Synthesis and biological evaluation of compounds which contain pyrazole, thiazole and naphthalene ring as antitumor agents

Article abstract of DOI:10.1016/j.bmcl.2014.03.072

A series of compounds which contain pyrazole, thiazole and naphthalene ring (1a-7a, 1b-7b, 1c-7c, 1d-7d) were firstly synthesized and their anti-proliferative activity, EGFR inhibitory activity, cytotoxicity and inhibition to Hela cell migration were evaluated. Compound 2-(3-(3,4- dimethylphenyl)-5-(naphthalen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H) -one (7d) displayed the most potent inhibitory activity (IC₅₀ = 0.86 μM for Hela and IC₅₀ = 0.12 μM for EGFR). Structure-activity relationship (SAR) analysis showed that the anti-proliferative activity was affected by A-ring-substituent (-OCH₃ > -CH₃ > -H > -Br > -Cl > -F). Docking simulation of compound 7d into EGFR active site showed that naphthalene ring of 7d with LYS721 formed two p-π bonds, which enhanced antitumor activity. Therefore, compound 7d may be developed as a potential antitumor agent.

Full text of DOI:10.1016/j.bmcl.2014.03.072

Bioorganic & Medicinal Chemistry Letters 24 (2014) 2324–2328
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and biological evaluation of compounds which contain
pyrazole, thiazole and naphthalene ring as antitumor agents
Ji-Wen Yuan , She-Feng Wang , Zhong-Liang Luo, Han-Yue Qiu, Peng-Fei Wang, Xin Zhang,
⇑
Yong-An Yang, Yong Yin, Fei Zhang, Hai-Liang Zhu
State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, 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 compounds which contain pyrazole, thiazole and naphthalene ring (1a–7a, 1b–7b, 1c–7c,
1d–7d) were firstly synthesized and their anti-proliferative activity, EGFR inhibitory activity, cytotoxicity
and inhibition to Hela cell migration were evaluated. Compound 2-(3-(3,4-dimethylphenyl)-5-(naphtha-
len-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one (7d) displayed the most potent inhibitory
Received 9 January 2014
Revised 5 March 2014
Accepted 24 March 2014
Available online 3 April 2014
activity (IC50 = 0.86 lM for Hela and IC50 = 0.12 lM for EGFR). Structure–activity relationship (SAR) anal-
ysis showed that the anti-proliferative activity was affected by A-ring-substituent (–OCH3 > –CH3 > –H >
–Br > –Cl > –F). Docking simulation of compound 7d into EGFR active site showed that naphthalene ring
Keywords:
EGFR inhibitors
Anti-tumor activity
Cell migration
Structure–activity relationship
of 7d with LYS721 formed two p–
p bonds, which enhanced antitumor activity. Therefore, compound 7d
may be developed as a potential antitumor agent.
Ó 2014 Elsevier Ltd. All rights reserved.
Pyrazole ring was a prominent skeleton motif in a lot of pharma-
ceutically active compounds, and pyrazole derivatives possess a
wide range of biological activities, such as anti-inflammatory,1 anti-
fungal,2,3 antimicrobial,4,5 anticoagulants,6 analgesic,7 antithrom-
bolic,8 anti-tumor activity,9,10 and so on. A series of pyrazoleoxime
ether derivatives were prepared and examined as cytotoxic agents,
among which 5-phenoxypyrazole exhibited very potent
cytotoxicity against XF 498 and HCT15.9 While 1-arylmethyl-3-
aryl-1H-pyrazole-5-carbohydrazide derivatives were showed
inhibitory effects on the growth of A549 cells.10
pyrazole, thiazole and naphthalene ring and evaluated their anti-
proliferative activity. As everyone knows, EGFR (epidermal growth
factor receptor) plays a very important role in cell proliferation,
survival, migration, differentiation and metastasis of many tumors.
EGFR was often used as targets for the development of novel
anticancer agents, such as Gefitinib and Elotinib.26,27 To further
understand the antitumor effect of designed compounds, docking
simulation was performed to position compound 7d into the EGFR
active site to determine the probable binding model.
The synthetic procedures of compounds 1a–7a, 1b–7b, 1c–7c
and 1d–7d were outlined in Scheme 1, Tables 1 and 2 and their
structures were confirmed by one 1H NMR and MS. The structures
of compounds 1d and 5d were demonstrated by X-ray diffraction
analysis. The crystal data were presented in Table 3, Figures 1
and 2 and have been deposited at the Cambridge Crystallographic
Data Centre as supplementary publication Nos. 987465 and
978466.
Thiazole and its derivatives were widely used in pesticides and
medicine. For example, 4-(4-chlorophenyl)-2-(3-(3,4-dimethyl-
phenyl)-5-p-tolyl-4,5-dihydro-1H-pyrazol-1-yl) thiazole displayed
the potent EGFR TK inhibitory activity and anti-proliferative activ-
ity against MCF-7,11 4-substituted methoxybenzoyl-aryl-thiazoles
exhibited anti-proliferative activity of against melanoma and pros-
tate cancer cells from l
M to nM range.12 Besides, thiazole and its
derivatives also showed other biological activities in antimicrobial,5
antifungal,13 antifilarial,14 anti-inflammatory,15 antiviral,16 and so
on. Compounds containing naphthalene ring displayed potent bio-
activity in anti-arrhythmia,17 anti-tumor18 and antioxidant.19
Due to potent biological activities and low toxicities,20,21,4,22–25
we designed and synthesized a series of compounds containing
The title compounds were evaluated for their ability to inhibit
cell proliferation against Hela, BGC823 and HepG2 cell lines using
CCK8 assay. The results in Table 4 showed good anti-proliferative
activities on Hela cancer cell line (IC50 values between 0.86 and
12.35
l
M). Among them, compound 7d showed the most potent
M.
inhibiting activity with IC50 0.86
l
SAR studies were carried out to determine how compounds
affected the anti-proliferative activity. Firstly, compound 7d
⇑
Corresponding author. Tel.: +86 25 83592572; fax: +86 25 83592672.
E-mail address: zhuhl@nju.edu.cn (H.-L. Zhu).
(IC50 = 0.86
lM) with two -CH3 in A-ring displayed stronger
anti-proliferative activity than those with one -OCH3 (5d,
These authors contributed equally to this work.
http://dx.doi.org/10.1016/j.bmcl.2014.03.072
0960-894X/Ó 2014 Elsevier Ltd. All rights reserved.

J.-W. Yuan et al. / Bioorg. Med. Chem. Lett. 24 (2014) 2324–2328
2325
O
S
N
S
N
N
N
N
N
A
A
R1
1c-7c
1d-7d
R1
R2
R2
Br
Br
O
O
O
iii
iv
S
N
NH2
O
CHO
CHO
N
S
H2N
N
H
NH2
A
A
R1
O
ii
R1
i
R2
R2
A
S
R1
NH2
O
R2
N
S
N
H2N
N
H
NH2
i
A
R1
ii
A
R2
R1
R2
O
O
O
iii
iv
Br
Br
O
S
S
N
N
N
N
N
N
A
A
R1
R1
R2
1a-7a
1b-7b
R2
Scheme 1. General synthesis compounds 1a–7a, 1b–7b, 1c–7c, 1d–7d. Reagents and conditions: (i) 40% aqueous KOH solution, ethanol, rt; (ii) thiosemicarbazide, KOH,
ethanol, reflux; (iii or iv) bromoacetic acid (or 2-bromo-1-phenylethanone), acetic anhydride, sodium acetate, acetic acid, 80 °C, 7–9 h.
Table 1
Table 2
Chemical structure of compounds 1a–7a, 1c–7c
Chemical structure of compounds 1b–7b, 1d–7d
O
S
N
S
N
N
N
N
N
A
R1
R2
A
R1
Compounds
R1
R2
Compounds
R1
R2
R2
1b
2b
3b
4b
5b
6b
7b
H
F
Cl
Br
OCH3
CH3
CH3
H
H
H
H
H
H
CH3
1d
2d
3d
4d
5d
6d
7d
H
F
Cl
Br
OCH3
CH3
CH3
H
H
H
H
H
H
CH3
Compounds
R1
R2
Compounds
R1
R2
1a
2a
3a
4a
5a
6a
7a
H
F
Cl
Br
OCH3
CH3
CH3
H
H
H
H
H
H
CH3
1c
2c
3c
4c
5c
6c
7c
H
F
Cl
Br
OCH3
CH3
CH3
H
H
H
H
H
H
CH3
same results were also found in compounds 1a–7a, 1b–7b and
1c–7c. This meant that compounds with stronger activating sub-
stituents in A-ring showed better anti-proliferative activity. The re-
sults indicated that the anti-proliferative activity was affected by
A-ring-substituent (–OCH3 > –CH3 > –H > –Br > –Cl > –F). Secondly,
IC50 = 1.48
–Br (4d, IC50 = 4.22
IC50 = 9.17
l
M), –CH3 (6d, IC50 = 1.76
l
M), –H (1d, IC50 = 3.48
l
M),
lM), –Cl (3d, IC50 = 6.32
lM) and F (2d,
l
M), the order was 5d > 6d > 1d > 4d > 3d > 2d. The

2326
Table 3
J.-W. Yuan et al. / Bioorg. Med. Chem. Lett. 24 (2014) 2324–2328
Table 4
Crystal data for compounds 1d and 5d
Inhibition (IC50) of BGC823, Hela and HepG2 cells proliferation by compounds 1a–7a,
1b–7b, 1c–7c, 1d–7d
1d
5d
Compounds
IC50(lM)
Empirical formula
Molecular weight
Crystalsize (mm3)
Temperature (K)
Radiation
Crystalsystem
Space group
a (Å)
C
22H17N3OS
C23H19N3O2S
401.2
371.1
BGC823
Hela
HepG2
0.19 ⁄ 0.23 ⁄ 0.16
0.3 ⁄ 0.35 ⁄ 0.26
1a
2a
3a
4a
5a
14.25
22.73
19.55
17.37
9.51
5.32
12.35
9.94
6.65
3.31
4.29
1.72
4.62
11.25
8.84
5.81
2.54
3.21
1.33
3.86
9.73
7.56
4.96
1.86
2.46
0.95
3.18
9.17
6.32
4.22
1.48
1.76
0.86
2.67
13.21
23.15
18.71
15.56
8.74
273(2)
273(2)
Mo-K
Monoclinc
P21/n
11.96241(8)
8.9920(6)
18.2136(13)
90.00
109.171(2)
90.00
1850.5(2)
24
1.617
0.773
912
2.46–25.72
17,883 (Rint = 0.0502)
3515
2396
3515/0/244
1.058
0.1138/0.2535
0.0790/0.2255
0.640/À0.200
a
(0.7103 Å)
Mo-Ka (0.7103 Å)
Monoclinic
P21/c
11.7565(6)
9.0469(5)
19.2557(10)
90.00
104.632(2)
90.00
1981.61(2)
26
1.636
0.782
988
2.45–25.73
18,236 (Rint = 0.0318)
3761
2869
3761/0/262
1.069
0.0955/0.2628
0.0776/0.2441
0.675/À0.450
6a
7a
13.34
8.46
10.43
7.25
b (Å)
c (Å)
1b
2b
3b
4b
5b
6b
7b
1c
2c
3c
4c
5c
11.16
19.26
16.38
14.62
8.21
10.01
7.11
9.62
17.34
14.63
12.96
7.25
8.94
6.57
10.07
19.52
16.45
13.42
7.85
a
(°)
b (°)
c
(°)
V (Å3)
Z
8.66
5.94
Dc (g cmÀ3
l
)
(mmÀ1) absort. coeff
17.19
26.53
22.14
20.31
12.56
14.73
7.37
15.73
24.12
20.43
18.22
10.36
12.69
8.49
F(000)
h rang (deg)
Reflections collected
Indep. reflns
Refns obs. [I > 2r(I)]
6c
7c
Data/restr./paras
Goodness-of-fit on F2
R1, wR2 (all data)
1d
2d
3d
4d
5d
6d
7d
Gefitinib
8.86
14.93
13.20
11.72
6.94
7.79
6.02
R1, wR2[I > 2r(I)]
Larg. peak/hole (e Å)
—
6.42
Table 5
EGFR inhibitory activity of synthetic compounds
Compounds
EGFR (IC50 lM)
1d
5b
5d
6c
6d
7a
7b
7c
6.31
5.53
2.80
5.26
3.25
3.96
1.32
0.65
0.12
0.02
7d
Gefitinib
Figure 1. Crystal structure diagram of compound 1d.
7
6
R2=0.91125
5
4
3
2
1
0
1.0
1.5
2.0
2.5
3.0
3.5
Antiproliferation activity IC50
Figure 3. Correlation between the anti-proliferation against Hela cell line and EGFR
inhibitory activity, R2 = 0.911.
Figure 2. Crystal structure diagram of compound 5d.

J.-W. Yuan et al. / Bioorg. Med. Chem. Lett. 24 (2014) 2324–2328
2327
the same trends were observed in compounds with naphthalene
ring. The anti-proliferative activities of compounds bearing
1-substituted naphthalene ring were better than those with
To further understand the potency of compound 7d and guide
SAR studies, the molecular docking of 7d and EGFR (PDB code
1M17) was performed by using the Discovery Studio 3.5. The 2D
and 3D binding model of 7d with EGFR were shown in Figures 4
and 5. In the binding model, naphthalene ring of 7d with LYS721
2-substituted, such as 1d (IC50 = 3.18
lM) > 1b (IC50 = 4.62 lM),
1c (IC50 = 3.86 M) > 1a (IC50 = 5.32 M). The results suggested
l
l
that naphthalene ring played an important role in the anti-prolifer-
ative activity. Thirdly, when 4-thiazolinone ring was substituted
with 4-phenylthiazoline, anti-proliferative activities were higher
(xd > xc, xb > xa, x = 1–7).
Ten compounds (1d, 5a–5d, 6d, 7a–7d) with better anti-prolif-
erative activities were used to test inhibitory EGFR activities. As
result in Table 5, all tested compounds exhibited good inhibitory
formed two p–p bonds, which enhanced the binding affinity,
resulting in the increased antitumor activity.
In order to evaluate cytotoxicity of the potent anti-tumor
agents, we determined cytotoxicity data (CC50) of the ten com-
pounds against human macrophage by the CCK-8 assay. As shown
in Table 6, no cytotoxicity was observed. Metastases are the dis-
semination of cancer cells from the primary tumor to a distant or-
gan. Studies showed that more than 90% of cancer patients die
from tumor metastasis, so inhibiting cancer cell migration was
an effective way for curing cancer.28 We analyzed the relationship
between 7d’s concentration with Hela cell survival ratios by CCK8
assay to test inhibition of cell migration. The result showed that 7d
EGFR activities with IC50 between 0.12 and 6.31
compound 7d showed highest inhibitory EGFR activity
(IC50 = 0.12 M). SAR analysis of ten compounds showed
lM. Among,
l
a
moderate correlation between anti-proliferation and EGFR inhibi-
tory, as showed in Figure 3, with R2 value was 0.911.
Figure 4. 2D molecular docking of compound 7d with 1M17.
Figure 5. 3D model of the interaction between compound 7d and 1M17 bonding site.

2328
J.-W. Yuan et al. / Bioorg. Med. Chem. Lett. 24 (2014) 2324–2328
Table 6
Acknowledgments
The median cytotoxic concentration (CC50) data of tested compounds
a
a
Compounds
CC50
(lMa)
Compounds
CC50
(
lMa)
This work was supported by Major Projects on Control and Rec-
tification of Water Body Pollution (2011ZX07204-001-004), and by
Henan Educational Committee (14B150036).
1d
5c
6c
7a
7c
Gefitinib
345.3
284.8
289.6
342.2
382.4
280.6
5b
5d
6d
7b
7d
273.4
363.2
396.1
382.7
397.3
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2014.03.
072.
a
Minimum cytotoxic concentration required to cause a microscopically detect-
able alteration of normal cell morphology.
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