Structure-Activity Relationship of 4,6-Disubstituted Pyrimidines as EGFR and VEGFR-2 Tyrosine Kinase Inhibitors

Full text of DOI:10.1002/bkcs.11278

Communication
DOI: 10.1002/bkcs.11278
BULLETIN OF THE
J. Song et al.
KOREAN CHEMICAL SOCIETY
Structure-Activity Relationship of 4,6-Disubstituted Pyrimidines as
EGFR and VEGFR-2 Tyrosine Kinase Inhibitors
*
Jiho Song, Jung Wook Lee, Shin Hyuck Chung, Michelle A. Wenas, and Kyung Hoon Min
College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
*E-mail: khmin@cau.ac.kr
Received August 4, 2017, Accepted August 18, 2017
Keywords: EGFR, VEGFR-2, Tyrosine kinase inhibitors, Pyrimidine
Dysregulation of the epidermal growth factor receptor
disubstituted pyrimidines against EGFR and VEGFR-2.
Herein, we describe the synthesis of 4,6-disubstituted
pyrimidines and their inhibitory effects on EGFR and
VEGFR-2 to investigate SAR.
The synthetic procedures for compounds 2a–d, 4a–g,
and 6 are outlined in Schemes 1 and 2.
4,6-Dianilinopyrimidine derivatives 2a–b and 4-anilino-
6-phenoxy derivatives 2c–d were prepared by two step
sequence from 4,6-dichloropyrimidine (Scheme 1). Com-
(
EGFR) signaling pathway by overexpression and1
persistent-activation has been observed in various cancers.
During tumor growth, angiogenesis is essential for supply-
ing nutrients and oxygen. Vascular endothelial growth fac-
2
tor receptor-2 (VEGFR-2) is the predominant mediator of
3
tumor angiogenesis among many angiogenic factors. For
these reasons, EGFR and VEGFR-2 have been intensively
explored as attractive molecular targets for anti-cancer ther-
apy, and several tyrosine kinase inhibitors (TKIs) and
monoclonal antibodies targeting EGFR or VEGFR-2 have
pounds 1a–d were synthesized through the S Ar reaction
N
of 4,6-dichloropyrimidine with anilines or phenols. Subse-
quent addition of 4-morpholinoanilines to the 6-position of
pyrimidine at high temperature using a microwave reactor
yielded 2a–d. 4-Anilino-6-(5-indolyloxy)-pyrimidine deriv-
atives 4a–g and 6 were synthesized through a similar
method to the one used for preparation of 2c–d.
All synthesized compounds were tested for inhibitory
effects on EGFR and VEGFR kinase activities through the
Eurofins kinase profiling service (Table 1).
Introduction of a benzimidazole instead of an indole moi-
ety (2b) led to almost loss of activity against EGFR and
VEGFR-2. Replacement of indole with 4-bromo-2-
fluorobenzene and 3-ethynylbenzene (2c–d) also decreased
the potency against both EGFR and VEGFR-2. Compared
to that of MKP 123, N-methylated indole 6 displayed
1,2
been marketed.
Cross-talk between the EGFR and VEGFR-2 signaling
pathways can cause resistance to inhibitors of each signal-
4
–6
ing pathway. Combination of bevacizumab (anti-VEGF-
A) and erlotinib (EGFR TKI) has substantially increased
progression-free survival of non-small cell lung cancer
patients with EGFR-activating mutations compared to that
7
achieved with erlotinib alone. In addition, VEGFR contrib-
8
utes to the resistance to EGFR inhibitors in cancer cells.
Concurrent inhibition of EGFR and VEGFR signaling
could prevent or impede resistance to EGFR TKIs, includ-
9
ing that in patients with the EGFR T790M mutation. Thus,
a proper strategy for combined inhibition of EGFR and
VEGFR-2 could be an effective approach for cancer
treatment.
We have previously reported the structure-activity rela-
tionship (SAR) of indole tethered pyrimidines, which are
able to concurrently inhibit angiokinases including EGFR
10
and VEGFR-2. Based on the previously reported MKP
compounds (Figure 1), we further explored SAR of 4,6-
Scheme 1. Reagents and conditions: (a) anilines or phenols, DBU,
MeCN, RT, 12 h; (b) 4-morpholinoanilines, 1-BuOH, microwave,
200 C, approximately 0.5–1 h.
1
0
ꢀ
Figure 1. Structure of MKP compounds.
Bull. Korean Chem. Soc. 2017
© 2017 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Communication
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BULLETIN OF THE
KOREAN CHEMICAL SOCIETY
activity for EGFR. This result suggested that the chain
length could largely affect the inhibitory effect on EGFR
kinase. The potency of 4e, an N-methyl piperazine analog
of MKP121 slightly decreased against both EGFR and
VEGFR-2 compared to those of the parent compound.
A morpholine derivative of MKP123, 4f displayed a
decreased activity for EGFR, but retained its activity for
VEGFR-2. A regioisomer of MKP121, 4 g showed more
potent activities than those of MKP121 for both kinases.
In summary, we have described the synthesis and biolog-
ical evaluation of 4,6-disubstitutedpyrimidines as dual
kinase inhibitors of EGFR and VEGFR-2 for extending
SAR of indole substituted pyrimidines. In this scaffold, 5-
indolyloxy moiety was important to show dual kinase activ-
ity. Regarding aniline moiety, various substituents were tol-
erable, but position and size of them affected activities and
kinase selectivity. Further investigation is required to clar-
ify the SAR of aniline moiety in detail.
Scheme 2. Reagents and conditions: (a) 5-hydroxyindole, DBU,
MeCN, RT, 12 h; (b) anilines, 1-BuOH, microwave, 200 C,
ꢀ
approximately 0.5–1 h; (c) CH
3
I, K
2
CO
3
, DMF, RT; (d) 5-amino-
1-BuOH, microwave,
2
2
-methyl
00 C, 0.5 h.
benzenesulfonamide,
Acknowledgments. This research was supported by the
National Research Foundation of Korea (NRF) Grant
funded by the Korean Government (NRF-2015R1A5A100
ꢀ
8
958) and by the Chung-Ang University Research Grants
Table 1. Kinase activity of 4,6-disubstituted pyrimidines for
EGFR and VEGFR-2.
in 2015.
%
inhibition at 1 μM
IC50 (nM)
EGFR
VEGFR-2
EGFR
VEGFR-2
References
MKP 118
MKP 120
MKP 121
MKP 123
100
99
95
98
98
26
84
99
99
97
95
2
22
89
96
95
98
1
38
91
92
90
90
92
98
95
95
64
7
10
31
18
26
ND
155
138
63
26
27
1200
22
30
1. C. Yewale, D. Baradia, I. Vhora, S. Patil, A. Misra, Biomate-
rials 2013, 34, 8690.
2
. N. Ferrara, A. P. Adamis, Nat. Rev. Drug Discov. 2016,
5, 385.
45
1
2
2
2
2
4
4
4
4
4
4
4
6
a
b
c
d
a
b
c
d
e
f
357
ND
155
>3000
74
46
57
90
46
37
22
1345
3
4
. H. L. Goel, A. M. Mercurio, Nat. Rev. Cancer 2013, 13, 871.
. A. Garofalo, L. Goossens, A. Lemoine, S. Ravez, P. Six,
M. Howsam, A. Farce, P. Depreux, Med. Chem. Commun.
2
011, 2, 65.
5
. A. Bozec, A. Sudaka, J. L. Fischel, M. C. Brunstein,
M. C. Etienne-Grimaldi, G. Milano, Br. J. Cancer 2008,
9
9, 93.
ND
58
305
16
6. N. Schicher, V. Paulitschke, A. Swoboda, R. Kunstfeld,
R. Loewe, P. Pilarski, H. Pehamberger, C. Hoeller, Clin. Can-
cer Res. 2009, 15, 3495.
95
81
96
48
7
. T. Seto, T. Kato, M. Nishio, K. Goto, S. Atagi, Y. Hosomi,
N. Yamamoto, T. Hida, M. Maemondo, K. Nakagawa,
S. Nagase, I. Okamoto, T. Yamanaka, K. Tajima, R. Harada,
M. Fukuoka, N. Yamamoto, Lancet Oncol. 2014, 15, 1236.
. L. Huang, L. Fu, Acta Pharm. Sin. B 2015, 5, 390.
. G. N. Naumov, M. B. Nilsson, T. Cascone, A. Briggs,
O. Straume, L. A. Akslen, E. Lifshits, L. A. Byers, L. Xu,
H. Wu, P. Jänne, S. Kobayashi, B. Halmos, D. Tenen,
X. M. Tang, J. Engelman, B. Yeap, J. Folkman,
B. E. Johnson, J. V. Heymach, Clin. Cancer Res. 2009,
g
830
ND, not determined.
8
9
strongly reduced inhibitory effect on both EGFR and
VEGFR-2, indicating that the NH group of the indole ring
is essential for the binding affinity of compounds to EGFR
and VEGFR-2. It is assumed that the 5-hydroxyindole moi-
ety is crucial for the ability of 4,6-disubstituted pyrimidines
to bind to both EGFR and VEGFR-2.
1
5, 3484.
1
0. J. Song, J. Yoo, A. Kwon, D. Kim, H. K. Nguyen, B. Y. Lee,
W. Suh, K. H. Min, PLoS One 2015, 10, e0138823. DOI:
https://doi.org/10.1371/journal.pone.0138823.
Alkylether derivatives 4a–d retained inhibitory effects on
both targets except 4d with a long side chain, which lost its
Bull. Korean Chem. Soc. 2017
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