NH4I/1,10-phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl arylsulfinates

Article abstract of DOI:10.1016/j.tet.2019.130664

An efficient synthesis of N-heterocyclic aryl sulfides via NH₄I/1,10-phenanthroline-catalyzed direct sulfenylation reactions was reported. In this reaction, heteroarenes such as indoles, and pyrroles serve as nucleophiles by installing a arylthio group at the C3 and C2 position of heterocycles, respectively. With readily accessible and free of unpleasant odor ethyl arylsulfinates as sulfur reagents, the metal-free-catalyzed direct sulfenylation of N-heteroarenes has been developed. 3-Arylthio-indoles and 2-arylthio-pyrroles derivatives were obtained in moderate to excellent yields, even on gram scale. The reaction was general for a broad scope of substrates and demonstrated good tolerance to a variety of functional groups.

Full text of DOI:10.1016/j.tet.2019.130664

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NH I/1,10-phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl
4
arylsulfinates
Lingjuan Chen, Jun Zhang, Yueting Wei, Zhen Yang, Ping Liu, Jie Zhang, Bin Dai
PII:
S0040-4020(19)31033-6
https://doi.org/10.1016/j.tet.2019.130664
TET 130664
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 28 July 2019
Revised Date: 14 September 2019
Accepted Date: 29 September 2019
Please cite this article as: Chen L, Zhang J, Wei Y, Yang Z, Liu P, Zhang J, Dai B, NH I/1,10-
4
phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl arylsulfinates, Tetrahedron
(2019), doi: https://doi.org/10.1016/j.tet.2019.130664.
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NH4I/1,10-Phenanthroline catalyzed direct
sulfenylation of N-heteroarenes with ethyl
arylsulfinates
Leave this area blank for abstract info.
Lingjuan Chen, Yueting Wei, Zhen Yang, Ping Liu*, Jie Zhang*, Bin Dai
aSchool of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical
Engineering of Xinjiang Bingtuan，Shihezi University, Shihezi 832003, China

1
Tetrahedron
journal homepage: www.elsevier.com
NH4I/1,10-Phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl
arylsulfinates
Lingjuan Chen, Jun Zhang, Yueting Wei, Zhen Yang, Ping Liu*, Jie Zhang*, Bin Dai
aSchool of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan
Shihezi 832003, China
，Shihezi University,
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
An efficient synthesis of N-heterocyclic aryl sulfides via NH4I/1,10-phenanthroline-catalyzed
direct sulfenylation reactions was reported. In this reaction, heteroarenes such as indoles, and
pyrroles serve as nucleophiles by installing a arylthio group at the C3 and C2 position of
heterocycles, respectively. With readily accessible and free of unpleasant odor ethyl
arylsulfinates as sulfur reagents, the metal-free-catalyzed direct sulfenylation of N-heteroarenes
has been developed. 3-Arylthio-indoles and 2-arylthio-pyrroles derivatives were obtained in
moderate to excellent yields, even on gram scale. The reaction was general for a broad scope of
substrates and demonstrated good tolerance to a variety of functional groups.
Available online
Keywords:
sulfenylation
ethyl arylsulfinates
indole
2009 Elsevier Ltd. All rights reserved
.
pyrrole
metal-free
1. Introduction
In 2018, Yang co-workers reported an excellent catalyst-free
directed 3-sulfenylation to prepare 3-arylsulfinylindoles, in
which the sulfinic esters were employed as readily accessible and
free of unpleasant odor sulfur reagents in their strategy (Scheme
1a).[94] However, this method still has certain deficiencies, for
example: (i) this system only limits to the 3-sulfenylation of
indoles and is not suitable for the 2-sulfenylation of pyrroles; (ii)
the amount of indoles must be excessive, and the results show the
sulfenylation of indoles is difficult to occur in the presence of
excessive aryl sulfinic esters; (iii) the 3-sulfenylation of indoles
afford the only 38-88% yields for 12 h. As a consequence, the
development of efficient protocols for the sulfenylation of N-
heteroarenes with good yields, broad scope of substrates, and
shorter reaction times is highly desirable and remains a synthetic
challenge. Recently, we developed an efficient method for the
synthesis of sulfinic esters via the copper-catalyzed reaction of
sulfonyl hydrazides with alcohols in air, and various arylsulfinic
esters were obtained in good yields.[95] Based on our previous
work,[96, 97] we herein describe a new strategy to access 3-arylthio-
indoles and 2-arylthio-pyrroles by NH4I/1,10-phenanthroline
catalyzed direct sulfenylation of N-heteroarenes with ethyl
arylsulfinates (Scheme 1b). The remarkable achievements of this
catalytic system are: (i) this method is not only suitable for the 3-
sulfenylation of indoles, but also for the 2-sulfenylation of
pyrroles; (ii) the direct sulfenylation of N-heteroarenes including
indoles and pyrroles proceeds smoothly in the presence of
slightly excessive aryl sulfinic esters to give the desired products
in 43-99% yields; (iii) the reaction time was shortened to 6 h in
the presence of NH4I/1,10-phenanthroline as catalyst.
Sulfur-containing compounds are important structural motifs
that are widely present in various drugs, pesticides, food
ingredients, and material molecules.[1,2] Therefore, effective
methods for formation of sulfur-carbon bonds have been
attracting attention.[3-20] Indoles and pyrroles, as vital heterocyclic
structural skeletons, have been widely found in natural
compounds and valuable pharmacological drugs.[21-26] Numerous
studies have shown that the introduction of sulfur-containing
groups into indole molecules increases both chemical structure
diversity and biological activity of the compounds.[27-35]
Therefore, the selective formation of carbon-sulfur (C-S) bonds
of indoles has become an important field of organic chemistry.[36-
41]
In recent years, direct sulfenylation of indoles to the synthesis
of 3-arylsulfinylindoles have been paid much attention. Various
sulfur reagents such as arylsulfonyl chlorides,[42-47] sodium
sulfinates,[48-54] sulfenyl halides,[55-59] N-thioimides,[60-68] thiols,[69-
75]
disulfides,[76-81] quinone mono-O,S-acetals,[82-84] sulfonyl
hydrazides,[85-89] N-hydroxy sulfonamides,[90] sulfinic acids,[91,92]
and sulfonium salts[93] have been employed for sulfenylation
reactions. Despite the significant advances of direct sulfenylation,
most of the established protocols are suffered from some
disadvantages, including some sulfur agents which are unstable
to air and moisture, not readily available or have an unpleasant
odour, the use of metal catalysts, some of these reactions require
excess additives as well as high temperatures or yield byproducts
unfriendly to the environment. To address such issues, it is highly
desirable to develop new sulfenylating agents and efficient
reaction conditions for the sulfenylation of N-heteroarenes.

2
Tetrahedron
[a] Yang's work
control experiment confirmed the essential action of the iodine
Ar
S
Ar
S
O
S
catalyst (entry 15). Subsequently, the R group substituent on the
benzenesulfinate such as either methyl or n-propyl group (2b or
2c) was examined, a decrease in yield was observed (entries 16
and 17). However, by employing n-butyl group comparable
results were obtained (95%, entry18). Finally, the combination of
1H-indole (0.3 mmol), ethyl benzenesulfinate (0.4 mmol), NH4I
(20 mol%), 1,10-phenanthroline (10 mol%), HOAc (0.5 mL) at
100 °C for 6 h in 1,4-dioxane (2 mL) was found to be the optimal
reaction conditions.
EtOH
EtOH
+
N
H
N
H
Ar
OEt
N
H
(1.8 equiv.)
38-88% yields
[b] This work
Ar
S
Ar
S
O
S
20% NH4I
10% 1,10-Phen.
20% NH4I
+
10% 1,10-Phen.
Ar
OEt
N
N
N
H
H
H
(≈1.3 equiv.)
60-99% yields
43-86% yields
Scheme 1. Sulfenylation of N-heteroarenes.
2. Results and Discussion
2.2. Scope and limitations of substrates
With the optimized conditions in hand, the reaction scope with
respect to substituted indoles was examined (Table 2). The
obtained results indicated that substituted indoles bearing methyl
and methoxy groups on the aromatic rings reacted with ethyl
benzenesulfinate 2a affording products 3b-3e in good yields. The
introduction of halogens on the aromatic rings provided products
3f-3h in good yields, which are potential substrates for further
transition-metal-catalyzed functionalization. No obvious steric
influence was observed when using 2- or 4-substituted indoles as
substrates, giving desired products 3i-3n in 52-91% yields.
Notably, with 1H-indole-4-carbonitrile as the substrate, the
product 3j was obtained in 96% yield after 12 h. Furthermore, in
the case of 1H-pyrrolo[2,3-b]pyridine the product 3o was
provided in 64% yield at 120 ºC. When 1-methyl-1H-indole was
reacted with 2a, the desired product 3p was provided in 73%
yield. To demonstrate the robustness and practicality of this
method, a gram-scale reaction of 1a (5 mmol) and 2a (6 mmol)
was conducted affording the product 3a (1.021 g) in 95% yield.
2.1. Optimization of the reaction conditions
Table 1. Optimized reaction conditions [a]
Entry
1
2
[I](mol%)
T
Time Solvent
Yield(%)b
45
2a KI(20)
80
10
10
10
10
10
10
6
DCE
2
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
2a NH4I(20)
80
DCE
59
3
4c
5d
6e
7c
8c
9c
10c
11c
12c
13c
14c
15c
16c
17c
80
DCE
66
80
DCE
82
80
DCE
68
80
DCE
82
80
DCE
82
Table 2. Substrate scope of substituted indoles [a]
80
6
DCE
82
100
100
100
100
100
100
100
100
100
6
DCE
92
6
DMSO
DMF
trace
trace
34
6
6
EtOH
6
toluene
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
62
6
98
2a
̶
6
trace
68
2b NH4I(20)
2c NH4I(20)
6
6
83
18c
NH4I(20)
100
6
1,4-dioxane
95
2d
[a] Reaction conditions: 1a (0.3 mmol), 2 (entries 1-7, 0.6 mmol; entries 8-18,
0.4 mmol), solvent (2 mL), HOAc (entries 3-17, 0.5 mL). [b]Isolated yield.
[d]
[c]1,10-phenanthroline (10 mol%). PPh3 (10 mol%).[e]1,10-phenanthroline
(20 mol%).
[a] Reaction conditions: 1 (0.3 mmol), 2a (0.4 mmol), NH4I (20 mol%), 1,10-
phenanthroline (10 mol%), 100 ºC, 6 h, 1,4-dioxane (2 mL), HOAc (0.5 mL).
The yields of isolated products are given. [b]1a (5 mmol) and 2a (6 mmol)
were used.[c]t = 12 h. [d]T = 120 ºC.
Optimization of the conditions utilized 3-sulfenylation of 1H-
indole 1a (0.3 mmol) and ethyl benzenesulfinate 2a (0.6 mmol)
as the model reaction, with 20 mol% KI as catalyst at 80 °C in
dichloroethane (DCE) as solvent (Table 1). The preliminary
reaction gave desired product 3-(phenylthio)-1H-indole 3a in
45% yield after 10 h (entry 1). When NH4I was used as the
catalyst, the product 3a was obtained in 59% yield (entry 2). By
employing the 0.5 mL of HOAc, a 66% yield was observed
(entry 3). Additives such as 1,10-phenanthroline and PPh3 were
examined, respectively, 10 mol% of 1,10-phenanthroline was
found to be the optimum choice (entries 4-6). A decrease in both
the amount of 2a (0.4 mmol) and reaction time (6 h) had no
influence on the reaction yield (entries 7-8). By increasing the
temperature to 100 ºC, the yield of 3a was improved to 92%
(entry 9). Further screening of solvents revealed that 1,4-dioxane
was the best choice (98% yield, entry14 vs entries 10-13). A
We next investigated the scope of substituted ethyl
arylsulfinates. As indicated in Table 3, this protocol was
amenable to ethyl arylsulfinates bearing either electron-donating
or electron-withdrawing substituents on the phenyl ring, leading
to the desired products 3q-4c in 75-99% yields. It should be
noted that the substituent position had no significant effect on the
substrate activity. Ethyl naphthalene-2-sulfinate was also suitable
for this transformation and gave the product 4d in 82% yield.
Notably, the introduction of a methyl group at 2-position on ethyl
arylsulfinate, afforded the desired product 4e in 60% yield.

3
Table 3. Substrate scope of ethyl arysulfinates [a]
O
S
F
OEt
EtOH, 90 ºC, 12 h
[a]
[b]
Me
S
Me
F
N
N
O
F
S
4d
OEt
this work, 63% yield
Scheme 2. Comparison of reaction systems.
Subsequently, to gain insight into the mechanism, a series of
control experiments were performed (Scheme 3). With the
addition of radical scavenger TEMPO (3 equiv.) under standard
reaction conditions, the 3-sulfenylation was not completely
inhibited and still gave the desired product 3a in 15% yield.
Moreover, when hydroquinone and 2,6-di-tert-butyl-4-
methylphenol (BHT) as radical scavengers were used, the
reactions proceeded smoothly and gave yields of 60% and 56%,
respectively. So we speculated that this may not be a radical
mechanistic pathway (Scheme 3a). When benzyl 4-methyl
benzenesulfinate as sulfur reagent was subjected to the standard
conditions, the desired product 3q was formed in 30% yield,
while 40% yield of benzyl alcohol was also detected by GC-MS
(Scheme 3b). When only ethyl benzenesulfinate as substrate is
used, 1,2-di-p-tolyldisulfane can be obtained in 26% yield under
normal reaction conditions (Scheme 3c). Subsequently, the 1,2-
di-p-tolyldisulfane was employed instead of benzyl 4-
methylbenzenesulfinate, the desired product 3a was obtained in
25% yield, thus suggesting that this reaction may involve a
mechanistic pathway of 1,2-di-p-tolyldisulfane formation
(Scheme 3d). In addition, in the presence of HI (40% aqueous
solution), the target product was also obtained in 19% yield,
indicating that iodine anion isessential during the 3-sulfenylation
of indole (Scheme 3e).
[a] Reaction conditions: 1a (0.3 mmol), 2 (0.4 mmol), NH4I (20 mol%), 1,10-
phenanthroline (10 mol%), 100 ºC, 6 h, 1,4-dioxane (2 mL), HOAc (0.5 mL).
The yields of isolated products are given.
To further expand the scope of this reaction, pyrroles were
explored under the optimized conditions. As shown in Table 4, 1-
methyl-1H-pyrrole underwent reactions with various ethyl
arylsulfinates to generate the corresponding 1-methyl-2-
(arylthio)-1H-pyrroles products 4f-4m in 54-86% yields.
Moreover, 1H-pyrrole also underwent this transformation
smoothly, affording the desired products 4n-4q with 48-66%
yields. In addition, 2-methyl-1H-pyrrole was also suitable for this
transformation and gave the products 4r-4u in 43-70% yields.
Table 4. Substrate scope of pyrroles [a]
NH4I
1,10-phenanthroline
R
R
O
S
R'
N
R'
N
+
Ar
1,4-dioxane,
HOAc, 100 oC, 6 h
Ar
R
OEt
S
2
4
1
4f
, R = 4-F, 63%
4g, R = 4-Cl, 69%
, R = 4-Br, 77%
NMe
S
NMe
4h
4i
, R = 4-NO2, 69%
S
4m
4j, R = 4-CN, 86%
4k
4l
, 54%
, R = 3-CF3, 66%
, R = 3-Br, 68%
NH
4n
, R = 4-Br, 66%
4o, R = 4-NO2, 56%
NH
S
R
S
4p
, R = 3-Br, 62%
4r
, R = 4-Me, 65%
4q,
48%
H
Me
S
N
Me
NH
R
4s, R = 4-NO2, 70%
S
4t, 43%
[a]Reaction conditions: 1 (0.3 mmol), 2 (0.4 mmol), NH4I (20 mol%), 1,10-
phenanthroline (10 mol%), 100 ºC, 6 h, 1,4-dioxane (2 mL), HOAc (0.5 mL).
The yields of isolated products are given.
Next, we compared our approach to Zhou and Yang et.al
reported 3-sulfenylation of indoles using ethyl benzenesulfinate
as the sulfur source,[94] and these results were summarized in
Scheme 2. When 1-methyl-1H-pyrrole as substrate reacted with
ethyl benzenesulfinate in EtOH at 90 ºC, the desired product 4d
was not observed (Scheme 2a). Instead, this reaction proceeds
smoothly under our standard conditions to give the desired
product in 63% yield (Scheme 2b). Therefore, the developed
catalytic system has a much wider substrate scope compared to
above reported method.
Scheme 3. Control experiments
On the basis of the above investigations, a possible
mechanistic pathway is depicted in Scheme 4. The reaction is
initiated by the protonation of ethyl arylsulfinate under acidic
conditions and addition of iodine anion resulting in intermediate
(I), which subsequently goes through the loss of an ethanol to
form arylsulfinic iodide (II). The intermediate (II) is
successively reduced into the intermediates (III) and (IV) in the
presence of hydroiodic acid.[109] Moreover, the aryl
hypoiodothioite (IV) produces diaryl disulfide and elemental

4
Tetrahedron
iodine by reversible reaction. Next, the intermediate (IV)
acetate (5 mL × 3). The combined organic layers were dried over
anhydrous MgSO4 and concentrated in vacuo. The crude was
purified by flash column chromatography with Al2O3 (petroleum
ether/EtOAc) giving desired products 3a-z and 4a-r.
directly reacts with 1H-indole by electrophilic substitution to
afford the desired product 3. In addition, 1H-pyrrol reacts with
the intermediate (IV) by electrophilic addition to produce the
desired product 4.
4.3. 3-(Phenylthio)-1H-indole [3a][98]
1
White solid, mp 121.3-122.6 oC; H NMR (400 MHz, CDCl3)
δ 8.33 (s, 1H), 7.61 (d, J = 8.0 Hz, 1H), 7.46-7.38 (m, 2H), 7.29-
7.22 (m, 1H), 7.15 (td, J = 7.8, 3.2 Hz, 3H), 7.10 (d, J = 6.8 Hz,
2H), 7.04 (t, J = 7.2 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ
139.34, 136.61, 130.81, 129.22, 128.82, 125.97, 124.90, 123.18,
121.04, 119.80, 111.71, 102.95.
4.4. 5-Methyl-3-(phenylthio)-1H-indole [3b] [99]
1
White solid, mp 160.9-161.3 oC; H NMR (400 MHz, CDCl3)
δ 8.19 (s, 1H), 7.32 (s, 1H), 7.27 (d, J = 2.8 Hz, 1H), 7.18 (d, J =
8.4 Hz, 1H), 7.08-7.03 (m, 2H), 7.02-6.92 (m, 4H), 2.31 (s, 3H);
13C NMR (101 MHz, CDCl3) δ 139.61, 134.87, 131.08, 130.47,
129.48, 129.20, 128.82, 125.72, 124.77, 119.20, 111.41, 101.84,
21.55;
4.5. 5-Methoxy-3-(phenylthio)-1H-indole [3c] [100]
1
Pale yellow oil; H NMR (400 MHz, CDCl3) δ 8.38 (s, 1H),
7.40 (d, J = 2.8 Hz, 1H), 7.28 (d, J = 8.8 Hz, 1H), 7.18-7.13 (m,
2H), 7.11-7.02 (m, 4H), 6.90 (dd, J = 8.8, 2.8 Hz, 1H), 3.76 (s,
3H); 13C NMR (101 MHz, CDCl3) δ 155.24, 139.46, 131.47,
130.08, 128.83, 125.77, 124.83, 113.71, 112.57, 102.24, 100.90,
55.91.
Scheme 4. Proposed mechanism.
3. Conclusions
4.6. 7-Methyl-3-(phenylthio)-1H-indole [3d] [99]
In summary, we realized a NH4I/1,10-phenanthroline direct
sulfenylation reaction of N-heteroarenes including indoles, and
pyrroles. In contrast to classical reactions, the reaction features
remarkably metal-free conditions, readily available ethyl
arylsulfinates as sulfur reagents, and facile synthesis of 3-
arylthio-indoles and 2-arylthio-pyrroles. The good reactivity,
broad substrate scope, and scalability of this method suggest that
this protocol can be a powerful alternative to the existing
methodologies for the synthesis of structurally diverse N-
heterocyclic aryl sulfides. Importantly, the grams scale synthesis
was also accomplished.
1
Blue oil; H NMR (400 MHz, CDCl3) δ 8.28 (s, 1H), 7.45 (d,
J = 7.2 Hz, 1H), 7.38 (s, 1H), 7.14-7.01 (m, 7H), 2.47 (s, 3H);
13C NMR (101 MHz, CDCl3) δ 139.36, 136.16, 130.57, 128.80,
128.77, 125.93, 124.87, 123.67, 121.16, 120.92, 117.43, 103.11,
16.54.
4.7. 7-Methoxy-3-(phenylthio)-1H-indole [3e] [101]
Blue solid, mp 115.2-116.3 oC; 1H NMR (400 MHz, CDCl3) δ
8.62 (s, 1H), 7.40 (d, J = 2.8 Hz, 1H), 7.20 (d, J = 8.0 Hz, 1H),
7.17-6.99 (m, 6H), 6.68 (d, J = 7.6 Hz, 1H), 3.95 (s, 3H); 13C
NMR (101 MHz, CDCl3) δ 146.41, 139.48, 130.66, 130.31,
128.78, 127.16, 125.92, 124.82, 121.43, 112.31, 103.14, 102.88,
55.54.
4. Experimental Section
4.1. Materials and instruments
4.8. 6-Fluoro-3-(phenylthio)-1H-indole [3f] [102]
Unless otherwise noted, all synthetic steps were performed
under air atmosphere using Schlenk tubes. The materials
obtained from commercial sources were used without further
purification. 1,4-Dioxane was distilled from Na/benzophenone.
Melting points were determined with a fusiometer and are not
1
White solid, mp 161.7-162.5 oC; H NMR (400 MHz, CDCl3)
δ 8.36 (s, 1H), 7.50 (dd, J = 8.8, 5.2 Hz, 1H), 7.46 (d, J = 2.8 Hz,
1H), 7.19-7.14 (m, 2H), 7.13-7.04 (m, 4H), 6.91 (ddd, J = 9.6,
8.8, 2.0 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 161.80, 138.97,
136.59, 136.46, 131.02, 130.98, 128.89, 126.06, 125.08, 120.80,
120.70, 110.03, 109.79, 103.42, 98.28, 98.01.
1
corrected. H NMR and 13C NMR spectra were recorded on a
Bruker Advance III HD 400 MHz spectrometer in CDCl3
solution. All chemical shifts were reported in ppm (δ) relative to
the internal standard TMS (0 ppm).
4.9. 5-Chloro-3-(phenylthio)-1H-indole [3g] [103]
White solid, mp 167.2-168.1 oC; H NMR (400 MHz, CDCl3)
4.2. General Procedure for the NH4I/1,10-Phenanthroline
Catalyzed direct sulfenylation of N-heteroarenes with ethyl
arylsulfinates
1
δ 8.45 (s, 1H), 7.59 (d, J = 1.6 Hz, 1H), 7.51 (d, J = 2.8 Hz, 1H),
7.35 (d, J = 8.4 Hz, 1H), 7.21 (dd, J = 8.4, 2.0 Hz, 1H), 7.20-7.15
(m, 2H), 7.11-7.04 (m, 3H); 13C NMR (101 MHz, CDCl3) δ
138.79, 132.15, 128.94, 126.00, 125.16, 123.70, 123.64, 120.68,
119.20, 112.82, 112.50, 102.85.
A Schlenk tube (25 mL) was charged with indole (0.3 mmol),
ethyl arylsulfinate (0.4 mmol), NH4I (20 mol%), and 1,10-
phenanthroline (10 mol%). 1,4-Dioxane (2 mL) and HOAc (0.5
mL) were added under air atmosphere, the tube was sealed and
4.10. 6-Bromo-3-(phenylthio)-1H-indole [3h] [100]
o
heated in an oil bath at 100 C for 6 h. The crude mixture was
1
allowed to cool to room temperature. Then, ethyl acetate and
saturated aq. solution of NaCl (5 mL) were added and the layers
separated. The aqueous phase was washed three times with ethyl
White solid, mp 160.9-161.3 oC; H NMR (400 MHz, CDCl3)
δ 8.43 (s, 1H), 7.56 (d, J = 1.2 Hz, 1H), 7.47-7.40 (m, 2H), 7.27-
7.22 (m, 1H), 7.19-7.12 (m, 2H), 7.07 (d, J = 8.0 Hz, 3H); 13C

5
NMR (101 MHz, CDCl3) δ 138.81, 137.35, 131.26, 128.90,
White solid, mp 137.6-138.8 oC; 1H NMR (400 MHz,
128.12, 126.06, 125.14, 124.40, 121.11, 116.79, 114.69, 103.57.
CDCl3) δ 8.35 (s, 1H), 7.61 (d, J = 8.0 Hz, 1H), 7.47 (d, J = 2.0
Hz, 1H), 7.42 (d, J = 8.0 Hz, 1H), 7.28-7.23 (m, 2H), 7.18-7.13
(m, 1H), 7.03 (d, J = 8.4 Hz, 2H), 6.97 (d, J = 8.0 Hz, 2H), 2.24
(s, 3H); 13C NMR (101 MHz, CDCl3) δ 136.59, 135.60, 134.77,
130.53, 129.61, 129.25, 126.39, 120.96, 119.84, 111.65, 103.68,
21.00.
4.11. 4-Nitro-3-(phenylthio)-1H-indole [3i]
Yellow solid, mp 148.7-149.5 oC; 1H NMR (400 MHz,
CDCl3) δ 9.14 (s, 1H), 7.73 (d, J = 7.6 Hz, 1H), 7.68 (d, J = 8.0
Hz, 1H), 7.58 (d, J = 2.4 Hz, 1H), 7.34-7.26 (m, 1H), 7.20-7.13
(m, 2H), 7.13-7.02 (m, 3H); 13C NMR (101 MHz, CDCl3) δ
143.47, 139.15, 138.98, 135.07, 128.90, 127.01, 125.51, 122.09,
120.29, 117.97, 117.07, 103.63.
4.20. 3-((4-(Tert-butyl)phenyl)thio)-1H-indole [3r] [94]
o
1
Pale yellow solid, mp 153.4-153.9 C; H NMR (400 MHz,
CDCl3) δ 8.34 (s, 1H), 7.64 (d, J = 8.0 Hz, 1H), 7.46-7.39 (m,
2H), 7.28-7.23 (m, 1H), 7.20-7.15 (m, 3H), 7.07-7.03 (m, 2H),
1.24 (s, 9H);13C NMR (101 MHz, CDCl3) δ 147.95, 136.45,
135.73, 130.59, 130.35, 129.28, 125.79, 122.99, 120.84, 119.74,
111.55, 34.32, 31.32.
4.12. 3-(Phenylthio)-1H-indole-4-carbonitrile [3j] [104]
White solid, mp 156.3-158.2 oC; 1H NMR (400 MHz, DMSO-
d6) δ 12.33 (s, 1H), 8.05 (d, J = 2.8 Hz, 1H), 7.86 (dd, J = 8.4, 0.8
Hz, 1H), 7.58 (dd, J = 7.6, 0.8 Hz, 1H), 7.39-7.31 (m, 1H), 7.23
(t, J = 7.6 Hz, 2H), 7.13-7.01 (m, 3H); 13C NMR (101 MHz,
DMSO-d6) δ 139.52, 137.13, 136.51, 128.90, 127.70, 127.47,
125.55, 125.01, 122.16, 117.76, 117.74, 101.08, 99.36.
4.21. 3-((4-Methoxyphenyl)thio)-1H-indole [3s] [94]
1
White solid, mp 138.0-138.6 oC; H NMR (400 MHz, CDCl3)
δ 8.34 (s, 1H), 7.62 (d, J = 8.0 Hz, 1H), 7.45-7.36 (m, 2H), 7.27-
7.20 (m, 1H), 7.16-7.09 (m, 3H), 6.75-6.71 (m, 2H), 3.71 (s,
3H);13C NMR (101 MHz, CDCl3) δ 157.88, 136.56, 133.79,
130.14, 128.67, 123.05, 120.89, 119.76, 115.28, 114.60, 111.64,
104.71, 55.46.
4.13. 3-(Phenylthio)-4-(trifluoromethyl)-1H-indole [3k]
White solid, mp 190.2-190.6 oC 1H NMR (400 MHz, CDCl3)
;
δ 8.70 (S, 1H), 7.58 (d, J = 8.0, 1H), 7.54 (d, J = 8.0, 2H), 7.27 (t,
J = 8.0, 1H), 7.14 (t, J = 8.0, 2H), 7.03 (d, J = 8.0, 2H). 13C NMR
(101 MHz, CDCl3) δ 140.51, 137.85, 135.11, 128.55, 125.64,
124.64, 121.91, 119.74, 119.67, 119.61, 119.55, 115.93, 102.06.
19F NMR (376 MHz, CDCl3) δ -57.58.
4.22. 3-((4-Fluorophenyl)thio)-1H-indole [3t] [94]
1
White solid, mp 148.5-149.0 ºC; H NMR (400 MHz, CDCl3)
δ 8.39 (s, 1H), 7.59 (d, J = 8.0 Hz, 1H), 7.48-7.41 (m, 2H), 7.29-
7.24 (m, 1H), 7.19-7.14 (m, 1H), 7.11-7.06 (m, 2H), 6.89-6.83
(m, 2H); 13C NMR (101 MHz, CDCl3) δ 162.24, 159.81, 136.62,
134.15, 134.12, 130.62, 128.98, 128.05, 127.97, 123.26, 121.10,
119.65, 115.98, 115.76, 111.76, 103.52.
4.14. Methyl 3-(phenylthio)-1H-indole-4-carboxylate [3l]
1
White solid, mp 188.2-188.6 oC; H NMR (400 MHz, CDCl3)
δ 9.14 (S, 1H), 7.47 (d, J = 8.0, 2H), 7.39 (s, 1H), 7.22 (t, J = 8.0,
1H), 7.12 (t, J = 8.0, 2H), 7.02 (t, J = 8.0, 3H), 3.58 (s, 3H). 13C
NMR (101 MHz, CDCl3) δ 169.63, 140.18, 137.57, 133.91,
128.61, 125.60, 125.38, 125.24, 124.64, 122.20, 122.10, 115.21,
101.98, 51.97.
4.23. 3-((4-Chlorophenyl)thio)-1H-indole [3u] [94]
1
White solid, mp 137.6-138.8 oC; H NMR (400 MHz, CDCl3)
δ 8.39 (s, 1H), 7.57 (d, J = 8.0 Hz, 1H), 7.48 (d, J = 2.8 Hz, 1H),
7.44 (d, J = 8.4 Hz, 1H), 7.30-7.25 (m, 1H), 7.20-7.14 (m, 1H),
7.11 (d, J = 8.4 Hz, 2H), 7.01 (d, J = 8.8Hz, 2H); 13C NMR (101
MHz, CDCl3) δ 137.92, 136.63, 130.84, 130.68, 128.92, 128.88,
127.23, 123.35, 121.20, 119.64, 111.80, 102.56.
4.15. 2-Methyl-3-(phenylthio)-1H-indole [3m] [100]
1
White solid, mp 118.3-120.0 oC; H NMR (400 MHz, CDCl3)
δ 8.16 (s, 1H), 7.54 (d, J = 7.6 Hz, 1H), 7.29 (d, J = 8.0 Hz, 1H),
7.21-7.14 (m, 2H), 7.14-7.08 (m, 3H), 7.05-6.99 (m, 3H), 2.45 (s,
3H); 13C NMR (101 MHz, CDCl3) δ 141.29, 139.45, 135.54,
130.38, 128.80, 125.58, 124.62, 122.27, 120.79, 119.06, 110.79,
99.35, 12.24.
4.24. 3-((4-Bromophenyl)thio)-1H-indole [3v] [98]
1
White solid, mp 149.5-151.6 oC; H NMR (400 MHz, CDCl3)
δ 8.39 (s, 1H), 7.61-7.54 (m, 1H), 7.50-7.42 (m, 2H), 7.31-7.23
(m, 3H), 7.22-7.13 (m, 2H), 6.95 (dd, J = 8.8, 2.4 Hz, 2H); 13C
NMR (101 MHz, CDCl3) δ 138.65, 136.61, 131.76, 130.86,
128.88, 127.51, 123.35, 121.21, 119.62, 118.43, 111.81, 102.36.
4.16. 5-Chloro-2-methyl-3-(phenylthio)-1H-indole [3n] [77]
1
White solid, mp 135.9-136.7 oC; H NMR (400 MHz, CDCl3)
δ 8.28 (s, 1H), 7.51 (d, J = 2.0 Hz, 1H), 7.23 (t, 1H), 7.19-7.09
(m, 3H), 7.08-6.98 (m, 3H), 2.48 (s, 3H); 13C NMR (101 MHz,
CDCl3) δ 142.84, 138.94, 133.88, 131.73, 128.92, 126.72, 125.61,
124.87, 122.61, 118.59, 111.81, 99.47, 12.33.
4.25. 3-((4-Nitrophenyl)thio)-1H-indole [3w] [103]
Yellow solid, mp 121.2-121.7 oC; 1H NMR (400 MHz,
CDCl3) δ 8.71 (s, 1H), 8.02-7.96 (m, 2H), 7.58-7.45 (m, 3H),
7.36-7.26 (m, 1H), 7.23-7.15 (m, 1H), 7.15-7.08 (m, 2H); 13C
NMR (101 MHz, CDCl3) δ 150.00, 144.98, 136.72, 131.38,
128.54, 125.20, 123.98, 123.64, 121.51, 119.30, 112.10, 100.19.
4.17. 3-(Phenylthio)-1H-pyrrolo (2,3-b) pyridine [3o] [103]
o
1
Pale yellow solid, mp 147.6-147.9 C; H NMR (400 MHz,
CDCl3) δ 11.67 (s, 1H), 8.41 (dd, J = 4.8, 1.2 Hz, 1H), 7.95 (dd, J
= 7.6, 1.2 Hz, 1H), 7.70 (s, 1H), 7.22-7.12 (m, 3H), 7.14-7.03 (m,
3H); 13C NMR (101 MHz, CDCl3) δ 149.27, 143.45, 138.89,
132.02, 128.93, 128.67, 126.15, 125.21, 122.31, 116.97, 101.58.
4.26. 3-((4-(Trifluoromethyl)phenyl)thio)-1H-indole [3x] [105]
1
White solid, mp 134.0-134.6 oC; H NMR (400 MHz, CDCl3)
δ 8.46 (s, 1H), 7.56 (d, J = 7.6 Hz, 1H), 7.49-7.43 (m, 2H), 7.37
(d, J = 8.4 Hz, 2H), 7.34-7.22 (m, 1H), 7.21-7.16 (m, 1H), 7.13
(d, J = 8.2 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 136.67,
131.16, 128.86, 125.67, 125.63, 125.59, 125.55, 125.39, 123.49,
121.35, 119.55, 111.91, 101.34. 19F NMR (376 MHz, CDCl3) δ -
62.75.
4.18. 1-Methyl-3-(phenylthio)-1H-indole [3p] [100]
1
White solid, mp 116.7-118.5 oC; H NMR (400 MHz, CDCl3)
δ 7.66 (d, J = 8.0 Hz, 1H), 7.41-7.31 (m, 2H), 7.21-7.14 (m, 3H),
7.13-7.10 (m, 4H), 3.80 (s, 3H); 13C NMR (101 MHz, CDCl3) δ
138.63, 135.96, 129.32, 128.79, 127.53, 126.72, 126.32, 124.12,
121.20, 120.52, 110.32, 31.25.
4.27. 3-((4-(Trifluoromethoxy)phenyl)thio)-1H-indole [3y] [85]
4.19. 3-(P-tolylthio)-1H-indole [3q] [94]

6
Tetrahedron
o
1
Pale yellow solid, mp 122.3-125.1 C; H NMR (400 MHz,
117.72, 116.26, 116.04, 108.57, 34.12. HRMS (ESI-TOF) m/z
CDCl3) δ 8.49 (s, 1H), 7.59 (d, J = 8.0 Hz, 1H), 7.50-7.41 (m,
2H), 7.31-7.25 (m, 1H), 7.21-7.15 (m, 1H), 7.08 (d, J = 9.2 Hz,
2H), 6.99 (d, J = 8.4 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ
146.75, 146.73, 138.25, 136.66, 131.01, 128.95, 127.01, 123.36,
121.60, 121.59, 121.22, 119.58, 111.85, 102.35. 19F NMR (376
MHz, CDCl3) δ -62.17.
calculated for C11H11FNS+ (M + H)+ 208.0591, found 208.0587.
4.35. 2-((4-Chlorophenyl)thio)-1-methyl-1H-pyrrole[4g][107]
Pale yellow liquid; 1H NMR (400 MHz, CDCl3): δ 7.16 (d, J =
8.8 Hz, 2H), 6.92–6.82 (m, 3H), 6.56 (dd, J = 3.6, 1.6 Hz, 1H),
6.22 (dd, J = 3.6, 2.8 Hz, 1H), 3.54 (s, 3H). 13C NMR (101 MHz,
CDCl3): δ 137.82, 131.14, 129.15, 126.91, 126.39, 119.91,
116.81, 108.69, 77.16, 34.12.
4.28. 4-((1H-indol-3-yl)thio)benzonitrile [3z] [103]
White solid, mp 165.9-166.7 oC; H NMR (400 MHz, CDCl3)
1
4.36. 2-((4-Bromophenyl)thio)-1-methyl-1H-pyrrole[4h]
δ 8.70 (s, 1H), 7.56-7.45 (m, 3H), 7.38 (d, J = 8.6 Hz, 2H), 7.30
(t, J = 7.6 Hz, 1H), 7.18 (t, J = 7.6 Hz, 1H), 7.09 (d, J = 8.8 Hz,
2H); 13C NMR (101 MHz, CDCl3) δ 147.31, 136.70, 132.24,
131.36, 128.63, 125.54, 123.55, 121.42, 119.34, 119.27, 112.04,
107.64, 100.27.
Pale yellow liquid; 1H NMR (400 MHz, CDCl3): δ 7.31 (d, J =
8.8 Hz, 2H), 6.89 (t, J = 2.2 Hz, 1H), 6.81 (d, J = 8.8 Hz, 2H),
6.56 (dd, J = 4.0, 2.0 Hz, 1H), 6.23 (t, J = 3.2 Hz, 1H), 3.55 (s,
3H). 13C NMR (101 MHz, CDCl3): δ 138.56, 132.04, 127.20,
126.43, 119.95, 118.91, 116.64, 108.71, 77.16, 34.12. HRMS
(ESI-TOF) m/z calculated for C11H10BrNNaS+ (M + Na)+
289.9610, found 289.9616.
4.29. 3-(m-Tolylthio)-1H-indole [4a] [106]
White solid, mp 125.1-125.5 oC; H NMR (400 MHz, CDCl3)
1
δ 8.37 (s, 1H), 7.62 (d, J = 8.0 Hz, 1H), 7.49-7.40 (m, 2H), 7.25
(s, 1H), 7.19-7.14 (m, 1H), 7.03 (t, J = 7.6 Hz, 1H), 6.98 (s, 1H),
6.91-6.83 (m, 2H), 2.22 (s, 3H); 13C NMR (101 MHz, CDCl3) δ
139.07, 138.59, 136.59, 130.77, 129.30, 128.71, 126.60, 125.90,
123.14, 123.12, 120.98, 119.83, 111.67, 103.07, 21.50.
4.37. 2-((3-Bromophenyl)thio)-1-methyl-1H-pyrrole[4i]
1
Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 7.22–7.16
(m, 1H), 7.09–7.02 (m, 2H), 6.92–6.82 (m, 2H), 6.57 (dd, J = 3.6,
1.6 Hz, 1H), 6.23 (dd, J = 3.6, 2.8 Hz, 1H), 3.55 (s, 3H). 13C
NMR (101 MHz, CDCl3): δ 141.82, 130.36, 128.36, 128.08,
126.59, 124.07, 123.23, 120.17, 116.13, 108.80, 77.16, 34.15.
HRMS (ESI-TOF) m/z calculated for C11H10BrNNaS+ (M + Na)+
289.9610, found 289.9615.
4.30. 3-((3-(Trifluoromethyl)phenyl)thio)-1H-indole [4b] [94]
1
White solid, mp 107.5-108.8 oC; H NMR (400 MHz, CDCl3)
δ 8.42 (s, 1H), 7.49 (d, J = 7.9 Hz, 1H), 7.38 (d, J = 2.6 Hz, 1H),
7.37-7.29 (m, 2H), 7.22-7.16 (m, 2H), 7.13-7.05 (m, 3H); 13C
NMR (101 MHz, CDCl3) δ 141.11, 136.66, 131.18, 129.16,
128.90, 128.84, 123.39, 122.43, 122.38, 121.62, 121.58, 121.26,
119.46, 111.91, 101.51.
4.38. 1-Methyl-2-((3-(trifluoromethyl)phenyl)thio)-1H-pyrrole[4j]
1
Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 7.37–7.27
(m, 2H), 7.22 (s, 1H), 7.05 (d, J = 7.2 Hz, 1H), 6.92 (dd, J = 2.4,
1.6 Hz, 1H), 6.59 (dd, J = 3.6, 1.6 Hz, 1H), 6.25 (dd, J = 3.6, 2.8
Hz, 1H), 3.56 (s, 3H). 13C NMR (101 MHz, CDCl3): δ 141.14,
129.46, 128.58, 128.57, 126.72, 122.11, 122.07, 122.06, 122.03,
122.02, 121.98, 120.31, 115.84, 108.94, 77.16, 34.11. HRMS
(ESI-TOF) m/z calculated for C12H10F3NNaS+ (M + Na)+
280.0378, found 280.0379.
4.31. 3-((3-Bromophenyl)thio)-1H-indole [4c] [94]
1
White solid, mp 117.8-118.8 oC; H NMR (400 MHz, CDCl3)
δ 8.34 (s, 1H), 7.58 (d, J = 7.6 Hz, 1H), 7.41 (d, J = 2.8 Hz, 1H),
7.40 (d, J = 8.4 Hz, 1H), 7.27-7.21 (m, 2H), 7.20-7.11 (m, 2H),
7.03-6.92 (m, 2H); 13C NMR (101 MHz, CDCl3) δ 141.96,
136.56, 131.11, 130.12, 128.89, 128.31, 127.94, 124.42, 123.33,
123.29, 122.94, 121.22, 119.52, 111.84, 101.77.
4.39. 1-Methyl-2-(naphthalen-2-ylthio)-1H-pyrrole[4k][107]
1
4.32. 3-(Naphthalen-2-ylthio)-1H-indole [4d] [94]
Colorless liquid; H NMR (400 MHz, CDCl3): δ 7.74 (d, J =
8.0 Hz, 1H), 7.69 (d, J = 8.4 Hz, 1H), 7.64 (d, J = 8.0 Hz, 1H),
7.45–7.35 (m, 2H), 7.33 (d, J = 1.6 Hz, 1H), 7.13 (dd, J = 8.8, 2.0
Hz, 1H), 6.92 (t, J = 2.2 Hz, 1H), 6.63 (dd, J = 3.6, 1.6 Hz, 1H),
6.27 (dd, J = 3.6, 2.8 Hz, 1H), 3.57 (s, 3H). 13C NMR (101 MHz,
CDCl3): δ 136.66, 133.95, 131.60, 128.72, 127.86, 127.12,
126.66, 126.26, 125.45, 124.34, 123.52, 119.83, 117.31, 108.61,
77.16, 34.21.
1
White solid, mp 188.2-188.6 oC; H NMR (400 MHz, CDCl3)
δ 8.43 (s, 1H), 7.71 (d, J = 7.2 Hz, 1H), 7.63 (t, J = 8.4 Hz, 2H),
7.55 (dd, J = 7.6, 5.0 Hz, 2H), 7.50-7.44 (m, 2H), 7.39-7.32 (m,
2H), 7.30-7.25 (m, 2H), 7.14 (t, J = 7.4 Hz, 1H); 13C NMR (101
MHz, CDCl3) δ 136.84, 136.68, 133.89, 131.47, 130.83, 129.25,
128.38, 127.81, 127.05, 126.46, 125.18, 124.91, 123.67, 123.23,
121.10, 119.85, 111.73, 102.99.
4.40. 1-Methyl-2-((4-nitrophenyl)thio)-1H-pyrrole[4l]
4.33. 3-((2,5-Dimethylphenyl)thio)-1H-indole [4e] [45]
o
1
Pale yellow solid, mp 82.6-83.4 C H NMR (400 MHz,
CDCl3): δ 8.06 (d, J =8.8 Hz, 2H), 7.00 (d, J =8.8 Hz, 2H), 6.98
(dd, J = 2.8, 2.0 Hz, 1H), 6.61 (dd, J = 3.6, 1.6 Hz, 1H), 6.29 (dd,
J = 3.6, 2.8 Hz, 1H), 3.58 (s, 3H). 13C NMR (101 MHz, CDCl3):
δ 149.62, 145.40, 127.17, 124.99, 124.19, 120.57, 114.54,
109.22, 77.16, 34.11. HRMS (ESI-TOF) m/z calculated for
C11H11N2O2S+ (M + H)+ 235.0536, found 235.0541.
o
1
Pale yellow solid, mp 135.8-136.6 C; H NMR (400 MHz,
CDCl3) δ 8.43 (s, 1H), 7.60 (d, J = 8.0 Hz, 1H), 7.49-7.41 (m,
2H), 7.30-7.24 (m, 2H), 7.19-7.13 (m, 1H), 7.01 (d, J = 7.6 Hz,
1H), 6.78 (d, J = 7.6 Hz, 1H), 6.57 (s, 1H), 2.45 (s, 3H), 2.04 (s,
3H); 13C NMR (101 MHz, CDCl3) δ 137.87, 136.66, 135.95,
131.64, 130.80, 129.88, 129.46, 126.10, 125.60, 123.09, 120.94,
119.88, 111.66, 102.73, 21.20, 19.62.
4.41. 4-((1-Methyl-1H-pyrrol-2-yl)thio)benzonitrile[4m]
4.34. 2-((4-Fluorophenyl)thio)-1-methyl-1H-pyrrole[4f]
Pale yellow liquid; 1H NMR (400 MHz, CDCl3): δ 7.46 (d, J =
8.4 Hz, 2H), 7.01–6.91 (m, 3H), 6.58 (dd, J = 3.6, 1.6 Hz, 1H),
6.27 (dd, J = 3.6, 2.8 Hz, 1H), 3.56 (s, 3H). 13C NMR (101 MHz,
CDCl3): δ 147.02, 132.48, 127.01, 125.28, 120.49, 118.92,
114.66, 109.10, 108.40, 34.07. HRMS (ESI-TOF) m/z calculated
for C12H11N2S+ (M + H)+ 215.0637, found 215.0639.
Pale yellow liquid; 1H NMR (400 MHz, CDCl3): δ 6.99–6.89
(m, 4H), 6.88–6.84 (m, 1H), 6.56 (dd, J = 3.6, 1.6 Hz, 1H), 6.21
(t, J = 7.6 Hz, 1H), 3.55 (s, 3H). 13C NMR (101 MHz, CDCl3): δ
162.40, 159.97, 133.99, 133.95, 127.70, 127.62, 126.20, 119.63,

7
4.42. 2-((4-Nitrophenyl)thio)-1H-pyrrole [4n][108]
We gratefully acknowledge financial support of this work by
the National Natural Science Foundation of China (No.
21563025) and the Shihezi University (No. CXRC201602).
Yellow solid, mp 85.7-86.1 oC;1H NMR (400 MHz, CDCl3): δ
8.49 (s, 1H), 7.99 (d, J = 9.2 Hz, 2H), 7.07–7.03 (m, 1H), 7.01 (d,
J = 9.2 Hz, 2H), 6.66–6.58 (m, 1H), 6.38 (q, J = 3.0 Hz, 1H). 13
C
References and notes
NMR (101 MHz, CDCl3): δ 149.93, 145.23, 124.99, 124.06,
123.16, 119.85, 112.51, 111.16.
1. A. Mishra, C.Q. Ma, P. Bauerle, Chem. Rev., 2009, 1091,
141−1276.
2. K. Takimiya, I. Osaka, T. Mori, M. Nakano, Acc. Chem. Res.,
2014, 47, 1493−1502.
3. G. Qiu, K. Zhou, J. Wu, Chem. Commun., 2018, 54, 12561-12569.
4. C. Shen, P. Zhang, Q. Sun, S. Bai, T.A. Hor, X. Liu, Chem. Soc.
Rev. 2015, 44, 291−314.
5. C. F. Lee, Y. C. Liu, S. S. Badsara, Chem. -Asian J., 2014, 9, 706-
722.
6. F. Hu, W. Gao, H. Chang, X. Li, W. Wei, Chin. J. Org.
Chem. 2015, 35, 1848−1860.
7. Z. Qiao, X. Jiang, Org. Biomol. Chem., 2017, 15, 1942−1946.
8. C. Liu, D. Liu, A. Lei, Acc. Chem. Res., 2014, 47, 3459−3470.
9. F. Sun, X. Liu, X. Chen, C. Qian, X. Ge, Chin. J. Org.
Chem., 2017, 37, 2211−2220.
4.43. 2-(Naphthalen-2-ylthio)-1H-pyrrole[4o]
1
Colorless liquid; H NMR (400 MHz, CDCl3): δ 8.31 (s, 1H),
7.74 (d, J = 8.0 Hz, 1H), 7.68 (d, J = 8.4 Hz, 1H), 7.63 (d, J = 8.0
Hz, 1H), 7.45–7.34 (m, 3H), 7.16 (dd, J = 8.4, 2.0 Hz, 1H), 6.99–
6.92 (m, 1H), 6.67–6.59 (m, 1H), 6.35 (q, J = 3.0 Hz, 1H). 13C
NMR (101 MHz, CDCl3): δ 136.64, 133.85, 131.64, 128.69,
127.84, 127.16, 126.69, 125.56, 124.56, 123.92, 122.06, 118.87,
110.63. HRMS (ESI-TOF) m/z calculated for C14H12NS+ (M +
H)+ 226.0685, found 226.0686.
4.44. 2-((4-Bromophenyl)thio)-1H-pyrrole[4p]
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1
Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 8.27 (s,
1H), 7.30 (d, J = 8.8 Hz, 2H), 6.96–6.92 (m, 1H), 6.86 (d, J = 8.4
Hz, 2H), 6.59–6.53 (m, 1H), 6.32 (q, J = 3.0 Hz, 1H). 13C NMR
(101 MHz, CDCl3): δ 138.59, 131.98, 127.44, 122.26, 119.11,
119.09, 114.94, 110.75. HRMS (ESI-TOF) m/z calculated for
C10H18BrNNaS+ (M + Na)+ 275.9453, found 275.9453.
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4.45. 2-((3-Bromophenyl)thio)-1H-pyrrole[4q]
1
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Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 8.28 (s,
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275.9453, found 275.9448.
4.46. 2-Methyl-5-(p-tolylthio)-1H-pyrrole[4r]
1
Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 7.89 (s,
1H), 7.01 (d, J = 8.0 Hz, 2H), 6.96 (d, J = 8.4 Hz, 2H), 6.43 (t, J
= 3.0 Hz, 1H), 5.99–5.90 (m, 1H), 2.26 (s, 3H), 2.24 (s, 3H). 13C
NMR (101 MHz, CDCl3): δ 135.98, 135.27, 132.03, 129.75,
126.23, 119.21, 114.01, 108.36, 77.16, 20.98, 13.39. HRMS
(ESI-TOF) m/z calculated for C12H14NS+ (M + H)+ 204.0841,
found 204.0839.
4.47. 2-Methyl-5-((4-nitrophenyl)thio)-1H-pyrrole[4s]
Yellow solid, mp 76.5-76.9 oC;1H NMR (400 MHz, CDCl3): δ
8.18 (s, 1H), 7.98 (d, J = 8.8 Hz, 2H), 7.02 (d, J = 8.8 Hz, 2H),
6.49 (t, J = 3.0 Hz, 1H), 6.05 (t, J = 2.6 Hz, 1H), 2.32 (s, 3H). 13
C
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4.48. 2-Methyl-5-(naphthalen-2-ylthio)-1H-pyrrole[4t]
1
Pale yellow liquid; H NMR (400 MHz, CDCl3): δ 7.97 (s,
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9

Highlights
• With readily accessible and free of unpleasant odor ethyl arylsulfinates as
sulfur reagents, the metal-free-catalyzed direct sulfenylation of N-heteroarenes
has been developed.
• 3-Arylthio-indoles and 2-arylthio-pyrroles derivatives were obtained in
moderate to excellent yields, even on gram scale.
• The reaction was general for a broad scope of substrates and demonstrated
good tolerance to a variety of functional groups.