Synthesis and antioxidant activity of a new class of pyrazolyl indoles, thiazolyl pyrazolyl indoles

Article abstract of DOI:10.1007/s00044-017-1827-8

A new class of bis and tris heterocycles–pyrazolyl indoles and thiazolyl pyrazolyl indoles were prepared from the Michael acceptor (E)-3-(1H-indol-3-yl)-1-arylprop-2-en-1-ones by ultrasound irradiation technique and tested for antioxidant activity. The th

Full text of DOI:10.1007/s00044-017-1827-8

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-017-1827-8
ORIGINAL RESEARCH
Synthesis and antioxidant activity of a new class of pyrazolyl
indoles, thiazolyl pyrazolyl indoles
1 ●
1 ●
1 ●
Nagarjuna Ummadi Sravya Gundala Padmavathi Venkatapuram
1
Padmaja Adivireddy
Received: 1 August 2015 / Accepted: 28 February 2017
©
Springer Science+Business Media New York 2017
Abstract A
new
class
of
bis
and
tris
thiazoles. Indole and their derivatives possess anticancer
(Chen et al. 1996), antioxidant (Suzen and Buyukbingol
2000), antidepressant (Zhou et al. 2008), anticonvulsant
(Ahuja and Siddiqui 2014), antifungal (Zhang et al. 2013),
antiviral (Zhang et al. 2015), anti-inflammatory (Radwan
et al. 2007), anti-rheumatoidal (Buyukbingol et al. 1994)
and anti-HIV (Suzen and Buyukbingol 1998) activities.
Many indole derivatives are considered as the most potent
scavenger of free radicals (Chyan et al. 1999). In addition,
pyrazole is endowed with diverse pharmacological activ-
ities, such as antimicrobial (Sridhar et al. 2004), anti-
inflammatory (Raffa et al. 2010), anticancer (Altintop et al.
2014), antiviral (El-Sabbagh et al. 2009), anticonvulsant
and antidepressant (Abdel-Aziz et al. 2009). Several pyr-
azole drugs for example, celecoxib demonstrates anti-
inflammation effect and inhibits COX-2, rimonabant func-
tions as cannabinoid receptor and is utilized in obesity
treatment, fomepizole inhibits alcohol dehydrogenase and
sildenafil inhibits phosphodiesterase. Thiazoles have also
attracted a great deal of interest due to their presence in
natural products and pharmaceutical agents. Thiazole deri-
vatives exhibit antioxidant, antibacterial, antifungal, anti-
tubercular, diuretic, anti-inflammatory and anticancer
activities (Siddiqui et al. 2009). Riluzole, a novel neuro-
protective drug; sulfathiazole, an antimicrobial drug; bleo-
mycin, an antineoplastic drug; epothiloneA (Wu and Yang
heterocycles–pyrazolyl indoles and thiazolyl pyrazolyl
indoles were prepared from the Michael acceptor (E)-3-
(
1H-indol-3-yl)-1-arylprop-2-en-1-ones by ultrasound irra-
diation technique and tested for antioxidant activity. The
thiazolyl pyrazolyl indoles and pyrazolyl indoles showed
greater radical scavenging activity than pyrazolinyl indoles.
Amongst all the tested compounds, 3-(1-(4′′-
(
p-chlorophenyl)thiazol-2′′-yl)-3′-p-tolyl-1H-pyrazol-5′-yl)-
1
3
H-indole (7b) and 3-(1-(4′′-(p-chlorophenyl)thiazol-2′′-yl)-
′-(p-methoxyphenyl)-1H-pyrazol-5′-yl)-1H-indole (7c)
displayed promising antioxidant activity when compared
with standard drug ascorbic acid. The compounds having
electron donating groups (CH , OCH ) on the phenyl ring
exhibited greater antioxidant activity than those with elec-
tron withdrawing groups (Cl, Br, NO2).
3
3
●
●
●
Keywords Indole Pyrazole Thiazole
Cyclocondensation Antioxidant activity
●
Introduction
Nitrogen containing five-memberedand six-membered het-
erocyclic systems are scaffolds of many efficacious drugs.
One such class of compounds are indoles, pyrazoles and
2
011), an anticancer drug consist of thiazole containing
drugs. It is well known that the combination of two or more
types of heterocycles into one molecule could yield a novel
entity, with enhanced biological properties. Prompted by
the above observations and in continuation of our studies
towards the synthesis of a variety of bioactive heterocycles,
herein we describe the synthesis and antioxidant activity of
a new class of pyrazolyl indoles and thiazolyl pyrazolyl
indoles.
*
Padmaja Adivireddy
adivireddyp@yahoo.co.in
1
Department of Chemistry, Sri Venkateswara University, Tirupati
5
17502 Andhra Pradesh, India

Med Chem Res
Results and discussion
Chemistry
compounds 4, 5 and 7 and control drug are presented in
Tables 1–3, respectively. The mean antioxidant values are
shown visually in Figs. 1–3. Amongst all the tested com-
pounds, 3-(1-(4′′-(p-chlorophenyl)thiazol-2′′-yl)-3′-p-tolyl-
1H-pyrazol-5′-yl)-1H-indole (7b) and 3-(1-(4′′-(p-chlor-
ophenyl)thiazol-2′′-yl)-3′-(p-methoxyphenyl)-1H-pyrazol-5′-
yl)-1H-indole) (7c) displayed promising radical scavenging
activity in all the three methods when compared with the
standard drug, ascorbic acid. The 5′-(1H-indol-
3-yl)-3′-p-tolyl-1H-pyrazole-1′-carbothioamide (5b) and 5′-
(1H-indol-3-yl)-3′-(p-methoxyphenyl)-1H-pyrazole-1′-car-
bothioamide (5c) also showed good radical scavenging
activity. However, 4′,5′-dihydro-5′-(1H-indol-3-yl)-3′-p-
tolylpyrazole-1′-carbothioamide (4b) and 4′,5′-dihydro-5′-
(1H-indol-3-yl)-3′-(p-methoxyphenyl)pyrazole-1′-carbothioa-
mide (4c) displayed least activity, while 3′-(p-chlorophenyl)-
4′,5′-dihydro-5′-(1H-indol-3-yl)pyrazole-1′-carbothioamide
(4d), 3′-(p-bromophenyl)-4′,5′-dihydro-5′-(1H-indol-3-yl)
pyrazole-1′-carbothioamide (4e) and 4′,5′-dihydro-5′-
(1H-indol-3-yl)-3′-(p-nitrophenyl)pyrazole-1′-carbothioamide
(4f) showed no activity. The structure–activity relationship
of the compounds revealed that the compounds having
indole in combination with pyrazole and thiazole moieties
showed greater radical scavenging activity. Moreover,
compounds with indole and pyrazole moieties displayed
higher antioxidant activity than those with indole and pyr-
azoline. It was observed that electron donating groups
(CH , OCH ) on the phenyl ring enhanced the activity when
The 4′,5′-dihydro-5′-(1H-indol-3-yl)-3′-arylpyrazole-1′-car-
bothioamide (4), 5′-(1H-indol-3-yl)-3′-aryl-1H-pyrazole-1′-
carbothioamide (5) and 3-(1-(4′′-(p-chlorophenyl)thiazol-2′
′
-yl)-3′-aryl-1H-pyrazol-5′-yl)-1H-indole (7) were synthe-
sized from the Michael acceptor (E)-3-(1H-indol-3-yl)-1-
arylprop-2-en-1-one (3) (Scheme 1). In fact, the compound
3
was prepared by the Claisen–Schmidt reaction of indole-
3
-carboxaldehyde (1) and aryl ketones (2) in the presence of
1
NaOH in methanol by ultrasound irradiation. The H NMR
spectrum of 3a displayed two doublets at δ 8.06 and 7.66
ppm due to olefin protons, H and H . The coupling con-
stant value JAB = 16.2 Hz indicated their trans geometry.
Adopting similar methodology, the reaction of compound 3
with thiosemicarbazide in the presence of NaOH in ethanol
led to the formation of 4. The H NMR spectrum of 4a
exhibited an AMX splitting pattern for pyrazoline ring
protons. The three doublets of doublets appeared at δ 4.87,
A
B
1
3
.75, 3.02 ppm were assigned to H , HM and H , respec-
A X
tively. The coupling constant values JAM = 12.5, JMX = 10.8
and JAX = 6.7 Hz indicated that H , H are cis, H , Hx are
A
M
A
trans and H , HX are geminal. In addition, two broad
M
singlets were observed at δ 10.01, 5.53 ppm due to NH and
NH , respectively, which disappeared on deuteration. Oxi-
2
dation of 4 with chloranil in xylene furnished the aroma-
3
3
1
tized product 5. The H NMR spectrum of 5a showed a
compared with electron withdrawing groups (Cl, Br, NO2).
Furthermore, the free radical scavenging activity of the
compounds 7b and 7c was measured at different con-
centrations, and monitored the change in absorbance at 10,
20 and 30 min in DPPH method (Table 4). It was perceived
that at these 10 min intervals, the values are very close and
the results exemplified that the antioxidant activity is
independent of time.
singlet at δ 6.72, and two broad singlets at 10.06 and 5.56
ppm due to C ′–H, NH and NH , respectively. The signals
4
2
due to highly acidic protons disappeared when D O was
2
added. Furthermore, compound 7 was obtained by
exploiting thioamide group in 5. Thus the cyclocondensa-
tion reaction of 5 with p-chlorophenacyl bromide (6) under
ultrasonication provided 3-(1-(4′′-(p-chlorophenyl)thiazol-
1
2
′′-yl)-3′-aryl-1H-pyrazol-5′-yl)-1H-indole (7). The
H
NMR spectrum of 7a displayed a singlet at δ 6.75 due to
C –H. Another singlet corresponding to C –H was
Statistical analysis
4
′
5′′
observed at downfield region and merged with aromatic
protons. The structures of all the compounds were further
established by infrared spectroscopy (IR), carbon-13
nuclear magnetic resonance ( C NMR), mass spectra and
elemental analyses.
All experiments are performed in triplicate (n = 3), and an
analysis of variance (ANOVA) test (Microsoft Excel) is
used to compare the mean values across compounds and
concentrations. The results represented means ± standard
deviation (SD) of three replicated determinations. The
descriptive analysis is supported by the statistical analysis.
The following inferences are supported through ANOVA
analysis (Tables 5, 6, and 7). Since the p-value of rows
(compounds) is less than 0.05 (α) can’t reject the null
hypothesis, and so conclude (with 95% confidence) that
there is significant difference in radical scavenging activity
exhibited by the compounds for different concentrations.
Since the p-value of columns (concentrations) less than 0.05
(α) can’t reject the null hypothesis, and so conclude (with
1
3
Biological evaluation
Antioxidant activity
The compounds 4, 5 and 7 were tested for antioxidant
activity by 2,2-diphenylpicrylhydrazyl (DPPH), nitric oxide
(
NO) and hydrogen peroxide (H O ) methods. The
2 2
experimental data on the antioxidant activity of the

Med Chem Res
H
A
O
O
CHO
CH3
i
+
H
B
N
N
R
H
R
H
1
2
3
R
R
5
"
HM
HX
6"
1"
4"
3
"
2
"
HA
4
' 3'
5
'
N
N
iii
ii
5
8
N
6
7
N
4
9
3
1 2
3
N
H
z
N
S
NH2
S
NH2
H
5
4
R
O
Br
N
S
iv
5
+
N
Cl
N
2'''
N 4
H
''' 5'''
6
1
2
6
5
3
4
Cl
7
i) MeOH / NaOH / ))))
ii) NH CSNHNH / NaOH / EtOH / ))))
iii) Chloranil / Xylene / ))))
iv) EtOH / ))))
R = a) H
d) Cl
e) Br
b) Me
c) OMe
2
2
f) NO2
Scheme 1 Synthesis of pyrazolyl indoles and thiazolyl pyrazolyl indoles
9
5% confidence) that there is significant difference in
that there are significant differences in the interaction
radical scavenging activity displayed across the compounds.
between compounds and concentrations.
Besides, the p-value (interactions) less than 0.05 indicates

Med Chem Res
IC50
Table 1 The in vitro
antioxidant activity of 4, 5 and 7
in DPPH method
−1
Compound
Concentration (µg ml )
50
75
100
Mean ± SD
Mean ± SD
Mean ± SD
Mean ± SD
4
4
4
4
4
4
5
5
5
5
5
5
7
7
7
7
7
7
a
b
c
d
e
f
22.49 ± 0.14
24.32 ± 0.26
27.41 ± 0.19
–
23.73 ± 0.19
26.56 ± 0.32
29.84 ± 0.12
–
25.92 ± 0.16
28.76 ± 0.28
31.63 ± 0.34
–
192.90 ± 0.012
173.85 ± 0.016
158.00 ± 0.031
–
–
–
–
–
–
–
–
–
a
b
c
d
e
f
37.43 ± 0.35
40.45 ± 0.29
44.73 ± 0.11
35.49 ± 0.09
36.36 ± 0.16
32.54 ± 0.11
65.23 ± 0.06
75.15 ± 0.24
76.72 ± 0.08
57.93 ± 0.13
61.68 ± 0.09
51.29 ± 0.13
74.24 ± 0.10
–
39.67 ± 0.40
42.72 ± 0.22
46.53 ± 0.19
36.88 ± 0.11
38.21 ± 0.25
34.19 ± 0.34
66.10 ± 0.64
77.68 ± 0.14
78.88 ± 0.24
58.42 ± 0.14
62.96 ± 0.46
53.81 ± 0.66
76.43 ± 0.13
–
41.83 ± 0.88
43.54 ± 0.25
48.28 ± 0.18
39.36 ± 0.60
40.43 ± 0.32
36.54 ± 0.29
68.39 ± 0.31
79.65 ± 0.33
80.79 ± 0.41
60.50 ± 0.75
64.37 ± 0.66
55.11 ± 0.34
78.52 ± 0.35
–
119.53 ± 0.019
114.83 ± 0.011
103.56 ± 0.025
127.00 ± 0.046
123.67 ± 0.031
136.83 ± 0.028
38.32 ± 0.045
33.26 ± 0.065
32.58 ± 0.058
43.15 ± 0.014
40.53 ± 0.048
48.74 ± 0.032
33.67 ± 0.019
–
a
b
c
d
e
f
Ascorbic acid
Blank
–
, no activity
Conclusion
determined in open capillaries on a Mel-Temp apparatus and
are uncorrected. The homogeneity of the compounds was
checked by thin-layer chromatography (TLC) (silica gel H,
BDH, hexane/ethyl acetate, 3:1). The IR spectra were
recorded on a Thermo Nicolet IR 200 FT-IR spectrometer as
A new class of bis and tris heterocycles–pyrazolyl indoles
and thiazolyl pyrazolyl indoles were prepared from the
Michael acceptor (E)-3-(1H-indol-3-yl)-1-arylprop-2-en-1-
one by ultrasound irradiation technique, and tested for
antioxidant activity. The thiazolyl pyrazolyl indoles deri-
vatives and indolyl pyrazoles showed higher radical
scavenging activity. Among all the tested compounds, 3-(1-
−1
KBr pellets and the wave numbers are given in cm . The
1
H NMR spectra were recorded in DMSO-d on a Jeol JNM
6
1
3
λ-400 MHz spectrometer. The C NMR spectra were
recorded in DMSO-d on a Jeol JNM spectrometer operating
6
(
4′′-(p-chlorophenyl)thiazol-2′′-yl)-3′-p-tolyl-1H-pyrazol-5′-
yl)-1H-indole (7b) and 3-(1-(4′′-(p-chlorophenyl)thiazol-2′
-yl)-3′-(p-methoxyphenyl)-1H-pyrazol-5′-yl)-1H-indole
7c) displayed promising antioxidant activity when com-
at λ-100 MHz. High-resolution mass spectra were recorded
on Micromass Q-TOF micromass spectrometer using elec-
trospray ionization. All chemical shifts are reported in
δ (ppm) using Tetramethylsilane as an internal standard. The
microanalyses were performed on a Perkin–Elmer 240 C
elemental analyzer. The temperature was measured by
flexible probe throughout the reaction. The starting com-
pound (E)-3-(1H-indol-3-yl)-1-arylprop-2-en-1-one (3) was
prepared as per the literature procedure (Faritha et al. 2014).
′
(
pared with the standard drug, ascorbic acid. It was also
noticed that the electron donating groups (CH , OCH ) on
the phenyl ring exhibited higher radical scavenging activity
than those with electron withdrawing groups (Cl, Br, NO2).
3
3
Experimental protocols
General procedure for the synthesis of 4′,5′-dihydro-5′-
(
1H-indol-3-yl)-3′-arylpyrazole-1′-carbothio amide (4a–f)
All the chemicals were purchased from commercial sources
and used without further purification. Ultrasonication was
performed in a Bandelin Sonorex RK 102H ultrasonic bath
operating at frequency of 35 kHz. Melting points were
To an equimolar (1 mmol) mixture of compound 3 and
thiosemicarbazide, ethanol (3 ml) and sodium hydroxide
(1.5 mmol) were added. It was sonicated for 1–2 h at room

Med Chem Res
Table 2 The in vitro antioxidant activity of 4, 5 and 7 in H
O
2 2
Table 3 The in vitro antioxidant activity of 4, 5 and 7 in NO method
method
−
1
Compound
Concentration (µg ml
)
−1
Compound
Concentration (µg ml
)
5
0
75
100
5
0
75
100
Mean ± SD
Mean ± SD
Mean ± SD
Mean ± SD
Mean ± SD
Mean ± SD
4
4
4
4
4
4
5
5
5
5
5
5
7
7
7
7
7
7
a
b
c
d
e
f
27.43 ± 0.68
30.81 ± 0.32
33.27 ± 0.65
–
29.25 ± 0.39
32.32 ± 0.30
35.14 ± 0.95
–
31.74 ± 0.11
3451 ± 0.29
37.04 ± 0.34
–
4
4
4
4
4
4
5
5
5
5
5
5
7
7
7
7
7
7
a
b
c
d
e
f
25.64 ± 0.24
28.53 ± 0.85
31.45 ± 0.32
–
27.59 ± 0.09
30.63 ± 0.15
33.72 ± 0.34
–
29.53 ± 0.32
32.64 ± 0.28
35.43 ± 0.68
–
–
–
–
–
–
–
–
–
–
–
–
–
a
b
c
d
e
f
41.10 ± 0.41
46.35 ± 0.33
49.51 ± 0.06
36.19 ± 0.31
40.57 ± 0.42
34.74 ± 0.18
69.42 ± 0.37
79.07 ± 0.19
81.84 ± 0.65
61.29 ± 0.19
63.74 ± 0.31
53.16 ± 0.34
78.54 ± 0.66
–
43.82 ± 0.88
48.32 ± 0.46
51.48 ± 0.61
38.96 ± 0.18
42.32 ± 0.11
35.06 ± 0.32
70.71 ± 0.35
80.66 ± 0.18
82.25 ± 0.31
62.01 ± 0.10
64.26 ± 0.34
55.77 ± 0.29
80.22 ± 0.09
–
45.75 ± 0.58
50.55 ± 0.42
53.42 ± 0.33
39.37 ± 0.19
44.09 ± 0.91
37.54 ± 0.34
72.01 ± 0.10
83.35 ± 0.13
84.79 ± 0.43
65.04 ± 0.28
66.53 ± 0.28
57.62 ± 0.37
82.57 ± 0.18
–
a
b
c
d
e
f
39.29 ± 0.73
44.13 ± 0.69
47.42 ± 0.22
34.24 ± 0.17
38.82 ± 0.18
32.33 ± 0.28
67.12 ± 0.47
77.56 ± 0.48
79.73 ± 0.36
59.41 ± 0.29
61.37 ± 0.22
52.10 ± 0.39
76.48 ± 0.31
–
41.61 ± 0.28
46.79 ± 0.57
49.33 ± 0.37
36.46 ± 0.35
40.12 ± 0.28
33.24 ± 0.37
69.51 ± 0.34
78.78 ± 0.09
80.27 ± 0.33
61.39 ± 0.48
63.77 ± 0.18
54.59 ± 0.16
78.38 ± 0.0.43
–
43.13 ± 0.39
48.49 ± 0.29
51.71 ± 0.65
37.87 ± 0.18
42.63 ± 0.34
35.18 ± 0.16
71.56 ± 0.36
81.89 ± 0.14
82.47 ± 0.44
63.32 ± 0.32
65.92 ± 0.15
56.34 ± 0.34
80.24 ± 0.96
–
a
b
c
d
e
f
a
b
c
d
e
f
Ascorbic acid
Blank
Ascorbic acid
Blank
–
, no activity
–
, no activity
temperature. After completion of the reaction (monitored by
TLC), the contents of the flask were poured onto crushed
ice. The separated solid was collected by filtration and
purified by recrystallization from 2-propanol.
4′,5′-Dihydro-5′-(1H-indol-3-yl)-3′-p-tolylpyrazole-1′-
carbothioamide (4b)
o
−1
m. p. 133–135 C; yield 74%; IR (KBr) (cm ): 3445, 3337
1
(
(
NH ), 3233 (NH), 1576 (C=N), 1336 (C=S); H NMR
2
400 MHz, DMSO-d ) : δ 2.36 (s, 3H, Ar–CH ), 3.09 (dd,
6
3
4
′,5′-Dihydro-5′-(1H-indol-3-yl)-3′-phenylpyrazole-1′-
1H, H , J
6.6 Hz, JMX = 10.7 Hz), 3.79 (dd, 1H, HM,
AX =
X
carbothioamide (4a)
JAM = 12.7 Hz, JMX = 10.7 Hz), 4.91 (dd, 1H, H , J
A AM
1
2.7 Hz, JAX = 6.6 Hz), 5.71 (bs, 2H, NH ), 6.91–7.58 (m,
=
2
m. p. 150–152 C; yield 78%; IR (KBr) (cm−1): 3437, 3329
o
9 H, Ar–H & C –H), 10.12 (bs, 1H, NH); C NMR (100
MHz, DMSO-d ): δ 25.5 (Ar–CH ), 46.2 (C-4′), 67.8 (C-
13
2
1
(
(
NH ), 3237 (NH), 1571 (C=N), 1332 (C=S); H NMR
400 MHz, DMSO-d ): δ 3.02 (dd, 1H, H , J
JMX = 10.8 Hz), 3.75 (dd, 1H, H , J
0.8 Hz), 4.87 (dd, 1H, H , J
.53 (bs, 2H, NH ), 6.88–7.53 (m, 10H, Ar–H & C –H),
0.08 (bs, 1H, NH); C NMR (100 MHz, DMSO-d ): δ
5.1 (C-4′), 66.8 (C-5′), 112.3 (C-8), 118.7 (C-3), 120.4 (C-
), 124.6 (C-7), 126.2 (C-6), 127.6 (C-2), 128.4 (C-4),
30.1 (C-3′′ and C-5′′), 132.7 (C-2′′ and C-6′′), 133.5 (C-4′
2
6
3
6.7 Hz,
5′), 112.8 (C-8), 119.2 (C-3), 120.8 (C-5), 125.1 (C-7),
126.8 (C-6), 128.2 (C-2), 128.9 (C-4), 130.6(C-3′′&C-5′′),
133.5(C-2′′&C-6′′), 135.6 (C-1′′), 136.4 (C-9), 141.2 (C-4′
′), 158.1 (C-3′), 177.2 (C=S); MS (m/z): 357.1136 [M +
Na]. Anal. calcd. for C H N S: C, 68.23; H, 5.42; N,
6
X
AX =
12.5 Hz, JMX
M
AM =
1
12.5 Hz, JAX = 6.7 Hz),
AM =
=
A
5
1
4
5
1
2 2
1
3
6
19 18 4
16.75%; found: C, 68.18; H, 5.43; N, 16.85%.
4′,5′-Dihydro-5′-(1H-indol-3-yl)-3′-(p-methoxyphenyl)
pyrazole-1′-carbothioamide (4c)
′
), 134.8 (C-1′′), 135.3 (C-9), 157.2 (C-3′), 176.0 (C=S);
MS (m/z): 343.0982 [M + Na]. Anal. calcd. for C H N S:
1
8 16 4
o
−1
C, 67.47; H, 5.03; N, 17.49%; found: C, 67.55; H, 5.01; N,
7.63%.
m. p. 147–148 C; yield 76%; IR (KBr) (cm ): 3430, 3326
1
1
(NH ), 3235 (NH), 1568 (C=N), 1329 (C=S); H NMR
2

Med Chem Res
Fig. 1 The in vitro antioxidant
activity of 4, 5 and 7 in DPPH
method
Fig. 2 The in vitro antioxidant
activity of 4, 5 and 7 in H O
2 2
method
Fig. 3 The in vitro antioxidant
activity of 4, 5 and 7 in NO
method
(
400 MHz, DMSO-d ): δ 3.04 (dd, 1H, H , J
6.2 Hz,
Table 4 Antioxidant activity of 7b and 7c at 10 min. time intervals by
6
X
AX =
JMX = 10.4 Hz), 3.72 (dd, 1H, H , J
12.4 Hz, JMX
DPPH scavenging method
M
AM =
1
1
0.4 Hz), 3.81 (s, 3H, Ar–OCH ), 4.80 (dd, 1H, H , J
3 A AM
=
=
Compound
10 min
20 min
30 min
2.4 Hz, JAX = 6.2 Hz), 5.41 (bs, 2H, NH ), 6.86–7.52 (m,
2
1
3
7b
79.42
80.56
79.60
80.69
79.92
80.84
9
H, Ar–H & C –H), 9.15 (bs, 1H, NH); C NMR (100
2
MHz, DMSO-d ): δ 44.9 (C-4′), 56.8 (Ar–OCH ), 66.2 (C-
7
c
6
3
5
(
1
′), 111.9 (C-8), 118.4(C-3′′ and C-5′′), 120.1 (C-3), 124.2
C-5), 125.8 (C-7), 127.3 (C-6), 128.1 (C-2), 132.5 (C-1′′),
34.5 (C-4), 138.0 (C-2′′ and C-6′′), 135.1 (C-9), 155.2

Med Chem Res
Table 5 ANOVA analysis of 4, 5 and 7 in DPPH method
Source of variation
SS (total sum
of squares)
df (degrees
of freedom)
MS (mean
square)
F (F statistic)
P-value
F Critical
(F statistic
critical)
Rows(compounds)
Columns(concentrations)
Interaction
46419.20
334.29
16.32
15
2
3094.60
167.15
0.54
19104.925
1031.894
3.358
0.000
0.000
0.000
1.772
3.091
1.578
30
96
143
Within
15.55
0.16
Total
46785.35
Table 6 ANOVA analysis of 4, 5 and 7 in H2O2 method
Source of variation
SS (total sum
of squares)
df (degrees
of freedom)
MS (mean
square)
F (F statistic)
P-value
F Critical
(F statistic
critical)
Rows(compounds)
Columns(concentrations)
Interaction
45804.06
369.56
15
2
3053.60
184.78
0.45
16805.553
1016.948
2.500
0.000
0.000
0.000
1.772
3.091
1.578
13.63
30
96
143
Within
17.44
0.18
Total
46204.691
Table 7 ANOVA analysis of 4, 5 and 7 in NO method
Source of variation
SS (total sum
of squares)
df (degrees
of freedom)
MS (mean
square)
F (F statistic)
P-value
F Critical
(F statistic
critical)
Rows(compounds)
Columns(concentrations)
Interaction
44727.58
369.15
53.50
15
2
2981.84
184.58
1.78
2893.941
179.136
1.731
0.000
0.000
0.024
1.772
3.091
1.578
30
96
143
Within
98.92
1.03
Total
45249.15
(
+
C-4′′), 156.8 (C-3′), 175.6 (C=S); MS (m/z): 373.1084 [M
C, 60.92; H, 4.26; N, 15.79%; found: C, 60.99; H, 4.28; N,
15.95%.
Na]. Anal. calcd. for C H N OS: C, 65.12; H, 5.18; N,
19 18 4
1
5.99%; found: C, 65.21; H, 5.17; N, 16.18%.
3
′-(p-Bromophenyl)-4′,5′-dihydro-5′-(1H-indol-3-yl)
pyrazole-1′-carbothioamide (4e)
3
′-(p-Chlorophenyl)-4′,5′-dihydro-5′-(1H-indol-3-yl)
o
−1
pyrazole-1′-carbothioamide (4d)
m. p. 162–164 C; yield 77%; IR (KBr) (cm ): 3436, 3332
1
(
NH ), 3230 (NH), 1577 (C=N), 1333 (C=S); H NMR
(400 MHz, DMSO-d ): δ 3.07 (dd, 1H, H , J
JMX = 10.6 Hz), 3.76 (dd, 1H, H , J
10.6 Hz), 4.89 (dd, 1H, H , J
2
o
−1
m. p. 156–158 C; yield 80%; IR (KBr) (cm ): 3452, 3342
6.5 Hz,
AX =
6
X
1
(
(
NH ), 3236 (NH), 1580 (C=N), 1338 (C=S); H NMR
400 MHz, DMSO-d ): δ 3.11 (dd, 1H, H , J
12.6 Hz, JMX
AM =
12.6 Hz, JAX = 6.5 Hz),
AM =
2
M
6.4 Hz,
6
X
AX =
=
A
JMX = 10.8 Hz), 3.82 (dd, 1H, H , J
12.8 Hz, JMX
5.62 (bs, 2H, NH ), 6.89–7.55 (m, 9H, Ar–H & C –H),
2 2
M
AM =
1
3
1
0.8 Hz), 4.94 (dd, 1H, H , J
12.8 Hz, JAX = 6.4 Hz),
10.19 (bs, 1H, NH); C NMR (100 MHz, DMSO-d ): δ
=
A
AM =
6
5
1
4
5
1
1
.79 (bs, 2H, NH ), 6.93–7.64 (m, 9H, Ar–H & C –H),
45.8 (C-4′), 67.2 (C-5′), 112.5 (C-8), 118.9 (C-3), 120.6 (C-
5), 124.8 (C-7), 126.5 (C-6), 127.9 (C-2), 128.7 (C-4′′),
130.4 (C-4), 132.9 (C-2′′&C-6′′), 133.8 (C-3′′&C-5′′), 135.3
(C-1′′), 135.8 (C-9), 157.6 (C-3′), 176.4 (C=S); MS (m/z):
422.2953 [M + Na]. Anal. calcd. for C H BrN S: C,
2
2
1
3
0.17 (bs, 1H, NH); C NMR (100 MHz, DMSO-d ): δ
6
6.5 (C-4′), 68.1 (C-5′), 112.9 (C-8), 120.1 (C-3), 121.3 (C-
), 125.6 (C-7), 127.2 (C-6), 128.4 (C-2), 129.3 (C-4),
30.8 (C-3′′&C-5′′), 133.8 (C-2′′&C-6′′), 135.7 (C-1′′),
36.6 (C-9), 137.4 (C-4′′), 158.4 (C-3′), 177.8 (C=S); MS
1
8
15
4
54.14; H, 3.79; N, 14.03%; found: C, 54.24; H, 3.80; N,
(
m/z): 377.0592 [M + Na]. Anal. calcd. for C H ClN S:
18 15 4
14.21%.

Med Chem Res
4
′,5′-Dihydro-5′-(1H-indol-3-yl)-3′-(p-nitrophenyl)
(100 MHz, DMSO-d ): δ 24.7 (Ar-CH ), 100.7 (C-4′),
6
3
pyrazole-1′-carbothioamide (4f)
113.1 (C-8), 119.7 (C-5), 121.2 (C-7), 125.8 (C-6), 127.4
C-2′′&C-6′′), 128.6 (C-3), 129.5 (C-2), 131.2 (C-3′′&C-5′
(
o
−1
m. p. 171–173 C; yield 82%; IR (KBr) (cm ): 3459, 3348
′), 135.3 (C-1′′), 136.2 (C-4), 136.8 (C-9), 141.7 (C-4′′),
145.3 (C-5′), 158.5 (C-3′), 177.6 (C=S); MS (m/z):
355.0981 [M + Na]. Anal. calcd. for C H N S: C, 68.65;
1
(
(
NH ), 3242 (NH), 1581 (C=N), 1341 (C=S); H NMR
2
400 MHz, DMSO-d ): δ 3.14 (dd, 1H, H , J
6.8 Hz,
6
X
AX =
19 16 4
JMX = 10.9 Hz), 3.85 (dd, 1H, H , J
12.9 Hz, JMX
H, 4.85; N, 16.85%; found: C, 68.76; H, 4.87; N, 17.15%.
M
AM =
1
0.9 Hz), 4.98 (dd, 1H, H , J
12.9 Hz, JAX = 6.8 Hz),
AM =
=
A
5
1
4
5
.84 (bs, 2H, NH ), 6.95–7.67 (m, 9H, Ar–H & C2–H),
5′-(1H-Indol-3-yl)-3′-(p-methoxyphenyl)-1H-pyrazole-1′-
carbothioamide (5c)
2
1
3
0.20 (bs, 1H, NH); C NMR (100 MHz, DMSO-d ): δ
6
6.8 (C-4′), 68.4 (C-5′), 113.1 (C-8), 120.3 (C-3), 121.5 (C-
), 125.8 (C-7), 127.6 (C-3′′&C-5′′), 128.6 (C-6), 129.5
m. p. 151–153 C; yield 71%; IR (KBr) (cm−1): 3437, 3330
o
(
(
C-2), 131.2 (C-4), 134.2 (C-2′′&C-6′′), 138.7 (C-9), 140.2
C-1′′), 141.3 (C-4′′), 158.9 (C-3′), 178.2 (C=S); MS (m/z):
(NH ), 3248 (NH), 1626 (C=C), 1573 (C=N), 1336
2
1
(C=S); H NMR (400 MHz, DMSO-d ): δ 3.87 (s, 3H,
6
3
5
1
88.0839 [M + Na]. Anal. calcd. for C H N O S: C,
9.16; H, 4.14; N, 19.17%; found: C, 59.28; H, 4.18; N,
9.40%.
Ar-OCH ), 5.49 (bs, 2H, NH ), 6.65 (s, 1H, C ′-H),
1
8
15
5
2
3
2
4
1
3
6.88–7.54 (m, 9H, Ar–H & C2–H), 10.20 (bs, 1H, NH);
C
NMR (100 MHz, DMSO-d ): δ 57.1 (Ar-OCH ), 99.1 (C-
6
3
4
′), 112.2 (C-8), 118.9 (C-2′′&C-6′′), 120.8 (C-5), 124.6 (C-
General procedure for the synthesis of 5′-(1H-indol-3-
yl)-3′-aryl-1H-pyrazole-1′-carbothioamide (5a–f)
7), 126.2 (C-6), 127.9 (C-3), 128.5 (C-1′′), 130.5 (C-2),
133.6 (C-3′′&C-5′′), 138.8 (C-4), 139.4 (C-9), 144.5 (C-5′),
155.4 (C-4′′), 157.1 (C-3′), 175.8 (C=S); MS (m/z):
A solution of compound 4 (1 mmol) and chloranil (1.2
371.0930 [M + Na]. Anal. calcd. for C H N OS: C,
1
9 16 4
mmol) in xylene (10 ml) was subjected to ultrasound irra-
diation for 4–5 h at 60 C. Then it was treated with 5%
65.50; H, 4.63; N, 16.08%; found: C, 65.58; H, 4.64; N,
16.22%.
o
NaOH solution. The organic layer was separated and
repeatedly washed with water. It was dried over an. Na SO
and the solvent was removed under reduced pressure. The
resultant solid was recrystallized from 2-propanol.
3′-(p-Chlorophenyl)-5′-(1H-indol-3-yl)-1H-pyrazole-1′-
carbothioamide (5d)
2
4
m. p. 160–162 C; yield 76%; IR (KBr) (cm−1): 3458, 3347
o
5
′-(1H-Indol-3-yl)-3′-phenyl-1H-pyrazole-1′-
(NH ), 3253 (NH), 1634 (C=C), 1588 (C=N), 1344
2
1
carbothioamide (5a)
(C=S); H NMR (400 MHz, DMSO-d ): δ 5.81 (bs, 2H,
6
NH ), 6.86 (s, 1H, C ′-H), 6.96–7.67 (m, 9H, Ar–H &
2
4
m. p. 143–145 C; yield 75%; IR (KBr) (cm−1): 3441, 3333
o
C2–H), 10.22 (bs, 1H, NH); C NMR (100 MHz, DMSO-
d6): δ 101.4 (C-4′), 113.5 (C-8), 120.7 (C-5), 122.0 (C-7),
125.9 (C-6), 127.8 (C-3), 128.7 (C-2), 129.9 (C-2′′&C-6′′),
131.6 (C-3′′&C-5′′), 134.2 (C-1′′), 136.3 (C-4), 137.6 (C-9),
138.7 (C-4′′), 145.7 (C-5′), 158.7 (C-3′), 178.2 (C=S); MS
(m/z): 375.0432 [M + Na]. Anal. calcd. for C H ClN S:
13
(
(
NH ), 3245 (NH), 1628 (C=C), 1575 (C=N), 1337
C=S); H NMR (400 MHz, DMSO-d ): δ 5.56 (bs, 2H,
NH ), 6.72 (s, 1H, C ′-H), 6.90–7.55 (m, 9H, Ar–H &
C2–H), 10.16 (bs, 1H, NH); C NMR (100 MHz, DMSO-
d6): δ 99.6 (C-4′), 112.6 (C-8), 119.2 (C-5), 120.9 (C-7),
2
1
6
2
4
1
3
18
13
4
125.2 (C-6), 126.8 (C-2′′&C-6′′), 127.7 (C-3), 128.1 (C-2),
130.5 (C-4′′), 133.4 (C-3′′&C-5′′), 134.2 (C-1′′), 135.5 (C-
4), 136.2 (C-9), 144.8 (C-5′), 157.7 (C-3′), 176.2 (C=S);
C, 61.27; H, 3.71; N, 15.88%; found: C, 61.40; H, 3.73; N,
16.12%.
MS (m/z): 341.0826 [M + Na]. Anal. calcd. for C H N S:
C, 67.90; H, 4.43; N, 17.60%; found: C, 68.00; H, 4.46; N,
3′-(p-Bromophenyl)-5′-(1H-indol-3-yl)-1H-pyrazole-1′-
carbothioamide (5e)
1
8 14 4
1
7.79%.
o
−1
m. p. 155–157 C; yield 79%; IR (KBr) (cm ): 3446, 3339
1
5
′-(1H-Indol-3-yl)-3′-p-tolyl-1H-pyrazole-1′-
(NH ), 3247 (NH), 1630 (C=C), 1578 (C=N), 1340; H
2
carbothioamide (5b)
NMR (400 MHz, DMSO-d ): δ 5.65 (bs, 2H, NH ), 6.77 (s,
6
2
1
H, C ′-H), 6.93–7.59 (m, 9H, Ar–H & C2–H), 10.25 (bs,
4
m. p. 128–130 C; yield 73%; IR (KBr) (cm−1): 3454, 3343
o
1H, NH); C NMR (100 MHz, DMSO-d ): δ 100.2 (C-4′),
13
6
(
(
NH ), 3251 (NH), 1631 (C=C), 1582 (C=N), 1343
145.0 (C-5′), 112.9 (C-8), 119.3 (C-5), 121.3 (C-7), 125.4
(C-6), 127.1 (C-4′′), 128.3 (C-3), 129.2 (C-2), 130.8 (C-2′′
&C-6′′), 133.2 (C-4), 134.7 (C-1′′), 136.8 (C-3′′&C-5′′),
137.2 (C-9), 157.9 (C-3′), 176.8 (C=S); MS (m/z):
2
1
C=S); H NMR (400 MHz, DMSO-d ): δ 2.37 (s, 3H, Ar-
6
CH ), 5.73 (bs, 2H, NH ), 6.83 (s, 1H, C ′-H), 6.94–7.62
(
3
2
4
1
3
m, 9H, Ar–H & C2–H), 10.18 (bs, 1H, NH); C NMR

Med Chem Res
4
5
1
20.2823 [M + Na]. Anal. calcd. for C H BrN S: C,
4.42; H, 3.30; N, 14.10%; found: C, 55.52; H, 3.29; N,
4.28%.
d ): δ 2.39 (s, 3H, Ar-CH ), 6.84 (s, 1H, C ′-H), 6.97–7.64
6 3 4
1
8
13
4
1
3
(m, 14H, Ar–H, C2–H, C -H), 10.79 (bs, 1H, NH);
C
5
′′
NMR (100 MHz, DMSO-d ): δ 24.9 (Ar-CH ), 100.8 (C-
6
3
4
′), 68.3 (C-5′), 113.8 (C-8), 120.1 (C-5), 123.2 (C-7),
5
′-(1H-Indol-3-yl)-3′-(p-nitrophenyl)-1H-pyrazole-1′-
126.9 (C-6), 127.8 (C-2′′&C-6′′), 128.6 (C-2), 129.7 (C-
v
v
v
v
carbothioamide (5f)
2′ &C-6′ ), 129.9 (C-3′ &C-5′ ), 130.2 (C-3′′&C-5′′), 131.8
v
v
(
C-1′′), 132.4 (C-1′ ), 133.8 (C-4), 134.0 (C-4′ ), 135.6 (C-
m. p. 166–168 C; yield 83%; IR (KBr) (cm−1): 3464, 3350
o
3), 136.2 (C-9), 137.8 (C-4′′), 145.6 (C-5′′), 155.1 (C-4′′′),
158.8 (C-3′), 161.5 (C-2′′); MS (m/z): 489.0907 [M + Na].
Anal. calcd. for C H ClN S: C, 69.44; H, 4.10; N,
(
(
NH ), 3256 (NH), 1637 (C=C), 1586 (C=N), 1347
C=S); H NMR (400 MHz, DMSO-d ): δ 5.86 (bs, 2H,
2
1
6
27 19
4
NH ), 6.90 (s, 1H, C ′-H), 6.98–7.71 (m, 9H, Ar–H &
C2–H), 10.28 (bs, 1H, NH), C NMR (100 MHz, DMSO-
d6): δ 101.7 (C-4′), 114.3 (C-8), 121.2 (C-5), 122.4 (C-7),
12.00%; found: C, 69.55; H, 4.12; N, 12.22%.
2
4
1
3
3-(1-(4′′-(p-Chlorophenyl)thiazol-2′′-yl)-3′-(p-
methoxyphenyl)-1H-pyrazol-5′-yl)-1H-indole (7c)
125.9 (C-6), 128.1 (C-3′′&C-5′′), 129.6 (C-3), 130.2 (C-2),
131.7 (C-2′′&C-6′′), 135.1 (C-4), 136.8 (C-9), 137.2 (C-1′′),
141.6 (C-4′′), 146.2 (C-5′), 159.2 (C-3′), 178.6 (C=S); MS
m. p. 190–192 C; yield 75%; IR (KBr) (cm−1): 3248 (NH),
o
1
(
m/z): 386.0673 [M + Na]. Anal. calcd. for C H N O S:
1628 (C=C), 1579 (C=N); H NMR (400 MHz, DMSO-
1
8 13 5 2
C, 59.49; H, 3.61; N, 19.27%; found: C, 59.61; H, 3.63; N,
9.47%.
d ): δ 3.89 (s, 3H, Ar-OCH ), 6.68 (s, 1H, C -H), 6.90–7.60
6
3
4′
1
3
1
(m, 14H, Ar–H, C2–H, C -H), 9.98 (bs, 1H, NH);
C
5
′′
NMR (100 MHz, DMSO-d ): δ 57.6 (Ar-O-CH ), 99.6
6
3
General procedure for the synthesis of 3-(1-(4′′-(p-
chlorophenyl)thiazol-2′′-yl)-3′-aryl-1H-pyrazol-5′-yl)-
(C-4′), 112.1 (C-5′′), 111.6 (C-8), 119.2 (C-5), 121.9
(C-7), 126.1 (C-6), 126.9 (C-1′′), 127.1 (C-2), 128.2
v
v
v
v
1
H-indole (7a–f)
(C-2′′&C-6′′), 128.9 (C-2′ &C-6′ ), 130.2 (C-3′ &C-5′ ),
v
1
30.8 (C-1′ ), 132.1 (C-3′′&C-5′′), 132.7 (C-4), 134.1 (C-
v
A mixture of compound 5 (1 mmol) and p-chlorophenacyl
bromide (6) (1 mmol) in ethanol (10 ml) was sonicated for
4′ ), 135.2 (C-3), 136.3 (C-9), 145.6 (C-5′), 152.7 (C-4′′′),
157.4 C-3′), 156.1 (C-4′′), 160.2 (C-2′′); MS (m/z):
505.9747 [M + Na]. Anal. calcd. for C H ClN OS:
6
0–80 min. After completion of the reaction, the contents of
2
7
19
4
the flask were cooled and filtered on a Buchner funnel. It
was purified by column chromatography (silica gel 60–120
mesh) using ethyl acetate / hexane (1:3) as eluent.
C, 67.14; H, 3.97; N, 11.60%; found: C, 67.27; H, 4.02;
N, 11.85%.
3-(3′-(p-Chlorophenyl)-1-(4′′-(p-chlorophenyl)thiazol-2′
3
-(1-(4′′-(p-Chlorophenyl)thiazol-2′′-yl)-3′-phenyl-1H-
′-yl)-1H-pyrazol-5′-yl)-1H-indole (7d)
pyrazol-5′-yl)-1H-indole (7a)
m. p. 195–197 C; yield 81%; IR (KBr) (cm−1): 3257 (NH),
o
m. p. 175–176 C; yield 70%; IR (KBr) (cm−1): 3250 (NH),
o
1636 (C=C), 1585 (C=N); H NMR (400 MHz, DMSO-
d ): δ 6.92 (s, 1H, C -H), 6.98–7.69 (m, 14H, Ar–H, C2–H,
C -H), 10.91 (bs, 1H, NH); C NMR (100 MHz, DMSO-
d ): δ 1021.7 (C-4′), 113.1 (C-5′′), 114.2 (C-8), 120.4 (C-5),
123.5 (C-7), 127.7 (C-6), 128.4 (C-2), 129.3 (C-2′ &C-6′ ),
130.4 (C-3′ &C-5′ ), 130.7 (C-1′ ), 132.5 (C-3′′&C-5′′),
131.5 (C-2′′&C-6′′), 132.8 (C-4), 134.4 (C-4′ ), 134.9
(C-1′′), 135.9 (C-3), 136.8 (C-9), 138.2 (C-4′′), 146.3 (C-
5′), 155.7, (C-4′′), 158.9 (C-3′), 161.8 (C-2′′); MS (m/z):
510.3917 [M + Na]. Anal. calcd. for C H Cl N S: C,
1
1
1
629 (C=C), 1577 (C=N); H NMR (400 MHz, DMSO-
6
4′
1
3
d ): δ 6.75 (s, 1H, C ′-H), 6.92–7.58 (m, 15H, Ar–H, C2–H,
6
4
5′′
1
3
C -H), 10.09 (bs, 1H, NH); C NMR (100 MHz, DMSO-
5
′′
6
v
v
d6): δ 100.2 (C-4′), 112.5 (C-5′′), 112.8 (C-8), 119.6 (C-5),
v
v
v
1
1
1
22.4 (C-7), 126.5 (C-6), 127.2 (C-2′′&C-6′′), 127.9 (C-2),
28.8 (C-4′′), 129.6 (C-2′ &C-6′ ), 130.8 (C-3′ &C-5′ ),
v
v
v
v
v
v
31.5 (C-3′′&C-5′′), 132.4 (C-1′ ), 133.1 (C-4), 134.7 (C-1′
v
′
), 135.5 (C-4′ ), 136.7 (C-3), 137.2 (C-9), 145.1 (C-5′),
1
4
6
1
53.8 (C-4′′), 158.1 (C-3′), 160.3 (C-2′′); MS (m/z):
75.0749 [M + Na]. Anal. calcd. for C H ClN S: C,
8.94; H, 3.78; N, 12.37%; found: C, 69.01; H, 3.79; N,
2.52%.
2
6
16
2 4
64.07; H, 3.31; N, 11.49%; found: C, 64.01; H, 3.34; N,
2
6
17
4
11.60%.
3-(3′-(p-Bromophenyl)-1-(4′′-(p-chlorophenyl)thiazol-2′
3
-(1-(4′′-(p-Chlorophenyl)thiazol-2′′-yl)-3′-p-tolyl-1H-
′-yl)-1H-pyrazol-5′-yl)-1H-indole (7e)
pyrazol-5′-yl)-1H-indole (7b)
m. p. 212–215 C; yield 83%; IR (KBr) (cm−1): 3252 (NH),
o
m. p. 183–185 C; yield 72%; IR (KBr) (cm−1): 3255 (NH),
o
1632 (C=C), 1583 (C=N); H NMR (400 MHz DMSO-d ):
δ 6.80 (s, 1H, C -H), 6.40–7.61 (m, 14H, Ar–H, C2–H, C
1
6
1
1
633 (C=C), 1584 (C=N); H NMR (400 MHz, DMSO-
4
′
5′

Med Chem Res
1
3
′-H), 10.56 (bs, 1H, NH);
δ 101.3 (C-4′), 112.7 (C-5′′), 113.2 (C-8), 119.9 (C-5),
22.8 (C-7), 126.7 (C-6), 127.4 (C-4′′), 128.2 (C-2), 129.3
C NMR (100 MHz, DMSO-d6):
the absorbance of the test compound (containing methanolic
DPPH and test compound) and Ablank is the absorbance of
the blank (containing only methanolic DPPH). Tests were
carried out in triplicate.
1
v
v
v
v
(
1
C-2′ &C-6′ ), 129.8 (C-3′ &C-5′ ), 131.4 (C-2′′&C-6′′),
31.9 (C-1′ ), 132.8 (C-4), 133.7 (C-1′′), 135.1 (C-3′′&C-5′
), 135.8 (C-4′ ), 136.2 (C-3), 137.3 (C-9), 145.9 (C-5′),
v
v
′
Hydrogen peroxide (H O ) scavenging activity
2
2
1
5
5
1
54.2 (C-4′′), 158.2 (C-3′), 161.1 (C-2′′); MS (m/z):
54.8426 [M + Na]. Anal. calcd. for C H BrClN S: C,
A solution of H O (40 mM) was prepared in phosphate
2
6
16
4
2 2
−
1
8.72; H, 3.03; N, 10.53%; found: C, 58.81; H, 3.05; N,
0.69%.
buffer (pH 7.4). The 50, 75 and 100 μg ml concentrations
of the test compounds in 3.4 ml phosphate buffer were
added to H O solution (0.6 ml, 40 mM). The absorbance
2
2
3
1
-(3′-(p-Nitrophenyl)-1-(4′′-(p-chlorophenyl)thiazol-2′′-yl)-
H-pyrazol-5′-yl)-1H-indole (7f)
value of the reaction mixture was recorded at 230 nm.
Ascorbic acid was used as the standard. The percent of
scavenging of H O was calculated by the following
2
2
m. p. 206–208 C; yield 85%; IR (KBr) (cm−1): 3260 (NH),
1
d ): δ 6.93 (s, 1H, C ′-H), 7.00–7.73 (m, 14H, Ar–H, C2–H,
C -H), 11.09 (bs, 1H, NH); C NMR (100 MHz, DMSO-
o
equation
1
638 (C=C), 1587 (C=N); H NMR (400 MHz, DMSO-
ÂÀ
Á
Ã
%
of scavenging ¼ Acontrol ꢀ Asample =Ablank ꢁ 100;
6
4
1
3
5
′′
Where Acontrol is the absorbance of the control reaction
d6): δ 102.3 (C-4′), 113.6 (C-5′′), 114.8 (C-8), 120.8 (C-5),
(containing all reagents and ascorbic acid), Asample is the
1
1
5
1
23.0 (C-7), 123.9 (C-6), 128.2 (C-3′′&C-5′′), 128.9 (C-2),
29.5 (C-2′′&C-6′′), 130.8 (C-2′ &C-6′ ), 131.2 (C-3′ &C-
absorbance of the test compound (containing all reagents
and test compound) and Ablank is the absorbance of the
blank (containing only reagents). Tests were carried out in
triplicate.
v
v
v
v
v
v
′ ), 132.7 (C-1′ ), 133.7 (C-4), 134.6 (C-4′ ), 135.5 (C-3),
36.4 (C-9), 137.3 (C-1′′), 142.4 (C-4′′), 146.7 (C-5′), 156.3
(
+
C-4′′), 159.8 (C-3′), 162.3 (C-2′′); MS (m/z): 520.0601 [M
Na]. Anal. calcd. for C H ClN O S: C, 62.71; H, 3.24;
2
6
16
5 2
Nitric oxide scavenging activity
N, 14.06%; found: C, 62.78; H, 3.23; N, 14.18%.
NO radicals were generated from sodium nitroprusside. A
volume of 1 ml of sodium nitroprusside (10 mM) and 1.5 ml
of phosphate buffer saline (0.2 M, pH 7.4) were added to
different concentrations (50, 75 and 100 μg/ml) of the test
compounds and incubated for 150 min at 25 °C. After
incubation, 1 ml of the reaction mixture was treated with 1
ml of Griess reagent (1% sulfanilamide, 2% H PO and
Antioxidant activity
The compounds 4, 5 and 7 were assayed for antioxidant
property by DPPH (Burits and Bucar, 2000; Cuendet et al.
1
997), H O (Ruch et al. 1989) and nitric oxide (Green
2 2
et al. 1982; Marcocci et al. 1994) methods.
3
4
0
.1% naphthylethylenediamine dihydrochloride). The
2
,2-Diphenyl-1-picrylhydrazyl radical scavenging
absorbance of the chromatophore was measured at 546 nm.
Ascorbic acid was used as the standard. NO scavenging
activity was calculated by the following equation
activity
The hydrogen atom or electron donation ability of the
compounds was measured from the bleaching of the purple
colored methanol solution of DPPH radical. The spectro-
photometric assay uses the stable radical DPPH as a
reagent. To 4 ml of 0.004% (w/v) methanol solution of
DPPH, 1 ml of various concentrations of the test com-
pounds (50, 75 and 100 μg ml ) in methanol were added.
After a 30-min incubation period at room temperature, the
absorbance was read against blank at 517 nm. Ascorbic acid
was used as the standard. The percent of inhibition (I%) of
free radical production from DPPH was calculated by the
following equation
ÂÀ
Á
Ã
% of Scavenging ¼ Acontrol ꢀ Asample =Ablank ꢁ 100;
where Acontrol was the absorbance of the control reaction
(
containing all reagents and Ascorbic acid), Asample was the
absorbance of the test compound (containing all reagents
and test compound) and Ablank was the absorbance of the
blank (containing only reagents). Tests were carried out in
triplicate.
−
1
Acknowledgements The authors are grateful to University Grants
Commission, New Delhi for the sanction of UGC-BSR fellowship.
The authors are also thankful to Prof. Ch. Appa Rao, Department of
Bio-chemistry (SVU), for providing facilities to carry out the anti-
oxidant activity.
ÂÀ
Á
Ã
I% ¼ Acontrol ꢀ Asample =Ablank ꢁ 100;
where A
is the absorbance of the control reaction
control
Conflict of interest The authors declare that they have no competing
(
containing methanolic DPPH and ascorbic acid), Asample is
interests.

Med Chem Res
Biochemical and Biophysical Research Communications 201
2):748–755
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