Discovery of 4-anilinofuro[2,3- b ]quinoline derivatives as selective and orally active compounds against non-small-cell lung cancers

Article abstract of DOI:10.1021/jm200046z

We have reported the preparation and anticancer evaluation of certain 4-anilinofuro[2,3-b]quinolines. However, drawbacks such as lack of selective cytotoxicity, poor oral bioavailability, and poor water solubility exhibited by these compounds prompted us to search for newer derivatives. Among them, (E)-1-(4-(furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone O-2-aminoethyloxime (13a) is selectively active against the growth of NCI-H460 and is highly water-soluble (63 μg/mL). Its hydrochloride salt, 13a?HCl exhibited not only excellent water solubility (1049 μg/mL) but also a high oral bioavailability (57.1%). Compound 13a may cause cancer cell apoptosis through inducing mitotic arrest and mitotic catastrophe mechanism. Xenographic studies indicated the tumor size with 13a?HCl treated nude mice was significantly lower than control. Further evaluation in an orthotopic lung cancer model indicated that 13a?HCl can be absorbed readily through oral administration, distributed to lung tissue, and exhibited significant efficacy in inhibiting the growth of lung cancers.

Full text of DOI:10.1021/jm200046z

ARTICLE
pubs.acs.org/jmc
Discovery of 4-Anilinofuro[2,3-b]quinoline Derivatives as Selective
and Orally Active Compounds against Non-Small-Cell Lung Cancers
Yu-Wen Chen,† Yeh-Long Chen,† Chih-Hua Tseng,† Chih-Chung Liang,† Chia-Ning Yang,§ Yun-Chin Yao,‡
Pei-Jung Lu,*,‡ and Cherng-Chyi Tzeng*,†
†Department of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung City 807, Taiwan
‡Institute of Clinical Medicine, School of Medicine, National Cheng-Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan
§Institute of Biotechnology, National University of Kaohsiung, 700 Kaohsiung University Road, Kaohsiung, Taiwan
ABSTRACT: We have reported the preparation and anticancer evaluation of certain 4-anilinofuro-
[2,3-b]quinolines. However, drawbacks such as lack of selective cytotoxicity, poor oral bioavailability,
and poor water solubility exhibited by these compounds prompted us to search for newer derivatives.
Among them, (E)-1-(4-(furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone O-2-aminoethyloxime
(13a) is selectively active against the growth of NCI-H460 and is highly water-soluble (63 μg/mL).
Its hydrochloride salt, 13a HCl exhibited not only excellent water solubility (1049 μg/mL) but also a
3
high oral bioavailability (57.1%). Compound 13a may cause cancer cell apoptosis through inducing
mitotic arrest and mitotic catastrophe mechanism. Xenographic studies indicated the tumor size with 13a HCl treated nude mice
3
was significantly lower than control. Further evaluation in an orthotopic lung cancer model indicated that 13a HCl can be absorbed
3
readily through oral administration, distributed to lung tissue, and exhibited significant efficacy in inhibiting the growth of lung
cancers.
’ INTRODUCTION
poor oral bioavailability, and poor water solubility exhibited by
compound 1 and its hydroxyimino and methoxyimino deriva-
tives 2 and 3, respectively, prompted us to search for newer
derivatives with better pharmacokinetic profiles and higher water
solubility. In fact, low water solubility and low bioavailability are
frequent problems in drug development, particularly in the area
of anticancer drugs.16ꢀ23
Acridine derivatives, especially 9-anilinoacridines, have been
extensively studied as potential chemotherapeutic agents because
of their capability of intercalating DNA, leading to the inhibition
of mammalian topoisomerase II.1ꢀ10 Among such derivatives,
amsacrine (m-AMSA) has been clinically used for the treatment
of leukemia and lymphoma.1 Further structural modification has
led to the discovery of improved broad spectrum anticancer
agents that were capable of inhibiting the growth of certain
solid tumors such as mammary adenocarcinoma, melanoma, and
Lewis lung carcinoma.9,10 These results prompted us to synthe-
size and evaluate 4-anilinofuro[2,3-b]quinoline derivatives that
can be structurally related to 9-anilinoacridines by isosteric
substitution of a benzene moiety for a furan ring.11ꢀ15 Among
these 4-anilinofuro[2,3-b]quinoline derivatives, 1-[4-(furo[2,
3-b]quinolin-4-ylamino)phenyl]ethanone (1, Chart 1) with a
mean graph midpoint (GI50) of 0.025 μM, was more active than
m-AMSA (GI50 = 0.44 μM) in the NCI’s full panel of 60 human
cancer cells.11 The antiproliferative potency of its hydroxyimino
and methoxyimino derivatives, 2 and 3, respectively, was also
proved to be comparable to that of m-AMSA. Compound 1 had
been selected as a lead compound and was evaluated by flow
cytometric analysis for its effects on cell cycle distributions. Results
indicated that 1 inhibited cell proliferation by the alteration of
cell division and accumulation of cells in the G2/M phase
followed by the cell apoptosis which is similar to microtubule-
targeting agents such as paclitaxel but distinct from that of m-AMSA.
This is interesting because 4-anilinofuro[2,3-b]quinoline deriv-
atives, if proved to be active, could be developed as a new
structural type of potential antimicrotubule drug candidates.
However, some drawbacks such as lack of selective cytotoxicity,
Low water solubility is an intrinsic property of many natural
and synthetic drug candidates and is usually associated with poor
absorption and bioavailability.16,17 Camptothecin (4, Chart 1),
for example, is an antitumor alkaloid isolated from Camptotheca
acuminata.18,19 Its clinical use has been hampered until the recent
structural optimization leading to the discovery of water-soluble
derivatives such as topotecan and irinotecan. The introduction of
aminoalkyl functionalities conferring water solubility to the
quinoline nucleus is therefore one of the most successful strat-
egies for the structural optimization of anticancer drugs.20ꢀ24
-
Combretastatin A-4 is another example of a natural product that
possesses poor water solubility.24ꢀ29 In order to improve its
water solubility and in vivo efficacy, the water-soluble combre-
tastatin A-4 phosphate has been prepared as a prodrug.30
Recently, we have also synthesized certain indenoquinoline
derivatives that bear aminoalkyl side chain as potential anticancer
agents.31ꢀ33 Our results indicated that introduction of the
aminoalkyl side chain on the tetracyclic pharmacophore im-
proved not only water solubility but also anticancer potency.
For example, 9-methoxy-6-(piperazin-1-yl)-11H-indeno[1,2-c]
quinolin-11-one O-3-(dimethylamino)propyloxime (5)31 and
Received: January 17, 2011
Published: May 20, 2011
r
2011 American Chemical Society
4446
dx.doi.org/10.1021/jm200046z J. Med. Chem. 2011, 54, 4446–4461
|

Journal of Medicinal Chemistry
ARTICLE
Chart 1. Structures of 1-[4-(Furo[2,3-b]quinolin-4-ylamino)
phenyl]ethanone (1), Its Oxime 2 and Methyloxime 3,
Camptothecin (4), Topotecan, Irinotecan, Combretastatin
A-4, Aminoalkyl Substituted Indenoquinolines 5 and 6, and
Targeted Compounds
Scheme 1a
a Reagents and conditions: (i) R1Cl, NaH, DMF; (ii) 3 N HCl, reflux;
(iii) R1ONH2 HCl, K2CO3, EtOH, reflux.
3
Scheme 2a
(E)-6-hydroxy-9-methoxy-11H-indeno[1,2-c]quinolin-11-one
O-2-(pyrrolidin-1-yl)ethyloxime (6)33 were found to be more
active than 4 against the growth of A549 with IC50 values of 0.38 and
0.89 μM, respectively. The present report describes the synthesis
and anticancer evaluation of 4-anilinofuro[2,3-b]quinoline derivatives
which bear various aminoalkyl side chains with an aim to improve
water solubility, selective cytotoxicity, and bioavailability of the lead
compound 1.Analoguesof1have also been synthesized and evaluated.
’ RESULTS AND DISCUSSION
Synthesis of 4-Anilinofuro[2,3-b]quinoline Derivatives.
The preparation of aminoalkyl substituted 4-anilinofuro[2,
3-b]quinoline derivatives is outlined in Scheme 1. The known
benzophenone oxime (7) was alkylated with aminoalkyl chlor-
ides to give benzophenone aminoalkyloximes (8aꢀh) which
were hydrolyzed with 3 N HCl to afford their respective
aminoalkoxyamines (9aꢀh).34 Reaction of 4-acetylanilinofuro-
[2,3-b]quinolines (1)11 with the respective aminoalkoxyamines
(9aꢀh) gave exclusively (E)-1-[4-(furo[2,3-b]quinolin-4-ylami-
no)phenyl]ethanone aminoalkyloximes (13aꢀh) in a good overall
yield. The configuration of the aminoalkyloxime moiety was
determined by the 13C NMR spectra. The carbon of CH3 which
is anti to the aminoalkyloxime moiety (Z-form) shifted upfield
from δ 30.6 ppm (carbonyl precursor) to δ 18.8 ppm, while that
of the syn isomer (E-form) further shifted from 30.6 to 11.5
ppm.35 The CH3 carbon peak appeared at δ 12.63 ppm for
compound 13a, indicating that the methyl group is syn to the
aminoalkyloxime moiety and the sole product of (E)-form
isomer was obtained. The stereospecific oximination to give
aReagents and conditions: (i) 4-aminobenzenesulfonamide, EtOH/
H2O, conc HCl; (ii) 4-substituted aniline, EtOH/H2O, conc HCl.
E-form product rather than the Z-isomer can be realized in which
the aminoalkoxy side chain proximate the methyl group is less
sterically hindered.36 Accordingly, the (E)-form configuration
was assigned for compounds 13b (CH3 carbon peak appeared at
δ 12.74), 13c (δ 12.54), 13d (δ 12.52), 13e (δ 12.87), 13f
(δ 12.65), 13g (δ 12.70), and 13h (δ 12.54). Compounds 14aꢀh,
15aꢀh, and 16aꢀh were obtained from their respective carbonyl
precursors 10, 11, and 1214 under the same reaction conditions.
Certain analogues of compound 1 have been synthesized as
depicted in Scheme 2. Treatment of 3,4-dichlorofuro[2,3-b]quinoline
(17)37 and 3,4-dichloro-7-methoxyfuro[2,3-b]quinoline (18)14
with 4-aminosufonamide afforded 4-(3-chlorofuro[2,3-b]quin-
olin-4-ylamino)benzenesulfonamide (19) and 4-(3-chloro-7-
methoxyfuro[2,3-b]quinolin-4-ylamino)benzenesulfonamide
4447
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
Table 1. Inhibition of in Vitro Cancer Cells by 4-Anilinofuro[2,3-b]quinoline Derivativesa
a In this protocol, each cell line was inoculated and preincubated on a microtiter plate. Each of the tested compounds was then added at concentrations of
20.0 and 4.0 μg/mL and the culture incubated for 48 h. End-point determinations were made with sulforhodamine B, a protein-binding dye. Results for
each test agent are reported as the percent of growth of the treated cells against that of the untreated control cells.
4448
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
Table 2. Antiproliferative Activity [IC50 (μM)]a and Water Solubility of Selected 4-Anilinofuro[2,3-b]quinoline Derivatives
ARTICLE
compd
NCI-H460 (SI)b
MCF7 (SI)
SF-268 (SI)
MRC-5
water solubility (μg/mL)
1
6
10
8
2
3
4
0.03 ( 0.003 (29.67)
0.63 ( 0.03 (68.02)
11.12 ( 0.61 (0.08)
9.34 ( 0.92 (4.59)
0.19 ( 0.006 (4.68)
6.26 ( 1.02 (6.84)
0.89 ( 0.90
13a
42.85 ( 1.05
63
1049
58
13a HCl
3
13c
14a
14c
15a
16a
DARc
7.08 ( 0.67 (6.07)
0.71 ( 0.02 (66.25)
16.21 ( 0.36 (2.90)
3.96 ( 0.14 (11.39)
3.86 ( 0.13 (12.30)
0.38 ( 0.04 (2.32)
11.52 ( 0.02 (3.73)
31.01 ( 0.03 (1.52)
9.46 ( 0.23 (4.98)
36.23 ( 0.05 (1.24)
36.93 ( 0.31 (1.28)
5.03 ( 0.05 (0.17)
7.53 ( 0.41 (5.71)
9.14 ( 0.72 (5.15)
32.53 ( 1.25 (1.46)
8.15 ( 0.44 (5.53)
7.48 ( 0.36 (6.34)
0.60 ( 0.02 (1.47)
42.98 ( 0.86
47.04 ( 1.21
47.09 ( 2.27
45.11 ( 0.31
47.46 ( 0.38
0.88 ( 0.11
25
36
16
17
a Values are the average of three separate determinations. b SI: selectivity index = (IC50 of MRC-5)/(IC50 of cancer cell line). c DAR, daunorubicin.
(20), respectively, in a fairly good yield. Under similar reaction
conditions, compound 17 was reacted with 4-aminobenzoic acid
and 4-aminobenzamide to give 4-(3-chlorofuro[2,3-b]quinolin-
4-ylamino)benzoic acid (21) and 4-(3-chlorofuro[2,3-b]qui-
nolin-4-ylamino)benzamide (22), respectively. 4-(3-Chloro-7-
methoxyfuro[2,3-b]quinolin-4-ylamino)benzamide (23) and its
derivatives 24ꢀ27 were synthesized by treating 18 with 4-ami-
nobenzamide and its derivatives, respectively, under the same
reaction conditions.
against the growth of both NCI-H460 and SF-268 at 4 μg/mL,
indicating the terminal primary amine conferred greater activity.
Compounds 13eꢀh being inactive against all the cell lines tested
at 4 μg/mL implied that the bulky cyclic five- or six-membered
ring at the terminal aminoalkyl side chain is unfavorable. The
same SARs were observed for 14aꢀh in which the primary amine
derivatives, 14a and 14c, are more active than their respective
tertiary amine counterparts, 14b and 14d, while the cyclic five or
six-membered ring derivatives, 14eꢀh, were inactive at 4 μg/mL.
Comparable cytotoxicities exhibited by 13aꢀh and their respec-
tive 3-chloro counterpart 14aꢀh indicated that a chloro group
substituted at C-3 position of tricyclic furo[2,3-b]quinoline ring
did not affect antiproliferative activities. Compounds 13c and
14c are more active than their respective C-7 methoxy counter-
parts 15c and 16c, indicating a methoxy substituent at C-7
position is unfavorable. Analogues of compound 1 and their
derivatives, 19ꢀ27, were found to be inactive against the growth
of all cell lines tested.
The IC50 values and water solubilities of selected compounds
13a, 13c, 14a, 14c, 15a, and 16a are summarized in Table 2. For
comparison, water solubilities of lead compounds 1ꢀ3 were also
determined with a UV/vis spectrophotometer at a wavelength
that varied between 315 and 420 nm.38 Results indicated that the
water solubility decreased in the order 13a (63 μg/mL) > 13c
(58 μg/mL) > 14c (36 μg/mL) > 14a (25 μg/mL) > 16a
(17 μg/mL), 15a (16 μg/mL) > 2 (10 μg/mL), 3 (8 μg/mL), 1
(6 μg/mL). Oximination improved water solubility by approxi-
mately 1.7-fold (1, 6 μg/mL vs 2, 10 μg/mL). Introduction of a
methyl group on the oxime moiety slightly decreased water
solubility (2, 10 μg/mL vs 3, 8 μg/mL). However, introduction
of an aminoethyl group on the oxime moiety enhanced water
solubility by more than 6-fold (2, 10 μg/mL vs 13a, 63 μg/mL).
The water solubility of 13a can be further enhanced by the
Antiproliferative Activities and Water Solubilities. The
newly synthesized 4-anilinofuro[2,3-b]quinoline 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 was inoculated and preincubated on a
microtiter plate. Test agents were then added at 20.0 and 4.0 μg/mL,
respectively, and the culture was incubated for 48 h. End-point
determinations were made with sulforhodamine B, a protein-
binding dye. Results for each test agent are reported as the
percent of growth of the treated cells against the untreated
control cells as shown in Table 1. The growth inhibitory activities
of compounds 1ꢀ3 are comparable and are approximately
equally potent to that of (E)-1-(4-(furo[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-aminoethyloxime (13a) against these
three cancer cell lines at 4 μg/mL. However, compounds 1ꢀ3
are much less active than 13a at 20 μg/mL, suggesting that these
three lead compounds could be poorly water-soluble. Compar-
able antiproliferative activities of compounds 1ꢀ3 at 4 and
20 μg/mL have also implied the limitation of their water solubility.
In the antiproliferative assay, compounds were dissolved com-
pletely in DMSO and then sequentially diluted with culture
medium to various concentrations. Compounds with poor water
solubility will gradually precipitate during the incubation which
made concentrations not reported correctly. The improved water
solubility of aminoalkyl substituted 4-anilinofuro[2,3-b]quin-
oline derivatives 13aꢀh, 14aꢀh, 15aꢀh, and 16aꢀh can be
realized in which a positive correlation was observed for anti-
proliferative potency and the concentration of tested compounds.
For example, 13a inhibited only 34% of MCF7 cell growth at
4 μg/mL while the growth of MCF7 was completely inhibited at
20 μg/mL. The antiproliferative activity of 13a, which bears an
aminoethyl side chain, was comparable to that of its homologous
aminopropyl counterpart 13c. Compounds 13a and 13c exhib-
ited morepotentinhibitoryactivitiesthan13b and 13d, respectively,
reaction with HCl to give its hydrochloride salt, 13a HCl (1049
3
μg/mL) which is approximately 17-fold more soluble than the
free base. Substitution of the lipophilic chloro atom or a methoxy
group on the tricyclic furoquinoline pharmacophore decreased water
solubility so that 15a and 16a were less water-soluble than 13a.
Compound 1 was nonselective and exhibited a GI50 of
0.025 μM in the NCI’s full panel of 60 human cancer cells.11
In contrast to compound 1, compounds 13aꢀ16a are selectively
active against the growth of NCI-H460 and the potency decreased
in the order of 13a (IC50 = 0.63 μM) > 14a (0.71 μM) > 16a
4449
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
Table 3. Pharmacokinetic Parameters of the Tested
Compounds (1, 13a HCl, and 14a) in fasted Male CD-1 (Crl)
3
Mice
PK Parameters
Cmax (ng/mL)c
1
13a HCl
14a
3
iva
3064
211
0.1
1488.4
362.6
2.5
3601
409.8
6.1
AUC(0ꢀinf) (ng h/mL)
3
MRT (h)
CL (mL/(min kg))
158
1.2
91.9
13.5
38.8
4.9f
81.3
30.0
103.8
14.7f
114.3
242.6
1.0
3
Vss (L/kg)
Vz (L/kg)
t1/2 (h)
4.1
0.3d
pob
Cmax (ng/mL)
21
1905.0
2071.6
0.5
AUC(0ꢀinf) (ng h/mL)
45
3
Tmax (h)
0.3
MRT (h)
2.7
2.0 e
3.0
3.4g
2.8
1.7h
t1/2 (h)
bioavailability (%)
2.1
57.1
5.9
a iv: single intravenous dosing at 2.0 mg/kg. b po: single oral dosing at
c
20 mg/kg. Cmax was determined from the extrapolated plasma con-
centration at time 0. d t1/2 was determined from 0.5 to 1.5 h time points.
f
e t1/2 was determined from 2 to 6 h time points. t1/2 was determined
from 9 to 27 h time points. g t1/2 was determined from 2 to 24 h time
points. h t1/2 was determined from 2 to 9 h time points.
Figure 1. Mean plasma concentrationꢀtime profiles of 13a HCl (A)
3
(3.86 μM) > 15a (3.96 μM) as shown in Table 2. With the
exception of MCF7, a side chain of 2-aminoethyl group is
more active than a 3-aminopropyl moiety as evidenced by the
fact that 13a is more active than 13c while 14a is more active
than 14c. Compounds 13a and 14a are selectively active
against the growth of NCI-H460 with IC50 of 0.63 and
0.71 μM, respectively, and are inactive against the growth of
human lung fibroblast cell line MRC-5, with IC50 of 42.85 and
47.04 μM, respectively. Although compounds 13a and 14a are
less active than 4 and daunorubicin (DAR) against NCI-H460,
the selectivity indexes (SI, (IC50 of MRC-5)/(IC50 of NCI-
H460)) for 13a and 14a are 68.02 and 66.25, respectively, which
are more favorable than for 4 (29.67) and DAR (2.32). There-
fore, both compounds 13a and 14a were selected as new leads for
further investigations.
and 14a (B) in male CD-1 (Crl) mice following single intravenous (iv, 2
mg/kg) and oral (po, 20 mg/kg) administration.
oral bioavailability (5.9%) and short plasma half-life (1.7 h)
following an oral dosing of 20 mg/kg.
Preferential Inhibitory Activity of 13a to Lung Cancer Cell
Lines. In order to examine whether compound 13a has prefer-
ential inhibitory activity to lung cancer cell lines, five lung cancer
cell lines including NCI-H460, A549, H1299, H661, and CL1ꢀ5;
eight non-lung-cancer cell lines including 786-O, AGS, PC3,
BT483, HeLa, SAS, SKHep, and CE81T; and two normal
fibroblast cell lines including MRC-5 and Hs68 were employed
for determing their IC50 values. Results in Table 4 showed that
lung cancer cell lines are the most susceptible with an IC50 of
6.58 μM or less in each case while renal cell carcinoma (RCC
786-O) is the most resistant with an IC50 of 24.0 μM. Among
these lung carcinomas, a specific cell type of non-small-cell lung
carcinomas, NCI-H460, H661, and H1229 are the most suscep-
tible with IC50 values of 0.63, 0.98, and 3.08 μM, respectively.
The selectivity index (SI, (IC50 of MRC-5)/(IC50 of cancer cell))
for NCI-H460, H661, and H1229 is 68.02, 43.72, and 13.91,
respectively.
Compound 13a Inhibits the Microtubule Formation,
Causes Mitotic Arrest and Mitotic Catastrophe, and Induces
Apoptosis. The observation of a numerous rounded-up H460
(Figure 2A) after 1 μM 13a treatment for 24 h indicated that
compound 13a may influence the cell cycle. To determine the
association between 13a-induced growth inhibition and cell cycle
deregulation, flow cytometry with PI staining was used to
examine the ploidy levels of 13a treated cells. The results in
Figure 2B showed that 13a induced H460 cell accumulation in
4N ploidy in a dose dependent manner after drug treatment for
24 h. These results suggested that 13a may cause H460 cell arrest
in the G2/M phase. In addition, the increase of the sub-G1 cell
population after the 3 μM 13a treatment for 24 h indicated that
Pharmacokinetic Evaluation. Pharmacokinetic properties of
the lead compound 1 and two of the newly synthesized 4-ani-
linofuro[2,3-b]quinoline derivatives 13a HCl and 14a were
3
evaluated for their pharmacokinetic properties, and results are
summarized in Table 3. Compound 1 exhibited low oral bioavail-
ability (2.1% only) and short plasma half-life (2.0 h) following an
oral dosing of 20 mg/kg. On the other hand, 13a HCl exhibited
3
a high oral bioavailability (57.1%) and a moderate plasma half-life
(3.4 h). Following an oral dosing of 20 mg/kg, 13a HCl showed
3
rapid oral absorption in mice, with a short Tmax of 0.5 h, while a
significant second absorption peak appeared at 1.5 h after dosing.
Interestingly, the third absorption peak was observed at 9 h
postdose as shown in Figure 1. These results indicate the multiple
absorption sites of 13a HCl in mouse after oral administration,
3
likely also including enterohepatic recirculation. The mean Cmax
and AUC of 13a HCl were 1905 ng/mL and 2072 ng h/mL,
3
3
respectively. The multiple absorption of 13a HCl is unique and
3
interesting because it usually occurs only in the sustain-released
drugs with special formulation. Although compounds 13a and
14a exhibited comparable antiproliferative potency and selec-
tivity, we decided not to further explore 14a because of its low
4450
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
Table 4. Antiproliferative Activities [IC50 (μM)]a of 13a
against the Growth of Certain Different Types of Cancer Cells
and the Human Lung Fibroblast Cell Lines
cell
type
IC50 (SI)b
H460
large cell lung carcinoma
0.63 ( 0.03 (68.02)
6.58 ( 2.99 (6.51)
3.08 ( 1.12 (13.91)
0.98 ( 0.27 (43.72)
5.18 (8.27)
A549
human lung adenocarcinoma
non-small-cell lung carcinoma
large cell lung carcinoma
H1299
H661
CL1ꢀ5
metastatic lung adenocarcinoma
RCC 786-O renal cell carcinoma
24.0 ( 2.0 (1.77)
13.77 ( 0.04 (3.09)
11.85 ( 0.49 (3.62)
10.16 ( 0.90 (4.22)
AGS
human stomach adenocarcinoma
PC-3
human prostate cancer
BT483
HeLa
SAS
human breast carcinomas
human cervical epithelioid carcinoma 8.31 ( 0.60 (5.16)
human oral squamous carcinoma
hepatocellular carcinoma
human esophageal carcinoma
human lung fibroblast
15.50 ( 2.60 (2.76)
13.13 ( 3.75 (3.26)
16.95 ( 1.88 (2.53)
42.85 ( 1.05
SKHep
CE81T
MRC-5
Hs68
foreskin, fibroblast
28.90 ( 2.48
a Values are the average of three separate determinations. b SI: selectivity
index = (IC50 of MRC-5)/(IC50 of cancer ell line).
Figure 2. Compound 13a caused mitotic arrest at G2/M, induced
apoptosis and mitotic catastrophe of NCI-H460. (A) H460 cells treated
with compound 13a showed round-up phenotype. (B) Accumulation at
G2/M phase accompanied by significant increase of Sub-G1 phase cell
population after treatment with compound 13a. Compound 13a at
3 μM can induce sub-G1 phase accumulation after 24 h of treatment.
(C) Compound 13a can induce caspase cleavage and activation. (D)
Compound 13a can cause mitotic catastrophe. Compound 13 treated
H460 cells were subjected to immunofluorescence analysis using tubulin
antibody and DAPI staining. Green color indicated the R-tubulin. (E)
Immunoblotting analysis showed the increase of two mitotic specific
immunoreactivities, MPM2 and cyclin B, after compound 13a treat-
ment. (F) Compound 13a can inhibit the tubulin polymerization
in vitro.
DNA fragmentation and apoptosis may be followed by G2/M
arrest caused by compound 13a. This hypothesis was sup-
ported by the results from Figure 2C showing that 13a can
induce the cleavage of both caspase 3 and PARP, two
apoptotic signaling molecules involoved in DNA fragmenta-
tion, in a dose dependent manner. Together, these results
indicated that compound 13a may cause mitotic cell death
through the activation of the metaphase checkpoint and an
apoptosis program (Figure 2AꢀC).
To ensure that the cells are ready to complete cell division, the
mitotic spindle checkpoint plays a crucial role in regulating
mitosis. Mitotic catastrophe was defined as centrosome over-
duplication, multipolar spindle formation, and unbalanced divi-
sion which seemed to occurr in the 13a treated H460 cells. In
order to clarify whether 13a induced mitotic catastrophe, im-
munofluorescence analysis using antibodies against R-tubulin
was performed to examine the effect of 13a at a low concentra-
tion of 3 μM on the microtubule organization. Normal micro-
tubule distribution in interphase and metaphase of control H460
cells is shown in Figure 2D (right panel). The microtubule
distribution of 13a treated H460 cells was less extended and
showed many aster-like structures (Figure 2D, right panel) when
compared to the control with two centrosomes in metaphase
(Figure 2D, left panel). Three to four representatives of the 13a-
treated H460 cells (12 h) coimmunostained by R-tubulin and
DAPI are shown in Figure 2D in a higher magnification (1000ꢁ).
These cells showed abnormal centrosome number 9 ( 2
(50 cells were counted) and revealed that the increased centro-
somes were localized at each pole of the multiple spindles, and
the cells not deriving from equal division appeared. In addition,
the immunoblotting analysis results (Figure 2E) showed the
increase of two mitotic specific immunoreactivities, MPM2 and
cyclin B, in a dose dependent manner upon compound 13a
treatment for 16 h. Together with the immunofluorescence data
in Figure 2D, these data clearly demonstrated that compound
13a treatment induced mitotic arrest but not G2 arrest of H460
cells (G2/M arrest in Figure 2B). Moreover, these data strongly
suggested that compound 13a may cause cancer cell apoptosis
through inducing mitotic arrest and mitotic catastrophe mechanism.
To investigate the underlying mechanism of how compound
13a may cause mitotic arrest and mitotic catastrophe, we
investigated the inhibitory effects of compound 13a on micro-
tubule-spindle formation using H460 cells. Turbidity (OD 340
nM) increase indicated the microbutule formation in the in vitro
light-scattering assay. Figure 2Fa showed that 5 μg of bovine
tubulin can trigger the spontaneous microtubule formation that
can be inhibited by preincubation with compound 13a. Com-
pound 13a at 1 μM can inhibit about 50% of the microtubule
formation (Figure 2Fb) whereas 3 μM can completely inhibit the
microtubule formation (Figure 2Fc). These data indicated that
the direct binding and inhibition of the microtubule formation
may at least play a part in the mechanism of mitotic arrest and
mitotic catastrophe induced by compound 13a.
Molecular Modeling Studies. A possible binding site of 13a,
which was obtained by docking simulation using Autodock 3.0,39
is proposed herein. A comparison of binding modes of 13a,
paclitaxel, colchicine, and vinblastine is shown in Figure 3A. The
binding site of vinblastine is located in the R2ꢀβ1 interface,
encompassed by T7, H10, and S9 in the R2 subunit and by H6,
T5, and H6ꢀH7 in the β1 subunit,40 while that of colchicine is
encompassed by S8, S9, T7, H7, and H8 within β subunits, a
4451
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
Figure 3. (A) An overview of binding sites of 13a (in green), paclitaxel
(in blue), vinblastine (in pink), and colchicine (in gold) in R-tubuline
(in gray) and β-tubuline (in light blue) whose Asp199 side chain is
specified in red because it contributes the major interaction with the
studied compound. (B) Detailed interaction between β-tubulin (whose
backbone is in light blue) and 13a (in green).
region near the Rꢀβ interface within a dimer.41 Both vinblastine
and colchicine can prevent microtubual formation and destabi-
lize polymerization of microtubules.42 Paclitaxel is bound in the β
subunit, and the interaction with M-loop, a connection between
S7 and H9, is believed to enhance the polymerization of
microtubules.42 As indicated in Figure 3A, 13a is bound in a site
boxed by H5, H6, H7, H8, S5, and S7 within the β subunit and
detailed interaction is illustrated in Figure 3B. The carbonyl of
Figure 4. Effects of compound 13a HCl against human large cell
ꢀ
3
the COOH group of Asp199 is located 1.955 Å from the
carcinoma cell line NCI-H460 growth in the xenograft nude mice
model: (A) intraperitoneal administration (ip); (B) oral administration
(OR); (C) KaplanꢀMeier survival analysis.
hydrogen of the 4-NH group of 13a, whereas the center of mass
ꢀ
of the Phe262 benzene ring is located 5.042 Å from the hydrogen
of the terminal NH2 group inducing the formation of the
benzeneꢀamine complex.43 On the other hand, Ile165, Leu194,
and Val195 form a hydrophobic cleft to accommodate the
furo[2,3-b]quinoline moiety of 13a, whereas Ala256, Val257,
and Val260 provide hydrophobic interaction to the para-sub-
stituted 4-aniline moiety.
Xenographic Studies of Lung Cancer Model. Compound
13a HCl was evaluated against tumor growth in vivo in a nude
3
mouse xenograft model. In this approach, we first injected 1 ꢁ
106 NCI-H460 cells into mice subcutaneously. Until tumorigen-
Topoisomerases Assay. The topoisomerases inhibitory ac-
sis (tumor size reached to 5 mm3), administration of 13a HCl in
3
tivities of compounds 13a HCl, 13c, 14a, 14c, 15a, and 16a were
the peritumoral region lasted for 6 days. Compound 13a HCl
3
3
investigated in vitro. The supercoiled plasmid DNA relaxation
experiments were performed according to the protocol described
previously.33 Results indicated no significant topoisomerases I
and II inhibitory activities can be detected in all compounds
examined, even at 30 μM.
was dissolved in vehicle, DMSO/Tween 80/PBS (1:1:8). The
final administration doses were 10 and 20 mg/kg, respectively for
ip injection, while the doses were 60 and 120 mg/kg, respectively,
for oral administration. A total of 14 nude mice have been tested
(4 for control, 4 for 10 mg/kg concentrations, and 6 for 20 mg/kg
4452
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
Figure 5. Effects of compound 13a HCl against human lung adenocarcinoma H1299 growth in orthotopic murine model.
3
concentrations). As shown in Figure 4A (ip) and Figure 4B
be absorbed readily through oral administration and distributed
to lung tissue and exhibited significant efficacy in inhibiting the
growth of lung cancers. These results indicated that 13a is a
potential anticancer drug candidate selectively active against the
growth of non-small-cell lung cancers.
(oral), the tumor size of 13a HCl treated nude mice were
3
significantly lower than that of the control. In terms of tumor
growth curve, there is a significant difference between treatment
of 10 and 20 mg/kg at later period. Although the sample size is
only 14, the preliminary results showed the excellent tumor
regression and long-term survival of 13a HCl-treated mice in the
3
’ EXPERIMENTAL SECTION
xenograft model. The survival rate has been improved for 13a
3
HCl treated nude mice as shown in Figure 4C. Therefore,
compound 13a is a potential anticancer drug candidate that is
effective both in vitro and in vivo.
General. Melting points were determined on a Electrothermal
IA9100 melting point apparatus and are uncorrected. UV spectra
(λmax in nm) were recorded in spectroscopic grade MeOH on a
Shimadzu UV-160A UVꢀvis spectrophptometer. Nuclear magnetic
resonance (1H and 13C) spectra were recorded on a Varian-Unity-400
spectrometer. Chemical shifts were expressed in parts per million (δ)
with tetramethylsilane (TMS) as an internal standard. NMR data are
given as multiplicity (s = singlet; d = doublet; dd = double doublet; t =
triplet; and m = multiplet), numbers of protons, coupling constants (J),
and types of protons (Pyr = pyrrolidinyl; Pip = piperidinyl; Mor =
morphorlinyl). Thin-layer chromatography was performed on silica gel
60 F-254 plates purchased from E. Merck and Co. High-resolution mass
spectroscopic (HRMS) data were provided by the Joint Center for High
Valued Instruments at National Sun Yat-sen University using Bruker
APEX II (ESI) mass spectrometer. The elemental analyses were
performed in the Instrument Center of National Science Council at
National Cheng-Kung University and National Chung-Hsing University
using a Heraeus CHN-O Rapid EA instrument. Purity of tested
compounds was greater than 95%.
Orthotopic Murine Model of Lung Cancers (H-1229).
Compound 13a HCl was further investigated in orthotopic lung
3
cancer model in nude mice using H-1229 cells. Results reported
in Figure 5 indicated that 13a HCl can be absorbed readily
3
through oral administration, distributed to lung tissue, and
exhibited significant efficacy in inhibiting the growth of lung
cancers.
’ CONCLUSION
We have synthesized certain aminoalkyl side chain bearing
4-anilinofuro[2,3-b]quinoline derivatives for anticancer evalua-
tion. Results indicated that the introduction of an aminoalkyl side
chain on the 4-anilinofuro[2,3-b]quinoline pharmacophore im-
proved not only water solubility but also selective cytotoxicity.
Among them, (E)-1-(4-(furo[2,3-b]quinolin-4-ylamino)phenyl)
ethanone O-2-aminoethyloxime (13a) is selectively active
against the growth of non-small-cell lung carcinoma such as NCI-
H460 and NCI-H661. Xenographic studies indicated that the
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-2-Aminoethyloxime (13a). A mixture of 1-[4-(furo[2,3-b]quin-
olin-4-ylamino)phenyl]ethanone11 (1, 0.30 g, 1 mmol), 2-aminoet-
hoxyamine HCl34 (0.28 g, 2.5 mmol), and K2CO3 (0.69 g, 5.0 mmol)
tumor size of the 13a HCl treated nude mice was significantly
3
3
lower than that of the control. Orthotopic lung cancer model in
in EtOH (10 mL) was refluxed for 4 h (TLC monitoring). The mixture
was evaporated under reduced pressure to give a residue which was
nude mice using H1229 cells further indicated that 13a HCl can
3
4453
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
dissolved in CH2Cl2 (50 mL). The CH2Cl2 layer was washed with H2O,
brine, dried (Na2SO4), and evaporated. Purification of residue with flash
column chromatography (FC, silica gel, MeOH/CH2Cl2 = 1/50) and
then crystallization from EtOH gave 13a (0.45 g, 96%). Mp:
112ꢀ113 °C. IR (KBr): 3216, 1578, 1517. UV (MeOH): 372 (4.22),
260 (4.52), 208 (4.53). 1H NMR (400 MHz, DMSO-d6): 2.29 (s, 3H,
CH3), 3.17 (m, 2H, OCH2CH2N), 4.35 (t, 2H, J = 5.0 Hz,
OCH2CH2N), 5.94 (d, 1H, J = 2.8 Hz, 3-H), 7.33ꢀ7.35 (m, 2H, ArH),
7.57ꢀ7.61 (m, 1H, 6-H), 7.78ꢀ7.88 (m, 4H, 2-, 7-H, ArH), 8.00 (d, 1H,
J = 8 0.0 Hz, 5-H), 8.23 (br s, 2H, NH2), 8.60 (d, 1H, J = 8.4 Hz, 8-H),
10.37 (br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6): 12.63, 38.27,
69.78, 103.86, 106.07, 117.21, 122.75 (2C), 123.76, 123.95, 125.02,
127.01 (2C), 130.81, 131.82, 141.60, 141.98, 143.07, 144.76, 155.14,
160.44. Anal. Calcd for C21H20N4O2 0.6H2O 0.5HCl: C, 64.77; H,
129.14, 129.19, 132.07, 140.40, 141.75, 142.77, 145.97, 153.92, 163.27.
Anal. Calcd for C24H26N4O2 0.5H2O: C, 67.43; H, 6.39; N, 13.11.
3
Found: C, 67.35; H, 6.69; N, 12.94. HRMS (ESI) calcd for C24H27N4O2
[M þ H]þ 403.2134, found 403.2136.
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-2-(Pyrrolidin-1-yl)ethyloxime (13e). 13e was obtained from 1
and 2-pyrrolidin-1-ylethoxyamine HCl as described for 13a: 61% yield
3
as a brown liquid. IR (KBr): 3217, 1577, 1519. UV (MeOH): 372 (4.22),
260 (4.56), 208 (4.51). 1H NMR (400 MHz, CDCl3): 2.06ꢀ2.10
(m, 4H, Pyr-H), 2.26 (s, 3H, CH3), 3.24 (br s, 4H, Pyr-H), 3.35
(t, 2H, J = 4.8 Hz, OCH2CH2N), 4.60ꢀ4.63 (m, 2H, OCH2CH2N),
6.23 (d, 1H, J = 2.8 Hz, 3-H), 7.15ꢀ7.18 (m, 2H, ArH), 7.29 (br s, 1H,
NH), 7.46ꢀ7.51 (m, 2H, 2-H, 6-H), 7.63ꢀ7.66 (m, 2H, ArH),
7.69ꢀ7.73 (m, 1H, 7-H), 8.07ꢀ8.14 (m, 2H, 8-H, 5-H). 13C NMR
(100 MHz, CDCl3): 12.87, 23.27 (2C), 53.80, 54.27 (2C), 69.56,
105.71, 106.51, 118.65, 120.44 (2C), 121.11, 123.86, 127.10 (2C),
129.10, 129.24, 130.76, 140.15, 142.48, 142.92, 146.00, 155.58, 163.22.
Anal. Calcd for C25H26N4O2 1.0H2O 1.0HCl: C, 64.03; H, 6.23; N,
3
3
5.62; N, 14.39. Found: C, 64.88; H, 5.97; N, 14.17. HRMS (ESI) calcd
for C21H21N4O2 [M þ H]þ 361.1664, found 361.1663.
A mixture of 13a (0.38 g) and 6 N HCl (2 mL) in EtOH (20 mL) was
stirred for 2 h at room temperature. The precipitate was collected and
crystallized from EtOH to give 13a HCl. Anal. Calcd for C21H20N4O2
3
3
11.95. Found: C, 64.19; H, 6.44; N, 11.87. HRMS (ESI) calcd for
3
3
C25H27N4O2 [M þ H]þ 415.2134, found 415.2135.
0.6H2O 1.8HCl: C, 57.74; H, 5.31; N, 12.83. Found: C, 58.07; H, 5.71;
N, 12.43.
3
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-2-(Piperidin-1-yl)ethyloxime (13f). 13f was obtained from 1
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-2-(Dimethylamino)ethyloxime (13b). 13b was obtained from
and 2-piperidin-1-ylethoxyamine HCl as described for 13a: 85% yield as
3
1 and 2-dimethylaminoethoxyamine HCl as described for 13a: 90%
a brown liquid. IR (KBr): 3221, 1579, 1519. UV (MeOH): 368 (4.15),
260 (4.51), 206 (4.51). 1H NMR (400 MHz, CDCl3): 1.44ꢀ1.48 (m,
2H, Pip-H), 1.57ꢀ1.65 (m, 4H, Pip-H), 2.25 (s, 3H, CH3), 2.53ꢀ2.78
(m, 4H, Pip-H), 3.81 (t, 2H, J = 5.6 Hz, OCH2CH2N), 4.37 (t, 2H, J =
6.0 Hz, OCH2CH2N), 6.18 (d, 1H, J = 2.4 Hz, 3-H), 7.02 (br s, 1H,
NH), 7.14ꢀ7.17 (m, 2H, ArH), 7.46ꢀ7.50 (m, 2H, 2-H, 6-H),
7.66ꢀ7.73 (m, 3H, 7-H, ArH), 8.05ꢀ8.10 (m, 2H, 8-H, 5-H). 13C
NMR (100 MHz, CDCl3): 12.65, 24.13, 25.79, 25.87, 54.89, 54.93,
57.85, 72.18, 105.72, 106.06, 118.34, 120.72, 120.94 (2C), 123.78,
127.04 (2C), 129.17 (2C), 132.11, 140.38, 141.71, 142.77, 145.99,
153.83, 163.28. HRMS (ESI) calcd for C26H29N4O2 [M þ H]þ
429.2290, found 429.2292.
3
yield as a deep brown liquid. IR (KBr): 3221, 1578, 1519. UV (MeOH):
372 (4.18), 260 (4.48), 208 (4.50). 1H NMR (400 MHz, CDCl3): 2.27
(s, 3H, CH3), 2.37 (s, 6H, N(CH3)2), 2.74 (t, 2H, J = 5.8 Hz,
OCH2CH2N), 4.35 (t, 2H, J = 5.8 Hz, OCH2CH2N), 6.19 (d, 1H, J =
2.8 Hz, 3-H), 6.90 (br s, 1H, NH), 7.15ꢀ7.17 (m, 2H, ArH), 7.47ꢀ7.52
(m, 2H, 2-H, 6-H), 7.67ꢀ7.74 (m, 3H, 7-H, ArH), 8.04 (dd, 1H, J = 8.8,
1.2 Hz, 5-H), 8.09 (dd, 1H, J = 8.8, 2.4 Hz, 8-H). 13C NMR (100 MHz,
CDCl3): 12.74, 45.91 (2C), 58.20, 72.29, 105.73, 106.09, 118.31,
120.61, 120.92 (2C), 123.86, 127.10 (2C), 129.21, 129.23, 132.12,
140.27, 141.68, 142.84, 145.99, 154.00, 163.28. Anal. Calcd for
C23H24N4O2 2.0H2O 1.1HCl: C, 59.46; H, 6.31; N, 12.06. Found:
3
3
C, 59.68; H, 6.40; N, 11.77. HRMS (ESI) calcd for C23H25N4O2
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-2-Morpholinoethyloxime (13g). 13g was obtained from 1 and
[M þ H]þ 389.1977, found 389.1979.
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-3-Aminopropyloxime (13c). 13c was obtained from 1 and
2-morpholinoethoxyamine HCl as described for 13a: 73% yield. Mp
3
92ꢀ93 °C. IR (KBr): 3269, 1578, 1518. UV (MeOH): 372 (4.33), 260
1
3-aminopropoxyamine HCl as described for 13a: 96% yield. Mp:
(4.67), 208 (4.62). H NMR (400 MHz, CDCl3): 2.25 (s, 3H, CH3),
3
83ꢀ85 °C. IR (KBr): 3237, 1578, 1517. UV (MeOH): 366 (4.20),
258 (4.48), 210 (4.50). 1H NMR (400 MHz, CDCl3): 1.90 (quin, 2H,
J = 6.4 Hz, OCH2CH2CH2N), 2.25 (s, 3H, CH3), 2.88 (t, 2H, J = 6.8 Hz,
OCH2CH2CH2N), 4.30 (t, 2H, J = 6.0 Hz, OCH2CH2CH2N), 6.17
(d, 1H, J = 2.8 Hz, 3-H), 7.03 (br s, 1H, NH), 7.14ꢀ7.17 (m, 2H, ArH),
7.46ꢀ7.50 (m, 2H, 2-H, 6-H), 7.66ꢀ7.73 (m, 3H, 7-H, ArH),
8.04ꢀ8.10 (m, 2H, 5-H, 8-H). 13C NMR (100 MHz, CDCl3): 12.54,
33.25, 39.34, 72.01, 105.74, 106.01, 118.31, 120.69, 120.98 (2C), 123.79,
127.01 (2C), 129.16, 129.18, 132.14, 140.39, 141.67, 142.76, 145.97,
2.58ꢀ2.60 (m, 4H, Mor-H), 2.78 (t, 2H, J = 5.6 Hz, OCH2CH2N),
3.73ꢀ3.76 (m, 4H, Mor-H), 4.37 (t, 2H, J = 5.6 Hz, OCH2CH2N), 6.18
(d, 1H, J = 2.8 Hz, 3-H), 6.97 (br s, 1H, NH), 7.14ꢀ7.17 (m, 2H, ArH),
7.46ꢀ7.50 (m, 2H, 2-H, 6-H), 7.66ꢀ7.73 (m, 3H, 7-H, ArH),
8.04ꢀ8.10 (m, 2H, 8-H, 5-H). 13C NMR (100 MHz, CDCl3): 12.70,
54.05 (2C), 57.61, 60.95 (2C), 72.03, 105.70, 106.13, 118.36, 120.66,
120.88 (2C), 123.84, 127.06 (2C), 129.19 (2C), 131.97, 140.28, 141.78,
142.83, 145.98, 154.02, 163.26. Anal. Calcd for C25H26N4O3 0.5H2O:
3
C, 68.32; H, 6.19; N, 12.75. Found: C, 68.20; H, 6.21; N, 12.78. HRMS
(ESI) calcd for C25H27N4O3 [M þ H]þ 431.2083, found 431.2080.
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-4-Morpholinobutyloxime (13h). 13h was obtained from 1 and
153.72, 163.27. Anal. Calcd for C22H22N4O2 0.9H2O: C, 67.64; H,
3
6.14; N, 14.34. Found: C, 67.97; H, 6.32; N, 14.02. HRMS (ESI) calcd
for C22H23N4O2 [M þ H]þ 375.1821, found 375.1823.
(E)-1-(4-(Furo[2,3-b]quinolin-4-ylamino)phenyl)ethanone
O-3-(Dimethylamino)propyloxime (13d). 13d was obtained
4-morpholinobutoxyamine HCl as described for 13a: 73% yield. Mp:
3
87ꢀ88 °C. IR (KBr): 3263, 1579, 1518. UV (MeOH): 368 (4.23), 260
(4.60), 208 (4.57). 1H NMR (400 MHz, CDCl3): 1.62ꢀ1.79 (m, 4H,
OCH2(CH2)2CH2N), 2.25 (s, 3H, CH3), 2.38ꢀ2.46 (m, 6H, OCH2-
(CH2)2CH2N, Mor-H), 3.72ꢀ3.74 (m, 4H, Mor-H), 4.23 (t, 2H, J = 5.6
Hz, OCH2(CH2)2CH2N), 6.16 (d, 1H, J = 2.8 Hz, 3-H), 7.06 (br s, 1H,
NH), 7.14ꢀ7.16 (m, 2H, ArH), 7.45ꢀ7.46 (m, 2H, 2-H, 6-H),
7.66ꢀ7.70 (m, 3H, 7-H, ArH), 8.04ꢀ8.09 (m, 2H, 8-H, 5-H). 13C
NMR (100 MHz, CDCl3): 12.54, 23.07, 27.18, 53.68 (2C), 58.82, 66.93
(2C), 73.94, 105.72, 105.99, 118.30, 120.69, 121.00 (2C), 123.78,
126.99 (2C), 129.14, 129.18, 132.23, 140.42, 141.64, 142.74, 145.96,
from 1 and 3-dimethylaminopropoxyamine HCl as described for 13a:
3
75% yield. Mp: 83ꢀ85 °C. IR (KBr): 3219, 1578, 1519. UV (MeOH):
1
368 (4.26), 258 (4.53), 210 (4.53). H NMR (400 MHz, CDCl3):
1.99ꢀ2.06 (m, 2H, OCH2CH2CH2N), 2.25 (s, 3H, CH3), 2.39 (s, 6H,
N(CH3)2), 2.59 (t, 2H, J = 7.6 Hz, OCH2CH2CH2N), 4.26 (t, 2H, J =
6.2 Hz, OCH2CH2CH2N), 6.19 (d, 1H, J = 2.8 Hz, 3-H), 6.93 (br s, 1H,
NH), 7.14ꢀ7.17 (m, 2H, ArH), 7.47ꢀ7.52 (m, 2H, 2-H, 6-H),
7.67ꢀ7.74 (m, 3H, 7-H, ArH), 8.04ꢀ8.10 (m, 2H, 8-H, 5-H). 13C
NMR (100 MHz, CDCl3): 12.52, 26.93, 44.93 (2C), 56.34, 71.99,
105.74, 106.07, 118.34, 120.75, 120.96 (2C), 123.81, 127.03 (2C),
153.60, 163.27. Anal. Calcd for C27H30N4O3 0.8H2O: C, 68.56; H,
3
4454
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
6.73; N, 11.84. Found: C, 68.47; H, 6.94; N, 11.81. HRMS (ESI) calcd
for C27H31N4O3 459.2396, found [M þ Hþ] 459.2399.
C, 64.41; H, 6.03; N, 12.77. HRMS (ESI) calcd for C24H26ClN4O2
[M þ H]þ 437.1744, found 437.1747.
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-2-(Pyrrolidin-1-yl)ethyloxime (14e). 14e was ob-
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-2-Aminoethyloxime (14a). 14a was obtained from
1-[4-(3-chlorofuro[2,3-b]quinolin-4-ylamino)phenyl]ethanone (10)14
tained from 10 and 2-pyrrolidin-1-ylethoxyamine HCl as described for
3
13a: 92% yield. Mp: 208ꢀ210 °C. IR (KBr): 3241, 1578, 1513. UV
and 2-aminoethoxyamine HCl as described for 13a: 95% yield. Mp:
3
1
(MeOH): 382 (4.15), 286 (4.31), 264 (4.37), 236 (4.58). H NMR
169ꢀ172 °C. IR (KBr): 3146, 1580, 1514. UV (MeOH): 382 (4.09),
264 (4.32), 236 (4.53), 208 (4.52). 1H NMR (400 MHz, CDCl3): 2.22
(s, 3H, CH3), 3.04 (t, 2H, J = 5.2 Hz, OCH2CH2N), 4.22 (t. 2H, J = 5.2
Hz, OCH2CH2N), 6.86ꢀ6.89 (m, 2H, ArH), 7.18 (br s, 1H, NH),
7.29ꢀ7.34 (m, 1H, 6-H), 7.53ꢀ7.56 (m, 2H, ArH), 7.66ꢀ7.70 (m, 2H,
2-H, 7-H), 7.81 (dd, 1H, J = 8.8, 0.8 Hz, 5-H), 8.06 (d, J = 8.8 Hz, 8-H).
13C NMR (100 MHz, CDCl3): 12.56, 41.55, 75.66, 107.99, 110.11,
118.09 (2C), 120.05, 123.99, 124.41, 127.11 (2C), 129.09, 129.89,
130.68, 140.65, 141.53, 144.62, 146.77, 154.44, 160.73. Anal. Calcd for
(400 MHz, CDCl3): 2.12 (br s, 4H, Pyr-H), 2.22 (s, 3H, CH3),
3.32ꢀ3.40 (m, 6H, Pyr-H, OCH2CH2N), 4.62ꢀ4.65 (m, 2H,
OCH2CH2N), 6.87ꢀ6.90 (m, 2H, ArH), 7.19 (br s, 1H, NH),
7.33ꢀ7.37 (m, 1H, 6-H), 7.53ꢀ7.56 (m, 2H, ArH), 7.68ꢀ7.73 (m,
2H, 2-H, 7-H), 7.84ꢀ7.87 (m, 1H, 5-H), 8.08ꢀ8.10 (m, 1H, 8-H). 13C
NMR (100 MHz, CDCl3): 12.86, 23.26 (2C), 53.66, 54.20 (2C), 69.26,
108.36, 110.10, 117.80 (2C), 120.27, 124.12, 124.28, 127.20 (2C),
129.16, 129.68, 129.94, 140.85, 141.21, 145.15, 146.75, 155.76, 160.72.
Anal. Calcd for C25H25ClN4O2 0.2H2O 1.0H2O: C, 61.40; H, 5.44;
C21H19ClN4O2 0.4H2O: C, 62.74; H, 4.96; N, 13.94. Found: C, 62.40;
3
3
3
H, 5.17; N, 13.76. HRMS (ESI) calcd for C21H20ClN4O2 [M þ H]þ
N, 11.46. Found: C, 61.61; H, 5.64; N, 11.16. HRMS (ESI) calcd for
C25H26ClN4O2 [M þ H]þ 449.1744, found 449.1746.
395.1275, found 395.1274.
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-2-(Dimethylamino)ethyloxime (14b). 14b was
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-2-(Piperidin-1-yl)ethyloxime (14f). 14f was ob-
obtained from 10 and 2-dimethylaminoethoxyamine HCl as described
tained from 10 and 2-piperidin-1-ylethoxyamine HCl as described for
3
3
for 13a: 97% yield. Mp: 118ꢀ122 °C. IR (KBr): 3398, 1578, 1520. UV
13a: 69% yield. Mp: 136ꢀ138 °C. IR (KBr): 3386, 1578, 1516. UV
1
1
(MeOH): 382 (4.17), 266 (4.49), 236 (4.62), 206 (4.66). H NMR
(MeOH): 382 (4.12), 264 (4.33), 234 (4.50), 210 (4.48). H NMR
(400 MHz, CDCl3): 1.41ꢀ1.65 (m, 6H, Pip-H), 2.20 (s, 3H, CH3),
2.52 (br s, 4H, Pip-H), 2.75 (t, 2H, J = 6.0 Hz, OCH2CH2N), 4.23
(t, 2H, J = 6.2 Hz, OCH2CH2N), 6.86ꢀ6.90 (m, 2H, ArH), 7.18 (br s,
1H, NH), 7.30ꢀ7.35 (m, 1H, 6-H), 7.54ꢀ7.57 (m, 2H, ArꢀH),
7.67ꢀ7.57 (m, 2H, 2-H, 7-H), 7.82ꢀ7.86 (m, 1H, 5-H), 8.06ꢀ8.09
(m, 1H, 8-H). 13C NMR (100 MHz, CDCl3): 12.65, 24.08, 25.80 (2C),
54.88 (2C), 57.78, 72.01, 107.91, 110.10, 118.13 (2C), 120.00, 123.95,
124.44, 127.08 (2C), 129.08, 129.87, 130.86, 140.61, 141.59, 144.49,
146.77, 153.96, 160.73. Anal. Calcd for C26H27ClN4O2 1.1H2O 1.0
HCl: C, 60.14; H, 5.86; N, 10.79. Found: C, 59.92; H, 6.12; N, 10.47.
HRMS (ESI) calcd for C26H28ClN4O2 [M þ H]þ 463.1901, found
463.1904.
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-2-Morpholinoethyloxime (14g). 14g was obtained
(400 MHz, CDCl3): 2.22 (s, 3H, CH3), 2.51 (s, 6H, N(CH3)2), 2.94
(t, 2H, J = 5.4 Hz, OCH2CH2N), 4.42 (t, 2H, J = 5.4 Hz, OCH2CH2N),
6.86ꢀ6.90 (m, 2H, ArH), 7.19 (br s, 1H, NH), 7.32ꢀ7.36 (m, 1H,
6-H), 7.53ꢀ7.56 (m, 2H, ArH), 7.67ꢀ7.71 (m, 2H, 2-H, 7-H),
7.83ꢀ7.86 (m, 1H, 5-H), 8.07ꢀ8.09 (m, 1H, 8-H). 13C NMR (100
MHz, CDCl3): 12.78, 45.10 (2C), 57.48, 70.87, 110.10, 117.10, 118.01
(2C), 120.09, 124.02, 124.39, 127.14 (2C), 129.10, 129.91, 130.38,
140.70, 141.44, 144.75, 146.75, 154.77, 160.72. Anal. Calcd for
C23H23ClN4O2 1.5H2O: C, 61.40; H, 5.83; N, 12.45. Found: C,
3
3
3
61.17; H, 5.98; N, 12.09. HRMS (ESI) calcd for C23H24ClN4O2 [M
þ H]þ 423.1588, found 423.1587.
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-3-Aminopropyloxime (14c). 14c was obtained
from 10 and 3-aminopropoxyamine HCl as described for 13a: 98%
3
from 10 and 2-morpholinoethoxyamine HCl as described for 13a: 96%
yield. Mp: 114ꢀ116 °C. IR (KBr): 3143, 1579, 1512. UV (MeOH): 382
(4.11), 264 (4.32), 234 (4.50), 210 (4.49). 1H NMR (400 MHz,
CDCl3): 1.92 (quin, 2H, J = 6.4 Hz, OCH2CH2CH2N), 2.19 (s, 3H,
CH3), 2.90 (t, 2H, J = 6.8 Hz, OCH2CH2CH2N), 4.26 (t, 2H, J = 6.0
Hz, OCH2CH2CH2N), 6.87ꢀ6.90 (m, 2H, ArH), 7.19 (br s, 1H, NH),
7.30ꢀ7.34 (m, 1H, 6-H), 7.53ꢀ7.56 (m, 2H, ArH), 7.66ꢀ7.70 (m, 2H,
2-H, 7-H), 7.82 (dd, 1H, J = 8.4, 1.0 Hz, 5-H), 8.06 (d, 1H, J = 8.4 Hz,
8-H). 13C NMR (100 MHz, CDCl3): 12.55, 32.43, 39.09, 71.75, 107.94,
110.13, 118.16 (2C), 120.04, 123.98, 124.43, 127.09 (2C), 129.08,
129.90, 130.83, 140.63, 141.61, 144.56, 146.78, 154.02, 160.75.
HRMS (ESI) calcd for C22H22ClN4O2 [M þ H]þ 409.1431, found
409.1430.
3
yield. Mp: 121ꢀ122 °C. IR (KBr): 3391, 1579, 1514. UV (MeOH): 382
(4.11), 264 (4.34), 234 (4.50), 210 (4.49). 1H NMR (400 MHz,
CDCl3): 2.19 (s, 3H, CH3), 2.54ꢀ2.57 (m, 4H, Mor-H), 2.75 (t, 2H,
J = 5.6 Hz, OCH2CH2N), 3.72ꢀ3.74 (m, 4H, Mor-H), 4.33 (t, 2H, J =
5.6 Hz, OCH2CH2N), 6.86ꢀ6.89 (m, 2H, ArH), 7.18 (br s, 1H, NH),
7.28ꢀ7.33 (m, 1H, 6-H), 7.52ꢀ7.56 (m, 2H, ArH), 7.67ꢀ7.70 (m, 2H,
2-H, 7-H), 7.81 (dd, 1H, J = 8.8, 0.8 Hz, 5-H), 8.06 (dd, 1H, J = 8.6, 0.6
Hz, 8-H). 13C NMR (100 MHz, CDCl3): 12.63, 53.98 (2C), 57.54,
66.90 (2C), 71.87, 107.97, 110.06, 117.97 (2C), 120.03, 123.91, 124.33,
127.03 (2C), 129.00, 129.82, 130.60, 140.60, 141.44, 144.56, 146.67,
154.03, 160.66. Anal. Calcd for C25H25ClN4O3 1.0H2O 0.5HCl: C,
3
3
59.91; H, 5.53; N, 11.18. Found: C, 60.05; H, 5.68; N, 10.88. HRMS
(ESI) calcd for C25H26ClN4O3 [M þ H]þ 465.1693, found 465.1695.
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-4-Morpholinobutyloxime (14h). 14h was obtained
(E)-1-(4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)phenyl)-
ethanone O-3-(Dimethylamino)propyloxime (14d). 14d was
obtained from 10 and 3-dimethylaminopropoxyamine HCl as de-
3
scribed for 13a: 96% yield. Mp: 104ꢀ106 °C. IR (KBr): 3147, 1578,
1520. UV (MeOH): 382 (4.17), 266 (4.45), 236 (4.62), 208 (4.59). 1H
NMR (400 MHz, CDCl3): 1.87ꢀ1.94 (m, 2H, OCH2CH2CH2N), 2.20
(s, 3H, CH3), 2.26 (s, 6H, N(CH3)2), 2.39ꢀ2.42 (m, 2H,
OCH2CH2CH2N), 4.21 (t, 2H, J = 6.4 Hz, OCH2CH2CH2N),
6.87ꢀ6.90 (m, 2H, ArH), 7.18 (br s, 1H, NH), 7.30ꢀ7.34 (m, 1H,
6-H), 7.54ꢀ7.57 (m, 2H, ArH), 7.66ꢀ7.70 (m, 2H, 2-H, 7-H), 7.82
(dd, 1H, J = 8.6, 1.0 Hz, 5-H), 8.06 (d, 1H, J = 8.4 Hz, 8-H). 13C NMR
(100 MHz, CDCl3): 12.49, 27.52, 45.44 (2C), 56.52, 72.29, 107.86,
110.11, 118.18 (2C), 119.99, 123.94, 124.46, 127.06 (2C), 129.08,
129.87, 131.04, 140.58, 141.65, 144.43, 146.80, 153.75, 160.74. Anal.
from 10 and 4-morpholinobutoxyamine HCl as described for 13a: 86%
3
yield. Mp: 112ꢀ113 °C. IR (KBr): 3138, 1614, 1580, 1512. UV
1
(MeOH): 382 (4.14), 266 (4.45), 236 (4.58), 206 (4.56). H NMR
(400 MHz, CDCl3): 1.60ꢀ1.77 (m, 4H, OCH2(CH2)2CH2N), 2.20
(s, 3H, CH3), 2.40 (t, 2H, J = 7.6 Hz, OCH2(CH2)2CH2N), 2.46 (br s,
4H, Mor-H), 3.72ꢀ3.74 (m, 4H, Mor-H), 4.19 (t, 2H, J = 6.4 Hz,
OCH2(CH2)2CH2N), 6.86ꢀ6.90 (m, 2H, ArH), 7.17 (br s, 1H, NH),
7.30ꢀ7.34 (m, 1H, 6-H), 7.53ꢀ7.57 (m, 2H, ArH), 7.66ꢀ7.71 (m, 2H,
2-H), 7.82 (dd, 1H, J = 8.4, 1.2 Hz, 5-H), 8.06 (dd, 1H, J = 8.4, 0.4 Hz,
5-H). 13C NMR (100 MHz, CDCl3): 12.53, 23.04, 27.17 (2C), 53.67
(2C), 58.82, 66.90, 73.84, 107.90, 110.12, 118.19 (2C), 120.01, 123.95,
Calcd for C24H25ClN4O2 0.5H2O: C, 64.64; H, 5.88; N, 12.56. Found:
3
4455
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
124.45, 127.06 (2C), 129.11, 129.87, 131.04, 140.61, 141.63, 144.46,
153.31, 160.08, 163.43. Anal. Calcd for C25H28N4O3 1.2H2O: C,
3
146.81, 153.70, 160.75. Anal. Calcd for C27H29ClN4O3 0.3H2O: C,
66.12; H, 6.75; N, 12.34. Found: C, 66.28; H, 6.82; N, 12.08. HRMS
(ESI) calcd for C25H29N4O3 [M þ H]þ 433.2240, found 433.2243.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-2-(Pyrrolidin-1-yl)ethyloxime (15e). 15e was
3
65.06; H, 5.99; N, 11.24. Found: C, 64.96; H, 6.25; N, 11.07. HRMS
(ESI) calcd for C27H30ClN4O3 [M þ H]þ 493.2006, found 493.2004.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phe-
nyl)ethanone O-2-Aminoethyloxime (15a). 15a was obtained
from 1-[4-(7-methoxyfuro[2,3-b]quinolin-4-ylamino)phenyl]ethan-
obtained from 11 and 2-pyrrolidin-1-ylethoxyamine HCl as described
3
for 13a: 81% yield. Mp: 123ꢀ124 °C. IR (KBr): 3244, 1585, 1525. UV
one (11)14 and 2-aminoethoxyamine HCl as described for 13a: 66%
(MeOH): 362 (4.28), 260 (4.50), 210 (4.54). H NMR (400 MHz,
1
3
yield. Mp: 91ꢀ93 °C. IR (KBr): 3219, 1581, 1517. UV (MeOH): 358
(4.22), 248 (4.44), 212 (4.48). 1H NMR (400 MHz, DMSO-d6): 2.22
(s, 3H, CH3), 2.88 (t, 2H, J = 5.8 Hz, OCH2CH2N), 3.92 (s, 3H,
OCH3), 4.12 (t, 2H, J = 5.8 Hz, OCH2CH2N), 6.08 (d, 1H, J = 2.4
Hz, 3-H), 7.13ꢀ7.19 (m, 3H, 6-H, ArH), 7.29 (d, 1H, J = 2.4 Hz,
2-H), 7.66ꢀ7.69 (m, 2H, ArH), 7.74 (d, 1H, J = 2.8 Hz, 8-H), 8.27
(d, 1H, J = 9.6 Hz, 5-H), 9.48 (br s, 1H, NH). 13C NMR (100 MHz,
DMSO-d6): 12.20, 40.72, 55.35, 75.17, 103.70, 105.72, 106.75,
113.14, 115.49, 120.69 (2C), 124.39, 126.59 (2C), 130.28, 141.47,
142.06, 142.73, 147.70, 153.70, 160.09, 163.44. HRMS (ESI) calcd
for C22H23N4O3 [M þ H]þ 391.1770, found 391.1769.
DMSO-d6): 1.69ꢀ1.72 (m, 4H, Pyr-H), 2.20 (s, 3H, CH3), 2.60 (br s,
4H, Pyr-H), 2.83 (t, 2H, J = 5.6 Hz, OCH2CH2N), 3.91 (s, 3H, OCH3),
4.24 (t, 2H, J = 6.0 Hz, OCH2CH2N), 6.08 (d, 1H, J = 2.8 Hz, 3-H),
7.13ꢀ7.18 (m, 3H, 6-H, ArH), 7.28 (d, 1H, J = 2.8 Hz, 2-H), 7.66ꢀ7.68
(m, 2H, ArH), 7.74 (d, 1H, J = 2.4 Hz, 5-H), 8.25 (d, 1H, J = 9.2 Hz,
8-H), 9.47(br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6): 12.33,
23.11 (2C), 54.13 (2C), 54.28, 55.40, 72.39, 103.73, 105.77, 106.75,
113.147, 115.56, 120.69 (2C), 124.42, 126.65 (2C), 130.21, 141.47,
142.13, 142.78, 147.73, 153.64, 160.12, 163.46. Anal. Calcd for
C26H28N4O3 1.2H2O: C, 66.99; H, 6.57; N, 12.02. Found: C, 67.12;
3
H, 6.73; N, 11.73. HRMS (ESI) calcd for C26H29N4O3 [M þ H]þ
445.2240, found 445.2241.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-2-(Dimethylamino)ethyloxime (15b). 15b
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-2-(Piperidin-1-yl)ethyloxime (15f). 15f was
was obtained from 11 and 2-dimethylaminoethoxyamine HCl as
3
described for 13a: 88% yield. Mp: 150ꢀ152 °C. IR (KBr): 3256,
1580, 1518. UV (MeOH): 360 (4.26), 250 (4.47), 210 (4.50). 1H NMR
(400 MHz, CDCl3): 2.26 (s, 3H, CH3), 2.36 (s, 6H, N(CH3)2), 2.75
(t, 2H, J = 5.8 Hz, OCH2CH2N), 3.95 (s, 3H, OCH3), 4.34 (t, 2H, J =
5.8 Hz, OCH2CH2N), 6.16 (d, 1H, J = 2.4 Hz, 3-H), 6.95 (br s, 1H,
NH), 7.10ꢀ7.15 (m, 3H, 6-H, ArH), 7.39 (d, 1H, J = 2.4 Hz, 2-H), 7.40
(d, 1H, J = 2.8 Hz, 8-H), 7.65ꢀ7.68 (m, 2H, ArH), 7.92 (d, 1H, J = 9.2
Hz, 5-H). 13C NMR (100 MHz, CDCl3): 12.70, 45.85 (2C), 55.48,
58.17, 72.21, 104.80, 105.74, 107.20, 113.24, 116.74, 120.72 (2C),
122.04, 127.04 (2C), 131.86, 140.47, 141.80, 141.87, 148.04, 154.04,
obtained from 11 and 2-piperidin-1-ylethoxyamine HCl as described
3
for 13a: 72% yield. Mp: 116ꢀ119 °C. IR (KBr): 3221, 1618, 1585,
1526. UV (MeOH): 362 (4.35), 260 (4.57), 210 (4.59). 1H NMR (400
MHz, DMSO-d6): 1.35ꢀ1.50 (m, 6H, Pip-H), 2.18 (s, 3H, CH3), 2.42
(m, 4H, Pip-H), 2.62 (t, 2H, J = 5.8 Hz, OCH2CH2N), 3.92 (s, 3H,
OCH3), 4.22 (t, 2H, J = 6.0 Hz, OCH2CH2N), 6.07 (d, 1H, J = 2.8 Hz,
3-H), 7.12ꢀ7.17 (m, 3H, 6-H, ArH), 7.29 (d, 1H, J = 2.8 Hz, 2-H),
7.65ꢀ7.68 (m, 2H, ArH), 7.74 (d, 1H, J = 2.8 Hz, 5-H), 8.25 (d, 1H, J =
9.2 Hz, 8-H), 9.46 (br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6):
12.26, 23.86, 25.54 (2C), 54.40 (2C), 55.36, 57.34, 71.57, 103.70,
105.73, 106.75, 113.14, 115.49, 120.68 (2C), 124.37, 126.59 (2C),
130.24, 141.45, 142.07, 142.72, 147.70, 153.48, 160.09, 163.44. HRMS
(ESI) calcd for C27H31N4O3 [M þ H]þ 459.2396, found 459.2395.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-2-Morpholinoethyloxime (15g). 15g was ob-
160.57, 163.85. Anal. Calcd for C24H26N4O3 0.5H2O: C, 67.43; H,
3
6.37; N, 13.11. Found: C, 67.43; H, 6.58; N, 12.83. HRMS (ESI) calcd
for C24H27N4O3 [M þ H]þ 419.2083, found 419.2086.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-3-Aminopropyloxime (15c). 15c was obtained
from 11 and 3-aminopropoxyamine HCl as described for 13a: 68%
tained from 11 and 2-morpholinoethoxyamine HCl as described for
3
3
yield as a light yellow liquid. IR (KBr): 3220, 1582, 1518. UV (MeOH):
362 (4.12), 260 (4.35), 210 (4.40). 1H NMR (400 MHz, DMSO-d6):
1.82 (quin, 2H, J = 6.6 Hz, OCH2CH2CH2N), 2.20 (s, 3H, CH3), 2.73
(t, 2H, J = 6.8 Hz, OCH2CH2CH2N), 3.92 (s, 1H, OCH3), 4.19 (t, 2H,
J = 6.4 Hz, OCH2CH2CH2N), 6.08 (d, 1H, J = 2.4 Hz, 3-H), 7.12ꢀ7.18
(m, 3H, 6-H, ArH), 7.28 (d, 1H, J = 2.4 Hz, 2-H), 7.66ꢀ7.69 (m, 2H,
ArH), 7.74 (d, 1H, J = 2.8 Hz, 8-H), 8.28 (d, 1H, J = 9.6 Hz, 5-H), 9.50
(br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6): 12.11, 31.28, 37.87,
55.34, 71.14, 103.68, 105.72, 106.74, 113.14, 115.46, 120.68 (2C),
124.40, 126.54 (2C), 130.29, 141.47, 142.05, 142.71, 147.70, 153.36,
160.08, 163.43. HRMS (ESI) calcd for C23H25N4O3 [M þ H]þ
405.1927, found 405.1926.
13a: 80% yield. Mp: 148ꢀ149 °C. IR (KBr): 3208, 1617, 1578, 1524.
UV (MeOH): 362 (4.32), 262 (4.56), 246 (4.53), 206 (4.61). 1H NMR
(400 MHz, DMSO-d6): 2.18 (s, 3H, CH3), 2.43ꢀ2.46 (m, 4H, Mor-
H), 2.64 (t, 2H, J = 6.0 Hz, OCH2CH2N), 3.57 (m, 4H, Mor-H), 3.91
(s, 3H, OCH3), 4.24 (t, 2H, J = 6.0 Hz, OCH2CH2N), 6.07 (d, 1H, J =
2.8 Hz, 3-H), 7.137.18 (m, 3H, 6-H, ArH), 7.28 (d, 1H, J = 2.4 Hz,
2-H), 7.65ꢀ7.68 (m, 2H, ArH), 7.74 (d, 1H, J = 2.8 Hz, 5-H), 8.25 (d,
1H, J = 9.6 Hz, 8-H), 9.46 (br s, 1H, NH). 13C NMR (100 MHz,
DMSO-d6): 12.33, 53.72 (2C), 55.40, 57.10, 66.24 (2C), 71.43, 103.72,
105.77, 106.75, 113.16, 115.56, 120.70 (2C), 124.41, 126.63 (2C),
130.24, 141.47, 142.12, 142.75, 147.73, 153.60, 160.12, 163.46. Anal.
Calcd for C26H28N4O4: C, 67.81; H, 6.13; N, 12.16. Found: C, 67.98;
H, 6.27; N, 11.71. HRMS (ESI) calcd for C26H29N4O4 [M þ H]þ
461.2189, found 461.2187.
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-3-(Dimethylamino)propyloxime (15d). 15d
was obtained from 11 and 3-dimethylaminopropoxyamine HCl as
(E)-1-(4-(7-Methoxyfuro[2,3-b]quinolin-4-ylamino)phen-
yl)ethanone O-4-Morpholinobutyloxime (15h). 15h was ob-
3
described for 13a: 79% yield. Mp: 95ꢀ97 °C. IR (KBr): 3327, 1580,
1516. UV (MeOH): 364 (4.32), 264 (4.60), 206 (4.61). 1H NMR (400
MHz, DMSO-d6): 1.82 (quin, 2H, J = 6.6 Hz, OCH2CH2CH2N), 2.18
(s, 6H, N(CH3)2), 2.19 (s, 3H, CH3), 2.37 (t, 2H, J = 7.2 Hz,
OCH2CH2CH2N), 3.92 (s, 1H, OCH3), 4.15 (t, 2H, J = 6.4 Hz,
OCH2CH2CH2N), 6.08 (d, 1H, J = 2.8 Hz, 3-H), 7.13ꢀ7.19 (m, 3H,
6-H, ArH), 7.29 (d, 1H, J = 2.4 Hz, 2-H), 7.66ꢀ7.68 (m, 2H, ArH),
7.74 (d, 1H, J = 2.8 Hz, 8-H), 8.27 (d, 1H, J = 9.2 Hz, 5-H), 9.47 (br s,
1H, NH). 13C NMR (100 MHz, DMSO-d6): 12.11, 26.81, 44.97 (2C),
55.34, 55.67, 71.60, 103.68, 105.72, 106.75, 113.13, 115.46, 120.69
(2C), 124.38, 126.54 (2C), 130.33, 141.47, 142.05, 142.68, 147.70,
tained from 11 and 4-morpholinobutoxyamine HCl as described for
3
13a: 71% yield. Mp: 100ꢀ102 °C. IR (KBr): 3211, 1578, 1519. UV
1
(MeOH): 362 (4.35), 260 (4.56), 210 (4.57). H NMR (400 MHz,
CDCl3): 1.60ꢀ1.86 (m, 2H, OCH2(CH2)2CH2N), 2.25 (s, 3H, CH3),
2.39ꢀ2.46 (m, 6H, Mor-H, OCH2(CH2)2CH2N), 3.72ꢀ3.74 (m, 4H,
Mor-H), 3.95 (s, 3H, OCH3), 4.22 (t, 2H, J = 6.4 Hz, OCH2-
(CH2)2CH2N), 6.15 (d, 1H, J = 2.8 Hz, 3-H), 6.90 (br s, 1H, NH),
7.10 (d, 1H, J = 2.4 Hz, 6-H), 7.12ꢀ7.15 (m, 2H, ArH), 7.39 (d, 1H, J =
2.8 Hz, 2-H), 7.40 (d, 1H, J = 2.4 Hz, 5-H), 7.65ꢀ7.68 (m, 2H, ArH),
7.91 (d, 1H, J = 9.6 Hz, 8-H). 13C NMR (100 MHz, CDCl3): 12.55,
4456
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
23.06, 27.18, 53.68 (2C), 55.48, 58.82, 66.91 (2C), 73.92, 104.70,
105.74, 107.18, 113.17, 116.73, 120.79 (2C), 121.98, 126.98 (2C),
132.05, 140.48, 141.74, 141.77, 148.02, 153.63, 160.56, 163.85. Anal.
Calcd for C28H32N4O4: C, 68.83; H, 6.60; N, 11.47. Found: C, 68.94;
H, 6.81; N, 11.04. HRMS (ESI) calcd for C28H33N4O4 [M þ H]þ
489.2502, found 489.2503.
110.13, 114.80, 117.18, 118.15 (2C), 125.66, 127.08 (2C), 130.95, 139.38,
141.68, 144.43, 149.06, 153.80, 161.01, 161.39. Anal. Calcd for
C24H25ClN4O3 1.0H2O: C, 61.91; H, 6.03; N, 11.55. Found: C, 61.61; H,
3
6.34; N, 11.57. HRMS (ESI) calcd for C25H28ClN4O3 [Mþ H]þ 467.1850,
found 467.1851.
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-(Pyrrolidin-1-yl)ethyloxime (16e).
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-Aminoethyloxime (16a). 16a was
obtained from 1-[4-(3-chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
16e was obtained from 12 and 2-pyrrolidin-1-ylethoxyamine HCl as
3
described for 13a: 98% yield. Mp: 116ꢀ117 °C. IR (KBr): 3137, 1617,
1580, 1520. UV (MeOH): 374 (4.14), 344 (4.13), 246 (4.52), 206
(4.58). 1H NMR (400 MHz, CDCl3): 1.67ꢀ1.70 (m, 4H, Pyr-H), 2.13
(s, 3H, CH3), 2.50ꢀ2.55 (m, 4H, Pyr-H), 2.76ꢀ2.79 (m, 2H,
OCH2CH2N), 4.19 (t, 2H, J = 6.0 Hz, OCH2CH2N), 6.84ꢀ6.88 (m,
2H, ArH), 7.20 (dd, 1H, J = 9.4, 2.6 Hz, 6-H), 7.37 (d, 1H, J = 2.6 Hz,
8-H), 7.48ꢀ7.52 (m, 2H, ArH), 8.12 (d, 1H, J = 9.6 Hz, 5-H), 8.24
(s, 1H, 2-H), 9.13 (br s, 1H, NH). 13C NMR (100 MHz, CDCl3): 12.22,
23.09 (2C), 54.07 (2C), 54.31, 55.57, 72.33, 106.72, 107.57, 109.94,
115.70 (2C), 116.66, 117.28, 124.84, 126.84 (2C), 127.62, 140.65,
141.16, 147.08, 148.04, 153.59, 160.82, 161.34. Anal. Calcd for
no)phenyl]ethanone (12)14 and 2-aminoethoxyamine HCl as de-
3
scribed for 13a: 98% yield. Mp: 108ꢀ110 °C. IR (KBr): 3133, 1580,
1520. UV (MeOH): 374 (4.15), 246 (4.49), 210 (4.47). 1H NMR (400
MHz, DMSO-d6): 2.14 (s, 3H, CH3), 2.81 (t, 2H, J = 6.4 Hz,
OCH2CH2N), 3.94 (s, 3H, OCH3), 4.05 (t, 2H, J = 5.8 Hz,
OCH2CH2N), 6.85ꢀ6.87 (m, 2H, ArH), 7.20 (dd, 1H, J = 9.2, 2.4
Hz, 6-H), 7.37 (d, 1H, J = 2.4 Hz, 8-H), 7.49ꢀ7.52 (m, 2H, ArH), 8.11
(d, 1H, J = 9.2 Hz, 5-H), 8.24 (s, 1H, 2-H), 9.12 (br s, 1H, NH). 13C
NMR (100 MHz, DMSO-d6): 12.12, 41.00, 55.57, 75.65, 106.72, 107.53,
109.95, 115.74 (2C), 116.64, 117.26, 124.84, 126.80 (2C), 127.76,
140.67, 141.13, 147.02, 148.04, 153.59, 160.81, 161.35. HRMS (ESI)
calcd for C22H22ClN4O3 [M þ H]þ 425.1380, found 425.1382.
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-(Dimethylamino)ethyloxime (16b).
C26H27ClN4O3 0.1HCl: C, 64.70; H, 5.66; N, 11.61. Found: C,
3
64.75; H, 6.28; N, 11.29. HRMS (ESI) calcd for C26H28ClN4O3
[M þ H]þ 479.1850, found 479.1852.
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-(Piperidin-1-yl)ethyloxime (16f).
16b was obtained from 12 and 2-dimethylaminoethoxyamine HCl as
3
described for 13a: 88% yield. Mp: 102ꢀ104 °C. IR (KBr): 3130, 1581,
1518. UV (MeOH): 374 (4.19), 248 (4.55), 210 (4.55). 1H NMR (400
MHz, CDCl3): 2.21 (s, 3H, CH3), 2.33 (s, 6H, N(CH3)2), 2.70 (t, 2H, J =
6.0 Hz, OCH2CH2N), 3.95 (s, 3H, OCH3), 4.30 (t, 2H, J = 6.0 Hz,
OCH2CH2N), 6.87ꢀ6.89 (m, 2H, ArH), 6.96 (dd, 1H, J = 9.4, 2.6 Hz,
6-H), 7.12 (br s, 1H, NH), 7.36 (d, 1H, J= 2.6 Hz, 8-H), 7.54ꢀ7.56 (m, 2H,
ArH), 7.61 (s, 1H, 2-H),7.68 (d, 1H, J = 9.4 Hz, 5-H). 13C NMR (100
MHz, CDCl3): 12.71, 45.94 (2C), 55.51, 58.22, 72.26, 106.14, 106.86,
110.11 (2C), 114.80, 117.19, 118.11, 125.66, 127.11 (2C), 130.83, 139.40,
141.64, 144.48, 149.04, 154.05, 161.00, 161.38. Anal. Calcd for
16f was obtained from 12 and 2-piperidin-1-ylethoxyamine HCl as
3
described for 13a: 98% yield. Mp: 126ꢀ127 °C. IR (KBr): 3135, 1617,
1580, 1521. UV (MeOH): 374 (4.13), 346 (4.12), 246 (4.47), 210
(4.47). 1H NMR (400 MHz, CDCl3): 1.34ꢀ1.38 (m, 2H, Pip-H),
1.44ꢀ1.51 (m, 4H, Pip-H), 2.11 (s, 3H, CH3), 2.37ꢀ2.46 (br s, 4H, Pip-
H), 3.60 (t, 2H, J = 5.6 Hz, OCH2CH2N), 3.93 (s, 3H, OCH3), 4.17
(t, 2H, J = 2.6 Hz, OCH2CH2N), 6.83ꢀ6.87 (m, 2H, ArH), 7.20
(dd, 1H, J = 9.4, 2.6 Hz, 6-H), 7.36 (d, 1H, J = 2.6 Hz, 8-H), 7.48ꢀ7.51
(m, 2H, ArH), 8.11 (d, 1H, J = 9.4 Hz, 5-H), 8.24 (s, 1H, 2-H), 9.12 (br s,
1H, NH). 13C NMR (100 MHz, CDCl3): 12.24, 23.86, 25.52 (2C),
54.40 (2C), 55.60, 57.39, 71.39, 106.73, 107.58, 109.96, 115.72 (2C),
116.67, 117.31, 124.86, 126.86 (2C), 127.67, 140.67, 141.18, 147.08,
C24H25ClN4O3 0.2H2O: C, 63.12; H, 5.62; N, 12.27. Found: C, 62.94;
3
H, 5.64; N, 12.07. HRMS (ESI) calcd for C24H26ClN4O3 [M þ H]þ
453.1693, found 453.1691.
148.06, 153.59, 160.84, 161.36. Anal. Calcd for C27H29ClN4O3 0.4
3
H2O: C, 64.83; H, 6.00; N, 11.20. Found: C, 64.78; H, 6.31; N, 11.08.
HRMS (ESI) calcd for C27H30ClN4O3 [M þ H]þ 493.2006, found
493.2005.
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-3-Aminopropyloxime (16c). 16c was
obtained from 12 and 3-aminopropoxyamine HCl as described for 13a:
3
43% yield. Mp: 115ꢀ116 °C. IR (KBr): 3386, 1584, 1513. UV (MeOH):
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-2-Morpholinoethyloxime (16g). 16g
1
374 (4.02), 344 (4.02), 246 (4.42), 206 (4.46). H NMR (400 MHz,
CDCl3): 1.90 (quin, 2H, J = 6.8 Hz, OCH2CH2CH2N), 2.14 (s, 3H,
CH3), 2.83 (t, 2H, J = 7.2 Hz, OCH2CH2CH2N), 3.94 (s, 3H, OCH3),
4.16 (t, 2H, J = 6.4 Hz, OCH2CH2CH2N), 6.84ꢀ6.77 (m, 2H, ArH),
7.21 (dd, 1H, J = 9.6, 2.4 Hz, 6-H), 7.37 (d, 1H, J = 2.4 Hz, 8-H),
7.47ꢀ7.52 (m, 2H, ArH), 8.14 (d, 1H, J = 9.6 Hz, 5-H), 8.24 (s, 1H,
2-H), 9.18 (br s, 1H, NH). 13C NMR (100 MHz, CDCl3): 12.10, 28.68,
36.91, 55.56, 70.39, 106.71, 107.56, 109.92, 115.69 (2C), 116.68, 117.55,
124.85, 126.43, 126.83 (2C), 140.63, 141.14, 147.13, 148.03, 153.81,
160.82, 161.34. HRMS (ESI) calcd for C23H24ClN4O3 [M þ H]þ
439.1537, found 439.1535.
was obtained from 12 and 2-morpholinoethoxyamine HCl as described
3
for 13a: 99% yield. Mp: 99ꢀ101 °C. IR (KBr): 3149, 1613, 1582, 1522.
UV (MeOH): 374 (4.12), 344 (4.11), 248 (4.55), 206 (4.63). 1H NMR
(400 MHz, CDCl3): 2.13 (s, 3H, CH3), 2.52ꢀ2.63 (br s, 4H, Mor-H),
2.72 (br s, 2H, OCH2CH2N), 3.54ꢀ3.68 (m, 4H, Mor-H), 4.24 (m, 2H,
OCH2CH2N), 6.85ꢀ6.87 (m, 2H, ArH), 7.21 (dd, 1H, J = 9.4, 2.6 Hz,
6-H), 7.37 (d, 1H, J = 2.6 Hz, 8-H), 7.50ꢀ7.52 (m, 2H, ArH), 8.12
(d, 1H, J = 9.4 Hz, 5-H), 8.24 (s, 1H, 2-H), 9.15 (br s, 1H, NH). 13C
NMR (100 MHz, CDCl3): 12.26, 53.42 (2C), 55.58, 56.78, 65.84 (2C),
71.26, 106.73, 107.60, 109.94, 115.70 (2C), 116.68, 117.27, 124.85,
126.88 (2C), 127.55, 140.65, 141.16, 147.13, 148.04, 153.89, 160.83,
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-3-(Dimethylamino)propyloxime (16d).
161.34. Anal. Calcd for C26H27ClN4O4 2.0H2O: C, 58.81; H, 5.88; N,
3
10.55. Found: C, 58.55; H, 6.15; N, 10.36. HRMS (ESI) calcd for
16d was obtained from 12 and 3-dimethylaminopropoxyamine HCl as
3
C26H28ClN4O4 [M þ H]þ 495.1799, found 495.1801.
described for 13a: 79% yield. Mp: 96ꢀ98 °C. IR (KBr): 3247, 1615, 1583,
1
1523. UV (MeOH): 374(4.20), 346 (4.17), 248 (4.55), 210 (4.56). H
(E)-1-(4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylami-
no)phenyl)ethanone O-4-Morpholinobutyloxime (16h). 16h
NMR (400 MHz, CDCl3): 1.85ꢀ1.96 (m, 2H, OCH2CH2CH2N), 2.20 (s,
3H, CH3), 2.28 (s, 6H, N(CH3)2), 2.44 (t, 2H, J = 7.6 Hz,
OCH2CH2CH2N), 3.95 (d, 3H, OCH3), 4.22 (t, 2H, J = 6.4 Hz,
OCH2CH2CH2N), 6.86ꢀ6.90 (m, 2H, ArH), 6.96 (dd, 1H, J = 9.6, 2.6
Hz, 6-H), 7.12 (br s, 1H, NH), 7.36 (d, 1H, J = 2.6 Hz, 8-H), 7.54ꢀ7.56 (m,
2H, ArH), 7.61 (s, 1H, 2-H), 7.69 (d, 1H, J = 9.6 Hz, 5-H). 13C NMR (100
MHz, CDCl3): 12.48, 27.40, 45.33 (2C), 55.50, 56.49, 72.20, 106.11, 106.89,
was obtained from 12 and 4-morpholinobutoxyamine HCl as described
3
for 13a: 98% yield. Mp: 124ꢀ126 °C. IR (KBr): 3142, 1614, 1585, 1515.
UV (MeOH): 374 (4.06), 344 (4.06), 246 (4.48), 206 (4.51). 1H NMR
(400 MHz, CDCl3): 1.54ꢀ1.78 (m, 4H, OCH2(CH2)2CH2N), 2.20
(s, 3H, CH3), 2.33ꢀ2.46 (m, 6H, OCH2(CH2)2CH2N, Mor-H),
3.72ꢀ3.74 (m, 4H, Mor-H), 3.95 (s, 3H, OCH3), 4.19 (t, 2H, J = 6.4 Hz,
4457
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
OCH2(CH2)2CH2N), 6.86ꢀ6.89 (m, 2H, ArH), 6.96 (dd, 1H, J = 9.4,
2.6 Hz, 6-H), 7.12 (br s, 1H, NH), 7.36 (d, 1H, J = 2.6 Hz, 8-H),
7.54ꢀ7.56 (m, 2H, ArH), 7.61 (s, 1H, 2-H), 7.70 (d, 1H, J = 9.4 Hz,
5-H). 13C NMR (100 MHz, CDCl3): 12.54, 23.02, 27.16, 53.65 (2C),
55.51, 58.81, 66.88 (2C), 73.82, 106.11, 106.86, 110.11, 114.78, 117.18,
118.16 (2C), 125.65, 127.06 (2C), 130.95, 139.39, 141.66, 144.43,
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)be-
nzamide (23). This compound was obtained as a light yellow solid in
59% yield. Mp: 284ꢀ286 °C. IR (KBr): 3396, 2362, 1616. UV (MeOH):
1
347 (4.19), 251 (4.53), 212 (4.50). H NMR (400 MHz, DMSO-d6):
3.95 (s, 3H, OCH3), 6.83ꢀ6.85 (m, 2H, ArH), 7.09 (br s, 1H, NH), 7.22
(dd, 2H, J = 9.2, 2.6 Hz, 6-H), 7.40 (d, 1H, J = 2.8 Hz, 8-H), 7.72ꢀ7.74
(m, 3H, ArH and NH), 8.10 (d, 1H, J = 9.2 Hz, 5-H), 8.27 (s, 1H, 2-H),
9.24 (br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6): 55.62, 106.76,
108.27, 109.92, 114.68 (2C), 117.01, 117.52, 124.85, 125.38, 129.02
(2C), 140.04, 141.46, 148.04, 148.94, 160.89, 161.31, 167.64. HRMS
(ESI) calcd for C19H15ClN3O3 [M þ H]þ 368.0802, found 368.0801.
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)-N-
methylbenzamide (24). This compound was obtained as a pale
yellow solid in 60% yield. Mp: 162ꢀ163 °C. IR (KBr): 3395, 2375, 1613,
1507. UV (MeOH): 348 (3.97), 250 (4.15), 208 (4.15). 1H NMR (400
MHz, CDCl3): 2.998 (d, 3H, J = 2.8 Hz, CH3), 3.96 (s, 3H, OCH3), 6.10
(br s, 1H, NH), 6.85ꢀ6.88 (m, 2H, ArH), 7.00 (dd, 1H, J = 9.2, 2.4 Hz,
6-H), 7.11 (br s, 1H, NH), 7.38 (d, 1H, J = 2.8 Hz, 8-H), 7.63 (s, 1H,
2-H), 7.65ꢀ7.68 (m, 2H, ArH), 7.69 (d, 1H, J = 9.6 Hz, 5-H). 13C NMR
(100 MHz, CDCl3): 26.80, 55.56, 106.89, 110.41, 115.37, 117.08 (2C),
117.68, 125.31, 127.89, 128.33 (2C), 128.52, 139.86, 140.70, 146.76,
149.04, 153.72, 161.00, 161.38. Anal. Calcd for C28H31ClN4O4 0.7
3
H2O: C, 62.78; H, 6.10; N, 10.46. Found: C, 62.66; H, 6.40; N, 10.51.
HRMS (ESI) calcd for C28H31ClN4O4 [M þ H]þ 523.2112, found
523.2115.
4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)benzenesulfo-
namide (19). To a solution of 3,4-dichlorofuro[2,3-b]quinoline37
(17, 0.48 g, 2 mmol) and 4-aminobenzenesulfonamide (0.52 g, 3 mmol)
in EtOH/H2O 2:1 (15 mL) was added concentrated HCl until pH 6
resulted. The mixture was heated to reflux for 24 h (TLC monitoring),
and then the solvent was evaporated in vacuo to give a residual solid.
After addition of iceꢀwater (40 mL), the mixture was was neutralized
with 1 N NaOH solution. The resulting precipitate was collected and
purified by flash column chromatography (FC, silica gel CH2Cl2) to
give 19 (0.40 g, 54%). Mp: 210ꢀ212 °C. IR (KBr): 3448. UV (MeOH):
371 (3.44), 236 (3.95), 209 (3.98). 1H NMR (400 MHz, DMSO-d6):
6.89ꢀ6.93 (m, 2H, ArH), 7.12 (br s, 2H, NH2), 7.58ꢀ7.63 (m, 3H,
6-H, ArH), 7.81ꢀ7.85 (m, 1 H, 7-H), 8.04ꢀ8.06 (m, 1H, 5-H),
8.19ꢀ8.22 (m, 1H, 8-H), 8.42 (s, 1H, 2-H), 9.41 (br s, 1H, NH). 13C
NMR (100 MHz, DMSO-d6): 109.83, 110.98, 114.60 (2C), 122.43,
123.43, 125.02, 127.39 (2C), 128.47, 130.33, 134.62, 139.72, 143.20,
145.82, 149.41, 160.65. HRMS (ESI) calcd for C17H13ClN3O3S
[M þ H]þ 374.0366, found 374.0364.
148.90, 161.15, 161.31, 167.55. Anal. Calcd for C20H16ClN3O3 1.2
3
H2O: C, 59.54; H, 4.60; N, 10.42. Found: C, 59.81; H, 4.67; N, 10.20.
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)-
N-(2-hydroxyethyl)benzamide (25). This compound was ob-
tained as a pale yellow solid in 56% yield. Mp: 145ꢀ147 °C. IR
(KBr): 3337, 2928, 2361, 1717. UV (MeOH): 348 (4.02), 210 (4.25).
1H NMR (400 MHz, DMSO): 3.27ꢀ3.32 (m, 2H, NHCH2CH2O),
3.50 (t, 2H, J = 6.0 Hz, NHCH2CH2O), 3.94 (s, 3H, OCH3),
6.84ꢀ3.86 (m, 2H, ArH), 7.22 (dd, 2H, J = 9.2, 2.4 Hz, 6-H), 7.38
(d, 1H, J = 2.4 Hz, 8-H), 7.70ꢀ7.72 (m, 2H, ArH), 8.11 (d, 1H, J = 8.8
Hz, 5-H), 8.19 (t, 1H, J = 5.6 Hz, NH), 8.26 (s, 1H, 2-H), 9.24 (s, 1H,
NH). 13C NMR (100 MHz, DMSO): 42.08, 55.65, 59.96, 106.78,
108.17, 109.96, 114.84 (2C), 116.97, 117.54, 124.88, 125.72, 128.67
(2C), 140.32, 141.45, 148.08, 148.81, 160.93, 161.36, 166.05. Anal.
Compounds 20ꢀ27 were prepared from 17 and 18 by the same
procedures as described for 19.
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)be-
nzenesulfonamide (20). This compound was obtained as a white
solid in 53% yield. Mp: 199ꢀ200 °C. IR (KBr): 3345, 1619, 1586, 1504.
UV (MeOH): 346 (4.19), 256 (4.58), 211 (4.45). 1H NMR (400 MHz,
DMSO-d6): 3.95 (s, 3H, OCH3), 6.87ꢀ6.90 (m, 2H, ArH), 7.12 (br s,
2H, NH2), 7.24 (dd, 1H, J = 9.4, 2.4 Hz, 6-H), 7.41 (d, 1H, J = 2.4 Hz,
8-H), 7.59ꢀ7.63 (m, 2H, ArH), 8.06 (d, 1H, J = 9.6 Hz, 5-H), 8.31
(s, 1H, 2-H), 9.34 (br s, 1H, NH). 13C NMR (100 MHz, DMSO-d6):
55.65, 106.80, 109.04, 109.80, 114.48 (2C), 117.36, 117.83, 124.73,
127.37 (2C), 134.49, 139.68, 141.82, 148.04, 149.37, 160.94, 161.22.
HRMS (ESI) calcd for C18H15ClN3O4S [M þ H]þ 404.0472, found
404.0470.
Calcd for C21H18ClN3O4 0.8H2O: C, 59.17; H, 4.63; N, 9.86.
3
Found: C, 59.21; H, 4.70; N, 9.80.
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)-
N-(2-(dimethylamino)ethyl)benzamide (26). This com-
pound was obtained as a yellow solid in 60% yield. Mp: 128ꢀ
130 °C. 1H NMR (400 MHz, CDCl3): 2.30 (s, 6H, N(CH3)2), 2.57
(t, 2H, J = 5.6 Hz, NCH2CH2N(CH3)2), 3.53 (m, 2H, NCH2CH2N-
(CH3)2), 3.95 (s, 3H, OCH3), 6.84ꢀ6.87 (m, 2H, ArH), 6.96ꢀ7.02
(m, 2H, NH, 6-H), 7.16 (br s, 1H, NH), 7.37 (d, 1H, J = 2.4 Hz, 8-H),
8.62 (s, 1H, 2-H), 7.70ꢀ7.74 (m, 3H, 5-H, ArH). 13C NMR (100
MHz, CDCl3): 36.91, 45.01 (2C), 55.53, 57.87, 106.85, 107.08,
110.14, 115.43, 116.91 (2C), 117.62, 125.32, 127.66, 128.55 (2C),
139.80, 140.72, 146.82, 148.87, 161.10, 161.30, 166.84. Anal. Calcd
for C23H23ClN4O3 0.2H2O 1.0HCl: C, 57.67; H, 5.13; N, 11.70.
4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)benzoic Acid
(21). This compound was obtained as a white solid in 53% yield. Mp:
265ꢀ267 °C. IR (KBr): 3285, 1580. UV (MeOH): 377 (4.13), 261
(4.33), 236 (4.50), 211 (4.43). 1H NMR (400 MHz, DMSO-d6):
6.84ꢀ6.88 (m, 2H, ArH), 7.57ꢀ7.61 (m, 1H, 6-H), 7.74ꢀ7.77 (m,
2H, ArH), 7.80ꢀ7.84 (m, 1H, 7-H), 8.03 (d, 1H, J = 8.4 Hz, 5-H), 8.21
(dd, 1H, J = 8.4, 0.8 Hz, 8-H), 8.40 (s, 1H, 2-H), 9.45 (br s, 1H, NH). 13C
NMR (100 MHz, DMSO-d6): 109.86, 110.80, 114.58 (2C), 121.44,
122.36, 123.46, 124.95, 128.41, 130.30, 131.06 (2C), 139.73, 143.12,
145.79, 150.47, 160.63, 167.19. HRMS (ESI) calcd for C18H12ClN2O3
[M þ H]þ 339.0536, found 339.0533.
3
3
Found: C, 57.55; H, 5.16; N, 11.54.
4-(3-Chloro-7-methoxyfuro[2,3-b]quinolin-4-ylamino)-
N-(3-(dimethylamino)propyl)benzamide (27). This com-
pound was obtained as a yellow solid in 65% yield. Mp: 119ꢀ
120 °C. IR (KBr): 3428, 1503, 1262. UV (MeOH): 348 (3.98), 250
(4.13), 208 (4.21). 1H NMR (400 MHz, DMSO): 1.79ꢀ1.86 (m, 2H,
NCH2CH2CH2N), 2.55 (s, 6H, N(CH3)2), 2.86ꢀ2.90 (m, 2H,
NCH2CH2CH2N(CH3)2), 3.26ꢀ3.31 (m, 2H, NCH2CH2CH2N-
(CH3)2), 3.94 (s, 3H, OCH3), 6.85ꢀ6.87 (m, 2H, ArH), 7.22 (dd,
1H, J = 9.2, 2.8 Hz, 6-H), 7.39 (d, 1H, J = 2.4 Hz, 8-H), 7.70ꢀ7.73 (d,
2H, ArH), 8.12 (d, 2H, J = 9.2 Hz, 5-H), 8.27 (s, 1H, 2-H), 8.43 (t,
1H, J = 5.6 Hz, NH), 9.30 (br s, 1H, NH). 13C NMR (100 MHz,
DMSO): 25.11, 36.51, 42.76 (2C), 55.14, 55.61, 106.73, 108.23,
109.89, 114.71 (2C), 116.99, 117.50, 124.85, 125.38, 128.64 (2C),
140.20, 141.45, 148.03, 148.92, 160.87, 161.29, 166.04. Anal. Calcd for
4-(3-Chlorofuro[2,3-b]quinolin-4-ylamino)benzamide (22).
This compound was obtained as a light yellow solid in 62% yield. Mp:
198ꢀ200 °C. IR (KBr): 3444, 3363, 1638, 1603, 1583, 1524. UV (MeOH):
1
377 (3.98), 261 (4.20), 236 (4.35), 210 (4.30). H NMR (400 MHz,
DMSO-d6): 6.86ꢀ6.89 (m, 2H, ArH), 7.11 (br s, 1H, NH), 7.57ꢀ7.61 (m,
1H, 6-H), 7.73ꢀ7.84 (m, 4H, ArH, 7-H, and NH), 8.03 (dd, 1H, J = 8.4, 0.8
Hz, 5-H), 8.24 (dd, 1H, J = 8.4, 0.8 Hz, 8-H), 8.38 (s, 1H, 2-H), 9.32 (br s,
1H, NH). 13C NMR (100 MHz, DMSO-d6): 109.91, 110.09, 114.76 (2C),
122.06, 123.50, 124.70, 125.50, 128.37, 129.00 (2C), 130.20, 140.23,
142.76, 145.79, 148.92, 160.71, 167.61. HRMS (ESI) calcd for
C18H13ClN3O2 [M þ H]þ 338.0696, found 338.0694.
4458
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
C24H25ClN4O3 0.6H2O 1.0HCl: C, 57.63; H, 5.48; N, 11.20.
Found: C, 57.64; H, 5.54; N, 11.02.
attached. On the morning of implantation, mice were irradiated with 500
rads from a γ source. After preparation of the tumor syringes, the animals
were anesthetized with ketamine/xylazine (160/12 mg/kg, im; C.D.M.V.
Inc., Guelph, Ontario, Canada) and placed in the supine recumbent
position with head elevated slightly for implantation. The spine was
straightened by exerting traction on both head and tail. After a small
tracheostomy incision was made, the cannula was passed into the right
caudal lobe by inserting it into the trachea and advancing it gently in a
caudal direction at an angle of 10ꢀ20° to the axis of the trachea. When
resistance was encountered the cannula was withdrawn 1ꢀ2 mm. The
tumor tissue was then expelled and the cannula withdrawn. The wound
was closed with sterile wound clips and the animals returned to their
cages, dorsal side up, with upper body elevated on rolled-up sterile
drapes. Mice with lung cancer were then treated 13a orally for 2 weeks.
Nude mice were examined daily for signs of morbidity. Animal and
primary tumor weights were recorded and mean values calculated for
10 weeks.
3
3
Cell Lines and Culture Conditions. Cell lines were purchased
from Bioresource Collection and Research Center (Hsinchu, Taiwan).
Cancer cell lines were the following: lung cancer cell lines, NCI-H460,
A549, H1299, H661, and CL1ꢀ5; non-lung-cancer cell lines, 786-O,
AGS, PC3, BT483, HeLa, SAS, SKHep, and CE81T; normal fibroblast
cell lines, Hs68 and MRC-5, which were employed for determining their
IC50 values. Each cell line was maintained in standard medium and
grown as a monolayer in Dulbecco’s modified Eagle’s medium (DMEM)
containing 10% fetal bovine serum, 2 mM glutamine, 100 units/mL
penicillin, and 100 g/mL streptomycin. Cultures were maintained at
37 °C with 5% CO2 in a humidified atmosphere.
Cell Proliferation and Cell Viability MTT Assay. The experi-
mental procedures were similar as described previously.33
Solubility Measurements.38. Equilibrium solubilities were de-
termined by adding an excess amount of solid to the medium (water,
doubly distilled), followed by 5 min of sonification and overnight
equilibration by stirring at ambient temperature (25 ( 0.1 °C). The
samples were centrifuged, and aliquots were removed. Standard solu-
tions were prepared for each compound in order to quantify the
aforementioned saturated solutions, and reference curves were plotted
for each compound. The absorbance of each saturated and standard
solution was measured with a UV/vis spectrophotometer at a wave-
length that varied between 315 and 420 nm.
Statistical Analysis. Analyses were performed on a Macintosh
computer using a Statview statistical program (Abacus Concepts,
Berkeley, metastatic, orthotropic lung cancer model 159 CA). Primary
tumor sizes were compared by the KruskalꢀWallis test. Metastatic
incidences were compared using Fisher’s exact test. In all cases, P < 0.05
was considered to be significant.
’ AUTHOR INFORMATION
Single Dose Pharmacokinetic Studies. The tested compounds
(1, 13a, and 14a) were evaluated by Rosetta Pharmamate Co., Ltd.,
Taiwan (R.O.C.), and the experimental procedures were similar as
described previously.33
Corresponding Author
*For P.-J.L.: phone, (886) 7-5919000, extension 7717; fax,
(886) 6-3028049; e-mail, pjlu2190@mail.ncku.edu.tw. For
C.-C. T.: phone, (886) 7-3121101, extension 2123; fax, (886)
7-3125339; e-mail, tzengch@kmu.edu.tw.
Human Lung Cancer Xenograph Experiment (In Vivo
Tumoregenesis Assay). Compound 13a has been selected as a
new drug candidate because of its selective cytotoxicity, higher oral
bioavailability (57.1%), and moderate plasma half-life (3.4 h). Human
lung cancer cells NCI-H460 were grown in RPMI1640 with 10% NBS
until near confluence and then harvested by trypsinization. Cells (5 ꢁ
106) were then mixed with Matrigel (BD Biosciences) to achieve 40%
Matrigel in the final solution. The cell preparation was then injected
subcutaneously into the flanks of 6ꢀ8-week-old Balb/c nude mice. For
treatment, compound 13a was prepared in DMSO, 1.4% Tween 80, and
1% sodium carboxymethylcellulose (Sigma) normal saline solution; the
vehicle control was with the same mixture lacking 13a. On the basis of
the dose for acute toxicity, compound 13a was dosed at two different
concentrations (10 and 20 mg per day for ip administration; 60 and 120
mg per day for oral administration), together with the control group.
Subcutaneous tumors were measured with the standard clipper ruler
method. Final tumor weight at the end of the study was documented
after animal sacrifice and dissection of tumor tissue.
’ ACKNOWLEDGMENT
Financial support of this work by the National Science Council
of the Republic of China is gratefully acknowledged. We also
thank the National Center for High-Performance Computing for
providing computer resources and chemical database services.
’ ABBREVIATIONS USED
MDR, multidrug resistance; MTT, microculture tetrazolium; IC50,
concentration of 50% growth inhibition; SI, selectivity index; SAR,
structureꢀactivity relationship; DAR, daunorubicin; m-AMSA,
amsacrine
’ REFERENCES
(1) Atwell, G. J.; Cain, B. F.; Seelye, R. N. Potential antitumor agents.
12. 9-Anilinoacridine. J. Med. Chem. 1972, 15, 611–615.
(2) Denny, W. A.; Atwell, G. J.; Cain, B. F. J. Potential antitumor
agents. 26. Anionic congeners of 9-anilinoacridines. J. Med. Chem. 1978,
21, 5–10.
(3) Denny, W. A.; Cain, B. F.; Atwell, G. J.; Hansch, C.; Panthananickal,
A.; Leo, A. Potential antitumor agents. 36. Quantitative relationships
between experimental antitumor activity, toxicity, and structure for the
general class of 9-anilinoacridine antitumor agents. J. Med. Chem. 1982,
25, 276–315.
(4) Gamage, S. A.; Tepsiri, N.; Wilairat, P.; Wojcik, S. J.; Figgitt,
D. P.; Ralph, R. K.; Denny, W. A. Synthesis and in vitro evaluation of
9-anilino-3,6-acridines active against a multidrug-resistant strain of the
malaria parasite Plasmodium falciparum. J. Med. Chem. 1994,
37, 1486–1494.
(5) Gamage, S. A.; Figgitt, D. P.; Wojcik, S. J.; Ralph, R. K.; Ransijn,
A.; Mauel, J.; Yardley, V.; Snowdon, D.; Croft, S. L.; Denny, W. A.
Structureꢀactivity relationships for the antileishmanial and antitrypanosomal
Orthotropic Lung Cancer Model in Nude Mice. The efficacy
of 13a was investigated in orthotropic lung cancer model in nude mice
using H-1299 or Tumor fragments. These experiments were completed
and show that the lead compound has great efficacy in inhibiting tumor
growth in vivo. Tumor fragments (H-1299) for orthotopic implantation
were prepared by removing orthotopic donor tumors (0.5ꢀ1.0 g),
placing them into a sterile Petri dish and cutting viable portions of tumor
tissue into 1 mm diameter pieces using the “crossed scalpels” technique.
The pieces were mixed thoroughly, then weighed and divided into
approximately 50 mg portions. Each portion was loaded into the
proximal end of a 16-gauge, 2 in. long Teflon catheter (Becton
Dickinson, Sandy, UT) and forced through the catheter once using
the air pressure from a 1 mL syringe. This ensured that the tissue would
not obstruct the cannula when the endobronchial implantations were
performed. Each aliquot of tissue was then loaded into the proximal end
of a cannula for implantation. Then three drops of medium were added
to keep it moist and a 1 mL cannula containing 200 μL of air was
4459
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
activities of 10-substituted 9-anilinoacridines. J. Med. Chem. 1997,
40, 2634–2642.
(23) Kim, Y. Y.; Park, C. K.; S. K.; Phi, J. H.; Kim, J. H.; Kim, C. Y.;
Wang, K. C.; Cho, B. K. CKD-602, a camptothecin derivative, inhibits
proliferation and induces apoptosis in glioma cell lines. Oncol. Rep. 2009,
21, 1413–1419.
(24) Pettit, G. R.; Cragg, G. M.; Herald, D. L.; Schmidt, J. M.;
Lobavanijaya, P. Anti-neoplastic agents. 84. Isolation and structure of
combretastatin. Can. J. Chem. 1982, 60, 1347–1376.
(25) Nam, N. H. Combretastatin A-4 analogues as antimitotic
antitumor agents. Curr. Med. Chem. 2003, 10, 1697–1722.
(26) Xia, Y.; Yang, Z.-Y.; Xia, P.; Bastow, K. F.; Tachibana, Y.; Kuo,
S.-C.; Hamel, E.; Hackl, T.; Lee, K.-H. Antitumor agents. 181. Synthesis
and biological evaluation of 6,7,20,30,40-substituted-1,2,3,4-tetrahydro-2-
phenyl-4-quinolones as a new class of antimitotic antitumor agents.
J. Med. Chem. 1998, 41, 1155–1162.
(6) Baguley, B. C.; Denny, W. A.; Atwell, G. J.; Cain, B. F. Potential
antitumor agents. Part 35. Quantitative relationships between antitumor
(L1210) potency and DNA binding for 40-(9-acridinylamino)me-
thanesulfon-m-anisidide analogues. J. Med. Chem. 1981, 24, 520–525.
(7) Rewcastle, G. W.; Atwell, G. J.; Chambers, D.; Gaguley, B. C.;
Denny, W. A. Potential antitumor agents. 46. Structureꢀactivity rela-
tionships for acridine monosubstituted derivatives of the 4-carboxa-
mides. J. Med. Chem. 1986, 29, 472–477.
(8) Denny, W. A.; Atwell, G. J.; Rewcastle, G. W.; Baguley, B. C.
Potential antitumor agents. 49. 5-Substituted derivatives of N-[2-(di-
methylamino)ethyl]-9-aminoacridine-4-carboxamide with in vivo solid
tumor activity. J. Med. Chem. 1987, 30, 658–663.
(9) Su, T. L.; Chou, T. C.; Kim, J. Y.; Huang, J. T.; Ciszewska, G.;
Ren, W. Y.; Otter, G. M.; Sirotnak, F. M.; Watanabe, K. A. 9-Substituted
acridine derivatives with long half-life and potent antitumor activity:
synthesis and structureꢀactivity relationships. J. Med. Chem. 1995,
38, 3226–3235.
(10) Stanslas, J.; Hagan, D. J.; Ellis, M. J.; Turner, C.; Carmichael, J.;
Ward, W.; Hammonds, T. R.; Stevens, M. F. G. Antitumor polycyclic
acridines. 7. Synthesis and biological properties of DNA affinic tetra- and
pentacyclic acridines. J. Med. Chem. 2000, 43, 1563–1572.
(11) Chen, I. L.; Chen, Y. L.; Tzeng, C. C.; Chen, I. S. Synthesis and
cytotoxic evaluation of some 4-anilinofuro[2,3-b]quinoline derivatives.
Helv. Chim. Acta 2002, 85, 2214–2221.
(12) Zhao, Y. L.; Chen, Y. L.; Tzeng, C. C.; Chen, I. L.; Wang, T. C.;
Han, C. H. Synthesis and cytotoxic evaluation of 4-(phenylamino)furo-
[2,3-b]quinoline and 2-(furan-2-yl)-4-(phenylamino)quinoline deriva-
tives. Chem. Biodiversity 2005, 2, 205–214.
(13) Huang, Y. T.; Huang, D. M.; Guh, J. H.; Chen, I. L.; Tzeng,
C. C.; Teng, C. M. CIL-102 interacts with microtubule polymerization
and causes mitotic arrest following apoptosis in the human prostate
cancer PC-3 cell line. J. Biol. Chem. 2005, 280, 2771–2779.
(14) Chen, Y. L.; Chen, I. L.; Wang, T. C.; Han, C. H.; Tzeng, C. C.
Synthesis and anticancer evaluation of certain 4-anilinofuro[2,3-
b]quinoline and 4-anilinofuro[3,2-c]quinoline derivatives. Eur. J. Med.
Chem. 2005, 40, 928–934.
(15) Chen, Y. L.; Lin, H. C.; Yang, C. N.; Lu, P. J.; Tzeng, C. C.
Synthesis and antiproliferative evaluation of certain 4-anilino-7-
methoxyfuro[2,3-b]quinoline and 4-anilino-6-methoxyfuro[2,3-b]quin-
oline derivatives. Part 5. Chem. Biodiversity 2008, 4, 267–278.
(16) Rupp, C.; Steckel, H.; Mueller, B. W. Solubilization of poorly
water-soluble drugs by mixed micelles based on hydrogenated phos-
phatidylcholine. Int. J. Pharm. 2010, 395, 272–280.
(27) McGown, A. T.; Fox, B. W. Differential cytotoxicity of com-
bretastatin-A1 and combretastatin-A4 in 2 daunorubicin-resistant P388
cell lines. Cancer Chemother. Pharmacol. 1990, 26, 79–81.
(28) El-Zayat, A. A. E.; Degen, D.; Drabek, S.; Clark, G. M.; Pettit,
G. R.; Von Hoff, D. D. In vitro evaluation of the antineoplastic activity of
combretastatin-A-4, a natural product from Combretum-caffrum (acid
shrub). Anti-Cancer Drugs 1993, 4, 19–25.
(29) Ohsumi, K.; Nakagava, R.; Fukuda, Y.; Hatanaka, T.; Morinaga,
Y.; Nihei, U.; Ohishi, K.; Suga, Y.; Akiyama, Y.; Tsuji, T. Novel
combretastatin analogues effective against murine solid tumors: design
and structureꢀactivity relationships. J. Med. Chem. 1998, 41, 3022–3032.
(30) Bedford, S. B.; Quarterman, C. P.; Rathbone, D. L.; Slack, J. A.;
Griffin, R. J.; Stevens, M. F. G. Synthesis of water-soluble prodrugs of the
cytotoxic agent combretastatin A4. Bioorg. Med. Chem. Lett. 1996, 6,
157–160.
(31) Tseng, C. H.; Chen, Y. L.; Lu, P. J.; Yang, C. N.; Tzeng, C. C.
Synthesis and antiproliferative evaluation of certain indeno[1,
2-c]quinoline derivatives. Bioorg. Med. Chem. 2008, 16, 3153–3162.
(32) Tseng, C. H.; Chen, Y. L.; Chung, K. Y.; Cheng, C. M.; Wang,
C. H.; Tzeng, C. C. Synthesis and antiproliferative evaluation of
6-arylindeno[1,2-c]quinoline derivatives. Bioorg. Med. Chem. 2009,
17, 7465–7476.
(33) Tseng, C. H.; Tzeng, C. C.; Yang, C. L.; Lu, P. J.; Chen, H. L.;
Li, H. Y.; Chuang, Y. C.; Yang, C. N.; Chen, Y. L. Synthesis and
antiproliferative evaluation of certain indeno[1,2-c]quinoline deriva-
tives. Part 2. J. Med. Chem. 2010, 53, 6164–6179.
(34) Cerri, A.; Almirante, N.; Barassi, P.; Benicchio, A.; Fedrizzi, G.;
Ferrari, P.; Micheletti, R.; Quadri, L.; Ragg, E.; Rossi, R.; Santagostino,
M.; Schiavone, A.; Serra, F.; Zappavigna, M. P.; Melloni, P. 17β-O-
Aminoalkyloximes of 5β-androstane-3β,14β-diol with digitalis-like ac-
tivity: synthesis, cardiotonic activity, structureꢀactivity relationships,
and molecular modeling of the Naþ,Kþ-ATPase receptor. J. Med. Chem.
2000, 43, 2332–2349.
(17) Mueller, C. E. Prodrug approaches for enhancing the bioavail-
ability of drugs with low solubility. Chem. Biodiversity 2009, 6,
2071–2083.
(35) Silverstein, R. M.; Webster, F. X. 13C NMR Spectrometry. In
Spectrometric Identification of Organic Compounds, 6th ed.; Rose, N., Ed.;
John Wiley and Sons: New York, 1998; pp 217ꢀ249.
(18) Wall, M. E.; Wani, M. C.; Cook, C. E.; Palmer, K. H.; McPhail,
A. T.; Sim, G. A. Plant antitumor agents. I. The isolation and structure of
camptothecin, a novel alkaloidal leukemia and tumor inhibitor from
Camptotheca acuminate. J. Am. Chem. Soc. 1966, 88, 3888–3890.
(19) Werbovetz, K. A.; Bhattacharjee, A. K.; Brendle, J. J.; Scovill,
J. P. Analysis of stereoelectronic properties of camptothecin analogues in
relation to biological activity. Bioorg. Med. Chem. 2000, 8, 1741–1747.
(20) Bedeschi, A.; Zarini, F.; Cabri, W.; Candiani, I.; Penco, S.;
Capolongo, L.; Ciomei, M.; Farao, M.; Grandi, M. Synthesis and
antitumor activity of a new class of water soluble camptothecin
derivatives. Bioorg. Med. Chem. Lett. 1996, 6, 671–674.
(21) Schmid, B.; Chung, D.-E.; Warnecke, A.; Fichtner, I.; Kratz, F.
Albumin-binding prodrugs of camptothecin and doxorubicin with an
Ala-Leu-Ala-Leu-linker that are cleaved by cathepsin B: synthesis and
antitumor efficacy. Bioconjugate Chem. 2007, 18, 702–716.
(22) Ishii, M.; Iwahana, M.; Mitsui, I.; Minami, M.; Imagawa, S.;
Tohgo, A.; Ejima, A. Growth inhibitory effect of a new camptothecin
analog, DX-8951f, on various drug-resistant sublines including BCRP-
mediated camptothecin derivative-resistant variants derived from the
human lung cancer cell line PC-6. Anti-Cancer Drugs 2000, 11, 353–362.
(36) Tseng, C. H.; Chen, Y. L.; Yang, S. H.; Peng, S. I.; Cheng, C. M.;
Han, C. H.; Lin, S. R.; Tzeng, C. C. Synthesis and antiproliferative
evaluation of certain iminonaphtho[2,3-b]furan derivatives. Bioorg. Med.
Chem. 2010, 18, 5172–5182.
(37) Tuppy, H.; Bohm, F. Synthesis of dictamnine. Monatsh. Chem.
1956, 87, 720–734.
(38) Vougogiannopoulou, K.; Ferandin, Y.; Bettayeb, K.;
Myrianthopoulos, V.; Lozach, O.; Fan, Y.; Johnson, C. H.; Magiatis,
P.; Skaltsounis, A.-L.; Mikros, E.; Meijer, L. Soluble 30,6-substituted
indirubins with enhanced selectivity toward glycogen synthase kinase-3
alter circadian period. J. Med. Chem. 2008, 51, 6421–6431.
(39) Morris, G. M.; Goodsell, D. S.; Halliday, R. S.; Huey, R.; Hart,
W. E.; Belew, R. K.; Olson, A. J. Automated docking using a lamarckian
genetic algorithm and empirical binding free energy function. J. Comput.
Chem. 1998, 19, 1639–1662.
(40) Gigant, B.; Wang, C.; Ravelli, R. B. G.; Roussi, F.; Steinmetz,
M. O.; Curmi, P. A.; Sobel, A.; Knossow, M. Structural basis for the
regulation of tubulin by vinblastine. Nature 2005, 435, 519–522.
4460
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461

Journal of Medicinal Chemistry
ARTICLE
(41) Ravelli, R. B. G.; Gigant, B.; Curmi, P. A.; Jourdain, I.; Lachkar,
S.; Sobel, A.; Knossow, M. Insight into tubulin regulation from a
complex with colchicine and a stathmin-like domain. Nature 2004,
428, 198–202.
(42) Downing, K. H. Structural basis for the interaction of tubulin
with proteins and drugs that affectmicrotubule dynamics. Annu. Rev. Cell
Dev. Biol. 2000, 16, 89–111.
(43) Tsuzuki, S. Interactions with aromatic rings. Struct. Bonding
2005, 115, 149–193.
4461
dx.doi.org/10.1021/jm200046z |J. Med. Chem. 2011, 54, 4446–4461