Nano-Fe3O4?walnut shell/Cu(ii) as a highly effective environmentally friendly catalyst for the one-potpseudothree-component synthesis of 1,3-oxazine derivatives under solvent-free conditions

Article abstract of DOI:10.1039/d0ra04282j

Fe₃O₄?walnut shell/Cu(ii) as an eco-friendly bio-based magnetic nano-catalyst was prepared by adding CuCl₂to Fe₃O₄?walnut shell in alkaline medium. A series of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines were synthesized by the one-potpseudothree-component reaction of β-naphthol, formaldehyde and various amines using nano-Fe₃O₄?walnut shell/Cu(ii) at 60 °C under solvent-free conditions. The catalyst was removed from the reaction mixture by an external magnet and was reusable several times without any considerable loss of its activity. This protocol has several advantages such as excellent yields, short reaction times, clean and convenient procedure, easy work-up and use of an eco-friendly catalyst.

Full text of DOI:10.1039/d0ra04282j

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Nano-Fe3O4@walnut shell/Cu(II) as a highly
effective environmentally friendly catalyst for the
one-pot pseudo three-component synthesis of 1,3-
oxazine derivatives under solvent-free conditions†
Cite this: RSC Adv., 2020, 10, 31874
*
Arefeh Dehghani Tafti and Bi Bi Fatemeh Mirjalili
Fe3O4@walnut shell/Cu(II) as an eco-friendly bio-based magnetic nano-catalyst was prepared by adding CuCl2 to
Fe3O4@walnut shell in alkaline medium. A series of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines
were synthesized by the one-pot pseudo three-component reaction of b-naphthol, formaldehyde and
various amines using nano-Fe3O4@walnut shell/Cu(II) at 60 ꢀC under solvent-free conditions. The catalyst was
removed from the reaction mixture by an external magnet and was reusable several times without any
considerable loss of its activity. This protocol has several advantages such as excellent yields, short reaction
times, clean and convenient procedure, easy work-up and use of an eco-friendly catalyst.
Received 13th May 2020
Accepted 8th August 2020
DOI: 10.1039/d0ra04282j
rsc.li/rsc-advances
Biopolymers, especially cellulose and its derivatives, have some CCl3COOH.19 Other methods of synthesis of oxazines are aza-
unparalleled properties, which make them attractive alterna- acetalizations of aromatic aldehydes with 2-(N-substituted
tives for ordinary organic or inorganic supports for catalytic aminomethyl) phenols in the presence of an acid as catalyst20
applications.1 Cellulose is the most abundant natural material and electrooxidative cyclization of hydroxyamino compounds.21
in the world and it can play an important role as a biocompat-
However, some of these catalysts have limitations such as
ible, renewable resource and biodegradable polymer containing inefficient separation of the catalyst from reaction mixtures,
OH groups.2 Walnut shell is a natural, cheap, and readily unrecyclable and environmental limitations. Therefore, the
available source of cellulose. Fe3O4 nanoparticles are coated development of green and clean methodology for the prepara-
with various materials such as surfactants,3 polymers,4,5 silica,6 tion of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine
cellulose7 and carbon8 to form core–shell structures. Magnetic derivatives is still an interesting challenge.
nanoparticles as heterogeneous supports have many advan-
Herein, we wish to report the preparation of Fe3O4@nano-
tages such as high dispersion in reaction media and easy walnut shell/Cu(II) as a new and bio-based magnetic nanocatalyst
recovery by an external magnet.9 Cu(II) as a safe and ecofriendly and its using for one-pot synthesis of 1,3-oxazine derivatives via
cation is a good Lewis acid and can activate the carbonyl group condensation of b-naphthol, primary amine and formaldehyde.
for nucleophilic addition reactions.10
1,3-Oxazines moiety has gained great attention from many
organic and pharmaceutical chemists due to their broad range
of biological activities such as anticancer,11 anti-bacterial,12
anti-tumor13 and anti-Parkinson's disease.14
Results and discussion
The sequential step for the preparation of nano-Fe3O4@walnut
shell/Cu(II) has been shown in Scheme 2. At rst, nano-walnut
shell was prepared from walnut shell using the previously re-
ported method for preparation of nanocellulose.7 Then,
magnetic core–shell nanoparticles, nano-Fe3O4@walnut shell,
were obtained simply through in situ co-precipitation of ferric
and ferrous ions with ammonium hydroxide in an aqueous
solution containing nano-walnut shell.7 At the end, the nano-
Fe3O4@walnut shell served as a magnetic support for the
immobilization of Cu(II) by simple grinding with CuCl2$2H2O at
room temperature (Scheme 1). The characterization of nano-
Fe3O4@walnut shell/Cu(II), structure was performed by Fourier
transform infrared (FT-IR) spectroscopy, X-ray diffraction
(XRD), vibrating sample magnetometer (VSM), eld emission
Owing to the biological importance of benzo-fused 1,3-oxa-
zines, various methods have been developed for the synthesis of
these compounds. Some shown protocols for the synthesis of
various 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines
via a Mannich type condensation between a 2-naphthol, form-
aldehyde and a primary amine were reported. This protocol has
been catalyzed by KAl(SO4)2$12H2O (alum),15 ZrOCl2,16 poly-
ethylene glycol (PEG),17 thiamine hydrochloride (VB1)18 and
Department of Chemistry, College of Science, Yazd University, P.O. Box 89195-741,
Yazd, Iran. E-mail: fmirjalili@yazd.ac.ir; Fax: +983538210644; Tel: +983531232672
† Electronic supplementary information (ESI) available. See DOI:
10.1039/d0ra04282j
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Fig. 2 XRD patterns of the (a) Fe3O4 (b) nano-Fe3O4@walnut shell, (c)
nano-Fe3O4@walnut shell/Cu(II).
Scheme 1 Graphical representation preparation of nano-Fe3O4@-
walnut shell/Cu(II).
Fe3O4@walnut shell and nano-Fe3O4@walnut shell/Cu(II) shows
the additional weak diffraction peaks at 2q ¼ 39ꢀ and 54ꢀ in nano-
Fe3O4@walnut shell/Cu(II), which seems to be linked to Cu(II) on
the surface of nano-Fe3O4@walnut shell (Fig. 2(c)).
scanning electron microscopy (FESEM), energy-dispersive X-ray
spectroscopy (EDS), and thermo-gravimetric analysis (TGA).
Fig. 1 shows the FT-IR spectra of nano-walnut shell, nano-Fe3-
O4@walnut shell and nano-Fe3O4@walnut shell/Cu(II). The FT-IR
spectrum of nano-walnut shell (Fig. 1(a)), has shown a broad
band at 3323 cmꢁ1 which corresponds to the stretching vibrations
of OH groups. The absorption bands at 1029–1160 cmꢁ1 display
the stretching vibrations of the C–O bonds.
For nano-Fe3O4@walnut shell (Fig. 1(b)), in addition to the
walnut shell absorptions bands, stretching vibrations of Fe/O
groups at 584 and 622 cmꢁ1 are appeared which is indicated that
the magnetic Fe3O4 nano particles are coated by nano-walnut shell.
The FT-IR spectrum of nano-Fe3O4@walnut shell/Cu(II) (Fig. 1(c))
has shown a characteristic absorption band under 500 cmꢁ1 that
may be attributed to Cu–O band for Cu bonded to walnut shell.
The comparison between Fe3O4, nano-Fe3O4@walnut shell and
nano-Fe3O4@walnut shell/Cu(II), XRD patterns in a range of 10–80ꢀ
was shown in Fig. 2. In nano-Fe3O4@walnut shell XRD pattern, in
addition to all peaks of naked Fe3O4 (2q ¼ 30ꢀ, 35ꢀ, 43ꢀ, 53ꢀ, 57ꢀ,
63ꢀ, 71ꢀ and 73ꢀ), 2q ¼ 23ꢀ conrmed the existence of walnut shell
in its structure. The difference between XRD patterns of nano-
Fig. 3 represents the result of eld emission scanning elec-
tron microscopy (FESEM) of nano-Fe3O4@walnut shell/Cu(II) to
investigate its particle size and surface morphology. This image
indicates that Fe3O4@walnut shell/Cu(II) nanoparticles have
a quasi-spherical shape with an average size about 15 nm.
The magnetic properties of Fe3O4 and nano-Fe3O4@walnut
shell/Cu(II) were characterized at RT (300 K) by a vibrating
sample magnetometer (VSM) and their hysteresis curves are
presented in Fig. 4. According to this image, the zero coercivity
and remanence of the hysteresis loops of these magnetic
nanoparticles conrm superparamagnetic property of them at
room temperature. The amount of specic saturation magne-
tization (Ms) for Fe3O4 nanoparticles was about 47 emu gꢁ1
,
which decreased to 32 emu gꢁ1 aer coating the Fe3O4 with
walnut shell and to 12 emu gꢁ1 aer the immobilization of
Cu(II) on the surface of nano-Fe3O4@walnut shell. Despite this
signicant decrease, the saturated magnetization of these
magnetic nanoparticles is sufficient for magnetic separation.
Fig. 1 FT-IR spectra of (a) nano-walnut shell, (b) nano-Fe3O4@walnut
shell, (c) nano-Fe3O4@walnut shell/Cu(II).
Fig. 3 FESEM image of nano-Fe3O4@walnut shell/Cu(II).
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Fig. 4 Magnetization loops of (a) Fe3O4 (b) nano-Fe3O4@walnut shell,
(c) nano-Fe3O4@walnut shell/Cu(II).
Fig. 6 EDX patterns of nano-Fe3O4@walnut shell/Cu(II).
TGA-DTA analysis was performed to study thermal stability
of the nano-Fe3O4@walnut shell/Cu(II) in the temperature range
of 50–810 ꢀC (Fig. 5). The rst decrease of weight was assigned
to the catalyst moisture removal (endothermic effect at 50–
190 ꢀC, 8% weight loss). Subsequently, the main weight loss
step in the temperature ranges 200–360 ꢀC (34%) is attributed to
the decomposition of walnut shell. The char yield of the catalyst
in 810 ꢀC is 42.16%.
The model reaction was easier and gave the highest yield in
solvent-free condition. Using the optimal reaction conditions,
the scope and the versatility of this catalytic protocol were
explored for the synthesis of various 2-aryl/alkyl-2,3-dihydro-1H-
naphtho[1,2-e][1,3]oxazine (Table 2). The obtained results
indicate that the reactions can proceed well enough with
The existence of the expected elements in the structure of the
nano-Fe3O4@walnut shell/Cu(II) was approved by energy-dispersive
X-ray spectroscopy EDS (EDX) analysis (Fig. 6). The EDS results
clearly conrm the presence of Fe, O, Cu, C, Cl elements in the
catalyst. The weight percentages of Fe, O, Cu, C and Cl are 19.48,
34.60, 26.09, 19.22 and 0.62%, respectively.
Table 1 The reaction of b-naphthol, formaldehyde, and aniline in the
presence of nano-Fe3O4@walnut shell/Cu(II) under various conditionsa
The catalytic activity of nano-Fe3O4@walnut shell/Cu(II) as
a magnetically recyclable solid acid catalyst was investigated for
the synthesis of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]
oxazine using three-component reaction of 2-naphthol, form-
aldehyde, and primary amines.
Conditions
As a model reaction, the reaction between b-naphthol,
formaldehyde, and aniline was investigated under various
conditions (Table 1). As can be seen from Table 1, the highest
yield was achieved by using 0.08 g catalyst at 60 ꢀC under
solvent-free condition (Table 1, entry 3). Other solvents such as
H2O, CH2Cl2, EtOH, CH3CN, CHCl3 and MeOH gave the desired
products in low yields even aer elongated reaction times in the
same temperature (Table 1, entries 5–10).
Entry
Solvent/temp (ꢀC)/catalyst (g)
Time (min)
Yieldb (%)
1
2
3
4
5
6
7
8
—/r.t/catalyst (0.08)c
—/50/catalyst (0.08)c
—/60/catalyst (0.08)c
—/80/catalyst (0.08)c
H2O/60/catalyst (0.08)c
CH2Cl2/60/catalyst (0.08)c
EtOH/60/catalyst (0.08)c
CH3CN/60/catalyst (0.08)c
CHCl3/60/catalyst (0.08)c
MeOH/60/catalyst (0.08)c
—/60/catalyst (0.04)c
—/60/catalyst (0.06)c
—/60/catalyst (0.07)c
—/60/catalyst (0.09)c
—/60/catalyst (0.1)c
—/60/—
190
45
25
50
45
60
60
60
60
60
50
40
25
35
60
200
180
20
88
93
75
73
52
70
40
50
65
85
90
90
90
60
5
9
10
11
12
13
14
15
16
17
—/60/nano-Fe3O4@walnut shell
(0.08)
25
18
—/60/CuCl2 (0.08)c
180
55
a
b
c
The molar ratios are 1 : 2 : 3 is 1 : 2 : 1. Isolated yield. Nano-
Fe3O4@walnut shell/Cu(II).
Fig. 5 Thermal gravimetric analysis pattern of nano-Fe3O4@walnut
shell/Cu(II).
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Table 2 Synthesis of [1,3]oxazine derivatives in the presence of nano-Fe3O4@walnut shell/Cu(II) at 60 ꢀC under solvent-free conditiona
Entry
R
Product
Time (min)
Yieldb (%)
Mp (ꢀC) (ref.)
1
2
3
4
5
6
7
8
C6H5–
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
9a
9b
9c
11a
11b
11c
11d
25
15
25
15
10
25
30
15
10
15
25
30
25
40
30
25
30
25
25
35
93
92
90
89
93
90
88
85
90
90
89
92
92
85
87
88
84
87
82
85
45–47 (ref. 15)
87–89 (ref. 15)
44–46 (ref. 22)
100–103 (ref. 18)
116–119 (ref. 15)
123–125 (ref. 23)
70–73 (ref. 22)
75–77 (ref. 15)
232(d) (ref. 22)
248(d) (ref. 22)
177(d) (ref. 22)
98–100 (ref. 22)
170(d) (ref. 22)
59–62 (ref. 24)
67–69 (ref. 25)
75–76 (ref. 24)
57–60 (ref. 16)
107–109
4-Me–C6H4–
4-Et–C6H4–
4-Cl–C6H4–
4-Br–C6H4–
C6H5–CH2–
2-Cl–C6H4–CH2–
4-OMe–C6H4–
C6H5–CH2–CH2–
Cyclohexyl–
n-Hexyl–
2-Furyl–CH2–
n-Butyl–
C6H5–
4-Cl–C6H4–
C6H5–
C6H5–
9
10
11
12
13
14
15
16
17
18
19
20
4-Cl–C6H4–
4-OMe–C6H4–
4-Me–C6H4–
300(d) (ref. 16)
195–198 (ref. 16)
a
The amount ratio of of primary amine (1 mmol), formaldehyde (2 mmol), b-naphthol, phenol or a-naphthol (1 mmol) equal to 1 : 2 : 1. b Isolated
yield.
a relatively wide range of primary amines (aliphatic and activity (Fig. 7). Meanwhile, FT-IR spectra of recovered catalyst
aromatic) containing electron-donating and electron- were identical with the original catalyst spectra that indicating
withdrawing groups.
no considerable leaching of catalyst in reaction medium.
The structures of these products were characterized by
physical and spectroscopic data such as mp, FT-IR, 1H NMR,
and 13C NMR.
The separated nano-catalyst was reused in the mentioned
reaction ve times without considerable loss of its catalytic
Fig. 7 Reusability of catalyst in the reaction between formaldehyde, Scheme 2 Proposed mechanism for the synthesis of 1,3-oxazine
aniline, and b-naphthol.
derivatives.
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Table 3 Catalytic performances of nano-Fe3O4@walnut shell/Cu(II) versus some other catalysts for synthesis of 4a
Conditions
Entry
Solvent/temp (ꢀC)/catalyst
Time (min)
Yield (%) (ref.)
1
2
3
4
5
6
7
8
—/60/[bmim]HSO4
H2O/r.t/thiamin hydrochloride (VB1)
H2O/r.t/—
30
30
30–60
10
20
15
25
25
90 (ref. 26)
92 (ref. 18)
79 (ref. 27)
85 (ref. 15)
90 (ref. 28)
93 (ref. 29)
86 (ref. 30)
93 (this work)
H2O/r.t/alum
H2O/r.t/nano-Al2O3/BF3/Fe3O4
Aqueous ethanol/r.t/Fe3O4@MAP
H2O/r.t/Fe(CF3CO2)3
—/60/catalysta
a
Nano-Fe3O4@walnut shell/Cu(II).
A proposed mechanism for preparation of 2-aryl/alkyl-2,3- recorded at 400 and 100 MHz, respectively. Fourier transform
dihydro-1H-naphtho[1,2-e][1,3]oxazine in the presence of nano- infrared (FT-IR) measurements (in KBr pellets or ATR) were
Fe3O4@walnut shell/Cu(II) was shown in Scheme 2. Cu(II) acti- recorded on a Brucker spectrometer. Melting points were
¨
vate the carbonyl group in formaldehyde and then Mannich- determined on a Buchi B-540 apparatus. The X-ray diffraction
type condensation of the amine 1 and the formaldehyde 2 (XRD) pattern was obtained by a Philips XpertMPD diffrac-
ꢀ
gives intermediate 5. In the next step, the b-naphthol as tometer equipped with a Cu Ka anode (k ¼ 1.54 A) in the 2q
a nucleophile attacked to the intermediate 5 to form interme- range from 10 to 80ꢀ. Field Emission Scanning Electron
diate 6 which was condense with the second molecule of Microscopy (FESEM) was obtained on a Mira 3-XMU. VSM
formaldehyde to give intermediate 7. Ultimately, by an intra- measurements were performed by using a vibrating sample
molecular cyclization the 2-aryl/alkyl-2,3-dihydro-1H-naphtho magnetometer (Meghnatis Daghigh Kavir Co. Kashan Kavir,
[1,2-e][1,3]oxazine derivatives 4 were prepared.
Iran). Energy-dispersive X-ray spectroscopy (EDS) of nano-
As presented in Table 3, the use of nano-Fe3O4@walnut Fe3O4@ walnut shell/Cu(II) was measured by an EDS instrument
shell/Cu(II) resulted in an improved method in terms of reaction and Phenom pro X. Thermal gravimetric analysis (TGA) was
time, compatibility with environment, and yield when conducted using “STA 504” instrument.
compared with other reported catalysts. From environmental
friendly and simplicity of protocol viewpoints, the present
Preparation of nano-walnut shell
report is one of the successful methods and is comparable with
Firstly, the walnut shell was heated in a boiling water for 15
others. Meanwhile, magnetic property of the applied catalyst in
minutes, dried and powdered. Then treated with a 17.5 w/v
this work cause simpler workup and recovery of catalyst than
NaOH solution at 100 ꢀC for 12 h under mechanical stirring.
each other reported procedure.
Subsequently, walnut shell was ltered and washed with
distilled water until the alkali was completely eliminated. It was
then bleached with 100 mL of 1 : 1 aqueous dilution of 3.5% w/v
Conclusions
sodium hypochlorite at 80 ꢀC for 3 h under mechanical stirring.
In summary, we have demonstrated the preparation and charac-
The resulting alpha cellulose was hydrolyzed partially using
terization of nano-Fe3O4@walnut shell/Cu(II) as a novel magnetite
65% sulfuric acid aqueous ꢀsolution with a walnut shell-to-acid
recoverable, eco-friendly, inexpensive and efficient nanocatalyst.
weight ratio of 1–10 at 45 C. Aer 1 h, the obtained suspen-
The catalytic activity of the prepared catalyst was investigated in
sion was diluted with water ve-fold to stop the hydrolysis
the synthesis of 2-aryl/alkyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxa-
reaction. The suspension was centrifuged at 4000 rpm to
zine derivatives through one-pot three-component reaction of b-
separate the nano-walnut shell from acid solution. The washing
naphthol, formaldehyde, and primary amines under solvent-free
with water and centrifuging was repeated four to ve times to
condition at 60 ꢀC. This protocol includes some important
remove any remaining free acid. The yield of obtained nano-
advantages such as mild reaction conditions, short reaction time,
walnut shell is 60%.
excellent yields, easy work-up, high purity of products. And so,
magnetic separation and reusability of nanocatalyst is other
advantages of this protocol.
Preparation of nano-Fe3O4@walnut shell
1 g of nano-walnut shell was dissolved in 100 mL of 0.05 M
acetic acid solution; to which FeCl3$6H2O (3.51 g, 0.013 mol)
and FeCl2$4H2O (1.29 g, 0.0065 mol) were added. The mixture
was stirred for 4 h at 80 ꢀC. As a result, 6 mL of 25% NH4OH was
Experimental
Materials and methods
Chemicals were purchased from Merck, Fluka, and Aldrich added drop wise into the reaction mixture with constant stir-
Chemical Companies. 1H NMR and 13C NMR spectra were ring. Aer 30 min, the mixture was cooled to room temperature
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and then by using an external magnet, nano walnut shell coated
over magnetic nanoparticles were separated. Then magnetic
precipitate rst was washed with distilled water then ethanol,
Conflicts of interest
There are no conicts to declare.
ꢀ
and nally dried at 80 C for 4 h. The nal weight of obtained
nano-Fe3O4@walnut shell is 1.5 g.
Acknowledgements
The Research Council of Yazd University gratefully acknowl-
edged for the nancial support for this work.
Preparation of nano-Fe3O4@walnut shell/Cu(II)
In a ask containing 50 mL of 0.5 M NaOH, nano-Fe3O4@-
walnut shell (0.5 g) was added with stirring. Then, 75 mL of
CuCl2 aqueous solution, 0.04 M, was added. A dark brown
solution was obtained immediately that was stirred at room
temperature. Aer 6 h, the magnetically heterogeneous catalyst,
nano-Fe3O4@walnut shell/Cu(II), removed from solution by an
external magnet. The catalyst washed with ethanol and water
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A mixture of b-naphthol (1.0 mmol), primary amine (1.0 mmol)
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O4@walnut shell/Cu(II) (0.08 g) was stirred at 60 ꢀC under
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6676–6680.
(cmꢁ1): 1593, 1492, 1225, 1092. 1H NMR (acetone-d6, 400 MHz)/
d ppm: 7.84 (t, 2H, 3J ¼ 9.2 Hz, Ar–H), 7.71 (d, 1H, 3J ¼ 8.8 Hz,
Ar–H), 7.53 (t, 1H, 3J ¼ 7.2 Hz, Ar–H), 7.38 (t, 1H, 3J ¼ 7.6 Hz, Ar–
H), 7.24–7.29 (m, 4H, Ar–H), 7.02 (d, 1H, 3J ¼ 8.8 Hz, Ar–H), 5.51
(s, 2H, O–CH2–N), 5.03 (s, 2H, –Ar–CH2–N).
9 M. A. Zolgol, A. R. Moosavi-Zare, P. Moosavi, V. Khakyzadeh
and A. Zare, C. R. Chim., 2013, 16, 962–966.
2-Cyclohexyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine
(Table 2, 4j). Off-white solid, mp 248 ꢀC (d). FT-IR (ATR) ꢁn 10 N. Safajoo, B. F. Mirjalili and A. Bamoniri, RSC Adv., 2019, 9,
(cmꢁ1): 2926, 2852, 1597, 1467, 1227, 1058. 1H NMR (DMSO-d6,
500 MHz)/d ppm: 7.66–7.81 (m, 3H, Ar–H), 7.48 (m, 1H, Ar–H), 11 K. S. Kumar, N. P. Kumar, B. Rajesham, G. Kishan, S. Akula
7.35 (m, 1H, Ar–H), 6.98 (m, 1H, Ar–H), 4.99 (s, 2H, O–CH2–N), and R. K. Kancha, New J. Chem., 2018, 42, 34–38.
4.33 (s, 2H, Ar–CH2–N), 2.70 (m, 1H, CH–N), 1.08–1.86 (m, 10H, 12 N. Latif, N. Mishriky and F. Massad, Aust. J. Chem., 1982, 35,
5CH2). 1037–1043.
2-Hexyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine (Table 2, 13 J. B. Chylinska and T. Urbanski, J. Med. Chem., 1963, 6, 484–
4k). Brown solid, mp 177 ꢀC (d). FT-IR (ATR) ꢁn (cmꢁ1): 2927, 2854,
487.
1597, 1467, 1225, 1057. 1H NMR (DMSO-d6, 500 MHz)/d ppm: 7.80 14 W. J. Weiner, S. A. Factor and J. R. Sanchez-Ramos, J. Neurol.,
(m, 1H, Ar–H), 7.68 (m, 2H, Ar–H), 7.47 (m, 1H, Ar–H), 7.34 (m, 1H, Neurosurg. Psychiatry, 1989, 52, 732–735.
Ar–H), 7.00 (m, 1H, Ar–H), 4.87 (s, 2H, O–CH2–N), 4.25 (s, 2H, –Ar– 15 S. A. Sadaphal, S. S. Sonar, B. B. Shingate and M. S. Shingare,
CH2–N), 2.68 (m, 2H, –CH2–N), 1.53 (m, 2H, CH2), 1.25 (m, 6H, Green Chem. Lett. Rev., 2010, 3, 213–216.
3CH2), 0.84 (m, 3H, CH3). 13C NMR (DMSO-d6, 125 MHz)/d ppm: 16 A. H. Kategaonkar, S. S. Sonar, R. U. Pokalwar,
1278–1283.
14.77, 22.98, 27.23, 28.38, 32.02, 47.87, 52.09, 82.71, 112.97, 119.14,
122.18, 124.13, 127.32, 128.46, 129.21, 129.28, 132.44, 152.42.
A. H. Kategaonkar, B. B. Shingate and M. S. Shingare, Bull.
Korean Chem. Soc., 2010, 31, 1657–1660.
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