Discovering some novel 7-chloroquinolines carrying a biologically active benzenesulfonamide moiety as a new class of anticancer agents

Article abstract of DOI:10.1248/cpb.c12-00812

Based on the reported anticancer activity of quinolines, a new series of 7-chloroquinoline derivatives bearing the biologically active benzenesulfonamide moiety 2-17 and 19-25 were synthesized starting with 4,7-dichloroquinolne 1. Compound 17 was the most active compound with IC₅₀ value 64.41, 75.05 and 30.71μm compared with Doxorubicin as reference drug with IC₅₀ values 82.53, 88.32 and 73.72 μm on breast cancer cells, skin cancer cells and neuroblastoma, respectively. All the synthesized compounds were evaluated for their in vitro anticancer activity on breast cancer cells, skin cancer cells and neuroblastoma cells. Most of the synthesized compounds showed moderate activity. In order to suggest the mechanism of action for their cytotoxic activity, molecular docking for all synthesized compounds was done on the active site of phosphoinositide kinase (PI3K) and good results were obtained.

Full text of DOI:10.1248/cpb.c12-00812

Regular Article
50
Vol. 61, No. 1
Chem. Pharm. Bull. 61(1) 50–58 (2013)
Discovering Some Novel 7-Chloroquinolines Carrying a Biologically
Active Benzenesulfonamide Moiety as a New Class of Anticancer Agents
,b
Mohammed Salem Al-Dosari,a Mostafa Mohamed Ghorab,* Mansour Sulaiman Al-Said,b and
Yassin Mohammed Nissanc
b
a Pharmacognosy Department, College of Pharmacy, King Saud University; Medicinal, Aromatic and Poisonous
Plants Research Center (MAPPRC), College of Pharmacy, King Saud University; P.O. Box 2457, Riyadh 11451, Saudi
c
Arabia: and Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University; Cairo 11562, Egypt.
Received September 16, 2012; accepted October 16, 2012
Based on the reported anticancer activity of quinolines, a new series of 7-chloroquinoline deriva-
tives bearing the biologically active benzenesulfonamide moiety 2–17 and 19–25 were synthesized starting
with 4,7-dichloroquinolne 1. Compound 17 was the most active compound with IC50 value 64.41, 75.05 and
30.71 µm compared with Doxorubicin as reference drug with IC50 values 82.53, 88.32 and 73.72µm on breast
cancer cells, skin cancer cells and neuroblastoma, respectively. All the synthesized compounds were evalu-
ated for their in vitro anticancer activity on breast cancer cells, skin cancer cells and neuroblastoma cells.
Most of the synthesized compounds showed moderate activity. In order to suggest the mechanism of action
for their cytotoxic activity, molecular docking for all synthesized compounds was done on the active site of
phosphoinositide kinase (PI3K) and good results were obtained.
Key words qunioline; sulfonamide; anticancer activity
Many quinoline derivatives possess a wide variety in phar- such as cell cycle perturbation in the G1 phase, disruption of
macological activity.1–3) The quinoline pattern is found in a microtubule assembly, angiogenesis inhibition, and functional
large number of natural products and drug-like compounds suppression of the transcriptional activator NF-Y. Moreover,
known as antitumor agents, such as Camptothecin,4) Luo- following an extensive evaluation, numerous sulfonamides
tonin,5) Ascididemin,6) TAS-103,7) Cryptolepin,8) Indolo[2,3- were found to act as carbonic anhydrase (CA) inhibitors.16–18)
b]quinolines.9) In addition, sulfonamides constitute an im- Recently, combination of quinoline nuclues with sulfonamide
portant class of drugs with several types of pharmacological moieties has received a great attention in seeking for novel
activities including antibacterial,10) anti-carbonic anhydrase,11) anticancer agents.19) Several quinoline sulfonamide derivatives
diuretic,12) hypoglycemic,13) antitumor2) and antithyroid activ- showed potent anticancer activity as phosphoinisitol kinase
ity.14) Some structurally novel sulfonamide derivatives have re- (PI3K) inhibitors.19) In view of the above mentioned findings
cently been reported to show substantial antitumor activity in and as a part of our research effort to explore novel anticancer
vitro and/or in vivo. Compounds such as E7010 A, ER-34410 heterocyclic compounds20,21) we have synthesized a new se-
B, E7070 Indisulam C, QBS D and the quinoline derivative E ries of chloroquinoline derivatives having biologically active
are examples for antitumor sulfonamides in advanced clinical sulfonamide moiety as analogues for compounds A–E. The
trials.15) It has been known that aryl/heteroaryl sulfonamides cytotoxic activity of the newly synthesized compounds were
may act as antitumor agents through a variety of mechanisms evaluated through in vitro antitumor screening on several cell
The authors declare no conflict of interest.
© 2013 The Pharmaceutical Society of Japan
*To whom correspondence should be addressed. e-mail: mmsghorab@yahoo.com

January 2013
51
1
10.2–10.7ppm for NHph. H-NMR spectrum of compound 16
exhibited singlet at 5.7ppm due to NH2 group. On the other
hand, 4-(7-chloroquinolin-4-ylamino)-N-(phenylcarbamoyl)-
benzenesulfonamide 15 was obtained in a good yield via
reaction of compound 2 with phenyl isocyanate in dry DMF
in the presence of anhydrous potassium carbonate. Compound
15 was confirmed by elemental analysis as well as spectral
data. The IR spectrum for compound 15 revealed the presence
of bands corresponding to (NH), (C=O), (C=N), (SO2) and
1
(C–Cl) groups. Its H-NMR spectrum in (DMSO-d6) showed
singlet at 8.4ppm for NHCO group. When compound 16 was
reacted with phenyl isocyanate in dry DMF the correspond-
ing ureido derivative 17 was obtained. The IR spectrum of
compound 17 revealed the presence of bands correspond-
1
ing to (NH), (C=O), (SO2) groups. Its H-NMR spectrum in
(DMSO-d6) showed signals at 9.1, 9.2ppm assigned to 2NH of
ureido groups.
Isothiocyanate derivatives are useful and widely used as
building blocks in the synthesis of nitogen, sulfur and oxy-
gen containing heterocyclic compounds and organometallic
compounds of academic, pharmaceutical and industrial inter-
est. Thus, the isothiocyanate derivative 18 was synthesized
by treatment of compound 1 with ammonium thiocyanate in
dry acetone for 1h. This method lead to a higher overall yield
and shorter working time in comparison with the reported
method by using silver thiocyanate.23) IR spectrum of 18
showed band at 2072cm−1 (N=C=S). The reactivity of iso-
thiocyanate derivative 18 towards amino compounds such as
Chart 1. Synthetic Pathways for Compounds 2–14
lines. Moreover, as a trial to suggest the mechanism of action sulfonamides was discussed. Thus, interaction of compound
of these compounds virtual docking on the active site of PI3K 18 with sulfonamides in DMF in the presence of triethylamine
was performed.
yielded the corresponding carbamimidothioic acid derivatives
19–25, respectively. The structures of compounds 19–25 were
supported by analytical and spectral data. The IR spectra of
compounds 19–25 showed the absence of (N=C=S) band and
presence of bands for (NH), (C=N), (SO2) and (C–Cl) groups.
1H-NMR spectra in (DMSO-d6) for compounds 19–25 showed
signals at 2.2–2.5ppm for SH groups, and 8.4–8.9ppm due to
SO2NH group.
Molecular Docking Oncology drug discovery has benefit-
ed significantly from progress in understanding how to target
kinases with small molecules relative to other disease indica-
tions. The constitutive activity of this class of kinase target
makes them essential for survival and/or proliferation of the
Chart 2. Synthetic Pathway for Compound 15
Results and Discussion
Chemistry Several compounds were designed with the cancer cell. This so-called oncogene addiction.24,25) A recent
aim of exploring their anticancer properties (Charts 1–3). The example is that PTen-deficient cancers depend on PI3Kβ to
present work reports the possible utility of 4,7-dichloroquino- sustain activation of the PI3K pathway, whereas PI3Kα kinase
line 1 in the synthesis of 7-chloroquinolinesulfonamide de- activity appears to be required to sustain the proliferation of
rivatives 2–17 and 19–25. Quninolinesulfonamide derivatives established tumours.26,27) Like the majority of protein kinase
2–14 were obtained in good yield by the reaction of compound inhibitors, all existing PI3K inhibitors bind competitively in
1 with several sulfonamides in dry N,N-dimethylformamide the ATP-binding pocket of the catalytic domain. This strategy
(DMF), whereas, conducting this reaction in the presence of has enabled the development of both pan-PI3K- and isoform-
anhydrous potassium carbonate22) afforded the correspond- specific inhibitors. Loosely discriminate inhibitors that target
ing sulfonamide derivative 16. The structures of 2–14 and 16 multiple PI3K isoforms may more thoroughly shut down PI3K
were supported by elemental analysis and spectral data. The signaling for the treatment of acute life-threatening diseases.28)
IR spectra of compounds 2–14 revealed the presence of bands
The PI3K (phosphoinositide 3-kinase) pathway is often
for NH, CH aromatic, C=N, SO2 and C–Cl. IR spectrum overactive in human cancers, and various genetic alterations
for compound 16 showed bands at 3454, 3389 and 3244cm−1 have been found to cause this. In all cases, PI3K inhibition is
(NH, NH2), 1627cm−1 (C=N), 1363, 1136cm−1 (SO2), 808cm−1 considered to be one of the most promising targeted therapies
(C–Cl). 1H-NMR spectra of compounds 2–14 in (DMSO- for cancer treatment. In our investigation three different cell
d6) indicated the presence of a doublet at 6.5–8.6ppm lines were chosen for in vitro assay. It was reported that these
which could be assigned to 2CH of pyridine and a singlet at cell lines were affected by PI3K inhibitors with high cytotoxic

52
Vol. 61, No. 1
Chart 3. Synthetic Pathways for Compounds 16–25
882 with a hydrogen bond of 2.90Å, Tyr 867 with a hydrogen
bond of 3.33Å, Asp 864 with a hydrogen bond of 3.33Å, Lys
833 with a hydrogen bond of 3.33Å, Ser 806 with a hydrogen
bond of 3.74Å and Asp 841 with a hydrogen bond of 2.79Å
through a water molecule. All synthesized compounds were fit
to the active site of PI3K enzyme with good energy scores (S)
suggesting activity as PI3K inhibitors. Energy scores (S) and
amino acid interactions for the synthesized compounds were
listed in Table 1. Compound 21 gave the best energy score
(S)=−24.4292 and interacted with Lys 802 with a hydrogen
bond of 3.76Å, Lys 833 with a hydrogen bond of 2.64Å, Ser
806 with a hydrogen bond of 2.33Å, Lys 805 with a hydrogen
bond of 2.88Å and with His 867 with a hydrogen bond of
3.83Å, Fig. 2.
The best amino acid interactions were formed with com-
pound 19 with Lys 890 with a hydrogen bond of 2.92Å, Lys
833 with a hydrogen bond of 2.52, 3.06Å, Asp 864 with a
hydrogen bond of 3.24, 3.62Å and Tyr 867 through a water
molecule with a hydrogen bond of 2.93Å, Fig. 3.
In Vitro Antitumor Activity The newly synthesized
compounds were evaluated for their in vitro cytotoxic activ-
ity against human breast cancer cell line (MDA-MB231),
skin cancer cell line (HT 1080) and neuroblastoma cell line
(SH-SY5Y). Doxorubicin which is one of the most effective
anticancer agents was used as the reference drug in this study.
The relationship between surviving fraction and drug concen-
tration was plotted to obtain the survival curve of cancer cell
Fig. 1. Co-crystallized Quinoline Ligand on the Active Site of Phos-
phoinositide Kinase (PI3K)
activity.29,30)
Based on the previous findings and as a trial to suggest the
mechanism of action of the cytotoxic activity for the synthe-
sized compounds docking of all newly synthesized compounds
was done on the active site of PI3K.
The protein data bank file (PDB: 3S2A) was selected for
value,
lines. The response parameter calculated was the IC50
this purpose. The file contains PI3K enzyme co-crystallized which corresponds to the concentration required for 50% in-
with a quinoline ligand. All docking procedures were hibition of cell viability. Table 2 shows the in vitro cytotoxic
achieved by Molecular Operating Environment (MOE) soft- activity of the synthesized compounds where all compounds
ware 10.2008 provided by chemical computing group, Canada. exhibited moderate activity compared to the reference drug in
Docking on the active site of PI3K enzyme was performed for case of human breast cancer cell line (MDA-MB231), while
all synthesized compounds.
compounds 19–25 where inactive in case of skin cancer cell
Docking protocol was verified by redocking of the co-crys- line (HT 1080). Also compounds 20–23 and 25 were inactive
tallized ligand in the vicinity of the active site of the enzyme in case of neuroblastoma cell line (SH-SY5Y).
with energy score (S)=−29.8249kcal/mol and root mean stan-
All the synthesized compounds showed moder-
dard deviation (RMSD)=1.9094, Fig. 1. The quinoline ligand ate cytotoxic activity compared to Doxorubicin on
interacts with the active site of PI3K by six interactions: Val human breast cancer cell line (MDA-MB231). The

January 2013
53
Fig. 2. Compound 21 on the Active Site of PI3K
Table 1. Binding Scores and Amino Acid Interactions of the Docked Compounds on the Active Site of Phosphoinisitol Kinase (PI3K)
Compound No.
S (kcal/mol)
Amino acid interactions
Interacting groups
H bond length Å
2
−12.3409
Lys 833, Asp 841 (water)
Val 882, Asp 964
Lys 833, Asp 841 (water)
Lys 890, Asp 964
Lys 890, Tyr 867
Asp 864, Asp 841
Lys 833, Lys 890
Lys 890, Lys 833
Ser 806, Asp 864
Lys 890, Asp 846
Tyr 867, Lys 833
Lys 833, Lys 890
Lys 890
SO2, N-quinoline, SO2, SO2 3.02, 2.543.42, 3.63
3
4
−17.9656
−16.2910
SO2, NHCO, N-quinoline,
NHCO
N-quinoline, SO2SO2, SO2
3.31, 2.672.59, 3.33
2.82, 3.642.85, 2.66
5
6
−21.0847
−20.0851
SO2, N-quinoline
2.73, 2.50
N-quinoline, SO2SO2, NH
2.61, 2.353.28, 1.25
7
8
−22.2882
−20.8781
N-quinoline, SO2SO2, N-
thiazole
N-quinoline, SO2SO2
2.91, 3.803.33, 2.31
2.67, 2.52–2.90
9
10
−21.7370
−20.0596
Asp 864 (water), Lys 890
Val 882, Lys 802
Lys 833
N-quinoline, SO2
N-quinoline, SO2SO2
3.72, 2.38
3.25, 2.433.41
11
12
−19.5996
−22.4876
Lys 833, Asp 841 (water)
Asp 864 (water), Tyr 867
Lys 890, Lys 890
Tyr 867, Asp 864 (water)
Lys 890, Lys 890
Asp 841 (water), Lys 890
Lys 802
Val 882, Ser 806
Lys 833, Asp 864
Val 882, Tyr 864
Asp 864 (water),
Asp 864
N-quinoline, SO2
N-quinoline, SO2, N-py-
rimidine
3.20, 3.56
3.02, 3.763.35, 2.50
13
14
15
16
−21.3247
−21.2363
−21.8738
−14.8566
N-quinoline, SO2
3.17, 2.723.66, 3.86
3.55, 2.453.03
N-quinoline, SO2OCH3
N-quinoline, NHSO2, NH
N-quinoline, SO2SO2, NH2
3.56, 2.972.81, 2.92
3.05, 3.093.21, 1.39
17
19
−19.3479
−20.3214
Ser 806, Asp 864
Tyr 867, Asp 864 (water)
Lys 890, Lys 833
Lys 833, Asp 864Asp
864, Tyr 867 (water)
Lys 890, Ser 806
Lys 833, Asp 864
Lys 802, Lys 833
Ser 806, Lys 805
Val 882, Lys 833
Ser 806, Asp 864
Lys 890, Tyr 867
Asp 864, Asp 841
(water)
N-quinoline, SO2SO2
2.82, 3.013.78, 3.60
N-quinoline, NHSO2,
NHSO2
2.92, 3.523.60, 3.243.62,
2.93
20
21
22
23
−18.4624
−24.4292
−17.4305
−20.9130
N-quinoline, SO2SO2,
SO2NH
N-quinoline, SO2SO2NH,
N-isoxazole
N-quinoline, SO2SO2,
SO2NH
N-quinoline, SO2SO2
2.82, 3.593.37, 1.48
3.76, 2.642.33, 2.88
3.60, 2.743.21, 1.24
2.63, 3.183.06, 3.41
24
25
−23.4308
−23.3010
Asp 841 (water), Lys 833
Lys 833, Lys 805
Asp 841 (water), Lys 833
Asp 864, Lys 805
N-quinoline, SO2SO2, imino 2.80, 2.282.95, 3.00
N-quinoline, imino, NH,
3.29, 2.342.54, 3.27
SO2

54
Vol. 61, No. 1
Fig. 3. Compound 19 on the Active Site of PI3K
N-(4-sulfamoylphenyl)carbamimidothioic acid derivative 19
was the most active compound with IC50 value 45.92µm which
was better than that of Doxorubicin. On the other hand, quino-
line sulfonamide derivatives 2–14 showed IC50 values ranging
from 82.88–154.87µm. The unsubstituted sulfonamide deriva-
tive 2 showed IC50 value 114.4.40µm. Upon substitution on N
of sulfonamide group with acetyl group as in compound 3
or guanidine as in compound 4 or 5-membered heterocyclic
substituents as in compounds 5–8 the activity drops except for
compound 6 with dimethyl isoxazole substituent in which the
activity increased with IC50 value 82.88µm. This was not the
case in 6-membered substitutions as in compounds 9–14 as
the activity tends to be the same or increased especially with
5,6-dimethoxypyrimidine substituent as in compound 14 with
IC50 value 95.43µm. Compounds 16–25 showed better activ-
ity except for compound 21 with IC50 value 120.99µm. The
best two compounds were the unsubstituted sulfonamide urea
derivative 17 with IC50 value 64.41µm and the unsubstituted
cabamimidothioic acid derivative 19 with IC50 value 45.92µm.
Most of the synthesized compounds showed moderate cy-
totoxic activity on skin cancer cell line (HT 1080) except for
compounds 19–25. The most active compound was the unsub-
stituted sulfonamide derivative 17 with IC50 value 75.05µm.
For compounds 2–14 better activity also was observed for
6-membered substituted sulfonamide derivatives 9–14 than
unsubstituted 2, acetyl 3, guanidine 4 and 5-membered sub-
stituted derivatives 5–8. On the other hand, the sulfonamide
phenyl urea derivative 15 showed better activity than com-
pound 16 with IC50 value 109.40µm and 140.99µm, respec-
tively.
Table 2. In Vitro Anticancer Screening of the Synthesized Compounds
against Human Breast Cells, Skin Cancer Cells and Neuroblastoma
MDA-MB231
HT 1080 (skin SH-SYSY (neuro-
(breast cancer
cancer cells)
blastoma cells)
Compound No.
cells)
IC50 (µm)
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
114.40
154.09
129.55
135.01
82.88
137.73
154.87
117.43
112.70
115.46
103.53
97.47
95.43
70.21
107.74
64.41
45.92
173.50
223.24
230.82
156.07
219.99
139.72
177.22
136.41
139.42
128.55
94.66
127.35
107.22
109.40
140.99
75.05
NA
43.92
50.42
59.12
115.46
106.41
85.14
56.01
76.64
130.46
105.90
87.40
204.70
106.79
84.23
72.64
30.71
35.41
NA
19
20
88.05
NA
21
22
120.99
97.41
NA
NA
NA
NA
23
72.09
NA
NA
24
25
68.66
78.50
NA
NA
124.77
NA
Doxorubicin
82.53
88.32
73.72
Most of the synthesized compounds showed moderate cyto-
toxic activity compared to Doxorubicin on neuroblastoma cell

January 2013
55
line (SH-SY5Y) except for compounds 20–23 and 25. Activity
4-(7-Chloroquinolin-4-yl-amino)benzenesulfonamide
(2):
on this cell line was much higher for all active compounds Yield 94%, melting point 263.4°C. IR: νmax/cm−1 3420, 3296
with IC50 values in the range 30.71–130.46µm. The most ac- (NH, NH2), 1610 (C=N), 1325, 1155 (SO2), 817 (C–Cl).
tive compound was compound 17 with IC50 value 30.71µm. 1H-NMR (DMSO-d6, D2O) δ: 6.9, 8.5 (2d, 2H, 2CH pyridine,
Also a remarkable activity was attributed to compound 19 J=7.4Hz), 7.1–7.9 (m, 9H, Ar-H+SO2NH2), 10.7 (s, 1H, NH,
with IC50 value 35.41µm. Compounds 2–16 showed IC50 val- D2O-exchangeable). 13C-NMR (DMSO-d6) δ: 112.4, 118.7 (2),
ues 43.92–204.70µm while compound 24 showed IC50 value 121.2, 125.4, 126.7, 127.2 (2), 127.3, 135.2, 139.8, 146.8, 148.4,
124.77 µm.
Relationship between Molecular Docking and in Vitro H, 3.62; N, 12.59. Found: C, 53.76; H, 3.82; N, 12.33.
Screening The inhibition of PI3K could be a suggested N-(4-(7-Chloroquinolin-4-yl-amino)phenylsulfonyl)-
149.8, 151.9. Anal. Calcd for C15H12ClN3O2S (333.79): C, 53.97;
mechanism for the cytotoxic activity of the synthesized com- acetamide (3): Yield 88%, melting point 245.5°C. IR: νmax
/
pound. This can be demonstrated by the docking results that cm−1 3489, 3320 (NH), 3053 (CH arom.), 2920, 2899 (CH
were performed on the active site of PI3K. The co-crystalized aliph.), 1650 (C=O), 1614 (C=N), 1360, 1165 (SO2), 815 (C–
1
quinoline ligand intearcts with the amino acids of the ac- Cl). H-NMR (DMSD-d6, D2O) δ: 3.1 (s, 3H, COCH3), 6.9, 8.6
tive site by six interaction that were mentioned before. On (2d, 2H, 2CH pyridine, J=7.8Hz), 7.0–8.3 (m, 7H, Ar-H), 11.4
the other hand, the newly synthesized compounds interact (s, 1H, NHPh, D2O-exchangeable), 15.1 (s, 1H, NHCO, D2O-
with these amino acids by 1, 2, 3 or 4 interactions. We could exchangeable). 13C-NMR (DMSD-d6) δ: 19.2, 114.2, 116.3(2),
postulate a relationship between the number on amino acid 119.3, 125.0, 126.3, 127.3(2), 127.5, 138.4, 139.1, 140.2, 142.2,
interactions and the in vitro cytotoxic activity on the used cell 143.7, 154.3, 176.4. Anal. Calcd for C17H14ClN3O3S (375.83): C,
lines. Most of the synthesized compounds interact with the 54.33; H, 3.75; N, 11.18. Found: C, 54.60; H, 3.51; N, 11.38.
amino acids of the active site by 3 interactions. Compounds
N-Carbamimidoyl-4-(7-chloroquinolin-4-yl-amino)-
2, 3, 4, 6, 7, 16, 17, 19, 20, 23 and 25 showing good activity benzenesulfonamide (4): Yield 84%, melting point 137.1°C.
on one or more cell lines with IC50 values 43.92µm (neuroblas- IR: νmax/cm−1 3470, 3300 (NH, NH2), 3075 (CH arom.), 1612
1
toma), 50.42µm (neuroblastoma), 59.12µm (neuroblastoma), (C=N), 1325, 1134 (SO2), 841 (C–Cl). H-NMR (DMSD-d6,
82.88µm (MDA-MB231), 85.14µm (neuroblastoma), 72.64µm D2O) δ: 4.7 (hump, 1H, NH imino, D2O-exchangeable), 6.6,
(neuroblastoma), 30.71µm (neuroblastoma), 35.41µm (neuro- 8.5 (2d, 2H, 2CH pyridine, J=7.5Hz), 6.9 (s, 2H, NH2, D2O-
blastoma), 88.05µm (MDA-MB321), 72.09µm (MDA-MB321) exchangeable), 7.0–8.4 (m, 8H, Ar-H+SO2NH), 10.4 (s, 1H,
and 78.50µm (MDA-MB321), respectively. Compounds 15 NHPh, D2O-exchangeable). 13C-NMR (DMSD-d6) δ: 114.9,
and 22 interact with the amino acids of the active site by 4 117.3(2), 122.3, 123.2, 125.1, 126.2(2), 127.1, 136.2, 140.4,
interactions showing good cytotoxic activity for compound 144.1, 147.7, 150.1, 152.7, 158.1. Anal. Calcd for C16H14ClN5O2S
15 and moderate activity for compound 22 with IC50 values (375.83): C, 51.13; H, 3.75; N, 18.63. Found: C, 51.41; H, 3.48;
of 70.21µm (MD-MB321) and 97.41µm (MD-MB321), respec- N, 18.94.
tively. This could be explained by the weak docking score of
4-(7-Chloroquinolin-4-yl-amino)-N-(3-methyl-isoxazol-5-
compound 22 (−17.4305kcal/mol) indicating improper fitting yl)benzenesulfonamide (5): Yield 91%, melting point 162.9°C.
on the active site of the enzyme PI3K. The rest on the newly IR: νmax/cm−1 3320, 3210 (NH), 3059 (CH arom.), 2926,
synthesized compounds interact with amino acids of the active 2812 (CH aliph.), 1616 (C=N), 1375, 1145 (SO2), 813 (C–Cl).
site by one or two interactions showing moderate, weak or no 1H-NMR (DMSD-d6, D2O) δ: 2.3 (s, 3H, CH3), 6.7 (s, 1H, CH
activity in the in vitro screening.
isoxazole), 6.8, 8.5 (2d, 2H, 2CH pyridine, J=7.2Hz), 7.1–8.4
(m, 8H, Ar-H+SO2NH), 10.6 (s, 1H, NHPh, D2O-exchange-
able). 13C-NMR (DMSD-d6) δ: 12.0, 103.1, 115.2, 118.6(2),
Experimental
Chemistry Melting points (°C, uncorrected) were de- 121.5, 123.3, 127.2, 127.7(2), 128.7, 131.2, 139.1, 146.1, 148.8,
termined in open capillaries on a Gallenkemp melting point 149.2, 152.8, 157.6, 162.2. Anal. Calcd for C19H15ClN4O3S
apparatus (Sanyo Gallenkemp, Southborough, U.K.) and were (414.87): C, 55.01; H, 3.64; N, 13.50. Found: C, 55.34; H, 3.91;
uncorrected. Pre-coated silica gel plates (silica gel 0.25mm, N, 13.76.
60 G F254; Merck, Germany) were used for thin layer chro-
4-(7-Chloroquinolin-4-yl-amino)-N-(3,4-dimethyl-
matography, dichloromethane–methanol (9.5:0.5) mixture isoxazol-5-yl)benzenesulfonamide (6): Yield 88%, melting
was used as a developing solvent system and the spots were point 169.0°C. IR: νmax/cm−1 3380, 3253 (NH), 3057 (CH
visualized by UV light and/or iodine. Infra-red spectra were arom.), 2924, 2840 (CH aliph.), 1609 (C=N), 1375, 1155 (SO2),
1
recorded in KBr discs using IR-470 Shimadzu spectrometer 815 (C–Cl). H-NMR (DMSD-d6, D2O) δ: 2.2, 2.3 (2s, 6H,
(Shimadzu, Tokyo, Japan). NMR spectra (in DMSO-d6) were 2CH3), 7.1, 8.5 (2d, 2H, 2CH pyridine, J=8.1Hz), 7.2–8.3 (m,
recorded on Bruker AC-300 Ultra Shield NMR spectrometer 8H, Ar-H+SO2NH), 10.6 (s, 1H, NHPh, D2O-exchangeable).
(Bruker, Flawil, Switzerland, δ ppm) at 500MHz using TMS 13C-NMR (DMSD-d6) δ: 10.8, 14.6, 103.1, 115.7, 118.2(2),
as internal standard and peak multiplicities are designed as 121.3, 125.3, 125.9, 127.2(2), 127.5, 135.3, 138.9, 143.0, 146.6,
follows: s, singlet; d, doublet; t, triplet; m, multiplet. Elemen- 148.5, 149.7, 159.6, 162.2. Anal. Calcd for C20H17ClN4O3S
tal analyses were performed on Carlo Erba 1108 Elemental (428.89): C, 56.1; H, 4.00; N, 13.06. Found: C, 55.77; H, 3.68;
Analyzer (Heraeus, Hanau, Germany).
General Procedure for the Synthesis of Compounds
N, 13.36.
4-(7-Chloroquinolin-4-yl-amino)-N-(thiazol-5-yl)-
2–14 A mixture of 1 (1.98g, 0.01mol) and the correspond- benzenesulfonamide (7): Yield 90%, melting point 181.6°C.
ing sulfonamide (0.012mol) in dry DMF (20mL) was refluxed IR: νmax/cm−1 3410, 3270 (NH), 3097 (CH arom.), 1616 (C=
1
for 6h. The solid obtained after concentration was filtered and N), 1375, 1141 (SO2), 815 (C–Cl). H-NMR (DMSD-d6, D2O)
crystallized from dioxane to give 2–14.
δ: 6.7, 8.6 (2d, 2H, 2CH pyridine, J=7.7Hz), 6.9–8.3 (m,

56
Vol. 61, No. 1
10H, Ar-H+SO2NH), 10.6 (s, 1H, NHPh, D2O-exchangeable). 15.92. Found: C, 57.60; H, 4.41; N, 15.62.
13C-NMR (DMSD-d6) δ: 115.2, 117.4(2), 118.7, 123.3, 126.3,
4-(7-Chloroquinolin-4-yl-amino)-N-(2,6-dimethoxy-
127.3(2), 127.6, 131.2, 137.8, 144.6, 148.1, 149.8, 152.8, 160.0, pyrimidin-4-yl)benzenesulfonamide (13): Yield 82%, melting
162.2, 168.6. Anal. Calcd for C18H13ClN4O2S2 (416.90): C, point 264.7°C. IR: νmax/cm−1 3370, 3248 (NH), 3066 (CH
51.86; H, 3.14; N, 13.44. Found: C, 51.59; H, 3.52; N, 13.12.
arom.), 2930, 2812 (CH aliph.), 1610 (C=N), 1381, 1134 (SO2),
1
4-(7-Chloroquinolin-4-yl-amino)-N-(1-phenyl-1H-pyrazol-5- 823 (C–Cl). H-NMR (DMSD-d6, D2O) δ: 3.7 (s, 6H, 2OCH3),
yl)benzenesulfonamide (8): Yield 81%, melting point 159.0°C. 5.9 (s, 1H, CH pyrimidine), 6.6, 8.6 (2d, 2H, 2CH pyridine,
IR: νmax/cm−1 3348, 3244 (NH), 3064 (CH arom.), 1615 (C= J=7.5Hz), 7.0–8.3 (m, 7H, Ar-H), 10.2 (s, 1H, NHPh, D2O-
1
N), 1375, 1155 (SO2), 817 (C–Cl). H-NMR (DMSD-d6, D2O) exchangeable), 10.7 (s, 1H, SO2NH, D2O-exchangeable).
δ: 6.6, 8.4 (2d, 2H, 2CH pyridine, J=7.7Hz), 6.8–8.2 (m, 13C-NMR (DMSD-d6) δ: 53.6, 54.3, 84.1, 112.4, 118.6(2), 121.0,
15H, Ar-H+SO2NH), 10.5 (s, 1H, NHPh, D2O-exchangeable). 123.8, 127.2, 129.0(2), 129.3, 133.0, 137.2, 147.8, 148.6, 150.5,
13C-NMR (DMSD-d6) δ: 97.6, 112.5, 118.8(2), 119.0, 122.8, 153.3, 162.2, 163.3, 173.6. Anal. Calcd for C21H18ClN5O4S
125.2, 127.3, 127.9, 128.3(2), 128.8, 133.6, 134.4, 135.3, 136.5, (471.92): C, 53.45; H, 3.84; N, 14.84. Found: C, 53.21; H, 3.63;
139.5, 141.7, 144.7, 146.5, 148.9, 151.5, 153.1. Anal. Calcd for N, 14.66.
C24H18ClN5O2S (475.95): C, 60.56; H, 3.81; N, 14.71. Found: C,
60.22; H, 3.57; N, 14.44.
4-(7-Chloroquinolin-4-yl-amino)-N-(5,6-dimethoxy-
pyrimidin-4-yl)benzenesulfonamide (14): Yield 77%, melt-
4-(7-Chloroquinolin-4-yl-amino)-N-(pyridin-2-yl)- ing point 183.6°C. IR: νmax/cm−1 3340, 3248 (NH), 3070 (CH
benzenesulfonamide (9): Yield 87%, melting point 205.6°C. arom.), 2940, 2831 (CH aliph.), 1375, 1159 (SO2), 821 (C–Cl).
IR: νmax/cm−1 3420, 3232 (NH), 3057 (CH arom.), 1635 (C= 1H-NMR (DMSD-d6, D2O) δ: 3.7 (s, 6H, 2OCH3), 6.6, 8.4 (2d,
1
N), 1394, 1138 (SO2), 773 (C–Cl). H-NMR (DMSD-d6, D2O) 2H, 2CH pyridine, J=7.2Hz), 7.0–8.3 (m, 8H, Ar-H), 9.5 (s,
δ: 6.9, 8.6 (2d, 2H, 2CH pyridine, J=7.8Hz), 7.0–8.3 (m, 11H, 1H, NHPh, D2O-exchangeable), 12.3 (s, 1H, SO2NH, D2O-ex-
Ar-H), 10.6 (s, 1H, NHPh, D2O-exchangeable), 12.1 (s, 1H, changeable). 13C-NMR (DMSD-d6) δ: 58.9(2), 113.9, 119.2(2),
SO2NH, D2O-exchangeable). 13C-NMR (DMSD-d6) δ: 108.2, 120.0, 123.4, 127.6, 129.0(2), 129.2, 129.7, 133.6, 134.2,
114.0, 115.5, 117.4(2), 118.7, 125.2, 127.8, 128.1(2), 128.2, 145.1, 146.9, 149.4, 150.6, 151.8, 157.9, 161.4. Anal. Calcd for
128.8, 136.6, 142.5, 143.2, 146.0(2), 148.7, 149.2, 153.1. Anal. C21H18ClN5O4S (471.92): C, 53.67; H, 3.84; N, 14.84. Found: C,
Calcd for C20H15ClN4O2S (410.88): C, 58.46; H, 3.68; N, 13.64. 53.45; H, 3.51; N, 14.49.
Found: C, 58.77; H, 3.46; N, 13.96.
4-(7-Chloroquinolin-4-yl-amino)-N-(phenylcarbamoyl)-
4-(7-Chloroquinolin-4-yl-amino)-N-(pyrimidin-2-yl)- benzenesulfonamide (15) A mixture of 2 (3.3g, 0.01mol)
benzenesulfonamide (10): Yield 89%, melting point 174.6°C. and phenyl isocyanate (1.21g, 0.01mol) in dry DMF (20mL)
IR: νmax/cm−1 3448, 3390 (NH), 3057 (CH arom.), 1637 (C= containing anhydrous K2CO3 (1g) was refluxed for 14h.
1
N), 1376, 1159 (SO2), 812 (C–Cl). H-NMR (DMSD-d6, D2O) The obtained solid was filtered and crystallized from diox-
δ: 6.6, 8.6 (2d, 2H, 2CH pyridine, J=7.3Hz), 7.0–8.5 (m, 10H, ane. Yield 88%, melting point 159.8°C, IR: νmax/cm−1 3340,
Ar-H), 10.6 (s, 1H, NHPh, D2O-exchangeable), 11.9 (s, 1H, 3280, 3186 (NH), 3055 (CH arom.), 1660 (C=O), 1620 (C=
1
SO2NH, D2O-exchangeable). 13C-NMR (DMSD-d6) δ: 108.4, N), 1373, 1172 (SO2), 744 (C–Cl). H-NMR (DMSD-d6, D2O)
112.1, 118.6(2), 121.8, 123.7, 127.1, 128.9(2), 129.2, 129.7, 135.1, δ: 6.6, 8.2 (2d, 2H, 2CH pyridine, J=7.1Hz), 7.0–8.3 (m, 12
144.5, 147.6, 150.3, 153.0, 158.3(2), 162.2. Anal. Calcd for H, Ar-H), 8.4 (s, 1H, NHCO, D2O exchangeable), 10.2 (s,
C19H14ClN5O2S (411.86): C, 55.41; H, 3.43; N, 17.00. Found: C, 1H, NHPh, D2O-exchangeable) 12.8 (s, 1H, SO2NH, D2O
55.71; H, 3.11; N, 17.37.
exchangeable). 13C-NMR (DMSD-d6) δ: 112.4, 117.2(2), 117.7,
4-(7-Chloroquinolin-4-yl-amino)-N-(4-methyl-pyrimidin-2- 121.0 (2), 121.7, 125.4, 127.3, 127.9 (2), 128.7 (2), 129.0, 129.6,
yl)benzenesulfonamide (11): Yield 87%, melting point 136.7, 139.0, 140.3, 141.3, 142.9, 151.7, 159.6. Anal. Calcd for
164.0°C. IR: νmax/cm−1 3415, 3310 (NH), 3080 (CH arom.), C22H17ClN4O3S (452.91): C, 58.34; H, 3.78; N, 12.37. Found: C,
2940, 2866 (CH aliph.), 1618 (C=N), 1340, 1157 (SO2), 817 58.70; H, 3.49; N, 12.61.
1
(C–Cl). H-NMR (DMSD-d6, D2O) δ: 2.2 (s, 3H, CH3), 6.6,
4-Amino-N-(7-chloroquinolin-4-yl)benzenesulfonamide
8.6 (2d, 2H, 2CH pyridine, J=7.4Hz), 7.0–8.3 (m, 9H, Ar-H), (16) A mixture of 1 (1.98g, 0.01mol) and sulfanilamide
10.5 (s, 1H, NHPh, D2O-exchangeable), 11.8 (s, 1H, SO2NH, (1.72g, 0.01mol) in dry DMF (20mL) containing anhydrous
D2O-exchangeable). 13C-NMR (DMSD-d6) δ: 23.3, 111.9, K2CO3 (1g) was refluxed for 6h. The reaction mixture was
115.3, 118.3(2), 120.7, 124.7, 127.2, 129.1(2), 129.5, 130.0, 135.0, poured onto ice/water and the obtained solid was crystallized
145.8, 148.8, 149.1, 152.9, 157.4, 162.2, 168.2. Anal. Calcd for from ethanol. Yield 94%, melting point 155.9°C, IR: νmax
/
C20H16ClN5O2S (425.89): C, 56.40; H, 3.79; N, 16.44. Found: cm−1 3454, 3389, 3244 (NH, NH2), 3050 (CH arom.), 1627
1
C, 56.12; H, 3.49; N, 16.16.
(C=N), 1363, 1136 (SO2), 808 (C–Cl). H-NMR (DMSD-d6,
4-(7-Chloroquinolin-4-yl-amino)-N-(4,6-dimethyl- D2O) δ: 5.7 (s, 2H, NH2, D2O exchangeable), 6.5, 8.6 (2d, 2H,
pyrimidin-2-yl)benzenesulfonamide (12): Yield 79%, melting 2CH pyridine, J=7.0Hz), 7.0–8.3 (m, 8 H, Ar-H+SO2NH).
point 176.7°C. IR: νmax/cm−1 3448, 3395 (NH), 3086 (CH 13C-NMR (DMSD-d6) δ: 112.5, 117.8 (2), 119.6, 124.7, 127.2,
arom.), 2924, 2861 (CH aliph.), 1597 (C=N), 1345, 1140 (SO2), 128.6 (2), 129.0, 134.0, 136.2, 147.9, 149.3, 151.7, 153.0. Anal.
1
866 (C–Cl). H-NMR (DMSD-d6, D2O) δ: 2.2 (s, 6H, 2CH3), Calcd for C15H12ClN3O2S (333.79): C, 53.97; H, 3.62; N, 12.59.
6.6, 8.6 (2d, 2H, 2CH pyridine, J=7.3Hz), 7.0–8.5 (m, 8H, Found: C, 53.68; H, 3.41; N, 12.31.
Ar-H), 10.3 (s, 1H, NHPh, D2O-exchangeable), 11.9 (s, 1H,
N-(7- Chloroquinolin- 4 -yl)- 4 -(3-phenylureido)-
SO2NH, D2O-exchangeable). 13C-NMR (DMSD-d6) δ: 22.8, benzenesulfonamide (17) A mixture of 16 (3.33g, 0.01mol)
23.0, 104.0, 113.4, 117.4(2), 119.8, 125.9, 127.2, 129.2, 129.3(2), and phenyl isocyanate (1.21g, 0.01mol) in dry DMF (20mL)
129.8, 130.2, 135.0, 144.1, 147.6, 150.3, 156.3, 162.2(2), 167.3. was heated under reflux for 10h. The obtained solid was
Anal. Calcd for C21H18ClN5O2S (439.92): C, 57.33; H, 4.12; N, crystallized from DMF. Yield 79%, melting point 194.0°C,

January 2013
57
IR: νmax/cm−1 3375, 3224 (NH), 3066 (CH arom.), 1678 (C= 116.7 (2), 124.0, 126.1 (2), 126.3, 126.9, 127.4, 128.1, 134.0,
O), 1618 (C=N), 1376, 1132 (SO2), 808 (C–Cl). 1H-NMR 148.3, 150.7, 152.3, 157.6, 158.4, 159.1, 163.9. Anal. Calcd for
(DMSD-d6, D2O) δ: 6.9, 8.4 (2d, 2H, 2CH pyridine, J=7.2Hz), C21H18ClN5O3S2 (487.98): C, 51.69; H, 3.72; N, 14.35. Found:
7.0–8.3 (m, 13 H, Ar-H+SO2NH), 9.1, 9.2 (2s, 2H, 2NH, D2O C, 51.96; H, 3.48; N, 14.10.
exchangeable). 13C-NMR (DMSD-d6) δ: 117.3, 120.0, 121.7 (2),
(E)-N′-(7-Chloroquinolin-4-yl)-N-(4-(N-thiazol-5-
122.8, 124.5 (2), 126.7, 127.5, 128.7 (2), 129.0 (2), 129.4, 134.2, ylsulfamoyl)phenyl)carbamimidothioic Acid (22): Yield 80%,
139.3, 139.8, 148.4, 151.3, 151.8, 152.5, 162.2. Anal. Calcd for melting point 158.5°C, IR: νmax/cm−1 3400, 3370 (NH), 3100
C22H17ClN4O3S (452.91): C, 58.34; H, 3.78; N, 12.37. Found: C, (CH arom.), 1595 (C=N), 1389, 1138 (SO2), 823 (C–Cl).
58.72; H, 3.55; N, 12.18.
1H-NMR (DMSD-d6, D2O) δ: 2.3 (s, 1H, SH, D2O exchange-
7-Chloro-4-isothiocyanatoquinoline (18) A mixture of 1 able), 6.7, 8.6 (2d, 2H, 2CH pyridine, J=6.9Hz), 7.0–8.1 (m,
(1.98g, 0.01mol) and ammonium thiocyanate (1.52g, 0.02mol) 10 H, Ar-H+NH), 8.8 (s, 1H, SO2NH, D2O exchangeable).
in dry acetone (20mL) was refluxed for 1h. The reaction 13C-NMR (DMSD-d6) δ: 112.4, 116.6 (2), 119.7, 124.0, 125.1
mixture was cooled, poured onto ice/water and the obtained (2), 126.6, 127.0, 127.7, 127.8, 136.9, 141.1, 145.3, 147.8, 152.2,
solid was crystallized from ethanol to give 18 (mp and mpp 155.0, 160.0, 168.7. Anal. Calcd for C19H14ClN5O2S3 (475.99):
as reported). Yield 94%, melting point 114.7°C, IR: νmax/cm−1 C, 47.94; H, 2.96; N, 14.71. Found: C, 47.63; H, 2.77; N, 15.08.
1
2072 (N=C=S), 1615 (C=N), 879 (C–Cl). H-NMR (DMSD-
(E)-N′-(7-Chloroquinolin-4-yl)-N-(4-(N-pyridin-2-
d6, D2O) δ: 6.9, 8.9 (2d, 2H, 2CH pyridine, J=6.8Hz), 7.2–8.4 ylsulfamoyl)phenyl)carbamimidothioic Acid (23): Yield 86%,
(m, 3H, Ar-H). 13C-NMR (DMSD-d6) δ: 118.8, 126.6, 127.7, melting point 150.3°C, IR: νmax/cm−1 3350, 3215 (NH), 3057
129.8, 130.6, 136.4, 138.9, 140.4, 150.9, 152.0. Anal. Calcd for (CH arom.), 1629 (C=N), 1394, 1134 (SO2), 817 (C–Cl).
C10H5ClN2S (220.68): C, 54.43; H, 2.28; N, 12.69. Found: C, 1H-NMR (DMSD-d6, D2O) δ: 2.5 (s, 1H, SH, D2O exchange-
54.67; H, 2.60; N, 12.44.
able), 6.7, 8.5 (2d, 2H, 2CH pyridine, J=7.4Hz), 6.8–8.1
General Procedure for the Synthesis of Carbamimido- (m, 12 H, Ar-H+NH), 8.9 (s, 1H, SO2NH, D2O exchange-
thioic Acid Derivatives 19–25 A mixture of 18 (2.20g, able). 13C-NMR (DMSD-d6) δ: 112.1, 113.4, 115.6, 118.7 (2),
0.01mol) and the appropriate sulfonamide (0.012mol) in dry 124.4, 127.6 (2), 127.8, 128.3, 128.5, 128.8, 138.6, 140.1,
DMF (30mL) containing a catalytic amount of triethylamine 146.8, 151.9, 152.2, 152.7, 152.9, 154.4, 160.1. Anal. Calcd for
was heated under reflux for 18h. The obtained solid was C21H16ClN5O2S2 (469.97): C, 53.67; H, 3.43; N, 14.90. Found:
filtered and crystallized from ethanol to give 19–25, respec- C, 53.44; H, 3.10; N, 14.68.
tively.
(E)-N′-(7-Chloroquinolin-4-yl)-N-(4-(N-pyrimidin-2-
(E)-N′-(7-Chloroquinolin-4-yl)-N-(4-sulfamoylphenyl)- ylsulfamoyl)phenyl)carbamimidothioic Acid (24): Yield 88%,
carbamimidothioic Acid (19): Yield 79%, melting point melting point 207.9°C, IR: νmax/cm−1 3431, 3390 (NH), 3085
260.4°C, IR: νmax/cm−1 3387, 3260, 3200 (NH, NH2), 3095 (CH (CH arom.), 1620 (C=N), 1340, 1155 (SO2), 815 (C–Cl).
1
arom.), 1612 (C=N), 1329, 1155 (SO2), 815 (C–Cl). H-NMR 1H-NMR (DMSD-d6 D2O) δ: 2.3 (s, 1H, SH, D2O exchange-
(DMSD-d6, D2O) δ: 2.5 (s, 1H, SH, D2O exchangeable), able), 6.7, 8.5 (2d, 2H, 2CH pyridine, J=7.0Hz), 6.8–8.3 (m,
6.5, 8.6 (2d, 2H, 2CH pyridine, J=6.7Hz), 7.2–8.1 (m, 8 H, 11 H, Ar-H+NH), 8.7 (s, 1H, SO2NH, D2O exchangeable).
Ar-H+NH), 8.4 (s, 2H, SO2NH2, D2O exchangeable) 13C-NMR 13C-NMR (DMSD-d6) δ: 112.1, 115.4, 118.5 (2), 124.8, 127.6
(DMSD-d6) δ: 115.7, 119.0, 123.3, 126.8 (2), 126.9, 127.0, (2), 128.5, 129.3, 129.7, 137.9, 140.9, 153.0, 154.6, 157.2, 158.3
127.2, 127.9, 132.1, 138.7, 144.7, 151.3, 152.3, 156.0, 165.3. (2), 161.9, 168.3. Anal. Calcd for C20H15ClN6O2S2 (470.96): C,
Anal. Calcd for C16H13ClN4O2S2 (392.88): C, 48.91; H, 3.34; N, 51.01; H, 3.21; N, 17.84. Found: C, 51.34; H, 3.55; N, 17.56.
14.26. Found: C, 48.66; H, 3.60; N, 14.59.
( E ) - N ′- ( 7- C h l o r o q u i n o l i n - 4 -y l ) - N - (4 - ( N - (4 -
( E ) - N ′- ( 7- C h l o r o q u i n o l i n - 4 -y l ) - N - (4 - ( N - (3 - methylpyrimidin-2-yl)sulfamoyl)phenyl)carbamimidothioic
methylisoxazol-5-yl)sulfamoyl)phenyl)carbamimidothioic Acid Acid (25): Yield 84%, melting point 224.9°C, IR: νmax
/
(20): Yield 77%, melting point 189.0°C, IR: νmax/cm−1 3348, cm−1 3350, 3210 (NH), 3065 (CH arom.), 2940, 2860 (CH
1
3290 (NH), 3095 (CH arom.), 2970, 2865 (CH aliph.), 1616 aliph.), 1610 (C=N), 1375, 1151 (SO2), 829 (C–Cl). H-NMR
1
(C=N), 1375, 1161 (SO2), 821 (C–Cl). H-NMR (DMSD-d6, (DMSD-d6, D2O) δ: 2.2 (s, 3H, CH3), 2.3 (s, 1H, SH, D2O
D2O) δ: 2.2 (s, 1H, SH, D2O exchangeable), 2.3 (s, 3H, CH3), exchangeable), 6.6, 8.2 (2d, 2H, 2CH pyridine, J=6.7Hz),
6.1 (s, 1H, CH isoxazole), 6.6, 8.6 (2d, 2H, 2CH pyridine, 6.7–8.1 (m, 10H, Ar-H+NH), 8.6 (s, 1H, SO2NH, D2O ex-
J=7.0Hz), 7.2–8.3 (m, 8 H, Ar-H+NH), 8.7 (s, 1H, SO2NH, changeable). 13C-NMR (DMSD-d6) δ: 22.8, 111.8, 113.7, 116.2
D2O exchangeable). 13C-NMR (DMSD-d6) δ: 12.0, 102.5, (2), 118.8, 124.8 (2), 125.5, 127.1, 127.6, 129.3, 134.1, 143.1,
115.8, 118.2 (2), 123.7, 126.6 (2), 127.5, 128.0, 128.4, 128.7, 145.6, 152.8, 154.9, 156.2, 156.6, 160.1, 167.2 . Anal. Calcd for
138.1, 144.3, 146.9, 153.2, 157.9, 160.2, 162.2, 169.5. Anal. C21H17ClN6O2S2 (484.98): C, 52.01; H, 3.53; N, 17.33. Found:
Calcd for C20H16ClN5O3S2 (473.96): C, 50.68; H, 3.40; N, C, 51.73; H, 3.36; N, 17.68.
14.78. Found: C, 50.40; H, 3.12; N, 14.98.
Molecular Docking All the molecular modeling studies
(E ) - N′- (7- C h lo r o q u i n ol i n - 4 -yl) - N - (4 - (N - (3, 4 - were carried out on an Intel Pentium 1.6GHz processor, 512
dimethylisoxazol-5-yl)sulfamoyl)phenyl)carbamimidothioic MB memory with Windows XP operating system using Mo-
Acid (21): Yield 79%, melting point 182.2°C, IR: νmax
/
lecular Operating Environment (MOE, 10.2008) software. All
cm−1 3348, 3215 (NH), 3085 (CH arom.),, 2966, 2842 (CH the minimizations were performed with MOE until a RMSD
1
aliph.), 1620 (C=N), 1375, 1155 (SO2), 819 (C–Cl). H-NMR gradient of 0.05kcalmol−1 Å−1with MMFF94X force field and
(DMSD-d6, D2O) δ: 2.1 (s, 1H, SH, D2O exchangeable), 2.2, the partial charges were automatically calculated. The X-ray
2.3 (2s, 6H, 2CH3), 6.7, 8.6 (2d, 2H, 2CH pyridine, J=6.9Hz), crystallographic structure of PI3K complexe with its ligand
7.0–8.1 (m, 8 H, Ar-H+NH), 8.9 (s, 1H, SO2NH, D2O ex- (PDB ID: 3S2A) was obtained from the protein data bank.
changeable). 13C-NMR (DMSD-d6) δ: 9.2, 13.2, 102.6, 115.2, The enzyme was prepared for docking studies where: (i)

58
Vol. 61, No. 1
541–546 (1997).
Ligand molecule was removed from the enzyme active site.
(ii) Hydrogen atoms were added to the structure with their
standard geometry. (iii) MOE Alpha Site Finder was used for
the active sites search in the enzyme structure and dummy
atoms were created from the obtained alpha spheres. (iv) The
obtained model was then used in predicting the ligand en-
zymes interactions at the active site
6) Kobayash J., Cheng J., Nakamura H., Ohizumi Y., Hirata Y., Sasaki
T., Ohta T., Nozoe S., Tetrahedron Lett., 29, 1177–1180 (1988).
7) Utsugi T., Aoyagi K., Asao T., Okazaki S., Aoyagi Y., Sano M.,
Wierzba K., Yamada Y., Jpn. J. Cancer Res., 88, 992–1002 (1997).
8) Jonckers T. H., van Miert S., Cimanga K., Bailly C., Colson P., De
Pauw-Gillet M. C., van den Heuvel H., Claeys M., Lemière F., Es-
mans E. L., Rozenski J., Quirijnen L., Maes L., Dommisse R., Le-
mière G. L., Vlietinck A., Pieters L., J. Med. Chem., 45, 3497–3508
(2002).
9) Peczyńska-Czoch W., Pognan F., Kaczmarek L., Boratyński J., J.
Med. Chem., 37, 3503–3510 (1994).
10) Drews J., Science, 287, 1960–1964 (2000).
11) Supuran C. T., Scozzafava A., Curr. Med. Chem. Immunol. Endocr.
Metab. Agents, 1, 61–97 (2001).
12) Maren T. H., Annu. Rev. Pharmacol. Toxicol., 16, 309–327 (1976).
13) Boyd A. E. 3rd, Diabetes, 37, 847–850 (1988).
14) Thornber C. W., Chem. Soc. Rev., 8, 563–580 (1979).
15) Casini A., Scozzafava A., Mastrolorenzo A., Supuran L. T., Curr.
Cancer Drug Targets, 2, 55–75 (2002).
16) Supuran C. T., Nat. Rev. Drug Discov., 7, 168–181 (2008).
17) Supuran C. T., Scozzafava A., Bioorg. Med. Chem., 15, 4336–4350
(2007).
18) Supuran C. T., Scozzafava A., Casini A., Med. Res. Rev., 23, 146–
189 (2003).
19) Knight S. D., Schmidt S. J., Smithkline beecham corporation, US
Patent: US 8138347 (2008).
20) Ghorab M. M., Ragab F. A., Noaman E., Heiba H. I., El-Hossary E.
M., Arzneimittelforschung, 57, 795–803 (2007).
21) Ghorab M. M., Ragab F. A., Noaman E., Heiba H. I., El-Hossary E.
M., Arzneimittelforschung, 58, 35–41 (2008).
22) Hogle M. B., Shelar A. R., Kachare D. S., Salunkhe V. K., J. Indian
Chem. Soc., 64, 314–316 (1987).
Biological Screening. In Vitro Antitumor Activity
Human breast cancer cell line (MDA-MB231), skin cancer
cell line (HT 1080) and neuroblastoma cell line (SH-SY5Y)
were used in this study. The cytotoxic activity was measured
in vitro for the newly synthesized compounds using the Sulfo-
Rhodamine-B stain (SRB) assay using the method of Skehan
et al.31) The in vitro anticancer screening was done by the
pharmacology unit at Pharmacognosy Department, College of
Pharmacy, King Saud University, Riyadh, Saudi Arabia.
Cells were plated in 96-multiwell plate (104 cells/well) for
24h before treatment with the compound(s) to allow attach-
ment of cell to the wall of the plate. Test compounds were
dissolved in dimethyl sulfoxide. Different concentrations of
the compound under test (5, 12.5, 25, 50µm) were added to the
cell monolayer. Triplicate wells were prepared for each indi-
vidual concentration. Monolayer cells were incubated with the
compound(s) for 48h at 37°C and in atmosphere of 5% CO2.
After 48h, cells were fixed, washed and stained for 30min
with 0.4% (wt/vol) SRB dissolved in 1% acetic acid. Excess
unbound dye was removed by four washes with 1% acetic acid
and attached stain was recovered with Trise–ethylenediamine-
tetraacetic acid (EDTA) buffer. Color intensity was measured
in an enzyme-linked immunosorbent assay (ELISA) reader.
The relation between surviving fraction and drug concentra-
tion is plotted to get the survival curve for cancer cell line
after the specified time. The molar concentration required for
50% inhibition of cell viability (IC50) was calculated and com-
pared to the reference drug Doxorubicin (CAS, 25316-40-9)
and the results are given in Table 2.
23) Zhong B., Al-Awar R. S., Shih C., Grimes J. H. Jr., Vieth M., Ham-
douchi C., Tetrahedron Lett., 47, 2161–2164 (2006).
24) Weinstein I. B., Begemann M., Zhou P., Han E. K., Sgambato A.,
Doki Y., Arber N., Ciaparrone M., Yamamoto H., Clin. Cancer Res.,
3, 2696–2702 (1997).
25) Weinstein I. B., Joe A. K., Nat. Clin. Pract. Oncol., 3, 448–457
(2006).
26) Jia S., Liu Z., Zhang S., Liu P., Zhang L., Lee S. H., Zhang J.,
Signoretti S., Loda M., Roberts T. M., Zhao J. J., Nature, 454,
776–779 (2008).
27) Wee S., Wiederschain D., Maira S. M., Loo A., Miller C., deBeau-
mont R., Stegmeier F., Yao Y. M., Lengauer C., Proc. Natl. Acad.
Sci. U.S.A., 105, 13057–13062 (2008).
Acknowledgment This study was supported by the Na-
tional Plan for Science and Technology Program, King Saud
University (Grant 10-MED-1223-02), King Abdulaziz City for
Science and Technology, Riyadh, Saudi Arabia.
28) Crabbe T., Welham M. J., Ward S. G., Trends Biochem. Sci., 32,
450–456 (2007).
29) Kim D., Kim S., Koh H., Yoon S. O., Chung A. S., Cho K. S.,
Chung J., FASEB J., 15, 1953–1962 (2001).
30) Boller D., Schramm A., Doepfner K. T., Shalaby T., von Bueren
A. O., Eggert A., Grotzer M. A., Arcaro A., Clin. Cancer Res., 14,
1172–1181 (2008).
References
1) Gopal M., Shenoy S., Doddamani L. S., J. Photochem. Photobiol. B,
72, 69–78 (2003).
2) Kim Y. H., Shin K. J., Lee T. G., Kim E., Lee M. S., Ryu S. H., Suh
P. G., Biochem. Pharmacol., 69, 1333–1341 (2005).
3) Zhao Y. L., Chen Y. L., Chang F. S., Tzeng C. C., Eur. J. Med.
Chem., 40, 792–797 (2005).
31) Skehan P., Storeng R., Scudiero D., Monks A., McMahon J., Vistica
D., Warren J. T., Bokesch H., Kenney S., Boyd M. R., J. Natl. Can-
cer Inst., 82, 1107–1112 (1990).
4) Wall M. E., Wani M. C., Cook C. E., Palmer K. H., McPhail A. T.,
Sims G. A., J. Am. Chem. Soc., 88, 3888–3890 (1966).
5) Ma Z. Z., Hano Y., Nomura T., Chen Y. J., Heterocycles, 46,