Fe(III)-Catalyzed direct C3 chalcogenylation of indole: The effect of iodide ions

Article abstract of DOI:10.1016/j.tet.2019.01.037

A mild and efficient iron (III)-catalyzed C3 chalcogenylation of indoles has been developed and the role of the iodide ions in this transformation was investigated. EPR experiments revealed the reduction of Fe(III) to Fe(II) under the reaction conditions, supporting the formation of molecular iodine in the system, which in effect catalyze the reaction. The scope of the chalcogenylation was broad and the synthesis of more functionalized 3-selenylindoles was explored.

Full text of DOI:10.1016/j.tet.2019.01.037

Accepted Manuscript
Fe(III)-Catalyzed direct C3 chalcogenylation of indole: The effect of iodide ions
Eduardo Q. Luz, Diego Seckler, Janylson Souza Araújo, Leonardo Angst, David B.
Lima, Elise Ane Maluf Rios, Ronny R. Ribeiro, Daniel S. Rampon
PII:
S0040-4020(19)30064-X
https://doi.org/10.1016/j.tet.2019.01.037
TET 30089
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 5 November 2018
Revised Date: 9 January 2019
Accepted Date: 17 January 2019
Please cite this article as: Luz EQ, Seckler D, Araújo JS, Angst L, Lima DB, Maluf Rios EA, Ribeiro
RR, Rampon DS, Fe(III)-Catalyzed direct C3 chalcogenylation of indole: The effect of iodide ions,
Tetrahedron (2019), doi: https://doi.org/10.1016/j.tet.2019.01.037.
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Fe(III)-Catalyzed Direct C3
Chalcogenylation of Indole: The Effect of
Iodide Ions
Eduardo Q. Luz,a Diego Seckler, a Janylson Souza Araújo,a Leonardo Angst, a David B. Lima, a Elise Ane Maluf
Rios, a Ronny R. Ribeirob and Daniel S. Rampon*a

1
ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
Fe(III)-Catalyzed Direct C3 Chalcogenylation of Indole: The Effect of Iodide Ions
Eduardo Q. Luz,a Diego Seckler,a Janylson Souza Araújo,a Leonardo Angst,a David B. Lima,a Elise Ane
Maluf Rios,a Ronny R. Ribeiro,b and Daniel S. Rampona,*
a Laboratory of Polymers and Molecular Catalysis (LAPOCA), Department of Chemistry, Federal University of Paraná–UFPR, P. O. Box 19032, Curitiba, PR,
81531-990, Brazil.
b Department of Chemistry, Federal University of Paraná–UFPR, P. O. Box 19032, Curitiba, PR, 81531-990, Brazil.
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A mild and efficient iron (III)-catalyzed C3 chalcogenylation of indoles has been developed and
the role of the iodide ions in this transformation was investigated. EPR experiments revealed the
reduction of Fe(III) to Fe(II) under the reaction conditions, supporting the formation of
molecular iodine in the system, which in effect catalyze the reaction. The scope of the
chalcogenylation was broad and the synthesis of more functionalized 3-selenylindoles was
explored.
Available online
Keywords:
Direct Chalcogenylation
Indoles
2019 Elsevier Ltd. All rights reserved
.
3-selenylindoles
Iron (III)
Iodides
1. Introduction
of a wide variety of 3-chalcogenylindoles regardless of the
expensive and toxic nature of most metal catalysts employed.
These approaches also allowed the positional control of C-H
chalcogenylation, which is a challenging issue under metal free
methodologies.17
The functionalization of 1H-indole core has received
considerable attention1 since this heterocycle is an important
structural unit in many bioactive compounds and organic
materials with technological interest.2,3 Among them, 3-
chalcogenylindoles has been an emergent class of synthetic
structures due their potential therapeutic value in the treatment of
different diseases such HIV,4 cancer,5 cardiovascular,6 allergies,7
and bacterial diseases.8 Further, it also has been used as potent
inhibitor of tubulin polymerization,8 as cyclooxygenase-2 (COX-
2) inhibitors,9 and exhibited antinociceptive properties.10
In contrast, iron is one of the most abundant metals on earth,
and consequently one of the most inexpensive and
environmentally friendly.18 Despite the advantages of iron
catalysis,19 its use for synthesis of 3-chalcogenylindoles was little
explored.20 Fang and co-workers reported the selective C3
sulfenylation of indoles with diorganoyl disulfides using iron
(III) fluoride combined with a catalytic amount of molecular
iodine (I2) in acetonitrile.20a The sulfenylation of indole was also
reported with thiols and iron (III) chloride with excellent
selectivity and good yields.20b Taking into account the synthesis
of 3-selenylindoles catalyzed by Fe(III)/I2, there are no reports
about a systematic mechanistic studies in which these attractive
methods were carefully investigated. Particularly, the reaction
between iron (III) and iodide ions in solution is a well suited way
to produce I2 that could catalyze a number of reactions,21
including the chalcogenylation of indoles with diorganyl
dichalcogenides.21g Nonetheless, it is surprising that this cheap
and simple system was just evaluated in catalytic reactions for air
oxidative coupling of thiols to disulfides without detailed
mechanistic studies.22
On the other hand, organoselenium compounds are well-
known for their biological activities11 and synthetic
applicability,12 making them attractive targets. Furthermore, they
are incredibly useful from functional organic materials
perspective, employed for architecture of electroconductive
polymers, organic semiconductors, and liquid crystals.13 Thus,
undoubtedly there is a great demand for the development of
straightforward construction of C-S and C-Se bonds.
The methodologies reported for the preparation of 3-
chalcogenylindoles
commonly
involve
the
direct
chalcogenylation of indole nucleus with various electrophilic
organochalcogen reagents.14 However, these methods are limited
by either the instability or inaccessibility of the reagents, and/or
incompatibility of the substrates. Besides, the metal free
conditions employing safe diorganoyl dichalcogenides also has
attracted interest,15 although the use of stoichiometric amount of
activators is often a drawback. The transition metal catalyzed
direct chalcogenylation of indoles also have been developed,16
and these reactions have proven to be efficient for the synthesis
In this perspective, herein we detail a new protocol for
synthesis
of
3-chalcogenylindoles
from
diorganoyl
dichalcogenides and indoles derivatives using the Fe(III)/KI
system. The mechanism of this mild and quick reaction was

2
investigated, thus providing a comprehensive data about these
poorly studied catalysts combination in organic reactions.
KI in this methodology since the improved product yields were
ACCEPTED MANUSCRIPT
not detected with other halide ions (entries 4-7). In addition, in
absence of a Fe(III) catalyst the reaction was ineffective (entry
8).
2. Results and Discussion
In order to get the optimized reaction conditions, the
selenylation of indole 1a with diphenyl diselenide 2a was
selected as the model reaction using iron (III) chloride (FeCl3) as
catalyst and a series of additives in DMSO (Table 1). Initially,
the reaction was carried out with 10 mol% of catalyst and 0.5
This prompted us to evaluate the temperature and time of the
reaction in the presence of iodide ion as additive. Fortunately, the
decreasing of reaction temperature to 60 oC produced no
appreciable variation in the product yield (entry 9), but a
considerable decreased was observed under lower temperatures
(entries 9-11). Based on these data, the reaction was followed by
thin layer chromatography (TLC), which indicated that the
starting materials were consumed after only 3 h, with the
selenylated product being obtained in 95% yield (entry 12). It is
worth noting that this could be considered one of the mildest
protocols to access 3-selenylindoles through transition metal
catalysis with diorganoyl diselenides.16,17,20a,20c Additionally, the
yield of 3a remained high when only 10 mol% of KI was
employed (entry 13), whereas a further decrease in the amount of
this additive gave 65% yield (entry 14).
o
equivalent of 2a at 110 C under an air atmosphere, which gave
the desired product 3a in 75% yield after 24 h (Table 1, entry 1).
This reactivity pattern suggests the formation of electrophilic
organoselenium species in this reaction conditions since the C-3
selectivity of 1H-indole under electrophilic aromatic substitutions
is well known.
Table 1. Optimization of the reaction conditions.
All of these results described above indicated that there is a
proper stoichiometry between Fe(III) and iodide ions in this
catalytic system. Furthermore, when the reaction was performed
with 5 mol% of FeCl3 and 5 mol% of KI reasonably good yield
of 3a was obtained only after 24 h (entry 15). Several other
Fe(III) sources were tested (entries 16-19), however only
moderate yields of the product could be achieved and no reaction
was detected with Fe2O3. The detrimental effect of water in this
system was properly observed with FeCl3.6 H2O (entry 19). In
this sense, taking into account the hygroscopic nature of FeCl3, it
was expected a reduction of yields if the H2O from catalyst
contamination was present, and this were not observed under
optimized conditions. Also, since iron is often contaminated with
trace amounts of copper,24 the reaction was carried out with
Cu2O, and only 32% yield of 3a was found. These findings show
the essential role of Fe(III) catalyst in this methodology. Next,
the influence of the cation was investigated in this
transformation. In this regard, the yield of product 3a remained
high with either NaI or CsI, which supports no cation effects in
this reaction (entries 21 and 22). Finally, without KI the reaction
afforded only 12% of 3-(phenylselenyl)-1H-indole 3a (entry 23).
Additive
(mol%)
Time
[h]
Catalyst
(mol%)
Temp.
[ºC]
Yield
[%]b
a
#
1
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
-
-
24
24
24
24
24
24
24
24
24
24
24
3
110
80
75
51
75
91
75
64
49
14
94
82
33
95
97
65
82
-
2
-
3
-
130
110
110
110
110
110
60
4
KI (30)
KBr (30)
KCl (30)
KF (30)
KI (30)
KI (30)
KI (30)
KI (30)
KI (30)
KI (10)
KI (5)
KI (5)
KI (10)
KI (10)
KI (10)
KI (10)
KI (10)
NaI (10)
CsI (10)
-
5
6
7
8
9
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (5)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
40
25
60
3
60
With these conditions in hands, some representative solvents
were screened to verify that DMSO was the most efficient one
for this reaction system (Table 2). Interestingly, acceptable yield
of the product 3a was obtained only in DMF (Table 2, entry 1),
and other solvents such as 1,4-dioxane, acetonitrile or ethanol
gave unsatisfactory results (entries 2-4). Unfortunately, when the
reactions were carried out with toluene or 1,2-dichloroethane the
expected product was not obtained.
3
60
24
3
60
Fe2O3 (10)
FeBr3 (10)
Fe(NO3)3·9 H2O
FeCl3·6 H2O
Cu2O (10)
FeCl3 (10)
FeCl3 (10)
FeCl3 (10)
60
3
60
62
69
52
32
85
95
12
3
60
3
60
3
60
Table 2.The effect of reaction solvent.
3
60
3
60
3
60
aReaction conditions: 1 (1.0 mmol), 2 (0.5 mmol), FeX3 (mol %), additive
(mol %) and dry DMSO (2 mL) under air atmosphere at 60 ºC.
bIsolated yields.
Entrya
Solvent
Yield[%]b
1
2
3
4
5
6
DMF
1,4-Dioxane
CH3CN
EtOH
56
32
21
36
-
The variation of the reaction temperature showed that heating
at 130 oC gave no better result, and lowering the temperature led
to a decrease in the product yield (entries 2 and 3). Considering
that the nucleophilic cleavage of Y-Y bond (S or Se) by attack of
nucleophilic species could be mediated by Lewis acids to
produce electrophilic organochalcogen species23 it was proposed
that the presence of iodide ions under similar conditions could
improve the yield of 3a. In this sense, when 30 mol% of KI was
added to reaction under similar conditions, the yield of 3a was
enhanced to 91% (entry 4). Although this was a distinct effect of
DCE
Toluene
-
aReaction conditions: 1 (1.0 mmol), 2 (0.5 mmol), FeCl3 (10 mol%), KI (10
mol%) and dry solvent (2 mL) under air atmosphere at 60 ºC.
bIsolated yields.

3
To explore the scope and limitation of this method, the
reaction between a variety of indoles (1a-e) and diorganoyl
diselenides (2a-i) were investigated under the best conditions
(Table 3). The progresses of these reactions were also monitored
by TLC. In each case, the reaction regioselectively provided the
3-selenylindoles (3a-3l) in good to excellent yield (61−98%).
When the reactions were performed using 1-methylindole or 1-
benzylindole the desired products 3j and 3k were obtained in
85% and 74% yields, respectively. Furthermore, 2-methylindole
can also react with diphenyl diselenide 2a to produce the
compound 3l in 83% yield. However, indoles with an electron-
withdrawing group at the 1-position (1f) failed to give the
expected product. Surprisingly, and a great particularity of this
system, the protocol allowed a direct access to 2-selenylindoles
(3m) in good yield after 6h when the 3-methyl substituted
heterocycle was used. The C-3 selenylation follow by a C-2
migration offers a possible explanation in this regard.25
The scope of the reaction regarding the preparation of 2- and
ACCEPTED MANUSCRIPT
3-sulfenylindoles was explored next (Table 4). Generally, the
sulfenylation of indoles showed similar electronic effects to those
observed during the selenylation, albeit longer reaction times
were required to reach good to excellent yields of the desired
products (5a-5h). Again, when C-3 position of indole ring was
attached by a methyl group, the C-2 sulfenylation was the
reaction product (5g) probably via a process similar to Plancher
rearrangement.25
Table 4. Synthesis of 2- and 3-thiophenylindoles.a
SR2
FeCl3 (10 mol%)
R2
KI (10 mol%)
S
R2
+
S
DMSO
60oC, Time (h)
N
R1
N
R1
1a-f
5a-j
4a-f
S
The reaction also worked efficiently for structurally diverse
diorganoyl diselenides 2. In general, the product yield from
diaryl diselenides containing electron-withdrawing groups (3b
and 3c) were higher than those with electron-donating groups
(3d, 3e, 3f and 3g), and longer reaction times were required with
these latter substrates to reach good to excellent yields. Notably,
the reaction was effective for dialkyl diselenides, and the
compound 3i was prepared in high yield.
CF3
N
H
5a, 8h, 96%
5b, 5h, 86%
5c, 6h, 84%
Table 3. Synthesis of 2- and 3-selenylindoles.a
5d, 8h, 75%
5e, 8h, 82%
5f, 8h, 72%
5g, 3h, 87%
5h, 6h, 74%
5i, 72h, 0%
aReaction conditions: 1 (1.0 mmol), 4 (0.5 mmol), FeCl3 (10 mol%), KI (10
3a, 3h, 97%
3d, 12h, 76%
3g, 18h, 92%
3b, 3h, 92%
3e, 5h, 78%
3h, 3h, 61%
3c, 3h, 98%
3f, 7h, 95%
3i, 5h, 93%
mol%) and dry DMSO (2 mL) under air atmosphere at 60 ºC, isolated yields.
Considering the high reactivity of indole ring, the synthesized
3-selenylindoles offers several possibilities to prepare more
functionalized compounds, and by the first time this was
evaluated (Scheme 1). This privileged structure have
considerable relevance in transition metal catalyzed reactions,
since catalyst poisoning by organochalcogen species was one of
the serious limiting factors in this area.27 For instance, the
compound 3a underwent a clean Ullmann N-arylation28 on the
indole moiety with 1-iodo-4-methylbenzene, affording 6a in
moderate yield. The straightforward N-alkylation of 3-
selenylindoles constitutes an interesting alternative route to
preparing N-benzyl-3-selenylindoles. Thus, the reaction of 3a
with benzyl chloride, TBAB and K2CO3 gave 3k in 74% isolated
yield.14u The presence of Csp2-Se bond on the organic substrates
also allow potential for further elaboration, particularly in the
formation of new C-C bond. For this purpose, under Zeni and co-
workers conditions,29 the Suzuki reaction between 3i and
phenylboronic acid produced the selectively the C-3 arylation
product 6b.
3j, 3h, 85%
3k, 3h, 74%
3l, 3h, 83%
To clarify the reaction mechanism, some control experiments
were carried out (Scheme 2). Firstly, the addition of the radical
scavenger TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy, 1.0
equiv.) under optimized reaction conditions did not hamper this
transformation and 3a was obtained in 84% isolated yield
(Scheme 2a). This data suggest that a radical pathway is unlikely.
3m, 3h, 76%
3n, 72h, 0%
aReaction conditions: 1 (1.0 mmol), 2 (0.5 mmol), FeCl3 (10 mol%), KI (10
Secondly, considering the plausible formation of molecular
iodine in reaction medium through oxidation of iodide anions
with Fe(III),21c a theoretically maximum amount of I2 (5 mol%)
mol%) and dry DMSO (2 mL) under air atmosphere at 60 ºC, isolated yields.

4
produced under this conditions was used as the only catalyst,
which afforded 3a in 29% yield (Scheme 2b). Notably, when 10
mol% of FeCl3 was employed along with 5 mol% of I2, the
product 3a was obtained in 87% yield (Scheme 2c).
To gain more insight about this selenylation processes, a
ACCEPTED MANUSCRIPT
series of mechanistic studies by Electron Paramagnetic
Resonance (EPR) spectroscopy were performed. The presence of
radical species in the medium and the role of iron in this reaction
could be elucidated since EPR spectroscopy is sensitive to
unpaired electrons, from organic radicals to some transition
metals species.30 Any stable organic radical present in the
samples is expected to result in a narrow EPR spectral line with a
gyromagnetic factor (g) around 2.0; on the other hand, Fe(III)
species manifests spectroscopically as a broader line, around g =
4.3.31 For a given EPR species, the spectral intensity is
proportional to its concentration in the sample.
The progress of the optimized reaction was measured by
taking aliquots at several times, and the spectra were recorded at
77 K (Figure 1, Supporting Information). None of the analyzed
samples presented any signal of organic radicals. Nevertheless,
signals of Fe(III) were present in all samples in DMSO, and their
intensity normalized to concentration suggests that after addition
of 10 mol% of KI the Fe(III) concentration drops 25%, which
indicates the well known equilibrium between Fe(III)/Fe(II) in
the system and the formation of I2. Additionally, after addition of
diphenyl diselenide (2a) and 1H-indole (1a) the Fe(III)
concentration reduced to 47% from the initial value (after 1 h)
due the consumption of I2 for the selenylation reaction.
Considering the aerobic conditions of the system, the Fe(III)
concentration rose during the last 2 h of reaction due to the
expected formation of Fe(III) oxides. On the other hand, when
the reaction was developed with 10 mol% of FeCl2, FeBr2 or FeI2
under optimized conditions, the product 3a was not observed,
which support the essential role of Fe(III) and I2 in this system
and ruled out specific effects of Fe(II).
Scheme 1. Applications of 3-selenylindoles in transition metal
catalyzed reactions and N-alkylations.
These experiments indicated that ArSeI species could be
involved in the mechanism15e,21g and the crucial role of Fe(III) in
this reaction. The essential role of dimethylsulfoxide was also
evaluated (Scheme 2d). Under the optimized reaction conditions
and with polar aprotic solvents (MeCN or DMF), the yield of 3a
remained high when only 1.0 equivalent of DMSO was used,
which corroborates with formation of HI in the system and the
recognized role of DMSO for regenerate iodine.21g Since this
reaction was studied under air conditions, the role of O2 as
terminal oxidant was also evaluated (Scheme 2e). The yields of
3a remained high when the reaction was developed under inert
argon atmosphere and with only 1.0 equivalent of DMSO, which
showed the key role of solvent in this method.
Based on the above results, a plausible mechanism would be
herein presented (Scheme 3). First, the FeCl3 and KI reaches an
equilibrium with the formation of I2 and Fe(II) in the reaction
medium,21 and this is consistent with the EPR experiments.
Subsequently, an electrophilic intermediate of the form RYI (Y =
S, Se) is generated, and the reaction at C-3 position of the indole
derivative catalyzed by Fe(III) that is still present in the system
afford the desired 3-chalcogenylindole, with concomitant
formation of HI.21g The role of iron in this step accounts the mild
reaction conditions observed. Finally, the I2 could be regenerated
through oxidation of hydrogen iodide with DMSO.32,21g,33 Despite
the suggested involvement of RYI (Y = S, Se) species in this
mechanism, their formation are faster than 77Se NMR timescale,34
which avoided the direct observation.
FeCl3 (10 mol%)
KI (10 mol%)
SePh
TEMPO (1.0 equiv.)
Ph
Ph
Ph
Se
(a)
(b)
(c)
(d)
+
+
+
Ph
Ph
Ph
Ph
Se
Se
Se
DMSO
60 oC, 3 h
N
H
N
H
1a
1a
1a
2a
3a
3a
3a
, 84%
SePh
I2 (5 mol%)
Se
DMSO
60 oC, 3 h
N
H
N
H
2a
, 29%
SePh
FeCl3 (10 mol%)
I2 (5 mol%)
Se
DMSO
60 oC, 3 h
N
H
N
H
2a
, 87%
SePh
FeCl3 (10 mol%)
KI (10 mol%)
Ph
Ph
Se
+
Se
DMSO (1.0 equiv.)
MeCN or DMF (2.0 mL)
60 oC, 3 h
N
N
H
H
3a
, 87% (MeCN)
, 79% (DMF)
1a
2a
3a
SePh
FeCl3 (10 mol%)
KI (10 mol%)
Se
(e)
+
Ph
Se
DMSO (1.0 equiv.)
MeCN or DMF (2.0 mL)
60 oC, 3 h
N
H
N
H
3a
3a
, 93% (MeCN)
, 89% (DMF)
1a
2a
Argon Atmosphere
Scheme 2. Preliminary Mechanism Investigation
Scheme 3. Proposed reaction mechanism.

5
3. Conclusion
MHz, CDCl ) δ (ppm) = 464.5, 214.6. MS (Rel. Int.) m/z: 307
(16.3), 227 (100), 192 (8.9), 116 (15.5), 77 (10.0).
ACCEPTED MANUSCRIPT
3
In conclusion, we have disclosed a mild and efficient direct
chalcogenylation of indoles catalyzed by iron (III) chloride and
potassium iodide. The mechanism of this reaction was detailed
by EPR experiments that supports the reduction of Fe(III) to
Fe(II) and the formation of I2 in this system which effectively
catalyzed the reaction. The scope of the chalcogenylation was
broad and the synthesis of more functionalized 3-selenylindoles
and 3-sulfenylindoles were explored.
4.2.3. 3-((3-(Trifluoromethyl)phenyl)selenyl)-1H-indole (3c):21g
Yield: 0.334 g (98%); yelow solid; mp 75-77 ºC. 1H NMR
(CDCl3, 400 MHz) δ (ppm) = 8.46 (br s, 1H); 7.60 (d, J = 8.0 Hz,
1H); 7.54 (s, 1H); 7.49 (d, J = 2.6 Hz, 1H); 7.44 (d, J = 8.0 Hz,
1H); 7.34-7.24 (m, 3H); 7.20-7.16 (m, 2H). 13C NMR (CDCl3,
100 MHz) δ (ppm) = 136.47, 135.25, 131.82, 131.44, 131.2 (q, J
= 318.0 Hz), 129.7, 129.2, 125.2 (q, J = 3.8 Hz), 124.3 (q, J =
268.8 Hz), 123.2, 122.4, (q, J = 4.3 Hz) 121.1, 120.2, 111.5,
97.4. 77Se NMR (76 MHz, CDCl3) δ (ppm) = 464.5, 224.8. MS
(Rel. Int.) m/z: 340 (7.6), 261 (100), 116 (15.9), 77 (10.0).
4.2.4. 3-((4-Methoxyphenyl)seleno)-1H-indole (3d):26a Yield:
0.230 g (76%); white solid; mp 112-115 ºC. 1H NMR (CDCl3,
400 MHz) δ (ppm) = 8.32 (br s, 1H); 7.65 (d, J = 8.8 Hz, 1H);
7.41 (d, J = 2.5 Hz, 1H); 7.38 (d, J = 8.1 Hz, 1H); 7.29-7.13 (m,
4H); 7.38 (d, J = 8.8 Hz, 2H); 3.70 (s, 3H). 13C NMR (CDCl3,
100 MHz) δ (ppm) = 158.4, 136.3, 131.3, 130.5, 129.9, 123.4,
122.8, 120.7, 120.3, 114.8, 111.3, 99.6, 55.2. 77Se NMR (76
MHz, CDCl3) δ (ppm) = 464.5, 202.2. MS (Rel. Int.) m/z: 303
(18.7), 223 (100), 117 (9.8), 77 (14.0).
4. Experimental Section
4.1 General remarks
The reactions were monitored by TLC carried out on Merk
silica gel (60 F254) by using UV light as visualization agent and
the mixture between 5% of vanillin in 10% of H2SO4 under
heating conditions as developing agents. Merck silica gel
(particle size 0.040-0.063 mm) was used to flash
chromatography. Hydrogen nuclear magnetic resonance spectra
(NMR 1H) were obtained at 400 MHz in a Bruker Nuclear
Ascend 400 spectrometer and at 200 MHz in Bruker DPX 200
spectrometer. The spectra were recorded in CDCl3 solutions. The
chemical shifts are reported in ppm, referenced to
tetramethylsilane (TMS) as the internal reference. Coupling
constants (J) are reported in Hertz. Carbon-13 nuclear magnetic
resonance spectra (13C NMR) were obtained at 100 and 50 MHz
spectrometers. Selenium-77 nuclear magnetic resonance spectra
(77Se NMR) were obtained at 76 MHz spectrometers. The
chemical shifts are reported in ppm, referenced to the solvent
peak of CDCl3. High-resolution mass spectra (HRMS) were
recorded in positive ion mode (ESI) using a Q-TOF spectrometer.
Low-resolution mass spectra were obtained with a GCMS-
QP2010 Plus Shimadzu mass spectrometer. X-band Electron
Paramagnetic Resonance (EPR) spectra were recorded on a
Bruker EMX micro spectrometer equipped with a high quality
factor TE102 resonant cavity from frozen DMSO solutions at 77
K. The samples were placed in standard 4 mm o.d. EPR quartz
tubes and the low temperature spectra were obtained using an
insertion quartz finger Dewar. Quantitative analysis were based
on a MgO:Cr intensity standard sample.
4.2.4. 3-(4-tolylselanyl)-1H-indole (3e):15b Yield: 0.223 g (78%);
white solid; mp 104-107 ºC. 1H NMR (CDCl3, 400 MHz) δ
(ppm) = 8.19 (br s, 1H); 7.55 (d, J = 7.8 Hz, 1H); 7.31-7.28 (m,
2H); 7.17-7.13 (m, 1H); 7.10-7.05 (m, 3H); 6.85 (d, J = 7.8 Hz,
1H); 2.14 (s, 3H). 13C NMR (CDCl3, 100 MHz) δ (ppm) = 136.4,
135.5, 131.0, 129.9, 129.7, 129.6, 129.1, 122.8, 120.7, 120.3,
111.3, 98.7, 20.8. 77Se NMR (76 MHz, CDCl3) δ (ppm) = 464.5,
205.8. MS (Rel. Int.) m/z: 287 (19.8), 207 (100), 169 (2.8), 91
(7.3), 77 (6.1).
4.2.5. 3-(mesitylselanyl)-1H-indole (3f): Yield: 0.300 g (95%);
white solid; mp 135-137 ºC. 1H NMR (CDCl3, 400 MHz) δ
(ppm) = 8.09 (br s, 1H); 7.53 (d, J = 8.1 Hz, 1H); 7.29 (d, J = 8.1
Hz, 1H); 7.16 (td, J = 8.1 and 1.3 Hz, 1H); 7.11-7.07 (m, 2H);
6.86 (s, 2H); 2.55 (s, 6H); 2.21 (s, 3H). 13C NMR (CDCl3, 100
MHz) δ (ppm) = 142.5, 137.8, 136.2, 129.6, 128.7, 127.9, 122.4,
120.2, 111.1, 101.1, 24.4 , 20.8. 77Se NMR (76 MHz, CDCl3) δ
(ppm) = 464.5, 125.2. MS (Rel. Int.) m/z: 315 (29.3), 198 (52.9),
119 (13.2), 1/17 (100), 77 (40). HRMS: Calculated mass for
C17H17NSe [M+H]+: 316.0604, found: 316.0605.
4.2.6. 3-((4-(dodecyloxy)phenyl)selanyl)-1H-indole (3g): Yield:
0.209 g (92%); white solid; mp 57-58 ºC H NMR (CDCl3, 400
4.2 General procedure for preparation FeCl3/KI mediated
chalcogenylation of indoles derivatives: A mixture of indole
1a-f (1.0 mmol), dichalcogenide 2a-i or 4a-f (0.5 mmol), FeCl3
(10 mol%) and KI (10 mol%) in dry DMSO (2 mL) was stirred at
60 °C for 3 h until complete consumption of the starting material,
as monitored by TLC. The initial yellow or brownish solution
changes to brown throughout the reaction time. After the reaction
was finished, the brown mixture was poured into EtOAc (15 mL)
and washed with brine (3 × 10 mL), followed by extraction of the
aqueous layer with EtOAc (5 × 3 mL). The combined organic
layer was dried over anhydrous Mg2SO4 and concentrated under
reduced pressure. The crude product was purified by flash
column chromatography (hexane–EtOAc) to afford the 3-
chalcogenyl indole product.
1
MHz) δ (ppm) = 8.27 (br s, 1H), 7.63 (dd, J = 7.9, 1H); 7.37 (d, J
= 2.5 Hz, 1H); 7.34 (d, J= 7.9 Hz, 1H); 7.23-7.18 (m, 3H); 7.13
(td, J = 7.4 and 1.1 Hz, 1H); 6.67 (d, J = 8.7 Hz, 2H); 3.82 (t, J =
6.6 Hz, 2H); 1.68 (p, J = 6.6 Hz, 2H); 1.32-1.12 (m, 18H); 0.86
(t, J = 6.6 Hz, 3H). 13C NMR (CDCl3, 100 MHz) δ(ppm) =
157.9, 136.4, 131.3, 130.5, 129.9, 123.1, 122.8, 120.7, 120.4,
115.4, 111.2, 99.7, 68.1, 31.9, 29.6, 29.6, 29.5, 29.5, 29.3 29.3,
29.2, 26.0, 22.7, 14.1. 77Se NMR (76 MHz, CDCl3) δ (ppm) =
464.5, 202.2. HRMS: Calculated mass for C26H35NOSe [M+H]+:
458.1957, found: 458.1953.
4.2.7. 3-(naphthalen-1-ylselanyl)-1H-indole (3h): Yield: 0.197 g
1
(61%); yellow oil. H NMR (CDCl3, 200 MHz) δ (ppm) = 8.37
(s, 1H); 8.29 (d, J = 8.3 Hz, 1H); 7.72 (dd, J = 7.8 and 1.7 Hz,
1H); 7.64-7.32 (m, 1H); 7.30-6.90 (m, 1H). 77Se NMR (76 MHz,
CDCl3) δ (ppm) = 464.5, 175.2. 13C NMR (CDCl3, 100 MHz) δ
(ppm) = 136.4, 133.7, 132.5, 131.6, 129.8, 128.4, 126.6, 126.1,
126.0, 125.96, 125.9, 125.5, 122.7, 120.6, 120.1, 111.5, 96.6.
HRMS: Calculated mass for C18H13NSe [M+Na]+: 346.0111,
found: 346.0112.
4.2.1. 3-(Phenylselenyl)-1H-indole (3a):21g Yield: 0.265 g (97%);
white solid; mp 134-137 ºC. 1H NMR (CDCl3, 400 MHz) δ
(ppm) = 8.29 (br s, 1H); 7.63 (d, J = 8.0 Hz, 1H); 7.42-7.36 (m,
2H); 7.25-7.20 (m, 3H); 7.17-7.05 (m, 4H). 13C NMR (CDCl3,
100 MHz) δ (ppm) = 136.4, 133.8, 131.2, 130.0, 128.9, 128.7,
125.6, 122.9, 120.8, 120.3, 111.3, 98.2. 77Se NMR (76 MHz,
CDCl3) δ (ppm) = 464.5, 212.0. MS (Rel. Int.) m/z: 273 (20.4),
193 (100), 116 (6.5), 77 (8.3).
4.2.8. 3-(butylselanyl)-1H-indole (3i):16j Yield: 0.236 g (93%);
1
collorless oil. H NMR (CDCl3, 400 MHz) δ (ppm) = 8.14 (br s,
4.2.2. 3-(4-Chlorophenylselenyl)-1H-indole (3b):21g Yield: 0.282
1H); 7.76-7.72 (m, 1H); 7.38-7.26 (m, 1H); 7.28-7.11 (m, 3H);
2.67 (t, J = 7.4 Hz, 2H), 1.58 (p, J = 15.2 Hz, 2H), 1.36 (h, J =
7.3 Hz, 4H), 0.84 (t, J = 7.3 Hz, 3H). 13C NMR (CDCl3, 100
MHz) δ (ppm) = 136.2, 130.3, 122.5, 120.3, 120.2, 111.2, 98.9,
32.6, 28.5, 22.7, 13.5. 77Se NMR (76 MHz, CDCl3) δ (ppm) =
1
g (92%); white solid; mp 117-120 ºC. H NMR (CDCl3, 400
MHz) δ (ppm) = 8.37 (br s, 1H); 7.59 (d, J = 7.9 Hz, 1H); 7.44-
7.40 (m, 2H); 7.25-7.20 (m, 3H); 7.17-7.05 (m, 4H). 13C NMR
(CDCl3, 100 MHz) δ (ppm) = 136.4, 132.0, 131.6, 131.2, 130.0,
129.7, 129.0, 123.1, 121.0 120.2 114.4, 98.0. 77Se NMR (76

6
464.5, 94.0.MS (Rel. Int.) m/z: 253 (21.3), 196 (17.3), 117 (100),
57 (3.6).
4.2.17. 1-methyl-3-(phenylthio)indole (5e):20a Yield: 0.196 g
ACCEPTED MANUSCRIPT
4.2.9. 1-methyl-3-(phenylselanyl)indole (3j):21g Yield: 0.244 g
1
(82%); white solid; mp 85-87 ºC. H NMR (CDCl3, 400 MHz) δ
(ppm) = 7.60 (d, J = 8.0 Hz, 1H); 7.35 (d, J = 8.0 Hz, 1H); 7.31-
7.22 (m, 2H); 7.18-7.07 (m, 5H); 7.05-6.96 (m, 1H); 3.78 (s, 3H).
13C NMR (CDCl3, 100 MHz) δ (ppm) = 139.7, 137.5, 135.0,
129.8, 128.6, 125.8, 124.6, 122.5, 120.5, 119.7, 109.7, 100.6,
33.0. MS (Rel. Int.) m/z: 238 (100), 223 (18.8), 222 (13.5), 196
(3.01), 77 (18.3).
1
(85%); white solid; mp 65-68 °C. H NMR (CDCl3, 400 MHz) δ
(ppm) = 7.62 (d, J = 7.9 Hz, 1H); 7.35 (d, J = 7.9 Hz, 1H); 7.29-
7.21 (m, 4H); 7.17-7.13 (m, 1H); 7.12-7.04 (m, 3H); 3.80 (s, 3H).
13C NMR (CDCl3, 100 MHz) δ (ppm) = 137.5, 135.6, 134.2,
130.7, 128.9, 128.6, 125.5, 122.4, 120.5, 120.4, 109.5, 96.1, 33.9.
77Se NMR (76 MHz, CDCl3) δ (ppm) = 464.5, 208.8. MS (Rel.
Int.) m/z: 286 (20.7), 207 (100), 130 (21.3), 91 (1.5), 77 (13.9).
4.2.10. 1-benzyl-3-(phenylselanyl)indole (3k):26b Yield: 0.345 g
4.2.18. 1-benzyl-3-(phenylthio)indole (5f):26e Yield: 0.226 g
1
(72%); yellow oil. H NMR (CDCl3, 400 MHz) δ (ppm) = 7.53
(d, J = 7.4 Hz, 1H); 7.28 (s, 1H); 7.25- 7.16 (m, 4H); 7.15-7.10
(m, 1H); 7.08-6.99 (m, 7H); 6.94 (td, J = 6.7 and 1.8 Hz, 1H);
5.21 (s, 2H). 13C NMR (CDCl3, 100 MHz) δ (ppm) = 139.5,
137.2, 136.6, 134.4, 130.0, 129.0, 128.7, 127.9, 128.0, 125.8,
124.7, 122.7, 120.7, 119.9, 110.2, 101.5. MS (Rel. Int.) m/z: 315
(86.7), 223 (100), 206 (3.5), 91 (84.6), 77 (14.7).
1
(95%); white solid, mp 77-79 °C. H NMR (CDCl3, 400 MHz) δ
(ppm) = 7.64 (d, J = 7.9 Hz, 1H); 7.34-7.24 (m, 4H); 7.24-7.20
(m, 3H); 7.17-7.10 (m, 6H); 7.39 (s, 1H); 5.35 (s, 2H). 13C NMR
(CDCl3, 100 MHz) δ (ppm) = 137.1, 136.7, 135.0, 134.1, 130.9,
128.9, 128.9, 128.6, 127.9, 127.0, 125.5, 122.6, 120.7, 120.6,
110.0, 97.0, 50.4. 77Se NMR (76 MHz, CDCl3) δ (ppm) = 464.5,
210.6. MS (Rel. Int.) m/z: 363 (10.7), 283 (42.3), 165 (15.4), 91
(100), 77 (7.5).
4.2.19. 2-methyl-3-(phenylthio)-1H-indole (5g):20a Yield: 0.207 g
(87%); brown solid; mp 110-111 ºC. 1H NMR (CDCl3, 400 MHz)
δ (ppm) = 8.10 (s, 1H); 7.53 (d, J = 7.8 Hz, 1H); 7.28 (d, J = 7.9
Hz, 1H); 7.24-7.07 (m, 4H); 7.07–6.87 (m, 3H); 2.45 (s, 3H).13C
NMR (CDCl3, 100 MHz) δ (ppm) = 141.1, 139.3, 135.4, 130.3,
128.7, 125.5, 124.5, 122.1, 120.7, 118.9, 110.6, 99.3, 12.1. MS
(Rel. Int.) m/z: 239 (18.9), 238 (100), 161 (22,3), 130 (13.7), 118
(20.7), 91 (5.3), 77 (14.5).
4.2.11. 2-methyl-3-(phenylselanyl)-1H-indole (3l):26c
Yield:
1
0.246 g (86%); white solid, mp 97-98 ºC. H NMR (CDCl3, 400
MHz) δ (ppm) = 8.13 (br s, 1H), 7.55 (d, J = 7.8 Hz, 1H), 7.28
(d, J = 7.9 Hz, 1H), 7.22 – 7.00 (m, 7H), 2.49 (s, 3H). 13C NMR
(CDCl3, 100 MHz) δ (ppm) = 140.8, 135.7, 133.9, 131.2, 128.9,
128.4, 125.3, 122.1, 120.6, 119.7, 110.5, 96.3, 13.1. 77Se NMR
(76 MHz, CDCl3) δ (ppm) = 464.5, 285.9. MS (Rel. Int.) m/z:
286 (20.9), 206 (100), 130 (54.3), 77 (15.7).
4.2.20. 3-methyl-2-(phenylthio)-1H-indole (5h):26f Yield: 0.177 g
(74%); white solid; mp 76-77 °C. H NMR (CDCl3, 400 MHz) δ
(ppm) = 7.89 (s, 1H); 7.58 (d, J = 8.0 Hz, 1H); 7.31-7.06 (m,
6H); 7.06-6.98 (m, 2H); 2.38 (s, 3H). 13C NMR (CDCl3, 100
MHz) δ (ppm) = 137.1, 136.9, 129.1, 128.5, 126.5, 125.7, 123.5,
121.5, 119.8, 119.6, 119.4, 110.9, 9.4. MS (Rel. Int.) m/z: 239
(100), 161 (17.4), 130 (21.7), 91 (5.4), 77 (19.4).
1
4.2.12. 3-methyl-2-(phenylselanyl)-1H-indole (3m):26b Yield:
1
0.218 g (76%); white solid; mp 136-138 ºC. H NMR (CDCl3,
400 MHz) δ (ppm) = 7.97 (br s, 1H); 7.58 (d, J = 7.9 Hz, 1H);
7.29-7.20 (m, 1H); 7.20-7.08 (m, 6H), 2.40 (s, 3H). 13C NMR
(CDCl3, 100 MHz) δ (ppm) = 137.6, 132.1, 129.3, 128.3, 126.4,
123.1, 119.8, 119.5, 119.3, 118.2, 110.7, 10.3. 77Se NMR (76
MHz, CDCl3) δ (ppm) = 464.5, 285.7. MS (Rel. Int.) m/z: 286
(43.2), 206 (100), 130 (66.9), 77 (95.4).
4.3 Procedure for preparation of 1-tolyl-3-(phenylselenyl)-
1H-indole (6a):35 An oven-dried resealable Schlenk tube was
charged with CuI (9,5 mg, 0.05 mmol, 5 mol%), 1.10-
phenanthroline (36 mg, 0.2 mmol, 20 mol%), Cs2CO3 (456 mg,
1.4 mmol), 1-iodo-4-metilbenzene (218 mg, 1 mmol), evacuated
and backfilled with argon. 3-(Phenylselenyl)-1H-indole (3a) (273
mg, 1 mmol) and DMF (1.0 mL) were added under argon. The
Schlenk tube was sealed and the reaction mixture was stirred at
110 °C for 24 h. The resulting suspension was cooled to room
temperature and filtered through a 0.5×1 cm pad of silica gel
eluting with EtOAc. The filtrate was concentrated under vacuum
and the crude product was purified by chromatography on silica
gel (2× 30 cm; hexane–EtOAc 95:5) affording 203 mg (56%
yield) of the compound as a pale brown oil.
4.2.13. 3-(phenylthio)-1H-indole (5a):26d Yield: 0.221 g (98%);
white solid; mp 150-151 ºC. 1H NMR (CDCl3, 400 MHz) δ
(ppm) = 8.41 (br s, 1H); 7.61 (d, J = 8.1 Hz, 1H); 7.49 (d, J = 2.6
Hz, 1H); 7.44 (d, J = 8.1 Hz, 1H); 7.28-7.26 (m, 2H); 7.18-7.05
(m, 6H). 13C NMR (CDCl3, 100 MHz) δ (ppm) = 139.2, 136.5,
130.6, 129.1, 128.7, 126.1, 125.6, 124.8, 124.1, 121.9, 120.9,
120.7. MS (Rel. Int.) m/z: 225 (100), 148 (14.8), 117 (1.8), 77
(23.6).
4.2.14. 3-((4-fluorophenyl)thio)-1H-indole (5b):26d Yield: 0.209 g
1
(86%); white solid; mp 133-134 ºC. H NMR (CDCl3, 400 MHz)
δ (ppm) = 8.30 (br s, 1H); 7.58 (dd, J = 8.0 Hz, 1H); 7.47-7.33
(m, 2H); 7.21-7.05 (m, 4H); 6.85 (t, J = 8.7 Hz, 1H). 13C NMR
(CDCl3, 100 MHz) δ (ppm) = 160.9 (d, J = 244.1 Hz); 136.5;
134.0 (d, J = 2.4 Hz); 130.4; 127.9 (d, J = 7.7 Hz); 122.0; 119.8;
119.5; 115.7 (d, J = 22.0 Hz); 111.6; 103.5; 102.6. MS (Rel. Int.)
m/z: 243 (100), 223 (4.8), 157 (2.8), 117 (6.4).
4.3.1. 1-tolyl-3-(phenylselenyl)-1H-indole (6a): Yield: 0.203 g
(56%); brown oil. H NMR (CDCl3, 400 MHz) δ (ppm) = 7.68
1
(d, J = 8.0 Hz, 1H); 7.57 (s, 1H); 7.53 (d, J = 8.2 Hz, 1H); 7.39
(d, J = 8.3 Hz, 2H); 7.31 (dd, J = 8.1, 1.5 Hz, 4H); 7.30-7.05 (m,
6H); 2.43 (s, 3H). 13C NMR (CDCl3, 100 MHz) δ (ppm) = 137.0,
136.9, 136.5, 134.5, 133.6, 131.1, 130.3, 129.0, 128.9, 125.7,
124.4, 123.1, 121.2, 120.7, 110.8, 98.9, 21.0. HRMS: Calculated
mass for C21H17NSe [M+]+: 363.0526, found: 363.0532.
4.2.15. 3-((3-(trifluoromethyl)phenyl)thio)-1H-indole (5c):14k
1
Yield: 0.246 g (84%); white solid, mp 130-132 ºC. H NMR
(CDCl3, 400 MHz) δ (ppm) = 8.48 (s, 1H); 7.57 (d, J = 8.0 Hz,
1H); 7.48 (d, J = 2.7 Hz, 1H ); 7.43 (d, J = 8.0 Hz, 1H); 7.40 (s, 1
H); 7.29-7.15 (m, 6H). 13C NMR (CDCl3, 100 MHz) δ (ppm) =
141.0; 136.6 131.06 (q, J = 31.6 Hz); 130.9; 129.0; 128.8 123 (q,
J = 272.4 Hz); 123.3; 122.4 (d, J = 4.2 Hz); 121.5 (d, J = 4.0 Hz);
121.2; 119.4; 111.7; 101.6. MS (Rel. Int.) m/z: 293 (100), 223
(20.4), 148 (23.9), 116 (3.6), 77 (15.3).
4.4 Procedure for preparation of 3-(phenyl)-1H-indole (6b):29
A mixture of 3-(butylselanyl)-1H-indole (0.25 mmol), Pd(PPh3)4
(0.1 equiv) and phenylboronic acid (1.2 equiv) were dissolved in
DMF (3 mL). After this, the Cu(OAc)2.H2O (1.2 equiv) was
added. This mixture was then heated in oil bath for 1 h at 80 °C.
After the reaction was cooled to room temperature, diluted with
AcOEt (3 mL) and then washed with saturated solution of NH4Cl
(20 mL). The organic phase was separated, dried over MgSO4
and concentrated under vacuum. The crude product was purified
by flash chromatography and eluted with hexane.
4.2.16. 3-((4-methoxyphenyl)thio)-1H-indole (5d):20a Yield: 0.256
1
g (75%); yellow solid; mp 112-113 °C. H NMR (CDCl3, 400
MHz) δ (ppm) = 8.36 (br s, 1H); 7.62 (d, J = 7.8 Hz, 1H); 7.39
(d, J = 2.6 Hz, 1H); 7.36 (d, J = 8.1 Hz, 1H); 7.27-7.17 (m, 1H);
7.16-7.09 (m, 3H); 6.72 (d, J = 8.8 Hz, 1H); 3.70 (s, 3H). 13C
NMR (CDCl3, 100 MHz) δ (ppm) = 157.8, 136.5, 130.0, 129.5,
129.0, 128.6, 122.8, 120.7, 119.6, 114.5, 111.5, 104.5, 55.30. MS
(Rel. Int.) m/z: 255 (100), 240 (38.5), 139 (3.9), 117 (2.5), 77
(11.4).
4.4.1. 3-phenyl-1H-indole (6b):36 Yield: 0.0226 g (47%); White
1
solid; mp 85-87 °C. H NMR (CDCl3, 400 MHz) δ (ppm) = 8.22
(s, 1H), 7.79 (d, J = 7.9 Hz, 1H), 7.71 (d, J = 7.6 Hz, 2H), 7.50-
7.44 (m, 3 H), 7.38 (d, J = 0.9 Hz, 1H), 7.31-7.27 (m, 4 H). 13C
NMR (CDCl3, 100 MHz) δ (ppm) = 136.7, 135.6 , 128.8, 127.5 ,

7
H.; Abdelazeem, A. H.; Ibrahim, H. M.; Salem, O. I.; Mohamed,
126.0, 125.8, 122.4, 121.7, 120.3, 120.0, 118.4, 111.4. MS (Rel.
ACCEPTED MANUSCRIPT
M. F.; Bukhari, S. N. A. Eur. J. Med. Chem. 2018
Shaw, S.; Bian, Z.; Zhao, B.; Tarr, J. C.; Veerasamy, N.; Jeon, K.;
Sensintaffar, J. L. J. Med. Chem. 2018 61, 2410-2421; (h) Pelz, N.
F.; Bian, Z.; Zhao, B.; Shaw, S.; Tarr, J. C.; Belmar, J.; Sensintaffar,
J. L. J. Med. Chem. 2016 59, 2054-2066; (i) Suzen, S. Curr. Org.
Chem. 2017 21, 2068-2076.
(a) Funk, C. D. Nat. Rev. Drug Discovery 2005
Kumar, A.; Agarwal, J. C.; Nath, C.; Gurtu, S.; Sinha, J. N.;
, 146, 260-273; (g)
Int.) m/z: 193 (100), 165 (24.6), 77 (3.4).
4.5 Procedure for preparation
of
1-benzyl-3-
(phenylselanyl)indole (3k):14u A mixture of 3a (0,3 mmol; 0,090
g), benzyl chloride (0,4 mmol; 0,050 g mmol), K2CO3 (0,3 mmol;
0,041), TBAB (30 mol%; 0,09 mmol; 0,029 g) and DMF (2 ml)
was stirred at room temperature for 2 h. At the end of this period,
the mixture was poured into cold-water (50 ml) and extracted
with EtOAc. The organic layer was separated, washed with a
saturated solution of NaHCO3 (10 ml), followed by brine (10 ml)
and dried over MgSO4. The solvent was evaporated to give the
crude product, and then purified by flash chromatography eluted
with hexane, affording 81 mg of desired product (74%); white
solid, mp 77-79 °C.).26b
,
,
,
6
7
, 4, 664-672; (b)
Bhargava, K. P.; Shanker, K. J. Heterocyclic Chem. 1981, 18, 1269-
1271.
(a) Abraham, R.; Prakash, P.; Mahendran, K.; Ramanathan, M.
Microb. Pathogenesis 2018 114, 409-413; (b) Unangst, P. C.;
Connor, D. T.; Stabler, S. R.; Weikert, R. J.; Carethers, M. E.;
Kennedy, J. A.; Thueson, D. O.; Chestnut, J. C.; Adolphson, R. L.;
,
,
Conroy, M. C. J. Med. Chem. 1989
(a) Zoraghi, R.; S. Campbell, S.; Kim, C.; Dullaghan, E. M.; Blair, L.
M.; Gillar, R. M.; Sperry, J. Bioorg. Med. Chem. Lett 2014 24
5059-5062; (b) Daly, S.; Hayden, K.; Malik, I.; Porch, N.; Tang, H.;
Rogelj, S.; Magedov, I. V. Bioorg. Med. Chem. Lett. 2011 21, 4720-
, 32, 1360-1366.
8
Acknowledgements
.
,
,
This study was financed in part by the Coordenação de
Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES)
– Finance Code 001, CNPq Process: 400400/2016-2, Fundação
Araucária and UFPR.
,
4723; (c) Nandakumar, A.; Thirumurugan, P.; Perumal, P. T.;
Vembu, P.; Ponnuswamy, M. N.; Ramesh, P. Bioorg. Med. Chem.
Lett. 2010, 20, 4252-4258; (d) La Regina, G.; Bai, R.; Rensen, W. M.;
Di Cesare, E.; Coluccia, A.; Piscitelli, F.; Famiglini, V.; Regio, A.;
Nalli, M.; Pelliccia, S.; Da Pozzo, E.; Costa, B.; Granata, I.; Porta, A.;
Maresca, B.; Soriani, A.; Iannitto, M. L.; Santoni, A.; Li, J.; Cona, M.
M.; Chen, F.; Ni, Y.; Brancale, A.; Dondio, G.; Vultaggio, S.; Varasi,
M.; Mercurio, C.; Martini, C.; Hamel, E.; Lavia, P.; Novellino, E.;
Silvestri, R. J. Med. Chem. 2013, 56, 123-149.
(a) Campbell, J. A.; Bordunov, V.; Broka, C. A.; Browner, M. F.;
Kress, J. M.; Mirzadegan, T.; Villasenor, A. Bioorg. Med. Chem. Lett.
References and Notes
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