Simple green approach to the synthesis of 2-amino-5-oxo-4,5- dihydropyrano[3,2-c]chromene-3-carbonitrile derivatives catalyzed by 3-hydroxypropanaminium acetate (HPAA) as a new ionic liquid

Article abstract of DOI:10.1007/BF03249089

A new ionic liquid, 3-hydroxypropanaminium acetate (HPAA) [H ₃N⁺-CH₂-CH₂-CH₂-OH] [CH₃COO^-], was synthesized for the first time and used as an efficient and recoverable catalyst i

Full text of DOI:10.1007/BF03249089

J. Iran. Chem. Soc., Vol. 8, No. 2, June 2011, pp. 545-552.
JOURNAL OF THE
Iranian
Chemical Society
A Simple Green Approach to the Synthesis of 2-Amino-5-oxo-4,5-dihydropyrano[3,2-
c]chromene-3-carbonitrile Derivatives Catalyzed by 3-Hydroxypropanaminium
Acetate (HPAA) as a New Ionic Liquid
H.R. Shaterian* and A.R. Oveisi
Department of Chemistry, Faculty of Sciences, the University of Sistan and Baluchestan, P.O. Box 98135-674,
Zahedan, Iran
(Received 19 September 2010, Accepted 29 October 2010)
A new ionic liquid, 3-hydroxypropanaminium acetate (HPAA) [H3N+-CH2-CH2-CH2-OH][CH3COO-], was synthesized for the
first time and used as an efficient and recoverable catalyst in the synthesis of 2-amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-
3-carbonitrile derivatives by condensing together 4-hydroxycoumarin, aldehydes and malononitrile at room temperature. The
catalyst can be reused for four times without noticeable loss of activity.
Keywords: 2-Amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitrile, Ionic liquid, Multi-component reaction, Catalysis
INTRODUCTION
friendly, reusable and alternative reaction media in organic
synthesis because of their unique properties such as high
thermal and chemical stability, negligible vapor pressure, no
flammability, high loading capacity and excellent electrical
conductivity [9-12]. Ionic liquids have shown great promise
not only as alternative green solvents, but also as reagents or
catalysts in organic transformations [9,13-20].
Green chemistry is destined to be of global concern in the
near future. In this context, a convenient and rapid synthetic
procedure is highly desirable. To be of practical value, such a
procedure should be suitable for large-scale operations as well
[21]. The pioneering work of Toda et al. has shown that many
reactions (but not all) can be produced in high yields just by
grinding solids together [22,23]. Traditionally, these reactions
were carried out on a very small scale in an agate mortar and
pestle. To conduct grindstone chemistry on a large scale a
simple and inexpensive expedient is to use a hand-held electric
food mixer with stainless steel rotors for grinding the reagents
in a large glass or porcelain bowl [21].
Multi-component reactions (MCRs) are very important in
organic synthesis due to the formation of carbon-carbon and
carbon-hetero atom bonds in one pot [1-3]. Simple procedures,
high bond forming efficiency, time and energy saving and low
expenditures are among the advantages of these reactions [4].
Recently, Shaabani et al. reported the synthesis of
functionalized benzo[g]- and dihydropyrano[2,3-g]chromene
derivatives via a novel one-pot three- and pseudo-five-
component reaction [5].
Ionic liquids are salts consisting of ions, which exist in the
liquid state at ambient temperatures [6]. Although the first
ionic liquid, ethylammonium nitrate (m.p.: 12 °C) was
reported as early as 1914 [7], ionic liquids have gained great
significance only recently. More than 40 reviews have been
published on ionic liquids between 2003 and 2008 [8]. The use
of ionic liquids has received special attention for being eco-
*Corresponding author. E-mail: hrshaterian@chem.usb.ac.ir
Pyrano[3,2-c]chromene derivatives belong to a class of

Shaterian & Oveisi
NH2
OH
O
CN
R
CN
CN
HOCH2CH2CH2NH3 OAc
pulverize, r.t.
O
O
RCHO
+
+
O
R: aryl, alkyl, heterocycl
O
Scheme 1. Synthesis of 2-amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitrile derivatives
important heterocycles with a wide range of biological
properties [24] such as spasmolytic, diuretic, anticoagulant,
anti-cancer, and anti-anaphylactic activity [25]. In addition,
aminochromene derivatives exhibit a wide spectrum of
biological activities including antihypertensive and anti-
ischemic behavior [26-28]. Also, a number of 2-amino-4H-
pyrans are useful as photoactive materials [29].
MHz instrument. The spectra were measured in DMSO
relative to TMS (0.00 ppm). IR spectra were recorded on a
JASCO FT-IR 460 plus spectrophotometer. Mass spectra were
recorded on an Agilent technologies 5973 network mass
selective detector (MSD) operating at an ionization potential
of 70 eV. Conductivities were measured by a WTW Multiline
P3 with TetraCon 325 electrode. Cyclic Voltammetry (CV)
traces were obtained by an EG and G Parstat 2263 model
potentiostat-galvanostat. Thermo-gravimetric Analysis (TGA)
(which was performed by a Shimadzu TG-50 at 10 °C min-1.
heating rate, under nitrogen flow, 23 ml min-1) curve shows a
sharp decline around 150 °C and an inflection at about 190 °C.
Hundred percent mass losses occur at 277 °C. Melting points
were determined in open capillaries with a BUCHI 510
melting point apparatus. TLC was performed on silica-gel
polygram SILG/UV 254 plates.
2-Amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-
carbonitriles have previously been prepared in the presence of
organic bases like piperidine or pyridine in an organic solvent
i.e. ethanol and pyridine [30]. They have also been prepared in
the presence of diammonium hydrogen phosphate in aqueous
ethanol [31] and K2CO3 under microwave irradiation [32].
Some of the reported procedures require long reaction times,
multi-step reactions and complex synthetic pathways, having
drawbacks such as modest yields, and non-reusability of the
catalyst
[33-39].
Also, 1,1,3,3-N,N,N',N'-tetramethyl-
guanidinium trifluoroacetate (TMGT) as an ionic liquid was
used for the preparation of this class of compounds [40].
In continuation of our work [41-46], here we wish to report
a new room temperature task-specific ionic liquid, 3-
hydroxypropanaminium acetate (HPAA) as an efficient and
reusable catalyst for one-pot synthesis of 2-amino-5-oxo-4,5-
dihydropyrano[3,2-c]chromene-3-carbonitriles derivatives by
‘Grindstone Chemistry’ (Scheme 1).
Preparation of Task-Specific Ionic Liquid (HPAA)
To a 250 ml three-necked flask was added 30.5 g (0.5 mol)
of 3-propanolamine and 25 ml of ethanol. To the solution 30 g
(0.5 mol) of acetic acid in 25 ml of ethanol was added
dropwise at room temperature within 60 min with magnetic
stirring. The resultant solution was stirred at room temperature
for 24 h. Ethanol was removed and the oil residual was dried
in vacuo at 50 °C for 48 h to give [H3N+-CH2-CH2-CH2-OH]
1
[CH3COO-] as a colorless, viscous liquid. H NMR (DMSO-
EXPERIMENTAL
d6, 500 Hz): δ 1.52-1.67 (m, 5H, CH3-COO, -CH2-), 2.79 (t,
J = 7.40 Hz, 2H, -O-CH2-), 3.41 (t, J = 6.10 Hz, 2H, -CH2-N),
4.24-4.82 (broad singlet, 4H, -NH3 , -OH) ppm; 13C NMR
+
Materials
All reagents were purchased from Merck and Sigma-
Aldrich and used without further purification. All yields refer
to isolated products after purification. Products were
characterized by comparing the physical data with those of
authentic samples and spectroscopic (IR and NMR) data. The
NMR spectra were recorded on a Bruker Avance DPX 500
(DMSO-d6, 125 Hz): δ 22.8 (CH3-), 28.5 (-CH2-), 36.7 (-CH2-
N), 58.3 (-CH2-O), 180.5 (-CO2-) ppm.
FT-IR spectrum showed a broad band in the 3700-2300
cm-1 that is indicative of zwitterionic quaternary ammonium
carboxylates character. The OH stretching vibration is
embedded in this band. A broad band centered at 1628 cm-1 is
546

A Simple Green Approach to the Synthesis of
a combined band of the carbonyl stretching and N-H plane
95
94
92
100
90
80
70
60
50
40
30
20
10
0
90
bending vibrations. Literature survey confirms this
interpretation as beingconsistent with [H3N+-CH2-CH2-OH]
[HCOO-] [47].
General Procedure for the Synthesis of 2-Amino-5-
oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbo-
nitrile Derivatives Catalyzed by 3-Hydroxypropan-
aminium Acetate
1
2
3
4
A mixture of aldehydes (3 mmol), malononitrile (3 mmol)
and 4-hydroxycoumarin (3 mmol) in the presence of 6 drops
(0.12 g) of ionic liquid was pulverized in a mortar at room
temperature for appropriate time (Table 2). The reaction was
monitored by TLC. After completion of the reaction, H2O was
added and the mixture was filtered to separate the ionic liquid.
The solvent (H2O) was evaporated under reduced pressure and
the ionic liquid was recovered and reused (Fig. 1). For the
purification of the product, the precipitate was washed with
aqueous ethanol or recrystallized from EtOH/H2O to give the
pure products. All the desired products were characterized by
comparing their physical data with those of the known
compounds [31,48-50]. Characterization data for the new
products are given below.
Run. NO.
Fig. 1. The reusability of the catalyst.
125 Hz): δ 36.6, 57.5, 103.2, 112.9, 113.8, 113.9, 114.4,
114.5, 116.4, 119.0, 122.5, 123.7, 124.5, 130.3, 130.3, 132.8,
146.1, 146.2, 152.1, 153.6, 157.9, 159.5, 161.2, 163.1 ppm; IR
(KBr, cm-1): 3375, 3315, 3191, 2195, 1711, 1675, 1619, 1489,
1370, 1252, 1062, 763; MS (EI, 70 eV) m/z (%) = 334 (M+,
22), 267 (13), 239 (100), 121 (21), 92 (8). Anal. Calcd. for
C19H11FN2O3: C, 68.26; H, 3.32; N, 8.38%. Found: C, 68.35;
H, 3.30; N, 8.40%.
2-Amino-5-oxo-4-phenethyl-4,5-dihydropyrano[3,2-c]
chromene-3-carbonitrile (Table 2, entry 14). 1H NMR
(DMSO-d6, 500 Hz): δ 1.81-1.88 (m, 1H, CH2), 2.08-2.17 (m,
1H, CH2), 2.44-2.62 (m, 2H, CH2), 3.50 (t, J = 4.3 Hz, 1H,
CH), 7.00 (t, J = 8.1 Hz, 1H, Ar), 7.08 (d, J = 7.0 Hz, 2H, Ar),
7.13 (t, J =7.5 Hz, 3H, Ar), 7.34-7.45 (m, 4H, NH2 & Ar),
7.62-7.67 (m, 1H, Ar), 7.76 (dd, J = 5.9, 1.2 Hz, 1H, Ar) ppm;
13C NMR (DMSO-d6, 125 Hz): δ 30.3, 30.7, 34.6, 54.8, 103.7,
112.9, 116.3, 119.5, 122.1, 124.3, 125.5, 127.9, 128.1, 132.5,
141.2, 152.0, 154.0, 159.4, 159.8 ppm; IR (KBr, cm-1): 3382,
3315, 3189, 2198, 1694, 1671, 1608, 1396, 1315, 1179, 1211,
1112, 759; MS (EI, 70 eV) m/z (%) = 344 (M+, 7), 240 (20),
239 (100), 187 (8), 138 (21), 91 (10), 43 (17). Anal. Calcd. for
C21H16N2O3: C, 73.24; H, 4.68; N, 8.13%. Found: C, 73.28; H,
4.70; N, 8.20%.
2-Amino-5-oxo-4-o-tolyl-4,5-dihydropyrano[3,2-c]
chromene-3-carbonitrile (Table 2, entry 16). 1H NMR
(DMSO-d6, 500 Hz): δ 2.48 (s, 3H, CH3), 4.73 (s, 1H, CH),
6.90-7.20 (m, 4H, Ar), 7.34 (s, 2H, NH2), 7.41 (d, J = 8.3 Hz,
1H, Ar), 7.46 (t, J = 7.6 Hz, 1H, Ar), 7.66-7.73 (m, 1H, Ar),
7.89 (d, J = 7.8 Hz, 1H, Ar) ppm; 13C NMR (DMSO-d6, 125
Hz): δ 19.0, 32.4, 57.9, 104.5, 122.8, 116.4, 119.1, 122.3,
124.6, 126.6, 126.7, 127.8, 130.0, 132.7, 135.2, 142.2, 152.0,
153.4, 157.7, 159.5 ppm; IR (KBr, cm-1): 3400, 3283, 3179,
2202, 1709, 1675, 1637, 1603, 1490, 1457, 1377, 1171, 1059,
957, 753; MS (EI, 70 eV) m/z (%) = 330 (M+, 18), 249 (24),
240 (17), 239 (100), 121 (21). Anal. Calcd. for C20H14N2O3: C,
72.72; H, 4.27; N, 8.48%. Found: C, 72.80; H, 4.30; N, 8.50%.
2-Amino-5-oxo-4-(pyridin-2-yl)-4,5-dihydropyrano[3,2-
1
c]chromene-3-carbonitrile (Table 2, entry 17). H NMR
2-Amino-4-(3-flourophenyl)-5-oxo-4,5-dihydropyrano
[3,2-c] chromene-3-carbonitrile (Table 2, entry 15). 1H
NMR (DMSO-d6, 500 Hz): δ 4.50 (s, 1H, CH), 7.01-7.14 (m,
3H, Ar), 7.31-7.41 (m, 5H, NH2 & Ar), 7.63-6.69 (m, 1H, Ar),
7.87 (dd, J = 7.9, 1.2 Hz, 1H, Ar) ppm; 13C NMR (DMSO-d6,
(DMSO-d6, 500 Hz): δ 4.61 (s, 1H, CH), 6.26 (d, J = 3.0 Hz,
1H, Ar), 6.32-6.39 (m, 1H, Ar), 7.42-7.50 (m, 5H, NH2 & Ar),
7.52 (s, 1H, Ar), 7.69 (t, J = 7.5 Hz, 1H, Ar), 7.85 (d, J = 7.7
Hz, 1H, Ar) ppm; 13C NMR (DMSO-d6, 125 Hz): δ 30.6, 55.3,
101.5, 106.4, 110.6, 112.8, 116.6, 118.9, 122.3, 124.6, 133.0,
547

Shaterian & Oveisi
142.3, 144.5, 152.1, 153.8, 154.1, 158.7, 159.3 ppm; IR (KBr,
°C. This implies that evaporation of the dehydration product,
3-hydroxyepropyl acetamide or its decomposition products
occurs at this temperature.
Conductivity of the liquid at room temperature is 0.123 ms
cm-1. The ionic conductivity depends largely on the
temperature and rises exponentially as the temperature
increases. This can be ascribed to the fast ion mobilities at
elevated temperatures.
Electrochemical stability of the ionic liquid is important
when redox reactions take place in such a medium. The
electrochemical stability was inspected by the cyclic
voltammetry. Redox stability of the ionic liquid must be
imposed by the reduction potential of the ammonium cation
and oxidation potential of the acetate anion. The cyclic
voltammetry indicates a useful stability range of 0.1-1.28 V.
The ionic liquid showed weak basic character, pH = 7.14.
Some common physical characteristics of the ionic liquid have
been tabulated in Table 1.
cm-1): 3368, 3282, 3169, 2201, 1704, 1672, 1604, 1376, 1268,
1171, 1111, 1056, 957, 757; MS (EI, 70 eV) m/z (%) = 317
(M+, 0.2), 306 (60), 278 (100), 239 (54), 158 (41), 121 (67),
92 (13), 63 (11). Anal. Calcd. for C18H11N3O3: C, 68.14; H,
3.49; N, 13.24%. Found: C, 68.20; H, 3.54; N, 13.35%.
2-Amino-4-(2,5-dimethoxyphenyl)-5-oxo-4,5-dihydro-
pyrano[3,2-c]chromene-3-carbonitrile (Table 2, entry 18).
1H NMR (DMSO-d6, 500 Hz): δ 3.63 (s, 3H, CH3), 3.64 (s,
3H, CH3), 4.64 (s, 1H, CH), 6.66 (d, J = 2.3 Hz, 1H, Ar), 6.75-
6.79 (m, 1H, Ar), 6.90 (d, J = 8.8 Hz, 1H, Ar), 7.25 (s, 2H,
NH2), 7.41-7.49 (m, 2H, Ar), 7.67 (t, J = 7.7 Hz, 1H, Ar), 7.89
(d, J = 7.7 Hz, 1H, Ar) ppm; 13C NMR (DMSO-d6, 125 Hz): δ
32.6, 55.2, 56.4, 56.8, 103.1, 112.2, 112.9, 113.1, 115.7,
116.4, 119.2, 122.2, 124.5, 131.9, 132.6, 151.5, 152.0, 153.1,
153.9, 158.5, 159.4 ppm; IR (KBr, cm-1): 3403, 3322, 3192,
2195, 1708, 1672, 1605, 1501, 1380, 1224, 1054, 959, 620;
MS (EI, 70 eV) m/z (%) = 376 (M+, 23), 361 (14), 345 (42),
279 (100), 239 (26), 215 (13), 121 (24). Anal. Calcd. for
C21H16N2O5: C, 67.82; H, 4.28; N, 7.44%. Found: C, 67.92; H,
4.36; N, 7.55%.
Both 1H NMR and FT-IR spectra indicate simple salt
structure of the liquid. Thus, in IR spectrum, the broad band at
3700-2300 cm-1 range implies typical ammonium structure.
The carbonyl stretching and N-H plane bonding vibrations are
observed as a combined band centered around 1628 cm-1. In
1H NMR spectra, the integral of the broad singlet in the 4.24-
4.82 ppm range represents four protons belonging to the sum
of ammonium and OH protons. When the spectrum was
determined in D2O as the solvent, these four protons having
hydrogen bonding character disappeared. In 13C NMR spectra,
the carbon atom of the acetate group exhibited a singlet at
180.5 ppm.
To optimize the amount of the catalyst, the reaction of
benzaldehyde (3 equiv.), malononitrile (3 equiv.), and 4-
hydroxycoumarin (3 equiv.) under grinding conditions was
selected as a model reaction at room temperature. The best
result was obtained by causing the reaction using 6 drops (0.12
g) of 3-hydroxypropanaminium acetate HPAA at room
temperature.
RESULTS AND DISCUSSION
The reaction of 3-propanolamine with acetic acid is highly
exothermic, and efficient cooling is essential throughout the
reaction. A simple acid-base reaction occurred and formed
ionic liquid, i.e. acetate salt of 3-propanolamine (Scheme 2).
Dropwise addition of acetic acid to 3-propanolamine under
continuous stirring at 0 °C, gives a viscous clear liquid which
remains non-frozen when stored in a deep-freeze compartment
of a refrigerator (-20 °C) for over 6 months. The liquid freezes
at -88 °C, as estimated from the DSC curve. Otherwise,
vigorous heat evolution may result in following dehydration of
the salt to give the corresponding amide. Dehydration of the
liquid salt commences around 104.67 °C, as estimated from
the TGA curve. The TGA shows 95.7% of mass loss at 226.86
O
EtOH
O oC
HO-CH2-CH2-CH2-NH2
+
CH3CO2H
HO-CH2-CH2-CH2-NH3
O
C CH3
Scheme 2. Preparation of task-specific ionic liquid, 3-hydroxypropanaminium acetate (HPAA)
548

A Simple Green Approach to the Synthesis of
Table 1. Some Common Physical Characteristics of the Ionic Liquid, 3-Hydroxypropanaminium Acetate (HPAA)
Density
Refractive index
conductivity
Decomposition Temperature
Freezing point
pH
1.205 g cm-3 at (25 °C)
1.4705 at (25 °C)
0.123 ms cm-1 at (25 °C)
226.86 °C by (TGA)
-88 °C by (DSC)
7.14 at 25 °C, concentration: 0.2 M in water
0.1-1.28 V
Electrochemical stability
Table 2. Synthesis of 2-Amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitrile Derivatives in the
Presence of HPAA
Entry
Aldehyde(s)
Time (min)/Yield (%)a
M.p. (°C)/(M.p.)Lit
1
2
Benzaldehyde
2-Chlorobenzaldehyde
4/91
7/88
245-246/245-24740
263-264/266-26848
3
3-Chlorobenzaldehyde
5/87
243-244/247-24849
4
5
6
4-Chlorobenzaldehyde
3-Nitrobenzaldehyde
4-Nitrobenzaldehyde
5/90
6/90
4/90
263-264/263-26531
261-262/262-26431
251-252/250-25240
7
4-Fluorobenzaldehyde
4-Hydroxybenzaldehyde
4-Methylbenzaldehyde
4-Methoxybenzaldehyde
4/90
9/92
6/90
5/91
263-264/260-26248
259-260/261-26249
258-259/254-25531
229-230/226-22850
8
9
10
11
12
2,3-Dichlorobenzaldehyde
2,4-Dichlorobenzaldehyde
4/78
5/89
282-283/280-28231
255-256/257-25931
182-185/185-18852
187-188b
13
14
cinnamaldehyde
3-Phenylpropanal
5/88
5/89
15
16
17
3-Fluorobenzaldehyde
2-Methylbenzaldehyde
Pyridine-2-carboxaldehyde
5/88
6/91
5/70
243-244b
264-265b
246-247b
18
2,5-Dimethoxybenzaldehyde
4/91
247-248b
aYields refer to the isolated pure products. All of the desired product(s) were characterized by comparison of
their physical and spectroscopic data with those of known compounds [31,48-50,52]. bThe spectral patterns of
the new products showed similar peaks and fragmentations according to analogous compounds which reported
in the literature.
549

Shaterian & Oveisi
CN
NH
Using these optimized reaction conditions, the scope and
CN
CN
HPAA
O
HPAA
HPAA
CHO
R
+
R
efficiency of the reactions were explored for the synthesis of a
wide variety of 2-amino-5-oxo-4,5-dihydropyrano[3,2-c]
chromene-3-carbonitriles using various aldehydes, 4-
hydroxycoumarin and malononitrile at room temperature. The
results are summarized in Table 2.
As shown in Table 2, the direct three-component reactions
worked well with cinnamaldehyde (entry 13), aliphatic
aldehydes (entry 14), heterocyclic 2-pyridinecarbaldehyde
(entry 17) and a variety of aryl aldehydes including the ones
carrying electron-withdrawing and -donating groups such as
OMe, OH, Cl, F and NO2. The desired compounds were
obtained in good to high yields. Also, we prepared 5 new
analogues of this class of compounds (entries 14-18). In the
case of aliphatic aldehydes such as n-heptaldehyde and n-
octaldehyde, the reactions were not completed after 24 h and
the desired products were obtained in low yields.
The suggested mechanism for the HEAA-catalyzed
transformations is shown in Scheme 3. As reported in the
literature [47], the Knoevenagel coupling of aldehydes with
malononitrile gives intermediate (I) and 3-hydroxypropan-
aminium acetate (HPAA) with weak basic character (Table 1,
pH = 7.14) acting as a catalyst. Then, the subsequent 1,4-
conjugate addition of 4-hydroxycoumarin to the intermediate
(I) followed by cyclization, affords the corresponding products
[51,52].
O
N
(I)
OH
N
O
CN
R
CN
H
O
O
HPAA
Products
R
H
O
O
O
Scheme 3. The suggested mechanism for preparation of 2-
amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-
3-carbonitrile derivatives
pressure, which promotes the association of the reactants in a
solvent cavity during the activation process and shows an
acceleration of the multi-component reactions (MCRs) in
comparison to the conventional solvents [40].
The reusability of the catalyst was tested in the synthesis of
2-amino-5-oxo-4-phenyl-4,5-dihydropyrano[3,2-c]chromene-
3-carbonitrile, as shown in Fig. 1. The catalyst was recovered
after each run (Section 2.3), and used for checking its activity
in the subsequent run. The catalyst was tested for 4 runs. It
was revealed that the catalyst displayed very good reusability.
In addition, the difference between the FT-IR spectrum of the
reused task-specific ionic liquid compared with the newly
synthesized ionic liquid, was so subtle, that confirmed no
change in the structure of the catalyst.
Ionic liquid (HPAA) is a weak basic catalyst and also plays
a solvent role. The HPAA effects as a solvent can be explained
in terms of solvophobic interactions that generate an internal
Table 3. Comparison Results of 3-Hydroxypropanaminium Acetate (HPAA) with other Catalysts Reported
in the Literature
Entry
Conditions
Time (min)/Yield (%)
1
2
HPAA (0.12 g), r.t.
4-9 min/70-92; present work
4 h/81-95
DAHP (10 mol%), H2O/EtOH (1:1), r.t.
(S)-Proline (10 mol%), H2O/EtOH (1:1), Reflux
H6[P2W18O62].18H2O (1 mol%), H2O: EtOH (1:1), Reflux
TBAB (10 mol%), H2O, Reflux
TBAB (10 mol%), Solvent-free, 120 °C
KF-Al2O3 (0.125 g), EtOH, 80 °C
Piperidine (0.5 ml), EtOH, ꢀ
3 h/72-88
3
4
30-85/86-90
45-60/84-93
40/75-89
4-7 h/80-90
30/70-90
5
6
7
TEBA (0.07 g), H2O, 90 °C
7-18 h/85-96
550

A Simple Green Approach to the Synthesis of
To demonstrate the effectiveness of the present work in
11 (2009) 956.
comparison with the previously reported results, we compared
the results of diammonium hydrogen phosphate and (S)-
proline [29], triethylbenzylammonium chloride [45], KF-
Al2O3 [46], piperidine [47], H6[P2W18O62] 18H2O [48] and
tetrabutylammonium bromide [49] in the synthesis of 2-
amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbo-
nitriles derivatives. As shown in Table 3, HPAA was found to
be an effective catalyst with respect to reaction time, yield,
and the resulting products.
[6]
[7]
D. Zhao, M. Wu, Y. Kou, E. Min, Catal. Today 74
(2002) 157.
W. Lu, A.G. Fadaev, B. Qu, E. Smela, B.R. Mattes, J.
Ding, G.M. Spinks, J. Mazurkiewicz, D. Zhou, G.G.
Wallace, D.R. MacFarlane, S.A. Forsyth, M. Forsyth,
Science 297 (2002) 983.
H. Olivier-Bourbigou, L. Magna, D. Morvan, Appl.
Catal. A-Gen. 373 (2010) 1.
P. Wasserscheid, W. Keim, Angew. Chem., Int. Ed. 39
(2000) 3772.
[8]
[9]
CONCLUSIONS
[10] J. Dupont, R.F. Souza, P.A.Z. Suarez, Chem. Rev. 102
(2002) 3667.
In summary, the new ionic liquid exhibited a low melting
temperature (-88 °C) which seems to be promising for use in
low temperature reactions. In addition, showing
electrochemical stability (0.1-1.28 V) and being obtainable
from commercially available low-cost chemicals, this ionic
liquid is expected to be useful as solvent for various reactions.
Moreover, an efficient protocol for the one-pot preparation of
2-amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbo-
nitriles from the three-component condensation reaction of 4-
hydroxycoumarin, aldehydes and malononitrile using a room
temperature task-specific ionic liquid, 3-hydroxypropan-
aminium acetate (HPAA) as a reusable catalyst under grinding
conditions was described.
[11] J.S. Wilkes, Green Chem. 4 (2002) 73.
[12] P. Wasserscheid, T. Welton, Ionic Liquids in
Synthesis, Wiley-VCH, Weinheim, Germany, 2003.
[13] D. Fang, Q.-R. Shi, J. Cheng, K. Gong, Z.-L. Liu, Appl.
Catal. A-Gen. 345 (2008) 158.
[14] A. Chrobok, S. Baj, W. Pudło, A. Jarzebski, Appl.
Catal. A-Gen. 366 (2009) 22.
[15] S. Luo, X. Mi, L. Zhang, S. Liu, H. Xu, J.-P. Cheng,
Angew. Chem., Int. Ed. 45 (2006) 3093.
[16] K. Fukumoto, M. Yoshizawa, H. Ohno, J. Am. Chem.
Soc. 127 (2005) 2398.
[17] Q. Yao, Y. Zhang, Angew. Chem., Int. Ed. 42 (2003)
3395.
[18] G. Song, Y. Cai, Y. Peng, J. Comb. Chem. 7 (2005)
561.
[19] J.-C. Xiao, B. Twamley, J.M. Shreeve, Org. Lett. 6
(2004) 3845.
[20] J.D. Holbrey, W.M. Reichert, I. Tkatchenko, E.
Bouajila, O. Walter, I. Tommasi, R.D. Rogers, Chem.
Commun. (2003) 28.
ACKNOWLEDGEMENTS
The authors are thankful to the Sistan and Baluchestan
University Research Council for the partial support of this
work.
REFERENCES
[21] A.K. Bose, S. Pednekar, S.N. Ganguly, G.
Chakrabortyb, M.S. Manhas, Tetrahedron Lett. 45
(2004) 8351.
[22] F. Toda, K. Tanaka, A. Sekikawa, J. Chem. Soc.,
Chem. Commun. (1987) 279.
[23] K. Tanaka, Solvent-Free Organic Synthesis, Wiley-
VCH, Weinheim, 2003.
[24] G.R. Green, J.M. Evans, A.K. Vong, in: A.R. Katritzky,
C.W. Rees, E.F. Scriven (Eds.), In Comprehensive
Heterocyclic Chemistry II, 5, Pergamon Press, Oxford,
[1]
[2]
[3]
A. Domling, Chem. Rev. 106 (2006) 17.
I. Ugi, Adv. Synth. Catal. 339 (1997) 499.
N.K. Terret, M. Gardener, D.W. Gordon, R.J.
Kobylecki, J. Steele, Tetrahedron 51 (1995) 8135.
A. Domling, I. Ugi, Angew. Chem., Int. Ed. 39 (2000)
3168.
[4]
[5]
A. Shaabani, R. Ghadari, S. Ghasemi, M. Pedarpour,
A.H. Rezayan, A. Sarvary, S.W. Ng, J. Comb. Chem.
551

Shaterian & Oveisi
1995, p. 469.
[39] Y.-M. Ren, C. Cai, Catal. Commun. 9 (2008) 1017.
[40] A. Shaabani, S. Samadi, Z. Badri, A. Rahmati, Catal.
Lett. 104 (2005) 39.
[25] W.O. Foye, Principi Di Chemica Frmaceutica, Piccin,
Padova, Italy, 1991.
[26] A. Burgard, H.-J. Lang, U. Gerlach, Tetrahedron 55
(1999) 7555.
[41] H.R. Shaterian, A. Hosseinian, M. Ghashang,
Tetrahedron Lett. 49 (2008) 5804.
[27] J.M. Evans, C.S. Fake, T.C. Hamilton, R.H. Poyser,
G.A. Showell, J. Med. Chem. 27 (1984) 1127.
[28] J.M. Evans, C.S. Fake, T.C. Hamilton, R.H. Poyser,
E.A. Watts, J. Med. Chem. 26 (1983) 1582.
[29] D. Arnesto, W.M. Horspool, N. Martin, A. Ramos, C.
Seaone, J. Org. Chem. 54 (1989) 3069.
[30] R.M. Shaker, Pharmazie 51 (1996) 148.
[31] S. Abdolmohammadi, S. Balalaie, Tetrahedron Lett. 48
(2007) 3299.
[32] M. Kidwai, S. Saxena, Synth. Commun. 36 (2006)
2737.
[33] C. Wiener, C.H. Schroeder, B.D. West, K.P. Link, J.
Org. Chem. 27 (1962) 3086.
[42] H.R. Shaterian, A. Hosseinian, H. Yarahmadi, M.
Ghashang, Lett. Org. Chem. 5 (2008) 290.
[43] H.R. Shaterian, A. Hosseinian, M. Ghashang, Synth.
Commun. 38 (2008) 3766.
[44] H.R. Shaterian, A. Hosseinian, M. Ghashang, Can. J.
Chem. 86 (2008) 376.
[45] H.R. Shaterian, A. Hosseinian, M. Ghashang,
ARKIVOC ii (2009) 59.
[46] H.R. Shaterian, A. Hosseinian, M. Ghashang, Synth.
Commun. 39 (2009) 2560.
[47] N. Bicak, J. Mol. Liq. 116 (2005) 15.
[48] S. Da-Qing, W. Jing, Z. Qi-Ya, W. Xiang-Shan, Chin.
J. Org. Chem. 26 (2006) 643.
[34] B.H. Rizkalla, A.D. Broom, J. Org. Chem. 37 (1972)
3980.
[35] A.D. Broom, J.L. Shim, G.L. Anderson, J. Org. Chem.
41 (1976) 1095.
[49] W. Xiang-Shan, Z. Zhao-Sen, S. Da-Qing, W. Xian-
Yong, Z. Zhi-Min, Chin. J. Org. Chem. 25 (2005) 1138.
[50] A.M. El-Agrody, M.S.A. El-Latif, A.H. Fakery, A.H.
Bedair, J. Chem. Res (S) (2000) 26.
[36] V.K. Ahluwalia, R. Kumar, A. Khurana, R. Bhatla,
Tetrahedron 46 (1990) 3953.
[37] E.V. Stoyanov, I.C. Ivanov, D. Heber, Molecules 5
(2000) 19.
[38] P. Srivastava, A.S. Saxena, V.J. Ram, Synthesis (2000)
541.
[51] M.M. Heravi, B. Alimadadi-Jani, F. Derikvand, F.F.
Bamoharram, H.A. Oskooie, Catal. Commu. 10 (2008)
272.
[52] J.M. Khurana, S. Kumar, Tetrahedron lett. 50 (2009)
4125.
552