Sulfuric acid heterogenized on magnetic Fe3O4 nanoparticles: A new and efficient magnetically reusable catalyst for condensation reactions

Article abstract of DOI:10.1002/aoc.3938

Immobilized sulfuric acid on magnetic Fe₃O₄ nanoparticles (Fe₃O₄ MNPs-OSO₃H) as a new solid acid nanocomposite was successfully synthesized and its catalytic activity in a series of condensation reactions was studied. High catalytic activity, simple separation from reaction mixture by an external magnet and good reusability are several eco-friendly advantages of this catalytic system. It is noteworthy that this catalytic system is applicable to a wide range of spectrum of aromatic aldehydes, and the desired products were obtained in good to excellent yields under mild conditions. The use of ecofriendly solvents makes also this synthetic protocol ideal and fascinating from the environmental point of view.

Full text of DOI:10.1002/aoc.3938

Received: 6 February 2017
DOI: 10.1002/aoc.3938
Revised: 24 April 2017
Accepted: 23 May 2017
F U L L PA P E R
Sulfuric acid heterogenized on magnetic Fe3O4 nanoparticles: A
new and efficient magnetically reusable catalyst for condensation
reactions
Lotfi Shiri1 | Setare Zarei1 | Mosstafa Kazemi1
| Davood Sheikh2
1 Department of Chemistry, Faculty of Basic
Sciences, Ilam University, P.O. Box 69315‐
Immobilized sulfuric acid on magnetic Fe3O4 nanoparticles (Fe3O4 MNPs‐OSO3H)
as a new solid acid nanocomposite was successfully synthesized and its catalytic
activity in a series of condensation reactions was studied. High catalytic activity,
simple separation from reaction mixture by an external magnet and good reusability
are several eco‐friendly advantages of this catalytic system. It is noteworthy that this
catalytic system is applicable to a wide range of spectrum of aromatic aldehydes,
and the desired products were obtained in good to excellent yields under mild con-
ditions. The use of ecofriendly solvents makes also this synthetic protocol ideal and
fascinating from the environmental point of view.
516, Ilam, Iran
2 Young Researchers & Elite Club, Hamedan
Branch, Islamic Azad University,
Hammedan, Iran
Correspondence
Lotfi Shiri, Department of Chemistry,
Faculty of Basic Sciences, Ilam University, P.
O. Box 69315‐516, Ilam, Iran.
Email: lshiri47@gmail.com
KEYWORDS
condensation reactions, external magnet, magnetic Fe3O4 nanoparticles, reusable catalyst, sulfuric acid
1 | INTRODUCTION
Furthermore, organic synthesis under aqueous media (with-
out using any toxic and hazardous organic solvent) has
The modern age of organic synthesis is shifting towards the
development of new and efficient synthetic strategies which
principally focus on environmental aspects of chemical or
organic reactions such as the use of green materials and cat-
alysts. During the last decade, organic synthesis clearly expe-
rienced a renaissance in the utilization field of nano materials
as catalyst support[1] In the recent times, magnetic nanoparti-
cles (MNPs) as catalyst support have received lots of atten-
tion due to their high surface area to bulk ratios, the
capability of easy dispersion, the easy separation from reac-
tion media by external magnet, high activity and thermal sta-
bility, and the capability of surface modifications[2–7]
Magnetic nanoparticles (MNPs) have recently considered as
a promising alternative to other catalyst supports, because
they cause not only the process readily perform under mild
conditions but also the target products afford in a fast, effi-
cient and time‐saving manner[8–10] Among the various
employed magnetic NPs as the core magnetic support,
Fe3O4 nanoparticles have been widely studied both for their
scientific interests and technological applications[11,12]
recently received special attention in both academic and
industrial research.[13]
The quinazoline and its analogous are a very important
category of nitrogen‐containing heterocyclic compounds that
are broadly distributed in many natural products and bio‐
active molecules. Among them, 2, 3‐dihydroquinazoline‐
4(1H)‐ones have recognized as a key and supplementary
block in agro‐chemistry, medicinal and organic
chemistry.[14]Besides, 2, 3‐dihydroquinazoline‐4(1H)‐one
derivatives can act as key structural motifs to design the
new category of highly valuable synthetic drug candidates
owing to their important pharmacological properties.[15,16]
Recent literature studies clearly shown that a variety of mol-
ecules containing 2, 3‐dihydroquinazoline‐4(1H)‐one struc-
tural units exhibit a series of significant biological activities
such as antitumor, anticancer, antibiotic, antibacterial,
antidefibrillatory, antipyretic, and anticonvulsant[17–19] The
condensation of aryl, alkyl and hetroaryl aldehydes or
ketones with anthranil amide in the presence of acidic cata-
lysts is a well‐known approach for the synthesis of 2, 3‐
Appl Organometal Chem. 2017;e3938.
wileyonlinelibrary.com/journal/aoc
Copyright © 2017 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.3938

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SHIRI ET AL.
dihydroquinazoline‐4(1H)‐ones.[20] In recent times, a variety
of catalysts and promoter or reagents for the synthesis of
these compounds have been reported in the literature.[21–23]
Despite the profound significance of the reported synthetic
methodologies in organic synthesis, unfortunately, most of
them have a series of notable blind spots such as the use of
expensive and excess amounts of catalyst, toxic and hazard-
ous organic solvents, unsatisfactory yields, harsh reaction
conditions and the formation of by‐products. However,
owing to the significance of 2, 3‐dihydroquinazoline‐4(1H)‐
ones from the biological and pharmaceutical point of views,
the development of novel, clean and versatile synthetic
approaches using stable magnetically recoverable catalysts
under green mediums for the synthesis of 2, 3‐
dihydroquinazoline‐4(1H)‐ones is an important research tar-
get in contemporary organic synthesis.
Catalysis of synthetic reactions by acids is always an
important and fascinating research target in organic syn-
thesis. Since the acids are often liquid and expensive, their
separation from reaction media is the most important con-
cern of synthetic chemist.[24] Therefore, the designing and
synthesizing of strong solid acids and their utilization as
catalyst in synthetic reactions is a nice response of future
of organic synthesis, in particular from the green synthetic
chemistry point of view.[25,26] The immobilization of acids
reagents or functional groups on Fe3O4 MNPs and their
catalytic utilization in organic synthesis, can be considered
an ideal and fascinating solution to overcome this draw-
back because the fabricated acidic catalyst can be readily
separated from the reaction media by external magnet.
Inspired by this theme, in our present research, we wish
to report that the sulfuric acid supported on magnetic
Fe3O4 nanoparticles (Fe3O4 MNPs‐OSO3H) is a stable
and highly efficient catalyst for synthesis of 2,3‐
dihydroquinazoline‐4(1H)‐ones.
2 | RESULT AND DISCUSSION
2.1 | Preparation and characterization of
Fe3O4 MNPs‐OSO3H:
Immobilized diethylenetriamine on magnetic Fe3O4 nanopar-
ticles (Fe3O4 MNPs‐OSO3H catalyst) was successfully syn-
thesized by using the surface modification strategy as
depicted in Scheme 1. The magnetic Fe3O4 nanoparticles
were prepared by chemical co‐precipitation method[1] and
coated with 3‐chloropropyltrimethoxysilane (CPTMS) by
covalent bonds.[1] The reaction of the supported CPTMS
with triethanolamine (TEA) in toluene under reflux condi-
tions for 42 h produced the TEA functionalized magnetic
nanoparticles (Fe3O4 MNPs‐TEA). Finally, the reaction of
Fe3O4 MNPs‐TEA with chlorosulfonic acid in CH2Cl2 at
room temperature gave sulfuric acid supported on magnetic
Fe3O4 nanoparticles (Fe3O4 MNPs‐OSO3H).
As‐fabricated catalyst was comprehensively characterized
by FT‐IR, TGA, XRD, SEM, EDX and VSM, ICP analysis
techniques.
The FT‐IR was used to further confirm the presence of
sulfuric acid moiety on the surface of Fe3O4 nanoparticles.
The FT‐IR spectra for the Fe3O4 MNPs (black line), Fe3O4
MNPs‐CPTMS (red line), Fe3O4 MNPs‐TEA (blue line)
and Fe3O4 MNPs‐OSO3H (green line) are displayed in
Figure 1. The FT‐IR analysis of the Fe3O4 MNPs exhibits a
characteristic peak at 579 cm−1, which is attributed to the
Fe‐O stretching vibration. Also the broad band at around
3400 cm−1 is attributed to bound water O‐H stretching vibra-
tion adsorption. The anchored CPTMS on Fe3O4 MNPs is
confirmed by a characteristic peak at 996 cm−1, which is
attributed to Fe‐O‐Si stretching vibration. As seen on the
curve of Fe3O4 MNPs‐TEA, the functionalized TEA instead
of Cl is confirmed by O–H stretching vibrations that appear
SCHEME 1 Stepwise preparation of
sulfuric acid supported on magnetic Fe3O4
nanoparticles (Fe3O4 MNPs‐OSO3H)

SHIRI ET AL.
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broad peak at 2800–3700 cm−1 is corresponded to the OH
stretching of sulfuric acid group.
The SEM image of Fe3O4 MNPs‐OSO3H was shown that
the catalyst was formed of nanometer‐sized particles
(Figure 2).
The components of the Fe3O4 MNPs‐OSO3H catalyst
were analyzed by using energy‐dispersive X‐ray spectros-
copy (EDX) (Figure 3). As displayed in Figure 3., the charac-
teristic peak of S demonstrated well that the sulfuric acid
successfully immobilized on magnetic Fe3O4 nanoparticles.
The magnetic property of the nanocatalyst was studied by
vibrating sample magnetometer (VSM) at ambient tempera-
ture. The room temperature magnetization curves of Fe3O4
MNPs and Fe3O4 MNPs‐OSO3H were shown in Figure 4.
As shown on Figure 4, the saturation magnetization of
Fe3O4 MNPs‐OSO3H was found to be at about 17 emu/g,
which is much lower than bare Fe3O4 MNPs (about at
55 emu/g). The decrease of the saturation magnetization
can be related to the presence of sulfuric acid groups on the
surface of the Fe3O4 nanoparticles supports.
Thermogravimetric analysis (TGA) was also used to
assess the percentage of functional groups chemisorbed onto
the surface of magnetic Fe3O4 nanoparticles. Figure 5 shows
the TGA curves for bare Fe3O4 MNPs (black line), Fe3O4
MNPs‐CPTMS (green line) and Fe3O4 MNPs‐OSO3H (blue
line). The TGA curve of the all samples shows the small
amount of weight loss below 200°C is due to desorption of
physically adsorbed solvents and surface hydroxyl groups.
Organic groups have been reported to desorb at temperatures
above 260°C. In the curve of Fe3O4 MNPs‐CPTMS (green
line), a weight loss about 5% is observed for Fe3O4 MNPs‐
CPTMS in the temperature range between 260 and 400°C
which it is attributed to the thermal decomposition of Fe3O4
FIGURE 1 FT‐IR spectra of Fe3O4 MNPs (black line) Fe3O4 MNPs‐
CPTMS (red line), Fe3O4 MNPs‐TEA (blue line) and Fe3O4 MNPs‐
OSO3H (green line)
at 3446 cm−1. Also, two weak peaks at 2857 and 2926 were
observed, which are ascribed to the C‐H stretching vibration
of alkyl chain of TEA. As seen on the curve of Fe3O4 MNPs‐
OSO3H, the symmetric and asymmetric stretching modes of
O = S = O were observed at 1033 and 1073 cm−1. Also,
FIGURE 2 SEM images of the Fe3O4 MNPs‐OSO3H

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SHIRI ET AL.
FIGURE 3 EDX spectrum of the Fe3O4 MNPs‐OSO3H
FIGURE 6 The XRD pattern of the Fe3O4 MNPs‐OSO3H
SO3H groups. As the result of this analysis, it can be con-
cluded that the well grafting of sulfuric acid on the Fe3O4
MNPs is verified.
X‐ray diffraction (XRD) is an effective spectra technique
to the better reorganization of the major properties of the
magnetite structures. In fact, the formation of magnetite crys-
tal phase in the nanomagnetic catalyst in aggregate powder
form can be as well identified by the X‐ray diffraction
(XRD). X‐ray diffraction (XRD) spectrum of Fe3O4 MNPs‐
OSO3H is displayed in Figure 6. In the XRD pattern of
Fe3O4 MNPs‐OSO3H, several characteristic peaks at
2θ = 35.2o, 41.3o, 50.5o, 63.2o, 67.4o and 74.5o were
observed, which are assigned to the (220), (311), (400),
(422), (511) and (440) crystallographic faces of magnetite
(in good agreement with the standard Fe3O4 XRD spectrum
reported in literature).[9] This analysis clearly affirmed this
theme that the surface modification and conjugation of the
Fe3O4 nanoparticles did not lead to phase change.[9]
FIGURE 4 Magnetization curves for Fe3O4 MNPs (blue line) and
Fe3O4 MNPs‐OSO3H (red line) at room temperature
The sulfuric acid loading on the surface of magnetic
nanoparticles was determined by back acid–base titration
analysis. The data obtained by back titration showed that
the loading amount of sulfamic acid is 0.9 mmolg−1
.
2.2 | Catalytic studies
2.2.1 | 2, 3‐dihydroquinazolin‐4(1H)‐ones
After characterization of the catalyst, the catalytic activity
of sulfuric acid supported on magnetic Fe3O4 nanoparticles
(Fe3O4 MNPs‐OSO3H) for the cyclocondensation of
anthranilamide with various aldehydes or ketones was
investigated. In preliminary experiment, to understand the
efficiency of catalyst in the synthesis of 2, 3‐
dihydroquinazoline‐4(1H)‐ones, the condensation of benz-
aldehyde and anthranilamide was tested in the presence
of Fe3O4 MNPs‐OSO3H (10 mg) in water at reflux
FIGURE 5 TGA curves of Fe3O4 MNPs (black line), Fe3O4 MNPs‐
CPTMS (green line) and Fe3O4 MNPs‐OSO3H (blue line)
MNPs‐OSO3H the 3‐chloropropyl silane groups. In the curve
of Fe3O4 MNPs‐OSO3H, a weight percentage loss about 26%
over the range of 160–420°C is also observed, which is
attributed to the thermal decomposition of organic and

SHIRI ET AL.
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a
TABLE 1 Optimization of the reaction conditions
Entry
Catalyst (mg)
Solvent (Temp.oC)
H2O (reflux)
Time (min)
Yield (%)b
1
2
15
15
15
15
15
5
45
30
83
67
81
81
96*
82
88
94
93
89
CH3CN (reflux
DMF (reflux)
3
130
65
4
H2O: EtOH (1:1)(80 °C)
EtOH (reflux)
5
25
6
EtOH (reflux)
50
7
10
20
15
15
EtOH (reflux)
35
8
EtOH (reflux)
25
9
EtOH (70 °C)
35
10
EtOH (60 °C)
50
aReaction conditions: 1.05 mmol of anthranilamide and 1 mmol of 1a in the presence of catalyst and solvent (2 ml).
bIsolated yield.
temperature. It was observed that the process was con-
ducted smoothly to produce the product 3a in 83% after
45 min (Table 1, Entry 1). Then, to optimize the reaction
conditions, the condensation of benzaldehyde and
anthranilamide was chosen as a model reaction and the
effect of solvents, catalyst loading and reaction temperature
on the process was investigated. First, under catalytic
amount of Fe3O4 MNPs‐OSO3H (15 mg), the effect of sol-
vent on the process was investigated. The model reaction
were performed in a series of solvents such as CH3CN,
DMF, H2O: EtOH (1:1) and EtOH at reflux temperature
(Table 1, Entry 2–5). As sown in Table 1, the best results
(highest yield and shortest time) were observed in EtOH
(Table 1, Entry 5). After found the best solvent, the effect
of catalyst loading and temperature on the model reaction
was studied (Table 1, Entry 6–10). These experiments
revealed that the 15 mg Fe3O4 MNPs‐OSO3H catalyst
gives the best results (with respect to product yields and
reaction times) for the formation of product 3a. Then, the
effect of reaction temperature on the model substrate was
investigated (Table 1, Entry 9–10). As shown in Table 1,
these experiments revealed that the 15 mg Fe3O4 MNPs‐
OSO3H catalyst in refluxing EtOH is the optimal reaction
conditions (Table 1, Entry 5).
In order to study the scope and generality of the catalytic
system, a nice category of aldehydes and ketones was sub-
jected to the reaction with anthranilamide under the opti-
mized reaction conditions (Scheme 2). The results are listed
in Table 2. As shown in Table 2, when electron‐donating or
electron‐withdrawing groups were on para position of the
aromatic ring (Table 2, Entry 2–10), the yields were excellent
and reaction times were shorter than ortho and meta positions
SCHEME 2 Cyclocondensation of anthranilamide with aldehydes/
ketones (1) catalyzed by Fe3O4 MNPs‐OSO3H
(Table 2, Entry 11–15). Likewise, ketones such as cyclohex-
anone and acetophenone also afforded the desired products
2q and 2r respectively, in admirable yields.
2.2.2 | Knoevenagel condensation
On the other hand, the Knoevenagel condensation is one
of the most recognized carbon–carbon bond forming reac-
tions in organic chemistry. The Knoevenagel products,
namely the α,β ‐unsaturated products or synthesized
alkenes, have been broadly employed as intermediates in
the synthesis of fine chemical,[30] therapeutic drugs,[31]
natural products,[32] functional polymers,[33] cosmetics,[34]
perfumes,[35] hetero Diels‐Alder reactions[36] and in the
synthesis of carbocyclic as well as heterocyclic com-
pounds of biological significance.[37] Owing to the signif-
icance of Knoevenagel products from the biological and
medicinal point of views, we decided to study the cata-
lytic activity of Fe3O4 MNPs‐OSO3H in the Knoevenagel
condensation of aldehydes and active methylene com-
pounds. In this respect, the condensation of malononitrile
with 4‐chlorobenzaldehyde was chosen as the model

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SHIRI ET AL.
TABLE 2 Fe3O4 MNPs‐OSO3H catalyzed the one‐pot synthesis of 2, 3‐dihydroquinazolin‐4(1H)‐ones in EtOH at reflux temperature
Entry
1
R
R’
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
‐‐‐
Me
Product
2a
Time (min)
Yield (%)a
96
Mp (oc) [ref.]
198–200[19]
185‐‐186[19]
221–223[19]
196–198[19]
199–201[27]
202–203[19]
170–172[15]
209–211[27]
276–278[19]
217–219[15]
191–192[28]
190–191[28]
184–186[27]
145–147[19]
188–190[29]
203–205[19]
174–175[19]
185–187[28]
C6H5CHO
25
40
40
45
75
50
50
80
50
25
30
75
30
60
30
40
95
80
2
4‐OMeC6H5CHO
4‐MeC6H5CHO
4‐FC6H5CHO
2b
90
3
2c
93
4
2d
96
5
4‐NO2C6H5CHO
4‐BrC6H5CHO
4‐EtOC6H5CHO
4‐(Me2)NC6H5CHO
4‐OHC6H5CHO
4‐ClC6H5CHO
3‐NO2C6H5CHO
3‐BrC6H5CHO
3‐OHC6H5CHO
2‐NO2C6H5CHO
2‐ClC6H5CHO
3,4‐(OMe)2C6H5CHO
Cyclohexanone
Ph
2e
90
6
2f
92
7
2 g
2 h
2i
91
8
93
9
92
10
11
12
13
14
15
16
17
18
2j
94
2 k
2 l
91
92
2 m
2n
90
94
2o
96
2p
90
2q
89
2r
92
aIsolated yield.
substrate to screen the optimal reaction conditions and the
results are summarized in Table 3. After extensive experi-
ments, 10 mg of Fe3O4 MNPs‐OSO3H catalyst in
refluxing water was considered as the optimized reaction
conditions for further investigation (Table 3, Entry 6).
The generality of this catalytic system was then evaluated
by reaction of various aldehydes and active methylene
compounds (namely malononitrile and ethyl cynoacetate)
under the standardized conditions (Scheme 3). The collected
results are listed in Table 4. As shown in Table 4, aromatic
aldehydes substituted with either electron‐donating or elec-
tron‐withdrawing groups the reacted readily with
malononitrile and ethyl cynoacetate, and the desired products
were obtained in satisfactory to excellent yields. Unlike
a
TABLE 3 Optimization of the reaction conditions
Entry
Catalyst (mg)
Solvent (Temp.oC)
CH2Cl2 (reflux)
CH3CN (reflux)
n‐hexane (reflux)
EtOH (reflux)
Time/min
240
240
240
75
Yield (%)b
1
10
10
10
10
10
10
3
45
60
50
81
90
97*
92
94
96
95
91
2
3
4
5
H2O: EtOH (1:1)(80 °C)
H2O (reflux)
30
6
12
7
H2O (reflux)
25
8
5
H2O (reflux)
20
9
15
10
10
H2O (reflux)
12
10
11
H2O (90 °C)
20
H2O (80 °C)
35
aReaction conditions: 1.05 mmol of and 1 mmol of 3a in the presence of catalyst and solvent (3 ml).
bIsolated yield.

SHIRI ET AL.
7 of 13
First, the effect of catalyst loading was evaluated in the
solvent‐free reaction at 80°C (Table 5, Entries 1–5). The
yield was greatly affected by the amount of catalyst
loaded. The comparison of the results related to the effect
of various amounts of catalyst revealed that the highest
activity was observed in the presence of 40 mg of catalyst
(Table 5, Entry 4).
The model reaction was tested then in a series of custom-
ary solvents such as THF, CH3CN, EtOH, H2O and under
solvent‐free conditions at 80°C (Table 5, Entry 4). As shown
in Table 5, the highest yield (97%) and shortest time (30 min)
for the product 6a was observed under thermal solvent‐free
conditions (Table 5, Entry 4). Next, under the standardized
catalyst amount, the effect of temperature on the solvent‐free
reaction was checked. Higher reaction temperature (90°C)
did not provide a significantly better yield, but with a lower
reaction temperature (r.t, 60 and 70°C), the yield was
decreased (Table 5, Entries 10–12). Finally, the reaction
proceeded very slowly in the absence of catalyst and only a
trace of desired product was found after heating for more than
2 h (Table 5, Entry 13). Accordingly, on the basis of the
above experiments, 40 mg of the catalyst (Fe3O4 MNPs‐
OSO3H) was considered for the synthesis of
polyhydroquinoline derivatives under solvent‐free conditions
at 80°C (Table 5, Entry 4).
With the optimized reaction conditions in hand, to
evaluate the scope and limitation of this catalytic system,
a diverse range of aromatic aldehydes was subjected to
reaction with ethyl acetoacetate, dimedone and ammonium
acetate (Scheme 4). The collected results are illustrated in
Table 6. As shown in Table 6, all products were obtained
in excellent yields. It is noteworthy that the type of alde-
hyde has no significant effect on the reaction, because the
SCHEME 3 Knoevenagel condensation (KC) of active methylene
compounds with aromatic aldehydes catalyzed by Fe3O4 MNPs‐OSO3H
malononitrile (Table 3, Entry 1–12), when ethyl cynoacetate
considered as substrate (Table 3, Entry 13–16), the desired
products 4 k–n were afforded in lower yields and longer
reaction times.
2.2.3 | Polyhydroquinolines
Polyhydroquinolines are an important of nitrogen‐contain-
ing heterocyclic compounds that have attracted profound
attention due to their significant biological and pharmaco-
logical activities such as antidiabetic, hepatoprotective,
vasodilator, geroprotective, antiatherosclerotic, bronchodila-
tor, anticancer and antitumor.[44–46] Considering these
valuable medicinal applications, we decided to study the
catalytic activity of Fe3O4 MNPs‐OSO3H for the synthesis
of Polyhydroquinolines. Initially, to find out optimum
reaction conditions and understand the effect of various
parameters (such as solvent type, catalyst loading and tem-
perature) on four‐component reactions, the reaction of 4‐
chlorobenzaldehyde (5a), ethyl acetoacetate, dimedone
and ammonium acetate was chosen as model reaction.
TABLE 4 Fe3O4 MNPs‐OSO3H catalyzed the one‐pot Knoevenagel condensation in water at reflux temperature
Entry
1
Substrate
4‐ClC6H5CHO
4‐OMeC6H5CHO
4‐MeC6H5CHO
4‐FC6H5CHO
4‐NO2C6H5CHO
4‐BrC6H5CHO
C6H5CHO
X/Y
Cn/Cn
Product
4a
Time (min)
Yield (%)a
Mp (oc) [ref.]
159–161[38]
110–111[38]
129–132[38]
122–123[39]
158–160[38]
156–158[40]
81–83[38]
12
15
97
95
87
85
90
92
91
85
88
90
89
90
85
80
2
Cn/Cn
4b
3
Cn/Cn
4c
10
4
Cn/Cn
4d
15
5
Cn/Cn
4e
12
6
Cn/Cn
4f
15
7
Cn/Cn
4 g
4 h
4i
10
8
3‐NO2C6H5CHO
2‐NO2C6H5CHO
2‐ClC6H5CHO
4‐ClC6H5CHO
4‐FC6H5CHO
4‐BrC6H5CHO
4‐MeC6H5CHO
Cn/Cn
55
104–106[40]
139–141[41]
94–96[42]
9
Cn/Cn
60
10
11
12
13
14
Cn/Cn
4j
15
CN/CO2Et
CN/CO2Et
CN/CO2Et
CN/CO2Et
4 k
4 l
110
125
115
145
90–93[40]
80–90[43]
4 m
4n
89–91[40]
91–92[40]
aIsolated yield.

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SHIRI ET AL.
a
TABLE 5 Optimization of the reaction conditions
Entry
Catalyst (mg)
Solvent
Solvent‐free
Solvent‐free
Solvent‐free
Solvent‐free
Solvent‐free
CH3CN
Temperature (°C)
Time (min)
Yield (%) b
1
10
20
30
40
50
40
40
40
40
40
40
40
‐‐‐
80
80
100
85
60
30
25
80
80
80
80
60
40
30
120
90
92
2
3
80
95
4
80
97*
97
5
80
6
Reflux
Reflux
Reflux
Reflux
60
60
7
THF
40
8
H2O
50
9
EtOH
75
10
11
12
13
Solvent‐free
Solvent‐free
Solvent‐free
Solvent‐free
91
70
94
90
95
80
Trace
aReactions conditions: 5a (1 mmol), dimedone (1 mmol), ethyl acetoacetate (1 mmol) and ammonium acetate (1.2 mmol).
bIsolated yield.
desired products were obtained in high yields in relatively
short reaction times.
of Fe3O4 MNPs‐OSO3H was investigated in these reactions.
The synthesis of products 2a, 4a and 6a under the optimized
reaction conditions was considered as the model reactions.
Accordingly, after the first fresh run, the catalyst was readily
separated from reaction mixture by an external magnet. The
recovered catalyst was washed several times with ethyl ace-
tate and dried to remove residual product. Then, the
In order to show the high potential of present synthetic
protocol, the collected results for the synthesis of products
2j, 4a and 6a was compared with the reported previously pro-
cedures in the literature (Table 7). As shown in Table 7, this
catalytic system is superior to some of the reported previ-
ously procedures in terms of reaction conditions, reaction
time and percentage yields.
TABLE 6 Fe3O4 MNPs‐OSO3H catalyzed the synthesis of
polyhydroquinolines at 80 °C under solvent‐free conditions
2.2.4 | Reusability of the catalyst
Time Yield
Mp (oc)
[ref.]
Entry
Aldehyde
Product (min) (%)a
The recovery and reusability of catalyst is an important
aspect in catalytic processes. In this respect, the reusability
1
4‐ClC6H5CHO
4‐MeC6H5CHO
4‐FC6H5CHO
4‐NO2C6H5CHO
4‐BrC6H5CHO
4‐OMeC6H5CHO
C6H5CHO
6a
6b
6c
30
25
15
40
20
15
35
30
45
15
50
97
91
96
92
98
98
94
96
95
93
94
230–233[47]
257–268[47]
187–189[47]
240–241[48]
251–254[47]
180–182[47]
202–204[47]
229–231[48]
171–173[48]
205–207[48]
205–207[48]
2
3
4
6d
6e
5
6
6f
7
6 g
6 h
6i
8
3‐BrC6H5CHO
3‐NO2C6H5CHO
2‐ClC6H5CHO
2‐NO2C6H5CHO
9
10
11
6j
6 k
SCHEME 4 Fe3O4 MNPs‐OSO3H catalyzed the synthesis of
polyhydroquinolines
aIsolated yield.

SHIRI ET AL.
9 of 13
TABLE 7 Comparison of the activity of various catalysts in the synthesis of products 2j (Entries 1–5), 4a (Entries 6–10) and 6a (Entries 11–15)
Entry
1
Catalyst
KAl(SO4)2.E12H2O
Glycerosulfonic acid
Silica sulfuric acid
Silica sulfuric acid
Fe3O4 MNPs‐OSO3H
PVC‐tepa
Condition
EtOH, reflux
Time (min)
300
360
180
240
25
Yield (%)
80
[ref.]
[49]
[50]
[51]
[52]
2
Glycerol, 80 °C
H2O,80 °C
97
3
81
4
Solvent‐free, 80 °C
EtOH, reflux
80
5
94
This work
[53]
6
EtOH, reflux
60
90
7
SO4−2/ZrO2
Solvent‐free, reflux
DMSO, 35 °C
Acetone, r.t
120
720
60
88
[54]
[55]
[38]
8
Lipase
94
9
NP‐SnO2
95
10
11
12
13
14
15
Fe3O4 MNPs‐OSO3H
PdCl2
H2O, reflux
12
97
This work
[55]
THF, reflux
240
30
87
[56]
[57]
[58]
K7[PW11CoO40
Cu‐SPATB/Fe3O4
[TBA]2[W6O19
Fe3O4 MNPs‐OSO3H
]
CH3CN, reflux
Peg‐400, 80 °C
Solvent‐free, 110 °C
Solvent‐free, 80 °C
80
65
98
]
20
95
30
97
This work
recovered catalyst was reused for a subsequent fresh batch of
the reaction. The collected results well demonstrated that the
catalyst was readily recovered and reused at least for six runs
without significant loss of catalytic activity in terms of reac-
tion yield (Figure 7).
The leaching of the supported catalyst was evaluated
by back acid–base titration analysis. It was found that
there is not any significance difference in the loading
amount of acid group the surface of magnetic nanoparti-
cles after six times.
3 | CONCLUSION
In summary, sulfuric acid supported on magnetic nanoparti-
cles (Fe3O4 MNPs‐OSO3H) is successfully prepared by a mul-
tiple synthetic strategy which characterized by FT‐IR, TGA,
XRD, SEM, EDX and VSM analysis techniques. The catalytic
activity of this new solid acid nanocomposite was studied in
the one pot synthesis of 2,3‐dihydroquinazoline‐4(1H)‐ones,
polyhydroquinolines and Knoevenagel condensation of active
methylene compounds with various aldehydes. It is notewor-
thy that this catalytic system is applicable to a broad spectrum
of aromatic aldehydes and ketones, and the desired products
were obtained in satisfactory to excellent yields. The fascinat-
ing futures of catalytic system are simplicity operation, cleaner
reaction, use of reusable catalyst, simple workup, simple
separation and the reusability of nanomagnetic catalyst as well
as the ability to tolerate a broad range of substations in the
aromatic aldehydes.
4 | EXPERIMENTAL
4.1 | Materials
Chemicals were purchased from Fisher and Merck. The
reagents and solvents used in this work were obtained
from Sigma‐Aldrich, Fluka or Merck and used without
FIGURE 7 Reusability of Fe3O4 MNPs‐OSO3H in the synthesis of
products 2a, 4a and 6a

10 of 13
SHIRI ET AL.
further purification. The infrared spectra (IR) of samples
were recorded in KBr disks using a NICOLET impact
410 spectrometer. 1HNMR and 13CNMR spectra were
recorded with a Bruker DRX‐400 spectrometer at 400
and 100 MHz respectively. Nanostructures were character-
to remove the unattached substrates. The resulting product
was dried at room temperature.
4.5 | Preparation of sulfuric acid‐
functionalized magnetic Fe3O4 nanoparticles
(Fe3O4 MNPs‐OSO3H)
The Fe3O4 MNPs–TEA (0.5 g) was dispersed in CH2Cl2
(10 ml) using an ultrasonic bath for 20 min. Then,
chlorosulfonic acid (1.5 mL) was added dropwise over a
period of 20 min, and the mixture was stirred for 3 h at
room temperature. Functionalized Fe3O4 MNPs were sepa-
rated by magnetic decantation, washed four times with dry
CH2Cl2 and two times with EtOH, and dried at room
temperature.
ized using
a
Holland Philips X, pert X‐ray
powder diffraction (XRD) diffractometer (Co Kα, radia-
tion = 0.154056 nm), at a scanning speed of 2° min−1
from 10° to 80°. Scanning electron microscope (SEM)
was performed on a FEI Quanta 200 SEM operated at a
20 kV accelerating voltage. The thermogravimetric analy-
sis (TGA) curves are recorded using a PL‐STA 1500
device manufactured by Thermal Sciences. The magnetic
measurements were carried out in a vibrating sample mag-
netometer (VSM, BHV‐55, Riken, Japan) at room
temperature.
4.6 | General procedure for the synthesis of
2,3‐dihydroquinazolin‐4(1H)‐ ones
4.2 | Preparation of the magnetic Fe3O4‐
nanoparticles
A mixture of anthranilamide (1.05 mmol, 142 mg), alde-
hyde or ketone and Fe3O4 MNPs‐OSO3H (15 mg) in eth-
anol (2 ml) was stirred at reflux temperature. Reaction
progress was monitored by TLC (acetone: n‐hexane,
2:8). After time specified in Table 2, reaction mass was
allowed to cool down to room temperature. CH2Cl2
(3 × 5 ml) was added to reaction mixture and the catalyst
was separated by an external magnet. CH2Cl2 was evapo-
rated under reduced pressure to afford the crude products.
The obtained crude products were further recrystallized
from ethanol to get the pure 2, 3‐dihydroquinazolin‐
4(1H)‐ones in 89–96% yields.
The mixture of FeCl3 .6H2O (5.838 g, 0.0216 mol) and
FeCl2.4H2O (2.147 g, 0.0108 mol) were dissolved in
100 mL of deionized water in a three‐necked bottom
(250 ml) under N2 atmosphere. After that, under rapid
mechanical stirring, 10 ml of NH3 was added into the
solution within 30 min with vigorous mechanical stirring.
After being rapidly stirred for 30 min, the resultant black
dispersion was heated to 80°C for 30 min. The black pre-
cipitate formed was isolated by magnetic decantation,
washed with double‐distilled water until neutrality, and
further washed twice with ethanol and dried at room
temperature.
4.7 | General procedure for Knoevenagel
condensation
4.3 | Preparation of Fe3O4 MNPs‐CPTMS
The obtained Fe3O4 nanoparticles (1.5 g) was dispersed in
250 ml ethanol/water (volume ratio, 1:1) by sonication for
30 min, and then CPTMS (2.5 ml) was added to the mixture
reaction. The reaction mixture was stirred using mechanical
stirring under N2 atmosphere at 40°C for 8 h. then, the nano-
particles was redispersed in ethanol by sonication for 5 times
and separated through magnetic decantation. The nanoparti-
cles product (Fe3O4 MNPs‐CPTMS) was dried at room
temperature.
A mixture of aldehyde (1 mmol), activated methylene com-
pounds (1.05 mmol) and Fe3O4 MNPs‐OSO3H (10 mg) in
water (2 ml) was stirred at reflux temperature. Reaction prog-
ress was monitored by TLC (acetone: n‐hexane, 3:7). After
time specified in Table 4, reaction mass was allowed to cool
down to room temperature. Ethyl acetate (3 × 5 ml) was
added to reaction mixture and the catalyst was separated by
an external magnet. Ethyl acetate was evaporated under
reduced pressure to afford the crude products. The obtained
crude products were further recrystallized from ethanol to
get the pure final products (80–97%).
4.4 | Preparation of Fe3O4 MNPs‐TEA
The prepared Fe3O4 MNPs‐CPTMS (1.5 g) were dispersed in
toluene (50 ml) by ultrasonic bath for 10 min.
Triethanolamine (TEA) (2 mL) was added and stirred at
100°C for 30 h under N2 atmosphere. Then, the prepared
functionalized magnetic nanoparticles were separated by
magnetic decantation and washed three times with ethanol
4.8 | General procedure for the synthesis of
polyhydroquinolines
A mixture of aldehyde (1 mmol), dimedon (1 mmol),
ethylacetoacetate (1 mmol), ammonium acetate (1.2 mmol)
and Fe3O4 MNPs‐OSO3H (40 mg) was stirred at 80°C under

SHIRI ET AL.
11 of 13
solvent‐free conditions. Reaction progress was monitored by
TLC (acetone: n‐hexane, 3:7). After completion of the reac-
tion, the catalyst was separated using an external magnet
and washed with ethyl acetate. Then, the solvent was evapo-
rated and all products were recrystallized from ethanol. The
pure polyhydroquinoline derivatives were obtained in excel-
lent yields (91–98%).
4.9.4 | 2‐(4‐Chlorobenzylidene)malononitrile
(4a):
1H NMR (400 MHz, DMSO‐d6): δH = 7.74 (d, J = 8.8 Hz,
2H), 7.97 (d, J = 8.8 Hz, 2H), 8.73 (s, 1H). 13C–NMR
(100 MHz, DMSO) δC = 82.7, 113.5 (CN), 114.5 (CN),
115.7 (2C), 130.5, 132.6 (2C), 139.5, 160.6.
4.9.5 | Ethyl (E)‐2‐Cyano‐3‐(4‐methylphenyl)‐
2‐propenoate (4p):
4.9 | Spectroscopic data
1H NMR (400 MHz, DMSO‐d6) δH
=
1.26 (t,
All the products reported here are known compounds and the
spectroscopic data was matched literature values. Data for the
some of the compounds are given below.
J = 7.2 Hz, 3H), 2.4 (S, 3H), 3.54 (q, J = 7.2 Hz, 2H)
7.1 (d, J = 8 Hz, 2H), 7.45–7.47 (d, J = 8 Hz, 2H),
8.03 (s, 1H). 13C–NMR (100 MHz, DMSO‐d6) δC = 15.24
(CH3), 55.31 (CH3O), 65.39 (O‐CH2), 102.33 (C‐CN),
113.77 (CN), 121.36, 126.51, 132.22, 139.33, 152.57,
162.26 (C = O).
4.9.1 | 2‐phenyl‐2,3‐dihydroquinazolin‐4(1H)‐
one (2a):
1H NMR (400 MHz, DMSO‐d6): δH = 5.77 (s, 1H), 6.69
(t, J = 8 Hz, 1H, Ar‐H), 6.77 (d, J = 7.6 Hz, 1H, Ar‐H),
7.13 (brs, 1H, N‐H), 7.26 (td, J = 8, 1.6 Hz, 1H, Ar‐H),
7.34–7.43 (m, 3H, Ar‐H), 7.51 (dd, J = 6.8, 1.2 Hz, 2H,
Ar‐H), 7.63 (dd, J = 7.6, 1.2 Hz, 1H, Ar‐H), 8.31 (brs,
1H, N‐H). 13C NMR (100 MHz, DMSO‐d6) δC = 67.1,
114.9, 115.4, 117.6, 127.4, 127.9, 128.8, 129, 133.8,
142.1, 148.4, 164.1.
4.9.6 | Ethyl‐4‐(4‐Fluoro‐phenyl)‐2,7,7‐
trimethyl‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐
3‐carboxylate (6c)
1H NMR (400 MHz, DMSO‐d6) δH = 0.85 (s, 3H), 1.02
(s, 3H), 1.13 (t, J = 7.2 Hz, 3H), 1.99 (d, J = 16 Hz,
1H), 2.18 (d, J = 16 Hz, 1H), 2.28–2.32 (m, 4H), 2.43
(d, J = 16.8 Hz, 1H), 3.98 (q, J = 7.2 Hz, 2H), 4.87
(s, 1H), 6.99–7.20 (m, 4H, Ar‐H), 9.11 (brs, 1H, N‐H).
13C NMR (100 MHz, DMSO‐d6) δC = 14.6, 18.8, 26.7,
29.6, 32.6, 35.8, 39.8, 50.7, 59.5, 74.32, 103.9, 110.4,
114.7, 129.6, 144.3, 145.7, 149.95, 159.71–162.11
(JCF = 240 HZ), 167.2, 194.7.
4.9.2 | 2‐(4‐Chlorophenyl)‐2,3‐
dihydroquinazolin‐4(1H)‐one (2j):
1H NMR (400 MHz, DMSO‐d6): δH = 5.79 (s, 1H), 6.70 (t,
J = 7.6 Hz, 1H, Ar‐H), 6.76 (d, J = 8 Hz, 1H, Ar‐H), 7.16
(brs, 1H, N‐H), 7.24–7.29 (td, J = 7.6, 1.6 Hz, 1H, Ar‐H),
7.46–7.49 (dt, J = 8.8, 2 Hz, 2H, Ar‐H), 7.51–7.53 (dt,
J = 8.4, 2 Hz, 2H, Ar‐H), 7.62 (dd, J = 7.6, 1.6 Hz, 1H,
Ar‐H), 8.35 (brs, 1H, N‐H). 13C NMR (100 MHz, DMSO‐
d6) δC = 66.3, 114.9, 115.4, 117.8, 127.9, 128.8, 129.2,
133.5, 133.9, 141.1, 148.1, 164.
4.9.7 | Ethyl‐4‐phenyl‐2,7,7‐trimethyl‐5‐oxo‐
1,4,5,6,7,8‐hexahydroquinoline‐3‐carboxylate
(6 g)
1H NMR (400 MHz, DMSO‐d6) δH = 0.86 (s, 3H), 1.02 (s,
3H), 1.14 (t, J = 7.2 Hz, 3H), 1.99 (d, J = 16 Hz, 1H),
2.18 (d, J = 16 Hz, 1H), 2.29–2.33 (m, 4H), 2.44 (d,
J = 17.2 Hz, 1H), 3.99 (q, J = 7.2 Hz, 2H), 4.88 (s, 1H),
7.06–7.21 (m, 5H, Ar‐H), 9.07 (brs, 1H, N‐H). 13C NMR
(100 MHz, DMSO‐d6) δC = 14.6, 18.8, 26.9, 29.6, 32.6,
36.4, 50.7, 59.5, 104.1, 110.5, 126.1, 127.9, 128.2, 145.5,
148.1, 150, 167.3, 194.7.
4.9.3 | 2‐(3‐Nitrophenyl)‐2,3‐
dihydroquinazolin‐4(1H)‐one (2 k):
1H NMR (400 MHz, DMSO‐d6): δH = 5.98 (s, 1H), 6.72 (t,
J = 8 Hz, 1H, Ar‐H), 6.82 (d, J = 8 Hz, 1H, Ar‐H), 7.29
(td, J = 6.8, 1.6 Hz, 1H, Ar‐H), 7.38 (brs, 1H, N‐H), 7.65
(dd, J = 8, 1.6 Hz, 1H, Ar‐H), 7.71 (t, J = 8 Hz, 1H, Ar‐
H), 7.97 (d, J = 7.6 Hz, 1H, Ar‐H), 8.23 (dq, J = 8,
1.6 Hz, 1H, Ar‐H), 8.39 (t, J = 2 Hz, 1H, Ar‐H), 8.57
((brs, 1H, N‐H). 13C NMR (100 MHz, DMSO‐d6) δC = 65.7,
115.1, 115.4, 118, 122.1, 123.8, 127.9, 130.5, 133.8, 134.1,
144.7, 147.8, 148.2, 163.9.
4.9.8 | Ethyl‐4‐(3‐Bromo‐phenyl)‐2,7,7‐
trimethyl‐5‐oxo‐1,4,5,6,7,8‐hexahydroquinoline‐
3‐carboxylate (6 h)
1H NMR (400 MHz, DMSO‐d6) δH = 0.87 (s, 3H), 1.03 (s,
3H), 1.14 (t, J = 7.2 Hz, 3H), 2.01 (d, J = 16 Hz, 1H),
2.19 (d, J = 16 Hz, 1H), 2.31–2.34 (m, 4H), 2.45 (d,

12 of 13
SHIRI ET AL.
[23] M. Ghashang, S. S. Mansoor, K. Aswin, Res. Chem. Intermed.
2013, 6168, 695.
J = 17.2 Hz, 1H), 4.0 (q, J = 7.2 Hz, 2H), 4.85 (s, 1H), 7.15–
7.31 (m, 4H, Ar‐H), 9.16 (brs, 1H, N‐H). 13C NMR
(100 MHz, DMSO‐d6) δC = 14.6, 18.8, 26.8, 29.6, 32.6,
36.6, 50.6, 59.6, 103.5, 109.9, 121.5, 127, 129, 130.6,
130.9, 146.1, 150.3, 150.7, 167, 194.8.
[24] N. Koukabi, E. Kolvari, M. A. Zolfigol, A. Khazaei, B. S.
Shaghasemi, B. Fasahatib, Adv. Synth. Catal. 2012, 354, 2001.
[25] S. Rostamnia, A. Nuri, H. Xin, A. Pourjavadi, S. H. Hosseini, Tet-
rahedron Lett. 2013, 54, 3344.
[26] J. Safari, Z. Zarnega, J. Mol. Catal. A: Chem. 2013, 379, 269.
ACKNOWLEDGEMENTS
[27] A. Ghorbani‐Choghamarani, H. Goudarziafshar, P. Zamani, Chin.
Chem. Lett. 2011, 22, 1207.
This work was supported by the research facilities of Ilam
University, Ilam, Iran.
[28] J.Safari,S.Gandomi‐Ravandi,J.Mol.Catal.A:Chem.2014,390,1.
[29] V. B. Labade, P. V. Shinde, M. S. Shingare, Tetrahedron Lett. 2013,
54, 5778.
REFERENCES
[30] F. Freeman, Chem. Rev. 1980, 80, 329.
[1] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Appl.
Organometal. Chem. 2016, https://doi.org/10.1002/aoc.3596.
[31] G. A. Kraus, M. E. Krolski, J. Org. Chem. 1986, 51, 3347.
[32] L. F. Tietze, N. Rackelmann, Pure Appl. Chem. 2004, 76, 196.
[2] L. Zhang, P. Li, C. Liu, J. Yang, M. Wang, L. Wang, Catal. Sci.
Technol. 2014, 4, 1979.
[33] F. Liang, Y.‐J. Pu, T. Kurata, J. Kido, H. Nishide, Polymer 2005,
46, 3767.
[3] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Appl.
Organometal. Chem. 2016, https://doi.org/10.1002/aoc.3596.
[34] F. Bigi, L. Chesini, R. Maggi, G. Sartori, J. Org. Chem. 1999, 64,
[4] X. Zhang, P. Li, Y. Ji, L. Zhang, L. Wang, Synthesis 2011, 2975.
1033.
[5] L. Shiri, S. Rahmati, Z. Ramezani‐Nejad, M. Kazemi, Appl.
Organomet. Chem. 2017, https://doi.org/10.1080/10426507.2016.
1224878.
[35] N. Yu, J. M. Aramini, M. W. Germann, Z. Huang, Tetrahedron
Lett. 2000, 41, 6993.
[36] I. Kim, S. G. Kim, J. Choi, G. H. Lee, Tetrahedron 2008, 64,
[6] L. Zhang, P. Li, H. Li, L. Wang, Catal. Sci. Technol. 2012, 2, 1859.
664.
[7] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Res. Chem.
Intermed. 2017, 43, 2707.
[37] L. F. Tietze, Chem. Rev. 1996, 96, 115.
[38] H. Sharghi, S. E. Moghaddam, R. Memarzadeh, S. Javadpour,
[8] L. Zhang, P. Li, J. Yang, M. Wang, L. Wang, Chem. Plus. Chem.
2014, 79, 217.
J. Iran. Chem. Soc. 2013, 10, 141.
[39] J. P. Sonawane, S. B. Chaudhari, S. S. Patil, M. V. Sonawane, Int. J.
Phys. Sci. 2015, 4, 60.
[9] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Monatsh. Chem.
2017, https://doi.org/10.1007/s00706‐016‐1906‐4.
[40] L. Muralidhar, C. R. Girija, J. Saudi. Chem. Soc. 2014, 18, 541.
[41] M. L. Kantam, B. Bharathi, Catal. Lett. 1998, 55, 235.
[42] R. Pal, T. Sarkar, Int. J. Org. Chem. 2014, 4, 106.
[10] L. Shiri, M. Kazemi, Res. Chem. Intermed. 2017, https://doi.org/
10.1007/s11164‐017‐2914‐7.
[11] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Aust. J. Chem.
2016, 69, 585.
[43] G. Li, J. Xiao, W. Zhang, Green Chem. 2012, 14, 2234.
[44] M. Saha, A. K. Pal, Tetrahedron Lett. 2011, 52, 4872.
[12] L. Shiri, A. Ghorbani‐Choghamarani, M. Kazemi, Aust. J. Chem.
2017, 70, 9.
[45] K. A. Undale, T. S. Shaikh, D. S. Gaikwad, D. M. Pore, C R
Chimie. 2011, 14, 511.
[13] M. Kazemi, H. Kohzadi, O. Abdi, J. Mater. Environ. Sci. 2015, 6,
1451.
[46] K. Sirisha, G. Achaiah, V. M. Reddy, Arch. Pharm. 2010, 343,
[14] A. Davoodnia, S. Allameh, A. R. Fakhari, N. Chin. Chem. Lett.
2010, 21, 550.
342.
[47] A. Ghorbani‐Choghamarani, B. Tahmasbi, P. Moradi, N. Havasi,
Appl. Organomet. Chem. 2016, 30, 619.
[15] A. GhorbaniChoghamarani, G. Azadi, RSC Adv. 2015, 5, 9752.
[16] A. Ghorbani‐Choghamarani, P. Zamani, J Iran Chem Soc 2012, 9,
[48] M. Tajbakhsh, H. Alinezhad, M. Norouzi, S. Baghery, M. Akbari,
607.
J. Mol. Liq. 2013, 177, 44.
[17] A. Ghorbani‐Choghamarani, M. Norouzi, J. Mol. Catal. A: Chem.
2014, 395, 172.
[49] M. Dabiri, P. Salehi, S. Otokesh, M. Baghbanzadeh, G. Kozehgary,
A. A. Mohammadi, Tetrahedron Lett. 2005, 46, 6123.
[18] J. Safari, S. Gandomi‐Ravandi, C R Chimie 2013, 16, 1158.
[19] A. Rostami, A. Tavakoli, Chin. Chem. Lett. 2011, 22, 1317.
[50] M. Hajjami, F. Bakhti, E. Ghiasbeygi, Croat. Chem. Acta 2015, 88,
197.
[51] S. Bonollo, D. Lanari, L. Vaccaro, Eur. J. Org. Chem. 2011, 14,
[20] K. Niknam, N. Jafarpour, E. Niknam, Chin. Chem. Lett. 2011,
22, 69.
2587.
[52] F. Dong, Y. Q. Li, R. F. Dai, Chin. Chem. Lett. 2007, 18, 266.
[21] B.‐H. Chen, J.‐T. Li, G.‐F. Chen, Ultrason. Sonochem. 2015,
23, 59.
[53] B. M. Reddy, M. K. Patil, K. N. Rao, G. K. Reddy, J. Mol. Catal.
A: Chem. 2006, 258, 302.
[22] M. Abdollahi, A. E. Shabani, J. Iran. Chem. Soc. 2014, 11, 351.

SHIRI ET AL.
13 of 13
[54] Y. Ding, X. Ni, M. Gu, S. Li, H. Huang, Y. Hu, Catal. Commun.
2015, 64, 101.
How to cite this article: Shiri L, Zarei S, Kazemi M,
Sheikh D. Sulfuric acid heterogenized on magnetic
Fe3O4 nanoparticles: A new and efficient magnetically
reusable catalyst for condensation reactions. Appl
Organometal Chem. 2017;e3938. https://doi.org/
10.1002/aoc.3938
[55] M. Saha, A. K. Pal, Tetrahedron Lett. 2011, 52, 4872.
[56] M. M. Heravi, K. Bakhtiari, N. M. Javadi, F. F. Bamoharram, M.
Saeedi, J. Mol. Catal. A: Chem. 2007, 264, 50.
[57] A. Ghorbani‐Choghamarani, B. Tahmasbi, P. Moradi, N. Havasi,
Appl. Organomet. Chem. 2016, 30, 619.
[58] A. Davoodnia, M. Khashi, N. Tavakoli‐Hoseini, Chin. J. Catal.
2013, 34, 1173.