Nanostructural Cu-Doped ZnO Hollow Spheres as an Economical and Recyclable Catalyst in the Synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and Pyrazolo[1,2-a][1,2,4]triazole-1,3-diones

Full text of DOI:10.1080/00304948.2020.1765655

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
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Nanostructural Cu-Doped ZnO Hollow Spheres
as an Economical and Recyclable Catalyst in the
Synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-
diones and Pyrazolo[1,2-a][1,2,4]triazole-1,3-diones
Behrooz Maleki , Razieh Nejat , Heshmatollah Alinezhad , Seyed Mohsen
Mousavi , Behnam Mahdavi & Maryam Delavari
To cite this article: Behrooz Maleki , Razieh Nejat , Heshmatollah Alinezhad , Seyed
Mohsen Mousavi , Behnam Mahdavi & Maryam Delavari (2020): Nanostructural Cu-Doped
ZnO Hollow Spheres as an Economical and Recyclable Catalyst in the Synthesis of 1H-
pyrazolo[1,2-b]phthalazine-5,10-diones and Pyrazolo[1,2-a][1,2,4]triazole-1,3-diones, Organic
Preparations and Procedures International, DOI: 10.1080/00304948.2020.1765655
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ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
https://doi.org/10.1080/00304948.2020.1765655
EXPERIMENTAL PAPER
Nanostructural Cu-Doped ZnO Hollow Spheres as an
Economical and Recyclable Catalyst in the Synthesis
of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and
Pyrazolo[1,2-a][1,2,4]triazole-1,3-diones
Behrooz Malekia , Razieh Nejatb , Heshmatollah Alinezhadc, Seyed Mohsen
Mousavid , Behnam Mahdavia, and Maryam Delavaria
b
aDepartment of Chemistry, Hakim Sabzevari University, Sabzevar, Iran; Department of Chemistry, Kosar
c
University of Bojnord, Bojnord, Iran; Faculty of Chemistry, University of Mazandaran, Babolsar, Iran;
dDepartment of Chemistry, Farhangian University, Tehran, Iran
ARTICLE HISTORY Received 23 May 2019; Accepted 8 February 2020
In the synthesis of organic compounds, heterogeneous catalysts have gained significance
versus their homogeneous counterparts, due to both environmental and economic con-
cerns.1–4 Homogeneous catalytic systems cannot as readily be commercialized owing to
difficulties encountered with equipment corrosion, solvent recycling, isolation, and reus-
ability of the catalyst. In recent years, metallic nanoparticles have found use as heteroge-
neous catalysts.5–9 Nanometal oxides possess a surface Lewis acid (metal cation) and
Lewis base (oxygen anion),10 and they enhance organic reactions because they act as
excellent adsorbents for a wide variety of organic molecules. The high surface area to
volume ratio of the metal oxide nanoparticles is in large part responsible for their cata-
lytic activities.11 In connection with this, zinc oxide is of low cost and has been widely
used in industry.12–15 In recent years, ZnO nanostructures, including nanotowers, nano-
volcanoes, nanorods, nanotubes, nanowires, nanoflowers, and nanospheres have been
reported. Among the ZnO nanostructures, zinc oxide hollow structures have attracted
considerable attention.16–18
The use of multi-component reactions (MCRs)19–26 is becoming more prominent in
organic synthesis and represents an attractive possibility for the preparation of biologic-
ally active pyrazoles.27–32 For example, extensive studies have been accomplished on the
synthesis of pyrazolo[1,2-b]phthalazine-diones and pyrazolo[1,2-a][1,2,4]triazole-1,3-di-
ones. These compounds are known as antimicrobial, antitumor, anti-inflammatory,
analgesic, antihypotoxic, anticonvulsant, antipyretic, and antifungal agents.30–32
We now report the use of Cu-ZnO hollow sphere nanostructures as a catalyst for the
MCR preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and pyrazolo[1,2-
a][1,2,4]triazole-1,3-diones, formed from phthalhydrazide or phenylurazole, malononi-
trile and aldehydes (Scheme 1). The catalyst was rigorously characterized using the
techniques of x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR),
CONTACT Behrooz Maleki
Razieh Nejat organochem_nejat@yahoo.com
b.maleki@hsu.ac.ir
Department of Chemistry, Hakim Sabzevari University, Sabzevar, Iran;
Department of Chemistry, Kosar University of Bojnord, Bojnord, Iran
ß 2020 Taylor & Francis Group, LLC

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B. MALEKI ET AL.
Scheme 1. Synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and pyrazolo[1,2-a][1,2,4]triazole-
1,3-diones.
field emission scanning electron microscopy (FE-SEM), and energy dispersive x-ray
(EDX) analysis.
In order to establish the conditions for the title reactions, we first examined the
model condensation reaction among malononitrile 1 (1 mmol), benzaldehyde 2a
(1 mmol) and phthalhydrazide 3 (1 mmol). The effects of solvents, and conditions on
the reaction were studied (Table 1). The reaction worked best at 100 ꢀC under solvent-
free conditions using 0.020 g Cu-ZnO hollow spheres as catalyst.
To develop the scope of these reactions, several other aromatic aldehydes 2 were sub-
jected to condensation with malononitrile 1 under the optimized conditions. In general,
the reactions proceeded smoothly in relatively short reaction times (8-35 min) to afford
the respective 1H-pyrazolo[1,2-b]phthalazine-5,10-diones 4a-q in good yields (81-93%).
The experimental results are summarized in Table 2.
In a similar manner, we optimized the preparation of pyrazolo[1,2-a][1,2,4]triazole-
1,3-diones and found that the best conditions were 80 ꢀC, solvent-free, 0.020 g Cu-ZnO
hollow sphere nanostructures. These results are summarized in Table 3.
The reusability of the Cu-ZnO hollow spheres nanostructures was examined in
the model reaction among malononitrile 1 (1 mmol), benzaldehyde (1 mmol) and
phthalhydrazide 3 (1 mmol). The catalyst was readily separated from the reaction
mixture after completion of the reaction, washed with hot ethyl acetate, and used
directly for four successive runs in yields of 91%, 88%, 86% and 83% respectively,
demonstrating that the catalyst activity declined only slightly. The ease of separ-
ation and reusability of the catalyst are two of the highly desirable features of this
preparation.
In conclusion, we have developed a convenient one-pot three component cyclocon-
densation reaction for the preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and
pyrazolo[1,2-a][1,2,4]triazole-1,3-dione derivatives, using nano hollow sphere Cu-ZnO

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
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Table 1. Optimization of reaction conditions.
Entry
Conditions
Solvent
Catalyst (g)
Time (min)
Yield (%)b
1
2
3
4
5
6
7
8
9
rt
EtOH
Cu-ZnO hollow spheres (0.030)
None
100
100
20
20
20
20
60
60
60
Trace
–
ꢀ
100 C
100 C
100 C
100 C
100 C
100 C
80 C
80 C
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
H2O/Reflux
ꢀ
Cu-ZnO hollow spheres (0.005)
Cu-ZnO hollow spheres (0.010)
Cu-ZnO hollow spheres (0.020)
Cu-ZnO hollow spheres (0.030)
Cu-ZnO hollow spheres (0.020)
Cu-ZnO hollow spheres (0.020)
Cu-ZnO hollow spheres (0.020)
58
80
91
91
51
68
62
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
EtOH/Reflux
H2O: EtOH (1:1)/Reflux
ꢀ
aConditions: malononitrile (1 mmol), phthalhydrazide (1 mmol), benzaldehyde (1 mmol).
bIsolated yield.
as an economical catalyst under solvent-free conditions. This method has such advan-
tages as high yields, short reaction times, easy work-up, ease of separation and reusabil-
ity of the catalyst. We hope that our work will stimulate further research on this useful
catalyst for the preparation of heterocyclic systems.
Experimental section
Melting points were measured on an SMPI apparatus. All reagents for the synthesis and
analysis were commercially available from Merck Company and used as received. The
infrared spectra were recorded on a Nicolet Fourier Transform IR spectrometer in the
1
range 400-4000 cmꢁ1 using the KBr disk technique. H NMR spectra were obtained
using a Bruker 300 MHz spectrometer in DMSO-d6 or CDCl3 and using TMS as the
internal reference. Powder X-ray diffraction (PXRD) measurements were performed
using a Philips X’pert diffractometer with monochromated Cu-Ka radiation (k¼
1.54056 Å). Also, the morphology of samples was characterized by a field emission
scanning electron microscope (FE-SEM) (Mira TESCAN) with gold coating. Powder
XRD patterns were recorded at room temperature using a Philips X’pert 1710 diffract-
ometer with Co Ka radiation (k ¼ 1.78897 Å). The corresponding EDX spectrum was
obtained with a Holland Philips XL30 microscope.
Carbon spheres
The preparation route used for carbon spheres is as follows:29 Initially, fructose (10 g)
was dissolved in 100 ml of deionized water to obtain a transparent solution. Then, the
formed homogeneous solution was sealed in a Teflon-lined stainless steel autoclave. The

4
B. MALEKI ET AL.
Table 2. One-pot synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones (4a-q) catalyzed by Cu-ZnO
hollow spherical nanostructures.
Mp (ꢀC)
Entry
Products
Time (min)
20
Yield (%)
91
Found
Reported
276-27834
4a
275-276
4b
8
93
227-229
228-22935
4c
10
93
268-270
269-27136
4d
17
91
265-266
262-26437
4e
20
89
232-233
270-27238
(continued)

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
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Table 2. Continued.
Mp (ꢀC)
Entry
Products
Time (min)
20
Yield (%)
85
Found
Reported
253-25534
4f
250-252
4g
25
81
247-251
248-25036
4h
10
87
248-250
248-25018
4i
10
90
263-264
267-26838
4j
25
85
190-193
192-19434
(continued)

6
B. MALEKI ET AL.
Table 2. Continued.
Mp (ꢀC)
Reported
155-15738
Entry
Products
Time (min)
30
Yield (%)
81
Found
4k
154-156
4l
10
87
263-264
265-26718
4m
12
90
268-271
267-27018
4n
35
87
269-270
271-27318
4o
15
88
269-272
268-27034
(continued)

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
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Table 2. Continued.
Mp (ꢀC)
Entry
Products
Time (min)
12
Yield (%)
92
Found
Reported
242-24439
4p
240-243
4q
14
91
281-283
282-28439
autoclave was heated to 160 ꢀC for 4 h. The hot solution was then gradually cooled to
room temperature, and the resultant carbon spheres were separated from the suspension
and subsequently washed three times with deionized water. Finally, the spheres were
dried at 80 ꢀC for 2 h in a way that excessive water was evaporated.
Cu-doped ZnO hollow spheres
In order to prepare x-Cu-ZnO (x ¼ 10 wt % Cu) hollow spheres, the stoichiometric
quantities of zinc(II) acetate dihydrate and cupper(II) acetate dihydrate of analytical
reagent grade were dissolved in 40 mL deionized double distilled water (solution A).
Separately, a solution was prepared by dispersing carbon microspheres (1 g) in 20 ml
of deionized double distilled water (solution B). Solution B was dispersed in the
ultrasonic bath at room temperature for 1 h and solution A was mixed dropwise
into this solution with constant stirring. The mixed solution was then aged for one
day under ambient conditions. Subsequently, the product was concentrated by cen-
trifugation and washed three times with 20 mL deionized water in order to remove
impuritieꢁs.1 Finally, the product was annealed from room temperature to 500 ꢀC at
1 ꢀC min rate and placed at 500 ꢀC for 2 hours in air to obtain the Cu-ZnO hollow
spherical nanostructures with a dark gray color. The catalyst was rigorously charac-
terized using the techniques of x-ray diffraction, infrared spectroscopy, field emission
scanning electron microscopy, and energy dispersive x-ray analysis. The data were
submitted for review and are available from the corresponding author upon request.

8
B. MALEKI ET AL.
Synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and pyrazolo[1,2-a]
[1,2,4]triazole-1,3-diones
A mixture of aldehyde 2 (1.0 mmol), malononitrile 1 (1.0 mmol), phthalhydrazide 3
(1.0 mmol) or phenylurazole 5 (1.0 mmol) and Cu-ZnO hollow spheres (0.02 g) were
placed in a test tube. The reaction mixture was then heated at 100 ꢀC for an appropriate
time (Tables 2 and 3) until the completion of the reaction was achieved as monitored
by TLC. Then, the crude product was dissolved in hot ethyl acetate and then filtered to
remove the solid catalyst. The filtrate was cooled to give the pure organic product, iden-
tified by comparison of the observed melting point with the literature value.
Representative spectroscopic data for selected examples are shown below, for the sake
of completeness.
3-Amino-1-(2,4-dichlorophenyl)-5,10-dihydro-5,10-dioxo1H-pyrazolo[1,2-b]phthala-
zine-2-carbonitrile (4q)
1H-NMR (300 MHz, DMSO-d6): d 6.43 (s, 1H, CH), 7.39–8.25 (m, 9H, Ar–H and NH2)
ppm; 13C-NMR (75 MHz, DMSO-d6): d 61.2, 62.5, 116.5, 127.1, 127.9, 128.6, 128.9,
129.2, 129.8, 130.3, 130.5, 131.5, 134.4, 138.2, 138.9, 151.6, 154.1, 157.0; IR (KBr, cmꢁ1):
3364, 3262, 2197, 1681, 1660.
7-Amino-1,3-dioxo-2,5-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]triazole-6-carboni-
trile (6a)
1H NMR (500 MHz, DMSO-d6): d 5.95 (1H, s, CH), 7.08–8.12 (12H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 61.2, 63.3, 116.2, 126.1, 126.9, 127.7, 128.3,
128.7, 129.8, 133.4, 145.1, 150.1, 150.5, 153.3; IR (KBr, cmꢁ1): 3365, 3301, 2191,
1651, 1578.
7-Amino-5-(4-chlorophenyl)-1,3-dioxo-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6- carbonitrile (6b)
1H NMR (500 MHz, DMSO-d6): d 5.89 (1H, s, CH), 7.42–7.67 (11H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 61.9, 64.5, 116.8, 127.5, 128.9, 129.2, 129.5,
130.1, 134.6, 137.9, 145.7, 150.4, 150.6, 153.8; IR (KBr, cmꢁ1): 3364, 3260, 2187,
1654, 1567.
7-Amino-1,3-dioxo-5-(4-nitrophenyl)-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6-carbonitrile (6c)
1H NMR (500 MHz, DMSO-d6): d 5.97 (1H, s, CH), 7.44–8.32 (11H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 61.0, 63.2, 116.37, 124.2, 126.9, 128.4, 128.9,
129.1, 129.6, 131.0, 146.2, 150.37, 150.6, 153.7; IR (KBr, cmꢁ1): 3363, 3255, 2289,
1648, 1565.

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
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Table 3. One-pot synthesis of pyrazolo[1,2-a][1,2,4]triazole-1,3-diones (6a-h) catalyzed by Cu-ZnO
hollow spheres nanostructures.
Mp (ꢀC)
Entry
Products
Time (min)
35
Yield (%)
89
Found
210
Reported
21040
6a
6b
6c
6d
15
20
20
90
92
91
221
217
200
22140
21840
20040
6e
18
90
214
21440
6f
25
88
217
21640
(continued)

10
B. MALEKI ET AL.
Table 3. Continued.
Mp (ꢀC)
Reported
Entry
Products
Time (min)
Yield (%)
Found
6g
30
89
220
22140
6h
20
91
224
22440
7-Amino-5-(2,4-dichlorophenyl)-1,3-dioxo-2-phenyl-1,2,3-dihydropyrazolo[1,2-
a][1,2,4]triazole-6-carbonitrile (6d)
1H NMR (500 MHz, DMSO-d6): d 6.22 (1H, s, CH), 7.43–7.70 (10H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 60.5, 61.1, 116.0, 126.7, 128.7, 129.0, 129.2,
129.9, 130.9, 131.0, 132.7, 134.0, 135.1, 150.2, 150.5, 153.5; IR (KBr, cmꢁ1): 3363, 3262,
2191, 1647, 1565.
7-Amino-1,3-dioxo-5-(3-nitrophenyl)-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6-carbonitrile (6e)
1H NMR (300 MHz, DMSO- d6): d 6.08 (1H, s, CH), 7.43–8.35 (11H, m, H–Ar and
NH2); 13C NMR (75 MHz, DMSO-d6): d 60.8, 63.0, 116.3, 121.5, 123.6, 126.8, 128.7,
129.0, 129.5, 130.9, 133.6, 141.5, 148.1, 150.3, 150.5, 153.7; IR (KBr, cmꢁ1): 3369, 3252,
2103, 1629, 1556.
7-Amino-5-(3-chlorophenyl)-1,3-dioxo-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6- carbonitrile (6f)
1H NMR (500 MHz, DMSO-d6): d 6.17 (1H, s, CH), 7.23–7.80 (11H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 61.2, 63.2, 116.3, 121.1, 126.8, 127.2, 128.1,

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
11
128.8, 129.8, 130.7, 135.2, 135.9, 145.6, 150.3, 150.6, 153.6; IR (KBr, cmꢁ1): 3370, 3233,
2209, 1655, 1563.
7-Amino-5-(3-bromophenyl)-1,3-dioxo-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6-carbonitrile (6g)
1H NMR (500 MHz, DMSO-d6): d 5.88 (1H, s, CH), 7.40–7.68 (11H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 61.1, 63.1, 116.4, 121.9, 126.0, 128.6, 128.9,
129.6, 130.9, 131.0, 131.4, 141.8, 145.4, 150.1, 150.4, 153.5; IR (KBr, cmꢁ1): 3450, 3273,
2203, 1661, 1526.
7-Amino-5-(4-bromophenyl)-1,3-dioxo-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]tri-
azole-6-carbonitrile (6h)
1H NMR (500 MHz, DMSO-d6): d 5.77 (1H, s, CH), 7.00–7.60 (11H, m, H–Ar and
NH2). 13C NMR (125 MHz, DMSO-d6): d 60.8, 61.3, 116.4, 126.5, 127.8, 128.7, 129.0,
129.9, 130.2, 131.1, 133.3, 137.7, 144.5, 150.1, 153.3; IR (KBr, cmꢁ1): 3372, 3276, 2212,
1673, 1603.
Acknowledgments
We gratefully acknowledge financial support from the Research Council of Hakim Sabzevari
University, Kosar University of Bojnord, and Farhangian University of Tehran.
ORCID
Behrooz Maleki
Razieh Nejat
http://orcid.org/0000-0002-0322-6991
http://orcid.org/0000-0001-8742-2342
Seyed Mohsen Mousavi
http://orcid.org/0000-0003-3031-912X
References
1. S. Ikegami and H. Hamamoto, Chem. Rev., 109, 583 (2009). doi:10.1021/cr800481x
2. B. Maleki, H. Alinezhad, H. Atharifar, R. Tayebee and A. Vedad Mofrad, Org. Prep. Proced.
Int., 51, 301 (2019). doi:10.1080/00304948.2019.1600132
3. B. Maleki, M. Raei, E. Akbarzadeh and H. Alinezhad and A. Sedrpoushan, Org. Prep. Proced.
Int., 50, 288 (2018). doi:10.1080/00304948.2018.1462055
4. B. Maleki, R. Tayebee and S. Sedigh Ashrafi, Org. Prep. Proced. Int., 49, 542 (2017). doi:10.
1080/00304948.2017.1384260
5. G.M. Scheuermann, L. Rumi, P. Steure, W. Bannwarth, and R. Mulhaupt, J. Am. Chem. Soc.,
131, 8262 (2009). doi:10.1021/ja901105a
6. A. Jamshidi, B. Maleki, F. Mohammadi Zonoz and R. Tayebee, Mater. Chem. Physic., 209, 46
(2018). doi:10.1016/j.matchemphys.2018.01.070
7. A. Khojastehnezhad, B. Maleki, B. Karrabi and E. Rezaei Seresht, Org. Prep. Proced. Int., 49,
338 (2017). doi:10.1080/00304948.2017.1342505
8. B. Maleki, E. Sheikh, E. Rezaei Seresht, H. Eshghi, S. Sedigh Ashrafi, A. Khojastehnezhad
and H. Veisi, Org. Prep. Proced. Int., 48, 37 (2016). doi:10.1080/00304948.2016.1127098
9. S. Hemmati, P. Mohammadi, A. Sedrpoushan and B. Maleki, Org. Prep. Proced. Int., 15, 465
(2018). doi:10.1080/00304948.2018.1525668
10. K. Tanabe, Solid Acids and Bases: their catalytic applications; Academic Press: New York, 1970.
11. A. T. Bell, Science., 299, 1688 (2003). doi:10.1126/science.1083671

12
B. MALEKI ET AL.
12. M. Hosseini Sarvari and H. Sharghi, J. Org. Chem., 69, 6953 (2004). doi:10.1021/jo0494477
13. E. K. Goharshadi, Y. Ding and P. Nancarrow, J. Phys. Chem. Solids., 69, 2057 (2008). doi:10.
1016/j.jpcs.2008.03.002
14. F. Matloubi Moghaddam and H. Saeidian, Mater. Sci. Eng. B., 139, 265 (2007). doi:10.1016/j.
mseb.2007.03.002
15. F. Tamaddon, M.A. Amrollahi and L. Sharafat, Tetrahedron Lett., 46, 7841(2005). doi:10.
1016/j.tetlet.2005.09.005
16. A. Kołodziejczak-Radzimska and T. Jesionowski, Materials 7, 2833 (2014). doi:10.3390/
ma7042833
17. S. M. Mousavi, A.R. Mahjoub and R. Abazari, J. Mol. Liq., 242, 512 (2017). doi:10.1016/j.
molliq.2017.07.050
18. A. Azarifar, R. Nejat-Yami and D. Azarifar, J. Iran. Chem. Soc., 10, 297 (2013). doi:10.1007/
s13738-012-0159-3
19. B. Maleki, Org. Prep. Proced. Int., 48, 303 (2016). doi:10.1080/00304948.2016.1165061
20. B. Maleki, Org. Prep. Proced. Int., 47, 173 (2015). doi:10.1080/00304948.2015.1005990
€
21. A. Domling and I. Ugi, Angew Chem. Int. Ed., 39, 3168 (2000). doi:10.1002/1521-
3773(20000915)39:18<3168::AID-ANIE3168>3.0.CO;2-U
22. B. Maleki and S. Sheikh, Org. Prep. Proced. Int., 47, 368 (2015). doi: 10.1080/00304948.2015.
1066647
23. B. Maleki and H. Veisi, Org. Prep. Proced. Int., 52, 232 (2020). doi:10.1080/00304948.2020.
1752606.
24. B. Maleki, M. Chahkandi, R. Tayebee, S. Kahrobaei, H. Alinezhad and S. Hemmati, Appli.
Organomet. Chem., 29, e5118 (2019).
25. F. Adibian, A. R. Pourali, B. Maleki, M. Baghayeri and A. Amiri, Polyhedron 175, 114179
(2020). doi:10.1016/j.poly.2019.114179
26. B. Maleki, O. Reiser, E. Esmaeilnezhad and H. J. Choi, Polyhedron 162, 129 (2019). doi:10.
1016/j.poly.2019.01.055
27. E. C. Franklin, Chem. Rev., 16, 305 (1935). doi:10.1021/cr60055a001
28. F. W. Bergstrom, Chem. Rev., 35, 77 (1944). doi:10.1021/cr60111a001
29. F. W. Lichtenthaler, Acc. Chem. Res., 35, 728 (2002). doi:10.1021/ar010071i
30. F. Al’-Assar, K. N. Zelenin, E. E. Lesiovskaya, I. P. Bezhan and B. A. Chakehir, J. Pharm.
Chem., 36, 598 (2002). doi:10.1023/A:1022665331722
31. A. Kiriazis, T. Ruffer, S. Jantti, H. Lang and J. Yli-Kauhaluama, J. Comb. Chem., 9, 263
(2007). doi:10.1021/cc060125l
32. V. M. Kolb, J. P. Dworkin and S. L. Miller, J. Mol. Evol., 38, 549 (1994).
33. H. M. Abdelaal and B. Harbrecht, C. R. Chim., 18, 379 (2015). doi:10.1016/j.crci.2014.08.004
34. B. Maleki, S. Barat Nam Chalaki, S. Sedigh Ashrafi, E. Rezaee Seresht, F. Moeinpour, A.
Khojastehnezhad and R. Tayebee, Appli. Organomet. Chem., 29, 290 (2015). doi:10.1002/aoc.3288
35. D. S. Raghuvanshi and K. N. Singh, Tetrahedron lett., 52, 5702 (2011). doi:10.1016/j.tetlet.
2011.08.111
36. H. R. Shaterian, M. Mohammadnia, J. Mol. Liq., 173, 55 (2012). doi:10.1016/j.molliq.2012.06.
007
37. M. Lashkari, R. Heydari and F. Mohamadpour, Iran J Sci Technol Trans Sci., 1 (2016). doi:
10.1007/s40995-016-0049-0
38. M. V. Reddy and Y. T. Jeong, Tetrahedron Lett., 54, 3546 (2013). doi:10.1016/j.tetlet.2013.04.109
39. G. M. Ziarani, N. H. Mohtasham, A. Badiei and N. Lashgari, J. Chin. Chem. Soc., 61, 990
(2014). doi:10.1002/jccs.201300538
40. H. R. Shaterian and F. Moradi, Res. Chem Intermed., 41, 223 (2015). doi:10.1007/s11164-013-
1184-2