One-pot sequential diprop-2-ynylation and cycloaddition: An efficient synthesis of novel N,N-bis(1,2,3-triazol-4-yl) methylarylamines starting from primary amines

Article abstract of DOI:10.1080/00397911.2019.1643482

A facile, one-pot synthesis strategy for the tertiary arylamines bearing N,N-bis(1,2,3-triazol-4-yl)methyl structure has been developed by sequential diprop-2-ynylation of primary amines with propargyl bromide in the presence of calcium hydride in DMF and [3 + 2] “click” cycloaddition with organic azides promoted by cupric acetate in the mixed DMF-H₂O media. This protocol provides some features, such as high efficiency and regioselectivity, easy operation, and moderate to good product yield (56–84%) with a wide substrate scope under mild conditions.

Full text of DOI:10.1080/00397911.2019.1643482

Synthetic Communications
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ISSN: 0039-7911 (Print) 1532-2432 (Online) Journal homepage: https://www.tandfonline.com/loi/lsyc20
One-pot sequential diprop-2-ynylation and
cycloaddition: An efficient synthesis of novel N,N-
bis(1,2,3-triazol-4-yl) methylarylamines starting
from primary amines
Zhu-Jun He, Mei-Hong Wei, Xiao-Lan Zhang, Jun-Min Chen & Shou-Ri Sheng
To cite this article: Zhu-Jun He, Mei-Hong Wei, Xiao-Lan Zhang, Jun-Min Chen & Shou-Ri
Sheng (2019): One-pot sequential diprop-2-ynylation and cycloaddition: An efficient synthesis
of novel N,N-bis(1,2,3-triazol-4-yl) methylarylamines starting from primary amines, Synthetic
Communications, DOI: 10.1080/00397911.2019.1643482
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https://doi.org/10.1080/00397911.2019.1643482
One-pot sequential diprop-2-ynylation and cycloaddition:
An efficient synthesis of novel N,N-bis(1,2,3-triazol-4-yl)
methylarylamines starting from primary amines
Zhu-Jun Hea, Mei-Hong Weia, Xiao-Lan Zhanga,b, Jun-Min Chena, and
Shou-Ri Shenga
aKey Laboratory of Functional Small Organic Molecule, Ministry of Education, Jiangxi Normal University,
b
Nanchang, People’s Republic of China; College of Chemistry and Chemical Engineering, Shangrao
Normal University, Shangrao, People’s Republic of China
ABSTRACT
ARTICLE HISTORY
Received 24 January 2019
A facile, one-pot synthesis strategy for the tertiary arylamines bear-
ing N,N-bis(1,2,3-triazol-4-yl)methyl structure has been developed by
sequential diprop-2-ynylation of primary amines with propargyl
bromide in the presence of calcium hydride in DMF and [3 þ 2]
“click” cycloaddition with organic azides promoted by cupric acetate
in the mixed DMF-H2O media. This protocol provides some features,
such as high efficiency and regioselectivity, easy operation, and mod-
erate to good product yield (56–84%) with a wide substrate scope
under mild conditions.
KEYWORDS
Cycloaddition;
diprop-2-ynylation;
N,N-bis(1,2,3-triazol-4-yl)
methylarylamines;
one-pot procedure
GRAPHICAL ABSTARCT
Ar NH2
R
N3
CaH2
DMF
N
N
R
+
R N
Ar
N
N
Ar
N
N
Cu(OAc)2 H2O
N
CH2Br
sodium ascorbate
Introduction
Aromatic amines and 1,2,3-triazoles are all nitrogen-containing compounds. Aromatic
amines are widely used as versatile building blocks for organic synthesis, natural prod-
ucts, agrochemicals, pharmaceuticals, and material science.[1] The formation of C–N
bond through cross-coupling reaction of primary amines and organic halides has been
applied as the major method to prepare secondary and tertiary amines.[2] 1,2,3-Triazoles
have displayed an ample range of application in synthetic, pharmaceutical, agrochem-
ical, medicinal and material chemistry.[3] Introduction of triazole scaffold into amines is
meaningful research to explore biologically active compounds and pharmaceutical
agents. As far as we know, some synthetic methods have been developed for the
construction of triazolyl-containing amines.[4] However, arylamines with N,N-bis(1,2,3-
triazol-4-yl)methyl groups have been reported only rarely.[5] It is well known that
CONTACT Shou-Ri Sheng
shengsr@jxnu.edu.cn
Key Laboratory of Functional Small Organic Molecule, Ministry of
Education, Jiangxi Normal University, Yaohu Campus, Nanchang 330022, People’s Republic of China.
Supplemental data for this article can be accessed on the publisher’s website.
ß 2019 Taylor & Francis Group, LLC

2
Z.-J. HE ET AL.
R N3 (3)
Base
N
Ar NH2
Ar
N
N R
+
CH2Br
R N
N
Ar
N
N
N
Solvent
1
2
4
One-pot operation
Scheme 1. Access to N,N-bis(1,2,3-triazol-4-yl)methylarylamines (4) by a diprop-2-ynylation and
CuAAC sequence.
Base
NH2
+
CH2Br
N
Solvent
1a
2a
Scheme 2. Formation of N,N-di(prop-2-yn-1-yl)aniline (2a).
copper-catalyzed alkyne-azide cycloaddition (CuAAC), a click chemistry reaction, is one
of the most attractive methods for the regioselective synthesis of 1,4-disubstituted 1,2,3-
triazole derivatives for a different purpose.[6] Although there are numerous methods for
the preparation of 1,4-disubstituted 1,2,3-triazoles, the starting materials are mainly ter-
minal alkynes that need to be prepared and isolated separately. Obviously, the gener-
ation of terminal alkynes in situ from suitable precursors, followed by the reaction with
azides in a one-pot process to form the corresponding 1,2,3-triazoles would avoid the
difficulties associated with the volatile nature of terminal alkynes. Recently, our group
has been engaged in the development of new multi-component and one-pot reactions
for the preparation of 1,2,3-triazole derivatives under various conditions.[7] Herein, we
would like to report our recent efforts to a facile and one-pot synthesis of N,N-
bis(1,2,3-triazol-4-yl)methylarylamines, involving in situ generations of terminal alkynes,
N,N-di(prop-2-yn-1-yl)arylamines through diprop-2-ynylation of primary amines with
propargyl bromide, followed by CuAAC reaction with organic azides, as outlined in
Scheme 1.
In order to find the most suitable reaction conditions for our purpose, aniline (1a),
propargyl bromide and phenyl azide (3a) were chosen as model substrates for the prep-
aration of N,N-bis[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl]aniline (4a). Initially, the
diprop-2-ynylation conditions of 1a with propargyl bromide, the key to the success of
this protocol were investigated (Scheme 2).
It was reported N,N-di(prop-2-yn-1-yl)aniline (2a) could be obtained in 80% yield by
reaction of 1a with propargyl bromide in N,N-dimethylformamide (DMF) at room tem-
perature in the presence of potassium carbonate.[8] Encouraged by this positive result,
other polar solvents and bases were further screened (Table 1, entries 2–8). Clearly,
good yield of 2a in the model reaction was obtained in DMF and dimethylsulfoxide
(DMSO) in the presence of different bases such as potassium carbonate, N,N-diisopro-
pylethylamine (DIPEA) and calcium hydride (CaH2) (Table 1, entries 1, 2, 7, and 8).
Among them, the presence of CaH2 was shown to be very effective for the reaction to
occur (Table 1, entry 8). After a considerable number of experiments, 2a was produced

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SYNTHETIC COMMUNICATIONSV
3
Table 1. Optimization of the diprop-2-ynylation conditions of 1aa.
Entry
Solvent
Base (mol %)
Time (h)
Yield (%)b
c
1
DMF
K2CO3
6
6
6
6
6
6
6
6
6
6
8
8
80
78
65
68
60
72
82
85
90
92
95
96
2
3
4
5
DMSO
Dioxane
MeCN
THF
K2CO3 (20)
K2CO3 (20)
K2CO3 (20)
K2CO3 (20)
Et3N (20)
6
DMF
7
8
9
10
11
12
DMF
DMF
DMF
DMF
DMF
DMF
DIPEA (20)
CaH2 (20)
CaH2 (30)
CaH2 (40)
CaH2 (40)
CaH2 (50)
aUnless otherwise noted, all reaction was performed with 1.0 mmol of aniline (1a), 4.0 mmol of propargyl bromide, 5 mL
c
of solvent at room temperature. bIsolated yield after column chromatography, based on 1a. The data are cited from
the work of Ji et al.[8]
Catalyst / Solvent
N
N C6H5
N
+
C6H5 N
PhN3
N
C6H5 N
N
N
Temp. / Time
2a
3a
4a
Scheme 3. [3 þ 2]-Cycloaddition of 2a with phenyl azide (3a).
Table 2. Optimization for the click process between 2a and 3aa.
Entry
Catalyst/Time/Temp
Yield of 4a (%)b
1
2
3
4
5
6
7
8
CuCl2, sodium ascorbate, DMF, rt, 6 h
Cu(OAc)2, sodium ascorbate, DMF, rt, 6 h
CuSO4, sodium ascorbate, DMF, rt, 6 h
44
55
51
50
63
72
78
83
CuCl2 ꢀ 2H2O, sodium ascorbate, DMF, rt, 6 h
CuSO4 ꢀ 5H2O, sodium ascorbate, DMF, rt, 6 h
Cu(OAc)2 ꢀ H2O, sodium ascorbate, DMF, rt, 6 h
Cu(OAc)2 ꢀ H2O, sodium ascorbate, DMF, 60 ꢁC, 4 h
Cu(OAc)2 ꢀ H2O, sodium ascorbate, DMF-H2O (5:1), 60 ꢁC, 2 h
aCopper(II) salt (0.2 mmol), sodium ascorbate (0.1 mmol), and phenyl azide (1.0 mmol) were used. bIsolated yield based
on aniline after column chromatography.
in 95% yield when the reaction was carried out in DMF at room temperature in the
presence of 40 mol.% CaH2 for 8 h (Table 1, entry 11).
After the completion of the diprop-2-ynylation, the excess propargyl bromide was
removed by vacuum distillation. Without further isolation and purification of the inter-
mediate 2a, the subsequent [3 þ 2] cycloaddition reaction with 3a for the target mol-
ecule 4a, as shown in Scheme 3, was studied, and the corresponding results are
summarized in Table 2.
As mentioned earlier, CuAAC reaction has been used to prepare 1,4-disubstituted-
1H-1,2,3-triazoles exclusively. Although copper(I) salts can be directly used, practically,
Cu(I) salts generated in situ by reduction of copper(II) salts was less costly and was
reported to give more pure material than some Cu(I) salts that were commercially avail-
able. Moreover, by this method, the reaction can be smoothly performed under milder
conditions avoiding the use of inert atmospheres. Therefore, copper(II) salts such as

4
Z.-J. HE ET AL.
Table 3. Sequential transformation of different arylamines and azides into N,N-bis(1,2,3-triazol-4-yl)
methylarylamines (4).
Entry
Ar
R
Product
Yield (%)a
1
2
3
4
5
6
7
8
C6H5
C6H5
C6H5
C6H5
C6H5
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
83
64
66
59
83
81
63
70
61
84
58
61
56
81
66
80
0
2-CH3C6H4
2-CH3OC6H4
2-ClC6H4
C6H5CH2
C6H5
2-CH3C6H4
2-CH3OC6H4
2-ClC6H4
C6H5
3-CH3C6H4
3-CH3C6H4
3-CH3C6H4
3-CH3C6H4
3-CH3C6H4
2-CH3C6H4
2-CH3C6H4
2-CH3C6H4
2-CH3C6H4
4-ClC6H4
4-ClC6H4
C6H5
9
10
11
12
13
14
15
16
17
18
C6H5CH2
2-CH3C6H4
2-CH3OC6H4
2-ClC6H4
3-CH3C6H4
2-CH3OC6H4
C6H5CH2
2-NO2C6H4
2-pyridyl
C6H5
0
aIsolated yield based on the corresponding arylamine after column chromatography.
copper sulfate and cupric acetate, together with a reducing reagent like sodium ascor-
bate were employed in the ring formation between 2a with 3a. After preliminary screen-
ing of several copper salts (Table 2, entries 1–6), Cu(OAc)2 ꢀ H2O was be found to be
the most effective (Table 2, entry 6). In addition, when the reaction was heated to an
elevated temperature of 60 ꢁC for 4 h, 4a with 78% yield as an exclusive product was
isolated (Table 2, entry 7). To our delight, the addition of a small amount of water into
the reaction system resulted in a good yield of 83% and shorter reaction time at 60 ꢁC
for 2 h (Table 2, entry 8), which may be due to the increased solubility of sodium ascor-
bate and copper salt in the solvent.
The structure of 4a was characterized by NMR spectroscopic and mass spectrometric
1
data. In the H NMR spectrum of 4a, a characteristic singlet appeared at d ¼ 8.76 ppm
due to the triazolyl C5–H proton and a singlet at d ¼ 4.82 for ArNCH2 along with other
protons. In its 13C NMR spectrum the ArNCH2 carbon appeared at d ¼ 46.2, C4 of the
triazole ring appeared at d ¼ 146.3 and C5 at d ¼ 121.8 along with other carbons.
Besides, the mass spectrum data of this compound were in agreement with the calcu-
lated values.
Finally, the optimized reaction conditions were extended to a variety of primary aro-
matic amines and organic azides with different substituents. As shown in Table 3, for
most of the examined substrates, experiments were performed smoothly and the corre-
sponding tertiary arylamines containing N,N-bis(1,2,3-triazol-4-yl)methyl groups were
obtained. In general, no significant difference in reactivity was observed for the exam-
ined arylamines substituted by 3-Me, 2-Me, 4-Cl on the benzene rings (Table 3, entries
6–16). It is noteworthy that a variety of functional groups such as chloro, methyl, and
methoxy were tolerated on aromatic azides that could be successfully converted to the
desired product in moderate to good yields (Table 3, entries 2–4, entries 7–9, and
entries 11–15). Moreover, benzyl azide also reacted satisfactorily in all reactions
(Table 3, entries 5, 10, and 16). However, low yields were found when the organic
azides were hindered (Table 3, entries 2–4, entries 7–9, entries 11–13 and 15), and

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SYNTHETIC COMMUNICATIONSV
5
sensitive functional groups like 2-nitrophenyl azide and heterocyclic azide rendered the
cycloaddition unresponsive (Table 3, entries 17 and 18). In addition, alkyl azide like
n-butylazide instead of aryl azide tested in the similar procedure did not afford the cor-
responding product.
In summary, a facile and efficient, one-pot method for the preparation of
N,N-bis(1,2,3-triazol-4-yl)methylarylamines from primary amines, propargyl bromide
and organic azides has been developed. The procedure does not require isolation of the
N,N-dipropargylated arylamine intermediates, and has considerable advantages in terms
of its use of easily available substrates, its mild reaction conditions, its simple operation,
and the moderate-to-good yields.
Experimental
Melting points were measured with a Beijing-Taike X-4 apparatus (Beijing, China) with-
1
out corrections. H NMR and 13C NMR spectra were recorded on an Avance-Bruker
400 MHz NMR spectrometer (Billerica, MA), operating at 400 and 100 MHz, respect-
ively. Chemical shifts are reported in ppm relative to TMS or the deuterated solvent as
an internal reference. IR analyses were performed with a Perkin-Elmer SP One FT-IR
spectrophotometer (Waltham, MA). Microanalyses were performed with a Carlo Erba
1106 Elemental Analyzer (CE Elantech, Lakewood, NJ). Mass spectra were recorded on
a Thermofisher scientific LCQ FLEET mass spectrometer. All organic azides are known
compounds and were prepared from primary amine using sodium nitrite and hydrazine
hydrate at room temperature through the reported method.[9] Other reagents and sol-
vents were purchased from commercial suppliers and were used as received without fur-
ther purification. All experiments were carried out in air. Analytical TLC was carried
out on Merck 0.2-mm silica gel 60 F254 analytical aluminum plates, and the products
were visualized by UV detection. Column chromatography was performed on Merck sil-
ica gel 60 (250–400 mesh).
General procedure for the preparation of N,N-Bis(1,2,3-triazol-4-yl)
methylarylamines
To a stirred solution of primary amine (1) (1.0 mmol) in DMF (5 mL) was added cal-
cium hydride (20 mg, 0.4 mmol) and propargyl bromide (480 mg, 4.0 mmol). The
mixture was stirred at room temperature until the complete conversion of amine to
N,N-di(prop-2-yn-1-yl)arylamine (2) (as monitored by TLC). The excess of propargyl
bromide was then removed under reduced pressure. After this, water (1 mL),
Cu(OAc)2 ꢀ H2O (40 mg, 0.2 mmol), sodium ascorbate (20 mg, 0.1 mmol), and organic
azide (3) (1.0 mmol) were added to the reaction mixture and stirred for 30 min. Then
the reaction mixture was warmed up to 60 ꢁC and stirred until the completion of the
reaction (by TLC). The resulting solution was filtered through a short pad of Celite 545,
and the solvent was removed under reduced pressure. The crude product was purified
by column chromatography on silica gel using (petroleum ether/EtOAc ¼ 10:1) to afford
the target compound 4.

6
Z.-J. HE ET AL.
1
Characterization data of all target compounds, copies of H NMR and 13C NMR
spectra of all compounds can be found through the “Supplementary Content” section of
this article’s webpage.
Acknowledgments
The authors thank Prof. J.-F. Zhao and Dr. Z.-M. Zhang for providing MS analytical services.
Funding
Financial support from the National Natural Science Foundation of China [21762022], the
Research Program of Jiangxi Province Department of Education [GJJ160289, GJJ170934], the
Opening Foundation of National Research Center for Carbohydrate Synthesis [GJDTZX-KF-
201414] and the Opening Foundation of Key Laboratory of Functional Small Organic Molecule
of Ministry of Education [KLFS-KF-201411] is gratefully acknowledged.
References
[1] Lawrence, S. A. Amines: Synthesis Properties and Applications; Cambridge University
Press: Cambridge, UK, 2004.
[2] (a) Gawronski, J.; Wascinska, N.; Gajewy, J. Recent Progress in Lewis Base Activation and
Control of Stereoselectivity in the Additions of Trimethylsilyl Nucleophiles. Chem. Rev.
2008, 108, 5227–5252. DOI: 10.1021/cr800421c. (b) Karaki, F.; Ohgane, K.; Fukuda, H.;
Nakamura, M.; Dodo, K.; Hashimoto, Y. Structure–Activity Relationship Study of Non-
Steroidal NPC1L1 Ligands Identified through Cell-Based Assay Using Pharmacological
Chaperone Effect as a Readout. Bioorg. Med. Chem. 2014, 22, 3587–3609. DOI: 10.1016/j.
bmc.2014.05.022. (c) Corpet, M.; Gosmini, C. Recent Advances in Electrophilic Amination
Reactions. Synthesis 2014, 46, 2258–2271. DOI: 10.1055/s-0034-1378373.
[3] (a) Binder, W. H.; Kluger, C. Azide/Alkyne-“Click” Reactions: Application in Material
Science and Organic Synthesis. Curr. Org. Chem. 2006, 10, 1791–1815. DOI: 10.2174/
138527206778249838. (b) Moorhouse, A. D.; Moses, J. E. Click Chemistry and Medicinal
Chemistry: A Case of “Cyclo-Addition. ChemMedChem 2008, 3, 715–723. DOI: 10.1002/
cmdc.200700334. (c) Amblard, F.; Cho, J. H.; Schinazi, R. F. Cu(I)-Catalyzed Huisgen
Azide ꢂ Alkyne 1,3-Dipolar Cycloaddition Reaction in Nucleoside, Nucleotide, and
Oligonucleotide Chemistry. Chem. Rev. 2009, 109, 4207–4220. DOI: 10.1021/cr9001462.
(d) Holub, J. M.; Kirshenbaum, K. Tricks with Clicks: Modification of Peptidomimetic
Oligomers via Copper-Catalyzed Azide-Alkyne [3 þ 2] Cycloaddition. Chem. Soc. Rev.
2010, 39, 1325–1337. DOI: 10.1039/b901977b. (e) Agalave, S. G.; Maujan, S. R.; Pore, V.
S. Click Chemistry: 1,2,3-Triazoles as Pharmacophores. Chem. Asian J. 2011, 6,
2696–2718. DOI: 10.1002/asia.201100432. (f) Thirumurugan, P.; Matosiuk, D.; Jozwiak, K.
Click Chemistry for Drug Development and Diverse Chemical–Biology Applications.
€
Chem. Rev. 2013, 113, 4905–4979. DOI: 10.1021/cr200409f. (g) Jalani, H. B.; Karagoz, A.
C¸.; Tsogoeva, S. B. Synthesis of Substituted 1,2,3-Triazoles via Metal-Free Click
Cycloaddition Reactions and Alternative Cyclization Methods. Synthesis. 2017, 49, 29–41.
DOI: 10.1055/s-0036-1588904.
[4] (a) Pokhodylo, N. T.; Matiychuk, V. S.; Obushak, M. D. Synthesis of Triazoles via
Regioselective Reactions of Aryl Azides with Cyanoacetyl Pyrroles and Indoles. Synthesis
2009, 8, 1297–1300. DOI: 10.1055/s-0028-1087992. (b) Urankar, D.; Steinbu€cher, M.;
ꢀ
Kosjek, J.; Kosmrlj, J. N-(Propargyl)Diazenecarboxamides for ‘Click’ Conjugation and
Their 1,3-Dipolar Cycloadditions with Azidoalkylamines in the Presence of Cu(II).

R
SYNTHETIC COMMUNICATIONSV
7
Tetrahedron 2010, 66, 2602–2613. DOI: 10.1016/j.tet.2010.02.042. (c) Feldman, A. K.;
Colasson, B.; Fokin, V. V. One-Pot Synthesis of 1,4-Disubstituted 1,2,3-Triazoles from in
Situ Generated Azides. Org. Lett. 2004, 6, 3897–3899. DOI: 10.1021/ol048859z. (d)
Fletcher, J. T.; Reilly, J. E. Fast Dye Salts Provide Fast Access to Azidoarene Synthons in
Multi-Step One-Pot Tandem Click Transformations. Tetrahedron Lett. 2011, 52,
5512–5515. DOI: 10.1016/j.tetlet.2011.08.069. (e) Ichikawa, S.; Ueno, H.; Sunadome, T.;
Sato, K.; Matsuda, A. Tris(Azidoethyl)Amine Hydrochloride; a Versatile Reagent for
Synthesis of Functionalized Dumbbell Oligodeoxynucleotides. Org. Lett. 2013, 3, 694–697.
DOI: 10.1021/ol400001w. (f) Opsomer, T.; Thomas, J.; Dehaen, W. Chemoselectivity in
the Synthesis of 1,2,3-Triazoles from Enolizable Ketones, Primary Alkylamines, and 4-
Nitrophenyl Azide. Synthesis 2017, 49, 4191–4198. DOI: 10.1055/s-0036-1588856.
ꢁ
ꢁ
€
[5] Bu€Rglova, K.; Moitra, N.; HodacꢀOva, J.; CattoeN, X.; Wong Chi Man, M. Click
Approaches to Functional Water-Sensitive Organotriethoxysilanes. J. Org. Chem. 2011, 76,
7326–7333. DOI: 10.1021/jo201484n.
[6] For recent reviews, see: (a) Bock, V. D.; Hiemstra, H.; van Maarseveen, J. H. CuI-
Catalyzed Alkyne–Azide “Click” Cycloadditions from a Mechanistic and Synthetic
Perspective. Eur. J. Org. Chem. 2006, 2006, 51–68. DOI: 10.1002/ejoc.200500483. (b)
Meldal, M.; Tornøe, C. W. Cu-Catalyzed Azide-Alkyne Cycloaddition. Chem. Rev. 2008,
108, 2952–3015. DOI: 10.1021/cr0783479. (c) Kappe, C. O.; Van der Eycken, E. Click
Chemistry under Non-Classical Reaction Conditions. Chem. Soc. Rev. 2010, 39,
1280–1290. DOI: 10.1039/B901973C. (d) Hein, J. E.; Fokin, V. V. Copper-Catalyzed
Azide-Alkyne Cycloaddition (CuAAC) and Beyond: New Reactivity of Copper(I)
Acetylides. Chem. Soc. Rev. 2010, 39, 1302–1315. DOI: 10.1039/b904091a.
[7] (a) Sheng, W.-S.; Sheng, S.-R.; Zeng, J.-B.; Huang, Z.-Z.; Cai, M.-Z. Four-Component,
One-Pot
Synthesis
of
1,4-Disubstituted
1,2,3-Triazoles
Bearing
1-(2-
Phenylselenocyclohexyl) Group. J. Heterocycl. Chem. 2014, 51, E222–E226. DOI: 10.1002/
jhet.1972. (b) Wan, J.-P.; Hu, D.-Q.; Liu, Y.-Y.; Sheng, S.-R. Azide-Free Synthesis of 1,2,3-
Triazoles: New Opportunity for Sustainable Synthesis. ChemCatChem 2015, 7, 901–903.
DOI: 10.1002/cctc.201500001.
[8] Ji, W.-Q.; Li, P.-H.; Yang, S.; Wang, L. Visible-Light-Induced Oxidative Formylation of N-
alkyl-N-(Prop-2-yn-1-yl)Anilines with Molecular Oxygen in the Absence of an External
Photosensitizer. Chem. Commun. 2017, 53, 8482–8485. DOI: 10.1039/C7CC03693K.
[9] Siddiki, A. A.; Takale, B. S.; Telvekar, V. N. One Pot Synthesis of Aromatic Azide Using
Sodium Nitrite and Hydrazine Hydrate. Tetrahedron Lett. 2013, 54, 1294–1297. DOI: 10.
1016/j.tetlet.2012.12.112.