Synthesis and cytotoxic evaluation of certain 4-anilino-2-phenylquinoline derivatives

Article abstract of DOI:10.1016/j.ejmech.2005.03.008

The present report describes the synthesis and cell growth inhibition of certain 4-anilino-2-phenylquinoline derivatives. 4-(4-Acetylphenylamino)-6- methoxy-2-phenylquinoline (11), its oxime 15a, and its methyloxime 15b, exhibited significant cytotoxicity

Full text of DOI:10.1016/j.ejmech.2005.03.008

European Journal of Medicinal Chemistry 40 (2005) 792–797
www.elsevier.com/locate/ejmech
Original article
Synthesis and cytotoxic evaluation of certain
4-anilino-2-phenylquinoline derivatives
Yue-Ling Zhao a,b,Yeh-Long Chen a, Feng-Shuo Chang a, Cherng-Chyi Tzeng a,*
a Faculty of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung City, Taiwan, ROC
b Graduate Institute of Pharmaceutical Sciences, College of Pharmacy, Kaohsiung Medical University, Kaohsiung City, Taiwan, ROC
Received 21 June 2004; received in revised form 11 February 2005; accepted 10 March 2005
Available online 20 April 2005
Abstract
The present report describes the synthesis and cell growth inhibition of certain 4-anilino-2-phenylquinoline derivatives. 4-(4-
Acetylphenylamino)-6-methoxy-2-phenylquinoline (11), its oxime 15a, and its methyloxime 15b, exhibited significant cytotoxicity against
all 60 cancer cells with mean GI50 values of 3.89, 3.02, and 3.89 µM, respectively, while 4-(4-acetylanilino)-6-methoxy-2-phenylquinoline-
3-carboxylic acid (9) and its 3-carboxylic acid congeners 13a, 13b, 14a, and 14b were inactive, indicated free carboxylic acid at C(3) position
is unfavorable. The steric hindrance exerted by the 3-carboxylate in 9, 13, and 14 may prevent the adjacent phenyl ring to lie coplanar with
quinoline, which leads to the devoid of cytotoxicity. The comparable cytotoxicity of oxime 15a, methyloxime 15b, and the ketone precursor
11 implied a hydrogen-bonding accepting group at C(4) position of 4-anilino-moiety is crucial for cytotoxicity. Among these compounds, 11
is especially active against the growth of certain solid cancer cells such as NCI-H226 (non-small cell lung cancer), MDA-MB-231/ATCC
(breast cancer), and SF-295 (CNS cancer) with GI50 values of 0.94, 0.04, and < 0.01 µM respectively.
© 2005 Elsevier SAS. All rights reserved.
Keywords: 4-Anilino-2-phenylquinoline derivatives; Cytotoxic activity; Anticancer agents
1. Introduction
acridine with its isosteric 2-phenylquinoline ring, which can
be considered as an aza-analogue of antitumor
2-phenylnaphthalene skeleton, which consists of a large num-
ber of antitumor compounds [14–17]. A 2-phenyl derivative
of quinoline-8-carboxamide had been shown to possess DNA-
binding capability and a broad-spectrum activity in both leu-
kemia and solid-tumor assays [15]. Certain 2-phenylquinoline
and 2-phenylquinolone derivatives were also proved to pos-
sess potent antitumor activities [16,17]. Recently, we have
synthesized certain bifunctional antitumor agents consisting
of the alkylating a-methylene-c-butyrolactone and the poten-
tial DNA-intercalating carrier such as flavone, xanthone, car-
bazole, and dibenzofuran [18]. These agents were evaluated
for their cytotoxicities on the ground that through the inter-
calation, the a-methylene-c-butyrolactone can specifically
alkylate DNA molecule. The results were interesting because
flavone derivatives were found to be more cytotoxic than their
isomeric xanthone counterparts. Although the flavone skel-
eton is not a system with three fused aromatic rings required
for a minimal DNA-intercalating ligand, its third phenyl ring
Acridine derivatives, especially 9-anilinoacridines have
been extensively studied as potential chemotherapeutic agents
due to their capability of intercalating DNA leading to the
inhibition of mammalian topoisomerase II [1–9]. Among
them, 4′-(9-acridinylamino)methanesulfonyl-m-anisidine
(amsacrine, m-AMSA), has been specifically relevant and has
become a useful clinical drug for the treatment of leukemia
and
lymphoma
[10–13].
3-(9-Acridinylamino)-5-
(hydroxymethyl)aniline (AHMA) was found to be superior
to m-AMSA against the growth of certain solid tumors such
as mammary adenocarcinoma, melanoma, and Lewis lung car-
cinoma in mice [7]. These studies, however, were focused
only on the 9-anilinoacridine skeleton, with wide varieties of
substituents on anilino and/or acridine chromophore. No
attempt has been carried out concerning the replacement of
* Corresponding author. Tel.: +886 7 312 1101x6985; fax: +886 7 312
5339.
E-mail address: tzengch@kmu.edu.tw (C.-C. Tzeng).
0223-5234/$ - see front matter © 2005 Elsevier SAS. All rights reserved.
doi:10.1016/j.ejmech.2005.03.008

Y.-L. Zhao et al. / European Journal of Medicinal Chemistry 40 (2005) 792–797
793
10. Treatment of 3 with 1 N NaOH followed by 3 N HCl
provided 6-methoxy-2-phenyl-1H-quinolin-4-one (4), which
was
chlorinated
to
give
4-chloro-6-methoxy-2-
phenylquinoline (6). Its reaction with substituted anilines
afforded 4-(4-acetylanilino)-6-methoxy-2-phenylquinoline
(11) and its 3-substituted isomer 12. Reaction of 9 with
NH2OH·HCl gave exclusively (E)-oxime 13a in 80% yield.
The configuration of the oxime moiety was determined by
through-space nuclear Overhauser effect spectroscopy
(NOESY), which revealed coupling connectivity to CH3 pro-
tons. Accordingly, 15a was obtained from 11 by the treat-
ment with NH2OH·HCl. Reaction of 9 and 11 with
NH2OMe·HCl provided (E)-methyloxime 13b and 15b
respectively. Compounds 14a and 14b, 16a and 16b were
obtained, respectively, from 10 to 12 by the same reaction
sequences.
3. Pharmacological results and discussion
All compounds were evaluated in vitro against a three-cell
line panel consisting of MCF7 (Breast), NCI-H460 (Lung),
and SF-268 (CNS) [21]. Results from Table 1 indicated all
the 3-carboxylic acid derivatives 9, 13a, 13b, 14a, and 14b
are inactive. The steric hindrance exerted by the 3-carboxylate
at C(3) of the quinoline moiety may prevent the adjacent phe-
nyl ring to lie coplanar with bicyclic chromophore, which
leads to devoid of cytotoxicity. Those active compounds were
evaluated in the full panel of 60 human tumor cell lines derived
from nine cancer cell types (leukemia, non-small cell lung
cancer, colon cancer, CNS cancer, melanoma, ovarian can-
cer, renal cancer, prostate cancer, and breast cancer). For each
compound, dose-response curves for each cell line were mea-
sured with five different drug concentration, the concentra-
tion causing 50% cell growth inhibition (GI50) compared with
the control were calculated [22]. The 4-COMe group is more
active than their respective 3-substituented couterparts (11,
mean GI50 = 3.89 µM; 12, 9.12 µM). The same cytotoxic SAR
was observed for oxime (15a, 3.02 µM; 16a, 8.51 µM) and
methyloxime derivatives (15b, 3.89 µM; 16b, 8.32 µM) in
which 4-substituted anilino derivatives are preferred. Among
these substituted moieties, the cytotoxicity of oxime (15a,
3.02 µM), methyloxime (15b, 3.89 µM), and their ketone pre-
cursor (11, 3.89 µM) are comparable indicated, a hydrogen-
bonding accepting group at C(4) position of 4-anilino-
moiety is crucial for cytotoxicity. The same cytotoxic SAR
was observed for 3-substituted anilino derivatives in which
the cytotoxicity of 16a, (8.51 µM), 16b, (8.32 µM), and 12,
(9.12 µM) are comparable.
Scheme 1. (i) p-anisidine, K2CO3, DMF; (ii) Ph2O, 230–250 °C; (iii) 1 N
NaOH, 20% HCl; (iv) POCl3; (v) 3- or 4-acetophenone, pyridine, EtOH;
(vi) 1 N NaOH, EtOH; (vii) NH2OR HCl, K2CO3, EtOh.
is appended at C(2), which can accommodate itself in a vir-
tually coplanar fashion to the chromophore [19].
Thus, we described herein the preparation and cell growth
inhibition of certain 4-anilino-2-phenylquinoline derivatives
whose structures belong to the common structural pattern of
2-phenylnaphthalene. Their oxime, methyloxime, and
3-carboxylate derivatives were also synthesized for evalua-
tion. We expect oxime (H-bonding donor) and methyloxime
(H-bonding acceptor) to form hydrogen bonding with DNA
molecule during the intercalation process of 4-anilino-2-
phenylquinoline while 3-carboxylate improves water solubil-
ity.
2. Chemistry
The preparation of 4-anilino-2-phenylquinoline and its
3-carboxylate derivatives is illustrated in the Scheme 1. Reac-
tion of ethyl 3-chloro-2-(ethoxycarbonyl)-3-phenylpropenoate
(1) [20] with p-anisidine gave diethyl 3-(4-methoxyanilino)-
phenylidenemalonate (2) which was thermal cyclized to afford
ethyl 6-methoxy-4-oxo-2-phenyl-1,4-dihydroquinoline-3-
carboxylate (3). Chlorinated of 3 with POCl3 gave ethyl
4-chloro-6-methoxy-2-phenylquinoline-3-carboxylate (5)
which was treated with substituted anilines to give ethyl 4-(4-
acetylanilino)-6-methoxy-2-phenylquinoline-3-carboxylate
(7) and its 3-substituted isomer 8. Hydrolysis of 7 and 8 with
1 N NaOH afforded their respective 3-caboxylic acid 9 and
Representative results of the individual cell cytotoxicity
are summarized in Table 2. Compound 11 is especially active
against the growth of certain solid cancer cells such as NCI-
H226 (non-small cell lung cancer), MDA-MB-231/ATCC
(breast cancer), and SF-295 (CNS cancer) with GI50 values
of 0.94, 0.04, and < 0.01 µM respectively. Compounds 15a
and 15b also showed selectivity against these three cancer

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Y.-L. Zhao et al. / European Journal of Medicinal Chemistry 40 (2005) 792–797
Table 1
evaluated for their cytotoxic activities. The preliminary cyto-
toxic assay indicated 4-substituted-4-anilino-derivatives are
more active than their respective 3-substituted-4-anilino-
counterparts, indicated position of substitution plays an impor-
tant role in cytotoxicity. Substitution of the carboxylic acid at
C(3) prevent the adjacent phenyl ring to lie coplanar with
quinoline, which leads to devoid of cytotoxicity.
Preliminary cytotoxic assay of 4-anilino-2-phenylquinoline derivatives
Compounds
Growth percentages a
Mean GI50
(µM) b
NCI-H460
MCF7
SF-268
(Lung)
(Breast)
84
7
(CNS)
133
27
9
11
12
111
2
nd c
3.89
9.12
nd
nd b
nd
2
1
1
13a
13b
14a
14b
15a
15b
16a
16b
106
100
97
85
3
75
60
84
73
12
13
15
2
118
111
94
5. Experimental protocols
72
nd
32
3.02
3.89
8.51
8.32
5.1. General
5
8
1
10
Melting points (m.p.) were determined on a Electrother-
mal IA9100 m.p. apparatus and are uncorrected. Nuclear mag-
netic resonance (1H and 13C) spectra were recorded on a
Varian Gemini 200 spectrometer or Varian-Unity-400 spec-
trometer. Chemical shifts were expressed in parts per million
(d) with tetramethylsilane (TMS) as an internal standard. TLC
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 Chung-Hsing Univer-
sity using Heraeus CHN-O Rapid EA.
2
1
a 4-Anilino-2-phenylquinoline derivatives were evaluated in vitro against
a three-cell line panel consisting of MCF7 (Breast), NCI-H460 (Lung), and
SF-268 (CNS). In this protocol, each cell line is inoculated and preincubated
on a microtiter plate. Test agents are then added at a single concentration
(100 µM) and the culture incubated for 48 h. End-point determinations are
made with alamar blue [21]. Results for each test agent are reported as the
percent of growth of the treated cells when compared to the untreated control
cells. Compounds which reduced the growth of any one of the cell lines to
32% or less are passed on for evaluation in the full panel of 60 cell lines over
a 5-log dose range [22].
b Mean values over all 60 cell lines tested. Theses cell lines are: leukemia
(CCRF-CEM, HL-60 (TB), K-562, MOLT-4, PRMI-8226, and SR); non-
small cell lung cancer (A549/ATCC, EKVX, HOP-62, HOP-92, NCI-H226,
NCI-H23, NCI-H322 M, and NCI-H522); colon cancer (COLC 205, HCC-
2998, HCT-116, HCT-15, HT29, KM12, and SW-620); CNS cancer (SF-
268, SF-295, SF-539, SNB-19, SNB-75, and U251); melanoma (LOX IMVI,
MALME-3 M, M14, SK-MEL-2, SK-MEL-28, SK-MEL-5, and UACC-
257); ovarian cancer (IGROV1, OVCAR-3, OVCAR-4, OVCAR-5,
OVCAR-8, and SK-OV-3); renal cancer (786-0,A498,ACHN, CAKI-1, RXF
393, SN12C, TK-10, and UO-31); prostate cancer (PC-3 and DU-145); and
breast cancer (MCF7, MCF7/ADR-RES, MDA-MB-231/ATCC, HS 578T,
MDA-MB-435, MDA-N and T-47D).
5.1.1. Diethyl 3-(4-methoxyanilino)phenylidenemalonate
(2)
A
mixture of ethyl 3-chloro-2-(ethoxycarbonyl)-3-
phenylpropenoate (1) (2.84 g, 10 mmol), p-anisidine (1.48 g,
12 mmol), K2CO3 (1.95 g, 14 mmol) and dry DMF (50 ml)
was heated in 140 °C for 3 h (TLC monitoring,
CH2Cl2/MeOH 20:1). The mixture was evaporated under
reduced pressure and then H2O (100 ml) was added. This
aqueous mixture was extracted with CH2Cl2 (100 ml × 3),
dried (MgSO4), and concentrated to yield a brown oil. The
crude oil was purified by flash column chromatography (FC,
silica gel; using CH2Cl2 as the eluent) to give 2 (2.88 g, 78%)
as a yellow oil. 1H NMR (CDCl3) d: 0.80 (t, 3H, J = 7.2 Hz,
OCH2CH3), 1.32 (t, 3H, J = 7.2 Hz, OCH2CH3), 3.67 (s, 3H,
OCH3), 3.76 (q, 2H, J = 7.2 Hz, OCH2CH3), 4.26 (q, 2H,
J = 7.2 Hz, OCH2CH3), 6.61 (m, 4H, Ar–H), 7.24 (m, 5H,
Ar–H), 11.09 (br s, 1H, NH). 13C NMR (CDCl3) d: 13.36,
14.25, 55.09, 59.94, 60.30, 96.34, 113.70 (2C), 125.47 (2C),
128.04 (2C), 128.56 (2C), 129.13, 131.70, 133.93, 156.55,
161.85, 167.49, 168.17. Anal. Calcd. for C21H23NO5: C,
68.28; H, 6.28; N, 3.79. Found: C, 68.21; H, 6.29; N, 3.81.
c Not determined.
cells with GI50 values of less than 2.25 µM in each case.
Among these cancer cells tested, MDA-MB-231/ATCC was
found to be very sensitive to 11, 15a, and 15b with GI50 val-
ues of 0.04, 0.73, and 1.23 µM respectively.
4. Conclusion
A number of 3-substituted-4-anilino- and 4-substituted-4-
anilino-2-phenylquinoline derivatives were synthesized and
Table 2
In vitro cytotoxic assay (GI50, µM) of selected 4-anilino-2-phenylquinoline
derivatives
Cell line
Compounds
15a 15b
11
12
16a
16b
5.1.2. Ethyl 6-methoxy-4-oxo-2-phenyl-1,4-
dihydroquinoline-3-carboxylate (3)
RPMI-8226
NCI-H226
COLO 205
SF-295
1.72 33.2
0.94 16.1
2.16 2.79 4.89 3.12
2.05 2.25 3.18 15.7
A solution of 2 (3.70 g, 10 mmol) in Ph2O (30 ml) was
heated at 230–250 °C for 1 h (TLC monitoring,
CH2Cl2/MeOH 5:1). The reaction mixture was cooled and
then n-hexane (100 ml) was added. The resulting precipitate
was collected and crystallized from MeOH to give 3 (2.65 g,
82%) as a white powder. M.p. 223–224 °C. 1H NMR (TFA-d)
d: 0.80 (t, 3H, J = 7.2 Hz, OCH2CH3), 4.00 (s, 3H, OCH3),
16.4
6.58 4.91 7.02 21.4 33.1
<0.01 12.7
29.5 12.4
16.1 19.7
1.53 2.02 2.05 3.82
3.39 29.4 57.7 28.6
SK-MEL-28
SK-OV-3
2.32 15.2
6.65 29.2
ACHN
2.54 5.78 14.0
14.1 13.2
0.04 9.65 0.73 1.23 2.54 3.49
3.27 7.30 14.1
DU-145
1.57 5.36 6.46 12.0
MDA-MB-231/ATCC

Y.-L. Zhao et al. / European Journal of Medicinal Chemistry 40 (2005) 792–797
795
4.15 (q, 2H, J = 7.2 Hz, OCH2CH3), 7.40–7.92 (m, 8H,Ar–H).
13C NMR (TFA-d) d: 13.58, 57.60, 66.33, 104.89, 123.37,
129.36, 129.80 (2C), 130.92 (2C), 132.09, 132.36, 133.97,
134.78, 136.20, 159.04, 163.09, 171.19, 175.16.Anal. Calcd.
for C19H17NO4: C, 70.58; H, 5.30; N, 4.33. Found: C, 70.42;
H, 5.34; N, 4.37.
(20 ml) was refluxed for 3 h (TLC monitoring, CH2Cl2/MeOH
20:1). The mixture was then cooled and evaporated in vacuo
to yield a yellow residue, treated with H2O (50 ml), and the
resulting precipitate was filtered and washed with H2O. The
crude product was purified by FC (using CH2Cl2 as the elu-
ent) to give 7 (0.50 g, 58%) as a yellow powder. M.p. 156–
1
157 °C. H NMR (CDCl3) d: 0.76 (t, 3H, J = 7.2 Hz,
5.1.3. 6-Methoxy-2-phenyl-1H-quinolin-4-one (4)
OCH2CH3), 2.54 (s, 3H, C(=O)CH3), 3.56 (s, 3H, OCH3),
3.97 (q, 2H, J = 7.2 Hz, OCH2CH3), 6.84 (m, 2H, Ar–H),
6.92 (d, 1H, J = 2.4 Hz, H-5), 7.43 (m, 4H, Ar–H) 7.62 (m,
2H,Ar–H), 7.86 (m, 2H,Ar–H), 8.05 (d, 1H, J = 9.0 Hz, H-8),
8.37 (br s, 1H, NH). 13C NMR (CDCl3) d: 13.09, 26.29, 55.33,
61.72, 103.42, 113.63, 117.43 (2C), 121.33, 124.05, 128.13
(2C), 128.29 (2C), 129.90 (2C), 130.64, 130.72, 131.65,
141.23, 144.73, 147.57, 155.95, 157.06, 157.32, 168.87,
196.50. Anal. Calcd. for C27H24N2O4·0.25H2O: C, 72.87; H,
5.88; N, 6.30. Found: C, 72.90; H, 5.62; N, 6.44.
To a suspension of 3 (3.23 g, 10 mmol) in EtOH (20 ml)
was added a solution of 1 N NaOH (40 ml) and the mixture
heated at reflux for 6 h The mixture was evaporated under
reduced pressure and then H2O (200 ml) was added and neu-
tralized with 20% HCl solution. The resulting precipitate was
collected, refluxed with 20% HCl solution (200 ml) for 6 h
(TLC monitoring, CH2Cl2/MeOH 5:1). The mixture was
cooled to room temperature and the precipitate was col-
lected, washed with H2O, and then crystallized from MeOH
to give 4 (2.13 g, 85%) as a white powder. M.p. 283–285 °C
1
(lit. [11], 302–304 °C). H NMR (TFA-d) d: 4.31 (s, 3H,
5.1.7. Ethyl 4-(3-acetylanilino)-6-methoxy-2-
phenylquinoline-3-carboxylate (8)
OCH3), 7.78–8.11 (m, 8H, Ar–H), 8.34 (d, 1H, J = 8.0 Hz,
H-8). 13C NMR (TFA-d) d: 57.56, 103.86, 106.15, 122.97,
123.20, 129.48 (2C), 130.22, 132.05 (2C), 132.89, 135.25,
137.40, 156.42, 161.75, 169.99.
Prepared from 5 and 3-aminoacetophenone by the same
procedure as described for 7. Compound 8 in was obtained in
a 52% yield. M.p. 128–129 °C. 1H NMR (CDCl3) d: 0.74 (t,
3H, J = 7.2 Hz, OCH2CH3), 2.54 (s, 3H, C(=O)CH3), 3.50
(s, 3H, OCH3), 3.90 (q, 2H, J = 7.2 Hz, OCH2CH3), 6.96 (d,
1H, J = 2.2 Hz, H-5), 7.08 (dd, 1H, J = 9.2, 2.2 Hz, H-7),
7.31–7.47 (m, 5H, Ar–H), 7.61 (m, 4H, Ar–H), 8.12 (d, 1H,
J = 9.2 Hz, H-8), 8.80 (br s, 1H, NH). 13C NMR (CDCl3) d:
13.05, 26.73, 55.25, 61.58, 103.86, 115.02, 119.23, 120.42,
122.51, 123.93, 124.05, 128.16 (2C), 128.25 (2C), 128.34,
129.21, 131.16, 138.01, 141.14, 143.32, 144.13, 146.50,
156.13, 156.97, 168.98, 197.60. Anal. Calcd. for
C27H24N2O4·0.25H2O: C, 72.87; H, 5.88; N, 6.30. Found: C,
72.84; H, 5.58; N, 6.20.
5.1.4. Ethyl 4-chloro-6-methoxy-2-phenylquinoline-3-
carboxylate (5)
A mixture of 3 (3.23 g, 10 mmol) and POCl3 (30 ml) was
refluxed for 12 h (TLC monitoring, CH2Cl2/MeOH 10:1).
After cooling, the mixture was slowly poured in ice-water
(150 ml), neutralized with NH4OH. This aqueous mixture was
extracted with CH2Cl2 (100 ml × 3), dried (MgSO4), and con-
centrated to yield yellow solid. The crude product was puri-
fied by FC (using CH2Cl2 as the eluent) to give 5 (2.67 g,
78%) as a yellow needle crystals. M.p. 112–113 °C. 1H NMR
(CDCl3) d: 1.10 (t, 3H, J = 7.2 Hz, OCH2CH3), 3.90 (s, 3H,
OCH3), 4.25 (q, 2H, J = 7.2 Hz, OCH2CH3), 7.37–7.46 (m,
5H, Ar–H), 7.69 (m, 2H, Ar–H), 8.00 (d, 1H, J = 10.2 Hz,
H-8). 13C NMR (CDCl3) d: 13.54, 55.51, 61.89, 101.57,
124.08, 125.19, 126.90, 128.23 (4C), 128.77, 131.25, 138.34,
139.22, 143.93, 153.40, 158.92, 166.29. Anal. Calcd. for
C19H16ClNO3: C, 66.77; H, 4.72; N, 4.10. Found: C, 66.61;
H, 4.77; N, 4.15.
5.1.8. 4-(4-Acetylanilino)-6-methoxy-2-phenylquinoline-3-
carboxylic acid (9)
To a suspension of 7 (0.88 g, 2 mmol) in EtOH (20 ml)
was added 1 N NaOH solution (40 ml) and the mixture was
heated at reflux for 2 h (TLC monitoring, CH2Cl2/MeOH
10:1). The mixture was cooled, evaporated under reduced
pressure and then H2O (200 ml) was added and neutralized
with 20% HCl solution. The resulting precipitate was col-
lected, washed with H2O, and then crystallized from MeOH
to give 9 (0.58 g, 71%). M.p. 198–199 °C. 1H NMR (DMSO-
d6) d: 2.57 (s, 3H, C(=O)CH3), 4.00 (s, 3H, OCH3), 7.44 (m,
2H,Ar–H), 7.63 (m, 5H,Ar–H), 7.77 (dd, 1H, J = 9.2, 2.6 Hz,
H-7), 7.97 (m, 2H, Ar–H), 8.15 (d, 1H, J = 9.2 Hz, H-8), 8.22
(d, 1H, J = 2.6 Hz, H-5), 11.11 (br s, 1H, NH). 13C NMR
(DMSO-d6) d: 26.68, 56.64, 106.54, 112.27 (2C), 117.99 (2C),
122.95, 123.71, 128.41 (2C), 129.02 (2C), 129.36, 132.67,
132.79, 133.48, 133.97, 151.73, 157.21, 157.99, 158.75,
5.1.5. 4-Chloro-6-methoxy-2-phenylquinoline (6)
Prepared from 4 by the same procedure as described for 5.
Compound 6 was obtained in a 92% yield. M.p. 103–104 °C.
1H NMR (DMSO-d6) d: 3.93 (s, 3H, OCH3), 7.38 (d, 1H,
J = 2.8 Hz, H-5), 7.54 (m, 4H, Ar–H and H-7), 8.20 (m, 3H,
Ar–H and H-8), 8.34 (s, 1H, H-3). 13C NMR (DMSO-d6) d:
55.88, 101.67, 119.65, 124.28, 125.95, 127.59 (2C), 128.93
(2C), 129.78, 130.33, 135.97, 142.24, 142.42, 153.17, 158.74.
Anal. Calcd. for C16H12ClNO: C, 71.25; H, 4.48; N, 5.19.
Found: C, 71.47; H, 4.58; N, 5.30.
5.1.6. Ethyl 4-(4-acetylanilino)-6-methoxy-2-
phenylquinoline-3-carboxylate (7)
158.83,
165.25,
196.80.
Anal.
Calcd.
for
C25H20N2O4·HCl·1.6H2O: C, 62.85; H, 4.86; N, 5.87. Found:
C, 62.65; H, 5.20; N, 5.51.
A mixture of 5 (0.69 g, 2 mmol), 4-aminoacetophenone
(0.27 g, 2 mmol), and pyridine (0.5 ml) in ethoxyethanol

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Y.-L. Zhao et al. / European Journal of Medicinal Chemistry 40 (2005) 792–797
5.1.9. 4-(3-Acetylanilino)-6-methoxy-2-phenylquinoline-3-
carboxylic acid (10)
d: 2.08 (s, 3H, C(=N)CH3), 3.61 (s, 3H, OCH3), 6.80 (m, 2H,
Ar–H), 7.19 (d, 1H, J = 2.2 Hz, H-5), 7.46 (m, 7H, Ar–H),
7.64 (m, 3H, Ar–H), 7.96 (d, 1H, J = 9.0 Hz, H-8), 8.79 (br s,
1H, NH), 10.97 (br s, 1H, NOH). 13C NMR (DMSO-d6) d:
11.57, 55.48, 103.20, 117.16 (2C), 121.56, 122.84, 122.99,
126.38 (2C), 128.21 (2C), 128.49 (2C), 129.19, 129.78,
131.11, 140.41, 143.62, 143.75, 145.18, 152.80, 154.40,
157.22, 169.11. Anal. Calcd. for C25H21N3O4·0.9H2O: C,
68.09; H, 5.26; N, 9.53. Found: C, 68.39; H, 5.13; N,
9.16.
Prepared from 8 by the same procedure as described for 9.
Compound 10 was obtained in a 68% yield. M.p. 225–
1
226 °C. H NMR (DMSO-d6) d: 2.55 (s, 3H, C(=O)CH3),
4.00 (s, 3H, OCH3), 7.60 (m, 7H,Ar–H), 7.74 (dd, 1H, J = 9.2,
1.8 Hz, H-7), 7.89 (m, 2H, Ar–H), 8.13 (d, 1H, J = 9.2 Hz,
H-8), 8.29 (d, 1H, J = 1.8 Hz, H-5), 11.03 (br s, 1H, NH).
13C NMR (DMSO-d6) d: 26.86, 56.67, 103.58, 111.33,
118.12, 120.28, 122.40, 124.06, 126.20, 128.40 (2C), 128.93
(2C), 130.73, 132.58, 133.20, 137.25, 139.29, 150.80, 151.40,
158.06, 158.66, 158.81, 165.45, 197.41. Anal. Calcd. for
C25H20N2O4·H2O: C, 69.76; H, 5.15; N, 6.51. Found: C,
70.08; H, 5.13; N, 6.53.
5.1.13. (E)-6-Methoxy-4-[4-(1-methoxyiminoethyl)anilino]-
2-phenylquinoline-3-carboxylic acid (13b)
Prepared from 9 and NH2OCH3·HCl by the same proce-
dure as described for 13a. Compound 13b was obtained in a
84% yield. M.p. 225–226 °C. 1H NMR (DMSO-d6) d: 2.11
(s, 3H, C(=N)CH3), 3.68 (s, 3H, OCH3), 3.87 (s, 3H, NOCH3),
6.80 (m, 2H, Ar–H), 7.22 (d, 1H, J = 2.8 Hz, H-5), 7.50 (m,
6H,Ar–H), 7.69 (m, 2H,Ar–H), 8.00 (d, 1H, J = 9.2 Hz, H-8),
8.89 (br s, 1H, NH). 13C NMR (DMSO-d6) d: 12.19, 55.45,
61.46, 103.11, 116.85 (2C), 121.97, 122.85, 123.17, 126.72
(2C), 127.78, 128.19 (2C), 128.49 (2C), 128.57, 131.16,
140.36, 143.48, 143.94, 145.84, 153.82, 154.33, 157.32,
169.02. Anal. Calcd. for C26H23N3O4: C, 70.73; H, 5.25; N,
9.52. Found: C, 70.43; H, 5.45; N, 9.15.
5.1.10. 4-(4-Acetylanilino)-6-methoxy-2-phenylquinoline
(11)
Prepared from 6 and 4-aminoacetophenone by the same
procedure as described for 7. Compound 11 was obtained in
a 62% yield. M.p. 180–181 °C. 1H NMR (DMSO-d6) d: 2.66
(s, 3H, C(=O)CH3), 3.94 (s, 3H, OCH3), 7.15 (s, 1H, 3-H),
7.25 (dd, 1H, J = 9.4, 2.0 Hz, H-7), 7.59 (m, 3H, Ar–H), 7.71
(m, 2H, Ar–H), 7.82 (m, 2H, Ar–H), 8.06 (m, 3H, Ar–H and
H-5), 8.27 (d, 1H, J = 9.4 Hz, H-8), 10.82 (br s, 1H, NH),
13.79 (br s, 1H, HCl). 13C NMR (DMSO-d6) d: 26.29, 56.55,
99.11, 102.26, 118.38, 121.78, 123.82 (2C), 125.65, 127.91
(2C), 129.32 (2C), 130.02 (2C), 131.37, 131.88, 134.80,
142.02, 150.91, 153.10, 153.25, 158.48, 197.42.Anal. Calcd.
for C24H20N2O2·HCl: C, 71.19; H, 5.24; N, 6.92. Found: C,
71.10; H, 5.24; N, 6.92.
5.1.14. (E)-4-[3-(1-Hydroxyiminoethyl)anilino]-6-methoxy-
2-phenylquinoline-3-carboxylic acid (14a)
Prepared from 10 and NH2OH·HCl by the same proce-
dure as described for 13a. Compound 14a was obtained in a
75% yield. M.p. 229–230 °C. 1H NMR (DMSO-d6) d: 2.04
(s, 3H, C(=N)CH3), 3.53 (s, 3H, OCH3), 6.77 (m, 1H, Ar–H),
6.94 (d, 1H, J = 2.8 Hz, H-5), 7.15 (m, 3H, Ar–H), 7.37 (m,
4H,Ar–H), 7.77 (m, 2H,Ar–H), 7.90 (d, 1H, J = 9.0 Hz, H-8),
8.95 (br s, 1H, NH), 11.10 (br s, 1H, NOH). 13C NMR
(DMSO-d6) d: 11.48, 54.99, 103.64, 114.78, 118.02, 118.28,
121.38, 122.00, 125.02, 127.60 (2C), 128.57 (2C), 128.70,
131.10, 137.41, 141.51, 142.57, 143.24, 144.62, 152.74,
5.1.11. 4-(3-Acetylanilino)-6-methoxy-2-phenylquinoline
(12)
Prepared from 6 and 3-aminoacetophenone by the same
procedure as described for 7. Compound 12 was obtained in
a 58% yield. M.p. 129–130 °C. 1H NMR (CDCl3) d: 2.54 (s,
3H, C(=O)CH3), 3.91 (s, 3H, OCH3), 6.85 (s, 1H, H-3), 7.35
(m, 5H,Ar–H), 7.71 (m, 4H,Ar–H), 8.20 (m, 2H,Ar–H), 8.59
(d, 1H, J = 9.2 Hz, H-8), 11.01 (br s, 1H, NH), 14.10 (br s,
1H, HCl). 13C NMR (CDCl3) d: 26.67, 57.06, 98.21, 103.02,
118.42, 122.34, 124.28, 125.57, 126.45, 128.27 (2C), 129.06
(2C), 129.41, 129.99, 131.38, 131.53, 134.30, 138.27, 138.42,
150.64, 153.75, 158.45, 197.01. Anal. Calcd. for
C24H20N2O2·HCl·0.9H2O: C, 68.45; H, 5.50; N, 6.68. Found:
C, 68.14; H, 5.58; N, 6.68.
154.61,
156.12,
170.64.
Anal.
Calcd.
for
C25H21N3O4·HCl·0.5H2O: C, 63.48; H, 5.13; N, 8.88. Found:
C, 63.49; H, 5.23; N, 8.50.
5.1.15. (E)-6-Methoxy-4-[3-(1-methoxyiminoethyl)anilino]-
2-phenylquinoline-3-carboxylic acid (14b)
Prepared from 10 and NH2OCH3·HCl by the same proce-
dure as described for 13a. Compound 14b was obtained in a
72% yield. M.p. 193–194 °C. 1H NMR (DMSO-d6) d: 2.07
(s, 3H, C(=N)CH3), 3.83 and 3.86 (two s, each 3H, OCH3
and NOCH3), 7.24–7.64 (m, 10H,Ar–H), 7.89 (m, 2H,Ar–H),
7.95 (d, 1H, J = 9.2 Hz, H-8), 10.63 (br s, 1H, NH). 13C NMR
(DMSO-d6) d: 12.54, 56.50, 61.99 103.23, 110.94, 113.11,
118.89, 120.06, 122.33, 125.70, 126.63, 128.92 (2C), 129.69
(2C), 131.30, 132.59, 133.30, 137.02, 138.87, 151.71, 154.29,
158.23, 159.69, 160.42, 166.02. Anal. Calcd. for
C26H23N3O4·0.25 H2O: C, 70.01; H, 5.64; N, 9.42. Found:
C, 70.06; H, 5.41; N, 9.31.
5.1.12. (E)-4-[4-(1-Hydroxyiminoethyl)anilino]-6-methoxy-
2-phenylquinoline-3-carboxylic acid (13a)
A mixture of 9 (206 mg, 0.50 mmol), NH2OH·HCl
(175 mg, 2.50 mmol), and K2CO3 (160 mg, 1.30 mmol) in
EtOH (10 ml) was refluxed for 2 h (TLC monitoring,
CH2Cl2/MeOH 10:1). The mixture was evaporated under
reduced pressure and then H2O (80 ml) was added. The result-
ing precipitate was collected by filtration, washed with H2O,
and then crystallized from MeOH to give 13a (0.17 g, 80%)
as a yellow powder. M.p. 240–241 °C. 1H NMR (DMSO-d6)

Y.-L. Zhao et al. / European Journal of Medicinal Chemistry 40 (2005) 792–797
797
5.1.16. (E)-4-[4-(1-Hydroxyiminoethyl)anilino]-6-methoxy-
2-phenylquinoline (15a)
125.53, 125.77, 128.40 (2C), 129.38 (2C), 130.22, 131.78,
132.37, 134.46, 137.67, 137.76, 150.97, 153.52, 153.67,
158.16.Anal. Calcd. for C25H23N3O2·HCl·0.7H2O: C, 67.23;
H, 5.64; N, 9.41. Found: C, 67.08; H, 5.72; N, 9.38.
Prepared from 11 and NH2OH·HCl by the same procedure
as described for 13a. Compound 15a was obtained in a 75%
yield. M.p. 262–263 °C. 1H NMR (DMSO-d6) d: 2.19 (s, 3H,
C(=N)CH3), 4.00 (s, 3H, OCH3), 7.12 (s, 1H, H-3), 7.60 (m,
5H, Ar–H), 7.87 (m, 4H, Ar–H), 8.21 (m, 3H, Ar–H), 10.72
(br s, 1H, NH), 11.30 (br s, 1H, NOH). 13C NMR (DMSO-
d6) d: 11.45, 56.57, 98.98, 102.80, 118.38, 123.77, 124.25
(2C), 124.80, 126.88 (2C), 128.17 (2C), 129.17 (2C), 131.20,
133.40, 134.72, 135.97, 138.43, 151.34, 152.08, 152.34,
157.83.Anal. Calcd. for C24H21N3O2·HCl·0.7H2O: C, 66.64;
H, 5.59; N, 9.75. Found: C, 66.58; H, 5.51; N, 9.59.
Acknowledgements
Financial support of this work by the National Science
Council of the Republic of China is gratefully acknowl-
edged. We also thank National Cancer Institute (NCI) of the
United States for the anticancer screenings and the National
Center for High-Performance Computing for providing com-
puter resources and chemical database services.
5.1.17. (E)-6-Methoxy-4-[4-(1-methoxyiminoethyl)anilino]-
2-phenylquinoline (15b)
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Prepared from 11 and NH2OCH3·HCl by the same proce-
dure as described for 13a. Compound 15b was obtained in a
76% yield. M.p. 108–109 °C. 1H NMR (DMSO-d6) d: 2.21
(s, 3H, C(=N)CH3), 3.93 and 3.95 (two s, each 3H, OCH3
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5.1.18. (E)-4-[3-(1-Hydroxyiminoethyl)anilino]-6-methoxy-
2-phenylquinoline (16a)
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(s, 3H, C(=N)CH3), 3.95 (s, 3H, OCH3), 7.46 (m, 8H, Ar–H),
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2-phenylquinoline (16b)
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(s, 3H, C(=N)CH3), 3.95 and 4.03 (two s, each 3H, OCH3
and NOCH3), 7.03 (s, 1H, H-3), 7.65 (m, 7H, Ar–H), 7.88
(m, 3H, Ar–H), 8.27 (b rs, 1H, NH), 8.29 (d, 1H, J = 9.2 Hz,
H-8), 10.99 (br s, 1H, HCl). 13C NMR (DMSO-d6) d: 12.45,
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