Synthesis and in vitro anticancer screening of some novel 4-[2-amino-3-cyano-4-substituted-5,6,7,8-tetrahydroquinolin-1-(4H)-yl] benzenesulfonamides

Article abstract of DOI:10.1016/j.ejmech.2010.03.030

It has been reported that aryl/heteroaryl sulfonamide compounds may act as anticancer agents through a variety of mechanisms and the most prominent of these mechanisms is through the inhibition of carbonic anhydrase isozymes. The present work reports the possible utility of 4-(cyclohexenylamino) benzenesulfonamide in the synthesis of some novel 4-(quinolin-1-yl) benzenesulfonamide derivatives 6aeu. The structures of these compounds were confirmed by elemental analyses, IR, 1H NMR and mass spectral data. All the newly synthesized compounds were evaluated for their in vitro anticancer activity. Some compounds showed interesting in vitro anticancer activities when compared with doxorubicin as a reference drug. In addition, docking of the synthesized compounds into carbonic anhydrase isozyme II (CA II) active site was performed in order to give a suggestion about the proposed mechanism of action.

Full text of DOI:10.1016/j.ejmech.2010.03.030

European Journal of Medicinal Chemistry 45 (2010) 3011e3018
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and in vitro anticancer screening of some novel
4-[2-amino-3-cyano-4-substituted-5,6,7,8-tetrahydroquinolin-1-(4H)-yl]
benzenesulfonamides
,
b
c
d
Mansour S. Al-Said a, Mostafa M. Ghorab a , Saleh I. Al-qasoumi , Ebaa M. El-Hossary , Eman Noaman
*
a Medicinal, Aromatic and Poisonous Plants Research Center (MAPPRC), College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia
b Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
c Department of Drug Radiation Research, National Centre for Radiation Research and Technology, Atomic Energy Authority, Cairo, Egypt
d Department of Radiation Biology, National Centre for Radiation Research and Technology, Atomic Energy Authority, Nasr City, Cairo, Egypt
a r t i c l e i n f o
a b s t r a c t
Article history:
It has been reported that aryl/heteroaryl sulfonamide compounds may act as anticancer agents through
a variety of mechanisms and the most prominent of these mechanisms is through the inhibition of
carbonic anhydrase isozymes. The present work reports the possible utility of 4-(cyclohexenylamino)
benzenesulfonamide in the synthesis of some novel 4-(quinolin-1-yl)benzenesulfonamide derivatives
6aeu. The structures of these compounds were confirmed by elemental analyses, IR, 1H NMR and mass
spectral data. All the newly synthesized compounds were evaluated for their in vitro anticancer activity.
Some compounds showed interesting in vitro anticancer activities when compared with doxorubicin as
a reference drug. In addition, docking of the synthesized compounds into carbonic anhydrase isozyme II
(CA II) active site was performed in order to give a suggestion about the proposed mechanism of action.
Ó 2010 Elsevier Masson SAS. All rights reserved.
Received 18 November 2009
Received in revised form
1 February 2010
Accepted 19 March 2010
Available online 31 March 2010
Keywords:
Synthesis, quinoline
Sulfonamide
Carbonic anhydrase II
Anticancer activity
1. Introduction
these facts, and as a continuation of our work, the present work
reports the possible utility of 4-(cyclohexenylamino)-benzene-
Sulfonamides posses many types of biological activities and
representatives of this class of pharmacological agents are widely
used in clinic as antibacterial [1], hypoglycemic [2], diuretic [3,4],
anti-carbonic anhydrase [3,5] and antithyroid activity [6] among
others. Recently, a host of structurally novel sulfonamide deriva-
tives have been reported to show substantial antitumor activity in
vitro and/or in vivo [7e11].
sulfonamide in the synthesis of some novel 4-(quinolin-1-yl)-
benzenesulfonamide derivatives, in order to study their structure
activity relationship and hoping that the new compounds might
show significant anticancer activity.
2. Results and discussion
From literature survey, it was found that aryl/heteroaryl
sulfonamides may act as antitumor agents through a variety of
mechanisms such as cell cycle perturbation in the G1 phase,
disruption of microtubule assembly, angiogenesis inhibition, and
functional suppression of the transcriptional activator nuclear
factor Y (NF-Y). Moreover, following an extensive evaluation,
numerous sulfonamides were found to act as carbonic anhydrase
(CA) inhibitors [12e17]. The most prominent mechanism was the
inhibition of carbonic anhydrase isozymes (CA) [18].
A general pharmacophore (Fig. 1) for the compounds acting as
carbonic anhydrase inhibitors has been reported by Thiry et al. [22]
from the analysis of the CA active site and from the structure of
inhibitors described in the literature [15].
This pharmacophore includes the structural elements that are
required to be present in the compounds in order to act as CA
inhibitors. This includes the presence of a sulfonamide moiety
which coordinates with the zinc ion of the active site of the CA and
the sulfonamide is attached to a scaffold which is usually a benzene
ring. The side chain might posses a hydrophilic link able to interact
with the hydrophilic part of the active site and a hydrophobic
moiety which can interact with the hydrophobic part of the CA
active site. Fig. 2 includes a representative example of the synthe-
sized compounds showing compliance to the above-mentioned
Also, quinoline derivatives are important biologically active
compounds showing anticancer activity [19e21]. In the light of
* Corresponding author. Tel.: þ966 534292860; fax: þ966 (01) 4670560.
E-mail address: mmsghorab@yahoo.com (M.M. Ghorab).
0223-5234/$ e see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2010.03.030

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M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
of the appropriate aldehyde with malononitrile affording the acti-
viated arylidenemalononitriles 4aeu, followed by addition of
Pro
Val
Leu
Phe
compound
3 to arylidenemalononitrile 4aeu. IR spectra of
compounds 6aeu exhibited bands at 3478e3200 cmꢀ1 due to
(NH2), 2228e2162 cmꢀ1 (ChN), 1397e1134 cmꢀ1 (SO2).
Thr
N
Hydrophobic
moiety
Glu
O
S
2.2. In vitro anticancer screening
Scaffold
Doxorubicin (CAS-23214e92e8), the reference drug used in this
study, is one of the most effective antitumor agents used to produce
regressions in acute leukemias, Hodgkin’s desease and other
lymphomas. The relationship between survival ratio and
compound concentration was plotted to obtain the survival curve
of Ehrlich Ascites Carcinoma (EAC) cells. The response parameter
calculated was IC50 value (Table 1), which corresponds to the
compound concentration causing 50% mortality in net cells.
The parent target molecule, having both hydroquinoline and
sulfonamide moieties, was synthesized with free amino group at
2-position, cyano group at 3-position in addition to several substitu-
ents at 4-position, in order to study the structure activity relationship
of the newly synthesized compounds 6aeu. From the obtained
results, it was found that quinoline derivative 6h carrying benzo[d]
H
Hydrophilic
link
O
Glu
Zn
His
His
His
Gln
Asn
Fig. 1. Structural elements of CA inhibitors in the CA enzymatic active site.
pharmacophore and the compounds were synthesized according to
Scheme 1.
2.1. Chemistry
[1,3]dioxol at 4-position with (IC50 value < 22.2
derivative 6g having 4-methoxyphenyl at 4-position with
(IC50 value ¼ 22.9 M)andquinolinederivative6ehavingstyrylgroup
at 4-position with (IC50 value ¼ 23.1 M) showed higher significant
cytotoxic activity which was even higher activity than that of the
reference drug doxorubicin with (IC50 value ¼ 69.9 M). On the other
hand, compound 6b bearing 4-methylphenyl at 4-position with (IC50
value ¼ 85.7 M) and compound 6d having 4-hydrxyphenyl at
M) are nearly as active as doxo-
mM), quinoline
The compounds were designed with the aim of exploring their
antitumor activity. Thus, the present work reports the possible
m
utility of 4-(cyclohexenylamino)benzenesulfonamide
3 in the
m
synthesis of 4-(2-amino-3-cyano-4-substituted-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl)benzenesulfonamide 6aeu. Compound 3 was
obtained via condensation of cyclohexanone 1 with sulfanilamide 2
in ethanol.
m
m
The structure of compound 3 was proved by elemental analysis,
and spectral data. IR spectrum of 3 revealed the presence of bands
for NH, NH2 at 3380, 3340, 3210 cmꢀ1 (SO2), at 1379, 1186 cmꢀ1. 1H
NMR spectrum of 3 (in DMSO-d6) indicated the presence of a singlet
at 7.8 ppm which could be assigned to NH of the compound 3. The
corresponding quinoline derivatives 6aeu were obtained via
treatment of compound 3 with arylidenemalononitriles 4aeu in
ethanol containing triethylamine as catalyst. The formation of
6aeu was proceed via the formation of intermediate Michael type
products 5aeu, followed by interamolecular cyclization (Scheme
1).
The N-aryl-substituted benzenesulfonamide decreases the
nucleophilicity of the compound 3 towards arylidinemalononitriles
4aeu. The base catalyst triethylamine was required to generate the
anion of compound 3, thus, facilitating the addition to the unsat-
urated nitriles 4aeu (Scheme 2).
4-position with (IC50 value ¼ 82.9
m
rubicinaspositivecontrol.Also, compounds6c, 6f, 6l and 6pexhibited
moderate cytotoxic activities, while compounds 6a, 6iek, 6m-o and
6qeu showed no activity.
2.3. Docking studies
Previous literature shows that carbonic anhydrase inhibition is
one of the anticancer mechanisms of sulfonamides, and this was
clearly reported by Abbate et al. [7], who stated that the potent
anticancer sulfonamide drug (E7070), currently undergoing clinical
development for the treatment of several types of cancer, also acts
as a strong carbonic anhydrase inhibitor, and this may contribute at
least in part, to its in vivo efficacy (Fig. 3).
The X-ray crystal structure of the adduct of human carbonic
anydrase II (hCA II) with E7070 revealed similar interactions
between the inhibitor and the active site as those reported by
Supuran et al. [14,22]. These interactions are found to be common
for the sulfonamide compounds which are CA inhibitors and
include: (i) binding of the compounds to the Zn(II) ion by the
sulfonamide moiety in a tetrahedral geometry which is a stable
geometry for the metal ion. (ii) the nitrogen atom of the sulfon-
amide is coordinated to the Zn(II) ion of the enzyme. (iii) the amino
acid Thr 199 is participates in two hydrogen bonds, one with the NH
moiety and the other with one of the oxygen atoms of the SO2NH2
(Fig. 4) [14,23]
Since, the synthesized compounds are sulfonamide derivatives
and their design complies with the general pharmacophore of
sulfonamide CA inhibitors,, it was interesting to perform docking
studies on the synthesized compounds to hCA II and to compare
their docking interactions with the previously reported interactions
of E7070.
Compounds 6aeu were unambiguously synthesized by another
route involving one-pot condensation of the aldehyde, malononi-
trile and compound 3, in a molar ratio of (1:1:1), in refluxing
ethanol containing triethylamine as catalyst. In this case, formation
of compounds 6aeu are illustrated in terms of initial condensation
Scaffold
O
S
O
Hydrophobic
moiety
N
H2N
H2N
CN
Sulfonamide
Hydrophilic link
In order to validate our docking procedure, E7070 was docked
into the active site of hCA II. The docking results clearly show that
Fig. 2. Representative example of the synthesized compounds showing compliance to
the general pharmacophore of sulfonamide compounds acting as CA inhibitors.

M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
3013
NH2
SO2NH2
EtOH
CN
CN
N
H
O
SO2NH2
EtOH
TEA
Ar
(3)
(1)
(2)
(4a-u)
CN
CN
ArCHO
Ar
Ar
Ar
CN
N
CN
CN
NH
C
NH
N
NH2
N
SO2NH2
SO2NH2
SO2NH2
(5a-u)
(6a-u)
a, Ar = C6H5
l, Ar = C6H3Cl2-2,4
m, Ar = C6H3Cl2-3,4
n, Ar = C6H3OCH3-3,OH-4
o, Ar = C6H3OC2H5-3,OCH3-4
p, Ar = C6H2(OCH3)3-2,4,5
q, Ar = C10H6OH-2
r, Ar = C10H6OCH3-2
s, Ar = C10H6OCH3-4
t, Ar = 5-CH3-2-furyl
u, Ar = 2-thienyl
b, Ar = C6H4CH3-4
c, Ar = C6H4OH-2
d, Ar = C6H4OH-4
e, Ar = C6H5CH=CH
f, Ar = C6H5OCH3-2
g, Ar = C6H4OCH3-4
h, Ar = (benzo[d][1,3]dioxol-5-yl)
i, Ar =C6H4NO2-3
j, Ar = C6H4NO2-4
k, Ar = C6H4Cl-2
Scheme 1.
indeed, the compound exhibits similar interactions as those
previously reported in the literature and stated above (Fig. 5).
Docking of all the synthesized compounds was performed and it
was found that the compounds exhibit similar interactions to that
previously reported for E7070 and stated above. Fig. 6 shows an
example of the interaction map of tetrahydroquinoline derivative
6h docked pose with nearby binding site amino acids of hCA II.
To give a clearer comparison of the docked pose of E7070 and
the most active compound 6h. Fig. 7 shows a three-dimensional
superimposition of docked poses of compound 6h and E7070. It
was found that the benzenesulfonamide moieties bound to hCA II
overlap each other completely while the tail adopts a slightly
different conformation.
cytotoxic activity in vitro against EAC cells, specially compounds 6h,
6g and 6e containing benzo[d][1,3]dioxol, 4-methoxyphenyl and
styryl moieties at 4-position. On the other hand, compounds 6b and
6d are nearly as active as doxorubicin. Docking of the synthesized
compounds in the carbonic anhydrase active site may give
a suggestion that the synthesized compounds may act as carbonic
anhydrase inhibitors and this may contribute in part to their anti-
cancer activity.
4. Experimental
4.1. Chemistry
Finally, it can be seen from our docking study that the synthe-
sized compounds exhibit similar conformations and binding
interactions with hCA II similar to those previously reported for
other sulfonamide compounds that act as CA inhibitors. This
suggests that synthesized compounds might possibly act as CA
inhibitors, and this may contribute at least in part, to the anticancer
activity.
Melting points (ꢁC, uncorrected) were determined in open
capillaries on a Gallenkemp melting point apparatus (Sanyo Gal-
lenkemp, Southborough, UK). Precoated silica gel plates (silica gel
0.25 mm, 60 G F 254; Merck, Germany) were used for thin layer
chromatography, dichloromethane/methanol (9.5:0.5 ml) mixture
was used as a developing solvent system at room temperature and
the spots were visualized by ultraviolet light and/or iodine. Infrared
spectra were recorded in KBr discs using IR-470 Shimadzu spec-
trometer (Shimadzu, Tokyo, Japan). 1H NMR spectra (in DMSO-d6)
were recorded on Bruker Ac-300 ultra shield NMR spectrometer
3. Conclusion
The present work showed that compounds combining hydro-
quinoline and free sulfonamide moieties revealed promising
(Bruker, Flawil, Switzerland,
internal standard. Electron impact Mass Spectra were recorded on
d ppm) at 300 MHz, using TMS as

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M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
Ar
H
CN
N
Ar
CN
C
CN
B
N
N
NH
(4a-u)
-HB
SO2NH2
SO2NH2
SO2NH2
(5a-u)
(3)
HB
-
B
Ar
Ar
H
H
CN
NH
CN
NH2
N
N
SO2NH2
SO2NH2
(6a-u)
Scheme 2. Postulated mechanism for the formation of compounds (6aeu)
a, Shimadzu Gc-Ms-Qp 5000 instrument (Shimadzu, Tokyo, Japan).
Elemental analyses were performed on Carlo Erba 1108 Elemental
Analyzer (Heraeus, Hanau, Germany). All compounds were within
ꢂ0.4% of the theoretical values.
4.1.1. 4-(Cyclohexenylamino)benzenesulfonamide, 3
A mixture of cyclohexanone 1 (0.98 g, 0.01 mol) and sulfanil-
amide 2 (1.72 g, 0.01 mol) in ethanol (30 ml) was refluxed for 5 h.
The reaction mixture was cooled and poured onto ice-cold water.
The obtained solid was crystallized from ethanol to give 3. Yield
79%; mp 129e131 ꢁC. IR (KBr, cmꢀ1): 3380, 3340, 3210 (NH, NH2),
3100 (CH arom.), 2940, 2836 (CH aliph.), 1379, 1186 (SO2). 1H NMR
Table 1
in (DMSO-d6)
d: 1.0e1.4 [m, 8H, 4CH2 cyclo], 4.6 [s, 1H, CH],
In vitro cytotoxic activity of the newly synthesized compounds 6aeu.
6.9e8.0 [m, 7H, AreH þ SO2NH2 þ NH]. Anal. Calcd. For
C12H18N2O2S: C, 56.67; H, 7.13; N, 11.01. Found: C, 56.31; H, 7.00; N,
11.32.
a
Compound No.
Non-viable cells (%)
Concentration ( g/ml)
25
10
IC50
(
m
g/ml)
IC50 (mM)
m
100
50
20
10
4.1.2. 4-[2-Amino-3-cyano-4-substituted-5,6,7,8-
6a
6b
6c
6d
6e
6f
6g
6h
6i
6j
6k
6l
6m
6n
6o
6p
30
90
5
>100b
36
50
35
10
e
tetrahydroquinolin-1(4H)-yl]benzenesulfonamides, 6aeu
Method (A): a mixture of 3 (2.52 g, 0.01 mol) and arylidenema-
lononitriles 4aeu (0.01 mol) in ethanol (30 ml) containing 3 drops
of triethylamine was refluxed for 5 h. The reaction mixture was
filtered while hot and the obtained solid was recrystallized from
ethanol to give 6aeu.
80
50
60
90
50
100
100
2
30
40
42
70
40
90
100
1
20
10
20
50
30
50
100
0
85.7
118.4
82.9
23.1
114.6
22.9
<22.2
e
100
100
70
100
100
100
12
50
10
<10
>100b
>100b
>100b
50
20
10
10
5
5
0
0
0
0
1
e
e
Cl
70
50
50
10
50
50
30
5
50
40
2
105.2
e
100
0
100
e
5
0
>100b
50
e
N
H
100
50
50
20
30
50
20
10
10
10
10
70
0
5
10
5
10
5
0
100.8
e
NH
6q
6r
6s
6t
10
5
0
100
100
e
O
S O
>100b
>100b
>100b
38
e
0
0
e
6u
20
100
e
Doxorubicin
25
17
69.9
a
SO2NH2
IC50 value: corresponds to the compound concentration causing 50% mortality
in net cells.
b
Compounds with IC50 ꢃ 100
mg/ml are considered to be inactive.
Fig. 3. E7070, a sulfonamide compound in advanced clinical trials as anticancer agent.

M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
3015
Hydrophobic part
of active site
Hydrophilic part
of active site
R
O
S
N
H
O
HN
Thr 199
2
Zn
O
H
His 119
His 94
His 96
O
O
Tetrahedral adduct
(sulfonamide)
Glu 106
Fig. 4. CA inhibition mechanism by sulfonamides.
Method (B): a mixture of 3 (2.52 g, 0.01 mol), malononitrile
(0.66 g, 0.01 mol) and aldehyde (0.01 mol) in ethanol (20 ml) con-
taining 3 drops of triethylamine was refluxed for 5 h. The reaction
mixture was filtered while hot and the obtained solid was recrys-
tallized from ethanol to give 6aeu (m.p. and mixed m.p) and the
same Rf.
4.1.2.1. 4-[2-Amino-3-cyano-4-phenyl-5,6,7,8-tetrahydroquinolin-1
(4H)-yl]benzenesulfonamide, 6a. Yield 86%; mp 159e161 ꢁC; IR
(KBr, cmꢀ1): 3477, 3377, 3320, 3244 (2NH2), 2224 (ChN), 1311, 1186
(SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.3 [s, 1H,
CH], 5.7 [s, 2H, NH2], 7.0e7.8 [m, 11H, AreH þ SO2NH2]. Anal. Calcd.
For C22H22N4O2S: C, 65.00; H, 5.46; N, 13.78. Found: C, 65.22; H,
5.36; N, 13.94.
Fig. 5. Interaction map of E-7070 with the active site of hCA II showing similar interactions as those previously reported.

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M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
Fig. 6. Interaction map of compound 6 h with the active site of hCA II showing similar interactions as those previously reported.
4.1.2.2. 4-[2-Amino-3-cyano-4-(p-tolyl)-5,6,7,8-tetrahydroquinolin-
1(4H)-yl]benzenesulfonamide, 6b. Yield 81%; mp 147e149 ꢁC; IR
(KBr, cmꢀ1): 3462, 3375, 3246 (2NH2), 3036 (CH arom.), 2960, 2880
4.1.2.3. 4-[2-Amino-3-cyano-4-(2-hydroxyphenyl)-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6c. Yield 73%; mp
146e148 ꢁC; IR (KBr, cmꢀ1): 3477 (OH), 3383, 3320, 3242 (2NH2),
3068 (CH arom.), 2972, 2940 (CH aliph.), 2187 (ChN), 1310, 1184
(CH aliph.), 2224 (ChN), 1310, 1191 (SO2). 1H NMR (DMSO-d6)
d:
1.0e1.4 [m, 8H, 4CH2 cyclo], 2.4 [s, 3H, CH3], 4.3 [s, 1H, CH], 5.8 [s,
2H, NH2], 6.5e8.4 [m, 10H, AreH þ SO2NH2]. Anal. Calcd. For
C23H24N4O2S: C, 65.69; H, 5.75; N,13.32. Found: C, 65.30; H, 5.80; N,
13.54.
(SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.3 [s, 1H,
CH], 5.7 [s, 2H, NH2], 6.8e8.0 [m, 10H, AreH þ SO2NH2], 8.6 [s, 1H,
OH]. Anal. Calcd. For C22H22N4O3S: C, 62.54; H, 5.25; N, 13.26.
Found: C, 62.62; H, 5.50; N, 13.11.
Fig. 7. Superimposition of compound 6 h (yellow) and E7070 (red) in the active site of hCA II shows that the benzenesulfonamide moieties bound to hCA II overlap each other
completely while the tails adopts slightly different conformations.

M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
3017
4.1.2.4. 4-[2-Amino-3-cyano-4-(4-hydroxyphenyl)-5,6,7,8-tetrahy-
dro-quinolin-1(4H)-yl]benzenesulfonamide, 6d. Yield 77%; mp
140e142 ꢁC; IR (KBr, cmꢀ1): 3477 (OH), 3381, 3319, 3243 (2NH2),
3100 (CH arom.), 2950, 2860 (CH aliph.), 2225 (ChN), 1373, 1149
For C22H21ClN4O2S: C, 59.92; H, 4.80; N, 12.71. Found: C, 60.11; H,
4.70; N, 12.92.
4.1.2.12. 4-[2-Amino-3-cyano-4-(2,4-dichlorophenyl)-5,6,7,8-tetra-
hydroquinolin-1(4H)-yl]benzenesulfonamide, 6l. Yield 91%; mp
238e240 ꢁC; IR (KBr, cmꢀ1): 3418, 3354, 3256 (2NH2), 3090 (CH
arom.), 2960, 2910 (CH aliph.), 2221 (ChN), 1377, 1134 (SO2), 765
(SO2). 1H NMR (DMSO-d6)
d: 1.0e1.4 [m, 8H, 4CH2 cyclo], 4.2 [s, 1H,
CH], 5.8 [s, 2H, NH2], 6.7e8.0 [m, 10H, AreH þ SO2NH2], 9.2 [s, 1H,
OH]. Anal. Calcd. For C22H22N4O3S: C, 62.54; H, 5.25; N, 13.26.
Found: C, 62.23; H, 5.59; N, 12.96.
(C-Cl). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.1 [s, 1H,
CH], 5.7 [s, 2H, NH2], 6.8e7.9 [m, 9H, AreH þ SO2NH2]. MS (m/z):
475.1 [Mþ] (7.6), 44 (100). Anal. Calcd. For C22H20Cl2N4O2S: C,
55.58; H, 4.24; N, 11.79. Found: C, 55.46; H, 4.11; N, 11.55.
4.1.2.5. 4-[2-Amino-3-cyano-4-styryl-5,6,7,8-tetrahydroquinolin-1
(4H)-yl]benzenesulfonamide, 6e. Yield 68%; mp 238e240 ꢁC; IR
(KBr, cmꢀ1): 3477, 3382, 3318 (2NH2), 2217 (ChN), 1311, 1184 (SO2).
1H NMR (DMSO-d6)
d
: 1.0e1.6 [m, 8H, 4CH2 cyclo], 4.0 [s, 1H, CH],
4.1.2.13. 4-[2-Amino-3-cyano-4-(3,4-dichlorophenyl)-5,6,7,8-tetra-
hydroquinolin-1(4H)-yl]benzenesulfonamide, 6m. Yield 88%; mp
208e210 ꢁC; IR (KBr, cmꢀ1): 3419, 3384, 3321, 3254 (2NH2), 3100
(CH arom.), 2970, 2940 (CH aliph.), 2222 (ChN), 1378, 1184 (SO2),
5.7 [s, 2H, NH2], 6.1, 6.4 [2d, 2H, CH]CH, J ¼ 7.3, 7.4 Hz], 7.0e7.8 [m,
11H, AreH þ SO2NH2]. Anal. Calcd. For C24H24N4O2S: C, 66.64; H,
5.59; N, 12.95. Found: C, 66.32; H, 5.49; N, 13.13.
741 (C-Cl). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.2 [s,
4.1.2.6. 4-[2-Amino-3-cyano-4-(2-methoxyphenyl)-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6f. Yield 81%; mp
155e157 ꢁC; IR (KBr, cmꢀ1): 3478, 3384, 3318, 3243 (2NH2), 2228
1H, CH], 5.8 [s, 2H, NH2], 7.1e7.9 [m, 9H, AreH þ SO2NH2]. MS (m/z):
475.05 [Mþ] (9.5), 55 (100). Anal. Calcd. For C22H20Cl2N4O2S: C,
55.58; H, 4.24; N, 11.79. Found: C, 55.46; H, 4.41; N, 11.60.
(ChN),1310,1183 (SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2
cyclo], 3.6 [s, 3H, OCH3], 4.1 [s, 1H, CH], 5.8 [s, 2H, NH2], 6.8e7.9 [m,
10H, AreH þ SO2NH2]. Anal. Calcd. For C23H24N4O3S: C, 63.28; H,
5.54; N, 12.83. Found: C, 63.41; H, 5.77; N, 13.01.
4.1.2.14. 4-[2-Amino-3-cyano-4-(4-hydroxy-3-methoxyphenyl)-
5,6,7,8-tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6n. Yield
79%; mp 161e163 ꢁC; IR (KBr, cmꢀ1): 3478 (OH), 3384, 3319, 3243
(2NH2), 3078 (CH arom.), 2940, 2880 (CH aliph.), 2210 (ChN), 1311,
4.1.2.7. 4-[2-Amino-3-cyano-4-(4-methoxyphenyl)-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6g. Yield 86%; mp
159e161 ꢁC; IR (KBr, cmꢀ1): 3478, 3383, 3319 (2NH2), 2210 (ChN),
1183 (SO2). 1H NMR (DMSO-d6)
d: 0.9e1.3 [m, 8H, 4CH2 cyclo], 3.8
[s, 3H, OCH3], 4.3 [s, 1H, CH], 5.7 [s, 2H, NH2], 6.5e7.4 [m, 10H,
AreH þ SO2NH2 þ OH]. Anal. Calcd. For C23H24N4O4S: C, 61.05; H,
5.35; N, 12.38. Found: C, 61.24; H, 5.47; N, 12.02.
1311, 1183 (SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2 cyclo],
3.7 [s, 3H, OCH3], 4.2 [s, 1H, CH], 5.7 [s, 2H, NH2], 6.5e8.0 [m, 10H,
AreH þ SO2NH2]. Anal. Calcd. For C23H24N4O3S: C, 63.28; H, 5.54; N,
12.83. Found: C, 63.29; H, 5.33; N, 12.94.
4.1.2.15. 4-[2-Amino-3-cyano-4-(3-ethoxy-4-methoxyphenyl)-
5,6,7,8-tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6o. Yield
71%; mp 135e137 ꢁC; IR (KBr, cmꢀ1): 3310, 3280, 3210 (2NH2),
2978, 2890 (CH aliph.), 2222 (ChN), 1397, 1178 (SO2). 1H NMR
4.1.2.8. 4-[2-Amino-4-(benzo[d][1,3]dioxol-5-yl)e3ecyano-5,6,7,8-
tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6h. Yield 79%;
mp 178e180 ꢁC; IR (KBr, cmꢀ1): 3350, 3310, 3293 (2NH2), 2925,
2886 (CH aliph.), 2225 (ChN), 1390, 1155 (SO2). 1H NMR (DMSO-d6)
(DMSO-d6) d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 1.3 [t, 3H, CH3], 3.8 [s, 3H,
OCH3], 4.2 [q, 2H, CH2], 6.5 [s, 1H, CH], 6.9 [s, 2H, NH2], 7.0e8.5 [m,
9H, AreH þ SO2NH2]. Anal. Calcd. For C25H28N4O4S: C, 62.48; H,
5.87; N, 11.66. Found: C, 62.69; H, 5.71; N, 11.49.
d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.4 [s, 1H, CH], 5.8 [s, 2H, NH2], 6.1 [s,
2H, O-CH2-O], 7.0e8.5 [m, 9H, AreH þ SO2NH2]. MS (m/z): 450.1
[Mþ] (2.62), 40 (100). Anal. Calcd. For C23H22N4O4S: C, 61.32; H,
4.92; N, 12.44. Found: C, 61.43; H, 5.24; N, 12.10.
4.1.2.16. 4-[2-Amino-3-cyano-4-(2,4,5-trimethoxyphenyl)-5,6,7,8-
tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6p. Yield 78%;
mp 141e143 ꢁC; IR (KBr, cmꢀ1): 3478, 3384, 3319, 3243 (2NH2),
2951, 2837 (CH aliph.), 2216 (ChN), 1342, 1191 (SO2). 1H NMR
4.1.2.9. 4-[2-Amino-3-cyano-4-(3-nitrophenyl)-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6i. Yield 78%; mp
264e266 ꢁC; IR (KBr, cmꢀ1): 3417, 3348, 3252 (2NH2), 3091 (CH
arom.), 2960, 2910 (CH aliph.), 2223 (ChN), 1352, 1153 (SO2). 1H
(DMSO-d6) d: 0.9e1.4 [m, 8H, 4CH2 cyclo], 3.7, 3.92, 3.94 [3s, 9H, 3
CH3], 4.1 [s, 1H, CH], 5.8 [s, 2H, NH2], 6.5e8.1 [m, 8H,
AreH þ SO2NH2]. Anal. Calcd. For C25H28N4O5S: C, 60.47; H, 5.68; N,
11.28. Found: C, 60.16; H, 5.48; N, 11.00.
NMR (DMSO-d6) d: 1.0e1.5 [m, 8H, 4CH2 cyclo], 4.3 [s, 1H, CH], 5.7
[s, 2H, NH2], 6.8e7.6 [m, 10H, AreH þ SO2NH2]. MS (m/z): 451.05
[Mþ] (6.3), 43 (100). Anal. Calcd. For C22H21N5O4S: C, 58.52; H, 4.69;
N, 15.51. Found: C, 58.70; H, 4.79; N, 15.21.
4.1.2.17. 4-[2-Amino-3-cyano-4-(2-hydroxynaphthalen-1-yl)-5,6,7,8-
tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6q. Yield 89%; mp
264e266 ꢁC; IR (KBr, cmꢀ1): 3490 (OH), 3335, 3233, 3210 (2NH2),
3093 (CH arom.), 2970, 2920 (CH aliph.), 2208 (ChN), 1343, 1176
4.1.2.10. 4-[2-Amino-3-cyano-4-(4-nitrophenyl)-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6j. Yield 83%; mp
157e159 ꢁC; IR (KBr, cmꢀ1): 3470, 3384, 3315, 3243 (2NH2), 2219
(SO2). 1H NMR (DMSO-d6)
d: 1.0e1.6 [m, 8H, 4CH2 cyclo], 4.2 [s, 1H,
CH], 5.8 [s, 2H, NH2], 6.7e7.9 [m, 12H, AreH þ SO2NH2]., 8.6 [s, 1H,
OH]. MS (m/z): 472.1 [Mþ] (5.6), 73 (100). Anal. Calcd. For
C26H24N4O3S: C, 66.08; H, 5.12; N, 11.86. Found: C, 66.22; H, 5.23; N,
11.60.
(ChN), 1311, 1183 (SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5 [m, 8H, 4CH2
cyclo], 4.2 [s, 1H, CH], 5.8 [s, 2H, NH2], 6.7e7.8 [m, 10H,
AreH þ SO2NH2]. Anal. Calcd. For C22H21N5O4S: C, 58.52; H, 4.69; N,
15.51. Found: C, 58.40; H, 4.55; N, 15.30.
4.1.2.18. 4-[2-Amino-3-cyano-4-(2-methoxynaphthalen-1-yl)-5,6,7,8-
tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6r. Yield 77%; mp
146e148 ꢁC; IR (KBr, cmꢀ1): 3410, 3375, 3280 (2NH2), 2970, 2910 (CH
4.1.2.11. 4-[2-Amino-4-(2-chlorophenyl)e3ecyano-5,6,7,8-tetrahy-
droquinolin-1(4H)-yl]benzenesulfonamide, 6k. Yield 68%; mp
163e165 ꢁC; IR (KBr, cmꢀ1): 3463, 3376, 3272 (2NH2), 2212 (ChN),
aliph.), 2227 (ChN), 1381, 1192 (SO2). 1H NMR (DMSO-d6)
d: 1.0e1.5
1335, 1186 (SO2), 721 (C-Cl). 1H NMR (DMSO-d6)
d
: 1.0e1.5 [m, 8H,
[m, 8H, 4CH2 cyclo], 3.9 [s, 3H, OCH3], 4.2 [s, 1H, CH], 5.8 [s, 2H, NH2],
7.0e8.8 [m, 12H, AreH þ SO2NH2]. Anal. Calcd. For C27H26N4O3S: C,
66.65; H, 5.39; N, 11.51. Found: C, 66.51; H, 5.30; N, 11.22.
4CH2 cyclo], 4.3 [s, 1H, CH], 5.8 [s, 2H, NH2], 6.9e7.9 [m, 10H,
AreH þ SO2NH2]. MS (m/z): 440.1 [Mþ] (4.1), 56 (100). Anal. Calcd.

3018
M.S. Al-Said et al. / European Journal of Medicinal Chemistry 45 (2010) 3011e3018
4.1.2.19. 4-[2-Amino-3-cyano-4-(4-methoxynaphthalen-1-yl)-5,6,7,8-
tetrahydroquinolin-1(4H)-yl]benzenesulfonamide, 6s. Yield 79%; mp
159e161 ꢁC; IR (KBr, cmꢀ1): 3447, 3380, 3220 (2NH2), 2992, 2950
percentage of non-viable cells after 2 h of incubation [24]. The
results of in vitro antitumor screening are presented in Table 1.
(CH aliph.), 2218 (ChN), 1372, 1167 (SO2). 1H NMR (DMSO-d6)
d:
4.3. Docking studies
1.1e1.5 [m, 8H, 4CH2 cyclo], 3.8 [s, 3H, OCH3], 4.3 [s, 1H, CH], 5.7 [s,
2H, NH2], 6.8e8.1 [m, 12H, AreH þ SO2NH2]. Anal. Calcd. For
C27H26N4O3S: C, 66.65; H, 5.39; N, 11.51. Found: C, 66.55; H, 5.61; N,
11.44.
All molecular modeling calculations and docking studies were
performed using “Molecular Operating Environment (MOE) version
2007.09”.
The ligand was drawn on ChemDraw and imported in MOE. The
structure was subjected to energy minimization using MMFF94ꢄ
forcefield and the partial charges were computed using the same
forcefield.
The X-ray crystallographic structure of hCA II complexed with N-
(2,3,4,5,6-pentafluoro-benzyl)-4-sulfamoyl-benzamide (1g54) was
obtained from the Protein Data Bank. The enzyme was prepared for
the docking studies where: (i) the ligand molecule was removed
from the enzyme active site. (ii) Hydrogen atoms were added to the
structure with their standard geometry. (iii) Partial charges were
computed using Amber99 forcefield.
4.1.2.20. 4-[2-Amino-3-cyano-4-(5-methylfuran-2-yl)-5,6,7,8-tetra-
hydroquinolin-1(4H)-yl]benzenesulfonamide, 6t. Yield 66%; mp
163e165 ꢁC; IR (KBr, cmꢀ1): 3420, 3384, 3200 (2NH2), 2950, 2920
(CH aliph.), 2211 (ChN), 1334, 1157 (SO2). 1H NMR (DMSO-d6)
d:
0.9e1.4 [m, 8H, 4CH2 cyclo], 2.4 [s, 3H, CH3], 4.2 [s, 1H, CH], 5.7 [s,
2H, NH2], 6.5e8.1 [m, 8H, AreH þ SO2NH2]. Anal. Calcd. For
C21H22N4O3S: C, 61.44; H, 5.40; N, 13.65. Found: C, 61.46; H, 5.26; N,
13.41.
4.1.2.21. 4-[2-Amino-3-cyano-4-(thiophen-2-yl)-5,6,7,8-tet-
rahydroquinolin-1(4H)-yl]benzenesulfonamide, 6u. Yield 63%;
mp 151e153 ꢁC; IR (KBr, cmꢀ1): 3384, 3318, 3242 (2NH2), 3094 (CH
arom.), 2970, 2886 (CH aliph.), 2162 (ChN), 1310, 1183 (SO2). 1H
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Ehrlich ascites carcinoma (EAC) cells were maintained in female
Swiss albino mice weighing 25e30 g (the holding company for
biological products and vaccines. VACSERA, Cairo, Egypt) were
housed at a constant temperature (24 ꢂ 2 ꢁC) with alternating 12-h
light and dark cycles and fed standard laboratory food (Milad Co,
Cairo, Egypt) and water ad libitum. All chemicals and reagents were
of the highest grade commercially available by the National Center
for Radiation Research and Technology (NCRRT), Atomic Energy
Authority (AEA), Cairo, Egypt. Animal care and handling was done
according to the guidelines set by the world heath organization,
Geneva, Switzerland and approved from the committee for animals
care at NCRRT, AEA.
Ehrlich Ascites Carcinoma (EAC) cells were obtained by needle
aspiration of ascetic fluid from preinoculated mice; under aseptic
conditions. Tumor cells suspension (2.5 ꢄ106 per ml) was prepared
with various dilutions by dissolving; 100, 50, 25 and 10
tested compounds in DMSO (1 ml).
mg of the
In a set of sterile test tubes 0.8 ml RPMI-1640 media containing
(glutamine, fetal calf serum as nutrient, streptomycin and peni-
cillin), 0.1 ml of each of the tested compounds (corresponding to
100, 50, 25, 10 mg) were mixed then 0.1 ml of tumor cell suspension
(2 ꢄ106) was added. The test tubes were incubated at 37 ꢁC for 2 h.
Trypan blue exclusion test was carried out to calculate the