S. Rostamizadeh et al. / Journal of Molecular Catalysis A: Chemical 374–375 (2013) 102–110
103
O
O
R
( -Fe O )-MCM-41-L-Prolinium nitrate
α
2
3
N
O
X
+
RNH2
+
Ar
Solvent Free, 100 °C
N
Ar
N
H
O
X= CHO , CH2Cl
4
3
1
2
Scheme 1. (␣-Fe2O3)-MCM-41-l-prolinium nitrate as a magnetic nanocatalyst for the synthesis of quinazolin-4(3H)-one derivatives.
many of the reported methods stoichiometric or excess amounts
of oxidants such as DDQ [15], CuCl2 [16], MnO2 [17], KMnO4 [18],
I2/KI [19], Yb(OTf)3 [20], and solvent as oxidant [21] have been used.
Filling of the mesochannels in mesoporous materials with ILs
was previously reported to improve the catalyst performance and
selectivity in the metal-free aerobic oxidations [22]. So, this idea
prompted us to examine the possibility of utilizing ILs along with
mesoporous magnetic MCM-41 materials in order to apply in the
synthesis of valuable heterocyclic compounds such as quinazolin-
4(3H)-one derivatives.
Then sodium silicate (16 mL) was added, and the mixture was
allowed to react at room temperature for 24 h under well-mixed
conditions. The magnetic MCM-41 [(Fe3O4)-MCM-41] was filtered
and washed with alcoholic ammonium nitrate. The surfactant
template was then removed from the synthesized material by
calcination at 450 ◦C for 4 h to give the [(␣-Fe2O3)-MCM-41]. It is
worth mentioning that in the absence of nitrogen the magnetic
property of Fe3O4 is decreased.
2.2. Preparation of (˛-Fe2O3)-MCM-41-l-prolinium nitrate
Herein, we wish to introduce the novel (␣-Fe2O3)-MCM-41
nanocatalyst in which l-prolinium nitrate ionic liquid has been
bound to the internal surface of the mesochannels of mesoporous
catalytic performance in direct synthesis of quinazolin-4(3H)-one
derivatives 4 from isatoic anhydride 1, primary amines 2 and an
aldehyde or an aryl halide 3, at 100 ◦C with good to excellent yields
of the products within short reaction times (Scheme 1). We present
the synthesis of quinazolin-4(3H)-one derivatives in the absence of
any other extra oxidant for the first time.
A mixture of (␣-Fe2O3)-MCM-41 (1 g) and l-prolinium nitrate
(0.71 g, 4 mmol) in 5 mL dry acetone was stirred at room temper-
ature for 3 h, the solvent was then removed in vacuo and washed
with CH2Cl2 to give (␣-Fe2O3)-MCM-41-l-prolinium nitrate as a
brown powder.
2.3. General experimental procedure for the synthesis of
quinazolin-4(3H)-one derivatives in the presence of
(˛-Fe2O3)-MCM-41-l-prolinium nitrate
A mixture of isatoic anhydride (1 mmol), aldehyde or benzyl
halide (1 mmol), ammonium acetate (2 mmol) or aniline deriva-
tives (1 mmol) and the catalyst (0.03 gr) was ground thoroughly
and then transferred into a reaction vessel where this mixture was
stirred under 100 ◦C for the appropriate time. The reactions were
monitored by TLC (EtOAc:Petroleum ether, 1:2). After completion
of the reaction, the mixture was allowed to be cooled down to
room temperature. Then chloroform (10 mL) was added and the
mixture was stirred for an extra 30 min. After collecting the mag-
netic catalyst with an external magnet, MeOH (1 mL) was added
to the chloroform solution and this solution was then concentrated
in vacuo until the precipitates were formed. The products were vac-
2. Experimental
Melting points were recorded on a Buchi B-540 apparatus. IR
spectra were recorded on an ABB Bomem Model FTLA200-100
instrument.
1H and 13C NMR spectra were measured on a Bruker DRX-
300 spectrometer, at 400 and 100 MHz, using TMS as an internal
standard. Chemical shifts (ı) were reported relative to TMS, and
coupling constants (J) were reported in hertz (Hz). Mass spectra
were recorded on a Shimadzu QP 1100 EX mass spectrometer with
70-eV ionization potential. X-ray powder diffraction (XRD) was car-
ried out on a Philips X’Pert diffractometer with CuK␣ radiation. The
pore structure of the prepared catalyst was verified by the nitrogen
sorption isotherm ([5.0.0.3] Belsorp, BEL Japan, Inc.). Transmission
electron micrographs (TEM) were recorded on a Philips EM-208
instrument on an accelerating voltage of 100 kV. The morphology
of the catalyst and X-ray energy diffraction (XED) spectra were
recorded by scanning electron microscope model VEGA\\ TESCAN-
XMU instrument with an accelerating voltage of 20 kV.
3. Results and discussions
Scheme 2 indicates the process of incorporating l-prolinium
nitrate into the mesochannels of the (␣-Fe2O3)-MCM-41 material.
The prepared catalyst (␣-Fe2O3)-MCM-41-l-prolinium nitrate
was characterized with IR, XRD, SEM, TEM, XED, nitrogen
acid–base titration showed that the pH of the catalyst is 2.69.
In FT-IR spectra, the band in the region of 400–650 cm−1 is
attributed to the stretching vibrations of the (Fe O) bond in
␣-Fe2O3, and the band at about 1100 cm−1 belongs to (Si O)
2.1. Preparation of (Fe2O3)-MCM-41
A
mixture with molar ratio of 3.2 FeCl3:1.6 FeCl2:1
CTABr:39NH4OH:2300 H2O was used for the preparation of
naked Fe3O4 nanoparticles at room temperature. Typically, 2 g
of iron (III) chloride (FeCl3·6H2O) and 0.8 g of iron (II) chloride
(FeCl2·4H2O) were dissolved in 10 mL of distilled water under
N2 atmosphere. The resulting solution was added dropwise to
a 100 mL solution of 1.0 M NH4OH solution containing 0.4 g of
cetyltrimethylammonium bromide (CTABr) to construct a colloidal
suspension of iron oxide magnetic nanoparticles.
The broad and strong peak appeared at 2920–3388 cm−1 is
attributed to the stretching of OH and NH2+ bonds and strong peaks
at 1730 cm−1 and 1380 cm−1 are related to the C O stretching bond
of carboxyl group of ␣-amino acid nitrate salt (l-prolinium nitrate)
(Fig. 1b).
The magnetic MCM-41 was prepared by adding 20 mL of the
magnetic colloid to a 1 L solution with the molar ratio of 292
NH4OH:1 CTABr:2773 H2O under vigorous mixing and sonication.
The XRD pattern of the synthesized catalyst is presented in Fig. 2.
The XRD analysis was performed from 2.0◦ (2ꢀ) to 80.0◦ (2ꢀ). XRD
pattern in this region confirmed that the change of sample’s color