Synthesis of a novel DABCO-based nanomagnetic catalyst with sulfonic acid tags: application to the synthesis of diverse spiropyrans

Article abstract of DOI:10.1007/s11164-018-3421-1

Abstract: In this paper, sulfonic acid functionalized 1,4-diazabicyclo[2.2.2]octane (DABCO)-based magnetic nanoparticle Fe₃O₄ [Fe₃O₄@SiO₂@Pr-DABCO-SO₃H]Cl₂ was synthesized and fu

Full text of DOI:10.1007/s11164-018-3421-1

Res Chem Intermed
https://doi.org/10.1007/s11164-018-3421-1
Synthesis of a novel DABCO-based nanomagnetic
catalyst with sulfonic acid tags: application
to the synthesis of diverse spiropyrans
1
1
1
Mostafa Rajabi-Salek
•
Mohammad Ali Zolfigol
•
Mahmoud Zarei
Received: 4 January 2018 / Accepted: 27 March 2018
Ó Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract In this paper, sulfonic acid functionalized 1,4-diazabicyclo[2.2.2]octane
DABCO)-based magnetic nanoparticle Fe O [Fe O @SiO @Pr-DABCO-SO H]Cl
2
(
3
4
3
4
2
3
was synthesized and fully characterized using various techniques. Then the catalyst was
examined for the convenient synthesis of spiropyran derivatives, resulting in high
reaction yields, short reaction times, and the recovery and reusability of the catalyst.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11164-
018-3421-1) contains supplementary material, which is available to authorized users.
&
&
1
Mohammad Ali Zolfigol
zolfi@basu.ac.ir; mzolfigol@yahoo.com
Mahmoud Zarei
mahmoud8103@yahoo.com
Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University,
Hamedan 6517838683, Iran
123

M. Rajabi-Salek et al.
Graphical Abstract
Keywords Sulfonic acid
Á
1,4-Diazabicyclo[2.2.2]octane (DABCO)
Á
[
derivatives
Fe O @SiO @(CH ) -DABCO-SO H]Cl Á Recyclable nanocatalyst Á Spiropyran
3
4
2
2 3
3
2
Introduction
Spiro compounds can be found in many naturally occurring substances. Likewise,
the indole moiety is ubiquitous and combining the two structures can raise
biological activity significantly. For example, the cytostatic alkaloids, the
spirotryprostatins and pteropodines, can be noted as examples of spiroindoles
[1–13]. Condensed spirooxindoles containing a condensed 4H-pyran provide
pharmacologically active systems with diuretic, spasmolitic, anti-coagulant, anti-
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
cancer, and anti-naphylactic activities [14]. Recently, the chemistry of spirooxin-
doles was extensively reviewed [15]. Furthermore, nitrile substituted 4H-pyrans
have been identified as candidates to combat neurodegenerative disorders [16, 17].
The utility of nano-magnetic catalysts is well-recognized due to the ease of work-up
and catalyst recovery with such systems [18–25]. Generally, the desired catalytic
active sites are immobilized on nanomagnetic Fe O via coordinate or covalent
3
4
bonds. Fe O , Fe O @C and Fe O @silica are examples of nanoparticles
4
3
4
3
3 4
functionalized with SO H groups, which have been used for various purposes
3
[
26, 27]. Recently, magnetic nanoparticles (MNPs) and mesoporous silica SBA-15
with 1,4-diazabicyclo[2.2.2]octane (DABCO) tags were also applied in organic
methods [28, 29]. In a continuation of our previous work into developing of new
categories of supported ionic liquids and molten salts based on nanomagnetic Fe O
3
4
such as silica [nano-Fe O @SiO @(CH ) -Imidazole-SO H]Cl and 1,4-diaza-
3
3
4
2
2 3
bicyclo[2.2.2]octane-sulfonic acid chloride (SBDBSAC) [30, 31], herein we
decided to profit from our previous experience to design and synthesis [Fe O @
SiO @Pr-DABCO-SO H]Cl as an efficient nanomagnetic catalyst to be applied in
3
4
2
3
2
the synthesis of spiropyran derivatives (Scheme 1).
Experimental
General information
All of the chemicals were purchased from Merck Chemical Company. The known
products were identified by comparison of their melting points and spectral data
with those reported in the literature. Progress of the reactions was monitored by
TLC using silica gel SIL G/UV 254 plates. Melting points were recorded on a B u¨ chi
B-545 apparatus in open capillary tubes. Fourier transforms infrared (FTIR) spectra
of derivatives and catalyst were recorded on a FTIR spectrometer (Perkin-Elmer
1
spectrum 65 or JASCO FT/IR4100LE) using KBr disks. The H NMR (400 MHz)
3 4 2 3 2
Scheme 1 Synthesis of spiropyran derivatives using [Fe O @SiO @Pr-DABCO-SO H]Cl
123

M. Rajabi-Salek et al.
1
3
and C NMR (100 MHz) experiments were run on BRUKER BioSpin GmbH
spectrometers (d in ppm). Transmission electron microscopy (TEM) images were
performed using a Zeiss-EM10C-100 microscope. Scanning electron microscopy
(
SEM), (EDX) and elemental mapping studies were performed using a SIGMA VP-
00, VSM model LBKFB. Powder X-ray diffraction (XRD) patterns were recorded
by an Ital structure ADD2000 model, using a monochromatized Cu Ka
k = 0.154 nm) X-ray source in the range 2° \ 2h \ 90°. Thermogravimetric
analyses were carried out on a METTLER TOLEDO apparatus (models Pyris 1)
5
(
-
1
under nitrogen atmosphere at 25 °C and using a heating rate of 20 °C min up to
00 °C.
7
Preparation of [Fe O @SiO @Pr-DABCO-SO H]Cl
2
3
4
2
3
Magnetic nanoparticles of Fe O4, Fe O @SiO and Fe O @SiO @PrCl were
2
3
3
4
2
3
4
prepared by previously reported literature [24]. Then, 1,4-diazabicyclo[2.2.2]octane
(
0.491 g, 7 mmol) in dry toluene (50 mL) was added to the Fe O @SiO @PrCl
3 4 2
(
using an external magnet, washed and dried accordingly to obtain [Fe O @SiO @
1 g) and the mixture was heated to reflux for 12 h. The solid obtained was isolated
3
4
2
Pr-DABCO]Cl. Finally, a solution of chlorosulfonic acid (0.456 mL, 1.165 g,
mmol) in dry dichloromethane (10 mL) was added drop-wise to the {Fe O @
SiO @Pr-DABCO}, the reaction mixture was stirred for 6 h, isolated using an
7
3
4
2
external magnet and washed with dichloromethane to give [Fe O @SiO @Pr-
3
4
2
DABCO-SO H]Cl (Scheme 2).
2
3
General procedure for the synthesis of spiropyran derivatives
In a 25 mL round-bottomed flask, a mixture of isatin (1 mmol, 0.147 g),
malononitrile (1 mmol, 0.066 g), 1,3-dicarbonyl compound (1 mmol), [Fe O @
SiO @Pr-DABCO-SO H]Cl (0.02 g) and H O (10 mL) were added a fitted reflux
3
4
2
3
2
2
condenser. The mixture was heated to reflux and, after completion of the reaction
monitoring by TLC), the mixture was allowed to cool to room temperature, and the
(
solvent was removed under vacuum. Then, the resultant solid mixture was extracted
with acetone (10 mL), and the catalyst was recovered using an external magnet. The
obtained pure products were washed with water/ethanol (Scheme 1).
Result and discussion
At the outset, we chose to synthesise heterogeneous nanomagnetic [Fe O @
3
4
SiO @Pr-DABCO-SO H]Cl . Magnetic nanoparticles of Fe O , Fe O @SiO and
2
2
3
2
3
4
3
4
Fe O @SiO @PrCl were synthesized according to the previously reported proce-
3
4
2
dure [24]. Then, 1,4-diazabicyclo[2.2.2]octane was added to the Fe O @SiO @
2
3
4
PrCl and nanomagnetic [Fe O @SiO @Pr-DABCO]Cl was isolated. In the next
3
4
2
step, a solution of chlorosulfonic acid in dry dichloromethane was added drop-wise
to the suspension of {Fe O @SiO @Pr-DABCO}, the reaction mixture filtered, and
the precipitate was washed with dichloromethane to give the desired
3
4
2
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
3 4 2 3 2
Scheme 2 Schematic preparation route of [Fe O @SiO @Pr-DABCO-SO H]Cl
[
Fe O @SiO @Pr-DABCO-SO H]Cl . This material was characterized using FT-
3 4 2 3 2
IR, X-ray diffraction patterns (XRD), SEM with elemental mapping and EDX,
TEM, TG/DTG and VSM.
In the FT-IR spectrum of [Fe O @SiO @Pr-DABCO-SO H]Cl , a broad band at
3
4
2
3
2
-
1
2
600–3500 cm was assigned to the OH stretching frequency of the SO H group
3
-
1
[32, 33]. The observation of a broad band at 1094–1222 cm
-
presence of SiO bands and two peaks at 1087 and 1206 cm corresponded to the
indicated the
1
2
vibrational modes of N–SO and O–SO bonds overlapped with SiO bands (Fig. 1).
2
2
2
The particle size and shape as well as the morphology of [Fe O @SiO @Pr-
3
4
2
DABCO-SO H]Cl as examined by XRD, SEM, SEM-elemental mapping, EDX
3
2
and TEM are shown in Figs. 2, 3, 4, 5, and 6 and Table 1. The X-ray diffraction
profile of [Fe O @SiO @Pr-DABCO-SO H]Cl was screened in a domain of 2° to
3
4
2
3
2
9
0°. The crystallite size was calculated using the Debye–Sherrer formula D = Kk/
(
ßCosh) [34] and was found to be in the range 14–81 nm (Table 1 and Fig. 2),
which is in a close agreement with the scanning electron microscopy results (SEM)
Fig. 3).
(
123

M. Rajabi-Salek et al.
Cl
Cl
N
N
O
O
Si
SO
3
H
EtO
Cl
N
N
O
O
Si
EtO
3 4 2 3 2
Fig. 1 FT-IR spectra of [Fe O @SiO @Pr-DABCO-SO H]Cl compared with steps of intermediate III
Fig. 2 XRD pattern of [Fe
3
O
4
@SiO @Pr-DABCO-SO
2
3
H]Cl
2
Table 1 XRD data for [Fe
3
O
4
@SiO @Pr-DABCO-SO
2
3
H]Cl
2
Entry
2h
9.1
Peak width (°)
Size (nm)
Inter planar distance (nm)
1
2
3
4
5
6
7
0.4
0.1
0.2
0.7
0.2
0.3
0.4
13.8
24.3
28.7
81.1
32.1
30.1
23.7
0.98
0.12
0.19
0. 98
0.12
0.16
0.14
18.3
30.1
35.8
43.0
57.2
63.3
Using SEM elemental mapping and EDX, the presence of C, N, O, Fe, S, Si and Cl
with a good distribution over the catalyst surface was also verified (Figs. 4 and 5).
TEM analysis (Fig. 6) indicated well-dispersed nanospherical particles with an
average size of 60 nm. Magnetic measurements showed that saturation of the catalyst
-
1
dropped to 27.6 emu g for [Fe O @SiO @Pr-DABCO-SO H]Cl compared to
3
4
2
3
2
-
Fe O at 68.8 emu g (Fig. 7).
1
3
4
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
3 4 2 3 2
Fig. 3 SEM of [Fe O @SiO @Pr-DABCO-SO H]Cl
Thermal gravimetric analysis and differential thermal gravimetric profiles are
presented in Fig. 8. In the TGA, the first weight loss step, relating to the loss of
surface-adsorbed water and organic solvents, takes place between 25 and 105 °C
and involves a weight loss of 3%. Finally, the second and main weight loss between
105 and 500 °C can be ascribed to the continuous decomposition of the organic
components (Fig. 8).
After approving the structure of described catalyst, we decided to study its
catalytic activity in the synthesis of spiropyran derivatives. For initial screening of
the catalytic applications, a multicomponent reaction between 1 mmol of isatin,
malononitrile and barbituric acid was considered as a model reaction (Table 2).
Low yield was obtained in the absence of catalyst under refluxing water conditions
(
solvent optimization, the model reaction was carried out using H O, CHCl , EtOH,
Table 2, entry 1). The optimal catalyst loading was (0.02 g) (Table 2, entry 5). For
2
3
EtOAc, Toluene and CH CN under reflux conditions. As summarized in Table 2
3
(entries 11–16), applying the refluxing water conditions afforded better yields and
reaction times than other reactions media.
Aiming to extend the scope and generality of the described protocol, after
optimization of the reaction conditions, a series of isatins was reacted with
123

M. Rajabi-Salek et al.
Fig. 4 SEM-elemental mapping of Fe, O, S, Cl, N Si and C atoms for [Fe
SO H]Cl
3 4 2
O @SiO @Pr-DABCO-
3
2
malononitrile, 1,3-dicarbonyl compounds, hydrazine, ethyl benzoylacetate and ethyl
acetoacetate under the optimized conditions. The results are presented in Table 3.
All reactions proceeded efficiently to give the desired spiropyran derivatives in good
to excellent yields and in short reaction times.
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
O Kα
13000
12000
11000
10000
FeKα
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
S Kα
SiKα
N Kα
S Kβ
FeLα
ClKβ
ClKα
FeKβ
C Kα
keV
10.00
0
3 4 2 3 2
Fig. 5 EDX of [Fe O @SiO @Pr-DABCO-SO H]Cl
Fig. 6 TEM of
[Fe
SO
3
O
H]Cl
4
@SiO
2
@Pr-DABCO-
3
2
123

M. Rajabi-Salek et al.
Fig. 7 VSM of a Fe
3
O
4
(red) and b [Fe
3
O
4
@SiO
2
@Pr-DABCO-SO
3
H]Cl
2
(blue). (Color figure online)
30.00
20.00
10.00
1
.000
0.000
95.00
-1.000
-2.000
90.00
0.00
-3.000
-10.00
8
5.00
0.00
-4.000
-20.00
-5.000
8
-30.00
100.0
200.0
300.0
400.0
500.0
Temp Cel
3 4 2 3 2
Fig. 8 Differential thermal analysis (TG/DTA) of [Fe O @SiO @Pr-DABCO-SO H]Cl
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
Table 2 The optimization of catalyst loading, temperature and various solvents (10 ml) in the synthesis
of spiropyrans
a
Yield (%)
Entry
Amount of catalyst (g)
Solvent
Temp. (°C)
Time (min)
1
2
3
4
5
6
7
8
9
_
H
H
H
H
H
H
H
H
H
H
2
2
2
2
2
2
2
2
2
2
O
O
O
O
O
O
O
O
O
O
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
rt
400
110
80
33
62
75
80
95
95
95
65
87
91
90
80
60
20
10
N.R
N.R
0.005
0.01
0.015
0.02
0.025
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
50
30
35
35
140
40
40
1
1
1
1
1
1
1
1
a
0
1
2
3
4
5
6
6
70
38
EtOH
CHCl
Reflux
Reflux
Reflux
Reflux
Reflux
100
40
3
100
60
EtOAc
Toluene
70
CH CN
3
60
–
60
–
100
60
Isolated yield
A plausible mechanism for the reaction is indicated in Scheme 3. Initially, the
carbonyl group of isatin is activated by the acidic moiety of [Fe O @SiO @Pr-
DABCO-SO H]Cl (i.e., SO H), suffers a Knoevenagel condensation with the
3
4
2
3
2
3
activated malononitrile compound, which was followed by removing one molecule
of H O to give intermediate I. 1,3-Dicarbonyl compounds (B) is converted to enol
2
form after tautomerisation and attached to cyanoolefin compound (I), as a Michael
acceptor, to give II. Finally, there was a cyclocondensation reaction of II prepared
III, which is converted to the corresponding product via tautomerization.
The recyclability and reuse of the catalyst was also studied in the model reaction.
As indicated in Fig. 9, [Fe O @SiO @Pr-DABCO-SO H]Cl was successfully
3
4
2
3
2
recycled and efficiently reused for up to eight reaction cycles with only a moderate
decrease in its catalytic activity. The acidic content of [Fe O @SiO @Pr-DABCO-
SO H]Cl was determined by titration against aqueous NaOH [42].
3
4
2
3
2
123

M. Rajabi-Salek et al.
3 4 2 3 2
Table 3 The preparation of spiropyran derivatives using [Fe O @SiO @Pr-DABCO-SO H]Cl as a
novel nano magnetic catalyst in water and under reflux conditions
[
time: 30 min, Yield:
[time: 35 min, Yield:
[
time: 30 min, Yield:
[
time: 30 min, Yield:
9
5%], white solid, M.p
95%], yellow solid, M.p
9
5%], brown solid, M.p
(
˚C): 268-270 [
35]
[35]
91%], yellow solid, M.p
[36]
(˚C): 212-214
[39]
(˚C): 232-234
(
˚C): 276-278
[
time: 37 min, Yield:
6%] yellow solid,36]M.p
˚C): 264-266[
[time: 30 min, Yield:
95%] brown solid, M.p
(˚C): 268-270
[time: 36 min, Yield:
[time: 37 min, Yield:
9
98%] brown solid, M.p
93%], yellow solid, M.p
[36]
[36]
(
(˚C): 252-254
(˚C): 239-242
[
time: 45 min, Yield:
[
time: 45 min, Yield:
4%], brown solid, M.p
˚C): >300
[time: 44 min, Yield:
[
time: 55 min, Yield:
9
5%], brown solid, M.p
9
88%], orange solid, M.p
9
1%], white solid, M.p
(
[9]
(˚C): >300 [
40]
(˚C): >300
(˚C): 278-280
[
time: 30 min, Yield:
[time: 30 min, Yield:
[
time: 28 min, Yield:
[
time: 50 min, Yield:
9
5%], orange solid, M.p
9
3%], orange solid, M.p
96%], yellow solid, M.p
9
4%], yellow solid, M.p
[38]
˚C): >300 [
11]
(˚C): 286-288 [37]
(˚C): 318-320
[
38]
(˚C): 326-328
(
[
time: 35 min, Yield:
[
time: 30 min, Yield:
[time: 40 min, Yield:
91%], brown solid,
[time: 30 min, Yield:
9
0%], orange solid, M.p
9
4%], brown solid, M.p
97%], orange solid, M.p
[
41]
(
˚C): 318-320 [
41]
(˚C): 260-262
M.p (˚C): 276-278
[38]
(˚C): 283-285
[11]
[
time: 45 min, Yield:
2%] brown solid, M.p
˚C): >300
[time: 40 min, Yield:
91%], brown solid,
M.p (˚C): 214-216
[
time: 25 min, Yield:
6%] yellow solid, M.p
˚C): 273-275
9
9
(
(
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
Scheme 3 The proposed mechanism for the synthesis of spiropyrans
3 4 2 3 2
Fig. 9 Recyclability of [Fe O @SiO @Pr-DABCO-SO H]Cl
123

M. Rajabi-Salek et al.
Conclusion
In conclusion, a convenient procedure is presented for the synthesis of spiropyran
derivatives in the presence of [Fe O @SiO @Pr-DABCO-SO H]Cl as a novel
3
4
2
3
2
nanomagnetic catalyst in refluxing water. The catalyst was fully characterized by
FT-IR, XRD, TEM, SEM-elemental mapping, EDX, TG/DTG and VSM. High yield
of products, short reaction time, facile workup and reusability of the catalyst are
major advantages of the described work.
Acknowledgements We thank Bu-Ali Sina University, National Elites Foundation and the Iran National
Science Foundation (INSF) (Grant Number: 940124) for financial support of our research groups.
References
1
2
3
4
5
6
7
. M. Shiri, Chem. Rev. 3508, 112 (2012)
. W. Francke, W. Kitching, Curr. Org. Chem. 233, 5 (2001)
. S. Rosenberg, R. Leino, Synthesis 2651, 262 (2009)
. R.M. Williams, R.J. Cox, Acc. Chem. Res. 127, 36 (2003)
. D. Silva, J.F.M. Garden, S.J. Pinto, J. Braz. Chem. Soc. 12, 273 (2001)
. C. Marti, E.M. Carreira, Eur. J. Org. Chem. 2209, 63 (2003)
. A.B. Dounay, K. Hatanaka, J.J. Kodanko, M. Oestreich, L.E. Overman, L.A. Pfeifer, M.M. Weis, J.
Am. Chem. Soc. 6261, 125 (2003)
8. A. Khalafi-Nezhad, E. Shaikhi Shahidzadeh, S. Sarikhani, F. Panahi, J. Mol. Catal. A. Chem. 379, 1
(2013)
9. G. Rui-Yun, A. Zhi-Min, M. Li-Ping, W. Rui-Zhi, L. Hong-Xia, W. Shu-Xia, Z. Zhan-Hui, ACS
Comb. Sci. 557, 15 (2013)
1
0. S. Ahadi, Z. Yasaei, A. Bazgir, J. Heterocyclic Chem. 1090, 47 (2010)
1. A.R. Moosavi-Zare, M.A. Zolfigol, E. Noroozizadeh, M. Zarei, R. Karamian, M. Asadbegy, J. Mol.
Catal. A: Chem. 217, 425 (2016)
1
12. D.S. Raghuvanshi, K.N. Singh, J. Heterocyclic Chem. 1323, 47 (2010)
13. P.S. Satasia, P.N. Kalaria, J.R. Avalani, D.K. Raval, Tetrahedron 5763, 70 (2014)
14. W.P. Smith, L.S. Sollis, D.P. Howes, C.P. Cherry, D.I. Starkey, N.K. Cobley, J. Med. Chem. 787, 41
(1998)
1
1
1
1
1
2
5. L.J. Yan, Y.C. Wang, Chemistry Select. 6948, 1 (2016)
6. L. Bonsignore, G. Loy, D. Secci, A. Calignano, Eur. J. Med. Chem. 515, 28 (1993)
7. L. Andreani, E. Lapi, Bol. Chim. Farm. 583, 99 (1960)
8. T. Cheng, D. Zhang, H. Li, G. Liu, Green Chem. 3401, 16 (2014)
9. R. Mrowczynski, A. Nan, J. Liebscher, RSC Adv. 5927, 4 (2014)
0. M.A. Zolfigol, V. Khakyzadeh, A.R. Moosavi-Zare, A. Rostami, A. Zare, N. Iranpoor, M.H. Beyzavi,
R. Luque, Green Chem. 2132, 15 (2013)
2
1. D. Zhang, C. Zhou, Z. Sun, L.-Z. Wu, C.-H. Tung, T. Zhang, Nanoscale 6244, 4 (2012)
2. V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara, J.-M. Basset, Chem. Rev. 3036, 111
2
(2011)
2
2
3. K. Debnath, K. Singha, A. Pramanik, RSC Adv. 31866, 5 (2015)
4. S. Moradi, M.A. Zolfigol, M. Zarei, D.A. Alonso, A. Khoshnood, A. Tajally, Appl. Organomet.
Chem. 32, e4084 (2018)
2
2
2
2
2
3
5. M. Mokhtary, J. Iran. Chem. Soc. 1827, 13 (2016)
6. A. Khorshidi, S. Shariati, M. Aboutalebi, N. Mardazad, Iran. Chem. Commun. 476, 4 (2016)
7. C. Zhang, H. Wang, F.L. Liu, H.He Wang, Cellulose 127, 20 (2013)
8. A. Ying, S. Liu, Y. Ni, F. Qiu, S. Xu, W. Tang, Catal. Sci. Technol. 2115, 4 (2014)
9. R. Baharfar, R. Azimi, Synth. Commun. 44, 89 (2014)
0. M.A. Zolfigol, R. Ayazi-Nasrabadi, S. Baghery, V. Khakyzadeh, S. Azizian, J. Mol. Catal. A: Chem.
54, 418 (2016)
1
23

Synthesis of a novel DABCO-based nanomagnetic catalyst…
3
3
3
3
3
3
1. A.R. Moosavi-Zare, M.A. Zolfigol, E. Noroozizadeh, R. salehi Moratab, M. Zarei. J. Mol. Catal. A:
Chem. 246, 420 (2016)
2. A.R. Moosavi-Zarea, M.A. Zolfigol, M. Zarei, A. Zare, V. Khakyzadeh, A. Hasaninejad, Applied
Catal A: Gen. 467, 61 (2013)
3. A.R. Moosavi-Zarea, M.A. Zolfigol, M. Zarei, A. Zare, J. Afsar, Applied Catal A: Gen. 505, 224
(
2015)
4. M.A. Zolfigol, S. Baghery, A.R. Moosavi-Zare, S.M. Vahdat, J. Mol. Catal. A: Chem. 216, 409
2015)
5. R.-Y. Guo, Z.-M. An, L.-P. Mo, R.-Z. Wang, H.-X. Liu, S.-X. Wang, Z.H. Zhang, ACS Comb. Sci.
57, 15 (2013)
6. R.D. Chandam, G.M. Abhijeet, R.P. Dayanand, B.D. Madhukar, Res. Chem. Intermed. 1411, 42
2015)
(
5
(
37. J. Feng, K. Ablajan, A. Sali, Tetrahedron 484, 70 (2014)
38. S.F. Hojati, H. Raouf, Org. Prep. Proc. Int. 474, 48 (2016)
39. N.G. Singh, M. Lily, S.P. Devi, N. Rahman, A. Ahmed, A.K. Chandra, R. Nongkhlaw, Green Chem.
4216, 18 (2016)
40. K.C. Joshi, R. Jain, S. Aroma, J. Fluorine Chem. 149, 42 (1989)
41. D.M. Pore, P.G. Hegade, D.S. Gaikwad, P.B. Patil, J.D. Patil, Lett. Org. Chem. 131, 11 (2014)
42. A.R. Moosavi-Zare, M.A. Zolfigol, M. Zarei, A. Zare, J. Afsar, Appl. Catal. A 224, 505 (2015)
123