Lanthanum loaded CuO nanoparticles: synthesis and characterization of a recyclable catalyst for the synthesis of 1,4-disubstituted 1,2,3-triazoles and propargylamines

Article abstract of DOI:10.1039/c5ra05468k

Lanthanum loaded CuO (LCO) nanoparticles (NPs) were successfully synthesized by a precipitation-thermal decomposition method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS) and BET surface area measurements. The synthesized LCO NPs were used as a nanocatalyst for the synthesis of 1,4-disubstituted 1,2,3-triazoles by a click reaction of substituted benzyl azides and alkynes and the synthesis of propargylamines via three-component coupling reactions of aldehydes, alkynes and amines under ultrasonication. The one-pot operation, atom-economical nature, regioselectivity and good yields are the noteworthy features of this protocol. The reusability of the prepared nanocatalyst was successfully examined six times without any appreciable loss in catalytic activity.

Full text of DOI:10.1039/c5ra05468k

View Article Online
View Journal
RSC Advances
This article can be cited before page numbers have been issued, to do this please use: K. Kesavan, S.Kutti
Rani, D. Easwaramoorthy and S. Ramalingam, RSC Adv., 2015, DOI: 10.1039/C5RA05468K.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. This Accepted Manuscript will be replaced by the edited,
formatted and paginated article as soon as this is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/advances

Page 1 of 10
RSC Advances
Dynamic Article Links ►
Journal Name
View Article Online
DOI: 10.1039/C5RA05468K
Cite this: DOI: 10.1039/c0xx00000x
www.rsc.org/xxxxxx
ARTICLE TYPE
Lanthanum loaded CuO nanoparticles: Synthesis, characterization and
recyclable catalyst for the synthesis of 1, 4ꢀ disubstituted 1, 2, 3ꢀtriazoles
and propargylamines
R. Sasikala, S. Kutti Rani,* D. Easwaramoorthy and K. Karthikeyan*
5
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
DOI: 10.1039/b000000x
The Lanthanum loaded CuO (LCO) nanoparticles (NPs) were successfully synthesized by precipitationꢀ
thermal decomposition method and characterized by Xꢀray diffraction (XRD), field emission scanning
electron microscopy (FESEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS),
10 photoluminescence (PL), Xꢀray photoelectron spectroscopy (XPS) and BET surface area measurements.
The synthesized LCO NPs was used as nanocatalyst for the synthesis of 1, 4ꢀdisubstitutedꢀ1, 2, 3ꢀtriazoles
by click reaction of substituted benzyl azides and alkynes and synthesis of propargylamines via threeꢀ
component coupling reaction of aldehydes, alkynes and amines under ultrasonication. Oneꢀpot operation,
atomꢀeconomical nature, regioselectivity and good yields are the noteworthy features of this protocol. The
15 reusability of the prepared nanocatalyst was successfully examined six times without any appreciable loss
in catalytic activity.
research in this area has concentrated on heterogeneous catalytic
systems, which have several advantages, such as faster and
simpler isolation of the reaction products by filtration, as well as
recovery and recycling of the catalyst systems. Thus, the particles
50 of copper20 or its oxide derivatives,21 copper salts supported on
charcoal22 or on organic materials,23 as well as on inorganic
supports24 have been tested for this transformation.
Introduction
During the last few decades, great attention has been given to
click1 and green chemistry2 for the development of efficient and
20 environmentally benign protocols. Recently nanoꢀparticles and
nanoparticles supported on a metal oxide have emerged as a
sustainable and competitive alternative to conventional catalysis,
and have been extensively studied in the field of medicine for
drug delivery systems.3,4 Mesoporous nanoꢀmaterials have also
25 gained increasing importance in their use as catalysts in various
organic reactions,5 as sensors for the detection of hydrazine,6 in
optoelectronics7,8 and as electron transfer mediators in bioꢀ
electrochemical systems.9
1, 2, 3ꢀTriazoles are important subꢀunits in heterocyclic chemistry
30 because of their unique structure, chemical and biological
properties.10 Huisgen 1,3ꢀdipolar azideꢀalkyne cycloaddition is
traditionally applied for accessing 1,2,3ꢀtriazoles.11 However, the
major limitations of this nonꢀcatalyzed process are the
requirement of high temperature and poor regioselectively giving
35 a mixture of 1,4ꢀ and 1,5ꢀdisubstituted triazoles. Up to now,
several efforts to control the 1,4ꢀ versus 1,5ꢀregioselectivity have
been reported.12 As a prototype for click chemistry,13 the recent
advance in Cu(I)ꢀcatalyzed azideꢀalkyne cycloaddition (CuAAC)
reported by Sharpless14 and Meldal15 to access 1,2,3ꢀtriazoles in
40 short reaction times under mild conditions and as only one 1,4ꢀ
regioisomer.16ꢀ19 The major limitations of existing CuAAC
protocols realized in terms of homogeneous nature of catalysts,
thus creating problem during separation of catalyst/product(s),
and the requirement of adding reducing agents and stabilizing
45 ligands limited their utilization for practical processes. Recent
Furthermore, Propargylamines are key intermediates for the
synthesis of natural products and nitrogen containing biologically
55 active compounds.25 Recently, propargylamines are prepared by
transition metalꢀcatalyzed A3coupling reactions of aldehydes,
alkynes and amines. A3coupling reactions have received much
attention due to their simple operation and high efficiency, which
employ amines as nitrogen sources. Several homogenous
60 catalysts like nickel26a and copper salts,26b CuI/ligand,26c and
heterogeneous systems such as Ag(I),27a and Cu(I),27b in ionic
liquids, silicaꢀimmobilized CuI,27c Cu(0)ꢀnanoparticles on
montmorillonite,27d
CuNPs/MagSilica,
copper
ferrite
nanoparticles,27e
27f
27h
AuꢀSBA27g and AuꢀCeO2
have been
65 developed for propargylamines synthesis.
On the other hand, ultrasound irradiation has been well
established energy source to promote chemical reactions.28 Many
homogeneous and heterogeneous reactions can be conducted
smoothly by sonication under milder conditions and shorter
70 reaction times to afford improved yields and increased
selectivities.29 Ultrasound irradiation has some potential effects
on a heterogeneous catalytic system like increase of active
catalyst surface area, promotion of cavitation bubble formation,
and removal of impurities deposited on the catalyst.30, 31
75 Modern research has been focused on finding new catalysts to
improve the efficiency of these azideꢀalkyne cycloaddition and
This journal is © The Royal Society of Chemistry [year]
[journal], [year], [vol], 00–00 | 1

RSC Advances
Page 2 of 10
View Article Online
DOI: 10.1039/C5RA05468K
A3 coupling reactions. As the above mentioned methods are not
morphology is much better than CuO NPs morphology.
compatible with heat sensitive substrates and there is a need to
develop an effective synthesis of triazoles and propargylamines
employing more ecoꢀfriendly catalyst. In this view, we wish to
describe a heterogeneous lanthanum loaded CuOꢀcatalyzed for
the synthesis of 1, 4ꢀdisubstitutedꢀ1, 2, 3ꢀtriazole and
propargylamine derivatives under ultrasonication.
5
Results and discussion
Catalyst preparation and characterization
10 The LCO NPs was prepared by
a precipitation thermal
decomposition method. Two aqueous solutions of copper nitrate
and oxalic acid were separately brought to their boiling points.
The oxalic acid solution was added to the copper nitrate solution,
copper oxalate was precipitated, then La(NO3)3 solution was
15 mixed with the copper oxalate suspension and stirred for 1 h at
60−70 °C. After the mixture has cooled to room temperature, Laꢀ
containing copper oxalate was washed with distilled water, air
dried for overnight and dried at 100 °C for 5 h. Calcination of the
mixed precipitate at 450 °C for 5 h results in the decomposition
20 of copper oxalate to CuO NPs. The Laꢀloaded CuO NPs was
obtained after the sample was cooled to room temperature. The
bare CuO NPs was prepared without addition of La(NO3)3 by the
above procedure.
55
Figure 1. XRD patterns of a) bare CuO and b) LCO NPs (The
insert figure shows magnification of XRD patterns of
(a) bare CuO and (b) LCO NPs)
The prepared LCO NPs was characterized by XRD, FEꢀSEM,
25 EDS, DRS, PL, XPS and BET surface area measurements. The
crystalline nature of the bare CuO NPs was identified from their
corresponding powder XRD patterns (Fig. 1a). All the
diffractions were well matched with monoclinic phase of CuO
NPs (standard JCPDS File No: 048ꢀ1548) and diffraction peaks
30 2θ are 35.45°, 38.73°, 42.50°, 48.92°, 61.99° and 66.49°
corresponding to (002), (111), (200), (202), (220) and (113) plane
of monoclinic phase of CuO NPs.32 In XRD spectrum of LCO
NPs (Fig. 1b), there was no new peak appearing and the peaks
are slightly broadening due to reduction in the particles size when
35 compared to bare CuO NPs. Insert figure (Fig. 1) infers that the
peak corresponding to LCO NPs was slightly shifted to lower
angle, which revealed that the La loaded on the surface of CuO
material.33 The crystalline size of LCO and CuO NPs were
determined using DebyeꢀScherrer equation.
60
Figure 2. FEꢀSEM images of a) CuO (3ꢁm) and b) LCO NPs (3ꢁm).
The EDS spectra of the bare CuO and LCO NPs were depicted in
Fig. 3, the presence of Cu and O in the bare CuO and La, Cu, O
in the LCO NPs. This indicates clearly that the La ions were
65 successfully loaded on the surface of CuO NPs.
(b)
K λ
β cos θ
D =
40 Where D is the crystal size of the catalyst, K is dimensionless
constant, λ is the wavelength of Xꢀray, β is the full width at halfꢀ
maximum (FWHM) of the diffraction peak and θ is the
diffraction angle. From this equation, we obtained the crystalline
size of LCO NPs (19 nm) and was found to be lower than the
45 bare CuO NPs (25 nm).
(a)
The FEꢀSEM images of CuO and LCO NPs represent (Fig. 2)
that the particles are in nanometer region which is in agreement
with grain size based on Scherrer’s formula. Fig. 2(a) shows the
almost uniform formation of spherical shaped CuO (3ꢁm)
50 particle. In addition, it has more gaps between the two spherical
shaped CuO NPs. The LCO NPs (3ꢁm) exhibit agglomerate
formations (Fig. 2(b)) and reveal that the nonꢀuniform formation
of spherical shaped nanoparticles. It explains LCO NPs
Figure 3. EDS of a) bare CuO and b) LCO NPs.
2
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 3 of 10
RSC Advances
View Article Online
DOI: 10.1039/C5RA05468K
30 rule out the possibility of the existence of a Cu2O phase.34 The O
1s core level XPS signal is presented in Fig. 6b. The peak at
binding energy value of 529.0 eV is due to the oxygen in the CuO
(The O 1s signal for Cu2O is generally found at 530.5 ±0.2 eV in
the literature).36 Fig. 6d which shows that the binding energy of
35 La 3d5/2 and La 3d3/2 are 835.0 and 851.5 eV, respectively.37 The
XPS data revealed that La exist in LCO NPs as La2O3 only and
not as hydroxide or carbonate from the following evidence. The
binding energy of O 1s at 529.0 eV which is characteristic for O2ꢀ
(The O 1s signal for hydroxide and carbonate appeared at 531.6
40 eV in the literature).41 The XPS analysis of bare CuO NPs
revealed that the oxidation state of Cu is +2.
The diffuse reflectance spectra (DRS) of pure CuO and LCO NPs
are depicted in Fig. 4. La3+ might covalently interact with CuO
and slightly reduce its band gap of LCO NPs. There is no
significant change of absorption in the UV region but LCO NPs
have higher absorption than bare CuO NPs in the visible region.
Photoluminescence (PL) occurs due to the recombination of
electron–hole pair in the semiconductor. PL (Fig. 5) spectra
reveal that the PL intensity of LCO NPs is less than CuO NPs.
This is because of the suppression of recombination of the photo
5
10 generated electron–hole pairs by the La loaded on CuO.
Inhibition of the electron–hole recombination makes this catalyst
more active.
40
35
(a)
30
25
20
15
(b)
10
5
200
400
600
800
Wavelength (nm)
Figure 4. DRS of a) bare CuO and b) LCO NPs.
80
Fig. 6. XPS spectrum of LCO NPs: (a) C 1s peak, (b) O 1s peak,
(c) Cu 2p peak, and (d) La 3d peak.
(a)
50
45
In general, the surface area of the catalyst was most important
factor influencing the catalytic activity. The BET surface area
analysis of bare CuO and LCO NPs were determined by using N2
gas adsorption method. The BET surface area of LCO NPs (4.26
50 m2 g−1) was higher than the bare CuO NPs (1.82 m2 g−1). This is
according to the IUPAC classifications of type IV isotherms with
type H1 hysteresis. Type H1 hysteresis indicates that for spherical
pores, the pore opening was smaller than the diameter of the main
cavity. As the desorption portion of the isotherms moves from
55 higher partial pressure to lower partial pressure, a gradual
decrease in pore volume was observed. The BET surface and
pore volume of bare CuO and LCO NPs are given in Table 1.
(b)
40
30
20
10
0
280
330
380
430
480
530
Wavelength (nm)
15
Figure 5. Photoluminescence spectra of a) bare CuO and b) LCO NPs.
Table 1. Surface properties of the catalysts.
The elemental composition and oxidation states of the CuO NPs
and LCO NPs were analyzed using XPS. The binding energies
obtained in the XPS analysis were corrected for specimen by
20 referencing the C 1s to 284.0 eV (Fig 6a). A selected area scan
for the individual elements in LCO NPs (O 1s, Cu 2p, and La 3d)
are shown in Figure 6b, c, d, respectively. The Cu 2p core level
spectrum (Fig. 6c) represents two peaks located at 932.0 and
Properties
BET surface area
Total pore volume (single
point)
Bare CuO
1.82 (m2 g−1)
0.01 (cm3 g−1)
LCO
4.26 (m2 g−1)
0.04 (cm3 g−1)
60 The catalytic activity of synthesized LCO NPs was tested in two
different terminalꢀalkyne transformations: the 1, 3ꢀdipolar
cycloaddition of terminal alkynes with azide and the three
component synthesis of propargylamines from aldehydes, amines
and terminal alkynes (A3 coupling). The optimal reaction
65 conditions were determined independently for both reactions
studied.
953.7 eV which corresponds to the Cu 2p3/2 and Cu 2p1/2
,
25 respectively. These values match well with the data reported for
the Cu 2p in CuO.34 In addition, the shakeꢀup satellite peaks
located at 940.8 eV and 960.5 eV are characteristic of materials
having a d9 configuration.35 The strong shakeꢀup satellites
recorded in the LCO NPs confirm the Cu2+oxidation state and
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 3

RSC Advances
Page 4 of 10
View Article Online
DOI: 10.1039/C5RA05468K
Click reaction based synthesis of 1, 4ꢀ disubstituted 1, 2, 3ꢀ
triazole.
methanol: water, ethanol: water, tꢀbutanol: water and acetonitrile:
water gave 93ꢀ95% of yield (Table 2, entry 11ꢀ14). Inspired by
the observed determinant effect of water and polar protic solvents
25 on the reaction, we further investigated the feasibility of using
water as the solvent for this reaction. As we expected, the
reaction progressed very well and 99% yield was obtained under
identical condition (Table 2, entry 15). It should be noted that
the model reaction in CuO NPs gave only 65% of yield (Table 2,
30 entry 20), It revealed that the La in La loaded CuO increases the
yield of the reaction. Further investigation revealed that the result
was affected by the amount of catalyst. The catalyst loading
varied from 3 to 30 mg (Table 2, entry 16ꢀ19), the maximum
yield was obtained when 10 mg catalyst was used. Above 10 mg
35 of the catalyst, no significant change in the conversion occurred
(Fig. 7). Performing model reaction in H2O not only offers a high
reaction yield, but also avoids: (i) generation of toxic wastes (ii)
the use of large amount of organic solvent (iii) tedious post
treatment. Therefore, our methodology is an attractive strategy
40 for the synthesis of the target compound from the view point of
green synthesis.
We started our study by examining the model reaction of benzyl
azides and phenyl acetylene which afforded 1ꢀbenzylꢀ4ꢀphenylꢀ
1Hꢀ1, 2, 3ꢀtriazole (3a). Initially, the reaction was investigated
using various catalysts and solvents (Table 2) with a view to
finding optimal conditions to maximize the yield of the product.
The reaction in the absence of catalyst in water under room
temperature and sonication failed to afford the product (Table 2,
10 entry 1, 2). Then we used LCO NPs as heterogeneous catalyst to
carry out azide cycloaddition. Under grinding, the triazole was
obtained as a sole product with 30% yield (Table 2, entry 3) and
the product was confirmed by NMR spectrum analysis. When the
same reaction was performed using ultrasonic irradiation without
15 solvent that increased the yield up to 40% (Table 2, entry 4).
Further optimization was carried out in different organic solvents
such as toluene and DMF gave yields of 30% and 15% (Table 2,
entry 5, 6) respectively. While the reaction proceeded moderately
in acetonitrile (Table 2, entry 7), a huge improvement was
20 observed in polar protic solvents (82ꢀ85 %), (Table 2, entry 8ꢀ
10) and combination of polar protic solvents with water such as
5
Table 2. Optimization of azideꢀalkyne cycloaddition.
Ph
Catalyst
Solvent
N3
N
Ph
+
N
N
1a
2a
3a
Entry
Condition
Catalyst
Weight % of
catalyst (mg)
Solvent
Time
(min)
Yield (%)a
1
2
3
4
5
6
7
8
RT stirring
Sonication
Grinding
ꢀ
ꢀ
ꢀ
ꢀ
Water
Water
Without solvent
Solvent free
Toluene
Dimethylformamide
Acetonitrile
Methanol
17h
60
60
60
30
30
30
30
30
30
15
15
15
30
15
15
15
15
15
30
ꢀ
ꢀ
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
LCO
CuO
10
10
10
10
10
10
10
10
10
10
10
10
10
3
30
40
30
15
65
85
85
82
95
95
93
95
99
94
97
98
98
65
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
Sonication
9
Ethanol
tꢀbutanol
10
11
12
13
14
15
16
17
18
19
20
Methanol : water
Ethanol : water
tꢀbutanol : water
Acetonitrile : water
Water
Water
Water
Water
Water
7.5
15
30
10
Water
45 a Isolated yield
4
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 5 of 10
RSC Advances
Dynamic Article Links ►
Journal Name
View Article Online
DOI: 10.1039/C5RA05468K
Cite this: DOI: 10.1039/c0xx00000x
www.rsc.org/xxxxxx
ARTICLE TYPE
20 Table 3. Synthesis of 1, 4ꢀdisubstituted 1, 2, 3ꢀtriazoles with different
alkynes and azides.
R1
LCO NPs/ Water
R1
R
N
N
+
R
N3
Sonication/ 15 min
N
3a-n
1a-g
2a-h
Yield
(%)a
99
Entry
1
Alkyne
Ph
Azide (R)
Product
C6H5, 1a
3a
2a
O2N
O
2
3
1a
1a
3b
3c
96
97
2b
CHO
Fig. 7: Effect of catalyst loading for the synthesis of 1, 4ꢀdisubstitued
1,2,3ꢀtriazole under ultrasonication method.
O
2c
With these results in hand, we further investigate the substrate
scope and the results are presented in Table 3. Many azides
including 4ꢀnitro benzyl, 4ꢀmethoxy benzyl, 4ꢀchloro benzyl, 2ꢀ
thiophenyl methyl, nꢀoctyl and nꢀhexyl react with various
terminal alkynes and afford the corresponding products in good
to excellent yields (Table 3, entry 1ꢀ9 and 11ꢀ14). The reaction
10 condition is also applicable to internal alkyne to afford the
corresponding product with moderate yield (Table 3, entry ꢀ10).
The reusability of the catalyst was checked six times without any
treatment (Table 4) and found that there is no appreciable loss in
the yield (Fig.8).
H3C
5
O
4
5
1a
1a
3d
3e
90
87
2d
O
N
2e
O
15
N
O
6
1a
3f
89
2f
2a
2a
2a
7
8
9
4ꢀNO2C6H4, 1b
4ꢀOCH3C6H4, 1c
4ꢀClC6H4, 1d
3g
3h
3i
93
97
95
Ph
Ph
10
1a
3j
65
2g
2a
2a
2a
11
12
13
2ꢀthiophenyl, 1e
CH3(CH2)6, 1f
CH3(CH2)4, 1g
3k
3l
3m
82
87
91
COOEt
2h
14
1a
3n
88
aIsolated yield
25 Table 4. Reusability of catalyst LCO NPs.a
Run
1
99.4
2
98.6
3
98.1
4
95.9
5
95.4
6
94.0
Fig. 8: Reusability of catalyst for the synthesis of 1, 4ꢀdisubstitued 1, 2,
Yieldb
3ꢀtriazole under ultrasonication method.
a Reaction condition: benzyl azide (1eqiv.), phenyl acetylene (1.5 eqiv.),
LCO NPs (10mg) and 5mL H2O.
bIsolated yield.
By analogy with previous reports, the synthesis involves stepwise
30 mechanism (Scheme 1). First step, the LCO NPs coordinate with
alkyne 2 to form copper acetylide (2ʹ) followed by coordination
of the organic azide 1 in the second step. The coordination event
This journal is © The Royal Society of Chemistry [year]
[journal], [year], [vol], 00–00 | 5

RSC Advances
Page 6 of 10
View Article Online
DOI: 10.1039/C5RA05468K
is synergistic for both reactive partners. Coordination of the azide
reveals the βꢀnucleophilic, vinylideneꢀlike properties of the 30 expanded with a variety of aldehydes and amines and these
The scope of this LCO NPs catalyzed A3 coupling was further
acetylide, whereas the azide's terminus becomes more
electrophilic, and a strained copper triazolide (3ʹ) is formed.
Protonation of the triazole–copper derivative followed by
dissociation of the product 3 completes the reaction and
regenerates the catalyst.
results were summarized in Table 6. The reactions proceeded
well to obtain products in encouraging yields. Electron donating
substituents like methyl, as well as methoxy group at para
position (Table 6, entries 2,3 and 7,8) and electron withdrawing
35 chlorine and bromine atom at the para position of aldehyde
(Table 6, entries 4,5 and 9,10) did not induce appreciable
changes in the reaction efficiency. In the presence of NO2 group
at para position of the aldehyde no product was isolated. (Table
6, entry 6).
5
H+
R1
2
Step 1
R1
R1
40 Table 6. Substrate scope of different aldehydes and amines.
2'
N
3
N
N
X
R
R
N3
Step 2
Step 4
1
N
H
LCO NPs
Toluene
CHO
X
R1
H+
R1
+
+
R2
N
H
Ph
Sonication
15 min
R2
Ph
6
Step 3
N
N
N
N N
4a-f
7a-j
N
X = O, 5a
= CH2, 5b
R
R
3'
1'
Yielda
Entry
Aldehyde, R2
Amine
Product
Scheme 1. Tentative mechanism for click reaction using LCO NPs
(%)
98
90
92
94
92
ꢀb
95
89
92
90
10
catalyst.
1
2
3
4
5
6
7
8
9
H, 4a
CH3, 4b
OCH3, 4c
Br, 4d
Cl, 4e
NO2, 4f
4b
5a
5a
5a
5a
5a
5a
5b
5b
5b
5b
7a
7b
7c
7d
7e
7f
7g
7h
7i
A3 coupling reaction based oneꢀpot synthesis of
propargylamines.
The catalytic activity of the LCO NPs was also examined in the
synthesis of propargylamines, the reaction of benzaldehyde,
15 morpholine and phenylacetylene were examined and the results
are presented in Table 5. Among the various solvents and
solvent/coꢀsolvent mixtures, toluene was found to be the most
effective medium for this transformation (Table 5, entry 7).
After finding the best solvent, amount of catalyst (Table 5, entry
20 8ꢀ11) was optimized. The highest yield of propargylamines was
achieved when 10 mg catalyst in toluene was used (Table 5,
entry 7). The low yield was obtained when the bare CuO NPs
used as catalyst (Table 5, entry 12) and it clearly demonstrates
the effect of LCO NPs in this reaction.
4c
4d
4e
10
7j
a Isolated yield.
b No reaction.
O
X
H
+
N
R2
H
25 Table 5. Effect of solvent on A3 coupling reaction.
5
4
O
X
N
H
N
A
O
CHO
Catalyst
+
+
H
Solvent,
Sonication
15 min
Ph
N
H
R2
Ph
6
B
H
7a
4a
5a
Entry
Catalyst (mg)
Solvent
Yield (%)a
X
N
1
2
3
4
5
6
7
8
9
LCO (10)
LCO (10)
LCO (10)
LCO (10)
LCO (10)
LCO (10)
LCO (10)
LCO (3)
LCO (7.5)
LCO (15)
LCO (30)
CuO (10)
Water
Ethanol
Methanol
DCM
40b
30
45
40
15
58
98
93
95
98
98
60
Ph
R2
DMF
7
CH3CN
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
H
6
45
Scheme 2. Tentative mechanism of A3 coupling reaction using LCO
10
11
12
catalyst.
A tentative mechanism (Scheme 2) is proposed for the probable
sequence of events involving the activation of the CꢀH bond of
50 alkyne (6) by LCO NPs. The Cuꢀacetylide intermediate (A)
a Isolated yield
b reaction time 1h
6
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 7 of 10
RSC Advances
View Article Online
DOI: 10.1039/C5RA05468K
55 Preparation of LCO nano particles.
generated by the reaction of acetylene and LCO reacts with
iminium ion (B), formed in situ by condensation of aldehyde with
secondary amine to afford desired propargylamines (7), and the
catalyst is generated.
The Laꢀloaded CuO NPs was prepared by a precipitation thermal
decomposition method. Aqueous solutions consisting of copper
nitrate and oxalic acid in deionized water were separately brought
to their boiling points. When the oxalic acid solution was added
60 to solution of copper nitrate, copper oxalate was precipitated.
Then, La(NO3)3 solution was mixed with the solution of copper
oxalate suspension and then stirred for 1 h at 60−70 °C. After the
mixture had cooled to room temperature, La containing copper
oxalate was washed with distilled water, air dried overnight, and
65 dried at 100 °C for 5 h. Calcination of the mixed precipitate at
450 °C for 5 h decomposed copper oxalate to CuO. The Laꢀ
loaded CuO obtained after the sample had cooled to room
temperature. The bare CuO was prepared without addition of
5
Conclusions
We have developed an efficient La loaded CuO nanoparticles as
heterogeneous catalyst for the synthesis of 1,4ꢀdisubstitutedꢀ
1,2,3ꢀtriazole by click reaction of azide and alkyne and propargyl
amine by A3 coupling reaction of aldehyde, secondary amine and
10 terminal alkynes under ultrasonic irradiation. In this method, the
catalyst was collected easily by filtration and the reusability of
the prepared nanocatalyst was successfully examined over six
times and was found to be effective with only a very slight loss of
catalytic activity. This protocol is a clean and safe process, and
15 can be used to generate a diverse range of product in good to
excellent yields.
La(NO3)3 by the above procedure.
70 General Procedure for the Synthesis of 1,4ꢀDisubstituted
1,2,3ꢀTriazoles (3aꢀj)
The heterogeneous LCO NPs (10 mg) was added to a mixture of
azide (1 mmol) and alkyne (1.5 mmol) in 5ml of water. The
solution was subjected to ultrasonic irradiation for particular time
75 duration. The progress of the reaction was monitored by TLC
(20% ethyl acetate/hexane). When the reaction was complete, the
catalyst was removed by centrifugation. The filtrate was extracted
with ethyl acetate (3x 10 ml). The combined organic solutions
were dried with Na2SO4.The pure products were isolated without
80 column purification only by the process of crystallization.
1ꢀbenzylꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3a):39a White solid; Mp =
Notes
Department of Chemistry, B. S. Abdur Rahman University, Vandalur,
Chennai-600 048, India. Fax: +91-44-22750520; Tel: +91 44-22750520;
20 E-mail: karthiclri@gmail.com, skrani@bsauniv.ac.in.
† Electronic Supplementary Information (ESI) available: 1H and 13C
NMR spectrum of all compounds. See DOI: 10.1039/b000000x/
Experimental section
1
All chemicals were obtained from SigmaꢀAldrich Company and
25 used as received. All azides were prepared as per the procedure
reported earlier.38 All the solvents and aldehydes were used after
distillation. Melting points were measured on Guna melting point
apparatus and are uncorrected. NMR spectra were obtained on a
118ꢀ120 °C; Rf = 0.58 (30 % Ethylacetate: nꢀhexane); H NMR
(400 MHZ, CDCl3): δH 7.80 (d, J = 7.6 Hz, 2H), 7.66 (s, 1H),
7.42ꢀ7.38 (m, 5H), 7.32ꢀ7.30 (m, 3H), 5.58 (s, 2H); 13C NMR
85 (100 MHz, CDCl3): δc 149.0, 134.7, 130.5, 129.2, 128.8, 128.2,
128.1, 125.7, 119.5, 54.3.
4ꢀ((4ꢀnitrophenoxy) methyl)ꢀ1ꢀbenzylꢀ1Hꢀ1, 2, 3ꢀtriazole (3b):
Yellow solid; Mp = 94ꢀ96 °C; Rf = 0.2 (30 % Ethylacetate: nꢀ
Bruker Avance 400 NMR Spectrometer (1H NMR: 400 MHz; 13
C
1
hexane); H NMR (400 MHZ, CDCl3): δH 8.19 (d, J = 8.8 Hz,
30 NMR: 100 MHz). Analytical TLC was carried out with Merck
plates precoated with silica gel 60 F254 (0.25 mm thick). Mass
spectra were recorded on a JEOL GC Mate using electron impact
ionization (EI) techniques. The mass were analyzed by using a
Electrospray Ionisation Method with Thermo Finnigan Mass
35 spectrometer. Elemental analyses were recorded using a Thermo
Finnigan FLASH EA 1112 CHN analyzer. Powder Xꢀray
diffraction patterns were obtained using X′Per PRO
diffractometer equipped with a CuKα radiation (wavelength
1.5406 Å) at 2.2 kW Max. Peak positions were compared with
40 the standard files to identity the crystalline phase. The
morphology of the catalyst was examined using a JEOL JSMꢀ
6701F cold field emission scanning electron microscope (FEꢀ
SEM). The specific surface areas of the samples were determined
through nitrogen adsorption at 77 K on the basis of BET equation
45 using a micrometrics ASAP 2020 V3.00 H. Diffuse reflectance
90 2H), 7.56 (s, 1H), 7.40ꢀ7.38 (m, 3H), 7.30ꢀ7.26 (m, 2H), 7.06 (d,
J = 8.8 Hz, 2H), 5.55 (s, 2H), 5.27 (s, 2H); 13C NMR (100 MHz,
CDCl3): δc 163.1, 141.9, 134.2, 129.2, 128.9, 128.2, 125.9, 122.9,
114.9, 62.5, 54.4; HRMS: calculated for C16H14N4O3 Mw:
310.1066, found: 310.1062.
95 2ꢀ((1ꢀbenzylꢀ1Hꢀ1, 2, 3ꢀtriazoleꢀ4ꢀyl) methoxy) benzaldehyde
(3c): White solid; Mp = 130ꢀ132 °C; Rf = 0.23 (30 %
1
Ethylacetate: nꢀhexane); H NMR (400 MHz, CDCl3): δH 10.42
(s, 1H), 7.83 (d, J = 7.6 Hz , 1H), 7.58 (s, 1H), 7.54 (d, J = 8.0
Hz, 1H), 7.39ꢀ7.37 (m, 3H), 7.29ꢀ7.27 (m, 2H), 7.16 (d, J = 8.4
100 Hz, 1H), 7.06 (t, J = 7.6 Hz, 1H), 5.56 (s, 2H), 5.32 (s, 2H); 13C
NMR (100 MHz, CDCl3): δc 189.6, 160.5, 135.9, 134.3, 129.2,
128.9, 128.7, 128.1, 125.1, 121.4, 113.1, 62.6, 54.4; HRMS:
calculated for C17H15N3O2 Mw: 293.1164, found: 293.1162.
4ꢀ((pꢀtolyloxy)methylꢀ1ꢀbenzylꢀ1Hꢀ1, 2, 3ꢀtriazole (3d): White
105 solid; Mp = 96ꢀ98 °C; Rf = 0.48 (30 % Ethylacetate: nꢀhexane);
1H NMR (400 MHz, CDCl3): δH 7.52 (s, 1H), 7.37ꢀ7.35 (m, 3H),
7.27ꢀ7.25 (m, 2H), 7.06 (d, J = 8.0 Hz, 2H), 6.85 (d, J = 8.8 Hz,
2H), 5.51 (s, 2H), 5.15 (s, 2H), 2.27 (s, 3H); 13C NMR (100 MHz,
CDCl3): δc 156.1, 134.5, 130.5, 129.9, 129.2, 128.8, 128.1, 122.7,
110 114.7, 62.3, 54.3, 20.5; MS m/z = 280 M++1; Anal. Calcd for
C17H17N3O (279.14): C, 73.10; H, 6.13; N, 15.04. Found: C,
73.18; H, 6.06; N, 15.14.
spectra
were
recorded
using
Shimadzu
UVꢀ2450.
Photoluminescence (PL) spectra at room temperature were
recorded using a Perkin Elmer LS 55 fluorescence spectrometer.
The nanoparticles were dispersed in carbon tetrachloride and
50 excited using light of wavelength 300 nm. Xꢀray photoelectron
spectra of the catalysts were recorded in an ESCAꢀ3 Mark II
spectrometer (VG Scientific Ltd., England) using Al Kα (1486.6
eV) radiation as the source. Spectra were referenced to the
binding energy of C1s (284 eV).
4ꢀ((1ꢀbenzylꢀ1Hꢀ1, 2, 3ꢀtriazoleꢀ4ꢀyl)methyl)morpholine (3e):
Orange solid; Mp = 66ꢀ68 °C; Rf = 0.11 (30 % Ethylacetate: nꢀ
115 hexane); 1H NMR (400 MHz, CDCl3): δH 7.39ꢀ7.36 (m, 4H),
7.28ꢀ7.26 (m, 2H), 5.51 (s, 2H), 3.70ꢀ3.68 (m, 4H), 3.64 (s, 2H),
2.51ꢀ2.48 (m, 4H); 13C NMR (100 MHz, CDCl3): δc 144.5,
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 7

RSC Advances
Page 8 of 10
View Article Online
DOI: 10.1039/C5RA05468K
13C NMR (100 MHz, CDCl3): δc 157.3, 137.1, 134.0, 127.7,
65 127.4, 126.9, 126.8, 60.8, 52.3, 13.1.
General procedure for the synthesis of propargylamine
derivatives (7aꢀj):
In a 25 mL glass vial, a mixture of benzaldehydes 4aꢀj (1mmol),
134.6, 129.1, 128.8, 128.1, 122.5, 66.8, 54.2, 53.7, 53.4; MS m/z
= 259 M++1; Anal. Calcd for C14H18N4O (258.15): C, 65.09; H,
7.02; N, 21.69. Found: C, 65.02; H, 7.05; N, 21.75.
1ꢀ((1ꢀbenzylꢀ1Hꢀ1, 2, 3ꢀtriazoleꢀ4ꢀyl) methyl) indolineꢀ2,3ꢀ
5
dione (3f): Orange solid; Mp = 134ꢀ136 °C; Rf = 0.12 (30 %
1
Ethylacetate: nꢀhexane); H NMR (400 MHz, CDCl3): δH 7.60ꢀ
amine 5a, 5b (1.2 mmol), phenylacetylene 6 (1.5 mmol) and LCO
70 nanoparticles (10 mg) in 5mL toluene, were sonicated for 30 min.
The progress of the reaction was monitored by TLC (20% ethyl
acetate/hexane). After completion of the reaction, the catalyst was
removed by centrifugation. The reaction mixture was extracted
with ethyl acetate (3×10 mL). The combined organic phases were
75 dried with Na2SO4, filtered, concentrated, and the residue was
purified by flash chromatography on silica gel (elutant:
hexane/ethyl acetate, 3:1, v/v).
7.56 (m, 2H), 7.52 (s, 1H), 7.37ꢀ7.35 (m, 2H), 7.32 (d, J = 8.0 Hz,
1H), 7.25ꢀ7.23 (m, 2H), 7.11 (t, J = 7.2 Hz, 1H), 5.48 (s, 2H),
4.99 (s, 2H); 13C NMR (100 MHz, CDCl3): δc 183.1, 157.9,
10 150.2, 142.1, 138.6, 134.0, 129.2, 129.0, 128.3, 125.3, 124.0,
122.8, 117.5, 111.6, 54.4, 35.4. HRMS: calculated for
C18H14N4O2 Mw: 318.1117, found: 318.1115.
1ꢀ(4ꢀnitrobenzyl)ꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3g):39b White
solid; Mp = 114ꢀ116 °C; Rf = 0.25 (30 % Ethylacetate: nꢀ
15 hexane); 1H NMR (400 MHz, CDCl3): δH 8.26ꢀ8.23 (m, 2H), 7.82
(d, J = 6.8, 2H), 7.75 (s, 1H), 7.46ꢀ7.40 (m. 4H), 7.36ꢀ7.32 (m,
1H), 5.70 (s, 2H). 13C NMR (100 MHz, CDCl3): δc 148.1, 141.7,
130.1, 128.9, 128.6, 128.5, 125.8, 124.4, 119.7, 53.2.
4ꢀ(1,3ꢀdiphenylpropꢀ2ꢀynꢀ1ꢀyl)morpholine (7a):40a,b Viscous
liquid; 1H NMR (400 MHZ, CDCl3): δH 7.64ꢀ7.62 (m, 2H), 7.53ꢀ
80 7.50 (m, 2H), 7.39ꢀ7.24 (m, 6H), 4.79 (s, 1H), 3.78ꢀ3.69 (m, 4H),
2.64ꢀ2.62 (m, 4H); 13C NMR (100 MHz, CDCl3): δc 137.8,
131.8, 128.6, 128.3, 128.28, 128.2, 127.8, 123.0, 88.5, 85.1, 67.2,
62.1, 49.9.
1ꢀ(4ꢀmethoxybenzyl)ꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3h):39c
20 White solid; Mp = 128ꢀ130 °C; Rf = 0.45 (30 % Ethylacetate: nꢀ
1
hexane); H NMR (400 MHz, CDCl3): δH 7.78 (d, J = 7.2 Hz,
2H), 7.62 (s, 1H), 7.39 (t, J = 7.6 Hz, 2H), 7.32ꢀ7.25 (m, 3H),
6.90 (d, J = 8.8, 2H), 5.49 (s, 2H), 3.80 (s, 3H); 13C NMR (100
MHz, CDCl3): δc 159.9, 148.1, 130.6, 129.7, 128.8, 128.1, 126.7,
25 125.7, 119.3, 114.5, 55.4, 53.8.
4ꢀ(3ꢀphenyl)ꢀ1ꢀ(pꢀtolyl)propꢀ2ꢀynꢀ1ꢀyl)morpholine
(7b):40c
1
85 Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.32ꢀ7.30 (m,
4H), 7.23ꢀ7.21 (m, 3H), 7.17 (d, J = 8.0 Hz, 2H), 4.74 (s, 1H),
3.74ꢀ3.72 (m, 4H), 2.63ꢀ2.61 (m, 4H), 2.35 (s, 3H); 13C NMR
(100 MHz, CDCl3): δc 137.5, 134.9, 131.8, 128.9, 128.6, 128.3,
128.2, 123.1, 88.3, 85.4, 67.2, 61.8, 49.9, 21.2.
1ꢀ(4ꢀchlorobenzyl)ꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3i):39d White
solid; Mp = 132ꢀ134 °C; Rf = 0.5 (30 % Ethylacetate: nꢀhexane);
1H NMR (400 MHz, CDCl3): δH 7.80 (d, J = 7.2 Hz, 2H), 7.67 (s,
1H), 7.42ꢀ7.30 (m, 5H), 7.24 (d, J = 8.4 Hz, 2H), 5.54 (s, 2H);
30 13C NMR (100 MHz, CDCl3): δc 134.9, 133.2, 130.5, 129.5,
129.4, 129.0, 128.9, 128.3, 125.7, 119.5, 53.5.
90 4ꢀ(1ꢀ(4ꢀmethoxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)morpholine
1
(7c):40d Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.51ꢀ
1ꢀbenzylꢀ4,5ꢀdiphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3j):39e White solid;
Mp = 82ꢀ86 °C; Rf = 0.5 (30 % Ethylacetate: nꢀhexane); 1H NMR
(400 MHz, CDCl3): δH 7.55 (d, J = 6.8 Hz, 2H), 7.46 (d, J = 6.8
35 Hz, 1H), 7.41 (t, J = 7.6 Hz, 2H), 7.25ꢀ7.22 (m, 6H), 7.14 (d, J =
7.2 Hz, 2H), 7.03ꢀ7.01 (m, 2H), 5.40 (s, 2H); 13C NMR (100
MHz, CDCl3): δc 144.6, 139.4, 135.5, 133.9, 131.0, 130.2, 129.8,
129.3, 128.8, 128.5, 128.2, 127.9, 127.6, 126.8, 52.1.
7.49 (m, 4H), 7.33ꢀ7.31(m, 3H), 6.91ꢀ6.89 (m, 2H), 4.73(s, 1H)
3.81 (s, 3H), 3.74ꢀ3.71 (m, 4H), 2.63ꢀ2.59 (m, 4H); 13C NMR
(100 MHz, CDCl3): δc 171.1, 159.2, 131.8, 129.9, 129.7, 128.3,
95 123.0, 113.6, 88.3, 85.4, 67.2, 61.5, 55.3, 49.8.
4ꢀ(1ꢀ(4ꢀbromophenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)morpholine
1
(7d):40e Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.53ꢀ
4ꢀphenylꢀ1ꢀ(thiophenꢀ2ꢀylmethyl)ꢀ1Hꢀ1, 2, 3ꢀtriazole (3k):39f
7.47 (m, 6H), 7.34ꢀ7.32 (m, 3H), 4.74 (s, 1H), 3.76ꢀ3.68 (m. 4H),
2.62ꢀ2.59 (m, 4H); 13C NMR (100 MHz, CDCl3): δc 137.0,
100 131.8, 131.4, 130.3, 128.5, 128.4, 122.7, 121.8, 88.9, 84.3, 67.1,
61.5, 49.8.
40 White solid; Mp = 104ꢀ106 °C; Rf = 0.38 (20 % Ethylacetate: nꢀ
hexane); H NMR (400 MHZ, CDCl3): δH 7.71 (d, J = 7.2 Hz,
1
2H), 7.64 (s, 1H), 7.33ꢀ7.29 (m, 2H), 7.25ꢀ7.22 (m, 2H), 7.05ꢀ
7.04 (m, 1H), 6.93ꢀ6.91(m, 1H), 5.64 (s, 2H); 13C NMR (100
MHz, CDCl3): δc 147.2, 135.1, 129.5, 127.8, 127.2, 127.1, 126.3,
45 126.1, 124.7, 118.2, 47.5.
4ꢀ(1ꢀ(4ꢀchlorophenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)morpholine
(7e):40e Viscous liquid; 1H NMR (400 MHZ, CDCl3): δH 7.50 (d,
J = 8.4 Hz, 2H), 7.44ꢀ7.41 (m, 2H), 7.26ꢀ7.24 (m, 5H), 4.67(s,
105 1H) 3.66ꢀ3.64 (m, 4H), 2.54ꢀ2.51 (m, 4H); 13C NMR (100 MHz,
CDCl3): δc 136.5, 133.6, 131.8, 129.9, 128.4, 128.4, 122.7, 88.9,
84.4, 67.1, 61.4, 49.8.
1ꢀoctylꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3l):39g White solid; Mp =
1
62ꢀ64 °C; Rf = 0.5 (20 % Ethylacetate: nꢀhexane); H NMR (400
MHZ, CDCl3): δH 7.75 (d, J = 7.6 Hz, 2H), 7.67 (s, 1H), 7.34 (t, J
= 7.2 Hz, 2H), 7.26ꢀ7.22 (m, 1H), 4.29 (t, J = 7.6 Hz, 2H), 1.86ꢀ
50 1.83 (m, 2H), 1.26ꢀ1.18 (m, 10H), 0.79 (t, J = 7.2 Hz, 3H); 13C
NMR (100 MHz, CDCl3): δc 147.7, 130.8, 128.8, 128.1, 125.7,
119.4, 50.4, 31.7, 30.4, 29.1, 28.9, 26.5, 22.6, 14.1.
1ꢀ(3ꢀphenylꢀ1ꢀ(pꢀtolyl)propꢀ2ꢀynꢀ1ꢀyl)piperidine
(7g):40f
1
Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.51ꢀ7.49 (m,
110 4H), 7.31ꢀ7.30 (m, 3H), 7.17ꢀ7.15 (m, 2H), 4.75 (s, 1H), 2.60ꢀ
2.52 (m, 4H), 2.35 (s, 3H) 1.62ꢀ1.53 (m, 4H), 1.44ꢀ1.42 (m, 2H);
13C NMR (100 MHz, CDCl3): δc 137.1, 135.6, 131.8, 128.8,
128.5, 128.3, 128.0, 123.5, 87.6, 86.4, 62.2, 50.7, 26.2, 24.5,
21.2.
1ꢀhexylꢀ4ꢀphenylꢀ1Hꢀ1, 2, 3ꢀtriazole (3m):39f White solid; Mp =
72ꢀ74 °C; Rf = 0.55 (20 % Ethylacetate: nꢀhexane); 1H NMR (400
55 MHZ, CDCl3): δH 7.75 (d, J = 6.8 Hz, 2H), 7.67 (s, 1H), 7.34 (t, J
= 7.6 Hz, 2H), 7.26ꢀ7.22 (m, 1H), 4.30 (t, J = 7.2 Hz, 2H), 1.89ꢀ
1.82 (m, 2H), 1.29ꢀ1.21 (m, 6H), 0.81 (t, J = 7.2 Hz, 3H); 13C
NMR (100 MHz, CDCl3): δc 146.7, 129.7, 127.8, 127.0, 124.7,
118.3, 49.4, 30.1, 29.3, 25.1, 21.4, 12.9.
115 1ꢀ(1ꢀ(4ꢀmethoxyphenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)piperidine
1
(7h):40g Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.54ꢀ
7.49 (m, 4H), 7.32ꢀ7.30 (m, 3H), 6.88 (d, J = 7.6 Hz, 2H), 4.78 (s,
1H), 3.80 (s, 3H), 2.59ꢀ2.57 (m, 4H), 1.65ꢀ1.54 (m, 4H), 1.44ꢀ
1.42 (m, 2H); 13C NMR (100 MHz, CDCl3): δc 159.1 132.0,
120 131.8, 129.8, 128.3, 128.1, 114.3, 113.4, 87.7, 86.2, 61.7, 55.3,
50.5, 26.0, 24.4.
60 Ethylꢀ1ꢀbenzylꢀ1Hꢀ1,2,3ꢀtriazoleꢀ4ꢀcarboxylate (3n):39g White
solid; Mp = 82ꢀ86 °C; Rf = 0.15 (20 % Ethylacetate: nꢀhexane);
1H NMR (400 MHZ, CDCl3): δH 8.05 (s, 1H), 7.26ꢀ7.19 (m, 5H),
5.83 (s, 2H), 4.26 (q, J = 7.2 Hz, 2H), 1.26 (t, J = 7.2 Hz, 3H);
1ꢀ(1ꢀ(4ꢀbromophenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)piperidine
8
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 9 of 10
RSC Advances
View Article Online
DOI: 10.1039/C5RA05468K
1
(7i):40h Viscous liquid; H NMR (400 MHZ, CDCl3): δH 7.53ꢀ
7.48 (m, 6H), 7.45ꢀ7.32 (m, 3H), 4.73 (s, 1H), 2.54ꢀ2.51 (m, 4H),
1ꢀ62ꢀ1.57 (m, 4H), 1.45ꢀ1.44 (m, 2H); 13C NMR (100 MHz,
CDCl3): δc 137.9, 132.5, 131.9, 131.2, 130.2, 128.5, 123.1, 121.4,
88.3, 85.3, 61.8, 50.7, 26.2, 24.4.
65
J. Org. Chem. 1989, 54, 5302ꢀ5308; (d) W. Peng and S. Zhu,
Synlett. 2003, 187ꢀ190.
13. (a) K. Wang, X. Bi, S. Xing, P. Liao, Z. Fang, X. Meng, Q.
Zhang, Q. Liu and Y. Ji, Green Chem. 2011, 13, 562ꢀ565; (b)
T. Shamim and S. Paul, Catal. Lett. 2010, 136, 260ꢀ265.
14. V. V. Rostovtsev, L. G. Green, V. V. Fokin and K. B.
Sharpless, Angew. Chem. Int. Ed. 2002, 41, 2596ꢀ2599.
15. C. W. Tornoe, C. Christensen and M. Meldal, J. Org. Chem.
2002, 67, 3057ꢀ3064.
16. (a) V. D. Bock, H. Hiemstra and J. H. van Maarseveen, Eur.
J. Org. Chem. 2006, 51–68; (b) M. Medal and C. W. Tornoe,
Chem. Rev. 2008, 108, 2952–3015; (c) F. Amblard, J. H. Cho
and R. F. Schinazi, Chem. Rev. 2009, 109, 4207–4220; (d) J.
E. Hein and V. V. Fokin, Chem. Soc. Rev. 2010, 39, 1302–
1315; (e) L. Liang and D. Astruc, Coord. Chem. Rev. 2011,
255, 2933–2945; (f) S. DıezꢀGonzalez, Catal. Sci. Technol.
2011, 1, 166–178; (g) T. Jin, M. Yan and Y. Yamamoto,
Chem. Cat. Chem., 2012, 4, 1217–1229.
5
70
75
1ꢀ(1ꢀ(4ꢀchlorophenyl)ꢀ3ꢀphenylpropꢀ2ꢀynꢀ1ꢀyl)piperidine
(7j):40i Viscous liquid; 1H NMR (400 MHZ, CDCl3): δH 7.51 (d, J
= 7.6 Hz, 2H), 7.44ꢀ7.42 (m, 2H), 7.26ꢀ7.23 (m, 5H), 4.69 (s,
1H), 2.49ꢀ2.43 (m, 4H), 1.55ꢀ1.49 (m, 4H), 1.38ꢀ1.34 (m, 2H);
10 13C NMR (100 MHz, CDCl3): δc 137.4, 133.3, 131.9, 129.9,
128.7, 128.3, 123.2, 121.6, 88.4, 85.5, 61.9, 50.8, 26.3, 24.5.
Acknowledgements
80
Authors are grateful to the DSTꢀSERB (Project No. SB/FT/CSꢀ
033/2013) for the financial support and author R.S thanks to B S
15 Abdur Rahman University for her fellowship.
17. Q. Wang, S. Chittaboina, H. N. Barnhill, Lett. Org. Chem.
2005, 2, 293ꢀ301.
18. F. Himo, T. Lovell, R. Hilgraf, V. V. Rostovtsev, L.
Noodleman, K. B. Sharpless and V. V. Fokin, J. Am. Chem.
Soc. 2005, 127, 210ꢀ216.
85
References
19. S. Quader, S. E. Boyd, I. D. Jenkins and T. A. Houston, J.
Org. Chem. 2007, 72, 1962ꢀ1979.
20. (a) T. Jin, M. Yan, Menggernbateer, T. Minato, M. Bao and Y.
Yamamoto, Adv. Synth. Catal. 2011, 353, 3095–3100; (b) T.
L. Cook, J. A. Walker and J. Mack, Green Chem., 2013, 15,
617–619.
21. (a) J. Y. Kim, J. C. Park, H. Kang, H. Song and K. H. Park,
Chem. Commun., 2010, 46, 439–441; (b) C. Shao, R. Zhu, S.
Luo, Q. Zhang, X. Wang and Y. Hu, Tetrahedron Lett. 2011,
52, 3782–3785; (c) F. Alonso, Y. Moglie, G. Radivoy and M.
Yus, Synlett., 2012, 23, 2179–2182; (d) B. S. P. Anil Kumar,
K. Harsha Vardhan Reddy, G. Satish, R. Uday Kumar and Y.
V. D. Nageswar, RSC Adv., 2014, 4, 60652ꢀ60657.
1. H. C. Kolb, M. G. Finn and K. B. Sharpless, Angew. Chem.
Int. Ed., 2001, 40, 2004.
2. (a) R. A. Sheldon, I. Arends and U. Hanefeld, Green
90
20
25
30
35
40
45
50
55
60
Chemistry and Catalysis, WileyꢀVCH, Weinheim, 2007; (b) R.
A. Sheldon, Chem. Commun., 2008, 29, 3352–3365; (c) P.
Anastas and N. Eghbali, Chem. Soc. Rev., 2010, 39, 301.
3. S. Tan, X. Li, Y. Guo and Z. Zhang, Nanoscale., 2013, 5, 860.
4. K. T. Yong, I. Roy, M. T. Swihart and P. N. Prasad, J. Mater.
Chem., 2009, 19, 4655.
5. (a) P. Song, D. Wen, Z. X. Guo and T. Korakianitis, Phys.
Chem. Chem. Phys., 2008, 10, 5057; (b) H. Y. Shi, B. Deng, S.
L. Zhong, L. Wang and A. W. Xu, J. Mater. Chem., 2011, 21,
12309.
95
100
105
110
115
120
125
130
22. (a) B. H. Lipshutz and B. R. Taft, Angew. Chem., Int. Ed.
2006, 45, 8235–8238; (b) C.ꢀT. Lee, S. Huang and B. H.
Lipshutz, Adv. Synth. Catal. 2009, 351, 3139–3142; (c) M.
Fuchs, W. Goessler, C. Pilger and C. O. Kappe, Adv. Synth.
Catal. 2010, 352, 323–328; (d) F. Alonso, Y. Moglie, G.
Radivoy and M. Yus, Adv. Synth. Catal. 2010, 352, 3208–
3214; (e) F. Alonso, Y. Moglie, G. Radivoy and M. Yus, Org.
Biomol. Chem. 2011, 9, 6385–6395; (f) F. Alonso, Y. Moglie,
G. Radivoy and M. Yus, J. Org. Chem. 2011, 76, 8394–8405.
23. (a) Y. Wang, J. Liu and C. Xia, Adv. Synth. Catal. 2011, 353,
1534–1542; (b) M. Liu and O. Reiser, Org. Lett. 2011, 13,
1102–1105; (c) B. Kaboudin, Y. Abedi and T. Yokomatsu,
Org. Biomol. Chem. 2012, 10, 4543–4548; (d) A. Kumar, S.
Aerry, A. Saxena, A. de and S. Mozumdar, Green Chem.
2012, 14, 1298–1301; (e) Y. M. A. Yamada, S. M. Sarkar and
Y. Ouzumi, J. Am. Chem. Soc. 2012, 134, 9285–9290; (f) M.
Tajbakhsh, M. Farhang, S. M. Baghbanian, R. Hosseinzadeh
and M. Tajbakhsh, New. J. Chem., 2015, 39, 1827ꢀ1839.
24. (a) K. Namitharan, M. Kumarraja and K. Pitchumani, Chem.–
Eur. J. 2009, 15, 2755–2758; (b) J. C. Park, A. Y. Kim, J. Y.
Kim, S. Park, K. H. Park and H. Song, Chem. Commun. 2012,
48, 8484–8486; (c) M. N. S. Rad, S. Behrouz, M. M.
Doroodmand and A. Movahediyan, Tetrahedron, 2012, 68,
7812–7821; (d) S. Mohammed, A. K. Padala, B. A. Dar, B.
Singh, B. Sreedhar, R. A. Vishwakarma and S. B. Bharate,
Tetrahedron, 2012, 68, 8156–8162; (e) L. Wan and C. Cai,
Catal. Lett., 2012, 142, 1134–1140; (f) J.ꢀM. Collinson, J. D.
E. T. WiltonꢀEly and S. DıezꢀGonzalez, Chem. Commun.
2013, 49, 11358–11360; (g) B. A. Dar, A. Bhowmik, A.
Sharma, P. R. Sharma, A. Lazar, A.P. Singh, M. Sharma, B.
Singh, Applied Clay Science, 2013; (h) Y. R. Girish, K. S. S.
Kumar, U. Muddegowda, N. K. Lokanath, K. S. Rangappa and
S. Shashikanth, RSC Adv., 2014, 4, 55800; (i) J. M. Perez, R.
Cano and D. J. Ramon, RSC Adv., 2014, 4, 23943; (j) V. B.
6. (a) Y. Ding, Y. Wang, L. Zhang, H. Zhang, C. M. Li and Y.
Lei, Nanoscale, 2011, 3, 1149; (b) O. A. Sadik, A. L. Zhou, S.
Kikandi, N. Du, Q. Wang and K. Varner, J. Environ. Monit.,
2009, 11, 1782; (c) X. D. Wang, O. S. Wolfbeis and J. R.
Meier, Chem. Soc. Rev., 2013, 42, 7834.
7. D. Jariwala, V. K. Sangwan, L. J. Lauhon, T. J. Marks and M.
C. Hersam, Chem. Soc. Rev., 2013, 42, 2824.
8. J. Liao, Z. Yang, H. Wu, D. Yan, J. Qiu, Z. Song Y. Yang, D.
Zhou, and Z. Yin, J. Mater. Chem. C, 2013, 1, 6541.
9. H. Kang, Y. Zhu, X. Yang, J. Shen, C. Chen and C. Li, New J.
Chem., 2010, 34, 2166.
10. (a) H. Wamhoff, Comprehensive Heterocyclic Chemistry 1; A.
R. Katritzky and C. W. Rees, Eds.; Pergamon: Oxford, 1984,
5, 669; (b) S. Velazquez, R. Alvarez, C. Perez, F. Gago, C. De,
J. Balzarini and M. Camaraza, J. Antivir. Chem. Chemother.
1998, 9, 481; (c) C. Im, S. N. Maiti, R. G. Micetich, M.
Daneshtalab, K. Atchison and O. A. Phillips, J. Antibiot. 1994,
47, 1030; (d) M. J. Genin, D. A. Allwine, D. J. Anderson, M.
R. Barbachyn, D. E. Emmert, S. A. Garmon, D. R. Graber, K.
C. Grega, J. B. Hester, D. K. Hutchinson, J. Morris, R. J.
Reischer, C.W. Ford, G. E. Zurenko, J. C. Hamel, R. D.
Schaadt, D. Stapert and B. H. Yagi, J. Med. Chem. 2000, 43,
953; (e) W. Q. Fan, A. R. Katritzky, Comprehensive
Heterocyclic Chemistry II; A. R. Katritzky, C. W. Rees and E.
F. V. Scriven, Eds.; Elsevier Science: Oxford, 1996, 4, 1–126.
11. (a) R. Huisgen, In 1,3-Dipolar Cycloaddition Chemistry; A.
Padwa, Ed.; John Wiley: New York, 1984, 1ꢀ176; (b) C.ꢀK.
Sha and A. K. Mohanakrishan, In Synthetic Applications of
1,3-Dipolar Cycloaddition Chemistry toward Heterocycles
and Natural Products; A. Padwa and W. H. Pearson, Eds.;
Wiley: New York, 2003, 623 ꢀ 680.
12. (a) F. Palacios, A. M. Ochoa de Retana, J. Pagalday and J. M.
Sanchez, Org. Prep. Proced. Int. 1995, 27, 603ꢀ612; (b) D. J.
Hlasta and J. H. Ackerman, J. Org. Chem. 1994, 59, 6184ꢀ
6189; (c) W. L. Mock, T. A. Irra, J. P. Wepsiec and M. Adhya,
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 9

RSC Advances
Page 10 of 10
View Article Online
DOI: 10.1039/C5RA05468K
Purohit, S. C. Karad, K. H. Patel and D. K. Raval, RSC Adv.,
2014, 4, 46002.
25. (a) EꢀS. Lee, H.ꢀS. Yeom, JꢀH. Hwang and S. Shin, Eur. J.
Org.Chem., 2007, 3503ꢀ3507; (b) B. Jiang and M. Xu, Angew.
Chem. Int. Ed., 2004, 43, 2543ꢀ2546.
26. (a) S. Samai, G. C. Nandi and M. S. Singh, Tetrahedron Lett.
2010, 51, 5555–5558; (b) A. Bisai and V. K. Singh, Org. Lett.,
2006, 8, 2405ꢀ2408; (c) T. Okamura, K. Asano and S.
Matsubara, Synlett, 2010, 3053ꢀ3056.
27. (a) Z. Li, C. Wei, L. Chen, R. S. Varmab and C.ꢀJ. Li,
Tetrahedron Lett. 2004, 45, 2443– 2446; S. B. Park and H.
Alper, Chem. Commun. 2005, 1315–1317; (c) P. R. Likhar, S.
Roy, M. Roy, M. S. Subhas, M. L. De and R. L. Kantam ,
Synlett, 2007, 2301–2303; (d) B. J ꢀBorah, S. JꢀBorah, L.
Saikia and D. K. Dutta, Catal. Sci.Technol., 2014, 4, 1047ꢀ
1054; (e) M. L. Kantam, J. Yadav, S. Laha and S. Jha, Synlett,
2009, 40 1791–1794; (f) F. Nador, M. A. Volpe, F. Alonso, A.
Feldhoff, A. Kirschning and G. Radivo, Appl. Catal., A, 2013,
455, 39ꢀ45; (g) N. Anand, P. Ramudu, K. H. P. Reddy, K. S.
R. Rao, B. Jagadeesh, V. S. P. Babu and D. R. Burri, Appl.
Catal., A, 2013, 45 454, 119ꢀ126; (f) X. Zhang and A. Corma,
Angew. Chem. Int. Ed., 2008, 47, 4358ꢀ4361.
28. (a) R. Cella and H. A. Stefani, Tetrahedron, 2009, 65, 2619;
(b) G. Cravotto and P. Cintas, Chem. Soc. Rev, 2006, 35, 180;
(c) B. Dar, M. Sharma and B. Singh, Bull. of Chem. React.
Eng. & Catal., 2012, 7, 79; (d) M. Driowya, A. Puissant, G.
Robert, P. Auberger, R. Benhida, K. Bougrin, Ultrason.
Sonochem. 2012, 19, 1132; (e) T. J. Mason, Chem. Soc. Rev.
1997, 26, 443.
38. J. E. Hein and V. V. Fokin, Chem. Soc. Rev. 2010, 39, 1302.
39. (a) K. Kamata, Y. Nakagawa, K. Yamaguchi and N. Mizuno,
J. Am. Chem. Soc., 2008, 130, 15304; (b) P. Appukkuttan, W.
Dehaen, V. V. Fokin and E. V. Eycken, Org. Lett., 2004, 6,
4223; (c) C.ꢀZ. Tao, X. Cui, A.ꢀX. Liu, L. Liu and Q.ꢀX. Guo,
Tetrahedron Lett. 2007, 48, 3525ꢀ3529; (d) C. S. Radatz, L. D.
A. Soares, E. R. Vieira, D. Alves, D. Russowsky and P. H.
Schneider, New. J. Chem. 2014, 38, 1410ꢀ1417; (e) L. Zhang,
.X. Chen, P. Xue, H. H. Y. Sun, I. D. Williams, K. B.
Sharpless, V. V. Fokin and G. Jia, J. Am. Chem. Soc. 2005,
127, 15998; (f) Z. Chen, Q. Yan, H.Yi, Z. Liu, A. Lei, and Y.
Zhang, Chem. Eur. J. 2014, 20, 13692–13697; (g) J. H. Kim
and S. Kim, RSC Adv., 2014, 4, 26516ꢀ26523.
40. (a) L. L. Chang, J. Yang, Y. Wei and J. Y. Ying, Adv. Synth.
Catal. 2009, 351, 2887–2896; (b) K.M. Reddy, N.S. Babu, I.
Suryanarayana, P.S.S. Prasad and N. Lingaiah, Tetrahedron
Lett. 2006, 47, 7563–7566; (c) P. Li and L. Wang,
Tetrahedron. 2007, 63, 5455–5459; (d) K. Namitharan and K.
Pitchumani, Eur. J. Org. Chem. 2010, 411–415; (e) J. Lim, K.
Park, A. Byeun, and S. Lee, Tetrahedron Lett. 2014, 55, 4875–
4878; (f) N. P. Eagalapatia, A. Rajacka and Y.L.N. Murthy. J.
Mol. Catal. A: Chem. 2014, 381,126– 131; (g) S. Samai, G.C.
Nandi and M.S. Singh, Tetrahedron Lett. 2010, 51, 5555–
5558; (h) K.V.V. Satyanarayana, P. Atchuta Ramaiah, Y.L.N.
Murty, M. Ravi Chandra and S.V.N. Pammi, Catal. Commun.
2012, 25, 50–53; (i) C. Wei and C. J. Li, J. Am. Chem. Soc.
2003, 125, 9584–9585.
70
75
80
85
90
95
5
10
15
20
25
30
35
40
41. (a) S. N. Shkerin, M. V. Kuznetsov and N. A. Kalashnikova,
Russ. J. Electrochem. 2003, 39, 591−599; (b) M. M. Natile, A.
Ponzoni, I. Concina and Antonella Glisenti, Chem. Mater.
2014, 26, 1505−1513.
29. L. Q. Ding, W. Wang and A.Q. Zhang, Ultrason. Sonochem,
2007, 14, 563.
30. J. K. Kim, F. Martinez and I. S. Metcalfe, Catal. Today, 2007,
124, 224.
31. (a) P. Cintas, A. Barge, S. Tagliapietra, L. Boffa and G.
Cravotto, Nat. Protoc., 2010, 5,607; (b) G. Cravotto, V.V.
Fokin, D. Garella, A. Binello, L. Boffa and A. J. Barge, J.
Comb. Chem. 2010, 12, 13.
32. (a) R. Srivastava, M. U. A. Prathap and R. Kore, Colloids Surf.
A: Physicochem. Eng. Aspects. 2011, 392, 271–282; (b) A. S.
Ethiraj and D. J. Kang, Nanoscale Res. Lett.. 2012, 7, 70.
33. A. S. Priya, I. B. S. Banu and M. Chavali, Arab. J. Sci. Eng.,
2015, (In press) (DOI 10.1007/s13369ꢀ015ꢀ1668ꢀz).
34. (a) J. Moulder, W. Sticke, P. Sobol and K. Bomben, Standard
ESCA spectra of the elements and line energy information. In
Handbook of X-ray Photoelectron Spectroscopy, Edited by: J.
Chastain, USA, Perkin Elmer Coorporation, Physical
Electronics Division; 1992; (b) Z. S. Hong, Y. Cao, J. F. Deng,
Mater. Lett., 2002, 52, 34ꢀ38; (c) C. Xu, Y. Lin, G. Xu and G.
Wang G Mater. Res. Bull. 2002, 37, 2365ꢀ2372; (d) R. A.
Zarate, F. Hevia, S. Fuentes, V. M. Fuenzalida, A. Zuniga, J.
Solid State Chem., 2007, 180, 1464ꢀ1469; (e) D. Mrabet, A.
Abassi, R. Cherizol, T.ꢀO. Do, Appl. Cata. A-Gen., 2012, 447–
448, 60–66; (f) M. Pashchanka, R. C. Hoffmann, A. Gurlo, J.
C. Swarbrick, J. Khanderi, J. Engstler, A. Issanind and J. J.
Schneider, Dalton Trans., 2011, 40, 4307–4314.
45
50
55
60
65
35. (a) J. Ghijsen, L. H. Tjeng, J. V. Elp, H. Eskes, J. Westerink,
G. A. Sawatzky and M. T. Czyzyk, Phys. ReV. B, 1988, 38,
11322; (b) C.ꢀK. Wu, M. Yin, S. O’Brien and J. T. Koberstein,
Chem. Mater. 2006, 18, 6054ꢀ6058.
36. (a) S. Poulston, P. M. Parlett, P. Stone and M. Bowker, Surf.
Interface Anal., 1996, 24, 811–820; (b) A. T. GarciaꢀEsparza,
K. Limkrailassiri, F. Leroy, S. Rasul, W. Yu, L. Lin and K.
Takanabe, J. Mater. Chem. A, 2014, 2, 7389–7401.
37. (a) X. Ma, H. Zhang, Y. Ji, J. Xu and D. Yang, Mater. Lett.
2004, 58, 1180–1182; (b) M. Zhou, J. Yuan, W. Yuan, Y. Yin
and X. Hong, Nanotechnology, 2007, 18, 405704–405710; (c)
M. SalavatiꢀNiasari, G. Hosseinzadeha, F. Davar, J. Alloy.
Compd., 2011, 509, 4098–4103.
10 | Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]