meta-Cyanobenzyl substituted benzimidazolium salts: Synthesis, characterization, crystal structure and carbonic anhydrase, α-glycosidase, butyrylcholinesterase, and acetylcholinesterase inhibitory properties

Article abstract of DOI:10.1002/ardp.201800029

meta-Cyanobenzyl-substituted N-heterocyclic carbene (NHC) precursors were synthesized by the reaction of a series of N-(alkyl)benzimidazolium with 3-bromomethyl-benzonitrile. These benzimidazolium salts were characterized by using ¹H NMR, ¹³C NMR, FTIR spectroscopy, and elemental analysis techniques. The molecular and crystal structures of 2f and 2g complexes were obtained by using the single-crystal X-ray diffraction method. The derivatives of these novel NHC precursors were effective inhibitors of α-glycosidase (AG), the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) with K_i values in the range of 1.01–2.12 nM for AG, 189.56–402.44 nM for hCA I, 112.50–277.37 nM for hCA II, 95.45–352.58 nM for AChE, and 132.91–571.18 nM for BChE. In the last years, inhibition of the CA enzyme has been considered as a promising factor for pharmacologic intervention in a diversity of disturbances such as obesity, glaucoma, cancer, and epilepsy.

Full text of DOI:10.1002/ardp.201800029

Received: 7 February 2018
Revised: 18 April 2018
Accepted: 24 April 2018
|
|
DOI: 10.1002/ardp.201800029
FULL PAPER
meta-Cyanobenzyl substituted benzimidazolium salts:
Synthesis, characterization, crystal structure and carbonic
anhydrase, α-glycosidase, butyrylcholinesterase, and
acetylcholinesterase inhibitory properties
Ferhat Türker1
Duygu Barut Celepci2
Aydın Aktaş1
Parham Taslimi3
|
|
|
|
Yetkin Gök1
Muhittin Aygün2
İlhami Gülçin3
|
|
1 Faculty of Arts and Sciences, Department of
Chemistry, Inönü University, Malatya, Turkey
Abstract
2 Faculty of Science, Department of Physics,
meta-Cyanobenzyl-substituted N-heterocyclic carbene (NHC) precursors were synthe-
sized by the reaction of a series of N-(alkyl)benzimidazolium with 3-bromomethyl-
benzonitrile. These benzimidazolium salts were characterized by using 1HNMR,13CNMR,
FTIR spectroscopy, and elemental analysis techniques. The molecular and crystal
structures of 2f and 2g complexes were obtained by using the single-crystal X-ray
diffraction method. The derivatives of these novel NHC precursors were effective
inhibitors of α-glycosidase (AG), the cytosolic carbonic anhydrase I and II isoforms (hCA I
and II), butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) with Ki values in the
range of 1.01–2.12 nM for AG, 189.56–402.44 nM for hCA I, 112.50–277.37 nM for hCA
II, 95.45–352.58 nM for AChE, and 132.91–571.18 nM for BChE. In the last years,
inhibition of the CA enzyme has been considered as a promising factor for pharmacologic
intervention in a diversity of disturbances such as obesity, glaucoma, cancer, and epilepsy.
Dokuz Eylül University, Buca, İzmir, Turkey
3 Faculty of Science, Department of
Chemistry, Ataturk University, Erzurum,
Turkey
Correspondence
Dr. Parham Taslimi, Faculty of Science,
Department of Chemistry, Ataturk University,
25240-Erzurum, Turkey.
Email: parham_taslimi_un@yahoo.com,
parhamsmkh66@gmail.com
Funding information
Dokuz Eylul University, Grant number: 2010.
KB.FEN.13
K E Y W O R D S
α-glycosidase, acetylcholinesterase, butyrylcholinesterase, carbonic anhydrase, enzyme
inhibition, N-heterocyclic carbene precursors
|
1
INTRODUCTION
metal-NHC complexes, it is observed that the molecules with bulky
and lipophilic properties exhibit higher biological activity.[11,12] In
N-Heterocyclic carbene (NHC) precursors have drawn considerable
attention in organometallic chemistry.[1] Especially, numerous studies
have been carried out on the catalytic activities of metal-NHC
complexes.[2–4] Furthermore, there have been numerous studies on
the medical applications of metal-NHCs for the past two decades.[5–8]
The chelating effect of NHC precursors with unique sigma donor
properties has recently attracted the attention of organometallic
chemists. This effect could be effective on biological activity.[9,10]
In the studies of biological activity related to NHC precursor and
recent years, because of their great structural diversity and multitude
of chemical properties, NHCs have been utilized in a variety of
capacities. Most recently, NHCs have been utilized as carrier molecules
for many transition metals in medicinal chemistry. Specifically, Ag+-
NHCs have been investigated as potent antibacterial agents and
chemotherapeutics and have shown great efficacy in both in vitro and
in vivo studies.[13,14] Hence we speculated that NHC precursors had
the positive charge and linked to the both CA isoenzymes active sides
and realized their inhibition effects in these forms.
|
Arch Pharm Chem Life Sci. 2018;e1800029.
wileyonlinelibrary.com/journal/ardp
© 2018 Deutsche Pharmazeutische Gesellschaft
1 of 11
https://doi.org/10.1002/ardp.201800029

2 of 11
TÜRKER ET AL.
|
Carbonic anhydrase isoenzymes (CAs) as zinc metalloenzymes are
present in many tissues.[15,16] They catalyze the reversible hydration of
water and carbon dioxide to a proton ion and bicarbonate.[17,18] Until now,
human cells express 12 catalytically active CA isoenzymes belonging to
the class.[19–21] These isoenzymes have been classified into four disparate
subclasses based on the subcellular mechanism: secreted (CA VI),
cytosolic isoforms (CAs I–III, VII, and XIII), mitochondrial (CAs VA and
VB) and membrane-bound (CAs IV, IX, XII, and XIV) forms.[22–26]
Additionally, they also have tissue distributions and catalytic
activities.[27–29] These isoenzymes play a fundamental role in crucial
physiological mechanisms relevant to electrolyte secretion in a variety of
tissues/organs, acid-base regulation and respiration, and biosynthetic
reactions including ureagenesis, gluconeogenesis, and lipogenesis.[30,31]
The acetylcholinesterase (AChE, E.C.3.1.1.7) enzyme is a particular
esterase that belongs to the carboxyl esterase class of enzymes.[32,33] It
mostly hydrolyzes the neurotransmitter acetylcholine (ACh). This enzyme is
found in high concentrations predominantly in the erythrocyte or red blood
cells as well as in the brain cells at cholinergic brain synapses and
neuromuscular junctions.[34–37] Additionally, the enzyme butyrylcholinester-
ase (BChE) which is considered as pseudo cholinesterase (ChE, E.C.3.1.1.8) is
a non-specific kind of ChE that hydrolyzes several kinds of ChEs and it
ubiquitously exists all over the human body, especially, in the blood serum,
human liver, the central neural system, and pancreas.[38,39] In the brain cells,
BChE is essentially associated with endothelial cells and glial cells.[40]
Diabetes mellitus(DM) is achronic disturbance of metabolism caused by
arelativeorabsolutelackofinsulin.[41,42] It is determined by hyperglycemia in
fasting state and postprandial, and its intense form is associated with protein
wasting and ketosis.[43] Enhanced postprandial hyperglycemia (PPHG) is one
of the danger agents. PPHG is investigated by the act of α-amylase and
α-glycosidase (AG).[44] Inhibition of these metabolic enzymes plays an
important role in managing PPHG factors in diabetic patients. Inhibition
of AG enzyme gives rise to a diminution in disaccharide hydrolysis, which
has useful effects on glycemic index control in diabetic patients.[45]
The studiesonthe biological activityofNHCcompoundscontaining
cyanobenzyl substituents show that these compounds have exhibited
biological activity.[11] In this study, we have performed the facile
synthesis of well-defined meta-cyanobenzyl-substituted NHC precur-
sors (1 and 2a–g). The molecular and crystal structure of meta-
cyanobenzyl 2f and 2g were established through single-crystal X-ray
diffraction methods. In addition to this study, we have investigated their
inhibition potential of hCA I and II isoenzymes, and to discover the most
favorable and potent AChE, BChE, and AG inhibition properties of these
compounds to give directions to further studies.
(Schemes 1 and 2). The effects on enzyme inhibition studies of
electronic and steric properties of the meta-cyanobenzyl-substituted
benzimidazolium salts have been researched. These salts 2a–g were
prepared by mixing 1-aryl-1H-benzoimidazole with 1 equivalent of
3-bromomethyl-benzonitrile at 70–110°C for 24 h and were
obtained as a white solid in between 81 and 87% yield. All the air
and moisture stable benzimidazolium salts were soluble in polar
solvents such as water, dimethylsulfoxide, and dimethylformamide.
The formation of the new meta-cyanobenzyl-substituted benzimi-
dazolium salts was confirmed by FT-IR, 1H NMR and 13C NMR
spectroscopic methods, and elemental analysis techniques. These
spectra are consistent with the proposed formulate. In the 1H NMR
spectra, a characteristic proton peak at the 2-position (NCHN) of the
meta-cyanobenzyl-substituted benzimidazolium salts 2a–g was
detected, which appeared as highly downfield shifted singlets at δ
10.32, 10.01, 10.13, 10.10, 9.47, 9.42, and 9.34 ppm in the 1H NMR
spectra, respectively. The NCHN carbon resonances of meta-
cyanobenzyl-substituted benzimidazolium salts 2a–g in the
13C NMR spectra appeared highly downfield
δ 143.5, 143.7,
143.6, 143.5, 142.3, 142.2, and 142.1 ppm in the 13C NMR spectra.
The results of the elemental analysis, in which one of the analytical
techniques was used to prove the synthesis of compounds, then the
results were evaluated and it was observed that the calculated
values were very close to the found values. The FT-IR data clearly

indicated the presence of ν(C N benzimidazole) 1559, 1563, 1557,
1558, 1553, 1563, and 1560 cm−1 for the benzimidazolium salts
(2a–g) proved, respectively. The FT-IR data clearly indicated the

presence of ν(C N benzonitrile), 2225, 2224, 2227, 2230, 2238,
2228, 2229 cm−1 for the benzonitrile group proved, respectively.
Also, we obtained single crystal for meta-cyanobenzyl-substituted
benzimidazolium salts 2f and 2g with X-ray diffraction method.
|
2.2 Enzyme inhibition results
All the synthesized molecules (novel NHC precursor's derivatives (1
and 2a–g)) were tested to investigate their inhibitory activity toward
the slower cytosolic isoform (hCA I), the more rapid cytosolic
isoenzyme (hCA II), AG, AChE, and BChE enzymes. The chemical
formula of meta-cyanobenzyl-substituted benzimidazolium salts (1 and
2a–g) is given in Scheme 1 and their AChE, BChE, AG, and CA I and II
isoforms inhibition data are summarized in Table 1. Novel NHC
precursor's derivatives (1 and 2a–g) showed effective inhibition
|
2
RESULTS AND DISCUSSION
|
2.1 Chemistry
|
2.1.1 Synthesis of the meta-cyanobenzyl-substituted
benzimidazole and benzimidazolium salts (1, 2a–g)
A series of meta-cyanobenzyl-substituted benzimidazole 1 and
benzimidazolium salts 2a–g has been synthesized successfully
SCHEME 1 Synthesis of meta-cyanobenzyl-substituted
benzimidazolium salts 1

TÜRKER ET AL.
3 of 11
|
SCHEME 2 Synthesis of meta-cyanobenzyl-substituted benzimidazolium salts 2a–g
profiles against the enzymes mentioned above. The following results
are presented in Table 1:
new molecules had Ki values ranging from 95.45 8.03 to
352.58 43.12 nM for AChE and 132.91 45.53 to
571.18 119.58 nM for BChE. Additionally, tacrine (TAC) com-
pound, used as standard inhibitor, had Ki values of
87.21 14.42 nM toward AChE and 58.36 13.06 nM toward
BChE. In this work, all the evaluated novel NHC precursor's
derivatives (1 and 2a–g) showed potent inhibition against AChE
and BChE enzymes, but the compound of 1-(3-cyano-benzyl)-3-
(2,4,6-trimethyl-benzyl)-3H-benzoimidazol-1-ium bromide, 2e, for
AChE and the compound of 1-(3-cyano-benzyl)-3-(4-methyl-
benzyl)-3H-benzoimidazol-1-ium bromide, 2d, for BChE showed
excellent inhibition profile against AChE and BChE with Ki values of
95.45 8.03 and 132.91 45.53 nM, respectively (Figure 2).
(4) For the AG enzyme, the novel NHC precursor's derivatives (1 and
2a–g) had IC50 values in the range of 1.45–2.38 and Ki values in the
range of 1.01 0.28–2.12 0.37 nM (Table 1 and Figure 1). The
results obviously showed that all novel NHC precursor derivatives
(1 and 2a–g) demonstrated efficient AG inhibitory effects than that
of acarbose (IC50: 22800 nM) as standard AG inhibitor. However,
the most effective Ki values were obtained by 1-(3-cyano-benzyl)-
3-(4-methyl-benzyl)-3H-benzoimidazol-1-ium bromide, 2d, and
1-(3-cyano-benzyl)-3-(2,3,4,5,6-pentamethyl-benzyl)-3H-benzo-
imidazol-1-ium bromide, 2g, with Ki values of 1.18 0.51 and
1.01 0.28 nM, respectively.
(1) Cytosolic hCA I and II both existed in erythrocyte cells, which are
indispensable items for regulating the physiological pH of the
blood via manufacturing of HCO3 .
− [46] The cytosolic enzyme hCA I
was inhibited by the novel NHC precursor's derivatives (1, 2a–g),
with Ki values ranging between 189.56 29.63 and
402.44 97.87 nM. In addition, 1-(3-cyano-benzyl)-3-(2,3,5,6-
tetramethyl-benzyl)-3H-benzoimidazol-1-ium bromide, 2f re-
corded the most powerful hCA I isoform inhibition properties
with a Ki value of 189.56 29.63 nM. The clinically and standard
used drug acetazolamide (AZA) calculated
a Ki value of
501.17 44.17 nM. Thus, the evaluated novel NHC precursor's
derivatives (1 and 2a–g) showed better inhibitory profiles when
compared to AZA molecule (Table 1 and Figure 1).
(2) HCA II has been dependent on various transporters including the Na+/
H+ exchanger, the Cl−/HCO3 exchanger, and the Na+/HCO3
−
−
cotransporter.[47] Indeed, hCA II enzyme is mostly associated with
multiple diseases such as glaucoma, renal tubular acidosis, and
osteoporosis. It is most largely characterized and studied by the CA
isoenzymes.[48] The hCA II was impressively inhibited by the novel
NHC precursor's derivatives (1 and 2a–g) evaluated here. These
molecules shown to strongly inhibit hCA II, with Ki values ranging from
112.50 22.20 to 277.37 64.23 nM. Ki amounts of newly molecules
are better than those of the standard used drug AZA (Ki:
382.15 78.11 nM). All the evaluated novel NHC precursor's
derivatives (1 and 2a–g) showed potent inhibition against hCA II,
but the compound of 1-(3-cyano-benzyl)-3-(2,3,4,5,6-pentamethyl-
benzyl)-3H-benzoimidazol-1-ium bromide, 2g, showed an significant
inhibition profile against hCA II with a Ki value of 112.50 22.20 nM
(Table 1, Figures 1 and 2).
DM, one of the most prevalent metabolic diseases, is resulting
from a shortage in insulin amounts.[49] Type 2 diabetes is considered by
hyperglycemia due to defects in insulin action, secretion, or both and
has rapidly become a mental and physical burden that diminishes the
quality of human life and results in high rates of disability and
mortality.[50] Equilibration of postprandial blood glucose amounts is
absolutely important, since postprandial hyperglycemia is character-
ized more hazardous than fasting blood glucose.[51] AG enzyme can
release glucose molecule by hydrolyzing branched and linear
(3) AChE and BChE were very strongly inhibited by novel NHC
precursor's derivatives (1 and 2a–g) (Table 1 and Figure 1). These

4 of 11
TÜRKER ET AL.
|
FIGURE 1 (A) IC50 values for hCA I and hCA II isoenzymes,
AChE, and BChE enzymes. (B) Ki values for hCA I and hCA II
isoenzymes, AChE, and BChE enzymes. (C) IC50 and Ki values for
α-glycosidase
isomaltose polysaccharides, giving rise to postprandial hyperglycemia.
Thus, characterizing and identifying the inhibitors of AG that can be
utilized therapeutically is momentous.[52] Commercial AG such as
voglibose and acarbose have been used to therapy diabetes, but they
exhibit side effects, like acute hepatitis, liver disorders, abdominal

TÜRKER ET AL.
5 of 11
|
FIGURE 2 Ki graphs of the best inhibitors: (1) hCA I (2f), (2) hCA II (2g), (3) AChE (2e), (4) BChE (2d), (5) α-glycosidase (2g)
fullness, flatulence, abdominal pain, hepatic injury, renal tumors, and
diarrhea.[53]
significantly higher.[56] The acetylcholinesterase inhibitor (AChEI)
therapy recorded betterments in the cognitive, functional, and
behavioral symptoms related to hypocholinergic states, demonstrated
especially by the AD. Many clinical tests using AChEIs for the therapy
of AD have been performed. Tacrine compound was the first drug to
be trialed and also clinically utilized.[57]
Recently, a large deal of consideration has been recorded to
natural extracts exhibiting AG behaviors, such as those from germ and
wheat bran, guava leaves, and grape skins. Several studies have
recorded that inflammatory pathways have a significant role linking
neurodegenerative diseases such as Alzheimer's disease (AD) and
T2DM.[54] However, it has been noted that tissue levels of AChE and
BChE and altered plasma can also serve as markers for the entity of
slight-grade systemic inflammation in disturbances such as AD and
T2DM.[55] Actually, it has been considered that activities of BChE and
AChE are elevated in diseases like AD and T2DM including interleukin-
6, slight-grade systemic inflammation even when plasma, tissue
concentrations and cerebrospinal fluid of C-reactive protein, tumor
necrosis factor (TNF-α) and other markers of inflammation are not
For hCA I isoenzyme (generally considered a significant isoenzyme
when CAIs for antiglaucoma or anticancer activity are encountered)
was well inhibited by all of the investigated molecules, the best
inhibitors of them were 1-(3-cyano-benzyl)-3-(2,3,5,6-tetramethyl-
benzyl)-3H-benzoimidazol-1-ium bromide, 2f, 1-(3-cyano-benzyl)-3-
(2,3,4,5,6-pentamethyl-benzyl)-3H-benzoimidazol-1-ium bromide, 2g
(Figure 1). The 3-benzyl-1-(3-cyano-benzyl)-3H-benzoimidazol-1-ium
bromide, 2a, and 1-(3-cyano-benzyl)-3-(4-methyl-benzyl)-3H-benzo-
imidazol-1-ium bromide, 2d, compounds are weaker inhibitors

6 of 11
TÜRKER ET AL.
|
compared to other molecules for this isoenzyme. The compound 2f
was shown to have the excellent inhibitory effect on hCA I isoform
activity while the compound 2g was shown to have the excellent
inhibitory effect on hCA I isoform activity. For hCA II isoform, the best
inhibitors of them were 1-(3-cyano-benzyl)-3-(3-methyl-benzyl)-3H-
benzoimidazol-1-ium bromide, 2c, and 1-(3-cyano-benzyl)-3-
(2,3,4,5,6-pentamethyl-benzyl)-3H-benzoimidazol-1-ium
bromide,
2g. The 3-benzyl-1-(3-cyano-benzyl)-3H-benzoimidazol-1-ium bro-
mide, 2a, compound is weak inhibitor compared with other compounds
for hCA II isoenzyme. As seen in Table 1 and Figure 1, IC50 values are in
the range of 171.83–250.18 nM toward hCA II, while for hCA I is in the
range of 270.17–359.62 nM, and also IC50 values for AChE is in the
range of 185.04–375.40 nM, while for BChE is in the range of 240.21–
669.56. The IC50 values for standard molecule AZA toward hCA II and I
are 418.22 and 534.88 nM, respectively. All molecules have lower IC50
value compared with AZA toward hCA II and hCA I isoenzymes.
CA enzyme reaction is involved in many pathological and
physiological processes such as transport of bicarbonate and CO2
between metabolism lungs and tissues.[58] Examples are electrolyte
secretion in various tissues and organs, pH and CO2 homeostasis,
lipogenesis and ureagenesis, glyconeogenesis, calcification, osteocla-
sis, and tumorigenicity.[59] These mechanisms include CA isoforms that
serve as therapeutic aims prone to be inhibited to therapy diverse
disturbances such as glaucoma, edema, cancer, obesity, osteoporosis,
and epilepsy.[60] CA inhibitors (CAIs) have been utilized clinically as
diuretic, antiglaucoma, anti-infective, antiobesity drugs, and anticon-
vulsant drugs, whereas their functions were only recently recorded in
the treatment of hypoxic tumor or cancers. CAIs are a class of
chemicals or pharmaceuticals that suppress the CA activity.[61]
FIGURE 3 The structure of 2f. Displacement ellipsoids are drawn
at the 25% probability level. Selected bond distances (Å) and angles
(°): N1-C1 1.3246(1), N1-C2 1.3994(1), N1-C8 1.4575(1), N2-C1
1.3206(1), N2-C7 1.3911(1), N2-C16 1.4720(1), N3-C15 1.1419(1);
N1-C1-N2 110.48(3), C1-N1-C8 125.63(3), C1-N2-C16 126.08(3),
N1-C8-C9 115.51(3), N2-C16-C17 112.37(3), N3-C15-C11 178.38
(3); N1-C8-C9-C10 1.13(3), C1-N2-C16-C17 39.48(3), N1-C8-C9-
C14 −178.61(3)
bonds involving bromide anion and cyano nitrile. Bromide anions act as
an acceptor and link the molecules with C8-H8A · · · Br12i to form a
R24ð8Þ graph-set notation. Molecules are also linked by pairs of
C10─H10 · · · N32ii hydrogen bonds forming
a dimer with the
R22ð10Þ graph-set motif. Through these interactions and with the
C26─H26B · · · Br12iii hydrogen bond, the crystal structure forms a
three-dimensional network, which is shown in Figure 5.
|
2.3 Crystal structures
The molecular structures of the compounds 2f and 2g are shown in
Figures 3 and 4. Crystallographic data and refinement details are
tabulated in Table 2. The asymmetric units of the compounds are
composed of meta-cyanobenzyl-substituted benzimidazolium. In 2f, a
tetramethyl-benzyl groupisconnected tothe benzimidazole, whereasin
2g, a pentamethyl-benzyl group is connected to this moiety. The single
crystal X-ray diffraction studies of the compound 2f indicate that the
benzimidazole ring system issubstantiallyplanar with the r.m.sdeviation
of 0.007 Å, and forms dihedral angles of 70.28 (2)° and 101.87 (2)° with
the mean plane through the cyanobenzyl and tetramethyl-benzyl rings,
respectively. Similarly, the compound 2g has almost planar benzimid-
azole ring system with the r.m.s deviation of 0.012. It also forms dihedral
angles of 111.76 (1)° and 70.235 (2)° with the mean plane through the
cyanobenzyl and pentamethyl-benzyl rings, respectively. The N─C
bond lengths for both compounds are complying with the values of
similar cyanobenzyl-substituted benzimidazolium salts.[62,63]
FIGURE 4 The structure of 2g. Displacement ellipsoids are
drawn at the 25% probability level. Selected bond distances (Å),
bond angles and torsion angles (°): N1-C1 1.337(2), N1-C2 1.379(2),
N1-C8 1.479(2), N2-C1 1.327(2), N2-C7 1.380(2), N2-C16 1.490(2),
N3-C15 1.137(2); N1-C1-N2 109.8(7), C1-N1-C8 124.6(7), C1-N2-
C16 125.8(7), N1-C8-C9 113.2(7), N2-C16-C17 114.2(7), N3-C15-
C11 178.6(2); N1-C8-C9-C10 81.3(9), C1-N2-C16-C17 45.7(2), N1-
C8-C9-C14 −99.1(9)
In 2f, two intermolecular hydrogen bonds are observed between
the carbon atoms of benzimidazolium and the bromide anion:
C1-H1 · · · Br1i and C4-H4 · · · Br1ii. Molecules propagate one-
dimensional infinite chain along the b-axis via these hydrogen bonds
(Figure 5). The crystal structure of the 2g is dominated by hydrogen

TÜRKER ET AL.
7 of 11
|
TABLE 2 Crystal data and structural refinement parameters
Compound
Formula
Mr (g/mol)
Crystal system
Space group
a (Å)
2f
2g
C
26H26BrN3
C27H28BrN3
474.43
460.41
Orthorhombic
Triclinic
P−1
P 21 21 21
6.3993(4)
8.761(3)
10.735(4)
12.848(5)
106.19(3)
90.62(3)
94.27(3)
1156.3(7)
2
b (Å)
12.5886(10)
c (Å)
27.767(2)
α (°)
90
β (°)
90
γ (°)
90
V (Å3)
2236.8(3)
Z
4
Dc (g/cm3)
1.367
1.363
µ (mm−1
)
1.855
1.797
F (000)
952
492
Crystal size (mm3)
0.348 × 0.214 × 0.096
7245
0.397 × 0.280 × 0.166
7144
Measured
reflections
Independent
reflections
3065
4327
GOOF
0.995
1.012
R indices obs.
R1 = 0.047
R1 = 0.088
data
wR2 = 0.072
wR2 = 0.151
R indices all data
R1 = 0.079
R1 = 0.234
wR2 = 0.082
wR2 = 0.203
FIGURE 5 (Top) Packing view for the 2f showing the
intermolecular hydrogen bonds C1-H1 · · · Br1i [H1 · · · Br1 2.72 Å,
C1-Br1 3.604(3) Å, C1-H1 · · · Br1 158°, symmetry code: (i) 1 + x, y,
z], C4-H4 · · · Br1ii [H4 · · · Br1 2.75 Å, C4-Br1 3.631(3) Å, C4-
H4 · · · Br1 158°, symmetry code: (ii) −x, 1/2 + y, 1/2 − z]. (Bottom)
Packing view for the 2g showing the intermolecular hydrogen
bonds C8-H8A · · · Br12i [H8A · · · Br1 2.74 Å, C1-Br1 3.698(9) Å,
C8-H8A · · · Br1 173°, symmetry code: (2i) −x, 1 − y, 2 − z],
C10-H10 · · · N32ii [H10 · · · N3 2.57 Å, C10-N3 3.443(2) Å,
C10-H10 · · · N3 156°, symmetry code: (2ii) −x, 1 − y, 1 − z] and
C26-H26B · · · Br12iii [H26B · · · Br1 2.93 Å, C26-Br1 3.807(2) Å,
C26-H26B · · · Br1 153°, symmetry code: (2iii) −x, −y, 1 − z]
|
3
CONCLUSIONS
As a result, this study contains the synthesis of the new meta-
cyanobenzyl-substituted benzimidazolium salts. Also, all of com-
pounds of synthesized have been characterized by using 1H NMR,
13C NMR, FTIR spectroscopy, and elemental analysis techniques. All of
the synthesized molecules effectively inhibited some metabolic
enzymes such as hCA I, and hCA II, AG, AChE, and BChE enzymes
at the nanomolar levels. As we characterized above, novel NHC
precursor derivatives (1 and 2a–g) can be acceptable candidate drugs,
the same as CAIs, for therapy of some diseases such as glaucoma,
epilepsy, gastric and duodenal ulcers, osteoporosis, mountain sickness,
or neurological disturbances. On the other hand, DM is a metabolic
difficulty created by high blood glucose content and can reason other
health disturbances, such as neuropathy, weakness, nephropathy
retinopathy, high blood pressure, cardiovascular disease, gangrene,
and other dysfunctions. Also, these novel compounds can be selective
inhibitor AChE, of AG, and BChE enzymes. Structural characterization
of the compounds 2f and 2g has also been done with single-crystal X-
ray diffraction method. Bromide anions have an important role for the
stabilization of the crystal structure of both compounds.
|
4
EXPERIMENTAL
|
4.1 Chemistry
|
4.1.1 General
All synthesis containing meta-cyanobenzyl-substituted 1a–f benzimi-
dazolium salts was performed in an inert atmosphere using standard
Schlenk techniques. The solvents commercially purchased were used
without exposure to any purification and drying process.

8 of 11
TÜRKER ET AL.
|
All other reagents were commercially available from Merck and
Aldrich Chemical Co. and were used without further purification.
Melting points were identified in glass capillaries under air with an
Electrothermal-9200 melting point apparatus. FT-IR spectra were
saved in the range 400–4000 cm−1 on Perkin Elmer Spectrum 100 FT-
IR spectrometer. Proton (1H) and carbon (13C) NMR spectra were
recorded using either a Bruker 400 Merkur spectrometer operating at
400 MHz (1H), 100 MHz (13C) in CDCl3 with tetramethylsilane as an
internal reference. Elemental analyses were performed by İnönü
University Scientific and Technology Centre (İBTAM) (Malatya,
Turkey).
Ar-H); 10.01 (s, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 19.4
(─CH2(C6H4)CH3); 49.1 (─CH2(C6H4)CN); 49.6 (─CH2(C6H4)CH3);
112.3, 114.5, 114.6, 118.9, 126.9, 127.4, 129.3, 129.1, 129.4,
130.7, 131.3, 132.5, 132.9, and 137.2. (Ar-C); 143.7 (2-CH).
|
4.1.5 Synthesis of 1-(3-cyanobenzyl)-3-(3-methyl-
benzyl)-3H-benzoimidazol-1-ium bromide 2c
The compound 2c was synthesized in the same method as that
described for 2a, but 1-(3-methyl-benzyl)-1H-benzoimidazole (1.55 g,
7 mmol) was used instead of 1-benzyl-1H-benzoimidazole. Yield:
The InChI codes of the investigated compounds together with
some biological activity data are provided as Supporting Information.
2.42 g (83%); m.p.: 210–211°C; ν(CN benzimidazole): 1557 cm−1
;
ν(C N benzonitrile): 2224 cm−1. Anal. calcd. for C23H20BrN3: C:
66.04, H: 4.82, N: 10.04. Found: C: 66.02, H: 4.84, N: 10.08. 1H NMR
(400 MHz, DMSO-d6), δ; 2.31 (s, 2H, ─CH2(C6H4)CH3); 5.77 (s, 2H,
─CH2(C6H4)CN); 5.89 (s, 2H, ─CH2(C6H4)CH3); 7.20–8.07 (m, 12H,
Ar-H); 10.13 (s, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 21.4
(─CH2(C6H4)CH3); 49.6 (─CH2(C6H4)CN); 50.6 (─CH2(C6H4)CH3);
112.4, 114.4, 114.6, 118.9, 126.0, 127.3, 127.4, 129.3, 129.4,
129.4, 130.7, 132.5, 133.0, and 133.8. (Ar-C); 143.6 (2-CH).

|
4.1.2 Synthesis of 3-benzoimidazol-1-ylmethyl-
benzonitrile 1
3-Benzoimidazol-1-ylmethyl-benzonitrile 1 was synthesized from the
reaction of benzimidazole (3 g, 25 mmol) and 3-bromomethyl-benzo-
nitrile (5 g, 25 mmol) as described in the literature.[64] This known
compound was synthesized and characterized by m.p., IR, 1H and
13C NMR, and microanalyses. Results, which we found, are consistent
with the literature.[65] Yield: 5.15 g (87%).
|
4.1.6 Synthesis of 1-(3-cyanobenzyl)-3-(4-methyl-
benzyl)-3H-benzoimidazol-1-ium bromide 2d
The compound 2d was synthesized in the same method as that
described for 2a, but 1-(4-methyl-benzyl)-1H-benzoimidazole (1.55 g,
|
4.1.3 Synthesis of 3-benzyl-1-(3-cyanobenzyl)-3H-
benzoimidazol-1-ium bromide 2a
7 mmol) was used instead of 1-benzyl-1H-benzoimidazole. Yield:
−1

2.52 g (86%); m.p.: 211–212°C; ν(C N benzimidazole): 1558 cm ;
The compound 2a was synthesized by the reaction of 3-bromomethyl-
benzonitrile (1.37 g, 7 mmol) and 1-benzyl-1H-benzoimidazole (1.46 g,
7 mmol) in DMF (4 mL). The reaction mixture was stirred for 20 h at
80°C and 2 h at 110°C temperatures. Then the solvents were
evaporated under vacuum to afford the product as a white solid.
The crude product was recrystallized from ethyl alcohol/diethyl ether
(1:3) at room temperature. Yield: 2.32 g (82%); m.p.: 213–214°C;
ν(C N benzonitrile): 2230 cm−1. Anal. calcd. for C23H20BrN3: C:
66.04, H: 4.82, N: 10.04. Found: C: 66.08, H: 4.84, N: 10.01. 1H NMR
(400 MHz, DMSO-d6), δ; 2.30 (s, 2H, ─CH2(C6H4)CH3); 5.75 (s, 2H,
─CH2(C6H4)CN); 5.88 (s, 2H, ─CH2(C6H4)CH3); 7.24–8.07 (m, 12H,
Ar-H); 10.10 (d, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 21.2
(─CH2(C6H4)CH3); 49.6 (─CH2(C6H4)CN); 50.5 (─CH2(C6H4)CH3);
112.4, 114.4, 114.6, 118.9, 127.3, 129.0, 130.0, 130.7, 131.6,
132.5, 133.0, 133.8, and 138.7. (Ar-C); 143.5 (2-CH).

−1
−1


ν(C N benzimidazole): 1559 cm ; ν(C N benzonitrile): 2225 cm
.
Anal. calcd. for C22H18BrN3: C: 65.36, H: 4.49, N: 10.39. Found: C:
65.41, H: 4.53, N: 10.37. 1H NMR (400 MHz, DMSO-d6), δ; 5.85 (s, 2H,
─CH2(C6H4)CN); 5.88 (s, 2H, ─CH2(C6H4)CH3); 7.42–8.16 (m, 12H,
Ar-H); 10.32 (s, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 50.3
(─CH2(C6H4)CN); 50.5 (─CH2(C6H4)CH3); 114.5, 127.3, 128.1, 128.9,
129.2, 129.5, 131.5, 134.5, and 135.5. (Ar-C); 143.5 (2-CH).
|
4.1.7 Synthesis of 1-(3-cyanobenzyl)-3-(2,4,6-
trimethyl-benzyl)-3H-benzoimidazol-1-ium bromide
2e
The compound 2e was synthesized in the same method as that
described for 2a, but 1-(2,4,6-trimethyl-benzyl)-1H-benzoimidazole
(1.75 g, 7 mmol) was used instead of 1-benzyl-1H-benzoimidazole.
Yield: 2.72 g (87%); m.p.: 268–269°C; ν(CN benzimidazole):
|
4.1.4 Synthesis of 1-(3-cyanobenzyl)-3-(2-methyl-
benzyl)-3H-benzoimidazol-1-ium bromide 2b
The compound 2b was synthesized in the same method as that
described for 2a, but 1-(2-methyl-benzyl)-1H-benzoimidazole (1.55 g,
7 mmol) was used instead of 1-benzyl-1H-benzoimidazole. Yield:
1553 cm−1
benzonitrile): 2238 cm−1

; ν(C N . Anal. calcd. for
C25H24BrN3: C: 67.27, H: 5.42, N: 9.41. Found: C: 67.24, H: 5.39, N:
9.44. 1H NMR (400 MHz, DMSO-d6), δ; 2.25 and 2.31 (s, 9H,
─CH2(C6H2)(CH3)3); 5.70 (s, 2H, ─CH2(C6H4)CN); 5.80 (s, 2H,
─CH2(C6H4)CH3); 7.06 (s, 2H, ─CH2(C6H2)(CH3)3); 7.61–8.17 (m,
8H, Ar-H); 9.47 (s, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 19.9
and 21.2 (─CH2(C6H2)(CH3)3); 45.8 (─CH2(C6H4)CH3); 49.5
(─CH2(C6H4)CN); 112.2, 114.4, 114.5, 118.9, 126.2, 127.2, 127.5,
2.49 g (85%); m.p.: 201–202°C; ν(CN benzimidazole): 1563 cm−1
;
ν(C N benzonitrile): 2227 cm−1. Anal. calcd. for C23H20BrN3: C:
66.04, H: 4.82, N: 10.04. Found: C: 66.11, H: 4.86, N: 10.02. 1H NMR
(400 MHz, DMSO-d6), δ; 2.38 (s, 2H, ─CH2(C6H4)CH3); 5.85 (s, 2H,
─CH2(C6H4)CN); 5.92 (s, 2H, ─CH2(C6H4)CH3); 7.25–8.09 (m, 12H,


TÜRKER ET AL.
9 of 11
|
130.0, 130.6, 131.5, 132.1, 132.4, 132.8, 133.3, 136.3, 139.0, and
were recorded during 3 min at 348 nm using p-nitrophenyl acetate as a
substrate which was converted by both isoenzymes to the p-
nitrophenolate ion compound.[73,74] For estimation of protein quantity,
the Bradford[75] way was used during the separation stages. The
presence and purity of both isoenzymes were recorded by the SDS–
PAGE method.[76]
139.37. (Ar-C); 142.3 (2-CH).
|
4.1.8 Synthesis of 1-(3-cyanobenzyl)-3-(2,3,5,6-
tetramethyl-benzyl)-3H-benzoimidazol-1-ium
bromide 2f
The compound 2f was synthesized in the same method as that
described for 2a, but 1-(2,3,5,6-tetramethyl-benzyl)-1H-benzoimida-
zole (1.85 g, 7 mmol) was used instead of 1-benzyl-1H-benzoimida-
|
4.2.2 AChE/BChE activity determination and
inhibition studies

zole. Yield: 2.61 g (81%); m.p.: 239–240°C; ν(C N benzimidazole):
The inhibitory efficacy of novel NHC precursor's derivatives (1, 2a–g)
on BChE/AChE activities was obtained conforming to the spectro-
photometric procedure of Ellman et al.[77] Butyrylthiocholine iodide
(BChI) and also acetylthiocholine iodide (AChI) compounds were used
as substrates of the both reactions.[78,79] In this part, 5,5′-dithio-bis(2-
nitro-benzoic)acid (DTNB) was used for the estimation of the BChE/
AChE activities. Briefly, 100 μL of buffer solution (pH 8.0, Tris/HCl,
1.0 M) and diverse concentration of sample solutions (50–200 μL)
dissolved in deionized water were added to 50 μL of BChE/AChE
solutions (5.32 × 10−3 EU).[80–82] Then the mixture was incubated for
10 min at 20°C. Finally, 50 μL of DTNB (0.5 mM and 25 mL) of BChI/
AChI were added to incubated mixture. Also, the reaction was initiated
by the addition of 50 μL of BChI/AChI. Activities of these enzymes
1563 cm−1
;
benzonitrile): 2228 cm−1

ν(C N . Anal. calcd. for
C
26H26BrN3: C: 67.83, H: 5.69, N: 9.13. Found: C: 67.78, H: 5.66, N:
9.15. 1H NMR (400 MHz, DMSO-d6), δ; 2.21 and 2.28 (s, 12H,
─CH2(C6H)(CH3)4); 5.77 (s, 2H, ─CH2(C6H4)CN); 5.82 (s, 2H,
─CH2(C6H)(CH3)4); 7.18 (s, 1H, ─CH2(C6H)(CH3)4); 7.63–8.25 (m,
8H, Ar-H); 9.42 (s, 1H, 2-CH). 13C NMR (100 MHz, DMSO-d6), δ; 15.9
and 20.7 (─CH2(C6H)(CH3)4); 46.5 (─CH2(C6H4)CN); 49.5 (─CH2(C6H)
(CH3)4); 111.2, 114.4, 114.6, 118.9, 130.6, 132.0, 132.3, 132.8, 133.3,
133.4, 134.7, 135.0, and 136.4. (Ar-C); 142.2 (2-CH).
|
4.1.9 Synthesis of 1-(3-cyanobenzyl)-3-(2,3,4,5,6-
pentamethyl-benzyl)-3H-benzoimidazol-1-ium
were evaluated spectrophotometrically at
412 nm.[83,84]
a
wavelength of
bromide 2g
The compound 2g was synthesized in the same method as that
described for 2a, but 1-(2,3,4,5,6-pentamethyl-benzyl)-1H-benzoimi-
dazole (1.95 g, 7 mmol) was used instead of 1-benzyl-1H-benzoimi-
|
4.2.3 Measurement of AG inhibitory activity

dazole. Yield: 2.78 g (84%); m.p.: 228–229°C; ν(C N benzimidazole):
AG inhibitory efficacy was performed using p-nitrophenyl-D-glyco-
pyranoside (p-NPG) as the substrate, according to the procedure of
Tao et al.[85] Samples were prepared by dissolving 10 mg in 10 mL
(EtOH/H2O). First, 100 μL of phosphate buffer was mixed with 20 μL
of the enzyme solution in phosphate buffer (0.15 U/mL, pH 7.4) and
10–100 μL of the sample. Multiple solutions in phosphate buffer were
prepared in case of getting full enzyme inhibition. Then it was pre-
incubated at 35°C for 12 min previous by adding the p-NPG to the
initiation of the reaction.[86] Also, 50 μL of p-NPG in phosphate buffer
(5 mM, pH 7.4) after preincubation was added and again incubated at
37°C. The absorbances were spectrophotometrically measured at
405 nm.[87] The IC50 amount was calculated from activity (%) versus
plant concentration plots. Lineweaver–Burk[88] graphs were used to
determine Vmax and other inhibition parameters. The Ki was calculated
from these graphs.
1560 cm−1
;
benzonitrile): 2229 cm−1

ν(C N . Anal. calcd. for
C
27H8BrN3: C: 68.35, H: 5.95, N: 8.86. Found: C: 68.37, H: 5.98, N:
8.84. 1H NMR (400 MHz, DMSO-d6), δ; 2.23 (d, 12H, J = 4 Hz
─CH2(C6)(CH3)5); 2.28 (s, 3H, ─CH2(C6)(CH3)5); 5.75 (s, 2H,
─CH2(C6H4)CN); 5.78 (s, 2H, ─CH2(C6)(CH3)5); 7.62–8.26 (m, 8H,
Ar-H); 9.34 (s, 1H, 2-CH). 13C NMR (400 MHz, DMSO-d6), δ; 16.9–17.2
and 17.5 (─CH2(C6)(CH3)5); 47.0 (─CH2(C6H4)CN); 49.4 (─CH2(C6)
(CH3)5); 112.2, 112.4, 114.3, 114.6, 118.9, 127.3, 130.6, 131.6, 132.0,
132.8, 133.2, 133.5, 134.4, 136.4, and 136.4. (Ar-C); 142.1 (2-CH).
|
4.2 Biochemical studies
|
4.2.1 hCA isoenzymes purification and inhibition
studies
In this work, both CA isoenzymes were separated and purified by
Sepharose-4B-L-tyrosine sulfanilamide affinity chromatography in a
single stage.[66–68] The column chemical material of affinity chroma-
tography containing Sepharose-4B-L-tyrosine-sulfanilamide was cre-
ated conforming to a former procedure.[69,70] The protein molecules
flow in the column eluates was spectrophotometrically obtained at
280 nm as explained formerly.[71] CA isoenzymes’ activity investiga-
tion was obtained using the spectrophotometric style of Verpoorte
et al.[72] as described formerly. In this work, changes in absorbance
|
4.3 X-ray crystallography studies
Single crystal X-ray diffraction data were collected at room tempera-
ture for 2g and 2f on a Rigaku Oxford Xcalibur diffractometer with an
Eos-CCD detector using graphite-monochromated Mo-Kα radiation
(λ = 0.71073 Å) with CrysAlisPro software.[89] Data reduction and
analytical absorption corrections were performed by CrysAlisPro
program.[90] Utilizing OLEX2,[91] structures were solved by Intrinsic
Phasing method with SHELXT[92] and refined by full-matrix least

10 of 11
TÜRKER ET AL.
|
squares on F2 in SHELXL.[93] The poor quality of the crystal due to the
high mosaicity causes the high R-value of 2g. Anisotropic thermal
parameters were applied to all non-hydrogen atoms. All hydrogen
atoms were positioned geometrically and refined riding on their
respecting carbon atom for both compounds. Bond lengths were fixed
at 0.93 Å (aromatic and imidazole carbon H), 0.96 Å (methyl H), and
0.97 Å (methylene H).
[18] A. Akıncıoğlu, H. Akıncıoğlu, I. Gülçin, S. Durdağı, C. T. Supuran, S.
Göksu, Bioorg. Med. Chem. 2015, 23, 3592.
[19] B. Arabaci, İ. Gülçin, S. Alwasel, Molecules 2014, 19, 10103.
[20] Ş. ArasHisar, O. Hisar, Ş. Beydemir, İ. Gülçin, T. Yanık, Acta Vet. Hung.
2004, 52, 413.
[21] A. Bertucci, A. Moya, S. Tambutté, D. Allemand, C. T. Supuran, D.
Zoccola, Bioorg. Med. Chem. 2013, 21, 1437.
[22] Ş. Beydemir, İ. Gülçin, J. Enzyme Inhib. Med. Chem. 2004, 19, 193.
[23] T. A. Çoban, Ş. Beydemir, İ. Gülçin, D. Ekinci, Biol. Pharm. Bull. 2007,
30, 2257.
[24] H. Gocer, F. Topal, M. Topal, M. Küçük, D. Teke, İ. Gülçin, S. H.
Alwasel, C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 441.
[25] U. M. Kocyigit, Y. Budak, M. B. Gürdere, F. Ertürk, B. Yencilek, P.
ACKNOWLEDGMENT
The authors acknowledge Dokuz Eylul University for the use of the
Oxford Rigaku Xcalibur Eos diffractometer (purchased under Univer-
sity Research Grant No: 2010.KB.FEN.13).
Taslimi, İ. Gulc
[26] U. M. Koçyiğit, P. Taslimi, H. Gezegen, İ. Gulc
Mol. Toxicol. 2017, 31(9), e21938.
̧
in, M. Ceylan, Arch. Physiol. Biochem. 2018, 124(1), 61.
̧
in, M. Ceylan, J. Biochem.
[27] H. I. Gul, K. Kucukoglu, C. Yamali, S. Bilginer, H. Yuca, İ. Ozturk, P.
Taslimi, İ. Gülçin, C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31,
568.
CONFLICT OF INTEREST
[28] H. I. Gul, E. Mete, P. Taslimi, I. Gulcin, C. T. Supuran, J. Enzyme Inhib.
Med. Chem. 2017, 32, 189.
The authors have declared no conflict of interest.
[29] İ. Gülçin, Ş. Beydemir, M. E. Büyükokuroğlu, Biol. Pharm. Bull. 2004,
27, 613.
ORCID
[30] A. Scozzafava, P. Kalın, C. T. Supuran, İ. Gülçin, S. Alwasel, J. Enzyme
Inhib. Med. Chem. 2015, 30, 941.
Aydın Aktaş
http://orcid.org/0000-0001-8496-6782
http://orcid.org/0000-0002-3171-0633
[31] P. Taslimi, I. Gulcin, B. Ozgeris, S. Goksu, F. Tumer, S. H. Alwasel, C. T.
Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 152.
[32] Ç. Bayrak, P. Taslimi, İ. Gülçin, A. Menzek, Bioorg. Chem. 2017, 72,
359.
Parham Taslimi
[33] İ. Gulçin, M. Abbasova, P. Taslimi, Z. Huyut, L. Safarova, A. Sujayev, V.
Farzaliyev, S. Beydemir, S. H. Alwasel, C. T. Supuran, J. Enzyme Inhib.
Med. Chem. 2017, 32, 1174.
REFERENCES
[1] S. Diez-Gonzalez, N. Marion, S. P. Nolan, Chem. Rev. 2009, 109,
3612.
[34] U. M. Koçyiğit, A. Taşkıran, P. Taslimi, A. Yokuş, Y. Temel, İ. Gulc
Biochem. Mol. Toxicol. 2017, 31(11), e21972.
[35] U. M. Kocyigit, Y. Budak, M. B. Gürdere, F. Ertürk, B. Yencilek, P.
Taslimi, İ. Gulcin, M. Ceylan, Synth Commun. 2017, 47(24), 2313.
[36] T. Dastan, U. M. Kocyigit, S. D. Dastan, C. Kiliçkaya, P. Taslimi, Ç.
Özge, M. Koparir, A. Çetin, C. Orek, İ. Gulcin, J. Biochem. Mol. Toxicol.
2017, 31(11), e21971.
̧in, J.
[2] Y. Sarı, A. Aktaş, D. B. Celepci, Y. Gök, M. Aygün, Catal. Lett. 2017,
147, 2340.
̧
[3] A. Aktaş, Y. Gök, Catal. Lett. 2015, 145, 631.
[4] A. Aktaş, Y. Gök, Transition Met. Chem. 2014, 39, 925.
[5] I. Yıldırım, A. Aktaş, D. B. Celepci, D. E. Hibbs, Y. Gök, P. A. Williams, B.
Hawkins, F. Lai, Res. Chem. Intermed. 2017, 43, 6379.
[6] S. Akkoç, V. Kayser, I. Ö. İlhan, D. E. Hibbs, Y. Gök, P. A. Williams, B.
Hawkins, F. Lai, J. Organomet. Chem. 2017, 839, 98.
[7] Y. Gök, S. Akkoç, H. Erdoğan, S. Albayrak, J. Enzyme Inhib. Med. Chem.
2016, 31, 1322.
̧
[37] P. Taslimi, S. Osmanova, İ. Gulçin, S. Sardarova, V. Farzaliyev, A.
Sujayev, R. Kaya, F. Koc, S. Beydemir, S. H. Alwasel, O. I. Kufrevioglu,
J. Biochem. Mol. Toxicol. 2017, 31(9), e21931.
[38] N. Bulut, U. M. Koçyiğit, I. H. Gecibesler, T. Dastan, H. Karci, P. Taslimi,
S. Durna Dastan, İ. Gulçin, A. Cetin, J. Biochem. Mol. Toxicol 2018,
[8] S. Akkoç, I. Ö. İlhan, Y. Gök, P. J. Upadhyay, V. Kayser, Inorg. Chim.
Acta 2016, 449, 75.
32(1), e22006.
[39] N. Öztaskın, T. Taslimi, A. Maras, S. Göksu, İ. Gülçin, Bioorg. Chem.
2017, 74, 104.
[9] S. Budagumpi, S. Endud, Organometallics 2013, 32(6), 1537.
[10] Y. Sarı, A. Aktaş, P. Taslimi, Y. Gök, İ. Gülçin, J. Biochem. Mol. Toxicol.
2018, 32(1), e22009.
[40] H. O. Tayeb, H. D. Yang, B. H. Price, F. I. Tarazi, Pharmacol. Ther. 2012,
134, 8.
[11] A. H. Rosenani, S. Y. Choo, S. Budagumpi, A. A. Abdullah, M. B. K.
Ahamed, A. M. S. Abdul Majid, Inorg. Chim. Acta 2015, 433, 35.
[12] A. Aktaş, Ü. Keleştemur, Y. Gök, S. Balcıoğlu, B. Ateş, M. Aygün, J. Iran
Chem. Soc. 2018, 15, 131.
[41] L. Zhang, S. Hogan, J. R. Li, S. Sun, C. Canning, S. J. Zheng, K. Zhou,
Food Chem. 2011, 126, 466.
[42] F. Hiroyuki, Y. Tomohide, O. Kazunori, J. Nutr. Biochem. 2001, 12, 351.
[43] T. Fujisawa, H. Ikegami, K. Inoue, Y. Kawabata, T. Ogihara, Metabolism
2005, 54, 387.
[13] A. Aktaş, P. Taslimi, İ. Gülçin, Y. Gök, Arch. Pharm. 2017, 350(6),
e1700045.
[44] S. Shobana, Y. N. Sreerama, N. G. Malleshi, Food Chem. 2009, 115,
1268.
[14] M. O. Karataş, H. Uslu, S. Sarı, M. A. Alagöz, A. Karakurt, B. Alıcı, C.
Bilen, E. Yavuz, N. Gencer, O. Arslan, J. Enzyme Inhib. Med. Chem.
2016, 31, 760.
[45] H. Wang, Y. J. Du, H. C. Song, Food Chem. 2010, 123, 6.
[46] A. Scozzafava, A. Mastrolorenzo, C. T. Supuran, Expert Opin. Ther. Pat.
2006, 16, 1627.
[15] P. Taslimi, E. Sujayev, F. Turkan, E. Garibov, Z. Huyut, V. Farzaliyev, S.
Mamedova, İ. Gulçin, J. Biochem. Mol. Toxicol. 2018, 32(2), e22019.
[16] N. Bulut, U. M. Koçyiğit, I. H. Gecibesler, T. Dastan, H. Karci, P. Taslimi,
[47] C. T. Supuran, A. Scozzafava, A. Casini, Med. Res. Rev. 2003, 23, 146.
[48] C. T. Supuran, A. Casini, A. Mastrolorenzo, A. Scozzafava, Mini Rev.
Med. Chem. 2004, 4, 625.
S. Durna Dastan, İ. Gulçin, A. Cetin, J. Biochem. Mol. Toxicol. 2018,
32(1), e22006.
[49] T. M. C. Adachi, K. Sakurai, N. Shihara, N. Shihara, K. Tsuda, K. Yasuda,
J. Endocrinol. 2003, 50, 271.
[17] Y. Akbaba, E. Bastem, F. Topal, İ. Gülçin, A. Maraş, S. Göksu, Arch.
Pharm. 2014, 347, 950.
[50] H. Laube, Clin. Drug Investig. 2002, 22, 141.

TÜRKER ET AL.
11 of 11
|
[51] X. Chen, Y. Zheng, Y. Shen, Curr. Med. Chem. 2006, 13, 109.
[52] M. Toeller, Eur. J. Clin. Invest. 1994, 24, 31.
[81] P. Taslimi, A. Sujayev, E. Garibov, N. Nazarov, Z. Huyut, S. H. Alwasel,
İ. Gülçin, J. Biochem. Mol. Toxicol. 2017, 31(7), e21897.
[82] H. I. Gul, A. Demirtas, G. Ucar, P. Taslimi, İ. Gülçin, Lett. Drug Des.
Discov. 2017, 14, 573.
[53] G. Slama, F. Elgrably, A. Sola, J. Mbemba, E. Larger, Diabetes Metab.
2006, 32, 187.
[54] E. Garibov, P. Taslimi, A. Sujayev, Z. Bingöl, S. Çetinkaya, İ. Gulcin, S.
Beydemir, V. Farzaliyev, S. H. Alwasel, C. T. Supuran, J. Enzyme Inhib.
Med. Chem. 2016, 31, 1.
[83] P. Taslimi, A. Sujayev, S. Mamedova, P. Kalın, İ. Gulcin, N. Sadeghian,
S. Beydemir, Ö. İ. Küfrevioglu, S. H. Alwasel, V. Farzaliyev, S.
Mamedov, J. Enzyme Inhib. Med. Chem. 2017, 32, 137.
[84] B. Turan, K. Sendil, E. Sengul, M. S. Gultekin, P. Taslimi, İ. Gulcin, C. T.
Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 79.
[85] Y. Tao, Y. Zhang, Y. Cheng, Y. Wang, Chromatography 2013, 27, 148.
[86] P. Taslimi, C. Caglayan, İ. Gulçin, J. Biochem. Mol. Toxicol. 2017, 31(12),
e21995.
[55] F. Ozbey, P. Taslimi, I. Gulcin, A. Maraş, S. Goksu, C. T. Supuran, J.
Enzyme Inhib. Med. Chem. 2016, 31, 79.
[56] A. Sujayev, E. Garibov, P. Taslimi, İ. Gülçin, S. Gojayeva, V. Farzaliyev,
S. H. Alwasel, C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31,
1531.
[57] C. Caglayan, I. Gulcin, J. Biochem. Mol. Toxicol 2018, 32(1), e22010.
[58] H. İ. Gül, M. Tuğrak, H. Sakagami, P. Taslimi, İ. Gülçin, C. T. Supuran, J.
Enzyme Inhib. Med. Chem. 2016, 31, 1619.
[87] P. Taslimi, H. Akıncıoğlu, İ. Gulçin, J. Biochem. Mol. Toxicol. 2017,
31(11), e21973.
[88] H. Lineweaver, D. Burk, J. Am. Chem. Soc. 1934, 56, 658.
[89] CrysAlisPro Software System, Version 1.171.38.43 (Rigaku Corpora-
tion, Oxford, UK, 2015).
[59] A. Innocenti, S. B. Ozturk Sarıkaya, I. Gulcin, C. T. Supuran, Bioorg.
Med. Chem. 2010, 18, 2159.
[60] S. Göksu, A. Naderi, Y. Akbaba, P. Kalın, A. Akıncıoğlu, İ. Gulcin, S.
Durdaği, R. E. Salmas, Bioorg. Chem. 2014, 56, 75.
[61] Y. Sarı, A. Aktaş, P. Taslimi, Y. Gök, İ. Gulçin, J. Biochem. Mol. Toxicol.
2018, 32(1), e22009.
[90] R. C. Clark, J. S. Reid, Acta Cryst. 1995, 51, 887.
[91] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard, H.
Puschmann, J. Appl. Cryst. 2009, 42, 339.
[92] G. M. Sheldrick, Acta Crystallogr. 2015, 71, 3.
[93] S. Parsons, H. D. Flack, T. Wagner, Acta Cryst. 2013, 69, 249.
[94] M. Torres-Naranjo, A. Suarez, G. Gilardoni, L. Cartuche, P. Flores, V.
Morocho, Molcules 2016, 21, 1461.
[62] S. Patil, A. Deally, B. Gleeson, H. Müller-Bunz, F. Paradisi, M. Tacke,
Metallomics 2011, 3, 74.
[63] A. Rosenani, S. Y. Choo, S. Budagumpi, B. Srinivasa, A. Amirul Al-
Ashraf, B. Mohamed, A. Khadeer, M. Amin, M. Abdul, Inorg. Chim.
2015, 433, 35.
[95] H. Teng, L. Chen, T. Fang, B. Yuan, Q. Lin, J. Funct. Foods 2017, 28,
306.
[64] B. Christer, E. Aakeröy, J. Desper, J. F. Urbina, Cryst. Growth Des.
2005, 5, 1283.
[65] A. Rosenani, S. Y. Choo, S. Budagumpi, A. A. Abdullah, M. B. K. Ahmed,
A. M. S. A. Majid, Inorg. Chim. Acta 2015, 433, 35.
[66] Ü. M. Koçyiğit, S. D. Daştan, P. Taslimi, T. Dastan, İ. Gülçin, J. Biochem.
Mol. Toxicol. 2018, 32(1), e22000.
SUPPORTING INFORMATION
Additional supporting information may be found online in the
Supporting Information section at the end of the article.
[67] M. Nar, Y. Çetinkaya, İ. Gülçin, A. Menzek, J. Enzyme Inhib. Med. Chem.
2013, 28, 402.
[68] L. Polat Kose, İ. Gülçin, H. Özdemir, A. Atasever, S. H. Alwasel, C. T.
Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 773.
[69] A. Yıldırım, U. Atmaca, A. Keskin, M. Topal, M. Çelik, İ. Gülçin, C. T.
Supuran, Bioorg. Med. Chem. 2015, 23, 2598.
Crystallographic data as .cif files for the structures reported in this
paper have been deposited at the Cambridge Crystallographic Data
Center with CCDC 1584233 for compound 2f and 1584223 for 2g.
Copies of the data can be obtained free of charge at http://www.ccdc.
cam.ac.uk/conts/retrieving.html or from the Cambridge Crystallo-
graphic Data Center, 12, Union Road, Cambridge CB2 1EZ, UK. Fax:
(+44) 1223-336-033, Email: deposit@ccdc.cam.ac.uk.
[70] M. Topal, I. Gulcin, Turk. J. Chem. 2014, 38, 894.
[71] C. Yamali, H. İ. Gul, A. Ece, P. Taslimi, İ. Gülçin, Chem. Biol. Drug Des.
2018, 91(4), 854.
[72] J. A. Verpoorte, S. Mehta, J. T. Edsall, J. Biol. Chem. 1967, 242, 4221.
[73] U. M. Kocyigit, Y. Budak, F. Eligüzel, P. Taslimi, D. Kılıç, İ. Gulc
̧
in, M.
Ceylan, Arch. Pharm. 2017, 350, e1700198.
[74] C. T. Supuran, Nat. Rev. Drug Discov. 2008, 7, 168.
[75] M. M. Bradford, Anal. Biochem. 1976, 72, 248.
[76] P. Taslimi, I. Gulcin, N. Oztaskın, Y. C
̧
etinkaya, S. Go
̈
ksu, S. H. Alwasel,
How to cite this article: Türker F, Barut Celepci D, Aktaş A,
et al. meta-Cyanobenzyl substituted benzimidazolium salts:
Synthesis, characterization, crystal structure and carbonic
anhydrase, α-glycosidase, butyrylcholinesterase, and
acetylcholinesterase inhibitory properties. Arch Pharm Chem
Life Sci. 2018;1–11.
C. T. Supuran, J. Enzyme Inhib. Med. Chem. 2016, 31, 603.
[77] G. L. Ellman, K. D. Courtney, V. Andres, R. M. Featherston, Biochem.
Pharmacol. 1961, 7, 88.
[78] M. B. Colovic, D. Z. Krstic, T. D. Lazarevic-Pasti, A. M. Bondžić, V. M.
Vasić, Curr. Neuropharmacol. 2013, 11, 315.
[79] N. Oztaskin, Y. Cetinkaya, P. Taslimi, S. Göksu, İ. Gülçin, Bioorg. Chem.
2015, 60, 49.
https://doi.org/10.1002/ardp.201800029
[80] K. Aksu, B. Özgeris, P. Taslimi, A. Naderi, İ. Gülçin, S. Göksu, Arch.
Pharm. 2016, 349, 944.