Preparation of iron-containing schiff base and ionic liquid based bifunctional periodic mesoporous organosilica and its application in the synthesis of 3,4-dihydropyrimidinones

Article abstract of DOI:10.1002/cplu.201402415

A novel iron-containing Schiff base and ionic liquid based bifunctional periodic mesoporous organosilica (Fe@SBIL-BPMO) was prepared, characterized, and its catalytic application was developed. The SBIL-BPMO was first prepared by the grafting of 3-aminopr

Full text of DOI:10.1002/cplu.201402415

DOI: 10.1002/cplu.201402415
Full Papers
Preparation of Iron-Containing Schiff Base and Ionic Liquid
Based Bifunctional Periodic Mesoporous Organosilica and
Its Application in the Synthesis of 3,4-Dihydro-
pyrimidinones
Dawood Elhamifar* and Elham Nazari[a]
A novel iron-containing Schiff base and ionic liquid based bi-
functional periodic mesoporous organosilica (Fe@SBIL-BPMO)
was prepared, characterized, and its catalytic application was
developed. The SBIL-BPMO was first prepared by the grafting
of 3-aminopropyltrimethoxysilane on an ionic-liquid-based
PMO followed by treatment with 2-hydroxybenzaldehyde in
toluene at reflux. This material was then reacted with
Fe(NO3)3·9H2O to afford the Fe@BPMO-SBIL nanocatalyst. The
catalyst was characterized by thermogravimetric analysis, nitro-
gen sorption experiments, diffuse reflectance FTIR spectrosco-
py, low-angle powder XRD, and TEM. The Fe@SBIL-BPMO cata-
lyst was successfully applied in the one-pot synthesis of 3,4-di-
hydropyrimidinone/thione derivatives under solvent-free reac-
tions. The stability, reactivity, and reusability of the catalyst
under the reaction conditions have also been investigated.
Introduction
The metal-catalyzed synthesis of 3,4-dihydropyrimidinones/thi-
ones through the Biginelli reaction is an important and valua-
ble chemical process that is of particular interest owing to its
key role in the production of drugs applicable in different
areas of pharmacology.[1,2] Some pharmaceutical properties of
these compounds include anticancer, anti-HIV, calcium channel
modulator, antihypertensive, antitumor, antibacterial, antioxi-
dant, and antiviral activities.[3] Traditionally, the Biginelli reac-
tion was performed under homogeneous conditions in the
presence of many metal-based Lewis acid catalysts. Some im-
proved catalysts include La(OTf)3 (OTf=triflate), ZnCl2, ZnBr2,
CuCl2, NiCl2, ZnI2, VCl3, LiClO4, Sr(OTf)2, BF3·OEt2, FeCl3, LaCl3,
InX3 (X=Cl, Br), BiCl3, Yb(OTf)3, ZrCl4, Mn(OAc)3, Cu(OTf)2,
Cu(OAc)2, LaCl3–graphite, LiBr, GaX3, and [bmim][FeCl4]
(bmim=1-butyl-3-methylimidazolium).[1,2] However, because
these homogeneous catalytic systems are usually expensive,
toxic, and require large amounts of unrecoverable catalyst, on
the basis of economic criteria and toxicological concerns, it is
more desirable to reduce the amounts of metal-based catalyst
used in potential chemical processes. To overcome these re-
strictions, several improvements were recently attempted by
immobilization or supporting metal catalysts on different reus-
able and recoverable surfaces such as silica, alumina, polymers,
and resin.[4] Nevertheless, some of these processes suffer from
environmental pollution caused by the utilization of organic
solvents, exotic reaction conditions, long reaction times, and
most importantly high loading and leaching of the catalyst
during the reaction. Accordingly, the development of efficient
and environmentally friendly metal-based catalytic systems
that are easily prepared, recoverable, and reusable is still
needed for the Biginelli reaction.
On the other hand, metal-containing hybrid organic–inor-
ganic materials are a significant topic that has attracted much
attention from chemists owing to the metal possessing excel-
lent catalytic activity and the possibility of easy recovery and
reuse.[5] The preparation of these materials is achieved by the
impregnation of metallic complexes with supports containing
a suitable ligand and/or by simultaneous cocondensation of
a metal–ligand complex with a hydrolysable and condensable
organic/inorganic precursor under acidic or basic conditions.[5]
In particular, metal-containing ordered mesoporous organosili-
ca (M@OMO) materials are more interesting owing to advan-
tages of high surface area, easy diffusion of organic substrates
for typical transformations, as well as high thermal and me-
chanical stability.[6] A valuable achievement in this area is the
creation and applications of the periodic mesoporous organo-
silica-supported metal catalyst (M@PMO) with excellent stabili-
ty of the catalytic centers and organic moieties.[7] Accordingly,
several M@PMO materials have been recently prepared and
their catalytic applications have been successfully applied in
a number of organic transformations.[7–10] For example, recently
we prepared and developed some metal-containing periodic
mesoporous organosilicas with an ionic-liquid framework
(M@PMO-IL; M=Pd, Ru, Cu, Mn, WO42À) and studied their ap-
plications in oxidation and cross-coupling reactions.[10] Our
studies demonstrated that PMO-IL was a powerful and highly
[a] Dr. D. Elhamifar, E. Nazari
Department of Chemistry
Yasouj University
Yasouj 75918-74831 (Iran)
Fax: (+98)741-33223048
E-mail: d.elhamifar@yu.ac.ir
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/cplu.201402415.
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sorption–desorption analysis of
all PMO-IL, SBIL-BPMO, and
Fe@SBIL-BPMO samples exhibit-
ed type IV isotherms with clear
H1 hysteresis loops at high rela-
tive pressures and a vertical ca-
pillary condensation step at P/P0
ꢀ0.7–0.8; this indicated that
the materials had very regular
mesochannels, which is a charac-
teristic of large-pore mesopo-
rous materials with a uniform
2D
hexagonal
structure
(Figure 1). In addition, all sam-
ples possessed narrow BJH pore
size distributions; however, for
SBIL-BPMO and Fe@SBIL-BPMO
the pore size of the mesostruc-
ture decreased from 10.5 to
9.3 nm. Moreover, after func-
tionalization
with
ortho-
hydroxybenzaldehyde, followed
by treatment with the iron com-
plex, the BET surface area and
Scheme 1. Preparation of the Fe@SBIL-BPMO nanocatalyst and its application
in the synthesis of 3,4-dihydropyrimidinones/thiones.
stable support for metal complexes and could be recovered
several times with retention of efficiency. As a continuation of
these studies, herein we wish to disclose a protocol for the
preparation a novel iron-containing Schiff base and ionic liquid
based bifunctional PMO (Fe@SBIL-BPMO) nanocatalyst and
a study on its performance in the one-pot, three-component
Biginelli condensation of aldehydes, urea/thiourea, and alkyl
acetoacetate (Scheme 1). The effect of the SBIL-BPMO support
on the immobilization, stabilization, and reactivity of metallic
catalytic sites during the reaction process has also been inves-
tigated.
Results and Discussion
The preparation of Fe@SBIL-BPMO was achieved by immobili-
zation of Fe(NO3)3·9H2O on a novel BPMO material. First, the
ionic-liquid-based periodic mesoporous organosilica (PMO-IL)
was prepared according to our previous procedure.[10] This was
then reacted with 3-aminopropyltrimethoxy silane by a grafting
approach to give the aminopropyl-functionalized PMO nano-
material (PMO-IL-NH2). Next, PMO-IL-NH2 was treated with 2-
hydroxybenzaldehyde in toluene at reflux to produce Schiff
base and ionic liquid based bifunctional PMO (SBIL-BPMO). Fi-
nally, Fe@SBIL-BPMO was obtained by treatment of SBIL-BPMO
with a substoichiometric amount of Fe(NO3)3·9H2O (Scheme 1).
This catalyst was characterized by diffuse reflectance infrared
Fourier transform spectroscopy (DRIFTS), thermogravimetric
analysis (TGA), nitrogen-sorption experiments, low-angle
powder X-ray diffraction (LAPXRD), and TEM. The nitrogen ad-
Figure 1. Nitrogen adsorption–desorption (a) and Barrett–Joyner–Halenda
(BJH) pore size distribution (b) isotherms of the PMO-IL, SBIL-BPMO, and
Fe@SBIL-BPMO nanomaterials.
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pore volume decreased in the order of PMO-IL>SBIL-BPMO>
Fe@SBIL-BPMO (Table 1), but the isotherm pattern remained
unchanged. These results confirm the successful immobiliza-
tion of the ortho-hydroxybenzaldehyde ligand and iron com-
Table 1. Structural parameters of PMO-IL, SBIL-BPMO, and Fe@SBIL-BPMO
materials determined from nitrogen-sorption experiments.
Sample
BET surface
area [m2 gÀ1
Pore diameter
[nm]
Pore volume
[cm3 gÀ1
]
]
PMO-IL
SBIL-BPMO
Fe@SBIL-BPMO
645
518
478
10.5
9.3
9.3
1.15
0.93
0.82
Figure 2. TEM image of the Fe@SBIL-BPMO nanocatalyst.
plex inside the channels of the mesoporous PMO-IL material
without disturbing its periodic nature. TEM analysis and
LAPXRD of the Fe@SBIL-BPMO catalyst were next performed to
verify the periodicity of the pores. According to the TEM
image, when the electron beam was introduced perpendicular-
ly to the channel axis, a parallel alignment of channels was ob-
served (Figure 2), whereas hexagonal packing of the cylindrical
mesopore was revealed when the electron beam was intro-
duced along the channel axis (Figure 2, inset). The LAPXRD re-
sults for the catalyst also illustrated a diffraction peak with
high intensity at 2q=0.98, which was indexed to the d100 re-
flection (Figure 3). The d110 and d200 reflections were also ob-
served at 2q=1.5 and 1.78, respectively; this confirmed that
the material possessed a highly ordered hexagonal mesostruc-
ture. Moreover, these analyses together with the results from
nitrogen-sorption experiments showed that, after loading of 2-
hydroxybenzalehyde and the iron complex, the structural in-
tegrity and order of the mesochannels were maintained, which
proved the high mechanical stability of the material.
TGA of Fe@SBIL-BPMO was also performed to validate the
thermal stability of the catalyst. This analysis was performed
from room temperature to 8008C (Figure 4), and revealed
three weight losses at different
Figure 3. LAPXRD results for the Fe@SBIL-BPMO catalyst.
The presence of organic functional groups in the material
network was confirmed by DRIFTS (Figure 5). The strong bands
at n˜ =1145, 1076, and 956 cmÀ1 are attributed to asymmetric
temperature ranges. The first
one from 10 to 1108C (6.04%) is
attributed to removal of water
and alcoholic solvents remain-
ing from the synthetic process.
The second one between 110
and 3008C (5.07%) corresponds
to elimination of the surfactant
template remaining from the
synthetic process. The main
weight loss appearing between
301 and 8008C (24.45%) is relat-
ed to propyl Schiff base and
ionic-liquid groups located in
the surface and body of the ma-
terial network. These data prove
the high thermal stability of the
material.
Figure 4. TGA results for the Fe@SBIL-BPMO nanocatalyst.
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zation of alkyl imidazolium ionic
liquid and Schiff base groups in
the material framework.
After characterization, the
performance of the Fe@SBIL-
BPMO nanocatalyst was investi-
gated in the one-pot, three-
component condensation of
benzaldehyde, methyl acetoace-
tate, and urea as a test model
(Table 2). In the first study, the
effect of solvent was studied: in
toluene, a low yield was ob-
tained, whereas in H2O, EtOH,
and CH3CN a moderate yield of
the desired coupling product
was obtained (Table 2, en-
tries 1–4). This may be attribut-
ed to the low solubility of the
starting materials in the tolu-
ene. Importantly, under solvent-
free media, a quantitative yield
of product was obtained
(Table 2, entry 5). The reaction
was also affected by the catalyst
loading and the best result was
observed in the presence of
0.8 mol% of catalyst (Table 2,
entries 5–7). The reaction prog-
ress was also strongly affected
by temperature. The reaction
was very slow and gave low to
moderate yields of the product
at 30 and 608C, but was accel-
erated with increasing tempera-
ture, and at 808C gave quantita-
tive yield (Table 2, entry 5 vs.
entries 8 and 9).
With the optimized condi-
tions in hand, the scope and
Figure 5. DRIFTS results for the PMO-IL (a) and Fe@SBIL-BPMO (b) nanomaterials.
Table 2. The effect of solvent, temperature, and catalyst loading in the
Biginelli reaction of benzaldehyde with urea and methyl acetoacetate in
the presence of Fe@SBIL-BPMO.[a]
and symmetric stretching vibrations of SiÀOÀSi bonds.[10c] In
addition, the strong and broad band appearing at n˜ =3200–
3500 cmÀ1 is due to the stretching vibration of OÀH bonds.
Moreover, the absorption bands of organic functional groups
are observed at n˜ =3125 (for unsaturated CÀH stretching),
2927 and 2855 (CÀH stretching of aliphatic moieties), 1637
(C=N stretching of Schiff base and imidazolium ring),[4g,10c]
1457 (CÀH deformation vibrations), 797 (for CÀSi stretching vi-
brations), and 455 cmÀ1 (bending vibration of SiÀOÀSi). Inter-
estingly, for Fe@SBIL-BPMO, the intensity of the C=N band (n˜ =
1637 cmÀ1) is increased, which proves that the 2-hydroxyben-
zaldehyde functional group is chemically bound in the meso-
channels of PMO-IL.[4g] These data are in good agreement with
TGA results and confirm the successful inclusion and immobili-
Entry
Catalyst loading [mol%]
T [oC]
Solvent
Yield [%][b]
1
2
3
4
5
6
7
8
9
0.8
0.8
0.8
0.8
0.8
0.5
0.3
0.8
0.8
80
80
80
80
80
80
80
60
30
H2O
EtOH
CH3CN
toluene
–
–
–
–
–
58
68
76
8
97
55
30
54
9
[a] Reaction conditions: benzaldehyde (1 mmol), methyl acetoacetate
(1 mmol), urea (1.5 mmol), 50 min. [b] Yields of product isolated.
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generality of this protocol were then demonstrated by testing
a broad range of substrates, and the results showed that the
presence of either electron-withdrawing or -donating substitu-
ents on the aldehydes did not have a significant effect on their
reactivity or product yield. As shown in Table 3, benzaldehyde,
with both urea and thiourea, delivered a quantitative yield of
the corresponding coupling adducts under the optimized reac-
tion conditions and in short times (Table 3, entries 1–4).
optimized conditions, then the catalyst was removed by filtra-
tion, and the reaction was allowed to proceed without catalyst.
There was no change in the yield, even after heating at 808C
for 120 min; this indicated that no homogeneous catalyst was
involved. Moreover, atomic adsorption spectroscopy (AAS) per-
formed for the filtrate showed that the amount of leached iron
was less than 1 ppm. These results illustrate that the catalyst
may operate in a heterogeneous manner. These observations
may be attributed to Schiff base and ionic-liquid ligands,
which strongly immobilize active catalytic iron species during
the applied reaction conditions and protect them from leach-
ing and deactivation.
Table 3. Preparation of Biginelli products in the presence of the Fe@SBIL-
BPMO nanocatalyst.[a]
Because the reusability of the catalysts is an important bene-
fit and makes them useful for commercial applications, in an-
other experiment the reactivity and reusability of the present
catalyst was studied in the reaction of benzaldehyde, methyl
acetoacetate, and urea (Figure 6). To determine the recoverabil-
Entry
Ar
R
t [min]
Yield [%][b] (TON)[c]
M.p. [8C]
1
2
3
4
5
6
7
8
C6H5
C6H5
C6H5
C6H5
OMe
OEt
OMe
OEt
OMe
OEt
OMe
OEt
OEt
OEt
OMe
OEt
OMe
OEt
50
50
65
65
50
65
50
50
65
80
55
55
80
80
70
70
95
120
97 (121.25)
95 (118.75)
94 (117.5)
94 (117.5)
95 (118.75)
93 (116.25)
95 (118.75)
96 (120)
208–212
203–206
222–224[d]
206–207[d]
190–192
148–150[d]
205–207
213–215
190–193[d]
257–258
214–217
195–197
251–253
213–215
209–210
208–211
203–205
233–235
4-MeOC6H4
4-MeOC6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
2-MeOC6H4
3-BrC6H4
3-BrC6H4
2-ClC6H4
2-ClC6H4
3-ClC6H4
4-ClC6H4
4-CNC6H4
4-NO2C6H4
9
96 (120)
10
11
12
13
14
15
16
17
18
86 (107.5)
94 (117.5)
93 (116.25)
83 (103.75)
85 (106.25)
91 (113.75)
92 (115)
OMe
OEt
OEt
85 (106.25)
83 (103.75)
OMe
[a] Reaction conditions: aldehyde (1 mmol), ethyl/methyl acetoacetate
(1 mmol), urea/thiourea (1.5 mmol). [b] Yield of products isolated.
[c] TON=turnover number (defined as mmol of product/mmol of cata-
lyst). [d] Thiourea was used instead of urea.
Figure 6. Recoverability and reusability of the Fe@SBIL-BPMO nanocatalyst.
ity and reusability, after completion of the reaction, the reac-
tion mixture was filtered and washed completely with ethanol
to recover the catalyst. The recovered catalyst was dried and
then used again in the same reaction; this led to a yield of
96%. Further investigations showed that the catalyst could be
recovered and reused at least eight times without any consid-
erable loss in efficiency under the same conditions as those
used for the run with fresh catalyst.
Moreover, electron-donating substituents containing alde-
hydes, such as 4-methoxybenzaldehyde, 4-methylbenzalde-
hyde, and 2-methoxybenzaldehyde (Table 3, entries 5–10) gave
high to excellent yields of the desired products under the opti-
mized conditions. Aromatic aldehydes with electron-withdraw-
ing groups, such as 3-bromobenzaldehyde, 2-chlorobenzalde-
hyde, 3-chlorobenzaldehyde, 4-chlorobenzaldehyde, 4-cyano-
benzaldehyde, and 4-nitrobenzaldehyde, also delivered high
yields of the corresponding products (Table 3, entries 11–18). It
is also important to note that sterically demanding ortho-sub-
stituted aromatic aldehydes were used and tolerated high
yields of the corresponding products (Table 3, entries 10, 13,
and 14). These observations prove the efficiency of the catalyst
for the preparation of different derivatives of Biginelli com-
pounds that are important for drug synthesis. To prove wheth-
er the catalyst acts hetero- or homogeneously, a standard
leaching experiment was conducted for the condensation of
benzaldehyde, urea, and methyl acetoacetate as a test model.
To do this, the reaction was performed for 30 min under the
In addition, the reactivity of the catalyst was also investigat-
ed. For this, after completion of the reaction in the first run,
fresh substrates were added to the previous reaction mixture
in the same flask and stirring was performed to complete the
second cycle. These cycles occurred at least 15 times without
a noticeable decrease in the catalyst reactivity, although longer
reaction times than those used for the first run were required
(Table 4). These data strongly confirm the powerful reactivity,
reusability, and durability of the catalyst during the applied
conditions.
TEM analysis of the recovered catalyst after five cycles was
also performed to investigate the stability of the catalyst meso-
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tions of the catalyst in other chemical processes are underway
in our laboratory.
Table 4. Reactivity of the Fe@SBIL-BPMO catalyst in the Biginelli reaction
of benzaldehyde with methyl acetoacetate and urea.
Run
t [min]
Run
t [min]
Run
t [min]
1
2
3
4
5
45
45
55
60
60
6
7
8
9
65
70
70
75
75
11
12
13
14
15
80
80
80
85
90
Experimental Section
Preparation of PMO-IL-NH2
First, the PMO-IL material was prepared according to our previous-
ly reported procedure.[10] This was then modified with 3-aminopro-
pyltrimethoxyslane through a grafting approach. Typically, PMO-IL
(1 g) was added to a flask containing dry toluene (50 mL) at 258C
and stirred for about 5 min. After complete dispersion of PMO-IL in
toluene, 3-aminopropyltrimethoxysilane (0.5 mmol) was added and
the mixture was heated at reflux under an argon atmosphere for
24 h.[11] The obtained precipitate was filtered and completely
washed with ethanol to remove unreacted aminopropyltrimethoxy-
silane. The final material was dried for 12 h at 708C to give PMO-
IL-NH2 as a white powder.
10
structure. This showed a pore structure with uniform, regular
2D symmetry that was the same as that of the fresh catalyst
(Figure 7). These results are in good agreement with recovery
data and successfully confirm the superior structural stability
of the catalyst during the reaction conditions.
Preparation of SBIL-BPMO
SBIL-BPMO was prepared by the reaction of PMO-IL-NH2 with 2-hy-
droxybenzaldehyde in toluene at reflux. Typically, PMO-IL-NH2 (1 g)
was added to a round-bottomed flask containing dry toluene
(50 mL) and stirred at room temperature. After complete dispersion
of PMO-IL-NH2, 2-hydroxybenzaldehyde (0.6 mmol) was added and
the mixture was heated at reflux for 24 h. The obtained precipitate
was then filtered and completely washed with ethanol to remove
unreacted 2-hydroxybenzaldehyde. The resulting solid was dried at
708C for 12 h to give SBIL-BPMO.
Preparation of Fe@SBIL-BPMO
The Fe@SBIL-BPMO nanocatalyst was prepared by the treatment of
SBIL-BPMO with a substoichiometric amount of Fe(NO3)3·9H2O in
DMSO. SBIL-BPMO (1 g) was added to a flask containing DMSO
(5 mL) and stirred at room temperature. After complete dispersion
of SBIL-BPMO, Fe(NO3)3·9H2O (0.7 mmol) was added and the result-
ing mixture was stirred at 258C for 12 h and then at 1008C for 2 h.
After cooling the reaction solution to room temperature, the ob-
tained mixture was filtered and completely washed with ethanol
to remove unsupported Fe(NO3)3·9H2O. The obtained Fe@SBIL-
BPMO powder was next dried at 708C for 12 h under vacuum. Ele-
mental analysis showed that the loading of Fe on the solid materi-
al was 0.38 mmol Fe per gram.
Figure 7. TEM image of the recovered Fe@SBIL-BPMO catalyst after the fifth
cycle.
Conclusion
A novel Fe@SBIL-BPMO catalyst was prepared, characterized,
and its catalytic performance was developed in the Biginelli re-
action. DRIFTS and TGA strongly confirmed the successful in-
corporation and stabilization of ionic-liquid and Schiff base
groups in the material framework. The nitrogen adsorption–de-
sorption analysis, PXRD, and TEM results also showed the pres-
ence of a uniform, highly regular 2D structure for the catalyst.
This novel nanocatalyst illustrated the high reactivity and selec-
tivity for the preparation of various derivatives of dihydropyri-
midinones/thiones through the Biginelli reaction under sol-
vent-free conditions. Moreover, this catalyst was successfully
reused and recovered for several consecutive runs, and re-
tained its catalytic efficiency and selectivity. A TEM image of
the recovered catalyst confirmed the high structural stability of
the material under the applied reaction conditions. Some
other advantages of this study were simple workup, easy cata-
lyst recovery, high yields of products, and low catalyst loading.
According to the aforementioned advantages, some applica-
General procedure for the preparation of Biginelli products
by using the Fe@SBIL-BPMO nanocatalyst
For this, Fe@SBIL-BPMO nanocatalyst (0.8 mol%) was added to
a flask containing a homogeneous mixture of aldehyde (2 mmol),
alkyl acetoacetate (2 mmol), and urea/thiourea (3 mmol). The ob-
tained solution was then magnetically stirred under solvent-free
conditions at 808C for an appropriate time, as indicated in Table 2.
The reaction progress was monitored by TLC. After completion of
the reaction, warm ethanol (8 mL) was added and the reaction
mixture was separated from the catalyst by filtration and washing
with warm ethanol. The filtrate was then placed in an ice bath to
precipitate crude crystals. Finally, pure products were obtained
after recrystallization in ethanol.
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Rani, N. Srinivas, M. R. Kishan, S. J. Kulkarni, K. V. Raghavan, Green Chem.
2001, 3, 305–306; d) I. S. Zorkun, S. Sarac, S. Celebib, K. Erolb, Bioorg.
Med. Chem. 2006, 14, 8582–8589; e) L. M. Ramos, A. Tobio, M. R. dos
Santos, H. C. B. de Oliveira, A. F. Gomes, F. C. Gozzo, A. L. de Oliveira,
B. A. D. Neto, J. Org. Chem. 2012, 77, 10184–10193; f) X.-L. Shi, H. Yang,
M. Tao, W. Zhang, RSC Adv. 2013, 3, 3939–3945; g) P. K. Sahu, D. D.
Agarwal, RSC Adv. 2013, 3, 9854–9864.
General procedure for the recovery of the Fe@SBIL-BPMO
nanocatalyst in the Biginelli reaction
The Fe@SBIL-BPMO nanocatalyst (0.8 mol%) was added to a flask
containing a homogeneous solution of aldehyde (5 mmol), alkyl
acetoacetate (5 mmol), and urea (7.5 mmol), and the mixture was
magnetically stirred at 808C. The reaction progress was monitored
by TLC. After the reaction was completed, warm ethanol (10 mL)
was added and the obtained solution was hot filtered. The catalyst
was separated from the reaction mixture by further washing with
warm ethanol. This catalyst was reused at least eight times under
the same conditions as those used for the first run, and delivered
the corresponding 3,4-dihydropyrimidinone product in high yield
and selectivity.
[4] a) S. Martꢁnez, M. Meseguer, L. Casas, E. Rodrꢁguez, E. Molins, M. M.
MaÇas, A. Roig, R. M. Sebastiꢂn, A. Vallribera, Tetrahedron 2003, 59,
1553–1556; b) J. Azizian, A. A. Mohammadi, A. R. Karimi, M. R. Moham-
madizadeh, App. Catal. A: Gen. 2006, 300, 85–88; c) S. L. Jain, J. K.
Joseph, S. Singhal, B. Sain, J. Mol. Catal. A: Chem. 2007, 268, 134–138;
d) S. L. Jain, V. V. D. N. Prasad, B. Sain, Catal. Commun. 2008, 9, 499–
503; e) P. Li, S. Regati, R. J. Butcher, H. D. Arman, Z. Chen, S. Xiang, B.
Chen, C.-G. Zhao, Tetrahedron Lett. 2011, 52, 6220–6222; f) J. Mondal, T.
Sen, A. Bhaumik, Dalton Trans. 2012, 41, 6173–6181; g) R. K. Sharma, D.
Rawat, Inorg. Chem. Commun. 2012, 17, 58–63; h) R. Tayebee, M. M.
Amini, M. Ghadamgahi, M. Armaghan, J. Mol. Catal. A: Chem. 2013, 366,
266–274; i) F. Zamani, S. M. Hosseini, S. Kianpour, Solid State Sci. 2013,
26, 139–143; j) G. R. Chaudhary, P. Bansal, S. K. Mehta, Chem. Eng. J.
2014, 243, 217–224; k) A. Dhakshinamoorthy, H. Garcia, Chem. Soc. Rev.
2014, 43, 5750–5765.
General procedure for the reactivity of the Fe@SBIL-BPMO
nanocatalyst in the Biginelli reaction
Fe@SBIL-BPMO nanocatalyst (0.8 mol%) was added to a flask con-
taining benzaldehyde (2 mmol), ethyl acetoacetate (2 mmol), and
urea (3 mmol), and the mixture was stirred at 808C under solvent-
free conditions. After completion of the reaction, as monitored by
TLC, the starting materials without catalyst (benzaldehyde
(2 mmol), ethyl acetoacetate (2 mmol), and urea (2 mmol)) were
added and the reaction progress was monitored under the same
conditions as those used in the first run (solvent free, 808C). After
completion of the reaction, the latter process was repeated at least
14 times without a significant decrease in the activity of the cata-
lyst.
[5] a) A. P. Wight, M. E. Davis, Chem. Rev. 2002, 102, 3589–3614; b) A. Stein,
Adv. Mater. 2003, 15, 763–775.
[6] a) D. Y. Zhao, D. J. Goldfard, J. Chem. Soc. Chem. Commun. 1995, 875–
876; b) B. J. Aronson, C. F. Blanford, A. Stein, Chem. Mater. 1997, 9,
2842–2851; c) J. Xu, Z. Luan, M. Hartman, L. Kevan, Chem. Mater. 1999,
11, 2928–2936; d) M. Frçba, R. Kçhn, B. Gaellꢃ, Chem. Mater. 1999, 11,
2858–2865; e) V. Caps, S. C. Tsang, Catal. Today 2000, 61, 19–27; f) C.
Pak, G. L. Haller, Microporous Mesoporous Mater. 2001, 48, 165–170;
g) R. Radhakrishnan, T. S. Oyama, J. G. Chen, K. Asakura, J. Phys. Chem. B
2001, 105, 4245–4253; h) E. P. Reddy, J. Phys. Chem. B 2002, 106, 3394–
3401; i) N. Lang, P. Delichere, A. Tuel, Microporous Mesoporous Mater.
2002, 56, 203–217; j) K. Dhara, K. Sarkar, D. Srimani, S. K. Saha, P. Chat-
topadhyay, A. Bhaumik, Dalton Trans. 2010, 39, 6395–6402; k) U. Dꢁaz,
D. Brunel, A. Corma, Chem. Soc. Rev. 2013, 42, 4083–4097.
Acknowledgements
[7] a) B. Hatton, K. Landskron, W. Whitnall, D. Perovic, G. A. Ozin, Acc. Chem.
Res. 2005, 38, 305–312; b) F. Hoffmann, M. Cornelius, J. Morell, M.
Frçba, Angew. Chem. Int. Ed. 2006, 45, 3216–3251; Angew. Chem. 2006,
118, 3290–3328; c) S. Fujita, S. Inagaki, Chem. Mater. 2008, 20, 891–
908; d) Q. Yang, J. Liu, L. Zhang, C. Li, J. Mater. Chem. 2009, 19, 1945–
1955; e) S. El Hankari, B. Motos-Pꢄrez, P. Hesemann, A. Bouhaouss,
J. J. E. Moreau, Chem. Commun. 2011, 47, 6704–6706; f) F. Hoffmann, M.
Frçba, Chem. Soc. Rev. 2011, 40, 608–620.
We acknowledge the Yasouj University and Iran National Science
Foundation (INSF) for supporting this study. We also thank
Prof. Dr. B. Karimi (from IASBS) for his kind help with the TGA
and nitrogen-sorption analyses.
Keywords: ionic liquids · iron · nanostructures · Schiff bases ·
supported catalysts
[8] M. Waki, N. Mizoshita, T. Tani, S. Inagaki, Angew. Chem. Int. Ed. 2011, 50,
11667–11671; Angew. Chem. 2011, 123, 11871–11875.
[9] a) C. Baleiz¼o, B. Gigante, D. Das, M. ꢅlvaro, H. Garcia, A. Corma, J. Catal.
2004, 223, 106–113; b) M. Nandi, P. Roy, H. Uyama, A. Bhaumik, Dalton
Trans. 2011, 40, 12510–12518; c) S. Verma, M. Nandi, A. Modak, S. L.
Jain, A. Bhaumik, Adv. Synth. Catal. 2011, 353, 1897–1902; d) A. Modak,
J. Mondal, A. Bhaumik, Green Chem. 2012, 14, 2840–2855.
[10] a) B. Karimi, D. Elhamifar, J. H. Clark, A. J. Hunt, Chem. Eur. J. 2010, 16,
8047–8053; b) B. Karimi, D. Elhamifar, J. H. Clark, A. J. Hunt, Org. Biomol.
Chem. 2011, 9, 7420–7426; c) B. Karimi, D. Elhamifar, O. Yari, M. Khora-
sani, H. Vali, J. H. Clark, A. J. Hunt, Chem. Eur. J. 2012, 18, 13520–13530;
d) D. Elhamifar, B. Karimi, J. Rastegar, M. H. Banakar, ChemCatChem
2013, 5, 2418–2424; e) B. Karimi, M. Gholinejad, M. Khorasani, Chem.
Commun. 2012, 48, 8961–8963; f) D. Elhamifar, A. Shꢂbani, Chem. Eur. J.
2014, 20, 3212–3217; g) B. Karimi, F. Bakhshandeh Rostami, M. Khorasa-
ni, D. Elhamifar, H. Vali, Tetrahedron 2014, 70, 6114–6119; h) D. Elhami-
far, F. Hosseinpoor, B. Karimi, S. Hajati, Microporous Mesoporous Mater.
2015, 204, 269–275; i) M. Nasr-Esfahani, D. Elhamifar, T. Amadeh, B.
Karimi, RSC Adv. 2015, 5, 13087–13094.
[1] a) C. O. Kappe, Acc. Chem. Res. 2000, 33, 879–888; b) M. Syamala, Org.
Prep. Proced. Int. 2009, 41, 1–68; c) Suresh, J. S. Sandhu, Arkivoc 2012, i,
66–133.
[2] a) K. Ananda Kumar, M. Kasthuraiah, C. Suresh Reddy, C. D. Reddy, Tetra-
hedron Lett. 2001, 42, 7873–7875; b) G. Maiti, P. Kundu, C. Guin, Tetrahe-
dron Lett. 2003, 44, 2757–2758; c) A. S. Paraskar, G. K. Dewkar, A. Suda-
lai, Tetrahedron Lett. 2003, 44, 3305–3308; d) N. Fu, Y. Yuan, M. Pang, J.
Wang, C. Peppe, J. Organomet. Chem. 2003, 672, 52–57; e) M. A. P. Mar-
tins, M. V. M. Teixeira, W. Cunico, E. Scapin, R. Mayer, C. M. P. Pereira, N.
Zanatta, H. G. Bonacorso, C. Peppe, Y. F. Yuan, Tetrahedron Lett. 2004,
45, 8991–8994; f) G. Jenner, Tetrahedron Lett. 2004, 45, 6195–6198; g) I.
Cepanec, M. Litvic, A. Bartolincic, M. Lovric, Tetrahedron 2005, 61, 4275–
4280; h) H. El Badaoui, F. Bazi, R. Tahir, H. B. Lazrek, S. Sebti, Catal.
Commun. 2005, 6, 455–458; i) S. L. Jain, J. K. Joseph, B. Sain, Catal. Lett.
2007, 115, 52–55; j) Y. Yu, D. Liu, C. Liu, H. Jiang, G. Luo, Prep. Biochem.
Biotechnol. 2007, 37, 381–387; k) A. Saini, S. Kumar, J. S. Sandhu, Indian
J. Chem. 2007, 46B, 1886–1889; l) H. Khabazzadeh, K. Saidi, H. Sheibani,
Bioorg. Med. Chem. Lett. 2008, 18, 278–280; m) X. Chen, Y. Peng, Catal.
Lett. 2008, 122, 310–313.
[11] D. Elhamifar, B. Karimi, A. Moradi, J. Rastegar, ChemPlusChem 2014, 79,
1147–1152.
[3] a) L. E. Overman, M. H. Rabinowitz, P. A. Renhowe, J. Am. Chem. Soc.
1995, 117, 2657–2658; b) T. U. Mayer, T. M. Kapoor, S. J. Haggarty, R. W.
King, S. L. Schreiber, T. J. Mitchison, Science 1999, 286, 971–974; c) R. V.
Received: December 1, 2014
Published online on && &&, 0000
ChemPlusChem 0000, 00, 0 – 0
www.chempluschem.org
7
ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
These are not the final page numbers! ÞÞ

FULL PAPERS
D. Elhamifar,* E. Nazari
&& – &&
Preparation of Iron-Containing Schiff
Base and Ionic Liquid Based
Bifunctional Periodic Mesoporous
Organosilica and Its Application in the
Synthesis of 3,4-Dihydro-
pyrimidinones
Hard graft: A novel iron-containing
Schiff base and ionic liquid based bi-
functional periodic mesoporous organo-
silica (Fe@SBIL-BPMO) was prepared and
characterized, and its catalytic applica-
tion was investigated in the one-pot
three-component Biginelli reaction (see
picture). The catalyst illustrated excel-
lent reactivity, recoverability, and reusa-
bility under the applied conditions.
&
ChemPlusChem 0000, 00, 0 – 0
www.chempluschem.org
8
ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!