One-pot, three-component synthesis of 4H-pyrans using cu(II) oxymetasilicate

Article abstract of DOI:10.1080/00397910902796102

4H-Pyrans are synthesized through one-pot, three-component reaction of benzaldehyde, malononitrile, and ethyl acetoacetate using Cu(II) oxymetasilicate as an efficient, reusable catalyst. The procedure offers advantages in terms of better yields, short re

Full text of DOI:10.1080/00397910902796102

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One-Pot, Three-Component
Synthesis of 4H-Pyrans Using
Cu(II) Oxymetasilicate
Majid M. Heravi a , Yahya S. Beheshtiha a , Zahra
Pirnia a , Samaheh Sadjadi a & Mina Adibi b
a Department of Chemistry, School of Sciences,
Azzahra University, Vanak, Tehran, Iran
b Specialty Chemicals Research Department,
Chemical and Petrochemical Division, Research
Institute of Petroleum Industry, NIOC, Tehran, Iran
Published online: 08 Sep 2009.
To cite this article: Majid M. Heravi , Yahya S. Beheshtiha , Zahra Pirnia , Samaheh
Sadjadi & Mina Adibi (2009): One-Pot, Three-Component Synthesis of 4H-Pyrans Using
Cu(II) Oxymetasilicate, Synthetic Communications: An International Journal for Rapid
Communication of Synthetic Organic Chemistry, 39:20, 3663-3667
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Synthetic Communications1, 39: 3663–3667, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910902796102
One-Pot, Three-Component Synthesis
of 4H-Pyrans Using Cu(II) Oxymetasilicate
Majid M. Heravi,1 Yahya S. Beheshtiha,1 Zahra Pirnia,1
Samaheh Sadjadi,1 and Mina Adibi2
1Department of Chemistry, School of Sciences, Azzahra University,
Vanak, Tehran, Iran
2Specialty Chemicals Research Department, Chemical and Petrochemical
Division, Research Institute of Petroleum Industry, NIOC, Tehran, Iran
Abstract: 4H-Pyrans are synthesized through one-pot, three-component reaction
of benzaldehyde, malononitrile, and ethyl acetoacetate using Cu(II) oxymetasili-
cate as an efficient, reusable catalyst. The procedure offers advantages in terms of
better yields, short reaction times, mild reaction conditions, and reusability of the
catalyst.
Keywords: Cu(II) oxymetasilicate, 4H-pyrans, recyclable catalyst
INTRODUCTION
Polyfunctionlized 4H-pyrans are interesting compounds because they
possess biological and pharmacological activities.[1] These compounds
are used as anticoagulants, anticancer agents, spasmolytics, and anti-
anaphylactics.[2,3] 4H-Pyrans containing heterocyclic rings show more
pharmacological activities.[4] These compounds can be used for the
treatment of neurodegenerative diseases, including Alzheimer’s disease,
as well as for the treatment of schizophrenia and myoclonus. 2-Amino-4-
H-pyran derivatives are useful as photoactive materials.[5] The 4H-pyran
Received January 11, 2009.
Address correspondence to Majid M. Heravi, Department of Chemistry,
School of Sciences, Azzahra University, Vanak, Tehran 1234, Iran. E-mail:
mmh1331@yahoo.com
3663

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M. M. Heravi et al.
Scheme 1. Synthesis of 4H-pyrans using Cu(II) oxymetasilicate.
unit has been synthesized using different methods, including microwave
and ultrasonic irradiation.[6] In addition, the one-pot synthesis of 4H-
pyrans has been reported using tetrabutylammonium bromide,[7]
(S)-proline, rare-earth perfluorooctanoates, and hexadecyltrimethylam-
monium bromide.[8] All of these catalysts have limitations such as harsh
reaction conditions, poor yields, tedious workups, and poor recyclability.
Herein we report the synthesis of 4H-pyrans from a one-pot reaction
of benzaldehyde, malononitrile, and ethyl acetoacetate in the presence of
catalytic amounts of Cu(II) oxymetasilicate (Scheme 1).
Cu(II) oxymetasilicate has been used successfully for the synthesis of
4H-pyrans through the one-pot, three-component reaction of benzalde-
hyde, malononitrile, and ethyl acetoacetate. The results of synthesis of
4H-pyrans in the presence of catalytic amounts of Cu(II) oxymetasilicate
are summarized in Table 1. As shown in this table, benzaldehyde with
electron-withdrawing groups led to products with slightly better yields
than benzaldehyde with electron-donating groups.
To investigate the effect of catalyst amounts on the yields of reac-
tions, two reactions were selected as model reactions. Various amounts
Table 1. Synthesis of 4H-pyrans using Cu(II)
oxymetasilicate under refluxing condition
Entry
R
Yield (%)a
1
2
3
4
5
6
7
H
88
92
91
92
85
83
84
4-NO2
3-NO2
4-Cl
4-OMe
4-Me
4-OH
aYields refer to isolated products.

One-Pot Synthesis of 4H-Pyrans
3665
Table 2. Results of using different amounts of Cu(II)
oxymetasilicate on yields of two 4H-pyrans
Catalyst amount
(mol%)
Yield
(%)a
Entry
R
1
2
3
4
5
6
H
H
H
4-NO2
4-NO2
4-NO2
0.1
0.3
0.5
0.1
0.3
0.5
84
88
88
89
92
92
aYields refer to isolated products.
of catalysts (0.1, 0.3, and 0.5 mol%) were used for the synthesis of these
two model reactions. The results are shown in Table 2. The results show
that the optimum amount of catalyst was 0.3 mol%.
To study the effect of solvent on this reaction, the model reactions
were performed in four solvents including CH3CN, CH2Cl2, CHCl3,
and H2O. The results are summarized in Table 3. As shown in this table,
CH3CN is the best solvent for this reaction.
In summary, we have developed a method using Cu(II) oxymetasili-
cate for the synthesis of 4-H-pyrans from the one-pot, three-component
reaction of benzaldehyde, malononitrile, and ethyl acetoacetate. The rea-
sonable reaction times, very good yields, simple workup procedure, and
environmentally friendly conditions are the main merits of this method.
Table 3. Effect of various solvents on yield of two
4H-pyran derivatives
Yield
(%)a
Entry
R
Solvent
2
3
4
5
6
7
8
9
H
H
H
CH3CN
CH2Cl2
CHCl3
H2O
CH3CN
CH2Cl2
CHCl3
H2O
88
85
82
80
92
90
89
87
H
4-NO2
4-NO2
4-NO2
4-NO2
aYields refer to isolated products.

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M. M. Heravi et al.
EXPERIMENTAL
All the chemicals were purchased from Merck Company. Cu(II)
oxymetasilicate was prepared according to our previous work.[9] All
compounds were known, and their physical data were compared with
those of authentic compounds and found to be identical.
Synthesis of 4H-Pyran Derivatives: General Procedure
A catalytic amount of Cu(II) oxymetasilicate (0.3 mmol) was added to a
mixture of benzaldehyde (10 mmol), malononitrile (12 mmol), and ethyl
acetoacetate (10 mmol), and the mixture was refluxed in CH3CN
(10 mL) for 1 h. The progress of the reaction was monitored by thin-layer
chromatography (TLC). At the end of the reaction, the catalyst was
filtered off and the products were recrystallized from an ethanol mixture.
All products were identified by comparison of their physical and
spectroscopic data with those reported for authentic samples.[8]
Recycling of the Catalyst
At the end of the reaction, the catalyst could be recovered by simple
filtration. The recycled catalyst could be washed with dichloromethane
(DCM) and subjected to a second run of the reaction process. In
Table 4, the comparison of efficiency of this catalyst in synthesis of
Table 4. Comparison of efficiency of Cu(II)
oxymetasilicate in synthesis of 4H-pyrans after
three times (given in percentage of yield)
Runa
Entry
R
First
Second
Third
1
2
3
4
5
6
7
H
88
92
91
92
85
83
84
86
90
90
91
84
82
83
86
90
89
90
83
82
82
4-NO2
3-NO2
4-Cl
4-OMe
4-Me
4-OH
aYields refer to isolated products.

One-Pot Synthesis of 4H-Pyrans
3667
4H-pyrans after three times is reported. As shown in Table 4, the yields of
reactions after using this catalyst three times show a slight reduction.
ACKNOWLEDGEMENTS
The authors are thankful to Azzahra University Research Council for
partial financial support.
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