Heterogeneous SO3H@Fe3O4 magnetic nanocatalyst as an efficient and reusable medium for the synthesis of 3,3′-(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-methane, and 1,8-dioxo-octahydroxanthene derivatives

Article abstract of DOI:10.1002/jccs.202000087

This work aimed to synthesize a new heterogeneous catalyst (SO₃H@Fe₃O₄ magnetic nanoparticles) and the study of its catalytic behavior in synthesizing 3,3′-(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-methane, an

Full text of DOI:10.1002/jccs.202000087

Received: 2 March 2020
Revised: 8 May 2020
Accepted: 19 May 2020
DOI: 10.1002/jccs.202000087
A R T I C L E
Heterogeneous SO H@Fe O magnetic nanocatalyst as an
3
3 4
efficient and reusable medium for the synthesis of
0
3
,3 -(arylmethylene)-bis-(4-hydroxycoumarin),
bis-(indolyl)-methane, and 1,8-dioxo-octahydroxanthene
derivatives
1
2
Xiaobo Wu | Wan-Xi Peng
1
Experimental Center, School of Business,
Abstract
Lingnan Normal University, Zhanjiang,
China
This work aimed to synthesize a new heterogeneous catalyst (SO H@Fe O
3 4
3
2
School of Forestry, Henan Agricultural
magnetic nanoparticles) and the study of its catalytic behavior in synthesizing
University, Zhengzhou, China
0
3
,3 -(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-methane, and
,8-dioxo-octahydroxanthene derivatives. The characterization of obtained
1
Correspondence
Xiaobo Wu, Experimental Center, School
of Business, Lingnan Normal University,
Zhanjiang 524048, China.
material has been performed by means of Fourier-transform infrared spectros-
copy, thermogravimetric analysis, X-ray diffraction, vibrating sample magne-
tometer, and transmission electron microscopy. The main properties of this
new methodology, compared to earlier ones, are the short times of reaction,
mild reaction conditions, simple recovery of the catalyst by permanent mag-
netic field, excellent yields, and reusability of the catalyst for a minimum of
six runs.
Email: fangchang1359@163.com
K E Y W O R D S
heterogeneous catalyst, nanoparticles, reusability of the catalyst, transmission electron
microscopy
[
9]
1
| INTRODUCTION
and disorders of the nervous system. A great number of
supported nanocatalysts can be isolated by centrifugation
or filtration, which result in the loss of catalysts in a large
number of organic transformations. To solve this prob-
lem, magnetic nanoparticles have arisen as efficient novel
supports for functionalization as magnetic nanoparticle-
supported catalysts are isolated from the reaction solu-
In recent years, the use of nanoparticles has received
great attention from scientific researchers as key points
of green technique in the development of sustainable
[1–3]
protocols.
Nanoparticles have many considerable
applications because of their potent physical and chemi-
cal features, including support for bonding with homoge-
nous catalysts, drug delivery, and extraction of heavy and
[
10,11]
tion by an appropriate magnet.
Iron oxide magnetic
nanoparticles (MNPs) for the immobilization of the
organic groups onto a surface with a strong connection
are most interesting because of their easy synthesis and
functionalization, high surface area, good stability, and
[4–8]
harmful ions from wastewater.
They have important
outcomes regarding site-specific drug targeting due to
their biological and pharmaceutical characteristics for
treating different diseases such as HIV infection, cancer,
[
12–14]
low toxicity and price.
Because of their strong
©
2020 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J Chin Chem Soc. 2020;1–20.
http://www.jccs.wiley-vch.de
1

2
WU AND XI PENG
magnetic moments, these nanoparticles show different
types of potential applications in drug delivery, cell
sorting, hyperthermal agents, and Magnetic resonance
2 | RESULTS AND DISCUSSION
2.1 | Fourier transform infrared
spectroscopy analysis of
SO H@Fe O MNPs
[15–20]
imaging contrast agents.
Heterocyclic compounds, also called heterocycles, are
extremely spread across nature and are essential for living
organisms. Coumarins as one of the main groups of hetero-
cycles have attracted interest because they exhibit a variety
of biological properties, such as anti-HIV, antibacterial,
3
3 4
The infrared spectra of the Fe O , Fe O @PC,
3
4
3 4
Fe O @Car, and SO H@Fe O MNP and recovered
3
4
3
3 4
SO H@Fe O
3 4
MNP samples in the region of
3
−
1
anticancer, anti-Hepatitis
C
virus, and antitumor
400–4,000 cm are represented in Figure 1. In the Fe O
spectrum, the stretching vibration of the Fe O bond
appears at 575 cm , while the band at the 3,394 cm
3
4
[21–25]
activities.
In addition, they are utilized as important
0
−1
−1
intermediates in the production of biscoumarins. 3,3 -
(
arylmethylene)-bis-(4-hydroxycoumarins) as the bridge-
region can be related to the stretching vibrations of the
water molecule OH bonds. Furthermore, the band that
appeared at 1,619 cm− is ascribed to the bending vibra-
tions relating to the water molecule HO H bonds. In the
substituted dimers of coumarin were also applied as anti-
fungals, antipyretics, anti-inflammatories, anticoagulants,
antiseptics, and as urease inhibitors.
techniques that have been improved for synthesizing this
kind of biscoumarins, the simplest method that was
improved is based on condensing aldehydes with couma-
rins. For this purpose, a variety of catalysts has been utilized
to facilitate this reaction.
tant class of heterocycles. The broad scope of pharmaceuti-
cal and biological activities of these heterocyclic compounds
1
[26–28]
Among various
−1
spectrum of Fe O @PC, the band at 2,925 cm can be
3 4
attributed to the aliphatic C H group stretching vibra-
−
1
tion. The absorption band that appeared at 1,038 cm
(Si O group) illustrates an efficient immobilization of
the Fe O MNP surface. The bands at 1,393 and
[29–32]
Indoles are another impor-
3
4
1,634 cm− are attributable to the COO and N H (NH )
1
−
2
vibrations and indicate that the Fe O is functionalized
3
4
have
been
illustrated,
such
as
antitumor,
with l-Carnosine. In the spectrum of SO H@Fe O
3 3 4
MNPs, the absorption peaks at the 1,400–1,600 cm
−
1
antihyperlipidemic, antileishmanial, and anticancer
activities.
ing this kind of compounds is on the basis of condensing
aldehydes with indoles. Therefore, a variety of catalysts and
reagents, including PEG-SO H,
[33–36]
The main synthetic procedure for synthesiz-
region can be indexed to the stretching vibration of the
C C bond. The absorption bands at 1,072 and
1,142 cm− are related to the stretching vibration
1
[
37]
[38]
I ,
sulfamic
corresponding to the SO H groups. Finally, the spectrum
3
2
3
[
39]
+
− [40]
acid,
nitrate,
ZrOCl ꢀ8H O,
(PhCH PPh ) Br ,
[hmim]HSO acidic ionic liquid,
ceric ammonium
of recovered SO H@Fe O MNPs after the third recovery
2
3
3
3
3 4
[
41]
[42]
and
and reuse do not show any significant difference.
4
[
43]
has been improved. 1,8-Dioxo-
2
2
octahydroxanthenes are very desirable as a type of het-
erocycle because of their biological and pharmaceutical
[
44]
potential, such as luminescent sensors,
namic therapy,
inflammatory activities,
metics.
photody-
[
45]
[46]
fluorescent materials,
anti-
[
47]
and pigments and cos-
[
48]
Several methodologies for the production of
xanthenedione derivatives over various catalysts, such
[
49]
[50]
as sulfamic acid,
FeCl /[bmim][BF ],
sulfuric acid
3
51]
4
[
+3
[52]
or hydrochloric acid,
amberlyst-15,
dodecylbenzenesulfonic acid,
Fe
montmorillonite,
[
53]
[54]
[55]
SmCl3,
HClO ꢀSiO ,
p-
4
2
[
56]
trimethylsilyl chloride
[
57]
[58]
(
TMSCl),
and InCl /ionic liquid,
were studied in
3
the literature. Although all of the above-mentioned
methods provide an improvement, most of them suffer
from disadvantages, such as requiring expensive
reagents, longer reaction time, hazardous organic sol-
vents, tedious workup, and harsh reaction conditions.
Accordingly, it is important to find more efficient cata-
lysts with reusability and easy isolation with minimal or
no waste for the synthesis of these kinds of compounds.
3 4 3 4
FIGURE 1 FT-IR spectra corresponding to Fe O , Fe O @PC,
Fe O @Car, SO H@Fe O MNPs, and recovered
3
4
3
3 4
SO
3
H@Fe
3
O
4
MNPs

WU AND XI PENG
3
2.2 | Thermal analysis of
SO H@Fe O MNPs
3
3 4
The modification of the Fe O surface was also investi-
3
4
gated by thermogravimetric analysis (TGA) analysis.
TGA thermograms of Fe O , Fe O @PC, and
3
4
3 4
SO H@Fe O MNPs are demonstrated in Figure 2. Fe O
3 4
3
3
4
ꢁ
shows a slight weight loss in the temperature of 250 C,
which is related to the evaporation of the adsorbed H O
2
molecules. Fe O @PC shows a thermal constancy up to
3
4
ꢁ
3
50 C, which is related with the loss of
-chloropropyltriethoxysilane presented on the support
3
of Fe O4 magnetic nanoparticles. SO H@Fe O MNPs
3
3
3 4
have two mass loss steps; the first weight loss is up to
ꢁ
2
00 C, which is associated with the evaporation of H O
2
FIGURE 3 Magnetization curves corresponding to Fe
SO H@Fe MNPs
3 4
O and
from the related Fe O surface, and the second weight
3
4
ꢁ
3
3 4
O
loss is up to 600 C, related to decomposing functionalized
groups on the Fe O surface.
3
4
2.4 | UV/Vis analysis of
SO H@Fe O MNPs
3
3 4
2.3 | Vibrating sample magnetometer
analysis of SO H@Fe O MNPs
UV/Vis spectrum was another type of tool that was uti-
lized to confirm the structure of the SO H@Fe O MNPs
3
3 4
3
3 4
[
59]
Magnetization measurements of prepared SO H@Fe O
3 4
as a catalyst.
This analysis was used to compare
3
MNPs were taken using the vibrating sample magnetom-
eter (VSM) technique, and outcomes are given in
changes in different steps of catalyst preparation. Conse-
quently, it was observed that there are differences in the
absorption maximum between the catalyst structure of
SO H@Fe O MNPs with Fe O , and this is a confirma-
Figure 3. The magnetization saturation values of Fe O4
3
and SO H@Fe O MNPs were 60.48 and 38.74 emu/g,
3
3
4
3
3
4
3 4
respectively. The value of SO H@Fe O MNPs is compar-
tion of the synthesis of this catalyst. As demonstrated in
3
3 4
atively smaller than that of Fe O , which showed the
Figure 4, λmax related to SO H@Fe O MNPs emerges at
3
4
3
3 4
presence of the functional groups loaded on the Fe O4
surface.
about 218 nm. Thereby, changes in the steps of catalyst
preparation, which relate to the alterations in the λmax
value, as well as changes in the curves, demonstrate that
the SO H@Fe O MNPs are constructed.
3
3
3 4
FIGURE 2 TGA thermogram of Fe
SO H@Fe MNPs
3
O
4
, Fe
3
O
4
@PC, and
3 3 4
FIGURE 4 UV absorption curves of SO H@Fe O MNPs as a
catalyst
3
3
O
4

4
WU AND XI PENG
3 4 3 4
FIGURE 5 XRD patterns of Fe O , Fe O @PC/Car and
SO H@Fe O MNPs
3 3 4
2
.5 | X-ray diffraction analysis of
SO H@Fe O MNPs
3 3 4
FIGURE 6 TEM image of SO H@Fe O MNPs
3
3 4
The X-ray diffraction (XRD) method as an efficient spec-
tra method for the better identification of the main fea-
tures of the Fe O , Fe O @PC/Car, and SO H@Fe O
3 4
0
3,3 -(arylmethylene)-bis-(4-hydroxycoumarin) derivatives.
In order to control the experiment and optimize the reac-
tion conditions, the reaction between 4-hydroxycoumarin
1 (2 mmol) and 4-chlorobenzaldehyde 2g (1 mmol) to
form the relating product was chosen as a model reac-
tion, and the various conditions, including solvent type,
catalyst level, and temperature, were examined. The col-
lected results from these experiments were shown in
Table 1. In an initial investigation, the impact of solvent
type (CH CN, THF, acetone, H O, EtOH) on the model
3
4
3
4
3
MNPs is presented in Figure 5. The XRD patterns of the
ꢁ
Fe O4 show six characteristic peaks at 2θ = 31.06 ,
3
3
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
6.11 , 43.61 , 53.35 , 57.87 , and 63.77 , which are
related to the (220), (311), (400), (422), (511), and (440)
[60]
planes,
pattern
SO H@Fe O MNPs exhibit similar diffraction peaks
respectively. In addition, the high-angle XRD
corresponding to Fe O @PC/Car and
3
4
3
3 4
relating to the spinel phase of magnetic iron oxide
nanoparticles.
3
2
reaction at a certain concentration of the catalyst was
screened under reflux conditions (Table 1, Entries 1–5).
As can be seen, the appropriate performance of the prod-
2
.6 | Transmission electron microscopy
analysis of SO H@Fe O MNPs
uct was achieved when H O was used (Table 1, Entry 4).
3
3
4
2
Although the obtained results for H O in the optimal
2
As can be seen from the transmission electron micros-
condition were satisfactory and venerable, the absence of
the solvent was observed to be superior in terms of rate
and yield for this synthesis (Table 1, Entry 9). To identify
the ideal temperature, the model reaction was studied in
several temperatures (such as 25, 60, 70, 80, 90, and
copy (TEM) image shown in Figure 6, the dark Fe O4
3
MNPs cores were almost spherical in shape, with a nar-
row size distribution and with average sizes of 45 nm.
In continuation of surveys on the synthesis of new
[61–64]
ꢁ
catalysts in performing organic reactions,
we
100 C) at a certain concentration of the catalyst (Table 1,
ꢁ
decided to report the efficient and rapid production of
Entries 6–11). The reaction in 25, 60, and 70 C only gave
0
3
,3 -(arylmethylene)-bis-(4-hydroxycoumarin),
bis-
product in low-to-good yields of 32, 65, and 86%, respec-
(
indolyl)-methane, and 1,8-dioxo-octahydroxanthene
tively (Table 1, Entries 6–8). By enhancing the reaction
ꢁ
derivatives using a lower loading of the SO H@Fe O
temperature to 80 C, the performance of the product
3
3
4
MNPs under solvent-free conditions (Scheme 1).
increased sharply (Table 1, Entry 9). When the reaction
was performed at 90 and 100 C (Table 1, Entries 10–11),
the performances were slightly inferior to the results at
ꢁ
First, we focused our attention on evaluating the effi-
ciency of the SO H@Fe O MNPs in the production of
3
3 4

WU AND XI PENG
5
SCHEME 1 Production of
0
3
,3 -(arylmethylene)-bis-
(
4-hydroxycoumarin), bis-(indolyl)-
methane, and 1,8-dioxo-
octahydroxanthene derivatives using
3 3 4
SO H@Fe O MNPs
TABLE 1
one-pot reaction of 4-hydroxycoumarin
1) and 4-chlorobenzaldehyde (2g)
under various conditions
Optimization of the
a
Entry
Solvent
CH CN
Catalyst (mg)
Temp.
Reflux
Reflux
Reflux
Reflux
Reflux
Time (min)
Yield (%)
42
1
2
3
4
5
6
7
8
9
3
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
10/SO
20/SO
—
3
3
3
3
3
3
3
3
3
3
3
3
3
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
3
3
3
3
3
3
3
3
3
3
3
3
3
O
O
O
O
O
O
O
O
O
O
O
O
O
4
4
4
4
4
4
4
4
4
4
4
4
4
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
80
120
120
80
(
THF
35
Acetone
39
H
2
O
76
EtOH
70
54
ꢁ
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
25 C
15
32
ꢁ
60 C
15
65
ꢁ
70 C
15
86
ꢁ
80 C
15
95
ꢁ
10
11
12
13
14
15
16
17
90 C
15
93
ꢁ
100 C
15
91
ꢁ
80 C
15
83
ꢁ
80 C
15
92
ꢁ
80 C
120
15
Trace
81
ꢁ
15/Fe
15/Fe
15/Fe
3
O
4
4
4
@PC
@car
@PC/car
80 C
ꢁ
3
3
O
O
80 C
15
83
ꢁ
80 C
15
87
Note: Reaction conditions: 4-hydroxycoumarin (2 mmol), 4-chlorobenzaldehyde (1 mmol), and required amount of the catalysts.
a
The yields represent the separated product.
ꢁ
8
0 C. Next, to evaluate the impact of catalyst loading on
performed in the absence of the catalyst under the opti-
mized conditions, the yield of the product fell sharply,
and an insignificant product spot was observed on thin-
layer chromatography (TLC; Table 1, Entry 14). Finally,
to compare the effectiveness of the SO H@Fe O MNPs
with catalyst precursors (Table 1, Entries 9 and 15–17),
we use the outcomes for the catalyst precursors in the
production of 3g as a model reaction. The results clearly
exhibit the superiority of the prepared catalyst under
solvent-free condition in saving energy, time, and high
product yields.
the reactivity, the model reaction was carried out at vari-
ous catalyst concentrations (Table 1, Entries 9 and
2–13). As observed in Table 1, the best result in terms of
1
the reaction time and product yield was achieved as the
catalyst concentration was 15 mg. At 10 mg of
SO H@Fe O MNPs, the reaction speed was slow, and
3
3 4
3
3 4
the yield was good (Table 1, Entry 12). However, no sig-
nificant improvement on the yield was observed when
the reaction was performed with 20 mg of the catalyst
(
Table 1, Entry 13). When the model reaction was

6
WU AND XI PENG
0
3 3 4
Preparation of 3,3 -(arylmethylene)-bis-(4-hydroxycoumarin) derivatives using SO H@Fe O MNPs as a catalyst
TABLE 2
ꢁ
ꢁ
M.P (lit) ( C)
Entry
1
RCHO (2)
Product
Time (min)
Yield (%)
M.P (Obsd) ( C)
65
10
92
93
95
229–231
230–232
198–200[
234–236[
6
6]
2
3
25
15
201–203
232–234
65]
66]
4
10
96
231–233
233–235[
6
6]
5
6
30
15
92
93
200–202
229–231
201–203[
228–230[
65]
67]
7
15
95
255–258
252–254[
6
5]
8
9
10
30
92
93
269–271
253–255
265–267[
250–252[
68]

WU AND XI PENG
7
TABLE 2 (Continued)
ꢁ
ꢁ
M.P (lit) ( C)
Entry
RCHO (2)
Product
Time (min)
Yield (%)
M.P (Obsd) ( C)
2
6]
1
0
10
94
195–197
193[
2
6]
1
1
1
2
10
10
96
95
229–234
253–255
236[
2
6]
238[
6
5]
1
1
1
3
4
5
10
15
10
93
96
94
248–250
243–245
195–197
246–248[
240–242[
69]
2
6]
196[
6
8]
1
1
6
7
15
10
90
95
272–275
269–272
ꢁ
271–273[
269–271[
68]
3 3 4
Note: Reaction conditions: 4-hydroxycoumarin (2 mmol), aldehyde (1 mmol), and SO H@Fe O MNPs (15 mg) at 80 C.

8
WU AND XI PENG
a
TABLE 3
Optimizing the one-pot
Entry
Solvent
CH CN
Catalyst (mg)
Temp.
Reflux
Reflux
Reflux
Reflux
Reflux
Time (min)
Yield (%)
45
reaction of indole (4) and
-chlorobenzaldehyde (2f) under
diverse conditions
1
2
3
4
5
6
7
8
9
3
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
10/SO
3
3
3
3
3
3
3
3
3
3
3
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
3
3
3
3
3
3
3
3
3
3
3
O
O
O
O
O
O
O
O
O
O
O
4
4
4
4
4
4
4
4
4
4
4
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
50
70
65
12
15
5
4
THF
39
Acetone
41
H
2
O
83
EtOH
73
ꢁ
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
25 C
32
ꢁ
60 C
5
72
ꢁ
70 C
5
85
ꢁ
80 C
5
93
ꢁ
10
11
12
13
14
15
16
17
90 C
5
92
ꢁ
100 C
5
89
ꢁ
5/SO
3
H@Fe
3
O
4
MNPs
MNPs
80 C
5
85
ꢁ
15/SO
3
H@Fe
3
O
4
80 C
5
92
ꢁ
—
80 C
120
15
15
15
Trace
81
ꢁ
10/Fe
10/Fe
10/Fe
3
O
4
4
4
@PC
@car
80 C
ꢁ
3
3
O
O
80 C
83
ꢁ
@PC/car
80 C
87
Note: Reaction conditions: indole (2 mmol), 4-chlorobenzaldehyde (1 mmol), and required amount of the catalysts.
a
The yields represent the separated product.
After optimizing the reaction conditions and to assess
the scope and generality of this catalytic system, we
explored the protocol with a range of appropriate alde-
performed with a variety of readily available substrates
using SO H@Fe O MNPs under optimal conditions. For
3
3 4
this purpose, a variety of aromatic aldehydes with
electron-withdrawing and electron-donating groups were
reacted with indole, and the relating bis-(indolyl)-
methane derivatives were achieved in very good yields
and times (Table 4, entries 1–18).
0
hydes to prepare a series of 3,3 -(arylmethylene)-bis-
(4-hydroxycoumarin) derivatives (3a-q) under the opti-
mum conditions. The results of this study are shown in
Table 2. As shown, a broad spectrum of aromatic alde-
hydes containing electron-withdrawing and electron-
donating groups in the ortho, meta, and para positions of
the aromatic ring, which were successfully subjected to a
similar reaction, and the above-mentioned products were
achieved in short times with high-to-excellent isolated
yields (Table 2, Entries 1–17).
After successfully synthesizing a set of bis-(indolyl)-
methane derivatives in high-to-excellent yields, we
focused our study on the synthesis of 1,8-dioxo-
octahydroxanthene derivatives. To screen the reaction
conditions for the above-mentioned synthesis, a system-
atic investigation considering different variables affecting
the reaction performance was conducted on the reaction
of dimedone (6) and 4-chlorobenzaldehyde (2d) (molar
ratio: 2:1), used as the model reaction. The outcomes are
shown in the Table 5. The initial optimization experi-
ments demonstrated that, without using SO H@Fe O
After the successful application of SO H@Fe O
3
3 4
0
MNPs as a heterogeneous catalyst in synthesizing 3,3 -
arylmethylene)-bis-(4-hydroxycoumarin) derivatives, we
(
decided to use it in condensing indole with aldehydes,
leading to bis-(indolyl)-methane derivatives. To achieve
this goal and in order to obtain the optimum reaction
conditions, the reaction between indole 4 (2 mmol) and
3
3 4
MNPs, the desired product 7d was not created (Table 5,
Entry 1). In the next phase of the survey, the impacts of
4
-chlorobenzaldehyde 2f (1 mmol) and its resulting prod-
different solvents, such as EtOH, CH CN, toluene, ben-
3
uct was studied as a model reaction in different condi-
tions. The outcomes were shown in Table 3. As can be
seen, the best outcome was attained using 10 mg of
zene, and solvent-free conditions, were evaluated on the
completion of the reaction (Table 5, Entries 2–5 and 9).
The optimization experiments revealed that the highest
yield (98%) was attained when solvent-free conditions
were used in the model reaction (Table 5, Entry 9). Then,
the impact of temperature on the completion of the reac-
tion was evaluated (Table 5, Entries 6–12). It was
ꢁ
SO H@Fe O MNPs as the catalyst at 80 C under
3
3 4
solvent-free conditions (Table 3, Entry 9).
Subsequently, to investigate the efficiency and the
appropriateness of this procedure, condensation was

WU AND XI PENG
9
TABLE 4
3 3 4
Synthesis of bis-(indolyl)-methane derivatives using SO H@Fe O MNPs as a catalyst
Time
(min)
Yield
(%)
M.P
(Obsd) ( C)
M.P
(lit) ( C)
1
2
ꢁ
ꢁ
Entry RCHO (2)
1
R
R
Product
[
38]
H
H
H
H
H
H
8
8
5
92
91
95
148–150
150–152
138–140
219–221
[
68]
2
3
139–141
220–223
[
70]
[
70]
4
H
H
5
96
232–235
222–224
[
70]
5
6
H
H
H
H
12
90
93
80–82
77–79
75–76
75–77
[
71]
5
[
68]
7
8
H
H
H
H
8
91
92
109–111
184–187
110–112
[72]
10
195
(
Continues)

10
WU AND XI PENG
TABLE 4 (Continued)
Time
(min)
Yield
(%)
M.P
(Obsd) ( C)
M.P
(lit) ( C)
1
2
ꢁ
ꢁ
Entry RCHO (2)
9
R
R
Product
[
70]
H
H
15
94
185–189
183–185
[
73]
1
1
0
1
H
H
45
90
123–126
101–103
124–125
[
68]
H
H
H
H
H
H
10
15
20
92
92
89
100–102
201–203
[
70]
1
1
2
3
201–204
192–195
[
74]
194
[
43]
1
1
4
5
CH
CH
3
H
H
6
5
93
97
249–252
240–242
250–253
241–243
[
43]
3

WU AND XI PENG
11
TABLE 4 (Continued)
Time
(min)
Yield
(%)
M.P
(Obsd) ( C)
M.P
(lit) ( C)
1
2
ꢁ
ꢁ
Entry RCHO (2)
R
R
Product
[
70]
16
17
18
CH
CH
CH
3
H
H
H
5
94
95
90
249–251
247–248
213–215
270–272
[
68]
3
5
210–212
269–271
[
75]
3
10
ꢁ
3 3 4
Note: Reaction conditions: indole (2 mmol), aldehyde (1 mmol), and SO H@Fe O MNPs (10 mg) at 80 C.
observed that the maximum yield was obtained when
the desired product were attained by increasing the reac-
tion time. According to the above results, the importance
of SO H@Fe O MNPs as a heterogeneous magnetic
nanocatalyst was revealed in this study, and therefore, it
was selected as an extremely effective catalyst to carry
out this reaction by various derivatives.
ꢁ
9
0 C temperature was used when performing the reac-
tion under solvent-free conditions (Table 5, Entry 9).
Decreasing the temperature caused a smaller yield of the
desired product (Table 5, Entries 6–8), while increasing
3
3 4
ꢁ
the temperature required for the reaction to 120 C did
not affect the reaction time and the product yield
After optimizing the reaction conditions, the perfor-
mance and versatility of the SO H@Fe O MNPs as a het-
(
Table 5, Entries 10–12). As shown, the best outcome was
3
3 4
obtained when the reaction was performed with 15 mg of
the catalyst at 90 C (Table 5, Entry 9). It should be men-
erogeneous magnetic nanocatalyst for synthesizing
1,8-dioxo-octahydroxanthene derivatives were evaluated
by various aromatic aldehydes carrying both different
electron-donating and electron-withdrawing groups, and
in all studied cases, the desired products were obtained in
high-to-excellent yields after appropriate reaction times.
The outcomes are shown in Table 6.
ꢁ
tioned that, by enhancing the catalyst concentration, the
reaction rate became slower (Table 5, Entry 14). In addi-
tion, by decreasing the amount of the catalyst, the reac-
tion time became longer, which resulted in the increase
of the energy consumption (Table 5, Entry 13). Finally,
the effects of the Fe O @PC, Fe O @Car, and
In a plausible mechanism (Scheme 2), initially, inter-
mediate 8 is obtained as a result of a nucleophilic attack
of dimedone 6 on the activated carbonyl group of alde-
hyde 2 in the existence of SO H@Fe O MNPs. After
3
4
3 4
Fe O @PC/Car on the reaction time and the efficiencies
3
4
of the desired product were assessed (Table 5, Entries
5–17). Using the catalyst precursors, the good yields of
1
3
3 4

12
WU AND XI PENG
a
TABLE 5
one-pot reaction of dimedone (6) and
-chlorobenzaldehyde (2d) under
various conditions
Optimization of the
Entry
Solvent
Solvent-free
EtOH
Catalyst (mg)
Temp.
Time (min)
Yield (%)
Trace
72
ꢁ
1
2
3
4
5
6
7
8
9
—
90 C
120
60
60
60
60
60
20
15
10
15
15
15
15
15
15
15
15
4
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
15/SO
10/SO
20/SO
3
3
3
3
3
3
3
3
3
3
3
3
3
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
H@Fe
3
3
3
3
3
3
3
3
3
3
3
3
3
O
O
O
O
O
O
O
O
O
O
O
O
O
4
4
4
4
4
4
4
4
4
4
4
4
4
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
MNPs
Reflux
Reflux
Reflux
Reflux
CH
3
CN
34
Toluene
56
Benzene
45
ꢁ
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
25 C
39
ꢁ
70 C
66
ꢁ
80 C
85
ꢁ
90 C
98
ꢁ
10
11
12
13
14
15
16
17
100 C
97
ꢁ
110 C
97
ꢁ
120 C
95
ꢁ
90 C
86
ꢁ
90 C
96
ꢁ
15/Fe
15/Fe
15/Fe
3
O
4
4
4
@PC
@car
@PC/car
90 C
82
ꢁ
3
3
O
O
90 C
83
ꢁ
90 C
89
Note: Reaction conditions: dimedone (2 mmol), 4-chlorobenzaldehyde (1 mmol), and required amount of the catalysts.
a
The yields represent the separated product.
that, intermediate 9 will be attained by eliminating one
water molecule from intermediate 8. The subsequent
addition of dimedone to intermediate 9 results in inter-
mediate 10 that converts to intermediate 11 via
tautomerization. Intermediate 11 is followed by dehydra-
tion by removing one water molecule and cyclization to
afford the 1,8-dioxo-octahydroxanthene derivatives 7.
In the following stage, the recoverability of the
SO H@Fe O MNPs was checked in the reaction of
3 | EXPERIMENTAL
All the pure chemical substances were obtained from
Merck, Aldrich, and Fluka chemical companies. Melting
points of the substrate were measured on an
Electrothermal-9100 apparatus and uncorrected. FT-IR
spectra were attained with a PerkinElmer PXI spectrome-
ter in KBr wafers. XRD measurements of the catalyst
were accomplished using a Siemens D-5000 X-ray diffrac-
tometer (Germany) with Cu Kα radiation. Magnetic sus-
ceptibility measurements were carried out by means of
VSM (Lake Shore 7200 at 300 kVsm). TGA was per-
formed under nitrogen by means of a PerkinElmer
instrument. A TEM image was attained using a JEM-
1010 instrument.
3
3 4
4
4
-hydroxycoumarin/indole/dimedone
-chlorobenzaldehyde under the optimum reaction con-
with
ditions (Figure 7). At the end of the reaction, the catalyst
was separated easily by means of a suitable magnet.
Then, water was poured into the reaction solution, and
the resulted sediment was isolated through filtration in
high purity. The recovered SO H@Fe O MNPs were
3
3 4
rinsed several times with chloroform, dried, and reused
with no considerable reduction of its efficiency for a min-
imum of six runs.
3.1 | Catalyst synthesis
To show the merits of this catalytic system in compar-
ison with the same results of the literature, we summa-
rized the outcomes for the production of 3,3 -
3.1.1 | Preparation of Fe O4
3
0
The MNPs were produced according to the reported
2
+
3+
(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-
chemical coprecipitating Fe and Fe ions in the pres-
ence of NaOH solution.
[
88]
methane, and 1,8-dioxo-octahydroxanthene derivatives in
combination with SO H@Fe O MNPs in Table 7. As
Briefly, FeCl ꢀ6H O (5.4 g)
3
2
and FeCl ꢀ4H O (2.0 g) were dissolved in 40 ml of dis-
3
3
4
2
2
shown, this synthetic protocol avoids disadvantages of
the other procedures, such as organic solvents, long reac-
tion times, excess reagents, toxic reagents, and low yield.
tilled water containing concentrated HCl (0.9 ml) in a
three-necked bottle under continuous flow of nitrogen
2
gas. Thereafter, NaOH solution (25 ml) was added to Fe

WU AND XI PENG
13
TABLE 6
3 3 4
Synthesis of 1,8-dioxo-octahydroxanthene derivatives using SO H@Fe O MNPs as a catalyst
ꢁ
ꢁ
M.P (lit) ( C)
Entry
1
RCHO (2)
Product
Time (min)
Yield (%)
M.P(Obsd) ( C)
[
[
[
76]
76]
77]
22
93
202–204
226–228
184–186
203–205
225–227
185–187
2
3
17
17
97
95
[
76]
4
5
10
10
98
96
235–238
253–256
233–235
254–255
[
57]
[
76]
6
7
18
18
94
95
252–255
171–173
251–253
170–171
[
77]
[
78]
8
15
97
225–228
224–226
(
Continues)

14
WU AND XI PENG
TABLE 6 (Continued)
ꢁ
ꢁ
Entry
9
RCHO (2)
Product
Time (min)
Yield (%)
M.P(Obsd) ( C)
M.P (lit) ( C)
[
79]
8
97
240–242
241–243
[
80]
1
0
10
95
223–225
221–223
[
81]
1
1
1
2
20
18
92
91
268–270
244–246
268–271
246–247
[
81]
[
82]
1
3
25
91
225–227
224–226
[
[
[
82]
82]
81]
1
1
1
4
5
6
32
35
20
93
92
90
212–215
255–257
254–257
210–213
257–258
256–258

WU AND XI PENG
15
TABLE 6 (Continued)
ꢁ
ꢁ
M.P (lit) ( C)
Entry
RCHO (2)
Product
Time (min)
Yield (%)
M.P(Obsd) ( C)
[81]
1
7
15
95
225–227
234
ꢁ
Note: Reaction conditions: dimedone (2 mmol), aldehyde (1 mmol), and SO
3
H@Fe
3
O
4
MNPs (15 mg) at 90 C.
+
3+
and Fe
solution at ambient temperature under
and the resulting mixture was refluxed at a temperature
of 80 C for 8 hr, under vigorous agitation and nitrogen
ꢁ
intense mechanical stirring. In the last step, the precipi-
tates were isolated by means of a suitable external mag-
netic field and rinsed several times with deionized water
atmosphere. Subsequently, the resultant ultrafine mag-
netic particles were isolated from the aqueous solution
through decanting by a magnet and rinsed several times
with water and ethanol to remove unreacted organic
groups. Finally, the obtained Fe O @Car was dried in an
ꢁ
and dried under vacuum at 40 C for 24 hr.
3
4
3
.1.2 | Preparation of Fe O @PC
oven overnight.
3
4
In a usual reaction, Fe O (1.0 g) nanoparticles were
3
4
suspended in 50 ml of dry toluene and sonicated for
0 min in an ultrasonic bath under a nitrogen atmo-
sphere. Then, 3-chloropropyltriethoxysilane (CPTCSi)
2 ml) was poured into the reaction solution, and the
3.1.4 | Preparation of Fe O @PC/car
3 4
2
Fe O @PC (1 g) and Fe O @Car (1 g) were poured into
3
4
3 4
(
50 ml of dry ethanol. Then, three drops of Et N were
3
resultant mixture was refluxed and mechanically agitated
for 24 hr. After this period of time, the precipitates of
Fe O @PC were rinsed several times with ethanol and
poured into the reaction mixture, and the obtained mix-
ture was agitated for 12 hr under reflux condition. After
12 hr, Fe O @PC/Car was isolated by a permanent mag-
3
4
3 4
distilled water to eliminate any unreacted chemicals.
Finally, the black product was dried under vacuum oven.
net, rinsed with water, and dried in a vacuum.
3
.1.5 | Preparation of
3
.1.3 | Preparation of Fe O @car
SO H@Fe O MNPs
3 4
3
3 4
Typically, FeCl .6H O (5.8 g) and FeCl .4H O (2.1 g)
To prepare SO H@Fe O MNPs, Fe O @PC/Car (2 g)
3 3 4 3 4
3
2
2
2
were added to 100 ml of distillate water, and l-carnosine
6.3 g) was poured into the reaction solution. The reac-
was suspended in 50 ml of dry dichloromethane, and
chlorosulfonic acid (10 mmol) was added dropwise into
the reaction mixture. The reaction solution was agitated
for 8 hr, and then, the precipitates were separated with a
permanent magnet. The resultant SO H@Fe O MNP
(
tion solution was vigorously stirred at a constant temper-
ꢁ
ature of 40 C for 20 min under nitrogen atmosphere.
Then, NaOH solution was added dropwise into the reac-
tion mixture until the pH of the suspension increased to
ꢂ11. By adding the NaOH solution to this suspension,
the black precipitate of l-carnosine-coated iron oxide
nanoparticles (Fe O @Car) was immediately formed,
3
3 4
material was washed several times with water and etha-
ꢁ
nol, dried at 80 C for 24 hr, and stored in glass vials. All
stages of the SO H@Fe O MNPs synthesis are demon-
3
3 4
strated in Scheme 3.
3
4

16
WU AND XI PENG
SCHEME 2 An acceptable
mechanism for the synthesis of
,8-dioxo-octahydroxanthenes in the
existence of SO H@Fe MNPs
under solvent-free conditions
1
3
3 4
O
0
3 3 4
H@Fe O MNPs in synthesizing 3,3 -(arylmethylene)-bis-(4-hydroxycoumarin) (a), bis-(indolyl)-
FIGURE 7 The recycling of SO
methane (b), and 1,8-dioxo-octahydroxanthene derivatives (c)

WU AND XI PENG
17
0
Comparison of the current method with other reported strategies for synthesizing 3,3 -(arylmethylene)-bis-
TABLE 7
(
4-hydroxycoumarin), bis-(indolyl)-methane, and 1,8-dioxo-octahydroxanthene derivatives
ꢁ
Entry
Catalyst
Catalyst loading
Conditions
Temp ( C)
Time (min)
Yield (%)
References
[
[
[
[
[
83]
65]
67]
26]
68]
1
2
3
4
5
6
TBAB
SDS
10 mol%
20 mol%
10 mol%
A few drop
40 mg
H
H
H
2
2
2
O
O
O
100
60
25
91
98
95
96
95
96
180
28
I
2
100
r. t.
80
Piperidine
RHA-SO
SO H@Fe
EtOH
240
10
3
H
2
H O
3
3
O
4
MNPs
15 mg
Solvent-free
80
10
This work
[
[
[
[
70]
43]
42]
39]
1
2
3
4
5
6
FeCl
ZrOCl
[hmim]HSO
Sulfamic acid
3
-RiH
150 mg
5 mol%
1 mol%
10 mol%
0.1 mmol
10 mg
EtOH
O-EtOH
80
15
180
60
30
16
8
92
93
97
92
80
92
2
.8H
2
O
H
2
r. t.
r. t.
r. t.
90
4
EtOH
Solvent-free
Solvent-free
Solvent-free
+
-/
[40]
(PhCH
2
PPh
3
) Br
3
SiO
2
SO H@Fe
3
3
O
4
MNPs
80
This work
[
[
[
[
[
84]
85]
86]
87]
80]
1
2
3
4
5
6
[Dsim]cl
[Hmim]TFA
[Et NH][HSO
10 mol%
100 mg
1 mmol
100 mg
0.25 mmol
15 mg
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
70
80
100
80
55
90
3
97
82
92
85
93
97
210
30
90
5
3
4
]
[bmim]HSO
DSIMHS
4
SO
3
H@Fe
3
O
4
MNPs
15
This work
3
.1.6 | General procedure for
improvement of the reaction was controlled by TLC ana-
lyses. At the end of the reaction, the catalyst was collected
from the reaction solution by an external magnetic field,
washed with chloroform, dried under decreased pressure,
and reused without considerable decrease in its perfor-
mance for a minimum of six runs. The corresponding
solid product was rinsed by adding boiling water and
purified via its recrystallization from aqueous ethanol.
0
synthesizing 3,3 -(arylmethylene)-bis-
(
(
4-hydroxycoumarin) derivatives
3) catalyzed by SO H@Fe O MNPs
3
3 4
A mixture of 4-hydroxycoumarin (2 mmol), aldehyde
1 mmol) and SO H@Fe O MNPs (15 mg) was heated at
(
3
3 4
ꢁ
a temperature of 80 C under solvent-free conditions. The

18
WU AND XI PENG
3 3 4
SCHEME 3 All stages of the SO H@Fe O MNP synthesis
3
.1.7 | General procedure for
rinsed with chloroform, dried under decreased pressure,
and reused without considerable decrease in its perfor-
mance for a minimum of six runs. The corresponding
solid product was rinsed by adding boiling water and
purified via its recrystallization from aqueous ethanol.
synthesizing bis-(indolyl)-methane
derivatives (5) catalyzed by
SO H@Fe O MNPs
3
3 4
A combination of indole (2 mmol), aldehyde (1 mmol),
and SO H@Fe O MNPs (10 mg) was heated in an oil
3
3
4
ꢁ
bath at 80 C under solvent-free conditions. The devel-
opment of the reaction was checked using TLC ana-
lyses. At the end of the reaction, the catalyst was
collected from the reaction mixture using a permanent
magnet, washed with chloroform, dried under
decreased pressure, and reused with a slight reduction
in its performance for a minimum of six runs. The
corresponding solid product was rinsed with adding
boiling water and purified via recrystallization from
aqueous ethanol.
4 | CONCLUSION
In summary, a new heterogeneous catalyst, SO H@Fe O
3 4
3
MNPs, was prepared and characterized, and its catalytic
behavior was verified. SO H@Fe O MNPs were proven
3
3 4
to be an efficient magnetic nanocatalyst for synthesizing
0
3,3 -(arylmethylene)-bis-(4-hydroxycoumarin),
bis-
(indolyl)-methane, and 1,8-dioxo-octahydroxanthene
derivatives via three one-pot multicomponent reactions
under solvent-free conditions. This procedure provides
some advantages such as short time of reaction, mild
reaction conditions, excellent yields, and easy recovery of
the catalyst by permanent magnetic field. This catalyst
illustrated suitable recyclability without any significant
decrease in catalytic activity after six runs.
3
.1.8 | General procedure for
synthesizing 1,8-dioxo-octahydroxanthene
derivatives (7) catalyzed by
SO H@Fe O MNPs
3
3 4
REFERENCES
A mixture of dimedone (2 mmol), aldehyde (1 mmol),
and SO H@Fe O MNPs (15 mg) was heated at a temper-
ature of 90 C under solvent-free conditions. The improve-
ment of the reaction was controlled by TLC analyses. At
the end of the reaction, the catalyst was collected from
the reaction mixture by a permanent magnetic field,
[
1] Y. Liu, J. Zhang, X. Zhang, B. Li, X. Wang, H. Cao, D. Wei,
Z. Zhou, A. K. Cheetham, J. Mater. Chem. A. 2016, 4(11), 4280.
2] X. Shen, Q. Wang, W. L. Chen, Y. Pang, Appl. Surf. Sci. 2014,
3
3 4
ꢁ
[
317, 1028.
[3] S. Sajjadifar, M. A. Zolfigol, F. Tami, J. Chin. Chem. Soc. 2019,
66, 307. https://doi.org/10.1002/jccs.201800171.

WU AND XI PENG
19
[
4] B. B. F. Mirjalili, Z. Zaghaghi, A. Monfared, J. Chin. Chem.
Soc. 2020, 67, 197. https://doi.org/10.1002/jccs.201900264.
5] S. Bahrami, S. Jamehbozorgi, S. Moradi, S. Ebrahimi, J. Chin.
Chem. Soc. 2020, 67, 603. https://doi.org/10.1002/jccs.
[33] P. Diana, A. Carbone, P. Barraja, A. Martorana, O. Gia,
L. DallaVia, G. Cirrincione, Bioorg. Med. Chem. Lett. 2007, 17
(22), 6134.
[34] S. B. Bharate, J. B. Bharate, S. I. Khan, B. L. Tekwani,
M. R. Jacob, R. Mudududdla, R. R. Yadav, B. Singh,
P. R. Sharma, S. Maity, B. Singh, Eur. J. Med. Chem. 2013,
63, 435.
[35] K. V. Sashidhara, A. Kumar, M. Kumar, A. Srivastava, A. Puri,
Bioorg. Med. Chem. Lett. 2010, 20(22), 6504.
[36] A. Kamal, Y. V. V. Srikanth, M. J. Ramaiah, M. N. Khan,
M. K. Reddy, M. Ashraf, A. Lavanya, S. N. Pushpavalli, Bioorg.
Med. Chem. Lett. 2012, 22(1), 571.
[
2
01900234.
[
6] S. F. Motevalizadeh, M. Khoobi, A. Sadighi, M. Khalilvand-
Sedagheh, M. Pazhouhandeh, A. Ramazani, M. A. Faramarzi,
A. Shafiee, J. Mol, Catal B: Enzym. 2015, 120, 75.
[
[
[
7] Y. Y. Xu, M. Zhou, H. J. Geng, J. J. Hao, Q. Q. Ou, S. D. Qi,
H. L. Chen, X. G. Chen, Appl. Surf. Sci. 2012, 258(8), 3897.
8] A. R. Abbasi, H. Kalantary, M. Yousefi, A. Ramazani,
A. Morsali, Ultrason Sonochem. 2012, 19(4), 853.
9] R. Makiura, S. Motoyama, Y. Umemura, H. Yamanaka,
O. Sakata, H. Kitagawa, Nat. Mater. 2010, 9(7), 565.
[37] A. Hasaninejad, M. Shekouhy, A. Zare, S. M. S. H. Ghattali,
N. Golzar, J. Iran Chem. Soc. 2011, 8(2), 411.
[38] S. Ji, S. Wang, Y. Zhang, T. Loh, Tetrahedron. 2004, 60(9),
2051.
[
[
10] A. Schatz, O. Reiser, W. J. Stark, Chem. Eur. J. 2010, 16(30), 8950.
11] A. H. Lu, E. E. Salabas, F. Schuth, Angew. Chem. Int. Ed. 2007,
4
6(8), 1222.
[39] L. T. An, F. Q. Ding, J. P. Zou, X. H. Lu, L. L. Zhang, Chin.
J. Chem. 2007, 25(6), 822.
[
12] R. Dalpozzo, Green. Chem. 2015, 17(7), 3671.
[
13] F. Panahi, S. K. Dangolani, A. Khalafi-Nezhad, Che-
mistrySelect. 2016, 1(13), 3541.
[40] F. Shirini, M. S. Langroodi, M. Abedini, Chin. Chem. Lett.
2010, 21(11), 1342.
[
[
[
14] D. Wang, D. Astruc, Chem. Rev. 2014, 114(14), 6949.
15] C. C. Berry, A. S. G. Curtis, J. Phys. D. 2003, 36(13), 198.
16] N. Nasongkla, E. Bey, J. Ren, H. Ai, C. Khemtong, J. S. Guthi,
S. F. Chin, A. D. Sherry, D. A. Boothman, J. Gao, Nano. Lett.
[41] S. Y. Wang, S. J. Ji, Tetrahedron. 2006, 62(7), 1527.
[42] D. G. Gu, S. J. Ji, Z. Q. Jiang, M. F. Zhou, T. P. Loh, Synlett.
2005, 2005(6), 959.
[43] S. Mishra, R. Ghosh, Indian. J. Chem., Sect B: Org. Chem. Incl.
Med. Chem. 2011, 50, 1630.
2
006, 6(11), 2427.
[
17] M. Arruebo, R. Fernandez-Pacheco, M. R. Ibarra,
J. Santamaria, Nano. Today. 2007, 2(3), 22.
[44] J. P. Poupelin, G. Saint-Rut, O. Foussard-Blanpin, Eur. J. Med.
Chem. 1978, 13, 67.
[
[
18] J. Dobson, Drug. Dev. Res. 2006, 67(1), 55.
[45] O. Sirkecioglu, N. Talinli, A. Akar, J. Chem. Res. (S) 1995,
8, 502.
[46] J. F. Callan, A. P. De Silva, D. C. Magri, Tetrahedron. 2005, 61
(36), 8551.
[47] S. Hatakeyma, N. Ochi, H. Numata, S. Takano, J. Chem. Soc.,
Chem. Commun. 1988, 54, 1202.
19] M. Lewin, N. Carlesso, C. H. Tung, X. W. Tang, D. Cory,
D. T. Scadden, R. Weissleder, Nat. Biotechnol. 2000, 18(4), 410.
20] J. Govan, Y. K. Gun'ko, Nanomaterials. 2014, 4(2), 222.
21] S. S. Bhattacharyya, S. Paul, S. K. Mandal, A. Banerjee,
N. Boujedaini, A. R. Khuda-Bukhsh, Eur. J. Pharmacol. 2009,
[
[
1
4(1–3), 128.
[48] G. P. Ellis, The chemistry of heterocyclic compounds. in
[
22] J. Neyts, E. D. Clercq, R. Singha, Y. H. Chang, A. R. Das,
S. K. Chakraborty, S. C. Hong, S. C. Tsay, M. Hsu, J. R. Hwu,
J. Med. Chem. 2009, 52(5), 1486.
Chromene, Chromanes and Chromone, Vol.
A. Weissberger, T. ECE), John Wiley, New York, NY
1977, p. 13.
2
(Eds:
[
23] Y. Kong, Y. J. Fu, Y. G. Zu, F. R. Chang, Y. H. Chen, X. L. Lio,
J. Stelten, H. M. Schiebel, Food. Chem. 2010, 121(4), 1150.
24] P. Zhou, Y. Takaishi, H. Duan, B. Chen, G. Honda, M. Itoh,
Y. Takeda, O. K. Kodzhimatov, K. H. Lee, Phytochemistry.
[49] B. Rajitha, B. S. Kumar, Y. T. Reddy, P. N. Reddy,
N. Sreenivasulu, Tetrahedron Lett. 2005, 46(50), 8691.
[50] X. S. Fan, Y. Z. Li, X. Y. Zhan, X. Y. Hu, J. J. Wang, Chin.
Chem. Lett. 2005, 16(7), 897.
[
2
000, 53(6), 689.
[51] E. C. Horning, M. G. Horning, J. Org. Chem. 1946, 11(1), 95.
[52] G. Song, B. Wang, H. Luo, L. Yang, Catal. Commun. 2007, 8
(4), 673.
[53] A. Ilangovan, S. Malayappasamy, S. Muralidharan,
S. Maruthamuthu, Chem. Cent. J. 2011, 5((1)), 81.
[54] B. Das, P. Thirupathi, I. Mahender, V. S. Reddy, Y. K. Rao,
J. Mol. Catal. A: Chem. 2006, 247(1–2), 233.
[
25] C. Ito, M. Itoigawa, S. Onoda, A. Hosokawa, N. Ruangrungsi,
T. Okuda, H. Tokuda, H. Nishino, H. Furukawa, Phytochemis-
try. 2005, 66(5), 567.
26] K. M. Khan, S. Iqbal, M. A. Lodhi, G. M. Maharvi,
M. I. Choudhary, S. Perveen, Bioorg. Med. Chem. 2004, 12(8), 1963.
27] H. Hussain, J. Hussain, A. Al-Harrasi, K. Krohn, Tetrahedron.
[
[
[
[
[
[
[
2
012, 68(12), 2553.
[55] L. Q. Wu, Y. F. Wu, C. G. Yang, L. M. Yang, L. J. Yang,
28] I. Manolov, C. Maichle-Moessmer, N. Danchev, Eur. J. Med.
Chem. 2006, 41(7), 882.
29] M. Abbasi-Tarighat, E. Shahbazi, K. Niknam, Food. Chem.
J. Braz. Chem. Soc. 2010, 21(5), 941.
[56] D. Prasad, A. Preetam, M. Nath, C.R. Chim. 2012, 15(8), 675.
[57] S. Kantevari, R. Bantu, L. Nagarapu, Arkivoc. 2006, 16(6), 136.
[58] X. Fan, X. Hu, X. Zhang, J. Wang, Can. J. Chem. 2005, 83(1), 16.
[59] Z. I. Taka, M. Mohd Kamarulzaki, A. S. Khairunnadim,
A. Saliza, IJNeaM. 2019, 12(4), 401.
[60] F. Ge, M. M. Li, H. Ye, B. X. Zhao, J. Hazard. Mater. 2012,
211, 366.
[61] V. Alagarsamy, G. Murugananthan, R. Venkateshperumal,
Biol. Pharm. Bull. 2003, 26(12), 1711.
2
013, 138(2–3), 991.
30] W. Wang, S. X. Wang, X. Y. Qin, J. T. Li, Synth. Commun.
005, 35(9), 1263.
2
31] K. Niknam, D. Saberi, M. Sadegheyan, A. Deris, Tetrahedron
Lett. 2010, 51(4), 692.
32] H. Zang, Q. Su, Y. Mo, B. Cheng, Ultrason. Sonochem. 2011, 18
(1), 68.

20
WU AND XI PENG
[
[
[
62] M. J. Hour, L. J. Huang, S. C. Kuo, Y. Xia, K. Bastow,
[78] A. Khazaei, A. R. Moosavi-Zare, Z. Mohammadi, A. Zare,
V. Khakyzadeh, G. Darvishi, RSC Adv. 2013, 3(5), 1323.
[79] A. Hasaninejad, M. Dadar, A. Zare, Chem. Sci. Trans. 2012, 1
(2), 233.
[80] F. Shirini, A. Yahyazadeh, K. Mohammadi, Chin. Chem. Lett.
2014, 25(2), 341.
[81] A. Amoozadeh, S. Rahmani, J. Mol. Catal. A. Chem. 2014,
396, 96.
[82] H. R. Shaterian, A. Hosseinian, M. Ghashang, Turk. J. Chem.
2009, 33(2), 233.
[83] J. M. Khurana, S. Kumar, Tetrahedron Lett. 2009, 50(28), 4125.
[84] M. A. Zolfigol, V. Khakyzadeh, A. R. Moosavi-Zare, A. Zare,
B. Azimi, Z. Asgari, A. Hasaninejad, C. R. Chim. 2012, 15
(8), 719.
[85] M. Dabiri, M. Baghbanzadeh, E. Arzroomchilar, Catal.
Commun. 2008, 9(5), 939.
[86] Z. Zhou, X. Deng, J. Mol. Catal. A: Chem. 2013, 367, 99.
[87] K. Niknam, M. Damya, J. Chin. Chem. Soc. 2009, 56(3), 659.
[88] H. Hassani, M. A. Nasseri, B. Zakerinasab, F. Rafiee, Appl.
Organomet. Chem. 2016, 30(6), 408.
Y. Nakanishi, E. Hamel, K. H. Lee, J. Med. Chem. 2000, 43(23),
4
479.
63] V. Alagarsamy, R. Revathi, S. Meena, K. V. Ramaseshu,
S. Rajasekaran, E. De Clercq, Indian J. Pharm. Sci. 2004, 66
(4), 459.
64] R. G. Puligoundla, S. Karnakanti, R. Bantu, N. Kommu,
S. B. Kondra, L. Nagarapu, Tetrahedron Lett. 2013, 54(20), 2480.
65] H. Mehrabi, H. Abusaidi, J. Iran. Chem. Soc. 2010, 7(4), 890.
66] N. Tavakoli-Hoseini, M. M. Heravi, F. F. Bamoharram,
A. Davoodnia, M. Ghassemzadeh, J. Mol. Liq. 2011, 163(3), 122.
67] M. Kidwai, V. Bansal, P. Mothsra, S. Saxena, R. K. Somvanshi,
S. Dey, T. P. Singh, J. Mol. Catal. A: Chem. 2007, 268(1–2), 76.
68] M. Seddighi, F. Shirini, M. Mamaghani, RSC Adv. 2013, 3(46),
[
[
[
[
[
[
[
[
[
2
4046.
69] K. Tabatabaeian, H. Heidari, A. Khorshidi, M. Mamaghani,
N. O. Mahmoodi, J. Serb. Chem. Soc. 2012, 77, 407.
70] F. Shirini, S. Akbari-Dadamahaleh, A. Mohammad-Khah,
C. R. Chim. 2013, 16(10), 945.
71] M. Rekha, H. R. Manjunath, N. Nagaraju, J. Ind. Eng. Chem.
2
013, 19(1), 337.
72] R. Tayebee, M. M. Amini, F. Nehzat, O. Sadeghi,
M. Armaghan, J. Mol. Catal. A: Chem. 2013, 366, 140.
73] R. R. Nagawade, D. B. Shinde, Acta. Chim. Slov. 2006, 53
How to cite this article: Wu X, Peng W-X.
(2), 210.
Heterogeneous SO H@Fe O magnetic
3
3 4
[
[
74] S. Khaksar, S. M. Talesh, J. Fluorine. Chem. 2012, 135, 87.
75] K. Tabatabaeian, N. O. Mahmoodi, M. Ghoraninia,
A. Khorshidi, Orient. J. Chem. 2008, 24(1), 101.
nanocatalyst as an efficient and reusable medium
for the synthesis of 3,3 -(arylmethylene)-bis-(4-
0
hydroxycoumarin), bis-(indolyl)-methane, and 1,8-
dioxo-octahydroxanthene derivatives. J Chin Chem
Soc. 2020;1–20. https://doi.org/10.1002/jccs.
[
76] B. Maleki, M. Gholizadeh, Z. Sepehr, Bull. Korean Chem. Soc.
2
011, 32(5), 1697.
[
77] F. Shirini, G. H. Imanzadeh, M. Abedini, M. Akberi-
Dokhteghaziani, P. Ghods-Ghasemabadi, M. Safarpoor
Langroodi, Iran. J. Catal. 2012, 2(3), 115.
202000087