Combining a click-multicomponent reaction: One-pot synthesis of 1,2,3-triazol-4-ylmethyl 3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2- b]phthalazine-2-carboxylate derivatives

Article abstract of DOI:10.1080/00397911.2014.888080

(1,2,3-Triazol-4-yl)methyl-3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1, 2-b]phthalazine-2-carboxylate derivatives were synthesized by a four-component, one-pot condensation reaction of benzaldehyde derivatives, an active methylene compound (prop-2-ynyl-2-cyanoacetate), azides, and phthalhydrazide in the presence of Cu(OAc)₂/sodium ascorbate as catalysts and 1-methyl-1H-imidazolium trifluoroacetate ([Hmim]TFA) as an ionic liquid medium in good to excellent yields. Copyright

Full text of DOI:10.1080/00397911.2014.888080

This article was downloaded by: [Pennsylvania State University]
On: 12 August 2014, At: 03:53
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic Organic
Chemistry
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/lsyc20
Combining a Click–Multicomponent
Reaction: One-Pot Synthesis of 1,2,3-
Triazol-4-ylmethyl 3-Amino-5,10-
dihydro-5,10-dioxo-1H-pyrazolo[1,2-
b]phthalazine-2-carboxylate Derivatives
Minoo Dabiri a , David MaGee b , Peyman Salehi c , Laleh Torkian a ,
Mahsa Fakharian a & Jordan Donahue b
a Department of Chemistry , Faculty of Science, Shahid Beheshti
University , Tehran , Iran
b Department of Chemistry , University of New Brunswick ,
Fredericton , Canada
c Department of Phytochemistry , Medicinal Plants and Drugs
Research Institute, Shahid Beheshti University , Tehran , Iran
Accepted author version posted online: 15 Apr 2014.Published
online: 09 Jun 2014.
To cite this article: Minoo Dabiri , David MaGee , Peyman Salehi , Laleh Torkian , Mahsa Fakharian
& Jordan Donahue (2014) Combining a Click–Multicomponent Reaction: One-Pot Synthesis of 1,2,3-
Triazol-4-ylmethyl 3-Amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2-b]phthalazine-2-carboxylate
Derivatives, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 44:14, 2037-2044, DOI: 10.1080/00397911.2014.888080
To link to this article: http://dx.doi.org/10.1080/00397911.2014.888080
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content

should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &
Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Synthetic Communications1, 44: 2037–2044, 2014
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2014.888080
COMBINING A CLICK–MULTICOMPONENT REACTION:
ONE-POT SYNTHESIS OF 1,2,3-TRIAZOL-4-YLMETHYL
3-AMINO-5,10-DIHYDRO-5,10-DIOXO-1H-PYRAZOLO
[1,2-b]PHTHALAZINE-2-CARBOXYLATE DERIVATIVES
Minoo Dabiri,1 David MaGee,2 Peyman Salehi,3
Laleh Torkian,1 Mahsa Fakharian,1 and Jordan Donahue2
1Department of Chemistry, Faculty of Science, Shahid Beheshti University,
Tehran, Iran
2Department of Chemistry, University of New Brunswick, Fredericton,
Canada
3Department of Phytochemistry, Medicinal Plants and Drugs Research
Institute, Shahid Beheshti University, Tehran, Iran
GRAPHICAL ABSTRACT
Abstract (1,2,3-Triazol-4-yl)methyl-3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2-
b]phthalazine-2-carboxylate derivatives were synthesized by a four-component, one-pot
condensation reaction of benzaldehyde derivatives, an active methylene compound (prop-2-
ynyl-2-cyanoacetate), azides, and phthalhydrazide in the presence of Cu(OAc)2/sodium
ascorbate as catalysts and 1-methyl-1H-imidazolium trifluoroacetate ([Hmim]TFA) as
an ionic liquid medium in good to excellent yields.
Keywords 1,3-Dipolar cycloaddition; multicomponent reaction; pyrazolo[1,2-b]
phthalazine-2-carboxylate derivatives; 1,2,3-triazoles
INTRODUCTION
Multicomponent reactions (MCRs) have emerged as an efficient synthetic
strategy over conventional linear-type synthesis because of their flexible, atom-
efficient nature and ability to create several new bonds in a one-pot reaction.
Therefore, they can achieve combinatorial synthesis of heterocyclic compounds.[1]
Received October 15, 2013.
Address correspondence to David MaGee, Department of Chemistry, University of New
Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada; or Peyman Salehi, Department of
Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, G. C., Evin,
Tehran 1983963113, Iran. E-mail: dmagee@unb.ca; p-salehi@sbu.ac.ir
Color versions of one or more of the figures in the article can be found online at www.tandfonline.
com/lsyc.
2037

2038
M. DABIRI ET AL.
Nitrogen-containing heterocyclic compounds play an important role in
biological systems. Among them, phthalazine derivatives are important targets in
synthetic and medicinal chemistry, because of their biological properties.[2,3]
Phthalazine derivatives that have two bridgehead nitrogen atoms possess
cytotoxic,[4] antimicrobial,[5] anticonvulsant,[6] antifungal,[7] anticancer,[8] and anti-
inflammatory[9] activities.
Recent protocols directed toward designing structural motifs containing
the phthalazine ring fragment usually employ multicomponent condensation of
aldehydes and active methylene compounds (malononitrile, ethyl cyanoacetate,
and dimedone) with 2,3-dihydro-1,4-phthalazinedione, also known as phthalhy-
drazides.[10–19]
‘‘Click chemistry,’’[20] introduced by Kolb et al., has become a popular method
in chemistry because of its efficient approach for the synthesis of valuable com-
pounds. One of the most reliable ‘‘click reactions’’ is Huisgen’s thermal 1,3-dipolar
cycloaddition between alkynes and azides[21] leading to 1,2,3-triazoles, which are
reported to have several biological activities, such as anti-HIV,[22] antiallergic,[23]
antifungal,[24] and antimicrobial.[25]
As a part of our continued interest in the development of methods for
the synthesis of heterocyclic compounds,[26] coupled with our experience in the
combination of multicomponent reactions and click chemistry,[27–29] we report
here a very simple and highly efficient method for the synthesis of 1,2,3-triazol-
4-ylmethyl-3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2,b]phthalazine-2-
carboxylates through a one-pot, four-component reaction. The structures of
target molecules 5a–5p were constructed by a new four-component reaction
of benzaldehyde derivatives 1a–1n, azides 2a–2e, an active methylene compound
(prop-2-ynyl-2-cyanoacetate) (3), and phthalhydrazide (4) in the presence of
Cu(OAc)2 with sodium ascorbate as catalyst and 1-methyl-1H-imidazolium
trifluoroacetate as an ionic liquid medium (Scheme 1).
Scheme 1. One-pot, four-component reaction.

COMBINING A CLICK–MULTICOMPONENT REACTION
2039
RESULTS AND DISCUSSION
In our initial research, we studied the treatment of 4-chlorobenzaldehyde (1a)
with 3-nitrophenyl azide (2a), prop-2-ynyl 2-cyanoacetate (3), and phthalhydrazide
(4) under different conditions (Table 1). By using Cu(OAc)2=sodium ascorbate as
the catalyst, the reaction was tested employing various solvents such as CH3CN,
CH2Cl2, water, and ethanol. It is worth mentioning that in the absence of catalyst
as a Brønsted acid under reflux conditions the target compound was not formed
at all (Table 1, entries 1–3). In the presence of p-TsOH as a Brønsted acid in water
or ethanol as solvent the reaction was very slow and the product was obtained
in poor yield (Table 1, entries 4 and 5). After several attempts, it was found that
by changing the solvent to [Hmim]TFA as an ionic liquid (IL) at 100 ꢀC, the desired
product 5a was isolated in 81% yield (Table 1, entry 6). Using a different IL medium
Table 1. Optimization of reaction conditionsa
Entry
Catalyst
Solvent (temperature)
Yield (%)
1
2
Cu(OAc)2=NaAsc
Cu(OAc)2=NaAsc
Cu(OAc)2=NaAsc
p-TsOH ꢁ Cu(OAc)2=NaAsc
Cu(OAc)2=NaAsc=p-TsOH
Cu(OAc)2=NaAsc
Cu(OAc)2=NaAsc
CuI
CH2Cl2 (Reflux)
CH3CN (reflux)
Trace
Trace
Trace
23
3
H2O (reflux)
H2O (reflux)
4b
5b
6c
EtOH (reflux)
53
81
[Hmim]TFA (100 ꢀC)
[Hmim]HSO4 (100 ꢀC)
[Hmim]TFA (100 ꢀC)
[Hmim]TFA (100 ꢀC)
[Hmim]TFA (100 ꢀC)
[Hmim]TFA (100 ꢀC)
[Hmim]TFA (60 ꢀC)
7c
8d
9e
10f
11g
12c
67
34
CuSO4=NaAsc
CuCl2=NaAsc
56
48
Cu(OAc)2=NaAsc
Cu(OAc)2=NaAsc
51
Trace
aReaction conditions: 4-chlorobenzaldehyde 1a (0.14 g, 1 mmol), 1-azido-3-nitrobenzene 2a (0.16 g,
1 mmol), prop-2-ynyl 2-cyanoacetate 3 (0.14 g, 1.2 mmol), phthalhydrazide 4 (0.16 g, 1 mmol), Cu(OAC)2
(0.02 g, 10 mol%), sodium ascorbate (0.04 g, 20 mol%), solvent (10 mL), 4 h.
bCu(OAC)2 (0.02 g, 10 mol%), sodium ascorbate (0.04 g, 20 mol%), and p-TSA (0.34 g, 20 mol%).
cCu(OAC)2 (0.02 g, 10 mol%), sodium ascorbate (0.04 g, 20 mol%), and [Hmim]TFA (10 mol%).
dCuI (0.019 g, 10 mol%) and [Hmim]TFA (10 mol%).
eCuSO4 (0.016 g, 10 mol%), sodium ascorbate (0.04 g, 20 mol%), and [Hmim]TFA (10 mol%).
fCuCl2 (0.013 g, 10 mol%), sodium ascorbate (0.04 g, 20 mol%), and [Hmim]TFA (10 mol%).
gCu(OAC)2 (0.01 g, 5 mol%), sodium ascorbate (0.02 g, 10 mol%), and [Hmim]TFA (10 mol%).

2040
M. DABIRI ET AL.
([Hmim]HSO4) did not give an improved yield (Table 1, entry 7). Additionally,
different copper sources such as CuI, CuCl2, and CuSO4 were screened in the model
reaction using IL catalyst and gave product in poor to moderate yields (Table 1,
entries 8–10). It was found that when the amount of the Cu decreased from 10 to
5 mol%, the yields decreased from 81 to 51%, respectively (Table 1, entry 11). It
is noteworthy that compound 5a was not produced at lower reaction temperature
(60 ꢀC) (Table 1, entry 12) but compound 7a was isolated instead.
Apparently, 7a is an intermediate of this reaction and higher temperature was
needed for completion of the reaction (Scheme 2). To check the correctness of this
hypothesis, compound 7a was synthesized and treated with compound 4 in the presence
of [Hmim]TFA at 100 ꢀC; after 5 h, the desired product 5a was obtained in 80% yield.
With this optimized procedure in hand, the scope of the four-component reac-
tion was examined by using other aromatic aldehydes 1a–1n, azides 2a–2e, prop-2-ynyl
2-cyanoacetate (3), and phthalhydrazide (4) in the presence of catalytic amounts of
Cu(OAc)2 (10 mol%), sodium ascorbate (20 mol%) and [Hmim]TFA at 100 ꢀC for
5–6 h. The results are summarized in Table 2. As can be seen, this transformation is
very general for a variety of benzaldehyde derivatives and azides. As shown
in Table 2, it was found that this procedure works with a wide variety of substrates.
Both electron-rich and electron-deficient groups on the aromatic aldehydes can be
used with equal success and five different types of azides were used in this reaction.
Although the exact mechanism of this transformation is not completely clear,
a possible pathway for this four-component reaction could be proposed in three
steps. First, formation of intermediate 6 by Knoevenagel condensation was followed
by the 1,3-dipolar cycloaddition reaction between 6 and azide 2, leading to triazole
derivative 7 as an intermediate produced from the click reaction. Then, the
subsequent Michael-type addition of phthalhydrazide (4) would give the inter-
mediate 8, followed by cyclization to afford the corresponding product 5 (Scheme 2).
The structures of the products 5a–5p were characterized by their spectroscopic
1
data. The H NMR spectra of these compounds in dimethylsulfoxide (DMSO-d6)
Scheme 2. Proposed reaction mechanism.

COMBINING A CLICK–MULTICOMPONENT REACTION
2041
Table 2. One-pot, four-component synthesis of triazolyl-phthalazine-2-carboxylates 5a–p
consisted of a characteristic peak belonging to the triazole H-atom in the region of
d ¼ 8.25–8.85 ppm. In addition, the distinguishing peak for H-C(1) of the 1H-
pyrazolo[1,2,b]phthalazine-2-carboxylate moiety was observed at d ¼ 6.05–

2042
M. DABIRI ET AL.
6.44 ppm. Another characteristic feature of the 1H NMR spectra was the appearance
of an AB signal at d ¼ 5.08–5.61 ppm, which arises from the (triazol-4-yl)CH2 unit.
Additionally, we checked the recycling of the ionic liquid. In the preparation
of 5a, the [Hmim]TFA was reused for five runs. Second and third reactions using
recovered ionic liquid afforded similar yields to those obtained in the first run.
In the fourth and fifth runs, the yields were decreased (the yields of the product
5a were 81%, 80%, 78%, 72%, and 64%, respectively).
CONCLUSION
In summary, we have developed a highly efficient method for the construc-
tion of 1,2,3-triazol-4-ylmethyl-3-amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo[1,2-b]
phthalazine-2-carboxylate skeleton via a one-pot, four-component condensation of
aromatic aldehydes, azides, prop-2-ynyl-2-cyanoacetate, and phthalhydrazide for
furnishing a class of derivatives in good yield and excellent atomic economy.
EXPERIMENTAL
Chemicals were purchased from commercial suppliers and were used without
purification. Melting points were measured on an Electrothermal 9100 apparatus
and were not corrected. High-resolution electrospray ionization–mass spectrometry
1
(HR-ESIMS) spectra were acquired on a Bruker MicroTOF ESI-MS system. H
NMR and 13C NMR spectra were recorded on a Bruker DRX-300 Avance spec-
trometer at 300.13 and 75.47 MHz, respectively, or a Varian Unity 400 spectrometer
at 400 and 100.6 MHz, respectively. Infrared (IR) spectra were recorded on a Bomem
MB-Series FT-IR spectrometer.
General Procedure for the Synthesis of Prop-2-ynyl
2-Cyanoacetate (3)[30]
Cyanoacetic acid (851 mg, 10 mmol) and prop-2-yn-1-ol (561 mg, 10 mmol) were
dissolved in dichloromethane (40 mL) and cooled to 0 ꢀC. A solution of N,N0-
dicyclohexylcarbodiimide (2.1 g, 10 mmol) and 4-dimethylaminopyridine (117 mg,
1 mmol) in dichloromethane (20 mL) was added, and the reaction mixture was stirred
for 2 h at 0 ꢀC. The solid dicyclohexylurea was filtered, and the filtrate was concen-
trated to give an oil that was purified by SiO2 chromatography (3:1 hexane–ethyl
acetate) to give 1.05 g of 3 as a colorless oil (85%). 1H NMR (399.939 MHz,
CDCl3): d ¼ 2.55 (t, 1H, J ¼ 2.4 Hz), 3.53 (s, 2H), 4.78 (d, J ¼ 2.4 Hz). 13C NMR
(100.575 MHz, CDCl3): d ¼ 24.7, 54.1, 76.2, 76.4, 112.7, 162.5.
General One-Pot Procedure for MCR–Click Reaction to Produce 1,2,3-
Triazol-4-ylmethyl 3-Amino-5,10-dihydro-5,10-dioxo-1H-pyrazolo
[1,2-b]phthalazine-2-carboxylate 5a–5p
A mixture of benzaldehyde derivatives 1a–1n (1.0 mmol), aryl azide 2a–2e
(1.0 mmol), prop-2-ynyl 2-cyanoacetate (3) (1.0 mmol), and phthalhydrazide (4)

COMBINING A CLICK–MULTICOMPONENT REACTION
2043
(1.0 mmol) in the presence of Cu(OAc)2 (0.02 g, 10 mol%), sodium ascorbate (0.04 g,
20 mol%), and [Hmim]TFA (0.5 g) were mixed thoroughly and then stirred for 4–5 h
at 100 ꢀC. After cooling, ammonium hydroxide (2 mL) and water (5 mL) were added
and stirred for 30 min. Then the solid was filtered and washed with hot ethanol to
give the pure products.
Synthesis of (1-(3-Nitrophenyl)-1H-1triazol-4-yl)methyl 3-Amino-
1-(4-chlorophenyl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]
phthalazine-2-carboxylate (5a)
A mixture of 4-chlorobenzaldehyde (1a) (0.14 g, 1.0 mmol), 3-nitrophenylazide
azide (2a) (0.16 g, 1.0 mmol), prop-2-ynyl 2-cyanoacetate (3) (0.12 g, 1.0 mmol), and
phthalhydrazide (4) (0.16 g, 1.0 mmol) in the presence of Cu(OAc)2 (0.02 g,
10 mol%), sodium ascorbate (0.04 g, 20 mol%), and [Hmim]TFA (0.5 g) were mixed
thoroughly and then stirred for 4 h at 100 ꢀC. After cooling, ammonium hydroxide
(2 mL) and water (5 mL) were added and stirred for 30 min. Then the solid was
filtered and washed with hot ethanol. Finally, the pure product 5a was obtained in
81% yield. Mp: 218–219 ꢀC. IR (KBr) (nmax=cmꢂ1): 3463, 3303, 1697, 1672, 1650,
1
1536, 1391. H NMR (300.13 MHz, DMSO-d6): d ¼ 5.15 (d, 1H, J ¼ 13.0 Hz, CH),
5.25 (d, 1H, J ¼ 13.0 Hz, CH), 6.10 (s, 1H, CH), 7.19 (d, 2H, J ¼ 8.1 Hz, HAr),
7.42 (d, 2H, J ¼ 8.1 Hz, HAr), 7.88–8.39 (m, 9H, HAr, NH2), 8.70 (s, 1H, HAr),
8.78 (s, 1H, HAr). 13C NMR (75.47 MHz, DMSO-d6): d ¼ 56.1, 62.9, 81.1, 115.2,
123.2, 123.7, 126.6, 127.1, 127.7, 128.2, 129.2, 129.3, 129.9, 132.1, 132.5, 134.1,
135.2, 137.5, 139.1, 149.0, 153.7, 157.4, 163.8. HR-MS (ESI) calcd. for C27H18ClN7
O6 [M-H] 570.0934; found 570.0928.
Ionic liquid was recovered by washing the reaction mixture with CH2Cl2 and
then evaporating it in vacuum. The recovered IL was washed with diethyl ether
and can be reused for the same reactions.
FUNDING
We gratefully acknowledge financial support from the Research Council of
Shahid Beheshti University and Catalyst Centre of Excellence (CCE). Support from
the University of New Brunswick is also gratefully acknowledged.
SUPPLEMENTARY MATERIAL
Experimental details and full characterization of compounds 5a–5p, 6a, and 7a,
1
including H and 13C spectra, can be accessed on the publisher’s website.
REFERENCES
1. Tietze, L. F.; Beifus, U. Angew. Chem. Int. Ed. 1993, 32, 131–170; (b) Tietze, L. F. Chem.
Rev. 1996, 96, 115–136; (c) Tietze, L. F.; Evers, T. H.; Topken, E. Angew. Chem. Int. Ed.
2001, 40, 903–905; (d) Ikeda, S. Angew. Chem. Int. Ed. 2003, 42, 5120–5122.
2. Khali, A. M.; Berghot, M. A.; Gouda, M. A. Eur. J. Med. Chem. 2009, 44, 4448–4454.

2044
M. DABIRI ET AL.
3. Kim, J. S.; Lee, H. J.; Suh, M. E.; Choo, H. Y. P.; Lee, S. K.; Park, H. J.; Kim, C.; Park,
S. W.; Lee, C. O. Bioorg. Med. Chem. 2004, 12, 3683–3686.
4. Kim, J. S.; Rhee, H. K.; Park, H. J.; Lee, S. K.; Lee, C. O.; Park, H. Y.; Choo, H. Y.
Bioorg. Med. Chem. 2008, 16, 4545–4550.
5. El-akka, S. S.; Soliman, A. H.; Imam, A. M. Afinidad 2009, 66, 167–172.
6. Zhang, L.; Guan, L. P.; Sun, X. Y.; Wei, C. X.; Chai, K. Y.; Quan, Z. S. Chem. Bio. Drug
Design 2009, 73, 313–319.
7. Ryu, C. K.; Park, R. E.; Ma, M. Y.; Nho, J. H. Bioorg. Med. Chem. Lett. 2007, 17, 2577–2580.
8. Li, J.; Zhao, Y. F.; Yuan, X. Y.; Xu, J. X.; Gong, P. Molecules 2006, 11, 574–582.
9. Sinkkonen, J.; Ovcharenko, V.; Zelenin, K. N.; Bezhan, I. P.; Chakchir, B. A.; Assar, F.
A.; Pihlaja, K. Eur. J. Org. Chem. 2002, 2046–2053.
10. Mosaddeg, E.; Hassankhani, A. Tetrahedron Lett. 2011, 52, 488–490.
11. Raghuvanshi, D. S.; Singh, K. N. Tetrahedron Lett. 2011, 52, 5702–5705.
12. Sayyafi, M.; Seyyedhamzeh, M.; Khavasi, H. R.; Bazgir, A. Tetrahedron 2008, 64, 2375–2378.
13. Shaterian, H. R.; Hosseinian, A.; Ghashang, M. Arkivoc 2009, 59–67.
14. Ghahremanzadeh, R.; Shakibaei, G. I.; Bazgir, A. Synlett 2008, 1129–1132.
15. Nabid, M. R.; Rezaei, S. J. T.; Ghahremanzadeh, R.; Bazgir, A. Ultrason. Sonochem.
2010, 17, 159–161.
16. Khurana, J. M.; Magoo, D. Tetrahedron Lett. 2009, 50, 7300–7303.
17. Wang, H. J.; Zhang, X. Z.; Zhang, Z. H. Monatsh Chem. 2010, 141, 425–430.
18. Shaterian, H. R.; Khorami, F.; Amirzadeh, A.; Doostmohammadi, R.; Ghashang, M.
J. Iran Chem. Res. 2009, 2, 57–62.
19. Shaterian, H. R.; Ghashang, M.; Feyzi, M. Appl. Catal. A Gen. 2008, 345, 128–133.
20. Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem. Int. Ed. 2001, 40, 2004–2021.
21. Sharpless, K. B.; Manetsch, R. Expert Opin. Drug Discovery 2006, 1, 525–538.
22. Alvarez, R.; Velazquez, S.; Felix, A. S.; Aquaro, S.; Clercq, E. D.; Perno, C. F.; Karlsson,
A.; Balzarini, J.; Camarasa, M. J. J. Med. Chem. 1994, 37, 4185–4194.
23. Buckle, D. R.; Rockell, C. J. M.; Smith, H.; Spicer, B. A. J Med. Chem. 1986, 2, 2262–2267.
24. (a) Vicentini, C. B.; Brandolini, V.; Guarneri, M.; Giori, P. Farmaco 1992, 47, 1021–1024.
(b) Fung-Tomc, J. C.; Huczko, E.; Minassian, B.; Bonner, D. P. Antimicrob. Agents
Chemother. 1998, 42, 313–318.
25. Genin, M. J.; Allwine, D. A.; Anderson, D. J.; Barbachyn, M. R.; Emmert, D. E.;
Garmon, S. A.; Graber, D. R.; Grega, K. C.; Hester, J. B.; Hutchinson, D. K.; Morris,
J.; Reischer, R. J.; Ford, C. W.; Zurenko, G. E.; Hamel, J. C.; Schaadt, R. D.; Stapert,
D.; Yagi, B. H. J. Med. Chem. 2000, 43, 953–970.
26. (a) Dabiri, M.; Bahramnejad, M.; Baghbanzadeh, M. Tetrahedron 2009, 65, 9443–9447;
(b) Dabiri, M.; Bahramnejad, M.; Bashiribod, S. Mol. Divers. 2010, 14, 507–512.
27. Dabiri, M.; Salehi, M. P.; Bahramnejad, M.; Sherafat, F. J. Comb. Chem. 2010, 12, 638–642.
28. Torkian, L.; Salehi, P.; Dabiri, M.; Bararjanian, M. Helv. Chem. Acta 2011, 94,
1416–1425.
29. Salehi, P.; Dabiri, M.; Koohshari, M.; Movahed, S. K.; Bararjanian, M. Mol. Divers.
2011, 15, 833–837.
30. McArdie, C. B.; Zhao, L. WO Patent 2008050313 (A1), May 2, 2008.