Synthesis, characterization and catalytic evaluation of BiCl 3-ZrO2 for the synthesis of novel pyrazolyl chalcones

Article abstract of DOI:10.1016/j.molcata.2014.07.016

BiCl₃-ZrO₂ as an efficient heterogeneous catalyst is prepared by a simple process and characterized by FT-IR, powder XRD, SEM-EDX, XRF and BET surface area analyses. Thermal stability of the catalyst has been examined by DSC-TG analyses. The catalyst is recyclable for several runs preserving its high activity. The catalytic activity of BiCl₃- ZrO₂ is explained by synthesizing a series of novel pyrazolyl chalcones in excellent yields.

Full text of DOI:10.1016/j.molcata.2014.07.016

Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
Contents lists available at ScienceDirect
Journal of Molecular Catalysis A: Chemical
journal homepage: www.elsevier.com/locate/molcata
Synthesis, characterization and catalytic evaluation of BiCl3-ZrO2 for
the synthesis of novel pyrazolyl chalcones
Saima Tarannum, Zeba N. Siddiqui∗
Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India
a r t i c l e i n f o
a b s t r a c t
Article history:
BiCl3-ZrO2 as an efficient heterogeneous catalyst is prepared by a simple process and characterized by
FT-IR, powder XRD, SEM-EDX, XRF and BET surface area analyses. Thermal stability of the catalyst has
been examined by DSC-TG analyses. The catalyst is recyclable for several runs preserving its high activity.
The catalytic activity of BiCl3-ZrO2 is explained by synthesizing a series of novel pyrazolyl chalcones in
excellent yields.
Received 16 March 2014
Received in revised form 5 July 2014
Accepted 11 July 2014
Available online 21 July 2014
© 2014 Elsevier B.V. All rights reserved.
Keywords:
BiCl3-ZrO2
Heterogeneous catalyst
Pyrazolyl chalcones
Solvent-free reaction.
1. Introduction
anticancer, antioxidant, antimicrobial, anti-inflammatory, antide-
pressant and anticonvulsant etc., [20–23] and also find applications
BiCl3 is an acid catalyst in homogeneous medium. A wide vari-
ety of reactions in homogeneous phase employing BiCl3 as efficient
catalyst is reported in literature [1–4]. Though there are numer-
ous advantages, the major drawbacks of BiCl3, as catalyst lie in its
low thermal stability, risks in handling, containment, disposal and
regeneration due to its toxic and corrosive nature, and difficulties
in separation from reaction mixture. Therefore, heterogenization of
BiCl3 with suitable catalyst support is an efficient way to find new
environmentally friendly catalyst with high catalytic potential [5].
It is pertinent to mention that heterogeneous catalysts are environ-
mentally benign, easily separable, reusable, and also exhibit high
catalytic activities towards different types of reactions [6–8]. More-
over, various heterogeneous catalysts used in Claisen-Schmidt
condensation for the synthesis of chalcones include sulfonic acid
functionalized mesoporous silicas [9], aminopropylated silica [10],
sulfated Degussa titania [11], natural phosphate [12], metal-
organic framework [13], NaNO3/hydroxyapatite [14], silica-H2SO4
[15], Mo10V2/SiO2 [16], calcined sodium nitrate/natural phosphate
[17], borontrifluoride-etherate [18], BF3·SiO2 [19] etc.
as dyestuffs, analytical reagents and applied as ligands for the
transition-metal-catalyzed cross-coupling reactions [24–26]. Link-
ing of pyrazole with a structurally diverse side chain containing
heterocyclic ring is an effective way to obtain heterocyclic deriva-
tives with high biological potential. In this context, pyrazolyl
chalcones find applications as antimicrobial, anti-inflammatory,
antioxidant and cytotoxic agents etc. [27,28]. Hence, an envi-
ronmentally benign methodology for the preparation of such
compounds is of great concern in synthetic organic chemistry.
In recent decades, zirconia has attracted much attention as a cat-
alyst support because of its high thermal and mechanical stability,
large surface area, amphoteric character and oxidizing-reducing
properties [29–31]. Thus, synthesis of zirconia based solid acids has
become an intellectual goal of researchers, due to its proven advan-
tages such as non-hazardous nature, improved surface properties,
enhanced catalytic activity and recyclability. Taking into consid-
eration the prospective use of zirconia as catalyst support and
BiCl3 as a reaction promoter herein, we wish to report an efficient
synthesis of zirconia supported BiCl3 at ambient temperature. The
structure, morphology and stability of the catalyst was established
with the help of FT-IR spectrum, powder x-ray diffraction (XRD),
scanning electron microscopy (SEM), energy dispersive x-ray
analysis (EDX), x-ray fluorescence (XRF), Brunauer–Emmett–Teller
(BET) surface area analysis, differential scanning calorimetry (DSC)
and thermo-gravimetric analysis (TGA). The catalytic activity of
the catalyst was explained by synthesizing pyrazolyl chalcones
via Claisen–Schmidt condensation involving energy sustainable
It is worth mentioning that substituted pyrazoles form an
exclusive class of heterocyclic compounds having remarkable
bioactivities such as anxiolytic, antihyperglycemic, analgesic,
∗
Corresponding author. Tel.: +91 9412653054.
E-mail addresses: siddiqui zeba@yahoo.co.in, zns.siddiqui@gmail.com
(Z.N. Siddiqui).
http://dx.doi.org/10.1016/j.molcata.2014.07.016
1381-1169/© 2014 Elsevier B.V. All rights reserved.

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
263
methodology. All pyrazolyl chalcones were identified on the basis
of spectral data (FT-IR, NMR and mass spectrometry).
CH3), 3.36 (s, 6H, 2 × NCH3), 6.96–8.27 (m, 10H, Ar-H), 8.27 (d, 1H,
J = 16.0 Hz, Hb), 8.32 (d, 1H, J = 15.6 Hz, Ha). 13C NMR (100 MHz): ı
14.36, 27.34, 115.29, 117.49, 121.96, 123.98, 127.62, 129.17, 130.07,
134.32, 136.66, 148.15, 149.29, 155.48, 176.23, 182.70. ESI-MS
(m/z) 459.14 (M+ + 1). Anal. Calcd (C25H22N4O5): C, 65.49; H, 4.83;
N, 12.22. Anal. Found (C25H22N4O5): C, 65.54; H, 4.88; N, 12.16.
2. Experimental
2.1. Chemicals and apparatus
5b
(2E)-3-(3-methyl-5-phenoxy-1-phenylpyrazol-4-yl)-1-
(2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Melting points of all synthesized compounds were taken in
a Riechert Thermover instrument and are uncorrected. The IR
spectra (KBr) were recorded on Perkin Elmer RXI spectrome-
ter. 1H NMR and 13C NMR spectra were recorded on a Bruker
DRX-300 and Bruker Avance II 400 spectrometer using tetram-
ethylsilane (TMS) as an internal standard and DMSO-d6/CDCl3
as solvent. ESI-MS was recorded on a Quattro II (ESI) spec-
Light yellow crystals; M.p: 260–265 ◦C. IR (KBr) (ꢁmax, cm−1):
1677 (C O), 1729 (C O), 3184 (NH). 1H NMR (DMSO-d6, 400 MHz):
ı 2.51 (s, 3H, CH3), 6.92–7.80 (m, 10H, Ar-H), 8.19 (d, 1H, J = 15.8 Hz,
Hb), 8.24 (d, 1H, J = 15.6 Hz, Ha), 11.28 (s, 2H, 2 × NH).13C NMR
(100 MHz): ı 13.67, 116.24, 121.36, 122.66, 122.88, 124.34, 127.90,
128.12, 131.24, 135.86, 139.18, 150.82, 154.64, 176.17, 187.49. ESI-
MS (m/z) 431.1 (M+ + 1). Anal. Calcd (C23H18N4O5): C, 64.18; H, 4.21;
N, 13.01. Anal. Found (C23H18N4O5): C, 64.13; H, 4.26; N, 13.07.
5c (2E)-3-(3-methyl-5-phenoxy-1-phenylpyrazol-4-yl)-1-(2-
mercapto-4,6-pyrimidinedione-5-yl)-2-propen-1-one
trometer. Elemental analyses (C,
H and N) were conducted
using the Elemental vario EL III elemental analyzer and their
results were found to be in agreement with the calculated
values. 5-chloro-3-methyl-1-phenylpyrazole-4-carbaldehyde and
5-aryloxy-3-methyl-1-phenylpyrazole-4-carbaldehyde were syn-
thesized by reported procedures [32,33]. Other chemicals were
of commercial grade and used without further purification. The
homogeneity of the compounds was checked by thin layer chro-
matography (TLC) on glass plates coated with silica gel G254 (E.
Merck) using chloroform-methanol (3:1) mixture as mobile phase
and visualized using iodine vapors. X-ray diffractograms (XRD) of
the catalyst were recorded in the 2ꢀ range of 10–80◦ with scan
rate of 4◦/min on a Rigaku Minifax X-ray diffractometer with Ni-
filtered Cu K␣ radiation at a wavelength of 1.54060 A◦. SEM-EDX
characterization of the catalyst was performed on a JEOL JSM-6510
scanning electron microscope equipped with energy dispersive x-
ray spectrometer operating at 20 kV. DSC data was obtained with
DSC-60 and TGA with DTG-60H (Simultaneous DTA-TG Apparatus),
Shimadzu instrument. X-ray fluorescence analysis was carried out
with a PHILLIPS PW 2404. BET surface area of the sample was mea-
sured from the nitrogen adsorption/desorption isotherms obtained
by using a Quantachrome Autosorb 1 C BET analyzer at 77 K tem-
perature. Prior to gas adsorption, the sample was degassed for 3 h
at 423 K.
Light yellow crystals; M.p: 280–285 ◦C. IR (KBr) (ꢁmax, cm−1):
1059 (C S), 1674 (C O), 1726 (C O), 3039 (NH). 1H NMR (DMSO-
d6, 400 MHz): ı 2.50 (s, 3H, CH3), 6.95–7.66 (m, 10H, Ar-H), 8.17 (d,
1H, J = 16.0 Hz, Ha), 8.17 (d, 1H, J = 16.0 Hz, Hb), 12.22 (s, 1H, NH),
12.73 (s, 1H, NH). 13C NMR (100 MHz): ı 13.96, 106.15, 116.09,
117.45, 121.97, 123.44, 128.64, 129.46, 130.57, 134.32, 137.40,
148.24, 150.24, 156.18, 177.04, 181.35. ESI-MS (m/z) 447.1 (M+ + 1).
Anal. Calcd (C23H18N4O4S): C, 61.87; H, 4.06; N, 12.54. Anal. Found
(C23H18N4O4S): C, 61.84; H, 4.12; N, 12.48.
5d (2E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-(3-
methyl-5-phenoxy-1-phenylpyrazol-4-yl)-2-propen-1-one
Light orange crystals; M.p: 180–185 ◦C. IR (KBr) (ꢁmax, cm−1):
1646 (C O), 1734 (C O), 3103 (OH). 1H NMR (DMSO-d6, 400 MHz):
ı 2.24 (s, 3H, CH3), 2.52 (s, 3H, CH3), 5.94 (s, 1H, CH), 7.25–7.58
(m, 10H, Ar-H), 7.88 (d, 1H, J = 16.0 Hz, Hb), 8.06 (d, 1H, J = 16.0 Hz,
Ha), 18.72 (s, 1H, OH). 13C NMR (100 MHz): ı 14.29, 24.45, 106.35,
115.29, 117.49, 123.98, 127.62, 130.07, 134.32, 136.66, 148.15,
154.72, 155.48, 160.24, 162.82, 176.28, 181.34. ESI-MS (m/z) 429.60
(M+ + 1). Anal. Calcd (C25H20N2O5): C, 70.08; H, 4.70; N, 6.53. Anal.
Found (C25H20N2O5): C, 70.01; H, 4.65; N, 6.55.
5e (2E)-1-(4-hydroxy-1-benzopyran-2-one-3-yl)-3-(3-methyl-
5-phenoxy-1-phenylpyrazol-4-yl)-2-propen-1-one
2.2. Preparation of catalyst (BiCl3-ZrO2)
Yellow crystals; M.p: 220–225 ◦C. IR (KBr) (ꢁmax, cm−1): 1648
(C O), 1731 (C O), 3074 (OH). 1H NMR (DMSO-d6, 400 MHz): ı 2.53
(s, 3H, CH3), 6.97–8.00 (m, 14H, Ar-H), 8.02 (d, 1H, J = 16.0 Hz, Ha),
8.10 (d, 1H, J = 15.9 Hz, Hb), 18.95 (s, 1H, OH). 13C NMR (100 MHz):
ı 13.36, 104.18, 106.26, 113.96, 115.29, 117.49, 123.98, 125.68,
128.82, 130.64, 134.76, 136.12, 148.28, 153.12, 155.52, 160.74,
162.20, 176.09, 182.12. ESI-MS (m/z) 465.47 (M+ + 1). Anal. Calcd
(C28H20N2O5): C, 72.40; H, 4.34; N, 6.03. Anal. Found (C28H20N2O5):
C, 72.32; H, 4.30; N, 6.07.
Zirconia (20 g) was activated by refluxing with HCl (6 M, 100 mL)
under stirring for 24 h. It was filtered, washed with double distilled
water and dried under vacuum at 70 ◦C for 24 h.
A mixture of activated zirconia (4.00 g) and bismuth (III) chlo-
ride (1.00 g) in toluene was stirred at room temperature overnight,
filtered off and washed with ethanol. The solid, as obtained was
dried at 120 ◦C under vacuum for 6 h as white powder.
2.3. General procedure for the preparation of products 5a–t
5f (2E)-3-(3-methyl-5-(4-nitrophenoxy)-1-phenylpyrazol-4-
yl)-1-(1,3-dimethyl-2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Yellow crystals; M.p: 225-230 ◦C. IR (KBr) (ꢁmax, cm−1): 1662
(C O), 1714 (C O). 1H NMR (DMSO-d6, 400 MHz): ı 2.51 (s, 3H,
CH3), 3.32 (s, 6H, 2 × NCH3), 7.23-7.86 (m, 9H, Ar-H), 8.23 (d, 1H,
J = 16.4 Hz, Hb), 8.53 (d, 1H, J = 16.2 Hz, Ha). 13C NMR (100 MHz): ı
14.22, 27.08, 117.14, 117.64, 121.34, 122.38, 126.42, 129.47, 131.79,
134.56, 137.04, 148.19, 149.63, 156.24, 175.64, 180.44. ESI-MS
(m/z) 504.1 (M+ + 1). Anal. Calcd (C25H21N5O7): C, 59.64; H, 4.20;
N, 13.91. Anal. Found (C25H21N5O7): C, 59.60; H, 4.27; N, 13.78.
5g (2E)-3-(3-methyl-5-(4-nitrophenoxy)-1-phenylpyrazol-4-
yl)-1-(2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
A
mixture of 5- aryloxy-3-methyl-1-phenylpyrazole-4-
carbaldehydes 3a-d (10 mmol), active methyl ketones 4a-e
(10 mmol), and 0.8 g of BiCl3-ZrO2 (20% w/w) was heated at 80 ◦C.
Upon completion of the reaction (as confirmed by TLC) the reaction
mixture was cooled to room temperature and ethyl acetate (5 mL)
was added. The reaction mixture was filtered to remove the
catalyst and filtrate concentrated to furnish products 5a-t which
was further purified by recrystallization with suitable solvents.
2.4. Spectroscopic Data
Yellow crystals; M.p: 220-225 ◦C. IR (KBr) (ꢁmax, cm−1): 1645
(C O), 1698 (C O), 3194 (NH). 1H NMR (DMSO-d6, 400 MHz): ı
2.48 (s, 3H, CH3), 6.88–7.92 (m, 9H, Ar-H), 8.12 (d, 1H, J = 16.0 Hz,
Hb), 8.20 (d, 1H, J = 16.2 Hz, Ha), 12.02 (s, 2H, 2 × NH).13C NMR
(100 MHz): ı 13.82, 116.14, 121.22, 122.60, 123.24, 123.41, 127.80,
5a (2E)-3-(3-methyl-5-phenoxy-1-phenylpyrazol-4-yl)-1-(1,3-
dimethyl-2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Yellow crystals; M.p: 185–190 ◦C. IR (KBr) (ꢁmax, cm−1): 1650
(C O), 1716 (C O). 1H NMR (DMSO-d6, 400 MHz): ı 2.52 (s, 3H,

264
S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
128.46, 129.49, 130.84, 136.06, 139.38, 149.32, 154.14, 175.74,
186.14. ESI-MS (m/z) 476.1 (M+ + 1). Anal. Calcd (C23H17N5O7): C,
58.10; H, 3.60; N, 14.73. Anal. Found (C23H17N5O7): C, 58.17; H,
3.69; N, 14.65.
(DMSO-d6, 400 MHz): ı 2.52 (s, 3H, CH3), 3.45 (s, 3H, O CH3),
6.85-7.96 (m, 9H, Ar-H), 8.08 (d, 1H, J = 15.8 Hz, Hb), 8.12
(d, 1H, J = 15.8 Hz, Ha), 11.36 (s, 1H, NH), 11.60 (s, 1H, NH).
13C NMR (100 MHz): ı 13.88, 54.10, 106.22, 116.24, 118.44,
121.12, 123.52, 127.69, 129.48, 130.37, 133.74, 137.92, 149.35,
150.41, 156.13, 177.26, 180.32. ESI-MS (m/z) 477.1 (M+ + 1). Anal.
Calcd (C24H20N4O5S): C, 60.49; H, 4.23; N, 11.75. Anal. Found
(C24H20N4O5S): C, 60.44; H, 4.28; N, 11.73.
5h (2E)-3-(3-methyl-5-(4-nitrophenoxy)-1-phenylpyrazol-4-
yl)-1-(2-mercapto-4,6-pyrimidinedione-5-yl)-2-propen-1-one
Yellow crystals; M.p: 235-240 ◦C. IR (KBr) (ꢁmax, cm−1): 1150
(C S), 1650 (C O), 1670 (C O), 3184 (NH). 1H NMR (DMSO-d6,
400 MHz): ı 2.52 (s, 3H, CH3), 6.85–7.86 (m, 9H, Ar-H), 8.32 (d,
1H, J = 15.8 Hz, Ha), 9.00 (d, 1H, J = 15.8 Hz, Hb), 11.46 (s, 1H, NH),
11.66 (s, 1H, NH). 13C NMR (100 MHz): ␦ 13.88, 106.22, 116.24,
118.44, 121.12, 123.52, 127.69, 129.48, 130.37, 133.74, 137.92,
149.35, 150.41, 156.13, 177.26, 180.32. ESI-MS (m/z) 492.1 (M+ + 1).
Anal. Calcd (C23H17N5O6S): C, 56.20; H, 3.48; N, 14.25. Anal. Found
(C23H17N5O6S): C, 56.26; H, 3.41; N, 14.20.
5n (2E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-(3-
methyl-5-(4-methoxyphenoxy)-1-phenylpyrazol-4-yl)-2-propen-
1-one
Light orange crystals; M.p: 210–215 ◦C. IR (KBr) (ꢁmax, cm−1):
1658 (C O), 1709 (C O), 3167 (OH). 1H NMR (DMSO-d6, 400 MHz):
ı 2.25 (s, 3H, CH3), 2.51 (s, 3H, CH3), 3.42 (s, 3H, OCH3), 5.95 (s, 1H,
CH), 7.24–7.76 (m, 9H, Ar-H), 7.96 (d, 1H, J = 15.6 Hz, Hb), 8.02 (d,
1H, J = 15.8 Hz, Ha), 18.14 (s, 1H, OH). 13C NMR (100 MHz): ı 14.34,
24.45, 53.18, 105.12, 115.64, 117.54, 123.12, 127.44, 130.72, 134.64,
135.86, 149.24, 154.72, 155.48, 156.92, 160.54, 163.74, 175.18,
180.90. ESI-MS (m/z) 459.64 (M+ + 1). Anal. Calcd (C26H22N2O6):
C, 68.11; H, 4.83; N, 6.11. Anal. Found (C26H22N2O6): C, 68.15; H,
4.88; N, 6.02.
5i
(2E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-(3-
methyl-5-(4-nitrophenoxy)-1-phenylpyrazol-4-yl)-2-propen-1-
one
Yellow crystals; M.p: 195–200 ◦C. IR (KBr) (ꢁmax, cm−1): 1644
(C O), 1698 (C O), 3194 (OH). 1H NMR (DMSO-d6, 400 MHz): ı 2.28
(s, 3H, CH3), 2.50 (s, 3H, CH3), 5.86 (s, 1H, CH), 6.98–7.64 (m, 9H,
Ar-H), 7.78 (d, 1H, J = 16.2 Hz, Hb), 8.00 (d, 1H, J = 15.8 Hz, Ha), 18.21
(s, 1H, OH). 13C NMR (100 MHz): ı 14.34, 23.88, 105.46, 116.84,
118.16, 123.20, 128.16, 132.72, 134.64, 136.82, 147.56, 149.47,
154.53, 155.48, 160.28, 162.74, 176.24, 181.92. ESI-MS (m/z) 474.43
(M+ + 1). Anal. Calcd (C25H19N3O7): C, 63.42; H, 4.04; N, 8.87. Anal.
Found (C25H19N3O7): C, 63.34; H, 4.09; N, 8.78.
5o (2E)-1-(4-hydroxy-1-benzopyran-2-one-3-yl)-3-(3-methyl-
5-(4-methoxyphenoxy)-1-phenylpyrazol-4-yl)-2-propen-1-one
Yellow crystals; M.p: 210–215 ◦C. IR (KBr) (ꢁmax, cm−1): 1634
(C O), 1718 (C O), 3134 (OH). 1H NMR (DMSO-d6, 400 MHz): ı
2.51 (s, 3H, CH3), 3.43 (s, 3H, OCH3), 6.97–8.02 (m, 13H, Ar-H), 8.02
(d, 1H, J = 16.0 Hz, Ha), 8.06 (d, 1H, J = 16.3 Hz, Hb), 18.92 (s, 1H,
OH). 13C NMR (100 MHz): ı 13.46, 53.04, 105.12, 106.16, 113.92,
115.17, 118.34, 124.64, 125.12, 128.18, 130.12, 130.32, 132.45,
134.46, 136.64, 148.72, 154.25, 156.46, 159.34, 160.62, 176.48,
180.60. ESI-MS (m/z) 495.82 (M+ + 1). Anal. Calcd (C29H22N2O6):
C, 70.43; H, 4.48; N, 5.66. Anal. Found (C29H22N2O6): C, 70.37; H,
4.41; N, 5.69.
5p (2E)-3-(3-methyl-5-(4-chlorophenoxy)-1-phenylpyrazol-4-
yl)-1-(1,3-dimethyl-2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Yellow crystals; M.p: 200-205 ◦C. IR (KBr) (ꢁmax, cm−1): 1662
(C O), 1714 (C O). 1H NMR (DMSO-d6, 400 MHz): ı 2.50 (s, 3H,
CH3), 3.20 (s, 6H, 2 × NCH3), 6.82-7.41 (m, 9H, Ar-H), 7.45 (d, 1H,
J = 15.8 Hz, Hb), 7.63 (d, 1H, J = 16.0 Hz, Ha). 13C NMR (100 MHz):
ı 14.12, 26.96, 116.24, 117.44, 121.66, 123.12, 126.62, 129.61,
130.07, 134.73, 135.68, 149.14, 149.20, 155.26, 176.68, 180.94. ESI-
MS (m/z) 493.1 (M+ + 1). Anal. Calcd (C25H21ClN4O5): C, 60.91; H,
4.29; N, 11.36. Anal. Found (C25H21ClN4O5): C, 60.97; H, 4.21; N,
11.28.
5j (2E)-1-(4-hydroxy-1-benzopyran-2-one-3-yl)-3-(3-methyl-
5-(4-nitrophenoxy)-1-phenylpyrazol-4-yl)-2-propen-1-one
Yellow crystals; M.p: 200–205 ◦C. IR (KBr) (ꢁmax, cm−1): 1639
(C O), 1666 (C O), 3115 (OH). 1H NMR (DMSO-d6, 400 MHz): ı
2.51 (s, 3H, CH3), 6.97–8.05 (m, 13H, Ar-H), 8.06 (d, 1H, J = 16.0 Hz,
Ha), 8.24 (d, 1H, J = 16.0 Hz, Hb), 18.88 (s, 1H, OH). 13C NMR
(100 MHz): ı 14.04, 104.23, 105.45, 113.82, 115.29, 118.63, 124.15,
126.44, 128.06, 128.14, 130.22, 132.80, 134.32, 136.72, 148.32,
153.30, 155.08, 159.82, 162.14, 175.26, 181.28. ESI-MS (m/z) 510.54
(M+ + 1). Anal. Calcd (C28H19N3O7): C, 66.01; H, 3.75; N, 8.24. Anal.
Found (C28H19N3O7): C, 66.10; H, 3.68; N, 8.21.
5k
(2E)-3-(3-methyl-5-(4-methoxyphenoxy)-1-phenylpyra-
zol-4-yl)-1-(1,3-dimethyl-2,4,6-pyrimidinetrione-5-yl)-2-
propen-1-one
Yellow crystals; M.p: 185–190 ◦C. IR (KBr) (ꢁmax, cm−1): 1650
(C O), 1714 (C O). 1H NMR (DMSO-d6, 400 MHz): ı 2.52 (s, 3H,
CH3), 3.15 (s, 6H, 2 × NCH3), 3.73 (s, 3H, OCH3), 6.83–7.35 (m,
9H, Ar-H), 7.47 (d, 1H, J = 15.8 Hz, Hb), 7.65 (d, 1H, J = 16.5 Hz,
Ha). 13C NMR (100 MHz): ı 13.88, 27.48, 54.04, 116.85, 118.65,
120.66, 122.14, 127.35, 129.63, 131.82, 132.96, 136.92, 148.43,
148.74, 156.06, 175.24, 181.34. ESI-MS (m/z) 489.1 (M+ + 1). Anal.
Calcd (C26H24N4O6): C, 63.92; H, 4.95; N, 11.46. Anal. Found
(C26H24N4O6): C, 63.96; H, 4.92; N, 11.42.
5q (2E)-3-(3-methyl-5-(4-chlorophenoxy)-1-phenylpyrazol-4-
yl)-1-(2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Light yellow crystals; M.p: 225-230 ◦C. IR (KBr) (ꢁmax, cm−1):
1645 (C O), 1700 (C O), 3103 (NH). 1H NMR (DMSO-d6, 400 MHz):
ı 2.49 (s, 3H, CH3), 6.92–7.86 (m, 9H, Ar-H), 8.00 (d, 1H, J = 15.6 Hz,
Hb), 8.05 (d, 1H, J = 16.0 Hz, Ha), 11.64 (s, 2H, 2 × NH).13C NMR
(100 MHz): ı 14.04, 117.25, 121.02, 122.14, 123.31, 127.82, 128.46,
129.24, 130.84, 136.02, 139.35, 149.40, 150.32, 154.56, 174.92,
185.12. ESI-MS (m/z) 465.1 (M+ + 1). Anal. Calcd (C23H17ClN4O5):
C, 59.42; H, 3.68; N, 12.05. Anal. Found (C23H17ClN4O5): C, 59.47;
H, 3.62; N, 12.12.
5l (2E)-3-(3-methyl-5-(4-methoxyphenoxy)-1-phenylpyrazol-
4-yl)-1-(2,4,6-pyrimidinetrione-5-yl)-2-propen-1-one
Light yellow crystals; M.p: 220–225 ◦C. IR (KBr) (ꢁmax, cm−1):
1662 (C O), 1715 (C O), 3146 (NH). 1H NMR (DMSO-d6, 400 MHz):
ı 2.50 (s, 3H, CH3), 3.56 (s, 3H, OCH3), 6.98–8.02 (m, 9H, Ar-H),
8.02 (d, 1H, J = 15.8 Hz, Ha), 8.08 (d, 1H, J = 15.6 Hz, Hb), 11.74 (s,
2H, 2 × NH). 13C NMR (100 MHz): ı 13.62, 53.68, 116.14, 121.25,
122.76, 124.38, 127.12, 128.37, 129.52, 131.04, 136.46, 138.12,
148.32, 151.54, 154.40, 173.14, 184.28. ESI-MS (m/z) 461.1 (M+ + 1).
Anal. Calcd (C24H20N4O6): C, 62.60; H, 4.37; N, 12.16. Anal. Found
(C24H20N4O6): C, 62.64; H, 4.27; N, 12.11.
5r (2E)-3-(3-methyl-5-(4-chlorophenoxy)-1-phenylpyrazol-4-
yl)-1-(2-mercapto-4,6-pyrimidinedione-5-yl)-2-propen-1-one
Light yellow crystals; M.p: 240–245 ◦C. IR (KBr) (ꢁmax, cm−1):
1087 (C S), 1662 (C O), 1700 (C O), 3108 (NH). 1H NMR (DMSO-
d6, 400 MHz): ı 2.56 (s, 3H, CH3), 7.45–8.02 (m, 9H, Ar-H), 8.06 (d,
1H, J = 15.8 Hz, Hb), 8.10 (d, 1H, J = 15.7 Hz, Ha), 11.46 (s, 1H, NH),
11.72 (s, 1H, NH). 13C NMR (100 MHz): ␦ 14.04, 105.89, 116.64,
117.74, 121.68, 122.72, 127.39, 128.18, 131.06, 133.26, 138.14,
151.26, 157.32, 176.20, 182.06. ESI-MS (m/z) 481.1 (M+ + 1). Anal.
Calcd (C23H17ClN4O4S): C, 57.44; H, 3.56; N, 11.65. Anal. Found
(C23H17ClN4O4S): C, 57.42; H, 3.48; N, 11.59.
5 m (2E)-3-(3-methyl-5-(4-methoxyphenoxy)-1-phenylpyra-
zol-4-yl)-1-(2-mercapto-4,6-pyrimidinedione-5-yl)-2-propen-1-
one
Light yellow crystals; M.p: 230–235 ◦C. IR (KBr) (ꢁmax, cm−1):
1007 (C S), 1678 (C O), 1714 (C O), 3126 (NH). 1H NMR

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
265
Fig. 1. FT-IR Spectra of (a) ZrO2, (b) BiCl3 and (c) BiCl3-ZrO2.
Scheme 1. Synthesis of catalyst BiCl3-ZrO2.
3.1.1. FT-IR spectrum of BiCl3-ZrO2
The FT-IR spectrum of ZrO2 (Fig. 1a) showeda broad asymmetric
stretching band in the region of 3429 cm−1 due to OH-group. Weak
5s (2E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-(3-
methyl-5-(4-chlorophenoxy)-1-phenylpyrazol-4-yl)-2-propen-1-
one
bands at 1641 and 1391 cm−1 were due to (H
O
H) bending and
O) bending vibrations. A weak bending band at 591 cm−1
was attributed to Zr H bond. In spectrum of BiCl3 (Fig. 1b),
(O
H
Light orange crystals; M.p: 180-185 ◦C. IR (KBr) (ꢁmax, cm−1):
1632 (C O), 1688 (C O), 3182 (OH). 1H NMR (DMSO-d6, 400 MHz):
2.26 (s, 3H, CH3), 2.50 (s, 3H, CH3), 5.94 (s, 1H, CH), 7.14–7.64
(m, 9H, Ar-H), 7. 88 (d, 1H, J = 15.6 Hz, Hb), 7.90 (d, 1H, J = 15.8 Hz,
Ha), 18.36 (s, 1H, OH). 13C NMR (100 MHz): ı 13.86, 22.10, 104.64,
116.72, 118.14, 124.04, 127.28, 130.28, 135.12, 136.84, 148.26,
154.16, 155.92, 160.74, 162.46, 175.56, 180.46. ESI-MS (m/z) 463.32
(M+ + 1). Anal. Calcd (C25H19ClN2O5): C, 64.86; H, 4.13; N, 6.05. Anal.
Found (C25H19ClN2O5): C, 64.81; H, 4.18; N, 6.13.
O
absorption peaks at 1600 and 1008 cm−1 indicated the asymmet-
ric and symmetric stretching vibrations of Bi Cl bond. A sharper
absorption band of OH-group at 3545 cm−1 in BiCl3 was appeared
due to its strong hygroscopic property. The FT-IR spectrum of cat-
alyst (Fig. 1c) showed peaks corresponding to both ZrO2 and BiCl3.
A broad band in the region of 3436 cm−1 was assigned to ( OH)
stretching vibration, whereas bands at 1632 and 1058 cm−1 were
due to asymmetric and symmetric stretching vibrations of Bi Cl
respectively. A broad absorption band at 593 cm−1 was attributed
5t (2E)-1-(4-hydroxy-1-benzopyran-2-one-3-yl)-3-(3-methyl-
5-(4-chlorophenoxy)-1-phenylpyrazol-4-yl)-2-propen-1-one
Yellow crystals; M.p: 190-195 ◦C. IR (KBr) (ꢁmax, cm−1): 1620
(C O), 1712 (C O), 3125 (OH). 1H NMR (DMSO-d6, 400 MHz): ı
2.51 (s, 3H, CH3), 6.97-7.77 (m, 13H, Ar-H), 8.00 (d, 1H, J = 16.0 Hz,
Ha), 8.08 (d, 1H, J = 15.9 Hz, Hb), 18.95 (s, 1H, OH). 13C NMR
(100 MHz): ı 14.36, 104.56, 105.68, 114.26, 115.72, 118.26, 125.05,
126.92, 128.62, 129.24, 131.76, 132.14, 134.18, 136.45, 148.74,
154.26, 155.59, 159.17, 162.34, 175.19, 182.16. ESI-MS (m/z) 499.74
(M+ + 1). Anal. Calcd (C28H19ClN2O5): C, 67.40; H, 3.83; N, 5.61. Anal.
Found (C28H19ClN2O5): C, 67.32; H, 3.76; N, 5.65.
to bending vibration of Zr
O Bi bond.
3.1.2. Powder x-ray diffraction (XRD) analysis of BiCl3-ZrO2
The XRD patterns of the support and supported catalyst showed
crystallinity and sharper peaks. XRD pattern of pure zirconia
(Fig. 2a) can be described as the sum of the monoclinic and tetrago-
nal phases of zirconia. It is an established fact that ZrO2-tetragonal
phase is more active in catalysis [34]. For BiCl3-ZrO2, new peaks
appeared in the region of 10–30◦ showed that tetragonal phase
becoming dominant for zirconia supported with BiCl3 (Fig. 2b).
3. Results and discussion
3.1.3. SEM-EDX analysis of the catalyst
For the morphology of catalyst, SEM image of 20% BiCl3-ZrO2
(Fig. 3a and b) showed non-uniform distribution of the particles
with agglomerates.
EDX analysis of the catalyst revealed peaks for Bi, Cl, Zr and O
indicating formation of the expected catalytic system (Fig. 4).
3.1. Catalyst synthesis and characterization
BiCl3-ZrO2 was prepared by stirring BiCl3 in a suspension
of activated zirconia in toluene at room temperature overnight
(Scheme 1). The chloride content of the catalyst was determined
by Mohr titration. In this method, the sample solution was titrated
against a solution of silver nitrate of known concentration (0.1 M)
using K2CrO4 as an indicator. The results showed that 2 chloride
ions per BiCl3 were released during the synthesis of the catalyst.
This suggested the presence of BiCl instead of BiCl3 in the synthe-
sized catalytic system.
3.1.4. XRF analysis of the catalyst
Elemental analysis of BiCl3-ZrO2 was performed by means of x-
ray fluorescence (XRF) analysis (Table 1). The chemical/elemental
analysis of BiCl3-ZrO2 indicated that ZrO2 content was 76.82 wt %
whereas Bi and Cl contents were 8.75 wt %, 0.62 wt % respectively.

266
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Fig. 4. EDX analysis of the catalyst (BiCl3-ZrO2).
to activated ZrO2 indicates filling of some of the pores by the BiCl3
component preventing N2 adsorption in the filled pores.
The pore volumes for ZrO2, activated ZrO2 and BiCl3-ZrO2
obtained were 0.0026, 0.0339 and 0.033 ccg−1 respectively.
3.1.6. DSC-TGA of catalyst (BiCl3-ZrO2)
DSC analysis of BiCl3-ZrO2 showed an irreversible endothermic
peak at 100 ◦C indicating the loss of water molecules from zirconia
framework (Fig. 6a). The catalyst did not show any other transi-
tion up to 500 ◦C indicating the stability of the catalyst up to this
temperature.
A significant decrease in the weight percentage of 5.57 (up to
250 ◦C) as evident from the TG curve (Fig. 6b) was attributed to the
loss of adsorbed moisture on the surface of the catalyst. In addition,
weight loss of 6.60% at ∼700 ◦C showed the transformation of BiCl3
to its oxide at higher temperatures.
Fig. 2. (a) The powder XRD pattern of zirconia (b) XRD pattern of fresh catalyst
(BiCl3-ZrO2) (c) XRD pattern of the catalyst after six catalytic cycles.
Table 1
Summary of composition of BiCl3-ZrO2 determined by XRF analysis.
3.2. Catalytic evaluation
Catalyst
Composition of catalyst by XRF
ZrO2
76.82
Bi
8.75
Cl
0.62
The catalytic activity of BiCl3-ZrO2 was evaluated using
model reaction of 3-methyl-5-phenoxy-1-phenylpyrazole-4-
carbaldehyde (1 mmol) and 5-acetyl-1,3-dimethyl-2,4,6-pyrimidi-
netrione (1 mmol). The effect of various catalysts, solvents, per-
centage of BiCl3 loading, amount of BiCl3-ZrO2 and temperature
were studied to optimize the reaction condition.
BiCl3-ZrO2
Further, Cl/Bi weight ratio and Bi/ZrO2 weight ratio were found to
be 0.07 and 0.11 respectively.
3.1.5. BET surface area analysis
Brunauer–Emmett–Teller (BET) surface areas of ZrO2, activated
ZrO2 and BiCl3-ZrO2 are given in Fig. 5. The surface area of the acti-
3.2.1. Effect of different catalysts
Initially, a blank reaction was carried out using 1 equiv. each of
active methyl compound (4a) and aldehyde (3a). These reactants
were stirred at 80 ◦C under solvent-free conditions for 8 h and only
22% of the yield of the product (5a) was obtained (Table 2, entry 1).
vated ZrO2 and BiCl3-ZrO2 catalyst are 24 m2 g−1 and 21.9 m2 g−1
,
as expected, higher than that of the bulk ZrO2 material (1.8 m2 g−1).
The decrease in surface area of the BiCl3 loaded ZrO2 in comparison
Fig. 3. SEM images (a and b) of fresh catalyst (BiCl3-ZrO2) and (c) of recycled catalyst.

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
267
Fig. 5. Nitrogen adsorption isotherm and pore volume analysis of (a) ZrO2 (b) activated ZrO2 and (c) BiCl3-ZrO2.
Table 2
Table 3
The effect of various catalysts on the model reaction under thermal solvent-free
condition.
Solvent effect on the synthesis of 5a in the presence of BiCl3-ZrO2.
Entrya
Solvent
Timeb
Yieldc
Entrya
Catalyst
Timeb
Yieldc (%)
1
2
3
4
5
6
7
8
9
H2O
CH3CH2COOCH3
CH3CN
CH2Cl2
THF
16 h
20 h
16 h
18 h
18 h
7 h
9 h
9 h
15 min
22
45
49
48
45
78
74
72
92
1
–
8 h
22
2
3
ZrO2
FeCl3
4 h
2 h
Trace
48
4
NiCl2
1 h
54
5
ZnCl2
1 h
46
CH3OH
6
BiNO3
3 h
26
CH3CH2OH
(CH3)2CHOH
No solvent
7
8
AlCl3
CuCl2
2 h
6 h
Trace
25
9
Sulfated zirconia
BiCl3
BiCl3-SiO2
BiCl3-TiO2
BiCl3-ZrO2
50 min
2.5 h
30 min
3 h
62
68
90
42
a
Reaction of 3-methyl-5-phenoxy-1-phenylpyrazole-4-carbaldehyde (1 mmol)
with 5-acetyl-1,3-dimethyl-2,4,6-pyrimidinetrione (1 mmol) in the presence of
BiCl3-ZrO2 (80 mg).
10
11
12
13
b
Reaction progress monitored by TLC.
Isolated yield.
15 min
92
c
a
Reaction of 3-methyl-5-phenoxy -1-phenylpyrazole-4- carbaldehyde (1 mmol)
with 5-acetyl-1,3-dimethyl-2,4,6-pyrimidinetrione (1 mmol) in the presence of
80 mg of catalyst.
product was obtained after 3 h (Table 2, entry 12). However, max-
imum yield of the product was obtained using BiCl3-ZrO2 as the
catalyst (Table 2, entry 13).
b
Reaction progress monitored by TLC.
c
Isolated yield.
3.2.2. Effect of solvents
The same reaction was then carried out using ZrO2 as the promoter
and again trace amount of the product was obtained (Table 2, entry
2). Using FeCl3, NiCl2 and ZnCl2, reaction completed in 1–2 h but
with unsatisfactory product yield (Table 2, entries 3–5). BiNO3,
AlCl3 and CuCl2 also could not give satisfactory results (Table 2,
entries 6–8). Sulfated zirconia and BiCl3 afforded products only in
moderate yield (Table 2, entries 9, 10). When the reaction was car-
ried out using BiCl3 loaded on silica (BiCl3-SiO2) good yield (90%)
of the product was obtained in 30 min (Table 2, entry 11) but
with BiCl3 loaded on titania ((BiCl3-TiO2) poor yield (42%) of the
In our initial selection, we used BiCl3-ZrO2 in water for the model
reaction but product was obtained with trace yield (Table 3, entry
1). Using ethyl acetate, acetonitrile, dichloromethane, tetrahydro-
furan, only moderate yields were obtained (Table 3, entries 2–5).
In polar solvents CH3OH, CH3CH2OH and (CH3)2CHOH, product
formation increased to some extent but with unsatisfactory yield
(Table 3, entries 6–8). In this study, it was observed that solvent-
free condition (Table 3, entry 9) was more efficient and superior
condition with respect to reaction time and yield.
Fig. 6. (a) DSC of catalyst (b) TG curve of catalyst (BiCl3-ZrO2).

268
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Table 4
Effect of BiCl3 loading on support ZrO2 for the synthesis of 5a.
Entrya
BiCl3-ZrO2 (%w/w)
Timeb
Yieldc (%)
1
2
3
4
5
7
1.2 h
1 h
45 min
15 min
15 min
64
76
82
92
90
10
15
20
25
a
Reaction of 3-methyl-5-phenoxy-1-phenylpyrazole-4-carbaldehyde (1 mmol)
with 5-acetyl-1,3-dimethyl-2,4,6-pyrimidinetrione (1 mmol) in the presence of
BiCl3-ZrO2 (80 mg).
b
Reaction progress monitored by TLC.
Isolated yield.
c
Table 5
Effect of amount of catalyst on the synthesis of 5a in thermal solvent-free condition.
Entry
BiCl3-ZrO2 (mg)
Timea
Yieldb
1
2
3
4
5
20
40
60
80
100
1.5 h
1 h
40 min
15 min
15 min
54
68
94
92
92
Scheme 2. Synthesis of pyrazolyl chalcones (5a-t) using BiCl3-ZrO2 under thermal
solvent-free conditions.
a
Reaction progress monitored by TLC.
Isolated yield.
3.3. Synthesis of pyrazolyl chalcones via Claisen–Schmidt
condensation in the presence of BiCl3-ZrO2
b
To explore general validity of our methodology, BiCl3-ZrO2 was
employed for the synthesis of series of pyrazolyl chalcones (5a-t)
using substituted aldehydes (3a-d) and heterocyclic active methyl
ketones (4a-e) under the optimized reaction conditions (Scheme 2).
The reaction proceeded efficiently and afforded products in excel-
lent yields (86-92%) in a short span of time period (15–25 min)
(Table 7).
3.2.3. Effect of loading of the catalyst
The catalyst loading was varied as 7, 10, 15, 20 and 25% w/w of
BiCl3 supported on ZrO2 (Table 4). With increase in catalyst loading,
the yield was found to increase up to 20% further increase has no
effect on the yield. The optimum catalyst loading was thus taken as
20%.
The structure of all novel compounds (5a-t) was confirmed on
the basis of spectral analysis (FT-IR, 1H NMR, 13C NMR and mass
spectra). The infrared (IR) spectrum of 5a showed sharp and strong
absorption bands of carbonyl group of barbituric and propenone
moiety at 1716 cm−1 and 1650 cm−1 respectively. Another sharp
and strongly absorbed band at 1615 cm−1 was due to carbon-
carbon double bond of ␣, ␤-unsaturated system. The 1H NMR
spectrum showed trans olefinic protons Ha and Hb at ı 8.32
(J = 15.6 Hz) and ı 8.27 (J = 16.0 Hz), as two ortho-coupled dou-
blets. The value of spin–spin coupling constant Jab in the range
15–16 Hz indicated the E-configuration of chalcone. The aromatic
protons of the pyrazole moiety were present in the form of mul-
tiplet at ı 6.96–8.27. Two NCH3 group protons of barbituric acid
moiety were discernible as sharp singlet at ı 3.36 whereas pro-
tons of CH3 group of pyrazole unit appeared as another sharp
singlet at ı 2.52. The 13C NMR spectrum showed signals at ı 176.23
and 27.34 for carbonyl and methyl group of 1,3-dimethyl barbi-
turic acid respectively. Another signal at ı 182.70 was for carbonyl
group of ␣, ␤-unsaturated system. Other carbon signals appeared
at their appropriate positions and are discussed in experimental
section. Further confirmation for 5a was obtained by mass spec-
trum, which showed molecular ion peak as M+ + 1 peak at m/z
459.14.
3.2.4. Effect of the amount of catalyst
Similarly, amount of catalyst was varied from 20 to 100 mg, the
yield was found to increase with increase in amount up to 80 mg,
and further increase in amount did not improve the product yield
and reaction time (Table 5). The optimum amount of catalyst for
the reaction was selected as 80 mg.
3.2.5. Effect of temperature
The reaction temperature is an important factor which affects
the reaction rate under solvent-free condition. The increase of
temperature can enhance stimulation of molecules leading to
improvement of product yield and reaction time. As shown in
Table 6, the effect of this variable was positive relevant to tem-
perature from 25 ◦C to 80 ◦C. Further, increase in the temperature
reduced the time period but with the formation of a charred prod-
uct. Therefore, the optimum temperature was found to be 80 ◦C and
employed in the experiment.
Table 6
Effect of temperature on the synthesis of 5a in solvent-free condition.
A general plausible mechanism for synthesis of pyrazolyl chal-
cones in the presence of BiCl3-ZrO2 has been shown in Scheme 3.
Entrya
Temperature
RT
Timeb
Yieldc
1
2
3
4
5
–
5 h
2.5 h
15 min
10 min
–
40 ◦
60 ◦
80 ◦
C
C
C
58
72
92
64
3.4. Reusability of catalyst
100 ◦
C
To establish the heterogeneous character of the catalyst,
recycling experiment was employed using model reaction. After
completion of reaction, the catalyst was recovered by filtration,
washed with ethanol and dried under vacuum. The recovered cat-
alyst was reused for six cycles with a minor loss in catalytic activity
(Fig. 7).
a
Reaction of 3-methyl-5-phenoxy-1-phenylpyrazole-4-carbaldehyde (1 mmol)
with 5-acetyl-1,3-dimethyl-2,4,6-pyrimidinetrione (1 mmol) in the presence of
BiCl3-ZrO2 (80 mg).
b
Reaction progress monitored by TLC.
Isolated yield.
c

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
269
Table 7
The reaction of 5-aryloxy-3-methyl-1-phenyl-pyrazole-4-carbaldehydes and cyclic active methyl compounds in presence of BiCl3-ZrO2 under thermal solvent-free conditions.
Entry
Aldehyde
Ketone
Product
Timea
(min)
Yieldb
(%)
(3a-d)
(4a-e)
(5a-t)
1
3a
3a
3a
4a
4b
4c
15
20
20
92
92
90
5a
2
5b
3
5c
5d
5e
4
3a
4d
17
90
5
3a
4e
20
92

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S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
Table 7 (Continued)
Entry
Aldehyde
Ketone
Product
Timea
Yieldb
6
3b
4a
15
92
5f
7
3b
4b
18
90
5g
8
3b
4c
20
88
5h
5i
9
3b
4d
15
90
10
3b
4e
15
88
5j

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
271
Table 7 (Continued)
Entry
Aldehyde
Ketone
Product
Timea
Yieldb
11
3c
4a
20
88
5k
5l
12
3c
4b
25
86
13
3c
4c
25
86
5m
5n
14
3c
4d
17
90
15
3c
4e
20
92
5o

272
S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
Table 7 (Continued)
Entry
Aldehyde
Ketone
Product
Timea
Yieldb
16
3d
4a
15
90
5p
5q
17
3d
4b
25
86
18
3d
4c
25
88
5r
5s
5t
19
3d
4d
20
88
20
3d
4e
15
90
a
Reaction progress monitored by TLC.
Isolated yield.
b

S. Tarannum, Z.N. Siddiqui / Journal of Molecular Catalysis A: Chemical 394 (2014) 262–273
273
Acknowledgements
The authors are thankful to Centre of Nanotechnology, Depart-
ment of Applied Physics and University Sophisticated Instrument
Facility (USIF), AMU, Aligarh for providing powder x-ray diffrac-
tometer and SEM-EDX facilities. The authors would also like to
thank SAIF, Punjab University, Chandigarh, for providing spectral
data. SAIF, IIT Bombay is gratefully acknowledged for providing
XRF analysis data. UGC, New Delhi, is gratefully acknowledged for
awarding research fellowship to ST.
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In summary, we have synthesized and characterized heteroge-
neous version of BiCl3 (BiCl3-ZrO2). The catalytic activity of the
catalyst was explored by synthesizing a library of novel pyra-
zolyl chalcones in excellent yield. The wide scope, practicability,
enhanced rate of reaction, operational simplicity and reusability
of catalyst provide attractive approach for applications in other
organic transformations in the future.