Structure-activity relationship studies of the tricyclic indoline resistance-modifying agent

Article abstract of DOI:10.1021/jm500146g

Previously we discovered a tricyclic indoline, N-[2-(6-bromo-4-methylidene- 2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (1, Of1), from bioinspired synthesis of a highly diverse polycyclic indoline alkaloid library, that selectively resensitizes methicillin-resistant Staphylococcus aureus strains to β-lactam antibiotics. Herein, we report a thorough structure-activity relationship investigation of 1, which identified regions of 1 that tolerate modifications without compromising activity and afforded the discovery of a more potent analogue with reduced mammalian toxicity.

Full text of DOI:10.1021/jm500146g

Article
pubs.acs.org/jmc
Structure−Activity Relationship Studies of the Tricyclic Indoline
Resistance-Modifying Agent
Le Chang, Jessica D. Podoll, Wei Wang, Shane Walls, Courtney P. O’Rourke, and Xiang Wang*
Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
ABSTRACT: Previously we discovered a tricyclic indoline, N-
[2-(6-bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-carba-
zol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (1, Of1), from
bioinspired synthesis of a highly diverse polycyclic indoline
alkaloid library, that selectively resensitizes methicillin-resistant
Staphylococcus aureus strains to β-lactam antibiotics. Herein, we
report a thorough structure−activity relationship investigation
of 1, which identified regions of 1 that tolerate modifications
without compromising activity and afforded the discovery of a
more potent analogue with reduced mammalian toxicity.
MRSA, strains that are resistant to these last-line-of-defense
treatments have already become a problem of their own.8
Resistance-modifying agents (RMAs) offer a promising
solution.9 These target nonessential, resistance-conferring
genes and restore antibiotic sensitivity. A notable advantage
of RMAs is that they are capable of extending the market
lifespan of known antibiotics that have already been optimized
for large-scale production with well-studied toxicity profiles. For
example, clavulanic acid is a serine β-lactamase inhibitor that is
commonly used in combination with amoxicillin, under the
brand name Augmentin, among others, to treat infections
resulting from β-lactamase-producing bacteria.10 Clavulanic
acid deactivates β-lactamase by irreversibly acylating the
catalytic serine residue in the active site of the β-lactamase
enzyme that would otherwise function to breakdown the β-
lactam antibiotic. Although the clavulanic acid/β-lactam
combination is effective for serine β-lactamases, it is ineffective
against metallo-β-lactamases and does nothing to combat β-
lactam resistance mediated by PBP2a.11Although efforts have
been underway to discover more novel RMAs, thus far, only
those that are β-lactamase inhibitors have been successfully
brought to market. β-Lactam antibiotics are one of the most
widely used antibiotics and have inspired numerous research
efforts to overcome bacterial resistance. In addition to β-
lactamase inhibitors, other classes of compounds have been
reported to potentiate the activity of β-lactam antibiotics, such
as compounds interfering bacterial cell wall synthesis and
compounds affecting resistance-sensing pathways.12−15
INTRODUCTION
■
Antibiotic resistance is an urgent world health concern that is
aggravated by a lack of novel antibiotic discovery.1 The vast
majority of antibiotic classes on the market today were
discovered between 1940 and 1960, a period of time known
as “the golden era” of antibiotic discovery.2 Since this time,
however, only two new classes of antibiotics have been brought
to the clinic. Microbial antibiotic resistance has prompted the
pharmaceutical industry to develop analogues of known
antibiotics; however, bacteria have been observed to develop
resistant phenotypes quickly, and there are not currently
enough analogues in the antibiotic pipeline to combat
imminent resistance emergence.3 Methicillin-resistant Staph-
ylococcus aureus (MRSA) is particularly concerning in this
regard. Prior to the introduction of penicillin in the 1940s, the
mortality of patients who developed invasive staphylococcus
infections was nearly 80%, but this statistic was drastically
reduced by the introduction of penicillin in the clinic.4 In just a
few years, however, resistance to penicillin, mediated by β-
lactamases, emerged, which led to the introduction of β-lactam
antibiotics such as methicillin, which are resistant to
degradation by β-lactamase. It was not long, however before
S. aureus developed methicillin resistance in the form of
alternative penicillin binding proteins (PBPs), such as PBP2a.5
In addition to methicillin resistance, a number of MRSA strains
have developed resistant phenotypes against multiple drugs
used in the clinic, thus limiting treatment options for bacterial
infections and threatening the onset of a postantimicrobial era.6
Of the estimated 2 million illnesses and 23 000 deaths last year
that are directly associated with antibiotic resistant bacteria in
the United States, MRSA was directly responsible for 80 000
illnesses and 11 000 deaths.7 Although vancomycin as well as
some antibiotic analogues are still effective for the treatment of
Recently, our group discovered a tricyclic indoline, 1, with
RMA activity against MRSA that selectively potentiates a
variety of β-lactam antibiotics.16 Interestingly, in addition to β-
Received: January 27, 2014
Published: April 2, 2014
© 2014 American Chemical Society
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lactam antibiotics that are susceptible to breakdown by β-
lactamase, 1 also potentiates those that are β-lactamase
resistant, such as methicillin, oxacillin, and meropenem.
Intrigued by the unique activity of 1, we sought to conduct a
structure−activity relationship (SAR) study in order to identify
regions of the structure of 1 that may be modified to improve
its activity and toxicity profile, as well as to allow synthesis of
functional analogues to facilitate the discovery of the cellular
target of 1. Herein, we report a thorough SAR study of our
previously reported tricyclic indoline RMA, 1.
We began our SAR investigation by testing a number of
functional group modifications to the indoline and sulfonamide
nitrogens of 1. Due to the different pKa, different bases were
used in the functionalization steps. As shown in Scheme 1, for
Scheme 1. Functionalization of the Indoline and
a
Sulfonamide Nitrogens
RESULTS AND DISCUSSION
Modification of 1. In order to conduct our SAR
investigation of 1 (Figure 1), we synthesized several series of
■
a
Reagents and conditions: (a) R1X, K2CO3, 0 °C, CH3CN; (b) for 1d,
NaH 0 °C, then MeI, 0−60 °C, DMF; for 1e,f, R2X, Et3N, 0 °C, DCM.
compound 1a, selective methylation was carried out in the
presence of potassium carbonate in anhydrous CH3CN;
compounds 1b and 1c were prepared with corresponding
electrophilic reagents under similar condition. While compound
1d was generated by using sodium hydride as a base,
triethylamine was employed to activate the sulfonamide
nitrogen selectively for the preparation of analogues 1e and
1f. We observed that when either or both of these moieties are
modified, the RMA activity of the compound is abolished
(Table1). We thus concluded that both these nitrogens must
not be modified.
Figure 1. The structure of 1.
1 analogues, which were then evaluated for their ability to
resensitize MRSA to a collection of β-lactam antibiotics. For
these activity tests, we chose to use amoxicillin in combination
with clavulanic acid (a.k.a., Augmentin, one of the top three
most prescribed antibiotics), cefazolin (a first-generation
cephalosporin), and meropenem (an ultrabroad-spectrum
carbapenem). Amoxicillin/clavulanic acid and cefazolin resensi-
tizing experiments were performed using MRSA ATCC BAA-
44, for which the MICs of these two antibiotics were found to
be 32/16 and 128 μg/mL, respectively. Experiments using
meropenem were performed using MRSA ATCC 33592, since
this strain has demonstrated greater level of resistance to
meropenem, with an MIC of 16 μg/mL. To assess activity of
each analogue as RMA, we employed a modified broth
microdilution assay, as described previously.16 Briefly, this
involves incubating MRSA with 1 or each of its analogues in 2-
fold serial dilution in the presence of each individual antibiotic
at its Clinical Laboratory Standards Institutes (CLSI)-defined
sensitive concentrations. For amoxicillin/clavulanic acid, this
concentration was 4/2 μg/mL (8-fold potentiation); for
cefazolin, 8 μg/mL (16-fold potentiation); and for meropenem,
4 μg/mL (4-fold potentiation).17 Following overnight
incubation, plates were examined for bacterial growth, or lack
thereof. Analogues of 1were tested at concentrations ranging
from 0.5 to 32 μg/mL. The minimum resensitizing
concentration (MRC) was defined as the concentration of 1’s
analogues at which no overnight growth was observed in the
presence of a sensitive concentration of antibiotic. Compounds
that displayed similar or improved RMA activity relative to 1
were further tested for their toxicity against the growth of
human cervical adenocarcinoma HeLa cells by incubating a
range of concentrations of each compound with cells for 24 h
and assessing viability at each concentration using the CellTiter
Glo mammalian viability assay (Promega). The half growth
inhibitory concentration (GI50) of each analogue was
determined by fitting the data using KaleidaGraph (v4.1.1,
Synergy Software).
Modifications of the Aromatic Substitution of Indo-
line. We next sought to modify the aromatic portion of the
indoline ring. To prepare these analogues, we adapted the
three-step synthetic route that we previously used for synthesis
of the original library. As depicted in Scheme 2, cyclic imine 2
was reacted with different aryl hydrazines 3 and 4-
chlorobenzenesulfonyl chloride to afford the alkynyl indole
product 4 using a modified Fischer indole synthesis protocol.18
Cyclization under our standard gold catalysis conditions (5
mmol % Ph3PAuNTf2)19 followed by a reductive ring-opening
reaction afforded a series of 1 analogues (6a−l). In order to test
the necessity of the bromine (R2) at the 5-position of the
indoline, we synthesized analogues replacing it with a methyl
group (6b), a methoxy group (6c), or a hydrogen (6e). In the
case of each of these modifications, RMA activity was abolished
or greatly diminished for all three antibiotics tested. Moving the
bromine to other positions on the indoline (e.g., 6i, 6h, and 6g)
also significantly reduced its RMA activity. We thus concluded
that the presence of a halogen at the R2 position is necessary for
RMA activity. We further evaluated whether the identity of the
halogen at the R2 position affects its activity. We found that
RMA activity is optimal when bromine is maintained as the R2
halogen. However, although replacing the R2 bromine with
chlorine (6a) reduced RMA activity somewhat, this analogue
also showed significantly reduced toxicity against mammalian
cells (Table 2). In addition, we also synthesized several 1
analogues with an additional halogen at the 7-position of
indoline. We found that when the R2 halogen is chlorine,
fluorine at R4 significantly reduces RMA activity (6j); however,
when the identity of both R2 and R4 are chlorine (6k), the
RMA activity remains similar to that of 1. Maintaining bromine
at the R2 position and adding fluorine at R4 (6l), however, yield
slightly improved RMA activity and reduced mammalian
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Table 1. MRC Values for Indoline and Sulfonamide Nitrogen Modifications
ab
,
ab
,
ac
,
entry
compd
R1
R2
amox/clav
cefazolin
meropenem
1
2
3
4
5
6
1a
1b
1c
1d
1e
1f
Me
H
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
>32
SO2PhpCl
H
COPhpCl
H
H
H
H
Me
SO2PhpCl
COPhpCl
a
b
c
All MRC values are in μg/mL. MRSA ATCC BAA-44. MRSA ATCC 33592.
a
amine products 11a,b were further functionalized to afford
compounds 12a−n and 13a−m. In addition, analogue 12o was
prepared by the reduction of 12n with zinc dust in the presence
of ammonium chloride.21 We first discovered that removing the
side chain (R2) entirely resulted in severely reduced activity in
the presence or absence of the R1 fluorine (11a,b). Likewise,
replacing the sulfonamide with an amide (e.g., 12a−c) resulted
in abolished RMA activity. We discovered the necessity of the
phenyl ring by replacing it with a pyridine ring (12m), which
resulted in a loss of RMA activity. We next attempted to modify
the side chain phenyl ring. When the chlorine at the para
position relative to the sulfonamide was removed from 1, the
RMA activity is reduced at least 2-fold (12d). We thus
attempted to modify the phenyl ring on the side chain with a
series of functional groups. For these experiments, we
synthesized analogues in which the chlorine was maintained
and an additional chlorine was added to the meta or ortho
position, respectively (12i,j). These disubstituted products did
not result in improved RMA activity; however, in the presence
of the fluorine at the 7-position of indoline (R1), reduced
toxicity was observed for the disubstituted analogue 13f. The
remainder of our modifications focused on the para position of
the phenyl ring. Replacing the chlorine with a fluorine (i.e., 12f)
abolished RMA activity entirely; however, this same mod-
ification in combination with the R1 as a fluorine (i.e., 13c)
resulted in similar RMA activity relative to 1. A similar trend
was also observed when the chlorine was replaced with an
iodine in the absence (12h) or presence (13e) of the R1
fluorine. Interestingly, when the chlorine is replaced with a
methyl group (12e), RMA activity is lost; however, it is
regained when fluorine is added at the R1 position (13b). In
addition, the mammalian toxicity of this analogue is reduced in
this case. This trend was also observed when the chlorine was
replaced with a cyanide (12k, 13h). Although substituting a
methoxy group for the chlorine in the presence of the R1
fluorine (13a) results in slightly reduced activity, the
mammalian toxicity is significantly reduced. Likewise, replacing
the chlorine with a bromine (12g) resulted in slightly reduced
RMA activity, and this analogue demonstrated a significant
decrease in mammalian toxicity (Table 3). Intriguingly, when
we added the R1 fluorine (13d) to this molecule, we observed a
significant (at least 4-fold) increase in RMA activity as well as
decreased toxicity relative to 1.
Scheme 2. Synthesis of 6a−l
a
p
Reagents and conditions: (a) ClPhSO2Cl, DMAP, 23 °C, 0.5 h,
DMF; 2, 0.5 h; MsOH, then 3, 60−120 °C, 20 h; (b) Ph3PAuNTf2, 50
°C, toluene, 1−12 h; (c) AcOH, NaBH3CN, MeOH, 0 °C, 0.5 h.
[Ph3PAuNTf2
(triphenylphosphine)gold(I).]
= [bis(trifluoromethanesulfonyl)imidate]-
toxicity with respect to 1. On the basis of this series of
modifications on the aromatic indoline ring, we concluded that
in order to maintain RMA activity, the identity of the R2
position must be a halogen (bromine or chorine) and that the
R2 position may be functionalized with a second halogen to
improve or maintain activity.
Modifications of the Side Chain. We next attempted to
conduct SAR investigations on the side chain of 1. For this
portion of our SAR investigation, we maintained the bromine
group at the 5-position of the indoline moiety. We included
several analogues in this portion of our study with fluorine at
the 7-position of indoline, since 6l showed similar activity but
lower mammalian cytotoxicity with respect to 1 (Table 2). The
general synthetic route (Scheme 3) was similar to Scheme 2.
For this series of 1 analogues, benzyl chloroformate was used as
the active reagent in the indole synthesis step, which was
removed successfully by treating ring-opening products 10a,b
with boron trifluoride−dimethyl sulfide.20 The resulting free
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Table 2. MRC and GI50 Values for the Substitutions of Indoline Aromatic Ring
ab
,
ab
,
ac
,
d
entry
compd
R1
R2
R3
R4
amox/clav
cefazolin
meropenem
GI50
1
2
1
H
H
H
H
H
H
H
H
H
Br
H
H
H
Br
Cl
Me
MeO
F
H
H
H
H
H
H
H
H
H
H
H
H
4
4
4
17.1
35
−
−
−
−
−
−
−
6a
6b
6c
6d
6e
6f
8
4
8
3
16
>32
16
16
>32
>32
16
32
16
4
16
>32
16
16
>32
32
16
16
16
4
32
>32
16
16
>32
8
4
5
6
H
7
H
phenylene
8
6g
6h
6i
H
H
Br
H
H
H
H
Br
H
H
F
9
H
16
16
32
4
10
11
12
13
H
−
−
13.6
6j
Cl
Cl
Br
6k
6l
Cl
F
2
4
4
18.1
a
b
c
d
MRC values are in μg/mL. MRSA ATCC BAA-44. MRSA ATCC 33592. HeLa cells; GI50 values are in μg/mL.
a
Scheme 3. Synthesis of 12a−n and 13a−i
tested. Since 13d exhibited no antiproliferative effect on its
own, we decided to confirm its synergistic activity with the
three antibiotics tested in this report by performing the
checkerboard (CB) test for synergy and calculating the
fractional inhibitory concentration index (FICI) for each
antibiotic tested in combination with 13d. CB assays and
FICIs were set up and calculated as described previously.23
Briefly, 13d was diluted across 96-well microplates in MHB (8
to 0.016 μg/mL), and to each plate either amoxicillin/
clavulanic acid (128 to 1 μg/mL), cefazolin (128 to 1 μg/
mL), or meropenem (16 to 0.125 μg/mL) was diluted down
the plate. Thusly, each well of the 96-well plate contained a
unique concentration combination of 13d and antibiotic. FICI
was calculated by the following formula: FICI = FICA + FICB,
where FICA is the MIC of drug A in combination with B
divided by the MIC of drug A on its own, and FICB is the MIC
of drug B in combination divided by the MIC of drug B on its
own. An FICI that is less than 0.5 indicates a synergistic drug
interaction, an FICI in the range of 0.5−1 denotes an additive
drug interaction, and an FICI greater than 1 indicates an
antagonistic interaction. The FICI values of 13d for
amoxicillin/clavulanic acid, cefazolin, and meropenem were
0.0315, 0.0156, and 0.0315, respectively. This result confirms
the synergistic action of 13d in combination with all antibiotics
tested in this study.
a
Reagents and conditions: (a) CbzCl, DMAP, 23 °C, 0.5 h, DMF; 2,
2−12 h; MsOH, then 3, 60−120 °C; (b) Ph3PAuNTf2, 50 °C, toluene,
1−12 h; (c) AcOH, NaBH3CN, MeOH, 0 °C, 0.5 h; (d) BF3·Et2O,
Me2S, DCM, 23 °C, 1.5 h; (e) R2X, Et3N, DCM, 0 °C, 0.5−2 h.
Evaluation of the Synergistic Activity and Hemolytic
Activity of 13d. In order to assess the synergistic nature of
13d, we first investigated the antibacterial activity of 13d
against both MRSA and methicillin-sensitive S. aureus (MSSA)
strains. For this experiment, we employed a standard
microdilution assay using MRSA ATCC BAA-44, MRSA
ATCC 33592, and MSSA ATCC 25923. The assay was
performed by following the procedure outlined by CLSI.22 The
minimum inhibitory concentrations (MICs) of 13d against all
strains was higher than 64 μg/mL, the highest concentration
We further evaluated the toxicity of 13d by conducting a
standard hemolytic assay as previously described.24,25 This
assay measures the amount of hemoglobin leakage in
compound-treated human red blood cells (hRBCs) and is
used to measure the amount of membrane damage induced by
drug treatment. The hemolytic activity assay was conducted for
multiple concentrations of 13d. It caused less than 2%
hemolysis of red blood cells at 64 μg/mL (64-fold above its
MRC), the highest concentration tested. We thus concluded
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Table 3. MRC and GI50 Values for 1 Analogues with Modifications on the Side Chain
ab
,
ab
,
ac
,
d
entry
compd
R1
R2
amox/clav
cefazolin
meropenem
GI50
1
2
1
H
H
F
SO2PhpCl
4
4
4
17.1
−
16.2
11a
11b
12a
12b
12c
12d
12e
12f
12g
12h
12i
12j
12k
12l
H
32
>32
>32
>32
>32
8
32
32
>32
>32
>32
8
32
16
32
32
>32
16
>32
>32
8
3
H
4
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
F
TFA
−
−
−
−
−
−
40
33
12.8
−
5
COBu
COPhpCl
6
7
SO2Ph
8
SO2PhpMe
SO2PhpF
SO2PhpBr
SO2PhpI
SO2Ph3,4Cl
SO2Ph2,4Cl
SO2PhpCN
SO2PhpNHAc
>32
>32
4
>32
>32
4
9
10
11
12
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
29
4
4
32
4
4
2
8
>32
8
4
16
>32
32
>32
16
8
16
32
32
>32
16
8
−
−
−
−
>32
32
>32
16
4
5
12m
12n
12o
13a
13b
13c
6l
SO2 Py
SO2PhpNO2
SO2PhpNH2
SO2PhpOMe
SO2PhpMe
SO2PhpF
−
49
22
18.3
18.1
22
19.6
31
32
17.0
8.7
F
4
4
4
F
4
4
4
F
SO2PhpCl
2
4
4
13d
13e
13f
13g
13h
13i
F
SO2PhpBr
1
1
1
F
SO2PhpI
4
2
4
F
SO2Ph3,4Cl
SO2PhpNHAc
SO2PhpCN
4
4
4
F
32
8
32
4
16
4
F
F
SO2PhpCF3
4
4
4
a
b
c
d
MRC values are in μg/mL. MRSA ATCC BAA-44. MRSA ATCC 33592. HeLa cells; GI50 values are in μg/mL.
that compound 13d shows an insignificant level of toxicity
against hRBCs.
of the indoline increases RMA activity of the compound in
multiple instances, including those in which another
modification has reduced or eliminated RMA activity.
Furthermore, we discovered that a number of substitutions
may be added to the phenyl ring on the side chain, which will
allow the development of additional 1 analogues for the
discovery of its cellular target, a stepping stone to under-
standing the β-lactam resistome.26 In addition, we have
discovered a more potent analogue of 1, compound 13d,
with reduced mammalian toxicity and low hemolytic activity.
We were able to confirm the synergistic activity of 13d by
calculating its FICI and showed that it is highly synergistic in
combination with all antibiotics tested. Further investigation of
the mode of action of 1 and evaluation of its efficacy in vivo are
ongoing and will be reported in due course.
Collectively, these results indicate that 13d is a more potent
analogue of 1, with increased RMA activity, decreased toxicity,
and potent synergy with multiple classes of β-lactam antibiotics.
Furthermore, 13d shows no antiproliferative effect against
MRSA or MSSA on its own.
CONCLUSIONS
■
We have synthesized a number of structural analogues of our
tricyclic indoline RMA, 1, by taking advantage of the previously
developed highly efficient synthetic approach with high
functional group tolerance. These new analogues have been
evaluated for their ability to potentiate three representative β-
lactam antibiotics (amoxicillin/clavulanic acid, cefazolin, and
meropenem) in MRSA and for their toxicity in mammalian
cells. We found that neither the aniline nor the sulfonamide
nitrogen can tolerate further modification. While the
sulfonamide group on the side chain is crucial for the RMA
activity, modifications of both aromatic systems can further
fine-tune the RMA activity and the mammalian toxicity.
Notably, we discovered that adding fluorine to the 7-position
EXPRIMENTAL SECTION
■
Bacterial Strains. Strains ATCC BAA-44 (MRSA) and ATCC
25923 (MSSA) were gifts from the laboratories of Daniel Feldheim
and Charles McHenry, respectively. Strain ATCC 33592 (MRSA) was
purchased from ATCC (http://www.atcc.org).
Minimal Resensitizing Concentration (MRC) Determination.
MRC screens were performed as described previously.16 Briefly,
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antibiotic MIC values where S. aureus is considered susceptible were
determined from the CLSI handbook supplement.17 Analogues of 1
were diluted to 5 mg/mL in DMSO. Antibiotic was prepared at twice
the intended final concentration in Mueller−Hinton broth (MHB).
For amoxicillin/clavulanic acid, the initial concentration was 8/4 μg/
mL; for meropenem, 8 μg/mL; and for cefazolin, 16 μg/mL. A 50 μL
portion of the antibiotic containing media was added to each well of
96-well plates, and 100 μL was added to the top row. A 1.28 μL
portion of of 5 mg/mL alkaloid solution was added to the top row of
each plate to afford a concentration of 64 μg/mL in the top row of
each plate, and 2-fold serial dilutions were performed down the
columns. Once the plates were prepared, a day culture of MRSA was
diluted to OD600 0.002, and 50 μL was added to each well. The final
concentration of MRSA added was OD600 0.001, the final
concentration of amoxicillin/clavulanic acid was 4/2 μg/mL, the
final concentration of meropenem was 4 μg/mL, the final
concentration of cefazolin was 8 μg/mL, and the highest concentration
of 1 analogue tested was 32 μg/mL. Plates were incubated overnight at
37 °C with shaking. The MRC value was determined as the
concentration of 1 analogue in the presence of antibiotic at which
there was no observable overnight growth.
Microdilution Tests for Minimal Inhibitory Concentration
(MIC) Determination. The minimal inhibitory concentrations
(MICs) of active 1 analogues were determined by the broth
microdilution method detailed in the CLSI handbook.22 All
antimicrobial compounds were purchased from Sigma-Aldrich. The
growth media used for all MIC experiments was MHB purchased from
HIMEDIA through VWR (cat. 95039-356). The inoculum was
prepared by diluting a bacterial day culture (OD600 0.15−0.4) to
OD600 0.002. This dilution was further diluted 2-fold when added to
96-well microplates (USA Scientific CytoOne 96-well TC plate, cat.
CC7682-7596) for a final inoculum concentration of OD600 0.001. All
plates were incubated at 37 °C with shaking for 18 h before results
were interpreted.
Microdilution Checkerboard Tests for Drug Synergy.
Checkerboard assays were performed as described previously.23
Antibiotics were diluted down the columns of a 96-well microplate,
while 13d was diluted across the rows. Plates were prepared that
contained concentrations of antibiotics and 13d 2-fold higher than the
intended final concntrations and were prepared in duplicate. All
antimicrobial compounds were purchased from Sigma-Aldrich. The
growth media was MHB purchased from HIMEDIA through VWR
(cat. 95039-356). The inoculum was prepared by diluting a bacterial
day culture (OD600 0.15−0.4) to OD600 0.002. This dilution was
further diluted 2-fold when added to 96-well microplates (USA
Scientific CytoOne 96-well TC plate, cat. CC7682-7596) for a final
inoculum concentration of OD600 0.001. All plates were incubated at
37 °C with shaking for 18 h before results were interpreted.
Mammalian Cytotoxicity of 1 Analogues in HeLa Cells. To
evaluate the cytotoxicity of 1 in mammalian cells, a cell viability assay
was carried out using a CellTiter-Glo luminescent cell viability assay
kit (Promega). Human cervixcal adenocarcinoma HeLa cells were
seeded on white, cell-culture-treated, 96-well plates (Corning 3917)
with Dulbecco’s modified Eagle’s medium (DMEM) supplemented
with 10% fetal calf serum (FCS), 1% penicillin/streptomycin, at the
densities of 20 000 cells/well. The medium volume for each well was
100 μL. Cells were incubated at 37 °C in 5% CO2/95% air for 16 h.
The medium was removed from each well and replaced with 99 μL of
warmed, fresh medium. To each well, 1 μL of 1 analogue was added in
DMSO to final concentrations of 0.5−32 μg/mL. Each series was
performed in triplicate. After incubation at 37 °C for another 24 h, the
plates were equilibrated to room temperature for 30 min, and 100 μL
of CellTiter-Glo reagent (Promega) was added to each well and mixed
for 2 min on an orbital shaker. The plate was incubated at room
temperature for another 10 min to stabilize the luminescent signal.
The luminescence of each sample was recorded with an Envision
Multilabel Plate Reader (PerkinElmer).
(hRBCs) were washed with 8 mL of D-PBS three times or until the
supernatant was clear. hRBCs were then resuspended in 80 mL of D-
PBS. This was further diluted in D-PBS to a final concentration of 1%
of the original pellet volume. 13d was dissolved in DMSO and to 1 mL
samples of the hRBC solution to final concentrations of 64, 16, and 4
μg/mL. A 1% Triton X-100 sample was used as the positive control;
this was considered to produce 100% hemolysis. DMSO alone was
used as the negative control. The mixtures were vortexed gently and
incubated at 37 °C for 1 h with shaking. The mixtures were then
centrifuged at 3000 rpm for 10 min, and 50 μL of supernatant from
each sample was transferred to a well of a sterile 96-well plate
containing 50 μL of water. The presence of hemoglobin was measured
by absorbance at 415 nm, and the percent hemolysis was calculated
using the following equation:
(A415,13d − A415,DMSO
(A415,complete hemolysis − A415,DMSO
)
%hemolysis =
× 100
)
Each condition was assayed in triplicate. The assay was performed
within 3 h of the blood draw.
Chemistry. Unless otherwise noted, reagents were obtained
commercially and used without further purification. CH2Cl2 was
distilled from CaH2 under a nitrogen atmosphere. THF was distilled
from sodium−benzophenone under a nitrogen atmosphere. Toluene
was distilled from sodium under a nitrogen atmosphere. Thin-layer
chromatography (TLC) analysis of reaction mixtures was performed
on Dynamicadsorbents silica gel F-254 TLC plates. Flash chromatog-
raphy was carried out on Zeoprep 60 ECO silica gel. 1H and 13C NMR
spectra were recorded with Varian INOVA (400, 500 MHz) and
Bruker Avance-III (300 MHz) spectrometers. Mass spectral and
analytical data were obtained via the PE SCIEX/ABI API QSTAR
Pulsar iHybrid LC/MS/MS (Applied Biosystems) operated by the
Central Analytical Laboratory, University of Colorado at Boulder.
Infrared (IR) spectra were recorded on a Thermo Nicolet Avatar 370
FT-IR spectrometer. Melting point (mp) determinations were
performed by using a Thomas-Hoover capillary melting point
apparatus and are uncorrected. Compound purity (≥95%) was
confirmed on the basis of the integration of the area under the UV
absorption curve at λ = 254 or 210 nm signals using an Agilent 1260
series HPLC system coupled with a 6120 Quadrupole mass
spectrometer (column: ZORBAX Narrow Bore SB-C18 RRHT, 2.1
× 50 mm, 1.8 μm, PN 827700-902). The system was eluted at 0.5 mL/
min with a gradient of water/acetonitrile with 0.1% formic acid: 0−5
min, 5−95% acetonitrile; 5−7 min, 95% acetonitrile; 7−7.25 min, 95−
5% acetonitrile; 7.25−8.5 min, 5% acetonitrile.
General Protocol for the One-Pot Three-Component Indole
Synthesis. The activating agent 4-chlorobenzenesulfonyl chloride
(1.2 equiv) was added to a solution of 4-dimethylaminopyridine (1.2
equiv) in anhydrous DMF at 0 °C. The reaction was stirred at 23 °C
for 30 min. A solution of the alkynyl imine 2 (1.0 equiv) in anhydrous
DMF was added and the reaction was stirred at the same temperature
for 0.5 h. Then methanesulfonic acid (3.0 equiv) was next added to the
above mixture at 0 °C. The reaction was then stirred at 23 °C for 2 h.
Arylhydrazine 3 (1.5 equiv) was added and the mixture stirred for an
addition 1 h at 23 °C. The reaction was then heated to 60−120 °C (60
°C for electron-rich arylhydrazines and 120 °C for electron-poor
arylhydrazines for 20 h). The reaction was cooled down to room
temperature. The residue was then dissolved in ethyl acetate and
washed with brine and a saturated aqueous solution of sodium
bicarbonate. The combined organic layers were dried over anhydrous
Na2SO4, filtered, and concentrated in vacuo to give a crude product,
which was purified by column chromatography on silica gel to give the
indole product 4. 4-Chloro-N-{2-[5-chloro-2-(pent-4-yn-1-yl)-1H-
indol-3-yl]ethyl}benzene-1-sulfonamide (4a): TLC (hexanes:ethyl
1
acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 32%; H NMR (500
MHz, CDCl3) δ 7.99 (s, 1H), 7.66 (d, J = 8.6 Hz, 2H), 7.41 (d, J = 8.6
Hz, 2H), 7.24 (d, J = 2.0 Hz, 1H), 7.21 (d, J = 8.5 Hz, 1H), 7.10 (dd, J
= 8.6, 2.0 Hz, 1H), 4.40 (t, J = 6.2 Hz, 1H), 3.25 (q, J = 6.5 Hz, 2H),
2.89 (dt, J = 16.4, 7.1 Hz, 4H), 2.23 (td, J = 6.8, 2.7 Hz, 2H), 2.09 (t, J
= 2.6 Hz, 1H), 1.85 (p, J = 7.1 Hz, 2H); 13C NMR (75 MHz, CDCl3)
Hemolytic Activity Assay. Eight milliliters of freshly drawn,
heparin-stabilized, human blood was centrifuged at 3500 rpm for 5
min. The supernatant was removed and the human red blood cells
3808
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δ 139.1, 138.1, 137.4, 133.7, 129.3, 129.0, 128.3, 125.3, 121.8, 117.3,
111.6, 107.1, 83.5, 69.9, 43.0, 28.2, 24.5, 24.5, 17.7; HRMS (ESI) m/z
calcd for C21H21Cl2N2O2S [M + H]+ 435.0695, found 435.0694; IR
(thin film) 3377, 3297, 2924, 2854, 2359, 1575, 1475, 1325, 1160,
1094, 828 cm−1.
111.6, 110.2, 65.6, 52.5, 39.3, 39.0, 32.3, 29.7, 27.6, 22.0; HRMS (ESI)
m/z calcd for C15H20BrN2 [M + H]+ 307.0804, found 307.0811; IR
(thin film) 3367, 2960, 2924, 2853, 1729, 1661, 1600, 1464, 1261,
1092, 870, 802 cm−1.
General Protocol for the Modification of Free Amine. To a
solution of substrate 11 (1.0 equiv) in dry dichloromethane was added
triethyl amine (3.0 equiv) and the corresponding sulfonyl chloride or
acetyl chloride (1.2 equiv) dropwise at 0 °C. The resulting mixture was
stirred at this temperature for 15 min. The reaction was quenched by
aqueous sodium bicarbonate and extracted with dichloromethane
three times. The combined extracts were washed with water and then
brine, dried over anhydrous Na2SO4, filtered, and concentrated in
vacuo to give a crude product, which was purified by column
chromatography on silica gel to afford the product 12. N-[2-(6-Bromo-
4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethyl]-2,2,2-
trifluoroacetamide (12a): TLC (hexanes:ethyl acetate, 3:1 v/v) Rf =
0.40; yellow oil, 82%; 1H NMR (500 MHz, CDCl3) δ 7.20 (dd, J = 8.2,
2.0 Hz, 1H), 7.14 (d, J = 2.0 Hz, 1H), 6.72 (brs, 1H), 6.60 (d, J = 8.2
Hz, 1H), 5.03 (s, 1H), 4.83 (s, 1H), 3.69 (t, J = 5.2 Hz, 1H), 3.46−
3.34 (m, 2H), 2.27−2.21 (m, 1H), 2.19−2.14 (m, 1H), 2.13−2.00 (m,
2H), 1.90−1.84 (m, 1H), 1.72−1.60 (m, 2H), 1.53−1.47 (m, 1H); 13C
NMR (75 MHz, CDCl3) δ 156.8, 148.3, 135.5, 130.9, 127.0, 112.4,
112.1, 65.4, 52.3, 36.9, 35.4, 32.5, 29.0, 21.6; HRMS (ESI) m/z calcd
for C17H19BrF3N2O [M + H]+ 403.0627, found 403.0622; IR (thin
film) 3322, 2957, 2928, 2861, 1663, 1599, 1530, 1463, 1378, 1008, 823
cm−1.
General Protocol for Gold(I)-Catalyzed Tandem Cyclization.
To a suspension of Ph3PAuNTf2 (as the 2:1 toluene adduct) (0.05
equiv) in anhydrous toluene was added a solution of indole 4 (1.0
equiv) in anhydrous toluene. The suspension was heated to 50 °C
until TLC showed that there was no starting material left (1−12 h)
under argon atmosphere. The reaction mixture was then filtered
through a short pad of silica gel. The filtrate was concentrated in vacuo
and the residue was purified by column chromatography on silica gel
to afford tetracyclic indoline product 5. 4-Chloro-16-(4-chlorobenze-
nesulfonyl)-13-methylidene-8,16-diazatetracyclo[7.4.3.01,9.02,7]-
hexadeca-2,4,6-triene (5a): TLC (hexanes:ethyl acetate, 3:1 v/v) Rf =
0.60; light yellow oil, 82%; 1H NMR (500 MHz, CDCl3) δ 7.61 (d, J =
8.8 Hz, 2H), 7.38 (d, J = 8.8 Hz, 2H), 7.05−7.03 (m, 2H), 6.51 (d, J =
8.1 Hz, 1H), 5.19 (brs, 1H), 4.92 (s, 1H), 4.77 (s, 1H), 3.48 (td, J =
8.7, 1.7 Hz, 1H), 3.03−2.98 (m, 1H), 2.72 (dt, J = 14.2, 3.8 Hz, 1H),
2.37 (ddd, J = 12.7, 10.5, 8.4 Hz, 1H), 2.24−2.12 (m, 3H), 1.93−1.86
(m, 1H), 1.75 (dt, J = 13.7, 4.5 Hz, 1H), 1.63−1.55 (m, 1H); 13C
NMR (75 MHz, CDCl3) δ 147.2, 146.4, 138.9, 138.4, 133.0, 129.2,
128.4, 128.3, 124.6, 123.8, 112.8, 111.0, 93.5, 61.1, 47.4, 33.8, 32.0,
30.3, 22.8; HRMS (ESI) m/z calcd for C21H21Cl2N2O2S [M + H]+
435.0695, found 435.0691; IR (thin film) 3054, 2986, 2926, 2850,
1478, 1423, 1335, 1265, 1156, 1090, 1001, 740 cm−1.
General Protocol for the Ring-Opening Reduction. To a
solution of the tetracyclic indoline 5 (1.0 equiv) in anhydrous
methanol was added acetic acid (2.0 equiv) and sodium cyanobor-
ohydride (4.0 equiv) at 0 °C. The resulting mixture was stirred at 23
°C for 0.5 h. The solvent was removed in vacuo to give a residue,
which was dissolved in ethyl acetate, and the organic layers were
washed with a saturated aqueous solution of sodium bicarbonate. The
combined organic layers were dried over anhydrous Na2SO4, filtered,
and concentrated in vacuo to give a crude product, which was purified
by column chromatography on silica gel to afford the product 6. 4-
Chloro-N-[2-(6-chloro-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]benzene-1-sulfonamide (6a): TLC (hexanes:ethyl
acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 92%; 1H NMR (500 MHz,
CDCl3) δ 7.77 (d, J = 8.6 Hz, 2H), 7.49 (d, J = 8.6 Hz, 2H), 7.01 (dd,
J = 8.3, 2.2 Hz, 1H), 6.87 (s, 1H), 6.58 (d, J = 8.3 Hz, 1H), 5.13 (d, J =
5.9 Hz, 1H), 4.94 (s, 1H), 4.67 (s, 1H), 3.63 (t, J = 4.9 Hz, 1H), 3.00−
2.89 (m, 1H), 2.20−2.11 (m, 2H), 2.07−2.01 (m, 1H), 1.98−1.93 (m,
1H), 1.81−1.76 (m, 1H), 1.70−1.57 (m, 2H), 1.52−1.46 (m, 1H); 13C
NMR (75 MHz, CDCl3) δ 148.6, 148.2, 139.2, 138.4, 135.1, 129.4,
128.5, 127.8, 124.2, 123.8, 112.1, 111.4, 77.5, 77.0, 76.6, 65.4, 52.3,
40.2, 36.1, 32.4, 28.6, 21.7; HRMS (ESI) m/z calcd for
C21H23Cl2N2O2S [M + H]+ 437.0852, found 437.0857; IR (thin
film) 2264, 3285, 2934, 2858, 1637, 1604, 1587, 1477, 1428, 1328,
1160, 1093, 1014,905, 827, 617 cm−1.
General Protocol for the Modification of 1’s Indoline Amine.
To a solution of substrate 1 (1.0 equiv) in dry acetonitrile was added
potassium carbonate (3.0 equiv) and the corresponding iodomethane
or sulfonyl chloride or acetyl chloride (1.2 equiv) dropwise at 0 °C.
The resulting mixture was stirred at this temperature for 15 min. The
reaction was quenched by aqueous sodium bicarbonate and extracted
with dichloromethane three times. The combined extracts were
washed with water and then brine, dried over anhydrous Na2SO4,
filtered, and concentrated in vacuo to give a crude product, which was
purified by column chromatography on silica gel to afford the products
1a−c. N-{2-[6-Bromo-9-(4-chlorobenzenesulfonyl)-4-methylidene-
2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl]ethyl}-4-chlorobenzene-1-
sulfonamide (1b): TLC (hexanes:ethyl acetate, 2:1 v/v) Rf = 0.60;
1
light yellow oil, 72%; H NMR (500 MHz, CDCl3) δ 7.82 (d, J = 8.6
Hz, 2H), 7.74 (d, J = 8.6 Hz, 2H), 7.57−7.45 (m, 5H), 7.38 (dd, J =
8.6, 2.1 Hz, 1H), 6.99 (d, J = 2.1 Hz, 1H), 5.13 (d, J = 2.0 Hz, 1H),
4.86 (d, J = 2.0 Hz, 1H), 4.11 (dd, J = 7.9, 5.7 Hz, 1H), 3.98 (d, J = 5.1
Hz, 1H), 2.83−2.77 (m, 1H), 2.74−2.64 (m, 1H), 2.29−2.24 (m, 1H),
2.05−1.98 (m, 1H), 1.96−1.89 (m, 1H), 1.69−1.61 (m, 2H), 1.21−
1.15 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 144.8, 140.1, 139.4,
139.2, 138.4, 138.2, 137.2, 131.9, 129.8, 129.5, 128.4, 128.3, 127.0,
117.0, 116.8, 113.7, 68.3, 52.1, 39.0, 38.3, 31.6, 29.7, 19.9; HRMS
(ESI) m/z calcd for C27H25BrCl2KN2O4S2 [M + K]+ 692.9448, found
692.9451; IR (thin film) 2292, 2920, 2850, 1638, 1475, 1360, 1338,
1166, 1093, 826, 756 cm−1.
General Protocol for the Removal of a Cbz Group. To a
solution of substrate 10 (1.0 equiv) in dry dichloromethane was added
boron trifluoride diethyl etherate (5.0 equiv) and dimethyl sulfide
(10.0 equiv) dropwise at 23 °C. The resulting mixture was stirred at
this temperature for 2 h. After that, TLC showed that there was no
starting material left; the mixture was poured into water and 10%
aqueous ammonium hydroxide and extracted with chloroform three
times. The combined extracts were washed with water and then brine,
dried over anhydrous Na2SO4, filtered, and concentrated in vacuo to
give a crude product, which was purified by column chromatography
on silica gel to afford the product 11. 2-(6-Bromo-4-methylidene-
2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethan-1-amine (11a): TLC
(chloroform:methanol, 10:1 v/v): Rf = 0.10; yellow oil, 72%; 1H NMR
(500 MHz, CDCl3) δ 7.20 (d, J = 2.0 Hz, 1H), 7.15 (dd, J = 8.3, 2.1
Hz, 1H), 6.55 (d, J = 8.2 Hz, 1H), 4.88 (s, 1H), 4.60 (d, J = 1.5 Hz,
1H), 3.72 (d, J = 3.2 Hz, 1H), 3.64 (s, 1H), 2.86−2.80 (m, 1H), 2.73−
2.67 (m, 1H), 2.25−2.16 (m, 3H), 2.01−1.98 (m, 1H), 1.94−1.88 (m,
1H), 1.85−1.79 (m, 1H), 1.77−1.67 (m, 2H), 1.63−1.58 (m, 1H); 13C
NMR (75 MHz, CDCl3) δ 149.8, 149.0, 137.1, 130.2, 127.4, 111.6,
Protocol for the Synthesis of 1d. To a solution of sodium
hydride (0.7 mg, 0.02 mmol) in dry N,N-dimethylformamide was
added 1 (6.0 mg, 0.012 mmol) dropwise at 0 °C. After 15 min,
iodomethane (3.9 μL, 0.06 mmol) was added dropwise at 0 °C. The
resulting mixture was stirred at this temperature for 15 min and then
warmed up to 60 °C for 30 min. The reaction was quenched by
aqueous ammonium chloride and extracted with ethyl acetate three
times. The combined extracts were washed with water and then brine,
dried over anhydrous Na2SO4, filtered, and concentrated in vacuo to
give a crude product, which was purified by column chromatography
on silica gel to afford the product 1d. N-[2-(6-Bromo-4-methylidene-
2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethyl]-4-chloro-N-methyl-
benzene-1-sulfonamide (1d): TLC (hexanes:ethyl acetate, 2:1 v/v) Rf
1
= 0.45; light yellow oil, 5.5 mg, 89%; H NMR (500 MHz, CDCl3) δ
7.70 (d, J = 8.5 Hz, 2H), 7.50 (d, J = 8.5 Hz, 2H), 7.16 (dd, J = 8.2, 2.0
Hz, 1H), 7.09 (s, 1H), 6.55 (d, J = 8.2 Hz, 1H), 4.95 (s, 1H), 4.66 (s,
1H), 3.70 (t, J = 4.5 Hz, 1H), 3.18 (ddd, J = 13.6, 11.2, 5.4 Hz, 1H),
2.97 (ddd, J = 13.6, 11.0, 5.1 Hz, 1H), 2.78 (s, 3H), 2.14−2.00 (m,
3H), 1.87−1.79 (m, 1H), 1.73−1.66 (m, 2H); 13C NMR (75 MHz,
3809
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CDCl3) δ 149.4, 139.1, 135.9, 130.6, 129.5, 129.4, 129.1, 128.7, 126.7,
111.8, 110.0, 109.6, 61.7, 51.4, 47.4, 37.9, 35.2, 33.1, 32.8, 21.8; HRMS
(ESI) m/z calcd for C22H24BrClKN2O2S [M + K]+ 533.0062, found
533.0068; IR (thin film) 3371, 2925, 2853, 2359, 1636, 1474, 1344,
1260, 1160, 1104, 1014, 804 cm−1.
1H NMR (500 MHz, CDCl3) δ 7.84 (d, J = 8.6 Hz, 2H), 7.51 (d, J =
8.6 Hz, 2H), 7.41 (s, 5H), 7.14 (dd, J = 8.2, 2.0 Hz, 1H), 6.88 (d, J =
2.0 Hz, 1H), 6.51 (d, J = 8.2 Hz, 1H), 4.91 (s, 1H), 4.60 (s, 1H),
3.97−3.86 (m, 1H), 3.76−3.66 (m, 1H), 3.62 (t, J = 4.6 Hz, 1H),
2.21−2.09 (m, 4H), 2.07 (t, J = 4.6 Hz, 1H), 1.82−1.76 (m, 1H),
1.70−1.64 (m, 4H); 13C NMR (75 MHz, CDCl3) δ 170.2, 144.4,
140.8, 139.7, 138.4, 136.7, 133.0, 131.2, 129.6, 129.5, 129.5, 129.1,
129.0, 128.6, 126.5, 119.1, 117.1, 114.0, 67.5, 51.4, 44.3, 36.6, 32.8,
21.6; HRMS (ESI) m/z calcd for C28H25BrCl2KN2O3S [M + K]+
656.9778, found 656.9777; IR (thin film) 3374, 2921, 2851, 1637,
1465, 1376, 1261, 1165, 1091, 1013, 827, 758 cm−1.
General Protocol for the Modification of 1’s Side Chain
Amine. To a solution of substrate 1 (1.0 equiv) in dry dichloro-
methane was added triethylamine (3.0 equiv) and the corresponding
sulfonyl chloride or acetyl chloride (1.2 equiv) dropwise at 0 °C. The
resulting mixture was stirred at this temperature for 15 min. The
reaction was quenched by aqueous sodium bicarbonate and extracted
with dichloromethane three times. The combined extracts were
washed with water and then brine, dried over anhydrous Na2SO4,
filtered, and concentrated in vacuo to give a crude product, which was
purified by column chromatography on silica gel to afford the product
1e or 1f. 2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)-N-(4-chlorobenzenesulfonyl)-S-(4-chlorophenyl)ethane-
1-sulfonamido (1e): TLC (hexanes:ethyl acetate, 2:1 v/v) Rf = 0.75;
colorless oil, 52%; 1H NMR (500 MHz, CDCl3) δ 7.94 (d, J = 8.7 Hz,
4H), 7.55 (d, J = 8.7 Hz, 4H), 7.25−7.12 (m, 2H), 6.57 (d, J = 8.2 Hz,
1H), 4.97 (s, 1H), 4.71 (s, 1H), 3.83 (ddd, J = 15.4, 12.5, 5.3 Hz, 1H),
3.68 (t, J = 4.4 Hz, 1H), 3.51 (ddd, J = 15.2, 12.3, 4.6 Hz, 1H), 2.33−
2.12 (m, 4H), 1.89−1.79 (m, 1H), 1.75−1.67 (m, 3H); 13C NMR (75
MHz, CDCl3) δ 148.9, 148.1, 141.0, 138.0, 135.0, 130.8, 129.8, 127.7,
124.6, 112.3, 111.9, 110.2, 65.1, 52.1, 39.4, 35.5, 32.3, 20.0; HRMS
(ESI) m/z calcd for C27H26BrCl2N2O4S2 [M + H]+ 654.9889, found
654.9871; IR (thin film) 2922, 2851, 1736, 1655, 1476, 1377, 1167,
1080, 826, 756, 620 cm−1.
Protocol for the Reduction of 12o. To a solution of substrate
12n (4.0 mg, 0.008 mmol) in methanol was added a solution of
ammonium chloride (8.7 mg, 0.162 mmol) in water and zinc dust (5.3
mg, 0.08 mmol) at room temperature. The resulting mixture was
stirred for 6 h and then filtered. The filtrate was removed under reduce
pressure and the residue was diluted with 2 N sodium hydroxide and
extracted with ethyl acetate three times. The combined extracts were
washed with water and then brine, dried over anhydrous Na2SO4,
filtered, and concentrated in vacuo to give a crude product, which was
purified by column chromatography on silica gel to afford the product
12o. 2-Amino-N-[2-(6-bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (12o): TLC (hexane-
s:ethyl acetate, 1:1 v/v) Rf = 0.30; colorless oil, 2.9 mg, 79%; 1H NMR
(500 MHz, CDCl3) δ 7.70 (d, J = 7.9 Hz, 1H), 7.35 (t, J = 7.7 Hz,
1H), 7.19−7.12 (m, 1H), 7.01 (s, 1H), 6.84 (t, J = 7.6 Hz, 1H), 6.79
(d, J = 8.2 Hz, 1H), 6.52 (d, J = 8.3 Hz, 1H), 4.97 (d, J = 6.8 Hz, 1H),
4.89 (s, 1H), 4.58 (s, 1H), 3.60 (s, 1H), 2.98−2.88 (m, 2H), 2.13 (q, J
= 4.7 Hz, 2H), 1.98 (ddd, J = 15.2, 9.2, 6.2 Hz, 1H), 1.89 (ddd, J =
14.5, 9.0, 5.9 Hz, 1H), 1.77−1.73 (m, 1H), 1.69−1.62 (m, 2H), 1.52−
1.47 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.7, 147.4, 138.0,
136.0, 135.8, 134.3, 133.1, 130.6, 129.5, 126.7, 121.7, 117.5, 112.0,
111.7, 110.5, 65.2, 52.2, 40.2, 35.4, 32.2, 28.4, 21.6; HRMS (ESI) m/z
calcd for C21H25BrN3O2S [M + H]+ 462.0845, found 462.0835; IR
(thin film) 3370, 2924, 2853, 1712, 1599, 1481, 1454, 1318, 1260, 901,
809, 754 cm−1.
4-Chloro-N-{2-[5-methyl-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-
benzene-1-sulfonamide (4b). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
1
= 0.20; light yellow oil, 41%; H NMR (500 MHz, CDCl3) δ 7.88 (s,
1H), 7.63 (d, J = 8.8 Hz, 2H), 7.37 (d, J = 8.7 Hz, 2H), 7.18 (d, J = 8.2
Hz, 1H), 7.09 (s, 1H), 6.98 (dd, J = 8.3, 1.7 Hz, 1H), 4.50 (t, J = 6.1
Hz, 1H), 3.25 (q, J = 6.5 Hz, 2H), 2.92 (t, J = 6.7 Hz, 2H), 2.83 (t, J =
7.4 Hz, 2H), 2.42 (s, 3H), 2.20 (td, J = 6.8, 2.7 Hz, 2H), 2.08 (t, J =
2.5 Hz, 1H), 1.85−1.80 (m, 2H); 13C NMR (75 MHz, CDCl3) δ138.9,
138.2, 135.9, 133.7, 129.2, 128.9, 128.4, 128.1, 123.2, 117.5, 110.3,
106.7, 83.7, 69.7, 43.2, 28.3, 24.5, 24.5, 21.5, 17.7; HRMS (ESI) m/z
calcd for C22H24ClN2O2S [M + H]+ 415.1242, found 415.1249; IR
(thin film) 3394, 3298, 2937, 2860, 1587, 1477, 1456, 1326, 1161,
1093, 828, 754, 619 cm−1.
4-Chloro-N-{2-[5-methoxy-2-(pent-4-yn-1-yl)-1H-indol-3-yl]-
ethyl}benzene-1-sulfonamide (4c). TLC (hexanes:ethyl acetate, 3:1
1
v/v) Rf = 0.25; colorless oil, 42%; H NMR (500 MHz, CDCl3) δ
7.97−7.90 (brm, 1H), 7.64 (d, J = 8.7 Hz, 2H), 7.37 (d, J = 8.4 Hz,
2H), 7.17 (d, J = 8.5 Hz, 1H), 6.86−6.76 (m, 2H), 4.71−4.59 (m,
1H), 3.82 (s, 3H), 3.22 (q, J = 6.6 Hz, 2H), 2.92 (t, J = 6.8 Hz, 2H),
2.81 (t, J = 7.5 Hz, 2H), 2.19 (td, J = 6.9, 2.8 Hz, 2H), 2.07 (s, 1H),
1.81 (p, J = 7.2 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 154.1, 138.9,
138.2, 136.6, 130.5, 129.2, 128.4, 128.4, 111.3, 111.2, 107.1, 100.3,
83.7, 69.7, 55.9, 43.2, 28.3, 24.6, 24.6, 17.7; HRMS (ESI) m/z calcd for
C22H24ClN2O2S [M + H]+ 431.1191, found 431.1194; IR (thin film)
3395, 3296, 2940, 2833, 1683, 1500, 1455, 1434, 1396, 1327, 1217,
1159, 1095, 1030, 1014, 829, 737 cm−1.
4-Chloro-N-{2-[5-fluoro-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-
benzene-1-sulfonamide (4d). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
1
= 0.25; light yellow oil, 22%; H NMR (500 MHz, CDCl3) δ 8.01 (s,
1H), 7.66 (d, J = 8.2 Hz, 2H), 7.39 (d, J = 8.2 Hz, 2H), 7.19 (dd, J =
8.7, 4.3 Hz, 1H), 6.94 (dd, J = 9.5, 2.5 Hz, 1H), 6.88 (td, J = 9.0, 2.5
Hz, 1H), 4.56 (t, J = 6.3 Hz, 1H), 3.23 (q, J = 6.6 Hz, 2H), 2.91−2.83
(m, 4H), 2.21 (dt, J = 6.9, 3.8 Hz, 2H), 2.08 (d, J = 2.6 Hz, 1H), 1.84
(t, J = 7.2 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 159.3, 156.2, 139.1,
138.2, 137.7, 131.8, 129.3, 128.3, 113.1, 111.3, 111.1, 109.9, 109.6,
107.5, 107.5, 103.0, 102.7, 83.5, 69.8, 43.1, 28.2, 24.6, 24.6, 17.7;
HRMS (ESI) m/z calcd for C21H21ClFN2O2S [M + H]+ 419.0991,
found 419.0995; IR (thin film) 3381, 3300, 2922, 2851, 1631, 1586,
1511, 1486, 1455, 1326, 1160, 1094, 827, 616 cm−1.
4-Chloro-N-{2-[2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}benzene-1-
sulfonamide (4e). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.25;
colorless oil, 35%; 1H NMR (500 MHz, CDCl3) δ 7.98 (brs, 1H), 7.64
(d, J = 8.5 Hz, 2H), 7.38 (d, J = 8.5 Hz, 2H), 7.34 (d, J = 7.9 Hz, 1H),
7.30 (d, J = 8.1 Hz, 1H), 7.16 (t, J = 7.6 Hz, 1H), 7.06 (t, J = 7.5 Hz,
1H), 4.50 (t, J = 6.2 Hz, 1H), 3.26 (q, J = 6.6 Hz, 2H), 2.95 (t, J = 6.8
Hz, 2H), 2.86 (t, J = 7.4 Hz, 2H), 2.22 (td, J = 6.9, 2.8 Hz, 2H), 2.08
(s, 1H), 1.84 (p, J = 7.1 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ
138.9, 138.2, 135.7, 135.4, 129.2, 128.4, 127.9, 121.7, 119.6, 117.8,
110.6, 107.2, 83.6, 69.7, 43.3, 28.3, 24.6, 24.5, 17.7; HRMS (ESI) m/z
calcd for C21H22ClN2O2S [M + H]+ 401.1085, found 401.1073; IR
(thin film) 3395, 3299, 2924, 2853, 1678, 1586, 1477, 1396, 1327,
1160, 1094, 893, 828 cm−1.
N-{2-[6-Bromo-9-(4-chlorobenzoyl)-4-methylidene-2,3,4,4a,9,9a-
hexahydro-1H-carbazol-4a-yl]ethyl}-4-chlorobenzene-1-sulfona-
mide (1c). TLC (hexanes:ethyl acetate, 2:1 v/v) Rf = 0.60; light yellow
oil, 92%; 1H NMR (500 MHz, CDCl3) δ 7.74 (d, J = 8.6 Hz, 2H), 7.49
(d, J = 8.6 Hz, 2H), 7.44 (q, J = 8.2 Hz, 4H), 7.10 (d, J = 2.0 Hz, 1H),
5.22 (s, 1H), 5.01 (s, 1H), 4.77−4.68 (m, 1H), 4.30 (brs, 1H), 3.11−
3.04 (m, 1H), 2.99−2.87 (m, 1H), 2.29 (d, J = 14.5 Hz, H), 2.04 (d, J
= 10.0 Hz, 1H), 1.97−1.88 (m, 2H), 1.54 (dt, J = 13.5, 4.3 Hz, 1H);
13C NMR (75 MHz, CDCl3) δ 173.0, 144.9, 139.6, 139.4, 138.2, 137.0,
134.1, 131.2, 129.5, 129.2, 128.7, 128.5, 126.5, 117.2, 113.8, 67.4, 51.4,
39.7, 37.7, 32.7, 21.4; HRMS (ESI) m/z calcd for
C28H25BrCl2KN2O3S [M + K]+ 656.9778, found 656.9780; IR (thin
film) 2916, 2849, 1631, 1587, 1469, 1422, 1380, 1331, 1163, 1089,
1014, 829, 740 cm−1.
4-Chloro-N-{2-[2-(pent-4-yn-1-yl)-1H-benzo[g]indol-3-yl]ethyl}-
benzene-1-sulfonamide (4f). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
1
= 0.22; colorless oil, 31%; H NMR (500 MHz, CDCl3) δ 8.71 (brs,
1H), 7.97 (d, J = 8.2 Hz, 1H), 7.93 (d, J = 8.1 Hz, 1H), 7.65−7.59 (m,
2H), 7.54 (ddd, J = 8.2, 6.8, 1.3 Hz, 1H), 7.48−7.41 (m, 3H), 7.31 (d,
J = 8.6 Hz, 2H), 4.44 (t, J = 6.1 Hz, 1H), 3.29 (q, J = 6.5 Hz, 2H), 3.02
(t, J = 6.7 Hz, 2H), 2.95 (t, J = 7.4 Hz, 2H), 2.26 (td, J = 6.8, 2.7 Hz,
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-chloro-N-(4-chlorobenzenesulfonyl)benzamide
(1f). TLC (hexanes:ethyl acetate, 2:1 v/v) Rf = 0.70; colorless oil, 92%;
3810
dx.doi.org/10.1021/jm500146g | J. Med. Chem. 2014, 57, 3803−3817

Journal of Medicinal Chemistry
Article
2H), 2.14 (t, J = 2.6 Hz, 1H), 1.90 (p, J = 7.0 Hz, 2H); 13C NMR (75
MHz, CDCl3) δ 138.2, 133.7, 130.1, 129.7, 129.2, 129.0, 128.3, 125.6,
123.8, 123.5, 121.2, 120.5, 119.1, 117.9, 109.1, 83.7, 69.9, 43.6, 31.9,
31.6, 28.6, 24.6, 24.5, 22.7, 17.7; HRMS (ESI) m/z calcd for
C25H24ClN2O2S [M + H]+ 451.1242, found 451.1246; IR (thin film)
3424, 2952, 2843, 1646, 1454, 1405, 1111, 1032, 1016, 623 cm−1.
N-{2-[7-Bromo-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-4-chloro-
benzene-1-sulfonamide (4g). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
= 0.25; light yellow oil, 22%; 1H NMR (500 MHz, CDCl3) δ 8.56 (brs,
1H), 7.83 (d, J = 8.3 Hz, 2H), 7.55−7.43 (m, 3H), 7.30 (d, J = 7.6 Hz,
1H), 6.98 (t, J = 7.7 Hz, 1H), 4.99 (t, J = 6.5 Hz, 1H), 3.01 (q, J = 6.3
Hz, 2H), 2.90 (t, J = 7.1 Hz, 4H), 2.47 (td, J = 7.5, 2.6 Hz, 2H), 1.96
(s, 1H), 1.88 (p, J = 6.8 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ
139.4, 138.1, 135.4, 134.1, 129.6, 129.3, 129.2, 128.5, 123.7, 120.5,
117.3, 111.8, 104.3, 84.3, 69.0, 42.2, 30.3, 23.8, 22.4, 20.0; HRMS
(ESI) m/z calcd for C21H21BrClN2O2S [M + H]+ 479.0190, found
479.0186; IR (thin film) 3299, 2917, 2849, 1710, 1585, 1451, 1326,
1160, 1095, 1014, 828 cm−1.
N-{2-[6-Bromo-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-4-chloro-
benzene-1-sulfonamide (4h). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
= 0.26; light yellow oil, 17%; 1H NMR (500 MHz, CDCl3) δ 7.99 (brs,
1H), 7.65 (d, J = 8.4 Hz, 2H), 7.44 (s, 1H), 7.39 (d, J = 8.3 Hz, 2H),
7.19 (d, J = 8.4 Hz, 1H), 7.17−7.08 (m, 1H), 4.47 (t, J = 6.3 Hz, 1H),
3.23 (q, J = 6.6 Hz, 2H), 2.92 (t, J = 6.8 Hz, 2H), 2.84 (t, J = 7.4 Hz,
2H), 2.21 (dt, J = 6.9, 3.3 Hz, 2H), 2.08 (s, 1H), 1.83 (p, J = 7.1 Hz,
2H); 13C NMR (75 MHz, CDCl3) δ 139.1, 138.2, 136.4, 136.1, 129.2,
128.3, 126.8, 122.8, 119.0, 115.1, 113.6, 107.6, 83.5, 69.9, 43.2, 28.1,
24.6, 24.4, 17.7; HRMS (ESI) m/z calcd for C21H21BrClN2O2S [M +
H]+ 479.0190, found 479.0180; IR (thin film) 3356, 3299, 2924, 2851,
2359, 2342, 1716, 1587, 1506, 1463, 1326, 1159, 1094, 1014, 828
cm−1.
(d, J = 8.6 Hz, 1H), 5.12 (s, 2H), 4.82 (t, J = 6.1 Hz, 1H), 3.45 (q, J =
6.7 Hz, 2H), 2.90 (t, J = 6.9 Hz, 2H), 2.85 (t, J = 7.4 Hz, 2H), 2.21 (td,
J = 6.9, 2.7 Hz, 2H), 2.07 (t, J = 2.5 Hz, 1H), 1.84 (h, J = 6.1, 5.0 Hz,
2H); 13C NMR (75 MHz, CDCl3) δ 156.3, 136.8, 136.5, 134.0, 130.2,
128.6, 128.5, 128.3, 128.1, 128.1, 124.2, 120.7, 112.7, 111.9, 108.5,
83.6, 69.7, 66.7, 41.5, 28.2, 24.6, 24.5, 17.7; HRMS (ESI) m/z calcd for
C23H24BrN2O2 [M + H]+ 439.1016, found 439.1016; IR (thin film)
3295, 2920, 2850, 1698, 1518, 1454, 1251, 1135, 1075, 797, 748 cm−1.
Benzyl {2-[5-Bromo-7-fluoro-2-(pent-4-yn-1-yl)-1H-indol-3-yl]-
ethyl}carbamate (8b). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf =
1
0.20; light yellow oil, 31%; H NMR (500 MHz, CDCl3) δ 9.82 (brs,
1H), 7.49−7.32 (m, 6H), 7.01 (dd, J = 10.1, 1.6 Hz, 1H), 5.19 (s, 2H),
4.96 (brs, 1H), 3.33 (q, J = 6.3 Hz, 2H), 2.90 (t, J = 7.5 Hz, 2H), 2.81
(t, J = 6.7 Hz, 2H), 2.47 (td, J = 7.5, 2.7 Hz, 2H), 1.98 (s, 1H), 1.83 (p,
J = 6.6 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 157.7, 137.5, 136.2,
132.7, 132.7, 128.6, 128.3, 128.2, 122.3, 116.5, 110.5, 109.8, 109.6,
84.2, 69.0, 67.2, 39.5, 31.0, 23.6, 21.9, 20.1; HRMS (ESI) m/z calcd for
C23H23BrFN2O2 [M + H]+ 457.0921, found 457.0924; IR (thin film)
3298, 2923, 2851, 1701, 1638, 1523, 1477, 1454, 1308, 1255, 1217,
1131, 1005, 882, 826, 697 cm−1.
16-(4-Chlorobenzenesulfonyl)-4-methyl-13-methylidene-8,16-
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5b). TLC (hex-
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 90%; H NMR
(500 MHz, CDCl3) δ 7.59 (d, J = 8.7 Hz, 2H), 7.34 (d, J = 8.7 Hz,
2H), 6.92−6.84 (m, 2H), 6.48 (d, J = 7.8 Hz, 1H), 5.06 (brs, 1H), 4.89
(s, 1H), 4.78 (s, 1H), 3.48 (td, J = 8.6, 1.7 Hz, 1H), 2.95 (ddd, J =
10.3, 8.7, 6.8 Hz, 1H), 2.73 (dt, J = 14.1, 3.8 Hz, 1H), 2.37 (ddd, J =
12.5, 10.4, 8.3 Hz, 1H), 2.27 (s, 3H), 2.26−2.19 (m, 1H), 2.15 (ddd, J
= 14.2, 10.2, 5.2 Hz, 1H), 1.93 (ddd, J = 13.9, 12.5, 4.6 Hz, 1H), 1.77−
1.71 (m, 1H), 1.60 (tdd, J = 18.0, 9.9, 4.8 Hz, 1H); 13C NMR (75
MHz, CDCl3) δ 148.0, 145.4, 138.6, 138.5, 131.2, 129.0, 128.8, 128.5,
128.4, 125.0, 112.4, 110.1, 93.7, 61.0, 47.4, 34.2, 32.1, 30.5, 23.1, 21.0;
HRMS (ESI) m/z calcd for C22H24ClN2O2S [M + H]+ 415.1242,
found 415.1245; IR (thin film) 3391, 3088, 2941, 2865, 1639, 1585,
1493, 1332, 1155, 1089, 1002, 904, 813, 623 cm−1.
N-{2-[4-Bromo-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-4-chloro-
benzene-1-sulfonamide (4i). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf
1
= 0.24; colorless oil, 11%; H NMR (500 MHz, CDCl3) δ 8.07 (brs,
1H), 7.67 (d, J = 8.6 Hz, 2H), 7.37 (d, J = 8.6 Hz, 2H), 7.24 (d, J = 8.0
Hz, 1H), 7.21 (d, J = 7.5 Hz, 1H), 6.97 (t, J = 8.0 Hz, 1H), 4.53 (t, J =
6.1 Hz, 1H), 3.32 (q, J = 6.7 Hz, 2H), 3.15 (t, J = 7.0 Hz, 2H), 2.94−
2.87 (m, 2H), 2.32−2.20 (m, 2H), 2.12 (t, J = 2.6 Hz, 1H), 1.90−1.83
(m, 2H); 13C NMR (75 MHz, CDCl3) δ 138.8, 138.5, 137.4, 136.6,
129.6, 128.7, 125.8, 124.5, 124.2, 122.7, 122.4, 113.0, 110.0, 108.4,
83.2, 69.9, 45.1, 28.0, 24.6, 17.8; HRMS (ESI) m/z calcd for
C21H21BrClN2O2S [M + H]+ 479.0190, found 479.0197; IR (thin
film) 3304, 2919, 2850, 1718, 1654, 1458, 1276, 1106, 913, 750 cm−1.
4-Chloro-N-{2-[5-chloro-7-fluoro-2-(pent-4-yn-1-yl)-1H-indol-3-
yl]ethyl}benzene-1-sulfonamide (4j). TLC (hexanes:ethyl acetate, 3:1
16-(4-Chlorobenzenesulfonyl)-4-methoxy-13-methylidene-8,16-
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5c). TLC (hex-
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 92%; H NMR
(500 MHz, CDCl3) δ 7.58 (d, J = 8.6 Hz, 2H), 7.34 (d, J = 8.6 Hz,
2H), 6.70 (d, J = 2.5 Hz, 1H), 6.62 (dd, J = 8.4, 2.5 Hz, 1H), 6.48 (d, J
= 8.4 Hz, 1H), 4.95 (brs, 1H), 4.90 (s, 1H), 4.77 (s, 1H), 3.76 (s, 3H),
3.50 (td, J = 8.6, 1.5 Hz, 1H), 2.94 (ddt, J = 11.2, 6.8, 5.6 Hz, 1H),
2.73 (dtd, J = 14.1, 3.8, 1.2 Hz, 1H), 2.41−2.35 (m, 1H), 2.28−2.11
(m, 3H), 1.96−1.89 (m, 1H), 1.81−1.72 (m, 1H), 1.64−1.57 (m, 1H);
13C NMR (75 MHz, CDCl3) δ 153.5, 147.6, 141.5, 138.6, 138.4, 132.7,
129.4, 129.3, 129.0, 128.5, 128.4, 128.4, 112.7, 112.7, 111.7, 110.7,
94.1, 69.6, 61.2, 56.0, 47.4, 34.3, 31.9, 30.6, 23.2; HRMS (ESI) m/z
calcd for C22H24ClN2O2S [M + H]+ 431.1191, found 431.1195; IR
(thin film) 3386, 3300, 2942, 2866, 1708, 1586, 1491, 1333, 1158,
1003, 829 cm−1.
1
v/v) Rf = 0.20; light yellow oil, 20%; H NMR (500 MHz, CDCl3) δ
8.23 (brs, 1H), 7.68 (d, J = 8.7 Hz, 2H), 7.42 (d, J = 8.7 Hz, 2H), 7.05
(d, J = 1.8 Hz, 1H), 6.88 (dd, J = 10.4, 1.7 Hz, 1H), 4.54 (t, J = 6.2 Hz,
1H), 3.23 (q, J = 6.6 Hz, 2H), 2.90−2.87 (m, 4H), 2.26−2.20 (m,
2H), 2.09 (s, 1H), 1.91−1.82 (m, 2H); 13C NMR (75 MHz, CDCl3) δ
139.1, 138.2, 138.0, 129.3, 128.3, 124.8, 124.7, 113.4, 113.3, 108.2,
108.0, 107.8, 83.3, 70.0, 43.0, 28.0, 24.7, 24.5, 17.8; HRMS (ESI) m/z
calcd for C21H20Cl2FN2O2S [M + H]+ 453.0601, found 453.0616; IR
(thin film) 3445, 2962, 2081, 1652, 1456, 1261, 1096, 1033, 800 cm−1.
4-Chloro-N-{2-[5,7-dichloro-2-(pent-4-yn-1-yl)-1H-indol-3-yl]-
ethyl}benzene-1-sulfonamide (4k). TLC (hexanes:ethyl acetate, 3:1
16-(4-Chlorobenzenesulfonyl)-4-fluoro-13-methylidene-8,16-
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5d). TLC (hex-
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.50; light yellow oil, 78%; H NMR
(500 MHz, CDCl3) δ 7.60 (d, J = 8.6 Hz, 2H), 7.37 (d, J = 8.6 Hz,
2H), 6.83 (dd, J = 8.2, 2.6 Hz, 1H), 6.78 (td, J = 8.8, 2.6 Hz, 1H), 6.49
(dd, J = 8.5, 4.2 Hz, 1H), 5.08 (brs, 1H), 4.92 (s, 1H), 4.75 (s, 1H),
3.51 (td, J = 8.7, 1.6 Hz, 1H), 2.98 (ddd, J = 10.4, 8.8, 6.9 Hz, 1H),
2.73 (d, J = 14.1 Hz, 1H), 2.39 (ddd, J = 12.7, 10.4, 8.5 Hz, 1H), 2.28−
2.11 (m, 3H), 1.91 (td, J = 13.5, 4.6 Hz, 1H), 1.76 (dt, J = 13.4, 4.3
Hz, 1H), 1.60 (tdd, J = 13.3, 9.9, 6.4 Hz, 1H); 13C NMR (75 MHz,
CDCl3) δ 158.6, 155.4, 147.2, 143.7, 143.7, 138.8, 138.4, 134.2, 134.1,
132.9, 132.8, 132.0, 132.0, 129.3, 129.3, 129.2, 129.1, 128.4, 114.7,
114.4, 112.9, 112.1, 111.8, 110.7, 110.6, 94.1, 61.1, 61.1, 47.3, 34.1,
31.9, 30.5, 23.1; HRMS (ESI) m/z calcd for C21H21ClFN2O2S [M +
H]+ 419.0991, found 419.0995; IR (thin film) 3389, 3090, 2944, 2869,
1693, 1640, 1585, 1486, 1278, 1225, 1002, 884 cm−1.
1
v/v) Rf = 0.20; light yellow oil, 24%; H NMR (500 MHz, CDCl3) δ
8.16 (brs, 1H), 7.66 (d, J = 8.6 Hz, 2H), 7.41 (d, J = 8.6 Hz, 2H),
7.21−7.11 (m, 2H), 4.44 (t, J = 6.3 Hz, 1H), 3.23 (q, J = 6.6 Hz, 2H),
3.03−2.79 (m, 4H), 2.26 (td, J = 6.7, 2.7 Hz, 2H), 2.11 (s, 1H), 1.88
(p, J = 7.1 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 139.2, 138.2,
138.1, 131.2, 129.9, 129.3, 128.3, 125.3, 121.1, 116.5, 116.1, 108.5,
83.3, 70.0, 43.0, 28.0, 24.8, 24.5, 17.8; HRMS (ESI) m/z calcd for
C21H20Cl3N2O2S [M + H]+ 469.0306, found 469.0319; IR (thin film)
3353, 3301, 3088, 2928, 2854, 1713, 1574, 1476, 1328, 1161, 1095,
1014, 964, 912, 828, 753 cm−1.
Benzyl {2-[5-Bromo-2-(pent-4-yn-1-yl)-1H-indol-3-yl]ethyl}-
16-(4-Chlorobenzenesulfonyl)-13-methylidene-8,16-
carbamate (8a). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20;
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5e). TLC (hex-
1
1
light yellow oil, 30%; H NMR (500 MHz, CDCl3) δ 8.05 (brs, 1H),
anes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 82%; H NMR
7.65 (s, 1H), 7.40−7.31 (m, 5H), 7.23 (dd, J = 8.5, 1.9 Hz, 1H), 7.16
(500 MHz, CDCl3) δ 7.57 (d, J = 8.6 Hz, 2H), 7.34 (d, J = 8.6 Hz,
3811
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1
2H), 7.14−7.03 (m, 2H), 6.78 (t, J = 7.5 Hz, 1H), 6.57 (d, J = 7.8 Hz,
1H), 5.17 (brs, 1H), 4.90 (s, 1H), 4.76 (s, 1H), 3.50 (dd, J = 9.6, 8.0
Hz, 1H), 2.95 (ddd, J = 10.3, 8.7, 6.9 Hz, 1H), 2.79−2.70 (m, 1H),
2.43−2.37 (m, 1H), 2.30−2.21 (m, 2H), 2.17 (td, J = 14.1, 12.4, 5.0
Hz, 1H), 1.98−1.91 (m, 1H), 1.81−1.72 (m, 1H), 1.65−1.55 (m, 1H);
13C NMR (75 MHz, CDCl3) δ 147.8, 147.6, 138.7, 138.5, 131.0, 129.1,
128.4, 124.3, 119.2, 112.6, 110.3, 93.4, 60.9, 47.5, 34.2, 32.0, 30.5, 23.1;
HRMS (ESI) m/z calcd for C21H22ClN2O2S [M + H]+ 401.1085,
found 401.1095; IR (thin film) 3393, 3087, 2943, 2869, 1640, 1589,
1474, 1466, 1191, 893, 830 cm−1.
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 77%; H
NMR (500 MHz, CDCl3) δ 7.63 (d, J = 8.7 Hz, 2H), 7.40 (d, J = 8.7
Hz, 2H), 6.97−6.83 (m, 2H), 5.28 (brs, 1H), 4.94 (s, 1H), 4.73 (s,
1H), 3.55 (t, J = 8.6 Hz, 1H), 2.96−2.91 (m, 1H), 2.77 (dt, J = 14.4,
3.8 Hz, 1H), 2.44−2.38 (m, 1H), 2.27−2.09 (m, 3H), 1.94 (td, J =
13.5, 4.6 Hz, 1H), 1.79−1.75 (m, 1H); 13C NMR (75 MHz, CDCl3) δ
146.6, 139.0, 137.7, 129.2, 128.2, 123.5, 120.4, 120.4, 115.9, 115.6,
113.1, 93.5, 61.7, 47.4, 34.2, 31.9, 29.7, 22.8; HRMS (ESI) m/z calcd
for C21H20Cl2FN2O2S [M + H]+ 453.0601, found 453.0609; IR (thin
film) 3054, 2986, 2926, 2853, 1584, 1422, 1265, 1159, 1013, 975, 896,
740, 705 cm−1.
20-(4-Chlorobenzenesulfonyl)-17-methylidene-12,20-
diazapentacyclo[11.4.3.01,13.02,11.05,10]icosa-2,4,6,8,10-pentaene
(5f). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.55; colorless oil, 82%;
1H NMR (500 MHz, CDCl3) δ 7.80 (dd, J = 6.2, 3.3 Hz, 1H), 7.61
(4,6-Dichloro-16-(4-chlorobenzenesulfonyl)-13-methylidene-
8,16-diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5k). TLC
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 82%; H
NMR (500 MHz, CDCl3) δ 7.63 (d, J = 8.6 Hz, 2H), 7.39 (d, J = 8.7
Hz, 2H), 7.10 (d, J = 1.9 Hz, 1H), 6.93 (d, J = 1.9 Hz, 1H), 5.44 (brs,
1H), 4.94 (s, 1H), 4.74 (s, 1H), 3.53 (td, J = 8.6, 1.6 Hz, 1H), 2.90−
2.85 (m, 1H), 2.79 (dt, J = 14.3, 3.9 Hz, 1H), 2.45−2.38 (m, 1H),
2.24−2.16 (m, 3H), 1.96 (ddd, J = 14.1, 12.5, 4.7 Hz, 1H), 1.78−1.75
(m, 1H), 1.65−1.60 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 146.6,
143.9, 139.0, 137.7, 133.9, 129.2, 128.4, 127.8, 123.9, 123.2, 115.7,
113.1, 92.9, 62.2, 47.1, 34.1, 32.2, 30.2, 22.6; HRMS (ESI) m/z calcd
for C21H20Cl3N2O2S [M + H]+ 469.0306, found 469.0305; IR (thin
film) 3380, 2928, 2856, 2360,1700, 1636, 1583, 1464, 1336, 1156,
1092, 1010, 904, 631 cm−1.
(dd, J = 6.2, 3.3 Hz, 1H), 7.50−7.40 (m, 4H), 7.32 (d, J = 8.2 Hz, 1H),
7.26 (d, J = 6.0 Hz, 1H), 6.99 (d, J = 8.6 Hz, 2H), 5.63 (brs, 1H), 4.90
(s, 1H), 4.79 (s, 1H), 3.57 (td, J = 8.5, 1.5 Hz, 1H), 2.95−2.80 (m,
2H), 2.48 (ddd, J = 12.8, 10.7, 8.2 Hz, 1H), 2.37 (ddd, J = 12.9, 6.8,
1.5 Hz, 1H), 2.21 (t, J = 6.4 Hz, 2H), 2.10−1.98 (m, 1H), 1.88−1.77
(m, 1H), 1.73−1.63 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.6,
143.8, 138.4, 138.0, 134.0, 128.8, 128.5, 128.2, 128.2, 125.7, 125.1,
124.6, 122.1, 121.6, 120.6, 119.3, 112.4, 93.6, 61.9, 47.8, 34.4, 32.3,
30.3, 22.9; HRMS (ESI) m/z calcd for C25H24ClN2O2S [M + H]+
451.1242, found 451.1252; IR (thin film) 3370, 3302, 3054, 2924,
2853, 1713, 1633, 1587, 1476, 1391, 1327, 1265, 1160, 1093, 1014,
807 cm−1.
4-Chloro-N-[2-(6-methyl-4-methylidene-2,3,4,4a,9,9a-hexahy-
dro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (6b). TLC
6-Bromo-16-(4-chlorobenzenesulfonyl)-13-methylidene-8,16-
1
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5g). TLC (hex-
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.30; pink oil, 95%; H NMR
1
(500 MHz, CDCl3) δ 7.74 (d, J = 8.6 Hz, 2H), 7.46 (d, J = 8.6 Hz,
2H), 6.90−6.84 (m, 1H), 6.75−6.69 (m, 1H), 6.58 (d, J = 7.8 Hz,
1H), 5.29 (s, 1H), 4.93 (s, 1H), 4.70 (d, J = 1.4 Hz, 1H), 3.57 (t, J =
5.2 Hz, 1H), 3.03−2.98 (m, 1H), 2.90−2.78 (m, 1H), 2.24 (s, 3H),
2.17−2.10 (m, 2H), 2.07−1.92 (m, 2H), 1.82−1.76 (m, 1H), 1.68−
1.55 (m, 3H), 1.48−1.43 (m, 1H); 13C NMR (75 MHz, CDCl3) δ
149.3, 147.0, 138.9, 138.54, 133.3, 129.3, 128.9, 128.5, 128.4, 124.6,
111.7, 110.7, 65.3, 52.3, 40.4, 36.6, 32.7, 29.1, 21.90, 21.0; HRMS
(ESI) m/z calcd for C22H26ClN2O2S [M + H]+ 417.1398, found
417.1399; IR (thin film) 2927, 2856, 1491, 1476, 1395, 1329, 1276,
1161, 1014, 827, 752 cm−1.
anes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 72%; H NMR
(500 MHz, CDCl3) δ 7.62 (d, J = 8.6 Hz, 2H), 7.36 (d, J = 8.7 Hz,
2H), 7.23 (d, J = 8.0 Hz, 1H), 7.00 (d, J = 7.3 Hz, 1H), 6.65 (t, J = 7.7
Hz, 1H), 5.45 (s, 1H), 4.91 (s, 1H), 4.73 (s, 1H), 3.54 (td, J = 8.6, 1.6
Hz, 1H), 2.90−2.75 (m, 2H), 2.44 (ddd, J = 12.7, 10.6, 8.4 Hz, 1H),
2.20 (dtd, J = 19.1, 14.2, 7.6 Hz, 3H), 2.01 (td, J = 14.1, 13.6, 4.7 Hz,
1H), 1.78 (tt, J = 9.1, 4.6 Hz, 1H), 1.68−1.62 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 147.2, 146.5, 138.8, 137.7, 132.5, 131.0, 129.1, 128.5,
123.3, 120.3, 112.8, 103.9, 92.6, 62.3, 47.2, 34.5, 32.2, 30.4, 29.7, 22.8;
HRMS (ESI) m/z calcd for C21H21BrClN2O2S [M + H]+ 479.0190,
found 479.0204; IR (thin film) 3054, 2926, 2853, 1607, 1585, 1465,
1421, 1265, 1158, 1061, 1101, 896, 740 cm−1.
4-Chloro-N-[2-(6-methoxy-4-methylidene-2,3,4,4a,9,9a-hexahy-
dro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (6c). TLC
5-Bromo-16-(4-chlorobenzenesulfonyl)-13-methylidene-8,16-
1
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5h). TLC (hex-
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.40; pink oil, 97%; H NMR
1
(500 MHz, CDCl3) δ 7.75 (d, J = 8.8 Hz, 2H), 7.47 (d, J = 8.8 Hz,
1H), 6.81−6.75 (brm, 1H), 6.67 (dd, J = 8.5, 2.5 Hz, 1H), 6.56 (s,
1H), 5.56 (brs, 1H), 5.01 (s, 1H), 4.77 (s, 1H), 3.79 (s, 1H), 3.76 (s,
3H), 3.05−3.02 (m, 1H), 2.84−2.81 (m, 1H), 2.24−2.19 (m, 1H),
2.12−2.04 (m, 2H), 2.02−1.97 (m, 1H), 1.96−1.88 (m, 1H), 1.71−
1.65 (m, 1H), 1.64−1.56 (m, 1H), 1.50−1.44 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 138.9, 138.4, 129.5, 129.4, 129.3, 128.5, 112.9, 112.5,
110.7, 65.4, 55.9, 53.0, 40.3, 36.4, 32.7, 28.6, 22.0; HRMS (ESI) m/z
calcd for C22H26ClN2O3S [M + H]+ 433.1347, found 433.1336; IR
(thin film) 3286, 3087, 2927, 2854, 1930, 1637, 1587, 1488, 1435,
1329, 1278, 1263, 1219, 1161, 1094, 828 cm−1.
anes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 78%; H NMR
(500 MHz, CDCl3) δ 7.60 (d, J = 8.6 Hz, 2H), 7.40 (d, J = 8.6 Hz,
2H), 6.92 (d, J = 7.8 Hz, 1H), 6.88 (dd, J = 7.8, 1.7 Hz, 1H), 6.66 (d, J
= 1.6 Hz, 1H), 5.17 (brs, 1H), 4.90 (s, 1H), 4.72 (s, 1H), 3.50 (td, J =
8.6, 1.4 Hz, 1H), 3.04−2.96 (m, 1H), 2.76−2.67 (m, 1H), 2.40−2.34
(m, 1H), 2.27−2.19 (m, 2H), 2.18−2.10 (m, 1H), 1.92−1.86 (m, 1H),
1.78−1.71 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 149.0, 147.3,
139.0, 138.3, 134.3, 134.1, 132.0, 130.2, 129.3, 129.2, 129.2, 128.3,
125.5, 121.9, 121.9, 113.4, 112.8, 93.2, 60.6, 47.6, 34.1, 31.9, 29.7, 22.9;
HRMS (ESI) m/z calcd for C21H21BrClN2O2S [M + H]+ 479.0190,
found 479.0185; IR (thin film) 3391, 2917, 2849, 1602, 1585, 1478,
1436, 1392, 1333, 1154, 1104, 997, 752 cm−1.
4-Chloro-N-[2-(6-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (6d). TLC (hexa-
3-Bromo-16-(4-chlorobenzenesulfonyl)-13-methylidene-8,16-
1
diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5i). TLC (hex-
nes:ethyl acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 84%; H NMR
1
(500 MHz, CDCl3) δ 7.75 (d, J = 8.6 Hz, 2H), 7.48 (d, J = 8.6 Hz,
2H), 6.76 (td, J = 8.8, 2.6 Hz, 1H), 6.64 (dd, J = 8.3, 2.6 Hz, 1H), 6.58
(dd, J = 8.4, 4.3 Hz, 1H), 5.16 (t, J = 6.1 Hz, 1H), 4.94 (s, 1H), 4.67
(s, 1H), 3.63 (t, J = 5.0 Hz, 1H), 3.04−2.96 (m, 1H), 2.91−2.83 (m,
1H), 2.23−2.09 (m, 2H), 2.09−2.01 (m, 1H), 1.96 (ddd, J = 14.1, 8.4,
5.6 Hz, 1H), 1.80 (tt, J = 9.5, 4.9 Hz, 1H), 1.70−1.57 (m, 1H), 1.52−
1.45 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.8, 139.1, 138.4,
129.4, 128.5, 114.3, 114.0, 112.1, 111.6, 111.3, 111.1, 111.0, 65.7, 52.5,
40.2, 36.2, 32.5, 28.7, 21.8; HRMS (ESI) m/z calcd for
C21H23ClFN2O2S [M + H]+ 421.1147, found 421.1147; IR (thin
film) 3734, 2929, 1507, 1485, 1276, 1260, 1160, 1260, 1160, 1093,
1014, 828, 751 cm−1.
anes:ethyl acetate, 3:1 v/v) Rf = 0.20; colorless oil, 62%; H NMR
(500 MHz, CDCl3) δ 7.62 (d, J = 8.6 Hz, 2H), 7.38 (d, J = 8.6 Hz,
2H), 6.99−6.84 (m, 2H), 6.51 (dd, J = 7.6, 1.2 Hz, 1H), 5.24 (brs,
1H), 5.01 (s, 1H), 4.91 (s, 1H), 3.50 (t, J = 8.2 Hz, 1H), 3.16 (dd, J =
13.2, 6.3 Hz, 1H), 3.05−3.00 (m, 1H), 2.69 (ddd, J = 14.1, 4.7, 3.0 Hz,
1H), 2.32−2.26 (m, 1H), 2.16 (t, J = 6.6 Hz, 2H), 1.88 (td, J = 13.2,
5.2 Hz, 1H), 1.76−1.73 (m, 1H), 1.66−1.61 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 150.2, 146.5, 138.6, 130.8, 130.2, 129.1, 128.4, 124.0,
120.5, 114.4, 109.1, 93.4, 63.9, 47.6, 33.6, 32.8, 30.8, 29.4, 22.9; HRMS
(ESI) m/z calcd for C21H21BrClN2O2S [M + H]+ 479.0190, found
479.0188; IR (thin film) 3393, 2954, 2916, 2848, 1261, 1159, 1090,
912, 764 cm−1.
4-Chloro-16-(4-chlorobenzenesulfonyl)-6-fluoro-13-methylidene-
4-Chloro-N-[2-(4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]benzene-1-sulfonamide (6e). TLC (hexanes:ethyl
8,16-diazatetracyclo[7.4.3.01,9.02,7]hexadeca-2,4,6-triene (5j). TLC
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acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 95%; 1H NMR (500 MHz,
CDCl3) δ 7.73 (d, J = 8.6 Hz, 2H), 7.46 (d, J = 8.6 Hz, 2H), 7.06 (td, J
= 7.6, 1.3 Hz, 1H), 6.91 (dd, J = 7.3, 1.3 Hz, 1H), 6.75 (td, J = 7.4, 1.0
Hz, 1H), 6.66 (d, J = 7.8 Hz, 1H), 5.08 (t, J = 6.0 Hz, 1H), 4.92 (d, J =
1.6 Hz, 1H), 4.67 (d, J = 1.3 Hz, 1H), 3.60 (t, J = 4.9 Hz, 1H), 3.06−
2.96 (m, 1H), 2.93−2.87 (m, 1H), 2.15 (q, J = 5.5 Hz, 2H), 2.09−1.93
(m, 2H), 1.85−1.74 (m, 1H), 1.71−1.57 (m, 2H), 1.52−1.47 (m, 1H);
13C NMR (75 MHz, CDCl3) δ 149.5, 149.3, 139.0, 138.5, 133.0, 129.3,
128.5, 128.0, 124.1, 119.3, 111.8, 110.7, 65.2, 52.2, 40.4, 36.4, 32.5,
28.8, 21.8; HRMS (ESI) m/z calcd for C21H24ClN2O2S [M + H]+
403.1242, found 403.1241; IR (thin film) 3287, 2930, 2856, 1606,
1478, 1464, 1396, 1328, 1276, 1261, 1160, 1094, 1014, 902, 828, 751
cm−1.
(thin film) 2954, 2923, 2853, 1713, 1662, 1571, 1462, 1377, 1331,
1278, 1162, 1096, 1014, 906, 827 cm−1.
4-Chloro-N-[2-(6-chloro-8-fluoro-4-methylidene-2,3,4,4a,9,9a-
hexahydro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (6j).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.50; light yellow oil,
89%; 1H NMR (500 MHz, CDCl3) δ 7.77 (d, J = 8.6 Hz, 2H), 7.50 (d,
J = 8.5 Hz, 2H), 6.89 (dd, J = 9.9, 1.9 Hz, 1H), 6.72 (d, J = 1.9 Hz,
1H), 4.96 (s, 1H), 4.83 (t, J = 6.2 Hz, 1H), 4.67 (s, 1H), 3.70 (s, 1H),
3.01−2.89 (m, 2H), 2.21−2.12 (m, 2H), 2.10−2.04 (m, 1H), 2.01−
1.95 (m, 1H), 1.86−1.80 (m, 1H), 1.71−1.65 (m, 3H), 1.56−1.48 (m,
1H); 13C NMR (75 MHz, CDCl3) δ 148.1, 147.3, 139.2, 138.3, 137.7,
137.6, 135.8, 135.6, 129.5, 128.5, 120.0, 120.0, 115.5, 115.2, 112.4,
66.0, 52.9, 40.1, 36.0, 32.4, 31.9, 28.6, 21.6; HRMS (ESI) m/z calcd for
C21H22Cl2FN2O2S [M + H]+ 455.0758, found 455.0760; IR (thin film)
3054, 2986, 2926, 2853, 1584, 1422, 1265, 1159, 1013, 975, 896, 740
cm−1.
4-Chloro-N-(2-{7-methylidene-6bH,7H,8H,9H,10H,10aH,11H-
benzo[a]carbazol-6b-yl}ethyl)benzene-1-sulfonamide (6f). TLC
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.40; light yellow oil, 90%; H
4-Chloro-N-[2-(6,8-dichloro-4-methylidene-2,3,4,4a,9,9a-hexahy-
NMR (500 MHz, CDCl3) δ 7.81 (dt, J = 6.9, 3.5 Hz, 1H), 7.63 (dd, J
= 6.2, 3.3 Hz, 1H), 7.56 (d, J = 8.6 Hz, 1H), 7.46 (dp, J = 6.7, 3.5 Hz,
2H), 7.30 (d, J = 8.2 Hz, 1H), 7.25 (d, J = 8.5 Hz, 2H), 7.08 (d, J = 8.2
Hz, 1H), 5.39 (t, J = 6.3 Hz, 1H), 4.97 (s, 1H), 4.79 (s, 1H), 3.80 (t, J
= 5.0 Hz, 1H), 2.97 (dtd, J = 13.0, 7.3, 5.6 Hz, 1H), 2.71 (dtd, J = 12.9,
7.5, 5.1 Hz, 1H), 2.22 (ddd, J = 13.7, 8.2, 5.3 Hz, 1H), 2.16−2.00 (m,
3H), 1.86 (tt, J = 10.1, 5.3 Hz, 1H), 1.65 (dtt, J = 14.9, 9.7, 4.6 Hz,
2H), 1.50 (dtd, J = 11.3, 6.4, 3.3 Hz, 1H); 13C NMR (75 MHz,
CDCl3) δ 149.5, 145.4, 138.8, 138.1, 133.8, 129.2, 128.6, 128.3, 126.3,
125.6, 125.1, 122.2, 121.4, 121.0, 119.6, 111.6, 65.7, 53.1, 40.5, 37.1,
32.5, 29.7, 29.5, 21.1; HRMS (ESI) m/z calcd for C25H26ClN2O2S [M
+ H]+ 453.1398, found 453.1404; IR (thin film) 3355, 3289, 3056,
2929, 2856, 1718, 1638, 1586, 1519, 1445, 1265, 1161, 1094, 1014,
901, 803, 752 cm−1.
dro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (6k). TLC
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.60; light yellow oil, 88%; H
NMR (500 MHz, CDCl3) δ 7.76 (d, J = 8.6 Hz, 2H), 7.50 (d, J = 8.6
Hz, 2H), 7.08 (d, J = 1.9 Hz, 1H), 6.79 (d, J = 1.9 Hz, 1H), 4.95 (d, J
= 1.4 Hz, 1H), 4.81 (t, J = 6.3 Hz, 1H), 4.67 (s, 1H), 3.89 (brs, 1H),
3.69 (t, J = 4.8 Hz, 1H), 3.02−2.88 (m, 2H), 2.19−2.14 (m, 2H),
2.11−2.01 (m, 1H), 1.99−1.93 (m, 1H), 1.87−1.77 (m, 1H), 1.73−
1.64 (m, 2H), 1.53−1.50 (m, 1H); 13C NMR (75 MHz, CDCl3) δ
147.9, 145.7, 139.3, 138.3, 135.8, 129.5, 128.5, 127.4, 123.5, 122.7,
116.0, 112.4, 65.2, 53.3, 40.1, 36.1, 32.3, 28.5, 21.4; HRMS (ESI) m/z
calcd for C21H21Cl3N2NaO2S [M + Na]+ 493.0282, found 493.0292;
IR (thin film) 3360, 3291, 2926, 2855, 1714, 1638, 1580, 1464, 1329,
1161, 1094, 904, 754 cm−1.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
N-[2-(8-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
1H-carbazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (6l). TLC
bazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (6g). TLC (hex-
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 77%; H
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.40; light yellow oil, 83%; H NMR
NMR (500 MHz, CDCl3) δ 7.76 (d, J = 8.6 Hz, 2H), 7.50 (d, J = 8.6
Hz, 2H), 7.02 (dd, J = 9.5, 1.7 Hz, 1H), 6.84 (d, J = 1.7 Hz, 1H), 4.96
(d, J = 1.4 Hz, 1H), 4.76 (t, J = 6.3 Hz, 1H), 4.67 (s, 1H), 3.74 (brs,
1H), 3.69 (t, J = 4.9 Hz, 1H), 3.04−2.85 (m, 2H), 2.21−2.12 (m, 2H),
2.10−2.03 (m, 1H), 2.02−1.94 (m, 1H), 1.86−1.78 (m, 1H), 1.72−
1.63 (m, 2H), 1.55−1.49 (m, 1H); 13C NMR (75 MHz, CDCl3) δ
150.8, 148.1, 147.5, 139.2, 138.3, 138.2, 138.2, 136.3, 136.1, 129.5,
128.5, 128.5, 128.1, 122.8, 122.8, 118.2, 117.9, 112.4, 109.7, 109.6,
66.0, 52.9, 52.9, 40.1, 36.0, 32.4, 28.5, 21.6; HRMS (ESI) m/z calcd for
C21H22BrClFN2O2S [M + H]+ 499.0252, found 499.0258; IR (thin
film) 3359, 3303, 2927, 2854, 1705, 1623, 1588, 1520, 1472, 1396,
1330, 1261, 1161, 1094, 1014, 903, 828, 753 cm−1.
(500 MHz, CDCl3) δ 7.85−7.64 (m, 2H), 7.48 (d, J = 8.8 Hz, 2H),
7.22 (d, J = 8.0 Hz, 1H), 6.86 (d, J = 7.2 Hz, 1H), 6.63 (t, J = 7.6 Hz,
1H), 4.94 (s, 1H), 4.88 (t, J = 6.2 Hz, 1H), 4.68 (s, 1H), 3.71−3.63
(m, 1H), 3.06−2.85 (m, 2H), 2.16 (q, J = 5.6 Hz, 2H), 2.07 (q, J = 9.1,
8.3 Hz, 1H), 1.99 (ddd, J = 14.2, 8.5, 5.6 Hz, 1H), 1.82 (ddt, J = 12.3,
8.3, 5.0 Hz, 1H), 1.67 (dtt, J = 16.8, 9.8, 5.0 Hz, 2H), 1.50 (ddt, J =
13.8, 10.2, 6.1 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ 148.6, 139.1,
138.4, 130.6, 129.4, 128.5, 122.9, 120.2, 112.1, 64.7, 53.4, 40.3, 36.4,
32.4, 28.7, 21.5; HRMS (ESI) m/z calcd for C21H23BrClN2O2S [M +
H]+ 481.0347, found 491.0350; IR (thin film) 3373, 3054, 2927, 2853,
1588, 1454, 1422, 1265, 1164, 1098, 897, 829 cm−1.
N-[2-(7-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
Benzyl N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-
bazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (6h). TLC (hex-
1H-carbazol-4a-yl)ethyl]carbamate (10a). TLC (hexanes:ethyl
1
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.30; light yellow oil, 86%; H NMR
acetate, 2:1 v/v) Rf = 0.30; light yellow oil, 95%; H NMR (500
(500 MHz, CDCl3) δ 7.73 (d, J = 8.5 Hz, 2H), 7.49 (d, J = 8.5 Hz,
2H), 6.89−6.82 (m, 1H), 6.78−6.64 (m, 2H), 4.93 (s, 1H), 4.76 (t, J =
6.3 Hz, 1H), 4.67 (s, 1H), 3.70 (brs, 1H), 3.62 (t, J = 4.8 Hz, 1H),
3.03−2.84 (m, 2H), 2.24−2.10 (m, 2H), 2.07−2.01 (m, 1H), 1.99−
1.93 (m, 1H), 1.84−1.72 (m, 1H), 1.69−1.60 (m, 2H), 1.53−1.46 (m,
1H); 13C NMR (75 MHz, CDCl3) δ 151.2, 148.8, 139.1, 138.4, 132.0,
129.4, 128.5, 125.3, 121.7, 121.6, 113.4, 112.0, 65.3, 51.8, 40.2, 36.3,
32.3, 28.7, 21.5; HRMS (ESI) m/z calcd for C21H23BrClN2O2S [M +
H]+ 481.0347, found 481.0350; IR (thin film) 3367, 3285, 2925, 2854,
1713, 1600, 1478, 1434, 1328, 1161, 1094, 1014, 901, 828, 738 cm−1.
N-(2-((4aS,9aS)-5-Bromo-4-methylene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl)-4-chlorobenzenesulfonamide (6i). TLC
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.30; colorless oil, 73%; 1H
NMR (500 MHz, CDCl3) δ 7.73 (d, J = 8.5 Hz, 2H), 7.49 (d, J = 8.5
Hz, 2H), 6.89−6.82 (m, 1H), 6.78−6.64 (m, 2H), 4.93 (s, 1H), 4.76
(t, J = 6.3 Hz, 1H), 4.67 (s, 1H), 3.70 (brs, 1H), 3.62 (t, J = 4.8 Hz,
1H), 3.03−2.84 (m, 2H), 2.24−2.10 (m, 2H), 2.07−2.01 (m, 1H),
1.99−1.93 (m, 1H), 1.84−1.72 (m, 1H), 1.69−1.60 (m, 2H), 1.53−
1.46 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 153.1, 150.6, 149.0,
136.1, 135.4, 131.4, 130.0, 129.5, 128.5, 123.2, 111.9, 111.3, 64.8, 50.6,
41.2, 39.9, 32.8, 29.3, 22.4; HRMS (ESI) m/z calcd for
C21H22BrClN2NaO2S [M + Na]+ 503.0166, found 503.0170; IR
MHz, CDCl3) δ 7.41−7.31 (m, 5H), 7.15 (d, J = 7.1 Hz, 2H), 6.55 (d,
J = 8.6 Hz, 1H), 5.09 (s, 2H), 4.94 (s, 1H), 4.83 (brs, 1H), 4.71 (s,
1H), 3.74 (t, J = 4.4 Hz, 1H), 3.39−3.26 (m, 1H), 3.22−3.15 (m, 1H),
2.21−2.19 (m, 2H), 2.10−2.04 (m, 1H), 2.00−1.94 (m, 1H), 1.87−
1.80 (m, 1H), 1.71−1.66 (m, 3H), 1.57−1.52 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 156.3, 149.0, 148.9, 136.3, 130.5, 128.5, 128.1, 127.2,
112.0, 111.7, 110.4, 66.7, 65.3, 52.3, 38.0, 35.7, 32.3, 28.2, 21.8; HRMS
(ESI) m/z calcd for C23H25BrN2NaO2 [M + Na]+ 464.0092, found
464.1006; IR (thin film) 3344, 3032, 2924, 2853, 1711, 1601, 1519,
1473, 1375, 1259, 1102, 902, 807 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]pentanamide (12b). TLC (chloroform:methanol,
10:1 v/v) Rf = 0.75; light yellow oil, 82%; 1H NMR (500 MHz,
CDCl3) δ 7.16 (d, J = 6.7 Hz, 2H), 6.55 (d, J = 8.9 Hz, 1H), 5.45 (brs,
1H), 4.94 (d, J = 1.4 Hz, 1H), 4.72 (s, 1H), 3.99 (brs, 1H), 3.76 (t, J =
4.4 Hz, 1H), 3.44−3.38 (m, 1H), 3.28−3.16 (m, 1H), 2.36 (t, J = 7.5
Hz, 1H), 2.23−2.20 (m, 1H), 2.14−2.08 (m, 2H), 2.08−2.00 (m, 1H),
1.99−1.92 (m, 1H), 1.87−1.79 (m, 1H), 1.75−1.66 (m, 2H), 1.65−
1.57 (m, 2H), 1.33 (dq, J = 14.6, 7.3 Hz, 2H), 0.91 (t, J = 7.3 Hz, 3H);
13C NMR (75 MHz, CDCl3) δ 173.1, 140.4, 131.5, 131.0, 114.3, 104.5,
66.4, 52.0, 38.3. 36.6, 36.2, 34.9, 32.7, 29.8, 27.7, 27.2, 22.6, 14.1;
HRMS (ESI) m/z calcd for C20H28BrN2O [M + H]+ 391.1380, found
3813
dx.doi.org/10.1021/jm500146g | J. Med. Chem. 2014, 57, 3803−3817

Journal of Medicinal Chemistry
Article
391.1368; IR (thin film) 3312, 3084, 2955, 2930, 2860, 1727, 1661,
1587, 1542, 1467, 1392, 1325, 1254, 1202, 909, 821 cm−1.
film) 3290, 3088, 2924, 2853, 1712, 1638, 1574, 1468, 1389, 1359,
1339, 1231, 1167, 1092, 1068, 1010, 908, 821, 738 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-chlorobenzamide (12c). TLC (hexanes:ethyl
acetate, 1:1 v/v) Rf = 0.70; light yellow oil, 97%; 1H NMR (500
MHz, CDCl3) δ 7.59 (d, J = 8.5 Hz, 2H), 7.39 (d, J = 8.5 Hz, 2H),
7.20 (d, J = 2.0 Hz, 1H), 7.17 (dd, J = 8.2, 2.0 Hz, 1H), 6.57 (d, J = 8.2
Hz, 1H), 6.24 (brs, 1H), 4.98 (d, J = 1.5 Hz, 1H), 4.77 (s, 1H), 3.80 (t,
J = 4.5 Hz, 1H), 3.60−3.57 (m, 1H), 3.52−3.42 (m, 1H), 2.32−2.20
(m, 2H), 2.19−2.15 (m, 1H), 2.12−2.06 (m, 1H), 1.88−1.81 (m, 1H),
1.74−1.67 (m, 2H), 1.58−1.53 (tm, 1H); 13C NMR (75 MHz,
CDCl3) δ 166.2, 149.2, 149.1, 137.6, 136.2, 132.8, 130.6, 128.8, 128.8,
128.2, 127.1, 112.1, 111.8, 110.5, 65.2, 52.3, 37.1, 35.3, 32.3, 28.4, 21.6;
HRMS (ESI) m/z calcd for C22H22BrClN2NaO [M + Na]+ 467.0496,
found 467.0498; IR (thin film) 3309, 2927, 2855, 1636, 1597, 1567,
1544, 1485, 1316, 1262, 1094, 1013, 976 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-iodobenzene-1-sulfonamide (12h). TLC (hex-
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.50; yellow oil, 92%; H NMR (500
MHz, CDCl3) δ 7.88 (d, J = 8.5 Hz, 2H), 7.53 (d, J = 8.5 Hz, 2H),
7.15 (dd, J = 8.3, 2.0 Hz, 1H), 6.99 (d, J = 2.0 Hz, 1H), 6.53 (d, J = 8.2
Hz, 1H), 4.94 (d, J = 1.3 Hz, 1H), 4.92 (brs, 1H), 4.68 (d, J = 1.2 Hz,
1H), 3.62 (t, J = 4.9 Hz, 1H), 3.01−2.86 (m, 2H), 2.21−2.10 (m, 2H),
2.05−2.01 (m, 1H), 1.98−1.92 (m, 1H), 1.82−1.76 (m, 1H), 1.67−
1.57 (m, 2H), 1.51−1.46 (m, 1H); 13C NMR (75 MHz, CDCl3) δ
148.8, 148.6, 139.6, 138.4, 135.4, 130.7, 128.4, 127.0, 112.2, 111.9,
110.7, 100.0, 65.4, 52.3, 40.2, 36.3, 32.4, 29.7, 21.6; HRMS (ESI) m/z
calcd for C21H22BrIN2NaO2S [M + Na]+ 594.9522, found 594.9523;
IR (thin film) 3283, 3082, 2926, 2855, 1716, 1636, 1601, 1570, 1474,
1384, 1329, 1262, 1161, 1090, 1006, 816, 737 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]benzenesulfonamide (12d). TLC (hexanes:ethyl
acetate, 1:1 v/v) Rf = 0.50; light yellow oil, 77%; 1H NMR (500 MHz,
CDCl3) δ 7.87−7.79 (m, 2H), 7.62−7.57 (m, 1H), 7.53 (t, J = 7.6 Hz,
2H), 7.13 (dd, J = 8.2, 2.0 Hz, 1H), 6.98 (d, J = 2.0 Hz, 1H), 6.52 (d, J
= 8.2 Hz, 1H), 4.91 (s, 1H), 4.89 (brs, 1H), 4.63 (s, 1H), 3.62 (t, J =
4.8 Hz, 1H), 3.04−2.91 (m, 2H), 2.15−2.13 (m, 2H), 2.05−1.97 (m,
1H), 1.97−1.90 (m, 1H), 1.79−1.74 (m, 1H), 1.66−1.61 (m, 2H),
1.53−1.45 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.8, 148.7,
139.8, 135.6, 132.7, 130.6, 129.2, 128.8, 128.2, 127.0, 112.1, 111.8,
110.6, 65.3, 52.3, 40.2, 36.1, 32.4, 28.5, 21.7; HRMS (ESI) m/z calcd
for C21H24BrN2O2S [M + H]+ 447.0736, found 448.0742; IR (thin
film) 3361.8, 2926, 2855, 1638, 1598, 1475, 1324, 1159, 1092, 902,
689 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-3,4-dichlorobenzene-1-sulfonamide (12i). TLC
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.50; light yellow oil, 72%; H
NMR (500 MHz, CDCl3) δ 7.91 (d, J = 2.0 Hz, 1H), 7.63 (dd, J = 8.4,
2.1 Hz, 1H), 7.60 (s, 1H), 7.15 (dd, J = 8.3, 2.0 Hz, 1H), 7.00 (d, J =
2.0 Hz, 1H), 6.54 (d, J = 8.3 Hz, 1H), 5.12 (t, J = 6.3 Hz, 1H), 4.97 (d,
J = 1.4 Hz, 1H), 4.72 (s, 1H), 3.74 (s, 1H), 3.63 (t, J = 5.1 Hz, 1H),
3.07−2.95 (m, 1H), 2.93−2.83 (m, 1H), 2.21−2.11 (m, 2H), 2.08−
2.01 (m, 1H), 2.00−1.94 (m, 1H), 1.84−1.77 (m, 1H), 1.68−1.56 (m,
2H), 1.53−1.43 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.7, 148.4,
139.7, 137.5, 135.3, 133.8, 131.2, 131.2, 130.8, 128.9, 128.6, 126.9,
126.1, 125.6, 112.2, 111.9, 110.9, 65.4, 52.4, 40.3, 36.5, 32.5, 29.0, 21.6;
HRMS (ESI) m/z calcd for C21H22BrCl2N2O2S [M + H]+ 514.9957,
found 514.9963; IR (thin film) 2268, 2960, 2337, 1720, 1601, 1455,
1370, 1260, 1164, 1032, 801, 700 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-methylbenzene-1-sulfonamide (12e). TLC
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 80%; H
bazol-4a-yl)ethyl]-2,4-dichlorobenzene-1-sulfonamide (12j). TLC
1
NMR (500 MHz, CDCl3) δ 7.71 (d, J = 8.3 Hz, 2H), 7.33 (d, J = 8.3
Hz, 2H), 7.30 (dd, J = 8.2, 2.1 Hz, 2H), 6.94 (d, J = 2.1 Hz, 1H), 5.09
(d, J = 2.1 Hz, 1H), 4.80 (d, J = 2.0 Hz, 1H), 3.97 (dd, J = 8.1, 5.8 Hz,
1H), 3.55 (t, J = 6.2 Hz, 1H), 2.79−2.72 (m, 1H), 2.55−2.49 (m, 1H),
2.46 (s, 3H), 2.23 (dt, J = 15.2, 5.0 Hz, 1H), 2.05−2.01 (m, 1H),
1.96−1.86 (m, 1H), 1.71−1.55 (m, 4H), 1.52−1.46 (1, 1H); 13C
NMR (75 MHz, CDCl3) δ 144.7, 139.4, 136.7, 135.9, 131.8, 130.1,
127.0. 126.8, 126.7, 117.1, 113.6, 67.8, 52.1, 38.7, 38.4, 31.8, 29.7, 21.6;
HRMS (ESI) m/z calcd for C22H25BrKN2O2S [M + K]+ 499.0452,
found 499.0455; IR (thin film) 3292, 3064, 2924, 2854, 1724, 1683,
1597, 1465, 1356, 1334, 1184, 1162, 1094, 908, 815, 665 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-fluorobenzene-1-sulfonamide (12f). TLC (hex-
(hexanes:ethyl acetate, 2:1 v/v) Rf = 0.40; light yellow oil, 77%; H
NMR (500 MHz, CDCl3) δ 8.16−8.03 (m, 1H), 7.87 (dd, J = 6.9, 2.4
Hz, 1H), 7.82−7.67 (m, 2H), 7.14 (dd, J = 8.3, 2.0 Hz, 1H), 7.02 (d, J
= 2.1 Hz, 1H), 6.55 (d, J = 8.3 Hz, 1H), 5.82 (t, J = 6.1 Hz, 1H), 4.96
(s, 1H), 4.71 (s, 1H), 3.68 (t, J = 5.0 Hz, 1H), 3.21−2.99 (m, 3H),
2.26−2.15 (m, 2H), 2.15−2.08 (m, 1H), 2.06−2.00 (m, 1H), 1.87−
1.80 (m, 1H), 1.74−1.62 (m, 2H), 1.55−1.46 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 148.9, 141.7, 139.5, 135.3, 132.3, 131.3, 130.7, 127.6,
126.8, 112.1, 111.9, 111.0, 65.2, 52.3, 40.2, 36.2, 32.4, 31.1, 21.8;
HRMS (ESI) m/z calcd for C21H21BrCl2N2NaO2S [M + Na]+
536.9776, found 536.9794; IR (thin film) 3292, 3087, 2924, 2853,
1712, 1637, 1600, 1572, 1555, 1456, 1373, 1337, 1260, 1166, 1102,
903, 817, 624 cm−1.
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-4-cyanobenzene-1-sulfonamide (12k). TLC
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20; colorless oil, 67%; 1H
NMR (500 MHz, CDCl3) δ 7.93 (d, J = 8.4 Hz, 2H), 7.83 (d, J = 8.4
Hz, 2H), 7.16 (dd, J = 8.3, 2.0 Hz, 1H), 6.99 (d, J = 2.0 Hz, 1H), 6.54
(d, J = 8.2 Hz, 1H), 5.13 (brs, 1H), 4.97 (s, 1H), 4.71 (s, 1H), 3.62 (t,
J = 5.1 Hz, 1H), 3.04−2.90 (m, 2H), 2.24−2.10 (m, 2H), 2.09−2.01
(m, 1H), 1.99−1.92 (m, 1H), 1.83−1.78 (m, 1H), 1.67−1.61 (m, 2H),
1.50−1.46 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 148.8, 148.4,
144.3, 135.2, 133.0, 130.8, 127.6, 126.9, 117.3, 116.4, 112.2, 111.9,
110.8, 65.4, 52.3, 40.3, 36.6, 32.5, 29.7, 29.0, 21.6; HRMS (ESI) m/z
calcd for C22H23BrN3O2S [M + H]+ 472.0689, found 472.0696; IR
(thin film) 3364, 2923, 2864, 2844, 1653, 1474, 1332, 1275, 1260,
1161, 1054, 1016, 750, 634 cm−1.
1
anes:ethyl acetate, 3:1 v/v) Rf = 0.20; light yellow oil, 70%; H NMR
(500 MHz, CDCl3) δ 7.90 (dd, J = 8.6, 5.0 Hz, 2H), 7.81 (dd, J = 8.8,
5.1 Hz, 2H), 7.50 (d, J = 8.5 Hz, 1H), 7.39−7.34 (m, 1H), 6.98 (d, J =
2.0 Hz, 1H), 5.11 (s, 1H), 4.85 (s, 1H), 4.17 (brs,, 1H), 4.12 (dd, J =
8.0, 5.7 Hz, 1H), 2.81−2.76 (m, 1H), 2.73−2.66 (m, 1H), 2.28−2.17
(m, 2H), 2.08−1.98 (m, 1H), 1.93 (q, J = 8.9, 8.4 Hz, 1H), 1.95−1.89
(m, 1H), 1.73−1.64 (m, 2H), 1.44−1.41 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 144.9, 139.3, 138.4, 131.8, 129.8, 129.7, 129.6, 129.6,
127.0, 117.0, 116.9, 116.68, 116.7, 116.6, 116.3, 113.5, 68.3, 52.1, 39.0,
38.2, 31.6, 30.0, 20.0; HRMS (ESI) m/z calcd for C21H22BrFN2NaO2S
[M + Na]+ 487.0462, found 487.0481; IR (thin film) 3298, 3077,
2926, 2855, 1712, 1651, 1592, 1493, 1469, 1358, 1337, 1293, 1238,
907, 839, 738 cm−1.
4-Bromo-N-[2-(6-bromo-4-methylidene-2,3,4,4a,9,9a-hexahy-
dro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (12g). TLC
N-(4-{[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-
1
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.30; light yellow oil, 81%; H
carbazol-4a-yl)ethyl]sulfamoyl}phenyl)acetamide (12l). TLC (hex-
1
NMR (500 MHz, CDCl3) δ 7.76−7.59 (m, 4H), 7.19 (d, J = 8.3 Hz,
1H), 7.02 (d, J = 2.0 Hz, 1H), 6.63 (s, 1H), 4.98 (s, 1H), 4.71 (s, 1H),
3.81−3.68 (m, 1H), 3.02−2.90 (m, 2H), 2.26−2.16 (m, 1H), 2.15−
2.09 (m, 1H), 2.09−2.01 (m, 1H), 2.00−1.94(m, 1H), 1.70−1.64 (m,
2H), 1.50−1.44 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 149.7, 144.9,
139.3, 139.0, 138.3, 132.9, 132.1, 131.9, 128.4, 127.1, 117.1, 116.7,
114.9, 68.5, 52.1, 39.3, 32.0, 31.6, 30.3, 20.0; HRMS (ESI) m/z calcd
for C21H23Br2N2O2S [M + H]+ 524.9842, found 524.9839; IR (thin
anes:ethyl acetate, 1:3 v/v) Rf = 0.30; colorless oil, 74%; H NMR
(500 MHz, CDCl3) δ 7.76 (d, J = 8.8 Hz, 2H), 7.67 (d, J = 8.8 Hz,
2H), 7.13 (dd, J = 8.2, 2.0 Hz, 1H), 6.99 (d, J = 2.0 Hz, 1H), 6.52 (d, J
= 8.2 Hz, 1H), 4.92 (d, J = 1.4 Hz, 1H), 4.82 (t, J = 6.3 Hz, 1H), 4.65
(s, 1H), 3.62 (t, J = 4.8 Hz, 1H), 2.94 (q, J = 7.2 Hz, 2H), 2.23 (s,
3H), 2.17−2.14 (m, 2H), 2.05−2.00 (m, 1H), 1.97−1.91 (m, 1H),
1.80−1.75 (m, 1H), 1.69−1.64 (m, 2H), 1.50 (dt, J = 11.7, 6.0 Hz,
1H); 13C NMR (75 MHz, CDCl3) δ 169.0, 148.4, 142.1, 135.9, 132.2,
3814
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Article
130.8, 130.1, 128.3, 127.9, 127.2, 119.6, 112.3, 112.1, 65.1, 52.4, 39.9,
35.9, 32.3, 24.8, 21.5; HRMS (ESI) m/z calcd for C23H26BrKN3O3S
[M + K]+ 542.0510, found 542.0515; IR (thin film) 3318, 3056, 2925,
2854, 1678, 1592, 1533, 1488, 1401, 1371, 1321, 1264, 1155, 094,
1005, 824, 725 cm−1.
118.1, 117.8, 114.3, 112.38, 109.5, 109.4, 65.9, 55.6, 52.9, 52.9, 40.1,
35.7, 32.3, 28.3, 21.7; HRMS (ESI) m/z calcd for C22H25BrFN2O3S
[M + H]+ 495.0748, found 495.0754; IR (thin film) 3054, 2986, 2924,
2850, 1597, 1421, 1265, 1157, 1094, 896, 835, 740 cm−1.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-4-methylbenzene-1-sulfonamide (13b).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.50; colorless oil, 83%;
1H NMR (500 MHz, CDCl3) δ 7.72 (d, J = 8.3 Hz, 2H), 7.33 (d, J =
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]pyridine-2-sulfonamide (12m). TLC (chloroform:-
methanol, 10:1 v/v) Rf = 0.50; colorless oil, 77%; 1H NMR (500 MHz,
CDCl3) δ 8.82−8.65 (m, 1H), 8.01 (d, J = 7.9 Hz, 1H), 7.94 (td, J =
7.7, 1.7 Hz, 1H), 7.52 (ddd, J = 7.5, 4.7, 1.3 Hz, 1H), 7.13 (dd, J = 8.3,
2.0 Hz, 1H), 7.01 (d, J = 2.0 Hz, 1H), 6.54 (d, J = 8.2 Hz, 1H), 5.32 (t,
J = 6.1 Hz, 1H), 4.92 (s, 1H), 4.64 (s, 1H), 3.68 (t, J = 4.7 Hz, 1H),
3.07 (dtd, J = 8.7, 6.2, 2.1 Hz, 2H), 2.16−2.15 (m, 2H), 2.11−2.04 (m,
1H), 2.02−1.96 (m, 1H), 1.88−1.76 (m, 1H), 1.70−1.65 (m, 2H),
1.56−1.49 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 157.4, 150.1,
148.9, 148.8, 138.1, 135.7, 130.6, 127.0, 126.7, 122.3, 112.1, 111.8,
110.6, 110.5, 65.3, 52.3, 40.7, 36.0, 32.4, 28.4, 21.8; HRMS (ESI) m/z
calcd for C20H23BrN3O2S [M + H]+ 448.0689, found 448.0695; IR
(thin film) 3363, 2926, 2854, 1720, 1637, 1578, 1474, 1426, 1331,
1174, 902, 811 cm−1.
8.0 Hz, 2H), 7.01 (dd, J = 9.6, 1.7 Hz, 1H), 6.84 (d, J = 1.7 Hz, 1H),
4.93 (d, J = 1.5 Hz, 1H), 4.63 (d, J = 7.6 Hz, 1H), 3.73 (brs, 1H), 3.70
(t, J = 4.7 Hz, 1H), 3.02−2.90 (m, 2H), 2.45 (s, 3H), 2.16 (dd, J = 7.6,
4.7 Hz, 2H), 2.05 (dt, J = 14.0, 7.9 Hz, 1H), 1.96 (dt, J = 14.5, 7.4 Hz,
1H), 1.81 (td, J = 10.9, 5.4 Hz, 1H), 1.75−1.65 (m, 1H), 1.52 (tt, J =
10.3, 4.8 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ 148.2, 143.6, 138.4,
136.7, 129.8, 129.0, 127.1, 122.9, 122.8, 118.1, 117.9, 112.4, 65.9, 52.9,
40.1, 35.8, 32.3, 28.3, 21.7, 21.6; HRMS (ESI) m/z calcd for
C22H25BrFN2O2S [M + H]+ 479.0799, found 479.0793; IR (thin film)
3054, 2925, 2850, 1422, 1265, 971, 896, 741 cm−1.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-4-fluorobenzene-1-sulfonamide (13c).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20; light yellow oil,
72%; 1H NMR (500 MHz, CDCl3) δ 7.95−7.80 (m, 2H), 7.21 (dd, J =
9.5, 7.6 Hz, 2H), 7.02 (dd, J = 9.6, 1.7 Hz, 1H), 6.84 (d, J = 1.8 Hz,
1H), 4.95 (s, 1H), 4.81 (t, J = 6.3 Hz, 1H), 4.66 (s, 1H), 3.76 (brs,
1H), 3.70 (t, J = 4.8 Hz, 1H), 3.00−2.90 (m, 1H), 2.21−2.12 (m, 1H),
2.11−2.02 (m, 1H), 2.00−1.94 (m, 1H), 1.89−1.78 (m, 1H), 1.71−
1.64 (m, 2H), 1.57−1.47 (m, 1H); 13C NMR (101 MHz, CDCl3) δ
150.7, 148.1, 147.5, 138.2, 138.2, 136.3, 136.2, 135.8, 135.8, 129.8,
129.7, 122.8, 122.8, 118.2, 117.9, 116.6, 116.3, 112.4, 109.7, 109.6,
66.0, 52.9, 52.9, 40.1, 36.0, 32.4, 28.5, 21.6; HRMS (ESI) m/z calcd for
C21H22BrF2N2NaO2S [M + Na]+ 483.0548, found 483.0553; IR (thin
film) 3054, 2986, 2925, 2849, 1593, 1495, 1469, 1265, 896, 840 cm−1.
4-Bromo-N-[2-(6-bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-
hexahydro-1H-carbazol-4a-yl)ethyl]benzene-1-sulfonamide (13d).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.40; light yellow oil,
81%; 1H NMR (500 MHz, CDCl3) δ 7.75−7.60 (m, 4H), 6.99 (d, J =
9.5 Hz, 1H), 6.82 (s, 1H), 4.93 (s, 1H), 4.82 (t, J = 6.3 Hz, 1H), 4.64
(s, 1H), 3.73 (brs, 1H), 3.66 (t, J = 4.9 Hz, 1H), 2.91 (ddd, J = 10.0,
8.1, 5.1 Hz, 2H), 2.13 (q, J = 5.2 Hz, 2H), 2.02 (q, J = 7.9, 7.4 Hz,
1H), 1.94 (ddd, J = 14.4, 8.3, 6.2 Hz, 1H), 1.79 (td, J = 12.4, 11.3, 5.8
Hz, 1H), 1.64 (p, J = 6.4, 5.8 Hz, 2H), 1.49 (dq, J = 12.7, 6.3 Hz, 1H);
13C NMR (75 MHz, CDCl3) δ 150.8, 148.0, 147.5, 138.8, 138.2, 138.1,
N-[2-(6-Bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-car-
bazol-4a-yl)ethyl]-2-nitrobenzene-1-sulfonamide (12n). TLC (hex-
1
anes:ethyl acetate, 1:1 v/v) Rf = 0.50; yellow oil, 87%; H NMR (500
MHz, CDCl3) δ 8.16−8.03 (m, 1H), 7.87 (dd, J = 6.9, 2.4 Hz, 1H),
7.82−7.67 (m, 2H), 7.14 (dd, J = 8.3, 2.0 Hz, 1H), 7.02 (d, J = 2.1 Hz,
1H), 6.55 (d, J = 8.3 Hz, 1H), 5.82 (t, J = 6.1 Hz, 1H), 4.96 (s, 1H),
4.71 (s, 1H), 3.68 (t, J = 5.0 Hz, 1H), 3.21−2.99 (m, 3H), 2.26−2.15
(m, 2H), 2.15−2.08 (m, 1H), 2.06−2.00 (m, 1H), 1.87−1.80 (m, 1H),
1.74−1.62 (m, 2H), 1.55−1.46 (m, 1H); 13C NMR (75 MHz, CDCl3)
δ 148.9, 148.6, 135.4, 133.7, 133.5, 132.8, 131.0, 130.7, 126.9, 125.4,
112.1, 111.8, 110.6, 65.4, 52.4, 46.0, 40.7, 36.4, 32.5, 28.7, 21.7; HRMS
(ESI) m/z calcd for C21H22BrKN3O4S [M + K]+ 530.0146, found
530.0151; IR (thin film) 3367, 3091, 2932, 2857, 2360, 1735, 1600,
1540, 1475, 1422, 1362, 1342, 1261, 1166, 812, 738 cm−1.
2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-
carbazol-4a-yl)ethan-1-amine (11b). TLC (choloroform:methanol,
1
10:1 v/v) Rf = 0.10; yellow oil, 81%; H NMR (500 MHz, CDCl3) δ
7.01 (d, J = 9.0 Hz, 2H), 4.88 (s, 1H), 4.58 (s, 1H), 3.76 (t, J = 4.1 Hz,
1H), 2.81 (dt, J = 11.5, 5.6 Hz, 1H), 2.68 (td, J = 12.0, 11.3, 5.2 Hz,
1H), 2.20 (dt, J = 8.9, 4.8 Hz, 2H), 2.01 (ddd, J = 13.9, 10.9, 5.4 Hz,
1H), 1.94−1.88 (m, 1H), 1.85−1.69 (m, 3H), 1.62−1.58 (m, 1H); 13C
NMR (75 MHz, CDCl3) δ 150.7, 149.2, 147.5, 139.7, 139.6, 136.5,
136.3, 123.3, 123.2, 117.7, 117.4, 111.8, 109.1, 109.0, 66.2, 53.1, 53.1,
39.1, 38.8, 32.2, 27.5, 21.9; HRMS (ESI) m/z calcd for C15H19BrFN2
[M + H]+ 325.0710, found 325.0714; IR (thin film) 3369, 2931, 2857,
1636, 1591, 1471, 1315, 848 cm−1.
136.3, 136.1, 132.5, 128.6, 127.7, 122.8, 122.8, 118.2, 118.0, 112.5,
109.7, 109.6, 66.0, 52.9, 52.9, 40.1, 36.0, 32.4, 28.5, 21.6; HRMS (ESI)
m/z calcd for C21H22Br2N2O2S [M + H]+ 542.9747, found 542.9751;
IR (thin film) 3773, 2929, 2859, 1620, 1528, 1327, 1260, 1222, 1161,
1068, 1010, 902, 822, 764 cm−1.
Benzyl N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hex-
ahydro-1H-carbazol-4a-yl)ethyl]carbamate (10b). TLC (hexane-
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1
s:ethyl acetate, 3:1 v/v) Rf = 0.40; light yellow oil, 92%; H NMR
1H-carbazol-4a-yl)ethyl]-4-iodobenzene-1-sulfonamide (13e). TLC
1
(500 MHz, CDCl3) δ 7.43−7.31 (m, 5H), 7.06−6.97 (m, 2H), 5.10 (s,
2H), 4.96 (s, 1H), 4.84 (t, J = 5.8 Hz, 1H), 4.70 (s, 1H), 3.79 (dd, J =
8.9, 4.9 Hz, 2H), 3.36−3.29 (m, 1H), 3.21−3.14 (m, 1H), 2.21 (t, J =
5.8 Hz, 2H), 2.11−2.05 (m, 1H), 2.01−1.97 (m, 1H), 1.85−1.83 (m,
1H), 1.78−1.69 (m, 2H), 1.60−1.54 (m, 1H); 13C NMR (75 MHz,
CDCl3) δ 156.3, 150.7, 148.5, 147.5, 139.0, 139.0, 136.5, 136.5, 136.3,
128.5, 128.1, 128.1, 123.1, 123.0, 118.0, 117.7, 112.3, 109.3, 109.2,
77.5, 77.1, 76.7, 66.7, 65.9, 52.8, 52.8, 38.0, 35.4, 32.3, 28.0, 21.8;
HRMS (ESI) m/z calcd for C23H25BrFN2O2 [M + H]+ 459.1078,
found 459.1085; IR (thin film) 3416, 3298, 2923, 2851, 1701, 1577,
1523, 1477, 1454, 1371, 1308, 1255, 1217, 1131, 882, 826 cm−1.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-4-methoxybenzene-1-sulfonamide (13a).
TLC (hexanes:ethyl acetate, 2:1 v/v) Rf = 0.20; light yellow oil,
91%; 1H NMR (500 MHz, CDCl3) δ 7.77 (d, J = 8.9 Hz, 2H), 7.10−
6.93 (m, 3H), 6.84 (d, J = 1.8 Hz, 1H), 4.93 (d, J = 1.5 Hz, 1H), 4.65
(t, J = 6.3 Hz, 1H), 4.62 (s, 1H), 3.89 (s, 3H), 3.75 (brs, 1H), 3.70 (t, J
= 4.6 Hz, 1H), 3.00−2.89 (m, 2H), 2.16 (t, J = 6.2 Hz, 2H), 2.09−2.01
(m, 1H), 1.99−1.93 (m, 1H), 1.85−1.78 (m, 1H), 1.71−1.64 (m, 2H),
1.56−1.51 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 162.9, 150.7,
148.2, 147.5, 138.4, 138.3, 136.4, 136.2, 131.2, 129.2, 122.9, 122.8,
(hexanes:ethyl acetate, 3:1 v/v) Rf = 0.50; yellow oil, 81%; H NMR
(500 MHz, CDCl3) δ 7.89 (d, J = 8.5 Hz, 2H), 7.54 (d, J = 8.5 Hz,
2H), 7.03 (dd, J = 9.5, 1.7 Hz, 1H), 6.85 (d, J = 1.7 Hz, 1H), 4.96 (d, J
= 1.5 Hz, 1H), 4.82 (t, J = 6.4 Hz, 1H), 4.67 (s, 1H), 3.75 (brs, 1H),
3.69 (t, J = 4.9 Hz, 1H), 3.00−2.88 (m, 2H), 2.23−2.12 (m, 2H),
2.09−2.03 (m, 1H), 2.00−1.95 (m, 1H), 1.87−1.78 (m, 1H), 1.72−
1.63 (m, 2H), 1.57−1.47 (m, 1H); 13C NMR (101 MHz, CDCl3) δ
150.3, 148.0, 147.9, 139.4, 138.4, 138.2, 138.1, 136.2, 136.1, 128.4,
122.8, 122.8, 118.2, 118.0, 112.5, 109.7, 109.6, 100.1, 65.9, 52.9, 52.8,
40.1, 36.0, 32.3, 28.5, 21.6; HRMS (ESI) m/z calcd for
C21H21BrFIN2NaO2S [M + Na]+ 590.9609, found 590.9616; IR
(thin film) 3054, 2986, 2918, 2849, 1624, 1571, 1471, 1336, 1265,
1163, 1125, 896, 819, 740 cm−1.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-3,4-dichlorobenzene-1-sulfonamide (13f).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.75; colorless oil, 80%; 1H
NMR (500 MHz, CDCl3) δ 7.92 (d, J = 2.1 Hz, 1H), 7.65 (dd, J = 8.4,
2.1 Hz, 1H), 7.61 (d, J = 8.4 Hz, 1H), 7.03 (dd, J = 9.5, 1.7 Hz, 1H),
6.86 (d, J = 1.8 Hz, 1H), 4.98 (d, J = 1.5 Hz, 1H), 4.94 (t, J = 6.3 Hz,
1H), 4.70 (s, 1H), 3.04−2.89 (m, 2H), 2.22−2.15 (m, 2H), 2.13−2.05
(m, 1H), 2.02−1.95 (m, 1H), 1.86−1.81 (m, 1H), 1.72−1.62 (m, 3H),
3815
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1.55−1.49 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 150.8, 147.9,
147.5, 139.7, 138.1, 138.0, 137.6, 136.3, 133.8, 131.2, 129.0, 126.0,
122.8, 122.7, 118.3, 118.0, 112.53, 109.8, 109.7, 66.0, 52.9, 52.9, 40.2,
36.2, 32.4, 28.7, 21.6; HRMS (ESI) m/z calcd for C21H21BrCl2FN2O2S
[M + H]+ 532.9863, found 532.9869; IR (thin film) 3365, 3085, 2925,
2855, 1624, 1560, 1456, 1333, 1203, 1164, 1059, 903, 820, 613 cm−1.
N-(4-{[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahy-
dro-1H-carbazol-4a-yl)ethyl]sulfamoyl}phenyl)acetamide (13g).
TLC (hexanes:ethyl acetate, 1:3 v/v) Rf = 0.50; colorless oil, 62%;
1H NMR (500 MHz, CDCl3) δ 7.78 (d, J = 8.8 Hz, 2H), 7.67 (d, J =
8.6 Hz, 2H), 7.43 (brs, 1H), 7.01 (dd, J = 9.6, 1.7 Hz, 1H), 6.85 (d, J =
1.8 Hz, 1H), 4.94 (s, 1H), 4.70 (t, J = 6.3 Hz, 1H), 4.63 (s, 1H), 3.75
(brs, 1H), 3.68 (t, J = 4.7 Hz, 1H), 2.98−2.90 (m, 2H), 2.24 (s, 4H),
2.18−2.15 (m, 2H), 2.08−2.02 (m, 1H), 1.99−1.93 (m, 1H), 1.85−
1.78 (m, 1H), 1.72−1.63 (m, 2H), 1.55−1.49 (m, 1H); 13C NMR (75
MHz, CDCl3) δ 168.6, 150.8, 148.1, 141.8, 138.3, 136.4, 136.2, 134.5,
128.4, 128.3, 122.8, 122.8, 119.4, 118.2, 117.9, 112.4, 65.9, 52.9, 40.1,
35.8, 32.3, 28.3, 24.8, 21.6; HRMS (ESI) m/z calcd for
C23H26BrFN3O3S [M + H]+ 522.0857, found 522.0857; IR (thin
film) 3243, 3092, 2980, 2944, 1695, 1591, 1473, 1399, 1371, 1317,
1261, 1158, 1035, 848, 763 cm−1.
ards Institutes; SAR, structure−activity relationship; DMSO,
dimethyl sulfoxide; TFA, trifluoroacetic acid; DMEM,
Dulbecco’s modified Eagle’s medium; FCS, fetal calf serum;
MHB, Mueller−Hinton broth; MIC, minimal inhibitory
concentration; MRC, minimum resensitizing concentration;
TLC, thin-layer chromatography; OD, optical density; IR,
infrared; mp, melting point.
REFERENCES
■
(1) Payne, D. J. Microbiology. Desperately seeking new antibiotics.
Science 2008, 321, 1644−1645.
(2) Lewis, K. Platforms for antibiotic discovery. Nat. Rev. Drug
Discovery 2013, 12, 371−387.
(3) Coates, A. R. M.; Halls, G.; Hu, Y. Novel classes of antibiotics or
more of the same? Br. J. Pharmacol. 2011, 163, 184−194.
(4) Lowy, F. D. Antimicrobial resistance: The example of
Staphylococcus aureus. J. Clin. Invest. 2003, 111, 1265−1273.
(5) Stryjewski, M. E.; Corey, G. R. Methicillin-resistant Staphylococcus
aureus: An evolving pathogen. Clin. Infect. Dis. 2014, 58, 10−19.
(6) Cohen, M. L. Epidemiology of drug resistance: Implications for a
post-antimicrobial era. Science 1992, 257, 1050−1055.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-4-cyanobenzene-1-sulfonamide (13h).
TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.20; colorless oil, 75%;
1H NMR (500 MHz, CDCl3) δ 7.94 (d, J = 8.4 Hz, 2H), 7.83 (d, J =
(7) Center for Disease Control and Prevention. Antibiotic Resistance
Threats; CDC: Atlanta, GA, 2013.
(8) Bal, A. M.; Garau, J.; Gould, I. M.; Liao, C. H.; Mazzei, T.;
Nimmo, G. R.; Soriano, A.; Stefani, S.; Tenover, F. C. Vancomycin in
the treatment of meticillin-resistant Staphylococcus aureus (MRSA)
infection: End of an era? J. Glob. Antimicrob. Resist. 2013, 1, 23−30.
8.4 Hz, 2H), 7.03 (dd, J = 9.5, 1.7 Hz, 1H), 6.84 (d, J = 1.8 Hz, 1H),
5.06 (brs, 1H), 4.98 (s, 1H), 4.70 (s, 1H), 3.77 (brs, 1H), 3.69 (t, J =
5.1 Hz, 1H), 3.03−2.89 (m, 2H), 2.27−2.11 (m, 2H), 2.10−2.04 (m,
1H), 2.02−1.96 (m, 1H), 1.86−1.81 (m, 1H), 1.74−1.63 (m, 2H),
1.54−1.47 (m, 1H); 13C NMR (75 MHz, CDCl3) δ 150.3, 147.9,
147.8, 144.1, 138.0, 137.9, 136.2, 136.1, 133.0, 127.6, 122.7, 122.7,
118.3, 118.1, 117.3, 116.4, 112.5, 109.8, 109.8, 66.0, 52.8, 52.8, 40.2,
36.3, 32.4, 28.8, 21.5; HRMS (ESI) m/z calcd for C22H22BrFN3O2S
[M + H]+ 490.0595, found 490.0600; IR (thin film) 3054, 2924, 2849,
1570, 1462, 1421, 1265, 1019, 971, 896, 740 cm−1.
(9) Abreu, A. C.; McBain, A. J.; Simoes, M. Plants as sources of new
̃
antimicrobials and resistance-modifying agents. Nat. Prod. Rep. 2012,
29, 1007−1021.
(10) Reading, C.; Cole, M. Clavulanic acid: A beta-lactamase-inhiting
beta-lactam from Streptomyces clavuligerus. Antimicrob. Agents Chemo-
ther. 1977, 11, 852−857.
(11) Rossolini, G. M. Acquired metallo-beta-lactamases: An
increasing clinical threat. Clin. Infect. Dis. 2005, 41, 1557−1558.
(12) Worthington, R. J.; Melander, C. Overcoming resistance to β-
lactam antibiotics. J. Org. Chem. 2013, 78, 4207−4213.
(13) Worthington, R. J.; Richards, J. J.; Melander, C. Small molecule
control of bacterial biofilms. Org. Biomol. Chem. 2012, 10, 7457−7474.
(14) Wang, H.; Gill, C. J.; Lee, S. H.; Mann, P.; Zuck, P.; Meredith,
T. C.; Murgolo; She, X.; Kales, S.; Liang, L.; Liu, J.; Wu, J.; Maria, J. S.;
Su, J.; Pan, J.; Hailey, J.; Mcguiness, D.; Tan, C. M.; Flattery, A.;
Walker, S.; Black, T.; Roemer, T. Discovery of wall teichoic acid
inhibitors as potential anti-MRSA β-lactam combination agents. Chem.
Biol. 2013, 20, 272−284.
N-[2-(6-Bromo-8-fluoro-4-methylidene-2,3,4,4a,9,9a-hexahydro-
1H-carbazol-4a-yl)ethyl]-4-(trifluoromethyl)benzene-1-sulfonamide
(13i). TLC (hexanes:ethyl acetate, 3:1 v/v) Rf = 0.40; light yellow oil,
71%; 1H NMR (500 MHz, CDCl3) δ 7.93 (d, J = 8.1 Hz, 2H), 7.77 (d,
J = 8.2 Hz, 2H), 6.99 (dd, J = 9.4, 1.7 Hz, 1H), 6.82 (d, J = 1.7 Hz,
1H), 4.94 (s, 2H), 4.66 (s, 1H), 3.73 (s, 1H), 3.66 (t, J = 5.1 Hz, 1H),
3.06−2.81 (m, 2H), 2.13 (dt, J = 12.4, 5.8 Hz, 2H), 2.09−1.90 (m,
2H), 1.86−1.73 (m, 1H), 1.68−1.61 (m, 2H), 1.47 (dd, J = 11.0, 5.8
Hz, 1H); 13C NMR (75 MHz, CDCl3) δ 150.8, 147.9, 147.5, 143.4,
138.1, 138.0, 136.3, 136.1, 134.7, 134.2, 127.5, 126.4, 126.4, 126.3,
126.3, 125.0, 122.8, 122.7, 121.4, 118.3, 118.0, 112.5, 109.8, 109.7,
66.0, 52.9, 52.9, 40.2, 36.3, 32.4, 28.7, 21.6; HRMS (ESI) m/z calcd for
C22H22BrF4N2O2S [M + H]+ 533.0516, found 533.0520; IR (thin film)
3054, 2987, 2926, 2853, 1559, 1507, 1421, 1323, 1265, 1063, 896, 740
cm−1.
(15) Pasquina, L. W.; Santa Maria, J. P.; Walker, S. Teichoic acid
biosynthesis as an antibiotic target. Curr. Opin. Microbiol. 2013, 16,
531−537.
(16) Podoll, J. D.; Liu, Y.; Chang, L.; Wall, S.; Wang, W.; Wang, X.
Bio-inspired synthesis yields a tricyclic indoline that selectively
resensitizes methicillin-resistant Staphylococcus aureus (MRSA) to β-
lactam antibiotics. Proc. Natl. Acad. Sci. U. S. A. 2013, 110, 15573−
15578.
(17) Clinical and Laboratory Standards Institute (CLSI). Performance
Standards for Antimicrobial Susceptibility Testing; 17th Informational
Supplement; CLSI: Wayne, PA, 2007.
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: xiang.wang@colorado.edu. Phone: (303) 492-6266.
Notes
The authors declare no competing financial interest.
(18) Yeo, S. J.; Liu, Y.; Wang, X. A one-pot three-component
reaction for the preparation of highly functionalized tryptamines.
Tetrahedron 2012, 68, 813−818.
(19) Liu, Y.; Xu, W.; Wang, X. Gold(I)-catalyzed tandem cyclization
approach to tetracyclic indolines. Org. Lett. 2010, 12, 1448−1451.
(20) Sanchez, I. H.; Lopez, F. J.; Soria, J. J.; Larraza, M. I.; Flores, H.
J. Total synthesis of ( )-elwesine, ( )-epielwesine, and ( )-oxocri-
nine. J. Am. Chem. Soc. 1983, 105, 7640−7643.
(21) Wu, C.; Decker, E. R.; Blok, N.; Bui, H.; You, T. J.; Wang, J.;
Bourgoyne, A. R.; Knowles, V.; Berens, K.; Holland, G. W.; Brock, T.
A.; Dixon, R. A. F. Discovery, modeling, and human pharmacokinetics
of N-(2-acetyl-4,6-dimethylphenyl)-3-(3,4-dimethylisoxazol-5-
ACKNOWLEDGMENTS
■
This work was supported by the University of Colorado, the
Colorado Bioscience Discovery Evaluation Grant, and National
Institutes of Health Institutional Training Grant GM008732
(to J.D.P).
ABBREVITIONS USED
■
MRSA, methicillin-resistant S. aureus; MSSA, methicillin-
sensitive S. aureus; PBP, penicillin binding protein; RMA,
resistance-modifying agent; CLSI, Clinical Laboratory Stand-
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Journal of Medicinal Chemistry
Article
ylsulfamoyl)thiophene-2-carboxamide (TBC3711), a second gener-
ation, ETA selective, and orally bioavailable endothelin antagonist. J.
Med. Chem. 2004, 47, 1969−1986.
(22) Clinical and Laboratory Standards Institute (CLSI). Methods for
Dilution Amntimicrobial Susceptibility Tests for Bacteria That Grow
Aerobically; Approved Standard; CLSI: Wayne, PA, 2009.
(23) Sopirala, M. M.; Mangino, J. E.; gebreyes, W. A.; Beller, B.;
Bannerman, T.; Balada-Llasat, J. M.; Pancholi, P. Synergy testing by
Etest, microdilution checkerboard, and time-kill methods for pan-drug-
resistant Acinetobacter baumannii. Antimicrob. Agents Chemother. 2010,
54, 4678−4683.
(24) Meng, H.; Kumar, K. Antimicrobial activity and protease
stability of peptides containing fluorinated amino acids. J. Am. Chem.
Soc. 2007, 129, 15615−15622.
(25) Wang, F.; Qin, L.; Pace, C. J.; Malonis, R.; Gao, J. Solubilized
gramicidin A as potential systemic antibiotics. ChemBioChem 2012, 13,
51−55.
(26) Wright, G. D. The antibiotic resistome: The nexus of chemical
and genetic diversity. Nat. Rev. Microbiol. 2007, 5, 175−186.
3817
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