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2-Arylquinolines as novel anticancer agents with dual EGFR/FAK kinase inhibitory activity: synthesis, biological evaluation, and molecular modelling insights

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  • Faculty of Pharmacy, Kafrelsheikh University, Egypt

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In this study, different assortments of 2-arylquinolines and 2,6-diarylquinolines have been developed. Recently, we have developed a new series of 6,7-dimethoxy-4-alkoxy-2-arylquinolines as Topoisomerase I (TOP1) inhibitors with potent anticancer activity. Utilising the SAR outputs from this study, we tried to enhance anticancer and TOP1 inhibitory activities. Though target quinolines demonstrated potent antiproliferative effect, specifically against colorectal cancer DLD-1 and HCT-116, they showed weak TOP1 inhibition which may be attributable to their non-coplanarity. Thereafter, screening against kinase panel revealed their dual inhibitory activity against EGFR and FAK. Quinolines 6f, 6h, 6i, and 20f were the most potent EGFR inhibitors (IC50s = 25.39, 20.15, 22.36, and 24.81 nM, respectively). Meanwhile, quinolines 6f, 6h, 6i, 16d, and 20f exerted the best FAK inhibition (IC50s = 22.68, 14.25, 18.36, 17.36, and 15.36 nM, respectively). Finally, molecular modelling was employed to justify the promising EGFR/FAK inhibition. The study outcomes afforded the first reported quinolines with potent EGFR/FAK dual inhibition.
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2-Arylquinolines as novel anticancer agents with
dual EGFR/FAK kinase inhibitory activity: synthesis,
biological evaluation, and molecular modelling
insights
Mostafa M. Elbadawi, Wagdy M. Eldehna, Amer Ali Abd El-Hafeez, Warda R.
Somaa, Amgad Albohy, Sara T. Al-Rashood, Keli K. Agama, Eslam B. Elkaeed,
Pradipta Ghosh, Yves Pommier & Manabu Abe
To cite this article: Mostafa M. Elbadawi, Wagdy M. Eldehna, Amer Ali Abd El-Hafeez, Warda
R. Somaa, Amgad Albohy, Sara T. Al-Rashood, Keli K. Agama, Eslam B. Elkaeed, Pradipta
Ghosh, Yves Pommier & Manabu Abe (2022) 2-Arylquinolines as novel anticancer agents
with dual EGFR/FAK kinase inhibitory activity: synthesis, biological evaluation, and molecular
modelling insights, Journal of Enzyme Inhibition and Medicinal Chemistry, 37:1, 349-372, DOI:
10.1080/14756366.2021.2015344
To link to this article: https://doi.org/10.1080/14756366.2021.2015344
© 2021 The Author(s). Published by Informa
UK Limited, trading as Taylor & Francis
Group.
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RESEARCH PAPER
2-Arylquinolines as novel anticancer agents with dual EGFR/FAK kinase inhibitory
activity: synthesis, biological evaluation, and molecular modelling insights
Mostafa M. Elbadawi
a,b
, Wagdy M. Eldehna
b
, Amer Ali Abd El-Hafeez
c,d
, Warda R. Somaa
e
, Amgad Albohy
f
,
Sara T. Al-Rashood
g
, Keli K. Agama
h
, Eslam B. Elkaeed
i
, Pradipta Ghosh
d,j,k,l
, Yves Pommier
h
and Manabu Abe
a
a
Department of Chemistry, Graduate School of Science, Hiroshima University, Hiroshima, Japan;
b
Department of Pharmaceutical Chemistry,
Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, Egypt;
c
Pharmacology and Experimental Oncology Unit, Cancer Biology Department,
National Cancer Institute, Cairo University, Cairo, Egypt;
d
Department of Cellular and Molecular Medicine, University of California San Diego, La
Jolla, CA, USA;
e
Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, Egypt;
f
Department of Pharmaceutical Chemistry, Faculty of
Pharmacy, The British University in Egypt (BUE), Cairo, Egypt;
g
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud
University, Riyadh, Saudi Arabia;
h
Developmental Therapeutics Branch, Laboratory of Molecular Pharmacology, Center for Cancer Research,
National Cancer Institute, NIH, Bethesda, MD, USA;
i
Department of Pharmaceutical Sciences, College of Pharmacy, AlMaarefa University, Riyadh,
Saudi Arabia;
j
Department of Medicine, University of California San Diego, La Jolla, CA, USA;
k
Moores Comprehensive Cancer Center, University
of California San Diego, La Jolla, CA, USA;
l
Veterans Affairs Medical Center, La Jolla, CA, USA
ABSTRACT
In this study, different assortments of 2-arylquinolines and 2,6-diarylquinolines have been developed.
Recently, we have developed a new series of 6,7-dimethoxy-4-alkoxy-2-arylquinolines as Topoisomerase I
(TOP1) inhibitors with potent anticancer activity. Utilising the SAR outputs from this study, we tried to
enhance anticancer and TOP1 inhibitory activities. Though target quinolines demonstrated potent antipro-
liferative effect, specifically against colorectal cancer DLD-1 and HCT-116, they showed weak TOP1 inhib-
ition which may be attributable to their non-coplanarity. Thereafter, screening against kinase panel
revealed their dual inhibitory activity against EGFR and FAK. Quinolines 6f,6h,6i, and 20f were the most
potent EGFR inhibitors (IC
50
s¼25.39, 20.15, 22.36, and 24.81nM, respectively). Meanwhile, quinolines 6f,
6h,6i,16d,and20f exerted the best FAK inhibition (IC
50
s¼22.68, 14.25, 18.36, 17.36, and 15.36nM,
respectively). Finally, molecular modelling was employed to justify the promising EGFR/FAK inhibition. The
study outcomes afforded the first reported quinolines with potent EGFR/FAK dual inhibition.
GRAPHICAL ABSTRACT
ARTICLE HISTORY
Received 12 November 2021
Revised 29 November 2021
Accepted 1 December 2021
KEYWORDS
Quinoline; anticancer; EGFR
inhibitors; FAK inhibitors;
molecular dynamics
CONTACT Mostafa M. Elbadawi mostafa_elbadawi@pharm.kfs.edu.eg Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1
Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan; Wagdy M. Eldehna wagdy2000@gmail.com Department of Pharmaceutical Chemistry, Faculty of
Pharmacy, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt; Manabu Abe mabe@hiroshima-u.ac.jp Department of Chemistry, Graduate School of Science,
Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
Supplemental data for this article can be accessed here.
ß2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY
2022, VOL. 37, NO. 1, 349372
https://doi.org/10.1080/14756366.2021.2015344
1. Introduction
Cancer is a major health obstacle in the world threating the life of
millions of people annually
1,2
. The universal burden of cancer has
been expected to rise to 21.6 million in 2023 compared to 14.1
million in 2012 and was predicted to increase to 28.4 million in
2040 with 47% increment relative to 2020
35
. In 2020, 19.3 million
new cancer cases have been diagnosed and 10 million cancer
patients passed away. As established by WHO in 2019, cancer was
estimated to be the first or second dominant cause of death for
the ages <70 years in 112 countries, while it was projected to be
the third or fourth death cause in 23 countries. In general, the
incidence and mortality of cancer are growing rapidly world-
wide
4,6
. Subsequently, enormous attempts have been imple-
mented to develop potent anticancer drugs through
investigations of diverse scaffolds against numerous potential che-
motherapeutic targets
79
.
Epidermal growth factor receptor (EGFR) is a member of tyro-
sine kinase family in which the endogenous ligand binds to the
extracellular domain leading to conformational changes and
dimerisation of EGFR resulting in its activation which subsequently
stimulates its intrinsic intracellular protein-tyrosine kinase activ-
ity
10
. EGFR is over-expressed in many solid tumours and is related
to cancer cell proliferation, angiogenesis and metastasis, so it has
a critical role in cancer growth. Therefore, EGFR has been vali-
dated as an efficient target for anticancer drug discovery. In the
last two decades, different 4-anilinoquinazoline-based EFGR inhibi-
tors, such as Gefitinib, Erlotinib, Afatinib, and Dacomitinib
(Figure 1), have been FDA-approved for clinical use in treatment
of non-small cell lung cancer
11,12
.
Focal adhesion kinase (FAK) is a cytoplasmic non-receptor tyro-
sine kinase involved in signal transductions from cell adhesions to
regulate different biological cell functions including survival and
cell migration
13,14
. Also, it is activated and overexpressed in
diverse cancer types controlling cancer proliferation, survival and
metastasis. Thus, FAK has been identified as a promising drug-
gable target for targeted cancer therapy. Currently, several FAK
inhibitors, such as 2,4-diaminopyridine derivative GSK2256098 and
2,4-diaminopyrimidine derivative Defactinib (Figure 1), are cur-
rently being evaluated in clinical trials for cancer treatment, in
addition to the 2,4-diaminopyrimidine derivative TAE-226 (Figure
1) which displayed potent antitumor impact in different cancer
types in vivo and in vitro and usually used as a reference
drug
7,15,16
. Noteworthy, it was established that the most affected
colorectal cancer expressed high levels of EGFR and FAK that par-
ticularly correlated with tumour angiogenesis, cancer aggressive-
ness and poor prognosis
17,18
.
Thus, dual EGFR/FAK inhibition mechanism is an efficient strat-
egy to fight cancer that could be attributed to a non-overlapping
downstream signalling/inhibition
19,20
. For example, the kinase
inhibitor APG-2449 (Figure 1) was reported to improve the antitu-
mor effect of Ibrutinib via EGFR/FAK inhibition mechanism in
Figure 1. Some reported EGFR and FAK inhibitors.
350 M. M. ELBADAWI ET AL.
oesophageal squamous cell carcinoma
19
. Also, combined EGFR/
FAK inhibition caused higher radiosensitization than either
approach alone
21
. Interestingly, few studies have succeeded to
develop dual EGFR/FAK small molecule inhibitors. In 2020, Ai et al.
has exploited a fragment-based drug design approach to identify
novel series of 2,4-diaminopyrimidines as potent dual EGFR/FAK
inhibitors with good in vitro and in vivo antitumor effects
20
.
Quinoline is an outstanding planar heterocyclic motif playing a
distinctive role in anticancer drug discovery. So far, assortments of
quinoline-based small molecules have been developed and inves-
tigated against numerous biological targets for cancer treatment
displaying exquisite outcomes
2225
. It is worth stressing that
plenty of quinoline derivatives provoked their anticancer impact
through different mechanisms of action, such as inhibition of DNA
repair, tubulin polymerisation, and inhibition of various enzymes
implicated in critical cancer cell proliferation prominently kinases
enzymes (EGFR, VEGFR, pim-1 kinase, c-Met factor, and PI3K)
which stood out as one of the most significant targets imple-
mented in cancer therapy due to their functions in cellular signal
transduction
2630
. Of special interest, Pelitinib (EKB-569, Figure 2)
is a 4-anilinoquinoline derivative which is a potent irreversible
inhibitor of EGFR in the clinical trials as an anticancer candidate
24
.
In addition, several 4-aminoquinoline derivatives, such as com-
pounds IIII (Figure 2), were reported as promising EGFR inhibi-
tors endowed with effective anticancer activities. Accordingly,
quinoline stands out as a significant privileged scaffold in anti-
cancer drug discovery to develop many efficient kinases
inhibitors
24,3135
.
Recently, we have developed a new series of 6,7-dimethoxy-4-
alkoxy-2-arylquinolines as potential Topoisomerase I (TOP1) inhibi-
tors
36
. The TOP1-mediated DNA cleavage assay was utilised to
assess the ability of the reported compounds to stabilise TOP1-
DNA cleavage complexes (TOP1ccs). The assay outcomes revealed
a moderate TOP1 inhibitory activity of compounds IVa,b(Figure
2). Interestingly, the developed quinolines showed outstanding
anti-proliferative profile upon evaluation at the Developmental
Therapeutics Program (DTP) of the NCI-USA. Noteworthy, the
weightiness of incorporation of p-substituted phenyl at C-2, as
well as propyl linker at C-4 of the quinoline scaffold, was high-
lighted by the SAR study.
As a continuation for our previous study
36
novel five sets of 4-
propoxy-2-arylquinolines (6ao,8a,b,10a,b,12ad,16ad), and
4-propoxy-2,6-diarylquinolines (20af) are herein designed and
synthesised, exploiting the deduced SARs from the previous study,
with the aim to afford more potent anticancer TOP1 inhibitors
(Figure 2). Different structural modification strategies were
adopted seeking to enhance both anticancer and TOP1 inhibitory
activities of the lead compounds IVa,b(Figure 3).
First, diverse secondary alicyclic and aromatic amines, in add-
ition to different primary amines were appended to the propyl
linker to illuminate the influence of these moieties on the activity.
Also, we introduced the electron donating methyl group as well
as electron withdrawing Cl and CF
3
for more elucidation of the
electronic impact of p-substituent of the 2-phenyl. Likewise, the
heterocycles: 2-furyl and 2-thienyl were appended to para position
of the C2-phenyl moiety to explore their electronic and size
impact on the desired activity. Afterward, the 6,7-dimethoxy
groups were removed in some synthesised analogs to confirm
their significance. Moreover, the ring system was extended via
fusion of the quinoline motif with 1,3-dioxolane in attempt to
enhance the planar structure requisite for DNA intercalation which
may potentiate both anticancer and TOP1 poisoning effects.
Finally, a structural extension approach was utilised via grafting
the HBA-bearing 2-furyl and 4-methoxyphenyl moieties at C6 of
quinoline scaffold, hoping to enhance the hydrophobic interac-
tions (Figure 3). The designed 4-propoxy-2-arylquinolines were
prepared employing different synthetic procedures, and then
investigated for their anticancer and TOP1 inhibitory activities.
Although the target quinolines demonstrated potent antiproli-
ferative effect against different cancer cell lines, they showed no
or weak TOP1 poisoning influence. Accordingly, the promising
anticancer activity prompted us to search for the plausible
molecular mechanism for herein reported quinolines.
The diverse well-reported kinase inhibitory activities of quin-
oline-based small molecules, as mentioned above, motivated us to
explore the potential inhibitory activity of target 4-propoxy-2-
Figure 2. Some reported quinolines with potential anticancer activity.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 351
arylquinolines (6ao,8a,b,10a,b,12ad, and 16ad) and 4-pro-
poxy-2,6-diarylquinolines (20af) against various kinases (EGFR,
FAK, FRK, IGF-1R, BTK, c-Src, VEGFR-1, VEGFR-2, HER-2). Strikingly,
the investigated quinolines exhibited promising dual inhibitory
effect towards EGFR and FAK kinases. Moreover, the apoptotic
impact of the most potent anti-proliferative agents in this study
was investigated on DLD-1 cells exploiting AV/PI dual staining
assay. Finally, in silico molecular modelling techniques, including
docking and molecular dynamics studies, were exploited to justify
and support results obtained from the biological evaluations.
2. Results and discussion
2.1. Chemistry
The synthetic routes adopted for the synthesis of the target 4-pro-
poxy-2-arylquinolines (6ao,8a,b,10a,b,12ad, 16ad) and 4-
propoxy-2,6-diarylquinolines 20afare illustrated in Schemes 13.
Regarding Scheme 1, the benzamides 3acwere prepared by
reacting 4,5-dimethoxy-20-aminoacetophenone 1with p-substi-
tuted benzoyl derivatives 2acin dry THF and Et
3
N. The latter
were cyclized in refluxing dioxane and NaOH to afford the corre-
sponding quinolones 4acin excellent yields which then were
subjected to O-alkylation with 1-bromo-3-chloropropane using our
previously confirmed procedure to yield the respective 4-propoxy
key intermediates 5ac
36
. Finally, these key intermediates 5ac
were converted to the target 4-prpoxy-2-arylquinolines 6aoin
good to excellent yields (7080%) through nucleophilic substitu-
tion with the appropriate amine in dry DMF and potassium car-
bonate anhydrous using catalytic amount of potassium iodide
at 90 C.
In Scheme 2(A), the bromo analog of 4-propoxy-N-methylpiper-
azine-2-arylquinoline 7was obtained based on the same pathway
for 6aousing p-bromobenzoyl chloride. Then, this bromo analog
7has been transformed into the target heterocyclic derivatives
8a,b in good yields (7072%) under Suzuki cross coupling condi-
tion through its reaction with the appropriate boronic acid deriva-
tive in dioxane using tetrakis catalyst and 2 M sodium carbonate
under N
2
at 90 C. In Scheme 2(B,C), syntheses of the target deme-
thoxylated analogs 10a,b and 1,3-dioxolo analogs 12adhave
been accomplished in good to excellent yields (7287%) adopting
the same synthetic routes described for 6aousing the respective
starting compounds, intermediates, and amines.
Concerning Scheme 3, initiated from 5-bromo-20-aminoaceto-
phenone 13, the target 6-bromo analogs 16adhave been
afforded in good to excellent yields (7887%) applying the syn-
thetic routes utilised for 6ao. Moreover, 5-bromo-20-aminoaceto-
phenone 13 was transferred to the 6-aryl derivatives 17a,b via
Suzuki coupling reaction by its reaction with the appropriate bor-
onic acid derivative in dioxane/water in the presence of tetrakis
catalyst and potassium carbonate under N
2
at 100 C.
Subsequently, these 6-aryl derivatives 17a,b have been similarly
converted to the target 4-propoxy-2,6-diarylquinolnes 20afin
good to excellent yields (7489%) exploiting the same experimen-
tal pathways adopted for 6ao.
The structures of all synthesised compounds have been
authenticated employing one- dimensional (1D) and two-dimen-
sional (2D) NMR (for 2D NMR, see Supplementary Data), in add-
ition to high resolution mass spectrometry (HRMS).
2.2. 2.2. In vitro anticancer activity
2.2.1. Antiproliferative activity against different cancer cell lines
The in vitro antiproliferative activity of the synthesised 4-propoxy-
2-arylquinolines (6ao,8a,b,10a,b,12ad, and 16ad) and 4-
Figure 3. Different structural modification strategies adopted for design of target quinoline derivatives in this study.
352 M. M. ELBADAWI ET AL.
propoxy-2,6-diarylquinolines (20af) was preliminary investigated
by their screening at one dose level (10 mM) against five cancer
cell lines representing three cancer types; colorectal cancer (DLD-1
and HCT-116), breast cancer (MDMBA-231 and MCF-7) and cervical
cancer (HeLa). After the incubation of the tested compounds for
24 h, the percent growth inhibition (GI%) was calculated. For DLD-
1 cell line, twelve compounds exerted good to excellent growth
inhibition ranging from 71.94 to 95.36%, from them compounds
6f, 6h, 6i, 16d, 20e, and 20f displayed the highest GI%. Similarly,
HCT-116 cell line established good to excellent sensitivity to the
tested compounds and thirteen compounds exhibited GI% rang-
ing from 64.26 to 97.48%, from them compounds 6d, 6f, 6h, 6i,
12c, 16b, 16d, 20e, and 20f demonstrated the best sensitivity
(Table 1).
Regarding breast cancer cell lines, GI% ranged from 75.34 to
84.76% and 71.97 to 87.36% for MDMBA-231 and MCF-7 cell lines,
respectively. While five compounds showed good inhibitory activ-
ity towards MDMBA-231, ten compounds possessed good inhib-
ition to the growth of MCF-7 cancer cell line. For HeLa cell line,
seven compounds had good GI% from 65.73 to 90.78%. Based on
the preceding screening results, it was revealed that colorectal
cancer cell lines (DLD-1 and HCT-116) were the most sensitive to
the tested compounds, therefore they were selected for further
antiproliferative assay at six doses levels (Table 1).
The growth inhibitory activity of the tested 4-propoxy-2-aryl-
quinolines (6ao,8a,b,10a,b,12ad, and 16ad) and 4-propoxy-
2,6-diarylquinolines 20afexerted on the colorectal cancer cell
lines (DLD-1 and HCT-116) was assessed using MTT assay. DLD-1
and HCT-116 cell lines were incubated for 24 h with increasing
concentrations (0.5, 1, 10, 30, 50, and 100 mM) of the tested com-
pounds. Gefitinib (EGFR inhibitor) and TAE226 (FAK inhibitor) were
used as reference drugs. The results were presented as half max-
imal growth inhibitory concentration (IC
50
) which represents the
concentration of a drug exhibiting 50% growth inhibition of the
cell line compared to the negative control (Table 2).
The antiproliferative investigations against DLD-1 revealed that
compound 6h emerged as the most potent counterpart showing
IC
50
¼1.79 mM surpassing the activity of Gefitinib by 5-folds which
possessed IC
50
¼10.24 mM. Thereafter, compounds 6f,6i,16d,
and 20f displayed 4-folds superior activity compared to Gefitinib
with IC
50
values ¼2.25, 2.48, 2.18, and 2.09 mM, respectively. In
addition, compounds 6d,6l,6n,8b,12b,12c,16a,16b,20b, and
20e exerted better inhibitory activity than Gefitinib demonstrating
IC
50
values ¼8.15, 6.34, 6.11, 7.34, 8.36, 9.12, 8.22, 8.69, 9.65, and
4.46 mM, respectively. The rest of compounds had week to moder-
ate or no activity relative to Gefitinib.
Concerning HCT-116 cell line, it was found that compounds 6f,
6h,16d, and 20f established twice inhibitory activity compared to
Gefitinib (IC
50
¼6.94 mM) displaying IC
50
values ¼3.09, 3.28, 2.43,
and 2.96 mM, respectively. Furthermore, compounds 6d,6i,12c,
16a,16b, and 20e exhibited higher growth inhibitory activities
than Gefitinib with IC
50
values ¼4.67, 5.68, 6.37, 6.15, 4.22, and
4.75 mM, respectively. The remaining compounds possessed week
to moderate or no activity compared to Gefitinib.
It is noteworthy that appending p-CF
3
to the 2-phenyl
enhanced the antiproliferative activity compared to p-Cl and p-
CH
3
, except for the cyclohexylamine analogs 6b, 6g, and 6l in
which the p-CH
3
substituent is preferred for antiproliferative activ-
ity. Remarkably, the incorporation of p-(2-furyl) to the 2-phenyl
abolished the growth inhibitory activity, while the introduction of
p-(2-thienyl) increased the activity compared to p-Cl and p-CH
3
analogs. In the context of impact of amine substituents on the
Scheme 1. Synthesis of target 4-propoxy-2-arylquinolines 6ao; Reagents and conditions: (i) Et
3
N, THF, 0 C then rt, overnight; (ii) dry dioxane, NaOH, reflux under N
2
,
110 C, 4 h; (iii) KI, KOH, 1-Bromo-3-chloropropane, dry DMF, rt, 24 h; (iv) KI, K
2
CO
3
anhydrous, appropriate amine, dry DMF, reflux, 90C, 12 h.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 353
antiproliferative activity, it was proved that 4-amino-N-methylpi-
peridine is preferred for anticancer activity, then piperazine, tetra-
hydrofurfurylamine and cyclohexylamine. Notably, grafting
imidazole along with 6,7-dimethoxy substituents abolished the
antiproliferative activity for all derivatives.
Besides, the removal of 6,7-dimethoxy groups from the quin-
oline scaffold decreased or abolished activity. While the fusion of
1,3-dioxolo to the quinoline scaffold along with p-CF
3
substitution
on phenyl dramatically potentiated the anticancer activity of the
imidazole derivatives, the replacement of imidazole with morpho-
line decreased the activity of p-CF
3
analogs and markedly
increased the activity of p-Cl counterparts. On the other hand,
appending of electron withdrawing (Br) to position 6 of quinoline
parallel with p-Cl substitution on 2-phenyl greatly enhanced the
activity of the imidazole derivatives while, p-F substitution on the
2-phenyl extremely decreased the anticancer activity of imidazole
derivatives. Also, the replacement of imidazole with morpholine
almost had no impact on the p-Cl analogs, but tremendously ele-
vated the anticancer activity of p-F derivatives.
Furthermore, the incorporation of 4-methoxyphenyl or 2-furyl
to position 6 of quinoline along with p-Cl or F on the 2-phenyl
enhanced the activity of the imidazole derivatives compared to
the dimethoxy analogs, but the 2-furyl derivatives exhibited better
activity. Moreover, the replacement of imidazole with morpholine
elevated the antiproliferative activity of p-Cl analogs while, dimin-
ished the activity of p-F derivatives.
Finally, the deduced structure activity relationships indicated
that the substitution pattern on positions 6 and 7 of quinoline
and position 4 of the 2-phenyl, in addition to the amine substitu-
tion on the 4-propoxy linker are crucial elements for the anti-
cancer activity. In general, incorporation of dimethoxy groups at
positions 6 and 7 of quinoline along with p-CF
3
at 2-phenyl and
4-amino-N-methylpiperidine, piperazine or tetrahydrofurfurylamine
on the 4-propoxy linker, in addition to grafting of electron with-
drawing (Br) or 2-furyl at position 6 of quinoline along with p-F or
Cl on the 2-phenyl and morpholine on the propoxy linker resulted
in the most potent antiproliferative agents in this study.
2.2.2. Annexin V-FITC/propidium iodide apoptosis assay (AV/PI)
The apoptotic impact of the most potent antiproliferative agents
6f, 6h, 6i, 16d, and 20f on DLD-1 colorectal cancer cell line was
Scheme 2. Synthesis of target 4-propoxy-2-arylquinolines (A) 8a,b; (B) 10a,b; (C) 12ad; Reagents and conditions: (i) Pd(PPh
3
)
4
,2MNa
2
CO
3
, Arylboronic acid, dioxane,
90 C under N
2
, 16 h. (ii) KI, K
2
CO
3
anhydrous, the respective amine, dry DMF, reflux, 90C, 12 h.
354 M. M. ELBADAWI ET AL.
investigated exploiting AV/PI dual staining assay. The assay out-
comes proved that the tested compounds elicited apoptosis of
such cell line as indicated by significant rise in the total percent-
age of AV positive apoptotic DLD-1 cells compared to the control
(Figure 4). Compound 6h increased the total percentage of apop-
totic cells from 7% for the control to 90.33%. Also, compounds 6f,
6i, 16d, and 20f exerted potential apoptotic effect elevating the
total percentage of apoptotic cells to 84.33, 71.66, 51.66, and
80.66%, respectively.
2.3. Topoisomerase I-mediated DNA cleavage assay
TOP1 poisoning activity of all target compounds has been esti-
mated utilising TOP1-mediated DNA cleavage assay that deter-
mines the TOP1 poisoning activity relative to 1 mM Camptothecin
(CPT)
37
. The tested compounds were incubated at 0.1, 1, 10, and
100 mM with recombinant human TOP1 enzyme and a 30-[
32
P]-
labeled 117-bp DNA oligonucleotide
38
. TOP1 poisoning agents
specifically trap TOP1ccs leading to their stabilisation and DNA
cleavage. The drug-induced stabilised TOP1ccs are visualised by
gel electrophoresis demonstrating specific DNA cleavage patterns.
Then a semiquantitative scoring system by visual comparison
between lanes induced by the target compounds and 1 mM CPT
was used to score the compounds (Table 3, see Supplementary
Data for the results of gel electrophoresis)
3941
.
Compounds 6ae, 6h, 6l, 6m, 12a, and 12b exhibited weak
TOP1 poisoning effect (-/þ) displaying DNA cleavage activity equal
to 025% of the activity of 1 mM CPT, while compound 16c dem-
onstrating activity (þ) equals to 2550% of the activity of 1 mM
CPT. The rest of compounds possessed no cleavage activity.
Despite the target compounds showing promising antiproliferative
activity against cancer cell lines, their TOP1 poisoning activities
were not encouraging for further development as potent TOP1
inhibitors. Accordingly, the synthesised compounds have been
evaluated for the plausible mechanism by which they provoked
the antiproliferative activity.
2.4. Kinase inhibitory activities of target quinolines
2.4.1. Kinase profiling
The non-significant TOP1 poisoning activities of target compounds
obtained from Topoisomerase I-mediated DNA cleavage assay
motivated us to search for the plausible molecular mechanism for
herein reported 4-propoxy-2-arylquinolines.
The potential inhibitory activity of the target 4-propoxy-2-aryl-
quinolines (6ao,8a,b,10a,b,12ad,16ad) and 4-propoxy-2,6-
Scheme 3. Synthesis of the target 6-bromo-4-propoxy-2-arylquinolines 16adand 4-propoxy-2,6-diarylquinolines 20af; Reagents and conditions: (i) the respective
benzoyl chloride, Et
3
N, THF, 0 C then rt, overnight; (ii) dry dioxane, NaOH, reflux under N
2
,110
C, 4 h; (iii) KI, KOH, 1-Bromo-3-chloropropane, dry DMF, rt, 24 h; (iv) KI,
K
2
CO
3
anhydrous, the respective amine, dry DMF, reflux, 90C, 12 h; (v) K
2
CO
3
, Pd(PPh
3
)
4
, Arylboronic acid, dioxane/H
2
O (1:1), 100 C under N
2
,4h.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 355
diarylquinolines (20af) was explored against a panel of nine kin-
ases representing different signalling pathways; EGFR, FAK, FRK,
IGF-1R, BTK, c-Src, VEGFR-1, VEGFR-2 and HER-2 (see
Supplementary Data,Table S1). The half maximal inhibitory con-
centration (IC
50
) values were calculated for each kinase and pre-
sented in Table S1 and Table 4. Strikingly, the screening outcomes
revealed that the investigated quinolines exhibited promising dual
inhibitory effect towards EGFR and FAK kinases.
2.4.2. EGFR and FAK kinase inhibitory activity
All the newly prepared 4-propoxy-2-arylquinolines (6ao,8a,b,
10a,b,12ad, and 16ad) and 4-propoxy-2,6-diarylquinolines
(20af) were examined for their potential EGFR and FAK inhibitory
activities. Gefitinib and TAE-226 were used as reference EGFR and
FAK inhibitors, respectively. The results are reported as half max-
imal inhibitory concentration values (IC
50
), as determined from
triplicate measurements and are presented in Table 4.
Results in Table 4 revealed that the examined quinolines dis-
played moderate to potent inhibitory activity towards EGFR (IC
50
values ranging between 20.15 ± 1.07 and 485.46 ± 11.37 nM, Table
4). In particular, trifluoromethyl phenyl-bearing 6,7-dimethoxy-2-
arylquinolines 6f,6h, and 6i, as well as 6-furanyl-2-arylquinoline
20f emerged as the most efficient EGFR inhibitors with two-digits
nanomolar IC
50
s (IC
50
¼25.39 ± 3.49, 20.15 ± 1.07, 22.36 ± 2.05, and
24.81 ± 2.71 nM, respectively). Notably, these four derivatives dis-
played 2-fold higher activity than the reference EGFR inhibitor
Gefitinib (IC
50
¼48.52 ± 3.64 nM). In addition, compounds 6b,6d,
6l,6n,8b,16d, and 20e exhibited potent EGFR inhibitory activity,
as the measured IC
50
values ranged between 33.65 ± 1.02 and
46.37 ± 4.09 nM, which are slightly improved or comparable to
that of the reference drug Gefitinib (Table 4). Moreover, com-
pounds 6c and 12b showed 2-fold decreased activity (IC
50
¼
85.67 ± 6.46 and 95.36 ± 2.05 nM, respectively) than Gefitinib
against EGFR. The remaining examined quinolines possessed
moderate EGFR inhibitory activity (IC
50
range: 121.74 ± 9.40
485.46 ± 11.37 nM) compared to Gefitinib (Table 4). Strikingly, the
inclusion of 4-amino-N-methylpiperidine, tetrahydrofurfurylamine
and N-methylpiperazine along with 2-(p-CF
3
phenyl) and 6,7-dime-
thoxy substituents (6f, 6h, and 6i), in addition to the grafting of
morpholine together with 2-(p-Cl phenyl) and 6(2-furyl) 20f
afforded the most potent EGFR inhibitors in this study displaying
IC
50
range from 20.15 ± 1.07 to 25.39 ± 3.49 nM.
On the other hand, as depicted in Table 4, FAK kinase was effi-
ciently inhibited by all 4-propoxy-2-arylquinolines (6ao, 8a,b,
10a,b, 12ad, and 16ad) and 4-propoxy-2,6-diarylquinolines
(20af) herein reported in the nanomolar range (IC
50
range:
14.25 ± 2.72298.74 ± 1.94 nM). Superiorly, p-CF
3
-phenyl-bearing
6,7-dimethoxy-2-arylquinolines 6f,6h, and 6i, as well as, morpho-
line-bearing 6-bromo-2-arylquinoline 16d and 6-furanyl-2-arylqui-
noline 20f were the most potent FAK inhibitors in this study with
Table 1. % Growth inhibition (GI%) of all target compounds 6ao, 8a,b, 10a,b,
12ad, 16ad, and 20afagainst different cancer cell lines at 10 mM dose level.
Compounds
GI%
DLD1 HCT-116 MDMBA-231 MCF-7 Hela
6a 22.56 31.34 9.38 17.34 20.15
6b 36.25 42.81 19.67 23.49 12.81
6c 28.22 41.36 19.38 15.76 4.96
6d 75.64 82.61 63.39 71.97 26.98
6e 15.79 22.03 4.67 5.34 22.36
6f 95.36 88.46 75.34 94.36 69.17
6g 25.36 22.16 48.15 76.38 46.28
6h 92.36 89.34 84.76 90.36 90.78
6i 88.76 82.11 81.60 89.49 78.64
6j 6.31 2.46 8.42 14.67 5.67
6k 18.69 22.15 8.64 17.49 11.32
6l 75.34 69.15 38.36 44.71 34.29
6m 22.16 24.31 8.16 22.09 30.19
6n 81.34 64.26 14.39 58.15 71.12
6o 12.36 1.08 8.64 5.36 9.16
8a 5.15 1.02 4.40 7.22 11.78
8b 74.25 52.10 36.87 74.90 50.81
10a 22.51 18.64 37.15 14.26 25.64
10b 35.72 24.10 45.35 64.81 55.49
12a 21.25 16.25 4.98 11.72 22.79
12b 72.95 31.28 14.28 64.38 25.39
12c 71.94 80.49 61.94 43.27 68.22
12d 22.58 54.37 9.36 26.54 36.67
16a 60.08 76.17 51.24 22.97 47.35
16b 55.82 87.61 45.31 19.38 35.94
16c 12.25 18.14 20.11 4.36 8.67
16d 90.11 97.48 80.24 86.38 85.67
20a 44.98 36.71 29.08 15.23 22.06
20b 53.15 71.05 48.31 29.37 34.02
20c 41.34 38.64 32.11 76.82 22.08
20d 24.65 36.91 27.05 15.34 11.97
20e 90.65 89.64 56.29 73.61 65.73
20f 94.18 91.37 82.58 87.36 79.64
Table 2. The half maximal growth inhibitory concentration (IC
50
) of all target compounds 6ao, 8a,b, 10a,b, 12ad, 16ad, and
20afagainst two colorectal cancer cell lines (DLD1 and HCT-116) compared to Gefitinib and TAE226.
Compounds
IC
50
(mM)
a
Compounds
IC
50
(mM)
DLD1 HCT-116 DLD1 HCT-116
6a >100 65.36 ± 4.37 10b 40.28 ± 2.09 >100
6b 19.37 ± 2.15 16.79 ± 1.56 12a >100 >100
6c 46.95 ± 2.46 13.70 ± 1.29 12b 8.36 ± 1.08 14.36 ± 3.69
6d 8.15 ± 1.05 4.67 ± 0.85 12c 9.12 ± 2.11 6.37 ± 1.09
6e >100 >100 12d 74.94 ± 5.46 9.20 ± 2.49
6f 2.25 ± 0.96 3.09 ± 1.05 16a 8.22 ± 1.12 6.15 ± 1.30
6g 75.36 ± 5.46 46.82 ± 3.16 16b 8.69 ± 2.64 4.22 ± 1.05
6h 1.79 ± 0.21 3.28 ± 0.67 16c >100 88.05 ± 5.24
6i 2.48 ± 0.86 5.68 ± 1.42 16d 2.18 ± 0.52 2.43 ± 0.71
6j >100 >100 20a 13.05 ± 3.69 24.11 ± 2.46
6k >100 >100 20b 9.65 ± 2.15 7.34 ± 1.82
6l 6.34 ± 0.52 8.11 ± 1.04 20c 15.97 ± 1.10 12.49 ± 3.05
6m 54.21 ± 2.11 43.08 ± 1.05 20d 65.30 ± 5.36 29.47 ± 4.15
6n 6.11 ± 1.80 8.69 ± 0.94 20e 4.46 ± 0.65 4.75 ± 1.02
6o >100 >100 20f 2.09 ± 0.14 2.96 ± 0.12
8a >100 >100 Gefitinib 10.24 ± 2.10 6.94 ± 1.24
8b 7.34 ± 1.22 9.84 ± 0.68 TAE226 0.12 ± 0.05 0.17 ± 0.04
10a >100 >100
a
IC
50
values are the mean of three separate experiments ± SD.
356 M. M. ELBADAWI ET AL.
IC
50
values equal 22.68 ± 2.38, 14.25 ± 2.72, 18.36 ± 3.17,
17.36 ± 2.15, and 15.36 ± 0.98 nM, respectively (Table 4). Moreover,
compounds 6c,6d,6l,6n,8b,16a,16b, and 20e exerted potent
FAK inhibitory activity with IC
50
spanning in the range
25.36 ± 3.4850.36 ± 4.81 nM.
Further analysis of the obtained results in Table 4 revealed that
compounds 6b,12b, and 20acexhibited two-digit nanomolar
IC
50
s; 98.16 ± 4.67, 70.85 ± 3.16, 77.25 ± 4.37, 63.25 ± 3.25, and
91.03 ± 5.85nM, respectively, whereas the remaining derivatives
displayed moderate inhibitory activity against FAK kinase (IC
50
range: 111.06 ± 8.94298.74 ± 1.94 nM) (Table 4). Interestingly, the
incorporation of 4-amino-N-methylpiperidine, tetrahydrofurfuryl-
amine and N-methylpiperazine along with 2-(p-CF
3
phenyl) and
6,7-dimethoxy substituents (6f, 6h, and 6i), besides the appending
of morpholine with 2-(p-F phenyl) and 6-Br 16d, as well as the
addition of morpholine in conjunction with 2-(p-Cl phenyl) and
6(2-furyl) 20f provided the most potent FAK inhibitors in this
study demonstrating IC
50
values ranging from 14.25 ± 2.72
to 22.68 ± 2.38 nM.
It is worth stressing that 4-propoxy-2-arylquinolines 6f,6h,6i,
and 20f emerged not only as the most potent dual EGFR/FAK
inhibitors in this study, but also as the most efficient anti-prolifera-
tive agents towards the examined colorectal cancer (DLD-1 and
HCT-116) cell lines.
2.5. In silico molecular docking
2.5.1. Docking into EGFR binding site
The molecular docking approach was utilised to investigate the
potential binding of herein reported 4-propoxy-2-arylquinolines to
EGFR binding site (PDB: 1M17). The docking procedure was vali-
dated through the redocking of the co-crystalised ligand. The cor-
rect pose was predicted accurately with RMSD of 1.498 between
the docked and co-crystalised ligand using DockRMSD server
(Figure 5(a))
42
. In addition, docking was able to maintain hydrogen
bonding seen in the co-crystalised ligand with NH of M769 (2.7 Å)
and with the NH of G772 (3.2 Å). Furthermore, hydrophobic inter-
actions with residues in the active site were also maintained.
These include interactions between K721 and ethyne benzene
moiety, and L694, L768, and L820 with hydrophobic part of the
quinazoline ring (Figure 5(b)).
Docking scores of the tested compounds with EGFR are
shown in Table 5. The docking score of the co-crystalised ligand
was 7.2 kcal/mol, whereas all the tested quinolines have
shown better docking scores than that of the co-crystalised lig-
and (7.9 to 9.7 kcal/mol). Best docking scores were seen with
quinolines form the series 20.Compound20c showed the best
binding energy to EGFR with docking score of 9.7 kcal/mol
anditsbindingposeisshowninFigure 5(c).Thecompound
Figure 4. Influence of the promising compounds on the total percentage of AV-FITC positive staining in DLD1 cancer cell line.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 357
has formed 2 hydrogen bonds between imidazole ring and
both K721 (3.5 Å) and T766 (3.1 Å). Also, several hydrophobic
interactions have been seen, which included interactions
between quinoline ring and side chains of V702 and T830. The
phenyl ring at position 2 formed hydrophobic interactions with
L694 and L820 which are also common with the co-crystalised
ligand. In addition, p-pstacking between the ring at quinoline
position 6 and F699.
Another compound from this series is compound 20e which
was selected as a representative example because it has shown
good biological results with both EGFR and FAK. The docking
pose of this compound is shown in Figure 5(d) showing a simi-
lar docking pose to 20c. The same hydrogen bonds with K721
(3.5Å)andT766(3.1Å)weremaintainedaswellashydrophobic
interactions with V702 and T830 as well as with L694 and L820.
The ppstacking was also seen between F699 and the furan
ring of 20e. This compound, in complex with EGFR, was sub-
jected to further investigation using molecular dynamics to
study the stability of its complex with EGFR as will be dis-
cussed later.
2.5.2. Docking into FAK binding site
Potential binding of target quinolines to FAK was also investigated
using docking studies (PDB: 2JKM). Initially, the docking procedure
was validated through the redocking of the co-crystalised ligand
(AZW592). The docking searching algorithm was able to correctly
predict the binding pose with acceptable accuracy with RMSD of
1.318 between the docked and co-crystalised ligands as predicted
by DockRMSD server (Figure 6(a))
42
. The docked structure was
able to maintain same hydrogen bonds that are in the crystal
structure including those between the sulphamoyl moiety oxygen
and the terminal amino group of K454 (Å) and the hydrogen
bond with the a-carbonyl group of C502. In addition, several
hydrophobic interactions have been also seen with residues in the
active site including I428, V436, V484, L501, and L553
(Figure 6(b)).
Next, target synthesised quinolines were docked in the active
site of the FAK after their preparation. The docking scores of
tested compounds are shown in Table 5. The docking score of
co-crystalised ligand (AZW592) was found to be 8.5 kcal/mol.
Some of tested compounds have shown scores that are compar-
able to the co-crystalised ligand. Best results were seen with 12
and 20 and some of the 16 series. Docking poses of these com-
pounds were similar with most of the docked compounds as can
be seen in Figure 6(c) which shows docking pose of some com-
pounds from these series.
Docking pose of compound 20e which was chosen as repre-
sentative example is shown in Figure 6(d). The compound was
able to form 3 hydrogen bonds with N551 (3.1 Å), D564 (3.1 Å),
and E506 (3.3 Å). In addition, several hydrophobic interactions
were also seen, such as the hydrophobic interaction between
quinoline ring and L553 and between phenyl ring at position 2
and I428 which are common with the co-crystallized ligand. This
pose was selected for further investigation of the complex stability
using molecular dynamics study.
2.6. Molecular dynamics (MD) simulation
The stability of compound 20e complexes with both EGFR and
FAK was investigated using 100 ns molecular dynamics studies.
With each complex, the results were compared with the
Table 3. The TOP1 inhibitory activity of all target compounds 6ao, 8a,b,
10a,b, 12ad, 16ad, and 20afcompared to Camptothecin (CPT).
Compounds
TOP1 inhibitory
activity
a
Compounds
TOP1 inhibitory
activity
6a /þ10a 0
6b /þ10b 0
6c /þ12a /þ
6d /þ12b /þ
6e /þ12c 0
6f 012d 0
6g 016a 0
6h /þ16b 0
6i 016c þ
6j 016d 0
6k 020a 0
6l /þ20b 0
6m /þ20c 0
6n 020d 0
6o 020e 0
8a 020f 0
8b 0
a
Scoring: 0: no activity; /þ:025% 1 mM CPT; þ:2550% 1 mM CPT.
Table 4. The half maximal inhibitory concentration (IC
50
) of all target compounds 6ao, 8a,b, 10a,b, 12ad, 16ad, and 20af
against EGFR and FAK kinase activity compared to Gefitinib and TAE226.
Compounds
IC
50
(nM)
a
Compounds
IC
50
(nM)
EGFR FAK EGFR FAK
6a 142.64 ± 2.54 214.36 ± 1.09 10b 179.64 ± 9.12 164.74 ± 5.37
6b 45.26 ± 5.36 98.16 ± 4.67 12a 124.97 ± 7.94 225.46 ± 14.02
6c 85.67 ± 6.46 45.70 ± 3.40 12b 95.36 ± 2.05 70.85 ± 3.16
6d 46.37 ± 4.09 36.97 ± 2.34 12c 246.70 ± 12.29 111.06 ± 8.94
6e 156.72 ± 11.36 211.08 ± 8.96 12d 450.16 ± 4.25 273.16 ± 2.84
6f 25.39 ± 3.49 22.68 ± 2.38 16a 222.15 ± 8.25 44.15 ± 3.26
6g 365.49 ± 14.82 145.71 ± 10.54 16b 313.34 ± 15.34 50.36 ± 4.81
6h 20.15 ± 1.07 14.25 ± 2.72 16c 485.46 ± 11.37 224 ± 10.46
6i 22.36 ± 2.05 18.36 ± 3.17 16d 35.03 ± 2.64 17.36 ± 2.15
6j 258.34 ± 11.94 186.46 ± 6.22 20a 121.74 ± 9.40 77.25 ± 4.37
6k 410.38 ± 12.73 157.84 ± 8.73 20b 245.11 ± 12.34 63.25 ± 3.25
6l 34.91 ± 3.76 26.37 ± 2.81 20c 362.30 ± 5.26 91.03 ± 5.85
6m 154.29 ± 12.80 172.49 ± 13.67 20d 146.95 ± 8.37 125.38 ± 3.15
6n 41.82 ± 2.34 44.36 ± 2.94 20e 33.65 ± 1.02 25.36 ± 3.48
6o 256.19 ± 6.94 204.84 ± 8.04 20f 24.81 ± 2.71 15.36 ± 0.98
8a 349.37 ± 14.05 198.32 ± 12.32 Gefitinib 48.52 ± 3.64 ̶
8b 35.48 ± 1.50 29.79 ± 2.37 TAE226 ̶4.60 ± 0.94
10a 244.30 ± 8.41 298.74 ± 1.94
a
IC
50
values are the mean of three separate experiments ± SD.
358 M. M. ELBADAWI ET AL.
co-crystalised ligand complex as a control and with the apopro-
tein (the protein alone with no ligands). The missing loops in
both targets were built using Swiss-Model server
43
before starting
the dynamics to ensure correct results. All complexes were
equilibrated under NVT then NPT conditions for 1 ns each and the
analysis was done on the production run.
Analysis of the production runs trajectories for 20e in the
active site of EGFR demonstrated stability comparable to the co-
crystalised ligand. Radius of gyration (R
g
) is a measure of the com-
pactness of the complexes. Stable R
g
suggested the stability of
the protein or complex under investigation. Figure 7(a) shows a
plot of R
g
of 20e, co-crystalised ligand and apoprotein. The aver-
age R
g
was found to be 2.01 ± 0.02, 2.03 ± 0.02, and 2.02 ± 0.01 nm
for apoprotein, control, and 20e, respectively. In addition, Root
mean square fluctuation (RMSF) of protein residue (Figure 7(b))
for all the three complexes showing similar patterns. The average
RMSF for co-crystalised ligand and 20e was found to be 0.19 and
0.18 nm, respectively which is slightly higher than that of the apo-
protein (0.15 nm). Although root mean square deviation (RMSD) of
ligand heavy atoms for 20e is slightly higher than that of the co-
crystalised ligand (Figure 7(c)), the value is <1 nm for most of the
trajectory. This value cannot be calculated for the apoprotein as it
has no ligand in the system. Finally, the number of hydrogen
bonds between ligands and protein are shown in Figure 7(d),
which showed that 20e formed extra hydrogen bonds during at
least 50% of the production run time. These results suggested
that 20e complex with EGFR is at least of comparable stability
when compared to the complex with the co-crystalised lig-
and; Erlotinib.
Complexes of FAK with 20e, its co-crystalised ligand and the
apoprotein showed similar pattern to that of the EGFR (Figure
8). This includes the radius of gyration (R
g
), which showed an
average of 2.00 ± 0.01, 1.99 ± 0.01, and 1.96 ± 0.01 nm for apo-
protein, co-crystalised ligand, and 20e, respectively (Figure
8(a)). Also, RMSF of protein residues was found to follow similar
patterns for all the three studied systems (Figure 8(b)). The
average RMSF for the three systems was found to be
0.12 ± 0.07, 0.13 ± 0.09, and 0.12 ± 0.07 nm for apoprotein, co-
crystalised ligand, and 20e, respectively. In addition, plotting of
RMSD of ligand heavy atoms (Figure 8(c)) showed minimal fluc-
tuation for both with and average RMSD of 0.19± 0.05 and
Figure 5. Docking of target quinolines in the active site EGFR. (a) validation of docking procedure showing overlapping of crystalised (blue) and docked (pink) poses;
(b) interactions of Erlotinib with EGFR; (c) docking pose of 20c; (d) docking pose of 20e.
Table 5. Docking results of target compounds with EGFR and FAK.
Compound
Docking Score (kcal/mol)
EGFR (PDB: 1M17) FAK (PDB: 2JKM)
6a 8.1 7.7
6b 8.5 7.3
6c 8.2 7.5
6d 7.9 7
6e 8.4 7.6
6f 8.2 7.4
6g 8.5 7.6
6h 8.2 7.6
6i 8.1 7.3
6j 8.6 8.0
6k 8.1 7.7
6l 8.7 7.4
6m 8.3 7.5
6n 8.2 7.1
6o 8.4 7.7
8a 8.3 7.6
8b 8.4 7.5
10a 8.8 7.9
10b 8.3 8.0
12a 8.5 8.0
12b 8.5 8.3
12c 8.8 8.4
12d 8.7 8.3
16a 8.1 7.7
16b 8.2 8.0
16c 8.3 7.7
16d 8.3 7.9
20a 9.3 8.3
20b 9.1 8.2
20c 9.7 8.3
20d 9.2 8.2
20e 9.3 8.2
20f 8.8 7.7
Co-crystalised ligand 7.2 (Erlotinib) 8.5 (AZW592)
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 359
0.57 ± 0.16 nm for co-crystalised ligand and 20e,respectively.
Although, the value for 20e ishigherbutitiswithinacceptable
range (<1nm).Finally,plottingofhydrogenbondsbetween
ligands and target protein (Figure 8(d)) showed that the
number of hydrogen bonds is higher in case of the co-crystal-
ised ligand compared to 20e.Beingsaid,20e was still able to
maintain an average of 1.93 ± 0.45 hydrogen bonds during the
100 ns production run.
Figure 6. Docking of target compounds in the active site FAK. (a) validation of docking procedure showing overlapping of crystalised (blue) and docked (pink) poses;
(b) interactions of AZW592 with FAK; (c) general binding of 16 and 20 compound series; (d) docking pose of 20e.
Figure 7. Molecular dynamics analysis of the production run trajectory of 20e in the active site of EGFR compared to control and apoprotein. (a) Radius of gyration;
(b) Root mean square fluctuation of residues; (c) Root mean square deviation of ligand heavy atoms; (d) Number of hydrogen bonds between ligand and protein.
360 M. M. ELBADAWI ET AL.
These results collectively suggested the stability of compound
20e complexes with both EGFR and FAK compared to the corre-
sponding co-crystalised ligands in each target. This in general sup-
ported the dual mechanism similar to the enzymatic
inhibition data.
3. Conclusion
Different series of 4-propoxy-2-arylquinolines (6ao, 8a,b, 10a,b,
12ad, and 16ad) and 4-propoxy-2,6-diarylquinolines (20af)
have been designed and synthesised as potential anticancer
agents. The quinolines 6f,6h,6i,16d, and 20f demonstrated the
most potent antiproliferative effect against DLD-1 colorectal can-
cer with respective IC
50
values ¼2.25, 1.79, 2.48, 2.18, and
2.09 mM with 4- to 5-folds potency compared to Gefitinib (IC
50
¼
10.24 mM). Additionally, compounds 6f,6h,16d, and 20f pos-
sessed twice growth inhibitory impact as Gefitinib (IC
50
¼
6.94 mM) displaying IC
50
values ¼3.09, 3.28, 2.43, and 2.96 mM
against HCT-116 cell line, respectively. Moreover, compounds 6f,
6h,6i,16d, and 20f significantly elevated the total percentage of
DLD-1 apoptotic cells. Furthermore, the quinolines 6f,6h,6i, and
20f exerted potent EGFR inhibitory effects with IC
50
values ¼
25.39 ± 3.49, 20.15 ± 1.07, 22.36 ± 2.05, and 24.81 ± 2.71 nM,
respectively compared to Gefitinib (IC
50
¼48.52 ± 3.64 nM). In a
similar fashion, the quinolines 6f,6h,6i,16d, and 20f displayed
the best FAK inhibitory actions with IC
50
values ¼22.68 ± 2.38,
14.25 ± 2.72, 18.36 ± 3.17, 17.36 ± 2.15, and 15.36 ± 0.98 nM,
respectively. Molecular docking and molecular dynamics simula-
tion rationalised EGFR/FAK dual inhibition providing different qui-
nolines being as the first reported quinolines possessing potential
EGFR/FAK dual inhibition. The latter compounds can be used as
lead compounds for the development of more potent EGFR/FAK
dual inhibitors as potential anticancer agents.
4. Experimental
4.1. Chemistry
4.1.1. General
Melting points have been measured by Yanaco melting point
device and were uncorrected. NMR spectra were measured using
Bruker Advance III HD at 400 MHz for
1
H NMR, 100 MHz for
13
C
NMR and 376 MHz for
19
F NMR in deuterated CDCl
3
or DMSO-d
6
using tetramethyl silane (TMS) as an internal standard. Coupling
constant values (J) were determined in Hertz (Hz) and chemical
shifts (d) were expressed in ppm. High resolution mass spectrom-
etry (HRMS) have been measured by Thermo Fisher Scientific LTQ
Orbitrap XL spectrophotometer using electrospray ionisation (ESI)
and the results were expressed as [M þH]
þ
or [M þNa]
þ
at
Natural Science Research and Development Centre, Hiroshima
University, Japan. The purities of all biologically tested compounds
were determined by HPLC and were found to be 95%. HPLC
analysis was performed utilising JASCO 880-PU HPLC system
(Japan spectroscopic Co. Ltd) connected to a diode array detector
with detection at a wavelength of 254 nm. The column exploited
in the HPLC analysis was Inertsil ODS-3 column with dimensions
of 250 4.6 mm and 5 mm particle size (GL SCIENCES INC., Japan).
The mobile phase employed for HPLC analysis was acetonitrile/
water/TFA (29.9/70/0.1, v/v) at a flow rate of 0.5 ml/min. The reac-
tions have been monitored by thin layer chromatography (TLC)
using Merck silica gel 60F
254
aluminium sheets. Column chroma-
tography has been performed utilising silica gel 60 N, 63210 mm
that was purchased from Kanto Chemical Co. Inc., Japan using
Figure 8. Molecular dynamics analysis of the production run trajectory of 20e in the active site of FAK compared to control and apoprotein. (a) Radius of gyration; (b)
Root mean square fluctuation of residues; (c) Root mean square deviation of ligand heavy atoms; (d) Number of hydrogen bonds between ligand and protein.
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 361
dichloromethane/methanol (100/0 to 90/10, v/v) and hexane/eth-
ylacetate (100/0 to 90/10, v/v). Unless otherwise stated, all chemi-
cals and solvents were available commercially and have been
used without further purification.
4.1.2. Synthesis of 1-(2-amino-4,5-dimethoxyphenyl)ethan-1-
one (1)
20-Aminoacetophenone derivative 1was prepared using the
reported method
44,45
.
Yellow solid, yield 70%, m.p. 100102 C;
1
H NMR (400 MHz,
CDCl
3
)d(ppm): 2.53 (s, 3H, CH
3
), 3.85 (s, 3H, OCH
3
), 3.89 (s, 3H,
OCH
3
), 6.12 (s, 1H, phenyl CH), 6.27 (br s, 2H, NH
2
), 7.12 (s, 1H,
phenyl CH).
4.1.3. General procedure for the synthesis of benzamides (3ac)
In dry THF (8 ml) and Et
3
N (2 ml), 1(2-amino-4,5-dimethoxypheny-
l)ethan-1-one 1(0.976 g, 5 mmol) was dissolved and cooled in ice
bath. Then, a solution of the respective p-substituted benzoyl
chloride 2ac(5.1 mmol) in dry THF (2 ml) was added dropwise
while cooling in ice bath. The reaction mixture was stirred in ice
bath for 30 min and then overnight at room temperature. After
that, reaction mixture was poured into ice/water and the resulting
solid was filtered off and washed excessively with water and
methanol to afford the corresponding 3ac.
The spectral characterisation of the benzamides 3a,b were
reported in our previous study
36
.
4.1.3.1. N-(2-acetyl-4,5-dimethoxyphenyl)-4-methylbenzamide
(3c).White solid, yield 70%, m.p. 165167 C;
1
H NMR (400 MHz,
CDCl
3
)d(ppm): 2.42 (s, 3H, CH
3
), 2.65 (s, 3H, CH
3
C¼O), 3.91 (s, 3H,
OCH
3
), 4.02 (s, 3H, OCH
3
), 7.29 (d, 2H, benzoyl 2CH, J¼8.1 Hz),
7.30 (s, 1H, phenyl CH), 7.96 (d, 2H, benzoyl 2CH, J¼8.1 Hz), 8.77
(s, 1H, phenyl CH), 12.93 (s, 1H, NH);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 21.48, 28.37, 56.23, 56.43, 103.52, 113.90, 114.52, 127.45,
129.48, 132.01, 138.49, 142.49, 143.57, 154.89, 166.19 (C¼O), 201
(C¼O); HRESIMS (m/z): [M þH]
þ
Calcd for C
18
H
20
NO
4
, 314.13868;
found, 314.13901.
4.1.4. General procedures for synthesis of the quinolones (4ac)
Under N
2
atmosphere, the benzamides 3acand three equivalents
NaOH were refluxed in dry dioxane at 110 C for 4 h and then
cooled to room temperature. Small amount of water and excess
amount of hexane were added to the reaction mixture. The result-
ing mixture was subjected to sonication for 2 min and then neu-
tralised using 1 M HCl. The separated solid was filtered off and
washed excessively with water to give the corresponding quino-
lones 4ac.
The spectral data of the quinolones 4a,b have been reported
in our previous study
36
.
4.1.4.1. 6,7-dimethoxy-2-(p-tolyl)quinolin-4(1H)-one (4c). Yellow
solid, Yield 92%, m.p. >250 C;
1
H NMR (400 MHz, DMSO-d6)d
(ppm): 2.43 (s, 3H, CH
3
), 3.93 (s, 3H, OCH
3
), 3.96 (s, 3H, OCH
3
), 7.03
(s, 1H, vinyl CH), 7.47 (d, 2H, p-toluoyl 2CH, J¼8.1 Hz), 7.51 (s, 1H,
phenyl CH), 7.62 (s, 1H, phenyl CH), 7.84 (d, 2H, p-toluoyl 2CH,
J¼8.1 Hz);
13
C NMR (100 MHz, DMSO-d4)d(ppm): 21.43, 56.39,
56.62, 100.57, 102.37, 104.13, 115.90, 128.22, 130.19, 130.34,
137.47, 142.04, 149.30, 151.20, 155.22, 170. 10 (C¼O); HRESIMS (m/
z): [M þH]
þ
Calcd for C
18
H
18
NO
3
, 296.12812; found, 296.12827.
4.1.5. General procedure for synthesis of the key intermedi-
ates (5ac)
The quinolones 4ac(3 mmol), KI (0.498 g, 3 mmol) and KOH
(1.009 g, 18 mmol) were stirred for 2 h in dry DMF (30 ml) and
then 1-bromo-3-chloropropane (2.361 g, 15 mmol) was added to
the mixture and stirred at room temperature for 24 h. Thereafter,
the mixture was poured into ice/water and the separated solid
was filtered off and washed with water then hexane to furnish the
key intermediates 5acwhich were used without further
purification.
The spectral data of 5a,b have been reported in our previ-
ous study
36
.
4.1.5.1. 4-(3-chloropropoxy)-6,7-dimethoxy-2-(p-tolyl)quinoline
(5c). White solid, Yield 90%, m.p. 140142 C;
1
H NMR (400 MHz,
CDCl
3
)d(ppm): 2.42 (s, 3H, CH
3
), 2.43 (p, 2H, CH
2
,J¼6.1 Hz), 3.83
(t, 2H, CH
2
Cl, J¼6.2 Hz), 4.02 (s, 3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.42
(t, 2H, CH
2
-O, J¼6 Hz), 7.10 (s, 1H, vinyl CH), 7.30 (d, 2H, p-toluoyl
2CH, J¼8.1 Hz), 7.36 (s, 1H, phenyl CH), 7.44 (s, 1H, phenyl CH),
7.96 (d, 2H, p-toluoyl 2CH, J¼8.1 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 21.30, 32.01, 41.40, 56.05, 56.11, 64.81, 97.57, 99.58, 108.37,
114.64, 127.14, 129.43, 137.66, 138.87, 146.28, 148.88, 152.61,
156.97, 160.56; HRESIMS (m/z): [M þH]
þ
Calcd for C
21
H
23
ClNO
3
,
372.13610; found, 372.13623.
4.1.6. General procedure for synthesis of the target 4-propoxy-2-
arylquinolines (6ao)
To a stirred mixture of 5ac(1 mmol), anhydrous K
2
CO
3
(1.38 g,
10 mmol) and KI (0.83 g, 5 mmol) in dry DMF (20 ml), the respect-
ive amine (10 mmol) was added. Then, the mixture was refluxed
at 90 C for 12 h and poured into ice/water (50 ml). The separated
solid was filtered off then washed with water and hexane. The
products were purified by silica gel column chromatography using
DCM/MeOH to furnish the pure target compounds 6ao.
4.1.6.1. 2-(4-chlorophenyl)-6,7-dimethoxy-4(3-(4-methylpiperazin-
1-yl)propoxy)quinoline (6a). White solid, Yield 71%, m.p.
140142 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.15 (p, 2H, CH
2
,
J¼6.8 Hz), 2.29 (s, 3H, CH
3
-N), 2.362.66 (br s, 8H, piperazinyl
4CH
2
), 2.62 (t, 2H, CH
2
-N, J¼7.3 Hz), 4.01 (s, 3H, OCH
3
), 4.02 (s, 3H,
OCH
3
), 4.31 (t, 2H, CH
2
-O, J¼6.3 Hz), 7.03 (s, 1H, vinyl CH), 7.37 (s,
1H, phenyl CH), 7.40 (s, 1H, phenyl CH), 7.44 (d, 2H, chlorophenyl
2CH, J¼8.6 Hz), 7.99 (d, 2H, chlorophenyl 2CH, J¼8.6 Hz);
13
C
NMR (100 MHz, CDCl
3
)d(ppm): 26.59, 46.02, 53.31, 55.11, 56.04,
56.11, 66.65, 97.38, 99.68, 108.23, 114.93, 128.55, 128.82, 134.90,
139.00, 146.18, 149.07, 152.72, 155.59, 161.08; HRESIMS (m/z):
[M þH]
þ
Calcd for C
25
H
31
ClN
3
O
3
, 456.20485; found, 456.20474;
HPLC purity: 97.65%.
4.1.6.2. N-(3-((2(4-chlorophenyl)-6,7-dimethoxyquinolin-4-yl)oxy)-
propyl)cyclohexanamine (6b). Grey solid, Yield 80%, m.p.
118120 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.021.13 (m, 2H,
cyclohexyl 2CHH0), 1.141.19 (m, 1H, cyclohexyl CHH0), 1.201.30
(m, 2H, cyclohexyl 2CHH0), 1.44 (br s, 1H, NH), 1.591.63 (m, 1H,
cyclohexyl CHH0), 1.701.74 (m, 2H, cyclohexyl 2CHH0), 1.891.92
(m, 2H, cyclohexyl 2CHH0), 2.14 (p, 2H, CH
2
,J¼6.5 Hz), 2.432.50
(m, 1H, cyclohexyl CH-NH), 2.93 (t, 2H, CH
2
-NH, J¼6.9 Hz), 4.02 (s,
3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.35 (t, 2H, CH
2
-O, J¼6.1 Hz), 7.06
(s, 1H, vinyl CH), 7.39 (s, 1H, phenyl CH), 7.41 (s, 1H, phenyl CH),
7.45 (d, 2H, chlorophenyl 2CH, J¼8.6 Hz), 8 (d, 2H, chlorophenyl
2CH, J¼8.6 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 25.06, 26.14,
362 M. M. ELBADAWI ET AL.
30.00, 33.68, 43.90, 56.05, 56.12, 56.91, 66.94, 97.42, .99.67, 108.23,
114.94, 128.55, 128.82, 134.90, 138.98, 146.18, 149.07, 152.71,
155.61, 161.07; HRESIMS (m/z): [M þH]
þ
Calcd for C
26
H
32
ClN
2
O
3
,
455.20960; found, 455.20932; HPLC purity: 98.81%.
4.1.6.3. N-(3-((2(4-chlorophenyl)-6,7-dimethoxyquinolin-4-yl)oxy)-
propyl)-1-methylpiperidin-4-amine (6c). White solid, Yield 70%,
m.p. 124126 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.351.45 (m,
3H, piperidinyl 2CHH0, NH), 1.89 (d, 2H, piperidinyl 2CHH0,
J¼12.6 Hz), 1.97 (t, 2H, piperidinyl 2CHH0,J¼11.7 Hz), 2.14 (p, 2H,
CH
2
,J¼6.5 Hz), 2.25 (s, 3H, N-CH
3
), 2.432.51 (m, 1H, piperidinyl
CH-NH), 2.80 (d, 2H, piperidinyl 2CHH0,J¼11.7 Hz), 2.92 (t, 2H,
CH
2
-NH, J¼6.9 Hz), 4.01 (s, 3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.35 (t,
2H, CH
2
-O, J¼6.1 Hz), 7.05 (s, 1H, vinyl CH), 7.37 (s, 1H, phenyl
CH), 7.41 (s, 1H, phenyl CH), 7.44 (d, 2H, chlorophenyl 2CH,
J¼8.6 Hz), 7.99 (d, 2H, chlorophenyl 2CH, J¼8.6 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 29.96, 32.91, 43.73, 46.23, 54.50, 54.64,
56.06, 56.12, 66.83, 97.39, 99.64, 108.25, 114.92, 128.54, 128.83,
134.91, 138.97, 146.19, 149.08, 152.72, 155.60, 161.05; HRESIMS (m/
z): [M þH]
þ
Calcd for C
26
H
333
ClN
3
O
3
, 470.22050; found, 470.21988;
HPLC purity: 96.18%.
4.1.6.4. 3-((2(4-chlorophenyl)-6,7-dimethoxyquinolin-4-yl)oxy)-N-
((tetrahydrofuran-2-yl)methy- l)propan-1-amine (6d). White solid,
Yield 74%, m.p. 108110 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm):
1.481.57 (m, 1H, furyl CHH0), 1.66 (s, 1H, NH), 1.831.92 (m, 2H,
furyl CH
2
), 1.932 (m, 1H, furyl CHH0), 2.16 (p, 2H, CH
2
,J¼6.6 Hz),
2.67 (dd, 1H, furfuryl CHH0-NH, J¼8, 12 Hz) , 2.75 (dd, 1H, furfuryl
CHH0-NH, J¼3.6, 12 Hz) , 2.92 (t, 2H, CH
2
-NH, J¼6.9 Hz), 3.703.75
(m, 1H, furyl CHH0-O), 3.803.85 (m, 1H, furyl CHH0-O), 4 (p, 1H,
furyl CH-O, J¼3.6 Hz), 4.02 (s, 3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.36
(t, 2H, CH
2
-O, J¼6.2 Hz), 7.06 (s, 1H, vinyl CH), 7.39 (s, 1H, phenyl
CH), 7.41 (s, 1H, phenyl CH), 7.44 (d, 2H, chlorophenyl 2CH,
J¼8.6 Hz), 8 (d, 2H, chlorophenyl 2CH, J¼8.6 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 25.78, 29.32, 29.67, 46.99, 54.64, 56.08,
66.80, 67.95, 78.31, 97.41, 99.80, 108.25, 114.97, 128.55, 128.80,
134.88, 139.02, 146.20, 149.09, 152.73, 155.58, 161.12; HRESIMS (m/
z): [M þH]
þ
Calcd for C
25
H
30
ClN
2
O
4
, 457.18886; found, 457.18936;
HPLC purity: 97.34%.
4.1.6.5. 4-(3-(1H-imidazol-1-yl)propoxy)-2(4-chlorophenyl)-6,7-
dimethoxyquinoline (6e). White solid, Yield 75%, m.p. 209211 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.43 (p, 2H, CH
2
,J¼6.2 Hz),
4.03 (s, 3H, OCH
3
), 4.04 (s, 3H, OCH
3
), 4.22 (t, 2H, CH
2
-N,
J¼5.8 Hz), 4.28 (t, 2H, CH
2
-O, J¼6.6 Hz), 6.94 (s, 1H, imidazole
CH), 6.96 (s, 1H, vinyl CH), 7.07 (s, 1H, imidazole CH), 7.33 (s, 1H,
phenyl CH), 7.43 (s, 1H, phenyl CH), 7.44 (d, 2H, chlorophenyl 2CH,
J¼8.5 Hz), 7.50 (s, 1H, imidazole CH), 7.96 (d, 2H, chlorophenyl
2CH, J¼8.5 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 30.51, 43.59,
56.12, 64.48, 97.30, 99.33, 108.44, 114.67, 118.87, 128.51, 128.85,
130.03, 135.05, 137.23, 138.73, 146.34, 149.36, 152.94, 155.55,
160.43; HRESIMS (m/z): [M þH]
þ
Calcd for C
23
H
23
ClN
3
O
3
,
424.14225; found, 424.14264; HPLC purity: 99.50%.
4.1.6.6. 6,7-dimethoxy-4(3-(4-methylpiperazin-1-yl)propoxy)-2(4-
(trifluoromethyl)phenyl)quin-oline (6f). White solid, Yield 71%, m.p.
8486 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.17 (p, 2H, CH
2
,
J¼6.8 Hz), 2.29 (s, 3H, CH
3
-N), 2.362.71 (br s, 8H, piperazinyl
4CH
2
), 2.63 (t, 2H, CH
2
-N, J¼7.3 Hz), 4.02 (s, 3H, OCH
3
), 4.03 (s, 3H,
OCH
3
), 4.33 (t, 2H, CH
2
-O, J¼6.3 Hz), 7.09 (s, 1H, vinyl CH), 7.39 (s,
1H, phenyl CH), 7.43 (s, 1H, phenyl CH), 7.73 (d, 2H, CF
3
-phenyl
2CH, J¼8.2 Hz), 8.16 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 26.59, 46.03, 53.34, 55.12, 56.07, 56.13,
66.72, 97.71, 99.64, 108.28, 115.18, 124.26 (CF
3
,q,J¼271.7 Hz),
125.59 (CH-C-CF
3
,q,J¼3.9 Hz), 127.59, 130.59 (CH-C-CF
3
,q,
J¼32.4 Hz), 143.94, 146.24, 149.32, 152.84, 155.25, 161.18;
19
F
NMR (376.46 MHz, CDCl
3
)d(ppm): 62.47 (s); HRESIMS (m/z):
[M þH]
þ
Calcd for C
26
H
31
F
3
N
3
O
3
, 490.23120; found, 490.23087;
HPLC purity: 98.93%.
4.1.6.7. N-(3-((6,7-dimethoxy-2(4-(trifluoromethyl)phenyl)quinolin-
4-yl)oxy)propyl)cyclohexan- amine (6g). Grey solid, Yield 75%, m.p.
131133 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.021.12 (m, 2H,
cyclohexyl 2CHH0), 1.131.19 (m, 1H, cyclohexyl CHH0), 1.201.30
(m, 2H, cyclohexyl 2CHH0), 1.37 (br s, 1H, NH), 1.591.63 (m, 1H,
cyclohexyl CHH0), 1.701.74 (m, 2H, cyclohexyl 2CHH0), 1.891.92
(m, 2H, cyclohexyl 2CHH0), 2.15 (p, 2H, CH
2
,J¼6.5 Hz), 2.432.50
(m, 1H, cyclohexyl CH-NH), 2.93 (t, 2H, CH
2
-NH, J¼6.9 Hz), 4.03 (s,
3H, OCH
3
), 4.04 (s, 3H, OCH
3
), 4.37 (t, 2H, CH
2
-O, J¼6.1 Hz), 7.11
(s, 1H, vinyl CH), 7.40 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl CH),
7.73 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz), 8.16 (d, 2H, CF
3
-phenyl
2CH, J¼8.2 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 25.05, 26.14,
30.03, 33.71, 43.87, 56.07, 56.13, 56.90, 67.01, 97.73, 99.64, 108.30,
115.19, 124.26 (CF
3
,q,J¼272 Hz), 125.59 (CH-C-CF
3
,q,J¼3.7 Hz),
127.57, 130.62 (CH-C-CF
3
,q,J¼33.9 Hz), 143.92, 146.24, 149.33,
152.84, 155.25, 161.17;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm):
62.47 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
27
H
32
F
3
N
2
O
3
,
489.23595; found489.23578; HPLC purity: 99.37%.
4.1.6.8. N-(3-((6,7-dimethoxy-2(4-(trifluoromethyl)phenyl)quinolin-
4-yl)oxy)propyl)-1-methyl p- iperidin-4-amine (6h). White solid,
Yield 78%, m.p. 137139 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm):
1.361.45 (m, 3H, piperidinyl 2CHH0, NH), 1.89 (d, 2H, piperidinyl
2CHH0,J¼12.5 Hz), 1.97 (t, 2H, piperidinyl 2CHH0,J¼11.7 Hz), 2.14
(p, 2H, CH
2
,J¼6.5 Hz), 2.25 (s, 3H, N-CH
3
), 2.432.51 (m, 1H, piper-
idinyl CH-NH), 2.80 (d, 2H, piperidinyl 2CHH0,J¼11.7 Hz), 2.92 (t,
2H, CH
2
-NH, J¼6.9 Hz), 4.02 (s, 3H, OCH
3
), 4.04 (s, 3H, OCH
3
), 4.37
(t, 2H, CH
2
-O, J¼6.1 Hz), 7.10 (s, 1H, vinyl CH), 7.39 (s, 1H, phenyl
CH), 7.43 (s, 1H, phenyl CH), 7.73 (d, 2H, CF
3
-phenyl 2CH,
J¼8.2 Hz), 8.16 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 29.95, 32.89, 43.68, 46.21, 54.50, 54.63,
56.08, 56.14, 66.89, 97.71, 99.61, 108.31, 115.17, 124.27 (CF
3
,q,
J¼272.6 Hz), 125.60 (CH-C-CF
3
,q,J¼3.9 Hz), 127.57, 130.64 (CH-C-
CF
3
,q,J¼32.7Hz), 143.90, 146.25, 149.34, 152.85, 155.26, 161.15;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm): 62.47 (s); HRESIMS (m/z):
[M þH]
þ
Calcd for C
27
H
33
F
3
N
3
O
3
, 504.24685; found, 504.24692;
HPLC purity: 99.75%.
4.1.6.9. 3-((6,7-dimethoxy-2(4-(trifluoromethyl)phenyl)quinolin-4-
yl)oxy)-N-((tetrahydrofuran-2-yl)methyl)propan-1-amine (6i). White
solid, Yield 76%, m.p. 105107 C;
1
H NMR (400 MHz, CDCl
3
)d
(ppm): 1.491.57 (m, 1H, furyl CHH0), 1.69 (s, 1H, NH), 1.831.92 (m,
2H, furyl CH
2
), 1.932 (m, 1H, furyl CHH0), 2.18 (p, 2H, CH
2
,
J¼6.6 Hz), 2.68 (dd, 1H, furfuryl CHH0-NH, J¼8, 12 Hz) , 2.75 (dd,
1H, furfuryl CHH0-NH, J¼3.5, 12 Hz), 2.93 (t, 2H, CH
2
-NH,
J¼6.9 Hz), 3.703.75 (m, 1H, furyl CHH0-O), 3.803.86 (m, 1H, furyl
CHH0-O), 4 (p, 1H, furyl CH-O, J¼3.5 Hz), 4.03 (s, 3H, OCH
3
), 4.04
(s, 3H, OCH
3
), 4.38 (t, 2H, CH
2
-O, J¼6.2 Hz), 7.11 (s, 1H, vinyl CH),
7.41 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl CH), 7.43 (d, 2H, CF
3
-
phenyl 2CH, J¼8.2 Hz), 8.16 (d, 2H, chlorophenyl 2CH, J¼8.2 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 25.78, 29.32, 29.64, 47.00,
54.67, 56.11, 56.13, 66.87, 67.97, 78.28, 97.74, 99.72, 108.26,
115.20, 124.28 (CF
3
,q,J¼272 Hz), 125.58 (CH-C-CF
3
,q,J¼3.8 Hz),
127.58, 130.59 (CH-C-CF
3
,q,J¼32.3 Hz), 143.92, 146.23, 149.31,
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 363
152.82, 155.24, 161.20;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm):
62.46 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
26
H
30
F
3
N
2
O
4
,
491.21522; found, 491.21533; HPLC purity: 99.63%.
4.1.6.10. 4-(3-(1H-imidazol-1-yl)propoxy)-6,7-dimethoxy-2(4-(tri-
fluoromethyl)phenyl)quinoline (6j). White solid, Yield 88%, m.p.
217219 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.45 (p, 2H, CH
2
,
J¼6.2 Hz), 4.05 (s, 3H, OCH
3
), 4.06 (s, 3H, OCH
3
), 4.24 (t, 2H, CH
2
-
N, J¼5.8 Hz), 4.29 (t, 2H, CH
2
-O, J¼6.6 Hz), 6.94 (s, 1H, imidazole
CH), 7.01 (s, 1H, vinyl CH), 7.08 (s, 1H, imidazole CH), 7.35 (s, 1H,
phenyl CH), 7.46 (s, 1H, phenyl CH), 7.51 (s, 1H, imidazole CH),
7.73 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz), 8.13 (d, 2H, CF
3
-phenyl
2CH, J¼8.2 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 30.49, 43.58,
56.15, 56.18, 64.54, 97.63, 99.24, 108.47, 114.90, 118.88, 124.23
(CF
3
,q,J¼272 Hz), 125.63 (CH-C-CF
3
,q,J¼3.7 Hz), 127.56, 130.05,
130.72 (CH-C-CF
3
,q,J¼32.5 Hz), 137.25, 143.64, 146.38, 149.59,
153.03, 155.22, 160.51;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm):
62.48 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
24
H
23
F
3
N
3
O
3
,
458.16860; found, 458.16879; HPLC purity: 99.78%.
4.1.6.11. 6,7-dimethoxy-4(3-(4-methylpiperazin-1-yl)propoxy)-2-(p-
tolyl)quinoline (6k). White solid, Yield 70%, m.p. 128130 C;
1
H
NMR (400 MHz, CDCl
3
)d(ppm): 2.15 (p, 2H, CH
2
,J¼6.8 Hz), 2.29 (s ,
3H, CH
3
-N), 2.41 (s, 3H, tolyl CH
3
), 2.412.64 (br s, 8H, piperazinyl
4CH
2
), 2.62 (t, 2H, CH
2
-N, J¼7.3 Hz), 4.01 (s, 3H, OCH
3
), 4.02 (s, 3H,
OCH
3
), 4.31 (t, 2H, CH
2
-O, J¼6.3Hz), 7.07 (s, 1H, vinyl CH), 7.44 (d,
2H, tolyl 2CH, J¼8Hz), 7.38 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl
CH), 7.94 (d, 2H, tolyl 2CH, J¼8Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 21.29, 26.62, 46.03, 53.33, 55.12, 55.17, 56.02, 56.09, 66.56,
97.58, 99.72, 108.30, 114.76, 127.16, 129.39, 137.79, 138.77, 146.20,
148.77, 152.52, 157.01, 160.91; HRESIMS (m/z): [M þH]
þ
Calcd for
C
26
H
34
N
3
O
3
, 436.25947; found, 436.25943; HPLC purity: 96.05%.
4.1.6.12. N-(3-((6,7-dimethoxy-2-(p-tolyl)quinolin-4-yl)oxy)propyl)-
cyclohexanamine (6l). Buff solid, Yield 73%, m.p. 126128 C;
1
H
NMR (400 MHz, CDCl
3
)d(ppm): 1.031.14 (m, 2H, cyclohexyl
2CHH0), 1.151.21 (m, 1H, cyclohexyl CHH0), 1.231.30 (m, 2H,
cyclohexyl 2CHH0), 1.591.63 (m, 2H, cyclohexyl CHH0, NH),
1.701.75 (m, 2H, cyclohexyl 2CHH0), 1.891.93 (m, 2H, cyclohexyl
2CHH0), 2.15 (p, 2H, CH
2
,J¼6.6 Hz), 2.41 (s, 3H, tolyl CH
3
),
2.442.51 (m, 1H, cyclohexyl CH-NH), 2.93 (t, 2H, CH
2
-NH, J¼7 Hz),
4.01 (s, 3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.34 (t, 2H, CH
2
-O,
J¼6.1 Hz), 7.08 (s, 1H, vinyl CH), 7.29 (d, 2H, tolyl 2CH, J¼8 Hz),
7.39 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl CH), 7.95 (d, 2H, tolyl
2CH, J¼8 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 21.29, 25.05,
26.13, 29.96, 33.62, 43.93, 56.03, 56.09, 56.91, 66.84, 97.60, 99.71,
108.32, 114.77, 127.15, 129.40, 137.77, 138.78, 146.21, 148.79,
152.52, 157.01, 160.88; HRESIMS (m/z): [M þH]
þ
Calcd for
C
27
H
35
N
2
O
3
, 435.26422; found, 435.26422; HPLC purity: 97.90%.
4.1.6.13. N-(3-((6,7-dimethoxy-2-(p-tolyl)quinolin-4-yl)oxy)propyl)-
1-methylpiperidin-4-amine (6m). White solid, Yield 76%, m.p.
6668 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.351.45 (m, 3H,
piperidinyl 2CHH0, NH), 1.89 (d, 2H, piperidinyl 2CHH0,J¼12.5 Hz),
1.96 (t, 2H, piperidinyl 2CHH0,J¼11.8 Hz), 2.13 (p, 2H, CH
2
,
J¼6.5 Hz), 2.24 (s, 3H, N-CH
3
), 2.41 (s, 3H, tolyl CH
3
), 2.432.50 (m,
1H, piperidinyl CH-NH), 2.80 (d, 2H, piperidinyl 2CHH0,J¼11.8 Hz),
2.91 (t, 2H, CH
2
-NH, J¼6.9 Hz), 4.01 (s, 3H, OCH
3
), 4.02 (s, 3H,
OCH
3
), 4.34 (t, 2H, CH
2
-O, J¼6.1 Hz), 7.08 (s, 1H, vinyl CH), 7.28 (d,
2H, tolyl 2CH, J¼8 Hz), 7.37 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl
CH), 7.94 (d, 2H, tolyl 2CH, J¼8 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 21.29, 29.97, 32.90, 43.79, 46.22, 54.49, 54.64, 56.03, 56.09,
66.74, 97.58, 99.68, 108.33, 114.75, 127.14, 129.40, 137.76, 138.79,
146.21, 148.79, 152.53, 157.00, 160.87; HRESIMS (m/z): [M þH]
þ
Calcd for C
27
H
36
N
3
O
3
, 450.27512; found, 450.27481; HPLC pur-
ity: 95.52%.
4.1.6.14. 3-((6,7-dimethoxy-2-(p-tolyl)quinolin-4-yl)oxy)-N-((tetra-
hydrofuran-2-yl)methyl)propa- n-1-amine (6n). Yellow solid, Yield
85%, m.p. 6062 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.481.57
(m, 1H, furyl CHH0), 1.832.00 (m, 4H, furyl CH
2
, furyl CHH0, NH),
2.16 (p, 2H, CH
2
,J¼6.5 Hz), 2.41 (s, 3H, tolyl CH
3
), 2.67 (dd, 1H,
furfuryl CHH0-NH, J¼8, 12 Hz), 2.74 (dd, 1H, furfuryl CHH0-NH,
J¼3.6, 12 Hz), 2.92 (t, 2H, CH
2
-NH, J¼6.8 Hz), 3.693.75 (m, 1H,
furyl CHH0-O), 3.793.85 (m, 1H, furyl CHH0-O), 4 (p, 1H, furyl CH-O,
J¼3.6 Hz), 4.02 (s, 3H, OCH
3
), 4.03 (s, 3H, OCH
3
), 4.35 (t, 2H, CH
2
-
O, J¼6.2 Hz), 7.08 (s, 1H, vinyl CH), 7.29 (d, 2H, tolyl 2CH,
J¼8 Hz), 7.39 (s, 1H, phenyl CH), 7.43 (s, 1H, phenyl CH), 7.94 (d,
2H, tolyl 2CH, J¼8 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 21.28,
25.77, 29.33, 29.61, 47.06, 54.61, 56.06, 56.08, 66.70, 67.95, 78.23,
97.64, 99.80, 108.22, 114.78, 127.18, 129.39, 137.76, 138.78, 146.16,
148.78, 152.53, 157.03, 160.93; HRESIMS (m/z): [M þH]
þ
Calcd for
C
26
H
33
N
2
O
4
, 437.24348; found, 437.24353; HPLC purity: 97.50%.
4.1.6.15. 4-(3-(1H-imidazol-1-yl)propoxy)-6,7-dimethoxy-2-(p-tolyl)-
quinoline (6o). White solid, Yield 83%, m.p. 203205 C;
1
H NMR
(400 MHz, CDCl
3
)d(ppm): 2.41 (s, 3H, tolyl CH
3
), 2.42 (p, 2H, CH
2
,
J¼6.3 Hz), 4.03 (s, 6H, 2CH
3
O), 4.22 (t, 2H, CH
2
-N, J¼5.8 Hz), 4.27
(t, 2H, CH
2
-O, J¼6.7 Hz), 6.93 (s, 1H, imidazole CH), 6.99 (s, 1H,
vinyl CH), 7.07 (s, 1H, imidazole CH), 7.28 (d, 2H, tolyl 2CH,
J¼8.1 Hz), 7.34 (s, 1H, phenyl CH), 7.45 (s, 1H, phenyl CH), 7.51 (s,
1H, imidazole CH), 7.92 (d, 2H, tolyl 2CH, J¼8.1 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 21.29, 30.55, 43.62, 56.10, 56.13, 64.37,
97.50, 99.35, 108.48, 114.48, 118.92, 127.12, 129.44, 129.97, 137.22,
137.51, 138.96, 146.34, 149.03, 152.71, 156.97, 160.25; HRESIMS (m/
z): [M þH]
þ
Calcd for C
24
H
26
N
3
O
3
, 404.19687; found, 404.19724;
HPLC purity: 99.42%.
4.1.7. Synthesis of 2-(4-bromophenyl)-6,7-dimethoxy-4-(3-(4-meth-
ylpiperazin-1-yl)propoxy)qu-inoline (7)
The bromo analog of 4-propoxy-N-methylpiperazine-2-arylquino-
line 7has been prepared using the same synthetic procedure as
6aoutilising p-bromobenzoyl chloride.
White solid, Yield 77%, m.p. 148150 C;
1
H NMR (400 MHz,
CDCl
3
)d(ppm): 2.15 (p, 2H, CH
2
,J¼6.8 Hz), 2.29 (s, 3H, CH
3
-N),
2.362.66 (br s, 8H, piperazinyl 4CH
2
), 2.62 (t, 2H, CH
2
-N,
J¼7.3 Hz), 4.01 (s, 3H, OCH
3
), 4.02 (s, 3H, OCH
3
), 4.31 (t, 2H, CH
2
-
O, J¼6.3 Hz), 7.03 (s, 1H, vinyl CH), 7.37 (s, 1H, phenyl CH), 7.41 (s,
1H, phenyl CH), 7.60 (d, 2H, bromophenyl 2CH, J¼8.6 Hz), 7.92 (d,
2H, bromophenyl 2CH, J¼8.6 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 26.57, 45.96, 53.24, 55.07, 56.04, 56.10, 66.65, 97.34, 99.71,
108.23, 114.97, 123.23, 128.85, 131.77, 139.45, 146.20, 149.11,
152.76, 155.62, 161.10; HRESIMS (m/z): [M þH]
þ
Calcd for
C
25
H
31
BrN
3
O
3
, 500.15433; found, 500.15466.
4.1.8. General procedure for synthesis of heterocyclic analogs of
the bromo derivative (8a,b)
The bromo derivative 7(125 mg, 0.25 mmol) was taken with 2-fur-
ylboronic acid or 2-thienylboronic acid (0.5 mmol) and Pd(PPh
3
)
4
(0.05 equivalent, 15 mg), then dioxane (5 ml) and 2 M Na
2
CO
3
(0.3 ml) were added to the mixture under N
2
atmosphere. The
reaction mixture was refluxed under N
2
at 90 C for 16 h. Then,
the reaction mixture was poured into ice/water (50 ml), the
364 M. M. ELBADAWI ET AL.
aqueous layer was extracted with ethyl acetate (50 3) and the
organic layers were washed with water and brine. After evapor-
ation of the organic solvent under vacuum, the residue was puri-
fied by silica gel column chromatography using DCM/MeOH to
furnish 8a,b in pure form.
4.1.8.1. 2-(4-(furan-2-yl)phenyl)-6,7-dimethoxy-4-(3-(4-methylpiper-
azin-1-yl)propoxy)quinoline (8a). Yellow solid, Yield 70%, m.p.
135137 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.17 (p, 2H, CH
2
,
J¼6.8 Hz), 2.34 (s, 3H, CH
3
-N), 2.432.78 (br s, 8H, piperazinyl
4CH
2
), 2.66 (t, 2H, CH
2
-N, J¼7.3 Hz), 4.02 (s, 3H, OCH
3
), 4.04 (s, 3H,
OCH
3
), 4.33 (t, 2H, CH
2
-O, J¼6.3 Hz), 6.50 (dd, 1H, furyl CH, J¼1.8,
3.4 Hz), 6.73 (dd, 1H, furyl CH, J¼0.5, 3.4 Hz), 7.11 (s, 1H, vinyl CH),
7.38 (s, 1H, phenyl CH), 7.44 (s, 1H, phenyl CH), 7.50 (dd, 1H, furyl
CH-O, J¼0.5, 1.8 Hz), 7.79 (d, 2H, 2-phenyl 2CH, J¼8.5 Hz), 8.09
(d, 2H, 2-phenyl 2CH, J¼8.5 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 26.53, 45.73, 52.86, 54.91, 55.02, 56.07, 56.12, 66.51, 97.49,
99.69, 105.63, 108.28, 111.83, 114.89, 124.02, 127.58, 131.21,
139.24, 142.35, 146.23, 148.95, 152.65, 153.71, 156.27, 160.95;
HRESIMS (m/z): [M þH]
þ
Calcd for C
29
H
34
N
3
O
4
, 488.25438; found,
488.25446; HPLC purity: 96.06%.
4.1.8.2. 6,7-dimethoxy-4(3-(4-methylpiperazin-1-yl)propoxy)-2(4-
(thiophen-2-yl)phenyl)quinol-ine (8b). Buff solid, Yield 72%, m.p.
155157 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.17 (p, 2H, CH
2
,
J¼6.8 Hz), 2.29 (s, 3H, CH
3
-N), 2.342.70 (br s, 8H, piperazinyl
4CH
2
), 2.63 (t, 2H, CH
2
-N, J¼7.3 Hz), 4.02 (s, 3H, OCH
3
), 4.03 (s, 3H,
OCH
3
), 4.33 (t, 2H, CH
2
-O, J¼6.3 Hz), 7.09 (dd, 1H, thienyl CH,
J¼3.7, 5.1 Hz), 7.10 (s, 1H, vinyl CH), 7.30 (dd, 1H, thienyl CH,
J¼1.1, 5.1 Hz), 7.38 (dd, 1H, thienyl CH-S, J¼1.1, 3.7 Hz), 7.39 (s,
1H, phenyl CH), 7.44 (s, 1H, phenyl CH), 7.73 (d, 2H, 2-phenyl 2CH,
J¼8.4 Hz), 8.08 (d, 2H, 2-phenyl 2CH, J¼8.4 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 26.62, 46.05, 53.35, 55.13, 55.17, 56.04,
56.12, 66.62, 97.49, 99.72, 108.30, 114.94, 123.39, 125.12, 126.09,
127.76, 128.13, 134.80, 139.52, 144.01, 146.25, 148.95, 152.64,
156.20, 160.99; HRESIMS (m/z): [M þH]
þ
Calcd for C
29
H
34
N
3
O
3
S,
504.23154; found, 504.23141; HPLC purity: 98.96%.
4.1.9. Synthesis of 4-(3-chloropropoxy)-2-(4-(trifluoromethyl)phe-
nyl)quinoline (9)
The demethoxylated key intermediate 9has been synthesised
using the same synthetic procedure for 5acstarting from 2-
aminoacetophenone.
White solid, Yield 76%, m.p. 98100 C;
1
H NMR (400 MHz, CDCl
3
)
d(ppm): 2.45 (p, 2H, CH
2
,J¼6Hz),2.87(t,2H,CH
2
-N, J¼6.2 Hz),
4.46 (t, 2H, CH
2
-O, J¼5.8 Hz), 7.20 (s, 1H, vinyl CH), 7.52 (ddd, 1H,
phenyl CH, J¼1.2, 6.9, 8.3 Hz), 7.74 (ddd, 1H, phenyl CH, J¼1.3, 6.9,
8.4 Hz), 7.77 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz), 8.11 (d, 2H, phenyl
CH, J¼8.4Hz),8.19(dd,1H,phenylCH,J¼1.3, 8.3 Hz), 8.22 (d, 2H,
CF
3
-phenyl 2CH, J¼8.2 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm):
31.94, 41.23, 64.86, 98.50, 121.56, 124.20 (CF
3
,q,J¼272 Hz), 125.67
(CH-C-CF
3
,q,J¼3.7 Hz), 125.96, 127.87, 129.42, 130.31, 131.08 (CH-C-
CF
3
,q,J¼32.4 Hz), 143.56, 149.23, 157.12, 162.07;
19
FNMR
(376.46 MHz, CDCl
3
)d(ppm): 62.53 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
19
H
16
ClF
3
NO, 366.08670; found, 366.08725.
4.1.10. Synthesis of the target demethoxylated 4-propoxy-2-aryl-
quinolines (10a,b)
The demethoxylated 4-propoxy-2-arylquinolines 10a,b were pre-
pared according to the general synthetic procedure for 6ao
using the respective key intermediate 9.
4.1.10.1. 4-(3-(4-methylpiperazin-1-yl)propoxy)-2-(4-(trifluorome-
thyl)phenyl)quinoline (10a). White solid, Yield 87%, m.p.
110112 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.16 (p, 2H, CH
2
,
J¼6.7 Hz), 2.29 (s, 3H, CH
3
-N), 2.372.71 (br s, 8H, piperazinyl
4CH
2
), 2.64 (t, 2H, CH
2
-N, J¼7.2 Hz), 4.34 (t, 2H, CH
2
-O, J¼6.2 Hz),
7.16 (s, 1H, vinyl CH), 7.50 (ddd, 1H, phenyl CH, J¼1.1, 6.9, 8.2 Hz),
7.72 (ddd, 1H, phenyl CH, J¼1.5 6.9, 8.3 Hz), 7.75 (d, 2H, CF
3
-phe-
nyl 2CH, J¼8.2 Hz), 8.09 (d, 2H, phenyl CH, J¼8.3 Hz), 8.2 (m, 3H,
phenyl CH, CF
3
-phenyl 2CH);
13
C NMR (100 MHz, CDCl
3
)d(ppm):
26.54, 46.04, 53.30, 55.00, 55.13, 66.79, 98.49, 120.63, 121.74,
124.21 (CF
3
,q,J¼272 Hz), 125.63 (CH-C-CF
3
,q,J¼3.8 Hz), 125.82
127.89, 129.32, 130.21, 130.99 (CH-C-CF
3
,q,J¼32.6 Hz), 143.72,
149.19, 157.14, 162.43;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm):
62.53 (s); HRESIMS (m/z): [M þNa]
þ
Calcd for C
21
H
33
ClF
3
NONa,
430.20950; found, 430.20993; HPLC purity: 98.63%.
4.1.10.2. N-(3-((2-(4-(trifluoromethyl)phenyl)quinolin-4-yl)oxy)pro-
pyl)cyclohexanamine (10b). Grey solid, Yield 78%, m.p. 6870 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 1.031.13 (m, 2H, cyclohexyl
2CHH0), 1.141.19 (m, 1H, cyclohexyl CHH0), 1.201.31 (m, 3H,
cyclohexyl 2CHH0, NH), 1.601.63 (m, 1H, cyclohexyl CHH0),
1.711.75 (m, 2H, cyclohexyl 2CHH0), 1.91 (d, 2H, cyclohexyl 2CHH0,
J¼10.2 Hz), 2.15 (p, 2H, CH
2
,J¼6.5 Hz), 2.432.50 (m, 1H, cyclo-
hexyl CH-NH), 2.94 (t, 2H, CH
2
-NH, J¼6.9 Hz), 4.38 (t, 2H, CH
2
-O,
J¼6.1 Hz), 7.18 (s, 1H, vinyl CH), 7.51 (ddd, 1H, phenyl CH, J¼1.1,
7, 8.1 Hz), 7.72 (ddd, 1H, phenyl CH, J¼1.4 7, 8.3 Hz), 7.75 (d, 2H,
CF
3
-phenyl 2CH, J¼8.7 Hz), 8.09 (d, 2H, phenyl CH, J¼8.3 Hz),
8.21 (d, 3H, phenyl CH, CF
3
-phenyl 2CH, J¼8.1 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 25.08, 26.16, 30.05, 33.71, 43.77, 56.94,
67.04, 98.51, 120.64, 121.74, 124.25 (CF
3
,q,J¼271.7 Hz), 125.64
(CH-C-CF
3
,q,J¼3.7 Hz), 125.82, 127.88, 129.33, 130.20, 130.99
(CH-C-CF
3
,q,J¼32.4Hz), 143.70, 149.20, 157.15, 162.42;
19
F NMR
(376.46 MHz, CDCl
3
)d(ppm): 62.53 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
25
H
28
F
3
N
2
O, 429.21482; found, 429.21420; HPLC pur-
ity: 99.22%.
4.1.11. Synthesis of 1,3-dioxoloarylquinolines key intermedi-
ates (11a,b)
Starting from 60-amino-30,40-(methylenedioxy)acetophenone and
the respective p-substituted benzoyl chloride, the key intermedi-
ates 11a,b were prepared according to the synthetic route
for 5ac.
4.1.11.1. 6-(4-chlorophenyl)-8(3-chloropropoxy)-[1,3]dioxolo[4,5-
g]quinoline (11a). White solid, Yield 90%, m.p. 186188 C;
1
H
NMR (400 MHz, CDCl
3
)d(ppm): 2.40 (p, 2H, CH
2
,J¼6 Hz), 3.83 (t,
2H, CH
2
Cl, J¼6.2 Hz), 4.39 (t, 2H, CH
2
-O, J¼5.8 Hz), 6.09 (s, 2H,
dioxolo CH
2
), 7.05 (s, 1H, vinyl CH), 7.37 (s, 1H, phenyl CH), 7.39 (s,
1H, phenyl CH), 7.45 (d, 2H, chlorophenyl 2CH, J¼8.6 Hz), 8 (d,
2H, chlorophenyl 2CH, J¼8.6 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 31.99, 41.27, 64.68, 97.50, 101.68, 106.01, 116.23, 128.53,
128.84, 135.06, 138.63, 147.30, 147.48, 151.04, 155.48, 161.15;
HRESIMS (m/z): [M þH]
þ
Calcd for C
19
H
16
Cl
2
NO
3
, 376.05018; found,
376.05045.
4.1.11.2. 8-(3-chloropropoxy)-6-(4-(trifluoromethyl)phenyl)-[1,3]
dioxolo[4,5-g]quinoline (11b). White solid, Yield 93%, m.p.
145147 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.41 (p, 2H, CH
2
,
J¼6 Hz), 3.84 (t, 2H, CH
2
Cl, J¼6.2 Hz), 4.41 (t, 2H, CH
2
-O,
J¼5.8 Hz), 6.10 (s, 2H, dioxolo CH
2
), 7.10 (s, 1H, vinyl CH), 7.39 (s,
1H, phenyl CH), 7.40 (s, 1H, phenyl CH), 7.73 (d, 2H, CF
3
-phenyl
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY 365
2CH, J¼8.1 Hz), 8.16 (d, 2H, CF
3
-phenyl 2CH, J¼8.1 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 31.96, 41.24, 64.74, 97.50, 97.83, 101.75,
106.09, 116.50, 124.25 (CF
3
,q,J¼271.8 Hz), 125.61 (CH-C-CF
3
,q,
J¼3.7 Hz), 127.56, 130.72 (CH-C-CF
3
,q,J¼32.4 Hz), 143.55, 147.54,
147.57, 151.16, 155.13, 161.25;
19
F NMR (376.46 MHz, CDCl
3
)d
(ppm): 62.50 (s); HRESIMS (m/z): [M þH]
þ
Calcd for
C
20
H
16
ClF
3
NO
3
, 410.07653; found, 410.07736.
4.1.12. Synthesis of the target propoxy derivatives of 1,3-dioxo-
loarylquinolines (12ad)
The target dioxolo derivatives 12adhave been synthesised utilis-
ing the synthetic procedures used for 6aousing imidazole or
morpholine with the appropriate key intermediate 11a,b.
4.1.12.1. 8-(3-(1H-imidazol-1-yl)propoxy)-6-(4-chlorophenyl)-[1,3]
dioxolo[4,5-g]quinoline (12a). White solid, Yield 77%, m.p.
146148 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.39 (p, 2H, CH
2
,
J¼6.2 Hz), 4.16 (t, 2H, CH
2
-N, J¼5.7 Hz), 4.28 (t, 2H, CH
2
-O,
J¼6.7 Hz), 6.10 (s, 2H, dioxolo CH
2
), 6.93 (s, 1H, imidazole CH),
6.94 (s, 1H, vinyl CH), 7.07 (s, 1H, imidazole CH), 7.38 (s, 1H, phenyl
CH), 7.39 (s, 1H, phenyl CH), 7.43 (d, 2H, chlorophenyl 2CH,
J¼8.7 Hz), 7.49 (s, 1H, imidazole CH), 7.95 (d, 2H, chlorophenyl
2CH, J¼8.7 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 30.54, 43.43,
64.18, 97.23, 97.46, 101.76, 106.13, 116.07, 118.90, 128.51, 128.85,
129.98, 135.12, 137.27, 138.49, 147.46, 147.53, 151.13, 155.48,
160.83; HRESIMS (m/z): [M þH]
þ
Calcd for C
22
H
19
ClN
3
O
3
,
408.11095; found, 408.11179; HPLC purity: 99.60%.
4.1.12.2. 6-(4-chlorophenyl)-8-(3-morpholinopropoxy)-[1,3]dioxolo
[4,5-g]quinoline (12b). White solid, Yield 72%, m.p. 153155 C;
1
H
NMR (400 MHz, CDCl
3
)d(ppm): 2.12 (p, 2H, CH
2
,J¼6.7 Hz), 2.49 (t,
4H, morpholinyl 2CH
2
,J¼4.6 Hz), 2.61 (t, 2H, CH
2
-N, J¼7.2 Hz),
3.73 (t, 4H, morpholinyl 2CH
2
,J¼4.6 Hz), 4.29 (t, 2H, CH
2
-O,
J¼6.2 Hz), 6.08 (s, 2H, dioxolo CH
2
), 7.03 (s, 1H, vinyl CH), 7.36 (s,
1H, phenyl CH), 7.42 (s, 1H, phenyl CH), 7.44 (d, 2H, chlorophenyl
2CH, J¼8.7 Hz), 7.99 (d, 2H, chlorophenyl 2CH, J¼8.7 Hz);
13
C
NMR (100 MHz, CDCl
3
)d(ppm): 26.27, 53.82, 55.47, 66.43, 66.98,
97.50, 97.66, 101.63, 105.97, 116.35, 128.53, 128.82, 135.00, 138.76,
147.21, 147.44, 150.97, 155.51, 161.49; HRESIMS (m/z): [M þH]
þ
Calcd for C
23
H
24
ClN
2
O
4
, 427.14191; found, 427.14221; HPLC pur-
ity: 98.94%.
4.1.12.3. 8-(3-(1H-imidazol-1-yl)propoxy)-6-(4-(trifluoromethyl)-
phenyl)-[1,3]dioxolo[4,5-g]qui-noline (12c). White solid, Yield 81%,
m.p. 125127 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.41 (p, 2H,
CH
2
,J¼6.2 Hz), 4.19 (t, 2H, CH
2
-N, J¼5.7 Hz), 4.29 (t, 2H, CH
2
-O,
J¼6.7 Hz), 6.12 (s, 2H, dioxolo CH
2
), 6.93 (s, 1H, imidazole CH), 7
(s, 1H, vinyl CH), 7.08 (s, 1H, imidazole CH), 7.41 (s, 2H, phenyl
2CH), 7.49 (s, 1H, imidazole CH), 7.72 (d, 2H, CF
3
-phenyl 2CH,
J¼8.2 Hz), 8.12 (d, 2H, CF
3
-phenyl 2CH, J¼8.2 Hz);
13
C NMR
(100 MHz, CDCl
3
)d(ppm): 30.52, 43.42, 64.26, 97.22, 97.79, 101.83,
106.22, 16.34, 118.88, 124.22 (CF
3
,q,J¼272.7 Hz), 125.61 (CH-C-
CF
3
,q,J¼3.7 Hz), 127.55, 130.01, 130.79 (CH-C-CF
3
,q,J¼33.2 Hz),
137.28, 143.41, 147.60, 147.73, 151.26, 155.15, 160.92;
19
F NMR
(376.46 MHz, CDCl
3
)d(ppm): 62.52 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
23
H
19
F
3
N
3
O
3
, 442.13730; found, 442.13754; HPLC pur-
ity: 99.35%.
4.1.12.4. 8-(3-morpholinopropoxy)-6-(4-(trifluoromethyl)phenyl)-
[1,3]dioxolo[4,5-g]quinoline (12d). White solid, Yield 76%, m.p.
138140 C;
1
H NMR (400 MHz, CDCl
3
)d(ppm): 2.14 (p, 2H, CH
2
,
J¼6.7 Hz), 2.50 (t, 4H, morpholinyl 2CH
2
,J¼4.4 Hz), 2.62 (t, 2H,
CH
2
-N, J¼7.2 Hz), 3.73 (t, 4H, morpholinyl 2CH
2
,J¼4.4 Hz), 4.32 (t,
2H, CH
2
-O, J¼6.2 Hz), 6.10 (s, 2H, dioxolo CH
2
), 7.08 (s, 1H, vinyl
CH), 7.39 (s, 1H, phenyl CH), 7.44 (s, 1H, phenyl CH), 7.73 (d, 2H,
CF
3
-phenyl 2CH, J¼8.2 Hz), 8.16 (d, 2H, CF
3
-phenyl 2CH,
J¼8.2 Hz);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 26.27, 53.82, 55.45,
66.51, 66.98, 97.65, 97.83, 101.70, 106.05, 116.62, 124.23 (CF
3
,q,
J¼272.3 Hz), 125.59 (CH-C-CF
3
,q,J¼3.9 Hz), 127.57, 130.70 (CH-C-
CF
3
,q,J¼32.2Hz), 143.70, 147.48, 147.51, 151.10, 155.18, 161.59;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm): 62.50 (s); HRESIMS (m/z):
[M þH]
þ
Calcd for C
24
H
24
F
3
N
2
O
4
, 461.16827; found, 461.16837;
HPLC purity: 99.62%.
4.1.13. Synthesis of 1-(2-amino-5-bromophenyl)ethan-1-one (13)
The 5-bromo derivative of 2-aminoacetophenone 13 has been
synthesised based on the reported procedure
46,47
.
Yellow solid, Yield 96%, m.p. 7779 C;
1
H NMR (400 MHz,
CDCl
3
)d(ppm): 2.55 (s, 3H, CH
3
), 6.29 (s, 2H, NH
2
), 6.54 (d, 1H,
phenyl CH, J¼8.8 Hz), 7.31 (dd, 1H, phenyl CH, J¼2.3, 8.8 Hz),
7.78 (d, 1H, phenyl CH, J¼2.3 Hz);
13
C NMR (100 MHz, CDCl
3
)d
(ppm): 27.83, 106.63, 118.99, 119.40, 134.11, 136.99, 149.08, 199.64;
HRESIMS (m/z): [M þH]
þ
Calcd for C
8
H
9
CBrNO, 213.98620;
found, 213.98599.
4.1.14. Synthesis of 6-bromo-2-arylquinolones (14a,b)
1-(2-amino-5-bromophenyl)ethan-1-one 13 was benzoylated with
p-chloro or fluorobenzoyl chloride using the same procedure for
3ac. Then, the resulted benzoyl derivatives have been subjected
to ring closure reaction according to the synthetic route for 4ac
to afford the corresponding 6-bromo-2-arylquinolones 14a,b.
4.1.14.1. 6-bromo-2-(4-chlorophenyl)quinolin-4(1H)-one (14a).
Yellow solid, Yield 95%, m.p. >250 C;
1
H NMR (400 MHz, CDCl
3
)d
(ppm): 6.41 (s, 1H, vinyl CH), 7.67 (d, 2H, chlorophenyl 2CH,
J¼8.5 Hz), 7.72 (d, 1H, bromophenyl CH, J¼8.9 Hz), 7.84 (dd, 1H,
bromophenyl CH, J¼1.7, 8.9 Hz), 7.87 (d, 2H, chlorophenyl 2CH,
J¼8.5 Hz), 8.17 (d, 1H, bromophenyl CH, J¼1.7 Hz), 11.91 (s, 1H,
NH);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 108.25, 116.52, 121.86,
126.76, 127.35, 129.53, 129.81, 133.14, 135.15, 135.96, 139.85,
149.64, 176.06; HRESIMS (m/z): [M þH]
þ
Calcd for C
15
H
10
BrClNO,
333.96288; found, 333.96295.
4.1.14.2. 6-bromo-2-(4-fluorophenyl)quinolin-4(1H)-one (14b).
Yellow solid, Yield 93%, m.p. >250 C;
1
H NMR (400 MHz, CDCl
3
)d
(ppm): 6.39 (s, 1H, vinyl CH), 7.44 (t, 2H, fluorophenyl 2CH,
J¼8.7 Hz), 7.72 (d, 1H, bromophenyl CH, J¼8.8 Hz), 7.84 (dd, 1H,
bromophenyl CH, J¼2.3, 8.8 Hz), 7.91 (dd, 2H, fluorophenyl 2CH,
J¼5.4, 8.7 Hz), 8.18 (d, 1H, bromophenyl CH, J¼2.3 Hz), 11.88 (s,
1H, NH);
13
C NMR (100 MHz, CDCl
3
)d(ppm): 108.14, 116.44,
116.50 (CH-C-F, d, J¼21.8 Hz), 121.83, 126.72, 127.35, 130.43 (CH-
CH-C-F, d, J¼8.7 Hz), 130.85, 135.07, 139.85, 149.88, 163.95 (C-F, d,
J¼248.3 Hz), 176.02;
19
F NMR (376.46 MHz, CDCl
3
)d(ppm):
110.21 (s); HRESIMS (m/z): [M þH]
þ
Calcd for C
15
H
10
BrFNO,
317.99243; found, 317.99265.
4.1.15. Synthesis of 6-bromo-2-arylquinolines key intermedi-
ates (15a,b)
The key intermediates 15a,b have been prepared from 14a,b
according to the synthetic route for 5ac.
366 M. M. ELBADAWI ET AL.