Design, Synthesis, and Docking Studies of Novel Dimethyl Triazene Incorporated Thiazolyl Pyrazolines for Anticancer Activity

Article abstract of DOI:10.1002/jhet.3163

A novel series of dimethyl triazene incorporated thiazolyl pyrazolines have been designed on the basis of hybridization and also in support with combi-targeting approach. The designed compounds were synthesized through facile synthetic methods, and the co

Full text of DOI:10.1002/jhet.3163

Month 2018
Design, Synthesis, and Docking Studies of Novel Dimethyl Triazene
Incorporated Thiazolyl Pyrazolines for Anticancer Activity
a
Parameshwar Ravula,
Harinadha Babu Vamaraju,b Manichandrika Paturi,c Srinu Bodige,d Kali Charan Gulipalli,d and
*
J. N. Narendra Sharath Chandrae
aDepartment of Pharmaceutical Chemistry, Guru Nanak Institutions Technical Campus, School of Pharmacy, Jawaharlal
Nehru Technological University, Hyderabad, India
bMedicinal Chemistry Division, G. Pulla Reddy College of Pharmacy, Osmania University, Hyderabad, India
cDepartment of Pharmaceutical Chemistry, Bojjam Narsimulu Pharmacy College for Woman, Jawaharlal Nehru
Technological University, Hyderabad, India
dDepartment of Chemistry, KL University, Green fields, Vaddeswaram, Guntur, India
eDepartment of Pharmaceutical Chemistry, Bharat Institute of Technology, Pharmacy, Jawaharlal Nehru Technological
University, Hyderabad, India
*
E-mail: parmipharma@gmail.com
Received December 31, 2017
DOI 10.1002/jhet.3163
Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com).
A novel series of dimethyl triazene incorporated thiazolyl pyrazolines have been designed on the basis of
hybridization and also in support with combi-targeting approach. The designed compounds were synthesized
1
through facile synthetic methods, and the compounds were confirmed by H NMR, 13C NMR, MS, and
elemental analysis. Further, compounds were screened for in vitro anticancer activity against human breast
cancer (MCF-7) and human colon cancer (HT-29) cell lines by MTT assay. Among all the tested compounds,
compound 9b showed highest activity against both the cell lines in comparison with reference drug,
Cisplatin. In addition, the synthesized compounds were docked into VEGFR-2 kinase (PDB code: 2XIR)
to explore their binding interactions at the active site. The compounds showed essential key interactions
as that of known VEGFR-2 inhibitors, and hence, the synthesized compounds may be considered as molec-
ular scaffolds for anticancer activity.
J. Heterocyclic Chem., 00, 00 (2018).
INTRODUCTION
activities such as anticancer [3–6], antibacterial [7], anti-
inflammatory [8], and antiviral [9]. On the other hand,
pyrazoline is found to be a core structure in many of the
biological active compounds [10–13], and in recent years,
there have been several reports showing them as vascular
endothelial growth factor receptor-2 (VEGFR-2), B-raf,
cyclin dependent, and tyrosine kinase inhibitors for
anticancer activity [14–17]. In addition, thiazolyl
pyrazolines 10 also have drawn a great attention due to
their potent anticancer activity [18–20].
Cancer is a second leading cause of fatality worldwide
[1], and currently available anticancer drugs entail severe
side effects with drug resistance that lead to a severe
medical problem [2]. Therefore, there is an utmost need
to discover and develop novel anticancer agents with
improved tumor selectivity, safety, and efficiency. In
recent years, thiazole and their derivatives have been paid
greater attention because of their varied biological
© 2018 Wiley Periodicals, Inc.

P. Ravula, H. B. Vamaraju, M. Paturi, S. Bodige, K. C. Gulipalli, and J. N. Narendra Sharath Chandra Vol 000
Dacarbazine 11 is an imidazole derivative possessing
dimethyl triazene moiety at 5th position, and the drug is
proved to show anticancer activity by spontaneous
decomposition in the presence of cytochrome P450
enzyme generating methyl cation, which alkylates the N7
position of guanine [21]. In recent years, an interesting
novel strategy involving combi-targeting design of
molecules links triazene pharmacophore with two
molecules, namely, Gleevec and 4-anilinoquinazoline,
with improved cytotoxic activity by a dual mode of
action interacting with two biological targets, that is,
DNA and tyrosine kinase [22,23].
by incorporating dimethyl triazene pharmacophore into
thiazolyl pyrazoline motif with view to produce hybrid
molecules (Fig. 1). Furthermore, on the molecular design
level, various substituents were introduced on the
terminal phenyl ring with the purpose of exploring the
influence of substituents on the anticancer activity by
regulating the electronic and steric effects. Further
modifications were also performed at 5th position of
pyrazoline ring by using different substituted aldehydes,
in order to explain the structure activity relationships.
The synthesized compounds were screened for their
in vitro anticancer activity against two cancer cell lines,
namely, human colon cancer (HT-29) and human breast
adenocarcinoma (MCF-7) by MTT assay method. In
addition, a molecular docking study was performed for
synthesized compounds against VEGFR-2 kinase to
explore their binding interactions at the active site.
VEGFR-2 is pathologically involved in various processes
of angiogenesis, which include increased vascular
permeability, endothelial cell migration, survival, and
proliferation [26,27]. Consequently, in recent years, this
receptor has gained much scientific focus as a target for
the design of novel anticancer agents [28].
In view of the aforementioned facts and in continuation
of our research on pyrazoline derivatives [24,25], in the
present study, it is planned to design target compounds
RESULTS AND DISCUSSION
According to Scheme 1, (E)-1-(4-(3,3-dimethyltriaz-1-
en-1-yl)phenyl)ethanone 2 was prepared by diazotization
of 4-aminoacetophenone 1 with sodium nitrite in 6N HCl
followed by coupling with dimethylamine hydrochloride
as per the previously reported method [29]. Further, the
Figure 1. A design strategy of dimethyl triazene incorporated
thiazolyl pyrazolines (6a-9e). [Color figure can be viewed at
wileyonlinelibrary.com]
compound
2 was reacted with different aromatic
aldehydes in the presence of aq KOH solution (10%) as a
Scheme 1. Synthesis of the title compounds (6a-9e). Reagents and conditions: (a) NaNO2 (1.0 equiv), 6N HCl (10 vol), 5°C, 1 h; dimethylamine
hydrochloride (1.0 equiv), 15 to 20°C, 1 h; (b) aryl aldehydes (1.0 equiv), KOH solution (10%, 10 vol), rt, 16 h; (c) thiosemicarbazide (1.0 equiv),
KOH (1.0 equiv), ethanol, 80°C, 2 h (d) substituted phenacylbromide (1.0 equiv), DMF, 25°C, 2 h.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis and Docking Studies of Novel Thiazolyl Pyrazolines for
Anticancer Activity
base to give different chalcones (3a-3e). 1H NMR
spectrum of (E)-1-(4-((E)-3,3-dimethyltriaz-1-enyl)
C-4 and C-5 carbons of the pyrazoline ring showed
signals at δ 42.3 and δ 62.1, respectively, a peak at δ
175.8 due to C═S carbon, a peak at δ 154.7 for C═N of
pyrazoline carbon, and aromatic carbons appeared in the
range of δ 115.1–162.2. In addition, the mass spectrum of
compound 4a showed [M+H]+ peak at m/z 371.1, which
confirmed the proposed structure.
phenyl)-3-(4-fluorophenyl)prop-2-en-1-one 3a in CDCl3
showed two broad singlets at δ 3.57 and δ 3.26
corresponding to two methyl protons of triazene moiety
and the peaks for aromatic and –CH═CH– protons
appeared in the range of δ 7.11–8.03. Further, the
structure was confirmed from mass spectrum, which
showed [M+H]+ peak at m/z 298.1. The cyclization of
chalcones (3a-3e) with thiosemicarbazide under basic
conditions in ethanol afforded pyrazoline derivatives with
carbothioamide moiety (4a-4e). The resultant product 4a
was confirmed by two broad singlets at δ 8.02 and δ
7.84, which corresponds to NH2 protons of thioamide
group, and the aromatic protons appeared in the range of
δ 7.83–7.13. The two diastereotopic methylene protons at
position 4 and methine proton at position 5 of the
pyrazoline ring displayed three doublet of doublet
following ABX pattern of splitting, which clearly
indicated the formation of pyrazoline ring. The signals
for two methylene protons (HA and HB) appeared as two
doublet of doublet in the region of δ 3.84–3.92
(J = 29.6 Hz, 8.7 Hz) and δ 3.11–3.16 (clubbed with
methyl protons), respectively. The methine proton (HX)
also exhibited a doublet of doublet in the region of δ
5.89–5.93 (J = 14.8 Hz, 3.2 Hz), and two methyl proton
peaks of triazene moiety appeared at δ 3.52 and δ 3.16 in
1H NMR spectrum (400 MHz, DMSO-d6). The 13C NMR
(100 MHz, DMSO-d6) spectrum of compound 4a showed
a signal at δ 40.1 for CH3 carbon linked to nitrogen. The
Finally, the compounds (4a-4e) were reacted with
different phenacyl bromides (5a-5d) in DMF at 25°C by
stirring, which afforded the target compounds (6a-9e).
The compounds were fully characterized by 1H NMR, 13
C
NMR, mass, and elemental analysis. The disappearance of
thioamide protons at δ 8.02 and δ 7.84 and the appearance
of singlet signal at δ 6.81 due to lone proton of thiazole
1
ring in the H NMR spectrum of compound 6a clearly
indicated the formation of thiazole ring. The 13C NMR
(100 MHz, DMSO-d6) spectrum of compound 6a showed
two signals at δ 104.2 and 151.6, which could be
attributed to the C-5 and C-4 carbons of the thiazole ring,
the signals at δ 152.6 and δ 164.3 represented C═N of
pyrazoline and thiazole ring, respectively. Aromatic
carbons appeared in the range of δ 115.1–150.4 and the
absence of the characteristic signal of C═S at δ 175.8
indicating the formation of thiazole ring. Moreover, the
mass spectrum of compound 6a showed [M+H]+ peak at
m/z 471.1, which confirmed the structure.
Anticancer activity. The synthesized compounds (6a-9e)
were evaluated for their anticancer activity by in vitro
method using MTT assay against MCF-7 and HT-29 cell
lines, and their IC50 (μg/mL) values were presented in
Table 1
Physical data and in vitro anticancer activity of test compounds (6a-9e).
IC50 (μg/mL)
MCF-7
Compound
R
R1
Yield (%)
mp (°C)
HT-29
6a
6b
6c
6d
6e
7a
7b
7c
7d
7e
8a
8b
8c
8d
8e
9a
9b
9c
9d
9e
4-F-Phenyl
H
H
H
H
66
62
59
75
72
69
76
72
68
79
85
64
77
67
79
81
82
74
82
78
180–182
175–176
140–143
174–175
185–186
176–178
168–169
185–186
174–176
182–183
181–182
171–173
153–154
162–164
168–169
173–174
178–180
135–136
185–187
181–183
55.75
28.37
67.38
39.12
44.29
27.87
18.56
30.32
19.65
26.21
36.34
21.25
39.16
27.11
33.46
17.44
9.04
57.97
31.81
55.23
42.25
48.53
26.09
20.17
37.20
22.13
24.75
38.65
24.52
43.64
26.08
30.23
16.25
10.65
21.20
13.22
15.42
6.05
4-OCH3-Phenyl
Thiophen-2-yl
4-CH3-Phenyl
4-Cl-Phenyl
H
4-F-Phenyl
Br
Br
Br
Br
Br
OCH3
OCH3
OCH3
OCH3
OCH3
Cl
4-OCH3-Phenyl
Thiophen-2-yl
4-CH3-Phenyl
4-Cl-Phenyl
4-F-Phenyl
4-OCH3-Phenyl
Thiophen-2-yl
4-CH3-Phenyl
4-Cl-Phenyl
4-F-Phenyl
4-OCH3-Phenyl
Thiophen-2-yl
4-CH3-Phenyl
4-Cl-Phenyl
Cl
Cl
Cl
Cl
19.39
12.23
16.34
5.68
Cisplatin
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

P. Ravula, H. B. Vamaraju, M. Paturi, S. Bodige, K. C. Gulipalli, and J. N. Narendra Sharath Chandra Vol 000
Table 2
Interaction patterns of thiazolyl pyrazolines (6a-9e) with active site amino acids of VEGFR-2 in molecular docking studies.
Percentage
binding
Distance between ligand and active site
amino acid in Å
Type of
interaction
Compound
Active site amino acid interactions
LYS 868
ILE 888, LEU 889, ASP 1046, VAL 848
ASP 1046
ARG 1027
ARG 1027
ILE 888, LEU 889, VAL 916
ASP 1046
6a
25.7
—
40.1
84.0
—
2.62
—
2.87
2.32
—
Hydrogen
Hydrophobic
Hydrogen
Hydrogen
Stacking
Hydrophobic
Hydrogen
Hydrogen
Stacking
6b
6c
—
—
29.4
51.0
—
3.00
2.94
—
HIS 1026
ARG 1027
ILE 888, LEU 889, VAL 916, VAL 899
ASP 1046
HIS 1026
—
14.1
—
—
2.64
—
Hydrophobic
Hydrogen
Stacking
6d
6e
7a
7b
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 848, VAL 916
ASP 1046
LYS 868
ILE 888, LEU 1035, VAL 916, VAL 848
ASP 1046
ARG 1027
HIS 1026
ILE 888, LEU 889, VAL 916
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 848, PHE 1047
ASP 1046
ASP 1046
HIS 1026
—
12.2
—
—
10.4
—
—
2.77
—
—
2.65
—
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Hydrogen
Hydrogen
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Hydrogen
Hydrogen
Stacking
—
—
79.9
80.5
29.6
—
10.2
—
—
20.1
—
—
10.3
—
—
14.5
—
2.87
2.75
2.73
—
2.75
—
—
2.71
—
—
2.65
—
—
3.16
—
7c
7d
7e
8a
8b
—
—
10.0
61.4
24.7
—
2.65
2.77
3.14
—
LYS 868
ILE 888, VAL 899, VAL 848, VAL 916
ARG 1027
ARG 1027
—
23.6
—
—
3.08
—
Hydrophobic
Hydrogen
Stacking
8c
LYS 868
—
—
Stacking
ILE 888, LEU 889, VAL 916, ILE 1025
ARG 1027
—
—
—
—
Hydrophobic
Stacking
8d
8e
9a
9b
9c
9d
LYS 868
ILE 888, LEU 889, VAL 916
ARG 1027
LYS 868
ILE 888, LEU 889, VAL 916, VAL 899
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
LYS 868
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
ARG 1027
ILE 888, LEU 889, VAL 916
ASP 1046
—
—
—
—
—
20.3
—
—
36.2
—
—
38.8
—
—
20.0
—
—
—
—
—
2.72
—
—
2.63
—
—
2.86
—
—
2.71
Stacking
Hydrophobic
Stacking
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
Stacking
Hydrophobic
Hydrogen
(Continues)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis and Docking Studies of Novel Thiazolyl Pyrazolines for
Anticancer Activity
Table 2
(Continued)
Percentage
binding
Distance between ligand and active site
Type of
interaction
Compound
Active site amino acid interactions
amino acid in Å
ILE 888, LEU 889, VAL 916, LEU 1035
ASP 1046
HIS 1026
ARG 1027
—
20.8
62.9
—
—
3.09
2.87
—
Hydrophobic
Hydrogen
Hydrogen
9e
Stacking
ILE 888, LEU 889, VAL 916, VAL 899
—
—
Hydrophobic
Figure 2. (a) Two-dimensional representation of the interacting mode of 9b with VEGFR-2 kinase. (b) Three-dimensional structural model of compound
9b into VEGFR-2 kinase. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

P. Ravula, H. B. Vamaraju, M. Paturi, S. Bodige, K. C. Gulipalli, and J. N. Narendra Sharath Chandra Vol 000
Table 1. Among the tested compounds, 9b showed highest
activity against both the cell lines in comparison with
reference drug, Cisplatin. Compound 9b (R = 4-OCH3-
Phenyl, R1 = Cl) elicited potent inhibitory activity against
MCF-7 and HT-29 cell lines with IC50 values of 9.04 and
10.65 μg/mL, respectively. Additionally, compound 8b
(IC50 = 21.25 μg/mL) owning a substitution at R1 position
is an electron-donating group (R1 = OCH3), but when it is
replaced by electron-withdrawing group (R1 = Cl, Br) in
known VEGFR-2 inhibitors and hence, the synthesized
compounds considered as promising inhibitors for
proliferation. The two-dimensional and three-dimensional
representations of compound 9b were shown in Figure 2,
and the remaining compounds docking representations
were given in the Supporting Information.
CONCLUSIONS
compounds 9b (IC50
=
9.04 μg/mL) and 7b
(IC50 = 18.56 μg/mL), the activity increases against MCF-
7 cell line. The aryl ring, when replaced with a hetero
cyclic ring (6c, 7c, 8c, and 9c), led to the reduction in
anticancer activity. The activity in increasing order for R1
substitution is H < OCH3 < Br < Cl and for R
In summary, a series of dimethyl triazene incorporated
thiazolyl pyrazolines (6a-9e) were designed and
synthesized through facile synthetic methods. The
1
compounds were confirmed by H NMR, 13C NMR, MS,
and elemental analysis. They were subjected to in vitro
anticancer activity against two cancer cell lines by MTT
assay. Among the tested compounds, 9b showed highest
activity against HT-29 and MCF-7 cell lines in
comparison with reference drug, Cisplatin. From the
activity data, it was observed that the presence of
electron-withdrawing groups at R1 position showed
increases in activity, while electron-donating groups at R1
have shown a decrease in activity. Moreover, the
synthesized compounds were docked into VEGFR-2
kinase to explore their binding interactions at the active
site. The compounds showed similar and essential key
interactions as that of known VEGFR-2 inhibitors.
Further studies are being conducted to elucidate the
mechanism of action of these compounds and
optimization of their anticancer activity.
substitution is thiophen-2-yl
< 4-F-Phenyl < 4-Cl-
Phenyl < 4-CH3-Phenyl < 4-OCH3-Phenyl against MCF-7
and HT-29 cell lines. In the present study, MTT assay was
used only as a preliminary tool for the selection of the
compounds for anticancer activity. These selected
compounds may prove to be more potent in the in vivo
screening as dimethyl triazene moiety is expected to
undergo decomposition in the presence of cytochrome
P450 to release CH3 cations that alkylate DNA. Further
studies are being conducted to elucidate the mechanism of
action of these compounds and optimization of their
anticancer activity.
Molecular docking.
In the present study, the
synthesized compounds were docked into VEGFR-2
kinase (PDB code: 2XIR) to explore their binding
interactions at the active site. Docking studies revealed
that compounds (6a-9e) interacted with amino acids such
ASP 1046, LYS 868, ARG 1027, and HIS 1026, which
are also found to interact with known VEGFR-2
inhibitors [30–33]. Further, N-2 of the pyrazoline ring or
N-2 of trizene interacts with H-atom of amino acid
backbone of ASP 1046 via a hydrogen bond, and phenyl
ring of test compounds showed stacking interaction with
LYS 868. Moreover, thiazolyl pyrazoline is surrounded
by the hydrophobic residues such as ILE 888, LEU 889,
VAL 899, VAL 916, and LEU 1035 indicating its role in
hydrophobic interactions in the active site of VEGFR-2.
These interactions underscore the importance of
inhibitory capacity against VEGFR-2. Ligand 9b
exhibited effective interaction fit with ASP 1046 of
36.2% binding at a distance of 2.63 Å; triazenyl phenyl
ring formed stacking interaction with LYS 868. Apart
from this, the compound was surrounded by GLU 885,
ILE 888, VAL 916, LEU 889, and LEU 1035 and also
showed potent in vitro anticancer activity in their series.
Data pertaining to the interaction of thiazolyl pyrazolines
(6a-9e) with amino acids on VEGFR-2 active site were
given in Table 2 indicating that all the tested compounds
have shown akin and essential key interactions as that of
EXPERIMENTAL
All chemicals were purchased from Sigma-Aldrich,
Merck, and were used without further purification. All
melting points were uncorrected and determined in one
end open capillary tubes using Guna Digital Melting
Point apparatus. Elemental analyses were performed on a
1
PerkinElmer 240 CHN elemental analyzer. H and 13C
NMR spectra were recorded on a Bruker AMX 300
spectrometer operating at 400/300 MHz for 1H and
1
100 MHz for 13C NMR. The H and 13C NMR chemical
shifts were expressed in parts per million (ppm) with
reference to tetramethylsilane (TMS). Mass spectra were
recorded on the Agilent Technologies mass spectrometer.
TLC was performed using E. Merck 0.25 mm silica gel
plates, and visualization of spots was accomplished with
UV light.
Synthesis of (E)-1-(4-(3,3-dimethyltriaz-1-en-1-yl)phenyl)
ethanone 2.
4-Aminoacetophenone
1
(5.00 g,
37.0 mmol) was dissolved in 6N hydrochloric acid
(50.0 mL). The solution was cooled to 5°C in an ice bath,
and a solution of sodium nitrite (2.58 g, 37.0 mmol) in
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DOI 10.1002/jhet

Month 2018
Synthesis and Docking Studies of Novel Thiazolyl Pyrazolines for
Anticancer Activity
water (10 mL) was added at such a rate that the temperature
did not rise above 10°C. To the resulting solution of the
diazonium salt was added dimethylamine hydrochloride
(3.01 g, 37.0 mmol) portion wise and stirred at 15–20°C
for 1 h. Then the reaction mixture was neutralized with aq
NaOH (10%) solution. The obtained solid was filtered and
washed thoroughly with water to remove any alkaline
impurities. The crude product was recrystallized from
toluene to afford (E)-1-(4-(3,3-dimethyltriaz-1-en-1-yl)
phenyl)ethanone (2) as an off white solid. (6.1 g, 86%),
J = 8.4 Hz), 7.28 (d, 2H, J = 8.0 Hz), 3.56 (s, 3H),
3.21 (s, 3H), 2.35 (s, 3H). MS m/z: 294.1 [M+H]+;
Anal. Calcd C18H19N3OS: C, 73.69; H, 6.53; N, 14.32;
Found: C, 73.66; H, 6.57; N, 14.35.
(E)-3-(4-Chlorophenyl)-1-(4-((E)-3,3-dimethyltriaz-1-enyl)
phenyl)prop-2-en-1-one 3e. White solid, mp 135–137°C,
1
yield: 78%, H NMR (400 MHz, CDCl3): δ 8.02 (dd, 2H,
J = 8.4 Hz, 1.6 Hz), 7.79 (d, 1H, J = 15.6 Hz), 7.62–7.60
(m, 2H), 7.52–7.45 (m, 3H), 6.94 (dd, 2H, J = 8.8 Hz,
2.0 Hz), 3.86 (s, 3H), 3.56 (bs, 3H), 3.26 (bs, 3H). MS
m/z: 314.1 [M+H]+; Anal. Calcd C17H16ClN3O: C, 65.07;
H, 5.14; N, 13.39; Found: C, 65.10; H, 5.17; N, 13.37.
1
mp 125–126°C, H NMR (400 MHz, CDCl3): δ 7.94 (d,
2H, J = 8.4 Hz), 7.47 (d, 2H, J = 8.8 Hz), 3.55 (bs, 3H),
3.24 (bs, 3H), 2.59 (s, 3H). MS m/z: 192.1 [M+H]+; Anal.
Calcd C10H13N3O: C, 62.81; H, 6.85; N, 21.97; Found: C,
62.84; H, 6.82; N, 21.99.
General procedure for the synthesis of pyrazoline
carbothioamides (4a-4e). A mixture of chalcone (3a-3e)
(3.5 mmol), thiosemicarbazide (3.5 mmol), and potassium
hydroxide (3.5 mmol) in ethanol (10 mL) was heated to
reflux for 2 h at 80°C. After completion of reaction
(monitored by TLC), the reaction mixture was cooled and
the product obtained was filtered, washed with water, and
recrystallized from ethanol to afford pyrazoline
General procedure for the synthesis of chalcones (3a-3e).
To a stirred solution of the (E)-1-(4-(3,3-dimethyltriaz-1-
en-1-yl)phenyl)ethanone 2 (1.00 g, 5.23 mmol) and the
appropriate aryl aldehyde (5.23 mmol) in 10.0 mL of
ethanol, 10% KOH solution (10 mL) was added. The
carbothioamides (4a-4e).
reaction mixture was stirred for 16
h at room
(E)-3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide
temperature. The solid obtained was filtered, washed with
water, and finally recrystallized from ethanol to afford the
chalcones (3a-3e).
1
4a. Brown solid, mp 150–152°C, yield: 79%, H NMR
(400 MHz, DMSO-d6): δ 8.02 (bs, 1H), 7.84 (bs, 1H),
7.83 (d, 2H, J = 8.4 Hz), 7.38 (d, 2H, J = 8.8 Hz), 7.16–
7.13 (m, 4H), 5.91 (dd, 1H, J = 14.8 Hz, 3.2 Hz), 3.88
(dd, 1H, J = 29.6 Hz, 8.7 Hz), 3.52 (bs, 3H), 3.16–3.11
(m, 4H). 13C NMR (100 MHz, DMSO-d6): δ 175.8,
162.2, 159.8, 154.7, 152.1, 139.1, 128.0, 127.3, 120.0,
115.2, 115.0, 62.1, 42.3, 40.1. MS m/z: 371.1 [M+H]+;
Anal. Calcd C18H19FN6S: C, 58.36; H, 5.17; N, 22.69;
(E)-1-(4-((E)-3,3-Dimethyltriaz-1-enyl)phenyl)-3-(4-
fluorophenyl)prop-2-en-1-one 3a. Brown solid, mp 130–
1
133°C, yield: 80%, H NMR (400 MHz, CDCl3): δ 8.03
(dd, 2H, J = 6.8 Hz, 1.6 Hz), 7.78 (d, 1H, J = 15.6 Hz),
7.65–7.62 (m, 2H), 7.54–7.49 (m, 3H), 7.11 (t, 2H,
J = 17.2 Hz), 3.57 (bs, 3H), 3.26 (bs, 3H). MS m/z:
298.1 [M+H]+; Anal. Calcd C17H16FN3O: C, 68.67; H,
5.42; N, 14.13; Found: C, 68.65; H, 5.45; N, 14.17.
(E)-1-(4-((E)-3,3-Dimethyltriaz-1-enyl)phenyl)-3-(4-
Found: C, 58.39; H, 5.14; N, 22.66.
(E)-3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide
methoxyphenyl)prop-2-en-1-one 3b.
Off white solid, mp
1
133–134°C, yield: 78%, H NMR (400 MHz, CDCl3): δ
8.02 (dd, 2H, J = 8.4 Hz, 1.6 Hz), 7.79 (d, 1H,
J = 15.6 Hz), 7.62–7.60 (m, 2H), 7.52–7.45 (m, 3H),
6.94 (dd, 2H, J = 8.8 Hz, 2.0 Hz), 3.86 (s, 3H), 3.56 (bs,
3H), 3.26 (bs, 3H). MS m/z: 310.1 [M+H]+; Anal. Calcd
C18H19N3O2: C, 69.88; H, 6.19; N, 13.58; Found: C,
4b.
Off white solid, mp 137–140°C, yield: 77%, 1H
NMR (400 MHz, CDCl3): δ 7.69 (d, 2H, J = 8.4 Hz),
7.46 (d, 2H, J = 8.4 Hz), 7.17 (d, 2H, J = 8.8 Hz), 6.85
(d, 2H, J = 8.4 Hz), 5.98 (dd, 1H, J = 14.8 Hz, 3.6 Hz),
3.86–3.81 (m, 1H), 3.77 (s, 3H), 3.54 (bs, 3H), 3.23–3.17
(m, 4H). 13C NMR (100 MHz, DMSO-d6): δ 175.7,
158.1, 154.8, 152.1, 135.0, 128.0, 127.3, 126.6, 120.0,
113.7, 62.2, 55.0, 42.3, 40.1. MS m/z: 383.1 [M+H]+;
Anal. Calcd C19H22N6OS: C, 59.66; H, 5.80; N, 21.97;
Found: C, 59.68; H, 5.77; N, 21.99.
69.85; H, 6.17; N, 13.61.
(E)-1-(4-((E)-3,3-Dimethyltriaz-1-enyl)phenyl)-3-(thiophen-
2-yl)prop-2-en-1-one 3c. Off white solid, mp 124–126°C,
1
yield: 79%, H NMR (400 MHz, DMSO-d6): δ 8.10 (d,
2H, J = 8.4 Hz), 7.90 (d, 1H, J = 15.2 Hz), 7.79 (d, 1H,
J = 5.2 Hz), 7.68 (d, 1H, J = 3.6 Hz), 7.59 (d, 1H,
J = 15.6 Hz), 7.46 (d, 1H, J = 8.4 Hz), 7.20 (dd, 2H,
J = 8.8 Hz, 4.0 Hz), 3.56 (s, 3H), 3.21 (s, 3H). MS m/z:
286.1 [M+H]+; Anal. Calcd C15H15N3OS: C, 63.13; H,
(E)-3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(thiophen-2-yl)-
4,5-dihydro-1H-pyrazole-1-carbothioamide 4c.
Off white
solid, mp 136–137°C, yield: 76%, 1H NMR
(400 MHz, DMSO-d6): δ 8.04 (bs, 1H), 7.86 (d, 2H,
J = 11.2 Hz), 7.83 (bs, 1H), 7.41–7.35 (m, 3H), 6.98–
6.91 (m, 2H), 6.22 (d, 1H, J = 12.4 Hz), 3.86 (dd,
1H, J = 38.0 Hz, 15.2 Hz), 3.52 (bs, 3H), 3.37–3.18
(m, 4H). 13C NMR (100 MHz, DMSO-d6): δ 175.6,
155.1, 152.2, 145.3, 128.1, 127.1, 126.4, 124.5, 124.4,
120.1, 58.5, 42.0, 40.1. MS m/z: 359.1 [M+H]+; Anal.
5.30; N, 14.73; Found: C, 63.10; H, 5.33; N, 14.77.
(E)-1-(4-((E)-3,3-Dimethyltriaz-1-enyl)phenyl)-3-p-tolylprop-
2-en-1-one 3d. Brown solid, mp 122–123°C, yield: 75%,
1H NMR (400 MHz, DMSO-d6): 8.16 (d, 2H,
J = 8.8 Hz), 7.92 (d, 1H, J = 15.6 Hz), 7.79 (d, 2H,
J = 8.4 Hz), 7.70 (d, 1H, J = 15.2 Hz), 7.47 (d, 2H,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

P. Ravula, H. B. Vamaraju, M. Paturi, S. Bodige, K. C. Gulipalli, and J. N. Narendra Sharath Chandra Vol 000
Calcd C16H18N6S2: C, 53.61; H, 5.06; N, 23.44; Found:
C, 53.64; H, 5.04; N, 23.47.
(E)-3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-p-tolyl-4,5-
J = 14.8 Hz), 6.87 (d, 1H, J = 8.8 Hz), 6.79 (s, 1H), 5.62
(dd, 1H, J = 18.4 Hz, 6.4 Hz), 3.87 (dd, 1H, J = 29.2 Hz,
12.0 Hz), 3.78 (s, 3H), 3.37–3.30 (m, 7H). 13C NMR
(100 MHz, DMSO-d6): δ 163.7, 158.3, 158.1, 152.0,
151.1, 149.9, 133.4, 127.5, 127.1, 127.0, 126.8, 126.4,
119.9, 113.4, 101.4, 63.2, 54.6, 42.6, 39.7. MS m/z:
483.1 [M+H]+; Anal. Calcd C27H26N6OS: C, 67.20; H,
dihydro-1H-pyrazole-1-carbothioamide 4d.
Brown solid,
mp 133–135°C, yield: 75%, 1H NMR (400 MHz,
CDCl3): δ 7.68 (d, 2H, J = 8.4 Hz), 7.45 (d, 2H,
J = 8.8 Hz), 7.13 (s, 4H), 5.99 (dd, 1H, J = 14.8 Hz,
3.2 Hz), 3.82 (dd, 1H, J = 28.8 Hz, 11.6 Hz), 3.54 (bs,
3H), 3.29–3.17 (m, 4H), 2.31 (s, 3H). 13C NMR
(100 MHz, DMSO-d6): δ 175.7, 154.7, 152.1, 140.0,
135.9, 128.9, 128.0, 127.3, 125.2, 120.0, 62.5, 42.4,
40.1, 20.5. MS m/z: 367.1 [M+H]+; Anal. Calcd
C19H22N6S: C, 62.27; H, 6.05; N, 22.93; Found: C,
5.43; N, 17.41; Found: C, 67.24; H, 5.47; N, 17.43.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(thiophen-2-
yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazole 6c. White
1
solid, mp 140–143°C, yield: 59%, H NMR (400 MHz,
CDCl3): δ 7.80–7.73 (m, 4H), 7.48 (d, 2H, J = 8.4 Hz),
7.35 (t, 2H, J = 15.2 Hz), 7.27–7.20 (m, 3H), 6.97–6.95
(m, 1H), 6.85 (s, 1H), 5.96 (dd, 1H, J = 17.6 Hz,
6.0 Hz), 3.90 (dd, 1H, J = 28.8 Hz, 11.6 Hz), 3.62–3.40
(m, 7H). 13C NMR (100 MHz, DMSO-d6): δ 163.9,
158.3, 152.3, 151.3, 149.9, 143.6, 126.99, 126.90, 126.4,
126.2, 125.3, 125.0, 119.9, 113.4, 101.9, 59.1, 42.3, 39.7.
MS m/z: 459.2 [M+H]+; Anal. Calcd C24H22N6S2: C,
62.86; H, 4.84; N, 18.33; Found: C, 62.83; H, 4.81; N,
62.25; H, 6.09; N, 22.95.
(E)-5-(4-Chlorophenyl)-3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide 4e.
Brown solid, mp 144–146°C, yield: 78%, 1H NMR
(300 MHz, CDCl3): δ 7.67 (d, 2H, J = 8.4 Hz), 7.46 (d,
2H, J = 8.7 Hz), 7.30 (d, 2H, J = 8.7 Hz), 7.18 (d, 2H,
J = 8.4 Hz), 6.02 (dd, 1H, J = 15.0 Hz, 3.6 Hz), 3.84
(dd, 1H, J = 29.4 Hz, 11.4 Hz), 3.51–3.14 (m, 7H). 13C
NMR (100 MHz, DMSO-d6): δ 175.7, 154.7, 152.1,
141.9, 131.3, 128.4, 128.1, 127.3, 127.1, 120.0, 62.2,
42.1, 40.1. MS m/z: 387.1 [M+H]+; Anal. Calcd
C18H19ClN6S: C, 55.88; H, 4.95; N, 21.72; Found: C,
55.85; H, 4.97; N, 21.75.
18.36.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-p-tolyl-4,5-
dihydro-1H-pyrazol-1-yl)-4-phenylthiazole 6d.
Off white
1
solid, mp 174–175°C, yield: 75%, H NMR (400 MHz,
CDCl3): δ 7.74–7.68 (m, 4H), 7.46 (d, 2H, J = 8.8 Hz),
7.33–7.29 (m, 4H), 7.23–7.14 (m, 3H), 6.79 (s, 1H), 5.62
(dd, 1H, J = 18.4 Hz, 6.4 Hz), 3.88 (dd, 1H, J = 29.6 Hz,
12.0 Hz), 3.48–3.30 (m, 7H), 2.31 (s, 3H). 13C NMR
(100 MHz, DMSO-d6): δ 164.6, 159.2, 159.0, 152.9,
152.0, 150.8, 134.3, 128.4, 128.0, 127.9, 127.7, 127.3,
120.8, 114.3, 102.3, 64.0, 43.5, 40.6, 20.5. MS m/z:
467.2 [M+H]+; Anal. Calcd C27H26N6S: C, 69.50; H,
General procedure for the synthesis of the title compounds
(6a-9e). A mixture of pyrazoline carbothioamide (4a-4e)
(0.5 mmol) and appropriate substituted phenacyl bromide
(5a-5d) (0.5 mmol) in DMF (5.0 mL) was stirred for 2 h
at 25°C. After completion of reaction, the reaction
mixture was diluted with a saturated sodium chloride
solution. The obtained solid was filtered and washed
thoroughly with water. The crude product was purified by
column chromatography (ethyl acetate/hexane) to afford
5.62; N, 18.01; Found: C, 69.52; H, 5.60; N, 18.04.
(E)-2-(5-(4-Chlorophenyl)-3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazole 6e.
Brown solid, mp 185–186°C, yield: 72%, 1H NMR
(400 MHz, CDCl3): δ 7.72–7.66 (m, 4H), 7.45 (d, 2H,
J = 8.4 Hz), 7.35–7.27 (m, 4H), 7.21–7.18 (m, 1H), 6.85
(d, 2H, J = 8.8 Hz), 6.77 (s, 1H), 5.60 (dd, 1H,
J = 18.4 Hz, 6.4 Hz), 3.87 (dd, 1H, J = 29.6 Hz,
12.0 Hz), 3.35–3.27 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 163.5, 158.1, 151.9, 151.0, 149.6, 140.2,
131.3, 127.9, 127.8, 126.6, 126.1, 119.6, 113.2, 101.4,
62.8, 42.3, 39.5. MS m/z: 487.0 [M+H]+; Anal. Calcd
C26H23ClN6S: C, 64.12; H, 4.76; N, 17.26; Found: C,
the title compounds (6a-9e).
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazole
1
6a. Brown solid, mp 180–182°C, yield: 66%, H NMR
(400 MHz, CDCl3): δ 7.73 (d, 2H, J = 8.4 Hz), 7.66 (d,
2H, J = 7.2 Hz), 7.47 (d, 2H, J = 8.8 Hz), 7.42 (dd, 2H,
J = 13.6 Hz, 5.2 Hz), 7.31 (t, 2H, J = 15.6 Hz), 7.22 (d,
1H, J = 7.6 Hz), 7.04 (t, 2H, J = 17.2 Hz), 6.81 (s, 1H),
5.64 (dd, 1H, J = 18.8 Hz, 7.2 Hz), 3.91 (dd, 1H,
J = 29.6 Hz, 12.0 Hz), 3.62–3.19 (m, 7H). 13C NMR
(100 MHz, DMSO-d6): δ 164.3, 152.6, 151.6, 150.4,
134.4, 128.8, 128.7, 128.4, 127.4, 127.3, 125.4, 120.2,
115.3, 115.1, 104.2, 63.5, 43.0, 40.1. MS m/z: 471.1 [M
+H]+; Anal. Calcd C26H23FN6S: C, 66.36; H, 4.93; N,
64.10; H, 4.79; N, 17.29.
(E)-4-(4-Bromophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)
thiazole 7a. Off white solid, mp 176–178°C, yield: 69%,
1H NMR (400 MHz, CDCl3): δ 7.72 (d, 2H, J = 8.8 Hz),
7.66 (dd, 2H, J = 8.4 Hz, 1.6 Hz), 7.47 (d, 2H,
17.86; Found: C, 66.39; H, 4.96; N, 17.88.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazole
J
= 6.0 Hz), 7.48–7.38 (m, 4H), 7.03 (t, 2H,
1
J = 17.6 Hz), 6.81 (s, 1H), 5.62 (dd, 1H, J = 18.8 Hz,
7.2 Hz), 3.91 (dd, 1H, J = 29.2 Hz, 12.0 Hz), 3.34–
3.28 (m, 7H). 13C NMR (100 MHz, DMSO-d6): δ
6b. White solid, mp 175–176°C, yield: 62%, H NMR
(400 MHz, CDCl3): δ 7.74–7.68 (m, 4H), 7.47 (d, 2H,
J
= 8.4 Hz), 7.38–7.29 (m, 4H), 7.23 (t, 1H,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis and Docking Studies of Novel Thiazolyl Pyrazolines for
Anticancer Activity
163.9, 152.3, 151.3, 150.0, 134.0, 128.4, 128.3, 128.1,
127.1, 126.9, 125.0, 119.9, 115.0, 114.8, 103.8, 63.1,
42.7, 39.7. MS m/z: 549.1 [M+H]+; Anal. Calcd
C26H22BrFN6S: C, 56.83; H, 4.04; N, 15.30; Found: C,
63.2, 42.6, 39.8. MS m/z: 564.9 [M+H]+; Anal. Calcd
C26H22BrClN6S: C, 55.18; H, 3.92; N, 14.85; Found: C,
55.21; H, 3.90; N, 14.82.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-
56.87; H, 4.01; N, 15.34.
methoxyphenyl)thiazole 8a.
Off white solid, mp 181–
(E)-4-(4-Bromophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)
thiazole 7b. White solid, mp 168–169°C, yield: 76%, 1H
1
182°C, yield: 85%, H NMR (400 MHz, CDCl3): δ 7.72
(d, 2H, J = 8.4 Hz), 7.59 (dd, 2H, J = 10.0 Hz, 1.6 Hz),
7.47 (dd, 2H, J = 9.6 Hz, 1.6 Hz), 7.42–7.39 (m, 2H),
7.06–7.01 (m, 2H), 6.86–6.67 (m, 2H), 6.67 (s, 1H), 5.63
(dd, 1H, J = 18.0 Hz, 6.0 Hz), 3.98–3.81 (m, 1H), 3.80
(s, 3H) 3.59–3.27 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 164.9, 153.3, 152.2, 151.0, 135.0, 129.4,
129.3, 129.0, 128.1, 127.9, 126.0, 120.9, 115.9, 115.7,
104.8, 64.1, 55.0, 43.6, 40.7. MS m/z: 501.2 [M+H]+;
Anal. Calcd C27H25FN6OS: C, 64.78; H, 5.03; N, 16.79;
NMR (400 MHz, CDCl3): δ 7.73 (dd, 2H, J = 8.4 Hz,
1.6 Hz), 7.56 (dd, 2H, J = 8.8 Hz, 4.8 Hz), 7.48–7.42 (m,
4H), 7.35 (dd, 2H, J = 8.8 Hz, 2.0 Hz), 6.87 (d, 1H,
J = 8.8 Hz), 6.79 (s, 1H), 5.59 (dd, 1H, J = 18.4 Hz,
6.4 Hz), 3.87 (dd, 1H, J = 29.2 Hz, 12.0 Hz), 3.78 (s,
3H), 3.36–3.30 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 163.3, 157.8, 157.7, 151.5, 150.7, 149.4,
133.0, 127.1, 126.6, 126.5, 126.3, 126.3, 125.9, 119.4,
112.9, 101.1, 62.7, 54.1, 42.1, 39.2. MS m/z: 561.0 [M
+H]+; Anal. Calcd C27H25BrN6OS: C, 57.75; H, 4.49; N,
Found: C, 64.75; H, 5.04; N, 16.76.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(4-
methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-
methoxyphenyl)thiazole 8b. Brown solid, mp 171–173°C,
14.97; Found: C, 57.78; H, 4.46; N, 14.99.
(E)-4-(4-Bromophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(thiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole
1
yield: 64%, H NMR (400 MHz, CDCl3): δ 7.73 (d, 2H,
1
7c. White solid, mp 185–186°C, yield: 72%, H NMR
J = 8.4 Hz), 7.62 (d, 2H, J = 8.4 Hz), 7.47 (d, 2H,
J = 8.4 Hz), 7.36 (d, 2H, J = 8.0 Hz), 6.89–6.84 (m, 4H),
6.66 (s, 1H), 5.62 (dd, 1H, J = 18.4 Hz, 6.4 Hz), 3.91–
3.87 (m, 1H), 3.81 (s, 3H), 3.78 (s, 3H), 3.49–3.09 (m,
7H). 13C NMR (100 MHz, DMSO-d6): δ 164.1, 158.7,
158.5, 152.4, 151.5, 150.2, 133.8, 127.9, 127.5, 127.4,
127.2, 126.8, 120.2, 113.8, 101.8, 63.5, 55.0, 55.0, 43.0,
40.1. MS m/z: 513.0 [M+H]+; Anal. Calcd C28H28N6O2S:
C, 65.60; H, 5.51; N, 16.39; Found: C, 65.64; H, 5.54;
(400 MHz, CDCl3): δ 7.75–7.73 (m, 2H), 7.65 (dd, 2H,
J = 8.8 Hz, 2.0 Hz), 7.49–7.46 (m, 4H), 7.22–7.18 (m,
2H), 6.97–6.94 (m, 1H), 6.84 (s, 1H), 5.94 (dd, 1H,
J = 17.6 Hz, 6.0 Hz), 3.91 (dd, 1H, J = 28.8 Hz,
11.6 Hz), 3.55–3.40 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 164.2, 158.7, 152.6, 151.6, 150.2, 143.9,
127.3, 127.2, 126.8, 126.6, 125.7, 125.4, 120.2, 113.8,
102.3, 59.5, 42.7, 40.0. MS m/z: 537.0 [M+H]+; Anal.
Calcd C24H21BrN6S2: C, 53.63; H, 3.94; N, 15.64;
N, 16.36.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-(thiophen-2-
yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-methoxyphenyl)thiazole
8c. Brown solid, mp 153–154°C, yield: 77%, H NMR
Found: C, 53.60; H, 3.97; N, 15.66.
(E)-4-(4-Bromophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-p-tolyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole 7d.
1
Brown solid, mp 174–176°C, yield: 68%, 1H NMR
(400 MHz, CDCl3): δ 7.73–7.71 (m, 2H), 7.54 (d, 2H,
(400 MHz, CDCl3): δ 7.67 (d, 2H, J = 8.8 Hz), 7.64 (d,
2H, J = 8.8 Hz), 7.41 (d, 2H, J = 8.8 Hz), 7.15–7.13 (m,
2H), 6.90–6.88 (m, 1H), 6.87–6.81 (m, H), 6.81 (s, 1H),
5.89 (dd, 1H, J = 18.0 Hz, 6.4 Hz), 3.85–3.81 (m, 1H),
3.75 (s, 3H), 3.59–3.25 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 164.3, 158.7, 152.7, 151.7, 150.3, 144.0,
127.4, 127.3, 126.8, 126.6, 125.7, 125.5, 120.3, 113.8,
102.3, 59.6, 55.0, 42.7, 40.1. MS m/z: 489.0 [M+H]+;
Anal. Calcd C25H24N6OS2: C, 61.45; H, 4.95; N, 17.20;
J
= 8.8 Hz), 7.48–7.41 (m, 4H), 7.31 (d, 2H,
J = 8.0 Hz), 7.15 (d, 2H, J = 8.0 Hz), 6.79 (s, 1H),
5.60 (dd, 1H, J = 18.8 Hz, 6.8 Hz), 3.89 (dd, 1H,
J = 29.2 Hz, 12.0 Hz), 3.58–3.25 (m, 7H), 2.32 (s, 3H).
13C NMR (100 MHz, DMSO-d6): δ 164.3, 158.8,
158.7, 152.5, 151.7, 150.4, 134.0, 128.1, 127.7, 127.5,
127.3, 126.9, 120.4, 113.9, 102.0, 63.7, 43.1, 40.3,
20.1. MS m/z: 545.0 [M+H]+; Anal. Calcd
C27H25BrN6S: C, 59.45; H, 4.62; N, 15.41; Found: C,
Found: C, 61.41; H, 4.98; N, 17.23.
(E)-2-(3-(4-(3,3-Dimethyltriaz-1-enyl)phenyl)-5-p-tolyl-4,5-
dihydro-1H-pyrazol-1-yl)-4-(4-methoxyphenyl)thiazole 8d.
59.48; H, 4.60; N, 15.45.
Brown solid, mp 162–164°C, yield: 67%, 1H NMR
(400 MHz, CDCl3): δ 7.72 (d, 2H, J = 8.4 Hz), 7.62 (d,
2H, J = 8.8 Hz), 7.47 (d, 2H, J = 8.8 Hz), 7.15 (d, 2H,
J = 8.0 Hz), 6.85 (d, 2H, J = 9.2 Hz), 6.65 (s, 1H), 5.62
(dd, 1H, J = 18.8 Hz, 6.8 Hz), 3.92–3.88 (m, 1H), 3.81
(s, 3H), 3.49–3.29 (m, 7H), 2.32 (s, 3H). 13C NMR
(100 MHz, DMSO-d6): δ 165.0, 159.5, 159.4, 153.2,
152.4, 151.1, 134.7, 128.8, 128.3, 128.2, 128.0, 127.6,
121.1, 114.6, 102.7, 64.4, 55.9, 43.8, 40.9, 20.4. MS m/z:
(E)-4-(4-Bromophenyl)-2-(5-(4-chlorophenyl)-3-(4-(3,3-
dimethyltriaz-1-enyl)phenyl)-4,5-dihydro-1H-pyrazol-1-yl)
thiazole 7e. Brown solid, mp 182–183°C, yield: 79%, 1H
NMR (400 MHz, CDCl3): δ 7.72 (d, 2H, J = 8.4 Hz), 7.53–
7.42 (m, 6H), 7.37–7.31 (m, 4H), 6.81 (s, 1H), 5.59 (dd,
1H, J = 18.8 Hz, 6.8 Hz), 3.90 (dd, 1H, J = 29.2 Hz,
12.0 Hz), 3.59–3.26 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 163.8, 158.4, 152.2, 151.3, 149.9, 140.5,
131.6, 128.3, 128.1, 126.9, 126.4, 119.9, 113.5, 101.8,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

P. Ravula, H. B. Vamaraju, M. Paturi, S. Bodige, K. C. Gulipalli, and J. N. Narendra Sharath Chandra Vol 000
497.2 [M+H]+; Anal. Calcd C28H28N6OS: C, 67.72; H,
5.68; N, 16.92; Found: C, 67.70; H, 5.71; N, 16.96.
(E)-4-(4-Chlorophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-p-tolyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole 9d.
Brown solid, mp 185–187°C, yield: 82%, 1H NMR
(400 MHz, CDCl3): δ 7.72 (dd, 2H, J = 8.8 Hz, 2.0 Hz),
7.61 (dd, 2H, J = 8.8 Hz, 2.0 Hz), 7.46 (dd, 2H,
J = 8.4 Hz, 2.0 Hz), 7.32–7.28 (m, 4H), 7.15 (d, 2H,
J = 8.0 Hz), 6.78 (s, 1H), 5.61 (dd, 1H, J = 18.8 Hz,
6.8 Hz), 3.89 (dd, 1H, J = 29.2 Hz, 12.0 Hz), 3.65–3.30
(m, 7H), 2.32 (s, 3H). 13C NMR (100 MHz, DMSO-d6):
δ 164.2, 158.8, 158.6, 152.5, 151.6, 150.4, 133.9, 128.0,
127.6, 127.5, 127.3, 126.9, 120.4, 113.9, 101.9, 63.7,
43.1, 40.2, 20.5. MS m/z: 501.1 [M+H]+; Anal. Calcd
C27H25ClN6S: C, 64.72; H, 5.03; N, 16.77; Found: C,
(E)-2-(5-(4-Chlorophenyl)-3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-methoxyphenyl)
thiazole 8e. Brown solid, mp 168–169°C, yield: 79%, 1H
NMR (400 MHz, CDCl3): δ 7.72 (d, 2H, J = 8.8 Hz), 7.59
(dd, 2H, J = 8.8 Hz, 2.0 Hz), 7.47 (d, 2H, J = 8.4 Hz),
7.38–7.31 (m, 4H), 6.85 (d, 2H, J = 8.8 Hz), 6.68 (s,
1H), 5.61 (dd, 1H, J = 18.8 Hz, 6.8 Hz), 3.94–3.90 (m,
1H), 3.81 (s, 3H), 3.40–3.12 (m, 7H). 13C NMR
(100 MHz, DMSO-d6): δ 164.1, 158.7, 152.5, 151.6,
150.2, 140.9, 131.9, 128.6, 128.4, 127.3, 126.7, 120.2,
113.8, 102.1, 63.5, 55.0, 42.9, 40.1. MS m/z: 517.2 [M
+H]+; Anal. Calcd C27H25ClN6OS: C, 62.72; H, 4.87; N,
64.75; H, 5.07; N, 16.74.
16.25; Found: C, 62.75; H, 4.83; N, 16.28.
(E)-4-(4-Chlorophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)
(E)-4-(4-Chlorophenyl)-2-(5-(4-chlorophenyl)-3-(4-(3,3-
dimethyltriaz-1-enyl)phenyl)-4,5-dihydro-1H-pyrazol-1-yl)
thiazole 9e. Brown solid, mp 181–183°C, yield: 78%, 1H
thiazole 9a.
Off white solid, mp 173–174°C, yield:
NMR (400 MHz, CDCl3): δ 7.71 (dd, 2H, J = 8.8 Hz,
2.0 Hz), 7.58 (dd, 2H, J = 8.8 Hz, 2.0 Hz), 7.48 (d, 2H,
J = 8.8 Hz), 7.37–7.28 (m, 6H), 6.80 (s, 1H), 5.60 (dd,
1H, J = 18.8 Hz, 6.8 Hz), 3.90 (dd, 1H, J = 29.6 Hz,
12.0 Hz), 3.67–3.26 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 164.0, 158.6, 152.4, 151.5, 150.1, 140.7,
131.8, 128.5, 128.3, 127.1, 126.6, 120.1, 113.7, 102.0,
63.4, 42.8, 40.0. MS m/z: 521.0 [M+H]+; Anal. Calcd
C26H22Cl2N6S: C, 59.88; H, 4.25; N, 16.12; Found: C,
59.85; H, 4.28; N, 16.16.
81%, 1H NMR (400 MHz, CDCl3): δ 7.71 (dd, 2H,
J = 8.4 Hz, 1.6 Hz), 7.51–7.36 (m, 8H), 7.02 (t, 2H,
J = 17.2 Hz), 6.79 (s, 1H), 5.59 (dd, 1H, J = 18.8 Hz,
7.2 Hz), 3.89 (dd, 1H, J = 29.6 Hz, 12.0 Hz), 3.32–
3.26 (m, 7H). 13C NMR (100 MHz, DMSO-d6): δ
164.1, 152.5, 151.5, 150.2, 134.2, 128.6, 128.5, 128.3,
127.3, 127.1, 125.2, 120.1, 115.2, 115.0, 104.0, 63.3,
42.9, 39.9. MS m/z: 505.0 [M+H]+; Anal. Calcd
C26H22ClFN6S: C, 61.84; H, 4.39; N, 16.64; Found: C,
61.81; H, 4.36; N, 16.67.
In vitro anticancer activity. The anticancer activity of all
the 20 compounds was evaluated against two cancer cell
lines, namely, HT-29 and MCF-7. The cell lines were
procured from National Center for Cell Sciences, Pune,
India. All tumor cells were grown in DMEM media supple-
mented with 10% heat inactivated fetal bovine serum
(FBS), 100 mg/mL streptomycin, 100 IU/mL penicillin,
and 2 mM glutamine. All cell lines were maintained under
humidified atmosphere with 5% CO2 at 37°C for 48 h.Af-
ter incubation, cells (5 × 103 cells/well) were inoculated in
96-well plate and cultured with or without compounds at
different concentrations in triplicates for 24 h in a final vol-
ume of 200 μL. Afterwards, the medium was removed, and
20 μL of MTT (5 mg/mL in PBS) was added. After 3 h in-
cubation at 37 °C, 100 μL of DMSO was added to each
well, and the plate was agitated for 1 min. The absorbance
was read at 570 nm with a multi-well plate reader (Victor3,
PerkinElmer), and IC50 values were calculated [34,35].
(E)-4-(4-Chlorophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)
thiazole 9b. White solid, mp 178–180°C, yield: 82%, H
1
NMR (400 MHz, CDCl3): δ 7.73 (d, 2H, J = 8.4 Hz),
7.62 (d, 2H, J = 8.8 Hz), 7.47 (d, 2H, J = 8.8 Hz),
7.36 (d, 2H, J = 8.8 Hz), 7.29–7.27 (m, 2H), 6.88 (d,
1H, J = 8.8 Hz), 6.78 (s, 1H), 5.62 (dd, 1H,
J = 20.8 Hz, 9.6 Hz), 3.93–3.85 (m, 2H), 3.78 (s, 3H),
3.49–3.30 (m, 7H). 13C NMR (100 MHz, DMSO-d6): δ
163.5, 158.1, 157.9, 151.8, 150.9, 149.6, 133.2, 127.3,
126.9, 126.8, 126.6, 126.2, 119.6, 113.2, 101.2, 62.9,
54.4, 42.3, 39.5. MS m/z: 517.1 [M+H]+; Anal. Calcd
C27H25ClN6OS: C, 62.72; H, 4.87; N, 16.25; Found: C,
62.75; H, 4.84; N, 16.28.
(E)-4-(4-Chlorophenyl)-2-(3-(4-(3,3-dimethyltriaz-1-enyl)
phenyl)-5-(thiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole
1
9c. White solid, mp 135–136°C, yield: 74%, H NMR
(400 MHz, CDCl3): δ 7.66 (d, 2H, J = 8.8 Hz), 7.56 (d,
2H, J = 8.8 Hz), 7.41–7.37 (m, 4H), 7.14–7.10 (m, 2H),
6.87 (dd, 1H, J = 8.8 Hz, 3.6 Hz), 6.76 (s, 1H), 5.86 (dd,
1H, J = 17.6 Hz, 6.0 Hz), 3.91 (dd, 1H, J = 28.8 Hz,
11.6 Hz), 3.46–3.32 (m, 7H). 13C NMR (100 MHz,
DMSO-d6): δ 164.0, 158.5, 152.4, 151.4, 150.0, 143.7,
127.1, 127.0, 126.6, 126.4, 125.5, 125.2, 120.0, 113.6,
102.0, 59.3, 42.5, 39.8. MS m/z: 493.1 [M+H]+; Anal.
Calcd C24H21ClN6S2: C, 58.46; H, 4.29; N, 17.05;
Found: C, 58.48; H, 4.26; N, 17.08.
Molecular docking.
Molecular docking for test
compounds (6a-9e) was performed on Windows 2002
operating system with the help of the MOE software
2008.10 version. VEGFR-2 kinase was obtained from the
Swedish protein data bank (PDB code: 2XIR), and the
target receptor was visualized using sequence option, and
further co-factors were deleted. The partial charge of
VEGFR-2 receptor was calculated and readjusted, using
the force field method AMBER 99. Later, the receptor
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Synthesis and Docking Studies of Novel Thiazolyl Pyrazolines for
Anticancer Activity
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was allowed for 3D protonation at cutoff 12.0, and
subsequently, hydrogens were added as required for
standard geometry and the VEGFR-2 kinase was
subjected to energy minimization by using the force field
MMFF94x method at 0.01 kJ/mol gradients. The target
structures were drawn using a builder module of MOE
software and balanced the partial charges using Hamilton
MMFF94 force field method, and subsequently, 3D
protonated and hydrogen were added according to
standard geometry. Thiazolyl pyrazoline structures (6a-
9e) were energy minimized using force field MMFF94x
application of MOE software at cutoff 12 at 0.01 kJ/mol
gradient, and 6.0 Å grid was generated on the active site
of the enzyme. Molecular docking analysis was carried
out by opting simulation mode following the dock
module on the selected active site amino acids with the
help of sequence option, and eventually docked by
selecting options, such as receptor and solvent, selected
residues, alpha triangle, affinity dG, force field
refinement, and best 30 pose. Finally, molecular docking
results were obtained, out of the 30 best posed
conformers resulted for each chemical structure. Among
these, one of the best conformers of the ligand was
retained. The resultant best pose score computed values
in the series were used for analysis of molecular docking
and interaction [24].
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Acknowledgments. We are grateful for the financial support from
University Grants Commission, New Delhi, India (MRP 6254/15/
SERO/UGC). The authors are also thankful to the management of
Guru Nanak Institutions Technical Campus, School of Pharmacy,
Hyderabad, India, for providing facilities.
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SUPPORTING INFORMATION
[9] Wang, N. Y.; Xu, Y.; Zuo, W. Q.; Xiao, K. J.; Liu, L.; Zeng, X.
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Additional Supporting Information may be found online
in the supporting information tab for this article.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet