Synthesis and biological evaluation of 3-(1H-indol-3-yl)pyrazole-5- carboxylic acid derivatives

Article abstract of DOI:10.1007/s12272-011-0301-2

A series of novel compounds bearing a 3-(1H-indol-3-yl)pyrazole-5- carboxylic acid nucleus were synthesized. Analytical and spectral data confirmed the structures of the new compounds. The structures of the regioisomers in this series were determined by 1

Full text of DOI:10.1007/s12272-011-0301-2

Arch Pharm Res Vol 34, No 3, 343-355, 2011
DOI 10.1007/s12272-011-0301-2
Synthesis and Biological Evaluation of 3-(1H-indol-3-yl)pyrazole-
5-carboxylic Acid Derivatives
Datong Zhang1, Guangtian Wang1, Chubing Tan2, Weiren Xu2, Yuan Pei2, and Lingyan Huo1
2
1School of Chemical Engineering, Shandong Polytechnic University, Jinan, Shandong 250353, China and Tianjin Key
Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin 300193, China
(Received June 12, 2010/Revised August 17, 2010/Accepted August 22)
A series of novel compounds bearing a 3-(1H-indol-3-yl)pyrazole-5-carboxylic acid nucleus
were synthesized. Analytical and spectral data confirmed the structures of the new com-
pounds. The structures of the regioisomers in this series were determined by 1H-NMR spectra.
The title compounds were evaluated for their endothelin-1 antagonist activities. In the in vitro
functional assay, compounds 23
,
24
,
28 and 29 exhibited significant efficacy at the concentra-
5c, 26 and 28 were as potent as the positive control
tion of 1 g/mL, and compounds 5b
µ
,
bosentan at high concentration. In the experiment to assess prevention of endothelin-1-
induced sudden death in mice, compound 5b showed comparable activity to bosentan, and 30
was more potent than bosentan. The final compounds were also screened for antibacterial
activity against four Gram-positive and -negative bacteria. Some of the tested compounds
showed weak antibacterial activity.
Key words: Indole, Pyrazole, Endothelin-1 antagonist activity, Antibacterial activity, Struc-
ture-activity relationships (SAR)
with various biological properties, viz. endothelin
Selected by Editors
antagonistic (Zhang et al., 2000), antinociceptive
(Karthikeyan et al., 2009), antibacterial (Akbas et al.,
2005), antiviral (El-Sabbagh et al., 2009), antitumor
(Shawali et al., 2010), antidepressant and anticon-
INTRODUCTION
Both indole and pyrazole derivatives have a wide vulsant (Abdel-Aziz et al., 2009) activities. Encouraged
variety of bioactivities and have attracted considerable by the above observations and the interesting pharm-
interest in the discovery and development of new aceutical activities of N-containing heterocycles, we
classes of drugs over the years. A number of indole investigated a series of compounds bearing the 3-(1H-
derivatives possess interesting activities such as anti- indol-3-yl)pyrazole-5-carboxylic acid nucleus. There
inflammatory (Singh et al., 2008), endothelin antagonist were only few examples reported in the literature for
(Rawson et al., 2002), antifungal (Basavarajaiah the scaffold (Fig. 1) (Gorbunova and Suvorov, 1973).
and Mruthyunjayaswamy, 2009) and antibacterial Various substituents were introduced into the nitrogen
(Yamamoto and Kurazono, 2007) activities. Pyrazole, atoms of indole and pyrazole. In this paper, the
the potent basic pharmacophore, has been associated
Correspondence to: Datong Zhang, School of Chemical Engi-
neering, Shandong Polytechnic University, Shandong Province
250353, China
Tel: 86-531-89631208, Fax: 86-531-89631207
E-mail: dt_zhang@yahoo.com.cn; dtzhang@spu.edu.cn
Chubing Tan, Tianjin Key Laboratory of Molecular Design and
Drug Discovery, Tianjin Institute of Pharmaceutical Research,
Tianjin 300193, China
Tel: 86-22-23003529, Fax: 86-22-23006862
E-mail: tancb@tjipr.com
Fig. 1. General structure of target compounds.
343

344
D. Zhang et al.
synthesis of the title compounds was described and merged in 7.06~7.20 ppm), 7.06~7.20 (m, 2.3H, ArH),
their endothelin-1 antagonistic and antibacterial 7.39/7.46 (d/d (30:70), = 8.0 Hz, 1H, ArH), 7.82~7.84
(m, 1.7H, ArH), 8.13 (d, = 8.0 Hz, 0.3H, ArH; the
proton signal of the major isomer was merged in
7.82~7.84 ppm); IR (KBr,
/cm-1) 3250, 2900, 1675,
1565, 1410, 1210, 1090, 720.
J
activities were evaluated.
J
ν
MATERIALS AND METHODS
All reagents were used as purchased from commercial
suppliers without further purification unless otherwise
noted. Melting points were determined using a WRS-1B
General procedure for compounds 4
As an example, benzyl chloride (1.08 g, 8.58 mmol),
Digital Melting-Point apparatus and were uncorrected. KBr (1.02 g, 8.58 mmol), tetrabutyl ammonium
Thin-layer chromatography (TLC) was performed on bromide (200 mg) and compound (1 g, 3.9 mmol)
3
Silica Gel F254 plates with visualization by UV or were mixed in 5 mL of DMF and then NaH (206 mg,
1
iodine vapor. H-NMR spectra of DMSO-d6 solutions 8.58 mmol, 60%) was added in portions. After stirring
(TMS as an internal standard) were recorded on at r.t. for 4 h, the mixture was quenched with water
Bruker AVANCE II 400 and Varian INOVA-600 and extracted with CH2Cl2 (3 × 20 mL). The combined
spectrometers. The IR spectra were measured on a organic layers were washed with water and brine,
Bruker Vector FT-IR spectrophotometer as KBr pellets dried (Na2SO4), and concentrated. The residue was
or film. Mass spectra were obtained with an API 4000 purified by flash column chromatography (silica gel,
spectrometer. The high-resolution mass spectra were PE/EtOAc, 10:1) to give a light yellow oil that was
obtained with an Agilent-6510-Q-TOF spectrometer.
recrystallized from PE/EtOAc to afford compound 4a
(0.91 g, 53.8%). Compounds 4b and 4c were prepared
analogously to compound 4a but without KBr and
Procedure for the synthesis of compound 3
Ethyl 4-(1-methyl-1
noate (2)
H-indol-3-yl)-2,4-dioxobuta- tetrabutyl ammonium bromide.
Sodium ethoxide (5.8 g, 85.3 mmol) was added to a Ethyl 1-benzyl-3-(1-benzyl-1H-indol-3-yl)-1H-pyra-
mixture of 3-acetylindole (6.23 g, 39 mmol) and zole-5-carboxylate (4a)
diethyl oxalate (6.9 mL). After being stirred for 2 h at White powder, yield 54%; m.p. 117.7-118.4oC; 1H-NMR
75oC, the reaction was quenched by aqueous acetic (400 MHz, DMSO-d6
acid and then stirred for another 30 min. After filtration, OCH2CH3), 4.30 (q,
the precipitate was washed twice with aqueous acetic (s, 2H, CH2Ph), 5.77 (s, 2H, CH2Ph), 7.09~7.17 (m, 2H,
acid and water successively, and then dried to afford a ArH), 7.21~7.34 (m, 11H, ArH, 4-H), 7.50 (d, = 8.0
yellow solid (11.6 g, 99%), m.p. 180.8-182.7oC.
Hz, 1H, ArH), 8.08 (s, 1H, IndH), 8.15 (d, = 8.0 Hz,
1H, ArH); ESI-MS m/z: 436.2 [M+H]+, 458.2 [M+Na]+;
-pyrazole-3-carboxylate IR (KBr,
/cm-1) 3061, 3029, 2925, 2907, 1715, 1581,
1471, 1453, 1262, 1090, 747, 725.
)
J
δ
: 1.28 (t,
= 7.2 Hz, 2H, OCH2CH3), 5.43
J = 7.2 Hz, 3H,
J
J
Ethyl 5-(1
(3)
H
-indol-3-yl)-1
H
ν
Hydrazine hydrate (5.8 g, 116 mmol, 80%) was
added to a mixture of isopropyl alcohol (33 mL) and Ethyl 1-butyl-3-(1-butyl-1
glacial acetic acid (14 mL) cooled in ice water, and zole-5-carboxylate (4b)
then compound
(3.4 g, 13.2 mmol) was added in Light yellow oil, yield 72%; 1H-NMR (400 MHz,
portions. After being stirred for 2 h, the mixture was DMSO-d6 : 0.86~0.92 (m, 6H, CH2CH2CH2CH3),
poured into 100 mL of water and extracted with 1.22~1.34 (m, 7H, CH2CH2CH2CH3, OCH2CH3), 1.72~
CH2Cl2 (3 50 mL). The combined organic layers were 1.83 (m, 4H, CH2CH2CH2CH3), 4.18 (t, = 6.8 Hz, 2H,
then washed with brine, dried (Na2SO4), and con- CH2CH2CH2CH3), 4.32 (q, = 7.2 Hz, 2H, OCH2CH3),
centrated to afford the desired intermediate (3.2 g, 95% 4.53 (t, = 7.0 Hz, 2H, CH2CH2CH2CH3), 7.11 (t,
yield) as a pale yellow solid that was carried forward 7.0 Hz, 1H, ArH), 7.15~7.19 (m, 2H, ArH, 4-H), 7.49
without further purification, m.p. 186.4-186.6oC.
(d, = 8.0 Hz, 1H, ArH), 7.89 (s, 1H, IndH), 8.12 (d,
= 8.0 Hz, 1H, ArH); IR (KBr,
/cm-1) 3049, 2962, 2935,
H-indol-3-yl)-1H-pyra-
2
)
δ
×
J
J
J
J =
J
J
ν
Ethyl 3-(1
H
-indol-3-yl)-1
H
-pyrazole-5-carboxylate 2537, 1699, 1513, 1472, 1248, 1175, 1083, 1069, 809,
(major/minor = 70:30) (3)
Yellow solid, yield 95%; m.p. 186.4-186.6ºC; H-NMR
766, 739.
1
(400 MHz, DMSO-d6
4.26~4.34 (m, 2H, OCH2CH3), 6.98 (d,
0.7H, ArH; the proton signal of the minor isomer was Colorless oil, yield 41%; H-NMR (600 MHz, DMSO-
)
δ
: 1.29~1.30 (m, 3H, OCH2CH3), Ethyl 1-propyl-3-(1-propyl-1
H-indol-3-yl)-1H-
J
= 2.0 Hz, pyrazole -5-carboxylate (4c)
1

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
345
d6
)
δ
: 0.75~0.78 (m, 6H, CH2CH2CH3), 1.34 (t,
J
= 7.2 CH2CH2CH3), 1.78~1.87 (m, 4H, CH2CH2CH3), 4.16
Hz, 3H, OCH2CH3), 1.82~1.87 (m, 4H, CH2CH2CH3), (t,
4.16 (t, = 6.9 Hz, 2H, CH2CH2CH3), 4.33 (q, = 7.2 Hz, 2H, CH2CH2CH3), 7.10~7.12 (m, 2H, ArH, 4-H), 7.18
2H, OCH2CH3), 4.50 (t, = 7.2 Hz, 2H, CH2CH2CH3), (t, = 7.8 Hz, 1H, ArH), 7.51 (d, = 8.4 Hz, 1H, ArH),
7.12 (t, = 7.5 Hz, 1H, ArH), 7.17~7.20 (m, 2H, ArH, 7.85 (s, 1H, IndH), 8.13 (d, = 7.8 Hz, 1H, ArH); IR
4-H), 7.51 (d, = 7.8 Hz, 1H, ArH), 7.91 (s, 1H, IndH), (KBr,
/cm-1) 3421, 3050, 2963, 2927, 2855, 1705,
8.14 (d, = 7.8 Hz, 1H, ArH); IR (KBr,
/cm-1) 3100, 1581, 1521, 1496, 1224, 1145, 1071, 761, 724; ESI-MS
J = 6.9 Hz, 2H, CH2CH2CH3), 4.51 (t, J = 6.9 Hz,
J
J
J
J
J
J
J
J
ν
J
ν
3050, 2960, 2945, 2875, 1710, 1580, 1525, 1455, 1270, m/z: 312.0 [M+H]+, 334.0 [M+Na]+; HRMS (ESI) calcd
1100, 870, 745.
for [M+H]+ C18H22N3O2: 312.1712, found: 312.1702.
General procedure for compounds 5
To a solution of compound 4a (0.83 g, 1.9 mmol) in
General procedure for compounds 6-11
To a stirred mixture of 3 (10 mmol), KOH (13 mmol)
ethanol (8 mL), 20% aqueous sodium hydroxide (4 and KBr (10 mmol) in dried DMSO (8 mL) under
mL) was added, and the resulting mixture was nitrogen was added benzyl chloride (11 mmol), and
refluxed for 1 h (or until the mixture became clear). the resulting mixture was stirred at r.t. for 6 h. The
The reaction mixture was diluted with water, acidified mixture was then poured into water and extracted
to pH 3 with dilute hydrochloric acid, extracted with with CH2Cl2 (3
× 30 mL). The combined organic layers
CH2Cl2 (3 20 mL), dried (Na2SO4), and concentrated were washed with water and brine, dried (Na2SO4),
×
to afford compound 5a, a light yellow solid (0.72 g, and concentrated. The brown oil was purified by flash
93%). Compounds 5b and 5c were prepared as column chromatography (silica gel, PE/EtOAc) to give
described for compound 5a
.
the desired product. For compounds 6 and 8, their
regioisomers (compounds and ) were also obtained.
7
9
1-Benzyl-3-(1-benzyl-1H-indol-3-yl)-1H-pyrazole-
5-carboxylic acid (5a)
Light yellow solid, yield 93%; m.p. 208.3-209.4ºC; H- carboxylate (6)
Ethyl 1-benzyl-3-(1
H
-indol-3-yl)-1
H
-pyrazole-5-
1
1
NMR (400 MHz, DMSO-d6
5.78 (s, 2H, CH2Ph), 7.13~7.17 (m, 2H, ArH), NMR (400 MHz, DMSO-d6
7.20~7.34 (m, 11H, ArH, 4-H), 7.48 (d, = 8.0 Hz, 1H, OCH2CH3), 4.29 (q, = 7.0 Hz, 2H, OCH2CH3), 5.77
ArH), 8.02 (s, 1H, IndH), 8.14 (t, = 8.0 Hz ,1H, ArH); (s, 2H, CH2Ph), 7.06~7.14 (m, 2H, ArH), 7.21~7.27 (m,
IR (KBr, = 8.0
/cm-1) 3413, 3059, 3032, 1689, 1585, 1522, 4H, ArH,4-H), 7.31~7.35 (m, 2H, ArH), 7.41 (d,
= 2.8 Hz, 1H, IndH), 8.14 (d,
= 7.7 Hz, 1H, ArH); 345.8 [M+H]+, 367.8 [M+Na]+;
IR (KBr,
/cm-1) 3333, 3032, 2979, 2945, 1689, 1586,
1456, 1272, 1097, 741, 720.
)
δ
: 5.43 (s, 2H, CH2Ph), Light yellow solid, yield 72%; m.p. 187-189oC; H-
) δ: 1.29 (t, J = 7.0 Hz, 3H,
J
J
J
ν
J
1466, 1288, 1093, 763, 736; ESI-MS m/z: 408.2 Hz, 1H, ArH), 7.88 (d,
J
[M+H]+, 430.2 [M+Na]+; HRMS (ESI) calcd for [M+H]+
C26H23N3O2: 408.1712, found: 408.1719.
J
ν
1-Butyl-3-(1-butyl-1
carboxylic acid (5b)
Light yellow solid, yield 96%; m.p. 134.3-134.7oC; carboxylate (7)
1H-NMR (400 MHz, DMSO-d6 : 0.86~0.92 (m, 6H, Light yellow solid, yield 16%; m.p. 121.7-121.9oC; 1H-
CH2CH2CH2CH3), 1.21~1.32 (m, 4H, CH2CH2CH2CH3), NMR (400 MHz, DMSO-d6 : 1.30 (t, = 7.2 Hz, 3H,
1.72~1.81 (m, 4H, CH2CH2CH2CH3), 4.17 (t, = 6.8 OCH2CH3), 4.29 (q, = 7.2 Hz, 2H, OCH2CH3), 5.51
Hz, 2H, CH2CH2CH2CH3), 4.54 (t, = 6.8 Hz, 2H, (s, 2H, CH2Ph), 6.93 (s, 1H, 4-H), 6.98 (d, = 6.8 Hz,
CH2CH2CH2CH3), 7.08~7.12 (m, 2H, ArH, 4-H), 2H, ArH), 7.08~7.12 (m, 1H, ArH), 7.16~7.29 (m, 4H,
7.15~7.18 (m, 1H, ArH), 7.48 (d, = 8.0 Hz, 1H, ArH), ArH), 7.44~7.46 (m, 2H, ArH), 7.53 (d, = 7.6 Hz,
7.83 (s, 1H, IndH), 8.11 (d,
= 8.0 Hz, 1H, ArH); IR IndH); ESI-MS m/z: 345.9 [M+H]+, 367.8 [M+Na]+; IR
(KBr,
/cm-1) 3124, 3050, 2958, 2927, 2868, 1714, (KBr, /cm-1) 3286, 3058, 2976, 2930, 1723, 1587,
1443, 1245, 1216, 1034, 724.
H-indol-3-yl)-1H-pyrazole-5-
Ethyl 2-benzyl-3-(1H-indol-3-yl)-1H-pyrazole-5-
)
δ
)
δ
J
J
J
J
J
J
J
J
ν
ν
1585, 1471, 1450, 1217, 1193, 736, 721; ESI-MS m/z
:
340.0 [M+H]+, 362.0 [M+Na]+; HRMS (ESI) calcd for
[M+H]+ C20H26N3O2: 340.2025, found: 340.2030.
Ethyl 3-(1
H-indol-3-yl)-1-propyl-1H-pyrazole-5-
carboxylate (8)
1
1-Propyl-3-(1-propyl-1H-indol-3-yl)-1H-pyrazole-5-
Off-white solid, yield 69%; m.p. 115.4-115.8oC; H-
carboxylic acid (5c)
NMR (600 MHz, DMSO-d6
= 7.2 Hz, 3H, OCH2CH3),
= 6.9 Hz,
) δ: 0.89 (t, J = 7.2 Hz, 3H,
1
Off-white solid, yield 93%; m.p. 158.5-159.5oC; H- CH2CH2CH3), 1.34 (t,
J
NMR (600 MHz, DMSO-d6
)
δ
: 0.75~0.79 (m, 6H, 1.83~1.86 (m, 2H, CH2CH2CH3), 4.34 (q,
J

346
D. Zhang et al.
2H, OCH2CH3), 4.51 (t,
J
= 6.9 Hz, 2H, CH2CH2CH3), dried (Na2SO4) and concentrated in vacuo. The
7.09 (t,
ArH), 7.19 (s, 1H, 4-H), 7.41 (d,
7.85 (d, = 2.4 Hz, 1H, IndH), 8.14 (d,
ArH); IR (KBr,
/cm-1) 3322, 3057, 2962, 2931, 1692,
1515, 1265, 1214, 1093, 758, 738.
J
= 7.5 Hz, 1H, ArH), 7.14 (t,
= 8.4 Hz, 1H, ArH), chromatography (silica gel, PE/EtOAc) to give a light
= 7.8 Hz, 1H, yellow solid (0.35 g, 48%).
J = 7.2 Hz, 1H, resulting yellow residue was purified by flash column
J
J
J
ν
Ethyl 1-(4-fluorobenzyl)-3-(1H-indol-3-yl)-1H-pyra-
zole-5-carboxylate (12)
1
Ethyl 3-(1
carboxylate (9)
Off-white solid, yield 13%; m.p. 137.8-138.0oC; H- OCH2CH3), 4.29 (q,
NMR (600 MHz, DMSO-d6 : 0.74 (t, = 7.5 Hz, 3H, (s, 2H, CH2Ph), 7.08~7.18 (m, 4H, ArH), 7.27~7.31 (m,
CH2CH2CH3), 1.31 (t, = 7.2 Hz, 3H, OCH2CH3), 3H, ArH, 4-H), 7.40 (d, = 7.6 Hz, 1H, ArH), 7.90 (d,
1.72~1.75 (m, 2H, CH2CH2CH3), 4.17 (t, = 6.9 Hz, = 2.4 Hz, 1H, IndH), 8.15 (d, = 8.0 Hz, 1H, ArH);
2H, CH2CH2CH3), 4.30 (q, = 7.2 Hz, 2H, OCH2CH3), IR (KBr,
/cm-1) 3266, 3068, 2977, 1712, 1578, 1509,
6.82 (s, 1H, 4-H), 7.11 (t, = 7.5 Hz, 1H, ArH), 7.20 (t, 1459, 1263, 1216, 747.
= 7.5 Hz, 1H, ArH), 7.49 (dd, = 4.2, 8.4 Hz, 2H,
= 3.0 Hz, 1H, IndH); IR (KBr,
/cm-1)
H
-indol-3-yl)-2-propyl-1
H
-pyrazole-5- Light yellow solid, yield 48%; m.p. 111.6-111.7oC; H-
NMR (400 MHz, DMSO-d6
) δ: 1.29 (t, J = 7.0 Hz, 3H,
1
J
= 7.2 Hz, 2H, OCH2CH3), 5.74
)
δ
J
J
J
J
J
J
J
ν
J
J
J
ArH), 7.67 (d,
3220, 2452, 1710, 1575, 1435, 1220, 1180, 1062, 755, 721.
J
ν
The general procedure for compounds (13-21)
To a solution of compound (1.01 mmol) in dried
6
DMF (3 mL), NaH (1.11 mmol, 60%) was added in
portions. The mixture thus obtained was stirred for 10
min at a temperature below 10oC; CH3I (1.21 mmol)
Ethyl 3-(1
pyrazole-5-carboxylate (10)
H-indol-3-yl)-1-(4-methoxybenzyl)-1H-
1
Slightly yellow oil, yield 65%; H-NMR (400 MHz, was then added, and the stirring was continued for
DMSO-d6 : 1.31 (t, = 7.2 Hz, 3H, OCH2CH3), 4.32 another 1 h at room temperature.. The mixture was
(q, = 7.2 Hz, 2H, OCH2CH3), 5.69 (s, 2H, CH2Ph), poured into water and extracted with CH2Cl2 (3 20
= 8.8 Hz, 2H, ArH), 7.08~7.16 (m, 2H, ArH), mL). The combined organic layers were then washed
= 8.4 Hz, 2H, ArH), 7.25 (s, 1H, 4-H), 7.41 (d, with water, dried over Na2SO4 and evaporated on a
= 2.0 Hz, 1H, IndH), rotary evaporator. The crude product was purified by
)
δ
J
J
×
6.89 (d,
7.23 (d,
J
J
J
= 8.0 Hz, 1H, ArH), 7.88 (d,
8.16 (d,
[M+1]+, 398.0 [M+23]+; IR (KBr,
2955, 1725, 1618, 1513, 1455, 1245, 1095, 985.
J
J
= 8.4 Hz, 1H, ArH); ESI-MS m/z: 376.0 silica gel column chromatography to give compound 13
.
ν
/cm-1) 3356, 3024,
Ethyl 1-benzyl-3-(1-methyl-1H-indol-3-yl)-1H-pyra-
zole-5-carboxylate (13)
1
Ethyl 1-(3,4-dimethoxybenzyl)-3-(1
-pyrazole-5-carboxylate (11)
White powder, yield 71%; m.p. 131.1-131.8ºC; 1H- OCH2CH3), 3.82 (s, 3H, CH3), 4.31 (q,
NMR (600 MHz, DMSO-d6 : 1.32 (t, = 7.2 Hz, 3H,
OCH2CH3), 3.70 (s, 3H, OCH3), 3.72 (s, 3H, OCH3), ArH), 7.20~7.24 (m, 4H, ArH, 4-H), 7.25~7.26 (m, 1H,
4.33 (q, = 7.2 Hz, 2H, OCH2CH3), 5.69 (s, 2H, ArH), 7.32~7.35 (m, 2H, ArH), 7.47 (d, = 8.4 Hz, 1H,
CH2Ph), 6.75 (dd, = 1.8, 8.4 Hz, 1H, ArH), 6.89 (d, ArH), 7.88 (s, 1H, IndH), 8.14 (d, = 7.8 Hz, 1H,
= 3.0 Hz, 1H, ArH), 7.01 (d,
= 1.8 Hz, 1H, ArH), 7.09 ArH); ESI-MS m/z: 359.8 [M+1]+, 381.8 [M+23]+; IR
(t, = 7.2 Hz, 1H, ArH), 7.13~7.16 (m, 1H, ArH), 7.25 (KBr,
/cm-1) 3049, 2972, 2929, 1710, 1583, 1458,
(s, 1H, 4-H), 7.42 (d, = 8.4 Hz, 1H, ArH), 7.88 (d, 1269, 1094, 739, 723.
2.4 Hz, 1H, IndH), 8.19 (d, = 7.8 Hz, 1H, ArH); IR
(KBr,
/cm-1) 3393, 3081, 2994, 2954, 2898, 1689, Ethyl 3-[1-(4-fluorobenzyl)-1
H
-indol-3-yl)- Light yellow solid, yield 69%; m.p. 139.5-141oC; H-
1
H
NMR (600 MHz, DMSO-d6
)
δ
: 1.29 (t,
J
J
= 6.9 Hz, 3H,
= 7.2 Hz, 2H,
)
δ
J
OCH2CH3), 5.77 (s, 2H, CH2Ph), 7.12~7.15 (m, 1H,
J
J
J
J
J
J
J
ν
J
J =
J
ν
H
-indol-3-yl]-1-pro-
1590, 1515, 1454, 1264, 1236, 1096, 768, 737.
pyl-1
Slightly brown oil, yield 87%; H-NMR (600 MHz,
DMSO-d6 : 0.89 (t, = 7.5 Hz, 3H, CH2CH2CH3),
= 7.2 Hz, 3H, OCH2CH3), 1.83~1.86 (m, 2H,
mmol) and 4-fluorobenzyl bromide (0.416 g, 2.2 mmol) CH2CH2CH3), 4.34 (q, = 7.2 Hz, 2H, OCH2CH3),
were mixed in dried CH3CN (10 mL), and the 4.51 (t, = 7.2 Hz, 2H, CH2CH2CH3), 5.43 (s, 2H,
resulting reaction mixture was refluxed for 5 h. The CH2Ph), 7.12~7.18 (m, 5H, ArH, 4-H), 7.33 (dd,
mixture was cooled to ambient temperature, poured 5.7, 8.1 Hz, 2H, ArH), 7.53 (d, = 8.4 Hz, 1H, ArH),
into water and extracted with CH2Cl2 (3 20 mL). 8.04 (s, 1H, IndH), 8.15 (d, = 8.4 Hz, 1H, ArH); IR
The combined organic layers were washed with water, (KBr,
/cm-1) 3405, 3045, 2966, 2935, 1702, 1585,
H-pyrazole-5-carboxylate (14)
1
)
δ
J
The procedure for compound (12)
Compound
3 (0.51 g, 2 mmol), K2CO3 (0.3 g, 2.2 1.34 (t, J
J
J
J
=
J
×
J
ν

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
347
1570, 1469, 1275, 1243, 1095, 1077, 765, 742, 730.
(m, 2H, ArH), 7.13 (t,
J
= 7.2 Hz, 1H, ArH), 7.18~7.19
(m, 1H, ArH), 7.20~7.23 (m, 3H, ArH, 4-H), 7.51 (d,
J
Ethyl 3-[1-(4-methoxybenzyl)-indol-3-yl]-1-pro- = 7.8 Hz, 1H, ArH), 7.93 (s, 1H, IndH), 8.16 (d,
pyl-1 -pyrazole-5-carboxylate (15) Hz, 1H, ArH); IR (KBr,
Colorless oil, yield 90%; H-NMR (400 MHz, DMSO- 1516, 1267, 1240, 1095, 815, 742.
d6 : 0.88 (t, = 8.4 Hz, 3H, CH2CH2CH3), 1.34 (t,
7.2 Hz, 3H, OCH2CH3), 1.81~1.87 (m, 2H, CH2CH2CH3), Ethyl 1-(3,4-dimethoxybenzyl)-3-(1-propyl-1
3.69 (s, 3H, OCH3), 4.35 (q, = 7.2 Hz, 2H, OCH2CH3), -3-yl)-1 -pyrazole-5-carboxylate (19)
5.35 (s, 2H, CH2Ph), 6.87 (d,
= 8.4 Hz, 2H, ArH), White solid, yield 79%; m.p. 128.8-129.3oC; H-NMR
7.10~7.17 (m, 3H, ArH, 4-H), 7.24 (d, = 8.4 Hz, 2H, (600 MHz, DMSO-d6 : 0.85 (t, = 7.5 Hz, 3H,
ArH), 7.53 (d, = 8.4 Hz, 1H, ArH), 8.00 (s, 1H, IndH), CH2CH2CH3), 1.32 (t, = 7.2 Hz, 3H, OCH2CH3),
8.13 (d, = 7.8 Hz, 1H, ArH); IR (KBr,
/cm-1) 3004, 1.79~1.83 (m, 2H, CH2CH2CH3), 3.70 (s, 3H, OCH3),
2955, 2900, 1740, 1600, 1520, 1480, 1280, 1100, 820, 3.72 (s, 3H, OCH3), 4.16 (t, = 6.9 Hz, 2H,
= 7.2 Hz, 2H, OCH2CH3),
5.68 (s, 2H, CH2Ph), 6.74 (dd, = 2.1, 8.1 Hz, 1H,
-indol-3-yl]- ArH), 6.89 (d, = 7.8 Hz, 1H, ArH), 7.01 (d, = 2.4
Hz, 1H, ArH), 7.10~7.13 (m, 1H, ArH), 7.17~7.20 (m,
J
= 7.8
H
ν
/cm-1) 3103, 2957, 2935, 1700,
1
)
δ
J
J =
H-indol
J
H
1
J
J
)
δ
J
J
J
J
ν
J
760.
CH2CH2CH3), 4.33 (q, J
J
Ethyl 3-[1-(3,4-dimethoxybenzyl)-1
H
J
J
1-propyl-1
Light yellow oil, yield 71%; 1H-NMR (600 MHz, 1H, ArH), 7.22 (s, 1H, 4-H), 7.52 (d,
DMSO-d6 : 0.89 (t, = 7.5 Hz, 3H, CH2CH2CH3), ArH), 7.93 (s, 1H, IndH), 8.18 (d,
1.34 (t, = 6.9 Hz, 3H, OCH2CH3), 1.82~1.86 (m, 2H, ArH); IR (KBr,
CH2CH2CH3), 3.69 (s, 3H, OCH3), 3.71 (s, 3H, OCH3), 1692, 1518, 1464, 1423, 1140, 1028, 766, 748.
4.33 (q, = 7.2 Hz, 2H, OCH2CH3), 4.50 (t, = 7.2 Hz,
2H, CH2CH2CH3), 5.33 (s, 2H, CH2Ph), 6.77 (dd,
1.8, 8.4 Hz, 1H, ArH), 6.87 (d, = 8.4 Hz, 1H, ArH), oxoethyl)-1
7.03 (d, = 2.4 Hz, 1H, ArH), 7.11~7.13 (m, 1H, ArH), ylate (20)
7.15~7.18 (m, 2H, ArH, 4-H), 7.55 (d,
ArH), 8.01 (s, 1H, IndH), 8.13 (d,
ArH); IR (KBr,
/cm-1) 2995, 2830, 1720, 1580, 1520, OCH2CH3), 1.32 (t,
H-pyrazole-5-carboxylate (16)
J
= 8.4 Hz, 1H,
)
δ
J
J = 7.8 Hz, 1H,
J
ν
/cm-1) 3140, 3084, 3001, 2931, 2872,
J
J
J
=
Ethyl 1-(3,4-dimethoxybenzyl)-3-[1-(2-ethoxy-2-
J
H-indol-3-yl]-1H-pyrazole-5-carbox-
J
1
J
= 8.4 Hz, 1H, White solid, yield 78%; m.p. 95.0-95.8oC; H-NMR
J
= 7.8 Hz, 1H, (600 MHz, DMSO-d6
)
δ
: 1.22 (t,
= 7.2 Hz, 3H, OCH2CH3), 3.70
(s, 3H, OCH3), 3.72 (s, 3H, OCH3) , 4.16 (q, = 7.2 Hz,
2H, OCH2CH3), 4.33 (q, = 7.2 Hz, 2H, OCH2CH3),
-indol-3-yl]- 5.16 (s, 2H, CH2COO), 5.69 (s, 2H, CH2Ph), 6.74 (dd,
= 1.8, 8.4 Hz, 1H, ArH), 6.90 (d, = 8.4 Hz, 1H,
Light yellow oil, yield 81%; H-NMR (600 MHz, ArH), 7.00 (d, = 1.8 Hz, 1H, ArH), 7.14~7.16 (m, 1H,
DMSO-d6 : 0.73 (t, = 7.5 Hz, 3H, CH2CH2CH3), ArH), 7.19~7.21 (m, 2H, ArH, 4-H), 7.44 (d, = 8.4 Hz,
1.31 (t, = 6.9 Hz, 3H, OCH2CH3), 1.71~1.75 (m, 2H, 1H, ArH), 7.86 (s, 1H, IndH), 8.18 (d, = 7.2 Hz, 1H,
CH2CH2CH3), 3.69 (s, 3H, OCH3), 3.71 (s, 3H, OCH3), ArH); IR (KBr,
/cm-1) 3005, 2915, 2700, 1765, 1720,
4.19 (t, = 6.9 Hz, 2H, CH2CH2CH3), 4.30 (q, = 7.2 1595, 1525, 1495, 1275, 1245, 1195, 1095, 1080, 745.
Hz, 2H, OCH2CH3), 5.41 (s, 2H, CH2Ph), 6.81~6.82
(m, 1H, ArH), 6.84 (s, 1H, 4-H), 6.88 (d, = 8.4 Hz, Ethyl 1-(4-fluorobenzyl)-3-(1-propyl-1
1H, ArH), 7.04 (d, = 1.2 Hz, 1H, ArH), 7.13 (t, yl)-1 -pyrazole-5-carboxylate (21)
7.5 Hz, 1H, ArH), 7.22 (t,
(d, = 8.4 Hz, 1H, ArH), 7.62 (d,
7.90 (s, 1H, IndH); IR (KBr,
/cm-1) 3100, 2980, 2965, CH2CH2CH3), 1.29 (t,
1715, 1595, 1520, 1460, 1220, 1095, 1025, 745. 1.72~1.82 (m, 2H, CH2CH2CH3), 4.14 (t,
2H, CH2CH2CH3), 4.30 (q, = 7.2 Hz, 2H, OCH2CH3),
-indol-3- 5.74 (s, 2H, CH2Ph), 7.09~7.19 (m, 4H, ArH), 7.24 (s,
1H, 4-H), 7.27~7.30 (m, 2H, ArH), 7.50 (d, = 8.0 Hz,
Off-white solid, yield 82%; m.p. 104.4-105.1oC; H- 1H, ArH), 7.93 (s, 1H, IndH), 8.14 (d,
= 7.6 Hz, 1H,
NMR (600 MHz, DMSO-d6 : 0.85 (t, = 7.2 Hz, 3H, ArH); IR (KBr,
/cm-1) 3045, 2966, 2935, 2877, 1715,
CH2CH2CH3), 1.31 (t, = 7.2 Hz, 3H, OCH2CH3), 1.80 1581, 1511, 1465, 1270, 1221, 1093, 810, 744.
(q, = 7.2 Hz, 2H, CH2CH2CH3), 3.70 (s, 3H, OCH3),
4.15 (t, = 7.2 Hz, 2H, CH2CH2CH3), 4.31 (q, = 7.2
Hz, 2H, OCH2CH3), 5.69 (s, 2H, CH2Ph), 6.88~6.90
J = 7.2 Hz, 3H,
ν
J
1460, 1265, 1080, 1020, 725.
J
J
Ethyl 3-[1-(3,4-dimethoxybenzyl)-1
H
2-propyl-1
H
-pyrazole-5-carboxylate (17)
J
J
1
J
)
δ
J
J
J
J
ν
J
J
J
H-indol-3-
J
J
=
H
1
J
= 7.5 Hz, 1H, ArH), 7.51 White solid, yield 72%; m.p. 85.7-86.4oC; H-NMR
J
J
= 8.4 Hz, 1H, ArH), (400 MHz, DMSO-d6
)
δ
J
: 0.84 (t,
= 7.2 Hz, 3H, OCH2CH3),
= 6.8 Hz,
J = 7.4 Hz, 3H,
ν
J
J
Ethyl 1-(4-methoxybenzyl)-3-(1-propy-1
H
yl) -1 -pyrazole-5-carboxylate (18)
H
J
1
J
)
δ
J
ν
J
J
J
J
The general procedure for compounds (22-32)
The title compounds were prepared as described for

348
D. Zhang et al.
compound 5a and the crude products were purified by 1077, 765, 742, 730; ESI-MS m/z: 378.0 [M+H]+;
silica gel column chromatography to give the target HRMS (ESI) calcd for [M+H]+ C22H21FN3O2: 378.1618,
products in good yields.
found: 378.1621.
1-Benzyl-3-(1H-indol-3-yl)-1H-pyrazole-5-carbox- 3-[1-(4-Methoxybenzyl)-1H-indol-3-yl]-1-propyl-
ylic acid (22)
1H-pyrazole-5-carboxylic acid (26)
1
1
Light yellow solid, yield 98%; m.p. 216.1-216.5oC; H- White solid, yield 97%; m.p. 172.6-173.2oC; H-NMR
NMR (600 MHz, DMSO-d6
7.09 (t, = 7.5 Hz, 1H, ArH), 7.14 (t,
ArH), 7.21~7.27 (m, 4H, ArH, 4-H), 7.34 (t,
2H, ArH), 7.41 (d, = 8.4 Hz, 1H, ArH), 7.86 (d,
1.2 Hz, 1 H, IndH), 8.14 (d, = 8.4 Hz, 1H, ArH); IR ArH), 7.09~7.12 (m, 2H, ArH, 4-H), 7.14~7.17 (m, 1H,
(KBr, = 8.4 Hz, 2H, ArH), 7.52 (d, = 8.4
/cm-1) 3412, 3030, 2944, 1710, 1588, 1472, ArH), 7.23 (d,
1248, 1103, 739; ESI-MS m/z: 317.7 [M+H]+, 339.7 Hz, 1H, ArH), 7.97 (s, 1H, IndH), 8.12 (d,
= 7.8 Hz,
[M+Na]+; HRMS (ESI) calcd for [M+H]+ C19H16N3O2: 1H, ArH); IR (KBr, /cm-1) 3417, 3000, 2962, 1699,
318.1242, found: 318.1230. 1586, 1472, 1245, 1029, 766, 739, 722; ESI-MS m/z
390.0 [M+H]+; HRMS (ESI) calcd for [M+H]+
-pyrazole-5-carbox- C23H24N3O3: 390.1817, found: 390.1805.
)
δ
: 5.79 (s, 2H, CH2Ph), (600 MHz, DMSO-d6
)
δ
: 0.88 (t, J = 7.5 Hz, 3H,
J
J
= 7.8 Hz, 1H, CH2CH2CH3), 1.82~1.85 (m, 2H, CH2CH2CH3), 3.69
J
= 7.5 Hz, (s, 3H, OCH3), 4.51 (t,
J
= 7.2 Hz, 2H, CH2CH2CH3),
= 1.8, 6.6 Hz, 2H,
J
J
=
5.35 (s, 2H, CH2Ph), 6.86 (dd,
J
J
ν
J
J
J
ν
:
2-Benzyl-3-(1H-indol-3-yl)-1H
ylic acid (23)
Yellow solid, yield 94%; m.p. 231-235ºC; 1H-NMR 3-[1-(3,4-Dimethoxybenzyl)-1
H
-indol-3-yl]-1-pro-
-pyrazole-5-carboxylic acid (27)
= 7.2 White solid, yield 96%; m.p. 163.2-163.5oC; H-NMR
= 7.5 Hz, 1H, ArH), 7.24 (d, (600 MHz, DMSO-d6 : 0.88 (t, = 7.2 Hz, 3H,
= 7.2 Hz, 1H, ArH), 7.30 (t, = 7.5 Hz, 2H, ArH), 7.47 CH2CH2CH3), 1.82~1.87 (m, 2H, CH2CH2CH3), 3.68
(m, 2H, ArH, IndH), 7.55 (d, = 7.8 Hz, 1H, ArH); IR (s, 3H, OCH3), 3.71 (s, 3H, OCH3), 4.51 (t, = 7.2 Hz,
(KBr,
/cm-1) 3323, 2961, 2930, 1692, 1548, 1515, 1463, 2H, CH2CH2CH3), 5.34 (s, 2H, CH2Ph), 6.76 (dd,
1247, 1093, 744; ESI-MS m/z: 318.0 [M+H]+, 340.0 2.1, 8.1 Hz, 1H, ArH), 6.86 (d,
= 7.8 Hz, 1H, ArH),
[M+Na]+; HRMS (ESI) calcd for [M+H]+ C19H16N3O2: 7.03 (d,
= 1.2 Hz, 1H, ArH), 7.10~7.12 (m, 2H, ArH,
318.1242, found: 318.1230. 4-H), 7.17 (t, = 7.5 Hz, 1H, ArH), 7.54 (d, = 8.4 Hz,
1H, ArH), 7.97 (s, 1H, IndH), 8.13 (d, = 8.4 Hz, 1H,
ArH); IR (KBr,
/cm-1) 3405, 3041, 2965, 2936, 2835,
1694, 1518, 1448, 1267, 1020, 806, 761, 738; ESI-MS
(600 MHz, DMSO-d6
1H, 4-H), 7.00 (d, = 7.8 Hz, 2H, ArH), 7.11 (t,
Hz, 1H, ArH), 7.20 (t,
) δ: 5.51 (s, 2H, CH2Ph), 6.91 (s, pyl-1H
1
J
J
J
J
)
δ
J
J
J
J
ν
J =
J
J
J
J
J
1-Benzyl-3-(1-methyl-1
H
-indol-3-yl)-1
H
-pyrazole-
ν
5-carboxylic acid (24)
Off-white solid, yield 93%; m.p. 200-203ºC; H-NMR m/z: 420.0 [M+H]+, 442.0 [M+Na]+; HRMS (ESI) calcd
1
(600 MHz, DMSO-d6
CH2Ph), 7.13 (t, = 7.5 Hz, 1H, ArH), 7.18 (s, 1H, 4-
H), 7.20~7.23 (m, 3H, ArH), 7.26 (t, = 6.9 Hz, 1H, 3-[1-(3,4-Dimethoxybenzyl)-1
ArH), 7.33 (t, = 7.5 Hz, 2H, ArH), 7.47 (d, = 7.8 Hz, pyl-1 -pyrazole-5-carboxylic acid (28)
1H, ArH), 7.84 (s, 1H, IndH), 8.13 (d,
= 8.4 Hz, 1H, White solid, yield 98%; m.p. 82.3-85.3oC; H-NMR
ArH); IR (KBr, : 0.73 (m, 3H, CH2CH2CH3),
/cm-1) 3100, 3036, 2937, 1687, 1580, (600 MHz, DMSO-d6
1533, 1469, 1246, 1098, 761, 723; ESI-MS m/z: 331.7 1.72~1.73 (m, 2H, CH2CH2CH3), 3.69 (s, 3H, OCH3),
[M+H]+, 353.7 [M+Na]+; HRMS (ESI) calcd for [M+H]+ 3.70 (s, 3H, OCH3), 4.17 (t,
= 7.2 Hz, 2H, CH2CH2CH3),
C20H18N3O2: 332.1399, found: 332.1392. 5.41 (s, 2H, CH2Ph), 6.81 (t, = 8.7 Hz, 2H, ArH), 6.88
(d, = 8.4 Hz, 1H, ArH), 7.04 (s, 1H, 4-H), 7.12 (t,
7.5 Hz, 1H, ArH), 7.21 (t, = 7.5 Hz, 1H, ArH), 7.50 (d,
= 7.8 Hz, 1H, ArH), 7.61 (d, = 8.4 Hz, 1H, ArH), 7.89
Off-white solid, yield 95%; m.p. 149oC; 1H-NMR (s, 1H, IndH); IR (KBr, /cm-1) 3390, 3052, 2961, 2933,
(600 MHz, DMSO-d6 : 0.88 (t, = 7.2 Hz, 3H, 2835, 1718, 1515, 1460, 1260, 1156, 1025, 743; ESI-
CH2CH2CH3), 1.81~1.87 (m, 2H, CH2CH2CH3), 4.51 MS m/z: 420.0 [M+H]+, 442.0 [M+Na]+; HRMS (ESI)
(t,
= 7.2 Hz, 2H, CH2CH2CH3), 5.43 (s, 2H, CH2Ph), calcd for [M+H]+ C24H26N3O4: 420.1923, found: 420.1912.
7.11~7.18 (m, 5H, ArH, 4-H), 7.30~7.33 (m, 2H, ArH),
7.51 (d, = 7.8 Hz, 1H, ArH), 8.00 (s, 1H, IndH), 8.13 1-(4-Methoxybenzyl)-3-(1-propyl-1
(d, = 7.8 Hz, 1H, ArH); IR (KBr, -pyrazole-5-carboxylic acid (29)
/cm-1) 3405, 3045,
) δ
: 3.81 (s, 3H, CH3), 5.78 (s, 2H, for [M+H]+ C24H26N3O4: 420.1923, found: 420.1920.
J
J
H-indol-3-yl]-2-pro-
J
J
H
1
J
ν
) δ
J
J
J
J =
3-[1-(4-Fluorobenzyl)-1
pyrazole-5-carboxylic acid (25)
H
-indol-3-yl]-1-propyl-1
H-
J
J
J
ν
)
δ
J
J
J
H
-indol-3-yl)-
J
ν
1H
2966, 2935, 1702, 1585, 1570, 1469, 1275, 1243, 1095, White powder, yield 96%; m.p. 197-198oC; H-NMR
1

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
349
(600 MHz, DMSO-d6
CH2CH2CH3), 1.80 (q,
3.70 (s, 3H, OCH3), 4.16 (t,
)
δ
: 0.85 (t,
= 7.2 Hz, 2H, CH2CH2CH3), 400.0 [M+Na]+; HRMS (ESI) calcd for [M+H]+
= 7.2 Hz, 2H, C22H21FN3O2: 378.1618, found: 378.1628.
CH2CH2CH3), 5.69 (s, 2H, CH2Ph), 6.89 (d, = 2.4 Hz,
2H, ArH), 7.12 (t, = 7.5 Hz, 1H, ArH), 7.16~7.23 (m,
4H, ArH, 4-H), 7.51 (d, = 7.8 Hz, 1H, ArH), 7.88 (s, 1-(1-Propyl-1
1H, IndH), 8.14 (d, = 7.8 Hz, 1H, ArH); IR (KBr,
J
= 7.2 Hz, 3H, 1243, 1029, 746, 737; ESI-MS m/z: 378.0 [M+H]+,
J
J
J
J
General procedure for compound (35)
-indol-3-yl) ethanone (33)
Compound 33 was synthesized according to a
J
H
J
ν/
cm-1) 3423, 3069, 3006, 2960, 2930, 2549, 1693, 1514, conventional method with DMF as the solvent and
1463, 1287, 1094, 763, 745; ESI-MS m/z: 390.0 NaH as the base in a yield of 90%.
[M+H]+, 412.0 [M+Na]+; HRMS (ESI) calcd for [M+H]+
C23H24N3O3: 390.1817, found: 390.1818.
Ethyl 2, 4-dioxo-4-(1-propyl-1H-indol-3-yl)buta-
noate (34, R = -propyl)
n
1-(3,4-Dimethoxybenzyl)-3-(1-propyl-1H-indol-3-
Sodium ethoxide (0.27 g, 4 mmol) was added to a
yl)-1
H
-pyrazole-5-carboxylic acid (30)
mixture of compound 33 (0.35 g, 1.7 mmol) and diethyl
1
White solid, yield 95%; m.p. 169.8-171.7oC; H-NMR oxalate (0.31 mL). After being stirred for 2 h at 75oC,
(600 MHz, DMSO-d6
CH2CH2CH3), 1.79~1.82 (m, 2H, CH2CH2CH3), 3.70 CH2Cl2 (3
(s, 3H, OCH3), 3.72 (s, 3H, OCH3), 4.15 (t, = 6.9 Hz, then washed with water, dried over Na2SO4, and
2H, CH2CH2CH3), 5.69 (s, 2H, CH2Ph), 6.73 (dd, evaporated under vacuum. The residue was purified
2.1, 8.1 Hz, 1H, ArH), 6.89 (d, = 8.4 Hz, 1H, ArH), on a short silica gel column chromatography to afford
7.01 (d, = 1.8 Hz, 1H, ArH), 7.09~7.12 (m, 1H, ArH), compound 34
7.16 (s, 1H, 4-H), 7.17~7.20 (m, 1H, ArH), 7.51 (d,
Yellow-green solid, yield 91%; m.p. 105.4-105.6oC; 1H-
8.4 Hz, 1H, ArH), 7.88 (s, 1H, IndH), 8.16 (d, = 8.4 NMR (400 MHz, DMSO-d6 : 0.85 (t, = 7.4 Hz, 3H,
Hz, 1H, ArH); IR (KBr, = 7.0 Hz, 3H, OCH2CH3),
/cm-1) 3140, 3001, 2931, 2872, CH2CH2CH3), 1.31 (t,
1692, 1518, 1464, 1285, 1140, 1028, 766, 748; ESI-MS 1.82~1.89 (m, 2H, CH2CH2CH3), 4.24 (t, = 7.2 Hz,
m/z: 420.1 [M+H]+, 442.0 [M+Na]+; HRMS (ESI) calcd 2H, CH2CH2CH3), 4.30 (q,
= 7.2 Hz, 2H, OCH2CH3),
for [M+H]+ C24H26N3O4: 420.1923, found: 420.1922.
6.98 (d, 1H, O=C-CH=COH), 7.26~7.33 (m, 2H, ArH),
7.66 (d, = 8.0 Hz, 1H, ArH), 8.23 (d, = 7.6 Hz, 1H,
-indol-3-yl]-1-(3, 4-dime- ArH), 8.80 (s, 1H, ArH); IR (KBr,
/cm-1) 3400, 2950,
-pyrazole-5-carboxylic acid (31) 2850, 1735, 1600, 1515, 1460, 1200, 1115, 750.
)
δ
: 0.85 (t,
J
= 7.5 Hz, 3H, the mixture was poured into water and extracted with
×
20 mL). The combined organic layers were
J
J
=
J
J
.
J
=
J
)
δ
J
ν
J
J
J
J
J
3-[1-(Carboxymethyl)-1
thoxybenzyl)-1
White solid, yield 93%; m.p. 225.5-225.6oC; H-NMR
(600 MHz, DMSO-d6 : 3.70 (s, 3H, OCH3), 3.72 (s, Ethyl 3-(1-propyl-1
3H, OCH3), 5.06 (s, 2H, CH2COO), 5.70 (s, 2H, carboxylate (major/minor = 65:35) (35, R =
CH2Ph), 6.73 (dd, = 1.8, 8.4 Hz, 1H, ArH), 6.89 (d, propyl)
= 8.4 Hz, 1H, ArH), 7.00 (d, = 1.8 Hz, 1H, ArH), Compound 35 was prepared analogously to com-
7.12~7.15 (m, 2H, ArH, 4-H), 7.18~7.20 (m, 1H, ArH), pound . White power, yield 96%; m.p. 186.4-186.6
= 8.4 Hz, 1H, ArH), 7.82 (s, 1H, IndH), 8.16 oC; H-NMR (400 MHz, DMSO-d6
: 0.87 (m, 3H,
= 7.2 Hz, 1H, ArH); IR (KBr,
/cm-1) 3440, 3094, CH2CH2CH3), 1.32 (m, 3H, OCH2CH3), 1.77~1.86 (m,
2951, 2932, 1725, 1669, 1680, 1587, 1467, 1263, 1243, 2H, CH2CH2CH3), 4.12~4.20 (m, 2H, CH2CH2CH3),
1217, 1029, 746, 737; ESI-MS m/z: 436.0 [M+H]+, 4.26~4.34 (m, 2H, OCH2CH3), 6.98 (d,
= 1.6 Hz,
458.0 [M+Na]+; HRMS (ESI) calcd for [M+H]+ 0.65H, ArH; the proton signal of the minor isomer
C23H22N3O6: 436.1508, found: 136.1495. was merged in 7.09~7.24 ppm), 7.09~7.24 (m, 2.35H,
ArH), 7.50/7.57 (d/d (35:65), = 8.4 Hz, 1H, ArH),
7.84/8.13 (d/d (65:35), = 8.0 Hz, 1H, ArH), 7.86/
7.89 (s/s (65:35), 1H, ArH); IR (KBr,
/cm-1) 3250,
H
ν
H
1
)
δ
H-indol-3-yl)-1H-pyrazole-5-
n-
J
J
J
3
1
7.43 (d,
(d,
J
) δ
J
ν
J
J
1-(4-Fluorobenzyl)-3-(1-propyl-1
H
-indol-3-yl)-1
H-
J
pyrazole-5-carboxylic acid (32)
ν
Off-white solid, yield 93%; m.p. 155oC; 1H-NMR 2950, 2855, 1720, 1620, 1430, 1245, 1080, 720.
(400 MHz, DMSO-d6) δ: 0.84 (t, J = 7.4 Hz, 3H,
CH2CH2CH3), 1.71~1.82 (m, 2H, CH2CH2CH3), 4.14 In vitro functional studies
(t,
J
= 6.8 Hz, 2H, CH2CH2CH3), 5.76 (s, 2H, CH2Ph),
Endothelin-1 antagonist activity of compounds was
7.07~7.18 (m, 5H, ArH, 4-H), 7.28 (t,
J
= 7.6 Hz, 2H, tested with isolated rat aortic rings with slight
ArH), 7.49 (d,
IndH), 8.11 (d,
J
J
= 8.0 Hz, 1H, ArH), 7.86 (s, 1H, modifications of the literature procedure (Jaiswal et
= 8.0 Hz, ArH); IR (KBr,
ν
/cm-1) al., 1991; Clozel et al., 1994). Male Sprague-Dawley
3440, 3094, 2951, 2932, 1725, 1669, 1587, 1467, 1263, rats (200-260 g) were anesthetized with uratine (1500

350
D. Zhang et al.
mg/kg i.p.) and the thoracic aorta was isolated and cut standards for comparison of antibacterial activities.
into 3-4 mm rings. Each ring was vertically fixed with All the synthesized compounds and positive drugs
two hooks in organ baths containing Krebs-Henseleit were dissolved separately to prepare a stock solution
(KH) solution (pH 7.4), which was maintained at 37oC of 2 mg/mL in DMSO. Four broth cultures were
and bubbled with a mixture of 95% O2 and 5% CO2. prepared using sterile peptone water containing one
The composition of the KH solution was as follows type of organism each from stock cultures. A sterile
(mM): NaCl 120, KCl 4.8, KH2PO4 1.2, NaHCO3 25, cotton swab was dipped into one of the broth cultures
Glucose 11, CaCl2 2.5, MgCl2 1.4 and EDTA 0.01. The and was used to inoculate a Mueller Hinton agar plate.
isometric force was recorded via a force displacement Filter paper discs (6 mm in diameter) impregnated
transducer connected to BL-420F Data Acquisition & with the newly synthesized compounds (50
µL, 100 µg)
Analysis System (TME Technology Co. Ltd). After a and positive drugs (5 L, 10 g) were picked and
µ
µ
60-min equilibration period with resting tension of placed on the agar plate. After incubation for 24 h at
1.2 g, the aortic rings were given two successive 37oC, the zones of inhibition on each plate were
stimulations with 60 mM KCl, washed with fresh examined and measured with a millimeter ruler
media and equilibrated until a stable baseline force across the disk. The diameter of the zone was recorded
was obtained. The rings were pre-stretched with ET-1 to the nearest whole millimeter.
(10 nM), and then cumulative doses of compound were
added in the media when the force reached a plateau. Statistical analysis
The antagonistic effects on exogenous ET-1-induced
vasoconstriction were calculated by the following analysis was done by ANOVA, and differences at
formula: Inhibition % = (The maximum vascular tone
< 0.05 were considered statistically significant.
before treatment with antagonist
vascular tone after
The results are expressed as means ± S.E. Statistical
p
−
treatment with antagonist) / (The maximum vascular
tone before treatment with antagonist – resting tone)
× 100%.
RESULTS AND DISCUSSION
The general strategies for the synthesis of the title
compounds are illustrated in Scheme 1, Scheme 2 and
In vivo studies: Prevention of ET-1 induced Scheme 3. The common intermediate
sudden death. according to a known procedure (Gorbunova and
ET-1 (10 nmol/kg) was injected into the tail vein of Suvorov, 1973). Compound consists of two tautomers,
3 was prepared
3
1
ICR mice (18-20 g) 4 h after intragastric administration in a ratio of 7:3 based on the H-NMR spectrum,
of the compounds and bosentan (100 mg/kg). The which was attributed to the tautomerism of the
number of dead mice was recorded within 20 min after pyrazole ring (Scheme 1). The structure with the
ET-1 infusion, and the mortality of mice was used to chemical name of ethyl 3-(1H-indol-3-yl)-1H-pyrazole-
evaluate the endothelin antagonist effects of tested 5-carboxylate was assigned as the major isomer
compounds (Ihara et al., 1992; Raschack et al., 1995).
(Jaronczyka et al., 2004; Brady et al., 2009). Inter-
mediates were obtained in a one-step reaction
through the alkylation reaction of in the presence of
4
Antibacterial activity: Kirby-Bauer’s Method
3
Antibacterial activity was measured with slight NaH (Scheme 2). The monosubstituted ester inter-
modifications of literature procedures (Prasda and mediates ( 11) were synthesized by alkylation of in
6-
3
Kishore, 2007). Four bacterial strains were used for the presence of KOH (1.2 equiv) and dry DMSO to
these tests: Staphylococcus aureus, Escherichia coli, give the N-1 substituted derivatives as the major
Bacillus subtilis and Bacillus thuringiensis. Ampicillin products, accompanied by the minor regioisomers
(AMP) and kanamycin (KNA) were selected as (Scheme 3). The two isomers (6 and 7, 8 and 9) could
Scheme 1. The synthetic route to compound 3.

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
351
be separated by flash chromatography on silica gel.
An alternative synthetic route is shown in Scheme
For compound 12, K2CO3 was used as the base with 4. If this method works, it will first block a reactive
CH3CN as the solvent. The monosubstituted intermediates site on the N atom of the indole ring before the
(6, 8-12) were easily converted into disubstituted construction of N-substituted pyrazole derivatives,
intermediates by alkylation with different halides, thus avoiding the generation of the disubstituted by-
and alkaline hydrolysis of the esters intermediates in products. When 1-bromopropane and 1-bromobutane
ethanol/H2O produced the target compounds (22
-32).
were employed, compound 34 was obtained and the
Scheme 2. Synthesis of compounds with the same substituents at the two nitrogen atoms of the indole and pyrazole rings.
Scheme 3. Synthesis of compounds with different substituents at the two nitrogen atoms of the indole and pyrazole rings.
Scheme 4. The alternative synthetic route.

352
D. Zhang et al.
subsequent cyclization with hydrazine and the the compounds with the N-CH3/N-CH2 resonating at
alkylation reaction were straightforward. However, lower fields in the 1H-NMR spectrum as the N-1
the reactions of compound 33 with various benzyl substituted regioisomers (
halides to produce the desired intermediate 34 were of the chemical shifts of these two regioisomers in
time-consuming, produced very low yields, or even Fig. . Consistent with previous reports, the major
e.g., 6). There is a comparison
2
failed. Considering this deficiency, we chose a reaction isomers had chemical shifts of 5.77 and 4.51 ppm
route in which the reactive site of the substitution (lower fields) for the CH2 attached to N-1 of the
1
reaction was selectable and controllable (Scheme 3).
pyrazole ring in their individual H-NMR spectra,
Some characteristics of the synthesized target while the minor isomers had chemical shifts of 5.51
compounds are outlined in Table I. Analytical and and 4.17 ppm (higher fields) for the CH2 attached to
spectral data (1H-NMR, HRMS and IR) confirmed the N-2 of the pyrazole ring. For compounds with the 3-
structures of the new compounds.
(1H-indol-3-yl)pyrazole-5-carboxylic acid nucleus, the
The structures of the N-1 and N-2 substituted CH2 of a certain substituent group adjacent to N-1 of
isomers (e.g., 6 and 7 in Fig. 2) were assigned pyrazole always had a higher chemical shift in the
according to the methods of Dodson and Zhou (Papesch 1H-NMR spectrum than that attached to the N atom
and Dodson, 1965; Brady et al., 2009). They assigned of indole (Fig. 3).
Table I. The characteristics of the synthesized target compounds
Compound
R1
Benzyl
n-butyl
n-propyl
Benzyl
Benzyl
Benzyl
n-propyl
n-propyl
R2
benzyl
n-butyl
R1 Substitution position
Mol. formula
C26H21N3O2
C20H25N3O2
C18H21N3O2
C19H15N3O2
C19H15N3O2
C20H17N3O2
C22H20FN3O2
C23H23N3O3
C24H25N3O4
C24H25N3O4
C23H23N3O3
C24H25N3O4
C23H21N3O6
C22H20FN3O2
Yield (%)
93
5a
5b
5c
22
23
24
25
26
27
28
29
30
31
32
N-1
N-1
N-1
N-1
N-2
N-1
N-1
N-1
N-1
N-2
N-1
N-1
N-1
N-1
96
93
98
94
93
95
97
96
98
96
95
93
n-propyl
H
H
Me
4-F-benzyl
4-MeO-benzyl
3, 4-Di-MeO-benzyl
3, 4-Di-MeO-benzyl
n-propyl
n-propyl
n-propyl
4-MeO-benzyl
3, 4-Di-MeO-benzyl
3, 4-Di-MeO-benzyl
4-F-benzyl
n-propyl
CH2COOH
n-propyl
93
Fig. 2. The chemical shift differences between the CH2 adjacent to N-1 and adjacent to N-2.
Fig. 3. The chemical shift differences between regioisomers.

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
353
Fig. 4. Antagonistic effect of tested compounds on the contraction induced by ET-1 (10 n M) in endothelium intact aortic
rings. Results are presented as means
± S.E., n = 5. *p < 0.05, **p < 0.01 vs Veh group. Veh, vehicle; bo, bosentan.
1
The H-NMR spectrum of the chemical shift of the comparison of the two regioisomers (22
/
23 and 27
/28),
C2 aromatic proton in the indole ring on the target it could be concluded that compounds with a
compounds showed a singlet peak at = 7.80~8.10 substituent adjacent to N-2 of the pyrazole ring were
δ
ppm, except for that of the monosubstituted products more active than their pyrazole N-1 substituted
22 and 23. The two aromatic proton signals in C4 and regioisomers in the in vitro experiments. Interestingly,
C7 positions of the indole moiety appeared among the analogues of 25
respectively at about = 7.50 ppm and 8.10 ppm as compounds 26 and 29 had marked inhibitory activity
doublets ( = 7.8~8.4 Hz). The C4 aromatic proton compared with the others, which meant that the 4-
signal of N-1 or N-2 substituted pyrazole moiety methoxybenzyl group was a beneficial functional
appeared at the range of = 7.10~7.30 ppm or substituent in this series of compounds. Replacement
-27, 29, 30 and 32,
δ
J
δ
δ =
6.80~7.00 ppm as a singlet peak, respectively. All the of the n-propyl group in compound 30 with a car-
other aromatic and active hydrogens were observed at boxymethyl group led to a great increase in the
the expected regions.
activity (31). In addition, swapping the position of
In the IR spectra of these compounds, a broad substituents adjacent to N-1 of pyrazole ring and 1-
absorption band around 1715 cm-1 indicated the position of indole ring had minor effects on the
presence of a carbonyl group in the compounds. The activity.
C-N single bond absorption in the pyrazole ring was
observed at about 1460 cm-1. Other prominent
Prevention of ET-1-induced sudden death.
absorption bands in the IR spectrum were observed
Systemic administration of ET-1 provokes sudden
death in mice and rats due to the potent activities of
around 3060 (Ar-H), 1580 (C=C) and 1110 (C-O) cm-1.
Further evidence for the formation of the target ET, i.e., vasoconstriction, bronchoconstriction and the
compounds was obtained by recording the high- release of active substances such as platelet activating
resolution mass spectra.
factor (Okumura et al., 1994, 1995). The model of ET-
1-induced sudden death was used to demonstrate the
ET antagonistic effects of the tested compounds. The
ET-1 antagonist activity
ET-1 antagonist effects of the compounds were results are summarized in Table II. ET-1 (10 nmol/kg,
determined in rat aorta rings with intact endothelium. i.v.) caused sudden death in mice (100%), and the
As shown in Fig. 4, in aortic rings preconstricted with mortality rates were reduced in the mice treated with
ET-1, the tested compounds induced dose-related compounds 4 h before the ET-1 injection. 5b showed
relaxation in the 0.1-10
concentration of 1 g/mL, compounds 23
29 showed relatively significant antagonistic activities than 5c
that were comparable to that of the positive control. benzyl ring with a withdrawing group at the 1-position
At the 10 g/mL level, most of the test compounds of indole ring was preferable for the in vivo activity.
were potent and the effects of 5b 5c, 26 and 28 were Replacement of the 3,4-dimethoxybenzyl group in
comparable to that of bosentan. The activity of compound 30 with a 4-fluoro/methoxybenzyl group led
compound 22 was less than that of 5a and 24 to a large loss of activity (29 and 32). These results
µ
g/mL dose range. At the comparable activity with bosentan, and 30 was more
24 28 and potent than bosentan. Compound 25 was more potent
26 and 27, indicating that a para-substituted
µ
,
,
,
µ
,
,
indicating that disubstituted derivatives were more imply that the nature and the position of substituents
potent than monosubstituted derivatives. Upon on the benzyl group may play an important role in

354
D. Zhang et al.
Table II. Prevention of ET-1-induced sudden death in mice
thuringiensis and the gram-negative Escherichia coli
species using Kirby-Bauer’s Method. Ampicillin and
kanamycin were used as positive controls. Bacteria
were exposed to the potential antibacterial in Mueller
Hinton agar. After overnight incubation, inhibition
zones were measured (Table III). Most of the compounds
exhibited weak activity against these bacteria
compared to standard drugs. Compounds 25 and 26
were more active than other compounds, indicating
that further optimization could be carried out to
obtain analogues with better antibacterial activity.
Methods for the synthesis of novel compounds
Number of
samples
Number of
deaths
Mortality
rate %
Compound
5a
5b
5c
22
23
24
25
26
27
28
29
30
31
11
10
8
11
7
11
7
6
7
7
7
7
7
3
4
8
4
7
3
3
4
4
3
1
4
7
10
2
63.6
30.0*
50.0
72.7
57.1
63.6
42.9
50.0
57.1
57.1
42.9
14.3**
57.1
100.0
100.0
28.6
bearing a 3-(1H-indol-3-yl)pyrazole-5-carboxylic acid
nucleus and the determination of the regioisomers
were demonstrated. The endothelin-1 antagonistic
activities, antibacterial activities and structure activity
relationship (SAR) of the newly synthesized compounds
were provided. In the in vitro experiments, compounds
7
7
10
7
32
vehicle
bosentan
23, 24, 28 and 29 exhibited significant antagonistic
*The tested compound showed comparable activity with effects at 1
µg/mL and compounds 5b, 5c, 26 and 28
bosentan.
were as potent as bosentan at high concentration. In
the in vivo experiments, 5b showed comparable activity
with bosentan, and 30 was more potent than bosentan.
**The tested compound was more potent than Bosentan.
determining the in vivo endothelin-1 antagonistic For the tested compounds, there were differences
activity.
between the in vitro and in vivo endothelin-1 an-
tagonistic activities. This may be due to differences in
solubility, distribution and metabolic pathways among
Antibacterial evaluation
Antibacterial activity of the synthesized compounds the different compounds, and further studies are
was determined against the gram-positive organisms needed to elucidate the pharmacodynamic properties
Staphylococcus aureus, Bacillus subtilis, and Bacillus of these compounds. The antibacterial trial demon-
strated that some of the tested compounds showed
weak antibacterial activity. These preliminary results
are beneficial for further lead optimization.
Table III. Overview of the antibacterial activities of target
compounds (100
Compound
µg) and selected reference compounds (10 µg)
Zone of inhibition (mm)
ACKNOWLEDGEMENTS
Bacillus
Bacillus
S. aureus
E. coli
subtilis thuringiensis
This research was supported by the Foundation for
Outstanding Young Scientist in Shandong Province
(BS2009SW032) and the Natural Science Foundation
of Shandong Province (2009ZRB01128). We thank
Professor J. H. Ju (South China Sea Institute of
Oceanology, Chinese Academy of Sciences) for the
antibacterial study and for his helpful advice.
5a
5b
5c
22
23
24
25
26
11
7
-
-
8
8
7
13.5
7.5
7
-
-
8
9
-
6.5
14
12
-
-
8
7
-
7
9
8
8
-
7.5
7
12
12.5
7.5
-
7
13
11
7
REFERENCES
27
28
7
7
Abdel-Aziz, M., Abuo-Rahma, G., El-Din. A., and Hassan, A.
A., Synthesis of novel pyrazole derivatives and evaluation
of their antidepressant and anticonvulsant activities.
Eur. J. Med. Chem., 44, 3480-3487 (2009).
Akbas, E., Berber, I., Sener, A., and Hasanov, B., Synthesis
and antibacterial activity of 4-benzoyl-1-methyl-5-phenyl-
29
30
31
32
KNA
8
7
-
-
16
20.5
8
7
-
7
25
32
9
7
-
6.5
22
29
11.5
7
-
-
25
13.5
AMP
1H-pyrazole-3-carboxylic acid and derivatives. Farmaco,
-: no activity.

3-(1H-indol-3-yl)pyrazole-5-carboxylic Acid Derivatives
355
60, 23-26 (2005).
Basavarajaiah, S. D. M. and Mruthyunjayaswamy, B. H. M.,
Synthesis and antimicrobial activity of some5-substituted-
Kobayashi, F., and Matsuura, A., Possible mechanisms of
sudden death and hemoconcentration induced by
endothelin-1 and big endothelin-1 in mice. Biol. Pharm.
Bull., 17, 645-650 (1994).
3-phenyl-Nβ-(substituted-2-oxo-2
H-pyrano[2,3-b]quinoline-
3-carbonyl)-1 -indole-2-carboxyhydrazide. Chem. Pharm.
Bull., 57, 557-560 (2009).
Brady, T., Vu, K., Barber, J. R., Ng, S. C., and Zhou, Y. F.,
Synthesis of novel 2,3-substituted-2,4-dihydro-pyrazolo
[4,3-d]pyrimidine-5,7-diones. Tetrahedron Lett., 50, 6223-
H
Okumura, H., Ashizawa, N., Asakura, R., Aotsuka, T.,
Kobayashi, F., and Matsuura, A., Possible involvement of
different mechanisms in sudden death induced by
endothelin-1 and big endothelin-1. Biol. Pharm. Bull., 18,
18-23 (1995).
6227 (2009).
Papesch, V. and Dodson, R. M., Isomeric pyrazolo[4,3-
d]pyrimidinediones. J. Org. Chem., 30, 199-203 (1965).
Prasda, M. R. and Kishore, D. P., Multistep, microwave
assisted, solvent free synthesis and antibacterial activity
Clozel, M., Breu, V., Gray, G. A., Kalina, B., Löffler, B. M.,
Burri, K., Cassal, J. M., Hirth, G., Müller, M., and
Neidhart, W., Pharmacological characterization of Bosentan,
a new potent orally active nonpeptide endothelin receptor
antagonist. J. Pharmacol. Exp. Ther., 270, 228-235 (1994).
EI-Sabbagh, O. I., Baraka, M. M., Ibrahim, S. M.,
Pannecouque, C., Andrei, G., Snoeck, R., Balzarini, J., and
Rashad, A. A., Synthesis and antiviral activity of new
pyrazole and thiazole derivatives. Eur. J. Med. Chem., 44,
3746-3753 (2009).
of 6-substituted-2,3,4-trihydropyrimido[1,2-
tetrahydrobenzo[ ]thieno[3,2- ] pyrimidines. Chem. Pharm.
Bull., 55, 776-779 (2007).
c]9,10,11,12-
b
e
Raschack, M., Unger, L., Riechers, H., and Klinge, D.,
Receptor selectivity of endothelin antagonists and
prevention of vasoconstriction and endothelin-induced
sudden death.
J. Cardiovasc. Pharmacol., 26 Suppl 3,
Gorbunova, V. P. and Suvorov, N. N., Indoles derivatives
LXXXIX. Synthesis of some diketo esters of the indole
series and of indolypyrazoles from them. Khim. Geterotsikl.
Soedin., 11, 1519-1522 (1973).
Ihara, M., Noguchi, K., Saeki, T., Fukuroda, T., Tsuchida, S.,
Kimura, S., Fukami, T., Ishikawa, K., Nishikibe, M., and
Yano, M., Biological profiles of highly potent novel
endothelin antagonists selective for the ETA receptor. Life
Sci., 50, 247-255 (1992).
S397-S399 (1995).
Rawson, D. J., Dack, K. N., Dickinson, R. P., and James, K.,
The design and synthesis of a novel series of indole
derived selective ETA antagonists. Bioorg. Med. Chem.
Lett., 12, 125-128 (2002).
Shawali1, A. S., Sherif, S. M., Darwish, M. A. A., and El-
merzabani, M. M., Synthesis and antitumor screening of
new 1,7-diphenyl-3-(1,3-disubstituted-1
bonyl)-[1,2,4]triazolo[4,3- ] pyrimidin-5(1
Pharm. Res., 33, 647-654 (2010).
Singh, N., Bhati, S. K., and Kumar, A., Thiazolyl/oxazolyl
formazanyl indoles as potent anti-inflammatory agents.
Eur. J. Med. Chem., 43, 2597-2609 (2008).
H
-pyrazole-4-car-
a
H
)-ones. Arch.
Jaiswal, N., Lambrecht, G., Mutschler, E., Tacke, R., and
Malik, K. U., Pharmacological characterization of the
vascular muscarinic receptors mediating relaxation and
contraction in Rabbit Aorta. J. Pharmacol. Exp. Ther.
,
258, 842-850 (1991).
Jaronczyka, M., Dobrowolski, J. C., and Mazureka, A. P.,
Theoretical studies on tautomerism and IR spectra of
Yamamoto, Y. and Kurazono, M., A new class of anti-MRSA
and anti-VRE agents: preparation and antibacterial
activities of indole-containing compounds. Bioorg. Med.
Chem. Lett., 17, 1626-1628 (2007).
pyrazole derivatives. J. Mol. Struct. (Theochem), 673, 17-
28 (2004).
Zhang, J., Didierlaurent, S., Fortin, M., Lefrancois, D.,
Uridata, E., and Veverta, J. P., Potent nonpeptide
endothelin antagonists: Synthesis and structure-activity
relationships of pyrazole-5-carboxylic acids. Bioorg. Med.
Chem. Lett., 10, 2575-2578 (2000).
Karthikeyan, K., Veenus, S. T., Lalitha, K. G., and Perumal,
P. T., Synthesis and antinociceptive activity of pyrazolyl
isoxazolines and pyrazolyl isoxazoles. Bioorg. Med. Chem.
Lett., 19, 3370-3373 (2009).
Okumura, H., Ashizawa, N., Aotsuka, T., Asakura, R.,