Fe3O4@SiO2@Im-bisethylFc [HC2O4] as a novel recyclable heterogeneous nanocatalyst for synthesis of bis-coumarin derivatives

Article abstract of DOI:10.1002/aoc.4773

Nanomagnetic bisethylferrocene-containing ionic liquid supported on silica-coated iron oxide (Fe₃O₄@SiO₂@Im-bisethylFc [HC₂O₄]) as a novel catalyst was designed and synthesized. The described catalyst

Full text of DOI:10.1002/aoc.4773

Received: 11 September 2018
DOI: 10.1002/aoc.4773
Revised: 5 November 2018
Accepted: 26 November 2018
F U L L P A P E R
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] as a novel recyclable
heterogeneous nanocatalyst for synthesis of bis‐coumarin
derivatives
Reza Teimuri‐Mofrad
| Shabnam Tahmasebi | Elmira Payami
Department of Organic and Biochemistry,
Faculty of Chemistry, University of
Tabriz, Tabriz, Iran
Nanomagnetic bisethylferrocene‐containing ionic liquid supported on silica‐
coated iron oxide (Fe3O4@SiO2@Im‐bisethylFc [HC2O4]) as a novel catalyst
was designed and synthesized. The described catalyst was recycled and used
without change in the time and efficiency of the condensation reaction. The
Fourier transform‐infrared spectroscopy (FT‐IR), scanning electron microscopy
images, X‐ray diffraction patterns, energy‐dispersive X‐ray spectroscopy, trans-
mission electron microscope and vibrating‐sample magnetometer results con-
firmed the formation of Fe3O4@SiO2@Im‐bisethylFc [HC2O4] magnetic
Correspondence
Reza Teimuri‐Mofrad, Department of
Organic and Biochemistry, Faculty of
Chemistry, University of Tabriz, Tabriz,
Iran.
Email: teymouri@tabrizu.ac.ir
1
nanoparticle. The novel bis‐coumarin derivatives were identified by H‐NMR,
13C‐NMR, FT‐IR and CHNS analysis.
KEYWORDS
4‐hydroxycoumarin, bis‐coumarin, ferrocene, ionic liquids, magnetic nanocatalyst
1 | INTRODUCTION
due to the reversibility, regeneration at low potential,
and generation of stable redox states.[9] In addition, they
In recent years, heterogeneous catalysts based on ionic
liquids (ILs) have become very important because
magnetic nanoparticles (MNPs)‐supported catalysts are
a bridge between homogeneous and heterogeneous
catalysts,[1,2] and those MNPs are suitable supports for
ILs.[3] ILs also have received a great deal of attention as
a catalyst in green organic synthesis because of their spe-
cial characteristics, for example, high ionic conductivity,
excellent chemical stability, no flammability, thermal
and chemical stability, very low vapor pressure, selective
solubility of water and organic solvents, recyclability
and negligible volatility.[4–7] During the past few decades,
ferrocene‐based ligands have been widely studied due
to their electron‐rich aromatic structural motifs.[8]
Ferrocene (Fc) and its derivatives are excellent and are
often used in electrochemical systems as a protein bio-
marker or redox active species for detecting biomolecules,
are relatively low cost, thermal stability, high tolerance
to moisture and oxygen, and have very unique chemical
properties that make these materials attractive.[8] MNPs
have attracted considerable interest due to magnetic and
electrical properties, their extremely catalytic activity
and the high surface to volume ratio, the wide range
of applications in drug delivery systems, targeted gene
therapy, ion exchange separation, magnetic resonance
imaging, biosensors, magnetic data storage, and environ-
mental remediation and catalysis.[10] The combination
of the magnetic properties of Fe3O4 and SiO2 shell and
modification of this with ferrocene, give a stable, well‐
defined electrochemical signal, simplified procedure
and accelerate the determination of pathogens in
biological objects.[11]
4‐Hydroxycoumarin has become very popular due to
its special properties, as well as its many biological
Appl Organometal Chem. 2019;e4773.
wileyonlinelibrary.com/journal/aoc
© 2019 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.4773

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TEIMURI‐MOFRAD ET AL.
uses, and this has led to the synthesis and identification
of various derivatives of bis‐coumarin. These derivatives
have been found useful in an extensive range of biological
and pharmaceutical actions, including enzyme inhibi-
tors,[12,13] anticoagulants,[14,15] antioxidants,[16,17] antitu-
2 | RESULTS AND DISCUSSION
2.1 | Preparation and characterization of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
magnetic nanocatalyst
[19]
mor drugs,[18] anti‐diabetic (α‐glucosidase inhibitors)
urease inhibitors,[20,21] anticancers,[22] antibacterials,[23]
inhibit c‐Met phosphorylation in BaF3/TPR‐Met and
EBC‐1 NSCLC cell lines,[24] antimicrobial,[25] antiviral,[26]
proliferation inhibition of K‐562[27] and inhibit HIV‐1.[28]
Recently, several methods have been reported for the syn-
thesis of bis‐coumarin by the reaction of 4‐
hydroxycoumarin and various aldehydes in the presence
of various homogeneous and heterogeneous catalysts
and under various reaction conditions, such as
tetrabutylammonium bromide (TBAB),[29] molecular
iodine,[30] [bmin] BF4,[31] SO3H‐functionalized IL,[32]
The synthesis process of magnetic nanocatalyst
(Fe3O4@SiO2@Im‐bisethylFc [HC2O4]) is shown in
Scheme 2. In the first step, Fe3O4 nanoparticles were pre-
pared by
a
chemical co‐precipitating method.
Then, Fe3O4 nanoparticles with an outer layer of silica,
which not only prevents aggregation of the nano‐sized
particles but also provides numerous surfaces for Si‐OH
groups for further modifications, were synthesized. The
silica‐coated MNPs were subsequently reacted with
(3‐chloropropyl)triethoxysilane.[45–47] Then, chlorine
was replaced by imidazole on the modified
nanoparticle surface.
sodium
dodecyl
sulfate,[33]
piperidine,[34]
n‐
dodecylbenzene sulfonic acid (DBSA),[35] [pyridin‐SO3H]
Cl,[36] TrBr and [Fe3O4@SiO2@(CH2)3‐Im‐SO3H]Cl,[37]
MNPs‐PSA[38] and Fe3O4@SiO2@(CH2)3semicarbazide‐
SO3H/HCl.[39] Although all the procedures for the syn-
thesis of corresponding bis‐coumarin have their merits,
the main disadvantages of these methods are often
tedious work‐up procedures, low yields, harsh reaction
conditions, and the use of toxic, corrosive and expensive
catalysts, and the recovery of these catalysts are
often difficult.
Herein, in continuation of previous research on the
synthesis of ferrocene‐IL‐based MNPs for catalysis
of multi component reactions,[40–44] in this work we
report the synthesis and structural characterization
of Fe3O4@SiO2@Im‐bisethylFc [HC2O4] as a novel recy-
clable heterogeneous nanocatalyst and also, using this
new synthesized nanocatalyst, we were able to provide a
simple and effective way of synthesizing bis‐coumarin
derivatives under reflux conditions in ethanol (Scheme 1).
In the second step, ethylferrocene was reacted with 5‐
chloropentan‐2‐one in the presence of sulfuric acid and
methanol mixture, and 5‐chloro‐2,2‐bis (ethylferrocenyl)
pentane was obtained. Finally, bisethylferrocene‐
containing IL supported on MNPs was synthesized via
the reaction of imidazolepropyl modified silica‐coated
MNPs with 5‐chloro‐2,2‐bis (ethylferrocenyl) pentane to
afford Fe3O4@SiO2@Im‐bisethylFc [Cl], afterwards the
reaction between Fe3O4@SiO2@Im‐bisethylFc [Cl] and
oxalic acid mono sodium salt resulted in the synthesis
of the final magnetic nanocatalyst (Scheme 2).
The
structure
of
Fe3O4@SiO2@Im‐bisethylFc
[HC2O4] catalyst was studied and completely character-
ized using Fourier transform‐infrared spectroscopy (FT‐
IR), field‐emission‐scanning electron microscopy (FE‐
SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐
ray diffraction (XRD), transmission electron microscopy
(TEM) and vibrating‐sample magnetometer (VSM)
analysis.
SCHEME 1 The synthesis of bis‐coumarin derivatives using Fe3O4@SiO2@Im‐bisethylFc [HC2O4] as an efficient catalyst

TEIMURI‐MOFRAD ET AL.
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SCHEME 2 Synthesis of Fe3O4@SiO2@Im‐bisethylFc [HC2O4] magnetic nanocatalyst
The corresponding FT‐IR spectra of the MNPs:
(a) Fe3O4, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2‐(CH2)3Cl,
(d) Fe3O4@SiO2@Im, (e) Fe3O4@SiO2@Im‐bisethylFc
[Cl] and (f) Fe3O4@SiO2@Im‐bisethylFc [HC2O4] are
shown in Figure 1. In the FT‐IR spectrum of the Fe3O4
(Figure 1a), the presence of two absorption peaks
at about 584 cm−1 and 3434 cm−1 related to Fe‐O bonds
and hydroxyl groups present at the nanoparticle
surface, respectively. The two absorption peaks observed
at 802 cm−1 and 1088 cm−1 in the FT‐IR spectrum of
Fe3O4@SiO2 MNPs (Figure 1b) are related to the Si‐O‐Si
bond symmetric and asymmetric tensile vibrations,
respectively. Also, the observed peak at about 465 cm−1
was assigned to the bending vibration of Si‐O‐Si bond.
The observed absorption peak at 3445 cm−1 is also related
to hydroxyl groups. The FT‐IR spectrum of Fe3O4@SiO2‐
(CH2)3Cl (Figure 1c), in addition to having similar peaks
in the two interpreted spectra above, has two peaks at
2849 cm−1 and 2918 cm−1, which relate to the symmetric
and asymmetric tensile vibrations in the carbon chain,
respectively. In the FT‐IR spectrum of Fe3O4@SiO2@Im
(Figure 1d), the appearance of new peaks at 1485 cm−1
and 1515 cm−1 relates to the tensile vibrations of C=C
and C=N in the imidazole ring, respectively. Finally,
the FT‐IR spectra of Fe3O4@SiO2@Im‐bisethylFc
[HC2O4] MNPs (Figure 1f) show an absorption peak at
about 1682 cm−1, which was related to the vibration
of the carbonyl bond, and the peak that appeared at
1089 cm−1 referred to the tensile vibration of the C‐O
bond of the anion.
The surface morphology and particle size of: (a)
Fe3O4@SiO2, (b) Fe3O4@SiO2@Im‐bisethylFc [Cl] and
(c) Fe3O4@SiO2@Im‐bisethylFc [HC2O4] nanoparticles
were studied by FE‐SEM analysis, and the images are
shown in Figure 2. Spherical morphology with an average
FIGURE 1 The Fourier transform‐infrared (FT‐IR) spectra of (a)
Fe3O4, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@(CH2)3Cl, (d)
Fe3O4@SiO2@Im, (e) Fe3O4@SiO2@Im‐bisethylFc [Cl] and (f)
Fe3O4@SiO2@ Im‐bisethylFc [HC2O4]

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TEIMURI‐MOFRAD ET AL.
FIGURE 2 Field‐emission‐scanning electron microscopy (FE‐SEM) images of (a) Fe3O4@SiO2, (b) Fe3O4@SiO2@Im‐bisethylFc [Cl] and
(c) Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
diameter of about 20 nm for catalyst was observed. Also,
according to the particle size distribution diagram of
the final synthesized nanocatalyst Fe3O4@SiO2@Im‐
TABLE 1 EDX analysis data for Fe3O4@SiO2@Im‐bisethylFc
[HC2O4]
Element
C
N
O
Si
Fe
Total
Weight (%)
36.88
4.26
50.93
5.20
2.73
100.00
FIGURE
5
X‐ray diffraction (XRD) patterns of (a)
FIGURE
3
Particle
size
distribution
diagram
of
Fe3O4@SiO2@Im‐bisethylFc [Cl] and (b) Fe3O4@SiO2@Im‐
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
bisethylFc [HC2O4]
FIGURE 4 Energy‐dispersive X‐ray spectrometry (EDX) analysis of (a) Fe3O4@SiO2@Im‐bisethylFc [Cl] and (b) Fe3O4@SiO2@Im‐
bisethylFc [HC2O4]

TEIMURI‐MOFRAD ET AL.
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bisethylFc [HC2O4] as shown in Figure 3, the nanoparti-
cle size of the final nanocatalyst is about 20 nm.
The EDX spectra of the novel synthesized nanocatalyst
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] are shown in
Figure 4. Accordingly, the presence of the elements Fe,
Cl, Si, O, N and C in the synthesized nanocatalyst is cor-
roborated. The elements ratio of the Fe3O4@SiO2@Im‐
bisethylFc [HC2O4] nanocatalyst was measured by EDX
analysis, and data were collected in Table 1. It is notewor-
thy that there is no chlorine in the final nanocatalyst,
which indicates the successful replacement of chlorine
with oxalate in the final nanocatalyst.
The XRD patterns of the modified Fe3O4 nanoparti-
cles are depicted in Figure 5. As can be noted from
the spectra, the diffusion pattern of the modified Fe3O4
nanoparticles shows only the crystalline dispersions of
the Fe3O4 MNPs. The presence of similar peaks in the
spectra of Fe3O4@SiO2@Im‐bisethylFc [Cl] and
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] indicates that the
crystalline structure of the nanoparticles is the same,
and this proves that the crystalline structure of the
nanoparticles remains unchanged during the steps of
the surface modification.
FIGURE 6 Transmission electron microscopy (TEM) image of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Figure 6 shows the TEM image analysis. TEM images
were used to estimate the particle size of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4], which was deter-
mined from the histogram data to be smaller than 40
nm. Also, from the resulting TEM image, we find that
core‐shell nanoparticles are formed.
FIGURE 7 Vibrating‐sample magnetometer (VSM) curves of (a)
Fe3O4, (b) Fe3O4@SiO2, (c) Fe3O4@SiO2@(CH2)3Cl, (d)
Fe3O4@SiO2@Im, (e) Fe3O4@SiO2@Im‐bisethylFc [Cl] and (f)
Fe3O4@SiO2@ Im‐bisethylFc [HC2O4]
TABLE 2 Optimization of solvent, temperature, catalyst and amount of catalyst in the synthesis of bis‐coumarin derivative 3a
Entry Catalyst
Catalyst amount (mg) Solvent
Temperature (°C) Time (hr) Yield (%)
1
–
–
4
4
4
4
4
4
4
4
4
4
2
6
Free
80
7.3
5
9
32
23
39
48
71
96
56
88
91
85
90
91
2
Fe3O4
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
Free
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
80
3
Fe3O4@SiO2
5
4
Fe3O4@SiO2@(CH2)3Cl
5
5
Fe3O4@SiO2@Im
4
6
Fe3O4@SiO2@Im‐bisethylFc [Cl]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
3
7
1
8
3
9
EtOH:H2O (50:50) Reflux
2
10
11
12
13
MeOH
CH2Cl2
EtOH
Reflux
Reflux
Reflux
Reflux
2
3
2.3
2
EtOH

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TEIMURI‐MOFRAD ET AL.
TABLE 3 The synthesis of new bis‐coumarin derivatives in the presence of 4 mg Fe3O4@SiO2@Im‐bisethylFc [HC2O4] under reflux in
ethanol conditions
Entry
Aldehyde
Structure
Time (hr)
Yield (%)
Melting point (ºC)
1
4.30
88
185–188
2
3
5
84
160–162
188–190
4.30
87
84
4
5
6
5.15
150–152
273–275
125–127
4
90
89
4.15
(Continues)

TEIMURI‐MOFRAD ET AL.
7 of 16
TABLE 3 (Continued)
Entry
Aldehyde
Structure
Time (hr)
Yield (%)
Melting point (ºC)
7
4.45
85
206–208
8
3.30
91
308–310
9
4.45
85
222–224
10
4.45
86
170–172
11
3
93
267–269
The M‐H loop behavior of all intermediates towards
the desired catalyst is studied from VSM at room tem-
perature (RT), varying the applied magnetic field (H)
during the range of −10 000 to 10 000 Oe exhibit
(Figure 7). The saturation magnetizations (Ms) are
found to be 58.88, 43.70, 34.7, 28.38, 20.8 and 18.63
emu/g for Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@(CH2)3Cl,
Fe3O4@SiO2@Im, Fe3O4@SiO2@Im‐bisethylFc [Cl] and
Fe3O4@SiO2@ Im‐bisethylFc [HC2O4], respectively. The
synthesized nanoparticles exhibit superparamagnetic

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TEIMURI‐MOFRAD ET AL.
behavior. The value of saturation magnetization of all
intermediates towards the desired catalyst has decreased
compared with the pure Fe3O4. This difference suggests
that silica and ferrocene‐tagged IL is coated on the sur-
face of Fe3O4 MNPs. In addition, we proved the
magneticity of the synthesized nanocatalyst with an
external magnet.
2.2 | Application of Fe3O4@SiO2@Im‐
bisethylFc [HC2O4] as a catalyst in the
synthesis of bis‐coumarin derivatives
In order to optimize the reaction conditions, the reaction
of 4‐hydroxycoumarin and benzaldehyde was chosen as a
model reaction. Then we examined the reaction under
various conditions, including different solvents, catalyst
and temperatures, and also the use of different amounts
of the synthesized nanocatalysts. The results are reported
in Table 2, and the optimal conditions were obtained for
reaction under reflux in ethanol and 4 mg of nanocatalyst
for 1 mmol of benzaldehyde (Table 2, entry 7).
After improving the reaction conditions, we synthe-
sized the bis‐coumarin derivatives with different aro-
matic aldehydes under optimal conditions. According
to the results reported in Table 3, bis‐coumarin deriva-
tives with aromatic aldehydes that have electron‐
withdrawing groups are synthesized over a short period
of time and with high efficiency compared with
SCHEME 3 The synthesis of bis‐coumarin derivatives in the
presence of 4 mg Fe3O4@SiO2@Im‐bisFc [HC2O4] under reflux in
ethanol conditions
SCHEME 4 Synthesis of aromatic aldehyde derivatives (5a–5k)

TEIMURI‐MOFRAD ET AL.
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aromatic aldehydes that have electron‐donating groups
(Scheme 3).
We also synthesized a series of aromatic aldehydes
(Scheme 4),[38–43] and applied them to synthesize new
bis‐coumarin derivatives using condensation of these
aldehydes and 4‐hydroxycoumarin catalyzed by
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] nanocatalyst under
optimized conditions (Table 3).
After synthesis of some novel bis‐coumarin derivatives
(3d–3n), in order to investigate the homoselectivity[48–51]
of the synthesized nanocatalyst, we selected the reaction
of terephthaldehyde (5l) as a dialdehyde derivative with
4‐hydroxycoumarin in the presence of Im‐bisethylFc
[HC2O4] as a catalyst under optimized condition. Under
similar conditions for the synthesis of bis‐coumarin deriv-
atives, in the reaction between 4‐hydroxycoumarin (2
equiv.) and terephthaldehyde (1 equiv.), 3,3′‐[(4‐
formylphenyl)methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3o)[38] was obtained in 71% yield. By controlling the
molar ratio of 4‐hydroxycoumarin (4 equiv.) toward
terephthaldehyde (1 equiv.), in this condensation reac-
FIGURE 8 Various Bronsted and Lewis acid and base sites of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] nanocatalyst
first, 4‐hydroxycoumarin reacts with the carbonyl group
of the aldehyde, which is activated by Fe3O4@SiO2@Im‐
bisethylFc [HC2O4] to produce the intermediate
arylidenemalononitrile I. Then intermediate II was pre-
pared by dehydration reaction from I. In the next step,
the catalyst‐activated 4‐hydroxycoumarin undergoes a
Michael‐type addition reaction with II and, finally, the
bis‐coumarin derivative 3a was produced.
tion,
3,3′,3′′,3′′′‐[1,4‐phenylenebis
(methanetriyl)]
(3p)[36]
was
tetrakis(4‐hydroxy‐2H‐chromen‐2‐one)
gained in 82% yield (Scheme 5).
The
Fe3O4@SiO2@Im‐bisethylFc
[HC2O4]
Finally, we investigated the reusability of the catalyst
under reflux conditions in the presence of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] nanocatalyst. After
completion of the reaction, the catalyst was easily sepa-
rated from the reaction mixture using external magnets.
Subsequently, recycled magnetic nanocatalyst was
washed with ethanol and dried in a vacuum. The recov-
ered catalyst was reused for six runs (Figure 9).
nanocatalyst has several Bronsted and Lewis acid and
base sites, which can act as active sites of the nanocatalyst
to promote this reaction (Figure 8). The Fe in the
ferrocenyl unit of nanocatalyst can act as a Lewis acid.
The logical mechanism for the preparation of bis‐
coumarin derivatives by using Fe3O4@SiO2@Im‐
bisethylFc [HC2O4] as catalyst is shown in Scheme 6. At
SCHEME 5 Investigation of the
homoselectivity in the condensation
reaction of 4‐hydroxycoumarin with
terephthaldehyde

10 of 16
TEIMURI‐MOFRAD ET AL.
SCHEME 6 The logical mechanism for the synthesis of bis‐coumarin derivative 3a in the presence of Fe3O4@SiO2@Im‐bisethylFc
[HC2O4] MNPs catalyst
method offers a lot of advantages over most of
the reported methods, such as, clean, simple and straight-
forward work‐up, savings in energy consumption, a short
reaction time and high yields.
3 | CONCLUSIONS
In this article, novel bisferrocenyl‐based modified Fe3O4
MNPs were synthesized by using a facile co‐preparation
technique to investigate the catalytic application. The
morphology and structure of the synthesized nanoparti-
cles were characterized by a variety of methods, such as
FT‐IR spectroscopy, SEM and XRD techniques. Then
the catalytic activity of the synthesized MNPs was investi-
gated for the synthesis of some novel bis‐coumarin deriv-
atives. These MNPs exhibited good catalytic activity.
Noteworthy advantages of this study are the relative
simplicity of product isolation, cleaner reaction profiles,
high yields, recyclability and reusability of the
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] catalyst.
FIGURE 9 Reusability of Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
as a catalyst in the synthesis of bis‐coumarin derivatives
The efficiency of the present method compared with a
number of other reported works for the synthesis of bis‐
coumarin is summarized in Table 4. Although each of
these methods has their own advantages, they suffer from
some drawbacks, such as the use of long reaction times,
low yield and use of non‐recyclable catalyst. The present

TEIMURI‐MOFRAD ET AL.
11 of 16
TABLE 4 Comparison of results using Fe3O4@SiO2@Im‐bisethylFc [HC2O4] MNPs with results obtained by other works for the synthesis
of bis‐coumarin
Time
(min)
Yield
(%)
Entry
Catalyst
Conditions
Ref.
[36]
1
2
3
4
5
[Pyridin‐SO3H]Cl
15 mol %; solvent‐free/80°C
7 mg; solvent‐free/100°C
15 mol%; solvent‐free/100°C
4.5 mg; solvent‐free/RT
0.01 g; solvent‐free/80°C
14
12
20
6
88
93
92
94
95
[37]
[37]
[38]
[39]
[Fe3O4@SiO2@(CH2)3‐Im‐SO3H]Cl
TrBr
MNPs‐PSA
Fe3O4@SiO2@(CH2)3semicarbazide‐SO3H/
30
HCl
[52]
[31]
[33]
[32]
6
SiO2Cl
75 mg; CH2Cl2/40°C
400 mol%; 60–70°C
170
120
150
120
60
85
84
90
95
96
7
[bmim]BF4
8
Sodium dodecyl sulfate
IL [PSebim][OTf]
Fe3O4@SiO2@Im‐bisethylFc [HC2O4]
20 mol%; water/60°C
10 mol%; dried CH2Cl2/70°C
4 mg; EtOH/reflux
9
10
This work
RT, room temperature.
mmol) to 200 mL water under nitrogen. Then, under
rapid mechanical stirring, 2 M ammonia solution was
added, and the pH value was controlled in the range
9 ≤ pH ≤ 12. The mixture was stirred at 70°C for 15
min. The magnetite precipitate Fe3O4 was washed with
distilled water and ethanol, and was dried under vacuum.
Two grams of Fe3O4 nanoparticles was dispersed in a
mixture of 70 mL ethanol, 30 mL deionized water and
30 mL ammonia aqueous solution, followed by the addi-
tion of 4 mL tetraethyl orthosilicate (TEOS). The mixture
was stirred with a mechanical stirrer for 24 hr. The mod-
ified nanoparticles (Fe3O4@SiO2) were separated by a
magnet from the reaction medium and washed with eth-
anol. The desired product was dried under vacuum.
4 | EXPERIMENTAL
4.1 | General considerations
All chemicals were purchased from Merck or Aldrich
chemical companies, and were used without further puri-
fication. Melting points were determined with a MEL‐
TEMP model 1202D and are uncorrected. FT‐IR spectra
were recorded on a Bruker Tensor 27 spectrometer as
1
KBr disks. The H‐NMR spectra were recorded with a
Bruker Spectrospin Avance 400 MHz spectrometer with
CDCl3 or DMSO‐d6 as solvent, and TMS as internal stan-
dard. 13C‐NMR spectra were determined on the same
instrument at 100 MHz. All chemical shifts were reported
as δ (ppm) relative to solvent peaks as internal standards,
and coupling constants (J) are given in Hz. Elementary
analyses were performed on a Vario EL III analyzer.
XRD patterns of samples were taken on a Siemens D500
XRD diffractometer (CuK radiation, λ = 1.5406 A). EDX
and FE‐SEM images of the nanoparticles were visualized
by a TESCAN MIRA3 FE‐SEM. TEM images were
obtained with a Zeiss EM 10C electron microscope. Mag-
netization measurement was carried out with a model
155 alternative gradient force magnetometer at RT.
4.2.2 | Preparation of Fe3O4@SiO2‐
(CH2)3Cl magnetic nanoparticles
Two grams of Fe3O4‐silica‐coated nanoparticles was
added to 70 mL of dry toluene and placed in an ultrasonic
bath for 30 min, then 3.18 mL of (3‐chloropropyl)
trimethoxysilane was added dropwise to the mixture.
The mixture was stirred mechanically for 48 hr at 90°C.
Modified nanoparticles [Fe3O4@SiO2‐(CH2)3Cl] were sep-
arated by a magnet from the reaction medium, washed
with ethanol and dried under vacuum.
4.2 | Synthesis of Fe3O4@SiO2@Im‐
bisethylFc [HC2O4] nanocatalyst
4.2.1 | Preparation of silica‐coated Fe3O4
nanoparticles
4.2.3 | Preparation of Fe3O4@SiO2‐Imid
magnetic nanoparticles
Nanoparticles of Fe3O4 were produced by adding
FeCl3·6H2O (5.4 g, 20 mmol) and FeCl2·4H2O (1.9 g, 10
Two grams of Fe3O4@SiO2‐(CH2)3Cl nanoparticles was
added to 70 mL of dry toluene and placed in an ultrasonic

12 of 16
TEIMURI‐MOFRAD ET AL.
bath for 30 min, then 1 g of imidazole and 4 mL of Et3N
was added to the mixture. The mixture was stirred
mechanically for 24 hr at 95°C. Then, KI was added to
the mixture and stirred mechanically for 24 hr. Modified
nanoparticles (Fe3O4@SiO2‐Imid) were separated by a
magnet from the reaction medium, washed with ethanol
and dried under vacuum.
nanocatalyst was dried under vacuum. The modified
nanoparticle was identified using FT‐IR, FE‐SEM, EDX,
XRD, TEM and VSM analysis.
4.3 | General procedure for the synthesis
of aldehyde derivatives
4.3.1 | Alkoxybenzaldehyde derivatives
(5a–5d)
4.2.4 | Synthesis of 5‐chloro‐2,2‐bis
(ethylferrocenyl)pentane
A mixture of benzaldehyde derivatives (1 mmol), com-
pounds (3‐chloropropanol or 2‐chloroethanol; 1 mmol)
and potassium carbonate (3 mmol) in dimethylsulfoxide
was stirred for 8 hr. After completion of the reaction,
which was monitored by thin‐layer chromatography
(TLC), the reaction mixture was diluted with water and
extracted with dichloromethane. The solvent was
removed under reduced pressure and the residue was
purified through column chromatography.[53,54]
At first, a mixture of dry methanol (5 mL) and sulfuric
acid (50 mmol, 5.08 g) was mixed at RT under argon gas
for 1 day. Then, the ethylferrocene (26 mmol, 5.58 g)
was added to the mixture. After 20 min stirring, 5‐
chloro‐2‐pentanone (13 mmol, 1.5 mL) was added to the
mixture at 60°C. The mixture was stirred for 10 hr at this
temperature. Then the reaction mixture was cooled to RT
and, after neutralization with sodium carbonate, was
extracted with dichloromethane (3 × 25 mL). Then the
solvent was removed by rotary evaporator and at the
end the residue was purified by column chromatography.
5‐Chloro‐2,2‐bis (ethylferrocenyl) pentane was obtained
in 65% yield as orange oil with relatively high
viscosity.[40]
4.3.2 | Bromobenzaldehyde derivatives
(5e, 5f)
Benzaldehyde derivatives (1 mmol) were dissolved in ace-
tone (10 mL), then potassium carbonate (1 mmol) was
added and the mixture was stirred for 24 hr under reflux.
Then, 1,2‐dibromoethane (10 mmol) and potassium car-
bonate (1 mmol) were added. The mixture was stirred
for 72 hr under reflux and progress was controlled by
TLC. After cooling to RT, water (20 mL) was added and
the mixture was extracted with dichloromethane. The
combined organic layers were washed with brine, dried
over anhydrous sodium sulfate and the solvents were
removed under reduced pressure. The residue was puri-
fied through column chromatography.[55,56]
4.2.5 | Synthesis of Fe3O4@SiO2@Im‐
bisethylFc [cl]
Two grams of Fe3O4@SiO2‐Imid nanoparticles in 70 mL
toluene was placed in the ultrasonic bath for 30 min.
After fully dispersing of the nanoparticles, 1 g of 5‐
chloro‐2,2‐bis (ethylferrocenyl) pentane was added, and
the reaction mixture was stirred with a mechanical stirrer
at 90°C for 40 hr. Modified MNPs were separated from
the reaction medium via an external magnetic field and
washed with toluene. The desired product was dried
under vacuum.
4.3.3 | Aminobenzaldehyde derivatives
(5g–5l)
4.2.6 | Synthesis of Fe3O4@SiO2@Im‐
bisethylFc [HC2O4]
A mixture of benzaldehyde derivatives (1 mmol), com-
pounds (piperidine, 1‐methylpiperazine, benzimidazole,
morpholine and 1H‐imidazole; 1 mmol) and potassium
carbonate (1 mmol) in dimethylsulfoxide was refluxed
for 24 hr. After completion of the reaction, which was
monitored by TLC, the mixture was concentrated under
low pressure and left to cool. The mixture was then
poured into ice water and left overnight. The formed solid
was filtered, washed with water and crystallized with
methanol.[57,58]
At first, a mixture of oxalic acid dihydrate (2 mmol, 2.5 g)
and sodium hydroxide (1 mmol, 0.4 g) in 40 mL of etha-
nol:water (30:10) was stirred at RT for 30 min. Then,
0.5 g of Fe3O4@SiO2@Im‐bisethylFc [Cl] nanoparticles
was added and the mixture was put in the ultrasonic bath
for 30 min. The suspension was stirred at RT for 48 hr by
a mechanical stirrer. Modified nanoparticles were sepa-
rated from the reaction medium via an external magnet,
and washed with water and ethanol. The desired

TEIMURI‐MOFRAD ET AL.
13 of 16
32.20, 35.29, 57.31, 64.46, 104.47, 114.11, 116.08, 117.55,
123.87, 123.96, 127.82, 130.88, 132.12, 152.16, 156.90,
164.64, 164.87 ppm; anal. calcd for C28H22O8: C, 69.13%;
H, 4.56%; found: C, 68.93%; H, 4.61%.
4.4 | General procedure for the synthesis
of bis‐coumarin derivatives
A
mixture of aromatic aldehyde (1 mmol), 4‐
hydroxycoumarin (2 mmol) and 4 mg of
Fe3O4@SiO2@Im‐bisethylFc [HC2O4] nanocatalyst in 30
mL of ethanol was stirred under reflux conditions for an
appropriate time. After completion of the reaction follow
by TLC (n‐hexane:ethyl acetate; 3:7), the catalyst was sep-
arated from the reaction mixture by using an external
magnet. The precipitate was filtered off and washed with
ethanol, and the final pure product was obtained and
4.4.4 | 3,3′‐[(4‐(3‐Hydroxypropoxy)‐3‐
methoxyphenyl)methylene]bis(4‐hydroxy‐
2H‐chromen‐2‐one) (3e)
White solid; yield: 84%; m.p. 160–162°C. FT‐IR (KBr) ν
1
1097, 1458, 1613, 1663, 2930, 3074, 3435 cm−1. H‐NMR
1
characterized by FT‐IR, H‐NMR, 13C‐NMR and CHNS
(400 MHz, DMSO‐d6): δ 1.81–1.84 (2H, m, CH2), 3.51–
3.56 (5H, m, CH2‐OH, OCH3), 3.95 (2H, t, J = 6 Hz,
PhO‐CH2), 4.12 (3H, s, OH), 6.26 (1H, s, CH), 6.65 (1H,
d, J = 8 Hz, Ar‐H), 6.71 (1H, s, Ar‐H), 6.80 (1H, d, J = 8
Hz, Ar‐H), 7.30–7.37 (4H, m, Ar‐H), 7.59 (2H, t, J = 8
Hz, Ar‐H), 7.90 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐NMR
(100 MHz, DMSO‐d6): δ 32.26, 35.67, 55.72, 57.42, 65.35,
104.34, 111.68, 112.77, 115.96, 117.91, 118.97, 123.75,
123.86, 131.86, 132.18, 146.52, 148.74, 152.19, 164.71,
165.04 ppm; anal. calcd for C29H24O9: C, 67.44%; H,
4.68%; found: C, 67.22%; H, 4.72%.
analyses. The characterization data for the synthesized
compounds are given below. Also, the NMR spectra are
given in the Supporting Information.
4.4.1 | 3,3′‐[(4‐Methoxyphenyl)methylene]
bis(4‐hydroxy‐2H‐chromen‐2‐one) (3b)
1
White solid; yield: 88%; m.p. 154–156°C. H‐NMR (400
MHz, DMSO‐d6): δ 3.70 (3H, s, OCH3), 6.28 (1H, s, CH),
6.79 (2H, d, J = 12 Hz, Ar‐H), 7.06 (2H, d, J = 8 Hz, Ar‐
H), 7.31–7.38 (4H, m, Ar‐H), 7.60 (2H, t, J = 8 Hz, Ar‐
H), 7.90 (2H, d, J = 8 Hz, Ar‐H) ppm; anal. calcd for
C20H14O7: C, 65.58%; H, 3.85%; found: C, 65.38%; H,
3.90%.
4.4.5 | 3,3′‐[(4‐(2‐Hydroxyethoxy)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3f)
White solid; yield: 87%; m.p. 188–190°C. FT‐IR (KBr) ν
1
1091, 1453, 1614, 1664, 2930, 3074, 3434 cm−1. H‐NMR
4.4.2 | 3,3′‐[(4‐Dimethylaminophenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3c)
(400 MHz, DMSO‐d6): δ 3.68 (2H, t, J = 6 Hz, CH2‐OH),
3.92 (2H, t, J = 6 Hz, PhO‐CH2), 4.73 (3H, br, OH), 6.29
(1H, s, CH), 6.81 (2H, d, J = 12 Hz, Ar‐H), 6.05 (2H, d,
J = 8 Hz, Ar‐H), 7.32–7.39 (4H, m, Ar‐H), 7.61 (2H, t, J
= 8 Hz, Ar‐H), 7.91 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐
NMR (100 MHz, DMSO‐d6): δ 35.27, 59.58, 69.40,
104.44, 114.13, 116.04, 117.61, 123.86, 123.90, 127.80,
131.05, 132.05, 152.16, 156.84, 164.72, 165.84 ppm; anal.
calcd for C27H20O8: C, 68.64%; H, 4.27%; found: C,
68.51%; H, 4.32%.
1
White solid; yield: 85%; m.p. 210–212°C. H‐NMR (400
MHz, DMSO‐d6): δ 3.13 (6H, s, N (CH3)2), 6.28 (1H, s,
CH), 7.21–7.28 (6H, m, Ar‐H), 7.41 (2H, d, J = 12 Hz,
Ar‐H), 7.51 (2H, t, J = 8 Hz, Ar‐H), 7.81 (2H, d, J = 8
Hz, Ar‐H) ppm; anal. calcd for C21H17NO6: C, 71.20%;
H, 4.65%; N, 3.08%; found: C, 70.90%; H, 4.70%; N, 3.00%.
4.4.3 | 3,3′‐[(4‐(3‐Hydroxypropoxy)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3d)
4.4.6 | 3,3′‐[(4‐(2‐Hydroxyethoxy)‐3‐
methoxyphenyl)methylene]bis(4‐hydroxy‐
2H‐chromen‐2‐one) (3g)
White solid; yield: 88%; m.p. 185–188°C. FT‐IR (KBr) ν
1
1089, 1463, 1619, 1671, 2929, 3058, 3443 cm−1; H‐NMR
White solid; yield: 84%; m.p. 150–152°C. FT‐IR (KBr) ν
1
(400 MHz, DMSO‐d6): δ 1.79–1.85 (2H, m, CH2), 3.51–
3.57 (2H, m, CH2‐OH), 3.95–3.98 (2H, m, PhO‐CH2),
4.72 (3H, br, OH), 6.28 (1H, s, CH), 6.80 (2H, d, J = 8
Hz, Ar‐H), 7.05 (2H, d, J = 8 Hz, Ar‐H), 7.32–7.39 (4H,
m, Ar‐H), 7.61 (2H, d, J = 8 Hz, Ar‐H), 7.91 (2H, t, J =
8 Hz, Ar‐H) ppm. 13C‐NMR (100 MHz, DMSO‐d6): δ
1095, 1455, 1614, 1662, 2929, 3075, 3434 cm−1. H‐NMR
(400 MHz, DMSO‐d6): δ 3.56 (3H, s, OCH3), 3.68 (2H, t,
J = 8 Hz, CH2‐OH), 3.90 (2H, t, J = 8 Hz, PhO‐CH2),
5.75 (3H, br, OH), 6.26 (1H, s, CH), 6.64 (1H, d, J = 8
Hz, Ar‐H), 6.72 (1H, s, Ar‐H), 6.81 (1H, d, J = 8 Hz, Ar‐
H), 7.30–7.36 (4H, m, Ar‐H), 7.58 (2H, t, J = 8 Hz, Ar‐

14 of 16
TEIMURI‐MOFRAD ET AL.
H), 7.89 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐NMR (100
MHz, DMSO‐d6): δ 35.68, 55.55, 59.63, 70.16, 104.33,
111.43, 112.82, 115.98, 118.15, 118.89, 123.73, 123.93,
131.83, 132.56, 146.39, 148.69, 152.25, 164.76,
165.40 ppm; anal. calcd for C28H22O9: C, 66.93%; H,
4.41%; found: C, 66.70%; H, 4.50%.
35.69, 52.28, 64.76, 103.48, 115.69, 118.58, 119.01,
123.26, 124.01, 127.93, 131.39, 152.39, 164.57,
166.69 ppm; anal. calcd for C29H23NO7: C, 70.01%; H,
4.66%; N, 2.82%; found: C, 69.81%; H, 4.76%; N, 2.75%.
4.4.10 | 3,3′‐[(4‐(1H‐benzo [d]imidazol‐1‐
yl)phenyl)methylene]bis(4‐hydroxy‐2H‐
chromen‐2‐one) (3k)
4.4.7 | 3,3′‐[(4‐(2‐Bromoethoxy)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3h)
Pink solid; yield: 91%; m.p. 267–269°C. FT‐IR (KBr) ν
1
1031, 1329, 1408, 1609, 1673, 2909, 3159, 3430 cm−1. H‐
Yellow solid; yield: 90%; m.p. 273–275°C. FT‐IR (KBr) ν
NMR (400 MHz, DMSO‐d6): δ 4.25 (2H, br, OH), 6.41
(1H, s, CH), 7.23–7.30 (4H, m, Ar‐H), 7.42 (2H, d, J = 8
Hz, Ar‐H), 7.51–7.63 (7H, m, Ar‐H), 7.77 (2H, d, Ar‐H),
7.84 (2H, d, J = 8 Hz, Ar‐H), 7.92 (1H, d, J = 8 Hz, Ar‐
H(, 9.07 (1H, s, N‐CH=N) ppm. 13C‐NMR (100 MHz,
DMSO‐d6): δ 36.17, 103.05, 112.87, 115.57, 115.79,
119.68, 123.00, 124.12, 124.32, 126.08, 126.28, 130.84,
131.15, 152.54, 164.46, 167.71 ppm; anal. calcd for
C32H20N2O6: C, 72.72%; H, 3.81%; N, 5.30%; found: C,
72.62%; H, 3.90%; N, 5.21%.
1
458, 1085, 1450, 1609, 1667, 2927, 3066, 3434 cm−1. H‐
NMR (400 MHz, DMSO‐d6): δ 4.01–4.03 (2H, m, CH2‐
Br), 4.23 (2H, br, PhO‐CH2), 6.28 (1H, s, CH), 6.82 (2H,
d, J = 12 Hz, Ar‐H), 7.06 (2H, d, J = 8 Hz, Ar‐H), 7.30–
7.37 (4H, m, Ar‐H), 7.59 (2H, t, J = 8 Hz, Ar‐H), 7.88
(2H, d, J = 8 Hz, Ar‐H), ppm. 13C‐NMR (100 MHz,
DMSO‐d6): δ 31.57, 35.27, 66.32, 104.34, 114.11, 115.92,
117.86, 123.72, 123.85, 127.80, 131.69, 131.85, 152.16,
156.43, 164.77, 165.06 ppm; anal. calcd for C27H19BrO7:
C, 60.58%; H, 3.58%; found: C, 60.28%; H, 3.62%.
4.4.11 | 3,3′‐[(4‐(4‐Methylpiperazin‐1‐yl)
phenyl)methylene]bis(4‐hydroxy‐2H‐chro-
men‐2‐one) (3l)
4.4.8 | 3,3′‐[(4‐(2‐Bromoethoxy)‐3‐
methoxyphenyl)methylene]bis(4‐hydroxy‐
2H‐chromen‐2‐one) (3i)
Pink solid; yield: 85%; m.p. 222–224°C. FT‐IR (KBr) ν
1
Yellow solid; yield: 89%; m.p. 125–127°C. FT‐IR (KBr) ν
1036, 1340, 1400, 1607, 1664, 2939, 3054, 3450 cm−1. H‐
1
458, 1096, 1457, 1644, 1658, 2925, 3062, 3453 cm−1. H‐
NMR (400 MHz, DMSO‐d6): δ 2.83 (3H, s, CH3), 3.35
(8H, m, 4CH2), 3.84 (2H, br, OH), 6.19 (1H, s, CH), 6.81
(2H, d, J = 8 Hz, Ar‐H), 6.98 (2H, d, J = 8 Hz, Ar‐H),
7.19–7.26 (4H, m, Ar‐H), 7.49 (2H, d, J = 8 Hz, Ar‐H),
7.79 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐NMR (100 MHz,
DMSO‐d6): δ 35.33, 42.10, 46.23, 52.45, 103.54, 115.43,
115.83, 119.94, 122.82, 124.04, 127.37, 130.82, 134.31,
146.94, 152.46, 164.52, 167.55 ppm; anal. calcd for
C30H26N2O6: C, 70.58%; H, 5.13%; N, 5.49%; found: C,
70.35%; H, 5.23%; N, 5.40%.
NMR (400 MHz, DMSO‐d6): δ 3.57 (3H, s, OCH3), 3.75
(2H, t, J = 8 Hz, CH2‐Br), 3.90 (2H, br, OH), 4.22 (2H, t,
J = 8 Hz, PhO‐CH2), 6.24 (1H, s, CH), 6.64 (1H, d, J = 8
Hz, Ar‐H), 6.72 (1H, s, Ar‐H), 6.81 (1H, d, J = 8 Hz, Ar‐
H), 7.26–7.32 (4H, m, Ar‐H), 7.55 (2H, t, J = 8 Hz, Ar‐
H), 7.86 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐NMR (100
MHz, DMSO‐d6): δ 31.57, 35.71, 55.78, 68.83, 104.03,
111.98, 113.90, 115.77, 118.73, 119.04, 123.41, 123.96,
131.48, 134.45, 145.43, 148.82, 152.31, 164.64, 166.18
ppm; anal. calcd for C28H21BrO8: C, 59.48%; H, 3.74%;
found: C, 59.28%; H, 3.84%.
4.4.12 | 3,3′‐[(4‐(Piperidin‐1‐yl)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3m)
4.4.9 | 3,3′‐[(4‐(Morpholin‐4‐yl)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3j)
Pink solid; yield: 86%; m.p. 170–172°C. FT‐IR (KBr) ν
1027, 1329, 1402, 1612, 1673, 2937, 3054, 3424 cm−1. H‐
1
Pink solid; yield: 85%; m.p. 206–208°C. FT‐IR (KBr) ν
NMR (400 MHz, DMSO‐d6): δ 1.62 (2H, br, CH2), 1.85
(4H, br, 2CH2), 3.43–3.56 (6H, m, OH and 2CH2), 6.30
(1H, s, CH), 7.21–7.28 (6H, m, Ar‐H), 7.48–7.53 (4H, m,
Ar‐H), 7.80 (2H, d, J = 8 Hz, Ar‐H) ppm. 13C‐NMR (100
MHz, DMSO‐d6): δ 20.66, 23.44, 36.00, 56.01, 102.94,
115.56, 119.74, 120.61, 123.00, 124.13, 128.22, 131.14,
1
1077, 1304, 1447, 1613, 1670, 2960, 3043, 3424 cm−1. H‐
NMR (400 MHz, DMSO‐d6): δ 3.42 (4H, s, N (CH2)2),
3.87 (4H, s, O (CH2)2), 6.29 (1H, s, CH), 7.18–7.31 (8H,
m, Ar‐H), 7.54 (2H, t, J = 8 Hz, Ar‐H), 7.84 (2H, d, J =
8 Hz, Ar‐H) ppm. 13C‐NMR (100 MHz, DMSO‐d6): δ

TEIMURI‐MOFRAD ET AL.
15 of 16
[13] M. I. Choudhary, N. Fatima, K. M. Khan, S. Jalil, S. Iqbal,
152.54, 164.45, 167.76 ppm; anal. calcd for C30H25NO6: C,
72.72%; H, 5.09%; N, 2.83%; found: C, 72.55%; H, 5.18%;
N, 2.78%.
Bioorg. Med. Chem. 2006, 14, 8066.
[14] I. Manolov, C. Maichle‐Moessmer, N. Danchev, Eur. J. Med.
Chem. 2006, 41, 882.
[15] G. Appendino, G. Cravotto, S. Tagliapietra, S. Ferraro, G. M.
4.4.13 | 3,3′‐[(4‐(1H‐Imidazol‐1‐yl)phenyl)
methylene]bis(4‐hydroxy‐2H‐chromen‐2‐
one) (3n)
Nano, G. Palmisano, Helv. Chim. Acta 1991, 74, 1451.
[16] A. Sahar, Z. A. Khan, M. Ahmad, A. F. Zahoor, A. Mansha, A.
Iqbal, Trop. J. Pharm. Res. 2017, 16, 203.
[17] V. D. Kancheva, P. V. Boranova, J. T. Nechev, I. I. Manolov,
Pink solid; yield: 93%; m.p. 308–310°C. FT‐IR (KBr) ν
Biochimie 2010, 92, 1138.
1
1043, 1326, 1400, 1610, 1685, 2913, 3148, 3445 cm−1. H‐
[18] J. Li, Y. P. Sui, J. J. Xin, X. L. Du, J. T. Li, H. R. Huo, H. Ma, W.
H. Wang, H. Y. Zhou, H. D. Zhan, Z. J. Wang, C. Li, F. Sui, X.
Li, Bioorg. Med. Chem. Lett. 2015, 25, 5520.
NMR (400 MHz, DMSO‐d6): δ 3.40 (2H, br s, OH), 6.33
(1H, s, CH), 7.21–7.32 (6H, m, Ar‐H), 7.50–7.57 (4H, m,
Ar‐H), 7.79–7.86 (3H, m, Ar‐H), 8.20 (1H, s, CH‐N), 9.56
(1H, s, CH‐N) ppm. 13C‐NMR (100 MHz, DMSO‐d6): δ
106.56, 110.78, 111.97, 112.10, 112.70, 113.97, 115.10,
119.13, 122.09, 123.20, 125.44, 135.42, 143.54, 155.40,
158.79 ppm; anal. calcd for C28H18N2O6: C, 70.29%; H,
3.79%; N, 5.86%; found: C, 70.08%; H, 3.85%; N, 5.80%.
[19] K. M. Khan, F. Rahim, A. Wadood, N. Kosar, M. Taha, S.
Lalani, A. Khan, M. I. Fakhri, M. Junaid, W. Rehman, M.
Khan, S. Perveen, M. Sajid, M. I. Choudhary, Eur. J. Med.
Chem. 2014, 81, 245.
[20] K. M. Khan, S. Iqbal, M. A. Lodhi, G. M. Maharvi, M. I.
Choudhary, S. Perveen, Bioorg. Med. Chem. 2004, 12, 1963.
[21] K. M. Khan, A. Wadood, M. Ali, Z. Ul‐Haq, Z. Ul‐Haq, M. A.
Lodhi, M. Khan, M. Khan, S. Perveen, M. I. Choudhary,
J. Mol. Graphics Modell. 2010, 28, 792.
ACKNOWLEDGEMENT
The authors thank research affairs of the University of
Tabriz for financial support.
[22] O. Talhi, M. Schnekenburger, J. Panning, D. G. Pinto, J. A.
Fernandes, F. A. A. Paz, C. Jacob, M. Diederich, A. M. Silva,
Bioorg. Med. Chem. 2014, 22, 3008.
[23] J. Li, X. Y. Xue, X. Li, Z. Hou, X. H. Yang, D. Qu, Y. Zhou, Z. D.
Zhang, X. X. Luo, J. T. Li, M. K. Li, Arch. Pharmacol. Res. 2016,
39, 1349.
ORCID
Reza Teimuri‐Mofrad
https://orcid.org/0000-0002-5812-
6445
[24] J. Xu, J. Ai, S. Liu, X. Peng, L. Yu, M. Geng, F. Nan, Org.
Biomol. Chem. 2014, 12, 3721.
[25] N. Hamdi, M. C. Puerta, P. Valerga, Eur. J. Med. Chem. 2008,
43, 2541.
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