(Carboxy-3-oxopropylamino)-3-propylsilylcellulose as a novel organocatalyst for the synthesis of substituted imidazoles under solvent-free conditions

Article abstract of DOI:10.1039/c5ra01909e

(Carboxy-3-oxopropylamino)-3-propylsilylcellulose (COPAPSC), a novel organocatalyst, has been prepared by a synthesis grafting of -COOH functionalized organosilanes on a cellulose using surface hydroxyl groups as anchor points. The -CO₂H group-functionalized cellulose was synthesized via the consecutive surface functionalization with 3-aminopropyltriethoxysilane (3-APTES) followed by the condensation of the surface -NH₂ groups with succinic anhydride. COPAPSC is used as a catalyst for the synthesis of tri- and tetra-substituted imidazoles from the reaction of benzil, aromatic aldehydes, ammonium acetate, and amines under solvent-free conditions. The key advantages of this process are high yields, easy work-up, purification of products by non-chromatographic methods and the reusability of the catalyst.

Full text of DOI:10.1039/c5ra01909e

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(Carboxy-3-oxopropylamino)-
3-propylsilylcellulose as a novel organocatalyst for
the synthesis of substituted imidazoles under
solvent-free conditions
Cite this: RSC Adv., 2015, 5, 33974
*
Mehri Salimi, Mohammad Ali Nasseri, Tayyebeh Daliran Chapesshloo
and Batol Zakerinasab
(Carboxy-3-oxopropylamino)-3-propylsilylcellulose (COPAPSC), a novel organocatalyst, has been prepared
by a synthesis grafting of –COOH functionalized organosilanes on a cellulose using surface hydroxyl groups
as anchor points. The –CO2H group-functionalized cellulose was synthesized via the consecutive surface
functionalization with 3-aminopropyltriethoxysilane (3-APTES) followed by the condensation of the
surface –NH2 groups with succinic anhydride. COPAPSC is used as a catalyst for the synthesis of tri- and
tetra-substituted imidazoles from the reaction of benzil, aromatic aldehydes, ammonium acetate, and
amines under solvent-free conditions. The key advantages of this process are high yields, easy work-up,
purification of products by non-chromatographic methods and the reusability of the catalyst.
Received 4th February 2015
Accepted 23rd March 2015
DOI: 10.1039/c5ra01909e
www.rsc.org/advances
sulfuric acid has been supported on cellulose and the acid
modied cellulose was used as an activated catalyst for the
Introduction
synthesis of a-amino amide derivatives through Ugi reactions,
synthesis of 1,4-dihydropyridines through Hantzsch reactions,
and synthesis of 3,4-dihydropyrimidin-2(1H)-ones/-thiones
through Biginelli reactions.11–13 In addition, carboxylate-
functionalized cellulose has been prepared by the reaction of
succinic anhydride and cellulose, and used as an effective bio-
sorbent for heavy metals remediation.14 Recently, cellulose has
gained renewed interest as a raw material and still possesses a
high potential for future applications. The imidazole nucleus is
a fertile source of biologically important molecules15 and is the
core structural skeleton in many important biological mole-
cules, such as histidine, histamine, and biotin, as well as several
drug moieties16,17 such as trifenagrel, eprosartan, and losartan.
In addition, they are used in photography as photosensitive
compounds. Some substituted triarylimidazoles are the selec-
tive antagonists of the glucagon receptors and inhibitors of IL-1
biosynthesis.18
The recent development of green chemistry and organome-
tallic chemistry expands the utility of imidazoles as ionic
liquids19–21 and N-heterocyclic carbenes.19,22,23 Radziszewski and
Japp24,25 proposed the rst synthesis of the imidazole core in
1882, starting from 1,2-dicarbonyl compounds, aldehydes, and
ammonia to obtain 2,4,5-triphenylimidazole.
From this discussion and our interest and experience in the
area of heterogeneous catalysis in organic synthesis,26–28 we
report a new surface –CO2H group functionalized cellulose via
the consecutive surface functionalization with 3-aminopropyl-
triethoxysilane (3-APTES) followed by the condensation of the
Nowadays, owing to the increasing concern about environ-
mental consciousness, more attention has been focused on the
development of new processes that minimize pollution and
maximize sustainable development in chemical synthesis.1
In this respect, the immobilization of catalysts on solid
supports has several important potential advantages such as
removal, recovery, and reutilization of catalysts; reduced envi-
ronmental contamination; good thermal and chemical stabili-
ties; and good dispersion of the active catalytic sites.2 For this
purpose, exploring heterogeneous catalysis is obviously on the
rise, especially in industries.3 Many solid materials as supports,
such as silica,4,42 zeolites,5 metal oxides,6 graphene,7 magnetic-
materials,8 and polymers,9 have broadly been investigated for
catalytic applications. A considerable stimulation of scientic
and technological research has been triggered since the past 10
years in response to the growing global importance of renew-
able resources and environmentally compatible materials.10 In
the eld of natural biopolymers, cellulose could especially be
utilized as a support for catalytic applications.
Cellulose is the most widely spread organic polymer that is
found in nature because it constitutes the main component of
the plants' cell wall. It is well-known that cellulose is a fasci-
nating, inexhaustible biopolymer and a renewable raw material.
It was widely applied as an efficient support and/or template for
the synthesis of inorganic and organic materials. For example,
Department of Chemistry, College of Sciences, Birjand University, Birjand 97175-615,
Iran. E-mail: msalimi@birjand.ac.ir
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surface –NH2 groups with succinic anhydride (Scheme 1).
Previously, –CO2H and –SO3H functionalized celluloses have
been reported but the incorporation of the –CO2H group on a
cellulose by condensation between an anhydride and a primary
amine has not been studied so far. On the contrary, the
increasing importance of metal-free catalysis motivated us to
use this organically modied acid functionalized cellulose
(COPAPSC) as a catalyst for the synthesis of imidazole from a
mixture of an aromatic aldehyde, an amine and a a-diketone. To
the best of our knowledge, organocatalysis promoted by a
–CO2H functionalized cellulose for the synthesis of imidazole
has not been explored so far.
Experimental
Fig. 1 FT-IR spectra of: (a) cellulose and (b) COPAPSC.
General
Chemicals were purchased from Merck and Fluka chemical
companies. IR spectra were obtained in KBr pellets in the
reection mode on an Avata Therma Nicolet FTIR instrument.
1H NMR spectra were obtained on a Bruker Avance DPX-250
MHz spectrometer using TMS as an internal standard and
CDCl3 or DMSO as the solvent. 13C NMR spectra were obtained
on a Bruker Avance DPX-62.5 MHz spectrometer (CDCl3 or
DMSO solution). Mass spectra were obtained on a GC 17A, MS
QP 5050 Shimadzu instrument. Elemental analysis for C, H, and
N were obtained using an Elementar, Vario EL III. All the
reactions were monitored by thin layer chromatography (TLC)
on pre-coated sheets of silica gel G/UV-254 using UV light for
visualization. Melting points were determined with an Electro-
thermal 9100 melting point apparatus.
Preparation of COPAPSC
A magnetically stirred cellulose (5.0 g) was suspended in dry
toluene (50 ml) and then an excess of 3-APTES (5.0 ml) was
added. The suspension was mechanically stirred as it was
heated under reux for 24 h under an Ar atmosphere. The
resulting white solid was ltered, washed repeatedly with
toluene, ethanol–water, deionized water and methanol and
nally dried under vacuum at 60 ꢀC for 4 h to give 3-amino-
propylsilylcellulose (3-APSC) (5.2 g). This 3-APSC functionalized
cellulose was stirred with 0.15 g (15 mmol) of succiniꢀc anhy-
dride dissolved in dry chloroform (20 ml) for 4 h at 50 C, and
the nal product was collected by ltration, washed sequentially
with chloroform, ethanol and diethyl ether. The product was
Scheme 1 Preparation of (carboxy-3-oxopropylamino)-3-propylsilylcellulose.
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Scheme 2 COPAPSC catalyzed synthesis of trisubstituted and tetrasubstituted imidazoles.
dried in a vacuum desiccator to give COPAPSC as a white ethanol to afford the pure products. The recovered catalyst was
powder (5.39 g).
dried and reused in the subsequent runs.
Results and discussion
Catalyst characterization
General procedure for the preparation of imidazole
derivatives
A
mixture of 1,2-diketone (1 mmol), aromatic aldehyde Fig. 1 shows the FT-IR spectra of cellulose and COPAPSC. The
(1 mmol), amine (1 mmol), ammonium acetate (1.5 mmol), and absorbance at 3200–3500 cmꢂ1 range can be attributed the O–H
COPAPSC (0.2 g equal to 0.05 mmol of H+) was stirred at 110 ꢀC and N–H amid stretching vibrations of COPAPSC. The two
under solvent-free conditions for the given time (Tables 2 and 3). bands at 2933 and 2898 cmꢂ1 are attributed to the –CH2–
Aer completion of the reaction, appropriate amounts of hot asymmetric and symmetric stretching vibrations, respectively.
EtOH (96%) was added and the mixture was stirred for 10 min The absorbance at 1728 and 1693 cmꢂ1 are due to the carbonyl
and then the catalyst was separated by ltration. The catalyst groups of acid and amide, respectively. Another band at
was washed with warm ethanol (3 ml ꢁ 3) to clean effectively. 1419 cmꢂ1 is attributed to the C–N stretching vibration, which
The ltrate was concentrated in vacuum to remove ethanol. The overlapped with the –C–C–H vibration of cellulose. The absor-
residue was washed with cold water and crystallized from hot bance at 1058 cmꢂ1 is assigned to the –C–O– stretching
Table 1 Effect of solvent, temperature and amount of catalyst on the synthesis of 4da
Entry
Catalyst (g)
Solvent
Temperature (ꢀC)
Time (h)
Yieldb (%)
1
2
3
4
5
6
7
8
Cellulose (0.2)
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Solvent free
Water
110
80
80
6
7
7
5
5
5
5
5
4
4
4
7
7
5.5
9
8
15
40
52
63
55
73
80
60
72
84
84
—
72
70
70
75
COPAPSC (0.08)
COPAPSC (0.10)
COPAPSC (0.20)
COPAPSC (0.08)
COPAPSC (0.10)
COPAPSC (0.20)
COPAPSC (0.08)
COPAPSC (0.10)
COPAPSC (0.2)
COPAPSC (0.3)
COPAPSC (0.20)
COPAPSC (0.20)
COPAPSC (0.20)
COPAPSC (0.20)
COPAPSC (0.20)
80
100
100
100
110
110
110
110
Reux
Reux
Reux
140
140
9
10
11
12
13
14
15
16
Methanol
Ethanol
Ethylene glycol
Glycerol
a
Reaction conditions: 4-chlorobenzaldehyde (1 mmol), ammonium acetate (1.5 mmol), and benzil (1 mmol) in the presence of cellulose and
COPAPSC. b Isolated yields.
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Table 2 Synthesis of 2,4,5-trisubstituted imidazolesa
Entry
R1
Product
Time (h)
MP ꢀC (lit.) [ref.]
Yieldb (%)
1
2
3
4
5
6
7
8
C6H5
4a
4b
4c
4d
4e
4f
4g
4h
4j
4
4
4
4
4
4
5
4
270–273 (274–276) 30
226–228 (228–230) 30
227–229 (232–234) 30
260–261 (260–262) 30
235–238 (234–236) 30
263–265 (>300) 31
230–233 (234–236) 30
207–210 (202–205) 31
244–246 (254–256) 30
228–230 (230–231) 31
256–259 (256–259) 31
77
85
82
84
82
78
77
79
88
80
75
4-OMeC6H4
4-MeC6H4
4-ClC6H4
4-NO2C6H4
3-NO2C6H4
4-OHC6H4
2-OHC6H4
4-BrC6H4
9
10
11
4
5.5
6
2-NO2C6H4
4-N(Me)2C6H4
4k
4l
a
Reactions were performed with benzil (1 mmol), aromatic aldehyde (1 mmol), ammonium acetate (1.5 mmol) and COPAPSC (0.2 g equal to 0.05
mmol H+) at 110 ꢀC under solvent-free conditions. b Isolated yields of pure products.
vibration.29 The OH vibration of the carboxylic groups over- compounds, the catalytic activity of the Bronsted acid COPAPSC
lapped with the OH vibration of cellulose.
was tested for the synthesis of 2,4,5-trisubstituted and
The nitrogen content in COPAPSC was determined to be 1,2,4,5-tetrasubstituted imidazoles under solvent-free condi-
0.32% (0/23 mmol gꢂ1) by elemental analysis. The number of H+ tions (Scheme 2).
sites of COPAPSC was determined to be 0.25 mmol gꢂ1 by an
We attempted to nd technically simple, high yielding, and
acid–base titration, which was very close to the nitrogen solvent-free conditions for the synthesis of these compounds.
content. These results indicated that most of the nitrogen Therefore, we studied COPAPSC as a catalyst in the cyclo-
species on the sample were in the form of amide groups.
condensation of benzil, aldehyde, ammonium acetate, and
In continuation of our work on the development of useful amine. Firstly, the reaction of 4-chlorobenzaldehyde (1 mmol),
synthetic methodologies toward the synthesis of heterocyclic ammonium acetate (1.5 mmol) and benzil (1 mmol) catalyzed
Table 3 Synthesis of 1,2,4,5-tetrasubstituted imidazolesa
Entry
R1
R2
Product
Time (h)
MP ꢀC (lit.) [ref.]
Yieldb (%)
1
2
3
4
5
6
7
8
C6H5
C6H5
Benzyl
Benzyl
4-MeC6H4
Benzyl
Benzyl
Benzyl
Benzyl
4-MeC6H4
Benzyl
6a
6b
6c
6d
6e
6f
6g
6h
6i
5.5
5
5
3.5
4
5
4
5
4
4.5
4
210–211 (214–216) 15
148–150 (144–146) 32
156–158 (160–162) 15
180–181 (176–178) 33
160–163 (162–164) 15
137–139 (140–141) 34
137–138 (134–135) 34
175–178 (170–172) 34
223–226 (219–220) 32
253–254 (257–259) 15
150–152 (149–151) 32
192–194 (188–191) 32
83
85
82
85
87
75
84
75
75
78
87
80
3-ClC6H4
4-ClC6H4
4-OMeC6H4
4-OMeC6H4
2-ClC6H4
4-OHC6H4
4-BrC6H4
4-NO2C6H4
4-OHC6H4
3-NO2C6H4
4-MeC6H4
9
10
11
12
6j
6k
6l
4-MeC6H4
4-MeC6H4
4
a
Reactions were performed with benzil (1.0 mmol), aromatic aldehyde (1.0 mmol), ammonium acetate (1.0 mmol), amine (1.0 mmol), and
COPAPSC (0.2 g equal to 0.05 mmol H+) at 110 ꢀC under solvent-free conditions. b Isolated yields of pure products.
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Scheme 3 Probable mechanism for the formation of 6a using COPAPSC as catalyst.
by COPAPSC was investigated in different solvents as well as
under solvent-free conditions, and the results are shown in turned our attention to study the scope of this method. We
Table 1. applied this catalyst for the synthesis of trisubstituted and tet-
Aer determining the optimum reaction conditions, we
Initial screening studies conrmed that the solvent-free rasubstituted imidazoles using different aromatic aldehydes
technique is the optimal condition for this reaction. Another with a wide range of substitutions under solvent-free heating
important point which could be elicited evidently from these conditions to establish the catalytic importance of COPAPSC for
results is that raising the reaction temperature from 80 ꢀC to this reaction. The corresponding results are given in Tables 2
110 ꢀC and the amount of catalyst from 0.08 g to 0.2 g increased and 3.
the yield and also improved the reaction rates (Table 1, entries
The proposed mechanism for the formation of the products
2–10). A further increase in the catalyst loading does not affect can be explained by the pathway presented in Scheme 2. The
the yield (Table 1, entry 11). Moreover, it is worth mentioning reaction commenced through the acid catalyzed formation of
that application of solvents, such as H2O, EtOH, CH3OH, imine (7), which underwent nucleophilic attack by aniline to
ethylene glycol, and glycerol, did not lead to better results.
Under these conditions, longer reaction times and lower yields
can be observed clearly (Table 1, entries 12–16). On the contrary,
due to the growing concern for the inuence of the organic
solvents on the environment as well as on the human body,
organic reactions without the use of conventional organic
solvents have attracted the attention of synthetic organic
chemists. It is observed that the solvent-free conditions gave an
excellent yield of product and shorter reaction times than that
of in the presence of solvents. The development of solvent-free
organic reactions is thus gaining prominence.
As a control experiment, the cyclocondensation of benzil,
aldehyde, and ammonium acetate was also carried out at 110 ꢀC
in the presence cellulose for 6 hour under solvent-free condi-
tions, which resulted in a yield of 15% (Table 1, entry 1).
Fig. 2 Reusability of COPAPSC in condensation of benzaldehyde,
ammonium acetate, aniline and benzyl at 110 ꢀC under solvent-free
conditions in 5 h.
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Table 4 Comparison of results using COPAPSC with results obtained by other works for the synthesis of 4d
Entry
Catalyst
Condition
Yield (%)
Ref.
1
2
3
4
5
6
7
8
9
COPAPSC
Yb(OPf)3
Acetic acid
InCl3$3H2O
Diethyl bromophosphate
DABCO
CSC-Star-SO3AlCl2
L-Proline
Solvent free, 110 ꢀC, 4 h
HOAc, C10F18, 80 ꢀC, 6 h
Chloroform, 160, MWI, 15 min
MeOH, r.t., 9.4 h
84
83
90
71
95
92
94
88
82
—
35
36
37
38
39
40
31
41
CH3CN, ultrason., 30 min
t-BuOH, 65 ꢀC, 12 h
EtOH, 80 ꢀC, 10 h
MeOH, 60 ꢀC, 9 h
MCM-41
Reux in AcOH, 32 min
give the in situ intermediate (8). An acid catalyzed condensation (250 MHz, DMSO-d6) (d, ppm): 2.34 (s, 3H), 7.45–6.94 (m, 14H),
between this intermediate (8) and diketone (1) produced 7.50 (t, 1H), 8.11 (d, J ¼ 7.8 Hz, 1H), 8.24 (d, J ¼ 7.5 Hz, 1H), 8.52
another in situ intermediate (9), which on subsequent aroma- (s, 1H); 13C NMR (62.9 MHz, DMSO-d6) (d, ppm): 21.2, 122.7,
tization produces the tetrasubstituted imidazole (6a) and 123.4, 126.9, 127.3, 127.9, 128.2, 128.8, 129.1, 131.0, 132.0,
releases the catalyst for the next catalytic cycle (Scheme 3).15
The recyclability of the catalyst was also examined. To this
132.2, 133.7, 134.3, 138.7, 139.1, 144.3, 148.0; anal. calcd for
28H21N3O2: C, 77.94; H, 4.91; N, 9.74. Found: C, 77.89; H, 4.97;
C
end, the catalyst that was recovered from the reaction between N, 9.78.
benzil, aniline, benzaldehyde, and ammonium acetate by
ltration was washed three times with warm ethanol and dried
ꢀ
at 80 C for a period of 5 h in a vacuum oven. The recovered
Acknowledgements
catalyst can be reused four times in subsequent reactions
without any signicant loss in its activity. The results with the
recyclable COPAPSC are summarized in Fig. 2.
We are thankful to the University of Birjand Research Council
for supporting this study.
In Table 4, the efficiency of our method for the synthesis of
imidazoles is compared with some other published works in
literature. The reaction of 4-chloro benzaldehyde, benzil, and
ammonium acetate was used as a model reaction. Each of these
methods have their own advantages, but they oen suffer from
some troubles, including the use of organic solvent, (entries
2–5) and long reaction time (entries 6–9).
In summary, COPAPSC, an efficient, reusable, green and
solidly supportive biodegradable acid catalyst, has been
prepared and utilized for the synthesis of imidazole derivatives
Notes and references
1 V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara and
J. M. Basset, Chem. Rev., 2011, 111, 3036–3075.
´
2 S. E. Garcıa-Garrido, J. Francos, V. Cadierno, J. M. Basset and
V. Polshettiwar, ChemSusChem, 2011, 4, 104–111.
3 (a) H. U. Blaser, A. Baiker and R. Prins, Heterogeneous
catalysis and ne chemicals IV, Elsevier, Netherlands, 1997;
(b) J. M. Thomas and W. J. Thomas, Principles and practice
of heterogeneous catalysis, VCH, Weinheim, 1997.
4 N. Audic, H. Clavier, M. Mauduit and J. C. Guillemin, J. Am.
Chem. Soc., 2003, 125, 9248–9249.
5 (a) L. J. Gu, D. Ma, S. D. Yao, C. L. Wang, W. J. Shen and
X. H. Bao, Chem. Commun., 2010, 46, 1733–1735; (b)
M. Iwasaki and H. Shinjoh, Chem. Commun., 2011, 47,
3966–3968.
6 E. Ortel, S. Sokolov, C. Zielke, L. Lauermann, S. Selve,
K. Weh, B. Paul, J. Polte and R. Kraehnert, Chem. Mater.,
2012, 24, 3828–3838.
7 M. Yang, M. Zhou, A. H. Zhang and C. Zhang, J. Phys. Chem.
C, 2012, 116, 22336–22340.
by
a one-pot coupling reaction of benzil, benzaldehyde
compounds, ammonium acetate, and primary amine. More-
over, the broad scope, operational simplicity, and practicability
render it as an attractive approach for the generation of
different compounds with potential properties for use in
medicinal chemistry programs.
Selected experimental data
2-(4-Methoxyphenyl)-4,5-diphenyl-1H-imidazole (4b). White
solid, (85%, 0.277 g) mp: 231–233 ꢀC (Lit.30 mp 228–230 ꢀC). IR
(KBr, n: cmꢂ1): 3425, 3029, 2956, 1610, 1495, 1249; 1H NMR (250
MHz, DMSO-d6) (d, ppm): 3.79 (s, 3H), 7.05 (d, J ¼ 8.4 Hz, 2H),
7.50–7.28 (m, 10H), 8.03 (d, J ¼ 8.1 Hz, 2H), 12.50 (s, 1H); 13C
NMR (62.9 MHz, DMSO-d6) (d, ppm): 55.2, 114.1, 123.5, 126.8,
127.7, 128.4, 129, 131.6, 135.7, 137.2, 146.1, 159.8; anal. calcd
for C22H18N2O: C, 80.96; H, 5.56; N, 8.58. Found: C, 80.90; H,
5.51; N, 8.63.
8 R. B. N. Baig and R. S. Varma, Chem. Commun., 2012, 48,
2582–2584.
9 R. B. N. Baig and R. S. Varma, Green Chem., 2013, 15, 1839–
1843.
10 D. Klemm, B. Heublein, H. P. Fink and A. Bohn, Angew.
Chem., Int. Ed., 2005, 44, 3358–3393.
1-(4-Methylphenyl)-2-(3-nitrophenyl)-4,5-diphenyl-1H-imid-
azole (6k). Yellow solid, (87%, 0.375 g) mp: 150–152 C (Lit.33 11 H. Mofakham, Z. Hezarkhani and A. Shaabani, J. Mol. Catal.
ꢀ
149–151 ꢀC). IR (KBr, n: cmꢂ1): 3052, 1596, 1525, 1350; 1H NMR
A: Chem., 2012, 360, 26–34.
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RSC Adv., 2015, 5, 33974–33980 | 33979

View Article Online
RSC Advances
Paper
12 J. Safari, S. Hossein Banitaba and S. D. Khalili, J. Mol. Catal. 28 M. A. Nasseri, M. Salimi and A. A. Esmaeili, RSC Adv., 2014,
A: Chem., 2011, 335, 46–50. 4, 61193–61199.
13 A. Rajack, K. Yuvarajua, C. h. Praveen and Y. L. N. Murthy, J. 29 W. Chen, L. Zhong, X. Peng, J. Lin and R. Sun, Cellulose,
Mol. Catal. A: Chem., 2013, 370, 197–204. 2014, 21, 125–137.
14 W. Zhang, C. Li, M. Liang, Y. Geng and C. Lu, J. Hazard. 30 A. Teimouri and A. Naja Chermahini, J. Mol. Catal. A:
Mater., 2010, 18, 468–473. Chem., 2011, 346, 39–45.
15 A. Mohammadi, H. Keshvari, R. Sandaroos, B. Maleki, 31 S. Samai, G. C. Nandi, P. Singh and M. S. Singh, Tetrahedron,
H. Rouhi, H. Moradi, Z. Sepehr and S. Damavandi, Appl.
Catal., A, 2012, 429–430, 73–78.
2009, 65, 10155–10161.
32 A. R. Karimi, Z.
Alimohammadi,
J.
Azizian,
16 K. Ramesh, S. Narayana Murthy, K. Karnakar,
Y. V. D. Nageswar, K. Vijayalakhshmi, B. L. A. Prabhavathi
A. A. Mohammadi and M. R. Mohammadizadeh, Catal.
Commun., 2006, 7, 728–732.
Devi and R. B. N. Prasad, Tetrahedron Lett., 2012, 53, 1126– 33 S. Ray, P. Das, A. Bhaumik, A. Dutta and C. Mukhopadhyay,
1129. Appl. Catal., A, 2013, 458, 183–195.
17 C. Leister, Y. Wang, Z. Zhao and C. W. Lindsley, Org. Lett., 34 S. Kantevari, S. V. N. Vuppalapati, D. O. Biradar and
2004, 6, 1453–1456. L. Nagarapu, J. Mol. Catal. A: Chem., 2007, 266, 109–113.
18 L. S. Gadekar, S. R. Mane, S. S. Katkar, B. R. Arbad and 35 M.-G. Shen, C. Cai and W.-B. Yi, J. Fluorine Chem., 2008, 129,
M. K. Lande, Cent. Eur. J. Chem., 2009, 7, 550–554. 541–544.
19 S. Samai, G. C. Nandi, P. Singh and M. S. Singh, Tetrahedron, 36 E. Gelens, F. J. J. De Kanter, R. F. Schmitz,
2009, 65, 10155–10161.
20 J. Dupont, R. F. de Souza and P. A. Z. Suarez, Chem. Rev.,
2002, 102, 3667–3692.
21 S. Chowdhury, R. S. Mohan and J. L. Scott, Tetrahedron, 2007,
63, 2363–2389.
22 D. Bourissou, O. Guerret, F. P. Gabbai and G. Bertrand,
Chem. Rev., 2000, 100, 39–92.
23 P. L. Arnold and S. T. Liddle, Chem. Commun., 2006, 69,
3959–3971.
24 B. Radziszewski, Chem. Ber., 1882, 15, 1493–1496.
25 F. Japp and H. Robinson, Chem. Ber., 1882, 15, 1268–1270.
26 M. A. Nasseri, A. Mohammadinezhad, M. Salimi and J. Iran,
Chem. Soc., 2015, 12, 81–86.
L. A. J. M. Sliedregt, B. J. Van Steen, C. G. Kruse, R. Leurs,
M. B. Groen and R. V. A. Orru, Mol. Diversity, 2006, 10, 17.
37 L. Nagarapu, S. Apuri, S. Kantevari and J. Mol, J. Mol. Catal.
A: Chem., 2007, 266, 104–108.
38 D. Nagargoj, P. Mandhane, S. Shingote, P. Badadhe and
C. Gill, Ultrason. Sonochem., 2012, 19, 94–96.
39 S. Narayana Murthy, B. Madhav and Y. V. D. Nageswar,
Tetrahedron Lett., 2010, 51, 5252–5257.
40 P. Gupta and S. Paul, J. Mol. Catal. A: Chem., 2012, 352, 75–
80.
41 R. Hekmat Shoar, G. Rahimzadeh, F. Derikvand and
M. Farzaneh, Synth. Commun., 2010, 40, 1270–1275.
42 M. Nandi, J. Mondal, K. Sarkar, Y. Yamauchi and
A. Bhaumik, Chem. Commun., 2011, 47, 6677–6679.
27 A. Mohammadinezhad, M. A. Nasseri and M. Salimi, RSC
Adv., 2014, 4, 39870–39874.
33980 | RSC Adv., 2015, 5, 33974–33980
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