Synthesis, structural characterization and anticancer evaluation of pyrazole derivatives

Article abstract of DOI:10.1007/s00044-017-2035-2

Abstract: The utility of 4-isothiocyanato-N-(1-phenyl-1H-pyrazol-5-yl)benzene sulfonamide 2 in the synthesis of some novel thiosemicarbazide, carbamothioate,1,3,4-thiadiazole, azomethine, thiourea, bisthiourea and imidazole derivatives is reported. The st

Full text of DOI:10.1007/s00044-017-2035-2

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-017-2035-2
ORIGINAL RESEARCH
Synthesis, structural characterization and anticancer evaluation of
pyrazole derivatives
1 ●
2,3 ●
4 ●
Mohamed S. A. El-Gaby Mustafa M. Ghorab
Zainb H. Ismail
4 ●
4
Soad. M. Abdel-Gawad Hala. M. Aly
Received: 14 September 2015 / Accepted: 16 August 2017
Springer Science+Business Media, LLC 2017
©
Abstract The utility of 4-isothiocyanato-N-(1-phenyl-1H-
pyrazol-5-yl)benzene sulfonamide 2 in the synthesis of
some novel thiosemicarbazide, carbamothioate,1,3,4-thia-
diazole, azomethine, thiourea, bisthiourea and imidazole
derivatives is reported. The structure of the newly synthe-
sized compounds was confirmed on the basis of analytical
and spectral data. Some of the prepared compounds were
evaluated for their in vitro anticancer activity against Ehr-
lich ascites carcinoma cells (EAC). It was found that the
corresponding 2-acetyl-N-(4-(N-(1-phenyl-1H-pyrazol-5-yl)
sulfamoyl)phenyl) hydrazinecarbothioamide 7 with IC50
value (2.14 µg/ml) showed better activity than doxorubicin
with IC50 value (43.6 µg/ml) as reference drug.
synthesized and evaluated for their anticancer activity.
O
S
O
O
S
O
H
N
CSCl2
HCl
H
N
N
NH
2
N
NCS
N
Ph
N
Ph
(
2)
(
1)
●
●
●
Keywords Thiosemicarzides Thioureas 1,3,4-thiadiazole
●
●
sulfaphenazole Imidazole Anticancer activity
Introduction
Graphical Abstract New thiosemicarbazide,carbamothio-
ate,1,3,4-thiadiazole, azomethine, thiourea, bisthiourea and
imidazole derivatives containing pyrazole moiety have been
derivatives of pyrazole are important class of heteroaro-
matic ring system that find extensive use in the pharma-
ceutical industry (Anuta et al. 2014). Pyrazoles are reported
to show antibacterial (Tanitame et al. 2005; Vijesh et al.
2013) antifungal (Sun and Zhou 2015), analgesic (Gokulan
et al. 2012), antidiabetic (Faidallah et al. 2011), antic-
onvulsant (Abdel-Aziz et al. 2009),anti-inflammatory
*
*
Mohamed S. A. El-Gaby
m_elgaby@hotmail.com
(
Alam et al. 2013), antiviral (El-Sabbagh et al. 2009),anti-
tuberculine (Castagnolo et al. 2008), and antimalarial
Sanjay et al. 2006) activities. Several new pyrazole deri-
Mustafa M. Ghorab
mmsghorab@yahoo.com
(
vatives have demonstrated promising anti proliferative and
cytotoxic effects (Dias and Salvador 2012). In addition,
several pyrazole scaffolds have been reported as potent
anticancer agents. A series of 1,5-diphenyl-1H-pyrazole-3-
thiourea derivatives showed important antitumor effect and
are suggested as potent candidates for leukemia, liver and
colon cancer treatment (Koca et al. 2013). Celecoxib, sul-
faphenazole, CDPPB, linazolac, mepiprazole, and rimona-
bant are some of the pyrazole-based drugs available today
in the market (Fig. 1) (Kamel 2015). Sulfonamides are a
1
2
3
Chemistry Department, Faculty of Science, Al-Azhar University at
Assiut, Assiut 71524, Egypt
Pharmacognosy Department, College of Pharmacy, King Saud
University, P.O. Box 2457, Riyadh 11451, Saudi Arabia
Drug Radiation Research Department, National Center for
Radiation Research and Technology, P.O.Box 29, Nasr City,
Cairo, Egypt
4
Chemistry Department, Faculty of Science(Girls), Al-Azhar
University, Nasr City, Cairo, Egypt

Med Chem Res
Fig. 1 Biologically active
pyrazole derivatives
O
S
O
O
S
O
significant class of compounds in medicinal and pharma-
ceutical chemistry with several biological applications
H
N
CSCl
HCl
H
N
2
N
NH
2
N
NCS
N
Ph
N
Ph
(
Tilles 2001; Slatore and Tilles 2004; Brackett et al. 2004;
(
2)
(
1)
Harrison 1994; Eroglu 2008).In view of the above men-
tioned findings and in continuation of our interest in bio-
logically active compounds (Abd El-Gawad et al. 2005; El-
Gaby et al. 2006, 2009; Ismail et al. 2008), we report herein
the synthesis of some novel thiosemicarbazide, carba-
mothioate, 1,3,4-thiadiazole, azomethine, thiourea and
thiophene derivatives containing pyrazole moiety to evalu-
ate their anticancer activity.
Scheme 1 Synthesis of 4-Isothiocyanato-N-(1-phenyl-1H-pyrazol-5-
yl) benzenesulfonamide 2
O
S
O
S
C
RNHNH2
EtOH
H
N
H
N
H
N
N
N
NHR
N
Ph
(
3a,b)
a; R = H
b; R = C H
(2)
3
3
6
5
Results and discussion
Chemistry
O
S
O
S
ROH
H
N
H
N
C OR
N
Ph
Isothiocyanates are useful and widely used building blocks
in the synthesis of nitrogen, sulfur and oxygen heterocycles
and organometallic compounds of academic, pharmaceu-
tical and industrial interest (Sharma 1989). The high elec-
trophilicity and nucleophilicity associated with the carbon
and sulfur atoms, respectively, of the isothiocyanates and
their extended π electron system make them unique pre-
cursors of a large variety of target molecules. Consequently,
many classes of five and six-membered nitrogen and sulfur
heterocycles, either carrying various substituents or fused
with benzo or non-benzo nuclei to interesting polyhetero-
cycles, have been synthesized from isothiocyanates which is
(
4a,b)
4
a; R = CH
3
4b; R = C
H
2
5
Scheme 2 Synthesis of thiosemicarbazide 3 and carbamothioate 4
derivatives
The reaction of isothiocyanate derivative 2 with some
nitrogen and oxygen nucleophiles was investigated. Treat-
ment of isothiocyanate derivative 2 with hydrazine hydrate
in ethanol at room temperature gave the novel thiosemi-
carbazide derivative 3a, (Scheme 2). The structure of 3a
was established by elemental analysis and spectral data.
Mass spectrum of 3a revealed a molecular ion peak at m/z
undoubtedly
a landmark in organosulfur chemistry
(
Mukerjee and Ashare 1991). 4-Isothiocyanato-N-(1-phe-
+
nyl-1H-pyrazol-5-yl)benzenesulfonamide 2 was prepared in
high yield via the reaction of sulfaphenazole 1 with thio-
phosgen at room temperature in the presence of dilute
hydrochloric acid (Ismail et al. 2008), (Scheme 1).
356 (M -hydrazine moiety; 5.4%), and the base peak was
found in the spectrum at m/z 77 which is characteristic for
phenyl group. Similarly, isothiocyanate derivative 2 was
reacted with phenyl hydrazine in refluxing ethanol to give

Med Chem Res
O
S
O
S
C
O
C
O
S
O
H
N
H
N
H
HN NH
HCOOH
H
N
H
N
Ac O
2
N
NH N
CH3
(3a)
N
C
C
H
N
Ph
N
Ph
S
O
(
7)
(5)
-
H O
2
-
H O
2
O
S
O
N
N
H
H
O
S
O
N
N
N
N
N
CH3
H
N
H
N
N
Ph
S
(
3a)
N
N
Ph
S
(8)
O
S
O
S
C
S
C
(
6)
H
N
H
N
H
H
N
PhNCS
ArCHO
N
N
N
NHPh
N
Ph
Scheme 3 Synthesis of 5-amino-1,3,4-thiadiazole derivative 6
(
9)
O
S
O
S
C
thiosemicarbazide derivative 3b. The structure of 3b was
elucidated by elemental analysis and spectral data. Its mass
spectrum revealed a molecular ion peak at m/z 461 (M-
H
N
H
N
H
N
N
CH Ar
N
Ph
(
10a,b)
1
;0.4%) and the base peak was observed in the spectrum at
1
0a, Ar= C H Cl-4
10b, Ar= C H OCH -4
6
4
m/z 150 due to the presence of substituted phenyl thiourea
moiety. Phenylcarbamothioate derivatives 4a, b were
achieved by condensation of isothiocyanate derivative 2
with methanol and ethanol, respectively. The structures of
carbamothioate derivatives 4a, b were confirmed by ana-
lytical and spectral data.
Thiosemicarbazide derivative 3a was exploited as start-
ing material for further functionalization and hetero-
cyclization. The cyclocondensation of thiosemicarbazide
derivative 3a with formic acid under reflux afforded 5-
amino-1,3,4-thiadiazole derivative 6, (Scheme 3). The
structure of 6 was established on the basis of elemental
analysis and spectral data. The formation of thiadiazole
derivative 6 may be proceeded via the initial formation of
formyl intermediate 5 followed by intramolecular cycliza-
tion through loss of water molecule (El-Gaby et al. 2003),
6 4 3
Scheme 4 Synthesis of acetylthiosemicarbazide 7, 1,2-Bis(car-
bothioamide) 9 and azomethine 10 derivatives
O
S
O
S
C
H
N
H
N
H
N
N
R
N
Ph
(
11a-d)
1
1
1
1
1a, R = CH
2
CH
2
CH
3
3
3
1b; R = C
6
6
6
H
4
H
4
OCH
-2
1c, R = C
H
OCH
OH-4
-4
RNH
2
1d; R = C
4
(2)
H
2
N
NH
2
O
S
O
S
C
S
C
O
S
H
N
H
N
H
H
N
H
N
H
N
N
N
N
N
Ph
N
O
Ph
(
Scheme 3).
(12)
Refluxing of thiosemicarbazide derivative 3a in acetic
Scheme 5 Synthesis of 1,3-disubstituted thiourea 11 and bisthiourea
derivatives 12
anhydride furnished acetylthiosemicarbazide derivative 7
and structure 8 was ruled out on the basis of analytical and
spectral data (Scheme 4). 1,2-Bis(carbothioamide) deriva-
tive 9 was obtained by treatment of thiosemicarbazide
derivative 3a with phenyl isothiocyanate in refluxing etha-
nol and in the presence of triethylamine. Mass spectrum
revealed a molecular ion peak at m/z 525 (M+2, 22%) with
and spectral data. In a similar manner, 1,3-disubstituted
thioureas 11b–d were obtained by treatment of iso-
thiocyanate derivatives 2 with aromatic amines in refluxing
dioxane in the presence of triethylamine. Mass spectrum of
11d revealed a molecular ion peak at m/z 465 (10.5%) cor-
responding to the molecular formula C H N O S and the
a base peak at m/z 64 which is characteristic for SO moiety.
2
Condensation of 3a with aromatic aldehydes under reflux in
2
2 19 5 3 2
dioxane in the presence of triethylamine yielded the corre-
base peak was observed in the spectrum at m/z 73. Bis-
thiourea derivative 12 was achieved by condensation of
isothiocyanate derivative 2 with excess of 1,4-phenylene-
diamine. Its mass spectrum revealed a molecular ion peak at
m/z 820 (85%) with base peak at m/z 166.
sponding azomethine derivatives 10a, b. Mass spectrum of
+
1
0a revealed a molecular ion peak at m/z 510 (M , 0.6%)
with a base peak at 75.
Condensation of isothiocyanate derivative 2 with propyl
amine in refluxing dioxane in the presence of triethylamine
furnished 1,3-disubstituted thiourea derivative 11a, (Scheme
The reactivity of isothiocyanate derivative 2 towards
binucleophiles was discussed. Thus, treatment of 1,2-phe-
5). The structure of 11 was confirmed by elemental analysis
nylenediamine with isothiocyanate derivative
2
in

Med Chem Res
NH
2
2
Table 1 In vitro cytotoxic activity of some selected synthesized
compounds:
H
S
C
2
N
O
S
O
NH
H
N
H
N
N
N
N
H
Compd. no.
Non-viable cells (%)
IC50 (µg/ml)
DMF/TEA
N
Ph
Concentration (µg/
ml)
(
13)
-H S
2
100
50
25
N
O
S
O
a
3
6
7
1
a
0
0
0
>100
H
N
N
H
a
N
N
Ph
0
0
0
>100
H
100
0
100
0
95
0
2.14
(
14)
a
OH
NH
5
>100
HO
S
O
S
O
Doxorubicin (reference)
100
55
20
43.6
2
H
(
2)
N
N
N
H
N
H
a
DMF/TEA
N
IC50 > 100 (µg/ml) is considered to be inactive
Ph
N
(
15)
-
H S
carcinoma cells (EAC). Doxorubicin was used as the refer-
ence drug in this study. Table 1 shows the in vitro cytotoxic
activity of the newly synthesized compounds. Some of the
tested compounds exhibited significant activity compared to
doxorubicin. It was found that pyrazole carrying sulfona-
mide, acetyl and thiosemicarbazide moieties in one molecule
7 (with IC50 value = 2.14 µg/ml) exhibited higher anti-cancer
activity than the reference drug (with IC50 value = 43.6 µg/
ml). On the other hand, compounds 3a, 6 and 15 revealed no
activity than that of doxorubicin. It is clear from the present
data that the comparison of the cytotoxicity of the pyrazole
derivatives against EAC cell line (Table 1) has showed that
the cell killing potency follows the order 7 > Doxorubicin >
3a > 6 > 15. The active compound 7 could be considered as
useful templates for further development to obtain more
potent anti-cancer agent.
2
N
O
S
O
H
N
N
N
H
O
COOC
2 5
H
Ph
(
16)
N
C H OOC
2 5
S
NH C NH
NH2
N
Ph
O
S
O
H
N
N
N
DMF/TEA
N
Ph
N
Ph
(
17)
Scheme 6 Synthesis of 2-aminobenzimidazole 14 and thiourea 15, 17
derivatives
dimethylformamide in the presence of triethylamine pro-
duced the 2-amino-benzimidazole derivative 14, (Scheme
). The structure of 14 was supported by analytical and
6
spectral data. Its mass spectrum revealed a molecular ion
peak m/z at 431 (M+1, 6.28%) with a base peak at m/z 69.
The formation of 14 is assumed to proceed via the initial
formation of thiourea intermediate 13 followed by intra-
molecular cyclization (El-Gaby et al. 2002) through loss of
hydrogen sulfide. On the other hand, when isothiocyanate
derivative 2 was reacted with 2-aminophenol in refluxing
dimethylformamide and triethylamine, yielded the thiourea
derivative 15. The formation of benzoxazole derivative 16
was ruled out on the basis of analytical and spectral data.
Mass spectrum displayed a molecular ion peak at m/z
Experimental
Chemistry
All melting points are uncorrected and were determined on a
Stuart melting point apparatus. IR spectra were recorded on a
Shimadzu-440 IR spectrophotometer using the KBr techni-
1
que (Shimadzu, Japan). HNMR spectra were measured on a
BRUKER proton NMR-Avance 300 (300 Hz), in DMSO-d6
as a solvent, using tetramethylsilane as an internal standard.
The mass spectra were performed by HP Model MS-5988.
Elemental analyses were carried out by the Microanalytical
Research Centre, Faculty of Science, Cairo University. All
compounds were within ±0.4% of the theoretical values.
4
65 (0.8%) and the base peak was found in the spectrum at
m/z 73. Ethyl-5-amino-1-phenyl-1H-pyrazole-4-carboxylate
was condensed with isothiocyanate derivative 2 to yield
thiourea derivative 17 on the basis of analytical and spectral
data. Mass spectrum revealed a molecular ion peak at m/z
5
58 [M-29 (C H ); 30%] with a base peak at m/z 73.
2 5
4-Isothiocyanato-N-(1-phenyl-1H-pyrazol-5-yl)
In vitro anticancer evaluation
benzenesulfonamide (2)
Some of the newly synthesized compounds were evaluated
for their in vitro anticancer activity against Ehrlich ascites
Sulfaphenazole 1 (0.01 mol) was dissolved in 100 ml H O
containing 20 ml of concentrated HCl. To this, 0.012 mol of
2

Med Chem Res
CSCl2 was added in one portion. Stirring was begun
immediately and continued until all of the red color of
OCH ), 5.68 (s, 2H, pyrazole-H), 7.32–7.96 (m, 9H, Ar-H),
3
8.9, 9.1 ppm (2s, 2H, 2NH, exchangeable with D O); anal.
2
CSCl disappeared (1 h) and the product was precipitated as
calcd. For C H N O S : C, 52.56; H, 4.15; N, 14.42.
2
17 16 4 3 2
a white crystal. The resulting solid was filtered off, dried
and recrystallized from acetone to give 2 (Ismail et al.
Found: C, 52.30; H, 4.40; N, 14.20.
2
008).
O-Ethyl 4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)phenyl
carbamothioate (4b) Yellowish needles; yield 88%; mp.
168–169 °C; IR (KBr) νmax 3220,3104(2NH), 3038 (CH-
General procedure for the synthesis of
hydrazinecarbothioamide derivatives (3a) and (3b)
−1
arom.), 2986 (CH-aliph.),1594 (C=N), 1384, 1160 cm
1
2 6
(
SO ); H NMR (DMSO-d , 300 MHz,): δ = 1.3 (t, 3H,
Hydrazine hydrate and/or phenyl hydrazine (0.01 mol) was
added to a solution of 2 (0.01 mol) in ethanol 40 ml. The
reaction mixture was stirred for 3 h until it gave a white
precipitate. The products was recrystallized from ethanol to
give 3a, b, respectively.
CH ), 4.5 (q, 2H, CH ), 5.9 (s, 2H, pyrazole-H), 7.4–7.64 (m,
3 2
9H, Ar-H), 10.27, 11.41 ppm (2s, 2H, 2NH, exchangeable
with D O); anal. calcd. For C H N O S : C, 53.71; H,
2
18 18 4 3 2
4.51; N, 13.92. Found: C, 53.40; H, 4.20; N, 13.70.
4
-(1,3,4-Thiadiazol-2-ylamino)-N-(1-phenyl-1H-pyrazol-5-
N-(4-(N-(1-Phenyl-1H-pyrazol-5-yl)sulfamoyl)phenyl)
hydrazinecarbothioamide (3a) white needles; yield 79%;
yl)benzene-sulfonamide (6)
mp. 135–136 °C; IR (KBr) νmax 3356, 3190(NH ), 3068
2
1
−
1
A solution of 3a (0.01 mol) in formic acid 10 ml was
refluxed for 24 h. The reaction mixture was cooled and the
precipitate was filtered and recrystallized from ethanol to
give 6: brownish needles; yield: 85%; mp. 198–199 °C; IR
(
CH-arom.),1628 (C=N), 1338,1160 cm (SO ); H NMR
2
(
DMSO-d , 300 MHz,): δ = 4.80 (s, 2H, NH ,exchangeable
6
2
with D O), 5.60 (s, 2H, pyrazole-H), 7.34–8.20 (m, 10H,
2
Ar-H + NH),10.23,10.80 ppm (2s, 2H, 2NH, exchangeable
+
(
(
KBr) νmax 3417, 3313 (2NH), 2896 (CH-aliph.), 1596
with D O); EIMS m/z 356 (M -hydrazine moiety), 77
2
−
1
1
C=N), 1388, 1157 cm (SO ); H NMR (DMSO-d , 300
(
100); anal. calcd. For C H N O S : C, 49.47; H, 4.15; N,
2
6
1
6 16 6 2 2
MHz,): δ = 5.85 (s, 2H, pyrazole-H), 7.44–8.14 (m, 9H, Ar-
H), 9.1 (s, 1H, thiadiazole-H), 10.03, 10.9 ppm (2s, 2H,
2
1.63. Found: C, 49.20; H, 4.50; N, 21.30.
2
NH, exchangeable with D O); anal. calcd. For
2
-Phenyl-N-(4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)
2
C H N O S : C, 51.24; H, 3.54; N, 21.09. Found: C,
phenyl)hydrazinecarbothio-amide (3b) White crystals;
yield 83%; mp. 138–139 °C; IR (KBr) νmax 3282, 3170
17 14 6 2 2
51.50; H, 3.20; N, 21.30.
−
1
(
(
2NH),3074(CH-arom.), 1627(C=N), 1330, 1161 cm
SO ); H NMR (DMSO-d , 300 MHz,): δ = 5.72 (s, 2H,
1
2-acetyl-N-(4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)
2
6
phenyl)hydrazinecarbothio-amide (7)
pyrazole-H),
7.64–8.10
(m,
15H,
Ar-H + NH),
8
.76,10.20,10.75 ppm (3s, 3H, 3NH, exchangeable with
A solution of 3a (0.01 mol) in acetic anhydride 5 ml was
heated under reflux for 24 h. After cooling, the solid product
thus formed was collected and recrystallized from ethanol to
give 7. Yellowish needles, yield 80%; mp. 146–147 °C; IR
D O); EIMS m/z 461 (M-1), 150 (100); anal. calcd. For C
2
H N O S : C, 56.88; H, 4.34; N, 18.09. Found: C, 56.50;
2 20 6 2 2
2
H, 4.10; N, 18.30.
(
KBr) νmax 3473, 3413 (2NH), 2935 (CH-aliph.), 1732
−
1
1
General procedure for the synthesis of o-substituted-4-(N-
(C═O), 1589 (C=N), 1373, 1172 cm (SO ); H NMR
2
(
1-phenyl-1H-pyrazol-5-yl)sulfamoyl)phenyl
(DMSO-d , 300 MHz,): δ = 2.3 (s, 3H, COCH ), 5.81
6
3
carbamothioate (4a) and (4b)
(2s,2H,pyrazole-H),7.4–7.9(m, 11H, Ar-H + 2NH), 9.7,
0.5 ppm (2s, 2H, 2NH, exchangeable with D O); anal.
1
2
A solution of 2 (0.01 mol) in methanol and/or ethanol 30 ml
was heated under reflux for 1 h. The solid obtained was
collected by filtration and recrystallized from dioxane to
give 4a, b, respectively.
calcd. For C H N O S : C, 50.22; H, 4.21; N, 19.52.
18 18 6 3 2
Found: C, 50.50; H, 4.40; N, 19.20.
1
2
N -phenyl-N -(4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)
phenyl)hydra-zine-1,2-bis (carbothioamide) (9)
O-Methyl 4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)phe-
nyl carbamothioate (4a) Orange needles; yield 90%; mp.
A mixture of 3a (0.01 mol) and phenylisothiocyanate (0.01
mol), in ethanol 20 ml containing three drops of triethyla-
mine was heated under reflux for 3 h and then cooled,
poured into crushed ice water, the obtained solid was
1
02–103 °C; IR (KBr) νmax 3380, 3200 (2NH), 3055 (CH-
−
1
arom.), 2927 (CH-aliph.), 1654 (C=N), 1384, 1153 cm
1
(
SO ); H NMR (DMSO-d , 300 MHz,): δ = 3.98 (s, 3H,
2
6

Med Chem Res
recrystallized from dioxane to give 9. White needles; yield
N-(1-phenyl-1H-pyrazol-5-yl)-4-(3-propylthioureido)ben-
zenesulfonamide (11a) Yellow needles; yield 75%; mp.
9
2
0%; mp. 108–109 °C; IR (KBr) νmax 3348, 3228 (2NH),
−
1
1
947 (CH-aliph.), 1620 (C=N), 1315, 1134 cm (SO ); H
102–103 °C; IR (KBr) νmax 3360, 3254 (NH ), 3076 (CH-
2
2
−
1
NMR (DMSO-d , 300 MHz,): δ = 6.2 (s, 2H, pyrazole-H),
arom.), 2962 (CH-aliph.), 1594 (C=N) 1330, 1128 cm
(SO ); H NMR (DMSO-d , 300 MHz,): δ = 0.95 (t, 3H,
2 6
6
,
1
7
.27–7.58 (m, 16H, Ar-H + 2NH), 7.95, 8.60, 10.8 ppm
(
3s, 3H, 3NH, exchangeable with D O); EIMS m/z 525 (M
CH ), 1.2 (t, 2H, CH ), 1.6 (m, 2H, CH ), 5.42 (s, 2H,
2
3 2 2
+
2), 64 (100); anal. calcd. For C H N O S : C, 52.75;
pyrazole-H), 7.0–7.98 (m, 11H, Ar-H + 2NH), 9.45 ppm (s,
2
3
21
7
2
3
H, 4.04; N, 18.72. Found: C, 52.40; H, 4.20; N, 18.40.
1H, NH, exchangeable with D O); anal. calcd. For
2
C H N O S : C, 54.92; H, 5.09; N, 16.85. Found: C,
1
9
21
5
2
2
General procedure for the synthesis of 2-(4-substituded-
benzylidene)-N-(4-(N-(1-phenyl-1H-pyrazol-5-yl)sulfamoyl)-
phenyl)hydrazinecarbothioamide (10a) and (10b)
54.60; H, 5.30; N, 16.60.
4-(3-(2-methoxyphenyl)thioureido)-N-(1-phenyl-1H-pyra-
zol-5-yl)benzenesulfonamide (11b) Reddish crystals; yield
90%; mp. 78–80 °C; IR (KBr) νmax 3380, 3280 (2NH), 3004
Equimolar amounts of 3a (0.01 mol) and the appropriate 4-
chloro-benzaldehyde and/or p-anisaldehyde (0.01 mol) in
dimethylformamide 10 ml were treated with a few drops of
triethylamine and refluxed for 4 h, cooled, poured on to ice
water and acidified with dil. HCl; the resulting solid was
filtered off and recrystallized from ethanol to give 10a, b,
respectively.
(CH-arom.), 2962 (CH-aliph.), 1593 (C=N) 1334, 1161
,
−1
1
cm (SO ); H NMR (DMSO-d , 300 MHz,): δ = 3.8 (s,
2
6
3H, OCH ), 5.8 (s, 2H, pyrazole-H), 6.9–7.8 (m, 13H, Ar-H)
3
and 9.5, 10.4, 10.6 ppm (3s, 3H, 3NH, exchangeable with
D O); anal. calcd. For C H N O S : C, 57.60; H, 4.41; N,
2
23 21
5
3
2
14.60. Found: C, 57.30; H, 4.20; N, 14.40.
2
-(4-Chlorobenzylidene)-N-(4-(N-(1-phenyl-1H-pyrazol-5-
4-(3-(4-methoxyphenyl)thioureido)-N-(1-phenyl-1H-pyra-
zol-5-yl)benzenesulfonamide (11c) Yellowish crystals;
yield 79%; mp. 98–99 °C; IR (KBr) νmax 3282, 3209, 3136
yl)sulfamoyl)-phenyl)- hydrazinecarbothioamide (10a)
Yellow solid; yield 78%; mp. 174–175 °C; IR (KBr) νmax
−
1
3
1
433, 3260 (2NH), 3047 (CH-arom.), 2927 (CH-aliph.),
620, 1593 (2C=N),1288, 1164 cm
(3NH), 2950 (CH-aliph.), 1596 (C=N) 1338, 1161 cm
,
−
1
1
1
(SO2); H NMR
(SO ); H NMR (DMSO-d , 300 MHz,): δ = 3.8 (s, 3H,
2 6
(
DMSO-d , 300 MHz,): δ = 5.84 (s, 2H, pyrazole-H),
OCH ), 5.9 (s, 2H, pyrazole-H), 6.9–7.9 (m, 13H, Ar-H),
6
3
7
.25–7.87 (m, 14H, Ar-H + 1NH), 8.71, (s, 1H, CH=N),
9.9, 10.1, 10.4 ppm (3s, 3H, 3NH, exchangeable with D O);
2
9
.87,10.64 ppm (2s, 2H, 2NH, exchangeable with D O);
anal. calcd. For C H N O S : C, 57.60; H, 4.41; N,
14.60. Found: C, 57.20; H, 4.10; N, 14.30.
2
23 21
5
3
2
+
EIMS m/z 510 (M ), 75 (100); anal. calcd. For
C H ClN O S : C, 54.06; H, 3.75; N, 16.45. Found: C,
2
3
19
6 2 2
5
4.30; H, 3.40; N, 16.20.
4-(3-(4-hydroxyphenyl)thioureido)-N-(1-phenyl-1H-pyra-
zol-5-yl)benzenesulfonamide (11d) A mixture of 2 (0.01
mol) and 4-aminophenol (0.01mole) in dimethyl-formamide
8 ml containing three drops of triethylamine was refluxed
for 2 h. After cooling, the reaction mixture was poured into
crushed ice water and acidified with dil. HCl. The solid
product obtained by filtration was washed with water and
2
5
-(4-Methoxybenzylidene)-N-(4-(N-(1-phenyl-1H-pyrazol-
-yl)sulfamoyl)phenyl) hydrazinecarbothioamide (10b)
White needles; yield 71%; mp. 158–159 °C; IR (KBr) νmax
3
1
367, 3254 (2NH), 3066 (CH-arom.), 2923 (CH-aliph.),
−1
1
681, 1596 (2C=N) 1384, 1157 cm (SO ); H NMR
,
2
(
DMSO-d , 300 MHz,): δ = 3.87 (s, 3H, OCH ), 5.9 (s, 2H,
recrystallized from DMF/ethanol to give 11d. Yellow
6
3
o
pyrazole-H), 7.06–7.38 (m, 15H, Ar-H + 2NH), 8.6 (s, 1H,
CH=N), 9.9 ppm (s, 1H, NH, exchangeable with D O);
anal. calcd. For C H N O S : C, 56.90; H, 4.38; N,
crystals; yield 88%; mp. 158–160 C; IR (KBr) ν
3375
max
−
1
(OH), 2954 (CH-aliph.), 1596 (C=N), 1330, 1126 cm
2
+
(SO ); EIMS m/z 465 (M ), 73 (100); anal. calcd. For
2
4
22
6
3
2
2
1
6.59. Found: C, 56.60; H, 4.10; N, 16.30.
C H N O S : C, 56.76; H, 4.11; N, 15.04. Found: C,
2
2 19 5 3 2
56.50; H, 4.30; N, 15.30.
General procedure for the synthesis of N-(1-phenyl-1H-
pyrazol-5-yl)-4-(substituded)benzene-sulfonamide (11a–c)
N-(1-phenyl-1H-pyrazol-4-yl)-4-(3-(4-(3-(4-(N-(1-phenyl-
H-pyrazol-5-yl)sulfamoyl)phenyl) thioureido)phenyl)
1
A mixture of 2 (0.01 mol) and the appropriate amine (0.01
mol) in dioxane 10 ml containing three drops of triethyla-
mine was added. The reaction mixture was stirred at room
temperature for 1 h and the solid product that obtained was
collected and recrystallized from dioxane to give 11a–c.
thioureido)benzenesulfonamide (12)
A mixture of 2 (0.02 mol) and p-phenylenediamine (0.012
mol) in dimethylformamide 20 ml containing three drops of
triethylamine was refluxed for 4 h. The solid obtained was

Med Chem Res
o
recrystallized from dioxane to give 12. Yellow crystals;
mp. 130–131 C; IR (KBr) ν
3344, 3217 (2NH), 2927
max
−
1
yield 80%; mp. 90–92 °C; IR (KBr) ν
3367, 3213
(CH-aliph.), 1658 (C=O) 1624 (C=N), 1384, 1157 cm
(SO ); H NMR (DMSO-d , 300 MHz,): δ = 1.23 (t, 3H,
2 6
max
,
−1
1
1
(
(
2NH), 1627 (C=N), 1384, 1153 cm (SO ); H NMR
2
DMSO-d6, 300 MHz,): δ = 5.89 (s,4H, pyrazole-
CH ), 4.47 (q, 2H, CH ), 5.67 (s, 2H, pyrazole-H), 6.47 (s,
3 2
H),6.79–7.87 (m, 22H,Ar-H), 9.37 10.46,10.82 ppm (3s,
1H, pyrazole-H), 7.4–7.64 (m, 15H, Ar- H+ NH), 10.37,
+
6
1
3
H, 6NH, exchangeable with D O); EIMS m/z 820 (M ),
11.71 ppm (2s, 2H, 2NH, exchangeable with D O); EIMS
2
2
66 (100); anal. calcd. For C H N O S : C, 55.59; H,
m/z 558 (M-29 (C H )), 73 (100); anal. calcd. For
3
8
32 10
4
4
2 5
.93; N, 17.06. Found: C, 55.30; H, 3.60; N, 17.40.
C H N O S : C, 57.23; H, 4.29; N, 16.68. Found: C,
28 25 7 4 2
57.40; H, 4.50; N, 16.90.
General procedure for the synthesis of 4-(substituded)-N-
(
(
1-phenyl-1H-pyrazol-5-yl)benzenesulfonamide (14) and
15)
In vitro anticancer screening
EAC cells were maintained in female Swiss albino mice
weighing 25–30 g (the holding company for biological
products and vaccines. VACSERA, Cairo, Egypt) were
housed at a constant temperature (24 laboratory ± 2 °C)
with alternating 12-h light and dark cycles and fed standard
food (Milad Co, Cairo, Egypt) and water ad libitum. All
chemicals and reagents were of the highest grade com-
mercially 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 health
organization, Geneva, Switzerland and approved from the
committee for animal scare at NCRRT, AEA. EAC cells
were obtained by needle aspiration of ascetic fluid from
preinoculated mice; under aseptic conditions. Tumor cells
A mixture of 2 (0.01 mol) and 1,2-phenylenediamine and/or
-aminophenol (0.01mole) in dimethylformamide 20 ml
2
containing three drops of triethylamine was refluxed until
evaluation of hydrogen sulfide had stopped (lead acetate
paper) for 5 h After cooling, the reaction mixture was
poured into crushed ice water, and the solid product
obtained was recrystallized from DMF/ethanol to give 14
and 15, respectively.
4
-(1H-benzo[d]imidazol-2-ylamino)-N-(1-phenyl-1H-pyra-
zol-5-yl)ben-zenesulfonamide (14) White crystals; yield
8
3
1
1%; mp. 100–101 °C; IR (KBr) νmax 3352, 3209 (2NH),
062 (CH-arom.), 2927 (CH-aliph.), 1627, 1593 (2C=N),
−
1
1
377, 1157 cm (SO ); H NMR (DMSO-d , 300 MHz,):
2
6
δ = 5.87 (s, 2H, pyrazole-H), 6.76–7.8 (m, 13H, Ar-H),
.65, 10.20, 10.70 ppm (3s, 3H,3NH, exchangeable with
6
suspension (2.5 × 10 per ml) was prepare dwith various
dilutions by dissolving; 100, 50, 25 and 10 mg of the tested
compounds in DMSO (1 ml). In a set of sterile test tubes,
9
D O); EIMS m/z 431 (M+1), 69 (100); anal. calcd. For
2
C H N O S: C, 61.38; H, 4.21; N, 19.52. Found: C,
2
2 18 6 2
0.8 ml RPMI-1640 media containing (glutamine, fetal calf
6
1.20; H, 4.50; N, 19.20.
serum as nutrient, streptomycin and penicillin), 0.1 ml of
each of the tested compounds (corresponding to 100, 50,
2
5, 10 µg) were mixed then 0.1 ml of tumor cell suspension
4
-(3-(2-hydroxyphenyl)thioureido)-N-(1-phenyl-1H-
6
(2 × 10 ) was added. The test tubes were incubated at 37 °C
pyrazol-5-yl)benzenesulfonamide (15)
for 2 h. Trypan blue exclusion test was carried out to cal-
culate the percentage of non-viable cells after 2 h of incu-
bation (Brusick 1984). The results of in vitro antitumor
screening are presented in Table 1.
Yellow crystals; yield 75%; mp. 109–110 °C; IR (KBr) νmax
3
aliph.),1569 (C=N), 1384,1153 cm (SO ); EIMS m/z 465
352, 3224(OH, NH), 3058 (CH-arom.), 2927 (CH-
−
1
2
+
(
M ), 73 (100); anal. calcd. For C H N O S : C, 56.76;
22 19 5 3 2
No: of non viable
H, 4.11; N, 15.04. Found: C, 56.50; H, 3.90; N, 15.30.
%
of non À viable cells ¼ Total no: of cells  100
Ethyl-1-phenyl-5-(3-(4-(N-(1-phenyl-1H-pyrazol-5-yl)
sulfamoyl)phen-yl)thioureido)-1H -pyrazole-4-carboxylate
Acknowledgements The authors would like to extend their sincere
appreciation to the Deanship of Scientific Research at King Saud
University for its funding of this research through the Research Group
Project No. RGP-VPP- 302
(
17)
A mixture of 2 (0.01 mol), and ethyl-5-amino-1-phenyl-1H-
pyrazole-4-carboxylate in 1,4-dioxane 10 ml containing
three drops of triethylamine was heated under reflux for 3 h.
The reaction mixture was poured into crushed ice water, and
acidified with dil. HCl. The solid obtained was recrys-
tallized from dioxane to give 17. White needles; yield 69%;
Compliance with ethical standards
Conflict of interest The authors declare that they have no competing
interests.

Med Chem Res
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