Magnetically recyclable sepiolite/iron oxide/cupric oxide nanocomposite as a novel catalyst for the synthesis of S-aryl dithiocarbamates by C-S bond formation

Article abstract of DOI:10.1002/jccs.202100049

A convenient and efficient procedure is described for the synthesis of S-aryl dithiocarbamates by C-S bond formation through the coupling reaction of three components between secondary amines, carbon disulfide, and aryl iodides using magnetically separabl

Full text of DOI:10.1002/jccs.202100049

Received: 4 February 2021
DOI: 10.1002/jccs.202100049
Revised: 10 June 2021
Accepted: 22 June 2021
A R T I C L E
Magnetically recyclable sepiolite/iron oxide/cupric oxide
nanocomposite as a novel catalyst for the synthesis of S-aryl
dithiocarbamates by C S bond formation
Fatemeh Hassani Bagheri1 | Hojatollah Khabazzadeh1 | Maryam Fayazi2
1Department of Chemistry, Shahid
Abstract
Bahonar University of Kerman,
Kerman, Iran
A convenient and efficient procedure is described for the synthesis of S-aryl
dithiocarbamates by C S bond formation through the coupling reaction of
three components between secondary amines, carbon disulfide, and aryl
iodides using magnetically separable and reusable sepiolite/iron oxide/cupric
oxide (SEP/Fe3O4/CuO) nanocomposite as a heterogeneous catalyst. The
results show that (SEP/Fe3O4/CuO) nanocomposite has good activity, and
could be easily separated from the reaction mixture using an external magnet.
The high efficiency of the nanocomposite was related to the temperature of
100ꢀС and dimethylformamide (DMF) as a solvent. The structure, morphology,
and crystalline phases of the prepared (SEP/Fe3O4/CuO) nanocomposite were
characterized by Fourier transform infrared spectroscopy (FT-IR), vibrating-
sample magnetometer (VSM), scanning electron microscopy (SEM), induc-
tively coupled plasma (ICP), and X-ray powder diffraction (XRD).
2Department of Environment, Institute of
Science and High Technology and
Environmental Sciences, Graduate
University of Advanced Technology,
Kerman, Iran
Correspondence
Fatemeh Hassani Bagheri, Department of
Chemistry, Shahid Bahonar University of
Kerman, 7616914111, Kerman, Iran.
Email: hkhabazzadeh@uk.ac.ir
K E Y W O R D S
carbon disulfide, cupric oxide, heterogeneous catalyst, S-aryl dithiocarbamates, sepiolite
1 | INTRODUCTION
The bond formation between carbon and sulfur is rela-
tively problematic due to the parallel oxidative S S bond
Carbon-heteroatom cross-coupling reactions play a vital
role in synthesizing organic compounds[1,2] and they are
a crucial step in designing the synthesis of industrially
and biologically active materials. These reactions were
used in synthesizing therapeutic medicines for diabetes,
inflammation, HIV, and cancer.[3–5] Methods used for the
C S bond-forming are vital tools in synthetic chemistry
because of the frequent occurrence of these structural
units in biologically active molecules.[6–7] Their impor-
tance is due to the broad utilizations of organo-sulfur
compounds in diverse sciences.[8] So, the formation of
carbon–sulfur bonds is an essential part in the prepara-
tion of numerous biological, pharmaceutical, and chemi-
cal molecules.[9] Forming a C S bond is a fundamental
approach to introduce sulfur into organic compounds.
creation and consequently deactivation of metal-based
catalysts by sulfur-containing compounds. A wide range
of transition metals, including Cu,[10–11] Pd,[12] Ni,[13]
Co,[14] and Fe[15] catalysts, with suitable ligands, are all
well explored for C S bond-forming.
S-aryl dithiocarbamates, due to their interesting chemistry
and wide range of utilities, are vital structural forms occurring
in numerous natural products,[16] agrochemicals and pharma-
ceuticals.[17] They have many potential applications, for exam-
ple, as linkers in solid phase organic synthesis,[18]
agrochemicals,[19] as versatile synthetic intermediates,[20] bio-
logically active compounds,[16] protecting groups in peptide
synthesis,[21] and in the synthesis of ionic liquids.[22] The most
common method in synthesizing the dithiocarbamates is the
reaction of amines with isothiocyanates or thiophosgene,[23]
J Chin Chem Soc. 2021;1–12.
http://www.jccs.wiley-vch.de
© 2021 The Chemical Society Located in Taipei & Wiley-VCH GmbH
1

2
BAGHERI ET AL.
which are not environmentally acceptable.[24] Most of the pro-
tocols, however, suffer from drawbacks such as harsh reaction
conditions, high temperature, prolonged reaction time, use of
homogeneous catalyst, and rapid loss of catalytic activity.
Although the acceptable yield for the synthesis of dithiocarba-
mates has been reported in most protocols, the improvement
of protocols for the synthesis of these compounds, which are
cheap, practical, and environmentally benign, is highly
desirable. Therefore, developing low-cost, practical, and envi-
ronmentally benign protocols for the synthesis of dithiocarba-
mates is highly desirable. The present paper reports a one-pot
multicomponent condensation of amines, carbon disulfide,
and aryl halides for the synthesis of S-aryl dithiocarbamates
by C S bond formation with a magnetically recyclable
sepiolite/iron oxide/cupric oxide (SEP/Fe3O4/CuO) nano-
composite (Scheme 1).
Basically, the catalyst is considered as a chemical
compound able to exert a directing and accelerating effect
on the progress of a reaction that is thermodynamically
possible. When the phase catalyst forms a separate phase
from the reaction phase, it is called a “heterogeneous cat-
alyst”, and in the case of a catalyst soluble in the reaction
medium, it is referred to as a “homogeneous catalyst”.[25]
Therefore, development of methods that lead to the prep-
aration of heterogeneous catalysts in a simple and green
environment remains an active area of research.
Heterogeneous catalysts are cheaper and have always
been one of the most important goals for chemists in
industrial development. Recently, various clay materials
as efficient catalytic substrate have been utilized for
organic synthesis because of their unique features such
as numerous abundance, low cost, and good physico-
chemical properties.[26–28] Of interest is SEP being a
hydrated magnesium silicate clay mineral with a large
specific surface area, appropriate mechanical resistance,
and fibrous morphology.[29] Despite these advantages, its
difficult separation from the reaction mixture limits the
application of SEP as a catalyst substrate in organic trans-
formations.[30] The modification of SEP fibers with the
iron oxide component seems to be a proper way to over-
come this limitation. The magnetic property enables easy
catalyst recovery from the organic reactions by applying
an external magnetic field. Therefore, we designed an
efficient, stable, inexpensive, and heterogeneous copper
catalyst that performs carbon–sulfur bond formation
reactions for the synthesis of S-aryl carbamodithioate
compounds.
2 | RESULTS AND DISCUSSION
The SEP/Fe3O4/CuO catalyst employed for C S coupling
was synthesized according to the literature procedure.
We developed a recyclable inexpensive catalyst for the
synthesis of S-aryl dithiocarbamates. The resulted
nanocatalyst was characterized using various characteri-
zation techniques such as FT-IR, XRD, FE-SEM, EDX,
VSM, and ICP.
The FT-IR spectrum of SEP (a), SEP/Fe3O4 (b), and
SEP/Fe3O4/CuO (c) is depicted in Figure 1. In spectrum
(a), the stretching vibration at 1,657 cmÀ1 can be attrib-
uted to the water of zeolite, 1,215 cmÀ1 to the Si O
bands vibration, and the bands at 1,013 and 470 cmÀ1
can be assigned as Si O Si vibration.[31] The absorption
bands at 3,686 and 3,555 cmÀ1 correspond to the OH
groups of Mg OH. Figure 1 (b) shows the FT-IR spec-
trum of SEP/Fe3O4. The typical bands that appear at
437–647 cmÀ1 are caused by the Fe O stretching vibra-
tion, and the band located at around 1,012 cmÀ1 is due to
the Si O Fe linkage. The absorption band at
3,554 cmÀ1 shows the stretching vibrations of the
hydroxyl groups in Fe3O4 and water.[32] The FT-IR
spectrum of the final catalyst (SEP/Fe3O4/CuO) is indicated in
Figure 1c. In comparison, the SEP/Fe3O4/CuO has a new
absorption band than SEP/Fe3O4. The band observed at
1,369 cmÀ1 is assigned to the bending vibration of Cu O bond.
Figure 2 shows the XRD profiles of the SEP, SEP/-
Fe3O4, and SEP/Fe3O4/CuO nanocomposites. For the
SEP sample, the diffraction peaks at 2θ = 19.9ꢀ, 20.8ꢀ,
23.9ꢀ, 26.9ꢀ, 28.2ꢀ, 35.1ꢀ, 36.9ꢀ, 39.8ꢀ, 43.7ꢀ, and 59.6ꢀ cor-
respond to the (060), (131), (260), (080), (331), (371),
(202), (541), (412), and (791) planes (JCPDS No. 13-0595),
respectively.[33] The XRD pattern of the SEP/Fe3O4
depicts some new peaks at 2θ values of 30.3ꢀ, 35.7ꢀ, 43.4ꢀ,
57.5ꢀ, and 63.1ꢀ, which can be assigned to (220), (311),
(400), (511), and (440) crystalline planes of magnetite
(JCPDS No. 19-0629), respectively.[34] In the case of the
SEP/Fe3O4/CuO sample, a new diffraction peak at 39.1ꢀ
(200) can be ascribed to the monoclinic CuO according to
JCPDS No. 02-1041.[35] The peaks at 2θ = 35.8ꢀ (002),
SCHEME 1 Synthesis of S-aryl
dithiocarbamates

BAGHERI ET AL.
3
spectrum of SEP/Fe3O4/CuO composite, the existence of
Fe and Cu element energy peaks confirms the successful
deposition of iron oxide and cupric oxide crystals on the
surface of SEP fibers.
In addition, the element distribution of SEP/Fe3O4/
CuO (Figure 5) indicates the uniform deposition of the
Fe3O4 and CuO nanoparticles on the SEP support.
The magnetic behavior of the as-prepared SEP/-
Fe3O4/CuO was studied to evaluate the possibility of
magnetic separation and recycling of this catalyst. The
magnetic hysteresis curves of the SEP/Fe3O4 and SEP/-
Fe3O4/CuO nanocomposites are displayed in Figure 6. As
shown, the magnetization saturation (Ms) values decrease
from 30.4 emu gÀ1 (SEP/Fe3O4) to 9.0 emu gÀ1
(SEP/Fe3O4/CuO), which could be attributed to the exis-
tence of nonmagnetic CuO material. However, the level
of magnetism of the SEP/Fe3O4/CuO catalyst is enough
to separate the catalyst using an external magnetic field.
On the basis of ICP-OES analysis, the weight percent-
age of Cu was obtained equal to 16.19%.
FIGURE 1 The FT-IR spectrum of sepiolite (a), SEP/Fe3O4 (b),
and SEP/Fe3O4/CuO (c)
After characterization, the catalyst activity was
checked in the C S cross-coupling reaction for the syn-
thesis of the S-aryl dithiocarbamates (Scheme 1). First,
the reactions of the secondary amine, aryl iodide, and
carbon disulfide under various conditions were investi-
gated to set up the optimal conditions. The results are
summarized in Table 1.
To optimize the reaction conditions, the mixture of
morpholine (1.2 mmol), 4-iodo anisole (1.0 mmol), CS2
(2.0 mmol), K2CO3 (1.2 mmol), and 20 mg catalyst in
2 ml of DMF under air atmosphere at 80ꢀC was selected
as a model reaction. This reaction was also carried out at
several temperatures, for which the highest efficiency
was obtained at 100ꢀC (Table 1, entries 2–3).
When the reaction solvent was reduced to 1 ml, the
reaction efficiency increased significantly (Table 1, entry 4).
The time to complete the reaction was checked by TLC, as
shown in Table 1 (entries 4, 5, 20, 21). The reaction
efficiency did not differ from 12 to 24 hr, so 12 hr was
selected as the best time. No products were obtained when
the mentioned reaction was performed in DMSO, Dioxane,
and EtOH as solvent (Table 1, entries 12–14). The reaction
efficiency also decreased when using water and DMF as sol-
vents (Table 1, entry 18). By increasing the catalyst amount
to 40 mg, there was a significant decrease in efficiency, so
20 mg of catalyst was selected (Table 1, entries 6–7). In
addition, some other different bases such as Et3N, Na2CO3,
and K3PO4 were examined. Best yields were obtained
when applying K2CO3 or Et3N were used as bases (Table 1,
entries 5 and 15). This reaction was also carried out with
different amounts of morpholine and carbon disulfide. As
can be seen in Table 1, the optimized amount of
morpholine was 1.2 mmol and CS2 2 mmol. Performing
FIGURE 2 XRD patterns of SEP, SEP/Fe3O4, and SEP/Fe3O4/
CuO nanocomposites
53.9ꢀ (202), and 58.3ꢀ (202) are also overlapped with the
diffraction peaks of SEP and Fe3O4 in the prepared
nanocomposite, which makes it difficult to identify the
crystal structure of CuO particles. In addition, the reduc-
tion in peak intensities is caused by the surface coverage
of the SEP/Fe3O4 sample by CuO particles.
The surface morphologies of different samples are
illustrated in Figure 3. As can be seen, the SEP presents a
needle-like morphology. In SEP/Fe3O4/CuO, larger quan-
tities of nanoparticles in spherical shape are dispersed on
the SEP support.
The catalyst surface presents some characteristic
peaks in the EDX spectrum (Figure 4), which confirms
the presence of Fe and Cu, along with other species,
including O, Mg, and Si elements. From the EDX

4
BAGHERI ET AL.
FIGURE 3 FE-SEM images of SEP/Fe3O4/CuO nanocomposite
variety of aryl halides and secondary amines were subjected
to optimal conditions, and the results are shown in Table 2.
Most products were known and characterized by melting
1
point (mp), IR, H NMR, and 13C NMR data as well as by
comparing their physical data with those in the literature.
Also, new products synthesized by elemental analysis
(CHNS) were approved.
The IR spectrum of compound 3a exhibited absorp-
tion bands in the area of 2,854 and 2,924 cmÀ1 for the
1
CH2 groups of morpholine ring. The H NMR spectrum
showed protons of the aromatic ring in the field of 7.01–
7.37 ppm. Protons of morpholine (CH2) appeared at
3.71–3.74 and 4.07–4.20 ppm. The OCH3 proton was
seen as a singlet at δ = 3.83 ppm. The 13C NMR spec-
trum of 3a exhibited eight signals that are consistent
with the proposed structure. The presence of a peak in
the area of 197.1 ppm indicates the presence of a
C═S bond.
FIGURE 4 EDX spectrum of SEP/Fe3O4/CuO nanocomposite
this reaction under N2 atmosphere showed no difference
compared with that under air atmosphere (Table 1, entries
5 and 19). No product was formed when performing the
reaction in the absence of a catalyst and during the use of
sepiolite (C1) and SEP/Fe3O4 (C2) as catalysts (Table 1,
entry 22–24). With the optimal conditions determined, a
The recyclability of the catalyst was checked during
the preparation of product 2a. After the reaction was
completed in the first run, an external magnet was used

BAGHERI ET AL.
5
FIGURE 5 SEM elemental mapping
(yellow stand for Cu, purple stand for O,
blue stand for Si, green stand for Fe, red
stand for Mg) for SEP/Fe3O4/CuO
nanocomposite
Scheme 2 shows the proposed mechanism for the
coupling reaction of three components between second-
ary amines, carbon disulfide, and aryl iodides. According
to the previously reported mechanisms, first, the reaction
of a carbondisulfide with secondary amine gives the
dithiocarbamate anion, and then the oxidation of catalyst
is taken place by an aryl iodide. Finally, the cross-
coupling reaction of aryl iodide and dithiocarbamate
anion followed by a reductive elimination yields the
corresponding S-aryl-carbamodithioate as the main prod-
ucts, and this expands the catalytic cycle.
To show the efficacy of the SEP/Fe3O4/CuO nano-
particles for the synthesis of S-aryl dithiocarbamates, the
results of this method were compared with some previously
reported catalysts for compounds 1a and 4a (Table 3).
3 | EXPERIMENTAL
FIGURE 6 VSM of SEP/Fe3O4/CuO nanocomposite
3.1 | Materials and methods
for the separation of the catalyst from the reaction mix-
ture. The recycled catalyst was washed twice with ethyl
acetate, dried at ambient temperature, and used for the
next run. The reaction was repeated for up to three con-
secutive runs, and the results of which are shown in
Figure 7.
Moreover, the XRD pattern (Figure 8) of the SEP/-
Fe3O4/CuO catalyst after catalytic test did not show any
significant variation in the crystal structure, implying the
excellent stability of the SEP/Fe3O4/CuO nanocomposite.
The FT-IR spectrum (Figure 9) of the nanocomposite
after three uses showed no changes. Also on the basis of
ICP-OES analysis, the percentage of copper weight
decreased from 16.19% to 15.83%.
The natural sepiolite used for the preparation of catalyst
was purchased from Dorkav Minig Company (Mashhad,
Iran). Before using in the experiments, the SEP sample
was purified according to the literature.[37] For SEP/-
Fe3O4/CuO preparation, analytical-grade of ferric
chloride hexahydrate (FeCl3Á6H2O), ferrous sulfate
heptahydrate (FeSO4Á7H2O), ammonia solution (25%),
copper acetate monohydrate (Cu[OAc]2ÁH2O), and
sodium hydroxide (NaOH) were purchased from Merck
(Darmstadt, Germany). All solvents and materials pur-
chased from Merck chemical company and solvents for
the reaction were distilled before use: DMF, 1, 4-dioxane,
DMSO, ethanol, n-hexane, and ethyl acetate. All the

6
BAGHERI ET AL.
TABLE 1 Optimization of reaction conditions for S-aryl dithiocarbamates
Catalyst
Entry amount (mg)
CS2 (Mol
Morpholin ratio)
T
(ꢀC)
Time
(h)
Yielda
Atmosphere (%)
Base
Solvent
1
C3b (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (40)
C3 (10)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
C3 (20)
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
2
2
2
2
2
2
2
2
3
1.5
2
2
2
2
2
2
2
2
2
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Et3N
DMF (2 cc)
DMF (2 cc)
DMF (2 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
Dioxane (1 cc)
DMSO (1 cc)
EtOH (1 cc)
DMF (1 cc)
80
24
24
24
24
12
12
12
12
12
12
12
12
12
12
12
12
12
12
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
Air
31
45
23
54
54c
45
38
15
8
2
100
120
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
15
54
0
1.5
1.2
1.2
1.2
1.2
1.2
1.2
1.2
0
0
54
31
38
46
Na2CO3 DMF (1 cc)
K3PO4
K2CO3
DMF (1 cc)
DMF: 0.8 cc
+ H2O:0.2 cc
19
20
21
22
23
24
C3 (20)
C3 (20)
C3 (20)
C1d (20)
C2e (20)
0
1.2
1.2
1.2
1.2
1.2
1.2
2
2
2
2
2
2
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
DMF (1 cc)
100
100
100
100
100
100
12
6
N2
54
23
38
0
Air
Air
Air
Air
Air
9
12
12
12
0
0
Note: Reaction conditions: mopholine (1.2 mmol), 4-Iodo anisole (1 mmol), catalyst, CS2 (2 mmol), base (1.2 mmol) in 1.0 ml of solvent for 12 hr. The blod
values are for highlighting optimized conditions.
aIsolated yield.
bC3: SEP/Fe3O4/CuO.
cOptimized conditions.
dC1: sepiolite.
eC2: SEP/Fe3O4.
reactions were performed in sealed tubes and monitored
by TLC. The products were purified by thin-layer chro-
matography (TLC) plates (silica gel G). IR spectra were
recorded on a BRUKER Tensor-27 FT-IR spectrophotom-
eter using KBr pellets, and all melting points were mea-
sured on an Electrothermal-9,100 apparatus. Proton
nuclear magnetic resonance spectra (1H NMR) and car-
bon nuclear magnetic resonance spectra (13C NMR) were
recorded on a Bruker 300 AVANCE III NMR magnet
1
(300 MHz for H NMR and 75 MHz for 13C NMR) using
DMSO-d6 as a solvent. Field emission scanning electron
microscopy (FE-SEM) studies were performed on a
SIGMA VP microscope (Zeiss, Germany) equipped with
an energy-dispersive X-ray (EDX) system. The X-ray
diffraction (XRD) analysis was carried out using an X'Pert
PRO powder diffractometer (PANalytical B.V.,

BAGHERI ET AL.
7
TABLE 2 Synthesis of S-aryl dithiocarbamates
Entry
Compounds
Secondary amine
Aryl iodide
Product
Yield (%)
1
1a
76
2
3
2a
3a
67
54
4
4a
77
5
6
7
5a
6a
7a
60
80
68
8
8a
65
9
9a
82
76
64
10
11
10a
11a
(Continues)

8
BAGHERI ET AL.
TABLE 2 (Continued)
Entry
Compounds
Secondary amine
Aryl iodide
Product
Yield (%)
12
12a
70
100
80
60
40
20
0
1
2
3
Run
FIGURE 7 Reusability of SEP/Fe3O4/CuO in the compound 2a
FIGURE 9 FT-IR of SEP/Fe3O4/CuO nanocomposite: a)
before; and b) after catalytic reaction
presence of the purified SEP. First, 4.0 g of SEP powder
was added to a beaker (300 ml) that contained 200 ml of
FeCl3Á6H2O (0.06 M) and FeSO4Á7H2O (0.03 M) solution.
The mixture was sonicated for 15 min under nitrogen
atmosphere at 40ꢀC. Then, 11 ml of aqueous ammonia
(25% w/w) was added dropwise into the mixture with vig-
orous stirring at 60ꢀC. Nitrogen stream was employed
during the reaction to prevent critical oxidation. After
aging for 2 hr at 60ꢀC, the prepared SEP/Fe3O4
nanocomposite was collected with a magnet and washed
with pure water several times. The product was dried at
60ꢀC in a vacuum drying oven overnight.
The SEP/Fe3O4/CuO nanocomposite was prepared
with a facile solvothermal procedure. Briefly, 3.0 g of the
SEP/Fe3O4 nanocomposite was dispersed into 110 ml
ethanolic solution of Cu(OAc)2ÁH2O (0.15 M) for 30 min.
In the next step, 1.0 g of NaOH pellets was added to the
mixture. After mixing for 5 min, the resulting mixed solu-
tion was poured into a Teflon-lined stainless steel auto-
clave (150 ml), sealed, and then heated at 130ꢀC for
24 hr. Finally, the black product was rinsed with absolute
ethanol and distilled water for several times, and then
dried at 60ꢀC overnight (Scheme 3).
FIGURE 8 XRD patterns of SEP/Fe3O4/CuO nanocomposite
before and after catalytic reaction
Netherlands) using Cu Kα radiation (λ = 0.154 nm). The
magnetic property of the samples was determined using a
vibrating-sample magnetometer (VSM) (Meghnatis
Daghigh Kavir Co., Iran) at room temperature. The resid-
ual copper concentration was quantified by an induc-
tively coupled plasma-optical emission spectrometer
(ICP-OES, 7900, AGILENT, USA).
3.2 | Catalyst preparation
The SEP/Fe3O4 nanocomposite was prepared by co-
precipitation of FeSO4Á7H2O and FeCl3Á6H2O, in the

BAGHERI ET AL.
9
SCHEME 2 Proposed mechanism
for the synthesis of S-aryl
dithiocarbamates
TABLE 3 Comparison of the reaction between secondary amines, carbon disulfide, and aryl iodides (compounds 1a and 4a) in the
presence of SEP/Fe3O4/CuO nanocomposite and some previously reported catalysts
Entry
Product
Catalyst
Time (hr)
Yield (%)
Ref.
36
20
-
1
1a
1a
1a
4a
4a
Cu(II) nanocatalyst supported on modified AlPO4
Fe3O4–CuO MNPs
17
10
12
12
12
82
80
76
65
77
2
3a
SEP/Fe3O4/CuO
4
5a
Fe3O4–CuO MNPs
20
SEP/Fe3O4/CuO
aPresent work.
3.3 | General procedure for the synthesis
of S-aryl dithiocarbamates (1–12a)
7.44–7.53 (m, 5H, arom). 13C NMR (75 MHz, DMSO-
d6) (ppm): 51.7, 66.1, 129.6, 130.5, 131.1,
δ
137.3, 195.9.
In a sealed tube with a magnetic stir-bar in room temper-
ature, CS2 (2 mmol), aryl iodide (1.0 mmol), K2CO3
(1.2 mmol), and SEP-Fe3O4-CuO (20 mg) were added to
secondary amine (1.2 mmol) in 1 ml of DMF. After
30 min, the reaction mixture was heated at 100ꢀC for
12 hr (checked by TLC). After accomplishment of the
reaction, the reaction mixture was extracted with ethyl
acetate and purified by thin-layer chromatography (TLC)
plates (silica gel) using n-hexane/ethyl acetate (4:2)
affording the desired products.
3.5 | P-Tolyl morpholine-
4-carbodithioate (2a)[39]
Yellow solid, mp 134–137ꢀC. IR (KBr): 1,175, 1,589,
2,852, 2,916, 2,972 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 2.38 (s, 3H,
CH3), 3.71–3.74 (m, 4H, 2CH2), 4.07–4.20 (broad, 4H, 2CH2),
7.29 (d, J = 8.3 Hz, 2H, arom), 7.33 (d, J = 8.5 Hz, 2H, arom).
13C NMR (75 MHz, DMSO-d6) δ (ppm): 21.4, 51.7, 66.1, 127.7,
130.3, 137.2, 140.4, 196.4.
3.4 | Phenyl morpholine-
4-carbodithioate (1a)[38]
3.6 | 4-Methoxyphenyl morpholine-
Light brown solid, mp 137–139ꢀC. IR (KBr): 1,188, 1,575,
4-carbodithioate (3a)[39]
2,849, 2,920 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 3.72–3.75
(m, 4H, 2CH2), 4.08–4.21 (broad, 4H, 2CH2),
Yellow solid, mp 133–135ꢀC. IR (KBr): 1,166, 1,588,
2,854, 2,924, 2,957 cmÀ1
.

10
BAGHERI ET AL.
SCHEME 3 Synthesis of SEP-Fe3O4-CuO
1H NMR (300 MHz, DMSO-d6) δ (ppm): 3.73 (t,
J = 4.9 Hz, 4H, 2CH2), 3.83 (s, 3H, OCH3), 4.07–4.20
(broad, 4H, 2CH2), 7.03 (d, J = 8.8 Hz, 2H, arom), 7.35
(d, J = 8.8 Hz, 2H, arom). 13C NMR (75 MHz, DMSO-
d6) δ (ppm): 51.2, 55.8, 66.1, 115.2, 121.7, 139.0,
161.2, 197.1.
arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm): 24.0, 25.7,
26.4, 52.1, 53.1, 129.5, 130.3, 131.6, 137.4, 194.0.
3.9 | p-Tolyl piperidine-
1-carbodithioate (6a)[39]
Yellow solid, mp 115–118ꢀC. IR (KBr): 1,171, 1,592,
3.7 | 4-Chlorophenyl morpholine-
2,852, 2,935, 2,994 cmÀ1
.
4-carbodithioate (4a)[20]
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.62–1.70 (m,
6H, 3CH2), 2.37 (s, 3H, CH3), 4.00–4.21 (m, 4H, 2CH2),
7.27 (d, J = 8.3 Hz, 2H, arom), 7.31 (d, J = 8.3 Hz, 2H,
arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm): 21.4, 24.0,
25.7, 26.4, 52.0, 53.1, 128.2, 130.2, 137.3, 140.2, 194.5.
Yellow solid, mp 111–113ꢀC. IR (KBr): 1,176, 1,570,
2,853, 2,920 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 3.73 (t,
J = 4.9 Hz, 4H, 2CH2), 4.06–4.20 (broad, 4H, 2CH2), 7.46
(d, J = 8.4 Hz, 2H, arom), 7.55 (d, J = 8.6 Hz, 2H, arom).
13C NMR (75 MHz, DMSO-d6) δ (ppm): 51.9, 66.1, 129.7,
130.1, 135.8, 139.1, 195.2.
3.10 | 4-Methoxyphenyl piperidine-
1-carbodithioate (7a)[39]
White solid, mp 93–96ꢀC. IR (KBr): 1,246, 1,590, 2,852,
3.8 | Phenyl piperidine-
2,921, 2,997 cmÀ1
.
1-carbodithioate (5a)[38]
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.62–1.68 (m,
6H, 3CH2), 3.83 (s, 3H, OCH3), 4.00–4.21 (m, 4H, 2CH2),
7.02 (d, J = 8.5 Hz, 2H, arom), 7.34 (d, J = 8.3 Hz, 2H,
arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm): 24.0, 25.7,
26.4, 51.9, 53.2, 55.8, 115.1, 115.5, 122.3, 132.5, 139.0,
161.1, 195.3.
Yellow solid, mp 110–112ꢀC. IR (KBr): 1,226, 1,576,
2,852, 2,926, 2,988 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.63–1.68 (m,
6H, 3CH2), 4.02–4.22 (m, 4H, 2CH2), 7.42–7.51 (m, 5H,

BAGHERI ET AL.
11
3.11 | 4-Chlorophenyl piperidine-
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.89–2.12 (m,
4H, 2CH2), 3.73–3.79 (m, 4H, 2CH2), 7.45 (d, J = 8.5 Hz,
2H, arom), 7.54 (d, J = 8.6 Hz, 2H, arom). 13C NMR
(75 MHz, DMSO-d6) δ (ppm): 24.4, 26.4, 51.5, 55.8, 129.6,
130.2, 135.6, 138.8, 190.3.
1-carbodithioate (8a)[20]
Yellow solid, mp 85–88ꢀC. IR (KBr): 1,223, 1,569, 2,851,
2,936 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.64–1.67 (m,
6H, 3CH2), 3.99–4.20 (m, 4H, 2CH2), 7.43 (d, J = 8.5 Hz,
2H, arom), 7.52 (d, J = 8.5 Hz, 2H, arom). 13C NMR
(75 MHz, DMSO-d6) δ (ppm): 24.0, 25.6, 26.5, 52.2, 53.2,
129.5, 130.6, 135.6, 139.1, 193.3.
Anal. Calcd. For C11H12ClNS2: C, 51.25; H, 4.69; N,
5.43; S, 24.87%. Found. C,51.53; H, 4.60; N, 5.50; S, 24.90%.
4 | CONCLUSIONS
3.12 | Phenyl pyrrolidine-
In summary, SEP clay was utilized to synthesize the mag-
netically recyclable and highly efficient SEP/Fe3O4/CuO
nanocomposite. The catalytic activity of the prepared
nanocomposite was tested in the reaction of phenyl
iodide, secondary amines, and CS2 for the synthesis of S-
aryl dithiocarbamates. Various S-aryl dithiocarbamates
were synthesized under benign reaction conditions while
offering satisfactory yield. The ICP analysis results
showed a negligible Cu leaching for the catalyst during
the reaction process, proving that the heterogeneous cata-
lyst is stable and very active under the applied conditions.
As a result, the advantages offered by this procedure are
as follows: operational simplicity, use of cheap copper
catalyst, good product efficiency, short reaction time, and
providing recyclability of catalyst up to three times with-
out considerable loss in efficiency. Additionally, the cata-
lyst could be easily separated from the reaction mixture
by using an external magnet.
1-carbodithioate (9a)[38]
Yellow solid, mp 92–94ꢀC. IR (KBr): 1,158, 1,577, 2,870,
2,960 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.89–2.13 (m,
4H, 2CH2), 3.77 (t, J = 6.9 Hz, 4H, 2CH2), 7.45–7.51
(m, 5H, arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm):
24.3, 26.3, 51.5, 55.7, 129.5, 130.4, 131.2, 137.1, 191.0.
3.13 | P-Tolyl pyrrolidine-
1-carbodithioate (10a)
Yellow solid, mp 118–120ꢀC. IR (KBr): 1,177, 1,592,
2,866, 2,963 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.89–2.13 (m,
4H, 2CH2), 2.37 (s, 3H, CH3), 3.77 (t, J = 7.1 Hz, 4H,
2CH2), 7.28 (d, J = 8.2 Hz, 2H, arom), 7.32 (d, J = 8.3 Hz,
2H, arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm): 21.4,
24.3, 26.3, 51.4, 55.7, 127.8, 130.2, 137.0, 140.2, 191.5.
Anal. Calcd. For C12H15NS2: C, 60.72; H, 6.37; N,
5.90; S, 27.01%. Found. C, 60.35; H, 6.42; N, 5.95; S, 27.21%.
ACKNOWLEDGMENTS
The authors express appreciation to the Shahid Bahonar
University of Kerman Faculty Research committee for its
support of this investigation.
REFERENCES
3.14 | 4-Methoxyphenyl pyrrolidine-
[1] D. S. Surry, S. L. Buchwald, Chem. Sci. 2010, 1, 13.
[2] F. Monnier, M. Taillefer, Angew. Chem. Int. Ed. 2009, 48,
6954.
1-carbodithioate (11a)[40]
Yellow solid, mp 102–104ꢀC. IR (KBr): 1,161, 1,590,
[3] S. V. Ley, A. W. Thomas, Angew. Chem. Int. Ed. 2003, 42, 5400.
[4] S. F. Nielsen, E. Ø. Nielsen, G. M. Olsen, T. Liljefors, D.
Peters, J. Med. Chem. 2000, 43, 2217.
[5] H. R. Dasgupta, S. Mukherjee, P. Ghosh, Prog. Chem. Biochem.
Res. 2020, 24, 57.
[6] D. Prasad, A. B. Naidu, G. Sekar, Tetrahedron Lett. 2009, 50,
1411.
[7] S. Ranjit, R. Lee, D. Heryadi, C. Shen, J. E. Wu, P. Zhang,
K. W. Huang, X. Liu, J. Org. Chem. 2011, 76, 8999.
[8] K. Mouri, A. Wakamiya, H. Yamada, T. Kajiwara, S.
Yamaguchi, Org. Lett. 2007, 9, 93.
2,871, 2,956, 3,010 cmÀ1
.
1H NMR (300 MHz, DMSO-d6) δ (ppm): 1.91–2.10 (m,
4H, 2CH2), 3.74–3.78 (m, 4H, 2CH2), 3.82 (s, 3H, OCH3),
7.03 (d, J = 8.3 Hz, 2H, arom), 7.34 (d, J = 8.2 Hz, 2H,
arom). 13C NMR (75 MHz, DMSO-d6) δ (ppm): 24.3, 26.4,
51.3, 55.7, 55.8, 115.1, 121.9, 138.7, 161.1, 192.1.
3.15 | 4-Chlorophenyl pyrrolidine-
1-carbodithioate (12a)
[9] M. P. Samant, R. White, D. J. Hong, G. Croston, P. M. Conn,
J. A. Janovick, J. Rivier, J. Med. Chem. 2007, 50, 2067.
[10] D. J. Prasad, G. Sekar, Org. Lett. 2011, 13, 1008.
Yellow solid, mp 105–108ꢀC. IR (KBr): 1,178, 1,593,
ꢀ
[11] E. Godin, J. Santandrea, A. Caron, S. K. Collins, Org. Lett.
2,867, 2,963 cmÀ1
.
2020, 22, 5905.

12
BAGHERI ET AL.
[12] J. Li, S. Yang, W. Wu, H. Jiang, Org. Chem. Front. 2020, 7,
1395.
[31] A. Tabak, E. Eren, B. Afsin, B. Ü. Caglar, J. Hazard Mater.
2009, 161, 1087.
[13] C. E. Brigham, C. A. Malapit, N. Lalloo, M. S. Sanford, ACS
Catal. 2020, 10, 8315.
[32] S. Yu, X. Liu, G. Xu, Y. Qiu, L. Cheng, Desalin. Water Treat.
2016, 57, 16943.
[14] T. Wang, J. Chen, J. Wang, S. Xu, A. Lin, H. Yao, S. Jiang, J.
Xu, Org. Biomol. Chem. 2018, 16, 3721.
[33] M. Fayazi, D. Afzali, M. A. Taher, A. Mostafavi, V. K. Gupta,
J. Mol. Liq. 2015, 212, 675.
[15] A. Correa, O. G. Mancheño, C. Bolm, Chem. Soc. Rev. 2008, 37,
1108.
[34] W. Zhang, X. Li, R. Zou, H. Wu, H. Shi, S. Yu, Y. Liu, Sci. Rep.
2015, 5, 11129.
[16] M. D'hooghe, N. De Kimpe, Tetrahedron 2006, 62, 513.
[17] C. Rafin, E. Veignie, M. Sancholle, D. Postel, C. Len, P. Villa,
G. Ronco, J. Agric. Food Chem. 2000, 48, 5283.
[18] I. Almeida, V. C. Ferreira, M. F. Montemor, L. M. Abrantes,
A. S. Viana, Electrochim. Acta 2012, 83, 311.
[19] Y. Qin, S. Liu, R. Xing, H. Yu, K. Li, X. Meng, R. Li, P. Li, Car-
bohydr. Polym. 2012, 89, 388.
[20] F. Aryanasab, RSC Adv. 2016, 6, 32018.
[21] P. M. Madalageri, O. Kotresh, J. Chem. Pharm. Res. 2012, 4,
2697.
[35] F. Li, X. Liu, Q. Zhang, T. Kong, H. Jin, Cryst. Res. Technol.
2012, 47, 1140.
[36] H. Sharghi, I. Ghaderi, M. M. Doroodmand, Appl. Organomet.
Chem. 2017, 31, 11550.
[37] M. Fayazi, D. Afzali, R. Ghanei-Motlagh, A. Iraji, Environ. Sci.
Pollut. Res. 2019, 26, 18893.
[38] H. Sharghi, I. Ghaderi, M. M. Doroodmand, Appl. Organomet.
Chem. 2017, 31, 3869.
[39] T. Chatterjee, S. Bhadra, B. C. Ranu, Green Chem. 2011, 13,
1837.
[22] D. Zhang, J. Chen, Y. Liang, H. Zhou, Synth. Commun. 2005,
35, 521.
[40] F. Nemati, A. Elhampour, S. Zulfaghari, Phosphorus Sulfur Sil-
icon Relat. Elem. 2015, 190, 1692.
[23] W. Chin-Hsien, Synth. 1981, 8, 622.
[24] H. Tilles, J. Am. Chem. Soc. 1959, 81, 714.
[25] B. M. Asgari, Prog. Chem. Biochem. Res. 2020, 4, 20.
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.
́
[26] A. Corma, H. Garcıa, A. Leyva, A. Primo, Appl. Catal. A Gen.
2004, 257, 77.
[27] R. J. Kalbasi, A. R. Massah, B. Daneshvarnejad, Appl. Clay Sci.
2012, 55, 1.
[28] M. Zendehdel, M. A. Bodaghifard, H. Behyar, Z. Mortezaei,
Microporous Mesoporous Mater. 2018, 266, 83.
[29] R. Dong, D. Chen, N. Li, Q. Xu, H. Li, J. He, J. Lu, Chemo-
sphere 2020, 239, 124708.
[30] V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara,
J. M. Basset, Chem. Rev. 2011, 111, 3036.
How to cite this article: F. H. Bagheri,
H. Khabazzadeh, M. Fayazi, J Chin Chem Soc 2021,
1. https://doi.org/10.1002/jccs.202100049