Sodium acetate/MWI: a green protocol for the synthesis of tetrahydrobenzo[α]xanthen-11-ones with biological screening

Article abstract of DOI:10.1007/s11164-019-03945-7

Abstract: An efficient, straightforward and rapid method has been developed for the synthesis of tetrahydrobenzo[α] xanthen-11-one using sodium acetate. The reaction was performed via three components: β-naphthol, dimedone with various aromatic aldehydes

Full text of DOI:10.1007/s11164-019-03945-7

Research on Chemical Intermediates
https://doi.org/10.1007/s11164-019-03945-7
Sodium acetate/MWI: a green protocol for the synthesis
of tetrahydrobenzo[α]xanthen‑11‑ones with biological
screening
Prasad Mane1 · Bipin Shinde1 · Pankaj Mundada2 · Vilas Gawade1 ·
Bhausaheb Karale4 · Arvind Burungale1,3
Received: 9 April 2019 / Accepted: 29 July 2019
© Springer Nature B.V. 2019
Abstract
An efcient, straightforward and rapid method has been developed for the synthe-
sis of tetrahydrobenzo[α] xanthen-11-one using sodium acetate. The reaction was
performed via three components: β-naphthol, dimedone with various aromatic alde-
hydes under solvent-free microwave irradiation and conventional heating condition.
We observed an efcient result for microwave synthesis than conventional heating.
The synthesized tetrahydrobenzo[α]xanthen-11-one (4a–l) was screened for their
antimicrobial activity against two bacteria (Escherichia coli and Bacillus subtilis)
and two fungal strains (Aspergillus niger and Saccharomyces cerevisiae). The syn-
thesized products: 9, 10-dihydro-9, 9-dimethyl-12-(4-nitrophenyl)-8H-benzo[a]
xanthen-11(12H)-one, 9, 10-dihydro-9, 9-dimethyl-12-(2, 4-dichlorophenyl)-8H-
benzo[a]xanthen-11(12H)-one, 9, 10-dihydro-9, 9-dimethyl-12-(6-methyl-4-oxo-
4H-chromen-3-yl)-8H-benzo[a]xanthen-11(12H)-one exhibit good antimicrobial
activity. The developed protocol is graced with appealing advantages such as high
purity, simple operation, excellent yields, inexpensive and easy availability of
catalyst.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1116
4-019-03945-7) contains supplementary material, which is available to authorized users.
*
Arvind Burungale
asburungale@gmail.com
1
2
Department of Chemistry, Yashavantrao Chavan Institute of Science, Satara,
Maharashtra 415001, India
Department of Biotechnology, Yashavantrao Chavan Institute of Science, Satara,
Maharashtra 415001, India
3
4
Department of Chemistry, S.M. Joshi College, Hadapsar, Pune, Maharashtra 411028, India
Chhatrapati Shivaji College, Satara, Maharashtra 415001, India
Vol.:(0123456789)
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P. Mane et al.
Graphic abstract
Keywords Antimicrobial screening · Microwave irradiation · Solvent-free
condition · Tetrahydrobenzo[α] xanthen-11-one
Introduction
Multicomponent reactions (MCRs) grabbed the attention of many researchers due
to easy synthesis of biologically active heterocycles [1, 2]. Multicomponent reac-
tions are the important tools in the synthesis of chemical compounds and drugs
because they have valuable advantages over conventional synthesis [3]. They show
the ideal synthesis of heterocycles with high atom efciency, simple implementa-
tion, environment benign approach and profcient conditions [4, 5]. The develop-
ment and application of sustainable multicomponent reactions (MCRs) has become
an increasingly important topic in chemistry since MCRs allow the sustainable for-
mation of products with high diversity and complexity in a combinatorial one-pot
fashion [6, 7].
Recently, the microwave-assisted organic synthesis (MAOS) is one of the suc-
cessful methodologies for organic transformations. Microwave-assisted organic syn-
thesis shows many advantages including faster, cleaner reactions, atom economy,
high product yields and operational simplicity [8–10]. Presently, the green synthesis
has become one of the most widely used approaches for the routine synthesis of
biologically active heterocyclic derivatives [11, 12]. Thus, the use of MW-assisted
synthesis in drug discovery is a large and rapidly growing research feld [13, 14].
Xanthenes and benzoxanthenes are privileged group of organic compounds
because of their extensive range of biological and pharmaceutical properties
[15–17]. Xanthene derivatives could be applied as dyes [18], cytotoxic agents
[19], anti-infammatory [20], antiviral activities [21], bactericidal [22], antagonists
to inhibit zoxalamine activity [23], in laser technology [24]. Tetrahydrobenzo[a]
xanthen-11-ones specifed wide applications in the pharmacological and industrial
1 3

Sodium acetate/MWI: a green protocol for the synthesis of…
sectors. The various methodologies were studied for their synthesis by using three-
component condensation of dimedone, aromatic aldehyde and β-naphthol. Some
methodologies for the protocol were p-toluene sulfonic acid/ionic liquid, bronsted
acidic ionic liquid, proline trifate, ceric ammonium nitrate, iodine and InCl3/P2O5
[25–39].
The vital disadvantages of reported methodologies are high-price reagents, long
reaction time, tedious work-up, large catalyst loading and hazardous reaction condi-
tions. Hence, we designed a green protocol which diminishes these disadvantages.
We developed sodium acetate/MWI as new catalytic system with high catalytic ef-
ciency, short reaction time, high product yield and easy work-up for the synthesis of
tetrahydrobenzo[α] xanthen-11-one. This is frst time report on tetrahydrobenzo[α]
xanthen-11-one green synthesis using sodium acetate/MWI catalytic system.
Experimental
General
Aldehyde, dimedone and β-naphthol were purchased from Sigma-Aldrich and used
as received; 3-formyl chromone was prepared by Vilsmeier–Haack reaction of
2-hydroxy acetophenone with DMF and POCl3. Melting points were recorded by
open-glass capillary method. The progress of reaction was monitored by thin-layer
chromatography (TLC). The IR spectrum (υmax, cm-1) was recorded on lambda
1
FTIR-7600 spectrophotometer using KBr pellets. H and 13C spectra of pure prod-
ucts were recorded by using CDCl3 solvent on Brucker 400 MHz and 100 MHz
spectrometer, respectively, with TMS as an internal standard. The proposed reaction
is conducted in Raga Scientifc Microwave.
Typical procedure for the synthesis of tetrahydrobenzo[α]xanthen‑11‑one
derivatives
A mixture of aromatic aldehyde (1 mmol), dimedone (1 mmol) and β-naphthol
(1 mmol) was microwave irradiated at 450 W with sodium acetate (15 mol%). The
TLC technique (ethyl acetate: hexane—1:9, v/v) was used to monitor the proposed
reaction. After the successful completion of reaction, reaction mixture was poured
to ice-cold water, resulting into the product. The catalyst sodium acetate becomes
soluble in water. The product obtained was recrystallized from ethanol to obtain the
pure 9, 10-dihydro-9, 9-dimethyl-12-phenyl-8H-benzo[a]xanthen-11(12H)-one.
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P. Mane et al.
Results and discussion
Optimization of reaction conditions
In quest of best reaction condition, we successfully conducted a reaction between
an aromatic aldehyde, β-naphthol and dimedone in the presence of sodium acetate
under microwave irradiation. The various number of trail reactions between 4-chlo-
robenzaldehyde (1 mmol), β-naphthol (1 mmol) and dimedone (1 mmol) were car-
ried for optimizing exact reaction condition in the absence or presence of catalyst
under microwave irradiation. The said reaction was also performed with conven-
tional heating (Table 1). The efcient results were obtained with 15 mol% sodium
acetate under microwave irradiation for tetrahydrobenzo[α]xanthen-11-one synthe-
sis (Table 2).
Initially, we have attempted conventional method by using NaOAc at 80 °C for
the synthesis of tetrahydrobenzo[α]xanthen-11-one (Scheme—1, 4a–l). The results
are summarized in Table 1. We observed long reaction time for completion of pro-
posed synthesis with low yield.
Under optimized condition, the reaction of 4-chlorobenzaldehyde, β-naphthol
and dimedone resulted into the product 9, 10-dihydro-9, 9-dimethyl-12-(4-
chlorophenyl)-8H-benzo[a]xanthen-11(12H)-one with 95% yield within 5 min. The
various substituted aromatic aldehydes (electron withdrawing, electron donating
and 3-formyl chromones) were reacted with β-naphthol and dimedone to check the
generality and efectiveness of our developed protocol. These reactions conducted
successfully, smoothly and furnished with efcient desired tetrahydrobenzo[α]xan-
then-11-one product. The proposed reaction via NaOAc/MWI catalysis is relatively
profcient with respect to yield and time of reaction than other reported catalysis
(Table 3). Sodium acetate is completely soluble in water; hence, water is used for
the complete removal of sodium acetate during work-up. This indicates there is no
leaching or degradation behavior during work-up.
Table 1 The optimization of catalyst (sodium acetate) loading for the synthesis of tetrahydrobenzo[α]
xanthen-11-one in diferent reaction mediums
Entry
Catalyst loading (mol%)
Temperature
Time (min)
Yield (%)
1
2
No catalyst
5
120
80
600
90
Trace
20
3
4
5
6
7
8
9
10
5
5
100
120
27
120
150
120
MWI
MWI
MWI
150
480
600
180
360
210
5
25
54
35
90
65
90
65
72
10
10
15
20
5
10
15
7
5
11
95
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Sodium acetate/MWI: a green protocol for the synthesis of…
Table 2 Synthesis of various tetrahydrobenzo[α]xanthen-11-ones using NaOAc as a catalyst under
microwave irradiation and solvent-free condition
Entry Aromatic aldehyde Microwave irradiation
Conventional heating Melting point (°C)
Literature
Time (min) Yield (%) Time (h) Yield (%) Found
4a
4b
5
5
92
92
3.0
90
152–153 151–153 [30]
H
O
O
O
NO2
5.0
89
177–180 178–180 [30]
H
Cl
4c
4d
5
6
95
88
5.5
6.5
91
85
180–182 180–182 [30]
204–205 204–205 [30]
H
OMe
H
O
Cl
4e
7
5
95
88
5.5
6.5
93
85
176–177 175–177 [31]
175–177 176–178 [30]
Cl
H
O
Me
4f
H
O
Br
4 g
4 h
7
8
89
88
6.5
6.5
88
86
187–188 186–188 [30]
214–215 213–215 [31]
H
O
OH
MeO
H
O
O
4i
4j
5
7
90
92
7.0
7.5
84
87
215–218 New Report
220–223 New Report
H
O
O
O
H
Me
O
O
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P. Mane et al.
Table 2 (continued)
Entry Aromatic aldehyde Microwave irradiation
Conventional heating Melting point (°C)
Time (min) Yield (%) Time (h) Yield (%) Found
Literature
O
4 k
4 l
7
8
85
88
8.0
8.0
82
84
224–226 New Report
H
Cl
Cl
O
O
O
O
Cl
239–242 New Report
H
O
4 m
4n
6
7
88
89
6.0
6.5
86
85
174–176 176–178 [40]
170–172 170–172 [40]
H
S
O
H
O
O
O
OH
Ar
O
O
NaOAc
+
+
MWI
H
Ar
O
O
1
2
3
4
Scheme 1 Multicomponent reaction between aromatic aldehyde (1 mmol), dimedone (1 mmol) and
β-naphthol (1 mmol)
Table 3 Synthesis of tetrahydrobenzo[α]xanthen-11-one in the presence of diferent catalysts
Sr. no.
Catalyst
Conditions
Time (min.)
Yield (%)
Literature
1
2
3
4
5
6
7
8
9
Sr(OTf)2
NH4Cl
CAN
InCl3
p-TSA
H3PW12O40
Graphene oxide
I2
1,2-Dichloroethane, 80 °C
Solvent free, 120 °C
Solvent free, 120 °C
Solvent free, 120 °C
Solvent free, 120 °C
Solvent free, 60 °C
Solvent free, 120 °C
Ethanol, refux
300
15
30
30
45
70
20
180
5
85
86
94
84
88
86
85
84
95
[35]
[36]
[37]
[38]
[39]
[41]
[42]
[43]
NaOAc
MWI, 450 W
Present work
A plausible mechanism of this condensation reaction is revealed in Scheme 2.
In the frst step, the olefn formation takes place by a Knoevenagel condensation
between an aromatic aldehyde and dimedone which is catalyzed by sodium acetate.
Further, Michael addition reaction of β-naphthol takes place with olefn intermediate
1 3

Sodium acetate/MWI: a green protocol for the synthesis of…
O
Ar
H
1
Ar
OH
H
O
O
O
OH
O
O
-OAc
-H2O
3
Ar
O
O
OH
HO
H
O
2
Ar
O
Ar
O
Ar
O
O
OH
OH
4
Scheme 2 A feasible mechanism for the synthesis of tetrahydrobenzo[α]xanthen-11-one
and undergoes dehydration which results into the target molecule tetrahydrobenzo[α]
xanthen-11-one.
Minimum inhibitory concentration (MIC) evaluation
The agar cub method [44] imparted the minimum inhibitory concentration (10–100 µg)
for antimicrobial testing of various tetrahydrobenzo[α]xanthen-11-one derivatives. The
two bacterial strains, E.coli (gram-negative) and B. subtilis (gram-positive bacteria)
were used for the determination of MIC values using ampicillin as positive and 1%
DMSO as negative control. Similarly, two fungal stains: A. niger and S. cereviase using
miconazole, as the standard drug was evaluated for the minimum inhibitory concentra-
tion. The above data represent the mean standard error of three replicates (Table 4).
MIC is the lowest concentration of a drug that inhibits the growth of a particular
1 3

P. Mane et al.
Table 4 Minimum inhibitory concentration (MIC) evaluation of synthesized various tetrahydrobenzo[α]
xanthen-11-one
Entry
Antibacterial activity
Antifungal activity
E. coli
B. subtilis
A. niger
S. cereviase
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
33.00 1.00
18.17 1.26
30.67 1.53
28.83 1.26
20.67 2.52
44.33 1.15
21.67 1.15
18.67 0.58
32.50 0.50
17.67 1.53
55.33 1.53
23.00 1.00
19.67 0.29
–
12.17 076
20.33 1.53
19.33 1.04
18.00 0.50
16.00 1.00
22.17 0.76
25.71 0.76
25.00 1.00
33.17 0.76
16.50 0.50
61.33 1.53
18.83 0.76
14.33 0.58
–
19.50 0.50
22.33 0.58
26.17 0.76
16.50 0.87
14.83 0.76
17.17 1.26
48.67 1.15
27.67 0.58
25.83 0.76
35.00 1.00
26.50 0.50
17.67 0.58
–
31.17 0.29
19.33 0.58
14.17 0.29
25.67 0.58
25.67 1.53
24.17 0.29
46.50 0.50
34.33 0.58
25.00 1.00
28.67 0.58
28.67 0.58
19.33 0.58
–
Ampicillin
Miconazole
16.67 0.58
20.00 1.00
organism under specifc condition. Among them, 9, 10-dihydro-9, 9-dimethyl-12-
(4-nitrophenyl)-8H-benzo[a]xanthen-11(12H)-one [4b], 9, 10-dihydro-9, 9-dime-
thyl-12-(2, 4-dichlorophenyl)-8H-benzo[a]xanthen-11(12H)-one [4e], 9, 10-dihydro-9,
9-dimethyl-12-(6-methyl-4-oxo-4H-chromen-3-yl)-8H-benzo[a]xanthen-11(12H)-one
[4j] showed best results. Tetrahydrobenzo[α]xanthen-11-ones can be anticipated to gain
synergistic efects on biological activities by the presence of nitro and chloro groups
(Entries 4b, 4e, 4j).
Spectroscopic data of some synthesized tetrahydrobenzo[α]xanthen‑11‑one
9, 10‑dihydro‑9, 9‑dimethyl‑12‑phenyl‑8H‑benzo[a]xanthen‑11(12H)‑one [4a]
1
IR (υmax, cm−1, KBr): 2956 (C-H), 1655 (C=O), 1621(C=C); HNMR (400 MHz,
CDCl3, δ ppm): 0.99 (s, 3H), 1.10 (s, 3H), 2.16 (s, 2H), 2.46 (s, 2H), 4.90 (s, 1H),
7.45–7.31 (5H, m), 7.19–7.15 (2H, m), 7.07–7.03 (1H, m), 7.73–7.82 (m, 2H), 8.17
(d, J=8.1 Hz, 1H); 13CNMR (100 MHz, CDCl3, δ ppm): 26.72, 28.42, 31.92, 34.78,
41.02, 50.23, 113.56, 116.28, 123.23, 124.17, 125.18, 126.86, 127.63, 128.08, 128.48,
134.09, 144.26, 147.36, 162.48, 196.11. Anal Calcd for C25H22O2: C, 84.72; H, 6.26%.
Found: C, 84.68; H, 6.31%. These spectroscopic values are shown in electronic supple-
mentary material (ESM 1).
1 3

Sodium acetate/MWI: a green protocol for the synthesis of…
9, 10‑dihydro‑9, 9‑dimethyl‑12‑(4‑chlorophenyl)‑8H‑benzo[a]xanthen‑11(12H)‑one
[4c]
1
IR (υmax, cm−1): 2952 (C-H), 1652 (C=O), 1621(C=C); HNMR (400 MHz,
CDCl3, δ ppm): 1.00 (s, 3H), 1.19 (s, 3H), 2.13 (s, 2H), 2.59 (s, 2H), 5.58 (s, 1H),
6.98 (d, J=8.2 Hz, 2H), 7.06 (s, 2H), 7.20 (d, J=8.1 Hz, 1H), 7.31-7.36 (m, 1H),
7.66 (d, J=8.1 Hz, 1H), 7.78 (d, J=6.3 Hz, 1H), 7.89 (d, J=8.1 Hz, 1H); 13CNMR
(100 MHz, CDCl3, δ ppm): 26.43, 27.72, 30.37, 39.08, 43.80, 51.40, 109.08,
118.98, 122.11, 122.58, 123.12, 123.38, 125.28, 126.08, 127.61, 129.42, 129.71,
131.19, 133.19, 139.61, 151.21, 162.20, 196.98. Anal Calcd for C25H21ClO2: C,
77.21; H, 5.44%. Found: C, 77.23; H, 5.49%. These spectroscopic values are shown
in electronic supplementary material (ESM 2).
9, 10‑dihydro‑9, 9‑dimethyl‑12‑(4‑nitrophenyl)‑8H‑benzo[a]xanthen‑11(12H)‑one
[4b]
IR (υmax, cm−1, KBr): 2953 (C-H), 1648 (C=O), 1622 (C=C), 1532, 1341 (NO2);
1HNMR (400 MHz, CDCl3, δ ppm): 1.10 (s, 3H), 1.21 (s, 3H), 2.03 (s, 2H), 2.51
(s, 2H), 5.43 (s, 1H), 7.10–7.32 (m, 4H), 7.58–8.08 (m, 4H), 8.25–8.30 (d, 3H);
13CNMR (100 MHz, CDCl3, δ ppm): 26.72, 27.43, 33.37, 39.78, 43.29, 51.43,
109.39, 118.88, 121.61, 122.28, 122.12, 123.38, 125.28, 126.08, 127.61, 128.32,
129.21, 135.11, 149.69, 153.21, 162.22, 196.68. Anal Calcd for C25H21NO4: C,
75.17; H, 5.30; N, 3.51%. Found: C, 75.22; H, 5.27; N, 3.55%. These spectroscopic
values are shown in electronic supplementary material (ESM 3).
9, 10‑dihydro‑9, 9‑dimethyl‑12‑(6‑methyl‑4‑oxo‑4H‑chromen‑3‑yl)‑8H‑benzo[a]
xanthen‑11(12H)‑one [4j]
IR (υmax, cm−1, KBr): 2953 (C-H), 1679 (C=O), 1655 (C=O), 1621 (C=C);
1HNMR (400 MHz, CDCl3, δ ppm): 0.98 (s, 3H), 1.11 (s, 3H), 2.20 (s, 2H),
2.53 (s, 2H), 5.60 (s, 1H), 6.81–6.93 (m, J=6.4 Hz, 4H), 6.93 (d, J=8.1 Hz, 1H),
7.13–7.31 (m, 3H), 7.43–7.63 (m, 3H); 13CNMR (100 MHz, CDCl3, δ ppm):
24.74, 26.92, 27.47, 31.97, 35.78, 42.22, 51.13, 115.36, 116.18, 117.36, 123.08,
123.11, 124.28, 125.28, 126.48, 127.08, 128.68, 128.86, 134.12, 149.39, 154.26,
164.28, 191.18, 197.48. Anal Calcd for C29H24O4: C, 79.80; H, 5.54%. Found: C,
79.78; H, 5.51%. These spectroscopic values are shown in electronic supplementary
material (ESM 4).
Conclusion
We explored sodium acetate/MWI as an efcient, rapid green protocol for the synthe-
sis of a wide range of pharmaceutically interesting functionalized tetrahydrobenzo[α]
xanthen-11-ones via three-component condensation of dimedone, β-naphthol and
various aromatic aldehydes. Tetrahydrobenzo[α]xanthen-11-ones were evaluated
for their potent antimicrobial activity. The synthesized products 9, 10-dihydro-9,
1 3

P. Mane et al.
9-dimethyl-12-(4-nitrophenyl)-8H-benzo[a]xanthen-11(12H)-one [4b], 9, 10-dihy-
dro-9, 9-dimethyl-12-(2, 4-dichlorophenyl)-8H-benzo[a]xanthen-11(12H)-one [4e],
9, 10-dihydro-9, 9-dimethyl-12-(6-methyl-4-oxo-4H-chromen-3-yl)-8H-benzo[a]
xanthen-11(12H)-one [4j] exhibited excellent antimicrobial activity. The noteworthy
advantages of present protocol are high yield, shorter reaction time, greener condi-
tions and easy work-up.
Acknowledgements Authors are thankful to Department of Chemistry, Yashavantrao Chavan Institute
of Science, Satara, for providing laboratory facilities and also thankful to DBT-STAR Scheme, Research
Advisory Committee for giving seed money.
References
1. G.S. Nyanhongo, T. Kudanga, E. Nugroho Prasetyo, G.M. Guebitz, Adv. Biochem. Eng. Biotechnol.
125, 47 (2011)
2. J.C. Van Hest, D.A. Tirrell, Chem. Commun. 19, 1897 (2001)
3. S. Sonei, M. Gholizadeh, F. Taghavi, Polycycl. Aromat. Compd. (2019). https://doi.
org/10.1080/10406638.2018.1531431
4. A. Maleki, J. Rahimi, Z. Hajizadeh, M. Niksefat, J. Organomet. Chem. 881, 58 (2019)
5. B. Sakram, B. Sonyanaik, K. Ashok, S. Rambabu, S.K. Johnmiya, Res. Chem. Intermed. 42, 1699
(2016)
6. A. Maleki, M. Aghaei, N. Ghamari, Appl. Organomet. Chem. 30, 939 (2016)
7. A. Maleki, P. Ravaghi, M. Aghaei et al., Res. Chem. Intermed. 43, 5485 (2017)
8. C.O. Kappe, Angew. Chem. Int. Ed. 43, 6250 (2004)
9. S.M.S. Chauhan, B.B. Sahoo, K.A. Srinivas, Synth. Commun. 31, 33 (2001)
10. C.R. Strauss, D.W. Rooney, Green Chem. 12, 1340 (2010)
11. S. Caddick, R. Fitzmaurice, Tetrahedron 65, 3325 (2009)
12. B. Shinde, S. Kamble, P. Gaikwad, V. Ghanwat, S. Tanpure, P. Pagare, B. Karale, A. Burungale,
Res. Chem. Intermed. 44, 3097 (2018)
13. B. Shinde, S.B. Kamble, D.M. Pore, P. Gosavi, A. Gaikwad, H.S. Jadhav, B.K. Karale, A.S. Burun-
gale, Chem. Select 3, 13197 (2018)
14. B. Shinde, S.B. Kamble, H.S. Jadhav, B.K. Karale, K.G. Kanade, A.S. Burungale, Chem. Select 3,
13140 (2018)
15. J.J. Li, X.-Y. Tao, Z.H. Zhang, Phosphorus Sulfur 183, 1672 (2008)
16. Z.H. Zhang, P. Zhang, S.H. Yang et al., J. Chem. Sci. 122, 427 (2010)
17. G.-C. Li, J. Chem. Res. 8, 484 (2008)
18. J.J. Li, X.Y. Tao, Z.H. Zhang, Synth. Commun. 38, 4474 (2008)
19. G. Harichandran, S.D. Amalraj, P. Shanmugam, J. Mol. Catal. A Chem. 392, 31 (2014)
20. F. Shirini, N. Ghafari Khaligh, Dyes Pigments 95, 789 (2012)
21. R. Giri, J.R. Goodell, C. Xing, A. Benoit, H. Kaur, H. Hiasa, D.M. Ferguson, Bioorgan. Med.
Chem. 18, 1456 (2000)
22. J.P. Poupelin, G. Saint-Rut, O. Fussard-Blanpin, G. Narcisse, G. Uchida Ernouf, R. Lakroix, Eur. J.
Med. Chem. 13, 67 (1978)
23. J.J. Omolo, M.M. Johnson, S.F. Van Vuuren, C.B. de Koning, Bioorg. Med. Chem. Lett. 21, 7085
(2011)
24. M. Pirouzmand, A.M. Gharehbaba, Z. Ghasemi, S.A. Khaaje, Arab. J. Chem. 10, 1070 (2016)
25. J. Li, W. Tang, L. Lu, W. Su, Tetrahedron Lett. 49, 7117 (2008)
26. B. Maleki, M. Gholizadeh, Z. Sepehr, Bull. Korean Chem. Soc. 32, 1697 (2011)
27. M. Zakeri, M.M. Heravi, M. Saeedi, N. Karimi, H.A. Oskooie, N. Tavakoli-Hoseini, Chin. J. Chem.
29, 1441 (2011)
28. J.T. Li, Y.W. Li, Y.L. Song, Synth. Commun. 42, 2161 (2012)
29. S. Sudha, M.A. Pasha, Ultrason. Sonochem. 19, 994 (2012)
30. R. Heydari, F. Shahrekipour, Res. Chem. Intermed. 41, 4581 (2014)
1 3

Sodium acetate/MWI: a green protocol for the synthesis of…
31. M. Fatahpour, N. Hazeri, M.T. Maghsoodlou et al., Iran. J. Sci. Technol. Trans. Sci. 42, 533 (2018)
32. A. Davoodnia, S. Yadegarian, A. Nakhaei, N. Tavakoli Hoseini, Russ. J. Gen. Chem. 86, 2849
(2016)
33. J. Ma, X. Peng, L. Zhong, R. Sun, New J. Chem. 42, 9140 (2018)
34. J.M. Khurana, D. Magoo, Tetrahedron Lett. 50, 4777 (2009)
35. M. Zakeri, M.M. Heravi, M. Saeedi, N. Karimi, H.A. Oskooie, N. Tavakoli-Hoseini, Chin. J. Chem.
29, 1441 (2011)
36. L. Jianjun, L. Lingmei, S. Weike, Tetrahedron Lett. 51, 2434 (2010)
37. A. Kumar, S. Sharma, R.A. Maurya, J. Sarkar, J. Comb. Chem. 12, 20 (2010)
38. R.Z. Wang, L.F. Zhang, Z.S. Cui, Synth. Commun. 39, 2101 (2009)
39. G.C. Nandi, S. Samai, R. Kumar, M.S. Singh, Tetrahedron 65, 7129 (2009)
40. C.S. Sundar, K.U. Maheswara Rao, N.B. Reddy, S.S. Prasad, C.S. Reddy, Catal. Sci. Technol. 2,
1382 (2012)
41. J. Li, W. Tang, L. Lu, W. Su, Tetrahedron Lett. 49, 7117 (2008)
42. N. Foroughifar, A. Mobinikhaledi, H. Moghanian, R. Mozafari, H.R.M. Esfahani, Synth. Commun.
41, 2663 (2011)
43. A. Kumar, S. Sharma, R.A. Maurya, J. Sarkar, J. Comb. Chem. 12, 20 (2010)
44. B. Bonev, J. Hooper, J. Parisot, J. Antimicrob. Chemoth. 61, 1295 (2008)
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