Efficient One-Pot Three-Component Synthesis of 3,4,5-Substituted Furan-2(5 H)-ones Catalyzed Watermelon Juice

Article abstract of DOI:10.1080/15533174.2014.988230

A simple, efficient, and environmentally benign protocol for the synthesis of 3,4,5-substituted furan-2(5H)-ones has been achieved using extract of watermelon as a natural catalyst. We found, for the first time, that the extract of watermelon could effectively catalyze The condensation reaction of aldehydes, amines, and dialkyl acetylenedicarboxylates to 3,4,5-substituted furan-2(5H)-ones in excellent yields under mild conditions. The low cost, easy availability of the catalyst, and simple reaction conditions suggest the possible use of the present method for large scale preparations.

Full text of DOI:10.1080/15533174.2014.988230

Synthesis and Reactivity in Inorganic, Metal-Organic, and
Nano-Metal Chemistry
ISSN: 1553-3174 (Print) 1553-3182 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt20
Efficient One-pot Three-component Synthesis
of 3,4,5-Substituted Furan-2(5H)-ones Catalyzed
Watermelon Juice
Belghais Adrom, Malek Taher Maghsoodlou, Mojtaba Lashkari, Nourallah
Hazeri & Razieh Doostmohammadi
To cite this article: Belghais Adrom, Malek Taher Maghsoodlou, Mojtaba Lashkari, Nourallah
Hazeri & Razieh Doostmohammadi (2015): Efficient One-pot Three-component Synthesis of
3,4,5-Substituted Furan-2(5H)-ones Catalyzed Watermelon Juice, Synthesis and Reactivity in
Inorganic, Metal-Organic, and Nano-Metal Chemistry, DOI: 10.1080/15533174.2014.988230
To link to this article: http://dx.doi.org/10.1080/15533174.2014.988230
Accepted online: 29 Sep 2015.
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Efficient One-pot Three-component Synthesis of 3,4,5-Substituted Furan-2(5H)-ones
Catalyzed Watermelon Juice
Belghais Adrom, Malek Taher Maghsoodlou*, Mojtaba Lashkari, Nourallah Hazeri,
Razieh Doostmohammadi
Department of Chemistry, Faculty of Science, University of Sistan & Baluchestan, P. O. Box
98135-674 Zahedan, Iran
*Corresponding author e-mail:
mt_maghsoodlou@chem.usb.ac.ir , mt_maghsoodlou@yahoo.com
Abstract
A simple, efficient, and environmentally- benign protocol for the synthesis of 3,4,5-substituted
furan-2(5H)-ones has been achieved using extract of watermelon as a natural catalyst. We found,
for the first time, that the extract of watermelon could effectively catalyze The condensation
reaction of aldehydes, amines, dialkyl acetylenedicarboxylates to 3,4,5-substituted furan-2(5H)-
ones in excellent yields under mild conditions. The low cost, easy availability of the catalyst, and
simple reaction conditions suggest the possible use of the present method for large scale
preparations.
Key word: watermelon juice, dialkyl acetylenedicarboxylates, furan-2(5H)-ones, aldehydes
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Introduction
New catalytic synthetic methods in organic chemistry which satisfy increasingly stringent
environmental constraints are in great demand by the pharmaceutical and chemical industries. In
addition, novel catalytic procedures are necessary to produce the emerging classes of organic
compounds becoming the targets of molecular and biomedical research. Several types of
substances such as enzymes, surfactants, ionic liquids, clays, and supercritical solvents are now
widely recognized as practical alternatives to traditional organic synthesis and as convenient
solutions to certain intractable synthetic problems. This is due to problems associated with
prevailing catalysts, such as hazardous nature, expense, difficult handling, tedious workup,
requirements of hazardous organic solvents, elevated temperature conditions, and ,above all,
adverse effects on the environment. In an attempt to circumvent these disadvantages, we looked
to nature for help. Nature provides a fantastic array of catalysts extremely well suited to support
life such as intact plant systems which represent a unique class of potential biocatalysts for the
reactions of various organic substrates [1- 3] .
The synthetic transformations are more efficient using these materials and they generate less
waste than the conventional chemical methods. More recently, chemical reactions using plant
cell cultures and part of plants as biocatalysts have received great attention [4-6]. This crescent
interest is due to the wide biotechnological potential of the enzymetic reactions. The
biocatalytical transformations using plant root [7,8], plant tubers [9], edible plants [10] and
plants` leave [11] extract can be applied in a considerable number of organic reactions. Fruit
juice is also naturally occurring used as a biocatalysts in organic synthesis. Fruit juice is now
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routinely being used in organic synthesis as homogeneous catalysts for various selective
transformations of simple and complex molecules.
These interesting properties of aqueous extract of fruit allow us to use watermelon juice as an
eco-friendly catalyst for organic synthesis. Considering the widespread utility of furan one
derivatives and availability of few literature protocols for the synthesis of furanones and their
limitations, in the present work we have successfully developed a synthetic route with minimized
drawbacks.
Among the available methods for the construction of furanones, the nucleophilic reaction
between zwitterions of amine and dialkyl acetylenedicarboxylates with aldehyde is the most
convenient one [12-16]. The three-component condensation of aldehydes, amines and dialkyl
acetylenedicarboxylates lead to the formation of 3,4,5-substituted furan-2(5H)-one derivatives
(Scheme 1).
Results and discussion
Continuing of our work, following the principles of green chemistry [17-20], we have developed
a simple, efficient, and green protocol for the preparation of 3,4,5-substituted furan-2(5H)-one
using extract of watermelon as a green and inexpensive catalyst as well as solvent. Our approach
reduces the use of hazardous organic solvents and it uses simple and mild conditions with
inherently lower costs.
Watermelon is one of the main vegetable crops grown and consumed all over the Mediterranean
basin. China is the largest producer of watermelon, with 68.9% of the total production. It is much
appreciated as an excellent refreshing summer fruit. Besides vitamins, mineral salts and specific
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amino acids watermelon provide a wide variety of dietary antioxidants such as carotenoids and
phenolics. The edible portion contains approximately 6.2 % total sugar and 91.0% water by
weight (21-25).
Soluble sugars in content of the watermelon are one of its most important properties, as the value
of the watermelon is dependent on this content. The sugars was applied as an efficient and
homogenous catalyst for multicomponent reaction in excellent yields (20,26). Our further
experiments have been designed to check the activities of some components of watermelon juice
on synthesis of 3,4,5-substituted furan-2(5H)-one. For this purpose in separate experiments,
components with more weight percentage such as sucrose, glucose, fructose, vitamin C, and
vitamin B-6 were chosen. Investigations have shown that the reaction has occurred in presence
of all above component with good yield. Since the juice contains a substantial number of
vitamins, ions and reduces sugars with different ratio and varies, regarding to mentioned
experiment, it seems that set of above agents are effective in occurring of these three component
reactions.
In the beginning, a test reaction using benzaldehyde 1 (1.0 mmol), aniline 2 (1.0 mmol), and
dimethyl acetylenedicarboxylate 3 (1.0 mmol) in 5 mL juice of watermelon at room temperature
was performed in order to establish the real effectiveness of the catalyst (solvent), and the
product was obtained in good yields.
In order to compare the strength of the juice of watermelon, as a catalyst with juice of various
summer fruits, a model reaction was carried out between 1 (1.0 mmol), aniline 2 (1.0 mmol) and
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dimethyl acetylenedicarboxylate 3 (1.0 mmol) using various juices of fruits as catalysts at room
temperature, and the results are summarized in Table 2.
Under the optimized reaction conditions, the generality of the reaction was investigated by the
usage of various aldehydes, anilines and dialkyl acetylenedicarboxylate to produce furan-2(5H)-
one derivatives. The results are summarized in Table 3. These results indicate the effectiveness
of electron-withdrawing and electron-donating groups on the time and yield of the reaction.
Benzaldehydes with electron-withdrawing groups react with aniline better than electron-donating
groups for generation of furan-2(5H)-ones in good to high yields. In our research work, aliphatic
aldehyde and amine such as propanal and 1-buthylamin did not tolerate the reaction.
1
The structures of new compounds in Table 3 were deduced on the basis of IR, H, and 13C NMR
spectroscopy, mass spectrometry, and elemental analysis. The mass spectrum of Compound 4m,
ethyl 4-(3-nitrophenylamino)-2,5-dihydro-5-oxo-2-phenylfuran-3-carboxylate displayed the
1
molecular ion peak at m/z = 368, consistent with the proposed structure. The H NMR spectrum
of this product, exhibited a triplet at δ = 1.22 ppm and quartet at δ = 4.23 ppm for ethyl protons
of the carboxylate group and one sharp singlet arising from benzylic proton at δ = 5.83 ppm. The
aromatic protons of product were observed at δ = 7.31-8.34 ppm. A broad singlet for the NH
group at δ = 9.15 ppm indicated intra-molecular hydrogen bond formation with the vicinal
carbonyl group. The 13C NMR spectrum of this product showed 17 distinct resonances in
agreement with the proposed structure. The IR spectrum indicated one sharp peak at 3308 cm-1
for NH within product. A proposed mechanism for this transformation can be combination of
nucleophilic Michael addition, iminium-enamine tautomerization with γ-Lactonization (27,28).
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To compare the applicability and efficiency of watermelon juice with the reported catalysts in the
literature for the synthesis of 3,4,5-substituted furan-2(5H)-ones, we have tabulated the results of
these catalysts in Table 4. As shown in Table 4, watermelon juice can act as an efficient catalyst
with respect to reaction time and yield of products.
In conclusion, we have found that the aqueous extract of watermelon is considered as an
efficient, economical, and environmentally- friendly catalyst for the synthesis of 3,4,5-
substituted furan-2(5H)-ones. The high yield of products in a short reaction time along with high
purity, mild reaction conditions, and a simple workup procedure makes this procedure attractive.
Using watermelon juice as a solvent and biodegradable catalyst is the attractive features of this
protocol. Furnishing pure products by simple filtration makes an aqueous approach possible for
large scale preparation of furan-2(5H)-ones.
EXPERIMENTAL
Melting points and IR spectra of all compounds were measured on an Electrothermal 9100
apparatus and a JASCO FTIR 460 Plus spectrometer, respectively. The 1H and 13C NMR spectra
were obtained on Bruker DRX-400 Avance instruments with CDCl3 as a solvent. Mass spectra
were recorded on an Agilent Technology (HP) spectrometer operating at an ionization potential
of 70 eV. Samples of fruits were blended using a laboratory electrical blender (Model 32BL79,
Waring, USA). All reagents and solvents obtained from Fluka and Merck were used without
further purification.
General procedure:
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Plant material
Eight fruit samples were purchased from local commercial market, collected between July and
August (2013) in the region of South of Sistan and Baluchestan, Iran. After samples were
purchased, they were washed and drained. The skins were peeled except Blackberry and the rest
of the fruit was cut into 3 cm cubes. The seeds were then removed and all the flesh part was
blended using a laboratory electrical blender (Model 32BL79, Waring, USA). The obtained juice
was vacuum- filtered and then transferred into a beaker.
General procedure for the synthesis of furan-2(5H)-one derivatives
The mixture of aldehyde (1.0 mmol), amine (1.0 mmol), dialkylacetylenedicarboxylate (1.0
mmol) and 5 mL juice of watermelon were stirred at room temperature. After completion of the
reaction (monitored by thin-layer chromatography, TLC), the reaction products were collected
by filtration. After that, the products were washed with water/ethanol (50:50, 3 × 2 mL) to give
the corresponding pure compounds. The catalyst remained in the water/ethanol filtrate.
Ethyl-4-(3-nitrophenylamino)-2,5-dihydro-5-oxo-2-phenylfuran-3-carboxylate (4m):
Colorless solid; 0.258 g (70%); mp 208 °C; IR (KBr): 3308, 3093, 2984, 1723, 1686, 1526 cm–1;
1H NMR (400 MHz, CDCl3) δ: 1.22 (t, J = 7.2 Hz ,CH3), 4.23 (q, J=7.2 Hz, CH2), 5.83 (s, 1H,
Hbenzylic), 7.31-8.34 (m, 9H, HAr), 8.341 (s, 1H), 9.158 (br, 1H, NH); 13C NMR (100 MHz,
CDCl3) δ: 165.1 and 162.9 (ester C=O), 156.2, 148.4, 137.5, 134.1, 129.9, 129.0, 129.0, 127.4,
127.2, 120.0, 115.9, 113.7 (12 CAr and Cvinyl), 61.6 (Cbenzylic), 61.2 (CH2), 13.9 (CH3). MS m/z
(%): 57 (15), 73 (16), 84 (20), 96 (21), 97 (22), 98 (20), 129 (15), 130 (21), 203 (24), 236 (21),
295 (59), 368 (M+, 100).
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tert-Butyl-2,5-dihydro-5-oxo-4-(phenylamino)-2-p-tolylfuran-3-carboxylate (4n):
Colorless solid; 0.268 g (83%); mp 175-178 °C; IR (KBr): 3400, 3020, 2925, 1701, 1670 cm–
1.1H NMR (400 MHz, CDCl3) δ: 1.38 (s, 9H, CH3), 2.28 (s, 3H, CH3), 5.64 (s, 1H, Hbenzylic),
7.04-7.50 (m, 9H, HAr), 9.29 (br, 1H, NH); 13C NMR (100 MHz, CDCl3) δ: 165.1 and 162.9
(ester C=O), 156.7, 138.1, 136.4, 132.1, 129.1, 128.9, 127.4, 125.6, 122.3 and 114.5 (CAr), 83.2
(C-O), 61.4 (Cbenzylic), 28.0 (3 CH3), 21.1 (CH3). MS m/z (%): 57 (44), 77 (33), 91 (27), 115 (58),
144 (99), 189 (100), 264 (61), 291 (19), 309 (94), 365 (M+, 50).
Acknowledgement
We gratefully acknowledge financial support from the Research Council of the University of
Sistan and Baluchestan.
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Table 1. Some of the chemical composition of watermelon juice
Entr
y
Soluble
sugars
Organic
acids
Volatiles
Carotenoids
Vitamins
Mineral
s
1
2
3
Fructose
Glucose
Sucrose
Oxalic acid
Malic acid
Pentyl-furan
Limonene
Nonanal
trans violaxanthin
Luteoxanthin
Vitamin A
Thiamine
Riboflavin
K
P
Tartaric
acid
9-cis-
Violaxanthin
Fe
4
5
6
Citric acid
1,10-Undecadiene
(Z)-3-Nonen-1-ol
All-trans lutein
Niacin
Na
Ca
Quinic acid
All-trans
zeaxanthin
Ascorbic
Acid
Vitamin B6
(E,Z)-3,6-Nonadien- Phytofluene A 3
1-ol
7
(E)-2-Nonenal
2,6-Nonadien-1-ol
3-NO2-C6H4
Nonanol
Phytoene
Phytofluene B
α-Carotene
8
9
10
11
12
δ-Carotene
Nonanoic acid
β-Ionon
β-Carotene
cis-β-Carotene
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Table 2. catalyst screening for the synthesis of furan-2(5H)-ones
at room temperature.
Entry
Solvent
pH
6.8
5.8
3.9
2.9
3
Time (h) Yield (%)a
-
1
2
3
4
5
6
7
8
9
H2O
24
6
Melon juice
50
25
40
25
-
Blackberry juice
Grapes juice
15
12
15
24
10
16
3
Pomegranate juice
Strawberries juice
Peach juice
3.2
3.30
3.5
5.6
42
38
92
Verjuice juice
Watermelon juice
a Isolated yield.
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Table 3. Synthesis of furan-2(5H)-one derivatives.
Entr
y
R1
R2
R3
Time
(h)
Yield (%)a Product Ref.
1
2
3
4
5
6
7
8
Ph
Ph
CH3
CH3
4-F-C6H4
2
3
3
2
2
2
1
3
70
69
82
90
92
88
85
85
13
17
17
17
12
12
12
12
4a
4b
4c
4d
4e
4f
4-Cl-C6H4
Ph
CH3
3-NO2-C6H4
4-NO2-C6H4
Ph
CH3
Ph
Ph
Ph
Ph
Ph
CH3CH2
CH3CH2
CH3CH2
CH3CH2
4-Me-C6H4
4-Cl-C6H4
4g
4h
4-OMe-
C6H4
9
1- naphtyl
Ph
CH3CH2
CH3
Ph
3-NO2-C6H4
Ph
1
2
3
90
93
60
17
17
12
4i
4j
10
11
4-OMe-
C6H4
CH3
4k
12
13
14
15
Ph
Ph
CH3CH2
4-Me-C6H4
3
2
2
2
77
80
90
90
12
b
4l
4m
4n
4o
CH3CH2 3-NO2-C6H4
4-Me-C6H4 tert-buthyl
Ph CH3
Ph
Ph
b
13
a Isolated yield.
b
The new compounds were synthesized in this work. All known products previously
reported in the literature were characterized by comparison of m.p., IR and NMR spectra
with those of authentic samples.
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Table 4 Comparison result of watermelon juice with the reported catalysts
in literature for the synthesis of 3,4,5-substituted furan-2(5H)-ones 4o and
4e.
Entry Product Catalyst
Time
Yield
(%)
-
Ref.
1
2
3
4
5
6
7
8
9
β-Cyclodextrin
Nano-ZnO
Al(HSO4)3
SnCl2.2H2O
AcOH
-
12
4o
2.5 h
8 h
6.5 h
-
94
84
90
-
15
14
13
17
[Bu4N][HSO4]
PPA/SiO2
Sucrose
5 h
1 h
9 h
2h
92
90
97
90
18
19
25
watermelon
juice
This work
10
11
12
13
14
15
16
17
18
β-Cyclodextrin
Nano-ZnO
Al(HSO4)3
SnCl2.2H2O
AcOH
12 h
-
85
-
12
4e
15
9 h
-
77
-
14
13
1 h
2 h
1 h
4.5 h
2h
95
90
91
85
92
17
[Bu4N][HSO4]
PPA/SiO2
Sucrose
18
19
25
watermelon
juice
This work
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OR2
O
O
R2O
O
HN
H2N
C
C
R3
R3
H
+
Watermelon juice
r.t.
O
O
+
R1
O
3
R2O
2
4a-n
R1
1
Scheme 1. Synthesis of furan-2(5H)-one derivatives.
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