Synthesis, modification and docking studies of 5-sulfonyl isatin derivatives as SARS-CoV 3C-like protease inhibitors

Article abstract of DOI:10.1016/j.bmc.2013.11.028

The Severe Acute Respiratory Syndrome (SARS) is a serious life-threatening and strikingly mortal respiratory illness caused by SARS-CoV. SARS-CoV which contains a chymotrypsin-like main protease analogous to that of the main picornavirus protease, 3CL^pro. 3CL^pro plays a pivotal role in the viral replication cycle and is a potential target for SARS inhibitor development. A series of isatin derivatives as possible SARS-CoV 3CL ^pro inhibitors was designed, synthesized, and evaluated by in vitro protease assay using fluorogenic substrate peptide, in which several showed potent inhibition against the 3CL^pro. Structure-activity relationship was analyzed, and possible binding interaction modes were proposed by molecular docking studies. Among all compounds, 8k₁ showed most potent inhibitory activity against 3CL^pro (IC₅₀ = 1.04 μM). These results indicated that these inhibitors could be potentially developed into anti-SARS drugs.

Full text of DOI:10.1016/j.bmc.2013.11.028

Accepted Manuscript
Synthesis, modification and docking studies of 5-sulfonyl isatin derivatives as
SARS-CoV 3C-like protease inhibitors
Wei Liu, He-Min Zhu, Guo-Jun Niu, En-Zhi Shi, Jie Chen, Bo Sun, Wei-Qiang
Chen, Hong-Gang Zhou, Cheng Yang
PII:
S0968-0896(13)00959-0
DOI:
http://dx.doi.org/10.1016/j.bmc.2013.11.028
BMC 11236
Reference:
Bioorganic & Medicinal Chemistry
To appear in:
Received Date:
Revised Date:
Accepted Date:
30 August 2013
12 November 2013
13 November 2013
Please cite this article as: Liu, W., Zhu, H-M., Niu, G-J., Shi, E-Z., Chen, J., Sun, B., Chen, W-Q., Zhou, H-G.,
Yang, C., Synthesis, modification and docking studies of 5-sulfonyl isatin derivatives as SARS-CoV 3C-like
protease inhibitors, Bioorganic & Medicinal Chemistry (2013), doi: http://dx.doi.org/10.1016/j.bmc.2013.11.028
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Synthesis, modification and docking studies of 5-sulfonyl isatin
derivatives as SARS-CoV 3C-like protease inhibitors
Wei Liua,*, He-Min Zhub, Guo-Jun Niud, En-Zhi Shib, Jie Chenc, Bo Sund,
Wei-Qiang Chend, Hong-Gang Zhouc, Cheng Yangc,d
aCollege of Sciences, Tianjin University of Science and Technology, Tianjin 300457,
China
bCollege of Life Sciences, NanKai University, Tianjin 300071, China
cCollege of Pharmacy, NanKai University, Tianjin 300071, China
dHigh Throughput Molecular Drug Discovery Center, Tianjin International Joint
Academy of Biotechnology and Medicine, TEDA, Tianjin 300457, China
Corresponding author: Wei Liu
E-mail addresses: liuwei2006@tust.edu.cn
Corresponding author. Tel.: +86 22 65378878
Abstract
The Severe Acute Respiratory Syndrome (SARS) is a serious life-threatening
and strikingly mortal respiratory illness caused by SARS-CoV. SARS-CoV which
contains a chymotrypsin-like main protease analogous to that of the main picornavirus
protease, 3CLpro. 3CLpro plays a pivotal role in the viral replication cycle and is a
potential target for SARS inhibitor development. A series of isatin derivatives as
possible SARS-CoV 3CLpro inhibitors was designed, synthesized, and evaluated by in
vitro protease assay using fluorogenic substrate peptide, in which several showed
1

potent inhibition against the 3CLpro. Structure–activity relationship was analyzed, and
possible binding interaction modes were proposed by molecular docking studies.
Among all compounds, 8k1 showed most potent inhibitory activity against 3CLpro
(IC50 = 1.04 µM). These results indicated that these inhibitors could be potentially
developed into anti-SARS drugs.
Keywords: SARS, inhibitor, isatin, docking studies
1. Introduction
The Severe Acute Respiratory Syndrome (SARS) is a serious life-threatening
upper respiratory tract disease with the most common symptoms of cough, high fever,
headache, rigor, myalgia, and dizziness.1 In 2003, SARS abruptly emerged and spread
widely, becoming an epidemic that seriously affected public health and the economy
of many countries.2,3 Although SARS has been controlled and no known SARS
transmission has been recorded anywhere in the world, the mutant characteristic of
the coronavirus that is the causative agent of SARS indicated the possibility of a
re-emergence.4-6 The emergence of the novel human coronavirus EMC (HCoV-EMC)
in the Middle East since April 2012 has so far led to 17 cases of human infection
(with 11 being fatal) as of 26 March 2013.7
SARS virus is a novel human coronavirus featuring the largest positive-stranded
RNA genomes known to date (27-31 kb) and is also termed SARS-CoV. CoV
encodes a chymotrypsin-like protease (3CLpro) that plays a pivotal role in the virus
replication. The cysteine protease 3CLpro is fuctionally analogous to the main
2

Picornaviridae protease 3Cpro with a catalytic dyad (Cys-145 and His-41) in the active
site.8 3CLpro cleaves the replicase polyprotein at 11 conserved sites with canonical
Leu-Gln (Ser, Ala, Gly) sequences, in which the P1 position has a well-conserved
Gln residue and the P2 position has a hydrophobic amino acid residue.9,10 Given the
essential role in viral processing of SARS-CoV 3CLpro, it is considered as an
attractive target for anti-SARS and other coronavirus infections.
A large number of peptidomimetic and small-molecule inhibitors of 3CLpro have
been reported to date, including peptideomimetic,11-21 stilbene derivatives,22
hydroxyferroquine derivatives,23 TG-0205221,24 natural products,25-28 ketones,29, 30
glycyrrhizic acid,31 pyrimidines,32 α,ß-unsaturated esters,33 ML188,34 pyrazolones,35
nucleoside analogs,36,37 and isatin derivatives.38,39 Although so many candidate
anti-SARS CoV agents have been identified, no effective therapeutic drug and
vaccine have been developed so far.
Figure 1. 5-Bromoisatin soaked into a crystal of 3CLpro (2.8 Å)
3

High-throughput screening revealed that 5-bromoisatin was a potent inhibitor, and
then 5-bromoisatin was also soaked into a crystal of 3CLpro recently obtained in our
laboratory (Fig. 1). Although this complex has not been deposited in the protein data
bank because of the poor structural quality, this fact provided us with an important
clue that isatin derivatives can have inhibitory activity against 3CLpro. Previously,
Chen and Zhou et al.38,39 reported a new class of potent, small-molecule isatin-based
3CLpro inhibitors (Fig. 2). They concluded that the C-5 position favors a carboxamide
group and the N-1 position favors large hydrophobic substituents. In this paper, we
investigated a replacement of the carboxamide group using a series of substituted
sulfonamide groups in isatin. We believe that this modification can improve inhibitory
activity against SARS CoV 3CLpro. We also carried out molecular docking studies to
obtain the potential binding mode of these inhibitors.
Figure 2. Structures of isatins I and II that reportedly demonstrate in vitro SARS-CoV 3CLpro
inhibition.
2. Results and Discussion
2.1 Chemistry
4

Scheme 1. Synthesis of compounds 3g and 3i
Compounds 3a-f, 3h, and 3j were obtained from commercial suppliers. The
synthesis of isatin derivatives 3g and 3i is summarized in Scheme 1. Intermediates 2g
and 2i were prepared by the Sandmeyer reaction of substituted anilines with
hydroxylamine
hydrochloride
and
chloral
hydrate.
The
resulting
hydroxyiminoacetanilide intermediates 2g and 2i were cyclized by heating in
concentrated sulfuric acid to give the corresponding isatin derivatives 3g and 3i,
respectively.40
Scheme 2. Synthesis of compounds 7 and 8
A series of compounds 8 was prepared from isatin following literature
methods41,42 (Scheme 2). In a typical procedure, isatin was sulfonated at the 5-position
in the presence of chlorosulfonic acid. However, in contrast to previously published
5

results, both 5-sulfonated gem-dichloroisatin 4 and 5-sulfonated isatin 5 were isolated,
and the yield ratio was 9:1. Moreover, no desired sulfonyl chloride product was
obtained. Interestingly, both 4 and 5 can react with secondary amines, respectively.
Especially, 5 can directly produce compound 7 in high yield. In this paper, the
mixture of compounds 4 and 5 was not isolated and was applied to synthesize target
compounds 7 and 8, and the gem-dichloro moiety of intermediate 6 was subjected to
acidic hydrolysis to afford 7. Alkylation of 7 was achieved in the presence of various
bromides or iodides and NaH in DMF. Both analytical and spectral data of all target
compounds 7 and 8 were accordant with their structures.
2.2 Biological activity
A series of compounds 3 substituted at the benzene ring of isatin was initially
screened against SARS CoV 3CLpro in vitro, and results are summarized in Table 1.
SARS CoV 3CLpro was found to be sensitive to the substituent position. Inhibitory
activity results showed that compounds 3a-f and 3h substituted at the 5-position were
superior to those of compounds 3i and 3j substituted at other positions. This result
indicated that modification at the 5-position of the isatin ring was suitable and much
more effective in increasing inhibitory potency. The replacement of bromine 3a at the
5-position by iodine 3b, chlorine 3c, and fluorine 3d did not increase inhibitory
activity. Table 1 shows that most of compounds containing the oxy substituent 3e-h
displayed high inhibitory activity, except 3g. Results revealed that the substituent
6

containing the oxy group at the 5-position was important in improving inhibitory
activity.
Table 1. Inhibitory activities of compounds 3 against SARS CoV 3CLpro
Compound
R1
R
Inhibition ratio (1 mM)
Br
I
H
H
H
H
H
H
H
H
--
90.54%
86.73%
84.17%
82.55%
93.96%
95.32%
44.77%
95.37%
79.36%
68.44%
3a
3b
3c
3d
3e
3f
Cl
F
NO2
OCH3
COOH
COCH3
--
3g
3h
3i
H
Br
3j
Considering the inhibitory tendency in Table 1, 5-(piperazin-1-ylsulfonyl)isatin
derivatives 7a-h were prepared and evaluated by inhibition assays, and the results are
shown in Table 2. Compared with 3, compound 7a exhibited a higher inhibition ratio
(98.64%), with IC50 = 76.74 µM. Although compounds 7b and 7c were less active
than 7a, 7d-h exhibited the increased inhibitory potency. Both one carbon (7d, IC50 =
31.71 µM; 7e, IC50 = 32.08 µM) and two carbons (7f, IC50 = 34.91 µM) between
aromatic ring and piperazine showed a similar profile, which was an approximately
twofold higher potency than 7a. Compound 7h containing more hydrophilic moiety
(pyridinyl) instead of the phenyl ring slightly increased activity (IC50 = 51.33 µM)
compared with compounds 7b and 7c. In particular, the substituent with flexibility
7

increased potency (7d-g, IC50 < 35 µM) compared with 7b-c. These results suggested
that the steric effect in isatin scaffold was crucial to ensuring inhibitory potency.
Table 2. Inhibitory activities of compounds 7a-m against SARS CoV 3CLpro
Compound
R2
IC50 (µM)
76.74 2.99
7a
>100
>100
7b
7c
7d
31.71 1.41
32.08 2.83
7e
34.91 9.48
10.07 0.59
51.33 2.47
7f
7g
7h
8

4.45 0.13
12.66 0.28
1.18 0.11
2.25 0.14
7i
7j
7k
7l
4.30 0.07
7m
Replacement of the piperazinyl moiety by other simple cyclic secondary amines
was also examined (Table 2) to determine the most suitable substituent. Unexpectedly,
7i-m induced a more apparent improvement in inhibitory potency than bicyclic
substituents 7b-h, and 5-(piperidin-1-ylsulfonyl)isatin derivatives 7i and 7k-m
showed better potency with IC50 < 5 µM. Among them, 4-methylpiperidinyl (7k, IC50
= 1.18 µM) and 2-methylpiperidinyl (7l, IC50 = 2.25 µM) were the optimal
substituents for enzyme inhibition, which enhanced potency by about 80- and 40-fold
compared with 7a, respectively.
After determining the influence of the substituent at the 5-position, we
synthesized and examined a series of N-substituted isatin derivatives 8 to determine
whether the inhibitory potency against SARS CoV 3CLpro can be enhanced by
modified isatin derivatives at the N-1 position. As shown in Table 3, introduction of
methyl, benzyl, and β-naphthyl methyl into the N-1 position showed significant
9

activity variation. Most remarkably, methyl at the N-1 position resulted in a 1- to
10-fold enhancement in the inhibitory potency compared with the parent compounds
7 in Table 2, and these compounds displayed higher potency than the ones with
benzyl or β-naphthyl methyl. However, 7k (IC50 = 1.18 µM) was not sensitive to
methyl (8k1, IC50 = 1.04 µM) or benzyl (8k2, IC50 = 1.69 µM), which exhibited high
inhibitory potency. Explaining such similar activity tendencies was difficult, so
docking studies were conducted.
Table 3. Inhibitory activities of compounds 8 against SARS CoV 3CLpro
Compound
R2
R3
IC50 (µM)
CH3
11.83 1.87
8a1
PhCH2
β-C10H7CH2
PhCH2
67.20 8.50
82.91 12.91
ND
8a2
8a3
8b2
8b3
ND
β-C10H7CH2
10

PhCH2
β-C10H7CH2
CH3
ND
ND
8d2
8d3
8f1
8f2
8f3
8h1
8h2
8h3
8i2
13.86 1.546
PhCH2
ND
ND
β-C10H7CH2
CH3
5.52 0.33
PhCH2
ND
ND
β-C10H7CH2
PhCH2
14.00 2.472
ND
8i3
β-C10H7CH2
11

CH3
PhCH2
9.91 0.79
13.86 2.96
39.87 0.62
1.04 0.01
1.69 0.01
17.82 0.72
2.82 0.17
4.70 0.12
ND
8j1
8j2
8j3
β-C10H7CH2
CH3
8k1
8k2
8k3
8m1
8m2
8m3
PhCH2
β-C10H7CH2
CH3
PhCH2
β-C10H7CH2
ND: not done because of quenching rate > 20 %.
2.3 Docking Studies
12

Figure 3. Binding interactions of 8k1 and 8k2 in the protein structure 1UK4, respectively.
Hydrogen bonds are shown as green lines and hydrophobic contacts are shown as radial
hemispheres.
Figure 4. (left) Three molecules (7k, gray; 8k1, cyan; and 8k2, green) are bound in the SARS
3CLpro active site. Four parts of the active site are shown. (right) Surface representation of SARS
3CLpro (PDB ID 1UK4) with three inhibitors, 7k (gray), 8k1 (cyan), and 8k2(green).
To predict the binding mode of isatin 5-sulfonylamide onto the active site of SARS
CoV 3CLpro (PDB code 1UK4) using Glide 5.5 (Glide model in Schrodinger
software), compounds 7k, 8k1, and 8k2 were docked into the active site. As shown in
Figure 3, compound 8k1 was hydrogen bonded in Gly143 and Cys145 of protease,
13

and 8k2 generated hydrogen bonds with Gly143, Ser144, and Asn142. Notably, both
carbonyl group at the 2-position and nitrogen atom at the 1-position of isatin are
important in the formation of hydrogen bonds. Meanwhile, the modeling shown in
Figure 4 revealed that the isatin scaffold was docked at the S1’ site, and the side chain
R2 and R3 were located at the S2 and S1 sites of SARS CoV 3CLpro, respectively. The
model of compounds and SARS-CoV 3CLpro presented here differed from previously
reported 5-carboxamide isatin derivatives.39 The orientation of the isatin core was
flipped here in Fig. 4. The substitutions at the 5-position enabled the compounds 8k1
and 8k2 to fit the S2 hydrophobic site in both docking results. Furthermore, the simple
six-membered ring sulfonyl group of isatin at the 5-position well fitted S2, as
demonstrated in the potent inhibition of 7a and 7i-m. However, the 5-sulfonyl isatin
derivatives 7b-h modified by rigid bicyclic substituents at the 5-position did not fit
the limited space of S2, which led to diminished inhibitory activity. Interestingly,
increasing the length of substitution enabled compounds containing the flexible group
7d-g to extend into the S3 site, which has not been mentioned in previous references.
These docking experiments supported the observation in the enzymatic assay that the
potency of these derivatives followed the order 7d (31.71 µM) > 7a (76.74 µM) > 7b
(>100 µM). Regarding the substituent at the N-1 position, the 5-carboxamide
group39 was replaced by N-1 substitution here and the methyl and benzyl substitutions
more or less accommodated the hydrophobic characteristics at the S1 site.
In
addition, 8k1 molecule (total score = 8.70) was predicted to show the analogous
14

binding affinity relative to 8k2 (total score = 8.58), which was consistent with the
experimental results. Based on the findings above, we believe that the activity of the
title compounds can be improved by modifying with the simple six-membered ring at
the 5-position and substitution at the N-1 position with a methyl group, which can
lead to a better combination of compounds with the protein pocket.
3. Conclusion
5-Bromoisatin 3a selected by high-throughput screening and socking experiments,
was proved to have potent inhibitory activity against SARS 3CLpro in vitro.
Optimization of 5-sulfonyl isatin derivatives resulted in the discovery of compound
8k1, with the most powerful potency (IC50 = 1.04 µM). The results of the current
study suggested that 5-sulfonyl isatin derivatives had similar inhibitory activities to
the reported 5-carbonyl isatins. Meanwhile, the computer model of the associated
complex between the title compounds and protease rationalized their inhibitory
activities. Apparently, 5-sulfonyl isatin modified by a simple six-membered ring or a
bulky substituent with sufficient flexibility at the 5-position coupled with methyl at
the N-1 position could dramatically promote inhibitory activity. In addition, similar
orientations of the isatin core were found in both docking and socking studies. This
result could serve as an important basis for more structural optimizations.
4. Experimental
4.1. Chemistry
4.1.1. General. All reactions were carried out under N2 atmosphere unless otherwise
noted. All commercial reagents were of the highest purity available. Tetrahydrofuran
15

(THF) was distilled from sodium and benzophenone. Analytical TLC was performed
with SHANGHAI SANPONT GF254. Column chromatography was carried out on
SHANGHAI SANPONT Gel (200–300 mesh). NMR spectra were recorded on a
Bruker AM-400 or DMX-600. All NMR spectra were recorded in CDCl3 or DMSO at
room temperature (20 °C). Chemical shifts for 1H and 13C spectra were quoted in ppm
downfield from TMS. Coupling constants are referred to as J values. ESI mass spectra
were obtained using a Bruker ESQUIRELCTM ESI ion trap spectrometer. FT-IR
spectra were determined at room temperature (20 °C) within 4000–400 cm-1 with a
PerkinElmer spectrum 65 FT-IR spectrometer using KBr pellets. Melting points were
determined using an SGW-X4B digital melting point apparatus. Elemental analysis of
carbon, hydrogen and nitrogen were obtained with an Elementar Vario MICRO cube
Elemental Analyser.
4.1.2. General Procedure for the Synthesis of Compounds 3g and 3i40. Chloral
hydrate (14.7 g, 88.8 mmol) was added to 500 ml of water with dissolved sodium
sulfate (84 g, 0.59 mol). When the temperature reached 40 °C, the appropriate aniline
(74.0 mmol) in 25 ml of 2 M aqueous hydrochloric acid was added dropwise. The
reaction mixture was stirred for 1h. and the suspension of hydroxylamine
hydrochloride (18.5 g, 0.27 mol) was rapidly added to the reaction mixture. The
mixture was then heated at 90 °C for 5h with stirring. After cooling to room
temperature, the corresponding hydroxyiminoacetanilide 2g (or 2i) was collected by
filtration, washed with water, and dried in a vacuum. Under nitrogen atmosphere, one
16

gram of the intermediate 2g (or 2i) was added in small portions with stirring to 30 ml
of concentrated sulfuric acid that had been preheated and maintained at 50 °C. After
all intermediates had been added, the dark-colored solution was heated at 55 °C for an
additional 30 min, cooled to room temperature, poured onto 225 ml of crushed ice,
and allowed to stand for 30 min. The precipitate was collected by filtration, washed
with water three times, and dried under vacuum to yield the product 3g (or 3i).
1
4.1.2.1. 5-Carboxy-1H-indole-2,3-dione (3g): H-NMR (400 MHz, DMSO-d6) δ:
13.01 (s, 1H), 11.34 (s, 1H), 8.12 (dd, J = 8.2, 1.7 Hz, 1H), 7.88 (d, J = 1.3 Hz, 1H),
6.97 (d, J = 8.2 Hz, 1H). ESI-MS: m/z 192.33 ([M+H+]).
1
4.1.2.2. 1,5,6,7-Tetrahydro-cyclopent[f]indole-2,3-dione (3i): H-NMR (400 MHz,
CDCl3) δ: 8.40 (s, 1H), 7.44 (s, 1H), 6.80 (s, 1H), 2.95 (t, J = 7.6 Hz, 2H), 2.89 (t, J =
7.6 Hz, 2H), 2.13 (t, J = 7.6 Hz, 2H). ESI-MS: m/z 188.12 ([M+H+]).
4.1.3. Synthesis of Compounds 4 and 5. Under nitrogen and ice bath, 20.0 ml (302
mmol) of chlorosulfonic acid was added dropwise to 3.6 g (24.5 mmol) isatin. Then,
the mixture was heated to 70 °C for 3 h. The mixture was cooled down to room
temperature and carefully poured onto 100 g of ice. The resulting yellow solid was
filtered, washed with cold water. and dissolved in the ethyl acetate. After drying over
Na2SO4, the mixture was purified by column chromatography (petroleum ether and
ethylacetate), and compounds 4 (3.8 g) and 5 (410 mg) were obtained. Interestingly,
either 4 or 5 can react with secondary amines, and 5 can directly produce the
17

compound 7 in high yield. The resulting precipitate was used in the next step without
separation.
1
4.1.3.1. 3,3-Dichloro-2-oxo-indoline-5-sulfonic acid (4): Pale yellow powder. H
NMR (400 MHz, DMSO-d6) δ 14.42 (s, 1H), 11.50 (s, 1H), 7.77 (s, 1H), 7.66 (d, J =
8.4 Hz, 1H), 6.96 (d, J = 8.4 Hz, 1H). 13C NMR (100 MHz, DMSO-d6) δ 169.6, 144.4,
139.7, 130.3, 128.5, 122.4, 111.1, 75.4. ESI-MS: m/z 279.74 ([M-H-]).
4.1.3.2. 2,3-Dioxo-indoline-5-sulfonic acid (5): Yellow powder. 1H NMR (400 MHz,
DMSO-d6) δ14.49 (s, 1H), 11.14 (s, 1H), 7.81 (d, J = 8.0 Hz, 1H), 7.59 (s, 1H), 6.89
(d, J = 8.0 Hz, 1H). 13C NMR (100 MHz, DMSO-d6) δ 184.7, 160.0, 150.9, 143.8,
135.9, 121.8, 117.4, 111.9. ESI-MS: m/z 225.87 ([M-H-]).
4.1.4. General Procedure for the Synthesis of Compounds 7a-m. Under nitrogen
atmosphere, mixture of 4 and 5 (2.0 mmol) was dissolved in 6 ml of dried THF at 0
°C. Then, a solution of the secondary amine (2.2 mmol) and diisopropylethylamine
(3.0 mmol) in 1 ml of THF was slowly added. After stirring the reaction mixture at
room temperature overninght, solvents were removed and a brown oil was obtained.
The crude product was added to 15 ml of 1:1(v/v) acetic acid–water solution. The
mixture was heated at 90 °C overnight. About 11 g of NaHCO3 was carefully added
to the mixture after cooling down. The product was extracted by ethylacetate, washed
with water, and dried over MgSO4. Target compound 7 was purified by column
chromatography using CH2Cl2 and CH3OH.
4.1.4.1. 5-[(4-Methylpiperazin-1-yl)sulfonyl]-1H-indole-2,3-dione (7a). Compound
7a was prepared according to General Procedure above using 1-methylpiperazine.
18

Pale yellow powder. Yield 57%. m.p. 173.5-174.8 °C. 1H NMR (400 MHz,
DMSO-d6) δ 11.47 (s, 1H), 7.90 (dd, J = 8.4, 2.0 Hz, 1H), 7.68 (d, J = 2.0 Hz, 1H),
7.12 (d, J = 8.4 Hz, 1H), 2.90 (s, 4H), 2.36 (t, J = 4.4 Hz, 4H), 2.14 (s, 3H). 13C NMR
(100 MHz, DMSO-d6) δ 183.3, 159.9, 154.3, 137.5, 129.2, 123.9, 118.7, 113.2, 53.6,
45.8, 45.2. IR (KBr, cm-1): 3370, 3090, 2940, 2808, 1747, 1618, 1467, 1356, 1177,
946, 735. ESI-MS: m/z 310.16 ([M+H+]), 308.20 ([M-H+]). Anal. Calcd for
C13H15N3O4S: C, 50.47; H, 4.89; N, 13.58. Found: C, 50.27; H, 4.78; N, 13.44.
4.1.4.2. 5-{[4-(4-Fluorophenyl)piperazinyl-1-yl]sulfonyl}-1H-indole-2,3-dione (7b).
Compound 7b was prepared according to General Procedure above by using
1-(4-fluorophenyl)piperazine. Pale yellow powder. Yield 36%. m.p. 208.7-210.3 °C.
1H NMR (400 MHz, DMSO-d6) δ 11.49 (s, 1H), 7.95 (dd, J = 8.4, 2.0 Hz, 1H), 7.72
(d, J = 1.6 Hz, 1H), 7.13 (d, J = 8.0 Hz, 1H), 7.04 (t, J = 8.4 Hz, 2H), 6.94-6.91 (m,
2H), 3.15 (t, J = 4.0 Hz, 4H), 3.03 (t, J = 4.0 Hz, 4H). 13C NMR (150 MHz, DMSO-d6)
δ 183.3, 160.0, 156.9 (d, J = 229 Hz), 154.4, 147.7, 137.6, 128.9, 123.9, 118.8, 118.6
(d, J = 7.5 Hz), 115.8 (d, J = 21 Hz), 113.3, 49.1, 46.3. IR (KBr, cm-1): 3299, 3237,
2919, 1755, 1614, 1340, 1245, 1155, 952, 819. ESI-MS: m/z 390.24 ([M+H+]). Anal.
Calcd for C18H16N3O4S: C, 55.52; H, 4.14; N, 10.79. Found: C, 55.34; H, 4.27; N,
10.75.
4.1.4.3.
5-{[4-(3-Trifluoromethylphenyl)piperazinyl-1-yl]sulfonyl}-1H-indole-2,3-dione
(7c). Compound 7c was prepared according to General Procedure above by using
19

1-[3-(trifluoromethyl)phenyl]piperazine. Pale yellow powder. Yield 41%. m.p.
213.6-215.0 °C. 1H NMR (400 MHz, DMSO-d6) δ 11.47 (s, 1H), 7.95 (dd, J = 8.0, 2.0
Hz, 1H), 7.72 (d, J = 2.0 Hz, 1H), 7.41 (t, J = 8.0 Hz, 1H), 7.20-7.08 (m, 4H), 3.34 (t,
13
J = 4.4 Hz, 4H), 3.05 (t, J = 4.4 Hz, 4H). C NMR (100 MHz, DMSO-d6) δ 183.3,
159.9, 154.4, 151.0, 137.6, 130.5, 130.4(q, J = 31 Hz), 128.9, 124.8(q, J = 271 Hz),
123.9, 119.9, 118.8, 115.9(d, J = 4 Hz), 113.3, 111.2 (d, J = 4 Hz), 47.7, 46.1. IR
(KBr, cm-1): 3298, 3244, 2834, 1755, 1612, 1453, 1342, 1154, 953. ESI-MS: m/z
440.19 ([M+H+]), 438.22 ([M-H+]). Anal. Calcd for C19H16N3O4S: C, 51.93; H,
3.67; N, 9.56. Found: C, 51.87; H, 3.61; N, 9.49.
4.1.4.4. 5-{[4-(3-Chlorobenzyl)piperazinyl-1-yl]sulfonyl}-1H-indole-2,3-dione (7d).
Compound 7d was prepared according to General Procedure above by using
1-(3-chlorobenzyl)piperazine. Pale yellow powder. Yield 47%. m.p. 150.8-152.1 °C.
1H NMR (400 MHz, DMSO-d6) δ 11.48 (s, 1H), 7.90 (dd, J = 8.4, 1.6 Hz, 1H), 7.67
(s, 1H), 7.39 (m, 2H), 7.27 (m, 2H), 7.12 (d, J = 8.4 Hz, 1H), 3.56 (s, 2H), 2.91 (s,
4H), 2.50 (t, J = 9.2 Hz, 4H) (determination in CD3OD). 13C NMR (100 MHz,
DMSO-d6) δ 183.3, 159.9, 154.3, 137.5, 135.6, 133.7, 131.2, 129.7, 129.2, 128.9,
127.5, 123.9, 118.7, 113.2, 58.5, 51.9, 46.5. IR (KBr, cm-1): 3363, 3067, 2850, 1755,
1614, 1456, 1288, 1156, 942, 753. ESI-MS: m/z 440.19 ([M+H+]). Anal. Calcd for
C19H18ClN3O4S: C, 54.35; H, 4.32; N, 10.01. Found: C, 54.02; H, 4.23; N, 9.77.
4.1.4.5.
5-{[4-(3,4,5-Trimethoxybenzyl)piperazinyl-1-yl]sulfonyl}-1H-indole-2,3-dione
20

(7e). Compound 7e was prepared according to General Procedure above by using
1-(3,4,5-trimethoxybenzyl)piperazine dihydrochloride. To neutralize hydrochloric
acid
from
1-(3,4,5-trimethoxybenzyl)piperazine
dihydrochloride,
diisopropylethylamine (7.4 mmol) was added in the General Procedure for the
1
synthesis of Compound 7e. Pale yellow powder. Yield 40%. m.p. 192.2-193.9 °C. H
NMR (400 MHz, DMSO-d6) δ 11.46 (s, 1H), 7.89 (dd, J = 8.4, 2.0 Hz, 1H), 7.66 (d, J
= 2.0 Hz, 1H), 7.11 (d, J = 8.4 Hz, 1H), 6.88 (d, J = 8.4 Hz, 1H), 6.71 (d, J = 8.4 Hz,
1H), 3.75 (s, 3H), 3.71 (s, 6H), 3.38 (s, 2H), 2.89 (s, 4H), 2.43 (s, 4H). 13C NMR
(100 MHz, DMSO-d6) δ 183.4, 159.9, 154.3, 153.1, 152.4, 142.3, 137.5, 129.3, 125.1,
123.8, 123.6, 118.7, 113.2, 108.1, 61.4, 60.7, 56.3, 55.7, 51.9, 46.5. IR (KBr, cm-1):
3080, 2942, 2834, 1744, 1618, 1466, 1356, 1272, 1176, 1100, 944, 745. ESI-MS: m/z
476.27 ([M+H+]). Anal. Calcd for C22H25N3O7S: C, 55.57; H, 5.30; N, 8.84.
Found: C, 55.44; H, 5.21; N, 9.02.
4.1.4.6.
5-[(4-Phenylethyl-piperazin-1-yl)sulfonyl]-1H-indole-2,3-dione
(7f).
Compound 7f was prepared according to General Procedure above by using
1
1-phenylethylpiperazine. Pale yellow powder. Yield 43%. m.p. 220.5-222.3 °C. H
NMR (400 MHz, (CD3)2CO) δ 8.00 (dd, J = 8.4, 1.6 Hz, 1H), 7.83 (d, J = 1.6 Hz,
13
1H), 7.29-7.13 (m, 6H), 3.02 (s, 4H), 2.74 (t, J = 8.4 Hz, 2H), 2.63-2.57 (m, 6H). C
NMR (100 MHz, (CD3)2CO) δ 182.9, 159.5, 153.8, 140.1, 137.0, 128.6, 128.5, 128.2,
125.9, 123.4, 118.3, 112.7, 58.9, 51.5, 45.9, 32.5. IR (KBr, cm-1): 3025, 2835, 1743,
21

1616, 1453, 1356, 1177, 952, 735. ESI-MS: m/z 400.10 ([M+H+]). Anal. Calcd for
C20H21N3O4S: C, 60.13; H, 5.30; N, 10.52. Found: C, 60.27; H, 5.34; N, 10.47.
4.1.4.7.
5-[4-(2-Furoyl)piperazin-1-yl-sulfonyl]-1H-indole-2,3-dione
(7g).
Compound 7g was prepared according to General Procedure above by using
1
1-(2-furoyl)piperazine. Pale yellow powder. Yield 30%. m.p. 261.3-263.1 °C. H
NMR (400 MHz, DMSO-d6) δ 11.47 (s, 1H), 7.91 (dd, J = 8.4, 2.0 Hz, 1H), 7.82 (s,
1H), 7.69 (d, J = 1.6 Hz, 1H), 7.11 (d, J = 8.4 Hz, 1H), 6.98 (d, J = 3.2 Hz, 1H), 6.60
(q, J = 1.6 Hz, 1H), 3.75 (s, 4H), 2.98 (t, J = 4.8 Hz, 4H). 13C NMR (100 MHz,
DMSO-d6) δ 183.4, 159.9, 158.7, 154.4, 147.0, 145.5, 137.5, 123.9, 118.8, 116.6,
113.3, 111.9, 100, 57.5, 46.5. IR (KBr, cm-1): 3121, 1755, 1619, 1483, 1351, 1153,
945, 737. ESI-MS: m/z 390.12 ([M+H+]). Anal. Calcd for C17H15N3O6S: C, 52.44;
H, 3.88; N, 10.79. Found: C, 52.29; H, 3.79; N, 10.66.
4.1.4.8. 5-{[4-(Pyridin-2-yl)piperazin-1-yl]sulfonyl}-1H-indole-2,3-dione (7h).
Compound 7h was prepared according to General Procedure above by using
1
1-(2-pyridyl)piperazine. Dark yellow powder. Yield 36%. m.p. 222.1-223.9 °C. H
NMR (400 MHz, DMSO-d6) δ 11.46 (s, 1H), 8.07 (dd, J = 4.8, 1.6 Hz, 1H), 7.93 (dd,
J = 8.0, 2.0 Hz, 1H), 7.70 (d, J = 2.0 Hz, 1H), 7.51 (td, J = 8.4, 2.0 Hz, 1H), 7.10 (d, J
= 8.0 Hz, 1H), 6.81 (d, J = 8.4 Hz, 1H), 6.63 (dd, J = 6.8, 4.8 Hz, 1H), 3.60 (t, J = 4.8
Hz, 4H), 2.98 (t, J = 4.8 Hz, 4H). 13C NMR (100 MHz, DMSO-d6) δ 183.3, 159.9,
158.7, 154.3, 148.0, 138.2, 137.5, 129.1, 123.9, 118.8, 114.0, 113.3, 107.9, 46.0, 44.4.
IR (KBr, cm-1): 2857, 1755, 1618, 1438, 1154, 949, 736. ESI-MS: m/z 373.29
22

([M+H+]). Anal. Calcd for C17H16N4O4S: C, 54.83; H, 4.33; N, 15.04. Found: C,
55.01; H, 4.21; N, 14.89.
4.1.4.9. 5-[(Piperidin-1-yl)sulfonyl]-1H-indole-2,3-dione (7i). Compound 7i was
prepared according to General Procedure above by using piperidine. Yellow powder.
1
Yield 51%. m.p. 199.9-200.8 °C. H NMR (400 MHz, DMSO-d6) δ 11.46 (s, 1H),
7.91 (dd, J = 8.4, 1.6 Hz, 1H), 7.67 (d, J = 1.2 Hz, 1H), 7.11 (d, J = 8.0 Hz, 1H), 2.89
(t, J = 5.2 Hz, 4H), 1.55 (m, 4H), 1.36 (m, 2H). 13C NMR (100 MHz, DMSO-d6) δ
183.4, 159.9, 154.1, 137.4, 129.9, 123.7, 118.6, 113.2, 47.0, 25.1, 23.3. IR (KBr,
cm-1): 3298, 2944, 2863, 1746, 1618, 1471, 1334, 1176, 934, 731. ESI-MS: m/z
295.01 ([M+H+]). Anal. Calcd for C13H14N2O4S: C, 53.05; H, 4.79; N, 9.52.
Found: C, 52.93; H, 4.61; N, 9.55.
4.1.4.10. 5-(Morpholinosulfonyl)-1H-indole-2,3-dione (7j). Compound 7j was
prepared according to General Procedure above by using morpholine. Pale yellow
powder. Yield 59%. m.p. 239.0-240.8 °C. 1H NMR (400 MHz, DMSO-d6) δ 11.49 (s,
1H), 7.91 (dd, J = 8.0, 1.6 Hz, 1H), 7.69 (s, 1H), 7.13 (d, J = 8.0 Hz, 1H), 3.64 (t, J =
4.4 Hz, 4H), 2.88 (t, J = 4.4 Hz, 4H). 13C NMR (100 MHz, DMSO-d6) δ 183.3, 156.0,
154.4, 137.6, 128.7, 123.9, 118.8, 113.3, 65.7, 46.3. IR (KBr, cm-1): 3315, 2916,
2855, 1757, 1615, 1470, 1348, 1160, 943, 737. ESI-MS: m/z 295.15 ([M-H+]). Anal.
Calcd for C12H12N2O5S: C, 48.64; H, 4.08; N, 9.45. Found: C, 48.51; H, 3.96; N,
9.22.
23

4.1.4.11.
5-[(4-Methylpiperidin-1-yl)sulfonyl]-1H-indole-2,3-dione
(7k).
Compound 7k was prepared according to General Procedure above by using
1
1-methylpiperidine. Pale yellow powder. Yield 46%. m.p. 237.3-239.0 °C. H NMR
(400 MHz, DMSO-d6) δ 11.45 (s, 1H), 7.90 (dd, J = 8.4, 2.0 Hz, 1H), 7.68 (d, J = 2.0
Hz, 1H), 7.10 (d, J = 8.4 Hz, 1H), 3.59 (d, J = 11.6 Hz, 2H), 2.22 (dd, J = 12.0, 10.0
Hz, 2H), 1.65 (d, J = 10.8 Hz, 2H), 1.29 (m, 1H), 1.13 (m, 2H), 0.84 (d, J = 10.8 Hz,
3H). 13C NMR (100 MHz, DMSO-d6) δ 183.4, 159.9, 154.1, 137.4, 130.0, 123.7,
118.6, 113.2, 46.2, 33.3, 29.8, 21.7. IR (KBr, cm-1): 3228, 2922, 1725, 1610, 1338,
1159, 919, 619. ESI-MS: m/z 309.06 ([M+H+]). Anal. Calcd for C14H16N2O4S: C,
54.53; H, 5.23; N, 9.08. Found: C, 54.64; H, 5.10; N, 9.01.
4.1.4.12.
5-[(2-Methylpiperidin-1-yl)sulfonyl]-1H-indole-2,3-dione
(7l).
Compound 7l was prepared according to General Procedure above by using
1
2-methylpiperidine. Pale yellow powder. Yield 37%. m.p. 235.1-237.0 °C. H NMR
(400 MHz, DMSO-d6) δ 11.41 (s, 1H), 7.98 (dd, J = 8.4, 2.0 Hz, 1H), 7.74 (d, J = 1.2
Hz, 1H), 7.07 (d, J = 8.4 Hz, 1H), 4.10 (m, 1H), 3.59 (d, J = 10.4 Hz, 1H), 2.96 (td, J
= 12.8, 2.0 Hz, 1H), 1.55-1.43 (m, 5H), 1.21 (m, 1H), 1.03 (d, J = 7.2 Hz, 3H). 13C
NMR (100 MHz, DMSO-d6) δ 183.5, 156.0, 153.7, 136.6, 135.4, 122.9, 118.6, 113.2,
48.7, 30.3, 25.2, 18.1, 15.7. IR (KBr, cm-1): 3195, 2949, 1747, 1614, 1465, 1332,
1134, 993, 719. ESI-MS: m/z 309.01 ([M+H+]). Anal. Calcd for C14H16N2O4S: C,
54.53; H, 5.23; N, 9.08. Found: C, 54.51; H, 5.03; N, 8.88.
24

4.1.4.13. 5-[(3,5-Dimethylpiperidin-1-yl)sulfonyl]-1H-indole-2,3-dione
(7m).
Compound 7m was prepared according to General Procedure above by using
1
3,5-dimethylpiperidine. Yellow powder. Yield 47%. m.p. 221.1-222.5 °C. H NMR
(400 MHz, CDCl3) δ 8.26 (s, 1H), 7.99 (m, 2H), 7.09 (d, J = 8.4 Hz, 1H), 3.72 (d, J =
6.8 Hz, 2H), 1.75 (m, 4H), 1.25 (m, 2H), 0.87 (d, J = 6.0 Hz, 6H). 13C NMR (100
MHz, DMSO-d6) δ 183.5, 159.9, 154.1, 137.4, 130.1, 123.6, 118.6, 113.2, 52.7, 41.1,
30.9, 19.2. IR (KBr, cm-1): 3292, 2956, 1762, 1617, 1341, 1150, 796. ESI-MS: m/z
323.11 ([M+H+]). Anal. Calcd for C15H18N2O4S: C, 55.88; H, 5.63; N, 8.69.
Found: C, 55.69; H, 5.47; N, 8.77.
4.1.5. General Procedure for the Synthesis of Compounds 8a1-m3.
At 0 °C, 10 mg of NaH (60%, 0.25 mmol) was added to a solution of the
corresponding 7 (0.25 mmol) in 3 ml of DMF. The mixture was stirred for 15 min,
and then 0.5 mmol of R3X was added. The mixture was stirred for 1.5 h at room
temperature, added with 30 ml of water, extracted by 50 ml of ethyl acetate, washed
with 30 ml of saturated NaCl and dried over Na2SO4. After solvent removal, the crude
product was purified by column chromatography with CH2Cl2 to afford product 8.
4.1.5.1. 1-Methyl-5-[(4-methylpiperazin-1-yl)sulfonyl]-1H-indole-2,3-dione (8a1).
Compound 8a1 was prepared according to General Procedure above by using
compound 7a and iodomethane. Yellow powder. Yield 90%. m.p. 207.8-209.1 °C. 1H
NMR (400 MHz, CDCl3) δ 8.01 (dd, J = 8.4, 1.6 Hz, 1H), 7.96 (d, J = 1.6 Hz, 1H),
7.04 (d, J = 8.4 Hz, 1H), 3.32 (s, 3H), 3.07 (s, 4H), 2.50 (t, J = 5.6 Hz, 4H), 2.28 (s,
25

3H). 13C NMR (100 MHz, CDCl3) δ 181.7, 157.7, 154.3, 137.8, 131.7, 124.8,
117.3,110.2, 53.9, 45.9, 45.7, 26.7. IR (KBr, cm-1): 2926, 2798, 1752, 1610, 1342,
1285, 1153, 960, 748. ESI-MS: m/z 324.33 ([M+H+]). Anal. Calcd for
C14H17N3O4S: C, 52.00; H, 5.30; N, 12.99. Found: C, 51.84; H, 5.15; N, 12.87.
4.1.5.2. 1-Benzyl-5-[(4-methylpiperazin-1-yl)sulfonyl]-1H-indole-2,3-dione (8a2).
Compound 8a2 was prepared according to General Procedure above by using
compound 7a and benzyl bromide. Yellow powder. Yield 91%. m.p. 179.1-181.8 °C.
1H NMR (400 MHz, CDCl3) δ 7.97 (d, J = 1.6 Hz, 1H), 7.87 (dd, J = 8.4, 1.6 Hz, 1H),
7.40-7.31 (m, 5H), 6.91 (d, J = 8.4 Hz, 1H), 4.99 (s, 2H), 3.05 (s, 4H), 2.50 (s, 4H),
2.30 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 181.7, 157.8, 153.6, 137.6, 133.5, 131.6,
129.4, 128.6, 127.4, 124.9, 117.5, 111.4, 53.8, 45.7, 45.5, 44.47. IR (KBr, cm-1):
2920, 2807, 1747, 1613, 1455, 1329, 1163, 943, 747. ESI-MS: m/z 400.05 ([M+H+]).
Anal. Calcd for C20H21N3O4S: C, 60.13; H, 5.30; N, 10.52. Found: C, 60.29; H,
5.19; N, 10.71.
4.1.5.3.
5-[(4-Methylpiperazin-1-yl)sulfonyl]-1-β-naphthalenemethyl--1H-indole-2,3-dion
e (8a3). Compound 8a3 was prepared according to General Procedure above by using
compound 7a and 2-(bromomethyl)naphthalene. Yellow powder. Yield 88%. m.p.
1
218.1-220.3 °C. H NMR (400 MHz, CDCl3) δ 7.97 (d, J = 1.6 Hz, 1H), 7.88-7.79
(m, 5H), 7.52 (t, J = 4.0 Hz, 2H), 7.40 (dd, J = 8.4, 1.2 Hz, 1H), 6.95 (d, J = 8.4 Hz,
1H), 5.15 (s, 2H), 3.02 (s, 4H), 2.47 (s, 4H), 2.27 (s, 3H); 13C NMR (100 MHz,
26

CDCl3) δ 181.7, 157.8, 153.6, 137.7, 133.3, 133.2, 131.7, 130.9, 129.6, 127.9, 127.8,
126.9, 126.7, 126.6, 124.9, 124.7, 117.5, 111.4, 53.9, 45.9, 45.6, 44.7. IR (KBr, cm-1):
3052, 2945, 2797, 1737, 1615, 1454, 1349, 1129, 935, 754. ESI-MS: m/z 450.35
([M+H+]). Anal. Calcd for C24H23N3O4S: C, 64.13; H, 5.16; N, 9.35. Found: C,
63.96; H, 5.02; N, 9.41.
4.1.5.4.
1-Benzyl-5-{[4-(4-fluorophenyl)piperazin-1-yl]sulfonyl}-1H-indole-2,3-dione
(8b2). Compound 8b2 was prepared according to General Procedure above by using
compound 7b and benzyl bromide. Yellow powder. Yield 89%. m.p. 219.6-220.2 °C.
1H NMR (400 MHz, DMSO-d6) δ 7.96 (d, J = 8.4 Hz, 1H), 7.79 (s, 1H),7.46 (d, J =
7.2 Hz, 2H), 7.35 (t, J = 7.2 Hz, 2H), 7.29 (t, J = 7.2 Hz, 1H), 7.20 (d, J = 8.4 Hz, 1H),
7.03 (t, J = 8.8 Hz, 2H), 6.91 (m, 2H), 4.97 (s, 2H), 3.14 (s, 4H), 3.02 (s, 4H). 13C
NMR (100 MHz, DMSO-d6) δ 181.4, 159.1, 156.0 (d, J = 233 Hz), 153.9, 147.7,
137.3, 135.5, 129.6, 129.1, 128.1, 127.9, 123.4, 118.9, 118.5 (d, J = 7.0 Hz), 115.8 (d,
J = 22 Hz), 112.0, 49.1, 46.3, 43.7. IR (KBr, cm-1): 2958, 2854, 1741, 1618, 1508,
1331, 1160, 950, 827, 722. ESI-MS: m/z 480.31 ([M+H+]). Anal. Calcd for
C25H22FN3O4S: C, 62.62; H, 4.62; N, 8.76. Found: C, 62.56; H, 4.33; N, 8.61.
4.1.5.5.
5-{[4-(4-Fluorophenyl)piperazin-1-yl]sulfonyl}-1-β-naphthalenemethyl-1H-indole
-2,3-dione (8b3). Compound 8b3 was prepared according to General Procedure above
by using compound 7b and 2-(bromomethyl)naphthalene. Yellow powder. Yield 93%.
27

1
m.p. 217.6-219.5 °C. H NMR (400 MHz, CDCl3) δ 8.01 (s, 1H), 7.89-7.81 (m, 5H),
7.52 (t, J = 4.0 Hz, 2H), 7.42 (d, J = 8.4 Hz, 1H), 7.00-6.89 (m, 5H), 5.15 (s, 2H),
13
3.19 (d, J = 6.8 Hz, 8H). C NMR (100 MHz, CDCl3) δ 181.9, 159.2, 156.9 (d, J =
235 Hz), 154.0, 147.7, 137.3, 133.4, 129.7, 133.0, 132.9, 129.7, 128.8, 128.1(2×C),
126.9, 126.6, 126.3, 126.0, 123.4, 119.0, 118.6 (d, J = 7 Hz), 115.8 (d, J = 22 Hz),
112.0, 49.1, 46.3, 43.9. IR (KBr, cm-1): 3055, 2830, 1741, 1615, 1509, 1328, 1158,
947, 828, 747. ESI-MS: m/z 530.39 ([M+H+]). Anal. Calcd for C29H24FN3O4S: C,
65.77; H, 4.57; N, 7.93. Found: C, 65.84; H, 4.66; N, 8.07.
4.1.5.6.
1-Benzyl-5-{[4-(3-chlorobenzyl)piperazin-1-yl]sulfonyl}-1H-indole-2,3-dione
(8d2). Compound 8d2 was prepared according to General Procedure above by using
compound 7d and benzyl bromide. Yellow powder. Yield 93%. m.p. 129.1-130 °C.
1H NMR (400 MHz, CDCl3) δ 7.95 (d, J = 1.6 Hz, 1H), 7.86 (dd, J = 8.4, 1.6 Hz, 1H),
7.41-7.32 (m, 7H), 7.19 (dd, J = 5.6, 3.6 Hz, 2H), 6.92 (d, J = 8.4 Hz, 1H), 4.98 (s,
2H), 3.64 (s, 2H), 3.06 (s, 4H), 2.63 (s, 4H). 13C NMR (100 MHz, CDCl3) δ 181.7,
157.8, 153.6, 137.6, 134.6, 134.5, 133.7, 131.7, 130.9, 129.6, 129.3, 128.7, 128.6,
127.5, 126.7, 124.7, 117.5, 111.4, 51.9, 46.0, 44.5, 30.9. IR (KBr, cm-1): 3052, 2957,
2811, 1751, 1615, 1473, 1350, 1158, 954, 844, 757. ESI-MS: m/z 510.13 ([M+H+]).
Anal. Calcd for C26H24ClN3O4S: C, 61.23; H, 4.74; N, 8.24. Found: C, 61.09; H,
4.54; N, 8.17.
28

4.1.5.7.
5-{[4-(3-Chlorobenzyl)piperazin-1-yl]sulfonyl}-1-β-naphthalenemethyl-1H-indole
-2,3-dione (8d3). Compound 8d3 was prepared according to General Procedure above
by using compound 7d and 2-(bromomethyl)naphthalene. Yellow powder. Yield 91%.
1
m.p. 193.1-193.9 °C. H NMR (400 MHz, CDCl3) δ 7.96 (d, J = 1.6 Hz, 1H),
7.88-7.80 (m, 5H), 7.52 (t, J = 4.0 Hz, 2H), 7.42 (dd, J = 8.4, 1.6 Hz, 1H), 7.31 (br s,
1H), 7.25 (br s, 1H), 7.16 (br s, 1H), 6.96 (d, J = 8.4 Hz, 1H), 5.14 (s, 2H), 3.58 (s,
2H), 3.01 (s, 4H), 2.57 (s, 4H). 13C NMR (100 MHz, CDCl3) δ 181.7, 157.9, 153.6,
137.6, 134.5, 133.3, 133.1, 131.9, 131.0, 130.7, 129.7, 129.5, 128.6, 127.9, 127.8,
126.9, 126.7, 126.6, 124.9, 124.8, 117.5, 111.4, 51.9, 46.1, 44.8, 30.9. IR (KBr, cm-1):
3051, 2832, 1735, 1614, 1478, 1325, 1159, 935, 752. ESI-MS: m/z 560.21 ([M+H+]).
Anal. Calcd for C30H26ClN3O4S: C, 64.34; H, 4.68; N, 7.50. Found: C, 64.11; H,
4.74; N, 7.66.
4.1.5.8. 1-Methyl-5-[(4-phenylethylpiperazin-1-yl)sulfonyl]-1H-indole-2,3-dione
(8f1). Compound 8f1 was prepared according to General Procedure above by using
1
compound 7f and iodomethane. Yellow powder. Yield 93%. m.p. 183.9-184.6 °C. H
NMR (400 MHz, CDCl3) δ 8.01 (dd, J = 8.4, 1.6 Hz, 1H), 7.96 (d, J = 1.6 Hz, 1H),
7.26 (t, J = 7.2 Hz, 2H), 7.19 (d, J = 7.2 Hz, 1H), 7.15 (d, J = 7.2 Hz, 1H), 7.04 (d, J =
8.4 Hz, 1H), 3.33 (s, 3H), 3.07 (s, 4H), 2.73 (m, 2H), 2.63-2.60 (m, 6H). 13C NMR
(100 MHz, CDCl3) δ 181.8, 157.8, 154.3, 139.7, 137.8, 131.6, 128.6, 128.5, 126.2,
124.7, 117.3, 110.3, 59.7, 52.1, 46.1, 33.5, 26.7. IR (KBr, cm-1): 3025, 2952 2811,
29