Imidazole-pyrazole hybrids: Synthesis, characterization and in-vitro bioevaluation against α-glucosidase enzyme with molecular docking studies

Article abstract of DOI:10.1016/j.bioorg.2018.10.047

Herein, substituted imidazole-pyrazole hybrids (2a-2n) were prepared via a multi component reaction employing pyrazole-4-carbaldehydes (1a-1d), ammonium acetate, benzil and arylamines as reactants. All the new compounds were characterized through their spectral and elemental analyses. Further these compounds were tested against α-glucosidase enzyme. The compounds 2k, 2l and 2n possessed good inhibition potencies, however, compounds 2f (IC₅₀ value: 25.19 ± 0.004 μM) and 2m (IC₅₀ value: 33.62 ± 0.03 μM) were the most effective compounds of the series. Furthermore, molecular docking helped to understand the binding interactions of 2f and 2m with the understudy yeast's α-glucosidase enzyme.

Full text of DOI:10.1016/j.bioorg.2018.10.047

Accepted Manuscript
Imidazole-Pyrazole Hybrids: Synthesis, characterization and in-vitro bioevalu-
ation against α-glucosidase enzyme with molecular docking studies
Faryal Chaudhry, Sadia Naureen, Muhammad Ashraf, Mariya al-Rashida,
Bakhat Jahan, Munawar Ali Munawar, Misbahul Ain Khan
PII:
S0045-2068(18)30679-5
DOI:
https://doi.org/10.1016/j.bioorg.2018.10.047
YBIOO 2581
Reference:
To appear in:
Bioorganic Chemistry
Please cite this article as: F. Chaudhry, S. Naureen, M. Ashraf, M. al-Rashida, B. Jahan, M. Ali Munawar, M. Ain
Khan, Imidazole-Pyrazole Hybrids: Synthesis, characterization and in-vitro bioevaluation against α-glucosidase
enzyme with molecular docking studies, Bioorganic Chemistry (2018), doi: https://doi.org/10.1016/j.bioorg.
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018.10.047
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Title
Imidazole-Pyrazole Hybrids: Synthesis, characterization and in-vitro bioevaluation against α-
glucosidase enzyme with molecular docking studies
Authors
Faryal Chaudhry a, b , Sadia Naureen , Muhammad Ashraf , Mariya al-Rashida , Bakhat Jahan
a
c
d
c, Munawar Ali Munawar a, , Misbahul Ain Khan a, c
Affiliations
aInstitute of Chemistry,University of the Punjab, Lahore 54590, Pakistan
bDepartment of Chemistry, Kinnaird College for Women, Lahore 54000, Pakistan
cDepartment of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan
dDepartment of Chemistry, Forman Christian College (A Chartered University), Ferozepur
Road, Lahore 54600, Pakistan
*
Corresponding Author
Dr. Faryal Chaudhry, E-mail: faryal.chaudhry@kinnaird.edu.pk; frylchaudhry@yahoo.com
Dr. Munawar Ali Munawar, E-mail: mamunawar.chem@pu.edu.pk

Graphical Abstract
R2
N
N
N
N
Glucosidase
inhibition studies
R1
Imidazolylpyrazoles (2a-2n)
Compound 2e
Inhibition (%): 96.21±0.11 ; IC50 (M): 25.19±0.004

Imidazole-Pyrazole Hybrids: Synthesis, characterization and in-vitro
bioevaluation against α-glucosidase enzyme with molecular docking studies
Faryal Chaudhry a, b , Sadia Naureen , Muhammad Ashraf , Mariya al-Rashida , Bakhat Jahan
a
c
d
c, Munawar Ali Munawar a, , Misbahul Ain Khan a, c
aInstitute of Chemistry,University of the Punjab, Lahore 54590, Pakistan
bDepartment of Chemistry, Kinnaird College for Women, Lahore 54000, Pakistan
cDepartment of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan
dDepartment of Chemistry, Forman Christian College (A Chartered University), Ferozepur
Road, Lahore 54600, Pakistan
Abstract
Herein, substituted imidazole-pyrazole hybrids (2a-2n) were prepared via a multi component
reaction employing pyrazole-4-carbaldehydes (1a-1d), ammonium acetate, benzil and arylamines
as reactants. All the new compounds were characterized through their spectral and elemental
analyses. Further these compounds were tested against α-glucosidase enzyme. The compounds 2k,
2
l and 2n possessed good inhibition potencies, however, compounds 2f (IC value: 25.19±0.004
50
μM) and 2m (IC value: 33.62±0.03 μM) were the most effective compounds of the series.
5
0
Furthermore, molecular docking helped to understand the binding interactions of 2f and 2m with
the understudy yeast’s α-glucosidase enzyme.
Keywords:
Multicomponent reactions; α-Glucosidase inhibitors; Tetrasubstituted Imidazoles; Molecular
modeling
*
Corresponding Author
Dr. Faryal Chaudhry, E-mail: faryal.chaudhry@kinnaird.edu.pk; frylchaudhry@yahoo.com
Dr. Munawar Ali Munawar, E-mail: mamunawar.chem@pu.edu.pk

1
.
Introduction
Imidazole, a fundamental class of heterocycles, is a unique template of multifaceted applications.
This nitrogen containing molecule is not only a natural motif (element of DNA base, histidine,
alkaloids, biotin, vitamin B12 etc.) but also documented as plant growth regulators and pesticides
in agriculture [1-3]. They are widely used in catalysis, analytical and organometallic chemistry, as
dyes and fluorescent molecules in optical industries, in solar cells and organic light emitting diodes
and also employed for various other purposes [4-6]. Different imidazole based clinical drugs have
also broadened the therapeutic scope of this scaffold. Therefore, medicinal candidature of
imidazole as various enzymes inhibitors [7-10], antimicrobial [11-13], antiviral [14],
antitubercular [15,16], antitumor [17], anticancer [18], anti-inflammatory [19], antiepileptic [20]
and antiplatelet [21] drugs etc. is an exceptional one (Fig. 1).
O
CH3
N
CH3
N
O
O
N N
S
OH
N
NH2
NO2
H N
2
NH2
HN
N
N
Histidine (Amino acid)
Preclathridine A (Alkaloid)
Megazol (Antiparasitic)
Cl
N
N
N
N
OH
Nafimidone (Antineuropathic)
Clotrimazole (Antifungl)
Figure 1. Biologically important imidazole-based compounds.
Various studies have shown that diabetes mellitus is an emerging threat to human health which
might lead to death. Recent evidences have supported the existence of relationship between α-
glucosidase enzyme and type 2 diabetes mellitus. To deal with this disease, inhibition of α-
glucosidase enzyme’s functioning can help in controlling blood sugar [22-24]. Literature reveals
that imidazole-pyrazole hybrids containing molecules could also function as potent inhibitors of
targeted enzyme [25]. These observations have encouraged us to continue our previous research,
where diazoles linked with other heterocyles proved as effective inhibiting agents [26-28]. Herein,
we would like to share some new discoveries. The purpose of present study was to evaluate
synthesized compounds against α-glucosidase enzyme to examine whether these compounds have
better targeting potentials or not. To the best of our knowledge, such tetrasubstituted imidazoles
(2a-2n) were not yet tested against α-glucosidase (Fig. 2).

R
H
N
R2
N
N
N
NH
N
N
R1
R'
Previous Work
Imidazolylindoles
Current Target
Imidazolylpyrazoles
(-glucosidase inhibitors)
(-glucosidase inhibition potencies ?)
Figure 2. Designing of potent imidazole-pyrazole hybrids.
2
2
.
Results and Discussion
Chemistry
.1.
To synthesize designed imidazolylpyrazole scaffolds, synthetic route of Scheme 1 was employed.
Initially, different substituted pyrazole-4-carbaldehydes were prepared [29]. A versatile MCR
Debus-Radziszewski reaction was utilized to construct an imidazole nucleus over a pyrazole
moiety. This reaction has involved microwave irradiation of a mixture of four components: a
pyrazole-4-carbaldehyde, substituted aniline, benzil and ammonium acetate. The acetic acid was
used as a solvent. The present reaction is fairly compatible with various aldehydes having different
electron donating / withdrawing groups (1a-1d). In this way, some functionally diversified
compounds (2a-2n) were prepared.
The elemental composition and structural identification of novel derivatives (2a-2n) were carried
1
out by different spectroscopic means. As expected, the H NMR spectra of highly arylated
imidazolylpyrazoles showed a complex pattern of signals in aromatic region. Somewhere beautiful
splitting pattern of aromatic protons with appropriate J values were also detected. In all
compounds, H-5 of pyrazole was easily distinguished in the region of 8.10-8.45 ppm as a singlet
and supported the proposed structure. The characteristic signals of linking carbons: C-4 of pyrazole
1
3
and C-2 of imidazole were found around 112.00 ppm and 140.00 ppm respectively in C NMR
spectra which has confirmed the development of new C-C bond between two hetaryl rings. All
mass spectra have distinct molecular ion peaks due to the stability of compounds. The IR data and
elemental analyses were also in support of suggested structural patterns.

O
CH3
O
PhNHNH2
Ethanol
H
POCl3
N
H
R1
H C
3
R1
N
DMF
N

N
R1
0
-5 C
Acetophenones
Phenyl hydrazones
Pyrazole-3-carbaldehydes 1(a-d)
O
R1
N
N
H
R2
N
Benzil, NH OAc,
4
N
N
R1
2
Substituted Aniline (R NH ),
N
2
AcOH, MW
2
(a-n)
2h. R = p-BrC H , R = p-OCH C H
3 6 4
1
(a-d)
2
1
2
2
2
2
2
2
2
2
a. R1 = p-OCH C H , R = p-OCH C H
3
6
4
3
6
4
6
4
1
2
1
2
b. R = p-OCH C H , R = p-BrC H
2i. R = p-BrC H , R = p-ClC H
6 4 6 4
a. R1 = p-OCH C H
3
6
4
6
4
1
1
1
1
3
6
4
c. R1 = p-OCH C H , R = 3,5-(CH ) C H 2j. R = p-BrC H , R = 3,5-(CH ) C H
2
1
2
1
3
6
4
2
3 2
6
3
6
4
3 2
6
3
b. R = p-ClC H4
6
1
1
2
d. R = p-ClC H , R = p-OCH C H
e. R = p-ClC H , R = p-ClC H
f. R = p-ClC H , R = p-BrC H
g. R1 = p-ClC H , R = 3,5-(CH ) C H
2k. R = m-NO C H , R = p-ClC H
2 6 4 6 4
2l. R = m-NO C H , R = p-OCH C H
2 6 4 3 6 4
2m. R = m-NO C H , R = p-BrC H
2 6 4 6 4
2n. R = m-NO C H , R = 3,5-(CH ) C H
2 6 4 3 2 6 3
c. R1 = p-BrC H4
6
4
3
6
4
6
1
2
1
2
1
6
4
6
4
d. R = m-NO C H
2
6
4
1
2
1
2
6
4
6
4
2
1
2
6
4
3 2
6
3
Scheme 1. General scheme of the synthesis of compounds 2a-2n.
2
.2.
α-Glucosidase enzyme inhibition
These newly prepared imidazolylpyrazoles (2a-2n) were evaluated for their in vitro α-glucosidase
inhibition using acarbose as standard reference (Table 1). In terms of percentage inhibition, all
1
2
compounds have shown good results. There were visible influences of R and R substitutions on
inhibition potencies of prepared compounds.
As evident from literature [25-28], here also, the introduction of electron donating substitutions
due to electron withdrawing substitutions resulted in significant decrease in inhibition strength.
The p-OCH C H group containing derivatives 2a (IC (µM): 178.82±0.28), 2b (IC (µM):
3
6
4
50
50
1
62.93±0.32) and 2c (IC (µM): 182.17±0.37) have weak to moderate binding capabilities but the
50
replacement of this methoxy group with other functionalities helped in recovering the inhibition
potentials. The p-ClC H substituted compounds 2d (IC (µM): 168.92±0.27), 2e (IC (µM):
6
4
50
50
8
5.71±0.09) and 2g (IC (µM): 132.81±0.29) have improved inhibitory effects. However, the
50
product 2f was proved to be the most significant agent (Inhibition (%): 96.21±0.11, IC (µM):
5
0
2
5.19±0.004). Probably, the synergistic effects of chloro and bromo substituents in one molecule

augment the active nature of compound which can also be observed in case of compound 2i (IC50
µM): 84.61±0.01). The compounds 2h and 2j, where only p-BrC H functionality was present as
(
6
4
1
R , have executed moderate inhibitory effects. The electron withdrawing group containing
molecules have shown excellent results and served as potent scaffolds. Therefore, switching to the
1
m-NO C H group (as R in compounds 2k-2n) has contributed in regaining the enhanced binding
2
6
4
affinities of molecules with enzyme’s active sites. Out of these examples, compound 2m has
displayed even better activity than that of positive control acarbose with inhibition (%):
9
7.52±0.26, IC (µM): 33.62±0.03.
50
Table 1. α-Glucosidase inhibition results of imidazolylpyrazoles (2a-2n).
R1
N
N
N
N
R2
(2a-2n)
Sr. Compd.
Substitutions
Substitutions
Percentage IC (µM)
Inhibition (%) at
.5 mM
R1
R1
No.
No.
5
0
0
1
2
3
4
5
6
7
8
2a
2b
2c
2d
2e
2f
p-OCH C H
p-OCH C H
4
99.56 ± 0.77
91.12 ± 0.84
96.13 ± 0.89
98.65 ± 0.79
93.19 ± 0.52
96.21 ± 0.11
89.54 ± 0.86
89.76 ± 0.19
178.82 ± 0.28
162.93 ± 0.32
182.17 ± 0.37
168.92 ± 0.27
85.71 ± 0.09
25.19 ± 0.004
132.81 ± 0.29
104.75 ± 0.06
3
6
4
4
4
3
6
p-OCH C H
p-BrC H
6 4
3
6
p-OCH C H
3,5-(CH ) C H
3 2 6 3
3
6
p-ClC H
p-OCH C H
3 6 4
6
4
4
4
4
p-ClC H
p-ClC H
6 4
6
p-ClC H
p-BrC H
6 4
6
2g
2h
p-ClC H
3,5-(CH ) C H
3 2 6 3
6
p-BrC H
p-OCH C H
3 6 4
6
4

9
2i
2j
p-BrC H
p-ClC H
4
87.25 ± 0.21
75.23 ± 1.74
96.76 ± 0.38
95.79 ± 0.32
97.52 ± 0.26
91.25 ± 0.54
92.23 ± 0.14
84.61 ± 0.01
412.42 ± 1.15
42.23 ± 0.07
43.14 ± 0.05
33.62 ± 0.03
58.73 ± 0.13
38.25 ± 0.12
6
4
4
6
1
0
1
2
3
4
p-BrC H
3,5-(CH ) C H
3 2 6 3
6
1
1
1
1
2k
2l
m-NO C H
p-ClC H
2
6
4
4
4
4
6
4
m-NO C H
p-OCH C H
3 6 4
2
6
2m
2n
m-NO C H
p-BrC H
6 4
2
6
m-NO C H
3,5-(CH ) C H
3 2 6 3
2
6
Acarbose
2
.3.
Molecular docking studies
The docking studies were carried out for analyzing the probable inhibitory action of the leading α-
glucosidase inhibitors 2f and 2m of the series. The crystal structure α-glucosidase from
Saccharomyces cerevisiae is not yet available from the Protein Data Bank (PDB), therefore in
order to carry out molecular docking studies its homology model was built and validated.
Fig. 3 shows 3D and 2D interactions of most probable docked conformation of compound 2f. The
inhibitor 2f was found to have a snug fit inside the binding cavity. A hydrogen bonded interaction
(1.74 Å) was observed between the unsubstituted nitrogen atom of pyrazole ring and amino acid
Asn241. The binding energy was calculated to be -21 kJ/mol. Molecular docking studies of second
most active inhibitor 2m were also carried out, the results are presented in Fig. 4. The compound
2
m was found to have a similar binding mode as that of 2f, the unsubstituted nitrogen atom of the
pyrazole ring was making a hydrogen bond with Asn241 (1.36 Å). Moreover, the oxygen atoms
of the nitro group were acting as hydrogen bond acceptor towards amino acid Arg312. The
calculated binding energy was -19 kJ/mol.

Figure 3. Most probable docked conformation of most potent inhibitor 2f.
Figure 4. Possible docked conformation of inhibitor 2m.
To further gain insight into the structural elements, responsible for the observed inhibitory effect
against the enzyme, the most active inhibitor 2f bound to protein was subjected to binding affinity
evaluation using Hyde utility of LeadIT Software. Hyde allows visual approximation of favorable
and unfavorable contributions due to the structure / bound conformation of inhibitor with the
surrounding amino acids. The structural elements (atoms and torsions) that are contributing

favorably to the overall binding energy are visually coloured in green, similarly the structural
elements that are not contributing favorably are coloured in red, and neutral elements are in white.
As can be seen from Fig. 5, overall the aromatic phenyl rings substituted on pyrazole and imidazole
rings are contributing favorably to the binding energy. The only unfavorable structural element
was the un-substituted nitrogen atom of the imidazole ring, this lead to the speculation that if this
nitrogen atom is replaced by some other atoms such as carbon or other heteroatom, it may lead to
even better binding affinity and therefore inhibition against α-glucosidase.
Figure 5. Hyde affinity analysis of most active inhibitor 2f.
3
. Conclusion
The present research is about initial efforts to synthesize novel tetrasubstituted
imidazolylpyrazoles in good yields which could also be valuable as α-glucosidase inhibitors.
Therefore, these compounds were first evaluated for their inhibitory potentials against yeast’s α-
glucosidase enzyme. Most of these molecules have displayed moderate to excellent results.
However, on the basis of SAR studies and molecular docking, 2f (IC value: 25.19±0.004 μM)
5
0
and 2m (IC value: 33.62±0.03 μM) were identified to be promising α-glucosidase inhibitors.
50

4
4
. Experimental
.1.
General methods
The chemicals were used as purchased from the manufacturers (Merck, Sigma-Aldrich and Acros).
The melting points (uncorrected) were taken on Gallen Kamp. The Agilent Technologies Cary 630
1
13
FTIR was employed for FTIR spectra. The H ( C) NMR spectra, in CDCl /DMSO-d , were
3
6
recorded on Bruker DPX Instruments of 500 (126) or 700 (175) MHz. TMS was used as standard
and J-values are calculated in Hz. The MS were recorded on GC MS DFS-Thermo. The elemental
percentages (CHN) were determined on Perkin Elmer 2400 Series II CHN/S Analyzer.
4
.2. General protocol for the synthesis of imidazolylpyrazoles (2a-2n)
An equimolar mixture of pyrazole-4-carbaldehyde (1a-1d), benzil, ammonium acetate and
substituted aniline in acetic acid was irradiated under microwave. The reaction completion was
observed by TLC. The mixture was poured over crushed ice, crude product was separated and
further recrystallized with ethanol to get pure product (2a-2n).
In this way, following compounds (2a-2n) were synthesized:
4
.2.1. 3-(4-Methoxyphenyl)-4-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-
phenyl-1H-pyrazole (2a)
From p-anisidine (0.27 g) and 1a (0.56 g), 2a was obtained as a white solid; m.p. 180 ºC; Yield:
-1
0
.77 g; 75%; IR (νmax-cm ; neat): 3102-2839 (C-H), 1602 (C=N), 1594 (C=C), 1252 & 1022 (Ar-
1
O-CH ); H NMR (CDCl , 500 MHz), δ: 3.66 (s, 3H; -OCH ), 3.80 (s, 3H; -OCH ), 6.44 (d, 2H, J
3
3
3
3
3
3
2
=
9.0 Hz; Ar -2H), 6.50 (d, 2H, J = 9.0 Hz; Ar -2H), 6.80 (d, 2H, J = 8.8 Hz; Ar -2H), 7.13 (dd,
4
4
5
1
2
H, J = 7.5, 1.9 Hz; Ar -2H), 7.20-7.24 (m, 4H; Ar -3H & Ar -1H), 7.26-7.30 (m, 3H; Ar -1H &
5
2
1
Ar -2H ), 7.37 (d, 2H, J = 8.8 Hz; Ar -2H), 7.45 (t, 2H, J = 8.0 Hz; Ar -2H), 7.65 (d, 2H, J = 7.3
5
1
13
Hz; Ar -2H), 7.72 (d, 2H, J = 8.0 Hz; Ar -2H), 8.19 (s, 1H; H-5 Pyrazole); C NMR (CDCl , 126
3
MHz), δ: 55.37 (-OCH ), 55.42 (-OCH ), 111.94 (C-4 Pyrazole), 113.52, 113.73, 119.00, 125.73,
3
3
1
1
26.65, 126.73, 127.38, 128.04, 128.30, 128.50, 128.85, 128.86, 129.07, 129.38 (CH-5 Pyrazole),
29.56, 130.58 (C-4 Im), 130.76, 131.06, 134.47, 137.85 (C-5 Im), 139.82, 140.94 (C-2 Im),

+
1
52.02 (C-3 Pyrazole), 158.64 (C-OCH ), 159.70 (C-OCH ); MS (EI+): m/z (%) 574.6 (M , 100);
3 3
Anal. Calcd. For C H N O : C, 79.42; H, 5.26; N, 9.75%. Found: C, 79.35; H, 5.19; N, 9.55%.
3
8
30
4
2
4
.2.2. 4-(1-(4-Bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(4-methoxyphenyl)-1-
phenyl-1H-pyrazole (2b)
From p-bromoaniline (0.38 g) and 1a (0.56 g), 2b was obtained as a white solid; m.p. 178 ºC;
-1
Yield: 0.79 g; 70%; IR (νmax-cm ; neat): 3127-2943 (C-H), 1600 (C=N), 1591 (C=C), 1249 &
2
1
1
016 (Ar -O-CH ); H NMR (CDCl , 500 MHz), δ: 3.81 (s, 3H; -OCH ), 6.39 (d, 2H, J = 8.6 Hz;
3
3
3
2
3
2
Ar -2H), 6.79 (d, 2H, J = 8.7 Hz; Ar -2H), 7.02 (d, 2H, J = 8.6 Hz; Ar -2H), 7.11 (d, 2H, J = 6.5
4
1
3
4
5
1
Hz; Ar -2H), 7.21-7.34 (m, 9H; Ar -1H, Ar -2H, Ar -3H & Ar -3H), 7.48 (t, 2H, J = 7.7 Hz; Ar -
5
1
2
H), 7.65 (d, 2H, J = 7.2 Hz; Ar -2H), 7.77 (d, 2H, J = 7.7 Hz; Ar -2H), 8.36 (s, 1H; H-5 Pyrazole);
C NMR (CDCl , 126 MHz), δ: 55.43 (-OCH ), 111.64 (C-4 Pyrazole), 113.75, 118.99, 121.62
1
3
3
3
(C-Br), 125.50, 126.80, 126.94, 127.41, 128.32, 128.35, 128.69, 129.01, 129.16, 129.47, 129.59
(CH-5 Pyrazole), 129.99, 130.24 (C-4 Im), 130.98, 131.37, 134.08, 134.94, 138.30 (C-5 Im),
+
1
39.69, 140.63 (C-2 Im), 151.86 (C-3 Pyrazole), 159.77 (C-OCH ); MS (EI+): m/z (%) 622.4 (M ,
3
+
8
8.0), 624.5 ([M+2] , 90.1); Anal. Calcd. For C H BrN O: C, 71.27; H, 4.36; N, 8.99%. Found:
3
7
27
4
C, 71.39; H, 4.46; N, 9.03%.
4
.2.3. 4-(1-(3,5-Dimethylphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(4-methoxyphenyl)-1-
phenyl-1H-pyrazole (2c)
From 3,5-dimethylaniline (0.27 g/0.27 mL) and 1a (0.56 g), 2c was obtained as a white solid; m.p.
-
1
1
1
72 ºC; Yield: 0.83 g; 81%; IR (νmax-cm ; neat): 3054-2837 (C-H), 1613 (C=N), 1596 (C=C),
2
1
249 & 1025 (Ar -O-CH ); H NMR (CDCl , 500 MHz), δ: 2.02 (s, 6H; 2×CH ), 3.85 (s, 3H; -
3
3
3
3
3
2
OCH ), 6.21 (s, 2H; Ar -2H), 6.70 (s, 1H; Ar -1H), 6.85 (d, 2H; J = 7.1 Hz; Ar -2H), 7.05-7.10
3
4
5
4
1
2
(
m, 2H; Ar -1H & Ar -1H), 7.20-7.28 (m, 4H; Ar -4H), 7.30-7.35 (m, 3H; Ar -2H & Ar -2H),
5
1
5
7
2
.38-7.43 (m, 2H; Ar -2H), 7.48-7.55 (m, 2H; Ar -2H), 7.67-7.71 (m, 2H; Ar -2H), 7.75-7.82 (m,
1
13
H; Ar -2H), 8.24 (s, 1H; H-5 Py); C NMR (CDCl , 125 MHz), δ: 21.04 (2×CH ), 55.34 (-
3
3
OCH ), 112.32 (C-4 Py), 113.73, 119.06, 125.65, 125.79, 126.63, 126.64, 127.39, 127.96, 128.28,
3
1
1
28.37, 129.22, 129.33, 129.36, 129.57, 130.47 (CH-5 Py), 130.88 (C-4 Im), 131.03, 134.69,
35.86, 137.84 (2×C-CH ), 137.96 (C-5 Im), 139.93, 140.73 (C-2 Im), 152.21 (C-3 Py), 159.62
3

+
(
C-OCH ); MS (EI+): m/z (%) 572.6 (M , 100); Anal. Calcd. For C H N O: C, 81.79; H, 5.63;
3 39 32 4
N, 9.78%. Found: C, 81.91; H, 5.76; N, 9.92%.
4
.2.4. 3-(4-Chlorophenyl)-4-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-
phenyl-1H-pyrazole (2d)
From p-anisidine (0.27 g) and 1b (0.56 g), 2d was obtained as a white solid; m.p. 202 ºC; Yield:
-1
3
0
.80 g; 78%; IR (νmax-cm ;neat): 3165-2840 (C-H), 1601 (C=N), 1578 (C=C), 1256 & 1073 (Ar -
1
O-CH ), 735 (C-Cl); H NMR (CDCl , 500 MHz), δ:3.70 (s, 1H; -OCH ), 6.48 (d, 2H, J = 9.0 Hz;
3
3
3
3
3
4
Ar -2H), 6.53 (d, 2H, J = 9.0 Hz; Ar -2H), 7.15 (dd, 2H, J = 7.6, 1.8 Hz; Ar -2H), 7.24-7.29 (m,
1
4
5
2
5
5
7
H; Ar -1H, Ar -3H & Ar -1H), 7.30 (d, 2H, J = 8.5 Hz; Ar -2H), 7.32-7.35 (m, 2H; Ar -2H),
2
1
.41 (d, 2H, J = 8.5 Hz; Ar -2H), 7.49 (t, 2H, J = 7.8 Hz; Ar -2H), 7.67 (dd, 2H, J = 7.2, 1.2 Hz;
5
1
13
Ar -2H), 7.75 (d, 2H, J = 7.8 Hz; Ar -2H), 8.24 (s, 1H; H-5 Py); C NMR (CDCl , 126 MHz), δ:
3
5
1
1
5.40 (-OCH ), 112.36 (C-4 Py), 113.60, 119.10, 126.83, 126.98, 127.39, 128.13, 128.34, 128.40,
3
28.55, 128.66, 128.84, 129.18, 129.64, 129.67 (CH-5 Py), 130.58, 130.62 (C-4 Im), 131.05,
31.52, 134.03 (C-Cl), 134.32, 138.03 (C-5 Im), 139.66, 140.42 (C-2 Im), 150.92 (C-3 Py), 158.73
+
+
(
C-OCH ); MS (EI+): m/z (%) 578.5 (M , 100), 580.5 ([M+2] , 35.0); Anal. Calcd. For
3
C H ClN O: C, 76.74; H, 4.70; N, 9.67%. Found: C, 76.61; H, 4.61; N, 9.74%.
3
7
27
4
4
1
.2.5. 3-(4-Chlorophenyl)-4-(1-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-phenyl-
H-pyrazole (2e)
From p-chloroaniline (0.28 g) and 1b (0.56 g), 2e was obtained as a white solid; m.p. 235 ºC (Lit
-1
[
37] m.p. 232 ºC); Yield: 0.71 g; 69%; IR (νmax-cm ; neat): 3099-3055 (C-H), 1589 (C=N), 1561
1
3
(
C=C), 756 (2×C-Cl); H NMR (CDCl , 500 MHz), δ: 6.44 (d, 2H, J = 8.2 Hz; Ar -2H), 6.87 (d,
3
3
4
2
4
2
H, J = 8.2 Hz; Ar -2H), 7.08 (d, 2H, J = 6.5 Hz; Ar -2H), 7.18-7.26 (m, 10H; Ar -4H, Ar -3H &
5
1
1
Ar -3H), 7.31 (t, 1H, J = 7.5 Hz; Ar -1H), 7.46 (t, 2H, J = 7.5 Hz; Ar -2H), 7.60 (d, 2H, J = 7.3
5
1
Hz; Ar -2H), 7.71 (d, 2H, J = 7.5 Hz; Ar -2H), 8.25 (s, 1H; H-5 Py); MS (EI+): m/z (%) 582.5
+
+
+
(
M , 100), 584.5 ([M+2] , 67.1), 586.4 ([M+4] , 13.4); Anal. Calcd. For C H Cl N : C, 74.10;
36 24 2 4
H, 4.15; N, 9.60%. Found: C, 73.92; H, 4.08; N, 9.50%.

4
1
.2.6. 4-(1-(4-Bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(4-chlorophenyl)-1-phenyl-
H-pyrazole (2f)
From p-bromoaniline (0.38 g) and 1b (0.56 g), 2f was obtained as a white solid; m.p. 220 ºC;
-1
Yield: 0.81 g; 73%; IR (νmax-cm ; neat): 3124-3059 (C-H), 1596 (C=N), 1561 (C=C), 763 (C-Cl);
1
3
3
H NMR (CDCl , 500 MHz), δ: 6.43 (d, 2H, J = 8.5 Hz; Ar -2H), 7.08 (d, 2H, J = 8.5 Hz; Ar -
3
4
4
2
4
2
1
7
H), 7.13 (d, 2H, J = 6.5 Hz; Ar -2H), 7.24-7.26 (m, 2H; Ar -2H), 7.28-7.33 (m, 8H; Ar -4H, Ar -
5
1
1
H & Ar -3H), 7.36 (t, 1H, J = 7.5 Hz; Ar -1H), 7.51 (t, 2H, J = 7.5 Hz; Ar -2H), 7.66 (d, 2H, J =
5
1
13
.3 Hz; Ar -2H), 7.78 (d, 2H, J = 7.5 Hz; Ar -2H), 8.35 (s, 1H; H-5 Py); C NMR (CDCl , 126
3
MHz), δ: 112.08 (C-4 Py), 119.11, 121.80 (C-Br), 127.04, 127.13, 127.42, 128.40, 128.42, 128.48,
1
1
28.77, 129.09, 129.17, 129.69, 130.10 (CH-5 Py), 130.77, 130.98, 131.34 (C-4 Im), 131.54,
34.03 (C-Cl), 134.22, 134.86, 138.54 (C-5 Im), 139.56, 140.14 (C-2 Im), 150.82 (C-3 Py); MS
+
+
+
(
EI+): m/z (%) 626.3 (M , 70.2), 628.4 ([M+2] , 100), 630.5 ([M+4] , 25.1); Anal. Calcd. For
C H ClBrN : C, 68.86; H, 3.85; N, 8.92%. Found: C, 68.72; H, 3.73; N, 9.06%.
3
6
24
4
4
.2.7. 3-(4-Chlorophenyl)-4-(1-(3,5-dimethylphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-
phenyl-1H-pyrazole (2g)
From 3,5-dimethylaniline (0.27 g/0.27 mL) and 1b (0.56 g), 2g was obtained as a white solid; m.p.
-1
1
70 ºC; Yield: 0.86 g; 84%; IR (νmax-cm ; neat): 3102-2840 (C-H), 1596 (C=N), 1561 (C=C), 744
1
3
(
C-Cl); H NMR (CDCl , 500 MHz), δ: 1.96 (s, 6H; 2×CH ), 6.11 (s, 2H; Ar -2H), 6.63 (s, 1H;
3
3
3
4
2
4
5
Ar -1H), 7.09 (dd, 2H, J = 7.0, 1.5 Hz; Ar -2H), 7.18-7.20 (m, 6H; Ar -2H, Ar -3H & Ar -1H),
1
5
2
7
.23-7.28 (m, 3H; Ar -1H & Ar -2H), 7.30 (d, 2H, J = 8.5 Hz; Ar -2H), 7.45 (t, 2H, J = 8.0 Hz;
1
5
1
Ar -2H), 7.60 (d, 2H, J = 7.3 Hz; Ar -2H), 7.70 (d, 2H, J = 8.0 Hz; Ar -2H), 8.19 (s, 1H; H-5 Py);
+
+
MS (EI+): m/z (%) 576.5 (M , 100), 578.5 ([M+2] , 34.1); Anal. Calcd. For C H ClN : C, 79.08;
3
8
29
4
H, 5.06; N, 9.71%. Found: C, 78.95; H, 4.86; N, 9.83%.
4
1
.2.8. 3-(4-Bromophenyl)-4-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-phenyl-
H-pyrazole (2h)
From p-anisidine (0.27 g) and 1c (0.80 g), 2h was obtained as a white solid; m.p. 200 ºC; Yield:
-1
1
0
.78 g; 82%; IR (νmax-cm ;neat): 3050-2839 (C-H), 1601 (C=N), 1578 (C=C), 1255 & 1013 (Ar -
1
3
O-CH ); H NMR (CDCl , 500 MHz), δ: 3.63 (s, 3H; -OCH ), 6.40 (d, 2H, J = 8.9 Hz; Ar -2H),
3
3
3
3
4
4
6
.44 (d, 2H, J = 8.9 Hz; Ar -2H), 7.07 (dd, 2H, J = 7.7, 2.0 Hz; Ar -2H), 7.15-7.19 (m, 4H, Ar -

5
5
1
2
3
8
H & Ar -1H), 7.21-7.23 (m, 2H; Ar -2H), 7.23-7.28 (m, 3H; Ar -1H & Ar -2H), 7.32 (d, 2H, J =
2
1
5
.4 Hz; Ar -2H), 7.41 (t, 2H, J = 7.8 Hz; Ar -2H), 7.57 (d, 2H, J = 7.4 Hz; Ar -2H), 7.67 (d, 2H,
1
13
J = 7.9 Hz; Ar -2H), 8.15 (s, 1H; H-5 Py); C NMR (CDCl , 126 MHz), δ: 55.42 (-OCH ), 112.50
3
3
(C-4 Py), 113.62, 119.12, 122.29 (C-Br), 126.81, 127.00, 127.40, 128.11, 128.34, 128.56, 128.72,
1
1
6
8
28.87, 129.51, 129.65, 130.64 (CH-5 Py), 130.65 (C-4 Im), 131.06, 131.35, 132.01, 134.47,
38.19 (C-5 Im), 139.69, 140.44 (C-2 Im), 150.95 (C-3 Py), 158.74 (C-OCH ); MS (EI+): m/z (%)
3
+
+
22.5 (M , 97.1), 624.5 ([M+2] , 100); Anal. Calcd. For C H BrN O: C, 71.27; H, 4.36; N,
3
7
27
4
.99%. Found: C, 71.42; H, 4.48; N, 9.06%.
4
1
.2.9. 3-(4-Bromophenyl)-4-(1-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-phenyl-
H-pyrazole (2i)
From p-chloroaniline (0.28 g) and 1c (0.80 g), 2i was obtained as a white solid; m.p. 194 ºC; (Lit
-1
[
37] m.p. 198 ºC);Yield: 0.68 g; 71%; IR (νmax-cm ; neat): 3100-2929 (C-H), 1589 (C=N), 1554
1
3
(
C=C), 756 (C-Cl); H NMR (CDCl , 500 MHz), δ: 6.45 (d, 2H, J = 9.0 Hz; Ar -2H), 6.90 (d, 2H,
3
3
4
2
J = 9.0 Hz; Ar -2H), 7.09 (dd, 2H, J = 7.9, 1.4 Hz; Ar -2H), 7.19 (d, 2H, J = 8.4 Hz; Ar -2H),
4
5
1
7
.22-7.30 (m, 5H; Ar -2H & Ar -3H), 7.33 (t, 1H, J = 8.0 Hz; Ar -1H), 7.37 (d, 2H, J = 8.4 Hz;
2
1
5
Ar -2H), 7.48 (t, 2H, J = 8.0 Hz; Ar -2H), 7.63 (dd, 2H, J = 8.5, 1.3 Hz; Ar -2H), 7.75 (d, 2H, J =
1
+
+
8
6
6
.0 Hz; Ar -2H), 8.37 (s, 1H; H-5 Py); MS (EI+): m/z (%) 626.5 (M , 73.5), 628.4 ([M+2] , 100),
+
30.5 ([M+4] , 28.0); Anal. Calcd. For C H ClBrN : C, 68.86; H, 3.85; N, 8.92%. Found: C,
3
6
24
4
8.79; H, 3.78; N, 8.70%.
4
.2.10. 3-(4-Bromophenyl)-4-(1-(3,5-dimethylphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-1-
phenyl-1H-pyrazole (2j)
From 3,5-dimethylaniline (0.27 g/0.27 mL) and 1c (0.80 g), 2j was obtained as a white solid; m.p.
-1
1
1
68 ºC; Yield: 0.77 g; 81%; IR (νmax-cm ; neat): 3143-2920 (C-H), 1596 (C=N), 1561 (C=C); H
3
3
NMR (CDCl , 500 MHz), δ:2.02 (s, 6H; 2×CH ), 6.17 (s, 2H; Ar -2H), 6.69 (s, 1H; Ar -1H), 7.14-
3
3
4
1
2
4
5
7
.15 (m, 2H; Ar -2H), 7.25-7.36 (m, 9H; Ar -1H, Ar -2H, Ar -3H & Ar -3H), 7.40 (d, 2H, J = 8.2
2
1
5
Hz; Ar -2H), 7.50 (t, 2H, J = 7.5 Hz; Ar -2H), 7.66 (d, 2H, J = 7.4 Hz; Ar -2H), 7.76 (d, 2H, J =
1
13
7
.5 Hz; Ar -2H), 8.30 (s, 1H; H-5 Py); C NMR (CDCl , 125 MHz), δ: 21.11 (2×CH ), 112.57
3 3
(
C-4 Py), 119.14, 122.20 (C-Br), 125.51, 126.79, 126.96, 127.41, 128.08, 128.33, 128.43, 129.32
CH-5 Py), 129.54, 129.64, 130.48 (C-4 Im), 130.59, 130.99, 131.35, 131.97, 134.39, 134.40,
(

1
35.62 (C-5 Im), 138.07 (2×C-CH ), 139.73, 140.14 (C-2 Im), 151.09 (C-3 Py); MS (EI+): m/z
3
+
+
(
%) 620.5 (M , 96.0), 622.5 ([M+2] , 100); Anal. Calcd. For C H BrN : C, 73.43; H, 4.70; N,
38 29 4
9
.01%. Found: C, 73.59; H, 4.86; N, 8.94%.
4
1
.2.11. 4-(1-(4-Chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(3-nitrophenyl)-1-phenyl
H-pyrazole (2k)
From p-chloroaniline (0.28 g) and 1d (0.58 g), 2k was obtained as pale yellow solid; m.p. 184 ºC;
-1
Yield: 0.78 g; 77%; IR (νmax-cm ; neat): 3089-2840 (C-H), 1599 (C=N), 1578 (C=C), 1533 &
1
3
1
346 (NO ), 757 (C-Cl); H NMR (CDCl , 500 MHz), δ: 6.56 (d, 2H, J = 8.7 Hz; Ar -2H), 6.90
2 3
3
4
4
(
d, 2H, J = 8.7 Hz; Ar -2H), 7.12 (dd, 2H, J = 8.0, 1.5 Hz; Ar -2H), 7.19-7.23 (m, 3H; Ar -3H),
5
1
2
7
.24-7.27 (m, 3H; Ar -3H), 7.34 (t, 1H, J = 9.0 Hz; Ar -1H), 7.42 (t, 1H; J = 8.0 Hz; Ar -1H), 7.48
1
5
(
t, 2H, J = 9.0 Hz; Ar -2H), 7.59 (dd, 2H, J = 7.1, 1.4 Hz; Ar -2H), 7.72 (dd, 2H, J = 9.0, 1.1 Hz;
1
2
2
Ar -2H), 7.85 (dt, 1H, J = 7.8, 1.3 Hz; Ar -1H), 8.08 (ddd, 1H, J = 8.2, 2.2, 1.0 Hz; Ar -1H), 8.19
2
+
(
s, 1H; H-5 Py), 8.24 (d, 1H, J = 1.9 Hz; Ar -1H); MS (EI+): m/z (%) 593.5 (M , 100), 595.5
+
(
[M+2] , 37.1); Anal. Calcd. For C H ClN O : C, 72.78; H, 4.07; N, 11.79%. Found: C, 72.91;
3
6
24
5
2
H, 4.14; N, 11.61%.
4
1
.2.12. 4-(1-(4-Methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(3-nitrophenyl)-1-phenyl-
H-pyrazole (2l)
From p-anisidine (0.27 g) and 1d (0.58 g), 2l was obtained as a white solid; m.p. 214 ºC; Yield:
-1
0
.85 g; 84%; IR (νmax-cm ; neat): 3061-2969 (C-H), 1599 (C=N), 1582 (C=C), 1508 & 1348
1
1
(
NO ), 1254 & 1023 (Ar -O-CH ); H NMR (CDCl , 500 MHz), δ: 3.63 (s, 3H; -OCH ), 6.45 (d,
2
3
3
3
3
3
4
2
7
1
H, J = 8.8 Hz; Ar -2H), 6.57 (d, 2H, J = 8.8 Hz; Ar -2H), 7.14 (d, 2H, J = 6.8 Hz; Ar -2H), 7.19-
4
5
1
2
.27 (m, 6H; Ar -3H & Ar -3H), 7.33 (t, 1H, J = 7.8 Hz; Ar -1H), 7.42 (t, 1H, J = 8.0 Hz; Ar -
1
5
H), 7.47 (t, 2H, J = 7.8 Hz; Ar -2H), 7.61 (d, 2H, J = 7.3 Hz; Ar -2H), 7.72 (d, 2H, J = 7.8 Hz;
1
2
2
Ar -2H), 7.90 (d, 1H, J = 7.7 Hz; Ar -1H), 8.09 (d, 1H, J = 8.8 Hz; Ar -1H), 8.17 (s, 1H; H-5 Py),
2
13
8
.30 (s, 1H; Ar -1H); C NMR (CDCl , 126 MHz), δ: 55.39 (-OCH ), 112.78 (C-4 Py), 113.73,
3 3
1
19.21, 122.68, 122.86, 126.85, 127.31, 127.38, 128.20, 128.32, 128.58, 128.69, 128.78, 129.05,
29.71, 130.53 (CH-5 Py), 130.78 (C-4 Im), 131.10, 133.86, 134.32, 134.70, 138.41 (C-5 Im),
39.49, 139.80 (C-2 Im), 148.25 (C-3 Py), 149.56 (C-NO ), 158.94 (C-OCH ); MS (EI+): m/z (%)
1
1
2
3
+
5
89.5 (M , 100); Anal. Calcd. For C H N O : C, 75.37; H, 4.62; N, 11.88%. Found: C, 75.54;
37 27 5 3
H, 4.81; N, 11.97%.

4
1
.2.13. 4-(1-(4-Bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(3-nitrophenyl)-1-phenyl-
H-pyrazole (2m)
From p-bromoaniline (0.38 g) and 1d (0.58 g), 2m was obtained as a yellow solid; m.p. 190 ºC;
-1
Yield: 0.88 g; 81%; IR (νmax-cm ; neat): 3088-2940 (C-H), 1598 (C=N), 1577 (C=C), 1533 &
1
3
1
8
1
2
346 (NO ); H NMR (CDCl , 500 MHz), δ: 6.50 (d, 2H, J = 8.2 Hz; Ar -2H), 7.06 (d, 2H, J =
2 3
3
4
4
5
.2 Hz; Ar -2H), 7.13 (d, 2H, J = 6.6 Hz; Ar -2H), 7.25-7.27 (m, 6H; Ar -3H & Ar -3H), 7.35 (t,
1
2
1
H, J = 7.5 Hz; Ar -H), 7.43 (t, 1H; J = 7.9 Hz; Ar -1H), 7.49 (t, 2H, J = 7.5 Hz; Ar -2H), 7.61 (d,
5
1
2
H, J = 7.3 Hz; Ar -2H), 7.75 (d, 2H, J = 7.5 Hz; Ar -2H), 7.83 (d, 1H, J = 7.4 Hz; Ar -1H), 8.09
2
2
13
(
d, 1H, J = 7.8 Hz; Ar -1H), 8.22 (s, 1H; H-5 Py), 8.31 (s, 1H; Ar -1H); C NMR (CDCl , 126
3
MHz), δ:112.08 (C-4 Py), 119.24, 122.08 (C-Br), 122.61, 122.78, 127.16, 127.17, 127.44, 128.40,
1
1
28.58, 128.84, 129.08, 129.22, 129.76, 129.92 (CH-5 Py), 130.03, 130.32 (C-4 Im), 131.04,
31.78, 133.59, 133.70, 134.41, 134.84, 138.70 (C-5 Im), 139.36, 139.43 (C-2 Im), 148.23 (C-3
+
+
Py), 149.31 (C-NO ); MS (EI+): m/z (%) 637.5 (M , 98.0), 639.4 ([M+2] , 100); Anal. Calcd. For
2
C H BrN O : C, 67.72; H, 3.79; N, 10.97%. Found: C, 67.65; H, 3.70; N, 10.92%.
3
6
24
5
2
4
.2.14. 4-(1-(3,5-Dimethylphenyl)-4,5-diphenyl-1H-imidazol-2-yl)-3-(3-nitrophenyl)-1-
phenyl-1H-pyrazole (2n)
From 3,5-dimethylaniline (0.27 g/0.27 mL) and 1d (0.58 g), 2n was obtained as a light yellow
-1
solid; m.p. 158 ºC; Yield: 0.88 g; 88%; IR (νmax-cm ; neat): 3084-2944 (C-H), 1598 (C=N), 1576
1
3
(
C=C), 1530 & 1344 (NO ); H NMR (CDCl , 500 MHz), δ:1.95 (s, 6H; Ar -2×CH ), 6.20 (s, 2H;
2 3 3
3
3
4
5
Ar -2H), 6.64 (s, 1H; Ar -1H), 7.10 (dd, 2H, J = 7.3, 1.5 Hz; Ar -2H), 7.17-7.26 (m, 6H; Ar -3H
4
1
2
&
Ar -3H), 7.33 (t, 1H, J = 8.0 Hz; Ar -H), 7.40 (t, 1H; J = 8.0 Hz; Ar -1H), 7.47 (t, 2H; J = 8.5,
1
5
1
7
.5 Hz; Ar -2H), 7.58 (d, 2H, J = 7.3 Hz; Ar -2H), 7.70 (d, 2H, J = 8.0 Hz; Ar -2H), 7.84 (d, 1H,
2
2
2
J = 7.7 Hz; Ar -1H), 8.08 (dd, 1H, J = 8.2, 1.2 Hz; Ar -1H), 8.15 (s, 1H; H-5 Py), 8.24 (s, 1H; Ar -
+
1
1
H); MS (EI+): m/z (%) 587.5 (M , 100); Anal. Calcd. For C H N O : C, 77.66; H, 4.97; N,
3
8
29
5
2
1.92%. Found: C, 77.53; H, 4.82; N, 11.74%.
4
.3. α-Glucosidase inhibition assay
The present assay involved the slightly modified Pierre’s protocol [30]where 10 µL (0.0234 units,
Sigma Inc.) of α-glucosidases (Cat No. 5003-1KU Type I; isolated from Saccharomyces
cereviciae) in phosphate buffer of 6.8 pH and 10 µL (0.5 mM) of a test compound was taken and

incubated the reaction mixture solution for 10 min at 37 ºC. The initial spectrophotometric
absorbance was taken at 400 nm. Later, 10 µL of 0.5 mMp-nitrophenyl-α- -glucopyranoside (code
D
No. N1377 from Sigma Inc) was added and absorbance change after 20 min incubation at 37 ºC
was recorded at 400 nm. Acarbose was a positive control and assays were executed in triplicates.
The IC values were calculated on EZ-Fit Enzyme Kinetics Software from Perrella Scientific Inc.
5
0
Amherst, USA.
.4. Molecular modeling studies
4
Homology model was built using oligo-1,6-glucosidase as a template protein. A search on BLAST
database revealed oligo-1,6-glucosidase (PDB ID: 3A4A) from Saccharomyces cerevisiae among
the top matched results and shares 72% identity and 85% similarity with α-glucosidase sequence
[31]. Sequence alignment was carried out using Needleman-Wunsch global alignment algorithm
embedded in Chimera. Structure was modelled using Modeller [32]. Ramachandran plot was
constructed using Molprobity [33]. Before docking studies, the structures of compounds were
optimized using semi empirical PM3 method in HyperChem [34]. Molecular docking studies were
carried out using BioSolveIT’s LeadIT software [35]. The docked conformations were visualized
in Discovery Studio Visualizer 4.0 [36].
Acknowledgements
The authors would like to express their gratitude to the Higher Education Commission of Pakistan
(HEC) for their financial support and awarding Indigenous as well as IRSIP Fellowships and other
research projects to Faryal Chaudhry.
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Highlights



Facile microwave irradiated synthetic strategy was adopted to synthesize imidazole-
pyrazole hybrids (2a-2n)
In-vitro bioevaluation of compounds (2a-2n) against α-glucosidase enzyme introduced
new potent inhibitors
Docking studies of compounds 2f and 2m revealed the probable mode of action