Discovery of novel oxindole derivatives as potent α-glucosidase inhibitors

Article abstract of DOI:10.1016/j.bmc.2014.04.033

A series of 6-chloro-3-oxindole derivatives 1-25 were synthesized in high yields by the reaction of 6-chlorooxindole with different aromatic aldehydes in the presence of piperidine. All the synthesized compounds were isolated with E configuration. The structures were confirmed using spectroscopic techniques, including ¹H NMR and EIMS. These compounds showed varying degree of yeast α-glucosidase inhibition and seven were found as potent inhibitors of the enzyme. Compounds 2, 3, 4, 5, 6, 23, and 25 exhibited IC₅₀ values 2.71 ± 0.007, 11.41 ± 0.005, 37.93 ± 0.002, 15.19 ± 0.004, 24.71 ± 0.007, 17.33 ± 0.001, and 14.2 ± 0.002 μM, respectively, as compared to standard acarbose (IC₅₀, 38.25 ± 0.12 μM). Docking studies helped to find interactions between the enzyme and the active compounds. As a result of this study, oxindoles have been discovered as a new class of α-glucosidase inhibitors which have not been reported earlier.

Full text of DOI:10.1016/j.bmc.2014.04.033

Bioorganic & Medicinal Chemistry xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Discovery of novel oxindole derivatives as potent
inhibitors
a-glucosidase
a
b
b
c
Momin Khan a, , Muhammad Yousaf , Abdul Wadood , Muhammad Junaid , Muhammad Ashraf ,
⇑
Umber Alam c, Muhammad Ali d, Muhammad Arshad d, Zahid Hussain a, Khalid Mohammed Khan e,
⇑
a Department of Chemistry, Abdul Wali Khan University, Mardan 23200, Pakistan
b Department of Biochemistry, Abdul Wali Khan University, Mardan 23200, Pakistan
c Department of Biochemistry and Biotechnology, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan
d Department of Chemistry, COMSATS Institute of Information Technology, University Road, Abbottabad 22060, Pakistan
e H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of 6-chloro-3-oxindole derivatives 1–25 were synthesized in high yields by the reaction of
6-chlorooxindole with different aromatic aldehydes in the presence of piperidine. All the synthesized
compounds were isolated with E configuration. The structures were confirmed using spectroscopic tech-
Received 19 February 2014
Revised 18 April 2014
Accepted 19 April 2014
Available online xxxx
niques, including 1H NMR and EIMS. These compounds showed varying degree of yeast
a-glucosidase
inhibition and seven were found as potent inhibitors of the enzyme. Compounds 2, 3, 4, 5, 6, 23, and
25 exhibited IC50 values 2.71 0.007, 11.41 0.005, 37.93 0.002, 15.19 0.004, 24.71 0.007,
Keywords:
Oxindole
17.33 0.001, and 14.2 0.002
lM, respectively, as compared to standard acarbose (IC50,
38.25 0.12 M). Docking studies helped to find interactions between the enzyme and the active com-
l
a-Glucosidase
pounds. As a result of this study, oxindoles have been discovered as a new class of
a-glucosidase inhib-
Acarbose
Docking studies
itors which have not been reported earlier.
Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction
oxindole, and some of them are 3-spirooxindoles12 which possess
P-glycoprotein-mediated multiple drug resistance inhibitors,13
antibacterial, antiprotozoa.14
Oxindoles exhibit an extensive range of biological effects.1 Indo-
lin-2-one (Sunitinib) has been widely used in the treatment of gas-
trointestinal stromal tumors, and metastatic renal cell cancer.2
Oxindole-Schiff base copper(II) complexes have shown potential
antitumor activity towards different cells.3 Oxindole derivatives
such as indolidan and adibendan are used for the treatment of con-
gestive heart failure as these have strong vasodilatory, positive
inotropic and inodilatory actions.4 Amino methylene oxindole
derivatives are useful as antihypertensive agents.5 6-Chlorooxin-
dole, 6-fluorooxindole, 5-fluorooxindole, and 5-fluoro-1-methy-
loxindole showed sleep inducing actions.6 Oxindole-oxazolidinone
derivatives are the most important class of antimicrobials.7 Syn-
thetic oxindoles moiety containing compounds exhibit useful phar-
maceutical properties, including growth hormone secretagogues,8
analgesic,9 anti-inflammatory,10 serotonergic.11 Most of these com-
pounds contain a variety of substituents at the C-3 position of
a
-Glucosidase inhibitory activity of these compounds has not
been reported earlier and this work describes that oxindole deriv-
atives are potent inhibitors of this enzyme which is a target
enzyme in the treatment of diabetes mellitus.
a
-Glucosidases (EC3.2.1.20) is a family of enzymes located in
the brush border surface of small intestinal cells and causes hydro-
lysis of 1,4-glycosidic bond of starch and generate -glucose
a-D
which on absorption enters into the blood stream. It, therefore,
increases the post-prandial hyperglycemia. The inhibitors of this
enzyme are thus important in the treatment of type II diabetes
mellitus. A controlled digestion and absorption of monosaccha-
rides may help to prevent diabetes, hyperlipidemia, hyper lipopro-
teinemia and obesity.15,16 It also removes monosaccharides from
viral glycoproteins and hence its inhibitors may bring out changes
in cell-to-cell signaling and virus recognition to the cell. Therefore,
these inhibitors may find applications in the treatment of viral
infection and some types of cancers and as immunoregulatory
agents.15,17–19 These inhibitors proved the importance in glycosyl-
ation studies in cells.
⇑
Corresponding authors. Tel.: +92 937929122; fax: +92 937542188 (M.K.); tel.:
+92 2134824910; fax: +92 2134819018 (K.M.K.).
E-mail addresses: mominkhan@awkum.edu.pk, mominhej@yahoo.com (M.
Khan), hassaan2@super.net.pk, khalid.khan@iccs.edu (K.M. Khan).
http://dx.doi.org/10.1016/j.bmc.2014.04.033
0968-0896/Ó 2014 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Khan, M.; et al. Bioorg. Med. Chem. (2014), http://dx.doi.org/10.1016/j.bmc.2014.04.033

2
M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
R
2.2. a-Glucosidase activity
O
Piperidine/EtOH
Reflux, 3h
All synthesized 6-chloro-3-oxindole derivatives were tested for
-glucosidase inhibition studies and all of the compounds showed
>50% inhibition except one. Compounds 2, 3, 4, 5, 6, 23, 25 having
IC50 values (mean SEM, n = 3), 2.71 0.007, 11.41 0.005,
37.93 0.002, 15.19 0.004, 24.71 0.007, 17.33 0.001, and
O
O
a
N
N
R
Cl
Cl
H
H
1-25
Scheme 1. Synthesis of 6-chloro-3-oxindole derivatives 1–25.
14.2 0.002 lM, respectively, were found as potent inhibitors of
the enzyme. Molecular docking studies were performed to under-
stand the mechanism of enzyme inhibition and binding mode of
these novel oxindole derivatives inside the binding pocket of
2. Results and discussion
2.1. Chemistry
a-glucosidase.
All the synthesized compounds20 were isolated with E configu-
ration. For the determination of the structures of synthesized com-
pounds 1–25, 1H NMR, and EI spectroscopy were used. All
compounds gave a satisfactory CHN analysis (see Scheme 1 and
Table 1).
2.3. Molecular docking
From the molecular docking studies, it was observed that the top
ranked conformation of all the compounds fit well in the active site
and the oxindole moiety of these compounds showed interaction
Table 1
Inhibition studies of
a
-glucosidase of compounds 1–25
R
O
Cl
N
H
Compd #
R
IC50 SEMa
(lM)
Compd #
R
IC50 SEMa
(lM)
1'
1'
2'
3'
6'
5'
2'
6'
5'
1
410.55 0.91
14
109.98 0.07
OCH3
OCH3
CHO
1'
2'
1'
Cl
6'
5'
6'
5'
2
3
2.71 0.007
15
16
73.11 0.001
99.72 0.04
3'
OH
4'
OH
1'
NO2
6'
5'
2'
3'
6'
5'
11.41 0.005
3'
4'
O
Et
1'
4'
1'
OH
6'
5'
2'
3'
6'
5'
4
37.93 0.002
17
51.81 0.03
OC2H5
S
Me
1'
2'
1'
6'
5'
6'
2'
5
6
15.19 0.004
24.71 0.007
18
19
139.23 0.02
82.15 0.02
5'
OH
4'
4'
OMe
OH
1'
2'
6'
6'
5'
3'
OH
1'
3'
H3C
O
4'
1'
Cl
6'
5'
2'
3'
6'
5'
7
8
55.64 0.09
20
21
108.31 0.04
173.32 0.003
3'
Cl
O
Me
O
1'
4'
6'
5'
OH
5'
3'
72.19 0.008
4'
OCH3
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M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
3
Table 1 (continued)
Compd #
R
IC50 SEMa
(lM)
Compd #
R
IC50 SEMa
(lM)
1'
1'
2'
3'
6'
5'
2'
3'
6'
9
84.35 0.001
22
114.73 0.02
5'
NO2
2'
10'
7'
1'
6'
5'
2'
3'
9'
8'
3'
10
11
12
91.22 0.009
195.59 0.05
341.11 0.12
102.32 0.003
23
17.33 0.001
52.87 0.004
14.27 0.002
38.25 0.12
4'
5'
6'
N
H3C
CH3
1'
1'
Cl
2'
3'
6'
5'
Cl
24
3'
5'
4'
1'
4'
1'
OCH3
OCH3
6'
5'
6'
5'
2'
3'
25
OCH3
Me
Me
8'
2'
7'
6'
13
Acarbose
Standard inhibitor
3'
4'
5'
a
Data is mean of three independent experiments (mean SEM, n = 3).
with important residues of the binding pocket. In case of the most
active compound (2) four hydrogen bonds with the catalytically
active residues Asp214, Glu276, Asp349 were observed (Fig. 1).
The highest activity of this compound might be due to the presence
of two hydroxyl groups attached to the benzene ring. Both the
hydroxyl groups are involved in hydrogen bonding. The hydroxyl
groups are strong activating groups which polarize the molecule
and enable it to make several interactions with other residues. Sim-
ilarly, Compounds 5 and 6 having hydroxyl groups at meta and para
positions respectively, exhibited the good biological activities
against the enzyme. The docked conformation of compound 5
showed two hydrogen bonds with important active site residues
Asp214, and Asp349 whereas two hydrogen bonds were estab-
lished with other residues His348 and Arg212, which made it the
fourth active compound in the series (Fig. 2). In case of compound
6, the hydroxyl group was present in the meta position so, it polar-
ized the compound which enabled it to form five hydrogen bonds
and only one hydrogen bond was observed with important active
Figure 1. Binding mode of compound 2 in the active site of a-glucosidase.
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4
M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
residues Asp349 and four with other residues His348, Asn347,
Arg212, His111 which made it the sixth active compound in the ser-
ies (Fig. 3).
On the other hand, the least active compounds (1 and 12) con-
tain methoxy groups which do not contain hydrogen bond donor
or acceptor properties and both form one hydrogen bond with
the active residues Arg439 and Asp214, respectively (Figs. 4 and
5). A Similar profile was shown by compound 11 (Fig. 6).
contents were mixed, pre-incubated for 10 min at 37 °C and pre-
read at 400 nm. The reaction was initiated by the addition of 10
l
L
of 0.5 mM substrate (p-nitrophenyl glucopyranoside, Sigma Inc.).
After 30 min of incubation at 37 °C, the absorbance of p-nitrophenol
was measured at 400 nm using the Synergy HT 96-well plate reader,
BioTek, USA. Acarbose was used as positive control. All experiments
were carried out in triplicates (mean SEM, n = 3). Percent inhibi-
tion was calculated by the following equation:
2.4. In Vitro assay protocol for a-glucosidase
Inhibitionð%Þ ¼ ðAbs of ControlꢀAbs of Test=Abs of ControlÞꢁ100
The
modifications as given by Pierre et al.21 Total volume of 100
tion mixture contained, 70 L 50 mM phosphate buffer pH 6.8, 10
(0.5 mM in methanol) test compound, followed by the addition of
10 L (0.057 units, Sigma Inc.) enzyme solution in the buffer. The
a
-glucosidase inhibition activity was performed with slight
Active compound solutions were suitably diluted and their inhi-
bition studies were determined. Data obtained was used for the
determination of IC50 values (concentration at which there is 50%
enzyme inhibition) using EZ-Fit Enzyme Kinetics Software (Perrella
Scientific Inc. Amherst, USA).
lL reac-
l
lL
l
Figure 2. Binding mode of compound 5 in the active site of a-glucosidase.
Figure 3. Binding mode of compound 6 in the active site of -glucosidase.
a
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M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
5
Figure 4. Binding mode of compound 1 in the active site of a-glucosidase.
Figure 5. Binding mode of compound 12 in the active site of a-glucosidase.
2.5. Molecular docking
3AJ7, 1.30 Å resolution)26 with 72.4% of sequence identity with the
target was selected as the template. The 3D structure of -glucosi-
a
The 3D structure for
a
-glucosidase for Saccharomyces cerevisiae
dase for Saccharomyces cerevisiae was built using MOE homology
modeling tools. The developed 3D model was subjected to energy
minimization up to 0.05 gradients.
has not been solved up-to yet. However, only few homology models
has been reported.22–24 So, we developed the 3D model for
a
-
glucosidase for Saccharomyces cerevisiae by a comparative homol-
Before docking, ligands and protein were prepared using
MOE2010.11. Three dimensional structure of all synthesized com-
pounds was built using the Molecular Builder program imple-
mented in MOE. Finally, a database was created in which all the
ligands were converted into their respective 3D structures and this
database was used as input file MOE-docking. Subsequently, the
energy of compounds present in the database was minimized up
to 0.05 Gradient using MMFF 94x force field. Energy minimization
ogy modeling technique using the same protocol as described by
Burke et al.25 The primary sequence of
a-glucosidase from Saccha-
romyces cerevisiae was retrieved from UniProt protein resource data
bank (http://www.uniprot.org/) under the access code P53341.
Template search was performed using MOE-Search tools against
the PDB databank implemented in MOE2010.11. The crystallo-
graphic structure of Saccharomyces cerevisiae isomaltase (PDB code
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6
M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
Figure 6. Binding mode of compound 11 in the active site of a-glucosidase.
of the database was followed by the preparation of protein for
docking purposes. Most macromolecular crystal structures contain
little or no hydrogen coordinate data due to limited resolution and
thus protonation was done prior to docking using Protonate 3D
tools. Protonation was followed by energy minimization up to
0.05 Gradient using Amber 99 force field. The database was docked
into the active site of protein using the Triangular Matching dock-
ing method and 30 conformations of each ligand protein complex
were generated with docking score. Each complex was analyzed
for interactions and their 3D images were taken.
of hexane–ethyl acetate (25 mL) and dried to afford compounds
1–25.20 1H NMR, EI spectroscopy and CHN analysis were used for
the determination of their structures.
4.1.1. (E)-3-(3, 4-Dimethoxybenzylidene)-6-chloroindolin-2-
one (1)
Yield: 0.27 g (85%); 1H NMR (400 MHz, DMSO-d6): d 10.67 (s,
1H, NH), 8.64 (d, 1H, J2 ,6 = 1.5 Hz, H-20), 7.83 (dd, 1H, J6 ,2 = 1.5,
0
0
0
0
J6 ,5 = 8.5 Hz, H-60), 7.78 (s, 1H, @CH), 7.69 (d, 1H, J4,5 = 8.0 Hz, H-
0
0
4), 7.06 (d, 1H, J5 ,6 = 8.5 Hz, H-50),7.03 (dd, 1H, J5,7 = 1.5,
J5,4 = 8.0 Hz, H-5), 6.83 (d, 1H, J7,5 = 1.5 Hz, H-7), 3.83 (s, 3H,
AOCH3), 3.82 (s, 3H, AOCH3); MS: m/z (rel. abund.%) 315 (M+,
100), 272 (25), 166 (33), 140 (27); Anal. Calcd for C17H14ClNO3
(315.75): C, 64.67; H, 4.47; Cl, 11.23; N, 4.44; O, 15.20; Found: C,
64.65; H, 4.46; N, 4.44.
0
0
3. Conclusions
6-Chloro-3-oxindole derivatives were synthesized and their
inhibitory potential was evaluated against
All compounds showed -glucosidase inhibitory potential. Com-
pounds 2, 3, 4, 5, 6, 23, 25 exhibited an excellent inhibition with
IC50 values between 2.71 0.007 and 37.93 0.002 M. Conse-
a-glucosidase enzyme.
a
4.1.2. (E)-3-(3, 4-Dihydroxybenzylidene)-6-chloroindolin-2-
one (2)
l
Yield: 0.24 g (83%); 1H NMR (300 MHz, DMSO-d6): d 09.65 (s,
quently, in silico studies were performed to recognize the binding
mode of these compounds.
0
0
1H, NH), 7.73 (d, 1H, J4,5 = 8.0 Hz, H-4), 7.64 (d, 1H, J5 ,6 = 8.5 Hz,
H-50), 7.49 (s, 1H, @CH), 7.16 (d, 1H, J2 ,6 = 2.0 Hz, H-20), 6.95 (dd,
0
0
1H, J5,7 = 2.0, J5,4 = 8.0 Hz, H-5), 6.86(d, 1H, J7,5 = 2.0 Hz, H-7),
+
4. Materials and methods
6.79(1H, J6 ,5 = 8.5 Hz, H-60); MS: m/z (rel. abund.%) 287 (M ,
100), 271 (4.9), 254 (10), 240 (15); Anal. Calcd for C15H10ClNO3
(287.70): C, 62.62; H, 3.50; Cl, 12.32; N, 4.87; O, 16.68; Found: C,
62.61; H, 3.52; N, 4.88.
0
0
NMR experiments were performed on Advance Bruker AM 300,
400 and 500 MHz NMR machines. Electron impact mass spectra
(EIMS) were recorded on a Finnigan MAT-311A, Germany. Thin
layer chromatography (TLC) was performed on pre-coated silica
gel aluminum plates (Kieselgel 60, 254, E. Merck, Germany). Chro-
matograms were visualized by UV at 254 and 365 nm.
4.1.3. (E)-3-(2-Nitrobenzylidene)-6-chloroindolin-2-one (3)
Yield: 0.245 g (81%); 1H NMR (300 MHz, DMSO-d6): d 10.82 (s,
1H, NH), 8.31 (d, 1H, J3 ,4 = 8.0 Hz, H-30), 7.88 (s, 1H, @CH), 7.86–
7.75 (m, 2H, H-4/40), 6.93–6.85 (m, 2H, H-50/60), 6.89 (d, 1H,
J5,4 = 8.0 Hz, H-5), 6.87 (d, 1H, J7,5 = 2.0 Hz, H-7); MS: m/z (rel.
abund.%) 300 (M+, 3), 270 (2), 254 (23), 219 (7); Anal. Calcd for
0
0
4.1. General procedure for the synthesis of compounds 1–25
Synthesis of 6-chlorooxindole derivatives was carried out by
refluxing 6-chlorooxindole with different aromatic aldehydes in
ethanol in the presence of a catalytic amount of piperidine. The
reaction mixture was refluxed for 3 h. After completion of reaction
as determined by TLC analysis, the contents were cooled and con-
centrated at reduced pressure to afford solid 3-oxindole deriva-
tives. The product was washed with equal volumes of a mixture
C
15H9ClN2O3 (300.70): C, 59.91; H, 3.02; Cl, 11.79; N, 9.32; O,
15.96; Found: C, 59.91; H, 3.03; N, 9.33.
4.1.4. (E)-3-(3-Ethoxy-2-hydroxybenzylidene)-6-chloroindolin-
2-one (4)
Yield: 0.23 g (73%); 1H NMR (300 MHz, DMSO-d6): d 10.69 (s,
1H, NH), 7.72 (s, 1H, @CH), 7.46 (d, 1H, J4,5 = 8.0 Hz, H-4), 7.15(d,
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M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
7
1H, J4 ,5 = 7.5 Hz, H-40), 7.05 (d, 1H, J6 ,5 = 7.5 Hz, H-60), 6.92–6.82
(m, 3H, H-50/5/7), 4.130 (q, 2H, J = 5.5 Hz, -OCH2), 1.36 (t, 3H,
J = 5.5 Hz, -CH2CH3); MS: m/z (rel. abund.%) 315 (M+, 100), 298
(54), 286 (71), 270 (53); Anal. Calcd for C17H14ClNO3 (315.75): C,
64.67; H, 4.47; Cl, 11.23; N, 4.44; O, 15.20; Found: C, 64.68; H,
4.46; N, 4.44.
7.54–7.45 (m, 5H, H-20/30/40/50/60), 6.90 (dd, 1H, J5,7 = 2.0,
J5,4 = 8.0 Hz, H-5), 6.88 (d, 1H, J7,5 = 2.0 Hz, H-7); MS: m/z (rel.
abund.%) 255 (M+, 100), 227 (34), 190 (10), 178 (37); Anal. Calcd
for C15H10ClNO (255.70): C, 70.46; H, 3.94; Cl, 13.87; N, 5.48; O,
6.26; Found: C, 70.49; H, 3.91; N, 5.48.
0
0
0
0
4.1.12. (E)-3-(2,3,4-Trimethoxybenzylidene)-6-chloroindolin-2-
one (12)
4.1.5. (E)-3-(3-Hydroxybenzylidene)-6-chloroindolin-2-one (5)
Yield: 0.20 g (74%); 1H NMR (300 MHz, DMSO-d6): d 10.73 (s,
1H, NH), 9.90 (br.s, 1H, AOH), 7.57 (s, 1H, @CH),7.54(d, 1H,
Yield: 0.28 g (81%); 1H NMR (500 MHz, DMSO-d6): d 10.69 (s,
1H, NH), 7.61 (s, 1H, @CH), 7.49 (d, 1H, J6 ,5 = 8.5 Hz, H-60), 7.45
0
0
J4,5 = 8.5 Hz, H-4), 7.31(t, 1H, J5 (4 ,6 )= 8.5 Hz, H-50), 7.09–7.01 (m,
2H, H-20/60), 6.94–6.6.85 (m, 3H, H-40/5/7); MS: m/z (rel. abund.%)
271 (M+, 100), 266 (20), 243 (31), 178 (32); Anal. Calcd for C15H10-
ClNO2 (271.70): C, 66.31; H, 3.71; Cl, 13.05; N, 5.16; O, 11.78;
Found: C, 66.31; H, 3.70; N, 5.18.
0
0
0
(d, 1H, J4,5 = 9.0 Hz, H-4), 6.95 (d, 1H, J5 ,6 = 8.5 Hz, H-50), 6.89
(dd, 1H, J5,7 = 2.0, J5,4 = 9.0 Hz, H-5), 6.87 (d, 1H, J7,5 = 2.0 Hz, H-7),
3.87 (s, 3H, AOCH3), 3.82 (s, 3H, AOCH3), 3.78 (s, 3H, AOCH3);
MS: m/z (rel. abund.%) 345 (M+, 100), 314 (), 299 (17), 270 (10);
Anal. Calcd for C18H16ClNO4 (345.78): C, 62.52; H, 4.66; Cl, 10.25;
N, 4.05; O, 18.51; Found: C, 62.52; H, 4.65; N, 4.04.
0
0
4.1.6. (E)-3-(4-Hydroxybenzylidene)-6-chloroindolin-2-one (6)
Yield: 0.22 g (82%); 1H NMR (400 MHz, DMSO-d6): d 10.67 (s,
1H, NH), 8.37 (d, 1H, J4,5 = 8.5 Hz, H-4), 7.73–7.56 (m, 3H, H-20/60/
@CH), 6.93–6.80 (m, 4H, H-5/7/20/60); MS: m/z (rel. abund.%) 271
(M+, 100), 243 (57), 208 (27), 178 (35); Anal. Calcd for C15H10ClNO2
(271.70): C, 66.31; H, 3.71; Cl, 13.05; N, 5.16; O, 11.78; Found: C,
66.30; H, 3.73; N, 5.17.
4.1.13. (E)-6-Chloro-3-(naphthalene-1-ylmethylene) indolin-2-
one (13)
Yield: 0.23 g (77%); 1H NMR (500 MHz, DMSO-d6): d 10.54 (s,
1H, NH), 8.26 (s,1H, H-10), 8.04–7.93 (m, 3H, H-30/40/70), 7.82 (s,
1H, @CH), 7.77 (d, 1H, J5 ,6 = 8.5 Hz, H-50), 7.62–7.56 (m, 2H, H-4/
0
0
60), 7.52 (d, 1H, J8 ,7 = 8.5 Hz, H-80), 6.90–6.88 (m, 2H, H-5/7); MS:
m/z (rel. abund.%) 305 (M+, 100), 277 (30), 269 (13), 241 (25); Anal.
Calcd for C19H12ClNO (305.76): C, 74.64; H, 3.96; Cl, 11.60; N, 4.58;
O, 5.23; Found: C, 74.66; H, 3.97; N, 4.55.
0
0
4.1.7. (E)-3-(2,4-Dichlorobenzylidene)-6-chloroindolin-2-
one (7)
Yield: 0.27 g (83%); 1H NMR (400 MHz, DMSO-d6): d 10.85 (s,
1H, NH), 7.84 (d, 1H, J3 ,5 = 2.0 Hz, H-30), 7.77 (d, 1H, J4,5 = 8.0 Hz,
0
0
4.1.14. (E)-4-((6-Chloro-2-oxoindolin-3-
H-4), 7.57 (dd, 1H, J5 ,3 = 2.0, J5 ,6 = 8.5 Hz, H-50), 7.53 (s, 1H,
0
0
0
0
ylidene)methyl)benzaldehyde (14)
@CH), 7.11 (d, 1H, J6 ,5 = 8.5 Hz, H-60), 6.89–6.88 (m, 2H, H-5/7);
MS: m/z (rel. abund.%) 323 (M+, 4), 288 (100), 253 (18), 224 (5);
Anal. Calcd for C15H8Cl3NO (324.59): C, 55.50; H, 2.48; Cl, 32.77;
N, 4.32; O, 4.93; Found: C, 55.48; H, 2.50; N, 4.31.
0
0
Yield: 0.22 g (77%); 1H NMR (400 MHz, DMSO-d6): d 10.12 (s,
1H, NH), 10.06 (s, 1H, CHO), 8.43(d, 1H, J4,5 = 8.0 Hz, H-4), 8.02
(d, 2H, J2 ,3 /6 ,5 = 7.5 Hz, H-20/60), 7.86 (d, 2H, J3 ,2 /5 ,6 = 7.5 Hz, H-
30/50), 7.69 (s, 1H, @CH),6.90–6.84 (m, 2H, H-5/7); MS: m/z (rel.
abund.%) 297 (M+, 100), 254 (22), 191 (10), 178 (19); Anal. Calcd
for C16H10ClNO2 (283.71): C, 67.74; H, 3.55; Cl, 12.50; N, 4.94; O,
11.28; Found: C, 67.74; H, 3.54; N, 4.93.
0
0
0
0
0
0
0
0
4.1.8. (E)-3-(2-Hydroxy-3-methoxybenzylidene)-6-
chloroindolin-2-one (8)
Yield: 0.25 g (82%); 1H NMR (300 MHz, DMSO-d6): d 10.70 (s,
1H, NH), 9.41 (s, 1H, OH), 7.71 (s,1H, @CH), 7.56 (d, 1H,
4.1.15. (E)-3-(2-Chlorobenzylidene)-6-chloroindolin-2-one (15)
Yield: 0.21 g (74%); 1H NMR (500 MHz, DMSO-d6): d 10.82 (s,
J4,5 = 8.0 Hz, H-4), 7.16 (d, 1H, J6 ,5 = 7.5 Hz, H-60), 7.08 (d, 1H,
0
0
J4 ,5 = 7.5 Hz, H-40), 6.92–6.85 (m, 3H, H-5/7/50), 3.84 (s, 3H,
AOCH3); MS: m/z (rel. abund.%) 301 (M+, 100), 284 (74), 273
(12), 230 (18); Anal. Calcd for C16H12ClNO3 (301.72): C, 63.69; H,
4.01; Cl, 11.75; N, 4.64; O, 15.91; Found: C, 63.70; H, 4.01; N, 4.65.
0
0
0
0
1H, NH), 7.74 (d, 1H, J4,5 = 7.0 Hz, H-4), 7.64 (dd, 1H, J3 ,5 = 1.5,
J3 ,4 = 8.0 Hz, H-30), 7.61 (s, 1H, @CH), 7.52 (td, 1H, J4 ,6 = 1.5,
0
0
0
0
J4 (3 ,5 ) = 8.0 Hz, H-40), 7.48 (td, 1H, J5 ,3 = 1.5, J5 (4 ,6 ) = 8.0 Hz, H-
0
0
0
0
0
0
0
0
50), 7.10 (d, 1H, J6 ,5 = 8.0 Hz, H-60), 6.88–6.87 (m, 2H, H-5/7); MS:
m/z (rel. abund.%) 289 (M+, 11), 254 (100), 219 (16), 190 (12); Anal.
Calcd for C15H9Cl2NO (290.14): C, 62.09; H, 3.13; Cl, 24.44; N, 4.83;
O, 5.51; Found: C, 62.08; H, 3.13; N, 4.84.
0
0
4.1.9. (E)-3-(4-Nitrobenzylidene)-6-chloroindolin-2-one (9)
Yield: 0.24 g (81%); 1H NMR (400 MHz, DMSO-d6): d 10.84 (s, 1H,
NH), 8.35 (d, 2H, J3 ,2 /5 ,6 = 8.7 Hz, H-30/50), 7.94 (d, 2H, J2 ,3 /6 ,5
=
0
0
0
0
0
0
0
0
8.7 Hz, H-20/60), 7.71 (s, 1H, @CH), 6.90–6.85 (m, 2H, Hz, H-5/7);
MS: m/z (rel. abund.%) 300 (M+, 100), 272 (18), 254 (30), 191 (47);
Anal. Calcd for C15H9ClN2O3 (300.70): C, 59.91; H, 3.02; Cl, 11.79;
N, 9.32; O, 15.96; Found: C, 59.93; H, 3.00; N, 9.33.
4.1.16. (E)-3-(4-Ethoxybenzylidene)-6-chloroindolin-2-one (16)
Yield: 0.255 g (85%); 1H NMR (500 MHz, DMSO-d6): d 10.70 (s,
1H, -NH), 7.69 (d, 2H, J2 ,6 /3 ,5 = 8.0, H-20/60), 7.63 (d, 1H,
0
0
0
0
0
0
0
J4,5 = 8.0 Hz, H-4), 7.60 (s, 1H, @CH), 7.06 (d, 2H, J3 ,5 /2 ,6 = 8.0, H-
30/50), 7.01 (dd, 1H, J5,7 = 1.5, J5,4 = 8.0 Hz, H-5), 6.87 (d, 1H,
J7,5 = 1.5 Hz, H-7), 4.12 (q, 2H, J5,4 = 7.0 Hz, AOCH2), 1.34 (t, 3H,
J5,4 = 7.0 Hz, ACH2CH3); MS: m/z (rel. abund.%) 299 (M+, 100), 271
(60), 178 (31), 152 (30); Anal. Calcd for C17H14ClNO2 (299.75): C,
68.12; H, 4.71; Cl, 11.83; N, 4.67; O, 10.68; Found: C, 68.13; H,
4.72; N, 4.67.
4.1.10. (E)-3-(4-(Dimethylamino)benzylidene)-6-chloroindolin-
2-one (10)
Yield: 0.24 g (80%); 1H NMR (500 MHz, DMSO-d6): d 10.59 (s,
0
0
0
0
1H, NH), 7.75 (d, 1H, J4,5 = 8.0 Hz, H-4),7.63 (d, 2H, J2 ,3 /6 ,5
=
9.0 Hz, H-20/60), 7.54 (s, 1H, @CH), 6.93 (dd, 1H, J5,7 = 2.0,
J5,4 = 8.0 Hz, H-5), 6.86 (d, 1H, J7,5 = 2.0 Hz, H-7), 6.81(d, 2H,
J3 ,2 /5 ,6 = 9.0 Hz, H-30/50),3.02 (s, 6H, N(CH3)2); MS: m/z (rel.
0
0
0
0
abund.%) 298 (M+, 100), 281 (6), 269 (7), 254 (8); Anal. Calcd for
4.1.17. (E)-3-(4-(Methylthio)benzylidene)-6-chloroindolin-2-
one (17)
C17H15ClN2O (298.77): C, 68.34; H, 5.06; Cl, 11.87; N, 9.38; O,
Yield: 0.265 g (88%); 1H NMR (300 MHz, DMSO-d6): d 10.74 (s,
1H, ANH), 8.36 (d, 1H, J4,5 = 8.5 Hz, H-4), 7.71–7.56 (m, 3H, H-20/
5.36; Found: C, 68.37; H, 5.04; N, 9.40.
60/7), 7.39 (d, 2H, J3 ,5 /2 ,6 = 8.0, H-30/50), 6.92–6.87 (m, 2H, H-5/
@CH); MS: m/z (rel. abund.%) 301 (M+, 100), 258 (24), 178 (18),
63 (31); Anal. Calcd for C16H12ClNOS (301.79): C, 63.68; H, 4.01;
0
0
0
0
4.1.11. (E)-3-Benzylidene-6-chloroindolin-2-one (11)
Yield: 0.22 g (86%); 1H NMR (500 MHz, DMSO-d6): d 10.76 (s,
1H, NH), 7.69 (d, 1H, J4,5 = 8.0 Hz, H-4),7.66 (s, 1H, @CH),
Please cite this article in press as: Khan, M.; et al. Bioorg. Med. Chem. (2014), http://dx.doi.org/10.1016/j.bmc.2014.04.033

8
M. Khan et al. / Bioorg. Med. Chem. xxx (2014) xxx–xxx
Cl, 11.75; N, 4.64; O, 5.30; S, 10.62; Found: C, 63.66; H, 4.03; N,
4.66.
(35); Anal. Calcd for C23H14ClNO (355.82): C, 77.64; H, 3.97; Cl,
9.96; N, 3.94; O, 4.50; Found: C, 77.65; H, 3.97; N, 3.92.
4.1.18. (E)-3-(3-Methoxybenzylidene)-6-chloroindolin-2-one
(18)
4.1.24. (E)-3-(2,6-Dichlorobenzylidene)-6-chloroindolin-2-one
(24)
Yield: 0.24 g (84%); 1H NMR (500 MHz, DMSO-d6): d 10.75 (s,
1H, ANH), 7.63 (s, 1H, @CH), 7.52 (d, 1H, J4,5 = 8.0 Hz, H-4), 7.43
Yield: 0.22 g (76%); 1H NMR (500 MHz, DMSO-d6): d 10.86 (s,
1H, ANH), 7.65 (d, 2H, J4,5/5 ,4 = 8.0 Hz, H-4/50), 7.53 (t, 1H,
0
0
(t, 1H, J5 (4 ,6 ) = 8.0, H-50), 7.24(t, 1H, J4 (3 ,5 ) = 8.0, H-40), 7.23 (d,
J4 (3 ,5 ) = 8.0, H-40), 7.46 (s, 1H, @CH), 6.89–6.87 (m, 2H, H-50/7),
0
0
0
0
0
0
0
0
0
+
1H, J6 ,5 = 8.0 Hz, H-60), 7.04 (d, 1H, J3 ,4 = 8.0 Hz, H-30), 6.93 (dd,
1H, J5,7 = 1.5, J5,4 = 8.0 Hz, H-5), 6.88 (d, 1H, J7,5 = 1.5 Hz, H-7),
3.79 (s, 3H, AOMe); MS: m/z (rel. abund.%) 285 (M+, 100), 178
(59), 152 (32), 63 (56); Anal. Calcd for C16H12ClNO2 (285.72): C,
67.26; H, 4.23; Cl, 12.41; N, 4.90; O, 11.20; Found: C, 67.28; H,
4.22; N, 4.88.
6.47 (d, 1H, J3 ,4 = 8.0 Hz, H-30); MS:m/z (rel. abund.%) 323 (M ,
05), 287 (100), 253 (22), 83 (23); Anal. Calcd for C15H8Cl3NO
(324.59): C, 55.50; H, 2.48; Cl, 32.77; N, 4.32; O, 4.93; Found: C,
55.48; H, 2.48; N, 4.33.
0
0
0
0
0
0
4.1.25. (E)-3-(2,4-Dimethylbenzylidene)-6-chloroindolin-2-one
(25)
4.1.19. (E)-3-(2-Hydroxy-5-methoxybenzylidene)-6-
chloroindolin-2-one (19)
Yield: 0.24 g (84%); 1H NMR (300 MHz, DMSO-d6): d 10.74 (s,
1H, ANH), 7.68 (s, 1H, @CH), 7.46 (d, 1H, J4,5 = 7.5 Hz, H-4), 7.17–
7.10 (m, 3H, H-5/50/60), 6.86–6.84 (m, 2H, H-30/7), 2.33 (s, 3H,
-Me), 2.26 (s, 3H, -Me); MS: m/z (rel. abund.%) 283 (M+,58), 266
(97), 231 (100), 51 (79); Anal. Calcd for C17H14ClNO (283.75): C,
71.96; H, 4.97; Cl, 12.49; N, 4.94; O, 5.64; Found: C, 71.96; H,
4.98; N, 4.94.
Yield: 0.25 g (83%); 1H NMR (300 MHz, DMSO-d6): d 10.68 (s,
1H, ANH), 9.53 (s, 1H, AOH), 7.68 (s, 1H, @CH), 7.52 (d, 1H,
J4,5 = 8.0 Hz, H-4), 7.14 (d, 1H, J7,5 = 1.5 Hz, H-7), 6.96–6.86 (m,
4H, H-5/30/40/60), 3.68 (s, 3H, AOMe); MS: m/z (rel. abund.%) 301
(M+, 100), 152 (23), 75 (34), 53 (77); Anal. Calcd for C16H12ClNO3
(301.72): C, 63.69; H, 4.01; Cl, 11.75; N, 4.64; O, 15.91; Found: C,
63.70; H, 4.00; N, 4.64.
Acknowledgements
4.1.20. (E)-3-(4-Methoxybenzylidene)-6-chloroindolin-2-one
(20)
This work was financially supported by HEC, Pakistan, under
IPFP Program for Universities. Project No: PM IPFP/HRD/HEC/
2011/2764.
Yield: 0.20 g (70%); 1H NMR (500 MHz, DMSO-d6): d 10.70 (s,
1H, ANH), 7.70 (d, 2H, J2 ,6 /3 ,5 = 8.5, H-20/60), 7.61 (s, 1H, @CH),
0
0
0
0
7.08 (d, 2H, J3 ,5 /2 ,6 = 8.5, H-30/50), 7.02 (d, 1H, J4,5 = 8.0 Hz, H-4),
6.92 (dd, 1H, J5,7 = 2.0, J5,4 = 8.0, Hz, H-5), 6.92 (d, 1H, J7,5 = 2.0 Hz,
H-7), 3.83 (s, 3H, AOMe); MS: m/z (rel. abund.%) 285 (M+, 100),
References and notes
0
0
0
1. Rudrangi, S. R. S.; Bontha, V. K.; Manda, V. R.; Bethi, S. Asian J. Res. Chem 2011, 4,
335.
242 (43), 178 (44), 152 (31); Anal. Calcd for
C16H12ClNO2
2. Silva, B. V.; Ribeiro, N. M.; Pinto, A. C.; Vargas, M. D.; Dias, L. C. J. Braz. Chem. Soc
2008, 19, 1244.
3. Kadin, S. B. Google Patents, 1985.
(285.72): C, 67.26; H, 4.23; Cl, 12.41; N, 4.90; O, 11.20; Found: C,
67.26; H, 4.22; N, 4.89.
4.
, Chin. Pharm. J., 2001, 53, 207.
5. Kyncl, J. J.; Winn, M. Google Patents, 1979.
6. Hardtmann, G. E., Google Patents, 1979.
4.1.21. (E)-6-chloro-3-(furan-2-ylmethylene)indolin-2-one (21)
Yield: 0.19 g (77%); 1H NMR (500 MHz, DMSO-d6): d 10.70 (s,
7. Josyula, V.P.; Luehr, G.; Gordeev, M., Google Patents, 2006.
8. Zaveri, N. T.; Jiang, F.; Olsen, C. M.; Deschamps, J. R.; Parrish, D.; Polgar, W.; Toll,
L. J. Med. Chem. 2004, 47, 2973.
9. Alcaraz, M.; Atkinson, S.; Cornwall, P.; Foster, A. C.; Gill, D. M.; Humphries, L. A.;
Keegan, P. S.; Kemp, R.; Merifield, E.; Nixon, R. A.; Noble, A. J.; O’Beirne, D.;
Patel, Z. M.; Perkins, J.; Rowa, P.; Sadler, P.; Singleton, J. T.; Tornos, J.; Watts, A.
J.; Woodland, I. A. Org. Process Res. Dev. 2005, 9, 555.
10. Kikuchi, C.; Hiranuma, T.; Koyama, M. Bioorg. Med. Chem. Lett. 2002, 12, 2549.
11. Gallagher, R., Jr.; Patricia, G. L.; James, W. W.; Hieble, J. P.; DeMarinis, R. M. J.
Med. Chem. 1985, 28, 1533.
12. Koguchi, Y.; Kohno, J.; Nishio, M.; Takahashi, K.; Okuda, T.; Ohnuki, T.;
Komatsubara, S. J. Antibiot. 2000, 53, 105.
1H, ANH), 8.61 (d, 1H, J5 ,4 = 3.2 Hz, H-50), 8.38 (s, 1H, @CH), 6.71
0
0
(d, 2H, J4 ,5 = 3.2 Hz, H-40), 6.84 (d, 1H, J7,5 = 2.0 Hz, H-7), 6.47
(dd, 1H, J5,7 = 2.0, J5,4 = 8.0 Hz, H-5), 5.61 (d, 1H, J4,5 = 8.0 Hz, H-
4),2.49 (s, 3H, ACH3); MS: m/z (rel. abund.%) 245 (M+, 100), 154
(60), 127 (27), 63 (33); Anal. Calcd for C13H8ClNO2 (245.66): C,
63.56; H, 3.28; Cl, 14.43; N, 5.70; O, 13.03; Found: C, 63.56; H,
3.27; N, 5.71.
0
0
13. Smith, C. D.; Zilfou, J. T.; Stratmann, K.; Patterson, G. M. L.; Moore, R. E. Mol.
Pharmacol. 1995, 47, 241.
14. Pajouhesh, H.; Parson, R.; Popp, F. D. J. Pharm. Sci. 1983, 72, 318.
15. Borges de Melo, E.; Gomes, A.; Carvalho, I. Tetrahedron 2006, 62, 10277.
16. Asano, N. Glycobiology 2003, 13, 93R.
17. Dennis, J. W.; Laferte, S.; Waghorne, C.; Breitman, M. L.; Kerbel, R. S. Science
1987, 236, 582.
18. Jacob, G. S. Curr. Opin. Struct. Biol. 1995, 5, 605.
4.1.22. (E)-3-(4-Methylbenzylidene)-6-chloroindolin-2-one (22)
Yield: 0.240 g (89%); 1H NMR (500 MHz, DMSO-d6): d 10.72 (s,
1H, ANH), 7.62 (s, 1H, @CH), 7.60 (d, 2H, J2 ,6 /3 ,5 = 8.0, H-20/60),
0
0
0
0
8.30 (d, 1H, J4,5 = 8.0 Hz, H-4), 7.33 (d, 2H, J3 ,5 /2 ,6 = 8.0, H-30/50),
6.92 (dd, 1H, J5,7 = 1.5, J5,4 = 8.0 Hz, H-5), 6.87 (s, 1H, H-7), 2.36 (s,
3H, Ph-Me); MS: m/z (rel. abund.%) 269 (M+, 100), 258 (24), 178
(18), 63 (31); Anal. Calcd for C16H12ClNO (269.73): C, 71.25; H,
4.48; Cl, 13.14; N, 5.19; O, 5.93; Found: C, 71.24; H, 4.48; N, 5.20.
0
0
0
0
19. Lee, H. Y.; Lee, D. S.; Kim, D. H.; Cho, S. K.; Lee, D. S. J. Microbiol. Biotechnol. 2011,
21, 263.
20. Khan, K. M.; Khan, M.; Ambreen, N.; Taha, M.; Rahim, F.; Rasheed, S.; Saied, S.;
Shafi, H.; Perveen, S.; Choudhary, M. I. Med. Chem. 2013, 9, 681.
21. Pierre, C.; Roland, R.; Tremblay; Dube, J. Y. Clin. Chem. 1978, 24, 208.
22. Ferreira, S. B.; Sodero, A. C.; Cardoso, M. F.; Lima, E. S.; Kaiser, C. R.; Silva, F. P.,
Jr.; Ferreira, V. F. J. Med. Chem. 2010, 53, 2364.
23. Park, J.; Ko, S.; Park, H. Bull. Korean Chem. Soc. 2008, 29, 921.
24. Roujeinikova, A.; Raasch, C.; Sedelnikova, S.; Liebl, W.; Rice, D. W. J. Mol. biol.
2002, 321, 149.
4.1.23. (E)-3-(Anthracen-10-ylmethylene)-6-chloroindolin-2-
one (23)
Yield: 0.27 g (76%); 1H NMR (500 MHz, DMSO-d6DMSO-d6): d
11.48 (s, 1H, ANH), 8.77 (s, 1H, H-60), 8.38 (s, 1H, @CH), 8.20 (d,
2H, J(2 ,3 )(10 ,9 ) = 8.5, Hz, H-20/100), 7.95 (d, 2H, J(5 ,6 )(7 ,8 ) = 8.5, Hz,
0
0
0
0
0
0
0
0
25. Guerreiro, L. R.; Carreiro, E. P.; Fernandes, L.; Cardote, T. A.; Moreira, R.;
Caldeira, A. T.; Guedes, R. C.; Burke, A. Bioorg. Med. Chem. 1911, 2013, 21.
26. Yamamoto, K.; Miyake, H.; Kusunoki, M.; Osaki, S. FEBS J. 2010, 277, 4205.
H-50/70), 7.57 (t, 2H, J3 (2 ,4 )=9 (8 ,10 ) = 8.5, H-30/90), 7.52 (t, 2H,
0
0
0
0
0
0
J4 (3 ,5 )=8 (7 ,9 ) = 8.5, H-40/80), 6.84 (d, 1H, J7,5 = 2.0 Hz, H-7), 6.47
(dd, 1H, J5,7 = 2.0, J5,4 = 8.0 Hz, H-5), 5.61 (d, 1H, J4,5 = 8.0 Hz, H-
4); MS: m/z (rel. abund.%) 355 (M+, 100), 338 (65), 291 (45), 131
0
0
0
0
0
0
Please cite this article in press as: Khan, M.; et al. Bioorg. Med. Chem. (2014), http://dx.doi.org/10.1016/j.bmc.2014.04.033