Synthesis, characterization and antiglaucoma activity of some novel pyrazole derivatives of 5-amino-1,3,4-thiadiazole-2-sulfonamide

Article abstract of DOI:10.1016/j.ejmech.2010.07.041

Pyrazole carboxylic acid derivatives of 5-amino-1,3,4-thiadiazole-2- sulfonamide (inhibitor 1) were synthesized from ethyl 3-(chlorocarbonyl)-1-(3- nitrophenyl)-5-phenyl-1H-pyrazole-4-carboxylate compound. The inhibitory effects of inhibitor 1, acetazolam

Full text of DOI:10.1016/j.ejmech.2010.07.041

European Journal of Medicinal Chemistry 45 (2010) 4769e4773
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European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis, characterization and antiglaucoma activity of some novel pyrazole
derivatives of 5-amino-1,3,4-thiadiazole-2-sulfonamide
*
ꢀ
Rahmi Kasımogulları , Metin Bülbül, B. Seçkin Arslan, Bas¸ ak Gökçe
Department of Chemistry, Faculty of Arts and Sciences, Dumlupinar University, Tavs¸anlı yolu 10 km, 43100 Kutahya, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Pyrazole carboxylic acid derivatives of 5-amino-1,3,4-thiadiazole-2-sulfonamide (inhibitor 1) were
synthesized from ethyl 3-(chlorocarbonyl)-1-(3-nitrophenyl)-5-phenyl-1H-pyrazole-4-carboxylate
compound. The inhibitory effects of inhibitor 1, acetazolamide (AAZ) and of 11 newly synthesized amides
(5aeb, 6, 7aeg, and 8) on hydratase and esterase activities of carbonic anhydrase isoenzymes (hCA-I and
hCA-II) have been studied in vitro. The comparison of newly synthesized amides to inhibitor 1 and to AAZ
indicated that the new derivatives inhibit CA isoenzymes and they are more potent inhibitors than the
parent inhibitor 1 and AAZ.
Received 17 December 2009
Received in revised form
16 July 2010
Accepted 20 July 2010
Available online 24 July 2010
Keywords:
Pyrazole
Ó 2010 Elsevier Masson SAS. All rights reserved.
1,3,4-Thiadiazole-2-sulfonamide
Glaucoma
Inhibition
Carbonic anhydrase
1. Introduction
2. Results and discussion
Sulfonamides are the best-known inhibitors of carbonic anhy-
drase enzyme, currently used for the treatment of glaucoma in
clinical medicine [1e14]. 5-amino-1,3,4-thiadiazole-2-sulfonamide
(1) has several biological activities and antibacterial properties [15].
Several derivatives of this drug have been synthesized and used in
treatment of glaucoma; one of them is acetazolamide (AAZ). AAZ is
used systematically (i.e., an oral medication) and reduces intraoc-
ular pressure by lowering the fluid formation in the eye. A number
of side effects of this drug are however experienced such as
numbness and tingling in the fingers and toes, taste alterations,
blurred vision, kidney stones and an increase in urination. Dorzo-
lamide (DZA) and brinzolamide (BRZ) are two other carbonic
anhydrase inhibitors, formulated for topical ophthalmic use (see
Fig. 1 for the structures) [1,16]. Nevertheless, people taking these
two drugs also experience side effects as stinging, burning, blurred
vision, upset stomach, dry eye, headache or dizziness [1,17e19]. The
purpose of the present study was thus to synthesize and investigate
new inhibitors of carbonic anhydrase isoenzymes with potential
use in the treatment of glaucoma.
In order to synthesize new compounds, activated pyrazole
carboxylic acids were reacted with inhibitor 1, and new amide
derivative (3) was obtained (Scheme 1). The target inhibitor (4) was
prepared by reducing NO2 group to NH2 group using this newly
synthesized amide derivative [20,21].
In our work, the diazotisation method was generally used to
synthesize new derivatives of compound 4 which was an aromatic
amine. As described previously, the diazonium salt of the
compound was prepared [22]. Then the coupling and replacement
reactions were performed. During the reactions, the temperature
was controlled (0e5 ꢀC) and different pH ranges were tested and
the best yield was observed in the range of pH ¼ 3.5e4. The
products were mostly colored and their yields were generally high
(61e89%). The purity of each product was checked by TLC which
was performed for each of the reactions.
The structures of the compounds were characterized by spectral
data (see Experimental). The compound 4 gave the azo compounds
(5a and 5b) by the diazo coupling reaction with aromatic
compounds such as phenol or
b-naphthol. Compound 6 was
produced by interference of the diazonium compound with KI. For
the transfer of ion of Iꢁ, known as a strong nucleophile, KI was
sufficient without any need for a catalyser.
Some of the hydrazo derivatives (7aeg) were produced in high
yields by reaction of compound 4 with aliphatic 1,3-dicarbonile
* Corresponding author. Tel.: þ90 274 265 2031x3204; fax: þ90 274 265 2056.
ꢀ
E-mail address: rahmikasimoglu@hotmail.com (R. Kasımogulları).
0223-5234/$ e see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2010.07.041

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R. Kasımogulları et al. / European Journal of Medicinal Chemistry 45 (2010) 4769e4773
4770
compounds (5aeb, 6, 7aeg, and 8) have generally more inhibitory
N
N
N
N
effect than 1 and AAZ on esterase activity of hCA-I and hCA-II, but
the most effective compounds were 7g for hCA-I, 5a, 7f and 7g for
hCA-II. Ki values of these compounds (5aeb, 6, 7aeg, and 8) were
also lower than the parent compounds (1 and AAZ). Consequently
our synthesized compounds (5aeb, 6, 7aeg, and 8) may be new
candidates for the glaucoma drugs because of their inhibitory
effects.
SO2NH2
SO2NH2
H2N
H3CCOHN
S
S
1
AAZ
NHCH2CH3
NHCH2CH3
SO2NH2
SO2NH2
N
S
S
3. Experimental protocols
S
S
H3C
CH3O(CH2)3
O
O
O
O
3.1. Syntheses
DZA
BRZ
Melting points were measured with Barnstead Electrothermal
9200 apparatus, and did not corrected. IR spectrum data of
compounds were determined with Mattson 1000 FT-IR by using of
KBr pellets. 1H NMR and 13C NMR spectra were evaluated by
BRUKER DPX-400 (400 MHz), and High Performance Digital
FT-NMR (100 MHz) spectrometers. Mass spectra data were deter-
mined by Varian Mat III 80 eV. At the end of the each experiments
TLC was performed using DC Alufolien Kiesegel 60F/254 Merck and
Camag TLC devices. Elemental analyses were carried out on a Leco
CHNS-932 instrument.
Fig. 1. Structures of several CA inhibitors used in glaucoma treatment.
compounds which included active CeH protons [23]. In these
compounds, because of unshared electron couples of nitrogen,
proton which was transferred to base results in the resonance form;
the resulting products may have tautomeric structures as azo
(eN]Ne) or hydrazo (eNHeN]C) [24]. In literature, it has been
reported that such compounds in solid phases and in chloroform
have only keto-hydrazo tautomeric structures because of inter-
molecular hydrogen bonds [25]. As seen from the results of 1H NMR
spectrums, it was obvious that signals of 7aeg compounds at
Compound 4 which is containing aromatic amine function was
prepared as described previously [27].
d
¼ 12.07e11.49 ppm intervals were caused by hydrogen atoms in
covalent linkage with nitrogen. Thus, these compounds including
aliphatic active CeH groups prefer keto-hydrazo (eNHeN]C)
tautomeric structures after coupling.
3.2. General procedure for synthesis of starting compounds (5aeb,
6, and 7aeg)
Finally, the compound 8 was produced by cyclization reaction of
the compound 4 with chloroacetone in DMF at 60 ꢀC for 72 h [26].
Syntheses of compounds 5aeb, 6, 7aeg, and 8 from compound 4
are shown in Scheme 2.
Next, effects of these new inhibitors on human carbonic anhy-
drase I (hCA-I) and II (hCA-II) purified from red blood cells were
investigated. The CA isozymes have been purified to homogeneity
by affinity chromatography.
In the new synthesized compounds, the inhibitor concentra-
tions causing 50% inhibition (IC50 values) were determined from
regression analysis graphs. The inhibition equilibrium constants
(Ki) were also determined in relation to esterase activities. The IC50
and Ki values obtained for erythrocytes hCA-I and hCA-II purified by
affinity chromatography are shown in Table 1. The IC50 and Ki values
were used to compare the inhibitory potential of parent inhibitor 1,
AAZ and the newly synthesized derivatives (5aeb, 6, 7aeg, and 8)
on hCA-I and hCA-II. As seen in Table 1, the IC50 values of the new
compounds (5aeb, 6, 7aeg, and 8) were lower than the IC50 values
of inhibitor 1 and AAZ for hydratase activity of erythrocytes hCA-I
and hCA-II.
To a cooled (0e5 ꢀC) and stirred solution of aromatic amine
(1 mmol) in HCl (2 ml); Sodium acetate (3 g), ethanol (10 ml) and
a cold solution of NaNO2 (83 mg, 1.2 mmol) were added for 15 min.
The reaction mixture was stirred for 45 min in the same tempera-
ture. Aromatic and
b-diketone (1 mmol) compounds were dis-
solved in ethanol and added to solution of diazonium salt by
dropwise which was prepared previously. The obtained precipitate
was isolated by filtration and washed with water. The crude
product was purified from ethanol using recrystallization method.
3.2.1. Ethyl 1-(3-((2-hydroxynaphthalen-1-yl) diazenyl) phenyl)-5-
phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-
pyrazole-4-carboxylate (5a)
(555 mg, 83%); mp 185e186 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 15.5 (s, 1H, Ar-OH), 13.9 (s, 1H, CONH), 8.45 (s, 2H,
SO2NH2), 6.85e7.95 (m, 15H, ArH), 4.13 (q, J ¼ 6.7 Hz, 2H, OCH2CH3),
0.99 (t, J ¼ 6.5 Hz, 3H, CH2CH3); 13C NMR (100 MHz, DMSO-d6)
d
(ppm): 171.64 (ester C]O), 165.41 (amide C]O), 162.03 and
161.33 (thiadiazol C-2 and C-5), 61.12 (OCH2), 14.00
(OCH2CH3), 146.24, 145.58, 145.50, 141.54, 139.86, 132.97, 130.96,
130.82,130.27,130.04,129.77,129.46,128.82,128.75,128.40,128.05,
As we examine IC50 values of synthesized compounds on
esterase activity of hCA-I and hCA-II (Table 1); the synthesized
127.99, 126.83, 124.77, 124.47, 122.10, 120.04, 114.35; IR (n
, cmꢁ1):
O
O
O
O
O
O
R
NH
R
R
NH
OH
Na2Sx9H2O
HCl
SOCl2
N
S
2
S
N
N
N
N
N
Ph
N
Ph
N
Ph
N
SO2NH2
H2N
N
N
SO2NH2
S
N
SO2NH2
Ar
Ar
2
Ar
Ar
R
3
4
Ph-NO2(3)
OEt
Ph-NO2(3)
Ph-NH2(3)
3
4
OEt
OEt
Scheme 1. Synthesis of compounds 3, 4.

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R. Kasımogulları et al. / European Journal of Medicinal Chemistry 45 (2010) 4769e4773
4771
SO2NH2
SO2NH2
SO2NH2
S
S
N
N
N
N
S
N
N
O
O
O
O
N
O
O
O
EtO
N
EtO
NH
EtO
N
H
H
Cl
H3C
DMF, 60 o
N
Ph
N
Ph
N
Ph
N
N
C
CH3
NH2
N
N
N
Ar
4
r
5a, b
A
O
o
C
5
-
0
Ar
5
CH3
HCl
NaNO2
CH3COONa
0 o
8
OH
C
a
b
OH
O
SO2NH2
SO2NH2
SO2NH2
S
N
N
N
N
S
O
O
O
S
N
O
O
EtO
N
O
O
N
H
NH
EtO
EtO
Ph
N
R2
R1
KI
0-5 oC
H
N
0-5 oC
Ph
N
N
N
Ph
N
N
O
N
O
N
R1
N2
Cl
H
I
7a-g
R2
6
R2
R1
7
CH3
CH3
C6H5
C6H5
CH3
OEt
OC(CH3)3
CH3
C6H5
C6H5
OEt
OEt
OEt
CH3
a
b
c
d
e
f
g
Scheme 2. Synthesis of compounds 5aeb, 6, 7aeg, and 8.
3500 (OH), 3201 (NH), 3020 (ArCH), 2987 (aliphatic CH),1724 (ester
C]O), 1666 (amide C]O), 1603e1485 (C]N and C]C), 1434, 1363,
1207, 1172, 1071; Anal. Calcd for C31H24N8O6S2: C, 55.68; H, 3.62; N,
14.36; S, 9.59. Found: C, 55.52; H, 3.69; N, 14.32; S, 9.65.
Ar-OH), 7.05e7.95 (m,13H, ArH), 4.10 (q, J ¼ 6.8 Hz, 2H, OCH2CH3), 0.98
(t, J ¼ 6.5 Hz, 3H, CH2CH3); 13C NMR (100 MHz, DMSO-d6)
d (ppm):
172.57 (ester C]O),167.50 (amide C]O), 163.87 and 162.15 (thiadiazol
C-2 and C-5), 152.88 (ArC-OH), 60.70 (OCH2), 14.24 (OCH2CH3), 145.41,
144.80, 143.50, 143.30, 140.35, 140.19, 130.33, 130.15, 129.47,
3.2.2. Ethyl 1-(3-((4-hydroxyphenyl)diazenyl)phenyl)-5-phenyl-3-
(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-pyrazole-4-
carboxylate (5b)
129.10,128.85,127.90,126.03,125.60,116.55,100.01; IR (n
, cmꢁ1): 3407
(OH), 3279 (NH), 3020 (ArCH), 2970 (aliphatic CH), 1738 (ester C]O),
1665 (amide C]O), 1630e1485 (C]N and C]C), 1548, 1411, 1367,
1216, 1170, 1071. Anal. Calcd for C27H22N8O6S2: C, 52.42; H, 3.58;
N, 18.11; S, 10.37. Found: C, 52.35; H, 3.65; N, 18.10; S, 10.45.
(544 mg, 88%); mp 201e202 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 12.6 (br, s, 1H, CONH), 8.20 (br, s, 2H, SO2NH2), 6.35 (s, 1H,
3.2.3. Ethyl 1-(3-iodophenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-
thiadiazol-2-ylcarbamoyl)-1H-pyrazole-4-carboxylate (6)
Table 1
IC50 and Ki values of hCA-I and hCA-II isoenzyme hydratase and esterase activities
The solution of diazonium salt of the compound 4 was prepared
according to the general procedure. The cold solution of KI (656 mg,
1 mmol) inwater (10 ml) was added dropwise to solution of diazonium
salt which was prepared before. The precipitated yellow product was
filtered, washed with water and recrystallized from ethanol. (375 mg,
obtained after inhibition experiments.
Inhibitor
Hydratase IC50
M)
Esterase IC50
M)
Ki values (mM)
(
m
(m
hCA-I
hCA-II
hCA-I
hCA-II
hCA-I
hCA-II
1
3.30
3.80
0.55
0.12
0.05
0.08
0.02
0.41
0.09
0.14
0.13
0.14
0.07
2.90
4.10
0.48
0.47
0.05
0.45
0.58
0.26
0.59
0.11
0.14
0.16
0.08
2.70
3.10
1.05
1.25
0.11
0.32
0.46
0.78
6.10
0.20
0.30
0.10
0.30
3.20
8.20
0.08
0.45
0.13
0.21
0.34
0.35
2.30
0.16
0.06
0.04
0.24
5.90
6.30
1.48
1.63
0.09
0.25
0.46
0.74
5.92
0.20
0.27
0.11
0.38
7.40
3.30
0.38
0.95
0.07
0.17
0.19
0.41
2.17
0.12
0.05
0.03
0.23
60%); mp 173e174 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d (ppm): 13.65
AAZ
5a
5b
6
7a
7b
7c
7d
7e
7f
(br, s,1H, CONH), 8.44 (s, 2H, SO2NH2), 7.48e7.34 (m, 9H, ArH), 4.09 (q,
J ¼ 7.0 Hz, 2H, OCH2CH3), 0.98 (t, J ¼ 7.1 Hz, 3H, CH2CH3); 13C NMR
(100 MHz, DMSO-d6) d (ppm): 165.45 (ester C]O),162.02 (amide C]
O), 161.90 and 161.35 (thiadiazol C-2 and C-5), 94.96 (ArC-I), 61.03
(OCH2),13.98 (OCH2CH3),146.28,145.34,138.62,130.79,130.08,129.62,
129.49, 128.77, 128.67, 128.03, 126.26, 113.92, IR (n
, cmꢁ1): 3211 (NH),
3025 (ArCH), 2970 (aliphatic CH), 1738 (ester C]O), 1663 (amide C]
O), 1540e1463 (C]N and C]C),1432,1364,1171,1065; Anal. Calcd for
C21H17N6O5S2: C, 40.39; H, 2.74; N, 13.46; S, 10.27. Found: C, 40.31; H,
2.77; N, 13.45; S, 10.21.
7g
8

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4772
3.2.4. Ethyl 1-(3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)
phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-
1H-pyrazole-4-carboxylate (7a)
128.72, 128.65, 127.98, 120.53, 113.98, 94.55; IR (n
, cmꢁ1); 3233
(NH), 3059, 2991 (ArCH), 2935 (aliphatic CH), 1738, 1665 (C]O),
1606e1534 (C]N and C]C), 1439, 1363, 1211, 1171; Anal. Calcd for
C32H28N8O8S2: C, 53.62; H, 3.94; N, 15.63; S, 8.95. Found: C, 53.58;
H, 3.96; N, 15.67; S, 9.01.
(362 mg, 58%); mp 174e175 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 13.53 (br, s, 1H, CONH), 11.51 (s, 1H, Ar-NHeN]C), 8.10
(s, 2H, SO2NH2), 7.51e7.15 (m, 9H, ArH), 4.25 (q, J ¼ 6.9 Hz, 2H,
OCH2CH3), 2.60 and 2.42 (s, 6H, COCH3), 1.09 (t, J ¼ 7.0 Hz, 3H,
3.2.8. Ethyl 1-(3-(2-(1-ethoxy-1,3-dioxobutan-2-ylidene)
hydrazinyl)phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-
ylcarbamoyl)-1H-pyrazole-4-carboxylate (7e)
CH2CH3); 13C NMR (100 MHz, DMSO-d6)
d (ppm): 202.42 and 201.42
(acetyl C]O), 170.30 (ester C]O), 168.29 (amide C]O), 163.99 and
151.90 (thiadiazol C-2 and C-5), 66.46 (OCH2), 36.37 and 31.50
(COCH3), 18.32 (CH2CH3), 149.19, 147.12, 144.31, 138.42, 135.01,
134.96, 134.50, 133.21, 132.77, 126.83, 121.70, 121.50, 118.76, 117.50;
(419 mg, 64%); mp 186e187 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 13.91 (br, s, 1H, CONH), 11.49 (s, 1H, Ar-NHeN]C), 8.41
(s, 2H, SO2NH2), 7.48e6.97 (m, 9H, ArH), 4.29 and 4.09 (q, J ¼ 7.1 Hz,
IR (n
, cmꢁ1): 3199 (NH), 3020 and 2970 (ArCH), 2924 (aliphatic CH),
4H, 2OCH2CH3), 2.31 (s, 3H, COCH3), 1.27 and 0.98 (t, J1 ¼7.0 Hz,
1739 and 1662 (C]O), 1606e1495 (C]N and C]C), 1548, 1430,
1364, 1217, 1171; Anal. Calcd for C26H24N8O7S2: C, 49.99; H, 3.87;
N, 17.94; S, 10.27. Found: C, 49.85; H, 3.89; N, 17.89; S, 10.32.
J2 ¼ 4.9 Hz, 6H, 2CH2CH3); 13C NMR (100 MHz, DMSO-d6)
d (ppm):
194.22 (acetyl C]O), 165.32 and 164.35 (ester C]O), 162.80 (amide
C]O), 162.02 and 161.56 (thiadiazol C-2 and C-5), 61.77 and 61.03
(OCH2), 25.80 (COCH3), 14.32 and 13.98 (CH2CH3), 146.12, 143.69,
139.59, 133.04, 130.70, 130.60, 130.13, 128.76, 128.58, 128.01,
3.2.5. Ethyl 1-(3-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)
hydrazinyl)phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-
ylcarbamoyl)-1H-pyrazole-4-carboxylate (7b)
120.68, 115.87, 113.99, 112.50; IR (n
, cmꢁ1): 3223 (NH), 3068, 2978
(ArCH), 2935 (aliphatic CH), 1731, 1675 (C]O), 1606e1522 (C]N
and C]C), 1432, 1361, 1207, 1165; Anal. Calcd for C27H26N8O8S2: C,
49.53; H, 4.00; N, 17.12; S, 9.80. Found: C, 49.45; H, 4.03; N, 17.13; S,
9.87.
(480 mg, 70%); mp 136e137 ꢀC; 1H NMR (400 MHz, CDCl3)
d
(ppm): 13.43 (br, s, 1H, CONH), 12.07 (s, 1H, Ar-NHeN]C), 7.87 (s,
2H, SO2NH2), 7.56e6.77 (m, 14H, ArH), 4.16 (q, J ¼ 6.7 Hz, 2H,
OCH2CH3), 2.21 (s, 3H, COCH3), 0.91 (t, J ¼ 6.3 Hz, 3H, CH2CH3); 13
C
NMR (100 MHz, CDCl3)
d
(ppm): 198.55 (acetyl C]O), 191.85
3.2.9. Diethyl 2-(2-(3-(4-(ethoxycarbonyl)-5-phenyl-3-(5-
sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-pyrazol-1-yl)
phenyl)hydrazono)malonate (7f)
(benzoyl C]O), 164.99 (ester C]O), 164.89 (amide C]O), 161.45
and 158.21 (thiadiazol C-2 and C-5), 62.50 (OCH2), 30.44 (COCH3),
13.25 (CH2CH3), 143.50, 142.43, 139.17, 137.80, 133.31, 132.49,
132.33, 130.43, 130.15, 130.04, 128.64, 128.55, 128.26, 128.06, 127.01,
(520 mg, 76%); mp 149e150 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 13.81 (br, s, 1H, CONH), 11.84 (s, 1H, Ar-NHeN]C), 8.38 (s,
121.91, 113.41, 96.75; IR (
n
, cmꢁ1); 3240 (NH), 3025, 2970 (ArCH),
2H, SO2NH2), 7.51e7.33 (m, 9H, ArH), 4.41, 4.18 and 4.11 (q, 6H,
2935 (aliphatic CH), 1738 and 1662 (C]O), 1596e1495 (C]N and
C]C), 1434, 1363, 1216, 1171; Anal. Calcd for C31H26N8O7S2: C,
54.22; H, 3.82; N, 16.32; S, 9.34. Found: C, 54.15; H, 3.88; N, 16.32; S,
9.41.
3OCH2CH3), 1.26 (m, 6H, 2CH2CH3), 0.99 (t, 3H, CH2CH3); 13C NMR
(100 MHz, DMSO-d6) d (ppm): 165.49, 162.64 and 162.06 (ester C]
O), 161.97 (amide C]O), 161.86 and 161.39 (thiadiazol C-2 and C-
5), 61.87, 61.39 and 61.02 (OCH2), 14.53, 14.30 and 13.96 (CH2CH3),
146.30, 143.70, 138.66, 130.77, 130.70, 130.05, 129.59, 129,46,
3.2.6. Ethyl 1-(3-(2-(1,3-dioxo-1,3-diphenylpropan-2-ylidene)
hydrazinyl)phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-
ylcarbamoyl)-1H-pyrazole-4-carboxylate (7c)
128.68, 128.65, 128.08, 126.25, 113.96, 112.75; IR (n
, cmꢁ1); 3128
(NH), 3064, 2978 (ArCH), 2936 (aliphatic CH), 1728 (ester C]O),
1667 (amide C]O), 1604e1491 (C]N and C]C), 1435, 1363, 1210,
1168; Anal. Calcd for C28H28N8O9S2: C, 49.12; H, 4.12; N, 16.37; S,
9.37. Found: C, 49.03; H, 4.16; N, 16.35; S, 9.42.
(516 mg, 69%); mp 161e162 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 13.90 (br, s, 1H, CONH), 11.66 (s, 1H, Ar-NHeN]C), 8.44
(s, 2H, SO2NH2), 8.18e6.80 (m, 19H, ArH), 4.08 (q, J ¼ 7.0 Hz, 2H,
OCH2CH3), 0.98 (t, J ¼ 7.1 Hz, 3H, CH2CH3); 13C NMR (100 MHz,
3.2.10. Ethyl 1-(3-(2-(1-tert-butoxy-1,3-dioxobutan-2-ylidene)
hydrazinyl)phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-
ylcarbamoyl)-1H-pyrazole-4-carboxylate (7g)
DMSO-d6) d (ppm): 194.19 and 190.80 (benzoyl C]O), 165.52 (ester
C]O), 163.85 (amide C]O), 161.86 and 161.35 (thiadiazol C-2 and
C-5), 60.99 (OCH2), 13.96 (CH2CH3), 146.13, 145.75, 144.32, 139.49,
138.41, 137.25, 136.30, 135.05, 134.65, 133.50, 132.87, 130.73, 130.59,
129.54, 129.32, 129.10, 128.98, 128.65, 128.48, 127.89, 113.78, 93.73;
(475 mg, 70%); mp 166e167 ꢀC; 1H NMR (400 MHz, DMSO-d6)
d
(ppm): 13.81 (br, s, 1H, CONH), 11.49 (s, 1H, Ar-NHeN]C), 8.37 (s,
2H, SO2NH2), 7.50e7.01 (m, 9H, ArH), 4.11 (q, 2H, OCH2CH3), 2.30 (s,
IR (n
, cmꢁ1); 3195 (NH), 3027 and 2970 (ArCH), 2924 (aliphatic CH),
3H COCH3), 1.52 (s, 9H, OC(CH3)3), 0.99 (t, 3H, CH2CH3); 13C NMR
1739 (ester C]O), 1688 and 1668 (benzoyl C]O), 1654 (amide C]
O), 1595e1484 (C]N and C]C), 1540, 1448, 1362, 1213, 1168; Anal.
Calcd for C36H28N8O7S2: C, 57.74; H, 3.77; N, 14.96; S, 8.56. Found: C,
57.62; H, 3.80; N, 14.95; S, 8.61.
(100 MHz, DMSO-d6) d (ppm): 194.21 (acetyl C]O), 165.44, 162.03
(ester C]O), 161.87 (amide C]O), 161.48 and 161.41 (thiadiazol C-2
and C-5), 83.58 (OC(CH3)3), 61.04 (OCH2), 28.39 (OC(CH3)3), 26.40
(COCH3), 13.97 (CH2CH3), 146.21, 143.65, 139.58, 132.54, 130.70,
130.49, 130.11, 128.73, 128.05, 120.86,116.20, 114.01, 112.84; IR
3.2.7. Ethyl 1-(3-(2-(1-ethoxy-1,3-dioxo-3-phenylpropan-2-
ylidene)hydrazinyl)phenyl)-5-phenyl-3-(5-sulfamoyl-1,3,4-
thiadiazol-2-ylcarbamoyl)-1H-pyrazole-4-carboxylate (7d)
(609 mg, 85%); mp 232e233 ꢀC; 1H NMR (400 MHz, DMSO-d6)
(n
, cmꢁ1); 3219 (NH), 3069, 2976 (ArCH), 2933 (aliphatic CH), 1733,
1676 (C]O), 1606e1523 (C]N and C]C), 1434, 1363, 1214, 1147;
Anal. Calcd for C29H30N8O8S2: C, 51.02; H, 4.43; N, 16.41; S, 9.39.
Found: C, 50.90; H, 4.45; N, 16.43; S, 9.45.
d
(ppm): 13.88 (br, s, 1H, CONH), 11.93 (s, 1H, Ar-NHeN]C), 8.36
(s, 2H, SO2NH2), 8.11e6.85 (m, 14H, ArH), 4.33 and 4.09 (q,
J1 ¼7.1 Hz, J2 ¼ 7.0 Hz, 4H, 2OCH2CH3), 1.26 and 0.99 (t, J1 ¼7.1 Hz,
3.2.11. Ethyl 1-(2-methyl-1-(2-oxopropyl)-1H-indol-4-yl)-5-
phenyl-3-(5-sulfamoyl-1,3,4-thiadiazol-2-ylcarbamoyl)-1H-
pyrazole-4-carboxylate (8)
The aromatic amine compound 4 (1 mmol, 513 mg) was dis-
solved in 15 ml DMF and chloroacetone (0.182 ml) was added to the
mixture. The reaction was refluxed at 60 ꢀC for 72 h. After evapo-
ration of solvent of dark colored mixture in rotary evaporator,
J2 ¼ 4.6 Hz, 6H, 2CH2CH3); 13C NMR (100 MHz, DMSO-d6)
d (ppm):
189.23 (benzoyl C]O), 169.81 and 164.93 (ester C]O), 163.22
(amide C]O),162.71 and 162.09 (thiadiazol C-2 and C-5), 61.82 and
60.96 (OCH2), 14.32 and 13.99 (CH2CH3), 145.86, 143.78, 139.59,
137.30, 136.15, 133.10, 130.66, 130.55, 130.37, 129.99, 129.55, 129.02,

ꢀ
R. Kasımogulları et al. / European Journal of Medicinal Chemistry 45 (2010) 4769e4773
4773
remainder dense liquid was added to water and mixed. The gran-
ulated product was filtered and recrystallized from ethanol.
(371 mg, 61%); mp 143e145 ꢀC; 1H NMR (400 MHz, DMSO-d6)
measured in the presence of various substrate concentrations
(0.3 mM, 0.4 mM, 0.5 mM, 0.6 mM and 0.7 mM) and the data was
linearized with Lineweaver-Burke plot for Vmax’ (apparent Vmax)
and the Ki determination [32].
d
(ppm): 13.89 (br, s, 1H, CONH), 8.44 (s, 2H, SO2NH2), 7.37e7.86
(m, 8H, ArH), 6.69 (eCH]), 4.40 (NeCH2eCO), 4.09 (OCH2), 2.51,
2.28 and 0.98 (s, 9H, CH3); 13C NMR (100 MHz, DMSO-d6) (ppm):
d
Acknowledgements
202.21 (acetyl C]O), 165.47 (ester C]O), 161.96 (amide C]O),
161.37 and 160.45 (thiadiazol C-2 and C-5), 61.02 (OCH2), 58.68
(NeCH2eCO), 29.11, 13.97 and 13.90 (CH3), 146.33, 145.65, 139.35,
138.93, 136.27, 130.71, 129.95, 128.70, 127.93, 121.29, 119.77,
This study was funded by The Scientific and Research Council of
Turkey (TÜBITAK) with Grant No 106T180.
117.49, 116.90, 115.03, 113,74; IR (n
, cmꢁ1): 3198 (NH), 3059, 3028
References
(Ar CH), 2970, 2924 (aliphatic CH), 1722 (ester C]O), 1665 (amide
C]O), 1604e1483 (C]N and C]C), 1433, 1409, 1352, 1322, 1213,
1169, 1068; MS (CI) m/z 609 (M þ 1); Anal. Calcd for C27H25N7O6S2:
C, 53.37; H, 4.15; N,16.14; S,10.55. Found: C, 53.25; H, 4.18; N,16.20;
S, 10.49.
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