Copper iodide nanoparticles-decorated porous polysulfonamide gel: As effective catalyst for decarboxylative synthesis of N-Arylsulfonamides

Article abstract of DOI:10.1002/aoc.5449

A porous cross-linked poly (ethyleneamine)-polysulfonamide (PEA-PSA) as a novel organic support system is synthesized in the presence of silica template by nanocasting technique. The paper demonstrates immobilization of CuI nanoparticles inside the pores (PEA-PSA?CuI) for the facile recovery and recycling of these nanoparticles. The presence of porous PEA-PSA and PEA-PSA?CuI nanocomposites was confirmed using FT-IR spectroscopy, FE-SEM, EDX, TGA, XRD, TEM, BET, XPS, WDX, ¹H NMR, and ICP-OES techniques. The PEA-PSA?CuI along with Ag(I)/K₂S₂O₈ was implemented as a reusable cooperative catalyst-oxidant system in the N-arylation of p-toluenesulfonamide with substituted carboxylic acids in mild condition. So, the novel decarboxylative cross-coupling catalyzed by copper and silver has been developed. Aromatic, secondary and tertiary aliphatic acids underwent high efficient decarboxylative processes with p-toluenesulfonamide to afford the corresponding products. This method provides a practical approach for the flexible synthesis of sulfonamides from the readily affordable substrates. The catalyst is highly reusable and efficient, especially in terms of time and yield of the desired product.

Full text of DOI:10.1002/aoc.5449

Received: 6 October 2019
DOI: 10.1002/aoc.5449
Revised: 16 November 2019
Accepted: 29 November 2019
F U L L P A P E R
Copper iodide nanoparticles-decorated porous
polysulfonamide gel: As effective catalyst for
decarboxylative synthesis of N-Arylsulfonamides
Sedigheh Alavinia1
Jaber Yousefi Seyf3
| Ramin Ghorbani-Vaghei1
| Iman Ali Arabian1
| Jamshid Rakhtshah2
|
1Department of Organic Chemistry,
Faculty of Chemistry, Bu-Ali Sina
University, 65174, Hamedan, Iran
2Department of Inorganic Chemistry,
Faculty of Chemistry, University of
Tabriz, Tabriz, Iran
A porous cross-linked poly (ethyleneamine)-polysulfonamide (PEA-PSA) as a
novel organic support system is synthesized in the presence of silica template
by nanocasting technique. The paper demonstrates immobilization of CuI
nanoparticles inside the pores (PEA-PSA@CuI) for the facile recovery and
recycling of these nanoparticles. The presence of porous PEA-PSA and PEA-
PSA@CuI nanocomposites was confirmed using FT-IR spectroscopy, FE-SEM,
3Department of Chemical Engineering,
University of Technology, Hamedan, Iran
1
EDX, TGA, XRD, TEM, BET, XPS, WDX, H NMR, and ICP-OES techniques.
Correspondence
The PEA-PSA@CuI along with Ag(I)/K2S2O8 was implemented as a reusable
cooperative catalyst-oxidant system in the N-arylation of p-toluenesulfonamide
with substituted carboxylic acids in mild condition. So, the novel
decarboxylative cross-coupling catalyzed by copper and silver has been devel-
oped. Aromatic, secondary and tertiary aliphatic acids underwent high effi-
cient decarboxylative processes with p-toluenesulfonamide to afford the
corresponding products. This method provides a practical approach for the
flexible synthesis of sulfonamides from the readily affordable substrates. The
catalyst is highly reusable and efficient, especially in terms of time and yield of
the desired product.
Ramin Ghorbani-Vaghei, Department of
Organic Chemistry, Faculty of Chemistry,
Bu-Ali Sina University, 65174, Hamedan,
Iran.
Email: rgvaghei@yahoo.com
K E Y W O R D S
C-N coupling, Cross-linked polysulfonamide, Decarboxylative, Heterogeneous, Porous
1 | INTRODUCTION
abundance in nature as very sensitive organometallic
reagents. Other advantages of these acids are their facile
Owing to the recent advances in N-arylation coupling
reactions through transition metal catalysis, several
effective methods have been proposed for the selective
bond formation of carbon-heteroatom.[1–3] In this regard,
N-Arylsulfonamides have various antibacterial,[4]
antitumor,[5] and anti-HIV biological activities.[6] Aryl
halides and aryl boronic acids can produce various prod-
ucts as primary substrates in the presence of strong bases
or harsh reaction conditions.[7,8] Carboxylic acids are
among the widely used coupling partners because of their
handling, the release of CO2 as the waste product, and
high regioselectivity at the carboxylic acid position in
comparison to C–H.[9]
Decarboxylation of carboxylic acids is a promising
coupling partner in organic synthesis. These acids are
very useful in creating a bond between an aryl ring and a
heteroatom generating similar organometallic intermedi-
ates followed by decarboxylation in organic synthesis.[10]
In this regard, strategies such as Minisci reactions and
Hunsdiecker decarboxylation are among the most
Appl Organometal Chem. 2020;e5449.
wileyonlinelibrary.com/journal/aoc
© 2020 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.5449

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ALAVINIA ET AL.
important decarboxylations interactions with silver
salts.[11,12] Nevertheless, the Hunsdiecker protocol has a
moderate yield and narrow reaction scopes and requires
anhydrous silver salts.[13] The Minisci reaction is one of
the most effective approaches for functionalization of
electron-poor heterocycles.[14–16] Because of the interest-
ing properties of silver(I) salts and its oxidant complexes,
they are widely used in producing carbon and
heteroatom-centered radicals.[17] Traditionally, the com-
bination of peroxydisulfate and silver(I) has been applied
in the Minisci reaction for organic synthesis. This method
provides an efficient and direct means to substitute (het-
ero) arene compounds such as acylation, arylation and
fluorination.[18] Although these precursors have numer-
ous advantages, it is still difficult to design new protocols
from them for dealing with the mentioned issues. Hence,
designing new protocols for decreasing the use of addi-
tives, toxic reaction media, and homogeneous or expen-
sive catalysts is still a challenging issue.
Gels are three-dimensional networks of cross-linked
polymers built based on the molecular structure that
can absorb different solvents. Cross-linking is consid-
ered as an important class of procedures because of its
promising role in the modification of polymer net-
works and three-dimensional extensions of polymeric
structures.[19,20] New gel structures fabricated using
organic material via templates have recently attracted
the attention of many researchers. The chemical syn-
thesis procedure with the incorporation of template
synthesis and self-organization can be used for struc-
turing materials with extension scales. These materials
have found great use in the primary and applied
research such as sorbents for the adsorption of gas and
the removal of organic compounds from water.[21]
Owing to the attractive properties arising from the spe-
cific features of both polymers and porous gels, design
and synthesis of new porous polymer gels have
received considerable attention. The functional porous
polymers are fabricated at a molecular level by control-
ling the surface area and applying a superior pore
topology. Major techniques applied for preparation of
new porous structures are nanocasting method, block
copolymer self-assembly, and direct synthesis.[22]
Among these techniques, combining self-assembly with
the nanocasting methods have shown a high potential
for the direct replication of the inverse structure of the
preformed templates. These pathways use hard tem-
plates to create porous polymers that can incorporate
several chemical functionalities at the pore surface.[22]
Compared with metals and inorganic species, poly-
meric supports are excellent candidates for the design
of powerful catalysts because of their ease of handling
and processing.[23] The coating of the polymer struc-
ture is usually incomplete. In addition, the arrange-
ment of the NPs is irregular.[24] To avoid these
limitations and develop new methods for the synthesis
of composite porous structures, the exploration of
novel methodologies that control these parameters is
still ongoing. Development of application of sulfon-
amide in coordination chemistry, medicinal chemistry,
and catalytic fields has attracted the interest of many
researchers.[25] Porous polysulfonamides are prepared
from polymerization on the surface of silica template.
The surfaces of porous cross-linked polysulfonamides
must be modified using the transition metal precursors
such as copper, which introduces new properties and
applications (Figure 1).[26] CuI NPs have received a great
deal of attention owing to their unique characteristics
including nanometric size, large surface area, and better
yields of products, particularly in multi-component reac-
tions.[27] Thus, the use of porous cross-linked pol-
ysulfonamide as new support for the stabilization of CuI
NPs for designing a new applied organometallic catalyst
bearing both active Lewis acid and porous sites is an
essential task for organic chemists. Despite reported
copper-catalyzed couplings of sulfonamides with aryl
FIGURE 1 a) Three dimensional,
and b) the contour of the reaction yield
versus temperature and amount of the
catalyst

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
3 of 18
halides by Wu[28] and Buchwald,[8] these reactions occur
under harsh reaction conditions and at high tempera-
tures.[29] Another important problem is the need for stoi-
chiometric amount of metal catalyst and using arene
carboxylic acids, which restricts their potential applica-
tion. Therefore, the development of decarboxylative cou-
plings that are capable of coupling alkyl carboxylic acids
in a catalytic manner is of great necessity. In the present
study, considering the interesting properties of the porous
polymer-based catalysts and pursuing our recent study on
porous materials as catalysts in multicomponent
reaction,[30] we investigated the synthesis of a stable
multifunctional catalyst bearing active Lewis acid groups
(PEA-PSA@CuI). The PEA-PSA@CuI along with Ag(I)/
K2S2O8 was implemented as a reusable cooperative
catalyst-oxidant system for selective arylation or
Avance spectrometers 250 MHz for 1H NMR and 63 MHz
for 13C NMR using TMS as an internal standard; chemi-
cal shifts were expressed in parts per million (ppm).
Infrared (IR) spectroscopy was conducted on a Perkin
Elmer GX FT-IR spectrometer. Mass spectra were
recorded on a Shimadzu QP 1100 BX Mass Spectrometer.
Melting points were determined on a Stuarf Scientific
SMP3 apparatus. Powder X-ray diffraction (PXRD) pat-
terns recorded on a Rigaku XDS 2000 diffractometer
using nickel-filtered CuKa radiation (λ =1.5418) over a
range of <50ꢀ. Thermo-gravimetric analysis (TGA) was
performed on a PYRIS DIAMOND instrument. Induc-
tively coupled plasma-atomic emission spectroscopy
(ICP-AES) was conducted on a Varian Vista MPX ICP-
AES instrument. The sample was digested in conc.
H2SO4: 30% aq. H2O2 (3:1 v/v) and heated until the solu-
tion became clear and colourless. The qualitative analysis
of PEA-PSA@CuI was performed by using energy-
dispersive X-ray spectroscopy (EDS). Scanning electron
microscopy (SEM) was performed on EM3200 instrument
operated at 30 kV accelerating voltage. For morphology
observation, organogels that swell to equilibrium at 25 ꢀC
were freeze-dried in a freeze-dry system (LANCONCO)
to remove ethanol completely. After drying, the gel sam-
ples were sputter coated with gold, and structures and
morphologies of the gel surfaces were then visualized by
a scanning electron microscope (Hitachi-X650). Trans-
mission electron microscopy (TEM) was performed using
a Zeiss-EM10C-100kv. Prior to the surface area analysis,
the samples were activated in a high vacuum at 80 ꢀC for
12 hr. All adsorption and desorption measurements were
performed on a Micromeritics TriStar 3020 version 3.02
(N2) system and measured at 77 K. The data were ana-
lyzed using the TriStar II 3020 V1.03 software
(Micromeritics, Norcross, GA). The pore size distribu-
tions were calculated from the adsorption–desorption iso-
therms. Wavelength-dispersive X-ray spectroscopy
(WDX) was performed using a TESCAN mira3. The
chemical surface composition of the copper
nanocomposite was determined by XPS (BesTec, Berlin,
Germany).
alkenylation
of
p-toluenesulfonamide
through
decarboxylative cross-couplings of substituted aliphatic
carboxylic acids (Scheme 1). Although polysulfonamide
represents a potential application as a substrate in the
field of the catalyst,[25] there is no report on the porous
polysulfonamide or cross-linked polysulfonamide as a
substrate in the area of the catalyst. Moreover, porosity,
as a microstructured reactor, is a good characteristic to
pre-concentrate substrates and enhance catalytically
accessible active sites in order to increase reaction rate
and product yield.[26] The other advantages of porous
polysulfonamides as a catalyst support are included the
low price of catalyst, easy to synthesis and the availability
of monomers. The C-N coupling reaction could proceeds
using catalytic amount of metals and both substrates are
cheap and available.
2 | EXPERIMENTAL SETUP
2.1 | Chemicals and instruments
All commercially available chemicals were obtained from
Merck and Fluka companies and used without further
purification otherwise stated. Nuclear magnetic reso-
nance (NMR) spectra were recorded in CDCl3 on Bruker
2.2 | Synthesis of Benzene-1,3-
disulfonylchloride
PCl5 (16.5 mmol), as chlorination agent, was added to the
sodium salt of benzene-1,3-disulfonic acid (5.00 g,
18 mmol). To initiate the reaction, the vessel was heated
ꢀ
(40–50 C), then the reaction continues autonomously.
After complete conversion (2 hr), crushed ice (100 g) and
CHCl3 (100 ml) was added and the organic layer was
separated.[31]
SCHEME 1 CuI/Ag-catalyzed decarboxylative C–N cross-
coupling reaction

4 of 18
ALAVINIA ET AL.
2.3 | Synthesis of SiO2 NPs
2.7 | Preparation of porous PEA-
PSA@CuI gel
SiO2 nanoparticles, with an average diameter of 20 nm,
were synthesized in ethanol according to the Stöber
method.[32] In summary, 100 ml ethanol, 21.6 ml
deionized water, and 2.9 mL aqueous ammonia were
added in a round bottom flask and stirred at ambient
temperature for 10 min. Next, about 4.5 mL TEOS was
slowly added to the solution by a syringe within 30 min
and the reaction was kept on for 10 hr. The SiO2 NPs
were separated by centrifugation, rinsed with water and
ethanol, then dried under vacuum conditions at 80 ꢀC for
12 hr.
For loading CuI NPs, to an aqueous solution of CuI NPs
in the H2O (0.05 g in 20 ml), 0.1 g of the prepared poly-
meric support was added into the mixture for 12 hr while
magnetically stirring. Afterward, the solid particles were
separated, washed, with ethanol (2 × 25 mL) and water
(2 × 25 mL) and dried at 50 ꢀC. Finally, the porous PEA-
PSA@CuI nanoparticles were collected, washed with
water, separated through centrifugation, and dried under
vacuum. The concentration of copper in the polymeric
catalyst was 0.7 mmol/g determined by ICP-OES.
2.4 | Synthesis of SiO2/PEA-PSA
2.8 | Experimental design
nanocomposite gel
The design of experiment (DOE), on the other hand, was
used as a systematic approach to find the optimum reac-
tion condition, including temperature and the amount of
catalyst. Optimization shows that the optimum reaction
The SiO2 NPs (0.05 g) were treated with benzene-1,-
3-disulfonyl chloride (1 mmol), ethane-1,2-diamine
(NH2CH2CH2NH2) (0.7 mmol) and tris(2-aminoethyl)
amine (N (CH2CH2NH2)3 (0.2 mmol) as follows: SiO2
NPs was dispersed homogeneously in 30 mL of chloro-
form using the ultrasonication technique. After stirring at
room temperature for 6 hr, a poly-sulfonamide silane-
modified SiO2 NPs (SiO2/PEA-PSA NPs) gel was
obtained. The gel was filtered off and washed with chlo-
roform (20 mL) in triplicate and then dried under vac-
uum conditions at room temperature for 12 hr.
ꢀ
conditions are 110 C, and 0.05 g, for temperature and
the amount of catalyst (PEA-PSA@CuI), respectively.
The Central Composite Design (CCD), in summary, as an
efficient response surface method in experimental design
methodology was used to design the reactions to be car-
ried out at laboratory. In our representative reaction
(decarboxylative cross-coupling of benzoic acid with p-
toluenesulfonamide), temperature (X1) and the amount
of catalyst (X2) were chosen as the two main factors that
would affect the reaction yield (Y). To investigate curva-
ture in the reaction yield, three replicate at center point
were applied, if there is one. The levels of the X1 and X2
and the corresponding response values (reaction yield)
are given in Table 1. Analysis of variance (ANOVA)
reveals that a quadratic model best fits to the experimen-
tal data. The analysis of variance is summarized in
Table 2. The coefficient of determination (R2) for the
yield is 0.9997, which represents the good agreement
between experimental reaction yields and yield obtained
from quadratic model. The p-values imply that the model
results are not due to chance. The smaller the p-value,
the more the significant terms in the reaction yield.
Expression (1) shows the relation between representa-
tive reaction yield, temperature and the amount of the
as-prepared catalyst:
2.5 | Synthesis of porous PEA-PSA gel
The silica template of the silica@polysulfonamide
nanocomposite prepared in the previous section was
removed selectively through etching the SiO2 NPs with
an HF aqueous solution. 0.5 g of SiO2/PEA-PSA NPs and
deionized water (10 ml) were put in a plastic tube and
sonicated for 5 min. Next, HF solution (30 ml, 5 wt%)
was added into the mixture for 6 hr while magnetically
stirring. The created porous gels were washed with etha-
nol, dried at 50 ꢀC, and sieved through an 80 mesh
screen.
2.6 | Synthesis of CuI NPs
CuI NPs were obtained by treating the solution of CuSO4
(1 mmol) with the solution of KI (2 mmol) in 40 ml of
distilled water. The solution of CuSO4 was gradually sub-
merged into a solution of KI and then sonicated for
30 min. The nanoparticles were separated, rinsed with
water (2 × 25 ml), and dried.[33]
Yield = 28:12−0:05X1-106:09X2 + 5:31X1X2 + 3:37
ð1Þ
× 10−3X12 + 986:84X22
Terms that have minus and plus sign, generally, have
increasing and decreasing effect on the reaction yield,

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
5 of 18
TABLE 1 Levels of the experimental variables and the
corresponding response values using the CCD method
number of effective collisions per unit volume increases,
that is, the reaction yield increases.
dependent
Independent variables
variable
2.9 | Optimization of reaction condition
and validation of the model
X1
X2 (amount of
Runs (temperature) catalyst)
Yield (%)
1
30
70
0.03
0.03
0.05
0.05
0.01
0.03
0.01
0.03
0.01
0.03
0.05
32
50
56
35
68
50
30
50
44
78
90
To find out the optimum values of the temperature and
the amount of catalyst, expression (1) together with
numerical technique were used. Optimization showed
that X1 and X2 should be equal to 110 ꢀC and 0.05,
respectively, which the reaction yield is equal to 89.55%
in these conditions. Of more interest here is the predic-
tive power of the proposed quadratic model. Accordingly,
the representative reaction was carried out at optimum
reaction conditions with three replicate. The mean value
of obtained reaction yield is 90.00%. The deviation
between experimental reaction yield and the yield
obtained by the model is 0.50%. Very low deviation con-
firms the very well predictive power of the obtained
model. Accordingly, the proposed quadratic model can
be trusty used to obtain the reaction yield at each
condition.
2
3
70
4
30
5
110
70
6
7
30
8
70
9
70
10
11
110
110
TABLE 2 Analysis of variance (ANOVA) for the response
surface quadratic model of the reaction yield
Source
p-val. Prob. > F
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
0.2539
2.10 | General procedure for the
synthesis of N-arylsulfonamides
Model (yield)
X1
At the obtained optimum reaction condition by the
DOE, a mixture of carboxylic acid (1.2 mmol), K2S2O8
(1 mmol) in toluene (0.5 mL), p-toluenesulfonamide
(1 mmol), and silver nitrate (1 mol%, 2 mg) along with
X2
X1X2
2
X1
2
ꢀ
X2
PEA-PSA@CuI (3.5 mol%, 0.05 g) was heated (110 C,
R2
0.9997
sealed tube). Once the reaction was completed, the sol-
vent was evaporated and EtOAc (10 mL) was added to
the mixture. Afterward, the nanocatalyst was eliminated
by centrifugation, washed with acetone and water for
Predicted R2
0.9969
Lack of fit
0.4000
ꢀ
several times, and dried at 60 C for 3 hr. In the next
step, water (100 mL) was added and extracted with
EtOAc (30 mL) in triplicate. To obtain the desired sul-
fonamide, the organic layer was dried over MgSO4, fil-
tered, and concentrated in vacuum.
respectively. The absolute magnitude of the coefficient in
the equation (1) determines the extent of the effect.
Figure 1 shows the 3 dimensional and the contour of
reaction yield versus temperature and the amount of cat-
alyst. As Figure 1 illustrates, increase in temperature and
the amount of catalyst increase the reaction yield. All
reactions in the optimization procedure, it should be
emphasized, were ceased after 45 min. From theoretical
point of view (Arrhenius equation), increasing the tem-
perature, results increase in the reaction rate constant,
which, in turn, leads to increase in reaction rate. It is
then clear that the reaction yield increases at a specified
time (45 min). By increasing the amount of catalyst, the
2.11 | Gel content
About 0.5 g of the sample (Wi) was placed in water for
24 hr at room temperature. The swollen part was sepa-
rated by centrifugation and dried in a vacuum oven at
ꢀ
40 C for 24 hr. Eventually, the samples were weighed
(Wf). Here, the gel content (Gel (%)) is defined by
Equation (1):
Gel (%) = Wi/Wf *100 (1).

6 of 18
ALAVINIA ET AL.
1
ꢀ
2.12 | Analytical data of selected
products
Mp: 153–156 C. H NMR (250 MHz, Chloroform) δ
8.00 (d, J = 9.7 Hz, 2H), 7.87–7.56 (m, 2H), 7.31 (d,
J = 8.9 Hz, 2H), 6.66 (d, J = 8.6 Hz, 2H), 4.13 (s, 1H,
NH), 2.24 (s, 3H), 2.20 (s, 3H). 13C NMR (63 MHz, Chlo-
roform) δ 150.91, 130.06, 129.84, 127.85, 127.18, 126.64,
126.06, 124.09, 122.85, 120.00, 113.23, 17.67, 17.18.
N-(2-nitro-4-methoxyphenyl)-4-
N-phenyl-4-methyl-benzenesulfonamide: (compound 3a).
Known compound; mp: 111–112 ꢀC (Lit. mp
109–112 ꢀC)[34]
N-(p-tolyl)-4-methyl-benzenesulfonamide: (compound
3b).
methylbenzenesulfonamide: (compound 3k).
1
Known compound; mp: 101–103 ꢀC (Lit. mp
97–99 ꢀC)[34]
Mp: 92–94 C. IR (KBr): 3281, 1351, 1145 cm−1. H
ꢀ
NMR (250 MHz, Chloroform) δ 9.26 (s, 1H), 7.75 (d,
J = 9.2 Hz, 1H), 7.59 (d, J = 8.3 Hz, 2H), 7.46 (d,
J = 3.0 Hz, 1H), 7.20 (d, J = 8.7 Hz, 2H), 7.15 (d,
J = 3.0 Hz, 1H), 3.80 (s, 3H), 2.35 (s, 3H). 13C NMR
(63 MHz, Chloroform) δ 156.20, 144.63, 139.02, 135.49,
129.92, 127.09, 126.43, 124.62, 122.97, 109.16, 55.98,
21.54.
N-(4-methoxyphenyl)-4-methylbenzenesulfonamide:
(compound 3c).
Known compound; mp: 113–114 ꢀC (Lit. mp
112–114 ꢀC)[34]
N-(4-chlorophenyl)-4-methylbenzenesulfonamide:
(compound 3d).
Known compound; mp: 119–122 ꢀC (Lit. mp
119–122 ꢀC)[34]
4-Methyl-N-(pyridin-2-yl)benzenesulfonamide: (com-
pound 3l).
N-(4-nitrophenyl)-4-methylbenzenesulfonamide: (com-
Known compound; Mp: 214–216 ꢀC (Lit. mp
pound 3e).
214–216 ꢀC),[34] IR (KBr): 3229, 1356, 1140 cm−1 1H
.
Mp: 189–191 C, IR (KBr): 3335, 1339, 1183 cm−1. H
NMR (250 MHz, Chloroform) δ 8.42 (s, 2H), 7.96–7.57
(m, 3H), 7.47 (s, 1H), 7.29 (s, 4H), 6.85 (s, 1H), 2.42 (s,
3H). 13C NMR (63 MHz, Chloroform) δ 157.91, 148.73,
147.54, 144.53, 143.62, 134.18, 131.73, 120.92, 118.76,
26.24. Mass (m/z): 248.
1
ꢀ
NMR (250 MHz, DMSO-d6) δ 8.12 (d, J = 8.8 Hz, 2H),
7.77 (d, J = 7.9 Hz, 2H), 7.37 (d, J = 8.3 Hz, 2H), 7.32 (d,
J = 7.9 Hz, 2H), 2.51 (s, 1H), 2.32 (s, 3H). 13C NMR
(63 MHz, DMSO-d6) δ 144.79, 144.50, 142.94, 136.62,
130.43, 127.23, 125.78, 118.34, 21.41.
4-Methyl-N-(pyrimidin-2-yl)benzenesulfonamide:
(compound 3mꢀ).
N-(2-nitrophenyl)-4-methylbenzenesulfonamide: (com-
1
pound 3f).
Mp:203–205 C, IR (KBr): 3119, 1360, 1168 cm−1. H
Mp: 189–191 C. IR (KBr): 3258, 1314, 1159 cm−1. H
NMR (250 MHz, Chloroform) δ 11.99 (s, 1H), 8.69 (d,
J = 4.9 Hz, 2H), 8.03 (d, J = 8.0 Hz, 2H), 7.31 (d,
J = 8.4 Hz, 2H), 7.01 (t, J = 5.0 Hz, 1H), 2.44 (s, 3H). 13C
NMR (63 MHz, DMSO) δ 158.58, 156.84, 144.16, 136.62,
129.30, 128.48, 115.76, 21.64. Mass (m/z):249.
1
ꢀ
NMR (250 MHz, DMSO-d6) δ 10.21 (s, 1H), 7.91 (d,
J = 8.1 Hz, 1H), 7.63 (m, 3H), 7.37 (d, J = 8.0 Hz, 3H),
7.28 (d, J = 8.6 Hz, 1H), 2.51 (s, 3H). 13C NMR (63 MHz,
DMSO-d6) δ 144.27, 143.35, 136.83, 134.67, 130.96,
130.24, 129.26, 127.32, 126.52, 125.94, 125.61, 21.45.
N-(5-bromopyridin-2-yl)-4-methylbenzenesulfonamide
N-(naphthalen-1-yl)
4-methyl-benzenesulfonamide:
(compound 3n).
1
Mp: 182–183 C, IR (KBr): 3098, 1344, 1165 cm−1. H
ꢀ
(compound 3 h).
Mp: 155–157 C, IR (KBr): 3296, 1303, 1142 cm−1. H
NMR (250 MHz, Chloroform) δ 7.97–7.88 (m, 1H), 7.82
(d, J = 5.9 Hz, 1H), 7.70 (d, J = 8.2 Hz, 2H), 7.5–7.29 (m,
5H), 7.16 (d, J = 7.9 Hz, 2H), 2.34 (s, 3H). 13C NMR
(63 MHz, Chloroform) δ 143.76, 136.42, 134.25, 131.61,
129.56, 128.92, 128.35, 127.38, 127.11, 126.62, 126.27,
125.42, 122.61, 121.70, 21.51.
NMR (250 MHz, Chloroform) δ 10.95(s, 1H), 8.99 (s, 1H),
7.74 (dod, 10 Hz, 7.5 Hz, 2H), 7.40 (d, J = 7.5 Hz, 2H),
7.26 (d, J = 7.5 Hz, 2H), 2.42 (s, 3H). 13C NMR (63 MHz,
Chloroform) δ 150.19, 149.18, 144.33, 141.79, 136.37,
129.92, 127.12, 114.54, 113.41, 21.60. Mass (m/z):326.
N-(2,6-dichlorophenyl)-4-methylbenzenesulfonamide:
(compound 3o).ꢀ
1
ꢀ
1
N-(4-chloro-3-nitrophenyl)-4-
Mp: 136–137 C, IR (KBr): 3268, 1342, 1166 cm−1. H
Methylbenzenesulꢀfonamide: (compound 3i).
NMR (250 MHz, Chloroform) δ 7.79–7.65 (m, 1H), 7.28
(d, J = 7.8 Hz, 1H), 7.20 (d, J = 8.5 Hz, 1H), 7.08–6.94 (m,
1H), 2.42 (s, 1H). 13C NMR (63 MHz, Chloroform) δ
144.61, 135.68, 134.56, 133.62, 130.13, 129.86, 127.28,
125.68, 122.92, 121.78, 21.61. Mass (m/z):316.
1
Mp: 162–164 C. IR (KBr): 3232, 1372, 1138 cm−1. H
NMR (250 MHz, Chloroform) δ 7.70 (d, J = 7.9 Hz, 2H),
7.45 (s, 1H), 7.27 (d, 2H, J = 8.3 Hz), 7.20 (d, J = 8.6 Hz,
2H), 7.06 (d, J = 8.4 Hz, 2H), 2.40 (s, 3H, CH3). 13C NMR
(63 MHz, Chloroform) δ 144.24, 135.62, 135.30, 130.71,
129.82, 129.38, 127.32, 122.74, 21.56. Mass (m/z): 326.
N-(4-methyl-2-nitrophenyl) 4-ethylbenzenesulfonamide:
(compound 3j).
2-Methyl-N-tosylpropan-2-amine: (compound 3p).
1
Mp: 108–111 C, IR (KBr): 3268, 1308, 1138 cm−1. H
ꢀ
NMR (250 MHz, Chloroform) δ: 2.16 (s, 9H), 2.37 (s, 3H),
5.39 (d, J = 11.25 Hz, 1H), 7.24(d, J = 7.25 Hz, 2H),

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
7 of 18
7.68(d, J = 7.25 Hz, 2H). 13C NMR (63 MHz, Chloroform)
δ: 142.68, 140.63, 129.42, 126.92, 77.63, 77.12, 76.61,
54.39, 30.04, 21.45. Mass (m/z): 227.
The typical FT-IR spectra of SiO2/PEA-PSA (a),
porous PEA-PSA (b), and PEA-PSA@CuI (c) are shown
in Figure 3. The characteristic peak of SiO2 at 1112 cm−1
is ascribed to Si-O stretching vibrations of silica
nanoparticles trapped in polymer chains.[35] This peak
does not appear in the FT-IR spectra of the PEA-PSA and
CuI@PEA-PSA (Figures 3b and 3c). In the spectrum of
PEA-PSA, the absorption bands at 1334 and 1163 cm−1
are indexed to the S=O stretching vibrations
(Figure 3b).[25] After the coordination of CuI
nanoparticles to these situations, the S=O bonds shifted
to lower wavenumber (i.e., 1327 and 1152 cm−1) in the
spectrum of the final product (Figure 3c). As can be
inferred from these changes, the metal ions are coordi-
nated with the oxygen donor atoms of the PEA-PSA as a
ligand.
N-cyclohexyl-4-methylbenzenesulfonamide:
pound 3q).
(com-
Mp:85–87 ꢀC, IR (KBr): 3307, 1304, 1159 cm−1. H
NMR (250 MHz, Chloroform) δ 1.11 (m, 5H), 1.44 (d,
J = 7 Hz, 1H), 1.61 (m, 4H), 2.37 (s, 3H), 3.04 (s, 1H),
5.40 (d, J = 7 Hz, 1H), 7.24 (d, J = 6.25 Hz, 2H), 7.76 (d,
J = 6.25 Hz, 2H). 13C NMR (63 MHz, Chloroform) δ
142.98, 138.52, 129.57, 126.91, 52.53, 33.67, 25.09, 24.59,
21.46. Mass (m/z): 253.
1
2,3-Dihydro-N-tosylbenzo[b][1,4]dioxin-6-amine (com-
pound 3r).
1
Mp: 193–195 C, IR (KBr): 3239, 1301, 1158 cm−1. H
ꢀ
NMR (250 MHz, DMSO-d6) δ 2.28 (s, 3H), 4.10 (s, 4H),
6.51 (d, J = 8.5 Hz, 1H), 6.56 (s, 1H), 6.67 (d, J = 8.25 Hz,
1H), 7. 28 (d, J = 7 Hz, 2H), 7.57 (d, J = 7 Hz, 2H). 13C
NMR (63 MHz, DMSO-d6) δ 143.51, 140.86, 137.09,
131.41, 130.04, 127.13, 117.66, 114.62, 110.44, 64.49,
64.23, 21.34. Mass (m/z): 305.
Figure 4 illustrates the XRD patterns of PEA-
PSA@CuI. The appearance of peaks at 2θ = 25.6, 29.6,
3 | RESULTS AND DISCUSSION
3.1 | Characterization of immobilized
CuI NPs in porous nanocomposite as a
heterogeneous catalyst
Figure 2 provides a schematic representation of the pre-
pared catalyst. This heterogeneous catalyst was created
through immobilization of CuI NPs in the structure of
porous nanocomposite by complexation with numerous
sulfonamide groups of PEA-PSA and absorbing in the
pores.
FIGURE 3 FT-IR spectra of SiO2/PEA-PSA (a), porous PEA-
PSA (b), and PEA-PSA@CuI (c)
FIGURE 2 A sequence of events in the preparation of loaded CuI NPs in the structure of porous PEA-PSA nanocomposite gel

8 of 18
ALAVINIA ET AL.
illustrates the SEM images of the crosslinked polymer
(a), silica/PEA-PSA (b), and porous PEA-PSA (c-d). The
cross-linked PEA-PSA gel showed a smooth and tight
surface (Figure 5a). Figures 5c-d show SEM images of
PEA-PSA gel obtained from SiO2/PEA-PSA composites
by the selective removal of silica NPs via a chemical etch-
ing. The figure also shows PEA-PSA layered structures
with 3D porous structures. The removal of the template
significantly affected the morphology of the PEA-PSA,
probably due to the creation of porosity on the surface of
the polymer. Cryo-scanning electron microscopy (Cryo-
SEM) was applied to characterize porosity and internal
morphology of freeze-dried porous PEA- PSA gel
(Figure 5c and 5d). For this purpose, lyophilization was
applied in order to induce pore structure into the PEA-
PSA gel. Using liquid nitrogen, the solvent-swollen PEA-
PSA gels were cooled rapidly. In the next step, to create a
porous structure in the gel, the frozen solvent was
removed through sublimation under vacuum behind
voids. The obtained sample shows a uniform 3D porous
network with a large number of pores. The surface of
freeze-dried gel is very loose, which contributes to the dif-
fusion of the solvent into or out of the gel structure dur-
ing the swelling and deswelling of polysulfonamide gels.
FIGURE 4 XRD patterns of PEA-PSA@CuI
42.3, 50.0, 52.4, 61.3, 67.5, 69.5 and 77.2ꢀ is attributed to
CuI species of the catalyst.[33] The XRD patterns clearly
confirm the coating of CuI NPs in PEA-PSA due to the
diffraction peaks of CuI NPs. Also, the XRD pattern of
PEA-PSA@CuI given in Figure 4 shows that SiO2 NPs
have been removed through the silica etching process.
To gain further information about obtained
nanocomposite gels, we investigated its morphological
characterizations with FE-SEM method. Figure
5
FIGURE 5 FE-SEM photographs
of cross-linked PEA-PSA (a), SiO2/PEA-
PSA (b), and freeze-dried porous
PEAPSA gel (c-d)

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
9 of 18
This interconnected nanoscale matrix provides a higher
porosity and active surface area in comparison to agglom-
erated nanoparticles.[36]
The wettability was examined via measuring the con-
tact angle (CA). Figure 6 presents the CAs of water drop-
let sample. Based on the obtained results, the CA
between water and polymers was less than 90ꢀ, which
indicates a good hydrophilicity behavior.[37]
Figure 7 shows the morphology of PEA-PSA@CuI
and CuI NPs as obtained by FE-SEM micrographs. The
figures show a homogeneous nanostructure, proving that
a nanoscale surface was obtained. Moreover, excellent
dispersing of CuI NPs within the gel matrix and the pres-
ence of copper nanoparticles bonded to the organic
matrix in the catalyst were confirmed. It is well known
that PEA-PSA gel can encapsulate the nanoparticles in
the pores and prevent their aggregation (Figure 7a).
Wavelength-dispersive X-ray spectroscopy (WDX) is
an efficient method to generate qualitative data on the
distribution of different chemical elements in the catalyst
matrix. Elemental maps for the synthesized nanocatalyst
are illustrated in Figure 8. As can be seen, C, N, S, O, I,
and Cu are distributed homogeneously, confirming the
FIGURE 6 Contact angles of nanopure water droplets on
PEMA-PSA
FIGURE 7 FE-SEM of PEA-
PSA@CuI nanocomposite (a) and CuI
NPs (b)
FIGURE 8 SEM image of
PEA-PSA@CuI; which shows
the presence of C, N, S, O, Cu
and I atoms in the catalyst

10 of 18
ALAVINIA ET AL.
uniform distribution of nanoparticles in the prepared
sample.
The Brunauer–Emmett–Teller (BET) surface area
analysis was performed to estimate the specific surface
area of PEA-PSA (Figure 11). The N2 isotherm reveal the
After CuI NPs immobilizing in the matrix of PEA-
PSA gel, the uniformly dispersed small CuI NPs was
observed with approximate spherical shape in the TEM
image (Figures 9a and 9b). As can be observed, CuI NPs
distribution is controlled in the presence of PEA-PSA gel
matrix.
ICP-OES analysis was performed to determine the
exact amount of Cu loaded on poly (ethyleneamine)-pol-
ysulfonamide, which was found to be 0.7 mmol per gram
of the catalyst. The high amount of the loaded copper
NPs can be attributed to the gel nature of polymeric sup-
port as well as the presence of large chelating groups on
the nanocomposite. Afterward, energy dispersive spec-
trometer (EDS) was applied to analyze the cross-linked
PEA-PSA (a) and PEA-PSA@CuI (b). The EDS analysis
of PEA-PSA@CuI (Figure 10 b) shows signals of carbon,
oxygen, nitrogen, sulfur, iodine, and copper in the struc-
ture of the nanocomposite gel. The EDS analysis of PEA-
PSA and PEA-PSA@CuI indicates that the Si atom was
removed from the silica particles coated with PEA-PSA
by the HF etching.
FIGURE 11 N2 adsorption–desorption isotherms and the
corresponding pore size distributions for PEA-PSA
FIGURE 9 TEM images of PEA-
PSA@CuI gel with the scale bar of
200 nm (a) and 100 nm (b)
FIGURE 10 The comparison of
EDS analysis of PEA-PSA (a) and PEA-
PSA@CuI (b)

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
11 of 18
TABLE 3 Texture parameters obtained from nitrogen
adsorption studies
typical type IV isotherm with type H3 hysteresis (defined
by IUPAC), which are identified as mesoporous mate-
rials. Table 3 summarizes the results of N2 adsorption–
desorption including pore diameters (DBJH), the BET
surface area (SBET), and the total pore volume (Vtotal) of
the studied samples. (Table 3).
Pore
SBET
(m2 g−1
Pore diameter by
BJH method (nm)
volume
(cm3 g−1
)
Sample
)
PEA-PSA 560
56.36
0.43
TGA curve of PEA-PSA@CuI shown in Figure 12 was
segmented into multiple regions with respect to the mass
loss of the prepared samples. For organic solvents and
ꢀ
physically absorbed water, a mass loss starting at 100 C
is observed. This mass loss at higher temperatures
ꢀ
(250–350 C) is majorly attributed to the loss of organic
groups[25] from the polymeric structure. Additionally,
polymer residue decomposition occurred at the third
mass loss, within the temperature range of 350–600 ꢀC.
The surface turnover of the PEA-PSA@CuI was inves-
tigated by XPS analysis. CuI existence in the PEA-
PSA@CuI was re-confirmed by XPS analysis through
studying binding energy (Figure 13a-b). Figure 13a-b
show XPS spectra of Cu 2p and I 3d core level acquired
FIGURE 12 Thermogravimetric diagram of PEA-PSA@CuI
FIGURE 13 XPS spectra of PEA-PSA@CuI (a) I3d (b) Cu2p (c) C 1 s (d) N 1 s (e) S 2p (f????????) survey spectrum of PEA-PSA@CuI
and (g) O 1 s

12 of 18
ALAVINIA ET AL.
from an as-prepared sample. The peak positions of I 3d,
619.3 eV and 630.8 eV, are in good agreement with the
literature data for CuI material[38] (Figure 13a). The posi-
tions of the peaks of Cu 2p1/2 and 2p3/2 of the sample are
952.2 eV and 932.2 eV, respectively, without the shake-
up, which implies a feature of Cu+ (Figure 13b). The
presence of C, N, S and O in PEA-PSA@CuI sample was
confirmed by the characteristic peaks for C 1 s at binding
energy (BE) of about 284.8 and 285.7 eV (Figure 13c), N
1 s at BE of about 399.7 and 401.8 eV (Figure 13d), and
O1S at BE of about 532.0 eV (Figure 13g) and S 2P at
168.2 and 169.4 eV (Figure 13e). The peak consisting of
168.6 and 169.9 eV corresponds to -C-S(O)-C-sulfone
bridges.[39] Here, the more area in the peak of 168.6 and
169.9 eV indicates that S atom exists as sulfone bridges
step, the effect of PEA-PSA@CuI was investigated and
3.5 mol% of the nanocomposite was the optimal amount
to this reaction and giving 3a in 72% yield (entry 8). Also,
the reaction was tested using CuI salt as the catalyst, but,
in comparison with the prepared catalyst, the obtained
data were not satisfactory and the PEA-PSA@ CuI shows
better performance than CuI salt (6 hr, 50%). Increasing
the amount of CuI/PEA-PSA has no significant effect on
the reaction progress (entry 9). Then, the effect of AgNO3
along with PEA-PSA@CuI was examined and the
coupled product yield was improved (1 hr, 90%) (entry
10). Furthermore, the effect of different solvents was
investigated. The addition of EtOH, H2O, CH3CN to the
reaction system declined the yield of 3a (entries 17–21)
and the best result was obtained in toluene (entry 10).
Here, the oxidant has an important role in this reaction.
In this study, the reaction did not take place in the
absence of persulfate under O2 atmosphere (entry 14).
When the amount of K2S2O8 was 0.5 equivalents, the
yield of the reaction dropped to 45% (entry 13). By using
one equivalent K2S2O8, the yield increased up to 90%.
Also we examined the effect of different oxidants includ-
ing benzoyl peroxide and (NH4)2S2O8 on the progress of
the reaction and the yields of 3a dropped (entries 15–16),
followed by studying the efficacy of AgNO3 on the reac-
tion progress. To our surprise, increasing the AgNO3 to
2 mol% decreased the product yield (entry 12), whereas
decreasing the AgNO3 concentration to 1 mol% increased
the yield. Different bases such as K3PO4, Et3N, K2CO3,
and KOH were applied in this transformation and found
that the reaction in the presence of different bases leads
to reduction in efficiency.
which matches with the -S=O stretch in IR at 1095 cm−1
.
In addition, the characteristic peaks for O1s included
three peaks at 352.0 eV (S–O bonding) indicating that the
CuI NPs was successfully introduced onto the PEA-PSA
surface by bond linkages (Figure 13e). The position of C
1
s
peak is frequently affected by the local
chemical/physical environment around it, and its area
showed two type of nitrogen. The elemental peaks are
dominated by O, S, N, Cu, I and C of nanocomposite gel
(Figure 13f). It can be concluded that PEA-PSA have a
variety of polar groups including alkyl, amine, and sulfo-
nyl. The characteristic peaks related to silica (Si 2p) is not
visible in the XPS elemental survey indicated that the Si
atom was removed from the silica particles coated with
polysulfonamide by the HF etching. Based on the XPS
analysis, a possible structure of PEA-PSA@CuI is given
in the Figure 2.
These results motivated us to examine various aspects
and generality of this approach for different aromatic car-
boxylic acids under optimized conditions. According to
Table 5, a broad substrate scope is observed for both
electron-donating and electron-withdrawing substituents
such as nitro (3e, 3f, 3i, 3j, 3 k), methyl (3b, 3 g, 3j),
chloro (3d, 3i, 3o), bromo (3n), methoxy (3c, 3k), as well
as heterocyclic carboxylic acids such as picolinic acid,
pyrimidine-2-carboxylic acid and 5-bromopicolinic acid
(3l, 3m, 3n), and aliphatic carboxylic acids (3p, 3q).
Overall, these acids provided the desired cross-coupling
products with good to excellent yields. As can be noticed,
due to the difference in decarboxylation rates, the effi-
ciency of the decarboxylative cross-coupling reaction is
influenced by substituents. For instance, in comparison
to para-chloro-substituents, benzoic acids containing a
para-nitro substituent provided more desired results (3d
vs. 3e). Also, it was observed that substituted carboxylic
acids containing electron-withdrawing groups (e.g., nitro
and halogen) reacted faster than carboxylic acids con-
taining electron-donating groups. Moreover, substituted
3.2 | CuI immobilized in poly
(ethyleneamine)-polysulfonamide
nanocomposite catalytic activity
In this section, the catalytic effect of PEA-PSA@CuI and
PEA-PSA@Ag nanocomposite as a catalyst was investi-
gated in the synthesis of 4-methyl-N-phenyl
benzenesulfonamide 3a as a model compound. We chose
the decarboxylative cross-coupling between benzoic acid
(1a) and p-toluenesulfonamide (2a) as a model reaction
commonly used in optimization studies (Table 4). Ini-
tially, the catalytic activity of AgNO3 and PEA-PSA@Ag
was investigated for the synthesis of 3a. The best result
was obtained when using 6 mol% of PEA-PSA@Ag,
which gives 3a in 30% yield (entry 4). Then, we evaluated
the effect of the effect of CuI NPs on the model reaction
progress. According to Table 4, in the presence of
20 mol% CuI NPs along with PEA-PSA@Ag, the yield of
the reaction was increased to 45% (entry 6). In the next

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
13 of 18
TABLE 4 Optimizing the reaction conditions for decarboxylative cross-coupling of benzoic acid with p-toluenesulfonamide reagenta
Entry
1
Cat. (mol%)
Oxidant (eq)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (1)
K2S2O8 (0.5)
Solvent/Time (h)
10/Toluene
10/Toluene
Toluene/10
Toluene/10
Toluene/10
Toluene/5
Toluene/5
Toluene/2
Toluene/2
Toluene/1
Toluene/1
Toluene/1
Toluene/1
Toluene/1
Toluene/1
Toluene/1
EtOH/1
3a (%)
10
12
28
30
30
45
55
72
70
90
89
87
45
0b
AgNO3 (5)
2
AgNO3 (10)
3
PEA-PSA@ Ag (3)
4
PEA-PSA@ Ag (6)
5
PEA-PSA@ Ag (12)
6
PEA-PSA@Ag (6), CuI NPs (10)
PEA-PSA@Ag (6), CuI NPs (20)
PEA-PSA@CuI (3.5)
7
8
9
PEA-PSA@CuI (7)
10
11
12
13
14
15
16
17
18
19
20
21
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (7)
AgNO3 (2), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
AgNO3 (1), PEA-PSA@CuI (3.5)
Benzoylperoxide (1)
(NH4)2S2O8 (1)
K2S2O8 (1)
27
35
10
15
55
60
0b
K2S2O8 (1)
CH3CN/1
DMF/1
K2S2O8 (1)
K2S2O8 (1)
DMSO/1
K2S2O8 (1)
H2O/1
aReaction conditions: 1a (1 mmol), 2a (1.2 mmol), PEA-PSA@CuI (3.5 mol%), AgNO3 (1 mol%), K2S2O8 (1 mmol), toluene (0.5 ml), 110 ꢀC, sealed tube
bThe reaction was not occurred.
carboxylic acids like picolinic acid, pyrimidine-
2-carboxylic acid, and 5-bromopicolinic acid, which are
able to stabilize high-valent silver species,[40] participate
in the decarboxylative cross-coupling reaction and gave
reasonable yields. In this protocol, the position of the
substituent affects the progress of the reaction. Benzoic
acids bearing para-substituents provided larger yields
compared to benzoic acids containing ortho substituents
(3e vs. 3f). Notably, we successfully synthesized new sul-
fonamides using 2,3-dihydrobenzo[b] [1,4] dioxin-
6-carboxylic acid, which has not been reported elsewhere
(3r). Afterward, we extended this protocol to the coupling
of alkyl carboxylic acids with p-toluenesulfonamide. Both
tertiary and secondary aliphatic acids (3q and 3p, respec-
tively) were subjected to high-efficiency decarboxylative-
coupling processes with p-toluenesulfonamide to obtain
the corresponding products in excellent yields. Carboxylic
acid derivatives containing aromatic groups were better
substrates compared with tertiary and secondary carbox-
ylic acids.[41] Primary acids, on the other hand, failed to
proceed under current conditions. The reaction of p-
aminobenzoic acid also was examined and found that the
reaction could not proceed even after prolonged reaction
time. This method was highly high selective for the prod-
ucts. All products were examined using their spectro-
scopic data such as MS, IR, 13C NMR, and 1H NMR.
3.3 | Proposed reaction mechanism
To gain mechanistic insights, additional experiments
were performed. When, the reaction was conducted in

14 of 18
ALAVINIA ET AL.
TABLE 5 Decarboxylative cross-coupling of benzoic acids with p-toluenesulfonamide
aReaction condition: 1 (1.2 mmol), 2 (1 mmol), silver(I) salt (1 mol%), K2S2O8 (1 mmol), PEA-PSA@CuI (3.5 mol%), toluene (0.5 ml), 110 ꢀC, sealed tube,
bIsolated yield.
the presence of radical scavengers, such as 2,6-ditert-
butyl-4-methylphenol (BHT), none of decarboxylative
cross-coupling products were observed. This result sug-
gests that the reaction may involve a radical pathway
(Scheme 2).
SCHEME 2 Radical Scavenger Experiment
The proposed reaction mechanism in the presence of
PEA-PSA@CuI and silver(I)/persulfate is presented in
Scheme 3. It is suggested that copper(I) decarboxylates
the carboxylic acid and produces the aryl radical.[17] We
believed Ag (II) along with Cu (II) can be facilitate the

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
15 of 18
SCHEME 3 Possible reaction
mechanism of N-arylation of p-toluene
sulfonamide with different substituted
carboxylic acids
produce of aryl radical by the assistance of potassium
persulfate. Because in the absence of AgNO3 the yield of
the product was decreased. Also, aromatic ring in carbox-
ylic acid is very important because it could stabilize the
benzyl radical and help the intermediate to finish the
decarboxylative step fast and the final products are rela-
tively stable under the oxydic conditions. The radical sub-
3.4 | Catalyst recycling
Once the reaction was completed, the catalyst was recov-
ered by washing with acetone and water and then oven-
ꢀ
dried at 50 C to be used for six times. The reusability
and catalytic activity of PEA–PSA@CuI were tested for
about six consecutive cycles for the synthesis of 4-methyl-
N-phenylbenzenesulfonamide 3a. The results revealed a
small activity loss even after six cycles (90, 88, 88, 88,
86, and 84 respectively). This observation proves that
there was negligible Cu leaching from the polymeric
supported system, which promotes reusability of the
CuNPs. To determine the exact extent of Cu leaching,
ICP-OES analysis was used, which detected only negligi-
ble Cu leaching (<0.08 ppm) in solution after the 6th
run. Consequently, the CuNPs remained active in repeti-
tive catalytic cycles due to excellent stabilization of Cu
species by the porous polysulfonamid matrix. The SEM
images of the catalyst before and after the reaction reveal-
ing the maintenance of the morphology with nanometric
dimensions after the reaction. The FT-IR analysis of
recycled catalyst showed the stability of the PEA-
PSA@CuI during the recycling procedure (Figure 14).
sequently undergoes
a
substitution step with
sulfonamides to form the final product. As can be seen,
initially, in the nucleophilic coordination step, the sulfon-
amide used throughout the reaction with base generates
the deprotonated nucleophile species and the sulfon-
amide coordinates to Cu(I) forming complex intermedi-
ate A. Subsequently, the silver(I) and copper
(I) decarboxylate carboxylic acid leading to an aryl radical
generation.[18] After oxidation of Cu(I) to Cu (II), the aryl
group transfers to copper species (A) and results in the
formation of intermediate B. Eventually, reductive elimi-
nation of intermediate B leads to the desired product and
regenerates the catalyst (Scheme 3). In another mecha-
nistic pathway, the intermediate C through an oxidative
addition of aryl radical and Cu-based catalyst is gener-
ated, and the second coordination process gives the Cu
(II)-based complex B. Finally, reductive elimination pro-
cess of intermediate B yields the desired products and
regenerates the catalyst. It is worth mentioning that com-
pared with cross-coupling reactions catalysed by Pd(0),
the oxidative addition step occurs before the trans metal-
ation step. But in the copper catalysed cyclic system both
of the routes of Scheme 3 are acceptable (due to the
unpredictability of the relative order of these two
steps).[40,42]
3.5 | Efficiency comparison of the
catalytic activity
According to the literature, different methods are utilized
for the synthesis of N-arylsulfonamides via metal-
catalyzed cross-coupling of sulfonamides with either aryl
boronic acids or acids aryl halides (Scheme 4,

16 of 18
ALAVINIA ET AL.
FIGURE 14 FT-IR spectra and
SEM images of PEA-PSA@CuI after the
reaction
SCHEME 4 Various methods for
synthesis of N-arylsulfonamides
equation (1)). As shown in Table 6, palladium and copper
are applied as catalysts under different conditions. It is of
note that, in the current work, using PEA-PSA@CuI
along with the silver(I)/persulfate can remarkably
shorten the reaction time and enhance the product yield.
Despite the high efficiency of N-arylation of sulfonamides
with copper or palladium as a catalyst with either aryl
halides or aryl boronic acids,[43] traditional cross-
coupling techniques typically require highly toxic and
high-cost heavy transition metals, as well as preactivated
coupling partners such as aryl/alkyl halides or pseudo-
halides and moisture-sensitive organometallic reagents.
Therefore, these techniques often produce undesired,
toxic, and stoichiometric side-products.[44] Also, the prob-
lem with homogeneous catalysis is the prolonged reac-
tion time and difficulty involved in separating the
catalyst from the reaction mixture.[45] To deal with this
issue, the development of a recyclable and highly effi-
cient heterogeneous catalyst that would develop the envi-
ronmental effect of producing N-aryl sulfonamide is of
much interest and still in high demand. The catalyst is
composed of porous crosslinked polysulfonamides which
as a non-toxic and biological polymer makes the catalyst
more environmentally friendly. Also, as seen in Table 6,
TABLE 6 Comparison of the present methodology with other reported catalysts for the synthesis of
4-methyl-N-phenylbenzenesulfonamide 3a
Entry
Conditions
Yield (%) [Ref]
1
2
3
4
5
6
7
CuI(20 mol%), PhI, Ligand, K3PO4, DMF, N2, 100 ꢀC, 48 hr
CuI(10 mol%), PhBr, MW, K2CO3, Ligand, 195 ꢀC, 3 hr
CuI(20 mol%), PhI, Ligand KF/Al2O3, Dioxane, 100–110 ꢀC, 9 hr
CuI(5 mol%), PhI, Cs2CO3, DMF, Air, 130 ꢀC, 24 hr
CuCl(10 mol%), PhB (OH)2, MeOH, Air, 25 ꢀC, 1 hr
Pd (OAc)2(20 mol%), PhBr, PEG, TBAA, 35 ꢀC, 4 hr
95[46]
70[28]
93[46]
86[47]
95[43]
85[48]
PEA-PSA@CuI(3.5mol%), AgNO3(1 mol%), K2S2O8, PhCOOH, Toluene, 110 ꢀC,
1 hr
90, 88, 88, 88, 86, 84 [This work]

DECARBOXYLATIVE SYNTHESIS OF N-ARYLSULFONAMIDES
17 of 18
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the presence of crosslinked poly sulfonamides in the sup-
port matrix seems absolutely necessary for more chemical
stability of catalyst than other ones in the recycled forms
because after several runs, whatever the amount of
decomposition is less, the activity of the catalyst is surely
more. The most significant advantages of this work
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without using base, and using carboxylic acids or
inactivated arenes as arylating agents.
4 | CONCLUSIONS
In summary, a novel class of polysulfonamides was
synthesized using the template and functionalized
monomers and it was then utilized as a stabilizer for the
catalytically active CuI NPs. A variety of characteriza-
tions confirm that CuI NPs have been successfully grafted
on the polysulfonamide surface. The catalytic activity of
PEA-PSA@CuI along with silver(I)/persulfate was
explored in decarboxylative oxidative C-N coupling of
carboxylic acids with sulfonamides to afford N-
arylsulfonamides, as important materials in medicine
and biology. This protocol gave various advantages such
as excellent product yields, easy purification, simple pro-
cedure, and recyclability of the catalyst. It is expected that
the current study can provide the development basis of
porous polysulfonamides as tunable support for stabiliz-
ing catalytically active species. In conclusion, this article
offers a novel application for sulfonamides chemistry.
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ACKNOWLEDGEMENTS
The authors would like to thank Bu-Ali Sina University,
Center of Excellence Developmental of Environmentally
Friendly Methods for Chemical Synthesis (CEDEFMCS)
for financial supporting of this research.
ORCID
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Sedigheh Alavinia https://orcid.org/0000-0002-5421-
777X
Ramin Ghorbani-Vaghei https://orcid.org/0000-0001-
8322-6299
Jamshid Rakhtshah https://orcid.org/0000-0002-1421-
1007
Jaber Yousefi Seyf https://orcid.org/0000-0001-5624-
1127
Iman Ali Arabian https://orcid.org/0000-0002-1970-
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How to cite this article: Alavinia S, Ghorbani-
Vaghei R, Rakhtshah J, Yousefi Seyf J, Ali
Arabian I. Copper iodide nanoparticles-decorated
porous polysulfonamide gel: As effective catalyst
for decarboxylative synthesis of N-
Arylsulfonamides. Appl Organometal Chem. 2020;
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