Visible Light-Induced Synthesis of Biscoumarin Analogs under Catalyst-Free Conditions

Article abstract of DOI:10.1002/jhet.3171

Biscoumarin analogs were synthesized by the reaction between two equivalent of 4-hydroxycoumarin and one equivalent of aryl aldehydes induced by visible light [22?W compact fluorescent lamp (CFL) bulb]. This new method is simple, cost-effective, and furni

Full text of DOI:10.1002/jhet.3171

Month 2018
Visible Light-Induced Synthesis of Biscoumarin Analogs
under Catalyst-Free Conditions
Ankusab Noorahmadsab Nadaf and Kalegowda Shivashankar*
P. G. Department of Chemistry, Central College Campus, Bangalore University, Bangalore 560 001, Karnataka, India
*
E-mail: shivashankark@gmail.com
Received October 31, 2017
DOI 10.1002/jhet.3171
Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com).
Biscoumarin analogs were synthesized by the reaction between two equivalent of 4-hydroxycoumarin and
one equivalent of aryl aldehydes induced by visible light [22 W compact fluorescent lamp (CFL) bulb]. This
new method is simple, cost-effective, and furnished excellent yields with broad substrate generality in short
reaction time.
J. Heterocyclic Chem., 00, 00 (2018).
INTRODUCTION
guanidium [21], phosphotungstic acid [22], nano silica
chloride [23], propane-1,2,3-triyltris(hydrogen sulfate)
[24], choline hydroxide [25], poly(4-vinylpyridine)-
supported ionic liquids [26], ruthenium(III) chloride
hydrate [27], sulfated titania [28], methane sulfonic acid
[29], sodium dodecyl sulfate [30], ruthenium [31], nano
Because of environmental and societal interests, there has
been a great demand for the development of the simple and
environmental benign synthetic methods that minimizes the
use of toxic reagents, catalysts, acids, alkali, and hazardous
solvents [1]. The pursuit of greener and facile synthesis to
prepare various organic compounds continues to be
challenging. Among numerous green methods, the use of
visible light [compact fluorescent lamp (CFL) bulb] has
received much attention.
TiO @KSF [32], silica-bonded n-propyl diethylene
2
triamine sulfamic acid [33], and W-doped ZnO
nanocomposite [34]. However, these methods suffer from
the limitations such as use of expensive, toxic, greater
loading of catalysts, incomplete conversion, and lower
yields. Prompted by the previous points and our
continuous efforts for preparing heterocyclic derivatives
[35–37], we envisioned the catalyst-free synthesis of
biscoumarin derivatives using visible light (CFL bulb)
system at ambient temperature.
To date, no report has described the synthesis of
biscoumarins under CFL light irradiation. CFL light
intensity is harmless and an easily available energy
source. CFL light intensity proved to be a very useful
source in the synthesis of unsymmetrical diynes [38],
cyclocondensation of pyrrole [39], photocatalytic
Biscoumarins are an important class that often display
diverse biological activities [2,3] such as antitumor [4],
anti-inflammatory [5], antioxidant [6], and cytotoxicity
[
7]. These compounds are widely used as ligands [8],
reducing and stabilizing agent [9], dyes [10], etc. Up to
date, many biscoumarin analogs have been discovered
from the natural sources [11] including Dicoumarol
Melilotus alba), Gerberinol (Gerbera lanuginose),
Ismailin (Diospyros ismaili), and Bisosthenon (Citrus
funadokoao) (Fig. 1).
Many synthetic approaches have been reported
for the synthesis of biscoumarins [12–15]. The
most important protocols are from (i) benzylic alcohols
and 4-hydroxycoumarin [16], (ii) 1,2-diols and
-hydroxycoumarin [17], and (iii) benzaldehydes and
-hydroxycoumarin [18]. The last method is of particular
interest, and much development has been progressed.
In the last decades, use of various catalytic conditions
has been established for the preparation of biscoumarins
from 4-hydroxycoumarin and aryl aldehydes such as
molecular iodine [19], Zn(proline)2 [20], tetramethyl
(
generation of H [40], carboxylation [41], synthesis of
2
1,2-diketones [42], trifluromethylated alkenes [43], diaryl
disulfides [44], oxysulfonylation of alkenes [45],
3,4-dithiophenes [46], benzothiazoles [47], photochromic
molecules [48], iron(III)-based metal organic frame works
[49], and photocatalyst [50].
Therefore, the present synthesis of biscoumarins is
novel, highly efficient, cost-effective, environmentally
sustainable, and compatible for catalytic, biomedical, and
industrial applications.
4
4
©
2018 Wiley Periodicals, Inc.

A. N. Nadaf and K. Shivashankar
Vol 000
Figure 1. Some naturally occurring biscoumarins.
RESULTS AND DISCUSSION
and 22 W CFL light intensity were selected as the
optimal reaction condition for further experiments. When
taking 2:1 molar ratio of 4-hydroxycoumarin (2) and
benzaldehyde (1g), which are condensed under visible
light intensity, the target compound (3g) was obtained in
95% yield.
Encouraged by the remarkable optimization results, we
explored the generality and scope of the protocol by
reacting 4-hydroxycoumarin with structurally diverse
aldehydes (Table 2) under optimized conditions. The
reaction effectively proceeded with both electron
donating and electron withdrawing precursors.
Interestingly, hetero aromatic aldehydes such as indole
and thiophene were found to be equally efficient at
yielding the expected products in excellent yields.
In accordance with previous literature reports [50–54], a
plausible radical mechanism is proposed (Scheme 2). It is
proposed that the aldehydes undergo Norrish-type
In order to establish the optimal conditions for the
synthesis of biscoumarins, 4-hydroxycoumarin (2) and
benzaldehyde (1g) were chosen as a model substrate and
allowed to react in the presence of visible light (20 W,
CFL) intensity in DMF at room temperature for 4 h
(
Scheme 1). The presence of visible light intensity was
crucial because, in its absence, the reaction did not
proceed. The initial examination, to our delight, showed
that CFL light intensity can catalyze the model reaction
to afford the (3g) in 46 % yield.
A survey on intensities of light and solvent suggests that
ethanol at 22 W is optimum because its reaction time and
yields are better than those of others (Table 1). When the
temperature was increased from room temperature to
7
8°C (reflux), the time and yield of the reaction was not
improved. Therefore, room temperature, ethanol solvent,
Scheme 1. Synthesis of biscoumarin (3g) under visible light. [Color figure can be viewed at wileyonlinelibrary.com]
Table 1
Optimization of solvent and visible light intensity for the synthesis of (3g).
Entry
Solvent
Cl
Dioxane
Acetonitrile
Toluene
THF
Visible light intensity (W)
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
9
CH
2
2
20
20
20
20
20
20
20
20
20
22
15
8
5.5
6.5
4
4.5
5
3.5
4.0
5.5
2.3
2
3.1
4.2
2
41
78
67
70
72
82
46
52
88
95
77
69
95
Methanol
DMF
DMSO
Ethanol
Ethanol
Ethanol
Ethanol
Ethanol
10
1
1
1
1
2
3
32
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Visible Light-Induced Synthesis of Biscoumarin Analogs under Catalyst-Free
Conditions
Table 2
Visible light-induced synthesis of biscoumarin analogs under optimized condition.
Entry
1
Ar
Product
Time (h)
2
Yield (%)
92
Obs.Mp (°C)
Lit.Mp (°C)
3a
144–146
–
2
3
3b
3c
2.2
2.7
91
91
199–201
255–257
–
–
4
5
3d
3e
2.2
1.9
90
88
212–214
255–257
–
–
(
27)
6
3f
2.8
87
245–247
264–266
(
(
(
12)
12)
12)
7
8
9
3g
3h
3i
2.3
2.5
2.6
2.3
2.5
2.6
2.5
95
96
89
92
96
89
91
228–230
234–236
250–252
259–261
265–267
215–217
242–244
230–231
232–233
251–252
259–260
266–268
214–216
241–243
(
(
(
(
12)
12)
12)
12)
1
0
3j
11
3k
3l
1
1
2
3
3m
(
12)
14
3n
2.8
90
264–266
263–265
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. N. Nadaf and K. Shivashankar
Vol 000
Scheme 2. Plausible free radical mechanism for the synthesis of biscoumarins. [Color figure can be viewed at wileyonlinelibrary.com]
1
13
cleavage and phenolic hydrogen of the 4-hydroxycoumarin
breaks symmetrically to form the radical. These radicals
further react to form the intermediates I, II, and III and
finally gives the stable biscoumarin analogs. To verify
whether the reaction proceeds through radical pathway or
ionic pathway, the same model reaction was performed in
the presence of hydroquinone, which is a radical inhibitor
for H -NMR and 100 MHz for C -NMR) using TMS as
an internal standard in CDCl . Chemical shifts (δ) are
3
measured in ppm. The progress of the reaction and purity
of the compounds were checked by TLC. The elemental
analyses were performed on Elemental Vario Micro Cube
CHN Rapid Analyzer. Philips CFL bulbs are used as a
visible light source.
[55]. Only a trace amount of product (3g) was produced.
General experimental procedure for the synthesis of
This experiment clearly exhibited that the reaction
proceeded via a radical pathway.
biscoumarin derivatives (3a–n).
A
mixture of
arylaldehydes (1 mmol), 4-hydroxycoumarin (2 mmol)
A), and ethanol (10 mL) was taken in a 100-mL
beaker. A glowing CFL bulb (22 W) was placed inside
the beaker but just above (2-cm height) the reaction
mixture. The reaction mixture was stirred at RT for the
time shown in Table 2. The progress of the reaction
was monitored by TLC (Eluent: EtOAc and n-hexane).
The evaporation of solvent in vacuo afforded the crude
product, which was recrystallized from ethanol to
obtain biscoumarins.
CONCLUSION
Eventually, we can conclude that visible light (CFL
bulb, 22 W) can induce reaction between two equivalent
of 4-hydroxy coumarin and one equivalent of aryl
aldehydes to produce biscoumarin derivatives. The
excellent yield, broad substrate profile, short reaction
time, and catalyst free are the merits of this protocol.
SPECTRAL DETAILS
GENERAL INFORMATION
4
-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(2-
The melting points were determined using electric
melting point apparatus and are uncorrected. NMR
spectra were recorded on a Jeol spectrometer (400 MHz
phenyl-1H-indol-3-yl)methyl)-2H-chromen-2-one (3a).
A
1
purple solid; H NMR (CDCl 400 MHz): δ 5.82 (s, 1H,
3
CH), 7.08–7.67 (m, 17H, Ar-H), 8.40 (s, 1H, OH), 8.42
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Visible Light-Induced Synthesis of Biscoumarin Analogs under Catalyst-Free
Conditions
1
3
(
s, 1H, OH), 8.87 (s, 1H, NH) ppm. C NMR (CDCl3
473.6214; Anal. Calcd for C H O C, 68.64; H, 4.27;
27 20 8:
100 MHz): δ 36.0, 110.8, 111.0, 116.7, 122.3, 123.3,
123.5, 124.1, 124.5, 125.1, 129.0, 129.2, 129.5, 130.1,
132.6, 138.2, 144.0, 144.2, 144.5, 144.7, 155.7, 155.9,
165.7, 165.9 ppm. HRMS: [M + H] = m/z 528.6214;
found: C, 68.60; H, 4.24%.
4-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(phenyl)
methyl)-2H-chromen-2-one (3g). A white solid; H NMR
1
(CDCl 400 MHz): δ 6.09 (s, 1H, CH), 7.20–7.64 (m,
3
Anal. Calcd for C H NO : C, 75.13; H, 4.01; N, 2.66;
found: C, 75.10; H, 4.00; N, 2.63%.
13H, Ar-H), 7.98 (s, 1H, OH), 8.05 (s, 1H, OH) ppm.
C NMR (CDCl3 100 MHz): δ 36.1, 105.6, 116.4,
3
3
21
6
13
3
-((5-Bromothiophen-2-yl)(4-hydroxy-2-oxo-2H-chromen-
116.6, 124.4, 124.8, 126.4, 126.8, 128.6, 128.9, 132.8,
135.1, 145.1, 162.8 ppm. HRMS: [M + H] = m/z
413.1645; Anal. Calcd for C H O : C, 72.81; H, 3.91;
3
-yl)methyl)-4-hydroxy-2H-chromen-2-one (3b).
yellow solid; H NMR (CDCl 400 MHz): δ 6.09 (s, 1H,
A light
1
3
25 16 6
CH) 6.60–7.64 (m, 10H, Ar-H), 8.02 (s, 1H, OH), 8.04
found: C, 72.76; H, 3.87%.
1
3
(
s, 1H, OH) ppm. C NMR (CDCl 100 MHz): δ 51.7,
4-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(4-
nitrophenyl)methyl)-2H-chromen-2-one (3h). A light
3
1
1
10.7, 116.7, 124.4, 125.0, 125.7, 141.5, 147.0, 147.4,
48.2, 159.3, 159.6, 160.9, 164.9 ppm. HRMS: [M] = m/
z 497.3352; Anal. Calcd for C H BrO S; C, 55.55; H,
1
yellow solid; H NMR (CDCl 400 MHz): δ 6.10 (s, 1H,
3
CH), 7.24–8.09 (m, 12H, Ar-H), 8.16 (s, 1H, OH), 8.18 (s,
2
3
13
6
13
2.63; found: C, 55.53; H, 2.62%.
1H, OH) ppm. C NMR (CDCl 100 MHz): δ 48.3,
3
3
-((4-Fluoro-2-chlorophenyl)(4-hydroxy-2-oxo-2H-
116.2, 116.7, 116.8, 123.8, 124.4, 125.1, 125.2, 127.5,
133.3, 143.3, 146.9, 164.8, 169.1 ppm. HRMS:
[M + H] = m/z 458.0342; Anal. Calcd for C H NO : C,
chromen-3-yl)methyl)-4-hydroxy-2H-chromen-2-one (3c).
A white solid; H NMR (CDCl 400 MHz): δ 6.02 (s,
1
3
25 15
8
1
H, CH) 6.82–7.64 (m, 11H, Ar-H), 7.99 (s, 1H, OH),
65.65; H, 3.31; N, 3.06; found: C, 65.60; H, 3.30; N, 3.29%.
1
3
8.05 (s, 1H, OH) ppm. C NMR (CDCl 100 MHz):
4-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(4-
3
δ 55.2, 114.0, 116.6, 124.3, 124.8, 126.7, 127.6, 132.7,
46.9, 147.6, 152.2, 158.4, 163.9, 164.2 ppm. HRMS:
M + H] = m/z 464.1414; Anal. Calcd for C H ClFO :
methoxyphenyl)methyl)-2H-chromen-2-one (3i).
solid; H NMR (CDCl3 400 MHz): δ 3.78 (s, 3H,
A white
1
1
[
OCH ), 6.03 (s, 1H, CH), 6.82–7.63 (m, 12H, Ar-H),
2
5
14
6
3
13
C, 64.60; H, 3.04; found: C, 64.59; H, 3.03%.
7.99 (s, 1H, OH), 8.04 (s, 1H, OH) ppm. C NMR
3
-((4-Ethoxyphenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)
(CDCl 100 MHz): δ 35.5, 55.2, 114.0, 116.6, 124.3,
3
methyl)-4-hydroxy-2H-chromen-2-one (3d). A white solid;
124.8, 126.9, 127.6, 132.7, 146.9, 147.6, 152.2, 158.4,
163.9, 164.2 ppm. HRMS: [M + H] = m/z 443.1645;
Anal. Calcd for C H O : C, 70.58; H, 4.10; found: C,
1
H NMR (CDCl 400 MHz): δ 1.37 (t, 3H, CH ) 3.98 (q,
3
3
2
8
H, CH ), 6.03 (s, 1H, CH), 6.82–7.63 (m, 12H, Ar-H),
.00 (s, 1H, OH), 8.04 (s, 1H, OH) ppm. C NMR
2
26 18 7
1
3
70.55; H, 4.07%.
(CDCl3 100 MHz): δ 19.0, 38.0, 63.4, 114.5, 116.6,
3-((4-Chlorophenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)
1
1
4
24.3, 124.8, 126.7, 127.5, 132.7, 139.9, 140.2, 140.5,
57.8, 163.9, 164.1 ppm. HRMS: [M + H] = m/z
57.0342; Anal. Calcd for C H O : C, 71.05; H, 4.42;
methyl)-4-hydroxy-2H-chromen-2-one (3j). A white solid;
1
H NMR (CDCl 400 MHz): δ 6.09 (s, 1H, CH), 7.20–
3
7.64 (m, 12H, Ar-H), 7.98 (s, 1H, OH), 8.05 (s, 1H, OH)
2
7 20 7
13
found: C, 71.03; H, 4.40%.
ppm. C NMR (CDCl 100 MHz): δ 55.2, 114.0, 116.6,
3
4
-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(2,3-
124.3, 124.8, 126.9, 127.6, 132.7, 147.0, 147.6, 152.2,
158.4, 163.9, 164.2 ppm. HRMS: [M] = m/z 460.0814.
Anal. Calcd for C H ClO C, 67.20; H, 3.38; found: C,
dimethoxyphenyl)methyl)-2H-chromen-2-one (3e). A white
solid; H NMR (CDCl 400 MHz): δ 3.72 (s, 3H, OCH ),
1
3
3
25 15
6:
3
.85 (s, 3H, OCH ), 6.17 (s, 1H, CH), 6.86–7.61 (m, 11H,
67.17; H, 3.87%.
3
13
Ar -H), 8.00 (s, 1H, OH), 8.01 (s, 1H, OH) ppm.
C
3
-((4-Bromophenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)
NMR (CDCl 100 MHz): δ 33.4, 55.7, 59.9, 110.0, 110.2,
methyl)-4-hydroxy-2H-chromen-2-one (3k). A white solid;
3
1
110.3, 110.7, 111.0, 111.7, 116.5, 116.8, 120.1, 123.5,
H NMR (CDCl 400 MHz): δ 6.10 (s, 1H, CH), 7.24–8.09
3
1
1
24.3, 124.7, 129.3, 132.4, 139.3, 139.3, 143.2, 143.4,
44.2, 147.2, 152.1, 159.1, 160.9, 163.8 ppm. HRMS:
(m, 12H, Ar-H), 8.16 (s, 1H, OH), 8.18 (s, 1H, OH) ppm.
13
C NMR (CDCl 100 MHz): δ 55.2, 114.0, 116.6, 124.3,
3
[
M + H] = m/z 473.1945; Anal. Calcd for C H O : C,
124.8, 126.9, 127.6, 132.7, 147.0, 147.6, 152.2, 158.4,
2
7 20 8
68.64; H, 4.27; found: C, 68.60; H, 4.24%.
163.9, 164.2 ppm. HRMS: [M] = m/z 504.0209. Anal.
4
-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)(3,4-
Calcd for C25
H15BrO : C, 61.12; H, 3.08; found: C,
6
dimethoxyphenyl)methyl)-2H-chromen-2-one (3f). A white
61.10; H, 3.06%.
1
solid; H NMR (CDCl 400 MHz): δ 3.72 (s, 3H, OCH ),
3
3
3-((4-Fluorophenyl)(4-hydroxy-2-oxo-2H-chromen-3-yl)
3
.85 (s, 3H, OCH ), 6.06 (s, 1H, CH) 6.70–7.63 (m, 11H,
methyl)-4-hydroxy-2H-chromen-2-one (3l). A white solid;
H NMR (CDCl3 400 MHz): δ 6.02 (s, 1H, CH),
3
1
3
1
Ar-H), 8.00 (s, 1H, OH), 8.05 (s, 1H, OH) ppm. C NMR
(
1
CDCl 100 MHz): δ 35.2, 55.7, 56.0, 110.3, 111.2, 116.6,
18.9, 124.3, 124.8, 127.5, 132.8, 139.2, 139.5, 139.7,
6.82–7.64 (m, 12H, Ar-H), 7.99 (s, 1H, OH), 8.04 (s, 1H,
3
13
OH) ppm. C NMR (CDCl 100 MHz): δ 36.1, 105.7,
3
148.0, 149.1, 161.8, 162.1 ppm. HRMS: [M + H] = m/z
116.4, 116.6, 124.4, 124.8, 126.4, 126.8, 128.6, 128.9,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. N. Nadaf and K. Shivashankar
Vol 000
1
5
32.8, 135.1, 145.1, 162.9 ppm. HRMS: [M] = m/z
[9] Kasibabu, B. S. B.; Bhamore, J. R.; D’souza, S. L.; Kailasa, S.
K. RSC Adv 2015, 5, 39182.
10] Ammar, H.; Fery-Forgues, S.; Gharbi, R. E. Dyes Pigm 2003,
7, 259.
21.3130; Anal. Calcd for C H FO : C, 69.77; H, 3.51;
2
5
15
6
[
found: C, 69.75; H, 3.50%.
5
[
[
11] Murray, R. D. H. Fortchemie 1991, 35, 67.
12] Kiyani, H.; Darbandi, H. Chiang Mai J Sci 2017, 44, 1002.
3
-((3-Bromo-4-methoxyphenyl)(4-hydroxy-2-oxo-2H-
chromen-3-yl)methyl)-4-hydroxy-2H-chromen-2-one (3m).
A white solid; H NMR (CDCl 400 MHz): δ 3.87 (s, 3H,
OCH ), 6.02 (s, 1H, CH) 6.82–7.64 (m, 11H, Ar-H), 7.99
s, 1H, OH), 8.05 (s, 1H, OH) ppm. C NMR (CDCl3
00 MHz): δ 36.1, 53.8, 105.6, 116.4, 116.6, 124.4,
24.8, 126.4, 126.8, 128.6, 128.9, 132.8, 135.1, 145.1,
62.8 ppm. HRMS: [M] = m/z 521.3130; Anal. Calcd for
1
[13] Tasior, M.; Poronik, Y. M.; Vakuliuk, O.; Sadowski, B.;
3
Karczewski, M.; Gryko, D. T. J Org Chem 2014, 18, 8723.
3
[14] Kolita, S.; Borah, P.; Naidu, P. S.; Bhuyan, P. J. Tetrahedron
1
3
2
016, 72, 532.
15] Sangshetti, J. N.; Kokare, N. D.; Shinde, D. B. Green Chem
Lett Rev 2009, 2, 233.
16] Montagut-Romans, A.; Boulven, M.; Lemaire, M.; Popowycz,
F. New J Chem 2014, 38, 1794.
17] Jagadishbabu, N.; Shivashankar, K. J Heterocyclic Chem
017, 54, 1543.
18] Mayank; Singh, A.; Raj, P.; Kaur, R.; Singh, A.; Kaurd, N.;
Singh, N. New J Chem 2017, 41, 3872.
19] Kidwai, M.; Bansal, V.; Mothsra, P.; Saxena, S.; Somvanshi,
R. K.; Dey, S.; Singh, T. P. J Mol Catal A: Chem 2007, 268, 76.
(
[
1
1
1
[
[
C H BrO C, 59.90; H, 3.29; found: C, 59.87; H,
2
6
17
7:
2
3
.28%.
[
4
-Hydroxy-3-((4-hydroxy-2-oxo-2H-chromen-3-yl)
[
(
naphthalen-2-yl)methyl)-2H-chromen-2-one (3n). A white
solid; H NMR (CDCl 400 MHz): δ 6.24 (s, 1H, CH),
.24–8.00 (m, 15H, Ar-H), 8.02 (s, 1H, OH) 8.08 (s, 1H,
OH) ppm. C NMR (CDCl 100 MHz): δ 36.4, 116.6,
24.4, 124.6, 124.9, 125.2, 125.8, 126.2, 127.5, 127.8,
28.4, 132.3, 132.6, 132.8, 133.3, 152.1, 152.9, 156.2,
60.9, 163.8 ppm. HRMS: [M + H] = m/z 463.6214;
Anal. Calcd for C H O : C, 75.32; H, 3.92; found: C,
5.30; H, 3.89%.
1
3
[
[
20] Siddiqui, Z. N.; Farooq, F. Cat Sci Technol 2011, 1, 810.
21] Zhu, A.; Wang, M.; Lingjun, L.; Wang, J. RSC Adv 2015, 5,
7
13
73974.
3
[
22] Singh, P.; Kumar, P.; Katyal, A.; Kalra, R.; Dass, S. K.;
1
1
1
Prakash, S.; Chandra, R. Catal Lett 2010, 134, 303.
[
23] Karimian, R.; Piri, F.; Safari, A. A.; Davarpanah, S. J. J Nano
Chem 2013, 3, 52.
[
24] Rezaei, R.; Moezzi, F.; Doroodmand, M. M. Chin Chem Lett
2
9 18 6
2
2
014, 25, 183.
7
[
25] Zhu, A.; Bai, S.; Lingjun, L.; Wang, M.; Wang, J. Catal Lett
015, 145, 1089.
[
[
26] Boroujeni, K. P.; Ghasemi, P. Cat Com 2013, 37, 50.
27] Tabatabaeian, K.; Heidari, H.; Khorshidi, A.; Mamaghani, M.;
CONFLICTS OF INTEREST
Mahmoodi, N. O. J Serb Chem Soc 2012, 77, 407.
28] Karmakar, B.; Nayak, A.; Banerji, J. Tetrahedron Lett 2012,
53, 4343.
[
There are no conflicts of interest to declare.
[
29] Qi, X.; Xue, M. W.; Sun, X. J.; Zhi, Y.; Zhou, J. F. Res Chem
Intermed 2014, 40, 1187.
[
30] Mehrabi, H.; Abusaidi, H. J Iran Chem Soc 2010, 7, 890.
Acknowledgments. We would like to acknowledge the financial
support of Department of Science and Technology-Science and
Engineering Research Board (DST-SERB) New Delhi, India, un-
der the Fast Track Young Scientist Scheme (Grant No. SB/FT/CS-
[31] Tabatabaeian, K.; Zanjanchi, M. A.; Mamaghani, M.; Dadashi,
A. J Adv Chem 2015, 11, 3532.
[32] Zeydi, M. M.; Mahmoodi, N. Int J Nano Dimens 2016, 7, 174.
[33] Niknam, K.; Sajadi, S. A.; Hosseini, R.; Baghernejad, M. Iran
J Catal 2014, 4, 163.
0
28/2013 dated: 09.06.2014, 24.09.2015, and 12.09.2016) in the
[34] Shirini, F.; Abedini, M.; Zamani, S.; Moafi, H. F. J Nanostruct
form of major research project.
Chem 2015, 5, 123.
[
[
35] Shamala, D.; Shivashankar, K. Synth Commun 2017, 47, 105.
36] Beerappa, M.; Shivashankar, K. J Heterocyclic Chem 2017,
REFERENCES AND NOTES
54, 2197.
[37] Beerappa, M.; Shivashankar, K. Synth Commun 2018, 48,
[
1] Sagar, A.; Babu, V. N.; Dey, A.; Sharada, D. S. Tetrahedron
Lett 2015, 56, 2710.
2] Karimi-Jaberi, Z.; Nazarifar, M. R.; Pooladian, B. Chin Chem
Lett 2012, 23, 781.
146.
[38] Sagadevan, A.; Lyu, P. C.; Hwang, K. C. Green Chem 2016,
[
18, 4526.
[39] Xuan, J.; Xia, X. D.; Zeng, T. T.; Feng, Z. J.; Chen, J. R. O.;
[
3] Manolov, L.; Caecilina, M. M.; Danchev, N. Eur J Med Chem
Lu, L. Q.; Xiao, W. J. Angew Chem Int Ed 2014, 53, 5653.
[40] Yin, X.; Li, L.; Jiang, W.; Zhang, Y.; Zhang, X.; Wan, L.; Hu,
J. ACS Appl Mater Interfaces 2016, 8, 15258.
[41] Masuda, Y.; Ishida, N.; Murakami, M. J Am Chem Soc 2015,
137, 14063.
2
006, 14, 882.
[4] Zhou, H.; Dong, F.; Du, X.; Zhou, Z.; Huo, H.; Wang, W.;
Zhan, H.; Dai, Y.; Meng, J.; Sui, Y.; Li, J.; Sui, F.; Zhai, Y. Bioorg Med
Chem Lett 2016, 26, 3876.
[
5] Sashidhara, K. V.; Kumar, M.; Modukuri, R. K.; Sonkar, R.;
[42] Liu, X.; Cong, T.; Liu, P.; Sun, P. J Org Chem 2016, 81, 7256.
[43] Yasu, Y.; Koike, T.; Akita, M. Chem Commun 2013, 49,
2037.
[44] Leng, J.; Wang, S. M.; Qin, H. L. Beilstein J Org Chem 2017,
13, 903.
Bhatia, G.; Khanna, A. K.; Rai, S.; Shukla, R. Bioorg Med Chem Lett
011, 21, 4480.
2
2
[6] Musa, M. A.; Cooperwood, J. S.; Khan, M. F. Curr Med Chem
008, 15, 2664.
[
7] Choudhary, M. I.; Fatima, N.; Khan, K. M.; Jalil, S.; Iqbal, S.
Atta-ur-Rahman Bioorg Chem 2006, 14, 8066.
8] Sonmez, F.; Kurt, B. Z.; Gazioglu, I.; Basile, L.; Dag, A.;
[45] Yang, D.; Huang, B.; Wei, W.; Li, J.; Lin, G.; Liu, Y.; Ding, J.;
Sun, P.; Wang, H. Green Chem 2016, 18, 5630.
[46] Chen, Y. Z.; Wang, D. H.; Chen, B.; Zhong, J. J.; Tung, C. H.;
Wu, L. Z. J Org Chem 2012, 77, 6773.
[
Cappello, V.; Ginex, T.; Kucukislamoglu, M.; Guccione, S. J Enzyme
Inhib Med Chem 2017, 32, 285.
[47] Cheng, Y.; Yang, J.; Qu, Y.; Li, P. Org Lett 2012, 14, 98.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Visible Light-Induced Synthesis of Biscoumarin Analogs under Catalyst-Free
Conditions
[48] Helmy, S.; Leibfarth, F. A.; Oh, S.; Poelma, J. E.; Hawker, C.
[52] Tiwari, J.; Saquib, M.; Singh, S.; Tufail, F.; Singh, M.; Singh,
J.; Alaniz, J. R. D. J Am Chem Soc 2014, 136, 8169.
J.; Singh, J. Green Chem 2016, 18, 3221.
[
49] Laurier, E. K. G. M.; Vermoortele, F.; Ameloot, R.; Vos, D. E.
D.; Hofkens, J.; Roeffaers, M. B. J. J Am Chem Soc 2013, 135, 14488.
50] Liu, G.; Niu, P.; Yin, L.; Cheng, H. M. J Am Chem Soc 2012,
34, 9070.
51] Hoffmann, N. Chem Rev 2008, 108, 1052.
[53] Davoodinia, A.; Moghaddas, M. Der Pharma Chemica 2015,
7, 46.
[54] Hari, D. P.; Konig, B. Org Lett 2011, 13, 3852.
[55] Zhang, M.; Fu, q.; Gao, G.; He, H.; Zhang, Y.; Wu, Y.; Zhang,
Z. ACS Sustainable Chem Eng 2017, 5, 6175.
[
1
[
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet