Soluble Glass, an Efficient Promoter for the Cascade Addition-Cyclization Reaction of 4-Hydroxycoumarins to Chalcone Derivatives

Full text of DOI:10.1080/00304948.2020.1833694

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
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Soluble Glass, an Efficient Promoter for the
Cascade Addition-Cyclization Reaction of 4-
Hydroxycoumarins to Chalcone Derivatives
Mojtaba Lashkari , Majid Ghashang & Ali Abedi-Madiseh
To cite this article: Mojtaba Lashkari , Majid Ghashang & Ali Abedi-Madiseh (2021) Soluble
Glass, an Efficient Promoter for the Cascade Addition-Cyclization Reaction of 4-Hydroxycoumarins
to Chalcone Derivatives, Organic Preparations and Procedures International, 53:1, 52-58, DOI:
10.1080/00304948.2020.1833694
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ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
2021, VOL. 53, NO. 1, 52–58
https://doi.org/10.1080/00304948.2020.1833694
EXPERIMENTAL PAPER
Soluble Glass, an Efficient Promoter for the Cascade
Addition-Cyclization Reaction of 4-Hydroxycoumarins
to Chalcone Derivatives
Mojtaba Lashkaria, Majid Ghashangb, and Ali Abedi-Madisehb
b
aFaculty of Science, Velayat University, Iranshahr, Iran; Department of Chemistry, Najafabad Branch,
Islamic Azad University, Najafabad, Iran
ARTICLE HISTORY Received 4 February 2020; Accepted 18 July 2020
The combination of two or more pharmacophoric subunits is an important and efficient
strategy in organic synthesis for the construction and architecture of more effective drugs.
With the use of this strategy, the original characteristics of the parent molecules remain,
but the progeny molecules may also show entirely new medicinal aspects. Pyrano[3,2-
c]chromen-5-one skeletons are good examples: they were designed by combining a
coumarin moiety and an a,b-unsaturated carbonyl structure. Various a,b-unsaturated
carbonyl compounds are used as anti-cancer, anti-inflammatory, anti-tuberculosis, and
anti-fungal materials.1–2 On the other hand, naturally extracted compounds such as the
coumarins are accessible scaffolds for constructing anticancer, antimicrobial, antiviral,
antioxidant, and anti-inflammatory drugs.3–7
Among the methods that have been used for the synthesis of pyrano[3,2-c]chromene
derivatives, the combination of 4-hydroxycoumarin and a,b-unsaturated carbonyl com-
pounds is of great interest due to the simplicity and efficiency of the method and this
was reported by Moreau and coworkers using a Brønsted acidic catalyst.8 Subsequently,
AuCl3/Ag(OTf)3,9 SiO2-ZnCl2,10 I2/H2SO4,11 Cu(OTf)2,12 Al(OTf)3,13 DDQ,14 molecular
iodine,15 ZnCl2,16 and alkaline earth metal17 catalytic systems have been developed for
this transformation. This becomes all the more important in the light of the fact that
compounds comprised of pyran and coumarin structural units are known for anti-
cancer, anti-HIV, anti-inflammatory, and anti-hepatitis activities. Thus, significant
efforts have been expended to make combinations of these nuclei.18–29 Recognizing the
drug potential of pyrano[3,2-c]chromene core structures has encouraged us to provide a
new method for the reaction of 4-hydroxycoumarins and a,b-unsaturated car-
bonyl compounds.
In this, soluble glass is used to promote the production of 2,4-diaryl-4H,5H-pyr-
ano[3,2-c]chromen-5-one derivatives in aqueous media (Scheme 1).
We evaluated the feasibility of the synthesis of 1,3-diphenylpyrano[2,3-c]chromen-5(1H)-
one using soluble glass under different conditions. To begin this, 4-hydroxycoumarin
(1 mmol) and chalcone (1 mmol) were combined with soluble glass in several solvents
(CH2Cl2, hexane, EtOAc, EtOH and water) under reflux conditions for 3h. None of the
desired product was detected in CH2Cl2 and hexane. The product was obtained in EtOAc
CONTACT Mojtaba Lashkari
mojtaba_chem_84@yahoo.com
Faculty of Science, Velayat University, Iranshahr, Iran
ß 2020 Taylor & Francis Group, LLC

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
53
R5
R4
R3
R2
O
O
R2
OH
O
R1
R3
R4
R1
Soluble glass
Water, Reflux
+
O
O
O
1
3a-v
R5
2
Scheme 1. Synthesis of pyrano[3,2-c]coumarin derivatives.
Table 1. Synthesis of pyrano[3,2-c]coumarin derivatives (3a-z) using liquid glass as a catalyst.
Entry
R1
R2
R3
R4
R5
Product
Time (h)
Yield (%)a
m.p. (ꢀC) [Lit. m.p.]Ref.
1
2
3
4
5
6
7
8
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
3p
3q
3r
3
4
6
87
85
83
79
88
80
77
89
86
96
78
88
88
94
90
88
92
89
82
86
87
80
172-174 [173-175]11
193-195 [192-194]13
183-185 [184-186]13
133-135 [132-138]13
196-198 [196-197]11
201-203
H
CH3
H
H
H
Cl
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
CH3
H
OCH3
Cl
4.5
2.5
2.5
3
2.5
2.5
3
3.5
3
3
3
3
2.5
2.5
4
Cl
H
H
H
H
189-191
NO2
H
227-229 [-]12
9
NO2
Br
232-234 [230-231]9
212-214 [210-211]11
155-157 [156-158]9
226-228 [225-227]9
209-211
10
11
12
13
14
15
16
17
18
19
20
21
22
H
H
H
H
H
H
H
H
H
CH3
CH3
C(CH3)3
Cl
H
OCH3
Cl
H
H
Cl
H
H
Br
H
H
221-223 [-]12
CH3
Cl
H
H
213-215 [212-213]14
233-235 [231-232]9
243-245 [239-241]9
208-210 [210-211]9
146-148 [144-146]11
203-205 [202-203]9
220-222 [218-219]9
205-207 [206-207]9
H
Cl
CH3
CH3
H
H
H
OCH3
H
H
H
3s
3t
3u
3v
4
3
5
4
CH3
OCH3
H
H
OCH3
H
aIsolated yields.
and EtOH in low yields (EtOAc (20%), EtOH (40%)). Interestingly, the product was pre-
pared in an aqueous environment with high yields (87%). In solvent-free media, a complex
mixture was formed, and only 15% of product was obtained following workup.
Next, a series of chalcone derivatives were subjected to this approach and the results
are summarized in Table 1. In each case, the desired product was produced in good to
excellent yields. We observed that, when the donor groups are substituted, the rate of
the reaction is slowed.
In continuation of our research,30 we examined cognate preparations of 5-amino-7-aryl-
7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitrile derivatives (Scheme 2, Table 2,
products 7a-7j). All reactions were completed in short reaction times with high yields. A ser-
ies of aldehyde derivatives containing different substitutions were subjected to the reaction.
In all of these reactions the catalyst had satisfactory performance and high efficiency.
In summary, we have demonstrated a cascade addition-cyclization reaction of 4-
hydroxycoumarins with chalcone derivatives for the synthesis of functionalized 2,4-

54
M. LASHKARI ET AL.
NH2
CN
Ar
liquid glass
NH
N
N
ArCHO
+
+ CH2(CN)2
N
N
N
NH2
Water, Reflux
N
H
6
5
4
7a-j
Scheme 2. Synthesis of 5-amino-7-aryl-7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitrile deriva-
tives (7a-j).
Table 2. Synthesis of 5-amino-7-aryl-7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitrile deriva-
tives using liquid glass as a catalyst.
Entry
Ar
Product
Time (min)
Yield (%)a
m.p. (ꢀC) [Lit. m.p.]Ref.
1
2
3
4
5
6
7
8
9
10
Ph
4-ClC6H4
2-ClC6H4
4-MeC6H4
4-MeOC6H4
4-BrC6H4
3,4-diMeOC6H3
4-NO2C6H4
2,4-diClC6H3
3-ClC6H4
7a
7b
7c
7d
7e
7f
7g
7h
7i
50
45
50
70
70
45
80
45
50
45
85
90
86
79
85
94
81
89
86
90
235-237
259-261 [257-258]31
262-264 [263-266]31
247-249 [245-246]31
222-224 [218-219]31
267-269 [264-266]31
239-241 [235-237]31
245-247 [245-247]31
276-278 [274-277]31
251-253
7j
aIsolated yield.
diaryl-4H,5H-pyrano[3,2-c]chromen-5-ones using soluble glass as a promoter in aque-
ous media. This methodology offers a straightforward and rapid access to the pyr-
ano[3,2-c]chromen-5-one structures. We hope that our results will stimulate further
investigations of these useful compounds in drug design and discovery.
Experimental section
All reagents were purchased from Merck and used without further purification. The NMR
spectra were recorded on a Bruker Avance DPX 400 MHz instrument in DMSO-d6 as a
solvent. Melting points were determined in open capillaries with a BUCHI 510 melting
point apparatus and are uncorrected. TLC was performed on silica gel Polygram SIL G/
UV 254 plates. Elemental analysis was performed on a Heraeus CHN-O-Rapid analyzer.
Synthesis of pyrano[3,2-c]coumarin derivatives (3a-v); General procedure
A mixture of 4-hydroxycoumarin (1.0 mmol), chalcone (1.0 mmol), and five drops of
soluble glass (10% w/v) was refluxed in water for the appropriate time (Scheme 1). The
progress of the reaction was monitored by TLC (silica gel, eluent: ethyl acetate/hexane
1/4). After completion of the reaction, the reaction mixture was cooled to room tem-
perature and filtered. The solid was purified by recrystallization from EtOH. Known
compounds were identified by matching their melting points with those of the literature
cited in the tables and/or were fully characterized. All novel compounds were fully
characterized.

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
55
2,4-Diphenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3a)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.68 (d, J ¼ 5.1 Hz, 1H, CH-sp3), 5.85 (d,
J ¼ 5.3 Hz, 1H), 7.24 (t, J ¼ 7.7 Hz, 1H), 7.28–7.47 (m, 9H), 7.57 (t, J ¼ 7.8 Hz, 1H), 7.75
(d, J ¼ 7.8 Hz, 2H), 8.02 (d, J ¼ 7.8 Hz, 1H) ppm; 13C-NMR (100 MHz, DMSO-d6): d ¼
36.8, 103.9, 104.4, 115.3, 116.9, 123.1, 124.2, 125.2, 127.4, 128.6, 128.9, 129.1, 129.5,
131.6, 132.3, 143.2, 147.3, 152.7, 156.1, 161.3 ppm.
Anal. Calcd for C24H16O3: C, 81.80; H, 4.58. Found: C, 81.73; H, 4.48.
2-Phenyl-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromen-5-one (3b)
1H NMR (400 MHz, DMSO-d6): d ¼ 2.32 (s, 3H, CH3), 4.70 (d, J ¼ 4.9 Hz, 1H), 5.82 (d,
J ¼ 5.0 Hz, 1H), 7.11 (d, J ¼ 8.0 Hz, 2H), 7.26-7.47 (m, 7H), 7.55 (d, J ¼ 8.0 Hz, 1H), 7.71
(d, J ¼ 7.8 Hz, 2H), 8.02 (d, J ¼ 7.8 Hz, 1H) ppm.
Anal. Calcd for C25H18O3: C, 81.95; H, 4.95. Found: C, 81.90; H, 4.88.
4-(4-Methoxy-phenyl)-2-phenyl-4H-pyrano[3,2-c]chromen-5-one (3d)
1H NMR (400 MHz, DMSO-d6): d ¼ 3.76 (s, 3H, OCH3), 4.69 (d, J ¼ 5.1Hz, 1H), 5.81
(d, J ¼ 5.3 Hz, 1H), 6.89 (d, J ¼ 8.0 Hz, 2H), 7.28-7.47 (m, 7H), 7.62 (t, J ¼ 7.8 Hz, 1H),
7.71 (d, J ¼ 7.8Hz, 2H), 8.04 (d, J ¼ 7.9 Hz, 1H) ppm.
Anal. Calcd for C25H18O4: C, 78.45; H, 4.70. Found: C, 78.38; H, 4.61.
4-(4-Chlorophenyl)-2-phenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3e)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.73 (d, J ¼ 5.1 Hz, 1H, CH-sp3), 5.87 (d,
J ¼ 5.3 Hz, 1H), 7.24 (t, J ¼ 7.6 Hz, 1H), 7.29–7.48 (m, 9H), 7.59 (t, J ¼ 7.7 Hz, 1H), 7.75
(d, J ¼ 7.6 Hz, 2H), 8.02 (d, J ¼ 8.0 Hz, 1H) ppm; 13C-NMR (100 MHz, DMSO-d6): d ¼
36.9, 104.6, 110.4, 115.3, 116.4, 123.2, 123.6, 126.2, 128.5, 128.9, 129.0, 129.7, 129.9,
131.3, 136.7, 141.3, 147.8, 152.7, 156.3, 161.3 ppm.
Anal. Calcd for C24H15ClO3: C, 74.52; H, 3.91. Found: C, 74.44; H, 3.83.
4-(3-Chlorophenyl)-2-phenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3f)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.70 (d, J ¼ 5.4 Hz, 1H, CH-sp3), 5.87 (d,
J ¼ 5.3 Hz, 1H), 7.18-7.46 (m, 9H), 7.58 (t, J ¼ 8.0 Hz, 1H), 7.74 (d, J ¼ 7.8 Hz, 2H), 8.03
(d, J ¼ 8.0 Hz, 1H) ppm; 13C-NMR (100 MHz, DMSO-d6): d ¼ 36.7, 104.7, 110.3, 115.4,
116.4, 123.2, 123.7, 126.2, 127.8, 128.0, 128.7, 129.0, 129.1, 129.6, 129.9, 130.8, 131.3,
141.4, 148.2, 152.7, 156.5, 161.4 ppm.
Anal. Calcd for C24H15ClO3: C, 74.52; H, 3.91. Found: C, 74.48; H, 3.86.
4-(2-Chlorophenyl)-2-phenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3g)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.71 (d, J ¼ 5.3 Hz, 1H, CH-sp3), 5.86 (d,
J ¼ 5.2 Hz, 1H), 7.29-7.47 (m, 9H), 7.57 (t, J ¼ 7.9 Hz, 1H), 7.73 (d, J ¼ 7.8 Hz, 2H), 8.00
(d, J ¼ 8.0 Hz, 1H) ppm; 13C-NMR (100 MHz, DMSO-d6): d ¼ 36.5, 104.6, 110.3, 115.5,

56
M. LASHKARI ET AL.
116.5, 123.2, 123.6, 126.3, 128.3, 128.7, 129.1, 129.4, 129.8, 130.3, 130.6, 131.3, 132.9,
148.2, 152.6, 156.6, 161.3 ppm.
Anal. Calcd for C24H15ClO3: C, 74.52; H, 3.91. Found: C, 74.45; H, 3.88.
4-(3-Nitro-phenyl)-2-phenyl-4H-pyrano[3,2-c]chromen-5-one (3h)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.89 (d, J ¼ 4.9 Hz, 1H, CH-sp3), 5.84 (d,
J ¼ 5.1 Hz, 1H), 7.37–7.55 (m, 6H), 7.64 (t, J ¼ 7.6 Hz, 1H), 7.78 (d, J ¼ 7.8 Hz, 2H), 7.83
(d, J ¼ 7.8 Hz, 1H), 8.04 (d, J ¼ 7.9 Hz, 1H), 8.12 (d, J ¼ 7.9 Hz, 1H), 8.26 (d, J ¼ 7.9 Hz,
1H) ppm.
Anal. Calcd for C24H15NO5: C, 72.54; H, 3.80; N, 3.52. Found: C, 72.48; H, 3.76;
N, 3.45.
4-(4-Bromophenyl)-2-phenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3j)
1H-NMR (400 MHz, DMSO-d6): d ¼ 4.71 (d, J ¼ 4.8 Hz, 1H, CH-sp3), 5.80 (d,
J ¼ 4.9 Hz, 1H), 7.25-7.49 (m, 9H), 7.62 (t, J ¼ 7.8 Hz, 1H), 7.72 (d, J ¼ 7.8 Hz, 2H), 8.02
(d, J ¼ 7.9 Hz, 1H) ppm.
Anal. Calcd for C24H15BrO3: C, 66.84; H, 3.51. Found: C, 66.75; H, 3.46.
4-(4-(tert-Butyl)phenyl)-2-phenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3m)
1H-NMR (400 MHz, DMSO-d6): d ¼ 1.27 (s, 9H), 4.69 (d, J ¼ 5.1 Hz, 1H, CH-sp3), 5.85
(d, J ¼ 5.0 Hz, 1H), 7.02 (d, J ¼ 7.8 Hz, 2H), 7.16 (d, J ¼ 7.8 Hz, 2H), 7.29-7.46 (m, 5H),
7.55 (t, J ¼ 7.8 Hz, 1H), 7.72 (d, J ¼ 7.8 Hz, 2H), 8.02 (d, J ¼ 7.9 Hz, 1H) ppm; 13C-NMR
(100 MHz, DMSO-d6): d ¼ 31.3, 34.4, 36.4, 104.2, 110.4, 115.5, 116.5, 123.2, 123.7, 125.6,
125.9, 126.3, 126.9, 128.8, 129.1, 129.7, 131.3, 141.4, 152.3, 153.4, 156.7, 159.7, 161.4 ppm.
Anal. Calcd for C28H24O3: C, 82.33; H, 5.92. Found: C, 82.27; H, 5.89.
2-(4-Chloro-phenyl)-4-(4-methoxy-phenyl)-4H-pyrano[3,2-c]chromen-5-one (3n)
1H-NMR (400 MHz, DMSO-d6): d ¼ 3.78 (s, 3H, OCH3), 4.69 (d, J ¼ 5.0 Hz, 1H, CH-
sp3), 5.84 (d, J ¼ 5.2 Hz, 1H), 6.89 (d, J ¼ 8.0 Hz, 2H), 7.31–7.46 (m, 6H), 7.63 (t,
J ¼ 7.6 Hz, 1H), 7.69 (d, J ¼ 7.9 Hz, 2H), 8.03 (d, J ¼ 7.9 Hz, 1H) ppm.
Anal. Calcd for C25H17ClO4: C, 72.03; H, 4.11. Found: C, 71.94; H, 4.03.
9-Methyl-2,4-diphenyl-4H,5H-pyrano[3,2-c]chromen-5-one (3o)
1H-NMR (400 MHz, DMSO-d6): d ¼ 2.44 (s, 3H, CH3), 4.71 (d, J ¼ 4.8 Hz, 1H, CH-
sp3), 5.80 (d, J ¼ 4.9 Hz, 1H), 7.25-7.49 (m, 9H), 7.62 (t, J ¼ 7.8 Hz, 1H), 7.72 (d,
J ¼ 7.8 Hz, 2H), 8.02 (d, J ¼ 7.9 Hz, 1H) ppm.
Anal. Calcd for C25H18O3: C, 81.95; H, 4.95. Found: C, 81.88; H, 4.87.

ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
57
Synthesis of 5-amino-7-aryl-7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-
carbonitrile derivatives (7a-j); General procedure
A mixture of 4H-1,2,4-triazol-3-amine (1.0 mmol), malononitrile (1.0 mmol), aldehyde
(1.0 mmol) and soluble glass (30% w/v) was refluxed in water for the appropriate time
(Scheme 2). The progress of the reaction was monitored by TLC (silica gel, eluent: ethyl
acetate/hexane 1/3). After completion of the reaction, the reaction mixture was cooled
to room temperature and filtered. The solid was purified by recrystallization from
EtOH. Representative spectral data are given below.
5-Amino-7-phenyl-7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitrile (7a)
1H-NMR (400 MHz, DMSO-d6): d ¼ 5.31 (d, J ¼ 3.5 Hz, 1H, CH-sp3), 6.98 (s, 2H,
NH2), 7.23-7.32 (m, 5H), 7.72 (s, 1H), 8.84 (d, J ¼ 3.3 Hz, 1H, NH) ppm; 13C-NMR
(100 MHz, DMSO-d6): d ¼ 53.7, 56.1, 119.1, 126.1, 128.4, 129.6, 137.6, 146.9,
152.3, 154.1 ppm.
Anal. Calcd for C12H10N6: C, 60.50; H, 4.23; N, 35.27. Found: C, 60.39; H, 4.14;
N, 35.16.
5-Amino-7-(3-chlorophenyl)-7,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-
carbonitrile (7j)
1H-NMR (400 MHz, DMSO-d6): d ¼ 5.34 (d, J ¼ 3.5 Hz, 1H, CH-sp3), 7.11 (s, 2H,
NH2), 7.37-7.54 (m, 4H), 7.723 (s, 1H), 8.96 (d, J ¼ 3.3 Hz, 1H, NH) ppm; 13C-NMR
(100 MHz, DMSO-d6): d ¼ 53.8, 56.2, 119.1, 127.3, 128.3, 130.5, 132.8, 137.7, 144.6,
146.9, 152.4, 154.2 ppm.
Anal. Calcd for C12H9ClN6: C, 52.85; H, 3.33; N, 30.82. Found: C, 52.76; H, 3.25;
N, 30.74.
Acknowledgment
The authors are indebted to the Islamic Azad University, Najafabad Branch, for financial support
of this research.
ORCID
Ali Abedi-Madiseh
http://orcid.org/0000-0002-4015-4042
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