2,5,6-Trisubstituted imidazo[2,1-b][1,3,4]thiadiazoles: Search for antihyperlipidemic agents

Article abstract of DOI:10.1016/j.ejmech.2013.04.020

A novel series of 2,5,6-trisubstituted imidazo[2,1-b][1,3,4]thiadiazoles 4 (a-d) and 7(a-i) were rationally designed through QSAR based pharmacophore approach and synthesized from 5-(1,3-benzodioxol-5-yl)-[1,3,4]thiadiazol-2-amine (1). The structures of t

Full text of DOI:10.1016/j.ejmech.2013.04.020

European Journal of Medicinal Chemistry 65 (2013) 119e133
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
2,5,6-Trisubstituted imidazo[2,1-b][1,3,4]thiadiazoles: Search for
antihyperlipidemic agents
,
c
d
Harun M. Patel a, Malleshappa N. Noolvi b , Anjali Goyal , B.S. Thippeswamy
*
a Division of Computer Aided Drug Design, Department of Pharmaceutical Chemistry, R.C. Patel Institute of Pharmaceutical Education and Research, Shirpur,
Dhule 425405, Maharashtra, India
b Department of Pharmaceutical Chemistry, Shree Dhanvantary Pharmacy College, Kim, Surat 3941110, Gujarat, India
c Department of Pharmaceutical Chemistry, ASBASJSM College of Pharmacy, Bela, Ropar 140111, Punjab, India
d Department of Pharmacology, Sree Siddagang College of Pharmacy, Tumkur 572102, Karnataka, India
a r t i c l e i n f o
a b s t r a c t
Article history:
A novel series of 2,5,6-trisubstituted imidazo[2,1-b][1,3,4]thiadiazoles 4(aed) and 7(aei) were rationally
designed through QSAR based pharmacophore approach and synthesized from 5-(1,3-benzodioxol-5-yl)-
[1,3,4]thiadiazol-2-amine (1). The structures of these compounds were established by IR, 1H NMR, 13C
NMR, HRMS technique. All the compounds were evaluated for their in vitro antihyperlipidemic activity
using trition induced hyperlipidemic model. The newly synthesized title compound 7d, 7e and 7h
showed a significant decrease in the serum, TCH, TG LDL and VLDL values along with an increase in
serum HDL levels as compared to standard drug Fenofibrate. The treated groups also showed significant
decrease in the atherogenic index, LDL:HDL risk ratios and the level of SGOT, SGPT and ALP activities
compared to cholesterol induced hyperlipidemic control group.
Received 11 October 2012
Received in revised form
4 April 2013
Accepted 8 April 2013
Available online 18 April 2013
Keywords:
Synthesis imidazo[2,1-b][1,3,4]thiadiazole
Hyperlipedimia
QSAR
Ó 2013 Elsevier Masson SAS. All rights reserved.
Atherogenic index
1. Introduction
pharmacological treatments can significantly reduce morbidity
from CHD, thus providing a causal role for cholesterol in coronary
Hyperlipidemia is
a
major cause of atherosclerosis and
events. During recent years, there have been intense investigations
on thiadiazole and imidazo[2,1-b][1,3,4]thiadiazole compounds
carried out, many of which are known to possess interesting bio-
logical properties such as antimicrobial [6,7], antitubercular [8,9],
anti-inflammatory [10,11], anticonvulsant [12,13], antihypertensive
[14,15], and anticancer activities [16].
In view of the above facts and in continuation of our research for
various biologically active molecules [9,17e19] and encouraging
QSAR and docking study reported in the literature by Kathia M.
Honorio et al. [20,21] has prompted us to synthesize novel mole-
cules of fused imidazo[2,1-b][1,3,4]thiadiazole and screen for their
in vitro antihyperlipidemic activity (Fig. 1).
atherosclerosis-associated conditions such as coronary heart dis-
ease, ischemic cerebrovascular disease, and peripheral vascular
disease [1]. A causal relationship between the elevated plasma
lipids and the development of atherosclerotic plaques has been
well established. Hyperlipidemia is an elevation of lipids in the
bloodstream and these lipids include fats, fatty acids, cholesterol,
cholesterol esters, phospholipids, and triglycerides [2,3]. Therefore,
agents that increase HDL cholesterol concentration in the blood and
thereby ratio of HDL cholesterol to total cholesterol (H/C) would
have promising therapeutic utility as antihyperlipidemic agents
[4,5]. Despite significant medical advances, heart attacks due to
coronary artery disease (due to atherosclerosis that affects the ar-
teries supplying blood to the heart) and stroke (due to athero-
sclerosis that affects the arteries supplying blood to the brain) are
responsible for more deaths than all other causes combined. In
addition to this; different cholesterol lowering drugs or non-
2. Rationale and designing
The Farnesoid-X-Receptor (FXR) is an attractive drug target for
the development of novel therapeutic agents for the treatment of
dyslipidemia and cholestasis. Hologram Quantitative Structure
Activity Relationship (HQSAR) studies were conducted on a series
of potent FXR activators originated from natural product-like li-
braries by Kathia M. Honorio et al. [21]. In HQSAR, it is possible to
visualize the individual contribution to activity of each atom in a
* Corresponding author. Tel.: þ91 8141175355; fax: þ91 1881263655.
E-mail
addresses:
mnoolvi@yahoo.co.uk,
mallesh7301@rediffmail.com
(M.N. Noolvi).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.04.020

120
H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Fig. 1. Synthesized fused imidazo[2,1-b][1,3,4]thiadiazoles based upon QSAR model proposed by Kathia M. Honorio et al. [21].
given molecule of the data set through the generation of contri-
bution maps. They suggested that one fragment of the molecular
structure, represented by the 1,3-benzodioxol moiety, is strongly
related to the biological activity having pEC50 ¼ 7.72 as shown in
Fig. 1. An important role of a QSAR model, besides predicting the
activities of untested molecules, is to provide hints about what
molecular fragments are directly related to biological activity. This
information, combined with knowledge of synthetic chemistry,
promoted us to the synthesis new 2,5,6-trisubstituted imidazo[2,1-
b][1,3,4]thiadiazoles containing 1,3-benzodioxol moiety as novel
FXR ligands having improved potency.
Siddagang College of Pharmacy, Tumkur (Karnataka) India. The
animal were grouped and housed in polyacrylic cages
(38 ꢀ 23 ꢀ 10 cm) with not more than six animals per cage and
maintained under standard laboratory conditions (temperature
25 ꢁ 2 ꢂC) with dark and light cycle (14/10 h). They were allowed
free access to standard dry pellet diet and water ad libitum. The
mice were acclimatized to laboratory condition for 10 days before
commencement of experiment. The experimental protocol was
approved by Institutional Animal Ethical Committee (IAEC No.
SSCP/IAEC/2010-11/52) constituted under CPCSEA.
4.2. Induction of hyperlipidemia
3. Chemistry
Hyperlipidemia was induced in Wistar albino rats by single
intraperitoneal injection of freshly prepared solution of Triton-X-
100 (100 mg/kg) in physiological saline solution after overnight
fasting for 18 h. The animals were divided into four groups of six
rats each. The first group was given standard pellet diet, water and
orally administered with 5% CMC. The second group was given a
single dose of triton administered at a dose of 100 mg/kg, i.p. After
72 h of triton injection, this group received a daily dose of 5% CMC
(p.o.) for 7 days. The third group was administered a daily dose of
synthesized compounds 250 mg/kg suspended in 5% CMC (p.o.) for
7 days, after inducing hyperlipidemia. Fourth group was adminis-
tered with the standard Fenofibrate 250 mg/kg (p.o.) for 7 days [24].
Synthesis of fused imidazo[2,1-b][1,3,4]thiadiazole 4(aed) and
7(aei) is outlined in Scheme 1. 5-(Benzo[d][1,3]dioxol-5-yl)-[1,3,4]
thiadiazol-2-amine 1 is prepared as per the reported method [22].
Condensation of 1 with respective bromoacetyl compound in
ethanol and dimethylformamide yields imidazo thiadiazole 2 and 5
in good yields [23]. VilsmeiereHack reaction of imidazo thiadiazole
2 and 5, in DMF and POCl3 provided respective 5-formyl derivatives
3 and 6 [23]. The aldehyde functional group when treated with
amines gave the corresponding imine derivatives 4(aed) and 7(ae
i). The detail reaction mechanism is depicted in physical data is
given in Table 1.
4. Pharmacology
4.3. Collection of blood
4.1. Experimental animals
At the end of experimental period, blood was collected by retro
orbital sinus puncture, under mild ether anesthesia. The serum was
separated by centrifugation at 2500ꢀ g for 15 min at 4 ꢂC. Then
serum samples were collected and assayed for total cholesterol,
Wistar albino adult male rats weighing 200e250 g were ob-
tained from the animal house department of pharmacology, Sree

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
121
Scheme 1. General synthetic route for the synthesis of the compounds 4(aed) and 7(aei).
triglycerides, phospholipids, high-density lipoprotein (HDL), low-
density lipoprotein (LDL), very low-density lipoprotein (VLDL) us-
ing standard protocol methods used for various biochemical ex-
periments. The animals were then sacrificed and the liver collected
[25].
image analyzer (ProÒ Plus Version 4.5. Media Cybernetics, MD,
USA) on each section.
4.5. Biochemical analysis
The serum was assayed for total cholesterol, triglycerides, high-
density lipoprotein (HDL), low-density lipoprotein (LDL), very low-
density lipoprotein (VLDL) as per the reported method [27e29].
Hepatotoxicity was evaluated by measuring alanine transferase
[30], aspartate transferase [31] and alkaline phosphatase [32] levels
in serum.
4.4. Histopathological observation of liver
Animals were euthanized under ether anesthesia and the liver
was dissected out immediately. For histopathological analysis, the
liver tissues were fixed in 10% formalin at room temperature. The
tissue was embedded in paraffin, sectioned by 3e4
m
m thickness,
5. Docking study
and mounted on the glass microscope slides using standard his-
tological techniques [26]. The sections were stained with
hematoxylin-eosin and examined using light microscopy at 200ꢀ
magnitude. These light-microscopic fields were assessed by an
The molecular docking tool, GLIDE (Schordinger Inc., USA)
(2009) was used for ligand docking studies into the FXR binding
pocket. The crystal structures of FXR were obtained from protein

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H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Table 1
Physical data of synthesized compounds 4(aed) and 7(aei).
Sr. No.
Compound
Molecular formula
Molecular weight
424.4744
Melting point (ꢂC)
Yield (%)
4a
C24H16N4O2S
123e125
67
4b
C24H15BrN4O2S
503.3705
170e173
78
4c
C25H18N4O3S
454.5004
170e175
62
4d
C25H18N4O2S
438.5010
158e163
56
7a
C25H17ClN4O2S
472.9461
158e162
68
7b
C25H17ClN4O3S
488.9455
234e239
78
7c
C25H17ClN4O2S
472.9461
205e210
82

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
123
Table 1 (continued )
Sr. No.
Compound
Molecular formula
Molecular weight
Melting point (ꢂC)
Yield (%)
7d
C24H16ClN5O4S2
537.9979
223e228
73
7e
C25H15ClN4O4S
502.9290
234e238
76
7f
C25H16ClN5O3S
501.9442
198e201
78
7g
C24H14ClN5O4S
503.9171
225e228
63
7h
C24H13Cl2FN4O2S
511.3550
245e248
69
7i
C24H14BrClN4O2S
537.8156
190e192
64
data bank (PDB ID: 1OSH) [33]. The protein preparation was carried
out using ‘protein preparation wizard’ in Maestro 9.0 in two steps,
preparation and refinement. After ensuring chemical correctness,
water molecules in the crystal structures were deleted and hy-
drogens were added, where they were missing. Using the OPLS
2005 force field energy of crystal structure was minimized [34].
Grids were defined centering them on the ligand in the crystal
structure using the default box size. The ligands were built using
maestro build panel and prepared by Ligprep 2.2 module which
produce the low energy conformer of ligands using OPLS 2005 force
field. The low energy conformation of the ligands was selected and
was docked into the grid generated from protein structures using
standard precision (SP) docking mode. The final evaluation is done
with glide score (docking score) and single best pose is generated as
the output for particular ligand.
6. Results and discussion
The formation of 5-(benzo[d][1,3]dioxol-5-yl)-[1,3,4]thiadiazol-
2-amine (1) was confirmed by IR spectra, which showed the

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H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
presence of amine (AreNH2) band and the absence of carbonyl
stretching of carboxylic acid. Structures of imidazo thiadiazole de-
rivatives (2 and 5) were established by the absence of amine (Are
NH2) band in IR spectra and appearance of imidazole proton (H-5)
other hand imidazo[2,1-b][1,3,4]thiadiazoles containing oxygen in
the form of sulphonamide, carboxylic acid, amide and nitro group
shows H-bonding interaction with backbone of HIE-298 and SER-
336. These interactions underscore the importance of both nitro-
gen and oxygen as hydrogen bond acceptor for binding and the
subsequent agonistic capacity. The results of this virtual screening
could support the postulation that our active compounds may bind
on the same enzyme target where Fexaramine binds. With
respective to the glide score Compound 7e, 7d and 7f shows highest
binding affinity with glide score of ꢃ9.89, ꢃ9.24 and ꢃ8.32 kcal/
mol indicating the importance of oxygen as hydrogen bond
acceptor as shown in Table 4 and Fig. 3.
around
d
8.21 and 8.31 in the 1H NMR spectra. IR spectra of alde-
hydes (3 and 6) displayed a sharp band for carbonyl stretching
frequency around 1724 cmꢃ1 and the signal for imidazole proton
(H-5) in 1H NMR spectrum was absent. A new signal for aldehydic
proton was observed around
d
10.00 in the 1H NMR spectra, thus
substantiating the formation of imidazo[2,1-b][1,3,4]thiadiazole-5-
carbaldehydes. The absence of aldehydic protons and presence of
the imine proton (CH]N) around
d
8.5 in 1H NMR spectra of the
product supported the formation of the title compounds 4(aed)
and 7(aei). The 13C NMR and HRMS data of these compounds
further confirmed the assigned structures.
7. Structure activity relationship
The main biochemical parameters recommended by the Na-
tional Cholesterol Education Programme (NCEP) guidelines (2002)
for lipid screening i.e. Total Cholesterol (TCH), Triglycerides, Low
Density Lipoprotein (LDL), Very Low Density Lipoprotein (VLDL)
and High Density Lipoprotein (HDL) were evaluated from the
serum Wistar albino rats [35]. The present investigation shows that
all triton induced rats displayed hyperlipidemia as shown by their
elevated levels of serum cholesterol, triglyceride, VLDL, LDL and the
reduction in the HDL level. In cholesterol induced hyperlipidemic
model, among 4(aed) and 7(aei) the groups treated with the 7d, 7e
and 7h and Fenofibrate demonstrated a significant decrease in the
serum TCH, TG, LDL and VLD besides an increase in serum HDL
levels when compared to trition induced hyperlipidemic control
group (Table 2). The cardiac risk ratios recommended by NCEP
guidelines (2002) were estimated by calculating the TCH: HDL ratio
(Atherogenic Index) and LDL:HDL ratio [36]. The groups treated
with 7d, 7e and 7h also demonstrated significant decrease in
atherogenic index and LDL:HDL risk ratios as shown in Table 2.
Hepatotoxicity of some potent compounds were further evaluated
by measuring alanine transferase, aspartate transferase and alka-
line phosphatase levels in serum and a remarkable decrease in the
level of SGOT, SGPT and ALP activities when compared to choles-
terol induced hyperlipidemic control group (Table 3). In cholesterol
induced hyperlipidemic model, the histopathological studies were
conducted in the liver section of rats to observe the histopatho-
logical changes (Fig. 2). Fig. 2 illustrates the protective action of the
synthesized compounds, among them compound 7d, 7e and 7h
treated group shows mild cytoplasmic fatty infiltration and mild
granular degeneration, on the other hand compound 7h and 7i
treated group shows mild cytoplasmic fatty infiltration and mild to
moderate granular degeneration compared to that of Fenofibrate.
Docking study was carried out for the target compounds into
EGFR using GLIDE (Schordinger Inc., USA) (2009). The crystal
structure of the enzyme with Fexaramine (PDB: 1OSH) was ob-
tained from protein data bank PDB [33]. Our compounds were
modeled by positioning them in the co-crystallized ligand Fexar-
amine binding site in accordance with the published crystal
structures [37]. The entire complex was then subjected to alternate
cycles of minimization and dynamics. The intent was to get a
satisfactory structure for the complex that was consistent with the
published crystal structure [38,39]. From the comparative docking
study of our compounds with Fexaramine lead compounds we
could observe how our compounds might bind to the FXR binding
site, based on the knowledge of the structure of similar active sites.
We redocked Fexaramine into the active site of the enzyme and
then we replaced with our compounds in order to compare the
binding mode of both co-crystallized ligand and the test com-
pound. These docking studies have revealed that the most of the
synthesized compounds shows H-bonding with HIE-298 amino
acid backbone via N-6 of imidazo[2,1-b][1,3,4]thiadiazoles. On the
A brief investigation of the structureeactivity relationship (SAR)
revealed that the compounds with 4-choloro phenyl substitution at
6th position of imidazo[2,1-b][1,3,4]thiadiazole nucleus is more
potent than the plane phenyl substitution as it is obvious by
comparing in vitro antihyperlipidemic activity of 7(aei) and 4(ae
d). In case of compound 7(aei), the derivatives with electron
withdrawing substituent at 5th position of imidazo[2,1-b][1,3,4]
thiadiazole, found to significantly affect over the lipid parameters
(7e, 7g, 7h and 7i). On the other hand electron-donating substitu-
ent at 5th position is having diminishing effect on biological activity
(Compound 4d, 7a and 7c).
8. Conclusion
A new series of 2,5,6-trisubstituted imidazo[2,1-b][1,3,4]thia-
diazoles 4(aed) and 7(aei) were rationally designed through QSAR
base pharmacophore approach. All the compounds were evaluated
for their in vitro antihyperlipidemic activity, among them 7d, 7e
and 7h showed a significant decrease in the serum, TC, LDL, VLDL
and TG values along with an increase in serum HDL levels as
compared to standard drug Fenofibrate. The treated groups also
showed significant decrease in the atherogenic index, LDL:HDL risk
ratios which are a reliable risk assessment factor of coronary heart
disease. Hepatotoxicity was evaluated by measuring alanine
transferase, aspartate transferase and alkaline phosphatase levels
in serum and no compound was found to be hepatotoxic. Possible
improvements in the antihyperlipidemic activity can be further
achieved by slight modifications in the substituent’s and/or addi-
tional structural activity investigations. These preliminary encour-
aging results of biological screening of the tested compounds could
offer an excellent framework in this field that may lead to discovery
of potent antihyperlipidemic agent.
9. Experimental protocols
All chemicals and solvents were supplied by Merck, S.D. Fine
Chemical Limited, Mumbai. All the solvents were distilled and dried
before use. The reactions were monitored with the help of thin-
layer chromatography using pre-coated aluminum sheets with
GF254 silica gel, 0.2 mm layer thickness (E. Merck). The solvents
used throughout the experiment for running TLC were toluene,
ethyl acetate and formic acid in the ratio of 5:4:1, chloroform and
methanol in the ratio of 9.5:0.5 and 9:1 as developing solvents. UV
Cabinet was used for the visualization of TLC spots. Melting points
of the synthesized compounds were recorded on the Veego (VMP-
MP) melting point apparatus. IR spectrum was acquired on a Shi-
madzu Infra Red Spectrometer, (model FTIR-8400S). Both 1H NMR
(DMSO) and 13C NMR (DMSO) spectra of the synthesized com-
pounds were performed with Bruker Avance-II 400 NMR Spec-
trometer operating at 400 MHz in SAIF, Punjab University

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
125
Table 2
Data of total lipid profile (TCH, TG, VLDL, LDL and HDL).
Compound code
Compound
Parameter (mg/dl)
TCH TG
Atherogenic index LDL/HDL
VLDL
LDL
HDL
TCH/HDL
Normal
Positive
Control
Standard
71.17 ꢁ 0.612 76.19 ꢁ 0.718 14.03 ꢁ 0.689
21.19 ꢁ 0.721
36.5 ꢁ 0.821
1.94
0.58
4.90
126.5 ꢁ 1.234a
138 ꢁ 1.345a
29 ꢁ 0.3781a 78.5 ꢁ 1.623a
16 ꢁ 0.4213a 7.90
Fenofibrate
102.24 ꢁ 1.561a 71.23 ꢁ 1.678a 13.67 ꢁ 0.234a 51.68 ꢁ 0.978a 35.21 ꢁ 0.321a 2.90
1.46
2.62
4a
118.23 ꢁ 1.563a 89.12 ꢁ 1.543a 21.54 ꢁ 0.231a 65.85 ꢁ 1.432a 25.12 ꢁ 0.8322a 4.70
4b
112.78 ꢁ 1.853a 86.89 ꢁ 1.645a 19.86 ꢁ 0.121a 63.74 ꢁ 0.231a 24.78 ꢁ 0.2432a 4.55
2.57
4c
113.98 ꢁ 0.986a 84.98 ꢁ 1.235a 18.46 ꢁ 0.134a 64.73 ꢁ 0.837a 28.83 ꢁ 0.7822a 3.95
2.24
4d
114.36 ꢁ 0.882a 88.43 ꢁ 2.231a 22.83 ꢁ 0.285a 66.32 ꢁ 1.384 23.34 ꢁ 0.7349a 4.89
2.84
7a
113.28 ꢁ 1.213b 85.67 ꢁ 1.632a 18.35 ꢁ 0.345a 68.84 ꢁ 1.394a 29.12 ꢁ 0.6783c 3.89
2.36
7b
107.83 ꢁ 1.736a 83.56 ꢁ 1.674a 16.86 ꢁ 0.563a 59.85 ꢁ 2.129a 31.34 ꢁ 0.7839a 3.44
1.90
(continued on next page)

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H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Table 2 (continued )
Compound code
Compound
Parameter (mg/dl)
Atherogenic index LDL/HDL
TCH/HDL
TCH
TG
VLDL
LDL
HDL
7c
113.72 ꢁ 0.728b 86.23 ꢁ 1.523a 19.93 ꢁ 0.472a 62.83 ꢁ 1.098a 28.12 ꢁ 0.5648a 4.04
2.23
7d
101.56 ꢁ 1.483a 79.54 ꢁ 1.356a 14.73 ꢁ 0.365a 52.23 ꢁ 1.838a 33.78 ꢁ 0.5732a 3.00
1.54
7e
96.12 ꢁ 1.891a 76.89 ꢁ 1.457a 15.85 ꢁ 0.657a 49.94 ꢁ 2.243a 34.78 ꢁ 0.5428a 2.76
1.43
7f
107.87 ꢁ 0.643a 80.67 ꢁ 2.124a 16.34 ꢁ 0.345a 59.12 ꢁ 1.839a 29.93 ꢁ 0.6231a 3.60
1.97
7g
105.56 ꢁ 1.342a 82.56 ꢁ 1.674a 18.13 ꢁ 0.9678a 58.24 ꢁ 1.782a 31.54 ꢁ 0.1464a 3.34
1.84
7h
99.89 ꢁ 0.543a 80.45 ꢁ 1.853 15.43 ꢁ 0.232a 54.95 ꢁ 1.637a 33.57 ꢁ 0.6723a 2.97
1.63

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
127
Table 2 (continued )
Compound code
Compound
Parameter (mg/dl)
Atherogenic index LDL/HDL
TCH/HDL
TCH
TG
VLDL
LDL
HDL
7i
103.54 ꢁ 1.367a 83.43 ꢁ 1.673 16.85 ꢁ 0.466a 53.82 ꢁ 2.45a 32.85 ꢁ 0.1643a 3.15
1.63
Test compounds ¼ 250 mg/kg, reference standard, Fenofibrate ¼ 250 mg/kg, The results are expressed as mean ꢁ SEM, (n ¼ 6). The data is analyzed by using one-way analysis
of variance (ANOVA) followed by Turkey’s test.
a
p < 0.001.
p < 0.01.
Non significant.
b
c
(Chandigarh). Chemical shifts were measured relative to internal
standard TMS ( : 0). Chemical shifts are reported in scale (ppm).
6.91e7.85 (m, 12H, AreH), 6.07 (s, 2H, CH2, benzo-1,3-dioxole);
13C NMR (DMSO-d6)
ppm: 149.8, 148.3, 145.4, 121.5 (imidazo
d
d
d
Mass spectra of the synthesized compounds were recorded at MAT
120 in SAIF, Punjab University.
[2,1-b][1,3,4]thiadiazole) 153.4, 151.2, 129.5, 122.8, 117.6, 112.6,
102.8 [2-(1,3-benzodioxol-5-yl)] 150.6, 135.8, 127.6, 123.4, 113.8
(5-methylidene aniline) 138.6, 133.2, 131.2, 129.5 (6-phenyl);
HRMS (EI) m/z calcd for
502.0097.
C24H15BrN4O2S: 502.0099; found:
9.1. 5-(Benzo[d][1,3]dioxol-5-yl)-[1,3,4]thiadiazol-2-amine (1)
It is prepared as per the procedure given by G. Tu et al. [22].
9.3.3. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo[2,1-b]
[1,3,4]thiadiazol-5-yl) methylene)-4-methoxyaniline (4c)
IR (KBr) nmax 3042 (CH), 1672 (C]N), 1564 (C]C), 1178 (CeO)
9.2. 2-(Benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo[2,1-b][1,3,4]
thiadiazole (2) and 2(benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo
[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (3)
cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.64 (s, 1H, CH]N), 6.95e8.20
(m, 12H, AreH), 6.09 (s, 2H, CH2, benzo-1,3-dioxole), 3.90 (s, 1H,
OCH3); 13C NMR (DMSO-d6)
ppm: 150.5, 145.8, 145.2, 121.6 (imi-
d
It is prepared as per the procedure given by G. Kolavi et al. [23].
dazo[2,1-b][1,3,4]thiadiazole) 153.6, 151.6, 129.4, 127.4, 115.4, 110.8,
102.4 [2-(1,3-benzodioxol-5-yl)] 160.4, 148.4, 123.6, 116.4, 112.4 (5-
methylidene aniline) 138.2, 135.8, 131.6, 130.4 (6-phenyl) 56.4
(OCH3); HRMS (EI) m/z calcd for C25H18N4O3S: 454.1100; found:
454.1103.
9.3. General procedure for preparation of N-((2-(benzo[d][1,3]
dioxol-5-yl)-6-phenylimidazo[2,1-b][1,3,4]thiadiazol-5-yl)
methylene)-substituted anilines 4(aed)
Equimolar
quantities
of
2-(benzo[d][1,3]dioxol-5-yl)-6-
9.3.4. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo[2,1-b]
[1,3,4]thiadiazol-5-yl) methylene)-4-methylaniline (4d)
phenylimidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde 3 (0.01 M)
and substituted anilines (0.01 M) in 40 mL of ethanol was taken in
100 mL of round bottomed flask fitted with condenser. The mixture
was heated under reflux using water bath. When the solution is
mixed then added 1e2 drops of glacial acetic acid then reflux for
6 h, the reaction mixture was set aside for cooling. The solid deposit
was collected by filtration. The product was recrystallized from
ethanol.
IR (KBr) nmax 3011 (CH), 1652 (C]N), 1521 (C]C), 1265 (CeO)
cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.56 (s, 1H, CH]N), 6.92e7.88
(m, 12H, AreH), 6.04 (s, 2H, CH2, benzo-1,3-dioxole), 2.61 (s, 3H,
CH3); 13C NMR (DMSO-d6)
ppm: 150.4,146.6,138.4,121.4 (imidazo
d
[2,1-b][1,3,4]thiadiazole) 153.6, 151.2, 129.6, 123.1, 117.4, 112.0, 102.8
[2-(1,3-benzodioxol-5-yl)] 148.4, 145.6, 135.7, 127.6, 113.4 (5-
methylidene aniline) 138.1, 131.2, 131.0, 130.0 (6-phenyl) 24.8
(CH3); HRMS (EI) m/z calcd for C25H18N4O2S: 438.1150; found:
438.1153.
9.3.1. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo[2,1-b]
[1,3,4]thiadiazol-5-yl)methylene) aniline (4a)
IR (KBr) nmax 3067 (CH), 1648 (C]N), 1582 (C]C), 1282 (CeO)
9.4. Synthesis of 2-(benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imi-
dazo[2,1-b][1,3,4]thiadiazole (5) and 2-(benzo[d][1,3]dioxol-5-yl)-6-
(4-chlorophenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (6)
cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.56 (s, 1H, CH]N), 6.89e7.89
(m, 13H, AreH), 6.01 (s, 2H, CH2, benzo-1,3-dioxole); 13C NMR
(DMSO-d6) ppm: 150.2, 148.6, 145.8, 121.4 (imidazo[2,1-b][1,3,4]
d
thiadiazole) 153.1, 151.6, 128.8, 123.8, 115.2, 112.5, 102.6 [2-(1,3-
benzodioxol-5-yl)] 153.9, 131.2, 129.3, 127.2, 113.5 (5-methylidene
aniline) 138.6, 135.8, 131.0, 130.6 (6-phenyl); HRMS (EI) m/z calcd
for C24H16N4O2S: 424.0994; found: 424.0997.
It is prepared as per the procedure given by G. Kolavi et al. [27].
9.5. General procedure for preparation N-((2-(benzo[d][1,3]dioxol-
5-yl)-6-(4-chlorophenyl)imidazo[2,1-b][1,3,4]thiadiazol-5-yl)methy-
lene)substituted aniline 7(aei)
9.3.2. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-phenylimidazo[2,1-b]
[1,3,4]thiadiazol-5-yl) methylene)-4-bromoaniline (4b)
IR (KBr) nmax 3050 (CH), 1652 (C]N), 1506 (C]C), 1278 (CeO),
Equimolar quantities of 2-(benzo[d][1,3]dioxol-5-yl)-6-(4-
634 (CeBr) cmꢃ1; 1H NMR (DMSO-d6)
d
ppm: 8.48 (s, 1H, CH]N),
chlorophenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde
6

128
H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Table 3
Effect of synthesized compounds 7d, 7e, 7g, 7h and 7i on liver marker enzyme.
Compound code
Compound
Alanine transferase (SGPT) IU
Aspartate transferase (SGOT) IU
Alkaline phosphatase KA unit
Normal range
Normal control
Hyperlipidemic control
Fenofibrate treated
18e30
46e81
14e32
24.2 ꢁ 1.0a
42.32 ꢁ 0.54
26.43 ꢁ 1.21a
48.4 ꢁ 2.1a
85.84 ꢁ 1.12
49.45 ꢁ 1.34a
28.8 ꢁ 1.5a
41.64 ꢁ 1.65
28.33 ꢁ 0.43a
Compound 7d
28.6 ꢁ 0.5a
51.7 ꢁ 1.5a
29.3 ꢁ 0.3a
Compound 7e
26.8 ꢁ 0.5a
48.3 ꢁ 1.8a
29.5 ꢁ 0.5a
Compound 7g
28.3 ꢁ 1.0a
49.9 ꢁ 2.3a
28.8 ꢁ 1.2a
Compound 7h
27.8 ꢁ 1.0a
56.5 ꢁ 2.1a
27.3 ꢁ 1.0a
Compound 7i
29.3 ꢁ 0.5a
58.8 ꢁ 1.2a
26.6 ꢁ 0.5a
The results are expressed as mean ꢁ SEM, (n ¼ 6). The data is analyzed by using one-way analysis of variance (ANOVA) followed by Turkey’s test.
a
p < 0.001.
(0.01 M) and substituted amines (0.01 M) in 40 mL of ethanol was
taken in 100 mL of round bottomed flask fitted with condenser. The
mixture was heated under reflux using water bath. When the so-
lution is mixed then added 1e2 drops of glacial acetic acid then
reflux for 6 h, the reaction mixture was set aside for cooling. The
solid deposit was collected by filtration. The product was recrys-
tallized from ethanol.
9.5.1. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-4-methylaniline (7a)
IR (KBr) nmax 3026 (CH),1645 (C]N),1556 (C]C),1261 (CeO), 710
(CeCl) cmꢃ1; 1H NMR (DMSO-d6)
d
ppm: 8.56 (s, 1H, CH]N), 6.98e
7.88 (m, 11H, AreH), 6.16 (s, 2H, CH2, benzo-1,3-dioxole), 2.62 (s, 3H,
CH3); 13C NMR (DMSO-d6)
ppm: 150.4, 145.6, 136.4, 122.4 (imidazo
[2,1-b][1,3,4]thiadiazole) 153.2, 151.4, 129.4, 124.6, 118.5 [2-(1,3-
d

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
129
Fig. 2. Hepatocytes of rats stained with hematoxylin and eosin (100ꢀ magnification); a) control group showing normal architecture; b) hyperlipidemic group showing fatty
infiltration and granular degeneration; c) Fenofibrate group showing negligible cytoplasmic fatty infiltration and granular degeneration; d) compound 7d, 7e and 7h treated group
showing mild cytoplasmic fatty infiltration and mild granular degeneration; e) compound 7g and 7i treated group showing mild cytoplasmic fatty infiltration and mild to moderate
granular degeneration.
benzodioxol-5-yl)] 148.4, 144.8, 131.5, 128.6, 114.2 (5-methylidene
aniline) 135.8, 134.5, 132.8, 130.8 (6-phenyl) 24.3 (CH3); HRMS (EI)
m/z calcd for C25H17ClN4O2S: 472.0761; found: 472.0763.
6.94e7.79 (m, 11H, AreH), 6.10 (s, 2H, CH2, benzo-1,3-dioxole), 2.64
(s, 3H, CH3); 13C NMR (DMSO-d6)
ppm: 150.1, 148.6, 141.4, 116.2
d
(imidazo[2,1-b][1,3,4]thiadiazole) 153.4, 150.3, 129.9, 122.6, 114.2,
110.3, 102.4 [2-(1,3-benzodioxol-5-yl)] 151.8, 145.2, 132.6, 126.6,
124.6, 120.6, 112.4 (5-methylidene aniline) 136.2, 135.2, 133.6, 130.4
(6-phenyl) 24.6 (CH3); HRMS (EI) m/z calcd for C25H17ClN4O2S:
472.0761; found: 472.0764.
9.5.2. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-3-methoxyaniline (7b)
IR (KBr) nmax 3078 (CH), 1656 (C]N), 1511 (C]C), 1249 (CeO),
721 (CeCl) cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.35 (s, 1H, CH]N),
7.02e7.91 (m, 11H, AreH), 6.19 (s, 2H, CH2, benzo-1,3-dioxole), 3.91
(s, 3H, OCH3); 13C NMR (DMSO-d6)
ppm: 150.2, 148.8, 145.4, 122.3
9.5.4. 4-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methyleneamino)benzenesulfonamide
(7d)
d
(imidazo[2,1-b][1,3,4]thiadiazole) 152.5, 151.6, 128.6, 127.5, 116.3,
112.4, 102.4 [2-(1,3-benzodioxol-5-yl)] 164.6, 153.6, 131.6, 118.2,
114.2, 110.6, 108.6 (5-methylidene aniline) 136.6, 135.4, 132.6, 130.2
(6-phenyl) 56.2 (OCH3); HRMS (EI) m/z calcd for C25H17ClN4O3S:
488.0710; found: 488.0713.
IR (KBr) nmax 3448 (NH), 3011 (CH), 1676 (C]N), 1581 (C]C),
1248 (CeO), 661 (CeCl) cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.32 (s,
1H, CH]N), 6.89e7.92 (m, 11H, AreH), 6.09 (s, 2H, CH2, benzo-1,3-
dioxole), 4.01 (s, 2H, NH2) 13C NMR (DMSO-d6)
ppm: 150.6, 146.3,
d
143.4, 124.4 (imidazo[2,1-b][1,3,4]thiadiazole) 152.9, 151.6, 127.4,
122.4, 114.6, 111.2, 106.3 [2-(1,3-benzodioxol-5-yl)] 153.2, 145.3,
130.4, 128.4, 116.2 (5-methylidene aniline) 136.2, 135.6, 133.4, 132.4
(6-phenyl); HRMS (EI) m/z calcd for C24H16ClN5O4S2: 537.0332;
found: 537.0335.
9.5.3. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-3-methylaniline (7c)
IR (KBr) nmax 3062 (CH), 1634 (C]N), 1580 (C]C), 1261 (Ce
O),715 (CeCl) cmꢃ1; 1H NMR (DMSO-d6)
d ppm: 8.75 (s,1H, CH]N),

130
H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Table 4
Glide docking results based on hydrogen bonding interaction, glide dock score and E-model.
Compound Code
Compound
H-bond interaction
Glide score (kcal/mol)
E-model
Compound 4a
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ4.84
ꢃ76.67
Compound 4b
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ5.34
ꢃ80.45
Compound 4c
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ6.88
ꢃ83.34
Compound 4d
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ4.48
ꢃ74.74
Compound 7a
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ4.68
ꢃ75.21
Compound 7b
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ5.88
ꢃ79.43

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
131
Table 4 (continued )
Compound Code
Compound
H-bond interaction
Glide score (kcal/mol)
E-model
Compound 7c
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ4.34
ꢃ73.74
Compound 7d
Oxygen of sulphonamido group and H
atom of amino acid backbone of HIE-298 and SER-336
ꢃ9.24
ꢃ96.56
Compound 7e
Oxygen of carboxyl group and H atom
of amino acid backbone of HIE-298 and SER-336
ꢃ9.89
ꢃ98.88
Compound 7f
Oxygen of amide group and H atom of
amino acid backbone of HIE-298 and SER-336
ꢃ8.32
ꢃ82.82
Compound 7g
Oxygen of nitro group and H atom of amino
acid backbone of HIE-298 and SER-336
ꢃ8.21
ꢃ84.99
Compound 7h
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ8.01
ꢃ81.24
(continued on next page)

132
H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
Table 4 (continued )
Compound Code
Compound
H-bond interaction
Glide score (kcal/mol)
E-model
Compound 7i
N-6 of imidazo[2,1-b][1,3,4]thiadiazoles
and H atom of amino acid backbone of HIE-298
ꢃ6.78
ꢃ80.82
9.5.5. 4-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methyleneamino)benzoic acid (7e)
IR (KBr) nmax 3450 (OH), 3009 (CH), 1672 (C]N), 1584 (C]C),
methylidene aniline) 136.6, 133.6, 132.6, 130.6 (6-phenyl); HRMS
(EI) m/z calcd for C25H16ClN5O3S: 501.0662; found: 501.0662.
1259 (CeO), 708 (CeCl) cmꢃ1; 1H NMR (DMSO-d6)
d
ppm: 10.56 (s,
1H, COOH), 8.62 (s, 1H, CH]N), 6.90e8.03 (m, 11H, AreH), 6.14 (s,
2H, CH2, benzo-1,3-dioxole),; 13C NMR (DMSO-d6)
ppm: 150.2,
9.5.7. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-4-nitroaniline (7g)
IR (KBr) nmax 3061 (CH), 1678 (C]N), 1581 (C]C), 1551, 1342
d
148.4, 144.6, 122.8 (imidazo[2,1-b][1,3,4]thiadiazole) 153.2, 151.5,
129.4, 124.5, 124.5, 116.8, 110.8, 102.4 [2-(1,3-benzodioxol-5-yl)]
170.1, 155.6, 132.6, 129.6, 127.8, 112.6 (5-methylidene aniline) 136.8,
135.7, 133.7, 130.2 (6-phenyl); HRMS (EI) m/z calcd for
(NO2), 1249 (CeO), 705 (CeCl) cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm:
8.62 (s, 1H, CH]N), 7.01e8.12 (m, 11H, AreH), 6.11 (s, 2H, CH2,
benzo-1,3-dioxole); 13C NMR (DMSO-d6)
ppm: 148.4, 147.2, 145.4,
d
122.4 (imidazo[2,1-b][1,3,4]thiadiazole) 153.6, 151.8, 130.2, 124.5,
116.2, 112.4, 102.4 [2-(1,3-benzodioxol-5-yl)] 158.4, 150.4, 128.6,
126.6, 114.2 (5-methylidene aniline) 136.1, 135.6, 133.4, 132.4 (6-
phenyl); HRMS (EI) m/z calcd for C24H14ClN5O4S: 503.0455;
found: 503.0458.
C
25H15ClN4O4S: 502.0503; found: 502.0505.
9.5.6. N0-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)benzohydrazide (7f)
IR (KBr) nmax 3448 (NH), 3031 (CH), 1656 (C]O),1671 (C]N),
1515 (C]C), 1271 (CeO),689 (CeCl) cmꢃ1
;
1H NMR (DMSO-d6)
9.5.8. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-3-chloro-4-fluoroaniline
(7h)
d
ppm: 8.79 (s, 1H, CH]N), 6.93e8.04 (13H, Complex containing
AreH and NH), 6.12 (s, 2H, CH2, benzo-1,3-dioxole); 13C NMR
(DMSO-d6) ppm: 148.9, 145.6, 141.3, 116.4 (imidazo[2,1-b][1,3,4]
d
IR (KBr) nmax 3018 (CH), 1659 (C]N), 1535 (C]C), 1254 (CeO),
thiadiazole) 151.2, 150.4, 127.6, 122.4, 114.6, 112.4, 102.4 [2-(1,3-
benzodioxol-5-yl)] 165.4, 135.5, 133.2, 129.3, 128.4, 110.3 (5-
1084 (CeF), 721 (CeCl) cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.71 (s,
1H, CH]N), 6.99e8.04 (m, 10H, AreH), 6.15 (s, 2H, CH2, benzo-1,3-
Fig. 3. Binding mode of 7d, 7e and co-crystallized ligand Fexaramine in the FXR binding pocket (PDB: 1OSH). Compound 7d shows H-bond interaction between oxygen of sul-
phonamido group and compound 7e shows H-bond interaction between oxygen of carboxyl group with Histidine-298 and Serine-336 amino acid backbone of FXR (Figure A and B),
similarly Co-crystallized ligand Fexaramine shows H-bond interaction between oxygen of carboxamide group with Hiestedine-298 backbone of FXR (Figure C).

H.M. Patel et al. / European Journal of Medicinal Chemistry 65 (2013) 119e133
133
dioxole); 13C NMR (DMSO-d6)
d ppm: 149.4, 148.4, 145.8, 116.8
[11] Y. Song, D.T. Connor, A.D. Sercel, R.J. Soreson, R. Doubleday, P.C. Unangst,
B.D. Roth, V.G. Beylin, R.B. Gilbersten, K. Chan, D.J. Schrier, A. Guglietta,
D.A. Bornemeier, R.D. Dyer, J. Med. Chem. 42 (1999) 1161e1169.
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I.F. Terlloch, D.S. Walter, A.P. Welbourn, J. Med. Chem. 42 (1986) 2273e2280.
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J. Med. Chem. 31 (1988) 7e11.
(imidazo[2,1-b][1,3,4]thiadiazole) 152.6, 151.6, 130.6, 120.6, 112.3,
111,101.2 [2-(1,3-benzodioxol-5-yl)] 159.4,156.4,127.8,124.8,122.6,
118.4, 112.6 (5-methylidene aniline) 136.6, 135.6, 133.6, 132.8 (6-
phenyl); HRMS (EI) m/z calcd for C24H13Cl2FN4O2S: 510.0120;
found: 510.0123.
[14] S. Turner, M. Myers, B. Gadie, A.J. Nelson, R. Pape, J.F. Saville, J.C. Doxey,
T.L. Berridge, J. Med. Chem. 31 (1988) 902e906.
[15] S. Turner, M. Myers, B. Gadie, S.A. Hale, A. Horsley, A.J. Nelson, R. Pape,
J.F. Saville, J.C. Doxey, T.L. Berridge, J. Med. Chem. 31 (1988) 907e915.
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(2008) 276e283.
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9.5.9. N-((2-(Benzo[d][1,3]dioxol-5-yl)-6-(4-chlorophenyl)imidazo
[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-4-bromoaniline (7i)
IR (KBr) nmax 3034 (CH), 1671 (C]N), 1551 (C]C), 1249 (CeO),
705 (CeCl), 651 (CeBr) cmꢃ1
;
1H NMR (DMSO-d6)
d
ppm: 8.74 (s,
1H, CH]N), 6.91e7.95 (m, 11H, AreH), 6.12 (s, 2H, CH2, benzo-1,3-
dioxole); 13C NMR (DMSO-d6)
ppm: 148.8, 148.1, 145.6, 121.8
d
(imidazo[2,1-b][1,3,4]thiadiazole) 153.4, 151.6, 130.6, 122.7, 116.8,
111.3, 102.8 [2-(1,3-benzodioxol-5-yl)] 150.6, 135.8, 128.8, 124.6,
114.8 (5-methylidene aniline) 136.2, 133.6, 132.6, 131.8 (6-phenyl);
HRMS (EI) m/z calcd for C24H14BrClN4O2S: 535.9709; found:
535.9711.
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3080.
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York, 1997, pp. 43e86.
Acknowledgment
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The authors would like to thank Director General, Department
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(Grant No. SR/FT/LS-0024/2008).
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