Copper-catalyzed redox coupling of nitroarenes with sodium sulfinates

Article abstract of DOI:10.3390/molecules24071407

A simple copper-catalyzed redox coupling of sodium sulfinates and nitroarenes is described. In this process, abundant and stable nitroarenes serve as both the nitrogen sources and oxidants, and sodium sulfinates act as both reactants and reductants. A variety of aromatic sulfonamides were obtained in moderate to good yields with broad substrate scope. No external additive is employed for this kind of transformation.

Full text of DOI:10.3390/molecules24071407

molecules
Communication
Copper-Catalyzed Redox Coupling of Nitroarenes
with Sodium Sulfinates
Saiwen Liu 1,*, Ru Chen 2 and Jin Zhang 1,
*
1
College of Materials and Chemical Engineering, Hunan City University, Yiyang 413000, China
Yiyang Agriculture Products Quality Detect Center, Yiyang 413000, China; chenrudaxia@163.com
Correspondence: liusaiwen7@163.com (S.L.); tccdzdc@163.com (J.Z.)
2
*
ꢀꢁꢂꢀꢃꢄꢅꢆꢇ
Academic Editor: Derek J. McPhee
Received: 9 March 2019; Accepted: 4 April 2019; Published: 10 April 2019
ꢀꢁꢂꢃꢄꢅꢆ
Abstract: A simple copper-catalyzed redox coupling of sodium sulfinates and nitroarenes is described.
In this process, abundant and stable nitroarenes serve as both the nitrogen sources and oxidants,
and sodium sulfinates act as both reactants and reductants. A variety of aromatic sulfonamides were
obtained in moderate to good yields with broad substrate scope. No external additive is employed
for this kind of transformation.
Keywords: copper; redox; additive-free
1. Introduction
Nitroarenes are a class of the most readily available starting materials in synthetic organic
chemistry. The most important property of nitroarenes is able to undergo various reduction-based
reactions, especially for the preparation of primary aromatic amines. The traditional processes mainly
rely on using a stoichiometric amount of metal/acid or catalytic hydrogenation [
of nitroarenes to form new C-N bonds is highly attractive, and great effort has been made on the
subject during the past decades [ ]. However, external reducing reagents such as hydrogen and
transition-metals are necessary in most cases [10 13]. Recently, there has been significant interest in the
1–6]. Direct use
7–9
–
transition-metal-catalyzed C-N bond formation from nitroarenes by use of in situ borrowing-hydrogen
strategy [14–19]. Among these transformations, two types of reactions can be summarized according
to the resultant products: reductive cyclizations and reductive couplings. They provide convenient
access to amine, amide and N-heterocycles directly from aromatic nitro compounds [20–31].
N-arylsulfonamides are common building blocks among many pharmaceuticals and biologically
active molecules [32
The classical methods mainly use arylamines as the nitrogen sources reacting with sulfonyl chlorides
or sodium sulfinates [40 45]. Alternatively, N-arylsulfonamides have been successfully synthesized by
the transition-metal-catalyzed cross-coupling of sulfonamides with aryl halides, aryl boronic acids,
cyclohexanones, alcohols and hydrocarbons [46 57]. Nevertheless, they suffer from some drawbacks
–35]. Various efforts have been made for the synthesis of sulfonamides [36–39].
–
–
of low atom-, step-, and efficiency. In the case of genotoxic and unstable anilines, the undesired
impurities may be obtained during the conversion process. Recently, stable and abundant nitroarenes
have emerged as a highly attractive nitrogen source for the construction of N-arylsulfonamides. A series
of Fe-based coupling reaction of sodium arylsulfinates or arylsulfonyl chlorides with nitroarenes to
synthesize N-arylsulfonamides have developed. This kind of transformation required stoichiometric
amounts of NaHSO3 or Fe dust as the reductant [58
palladium-catalyzed method for the synthesis of N-arylsulfonamides from arylsulfonyl hydrazides
and nitroarenes without external reductants [62 63]. It would be highly desirable to develop a process
–61]. Notably, Deng and co-workers developed a
,
using inexpensive and non-toxic metal such as copper for the concise and facile preparation of
N-arylsulfonamides from nitroarenes. We hypothesized sodium sulfinate, which generally served
Molecules 2019, 24, 1407; doi:10.3390/molecules24071407
www.mdpi.com/journal/molecules

Molecules 2019, 24, 1407
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as reducing regent and was oxidized in the sulfonylation reactions, would be participated in the
reductive coupling reactions of nitroarenes. Herein, we present a copper-catalyzed reductive coupling
of nitroarenes using sodium sulfinate as the coupling partner and reducing regent, which gives rise to
an alternative access to pharmacologically significant N-aryl sulfonamides (Scheme 1).
Scheme 1. Copper-catalyzed redox coupling of nitroarenes with sodium sulfinates.
2. Results
2.1. Optimization of Reaction Conditions for Synthesis of 4-Methyl-N-(p-tolyl)benzenesulfonamide 3a
To begin our study, the reaction of commercially available p-methyl nitrobenzene (1a) and sodium
◦
4-methylbenzenesulfinate (2a) was chosen as the model under argon at 120 C to optimize the reaction
conditions. Three equivalents of sodium sulfinates were used because the substrate served as a
reductant. The product 3a was obtained in only 10% yield without any metal-catalyst (Table 1, entry 1).
The use of FeCl2
Copper catalyst was found crucial, and various copper salts were investigated for this transformation.
Similar results were obtained when employing CuCO3 Cu(OH)2, Cu(OTf)2, CuCl2, CuI as the catalyst
·
4H2O and FeSO4 7H2O afforded 3a in 20% and 11% yields, respectively (entries 2–3).
·
·
(entries 4–7). Among the various copper salts examined, CuCl was the most effective, and its use
resulted in the formation of 3a in 92% yield (entry 9). CuBr and Cu powder also promoted the reaction
with slightly lower efficiency (entries 8 and 10). The choice of solvents was important for this reaction.
The use of DMF and DMSO reduced the reaction yields to 78% and 75%, respectively (entries 11 and
12). Only a trace amount of products were obtained when reactions were carried out in weak polar
solvents such as anisole, dioxane, toluene and diglyme (entries 13–16). Unfortunately, a much lower
yield was acquired when the reaction was conducted under an atmosphere of air (entry 17).
Table 1. Optimization of the reaction conditions a.
Yield b (%)
Entry
Catalyst
Solvent
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
-
FeCl2·4H2O
FeSO4·7H2O
Cu2(OH)2CO3
Cu(OTf)2
CuCl2
NMP
NMP
NMP
NMP
NMP
NMP
NMP
NMP
NMP
10
20
11
31
45
30
46
82
92
86
78
75
0
CuI
CuBr
CuCl
Cu
CuCl
CuCl
CuCl
CuCl
NMP
DMF
DMSO
Anisole
Dioxane
Toluene
Diglyme
NMP
8
0
CuCl
CuCl
CuCl
15
52 c
a
Reaction conditions: 1a (0.2 mmol), 2a (0.6 mmol), CuCl (5 mol%), H2O (2 equiv.), solvent (0.6 mL), 120 ◦C, 40 h,
b
c
under argon. GC yield based on 1a. under air.

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2.2. Substrate Scope for the Nitroarenes
With the optimized conditions in hand, the scope of the reaction with respect to sodium
4-methylbenzenesulfinate (2a) and various nitroarenes was investigated (Table 2). The reaction
was found to be general, giving the desired N-aryl sulfonamides (3) in reasonable yields.
When nitrobenzene was used, the desired product 3b was achieved in 70% yield. Common functional
substituents such as methoxy and acetyl were compatible with the optimized conditions, and the
desired products 3c and 3d were obtained in 68% and 70% yields, respectively. Notably, active
functional groups such as ester were well tolerated, giving the target products in good yields
( , 3f). The substituent position on nitroarenes did not show obvious influence on the reaction
3e
yields. Moderate yields were obtained when o-methylnitrobenzene, m-methylnitrobenzene and
2,4-dimethylnitrobenzene were used (3g 3i). Nitroarenes possessing electron-withdrawing group
on the phenyl ring also reacted smoothly with 2a and afforded the desired product in good yield
3j).When naphthalenyl substrate 1k was used, the desired product 3k was obtained in 56% yield.
–
(
To our delight, hetero-nitroarenes such as 6-nitrobenzothiazole and 5-nitroindole also could react with
2a to give the corresponding sulfonamides in 60% and 42% yields, respectively (3l, 3m).
Table 2. Reaction of 2a with various nitroarenes a.
a
Conditions:
1
(0.2 mmol), 2a (0.6 mmol), CuCl (5 mol%), H2O (2 equiv.), NMP (0.6 mL), 120 ◦C, 40 h, under argon;
b
isolated yield. DMF as solvent.
2.3. Substrate Scope for the Sodium Sulfinates
To further examine the scope and the limitations of the reaction, various sodium sulfinates were
treated with p-methyl nitrobenzene under the standard conditions (Table 3). Sodium benzenesulfinate
reacted with 1a smoothly and gave the desired product 3n in 81% yield. Other substrates bearing
electron-donating group such as methoxy and tert-butyl remained effective and gave the corresponding
arylsulfonamides in 72% and 53% yields, respectively (3o, 3p). Functional groups halogens were well

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tolerated and afforded the desired products in moderate yields (entries 3q
–
3s). The reaction showed
poor activity when trifluoromethyl group were presented at the para position (3t). Gratifyingly, besides
aromatic sodium sulfinates, aliphatic sodium methanesulfinate could also react with 1a to give the
target products in 71% yield (3u).
Table 3. Reaction of 1a with various sodium sulfinates a.
a
Conditions: 1a (0.2 mmol),
Isolated yield.
2
(0.6 mmol), CuCl (5 mol%), H2O (2 equiv.), NMP (0.6 mL), 120 ◦C, 40 h, under argon.
b
2.4. Mechanism
To gather more information about the reaction mechanism, a series of control experiments were set
up under different reaction conditions (Scheme 2). When the radical scavenger 1,1-diphenylethylene or
2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) was added to the reaction, the desired product 3a was
obtained in 37% and 7% GC yields, respectively (Scheme 2a). This indicates that the present reaction
process perhaps wasn’t a free radical mechanism. Treatment of sodium 4-methylbenzenesulfinate
2a with 4-methyl nitrosobenzene or phenylhydroxylamine under the standard reaction conditions
afforded the corresponding product in 32% and 10% yield, respectively (Scheme 2b), which implies
both the two compounds were not involved as the key intermediate in this coupling reaction. Notably,
no product was detected when p-toluidine reacted with sodium sulfinate (Scheme 2c). This means that
sodium sulfinate could not directly reduce nitrobenzene into aniline in this catalytic system.
Scheme 2. Control experiments.

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While the exact mechanism of the reductive coupling of nitroarenes with sodium sulfinate is
not clear, as the previously reported nitrobenzene-based reduction [61 63], these mechanistically
experimental results encouraged us to propose an inner pathway of the redox process. As shown in
Scheme 3, this reaction starts from the coordination between sodium sulfinate and Cu(I) to form
copper(I) sulfinic acid salt . Then, complexation and nucleophilic addition of the lone electron pair of
the sulfur moiety to the nitro group of produce a five-membered metallocycle . Next, reduction
of by the second molecule of generates complex , followed by the liberation of a sulfonate to
afford intermediate . Subsequently, continues to be reduced by the third molecule of to copper
N-arylsulfonamide salt affords the desired product
–
2
A
1
B
B
2
C
D
D
2
E
along with the sulfonate. At last, protonation of E
and regenerates the Cu catalyst.
Scheme 3. Possible reaction mechanism.
3. Materials and Methods
3.1. General Information
All experiments were carried out under an atmosphere of argon. Flash column chromatography
1
was performed over silica gel 48–75
µ
m. H-NMR and 13C-NMR spectra were recorded on Bruker-AV
(400 and 100 MHz, respectively) instrument (Billerica, MA, USA) internally referenced to SiMe4
or chloroform signals. MS analyses were performed on Agilent 5975 GC-MS instrument (EI)
(
Santa Clara, CA, USA). The structure of known compounds were further corroborated by comparing
their 1H-NMR, 13C-NMR data and MS data with those of literature. All reagents were used as received
from commercial sources without further purification. All nitroarenes and sulfinic acid sodium salts
2a, 2b, 2g 2h, and 2j employed were reagent grade materials, and others were prepared according to
the literature procedures.
3.2. General Procedure for the Preparation of Sodium Sulfinates
4-Methoxybenzenesulfinic acid sodium salt (2e) was prepared by heating 2.5 g of sodium sulfite,
2.06 g of 4-methoxybenzenesulphonyl chloride, and 1.68 g of sodium bicarbonate in 9.6 mL of water
at 70–80 ◦C for 4 h. After cooling to room temperature, water was removed under vacuum and the
residue was extracted by ethanol, recrystallization as a white solid, the yield was 67% (1.34 g). Similarly,
other sodium arenesulfinates were prepared from their corresponding sulfonyl chlorides.

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3.3. General Procedure for the Synthesis of N-Arylsulfonamides
A pressure tube (10 mL) was charged with CuCl (1.0 mg, 0.01 mmol), p-toluenesulfinic acid
sodium salt (2a, 107.2 mg, 0.6 mmol), p-methyl nitrobenzene (1a, 27.4 mg, 0.2 mmol) and purged with
argon three times. NMP (0.6 mL) and H2O (7.2
stirred at 120 ◦C for 40 h. After cooling to room temperature, the crude product mixture was diluted
with ethylacetate (15 mL) and washed with a saturated solution of NaCl (3 15 mL) and the organic
µL) were added by syringe. The resulting solution was
×
layer was dried over MgSO4 and concentrated under reduced pressure. The resulting residue was
purified by column chromatography (silica gel, petroleum ether/ethyl acetate = 6:1) to give 3a as white
solid; yield: 40.3 mg (77%) (NMR spectra for all compounds shown in Supplementary Materials).
3.4. Product Characterization
4-Methyl-N-p-tolylbenzenesulfonamide (3a) [58]: White solid, 77% yield (40.3 mg), 1H-NMR (400 MHz,
CDCl3, ppm)
δ
7.64 (d, J = 8.4 Hz, 2H), 7.24 n, 2H), 7.05 (d, J = 8.0 Hz, 2H), 6.96 (d, J = 8.0 Hz, 2H),
143.7, 136.2, 135.3, 133.9,
6.51 (s, 1H), 2.40 (s, 3H), 2.29 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ
129.8, 129.6, 127.3, 122.2, 21.5, 20.8; MS (EI) m/z (%) 261, 155, 106 (100), 91, 77, 65.
4-Methyl-N-phenyl-benzenesulfonamide (3b) [58]: White solid, 70% yield (34.6 mg), 1H-NMR (400 MHz,
CDCl3, ppm)
2H), 6.55 (s, 1H), 2.37 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
125.2, 121.5, 21.5; MS (EI) m/z (%) 247, 182, 168, 155, 91 (100), 65.
δ
7.64 (d, J = 7.6 Hz, 2H), 7.26–7.22 (m, 4H), 7.11 (t, J = 7.2 Hz, 1H), 7.05 (d, J = 7.4 Hz,
δ
143.9, 136.7, 136.2, 129.7, 129.3, 127.3,
4-Methyl-N-(4-methoxyphenyl)-benzenesulfonamide (3c) [58]: White solid, 68% yield (37.7 mg), 1H-NMR
(400 MHz, CDCl3, ppm)
δ 7.58 (d, J = 7.8 Hz, 2H), 7.24 (d, J = 7.5 Hz, 2H), 6.98 (d, J = 8.6 Hz, 2H),
6.78 (d, J = 8.2 Hz, 2H), 6.20 (s, 1H), 3.78 (s, 3H), 2.41 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
143.7, 136.1, 129.6, 129.1, 127.4, 125.3, 114.5, 55.4, 21.5; MS (EI) m/z (%) 277, 122 (100), 95, 65.
δ 157.9,
4-Methyl-N-p-acetylphenyl-benzenesulfonamide (3d) [55]: Off-white solid, 70% yield (44.0 mg), 1H-NMR
(400 MHz, CDCl3, ppm) 7.85 (d, J = 8.0 Hz, 2H), 7.32 (d, J = 7.4 Hz, 2H), 7.26 (s, 2H), 7.14 (d, J = 7.7 Hz
2H), 6.88 (s, 1H), 2.53 (s, 3H), 2.38 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
196.6, 144.4, 141.0, 135.9,
133.4, 129.9, 129.8, 127.2, 119.1, 26.3, 21.5; MS (EI) m/z (%) 289, 274, 155, 106, 91 (100), 77, 65.
δ
,
δ
Methyl-4-(4-methylphenylsulfonamido) benzoate (3e) [58]: Off-white solid, 76% yield (46.4 mg), 1H-NMR
(400 MHz, CDCl3, ppm) 7.94 (d, J = 7.8 Hz, 2H), 7.72 (d, J = 7.6 Hz, 2H), 7.28 (s, 2H), 7.13 (d, J = 7.8 Hz
2H), 6.77 (s, 1H), 3.89 (s, 3H), 2.40 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
166.3, 144.4, 140.9, 132.6,
131.1, 129.8, 127.3, 126.4, 119.2, 52.1, 21.5; MS (EI) m/z (%) 305, 155, 122, 91 (100), 65.
δ
,
δ
Ethyl-4-(4-methylphenylsulfonamido) benzoate (3f) [55]: Off-white solid, 78% yield (49.8 mg), 1H-NMR
(400 MHz, CDCl3, ppm) 7.94 (s, 2H), 7.72 (s, 2H), 7.28 (s, 2H), 7.13 (s, 2H), 6.79 (s, 1H), 4.35 (s, 2H),
2.40 (s, 3H), 1.38 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
165.9, 144.4, 140.8, 135.9, 131.1, 129.8,
δ
δ
127.3, 126.8, 119.2, 61.0, 21.5, 14.3; MS (EI) m/z (%) 319, 274, 155, 119, 108, 91 (100), 65.
4-Methyl-N-o-tolyl-benzenesulfonamide (3g) [58]: White solid, 55% yield (28.7 mg), 1H-NMR (400 MHz,
CDCl3, ppm)
δ
7.60 (d, J = 7.7 Hz, 2H), 7.31 (d, J = 7.8 Hz, 1H), 7.21 (d, J = 7.6 Hz, 2H), 7.14 (s, 1H),
143.8, 136.9,
7.08 (s, 2H), 6.23 (s, 1H), 2.39 (s, 3H), 1.99 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ
134.6, 131.5, 130.8, 129.6, 127.6, 126.9, 126.2, 124.4, 21.5, 17.6; MS (EI) m/z (%) 261, 155, 106 (100), 91,
77, 65.
4-Methyl-N-m-tolyl-benzenesulfonamide (3h) [58]: White solid, 68% yield (35.5 mg) 1H-NMR (400 MHz,
CDCl3, ppm)
1H), 6.88 (s, 1H), 6.83 (d, J = 7.5 Hz, 1H), 6.42 (s, 1H), 2.38 (s, 3H), 2.27 (s, 3H); 13C-NMR (100 MHz,
CDCl3, ppm) 143.8, 139.3, 136.7, 136.3, 129.6, 129.1, 127.3, 125.9, 122.0, 118.3, 21.5, 21.3; MS (EI) m/z
(%) 261, 196, 182, 155, 106 (100), 91, 77, 65.
δ 7.64 (d, J = 7.8 Hz, 2H), 7.22 (d, J = 7.6 Hz, 2H), 7.10 (t, J = 7.5 Hz, 1H), 6.92 (d, J = 7.3 Hz,
δ

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4-Methyl-N-(2,4-dimethylphenyl)-benzenesulfonamide (3i) [64]: White solid, 64% yield (35.2 mg), 1H-NMR
(400 MHz, CDCl3, ppm) 7.61 (d, J = 7.6 Hz, 2H), 7.24 (d, J = 7.5 Hz, 2H), 7.15 (d, J = 7.8 Hz, 1H), 6.95 (d,
J = 7.9 Hz, 1H), 6.92 (s, 1H), 6.18 (s, 1H), 2.41 (s, 3H), 2.28 (s, 3H), 1.96 (s, 3H); 13C-NMR (100 MHz,
CDCl3, ppm) 143.6, 137.0, 136.2, 132.3, 131.8, 131.5, 129.6, 127.4, 127.2, 125.3, 21.5, 20.9, 17.6; MS (EI)
m/z (%) 275, 120 (100), 91, 77.
δ
δ
1
4-Methyl-N-m-cyanophenyl-benzenesulfonamide (3j) [62]: White solid, 75% yield (40.8 mg), H-NMR
(400 MHz, CDCl3, ppm) 7.69 (d, J = 6.6 Hz, 2H), 7.38–7.35 (m, 3H), 7.29–7.27 (m, 2H), 7.06 (s, 1H),
2.41 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
144.7, 137.8, 135.6, 130.3, 130.0, 128.5, 127.2, 125.1,
δ
δ
123.6, 118.0, 113.4, 21.6; MS (EI) m/z (%) 272, 155, 91 (100), 65.
4-Methyl-N-(naphthalene-1-yl)benzenesulfonamide (3k) [62]: White solid, 56% yield (33.3 mg), 1H-NMR
(400 MHz, CDCl3, ppm)
δ
7.81 (d, J = 5.4 Hz, 2H), 7.72 (s, 1H), 7.62 (d, J = 6.4 Hz, 2H), 7.45 (s, 2H),
143.8,
7.37 (s, 2H), 7.16 (d, J = 6.2 Hz, 2H), 6.79 (s, 1H), 2.34 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ
136.5, 134.3, 131.5, 129.6, 128.9, 128.4, 127.4, 127.2, 126.6, 126.3, 125.4, 122.7, 121.5, 21.5; MS (EI) m/z (%)
297, 142 (100), 115, 91.
N-(Benzo[d]thiazol-6-yl)-4-methylbenzenesulfonamide (3l) [65]: Off-white solid, 60% yield (36.5 mg),
1H-NMR (400 MHz, CDCl3, ppm)
δ
8.96 (s, 1H), 7.98 (d, J = 8.4 Hz, 1H), 7.84 (s, 1H), 7.67 (d, J = 7.3 Hz
2H), 7.24 (d, J = 7.2 Hz, 2H), 7.15 (d, J = 8.4 Hz, 1H), 7.03 (s, 1H), 2.39 (s, 3H); 13C-NMR (100 MHz,
CDCl3, ppm) 154.0, 150.8, 144.1, 136.0, 134.8, 134.6, 129.8, 127.3, 124.0, 121.0, 114.6, 21.5; MS (EI) m/z
,
δ
(%) 304, 149 (100), 122, 105, 91, 65.
N-(1H-Indol-5-yl)-4-methylbenzenesulfonamide (3m): White solid, 42% yield (24.0 mg), 1H-NMR
(400 MHz, CDCl3, ppm)
δ 8.18 (s, 1H), 7.59 (d, J = 7.3 Hz, 2H), 7.34 (s, 2H), 7.24 (s, 1H), 7.20 (d,
J = 7.1 Hz, 2H), 6.90 (d, J = 8.3 Hz, 1H), 6.49 (s, 1H), 6.31 (s, 1H), 2.38 (s, 3H); 13C-NMR (100 MHz,
CDCl3, ppm)
δ 143.4, 136.4, 134.3, 129.4, 128.5, 127.4, 126.3, 125.3, 119.5, 116.7, 111.4, 103.0, 21.5; MS (EI)
m/z (%) 286, 131 (100), 104, 91, 77; HRMS calcd. for C15H15N2O2S [M + H]+ 287.0784, found 287.0779.
N-(4-Methylphenyl)-benzenesulfonamide (3n) [58]: White solid, 81% yield (40.0 mg), 1H-NMR (400 MHz,
CDCl3, ppm)
δ 7.74 (d, J = 7.6 Hz, 2H), 7.54 (t, J = 7.2 Hz, 1H), 7.44 (t, J = 7.5 Hz, 2H), 7.05 (d, J = 7.9 Hz,
2H), 6.94 (d, J = 7.9 Hz, 2H), 6.39 (s, 1H), 2.28 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
133.7, 132.9, 129.9, 129.0, 127.3, 122.5, 20.8; MS (EI) m/z (%) 247, 106 (100), 77, 51.
δ 139.2, 135.5,
4-Methoxy-N-p-tolylbenzenesulfonamide (3o) [55]: White solid, 72% yield (39.9 mg), 1H-NMR (400 MHz,
CDCl3, ppm) δ 7.69 (d, J = 8.5 Hz, 2H), 7.05 (d, J = 7.6 Hz, 2H), 6.96 (d, J = 7.6 Hz, 2H), 6.90 (d, J = 8.4 Hz,
2H), 6.54 (s, 1H), 3.85 (s, 3H), 2.29 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ 163.1, 135.3, 133.9, 130.8,
129.8, 129.5, 122.3, 114.2, 55.6, 20.9; MS (EI) m/z (%) 277, 171, 106 (100), 77.
4-Tert-butyl-N-p-tolylbenzenesulfonamide (3p) [66]: White solid, yield: 32.1 mg (53%), 1H-NMR (400 MHz,
CDCl3, ppm) 7.68 (d, J = 7.5 Hz, 2H), 7.45 (d, J = 7.4 Hz, 2H), 7.07 (d, J = 7.0 Hz, 2H), 6.98 (d, J = 6.8 Hz
2H), 6.39 (s, 1H), 2.30 (s, 3H), 1.32 (s, 9H); 13C-NMR (100 MHz, CDCl3, ppm)
156.7, 136.3, 135.1, 134.0,
129.8, 127.1, 126.0, 122.0, 35.1, 31.1, 20.8; MS (EI) m/z (%) 303, 182, 133, 106 (100), 77.
δ
,
δ
4-Fluoro-N-p-tolylbenzenesulfonamide (3q) [67]: White solid, 50% yield (26.5 mg), 1H-NMR (400 MHz,
CDCl3, ppm) 7.75 (t, J = 5.9 Hz, 2H), 7.12 (t, J = 8.5 Hz, 2H), 7.08 (d, J = 7.9 Hz, 2H), 6.95 (d, J = 7.8 Hz,
2H), 6.36 (s, 1H), 2.31 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
165.2 (d, J = 253 Hz), 135.9, 135.1 (d,
δ
δ
J = 3.0 Hz), 133.4, 130.1 (d, J = 9.4 Hz), 130.0, 122.7, 116.2 (d, J = 22.5 Hz), 20.8; MS (EI) m/z (%) 265,
106 (100), 95, 77.
4-Chloro-N-p-tolylbenzenesulfonamide (3r) [59]: Off-white solid, 59% yield (33.3 mg), 1H-NMR (400 MHz,
CDCl3, ppm) δ 7.67 (d, J = 7.6 Hz, 2H), 7.42 (d, J = 7.5 Hz, 2H), 7.08 (d, J = 6.7 Hz, 2H), 6.95 (d, J = 6.7 Hz,
2H), 6.45 (s, 1H), 2.31 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ 139.5, 139.4, 136.2, 133.2, 130.0, 129.3,
128.7, 122.9, 20.9; MS (EI) m/z (%) 281, 106 (100), 77.

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4-Bromo-N-p-tolylbenzenesulfonamide (3s) [68]: Off-white solid, 63% yield (41.0 mg), 1H-NMR (400 MHz,
CDCl3, ppm) δ 7.59 (s, 4H), 7.08 (d, J = 7.3 Hz, 2H), 6.95 (d, J = 7.0 Hz, 2H), 6.37 (s, 1H), 2.31 (s, 3H);
13C-NMR (100 MHz, CDCl3, ppm)
δ
138.2, 136.1, 133.2, 132.3, 130.1, 128.8, 128.0, 122.9, 20.9; MS (EI)
m/z (%) 327, 106 (100), 77.
1
4-Trifluoromethyl-N-p-tolylbenzenesulfonamide (3t) [55]: White solid, yield: 25.3 mg (40%), H-NMR
(400 MHz, CDCl3, ppm)
δ
7.87 (d, J = 7.1 Hz, 2H), 7.72 (d, J = 7.1 Hz, 2H), 7.09 (d, J = 6.8 Hz, 2H),
142.7, 136.4,
6.97 (d, J = 6.7 Hz, 2H), 6.63 (s, 1H), 2.31 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ
134.6 (q, J = 33 Hz), 132.9, 130.1, 127.8, 126.1 (q, J = 3.7 Hz), 123.2 (q, J = 271.1 Hz), 123.0, 20.8; MS (EI)
m/z (%) 315, 145, 106 (100), 77.
N-p-Tolymethanesulfonamide (3u) [55]: Off-white solid, 71% yield (26.3 mg), 1H-NMR (400 MHz, CDCl3,
ppm)
δ
7.16 (d, J = 7.2 Hz, 4H), 6.46 (s, 1H), 3.00 (s, 3H), 2.36 (s, 3H); 13C-NMR (100 MHz, CDCl3, ppm)
δ 135.6, 134.1, 130.2, 121.7, 39.0, 20.8; MS (EI) m/z (%) 185, 106 (100), 79.
4. Conclusions
In summary, we have developed a simple synthetic method for the preparation of
N-arylsulfonamides via copper-catalyzed redox coupling of sodium sulfinates and nitroarenes.
Aromatic sulfonamides were formed in moderate to good yields in the absence of external oxidant or
reductant. Active functional groups such as ester, cyano, and halogens were well tolerated under the
optimized conditions. This method affords an alternative route for the synthesis of N-aryl sulfonamides
under mild conditions. Moreover, this protocol would inspire other cases of nitroarene reduction-based
synthesis of complex compounds. The detailed mechanism and the synthetic applications of this
reaction are currently under investigation.
Supplementary Materials: The supplementary materials are available online.
Author Contributions: Conceptualization, S.L. and J.Z.; methodology, R.C.; writing—original draft preparation,
S.L.; writing—review and editing, S.L.
Funding: We gratefully thank the Normal Project Foundation of Hunan Provincial Education Department
(18C0845) and the Key Project Foundation of Hunan Provincial Education Department (18A396).
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
2.
3.
Kerr, J.M.; Suckling, C.J.; Bamfield, P. Selective Hydrogenation by A Novel Palladium(II) Complex.
Tetrahedron Lett. 1988, 29, 5545–5548. [CrossRef]
Zhao, F.Y.; Zhang, R.; Chatterjee, M.; Ikushima, Y.; Arai, M. Hydrogenation of Nitrobenzene with Supported
Transition Metal Catalysts in Supercritical Carbon Dioxide. Adv. Synth. Catal. 2004, 346, 661–668. [CrossRef]
Corma, A.; Serna, P.; Concepcion, P.; Calvino, J.J. Transforming Nonselective into Chemoselective Metal
Catalysts for the Hydrogenation of Substituted Nitroaromatics. J. Am. Chem. Soc. 2008, 130, 8748–8753.
[CrossRef]
4.
5.
6.
Cantillo, D.; Baghbanzadeh, M.; Kappe, C.O. In Situ Generated Iron Oxide Nanocrystals as Efficient and
Selective Catalysts for the Reduction of Nitroarenes using a Continuous Flow Method. Angew. Chem. Int. Ed.
2012, 51, 10190–10193. [CrossRef]
Jagadeesh, R.V.; Surkus, A.E.; Junge, H.; Pohl, M.M.; Radnik, J.; Rabeah, J.; Huan, H.; Schünemann, V.;
Brückner, A.; Beller, M. Nanoscale Fe2O3-Based Catalysts for Selective Hydrogenation of Nitroarenes to
Anilines. Science 2013, 342, 1073–1076. [CrossRef] [PubMed]
Zhao, Z.K.; Yang, H.L.; Li, Y.; Guo, X.W. Cobalt-Modified Molybdenum Carbide as an Efficient Catalyst for
Chemoselective Reduction of Aromatic Nitro Compounds. Green Chem. 2014, 16, 1274–1281. [CrossRef]
Ono, N. The Nitro Group in Organic Synthesis; Wiley-VCH: New York, NY, USA, 2001.
Lawrence, S. Amines: Synthesis, Properties and Applications; Cambridge University Press: Cambridge, UK, 2004.
Arnold, H.; Döbert, F.; Gaube, J. In Handbook of Heterogeneous Catalysis; Wiley-Interscience: New York, NY, USA,
2008; pp. 3266–3284.
7.
8.
9.

Molecules 2019, 24, 1407
9 of 11
10. Srivastava, R.S.; Nicholas, K.M. Iron-Catalyzed Allylic Amination by Nitroorganics. Chem. Comm. 1998
24, 2705–2706. [CrossRef]
,
11. Chen, J.Z.; Ling, G.; Lu, S.W. Synthesis of N-Phenyl-N’-pyrimidylurea Derivatives by Selenium- or Selenium
Dioxide-Catalyzed Reductive Carbonylation of Nitroaromatics. Eur. J. Org. Chem. 2003, 17, 3446–3452.
[CrossRef]
12. Li, M.; Hu, L.Q.; Cao, X.H.; Hong, Y.; Lu, J.M.; Gu, H.W. Direct Hydrogenation of Nitroaromatics and
One-Pot Amidation with Carboxylic Acids over Platinum Nanowires. Chem. Eur. J. 2011, 17, 2763–2768.
[CrossRef] [PubMed]
13. Gui, J.; Pan, C.; Jing, Y.; Qin, T.; Lo, J.; Lee, B.; Spergel, S.; Mertzman, M.; Pitts, W.; Cruz, T.; et al. Practical
Olefin Hydroamination with Nitroarenes. Science 2015, 348, 886–891. [CrossRef]
14. Oakdale, J.; Solano, D.; Fettinger, J.; Haddadin, M.; Kurth, M.J. An Oxazolo[3,2-b]indazole Route to
1H-Indazolones. Org. Lett. 2009, 11, 2760–2763. [CrossRef]
15. Cui, X.J.; Zhang, Y.; Shi, F.; Deng, Y.Q. Ruthenium-Catalyzed Nitro and Nitrile Compounds Coupling with
Alcohols: Alternative Route for N-Substituted Amine Synthesis. Chem. Eur. J. 2011, 17, 2587–2591. [CrossRef]
16. Zanardi, A.; Mata, J.A.; Peris, E. One-Pot Preparation of Imines from Nitroarenes by a Tandem Process with
an Ir-Pd Heterodimetallic Catalyst. Chem. Eur. J. 2010, 16, 10502–10506. [CrossRef]
17. Tang, C.H.; He, L.; Liu, Y.M.; Cao, Y.; He, H.Y.; Fan, K.N. Direct One-Pot Reductive N-Alkylation of
Nitroarenes by using Alcohols with Supported Gold Catalysts. Chem. Eur. J. 2011, 17, 7172–7177. [CrossRef]
18. Nguyen, T.B.; Ermolenko, L.; Al-Mourabit, A. Iron Sulfide Catalyzed Redox/Condensation Cascade
Reaction between 2-Amino/Hydroxy Nitrobenzenes and Activated Methyl Groups: A Straightforward
Atom Economical Approach to 2-Hetaryl-benzimidazoles and -benzoxazoles. J. Am. Chem. Soc. 2013
135, 118–121. [CrossRef]
,
19. Cui, X.J.; Deng, Y.Q.; Shi, F. Reductive N-Alkylation of Nitro Compounds to N-Alkyl and N,N-Dialkyl
Amines with Glycerol as the Hydrogen Source. ACS Catal. 2013, 3, 808–811. [CrossRef]
20. Feng, C.; Liu, Y.; Peng, S.M.; Shuai, Q.; Deng, G.J.; Li, C.J. Ruthenium-Catalyzed Tertiary Amine Formation
from Nitroarenes and Alcohols. Org. Lett. 2010, 12, 4888–4891. [CrossRef]
21. Liu, Y.; Chen, W.; Feng, C.; Deng, G.J. Ruthenium-Catalyzed One-Pot Aromatic Secondary Amine Formation
from Nitroarenes and Alcohols. Chem. Asian J. 2011, 6, 1142–1146. [CrossRef]
22. Cano, R.; Ramón, D.J.; Yus, M. Impregnated Ruthenium on Magnetite as a Recyclable Catalyst for the
N-Alkylation of Amines, Sulfonamides, Sulfinamides, and Nitroarenes Using Alcohols as Electrophiles by a
Hydrogen Autotransfer Process. J. Org. Chem. 2011, 76, 5547–5557. [CrossRef]
23. Xiao, F.H.; Liu, Y.; Tang, C.L.; Deng, G.J. Peroxide-Mediated Transition-Metal-Free Direct Amidation of
Alcohols with Nitroarenes. Org. Lett. 2012, 14, 984–987. [CrossRef]
24. Wu, M.Y.; Hu, X.; Liu, J.; Liao, Y.F.; Deng, G.J. Iron-Catalyzed 2-Arylbenzoxazole Formation from
o-Nitrophenols and Benzylic Alcohols. Org. Lett. 2012, 14, 2722–2725. [CrossRef]
25. Wang, H.M.; Cao, X.X.; Xiao, F.H.; Liu, S.W.; Deng, G.J. Iron-Catalyzed One-Pot 2,3-Diarylquinazolinone
Formation from 2-Nitrobenzamides and Alcohols. Org. Lett. 2013, 15, 4900–4903. [CrossRef]
26. Wang, H.M.; Chen, H.; Chen, Y.; Deng, G.J. Palladium-Catalyzed One Pot 2-Arylquinazoline Formation via
Hydrogen-Transfer Strategy. Org. Biomol. Chem. 2014, 12, 7792–7799. [CrossRef]
27. Nguyen, T.B.; Ermolenko, L.; Al-Mourabit, A. Nitro-Methyl Redox Coupling: Efficient Approach to
2-Hetarylbenzothiazoles from 2-Halonitroarene, Methylhetarene, and Elemental Sulfur. Org. Lett. 2013
15, 4218–4221. [CrossRef]
,
28. Nguyen, T.B.; Retailleau, P.; Al-Mourabit, A. A Simple and Straightforward Approach to Quinoxalines
by Iron/Sulfur-Catalyzed Redox Condensation of o-Nitroanilines and Phenethylamines. Org. Lett. 2013
15, 5238–5241. [CrossRef]
,
29. Nguyen, T.B.; Bescont, J.L.; Ermolenko, L.; Al-Mourabit, A. Cobalt- and Iron-Catalyzed Redox
Condensation of o-Substituted Nitrobenzenes with Alkylamines: A Step- and Redox-Economical Synthesis
of Diazaheterocycles. Org. Lett. 2013, 15, 6218–6221. [CrossRef]
30. Nguyen, T.B.; Pasturaud, K.; Ermolenko, L.; Al-Mourabit, A. Concise Access to 2-Aroylbenzothiazoles
by Redox Condensation Reaction between o-Halonitrobenzenes, Acetophenones, and Elemental Sulfur.
Org. Lett. 2015, 17, 2562–2565. [CrossRef]

Molecules 2019, 24, 1407
10 of 11
31. Xing, Q.Y.; Ma, Y.F.; Xie, H.; Xiao, F.H.; Zhang, F.; Deng, G.J. Iron-Promoted Three-Component 2-Substituted
Benzothiazole Formation via Nitroarene ortho C-H Sulfuration with Elemental Sulfur. J. Org. Chem. 2019
84, 1238–1246. [CrossRef]
,
32. Ganguly, A.K.; Alluri, S.S.; Caroccia, D.; Biswas, D.; Wang, C.H.; Kang, E.; Zhang, Y.; McPhail, A.T.;
Carroll, S.S.; Burlein, C.; et al. Design, Synthesis, and X-ray Crystallographic Analysis of a Novel Class of
HIV-1 Protease Inhibitors. J. Med. Chem. 2011, 54, 7176–7183. [CrossRef]
33. Gilbert, A.M.; Caltabiano, S.; Koehn, F.E.; Chen, Z.-J.; Francisco, G.D.; Ellingboe, J.W.; Kharode, Y.;
Mangine, A.; Francis, R.; TrailSmith, M.; et al. Pyrazolopyrimidine-2,4-dione Sulfonamides: Novel and
Selective Calcitonin Inducers. J. Med. Chem. 2002, 45, 2342–2345. [CrossRef]
34. Masereel, B.; Rolin, S.; Abbate, F.; Scozzafava, A.; Supuran, C.T. Carbonic Anhydrase Inhibitors:
Anticonvulsant Sulfonamides Incorporating Valproyl and Other Lipophilic Moieties. J. Med. Chem. 2002
45, 312–320. [CrossRef]
,
35. Drew, J. Drug Discovery: A Historical Perspective. Science 2000, 287, 1960–1964. [CrossRef]
36. Wilden, J.; Geldeard, L.; Lee, C.; Judd, D.; Caddick, S. Trichlorophenol (TCP) Sulfonate Esters: A Selective
Alternative to Pentafluorophenol (PFP) Esters and Sulfonyl Chlorides for The Preparation of Sulfonamides.
Chem. Commun. 2007, 10, 1074–1076. [CrossRef]
37. Bahrami, K.; Khodaei, M.; Soheilizad, M. Direct Conversion of Thiols to Sulfonyl Chlorides and Sulfonamides.
J. Org. Chem. 2009, 74, 9287–9291. [CrossRef]
38. Zhu, M.; Wei, W.; Yang, D.; Cui, H.; Wang, L.; Meng, G.; Wang, H. Metal-Free I2O5-Mediated Direct
Construction of Sulfonamides from Thiols and Amines. Org. Biomol. Chem. 2017, 15, 4789–4793. [CrossRef]
39. Sheykhan, M.; Khani, S.; Abbasnia, M.; Shaabanzadeh, S.; Joafshan, M. An Approach to C–N Activation:
Coupling of Arenesulfonyl Hydrazides and Arenesulfonyl Chlorides with Tert-Amines via A Metal-, Oxidant-
and Halogen-free Anodic Oxidation. Green Chem. 2017, 19, 5940–5948. [CrossRef]
40. DeBergh, J.R.; Niljianskul, N.; Buchwald, S.L. Synthesis of Aryl Sulfonamides via Palladium-Catalyzed
Chlorosulfonylation of Arylboronic Acids. J. Am. Chem. Soc. 2013, 135, 10638–10641. [CrossRef]
41. Tang, X.; Huang, L.; Qi, C.; Wu, X.; Wu, W.; Jiang, H. Copper-Catalyzed Sulfonamides Formation from
Sodium Sulfinates and Amines. Chem. Commun. 2013, 49, 6102–6104. [CrossRef]
42. Buathongjan, C.; Beukeaw, D.; Yotphan, S. Iodine-Catalyzed Oxidative Amination of Sodium Sulfinates:
A Convenient Approach to the Synthesis of Sulfonamides under Mild Conditions. Eur. J. Org. Chem. 2015
7, 1575–1582. [CrossRef]
,
43. Pan, X.; Gao, J.; Liu, J.; Lai, J.; Jiang, H.; Yuan, G. Synthesis of Sulfonamides via I2-Mediated Reaction of Sodium
Sulfinates with Amines in An Aqueous Medium at Room Temperature. Green. Chem. 2015, 17, 1400–1403.
[CrossRef]
44. Yang, K.; Ke, M.; Lin, Y.; Song, Q. Sulfonamide Formation from Sodium Sulfinates and Amines or Ammonia
under Metal-free Conditions at Ambient Temperature. Green Chem. 2015, 17, 1395–1399. [CrossRef]
45. Sarkar, D.; Ghosh, M.K.; Rout, N. PTAB Mediated Open Air Synthesis of Sulfonamides, Thiosulfonates and
Symmetrical Disulfanes. Tetrahedron Lett. 2018, 59, 2360–2364. [CrossRef]
46. Baffoe, J.; Hoe, M.; Touré, B. Copper-Mediated N-Heteroarylation of Primary Sulfonamides: Synthesis of
Mono-N-heteroaryl Sulfonamides. Org. Lett. 2010, 12, 1532–1535. [CrossRef]
47. Burton, G.; Cao, P.; Li, G.; Rivero, R. Palladium-Catalyzed Intermolecular Coupling of Aryl Chlorides and
Sulfonamides under Microwave Irradiation. Org. Lett. 2003, 5, 4373–4376. [CrossRef]
48. Rosen, B.R.; Ruble, J.C.; Beauchamp, T.J.; Navarro, A. Mild Pd-Catalyzed N-Arylation of
Methanesulfonamide and Related Nucleophiles: Avoiding Potentially Genotoxic Reagents and Byproducts.
Org. Lett. 2011, 13, 2564–2567. [CrossRef]
49. Nasrollahzadeh, M.; Ehsani, A.; Maham, M. Copper-Catalyzed N-Arylation of Sulfonamides with Boronic
Acids in Water under Ligand-Free and Aerobic Conditions. Synlett 2014, 25, 505–508. [CrossRef]
50. Nasrollahzadeha, M.; Rostami-Vartooni, A.; Ehsani, A.; Moghadam, M. Fabrication, Characterization and
Application of Nanopolymer Supported Copper (II) Complex as an Effective and Reusable Catalyst for
the C-N Bond Cross-Coupling Reaction of Sulfonamides with Arylboronic Acids in Water under Aerobic
Conditions. J. Mol. Catal. A: Chem. 2014, 387, 123–129. [CrossRef]
51. Cao, X.; Bai, Y.; Xie, Y.; Deng, G.J. Palladium-Catalyzed Arylation of Aryl Sulfonamides with Cyclohexanones.
J. Mol. Catal. A: Chem. 2014, 383, 94–100. [CrossRef]

Molecules 2019, 24, 1407
11 of 11
52. Qu, P.; Sun, C.; Ma, J.; Li, F. The N-Alkylation of Sulfonamides with Alcohols in Water Catalyzed by the
Water-Soluble Iridium Complex {Cp*Ir[6,6 (OH)2bpy](H2O)}[OTf]2. Adv. Synth. Catal. 2014, 356, 447–459.
[CrossRef]
53. Ramachandran, R.; Prakash, G.; Selvamurugan, S.; Viswanathamurthi, P.; Malecki, J.G.; Ramkumar, V.
Efficient and Aersatile Catalysis of N-alkylation of Heterocyclic Amines with Alcohols and One-Pot
Synthesis of 2-Aryl Substituted Benzazoles with Newly Designed Ruthenium(II) Complexes of PNS
Thiosemicarbazones. Dalton Trans. 2014, 43, 7889–7902. [CrossRef]
54. Li, Q.Q.; Xiao, Z.F.; Yao, C.Z.; Zheng, H.X.; Kang, Y.B. Direct Alkylation of Amines with Alcohols Catalyzed
by Base. Org. Lett. 2015, 17, 5328–5331. [CrossRef]
55. Shekhar, S.; Dunn, T.B.; Kotechi, B.; Montavon, D.; Cullen, S.C. A General Method for Palladium-Catalyzed
Reactions of Primary Sulfonamides with Aryl Nonaflates. J. Org. Chem. 2011, 76, 4552–4563. [CrossRef]
56. Xiao, B.; Gong, T.J.; Xu, J.; Liu, Z.J.; Liu, L. Palladium-Catalyzed Intermolecular Directed C H Amidation of
−
Aromatic Ketones. J. Am. Chem. Soc. 2011, 133, 1466–1474. [CrossRef]
57. Zhao, H.Q.; Shang, Y.P.; Su, W.P. Rhodium(III)-Catalyzed Intermolecular N-Chelator-Directed Aromatic C-H
Amidation with Amides. Org. Lett. 2013, 15, 5106–5109. [CrossRef]
58. Zhang, W.; Xie, J.; Rao, B.; Luo, M. Iron-Catalyzed N-Arylsulfonamide Formation through Directly Using
Nitroarenes as Nitrogen Sources. J. Org. Chem. 2015, 80, 3504–3511. [CrossRef]
59. Li, X.X.; Chen, F.; Lu, G.P. Fe-Based Metal-Organic Frameworks for The Synthesis of N-Arylsulfonamides via The
Reactions of Sodium Arylsulfinates or Arylsulfonyl Chlorides with Nitroarenes in Water. Tetrahedron Lett. 2018
,
59, 4226–4230. [CrossRef]
60. Nadim, E.; Karamé, I.; Andrioletti, B. Straightforward and Sustainable Synthesis of Sulfonamides in Water
under Mild Conditions. Eur. J. Org. Chem. 2018, 5016–5022.
61. Jiang, J.; Zeng, S.; Chen, D.; Cheng, C.; Deng, W.; Xiang, J. Synthesis of N-Arylsulfonamides via Fe-Promoted
Reaction of Sulfonyl Halides with Nitroarenes in an Aqueous Medium. Org. Biomol. Chem. 2018, 16, 5016–5020.
[CrossRef]
62. Zhao, F.; Li, B.; Huang, H.W.; Deng, G.J. Palladium-Catalyzed N-Arylsulfonamide Formation from
Arylsulfonyl Hydrazides and Nitroarenes. RSC Adv. 2016, 6, 13010–13013. [CrossRef]
63. Yang, B.; Lian, C.; Yue, G.L.; Liu, D.Y.; Wei, L.Y.; Ding, Y.; Zheng, X.C.; Lu, K.; Qiu, D.; Zhao, X. Synthesis of
N-Arylsulfonamides Through A Pd-Catalyzed Reduction Coupling Reaction of Nitroarenes with Sodium
Arylsulfinates. Org. Biomol. Chem. 2018, 16, 8150–8154. [CrossRef]
64. Deruer, E.; Coulibali, S.; Boukercha, S.; Canesi, S. Carbon
−
Phosphorus Bond Formation on Anilines Mediated
by a Hypervalent Iodine Reagent. J. Org. Chem. 2017, 82, 11884–11890. [CrossRef]
65. Downer, N.K.;
Jackson, Y.A. Synthesis of Benzothiazoles via Ipso Substitution of
Orthomethoxythiobenzamides. Org. Biomol. Chem. 2004, 2, 3039–3043. [CrossRef]
66. Natarajan, A.; Guo, Y.H.; Harbinski, F.; Fan, Y.H.; Chen, H.; Luus, L.; Diercks, J.; Aktas, H.; Chorev, M.;
Halperin, J.A. Novel Arylsulfoanilide Oxindole Hybrid as an Anticancer Agent That Inhibits Translation
−
Initiation. J. Med. Chem. 2004, 47, 4979–4982. [CrossRef]
67. Aissaoui, H.; Koberstein, R.; Zumbrunn, C.; Gatfield, J.; Brisbare-Roch, C.; Jenck, F.; Treiber, A.; Boss, C.
N-Glycine-sulfonamides as Potent Dual Orexin 1/Orexin 2 Receptor Antagonists. Bioorg. Med. Chem. Lett.
2008, 18, 5729–5733. [CrossRef]
68. Sadaf, A.; Priyanka, C.; Popuri, S.; Shahulhameed, S.; Jeyakumar, K. tert-Butyl Nitrite Mediated Nitrogen
Transfer Reactions: Synthesis of Benzotriazoles and Azides at Room Temperature. Org. Biomol. Chem. 2018
16, 8280–8285.
,
Sample Availability: Not available.
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