Amberlite-supported L-prolinate: A novel heterogeneous organocatalyst for the three-component synthesis of 4H-pyrano[2,3-c]pyrazole derivatives

Article abstract of DOI:10.1134/S1070363217030252

This report describes a new and convenient procedure for heterogenization of L-proline organocatalyst, which is based on non-covalent immobilization of L-proline on the surface of anion-exchange resin amberlite IRA900OH (AmbIRA900OH) as an efficient, chea

Full text of DOI:10.1134/S1070363217030252

ISSN 1070-3632, Russian Journal of General Chemistry, 2017, Vol. 87, No. 3, pp. 539–545. © Pleiades Publishing, Ltd., 2017.
Amberlite-Supported L-Prolinate: A Novel Heterogeneous
Organocatalyst for the Three-Component Synthesis
1
of 4H-Pyrano[2,3-c]pyrazole Derivatives
a
b
S. Nazari * and M. Keshavarz
a
Department of Chemistry, Sousangerd Branch, Islamic Azad University, Sousangerd, Iran
b
Department of Gas and Petroleum, Yasouj University, Gachsaran, Iran
*
e-mail: Chem.mosadegh@gmail.com
Received May 3, 2016
Abstract—This report describes a new and convenient procedure for heterogenization of L-proline
organocatalyst, which is based on non-covalent immobilization of L-proline on the surface of anion-exchange
resin amberlite IRA900OH (AmbIRA900OH) as an efficient, cheap, and commercially accessible cationic
polymer support. The ion-pair immobilization of L-proline on the surface of amberlite IRA900OH was
2
achieved by treatment of a MeOH/H O solution of L-proline with amberlite IRA900OH at 60°C. L-Proline
anion was exchanged with hydroxide ion and immobilized via ionic interaction between the carboxylate group
of L-prolinate and quaternary ammonium cation of the cationic amberlite support. The prepared heterogeneous
organocatalyst was characterized by FTIR, TGA, DTG, XRD, and elemental analysis techniques. The amberlite-
supported catalyst was used as an efficient, reusable, and cheap catalyst for the one-pot three-component
synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol. The catalyst can be easily recovered and reused
by simple filtration for several successive runs with no significant loss of catalytic activity.
Keywords: L-proline, anion-exchange resin, organocatalyst, 4H-pyrano[2,3-c]pyrazole, heterogeneous catalyst
DOI: 10.1134/S1070363217030252
INTRODUCTION
[6, 7], biphasic immobilization [8, 9], and self-sup-
ported gel-types and ion-pair immobilization [10, 11]
or covalent linkage on supports such as polymers
[12, 13], silica [14, 15], magnetite [16], and ionic
liquids [17, 18].
Organocatalysis has received great attention during
the last years [1]. Organocatalysts have several impor-
tant advantages, since they are usually robust, in-
expensive, readily available, and nontoxic [2]. Organo-
catalysts are metal-free organic compounds of
relatively low molecular weight and simple structure
capable of promoting a reaction in substoichiometric
amount. At the same time, immobilization and
recycling of organocatalysts has experienced a very
good growth [3, 4]. Indeed, organocatalysts are usually
used in substantial amounts, in some cases up to
One of the most important challenges with catalyst
immobilization is to retain the activity and stereoselec-
tivity of the immobilized catalyst. Moreover, another
important aspect of immobilized catalysts is separa-
tion, which can be achieved by a simple operation such
as filtration [19]. Among enantioselective organo-
catalysts, proline and its derivatives have attracted
huge interest and development in the recent years.
3
0 mol %. This is the main reason for the need of an
efficient immobilization and recycling procedure.
Moreover, immobilization of an organocatalyst may
enhance its activity and stereoselectivity [5].
The first asymmetric reaction using L-proline was
reported in the early 1970s [20]; 30 years later, proline
and proline derivatives have been extensively used,
especially in asymmetric organocatalyzed aldol-type
reactions [21–23]. It should be noted that the
immobilization approach requires the use of synthetic
derivatives that are more expensive than proline. The
latter is commercially available at low cost but is often
employed at high catalyst loading. However, attempts
Immobilization of organocatalyst onto a solid support
can be accomplished by either non-covalent linkage
such as immobilization via hydrophobic interaction
1
The text was submitted by the authors in English.
5
39

5
40
NAZARI, KESHAVARZ
to improve or modify its catalytic behavior, taking
advantage of specific properties of the support, would
justify immobilization in many instances [24].
Nicolet AVATAR 370 spectrophotometer. The elemental
analyses (C, H, and N) were obtained with a Heraeus
CHN-O-Rapid analyzer. Thermogravimetric and dif-
ferential thermogravimetric (TG–DTG) analysis was
performed on a Netsch STA449c instrument (sample
weight ~10 mg; heating from room temperature to
Pyrans belong to an important class of heterocyclic
compounds which exhibit wide range of biological
activities [25] and are widely used as cosmetics,
pigments, and potentially biodegradable agrochemicals
600°C at a rate of 10 deg/min; alumina sample holders).
[26]. In view of great importance of pyran derivatives,
Preparation of the [Amb]-L-prolinate catalyst.
in recent years efforts have been made to develop new
methodologies for the synthesis of these compounds.
Most of these methods utilize various catalysts. The
most used methods for the synthesis of pyrano[2,3-c]-
pyrazoles involve three-component cyclocondensation
of 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
with aldehydes and malononitrile. Recently, some new
catalysts have been reported for the preparation of this
class of compounds [27–32]. Some of these methods
suffer from drawbacks such as unsatisfactory yields,
extended reaction times, elevated temperatures, tedious
work-up, harsh reaction conditions, and the use of
expensive reagents. Each method has its own advan-
tages and disadvantages; however, search for a better
catalyst for the synthesis of pyrano[2,3-c]pyrazoles
continues in terms of operational simplicity, reusability,
economic viability, and environmental safety.
Amberlite IRA-900OH (grain size 16–50 mesh, 1 g)
was dispersed in 10 mL of a 1 M solution of L-proline
in aqueous methanol (1 : 1), and the suspension was
heated at 60°C for 6 h. The catalyst was filtered off,
washed with aqueous methanol (1 : 1; 2 × 10 mL) and
water (2 × 10 mL), and dried under reduced pressure
[35–38].
General procedure for the [Amb]L-prolinate-
catalyzed multicomponent synthesis of 4H-pyrano
[
2,3-c]pyrazoles. A round-bottom flask was charged
with 5 mL of ethanol, 1 mmol of 3-methyl-1-phenyl-
,5-dihydro-1H-pyrazol-5-one, 1 mmol of the corres-
ponding aldehyde, and 1 mmol of malononitrile, 0.08 g
10 mol %) of [Amb]L-prolinate was added, and the
4
(
resulting suspension was magnetically stirred on
heating under reflux until the reaction was complete
(
TLC; n-hexane–ethyl acetate, 3 : 1). The catalyst was
Due to the current challenges for developing
environmentally benign synthetic processes and in
continuation of our research on applications of ion-
exchange resins for click synthesis of 1,4-disubstituted-
filtered off and washed with hot ethanol (2 × 5 mL).
The recovered catalyst was washed with acetone,
dried, and stored for further recycling. Crystals of pure
4H-pyrano[2,3-c]pyrazole derivatives separated from
the filtrate. Some products were described previously,
and their melting points were compared with the
reported values [27–32]. The newly synthesized
compounds were characterized by IR and NMR data.
Given below are spectral data for some selected 4H-
pyrano[2,3-c]pyrazole derivatives.
1
H-1,2,3-triazoles [33, 34], we would like to explore
the catalytic activity of the ion-exchange resin
Amberlite IRA900OH (AmbIRA900OH) as a cationic
polymer support for the ion-pair immobilization of L-
proline anion via ionic interaction between the car-
boxylate group of L-prolinate and quaternary
ammonium cation of the cationic Amb support. This
heterogeneous catalyst was used as an efficient,
reusable, cheap, and commercially accessible catalyst
for the one-pot three-component synthesis of 4H-
pyrano[2,3-c]pyrazole derivatives in ethanol.
6
-Amino-4-(4-methoxyphenyl)-3-methyl-1-phenyl-
,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile
2e). Yield 0.32 g (89%), pale yellow powder. IR spec-
1
(
–1
trum (KBr), ν, cm : 3394, 3325, 3059, 2975, 2193,
1
1
661, 1597, 1515, 1397, 1258. H NMR spectrum, δ,
ppm: 1.78 s (3H, CH ), 3.74 s (3H, OCH ), 4.62 s (1H,
CH), 6.89 d (2H, CH, J = 8.5 Hz), 7.15 s (2H, CH),
.17 s (2H, NH ), 7.31 t (1H, CH, J = 7.6 Hz), 7.49 t
EXPERIMENTAL
3
3
1
The H NMR spectra were recorded on a Bruker
7
2
Avance DPX 400 spectrometer (400 MHz). The X-ray
diffraction (XRD) patterns were recorded on a Philips
13
(
2H, CH, J = 7.6 Hz), 7.77 d (2H, CH, J = 8.5 Hz). C
NMR spectrum, δ , ppm: 12.6, 35.9, 55.1, 58.6, 98.9,
C
X’PERT-Pro-MPD diffractometer using Cu K radia-
α
1
1
13.8, 119.9, 120.1, 126.2, 128.8, 129.4, 135.6, 137.5,
45.4, 158.2, 159.3.
tion (λ = 1.542 Å); A continuous scan mode was used
to collect reflections intensities in the range 5° < 2θ <
4
4
0°. Fourier transform infrared (FT-IR) spectra (400–
000 cm ) were obtained in KBr using a Thermo
6-Amino-3-methyl-4-(3-nitrophenyl)-1-phenyl-1,4-
dihydropyrano[2,3-c]pyrazole-5-carbonitrile (2g).
–
1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017

AMBERLITE-SUPPORTED L-PROLINATE
541
Scheme 1.
O
0
.01 M L-proline in
O
PS
N
OH
PS
N
C
MeOH−H O (1 : 1)
2
6
0°C, 6 h
HN
[Amb]OH
[Amb]L-Prolinate
Yield 0.33 g (88%), yellow powder. IR spectrum
Thermogravimetric analysis (TGA) and differential
thermal analysis (DTG) associated with the decom-
position profiles of AmbIRA900OH, L-proline, and
[Amb]L-prolinate hybrid in a nitrogen atmosphere and
the XRD pattern of [Amb]L-prolinate provided further
evidences for the immobilization of L-prolinate anion
onto the polymer surface (for more information, see
[35–38]).
–
1
(
1
KBr), ν, cm : 3436, 3296, 3098, 2190, 1651, 1589,
517, 1446, 1386, 1349, 1258, 1119. H NMR spec-
1
trum, δ, ppm: 1.90 s (3H, CH ), 4.81 s (1H, CH), 4.83
3
s (2H, NH ), 7.36–7.37 m (1H, CH), 7.48–7.51 m (2H,
2
CH), 7.56–7.59 m (1H, CH), 7.66–7.67 m (3H, CH),
3
13
8
.13 s (1H, CH), 8.19 d (1H, CH, J = 7.2 Hz).
C
NMR spectrum, δ , ppm: 13.0, 36.8, 57.6, 98.0, 120.3,
C
1
1
20.5, 122.7, 126.7, 129.7, 130.7, 135.2, 137.9, 144.5,
45.6, 146.4, 184.4, 160.3.
The effect of [Amb]L-prolinate (2–15 mol %) on
the model reaction of benzaldehyde with malononitrile
and 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
was studied under different conditions (Table 1). The
results clearly indicated that the best yield of 6-amino-
RESULTS AND DISCUSSION
Catalyst preparation. The procedure for ion-pair
immobilization of L-prolinate anion on the cationic
polymer resin is illustrated by Scheme 1. The strategy
consists of building up suitable heterogeneous macro-
porous polymer-supported L-prolinate catalyst on the
surface of commercially available amberlite IRA-
3
-methyl-1,4-diphenyl-1,4-dihydropyrano[2,3-c]pyra-
zole-5-carbonitrile (2a) was achieved by caring out the
reaction in the presence of 10 mol % of [Amb]L-
prolinate under reflux in ethanol (Table 1, run no. 9).
The yield smoothly increased with the catalyst load up
to 10 mol %, while the use of larger amounts of the
catalyst (15 mol %) did not improve the yield; reduc-
tion of he amount of the catalyst led to decreased yield.
9
00OH (16–50 mesh). Preparation of the hetero-
geneous polymer-supported L-prolinate catalyst by this
procedure is facile and straightforward. Typically,
AmbIRA900OH was treated with a 0.01 M solution of
L-proline in aqueous methanol at 60°C.
In order to explore the scope of this reaction, we
conducted the reaction with a series of aromatic
aldehydes bearing different substituent groups under
the optimal conditions using 10 mol % of [Amb]L-
prolinate in ethanol under reflux (Scheme 2, Table 2).
The ion–pair immobilization of L-prolinate anion
on the polymer resin was confirmed by comparison of
the FT-IR spectra of pure AmbIRA900OH, initial
L-proline, and [Amb]L-prolinate hybrid (see figure).
Characteristic stretching frequencies of L-proline appeared
1
–
–1
at 3056 (NH), 1622 (COO , asym.), and 1380 cm
–
(COO , sym.). These bands are observed as new peaks
in the FT-IR spectrum of [Amb]L-prolinate hybrid when
2
compared with the spectrum of pure AmbIRA900OH
–
(
Fig. 1). The asymmetric and symmetric COO
stretching bands of [Amb]L-prolinate were found to
–
1
shift to lower frequencies, 1615 and 1375 cm ,
–
1
3
respectively. The band at 3056 cm corresponding to
N–H stretching vibrations of L-proline did not change
its position in the spectrum of [Amb]L-prolinate.
These findings confirmed that L-prolinate anion was
successfully loaded onto the polymer surface through
ionic interaction (ion-pair binding) between the
carboxylate group of L-prolinate and quaternary
ammonium cation of the cationic Amb support.
–1
ν, cm
FT-IR spectra of (1) [Amb]OH, (2) [Amb]L-prolinate, and
(3) L-proline.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017

5
42
NAZARI, KESHAVARZ
Table 1. Reaction of benzaldehyde with malononitrile and 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one in the presence
of [Amb]L-prolinate under different conditions
O
O
PS
N
C
H C
3
CH3
O
CN
HN
N
N
H
+
+ NC
CN
N
N
Condition
O
NH2
Ph
O
Ph
a
Entry
Conditions
No solvent
Temperature, °C
100
[Amb]L-prolinate, mol %
Time, min
Yield of 2a, %
1
2
3
4
5
6
7
8
9
2
2
50
45
40
45
35
30
35
25
15
15
50
60
65
65
68
70
80
90
98
97
CH
CH
2
3
Cl
2
Reflux
Reflux
65
CN
2
THF
2
DMF
100
2
H
H
2
2
O/DMF
O
100
5
Reflux
Reflux
Reflux
Reflux
5
EtOH
EtOH
EtOH
5
10
15
1
0
a
Yield of isolated pure product.
All the products were cleanly isolated by simple
filtration and recrystallization from hot ethanol. The
data in Table 2 show that aromatic aldehydes with both
electron-donating and electron-withdrawing groups
smoothly reacted under the given conditions to give
target products 2a–2s in good to excellent yields.
from the active methylene group of malononitrile
giving rise to carbanion which attacks the carbonyl
carbon atom of aromatic aldehyde, and the subsequent
loss of water molecule yields α-cyanocinnamonitrile
derivative. In the second step, [Amb]L-prolinate catalyst
reacts with 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-
5
-one to produce enamine intermediate. Michael
Scheme 3 shows a probable reaction mechanism to
demonstrate the role of the catalyst. The formation of
addition of the latter to the Knoevenagel product,
followed by ring closure and deprotonation, yields
final 4H-pyrano[2,3-c]pyrazole.
4
H-pyrano[2,3-c]pyrazole derivatives involves
simultaneously Knoevenagel condensation, Michael
addition, and intramolecular cyclization. In the first
step, the [Amb]L-prolinate catalyst abstracts a proton
As a true heterogeneous catalyst, supported catalyst
should not leach into the reaction mixture, and the
Scheme 2.
O
O
PS
N
C
CH3
Ar
H C
3
O
HN
CN
N
+
+
Ar
H
NC
CN
N
N
EtOH, reflux
0−25 min
N
1
O
NH2
Ph
O
Ph
1
2a−2s
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017

AMBERLITE-SUPPORTED L-PROLINATE
543
Table 2. Synthesis of 4H-pyrano[2,3-c]pyrazole derivatives catalyzed by [Amb]L-prolinate
mp, °C
a
Entry
Ar
Product no.
Time, min
Yield, %
found
reported
167–171
1
2
3
4
5
6
7
8
9
Ph
2a
2b
2c
2d
2e
2f
15
20
18
10
25
25
10
12
18
15
18
15
12
15
25
20
15
15
18
98
92
94
87
89
86
98
96
89
87
94
90
92
85
89
92
89
90
93
168–170
4-PhC
6
H
4
190–192
170–171
235–237
241–243
194–196
190–192
196–198
142–144
174–176
159–161
180–182
171–173
215–217
205–207
206–208
184–186
217–220
178–181
190–192
177–179
234–236
242–243
194–196
189–191
197–198
140–142
175–178
158–161
182–184
170–172
217–218
206–207
207–209
184–186
217–219
178–180
4-MeC
4-CHOC
4-MeOC
3,4,5-(MeO)
6 4
H
6 4
H
6
H
4
3
6 2
C H
3-O
4-O
2
2
NC
6
H
H
4
4
2g
2h
2i
NC
6
2-ClC
4-ClC
3-ClC
6
6
6
H
4
1
0
1
H
H
4
4
2j
1
2k
2l
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
2,4-(Cl)
4-FC
4-CNC
2 6 3
C H
6
H
4
2m
2n
2o
2p
2q
2r
2s
6 4
H
4-OHC
6
H
H
4
4
2-OHC
6
4-BrC
6
H
4
4-CNC
6
H
4
Naphthalen-2-yl
a
Isolated pure product.
Table 3. Comparison of the efficiency of various catalysts and conditions for the reaction of benzaldehyde with malononitrile
and 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one
Catalysts and reaction conditions
Time, min
Yield, %
98
Reference
This work
[27]
[
Amb]L-prolinate (10 mol %), EtOH, reflux
15
25
60
35
15
11
20
SBPPSP, EtOH/H
2
O/100 °C, reflux
O or EtOH, reflux
SB(DBU)Cl, EtOH, rt
Nano-TiO / H14[NaP
Nano-La0.7Sr0.3MnO
97
H
14[NaPW12
O
40], H
2
93
[28]
94
[29]
2
5
W
30
O
110], EtOH, ultrasound, 40°C
97
[30]
3
, EtOH, ultrasound, 25°C
89
[31]
SnS-NPs@AC, EtOH, reflux
91
[32]
recyclability of supported catalyst is also important. To
estimate recyclability of the proposed catalyst, the
reaction of 3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-
5-one with benzaldehyde and malononitrile in ethanol
was selected again as model. The results are given
below.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017

5
44
NAZARI, KESHAVARZ
Scheme 3.
O
O
O
O
CN
CN
NC
NC
H
H
C
+
Ar
H
Ar
H
N
H
H
−
H O
2
O
C
O
Ar
O
O
+
H C
+
..
3
H
CH3
C
+
N
O
H
C
N
Ar
N
H
O
CN
O
N
Ph
CN
CN
N
H
N
C
N
H
N
N
N
Ph
Ph
O
CH3
O
+
C
Ar
O
Ar
O
H C
H C
3
3
N
H
Ar
O
CH3
CN
NH2
H
H
CN
NC
HN
N
N
N
C
N
N
N
N
O
Ph
Ph
Ph
pyrazol-5-one. The reaction times for the preparation
of 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano-
Run no.
1
2
3
4
5
6
7
8
Time(min) 15 15 20 20 20 30 25 25
Isolated
yield, %
[2,3-c]pyrazole-5-carbonitrile by our procedure are
shorter than in reported methods. The best yield and
short reaction time is attributed to the high efficiency
of [Amb]L-prolinate.
98 98 97 97 96 95 94 93
After completion of the reaction, the mixture was
filtered, and the recovered catalyst was washed with
acetone and dried before using for next consecutive
runs (7 runs). Almost consistent activity was observed
over 8 consecutive runs. Thus, [Amb]L-prolinate can
be reused up to 8 runs without need to reload, and the
difference in the yields between the first and eighth
runs is only 5%. The nitrogen content of the fresh and
reused catalysts was measured by elemental analysis. It
was found that the catalyst lost only 3% of nitrogen
after 8 runs. This is a good proof for very low leaching
amount of L-proline organocatalyst from [Amb]L-
prolinate catalyst into the reaction mixture during
CONCLUSIONS
In conclusion, we have developed a novel and
highly efficient protocol for one-pot three component
synthesis of 4-H-pyrano[2,3-c]pyrazole derivatives in
ethanol at 80°C in the presence of amberlite-supported
L-prolinate as heterogeneous organocatalyst based on
non-covalent ion-pair immobilization of L-proline on
the surface of amberlite hydroxide. This methodology
made the organocatalyst to be mobile and flexible which
not only helped the supported catalyst to be as
powerful as its non-supported form, but also made it
easily recoverable by simple filtration. The catalyst can
be easily recovered and reused for several successive
fresh runs with no significant loss of catalytic activity.
8
runs, indicating that the catalytic ability of [Amb]L-
prolinate remained stable after 8 runs in agreement
with the recyclability study.
ACKNOWLEDGMENTS
Table 3 compares the efficiency of various catalysts
and conditions for the reaction of benzaldehyde,
malononitrile, and 3-methyl-1-phenyl-4,5-dihydro-1H-
The authors gratefully acknowledge the Research
Council of Yasouj University for financial support.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017

AMBERLITE-SUPPORTED L-PROLINATE
REFERENCES
cr800200t
545
2
0. Eder, U. and Sauer, G.R., Angew. Chem., Int. Ed. Engl.,
1
. Enantioselective Organocatalysis: Reactions and Experi-
mental Procedures, Dalko, P.I., Ed., Weinheim: Wiley
VCH, 2007.
1971, vol. 10, p. 496. doi 10.1002/anie.197104961
2
1. Sakthivel, K., Notz, W., Bui, T., and Barbas, C.F.,
J. Am. Chem. Soc., 2001, vol. 123, p. 5260. doi 10.1021/
ja010037z
2. List, B., Chem. Rev., 2007, vol. 107, p. 5413. doi
10.1021/cr078412e
3. Dondoni, A. and Massi, A., Angew. Chem., Int. Ed.,
2
3
4
5
. Pellissier, H., Tetrahedron, 2007, vol. 63, p. 9267. doi
1
0.1016/j.tet.2007.06.024
2
2
2
. Gruttadauria, M., Giacalone, F., and Noto, R., Chem.
Soc. Rev., 2008, vol. 37, p. 1666. doi 10.1039/B800704G
. Cozzi, F., Adv. Synth. Catal., 2006, vol. 348, p. 1367.
2008, vol. 47, p. 4638. doi 10.1002/anie.200704684
doi 10.1002/adsc.200606096
4. Jimeno, C., Sayalero, S., Pericàs, M.A., Heterogenized
Homogeneous Catalysts for Fine Chemicals
Production: Materials and Processes, Barbaro, P. and
Liguori, F., Eds., Dordrecht: Springer, 2010, p. 123.
. Gruttadauria, M,. Giacalone, F., Mossuto Marculescu, A.,
Salvo, A.M.P., and Noto, R., Arkivoc, 2009, part (viii),
p. 5.
6
. Huang, J., Zhang, X., and Armstrong, D.W., Angew.
Chem., Int. Ed., 2007, vol. 46, p. 9073. doi 10.1002/
anie.200703606
25. Bonsignore, L., Loy, G., Secci, D., and Calignano, A.,
Eur. J. Med. Chem., 1993, vol. 28, p. 517. doi
10.1016/0223-5234(93)90020-F
7
8
9
. Liu, K., Haeussinger, D., and Woggon, W.D., Synlett,
26. Khaksar, S., Rouhollahpour, A., and Talesh, S.M.,
J. Fluorine Chem., 2012, vol. 141, p. 11. doi 10.1016/
j.jfluchem.2012.05.014
27. Niknam, K., Borazjani, N., Rashidian, R., and Jamali, A.,
Chin. J. Catal., 2013, vol. 34, p. 2245. doi 10.1016/
S1872-2067(12)60693-7
28. Heravi, M.M., Ghods, A., Derikvand, F., Bakhtiari, K.,
and Bamoharram, F.F., J. Iran. Chem. Soc., 2010,
vol. 7, p. 615. doi 10.1007/BF03246049
29. Hasaninejad, A., Golzar, N., Beyrati, M., Zare, A., and
Doroodmand, M.M., J. Mol. Catal. A., 2013, vol. 372,
p. 137. doi 10.1016/j.molcata.2013.02.022
30. Azarifar, D., Khatami, S.M., and Nejat-Yami, R., J. Chem.
Sci., 2014, vol. 126, p. 95. 10.1007/s12039-013-0548-x
31. Azarifar, A., Nejat-Yami, R., Al-Kobaisi, M., and
Azarifar, D., J. Iran. Chem. Soc., 2013, vol. 10, p. 439.
doi 10.1007/s13738-012-0177-1
32. Iravani, N., Keshavarz, M., Shojaeian Kish, H.A., and
Parandvar, R., Chin. J. Catal., 2015, vol. 36, p. 626. doi
10.1016/S1872-2067(14)60284-9
33. Keshavarz, M., Iravani, N., Ghaedi, A., Zarei Ahmady, A.,
Vafaei-Nezhad, M., and Karimi, S., SpringerPlus, 2013,
vol. 2, p. 64.
2
007, vol. 3, p. 2298.
. Huang, K., Huang, Z.Z., and Li, X.J., J. Org. Chem.,
006, vol. 71, p. 8320. doi 10.1021/jo061507g
2
. Guo, H.M., Cun, L.F., Gong, L.Z., Mi, A.Q., and Jiang, Y.Z.,
Chem. Commun., 2005, no. 11, p. 1450. doi 10.1039/
B417267A
1
1
1
1
1
0. Escuder, B., Rodriguez-Llansola, F., and Miravet, J.F.,
New J. Chem., 2010, vol. 34, p. 1044. doi 10.1039/
B9NJ00764D
1. Rodriguez-Llansola, F., Escuder, B., and Miravet, J.F.,
J. Am. Chem. Soc., 2009, vol. 131, p. 11 478. doi
1
0.1021/ja902589f
2. Gruttadauria, M., Giacalone, F., Marculescu, A.M., and
Noto, R., Adv. Synth. Catal., 2008, vol. 350, p. 1397.
doi 10.1002/adsc.200800090
3. Gruttadauria, M., Salvo, A.M.P., Giacalone, F.,
Agrigento, P., and Noto, R., Eur. J. Org. Chem., 2009,
p. 5437. doi 10.1002/ejoc.200900829
4. Zamboulis, A., Rahier, N.J., Gehringer, M., Cattoën, X.,
Niel, G., Bied, C., Moreau, J.J.E., and Man, M.W.C.,
Tetrahedron: Asymmetry, 2009, vol. 20, p. 2880. doi
1
0.1016/j.tetasy.2009.11.024
1
1
5. Khalafi-Nezhad, A., Shaikhi Shahidzadeh, E.,
3
3
3
3
4. Albadi, J. and Keshavarz, M., Synth. Commun., 2013,
Sarikhani, S., and Panahi, F., J. Mol. Catal. A: Chem.,
vol. 43, p. 2019. doi 10.1080/00397911.2012.671434
2
013, vol. 379, p. 1. doi 10.1016/j.molcata.2012.07.017
5. Keshavarz, M., J. Iran. Chem. Soc., 2016, vol. 13,
6. Yang, H., Li, S., Wang, X., Zhang, F., Zhong, X., and
Dong, Z., J. Mol. Catal. A: Chem., 2012, vol. 363,
p. 404. doi 10.1016/j.molcata.2012.07.017
7. Miao, W. and Chan, T.H., Adv. Synth. Catal., 2006,
vol. 348, p.1711. doi 10.1002/adsc.200606059
p. 553. doi 10.1007/s13738-015-0765-y
6. Keshavarz, M. and Vafaei-Nezhad, M., Catal. Lett.,
2
016, vol. 146, p. 353. doi 10.1007/s10562-015-1668-3
1
1
7. Keshavarz, M., Iravani, N., Zarei Ahmady, A., and
Vafaei-Nezhad, M., J. Chin. Chem. Soc., 2015, vol. 62,
p. 1079. doi 10.1002/jccs.201500329
8. Li, J., Yang, G., Qin, Y., Yang, X., and Cui, Y.,
Tetrahedron: Asymmetry, 2011, vol. 22, p. 613. doi
1
0.1016/j.tetasy.2011.03.016
38. Keshavarz, M., Iravani, N., Ahmadi Azghandi, M.H.,
and Nazari, S., Res. Chem. Intermed. 2016, vol. 42,
p. 4591. doi 10.1007/s11164-015-2302-0
1
9. Trindade, A.F., Gois, P.M.P., and Afonso, C.A.M.,
Chem. Rev., 2009, vol. 109, p. 418. doi 10.1021/
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 3 2017