Synthesis and antiproliferative evaluation of 2,3-diarylquinoline derivatives

Article abstract of DOI:10.1039/c0ob01225d

A number of 2,3-diarylquinoline derivatives were synthesized and evaluated for antiproliferative activities against the growth of six cancer cell lines including human hepatocellular carcinoma (Hep G2 and Hep 3B), non-small cell lung cancer (A549 and H129

Full text of DOI:10.1039/c0ob01225d

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PAPER
Synthesis and antiproliferative evaluation of 2,3-diarylquinoline derivatives†
Chih-Hua Tseng,a,d Yeh-Long Chen,a,d Kuin-Yu Chung,a Chi-Huei Wang,b Shin-I Peng,a Chih-Mei Chengc and
Cherng-Chyi Tzeng*a,d
Received 21st December 2010, Accepted 14th February 2011
DOI: 10.1039/c0ob01225d
A number of 2,3-diarylquinoline derivatives were synthesized and evaluated for antiproliferative
activities against the growth of six cancer cell lines including human hepatocellular
carcinoma (Hep G2 and Hep 3B), non-small cell lung cancer (A549 and H1299), and breast
cancer (MCF-7 and MDA-MB-231) cell lines. The preliminary results indicated that
6-fluoro-2,3-bis{4-[2-(piperidin-1-yl)ethoxy]phenyl}quinoline (16b) was one of the most active
compounds against the growth of Hep 3B, H1299, and MDA-MB-231 with a GI50 value of 0.71, 1.46,
and 0.72 mM respectively which was more active than tamoxifen. Further investigations have shown
that 16b induced cell cycle arrest at G2/M phase followed by DNA fragmentation via an increase in the
protein expression of Bad, Bax and decrease in Bcl-2, and PARP which consequently cause cell death.
Introduction
The quinoline skeleton is one of the key building elements for a
large number of natural and synthetic heterocycles which possess a
wide variety of biological effects such as antimicrobial, antitumor,
and antiviral activities.1–11 Camptothecin is one of the examples
which bears a quinoline moiety and is an anticancer alkaloid
isolated from Camptotheca acuminate.1,2 We have also synthesized
certain iminoindeno[1,2-c]quinoline (1) and 6-arylindeno[1,2-
c]quinoline (2) derivatives which were found to be more potent
than camptothecin against the growth of human cancer cell
lines.12,13 In continuation of our study to explore more potent
anticancer drug candidates, we describe herein the preparation
of certain 2,3-diarylquinoline derivatives whose structures can be
related to 6-arylindeno[1,2-c]quinoline (2) in which the carbonyl
bridge at C-11 was eliminated (Fig. 1). The structures of these
2,3-diarylquinoline derivatives also resemble tamoxifen in which
the substituted ethylene bridge was replaced with quinoline,
and combretastatin A-414–17 in which the ethylene bridge was
replaced with quinoline. These 2,3-diarylquinoline derivatives
were evaluated in vitro against a panel of six cancer cell lines
including two human hepatocellular carcinoma (Hep G2 and
Fig.
1
Structures
of
indeno[1,2-c]quinolines
1,
6-aryl
indeno[1,2-c]quinolines 2, tamoxifen, combretastatin A-4 (CA-4),
and targeted compounds.
Hep 3B), two non-small cell lung cancer (A549 and H1299), and
two breast cancer (MCF-7 and MDA-MB-231) cell lines. These
cancers are common malignancies in the world, and are the leading
cause of cancer deaths in Asian countries including Taiwan.18–22
aDepartment of Medicinal and Applied Chemistry, College of Life
Science, Kaohsiung Medical University, Kaohsiung City, 807, Taiwan.
E-mail: tzengch@kmu.edu.tw; Fax: 886-7-312-5339; Tel: 886-7-312-
1101ext2123
Results and discussion
bDepartment of Biotechnology, Kaohsiung Medical University, Kaohsiung
City, 807, Taiwan
Chemistry
cDepartment of Biomedical Science and Environmental Biology, College of
Life Science, Kaohsiung Medical University, Kaohsiung City, 807, Taiwan
Pfitzinger reaction of 5-fluoroindolin-2,3-dione (3a) and de-
oxybenzoin (4a) under basic conditions gave 6-fluoro-2,3-
bisphenylquinoline-4-carboxylic acid (5) as described in Scheme 1.
Accordingly, 6-methoxy-2,3-bisphenylquinoline-4-carboxylic acid
(7) was obtained by the reaction of 5-methoxyindolin-2,3-dione
(3b) and deoxybenzoin (4a). Preparation of compounds 6 and 8
dCenter of Excellence for Environmental Medicine, Kaohsiung Medical
University, Kaohsiung City, 807, Taiwan
† Electronic supplementary information (ESI) available: Spectral data (1H
NMR and 13C NMR) for all new compounds is included. See DOI:
10.1039/c0ob01225d
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Scheme 1 Reagents and conditions: (i) KOH, EtOH, 80 ◦C, 48 h; (ii) PhOPh, 250 ◦C, 4 h.
were previously reported.13 2,3-Diarylquinoline derivatives 9–12
were synthesized in a fairly good yield by heating their respective
carboxylic acids 5–8 in diphenyl ether at 250 ◦C.
phenyl (dH = 7.17 ppm)/4-H (dH = 8.28 ppm) were observed (Fig.
2(C)). By comparison of 1H NMR spectra for 14a and 15a, down-
field shifts were observed for the alkylation of the C-3 phenyl
Demethylation of 6-fluoro-2,3-bis(4-methoxyphenyl)quinoline
(10) with HBr gave 6-fluoro-2,3-bis(4-hydroxyphenyl)quinoline
(13) which was then alkylated with N-(2-chloroethyl)pyrrolidine
moiety in which ortho-H (dH = 7.07 ppm) and meta-H (dH =
6.74 ppm) proton signals of 14a shifted down-field to ortho-H
(dH = 7.17 ppm) and meta-H (dH = 6.92 ppm) proton signals
respectively of 15a. Accordingly, down-field shifts were observed
for the alkylation of the C-2 phenyl moiety in which ortho-H
(dH = 7.21 ppm) and meta-H (dH = 6.68 ppm) proton signals
of 15a shifted down-field to ortho-H (dH = 7.34 ppm) and meta-
H (dH = 6.88 ppm) proton signals respectively of 14a. Similar
phenomena were observed for the comparison of 14a and 16a
in which ortho-H (dH = 7.07 ppm) and meta-H (dH = 6.74 ppm)
proton signals of 14a shifted down-field to ortho-H (dH = 7.17
ppm) and meta-H (dH = 6.92 ppm) proton signals respectively
of 16a. A mixture of 14b, 15b, and 16b was obtained from 13
by alkylation with N-(2-chloroethyl)piperidine while a mixture of
14c, 15c, and 16c was obtained from 13 by alkylation with 3-
chloro-N,N-dimethylpropanamine.
Treatment of 6-methoxy-2,3-diphenylquinoline (11) with HBr
gave 2,3-diphenylquinolin-6-ol (17) which was then alkylated
with N-(2-chloroethyl)pyrrolidine to afford 2,3-diphenyl-6-[2-
(pyrrolidin-1-yl)ethoxy]quinoline (19a) as described in Scheme
3. Accordingly, compounds 19b and 19c were obtained by the
alkylation of 17 with N-(2-chloroethyl)piperidine, and 3-chloro-
N,N-dimethylpropanamine respectively. Under the same reaction
conditions, 6-methoxy-2,3-bis(4-methoxyphenyl)quinoline (12)
to afford
a
mixture of 4-{6-fluoro-2-[4-(2-(pyrrolidin-1-
yl)ethoxy)phenyl]quinolin-3-yl}phenol (14a), 4-{6-fluoro-3-[4-(2-
(pyrrolidin-1-yl)ethoxyphenyl]-quinolin-2-yl}phenol (15a), and
6-fluoro-2,3-bis{4-[2-(pyrrolidin-1-yl)ethoxy]-phenyl}quinoline
(16a) in a yield of 27%, 33% and 39% respectively, as depicted in
Scheme 2.
The structural assignment of the alkylated products 14a, 15a,
and 16a was determined by 2D Nuclear Overhauser Effect (2D
NOESY) experiments, as shown in Fig. 2. Compound 14a was
assigned as a monoalkylated product at the C-2 phenyl moiety
by the correlation between OCH2 (dH = 4.11 ppm)/meta-H of
2-phenyl (dH = 6.88 ppm); ortho-H of 3-phenyl (dH = 7.07 ppm)/4-
H (dH = 8.27 ppm) (Fig. 2(A)). Compound 15a was assigned as a
monoalkylated product at the C-3 phenyl moiety by the correlation
between OCH2 (dH = 4.09 ppm)/meta-H of 3-phenyl (dH = 6.92
ppm); meta-H (dH = 6.92 ppm)/ortho-H (dH = 7.17 ppm); and
ortho-H of 3-phenyl (dH = 7.17 ppm)/4-H (dH = 8.27 ppm) (Fig.
2(B)). From the 2D NOESY spectrum of the dialkylated product
16a, similar correlations between OCH2 (dH = 4.08 ppm)/meta-
H of 3-phenyl (dH = 6.92 ppm), meta-H of 3-phenyl (dH = 6.92
ppm)/ortho-H of 3-phenyl (dH = 7.17 ppm), and ortho-H of 3-
Scheme 2 Reagents and conditions: (i) 48% HBr, HOAc, reflux, 48 h; (ii) NaH, alkyl halides, DMF, 80 ◦C, 25 min.
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Fig. 2 Comparative studies on the chemical shifts for 2D NOESY correlations and 1H NMR signals of the 2,3-diaryl aromatic part (d 6.60–7.40 ppm)
of 14a (A), 15a (B), and 16a (C).
was demethylated to give 2,3-dihydroxyphenylquinolin-6-ol (18)
which was then treated with N-(2-chloroethyl)pyrrolidine, N-(2-
chloroethyl)piperidine, and 3-chloro-N,N-dimethylpropanamine
cells, compared to control cells, by 50%. The GI50 results of 2,3-
diarylquinoline derivatives are summarized in Table 1. For the C-6
fluoro-substituted 2,3-diarylquinoline derivatives, introduction of
the methoxy or hydroxyl substituents in the para-position of the C-
2 and C-3 aryl moieties did not improve antiproliferative activity,
in that 6-fluoro-2,3-diphenylquinoline (9), its methoxy derivatives
10, and hydroxy derivatives 13 were inactive against all the cancer
cells tested with GI50 of >50 mM in each case. Further introduction
of an aminoalkyl side chain in the para-position of the C-2
aryl enhanced antiproliferative activity in that the five membered
(pyrrolidin-1-yl)ethyl derivative 14a, the six-membered (piperidin-
1-yl)ethyl derivative 14b, and the acyclic (dimethylamino)propyl
derivative 14c exhibited GI50 values of <10.59 mM in each case.
Introduction of an aminoalkyl side chain in the para-position of
the C-3 aryl resulted in selective antiproliferative activity against
the growth of Hep 3B cancer cells. Among them, 4-{6-fluoro-3-[4-
(2-(piperidin-1-yl)ethoxy)phenyl]quinolin-2-yl}phenol (15b) was
more active than its (dimethylamino)propyl counterpart 15c,
respectively
respectively.
to
afford
trialkylated
products
20a–c
Antiproliferation activity
All the synthesized 2,3-diarylquinoline derivatives were evalu-
ated in vitro against a panel of six cancer cell lines including
two human hepatocellular carcinoma cells (Hep G2 and Hep
3B), two non-small cell lung cancer cells (A549 and H1299)
and two breast cancer cells (MCF-7 and MDA-MB-231) us-
ing XTT (sodium 3¢-[1-(phenylamino-carbonyl)-3,4-tetrazolium]-
bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate) assay.23 The
concentration that inhibited the growth of 50% of cells (GI50) was
determined from the linear portion of the curve by calculating the
concentration of tested agent that reduced absorbance in treated
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Scheme 3 Reagents and conditions: (i) 48% HBr, HOAc, reflux, 48 h; (ii) NaH, alkyl halides, DMF, 80 ◦C, 40 min.
which in turn is more active than the (pyrrolidin-1-yl)ethoyl
counterpart 15a against the growth of Hep 3B, with GI50 values
of 0.74, 1.40, and 3.07 mM respectively. Further introduction of
the second piperidin-1-yl ethyl side chain enhanced antiprolif-
erative activity against certain specific cancer cells, in which 6-
fluoro-2,3-bis{4-[2-(piperidin-1-yl)ethoxy]phenyl}quinoline (16b)
was especially active against the growth of Hep 3B, H1299,
and MDA-MB-231 with GI50 values of 0.71, 1.46 and 0.72 mM
respectively. Compound 16b and its (dimethylamino)propyl coun-
terpart 16c exhibited comparable inhibitory activities towards Hep
3B, H1299, and MDA-MB-231, while the (pyrrolidin-1-yl)ethyl
counterpart 16a was much less active. Therefore, a side chain of six-
membered (piperidin-1-yl)ethyl or acyclic (dimethylamino)propyl
is more favorable than that of five-membered (pyrrolidin-1-
yl)ethyl for the 2,3-diphenylquinoline pharmacophore. Both com-
pounds 16b and 16c were found to be more active than the
positive tamoxifen against the growth of Hep 3B, H1299 and
MDA-MB-231.
Regarding the C-6 methoxy-substituted 2,3-diarylquinoline
derivatives, 6-methoxy-2,3-diphenylquinoline (11) was inactive.
Introduction of the methoxy substituents in the para-position of
both the C-2 and C-3 aryl moieties did not improve antiprolif-
erative activity, in that compound 12 was inactive against all the
cancer cell lines tested. However, their C-6 hydroxyl counterparts,
17 and 18, were weakly active against the growth of Hep 3B
with GI50 values of 9.48 and 12.03 mM respectively. For the
C-6 aminoalkoxy-substituted 2,3-diarylquinoline derivatives, a
side chain of six-membered (piperidin-1-yl)ethyl 19b or acyclic
(dimethylamino)propyl 19c is more favorable than that of five-
membered (pyrrolidin-1-yl)ethyl 19a against the growth of Hep
G2. Further introduction of aminoalkyl side chains in the
para-position of both the C-2 and C-3 aryl moieties enhanced
antiproliferative activity against the growth of Hep 3B, in that
the five membered (pyrrolidin-1-yl)ethyl derivative 20a, the six-
membered (piperidin-1-yl)ethyl derivative 20b, and the acyclic
(dimethylamino)propyl derivative 20c exhibited GI50 values of
2.18, 1.01, and 1.37 mM respectively.
inhibit the growth of Hep 3B with a GI50 value of less than
1.40 mM in each case. Among them, compound 16b exhibited
a GI50 value of 0.72 mM against the growth of MDA-MB-
231, which was 90-fold more active than the positive tamoxifen.
Therefore, compound 16b was selected for further evaluation of
its effect on the MDA-MB-231 cell cycle distribution by flow
cytometric analysis. Fig. 3 and Table 2 showed the cell cycle
arrest induced by 16b is in a concentration- and time-dependent
manner. The proportion of cells slightly decreased in the G1 and
accumulated in G2/M phase after 12 or 24 h treatment, while
the hypodiploid (sub-G0/G1 phase) cells increased. The images
obtained by immunofluorescence microscopy enabled indirect
evaluation of the effect of 16b on the microtubule network. The
microtubule network in control cells displayed intact organization
and arrangement. However, when cells were exposed to various
concentrations of 16b for 24 h, it exhibited filament-like structure
and reduced microtubule extent in the cytoplasm (Fig. 4). The
microtubule network shrank significantly at 1.0 mM and was
disrupted thoroughly at 10.0 mM. The morphological changes of
apoptosis include membrane blebbing, cell shrinkage, chromatin
condensation, and formation of apoptotic bodies.24 Fig. 5 also
demonstrates the incubation of the MDA-MB-231 cells with
different concentrations of 16b for 24 h results in significant
morphological changes. Cleavage of DNA at the internucleosomal
linker sites yielding DNA fragments in multiple fragments (180–
200 bp) was regarded as a biochemical hallmark of apoptosis.25
The appearance of such fragments resulted in a ladder formation
when fragmented DNA from 16b-treated cells was separated by
agarose gel electrophoresis (Fig. 6). The cells in sub-G0/G1 phase
indicate the cells are undergoing DNA fragmentation and cell
death. To explore the effect of compound 16b on apoptosis-related
proteins, Bcl-2 family proteins (Bcl-2, Bax, and Bad) and PARP
were evaluated in 16b-treated MDA-MB-231 cells by Western
blotting. Bcl-2 is the first identified member of a large family
of apoptosis-regulating proteins, consisting of blockers (such as
Bcl-2) and promoters (such as Bax and Bad) of cell death.26,27
PARP, a nuclear poly(ADP-ribose) polymerase, is involved in
DNA repair predominantly in response to environmental stress,
and is important for the maintenance of cell viability.28 Our
Among these C-6 substituted 2,3-diarylquinoline derivatives,
compounds 15b, 15c, 16b, 16c, 20b, and 20c were able to
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Table 1 Antiproliferative activity of 2,3-diarylquinoline derivatives [GI50, mM]a
Cell lines
MDA-MB-
231
Cpd
R1
R2
R3
Hep G2
Hep 3B
A549
H1299
MCF-7
9
F
F
OMe
OMe
F
H
OMe
H
OMe
OH
H
OMe
H
OMe
OH
OH
>50
>50
>50
>50
>50
6.62 0.05
>50
>50
>50
>50
>50
6.27 0.31
>50
>50
>50
>50
>50
6.59 0.12
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
7.36 0.02
10
11
12
13
14a
F
10.59 0.24 7.79 0.06
14b
F
OH
OH
6.39 0.06
6.43 0.10
10.28 3.87 10.06 0.73 10.27 2.45 6.33 0.06
14c
15a
15b
F
F
F
6.49 0.03
6.50 0.08
6.43 0.05
5.95 0.02
3.07 0.07
0.74 0.06
6.53 0.01
6.37 0.09
6.42 0.02
7.46 0.15
7.92 0.22
7.22 0.16
6.46 0.09
6.35 0.02
6.72 0.16
7.23 0.01
6.92 0.07
6.13 0.03
OH
OH
15c
16a
F
F
OH
6.43 0.01
6.50 0.06
1.40 0.05
6.45 0.08
6.56 0.05
6.58 0.05
6.71 0.09
6.58 0.04
6.47 0.05
6.50 0.07
6.18 0.03
6.21 0.01
16b
16c
F
F
6.27 0.02
6.20 0.10
0.71 0.03
6.72 0.81
1.46 0.01
1.53 0.10
6.26 0.01
6.61 0.08
0.72 0.09
0.97 0.06
0.63 0.03
9.48 2.16
12.03 0.95 >50
6.47 0.13
6.69 0.08
17
18
19a
OH
OH
H
OH
H
H
OH
H
>50
>50
>50
>50
>50
>50
9.06 0.08
>50
>50
8.31 0.59
10.42 0.74
>50
9.21 0.27
>50
19b
H
H
H
H
12.12 2.68 6.11 0.03
>50
10.17 0.91 10.06 1.58 7.64 0.27
19c
20a
7.25 0.12
6.79 0.58
6.21 0.07
2.18 0.10
8.74 2.16
6.55 0.07
8.46 2.47
6.47 0.07
8.35 0.51
6.36 0.01
7.65 0.28
6.67 0.05
20b
6.27 0.05
6.38 0.04
1.01 0.32
1.37 0.04
6.40 0.01
6.55 0.03
5.75 0.03
5.90 0.02
6.52 0.02
6.54 0.04
5.54 0.75
6.19 0.02
20c
Tamoxifen
51.40 3.51 7.12 0.03
57.98 0.41 74.58 1.48 15.27 3.21 64.42 3.52
a The concentration that inhibited the growth of 50% of cells (GI50) was determined from the linear portion of the curve by calculating the concentration
of tested agent that reduced absorbance in treated cells, compared to control cells, by 50%. Values are the average of three separate determinations.
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Fig. 3 Flow cytometric analysis of MDA-MB-231 cells. Cells were treated with DMSO (A), 1.0 mM (B), 5.0 mM (C) or 10.0 mM (D) for 12 h; DMSO (E),
1.0 mM (F), or 5.0 mM (G), or 10.0 mM (H) for 24 h of 16b; cells were harvested, fixed, and stained with propidium iodide as described in the Experimental
section. The percentage of cells in each cell cycle phase was quantified (Table 2).
Fig. 4 Microtubule effect of compound 16b. The confocal laser scanning micrograph shows a merged image double-labeled with DAPI and b-tubulin
antibodies. MDA-MB-231 cells were fixed after the treatment of 16b for 24 h followed by immunofluorescence analysis using anti-b-tubulin antibody,
FITC-conjugated secondary antibody, and DAPI staining as described in the Experimental section.
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Table 2 Effects of 16b on MDA-MB-231 cell cycle progression
Cell cycle distribution (%)
Time (h)
Concentration (mM)
Sub G1
G1
S
G2/M
12
12
12
12
24
24
24
24
DMSO
1.0
5.0
10.0
DMSO
1.0
1.9
2.3
3.2
8.1
2.7
6.2
15.3
20.9
72.6
69.8
58.2
46.2
70.4
59.9
45.9
38.4
18.1
18.4
13.5
16.1
17.6
18.6
17.1
14.1
7.4
9.5
25.1
29.6
9.3
15.3
21.7
26.6
5.0
10.0
Fig. 5 Induction of morphological change in MDA-MB-231 cells. Cells were treated with DMSO (A), compound 16b at 1 mM (B), 5 mM (C) or 10 mM
(D) for 24 h; at 37 ◦C and photographed under a microscope (100 ¥).
Fig. 7 Effects of 16b on the expression of Bcl-2, Bax, Bad, and PARP
in MDA-MB-231 cells. Exponentially growing MDA-MB-231 cells were
Fig. 6 Agarose gel electrophoresis for detecting DNA fragmentation in
treated with the indicated concentrations of 16b for 24 h. Cell lysates were
prepared and protein levels of Bcl-2, Bax, Bad, and PARP were determined
by Western blotting analysis. b-Actin was used to confirm equal protein
loading.
MDA-MB-231 cells treated with compound 16b for 24 h.
results indicated that 16b increased the protein expression of
Bad and Bax, but decreased expression of Bcl-2 and PARP
(Fig. 7). Thus, compound 16b induces cell cycle arrest at the
G2/M phase, followed by DNA fragmentation via an increase
in the protein expression of Bad and Bax but a decrease in
expression of Bcl-2 and PARP, which consequently cause cell
death.
Conclusions
A number of 2,3-diarylquinoline derivatives were synthesized and
evaluated for antiproliferative activities against the growth of Hep
G2, Hep 3B, A549, H1299, MCF-7, MDA-MB-231 cancer cell
lines. Among these C-6 substituted 2,3-diarylquinoline derivatives,
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compounds 15b, 15c, 16b, 16c, 20b, and 20c were able to inhibit
the growth of Hep 3B with a GI50 value of less than 1.40 mM in
each case. Therefore, a side chain of six-membered (piperidin-
1-yl)ethyl or acyclic (dimethylamino)propyl is more favorable
than that of five-membered (pyrrolidin-1-yl)ethyl for the 2,3-
diphenylquinoline pharmacophore. Compound 16b was one of
the most active against the growth of Hep 3B, H1299, and MDA-
MB-231 with a GI50 value of 0.71, 1.46, and 0.72 mM respectively.
Further investigations have shown that 16b induced cell cycle
arrest at the G2/M phase followed by DNA fragmentation via an
increase in the protein expression of Bad and Bax but a decrease
in expression of Bcl-2 and PARP, which consequently causes cell
death. Compound 16b was selected as a new lead for potential
anticancer drug candidates. Its structural optimization is ongoing.
13C NMR (100 MHz, DMSO-d6):55.57, 102.41, 122.76, 123.05,
127.51 (2C), 127.60, 127.65, 127.93 (2C), 129.66 (2C), 129.76,
130.08 (2C), 131.07, 137.19, 139.97, 140.26, 142.65, 155.63, 158.23,
168.19. Anal. calcd for C23H17NO3: C 77.73, H 4.82, N 3.94; found:
C 77.55, H 4.78, N 3.98.
6-Fluoro-2,3-diphenylquinoline (9). A mixture of 5 (3.43 g,
10 mmol) in diphenyl ether (15 mL) was heated at 250 ◦C for
4 h (TLC monitoring). The mixture was cooled and then 50 mL
hexane was added. The precipitate thus formed was collected,
washed with ether, and crystallized from EtOH to give 9 (2.04 g,
68%). M.p. 154–155 ◦C. Rf 0.52 (MeOH–CH2Cl2 1 : 200). UV
1
(MeOH): lmax nm (log e) 232 (4.67), 256 (4.54), 330 (3.85). H
NMR (400 MHz, DMSO-d6): 7.26–7.39 (m, 10H, Ar–H), 7.72
(ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.87 (dd, 1H, J = 9.2, 2.8 Hz,
5-H), 8.15 (dd, J = 9.2, 5.6 Hz, 8-H), 8.41 (s. 1H, 4-H). 13C NMR
(100 MHz, DMSO-d6): 110.86 (J = 22.0 Hz), 120.03 (J = 25.8 Hz),
127.45, 127.55 (J = 10.6 Hz), 127.77 (2C), 128.05, 128.32 (2C),
129.51 (2C), 129.74 (2C), 131.61 (J = 9.1 Hz), 134.69, 137.21 (J =
5.3 Hz), 139.25, 139.93, 143.82, 157.16 (J = 2.2 Hz), 159.94 (J =
244.1 Hz). Anal. calcd for C21H14FN·0.1 H2O: C 83.76, H 4.75, N
4.65; found: C 83.75, H 4.69, N 4.91.
Experimental section
General
Melting points were determined on an Electrothermal IA9100
melting point apparatus and are uncorrected. The ultraviolet-
visible (UV-VIS) absorption spectra were recorded on a Jasco
V570 spectrometer. Nuclear magnetic resonance (1H and 13C)
spectra were recorded on a Varian Gemini 200 spectrometer or
Varian-Unity-400 spectrometer. Chemical shifts were expressed in
parts per million (d) with tetramethylsilane (TMS) as an internal
standard. Thin-layer chromatography was performed on silica gel
60 F-254 plates purchased from E. Merck and Co.. The elemental
analyses were performed in the Instrument Center of National
Science Council at National Cheng-Kung University and National
Taiwan University using Heraeus CHN–O Rapid EA, and all
values are within 0.4% of the theoretical compositions.
6-Fluoro-2,3-bis(4-methoxyphenyl)quinoline (10). From 6 as
described for the preparation of 9: 67% yield. M.p. 189–190 ◦C
(EtOH). Rf 0.62 (MeOH–CH2Cl2 1 : 100). UV (MeOH): lmax nm
(log e) 222 (4.71), 231 (4.70), 272 (4.47), 342 (4.01), 340 (4.01). 1H
NMR (400 MHz, DMSO-d6): 3.74 and 3.75 (two s, 6H, OCH3 ¥
2), 6.84–6.91 (m, 4H, Ar–H), 7.16–7.18 (m, 2H, Ar–H), 7.31–7.33
(m, 2H, Ar–H), 7.64 (ddd, 1H, J = 9.2, 9.2, 3.2 Hz, 7-H), 7.78 (dd,
1H, J = 9.2, 2.8 Hz, 5-H), 8.08 (dd, 1H, J = 9.2, 5.6 Hz, 8-H),
8.27 (s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 55.11 (2C),
110.69 (J = 21.2 Hz), 113.24 (2C), 113.89 (2C), 119.63 (J = 25.7
Hz), 127.42 (J = 10.6 Hz), 130.62 (2C), 131.14 (2C), 131.42 (J =
9.1 Hz), 131.67, 132.38, 134.24, 136.87 (J = 4.5 Hz), 143.70, 156.81
(J = 2.2 Hz), 158.62, 159.14, 159.75 (J = 243.3 Hz). Anal. calcd
for C23H18FNO2: C 76.86, H 5.05, N 3.90; found: C 76.57, H 5.05,
N 4.20.
6-Fluoro-2,3-diphenylquinoline-4-carboxylic acid (5). A mix-
ture of 5-fluoroisatin (3a, 3.30 g, 20 mmol), deoxybenzoin (4a,
4.71 g, 24 m◦mol), and KOH (3.37 g, 60 mmol) in EtOH was
heated at 80 C for 48 h (TLC monitoring). Evaporation of the
solvent afforded a residue which was dissolved in H2O (50 mL),
and the solution was washed twice with Et2O (30 mL). The ice-
cold aqueous phase was acidified to pH 1 with 37% HCl, and
the precipitate was collected, washed with H2O, and crystallized
from EtOH to give 5 (5.49 g, 80%). M.p. 317–318 ◦C. Rf 0.51
(MeOH–CH2Cl2 1 : 5). UV (MeOH): lmax nm (log e) 231 (4.67),
328 (3.71). 1H NMR (400 MHz, DMSO-d6): 7.21–7.33 (m, 10H,
Ar–H), 7.54 (dd, 1H, J = 9.6, 3.2 Hz, 5-H), 7.82 (ddd, 1H, J =
9.6, 8.8, 3.2 Hz, 7-H), 8.25 (dd, 1H, J = 9.2, 5.2 Hz, 8-H). 13C
NMR (100 MHz, DMSO-d6): 108.12 (J = 22.7 Hz), 120.63 (J =
25.0 Hz), 122.78 (J = 10.6 Hz), 127.60 (2C), 127.83, 128.02 (2C),
129.70 (2C), 130.03 (2C), 130.45, 132.54 (J = 9.8 Hz), 136.79,
139.67 (2C), 140.99 (J = 5.3 Hz), 143.74, 157.97, 160.53 (J = 245.6
Hz), 167.74. Anal. calcd for C22H14FNO2: C 76.96, H 4.11, N 4.08;
found: C 76.64, H 4.10, N, 4.37.
6-Methoxy-2,3-diphenylquinoline (11). From 7 as described for
the preparation of 9: 55% yield. M.p. 170-172 ◦C (EtOH). Rf 0.43
(MeOH–CH2Cl2 1 : 100). UV (MeOH): lmax nm (log e) 260 (4.67),
230 (4.65), 221 (4.63), 340 (3.90), 336 (3.90), 343 (3.90). 1H NMR
(400 MHz, DMSO-d6):3.91 (s, 3H, OCH3), 7.22–7.35 (m, 10H, Ar–
H), 7.41–7.45 (m, 2H, 7- and 8-H), 7.97 (d, 1H, J = 8.4 Hz, 5-H),
8.25 (s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 55.72, 105.64,
122.62, 127.38, 127.84 (2C), 127.92, 128.10, 128.42 (2C), 129.64
(2C), 129.86 (2C), 130.32, 134.27, 136.62, 139.83, 140.38, 142.82,
155.15, 157.73. Anal. calcd for C22H17NO·0.2 H2O: C 83.89, H
5.57, N 4.45; found: C 83.90, H 5.51, N 4.73.
6-Methoxy-2,3-bis(4-methoxyphenyl)quinoline (12). From 8 as
described for the preparation of 9: 62% yield. M.p. 115–116 ◦C
(EtOH). Rf 0.41 (MeOH–CH2Cl2 1 : 100). UV (MeOH): lmax nm
1
6-Methoxy-2,3-diphenylquinoline-4-carboxylic acid (7). From
5-methoxyisatin (3b) and deoxybenzoin (4a) as described for the
preparation of 5 in 85% yield. M.p. 321–322 ◦C (EtOH). Rf 0.54
(MeOH–CH2Cl2 1 : 5). UV (MeOH): lmax nm (log e) 230 (4.63),
218 (4.61). 1H NMR (400 MHz, DMSO-d6): 3.91 (s, 3H, OCH3),
7.10 (d, 1H, J = 2.8 Hz, 5-H), 7.19–7.32 (m, 10H, Ar–H), 7.53
(dd, 1H, J = 9.2, 2.8 Hz, 7-H), 8.08 (d, 1H, J = 9.6 Hz, 8-H).
(log e) 226 (4.70), 246 (4.67), 271 (4.56), 349 (4.07). H NMR
(400 MHz, DMSO-d6): 3.75, 3.77 and 3.91 (three s, 9H, OCH3 ¥
3), 6.83–9.87 (m, 2H, Ar–H), 6.90–6.93 (m, 2H, Ar–H), 7.17–
7.20 (m, 2H, Ar–H), 7.30–7.33 (m, 2H, Ar–H), 7.38–7.41 (m,
2H, 5- and 8-H), 7.96 (dd, 1H, J = 9.6, 0.8 Hz, 7-H), 8.17 (s,
1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 55.06, 55.07, 55.52,
105.40, 113.14 (2C), 113.82 (2C), 122.05, 127.81, 130.06, 130.58
3212 | Org. Biomol. Chem., 2011, 9, 3205–3216
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(2C), 131.04 (2C), 132.15, 132.75, 133.65, 136.17, 142.58, 154.67,
157.34, 158.45, 158.85. Anal. calcd for C24H21NO3: C 77.61, H
5.70, N 3.77; found: C 77.37, H 5.75, N 4.08.
13C NMR (100 MHz, DMSO-d6): 23.10 (2C), 54.02 (2C), 54.23,
66.45, 110.66 (J = 21.2 Hz), 114.36 (2C), 114.63 (2C), 119.53 (J =
25.8 Hz), 127.33 (J = 10.6 Hz), 130.60 (2C), 130.77, 131.18 (2C),
131.33 (J = 9.0 Hz), 131.86, 134.22, 136.75 (J = 5.3 Hz), 143.70,
157.16 (J = 2.2 Hz), 157.44, 157.77, 159.66 (J = 242.5 Hz). Anal.
calcd for C27H25FN2O2·0.5H2O: C 74.12, H 5.99, N 6.40; found: C
74.10, H 5.99, N, 6.52.
Compound 16a (0.21 g, 39%) was obtained as a white oil. Rf
0.52 (MeOH–CH2Cl2 1 : 3). UV (MeOH): lmax nm (log e) 219
(4.80), 221 (4.80), 271 (4.52), 340 (4.00), 342 (4.00). 1H NMR (400
MHz, DMSO-d6): 1.67–1.73 (m, 8H, pyrrolidinyl-H), 2.58 (br s,
8H, pyrrolidinyl-H), 2.82–2.86 (m, 4H, CH2N), 4.06–4.10 (m, 4H,
OCH2), 6.86–6.94 (m, 4H, Ar–H), 7.15–7.19 (m, 2H, Ar–H), 7.31–
7.34 (m, 2H, Ar–H), 7.64 (ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.79
(dd, 1H, J = 9.6, 2.8 Hz, 5-H), 8.09 (dd, 1H, J = 8.8, 5.2 Hz, 8-H),
8.28 (s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 23.09 (4C),
53.97 (4C), 54.13, 54.14, 66.37 (2C), 110.67 (J = 21.9 Hz), 113.72
(2C), 114.39 (2C), 119.58 (J = 25.8 Hz), 127.42 (J = 10.6 Hz),
130.61 (2C), 131.15 (2C), 131.39 (J = 25.0 Hz), 131.69, 132.40,
134.19, 136.84 (J = 4.5 Hz), 143.71, 156.75, 157.80, 158.31, 159.74
(J = 243.2 Hz). Anal. calcd for C33H36FN3O2·0.5H2O: C 74.13, H
6.98, N 7.86; found: C 73.98, H 7.24, N 7.65.
6-Fluoro-2,3-bis(4-hydroxyphenyl)quinoline (13). A solution of
10 (0.36 g, 1.0 mmol) in 48% HBr (5 mL) was heated at reflux for
48 h. The mixture was cooled and evaporated in vacuo to give a
residue which was treated with H2O (50 mL). The crude product
was collected and crystallized from MeOH to give 13 (0.31 g,
94%). M.p. 269–270 ◦C (MeOH). Rf 0.52 (MeOH–CH2Cl2 1 : 35).
UV (MeOH): lmax nm (log e) 221 (4.70), 273 (4.43), 345 (4.01). 1H
NMR (400 MHz, DMSO-d6): 6.66–6.75 (m, 4H, Ar–H), 7.04–7.08
(m, 2H, Ar–H), 7.21–7.24 (m, 2H, Ar–H), 7.63 (ddd, 1H, J = 8.2,
8.8, 2.8 Hz, 7-H), 7.78 (dd, 1H, J = 9.2, 2.4 Hz, 5-H), 8.07 (dd,
1H, J = 9.2, 5.6 Hz, 8-H), 8.24 (s, 1H, 4-H), 9.57 and 9.61 (two s,
2H, OH). 13C NMR (100 MHz, DMSO-d6): 110.60 (J = 22.0 Hz),
114.57 (2C), 115.24 (2C), 119.35 (J = 25.7 Hz), 127.37 (J = 10.6
Hz), 130.16, 130.57 (2C), 130.88, 131.16 (2C), 131.30 (J = 9.1 Hz),
134.62, 136.48 (J = 5.3 Hz), 143.60, 156.78, 157.22 (J = 2.3 Hz),
157.39, 159.64 (J = 242.5 Hz). Anal. calcd for C21H14FNO2·1.0
H2O: C 72.20, H 4.62, N 4.01; found: C 72.10, H 4.90, N 4.25.
4-{6-Fluoro-2-[4-(2-(pyrrolidin-1-yl)ethoxy)phenyl]quino-lin-3-yl}-
phenol (14a), 4-{6-Fluoro-3-[4-(2-(pyrrolidin-1-yl)ethoxy)phenyl]-
quinolin-2-yl}phenol (15a) and 6-Fluoro-2,3-bis{4-[2-(pyrrolidin-
1-yl)ethoxy]-phenyl}quinoline (16a). To a stirred solution of 13
(0.33 g, 1.0 mmol)◦in dry DMF (20 mL) was added NaH (60%
in oil, 0.50 g) at 0 C for 1 h. N-(2-Chloroethyl)pyrrolidine·HCl
(0.51 g, 3 mmol) was added and heated at 80 ◦C for 25 min.
The reaction mixture was partitioned between H2O (50 mL)
and CH2Cl2 (50 mL). The organic layer was dried over
MgSO4 and evaporated. The resulting residue was purified by
column chromatography (MeOH–CH2Cl2 1/10) to give three
fractions which were evaporated to dryness and the residue was
recrystallized from EtOH.
4-{6-Fluoro-2-[4-(2-(piperidin-1-yl)ethoxy)phenyl]-quino-lin-3-yl}-
phenol (14b), 4-{6-Fluoro-3-[4-(2-(piperidin-1-yl)ethoxy)phenyl]-
quinolin-2-yl}phenol (15b) and 6-Fluoro-2,3-bis{4-[2-(piperidin-
1-yl)ethoxy]phenyl}quinoline (16b). From 13 and N-(2-
chloroethyl)piperidine·HCl as described for the preparation of
14b, 15b, and 16b.
Compound 14b (0.11 g, 25%) was obtained as a white solid. M.p.
113–115 ◦C (EtOH). Rf 0.50 (MeOH–CH2Cl2 1 : 10). UV (MeOH):
1
lmax nm (log e) 222 (4.78), 272 (4.50), 340 (4.02), 343 (4.01). H
NMR (400 MHz, DMSO-d6): 1.36–1.40 (m, 2H, piperidinyl-H),
1.47–1.53 (m, 4H, piperidinyl-H), 2.45 (br s, 4H, piperidinyl-H),
2.67 (t, 2H, J = 5.6 Hz, CH2N), 4.06 (t, 2H, J = 5.6 Hz, OCH2),
6.71–6.75 (m, 2H, Ar–H), 6.85–6.87 (m, 2H, Ar–H), 7.05–7.07
(m, 2H, Ar–H), 7.31–7.33 (m, 2H, Ar–H), 7.64 (ddd, 1H, J = 8.8,
8.8, 2.8 Hz, 7-H), 7.79 (dd, 1H, J = 9.6, 2.8 Hz, 5-H), 8.08 (dd,
1H, J = 9.6, 5.6 Hz, 8-H), 8.26 (s, 1H, 4-H), 9.59 (br s, 1H, OH).
13C NMR (100 MHz, DMSO-d6): 23.79, 25.40 (2C), 54.34 (2C),
57.25, 65.42, 110.61 (J = 22.0 Hz), 113.73 (2C), 115.29 (2C), 119.44
(J = 25.7 Hz), 127.45 (J = 10.6 Hz), 129.99, 130.58 (2C), 131.10
(2C), 131.37 (J = 9.1 Hz), 132.49, 134.61, 136.62 (J = 5.0 Hz),
143.60, 156.84 (2C), 158.34, 159.72 (J = 243.3 Hz). Anal. calcd for
C28H27FN2O2·0.8 H2O: C 73.60, H 6.31, N 6.13; found: C 73.58,
H 6.61, N, 6.00.
Compound 14a (0.12 g, 27% yield) was obtained as a white
◦
solid. M.p. 113–114 C (EtOH). Rf 0.44 (MeOH–CH2Cl2 1 : 10).
UV (MeOH): lmax nm (log e) 220 (4.76), 272 (4.47), 340 (4.01), 343
(3.98). 1H NMR (400 MHz, DMSO-d6): 1.74 (m, 4H, pyrrolidinyl-
H), 2.68 (m, 4H, pyrrolidinyl-H), 2.94 (m, 2H, CH2N), 4.11 (t, 2H,
J = 5.6 Hz, OCH2), 6.72–6.76 (m, 2H, Ar–H), 6.87–6.90 (m, 2H,
Ar–H), 7.05–7.09 (m, 2H, Ar–H), 7.33–7.35 (m, 2H, Ar–H), 7.65
(ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.80 (dd, 1H, J = 9.6, 2.8 Hz,
5-H), 8.08 (dd, 1H, J = 9.2, 5.6 Hz, 8-H), 8.27 (s, 1H, 4-H), 9.60 (br
s, 1H, OH). 13C NMR (100 MHz, DMSO-d6): 23.02 (2C), 54.00
(2C), 54.08, 66.01, 110.64 (J = 21.9 Hz), 113.72 (2C), 115.30 (2C),
119.48 (J = 25.7 Hz), 127.48 (J = 10.6 Hz), 129.99, 130.60 (2C),
131.14 (2C), 131.38 (J = 9.9 Hz), 132.62, 134.62, 136.60 (J = 4.2
Hz), 143.60, 156.84, 158.18, 159.73 (J = 243.3 Hz). Anal. calcd for
C27H25FN2O2·1.7 H2O: C 70.63, H, 6.23, N 6.10; found: C 70.38,
H 5.93, N 6.08.
Compound 15b (0.13 g, 30%) was obtained as a white solid. M.p.
124–125 ◦C (EtOH). Rf 0.62 (MeOH–CH2Cl2 1 : 10). UV (MeOH):
1
lmax nm (log e) 221 (4.79), 272 (4.48), 340 (4.02), 342 (4.02). H
NMR (400 MHz, DMSO-d6): 1.36–1.41 (m, 2H, piperidinyl-H),
1.48–1.53 (m, 4H, piperidinyl-H), 2.45 (br s, 4H, piperidinyl-H),
2.67 (t, 2H, J = 5.6 Hz, CH2N), 4.07 (t, 2H, J = 5.6 Hz, OCH2),
6.66–6.70 (m, 2H, Ar–H), 6.90–6.94 (m, 2H, Ar–H), 7.15–7.24 (m,
4H, Ar–H), 7.65 (ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.79 (dd, 1H,
J = 9.2, 2.8 Hz, 5-H), 8.08 (dd, 1H, J = 9.2, 5.6 Hz, 8-H), 8.27 (s,
1H, 4-H), 9.63 (br s, 1H, OH). 13C NMR (100 MHz, DMSO-d6):
23.83, 25.46 (2C), 54.37 (2C), 57.30, 65.49, 110.63 (J = 22.0 Hz),
114.38 (2C), 114.61 (2C), 119.48 (J = 25.8 Hz), 127.30 (J = 10.6
Hz), 130.55 (2C), 130.76, 131.14 (2C), 131.30 (J = 9.1 Hz), 131.80,
Compound 15a (0.15 g, 33%) was obtained as a white solid.
M.p. 122–123 ◦C (EtOH). Rf 0.52 (MeOH–CH2Cl2 1 : 10). UV
1
(MeOH): lmax nm (log e) 221 (4.77), 272 (4.46), 343 (4.02). H
NMR (400 MHz, DMSO-d6): 1.70–1.72 (m, 4H, pyrrolidinyl-H),
2.58 (br s, 4H, pyrrolidinyl-H), 2.85 (t, 2H, J = 5.6 Hz, CH2N),
4.09 (t, 2H, J = 5.6 Hz, OCH2), 6.66–6.70 (m,2H, Ar–H), 6.92-6.95
(m, 2H, Ar–H), 7.16-7.23 (m, 4H, Ar–H), 7.65 (ddd, 1H, J = 9.2,
9.2, 3.2 Hz, 7-H), 7.79 (dd, 1H, J = 9.2, 2.8 Hz, 5-H), 8.08 (dd,
1H, J = 9.2, 5.2 Hz, 8-H), 8.27 (s, 1H, 4-H), 9.64 (br s, 1H, OH).
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1
134.21, 136.71 (J = 5.3 Hz), 143.68, 157.15, 157.41, 157.81, 159.64
(J = 243.3 Hz). Anal. calcd for C28H27FN2O2·1.0H2O: C, 73.01; H,
6.36; N, 6.08; found: C, 73.07; H, 6.29; N, 6.15.
e) 220 (4.79), 272 (4.46), 340 (3.97), 342 (3.97). H-NMR (400
MHz, DMSO-d6): 2.08–2.16 (m, 4H, OCH2CH2CH2 ¥ 2), 2.66
and 2.67 (two s, 12H, NMe2 ¥ 2), 3.04–3.09 (m, 4H, CH2N), 4.05–
4.09 (m, 4H, OCH2), 6.87–6.96 (m, 4H, Ar–H), 7.18–7.22 (m, 2H,
Ar–H), 7.32–7.36 (m, 2H, Ar–H), 7.67 (ddd, 1H, J = 9.2, 9.2, 3.2
Hz, 7-H), 7.82 (dd, 1H, J = 9.6, 2.8 Hz, 5-H), 8.10 (dd, 1H, J =
9.2, 5.6 Hz, 8-H), 8.31 (s, 1H, 4-H). 13C NMR (100 MHz, DMSO-
d6): 24.31 (2C), 42.48 (4C), 54.17 (2C), 65.04, 65.07, 110.71 (J =
21.3 Hz), 113.75 (2C), 114.41 (2C), 119.66 (J = 25.8 Hz), 127.42
(J = 10.6 Hz), 130.64 (2C), 131.15 (2C), 131.25 (J = 20.5 Hz),
131.85, 132.55, 134.17, 136.88 (J = 5.3 Hz), 143.69, 156.72 (J =
2.2 Hz), 157.70, 158.20, 159.74 (J = 243.2 Hz). Anal. calcd for
C31H36FN3O2·0.3 H2O: C 73.43, H 7.28, N 8.29; found: C 73.44,
H 7.40, N 8.08.
Compound 16b (0.21 g, 38%) was obtained as a white oil. Rf 0.53
(MeOH–CH2Cl2 1 : 4). UV (MeOH): lmax nm (log e) 220 (4.82),
271 (4.50), 340 (3.99). 1H NMR (400 MHz, DMSO-d6): 1.36–1.40
(m, 4H, piperidinyl-H), 1.46–1.52 (m, 8H, piperidinyl-H), 2.45 (br
s, 8H, piperidinyl-H), 2.67 (br s, 4H, CH2N), 4.05–4.09 (m, 4H,
OCH2), 6.85–6.94 (m, 4H, Ar–H), 7.16–7.19 (m, 2H, Ar–H), 7.31–
7.34 (m, 2H, Ar–H), 7.66 (ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.80
(dd, 1H, J = 9.2, 2.8 Hz, 5-H), 8.09 (dd, 1H, J = 9.2, 5.6 Hz, 8-H),
8.29 (s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 23.79 (2C),
25.42 (4C), 54.34 (4C), 57.26 (2C), 65.46 (2C), 110.64 (J = 21.2
Hz), 113.76 (2C), 114.43 (2C), 119.57 (J = 25.8 Hz), 127.39 (J =
10.6 Hz), 130.57 (2C), 131.09 (2C), 131.38 (J = 9.9 Hz), 131.64,
132.34, 134.20, 136.80 (J = 5.4 Hz), 143.68, 156.77, 157.84, 158.35,
1159.72 (J = 243.3 Hz). Anal. calcd for C35H40FN3O2·0.4 H2O: C
74.94, H 7.33, N 7.49; found: C 75.06, H 7.42, N 7.54.
2,3-Diphenylquinolin-6-ol (17). From 11 as described for the
preparation of 13: 94% yield. M.p. 212–213 C (EtOH). Rf 0.53
◦
(MeOH–CH2Cl2 1 : 20). UV (MeOH): lmax nm (log e) 260 (4.61),
228 (4.61), 346 (3.85), 343 (3.85), 340 (3.85). 1H-NMR (400 MHz,
DMSO-d6): 7.23–7.37 (m, 12H, Ar–H), 7.95 (d, 1H, J = 8.8
Hz, 8-H), 8.17 (s, 1H, 4-H), 10.11 (s, 1H, OH). 13C-NMR (100
MHz, DMSO-d6): 108.12, 122.46, 127.08, 127.53, 127.62 (2C),
128.18 (2C), 128.23, 129.51 (2C), 129.69 (2C), 130.24, 133.89,
135.83, 139.86, 140.43, 141.95, 154.20, 155.87. Anal. calcd for
C21H15NO·0.2 H2O: C 83.81, H 5.16, N 4.65; found: C 83.74, H
5.16, N, 4.91.
4-{2-[4-(3-(Dimethylamino)propoxy)phenyl]-6-fluoro-quinolin-3-
yl}phenol (14c), 4-{3-[4-(3-(Dimethylamino)-propoxy)phenyl]-
6-fluoroquinolin-2-yl}phenol (15c) and 3,3¢-[4,4¢-(6-Fluoro-
quinoline-2,3-diyl)bis(4,1-phenylene)]bis(oxy)-bis(N,N -dimethyl-
propan-1-amine)
(16c). From
13
and
3-chloro-N,N-
dimethylpropanamine·HCl as described for the preparation
of 14c, 15c, and 16c.
Compound 14c (0.11 g, 26%) was obtained as a white solid. M.p.
128–130 ◦C (EtOH). Rf 0.42 (MeOH–CH2Cl2 1 : 4). UV (MeOH):
lmax nm (log e) 220 (4.74), 272 (4.44), 345 (3.96), 340 (3.96). H
2,3-Dihydroxyphenylquinolin-6-ol (18). From 12 as described
for the preparation of 13: 97% yield. M.p. 309-310 ◦C (EtOH).
Rf 0.50 (MeOH–CH2Cl2 1 : 10). UV (MeOH): lmax nm (log e) 219
1
NMR (400 MHz, DMSO-d6): 1.87–1.94 (m, 2H, OCH2CH2CH2),
2.27 (s, 6H, NMe2), 2.51–2.54 (m, 2H, CH2N), 4.01 (t, 2H, J = 6.4
Hz, OCH2), 6.74–6.77 (m, 2H, Ar–H), 6.84–6.88 (m, 2H, Ar–H),
7.05–7.08 (m, 2H, Ar–H), 7.31–7.35 (m, 2H, Ar–H), 7.64 (ddd,
1H, J = 8.8, 8.8, 2.8 Hz, 7-H), 7.80 (dd, 1H, J = 9.2, 2.8 Hz, 5-H),
8.08 (dd, 1H, J = 9.2, 5.6 Hz, 8-H), 8.27 (s, 1H, 4-H), 9.66 (br s, 1H,
OH). 13C NMR (100 MHz, DMSO-d6): 26.25, 44.54 (2C), 55.30,
65.55, 110.62 (J = 21.2 Hz), 113.63 (2C), 115.30 (2C), 119.44 (J =
25.0 Hz), 127.45 (J = 10.6 Hz), 129.93, 130.55 (2C), 131.11 (2C),
131.36 (J = 9.9 Hz), 132.43, 134.62, 136.59 (J = 5.3 Hz), 143.59,
156.84 (J = 2.3 Hz), 156.89, 158.42, 159.70 (J = 243.2 Hz). Anal.
calcd for C26H25FN2O2·1.6 H2O: C 70.13, H 6.38, N 6.29; found:
C 69.99, H 6.13, N 6.19.
1
(4.62), 245 (4.51), 265 (4.46), 355 (3.91). H NMR (400 MHz,
DMSO-d6): 6.64–6.72 (m, 4H, Ar–H), 7.03–7.05 (m, 2H, Ar–H),
7.16–7.19 (m, 3H, 5-H and Ar–H), 7.28 (dd, 1H, J = 9.2 and 2.8
Hz, 7-H), 7.85 (d, 1H, J = 9.2 Hz, 8-H), 8.01 (s, 1H, 4-H), 9.51
and 9.99 (two br s, 3H, OH). 13C NMR (100 MHz, DMSO-d6):
108.00, 114.45 (2C), 115.11 (2C), 121.85, 128.07, 130.01, 130.56
(2C), 130.77, 131.01 (2C), 131.45, 133.82, 135.21, 141.74, 154.39,
154.42, 156.49, 156.93. Anal. calcd for C21H15NO3·0.2 H2O: C
75.75, H 4.66, N 4.21; found: C 75.81, H 4.54, N 4.19.
2,3-Diphenyl-6-[2-(pyrrolidin-1-yl)ethoxy]quinoline (19a). To a
stirred solution of 17 (0.30 g, 1 mmol) in dry DMF (20 mL)
was added NaH (60% in oil, 0.50 g) at 0 ◦C for 1 h. N-(2-
Chloroethyl)pyrrolidine·HCl (0.68 g, 4 mmol) was added and
the mixture was heated at 80 ◦C for 1 h. The reaction mixture
was partitioned between H2O (50 mL) and CH2Cl2 (50 mL).
The organic layer was dried over MgSO4 and concentrated.
The resulting residue was purified by column chromatography
(MeOH–CH2Cl2 1/10) and recrystallized from EtOH to give 19a
(0.32 g, 82%) as a white solid. M.p. 116–117 ◦C (EtOH). Rf 0.40
(MeOH–CH2Cl2 1 : 20). UV (MeOH): lmax nm (log e) 229 (4.66),
216 (4.65), 259 (4.56), 340 (3.84). 1H NMR (400 MHz, DMSO-d6):
1.68–1.72 (m, 4H, pyrrolidinyl-H), 2.54–2.58 (m, 4H, pyrrolidinyl-
H), 2.88 (t, 2H, J = 6.0 Hz, CH2N), 4.23 (t, 2H, J = 6.0 Hz, OCH2),
7.24–7.37 (m, 10H, Ar–H), 7.44 (dd, 1H, J = 9.2, 2.8 Hz, 7-H),
7.47 (d, 1H, J = 2.8 Hz, 5-H), 7.98 (d, 1H, J = 9.2 Hz, 5-H), 8.25
(s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 23.16 (2C), 54.03
(2C), 54.20, 67.16, 106.24, 122.65, 127.22, 127.68 (2C), 127.96,
128.28 (2C), 129.49 (2C), 129.74 (2C), 130.29, 134.10, 136.35,
136.55, 139.75, 140.28, 142.66, 154.96, 156.77. Anal. calcd for
Compound 15c (0.13 g, 32%) was obtained as yellow solid. M.p.
132–134 ◦C (EtOH). Rf 0.52 (MeOH–CH2Cl2 1 : 8). UV (MeOH):
1
lmax nm (log e) 220 (4.74), 271 (4.42), 343 (3.96), 340 (3.96). H
NMR (400 MHz, DMSO-d6): 2.05–2.12 (m, 2H, OCH2CH2CH2),
2.73 (s, 6H, NMe2), 3.10–3.14 (m, 2H, CH2N), 4.06 (t, 2H, J = 6.0
Hz, OCH2), 6.66–6.70 (m, 2H, Ar–H), 6.91–6.95 (m, 2H, Ar–H),
7.18–7.24 (m, 4H, Ar–H), 7.65 (ddd, 1H, J = 8.8, 8.8, 2.8 Hz, 7-H),
7.81 (dd, 1H, J = 9.6, 2.8 Hz, 5-H), 8.08 (dd, 1H, J = 9.2, 5.2 Hz,
8-H), 8.27 (s, 1H, 4-H), 9.63 (s, 1H, OH). 13C NMR (100 MHz,
DMSO-d6): 24.33, 42.69 (2C), 54.43, 64.89, 110.63 (J = 22.0 Hz),
114.33 (2C), 114.60 (2C), 119.53 (J = 25.8 Hz), 127.28 (J = 10.6
Hz), 130.58 (2C), 130.76, 131.12 (2C), 131.31 (J = 9.1 Hz), 132.08,
134.13, 136.69 (J = 5.3 Hz), 143.68, 157.15, 157.40, 157.59, 159.64
(J = 243.3 Hz). Anal. calcd for C26H25FN2O2·0.5 H2O: C 73.39, H
6.16, N 6.58; found: C 73.22, H 6.04, N 6.68.
Compound 16c (0.20 g, 39%) was obtained as white oil. Rf 0.63
(MeOH–CH2Cl2/NH4OH 1 : 5 : 0.01). UV (MeOH): lmax nm (log
3214 | Org. Biomol. Chem., 2011, 9, 3205–3216
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1
C27H26N2O·0.5 H2O: C 80.36, H 6.74, N 6.94; found: C 80.16; H
(4.56), 345 (3.91), 347 (3.91). H NMR (400 MHz, DMSO-d6):
1.35–1.39 (m, 6H, piperidinyl-H), 1.44–1.54 (m, 12H, piperidinyl-
H), 2.36–2.46 (m, 12H, piperidinyl-H), 2.61–2.65 (m, 4H, CH2N),
2.73 (t, 2H, J = 6.0 Hz, CH2N), 4.02–4.06 (m, 4H, OCH2), 4.20
(t, 2H, J = 6.0 Hz, OCH2), 6.82–6.91 (m, 4H, Ar–H), 7.13–7.16
(d, 2H, Ar–H), 7.38–7.30 (d, 2H, Ar–H), 7.6–7.41 (m, 2H, 5- and
7-H), 7.91 (d, 1H, J = 9.2 Hz, 8-H), 8.12 (s, 1H, 4-H). 13C NMR
(100 MHz, DMSO-d6): 23.90 (3C), 25.54 (6C), 54.42 (6C), 57.22,
57.35, 57.37, 65.52 (2C), 65.97, 106.20, 113.65 (2C), 114.36 (2C),
122.22, 127.80, 130.02, 130.52 (2C), 131.01 (2C), 132.12, 132.70,
133.59, 136.10, 142.52, 154.61, 156.50, 157.70, 158.10. Anal. calcd
for C42H54N4O3·0.5 H2O: C 75.08, H 8.25; N 8.34; found: C 75.18,
H 8.07, N 8.37.
6.82, N 6.96.
2,3-Diphenyl-6-[2-(piperidin-1-yl)ethoxy]quinoline
(19b).
From 17 and N-(2-chloroethyl)piperidine·HCl as described for
the preparation of 19a. Compound 19b was obtained in 85%
yield (0.35 g) as a white oil. Rf 0.54 (MeOH–CH2Cl2 1 : 20). UV
(MeOH): lmax nm (log e) 230 (4.69), 216 (4.68), 259 (4.63), 343
1
(3.90), 340 (3.90). H NMR (400 MHz, DMSO-d6): 1.36–1.40
(m, 2H, piperidinyl-H), 1.48–1.53 (m, 4H, piperidinyl-H), 2.47
(br s, 4H, piperidinyl-H), 2.74 (t, 2H, J = 6.0 Hz, CH2N), 4.21
(t, 2H, J = 6.0 Hz, OCH2), 7.22–7.35 (m, 10H, Ar–H), 7.42 (dd,
1H, J = 9.2, 2.8 Hz, 7-H), 7.46 (d, 1H, J = 2.8 Hz, 5-H), 7.96 (d,
1H, J = 9.2 Hz, 8-H), 8.22 (s, 1H, 4-H). 13C NMR (100 MHz,
DMSO-d6): 23.89, 25.53 (2C), 54.43 (2C), 57.19, 66.01, 106.37,
122.67, 127.23, 127.70 (2C), 127.98, 128.29 (2C), 129.50 (2C),
129.74 (2C), 130.21, 134.12, 136.46 (2C), 139.76, 140.30, 142.69,
155.01, 156.79. Anal. calcd for C28H28N2O·0.4 H2O: C 80.89, H
6.98, N 6.74; found: C 80.88; H, 7.02; N, 6.78.
3,3¢-{4,4¢-[6-(3-(Dimethylamino)propoxy)quinoline-2,3-diyl]bis-
(4,1-phenylene)]bis-(oxy)bis(N,N-dimethylpropan-1-amine) (20c).
From 18c and 3-chloro-N,N-dimethyl-propanamine·HCl as de-
scribed for the preparation of 19a. Compound 20c was obtained in
77% yield (0.45 g) as a white oil. Rf 0.32 (MeOH–CH2Cl2/NH4OH
1 : 5 : 0.02). UV (MeOH): lmax nm (log e) 213 (4.77), 223 (4.74), 271
3-(2,3-Diphenylquinolin-6-yloxy)-N,N-dimethylpropan-1-amine
(19c). From 17 and 3-chloro-N,N-dimethyl-propanamine·HCl
as described for the preparation of 19a. Compound 19c was
obtained in 86% yield (0.33 g) as a white oil. Rf 0.53 (MeOH–
CH2Cl2 1 : 10). UV (MeOH): lmax nm (log e) 231 (4.67), 220
1
(4.62), 248 (4.62), 348 (3.92). H NMR (400 MHz, DMSO-d6):
1.79–1.96 (m, 6H, OCH2CH2CH2), 2.13, 2.14 and 2.16 (three s,
18H, NMe2), 2.31–2.42 (m, 6H, CH2N), 3.85–4.00 (m, 4H, OCH2),
4.13 (t, 2H, J = 6.4 Hz, OCH2), 6.81–6.90 (m, 4H, Ar–H), 7.13–
7.16 (m, 2H, Ar–H), 7.27–7.30 (m, 2H, Ar–H), 7.35–7.40 (m, 2H,
5- and 7-H), 7.91 (d, 1H, J = 8.8 Hz, 8-H), 8.15 (s, 1H, 4-H).
13C NMR (100 MHz, DMSO-d6): 26.82, 26.89, 26.91, 45.21 (6C),
55.66, 55.67 (2C), 65.69, 65.72, 66.24, 106.05, 113.60 (2C), 114.29
(2C), 122.25, 127.85, 130.02, 130.57 (2C), 131.04 (2C), 132.06,
132.65, 133.62, 136.13, 142.50, 154.63, 156.67, 157.84, 158.24.
Anal. calcd for C36H48N4O3·1.8 H2O: C 70.05, H 8.43, N 9.08;
found: C 69.92, H 8.24, N 8.97.
1
(4.66), 259 (4.64), 345 (3.91), 340 (3.90). H NMR (400 MHz,
DMSO-d6): 1.95 (quin, 2H, J = 6.8 Hz, OCH2CH2CH2), 2.18
(s, 6H, NMe2), 2.42 (t, 2H, J = 6.8 Hz, CH2N), 4.16 (t, 2H, J =
6.8 Hz, OCH2), 7.23–7.37 (m, 10H, Ar–H), 7.41–7.45 (m, 2H,
5- and 7-H), 7.97 (d, 1H, J = 8.8 Hz, 8-H), 8.26 (s, 1H, 4-H).
13C NMR(100 MHz, DMSO-d6): 26.73, 45.13 (2C), 55.61, 66.27,
106.16, 122.60, 127.16, 127.63 (2C), 127.95, 128.22 (2C), 129.46
(2C), 129.69 (2C), 130.15, 134.05, 136.41 (2C), 139.73, 140.27,
142.61, 154.90, 156.90. Anal. calcd for C26H26N2O·1.2 H2O: C
77.27, H 7.08, N 6.93; found: C 77.15, H 7.17, N 6.92.
Pharmacological methods
6-[2-(Pyrrolidin-1-yl)ethoxy]-2,3-bis{4-[2-(pyrrolidin-1-yl)ethoxy]-
Antiproliferative assay. Cancer cells (Hep G2, Hep 3B, A549,
H1299, MCF-7, MDA-MB-231) were purchased from Biore-
sources Collection and Research Center, Taiwan. Cell lines were
maintained in the same standard medium and grown as a mono-
layer in DMEM (Gibco, USA) and supplemented with 10% fetal
bovine serum (FBS) and antibiotics i.e. 100 IU mL-1 penicillin,
0.1 mg mL-1 streptomycin and 0.25 mg mL-1 amphotericin. Culture
was maintained at 37 ◦C with 5% CO2 in a humidified atmosphere.
Cells (5 ¥ 103 cells well-1) were treated as indicated for 72 h
in medium containing 10% FBS. Cell viability was quanti-
fied with the use of sodium 3¢-[1-(phenylamino-carbonyl)-3,4-
tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate
(XTT) colorimetric assay (Biological Industries, Beit-Haemek,
Israel). XTT labeling reagent (1 mg mL-1) was mixed with electron-
coupling reagent, following the manufacturer’s instructions, and
50 mL of the mixture was added directly to the cells. The plates
were further incubated at 37 ◦C for 4 h. Color was measured
spectrophotometrically in a microtiter plate reader at 492 nm and
used as a relative measure of viable cell number. The number
of viable cells following treatment was compared to solvent and
untreated control cells and used to determine the percentage of
control growth as (Abtreated/Abcontrol) ¥ 100, where Ab represents
the mean absorbance (n = 3). The concentration that killed 50%
of cells (GI50) was determined from the linear portion of the curve
phenyl}quinoline
(20a). From
18
and
N-(2-
chloroethyl)pyrrolidine·HCl as described for the preparation of
19a. Compound 20a was obtained in 80% yield (0.50 g) as a white
oil. Rf 0.53 (MeOH–CH2Cl2/NH4OH 1 : 5 : 0.02). UV (MeOH):
lmax nm (log e) 213 (4.76), 270 (4.55), 247 (4.54), 347 (3.84),
1
340 (3.81). H NMR (400 MHz, DMSO-d6): 1.62-1.68 (m, 12H,
pyrrolidinyl-H), 2.45–2.53 (m, 12H, pyrrolidinyl-H), 2.72–2.76
(m, 4H, CH2N), 2.83 (t, 2H, J = 5.6 Hz, CH2N), 3.99–4.03 (m,
4H, OCH2), 4.17 (t, 2H, J = 5.6 Hz, OCH2), 6.79–6.88 (m, 4H,
Ar–H), 7.11–7.14 (m, 2H, Ar–H), 7.26–7.28 (m, 2H, Ar–H),
7.34–7.37 (m, 2H, 5- and 7-H), 7.90 (d, 1H, J = 8.8 Hz, 8-H), 8.09
(s, 1H, 4-H). 13C NMR (100 MHz, DMSO-d6): 23.14 (4C), 23.16
(2C), 54.02 (4C), 54.22 (2C), 54.31 (2C), 54.34, 66.65 (2C), 67.11,
106.08, 113.60 (2C), 114.29 (2C), 122.23, 127.82, 130.06, 130.55
(2C), 131.05 (2C), 132.11, 132.70, 133.60, 136.12, 142.55, 154.61,
156.51, 157.70, 158.10. Anal. calcd for C39H48N4O3·1.1 H2O: C
73.12, H 7.90, N, 8.74; found: C 72.83, H 8.17, N 8.64.
6-[2-(Piperidin-1-yl)ethoxy]-2,3-bis{4-[2-(piperidin-1-yl)-ethoxy]-
phenyl}quinoline
(20b). From
18
and
N-(2-
chloroethyl)piperidine·HCl as described for the preparation
of 19a. Compound 20b was obtained in 86% yield (0.33 g) as
a white oil. Rf 0.40 (MeOH–CH2Cl2/NH4OH 1 : 5 : 0.01). UV
(MeOH): lmax nm (log e) 213 (4.80), 224 (4.77), 246 (4.59), 270
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by calculating the concentration of agent that reduced absorbance
in treated cells, compared to control cells, by 50%.23
Bax, Bad and PARP antibodies were used at a 1 : 1000 dilution as
the primary antibodies, while horseradish peroxidase-conjugated
horse anti-rabbit IgG (Vector Laboratories, Burlingame, CA,
USA) was used at a 1 : 5000 dilution as the secondary antibody.
The membrane was then exposed to X-ray film. Protein bands were
detected using the enhanced chemiluminescence blotting detection
system (Amersham, USA).
Cell cycle analysis. MDA-MB-231 cells treated with DMSO
and 16b at different concentrations (1.0, 5.0, 10.0 mM) for 12 or
24 h were harvested, rinsed in PBS, resuspended and fixed in 70%
ethanol and stored at -20 ◦C in fixation buffer until ready for
analysis. Then the pellets were suspended in 1 mL of propidium
iodide (PI) solution containing 20 mg mL-1 of PI, 0.2 mg mL-1
RNase, and 0.1% (v/v) Triton X-100. Cell samples were incubated
at room temperature in the dark for at least 30 min and analyzed by
a flow cytometer (Coulter Epics). Data recording was made using
Epics software and cell cycle data were analyzed using Multicycle
software (Coulter).
Acknowledgements
Financial support of this work by the National Science Council of
the Republic of China is gratefully acknowledged. We also thank
National Center for High-Performance Computing for providing
computer resources and chemical database services.
Immunofluorescenceanalysis. MDA-MB-231cells wereseeded
on cover glasses in 6-well plates with 16b (1.0, 5.0, 10.0 mM)
treatment for 24 h. After incubation, cells were washed with 1X
PBS twice and fixed in 4% paraformaldehyde for 1 h. Then, cells
were washed with PBS containing 0.1 M glycine for 5 min and
permibilized with solution containing 2% FBS and 0.4% Triton
X-100 in PBS at room temperature for 15 min. After permibi-
lization, cells were stained with b-tubulin monoclonal antibody
(Santa Cruza 1 : 1000) at 4 ◦C overnight. After primary antibody
incubation, cells were washed with PBS containing 0.2% Triton
X-100 three times, and stained with fluorescein isothiocyanate-
conjugated anti-mouse IgG antibody (Santa Cruza, 1 : 200 diluted)
at room temperature for 1 h. Finally, cells were washed with
PBS and stained with DAPI (0.1 mg mL-1) for 5 min at room
temperature in the dark. The excess DAPI solution was removed
followed by washing with PBS twice. Samples were mounted before
analyzing under a fluorescence microscope.
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