Sulfonated Honeycomb Coral (HC-SO3H): A new, green and highly efficient heterogeneous catalyst for the rapid one-pot pseudo-five component synthesis of 4,4′-(aryl methylene) bis(3-methyl-1H-pyrazol-5-ol)s

Article abstract of DOI:10.1007/s11696-016-0127-y

Sulfonated Honeycomb Coral (HC-SO₃H), has been synthesized from the reaction of Honeycomb Coral with chlorosulfonic acid as sulfonating agent. The as-synthesized catalyst was characterized via XRF, FT-IR, TGA, SEM-EDS, XRD, BET and pH analysis.

Full text of DOI:10.1007/s11696-016-0127-y

Chem. Pap.
DOI 10.1007/s11696-016-0127-y
ORIGINAL PAPER
Sulfonated Honeycomb Coral (HC-SO3H): a new, green
and highly efficient heterogeneous catalyst for the rapid one-pot
pseudo-five component synthesis of 4,40-(aryl methylene)
bis(3-methyl-1H-pyrazol-5-ol)s
Roya Jahanshahi1 Batool Akhlaghinia1
•
Received: 6 August 2016 / Accepted: 28 December 2016
Ó Institute of Chemistry, Slovak Academy of Sciences 2017
Abstract Sulfonated Honeycomb Coral (HC-SO3H), has
been synthesized from the reaction of Honeycomb Coral
with chlorosulfonic acid as sulfonating agent. The as-syn-
thesized catalyst was characterized via XRF, FT-IR, TGA,
SEM–EDS, XRD, BET and pH analysis. The superior
catalytic activity of HC-SO3H was investigated for the
synthesis of 4,40-(aryl methylene)bis(3-methyl-1H-pyrazol-
5-ol) derivatives through the one-pot pseudo-five compo-
nent reactions. The main advantages of this protocol
include simple procedure, excellent yields and short reac-
tion times besides the non-toxicity, high stability and
reusability of the catalyst.
Since catalysis organizes the basis of chemical industry
nowadays, the development of novel, eco-friendly, non-
toxic, inexpensive, stable, selective and recyclable cata-
lysts with improved efficiency has attracted a great deal of
interest, regarding to the green chemistry demands (Haile
et al. 2001; Shylesh et al. 2009; Dabral et al. 2014; Paga-
dala et al. 2014; Ahmed and Siddiqui 2014).
During the past decades, acid-catalyzed chemical pro-
cesses have been the subject of immense investigations,
with respect to the widespread applications in chemical
industries (Hosseini et al. 2016). However, although the
conventional homogeneous acid catalysts such as sulfuric
acid, hydrofluoric acid, hydrochloric acid and phosphoric
acid are commonly used in the large-scale production of
industrially important chemicals (Melero et al. 2006; Hara
Keywords Sulfonated Honeycomb Coral (HC-SO3H) Á
4,40-(Aryl methylene)bis(3-methyl-1H-pyrazol-5-ol)s Á
One-pot pseudo-five component reaction Á Heterogeneous
catalysis Á Green chemistry
´
et al. 2004; Gonzalez et al. 2012; Armstrong and Glover
1908), they suffer from several drawbacks. For instance,
these homogeneous acids are associated with corrosive
nature, high toxicity, hazardous handling and difficulty in
separation from the reaction products (Hosseini et al.
2016). These disadvantages lead to wasting energy, besides
the formation of immense amounts of waste products,
which are far from the concept of ‘‘Green Chemistry’’. In
this context, to overcome the problems caused by such
catalysts, heterogenization of these homogeneous catalysts
through their immobilization on various solid supports has
been developed (Parella et al. 2012; Siddiqui and Ahmed
2013; Zolfigol et al. 2013; Kuo et al. 2014; Mobaraki et al.
2014). This process leads to improve the aspects of envi-
ronmental compatibility, as well as economic, in numerous
industrial manufacturing.
Introduction
According to the ‘‘green and sustainable chemistry’’, one of
the most appealing developments in the synthetic organic
chemistry is applying the environmentally benign reagents
and reaction conditions (Anastas and Williamson 1998).
Electronic supplementary material The online version of this
article (doi:10.1007/s11696-016-0127-y) contains supplementary
material, which is available to authorized users.
& Batool Akhlaghinia
akhlaghinia@um.ac.ir
Sulfonation with chlorosulfonic acid has been received
considerable attention due to the suitable, convenient, fast
and efficient approach involved in the heterogenization
1
Department of Chemistry, Faculty of Sciences, Ferdowsi
University of Mashhad, P. O. Box 9177948974, Mashhad,
Iran
123

Chem. Pap.
process of the corresponding homogeneous catalysts
(Kolvari et al. 2015).
component condensation reactions in the presence of a
variety of catalyst such as pyridine trifluoroacetate
(Soleimani et al. 2012), 2-hydroxyethylammonium propi-
onate (2-HEAP) (Zhou and Zhang 2014), sulfonated rice
husk ash (RHA-SO3H) (Seddighi et al. 2013), N,2-di-
In recent years, multi-component reactions (MCRs)
have played crucial role in the combinatorial chemistry to
assemble complex target structures with attractive biolog-
ical aspects using simple and readily available starting
materials, through a one-pot process. The one-pot character
delivers fewer by-products, besides the lower costs, time
and energy involved, in comparison with classical stepwise
synthetic routes and leads to the formation of interesting
heterocyclic scaffolds (Zhu and Bienayme 2005).
bromo-6-chloro-3,4-dihydro-2H
benzo[e][1,2,4]thiadi-
azine-7-sulfonamide 1,1-dioxide (DCDBTSD) (Khazaei
et al. 2014), silica-bonded N-propylpiperazine sulfamic
acid (SBPPSA) (Tayebi and Niknam 2012), ultrasonic
irradiation (Hasaninejad et al. 2013) and sulfonated
nanohydroxyapatite functionalized with 2-aminoethyl
dihydrogen phosphate (HAP@AEPH2-SO3H) (Zarghani
and Akhlaghinia 2015a).
Synthesis of pyrazolone derivatives has attracted great
attention recently in synthetic organic chemistry due to
their therapeutic and pharmacological features (Elguero
1996). Among these significant class of heterocyclic
compounds, 4,40-(aryl methylene)bis(1H-pyrazol-5-ol)s
have numerous biological activities including anti-inflam-
matory (Sugiura et al. 1977), antinociceptive (Carlsson and
Jurna 1987), antipyretic (Behr et al. 1967), antidepressant
(Bailey et al. 1985), antimalarial (Acharya et al. 2010),
antitumor (Antre et al. 2012), antiviral (Sujatha et al. 2009)
and bactericidal (Mahajan et al. 1991) activities. In addi-
tion to these, 4,40-(aryl methylene)bis(1H-pyrazol-5-ol)s
are widely used as insecticides (Lecher 1955), pesticides
(Londershausen 1996), fungicides (Singh and Singh Singh
and Singh 1991), dyestuffs (Uzoukwu 1993), bis-Schiff
bases (Ren et al. 2012), ligands (Abbasi-Tarighat et al.
2013) and important intermediates in organic synthesis
(Hamama 2001). The most common route for the synthesis
of 4,40-(aryl methylene)bis(1H-pyrazol-5-ol)s is the one-
pot pseudo three-component reaction of aldehydes with the
initially formed 3-methyl-5-pyrazolone derivatives from
the condensation reaction of hydrazine/aryl hydrazine and
ethyl acetoacetate, in the presence of various catalytic
systems (Sujatha et al. 2009; Singh and Singh 1984; Wang
et al. 2005; Shi et al. 2005; Niknam et al. 2010; Hasa-
ninejad et al. 2011a, b; Elinson et al. 2008). However,
most of these synthetic approaches have restrictions
including the utilization of intense acidic or basic condi-
tions, toxic or expensive catalysts or reagents, lower yields
of the products and prolonged reaction times. Neverthe-
less, limited methods have been described for the synthesis
of these compounds through the one-pot pseudo-five
Considering the above points and as part of our continued
interest in the development of efficient and environmentally
benign heterogeneous catalysts (Zarghani and Akhlaghinia
2015a, b, 2016a, b; Razavi and Akhlaghinia 2015, 2016;
Ghodsinia and Akhlaghinia 2015; Zarei and Akhlaghinia
2015; Jahanshahi and Akhlaghinia 2015, 2016; Yousefi
Siavashi et al. 2016; Karimian et al. 2016; Ghodsinia et al.
2016), herein, we are willing to report a novel, green and
efficient heterogeneous catalyst which was prepared through
the immobilization of chlorosulfonic acid on Honeycomb
Coral (HC) as a new, sustainable, green and natural platform
(Scheme 1). The superior catalytic activity of sulfonated
Honeycomb Coral (HC-SO3H) was proved for the synthesis
of 4,40-(aryl methylene)-bis(3-methyl-1-phenyl-1H-pyrazol-
5-ol)s via a one-pot pseudo-five component condensation
reaction (see Scheme 2).
Experimental
All chemical reagents and solvents were purchased from
Merck and Sigma-Aldrich chemical companies and were
used as received without further purification. Honeycomb
Coral was obtained from the Persian Gulf in Iran. The purity
determinations of the products and the progress of the
reactions were accomplished by TLC on silica gel polygram
STL G/UV 254 plates. The melting points of the products
were determined with an Electrothermal Type 9100 melting
point apparatus. The FT-IR spectra were recorded on pres-
sed KBr pellets using an AVATAR 370 FT-IR spectrometer
OH
H
SO3
HO
OH
H
H
SO3
SO3
H
ClSO3
HO
H
SO3
OH
H
SO3
Coral
Coral
Honeycomb
(HC)
Honeycomb
(HC)
CH Cl
0
20 min
°C,
,
1) Dry
2)
2
30 min2
r.t.,
Sulfonated
Coral
Honeycomb
(HC-SO3H)
Scheme 1 Preparation of sulfonated Honeycomb Coral (HC-SO3H)
123

Chem. Pap.
Typical procedure for preparation of 4,40-(phenyl
methylene) bis(3-methyl-1 phenyl-1H-pyrazol-5-ol)
(Therma Nicolet spectrometer, USA) at room temperature in
the range between 4000 and 400 cm-1 with a resolution of
4 cm-1, and each spectrum was the average of 32 scans.
NMR spectra were recorded on an NMR Bruker Avance
spectrometer at 400 and 300 MHz in DMSO-d6 as solvent in
the presence of tetramethylsilane as internal standard and the
coupling constants (J values) are given in Hz. Elemental
analysis was performed using a Thermo Finnigan Flash EA
1112 Series instrument (furnace 900 °C, oven: 65 °C, flow
carrier 140 mL min-1, flow reference 100 mL min-1).
Mass spectra were recorded with a CH7A Varianmat Bre-
mem instrument at 70 eV electron impact ionization, in m/
z (rel %). The chemical compositions of the Honeycomb
Coral were specified with X-ray fluorescence spectroscopy
(XRF), using BRUKER axs-S4 EXPLORER spectrometer.
The crystal structure of the catalyst was analyzed by XRD
using a D8 ADVANCE-Bruker diffractometer operated at
A mixture of phenylhydrazine (2 mmol, 0.216 g), ethyl
acetoacetate (2 mmol, 0.260 g) and HC-SO3H (0.04 g) was
stirred at 70 °C for 1 min. Then, benzaldehyde (1 mmol,
0.106 g) was added to the reaction mixture. The reaction
was completed in less than 1 min, as monitored by TLC.
After that, hot ethanol (2 9 5 mL) was poured to the
reaction mixture and the mixture was stirred for additional
3 min. The resultant hot suspension was filtered off. The
filtrate was cooled to room temperature and the crude
product was precipitated. Thereafter, the crude product was
purified by recrystallization from ethanol (0.42 g, 98%). In
the following, to reuse the catalyst in the next runs, the
solid residue (HC-SO3H) was refluxed in EtOAc
(3 9 10 mL) for 15 min and centrifuged consecutively.
The recovered catalyst was then dried at 50 °C under
vacuum for 2 h and reused for several times without sig-
nificant loss of activity.
˚
40 kV and 30 mA, utilizing CuKa radiation (k = 0.154 A),
at a step size of 0.040° and step time of 1.5 s. The diffraction
angles (2h) were scanned from 10° to 80°. Elemental com-
positions were determined with a Leo 1450 VP scanning
electron microscope equipped with an SC7620 energy dis-
persive spectrometer (SEM–EDS) presenting a 133 eV res-
olution at 20 kV. Thermogravimetric analysis (TGA) was
carried out using a Shimadzu Thermogravimetric Analyzer
(TG-50) in the temperature range of 25–900 °C at a heating
rate of 10 °C min-1, under air atmosphere. Nitrogen
adsorption–desorption isotherms and BET analysis results
were obtained using a Belsorp mini II system at -196 °C
utilizing N2 as adsorbate. All yields refer to the isolated
products after purification by recrystallization.
Results and discussion
Corals are marine invertebrates of the class Anthozoa,
which are known as unique natural solids that can effi-
ciently catalyze organic reactions (Roschat et al. 2012;
Bigdeli et al. 2015), as well as have beneficial applications
in medical (Hamza et al. 2013). The principal components
of Corals are calcium carbonate (CaCO3) and also chitin
´
(Bennett et al. 2016; Juarez-de la Rosa et al. 2015). They
are mostly found in clear tropical oceans such as the Indian
Ocean, the Red Sea, the Gulf of Aden, the Persian Gulf, the
East China Sea and the West and Central Pacific Oceans.
The Coral species used in the present study is Honeycomb
Coral (Fig. 1).
Pre-preparation of Honeycomb Coral
To remove the probable contaminants trapped inside the
Honeycomb Coral structure, it was powdered thoroughly,
followed by washing with distilled water several times and
air-dried for 24 h.
Characterization of the catalyst
HC-SO3H as a novel potent and stable solid acid hetero-
geneous catalyst was synthesized according to Scheme 1.
The chemical composition of Honeycomb Coral was
determined by X-ray fluorescence analysis (XRF). Like-
wise, the structure and morphology of the newly synthe-
sized catalyst were fully characterized by different
techniques such as Fourier transform infrared (FT-IR)
spectroscopy, thermogravimetric (TGA) analysis, scanning
electron microscopy equipped with an energy dispersive
spectrometry (SEM–EDS), X-ray powder diffraction
(XRD), Brunauer, Emmett and Teller (BET) surface area
analysis and pH analysis. The results obtained from these
Preparation of sulfonated Honeycomb Coral (HC-
SO3H)
Chlorosulfonic acid 0.4 mL (6.5 mmol) was added
dropwise to a magnetically stirred mixture of Honey-
comb Coral (1 g) in dry dichloromethane (20 mL), in
an ice bath (0 °C). After a period of 20 min, the mix-
ture was stirred for an additional 30 min at room
temperature. Afterward, the suspension was filtered and
washed with dichloromethane (2 9 15 mL) and dried at
50 °C for 1 h to afford the HC-SO3H as a pale brown
powder.
123

Chem. Pap.
stretching vibration of the carbonate ion at about
1082 cm-1); m4 (for the asymmetric stretching vibrations
at about 1400–1500 cm-1).
In the case of the chitin segment of Honeycomb Coral, a
broad peak centered at 3421 cm-1 represented the com-
bined O–H and N–H stretching vibrations. Moreover, the
adsorption band centered at 2922 cm-1 was attributed to
the C–H stretching vibrations of CH2 and CH3 groups
(Rwei and Lien 2014). The indicative absorption bands
regarding to amide groups in the chitin structure are usually
observed at 1662 cm-1 (amide I), 1550 cm-1 (amide II)
and 1315 cm-1 (amide III) (Zarghani and Akhlaghinia
2016a). However, these absorption bands were covered by
broad and strong asymmetric stretching vibrations of
2-
CO3 ions (m4).
In the FT-IR spectrum of HC-SO3H (Fig. 2b), the
absorption bands at 593, 617 and 674 cm-1 can be
assigned to the asymmetric bending vibrations of sulfate
ions (Liu et al. 2009) that have been created as a result of
ion exchange during the sulfonation process. In the other
words, the appropriate exchange of carbonate ions with
sulfate ions has occurred.
Fig. 1 The Honeycomb Coral image
techniques, confirmed the successful preparation of the
new catalyst.
In addition, the FT-IR spectrum of HC-SO3H shows the
appearance of new absorption bands at about 1012, 1112,
1151 and 1174, which are attributed to the symmetric and
asymmetric stretching frequencies of S=O in the sulfonated
chitin. The spectrum also demonstrates a relatively broad
band at around 3200–3600 cm-1 due to the OH stretching
absorption of SO3H groups. Furthermore, the stretching
vibration band of C–N (related to the chitin groups), was
observed around 1470 cm-1 (Zarghani and Akhlaghinia
2016a). Besides, the other strong chitin band at 858 cm-1
(related to –CH3 in acetylamide groups) (Skołucka-Szary
et al. 2016; Ehrlich et al. 2007) can be evidently perceived
in Fig. 2b, c.
XRF analysis
The elemental composition analysis of Honeycomb Coral
was determined by XRF spectroscopy (see electronic
supplementary information). The obtained results showed
that the predominant composition of Honeycomb Coral is
CaO. Accordingly, the principal inorganic component of
Honeycomb Coral is considered to be a natural calcium
carbonate (CaCO3).
FT-IR spectroscopy
To evaluate the incorporation of sulfonic groups on the
Honeycomb Coral structure, FT-IR spectra of the
respective Honeycomb Coral and HC-SO3H have been
investigated (Fig. 2). As can be clearly inferred from
spectroscopic data, calcium carbonate and chitin are the
main Honeycomb Coral components (Bennett et al. 2016;
´
Juarez-de la Rosa et al. 2015). The FT-IR spectrum of
Honeycomb Coral, shown in Fig. 2a exhibits the charac-
teristic absorptions bands for aragonite phase (calcium
carbonate) in the Honeycomb Coral structure, which are
2-
related to the planar CO3 ions. There are four vibra-
tional modes in the free CO-3 2 ions (Plavsic et al. 1999),
which were established by the following absorption
bands: m1 (for the split in-plane bending vibrations at
about 711 cm-1); m2 (for the out-of-plane bending
absorption at about 852 cm-1); m3 (for the symmetric
Fig. 2 FT-IR spectrum of a Honeycomb Coral; b HC-SO3H and
c 7th recovered HC-SO3H
123

Chem. Pap.
Thermogravimetric analysis
titration of the catalyst. For this purpose, 100 mg of cata-
lyst was added to an aqueous solution of sodium hydroxide
(0.1 N, 15 mL). Then, the resulting mixture was stirred at
room temperature for 12 h. Finally, the leftover basic
solution was filtered and the filtrate was neutralized using a
standard solution of HCl (0.1 M). According to the con-
sumed volume of HCl (14.2 mL), the number of acidic
sites for HC-SO3H was found to be 0.80 mmol g-1. This
result was in a good agreement with those obtained from
TGA.
Thermogravimetric analysis (TGA) was performed to
evaluate the thermal stability of bare Honeycomb Coral
and the as-synthesized acidic catalyst (Fig. 3). As it is
evident in Fig. 3a, TGA thermogram of Honeycomb Coral
exhibited a weight loss of about 0.5% at temperatures
below 100 °C corresponding to the removal of physically
adsorbed water. The next weight loss of about 2.5% at
300 °C, is relating to the elimination of CO2 from the
Honeycomb Coral structure (Cuif et al. 2004). Also, the
simultaneous release of H2O in this temperature can be
explained either by the decomposition of hydrated chitin or
by water molecules strongly bound to the skeletal matrix
which cannot be released at lower temperatures (Cuif et al.
2004). The most prominent weight loss starting at
approximately 650 °C, is related to the decomposition of
CaCO3 to CaO (Cuif et al. 2004).
SEM–EDS analysis
Figure 4 depicts the scanning electron microscopy (SEM)
images of non-powdered Honeycomb Coral (Fig. 4a),
finely powdered Honeycomb Coral (Fig. 4b) and HC-
SO3H catalyst (Fig. 4c, d). Interestingly, SEM image of the
cross-sectional disc of non-powdered Honeycomb Coral
reveals a structure that looks like a honeycomb (Fig. 4a). In
comparing Fig. 4b with Fig. 4c, d, the surface morpho-
logical changes were clearly observed on the material due
to the modification process. In the other words, while the
finely powdered Honeycomb Coral has a smoothed mor-
phology (Fig. 4b), the surface of HC-SO3H is rough to a
certain extent. Accordingly, it can be concluded that the
functionalization procedure has been accomplished
successfully.
For HC-SO3H, it is clear that there are three steps of
weight loss (Fig. 3b). (1) Below 150 °C, the representative
mass loss is ascribed to the removal of physically adsorbed
water (about 3%). (2) Around 150–550 °C, a large weight
loss occurred, which can be predominantly attributed to
decomposition of SO3H groups (Naeimi and Mohamad-
abadi 2014) (about 9%). (3) Above 550 °C, the occurrence
of further mass losses at higher temperature resulted from
the decomposition of the Honeycomb Coral structure
(about 19%). According to the TGA thermogram, it can be
estimated that the amount of sulfonic acid groups delivered
Energy dispersive spectrum (EDS) of HC-SO3H
(Fig. 5) indicates the presence of Ca, S and O as the
main elements of HC-SO3H structure. Beside these, a
few other minerals were also found in low contents
(Cl, Na, Mg and Si). This analysis approves the suc-
cessful functionalization of the Honeycomb Coral (see
also XRF results in electronic supplementary
information).
to the Honeycomb Coral structure is about 0.82 mmol g-1
.
PH analysis
The total number concentrations of acidic sites of the HC-
SO3H were determined by acid–base back potentiometric
Fig. 3 TGA thermograms of
a Honeycomb Coral and b HC-
SO3H
123

Chem. Pap.
Fig. 4 SEM images of a cross-
sectional disc of a non-
powdered Honeycomb Coral;
b finely powdered Honeycomb
Coral and c, d HC-SO3H
Fig. 5 EDS analysis of HC-
SO3H
X-ray powder diffraction analysis
angles attributing to (1 0 4) and (1 1 3) crystallographic
faces, could be assigned to calcite (CaCO3) XRD diffrac-
tion peaks (JCPDS: 05-0586). However, XRD analysis of
HC-SO3H (Fig. 6b) revealed that CaCO3 with the
orthorhombic crystalline structure was converted to CaSO4
with preserving the orthorhombic crystalline structure
(JCPDS: 37-1496). The results confirm that although the
bona fide exchange of carbonate ions with sulfate ions has
occurred, the crystalline structure of catalyst was main-
tained, under the conditions used for the modification
process.
The crystallinity and phase identification of Honeycomb
Coral and HC-SO3H were determined using XRD. As
illustrated in Fig. 6a, the most intense diffraction peaks
appearing at angles corresponding to (1 1 1), (0 2 1), (0 1
2), (2 0 0), (1 1 2), (1 3 0), (2 1 1), (2 2 0), (2 2 1), (0 4 1),
(1 3 2), (1 1 3) and (2 3 1) reflections were in good
agreement with the standard pattern for crystalline arago-
nite (CaCO3) with orthorhombic structure (JCPDS:
05-0453). In addition, weak diffraction peaks appeared at
123

Chem. Pap.
Fig. 6 XRD patterns of
a Honeycomb Coral and b HC-
SO3H
BET analysis
catalyst which would promote the reactions that need an acidic
catalyst to speed-up. So, we have investigated the applicability
of HC-SO3H in developing the rapid one-pot pseudo-five
component synthesis of 4,40-(aryl methylene)-bis-(3-methyl-1-
phenyl-1Hpyrazol-5-ols) from phenylhydrazine/or hydrazine
hydrate, ethyl acetoacetate and aldehydes (Scheme 2).
The BET surface area measurement was conducted for
Honeycomb Coral (HC) and sulfonated Honeycomb Coral
(HC-SO3H) (see electronic supplementary information).
Table 1 illustrates the respective average surface area, pore
volume and mean pore diameter of both HC and HC-SO3H.
The BET surface area, pore volume and pore diameter of
HC are 120.25, 1.006 and 14.27, respectively. According to
the obtained data from Table 1, it can be concluded that the
introduction of sulfonic acid to the HC structure, shifted the
pore diameter to the smaller amounts and also decreased the
surface area and pore volume. These results confirm the
successful modification of HC with chlorosulfonic acid.
To find an appropriate reaction medium for the synthesis
of these compounds in the presence of the catalytic amount
of HC-SO3H, one-pot pseudo-five component reaction
between phenylhydrazine (2 mmol), ethyl acetoacetate
(2 mmol) and benzaldehyde (1 mmol) was selected as a
model reaction.
Various reaction conditions including different solvents,
temperatures and amount of the catalyst were examined and
the results are listed in Table 2. When the model reaction was
carried out in the absence of catalyst, either in solvent-free
condition or in H2O, at temperature ranging from 70 to 90 °C,
the progress of the reaction was sluggish, even after a long
reaction time (Table 2, entry 1–4). Interestingly, by applying
the model reaction at 70 °C, in the presence of 0.05 g of the
HC-SO3H, the desired product was obtained with excellent
yield, in less than 1 min (Table 2, entry 5). This result
denotes to the essential role of HC-SO3H in the synthesis of
4,40-(phenyl methylene)bis(3-methyl-1H-pyrazol-5-ol). Fur-
thermore, the results show that the lower the reaction tem-
perature, the less efficiently the reaction could proceed
(Table 2, entries 6–8). However, any further increase in the
temperature did not improve the reaction progress (Table 2,
entry 9). To determine the optimal amount of catalyst, we
have explored the model reaction at lower catalytic amounts
of HC-SO3H (0.04 and 0.03 g), under solvent-free conditions
Catalytic synthesis of 4,40-(aryl methylene) bis(3-
methyl-1H-pyrazol-5-ol)s
On the basis of the information obtained from the studies on the
natural Honeycomb Coral, we anticipated that this marine coral
can be used as an efficient and green platform for heteroge-
nization of sulfonic acid, to prepare a superlative solid acid
Table 1 Specific surface area (SBET), pore volume and mean pore
diameter of Honeycomb Coral (HC) and sulfonated Honeycomb
Coral (HC-SO3H)
Sample
SBET
(m2 g-1
Pore volume
(cm3 g-1
Mean pore
diameter (nm)
)
)
HC
120.25
90.38
1.006
0.504
14.27
12.67
HC-SO3H
123

Chem. Pap.
Scheme 2 One-pot pseudo-five
component synthesis of 4,40-
(aryl methylene)bis(3-methyl-1-
phenyl-1H-pyrazol-5-ol)s in the
presence of HC-SO3H
Table 2 Synthesis of 4,40-
(phenyl methylene)bis(3-
Entry
Catalyst (g)
Solvent
Temperature (°C)
Time (min)
Isolated yield (%)
methyl-1H-pyrazol-5-ol) in the
presence of HC-SO3H, under
different reaction conditions
1
–
Solvent-free
Solvent-free
H2O
70
90
70
90
70
60
40
r.t.
80
70
70
70
70
70
70
70
70
70
36 h
36 h
36 h
36 h
\1
10
15
15
15
15
98
90
65
40
98
98
94
78
72
68
25
15
79
15
2
–
3
–
4
–
H2O
5
0.05
0.05
0.05
0.05
0.05
0.04
0.03
0.04
0.04
0.04
0.04
0.04
0.04
0.04
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
H2O
6
7
20
8
4 h
\1
<1
9
10
11
12
13
14
15a
16b
17c
18d
a
10
15
EtOH
25
H2O/EtOH (1:1)
Solvent-free
Solvent-free
Solvent-free
Solvent-free
25
5 h
5 h
2 h
7 h
The reaction was performed in the presence of the thoroughly powdered Honeycomb Coral
The reaction was performed in the presence of the non-powdered Honeycomb Coral
The reaction was performed in the presence of the non-powdered sulfonated Honeycomb Coral
The reaction was performed in the presence of the CaCO3
b
c
d
at 70 °C (Table 2, entries 10, 11). The results revealed that
0.04 g of HC-SO3H was found to be the optimum amount of
catalyst in terms of yield and reaction time (Table 2, entry
10). Likewise, the reaction was carried out in solvents such as
H2O, EtOH and H2O/EtOH (1:1). The slow rate of such a
transformation in the presence of these solvents (maybe due
to the solvation effects), offered that the solvent-free condi-
tion is more appropriate to improve the reaction rate, in this
protocol (Table 2, entry 10). In another experiment, the
activity of the intact Honeycomb Coral both in the thoroughly
powdered form (as we have utilized it in our study) and also
the non-powdered form was tested for the same reaction
condition and only a scant yield of the product was obtained
(Table 2, entry 15, 16). To get more insight into the impact of
the structural form of the prime Honeycomb Coral on the
final catalyst activity, the sulfonation process was imple-
mented on the non-powdered form of the Honeycomb Coral
(exactly based on the mentioned procedure in the experi-
mental section) and next the model reaction was conducted in
the presence of the non-powdered HC-SO3H as catalyst. As it
is clear in Table 2, the results were far from satisfactory in
this context (Table 2, entry 17). These findings suggested that
123

Chem. Pap.
Table 3 Preparation of 4,40-(aryl methylene)bis(1H-pyrazol-5-ol)s catalyzed by HC-SO3H under solvent-free conditions at
70 °C
Entry R1
R2
Product Time (min) Isolated yield (%) M.p. (°C)
Found reported (references)
1
C6H5 C6H5
4a
4b
4c
4d
4e
4f
\1
\1
\1
18
5
98
98
97
84
82
95
83
83
96
96
92
97
95
95
87
91
83
93
90
95
88
95
94
89
173-174 171-172 (Hasaninejad et al. 2011a)
180–181 180–182 (Keshavarz and Vafaei-Nezhad 2016)
205–207 207–209 (Hasaninejad et al. 2011a)
235–237 236–237 (Hasaninejad et al. 2011a)
227–229 229–231 (Keshavarz and Vafaei-Nezhad 2016)
181–183 183–185 (Hasaninejad et al. 2011a)
148–149 150–151 (Zolfigol et al. 2015)
2
C6H5 4-FC6H4
3
C6H5 4-ClC6H4
C6H5 2-ClC6H4
C6H5 2,4-(Cl)2C6H3
C6H5 4-BrC6H4
C6H5 3-NO2C6H4
C6H5 2-NO2C6H4
C6H5 4-OHC6H4
C6H5 3-OHC6H4
C6H5 2-OHC6H4
C6H5 4-OMeC6H4
C6H5 3-OMeC6H4
C6H5 4-MeC6H4
C6H5 3-MeC6H4
4
5
6
\1
5
7
4g
4h
4i
8
8
219–221 222–224 (Zolfigol et al. 2015)
9
2
159–160 160–162 (Thummar et al. 2014)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
4j
3
166–167 165–168 (Niknam et al. 2010)
4k
4l
7
225–226 227–228 (Zolfigol et al. 2015)
\1
10
8
172–174 171–173 (Nader Ghaffari et al. 2016)
179–181 180–182 (Phatangare et al. 2012)
202–204 203–205 (Keshavarz and Vafaei-Nezhad 2016)
236–237 238–241 (Karimi-Jaberi et al. 2012)
265–267 266–268 (Baghernejad and Niknam 2012)
134-136 132-134 (Keshavarz and Vafaei-Nezhad 2016)
210–212 213–215 (Zolfigol et al. 2015)
4m
4n
4o
12
10
15
5
C6H5 5-Br-2-OHC6H3 4p
C6H5 4-iPrC6H4
C6H5 1-Naphthyl
C6H5 3-Pyridyl
C6H5 2-Pyridyl
4q
4r
4s
4t
7
238–239 238–240 (Niknam et al. 2013)
4
230–233 228–231 (Moosavi-Zare et al. 2013)
217–219 220–222 (Zarghani and Akhlaghinia 2015a)
231–233 228–230 (Nader Ghaffari et al. 2016)
223–225 224–226 (Nader Ghaffari et al. 2016)
197–199 202–204 (Nader Ghaffari et al. 2016)
C6H5 C6H5CH = CH2 4u
10
12
7
H
H
H
C6H5
4v
4w
4x
4-ClC6H4
4-MeC6H4
15
the sulfonation process was much better done for the thor-
oughly powdered Honeycomb Coral. This might be due to the
more available surface area and also porosity of the thor-
oughly powdered Honeycomb Coral (see BET analysis
results in Table 1), in comparison with the non-powdered
one, that improves the successful incorporation of the sulfonic
groups on its structure. In continuing our study, by consid-
ering calcium carbonate as the main inorganic component of
Honeycomb Coral (see XRF results in electronic supple-
mentary information), we decided to probe the reactivity of
CaCO3 as catalyst in this transformation. As demonstrated in
Table 2, the desired product was poorly obtained in the
presence of CaCO3 under solvent-free conditions at 70 °C
(Table 2, entry 18). These results confirm the superior cat-
alytic performance of the sulfonated Honeycomb Coral (HC-
SO3H), in this protocol. Afterward, in a separate experiment,
to compare the catalytic activity of HC-SO3H with its
homogenous counterparts, the model reaction was performed
under the optimized conditions in the presence of chlorosul-
fonic acid, p-toluene sulfonic acid and methane-sulfonic acid,
respectively. It was observed that the catalytic activity of
ClSO3H, PTSA and MeSO3H was very close to HC-SO3H
and the corresponding product was obtained in less than one
minute, in excellent isolated yield (98%). However, as pre-
viously mentioned, the main challenging problems in using
such catalysts are their homogeneous feature which leads to
difficult and expensive catalyst recovery process, along with
their corrosive nature that makes a troublesome handling.
Nevertheless, these problems have been eliminated in the HC-
SO3H as a new heterogeneous catalytic system.
Using the optimized reaction conditions, the activity of
HC-SO3H as catalyst was further confirmed in the green and
efficient preparation of 4,40-(aryl methylene)bis(1H-pyrazol-
5-ol)s (Table 3). For this purpose, phenyl hydrazine/or
123

Chem. Pap.
1
OH, C=N and C=C bonds, respectively. Moreover, the H
hydrazine (2 mmol) and ethyl acetoacetate (2 mmol) were
treated with a broad range of structurally diverse aromatic
aldehydes (1 mmol) in the presence of HC-SO3H to achieve
the intended products. This study showed that both electron
poor (Table 3, entries 2–8) and electron rich (Table 3, entries
9–18) aromatic aldehydes afforded the corresponding prod-
ucts rapidly, in excellent isolated yields. It is noteworthy that
heteroaromatic aldehydes such as pyridine carboxaldehydes
and allylic aldehydes such as cinnamaldehyde led to the
desired products, as well (Table 3, entries 19–21). Satisfac-
torily, we found that utilizing hydrazine instead of phenyl-
hydrazine in this transformation also resulted in the rapid
formation of the intended products, in high yields (Table 3,
entries 22–24).
NMR spectra displayed a sharp singlet resonating at around
5.50–4.89 ppm attributed to aryl methylene proton and also
two broad peaks around 13.91 and 12.40 ppm, that
revealed two –OH groups. Besides, the existence of a
signal at 32 ppm in 13C NMR spectra of the products, is
allocated to aryl methylene carbon. The elemental analysis
of the synthesized compounds was also in a very good
conformity with the presented structures. To more clarifi-
cation of the products structures, mass spectrometry was
carefully evaluated. As can be seen in the mass spectra,
molecular ion was not obvious in some cases which was
related to the very facile cleavage of C–C bond between
aryl methylene carbon and pyrazole ring. However, some
useful fragmentation information for each compound has
been found, which can be beneficial for the verification of
the desired products.
All of the synthesized products (4a–x) were known
compounds and their structures were confirmed by com-
parison of their melting points, FT-IR spectroscopy and 1H
NMR spectroscopy with those of authentic compounds.
Likewise, the selected compounds were further identified
by 13C NMR spectroscopy, mass spectrometry and ele-
mental analysis (see electronic supplementary informa-
tion). It is noteworthy that in the FT-IR spectrum of all
purified products the appearance of absorption bands at
about 3450–2500, 1600 and 1499 cm-1 was assigned to
By analogy with our investigation, a plausible mecha-
nism for the synthesis of 4,40-(phenyl methylene)bis(3-
methyl-1H-pyrazol-5-ol) derivatives in the presence of HC-
SO3H catalyst is proposed in Scheme 3.
According to this mechanism, the initial condensation
reaction between phenylhydrazine/hydrazine and proto-
nated form of ethyl acetoacetate (I), eventually leads to the
Scheme 3 Plausible
mechanism for the one-pot
pseudo-five component
synthesis of 4,40-(phenyl
methylene)bis(3-methyl-1H-
pyrazol-5-ol) using HC-SO3H
catalyst
123

Chem. Pap.
compounds and dried at 70 °C for 1 h. Next, the recovered
catalyst was reused in the consecutive runs, under the same
reaction conditions. The catalyst was successfully used in
seven subsequent reactions with undiminished efficiency
(Fig. 7). The average isolated yield of the product for seven
consecutive runs was 93.8%, which clearly proves the
outstanding practical reusability of the present catalyst.
According to the FT-IR spectrum of the 7th recovered
HC-SO3H (Fig. 2c), all of the characteristic peaks are well
preserved in terms of shape, position and relative intensity,
which is another evidence that demonstrates no substantial
changes occurred in the chemical structure of functional
groups and hydrogen bonding network of the catalyst.
The catalytic efficiency of HC-SO3H was compared
with the previously reported catalysts in literature that have
been employed for the one-pot pseudo-five component
preparation of 4,40-(phenyl methylene)bis(3-methyl-1H-
pyrazol-5-ol) and the related results are listed in Table 4.
Although, each of these methods has their own advantages,
but they often suffer from one or more of the following
drawbacks, such as higher temperatures (Zhou and Zhang
2014; Seddighi et al. 2013; Khazaei et al. 2014; Tayebi and
Niknam 2012; Zarghani and Akhlaghinia 2015a), certain
and difficult reaction conditions as ultrasonic irradiation
along with using organic solvent (Hasaninejad et al. 2013),
require longer reaction times to achieve reasonable yield of
the product (Zhou and Zhang 2014; Seddighi et al. 2013;
Khazaei et al. 2014; Tayebi and Niknam 2012; Hasaninejad
et al. 2013; Zarghani and Akhlaghinia 2015a) and most
importantly, the necessity of applying strict condition
(Zhou and Zhang 2014; Seddighi et al. 2013; Khazaei et al.
2014; Tayebi and Niknam 2012; Hasaninejad et al. 2013;
Zarghani and Akhlaghinia 2015a) and expensive precursors
(Zhou and Zhang 2014; Khazaei et al. 2014; Tayebi and
Niknam 2012; Hasaninejad et al. 2013; Zarghani and
Akhlaghinia 2015a) to prepare the corresponding catalysts.
Fig. 7 Synthesis of 4,40-(phenyl methylene)bis(3-methyl-1H-pyra-
zol-5-ol) in the presence of the reused HC-SO3H
formation of pyrazolone (IV), which is in equilibrium with
its tautomeric form (V). In the next step, the condensation
reaction between intermediate V and aldehyde in the acidic
condition, followed by dehydration, affords intermediate
VI. Thereupon, a Michael addition reaction between V and
VI happens to furnish the product VIII which undergoes a
tautomeric proton shift to deliver the desired product (IX).
Afterward, the released acidic catalyst re-enters the cat-
alytic cycle. It is assumed that the main catalytic perfor-
mance of catalyst was implemented through the sulfonated
active sites on the chitin matrix and the calcium sulfate
groups exciting in its inorganic matrix, as well. Further
studies to elucidate the details of the mechanism are
ongoing.
The reusability of the catalyst is a very important sub-
ject, particularly for commercial and industrial applica-
tions. Therefore, the recovery and reusability of HC-SO3H
were scrutinized for the synthesis of 4,40-(phenyl methy-
lene)bis(3-methyl-1H-pyrazol-5-ol), under the optimized
reaction conditions. Upon completion of the reaction, the
heterogeneous catalyst was easily separated from the
reaction mixture by vacuum filtration, followed by washing
with ethanol sequentially to remove the organic
Table 4 A comparative study regarding the catalytic efficiency of HC-SO3H and some previously reported catalytic systems, in the one-pot
pseudo-five component synthesis of 4,40-(phenyl methylene)bis(3-methyl-1H-pyrazol-5-ol)
Entry
Catalyst
Reaction conditions
Yield (%)
References
1
2
3
4
5
6
7
a
2-HEAPa
Solvent-free, 90 °C, 30 min
Solvent-free, 80 °C, 3 min
Solvent-free, 80 °C, 100 min
Solvent-free, 80 °C, 45 min
Ultrasonic irradiation, H2O/EtOH (1:1), r.t., 15 min
91
91
74
93
98
98
98
Zhou and Zhang (2014)
Seddighi et al. (2013)
Khazaei et al. (2014)
RHA-SO3H
DCDBTSDb
SBPPSAc
Tayebi and Niknam (2012)
Hasaninejad et al. (2013)
Zarghani and Akhlaghinia (2015a)
Present study
–
HAP@AEPH2-SO3Hd
Solvent-free, 80 °C, 3 min
Solvent-free, 70 °C, \1 min
HC-SO3H
2-Hydroxy ethylammonium propionate
b
c
d
N,2-Dibromo-6-chloro-3,4-dihydro-2H benzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide
Silica-bonded N-propylpiperazine sulfamic acid
Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate
123

Chem. Pap.
Armstrong HE, Glover WH (1908) Studies on Enzyme Action. XI.-
Hydrolysis of Raffinose by Acids and Enzymes. Proc R Soc
Lond Ser B 80:312–321
However, compared with these catalytic systems, the cur-
rent work shows unique advantages such as simplification
of the catalyst system and its synthesis and the application
of inexpensive natural, nontoxic and available precursor for
the preparation of a green and highly efficient heteroge-
neous catalyst with ease of handling, as well as the fast and
clean synthetic route and also the milder reaction
conditions.
Baghernejad M, Niknam
K
(2012) Synthesis of 4,40-(aryl-
methylene)bis(1H-pyrazol-5-ols) using silica-bonded ionic liq-
uid as recyclable catalyst. Int J Chem 4:52–60. doi:10.5539/ijc.
v4n3p52
Bailey DM, Hansen PE, Hlavac AG, Baizman ER, Pearl J, Defelice
AF, Feigenson ME (1985) 3,4-Diphenyl-1H-pyrazole-1-propa-
namine antidepressants. J Med Chem 28:256–260. doi:10.1021/
jm00380a020
Behr LC, Fusco R, Jarboe CH (1967) The chemistry of heterocyclic
compounds, pyrazoles, pyrazolines, pyrazolidines, indazoles and
condensed rings. In: Weissberger A (ed), vol 7. Interscience
Publishers, New York
Bennett JA, Wilson K, Lee AF (2016) Catalytic applications of waste
derived materials. J Mater Chem A 4:3617–3637. doi:10.1039/
C5TA09613H
Conclusions
In conclusion, we have introduced HC-SO3H as a novel,
green and highly powerful heterogeneous and recoverable
solid acid catalyst. The as-synthesized catalyst was fully
characterized by XRF, FT-IR, TGA, SEM–EDS, XRD and
pH analysis and then was utilized for simple, efficient and
rapid one-pot pseudo-five component synthesis of 4,40-
(aryl methylene)bis(1H-pyrazol-5-ol)s. The promising
features that have distinguished this approach from other
reported methods regarding this transformation are using
the highly efficient, green, inexpensive, easy handling and
recoverable catalyst, as well as simple reaction work-up,
which make the present methodology more economical and
industrially important. Furthermore, excellent yields, quick
reaction times and non-toxicity of the catalyst, besides the
solvent-free conditions are the other advantages that sup-
port the present method towards the green chemistry, as
well.
Bigdeli MR, Shushizadeh MR, Mohandespur B (2015) The Persian
Gulf Calcined Coral, Acropora species: an efficient catalyst for
aldol condensation. Jundishapur J Nat Pharmaceut Prod
10:26073–26078. doi:10.17795/jjnpp-26073
Carlsson KH, Jurna I (1987) The role of descending inhibition in the
antinociceptive effects of the pyrazolone derivatives, metamizol
(dipyrone) and aminophenazone (‘‘Pyramidon’’). Naunyn–Sch-
miedeberg’s Arch Pharmacol 335:154–159. doi:10.1007/
BF00177717
Cuif JP, Dauphin Y, Berthet P, Jegoudez J (2004) Associated water
and organic compounds in coral skeletons: quantitative thermo-
gravimetry coupled to infrared absorption spectrometry. Geo-
chem Geophys Geosyst 5:1–9. doi:10.1029/2004GC000783
Dabral S, Nishimura S, Ebitani K (2014) One-pot conversions of
raffinose into furfural derivatives and sugar alcohols by using
heterogeneous catalysts. ChemSusChem 7:260–267. doi:10.
1002/cssc.201300939
Ehrlich H, Krautter M, Hanke T, Simon P, Knieb C, Heinemann S,
Worch H (2007) First evidence of the presence of chitin in
skeletons of marine sponges. Part II. Glass sponges (Hexactinel-
lida: Porifera). J Exp Zool Part B 308:347–356. doi:10.1002/jez.
b.21174
Acknowledgements The authors gratefully acknowledge the partial
support of this study by Ferdowsi University of Mashhad Research
Council (Grant no. p/3/39490).
Elguero J (1996) Comprehensive heterocyclic chemistry II. In:
Katritzky AR, Rees CW, Scriven EFV (eds), vol 3. Pergamon
Press, Oxford
References
Elinson MN, Dorofeev AS, Nasybullin RF, Nikishin GI (2008) Facile
and convenient synthesis of 4,40-(arylmethylene)bis(1H-pyrazol-
5-ols) by electrocatalytic tandem Knoevenagel–Michael reac-
tion. Synthesis, 1933–1937. doi:10.1055/s-2008-1067079
Ghodsinia SSE, Akhlaghinia B (2015) A rapid metal free synthesis of
5-substituted-1H-tetrazoles using cuttlebone as a natural high
effective and low cost heterogeneous catalyst. RSC Adv
5:49849–49860. doi:10.1039/C5RA08147E
Ghodsinia SSE, Akhlaghinia B, Jahanshahi R (2016) Direct access to
stabilized CuI using cuttlebone as a natural-reducing support for
efficient CuAAC click reactions in water. RSC Adv
6:63613–63623. doi:10.1039/C6RA13314B
Abbasi-Tarighat M, Shahbazi E, Niknam K (2013) Simultaneous
determination of Mn2? and Fe3? as 4,40[(4-cholorophenyl)-
methylene] bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) complexes
in some foods, vegetable and water samples by artificial neural
networks. Food Chem 138:991–997
Acharya BN, Saraswat D, Tiwari M, Shrivastava AK, Ghorpade R,
Apna S, Kaushik MP (2010) Synthesis and antimalarial evalu-
ation of 1, 3, 5-trisubstituted pyrazolines. Eur J Med Chem
45:430–438. doi:10.1016/j.ejmech.2009.10.023
Ahmed N, Siddiqui ZN (2014) Sulphated silica tungstic acid as a
highly efficient and recyclable solid acid catalyst for the
synthesis of tetrahydropyrimidines and dihydropyrimidines.
J Mol Catal A Chem 387:45–56. doi:10.1016/j.molcata.2014.
02.019
Anastas PT, Williamson TC (1998) Green chemistry: frontiers in
benign chemical synthesis and process. Oxford University Press,
Oxford
´
Gonzalez MD, Cesteros Y, Llorca J, Salagre P (2012) Boosted
selectivity toward high glycerol tertiary butyl ethers by
microwave-assisted sulfonic acid-functionalization of SBA-15
and beta zeolite. J Catal 290:202–209. doi:10.1016/j.jcat.2012.
03.019
Haile SM, Boysen DA, Chisholm CRI, Merle RB (2001) Solid acids
as fuel cell electrolytes. Nature 410:910–913. doi:10.1038/
35073536
Hamama WS (2001) Pyrazolones as versatile precursors for the
synthesis of fused and binary heterocycles. Synth Commun
31:1335–1345. doi:10.1081/SCC-100104042
Antre RV, Cendilkumar A, Nagarajan R, Goli D, Oswal RJ (2012)
Synthesis, antitumor and antimicrobial activities of some novel
1-(substituted)-3-methyl-1H-pyrazol-5(4H)-one.
4:183–192. doi:10.3329/jsr.v4i1.7027
J
Sci Res
123

Chem. Pap.
Hamza S, Slimane N, Azari Z, Pluvinage G (2013) Structural and
mechanical properties of the coral and nacre and the potentiality
of their use as bone substitutes. Appl Surf Sci 264:485–491.
doi:10.1016/j.apsusc.2012.10.049
Kuo CH, Poyraz AS, Jin L, Meng Y, Pahalagedara L, Chen SY, Kriz
DA, Guild C, Gudz A, Suib SL (2014) Heterogeneous acidic TiO2
nanoparticles for efficient conversion of biomass derived carbo-
hydrates. Green Chem 16:785–791. doi:10.1039/C3GC40909K
Lecher HZ (1955) The chemistry of synthetic dyes and pigments.
J Am Chem Soc 77:6089. doi:10.1021/ja01627a110
Liu Y, Wang A, Freeman JJ (2009) 40th lunar and planetary science
conference. Washington University, Saint Louis, p 2128)
Londershausen M (1996) Review: approaches to new parasiticides.
Hara M, Yoshida T, Takagaki A, Takata T, Kondo JN, Hayashi S,
Domen K (2004) A carbon material as a strong protonic acid.
Angew Chem Int Ed 43:2955–2958. doi:10.1002/anie.200453947
Hasaninejad A, Shekouhy M, Zare A, Hoseini Ghattali SMS, Golzar
N (2011a) PEG-SO3H as a new, highly efficient and homoge-
neous polymeric catalyst for the synthesis of bis(in-
Pestic
Sci
48:269–292.
doi:10.1002/(SICI)1096-
dolyl)methanes
and
4,40-(arylmethylene)-bis(3-methyl-1-
9063(199612)48:4\269:AID-PS478[3.0.CO;2-B
Mahajan RN, Havaldar FH, Fernandes PS (1991) Syntheses and
phenyl-1Hpyrazol-5-ol)s in water. J Iran Chem Soc 8:411–423.
doi:10.1007/BF03249075
biological activity of heterocycles derived from 3-methoxy-i-
phenyl-ih-pyrazole-5-carboxylate.
68:245–246
Hasaninejad A, Zare A, Shekouhy M, Golzar N (2011b) Efficient
synthesis of 4,40-(arylmethylene)-bis(3-methyl-1-phenylpyrazol-
5-ol) derivatives in PEG-400 under catalyst-free conditions. Org
Prep Proced Int 43:131–137. doi:10.1080/00304948.2010.
526827
Hasaninejad A, Rasekhi Kazerooni M, Zare A (2013) Room-
temperature, catalyst-free, one-pot pseudo-five-component syn-
thesis of 4,4-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-
5-ol)s under ultrasonic irradiation. ACS Sustain Chem Eng
1:679–684. doi:10.1021/sc400081c
Hosseini MM, Kolvari E, Koukabi N, Ziyaei M, Zolfigol MA (2016)
Zirconia sulfuric acid: an efficient heterogeneous catalyst for the
one-pot synthesis of 3,4-dihydropyrimidinones under solvent-
free conditions. Catal Lett 146:1040–1049. doi:10.1007/s10562-
016-1723-8
J
Indian Chem Soc
Melero JA, van Grieken R, Morales G (2006) Advances in the
synthesis and catalytic applications of organosulfonic-function-
alized mesostructured materials. Chem Rev 106:3790–3812.
doi:10.1021/cr050994h
Mobaraki A, Movassagh B, Karimi B (2014) Hydrophobicity-
enhanced magnetic solid sulfonic acid: a simple approach to
improve the mass transfer of reaction partners on the surface of
the heterogeneous catalyst in water-generating reactions. Appl
Catal A 472:123–133. doi:10.1016/j.apcata.2013.12.018
Moosavi-Zare AR, Zolfigol MA, Zarei M, Zare A, Khakyzadeh V,
Hasaninejad A (2013) Design, characterization and application
of new ionic liquid 1-sulfopyridinium chloride as an efficient
catalyst for tandem Knoevenagel–Michael reaction of 3-methyl-
1-phenyl-1H-pyrazol-5(4H)-one with aldehydes. Appl Catal A
467:61–68. doi:10.1016/j.apcata.2013.07.004
Jahanshahi R, Akhlaghinia B (2015) Expanded perlite: an inexpensive
natural efficient heterogeneous catalyst for the green and highly
accelerated solvent-free synthesis of 5-substituted-1H-tetrazoles
using [bmim]N3 and nitriles. RSC Adv 5:104087–104094.
doi:10.1039/C5RA21481E
Nader Ghaffari K, Sharifah Bee Abd H, Salam JJ (2016) N-Methylim-
idazolium perchlorate as a new ionic liquid for the synthesis of
bis(pyrazol-5-ol)s under solvent-free conditions. Chin Chem Lett
27:104–108. doi:10.1016/j.cclet.2015.07.027
Jahanshahi R, Akhlaghinia B (2016) CuII immobilized on guanidi-
nated epibromohydrin functionalized c-Fe2O3@TiO2 (c-Fe2-
Naeimi H, Mohamadabadi S (2014) Sulfonic acid-functionalized
silica-coated magnetic nanoparticles as an efficient reusable
catalyst for the synthesis of 1-substituted 1H-tetrazoles under
solvent-free conditions. Dalton Trans 43:12967–12973. doi:10.
1039/C4DT01664E
Niknam K, Saberi D, Sadegheyan M, Deris A (2010) Silica-bonded S-
sulfonic acid: an efficient and recyclable solid acid catalyst for
the synthesis of 4,40-(arylmethylene)bis(1H-pyrazol-5-ols).
Tetrahedron Lett 51:692–694. doi:10.1016/j.tetlet.2009.11.114
Niknam K, Sadeghi Habibabad M, Deris A, Aeinjamshid N (2013)
Preparation of silica-bonded N-propyltriethylenetetramine as a
recyclable solid base catalyst for the synthesis of 4,40-(aryl-
methylene)bis(1H-pyrazol-5-ols). Monatsh Chem 144:987–992.
doi:10.1007/s00706-012-0910-6
Pagadala R, Maddila S, Dasireddy VDBC, Jonnalagadda SB (2014)
Zn-VCO3 hydrotalcite: a highly efficient and reusable heteroge-
neous catalyst for the Hantzsch dihydropyridine reaction. Catal
Commun 45:148–152. doi:10.1016/j.catcom.2013.11.012
Parella R, Naveen R, Babu SA (2012) Magnetic nano Fe3O4 and
CuFe2O4 as heterogeneous catalysts: a green method for the
stereo- and regioselective reactions of epoxides with indoles/
pyrroles. Catal Commun 29:118–121. doi:10.1016/j.catcom.
2012.09.030
O3@TiO2-EG-CuII):
a
novel magnetically recyclable
heterogeneous nanocatalyst for the green one-pot synthesis of
1,4-disubstituted 1,2,3-triazoles through alkyne–azide cycload-
dition in water. RSC Adv 6:29210–29219. doi:10.1039/
C6RA05468D
´
Juarez-de la Rosa BA, May-Crespo J, Quintana-Owen P, Gonzalez-
´
´
´
Gomez WS, Yan˜ez-Limon JM, Alvarado-Gil JJ (2015) Thermal
analysis and structural characterization of chitinous exoskeleton
from two marine invertebrates. Thermochim Acta 610:16–22.
doi:10.1016/j.tca.2015.04.015
Karimian E, Akhlaghinia B, Ghodsinia SSE (2016) An efficient and
convenient synthesis of N-substituted amides under heteroge-
neous condition using Al(HSO4)3 via Ritter reaction. J Chem Sci
128:429–439. doi:10.1007/s12039-016-1036-x
Karimi-Jaberi Z, Pooladian B, Moradi M, Ghasemi E (2012) 1,3,5-
tris(hydrogensulfato) benzene: a new and efficient catalyst for
synthesis of 4,40-(arylmethylene)bis(1H-pyrazol-5-ol) deriva-
tives. Chin J
2067(11)60477-4
Catal 33:1945–1949. doi:10.1016/S1872-
Keshavarz M, Vafaei-Nezhad M (2016) Design and characterization
of l-prolinate-amberlite as a novel heterogeneous organocatalyst
and its catalytic application in the synthesis of pyrazol-derivates.
Catal Lett 146:353–363. doi:10.1007/s10562-015-1668-3
Khazaei A, Abbasi F, Moosavi-Zare AR (2014) Tandem cyclocon-
densation-Knoevenagel–Michael reaction of phenyl hydrazine,
Phatangare KR, Padalkar VS, Gupta VD, Patil VS, Umape PG, Sekar
N (2012) Phosphomolybdic acid: an efficient and recyclable
solid acid catalyst for the synthesis of 4,40-(aryl-
acetoacetate derivatives and arylaldehydes.
38:5287–5292. doi:10.1039/C4NJ01079E
N
J
Chem
methylene)bis(1H-pyrazol-5-ols).
42:1349–1358. doi:10.1080/00397911.2010.539759
Synth
Commun
Kolvari E, Koukabi N, Hosseini MM (2015) Perlite: a cheap natural
support for immobilization of sulfonic acid as a heterogeneous solid
acid catalyst for the heterocyclic multicomponent reaction. J Mol
Catal A Chem 397:68–75. doi:10.1016/j.molcata.2014.10.026
Plavsic B, Kobe S, Orel B (1999) Identification of crystallization
forms of CaCO3 with FTIR spectroscopy. KZLTET 33:517–521
Razavi N, Akhlaghinia B (2015) Cu (II) immobilized on aminated
epichlorohydrin activated silica (CAES): as a new, green and
123

Chem. Pap.
efficient nanocatalyst for preparation of 5-substituted -1H-
RSC
Tayebi S, Niknam K (2012) Synthesis of 4,40-(arylmethylene)bis(1H-
pyrazol-5-ols) via multi-component reactions by using silica-
bonded sulfamic acid derivatives. Iran J Catal 2:69–74
Thummar BB, Tarpada UP, Raval DK (2014) Study on one-pot
biginelli-like synthesis of pyrazolo[3,4-d]pyrimidines in bron-
sted acidic ionic liquid under sonication and its mechanism.
J Heterocycl Chem 51:1740–1746. doi:10.1002/jhet.1870
Uzoukwu AB (1993) The synthesis and crystal structures of 1-phenyl-
3-methyl-4-butanolypyrazol-5-one and of two pyrazolonato
complexes of iron. Polyhedron 12:2719–2724. doi:10.1016/
S0277-5387(00)80123-0.Uzoukwu
Wang W, Wang SX, Qin XY, Li JT (2005) Reaction of aldehydes and
pyrazolones in the presence of sodium dodecyl sulfate in
aqueous media. Synth Commun 35:1263–1269. doi:10.1081/
SCC-200054854
Yousefi Siavashi N, Akhlaghinia B, Zarghani M (2016) Sulfonated
nanohydroxyapatite functionalized with 2-aminoethyl dihydro-
gen phosphate (HAP@AEPH2-SO3H) as a reusable solid acid for
direct esterification of carboxylic acids with alcohols. Res Chem
Intermed 42:5789–5806. doi:10.1007/s11164-015-2404-8
Zarei Z, Akhlaghinia B (2015) Ce(III) immobilised on aminated
epichlorohydrin-activated agarose matrix – ‘‘green’’ and efficient
catalyst for transamidation of carboxamides. Chem Pap
69:1421–1437. doi:10.1515/chempap-2015-0168
tetrazoles.
C4RA15148H
Adv
5:12372–12381.
doi:10.1039/
Razavi N, Akhlaghinia B (2016) Hydroxyapatite nanoparticles (HAP
NPs): a green and efficient heterogeneous catalyst for three-
component one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-
one derivatives in aqueous media. N J Chem 40:447–457. doi:10.
1039/C5NJ02123E
Ren T, Liu S, Li G, Zhang J, Guo J, Li W, Yang L (2012) Synthesis,
spectroscopic properties and theoretical studies of bis-Schiff
bases derived from polyamine and pyrazolones. Spectrochim
Acta Part A 97:167–175
Roschat W, Kacha M, Yoosuk B, Sudyoadsuk T, Promarak V (2012)
Biodiesel production based on heterogeneous process catalyzed
by solid waste coral fragment. Fuel 98:194–202. doi:10.1016/j.
fuel.2012.04.009
Rwei SP, Lien CC (2014) Synthesis and viscoelastic characterization
of sulfonated chitosan solutions. Colloid Polym Sci
292:785–795. doi:10.1007/s00396-013-3115-6
Seddighi M, Shirini F, Mamaghani M (2013) Sulfonated rice husk ash
(RHA-SO3H) as a highly efficient and reusable catalyst for the
synthesis of some bis-heterocyclic compounds. RSC Adv
3:24046–24053. doi:10.1039/C3RA44053B
Shi DQ, Chen J, Wu N, Zhuang QY, Wang XS (2005) Condensation
of aromatic aldehyde with 1-phenyl-3-methylpyrazol-5-one in
aqueous media. Chin J Organ Chem 25:405–408. http://sioc-
journal.cn/Jwk_yjhx/EN/abstract/abstract337595.shtml#
Shylesh S, Schweizer J, Demeshko S, Schu¨nemann V, Ernst S, Thiel
WR (2009) Nanoparticle supported, magnetically recoverable
oxodiperoxo molybdenum complexes: efficient catalysts for
Zarghani M, Akhlaghinia B (2015a) Sulfonated nanohydroxyapatite
functionalized with 2-aminoethyl dihydrogen phosphate
(HAP@AEPH2-SO3H) as a new recyclable and eco-friendly
catalyst for rapid one-pot synthesis of 4,40-(aryl methylene)bis(3-
methyl-1H-pyrazol-5-ol)s. RSC Adv 5:87769–87780. doi:10.
1039/c5ra16236j
selective
epoxidation
reactions.
Adv
351:1789–1795. doi:10.1002/adsc.200900416
Synth
Catal
Zarghani M, Akhlaghinia B (2015b) Copper immobilized on
aminated ferrite nanoparticles by 2-aminoethyl dihydrogen
phosphate (Fe3O4@AEPH2-CuII) catalyses the conversion of
aldoximes to nitriles. Appl Organomet Chem 29:683–689.
doi:10.1002/aoc.3351
Siddiqui ZN, Ahmed N (2013) NH2SO3H–SiO2 as a new water-
compatible, recyclable heterogeneous catalyst for the synthesis
of novel (a, b-unsaturated) b-amino ketones via aza-Michael
reaction. Appl Organomet Chem 27:553–561. doi:10.1002/aoc.
3031
Singh D, Singh D (1984) Syntheses of 1,3-disubstituted 4-aryli-
denepyrazolin-5-ones and the keto and enol forms of 4,40-
arylidenebis(1,3-disubstituted pyrazolin-5-ones). J Chem Eng
Data 29:355–356. doi:10.1021/je00037a040
Singh D, Singh D (1991) Synthesis and antifungal activity of some
4-arylmethylene derivatives of substituted pyrazolones. J Indian
Chem Soc 68:165–167
Skołucka-Szary K, Ramiega A, Piaskowska W, Janicki B, Grala M,
Rieske P, Bartczak Z, Piaskowski S (2016) Synthesis and
physicochemical characterization of chitin dihexanoate–A new
biocompatible chitin derivative–In comparison to chitin dibu-
tyrate. Mater Sci Eng C 60:489–502. doi:10.1016/j.msec.2015.
11.078
Soleimani E, Ghorbani S, Taran M, Sarvary A (2012) Synthesis of
4,40-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) derivatives
in water. C R Chim 15:955–961. doi:10.1016/j.crci.2012.07.003
Sugiura S, Ohno S, Ohtani O, Izumi K, Kitamikado T, Asai H, Kato
K, Hori M, Fujimura H (1977) Syntheses and antiinflammatory
and hypnotic activity of 5-alkoxy-3-(N-substituted carbamoyl)-
1-phenylpyrazoles. 4. J Med Chem 20:80–85. doi:10.1021/
jm00211a016
Sujatha K, Shanthi G, Selvam NP, Manoharan S, Perumal PT,
Rajendran M (2009) Synthesis and antiviral activity of 4,40-
(arylmethylene)bis(1H-pyrazol-5-ols) against peste des petits
ruminant virus (PPRV). Bioorg Med Chem Lett 19:4501–4503.
doi:10.1016/j.bmcl.2009.02.113
Zarghani M, Akhlaghinia B (2016a) Magnetically separable Fe3O4@-
chitin as an eco-friendly nanocatalyst with high efficiency for
green synthesis of 5-substituted-1H-tetrazoles under solvent-free
conditions.
C6RA07252F
RSC
Adv
6:31850–31860.
doi:10.1039/
Zarghani M, Akhlaghinia B (2016b) Green and efficient procedure for
Suzuki–Miyaura and Mizoroki–Heck coupling reactions using
palladium catalyst supported on phosphine functionalized ZrO2
NPs (ZrO2@ECP-Pd) as a new reusable nanocatalyst. Bull
Chem Soc Japan. doi:10.1246/bcsj.20160163
Zhou Z, Zhang Y (2014) An efficient and green one-pot three-
component synthesis of 4,40-(arylmethylene)bis(1H-pyrazol-5-
ol)s catalyzed by 2-hydroxy ethylammonium propionate. Green
Chem Lett Rev 7:18–23. doi:10.1080/17518253.2014.894142
Zhu J, Bienayme H (2005). Multicomponent reactions. In: Zhu J,
Bienayme H (eds), vol 3. Wiley-VCH, Weinheim
Zolfigol MA, Khazaei A, Safaiee M, Mokhlesi M, Rostamian R,
Bagheri M, Shiri M, Kruger HG (2013) Application of silica
vanadic acid as a heterogeneous, selective and highly reusable
catalyst for oxidation of sulfides at room temperature. J Mol
Catal A Chem 370:80–86. doi:10.1016/j.molcata.2012.12.015
Zolfigol MA, Ayazi-Nasrabadi R, Baghery S (2015) Synthesis and
characterization of two novel biological-based nano organo solid
acids with urea moiety and their catalytic applications in the
synthesis of 4,40-(arylmethylene)bis(1H-pyrazol-5-ol), cou-
marin-3-carboxylic acid and cinnamic acid derivatives under
mild and green conditions. RSC Adv 5:71942–71954. doi:10.
1039/C5RA14001C
123