Design, synthesis and activity of novel sorafenib analogues bearing chalcone unit

Article abstract of DOI:10.1016/j.bmcl.2016.10.029

Two series of sorafenib derivatives (N-methylpicolinamide-4-oxy) chalcones (5a–o, 7a–e) were synthesized and characterized by NMR and MS. All of the target compounds were evaluated for the cytotoxicity against A549, HepG2, MCF-7, and PC-3 cancer cell lines and some selected compounds were further evaluated for the activity against VEGFR-2/KDR and BRAF kinases. The results indicated that all the compounds showed moderate to good antitumor activity, and the compound 5c showed well cytotoxic activity against HepG2, MCF-7 and PC-3 cell lines with IC₅₀values of 0.56?±?0.83?μM, 3.88?±?1.03?μM and 3.15?±?0.81?μM, which were 1.03–6.14-fold more active than sorafenib (3.44?±?1.50?μM, 3.18?±?1.43?μM, 3.24?±?0.45?μM), respectively. The compound 5b showed good activity on VEGFR-2/KDR kinase, and its IC₅₀value was 0.72?μM. Structure–activity relationships (SARs) and docking studies indicated that replacement of urea group of sorafenib by chalcone ketones improved the cytotoxic activity, and the results suggested that halogen [3-Br, 4-F] and methoxy (substituted on C-3,4,5 or C-2,3,4 position) substitution was benefit for the activity.

Full text of DOI:10.1016/j.bmcl.2016.10.029

Bioorganic & Medicinal Chemistry Letters xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Design, synthesis and activity of novel sorafenib analogues bearing
chalcone unit
⇑
Min Wang, Shan Xu , Chunjiang Wu, Xiaobo Liu, Hong Tao, Yanli Huang, Yongchan Liu, Pengwu Zheng,
Wufu Zhu
⇑
School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Two series of sorafenib derivatives (N-methylpicolinamide-4-oxy) chalcones (5a–o, 7a–e) were synthe-
sized and characterized by NMR and MS. All of the target compounds were evaluated for the cytotoxicity
against A549, HepG2, MCF-7, and PC-3 cancer cell lines and some selected compounds were further
evaluated for the activity against VEGFR-2/KDR and BRAF kinases. The results indicated that all the
compounds showed moderate to good antitumor activity, and the compound 5c showed well cytotoxic
Received 6 September 2016
Revised 6 October 2016
Accepted 11 October 2016
Available online xxxx
activity against HepG2, MCF-7 and PC-3 cell lines with IC50 values of 0.56 0.83
and 3.15 0.81 M, which were 1.03–6.14-fold more active than sorafenib (3.44 1.50
3.18 1.43 M, 3.24 0.45 M), respectively. The compound 5b showed good activity on VEGFR-2/KDR
kinase, and its IC50 value was 0.72 M. Structure–activity relationships (SARs) and docking studies
indicated that replacement of urea group of sorafenib by chalcone ketones improved the cytotoxic
activity, and the results suggested that halogen [3-Br, 4-F] and methoxy (substituted on C-3,4,5 or C-
2,3,4 position) substitution was benefit for the activity.
lM, 3.88 1.03 lM
Keywords:
Sorafenib derivatives
(N-Methylpicolinamide-4-oxy) chalcones
VEGFR-2/KDR kinase inhibitors
Anticancer activity
l
lM,
l
l
l
Ó 2016 Elsevier Ltd. All rights reserved.
Introduction
anti-inflammatory, antitumor, antitubercular, and so on.16 Many
chalcone derivatives were reported, such as compound I, II (the
Cancer is a very complex disease which affects different organs
and systems of the body.1,2 And cancer therapy is an extremely
challenging field for medicinal chemists.3 We know that angiogen-
esis is one of the critical processes that affect growth and develop-
ment of cancerous cells.4 It is the key factor in the advancement of
various human diseases, including cancer, where it is essential for
the growth, spread and survival of tumors.5 Accordingly, inhibition
of tumour angiogenesis has become a validated approach for the
treatment of cancer. Angiogenesis is a complex process regulated
by multiple growth factors and cytokines.6 Among these factors,
vascular endothelial growth factor receptor-2 (VEGFR-2/KDR) is
one of the most potent angiogenic factors involved in tumor
growth.7 So far, nine drugs [sorafenib,8 sunitinib,9 pazopanib,4 axi-
tinib,10 vandetanib,11 regorafenib,12 lenvatinib,13 nintedanib
(BIBF1120)14 and cediranib (AZD2171)15] targeting VEGFR-2/KDR
have been approved for the treatment of cancers.
structures were shown in Fig. 1),17,18 and these compounds elicited
strong cytotoxic activity. The results showed that the chalcone
scaffold played a key role to the activity. Inspired by this, we
replaced diarylurea moiety of sorafenib with chalcone moiety in
this study, expecting to screen sorafenib derivatives with excellent
in vitro/in vivo activity as VEGFR-2/KDR inhibitors. As a result, two
series of novel sorafenib derivatives bearing chalcones unit (5a–o
and 7a–e) were designed and synthesized. The structures of target
compounds are shown in Figure 1. In this paper, we report the
design, synthesis, and structure–activity relationships (SAR) of sor-
afenib derivatives of (N-methylpicolinamide-4-oxy) chalcones.
The target compounds 5a–o and 7a–e were prepared as
illustrated in Scheme 1. Firstly, compounds
2 and 3 were
synthesized according to the reported procedures.19 Then the key
compound 4-(4-acetylphenoxy)-N-methylpicolinamide (4) was
prepared by 1-(4-hydroxyphenyl) ethanone, 4-chloro-N-methylpi-
colinamide (3) and K2CO3 in DMSO, which was refluxed for
about 5 h in three neck flask. The other intermediate
4-(4-formylphenoxy)-N-methylpicolinamide (6) was achieved
from 4-chloro-N-methylpicolinamide (3) via substitution reaction
with 4-hydroxybenzaldehyde and potassium tert-butoxide.
4-(4-Acetylphenoxy)-N-methylpicolinamide (4) [intermediate
In recent years, novel chalcones were synthesized due to their
various biological activities, such as antimalarial, antileishmanial,
⇑
Corresponding authors. Tel./fax: +86 791 83802393.
E-mail addresses: shanxu9891@126.com (S. Xu), zhuwf@jxstnu.edu.cn,
zhuwufu-1122@163.com (W. Zhu).
http://dx.doi.org/10.1016/j.bmcl.2016.10.029
0960-894X/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Wang, M.; et al. Bioorg. Med. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.bmcl.2016.10.029

2
M. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2016) xxx–xxx
urea group
y
x
o
n
O
e
H
N
H
N
h
p
p
u
CF3
Cl
o
r
O
O
g
O
O
R
O
H
N
N
Chalcone
Cl
N
O
I
Sorafenib
O
O
7a-e
5a-o
A
Ar
O
H3CO
O
Ar
O
N
OH
H
N
R
II
O
Target compounds
Figure 1. Structures of small-molecule antitumor agents and target compounds (5a–o, 7a–e).
O
O
CH3
Ar
O
N
O
N
H
N
H
N
c
d
Cl
N
Cl
N
O
O
5a-o
4
D
E
H
N
O
O
N
COOH
COCl
H
Ar
O
e
1
2
3
f
O
N
O
N
H
N
H
N
7a-e
O
6
O
Scheme 1. Reagents and conditions: (a) SOCl2, NaBr, chlorobenzene, 85 °C, 20 h, 85%; (b) 30% MeNH2, toluene, 20 °C, 6 h,70%; (c) K2CO3, DMSO, reflux, 5 h, 32%; (d) KOH,
methanol, rt 6 h. 65.2–81.7%; (e) tert-BuOK, DMF, reflux, 15 h, 30%; (f) NaH, THF, rt 8 h. 35.1–55.3%.
4-(4-formylphenoxy)-N-methylpicolinamide (6)] was reacted with
substituted benzaldehyde (substituted acetophenone) through
aldol condensation to get the target compound 5a–o (7a–e).
The target compounds were evaluated for their VEGFR-2/KDR,
B-Raf kinase activities and cytotoxicity activities in vitro20,21
against four cancer cell lines including the HepG2, A549, MCF-7
and PC-3. As illustrated in Table 1, twelve of the synthesized com-
pounds showed moderate to excellent cytotoxicity activity against
the different cancer cells. And three of them (5b, 5c, 5i) showed
excellent inhibitory activity on VEGFR-2/KDR and B-Raf kinase
HepG2 cancer cell line. The compound 7b was 1.55 times more
active than sorafenib (IC50 values: 2.05 0.42 vs
3.18 1.43 M) against MCF-7 cancer cell line.
l
M
l
In general, the second series of the target compounds (7a–e)
were less active than the first series (5a–o) against the four tested
cancer cell lines. The cytotoxicity activity of the target compounds
against MCF-7, PC-3, HepG2 cancer cell lines were better while it
was worse against A549 cell line, which suggested that the intro-
duction of chalcone framework maintained or promoted the cyto-
toxicity activity compared with sorafenib against PC-3, MCF-7 or
HepG2 cell lines. Furthermore, Variations in substitutions of the
aryl moiety had a significant impact on the activity. It was indi-
cated that halogen [3-Br (5b), 4-F (7b)] and methoxy (substituted
on C-3,4,5 or C-2,3,4 position) substitution were benefit for the
activity. For the first series, it’s seem to be that electron withdraw-
ing groups such as halogen atoms (-Br) at C-3 position and
electron-donating group such as methoxy at C-3,4,5 or C-2,3,4
position were advantageous to the compounds’ activity, and that
was why compounds 5b (3-Br), 5c (3,4,5-TriOCH3), 5m
with the IC50 value of VEGFR-2/KDR: 0.72
lM, 3.2 lM, 1.1 lM
and B-Raf: 2.9 M, 1.8 M, 2.4 M in Table 2, respectively. Docking
l
l
l
analysis of compounds with VEGFR-2/KDR and B-Raf was per-
formed using compound 5b and 5c.
As shown in Table 1, nine of the target compounds (5a, 5b, 5c,
5d, 5e, 5i, 5m, 7b and 7c) were equivalent or even higher potency
than sorafenib against one or more cancer cell lines. Especially
compound 5c (IC50: 0.56 0.83
than lead compound sorafenib (IC50
l
M) was 6.14-fold more active
3.44 1.50 M) against
:
l
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M. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2016) xxx–xxx
3
Table 1
Structures and activity of target compounds 5a–o and 7a–e
a
Compd. No.
Ar
IC50 (lM)
A549
HepG2
MCF-7
PC-3
Cl
5a
5b
5c
5d
5e
9.46 1.27
11.68 2.52
3.99 1.01
9.22 1.56
Cl
9.94 0.98
9.50 1.26
26.43 1.40
21.11 2.00
2.87 1.52
0.56 0.83
5.43 1.61
7.32 1.65
10.37 1.66
3.88 1.03
9.52 1.04
21.13 1.55
3.40 0.99
3.15 0.81
3.87 1.06
4.76 1.13
Br
OCH3
OCH3
OCH3
CN
F
Cl
NO2
5f
NAc
NDd
ND
11.06 1.07
ND
5g
5h
5i
ND
NA
NA
NO2
OCH3
NA
ND
ND
NA
5.04 0.96
6.64 1.19
5.96 1.08
3.17 0.32
Cl
5j
33.69 2.68
18.58 1.08
NA
11.43 1.34
12.59 1.38
NA
13.23 1.04
28.49 1.26
NA
8.26 0.34
6.14 1.00
18.46 0.76
Cl
F
5k
5l
Br
OCH3
OCH3
5m
5n
ND
NA
9.81 1.27
2.91 1.08
ND
NA
OCH3
NA
ND
Cl
Cl
O
5o
7a
ND
ND
ND
ND
ND
ND
NO2
F
41.42 1.80
54.31 2.07
7b
7c
7d
ND
12.35 0.76
22.00 1.94
36.56 1.80
2.05 0.42
7.10 0.62
17.52 0.95
ND
Br
20.13 0.91
ND
3.56 0.43
ND
Cl
7e
ND
NA
24.88 0.45
3.18 1.43
ND
Sorafenibb
—
2.92 0.68
3.44 1.50
3.24 0.45
Bold values means the IC50 values less or equal than 10 lM.
a
The values are an average of two separate determinations.
Used as positive controls.
b
c
NA: not active (IC50 > 50
Not determined.
lM).
d
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4
M. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2016) xxx–xxx
Table 2
Though Figure 2, the phenomenon of dose-dependent was
observed of representative compounds 5b. In other words, the
activity of this series of compounds was dose-dependent.
Activity against VEGFR-2/KDR and BRAF kinases of four compounds
Compd. No.
IC50 (l
M)a
To explore the binding modes of target compounds with
VEGFR-2/KDR (Fig. 3a) (PDB ID code:4ASD22) and B-Raf (Fig. 3b)
(PDB ID code:2FB823), molecular docking simulation studies were
carried out by using SURFLEX-DOCK module of SYBYL 6.9.1 pack-
age version. Based on the in vitro inhibition results, we selected
compound 5b and 5c in this study, as ligand example, and the
structures of VEGFR-2/KDR and B-Raf were selected as the docking
model.
VEGFR-2/KDR
BRAF
5b
5c
5i
7b
Sorafenib
0.72
3.2
2.9
1.8
2.4
NA
1.1
NAc
b
0.17 0.09
0.072 0.002
0.31 0.62
b
Staurosporine
NDd
a
b
c
The values are an average of two separate determinations.
Used as positive controls.
The binding modes of compound 5b, 5c and lead compound are
shown in Figure 3. As depicted in Figure 3a, compound 5b and
sorafenib mostly overlap in the binding model and amide group
formed one hydrogen bond with residues CYS919. In Figure 3b,
we can see compound 5c formed four hydrogen bonds with residue
ASP594, SER536. Analysis of compound 5b and 5c’s binding
mode in the active binding site demonstrated that the docking
mode of the 5b was similar to the lead compound sorafenib and
the two hydrogen bonds play an important role in the increase of
the inhibitory potency of sorafenib derivatives bearing
(N-methylpicolinamide-4-oxy) chalcones against VEGFR-2/KDR
inhibitor according to the docking results and the cytotoxicity
activity. Furthermore, the docking results also give us a new
direction to design new VEGFR-2/KDR and B-Raf inhibitors.
In summary, we designed and synthesized two series
sorafenib derivatives of (N-methylpicolinamide-4-oxy) chalcones
(5a–o, 7a–e). VEGFR-2/KDR and B-Raf kinases and four human can-
cer cell lines (HepG2, A549, MCF-7, and PC-3) were used to evaluate
the target compounds. Twelve of the synthesized compounds
showed moderate to excellent cytotoxicity activity against the
NA: not active (IC50 > 50
Not determined.
lM).
d
(2,3,4-TriOCH3) were more active than other compounds. But the
compound 5i was an exception, it exhibit better activity against
PC-3 cell line with IC50 value 3.17 0.32
more activity than sorafenib (IC50: 3.24 0.45
series, the compound substituted with 4-F was beneficial to the
activity (7b against MCF-7), and it was more active than sorafenib.
The inhibitory activity on VEGFR-2/KDR and B-Raf kinases of
four compounds (5b, 5c, 5i, 7b) were listed in the Table 2. Three
of them (5b, 5c, 5i) showed excellent inhibitory activity on
VEGFR-2/KDR and B-Raf kinase with the IC50 value of VEGFR-2:
l
M, which was 1.02-fold
l
M). For the second
0.72 lM, 3.2 lM, 1.1 lM and B-Raf: 2.9 lM, 1.8 lM, 2.4 lM,
respectively. The activity toward VEGFR-2/KDR kinase of com-
pound 5b is equal to the reference compound sorafenib. The result
shown that these series of compounds were potent selective
VEGFR-2/KDR inhibitors. However, exact action mechanism is not
quite clear right now.
tested cancer cells, whose potency from single-digit
lM to
nanomolar range. And nine of them (compounds 5a, 5b, 5c, 5d,
5e, 5i, 5m, 7b and 7c) were equivalent or even higher potency than
sorafenib against one or more cancer cell lines. The compound 5c
(VEGFR-2/KDR IC50: 3.2
toxic activity against HepG2, MCF-7 and PC-3 cell lines with IC50
values of 0.56 0.83 M, 3.88 1.03 M and 3.15 0.81 M, which
were 1.03 to 6.14-fold more active than sorafenib (3.44 1.50 M,
3.18 1.43 M, 3.24 0.45 M), respectively. The compound 5b
(VEGFR-2/KDR IC50 0.72 M) showed good activity on
lM, B-Raf IC50: 1.9 lM) showed well cyto-
l
l
l
l
l
l
:
l
VEGFR-2/KDR kinase. The analysis of SARs indicated that electron
withdrawing groups such as halogen [3-Br (5b), 4-F (7b)] and
electron-donating group such as methoxy (substituted on C-3,4,5
or C-2,3,4 position) substitution was benefit for the activity.
Acknowledgments
This work was supported by The National Natural Science
Funds (Nos. 81460527, 21662014), Natural Science Foundation
Figure 2. Relationship between activity and concentration of selected compounds
5c against four cancer cell lines.
Figure 3. (a, b) Binding models of compound 5b (shown in orange sticks), 5c (shown in green sticks) and lead compound (shown in cyan sticks) with VEGFR-2/KDR (a) and B-
Raf (b), respectively. H-bonding interactions between the 5b or 5c, lead compound and VEGFR-2/KDR, B-Raf are denoted by dashed lines in yellow.
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M. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2016) xxx–xxx
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