer (LCMS) with an electrospray ionization
(ESI) interface. Elemental analyses were carried out with a
Perkin Elmer Model 240-C apparatus (Perkin Elmer, Nor-
walk, CT, USA). The results of the elemental analyses (C, H,
N) were within 0.4 % of the calculated amounts.
11f
4
2
4
4
11g
2
54
65
11h
\0.1
55.5 2.7
\0.1
12.1 0.9
\0.1
25.1 1.5
Tamoxifen
Experimental values represent the average for two experiments per-
formed in triplicate along with the standard deviation (SD) between
the assay values
binding to this amino acid. The OH group at the para position
of C-2 phenyl ring is in the vicinity of ASP394 and Glu353 so
˚
that the H atom of OH group is in a 4.3 A distance from the O
atom of carboxylate group in Glu353 and the O atom of the
Preparation of 1-(4-hydroxyphenyl)-2-phenylethanone 8
˚
OH group is in a 3.0 A distance from H atom of the NH group
in Arg394 (Barrett et al., 2008). These data together with
biological results may explain that one of the mechanisms of
cytotoxic activities of compounds 11a–h on breast cancer
cell lines might be through acting on estrogen receptors.
Equimolar amounts of phenol and phenyl acetic acid were
added to 40 ml of BF3ÁEt2O and stirred under Argon
atmosphere in 0 °C for 15 min. The reaction temperature
was then allowed to gradually reach the room temperature
and subsequently the reaction mixture was refluxed in
75 °C for 20 h. After cooling, the reaction mixture was
poured onto crushed ice, 20 ml of ethyl acetate was added
and the organic phase was separated and washed primarily
with water and afterward with saturated NaHCO3 solution,
dried with sodium sulfate and evaporated under vacuum.
The oily residue was dissolved in DCM and precipitates
formed by adding hexane drop wise. The precipitate was
filtered and recrystallized in DCM to obtain white powder.
Yield: 21 %; Mp: 148–150 °C; IR (KBr): t (cm-1) 3,340
(OH), 1,670 (C=O); MS m/z (%): 212.1 (M?, 10), 181.0
(15), 165.0 (10), 152.0 (10), 120.9 (10), 93.1 (60).
Experimental
Materials
All reagents were purchased from the Aldrich (USA) or
Merck (Germany) Chemical Company and were used
without further purifications.
Preparation of 1-(4-hydroxyphenyl)-2-phenylethan-1,2-
dione 9
4 g (0.0188 mmol) of compound 8 was dissolved in 15 ml
dioxane and added to a solution of 12 g SeO2 in 50 ml
dioxane and 10 ml water. The reaction mixture was refluxed
for 24 h. After cooling, selenium was filtered off and the
filtrate was poured onto crushed ice and extracted with ethyl
acetate. The organic phase was washed with water and dried
with sodium sulfate and evaporated under vacuum. The oily
residue was dissolved in DCM and the precipitates were
formed by adding hexane drop wise. The precipitate was
filtered and recrystallized in DCM to obtain orange powder.
Yield: 64 %; Mp: 127–129 °C; IR (KBr): t (cm-1) 3,385
Fig. 2 Docking 11a (in orange) in the active site of human ERa.
Hydrogen atoms have been removed to improve clarity (Color figure
online)
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Med Chem Res (2013) 22:3897–3904
(OH), 1,670, 1,645 (C=O); MS m/z (%): 226.1 (M?, 10),
product precipitated immediately. The precipitate was fil-
tered and washed with water and purified using column
chromatography (Yields: 20–46 %).
121.0 (100), 105.1 (75), 93.1 (70), 77.0 (85).
Preparation of 1-(4-(2-(piperidin-1-yl or dimethlamino)
ethoxy)phenyl)-2-phenylethan-1,2-dione (10a, b)
4-(5-(4-(2-(Dimethylamino)ethoxy)phenyl)-4-phenyl-1H-
imidazol-2-yl)phenol 11a
1 g (4.42) mmol of diketone 9 was dissolved in 40 ml
acetonitrile and 5.8 g K2CO3 was added while stirring.
Four equivalents of N-(2-chloroethyl)piperidinium chloride
or N-(2-chloroethyl)-N,N-dimethylammonium chloride was
added subsequently and the reaction mixture was refluxed
for 24 h. The inorganic material was filtered off and the
filtrate was evaporated under vacuum, dissolved in DCM
and washed with brine. The organic phase was dried with
sodium sulfate and evaporated. The oily residue was
purified using column chromatography with a mobile phase
of CHCl3/n-hexane (9:1 v/v), to obtain a pure yellow vis-
cous oil.
IR (KBr): t (cm-1) 3,500–2,500 (OH), 3,058 (NH); LC–MS
(ESI)m/z: 400.8 (M ? 1)(100);1HNMR(CDCl3, 500 MHz):
d 2.27 (s, 6H, N(CH3)2), 2.66–2.68 (t, 2H, CH2N,
J = 5.7 Hz), 3.99–4.01 (t, 2H, OCH2, J = 5.7 Hz),
6.77–6.79(d,4H, 2-phenylH3 andH5 and5-phenylH3 andH5,
J = 8.7 Hz), 7.12–7.15 (m, 1H, 4-phenyl H4), 7.19–7.22 (m,
2H, 4-phenyl H3 and H5), 7.37 (d, 2H, 4-phenyl H2 and H6,
J = 8.6 Hz), 7.47 (d, 2H, 5-phenyl H2 and H6, J = 7.5 Hz),
7.79 (d, 2H, 2-phenyl H2 and H6, J = 8.6 Hz), 9.32 (s, 1H,
NH); Anal. Calcd. for. C25H25N3O2: C, 75.16; H, 6.31; N,
10.52. Found: C, 75.32; H, 6.65; N, 10.39.
1-(4-(2-(Piperidin-1-yl)ethoxy)phenyl)-2-phenylethan-1,
2-(4-(2-(4-Fluorophenyl)-4-phenyl-1H-imidazol-5-
2-dione 10a
yl)phenoxy)-N,N-dimethylethanamine 11b
Yield: 30 %; IR (CCl4): t (cm-1) 1,715, 1,685 (C=O);
LC–MS (ESI) m/z : 338.8 (M ? 1) (100); 1HNMR (CDCl3,
500 MHz): d 1.48–1.52 (m, 2H, piperidine CH2), 1.65–1.69
(m, 4H, piperidine CH2), 2.57–2.60 (m, 4H, piperidine CH2),
2.86–2.88 (t, 2H, CH2N, J = 5.9 Hz), 4.23–4.25 (t, 2H,
OCH2, J = 5.9 Hz), 6.99 (d, 2H, 1-phenyl H3 and H5,
J = 9.0 Hz), 7.53–7.56 (m, 2H, 2-phenyl H3 and H5),
7.67–7.70 (t, 1H, 2-phenyl H4, J = 7.4 Hz), 7.96 (d, 2H,
1-phenyl H2 and H6, J = 9.0 Hz), 8.00 (d, 2H, 2-phenyl H2
and H6, J = 7.2 Hz).
IR (KBr) : t (cm-1) 3,050 (NH); LC–MS (ESI) m/z : 402.8
(M ? 1) (100); 1HNMR (CDCl3, 500 MHz): d 2.39 (s, 6H,
N(CH3)2), 2.79–2.81 (t, 2H, CH2N, J = 5.4 Hz), 4.12–4.14
(t, 2H, OCH2, J = 5.4 Hz), 6.90 (d, 2H, 5-phenyl H3 and H5,
J = 8.0 Hz), 7.12–7.15 (t, 2H, 2-phenyl H3 and H5), 7.29 (m,
1H, 4-phenyl H4), 7.33–7.35 (m, 2H, 5-phneyl H2 and H6),
7.45 (m, 2H, 4-phenyl H3 and H5), 7.58 (m, 2H, 4-phenyl H2
and H6), 7.90–7.92 (t, 2H, 2-phenyl H2 and H6), 9.44 (s, 1H,
NH). Anal. Calcd. for. C25H24N3OF: C, 74.79; H, 6.03; N,
10.47. Found: C, 74.99; H, 6.25; N, 10.31.
1-(4-(2-(Dimethlamino)ethoxy)phenyl)-2-phenylethan-1,
2-(4-(2-(4-Methoxyphenyl)-4-phenyl-1H-imidazol-5-
2-dione 10b
yl)phenoxy)-N,N-dimethylethanamine 11c
Yield: 32 %; IR (CCl4): t (cm-1) 1,720, 1,680 (C=O);
LC–MS (ESI) m/z : 298.9 (M ? 1) (100); 1HNMR (CDCl3,
500 MHz): d 2.39 (s, 6H, N(CH3)2), 2.80–2.82 (t, 2H, CH2N,
J = 5.6 Hz), 4.18–4.20 (t, 2H, OCH2, J = 5.6 Hz), 7.03 (d,
2H, 1-phenyl H3 and H5, J = 8.6 Hz), 7.53–7.56 (m, 2H,
2-phenyl H3 and H5), 7.67–7.70 (t, 1H, 2-phenyl H4,
J = 7.3 Hz), 7.97 (d, 2H, 1-phenyl H2 and H6, J = 8.6 Hz),
8.01 (d, 2H, 2-phenyl H2 and H6, J = 8.2 Hz).
IR (KBr) : t (cm-1) 3,070 (NH); LC–MS (ESI) m/z : 414.8
(M ? 1) (100); 1HNMR (CDCl3, 500 MHz): d 2.37 (s, 6H,
N(CH3)2), 2.77–2.80 (t, 2H, CH2N, J = 5.7 Hz), 3.87 (s, 3H,
OCH3), 4.10–4.12 (t, 2H, OCH2, J = 5.7 Hz), 6.88 (d, 2H,
5-phenyl H3 and H5, J = 8.7 Hz), 6.95 (d, 2H, 2-phenyl H3
and H5, J = 8.7 Hz), 7.25–7.28 (m, 1H, 4-phenyl H4),
7.32–7.34 (m, 3H, 5-phenyl H2 and H6, and NH), 7.44 (d, 2H,
4-phenyl H3 and H5, J = 7.6 Hz), 7.56 (d, 2H, 4-phenyl H2
and H6, J = 7.6 Hz), 7.86 (d, 2H, 2-phenyl H2 and H6,
J = 8.7 Hz); Anal. Calcd. for. C26H27N3O2: C, 75.52; H,
6.58; N, 10.16. Found: C, 75.66; H, 6.35; N, 10.22.
General procedure for preparation of 2,4,5-triaryl-1H-
imidazoles 11a–h
Equivalent amounts of diketone 10 (a or b) and appropriate
aromatic aldehyde along with 2 g ammonium acetate in 6 ml
glacial acetic acid were placed in microwave reactor for
10 min, while the power was set at 180 W. After cooling, the
solution was neutralized with aqueous ammonia in which the
2-(4-(2,4-Diphenyl-1H-imidazol-5-yl)phenoxy)-
N,N-dimethylethanamine 11d
IR (KBr) : t (cm-1) 3,065 (NH); LC–MS (ESI) m/z : 384.9
(M ? 1) (100); 1HNMR (CDCl3, 500 MHz): d 2.48 (s, 6H,
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Med Chem Res (2013) 22:3897–3904
3903
1-2-(4-(2,4-Diphenyl-1H-imidazol-5-yl)phenoxy)ethyl)
N(CH3)2), 2.89–2.91 (t, 2H, CH2N, J = 5.2 Hz), 4.18–4.20
(t, 2H, OCH2, J = 5.2 Hz), 6.91 (d, 2H, 5-phenyl H3 and
H5, J = 8.5 Hz), 7.35–7.60 (m, 10H, 5-phenyl H2 and H6,
4-phenyl and 2-phenyl H3–H5), 7.97 (d, 2H, 2-phenyl H2
and H6, J = 7.68 Hz), 9.38 (s, 1H, NH); Anal. Calcd. for.
C25H25N3O: C, 78.30; H, 6.57; N, 10.96. Found: C, 78.61;
H, 6.85; N, 11.12.
piperidine 11h
IR (KBr): t (cm-1) 3,078 (NH); LC–MS (ESI) m/z : 424.7
1
(M ? 1) (100); HNMR (CDCl3, 500 MHz): d 1.55–1.58
(m, 2H, piperidine CH2), 1.81–1.84 (m, 4H, piperidine
CH2), 2.78–2.83 (m, 4H, piperidine CH2), 3.02–3.04 (m,
2H, CH2N), 4.30–4.32 (m, 2H, OCH2), 6.88 (d, 2H,
5-phenyl H3 and H5, J = 7.5 Hz), 7.37–7.59 (m, 10H,
5-phenyl H2 and H6, 4-phenyl and 2-phenyl H3–H5), 8.00
(d, 2H, 2-phenyl H2 and H6, J = 7.6 Hz), 8.88 (s, 1H, NH);
Anal. Calcd. for. C28H29N3O: C, 79.40; H, 6.90; N, 9.92.
Found: C, 79.68; H, 6.77; N, 10.11.
4-(5-(4-(2-Piperidin-1-yl)ethoxy)phenyl)-4-phenyl-1H-
imidazol-2-yl)phenol 11e
IR (KBr): t (cm-1) 3,500–2,500 (OH), 3,056 (NH); LC–
MS (ESI) m/z : 440.2 (M ? 1) (100); HNMR (CDCl3,
1
500 MHz):
d 1.43–1.45 (m, 2H, piperidine CH2),
Cytotoxicity studies
1.60–1.64 (m, 4H, piperidine CH2), 2.50–2.54 (m, 4H,
piperidine CH2), 2.78–2.81 (t, 2H, CH2N, J = 5.9 Hz),
4.10–4.12 (t, 2H, OCH2, J = 5.9 Hz), 6.80 (d, 2H,
2-phenyl H3 and H5, J = 8.8 Hz), 6.83 (d, 2H, 5-phenyl H3
and H5, J = 8.7 Hz), 7.19–7.21 (m, 1H, 4-phenyl H4),
7.26–7.30 (m, 3H, 4-phenyl H2 and H6, NH), 7.42 (d, 2H,
4-phenyl H3 and H5, J = 8.5 Hz), 7.53 (d, 2H, 4-phenyl H2
and H6, J = 7.4 Hz), 7.81 (d, 2H, 5-phenyl H2 and H6,
J = 8.7 Hz); Anal. Calcd. for. C28H29N3O2: C, 76.51; H,
6.65; N, 9.56. Found: C, 76.36; H, 6.45; N, 9.75.
The anti-proliferative activities of the compounds were
determined on three breast cancer cell lines using MTT
assay. 1 9 104 cells/well were seeded in 198 ll RPMI
(phenol red free) medium, supplemented with 10 % FBS in
each well of 96-well micro culture plates and incubated for
24 h at 37 °C in a CO2 incubator. 2 ll of the compounds,
diluted to the desired concentrations in DMSO, were added
to the wells with respective vehicle control. After 72 h of
incubation, media were removed and to each well 20 ll
MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazo-
lium bromide) (5 mg/ml) was added and the plates were
further incubated for 4.5 h. Then, the supernatant from
each well was carefully removed, formazan crystals were
dissolved in 200 ll of DMSO and absorbance at 540 nm
wavelength were recorded.
1-(2-(4-(2-(4-Fluorophenyl)-4-phenyl-1H-imidazol-5-
yl)phenoxy)ethyl)piperidine 11f
IR (KBr): t (cm-1) 3,050 (NH); LC–MS (ESI) m/z: 442.8
(M ? 1) (100); 1HNMR (CDCl3, 500 MHz): d 1.49–1.53 (m,
2H, piperidine CH2), 1.65–1.69 (m, 4H, piperidine CH2),
2.57–2.61 (m, 4H, piperidine CH2), 2.85–2.87 (t, 2H, CH2N,
J = 5.5 Hz), 4.15–4.18 (t, 2H, OCH2, J = 5.5 Hz),
6.90–6.94 (m, 2H, 5-phenyl H3 and H5), 7.15–7.18 (t, 2H,
2-phenylH3 andH5, J = 7.0 Hz), 7.34–7.69(m, 7H, 5-phenyl
H2 and H6 and 4-phenyl), 7.91–7.94 (dd, 2H, 2-phenyl H2 and
H6), 9.46 (s, 1H, NH); Anal. Calcd. for. C28H28N3OF: C,
76.16; H, 6.39; N, 9.52. Found: C, 76.23; H, 6.54; N, 9.69.
Molecular modeling (docking) studies
Docking studies were performed using Autodock Vina
software (Trott and Olson, 2010). The coordinates of the
X-ray crystal structure of the selective estrogen receptor
modulator lasofoxifene bound to the human estrogen
receptor a was obtained from the RCSB Protein Data Bank
(2OUZ) and hydrogens were added, Kollman charge was
calculated and non-polar hydrogens were deleted. The ligand
molecule was constructed using the Hyperchem 8.0.3 and
was energy minimized using AMBER MM force field,
Polak–Ribier algorithm for 1,000 iterations reaching a con-
1-(2-(4-(2-(4-Methoxyphenyl)-4-phenyl-1H-imidazol-5-
yl)phenoxy)ethyl)piperidine 11g
IR (KBr): t (cm-1) 3,068 (NH); LC–MS (ESI) m/z: 454.7
1
(M ? 1) (100); HNMR (CDCl3, 500 MHz): d 1.48–1.51
˚
˚
vergence of 0.01 kcal/mol A. A grid box of 24–24–24 A
with the central X–Y–Z coordinates of X: 30.6130 Y: -1.2140
Z: 27.6360 was built for calculation of the energy map. In the
end of docking process, conformations having optimal
docking energy were visualized using Viewer Lite 5.0 soft-
(m, 2H, piperidine CH2), 1.65–1.68 (m, 4H, piperidine
CH2), 2.55–2.58 (m, 4H, piperidine CH2), 2.83–2.85 (t, 2H,
CH2N, J = 5.5 Hz), 3.90 (s, 3H, OCH3), 4.16–4.18 (t, 2H,
OCH2, J = 5.5 Hz), 6.79–6.80 (m, 2H, 5-phenyl H3 and
H5), 7.00 (d, 2H, 2-phenyl H3 and H5, J = 7.9 Hz),
7.35–7.69 (m, 6H, 5-phenyl H2 and H6, 4-phenyl), 7.87 (d,
2H, 2-phenyl H2 and H6, J = 8.0 Hz), 9.31 (s, 1H, NH);
Anal. Calcd. for. C29H31N3O2: C, 76.79; H, 6.89; N, 9.26.
Found: C, 76.99; H, 7.02; N, 8.98.
˚
ware, residues with atoms[7.5 A from the docking box were
removed for efficiency and the distances between atoms of
ligand and amino acids in the active site were calculated. For
docking validation, lasofoxifene was docked in the active
123

3904
Med Chem Res (2013) 22:3897–3904
Mano T, Stevens RW, Ando K, Nakao K, Okumura Y, Sakakibara M,
Okumura T, Tamura T, Miyamoto K (2003) Novel imidazole
compounds as a new series of potent, orally active inhibitors of
5-lipoxygenase. Bioorg Med Chem 11:3879–3887
Mosmann T (1983) Rapid colorimetric assay for cellular growth and
survival: application to proliferation and cytotoxicity assays.
J Immunol Methods 65:55–63
site of ERa with exactly similar conditions and the docked
conformation having lowest docking energy was aligned
with lasofoxifene in crystallography with ERa (2OUZ),
˚
using Pymol software and RMSD acquired was 1.74 A
showing that the docking method was valid (Ali et al., 2007).
Narasimhan B, Sharma D, Kumar P (2011) Biological importance of
imidazole nucleus in the new millennium. Med Chem Res
20:1119–1140
Acknowledgments We like to thank Deputy of Research, School of
Pharmacy, Shahid Beheshti University of Medical Sciences for
financial support of this study as a part of PhD thesis of Sara Arfaei.
Newman MJ, Rodarte JC, Benbatoul KD, Romano SJ, Zhang C,
Krane S, Moran EJ, Uyeda RT, Dixon R, Guns ES, Mayer LD
(2000) Discovery and characterization of OC144-093, a novel
inhibitor of P-glycoprotein-mediated multidrug resistance. Can-
cer Res 60:2964–2972
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