3-Alkenyl-2-oxindoles: Synthesis, antiproliferative and antiviral properties against SARS-CoV-2

Article abstract of DOI:10.1016/j.bioorg.2021.105131

Sets of 3-alkenyl-2-oxindoles (6,10,13) were synthesized in a facile synthetic pathway through acid dehydration (EtOH/HCl) of the corresponding 3-hydroxy-2-oxoindolines (5,9,12). Single crystal (10a,c) and powder (12a,26f) X-ray studies supported the stru

Full text of DOI:10.1016/j.bioorg.2021.105131

Bioorganic Chemistry 114 (2021) 105131
Contents lists available at ScienceDirect
Bioorganic Chemistry
journal homepage: www.elsevier.com/locate/bioorg
3
-Alkenyl-2-oxindoles: Synthesis, antiproliferative and antiviral properties
against SARS-CoV-2
a
,
*
b
c
d
d,e
Adel S. Girgis , Siva S. Panda , Aladdin M. Srour , Anwar Abdelnaser , Soad Nasr
,
f
f
f
f
f
Yassmin Moatasim , Omnia Kutkat , Ahmed El Taweel , Ahmed Kandeil , Ahmed Mostafa ,
Mohamed A. Ali , Nehmedo G. Fawzy , Mohamed S. Bekheit , ElSayed M. Shalaby ,
Lara Gigli , Walid Fayad , Ahmed A.F. Soliman
f
a
a
g
h
i
i
a
Department of Pesticide Chemistry, National Research Centre, Dokki, Giza 12622, Egypt
b
c
d
e
f
Department of Chemistry & Physics, Augusta University, Augusta, GA 30912, USA
Department of Therapeutic Chemistry, National Research Centre, Dokki, Giza 12622, Egypt
Institute of Global Health and Human Ecology, School of Sciences and Engineering, The American University in Cairo (AUC), Cairo 11835, Egypt
Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, D-89081 Ulm, Germany
Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12622, Egypt
X-Ray Crystallography Lab., Physics Division, National Research Centre, Dokki, Giza 12622, Egypt
Elettra-Sincrotrone Trieste, s.s. 14 Km 163.5 in Area Science Park, Basovizza (Trieste) 34149, Trieste, Italy
Drug Bioassay-Cell Culture Laboratory, Pharmacognosy Department, National Research Centre, Dokki, Giza, 12622. Egypt
g
h
i
A R T I C L E I N F O
A B S T R A C T
Keywords:
Indole
Sets of 3-alkenyl-2-oxindoles (6,10,13) were synthesized in a facile synthetic pathway through acid dehydration
(
(
EtOH/HCl) of the corresponding 3-hydroxy-2-oxoindolines (5,9,12). Single crystal (10a,c) and powder
12a,26f) X-ray studies supported the structures. Compounds 6c and 10b are the most effective agents syn-
Benzimidazole
Antitumor
SARS-CoV-2
VEGFR-2
c-Kit
thesized (about 3.4, 3.3 folds, respectively) against PaCa2 (pancreatic) cancer cell line relative to the standard
reference used (Sunitinib). Additionally, compound 10b reveals antiproliferative properties against MCF7
(
breast) cancer cell with IC50 close to that of Sunitinib. CAM testing reveals that compounds 6 and 10 demon-
strated qualitative and quantitative decreases in blood vessel count and diameter with efficacy comparable to
that of Sunitinib, supporting their anti-angiogenic properties. Kinase inhibitory properties support their multi-
targeted inhibitory activities against VEGFR-2 and c-kit in similar behavior to that of Sunitinib. Cell cycle
analysis studies utilizing MCF7 exhibit that compound 6b arrests the cell cycle at G1/S phase while, 10b reveals
accumulation of the tested cell at S phase. Compounds 6a and 10b reveal potent antiviral properties against
SARS-CoV-2 with high selectivity index relative to the standards (hydroxychloroquine, chloroquine). Safe profile
of the potent synthesized agents, against normal cells (VERO-E6, RPE1), support the possible development of
better hits based on the attained observations.
Docking
1
. Introduction
VEGFR (vascular endothelial growth factor receptor) inhibitor dis-
continued in 2002 during phase III clinical trials for colorectal cancer
Many 3-alkenyl-2-oxindole analogs were naturally isolated revealing
diverse biological properties [1]. Sunitinib (Sutent) which is a 3-alkenyl-
-oxindole derivative is an orally multi-target tyrosine kinase inhibitor
[4] (Fig. 1). Cancer is one of the most serious human health challenges
universally. It is the second life deadly disease after cardiovascular
disorders. WHO (World Health Organization) reported 1/6 deaths
globally is due to cancer in 2018 (9.6 million deaths) [5,6]. Although
many targeted drugs are developed and clinically approved, the asso-
ciated side effects and limited efficacies diminished their applications
and demanded the need for novel chemical entities with safer cures and
2
approved by FDA (Food and Drug Administration on Jan. 26, 2006 and
Nov. 16, 2017) for the treatment of gastrointestinal and advanced renal
cancers. It has been also approved for the treatment of pancreatic cancer
(
May 20, 2011) [2,3]. Semaxanib, another member of this family, is a
*
Corresponding author.
E-mail address: girgisas10@yahoo.com (A.S. Girgis).
https://doi.org/10.1016/j.bioorg.2021.105131
Received 17 May 2021; Accepted 24 June 2021
Available online 30 June 2021
0
045-2068/© 2021 Published by Elsevier Inc.

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
higher potencies [7].
disease). This is why multi-targeted inhibitors were developed which
can exhibit therapeutic potencies towards various mechanisms [8,9]. It
has been reported that cancer initiation and progression depend on
several receptors or singling pathways. This is why multi-targeted agents
can provide several advantages over mono-targeted therapies. Several
multi-target inhibitors (e.g. Sunitinib, Sorafenib, Altiratinib, Linifanib,
Many of the investigated anticancer agents/drugs obey “one-mole-
cule – one target – one disease” phenomenon. This allows the emerging
of an agent selectively targeting a single biological entity to avoid the
risk of off-target side effects. However, this hypothesis seems inadequate
for multi-genic diseases (such as cancer, Alzheimer’s or Parkinson’s
Fig. 1. Biologically active 3-alkenyl-2-oxindoles, multi-targeted anticancer agents and Treanda (Bendamustine).
2

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
and Regorafenib) were developed/approved, or investigated in clinical
trials [10] (Fig. 1).
unknown pathogen [59]. COVID-19 is a viral disease that belongs to the
family Coronaviridae and genus Betacoronavirus [60]. By May 2021
about 162.2 million patients with 3.364 million deaths were reported
worldwide [61]. Lack of available antiviral drugs/vaccines enforced the
pharmaceutical authorities/companies to test any agent/drug with
antiviral background (drug repurposing). Few agents were considered
due to urgent needs (Fig. 2) to control global pandemic but most of them
are with low potency and adverse effects [62]. This seems the top to-
day’s priority for the political and health authorities to save thousand
(s)/million(s) of human life and economic collapse. Recently, few N-
substituted isatins were reported as SARS-CoV-2 3CLpro inhibitors [63].
Due to this, the 3-alkenyl-2-oxindoles synthesized in the present study
are screened for their antiviral properties against SARS-CoV-2. The
recent reports describing the possibility for treating SARS-CoV-2 pa-
tients with anticancer drugs [64,65] in addition to the successful clinical
trial for treating colorectal
In our pursuit to develop novel antitumor agents [11–13], the pre-
sent study describes the synthesis of 3-alkenyl-2-oxindoles conjugated
with sulfonamide function. This fragment is an important component in
many clinically approved antitumor drugs {e.g. Belinostat (Beleodaq)
[
14,15], Dabrafenib (Tafinlar) [16,17], Pazopanib (Votrient) [18,19],
Vemurafenib (Zelboraf) [20,21] and Venetoclax (Venclexta) [22,23]}.
Benzimidazolyl heterocycle is also considered for conjugation with
the targeted compounds due to the diverse biological properties
exhibited by its derivatives such as antitumor [24–31], anti-
inflammatory [32], antitubercular [33–35], anti-HIV (human immuno-
deficiency virus) [36–38], α-glucosidase inhibition [39–41], cholines-
terase inhibitor useful to combat the neuromuscular disorders [42],
pancreatic lipase inhibitor useful for fat absorption control [43],
α
-amylase inhibitor useful for diabetes, obesity, and oral diseases [44]
and Rho-kinase inhibitor useful for treatment of glaucoma [45]. Treanda
Bendamustine hydrochloride) is a benzimidazolyl derivative approved
carcinoma patients with antiviral drugs solely or in combination
with anticancer drugs [66], also prompted the current study targeting
developing novel hits of dual functions (antiviral and antitumor) with
much attention to their safety profile towards normal cells.
(
by FDA (2008) for chronic lymphocytic leukemia [46,47].
Antiproliferative properties of the targeted agents are considered
against pancreatic (PaCa), colon (HCT116), and breast (MCF7) carci-
noma cell lines. Adoption of the mentioned cell lines for testing is due to
the high correlation of the synthesized agents with Sunitinib that show
efficacy/clinical application against them. Additionally, pancreatic
cancer is the twelfth most common cancer globally with 460,000 new
cases in 2018 [48]. It usually develops from exocrine (more common) or
neuroendocrine (less common with better prognosis) cells [49]. Colo-
rectal cancer is a malignant tumor arising from genetic and epigenetic
changes in colorectal epithelial cells [50]. Heredity, colon polyps, and
long-standing ulcerative colitis are major factors that cause colon cancer
2. Results and discussion
2.1. Chemistry
Reaction of 4-acetylphenyl alkanesulfonates 3a,b with isatins 4a,b
in absolute ethanol containing quantitative amount of diethylamine at
room temperature afforded the corresponding 4-[2-(3-hydroxy-2-oxoin-
dolin-3-yl)acetyl]phenyl alkanesulfonates 5a-d in good yields (Scheme
1). Compounds 5a-d were isolated from the conducted reactions in
adequate purity so, used directly in the next step without any further
purification. IR spectrum of 5a (example of the agents prepared) reveals
[
51]. Breast cancer is the second cause of female cancer (2.09 million
cases) with death incidence 627,000 globally in 2018 according to WHO
statistics [5].
ꢀ 1
the ketonic and indolyl carbonyl bands at
the hydroxyl, and indolyl NH as a broad–band at
methylene protons are diastereotopic shown as two doublet signals at δ
= 3.61, 4.09 (J = 17.5 Hz). The C NMR spectrum of 5a exhibits the
indolyl C-3 and C-
ν = 1701, 1675 cm beside
ꢀ
1
The chick chorioallantoic membrane (CAM) assay model can be
employed as an in vivo xenograft model for cancer cells. The cells form
tumor xenografts by seeding onto the chorioallantoic membrane as a
result, invasion occurs into a highly vascularized membrane. The CAM
model can also be used to study angiogenesis due to the high vascular-
ization of its membrane. The chorioallantoic membrane is composed
mostly of type IV collagen, which resembles the human epithelium
basement membrane [52–57].
The SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2)
seems the most major health care disaster declared by WHO (World
Health Organization) as a pandemic COVID-19 [58]. The story began in
December 2019 (Wuhan, China) due to novel pneumonia by an
ν = 3291 cm . The
H
1
3
2 at δ
carbonyl at δ
Acidic dehydration (EtOH/HCl) of 5 afforded directly (E)-4-[2-(2-
oxoindolin-3-ylidene)acetyl]phenyl alkanesulfonates in excellent
yields. 1H NMR spectrum of 6a shows the olefinic proton as a sharp
singlet at δ = 7.74. The indolyl and ketonic carbonyls are shown at δ
= 168.1, 190.0, respectively.
Similarly, N-[4-(2-(3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl)-N-
C
= 72.9, 178.2 respectively beside, the methylene and ketonic
C
= 45.7, 195.4, respectively.
6
H
C
Fig. 2. Repurposing drugs for COVID-19.
3

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Scheme 1. Synthetic route towards 5 and 6.
(
alkylsulfonyl)alkanesulfonamides 9a-d were obtained through the re-
Figs. S1–S108).
action of N-(4-acetylphenyl)-N-(alkylsulfonyl)alkanesulfonamide 8a,b
with the corresponding isatins 4a,b. Meanwhile, reaction of N-(4-ace-
tylphenyl)propane-1-sulfonamide (8c) with isatins 4a-c afforded the
corresponding N-{4-[2-(3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-N-
2.2. X-ray studies
Single crystals suitable for Synchrotron single-crystal X-ray diffrac-
tion experiments were obtained for the compounds 10a and 10c.
Compounds 10a and 10c crystallized in the monoclinic P21/c and
triclinic P-1 space groups, respectively. ORTEP views of the compounds
are shown in Fig. 3. In both structures, the 4-[2-(2-oxoindolin-3-ylidene)
acetyl]phenyl system seems almost planar, forming a dihedral angle of
(
propylsulfonyl)propane-1-sulfonamide 9e-g. This is presumably
formed due to propylsulfonate elimination from 8c, under the effect of
the reaction basic catalysis used followed by a simultaneous attack to
another molecule giving eventually the isolated products 9e-g. Acidic
dehydration of 9 afforded the corresponding 10 in good yields (Scheme
1
◦
◦
2
). H NMR of 10a-c reveal the olefinic proton as a singlet signal at δ
H
=
82.23 and 80.28 with the sulfonamide group of 10a and 10c,
respectively. In 10a the torsion angle defined by C29-C30-C31-C32 is
7
.74–7.80. Single crystal X-ray studies of compounds 10a,c support the
◦
E-configuration (Fig. 3).
-Hydroxy-3-[2-(1-alkyl-1H-benzo[d]imidazol-2-yl)-2-oxoethyl]
nearly planar (179.19 ). Whereas, in the other independent molecule
◦
3
the same angle defined by C9-C10-C11-C16 is 150.23 resulting in a loss
indolin-2-ones 12a-h were also obtained through base-catalyzed reac-
tion of 1-alkyl-2-acetylbenzimidazoles 11a,b with isatins 4a-e which are
formed in sufficient purity and used directly in the next step. Powder X-
ray studies of compounds 12a,f add conclusive support for the structure
of planarity. In both compounds, the intermolecular hydrogen bond
between the N(1, 3)H and the carbonyl group of the heterocycle with a
bond length of 2.02 Å and 1.972 Å, respectively, stabilize the crystal
structures (Supplementary Tables S1–S4, S8; Figs. S109, S110).
On the other hand, the indexing of the investigated X-ray powder
diffraction data of compounds 12a and 12f resulted in the triclinic P-1
(
Fig. 4). 3-[2-(1-Alkyl-1H-benzo[d]imidazol-2-yl)-2-oxoethylidene]
indolin-2-ones 13a–f could also be synthesized from the corresponding
2a-f through acidic dehydration. Acidic dehydration of 12 g,h under
1
and monoclinic P2 /n space group, respectively with one molecule per
1
the same reaction conditions afforded 13a as a sole product. This is
probably formed via cyclic-amino methylene elimination under the ef-
fect of the applied acidic reaction conditions (Scheme 3). 1H NMR
asymmetric unit in each (Fig. 4). The torsion angles defined by C14-C13-
◦
C12-C9 show different values. It is nearly planar (176.5 ) in compound
◦
12a and out of plane in compound 12f (72.79 ). As a consequence, the
◦
spectra of 13a-f reveal the olefinic proton as a sharp singlet at δ
H
=
benzimidazolyl and indolyl heterocycles form a dihedral angle of 79.63
◦
8
.66–8.85. The downfield shift shown by these analogs relative to 6a-c
and 49.02 in the 12a and 12f, respectively. Moreover, this fact leads to
and 10a-c can be attributed to the anisotropic effect of benzimidazolyl
a different intramolecular bond between the benzimidazolyl and indolyl
heterocycle (the spectral illustrations are presented in supplementary
heterocycles as in compound 12a is ruled by the N7-O15 bond distance
Scheme 2. Synthetic route towards 9 and 10.
4

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Fig. 3. ORTEP view of compounds (A) 10a and (B) 10c showing the atom-numbering scheme. H atoms are shown as small spheres of arbitrary radii.
Fig. 4. ORTEP view of compounds (A) 12a and (B) 12f showing the atom-numbering scheme. H atoms are shown as small spheres of arbitrary radii.
Scheme 3. Synthetic route towards 12 and 13.
of 2.69 Å. That is lost in the 12f and replaced by a slightly shorter N11-
Table 1
O1 bond distance of 2.52 Å. In the 12f there is a strong intermolecular H-
Antiproliferative properties of the tested compounds.
bond between the N(7)–H and the carbonyl group of the heterocycle
Entry
Compd.
IC50
(
μ
M) ± SE
with a bond length of 1.786 Å (Supplementary Tables S5–S7, S9;
Figs. S111, S112).
PaCa-2
MCF7
HCT116
1
2
3
4
5
6
7
6a
8.30 ± 0.44
5.60 ± 0.57
4.99 ± 0.29
6.91 ± 0.89
5.08 ± 0.57
6.18 ± 0.32
16.91 ± 0.95
6.85 ± 0.37
4.25 ± 0.23
4.28 ± 0.51
6.07 ± 0.83
4.15 ± 0.78
4.43 ± 0.47
3.97 ± 0.14
16.38 ± 0.70
12.77 ± 1.41
5.33 ± 0.46
20.96 ± 1.75
13.83 ± 1.06
>50.00 ± 0.84
5.03 ± 0.30
2
2
.3. Biological studies
6b
6c
10a
10b
10c
.3.1. Antiproliferative properties
Standard MTT technique was considered for determining the anti-
proliferative properties of the synthesized compounds utilizing Sunitinib
as a standard reference against pancreatic (PaCa-2), breast (MCF7), and
colon (HCT116) cancer cell lines [67]. Table 1 reveals the cytotoxic
Sunitinib
5

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
properties of the targeted 3-alkenyl-2-oxindoles in IC50
(
μ
M, concen-
2.3.3. Kinase inhibitory properties
trations exhibiting 50% cell growth inhibition relative to the control
experiment). It has been noticed that all the synthesized 3-alkenyl-2-
oxindoles 6a–c and 10a–c show remarkable antiproliferative proper-
ties against pancreatic cancer (PaCa-2) cell line with potency higher
than that of Sunitinib. Compounds 6c and 10b are the most effective
agents synthesized (about 3.4, 3.3 folds, respectively) relative to Suni-
tinib. Compound 6b also reveals high potency against PaCa2, three time
folds relative to Sunitinib. On the other hand compound 10b is the most
potent agent synthesized against MCF7 (breast) cancer cell line exhib-
iting IC50 close to that of the standard reference used (IC50 = 4.15, 3.97
µM for 10b and Sunitinib, respectively). Compounds 6b and 6c also
Angiogenesis is the formation of novel blood vessels/branches from
the existing ones [72]. The new blood vessels are useful for nutrient and
oxygen transportation to the endothelial cells that may stimulate and
proliferate forming new sprouts. Regulated angiogenesis is an important
process for embryonic development, reproduction, and wound healing
due to cell growth and tissue re-generation [73]. On the other hand,
dysregulated angiogenesis is observed in many diseases including solid
cancers. This is why targeting dysregulated angiogenesis seems an
important therapeutical approach for competing diverse cancer types
and sometimes has been considered preferable to other chemotherapies
to avoid the adverse effects on normal/healthy cells [74]. It has been
reported that vascular endothelial growth factor receptors are three
main categories (VEGFR-1, VEGFR-2, and VEGFR-3) responsible for
tumor angiogenesis [75,76]. VEGFR-2 is the main receptor capable for
anti-angiogenesis and controlling tumor proliferation [74].
reveal similar behavior with efficacy close to that of Sunitinib (IC50
.25, 4.28 µM for 6b and 6c, respectively). However, compound 6c is
the only synthesized analog with cytotoxic properties against HCT116
colon) cancer cell line close to the standard reference used (IC50 = 5.33
and 5.03 M corresponding to 6c and Sunitinib, respectively).
=
4
(
μ
Table 3 (Fig. 6) exhibits the VEFGR-2 inhibitory properties of the
promising antiproliferative 3-alkenyl-2-oxindoles (6a–c, 10a–c) syn-
thesized. From the exhibited data it has been noticed that, compound 6c
is the most potent VEGFR-2 inhibitor with 1.3 folds relative to that of
Sunitinib (standard reference used). This observation is comparable to
that shown by CAM testing (blood vessel diameter = 5.1, 5.0 mm by
compound 6c and Sunitinib, respectively). Compound 10c also reveals
promising VEGFR-2 inhibitory properties (IC50 = 53.36 nM, i.e. 0.89
fold relative to Sunitinib). This observation is comparable to the anti-
proliferative properties revealed for MCF7 (breast) cancer cell line (IC50
= 4.43, 3.97 µM for compound 10c and Sunitinib, respectively; i.e. 0.9
fold potency) and CAM testing (blood vessel diameter = 5.0 mm by both
compound 10c and Sunitinib). Additionally, the promising VEGFR-2
exhibited by compound 6a (IC50 = 54.03 nM) also supports the
revealed antiproliferative properties against MCF7 (IC50 = 6.85 µM).
The c-Kit receptor is a member of class III tyrosine kinase receptor
[77]. Overexpression of c-kit initiates cell proliferation and tumor cre-
ation [78]. Suppressing the c-kit was reported as an efficient therapeutic
strategy for controlling many cancer types [79–81]. It has been reported
that, the VEGFR-2 inhibitors may block/inhibit other tyrosine kinase
receptors (e.g. c-Kit, PDGFRs, FGFRs, and Flt-3); due to the structural
similarities so, can be recognized as multi-targeted tyrosine kinase in-
hibitors with accessibility against different cancer types [82]. Addi-
tionally, the chemical structural resemblance of the antiproliferative
agents synthesized and Sunitinib also prompted screening the inhibitory
properties of 6a–c and 10a–c towards c-kit. Considering that Sunitinib is
approved as multi-targeted inhibitor against various kinases including
VEGFR, PDGFR, FLT-3 and c-kit [83].
Based on the biological observations few SAR (structure–activity
relationships) can be assigned. Attachment of the ethyl group to the
sulfonate/sulfonamide fragment is critical in developing biological
properties comparable with the methyl group as revealed in pairs 6a/6b
and 10a/10b. It has also been noticed that in case of PaCa2 (pancreatic)
and HCT116 (colon) cancer cell lines, attachment of chlorine atom to the
indolyl heterocycle enhances the observed antiproliferative properties
of the sulfonate containing-compounds as shown in the pair 6b/6c. On
the other hand, utilization of benzimidazolyl heterocycle instead of the
substituted phenyl quenched the targeted biological properties (as
revealed in compounds 6a–c and 10a–c relative to compounds 13a–f).
This can be attributed to the high insolubility (with high melting point)
of the synthesized compounds 13 in aqueous media.
The cytotoxic properties of the effective agents synthesized (6a–c
and 10a–c) were also determined against non-cancer RPE1 (retinal
pigment epithelium) cell line. The observed data support the safety
profile of all the tested analogs against the utilized normal cell line (IC50
>
50
μ
M). Antiproliferative properties of all the tested agents are shown
in Supplementary Figs. S113–S116.
2
.3.2. CAM assay
CAMs treated with the proposed synthesized agents (the most
promising antiproliferative agents synthesized) 6a–c and 10a–c, control
vehicles, DMSO, PBS “Phosphate-buffered saline”, and ethanol) and
(
positive control (Sunitinib) showed a significant difference in blood
vessel number and diameter, either quantitatively (n = 4) or qualita-
tively (Fig. 5A). In detail, CAMs treated with vehicle only showed the
highest blood vessel diameters (14 mm). CAMs treated with Sunitinib
showed reduction in blood vessel diameters in comparison to control (5
mm). Compounds 6a–c significantly reduced the blood vessel diameters
to 3.2, 5.1, and 5.13 mm, respectively, compared to control. Compounds
Table 3 (Fig. 6) reveals the inhibitory properties of the tested com-
pounds against c-kit. It has been noticed that, compound 6c is a potent c-
kit inhibitor with efficacy higher than that of the standard reference
used, Sunitinib (IC50 = 72.35, 84.9 nM for 6c and Sunitinib, respec-
tively). These observations can support the exhibited antiproliferative
properties of 6c relative to Sunitinib as mentioned in the VEGFR-2
inhibitory observations. Compound 10c also reveals promising c-kit
inhibitory properties close to that of Sunitinib (IC50 = 81.7, 84.9 nM for
10c and Sunitinib, respectively). These observations are comparable to
their antiproliferative properties against MCF7 (breast) cancer cell line
(IC50 = 4.43, 3.97 µM for compound 10c and Sunitinib, respectively).
Generally, most of the revealed kinase (VEGFR-2 and c-kit) inhibitory
properties observed by the tested compounds are consistent with their
antitumor observations (Table 1). The slight differences shown are due
to the environmental experimental conditions applied (standard pro-
tocols). It can also conclude that the synthesized agents are multi-
targeted kinase receptor inhibitors (VEGFR-2 and c-kit).
1
0a–c also reduced the blood vessel diameters to 3.5, 2.7, and 5 mm,
respectively, compared to control (Fig. 5B, Table 2). In order to support
these observations, H&E (haematoxylin and eosin) staining for CAMs
was performed. In this regard, H&E staining confirmed the mentioned
observations (revealing reductions in the number of blood vessels) for
the CAMs treated with the positive control (Sunitinib) and the tested
agents 6a–c, 10a–c.
The CAM assay is one of the most utilized techniques for determi-
nation of anti-angiogenic effects [68]. This is attributed to the highly
vascularized membrane and that the chorioallantoic membrane is
mostly composed of type IV collagen, which resembles the human
epithelium basement membrane [52–57]. Our results show that the
promising antiproliferative synthesized agents 6a–c and 10a–c possess
anti-angiogenic properties as they can decrease the number and diam-
eter of the blood vessels with potency comparable to that of Sunitinib,
which is a well-known drug with anti-angiogenic properties [69–71]. In
conclusion, the synthesized agents 6 and 10 can be considered as po-
tential anti-tumor agents with anti-angiogenic properties.
2.3.4. Cell cycle study
Cell cycle analysis via quantitative DNA content is an important
technique capable to identify the proliferation of culture cells and cell
distribution in each phase of the cell cycle. Propidium iodide (PI)
6

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Fig. 5. (A) Images and histology using H&E
of the chick embryo chorioallantoic mem-
brane (CAM) for vehicle control, positive
control (Sunitinib) and test compounds. At
day 8, eggs were opened carefully. Twenty
μ
l of control vehicle or test compounds (final
concentration of 660 M) were left to dry on
μ
a 2.5 cm round glass slide on the surface of
the CAM blood network. Eggs were covered
◦
and left in an incubator at 37 C for 3 days.
Later the membrane around the area of in-
terest was fixed with 5% formalin, and
paraffin embedded for further staining.
Original images were done at 40x and 100x
magnification “CM: chorionic membrane.
ML: mesodermal layer. BV: blood vessel”.
(
B) Quantitative analysis of blood vessel
diameter in mm after 3 days of treatment.
Sunitinib (positive control) and test com-
pounds all show significant reduction in BV
diameters. All results are expressed as mean
±
SD (n = 4) (***P < 0.001 in comparison
to control).
7

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Table 2
in S phase
Blood vessel diameter of tested compound and Sunitinib.
than that of the control experiment” (%S = 54.18, 41.12 for com-
pound 10b and control experiment, respectively). This supports the ef-
ficacy of compound 10b to arrest the tested cell at S phase.
Entry
Compd.
Mean diameter of blood vessels (mm ± SD “standard
division”)
Apoptosis induction [86] was also noticed by the bio-active agents
synthesized 6b and 10b against MCF7 cell utilizing IC50 values discov-
ered (Table 1). From the results obtained (Table 5, Fig. 8) it has been
noticed that compound 6b is a higher apoptosis performing agent than
1
2
3
4
5
6
7
8
Control
Sunitinib
6a
14.00 ± 3.00
5.00 ± 0.71
3.20 ± 1.00
5.10 ± 1.00
5.13 ± 0.90
3.50 ± 0.50
2.70 ± 0.40
5.00 ± 0.40
6b
6c
1
0b. This is due to the increased late stage of apoptosis observed by 6b
10a
than 10b (% late stage = 22.91, 17.15 by compounds 6b and 10b,
respectively). Compound 6b also reveals higher necrosis induction than
10b
10c
1
0b (% necrosis = 9.29, 7.07 by compounds 6b and 10b, respectively).
2
.3.5. Antiviral properties
Table 3
Kinase inhibitory properties of the promising antiproliferative 3-alkenyl-2-oxin-
Antiviral properties of the synthesized 3-alkenyl-2-oxindoles (6a–c,
doles (6a–c, 10a–c) synthesized and Sunitinib.
10a–c) against SARS-CoV-2 were determined by the standard technique
[
87–89] and compared with that of hydroxychloroquine, chloroquine
Entry
Compd.
IC50 (nM ± SD)
and Favipiravir, which are used as standard references. Table 6 (Fig. 9)
reveals the IC50 (concentration needed for 50% reduction of virus-
induced cytopathic effect compared to control experiment) and the
CC50 (concentration needed for 50% growth normal cell line “VERO-E6,
needed for viral growth” inhibition relative to control experiment) for
all the tested compounds. The SI (therapeutical/selectivity index, which
is the ratio of CC50 relative to IC50) is an important parameter identifying
the selectivity of the tested agent for the viral cell relative to the host
normal cell. This is an important indicator explaining the safety profile
of a tested agent.
VEGFR-2
c-kit
1
2
3
4
5
6
7
6a
54.03 ± 5.4
98.95 ± 9.9
36.86 ± 3.7
102.2 ± 10.2
74.06 ± 7.4
53.36 ± 5.3
47.54 ± 4.8
119.8 ± 12.0
247.7 ± 24.8
72.35 ± 7.2
103.3 ± 10.3
184.9 ± 18.5
81.7 ± 8.2
6b
6c
10a
10b
10c
Sunitinib
84.9 ± 8.5
staining of DNA utilizing flow cytometry cell cycle analysis is an
accessible technique for stoichiometric DNA cell content determination
From the observed results, it can be concluded that many of the
synthesized agents reveal antiviral properties with potency high than
that of hydroxychloroquine (which reveals higher potency relative to
the other standard references used, chloroquine and Favipiravir).
[
84]. Arresting cell cycle during the transition from G1 phase to S phase
seems an important mode for many antiproliferative active agents [85].
Compounds 6b and 10b (the most effective antiproliferation agents
synthesized against breast cancer cell line) were subjected for induced
cell cycle study of MCF7 utilizing the assigned IC50 value (Table 1). This
identifies the cell cycle distribution and phase arresting during the
antiproliferation inhibitory process of the bio-active agents. From the
results obtained (Table 4, Figs. 7, 8) it has been noticed that, compound
Compounds 10b and 6a are superior among all the tested agents (IC50
=
3
.417, 3.799 µM, for 10b and 6a, respectively). However, compound 6a
seems a preferable agent than 10b for any higher biological testing due
to the higher SI revealed (SI = 362.5, 165.6 for 6a and 10b,
6
b reveals decrease in the accumulated tested cells at G2/M relative to
Table 4
the control experiment (% G2/M = 2.67, 5.09 for compound 6b and
control experiment, respectively; i.e. 47.5% decrease in cell population).
However, slight accumulation of the tested cell at G1/S phase was
observed relative to the control (%G0-G1 = 54.08, 53.79; %S = 43.25,
Percentage cell distribution during induced cell cycle study for compounds 6b
and 10b on MCF7 cells by PI-flow cytometry.
Entry
Compd.
DNA content (%)
4
1.12 for compound 6b and control experiment, respectively). This
G0-G1
S
G2/M
Pre-G1
identifies that compound 6b arrests the cell cycle at G1/S phase. On the
other hand, compound 10b reveals accumulation of the tested cell at S
phase higher than that of G0/G1 phase “also with about 13% increment
1
2
3
6a
54.08
41.71
53.79
43.25
54.18
41.12
2.67
4.11
5.09
34.71
28.25
1.49
10a
Control
275
250
225
200
175
150
125
100
VEGFR-2
c-kit
75
50
25
0
6a
6b
6c
10a
10b
10c
Sunitinib
Compounds tested
Fig. 6. Kinase inhibitory properties of the tested compounds and Sunitinib.
8

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
60
50
40
30
20
10
0
G0-G1
S
G2/M
Pre-G1
6a
10a
Control
Compounds tested
Fig. 7. DNA content during induced cell cycle analysis study (MCF7) for the tested compounds and control experiment by PI-flow cytometry.
respectively). Compound 6c is also a promising agent with enhanced
potency and selectivity index than the standard references used (IC50
alignment in the protein active site through
π
- interaction taking place
σ
=
between the indolyl heterocycle and VAL603. Again, the sigh compati-
bility differences observed due to docking scores and c-kit kinase
inhibitory properties of the tested analogues can be attributed to the
experimental conditions applied for the biochemical testing which are
not considered in the computational work Table 7 (Supplementary
Fig. S118).
1
3.52, 29.25, 19.78; SI = 26.4, 12.2, 19.1 for 6c, hydroxychloroquine
and chloroquine, respectively). Compound 10c exhibits promising SI
due to its high cytotoxicity value
(
CC50) relative to the antiviral potency (IC50) value (IC50 = 20.1,
CC50 = 1517 µM, SI = 75.5).
Generally, the docking studies especially, alignment and hydrogen
bonding revealed by the docked agents in the protein active sites, sup-
port the multi-targeted kinase inhibitory properties of 6a–c and 10a–c in
a comparable behavior to that known by Sunitinib.
2
.4. Molecular modeling
Molecular modeling is a computational technique intensively uti-
lized in medicinal chemical studies. It is useful for identifying the pa-
rameters necessary for bio-properties via exploring the interaction
taking place between the proposed bio-active agent and amino acids of
the protein active site. This may support the assumed mode of action and
assigning the agent’s functional group(s) necessary for the observed
biological properties. Standard CDOCKER technique was considered in
the current study (Discovery Studio 2.5 software; force field, CHARMm;
partial charge method, MMFF94) utilizing PDB ID: 4AGD, 3G0E for
VEGFR-2 and c-kit modeling respectively [90–93]. Table 7 (Supple-
mentary Figs. S117, S118) exhibits the molecular docking results for the
promising antiproliferative agents synthesis (6a–c, 10a–c) and Sunitinib
3. Conclusion
In conclusion, 3-alkenyl-2-oxindoles with sulfonate or sulfonamide
function seem promising antiproliferative agents. Compounds 6c and
10b are the most effective agents synthesized (about 3.4, 3.3 folds,
respectively) against PaCa2 (pancreatic) cancer cell line relative to
Sunitinib. Additionally, compound 10b reveals antiproliferative prop-
erties against MCF7 (breast) cancer cell line with IC50 close to that of the
standard. Meanwhile, compound 6c is the only synthesized analog with
cytotoxic properties against HCT116 (colon cancer) cell line close to the
standard reference used. CAM testing reveals that compounds 6 and 10
are capable to reduce blood vessel diameter with efficacy comparable to
that of Sunitinib supporting their anti-angiogenic properties. Kinase
inhibitory properties of the promising antiproliferative 3-alkenyl-2-
oxindoles (6a–c, 10a–c) synthesized support their multi-targeted
inhibitory activities against VEGFR-2 and c-kit in similar behavior to
that of Sunitinib. Molecular docking studies (PDB ID: 4AGD and 3G0E)
support these observations. Cell cycle analysis studies utilizing MCF7
(breast) cancer cell, exhibit that compound 6b arrests the cell cycle at
G1/S phase while, 10b reveals accumulation of the tested cell at S phase.
Additionally, compound 6b is a higher apoptosis performing agent than
10b. Compounds 6a and 10b reveal potent antiviral properties against
SARS-CoV-2 with high therapeutical/selectivity index relative to all the
standards used (hydroxychloroquine, chloroquine and Favipiravir). The
safety profile of the testing agents, especially the high potent ones,
against normal cells (VERO-E6 and RPE1) is a good indication for the
possibility of utilization as antitumor and/or antiviral agents. Also, the
promising results obtained can be adopted for developing higher effec-
tive hits.
(
reference standard used) in the PDB ID: 4AGD and 3G0E responsible for
VEGFR-2 and c-kit inhibition, respectively.
2
.4.1. VEGFR-2
Table 7 (Supplementary Fig. 117) reveals that, all the tested com-
pounds aligned perfectly in the active site of the used protein in a similar
manner/behavior to that of Sunitinib with different docking scores. All
the tested compounds give hydrogen bonding interaction between the
–
indolyl C O and CYS919 of the protein active site. Additionally, com-
–
pounds 6b and 10a-c reveal hydrogen bonding interaction of the indolyl
NH with the GLU917 of the protein active site, which is also shown by
Sunitinib (co-crystallized ligand in the protein active site). -Interaction
π
is only revealed by compound 6a. The minor docking score compati-
bility difference of the docked agents relative to the kinase inhibitory
properties observed (Table 3) can be attributed to the effect of envi-
ronmental conditions applied in the kinase investigation experimental
technique, which are not considered in the computational studies.
2
.4.2. c-Kit
All the tested compounds (6a–c, 10a–c) show two hydrogen-bonding
interactions with CYS673 and GLU671 of the protein active site with
alignment similar to that of Sunitinib and varied docking scores. Addi-
tionally, all the tested compounds (10b is an exception) support their
9

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Fig. 8. Cell cycle analysis and apoptosis induced by the tested compounds and control experiment for MCF7.
4
. Experimental
mm silica gel F254 plates (Merck) utilizing various solvents for elution.
The chemical structures of the synthesized compounds were character-
1
13
4
.1. Chemistry
ized by nuclear magnetic resonance spectra ( H NMR, C NMR) and
1
determined on a Bruker NMR spectrometer (500 MHz, 125 MHz for H
and 13C, respectively). C NMR spectra are fully decoupled. Chemical
shifts were reported in parts per million (ppm) using the deuterated
solvent peak or tetramethylsilane as an internal standard.
13
Melting points were determined on a capillary point apparatus
(
Stuart SMP3) equipped with a digital thermometer. IR spectra (KBr)
were recorded on a Shimadzu FT-IR 8400S spectrophotometer. Re-
actions were monitored using thin layer chromatography (TLC) on 0.2
1
0

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Table 5
hydroxyacetophenone 1 in methylene chloride (20 ml) containing trie-
thylamine (5.5 mmol) at 0–5 ◦C. After complete addition, the reaction
with stirred at the same conditions for 3 h and stored at room temper-
ature (20–25 ◦C) overnight. The reaction mixture was washed with
Percentage apoptosis and necrosis for compounds 6b and 10b on MCF7 cells
induced by IC50 values.
Entry
Compd.
Apoptosis (%)
Total
Necrosis
concentrated solution of NaHCO
3
(3 × 20 ml) then, with water. The solid
Early
Late
separated upon evaporating the reaction mixture till dryness under
reduced pressure, was crystallized from methanol affording the corre-
sponding 3a,b as colorless crystals.
1
2
3
6b
34.71
28.25
1.49
2.51
4.03
0.49
22.91
17.15
0.13
9.29
7.07
0.87
10b
Control
4
.1.1.1. 4-Acetylphenyl methanesulfonate (3a) [94]. It was obtained
◦
from the reaction of 1 and 2a with mp 72–74 C and yield 98% (1.05 g).
Table 6
ꢀ
1
1
IR:
H, H
d, J = 8.7 Hz, 2H, arom. H). C NMR (DMSO‑d
CCO), 37.7 (H CS), 122.3, 130.3, 135.5, 152.3 (arom. C), 196.8
CO). Anal. Calcd. for C S (214.24): C, 50.46; H, 4.71. Found: C,
ν
max/cm 1682, 1597, 1501. H NMR (DMSO‑d
6
) δ (ppm): 2.61 (s,
Antiviral properties of the tested compounds against SARS-CoV-2.
3
3
CCO), 3.47 (s, 3H, H
3
CS), 7.50 (d, J = 8.7 Hz, 2H, arom. H), 8.08
a
b
c
Entry
Compd.
IC50 (µM)
CC50 (µM)
SI
13
(
(
(
6
) δ (ppm): 26.7
1
2
3
4
5
6
7
8
9
6a
3.799
55.14
13.52
219
1377
1313
356.9
1617
566
362.5
23.8
26.4
7.4
H
3
3
6b
9 10 4
H O
6c
5
0.65; H, 4.85.
10a
10b
3.417
20.1
165.6
75.5
12.2
19.1
1.9
10c
1517
356.4
377.7
2633
4
.1.1.2. 4-Acetylphenyl ethanesulfonate (3b). It was obtained from the
Hydroxychloroquine
Chloroquine
Favipiravir
29.25
19.78
1382
◦
reaction of 1 and 2b with mp 63–65 C and yield 89% (1.02 g). IR:
ν
max
/
cm 1678, 1593, 1497. 1H NMR (DMSO‑d
Hz, 3H, H CH CS), 2.60 (s, 3H, H
CCO), 3.60 (q, J = 7.4 Hz, 2H, H
.48 (d, J = 8.7 Hz, 2H, arom. H), 8.07 (d, J = 8.7 Hz, 2H, arom. H).
NMR (DMSO‑d ) δ (ppm): 8.0 (H CH CS), 26.7 (H CCO), 45.1 (H CS),
22.2, 130.4, 135.5, 152.2 (arom. C), 196.8 (CO). Anal. Calcd. for
S (228.26): C, 52.62; H, 5.30. Found: C, 52.73; H, 5.46.
ꢀ 1
) δ (ppm): 1.41 (t, J = 7.4
6
3
2
3
2
CS),
a
CC50 = Cytotoxic concentration due to 50% growth compared to the control
13
7
C
experiment.
b
6
3
2
3
2
IC50 = Inhibitory concentration due to 50% growth compared to the control
1
experiment.
10 12 4
C H O
CC50
c
SI (Selectivity index/therapeutical index) = IC50
4
.1.2. Reaction of 3a,b with 4a,b (general procedure)
A mixture of equimolar amounts of the appropriate isatin 4a,b (5
4
.1.1. Reaction of 4-hydroxyacetophenone (1) and alkane sulfonylchloride
2
a,b (general procedure)
mmol) and the corresponding acetophenone 3a,b in ethanol absolute
(15 ml) containing quantitative amount of diethylamine was stirred at
room temperature (20–25 ◦C) for the appropriate time. The separated
solid 5a-d was collected washed with benzene (10 ml) and used in the
A solution of equimolar amounts of the appropriate alkane sulfo-
nylchlorides 2a,b (5 mmol) in dry methylene chloride (5 ml) was added
dropwise (10 min.) to the magnetically stirred solution of 4-
Fig. 9. Dose-response curves for the tested compounds against SARS-CoV-2.
1
1

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
Table 7
4.1.2.2. 4-[2-(5-Chloro-3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl meth-
Molecular modeling results due to docking of compounds (6a–c, 10a–c) and
Sunitinib in the PDB ID: 4AGD and 3G0E responsible for VEGFR-2 and c-kit
inhibitors, respectively.
anesulfonate (5b). It was obtained from the reaction of 3a and 4b as
◦
colorless solid, reaction time 24 h, with mp 195–197 C and yield 92%
ꢀ 1
1
(
1.82 g). IR:
(ppm): 3.45 (s, 3H, SCH
.18 (d, J = 17.9 Hz, 1H, downfield H of CH
(d, J = 8.3 Hz, 1H, arom. H), 7.23 (dd, J = 2.0, 8.2 Hz, 1H, arom. H),
.41 (d, J = 1.8 Hz, 1H, arom. H), 7.49 (d, J = 8.6 Hz, 2H, arom. H), 8.03
ν
max/cm 3217, 1697, 1625, 1597. H NMR (DMSO‑d
6
) δ
CO),
2
CO), 6.26 (s, 1H, OH), 6.85
Entry
Compd.
PDB ID: 4AGD
PDB ID: 3G0E
3
), 3.67 (d, J = 17.9 Hz, 1H upfield H of CH
2
4
Docking
Docking
Docking
Docking
a
a
score
observations
score
observations
7
1
6a
ꢀ 31.48
H-bond:
ꢀ 50.99
H-bond: indolyl
CO - CYS673,
indolyl NH -
1
3
(
d, J = 8.7 Hz, 2H, arom. H), 10.44 (s, 1H, NH). C NMR (DMSO‑d
(ppm): 37.6 (SCH ), 45.7 (CH CO), 73.0 (indolyl C-3), 110.8, 122.3,
23.9, 125.1, 128.6, 130.2, 133.7, 134.6, 141.8, 152.5 (arom. C), 177.9
indolyl CO (C-2)], 195.5 (ketonic CO). Anal. Calcd. for C17 14ClNO
395.81): C, 51.59; H, 3.57; N, 3.54. Found: C, 51.79; H, 3.72; N, 3.70.
6
) δ
indolyl CO -
CYS919;
π
-
σ
3
2
interactions:
indole -
GLU671, sulfonyl
1
SO-ASP677;
π-σ
[
H
6
S
VAL848
interactions:
(
indole–VAL603
H-bond: indolyl
CO - CYS673,
indolyl NH -
2
3
6b
6c
ꢀ 40.07
ꢀ 35.67
H-bond:
ꢀ 50.69
ꢀ 56.56
indolyl CO -
CYS919,
4
.1.2.3. 4-[2-(3-Hydroxy-2-oxoindolin-3-yl)acetyl]phenyl ethanesulfonate
(
5c). It was obtained from the reaction of 3b and 4a as colorless solid,
indolyl NH -
GLU917
GLU671;
π σ
-
◦
reaction time 24 h, with mp 156–158 C and yield 80% (1.50 g). IR:
interactions:
ꢀ 1
1
indole–VAL603
H-bond: indolyl
CO - CYS673,
indolyl NH -
ν
max/cm 3306, 1709, 1678, 1618, 1601. H NMR (DMSO‑d
CH
CS), 3.58 (q, J = 7.1 Hz, 2H, SCH
CO), 4.09 (d, J = 17.5 Hz, 1H,
6
) δ (ppm):
H-bond:
1.38 (t, J = 7.1 Hz, 3H, H
2
), 3.61
3
2
indolyl CO -
CYS919
(
d, J = 17.2 Hz, 1H upfield H of CH
2
downfield H of CH
2
CO), 6.12 (s, 1H, OH), 6.83 (d, J = 7.6 Hz, 1H, arom.
GLU671;
π σ
-
H), 6.87 (t, J = 7.4 Hz, 1H, arom. H), 7.17 (t, J = 7.4 Hz, 1H, arom. H),
7.29 (d, J = 7.1 Hz, 1H, arom. H), 7.45 (d, J = 8.2 Hz, 2H, arom. H), 8.02
interactions:
indole–VAL603,
phenyl-LEU595
H-bond: indolyl
CO - CYS673,
indolyl NH -
1
3
(
d, J = 8.3 Hz, 2H, arom. H), 10.30 (s, 1H, NH). C NMR (DMSO‑d
6
) δ
CO), 73.1 (indolyl C-3),
09.6, 121.3, 122.4, 123.7, 129.1, 130.3, 131.7, 134.9, 143.0, 152.4
(arom. C), 178.4 [indolyl CO (C-2)], 195.5 (ketonic CO). Anal. Calcd. for
17NO S (375.40): C, 57.59; H, 4.56; N, 3.73. Found: C, 57.47; H,
.75; N, 3.84.
4
10a
ꢀ 34.67
H-bond:
ꢀ 57.88
(
3 2 2 2
ppm): 8.1 (H CH CS), 45.1 (SCH ), 45.9 (CH
indolyl CO -
CYS919,
1
indolyl NH -
GLU917
GLU671,
sulfonamide SO-
C
H
18
6
ASP677;
π σ
-
4
interactions:
indole–VAL603
H-bond: indolyl
CO - CYS673
5
6
10b
10c
ꢀ 39.46
–33.29
H-bond:
ꢀ 55.81
ꢀ 58.33
4.1.2.4. 4-[2-(5-Chloro-3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl etha-
indolyl CO -
CYS919,
nesulfonate (5d). It was obtained from the reaction of 3b and 4b as
◦
colorless solid, reaction time 24 h, with mp 171–173 C and yield 86%
indolyl NH -
GLU917
ꢀ 1
1
(
(
1.75 g). IR:
DMSO‑d
ν
max/cm
3244, 1701, 1690, 1620, 1597. H NMR
6
) δ (ppm): 1.39 (t, J = 7.3 Hz, 3H, H
), 3.68 (d, J = 17.9 Hz, 1H upfield H of CH
17.9 Hz, 1H, downfield H of CH
CO), 6.27 (s, 1H, OH), 6.86 (d, J =
.3 Hz, 1H, arom. H), 7.24 (dd, J = 2.1, 8.3 Hz, 1H, arom. H), 7.42 (d, J
2.0 Hz, 1H, arom. H), 7.47 (d, J = 8.7 Hz, 2H, arom. H), 8.03 (d, J =
3
CH
2
CS), 3.59 (q, J = 7.3
H-bond:
H-bond: indolyl
CO - CYS673,
indolyl NH -
GLU671,
indolyl CO -
CYS919,
Hz, 2H, SCH
2
2
CO), 4.19 (d, J
=
2
indolyl NH -
GLU917
8
sulfonamide SO-
ASP677
=
1
3
7
Sunitinib
ꢀ 53.64
H-bond:
ꢀ 59.88
H-bond: indolyl
CO - CYS673,
indolyl NH -
8.7 Hz, 2H, arom. H), 10.45 (s, 1H, NH). C NMR (DMSO‑d
8.0 (H CH CS), 45.0 (SCH ), 45.7 (CH CO), 73.0 (indolyl C-3), 110.8,
22.2, 124.0, 125.2, 128.6, 130.2, 133.8, 134.5, 141.8, 152.4 (arom. C),
77.9 [indolyl CO (C-2)], 195.4 (ketonic CO). Anal. Calcd. for
16ClNO S (409.84): C, 52.75; H, 3.94; N, 3.42. Found: C, 52.88; H,
.14; N, 3.54.
6
) δ (ppm):
indolyl CO -
CYS919,
3
2
2
2
1
1
indolyl NH -
GLU917
GLU671;
π σ
-
interactions:
C
18
H
6
indole–VAL603
4
a
ꢀ 1
.
Docking score in kcal mol
next step without any more purification.
.1.2.1. 4-[2-(3-Hydroxy-2-oxoindolin-3-yl)acetyl]phenyl methanesulfo-
4
.1.3. Acidic dehydration of 5 (general procedure)
Hydrochloric acid (25 ml, 25%) was added dropwise (10 min.) to a
magnetically stirred solution of 5 (5 mmol) in absolute ethanol (12.5 ml)
4
◦
at room temperature (20–25 C) for the appropriate time. The separated
nate (5a). It was obtained from the reaction of 3a and 4a as colorless
solid was collected, washed with water and purified by crystallization
from a suitable solvent affording the corresponding 6a,b; and chro-
matographic tool (silica gel TLC) giving 6c.
◦
solid, reaction time 48 h, with mp 159–161 C and yield 73% (1.31 g).
max/cm 3291, 1701, 1675, 1616, 1601. 1H NMR (DMSO‑d
ꢀ
1
) δ
CO),
2
CO), 6.11 (s, 1H, OH), 6.82
IR:
ppm): 3.44 (s, 3H, SCH
.09 (d, J = 17.5 Hz, 1H, downfield H of CH
d, J = 7.7 Hz, 1H, arom. H), 6.87 (t, J = 7.4 Hz, 1H, arom. H), 7.17 (t, J
7.6 Hz, 1H, arom. H), 7.29 (d, J = 7.3 Hz, 1H, arom. H), 7.47 (d, J =
.7 Hz, 2H, arom. H), 8.02 (d, J = 8.7 Hz, 2H, arom. H), 10.29 (s, 1H,
ν
6
(
3
), 3.61 (d, J = 17.5 Hz, 1H upfield H of CH
2
4
4
.1.3.1. (E)-4-[2-(2-Oxoindolin-3-ylidene)acetyl]phenyl methanesulfonate
(
(
6a). It was obtained from acidic dehydration of 5a for 72 h as red
=
◦
microcrystals from n-butanol with mp 222–224 C and yield 86% (1.47
g). IR:
8
ꢀ 1
1
ν
max/cm 3352, 1721, 1659, 1601. H NMR (DMSO‑d
.51 (s, 3H, SCH
), 6.91 (d, J = 7.8 Hz, 1H, arom. H), 6.98 (t, J = 7.7 Hz,
H, arom. H), 7.37 (t, J = 7.7 Hz, 1H, arom. H), 7.59 (d, J = 8.6 Hz, 2H,
6
) δ (ppm):
1
3
NH). C NMR (DMSO‑d
6
) δ (ppm): 37.6 (SCH
3 2
), 45.7 (CH CO), 72.9
3
1
3
(
indolyl C-3), 109.3, 121.1, 122.3, 123.5, 128.9, 130.1, 131.5, 134.8,
1
42.8, 152.4 (arom. C), 178.2 [indolyl CO (C-2)], 195.4 (ketonic CO).
15NO S (361.37): C, 56.50; H, 4.18; N, 3.88. Found:
C, 56.59; H, 4.31; N, 4.02.
arom. H), 7.74 (s, 1H, olefinic CH), 8.09 (d, J = 7.7 Hz, 1H, arom. H),
Anal. Calcd. for C17
H
6
13
8
.21 (d, J = 8.6 Hz, 2H, arom. H), 10.83 (s, 1H, NH). C NMR
DMSO‑d ) δ (ppm): 37.8 (SCH ), 110.3, 119.9, 121.7, 122.8, 125.3,
26.8, 130.8, 133.1, 135.8, 136.8, 145.0, 152.7 (arom. C), 168.1
13NO
(
6
3
1
[
indolyl CO (C-2)], 190.0 (ketonic CO). Anal. Calcd. for C17
H
5
S
1
2

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
(
343.35): C, 59.47; H, 3.82; N, 4.08. Found: C, 59.29; H, 3.66 N, 3.95.
.1.3.2. (E)-4-[2-(2-Oxoindolin-3-ylidene)acetyl]phenyl ethanesulfonate
4.1.4.3. N-(4-Acetylphenyl)propane-1-sulfonamide (8c). It was obtained
from the reaction of 7 and 2c as colorless microcrystals from methanol
◦
ꢀ 1
4
with mp 125–127 C and yield 92% (1.11 g). IR:
ν
max/cm 3252, 3213,
1
(
6b). It was obtained from acidic dehydration of 5c for 72 h as red
1670, 1601, 1578. H NMR (DMSO‑d
6
) δ (ppm): 0.94 (t, J = 7.5 Hz, 3H,
CH CS), 2.52 (s, 3H,
), 7.30 (d, J = 8.7 Hz, 2H, arom.
◦
microcrystals from methanol with mp 166–170 C and yield 75% (1.34
g). IR:
H
3
CH
2
CH
2
CS), 1.69 (sextet, J = 7.4 Hz, 2H, H
2
2
ꢀ
1
1
ν
max/cm 3159, 1713, 1659, 1620. H NMR (DMSO‑d
6
) δ (ppm):
H
3
CCO), 3.18 (t, J = 7.6 Hz, 2H, SCH
2
1
3
1
7
.41 (t, J = 7.3 Hz, 3H, CH ), 3.63 (q, J = 7.4 Hz, 2H, SCH ), 6.90 (d, J =
3
2
H), 7.93 (d, J = 8.7 Hz, 2H, arom. H), 10.33 (s, 1H, NH). C NMR
(DMSO‑d ) δ (ppm): 12.4 (H CH CH CS), 16.8 (H CH CS), 26.3
(H CCO), 52.8 (SCH ), 117.3, 129.9, 131.5, 143.0 (arom. C), 196.4
(CO). Anal. Calcd. for C11 15NO S (241.31): C, 54.75; H, 6.27; N, 5.80.
Found: C, 54.58; H, 6.46; N, 5.74.
.8 Hz, 1H, arom. H), 6.97 (t, J = 7.7 Hz, 1H, arom. H), 7.36 (t, J = 7.7
6
3
2
2
2
2
Hz, 1H, arom. H), 7.55 (d, J = 8.8 Hz, 2H, arom. H), 7.72 (s, 1H, olefinic
CH), 8.07 (d, J = 7.8 Hz, 1H, arom. H), 8.20 (d, J = 8.7 Hz, 2H, arom. H),
3
2
H
3
1
1
1
0.82 (s, 1H, NH). 13C NMR (DMSO‑d
6 3 2
) δ (ppm): 8.0 (CH ), 45.1 (SCH ),
10.3, 119.8, 121.7, 122.6, 125.3, 126.8, 130.8, 133.0, 135.7, 136.7,
45.0, 152.6 (arom. C), 168.1 [indolyl CO (C-2)], 189.9 (ketonic CO).
4.1.5. Reaction of 8a-c with 4a-c (general procedure)
Anal. Calcd. for C18
H
15NO
5
S (357.38): C, 60.50; H, 4.23; N, 3.92. Found:
A mixture of equimolar amounts of the appropriate isatin 4a-c (5
mmol) and the corresponding acetophenone 8a-c in ethanol absolute
C, 60.39H, 4.31; N, 3.73.
(
15 ml) containing quantitative amount of diethylamine was stirred at
room temperature (20–25 ◦C) for the appropriate time. The separated
solid 9a–g was collected washed with benzene (10 ml) and used in the
next step without any more purification.
4
.1.3.3. (E)-4-[2-(5-Chloro-2-oxoindolin-3-ylidene)acetyl]phenyl ethane-
sulfonate (6c). It was obtained from acidic dehydration of 5d for 72 h as
red microcrystals purified by silica gel TLC (60 G, F254 glass plate) using
◦
CH
2
Cl
2
for elution, with mp 180–182 C and yield 77% (1.51 g). IR:
ꢀ
1
1
ν
max/cm 3179, 1713, 1659, 1601. H NMR (DMSO‑d
t, J = 7.3 Hz, 3H, CH ), 3.64 (q, J = 7.3 Hz, 2H, SCH ), 6.91 (d, J = 8.3
Hz, 1H, arom. H), 7.42 (dd, J = 2.1, 8.3 Hz, 1H, arom. H), 7.56 (d, J =
.7 Hz, 2H, arom. H), 7.80 (s, 1H, olefinic CH), 8.17 (d, J = 1.9 Hz, 1H,
6
) δ (ppm): 1.41
4.1.5.1. N-{4-[2-(3-Hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-N-(meth-
(
3
2
ylsulfonyl)methanesulfonamide (9a). It was obtained from the reaction of
◦
8a and 4a as colorless solid, reaction time 48 h, with mp 209–211 C and
ꢀ
1
1
8
yield 72% (1.57 g). IR:
NMR (DMSO‑d
upfield H of CH
ν
max/cm 3410, 1701, 1682, 1620, 1601. H
1
3
arom. H), 8.21 (d, J = 8.7 Hz, 2H, arom. H), 10.96 (s, 1H, NH). C NMR
DMSO‑d ) δ (ppm): 8.0 (CH ), 45.1 (SCH ), 111.8, 121.3, 122.6, 125.5,
26.4, 131.0, 132.5, 135.6, 136.2, 143.9, 152.7 (arom. C), 167.8
indolyl CO (C-2)], 189.5 (ketonic CO). Anal. Calcd. for C18 14ClNO
391.82): C, 55.18; H, 3.60; N, 3.57. Found: C, 55.33; H, 3.73; N, 3.51.
6
) δ (ppm): 3.56 (s, 6H, 2 SCH
3
), 3.63 (d, J = 17.6 Hz, 1H
(
6
3
2
2
CO), 4.11 (d, J = 17.6 Hz, 1H, downfield H of CH
2
CO),
1
6.10 (s, 1H, OH), 6.82 (d, J = 7.7 Hz, 1H, arom. H), 6.86 (t, J = 7.5 Hz,
1H, arom. H), 7.17 (t, J = 7.7 Hz, 1H, arom. H), 7.29 (d, J = 7.3 Hz, 1H,
arom. H), 7.66 (d, J = 8.4 Hz, 2H, arom. H), 7.99 (d, J = 8.4 Hz, 2H,
[
H
5
S
(
arom. H), 10.29 (s, 1H, NH). 13C NMR (DMSO‑d
6
3
) δ (ppm): 43.0 (SCH ),
4
.1.4. Reaction of 4-aminoacetophenone (7) and alkane sulfonylchloride
45.8 (CH
131.2, 131.5, 137.0, 137.9, 142.8 (arom. C), 178.1 [indolyl CO (C-2)],
195.8 (ketonic CO). Anal. Calcd. for C18 (438.47): C, 49.31;
H, 4.14; N, 6.39. Found: C, 49.51; H, 4.28; N, 6.55.
2
CO), 72.9 (indolyl C-3), 109.3, 121.1, 123.6, 128.9, 129.0,
2
a-c (general procedure)
A solution of the appropriate alkane sulfonylchlorides 2a-c (10 mmol
18 2 7 2
H N O S
in case of 2a,b and 5 mmol in case of 2c) in dry methylene chloride (5
ml) was added dropwise (10 min.) to the magnetically stirred solution of
4
-aminoacetophenone 7 (5 mmol) in methylene chloride (20 ml) con-
4.1.5.2. N-{4-[2-(5-Chloro-3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-
taining triethylamine (11 mmol in case of 2a,b and 5.5 mmol in case of
N-(methylsulfonyl)methanesulfonamide (9b). It was obtained from the
◦
2
c) at 0–5 C. After complete addition, the reaction with stirred at the
reaction of 8a and 4b as colorless solid, reaction time 72 h, with mp
◦
208–210 ◦C and yield 69% (1.64 g). IR:
ꢀ 1
same conditions for 3 h and stored at room temperature (20–25 C)
ν
max/cm 3337, 1724, 1694,
1
overnight. The reaction mixture was washed with concentrated solution
1621, 1601. H NMR (DMSO‑d
6
) δ (ppm): 3.57 (s, 6H, 2 SCH
3
), 3.70 (d,
of NaHCO
3
(3 × 20 ml) then, with water. The solid separated upon
J = 18.0 Hz, 1H upfield H of CH
downfield H of CH
2
CO), 4.21 (d, J = 18.1 Hz, 1H,
evaporation the reaction mixture till dryness under reduced pressure,
was collected and crystallized from a suitable solvent affording the
corresponding 8a-c as colorless crystals.
2
CO), 6.26 (s, 1H, OH), 6.85 (d, J = 8.3 Hz, 1H, arom.
H), 7.24 (dd, J = 2.1, 8.3 Hz, 1H, arom. H), 7.42 (d, J = 2.1 Hz, 1H,
arom. H), 7.69 (d, J = 8.5 Hz, 2H, arom. H), 8.00 (d, J = 8.5 Hz, 2H,
arom. H), 10.44 (s, 1H, NH). 13C NMR (DMSO‑d
6
3
) δ (ppm): 43.1 (SCH ),
4
.1.4.1. N-(4-Acetylphenyl)-N-(methylsulfonyl)methanesulfonamide
45.7 (CH
129.0, 129.7, 131.2, 133.7, 136.8, 138.0, 141.8 (arom. C), 177.9
[indolyl CO (C-2)], 195.9 (ketonic CO). Anal. Calcd. for C18 17ClN
2
CO), 72.9 (indolyl C-3), 110.7, 117.3, 123.9, 125.1, 128.6,
(
8a). It was obtained from the reaction of 7 and 2a as colorless mi-
◦
crocrystals from n-butanol with mp 172–174 C and yield 82% (1.20 g).
H
2 7 2
O S
ꢀ 1
1
IR:
ν
max/cm 1682, 1597, 1504. H NMR (DMSO‑d
H, H CCO), 3.57 (s, 6H, 2 SCH
), 7.69 (d, J = 8.5 Hz, 2H, arom. H),
.04 (d, J = 8.4 Hz, 2H, arom. H). C NMR (DMSO‑d
CCO), 43.1 (H CS), 129.1, 131.2, 137.7 (arom. C), 197.2 (CO). Anal.
Calcd. for C10 13NO (291.34): C, 41.23; H, 4.50; N, 4.81. Found: C,
1.13; H, 4.43; N, 4.66.
6
) δ (ppm): 2.63 (s,
(472.91): C, 45.72; H, 3.62; N, 5.92. Found: C, 45.81; H, 3.78; N, 6.06.
3
8
3
3
1
3
6
) δ (ppm): 26.9
4.1.5.3. N-(Ethylsulfonyl)-N-{4-[2-(3-hydroxy-2-oxoindolin-3-yl)acetyl]
(
H
3
3
phenyl}ethanesulfonamide (9c). It was obtained from the reaction of 8b
◦
H
5
S
2
and 4a as colorless solid, reaction time 48 h, with mp 204–206 C and
ꢀ 1
4
yield 67% (1.56 g). IR: max/cm 3402, 3198, 1697, 1682, 1620, 1601.
ν
1
H NMR (DMSO‑d
6
) δ (ppm): 1.34 (t, J = 7.3 Hz, 6H, 2 CH
CO), 3.68 (q, J = 7.4 Hz, 4H, 2 SCH
CO), 6.12 (s, 1H, OH), 6.84 (d, J
3
), 3.63 (d, J =
4
.1.4.2. N-(4-Acetylphenyl)-N-(ethylsulfonyl)ethanesulfonamide (8b). It
17.6 Hz, 1H, upfield H of CH
2
2
), 4.12
was obtained from the reaction of 7 and 2b as colorless microcrystals
(d, J = 17.6 Hz, 1H, downfield H of CH
2
◦
from benzene – pet. ether (60–80 C) mixture as 1:3 v/v with mp
1
= 7.7 Hz, 1H, arom. H), 6.88 (t, J = 7.5 Hz, 1H, arom. H), 7.18 (t, J = 7.7
Hz, 1H, arom. H), 7.31 (d, J = 7.3 Hz, 1H, arom. H), 7.63 (d, J = 8.5 Hz,
◦
ꢀ 1
1
18–120 C and yield 88% (1.40 g). IR:
ν
max/cm 1682, 1597, 1501. H
1
3
NMR (DMSO‑d
H, H
6
) δ (ppm): 1.36 (t, J = 7.4 Hz, 6H, 2 H
3
CH
2
CS), 2.63 (s,
2H, arom. H), 8.00 (d, J = 8.4 Hz, 2H, arom. H), 10.30 (s, 1H, NH).
C
3
3
CCO), 3.70 (q, J = 7.3 Hz, 4H, 2 SCH
2
), 7.66 (d, J = 8.3 Hz, 2H,
NMR (DMSO‑d
6
3 2 2
) δ (ppm): 7.6 (CH ), 45.8 (CH CO), 49.8 (SCH ), 72.9
1
3
arom. H), 8.05 (d, J = 8.3 Hz, 2H, arom. H). C NMR (DMSO‑d
6
) δ
), 129.2, 131.8, 137.7
(319.39): C, 45.13;
(indolyl C-3), 109.3, 121.1, 123.6, 128.9, 131.5, 131.7, 137.0, 137.7,
142.8 (arom. C), 178.1 [indolyl CO (C-2)], 195.8 (ketonic CO). Anal.
(
ppm): 7.7 (H
3
CH
2
CS), 26.9 (H
3
CCO), 49.9 (SCH
17NO
2
(
arom. C), 197.3 (CO). Anal. Calcd. for C12
H
5
S
2
Calcd. for C20
22 2 7 2
H N O S (466.52): C, 51.49; H, 4.75; N, 6.00. Found: C,
H, 5.37; N, 4.39. Found: C, 45.07; H, 5.40; N, 4.29.
51.60; H, 4.82; N, 6.05.
1
3

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
4
.1.5.4. N-{4-[2-(5-Chloro-3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-
4.1.6. Acidic dehydration of 9 (general procedure)
N-(ethylsulfonyl)ethanesulfonamide (9d). It was obtained from the reac-
Hydrochloric acid (25 ml, 25%) was added dropwise (10 min.) to a
tion of 8b and 4b as colorless solid, reaction time 72 h, with mp
magnetically stirred solution of 9 (5 mmol) in absolute ethanol (12.5 ml)
91–193 ◦C and yield 66% (1.66 g). IR:
ν
max/cm 3252, 1695, 1682,
ꢀ 1
at room temperature (20–25 C) for the appropriate time. The separated
solid was collected, washed with water and crystallized from a suitable
◦
1
1
3
1
1
620, 1601. H NMR (DMSO‑d
6
) δ (ppm): 1.34 (t, J = 7.3 Hz, 6H, 2 CH
+ upfield H of CH CO), 4.20 (d, J = 18.0 Hz,
CO), 6.27 (s, 1H, OH), 6.85 (d, J = 8.2 Hz, 1H,
3
),
.66–3.71 (m, 5H, 2 SCH
H, downfield H of CH
2
2
solvent affording the corresponding 10.
2
arom. H), 7.24 (dd, J = 1.6, 8.2 Hz, 1H, arom. H), 7.42 (d, J = 1.1 Hz,
H, arom. H), 7.64 (d, J = 8.3 Hz, 2H, arom. H), 8.00 (d, J = 8.3 Hz, 2H,
4.1.6.1. (E)-N-(Methylsulfonyl)-N-{4-[2-(2-oxoindolin-3-ylidene)acetyl]
phenyl}methanesulfonamide (10a). It was obtained from acidic dehy-
dration of 9a for 72 h as red microcrystals from methanol with mp
1
1
3
arom. H), 10.45 (s, 1H, NH). C NMR (DMSO‑d
6
) δ (ppm): 7.7 (CH
), 73.0 (indolyl C-3), 110.8, 124.0, 125.2,
28.7, 129.0, 131.8, 133.8, 136.8, 138.0, 141.9 (arom. C), 178.0
21ClN
500.97): C, 47.95; H, 4.23; N, 5.59. Found: C, 48.13; H, 4.36; N, 5.78.
3
),
◦
ꢀ 1
4
1
5.8 (CH
2
CO), 49.9 (SCH
2
239–241 C and yield 66% (1.39 g). IR: νmax/cm 3194, 1717, 1663,
1
1505. H NMR (DMSO‑d ) δ (ppm): 3.61 (s, 6H, 2 SCH ), 6.91 (d, J = 7.8
6
3
[
indolyl CO (C-2)], 196.0 (ketonic CO). Anal. Calcd. for C20
H
2
O
7
S
2
Hz, 1H, arom. H), 6.98 (t, J = 7.7 Hz, 1H, arom. H), 7.37 (t, J = 7.7 Hz,
1H, arom. H), 7.75 (s, 1H, olefinic CH), 7.79 (d, J = 8.5 Hz, 2H, arom.
H), 8.11 (d, J = 7.7 Hz, 1H, arom. H), 8.18 (d, J = 8.5 Hz, 2H, arom. H),
(
4
.1.5.5. N-{4-[2-(3-Hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-N-(pro-
10.83 (s, 1H, NH). 13C NMR (DMSO‑d
) δ (ppm): 43.1 (SCH ), 110.3,
6 3
pylsulfonyl)propane-1-sulfonamide (9e). It was obtained from the reac-
119.8, 121.7, 125.3, 126.8, 129.6, 131.6, 133.1, 137.0, 138.16, 138.23,
tion of 8c and 4a as colorless solid, reaction time 48 h, with mp
145.1 (arom. C + olefinic C), 168.1 [indolyl CO (C-2)], 190.4 (ketonic
91–193 ◦C and yield 39% (0.96 g). IR:
ν
max/cm 3422, 3256, 1740,
ꢀ 1
1
1
2
1
1
16 2 6 2
CO). Anal. Calcd. for C18H N O S (420.45): C, 51.42; H, 3.84; N, 6.66.
1
678, 1624, 1601. H NMR (DMSO‑d
6
) δ (ppm): 1.00 (t, J = 7.4 Hz, 6H,
CH
), 3.61 (d, J = 17.9 Hz,
CO), 3.65 (t, J = 7.6 Hz, 4H, 2 SCH ), 4.10 (d, J =
7.7 Hz, 1H, downfield H of CH
CO), 6.09 (s, 1H, OH), 6.82 (d, J = 7.7
Found: C, 51.31; H, 3.71; N, 6.56.
CH
3
), 1.80 (sextet, J = 7.4 Hz, 4H, 2 SCH
2
2
H upfield H of CH
2
2
4.1.6.2. (E)-N-(Ethylsulfonyl)-N-{4-[2-(2-oxoindolin-3-ylidene)acetyl]
phenyl}ethanesulfonamide (10b). It was obtained from acidic dehydra-
tion of 9c for 72 h as red microcrystals from methanol with mp
220–222 ◦C and yield 70% (1.56 g). IR: νmax/cm 3395, 3159, 1717,
2
Hz, 1H, arom. H), 6.86 (t, J = 7.5 Hz, 1H, arom. H), 7.17 (t, J = 7.6 Hz,
H, arom. H), 7.29 (d, J = 7.2 Hz, 1H, arom. H), 7.61 (d, J = 8.4 Hz, 2H,
ꢀ 1
1
1
3
1
arom. H), 7.98 (d, J = 8.4 Hz, 2H, arom. H), 10.28 (s, 1H, NH). C NMR
1663, 1605. H NMR (DMSO‑d ) δ (ppm): 1.36 (t, J = 7.4 Hz, 6H, 2 CH ),
6
3
(
DMSO‑d
SCH ), 72.9 (indolyl C-3), 109.3, 121.0, 123.6, 128.9, 131.5, 131.7,
37.0, 137.7, 142.8 (arom. C), 178.1 [indolyl CO (C-2)], 195.8 (ketonic
CO). Anal. Calcd. for C22 (494.58): C, 53.43; H, 5.30; N, 5.66.
Found: C, 53.24; H, 5.41; N, 5.72.
6
) δ (ppm): 12.4 (CH
3
), 16.5 (SCH
2
CH
2
), 45.8 (CH
2
CO), 56.6
3.71 (q, J = 7.4 Hz, 4H, 2 SCH ), 6.90 (d, J = 7.8 Hz, 1H, arom. H), 6.98
2
(
2
(t, J = 7.6 Hz, 1H, arom. H), 7.37 (t, J = 7.7 Hz, 1H, arom. H), 7.73 (d, J
1
= 7.8 Hz, 2H, arom. H), 7.74 (s, 1H, olefinic CH), 8.10 (d, J = 7.7 Hz, 1H,
1
3
H
26
N
2
O
S
7 2
arom. H), 8.17 (d, J = 8.5 Hz, 2H, arom. H), 10.83 (s, 1H, NH). C NMR
(DMSO‑d ) δ (ppm): 7.6 (CH ), 49.9 (SCH ), 110.3, 119.8, 121.7, 125.3,
6
3
2
1
26.8, 129.5, 132.1, 133.2, 136.9, 138.1, 145.1 (arom. C + olefinic C),
168.1 [indolyl CO (C-2)], 190.3 (ketonic CO). Anal. Calcd. for
20 20 2 6 2
C H N O S (448.51): C, 53.56; H, 4.49; N, 6.25. Found: C, 53.42; H,
4
.1.5.6. N-{4-[2-(5-Chloro-3-hydroxy-2-oxoindolin-3-yl)acetyl]phenyl}-
N-(propylsulfonyl)propane-1-sulfonamide (9f). It was obtained from the
reaction of 8c and 4b as colorless solid, reaction time 72 h, with mp
4.42; N, 6.11.
79–181 ◦C and yield 46% (1.21 g). IR:
ν
max/cm 3356, 3256, 1721,
ꢀ 1
1
1
2
2
1
682, 1620, 1601. H NMR (DMSO‑d
6
) δ (ppm): 1.02 (t, J = 7.4 Hz, 6H,
CH
), 3.67 (t, J = 7.7 Hz, 4H,
), 3.71 (d, J = 18.9 Hz, 1H upfield H of CH CO), 4.22 (d, J = 18.0
CO), 6.28 (s, 1H, OH), 6.87 (d, J = 8.3 Hz,
H, arom. H), 7.25 (dd, J = 1.9, 8.3 Hz, 1H, arom. H), 7.43 (br s, 1H,
arom. H), 7.65 (d, J = 8.4 Hz, 2H, arom. H), 8.01 (d, J = 8.4 Hz, 2H,
arom. H), 10.46 (s, 1H, NH). 13C NMR (DMSO‑d
) δ (ppm): 13.0 (CH ),
), 73.5 (indolyl C-3), 111.3,
24.5, 125.7, 128.8, 129.2, 129.5, 132.3, 134.3, 137.3, 138.4, 142.4
4.1.6.3. (E)-N-{4-[2-(5-Chloro-2-oxoindolin-3-ylidene)acetyl]phenyl}-N-
(ethylsulfonyl)ethanesulfonamide (10c). It was obtained from acidic
dehydration of 9d for 72 h as red microcrystals from methanol with mp
CH
3
), 1.83 (sextet, J = 7.4 Hz, 4H, 2 SCH
2
2
SCH
2
2
◦
ꢀ 1
Hz, 1H, downfield H of CH
2
222–224 C and yield 77% (1.85 g). IR: νmax/cm 3171, 1717, 1663,
1
1
1601. H NMR (DMSO‑d ) δ (ppm): 1.37 (t, J = 7.3 Hz, 6H, 2 CH ), 3.72
6
3
(q, J = 7.2 Hz, 4H, 2 SCH ), 6.89 (d, J = 8.3 Hz, 1H, arom. H), 7.40 (dd,
2
6
3
J = 1.6, 8.3 Hz, 1H, arom. H), 7.74 (d, J = 8.3 Hz, 2H, arom. H), 7.80 (s,
1
1
7.1 (SCH
2
CH
2
), 46.3 (CH
2
CO), 57.2 (SCH
2
1H, olefinic CH), 8.18 (d, J = 8.6 Hz, 2H, arom. H), 8.19 (d, J = 2.0 Hz,
1H, arom. H), 10.95 (s, 1H, NH). 13C NMR (DMSO‑d ) δ (ppm): 7.6
6
(
arom. C), 178.4 [indolyl CO (C-2)], 196.4 (ketonic CO). Anal. Calcd. for
25ClN (529.02): C, 49.95; H, 4.76; N, 5.30. Found: C, 50.08;
H, 4.92; N, 5.39.
(CH ), 49.9 (SCH ), 111.8, 121.3, 125.6, 126.3, 126.5, 129.6, 132.1,
3
2
C
22
H
2
O
7
S
2
132.6, 136.4, 138.1, 138.2, 144.0 (arom. C + olefinic C), 167.8 [indolyl
CO (C-2)], 189.9 (ketonic CO). Anal. Calcd. for C20 ClN O S
H
19
2 6 2
(
482.95): C, 49.74; H, 3.97; N, 5.80. Found: C, 49.55; H, 3.86; N, 5.73.
4
.1.5.7. N-{4-[2-(3-Hydroxy-5-methoxy-2-oxoindolin-3-yl)acetyl]
phenyl}-N-(propylsulfonyl)propane-1-sulfonamide (9 g). It was obtained
from the reaction of 8c and 4c as colorless solid, reaction time 72 h, with
4.1.7. Reaction of 4a-e with 11a,b (general procedure)
A mixture of equimolar amounts of the appropriate isatin 4a-e (5
mmol) and the corresponding 2-acetylbenzimidazole 11a,b [95,96] in
ethanol absolute (15 ml) containing quantitative amount of diethyl-
◦
ꢀ 1
mp 161–163 C and yield 44% (1.14 g). IR:
ν
max/cm 3348, 1717,
1
1
686, 1605. H NMR (DMSO‑d
6
) δ (ppm): 1.02 (t, J = 7.4 Hz, 6H, 2 CH
CH
), 3.60–3.68 (m, 8H, 2 SCH
CO), 4.12 (d, J = 17.6 Hz, 1H, downfield H of
CO), 6.12 (s, 1H, OH), 6.75 (br s, 2H, arom. H), 7.00 (br s, 1H, arom.
H), 7.64 (d, J = 8.3 Hz, 2H, arom. H), 8.00 (d, J = 8.3 Hz, 2H, arom. H),
3
),
◦
1
.82 (sextet, J = 7.3 Hz, 4H, 2 SCH
+ upfield H of CH
2
2
2
+
amine was stirred at room temperature (20–25 C) for 3 h. The reaction
OCH
CH
3
2
mixture was stored at room temperature overnight, the separated solid
12a–h was collected washed with benzene (10 ml) and used in the next
step without any more purification.
2
1
3
1
0.13 (s, 1H, NH). C NMR (DMSO‑d
SCH CH ), 45.8 (CH CO), 55.3 (OCH ), 56.6 (SCH
), 109.6, 110.9, 113.3, 128.9, 131.7, 132.8, 136.0, 137.0, 137.7, 154.6
6
) δ (ppm): 12.4 (CH
3
), 16.5
(
2
2
2
3
2
), 73.4 (indolyl C-
4.1.7.1. 3-Hydroxy-3-[2-(1-methyl-1H-benzo[d]imidazol-2-yl)-2-
3
oxoethyl]indolin-2-one (12a). It was obtained from the reaction of 4a
◦
(
arom. C), 178.1 [indolyl CO (C-2)], 195.8 (ketonic CO). Anal. Calcd. for
(524.60): C, 52.66; H, 5.38; N, 5.34. Found: C, 52.82; H,
and 11a as colorless solid with mp 139–141 C and yield 84% (1.35 g).
ꢀ
1
1
C
23
H
28
2
N O
8
S
2
IR:
ν
max
/cm 3568, 3302, 3213, 1709, 1690, 1678, 1628, 1612. H
5
.46; N, 5.51.
NMR (DMSO‑d ) δ (ppm): 3.73 (d, J = 17.1 Hz, 1H upfield H of CH CO),
6
2
3
.84 (s, 3H, NCH
3
), 4.36 (d, J = 17.1 Hz, 1H, downfield H of CH
2
CO),
1
4

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
6
1
.29 (s, 1H, OH), 6.85 (t, J = 7.8 Hz, 2H, arom. H), 7.17 (t, J = 7.5 Hz,
H, arom. H), 7.30 (d, J = 7.2 Hz, 1H, arom. H), 7.34 (t, J = 7.6 Hz, 1H,
(d, J = 8.0 Hz, 1H, arom. H), 7.84 (d, J = 8.0 Hz, 1H, arom. H), 10.17 (s,
1H, NH). 13C NMR (DMSO‑d
6
3 2
) δ (ppm): 31.9 (NCH ), 46.8 (CH CO),
arom. H), 7.41 (t, J = 7.6 Hz, 1H, arom. H), 7.61 (d, J = 8.1 Hz, 1H,
55.3 (OCH
123.6, 125.7, 132.4, 135.8, 136.7, 140.8, 145.7, 154.6 (arom. C), 178.0
[indolyl CO (C-2)], 191.3 (ketonic CO). Anal. Calcd. for C19
3
), 73.6 (indolyl C-3) 109.9, 111.0, 111.5, 113.7, 121.2,
1
3
arom. H), 7.83 (d, J = 8.1 Hz, 1H, arom. H), 10.36 (s, 1H, NH). C NMR
DMSO‑d ) δ (ppm): 31.9 (NCH ), 46.8 (CH CO), 73.2 (indolyl C-3)
09.6, 111.6, 121.2, 121.4, 123.6, 123.9, 125.8, 129.2, 131.4, 136.7,
40.8, 142.7, 145.6 (arom. C), 178.1 [indolyl CO (C-2)], 191.3 (ketonic
(321.34): C, 67.28; H, 4.71; N, 13.08.
Found: C, 67.18; H, 4.57; N, 12.92.
(
6
3
2
17 3 4
H N O
1
1
(351.36): C, 64.95; H, 4.88; N, 11.96. Found: C, 65.13; H, 5.01; N, 12.07.
CO). Anal. Calcd. for C18
H
15
3
N O
3
4.1.7.6. 3-[2-(1-Ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoethyl]-3-hydroxy-
5-methoxyindolin-2-one (12f). It was obtained from the reaction of 4c
◦
and 11b as colorless solid with mp 179–181 C and yield 89% (1.62 g).
4
.1.7.2. 3-[2-(1-Ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoethyl]-3-hydrox-
IR:
ν
max/cm 3422, 3167, 1709, 1682, 1639. 1H NMR (DMSO‑d
ꢀ
1
6
) δ
), 3.67 (d, J =
CO), 4.33–4.42 (m, 3H, NCH CH
2
CO), 6.29 (s, 1H, OH), 6.72 (s, 2H, arom. H), 6.91 (s,
yindolin-2-one (12b). It was obtained from the reaction of 4a and 11b as
(ppm): 1.11 (t, J = 6.3 Hz, 3H, CH
16.3 Hz, 1H upfield H of CH
downfield H of CH
3 3
), 3.54 (s, 3H, OCH
◦
colorless solid with mp 134–136 C and yield 74% (1.24 g). IR:
ν
max
/
2
2
3
+
ꢀ
1
1
cm 3595, 3306, 3213, 1710, 1690, 1686, 1624. H NMR (DMSO‑d
ppm): 1.09 (t, J = 6.6 Hz, 3H, CH
of CH CO), 4.38 (br d, 3H, NCH CH
H, OH), 6.82–6.83 (m, 2H, arom. H), 7.15 (t, J = 7.5 Hz, 1H, arom. H),
.27 (d, J = 7.0 Hz, 1H, arom. H), 7.35 (t, J = 7.3 Hz, 1H, arom. H), 7.43
6
) δ
(
3
), 3.69 (d, J = 16.6 Hz, 1H upfield H
1H, arom. H), 7.36 (t, J = 7.2 Hz, 1H, arom. H), 7.43 (t, J = 7.2 Hz, 1H,
arom. H), 7.67 (d, J = 8.0 Hz, 1H, arom. H), 7.86 (d, J = 8.0 Hz, 1H,
2
2
3
+ downfield H of CH CO), 6.29 (s,
2
1
7
arom. H), 10.17 (s, 1H, NH). 13C NMR (DMSO‑d
6
) δ (ppm): 15.1 (CH
3
),
39.7 (NCH CH ), 46.7 (CH CO), 55.3 (OCH ), 73.8 (indolyl C-3) 109.9,
2 3 2 3
(
t, J = 7.3 Hz, 1H, arom. H), 7.66 (d, J = 8.2 Hz, 1H, arom. H), 7.85 (d, J
8.1 Hz, 1H, arom. H), 10.35 (s, 1H, NH). 13C NMR (DMSO‑d
) δ (ppm):
5.2 (CH ), 39.8 (NCH CH ), 46.7 (CH CO), 73.3 (indolyl C-3) 109.6,
111.0, 111.5, 113.9, 121.3, 123.6, 125.8, 132.3, 135.7, 141.0, 145.2,
=
6
154.6 (arom. C), 177.9 [indolyl CO (C-2)], 191.2 (ketonic CO). Anal.
1
1
1
3
2
3
2
19 3 4
Calcd. for C20H N O (365.39): C, 65.74; H, 5.24; N, 11.50. Found: C,
11.5, 121.3, 121.4, 123.7, 123.9, 125.9, 129.2, 131.2, 135.8, 141.0,
65.81; H, 5.33; N, 11.68.
42.6, 145.1 (arom. C), 178.1 [indolyl CO (C-2)], 191.3 (ketonic CO).
Anal. Calcd. for C19
H
17
N
3
O
3
(335.36): C, 68.05; H, 5.11; N, 12.53.
4.1.7.7. 3-Hydroxy-3-[2-(1-methyl-1H-benzo[d]imidazol-2-yl)-2-
oxoethyl]-1-(piperidin-1-ylmethyl)indolin-2-one (12 g). It was obtained
from the reaction of 4d [97] and 11a as colorless solid with mp
Found: C, 68.21; H, 5.02; N, 12.67.
◦
ꢀ 1
4
2
.1.7.3. 5-Chloro-3-hydroxy-3-[2-(1-methyl-1H-benzo[d]imidazol-2-yl)-
147–149 C and yield 75% (1.57 g). IR:
ν
max/cm 3321, 1701, 1686,
C-4),
C-2/
CO), 3.84 (s, 3H, NCH ),
CO), 6.37 (s, 1H, OH),
1
-oxoethyl]indolin-2-one (12c). It was obtained from the reaction of 4b
1616. H NMR (DMSO‑d
6
) δ (ppm): 1.36 (br s, 2H, piperidinyl H
C-3/5), 2.57 (br d, 4H, piperidinyl H
6), 3.79 (d, J = 17.1 Hz, 1H upfield H of CH
4.37–4.40 (m, 3H, NCH
2
◦
and 11a as colorless solid with mp 186–188 C and yield 71% (1.26 g).
1.47 (br s, 4H, piperidinyl H
2
2
ꢀ 1
1
IR:
δ (ppm): 3.82 (d, J = 17.7 Hz, 1H upfield H of CH
NCH
), 4.36 (d, J = 17.6 Hz, 1H, downfield H of CH
OH), 6.85 (d, J = 8.2 Hz, 1H, arom. H), 7.23 (d, J = 8.1 Hz, 1H, arom. H),
.35 (t, J = 7.4 Hz, 1H, arom. H), 7.40–7.44 (m, 2H, arom. H), 7.64 (d, J
8.1 Hz, 1H, arom. H), 7.84 (d, J = 8.1 Hz, 1H, arom. H), 10.50 (s, 1H,
ν
max/cm 3348, 3298, 1717, 1686, 1670, 1624. H NMR (DMSO‑d
CO), 3.88 (s, 3H,
CO), 6.39 (s, 1H,
6
)
2
3
2
2
N + downfield H of CH
2
3
2
6.92 (t, J = 6.9 Hz, 1H, arom. H), 7.11 (d, J = 7.4 Hz, 1H, arom. H), 7.24
(t, J = 7.3 Hz, 1H, arom. H), 7.35 (br s, 2H, arom. H), 7.42 (t, J = 7.3 Hz,
1H, arom. H), 7.62 (d, J = 7.9 Hz, 1H, arom. H), 7.83 (d, J = 7.8 Hz, 1H,
7
=
arom. H). 13C NMR (DMSO‑d
) δ (ppm): 23.8 (piperidinyl C-4), 25.4
6
1
3
NH). C NMR (DMSO‑d
6
) δ (ppm): 32.0 (NCH
3
), 46.7 (CH
2
CO), 73.1
(piperidinyl C-3/5), 31.8 (NCH
6), 62.1 (NCH N), 72.9 (indolyl C-3), 109.9, 111.5, 121.2, 121.9, 123.4,
123.5, 125.7, 129.1, 130.4, 136.7, 140.8, 144.2, 145.5 (arom. C), 177.4
[indolyl CO (C-2)], 191.1 (ketonic CO). Anal. Calcd. for C24
3 2
), 47.0 (CH CO), 51.3 (piperidinyl C-2/
(
indolyl C-3) 111.0, 111.6, 121.2, 123.6, 124.3, 125.4, 125.8, 128.9,
2
1
1
33.5, 136.7, 140.8, 141.6, 145.4 (arom. C), 177.8 [indolyl CO (C-2)],
91.3 (ketonic CO). Anal. Calcd. for C18 14ClN (355.78): C, 60.77;
H
3
O
3
26 4 3
H N O
H, 3.97; N, 11.81. Found: C, 61.06; H, 4.09; N, 11.99.
(418.50): C, 68.88; H, 6.26; N, 13.39. Found: C, 69.01; H, 6.10; N, 13.58.
4
.1.7.4. 5-Chloro-3-[2-(1-ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoethyl]-3-
4.1.7.8. 3-Hydroxy-3-[2-(1-methyl-1H-benzo[d]imidazol-2-yl)-2-
hydroxyindolin-2-one (12d). It was obtained from the reaction of 4b and
oxoethyl]-1-(morpholinomethyl)indolin-2-one (12 h). It was obtained
◦
1
1b as colorless solid with mp 169–171 C and yield 75% (1.38 g). IR:
from the reaction of 4e [97] and 11a as pale yellow solid with mp
ꢀ
1
1
168–170 ◦C and yield 77% (1.61 g). IR:
ꢀ 1
ν
max/cm 3464, 3256, 1740, 1701, 1686, 1620. H NMR (DMSO‑d
6
) δ
), 3.80 (d, J = 17.2 Hz, 1H upfield H
CH CO), 6.41
+ downfield H of CH
ν
max/cm 3283, 1717, 1686,
(
ppm): 1.13 (t, J = 6.5 Hz, 3H, CH
3
1612. 1H NMR (DMSO‑d
NCH ), 3.57 (br s, 4H, morpholinyl 2 OCH
upfield H of CH CO), 3.83 (s, 3H, NCH
), 4.38–4.44 (m, 3H, NCH
downfield H of CH
6
) δ (ppm): 2.61 (br d, 4H, morpholinyl 2
), 3.81 (d, J = 16.3 Hz, 1H
N +
of CH
2
CO), 4.35–4.41 (m, 3H, NCH
2
3
2
2
2
(
s, 1H, OH), 6.84 (d, J = 8.1 Hz, 1H, arom. H), 7.22 (d, J = 8.2 Hz, 1H,
2
3
2
arom. H), 7.34–7.38 (m, 2H, arom. H), 7.43 (t, J = 7.3 Hz, 1H, arom. H),
2
CO), 6.40 (s, 1H, OH), 6.95 (t, J = 6.8 Hz, 1H, arom.
7
.67 (d, J = 8.1 Hz, 1H, arom. H), 7.86 (d, J = 8.1 Hz, 1H, arom. H),
0.50 (s, 1H, NH). 13C NMR (DMSO‑d
) δ (ppm): 15.2 (CH ), 39.8
CH ), 46.7 (CH CO), 73.3 (indolyl C-3) 111.0, 111.5, 121.4,
23.7, 124.3, 125.4, 125.9, 128.9, 133.4, 135.7, 141.0, 141.6, 144.9
H), 7.14 (d, J = 7.5 Hz, 1H, arom. H), 7.26 (t, J = 6.7 Hz, 1H, arom. H),
7.36 (br s, 2H, arom. H), 7.42 (t, J = 7.1 Hz, 1H, arom. H), 7.62 (d, J =
1
6
3
1
3
(
NCH
2
3
2
8.0 Hz, 1H, arom. H), 7.84 (d, J = 7.9 Hz, 1H, arom. H). C NMR
1
(DMSO‑d
6
3
) δ (ppm): 31.8 (NCH ), 46.9 (CH
2
CO), 50.6 (morpholinyl
), 72.9 (indolyl C-3)
(
arom. C), 177.8 [indolyl CO (C-2)], 191.2 (ketonic CO). Anal. Calcd. for
16ClN (369.81): C, 61.71; H, 4.36; N, 11.36. Found: C, 61.85; H,
.42; N, 11.45.
NCH ), 61.4 (NCH
2
2
N), 66.1 (morpholinyl OCH
2
C
19
H
3
O
3
109.8, 111.5, 121.2, 122.1, 123.4, 123.6, 125.7, 129.1, 130.4, 136.7,
4
140.8, 143.9, 145.5 (arom. C), 177.4 [indolyl CO (C-2)], 191.2 (ketonic
CO). Anal. Calcd. for C23
24 4 4
H N O (420.47): C, 65.70; H, 5.75; N, 13.33.
4
.1.7.5. 3-Hydroxy-5-methoxy-3-[2-(1-methyl-1H-benzo[d]imidazol-2-
Found: C, 65.51; H, 5.81; N, 13.47.
yl)-2-oxoethyl]indolin-2-one (12e). It was obtained from the reaction of
◦
4
c and 11a as colorless solid with mp 174–176 C and yield 78% (1.37
4.1.8. Acidic dehydration of 12a-h (general procedure)
ꢀ
1
1
g). IR:
ν
max/cm 3186, 1724, 1686, 1655, 1612. H NMR (DMSO‑d
), 3.71 (d, J = 16.9 Hz, 1H upfield H of
), 4.33 (d, J = 16.9 Hz, 1H, downfield H of
CO), 6.27 (s, 1H, OH), 6.73 (s, 2H, arom. H), 6.94 (s, 1H, arom. H),
6
) δ
Hydrochloric acid (25 ml, 25%) was added dropwise (10 min.) to a
magnetically stirred solution of 12a-h (5 mmol) in absolute ethanol
(12.5 ml) at room temperature (20–25 ◦C). The reaction mixture was
kept stirring under the same conditions for 4 h and stored overnight at
room temperature. The separated solid was collected, washed with
(
ppm): 3.57 (s, 3H, OCH
3
CH
CH
CO), 3.86 (s, 3H, NCH
2 3
2
7
.35 (t, J = 7.0 Hz, 1H, arom. H), 7.43 (t, J = 7.2 Hz, 1H, arom. H), 7.63
1
5

A.S. Girgis et al.
Bioorganic Chemistry 114 (2021) 105131
water and crystallized from a suitable solvent affording the corre-
116.7, 126.8, 130.3, 131.2, 131.4, 131.7, 132.2, 132.4, 135.8, 136.3,
sponding 13a-f.
138.9, 145.0, 145.2 (arom. C + olefinic C), 166.3 [indolyl CO (C-2)],
1
15 3 3
71.1 (ketonic CO). Anal. Calcd. for C19H N O (333.35): C, 68.46; H,
4
.1.8.1. (E)-3-[2-(1-Methyl-1H-benzo[d]imidazol-2-yl)-2-oxoethylidene]
4.54; N, 12.61. Found: C, 68.61; H, 4.68; N, 12.53.
indolin-2-one (13a). It was obtained from acidic dehydration of 12a, 12
g or 12 h as colorless microcrystals from N,N-dimethylformamide with
4.1.8.6. (E)-3-[2-(1-Ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoethylidene]-5-
methoxyindolin-2-one (13f). It was obtained from acidic dehydration of
12f as pale yellow microcrystals from N,N-dimethylformamide with mp
◦
mp 349–350 C and yield 84, 73, 77% (1.27, 1.10, 1.16 g from reaction
ꢀ 1
of 12a, 12 g and 12 h, respectively). IR: max/cm 3124, 1694, 1585.
ν
1
◦
ꢀ 1
1
H NMR (CF
3
CO
2
D) δ (ppm): 4.26 (s, 3H, NCH
3
), 7.57–7.91 (m, 6H,
317–319 C and yield 95% (1.65 g). IR:
ν
max/cm 3121, 1694, 1620. H
CH ), 3.96 (s,
), 7.61–7.66 (m, 3H, arom. H),
arom. H), 8.21 (d, J = 8.4 Hz, 1H, arom. H), 8.66 (s, 1H, olefinic H), 8.83
NMR (CF
3H, OCH
3
CO
2
D) δ (ppm): 1.63 (t, J = 7.2 Hz, 3H, NCH
2
3
1
3
(
d, J = 8.5 Hz, 1H, arom. H), 11.50 (s, 1H, NH). C NMR (CF
ppm): 35.3 (NCH ), 114.9, 116.8, 125.4, 128.4, 1629.0, 130.4, 131.2,
31.7, 132.4, 135.4, 136.0, 136.5, 141.1, 141.6, 146.0 (arom. C +
olefinic C), 149.8 [indolyl CO (C-2)], 171.6 (ketonic CO). Anal. Calcd.
for C18 (303.32): C, 71.28; H, 4.32; N, 13.85. Found: C, 71.49;
H, 4.46; N, 14.01.
3
CO
2
D) δ
3
), 4.82 (q, J = 7.1 Hz, 2H, NCH
2
(
3
7.75 (t, J = 5.9 Hz, 2H, arom. H), 8.18 (d, J = 9.4 Hz, 1H, arom. H), 8.38
(d, J = 2.4 Hz, 1H, arom. H), 8.77 (s, 1H, olefinic H), 11.50 (s, 1H, NH).
1
1
3
3 2 3 2 3
C NMR (CF CO D) δ (ppm): 15.6 (CH ), 45.1 (NCH ), 57.8 (OCH ),
H
13
N
3
O
2
105.9, 114.8, 116.8, 126.2, 130.3, 130.9, 131.4, 131.7, 132.6, 134.8,
137.4, 137.8, 145.3, 146.3 (arom. C + olefinic C), 165.9 [indolyl CO (C-
2
17 3 3
)], 171.6 (ketonic CO). Anal. Calcd. for C20H N O (347.37): C, 69.15;
4
.1.8.2. (E)-3-[2-(1-Ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoethylidene]
H, 4.93; N, 12.10. Found: C, 68.96; H, 4.75; N, 11.99.
indolin-2-one (13b). It was obtained from acidic dehydration of 12b as
◦
colorless microcrystals from n-butanol with mp 301–303 C and yield
4
4
.2. X-ray studies
max/cm 3129, 1697, 1589. 1H NMR (CF
ꢀ 1
7
5% (1.19 g). IR: CO D) δ
ν
3 2
(
ppm): 1.75 (t, J = 7.2 Hz, 3H, NCH
NCH
), 7.70–7.76 (m, 2H, arom. H), 7.84–7.85 (m, 2H, arom. H), 7.94
t, J = 7.7 Hz, 1H, arom. H), 8.03 (t, J = 7.6 Hz, 1H, arom. H), 8.35 (d, J
8.5 Hz, 1H, arom. H), 8.81 (s, 1H, olefinic H), 8.99 (d, J = 8.7 Hz, 1H,
2
CH
3
), 4.99 (q, J = 7.2 Hz, 2H,
Mentioned in details in the supplementary file.
2
(
.3. Biological studies
=
1
3
arom. H), 11.50 (s, 1H, NH). C NMR (CF
3
CO
), 114.7, 116.6, 124.7, 127.9, 128.4, 130.7, 131.17, 131.22,
32.4, 134.8, 135.0, 135.6, 142.0, 145.9 (arom. C + olefinic C), 150.5
2 3
D) δ (ppm): 15.5 (CH ),
Mentioned in details in the supplementary file.
4
1
5.0 (NCH
2
[
indolyl CO (C-2)], 171.9 (ketonic CO). Anal. Calcd. for C19
H
15
N
3
O
2
4.4. Docking studies
(
317.35): C, 71.91; H, 4.76; N, 13.24. Found: C, 71.79; H, 4.68; N, 13.05.
Mentioned in details in the supplementary file.
4
.1.8.3. (E)-5-Chloro-3-[2-(1-methyl-1H-benzo[d]imidazol-2-yl)-2-oxoe-
thylidene]indolin-2-one (13c). It was obtained from acidic dehydration
of 12c as colorless microcrystals from N,N-dimethylformamide with mp
Declaration of Competing Interest
◦
ꢀ 1
1
3
54–356 C and yield 98% (1.65 g). IR:
ν
max/cm 3117, 1694, 1585. H
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.
NMR (CF
3
CO
2
D) δ (ppm): 4.42 (s, 3H, NCH
3
), 7.63–7.81 (m, 5H, arom.
H), 8.17 (d, J = 9.0 Hz, 1H, arom. H), 8.77 (s, 1H, olefinic H), 8.91 (br s,
H, arom. H), 11.50 (s, 1H, NH). 13C NMR (CF
CO D) δ (ppm): 35.3
NCH ), 114.7, 116.6, 125.8, 127.0, 128.8, 130.8, 131.4, 132.2, 133.7,
36.09, 136.14, 137.6, 142.4, 143.0, 147.1 (arom. C + olefinic C), 149.9
12ClN
337.76): C, 64.01; H, 3.58; N, 12.44. Found: C, 63.85; H, 3.39; N, 12.30.
1
3
2
(
3
Acknowledgments
1
[
indolyl CO (C-2)], 171.8 (ketonic CO). Anal. Calcd. for C18
H
3 2
O
This work was supported financially by National Research Centre,
Egypt, project ID: 12060101.
(
4
.1.8.4. (E)-5-Chloro-3-[2-(1-ethyl-1H-benzo[d]imidazol-2-yl)-2-oxoe-
Appendix A. Supplementary material
thylidene]indolin-2-one (13d). It was obtained from acidic dehydration
of 12d as colorless microcrystals from N,N-dimethylformamide with mp
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.bioorg.2021.105131.
◦
ꢀ 1
1
3
25–327 C and yield 93% (1.63 g). IR:
ν
max/cm 3129, 1694, 1585. H
NMR (CF
3
CO
2
D) δ (ppm): 1.77 (t, J = 7.2 Hz, 3H, NCH
2
CH ), 5.04 (q, J
3
=
7.1 Hz, 2H, NCH
2
), 7.69–7.75 (m, 2H, arom. H), 7.83–7.91 (m, 3H,
References
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3
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