Synthesis and structure-activity relationship study of 8-hydroxyquinoline- derived Mannich bases as anticancer agents

Article abstract of DOI:10.1016/j.ejmech.2010.03.008

To continue our early study on the structural modifications of clioquinol, more 8-hydroxyquinoline-derived Mannich bases were synthesized and examined for growth-inhibitory effect. Taken Mannich base 1 as our lead compound, upon replacement of either sulfonyl group with methylene group or piperazine ring with ethylenediamine group resulted in an appreciable increase in potency. On the other hand, as 8-hydroxyquinoline was replaced with phenol, 3-hydroxypyridine and 1-naphthol, a dramatic decrease in activity was observed, indicating that 8-hydroxyquinoline is a crucial scaffold for activity. Further 3D-QSAR analysis on HeLa cells revealed that both steric and electronic effects contributed equally to growth inhibition. Taken together, the structure-activity relationships obtained from both in vitro data and CoMFA model warrant a valuable reference for further study.

Full text of DOI:10.1016/j.ejmech.2010.03.008

European Journal of Medicinal Chemistry 45 (2010) 2860e2867
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and structure-activity relationship study of 8-hydroxyquinoline-derived
Mannich bases as anticancer agents
,
e
,
a
a
b
c
b
Arthur Y. Shaw a , Chun-Yi Chang , Mei-Yuan Hsu , Pei-Jung Lu , Chia-Ning Yang , Hui-Ling Chen ,
*
Cheng-Wei Lo c, Chung-Wai Shiau d, Ming-Kai Chern a
a Department of Chemistry, Tamkang University, Danshui 251, Taiwan
b Institute of Clinical Medicine, National Cheng Kung University, Tainan 701, Taiwan
c Institute of Biotechnology, National University of Kaohsiung, Kaohsiung 700, Taiwan
d Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei 112, Taiwan
e Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85724, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
To continue our early study on the structural modifications of clioquinol, more 8-hydroxyquinoline-
derived Mannich bases were synthesized and examined for growth-inhibitory effect. Taken Mannich
base 1 as our lead compound, upon replacement of either sulfonyl group with methylene group or
piperazine ring with ethylenediamine group resulted in an appreciable increase in potency. On the other
hand, as 8-hydroxyquinoline was replaced with phenol, 3-hydroxypyridine and 1-naphthol, a dramatic
decrease in activity was observed, indicating that 8-hydroxyquinoline is a crucial scaffold for activity.
Further 3D-QSAR analysis on HeLa cells revealed that both steric and electronic effects contributed
equally to growth inhibition. Taken together, the structure-activity relationships obtained from both in
vitro data and CoMFA model warrant a valuable reference for further study.
Received 15 October 2009
Received in revised form
4 March 2010
Accepted 9 March 2010
Available online 12 March 2010
Keywords:
Clioquinol
8-Hydroxyquinoline
Mannich-type reaction
Structure-activity relationship
Ó 2010 Elsevier Masson SAS. All rights reserved.
1. Introduction
induced antiproliferative effect is attributed to caspase-dependent
apoptotic pathway. Moreover, antiproliferative effect mediated by
In addition to applications in the design of chemosensors and
optical devices [1e4], 8-hydroxyquinoline has been synthesized
with a variety of biological activities, such as inhibitors of catechol
clioquinol could be enhanced in the presence of metal ions thanks to
its metal-binding property [20,21].
Our early study showed that upon the elongation of 8-hydrox-
yquinoline appended by an arylsulfonylpiperazine moiety (1 and
25, Fig. 1) through Mannich-type reaction resulted in dramatically
improved growth-inhibitory effect. We further demonstrated that
growth inhibition induced by 8-hydroxyquinoline-derived Man-
nich bases was attributed to caspase-dependent apoptotic pathway
and generation of oxygen reactive species. The synergistic effect of
growth inhibition mediated by Mannich bases was also observed in
the presence of copper ion, which was in accordance with that of
clioquinol [22]. Herein, we would like to report the structural
modifications of 8-hydroxyquinoline-derived Mannich bases with
aim to examine their growth-inhibitory effect. Moreover, 3D-QSAR
analysis employed by CoMFA model on HeLa cell line will be pre-
sented in this paper as well.
O-methyltransferase [5], inhibitors of HIF-1a prolyl hydroxylase [6],
inhibitors of HIV-1 integrase [7], antibacterial [8,9], antimalarial
[10], and antitumor agents [11e13]. Similar to carbonyl compounds
with keto-enol tautomerism that enables a multiple-component
Mannich reaction, 8-hydroxyquinoline can be carried out to
generate the corresponding Mannich bases [10,14,15]. As a conse-
quence, several Mannich bases of 8-hydroxyquinoline derivatives
have been synthesized to show several biological activities [16,17].
On the other hand, clioquinol (5-chloro-7-iodo-8-hydoxyquino-
line, Fig. 1) was clinically used as an antibiotic for the treatment of
diarrhea and skin infection. Recently, clioquinol has demonstrated
to exhibit anti-Alzheimer’s disease in a mouse model via the
reduction or prevention of amyloid plaque accumulation in the
brain [18,19]. Apart from its antibiotic and anti-Alzheimer’s disease
efficacies, clioquinol also showed a moderate antiproliferative effect
on cancer cells. The mechanistic study revealed that clioquinol-
2. Chemistry
As shown in Fig. 2, a series of 8-hydroxyquinoline-derived
Mannich bases were prepared in a systematic manner. In Route A,
* Corresponding author. Tel.: þ886 2 2621 5656; fax: þ886 2 2620 9924.
E-mail address: shaw.299@gmail.com (A.Y. Shaw).
0223-5234/$ e see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2010.03.008

A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
2861
planar geometry in aromatic system connected to the sulfonyl
group is favorable for growth-inhibitory activity. On the other hand,
data showed that either electron-donating substituents such as 5
Cl
R'
O O
S
N
(4-CH3, GI50, 2.5
withdrawing substituents like 9 (4-CF3, GI50, 2.2
NO2, GI50, 2.3 M) revealed better activities than the counterpart 1
(GI50, 6.8 M) against HeLa cells. Interestingly, 10 (GI50, 2.4 M)
bearing 3-methoxy group exhibited higher activity than the
counterparts 11 (4-OMe, GI50, 5.0 M), 12 (3, 4-di-OMe, GI50
5.0 M) and 13 (4-OCF3, GI50, 4.3 M) against HeLa cells. Likewise,
the abovementioned structure-activity relationship was also found
in both BT483 and SKHep cells. As shown, 10 (3-OMe, GI50, 4.1 M)
showed 3-fold more potent than 12 (GI50, 17.4 M) against SKHep
cells. In addition, the growth inhibition of mono-substituted
benzene ring in Mannich bases such as 10 (3-OMe, GI50, 7.2 M) and
11 (4-OMe, GI50, 5.2 M) revealed higher activity than the di-
substituted counterpart 12 (3, 4-di-OMe, GI50, 12.1 M) against
m
M) and 10 (3-OMe, GI50, 2.4
mM) or electron-
N
N
I
mM) and 15 (4-
N
R
OH
m
OH
m
m
R = R' = H
R = CH3 , R' = NO2
1
Clioquinol
25
m
,
m
m
Fig. 1. Chemical structures of clioquinol and its Mannich bases 1 and 25.
m
m
we replaced a variety of substituents on benzene ring to obtain
2e17 (Scheme 1, Fig. 3). In Route B, the sulfonyl group was replaced
by either a carbonyl group or a methylene group to generate 18 and
19, respectively (Scheme 2, Fig. 3). In Route C, the piperazine moiety
in 1 was replaced by an ethylenediamine linker to synthesize 20
(Scheme 3, Fig. 3). In Route D, Mannich-type reaction of hydrox-
yarenes such as phenol, 3-hydroxypyridine, 1-naphthol and 5-
subsituted 8-hydroxyquinoline were utilized to afford 21e27
(Scheme 4, Fig. 3, Table 1). Accordingly, a mixture of hydroxyarene,
along with formaldehyde and amine was stirred in ethanol at reflux
for 16e22 h that successfully prepared the corresponding Mannich
bases [10,14,15,22].
m
m
m
CE81T cells. These findings suggest a distinct steric effect stemmed
from the substituted benzene ring that counts for the growth-
inhibitory activity. Nevertheless, the electron-withdrawing
substituent such as 14 and 15 bearing a nitro group on the benzene
ring exhibited a comparable growth-inhibitory activity against all
four cell lines. On the other hand, only SKHep showed a higher
sensitivity in response to halogen-substituted Mannich bases 2 (4-
F, GI50, 4.8
compared to their counterpart 1 (GI50, 14.6
modified in Route A, 13 (4-OCF3) exhibited the most potent growth-
mM), 3 (4-Cl, GI50, 5.0
mM) and 4 (4-Br, GI50, 12.7
mM) as
mM). Among analogs
3. Results and discussion
inhibitory activity with a GI50 value of 2.9
line.
mM against CE81T cell
All tested compounds were screened on a panel of human
carcinoma cell lines for growth-inhibitory activities, including HeLa
(cervical epithelioid carcinoma cell), BT483 (mammary gland
adenocarcinoma cell), SKHep (hepatocellular carcinoma cell) and
CE81T (esophageal carcinoma cell). The MTT (3-[4,5-dimethylth-
iazol-2-yl]-2,5-diphenyltetrazolium bromide) assay [23] was
employed for the growth inhibition studies and the GI50 values are
summarized in Tables 2 and 3. The compound concentration
causing a 50% cell growth inhibition (GI50) was determined by
interpolation from dose-response curves.
As shown in Scheme 2, upon replacement of the sulfonyl group
in 1 with a carbonyl group (18) and a methylene group (19) resulted
in an interesting structure-activity correlation. For example, 19
showed 2- to 10-fold more potent than the counterparts 1 and 18
against four carcinoma cells (Table 3), suggesting the flexibility
originated from the rotational methylene group plays a significant
role for activity. In addition, 19 exhibited higher potency with a GI50
value of 2.6
m
M against SKHep cells while both 1 and 18 merely
M,
showed moderate activities with GI50 values of 14.6 and 26.6
m
respectively. Unlike 19 bearing a methylene group for free rotation,
both 1 (sulfonyl group) and 18 (carbonyl group) are devoid of the
rotation capability for activity. Interestingly, as the piperazine ring
in 1 was replaced with an ethylenediamine group to generate 20, an
improved growth-inhibitory effect was also observed. Together,
these results indicate that the flexible fragments in both 19 and 20
As compared to 1 (phenyl, GI50, 6.8
GI50, 2.5 M), 6 (4-isoprpylphenyl, GI50, 6.1
phenyl, GI50, 4.7 M) and 8 (4-biphenyl, GI50, 4.5
17 bearing 1-naphthyl and 2-naphthyl moieties exhibited higher
growth-inhibitory effect against HeLa cells with GI50 values of 1.8
m
M), 5 (4-methylphenyl,
M), 7 (4-tert-butyl-
M), both 16 and
m
m
m
m
and 1.7 mM, respectively. These results indicate a certain degree of
O
O
S
N
Ar
O
O
H
N
N
S
N
N
N
H
OH
OH
2-17
20
Scheme 1
Scheme 3
C
A
O
O
S
N
B
N
N
Scheme 4
Scheme 2
OH
1
X
N
O
O
D
S
N
N
N
Ar
Ar'
N
OH
X = CO
18
X = CH2 19
21-27
Fig. 2. Overall synthetic routes of structure-activity relationship study of 8-hydroxyquinoline-derived Mannich bases.

2862
A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
Scheme 1
O
O
O
O
S
S
N
Ar
N
Ar
a
HCHO
+
+
N
N
HN
N
OH
O
OH
2a -17a
2 - 17
Scheme 2
O
N
N
N
N
N
N
N
HN
OH
OH
b
18
19
18a
N
HN
Scheme 3
H2N
19a
O
O
b
H
H
N
S
N
N
N
S
H
O
O
OH
20
20a
Scheme 4
O
O
O
N
O
R
S
S
N
c
R
HN
Ar
N
1a, 5a, 15a
21- 27
Fig. 3. Synthetic schemes employed for the structure-activity relationship of 8-hydroxyquinolines.
play an important role for growth-inhibitory activity. Consequently,
4. 3D-QSAR on HeLa cell line
20 showed more potent activity than their counterpart 1 against
both HeLa and SKHep cells with GI50 values of 1.4 and 3.6
respectively.
m
M,
To highlight the structure-activity relationship of growth inhi-
bition between carcinoma cells in response to the Mannich bases,
CoMFA (Comparative Molecular Field Analysis) was performed by
Sybyl 8.1 (Tripos International, 1699 South Hanley Rd., St. Louis,
Missouri, 63 144, USA) to build a 3D-QSAR model. The study of HeLa
cell line was chosen owing to its significant structure-activity
sensitivity toward the tested compounds. The Gasteiger-Huckel
method was employed to assigning charges on the Mannich bases
and to applying 10 000 steps in Powell algorithm for geometry
optimization. A core structure specified in ball and stick was fixed
upon constructing the tested compounds (Fig. 4A). The alignment
of compounds plays an essential role in determining structure-
activity relationship. For the binding site is not available at this
stage, we assumed each compound would adopt a conformation in
its lowest energy. Database alignment protocol in Sybyl 8.1 was
used to align the structures according to the abovementioned core.
To build a CoMFA model, the CoMFA descriptors including steric
(Lennard-Jones 6e12 potential) and electrostatic (Coulombic
potential) field energies were calculated with a sp3 carbon atom
carrying þ1.0 charge to serve as a probe atom using Sybyl default
parameters.
Upon replacement of 8-hydroxyquinoline with phenol,
3-hydroxypyridine, and 1-naphthol (Tables 1 and 3) to obtain the
corresponding Mannich bases 21, 22 and 23, respectively, all of
which exhibited a dramatic loss of activity against screened cell
lines, suggesting that 8-hydroxyquinoline is a critical pharmaco-
phore for growth-inhibitory activity. As regard to the modification
at 5-position on 8-hydroxyquinoline, Mannich bases 24e27 were
synthesized that showed a certain degree of structure-activity
correlation. For example, exposure of both HeLa and BT483 cells to
24 (5-NO2 on 8-hydroxyquinoline) exhibited a 2-fold activity as
compared to the counterpart 1 (Table 3). Further structural modi-
fications of 24 on the benzene to generate both 25 (4-CH3) and 26
(4-NO2) displayed an interesting cell typeeselective activity. As
shown, both 25 and 26 revealed improved growth-inhibitory effect
on HeLa cells in comparison to 24 (GI50, 3.1
0.7 and 1.2 M, respectively. Nevertheless, only 25 exhibited 2-fold
more potency than 24 against BT483 cells with a GI50 value of
1.9 M, representing the most activity among all tested compounds.
mM) with GI50 values of
m
m
Interestingly, among four analogs 24-27, only 27 bearing 5-chloro
group showed 1.6-fold more potent than the parent compound 1
All compounds were included in training set to build a CoMFA
model whose statistical results are listed in Fig. 4B. The optimal
number of components (ONC ¼ 6) was recommended after
a leave-one-out cross-validated run with q2 ¼ 0.396, which is
with a GI50 value of 5.5
mM against SKHep cells, indicating the
preferred sensitivity of individual cell lines in response to the tested
compounds.

A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
2863
Table 1
Table 2
Chemical structures of Mannich bases 21e27.
Growth inhibition of 8-hydroxyquinolines 1-17 against carcinoma cell lines. GI50
values are presented as the mean ꢀ sem (standard error of the mean) from four to
six separated experiments.
Entry
Ar
R
Entry Ar
GI50
(mM)
21
22
H
HeLa
BT483
SKHep
CE81T
1
phenyl
6.8 ꢀ 1.1 10.7 ꢀ 2.6 14.6 ꢀ 3.6 5.6 ꢀ 1.8
4.4 ꢀ 0.7 12.5 ꢀ 2.5 4.5 ꢀ 0.5 7.2 ꢀ 0.7
4.6 ꢀ 0.8 12.1 ꢀ 1.8 5.0 ꢀ 0.6 6.0 ꢀ 0.7
6.8 ꢀ 0.6 9.0 ꢀ 1.7 12.7 ꢀ 1.9 5.9 ꢀ 0.5
2.5 ꢀ 0.2 9.8 ꢀ 1.1 14.3 ꢀ 0.4 4.9 ꢀ 0.9
6.1 ꢀ 0.5 12.2 ꢀ 0.3 13.8 ꢀ 1.5 7.1 ꢀ 1.5
4.7 ꢀ 1.6 11.0 ꢀ 3.2 4.4 ꢀ 0.3 3.3 ꢀ 0.2
4.5 ꢀ 0.9 11.4 ꢀ 3.8 4.8 ꢀ 0.7 7.0 ꢀ 2.3
2.2 ꢀ 0.4 5.6 ꢀ 0.5 12.3 ꢀ 1.4 6.2 ꢀ 0.6
2.4 ꢀ 0.4 6.6 ꢀ 0.5 4.1 ꢀ 1.0 7.2 ꢀ 1.1
5.0 ꢀ 0.6 11.9 ꢀ 2.1 6.8 ꢀ 0.1 5.2 ꢀ 0.1
4.9 ꢀ 0.7 15.5 ꢀ 0.7 17.4 ꢀ 1.0 12.1 ꢀ 3.5
2
4-fluorophenyl
3
4
5
6
7
8
4-chlorophenyl
4-bromophenyl
4-methylphenyl
4-isopropylphenyl
4-tert-butylphenyl
4-biphenyl
H
H
9
4-trofluorophenyl
3-methoxyphenyl
4-methoxyphenyl
3,4-dimethoxyphenyl
10
11
12
13
14
15
16
17
23
24
4-trifluoromethoxyphenyl 4.3 ꢀ 0.1 7.5 ꢀ 0.6 8.1 ꢀ 0.9 2.9 ꢀ 0.4
2-nitrophenyl
4-nitrophenyl
1-naphthyl
3.5 ꢀ 0.8 8.4 ꢀ 0.9 10.4 ꢀ 0.7 4.8 ꢀ 1.7
2.3 ꢀ 0.9 13.7 ꢀ 4.2 12.9 ꢀ 1.4 5.9 ꢀ 2.0
1.8 ꢀ 0.7 7.8 ꢀ 1.6 7.5 ꢀ 1.5 4.9 ꢀ 0.9
1.7 ꢀ 0.7 8.8 ꢀ 1.3 7.8 ꢀ 2.3 6.3 ꢀ 0.4
2-naphthyl
H
-2, -3, and -4 columns in Fig. 4B by randomly deleting three data
point from the training set to generate new models and thus
predict the deleted compounds’ pIC50 values. The test set predic-
tions are given in bold in each Pred-column. Comparing the
training and test set results, we found that the fractions of steric
and electrostatic contributions to each model are similar and
equally important.
CoMFA model presented in Fig. 4A showed all generated fields
mapped onto the structure of 25, the most potent Mannich base in
HeLa cell line analysis. As predicted, most of fields sit around the
benzene ring system adjacent to the sulfonyl group since a number
of modifications are centered in this region. The steric fields on the
left side of Fig. 4A indicate that groups such as methyl, tri-
fluoromethyl, and nitro (in 5, 9, 15, 25, and 26) bounded to the
carbon atom para to the sulfonyl group boost the potency since they
fit the green contour (favor bulk group) and bypass the yellow
contour (disfavor bulk group). On the contrary, larger groups such
as isopropyl and tert-butyl in 6 and 7 would contact the yellow
contour and lower the potency. Moreover, the abovementioned
25
26
27
4-CH3
4-NO2
H
Table 3
Growth inhibition of Mannich Bases 18e27 against carcinoma cell lines. GI50 values
are presented as the mean ꢀ sem (standard error of the mean) from four to six
separated experiments.
Entry
GIa50
HeLa
(mM)
acceptable for a small group. The final training set model and
coefficients such as R2 and F-value were obtained by using the
optimal number of components and all the data points in the
training set. The subsequent non-validation R2 ¼ 0.978 is higher
than the criteria value 0.6 required for a fairly good model for
BT483
SKHep
CE81T
18
19
20
21
22
23
24
25
26
27
5.8 ꢀ 0.2
1.6 ꢀ 0.4
1.4 ꢀ 0.3
ND
23.0 ꢀ 2.2
16.9 ꢀ 3.2
3.13 ꢀ 0.5
0.7 ꢀ 0.3
1.2 ꢀ 0.1
4.2 ꢀ 1.3
6.5 ꢀ 2.0
5.8 ꢀ 1.4
8.1 ꢀ 1.1
ND
26.8 ꢀ 2.6
2.6 ꢀ 0.1
3.6 ꢀ 0.6
ND
ND
ND
15.1 ꢀ 2.8
14.6 ꢀ 0.6
15.3 ꢀ 1.5
5.5 ꢀ 0.6
8.8 ꢀ 2.0
2.8 ꢀ 0.7
6.7 ꢀ 0.1
ND
ND
ND
3.7 ꢀ 1.1
5.9 ꢀ 0.5
2.8 ꢀ 0.4
4.4 ꢀ 1.4
28.5 ꢀ 3.4
more realistic communication that
a weak relationship is
ND
observed. The subsequent non-validation R2 ¼ 0.978 is higher
than the criteria value 0.6 required for a fairly good model. To
further ensure the predictive ability of the CoMFA model built
by the training set, we carried out a series of test modeling Pred-1,
5.7 ꢀ 0.9
1.9 ꢀ 0.1
11.2 ꢀ 1.5
7.1 ꢀ 1.1

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A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
Fig. 4. 3D-QSAR analysis on HeLa cell line. (A) Steric and electrostatic fields generated with the CoMFA model projected on 25: yellow indicates regions where bulky groups
decrease activity (contribution level of 80%) whereas green indicates regions where bulky groups increase activity (contribution level of 20%); red indicates regions where
negatively charged groups increase activity (contribution level of 20%), whereas blue indicates regions where positively charged groups increase activity (contribution level of 80%).
The core used in alignment protocol of Sybyl 8.1 program is specified in ball and stick. (B) Statistics of CoMFA analysis.
nitro and methyl groups are correctly positioned into the red (favor
negative charge) and blue (favor positive charge) contours (data not
shown). On the right side of Fig. 4A, the red contours imply that
a negatively charged nitrogen atom in a fused ring system is
essential to the growth inhibition. This finding explains why 21, 22,
and 23, which are lack of such a property, are ranked the poorest
ones along the HeLa column in Table 3. In addition, 5-nitro group
para to the 8-hydroxyl group within this fused ring system is a plus
contribution as indicated by a small red contour. Accordingly, 25
outperforms 5 and 26 outperforms 15.
5. Conclusion
In summary, a series of 8-hydroxyquinoline-derived Mannich
bases were synthesized and examined for their growth inhibition
with interesting SAR results. The structural modifications reveal
that 8-hydroxyquinol skeleton is required for activity. All Mannich
bases exhibited moderate to low micromolar potency against four
carcinoma cells. In particular, 25 showed the most activities against
both HeLa and BT483 cells with GI50 values of 0.7 and 1.9
respectively, while 19 (GI50, 2.6 and 2.8 M against SKHep and
mM,
m

A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
2865
CE81T cells, respectively) and 26 (GI50, 2.8
m
M against CE81T cells)
6.1.5. 7-((4-Tosylpiperazin-1-yl)methyl)quinolin-8-ol (5)
M.p. 161.6e163.6 ꢁC. 1H NMR (300 MHz, CDCl3)
exhibited the most potent growth-inhibitory effect on SKHep and
CE81T cells. These results suggest the selective sensitivity of indi-
vidual cell lines in response to the tested compounds. Further
CoMFA model of 3D-QSAR analysis provided a q2 value of 0.396 and
revealed that both steric and electronic effects are equally signifi-
cant for activity. Taken together, the structure-activity relationships
received from both in vitro growth inhibition data and CoMFA
model warrant a valuable platform for more detailed study.
d
2.44 (s, 3H),
2.69 (m, 4H), 3.05 (m, 4H), 3.85 (s, 2H), 7.23 (s, 1H), 7.24 (s, 1 H), 7.32
(d, J ¼ 8.2 Hz, 2H), 7.37 (dd, J ¼ 8.4, 4.2 Hz, 1H), 7.61 (d, J ¼ 8.2 Hz,
2H), 8.07 (dd, J ¼ 8.4,1.5 Hz, 1H), 8.80 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm.
13C NMR (75 MHz, CDCl3)
d 21.7, 46.3, 51.9, 59.1, 117.6, 117.8, 121.6,
128.0, 128.3, 128.5, 129.9, 132.1, 135.9, 139.1, 144.1, 148.9, 152.3 ppm.
HRMS (M)þ calcd for C21H23N3O3S 397.1460, found 397.1459. Anal.
Calcd. for C21H23N3O3S: C, 57.48; H, 4.82; N, 10.05. Found: C, 57.20;
H, 4.61; N, 10.26.
6. Experimental protocols
6.1.6. 7-((4-(4-Isopropylphenylsulfonyl)piperazin-1-yl)methyl)
6.1. Synthesis
quinolin-8-ol (6)
M.p. 153.8e155.8 ꢁC. 1H NMR (300 MHz, CDCl3)
d 1.28 (s, 3H),
Chemical reagents and organic solvents were purchased from
Acros, Aldrich and Alfa Aesar unless otherwise mentioned. Melting
points were determined by Fargo MP-2D. Nuclear magnetic reso-
nance spectra (1H and 13C NMR) were measured on a Bruker AC-
1.30 (s, 3H), 2.69 (m, 4H), 2.99 (m, 1H), 3.07 (m, 4H), 3.85 (s, 2H),
7.22 (s, 1H), 7.23 (s, 1H), 7.35 (dd, J ¼ 8.2, 4.2 Hz, 1 H), 7.37 (d,
J ¼ 8.3 Hz, 2H), 7.64 (d, J ¼ 8.3 Hz, 2H), 8.07 (dd, J ¼ 8.2, 1.6 Hz, 1H),
8.80 (dd, J ¼ 4.2, 1.6 Hz, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d 23.8,
300 instrument. Chemical shifts (
d
) are reported in ppm relative to
34.4, 46.3, 52.0, 59.2, 117.6, 117.8, 121.7, 127.4, 128.1, 128.3, 128.5,
132.5, 135.9, 139.1, 149.0, 152.3, 154.7 ppm. HRMS (M)þ calcd for
C23H27N3O3S 425.1773, found 425.1775.
the TMS peak. Mass spectra were obtained by FAB on a Jeol JMS-700
instrument. Flash column chromatography was performed with
silica gel (230e400 mesh). Elemental Analysis was carried out on
a Heraeus VarioEL- III C, H, N analyzer.
6.1.7. 7-((4-(4-Tert-butylphenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (7)
6.1.1. General procedure
M.p. 184.1e186.1 ꢁC. 1H NMR (300 MHz, CDCl3)
d 1.37 (s, 9H),
To a solution of 8-hydroxyquinoline or 1-naphthol (1.05 mmol)
and paraformaldehyde (36 mg, 1.26 mmol) in dry ethanol (8 mL)
was added the appropriate secondary amine (1.26 mmol) at room
temperature. The resulting mixture was heated at reflux for
18e22 h. The solvent was removed in vacuo and the crude product
was purified by flash chromatography and/or recrystallization [15].
2.71 (m, 4H), 3.09 (m, 4H), 3.86 (s, 2H), 7.25 (m, 2H), 7.37 (dd,
J ¼ 8.3, 4.2 Hz, 1H), 7.54 (d, J ¼ 8.6 Hz, 2H), 7.65 (d, J ¼ 8.6 Hz, 2H),
8.08 (dd, J ¼ 8.3, 1.6 Hz, 1H), 8.81 (dd, J ¼ 4.2, 1.6 Hz, 1H) ppm. 13C
NMR (75 MHz, CDCl3) d 31.2, 35.4, 46.2, 52.0, 59.2, 117.6, 117.8, 121.7,
126.3, 127.9, 128.3, 128.5, 132.1, 135.9, 139.1, 148.9, 152.3, 157.0 ppm.
HRMS (M)þ calcd for C24H29N3O3S 439.1930, found 439.1923. Anal.
Calcd. for C24H29N3O3S: C, 61.63; H, 5.76; N, 9.80. Found: C, 61.34; H,
5.75; N, 9.61.
6.1.2. 7-((4-(4-Fluorophenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (2)
M.p. 153.2e155.2 ꢁC. 1H NMR (300 MHz, CDCl3)
d
2.69 (m, 4H),
6.1.8. 7-((4-(Biphenyl-4-ylsulfonyl)piperazin-1-yl)methyl)quinolin-
3.08 (m, 4H), 3.85 (s, 2H), 7.20 (s, 2H), 7.25 (m, 2H), 7.38 (dd, J ¼ 8.4,
8-ol (8)
4.2 Hz, 1H), 7.75 (m, 2H), 8.08 (dd, J ¼ 8.4, 1.7 Hz, 1H), 8.80 (dd,
M.p. 225.6e227.6 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.73 (m, 4H),
J ¼ 4.2, 1.7 Hz, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d
46.2, 51.9, 58.7,
3.14 (m, 4H), 3.87 (s, 2H), 7.25 (s, 1H), 7.26 (s, 1H), 7.37 (dd, J ¼ 8.4,
4.2 Hz, 1H), 7.48 (m, 3H), 7.62 (m, 2H), 7.73 (d, J ¼ 8.4 Hz, 2H), 7.80
(d, J ¼ 8.4 Hz, 2H), 8.08 (dd, J ¼ 8.4, 1.7 Hz, 1H), 8.80 (dd, J ¼ 4.2,
116.5, 116.8, 117.7, 117.8, 121.7, 128.5, 130.6, 130.7, 131.6, 136.0, 139.0,
148.9, 152.0 ppm. HRMS (M)þ calcd for C20H20FN3O3S 401.1209,
found 401.1211.
1.7 Hz, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d 46.3, 52.0, 59.0, 87.2,
117.6, 117.8, 121.7, 127.6, 128.0, 128.5, 128.7, 129.2, 133.7, 135.7, 135.9,
139.0, 139.5, 146.3, 148.9, 152.2 ppm. HRMS (M)þ calcd for
C26H25N3O3S 459.1617, found 459.1620. Anal. Calcd. for
C26H25N3O3S: C, 67.95; H, 5.48; N, 9.14. Found: C, 67.73; H, 5.69; N,
9.41.
6.1.3. 7-((4-(4-Chlorophenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (3)
M.p. 157.3e159.3 ꢁC. 1H NMR (300 MHz, MeOH-d4)
d 2.66 (m,
4H), 3.07 (m, 4H), 3.86 (s, 2H), 7.34 (s, 2H), 7.46 (d, J ¼ 8.2, 4.1 Hz,
1H), 7.64 (d, J ¼ 8.5 Hz, 2H), 7.76 (d, J ¼ 8.5 Hz, 2H), 8.22 (dd, J ¼ 8.2,
1.4 Hz, 1H), 8.76 (dd, J ¼ 4.1, 1.4 Hz, 1H) ppm. 13C NMR (75 MHz,
6.1.9. 7-((4-(4-(Trifluoromethyl)phenylsulfonyl)piperazin-1-yl)
methyl)quinolin-8-ol (9)
CDCl3) d 46.2, 51.9, 58.6, 117.7, 117.8, 121.7, 128.5, 129.3, 129.7, 134.0,
135.7, 136.0, 139.0, 139.9, 148.9, 152.0 ppm. HRMS (M)þ calcd for
C20H20ClN3O3S 417.0914, found 417.0913. Anal. Calcd. for
C20H20ClN3O3S: C, 57.48; H, 4.82; N, 10.05. Found: C, 57.36; H, 4.64;
N, 9.92.
M.p. 168.3e170.3 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.68 (m, 4H),
3.09 (m, 4H), 3.83 (s, 2H), 7.24 (s, 2H), 7.36 (dd, J ¼ 8.4, 4.2 Hz, 1H),
7.79 (d, J ¼ 8.5 Hz, 2H), 7.85 (d, J ¼ 8.5 Hz, 2H), 8.07 (dd, J ¼ 8.4,
1.5 Hz, 1H), 8.78 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR (75 MHz,
CDCl3) d 46.2, 51.9, 58.4, 117.6, 117.8, 121.7, 126.4, 126.4, 126.5, 126.5,
6.1.4. 7-((4-(4-Bromophenylsulfonyl)piperazin-1-yl)methyl)
128.4, 128.6, 135.9, 138.8, 139.1, 148.8, 151.9 ppm. HRMS (M)þ calcd
for C21H20F3N3O3S 451.1177, found 451.1186. Anal. Calcd. for
C21H20F3N3O3S: C, 55.87; H, 4.47; N, 9.31. Found: C, 55.83; H, 4.23;
N, 9.21.
quinolin-8-ol (4)
M.p. 188.7e190.7 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (m, 4H),
3.08 (m, 4H), 3.86 (s, 2H), 7.26 (s, 2H), 7.39 (dd, J ¼ 8.4, 4.2 Hz, 1H),
7.60 (d, J ¼ 8.6 Hz, 2H), 7.68 (d, J ¼ 8.6 Hz, 2H), 8.09 (dd, J ¼ 8.4,
1.5 Hz, 1H), 8.81 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR (75 MHz,
6.1.10. 7-((4-(3-Methoxyphenylsulfonyl)piperazin-1-yl)methyl)
CDCl3)
d
46.2, 51.9, 58.5, 117.7, 117.8, 119.5, 121.7, 128.4, 128.5, 129.4,
quinolin-8-ol (10)
132.6, 134.4, 135.9, 138.9, 148.8, 152.0 ppm. HRMS (M)þ calcd for
C20H20BrN3O3S 461.0409, found 461.0407. Anal. Calcd. for
C20H20BrN3O3S: C, 51.66; H, 4.59; N, 8.69. Found: C, 51.69; H, 4.55;
N, 8.58.
M.p. 122.1e124.1 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.71 (m, 4H),
3.10 (m, 4H), 3.85 (s, 2H), 3.86 (s, 3H),7.15 (m, 1H), 7.24 (m, 1H), 7.30
(m, 2H), 7.37 (dd, J ¼ 8.4, 4.2 Hz, 1H), 7.42 (m, 2H), 8.08 (dd, J ¼ 8.4,
1.5 Hz, 1H), 8.82 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR (75 MHz,

2866
A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
CDCl3)
d
46.2, 51.9, 55.8, 59.0, 112.9, 117.6, 117.8, 119.2, 120.0, 121.6,
ppm. 13C NMR (75 MHz, CDCl3)
d 45.9, 52.2, 58.6, 117.7, 121.6, 124.3,
128.3, 128.4, 130.3, 135.9, 136.3, 139.0, 148.9, 152.2, 160.1 ppm.
125.3, 127.0, 128.3, 128.5, 129.1, 129.2, 130.7, 132.3, 134.5, 134.8,
135.9, 138.9, 148.7, 151.9 ppm. HRMS (Mþ1)þ calcd for C24H24N3O3S
434.1538, found 434.1537.
HRMS (M)þ calcd for C21H23N3O4S 413.1409, found 413.1411.
6.1.11. 7-((4-(4-Methoxyphenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (11)
6.1.17. 7-((4-(Naphthalen-2-ylsulfonyl)piperazin-1-yl)methyl)
M.p. 182.3e184.3 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (brs, 4H),
quinolin-8-ol (17)
M.p. 201.9e203.9 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (t,
3.06 (brs, 4H), 3.86 (s, 2H), 3.89 (s, 3H), 7.00 (d, J ¼ 8.7 Hz, 2H), 7.24
(s, 2H), 7.37 (dd, J ¼ 8.4, 4.2 Hz, 1H), 7.67 (d, J ¼ 8.7 Hz, 2H), 8.08 (dd,
J ¼ 8.4, 1.5 Hz, 1H), 8.81 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR
J ¼ 4.9 Hz, 4H), 3.16 (brs, 4H), 3.84 (s, 2 H), 7.24 (s, 2H), 7.36 (dd,
J ¼ 8.4, 4.2 Hz, 1H), 7.67 (m, 3H), 7.97 (m, 3H), 8.07 (dd, J ¼ 8.4,
1.5 Hz, 1H), 8.32 (m, 1H), 8.78 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR
(75 MHz, CDCl3)
d 46.3, 52.0, 55.9, 59.2, 114.5, 117.6, 117.9, 121.7,
126.7, 128.3, 128.5, 130.1, 135.9, 139.1, 149.0, 152.4, 163.4 ppm. HRMS
(75 MHz, CDCl3)
d 46.3, 51.9, 58.5, 117.7, 121.5, 122.9, 127.7, 128.0,
(Mþ1)þ calcd for C21H24N3O4S 414.1488, found 414.1488.
128.2, 128.4, 129.0, 129.2, 129.3, 129.4, 132.2, 132.4, 135.0, 135.8,
138.8, 148.7, 151.9 ppm. HRMS (M)þ calcd for C24H23N3O3S
433.1460, found 433.1456.
6.1.12. 7-((4-(3,4-Dimethoxyphenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (12)
M.p. 81.5e83.5 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.71 (m, 4H), 3.08
6.1.18. (4-((8-Hydroxyquinolin-7-yl)methyl)piperazin-1-yl)
(m, 4H), 3.86 (s, 2H), 3.92 (s, 3H), 3.97 (s, 3H), 6.97 (d, J ¼ 8.4 Hz,1H),
7.18 (d, J ¼ 2.1 Hz,1H), 7.24 (m, 2H), 7.32 (dd, J ¼ 8.4, 2.1 Hz,1H), 7.37
(dd, J ¼ 8.4, 4.2 Hz,1H), 8.08 (dd, J ¼ 8.4,1.5 Hz,1H), 8.81 (dd, J ¼ 4.2,
(phenyl)methanone (18)
1H NMR (300 MHz, CDCl3)
d 2.47 (m, 4H), 3.77 (m, 4H), 7.20 (m,
2H), 7.27 (m, 6H), 7.30 (dd, J ¼ 8.4, 4.2 Hz, 1H), 8.00 (dd, J ¼ 8.4,
1.5 Hz, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d 46.3, 52.0, 56.4, 59.1,
1.5 Hz, 1H), 8.74 (dd, J ¼ 4.1, 1.5 Hz, 1H) ppm. 13C NMR (75 MHz,
110.4, 110.9, 117.6, 117.9, 121.7, 121.9, 126.8, 128.3, 128.5, 135.9, 139.0,
149.0, 149.3, 152.3, 153.1 ppm. HRMS (M)þ calcd for C22H25N3O5S
443.1515, found 443.1516. Anal. Calcd. for C22H25N3O5S: C, 59.58; H,
5.68; N, 9.47. Found: C, 59.42; H, 5.55; N, 9.27.
CDCl3)
d 47.4, 52.7, 58.5, 117.5, 117.7, 121.3, 126.9, 128.1, 128.3, 129.5,
129.6, 135.4, 135.7, 138.6, 148.4, 151.7, 170.1 ppm. HRMS (M)þ calcd
for C21H21N3O2 347.1634, found 347.1638.
6.1.19. 7-((4-Benzylpiperazin-1-yl)methyl)quinolin-8-ol (19)
6.1.13. 7-((4-(4-(Trifluoromethoxy)phenylsulfonyl)piperazin-1-yl)
methyl)quinolin-8-ol (13)
M.p. 131.7e133.7 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.65 (brs, 4H),
2.76 (brs, 4H), 3.60 (s, 2H), 3.96 (s, 2H), 7.31 (m, 5H), 7.39 (dd,
M.p. 145.6e147.6 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (m, 4H),
J ¼ 8.4, 4.2 Hz, 1H), 8.10 (d, J ¼ 8.4 Hz, 1H), 8.41 (brs, 3H), 8.87 (d,
3.10 (m, 4H), 3.86 (s, 2H), 7.26 (m, 2H), 7.34 (d, J ¼ 6.9 Hz, 2H), 7.36
(dd, J ¼ 8.4, 4.2 Hz, 1H), 7.79 (d, J ¼ 6.9 Hz, 2H), 8.09 (dd, J ¼ 8.4,
1.5 Hz, 1H), 8.81 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR (75 MHz,
J ¼ 4.2 Hz, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d 52.3, 52.4, 59.7,
62.7, 117.4, 117.7, 121.6, 127.6, 128.3, 128.5, 128.7, 129.6, 136.1, 137.0,
139.1, 149.0, 153.1 ppm. HRMS (M)þ calcd for C21H23N3O 333.1841,
found 333.1850.
CDCl3) d 46.2, 52.0, 58.6, 117.7, 117.9, 121.2, 121.8, 128.4, 128.6, 130.1,
134.0, 136.0, 139.0, 148.9, 152.0, 152.7 ppm. HRMS (M)þ calcd for
C21H20F3N3O4S 467.1127, found 467.1130.
6.1.20. N-(2-((8-Hydroxyquinolin-7-yl)methylamino)ethyl)
benzenesulfonamide (20)
6.1.14. 7-((4-(2-Nitrophenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (14)
M.p. 147.6e149.6 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.90 (t,
M.p. 78.6e80.6 ꢁC. 1H NMR (300 MHz, CDCl3)
d
2.70 (t, J ¼ 5.0 Hz,
J ¼ 6.4 Hz, 2H), 3.42 (t, J ¼ 6.4 Hz, 2H), 3.78 (s, 2H), 4.14 (s, 2H), 7.28
(s, 2H), 7.43 (dd, J ¼ 8.1, 4.3 Hz, 1H), 7.53 (d, J ¼ 7.4 Hz, 2H), 7.61 (m,
1H), 7.85 (d, J ¼ 7.4 Hz, 2H), 8.13 (d, J ¼ 8.1, 1H), 8.79 (d, J ¼ 4.3 Hz,
4H), 3.37 (t, J ¼ 5.0 Hz, 4H), 3.88 (s, 2H), 7.29 (m, 2H), 7.40 (dd,
J ¼ 8.4, 4.2 Hz, 1H), 7.61 (m, 1H), 7.70 (m, 2H), 7.92 (m, 1H), 8.10 (dd,
J ¼ 8.4, 1.5 Hz, 1H), 8.82 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR
1H) ppm. 13C NMR (75 MHz, CDCl3)
d 45.7, 52.0, 52.5, 70.3, 117.8,
118.7, 121.9, 127.8, 128.1, 129.0, 129.3, 133.1, 136.1, 137.4, 138.5, 148.5,
150.6 ppm. HRMS (M)þ calcd for C18H19N3O3S 357.1147, found
357.1143. Anal. Calcd. for C18H19N3O3S: C, 60.49; H, 5.36; N, 11.76.
Found: C, 61.57; H, 5.26; N, 11.38.
(75 MHz, CDCl3)
d 46.2, 52.2, 58.7, 117.7, 117.9, 121.7, 124.2, 128.4,
128.6, 130.6, 131.0, 131.6, 134.1, 136.0, 138.9, 148.9, 152.0 ppm. HRMS
(M)þ calcd for C20H20N4O5S 428.1154, found 428.1149. Anal. Calcd.
for C20H20N4O5S: C, 56.06; H, 4.70; N, 13.08. Found: C, 56.09; H,
5.00; N, 13.34.
6.1.21. 2-((4-(Phenylsulfonyl)piperazin-1-yl)methyl)phenol (21)
6.1.15. 7-((4-(4-Nitrophenylsulfonyl)piperazin-1-yl)methyl)
M.p. 151.6e153.6 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.64 (brs, 4H),
quinolin-8-ol (15)
3.09 (brs, 4H), 3.70 (s, 2H), 6.77 (m, 2H), 6.97 (m, 1H), 7.16 (m, 1H),
M.p. 171.8e173.8 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (m, 4H),
7.59 (m, 3H), 7.75 (m, 2H), 10.08 (brs, 1H) ppm. 13C NMR (75 MHz,
3.14 (m, 4H), 3.85 (s, 2H), 7.28 (m, 2H), 7.40 (dd, J ¼ 8.4, 4.2 Hz,
1H), 7.93 (d, J ¼ 8.8 Hz, 2H), 8.10 (dd, J ¼ 8.4, 1.5 Hz, 1H), 8.39 (d,
J ¼ 8.8 Hz, 2H), 8.80 (dd, J ¼ 4.2, 1.5 Hz, 1H) ppm. 13C NMR
CDCl3) d 46.1, 51.8, 61.2, 116.2, 119.7, 120.6, 127.9, 129.1, 129.3, 129.4,
133.4, 135.5, 157.3 ppm. HRMS (M)þ calcd for C17H20N2O3S
332.1195, found 332.1191.
(75 MHz, CDCl3)
d 46.2, 51.9, 58.2, 117.6, 117.8, 121.8, 124.5, 128.3,
128.7, 129.0, 136.0, 138.8, 141.6, 148.8, 150.4, 151.8 ppm. HRMS
(M)þ calcd for C20H20N4O5S 428.1154, found 428.1155. Anal. Calcd.
for C20H20N4O5S: C, 56.06; H, 4.70; N, 13.08. Found: C, 55.89; H,
4.79; N, 13.12.
6.1.22. 2-((4-(Phenylsulfonyl)piperazin-1-yl)methyl)pyridin-3-ol
(22)
M.p. 146.1e148.1 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.71 (brs, 4H),
3.14 (brs, 4H), 3.92 (s, 2H), 7.04 (d, J ¼ 8.2 Hz, 1H), 7.10 (dd, J ¼ 8.2,
6.1 Hz,1H), 7.57 (d, J ¼ 8.7 Hz, 2H), 7.65 (m,1H), 7.76 (dd, J ¼ 8.7, 2H),
6.1.16. 7-((4-(Naphthalen-1-ylsulfonyl)piperazin-1-yl)methyl)
8.03 (d, J ¼ 6.1, 1H) ppm. 13C NMR (75 MHz, CDCl3)
d 45.9, 52.0, 63.4,
quinolin-8-ol (16)
123.1, 124.0, 127.8, 129.4, 133.4, 135.6, 140.6, 141.6, 153.9 ppm. HRMS
(M)þ calcd for C16H19N3O3S 333.1147, found 333.1150. Anal. Calcd.
for C16H19N3O3S: C, 57.64; H, 5.74; N,12.60. Found: C, 57.58; H, 5.79;
N, 12.44.
M.p. 84.2e86.2 ꢁC. 1H NMR (300 MHz, CDCl3)
d
2.65 (t, J ¼ 4.9 Hz,
4H), 3.23 (t, J ¼ 4.9 Hz, 4H), 3.81 (s, 2 H), 7.24 (s, 2H), 7.37 (m, 1H),
7.59 (m, 3H), 7.94 (m, 1H), 8.08 (m, 2H), 8.18 (m, 1H), 8.79 (m, 2H)

A.Y. Shaw et al. / European Journal of Medicinal Chemistry 45 (2010) 2860e2867
2867
6.1.23. 2-((4-(Phenylsulfonyl)piperazin-1-yl)methyl)naphthalen-1-
ol(23)
M.p. 92.0e94.0 ꢁC. 1H NMR (300 MHz, CDCl3)
5% CO2 in a humid atmosphere) 100
m
L of MTT (2 mg/mL in PBS) was
added to each well and the plate was incubated for a further 2 h
d
2.71 (brs, 4H),
(37 ꢁC). The resulting formazan was dissolved in 100
mL DMSO and
3.11 (brs, 4H), 3.85 (s, 2H), 7.05 (d, J ¼ 8.4 Hz, 1H), 7.29 (d, J ¼ 8.4 Hz,
1H), 7.43 (m, 2H), 7.57 (d, J ¼ 7.9 Hz, 2H), 7.65 (d, J ¼ 6.9 Hz,1H), 7.75
(d, J ¼ 7.9 Hz, 2 H), 7.77 (m, 1H), 8.11 (t, J ¼ 6.9 Hz, 1H) ppm. 13C NMR
read at 570 nm. The percentage of growth inhibition was calculated
by the following equation: percentage growth inhibition ¼ (1 -At/
Ac) ꢂ 100, where At and Ac represent the absorbance in treated and
control cultures, respectively. The drug concentration causing a 50%
cell growth inhibition (GI50) was determined by interpolation from
dose-response curves. All determinations were carried out in four to
six separated experiments.
(75 MHz, CDCl3)
d 46.1, 51.9, 61.3, 113.0, 119.0, 122.4, 125.1, 126.4,
126.7, 127.6, 127.7, 127.9, 129.5, 133.4, 134.2, 135.7, 153.0 ppm. HRMS
(M)þ calcd for C21H22N2O3S 382.1351, found 382.1350.
6.1.24. 5-Nitro-7-((4-(Phenylsulfonyl)piperazin-1-yl)methyl)
quinolin-8-ol (24)
6.4. Statistical analysis
M.p.132.7e134.7ꢁC.1HNMR(300 MHz, CDCl3)
d
2.73 (t, J¼ 4.8Hz,
4H), 3.11 (t, J ¼ 4.8 Hz, 4H), 3.89 (s, 2H), 7.55 (m,1H), 7.57 (d, J ¼ 7.2 Hz,
2H), 7.63 (dd, J ¼ 8.8, 3.1 Hz,1 H), 7.67 (m,1H), 7.75 (d, J ¼ 7.2 Hz, 2H),
8.46 (s, 1H), 8.91 (d, J ¼ 3.1 Hz, 1H), 9.26 (d, J ¼ 8.8 Hz, 1H) ppm. 13C
Data are presented as the mean ꢀ sem (standard error of the
mean) from four to six separated experiments. Statistical analyses
were performed using Bonferroni t-test method after ANOVA for
multigroup comparison and Student’s t-test method for two-group
comparison. P ¼ 0.05 was considered significant. Analysis of linear
regression (at least five data within 20e80% inhibition) was used to
calculate GI50 value.
NMR (75 MHz, CDCl3) d 46.1, 52.1, 57.3,116.7,122.3,125.0,127.9,129.2,
129.4, 133.4, 135.4, 135.7, 136.0, 137.8, 149.6, 158.3 ppm. HRMS
(Mþ1)þ calcd for C20H21N4O5S 429.1233, found 429.1239.
6.1.25. 5-Nitro-7-((4-(4-Nitrophenylsulfonyl)piperazin-1-yl)
methyl)quinolin-8-ol (26)
Acknowledgments
M.p. 224.6e226.6 ꢁC. 1H NMR (300 MHz, d6-DMSO)
d 2.48 (brs,
4H), 2.90 (brs, 4H), 3.62 (s, 2H), 7.45 (m, 1H), 7.96 (d, J ¼ 8.5 Hz, 2H),
Financial support from the National Science Council of the
Republic of China and Tamkang University to A. Y. Shaw is gratefully
acknowledged.
8.13 (m, 1H), 8.43 (d, J ¼ 8.5 Hz, 2H), 8.50 (s, 1H), 9.26 (m, 1H) ppm.
13C NMR (75 MHz, d6-DMSO)
d 46.0, 51.6, 55.2, 119.6, 124.2, 124.8,
125.1, 129.2, 133.6, 134.5, 139.8, 140.7, 145.1, 150.2, 172.7 ppm. HRMS
(Mþ1)þ calcd for C20H19N5O7S 473.1005, found 473.1004.
References
6.1.26. 5-Chloro-7-((4-(Phenylsulfonyl)piperazin-1-yl)methyl)
[1] K.C. Song, J.S. Kim, S.M. Park, K.-C. Chung, S. Ahn, S.-K. Chang, Org. Lett. 8 (16)
(2006) 3413e3416.
[2] H. Zhang, L.-F. Han, K.A. Zachariasse, Y.-B. Jiang, Org. Lett. 7 (19) (2005)
4217e4220.
[3] N.M. Shavaleev, R. Scopelliti, F. Gumy, J.-C.G. Bünzli, Inorg. Chem. 47 (19)
(2008) 9055e9068.
[4] T.-T. Wang, G.-C. Zeng, H.-P. Zeng, P.-Y. Liu, R.-X. Wang, Z.-J. Zhang, Y.-L. Xiong,
Tetrahedron 65 (32) (2009) 6325e6329.
[5] R.T. Borchardt, D.R. Thakker, J. Med. Chem. 19 (1976) 558e560.
[6] S.A. Saeed, R.U. Simjee, A.H. Gilani, S. Siddiqui, R. Saleem, S. Faizi, B. Siddiqui,
S. Farnaz, Biochem. Soc. Trans. 20 (4) (1992) 357S.
[7] L. Zhuang, J.S. Wai, M.W. Embrey, T.E. Fisher, M.S. Egbertson, L.S. Payne, J.
P. Guare Jr., J.P. Vacca, D.J. Hazuda, P.J. Felock, A.L. Wolfe, K.A. Stillmock, M.
V. Witmer, G. Moyer, W.A. Schleif, L.J. Gabryelski, Y.M. Leonard, J.J. Lynch Jr., S.
R. Michelson, S.D. Young, J. Med. Chem. 46 (4) (2003) 453e456.
[8] I. Szabo, Nature 212 (5068) (1966) 1384e1385.
[9] H. Gershon, R. Parmegiani, Appl. Microbiol. 10 (1962) 348e353.
[10] N.A. Negm, S.M.I.Morsy, M.M. Said, Bioorg. Med.Chem.13(21)(2005)5921e5926.
[11] L.W. Scheibel, A. Adler, Mol. Pharmacol. 18 (2) (1980) 320e325.
[12] M. Yamato, K. Hashigaki, Y. Yasumoto, J. Sakai, S. Tsukagoshi, T. Tashiro,
T. Tsuruo, Chem. Pharm. Bull. 34 (8) (1986) 3496e3498.
[13] V. Moret, Y. Laras, T. Cresteil, G. Aubert, D.Q. Ping, C. Di, M. Barthélémy-Requin,
C. Béclin, V. Peyrot, D. Allegro, A. Rolland, F. De Angelis, E. Gatti, P. Pierre,
L. Pasquini, E. Petrucci, U. Testa, J.-L. Kraus, Eur. J. Med. Chem. 44 (2) (2009)
558e567.
quinolin-8-ol (27)
M.p. 155.2e157.2 ꢁC. 1H NMR (300 MHz, CDCl3)
d 2.70 (t,
J ¼ 4.8 Hz, 4H), 3.09 (t, J ¼ 4.8 Hz, 4H), 3.82 (s, 2H), 7.36 (s, 1H), 7.49
(m, 1H), 7.56 (d, J ¼ 7.1 Hz, 2H), 7.62 (dd, J ¼ 8.5, 4.2 Hz, 1H), 7.74 (d,
J ¼ 7.1 Hz, 2H), 8.46 (d, J ¼ 8.5 Hz, 1H), 8.85 (d, J ¼ 4.2 Hz, 1H) ppm.
13C NMR (75 MHz, CDCl3)
d 46.2, 52.1, 58.3, 118.1, 120.5, 122.5, 126.1,
128.0, 129.4, 133.2, 133.3, 135.3, 139.4, 149.4, 151.3 ppm. HRMS
(Mþ1)þ calcd for C20H21ClN3O3S 418.0992, found 418.0999.
6.2. Cell culture
Cancer cells were purchased from Bioresource Collection and
Research Center in Taiwan. Each cell line was maintained in the
standard medium and grown as a monolayer in Dulbecco’s Modi-
fied Eagle Medium (DMEM) containing 10% fetal bovine serum,
2 mM glutamine, 100 units/ml penicillin, and 100 g/mL strepto-
mycin. Cultures were maintained at 37 ꢁC with 5% CO2 in
a humidified atmosphere.
[14] R.L. Shriner, G.F. Grillot, W.O. Teeters, J. Am. Chem. Soc. 68 (1946) 946e947.
[15] J.H. Burckhalter, R.I. Leib, J. Org. Chem. 26 (1961) 4078e4083.
[16] M. Medic-Saric, D. Maysinger, M. Movrin, I. Dvorzak, Chemotherapy 26 (4)
(1980) 263e267.
[17] B. Murugasu-Oei, T. Dick, Int. J. Antimicrob. Agents 18 (6) (2001) 579e582.
[18] R.A. Cherny, C.S. Atwood, M.E. Xilinas, D.N. Gray, W.D. Jones, C.A. McLean, K.
J. Barnham, I. Volitakis, F.W. Fraser, Y. Kim, X. Huang, L.E. Goldstein, R.D. Moir, J.
T. Lim, K. Beyreuther, H. Zheng, R.E. Tanzi, C.L. Masters, A.I. Bush, Neuron 30
(2001) 665e676.
[19] C.W. Ritchie, A.I. Bush, A. Mackinnon, S. Macfarlane, M. Mastwyk,
L. MacGregor, L. Kiers, R. Cherny, Q.X. Li, A. Tammer, D. Carrington, C. Mavros,
I. Volitakis, M. Xilinas, D. Ames, S. Davis, K. Beyreuther, R.E. Tanzi, C.L. Masters,
Arch. Neurol. 60 (12) (2003) 1685e1691.
[20] W.-Q. Ding, B. Liu, J.L. Vaught, H. Yamauchi, S.E. Lind, Cancer Res. 65 (8) (2005)
3389e3395.
6.3. MTT assay for cell viability
Cells were plated in 96-well microtiter plates at a density of 5
x103/well and incubated for 24 h. After that, cells were treated with
vehicle alone (control) or compounds (drugs were dissolved in
DMSO previously) at the concentrations indicated. Treated cells
were further incubated for 48 h. Cell survival is expressed as
percentage of control cell growth. The 3-[4, 5-Dimethylthiazol-2-
yl]-2, 5-diphenyltetrazolium bromide (MTT, 2 mg/mL) dye reduction
assay in 96-well microplates was used. The assay is dependent on
the reduction of MTT by mitochondrial dehydrogenases of viable cell
to a blue formazan product, which come be measured spectropho-
tometrically. Tumor cells were incubated in each well with serial
dilutions of the tested compounds. After 2 days of incubation (37 ꢁC,
[21] W.-Q. Ding, H.-J. Yu, S.E. Lind, Cancer Lett. 271 (2008) 251e259.
[22] H.-L. Chen, C.-Y. Chang, H.-T. Lee, H.-H. Lin, P.-J. Lu, C.-N. Yang, C.-W. Shiau, A.
Y. Shaw, Bioorg. Med. Chem. 17 (20) (2009) 7239e7247.
[23] T. Mosman, J. Immunol, Methods 65 (1e2) (1983) 55e63.