Synthesis and characterization of VO–vanillin complex immobilized on MCM-41 and its facile catalytic application in the sulfoxidation reaction, and synthesis of 2,3-dihydroquinazolin-4(1H)-ones and disulfides in green media

Article abstract of DOI:10.1002/jccs.201900531

In this work, a vanillin complex is immobilized onto MCM-41 and characterized by FT-IR, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, and BET techniques. This supported Schiff base complex was found to be an efficient and recoverable catalyst for the chemoselective oxidation of sulfides into sulfoxides and thiols into their corresponding disulfides (using hydrogen peroxide as a green oxidant) and also a suitable catalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives in water at 90°C. Using this protocol, we show that a variety of disulfides, sulfoxides, and 2,3-dihydroquinazolin-4(1H)-one derivatives can be synthesized in green conditions. The catalyst can be recovered and recycled for further reactions without appreciable loss of catalytic performance.

Full text of DOI:10.1002/jccs.201900531

Received: 8 December 2019
DOI: 10.1002/jccs.201900531
Revised: 20 February 2020
Accepted: 24 February 2020
A R T I C L E
Synthesis and characterization of VO–vanillin complex
immobilized on MCM-41 and its facile catalytic application
in the sulfoxidation reaction, and synthesis of
2,3-dihydroquinazolin-4(1H)-ones and disulfides in green
media
Mohsen Nikoorazm
| Maryam Khanmoradi
Department of Chemistry, Faculty of
Science, Ilam University, Ilam, Iran
Abstract
In this work, a vanillin complex is immobilized onto MCM-41 and characterized
by FT-IR, X-ray diffraction, scanning electron microscopy, energy dispersive spec-
troscopy, thermogravimetric analysis, and BET techniques. This supported Schiff
base complex was found to be an efficient and recoverable catalyst for the
chemoselective oxidation of sulfides into sulfoxides and thiols into their
corresponding disulfides (using hydrogen peroxide as a green oxidant) and also a
suitable catalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one deriva-
tives in water at 90ꢀC. Using this protocol, we show that a variety of disulfides,
sulfoxides, and 2,3-dihydroquinazolin-4(1H)-one derivatives can be synthesized in
green conditions. The catalyst can be recovered and recycled for further reactions
without appreciable loss of catalytic performance.
Correspondence
Mohsen Nikoorazm, Department of
Chemistry, Faculty of Science, Ilam
University, P. O. Box 69315516, Ilam,
Iran.
Email: e_nikoorazm@yahoo.com
K E Y W O R D S
2, 3-dihydroquinazolin-4(1H)-one, disulfides, hydrogen peroxide, MCM-41 mesoporous, Schiff
base complex, sulfoxides
1 | INTRODUCTION
of many proteins through the formation of covalent bonds
between two different polypeptides or as a part of a
polypeptide[12–14]; in the petroleum industry they assist in
the removal of thiols by converting thiols to disulfides;
and they are also used in the vulcanization of rubber and
elastomers.[15–17] Furthermore, quinazoline frameworks
are an important class of heterocyclic compounds that
have been found to play valuable roles in both the phar-
maceutical industry and academic research.[18] Various
quinazolin-2,4-diones, quinazolin-4-ones, and their deriva-
tives are well known to possess an array of physiological
activities.[19] Particularly, 2,3-dihydroquinazolin-4(1H)-
The selective oxidation of sulfides to chiral/achiral sulfox-
ides is a useful synthetic process in organic chemistry,[1–4]
in which metal-mediated oxidative systems and halogen
derivatives are usually used.[5] Also, they are beneficial
synthetic intermediates for the construction of various
chemically and biologically crucial molecules, particularly
drugs.[6] The selective oxidation of thiols to the
corresponding disulfides, because of the various important
aspects of disulfide bonds, has gained significance in bio-
logical processes and the chemical industry[7,8]
:
For instance, in organic synthesis they act as an
intermediate[9–11]; in biology they occur in the structures
ones may display
a
wide range of medicinal
properties involving antiviral,[20] antihyperlipidemic,[21]
© 2020 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J Chin Chem Soc. 2020;1–13.
http://www.jccs.wiley-vch.de
1

2
NIKOORAZM AND KHANMORADI
antimicrobial,[22]
anti-Parkinsonian,[23]
anti-infla-
added and stirred continuously for 30 min. Then, 5 ml
of TEOS was slowly added under vigorous stirring at
80ꢀC, and the resultant solution was refluxed for 2 hr.
After completion of the reaction, the heating was
stopped and the suspension was cooled down to room
temperature and washed with deionized water. The sur-
factant template was removed by calcination at 550ꢀC
for 5 hr at a heating ramp 2ꢀC/min. Finally, two-
dimensional hexagonal (p6mm) mesoporous MCM-41
was obtained. The catalyst preparation was followed by
the functionalization of MCM-41. For this propose, a
mmatory,[24] antihypertensive,[25] and bronchodilator[26]
activities.
Vanadium compounds have attracted much attention
because they are widely used for heterogeneous organic
transformations. We have directed our research on the
immobilization of oxo-vanadium on the nanoporous
MCM-41. The catalyst has been directly anchored onto
hexagonal mesoporous silica (MCM-41) by the reaction
between the complex and the silanol groups on the sur-
face of MCM-41 through homogeneous and biological
oxidation processes using oxidizing agents such as H2O2
mixture of 4.8
g
of MCM-41 and 4.8
g
of
[27]
and O2.
Different kinds of inorganic supports have
3-aminopropyltriethoxysilane (nPrNH2) was refluxed in
n-hexane under nitrogen atmosphere for 24 hr. After the
reaction time, the resulting white solid of the
functionalized MCM-41
obtained, which was filtered, washed with n-hexane,
been reported for oxo-vanadium catalysis such as USY
zeolites,[28] silica gel,[29] mesoporous silica,[30] and alu-
mina[31] in the search for catalysts using one of two possi-
ble mechanisms: (a) the formation of hydrogen bond
between silanol protons of the support or the pseudo-
π-system of the acetylacetonate ligand, or (b) ligand
exchange with the formation of a covalent bond between
the vanadium center and an oxygen atom from the
MCM-41 heterogeneous support.[32,33] Also, among the
different heterogeneous supports, nanosized silica mate-
rials such as MCM-41 provide excellent intrinsic proper-
ties such as hydrothermal stability, well-defined porosity,
high BET surface area, a wide range of pore dimensions,
and the ability to stabilize metal ions in mesoporous sil-
ica framework, which have made them interesting in het-
erogeneous catalysis.[34] The purpose of this work was to
introduce VO–vanillin-MCM-41 as an environmentally
benign, cheap, highly selective, and heterogeneous cata-
lyst. The presence of this catalyst in the preparation of
sulfoxides, disulfides, and 2,3-dihydroquinazolin-4(1H)-
ones leads to excellent conversion and selectivity.
(nPrNH2-MCM-41) was
and dried overnight under vacuum.
2.3 | Synthesis of Schiff-base-
functionalized MCM-41 mesoporous
material (vanillin–MCM-41)
In a round-bottom flask, 0.5 g of nPrNH2-MCM-41 was
dissolved in absolute ethanol (25 ml). Then 4-hydroxy-
3-methoxybenzaldehyde (vanillin) (1.2 mmol, 0.182 g)
was added to the solution and refluxed under nitrogen
atmosphere for 3 hr. The resultant vanillin-MCM-41 was
filtered, rinsed with ethanol, and dried under vacuum.
2.4 | Synthesis of heterogeneous catalyst
(VO–vanillin-MCM-41)
The heterogeneous catalyst was synthesized by adding
VO (acac)2 (0.63 mmol, 0.168 g) to vanillin-MCM-41
(0.25 g) in ethanol (20 ml) and refluxed for 20 hr. After
the reaction time, the resulting solid impregnated with
the metal complex was collected by filtration and washed
with ethanol. This product is designated as VO–vanillin-
MCM-41 (Scheme 1).
2 | EXPERIMENTAL
2.1 | Materials
The tetraethylorthosilicate (TEOS, 98%), the cationic sur-
factant cetyltrimethylammonium bromide (CTAB, 98%),
solvents, and the other chemicals were supplied by
Merck, Aldrich, or Fluka and were used as received with-
out further purification.
2.5 | General procedure for the synthesis
of sulfoxides
2.2 | Synthesis of (3-aminopropyl)
triethoxysilane–MCM-41
VO–vanillin-MCM-41 (4 mg) was added to a mixture of
the sulfide (1 mmol) and H2O2 (5 mmol) under solvent-
free conditions. The reaction was stirred at room tempera-
ture for the various reaction times, as indicated in Table 3.
After completion of the reaction, which was monitored by
TLC using n-hexane/ acetone (8:2) as the eluent, the
In a typical synthesis, to a solution of NaOH (2 M) in
deionized water (480 ml), 1 g of CTAB, as a quaternary
ammonium compound which is not sensitive to pH, was

NIKOORAZM AND KHANMORADI
3
SCHEME 1 General procedure for
the preparation of VO–vanillin-MCM-41
catalyst
EtO
EtO Si
EtO
O
O Si
O
NH2
OH
OH
OH
NH2
n-hexane, 24 h, reflux
N2 atmospher
MCM-41
nPrNH2-MCM-41
CHO
OH
OCH3
O
O Si
O
N
OH
OH
OCH3
O
O Si
O
N
EtOH, 3 h, reflux
N2 atmospher
OCH3
Vanillin-MCM-41
O
O
O
O Si
O
N
2+
OH
VO
Me
Me
2
O
CH3
CH3
O
N
V
O
OH
O
Ethanol, 20 h reflux
O Si
O
VO-Vanillin-MCM-41
catalyst was removed by centrifugation and the products
were extracted with dichloromethane (3 × 10 ml).
2 ml water was stirred at 90ꢀC for an appropriate time.
After completion of the reaction (determined by TLC), the
precipitate was removed by filtration and subsequently
washed with ethanol. For obtaining the pure product, the
resulting products were recrystallized from ethanol.
2.6 | General procedure for the synthesis
of disulfides
A mixture of thiol (1 mmol), H2O2 (5 mmol), and VO–vanil-
lin-MCM-41 (4 mg) in ethanol was stirred at room tempera-
ture and the progress of the reaction was monitored by TLC.
After completion of the reaction, the catalyst was removed
by simple filtration and washed with dichloromethane. The
product was extracted with CH2Cl2. The organic layers were
separated and dried over anhydrous Na2SO4.
3 | RESULTS AND DISCUSSION
The catalyst sample was characterized by a series of tech-
niques including X-ray diffraction (XRD), inductively
coupled plasma optical emission spectroscopy (ICP-OES),
scanning electron microscopy (SEM), FT-IR, energy dis-
persive spectroscopy (EDS), BET analysis, and ther-
mogravimetric analysis (TGA).
2.7 | General procedure for the synthesis
of 2, 3- dihydroquinazolin-4(1H)-ones
3.1 | Catalyst characterization
A mixture of 2-aminobenzamide (1 mmol), aldehyde
Figure 1 shows the low-angle powder XRD patterns of
(1 mmol), and 20 mg VO–vanillin-MCM-41 as a catalyst in
VO–vanillin-MCM-41. These patterns, when compared

4
NIKOORAZM AND KHANMORADI
FIGURE 1 Small-angle XRD
patterns of VO–vanillin-MCM-41
FIGURE 2 FT-IR spectra of
(a) MCM-41, (b) nPrNH2–MCM-41,
(c) vanillin-MCM-41, and (d) VO–
vanillin-MCM-41
with those reported for MCM-41, can provide conclusive
evidence about the quality of the synthesized material.
As reported in numerous papers, MCM-41's three-peak
pattern was observed with a very strong d100 reflection
and two other weaker reflections for d110 and d200, which
provide the evidence of the hexagonal symmetry of
MCM-41 mesostructure. Here, in the XRD pattern of
VO–vanillin-MCM-41 sample, we found a decrease in the

NIKOORAZM AND KHANMORADI
5
FIGURE 5 TGA thermograms of VO–vanillin-MCM-41
FIGURE 3 SEM images of (a) MCM-41 and (b) VO–vanillin-
MCM-41
FIGURE 6 BET curves of VO–vanillin-MCM-41
vibration, indicating the successful functionalization of
MCM-41 with 3-aminopropyltriethoxysilane (Figure 2b).
The formation of the Schiff base ligand is confirmed by the
presence of the bands at 1651 cm−1, which is assigned to
C N bond, and 1520 cm−1, which is assigned to C C bond
of 4-hydroxy-3-methoxybenzaldehyde (vanillin) (Figure 2c).
Figure 2d shows that the peak due to the stretching vibra-
tion of C N bond in the Schiff base ligand (1651 cm−1) is
shifted to 1638 cm−1 in the VO–vanillin-MCM-41 complex.
The obtained results suggest the successful coordination of
the metal to the vanillin Schiff base.
SEM study was carried out in order to determine the
morphology of the VO–vanillin-MCM-41 catalyst
(Figure 3). The SEM image reveals that the particles are
completely spherical in shape with a uniform size and
there are no other phases or impurities. Also, EDS analy-
sis was performed on VO–vanillin-MCM-41, which is
illustrated in Figure 4. The EDS spectrum indicates the
FIGURE 4 The EDS spectrum of VO–vanillin–MCM-41
2θ value, which is indicative of the fact that MCM-41's
surface silanol groups were functionalized by the VO
Schiff base complex.[35]
Figure 2 presents the FT-IR spectrum of MCM-41,
nPrNH2-MCM-41, vanillin-MCM-41, and VO–vanillin-
MCM-41. In Figure 2a, the characteristic peaks at 1223,
1059, and 790 cm−1 are related to Si O Si bond stretching
vibration, and the peak at 454 cm−1 corresponds to
Si O Si bond bending vibration. In the spectrum of
nPrNH2-MCM-41, the presence of the peak around
1550 cm−1 is mainly due to the NH2 symmetric bending

6
NIKOORAZM AND KHANMORADI
TABLE 1 Textural parameters deduced from nitrogen sorption isotherms
Sample
SBET (m2 g−1
)
Pore dia. (nm)
Pore vol. (cm3/g)
Wall dia. (nm)
VO–vanillin-MCM-41
269.73
1.21
0.6717
1.91
TABLE 2 Optimization conditions for the oxidation of methyl phenyl sulfide in 25 min at room temperature
Entry
Amount of catalyst (mg)
Amount of H2O2 (mmol)
Solvent
Time (min)
Yield (%)a
1
None
5
5
5
5
5
5
4
6
5
5
5
5
Solvent-free
Solvent-free
Dichloromethane
Ethanol
6 hr
25
25
25
25
25
25
25
25
25
25
25
Trace
98
2
8
8
8
8
8
8
8
6
5
4
3
3
40
4
92
5
Acetonitrile
Ethyl acetate
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
80
6
65
7
83
8
70
9
98
10
11
12
98
98
89
aIsolated yields.
existence of O, N, Si, and V elements in the VO–vanillin-
MCM-41 sample. Also, the vanadium content in the VO–
vanillin complex was determined by ICP-OES. Based on
this analysis, the vanadium content in VO–vanillin-
MCM-41 was 0.171 mmol/g.
SCHEME 2 Oxidation of sulfide to sulfoxide in the presence
of VO–vanillin-MCM-41
TGA curve of VO–vanillin-MCM-41 sample is shown in
Figure 5. As reported in previous works, the TGA of MCM-
41 shows a one-step weight loss, which can be assigned to
the desorption of water from the surface of MCM-41.[36]
The TGA curve of VO–vanillin-MCM-41 exhibits three evi-
dent weight losses, which are in the range 100–200ꢀC,
200–300ꢀC, and 340–500ꢀC, corresponding to the loss of
adsorbed water, the decomposition of organic functional
groups, and the decomposition of the silanol groups, respec-
tively. The total mass loss of the VO–vanillin-MCM-41 com-
plex was approximately 24%.
(0.6717 cm3/g) was observed for VO–vanillin-MCM-41
compared to MCM-41. This is due to the increased mate-
rial anchored onto the surface of the MCM-41 support.
The wall thicknesses of MCM-41 and VO–vanillin-MCM-
41 were calculated by the following equation:
2d100
pffiffi
Wall thickness :
−DBJH
3
The nitrogen adsorption–desorption isotherms for
VO–vanillin-MCM-41 (Figure 6) suggest that the prepared
samples have a regular mesoporous framework structure.
For MCM-41, a sharp inflection at ~0.3 relative pressure
(P/P0) suggests a narrow pore size distribution.[36] In the
isotherms of mesoporous materials loaded with VO
(acac)2, the condensation step is shifted to lower P/P0
values, while the total amount of N2 adsorbed decreases.
Nitrogen adsorption–desorption analysis of MCM-41
reported in our previous works shows a surface area of
1372 m2/g and a pore volume of 1.521 cm3/g. A decrease
in the surface area (269.73 m2/g) and pore volume
4 | RESULTS AND DISCUSSION
4.1 | Catalytic studies
In continuation of our previous work,[36–38] we here
report the catalytic activity of VO–vanillin-MCM-41 in
the oxidation of sulfides to sulfoxides and in the synthe-
ses of 2,3-dihydroquinazolin-4(1H)-ones and disulfides in
green media as an efficient, reusable, and nontoxic het-
erogeneous catalyst (Table 1).

NIKOORAZM AND KHANMORADI
7
TABLE 3 Oxidation of various
sulfides to sulfoxidesa
Entry
Product
Time (min)
Yield (%)b
M.p. (ꢀC) [ref.]
1
25
98
30–32 [39]
2
3
5
95
97
Oil [39]
45
121–123 [39]
4
5
900
10
96
93
65–67 [40]
Oil [39]
6
7
40
40
92
98
Oil [39]
Oil [40]
8
9
60
70
95
96
Oil [41]
Liquid [42]
aReaction conditions: substrate (1 mmol), H2O2 (5 mmol), and catalyst (4 mg) at room temperature.
bIsolated yield.
4.1.1 | Oxidation of sulfides into
sulfoxides
In order to evaluate the catalytic selectivity and reactivity
of the system, methyl phenyl sulfide (1 mmol) was
SCHEME 3 Oxidative coupling of thiols to disulfides
catalyzed by VO–vanillin-MCM-41

8
NIKOORAZM AND KHANMORADI
TABLE 4 Effect of different solvents, amount of catalyst, and oxidant on the oxidative coupling of thiophenol to diphenyl disulfide
Entry
Amount of catalyst (mg)
Amount of oxidant (mmol)
Solvent
Time (min)
Yield (%)a
1
None
5
5
5
5
4
7
5
5
5
5
Ethanol
5 hr
25
25
25
25
25
25
25
25
25
Trace
90
2
3
4
5
4
4
4
4
4
4
Ethanol
3
Ethanol
95
4
Ethanol
95
5
Ethanol
83
6
Ethanol
65
7
Dichloromethane
Acetonitrile
Ethyl acetate
n-Hexane
89
8
90
9
91
10
92
aIsolated yield.
selected as the model substrate for the optimization of
the reaction conditions and for studying the influence of
various parameters such as the amount of catalyst, nature
of the solvents, and concentration of hydrogen peroxide
as oxidant.
primary hydroxyl groups in these substrates remained
intact during the oxidation reactions (Table 3, entries
5 and 6). The results are summarized in Table 3.
To show the catalytic role of VO–vanillin-MCM-41,
the model reaction was carried out in the absence of the
catalyst at room temperature (Table 2, entry 1). It was
observed that the reaction was not completed even after
6 hr. This shows that the presence of the described cata-
lyst is necessary for this transformation. The use of 4 mg
catalyst afforded the desired product in acceptable yield
(98%). We next focused on the effect of the solvents dic-
hloromethane, ethanol, acetonitrile, and ethyl acetate
(Table 2, entries 2–6). It was observed that progress of
the reaction was not satisfactory with the above sol-
vents. We further conducted the same reaction under
solvent-free conditions, and found that the reaction
proceeded more efficiently under such condition
(Table 2, entry 2).
Performing the oxidation of methyl phenyl sulfide
with various molar ratios of H2O2 showed that the
amount of oxidant considerably affects the yield of the
product. As the result show, the desired product was not
obtained when less than 5 mmol of H2O2 was used as oxi-
dant; when a larger concentration (7 mmol) was used,
the conversion to sulfoxide decreased and sulfone began
to form (Table 2, entries 7–8) (Scheme 2).
4.1.2 | Oxidative coupling of thiols into
disulfides
In order to explore the selectivity and activity of the VO–
vanillin-MCM-41 complex better, oxidative coupling of
thiols was investigated using this catalyst in the presence
of hydrogen peroxide. Optimization experiments for the
oxidative coupling of thiols were initially performed
using thiophenol (1 mmol) as the model substrate under
different conditions (Scheme 3).
In our investigation, we found that the reaction gave
no discernable conversion in the absence of the catalyst
even after 5 hr (Table 4, entry 1). The catalyst amount
was varied from 3 to 5 mg while keeping all other param-
eters the same (Table 4, entries 2–4), and the optimum
value of the catalyst was found to be 4 mg. Finally, we
carried out the oxidation reaction with different amounts
of H2O2 as green oxidant. The best result was obtained in
the presence of 5 mmol of hydrogen peroxide and pro-
duced the disulfide only. Besides, after screening various
solvents (Table 4, entries 3, 7–10), It was found that the
reaction proceeded efficiently in both nonpolar solvents
such as n-hexane and polar solvents such as acetonitrile
and ethanol with good conversion and selectivity. Based
on these results, ethanol was concluded to be an ideal
medium for this reaction.
Based on these optimization studies, a wide range of
sulfides with various functional groups were converted to
their corresponding sulfoxides at room temperature
under solvent-free condition using 5 mmol H2O2 in the
presence of 4 mg of catalyst (Table 3). Interestingly, when
2-(phenylthio)ethanol and 2-(methylthio)ethanol deriva-
tives were used as substrates, it was observed that the
To extend the scope of this method, other organo-
thiols with different functional groups were subjected to
the oxidative coupling reaction. As shown in Table 5,
aromatic thiols having the methyl group, such as

NIKOORAZM AND KHANMORADI
9
TABLE 5 Selective oxidative coupling of thiols to disulfidesa
Entry
Product
Time (min)
Yield (%)b
M.p. (ꢀC) [ref.]
1
55
95
65–66 [43]
2
15
97
40–42 [44]
3
4
30
50
90
90
86–88 [45]
175–176 [45]
5
6
25
60
95
91
56–57 [44]
278–280 [43]
7
8
50
45
95
94
53–55 [44]
91–92 [43]
9
100
70
88
90
Oil [46]
Oil [43]
10
aReaction conditions: substrate (1 mmol), H2O2 (5 mmol), and catalyst (4 mg) in ethanol at room temperature.
bIsolated yield.
4-methyl thiophen, showed a higher yield and needed a
shorter reaction time (Table 5, entry 2) than thiophenol
(Table 5, entry 1). This is likely due to the electron-
donating ability of the methyl group. Thiols with the
carboxylic acid groups took a longer reaction time
(Table 5, entries 6, 9). It is also obvious that aromatic
thiols react faster than aliphatic thiols and that for
SCHEME 4 Synthesis of 2,3-dihydroquinazolin-4(1H)-ones
catalyzed by VO–vanillin-MCM-41

10
NIKOORAZM AND KHANMORADI
TABLE 6 Optimization of the conditions for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones via the condensation of
4-chlorobenzaldehyde (1 mmol) and 2-aminobenzamide (1 mmol)
Entry
Catalyst (mg, mol%)
Temperature (ꢀC)
Solvent
H2O
Time (min)
8 hr
120
Yield (%)a
1
None
4
80
80
80
80
80
80
80
90
70
80
90
Trace
30
2
H2O
3
8
H2O
120
40
4
10
15
20
25
20
20
20
20
H2O
120
55
5
H2O
120
75
6
H2O
120
88
7
H2O
120
88
8
H2O
120
93
9
H2O
120
76
10
11
EtOH (reflux)
PEG
120
90
120
88
aIsolated yield.
TABLE 7 Synthesis of 2, 3-dihydroquinazolin-4(1H)-ones catalyzed by VO–vanillin-MCM-41 in water at 90ꢀCa
Entry
Product
Time (min)
Yield (%)b
M.p. (ꢀC) [ref.]
1
130
96
220–223 [47]
2
3
4
140
130
135
94
95
93
191–193 [47]
166–168 [47]
229–231 [47]
5
6
70
80
92
95
190–193 [47]
195–198 [47]
(Continues)

NIKOORAZM AND KHANMORADI
11
TABLE 7 (Continued)
Entry
Product
Time (min)
Yield (%)b
M.p. (ꢀC) [ref.]
7
120
93
202–205 [47]
8
145
70
91
90
93
196–199 [47]
274–278 [47]
156–158 [48]
9
10
70
11
60
95
161–165 [45]
aReaction conditions: substrate (1 mmol), 2-aminobenzamide (1 mmol), and catalyst (20 mg) in water at 90ꢀC.
bIsolated yield.
aromatic thiols the conversion time is shorter (Table 5,
entries 9, 10).
4.2 | Synthesis of 2,3-dihydroquinazolin-
4(1H)-one derivatives
For the preparation of 2, 3-dihydroquinazolin-4(1H)-
ones, the reaction between 4-chlorobenzaldehyde
(1 mmol) and 2-aminobenzamide (1 mmol) was selected
as the model reaction (Scheme 4).
Initially, the model reaction was performed in the
absence of VO–vanillin-MCM-41 in water at 80ꢀC for
8 hr (Table 6, entry 1). Only trace amount of the product
was obtained after prolonged reaction time. Then various
amount of the catalyst (4, 8, 10, 15, 20, and 25 mg) were
used (Table 6, entries 2–7). It was observed that by
increasing the amount of the catalyst, the product yield
also increased. However, >20 mg of the catalyst did not
make any difference in the yield (Table 6, entry 7). On
FIGURE 7 Reusability of VO–vanillin-MCM-41 catalyst for
the preparation of sulfoxide (column a), disulfide (column b), and
2,3-dihydroquinazolin-4(1H)-one (column c)

12
NIKOORAZM AND KHANMORADI
the other hand, the use of a higher temperature improved
the yield (Table 6, entry 8). To consider the solvent effect
on the model reaction, several solvents were tested
(Table 6, entries 10, 11), and water was selected as the
optimal solvent in terms of activity and selectivity
(Table 6, entry 8). Water as an attractive solvent has high
dielectric constant, high cohesive energy density, and
high internal pressure, and it is nontoxic, nonflammable,
and inexpensive. Consequently, 20 mg of catalyst, water
as solvent, and 90ꢀC as the suitable temperature were
selected as the best condition for the reaction (Table 6).
To examine the generality of the green procedure for
the synthesis of 2,3-dihydroquinazolin-4. (1H)-ones, we
carried out the reactions of 2-aminobenzamideand with
other aromatic and aliphatic aldehydes under similar
optimized reaction conditions, as given in Table 7.
The reusability of the catalyst was investigated under
the optimum reaction conditions for (a) the oxidation of
methyl phenyl sulfide, (b) the oxidative coupling of
thiophenol and (c) the synthesis of 2-(4-chlorophenyl)-2,-
3-dihydoquinazolin-4(1H)-one. After the completion of
the reaction, the catalyst was separated via centrifuga-
tion. Then, it was dried and reused for subsequent experi-
ments. The reaction was performed six times over VO–
vanillin-MCM-41 as the heterogeneous catalyst without
any detectable change in its activity (Figure 7).
in all described reactions, with similar catalytic activity
and selectivity as the original one.
ORCID
Mohsen Nikoorazm https://orcid.org/0000-0002-4013-
0868
REFERENCES
[1] E. Zamanifar, F. Farzaneh, J. Simpson, M. Maghami, Inorg.
Chim. Acta 2014, 414, 63.
[2] M. Nikoorazm, A. Ghorbani-Choghamarani, M. Khanmoradi,
Appl. Organomet. Chem. 2016, 30, 236.
[3] M. Khanmoradi, M. Nikoorazm, A. Ghorbani-Choghamarani,
Appl. Organomet. Chem. 2017, 31, 3693.
[4] F. Gregori, I. Nobili, F. Bigi, R. Maggia, G. Predieri, G. Sartori,
J. Mol. Catal. A Chem. 2008, 286, 124.
[5] Z. G. Xiong, J. Zhang, X. M. Hu, Appl. Catal. A. Gen. 2008,
334, 44.
[6] A. Ghorbani-choghamarani, S. Sardari, Chin. J. Catal. 2010,
31, 1347.
[7] X. Lang, J. Zhao, X. Chen, Angew. Chem. Int. Ed. 2016, 55,
4697.
[8] Q. Pu, M. Kazemi, M. Mohammadi, Mini. Rev. Org. Chem.
2019, 16, 5775.
[9] L. Chen, A. Noory Fajer, Z. Yessimbekov, M. Kazemi,
M. Mohammadi, J. Sulfur Chem. 2019, 40, 451.
[10] A. R. Hajipour, S. E. Mallakpour, H. J. Adibi, Org. Chem. 2002,
67, 8666.
Also, to test whether the metal was leaching out from
the solid catalyst during the reaction, ICP analysis was
performed on the recovered catalyst. Based on this analy-
sis, the vanadium content in the recovered VO–vanillin-
MCM-41 catalyst was 0.166 mmol/g. That is, compared to
the fresh catalyst, the recycled catalyst was truly
heterogeneous.
[11] M. Kirihara, Y. Asai, S. Ogawa, T. Noguchi, A. Hatano,
Y. Hirai, Synthesis 2007, 21, 3286.
[12] S. G. Kim, D. K. Park, W. J. Suck, J. S. Lee, S. K. Seong,
M. H. Chung, Bull. Environ. Contam. Toxicol. 2008, 81, 470.
[13] A. Saxena, A. Kumar, S. Mozumdar, J. Mol. Catal. A Chem.
2007, 269, 35.
[14] C. C. Silveira, S. R. Mendes, Tetrahedron Lett. 2007, 48, 7469.
[15] S. Ghammamy, M. Tajbakhsh, J. Sulfur Chem. 2005, 26, 145.
[16] L. Menini, M. C. Pereira, A. C. Ferreira, J. D. Fabris,
E. V. Gusevskaya, Appl. Catal. A. Gen. 2011, 392, 151.
[17] D. Jiang, G. Pan, B. Zhao, G. Ran, Y. Xie, E. Min, Appl. Catal.
A. Gen. 2000, 2011, 69.
5 | CONCLUSIONS
[18] M. Kazemi, M. Mohammadi, Appl. Organomet. Chem. 2019,
34, e5400.
[19] V. Labade, P. Shinde, M. Shingare, Tetrahedron Lett. 2013, 54,
5778.
[20] M. Nikoorazm, A. Ghorbani-Choghamarani, M. Khanmoradi,
RSC Adv. 2016, 6, 56549.
[21] K. R. Saxena, M. A. Khan, Indian J. Chem. 1989, 26, 443.
[22] T. Singh, V. K. Srivastava, S. Sharma, A. Kumar, Indian
J. Chem. 2006, 45, 2558.
[23] A. N. Gangwal, U. R. Kothawade, A. D. Galande, D. S. Pharande,
A. S. Dhake, Indian J. Heterocyl. Chem. 2001, 10, 291.
[24] R. Tyagi, B. Goel, V. K. Srivastava, A. Kumar, Indian J. Pharm.
Sci. 1998, 60, 283.
[25] A. Kumar, M. Tyagi, V. K. Srivastava, Indian J. Chem. 2003,
42, 2142.
[26] A. R. Raghu Ram, R. H. Bahekar, Indian J. Chem. 1999,
38, 434.
[27] N. Mizuno, K. Kamata, Coord. Chem. Rev. 2011, 255, 2358.
The successful preparation of the VO–vanillin-MCM-41
catalyst demonstrated that the sol–gel method as a simple
method to prepare the nanometer-sized, highly effective,
heterogeneous catalyst. The prepared catalyst was charac-
terized by different techniques and applied in the prepara-
tion of sulfoxides, disulfides, and 2,3-dihydroquinazolin-4
(1H)-one derivatives. The results showed its several advan-
tages such as high efficiency, short reaction times, general-
ity, good to excellent yield of the desired products,
simplicity, capability of carrying out oxidation reaction in
green media, ease of product isolation, avoidance of haz-
ardous solvents, and use of vanillin as ligand on the sur-
face of nPrNH2–MCM-41, which is very low cost,
nontoxic, and in general agreement with the principles of
green chemistry, as demonstrated in this paper. Further-
more, the catalyst could be recycled and reused six times

NIKOORAZM AND KHANMORADI
13
[28] A. Fuerte, M. Iglesias, F. Sanchez, A. Corma, J. Mol. Catal. A
2004, 227, 211.
[29] N. Moussa, J. M. Fraile, A. Ghorbel, J. A. Mayoral, J. Mol.
Catal. A 2006, 255, 62.
[30] N. N. Trukhan, A. Y. Derevyankin, A. N. Shmakov,
E. A. Paukshtis, O. A. Kholdeeva, V. N. Romannikov, Micropo-
rous Mesoporous Mater. 2001, 603, 44.
[41] A. Shaabani, A. H. Rezayan, Catal. Commun. 2007, 8, 1112.
[42] A. Ghorbani-Choghamarani, M. Nikoorazm, H. Goudarziafshar,
B. Tahmasbi, Bull. Korean Chem. Soc. 2009, 30, 1388.
[43] A. Ghorbani-Choghamarani, M. Nikoorazm, G. Azadi, J. Serb.
Chem. Soc. 2012, 77, 159.
[44] A. Ghorbani-Choghamarani, S. Sardari, J. Sulfur. Chem. 2011,
32, 63.
[31] B. Christian Enger, A. Lossan, O. Borg, E. Rytter, A. Holmen,
J. Catal. 2011, 284, 9.
[45] V. Polshettiwar, C. Len, A. Fihri, Coord. Chem. Rev. 2009, 253,
2599.
[32] C. Pereira, J. F. Silva, A. M. Pereira, J. P. Araujo, G. Blanco,
J. M. Pintado, C. Freire, Cat. Sci. Technol. 2011, 1, 784.
[33] A. Ghorbani-Choghamarani, M. Mohammadi, Z. Taherinia,
J. Iran. Chem. Soc. 2019, 16, 411.
[34] A. Ghorbani-Choghamarani, B. Tahmasbi, R. H. E. Hudson,
A. Heidari, Microporous Mesoporous Mater. 2019, 284, 366.
[35] M. Nikoorazm, A. Ghorbani-Choghamarani, A. Panahi,
B. Tahmasbi, N. Noori, J. Iran. Chem. Soc. 2018, 15, 181.
[36] M. Khanmoradi, M. Nikoorazm, A. Ghorbani-Choghamarani,
Catal. Lett. 2017, 147, 1114.
[46] M. Hajjami, B. Tahmasbi, RSC Adv. 2015, 5, 59194.
[47] A. V. Dhanunjaya Rao, B. P. Vykunteswararao,
T. Bhaskarkumar, N. R. Jogdand, D. Kalita, J. K. D. Lililakar,
V. Siddaiah, P. D. Sanasi, A. Raghunadh, Tetrahedron Lett.
2015, 56, 4714.
[48] A. Ghorbani-Choghamarani, Z. Darvishnejad, M. Norouzi,
Appl. Organomet. Chem. 2015, 29, 707.
How to cite this article: Nikoorazm M,
Khanmoradi M. Synthesis and characterization of
VO–vanillin complex immobilized on MCM-41 and
its facile catalytic application in the sulfoxidation
reaction, and synthesis of 2,3-dihydroquinazolin-4
(1H)-ones and disulfides in green media. J Chin
Chem Soc. 2020;1–13. https://doi.org/10.1002/jccs.
201900531
[37] M. Nikoorazm, A. Ghorbani-Choghamarani, M. Khanmoradi,
J. Iran. Chem. Soc. 2017, 14, 1215.
[38] M. Nikoorazm, A. Ghorbani-Choghamarani, F. Ghorbani,
H. Mahdavi, Z. Karamshahi, J. Porous Mater. 2015,
22, 261.
[39] A. Ghorbani-Choghamarani, M. Mohammadi, T. Tamoradi,
M. Ghadermazi, Polyhedron 2019, 158, 25.
[40] A. Ghorbani-Choghamarani, G. Azadi, B. Tahmasbi,
M. Hadizadeh-Hafshejani, Z. Abdi, Phosphorus, Sulfur Silicon
Relat. Elem. 2014, 189, 433.