Tungstophosphoric acid supported on highly organosoluble polyamide (PW 12/PA): Highly efficient catalysts for the synthesis of novel 1,3,5-triaryl-2-pyrazoline derivatives

Article abstract of DOI:10.1016/S1872-2067(10)60203-3

A novel compound constructed from polyoxometalate (H₃PW ₁₂O₄₀, PW₁₂) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method. A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound, PW₁₂/PA, in high yields. The structures of the compounds obtained were determined by IR and ¹H NMR spectra.

Full text of DOI:10.1016/S1872-2067(10)60203-3

CHINESE JOURNAL OF CATALYSIS
Volume 32, Issue 4, 2011
Online English edition of the Chinese language journal
Cite this article as: Chin. J. Catal., 2011, 32: 582–588.
RESEARCH PAPER
Tungstophosphoric Acid Supported on Highly Organosoluble
Polyamide (PW12/PA): Highly Efficient Catalysts for the
Synthesis of Novel 1,3,5-Triaryl-2-pyrazoline Derivatives
Razieh FAZAELI1,*, Hamid ALIYAN2, Shadpour MALLAKPOUR3,4, Zahra RAFIEE5,
Maryam BORDBAR6
1Department of Chemistry, Islamic Azad University, Shahreza Branch, 86145-311, Iran
2Islamic Azad University, Mobarakeh Branch, 84815-119, Iran
3Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111,
Iran
4Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111, Iran
5Department of Chemistry, Yasouj University, Yasouj 75914-353, Iran
6Department of Chemistry, Islamic Azad University, Qom Branch, Qom, Iran
Abstract: A novel compound constructed from polyoxometalate (H3PW12O40, PW12) and poly(amidoamine) (PA) was prepared at room
temperature in an aqueous solution by an impregnation method. A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by
the reaction between chalcone and phenylhydrazine in the presence of the title compound, PW12/PA, in high yields. The structures of the
compounds obtained were determined by IR and 1H NMR spectra.
Key words: inorganic-organic hybrid; polyoxometalate; pyrazoline; phenylhydrazine; chalcone
Pyrazolines are well known and important nitrogen-con-
taining five-membered heterocyclic compounds and various
methods have been used for their synthesis [1–4]. Pyrazoline
derivatives are attracting an increasing amount of interest by
many researchers in medicinal chemistry because of their
bioactivity such as antimicrobial [5,6], antiamoebic [7,8],
antinociceptive [9], anticancer [10], antidepressant [11], and
anti-inflammatory [12–16] activities, and also in conjugated
fluorescent dyes that emit blue fluorescence with high fluo-
rescence quantum yields [17,18] and electroluminescence
yields [19–21]. After the pioneering work of Fischer and
Knövenagel [22] in the late nineteenth century, the reactions of
Į,ȕ-unsaturated aldehydes and ketones with hydrazines be-
came one of the most popular methods for the preparation of
2-pyrazolines [23–30]. Among the various pyrazoline deriva-
tives, 1,3,5-triaryl-2-pyrazolines seem to be the most fre-
quently studied pyrazoline-type compounds. Several catalysts
have been developed for the preparation of these heterocycles
including a sodium acetate-acetic acid aqueous solution under
ultrasound irradiation [31], a hot acetic acid solution [32], a
K2CO3-mediated microwave irradiation [33], and H3PW12O40
[34].
In continuation of our previous work on the catalytic prop-
erties of heteropoly acids (HPAs) [35–37], we now report a
suitable synthesis of an inorganic-organic hybrid compound
constructed from polyoxometalate (H3PW12O40) and
poly(amidoamine) (PW12/PA) as a heterogeneous catalyst for
the synthesis of 1,3,5-triaryl-2-pyrazolines derivatives.
1 Experimental
All materials were commercial reagent grade. Aldehydes,
phenylhydrazine, and acetophenone were obtained from Merck
or Aldrich. H3PW12O40 was purchased from Merck. FT-IR
Received 23 November 2010. Accepted 9 January 2011.
*Corresponding author. Tel: +98-321-3232706-7; Fax: +98-321-3232701-2; E-mail: fazaeli@iaush.ac.ir
This work was supported by the Islamic Azad University, Shahreza Branch and the Research Affairs Division Isfahan University of Technology (IUT).
Copyright © 2011, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved.
DOI: 10.1016/S1872-2067(10)60203-3

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
spectra were obtained as potassium bromide pellets in the
method. The adsorption was performed following the proce-
1
range 400–4000 cm–1 with a Nicolet Impact 400 D. H NMR
dure described previously [40]. In a typical process, a 640 mg
portion of PW12 was dissolved in deionized water and im-
pregnated dropwise into 1600 mg of PA in 25 ml methanol with
constant agitation. The resulting pastes were dried for 4 h at
110 °C.
spectra were recorded with a Bruker Avance AQS 300 MHZ.
The melting points were determined using an electrothermal
digital melting point apparatus and are uncorrected. Reaction
courses and product mixtures were monitored by thin layer
chromatography (TLC).
1.2 Typical procedure for the synthesis of 1,3,5-triaryl-2-
pyrazoline
1.1 Preparation of the catalyst
1.1.1 Synthesis of support monomer
The starting chalcone 4 (Scheme 2) was easily prepared by
Claisen-Schmidt condensation between acetophenone and
aromatic aldehydes in the presence of an ethanolic solution of
sodium hydroxide according to a literature procedure [26].
The typical procedure for catalytic synthesis of
1,3,5-triaryl-2-pyrazoline was illustrated in Scheme 2. To a
reaction vessel was added chalcone (1 mmol), phenylhydrazine
(1 mmol), and PW12/PA (3 mol%). Reaction progress was
monitored by TLC. At the end of the reaction, the reaction
mixture was washed out of the vessel using CH2Cl2 (10 ml) and
then filtered. The supported catalyst was easily recovered
quantitatively by simple filtration. The filtrate was dried
(MgSO4) and evaporated. The crude product was purified on a
silica gel plate or a silica gel column (20% ethyl acetate in
hexane) to give 1,3,5-triaryl-2-pyrazoline. The products were
identified by a comparison of their physical data with those
prepared in accordance with the literature procedures.
5-[3-Phenyl-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-
dicarboximido)propanoyl-amino] isophthalic acid 1 was syn-
thesized and purified as described elsewhere [38].
1.1.2 Synthesis of polymer
The PAs were prepared by the following general procedure:
0.10 g (1.70 × 10ꢀ4 mol) of diacid monomer 1 and 0.0338 g
(1.70 × 10ꢀ4 mol) of diamine 2(Benzidine) were dissolved in
0.35 g of [1,3-(pr)2im]Br, and then 0.11 ml (4.26 × 10ꢀ4 mol) of
triphenyl phosphate (TPP) was added. The mixture was heated
at 110 °C for 2.5 h. As the reaction proceeded, the solution
became viscous. The resulting product was poured into 30 ml
of methanol, filtered, and dried under vacuum to give 0.120 g
(90%) of PA, 3 (Scheme 1) [39].
1.1.3 Preparation of PW12/PA
1.3 Selected spectroscopic data
The PW12/PA catalyst was prepared by the incipient wetness
5-(4-Methylphenyl)-1,3-diphenyl-2-pyrazoline (6c). 1H
O
C
O
C
H
H
N Ar N
[1,3-(pr)2im]Br
H2N Ar NH2
Diacid +
TPP
2
1
NH
C
O
H2
C
H
O
n
N
O
3
Scheme 1. Synthesis of polymer 3.
Ar1
Ph
O
PW12/PA
Ph
NH2
Ar2
+
N
H
N
Ar1
Ar2
EtOH
N
ꢀ
6a 6k
ꢀ
4a 4k
5
Scheme 2. Catalytic synthesis of 1,3,5-triaryl-2-pyrazoline derivatives (6) from chalcone and phenylhydrazine over PW12/PA.

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
NMR (CDCl3): G 2.34 (s, 3H, CH3), 3.14 (dd, J = 7.1, 17.0 Hz,
126.42, 127.91, 128.47, 128.89, 129.19, 130.56, 133.21,
135.03, 145.34, 147.17. IR (KBr, cm–1): Qmax 1120, 1261, 1512,
1597.
1H), 3.85 (dd, J = 12.1, 17.0 Hz, 1H), 5.27 (dd, J = 6.9, 12 Hz,
1H), 6.77–7.75 (m, 14H). Anal. calcd. for C22H20N2: C 84.62, H
6.41, N 8.97; Found: C: 84.61, H 6.43, N 9.00. 13C NMR
(CDCl3): G 21.68, 44.09, 64.73, 113.69, 119.47, 126.23,
128.43, 128.88, 129.34, 129.57, 130.19, 133.07, 137.67,
141.53, 145.43, 147.17. IR (KBr, cm–1): Qmax 1117, 1499, 1593.
5-(4-Chlorophenyl)-1,3-Diphenyl-2-Pyrazoline (6d). 1H-
NMR (CDCl3): G 3.04 (dd, J = 7.4, 17.6 Hz, 1H), 3.77 (dd, J =
11.6, 17.6 Hz, 1H), 5.67 (dd, J = 7.4, 11.6 Hz, 1H), 6.71–7.64
(m, 14H). Anal. Calcd. for C21H17ClN2: C 75.78, H 5.15, N
8.41; Found: C 75.69, H 5.10, N 8.49%. 13CNMR (CDCl3): G
43.4, 63.8, 113.4, 119.4, 125.7, 127.3, 128.5, 128.7, 128.9,
129.3, 129.9, 132.5, 133.3, 141.1, 144.6, 146.7. IR (KBr, cm–1):
3-(4-Chlorophenyl)-1,5-diphenyl-2-pyrazoline (6j). 1H
NMR (DMSO): G 3.15 (dd, J = 7.1, 17.0 Hz, 1H), 3.87 (dd, J =
12.2, 17.1 Hz, 1H), 5.33 (dd, J = 7.3, 12.4 Hz, 1H), 6.83–7.67
(m, 14H). Anal. calcd. for C21H17N2Cl: C 84.85, H 5.72, N
9.43; Found: C 84.81, H 5.77, N 9.47. 13C NMR (DMSO): G
42.39, 61.31, 113.53, 117.26, 126.83, 126.94, 128.64, 129.16,
129.39, 130.55, 132.17, 132.19, 136.05, 139.61, 143.73,
147.39. IR (KBr, cm–1): Qmax 1121, 1509, 1599.
2 Results and discussion
Q
max 1123, 1495, 1598.
2.1 Physicochemical characterization
5-(3-Chlorophenyl)-1,3-diphenyl-2-pyrazoline (6e). 1H
NMR (CDCl3): G 3.08 (dd, J = 6.8, 17.0 Hz, 1H), 3.43 (dd, J =
12.2, 17.2 Hz, 1H), 5.63 (dd, J = 6.9, 12.4 Hz, 1H), 6.85–7.81
(m, 14H). Anal. calcd. for C21H17N2Cl: C 85.85, H 5.72, N
9.43; Found: C 85.79, H 5.70, N 9.41. 13C NMR (CDCl3): G
42.37, 61.54, 113.58, 119.60, 124.44, 127.79, 128.07, 128.92,
129.18, 129.48, 130.67, 132.53, 133.04, 135.04, 139.67,
144.84, 147.53. IR (KBr, cm–1): Qmax 1127, 1501, 1593.
5-(2-Chlorophenyl)-1,3-diphenyl-2-pyrazoline (6f). 1H
NMR (CDCl3): G 3.06 (dd, J = 4.8, 17.6 Hz, 1H), 3.96 (dd, J =
11.2, 17.7 Hz, 1H), 5.64 (dd, J = 4.7, 11.0 Hz, 1H), 6.76–7.74
(m, 14H). Anal. Calcd. for C21H17ClN2: C 75.78, H 5.15, N
8.41; Found: C 75.83, H 5.23, N 8.38%. 13C NMR (CDCl3): G
41.9, 61.5, 113.3, 119.2, 125.9, 127.5, 127.9, 128.3, 128.5,
128.8, 129.3. 129.8, 131.4, 132.2, 139.5, 144.6, 147.4. IR
(KBr, cm–1): Qmax 1120, 1497, 1595.
Figure 1(a) shows the obtained XRD patterns of pure PA.
Peaks that correspond to an amorphous polymer are present.
Figure 1(b) shows the XRD pattern of a 35 wt% PW12 im-
pregnated PA that was dried at 110 °C. We observed that the
impregnated products are crystalline. Some peaks of PW12
overlapped with that of PA. This may result from the interac-
tion of PW12 with the support.
FT-IR is a powerful technique for the study of surface in-
teractions between HPA and organic or inorganic supports.
Figure 2(1) shows the FT-IR spectra of pure PA. The FT-IR
spectrum of the 35 wt% PW12/PA shows four bands in the range
1250–500 cmí1 (Fig. 2(2)). For the 110 °C dried samples,
(a)
1
5-(2,4-Dichlorophenyl)-1,3-diphenyl-2-pyrazoline (6g). H
NMR (CDCl3): G 3.02 (dd, J = 6.6, 17.6 Hz, 1H), 3.97 (dd, J =
12.5, 17.5 Hz, 1H), 5.59 (dd, J = 6.6, 12.2 Hz, 1H), 6.69–7.71
(m, 13H). Anal. Calcd. for C21H16Cl2N2: C 68.67, H 4.39, N
7.62; Found: C 68.73, H 4.39, N 7.71%. 13CNMR (CDCl3): G
41.5, 60.9, 113.5, 119.5, 124.3, 125.6, 127.4, 127.7, 128.6,
128.5, 128.5, 129.2, 129.5, 132.1, 133.9, 137.7, 144.4, 147.5.
IR (KBr, cm–1): Qmax 1118, 1503, 1589.
5-(3-Bromophenyl)-1,3-diphenyl-2-pyrazoline (6h). 1H
NMR (CDCl3): G 3.08 (dd, J = 7.1, 17.0 Hz, 1H), 3.35 (dd, J =
12.1, 16.9 Hz, 1H), 5.68 (dd, J = 6.9, 12.7 Hz, 1H), 6.80–7.75
(m, 14H). Anal. calcd. for C21H17N2Br: C 85.85, H 5.72, N
9.43; Found: C 85.78, H 5.69, N 9.43. 13C NMR (CDCl3): G
42.35, 60.47, 113.35, 119.50, 124.23, 127.94, 128.05, 129.06,
129.16, 129.35, 130.59, 132.41, 133.18, 139.66, 145.25,
147.14. IR (KBr, cm–1): Qmax 1126, 1502, 1598.
(b)
5-(4-Methoxyphenyl)-1,3-diphenyl-2-pyrazoline (6i). 1H
NMR (CDCl3): G 3.12 (dd, J = 7.1, 17.1 Hz, 1H), 3.82 (s, 3H,
OCH3), 3.87 (dd, J = 12.1, 16.9 Hz, 1H), 5.24 (dd, J = 7.2, 12
Hz, 1H), 6.75–7.85 (m, 14H). Anal. calcd. for C22H20N2O: C
84.62, H 6.41, N 8.97; Found: C 84.56, H 6.40, N 8.93. 13C
NMR (CDCl3): G 44.08, 55.64, 64.14, 113.72, 114.46, 119.54,
10
20
30
2T/(o )
40
50
60
Fig. 1. XRD patterns of PA (a) and PW12/PA (b).

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
the condensation of chalcone and phenylhydrazine in the
(1)
presence of a catalytic amount of PW12/PA was selected as a
model reaction.
To establish the optimal conditions, a series of experiments
was carried out by varying the amount of catalyst, the
stoichiometry of the reaction, and the temperature. Alcoholic
solvents (methanol and ethanol), CH2Cl2, CH3CN, and CHCl3
gave good conversions (Table 1, entries 1–4). Clearly, ethanol
stands out as the solvent of choice as it gave a fast conversion, a
high yield, and was easily removed. The effect of different
PW12 loading on the catalytic activity for the synthesis of the
1,3,5-triaryl-2-pyrazoline derivatives (after the catalyst was
dried at 150 °C) was investigated and the results are shown in
Table 1, entries 4–7. Hardly any reaction with PA occurred.
When PW12 was supported on PA, the catalytic activity in-
creased remarkably with an increase in the PW12 loading but
when the loading exceeded 35%, the catalytic activity de-
creased. The support does not always have a mere mechanical
role as it can also modify the catalytic properties of the deposit
and favor the growth of particular structures, and this includes
weak and strong interactions. The true role of the support in
this work is not clear but it appears that the nature of the sup-
port and the amount of deposit may influence the catalytic
properties of the supported catalysts [36]. These conditions
were applied to a series of substituted aromatic aldehydes.
(2)
4000 3500 3000 2500 2000 1500 1000 500
Wavenumber (cmꢀ1)
Fig. 2. FT-IR spectra of PA (1) and PW12/PA (2).
Keggin bands are observed at 1079, 979, 816, and 634 cmí1 for
PW12/PA.
2.2 Choice of reaction medium and the effect of the
catalyst and HPA loading on the synthesis of the
1,3,5-triaryl-2-pyrazolines derivatives
2.3 Synthesis of 1,3,5-triaryl-2-pyrazoline derivatives in
the presence of catalytic amounts of PW12/PA
The condensation reaction between chalcone and phenyl-
hydrazine was initially performed in the presence of a catalytic
amount of several supported polyoxometalates (Fig. 3). To
determine the most appropriate medium in this heterocycliza-
tion reaction, the synthesis of 1,3,5-triaryl-2-pyrazolines from
On the basis of the above results, we extended the scope and
generality of this method by cyclizing several structurally
diverse chalcones and phenylhydrazines to give 1,3,5-triaryl
pyrazoline using PW12/PA. The results are listed in Table 2.
The reactions proceeded well for all the substrates but those
100
PW12/KSF
PW12/ZrO2
90
Table 1 Effect of different conditions in the reaction of chalcone with
PW12/Al2O3
PW12/ TiO2
PW12/SiO2
PW12/PA
80
70
60
50
40
30
20
10
0
phenylhydrazine
Ph
Ph
O
PW12/PA
Ph
NH2
+
N
H
Ph
Ph
Ph
N
N
4a
5
6a
Entry
Solvent
MeOH
CH3CN
CH2Cl2
EtOH
PW12 loading (%)
Yielda (%)
1
2
3
4
5
6
7
8
25
25
25
25
30
35
40
35
56
60
38
87
90
95
95
70b
EtOH
0
2
4
6
8
10
EtOH
EtOH
Time (h)
EtOH
Fig. 3. Effect of the different supported-PW12 compounds in the reac-
tion of chalcone with phenylhydrazine. Reaction conditions: chalcone 1
mmol, phenylhydrazine 1 mmol, and supported-PW12 (2 mol%) in sol-
vent (5 ml) after 10 h at 45 °C.
Reaction conditions: chalcone 1 mmol, phenylhydrazine 1 mmol, and
PW12/PA (3 mol%) in solvent (5 ml) after 5 h at 45 °C.
aIsolated yield. br.t.

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
Table 2 Synthesis of 1,3,5-triaryl-2-pyrazoline derivatives in the presence of PW12/PA
Melting point (°C)
Product
Ar1
Ar2
Time (h)
Yielda (%)
TOF
Found
Reported
134–135 [33]
—
6a
6b
6c
6d
6e
6f
C6H5
C6H5
C6H5
3
> 98
90
1.09
0.72
1.33
0.58
0.91
0.67
0.58
0.77
1.64
0.77
0.55
132–134
137–139
129–131
132–134
130–132
132–134
128–130
139–141
110–112
141–143
143–145
4-NO2-C6H4
4-Me-C6H4
4-Cl-C6H4
3-Cl-C6H4
2-Cl-C6H4
2,4-Cl2-C6H4
3-Br-C6H4
4-MeO-C6H4
C6H5
4.25
2.75
5.25
3.5
4.5
5
C6H5
> 98
90
128–130 [31]
133–134 [32]
134–136 [31]
134–135 [32]
—
C6H5
C6H5
90
C6H5
87
6g
6h
6i
C6H5
87
C6H5
4
92
141–143 [31]
110–112 [31]
143–145 [31]
—
C6H5
2
> 98
92
6j
4-Cl-C6H4
4-Br-C6H4
4
6k
C6H5
5.5
90
Reaction conditions: chalcone 1 mmol, phenylhydrazine 1 mmol, and PW12/PA (3 mol%) in EtOH (5 ml) after 3 h at 45 °C.
aIsolated yield.
with electron-donating groups were generally more reactive
than those with electron-withdrawing groups.
2.4 Catalyst recovery
A reasonable pathway for the reaction between chalcone and
phenylhydrazine in the presence of PW12/PA is given in
Scheme 3.
The recovery and reusability of the PW12/PA catalyst was
also investigated. We noticed that after the addition of CH2Cl2
to the reaction mixture, these catalysts are easily recovered
quantitatively by simple filtration. The wet catalysts were
recycled (the nature of the recovered catalysts has previously
been determined by NAA, XRD, and FT-IR spectra) and no
appreciable change in activity was noticed after two cycles.
The obtained products were of the same purity as that in the
first and second runs, but the yields gradually decreased in the
runs carried out using the recycled catalyst. For example, the
We then attempted to prepare other types of 2-pyrazolines
using the above-mentioned optimum conditions. When alde-
hyde 7, methyl acetoacetate 8, and phenylhydrazine 5 (Scheme
4(a)) or acetyl acetonate 10 (1,3-diketone) and phenylhydra-
zine
5 (Scheme 4(b)) were used, the corresponding
2-pyrazolines (9, 11) were obtained in 87% or 82% yields,
respectively (Scheme 4).
[H2PW12O40]- /PA
+
OH
O
R1
R2
+ H3PW12O40/PA
R1
R2
..
Ph-NH-NH2
- H3PW12O40 /PA
Ph
..
Ph
HN
HN
+
HN
OH2
HN
OH
+ H3PW12O40 / PA
R1
R2
R1
R2
[H2PW12O40]-/PA
- H2O
- H3PW12O40/PA
R1
R1
R2
R2
N
N
N
N
H
Ph
Ph
Scheme 3. Suggested mechanism for the reaction of chalcone with phenylhydrazine in the presence of PW12/PA.

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
Ph
N
O
N
R
Ph
Ph
NH2
PA/PW12
EtOH
(a)
(b)
N
H
COOMe
+
+
RCHO
COOMe
5
7
8
9
O
O
NH2
PA/PW12
EtOH
N
H
+
N
Ph
N
H
5
10
11
Scheme 4. Preparation of other types of 2-pyrazolines in the presence of PW12/PA.
on a thermally stable and highly organosoluble polymer
Table
3
Recycling of 35% PW12/PA for the synthesis of the
(PW12/PA). This is an eco-friendly, inexpensive, and efficient
catalyst. The advantages of this catalytic system are mild re-
action conditions, short reaction times, high product yields,
easy catalyst preparation, non-toxicity of the catalysts, and
simple and clean work-up of the desired products. In addition,
the catalysts can be reused several times, although activity will
be reduced.
1,3,5-triaryl-2-pyrazoline derivatives
Run
1
Yielda (%)
98
95
67
43
2
3
4
Reaction conditions: chalcone (4a) 1 mmol, phenylhydrazine 1 mmol,
and PW12/PA (3 mol%) in EtOH (5 ml) after 3 h at 45 °C. The recovered
catalyst was washed with ethanol, dried at 100 °C for 6 h, and calcined at
400 °C for 3 h. aIsolated yield.
Acknowledgements
We gratefully thank the Islamic Azad University, Shahreza
Branch and the Research Affairs Division Isfahan University
of Technology (IUT) for financial support.
reaction between chalcone and phenylhydrazine with PW12/PA
afforded the corresponding 1,3,5-triaryl-2-pyrazoline in 98%,
95%, 67%, and 43% yields over four cycles in EtOH (Table 3).
HPA dissolves in polar media and, therefore, the leaching of
HPA from the HPA/support system was significant.
References
1
Wiley R H. In: Weissberger A Ed. The Chemistry of Heterocyclic
Compounds. Vol. 22. New York: Interscience Publishers, 1967.
180
2.5 Comparison between the catalytic activity of bulk
PW12 and supported PW12/PA
2
Elguero J. In: Katritzky A R, Rees C W, Scriven E F eds. Com-
prehensive Heterocyclic Chemistry II. Vol. 3. Oxford: Pergamon
Press, 1996.1
To show the effect of the polymer-support on the catalytic
activity of PW12 in the synthesis of the 1,3,5-triaryl-2-pyra-
zoline derivatives, we repeated all the reactions under the same
reaction conditions using the same amounts of catalyst and
substrates in EtOH. The obtained results show that the turnover
frequencies of the synthesis of the 1,3,5-triaryl-2-pyrazoline
derivatives catalyzed by PW12/PA were higher than that of
PW12. One explanation for this behavior is that bulk HPAs have
low specific structure areas (1–10 m2/g). It is important to
increase the surface area or, even better, increase the number of
accessible acid sites on the HPAs. This can be achieved by
dispersing the HPAs on a solid support with a high surface area
[35].
3
4
5
6
Lévai A. Khim Geterosikl Soedin, 1997: 747
Lévai A. J Heterocycl Chem, 2002, 39: 1
Manna K, Agrawal Y K. Bioorg Med Chem Lett, 2009, 19: 2688
Abdel-Wahab B F, Abdel-Aziz H A, Ahmed E M. Eur J Med
Chem, 2009, 44: 2632
7
8
9
Abid M, Bhat A R, Athar V, Azam A. Eur J Med Chem, 2009,
44: 417
Budakoti A, Bhat A R, Azam A. Eur J Med Chem, 2009, 44:
1317
Kaplancikli Z A, Turan-Zitouni G, Özdemir A, Can Ö D,
Chevallet P. Eur J Med Chem, 2009, 44: 2606
10 Havrylyuk D, Zimenkovsky B, Vasylenko O, Zaprutko L, Gzella
A, Lesyk R. Eur J Med Chem, 2009, 44: 1396
11 Gokhan-Kelekc N, Koyuno÷lu I S, Yabano÷lu S, Yelekçi K,
Özgen Ö, Uçar G, Erol K, Kendi E, Yeúilada A. Bioorg Med
Chem, 2009, 17: 675
3 Conclusions
We developed an alternative and simple procedure for the
synthesis of 1,3,5-triaryl pyrazoline using solid HPA supported
12 Barsoum F F, Hosni H M, Girgis A S. Bioorg Med Chem, 2006,
14: 3929

Razieh FAZAELI et al. / Chinese Journal of Catalysis, 2011, 32: 582–588
13 Amir M, Kumar H, Khan S A. Bioorg Med Chem Lett, 2008, 18:
26 Wiley R H, Jarboe C H, Hayes F N, Hansbury E, Nielsen J T,
Callahan P X, Sellars M C. J Org Chem, 1958, 23: 732
27 Sammour A E A. Tetrahedron, 1964, 20: 1067
28 Bhatnagar I, George M V. Tetrahedron, 1968, 24: 1293
29 Tóth G, SzöllĘsy Á, Lóránd T, Kónya T, Szabó D, Földesi A,
Lévai A. J Chem Soc, Perkin Trans 2, 1989: 319
918
14 Rathish I G, Javed K, Ahmad S, Bano S, Alam M S, Pillai K K,
Singh S, Bagchi V. Bioorg Med Chem Lett, 2009, 19: 255
15 Barsoum F F, Girgis A S. Eur J Med Chem, 2009, 44: 2172
16 Khode S, Maddi V, Aragade P, Palkar M, Ronad P K, Mamle-
desai S, Thippeswamy A H M, Satyanarayana D. Eur J Med
Chem, 2009, 44: 1682
30 SzöllĘsy Á, Tóth G, Lóránd T, Kónya T, Aradi F, Lévai A. J
Chem Soc, Perkin Trans 2. 1991: 489
17 Ji S J, Shi H B. Dyes Pigments, 2006, 70: 246
18 Bian B, Ji S J, Shi H B. Dyes Pigments, 2008, 76: 348
19 Wei X Q,Yang G, Cheng J B, Lu Z Y, Xie M G. Opt Mater, 2007,
29: 936
31 Li J T, Zhang X H, Lin Z P. Beilstein J Org Chem, 2007, 3: 13
32 Levai A. ARKIVOC, 2005, 2005(9): 344
33 Kidwai M, Kukreja S, Thakur R. Lett Org Chem, 2006, 3: 135
34 Fazaeli R, Aliyan H, Bordbar M, Mohammadi E. The Open
Catal J, 2010, 3: 79
20 Pramanik S, Banerjee P, Sarkar A, Mukherjee A, Mahalanabis K
K, Bhattacharya S C. Spectrochim Acta Part A, 2008, 71: 1327
21 Pokladko M, Gondek E, Sanetra J, Nizioá J, Danel A, Kityk I V,
Reshak A H. Spectrochim Acta Part A, 2009, 73: 281
22 Fischer E, Knövenagel O. Justus Liebigs Ann Chem, 1887, 2:
194
35 Fazaeli R, Tangestaninejad S, Aliyan H, Moghadam M. Appl
Catal A, 2006, 309: 44
36 Fazaeli R, Tangestaninejad S, Aliyan H. Appl Catal A, 2007,
318: 218
37 Fazaeli R, Aliyan H. Appl Catal A, 2007, 331: 78
38 Mallakpour S, Rafiee Z. React Funct Polym, 2009, 69: 252
39 Mallakpour S, Rafiee Z. Polym Adv Technol, 2010, 21: 817
40 Das D P, Parida K M. Appl Catal A, 2006, 305: 32
23 Raiford L C, Peterson W J. J Org Chem, 1937, 1: 544
24 Raiford L C, Gundy G V. J Org Chem, 1938, 3: 265
25 Raiford L C, Manley R H. J Org Chem, 1940, 5: 590