Synthesis, biological evaluation, and molecular docking studies of cinnamic acyl 1,3,4-thiadiazole amide derivatives as novel antitubulin agents

Article abstract of DOI:10.1016/j.bmc.2011.12.057

A series of cinnamic acyl 1,3,4-thiadiazole amide derivatives (6a-10e) have been designed and synthesized, and their biological activities were also evaluated as potential antiproliferation and tubulin polymerization inhibitors. Among all the compounds, 10e showed the most potent activity in vitro, which inhibited the growth of MCF-7 and A549 cell lines with IC₅₀ values of 0.28 and 0.52 μg/mL, respectively. Compound 10e also exhibited significant tubulin polymerization inhibitory activity (IC₅₀ = 1.16 μg/mL). Docking simulation was performed to insert compound 10e into the crystal structure of tubulin at colchicine binding site to determine the probable binding model. Based on the preliminary results, compound 10e with potent inhibitory activity in tumor growth may be a potential anticancer agent.

Full text of DOI:10.1016/j.bmc.2011.12.057

Bioorganic & Medicinal Chemistry 20 (2012) 1181–1187
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis, biological evaluation, and molecular docking studies of cinnamic
acyl 1,3,4-thiadiazole amide derivatives as novel antitubulin agents
⇑
⇑
Xian-Hui Yang , Qing Wen , Ting-Ting Zhao, Jian Sun, Xi Li, Man Xing, Xiang Lu , Hai-Liang Zhu
State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People’s Republic of 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 cinnamic acyl 1,3,4-thiadiazole amide derivatives (6a–10e) have been designed and synthe-
sized, and their biological activities were also evaluated as potential antiproliferation and tubulin poly-
merization inhibitors. Among all the compounds, 10e showed the most potent activity in vitro, which
Received 4 December 2011
Revised 28 December 2011
Accepted 28 December 2011
Available online 5 January 2012
inhibited the growth of MCF-7 and A549 cell lines with IC50 values of 0.28 and 0.52
l
g/mL, respectively.
g/mL).
Compound 10e also exhibited significant tubulin polymerization inhibitory activity (IC50 = 1.16
l
Docking simulation was performed to insert compound 10e into the crystal structure of tubulin at colchi-
cine binding site to determine the probable binding model. Based on the preliminary results, compound
10e with potent inhibitory activity in tumor growth may be a potential anticancer agent.
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Cinnamic acyl 1,3,4-thiadiazole amide
derivatives
Antitubulin polymerization
Structure–activity relationship
Molecular docking
1. Introduction
ing useful intermediates in several organic preparations,25–28 and
are extensively investigated for their anticancer activity due to
Cancer is one of the most serious threats against human health in
the world, and the clinical prognosis remains relatively poor. Strat-
egies to block cell division by affecting the mitotic spindle have his-
torically been a successful area of research for the advancement of
cancer drugs.1,2 For example, Colchicine (Fig. 1) is the first drug that
is well known to bind tubulin, and the colchicine binding site has
been characterized recently.3 Combretastatin A-4 (CA-4) (Fig. 1),
which was isolated from the South African tree Combretum caffrum,
was found to inhibit the polymerization of tubulin by binding to the
colchicine site.4,5 The development of ketones as tubulin binding
agents such as chalcones was reviewed.6
their therapeutic potential.29–31 Furthermore, thiazoles and oxadi-
azoles, both being five-membered heterocycle, displayed potent
biological activities and low toxicities in previous reports. Among
them, some compounds showed their anticancer effects by inhibit-
ing tubulin to form microtubule, such as compound A and
A-105972 (Fig. 1).32,33 As is known thiadiazoles are the bioisosters
of thiazoles and oxadiazoles, it is supposed that thiadiazoles may
also be a potential antitubulin agent.
These previous researches encouraged us to integrate cinnamon
amide with thiadiazoles to screen new cinnamic acyl 1,3,4-thiadi-
azole amides as potential antitubulin agents. The two combined
substructures, cinnamon amide and thiadiazoles, might exhibit
synergistic effect in anticancer activities. The objectives of the
present work are (1) to synthesize new cinnamic acyl 1,3,4-thiadi-
azole amides; (2) to evaluate their anticancer and antitubulin
activities; (3) to explore the preliminary mechanism of their role
in cell division cycle and (4) to investigate the potential inhibitor’s
interaction with tubulin by docking study.
Chalcones are an important pharmacophore of various natural
products and synthetic precursors including flavonoids and isofl-
avonoids. A variety of pharmacological activities of chalcones have
been reported, including anticancer,7–9 anti-inflammatory,10,11
anti-tuberculosis,12 anti-fungal and antiproliferative activities.
13–19
Their broad biological properties are largely due to the
a
,b-unsaturated ketone moiety.20 Cinnamon amide owns the sim-
ilar part,
a,b-unsaturated ketone moiety (Fig. 2), and cinnamoyl
moiety was found in a variety of biologically active substances,21,22
antitubulin activities of various cinnamoyl derivatives were also
explored.23,24
2. Results and discussion
2.1. Chemistry
On the other hand, thiadiazoles have gained prominence by
exhibiting a wide variety of biological activities as well as produc-
The synthetic route of the cinnamic acyl 1,3,4-thiadiazole amide
derivatives 6a–10e is outlined in Scheme 1. These compounds were
synthesized from 2-amino- 1,3,4-thiadiazoles 6–10 and cinnamic
acids a–e. Firstly, the different substituted benzoic acid 1–5 were
treated with thiosemicarbazide in presence of phosphoryl chloride
⇑
Corresponding authors. Tel.: +86 25 8359 2572; fax: +86 25 8359 2672.
E-mail address: zhuhl@nju.edu.cn (H.-L. Zhu).
These two authors equally contributed to this paper.
0968-0896/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2011.12.057

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X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
Figure 1. Chemical structures of antimitotic agents and lead tubulin inhibitors.
yielded 2-amino-1,3,4-thiadiazoles. Secondly, compounds a–e were
prepared according to the procedure reported by Davis et al. with
some modifications.34 Aromatic aldehydes and malonic acid were
dissolved in a mixture of pyridine and piperidine and refluxed for
12 h, and cinnamic acids were obtained with yields of 80–90%.
Thirdly, the coupling reaction between the obtained different
substituted 2-amino-1,3,4-thiadiazoles and cinnamic acids was per-
formed by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide
hydrochloride (EDCl) and N-hydroxybenzotriazole (HOBt) in anhy-
drous methylene dichloride, and refluxed to give the desired com-
pounds 6a–10e (Table 1). Among these compounds, 6c, 7b–7e,
8b–8e, 9b–9e and 10b–10e are reported for the first time. All of
the synthetic compounds gave satisfactory elementary analytical
and spectroscopic data. 1H NMR and ESI-MS spectra were consistent
with the assigned structures.
Structure–activity relationships in these cinnamic acyl 1,3,4-
thiadiazole amides derivatives demonstrated that compounds with
para electron-donating substituents (9a,10a) showed more potent
activities than those with electron-withdrawing substituents (7a,
8a) in the A-ring. A comparison of the para-substituents on the
A-ring demonstrated that an electron-donating group (9a,10a)
have slightly improved antiproliferative activity and the potency
order is OMe > Me, whereas a Cl (7a) and Br (8a) group substituent
had minimal effects compared with 6a. In the case of constant A-
ring substituents, change of substituents on B-ring could also affect
the activities of these compounds. Among the compounds 10a–
10e, these compounds ( 10d, 10e) with para electron-donating
substituted showed stronger anticancer activity and the strength
order was similar with A-ring: OMe > Me, followed that 10b and
10c led to a noteworthy poor activity. Among all the compounds,
10e with para- OMe group in the both A-ring and B-ring showed
the best activity. To examine whether the compounds interact with
tubulin and inhibit tubulin polymerization, we performed the
tubulin in vitro assembly assay. As shown in Table 2, compounds
9e, 10d and 10e showed strong inhibitory effect and their 50%
2.2. Bioactivity
To test the anticancer activities of the synthesized compounds,
we evaluated antiproliferative activities of compounds 6a–10e
against MCF-7 and A549 cells. The results were summarized in
Table 2. These 1,3,4-thiadiazole compounds bearing the cinnamoyl
moiety showed remarkable antiproliferative effects. Among them,
compound 10e displayed the most potent inhibitory activity
tubulin polymerization inhibition about 2.64
1.16 g/mL, respectively (the positive control colchicine with an
IC50 of 1.72 g/mL for tubulin). Compound 10e displayed the most
lg/mL, 2.56 lg/mL,
l
l
potent anti-tubulin polymerization activity. This result indicated
the anti-proliferative effect was possibly produced by direct con-
nection of tubulin and the compound.
Furthermore, compound 10e was further assayed for their ef-
fects on cell cycle using flow cytometry (Fig. 3). As shown in Figure
3, 68% of these cells were arrested at G2/M period after treatment
(IC50 = 0.28
comparable to the positive control colchicine (IC50 = 0.53
for MCF-7, IC50 = 0.75 g/mL for A549, respectively).
l
g/mL for MCF-7 and IC50 = 0.52
l
g/mL for A549),
l
g/mL
l
with 10e of 5 lg/mL for 24 h. These findings indicated a continuing
impairment of cell division and confirmed compound 10e was a
potent antitubulin agent.
To gain better understanding on the potency of the studied
compounds and guide further SAR studies, we proceeded to exam-
ine the interaction of compound 10e with tubulin crystal structure
(PDB code: 1SA0). The molecular docking was performed by insert-
ing compound 10e into the colchicine binding site of tubulin. All
docking runs were applied LigandFit Dock protocol of Discovery
Studio 3.1. The binding modes of compound 10e and tubulin were
depicted in Figure 4. All the amino acid residues which had inter-
Figure 2. Similar part of cinnamon amide and colchicine.

X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
1183
NH2
O
S
NH
C
N
S
COOH
N
S
a
H2N
+
N
N
H
NH2
c
R1
N
R1
6-10
1-5
R1
COOH
CHO
6a-10e
R2
b
+
HOOC
COOH
R2
R2
a-e
Scheme 1. General synthesis of cinnamic acyl 1,3,4-thiadiazole amide derivatives (6a–10e). Reagents and conditions: (a) POCl3, reflux, 8 h, 50% NaOH; (b) piperidine,
pyridine, 80–90 °C, 12 h; (c) EDCl, HOBt, dichloromethane, reflux, 8 h.
Table 1
Structure of compounds 6a–10e
O
NH
C
S
N
N
A
B
R1
R2
Compounds
6a
6b
6c
6d
6e
7a
7b
7c
7d
7e
R1
R2
H
H
8a
Br
H
10a
OCH3
H
H
F
H
CF3
8c
Br
CF3
10c
H
CH3
8d
H
OCH3
8e
Cl
H
9a
CH3
H
Cl
F
9b
CH3
F
Cl
CF3
9c
CH3
CF3
Cl
CH3
9d
CH3
CH3
Cl
OCH3
9e
CH3
OCH3
Compounds
R1
R2
Compounds
R1
R2
8b
Br
F
10b
OCH3
F
Br
Br
CH3
10d
OCH3
CH3
OCH3
10e
OCH3
OCH3
OCH3
CF3
actions with tubulin were exhibited in Figure 4c. In the binding
mode, compound 10e is nicely bound to the colchicine binding site
of tubulin via hydrophobic interactions and binding is stabilized by
tory activities. Among all of the compounds, 10e showed the most
potent inhibition activity which inhibited the growth of MCF-7 and
A549 cell lines with IC50 values of 0.28 and 0.52
lg/mL and inhib-
two hydrogen bonds and two
p
-cation interactions. The nitrogen
ited the polymerization of tubulin with IC50 of 1.16 l
g/mL. Molec-
atom of the amide bond formed one hydrogen bond with the ami-
no hydrogen of Thr C:179 (bond length: Thr179 N–HÁ Á ÁN = 2.774 Å;
bond angle: Thr179 N–HÁ Á ÁN = 154.4°) and the oxygen atom of one
of the methoxyl groups on B-ring of 10e formed another one with
the amino hydrogen of Lys D:254 (bond length: Lys D:254 N–
HÁ Á ÁO = 2.232 Å; bond angle: Lys D:254 N–HÁ Á ÁO = 151.8°). The en-
zyme surface model was showed in Figure 4a, which revealed that
the molecule was well embedded in the active pocket. Overall,
these results of the molecular docking study showed that the
1,3,4-thiadiazole skeleton and cinnamon amide could act synergis-
tically to interact with the colchicine binding site of tubulin, sug-
gesting that compound 10e is a potential inhibitor of tubulin.
ular docking was further performed to study the inhibitor-tubulin
protein interactions. After analysis of the binding model of com-
pound 10e with tubulin, it was found that two hydrogen bond
and two p-cation interaction with the protein residues in the col-
chicine binding site might play a crucial role in its antitubulin poly-
merization and antiproliferative activities. The information of this
work might be helpful for the design and synthesis of tubulin poly-
merization inhibitors with stronger activities.
4. Experiments
4.1. Materials and measurements
3. Conclusion
All chemicals and reagents used in the current study were of
analytical grade. All the 1H NMR spectra were recorded on a Bruker
DPX300 model Spectrometer in DMSO-d6 and chemical shifts were
reported in ppm (d). ESI-MS spectra were recorded on a Mariner
System 5304 Mass spectrometer. Elemental analyses were per-
formed on a CHN-O-Rapid instrument. TLC was performed on the
glassbacked silica gel sheets (Silica Gel 60 GF254) and visualized
In this study, a series of novel antitubulin polymerization inhib-
itors (6a–10e) bearing 1,3,4-thiadiazole skeleton and cinnamon
amide had been synthesized and evaluated their biological activi-
ties. These compounds exhibited potent antiproliferative activities
against MCF-7 and A549 cells and tubulin polymerization inhibi-

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X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
Table 2
75–80 °C for 6 h. After cooling down to room temperature, water
was added. The reaction mixture was refluxed for 1 h. After cool-
ing, the mixture was basified to pH 8–9 by the dropwise addition
of 50% NaOH solution under ice bath. The precipitate was filtered
and recrystallized from ethanol to gain compounds 6–10.
Inhibition (IC50) of MCF-7 and A549 cells proliferation and inhibition of tubulin
polymerization by compounds 6a–10e
Compound
IC50 SD (
lg/mL)
MCF-7a
A549a
Tubulinb
6a
6b
6c
6d
6e
7a
7b
7c
7d
7e
8a
8b
8c
8d
8e
9a
9b
9c
9d
9e
10a
10b
10c
10d
10e
Colchicine
CA-4
1.47 0.17
1.45 0.19
1.52 0.12
1.23 0.19
0.83 0.08
1.42 0.14
1.58 0.15
1.65 0.09
1.44 0.14
0.91 0.09
1.50 0.07
1.49 0.08
1.58 0.13
1. 32 0.13
1.13 0.11
1.19 0.06
1.27 0.07
1.10 0.05
0.61 0.07
0.35 0.05
0.78 0.06
0.85 0.07
0.79 0.05
0.31 0.03
0.28 0.02
0.53 0.07
0.41 0.04
1.75 0.15
1.82 0.12
1.78 0.18
1.58 0.09
0.76 0.07
2.02 0.21
2.06 0.26
3.09 0.24
1.25 0.12
1.38 0.07
2.18 0.15
2.83 0.18
4.68 0.32
1.51 0.13
1.04 0.08
1.38 0.09
1.23 0.14
1.61 0.16
1.08 0.10
0.66 0.05
0.68 0.08
0.75 0.11
0.69 0.10
0.58 0.05
0.52 0.06
0.75 0.08
0.55 0.04
5.68 0.74
5.87 0.58
5.52 0.54
4.49 0.35
3.02 0.42
6.56 0.86
7.08 0.97
7.83 1.05
4.79 0.55
5.68 0.60
7.05 0.85
8.66 1.03
10.6 1.66
5.02 0.72
4.11 0.53
4.83 0.41
5.08 0.68
5.16 0.63
4.15 0.62
2.64 0.28
3.08 0.33
3.05 0.45
3.17 0.47
2.56 0.31
1.16 0.36
1.72 0.18
0.81 0.09
4.3. General procedure for synthesis of cinnamic acids
A mixture of aromatic aldehydes (10 mmol), malonic acid
(12 mmol), piperidine (12 mmol) was dissolved in pyridine and
stirred on 80–90 °C for 12 h. The pyridine was removed at the vac-
uum. The reaction mixture was poured into ice water. And the pre-
cipitate was filtered and washed with 10% HCl, and dried under
vacuum to afford the cinnamic acids a–e.
4.4. General procedure for synthesis of target compounds 6a–
10e
Compounds 6a–10e were synthesized by coupling substituted
2-amino-1,3,4-thiadiazoles with cinnamic acids, using 1-ethyl-3-
(3-dimethylaminopropyl) carbodiimide hydrochloride (EDCl) and
N-hydroxybenzotriazole (HOBt) as condensing agent. The mixture
was refluxed in anhydrous CH2Cl2 for 8–10 h. The products were
extracted with ethyl acetate. The extract was washed successively
with 10% HCl, saturated NaHCO3 and water, respectively, then
dried over anhydrous Na2SO4, filtered and evaporated. The residue
was purified by column chromatography using petroleum ether
and ethyl acetate (3:1).
a
Inhibition of the growth of tumor cell lines.
Inhibition of tubulin polymerization.
b
4.4.1. N-(5-Phenyl-1,3,4-thiadiazol-2-yl)cinnamamide (6a)
White powders, yield 80%, mp: 326–328 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 6.97 (d, J = 15.93 Hz, 1H); 7.47–7.51 (m, 3H);
7.54–7.57 (m, 3H); 7.66–7.69 (m, 2H); 7.82 (d, J = 15.72 Hz, 1H);
7.95–7.99 (m, 2H); 12.89 (s, 1H). ESI-MS: 308.37 (C17H14N3OS,
[M+H]+). Anal. Calcd for C17H13N3OS: C, 66.43; H, 4.26; N, 13.67;
Found: C, 66.31; H, 4.28; N, 13.71.
in UV light (254 nm). Column chromatography was performed
using silica gel (200–300 mesh) eluting with ethyl acetate and
petroleum ether.
4.2. General procedure for synthesis of 2-amino-1,3,4-
thiadiazoles
4.4.2. (E)-3-(4-Fluorophenyl)-N-(5-phenyl-1,3,4-thiadiazol-2-
yl)acrylamide (6b)
White powders, yield 84%, mp: 348–350 °C, 1H NMR(300 MHz,
DMSO-d6, d ppm): 6.90 (d, J = 15.72 Hz, 1H); 7.33 (t, J = 8.87 Hz,
A stirring mixture of substituted benzoic acid (10 mmol),
thiosemicarbazide (10 mmol) and POCl3 (10 mL) was heated at
Figure 3. Effects of compound 10e on cell cycle progression of MCF-7 cells were determined by flow cytometry analysis. MCF-7 cells were treated with 10e for 24 h. The
percentage of cells in each cycle phase was indicated.

X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
1185
Figure 4. (a) The surface model structure of compound 10e binding model with tubulin complex. (b) Compound 10e (colored by atom: carbons: gray; nitrogen: blue; oxygen:
red; sulfur: yellow) is bond into tubulin (entry 1SA0 in the Protein Data Bank). The dotted lines show the hydrogen bonds and the yellow line show the -cation interactions.
p
Thr C: 179 is the mean of Thr: 179 in C chain. (c) 2D Ligand interaction diagram of compound 10e with tubulin using Discovery Studio program with the essential amino acid
residues at the binding site are tagged in circles. The purple circles show the amino acids which participate in hydrogen bonding, electrostatic or polar interactions and the
green circles show the amino acids which participate in the Van der Waals interactions.
2H); 7.54 (t, J = 2.84 Hz, 3H); 7.75 (t, J = 7.23 Hz, 2H); 7.82 (d,
J = 15.72 Hz, 1H); 7.96–7.99 (m, 2H); 12.90 (s, 1H). ESI-MS:
326.36 (C17H13FN3OS, [M+H]+). Anal. Calcd for C17H12FN3OS: C,
62.76; H, 3.72; N, 12.91; Found: C, 62.65; H, 3.75; N, 12.98.
J = 8.58 Hz, 2H); 7.54 (t, J = 2.84 Hz, 3H); 7.63 (d, J = 8.58 Hz, 2H);
7.76 (d, J = 15.75 Hz,1H); 7.94–7.98 (m, 2H); 12.79 (s, 1H). ESI-
MS: 338.40 (C18H16N3O2S, [M+H]+). Anal. Calcd for C18H15N3O2S:
C, 64.08; H, 4.48; N, 12.45; Found: C, 64.21; H, 4.45; N, 12.51.
4.4.3. (E)-N-(5-Phenyl-1,3,4-thiadiazol-2-yl)-3
4.4.6. N-(5-(4-Chlorophenyl)-1,3,4-thiadiazol-2-
-(4-(trifluoromethyl)phenyl)acrylamide (6c)
yl)cinnamamide (7a)
White powders, yield 75%, mp: 315–316 °C, 1H NMR(300 MHz,
DMSO-d6, d ppm): 7.08 (d, J = 15.93 Hz, 1H); 7.54 (t, J = 2.93 Hz,
3H); 7.82–7.91 (m, 5H); 7.96 (t, J = 2.93 Hz, 2H); 12.96 (s, 1H).
ESI-MS: 376.37 (C18H13F3N3OS, [M+H]+). Anal. Calcd for
C18H12F3N3OS: C, 57.59; H, 3.22; N, 11.19; Found: C, 57.75; H,
3.20; N, 11.14.
White powders, yield 78%, mp: 333–335 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 6.96 (d, J = 15.72 Hz, 1H); 7.38 (t, J = 8.7 Hz, 2H);
7.46–7.51 (m, 3H); 7.65–7.69 (m, 2H); 7.81 (d, J = 16.26 Hz, 1H);
8.00–8.05 (m, 2H); 12.91 (s, 1H). ESI-MS: 342.81 (C17H13ClN3OS,
[M+H]+). Anal. Calcd for C17H12ClN3OS: C, 59.73; H, 3.54; N,
12.29; Found: C, 59.62; H, 3.56; N, 12.25.
4.4.4. (E)-N-(5-Phenyl-1,3,4-thiadiazol-2-yl)-3-(p-
tolyl)acrylamide (6d)
4.4.7. (E)-N-(5-(4-Chlorophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
fluorophenyl)acrylamide (7b)
White powders, yield 87%, mp: 332–334 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.35 (s, 3H); 6.90 (d, J = 15.9 Hz, 1H); 7.29 (d,
J = 8.07 Hz, 2H); 7.53–7.57 (m, 5H); 7.77 (d, J = 15.72 Hz, 1H);
7.95–7.98 (m, 2H); 12.85 (s, 1H). ESI-MS: 322.40 (C18H16N3OS,
[M+H]+). Anal. Calcd for C18H15N3OS: C, 67.27; H, 4.70; N, 13.07;
Found: C, 67.10; H, 4.72; N, 13.12.
White powders, yield 88%, mp: 354–356 °C, 1H NMR(300 MHz,
DMSO-d6, d ppm): 6.90 (d, J = 15.72 Hz, 1H); 7.33 (t, J = 9.0 Hz,
2H); 7.61 (d, J = 8.58 Hz, 2H); 7.73–7.77 (m, 2H); 7.82 (d,
J = 15.9 Hz, 1H); 8.00 (d, J = 8.61 Hz, 2H); 12.94 (s, 1H). ESI-MS:
360.81 (C17H12ClFN3OS, [M+H]+). Anal. Calcd for C17H11ClFN3OS:
C, 56.75; H, 3.08; N, 11.68; Found: C, 56.86; H, 3.10; N, 11.64.
4.4.5. (E)-3-(4-Methoxyphenyl)-N-(5-phenyl-1,3,4-thiadiazol-2-
yl)acrylamide (6e)
4.4.8. (E)-N-(5-(4-Chlorophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
(trifluoromethyl)phenyl)acrylamide (7c)
White powders, yield 83%, mp:308–311 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.82 (s, 3H); 6.81 (d, J = 15.75 Hz, 1H); 7.04 (d,
White powders, yield 83%, mp: 328–330 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 7.06 (d, J = 15.90 Hz, 1H); 7.38 (t, J = 8.78 Hz,

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X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
2H); 7.82–7.90 (m, 5H); 8.00–8.05 (m, 2H); 13.00 (s, 1H). ESI-MS:
410.81 (C18H12ClF3N3OS, [M+H]+). Anal. Calcd for C18H11ClF3N3OS:
C, 52.75; H, 2.71; N, 10.25; Found: C, 52.81; H, 2.72; N, 10.20.
4.4.16. N-(5-(P-tolyl)-1,3,4-thiadiazol-2-yl)cinnamamide (9a)
White powders, yield 84%, mp: 322–324 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.38 (s, 3H); 6.96 (d, J = 15.93 Hz, 1H); 7.35 (d,
J = 7.86 Hz, 2H); 7.48 (d, J = 2.48 Hz, 3H); 7.67 (d, J = 3.84 Hz, 2H);
7.83 (t, J = 12.81 Hz, 3H); 12.86 (s, 1H). ESI-MS: 322.40
(C18H16N3OS, [M+H]+). Anal. Calcd for C18H15N3OS: C, 67.27; H,
4.70; N, 13.07; Found: C, 67.38; H, 4.71; N, 13.13.
4.4.9. (E)-N-(5-(4-Chlorophenyl)-1,3,4-thiadiazol-2-yl)-3-(p-
tolyl)acrylamide (7d)
White powders, yield 81%, mp: 333–334 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.35 (s, 3H); 6.90 (d, J = 15.93 Hz, 1H); 7.29 (d,
J = 8.04 Hz, 2H);7.39 (t, J = 8.88 Hz, 2H); 7.56 (d, J = 8.22 Hz, 2H);
7.77 (d, J = 15.72 Hz, 1H); 8.00–8.05 (m, 2H); 12.85 (s, 1H). ESI-
MS: 356.84 (C18H15ClN3OS, [M+H]+). Anal. Calcd for C18H14ClN3OS:
C, 60.76; H, 3.97; N, 11.81; Found: C, 60.81; H, 3.99; N, 11.86.
4.4.17. (E)-3-(4-Fluorophenyl)-N-(5-(p-tolyl)-1,3,4-thiadiazol-2-
yl)acrylamide (9b)
White powders, yield 86%, mp: 340–342 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.38 (s, 3H); 6.89 (d, J = 15.75 Hz, 1H); 7.29–7.36
(m, 4H); 7.71–7.86 (m,5H); 12.84 (s, 1H). ESI-MS: 340.39
(C18H15FN3OS, [M+H]+). Anal. Calcd for C18H14FN3OS: C, 63.70; H,
4.16; N, 12.38; Found: C, 63.62; H, 4.15; N, 12.44.
4.4.10. (E)-N-(5-(4-Chlorophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
methoxyphenyl)acrylamide (7e)
White powders, yield 76%, mp: 330–332 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.82 (s, 3H); 6.81 (d, J = 15.72 Hz, 1H); 7.04 (d,
J = 8.58 Hz, 2H); 7.38 (t, J = 7.78 Hz, 2H); 7.63 (d, J = 8.58 Hz, 2H);
7.76 (d, J = 15.90 Hz,1H); 8.00–8.04 (m, 2H); 12.79 (s, 1H). ESI-MS:
372.84 (C18H15ClN3O2S, [M+H]+). Anal. Calcd for C18H14ClN3O2S: C,
58.14; H, 3.79; N, 11.30; Found: C, 58.08; H, 3.80; N, 11.34.
4.4.18. (E)-N-(5-(P-tolyl)-1,3,4-thiadiazol-2-yl)-3-(4-
(trifluoromethyl)phenyl)acrylamide (9c)
White powders, yield 83%, mp: 345–347 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.38 (s, 3H); 7.07 (d, J = 15.90 Hz, 1H); 7.35 (d,
J = 8.22 Hz, 2H); 7.84–7.90 (m, 7H); 12.97 (s, 1H). ESI-MS: 390.39
(C19H15F3N3OS, [M+H]+). Anal. Calcd for C19H14F3N3OS: C, 58.60;
H, 3.62; N, 10.79; Found: C, 58.69; H, 3.64; N, 10.75.
4.4.11. N-(5-(4-Bromophenyl)-1,3,4-thiadiazol-2-
yl)cinnamamide (8a)
White powders, yield 87%, mp: 351–353 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 6.96 (d, J = 15.72 Hz, 1H); 7.47–7.49 (m, 3H);
7.66–7.69 (m,2H); 7.74 (d, J = 8.61 Hz, 2H); 7.82 (d, J = 15.72 Hz,
1H); 7.92 (t, J = 4.31 Hz, 2H); 12.92 (s, 1H). ESI-MS: 387.27
(C17H13BrN3OS, [M+H]+). Anal. Calcd for C17H12BrN3OS: C, 52.86;
H, 3.13; N, 10.88; Found: C, 52.95; H, 3.12; N, 10.93.
4.4.19. (E)-3-(P-tolyl)-N-(5-(p-tolyl)-1,3,4-thiadiazol-2-
yl)acrylamide (9d)
White powders, yield 86%, mp: 330–332 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.36 (d, J = 6.96 Hz, 6H); 6.89 (d, J = 15.90 Hz,
1H); 7.29 (d, J = 8.04 Hz, 2H); 7.35 (d, J = 8.04 Hz, 2H); 7.56 (d,
J = 8.22 Hz, 2H); 7.76 (d, J = 15.72 Hz, 1H); 7.85 (d, J = 8.25 Hz,
2H); 12.81 (s, 1H). ESI-MS: 336.42 (C19H18N3OS, [M+H]+). Anal.
Calcd for C19H17N3OS: C, 68.03; H, 5.11; N, 12.53; Found: C,
68.16; H, 5.13; N, 12.48.
4.4.12. (E)-N-(5-(4-Bromophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
fluorophenyl)acrylamide (8b)
White powders, yield 90%, mp: 357–359 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 6.90 (d, J = 16.11 Hz, 1H); 7.32 (t, J = 8.58 Hz,
2H); 7.72–7.76 (m,4H); 7.82 (d, J = 15.72 Hz, 1H); 7.92 (d,
J = 8.58 Hz, 2H); 12.94 (s, 1H). ESI-MS: 405.26 (C17H12BrFN3OS,
[M+H]+). Anal. Calcd for C17H11BrFN3OS: C, 50.51; H, 2.74; N,
10.39; Found: C, 50.57; H, 2.75; N, 10.36.
4.4.20. (E)-3-(4-Methoxyphenyl)-N-(5-(p-tolyl)-1,3,4-thiadiazol-
2-yl)acrylamide (9e)
White powders, yield 92%, mp: 318–320 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.38 (s, 3H); 3.82 (s, 3H); 6.80 (d, J = 15.75 Hz,
1H); 7.04 (d, J = 8.79 Hz, 2H); 7.35 (d, J = 8.22 Hz, 2H); 7.62 (d,
J = 8.97 Hz, 2H); 7.76 (d, J = 15.90 Hz,1H); 7.84 (d, J = 8.22 Hz,2H);
12.75 (s, 1H). ESI-MS: 352.42 (C19H18N3O2S, [M+H]+). Anal. Calcd
for C19H17N3O2S: C, 64.94; H, 4.88; N, 11.96; Found: C, 64.80; H,
4.86; N, 11.92.
4.4.13. (E)-N-(5-(4-Bromophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
(trifluoromethyl)phenyl)acrylamide (8c)
White powders, yield 88%, mp: 338–340 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 7.07 (d, J = 15.90 Hz, 1H); 7.75 (d, J = 8.61 Hz,
2H); 7.86 (t, J = 6.95 Hz, 4H); 7.93 (d, J = 8.61 Hz, 3H); 13.05 (s,
1H). ESI-MS: 455.26 (C18H12BrF3N3OS, [M+H]+). Anal. Calcd for
4.4.21. N-(5-(4-Methoxyphenyl)-1,3,4-thiadiazol-2-
yl)cinnamamide (10a)
C
18H11BrF3N3OS: C, 47.59; H, 2.44; N, 9.25; Found: C, 47.51; H,
White powders, yield 81%, mp: 318–320 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.84 (s, 3H); 6.96 (d, J = 15.72 Hz, 1H); 7.10 (d,
J = 8.97 Hz, 2H); 7.48 (t, J = 2.57 Hz, 3H); 7.65–7.69 (m, 2H); 7.80
(d, J = 15.72 Hz, 1H); 7.91 (d, J = 8.79 Hz, 2H); 12.82 (s, 1H). ESI-
MS: 338.40 (C18H16N3O2S, [M+H]+). Anal. Calcd for C18H15N3O2S:
C, 64.08; H, 4.48; N, 12.45; Found: C, 64.01; H, 4.51; N, 12.41.
2.43; N, 9.31.
4.4.14. (E)-N-(5-(4-Bromophenyl)-1,3,4-thiadiazol-2-yl)-3-(p-
tolyl)acrylamide (8d)
White powders, yield 82%, mp: 341–343 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.34 (s, 3H); 6.89 (d, J = 15.72 Hz, 1H); 7.28 (d,
J = 7.86 Hz, 2H); 7.55 (d, J = 8.04 Hz, 2H); 7.75 (t, J = 11.34 Hz,
3H); 7.91 (d, J = 8.40 Hz, 2H); 12.88 (s, 1H). ESI-MS: 401.29
(C18H15BrN3OS, [M+H]+). Anal. Calcd for C18H14BrN3OS: C, 54.01;
H, 3.53; N, 10.50; Found: C, 54.08; H, 3.51; N, 10.57.
4.4.22. (E)-3-(4-Fluorophenyl)-N-(5-(4-methoxyphenyl)-1,3,4-
thiadiazol-2-yl)acrylamide (10b)
White powders, yield 84%, mp: 321–323 °C, 1H NMR(300 MHz,
DMSO-d6, d ppm): 3.84 (s, 3H); 6.90 (d, J = 15.90 Hz, 1H); 7.10 (d,
J = 8.61 Hz, 2H); 7.33 (t, J = 8.60 Hz, 2H); 7.74 (t, J = 7.23 Hz, 2H); 7.81
(d, J = 15.90 Hz, 1H); 7.91 (d, J = 8.58 Hz, 2H); 12.82 (s, 1H). ESI-MS:
356.39 (C18H15FN3O2S, [M+H]+). Anal. Calcd for C18H14FN3O2S: C,
60.83; H, 3.97; N, 11.82; Found: C, 60.90; H, 3.96; N, 11.88.
4.4.15. (E)-N-(5-(4-Bromophenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
methoxyphenyl)acrylamide (8e)
White powders, yield 77%, mp: 336–338 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.82 (s, 3H); 6.80 (d, J = 15.75 Hz, 1H); 7.04 (d,
J = 8.79 Hz, 2H); 7.63 (t, J = 8.94 Hz, 2H); 7.73–7.79 (m, 3H); 7.91
(d, J = 8.43 Hz, 2H); 12.83 (s, 1H). ESI-MS: 417.29 (C18H15BrN3O2S,
[M+H]+). Anal. Calcd for C18H14BrN3O2S: C, 51.93; H, 3.39; N, 10.09;
Found: C, 51.80; H, 3.38; N, 10.04.
4.4.23. (E)-N-(5-(4-Methoxyphenyl)-1,3,4-thiadiazol-2-yl)-3-(4-
(trifluoromethyl)phenyl)acrylamide (10c)
White powders, yield 76%, mp: 336–338 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.84 (s, 3H); 7.07 (d, J = 15.90 Hz, 1H); 7.10 (d,

X.-H. Yang et al. / Bioorg. Med. Chem. 20 (2012) 1181–1187
1187
J = 8.61 Hz, 2H); 7.84–7.89 (m, 4H); 7.95 (d, J = 8.58 Hz, 3H); 12.92(s,
The molecular docking procedure was performed by using
LigandFit protocol within Discovery Studio 3.1. For ligand prepara-
tion, the 3D structures of 10e was generated and minimized using
Discovery Studio 3.1. For protein preparation, the hydrogen atoms
were added, and the water and impurities were removed. The whole
tubulin was defined as a receptor and the site sphere was selected
based on the ligand binding location of colchicine, then the colchi-
cine molecule was removed and 10e was placed during the molecu-
lar docking procedure. Types of interactions of the docked protein
with ligand were analyzed after the end of molecular docking.
1H) ESI-MS: 406.39 (C19H15F3N3O2S, [M+H]+). Anal. Calcd for
C19H14F3N3O2S: C, 56.29; H, 3.48; N, 10.37; Found: C, 56.21; H,
3.49; N, 10.43.
4.4.24. (E)-N-(5-(4-Methoxyphenyl)-1,3,4-thiadiazol-2-yl)-3-(p-
tolyl)acrylamide(10d)
White powders, yield 80%, mp: 319–321 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 2.35 (s, 3H); 3.84 (s, 3H); 6.89 (d, J = 15.90 Hz,
1H); 7.09 (d, J = 8.79 Hz, 2H); 7.29 (d, J = 8.04 Hz, 2H); 7.56 (d,
J = 8.04 Hz, 2H); 7.76 (d, J = 15.54 Hz, 1H); 7.90 (d, J = 8.79 Hz, 2H);
12.77 (s, 1H). ESI-MS: 352.42 (C19H18N3O2S, [M+H]+). Anal. Calcd
for C19H17N3O2S: C, 64.94; H, 4.88; N, 11.96; Found: C, 64.80; H,
4.89; N, 11.92.
References and notes
1. Honore, S.; Pasquier, E.; Braguer, D. Cell. Mol. Life Sci. 2005, 62, 3039.
2. Pellegrini, F.; Budman, D. R. Cancer Invest. 2005, 23, 264.
3. Ravelli, R. B.; Gigant, B.; Curmi, P. A.; Jourdain, I.; Lachkar, S.; Sobel, A.;
Knossow, M. Nature 2004, 428, 198.
4. Pettit, G. R.; Singh, S. B.; Hamel, E.; Lin, C. M.; Alberts, D. S.; Garcia-Kendall, D.
Experentia 1989, 45, 209.
5. Lin, C. M.; Ho, H. H.; Pettit, G. R.; Hamel, E. Biochemistry 1989, 28, 6984.
6. Lawrence, N. J.; McGown, A. T. Curr. Pharm. Des. 2005, 11, 1679.
7. Park, E. J.; Park, H. R.; Lee, J. S.; Kim, J. Planta Med. 1998, 64, 464.
8. Claude, A. C.; Jean, C. L.; Patric, T.; Christelle, P.; Gerard, H.; Albert, J. C.; Jean, L.
D. Anticancer Res. 2001, 21, 3949.
4.4.25. (E)-3-(4-Methoxyphenyl)-N-(5-(4-methoxyphenyl)-
1,3,4-thiadiazol-2-yl)acrylamide (10e)
White powders, yield 74%, mp: 308–310 °C, 1H NMR (300 MHz,
DMSO-d6, d ppm): 3.84 (s, 6H); 6.80 (d, J = 15.75 Hz, 1H); 7.02–7.10
(m, 4H); 7.62 (d, J = 8.43 Hz, 2H); 7.74 (d, J = 15.93 Hz, 1H); 7.89 (d,
J = 8.79 Hz, 2H); 12.70 (s, 1H). ESI-MS: 368.42 (C19H18N3O3S,
[M+H]+). Anal. Calcd for C19H17N3O3S: C, 62.11; H, 4.66; N, 11.44;
Found: C, 62.25; H, 4.68; N, 11.40.
9. Kumar, S. K.; Erin, H.; Catherine, P.; Halluru, G.; Davidson, N. E.; Khan, S. R. J.
Med. Chem. 2003, 46, 2813.
10. Ko, H. H.; Tsao, L. T.; Yu, K. L.; Liu, C. T.; Wang, J. P.; Lin, C. N. Bioorg. Med. Chem.
2003, 11, 105.
11. Herencia, F.; Ferrandiz, M. L.; Ubeda, A.; Dominguez, J. N.; Charris, J. E.; Lobo, G.
M.; Alcaraz, M. J. Bioorg. Med. Chem. Lett. 1998, 8, 1169.
12. Lin, Y. M.; Zhou, Y.; Flavin, M. T.; Zhou, L. M.; Nie, W.; Chen, F. C. Bioorg. Med.
Chem. 2002, 10, 2795.
13. Lahtchev, K. L.; Batovska, D. I.; Parushev, P., St.; Ubiyvovk, V. M.; Sibirny, A. A.
Eur. J. Med. Chem. 2008, 43, 2220.
14. Boumendjel, A.; Boccard, J.; Carrupt, P.-A.; Nicolle, E.; Blanc, M.; Geze, A.;
Choisnard, L.; Wouessidjewe, D.; Matera, E.-L.; Dumontet, C. J. Med. Chem.
2008, 51, 2307.
15. Cabrera, M.; Simoens, M.; Falchi, G.; Lavaggi, M. L.; Piro, O. E.; Castellano, E. E.;
Vidal, A.; Azqueta, A.; Monge, A.; Lopez de Cerain, A.; Sagrera, G.; Seoane, G.;
Cerecetto, H.; Gonzalez, M. Bioorg. Med. Chem. 2007, 15, 3356.
16. Kim, D. Y.; Kim, K. H.; Kim, N. D.; Lee, K. Y.; Han, C. K.; Yoon, J. H.; Moon, S. K.;
Lee, S. S.; Seong, B. L. J. Med. Chem. 2006, 49, 5664.
17. Go, M. L.; Wu, X.; Liu, X. L. Curr. Med. Chem. 2005, 12, 483.
18. Kerr, D. J.; Hamel, E.; Jung, M. K.; Flynn, B. L. Bioorg. Med. Chem. 2007, 15, 3290.
19. Jung, J. C.; Jang, S.; Lee, Y.; Min, D.; Lim, E.; Jung, H.; Miyeon, Oh.; Seikwan, Oh.;
Jung, M. J. Med. Chem. 2008, 51, 4054.
20. Dimmock, J. R.; Elias, D. W.; Beazely, M. A.; Kandepu, N. M. Curr. Med. Chem.
1999, 6, 1125.
21. Yoshimatsu, K.; Yamaguchi, A.; Yoshino, H.; Koyanagi, N.; Kitoh, K. Cancer Res.
1997, 57, 3208.
22. Hideki Tanaka, H.; Ohshima, N.; Ikenoya, M.; Komori, K.; Katoh, F.; Hidaka, H.
Cancer Res. 2003, 63, 6942.
23. Luo, Y.; Qiu, K. M.; Lu, X.; Liu, K.; Fu, J.; Zhu, H. L. Bioorg. Med. Chem. 2011, 19,
4730.
24. Demetrio, R.; Benedetta, M.; Fabiana, P.; Stella, C.; Salvatore, P.; Maria, V. R.;
Giuseppe, D.; Manlio, T.; Stefania, G.; Antonietta, D. C.; Rosaria, M. P.; Ruoli, B.;
Ernest, H. Eur. J. Med. Chem. 2011, 46, 2786.
25. Sharma, R.; Sainy, J.; Chaturvedi, S. C. Acta Pharm. 2008, 58, 317.
26. Pattanayak, P.; Sharma, R.; Sahoo, P. K. Med. Chem. Res. 2009, 18, 351.
27. Foroumadi, A.; Mansouri, S.; Kiani, Z.; Rahmani, A. Eur. J. Med. Chem. 2003, 38,
851.
28. Zeng, Q.; Bourbeau, M. P.; Wohlhieter, G. E.; Yao, G.; Monenschein, H.; Rider, J.
T.; Lee, M. R.; Zhang, S.; Lofgren, J.; Freeman, D.; Li, C.; Tominey, E.; Huang, X.;
Hoffman, D.; Yamane, H.; Tasker, A. S.; Dominguez, C.; Viswanadhan, V. N.;
Hungate, R.; Zhang, X. Bioorg. Med. Chem. Lett. 2010, 20, 1652.
29. Matysiak, J.; Nasulewicz, A.; Pelczynska, M.; Switalska, M.; Jaroszewicz, I.;
Opolski, A. Eur. J. Med. Chem. 2006, 41, 475.
30. Matysiak, J.; Opolski, A. Bioorg. Med. Chem. 2006, 14, 4483.
31. Zheng, K. B.; He, J.; Zhang, J. Chin. Chem. Lett. 2008, 19, 1281.
32. Romeo, R.; Pier, G. B.; Andrea, B.; Antonio, R.; Ernest, H.; Roberta, B.; Giuseppe,
B.; Giampietro, V. J. Med. Chem. 2011, 54, 5144.
4.5. Antiproliferation assay
The antiproliferative activities of the prepared compounds
against MCF-7 and A549 cells were evaluated as described else-
where with some modifications.35 Target tumor cell lines were
grown to log phase in RPMI 1640 medium supplemented with 10%
fetal bovine serum. After diluting to 2 Â 104cells mLÀ1with the com-
plete medium, 100 lL of the obtained cell suspension was added to
each well of 96-well culture plates. The subsequent incubation was
permitted at 37 °C, 5% CO2 atmosphere for 24 h before the cytotox-
icity assessments. Tested samples at pre-set concentrations were
added to six wells with colchicines and CA-4 co-assayed as positive
references. After 48 h exposure period, 40
2.5 mg mLÀ1 of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-
razolium bromide)) was added to each well. Four hours later, 100
extraction solution (10% SDS-5% isobutyl alcohol-0.01 M HCl) was
added. After an overnight incubation at 37 °C, the optical density
was measured at a wavelength of 570 nm on an ELISA microplate
reader. In all experiments three replicate wells were used for each
drug concentration. Each assay was carried out for at least three
times. The results were summarized in Table 2.
lL of PBS containing
lL
4.6. Effects on tubulin polymerization
Bovine brain tubulin was purified as described previously.36 To
evaluate the effect of the compounds on tubulin assembly in vitro,37
varying concentrations were preincubated with 10 lM tubulin in
glutamate buffer at 30 °C and then cooled to 0 °C. After addition of
GTP, the mixtures were transferred to 0 °C cuvettes in a recording
spectrophotometer and warmed up to 30 °C and the assembly of
tubulin was observed turbid metrically. The IC50 was defined as
the compound concentration that inhibited the extent of assembly
by 50% after 20 min incubation.
33. Bruce, G.; Szczepankiewicz; Gang, L.; Hwan, S. J.; Andrew, S. T.; Indrani, W. G.;
Thomas, W. G.; Stephen, L. G.; Chiou, J. J. Med. Chem. 2001, 44, 4416.
34. Davis, R.; Kumar, N. S.; Abraham, S.; Suresh, C. H.; Rath, N. P.; Tamaoki, N.; Das,
S. J. Phys. Chem. C 2008, 112, 2137.
35. Boumendjel, A.; Boccard, J.; Carrupt, P.-A.; Nicolle, E.; Blanc, M.; Geze, A.;
Choisnard, L.; Wouessidjewe, D.; Matera, E. L.; Dumontet, C. J. Med. Chem. 2008,
51, 2307.
4.7. Docking simulations
The three-dimensional X-ray structure of tubulin (PDB code:
1SA0) was chosen as the template for the modeling study of com-
pound 10e bound to tubulin. The crystal structure was obtained
from the RCSB Protein Data Bank (http://www.rcsb.org/pdb/home/
home.do).
36. Hamel, E.; Lin, C. M. Biochemistry 1984, 23, 4173.
37. Hamel, E. Cell Biochem. Biophys. 2003, 38, 1.