Palladium nanoparticles as reusable catalyst for the synthesis of N-aryl sulfonamides under mild reaction conditions

Article abstract of DOI:10.1080/17415993.2015.1122010

An efficient palladium nanoparticles-catalyzed N-arylation of sulfonamides and sulfonyl azides is described. This procedure serves as an active protocol for intermolecular C-N bond formation using Pd(OAc)₂ in PEG-400 under air. Aryl bromides and triflates react at 35°C, while aryl chlorides require heating to 50°C and give the desired products only in low yields. This reaction proceeds smoothly in acceptable yields using low catalyst loading.

Full text of DOI:10.1080/17415993.2015.1122010

Journal of Sulfur Chemistry
ISSN: 1741-5993 (Print) 1741-6000 (Online) Journal homepage: http://www.tandfonline.com/loi/gsrp20
Palladium nanoparticles as reusable catalyst for
the synthesis of N-aryl sulfonamides under mild
reaction conditions
Mehdi Khalaj, Majid Ghazanfarpour-Darjani, Mohamad Reza Talei Bavil Olyai
&
Sakineh Faraji Shamami
To cite this article: Mehdi Khalaj, Majid Ghazanfarpour-Darjani, Mohamad Reza Talei Bavil
Olyai & Sakineh Faraji Shamami (2016): Palladium nanoparticles as reusable catalyst for the
synthesis of N-aryl sulfonamides under mild reaction conditions, Journal of Sulfur Chemistry,
DOI: 10.1080/17415993.2015.1122010
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Date: 18 January 2016, At: 03:37

JOURNAL OF SULFUR CHEMISTRY, 2016
http://dx.doi.org/10.1080/17415993.2015.1122010
Palladium nanoparticles as reusable catalyst for the synthesis
of N-aryl sulfonamides under mild reaction conditions
a
a
b
Mehdi Khalaj , Majid Ghazanfarpour-Darjani , Mohamad Reza Talei Bavil Olyai and
c
Sakineh Faraji Shamami
a
b
Department of Chemistry, Buinzahra Branch, Islamic Azad University, Buinzahra, Iran; Department of
c
Chemistry, Faculty of Science South Tehran Branch, Islamic Azad University, Tehran, Iran; Department of
Chemistry, Karaj Branch, Islamic Azad University, Karaj, Iran
ABSTRACT
ARTICLE HISTORY
An efficient palladium nanoparticles-catalyzed N-arylation of sulfon-
amides and sulfonyl azides is described. This procedure serves as
an active protocol for intermolecular C–N bond formation using
Pd(OAc)2 in PEG-400 under air. Aryl bromides and triflates react
at 35°C, while aryl chlorides require heating to 50°C and give the
desired products only in low yields. This reaction proceeds smoothly
in acceptable yields using low catalyst loading.
Received 29 August 2015
Accepted 16 November 2015
KEYWORDS
Sulfonamide; aryl halide; aryl
triflate; palladium
nanoparticles; C–N
Cross-coupling
Introduction
Carbon–nitrogen bonds are found in a wide range of pharmaceutical agents and natural
products.[1,2] Over the past decades, selective transition metals catalyzed carbon–nitrogen
coupling reactions have almost completely replaced classical methods of C–N bond
formation.[3–8] Among the transition metals, palladium and copper have been extensively
used due to their compatibility with functional groups, efficiency, and low toxicity. Sulfon-
amides show a wide range of biological activities such as antibacterial,[9] antitumor,[10]
and anti-HIV[11] activities. Although a variety of methods are available for the prepa-
ration of N-aryl sulfonamides, the most common way to form these compounds is the
nucleophilic attack of sulfonamide on active aryl sources.[12–22] These reactions typically
require the use of strong bases or harsh reaction conditions. Moreover, the efficient separa-
tion and subsequent recycling of homogeneous catalysts remain a scientific challenge and
result in environmental problems.
CONTACT Mehdi Khalaj
khalaj_mehdi@yahoo.com
©
2016 Taylor & Francis

2
M. KHALAJ ET AL.
The metal nanoparticles (NPs) offer high catalytic activity due to their large surface
area.[23] Generally, metal NPs are generated by a complicated process using reducing
agents and stabilizers in advance and are then utilized to catalyze a reaction thereafter.
Recently, polyethylene glycol (PEG) has been used both as the reducing agent and stabilizer
in the preparation of Pd-NPs.[24,25] Recent advances in Pd-NPs-catalyzed aerobic cou-
pling reactions [26,27] suggested to us that diverse N-aryl sulfonamides could be accessed
by aerobic C–N cross-coupling using Pd-NPs as reusable homogeneous catalyst under mild
reaction conditions.
Figure 1. TEM image of Pd nanoparticles generated using TBAA (left) and SEM image of Pd nanoparti-
cles generated using TBPA (right).
Figure 2. XRD spectra of Pd nanoparticles using TBAA.
Scheme 1. Synthesis of N-aryl sulfonamide derivatives.

JOURNAL OF SULFUR CHEMISTRY
3
In accordance with our interest in the C–N cross-coupling reactions,[28] we report a
facile Pd-NPs-catalyzed (Figures 1 and 2) N-arylation of sulfonamide precursors using
organic ionic bases in PEG-400 under air (Scheme 1).
Results and discussion
The catalyst was characterized using SEM (scanning electron microscopy), TEM (trans-
mission electron microscopy), and X-ray powder diffraction (XRD) analyses.
Typical SEM and TEM images of Pd-NPs are shown in Figure 1. The results indicated
that the nature of base highly influences the growth of the Pd-NPs. The analysis of PEG
after the reaction by NMR analyses revealed that a new peak appeared at δ = 9.50 and
1
13
1
93 ppm in H and C spectrum, respectively, which could be ascribed to the formation
of the aldehyde moiety during the reduction of Pd(II).
The coupling reaction was initially examined using p-toluenesulfonamide (1) and bro-
mobenzene (3a) in the presence of Pd(OAc) and K CO . Stirring in PEG at 35°C for 4 h
2
2
3
gave N-tosyl benzenamine (6a) in 23% yield. To develop the reaction conditions a vari-
ety of palladium salts and bases were examined (Table 1). Inorganic bases such as K PO
3
4
and NaOH or traditional monodentate and bidentate nitrogen bases such as pyridine and
DABCO failed to improve the yield of the product (Table 1, entries 2–5). A modest increase
Table 1. Optimization of reaction conditions.a
Entry
Solvent
Catalyst
Base
Yield (%)
1
2
3
4
5
6
7
8
9
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-200
PEG-600
PEG-1000
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
–
Cu(OAc)2
PdCl2
Pd(acac)2
PdO
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
K2CO3
K3PO4
NaOH
DABCO
pyridine
Cs2CO3
Bu4NOH
TBPA
TBPA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
TBAA
23
19
–
12
trace
45
47
74
b
9
1
1
1
1
1
1
1
1
1
1
2
2
a
0
1
2
3
4
5
6
7
8
9
0
1
89
b
37
c
85
–
5
trace
trace
39
d
54
–
84
89
e
f
TBAA
Reaction conditions: 1a (1.0 mmol), 3a (1.0 mmol), base (2.0 mmol), catalyst (0.02 mmol), PEG-400 (3 g), 35°C, 4 h under air.
b
c
1
1
0
.1 mmol of p-toluenesulfonyl azide (2a).
.1 mmol of (2a) and 0.05 mmol of Cu(OAc)2 were used.
.01 mmol of catalyst was used.
d
e
f
At 50°C.
At 65°C.

4
M. KHALAJ ET AL.
in the yield occurred when Cs CO was used as a base, most likely due to the better dissoci-
2
3
ation constant of Cs CO in the organic solvent (Table 1, entry 6). Gratefully, the addition
2
3
of tetrabutylphosphonium acetate (TBPA) improved the yield in an appreciable manner
Table 1, entry 8); however, conversion to 6a from the p-toluenesulfonyl azide (2a) was
(
still unsatisfactory (Table 1, entry 9). Finally, the best result was obtained when tetrabuty-
lammonium acetate (TBAA) was used in place of TBPA (Table 1, entry 10). Substantial
variation on the yield using n-Bu N as the fixed cation indicated that solubility alone does
4
not explain the utility of organic ionic bases. It was shown that ammonium ions can sta-
bilise the surface of the Pd-nanoparticulate material and this may be the origin for the
change in the average diameter of the Pd-NPs.[29] The results were consistent with the
TEM and SEM micrographs (Figure 1): the average diameters of the palladium NPs gen-
erated using TBAA were lower than those obtained in the presence of TBPA (ca. 3.2 vs
6
2 nm). The use of 0.05 mmol of Cu(OAc) as the co-catalyst highly affected the yield of
2
product when p-toluenesulfonyl azide (2a) was used as the coupling partner (Table 1, entry
2). Copper salt may assist in the decomposition of azide to corresponding nitrene which
1
has been known as an active nitrogen source. The studies also showed that the presence of a
Pd source was necessary to give the desired product in acceptable yield (Table 1, entry 13),
whereas copper (II) acetate solely was not effective in this transformation (Table 1, entry
1
4). Other Pd salts such as PdCl , Pd(acac) , and Pd(MeCN) Cl completely inhibited the
2 2 2 2
reaction likely due to the higher temperature required to form Pd-NPs. Among the other
Pd sources examined only PdO afforded the desired product in moderate yields (Table 1,
entries 15–17). To further explore the reaction conditions other types of PEG (200, 600,
and 1000) were also considered (Table 1, entries 19–21). No reaction was observed for
ethylene glycol and PEG 200 at this condition. The behaviors of PEG with higher molec-
ular weights are highly impressed by reaction temperature. PEG 600 and 1000 required
heating to 50°C and 65°C to give the desired product with the same results to that with
PEG 400. A decrease in chain in PEG might facilitate the more effective coordination of
PEG with metal ions, and hence promote the electron transfer involved in the reduction
of metal ions at lower temperatures. The effect of catalyst loading on the product yield
was also examined. The study indicated that in more cases (using different aryl bromides)
only 2 mol% of Pd-precursor could furnish the transformation; however, electron-rich sub-
strate like 1-bromo-4-methoxybenzene (3g) required comparatively higher loading of Pd
to accomplish the reaction in appropriate time.
The optimal reaction conditions (Table 1, entry 10) were proved to be effective in the
preparation of a variety of substituted N-aryl sulfonamides (Table 2). Varying the position
of the methyl substituent on the aromatic ring had little effect on the outcome of the reac-
tion; the corresponding ortho-, meta-, and para-methyl substitueted N-tosylbenzenamine
were each obtained in good yield (Table 2, entries 2–4). Electron-neutral aryl bromides
such 3a and 3k underwent very effective cross-coupling reaction under the optimized con-
ditions (Table 2, entries 1 and 11). Products containing oxo and fluoro moieties could be
obtained in high yields (Table, 2 entries 12 and 13). Notably, the tolerance for oxo moiety
on the aromatic ring offers an opportunity for subsequent reaction, facilitating expedient
synthesis of functionalized N-aryl sulfonamides. Arenes containing electron-withdrawing
functionalities gave the corresponding product in excellent yields (Table 2, entries 5, 8, and
1
0). Electron-rich substrate 3g required higher catalyst loading to accomplish the trans-
formation in proper time (Table 2, entry 7). Steric hindrance of ortho-substituent affected

JOURNAL OF SULFUR CHEMISTRY
5
Table 2. Synthesis of different N-aryl sulfonamides using aryl halides, triflates, and chlorides.a
Entry
1, R1
3
Ar
Yield (%)
Entry
4
Ar
Yield (%)
1
2
3
4
5
6
7
8
9
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1a, 4-Me
1b, H
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
a
a
a
C6H5
4-Me-C6H4
3-Me-C6H4
2-Me-C6H4
4-NO2-C6H4
2-CF3-C6H4
4-MeO-C6H4
3-CF3-C6H4
2-CN-C6H4
4-CN-C6H4
2-Naphthyl
2-CH3CO-C6H4
4-F-C6H4
6a, 89 (46)b
6b, 84
6c, 88
19
20
21
22
23
24
25
26
27
a
b
c
d
e
f
g
h
i
C6H5
6a, 83
6b, 80
6d, 63
6f, 68
6g, 80
6h, 89
6k, 83
6m, 85
6n, 78
4-Me-C6H4
2-Me-C6H4
2-CF3-C6H4
4-MeO-C6H4
3-CF3-C6H4
2-Naphthyl
4-F-C6H4
6d, 79
6e, 95 (61)b
6f, 69c
6g, 78
6h, 89 (53)b
6i, 78
2-Theinyl
10
11
12
13
14
15
16
17
18
6j, 93
6k, 87
6l, 85
6m, 85
6n, 83
6o, 91
6p, 85
6q, 90
6r, 82
2-Theinyl
2-NO2-C6H4
C6H5
1b, H
1c, 4-OMe
1d, 3-Me
C6H5
C6H5
aReaction conditions: 1 (1.0 mmol), aryl source (1.0 mmol), TBAA (2.0 mmol), PEG-400 (3 g), Pd(OAc)2 (0.02 mmol), 35°C, 4 h
under air.
b
Corresponding aryl chloride was used as the coupling partner, 50°C, 7 h under air.
c
0.05 mmol of catalyst was used.
the reaction progress; the bulky substrate 3f afforded the desired product in lower yield
(
(
Table 2, entry 6). Heteroaromatic substrate like 3n also gave the product in good yield
Table 2, entry 14). Other aryl sulfonamides also gave corresponding N-aryl sulfonamides
in acceptable yields (Table 2, entries 15–18).
Aryl triflates 4a–ai were also well tolerated and the reactions furnished the cross-
coupled products in acceptable yields (Table 2, entries 19–27). Using this procedure, no
hydrolyzed triflate was detected by NMR and GC-Mass analyses. Aryl chlorides were
not effective in this transformation and gave the corresponding products only in mod-
erate yields (Table 2, entries 1, 5, 8, and 13; digits enclosed in parentheses). Phenyl
4
-methylbenzenesulfonate did not give the desired product even at 80°C and instead the
hydrolyzed substrate was obtained in 85% yield.
The reactions of sulfonyl azides 2 with bromobenzene were also investigated. Mesyl
azide (2c) gave the desired product in lower yield, likely due to the lower nucleophilic-
ity of derived nitrene (Table 3). Generally speaking, sulfonyl azide procurers gave the
corresponding cross-coupled products in lower yields than those with sulfonamides.
To show the advantages of the proposed method in comparison with the pervious
reported methods, we summarized some of results for the C–N cross-coupling reaction,
which showed that in situ-generated NPs is almost a more effective catalyst with respect to
reaction time and yield than those methods previously reported (Table 4).
The catalytic activity of in situ-generated Pd-NPs was almost unchanged after four
cycles. In fact, we did not observe palladium black formation in the final reaction mixture

6
M. KHALAJ ET AL.
Table 3. Synthesis of different N-aryl sulfonamides using sulfonyl azides.a
2
R1
Yield (%)
a
b
c
4-Me- C6H4
6a, 79
6o, 76
6p, 68
Ph
Me
aReaction conditions: 2 (1.0 mmol), 3a (1.0 mmol), TBAA (2.0 mmol), PEG-400 (3 g), Cu(OAc)2 (0.05 mmol), Pd(OAc)2
0.02 mmol), 50°C, for 4 h under air.
(
Table 4. Comparison present methodology with other reported catalysts for the synthesis of N-aryl
sulfonamides.
Entry
Catalyst
Conditions
Ref.
1
2
3
4
5
6
7
[Pd(allyl)Cl]2
Pd2(dba)3
CuCl
Ligand, 2-MeTHF, 80°C, 6 h
Ligand, K3PO4, t-AmOH, 80°C, 18 h
MeOH, air, 25°C, 3 h
[9–11]
[12]
[13]
[14]
[20]
28b
a
Cu(OAc)2
K2CO3, H2O, reflux, 10 h
CuI + nano-Cu
Pd2(dba)3
Pd (OAc)2
DMF, Phen, K2CO3, 110°C, 24 h
Ligand, Cs2CO3, dioxane, MW, 180°C, 10 min
PEG, TBAA, 35°C, 4 h
This work
aOnly sulfonyl azides were tolerated.
Figure 3. SEM image of Pd nanoparticles after four cycles.
and the system of the palladium nanoparticles in PEG-400 was stable for a month. It was
worth noting that the average diameters of palladium particles remained at the nano size
even after four cycles (cat. 3.5 nm, Figure 1, vs 23 nm, Figure 3).
The reusability of the catalyst was then considered using bromobenzene and
p-toluenesulfonamide as the model substrates. After the completion of the reaction, the
mixture was diluted with EtOAc (3 mL) and water (15 mL). The mixture was stirred for
an additional 10 min and the organic layer separated at 25°C. The aqueous layer was dried

JOURNAL OF SULFUR CHEMISTRY
7
Table 5. Examination of catalyst reusability.a
Cycle
Yield (%)
1
2
3
4
5
6
6a, 89
6a, 88
6a, 83
6a, 82
6a, 68
6a, 46
aReaction conditions: 1a (1.0 mmol), 3a (1.0 mmol), TBAA (2.0 mmol), PEG-400 (3 g), and Pd(OAc)2 (0.02 mmol), 35°C, 4 h
under air.
in vacuo at 60°C. The residue was washed with ether (6 mL × 3) and recovered by dry-
ing at 40°C in vacuo. The catalyst was then reused for the next reaction. The catalyst
was recycled in order to test its activity as well as stability. The catalytic activity did not
change considerably even after four catalytic cycles, indicating that the catalyst could be
regenerated for subsequent use (Table 5).
In conclusion, we have reported a new procedure for the preparation of sulfonamides
using green solvent and easily available materials. To our knowledge, this work is the first
example of the Pd-NPs catalyzed aerobic C–N cross-coupling for the synthesis of N-aryl
sulfonamides under mild reaction conditions. The optimized reaction conditions given
above were compatible with the presence of functional groups such as CN, NO , CF , OMe,
2
3
F, and CH CO on the aromatic ring.
3
Experimental
All reagents were purchased from the Merck and Aldrich and used as received. Products
were characterized by different spectroscopic methods (FT-IR, Gc-Mass, and NMR), ele-
1
13
mental analysis (CHN), and melting points. H- and C-NMR spectra: Bruker DRX-500
Avance instrument; in acetone-d6 or DMSO-d6 at 500.1 and 125.7 MHz, resp. The chem-
ical shifts (δ) are reported in ppm relative to the TMS as internal standard. J values are
given in Hz. Mass: Finnigan-MAT-8430 mass spectrometer, at 70 eV; in m/z (rel. %). IR
−
1
(
KBr) spectra were recorded on a Shimadzu IR-460 spectrometer; in cm . Melting points
were taken in open capillary tubes with an Electrothermal-9100. The elemental analysis
was performed using the Heraeus CHN-O-Rapid analyzer. TLC was performed on silica
gel polygram SIL G/UV 254 plates. Morphology and particle dispersion were investigated
by SEM (Cam scan MV2300). XRD patterns were taken using Cu Kα irradiation with a
Siemens D5000 X-ray diffractometer (Philips Xpert, voltage, 40 kV; current, 100 mA).
General procedure for the preparation of N-aryl sulfonamides
A mixture of Pd(OAc) (5 mg, 0.02 mmol), aryl source (1 mmol), sulfonamide source
2
(
1.0 mmol), Cu(OAc) (9 mg, 0.05 mmol; in the presence of sulfonyl azides), and TBAA
2

8
M. KHALAJ ET AL.
(
2.0 mmol) in PEG-400 (3 g) was stirred for the appropriate time at 35–50°C under air.
The crude reaction mixture was diluted with EtOAc (5 mL) and a saturated NH Cl solu-
4
tion (5 mL). The mixture was stirred for an additional 30 min and the layers were separated.
The aqueous layer was extracted with EtOAc (6 mL × 3). The combined organic layers
were dried over MgSO , filtered, and concentrated under vacuo. The residue was puri-
4
fied by column chromatography (silica gel, hexane:EtOAc 1:3) to give the desired product.
Spectral data for all compounds except 6c, 6f, and 6n have been reported in previous
reports.[19,30,31]
3
-Methyl-N-tosylbenzenamine (6c)
Colorless solid, m.p. 91–93°C, yield: 0.23 g (88%). IR (KBr) (νmax, cm−1): 3221, 3039, 2976,
543, 1511, 1336, 1128. 1H NMR (500.1 MHz, Acetone): δH = 2.23 (3H, s, Me), 2.36 (3 H,
1
3
3
s, Me), 7.11–7.21 (m, 3 CH), 7.26 (s, CH), 7.34 (d, J = 6.7 Hz, 2 CH), 7.79 (d, J = 8.2 Hz,
1
3
2
CH), 8.75 (s, NH). C NMR (125.7 MHz, Acetone): δ = 20.6 (Me), 21.3 (Me), 117.1
C
(
(
6
CH), 118.8 (CH), 119.2 (CH), 128.6 (2 CH), 129.4 (CH), 130.9 (2 CH), 134.9 (C), 136.2
C), 140.1 (C), 144.2 (C). MS: m/z (%) = 261 (M+), 155 (6), 106 (100), 91 (24), 77 (23),
5 (12), 51 (4). Anal. Calcd for C H NO S (261.34): C, 64.34; H, 5.79; N, 5.36; S, 12.27.
14 15 2
Found: C, 64.59; H, 5.90; N, 5.41; S, 12.34%.
2-Trifluoromethyl-N-tosylbenzenamine (6f)
Colorless solid, m.p. 87–89°C, 0.22 g, yield: 69%. IR (KBr) (νmax, cm−1): 3233, 2919, 1412,
1
1
331, 1170, 933, 677. H NMR (500.1 MHz, CDCl ): δ = 2.35 (3 H, s, Me), 7.33 (2 H,
3
H
3
3
d, J = 8.15 Hz, 2 CH) 7.38–7.55 (4 H, m, 4 CH), 7.72 (2 H, d, J = 8.15 Hz, 2 CH) 9.33
1
3
(
1 H, s, NH). C NMR (125.7 MHz, Acetone): δ = 21.5 (Me), 117.2 (CH), 121.4 (CH, q,
C
3
1
JCF = 3.85 Hz), 124.4 (CH), 124.6 (CF , q, J = 270.2 Hz), 127.9 (2 CH), 130.5 (2 CH),
3
CF
2
1
(
(
31.1 (CH), 131.7 (C, q, J = 32.2 Hz), 137.5 (C), 139.8 (C), 144.9 (C). MS: m/z (%) = 315
M + 1), 160 (5), 155 (52), 91 (100), 77 (2), 65 (20), 51 (2). Anal. Calcd for C H F NO S
1
4
12
3
2
315.31): C, 53.33; H, 3.84; F, 18.08; N, 4.44; S, 10.17. Found: C, 53.58; H, 3.94; F, 18.03; N,
.41; S, 10.30%.
4
N-tosylthiophen-2-amine (6n)
Yellow oil, yield: 0.21 g (83%). IR (KBr) (νmax, cm ): 3241, 3054, 2978, 1569, 1500, 1325,
−
1
1
3
1
110. H NMR (500.1 MHz, Acetone): δ = 2.34 (3 H, s, Me), 6.21 (d, J = 6.1 Hz, CH),
H
3 3 3
6
.48 (d, J = 6.3 Hz, CH), 6.67 (t, J = 6.4 Hz, CH), 7.32 (d, J = 6.3 Hz, 2 CH), 7.79 (d,
3
13
J = 6.7 Hz, 2 CH), 8.50 (s, NH). C NMR (125.7 MHz, Acetone): δ = 24.3 (Me), 124.2
C
(
CH), 126.5 (CH), 127.2 (2 CH), 130.7 (2 CH), 131.5 (C), 137.4 (CH), 139.7 (C), 144.2 (C).
MS: m/z (%) = 253 (M+), 170 (36), 155 (52), 98 (63), 91 (78), 82 (100), 65 (12). Anal.
Calcd for C H NO S (253.34): C, 52.15; H, 4.38; N, 5.53; S, 25.31. Found: C, 52.28; H,
1
1
11
2 2
4
.48; N, 5.69; S, 25.38%.
2
-Nitro-1-phenylsulfonamidobenzene (6o)
−
1
Yellow solid, m.p. 103–105°C, 0.25 g, yield: 91%. IR (KBr) (νmax, cm ): 3294, 3061, 2982,
1
1
3
541, 1362, 1325, 1126. H NMR (500.1 MHz, Acetone): δH = 6.83 (1 H, t, J = 7.3 Hz,

JOURNAL OF SULFUR CHEMISTRY
9
3
3
CH), 6.90 (2 H, d, J = 7.9 Hz, CH), 7.20 (2 H, t, J = 7.7 Hz, 2 CH), 7.92 (1 H, t,
3
3
3
J = 7.8 Hz, 1 CH), 7.95 (1 H, t, J = 7.7 Hz, CH), 8.12 (1 H, d, J = 7.9 Hz, CH), 8.41
3
13
(
(
(
(
1 H, d, J = 7.8 Hz, CH), 9.78 (1 H, s, NH). C NMR (125.7 MHz, Acetone): δ = 120.5
C
2 CH), 121.3 (CH), 126.3 (CH), 128.4 (CH), 129.1 (C), 130.2 (2 CH), 131.6 (CH), 133.7
C), 135.2 (CH), 147.1 (C). MS: m/z (%) = 278 (M+), 201 (11), 156 (20), 137 (39), 77
100), 54 (12). Anal. Calcd for C H N O S (278.28): C, 51.79; H, 3.62; N, 10.07; S, 11.52.
1
2
10
2
4
Found: C, 51.92; H, 3.78; N, 10.19; S, 11.67%.
N-Phenylbenzenesulfonamide (6p)
−
1
Colorless solid, m.p. 109–111°C, 0.21 g, yield: 85%. IR (KBr) (νmax, cm ): 3243, 3057,
1
3
2
991, 1561, 1326, 1140. H NMR (500.1 MHz, Acetone): δ = 6.89 (1 H, t, J = 7.3 Hz,
H
3 3
CH), 6.92 (2 H, d, J = 7.9 Hz, CH), 7.23 (2 H, t, J = 7.7 Hz, 2 CH), 7.49–7.64 (5 H, m,
1
3
5
CH), 8.79 (1 H, s, NH). C NMR (125.7 MHz, Acetone): δ = 118.1 (2 CH), 122.5 (1
C
CH), 126.2 (2 CH), 128.1 (C), 129.4 (2 CH), 130.5 (1 CH), 140.2 (C). MS: m/z (%) = 233
(
M+), 156 (59), 141 (14), 92 (79), 77 (100), 54 (22). Anal. Calcd for C H NO S (233.29):
1
2
11
2
C, 61.78; H, 4.75; N, 6.00; S, 13.74. Found: C, 61.85; H, 4.78; N, 6.13; S, 13.89%.
4
-Methoxy-N-phenylbenzenesulfonamide (6q)
Colorless solid, m.p. 109–112°C, 0.24 g, yield: 90%. IR (KBr) (νmax, cm−1): 3272, 3051,
1
2
(
2
965, 1530, 1324, 1133. H NMR (500.1 MHz, Acetone): δ = 3.86 (3 H, s, OMe), 6.79
H
3
3
3
2 H, d, J = 8.9 Hz, 2 CH), 6.90 (1 H, t, J = 8.1 Hz, 1 CH), 7.05 (2 H, d, J = 7.8 Hz,
3
3
CH), 7.25 (2 H, t, J = 8.0 Hz, 2 CH), 7.53 (2 H, d, J = 8.1 Hz, 2 CH), 8.63 (1 H, s,
13
NH). C NMR (125.7 MHz, Acetone): δ = 57.2 (OMe), 113.2 (2 CH), 121.0 (2 CH),
C
1
23.3 (CH), 128.7 (2 CH), 128.0 (2 CH), 132.0 (2 CH), 135.4 (C), 142.5 (C), 159.4 (C).
MS: m/z (%) = 263 (M+), 186 (69), 171 (11), 107 (81), 77 (100), 54 (20). Anal. Calcd for
C H NO S (263.31): C, 59.30; H, 4.98; N, 5.32; S, 12.18. Found: C, 59.45; H, 4.95; N,
1
3
13
3
5
.35; S, 12.31%.
3-Methyl-N-phenylbenzenesulfonamide (6r)
Colorless solid, m.p. 88–90°C, 0.20 g, yield: 82%. IR (KBr) (νmax, cm−1): 3258, 3062, 2981,
1
1
541, 1324, 1156. H NMR (500.1 MHz, Acetone): δ = 2.37 (3 H, s, Me), 6.94 (2 H, d,
H
3
3
3
J = 7.8 Hz, 2 CH), 7.04 (1 H, t, J = 7.9 Hz, CH), 7.24 (2 H, d, J = 8.0 Hz, 2 CH), 7.48
3
3
(
1 H, d, J = 8.0 Hz, CH), 7.51 (1 H, t, J = 7.8 Hz, CH), 7.69 (1 H, s, CH), 7.79 (1 H, d,
3
13
J = 8.1 Hz, CH), 8.79 (1 H, s, NH). C NMR (125.7 MHz, Acetone): δ = 22.5 (Me),
C
1
1
(
20.6 (2 CH), 123.4 (CH), 124.0 (CH), 127.1 (CH), 129.1 (CH), 129.3 (C), 130.7 (2 CH),
33.1 (CH), 139.5 (C), 140.5 (C). MS: m/z (%) = 247 (M+), 170 (51), 155 (16), 92 (71), 91
51), 77 (100). Anal. Calcd for C H NO S (247.31): C, 63.14; H, 5.30; N, 5.66; S, 12.96.
13 13 2
Found: C, 63.27; H, 5.41; N, 5.72; S, 12.93%.
Acknowledgements
We also gratefully acknowledge from the Iranian Nano Council for the support of this work.

10
M. KHALAJ ET AL.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was supported by the Islamic Azad University of IRAN, Buinzahra branch (research
grant).
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