Computer-based ligand design and synthesis of some new sulfonamides bearing Pyrrole or pyrrolopyrimidine moieties having potential antitumor and radioprotective activities

Article abstract of DOI:10.1080/10426500701557104

A series of new Pyrrole and pyrrolo[2,3-d]pyrimidine derivatives (5-15) was designed, synthesized, and biologically evaluated for their in vitro cytotoxic activity. The design of these compounds was based upon the molecular modeling simulation of the fitt

Full text of DOI:10.1080/10426500701557104

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Phosphorus, Sulfur, and Silicon
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Computer-Based Ligand Design
and Synthesis of Some New
Sulfonamides Bearing Pyrrole
or Pyrrolopyrimidine Moieties
Having Potential Antitumor and
Radioprotective Activities
Mostafa M. Ghorab a , Helmy I. Heiba a , Amira I.
Khalil a , Dalal A. Abou El Ella b & Eman Noaman c
a Department of Drug Radiation Research , National
Center for Radiation Research and Technology
(NCRRT) , Nasr City, Cairo, Egypt
b Pharmaceutical Chemistry Department, Faculty of
Pharmacy , Ain Shams University , Abbasseya, Cairo,
Egypt
c Department of Radiation Biology , National Center
for Radiation Research and Technology (NCRRT) ,
Nasr City, Cairo, Egypt
Published online: 20 Feb 2008.
To cite this article: Mostafa M. Ghorab , Helmy I. Heiba , Amira I. Khalil , Dalal A.
Abou El Ella & Eman Noaman (2007) Computer-Based Ligand Design and Synthesis
of Some New Sulfonamides Bearing Pyrrole or Pyrrolopyrimidine Moieties Having
Potential Antitumor and Radioprotective Activities, Phosphorus, Sulfur, and Silicon
and the Related Elements, 183:1, 90-104, DOI: 10.1080/10426500701557104
To link to this article: http://dx.doi.org/10.1080/10426500701557104

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Phosphorus, Sulfur, and Silicon, 183:90–104, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701557104
Computer-Based Ligand Design and Synthesis of Some
New Sulfonamides Bearing Pyrrole or Pyrrolopyrimidine
Moieties Having Potential Antitumor and
Radioprotective Activities
Mostafa M. Ghorab,1 Helmy I. Heiba,1 Amira I. Khalil,1
Dalal A. Abou El Ella,2 and Eman Noaman3
1Department of Drug Radiation Research, National Center for
Radiation Research and Technology (NCRRT), Nasr City, Cairo, Egypt
2Pharmaceutical Chemistry Department, Faculty of Pharmacy, Ain
Shams University, Abbasseya, Cairo, Egypt
3Department of Radiation Biology, National Center for Radiation
Research and Technology (NCRRT), Nasr City, Cairo, Egypt
A series of new Pyrrole and pyrrolo[2,3-d]pyrimidine derivatives (5–15) was de-
signed, synthesized, and biologically evaluated for their in vitro cytotoxic activity.
The design of these compounds was based upon the molecular modeling simulation
of the fitting values and conformational energy values of the best-fitted conformers
to VEGFRTK inhibitors hypothesis. This hypothesis was generated from its corre-
sponding lead compounds using CATALYST software. Some of the newly synthe-
sized compounds 8, 11, 12, and 13 showed interesting cytotoxic activity compared
with Doxorubicin as a reference drug. These results are nearly consistent with the
molecular modeling studies. Moreover, Compound 7 showed significant radiopro-
tective activity.
Keywords Pyrrole; pyrrolo[2,3-d]pyrimidine; molecular modeling studies; synthesis;
tyrosine kinase inhibitors; antitumor and radioprotective activities
INTRODUCTION
In current cancer chemotherapy, several agents with DNA-cleavage
properties, antimitotics, antimetabolites, inhibitors of topoisomerases,
and most recently, signal transduction inhibitors are used as drugs.1
The confluence of two distinct but related activities in the past 10 years
Received 5 May 2007; accepted 5 June 2007.
Address correspondence to Mostafa M. Ghorab, Prof. of Applied Organic Chemistry,
Department of Drug Radiation Research, National Center for Radiation Research and
Technology, P. O. Box 29, Nasr City, Cairo 11371, Egypt. E-mail: mmsghorab@yahoo.
com
90

Sulfonamides with Potential Antitumor Activities
91
has dramatically accelerated efforts towards the discovery and develop-
ment of novel drugs to treat cancer. The first is a rapidly emerging un-
derstanding that a number of distinct tyrosine kinases play important
roles in tumor progression (growth, survival, metastasis, and angiogen-
esis). The second is the discovery that small molecule compounds have
the capacity to potently and selectively inhibit the biochemical func-
tion of tyrosine kinases by competing for ATP binding at the enzyme
catalytic site.
In 1970, Folkman and Kerbel proposed that inhibition of angio-
genesis can prevent tumor growth2,3 Subsequently, it was also recog-
nized, that metastasis can be affected by angiogenesis. For these rea-
sons, inhibitors of angiogenesis are expected to be valuable drugs for
cancer therapy. The cancer cell is characterized by oncogene-derived
tumor expression of pro-angiogenic proteins, such as vascular endothe-
lial growth factor (VEGF), placenta-like growth factor, basic fibrob-
last growth factor (FGF), platelet-derived endothelial growth factor
(PDGF), angiopoietin-2 (Ang-2), hepatocyte growth factor and insulin-
like growth factor (ICF).4 The mentioned pro-angiogenic growth factors
bind to specific receptors that possess receptor tyrosine kinase (RTK)
activity.
It has been reported that sulfonamides constitute an important
class of drugs with several pharmacological activities including
antibacterial5 and antitumor activities.6,7 Also, different series of
pyrroles8 and pyrrolo[2,3-d]pyrimidines were proved to have antitumor
activity via tyrosine kinase inhibition.9−11
On the other hand, the importance of sulfur-containing molecules for
radioprotection has attracted a considerable attention.12 Also, pyrrole
and pyrrolopyrimidine derivatives were known recently to have signif-
icant antioxidant properties and hence a radioprotective activity.9,13
In this investigation, ligand design—based on molecular model-
ing studies for the development of new hits acting as predicted anti-
angiogenesis—is performed. All these previous findings encourage us
for further exploration of novel antitumor agents. This article aims
to design and synthesize a series of sulfonamides bearing pyrrole and
pyrrolo[2,3-d]pyrimidine moieties to be evaluated as antitumor and ra-
dioprotector hit molecules.
MATERIALS AND METHODS
General Considerations
Melting points are uncorrected and were determined on a Stuart
melting point apparatus (Stuart scientific, Redhill, UK). Elemental
analyses (C, H, N) were performed on Perkin-Elmer 2400 analyzer

92
M. M. Ghorab et al.
(Perkin-Elmer, Norwalk, CT, USA) at the Microanalytical Unit of Cairo
University. All compounds were within 0.4% of the theoretical val-
ues. IR spectra (KBr) were measured on (Pye Unicam SP1000 IR spec-
trophotometer, Thermoelectron, Egelbach, Germany). 1H-NMR spectra
were obtained on a Bruker 300 MHZ NMR spectrophotometer (Bruker,
Munich, Germany) in DMSO-d6 as a solvent, using tetramethyl-silane
(TMS) as internal standard. Mass spectra were run on Varian MAT
311-A70ev (Varian, Fort Collins, USA).
Catalyst Molecular Modeling Experiments
All molecular modeling work was performed on Silicon Graphic (SGI),
Fuel workstation (500 MHz, R 14000 ATM processor, 512 MB memory)
using the catalyst package of Molecular Simulation (version 4.8), under
an IRIX 6.8 operating system, at the Faculty of Pharmacy, Ain Shams
University. A generalized vizualizer, confirm, info, HipHop, compare/fit,
force field was used throughout.
Training sets, lead compounds I–VII, were selected .Molecules were
built within the catalyst and conformational models for each compound
were generated automatically using the poling algorithm. This empha-
sizes representative coverage over a 20 Kcal mol−1 energy range above
the estimated global energy minimum and the best searching proce-
dure was chosen. The training molecules with their associated confor-
mational models were submitted to catalysis by using default common
features hypothesis generation by using HipHop commands. The chem-
ical function groups (features) used in this generation step included
hydrophobic aromatic and hydrogen bonding acceptors.
Synthesis
4-(N-(3-methyl-isoxazol-5-yl)-4-(2-oxo-2-phenyl-ethylamino)
benzenesulfonamide (2)
A mixture of sulfamethoxazol 1 (2.5 g, 0.01 mol) and phenacyl bro-
mide (2 g, 0.01 mol) was refluxed in dimethylformamide (30 mL) in
presence of triethylamine (3 drops) for 3 h. The solid obtained was fil-
tered and recrystallized from appropriate solvent (Table I).7 IR (KBr,
cm−1): 3210 (NH), 1676 (C O), 1340, 1170 (SO2). 1H-NMR (DMSO-d6):
δ 2.3 (s, 3H, CH3), 4.8 (d, 2H, CH2), 6.1 (s, 1H, isoxazol-H), 6.7–8.10 (m,
9H, Ar-H), 11.00 (s, 2H, 2NH).
4-(2-Amino-3-cyano-4-phenyl-pyrrol-1-yl)-N-(3-methyl-
isoxazol-5-yl)-benzenesulfonamide (4)
A mixture of compound 2 (3.7 g, 0.01 mol) and malononitrile (0.7 g,
0.01 mol) was refluxed in ethanol (30 mL) containing sodium ethoxide

Sulfonamides with Potential Antitumor Activities
93
TABLE I Physical Data of the Synthesized Compounds (2–15)
Compd.
No.
Solvent
(crystallization)
M.P.
(◦C)
Yield Molecular formula
(%)
(molecular weight)
2
4
5
6
7
Ethanol
Ethanol
Dioxane
Dioxane
Methanol
Ethanol
Ethanol
Ethanol
Ethanol
Dioxane
Ethanol
Ethanol
248–250 (as reported(7)
183–184 (as reported(7)
242–244
)
)
80
75
81
73
75
70
65
72
80
68
85
69
C18H17N3O4S (371)
C21H17N5O3S (419)
C22H18N6O3S (446)
C22H17N5O4S (447)
C23H19N5O4S (461)
262–264
130–132
190–192
210–212
100–102
218–219
125–126
>300
8
C
25H21N5O5S (503)
C27H21N5O5S2 (559)
28H23N5O5S2 (573)
C28H21N5O3S (507)
22H18N6O4S (462)
10
11
12
13
14
15
C
C
C22H18N6O4S (462)
C22H18N6O3 S2 (478)
>300
(0.5 g) for 3 h. The reaction mixture was acidified with diluted HCl. The
solid obtained was recrystallized from appropriate solvent (Table I).7IR
(KBr,cm−1): 3400, 3260, 3180 (NH, NH2), 2200 (C≡N), 1350, 1170 (SO2).
4-(4-Amino-5-phenyl-pyrrolo [2,3-d]pyrimidin-7-yl)-N-(3-
methyl-isoxazol-5-yl)-benzenesulfonamide (5)
A solution of compound 4 (4.2 g, 0.01 mol) in formamide (20 mL) was
refluxed for 5 h; the reaction mixture was cooled, and then poured onto
ice cooled water. The formed solid was recrystallized from appropriate
solvent (Table I). IR (KBr, cm−1): 3350, 3230, 3190 (NH ,NH2), 1580
(C N), 1340, 1155 (SO2). MS (m/z): 446 (M+, 2.85%), 77 (100%).
N-(3-Methyl-isoxazol-5-yl)-4-(4-oxo-5-phenyl-3,4-dihydro-
pyrrolo[2,3-d]pyrimidin-7-yl) benzenesulfonamide (6)
A solution of compound 4 (4.2 g, 0.01 mol) in formic acid (30 mL)
was refluxed for 5 h, the reaction mixture was cooled, poured onto ice
water, the separated solid was recrystallized from appropriate solvent
(Table I). IR (KBr, cm−1): 3190, 3120 (NH), 1650 (C O), 1580 (C N)
and 1350, 1160 (SO2). MS (m/z): 447 (M+,7.75%), 69 (100%).
N-(3-Cyano-1-(4-(N-(3-methylisoxazol-5-yl)sulfamoyl)phenyl)-
4-phenyl-1H-pyrrol-2-yl)acetamide (7)
A solution of 4 (4.2 g, 0.01 mol) in acetic anhydride (20 mL) was re-
fluxed for 1 h, the reaction mixture was then concentrated, the solid sep-
arated was recrystallized from appropriate solvent (Table I). IR (KBr,
cm−1): 3230, 3190 (2NH), 3100 (CH arom.), 2210 (C≡N), 1730 (C O),
1
1350, 1160 (SO2). H-NMR (DMSO-d6): δ 1.8 [s, 3H, CH3], 2.5 [s, 3H,

94
M. M. Ghorab et al.
COCH3], 6.8 [s, 2H, CH pyrrole+CH isoxazole], 7.2–8.7 [m, 11H, Ar-
H+2NH].
N-Acetyl-N-(3-cyano-1-(4-(N-(3-methylisoxazol-5-
yl)sulfamoyl)phenyl)-4-phenyl-1H-pyrrol-2-yl) acetamide (8)
A solution of 4 (4.2 g, 0.01 mol) in acetic anhydride (20 mL) was
refluxed for 10 h, the reaction mixture was then concentrated, the
solid separated was recrystallized from appropriate solvent (Table I).
IR (KBr, cm−1): 3190 (NH), 2200 (C≡N), 1780, 1750 (2C O), 1350, 1160
(SO2). 1H-NMR (DMSO-d6): δ 1.9 [s, 3H, CH3], 2.6 [s, 6H, 2COCH3], 6.8
[s, 1H, CH isoxazole], 7.2–8.6 [m, 11H, Ar-H+CH pyrrole +NH].
4-(3-Cyano-4-phenyl-2-(phenylsulfonamido)-1H-pyrrol-1-yl)-N-
(3-methylisoxazol-5-yl)benzenesulfonamide (10) and
N-(3-Cyano-1-(4-(N-(3-methylisoxazol-5-yl)sulfamoyl)phenyl)-
4-phenyl-1H-pyrrol-2-yl)-4-methylbenzenesulfonamide (11)
A mixture of compound 4 (4.2 g, 0.01 mol) and benzenesulfonylchlo-
ride (1.9 g, 0.01 mol) or toluenesulfonyl chloride (2 g, 0.01 mol) in ben-
zene (20 mL) containing 3 drops of pyridine was refluxed for 8 h. The
reaction mixture was concentrated and then acidified with diluted HCl.
The solid obtained was crystallized from appropriate solvent to give 10
and 11, respectively (Table I). IR (KBr, cm−1) 10: 3442 (2NH), 2206
1
(C≡N), 1332, 1162 (SO2). H-NMR (DMSO-d6) 10: 2.4 [s, 3H, CH3],
6.3 [s, 2H, CH isoxazole+CH pyrrole], 6.9–8.3 [m, 14H, Ar-H], 11.2 [s,
2H, 2NH]. MS (m/z) 10: 558 (M-1,15.1%), 57 (100%), 77 (69.8%). IR
1
(KBr,cm−1) 11: 3426 (2NH), 2220 (C≡N), 1374, 1162 (SO2). H-NMR
(DMSO-d6) 11: 2.5 [s, 6H, 2CH3], 6.3 [s, 1H, CH pyrrole], 7.0–8.2 [m,
14H, Ar-H+CH isoxazole], 9.1 [s, 2H, 2NH].
4-(2-(Benzylideneamino)-3-cyano-4-phenyl-1H-pyrrol-1-yl)-N-
(3-methylisoxazol-5-yl)benzenesulfonamide (12)
A mixture of 4 (4.2 g, 0.01 mol) and benzaldehyde (1.06 g, 0.01 mol)
was refluxed in ethanol (20 ml) for 3 h, the reaction mixture was concen-
trated. The solid separated was recrystallized from appropriate solvent
(Table I). IR (KBr, cm−1): 3230 (NH), 2200 (C≡N), 1600 (C N), 1330,
1162 (SO2). MS (m/z): 507 (M+, 20.4%) , 82 (100%), 77 (28.6%).
4-(3-Cyano-4-phenyl-2-ureido-pyrrol-1-yl)-N-(3-methyl-
isoxazol-5-yl)-benzenesulfonamide (13)
A mixture of 4 (4.2 g, 0.01 mol) and urea (0.6 g, 0.01 mol) in ethanol
(30 mL) containing sodium ethoxide (0.23 g, 0.01 mol) was refluxed for
3 h. The reaction mixture was cooled and acidified with diluted HCl.
The separated crystals were recrystallized from appropriate solvent

Sulfonamides with Potential Antitumor Activities
95
(Table I). IR (KBr, cm−1): 3352, 3226, 3195 (NH, NH2), 2204 (C≡N),
1690 (C O), 1310, 1120 (SO2). MS (m/z): 461 (M-1, 5.59%), 64 (100%).
4-(4-Amino-2-oxo-5-phenyl-1,2-dihydro-pyrrolo[2,3-d]pyrimi-
din-7-yl)-N-(3-methyl-isoxazol-5-yl)-benzenesulfonamide (14)
and 4-(4-Amino-5-phenyl-2-thioxo-1,2-dihydro-pyrrolo[2,3-d]-
pyrimidin-7-yl)-N-(3-methyl-isoxazol-5-yl)-benzenesulfona-
mide (15)
A mixture of 4 (4.2 g, 0.01 mol), urea (0.9 g, 0.015 mol) or thiourea
(1.14 g, 0.015 mol) was fused together at 250◦C in an oil bath for 20 min;
the formed mass was then triturated with ethanol, and the separated
crystals were recrystallized from appropriate solvent give 10 and 11,
respectively. (Table I).
IR (KBr,cm−1) 14: 3480, 3370, 3200 (NH, NH2), 1650 (C O), 1610
(C N), 1340, 1170 (SO2). MS (m/z) 14: 462 (M+, 30%), 92 (100%). IR
(KBr, cm−1) 15: 3450, 3410, 3380, 3230(NH, NH2), 1600 (C N), 1300
(C S), 1320, 1150 (SO2). MS (m/z) 15: 478 (M+, 2.9%), 55 (100%).
Biological Testing
Antitumor Activity
Ehrlich Ascites Carcinoma cells (EAC) were obtained by needle aspi-
ration of ascitic fluid from the preinoculated mice under aseptic condi-
tions. Tumor cells suspension (2.5 × 106 per ml) was prepared in saline.
Tested compounds were prepared by dissolving 10 µmol of the tested
compounds in a mixture of 7 ml DMSO and 3 ml Saline.
In a set of sterile test tubes (200, 100, 75, 50, 50, and 25 µL) of each
tested compound were mixed with 100 µL of tumor cell suspension ,
then completed to 1 mL with saline to obtain a solution of (200, 100,
75, 50, 50, and 25 µL, respectively) for each tested compound. The test
tubes were incubated at 375C for 2 h. Trypan blue exclusion test was
carried out to calculate the percentage of non-viable cells.14 The results
of in vitro cytotoxic activity experiments are presented in Table II.
Radioprotective Activity
This study was conducted to evaluate the potency of compound (7) as
protective agent against γ -irradiation-induced toxicity. Female Swiss
albino mice were injected intraperitoneally with suspension of the
tested compound in carboxy methylcellulose once every other day for
a total of 3 injections during 7 days. Each injection was given 30 min
prior to exposure to a single dose of whole body γ - irradiation at a dose

96
M. M. Ghorab et al.
TABLE II Fit and Energy Values and In Vitro Cytotoxic Activity of
Some Newly Synthesized Compounds
Non viable cells (%)
Concentration (µMol/mL)
Compound
No.
Fit
value
Energy
K/cal−1
IC50∗
(nMol /ml)
200
100
75
50
25
5
6
7
8
10
11
12
13
2.99
2.98
3.65
3.61
3.59
4.31
3.67
3.68
2.92
2.98
5.00
—
7.43
14.91
13.98
10.37
3.09
17.09
4.34
14.19
10.73
4.46
0
0
0
100
0
100
100
100
0
0
0
0
100
0
100
80
70
0
0
0
0
60
0
70
20
25
0
0
0
0
20
0
30
5
5
0
0
—
55
0
0
0
0
0
0
0
0
0
>200
>200
>200
67.5
>200
64.2
75.78
88.5
>200
>200
—
14
15
0
—
100
0
—
75
0
—
64
0
—
20
Vatalanib
Doxorubicin
0.13
—
81.5
∗IC50value which corresponds to the compound concentration causing 50% mortality
in net cells.
level of 6 Gy. Lipid peroxide level (LPx), and Glutathione content (GSH)
were estimated in blood of animals at the end of the experiment.
Chemicals and facilities. All chemicals and reagents were of the
highest grade commercially available. Facilities including animal house
and biochemical equipments have been made available by the National
Center for Radiation Research and Technology (NCRRT), Cairo, Egypt.
Animals. Female Swiss albino mice weighing 25–30 g were used in
this study. Mice were housed at a constant temperature (24 2C◦) with
alternating 12 h light and dark cycles and fed standard laboratory food
and water.
Irradiation. Whole body gamma irradiation was performed at the
NCRRT, Cairo, Egypt, using Gamma cell-40 (Caesium-137 source).
Animals were irradiated at 3 doses, every other day 30 min after in-
jection with compound 7 at dose level of 6 Gy delivered at a dose rate
of 0.86 Gy/min.
Compound
7 dosing. Tested compound was suspended in
caboxymethylcellulose (CMC) and given to mice by intraperitoneal
injection (i.p.) of the maximum tolerated dose (150 mg /kg body weight)
once every other day for a total of 3 injections during 7 days.

Sulfonamides with Potential Antitumor Activities
97
Experimental design. From the beginning of the experiment, mice
were divided into eight groups. All experimental animals were catego-
rized as follows:
1) control: Animals served as untreated control group;
2) CMC: Animals were treated by i.p. injection of Carboxymethylcel-
lulose;
3) Rad.: Animals were subjected to 3 doses; every other day of whole
body γ -irradiation at a dose level of 6 Gy starting from day 10;
4) compound 7: Animals were treated by i.p. injection of suspension
of compound 7 in Carboxymethylcellulose; and
5) compound 7 + Rad: Mice injected i.p. with compound 7 and sub-
jected to whole body γ -irradiation.
Samples collection. Animals were fasted for 16 h prior to each sam-
pling. Samples were collected after 1day post last irradiation dose.
Whole blood was collected by heart puncture after light anesthesia us-
ing heparinized syringes. One part was used for glutathione (GSH) es-
timation. The separated plasma from heparinized blood was used for
the determination of lipid peroxide as malondialdehyde (MDA).
Analytical procedures. Lipid peroxide (Lpx) level in plasma was as-
certained by the formation of MDA and measured as described by Yosh-
ioka et al.15GSH content was determined according to Beutler et al.16
Statistical analysis. Student’s t test17 was used for the evaluation of
the biochemical parameters.
RESULTS
Generation of Vascular Epithelial Growth Factor Receptor
Tyrosine Kinase (VEGFRTK) Inhibitor Hypothesis Using
CATALYST Software
The lead compounds I–VII, which were reported to have selective VEG-
FRTK inhibitory activity8 were used to generate common feature hy-
pothesis of VEGFRTK inhibitor (Figure 1).
The set of conformational models of each structure of the lead com-
pounds was performed and was used to generate the common feature
hypothesis, where 10 hypotheses were generated. The assessment of
the ideal hypothesis among the generated ones indicated that hypothe-
sis ranked number 2 was the ideal one (Figures 2 and 3). Such an ideal
hypothesis encompassed five features namely (Figure 2); 3 hydrophobic
(HP), two hydrogen bonding acceptors (HBA). The constraint distances

98
M. M. Ghorab et al.
FIGURE 1 Structures of selective VEGFRTK inhibitory lead compounds I–
VII used for generation ofcommon feature VEGFRTK inhibitor hypothesis.
and torsion angle were measured (Figure 3). The validation of this ideal
hypothesis is due to the full mapping of all its five features with the lead
compound V (Vatalanib, Figure 4) and most of the other lead com-
pounds. Molecular modeling simulation studies were then conducted
by measuring the compare/fit values, separately, between the confor-
mational models of compounds 5–15 and ideal selective VEGFRTK in-
hibitor hypothesis (Figure 4). The results of the best fitting values, as
well as the conformational energy of the best-fitted conformer with
this hypothesis, are given in Table II. The result of simulation stud-
ies have revealed that compounds 5–15 would be promising active hit
molecules. These findings prompted us to synthesize compounds 5–15
(Schemes 1–2).
FIGURE 2 5 features [3 HP and 2 HBA].

Sulfonamides with Potential Antitumor Activities
99
FIGURE 3 Constraint distances and torsion angle of VEGFRTK inhibitor hy-
pothesis.
Chemistry
In this investigation, a series of new compounds incorporating the Pyr-
role or pyrrolo[2,3-d]pyrimidine moieties attached to sulfonamide moi-
ety (5–15) was designed, synthesized (Schemes 1–3), and biologically
evaluated for their in vitro cytotoxic and radioprotective activities.
Thus, Interaction of sulfamethoxazole 1 with phenacyl bromide
furnished 4-(2-oxo-2-phenyl-ethylamino)-benzenesulfonamide 2, which
upon reaction with malononitrile in ethanol in presence of sodium
ethoxide yielded the pyrrole derivative 47 (Scheme 1).
The pyrrolopyrimidine derivative 5 was obtained by the reaction
of 4 with formamide. The structure of 5 was established through
microanalysis and its IR spectrum, which showed the absence of (C≡N)
band and presence of (NH2) at 3350, 3230 cm−1. The mass spectrum
of compound 5 exhibited a molecular ion peak m/z at 446 (M+, 2.85%)
with a base peak at 77 (Scheme 2).
FIGURE 4 Mapping of VEGFRTK inhibitor hypothesis with Vatalanib and
compound 11.

100
M. M. Ghorab et al.
SCHEME 1
The behavior of compound 4 towards acid derivatives was also inves-
tigated. Thus, heating compound 4 with formic acid caused cyclization
to give pyrrolopyrimidine derivative 6. The IR spectrum of compound 6
showed the absence of (C≡N) band and presence of band at 1650 cm−1
SCHEME 2

Sulfonamides with Potential Antitumor Activities
101
SCHEME 3
(C O). The mass spectrum of compound 6 exhibited a molecular ion
peak m/z at 439 (M+, 7.75%) with a base peak at 69 (Scheme 2).
Reaction of compound 4 with acetic anhydride for 1 hr yielded the
monoacetyl derivative 7 , while 10 hours reaction time, furnished the
diacetyl derivative 8 instead of the expected fused pyrrolopyrimidine 9.
The IR spectrum of compound 7 revealed the presence of (C≡N) band
at 2210 cm−1 and carbonyl group at 1730 cm−1. Also, the IR spectrum
of compound 8 showed the presence of (C≡N) band at 2200 cm−1 and
two carbonyl groups at 1780 and 1750 cm−1. 1H-NMR spectrum of com-
pound 7 exhibited singlet at 2.5 ppm of the acetyl group.
Interaction of compound 4 with benzenesulphonyl chloride or tolue-
nesulphonyl chloride yielded the corresponding pyrrole derivatives 10
and 11, respectively. The structure of compound 10 was confirmed by
its IR spectrum which showed a band at 2206 cm−1 corresponds to the
(C≡N) group. The mass spectrum of compound 10 exhibited a molecular
ion peak m/z at 558 (M-1, 15.1%) with a base peak at 57. Also, the IR
spectrum of compound 11 showed the presence of (C≡N) band. 1H-NMR
spectrum of compound 11 revealed singlet at 2.5 ppm for two (CH3).
The benzlidine derivative 12 was obtained in a good yield via the
reaction of compound 4 with benzaldehyde. The IR spectrum showed
the presence of bands at 2200 and 1600 cm−1 corresponds to (C≡N) and
(C N) groups, respectively. Also, mass spectrum of compound 12 exhib-
ited a molecular ion peak m/z at 507 (M+, 20.4%), with a base peak at 82.
When compound 4 was allowed to react with urea in ethanol in the
presence of sodium ethoxide yielded compound 13 via elimination of
ammonia. This was proved by IR spectrum which showed bands at
3352, 3226, 3195 cm−1 (NH, NH2), 2204 cm−1 (C≡N) and 1690 cm−1
(C O). The mass spectrum of compound 13 exhibited a molecular ion
peak m/z at 461 (M-1, 5.59%), with a base peak at 64.
Finally, fusion of compound 4 with urea and/or thiourea gave the
condensed pyrimidine derivatives 14 and 15, respectively. IR spectrum

102
M. M. Ghorab et al.
of compounds 14 and 15 revealed the disappearance of the carbonitrile
function group and presence of band at 1650 cm−1 (C O) for compound
14 and 1250 cm−1 (C S) for compound 15.
Antitumor Activity
Results presented in Table II showed some promising compounds as an-
titumor agents. Compounds 8, 11 were the most potent, while compound
12 showed moderate activity, and compound 13 seems to be the least ac-
tive one. The presence of a cyano group in all these compounds enhances
their antitumor activity since the cyano group has been reported to ex-
hibit antitumor activity.18,19 Compounds 8 and 11 containing diacetyl
group or tolyl group respectively showed the highest in-vitro cytotoxic
activity. While the incorporation of a benzilidine moiety in case of com-
pound 12 and ureido group in compound 13 did not greatly enhance the
antitumor activity.
Radioprotective Activity
Radiation exposure significantly increases lipid peroxidation (LPx),
such increase seems to be due to the result of inactivation of scavenger
enzymes activities induced by reactive oxygen species (ROS). Oxidative
stress occurs in living organisms when the production of ROS exceeds
the ability of organisms to prevent their accumulation.20,21 Such eleva-
tion of LPx is accompanied by decline in GSH content and in the activity
of related antioxidant enzyme SOD. Additionally LPx can be initiated by
hydrogen abstraction from lipid molecules by lipid radiolytic products.
This leads to permeability changes, secondary alteration in membrane
proteins and other sequences.22,23
Effect of Compound 7 and/ or γ-Irradiation on Lipid
Peroxidation and Antioxidant Status
Glutathione Level in Blood (GSH)
As summarized in Table III, a significant depletion in GSH level was
observed in blood of irradiated mice compared to their corresponding
controls. While mice exposed to γ -irradiation and treated with com-
pound 7 showed significant increase of GSH content in blood.
Lipid Peroxidation Content (MDA) in Plasma
As shown in Table III, mice exposed to γ -irradiation showed signifi-
cant elevation in Malonaldialdehyde (MDA) level in plasma compared
with the control values. Treatment with compound 7 prior irradiation

Sulfonamides with Potential Antitumor Activities
103
TABLE III Effect of Compound Administration on Blood
Glutathione (GSH) Content and Plasma Lipid Peroxide
Concentrations (LPx) of Normal and Irradiated Mice
GSH
mg/dl
LPx
µMol/ml
Groups
Control
Mean SE
% change
78.59 5.45
(100%)
78.05 0.79
(100%)
CMC
Mean SE#
75.45 0.28
(96.15%)
80 1.18
(103.9%)
Rad.
Mean SE #
Mean SE #
38.98 1.03∗∗∗
(49.59%)
101.29 0.11∗∗∗
(129.78%)
52.57 4.86
(67.35%)
Compd. 7
Compd. 7+Rad
89.3 9.73
(113.62%)
Mean SE #
Mean SE #
260.5 1.7∗∗∗
(331.47%)
74.86 1.41
(95.9%)
Each value is the mean of six mice SE. # : percentage of change from control
group; ∗significant difference from control at P < 0.05; ∗∗high significance at P <
0.01; ∗∗∗very high significance at P <0.001.; CMC: carboxy methyl cellulose.
exhibited a higher reduction in MDA levels in blood as compared with
irradiated group.
CONCLUSION
The present data showed that some compounds combining both pyrrole
or pyrrolo[2,3-d]pyrimidine and benzenesulfonamide moieties exhib-
ited promising in-vitro cytotoxic activity against (EAC) cell line, Com-
pound 11 showed the highest fit value and highest in vitro cytotoxic
activity when compared with other tested compounds and Doxorubicin
as a reference drug. Additionally, compound 7 has a radical scavenging
effect and can prevent radical generation in mice immediately after ir-
radiation, probably by inhibiting the chain reaction of membrane lipid
peroxidation, which follows thereafter.
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