Synthesis and investigation of inhibitory activities of imidazole derivatives against the metallo-β-lactamase IMP-1

Article abstract of DOI:10.1016/j.bioorg.2019.103277

Mutations in bacteria can result in antibiotic resistance due to the overuse or abuse of β-lactam antibiotics. One strategy which bacteria can become resistance toward antibiotics is secreting of metallo β-lactamase enzymes that can open the lactam ring of the β-lactam antibiotic and inactivate them. This issue is a threat for human health and one strategy to overcome this situation is co-administration of β-lactam antibiotics with an inhibitor. So far, no clinically available inhibitors of metallo β-lactamases (MBLs) reported and the clinically inhibitors of serine β-lactamase are useless for MBLs. Accordingly, finding a potent inhibitor of the MBLs being very important. In this study, imidazole derivatives primarily were synthesized and their inhibitory activity were measured. Later in silico binding model was used to predict the configuration and conformation of the ligands into the active site of enzyme. Two molecules demonstrated with IC₅₀ of 39 μM and 46 μM against MBL (IMP-1).

Full text of DOI:10.1016/j.bioorg.2019.103277

Journal Pre-proofs
Synthesis and Investigation of inhibitory activities of Imidazole Derivatives
Against sthe Metallo-β-Lactamase IMP-1
Omid Khalili Arjomandi, Mahboubeh Kavoosi, Hadi Adibi
PII:
S0045-2068(19)31269-6
DOI:
https://doi.org/10.1016/j.bioorg.2019.103277
YBIOO 103277
Reference:
Bioorganic Chemistry
To appear in:
Received Date:
Revised Date:
Accepted Date:
3 August 2019
3 September 2019
11 September 2019
Please cite this article as: O.K. Arjomandi, M. Kavoosi, H. Adibi, Synthesis and Investigation of inhibitory activities
of Imidazole Derivatives Against sthe Metallo-β-Lactamase IMP-1, Bioorganic Chemistry (2019), doi: https://
doi.org/10.1016/j.bioorg.2019.103277
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover
page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will
undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing
this version to give early visibility of the article. Please note that, during the production process, errors may be
discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier Inc.

Synthesis and Investigation of inhibitory activities of Imidazole Derivatives Against
sthe Metallo-β-Lactamase IMP-1
Omid Khalili Arjomandia,b, Mahboubeh Kavoosic, Hadi Adibib
a The University of Queensland, School of Chemistry and Molecular Biosciences,
Brisbane, Qld 4072, Australia
b
Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of
Medical Sciences, Kermanshah, Iran
c Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
*Corresponding Authors:
Hadi Adibi, Tel.: +98 83 34 27 64 80 (Iran); Fax: +98 83 34 276 493;
Email: hadibi@kums.ac.ir.
https://orcid.org/0000-0003-2064-7875.
Omid Khalili Arjomandi, Tel.: +61 424 296 368 (Australia); Tel.: +98 912 289 72 16
(Iran);
Email: omid.arjomandi@uqconnect.edu.au.
https://orcid.org/0000-0002-1507-1691.
Mahboubeh Kavoosi, Email: mah.kavoosi@gmail.com; https://orcid.org/0000-0002-
8595-0966.

Abstract
Mutations in bacteria can result in antibiotic resistance due to the overuse or abuse of β-
lactam antibiotics. One strategy which bacteria can become resistance toward antibiotics
is secreting of metallo β-lactamase enzymes that can open the lactam ring of the β-lactam
antibiotic and inactivate them. This issue is a threat for human health and one strategy to
overcome this situation is co-administration of β-lactam antibiotics with an inhibitor. So
far, no clinically available inhibitors of metallo β-lactamases (MBLs) reported and the
clinically inhibitors of serine β-lactamase are useless for MBLs. Accordingly, finding a
potent inhibitor of the MBLs being very important. In this study, imidazole derivatives
primarily were synthesized and their inhibitory activity were measured. Later in silico
binding model was used to predict the configuration and conformation of the ligands into
the active site of enzyme. Two molecules demonstrated with IC50 of 39 µM and 46 µM
against MBL (IMP-1).

Introduction
Since their discovery in 1930, β-lactam antibiotics have become the standard treatment
for bacterial infections. The use of antibiotics is not monitored strictly in many parts of
the world and more than 50% of antibiotics are used without prescription worldwide.[1-
8] Due to the clinical overuse of antibiotics, many bacteria have become resistance against
β-lactam antibiotics with emergence of bacterial pathogens by secreting β-lactamases
(enzymes that inactivate these antibiotics by hydrolyzing their β-lactam ring) which cause
a matter of great concern. According to the mechanism of action, β-Lactamases are
classified into serine-β-lactamases (Classes A, C and D) and MBLs (Class B). MBLs are
further divided into three subclasses, B1, B2, and B3, depending on their amino acid
sequences and metal occupancies with one or two zinc (II) ions in the active site.[1-9]
The inactivation of β-lactam antibiotics by MBLs, is a significant threat to public health.
This issue can be controlled by either discovery of new antibiotics or the use of an inhibitor
co-administered with β-lactam antibiotics.[10, 11] At the current time, none of them are
clinically available. Moreover, MBLs are not inhibited by clavulanic acid, an inhibitor
commonly co-administered with β-lactam antibiotics for serine β-lactamases. Therefore,
there are currently no clinically available inhibitors of MBLs. In addition, MBLs are
characterized by αββα quaternary structural fold. The zinc ion(s) containing active site is
located at the edge of the ββ sheets in a pocket. The distance between two zinc ions is
roughly 3.4-4.4 Å for most of the MBLs. There is a bridging water molecule between two
zinc ions and the activated water molecule plays an important role in the hydrolysis of

antibiotics. In the active site of subclass B1, one of the zinc ions is coordinated by three
histidines (His116, His118 and His196) and a water molecule with the arrangement of
tetrahedral while the second zinc ion is coordinated by Asp120, Cys221, His263 and two
water molecules with the geometry of distorted trigonal bipyramidal (Figure 1).[12-20]
The aim of the research is to introduce a new series of MBLs inhibitors derived from
Imidazole and investigate their inhibitory activity.
Figure 1: Representative active-site pocket of MBL (IMP-1, subclass B1 of metallo β-
lactamase (MBLs), PDB Code: 1JJT). The active site is shown with yellow dash circle
and the left picture shows zinc ions and the amino acids of the active site of IMP-1.

Inhibitors of MBLs have been reported in different categories such as thiols,[21-27]
sulphates,[28] dicarboxylic acids,[29-34] trifluoromethylketones and alcohols,[35]
hydroxamates,[36] tetrazoles,[37] sulfonamides and sulfonyl hydrazones.[38]
Furthermore, compounds containing a zinc-binding sulfur atom comprise the first
category of MBLs inhibitors.[39]
Chemistry
In this study, to find a new series of inhibitors, two imidazole molecules (Figure 2),
reported by Vella et al.[40] with IC50 at the concentration of 1 mM against IMP-1, were
used as the lead compounds for synthesis of further analogues.
N
N
N
N
NH3
NH3
Figure 2: Lead compounds with IC50 at the concentration of 1 mM against IMP-1.[40]
Accordingly, a series of imidazole analogues with electron -donor and -acceptor (Figure
3) were synthesized and their inhibitory activity evaluated against IMP-1. In total, twenty-
four molecules and lead compounds were synthesized and 1H NMR and 13C NMR spectra
and HRMS were recorded. Some of these compounds are new and were not already
reported in the literature. All chemicals required for the process is commercially available
with inexpensive price which is an advantage to produce the final compound in a single

step. The other advantages of these chemicals are their stability as they are not easily
oxidized when access to fresh air or dissolved in water. Furthermore, because of the
hydrogen -donor and -acceptor groups, they are expected to be soluble in water at the time
of assay. These molecules were synthesized in one step by three different procedures.
R1
N
R2
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
R1=H, R2=phenyl
R1=CH3, R2=phenyl
R1=H, R2=4-methylphenyl
R1=CH3, R2=3-nitrophenyl
R1=H, R2=4-nitrophenyl
R1=CH3, R2=4-nitrophenyl
R1=H, R2=2-chloro-5-nitrophenyl
R1=CH3, R2=2-chloro-5-nitrophenyl
R1=CH3, R2=4-methylphenyl
R1=H, R2=2-chlorophenyl
R1=CH3, R2=2-chlorophenyl
R1=H, R2=4-chlorophenyl
R1=CH3, R2=4-chlorophenyl
R1=H, R2=4-methoxyphenyl
R1=CH3, R2=4-methoxyphenyl
R1=H, R2=1-naphthyl
(reference molecule)
R1=H, R2=3-anilinium
R1=CH3, R2=3-anilinium
(reference molecule)
R1=H, R2=4-anilinium
R1=CH3, R2=4-anilinium
R1=H, R2=2-chloro-5-anilinium
R1=CH3, R2=2-chloro-5-anilinium
R1=H, R2=4-hydroxyphenyl
R1=CH3, R2=4-hydroxyphenyl
R1=CH3, R2=1-naphthyl
R1=H, R2=3-nitrophenyl
Figure 3: two reference compounds and other imidazole derivatives
Compounds 1-18 were synthesized with the general procedure reported by Salvio et
al.[41] with the yield of 55-93% and the synthetic pathway of the reaction is shown in
Scheme 1. The 1H NMR and 13C NMR spectra were recorded and were in agreement with
compounds that already reported. For all known and new compounds, LRMS and HRMS
(positive mode) spectra were also recorded to make sure about the purity of these
compounds as a key factor at the time of assay.

R2
R1
R1
+
R2 Cl
NH
N
N
N
27
28
29
R1=H, R2=phenyl
R1=CH3, R2=phenyl
R1=H
R1=CH3
R2=phenyl
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
30
31
32
33
34
35
36
37
R2=4-methylphenyl
R2=2-chlorophenyl
R2=4-chlorophenyl
R2=4-methoxyphenyl
R2=1-naphthyl
R2=3-nitrophenyl
R2=4-nitrophenyl
R2=2-chloro-5-nitrophenyl
R1=H, R2=4-methylphenyl
R1=CH3, R2=4-methylphenyl
R1=H, R2=2-chlorophenyl
R1=CH3, R2=2-chlorophenyl
R1=H, R2=4-chlorophenyl
R1=CH3, R2=4-chlorophenyl
R1=H, R2=4-methoxyphenyl
R1=CH3, R2=4-methoxyphenyl
R1=H, R2=1-naphthyl
R1=CH3, R2=1-naphthyl
R1=H, R2=3-nitrophenyl
R1=CH3, R2=3-nitrophenyl
R1=H, R2=4-nitrophenyl
R1=CH3, R2=4-nitrophenyl
R1=H, R2=2-chloro-5-nitrophenyl
R1=CH3, R2=2-chloro-5-nitrophenyl
Scheme 1: Reagents and conditions: Dry CH3CN, K2CO3, reflux, and yield=55-93%.
Compounds 19-24 were synthesized in one step with the general procedure reported by
Roumen et al.[42] using Pd/C, HCl, H2 in ethanol shown in Scheme 2. These molecules
were prepared in a single step by a range yield of 80-92% and their chemical structures
1
13
were investigated by H NMR and C NMR spectra as well as recording LRMS and
HRMS (positive mode) spectra to investigate the purity of these compounds.

R1
R3
R1
R3
R4
N
R4
N
N
N
R2
R2
+
19
20
21
22
23
24
R1=H, R2=H, R3=NH3 , R4=H
13
14
15
16
17
18
R1=H, R2=H, R3=NO2, R4=H
R1=H, R2=H, R3=NO2, R4=CH3
R1=H, R2=NO2, R3=H, R4=H
R1=H, R2=NO2, R3=H, R4=CH3
R1=Chloro, R2=H, R3=NO2, R4=H
R1=Chloro, R2=H, R3=NO2, R4=CH3
+
R1=H, R2=H, R3=NH3 , R4=CH3
+
R1=H, R2=NH3 , R3=H, R4=H
+
R1=H, R2=NH3 , R3=H, R4=CH3
+
R1=Chloro, R2=H, R3=NH3 , R4=H
+
R1=Chloro, R2=H, R3=NH3 , R4=CH3
Scheme 2: Reagents and conditions: Pd/C (5%), H2, ethanol, HCl, reflux, 24h, yield: 80-
92%.
The general procedure reported by Vallée et al.[43] was used for the synthesis of
compounds 25 and 26 and the synthetic pathway is shown in Scheme 3. The mixture of
starting materials was heated up to 160 °C for half an hour without addition of solvent to
produce the products a range yield of 80-90%. These compounds are known and their 1H
NMR and 13C NMR spectra were in agreement with the reference.[43] For both molecules
LRMS and HRMS (positive mode) were recorded for the purpose of purity assessment.
R
R
HO
+
N
NH
N
N
OH
OH
27
28
56
25
26
R1=H
R1=CH3
R=H
R=CH3
Scheme 3: Reagents and conditions: 160 °C, 30 min, yield: 80-90%.

Biological Evaluation
Enzyme Expression and Purification
The IMP-1 enzyme, lacking the first 21 signal peptide amino acid residues, was expressed
and purified using the protocol of Vella et al.[40] Details of the expression and
purification of the enzyme are presented in the Supplementary data.
Kinetic Assays
CENTA (sodium (7R)-3-(((3-carboxylato-4-nitrophenyl)thio) methyl)-8-oxo-7-(2-
(thiophen-2-yl)acetamido)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate) was used
as the substrate for the study of kinetic assay and it was synthesized by a procedure
reported by Bebrone et al.[44] Inhibition assays for IMP-1 were performed in 96 well 400
µL multi-titre plates using a multi-plate spectrophotometer and the hydrolysis rate of
CENTA was measured at λ=405 nm. The initial screening assay was performed in
duplicate at concentrations of 1 mM, 500µM, 250µM, 100µM, 50µM and 10µM of
inhibitors, with CENTA (a type of cephalosporin) as the substrate and HEPESX (50 mM
HEPES, 0.1 M NaCl, 100 mM ZnCl2, pH 7.0) as the buffer at 25 °C. At the time of assay,
some compounds were insoluble at the concentration of 1 mM but were soluble at the
other concentrations. The final concentrations of enzyme and CENTA were 5 nM and 70
µM respectively. Bovine serum albumin (final concentration of 20 µg/ml) was added to

the enzyme to stability. For each well, 196 µL substrate and 4 µL inhibitor were added
followed by the addition of 200 µL of enzyme. The rate of hydrolysis of substrate was
recorded for 5 minutes. As per discussed, MBLs catalyze the hydrolysis of β-lactam
antibiotics (Figure 4) which eventually lead to their inactivation against bacteria. When
CENTA is hydrolyzed by MBLs, a yellow chromophore compound (3-carboxy-4-
nitrobenzenethiolate, ε = 6400 M-1 cm-1) is released which is detectable at the wavelength
of 405 nm. (Figure 4)
NH
O
S
S
S
S
O
NH
OH
S
MBLs
S
N
+
O
NO2
CO2
CO2
O
N
NO2
CO2
CO2
CENTA
Chromophore
Figure 4: Hydrolysis of CENTA by MBLs and releasing a yellow chromophore.
The results indicate that nearly 90% of all compounds are at least 5 to 10-fold more active
than reference compounds (Table 1). In addition, more than half of the synthesized
molecules show IC50 nearly 100 µM while the reference molecules show IC50 at 1 mM.
Furthermore, compounds with R = methyl group are more potent than analogues with
hydrogen group. This issue can be explained by the better fitting or locking of these
inhibitors into the active site of enzyme.

For calculation of IC50, the reciprocal rate (1/V) plotted versus concentration of inhibitors
in Excel and the trendline equation was found. IC50 was then estimated using the fitted
line equation where the x-intercept=IC50.
In this group, compound 16 with the nitro substitution, an electron donor group, in para
position of aromatic phenyl ring shows the highest inhibition activity with IC50 of 39 µM.
Compound 12 is the second potent enzyme-based inhibitor with IC50 of 46 µM.

Table 1: IC50 of imidazole derivatives 1-26 against IMP-1
Compound
IC50 (µM)
>100
>100
>100
89.3
Compound
IC50 (µM)
84.7
1
14
15
16
17
18
19*
20
21*
22
23
24
25
26
2
>100
39.0
3
4
>100
>100
970
5
>100
88.6
6
7
88.1
64.6
8
81.5
962
9
>100
92.5
64.7
10
>100
>100
>100
97.6
11
>100
46.0
12
13
>100
*Reference compounds

Computational Modeling
For the study of computational modeling, the crystal structure of IMP-1 enzyme (PDB
code: 1JJT) was downloaded from Protein Data Bank (PDB) and Chain B was deleted as
the topologies of the active sites of both chain A and chain B are identical. Further
elimination for Chain A was carried out by removing water molecules (solvents), single
Zinc ion and the coordinated ligand of the active site. The cavity of the active site with
two zinc ions was set by MolDock for the investigation of docking study. To predict the
conformation and configuration of ligands into the active site of enzyme, synthesized
molecules as well as reference compounds were docked into the active site of IMP-1. The
computational modeling showed that all compounds are in proper size to fit into the active
site of IMP-1 as it is located in the pocket of enzyme and apparently larger molecules can't
get easily access to this part. The in-silico modeling shows different configurations and
conformations for this series of compounds into the active site. For instance, compounds
that have nitro substitution are coordinated into zinc ions via the oxygen of nitro group
while the other molecules without electron-donor groups are coordinated into zinc ions
via the lone pair of nitrogen of imidazole. Moreover, the molecules with electron-donor
groups can create further interactions with amino acids of the active sites. The
investigation of computational modeling of ligand 16 (figure 5) predicted that one of the
oxygen atoms of nitro group is coordinated to both zinc atoms with the predicted distances
of 5.10 Å (Zn1) and 3.36 Å (Zn2) and the other oxygen of nitro group predicted to form
hydrogen bonds with Gly232 and Lys224 with the distances of 1.70 Å and 2.04 Å

respectively. The aromatic ring of this ligand can also create a π-π interaction with
aromatic ring of TRP64 which predicted to increase the potency of inhibition activity.
Figure 5: Interactions of ligand 16 at the active site of IMP-1 (PDB: 1JJT). Atom colors
are as follows: blue–nitrogen, red–oxygen, grey–carbon and yellow-zinc atom (of IMP-
1), and red–oxygen, blue–nitrogen, green–carbon, and yellow–sulfur (on inhibitor).
Conclusion
In order to introduce a new class of inhibitors of IMP-1, twenty-four molecules derived
from imidazole were synthesized and their inhibitory activity and IC50 were measured.
The results demonstrated that all molecules are more potent than reference molecules
against IMP-1. Furthermore, two compounds show the best IC50 with the values of 39 µM
and 46 µM in this series of molecules. The study demonstrated that the addition of the
electron-donor group to imidazole derivatives can increase the potency of inhibitory
activity against IMP-1 with better coordination to zinc ions of the active site.

Experimental
Synthesis
All chemicals were purchased from Sigma-Aldrich, Merck and Fluka chemical
companies. All NMR experiments were recorded on Bruker AVANCE 500, 400 or 300
MHz spectrometers. Chemical shifts are reported in parts per million (ppm) on a δ scale
and referenced to the residual solvent peak (1H, 7.24 ppm, 13C, 77.0 ppm for CDCl3; 1H,
13
1
13
2.49 ppm, C, 39.5 ppm for DMSO-d6; H, 3.30 ppm, C, 49.5 ppm for CD3OD).
Coupling constants (J) are reported in Hertz. Multiplicities of the peaks are abbreviated
as follows: s for singlet, bs for broad singlet, d for doublet, t for triplet, and q for quartet.
Low- and high- resolution EI-MS were measured on a Finnigan MAT 900 XL-Trap mass
spectrometer in positive and negative ionization mode. LR-ESI were recorded on a Bruker
HCT 3D Ion Trap and HR-ESI were performed on a BrukerMicrOTof-Q with the
DIONEX Ultimate 3000 LC in positive and negative electrospray ionization mode, with
CH3OH as solvent. 1H NMR and 13C NMR spectra are shown in the Supplementary data.
General procedure 1:
Compounds 1-18 were synthesized using the following general procedure reported by
Salvio et al.[41] A mixture of potassium carbonate (2.0 g, 14.4 mmol), imidazole
derivatives 27-28 (32.9 mmol) and compounds 29-37 (4.7 mmol) in dry acetonitrile (50
ml) was heated under reflux and the progress of the reaction was monitored by TLC. Then

the solvent was evaporated under the vacuum and the residue was dissolved in DCM (100
ml) *. The organic layer was washed with saturated sodium bicarbonate aqueous solution
(2×50 ml), passed through diatomaceous earth, dried over sodium sulfate, evaporated
under the vacuum, and purified by flash column chromatography (ethyl acetate-hexane 0-
100%)** to give the products 1-18.
*Note 1: Ethyl acetate (200 ml) was used for compounds 17 and 18.
**Note 2: Compounds 17 and 18 (ethyl acetate-methanol 0-100%)
General procedure 2:
The general procedure reported by Roumen et al.[43] was modified and used (HCl 2M
was added in the reaction) for the synthesis of hydrochloride salt of the molecules 19-24.
A mixture of compounds 13-18 (4.6 mmol), HCl 2M (4 ml), Pd/C 5% (100 mg) in ethanol
(20 ml) was hydrogenated under reflux at atmospheric pressure for 24 hours. The organic
solvent was evaporated under the vacuum and water (50 ml) was added and stirred for 10
minutes and the solid impurity was filtered off then water phase was washed with ethyl
acetate (2×50 ml), passed through diatomaceous earth, and evaporated under the vacuum
and dried in oven at 40 °C to give the products 19-24.

General procedure 3:
Compounds 25-26 were synthesized using the following general procedure reported by
Vallée et al.[43] A mixture of imidazole derivatives 27-28 (40 mmol) and 4-
hydroxybenzyl alcohol 56 (1.0 g, 8.0 mmol) was heated at 160 °C for half an hour which
resulted dark brown oil. The mixture of the reaction was then cooled down to 50-80° C
and added to a stirring hot water (100 ml) resulted brown solid residue which was filtered
off. Then the residue was transferred to a round bottom flask and ethyl acetate (2×50 ml)
was added and stirred for 10 min and then it was filtered off and dried in the oven at 40
°C to give the products 25-26.
1-Benzyl-1H-imidazole (1)
1
Pale yellow solid, 0.61 g (82 %). H NMR (300 MHz, CDCl3): δ 7.51 (1H, s, NCHN),
7.37-7.25 (3H, m, Ph-H), 7.16-7.08 (2H, m, Ph-H), 7.06 (1H, s, NCHCHNCH2), 6.87 (1H,
s, NCHCHNCH2), 5.08 (2H, s, CH2). 13C NMR (75 MHz, CDCl3): δ 137.4 (Ar-C), 136.1
(Ar-C), 129.7 (Ar-C), 128.9 (Ar-C), 128.2 (Ar-C), 127.2 (Ar-C), 119.2 (Ar-C), 50.7
(CH2). HRMS calculated for C10H11N2 [M+H]+ 159.0922, found 159.0924. m.p. 71-73 °C
(lit. m.p. 71-72 °C).[41] The NMR spectra are in agreement with the literature.[41]
1-Benzyl-2-methyl-1H-imidazole (2)
Pale yellow oil, 0.65 g (80 %). 1H NMR (400 MHz, CDCl3): δ 7.30-7.17 (3H, m, Ph-H),
6.98 (2H, d, J=1.5 Hz, Ph-H), 6.88 (1H, d, J=1.3 Hz, NCHCHNCH2), 6.76 (1H, d, J=1.4
Hz, NCHCHNCH2), 4.95 (2H, s, CH2), 2.45 (3H, s, CH3). 13C NMR (100 MHz, CDCl3):

δ 144.5 (Ar-C), 136.1 (Ar-C), 128.6 (Ar-C), 127.6 (Ar-C), 126.9 (Ar-C), 126.3 (Ar-C),
119.6 (Ar-C), 49.3 (CH2), 12.8 (CH3). HRMS calculated for C11H13N2 [M+H]+ 173.1073,
found 173.1077. The NMR spectra are in agreement with the literature.[45]
1-(4-Methylbenzyl)-1H-imidazole (3)
Brown solid, 0.66 g (81%). 1H NMR (300 MHz, CDCl3): δ 7.44 (1H, s, NCHN), 7.08 (2H,
d, J=7.9 Hz, Ph-H), 7.04-6.94 (3H, m, Ph-H & NCHCHNCH2), 6.81 (1H, t, J=1.2 Hz,
NCHCHNCH2), 4.97 (2H, s, CH2), 2.27 (3H, s, CH3). 13C NMR (75 MHz, CDCl3): δ 137.7
(Ar-C), 137.1 (Ar-C), 132.9 (Ar-C), 129.4 (Ar-C), 129.3 (Ar-C), 127.0 (Ar-C), 118.9 (Ar-
C), 50.2 (CH2), 20.8 (CH3). HRMS calculated for C11H13N2 [M+H]+ 173.1073, found
173.1076. m.p. 49-50 °C (lit. m.p. 49-50 °C).[46] The NMR spectra are in agreement with
the literature.[46]
2-Methyl-1-(4-methylbenzyl)-1H-imidazole (4)
Brown oil, 0.69 g (79%). 1H NMR (500 MHz, CDCl3): δ 7.09 (2H, d, J=7.9 Hz, Ph-H),
6.94-6.86 (3H, m, Ph-H & NCHCHNCH2), 6.77 (1H, d, J=1.3 Hz, NCHCHNCH2), 4.94
(2H, s, CH2), 2.28 (6H, s, both CH3). 13C NMR (125 MHz, CDCl3): δ 144.7 (Ar-C), 137.5
(Ar-C), 133.2 (Ar-C), 129.4 (Ar-C), 127.1 (Ar-C), 126.5 (Ar-C), 119.7 (Ar-C), 49.3
(CH2), 20.9 (Ar-Me), 13.0 (Imidazole-Me). HRMS calculated for C12H15N2 [M+H]+
187.1230, found 187.1227.

1-(2-Chlorobenzyl)-1H-imidazole (5)
Brown oil, 0.78 g (86%). 1H NMR (300 MHz, CDCl3): δ 7.48 (1H, s, NCHN), 7.35-7.29
(1H, m, Ph-H), 7.25-7.11 (2H, m, Ph-H), 7.01 (1H, t, J=1.1 Hz, NCHCHNCH2), 6.90-
6.84 (2H, m, Ph-H & NCHCHNCH2), 5.14 (2H, s, CH2). 13C NMR (75 MHz, CDCl3): δ
137.4 (Ar-C), 133.8 (Ar-C), 132.8 (Ar-C), 129.6 (Ar-C), 129.5 (Ar-C), 129.4 (Ar-C),
128.8 (Ar-C), 127.2 (Ar-C), 119.1 (Ar-C), 48.1 (CH2). HRMS calculated for C10H10ClN2
[M+H]+ 193.0527, found 193.0534. Rf= 0.13 (20/80 ethyl acetate/petroleum ether). The
NMR spectra are in agreement with the literature.[47]
1-(2-Chlorobenzyl)-2-methyl-1H-imidazole (6)
Brown solid, 0.83 g (85 %). 1H NMR (300 MHz, CDCl3): δ 7.35 (1H, dd, J=7.3, 1.3 Hz,
Ph-H), 7.24-7.10 (2H, m, Ph-H), 6.92 (1H, d, J=1.3 Hz, NCHCHNCH2), 6.77 (1H, d,
J=1.3 Hz, NCHCHNCH2), 6.60 (1H, d, J=6.5 Hz, Ph-H), 5.07 (2H, s, CH2), 2.28 (3H, s,
13
CH3). C NMR (75 MHz, CDCl3): δ 145.0 (Ar-C), 134.0 (Ar-C), 132.3 (Ar-C), 129.5
(Ar-C), 129.1 (Ar-C), 127.6 (Ar-C), 127.5 (Ar-C), 127.3 (Ar-C), 119.8 (Ar-C), 47.2
(CH2), 12.8 (CH3). HRMS calculated for C11H12ClN2 [M+H]+ 207.0684, found 207.0687.
m.p=62.5-63.5 °C.
1-(4-Chlorobenzyl)-1H-imidazole (7)
Pale yellow oil, 0.84 g (93 %). 1H NMR (300 MHz, CDCl3): δ 7.30 (1H, s, NCHN), 7.06
(2H, d, J=8.5 Hz, Ph-H), 6.88 (3H, m, Ph-H & NCHCHNCH2), 6.67 (1H, t, J=1.3 Hz,

13
NCHCHNCH2), 4.84 (2H, s, CH2). C NMR (75 MHz, CDCl3): δ 136.7 (Ar-C), 134.3
(Ar-C), 133.3 (Ar-C), 129.2 (Ar-C), 128.4 (Ar-C), 128.1 (Ar-C), 118.6 (Ar-C), 49.3
(CH2). HRMS calculated for C10H10ClN2 [M+H]+ 193.0527, found 193.0533. The NMR
spectra are in agreement with the literature.[46]
1-(4-Chlorobenzyl)-2-methyl-1H-imidazole (8)
Brown viscous oil, 0.85 g (88 %). 1H NMR (500 MHz, CDCl3): δ 7.29 (2H, t, J=13.6 Hz,
Ph-H), 6.98-6.92 (3H, m, Ph-H & NCHCHNCH2), 6.80 (1H, d, J=1.4 Hz,
NCHCHNCH2), 5.00 (2H, s, CH2), 2.31 (3H, s, CH3). 13C NMR (125 MHz, CDCl3): δ
144.9 (Ar-C), 134.8 (Ar-C), 133.9 (Ar-C), 129.2 (Ar-C), 128.0 (Ar-C), 127.4 (Ar-C),
119.8 (Ar-C), 49.1 (CH2), 13.0 (CH3). HRMS calculated for C11H12ClN2 [M+H]+
207.0684, found 207.0685.
1-(4-Methoxybenzyl)-1H-imidazole (9)
Pale yellow solid, 0.80 g (90%). 1H NMR (300 MHz, CDCl3): δ 7.42 (1H, s, NCHN), 7.03
(3H, t, J=8.5 Hz, Ph-H & NCHCHNCH2), 6.85-6.78 (3H, m, Ph-H & NCHCHNCH2),
4.97 (2H, s, CH2), 3.73 (3H, s, CH3). 13C NMR (75 MHz, CDCl3): δ 159.3 (Ar-C), 137.1
(Ar-C), 129.5 (Ar-C), 128.7 (Ar-C), 128.0 (Ar-C), 119.0 (Ar-C), 114.2 (Ar-C), 55.1
(CH3), 50.1 (CH2). HRMS calculated for C11H12N2NaO [M+Na]+ 211.0842, found
211.0846. m.p. 57-59 °C (lit. m.p. 57-58 °C).[48] The NMR spectra are in agreement with
the literature.[48]

1-(4-Methoxybenzyl)-2-methyl-1H-imidazole (10)
Brown viscous oil, 0.85 g (89%). 1H NMR (500 MHz, CDCl3): δ 6.93 (2H, d, J=11.0
Hz, Ph-H), 6.84 (1H, d, J=1.3 Hz, NCHCHNCH2), 6.78 (2H, d, J=11.0 Hz, Ph-H), 6.72
(1H, d, J=1.3 Hz, NCHCHNCH2), 4.87 (2H, s, CH2), 3.69 (3H, s, CH3O), 3.25 (3H, s,
CH3). 13C NMR (125 MHz, CDCl3): δ 159.0 (Ar-C), 144.5 (Ar-C), 128.1 (Ar-C), 127.9
(Ar-C), 126.9 (Ar-C), 119.5 (Ar-C), 114.0 (Ar-C), 55.0 (CH3O), 49.0 (CH2), 12.9 (CH3).
HRMS calculated for C12H15N2O [M+H]+ 203.1179, found 203.1179.
1-(Naphthalen-1-ylmethyl)-1H-imidazole (11)
Dark brown viscous oil, 0.88 g (90 %). 1H NMR (400 MHz, CDCl3): δ 7.93-7.81 (3H, m,
naphthyl), 7.66 (1H, s, NCHN), 7.56-7.47 (2H, m, naphthyl), 7.43 (1H, dd, J=8.2, 7.0 Hz,
naphthyl), 7.18 (1H, d, J=7.0 Hz, naphthyl), 7.09 (1H, s, NCHCHNCH2), 6.92 (1H, s,
NCHCHNCH2), 5.59 (2H, s, CH2). 13C NMR (100 MHz, CDCl3): δ 137.3 (Ar-C), 133.8
(Ar-C), 131.0 (Ar-C), 130.8 (Ar-C), 129.4 (Ar-C), 129.0 (Ar-C), 128.9 (Ar-C), 127.1 (Ar-
C), 126.4 (Ar-C), 126.3 (Ar-C), 125.4 (Ar-C), 122.3 (Ar-C), 119.5 (Ar-C), 48.9 (CH2).
HRMS calculated for C14H13N2 [M+H]+ 209.1073, found 209.1077. The NMR spectra are
in agreement with the literature.[49]
2-Methyl-1-(naphthalen-1-ylmethyl)-1H-imidazole (12)
1
Dark brown solid, 0.84 g (80 %). H NMR (400 MHz, CDCl3): δ 7.90-7.71 (3H, m,
naphthyl), 7.56-7.46 (2H, m, naphthyl), 7.33 (1H, dd, J=8.2, 7.2 Hz, naphthyl), 6.94 (1H,

d, J=1.3 Hz, NCHCHNCH2), 6.75 (1H, dd, J=7.1, 1.0 Hz, naphthyl), 6.72 (1H, d, J=1.4
Hz, NCHCHNCH2), 5.39 (2H, s, CH2), 2.32 (3H, s, CH3). 13C NMR (100 MHz, CDCl3):
δ 144.9 (Ar-C), 133.4 (Ar-C), 131.5 (Ar-C), 130.2 (Ar-C), 128.8 (Ar-C), 128.4 (Ar-C),
127.2 (Ar-C), 126.6 (Ar-C), 126.0 (Ar-C), 125.3 (Ar-C), 124.1 (Ar-C), 122.0 (Ar-C),
119.8 (Ar-C), 47.2 (CH2), 12.8 (CH3). HRMS calculated for C15H15N2 [M+H]+ 223.1230,
found 223.1234. m.p. 103.5-104.5 °C.
1-(3-Nitrobenzyl)-1H-imidazole (13)
Brown solid, 0.67 g (70 %). 1H NMR (300 MHz, DMSO-d6): δ 8.18-8.08 (2H, m, Ph-H),
7.82 (1H, s, NCHN), 7.73-7.60 (2H, m, Ph-H), 7.25 (1H, t, J=1.4 Hz, NCHCHNCH2),
13
6.93 (1H, t, J=1.0 Hz, NCHCHNCH2), 5.36 (2H, s, CH2). C NMR (75 MHz, DMSO-
d6): δ 147.9 (Ar-C), 140.1 (Ar-C), 137.6 (Ar-C), 134.1 (Ar-C), 130.3 (Ar-C), 129.0 (Ar-
C), 122.7 (Ar-C), 122.1 (Ar-C), 119.6 (Ar-C), 48.5 (CH2). HRMS calculated for
C10H10N3O2 [M+H]+ 204.0768, found 204.0767. m.p. 95-97 °C (lit. m.p. 95-97 °C).[50]
The NMR spectra are in agreement with the literature.[51]
2-Methyl-1-(3-nitrobenzyl)-1H-imidazole (14)
Brown solid, 0.91 g (89 %). 1H NMR (500 MHz, CDCl3): δ 8.14 (1H, m, Ph-H), 7.95 (1H,
s, Ph-H), 7.51 (1H, t, J=8.0 Hz, Ph-H), 7.29 (1H, d, J=8.0 Hz, Ph-H), 6.97 (1H, s,
NCHCHNCH2), 6.84 (1H, s, NCHCHNCH2), 5.14 (2H, s, CH2), 2.31 (3H, s, CH3). 13C
NMR (125 MHz, CDCl3): δ 148.6 (Ar-C), 144.8 (Ar-C), 138.6 (Ar-C), 132.3 (Ar-C),

130.1 (Ar-C), 128.1 (Ar-C), 123.0 (Ar-C), 121.5 (Ar-C), 119.7 (Ar-C), 48.9 (CH2), 13.1
(CH3). HRMS calculated for C11H12N3O2 [M+H]+ 218.0924, found 218.0929. m.p. 82-83
°C.
1-(4-Nitrobenzyl)-1H-imidazole (15)
1
Brown solid, 0.86 g (90 %). H NMR (300 MHz, DMSO-d6): δ 8.19 (2H, d, J=8.5 Hz,
Ph-H), 7.55 (1H, s, NCHN), 7.25 (2H, d, J=8.5 Hz, Ph-H), 7.11 (1H, t, J=1.2 Hz,
NCHCHNCH2), 6.88 (1H, t, J=1.2 Hz, NCHCHNCH2), 5.23 (2H, s, CH2). 13C NMR (75
MHz, DMSO-d6): δ 147.8 (Ar-C), 143.4 (Ar-C), 137.5 (Ar-C), 130.4 (Ar-C), 127.7 (Ar-
C), 124.2 (Ar-C), 119.2 (Ar-C), 49.9 (CH2). HRMS calculated for C10H10N3O2 [M+H]+
204.0768, found 204.0770. m.p. 55-56 °C (lit. m.p. 55-56 °C).[52] The NMR spectra are
in agreement with the literature.[53]
2-Methyl-1-(4-nitrobenzyl)-1H-imidazole (16)
Black solid, 0.90 g (88%). 1H NMR (300 MHz, CDCl3): δ 8.19 (2H, d, J=8.8 Hz, Ph-H),
7.16 (2H, d, J=8.6 Hz, Ph-H), 7.00 (1H, s, NCHCHNCH2), 6.85 (1H, s, NCHCHNCH2),
5.16 (2H, s, CH2), 2.32 (3H, s, CH3). 13C NMR (75 MHz, CDCl3): δ 147.7 (Ar-C), 143.4
(Ar-C), 127.7 (Ar-C), 127.2 (Ar-C), 124.5 (Ar-C), 124.3 (Ar-C), 119.9 (Ar-C), 49.1
(CH2), 12.9 (CH3). HRMS calculated for C11H12N3O2 [M+H]+ 218.0924, found 218.0927.
m.p. 96-97 °C (lit. m.p. 95-96 °C). The NMR spectra are in agreement with the
literature.[54]

1-(2-Chloro-5-nitrobenzyl)-1H-imidazole (17)
Brown solid, 0.61 g (55 %). 1H NMR (500 MHz, CD3OD): δ 8.17 (1H, dd, J=8.8, 2.6 Hz,
Ph-H), 7.89 (1H, d, J=2.7 Hz, Ph-H), 7.83 (1H, s, NCHN), 7.70 (1H, d, J=8.8 Hz, Ph-H),
7.19 (1H, t, J=1.3 Hz, NCHCHNCH2), 7.05 (1H, t, J=1.2 Hz, NCHCHNCH2), 5.46 (2H,
s, CH2). 13C NMR (125 MHz, CD3OD): δ 148.4 (Ar-C), 140.9 (Ar-C), 139.2 (Ar-C), 138.0
(Ar-C), 132.1 (Ar-C), 129.8 (Ar-C), 125.5 (Ar-C), 125.0 (Ar-C), 121.1 (Ar-C), 48.8
(CH2). HRMS calculated for C10H9ClN3O2 [M+H]+ 238.0378, found 238.0386. m.p. 107-
109 °C. The NMR spectra are in agreement with the literature.[51]
1-(2-Chloro-5-nitrobenzyl)-2-methyl-1H-imidazole (18)
Dark brown solid, 0.65 g (55 %). 1H NMR (300 MHz, CD3OD): δ 8.16 (1H, dd, J=8.8,
2.7 Hz, Ph-H), 7.72 (1H, d, J=8.7 Hz, Ph-H), 7.56 (1H, d, J=2.6 Hz, Ph-H), 7.06 (1H, d,
J=1.3 Hz, NCHCHNCH2), 6.94 (1H, d, J=1.3 Hz, NCHCHNCH2), 5.37 (2H, s, CH2),
2.34 (3H, s, CH3). 13C NMR (75 MHz, CD3OD): δ 148.5 (Ar-C), 146.7 (Ar-C), 140.5 (Ar-
C), 137.9 (Ar-C), 132.2 (Ar-C), 127.8 (Ar-C), 125.3 (Ar-C), 123.9 (Ar-C), 121.5 (Ar-C),
48.0 (CH2), 12.5 (CH3). HRMS calculated for C11H11ClN3O2 [M+H]+ 252.0534, found
252.0537. m.p. 88-90 °C.
1-(3-Aminobenzyl)-1H-imidazol-3-ium (19)
Pale brown solid, 0.79 g (82 %). 1H NMR (400 MHz, DMSO-d6): δ 9.39 (1H, s, NHCHN),
7.79 (1H, t, J=1.7 Hz, NHCHCHN), 7.72 (1H, t, J=1.7 Hz, NHCHCHN), 7.45 (1H, t,

13
J=7.8 Hz, Ph-H), 7.34-7.23 (3H, m, Ph-H), 5.50 (2H, s, CH2). C NMR (100 MHz,
DMSO-d6): δ 136.8 (Ar-C), 135.5 (Ar-C), 134.8 (Ar-C), 130.2 (Ar-C), 126.0 (Ar-C),
122.4 (Ar-C), 122.1 (Ar-C), 121.4 (Ar-C), 120.3 (Ar-C), 51.0 (CH2). HRMS calculated
for C10H12N3 [M]+ 174.1031, found 174.1034. m.p. 217-218 °C.
1-(3-Aminobenzyl)-2-methyl-1H-imidazol-3-ium (20)
1
Pale yellow solid, 0.82 g (80 %). H NMR (300 MHz, DMSO-d6): δ 8.28-8.18 (2H, m,
Ph-H), 7.81-7.66 (3H, m, Ph-H & NHCHCHN), 7.62 (1H, d J=2.1 Hz, NHCHCHN), 5.56
13
(2H, s, CH2), 2.63 (3H, s, CH3). C NMR (75 MHz, DMSO-d6): δ 148.0 (Ar-C), 144.6
(Ar-C), 136.7 (Ar-C), 134.6 (Ar-C), 130.6 (Ar-C), 123.4 (Ar-C), 122.9 (Ar-C), 122.2 (Ar-
C), 118.3 (Ar-C), 48.9 (CH2), 10.5 (CH3). HRMS calculated for C11H14N3 [M]+ 188.1188,
found 188.1191. m.p. 219-220 °C.
1-(4-Aminobenzyl)-1H-imidazol-3-ium (21)
1
Brown solid, 0.81 g (82 %). H NMR (300 MHz, DMSO-d6): δ 9.34 (1H, t, J=1.5 Hz,
NHCHN), 7.78 (1H, t, J=1.6 Hz, NHCHCHN), 7.68 (1H, t, J=1.6 Hz, NHCHCHN), 7.45
(2H, d, J=8.5 Hz, Ph-H), 7.27 (2H, d, J=8.5 Hz, Ph-H), 5.43 (2H, s, CH2). 13C NMR (75
MHz, DMSO-d6): δ 135.3 (Ar-C), 134.0 (Ar-C), 133.6 (Ar-C), 129.5 (Ar-C), 122.9 (Ar-
C), 121.9 (Ar-C), 120.2 (Ar-C), 50.9 (CH2). HRMS calculated for C10H12N3 [M]+
174.1031, found 174.1032. m.p. 209-210 °C. The 1H NMR spectrum of neutral compound
has been reported in the literature.[42]

1-(4-Aminobenzyl)-2-methyl-1H-imidazol-3-ium (22)
1
Brown solid, 0.84 g (80 %). H NMR (300 MHz, DMSO-d6): δ 8.23 (2H, d, J=8.5 Hz,
Ph-H), 7.75 (1H, d, J=2.0 Hz, NHCHCHN), 7.61 (1H, d, J=2.0 Hz, NHCHCHN), 7.56
(2H, d, J=8.7 Hz, Ph-H), 5.60 (2H, s, CH2), 2.59 (3H, s, CH3).13C NMR (75 MHz, DMSO-
d6): δ 147.3 (Ar-C), 144.6 (Ar-C), 142.2 (Ar-C), 128.9 (Ar-C), 124.0 (Ar-C), 122.3 (Ar-
C), 118.5 (Ar-C), 49.0 (CH2), 10.4 (CH3). HRMS calculated for C11H14N3 [M]+ 188.1188,
found 188.1193. m.p. 183-185 °C.
1-(5-Amino-2-chlorobenzyl)-1H-imidazol-3-ium (23)
1
Pale yellow solid, 1.06 g (92 %). H NMR (300 MHz, DMSO-d6): δ 9.35 (1H, t, J=1.3
Hz, NHCHN), 8.38 (1H, d, J=2.7 Hz, Ph-H), 8.28 (1H, dd, J=8.8, 2.8 Hz, Ph-H), 7.85
(1H, d, J=8.8 Hz, Ph-H), 7.80 (1H, t, J=1.7 Hz, NHCHCHN), 7.74 (1H, t, J=1.7 Hz,
NHCHCHN), 5.71 (2H, s, CH2). 13C NMR (75 MHz, DMSO-d6): δ 146.6 (Ar-C), 140.1
(Ar-C), 136.1 (Ar-C), 134.0 (Ar-C), 131.3 (Ar-C), 126.2 (Ar-C), 125.6 (Ar-C), 122.3 (Ar-
C), 120.2 (Ar-C), 49.2 (CH2). HRMS calculated for C10H11ClN3 [M]+ 208.0642, found
208.0645. m.p. 233-234 °C.
1-(5-Amino-2-chlorobenzyl)-2-methyl-1H-imidazol-3-ium (24)
1
Black solid, 1.12 g (92 %). H NMR (400 MHz, DMSO-d6): δ 8.26 (1H, dd, J=8.8, 2.8
Hz, Ph-H), 8.11 (1H, d, J=2.7 Hz, Ph-H), 7.87 (1H, t, J=8.8 Hz, Ph-H), 7.64 (1H, d, J=2.0
Hz, NHCHCHN), 7.58 (1H, d, J=2.0 Hz, NHCHCHN), 5.60 (2H, s, CH2), 2.66 (3H, s,

CH3). 13C NMR (100 MHz, DMSO-d6): δ 146.7 (Ar-C), 145.2 (Ar-C), 139.7 (Ar-C), 133.7
(Ar-C), 131.4 (Ar-C), 125.3 (Ar-C), 125.3 (Ar-C), 122.2 (Ar-C), 118.4 (Ar-C), 47.7
(CH2), 10.6 (CH3). HRMS calculated for C11H13ClN3 [M]+ 222.0798, found 222.0799.
m.p. 199-201 °C.
4-((1H-imidazol-1-yl)methyl)phenol (25)
1
Pale brown solid, 1.12 g (80%). H NMR (400 MHz, DMSO-d6): δ 9.47 (1H, bs, OH),
7.68 (1H, s, NCHN), 7.10-7.01 (3H, m, Ph-H & NCHCHNCH2), 6.86 (1H, t, J=1.0 Hz,
NCHCHNCH2), 6.71 (2H, d, J=8.5 Hz, Ph-H), 5.02 (2H, s, CH2). 13C NMR (100 MHz,
DMSO-d6): δ 157.0 (Ar-C), 137.1 (Ar-C), 129.1 (Ar-C), 128.5 (Ar-C), 127.9 (Ar-C),
119.3 (Ar-C), 115.3 (Ar-C), 49.1 (CH2). HRMS calculated for C10H10N2NaO [M+Na]+
197.0685, found 197.0689. m.p. 210-212 °C (lit. m.p. 210-211 °C). The NMR spectra are
in agreement with the literature.[52]
4-((2-Methyl-1H-imidazol-1-yl)methyl)phenol (26)
1
Brown solid, 1.25 g (90%). H NMR (300 MHz, DMSO-d6): δ 9.46 (1H, bs, OH), 7.05
(1H, d, J=1.3 Hz, NCHCHNCH2), 6.99 (2H, d, J=8.6 Hz, Ph-H), 6.75-6.68 (3H, m, Ph-
H & NCHCHNCH2), 4.97 (2H, s, CH2), 2.22 (3H, s, CH3). 13C NMR (75 MHz, DMSO-
d6): δ 156.8 (Ar-C), 143.6 (Ar-C), 128.6 (Ar-C), 127.6 (Ar-C), 126.2 (Ar-C), 120.0 (Ar-
C), 115.4 (Ar-C), 48.3 (CH2), 12.8 (CH3). HRMS calculated for C11H13N2O [M+H]+

189.1022, found 189.1022. m.p. 209-210 °C. The NMR spectra are in agreement with the
literature.[52]
Acknowledgements
We gratefully acknowledge the assistance of Dr. Waleed Hussein, Professor Gerhard
Schenk and Associate Professor Ross McGeary at the University of Queensland.

References
[1] O. Khalili Arjomandi, M. Kavoosi, H. Adibi, Synthesis and enzyme-based evaluation of analogues L-tyrosine
thiol carboxylic acid inhibitor of metallo-β-lactamase IMP-1, J. Enzyme Inhib. Med. Chem. 34(1) (2019) 1414-
1425.
[2] O. Khalili Arjomandi, W.M. Hussein, P. Vella, Y. Yusof, H.E. Sidjabat, G. Schenk, R.P. McGeary, Design,
synthesis, and in vitro and biological evaluation of potent amino acid-derived thiol inhibitors of the metallo-β-
lactamase IMP-1, Eur. J. Med. Chem. 114 (2016) 318-327.
[3] Y. Yusof, D.T. Tan, O.K. Arjomandi, G. Schenk, R.P. McGeary, Captopril analogues as metallo-β-lactamase
inhibitors, Bioorg. Med. Chem. Lett. 26(6) (2016) 1589-1593.
[4] R.P. McGeary, D.T. Tan, G. Schenk, Progress toward inhibitors of metallo-β-lactamases, Future Med. Chem.
9(7) (2017) 673-691.
[5] D. King, N. Strynadka, Crystal structure of New Delhi metallo-β-lactamase reveals molecular basis for
antibiotic resistance, Protein Science 20(9) (2011) 1484-1491.
[6] J.-D. Docquier, S. Mangani, An update on β-lactamase inhibitor discovery and development, Drug. Resist.
Update 36 (2018) 13-29.
[7] M. Everett, N. Sprynski, A. Coelho, J. Castandet, M. Bayet, J. Bougnon, C. Lozano, D.T. Davies, S. Leiris, M.
Zalacain, I. Morrissey, S. Magnet, K. Holden, P. Warn, F. De Luca, J.-D. Docquier, M. Lemonnier, Discovery of a
Novel Metallo-β-Lactamase Inhibitor That Potentiates Meropenem Activity against Carbapenem-Resistant
Enterobacteriaceae Antimicrob. Agents Chemother. 62(5) (2018) e00074-18.
[8] C. Shi, J. Chen, X. Kang, X. Shen, X. Lao, H. Zheng, Approaches for the discovery of metallo-β-Lactamase
inhibitors: a review, Chem. Biol. Drug Des. (2019).
[9] M. Everett, N. Sprynski, A. Coelho, J. Castandet, M. Bayet, J. Bougnon, C. Lozano, D.T. Davies, S. Leiris, M.
Zalacain, I. Morrissey, S. Magnet, K. Holden, P. Warn, F. De Luca, J.-D. Docquier, M. Lemonnier, Discovery of a
Novel Metallo-β-Lactamase Inhibitor That Potentiates Meropenem Activity against Carbapenem-Resistant <span
class="named-content genus-species" id="named-content-1">Enterobacteriaceae</span>, 62(5) (2018) e00074-
18.
[10] M.I. Page, A. Badarau, The mechanisms of catalysis by metallo beta-lactamases, Bioinorg. Chem. Appl. 2008
(2008).
[11] N. Díaz, D. Suárez, K.M. Merz, Zinc metallo-β-lactamase from Bacteroides fragilis: A quantum chemical study
on model systems of the active site, J. Am. Chem. Soc. 122(17) (2000) 4197-4208.
[12] C. Bebrone, Metallo-β-lactamases (classification, activity, genetic organization, structure, zinc coordination)
and their superfamily, Biochem. Pharmacol. 74(12) (2007) 1686-1701.
[13] M.W. Crowder, J. Spencer, A.J. Vila, Metallo-β-lactamases: Novel weaponry for antibiotic resistance in
bacteria, Acc. Chem. Res. 39 (2006) 721-728.
[14] J. Moran-Barrio, J.M. Gonzalez, M.N. Lisa, A.L. Costello, P.M. Dal, P. Carloni, B. Bennett, D.L. Tierney, A.S.
Limansky, A.M. Viale, A.J. Vila, The metallo-β-lactamase GOB is a mono-zn(ii) enzyme with a novel active site, J.
Biol. Chem. 282(25) (2007) 18286-18293.
[15] R. Paul-Soto, R. Bauer, J.-M. Frere, M. Galleni, W. Mayer-Klaucke, H. Nolting, G.M. Rossolini, S.D. de, M.
Hernandez-Valladares, M. Zeppezauer, H.-W. Adolph, Mono- and binuclear Zn2+-β-lactamase. Role of the
conserved cysteine in the catalytic mechanism, J. Biol. Chem. 274(19) (1999) 13242-13249.
[16] E.K. Phelan, M. Miraula, C. Selleck, D.L. Ollis, G. Schenk, N. Mitić, Metallo-β-lactamases: a major threat to
human health, J. Mol. Biol. 4(03) (2014) 11-15.
[17] M. Galleni, J. Lamotte-Brasseur, G.M. Rossolini, J. Spencer, O. Dideberg, J.-M. Frère, Standard numbering
scheme for class B β-lactamases, Antimicrob. Agents Chemother. 45(3) (2001) 660-663.
[18] B.M.R. Lienard, C. Papamicael, C.J. Schofield, G. Garau, O. Dideberg, L. Horsfall, P. Lassaux, M. Galleni, J.-M.
Frere, A.I. Karsisiotis, C. Damblon, G.C.K. Roberts, Structural basis for the broad-spectrum inhibition of metallo-
beta-lactamases by thiols, Org. Biomol. Chem. 6(13) (2008) 2282 - 2294.
[19] T. Palzkill, Metallo-β-lactamase structure and function, Ann N.Y. Acad Sci 1277(1) (2013) 91-104.