Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and 2-aminoselenophene-3-carbonitrile unit

Article abstract of DOI:10.1007/s00706-020-02573-x

A series of novel coumarins with 2-amino-3-cyanoselenophen-5-yl unit on C-3 have been synthesized. These compounds prepared easily at room temperature, in a short time and in high yield. The importance of biheterocyclic units as dominant structural motif of coumarin derivatives has been well recognized. Anti-cancer activity screening on MCF-7 cell line allowed identification of 2-amino-5-(6-bromo-2-oxo-2H-chromen-3-yl)selenophene-3-carbonitrile with the highest level of cytotoxic activity with mean IC₅₀ and cLogP (partition co-efficient) values 10.84 μM and 3.18, respectively. The most radical scavenging compound was also recognized. Graphic abstract: [Figure not available: see fulltext.].

Full text of DOI:10.1007/s00706-020-02573-x

Monatshefte für Chemie - Chemical Monthly
https://doi.org/10.1007/s00706-020-02573-x
ORIGINAL PAPER
Synthesis and antiproliferative evaluation of novel biheterocycles
based on coumarin and 2‑aminoselenophene‑3‑carbonitrile unit
Mehmet Erşatır1 · Metin Yıldırım2 · Elife Sultan Giray1 · Serap Yalın2
Received: 31 December 2019 / Accepted: 25 February 2020
© Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract
A series of novel coumarins with 2-amino-3-cyanoselenophen-5-yl unit on C-3 have been synthesized. These compounds
prepared easily at room temperature, in a short time and in high yield. The importance of biheterocyclic units as dominant
structural motif of coumarin derivatives has been well recognized. Anti-cancer activity screening on MCF-7 cell line allowed
identifcation of 2-amino-5-(6-bromo-2-oxo-2H-chromen-3-yl)selenophene-3-carbonitrile with the highest level of cytotoxic
activity with mean IC50 and cLogP (partition co-efcient) values 10.84 µM and 3.18, respectively. The most radical scaveng-
ing compound was also recognized.
Graphic abstract
Keywords Coumarin · Selenophene · Antitumor agents · Heterocycles · Antioxidant activity
Introduction
75 will sufer from cancer [2]. For treatment of cancer dis-
eases many eforts have been carried out and although very
important progress has been made some of cancer patients
do not respond to therapy or recurrence subsequent initial
response. Nevertheless, chemotherapy is a basic approach
for the treatment of cancer diseases and then new drug
designs and synthesis is still necessary.
Cancer is the second deadliest form of disease worldwide.
About 10 million people died in 2018 due to cancer. Accord-
ing to the World Health Organization (WHO) report cancer
is one of the prominent cause of death in the world and based
on, more than 13 million cancers death will happen in 2030
[1]. It was also estimated that one of fve people before age
Biheterocycles are an important class of organic deriva-
tives due to their widespread application in organic synthe-
sis, advanced materials, and pharmaceuticals [3, 4]. Both
natural and synthetic biheterocyclic compounds play vital
role in drug development. The most efcient approaches
are chemical modifcation of biologically active naturally
found molecules. Coumarins (1,2-benzopyrones) are natu-
rally found molecules and widely distributed in plants. Now-
adays, to discover and expand the chemical properties of
coumarins, many synthetic procedures are developing. They
exhibit a wide range of biological activities and applications
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s00706-020-02573-x) contains
supplementary material, which is available to authorized users.
* Elife Sultan Giray
esgiray@gmail.com
1
Department of Chemistry, Arts and Science Faculty,
Cukurova University, Adana, Turkey
2
Department of Biochemistry, Faculty of Pharmacy, Mersin
University, Mersin, Turkey
Vol.:(0123456789)
1 3

M. Erşatır et al.
due to the ability to exert noncovalent interactions with
many enzymes and receptors in living organisms. Hence,
application of coumarins as anti-neurodegenerative, anti-
cancer, anticoagulant, anti-infammatory, antioxidant, antivi-
ral, anti-diabetics, antibacterial, human monoamine oxidase
inhibitory, antichloine esterase, and antifungal agents are
widely appeared in the literature [5–9]. Coumarin deriva-
tives are also commercially signifcant groups of organic
fuorescent materials [10–12].
investigated (Fig. 1). This is the frst report of synthesis of
coumarin–2-aminoselenophene-3-carbonitrile derivatives
and substantial antiproliferative potency in breast cancer
MCF-7 cell lines.
Results and discussion
Synthesis of coumarin–2‑aminoselenophene‑
3‑carbonitrile biheterocycles 3a–3h
Selenophene is one of the important heterocyclic com-
pounds and some selenophene compounds have been found
to possess anti-cancer activity [13, 14]. In addition, these
compounds are very useful synthetic intermediates and they
can function as suitable building blocks to synthesize other
biologically active compounds, such as natural products.
The hybrid compound, formed by the coupling of two
diferent efects and the independent compound with a single
covalent bond, has a novel composite structure which has a
greater pharmacological efect than the sum of each compo-
nent with the synergies of these moieties having independ-
ent efects [15]. It is known that coumarin derivatives show
antiproliferative activity in MCF-7 cell line [16]. On the
other hand, organoselenium compounds have attracted much
attention due to antiviral, antimicrobial, antioxidant and
antiproliferative activity [16–18]. Anti-cancer mechanisms
of selenium derivatives have been linked to apoptosis and
estrogen receptor (ER) stress signal mediators. Selenophenes
are also potential esterogen receptor agonists which increase
binding afnity to estrogen receptors. A number of 2,5-sub-
stituted selenophene compounds displayed enhanced agonist
potency and antiproliferative activity [13].
In this study, new biheterocyclic coumarin derivatives with
modifed 2-aminoselenophene-3-carbonitrile were designed
and synthesized. Scheme 1 shows the synthetic routes of
eight novel coumarin and 2-aminoselenophene-3-carboni-
trile based biheterocyclic compounds.
These new biheterocyclic coumarin derivatives were pre-
pared in three steps. At frst step, 3-acetylcoumarin deriva-
tives 1a–1h were prepared, later condensation reaction of
1a–1h with malononitrile in the presence of diethylamine
gave key intermediates arylidene malononitriles 2a–2h, in
the last stage reaction of arylidene malononitriles 2a–2h
with selenium gave new biheterocyclic compounds 3a–3h.
To prepare these novel biheteroacyclic compounds, Gewald
method was modifed. Starting compounds 3-acetylcou-
marin derivatives 1a–1h were easily obtained with excel-
lent yields (80–99%) by reacting commercially available
corresponding salisylaldehyde and ethyl acetoacetate in
the presence of catalytic amount of diethylamine at room
temperature. Following the optimized procedure, the key
synthetic precursors, 2-[1-(2-oxo-2H-chromen-3-yl)ethyl-
idene]malononitriles 2a–2h were synthesized according to
Knoevenagel reaction. The reaction of compounds 1a–1h
and malononitrile with catalytic amount of diethylamine was
completed easily with good to excellent yield at room tem-
perature (69–98%). Compounds 2a–2h were further applied
with Se in ethanol and catalyzed with diethylamine. Reac-
tions were performed at room temperature and completed
in 3–7 h with moderate yields (50–81%, Table 1). All new
Therefore, the new hybrid compounds that will be
formed by combining coumarin and selenophene com-
pounds are expected to exhibit greater biological activity.
Coumarin–selenophene hybrid compounds are rare in the
literature. The compounds obtained in a limited number of
studies showed signifcant biological activity and these stud-
ies will lead to further studies. Arsenyan et al. In 2019 [19],
they synthesized selenopheno[2,3-f]coumarin compounds.
These new compounds synthesized showed antimetastatic
activity against melanoma and breast cancer. In another
study conducted in 2015 [20], selenopheno[2,3-c]coumarin
compounds were synthesized. The cytotoxic activity of
these compounds was investigated in angiogenesis inhibi-
tory activity and antioxidant efect.
In view of our interest in developing novel coumarin
derivatives, we synthesized new biheterocycles which
include both coumarin and selenophene unit in one frame.
Despite huge synthetic eforts dedicated to the coumarin
scaffold, little work has been devoted to modifying the
lactone function. A series of novel coumarin–2-amin-
oselenophene-3-carbonitrile derivatives were synthe-
sized and biological evaluation of these derivatives were
Fig. 1 2-Aminoselenophene-3-carbonitrile based coumarin deriva-
tives
1 3

Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and…
Scheme 1
Table 1 New coumarin–2-aminoselenophene-3-carbonitrile com-
Table 2 Malononitrile compounds synthesized in diethylamine cata-
pounds synthesized in diethylamine catalyst
lyst
Entry Compound
R
H
Time/h Yield/% M.p./°C
1
2a
2
93
163–165
Entry
Compound
R
Time/h
Yield/%
M.p./°C
(57 [25]) (163 [25])
2
3
2b
2c
7-OCH3
6-Br
3
1
78
170–172
202–204 [25]
1
2
3
4
5
6
7
8
3a
3b
3c
3d
3e
3f
H
5
5
5
5
6
3
5
7
50
68
81
72
51
59
55
50
244–246
187–189
212–214
>250
129–131
225–227
>250
98
7-OCH3
6-Br
7-OH
6-NO2
6,8-Br2
6-Cl
(60 [25])
4
5
6
7
8
2d
2e
2f
2g
2h
7-OH
6-NO2
6,8-Br2
6-Cl
2.5
4.5
3
2
4
80
69
72
79
89
238–240
139–141
198–200
185–187
164–166
3g
3h
7-NEt2
7-NEt2
148–150
(88 [26]) (166–168 [26])
decreasing the molar ratio of 1a–1c to 0.5 was not success-
ful, giving the corresponding coumarin–selenophenes in
46, 56, and 33%, respectively (Table 3, entries 4, 8, and
12).
compounds were individually characterized and their iden-
1
tity confrmed by H NMR and 13C NMR. Among these
compounds, 2-[1-(2-oxo-2H-chromen-3-yl)ethylidene]malo-
nonitrile (2a), 2-[1-(6-bromo-2-oxo-2H-chromen-3-yl)ethyl-
idene]malononitrile (2c), and 2-[1-[7-(N,N-diethylamino)-
2-oxo-2H-chromen-3-yl]ethylidene]malononitrile (2h)
were reported in the literature. However, the yield of these
compounds is higher with our method (Table 2). Novel
coumarin–selenophene-based biheteroacyclic derivatives
namely, 2-amino-5-(2-oxo-2H-chromen-3-yl)selenophene-
3-carbonitriles 3a–3h, for the frst time, were synthesized
in this study.
During the optimization studies, synthesis of main pre-
cursors 2a–2c and target molecules 3a–3c was tested with
diferent bases diethylamine, morpholine, and saturated
NaHCO3. The results are summarized in Table 4.
It is obviously seen that reactions with diethylamine
were completed rapidly and with better results than those
of reactions with morpholine. The yield of 3a–3c is 50,
68, and 81%, respectively. Saturated NaHCO3 was found
unsatisfactory for the synthesis of 2a–2c and 3a–3c. A
brief survey of base catalysts revealed that diethylamine
has an infuence in the outcome of the reaction. To fnd
best combination of diethylamine with solvent, a number
of solvents which less or more polar than ethanol were
tested. The screening of solvents revealed that ethanol is
the most efective solvent (Table 5, entries 1, 7, and 13).
Attempts to one-pot synthesis of 3a–3c via reaction of
1a–1c with malononitrile and selenium in ethyl alcohol
at room temperature (Table 3) were also successful and
gave the highest yields when the molar ratio of 1a–1c:
malonitrile: Se is 0.75:1.0:1.0 (Table 3, entries 3, 7, and
11). Adjustment of the molar ratio of 1a–1c from 1.0 to
0.75 increased the yield of corresponding coumarin–sele-
nophenes to 65, 72, and 48%, respectively. Nevertheless,
1 3

M. Erşatır et al.
Table 3 Optimization studies of one-pot synthesis of 3a–3c
Entry
Compound
Mol ratio
Yield/%
(3:malononitrile)
1
2
3
4
5
6
7
8
3a
3a
3a
3a
3b
3b
3b
3b
3c
3c
3c
3c
1.0:1.0
0.9:1.0
0.75:1.0
05:1.0
1.0:1.0
0.9:1.0
0.75:1.0
05:1.0
1.0:1.0
0.9:1.0
0.75:1.0
05:1.0
50
53
65
46
58
60
72
56
41
43
48
33
9
10
11
12
Table 4 Optimization studies of the synthesis of 3a–3c with cou-
marin-malononitrile derivatives 2a–2c with diferent bases in EtOH
Antiproliferative activity
The principal interest of this study is synthesis and bio-
logical evaluation of coumarin derivatives with and
without selenophene unit on lactone moiety of coumarin
molecules. In this respect, eight novel coumarin–2-amin-
oselenophene-3-carbonitrile derivatives and eight their
corresponding coumarins were investigated to determine
their potency against to MCF-7 breast cancer cell line and
to measure antioxidant activity. To investigate the antipro-
liferative activity of these novel coumarin–2-aminosele-
nophene-3-carbonitrile derivatives, all compounds were
screened against MCF-7 breast cancer cell line in compari-
son with the activity of the known anti-cancer reference
drug 5-fourouracil (5-FU), and the results are summarized
in Table 6, Figs. 2 and 3.
Entry
Compound
Catalyst
Time/h
Yield/%
1
2
3
4
5
6
7
8
3a
3a
3a
3b
3b
3b
3c
3c
3c
2a
2a
2a
2b
2b
2b
2c
2c
2c
DEA
5
5
5
5
5
5
5
5
5
2
4
8
3
3
8
1
1.5
8
50
38
None
68
52
None
81
70
Trace
93
80
20
78
72
15
98
88
23
Morpholine
Saturated NaHCO3
DEA
Morpholine
Saturated NaHCO3
DEA
Morpholine
Saturated NaHCO3
DEA
Morpholine
Saturated NaHCO3
DEA
Morpholine
Saturated NaHCO3
DEA
Morpholine
Saturated NaHCO3
9
10
11
12
13
14
15
16
17
18
This cell line was selected as many clinical trials show-
ing the activity of selenium compounds in the reduction of
hormone dependent cancer [21, 22]. Doses were chosen
from the results of previous studies [16]. These compounds
were applied for a period 0–48 h. At the end of incubation,
antiproliferative activity was measured with xCELLigence
system. Control cell, not containing compounds. In Figs. 4
and 5, given values show the mean and standard deviation
from three independent experiments carried out in triplicate.
The number of surviving cells decreased as the incubation
1 3

Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and…
Table 5 Optimization studies of the synthesis of 3a–3c with coumarin-malononitrile derivatives 2a–2c in diferent solvents
Entry
Compound
Solvent
Catalyst
Yield/%
1
2
3
4
5
6
7
8
3a
3a
3a
3a
3a
3a
3b
3b
3b
3b
3b
3b
3c
3c
3c
3c
3c
3c
EtOH
MeOH
Ethylene glycol
Toluene
2-Propanol
DCM
EtOH
MeOH
Ethylene glycol
Toluene
2-Propanol
DCM
EtOH
MeOH
Ethylene glycol
Toluene
2-Propanol
DCM
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
DEA
50
33
10
None
None
None
68
47
18
None
None
None
81
60
29
None
None
None
9
10
11
12
13
14
15
16
17
18
Table 6 In vitro cytotoxic
activities of coumarins
Coumarin-sele-
IC50/µM
cLogPa
Coumarins
IC50/µM
cLogPa
nophenes
1a–1h and their corresponding
coumarin-selenophene
3a
3b
3c
3d
3e
3f
11.73 0.41
41.42 1.1
10.83 0.53
46.31 0.76
12.21 0.80
15.18 0.65
40.21 0.48
34.68 1.34
2.32
2.58
3.18
2.46
2.06
4.05
3.03
3.98
1a
1b
1c
1d
1e
1f
85.45 1.91
87.02 1.32
43.91 0.82
93.05 0.88
65.74 0.99
25.20 0.49
94.15 1.68
65.56 0.70
1.15
1.24
2.02
1.14
0.91
2.89
1.87
2.64
derivatives 3a–3h against to
MCF-7 breast cancer cell line
after 48 h treatment
3g
3h
1g
1h
Values are the mean SD. All experimentes were performed three times
acLogP value of the synthesized compounds (calculated from ChemBioDrawUltra 12.0.3)
time increased for coumarins 1a–1h and 3a–3h. It is also
clear that cell viability rate is lower for 3a–3h.
in inhibiting the MCF-7 breast cancer cells with IC50 val-
ues ranging from 10.84 to 46.32 µM. Among them, 3c,
3a, and 3e exhibited potent antiproliferative activity with
values of IC50 (10.84, 11.74, and 12.21 µM, respectively)
better than that of 5-FU (IC50 = 13.5 µM) in breast cancer
MCF-7 cells (Fig. 4).
The cytotoxic activities of tested compounds coumarin
1a–1h and coumarin–selenophenes 3a–3h were expressed
as IC50. In general, all novel coumarin–2-aminosele-
nophene-3-carbonitrile derivatives 3a–3h were efective
1 3

M. Erşatır et al.
Coumarin-selenophene compounds 3a-3h (10 µg/cm3)
Fig. 2 Anti-cancer activity of
coumarin–2-aminoselenophene-
3-carbonitrile derivatives in
comparison with control
120
100
80
60
40
20
0
28.59
83.57
78.30
100
100
23.79
26.31
15.11
71.64
65.79
73.31
78.23
12.07
26.59 69.30
24 H
15.16 64.28
21.28
48 H
Incubaꢀon period /h
Control
3a
3b
3c
3d
3e
3f
3g
3h
Coumarin compounds 1a-1h (10 µg/cm3)
Fig. 3 Anti-cancer activity of
coumarin derivatives in com-
parison with control
120
100
80
60
40
20
0
100
100
88.30
70.08
69.21
77.43
81
61.74
61.25
75
66.96
58.55
58.26
71
62.34
59.00
54.92
51.30
24 h
48 h
Incubaꢀon period /h
Control
1a
1b
1c
1d
1e
1f
1g
1h
Fig. 4 The most potent coumarin–selenophene compounds to MCF-7 breast cancer cell line
Regarding the activity of coumarins 1a–1h against
MCF-7 breast cancer cell line, all of the tested molecules
showed a slight antitumor activity with IC50 values ranging
from 25.20 to 94.15 µM. The results in Table 6 showed that
only 1f possessed slightly cytotoxicity with IC50 =25.20 µM.
Antitumor activity of all tested coumarins 1a–1h was lower
than that of 5-FU (IC50 =13.5 µM) in breast cancer MCF-7
cells. The activity of the tested coumarin derivatives 1a–1h
1 3

Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and…
Fig. 5 Comparing the activity of two most potent coumarin–selenophene compounds with their corresponding coumarins against resistant
MCF-7 breast cancer cell line
against to MCF-7 breast cancer cell line had following
decreasing order: 1f>1c>1 h>1e>1a>1b>1d>1g.
When coumarin derivatives 1a–1h were compared
with their corresponding coumarin–selenophenes, cou-
marin–selenophenes are the most potent candidate to sup-
press cancer cells proliferation in vitro (Fig. 5).
substituent on C-3 of coumarin unit is also more efective to
resist to MCF-7 breast cancer cell line (Fig. 6).
It is also interesting that the most optimal compound
against to breast-cancer cell lines belong to the 3c which
have Br on C-6 and 2-amino-3-cyanoselenophen-5-yl sub-
stituent on C-3 has four times better activity to MCF-7 breast
cancer cell line than its corresponding coumarin 1c. This
clearly indicates the importance of 2-amino-3-cyanosele-
nophen-5-yl substituent on C-3 on coumarin moiety. On the
other hand, the introduction of N,N-diethyl, –OH, –OCH3 on
C-7 did not increase antiproliferative activity against MCF-7
cell line (Table 6).
In previous studies, it was reported that coumarin deriva-
tives show strong activity in the presence of electron with-
drawing groups at C-6 of coumarin moiety. To develop
potent anti-cancer agents, Nasr et al. synthesized sixteen
coumarin derivatives and evaluated them against three dif-
ferent human carcinoma cell lines and found out that 6-bro-
minated coumarin derivatives have signifcant cytotoxicity
against all tested cells [23]. In addition, 6-nitro substituted
coumarins show potent activity to MCF-7 breast cancer cell
line [24]. It is also reported that substituents at position C-3,
C-4, or C-7 of the coumarin core enhance biological activi-
ties, and they are recognized to bring apoptosis in leukemic
cells [25]. In our study, the SAR (structure–activity relation-
ship) result showed that 2-amino-3-cyanoselenophen-5-yl
Antioxidant activity
Antioxidant compounds which scavenge free radicals
have an important role in human life. Hence, we investi-
gated antioxidant activity of sixteen novel biheterocyclic
coumarins along with antiproliferative activity. DPPH
(1,1-diphenyl-2-picrylhydrazyl) method was used to test
Fig. 6 SAR of coumarin–
2-aminoselenophene-3-carboni-
trile derivatives
1 3

M. Erşatır et al.
the compounds. The method measures antioxidant activity
by using stable free radical α,α-diphenyl-β-picrylhydrazyl
(DPPH) [26]. Comparation of the scavenging capacity of
coumarin–selenophenes 3a–3h and coumarins 1a–1h was
carried out against ascorbic acid, as a standard material.
Reduction of stable DPPH radical by of coumarin–sele-
nophenes 3a–3h and coumarins 1a–1h was observed
changing the purple-colored solution into yellow-colored
diphenylpicrylhydrazine. In the presence of hydrogen-
donating antioxidant compounds, radical DPPH was
reduced to non-radical DPPH-H form. The results are
given Table 7.
were even more potent than the standard drug 5-FU. The
most potent compounds in this study were 3c, 3a, and 3e.
Experimental
All the reagents were obtained from diferent commercial
sources. Unless noted otherwise, all of compounds were
used as provided without further purifcation. Ethyl ace-
toacetate (≥ 99%), salicylaldehyde (≥98%), diethylamine
(≥99.5%), dicyanomethane (≥99%), morpholine (≥99%),
selenium powder (− 100 mesh 99.99% trace metals basis),
NaHCO3 (≥99.7%) 5-bromosalicylaldehyde (98%), 4-meth-
oxysalicylaldehyde (98%), 5-nitrosalicylaldehyde (98%),
5-chlorosalicylaldehyde (98%), 3,5-dibromosalicylalde-
hyde (98%), 4-(N,N-diethylamino)salicylaldehyde (98%)
were purchased from Sigma Aldrich. Ethanol (absolute),
methanol (anhydrous, ≥ 99.8%), ethylene glycol (99.8%),
toluene (anhydrous, 99.8%), 2-propanol (anhydrous, 99.5%),
dichloromethane (anhydrous,≥99.8%), hexane (anhydrous,
95%), ethyl acetate (anhydrous, 99.8%) were purchased
from Merck. Follow up of the reactions and checking the
purity of the compounds were made by TLC on silica gel-
precoated aluminum sheets (Type 60, F254, Merck, Darm-
stadt, Germany) using hexane/ethyl acetate (4:1, v/v) and the
spots were detected by exposure to UV lamp at λ=254 nm
for few seconds. Melting points were determined using
an Electrothermal 9100 instrument (United Kingdom) in
open capillary tubes. IR spectra were recorded on a Perkin-
Generally all coumarin–selenophenes 3a–3h and cou-
marins 1a–1h showed good to moderate antioxidant activ-
ity. While there was poor correlation between the antioxi-
dant activity and the antiproliferative activity, 3a is still
the most active one among all the tested compounds. It
was too clear that coumarin–2-aminoselenophene-3-car-
bonitrile backbone is very important for biological activity
(Table 7). When looking at the results of antioxidant activ-
ity, coumarin–selenophene compounds showed inhibition
in the range of 75.82–91.28%, while the compound of cou-
marins showed inhibition in the range of 61.11–89.14%.
The compounds with the highest inhibitory efect in cou-
marin–selenophene compounds were 3a (91.28%) and 3d
(90.58%), while coumarin compounds were 1e (89.14%)
and 1h (86.94%).
1
Elmer 55148 spectrometer (USA) using KBr pellets. H
Conclusion
and 13C NMR spectra were recorded in CDCI3 or DMSO-
d6 using the solvent peak as internal reference (DMSO-d6:
δH =2.50 ppm, δC =39.51 ppm; CDCl3 at 7.27 ppm for 1H
and 77.0 ppm for 13C) on a Bruker 300 MHz Ultrashield TM
spectrometer (Germany) operating at 300 MHz and 75 MHz,
respectively or a Bruker Avance III 400 MHz spectrometer
(Germany) operating at 400 MHz and 100 MHz, respec-
tively. All chemical shift values are quoted in ppm and cou-
pling constants quoted in Hz. Multiplicities are indicated,
s (singlet), d (doublet), t (triplet), q (quartet), sept (septet),
m (multiplet), br s (broad singlet). Elemental analyses were
measured on a Thermo Flash 2000 Organic Elemental Ana-
lyzer (USA).
In conclusion, all synthesized coumarin–selenophenes had
antitumor activity against breast cancer MCF-7 cells. It
can be suggested that the coumarin–2-aminoselenophene-
3-carbonitrile backbone may be an interesting antitumor
pharmaphore, moreover some coumarin–selenophenes
Table 7 Antioxidant activities of coumarins 1a–1h and their corre-
sponding coumarin-selenophene derivatives 3a–3h
Coumarin-sele- Inhibition/%
nophenes
Coumarins
Inhibition/%
3a
3b
3c
3d
3e
3f
91.28
82.28
82.52
90.58
85.47
84.87
87.44
75.82
1a
1b
1c
1d
1e
1f
64.45
61.11
64.86
80.00
89.14
86.39
78.51
86.94
Synthesis of 3‑acetylcoumarin derivatives 1a–1h
A round-bottom fask equipped with a magnetic stirrer was
charged with salicylaldehyde derivative (10 mmol), ethyl-
acetoacetate (10 mmol), and diethylamine (10% w/w). After
the solid formation, the mixture was washed with dilute HCl
to neutralization of waste of base then ethanol was added.
Synthesized 3-acetylcoumarin derivative was crystallized
3g
3h
1g
1h
1 3

Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and…
from ethanol. The product was identifed using FT-IR and
2‑[1‑(6‑Nitro‑2‑oxo‑2H‑chromen‑3‑yl)ethylidene]malononi‑
NMR spectroscopy.
trile (2e, C14H7N3O4) Orange solid; yield 1.940 g (69%); m.p.:
139–141 °C; Rf: 0.33 (hexane/ethyl acetate 4:1 v/v); FT-IR
(KBr): ꢀ = 3016 (C–H, aromatic), 2995 (C–H, aliphatic),
2197 (CN), 1702 (C=O), 1602, 1523 (C=C, aromatic), 1276
(C–N), 1201 (C–O) cm−1; 1H NMR (400 MHz, DMSO-d6):
δ=8.23 (d, J=7.6 Hz, 1H, Ar–H), 8.11 (s, 1H,=CH), 7.99
(d, J=7.6 Hz, 1H, Ar–H), 7.12 (s, 1H, Ar–H), 2.51 (s, 3H,
CH3) ppm; 13C NMR (100 MHz, DMSO-d6): δ = 177.32,
158.10, 142.21, 132.80, 127.85, 125.66, 125.11, 120.92,
109.67, 86.68, 10.98 ppm.
3‑Acetyl‑6,8‑dibromo‑2H‑chromen‑2‑one (1f, C11H6Br2O3)
Red solid; yield 2.802 g (81%); m.p.: 163–165 °C; Rf: 0.35
(hexane/ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3061, 3045
(C–H, aromatic), 2995 (C–H, aliphatic), 1725 (C=O), 1681
(C=O), 1599, 1539 (C=C, aromatic), 1204 (C–O), 554
1
(C–Br) cm−1; H NMR (400 MHz, CDCl3): δ = 8.36 (s,
1H,=CH), 7.99 (s, 1H, Ar–H), 7.27 (s, 1H, Ar–H), 2.73 (s,
3H, CH3) ppm; 13C NMR (100 MHz, CDCl3): δ=194.42,
158.00, 145.62, 139.55, 134.20, 131.41, 130.14, 125.89,
121.38, 118.66, 30.45 ppm.
2‑[1‑(6,8‑Dibromo‑2‑oxo‑2H‑chromen‑3‑yl)ethylidene]malo‑
nonitrile (2f, C14H6Br2N2O2) Red solid; yield 2.837 g (72%);
m.p.: 198–200 °C; Rf: 0.30 (hexane/ethyl acetate 4:1 v/v);
FT-IR (KBr): ꢀ =3061 (C-H, aromatic), 2998, 2966 (C–H,
aliphatic), 2194 (CN), 1727 (C=O), 1601, 1539 (C=C,
aromatic), 1238 (C–N), 1206 (C–O), 557 (C–Br) cm−1; 1H
NMR (400 MHz, DMSO-d6): δ=8.58 (s, 1H,=CH), 8.26 (s,
Synthesis of coumarinyl malononitrile compounds
2a–2h
A mixture of 3-acetylcoumarin derivatives (10 mmol), malo-
nonitrile (10 mmol), catalytic amount of diethylamine and
25 cm3 ethanol were stirred at RT for 1–4.5 h. The reaction
was monitored by TLC. After completion of the reaction,
as shown by disappearance of 3-acetylcoumarin deriva-
tive, the mixture was poured into 20 cm3 ice-cold water.
The separated solid was fltered, washed with water (3×10
cm3), and dried. The crude product was recrystallized from
ethanol. The product was identifed using FT-IR and NMR
spectroscopy.
1H, Ar–H), 7.63 (s, 1H, Ar–H), 2.59 (s, 3H, CH3) ppm; 13
C
NMR (100 MHz, DMSO-d6): δ = 176.62, 157.29, 150.44,
138.36, 132.17, 130.40, 125.99, 121.04, 116.37, 110.03,
88.30, 11.00 ppm.
2‑[1‑(6‑Chloro‑2‑oxo‑2H‑chromen‑3‑yl)ethylidene]malo‑
nonitrile (2g, C14H7ClN2O2) Yellow solid; yield 2.138 g
(79%); m.p.: 185–187 °C; Rf: 0.46 (hexane/ethyl acetate 4:1
v/v); FT-IR (KBr): ꢀ =3041 (C–H, aromatic), 2995 (C–H,
aliphatic), 2190 (CN), 1737 (C=O), 1593, 1549 (C=C,
aromatic), 1230 (C–N), 1200 (C–O), 565 (C–Cl) cm−1; 1H
NMR (400 MHz, DMSO-d6): δ = 8.21 (s, 1H, =CH), 7.54
(s, 1H, Ar–H), 7.32 (d, J = 7.6 Hz, 1H, Ar–H), 7.08 (d,
J = 7.6 Hz, 1H, Ar–H), 2.51 (s, 3H, CH3) ppm; 13C NMR
(100 MHz, DMSO-d6): δ=177.18, 161.73, 154.09, 132.45,
131.89, 129.51, 128.00, 127.08, 118.99, 116.28, 77.87,
11.08 ppm.
2‑[1‑(7‑Methoxy‑2‑oxo‑2H‑chromen‑3‑yl)ethylidene]malon‑
onitrile (2b, C15H10N2O3) Yellow solid; yield 2.077 g (78%);
m.p.: 170–172 °C; Rf: 0.57 (hexane/ethyl acetate 4:1 v/v);
FT-IR (KBr): ꢀ = 3042 (C–H, aromatic), 2995 (C–H, ali-
phatic), 2226 (CN), 1719 (C=O), 1604, 1577 (C=C, aro-
matic), 1285 (C–N), 1237 (C–O) cm−1; 1H NMR (400 MHz,
DMSO-d6): δ=8.46 (s, 1H,=CH), 7.76 (d, J=11.6 Hz, 1H,
Ar–H), 7.11 (d, J=3.2 Hz, 1H, Ar–H), 7.06–7.03 (m, 1H,
Ar–H), 3.91 (s, 3H, OCH3), 2.59 (s, 3H, CH3) ppm; 13C
NMR (100 MHz, DMSO-d6): δ = 172.77, 165.03, 157.45,
156.55, 132.63, 131.56, 120.22, 114.12, 113.04, 112.82,
111.87, 101.16, 86.73, 56.78, 23.45 ppm.
Synthesis of coumarin–2‑aminoselenophene‑3‑
carbonitrile derivatives 3a‑3 h
2‑[1‑(7‑Hydroxy‑2‑oxo‑2H‑chromen‑3‑yl)ethylidene]malon‑
onitrile (2d, C14H8N2O3) Yellow solid; yield 2.018 g (80%);
m.p.: 238–240 °C; Rf: 0.52 (hexane/ethyl acetate 4:1 v/v);
FT-IR (KBr): ꢀ =3308 (OH), 3090 (C–H, aromatic), 2986
(C–H, aliphatic), 2202 (CN), 1693 (C=O), 1613, 1562
(C=C, aromatic), 1256 (C–N), 1192 (C–O) cm−1; 1H NMR
(400 MHz, DMSO-d6): δ = 8.24 (s, 1H, =CH)), 7.88 (d,
J=11.6 Hz, 1H, Ar–H), 7.65 (d, J=11.6. Hz, 1H, Ar–H),
6.81–6.70 (m, 1H, Ar–H), 4.52 (br s, 1H), 2.51 (s, 3H, CH3)
ppm; 13C NMR (100 MHz, DMSO-d6): δ=170.96, 162.85,
162.17, 156.77, 138.63, 131.75, 126.17, 111.32, 108.84,
102.28, 102.10, 75.51, 11.73 ppm.
A mixture of arylidene malononitrile (5 mmol), selenium
(5 mmol), 15 cm3 ethanol, and catalytic amount of diethyl-
amine was stirred at RT for 3–7 h. The reaction was moni-
tored by TLC. After completion of reaction, as shown by
disappearance of arylidene malononitrile, unreacted sele-
nium was fltered and the mixture was poured into 40 cm3
ice-cold water. The separated solid was fltered, washed
with water (3 × 20 cm3), and dried. The crude product was
recrystallized from ethanol. The product was identifed
using FT-IR and NMR spectroscopy.
1 3

M. Erşatır et al.
133.00, 131.28, 128.42, 120.53, 119.17, 118.87, 116.82,
90.37 ppm.
One pot synthesis of coumarin–2‑aminoselenophene‑3‑
carbonitrile derivatives 3a–3h
2‑Amino‑5‑(7‑hydroxy‑2‑oxo‑2H‑chromen‑3‑yl)sele‑
nophene‑3‑carbonitrile (3d, C14H8N2O3Se) Black solid; yield
0.878 g (72%); m.p.:>250 °C; Rf: 0.45 (hexane/ethyl acetate
4:1 v/v); FT-IR (KBr): ꢀ = 3349 (OH), 3152 (NH2), 3075
(C–H, aromatic), 2980 (C–H, aliphatic), 2166 (CN), 1729
(C=O), 1601, 1472 (C=C, aromatic), 1232 (C–N), 1153
(C–O) cm−1; 1H NMR (400 MHz, DMSO-d6): δ=8.55 (s,
2H, NH2), 7.71–7.66 (m, 2H, Ar–H), 7.18 (d, J=6.0 Hz, 1H,
Ar–H), 6.95 (s, 1H,=CH)), 6.49 (s, 1H, Ar–H), 5.14 (br s,
1H, OH) ppm; 13C NMR (100 MHz, DMSO-d6): δ=159.93,
158.50, 158.06, 148.96, 145.09, 132.89, 131.91, 127.89,
115.28, 113.96, 112.68, 112.45, 103.77, 91.91 ppm.
A mixture of 3-acetylcoumarin derivative (5 mmol), malo-
nonitrile (5 mmol), selenium (5 mmol), 15 cm3 ethanol, and
catalytic amount of diethylamine was stirred at RT for 7 h.
The reaction was monitored by TLC. After completion of
reaction, unreacted selenium was fltered and 15 cm3 ethyl
acetate was added, and the reaction mixture was washed with
water (3×15 cm3). The organic layer was dried over anhy-
drous sodium sulfate and concentrated to dryness, the crude
product was recrystallized from ethanol. The pure products
were identifed using FT-IR and NMR spectroscopy.
2‑Amino‑5‑(2‑oxo‑2H‑chromen‑3‑yl)selenophene‑3‑car‑
bonitrile (3a, C14H8N2O2Se) Brown solid; yield 0.788 g
(50%); m.p.: 244–246 °C; Rf: 0.41 (hexane/ethyl acetate 4:1
v/v); FT-IR (KBr): ꢀ =3201 (NH2), 3071 (C–H, aromatic),
2988 (C–H, aliphatic), 2178 (CN), 1702 (C=O), 1605,
1456 (C=C, aromatic), 1215 (C–N), 1198 (C–O) cm−1; 1H
NMR (400 MHz, DMSO-d6): δ = 8.35 (s, 2H, NH2), 7.98
(d, J=7.6 Hz, 1H, Ar–H), 7.69 (t, J=8.4 Hz, 1H, Ar–H),
7.45 (d, J=7.6 Hz, 1H, Ar–H), 7.40 (s, 1H,=CH), 7.14 (t,
J=7.6 Hz, 1H, Ar–H), 7.05 (s, 1H, Ar–H) ppm; 13C NMR
(100 MHz, DMSO-d6): δ=160.41, 156.95, 152.71, 152.63,
140.59, 132.43, 130.11, 129.40, 129.06, 124.90, 118.46,
116.41, 115.87, 113.96, 86.16 ppm.
2‑Amino‑5‑(6‑nitro‑2‑oxo‑2H‑chromen‑3‑yl)sele ‑
nophene‑3‑carbonitrile (3e, C14H7N3O4Se) Brown solid;
yield 0.522 g (51%); m.p.: 129–131 °C; Rf: 0.27 (hexane/
ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3204 (NH2), 3013
(C–H, aromatic), 2998 (C–H, aliphatic), 2195 (CN), 1701
(C=O), 1614, 1513 (C=C, aromatic), 1246 (C–N), 1221
1
(C–O) cm−1; H NMR (400 MHz, DMSO-d6): δ = 8.29
(s, 2H, NH2), 7.89 (d, J = 7.2 Hz, 1H, Ar–H), 7.72 (dd,
J=10.8 Hz, 2.4 Hz, 1H, Ar–H), 7.23 (s, 1H,=CH)), 7.18 (s,
1H, Ar–H), 6.98 (s, 1H, Ar–H) ppm; 13C NMR (100 MHz,
DMSO-d6): δ = 161.83, 158.47, 153.05, 143.11, 140.48,
129.65, 124.64, 124.58, 123.55, 122.06, 118.13, 116.84,
114.10, 94.38 ppm.
2‑Amino‑5‑(7‑methoxy‑2‑oxo‑2H‑chromen‑3‑yl)sele‑
nophene‑3‑carbonitrile (3b, C15H10 N2O3Se) Brown solid;
yield 1.001 g (68%); m.p.: 187–189 °C; Rf: 0.52 (hexane/
ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3214 (NH2), 3015
(C–H, aromatic), 2995 (C–H, aliphatic), 2197 (CN), 1702
(C=O), 1654, 1513 (C=C, aromatic), 1276 (C–N), 1201
(C–O) cm−1; 1H NMR (400 MHz, DMSO-d6): δ=8.47 (s,
2H, NH2), 7.86 (s, 1H, Ar–H), 7.78 (s, 1H, Ar–H), 7.76
(s, 1H, =CH), 7.12 (d, J = 3.2 Hz, 1H, Ar–H), 7.07 (d,
J=3.6 Hz, 1H, Ar–H), 7.05 (t, J=4.4 Hz, 1H, Ar–H), 3.91
(s, 3H, OCH3) ppm; 13C NMR (100 MHz, DMSO-d6):
δ=165.04, 157.46, 156.55, 146.06, 131.57, 120.81, 120.23,
114.13, 113.05, 112.82, 111.88, 101.18, 86.72, 56.80 ppm.
2‑Amino‑5‑(6,8‑dibromo‑2‑oxo‑2H‑chromen‑3‑yl)sele‑
nophene‑3‑carbonitrile (3f, C14H6Br2N2O2Se) Brown solid;
yield 0.828 g (59%); m.p.: 225–227 °C; Rf: 0.25 (hexane/
ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3205 (NH2), 3022
(C–H, aromatic), 2992 (C–H, aliphatic), 2193 (CN), 1706
(C=O), 1625, 1523 (C=C, aromatic), 1276 (C–N), 1198
1
(C–O), 535 (C–Br) cm−1; H NMR (400 MHz, DMSO-
d6): δ = 8.22 (s, 2H, NH2), 8.08 (s, 1H, Ar–H), 7.58 (s,
1H,=CH), 6.75 (s, 1H, Ar–H), 6.12 (s, 1H, Ar–H) ppm; 13
C
NMR (100 MHz, DMSO-d6): δ = 158.94, 152.00, 145.27,
142.92, 137.99, 131.09, 126.28, 125.42, 125.34, 120.22,
117.69, 114.42, 114.07, 90.42 ppm.
2‑Amino‑5‑(6‑bromo‑2‑oxo‑2H‑chromen‑3‑yl)sele‑
nophene‑3‑carbonitrile (3c, C14H7BrN2O2Se) Brown solid;
yield 0.808 g (81%); m.p.: 212–214 °C; Rf: 0.29 (hexane/
ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3210 (NH2), 3056
(C–H, aromatic), 2991 (C–H, aliphatic), 2196 (CN), 1728
(C=O), 1598, 1553 (C=C, aromatic), 1234 (C–N), 1181
2‑Amino‑5‑(6‑chloro‑2‑oxo‑2H‑chromen‑3‑yl)sele‑
nophene‑3‑carbonitrile (3g, C14H7ClN2O2Se) Yellow solid;
yield 0.682 g (55%); m.p.:>250 °C; Rf: 0.41 (hexane/ethyl
acetate 4:1 v/v); FT-IR (KBr): ꢀ =3201 (NH2), 3020 (C=C,
aromatic), 2994 (C–H, aliphatic), 2191 (CN), 1700 (C=O),
1610, 1508 (C=C, aromatic), 1270 (C–N), 1202 (C–O), 593
(C–Cl) cm−1; 1H NMR (400 MHz, DMSO-d6): δ=8.58 (s,
2H, NH2), 8.23 (s, 1H, Ar–H), 8.06 (s, 1H, Ar–H), 7.68
(d, J=8.8 Hz, 1H, Ar–H), 7.39 (d, J=8.8 Hz, 1H, Ar–H),
7.11 (s, 1H,=CH) ppm; 13C NMR (100 MHz, DMSO-d6):
1
(C–O), 1069, 663 (C–Br) cm−1; H NMR (400 MHz,
DMSO-d6): δ = 8.61 (s, 2H, NH2), 8.15 (s, 1H, Ar–H),
7.59 (s, 1H, Ar–H), 7.51 (s, 1H,=CH), 7.46 (d, J=4.8 Hz,
1H, Ar–H), 7.43 (d, J=4.8 Hz, 1H, Ar–H) ppm; 13C NMR
(100 MHz, DMSO-d6): δ=160.13, 152.81, 140.67, 137.20,
1 3

Synthesis and antiproliferative evaluation of novel biheterocycles based on coumarin and…
δ=157.55, 155.45, 151.63, 142.17, 133.70, 126.31, 125.26,
methanol was used as blank. The DPPH radical scaveng-
122.66, 118.65, 117.35, 115.64, 94.21 ppm.
ing activity was determined by measuring the absorbance
at 517 nm using the UV–Vis spectrophotometer (Thermo
scientifc-USA). The DPPH radical scavenging activity of
ascorbic acid was also assayed for comparison. The percent-
age of DPPH radical scavenger was calculated using Eq. (1):
2‑Amino‑5‑[7‑(N,N‑diethylamino)‑2‑oxo‑2H‑chromen‑3‑
yl]selenophene‑3‑carbonitrile (3h, C18H17N3O2Se) Black solid;
yield 0.637 g (50%); m.p.: 148–150 °C; Rf: 0.46 (hexane/
ethyl acetate 4:1 v/v); FT-IR (KBr): ꢀ =3223 (NH2), 3056
(C–H, aromatic), 2995, 2888 (C–H, aliphatic), 2199 (CN),
1702 (C=O), 1628, 1505 (C=C, aromatic), 1286 (C–N),
[(
/
)
]
Radical scavenging activity (%) = A0 − A1 A0 × 100
(1)
1
1209 (C–O) cm−1; H NMR (400 MHz, CDCl3): δ = 9.48
where A0 is the absorbance of the control reaction and A1 is
(s, 2H, NH2), 8.68 (s, 1H, Ar–H), 7.27 (d, J=7.2 Hz, 1H,
Ar–H), 6.48 (s, 1H,=CH), 6.21 (dd, J=11.2 Hz, 2.4 Hz, 1H,
Ar–H), 6.07 (s, 1H, Ar–H), 3.40 (q, J=7.2 Hz, 4H, 2 CH2),
1.21 (t, J=7.2 Hz, 6H, 2 CH3) ppm; 13C NMR (100 MHz,
CDCl3): δ=164.40, 154.26, 148.82, 147.87, 135.38, 131.90,
131.32, 123.40, 117.48, 111.43, 110.04, 104.40, 96.70,
44.81, 12.57 ppm.
the absorbance in the presence of the samples or standards.
Acknowledgements The authors are greatly thankful to the Scientifc
and Technical Research Council of Turkey (TUBITAK) for a schol-
arship to Mehmet Erşatır and for the support of Scientifc Research
Committee of Cukurova University (FDK-2017-8591).
Funding Funding was provided by Çukurova Üniversitesi (Grant No.
FDK-2017-8591) and TÜBİTAK (Grant No. 2211-A).
Antiproliferative activity
Human breast cancer cell line MCF-7 was obtained from
HUKUK WDCM756: Culture Collection of Animal Cells,
Foot and Mouth Disease Institute (ANKARA-TURKEY).
Cells were routinely cultivated in RPMI 1640 supplemented
with 10% fetal bovine serum, penicillin (100 U/cm3) and
streptomycin (100 mg/cm3) at 37 °C and 5% CO2 [5]. In
current study, xCELLigence system (ACEA) (USA) used
to monitor cytotoxicity, using electronic cell sensor array
technology.
References
1. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D (2011)
Cancer J Clin 61:69
2. Ferlay J, Shin HR, Bray F, Forman D, Mathers CD, Parkin D
(2008) Int J Cancer 127:2893
3. Liu Y, Zhang S, Abreu PJM (2006) Nat Prod Rep 23:630
4. Hughes RA, Moody CJ (2007) Angew Chem Int Ed 46:7930
5. Ganina OG, Daras E, Bourgarel-Rey V, Peyrot V, Andresyuk AN,
Finet JP, Fedorov AY, Beletskaya IP, Combes S (2008) Bioorg
Med Chem 16:8806
5-Fluorouracil (5-Fu) was purchased from Sigma-
Aldrich. 5-FU as the positive control was dissolved in RPMI
culture medium and further concentrations of 15, 4.5, 1.35,
0.4, 0.12 μg/cm3 were prepared. Tested were dissolved in
DMSO at 1 mg/cm3 immediately before using and diluted
to the appropriate volume just before adding to the cell cul-
ture. xCELLigence E-plates were flled with 0.1 cm3 RPMI
medium/well and the background signal was determined.
Then, 0.1 cm3 of cell suspension was added in to each well
(3×104 cells/well). Thereafter, positive control and tested
cytostatics according to selected concentration ranges (0,
5, 10, 15, 20, 50 μg/cm3) were added to cultivation media
and cell index was recorded for next 48 h. IC50 values were
determined for each cytostatic after 48 h of treatment [18].
6. Arshad A, Osman H, Bagley MC, Lam CK, Mohamad S, Zahari-
luddin ASM (2011) Eur J Med Chem 46:3788
7. Gali R, Banothu J, Gondru R, Bavantula R, Velivela Y, Crooks
PA (2015) Bioorg Med Chem Lett 25:106
8. Delogu G, Picciau C, Ferino G, Quezada E, Podda G, Uriarte E,
Vina D (2011) Eur J Med Chem 46:1147
9. Kurt BZ, Gazioglu I, Sonmez F, Kucukislamoglu M (2015) Bioorg
Chem 59:80
10. Dömötör O, Tuccinardi T, Karcz D, Walsh M, Creaven BS,
Enyedy EA (2014) Bioorg Chem 52:16
11. Musa MA, Latinwo LM, Virgile C, Badisa VLD, Gbadebo AJ
(2015) Bioorg Chem 58:96
12. Reddy DS, Kongot M, Singh V, Maurya N, Patel R, Singhal NK,
Avecilla F, Kumar A (2019) Bioorg Chem 92:103212
13. Zhang S, Wang Z, Hu Z, Li C, Tang C, Carlson KE, Luo J, Dong
C, Katzenellenbogen JA, Huang J, Zhou HB (2017) ChemMed-
Chem 12:235
14. Pelkey ET (2008) Selenophenes. In: Katritzky AR, Ramsden
CA, Scriven EFV, Taylor JKT (eds) Comprehensive heterocyclic
chemistry III. Elsevier, Amsterdam
DPPH radical scavenging activity
15. Müller-Schifmann A, Sticht H, Korth C (2012) BioDrugs 26:21
16. Batran RZ, Dawood DH, El-Seginy SA, Ali MM, Maher TJ, Gug-
nani KS, Rondon-Ortiz AN (2017) Arch Pharm 350:1700064
17. Ayaz F, Kheeree R, Isse Q, Ersan R, Algul O (2018) J Turk Chem
Soc Sect A 5:1145
The DPPH radical scavenging activities of the 3a–3h and
coumarins 1a–1h were evaluated according to Blois method
[26]. Initially, 0.1 cm3 of the samples at concentration of
250, 500, 750, and 1000 μg/cm3 was mixed with 1 cm3 of
0.2 mM DPPH that was dissolved in methanol. The reac-
tion mixture was incubated in the dark for 20 min at 28 °C.
The control contained all reagents without the sample while
18. Jalkh N, Nassar-Slaba J, Chouery E, Salem N, Uhrchammer N,
Golmard L, Mégarbané A (2012) Hered Cancer Clin Pract 10:7
1 3

M. Erşatır et al.
19. Arsenyan P, Vasiljeva J, Domracheva I, Kanepe-Lapsa I, Gulbe A
(2019) New J Chem 43:11851
25. Penta S (2016) Antitumor agents, vol 3. Advances in structure and
activity relationship of coumarin derivatives. Elsevier, Amsterdam
26. Blois MS (1958) Nature 181:1199
20. Arsenyan P, Vasilijeva J, Shestakova I (2015) C R Chim 18:399
21. Chen T, Wong YS (2008) J Agric Food Chem 56:4352
22. Sangsuwan R, Sangher S, Aree T, Mahidol C, Ruchirawat S, Kit-
takoop P (2014) RSC Adv 4:13708
Publisher’s Note Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional afliations.
23. Nasr T, Bondock S, Youns M (2014) Eur J Med Chem 76:539
24. Soni R, Durgapal SD, Soman SS, Georrge JJ (2019) Arabian J
Chem 5:701
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