Straightforward and solvent-free synthesis of 2-amino-4H-chromenes in the presence of a choline-based magnetic ionic liquid as catalyst

Article abstract of DOI:10.1134/S1070363216050327

Choline tetrachloroferrate with a magnetic response property is applied in multicomponent one-pot synthesis of 2-amino-4H-chromenes as effective catalyst. The catalyst is characterized by the UV–Vis and Raman spectroscopies and by the electrospray ionizat

Full text of DOI:10.1134/S1070363216050327

ISSN 1070-3632, Russian Journal of General Chemistry, 2016, Vol. 86, No. 5, pp. 1177–1181. © Pleiades Publishing, Ltd., 2016.
Straightforward and Solvent-Free Synthesis
of 2-Amino-4H-chromenes in the Presence
of a Choline-Based Magnetic Ionic Liquid as Catalyst1
M. Khodajooa, S. Sayyahia*, and S. J. Saghanezhadb
a Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
*e-mail: sayyahi.soheil@gmail.com
b ACECR-Production Technology Research Institute, Ahvaz, Iran
Received December 27, 2015
Abstract—Choline tetrachloroferrate with a magnetic response property is applied in multicomponent one-pot
synthesis of 2-amino-4H-chromenes as effective catalyst. The catalyst is characterized by the UV–Vis and
Raman spectroscopies and by the electrospray ionization mass spectrometry.
Keywords: magnetic ionic liquid, 2-amino-4H-chromene derivatives, multicomponent reactions, choline
chloride, choline tetrachloroferrate
DOI: 10.1134/S1070363216050327
INTRODUCTION
Magnetic ionic liquids combine general properties of
room-temperature ionic liquids with the properties
associated with incorporation of a metal ion into their
structure, such as strong response to an external
magnetic field and photophysical/optical or catalytic
properties [12].
The sequencing of multicomponent reactions
(MCRs) and subsequent cyclization reactions provide
powerful tools for the synthesis of biologically active
complex molecules and natural products, which are the
very important compounds for many chemical areas,
including medicinal and pharmaceutical chemistry [1–3].
As part of our ongoing studies of green synthetic
approaches [13–16] and in continuation of our
previous study on the application of MILs in multi-
component reactions [17], we study here the catalytic
behavior of choline tetrachloroferrate in the synthesis
of 2-amino-4H-chromenes.
2-Amino-4H-chromenes are a class of privileged
heterocycles that show a variety of activities, such as
antibacterial, mutagenic, antiviral, antitumoral, anti-
coagulant, and antianaphylactic activity. These
compounds are also applied in cosmetics and pigments
and are potential biodegradable agrochemicals [4–6].
Commonly, they are synthesized by three-component
condensation of aldehyde, malononitrile, and activated
phenol under catalytic conditions. However, most of
the reported methods have such drawbacks as low
yield, long reaction time, harsh reaction conditions,
hard work-up procedure, complex reaction pathway,
and proceed in the presence of expensive or toxic
catalysts [7–9].
RESULTS AND DISCUSSION
Choline chloride, (2-hydroxyethyl) trimethylammo-
niumchloride, is commercially available, cheap, bio-
Scheme 1. Preparation of choline chloride-based paramagnetic
ionic liquid.
(CH3)3N+
OH
Cl−
Methanol,
room temperature,
24 h
Since the first synthesis and application of a
magnetic ionic liquid (MIL) [10, 11], a wide variety of
interests has been focused on this class of compounds.
.
FeCl3 6H2O
(CH3)3N+
FeCl4−
OH
1 The text was submitted by the authors in English.
1177

1178
KHODAJOO et al.
λ, nm
Fig. 2. Visible absorption spectrum of choline [FeCl4].
× 102
(a)
Fig. 1. Response of choline [FeCl4] to an external magnetic
field.
Intensity, rel. units
m/z
× 103
(b)
ν, cm–1
m/z
Fig. 4. (a) Positive and (b) negative ion spectra of choline
[FeCl4]–.
Fig. 3. Raman spectrum of the MIL.
degradable, non-toxic, and non-explosive quaternary
ammonium salt. It can be synthesized from fossil
reserves in large-scale quantities through the process
with a very high atom economy [18, 19].
the visible region, which can be attributed to the
[FeCl4] anion (Fig. 2).
Raman spectra of ammonium tetrachloroferrate
salts have strong peak attributable to stretch vibrations
of the totally symmetric Fe–Cl bond at approximately
330 cm–1 and peaks attributable to the (CH3)3N+CH2·
CH2OH cation in the regions 1400–1600 and 2800–
3050 cm–1 (Fig. 3).
Choline tetrachloroferrate is prepared by mixing
choline chloride and iron(III) chloride hexahydrate
(molar ratio 1 : 1.2) under ambient conditions (Scheme 1).
The magnetic properties of the ionic liquid were
screened at the magnetic field strength of 1 T supplied
with an NdFeB magnet. As seen, the properties of
choline [FeCl4] can be manipulated through the
application of a strong magnetic field (Fig. 1).
The above results were also confirmed by data on
the electrospray ionization mass spectrometry: peaks at
m/e = 104.10 and 197.80 in the ESI-MS spectra are
due to (CH3)3N+CH2CH2OH and FeCl4–, respectively
(Fig. 4).
The paramagnetic ionic liquid was characterized by
several methods. The absorption spectrum has bands in
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 5 2016

STRAIGHTFORWARD AND SOLVENT-FREE SYNTHESIS
Table 1. Screening of the reaction conditionsa
1179
We found that choline [FeCl4] has a significant
catalytic performance in multicomponent synthesis of
2-amino-4H-chromenes. The condensation of p-nitro benz-
aldehyde, malononitrile, and β-naphthol (1 : 1 : 1 mmol)
was used as a model reaction in order to optimize the
reaction conditions. For this purpose, the reaction was
carried out at varied amounts of MIL (0.05, 0.1, and
0.2 mmol) and different temperatures (room
temperature, 40, and 60°C). In the absence of the
catalyst, trace amounts of the product were detected.
The best result was obtained when the reaction was
carried out with 20 mol % of choline [FeCl4] at 60°C
to give 1H-naphtho[2,1-b]pyran-2-carbonitrile,3-amino-
1-(4-nitrophenyl) (Table 1, run no. 4). Fortunately, the
desired chromenes in high yield are obtained by this
procedure in the presence of different substituted
aromatic benzaldehydes and no by-products is formed
(Table 2).
Run Catalyst,
Temperature,
°C
Time,
min
Yieldb,
no.
mol %
%
Trace
>20
65
1
–
60
120
30
30
30
30
30
2
5
60
3
10
20
20
20
60
4
60
40
94
5
55
6
Room temperature
35
a
p-Nitro benzaldehyde (1 mmol), malononitrile (1 mmol), and β-
naphthol (1 mmol). b Isolated yield.
naphthol is deprotonated with tetrachloroferrate, the
subsequent Michael addition occurs. The final step,
following enol formation, is the intramolecular
cyclization with the replacement of hydrogen to give
the product.
A
probable mechanistic rationale portraying
sequence of events for this coupling reaction is
postulated in Scheme 2. In the first step, the carbonyl
group is activated via the positive part of MIL,
facilitating the nucleophilic attack of malononitrile, by
the Knoevenagel condensation mechanism. After β-
EXPERIMENTAL
All compounds were synthesized from commercial
sources and used without further purification. Melting
Table 2. Synthesis of 2-amino-4H-chromene derivatives in the presence of MIL as catalyst under solvent-free conditions
CN
Ar CHO
NC
CN
Ar
NH2
1
2
Choline [FeCl4]−
60oC
OH
O
3
4a−4i
Product a
4a
Ar
Time, min
Yieldb, %
mp, °C
277–279 (280)
References
[4]
C6H5
40
30
35
35
30
40
35
70
60
96
94
87
96
95
96
95
86
92
4b
4-NO2-C6H4
4-Cl-C6H4
185–186 (188–189)
205–206 (206–208)
240–243 (241–243)
182–183 (182–183)
269–271 (270–271)
235–236 (232–235)
259–260 (262–263)
258–261 (259–261)
[4]
4c
[9]
4d
4-Br-C6H4
[9]
4e
4-MeO-C6H4
4-Me-C6H4
3-NO2-C6H4
3-MeO-C6H4
2-Cl-C6H4
[4]
4f
[20]
[9]
4g
4h
[21]
[9]
4i
a
The products are known and were identified by comparison of their melting points and spectral data with those reported in the literature.
Yield is given for isolated not-purified products.
b
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 5 2016

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KHODAJOO et al.
Scheme 2. The proposed mechanism of the multicomponent reaction in the presence of choline [FeCl4] as catalyst.
Ar
CN
C N
5
4
6
FeCl4−
2
O
H
3
(CH3)3N+CH2CH2OH
FeCl4−
1
+
O
NC
CN
CN
Ar
H
7
N−
Ar
HFeCl4−
9
H
O
8
points are given uncorrected. The visible absorption
spectra of the samples (0.1 M acetonitrile solutions)
were recorded on a Jenway Genova Plus UV–Vis
spectrometer in the region 500–1000 nm. The Raman
spectra were measured on an Almega Thermo Nicolet
Dispersive Raman spectrometer at the wavelength
532 nm delivered by a Nd:YLF laser. The electrospray
ionization-mass (ESI-MS) spectrometry was done on
an Agilent 6410 Triple Quadrupole LC/MS mass
spectrometer.
spectrometry. After successful characterization, the
catalytic activity of MIL was evaluated in the one-pot
preparation of 2-amino-4H-chromenes. Advantages of
using this catalyst are simple work-up procedure, eco-
friendly reaction conditions, short reaction time, and
high yield of the products.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the financial
support from the Mahshahr Branch, Islamic Azad
University, Iran.
General procedure for the synthesis 2-amino-
4H-chromenes. Into a test tube, aldehyde (1 mmol), β-
naphthol (1 mmol), malononitrile (1 mmol), and
choline tetrachloroferrate (0.2 mmol) were introduced
and the resulting solution was heated on a thermostatic
oil bath to 60°C for the required time (Table 2). The
mixture was cooled to room temperature, then 10 mL
of water was added to it, and the mixture was stirred
for 5 min. The aqueous layer was decanted and dried
under vacuum in order to recover the catalyst. The
crude product was purified by recrystallization from
hot ethanol.
REFERENCES
1. Touré, B.B., and Hall, D.G., Chem. Rev., 2009,
vol. 109, p. 4439. DOI: 10.1021/cr800296p.
2. Slobbe, P., Ruijter, E., and Orru, R.V.A., Med. Chem.
Comm., 2012, vol. 3, p. 1189. DOI: 10.1039/c2md20089a.
3. Cioc, R.C., Ruijter, E., and Orru, R.V.A., Green Chem.,
2014, vol. 16, p. 2958. DOI: 10.1039/c4gc00013g.
4. Heravi, M.M., Bakhtiari, K, Zadsirjan V., Bamohar-
ram, F.F., and Heravi, O.M., Bioorg. Med. Chem. Lett.,
2007,
vol.
17,
p.
4262.
DOI:
10.1016/
j.bmcl.2007.05.023.
CONCLUSIONS
5. Zhang, G., Zhang, Y., Yan, J., Chen, R., Wang, S., Ma, Y.,
and Wang, R., J. Org. Chem., 2012, vol.77, p. 878.
DOI: 10.1021/jo202020m.
6. Elinson, M.N., Dorofeev, A.S., Miloserdov, F.M.,
Ilovaisky, A.I., Feducovich, S.K., Belyakov, P.A., and
In conclusion, choline tetrachloroferrate magnetic
ionic liquid was prepared and its properties were
determined by the UV–visible and Raman spectro-
scopies and by the electrospray ionization mass
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 5 2016

STRAIGHTFORWARD AND SOLVENT-FREE SYNTHESIS
1181
Nikishin, G.I., Adv. Synth. Catal., 2008, vol. 350,
p. 591. DOI: 10.1002/adsc.200700493.
14. Kiasat, A.R. and Sayyahi, S., Catal. Commun., 2010,
vol. 11, p. 484. DOI: 10.1016/j.catcom.2009.12.005.
15. Kiasat, A.R. and Sayyahi, S., Mol. Divers., 2010,
vol. 14, p. 155. DOI: 10.1007/s11030-009-9191-3.
16. Sayyahi, S., Rezaee, H.M, Khalfabadi, F.S., and
Gorjizadeh, M., J. Chem. Res., 2012, vol. 36, p. 396.
DOI: 10.3184/174751912x13371750612188.
17. Sayyahi, S., Azin, A., and Saghanezhad, S.J., J. Mol.
Liq., 2014, vol. 198, p. 30. DOI: 10.1016/
j.molliq.2014.07.003.
18. Sousa, A.M.M., Souza, H.K.S., Latona, N., Liu, C.K.,
Goncalves, M.P., and Liu, L., Carbohyd. Polym., 2014,
vol. 111, p. 206. DOI: 10.1016/j.carbpol.2014.04.019.
19. Zhang, Q., De Oliveira Vigier, K., Royer, S., and
Jerome, F., Chem. Soc. Rev. 2012, vol. 41, p. 7108.
DOI: 10.1039/c2cs35178a.
20. Gong, K., Wang, H.L., Fang, D., and Liu, Z.L., Catal.
Commun., 2008, vol. 9, p. 650. DOI: 10.1016/
j.catcom.2007.07.010.
7. Safari, J. and Javadian, L., Ultrason. Sonochem., 2015,
vol. 22, p. 341. DOI: 10.1016/j.ultsonch.2014.02.002.
8. Magar, R.L., Thorat, P.B., Jadhav, V.B., Tekale, S.U.,
Dake, S.A., Patil, B.R., and Pawar R.P., J. Mol. Catal.
A: Chem., 2013, vols. 374–375, p. 118. DOI: 10.1016/
j.molcata.2013.03.022.
9. Naimi-Jamal, M.R., Mashkouri, S., and Sharifi, A.,
Mol. Divers., 2010, vol. 14, p. 473. DOI: 10.1007/
s11030-010-9246-5.
10. Sitze, M.S., Schreiter, E.R., Patterson, E.V., and
Freeman, R.G., Inorg. Chem., 2001, vol. 40, p. 2298.
DOI: 10.1021/ic001042r.
11. Hayashi, S. and Hamaguchi, H.O., Chem. Lett., 2004,
vol. 33, p. 1590. DOI: 10.1246/cl.2004.1590.
12. Santos, E., Albo, J., and Irabien, A., RSC Adv., 2014,
vol. 4, p. 40008. DOI: 10.1039/c4ra05156d.
21. Wang, X.S., Yang, G.S., and Zhao, G., Tetrahedron-
Asymmetr., 2008, vol. 19, p. 709. DOI: 10.1016/
j.tetasy.2008.02.018.
13. Sayyahi, S., Moonesi, S., and Fallah-Mehrjardi, M.,
Phosphorus Sulfur, 2014 vol. 189, p. 1718. DOI:
10.1080/10426507.2014.887078.
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