Assembly of 3-Sulfenylbenzofurans and 3-Sulfenylindoles by Palladium-Catalyzed Cascade Annulation/Arylthiolation Reaction

Article abstract of DOI:10.1021/acs.joc.6b00162

A novel and efficient palladium-catalyzed cascade annulation/arylthiolation reaction has been developed to afford functionalized 3-sulfenylbenzofuran and 3-sulfenylindole derivatives in moderate to good yields from readily available 2-alkynylphenols and 2

Full text of DOI:10.1021/acs.joc.6b00162

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Article
Assembly of 3-Sulfenylbenzofurans and 3-Sulfenylindoles by
Palladium-Catalyzed Cascade Annulation/Arylthiolation Reaction
Jianxiao Li, Chunsheng Li, Shaorong Yang, Yanni An, Wanqing Wu, and Huanfeng Jiang
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.6b00162 • Publication Date (Web): 15 Mar 2016
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Assembly of 3-Sulfenylbenzofurans and 3-Sulfenylindoles by
Palladium-Catalyzed Cascade Annulation/Arylthiolation
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Reaction
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Jianxiao Li,† Chunsheng Li,† Shaorong Yang,† Yanni An,† Wanqing Wu,*, †, ‡ and Huanfeng
†
Jiang*,
†
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
‡
State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
Fax: (+86) 20ꢀ8711ꢀ2906; Eꢀmail: cewuwq@scut.edu.cn, jianghf@scut.edu.cn
Abstract: A novel and efficient palladiumꢀcatalyzed cascade annulation/arylthiolation
reaction has been developed to afford functionalized 3ꢀsulfenylbenzofuran and
3ꢀsulfenylindole derivatives in moderate to good yields from readily available
2ꢀalkynylphenols and 2ꢀalkynylamines in ionic liquids. This protocol provides a
valuable synthetic tool for the assembly of a wide range of 3ꢀsulfenylbenzofuran and
3ꢀsulfenylindole derivatives with high atomꢀ and stepꢀeconomy and exceptional
functional group tolerance. Moreover, the employment of ionic liquids under mild
reaction conditions makes this transformation green and practical. Furthermore, this
approach enriched current C–S bond formation chemistry, making a valuable and
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practical method in synthetic and medicinal chemistry.
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INTRODUCTION
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The development of general and efficient methods for assembly of new chemical
bonds is fundamental and vibrant fields in both academic and industrial process.1
Prominently, transition metalꢀcatalyzed transformations have emerged as a powerful
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tool for the efficient construction of carbon
become the most attractive and versatile methods in contemporary organic synthesis.2
In this regard, as one of the most important carbon heteroatom bonds in organic
chemistry, C S bonds are frequently found in many important pharmaceuticals and
biologically active natural compounds.3 In recent years, many representative methods
have been developed for constructing C S bonds. Generically, three strategies are
–heteroatom bonds and, hence, have
–
–
–
typically employed: (i) coupling of vinyl/aryl halides with sulfenylating sources, such
as thiols, sulfonyl chlorides, disulfides and other activated sulfurating reagents;4 (ii)
coupling of alkylꢀ and aryllithium or Grignard reagents with diphenyldisulfides,
thiosulfonates and sulfur;5 (iii) direct arylthiolation of C
–H bonds with sulfurating
reagents.6 Despite the significances, all these elegant developments suffer from
certain limitations such as prefunctionalized reactants, stringent reaction conditions or
toxic and unstable sulfur sources, which lower the synthetic efficiency and generality.
As a consequence, the development of efficient and atom economical synthetic
methods for the rapid and straightforward construction of C–S bonds is still highly
desirable.
In addition, among the family of benzofurans, 2,3ꢀdifunctionalized benzofurans
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are attractive synthetic targets because of their remarkable biological activities and
potentiality of being pharmaceutical,7 prompting development of many efficient
synthetic methods for constructing this scaffold.8 However, the straightforward
synthesis of 2ꢀsubstituted 3ꢀsulfenylbenzofurans from readily accessible starting
materials has been scarcely explored. Recent achievements for the construction of
3ꢀsulfenylbenzofuran scaffold mainly include: (i) electrophilic cyclization of
2ꢀalkynylphenol derivatives with sulfurating reagents (Scheme 1a);9 (ii)
metalꢀinvolved cascade annulation of 2ꢀalkynylphenol derivatives with disulfides
(Scheme 1b);10 (iii) I2ꢀmediated cyclization of 2ꢀalkynylanisoles with sulfurating
reagents (Scheme 1c).11 Nevertheless, these approaches require foulsmelling, toxic
and unstable sulfur sources as starting materials. From the view point of synthetic
simplicity as well as new practical and environmentally benign process, the synthesis
of 3ꢀsulfenylbenzofurans via a transition metalꢀcatalyzed cascade annulation reaction
would be an ideal strategy. More recently, we report an efficient and ecofriendly
method for the construction of 2,3ꢀdifunctionalized benzofuran derivatives in
moderate to good yields from readily available 2ꢀalkynylphenols in ionic liquids.12
Inspired by the aforementioned background and our longstanding interest in
Pdꢀcatalyzed crossꢀcoupling reactions in ionic liquids,13 herein, we disclose an
efficient and concise route for the synthesis of 3ꢀsulfenylbenzofurans and
3ꢀsulfenylindoles via nucleopalladation triggering intermolecular cascade reaction in
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ionic liquids (Scheme 1d).
Scheme 1. Representative strategies for synthesis of 3ꢀsulfenylbenzofurans
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RESULTS AND DISCUSSION
To begin our investigation, 2ꢀ(phenylethynyl)phenol (1a), phenylboronic acid (2a)
and elemental sulfur (S8) were selected as a model system to screen the optimal
conditions, and the results are summarized in Table 1. First, with the combination of
Pd(OAc)2 (5 mol %), CuI (1 equiv), Phen (1.1 equiv), BQ (2 equiv) and K2CO3 (2
equiv) in [Bmim]Cl (1 mL)14 at 80 °C for 8 h, the desired sulfenylation product 3aa
was obtained in 27% GC yield (Table 1, entry 1). Further exploration of oxidants in
the model reaction indicated that Ag2CO3 was superior to others (entries 1ꢀ4). Among
the examination of palladium catalysts, other palladium catalysts, including Pd(OAc)2,
PdI2, PdCl2, Pd(PhCN)2Cl2 and [Pd(ŋ3ꢀC3H5)Cl]2, were inferior to Pd(TFA)2 (entries
4ꢀ9). Subsequently, different copper salts were examined, including CuCl, CuBr,
CuCN and CuI, and CuI was the most effective catalyst for this transformation (entry
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5). Except for K3PO4, other bases, including K2CO3, KF, Cs2CO3, Et3N and CsF,
showed low efficiencies (entries 5, 14ꢀ18). Finally, the reaction without the use of a
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metal salt was found to be ineffective (entries 20 and 21).
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Table 1. Optimization of the reaction conditionsa
Entry
1
Catalyst
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(TFA)2
PdI2
CuX
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
ꢀ
Oxidant
BQ
Base
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K3PO4
KF
Conversion (%)b
27
trace
46
56
78
23
64
34
9
2
DDQ
3
AgNO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
Ag2CO3
4
5
6
7
PdCl2
8
Pd(PhCN)2Cl2
[Pd(ŋ3ꢀC3H5)Cl]2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
Pd(TFA)2
ꢀ
9
10
11
12
13
14
15
16
17
18
19c
20
21
ꢀ
CuCl
CuBr
CuCN
CuI
CuI
CuI
CuI
CuI
CuI
CuI
ꢀ
27
38
trace
95(90)
65
79
28
69
94
ꢀ
Cs2CO3
Et3N
CsF
K3PO4
K3PO4
K3PO4
Pd(TFA)2
ꢀ
a Reactions were performed with 1a (0.10 mmol), 2a (0.15 mmol), S8 (0.30 mmol), catalyst (5
mol %), CuX (0.20 mmol), Phen (1,10ꢀphenanthroline, 0.22 mmol), oxidant (0.2 mmol), base (0.2
mmol), [Bmim]Cl (1ꢀbutylꢀ3ꢀmethylimidazolium chloride, 1 mL) at 80 oC for 8 h. BQ =
b
1,4ꢀbenzoquinone; Determined by GC using dodecane as the internal standard; The value in
parentheses is the yield of isolated product; c At 100 oC.
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Scheme 2. Cascade annulation/arylthiolation of 2a with various 2ꢀalkynylphenolsa
R1
SPh
Pd(TFA)2 (5 mol%), CuI (2 equiv)
Phen (2.2 equiv)
R2
R2
R1
PhB(OH)2
S8
K3PO4 (2 equiv), Ag2CO3 (2 equiv)
[Bmim]Cl (1 mL), N2, 80 o
O
OH
2a
C
3
1
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SPh
SPh
SPh
nPr
Et
O
O
R
O
3al, 78%
3am, 75%
R = H, 3aa, 90%;
SPh
SPh
SPh
R = 4-Et, 3ab, 91%;
R = 4-nPr, 3ac, 88%;
R = 4-tBu, 3ad, 85%;
R = 4-nC5H11, 3ae, 86%;
R = 4-nC6H13, 3af, 84%;
R = 4-OMe, 3ag, 76%;
R = 4-F, 3ah, 79%;
n
Ph
O
S
O
O
3an, 68%
n = 1, 3ao, 72%;
n = 2, 3ap, 74%;
n = 3, 3aq, 70%;
Cl
3ar, 74%
SPh
SPh
R
R = 4-Cl, 3ai, 80%;
R = F, 3au, 80%;
R = 2,4-dimethyl, 3aj, 83%;
R = 3,4-dichloro, 3ak, 73%;
R = Cl, 3av, 82%;
R = Br, 3aw, 77%;
R = NO2, 3ax, 63%;
O
O
R
R = Me, 3as, 93%;
R = COOMe, 3at, 67%;
a Reaction conditions:
1 (0.20 mmol), 2a (0.4 mmol), S8 (0.60 mmol), Pd(TFA)2 (5 mol %),
CuI (0.40 mmol), Phen (0.44 mmol), Ag2CO3 (0.4 mmol), K3PO4 (0.4 mmol), [Bmim]Cl (1
mL) at 80 oC for 8 h; Yields referred to isolated yield.
After establishing the optimized reaction conditions, the generality and substrate
scope of 2ꢀalkynylphenol derivatives were investigated (Scheme 2). Gratifyingly, both
electronꢀdonating and electronꢀwithdrawing substituents on the phenyl ring afforded
the desired products in good yields (3aaꢀ3am). Additionally, this transformation could
be successfully extended to 2,4ꢀ and 3,4ꢀdisubstituted 2ꢀalkynylphenols, furnishing
the corresponding 3ꢀsulfenylbenzofuran derivatives 3aj and 3ak in 83% and 73%
yields,
respectively.
More
bulky
substrates
(1l)
such
as
2ꢀ((4'ꢀpropylꢀ[1,1'ꢀbiphenyl]ꢀ4ꢀyl)ethynyl)phenol
and
2ꢀ((4ꢀ(4ꢀethylcyclohexyl)phenyl)ethynyl)phenol (1m) also efficiently reacted with 2a
and gave the products 3al and 3am in 78% and 75% yields, respectively. Importantly,
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impressive feature of the current cascade annulation/arylthiolation reaction is its high
tolerance for functional groups. For instance, the 2ꢀalkynylphenols containing thienyl
group underwent the cascade reaction to give the corresponding product 3an in 68%
yield. Notably, 2ꢀalkynylphenols 1 with alkyl groups attached on the triple bond
proceeded smoothly to give the products 3 in moderate to good yields (3aoꢀ3ar).
Delightfully, various substituted 2ꢀalkynylphenols with electronꢀdonating groups (Me)
and weakly or moderately electronꢀwithdrawing groups (F, Cl, Br, COOMe, NO2)
afforded the corresponding 3ꢀsulfenylbenzofuran derivatives 3asꢀ3ax in moderate to
excellent yields.
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Scheme 3. Cascade annulation/arylthiolation of 1a with various arylboronic acid
derivativesa
a
Reaction conditions: 1a (0.20 mmol), 2 (0.4 mmol), S8 (0.60 mmol), Pd(TFA)2 (5 mol%), CuI
(0.40 mmol), Phen (0.44 mmol), Ag2CO3 (0.4 mmol), K3PO4 (0.4 mmol), [Bmim]Cl (1 mL) at 80
oC for 8 h; Yields referred to isolated yield.
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Subsequently, to further demonstrate the synthetic potential of this method,
various arylboronic acid derivatives were introduced to this cascade reaction (Scheme
3). Various substituents of arylboronic acid, such as methyl, methoxyl, halo, and nitro
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groups were tolerated well, allowing the generation of
a
range of
3ꢀsulfenylbenzofurans derivatives in moderate yields (3baꢀ3bh).
Scheme 4. Substrate scope of 2ꢀalkynyl arylaminesa
Ph
S
Ph
Pd(TFA)2 (5 mol%), CuI (2 equiv)
Phen (2.2 equiv)
R4
R4
PhB(OH)2
S8
Ph
K3PO4 (2 equiv), Ag2CO3 (2 equiv)
[Bmim]Cl (1 mL), N2, 80 oC
N
2a
NH2
X
H
5
X = C, N
4
SPh
SPh
SPh
SPh
Me
MeO
Ph
Ph
Ph
Ph
N
N
H
N
N
Me
H
H
H
5ad, 77%
SPh
5aa, 90%
5ab, 87%
SPh
5ac, 89%
SPh
SPh
Me
Br
Cl
F
Ph
Ph
Ph
Ph
N
N
H
N
H
N
H
Cl
H
Me
Cl
5ae, 83%
SPh
5ag, 84%
5af, 81%
5ah, 71%
SPh
SPh
SPh
F3C
MeOOC
Ph
Ph
Ph
Ph
N
H
N
H
N
N
N
H
H
5ai, 80%
5aj, 70%
5ak, 64%
5al, trace
a
Reaction conditions: 4 (0.20 mmol), 2a (0.4 mmol), S8 (0.60 mmol), Pd(TFA)2 (5 mol %), CuI
(0.40 mmol), Phen (0.44 mmol), Ag2CO3 (0.4 mmol), K3PO4 (0.4 mmol), [Bmim]Cl (1 mL) at 80
oC for 8 h; Yields referred to isolated yield.
As mentioned previously, 3ꢀsulfenylindoles could be synthesized by
2ꢀalkynylanilines with disulfides.15 Gratifyingly, 3ꢀsulfenylindoles also could be
constructed via the cascade annulation/arylthiolation of 2ꢀ(phenylethynyl)aniline
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derivatives with phenylboronic acid 2a. As illustrated in Scheme 4, anilines with
electronꢀrich substituents (Me, OMe) or electronꢀpoor substituents (F, Cl, Br, CF3,
COOMe) all gave the desired products in satisfactory yields (5aaꢀ5ak). Moreover,
substitution position of the aromatic ring just had a slight impact (5ab, 5ac and 5ae).
These results showed that this new transformation was tolerant towards the electronic
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and
steric
effects
of
the
aromatic
ring.
However,
when
3ꢀ(phenylethynyl)pyridinꢀ2ꢀamine (4l) was subjected to the standard reaction
conditions, only trace amount of the desired product 5al was detected by GCꢀMS.
Scheme 5. Substrate scope of 2ꢀalkynyl arylaminesa
R5
SPh
Pd(TFA)2 (5 mol%), CuI (2 equiv)
Phen (2.2 equiv)
R5
PhB(OH)2
S8
K3PO4 (2 equiv), Ag2CO3 (2 equiv)
[Bmim]Cl (1 mL), N2, 80 oC
N
H
2a
NH2
5
4
SPh
SPh
SPh
SPh
R
N
H
N
N
N
H
H
H
5bf, 85%
5be, 80%
5bg, 83%
R = Me, 5ba, 89%;
R = OMe, 5bb, 83%;
R = Cl, 5bc, 80%;
R = NO2, 5bd, trace;
SPh
SPh
SPh
nC3H7
N
H
N
H
N
H
5bh, 80%
5bj, 89%
5bi, 75%
SPh
SPh
SPh
SPh
nC4H9
nC8H17
N
N
H
N
H
N
H
H
5bk, 84%
5bl, 83%
5bm, 87%
5bn, 83%
SPh
SPh
SPh
S
N
N
H
CN
N
H
H
5bo, 79%
5bp, 71%
5bq, 63%
a
Reaction conditions: 4 (0.20 mmol), 2a (0.4 mmol), S8 (0.60 mmol), Pd(TFA)2 (5 mol %), CuI
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(0.40 mmol), Phen (0.44 mmol), Ag2CO3 (0.4 mmol), K3PO4 (0.4 mmol), [Bmim]Cl (1 mL) at 80
oC for 8 h; Yields referred to isolated yield.
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To further explore the generality and scope of this method, a wide array of
2ꢀalkynylamines were examined, and the results are summarized in Scheme 5. A
range of functional groups on the arylalkynyl moiety, including pꢀMe, pꢀOMe and
pꢀCl was tolerated under the standard reaction conditions (5baꢀ5bc). Unfortunately,
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only
trace
desired
product
was
detected
by
GCꢀMS
when
2ꢀ((4ꢀnitrophenyl)ethynyl)aniline (4b) was used as substrate. Furthermore,
2ꢀalkynylamines 4 with alkyl groups attached on the triple bond also proceeded well
to give the products 5 in moderate to good yields (5beꢀ5bo). Gratifyingly, the
substrates containing threeꢀ, fiveꢀ or sixꢀmemberedꢀringꢀsubstituted 2ꢀalkynylamines
proceeded smoothly under the optimized conditions to afford the corresponding
products in high yields (5beꢀ5bi). It is noteworthy that with the carbon chain of alkyl
groups extended, the 3ꢀsulfenylindole derivatives 5bjꢀ5bo were successfully obtained
in good to excellent yields. Notably, 2ꢀalkynylamines containing vinyl or thienyl
groups were well tolerated, and afforded the desired products 5bp and 5bq in 71%
and 63% yields, respectively.
To extend the applicability of our reaction, we then evaluated the compatibility of
various arylboronic acids in this transformation (Scheme 6). Under the standard
reaction conditions, various arylboronic acid derivatives with pꢀMe, pꢀMeO, pꢀF, mꢀF,
oꢀF and pꢀCl substituents were explored. These functional groups were compatible
with the current procedure, and afforded the corresponding 3ꢀsulfenylindole
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derivatives 5caꢀ5cg in 71ꢀ88% yields. Unfortunately, the coupling reactions between
2ꢀ(phenylethynyl)aniline (4a) and furanꢀ2ꢀylboronic acid (2h) failed to give the
desired product.
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Scheme 6. Substrate scope of various arylboronic acid derivativesa
a
Reaction conditions: 4a (0.20 mmol), 2 (0.4 mmol), S8 (0.60 mmol), Pd(TFA)2 (5 mol %), CuI
(0.40 mmol), Phen (0.44 mmol), Ag2CO3 (0.4 mmol), K3PO4 (0.4 mmol), [Bmim]Cl (1 mL) at 80
oC for 8 h; Yields referred to isolated yield.
To investigate the mechanism of the cascade arylthiolation, several controlled
experiments were performed (Scheme 7). Under the standard conditions, the reaction
of 1a with 1,2ꢀdiphenyldisulfane (6) did not give the desired
2ꢀphenylꢀ3ꢀ(phenylthio)benzofuran
(3aa)
(Eq.
1).
Furthermore,
when
2ꢀphenylbenzofuran (7) and disulfide (6) were allowed to react under the standard
conditions, the same result was also obtained and no desired product was detected (Eq.
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2). In addition, the control experiment of
a
potential intermediate
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3ꢀchloroꢀ2ꢀphenylbenzofuran (8) with disulfide (6) also was investigated by following
the current procedure, and the result showed that no target product 3aa was observed
by GCꢀMS analysis (Eq. 3).10a All of these observations indicated that disulfide (6),
2ꢀphenylbenzofuran (7) and 3ꢀchloroꢀ2ꢀphenylbenzofuran (8) were not involved in
this chemical process. Finally, when 3ꢀchloroꢀ2ꢀphenylbenzofuran (8) was employed
to react with thiophenol (9) under the standard conditions, no reaction occurred at all,
which further suggested that the reaction did not proceed via a chlorocyclization
process (Eq. 4).
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Scheme 7. Control Experiments
Ph
SPh
standard conditions
S-S
(1)
Ph
Ph
Ph
Ph
6
O
OH
3aa
3aa
3aa
1a
SPh
H
standard conditions
S-S
6
(2)
Ph
Ph
Ph
Ph
Ph
O
O
7
SPh
Cl
standard conditions
standard conditions
S-S
6
(3)
(4)
Ph
Ph
Ph
Ph
O
O
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8
SPh
Cl
PhSH
O
3aa
9
O
On the basis of the above results and the reported mechanism, a tentative mechanism
12, 13
is proposed in Scheme 8. Initially, Pd complex is formed in situ in ionic liquids.
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Then, nucleopalladation of 2ꢀalkynylphenols or 2ꢀalkynylamines afforded vinyl
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palladium intermediate I.
Simultaneously, organocopper thiolate complex II is
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generated in situ from the reaction of elemental sulfur (S8) with aryl boronic acid in
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the presence of CuI complex.
Subsequently, intermediate I underwent the
transmetallation process with organocopper thiolate complex II to provide
intermediate III. Finally, a reductive elimination gives the target product. It is
noteworthy that a silver mirror reaction was observed after the reaction was finished.
18
Hence, the resulting palladium(0) is additionally oxidized to palladium(II) to
complete this catalytic cycle.
Scheme 8. Proposed mechanism
CONCLUSION
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In conclusion, we have successfully accomplished an attractive strategy for
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direct assembly of 3ꢀsulfenylbenzofurans and 3ꢀsulfenylindoles via
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palladium/copper
catalyzed
cascade
annulation/arylthiolation
of
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2ꢀalkynylphenols or 2ꢀalkynylamines with arylboronic acid and S8 in ionic
liquids. This observation provides a novel route for direct accessing
3ꢀsulfenylbenzofurans and 3ꢀsulfenylindoles in good to excellent yields and
good functional groups tolerance with high atom efficiency. Further
investigation of the reaction mechanism as well as the synthetic potential
applications of this protocol, is currently under way.
EXPERIMENTAL SECTION
General methods. Melting points were measured by a melting point instrument and
were uncorrected. 1H and 13C NMR spectra were recorded by using a 400 MHz NMR
spectrometer. The chemical shifts are referenced to signals at 7.24 and 77.0 ppm,
respectively, and chloroform is used as a solvent with TMS as the internal standard.
IR spectra were obtained either as potassium bromide pellets or as liquid films
between two potassium bromide pellets with an infrared spectrometer. GCꢀMS was
obtained using electron ionization. The data of HRMS was carried out on a
highꢀresolution mass spectrometer (LCMSꢀITꢀTOF). TLC was performed by using
commercially available 100ꢀ400 mesh silica gel plates (GF254). Unless otherwise
noted, all purchased chemicals were used without further purification. The
2ꢀalkynylphenols and 2ꢀalkynylamines were prepared according to the literature.19
General Procedure for Cascade Annulation/Arylthiolation
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Pd(TFA)2 (5 mol %) and [Bmim]Cl (1 mL) were combined in an Schlenk tube
equipped with a stirꢀbar and stirred at room temperature for 10 min. A balloon filled
with N2 was connected to the Schlenk tube via the side tube and purged 3 times. Then
1 (0.20 mmol), 2 (0.4 mmol), S8 (0.60 mmol), CuI (0.40 mmol), Phen (0.44 mmol),
Ag2CO3 (0.4 mmol) and K3PO4 (0.4 mmol) were quickly added to the tube under N2
atmosphere and stirred at 80 oC for 8 h. After the reaction was completed, the N2 gas
was released carefully and the reaction was quenched by water and extracted with
CH2Cl2 three times. The combined organic layers were dried over anhydrous Na2SO4
and evaporated under vacuum. The desired products were obtained in the
corresponding yields after purification by flash chromatography on silica gel with
hexanes/ethyl acetate. Compounds 3abꢀ3af, 3ah, 3ajꢀ3am, 3aoꢀ3ar, 3at, 3au, 3aw,
3ax, 3bc, 3bh, 5acꢀ5ak, 5bcꢀ5bp, 5cc, 5cd and 5cg are all new compounds.
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2-Phenyl-3-(phenylthio)benzofuran (3aa)10a : Yield: 90% (54.4 mg) as a white solid; mp = 64.3
ꢀ 65.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.23 (d, J = 8.0 Hz, 2H), 7.55 (d, J = 8.0 Hz, 1H), 7.50 ꢀ
7.38 (m, 4H), 7.32 (t, J = 7.6 Hz, 1H), 7.25 ꢀ 7.15 (m, 5H), 7.13ꢀ7.06 (m, 1H); 13C NMR (100
MHz, CDCl3) δ 157.5, 154.0, 136.2, 130.8, 129.8, 129.4, 129.1, 128.6, 127.4, 126.6, 125.6, 125.3,
123.5, 120.4, 111.4, 104.7 ppm; νmax(KBr)/cmꢀ1 3040, 2935, 1630, 1444, 1410, 1032, 687; MS (EI)
m/z 105, 165, 197, 225, 273, 302; HRMSꢀESI (m/z): calcd for C20H14NaOS, [M+Na]+: 325.0658,
found 325.0654.
2-(4-Ethylphenyl)-3-(phenylthio)benzofuran (3ab): Yield: 91% (60.1 mg) as a yellow solid; mp
= 69.8 ꢀ 70.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.14 (d, J = 8.0 Hz, 2H), 7.53 (d, J = 8.0 Hz, 1H),
7.47 (d, J = 7.6 Hz, 1H), 7.29 (dd, J = 17.6, 7.6 Hz, 3H), 7.22 ꢀ 7.13 (m, 5H), 7.12 ꢀ 7.04 (m, 1H),
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2.67 (q, J = 7.2 Hz, 2H), 1.24 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 157.9, 153.9,
145.9, 136.4, 131.0, 129.1, 128.2, 127.5, 127.3, 126.5, 125.5, 125.1, 123.4, 120.3, 111.3, 103.9,
28.8, 15.3 ppm; νmax(KBr)/cmꢀ1 3045, 2932, 1633, 1441, 1415, 1023, 683; MS (EI) m/z 133, 165,
193, 225, 268, 301, 330; HRMSꢀESI (m/z): calcd for C22H18NaOS, [M+Na]+: 353.0971, found
353.0977.
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3-(Phenylthio)-2-(4-propylphenyl)benzofuran (3ac) : Yield: 88% (60.5 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.14 (d, J = 8.0 Hz, 2H), 7.53 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 7.6 Hz,
1H), 7.30 (d, J = 7.2 Hz, 1H), 7.24 (d, J = 8.0 Hz, 2H), 7.21 ꢀ 7.13 (m, 5H), 7.10 ꢀ 7.03 (m, 1H),
2.60 (t, J = 7.6 Hz, 2H), 1.72 ꢀ 1.58 (m, 2H), 0.94 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
δ 158.0, 153.9, 144.4, 136.5, 131.0, 129.1, 128.7, 127.4, 127.3, 126.6, 125.5, 125.1, 123.4, 120.3,
111.3, 103.9, 38.0, 24.4, 13.9 ppm; νmax(KBr)/cmꢀ1 3048, 2933, 1631, 1445, 1408, 1022, 687; MS
(EI) m/z 105, 165, 178, 224, 282, 315, 344; HRMSꢀESI (m/z): calcd for C23H20NaOS, [M+Na]+:
367.1127, found 367.1135.
2-(4-(tert-Butyl)phenyl)-3-(phenylthio)benzofuran (3ad): Yield: 85% (60.8 mg) as a yellow
solid; mp = 108.9 ꢀ 110.3 °C; 1H NMR (400 MHz, CDCl3) δ 8.16 (d, J = 7.6 Hz, 2H), 7.55 (d, J =
8.0 Hz, 1H), 7.47 (d, J = 7.6 Hz, 3H), 7.32 (t, J = 7.6 Hz, 1H), 7.23 ꢀ 7.16 (m, 5H), 7.12 ꢀ 7.07 (m,
1H), 1.34 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 157.9, 153.9, 152.7, 136.4, 130.9, 129.0, 127.2,
127.0, 126.4, 125.6, 125.4, 125.0, 123.4, 120.3, 111.3, 103.9, 34.8, 31.2 ppm; νmax(KBr)/cmꢀ1 3050,
2936, 1638, 1446, 1412, 1029, 686; MS (EI) m/z 115, 156, 189, 234, 315, 343, 358; HRMSꢀESI
(m/z): calcd for C24H22NaOS, [M+Na]+: 381.1284, found 381.1289.
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2-(4-Pentylphenyl)-3-(phenylthio)benzofuran (3ae): Yield: 86% (63.9 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.14 (d, J = 7.2 Hz, 2H), 7.53 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 7.2 Hz,
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1H), 7.30 (d, J = 7.2 Hz, 1H), 7.24 (d, J = 7.6 Hz, 2H), 7.21 ꢀ 7.12 (m, 5H), 7.11 ꢀ 7.04 (m, 1H),
2.62 (t, J = 7.2 Hz, 2H), 1.69 ꢀ 1.56 (m, 2H), 1.39 ꢀ 1.27 (m, 4H), 0.88 (t, J = 7.2 Hz, 3H); 13C
NMR (100 MHz, CDCl3) δ 158.0, 154.0, 144.7, 136.5, 131.0, 129.1, 128.7, 127.4, 127.3, 126.5,
125.5, 125.1, 123.4, 120.3, 111.3, 103.9, 35.9, 31.5, 30.9, 22.6, 14.1 ppm; νmax(KBr)/cmꢀ1 3048,
2926, 1636, 1448, 1410, 1028, 684; MS (EI) m/z 105, 139, 165, 178, 282, 315, 340, 372;
HRMSꢀESI (m/z): calcd for C25H24NaOS, [M+Na]+: 395.1440, found 395.1447.
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2-(4-Hexylphenyl)-3-(phenylthio)benzofuran (3af): Yield: 84% (64.8 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.14 (d, J = 8.0 Hz, 2H), 7.53 (d, J = 8.4 Hz, 1H), 7.46 (d, J = 7.6 Hz,
1H), 7.30 (d, J = 7.2 Hz, 1H), 7.24 (d, J = 8.0 Hz, 2H), 7.22 ꢀ 7.12 (m, 5H), 7.11 ꢀ 7.04 (m, 1H),
2.62 (t, J = 7.6 Hz, 2H), 1.61 (dd, J = 13.6, 6.8 Hz, 2H), 1.35 ꢀ 1.25 (m, 6H), 0.87 (t, J = 7.2 Hz,
3H); 13C NMR (100 MHz, CDCl3) δ 158.0, 153.9, 144.7, 136.4, 131.0, 129.1, 128.7, 127.4, 127.3,
126.5, 125.5, 125.1, 123.4, 120.3, 111.3, 103.8, 35.9, 31.8, 31.2, 29.0, 22.6, 14.1 ppm;
ν
max(KBr)/cmꢀ1 3046, 2932, 1630, 1445, 1416, 1022, 684; MS (EI) m/z 105, 165, 224, 315, 354,
386; HRMSꢀESI (m/z): calcd for C26H26NaOS, [M+Na]+: 409.1597, found 409.1597.
2-(4-Methoxyphenyl)-3-(phenylthio)benzofuran (3ag)10a : Yield: 76% (50.5 mg) as a yellow
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solid; mp = 76.0 ꢀ 77.9 °C; H NMR (400 MHz, CDCl3) δ 8.17 (d, J = 8.8 Hz, 2H), 7.52 (d, J =
8.0 Hz, 1H), 7.46 (d, J = 7.6 Hz, 1H), 7.28 (t, J = 7.6 Hz, 1H), 7.21 ꢀ 7.14 (m, 5H), 7.11 ꢀ 7.04 (m,
1H), 6.94 (d, J = 8.8 Hz, 2H), 3.80 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 160.6, 157.9, 153.8,
136.5, 131.1, 129.1, 129.0, 126.4, 125.5, 124.9, 123.4, 122.5, 120.1, 114.1, 111.2, 102.7, 55.4 ppm;
νmax(KBr)/cmꢀ1 3048, 2938, 1636, 1442, 1411, 1028, 688; MS (EI) m/z 108, 152, 193, 227, 271,
317, 332; HRMSꢀESI (m/z): calcd for C21H16NaO2S, [M+Na]+: 355.0763, found 355.0770.
2-(4-Fluorophenyl)-3-(phenylthio)benzofuran (3ah): Yield: 79% (50.6 mg) as a white solid; mp
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= 68.5 ꢀ 69.6 °C; 1H NMR (400 MHz, CDCl3) δ 8.26 ꢀ 8.17 (m, 2H), 7.54 (d, J = 8.0 Hz, 1H), 7.48
(d, J = 7.6 Hz, 1H), 7.33 (t, J = 7.6 Hz, 1H), 7.24 ꢀ 7.16 (m, 5H), 7.12 (t, J = 8.0 Hz, 3H); 13C
NMR (100 MHz, CDCl3) δ 163.3 (d, J = 249.4 Hz), 156.6, 153.9, 136.0, 130.8, 129.4 (d, J = 8.0
Hz), 129.1, 126.5, 126.1 (d, J = 3.3 Hz), 125.7, 125.3, 123.6, 120.4, 115.7 (d, J = 21.6 Hz), 111.3,
104.4 ppm; νmax(KBr)/cmꢀ1 3049, 1628, 1437, 1402, 1028, 687; MS (EI) m/z 105, 165, 197, 215,
291, 320; HRMSꢀESI (m/z): calcd for C20H13FNaOS, [M+Na]+: 343.0563, found 343.0558.
2-(4-Chlorophenyl)-3-(phenylthio)benzofuran (3ai)11b : Yield: 80% (53.7 mg) as a white solid;
mp = 77.6 ꢀ 78.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.19 (d, J = 7.2 Hz, 2H), 7.55 (d, J = 8.4 Hz,
1H), 7.48 (d, J = 7.6 Hz, 1H), 7.41 (d, J = 7.2 Hz, 2H), 7.34 (t, J = 7.6 Hz, 1H), 7.23 ꢀ 7.16 (m,
5H), 7.14 ꢀ 7.08 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 156.3, 153.9, 135.8, 135.4, 130.7, 129.1,
128.9, 128.6, 128.3, 126.6, 125.7, 125.5, 123.6, 120.5, 111.4, 105.4 ppm; νmax(KBr)/cmꢀ1 3046,
2938, 1622, 1436, 1408, 1022, 680; MS (EI) m/z 105, 139, 163, 224, 268, 307, 336; HRMSꢀESI
(m/z): calcd for C20H13ClNaOS, [M+Na]+: 359.0268, found 359.0267.
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2-(2,4-Dimethylphenyl)-3-(phenylthio)benzofuran (3aj): Yield: 83% (54.8 mg) as a yellow oil;
1H NMR (400 MHz, CDCl3) δ 7.54 (d, J = 8.4 Hz, 1H), 7.44 (d, J = 7.6 Hz, 1H), 7.38 (d, J = 8.0
Hz, 1H), 7.33 (t, J = 7.6 Hz, 1H), 7.24 (d, J = 7.6 Hz, 1H), 7.21 ꢀ 7.08 (m, 6H), 7.05 (d, J = 7.6 Hz,
1H), 2.38 (s, 3H), 2.36 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 160.3, 154.5, 140.0, 138.0, 136.6,
131.5, 130.9, 129.7, 128.9, 126.6, 126.3, 126.0, 125.3, 124.8, 123.3, 120.4, 111.5, 106.3, 21.3,
20.5 ppm; νmax(KBr)/cmꢀ1 3043, 2935, 1626, 1438, 1408, 1360, 1030, 690; MS (EI) m/z 115, 165,
221, 269, 297, 330; HRMSꢀESI (m/z): calcd for C22H18NaOS, [M+Na]+: 353.0971, found
353.0973.
2-(3,4-Dichlorophenyl)-3-(phenylthio)benzofuran (3ak): Yield: 73% (54.0 mg) as a yellow
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solid; mp = 116.6 ꢀ 117.2 °C; 1H NMR (400 MHz, CDCl3) δ 8.34 (s, 1H), 8.12 (d, J = 8.4 Hz, 1H),
7.54 (d, J = 8.0 Hz, 1H), 7.47 (d, J = 8.0 Hz, 2H), 7.35 (t, J = 7.6 Hz, 1H), 7.23 ꢀ 7.16 (m, 5H),
7.15 ꢀ 7.08 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 154.5, 154.0, 135.4, 133.3, 133.0, 130.6,
129.7, 129.2, 128.9, 127.0, 126.3, 126.0, 125.9, 123.8, 120.7, 111.4, 106.8 ppm; νmax(KBr)/cmꢀ1
3036, 1627, 1442, 1410, 1026, 687; MS (EI) m/z 105, 163, 197, 225, 258, 302, 341, 370;
HRMSꢀESI (m/z): calcd for C20H12Cl2NaOS, [M+Na]+: 392.9878, found 392.9877.
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3-(Phenylthio)-2-(4'-propyl-[1,1'-biphenyl]-4-yl)benzofuran (3al): Yield: 78% (65.5 mg) as a
yellow solid; mp = 113.9 ꢀ 114.5 °C; 1H NMR (400 MHz, CDCl3) δ 8.31 (d, J = 8.4 Hz, 2H), 7.67
(d, J = 8.0 Hz, 2H), 7.55 (t, J = 8.0 Hz, 3H), 7.49 (d, J = 7.6 Hz, 1H), 7.34 (d, J = 7.6 Hz, 1H),
7.30 ꢀ 7.16 (m, 7H), 7.14 ꢀ 7.07 (m, 1H), 2.63 (t, J = 7.6 Hz, 2H), 1.84 ꢀ 1.58 (m, 2H), 0.97 (t, J =
7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 157.4, 154.0, 142.4, 142.0, 137.7, 136.3, 131.0, 129.1,
129.0, 128.4, 127.7, 127.0, 126.9, 126.6, 125.6, 125.3, 123.5, 120.4, 111.3, 104.7, 37.7, 24.5, 13.9
ppm; νmax(KBr)/cmꢀ1 3046, 2933, 1626, 1445, 1408, 1400, 1024, 688; HRMSꢀESI (m/z): calcd for
C29H24NaOS, [M+Na]+: 443.1440, found 443.1449.
2-(4-(4-Ethylcyclohexyl)phenyl)-3-(phenylthio)benzofuran (3am): Yield: 75% (61.8 mg) as a
yellow solid; mp = 63.3 ꢀ 64.6 °C; 1H NMR (400 MHz, CDCl3) δ 8.14 (d, J = 8.0 Hz, 2H), 7.53 (d,
J = 8.0 Hz, 1H), 7.46 (d, J = 7.6 Hz, 1H), 7.31 ꢀ 7.25 (m, 3H), 7.23 ꢀ 7.14 (m, 5H), 7.12 ꢀ 7.04 (m,
1H), 2.49 (t, J = 12.0 Hz, 1H), 1.89 (t, J = 11.6 Hz, 4H), 1.45 (dd, J = 23.2, 11.6 Hz, 2H), 1.26 (dt,
J = 13.2, 6.6 Hz, 3H), 1.04 (dd, J = 23.2, 11.2 Hz, 2H), 0.90 (t, J = 7.2 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 158.0, 153.9, 149.6, 136.5, 131.0, 129.1, 127.5, 127.4, 127.1, 126.5, 125.5, 125.1,
123.4, 120.3, 111.3, 103.8, 44.6, 39.1, 34.2, 33.1, 30.0, 11.5 ppm; νmax(KBr)/cmꢀ1 3044, 2932,
1628, 1446, 1418, 1406, 1022, 686; HRMSꢀESI (m/z): calcd for C28H28NaOS, [M+Na]+: 435.1753,
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3-(Phenylthio)-2-(thiophen-2-yl)benzofuran (3an)10a : Yield: 68% (50.5 mg) as a yellow solid;
mp = 123.2 ꢀ 124.5 °C; 1H NMR (400 MHz, CDCl3) δ 7.88 (d, J = 3.6 Hz, 1H), 7.49 (dd, J = 17.2,
8.0 Hz, 2H), 7.39 (d, J = 4.0 Hz, 1H), 7.31 ꢀ 7.28 (m, 1H), 7.24 ꢀ 7.16 (m, 5H), 7.12 ꢀ 7.06 (m, 2H);
13C NMR (100 MHz, CDCl3) δ 154.2, 153.9, 135.8, 131.3, 130.7, 129.1, 128.2, 127.6, 127.5,
126.9, 125.8, 125.3, 123.7, 120.1, 111.3, 103.7 ppm; νmax(KBr)/cmꢀ1 3038, 2934, 1628, 1448, 1410,
1032, 692; MS (EI) m/z 127, 171, 203, 247, 275, 308; HRMSꢀESI (m/z): calcd for C18H12NaOS2,
[M+Na]+: 331.0222, found 331.0220.
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2-Benzyl-3-(phenylthio)benzofuran (3ao): Yield: 72% (45.5 mg) as a yellow oil; 1H NMR (400
MHz, CDCl3) δ 7.42 (t, J = 6.4 Hz, 2H), 7.30 ꢀ 7.22 (m, 5H), 7.20 ꢀ 7.02 (m, 7H), 4.27 (s, 2H); 13
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NMR (100 MHz, CDCl3) δ 161.6, 154.6, 137.0, 136.6, 129.4, 129.0, 128.9, 128.7, 126.8, 126.7,
125.5, 124.6, 123.3, 120.1, 111.4, 105.6, 33.0 ppm; νmax(KBr)/cmꢀ1 3046, 2935, 1630, 1447, 1405,
1020, 688; MS (EI) m/z 152, 178, 207, 239, 283, 316; HRMSꢀESI (m/z): calcd for C21H16NaOS,
[M+Na]+: 339.0814, found 339.0819.
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2-Phenethyl-3-(phenylthio)benzofuran (3ap): Yield: 74% (48.8 mg) as a yellow oil; H NMR
(400 MHz, CDCl3) δ 7.56 (d, J = 8.4 Hz, 1H), 7.45 (d, J = 7.6 Hz, 1H), 7.39 ꢀ 7.27 (m, 4H), 7.22
(dd, J = 17.6, 7.2 Hz, 5H), 7.14 (d, J = 6.4 Hz, 1H), 7.08 (d, J = 7.6 Hz, 2H), 3.33 (t, J = 7.6 Hz,
2H), 3.14 (t, J = 7.6 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 162.50, 154.4, 140.5, 136.6, 129.5,
128.9, 128.5, 128.4, 126.7, 126.3, 125.4, 124.4, 123.2, 119.9, 111.2, 105.5, 34.1, 28.7 ppm;
νmax(KBr)/cmꢀ1 3049, 2933, 1635, 1448, 1405, 1026, 687; MS (EI) m/z 121, 165, 178, 211, 239,
296, 330; HRMSꢀESI (m/z): calcd for C22H18NaOS, [M+Na]+: 353.0971, found 353.0972.
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NMR (400 MHz, CDCl3) δ 7.47 (d, J = 8.0 Hz, 1H), 7.41 (d, J = 7.6 Hz, 1H), 7.26 (dd, J = 15.2,
6.8 Hz, 4H), 7.21 ꢀ 7.05 (m, 8H), 2.98 (t, J = 7.2 Hz, 2H), 2.67 (t, J = 7.6 Hz, 2H), 2.23 ꢀ 1.97 (m,
2H); 13C NMR (100 MHz, CDCl3) δ 163.5, 154.4, 141.6, 136.9, 129.6, 128.9, 128.4, 128.3, 126.5,
125.9, 125.4, 124.3, 123.2, 119.8, 111.1, 104.7, 35.3, 29.6, 26.3 ppm; νmax(KBr)/cmꢀ1 3048, 2936,
1631, 1449, 1403, 1022, 689; MS (EI) m/z 115, 131, 178, 239, 281, 309, 344; HRMSꢀESI (m/z):
calcd for C23H20NaOS, [M+Na]+: 367.1127, found 367.1127.
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2-(4-Chlorobutyl)-3-(phenylthio)benzofuran (3ar): Yield: 70% (48.2 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 7.46 (d, J = 8.0 Hz, 1H), 7.41 (d, J = 7.6 Hz, 1H), 7.27 (t, J = 7.6 Hz,
1H), 7.18 (dd, J = 12.8, 7.2 Hz, 3H), 7.09 (dd, J = 13.0, 6.8 Hz, 3H), 3.50 (t, J = 6.4 Hz, 2H), 2.97
(t, J = 7.2 Hz, 2H), 2.01 ꢀ 1.84 (m, 2H), 1.85 ꢀ 1.69 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 162.9,
154.4, 136.8, 129.5, 129.0, 126.5, 125.5, 124.4, 123.3, 119.9, 111.2, 105.2, 44.4, 31.8, 25.8, 25.3
ppm; νmax(KBr)/cmꢀ1 3046, 2936, 1636, 1452, 1400, 1024, 687; MS (EI) m/z 115, 152, 178, 221,
281, 316; HRMSꢀESI (m/z): calcd for C18H17ClNaOS, [M+Na]+: 339.0581, found 339.0581.
5-Methyl-2-phenyl-3-(phenylthio)benzofuran (3as)10a: Yield: 93% (58.8 mg) as a white solid;
mp = 76.5 ꢀ 77.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.04 (d, J = 13.6 Hz, 2H), 7.54 (d, J = 8.0 Hz,
1H), 7.46 (d, J = 7.6 Hz, 1H), 7.31 (t, J = 6.6 Hz, 2H), 7.23 ꢀ 7.13 (m, 6H), 7.12 ꢀ 7.03 (m, 1H),
2.38 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 157.7, 154.0, 138.3, 136.3, 130.9, 130.3, 129.8, 128.5,
126.8, 125.6, 125.2, 124.7, 123.5, 120.4, 111.3, 104.7, 21.6 ppm; νmax(KBr)/cmꢀ1 3043, 2928, 1633,
1445, 1415, 1026, 680; MS (EI) m/z 105, 119, 178, 225, 284, 301, 316; HRMSꢀESI (m/z): calcd
for C21H16NaOS, [M+Na]+: 339.0814, found 339.0818.
Methyl 2-phenyl-3-(phenylthio)benzofuran-5-carboxylate (3at): Yield: 67% (48.2 mg) as a
yellow solid; mp = 116.5 ꢀ 117.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.26 ꢀ 8.20 (m, 3H), 8.07 (dd,
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J = 8.8, 1.6 Hz, 1H), 7.58 (d, J = 8.4 Hz, 1H), 7.48 ꢀ 7.40 (m, 3H), 7.23 ꢀ 7.17 (m, 4H), 7.15 ꢀ 7.09
(m, 1H), 3.89 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 166.9, 159.0, 156.5, 135.8, 131.1, 129.9,
129.3, 129.2, 128.7, 127.5, 127.1, 126.6, 126.0, 125.8, 122.7, 111.3, 105.3, 52.1 ppm;
νmax(KBr)/cmꢀ1 3026, 2928, 1722, 1445, 1408, 1236, 1094, 690; MS (EI) m/z 105, 164, 224, 283,
329, 360; HRMSꢀESI (m/z): calcd for C22H16NaO3S, [M+Na]+: 383.0712, found 383.0715
6-Fluoro-2-phenyl-3-(phenylthio)benzofuran (3au): Yield: 80% (51.2 mg) as a white solid; mp
= 83.7 ꢀ 84.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.21 (d, J = 7.6 Hz, 2H), 7.52 ꢀ 7.35 (m, 4H), 7.23
ꢀ 7.16 (m, 4H), 7.12 (d, J = 6.4 Hz, 2H), 7.02 (t, J = 9.0 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ
159.7 (d, J = 238.7 Hz), 159.3, 150.1, 132.1, 159.7 (d, J = 10.4 Hz), 129.7, 129.5, 129.2, 128.7,
127.5, 126.7, 125.8, 113.1 (d, J = 26.4 Hz), 112.1 (d, J = 9.4 Hz), 106.1 (d, J = 25.4 Hz), 105.0 (d,
J = 4.0 Hz) ppm; νmax(KBr)/cmꢀ1 3048, 1633, 1450, 1403, 1022, 685; MS (EI) m/z 105, 183, 215,
243, 287, 320; HRMSꢀESI (m/z): calcd for C20H13FNaOS, [M+Na]+: 343.0563, found 343.0564.
6-Chloro-2-phenyl-3-(phenylthio)benzofuran (3av)10a : Yield: 82% (55.1 mg) as a yellow solid;
mp = 106.5 ꢀ 108.2 °C; 1H NMR (400 MHz, CDCl3) δ 8.19 (d, J = 7.2 Hz, 2H), 7.54 (s, 1H), 7.47
ꢀ 7.31 (m, 4H), 7.20 ꢀ 7.13 (m, 5H), 7.12 ꢀ 7.06 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 158.1,
154.0, 135.8, 131.1, 129.7, 129.6, 129.4, 129.2, 128.7, 127.4, 126.8, 125.8, 124.3, 121.0, 112.0,
104.9 ppm; νmax(KBr)/cmꢀ1 3036, 2936, 1638, 1441, 1413, 1035, 688; MS (EI) m/z 105, 163, 224,
259, 301, 336; HRMSꢀESI (m/z): calcd for C20H13ClNaOS, [M+Na]+: 359.0268, found 359.0273.
6-Bromo-2-phenyl-3-(phenylthio)benzofuran (3aw): Yield: 77% (58.5 mg) as a yellow solid;
mp = 118.2 ꢀ 119.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.19 (d, J = 7.2 Hz, 2H), 7.70 (s, 1H), 7.40
(dq, J = 14.0, 6.8 Hz, 3H), 7.34 ꢀ 7.25 (m, 2H), 7.20 ꢀ 7.13 (m, 4H), 7.12 ꢀ 7.05 (m, 1H); 13C NMR
(100 MHz, CDCl3) δ 158.0, 154.2, 135.7, 130.0, 129.7, 129.4, 129.2, 128.7, 127.4, 127.0, 126.8,
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125.8, 121.4, 118.6, 114.9, 105.0 ppm; νmax(KBr)/cmꢀ1 3036, 1632, 1455, 1413, 1024, 689; MS (EI)
m/z 105, 163, 195, 224, 268, 301, 353, 380; HRMSꢀESI (m/z): calcd for C20H13BrNaOS, [M+Na]+:
402.9763, found 402.9759.
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NMR (400 MHz, CDCl3) δ 8.18 (d, J = 6.8 Hz, 2H), 8.04 (s, 1H), 7.92 (dd, J = 8.0, 1.2 Hz, 1H),
7.59 (d, J = 8.2 Hz, 1H), 7.50 ꢀ 7.36 (m, 6H), 7.35 ꢀ 7.30 (m, 1H), 7.25 (t, J = 7.2 Hz, 1H); 13C
NMR (100 MHz, CDCl3) δ 158.3, 154.1, 148.8, 139.4, 131.7, 129.9, 129.8, 128.8, 127.4, 125.8,
123.9, 120.9, 120.4, 119.9, 111.7, 102.7 ppm; νmax(KBr)/cmꢀ1 3034, 1636, 1425, 1406, 1028, 684;
MS (EI) m/z 105, 165, 197, 268, 300, 347; HRMSꢀESI (m/z): calcd for C20H13NNaO3S, [M+Na]+:
370.0508, found 370.0504.
2-Phenyl-3-(p-tolylthio)benzofuran (3ba)10a : Yield: 88% (55.6 mg) as a yellow solid; mp = 70.0
ꢀ 71.3 °C; 1H NMR (400 MHz, CDCl3) δ 8.23 (d, J = 7.6 Hz, 2H), 7.51 (d, J = 8.0 Hz, 1H), 7.47
(d, J = 7.6 Hz, 1H), 7.41 (t, J = 7.2 Hz, 2H), 7.35 (d, J = 6.8 Hz, 1H), 7.28 (t, J = 7.6 Hz, 1H),
7.19 (d, J = 7.6 Hz, 1H), 7.10 (d, J = 7.6 Hz, 2H), 6.97 (d, J = 7.6 Hz, 2H), 2.21 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 157.3, 154.0, 135.6, 132.6, 131.1, 123.0, 129.9, 129.4, 128.7, 127.5, 127.0,
125.3, 123.5, 120.6, 111.4, 105.4, 21.0 ppm; νmax(KBr)/cmꢀ1 3042, 2936, 1637, 1448, 1410, 1028,
681; MS (EI) m/z 119, 165, 207, 239, 283, 301, 316; HRMSꢀESI (m/z): calcd for C21H16NaOS,
[M+Na]+: 339.0814, found 339.0818.
3-((4-Methoxyphenyl)thio)-2-phenylbenzofuran (3bb)10a : Yield: 81% (53.8 mg) as a yellow oil;
1H NMR (400 MHz, CDCl3) δ 7.83 (d, J = 7.6 Hz, 1H), 7.79 (s, 1H), 7.54 (d, J = 8.4 Hz, 1H),
7.49 (d, J = 7.6 Hz, 1H), 7.38 ꢀ 7.27 (m, 2H), 7.22 ꢀ 7.14 (m, 5H), 7.09 (dt, J = 8.0, 4.8 Hz, 1H),
6.93 (dd, J = 8.0, 1.6 Hz, 1H), 3.77 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 159.7, 157.3, 153.9,
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136.2, 130.9, 129.7, 129.1, 126.6, 125.6, 125.4, 123.6, 120.5, 119.9, 115.8, 112.4, 111.4, 105.0,
55.3 ppm; νmax(KBr)/cmꢀ1 3034, 2927, 1626, 1444, 1413, 1012, 692; MS (EI) m/z 113, 152, 225,
271, 299, 332; HRMSꢀESI (m/z): calcd for C21H16NaO2S, [M+Na]+: 355.0763, found 355.0763.
3-((2-Methoxyphenyl)thio)-2-phenylbenzofuran (3bc): Yield: 76% (50.5 mg) as a yellow oil;
1H NMR (400 MHz, CDCl3) δ 8.26 (d, J = 7.6 Hz, 2H), 7.51 (d, J = 8.0 Hz, 1H), 7.49 ꢀ 7.41 (m,
3H), 7.38 (d, J = 7.2 Hz, 1H), 7.29 (t, J = 7.6 Hz, 1H), 7.19 (dd, J = 7.0, 6.4 Hz, 3H), 6.74 (d, J =
8.4 Hz, 2H), 3.69 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 158.4, 156.7, 153.9, 130.9, 123.0, 129.3,
129.3, 128.6, 127.4, 126.5, 125.2, 123.4, 120.5, 114.9, 111.3, 106.5, 55.3 ppm; νmax(KBr)/cmꢀ1
3028, 2920, 1636, 1451, 1411, 1026, 689; MS (EI) m/z 105, 139, 165, 227, 255, 299, 317, 332;
HRMSꢀESI (m/z): calcd for C21H16NaO2S, [M+Na]+: 355.0763, found 355.0770.
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3-((4-Fluorophenyl)thio)-2-phenylbenzofuran (3bd)10a : Yield: 78% (49.9 mg) as a yellow solid;
mp = 55.0 ꢀ 56.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 7.2 Hz, 2H), 7.54 (d, J = 8.0 Hz,
1H), 7.44 (t, J = 7.2 Hz, 3H), 7.39 (d, J = 7.2 Hz, 1H), 7.32 (t, J = 7.6 Hz, 1H), 7.22 ꢀ 7.13 (m, 3H),
6.89 (t, J = 8.4 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 161.4 (d, J = 243.9 Hz), 157.3, 154.0,
131.1 (d, J = 3.2 Hz), 130.7, 129.8, 129.5, 128.8 (d, J = 8.2 Hz), 128.6, 127.4, 125.4, 123.6, 120.3,
116.2 (d, J = 21.0 Hz), 111.4, 105.3 ppm; νmax(KBr)/cmꢀ1 3038, 2934, 1636, 1443, 1414, 1026,
687; MS (EI) m/z 105, 165, 197, 243, 291, 320; HRMSꢀESI (m/z): calcd for C20H13FNaOS,
[M+Na]+: 343.0563, found 343.0562.
3-((3-Fluorophenyl)thio)-2-phenylbenzofuran (3be)10a : Yield: 75% (48.0 mg) as a white solid;
mp = 65.4 ꢀ 67.2 °C; 1H NMR (400 MHz, CDCl3) δ 8.19 (d, J = 7.2 Hz, 2H), 7.56 (d, J = 8.4 Hz,
1H), 7.51 ꢀ 7.29 (m, 5H), 7.24 (d, J = 7.2 Hz, 1H), 7.13 (dd, J = 14.4, 7.2 Hz, 1H), 6.96 (d, J = 7.6
Hz, 1H), 6.86 (d, J = 9.2 Hz, 1H), 6.77 (t, J = 8.4 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 163.2
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(d, J = 246.8 Hz), 157.9, 154.0, 138.9, 138.8, 130.6, 130.4 (d, J = 8.5 Hz), 129.6 (d, J = 3.9 Hz),
128.7, 127.5, 125.5, 123.7, 121.9 (d, J = 2.8 Hz), 120.3, 113.3 (d, J = 24.0 Hz), 112.5 (d, J = 21.3
Hz), 111.5, 103.8 ppm; νmax(KBr)/cmꢀ1 3026, 2934, 1638, 1445, 1408, 1026, 686; MS (EI) m/z
105, 165, 197, 243, 291, 320; HRMSꢀESI (m/z): calcd for C20H13FNaOS, [M+Na]+: 343.0563,
found 343.0563.
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3-((4-Chlorophenyl)thio)-2-phenylbenzofuran (3bf)10a : Yield: 79% (53.1 mg) as a white solid;
mp = 80.5 ꢀ 81.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.19 (d, J = 7.2 Hz, 2H), 7.53 (d, J = 8.0 Hz,
1H), 7.47 ꢀ 7.35 (m, 4H), 7.30 (t, J = 7.6 Hz, 1H), 7.21 (d, J = 7.6 Hz, 1H), 7.10 (q, J = 8.8 Hz,
4H); 13C NMR (100 MHz, CDCl3) δ 157.7, 154.1, 134.8, 131.6, 130.6, 129.7, 129.6, 129.3, 128.7,
127.9, 127.5, 125.5, 123.7, 120.3, 111.5, 104.3 ppm; νmax(KBr)/cmꢀ1 3038, 2930, 1634, 1445, 1411,
1026, 686; MS (EI) m/z 105, 165, 197, 268, 301, 336; HRMSꢀESI (m/z): calcd for C20H13ClNaOS,
[M+Na]+: 359.0268, found 359.0273.
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3-((4-Nitrophenyl)thio)-2-phenylbenzofuran (3bg)9 : Yield: 64% (44.3 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.14 (d, J = 7.6 Hz, 2H), 8.04 (d, J = 8.4 Hz, 2H), 7.61 (d, J = 8.0 Hz,
1H), 7.48 ꢀ 7.36 (m, 5H), 7.25 (t, J = 7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 158.5, 154.1,
146.2, 145.5, 130.0, 129.2, 128.8, 127.4, 125.8, 125.8, 124.3, 123.9, 119.9, 111.7, 102.1 ppm;
νmax(KBr)/cmꢀ1 3046, 2936, 1634, 1444, 1412, 1032, 680; MS (EI) m/z 105, 165, 197, 225, 268,
301, 347; HRMSꢀESI (m/z): calcd for C20H13NNaO3S, [M+Na]+: 370.0508, found 370.0503.
3-((3,4-Dichlorophenyl)thio)-2-phenylbenzofuran (3bh): Yield: 71% (53.1 mg) as a white solid;
mp = 119.7 ꢀ 121.1 °C; 1H NMR (400 MHz, CDCl3) δ 8.16 (d, J = 7.2 Hz, 2H), 7.57 (d, J = 8.0 Hz,
1H), 7.50 ꢀ 7.39 (m, 4H), 7.36 (t, J = 7.6 Hz, 1H), 7.26 (t, J = 7.6 Hz, 1H), 7.07 (s, 1H), 7.01 (s,
2H); 13C NMR (100 MHz, CDCl3) δ 158.3, 154.0, 140.3, 135.6, 130.2, 129.9, 129.4, 128.8, 127.5,
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125.8, 125.7, 124.1, 123.9, 120.0, 111.6, 102.6 ppm; νmax(KBr)/cmꢀ1 3034, 1635, 1456, 1415, 1024,
687; MS (EI) m/z 105, 165, 197, 225, 271, 293, 341, 370; HRMSꢀESI (m/z): calcd for
C20H12Cl2NaOS, [M+Na]+: 392.9878, found 392.9876.
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2-Phenyl-3-(phenylthio)-1H-indole (5aa)15a : Yield: 90% (54.2 mg) as a yellow oil; H NMR
(400 MHz, CDCl3) δ 8.49 (s, 1H), 7.72 (d, J = 7.6 Hz, 2H), 7.62 (d, J = 7.6 Hz, 1H), 7.37 (dt, J =
21.2, 6.8 Hz, 4H), 7.25 (t, J = 7.6 Hz, 1H), 7.13 (dt, J = 15.6, 7.2 Hz, 5H), 7.03 (t, J = 6.8 Hz, 1H);
13C NMR (100 MHz, CDCl3) δ 142.1, 139.3, 135.9, 131.5, 131.2, 128.8, 128.8, 128.7, 128.2,
125.6, 124.7, 123.4, 121.2, 120.0, 111.2, 99.5 ppm; νmax(KBr)/cmꢀ1 3028, 2936, 1626, 1443, 1410,
1022, 685; MS (EI) m/z 121, 165, 197, 223, 268, 301.
5-Methyl-2-phenyl-3-(phenylthio)-1H-indole (5ab)15a : Yield: 87% (54.8 mg) as a yellow solid;
mp = 116.8 ꢀ 118.2 °C; 1H NMR (400 MHz, CDCl3) δ 8.40 (s, 1H), 7.70 (d, J = 7.2 Hz, 2H), 7.45
ꢀ 7.32 (m, 4H), 7.29 (d, J = 8.4 Hz, 1H), 7.14 (t, J = 7.2 Hz, 2H), 7.11 ꢀ 7.00 (m, 4H), 2.39 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 142.2, 139.6, 134.2, 131.6, 130.7, 128.9, 128.8, 128.6, 128.1,
125.5, 125.1, 124.6, 119.5, 110.9, 98.7, 21.5 ppm; νmax(KBr)/cmꢀ1 3034, 2934, 1624, 1446, 1413,
1025, 689; MS (EI) m/z 121, 165, 204, 223, 238, 267, 282, 315; HRMSꢀESI (m/z): calcd for
C21H17NNaS, [M+Na]+: 338.0974, found 338.0969.
6-Methyl-2-phenyl-3-(phenylthio)-1H-indole (5ac): Yield: 89% (56.1 mg) as a yellow solid; mp
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= 129.7 ꢀ 130.7 °C; H NMR (400 MHz, CDCl3) δ 8.39 (s, 1H), 7.69 (d, J = 7.2 Hz, 2H), 7.46 ꢀ
7.32 (m, 4H), 7.28 (d, J = 8.0 Hz, 1H), 7.14 (t, J = 7.6 Hz, 2H), 7.11 ꢀ 6.99 (m, 5H), 2.39 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 142.2, 139.6, 134.2, 131.6, 130.7, 128.8, 128.8, 128.6, 128.1,
125.5, 125.1, 124.6, 119.5, 110.9, 98.6, 21.5 ppm; νmax(KBr)/cmꢀ1 3370, 2938, 1618, 1447, 1406,
1340, 675; MS (EI) m/z 128, 151, 178, 242, 257, 315; HRMSꢀESI (m/z): calcd for C21H17NNaS,
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[M+Na]+: 338.0974, found 338.0980.
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5-Methoxy-2-phenyl-3-(phenylthio)-1H-indole (5ad): Yield: 77% (50.9 mg) as a yellow solid;
mp = 145.2 ꢀ 146.4 °C; 1H NMR (400 MHz, CDCl3) δ 8.49 (s, 1H), 7.68 (d, J = 7.6 Hz, 2H), 7.41
ꢀ 7.30 (m, 3H), 7.26 (d, J = 8.4 Hz, 1H), 7.18 ꢀ 6.99 (m, 6H), 6.89 (d, J = 8.8 Hz, 1H), 3.75 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 155.3, 142.7, 139.3, 132.2, 131.5, 130.8, 128.9, 128.8, 128.6,
128.1, 125.5, 124.7, 113.8, 112.2, 101.2, 98.9, 55.8 ppm; νmax(KBr)/cmꢀ1 3356, 2936, 1616, 1445,
1408, 1333, 676; MS (EI) m/z 107, 152, 183, 199, 277, 331; HRMSꢀESI (m/z): calcd for
C21H17NNaOS, [M+Na]+: 354.0923, found 354.0928.
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5,7-Dimethyl-2-phenyl-3-(phenylthio)-1H-indole (5ae): Yield: 83% (54.6 mg) as a yellow solid;
mp = 156.1 ꢀ 157.7 °C; 1H NMR (400 MHz, CDCl3) δ 8.33 (s, 1H), 7.73 (d, J = 7.6 Hz, 2H), 7.40
(t, J = 7.2 Hz, 2H), 7.35 (d, J = 7.2 Hz, 1H), 7.27 (s, 1H), 7.17 ꢀ 7.08 (m, 4H), 7.03 (t, J = 6.8 Hz,
1H), 6.90 (s, 1H), 2.50 (s, 3H), 2.37 (s, 3H); 13C NMR (100 MHz, CDCl3) δ142.0, 139.6, 133.7,
131.7, 131.2, 130.9, 128.8, 128.7, 128.6, 128.2, 125.8, 125.5, 124.5, 120.0, 117.2, 99.2, 21.5, 16.4
ppm; νmax(KBr)/cmꢀ1 3360, 2932, 1628, 1450, 1332, 682; MS (EI) m/z 115, 150, 237, 281, 296,
313, 329; HRMSꢀESI (m/z): calcd for C22H19NNaS, [M+Na]+: 352.1130, found 352.1137.
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5-Fluoro-2-phenyl-3-(phenylthio)-1H-indole (5af): Yield: 81% (51.6 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.40 (s, 1H), 7.62 (d, J = 7.2 Hz, 2H), 7.29 (dd, J = 16.0, 7.6 Hz, 3H),
7.24 ꢀ 7.14 (m, 2H), 7.06 (t, J = 7.2 Hz, 2H), 6.96 (dd, J = 14.8, 7.6 Hz, 3H), 6.88 (t, J = 8.8 Hz,
1H); 13C NMR (100 MHz, CDCl3) δ 158.8 (d, J = 235.7 Hz), 143.8, 138.8, 132.2 (d, J = 2.5 Hz),
132.1, 129.0, 128.9, 128.8, 128.1, 125.7, 124.9, 112.1 (d, J = 9.4 Hz), 111.8 (d, J = 26.4 Hz),
105.0 (d, J = 24.1 Hz), 99.6 (d, J = 4.5 Hz) ppm; νmax(KBr)/cmꢀ1 3357, 2936, 1625, 1456, 1338,
689; MS (EI) m/z 139, 183, 215, 241, 285, 304, 319; HRMSꢀESI (m/z): calcd for C20H14FNNaS,
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[M+Na]+: 342.0723, found 342.0718.
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6-Chloro-2-phenyl-3-(phenylthio)-1H-indole (5ag): Yield: 84% (56.3 mg) as a yellow solid; mp
= 114.7 ꢀ 115.5 °C; 1H NMR (400 MHz, CDCl3) δ 8.50 (s, 1H), 7.71 (d, J = 7.2 Hz, 2H), 7.50 (d, J
= 8.4 Hz, 1H), 7.46 ꢀ 7.32 (m, 4H), 7.17 ꢀ 7.10 (m, 3H), 7.08 ꢀ 7.01 (m, 3H); 13C NMR (100 MHz,
CDCl3) δ 142.6, 138.8, 136.2, 131.0, 129.8, 129.2, 129.0, 128.9, 128.8, 128.1, 125.7, 124.9, 121.9,
120.9, 111.2, 99.9 ppm; νmax(KBr)/cmꢀ1 3368, 2931, 1623, 1456, 1348, 686; MS (EI) m/z 121, 150,
223, 267, 300, 335; HRMSꢀESI (m/z): calcd for C20H14ClNNaS, [M+Na]+: 358.0428, found
358.0432.
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5,7-Dichloro-2-phenyl-3-(phenylthio)-1H-indole (5ah): Yield: 71% (52.4 mg) as a yellow solid;
mp = 116.9 ꢀ 118.8 °C; 1H NMR (400 MHz, CDCl3) δ 8.69 (s, 1H), 7.75 (d, J = 7.2 Hz, 2H), 7.51
(s, 1H), 7.47 ꢀ 7.36 (m, 3H), 7.25 (s, 1H), 7.17 (t, J = 7.6 Hz, 2H), 7.06 (t, J = 8.0 Hz, 3H); 13C
NMR (100 MHz, CDCl3) δ 144.2, 138.3, 133.2, 131.7, 130.5, 129.4, 129.0, 128.9, 128.2, 127.1,
125.7, 125.1, 122.9, 118.3, 117.0, 100.7 ppm; νmax(KBr)/cmꢀ1 3320, 2948, 1636, 1458, 1366, 687;
MS (EI) m/z 150, 257, 301, 337, 369; HRMSꢀESI (m/z): calcd for C20H13Cl2NNaS, [M+Na]+:
392.0038, found 392.0037.
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5-Bromo-2-phenyl-3-(phenylthio)-1H-indole (5ai): Yield: 80% (60.9 mg) as a yellow oil; H
NMR (400 MHz, CDCl3) δ 8.49 (s, 1H), 7.69 (s, 1H), 7.64 (d, J = 6.8 Hz, 2H), 7.32 (dd, J = 15.6,
7.2 Hz, 3H), 7.25 (d, J = 8.8 Hz, 1H), 7.20 (d, J = 8.4 Hz, 1H), 7.08 (t, J = 7.2 Hz, 2H), 6.98 (d, J
= 7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 143.3, 138.8, 134.5, 133.1, 130.9, 129.1, 128.9,
128.8, 128.1, 126.4, 125.6, 124.9, 122.5, 114.7, 112.7, 99.2 ppm; νmax(KBr)/cmꢀ1 3408, 2954, 1630,
1449, 1346, 689; MS (EI) m/z 121, 150, 190, 223, 267, 300, 347, 381; HRMSꢀESI (m/z): calcd for
C20H14BrNNaS, [M+Na]+: 401.9923, found 401.9927.
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2-Phenyl-3-(phenylthio)-5-(trifluoromethyl)-1H-indole (5aj): Yield: 70% (51.7 mg) as a yellow
solid; mp = 247.4 ꢀ 248.5 °C; 1H NMR (400 MHz, CDCl3) δ 8.72 (s, 1H), 7.94 (s, 1H), 7.72 (d, J
= 7.2 Hz, 2H), 7.47 (s, 2H), 7.43 ꢀ 7.32 (m, 3H), 7.15 (t, J = 7.2 Hz, 2H), 7.11 ꢀ 7.00 (m, 3H); 13C
NMR (100 MHz, CDCl3) δ 143.8, 138.6, 137.2, 130.9, 130.7, 129.2, 129.0, 128.9, 128.2, 125.7,
125.0, 123.6 (q, J = 41.6 Hz), 120.2 (q, J = 3.4 Hz), 111.7 (q, J = 4.0 Hz), 111.6, 100.7 ppm;
νmax(KBr)/cmꢀ1 3396, 2938, 1628, 1454, 1370, 681; MS (EI) m/z 121, 150, 188, 267, 337, 369;
HRMSꢀESI (m/z): calcd for C21H14F3NNaS, [M+Na]+: 392.0691, found 392.0697.
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Methyl 2-phenyl-3-(phenylthio)-1H-indole-5-carboxylate (5ak): Yield: 64% (45.9 mg) as a
yellow solid; mp = 253.5 ꢀ 253.9 °C; 1H NMR (400 MHz, CDCl3) δ 8.39 (s, 1H), 7.99 (d, J = 8.4
Hz, 1H), 7.77 (d, J = 7.2 Hz, 2H), 7.44 (dd, J = 19.6, 12.0 Hz, 4H), 7.17 (t, J = 7.2 Hz, 2H), 7.08
(d, J = 7.2 Hz, 3H), 3.90 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 167.8, 143.5, 138.9, 138.4, 131.0,
130.9, 129.1, 128.9, 128.8, 128.1, 125.6, 124.9, 124.8, 123.5, 122.7, 110.9, 51.9 ppm;
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max(KBr)/cmꢀ1 3361, 2942, 1626, 1443, 1326, 685; MS (EI) m/z 121, 163, 223, 267, 299, 327,
359; HRMSꢀESI (m/z): calcd for C22H17NNaO2S, [M+Na]+: 382.0872, found 382.0872.
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3-(Phenylthio)-2-(p-tolyl)-1H-indole (5ba)15b : Yield: 89% (56.1 mg) as a yellow oil; H NMR
(400 MHz, CDCl3) δ 8.42 (s, 1H), 7.61 (d, J = 7.2 Hz, 3H), 7.38 (d, J = 8.0 Hz, 1H), 7.21 (t, J =
9.2 Hz, 3H), 7.16 ꢀ 7.06 (m, 5H), 7.01 (t, J = 6.4 Hz, 1H), 2.34 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 142.3, 139.4, 138.8, 135.8, 131.3, 129.5, 128.8, 128.6, 128.0, 125.6, 124.6, 123.2, 121.1,
119.9, 111.1, 99.0, 21.4 ppm; νmax(KBr)/cmꢀ1 3038, 2936, 1623, 1440, 1412, 1034, 686; MS (EI)
m/z 121, 150, 204, 238, 267, 283, 315; HRMSꢀESI (m/z): calcd for C21H17NNaS, [M+Na]+:
338.0974, found 338.0973.
2-(4-Methoxyphenyl)-3-(phenylthio)-1H-indole (5bb)15b : Yield: 83% (54.9 mg) as a yellow oil;
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