Functionalized CoFe2O4/lamellar mesopore silica anchored to melamine nanocomposite as a novel catalyst for synthesis of 4H-chromenes under mild conditions

Article abstract of DOI:10.1002/aoc.5630

In this research, it was displayed an efficient method for the one-pot reaction of cyclohexanone, benzaldehyde and malononitrile for the synthesis of 4H-chromenes by using CoFe₂O₄/lamellar mesopore silica anchored to melamine as a magnetic nanocatalyst. This nanocatalyst was prepared in several steps and discriminated by XRD, FT-IR, SEM, VSM, TGA and BET techniques. The catalyst has a large active base site that has functionalized in both the surface and the pore of nanostructure. The advantages of magnetic nanocatalyst were simple accessible, heterogeneous nanocatalyst, easy work up and reusability. The various derivatives of 4H-chromenes were synthesized in the presence of CoFe₂O₄/lamellar mesopore silica/melamine magnetic nanocatalyst with the excellent yields and appropriate times. The products were identified by the melting point, FT-IR, ¹H NMR, ¹³C NMR and C.H.N techniques.

Full text of DOI:10.1002/aoc.5630

Received: 12 October 2019
DOI: 10.1002/aoc.5630
Revised: 10 February 2020
Accepted: 11 February 2020
F U L L P A P E R
Functionalized CoFe2O4/lamellar mesopore silica anchored
to melamine nanocomposite as a novel catalyst for
synthesis of 4H-chromenes under mild conditions
Somaye Mohammadi | Hossein Naeimi
Department of Organic Chemistry,
In this research, it was displayed an efficient method for the one-pot reaction
of cyclohexanone, benzaldehyde and malononitrile for the synthesis of 4H-
chromenes by using CoFe2O4/lamellar mesopore silica anchored to melamine
as a magnetic nanocatalyst. This nanocatalyst was prepared in several steps
and discriminated by XRD, FT-IR, SEM, VSM, TGA and BET techniques. The
catalyst has a large active base site that has functionalized in both the surface
and the pore of nanostructure. The advantages of magnetic nanocatalyst were
simple accessible, heterogeneous nanocatalyst, easy work up and reusability.
The various derivatives of 4H-chromenes were synthesized in the presence of
CoFe2O4/lamellar mesopore silica/melamine magnetic nanocatalyst with the
excellent yields and appropriate times. The products were identified by the
melting point, FT-IR, 1H NMR, 13C NMR and C.H.N techniques.
Faculty of Chemistry, University of
Kashan, Kashan 87317-51167, I, R, Iran
Correspondence
Hossein Naeimi, Department of Organic
Chemistry, Faculty of Chemistry,
University of Kashan, Kashan,
87317-51167, I.R. Iran.
Email: naeimi@kashanu.ac.ir
Funding information
University of Kashan, Grant/Award
Number: Grant No. 159148/97
K E Y W O R D S
4H-Chromene, cyclohexanone, lamellar, Malononitrile, Mesopore silica
1 | INTRODUCTION
an aldehyde, cyclic ketone and malononitrile in the
attendance of various organic and inorganic
The chromene compounds have the significant biological
catalysts.[21,22]
properties,[1]
for
example,
anticancer,[2,3]
Surfactant-template mesoporous silicate obtains the
anticonvulsant,[4]
antibacterial,[5]
antimicrobial,[6]
wide application in catalysis,[23,24] drug delivery,[25,26]
gas filtration,[27,28] sensors[29] and also as nano-sized
quantum materials.[30] The large-area of mesoporous sil-
icate caused applications in optical coatings and func-
tionalization to catalytically processes.[31] The bulk
mesophase managed with the silica-to-surfactant ratio
and formation of cubic, lamellar, hexagonal, that this
phase due to silica/surfactant self-assembly and so
charge matching at the interface.[32] Recently, the
heterogeneous[33–36] catalysts were used to synthesis of
organic compounds because of high activity and
antimalarial,[7] anti-influenza[8] and anti-virus[9] activi-
ties. One of the chromene derivatives is tetrahydro-
4H-chromenes.[10] Also, tetrahydro-4H-chromenes can
be applied as cognitive enhances, for the cure of neuro-
degenerative
illnesses,[11]
counting
Huntington's
disease,[12] amyotrophic lateral sclerosis[13] and
Alzheimer's disease,[14] Parkinson's disease[15] and that
also use for improving schizophrenia.[16] The typical
process to synthesize the tetrahydro-4H-chromene
derivatives is commonly a two-step reaction between a
Michael acceptor and carbonyl compounds in the
attendance of a catalyst.[17–20] Several multi-component
reactions have been defined for the synthesis of differ-
ent tetrahydro-4H-chromenes through condensation of
recoverability.[37–41]
Synthesis
of
tetrahydro-4H-
chromenes was tested by using different catalysts,
method and solvent. Though many of these techniques
have drawbacks, for example, low yields of products,
Appl Organometal Chem. 2020;e5630.
wileyonlinelibrary.com/journal/aoc
© 2020 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.5630

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MOHAMMADI AND NAEIMI
toxic solvents, long reaction times and tedious work-ups
so, different mesopore nanocatalyst was tested.
colored gel waꢀs formed and at the end, the product
burned at 800 C for 3 hr.
2 | EXPERIMENTAL
2.1 | Chemicals
2.2.2 | Synthesis of CoFe2O4/lamellar
mesopore silica/melamine
In order to prepare nitrogen containing base
All the reactants and solvents that used in the reaction
contain the pure cyclohexanone, benzaldehyde,
cetyltrimethyl ammonium bromide (CTAB), sodium
hydroxide (NaOH), tetraethyl orthosilicate (TEOS), were
obtain from Sigma, ferric (III) chloride (FeCl3), cobalt
(II) chloride (CoCl2) and sodium bicarbonate were
purchased from Sinopharm Chemical Company. The
nanocatalysts,
initially,
2,4,6-triamino-1,3,5-triazine
(10 mmol) mixed with 3-chloropropyltrimethoxysilane
(10 mmol) and sodium bicarbonate (5 mmol) in 30 ml
dry toluene solvent and the mixture refluxed for 32 hr.
The reaction product was assembled by centrifuge and
washed three times with water and ethanol, respectively
and then the product dried at 70 ꢀC under nitrogen
atmosphere.[42] In a distinguishing synthesis, 10 mL
NaOH 2 M, and 0.5 g of CTAB dissolved in 100 ml dis-
1
organic products were identified by H NMR and FT-IR
analyses. The 1H NMR were recorded in CDCl3 and
DMSO-d6 solvents using of Bruker DRX-400 spectrometer
and the tetramethylsilane as internal reference. FT-IR
spectra attained with KBr pellets with a Perkin-Elmer
550 spectrometer in the range of 400–4000 cm−1. The
TGA spectra recorded in an air atmosphere with a
ꢀ
tilled water and heated at 100 C for 30 min. After that
0.1 g of CoFe2O4 nanoparticles were dispersed in 60 ml
ethanol with sonication and added to the reaction mix-
ture. After 10 min, 2 ml TEOS and 10 ml ethanol and
so after 40 min, 2 ml TEOS, 0.5 g SiO2@melamine and
10 ml ethanol added with strong stirring. NaOH has
two roles in this process, one of them was presentations
as a catalyst for the sol–gel technique and the other
etchant role for structural progress. The reaction stirred
at room temperature for 12 hr, the corresponding prod-
uct was collected by centrifuge and washed withꢀwater
and ethanol. Then, the product was dried at 70 C for
24 hr. At the end to remove the surfactant from the
nanostructure, the prepared compound dispersed in the
ethanol (150 ml) and ammꢀonium nitrate (72 mg) and
the reaction followed at 70 C for 4 hr. The finalꢀprod-
uct separated with the centrifuge and dried at 80 C for
overnight (Scheme 1).
ꢀ
10 C/min rate and register via METLER-810 analyzer.
The crystal structure of nanoparticle (XRD) recorded
with (CuKa, radiation, λ = 0.154056 nm), and by
the speed of 2ꢀ min−1 beginning 10ꢀ to 80ꢀ (2ϴ). For
determination of the composition and morphology of
nanoparticles, it was used of Zeiss Scanning Electron
Microscope (SEM) that worked with a 15 kV accelerating
voltage. The surface areas and the size of pore in the
nanostructure was displayed by BET analysis thatꢀassign-
ment by nitrogen adsorption–desorption in −196 C that
recorded by Tristar 3020, Micromeritics Electron Micro-
scope. The magnetic properties of nanostructure were
measured by a vibrating sample magnetometer (VSM)
with PPMS-9 T at 300 K.
2.3 | General multicomponent
procedure for synthesis of 4H-chromene
2.2 | General procedure for preparation
of nanocatalyst
4H-chromene synthesized from the multi-component
reaction. In this process, 0.104 ml (1 mmol) of cyclohexa-
none and 0.102 mL (1 mmol) of the benzaldehyde mixed
in an ethanol solvent, then 10 mg of nanocatalyst added
to the reaction mixture and stirred at room temperature
for 10–15 min. When completed the first step of the reac-
tion, 0.066 g (1 mmol) of the malononitrile added to the
flask of reaction and the process monitored with thin
layer chromatography. For separation and purification of
the product, 5 ml water added to the mixture, the final
product washed with cold ethanol. Then, the resulting
solid product was resolved in the minimum of ethanol
solvent and recrystallized to give 2-amino-4-phenyl-
2.2.1 | General procedure for
preparation of CoFe2O4 nano magnetic
The cobalt ferrite nanoparticles prepared via sol–gel
technique.[42] To achieve the chemical formula
CoFe2O4, at the first 30 mL FeCl3 6 H2O (4 M) was
combined to 30 ml CoCl2 2H2O (2 M), then added
1 g citric acid monohydrate (C6H8O7 H2O) as the sur-
factant to the reaction mixture. After that, the pH of
the solution increased to 7.0 with a little ammonia-
water (NH3-H2O). Then was heated the reaction mix-
ture to evaporate the water at 85 ꢀC and the brown

COFE2O4 NANOCOMPOSITE CATALYZED SYNTHESIS OF 4H-CHROMENES
3 of 11
SCHEME 1 preparation of CoFe2O4/lamellar mesopore silica/melamine nanocatalyst
5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile as the
pure product. The final product recognized by the melt-
ing point, FT-IR and 1H NMR spectra.
2.43–2.46 (d, J = 10.4 Hz, 1H), 2.01–2.05 (d, J = 17.1 Hz,
1H), 1.76–1.77 (d, J = 6.5 Hz, 2H), 1.39–1.61 (m, 2H), 13
NMR (400 MHz, Chloroform-d) δ 22.20, 26.999, 27.39,
42.90, 60.46, 115.07, 115.33, 115.81, 119.81, 121.76,
129.49, 130.89, 138.62, 158.82, 160.90, Anal. calcd (%) for
C16H15 F N2O: C 71.11, H 5.55, N 10.37. Found (%): C
71.12, H 5.55, N 10.36.
C
2-amino-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-
3-carbonitrile (4a); White solid; m.p.: 233–235 ꢀC (Lit. m.
p 240–241 C)[43]; IR (KBr) v = 3453, 3317, 3177, 2954,
ꢀ
2828, 2183, 1668, 1629 1483, 1411, 1382, 1253, 1132, 1069,
1
819, 514 cm−1; H NMR (400 MHz, CDCl3) δ 7.33–7.37
2-amino-4-(4-(dimethylamino)phenyl)-5,-
(m, 4H), 6.88 (s, 1H), 4.52 (s, 1H), 3.97 (s. 2H, NH2),
2.68–2.77 (m, 1H), 2.54–2.64 (m, 1H), 1.93–2.05 (m, 2H),
1.46–1.72 (m, 4H).
6,7,8-tetrahydro-4H-chromene-3-carbonitrile (4e); Yel-
low solid; m.p.: 223–225 C; IR (KBr) v = 3445, 3325,
ꢀ
3021, 2892, 2835, 2192, 1668, 1635 1595, 1417, 1247,
2-amino-4-(4-bromophenyl)-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4b); White solid; m.p.:
220–222 ꢀC; IR (KBr) v = 3446, 3335, 3235, 2935,
2863, 2214, 1667, 1663 1595, 1484, 1413, 1258, 1128,
1133, 754, 699, 561 cm−1 1H NMR (400 MHz,
,
Chloroform-d) δ 7.18–7.19 (d, J = 7.0 Hz, 1H), 7.14
(s, 2H), 6.84 (s, 1H), 4.49 (s, 2H, NH2), 3.93 (s, 1H),
2.69–2.72 (d, J = 9.0 Hz, 1H), 2.58 (m, 1H), 2.36
(s, 3H), 2.34 (s, 3H), 1.97–1.99 (d, J = 5.1 Hz, 2H),
1.62 (m, 4H).).13C NMR (400 MHz, Chloroform-d)
δ22.49,24.64, 25.02, 40.15, 41.14, 59.99, 11.61, 114.98,
119.29, 133.84, 154.23, 158.15, Anal. calcd (%) for
C18H21 N3O: C 73.12, H 7.15, N 14.21. Found (%): C
73.13, H 7.16, N 14.23.
1
1008, 822, 512 cm−1, H NMR (400 MHz, Chloroform-
d) δ 7.47 (m, 1H), 7.13–7.17 (m, 2H), 6.79 (s, 1H), 4.54
(s, 2H, NH2), 3.95 (s, 1H), 2.66 (s, 1H), 2.54 (s, 1H),
1.94–1.98 (d, J = 17.5 Hz, 2H), 1.57–1.63 (d, J = 24.8 Hz,
4H); 13C NMR (100 MHz, Chloroform-d) δ 157.29,
146.81, 142.81, 128.64, 117.69, 116.60, 114.98, 55.17,
40.20, 36.31, 29.44, 25.02; Anal. calcd (%) for C16H15
Br N2O: C 57.90, H 4.54, N 8.45. Found (%): C 57.92,
H 4.53, N 8.45.
2-amino-4-(2,4-dichlorophenyl)-5,6,7,8-tetrahydro-
4H-chromene-3-carbonitrile (4f); White solid; m.p.:
ꢀ
130–132 C; IR (KBr) v = 3466, 3319, 3180, 2942, 2836,
2-amino-4-(3-nitrophenyl)-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4c); Yellow solid; m.p.:
120–122 C; IR (KBr) v = 3460, 3363, 3085, 2931, 2863,
2186, 1669, 1631 1596, 1486, 1410, 1259, 1090,
824, 512 cm−1,1H NMR (400 MHz, Chloroform-d) δ
7.38–7.45 (m, 1H), 7.20–7.24 (dd, J = 18.6, 10.7 Hz, 1H),
6.85 (s, 1H), 4.64–4.67 (s, 2H, NH2), 3.70–3.74 (q,
J = 7.0 Hz, 1H), 2.34–2.65 (m, 2H), 2.18–2.01 (m, 1H),
1.87 (m, 1H), 1.59–1.62 (d, J = 12.2 Hz, 2H), 1.37–1.52
(m, 1H), 1.23–1.26 (t, J = 7.0 Hz, 1H).); 13C NMR
(100 MHz, Chloroform-d) δ 164.54, 145.69, 141.70,
138.39, 135.55, 131.86, 127.14, 124.27, 119.29, 114.98,
56.17, 44.24, 34.07, 27.97, 22.89; Anal. calcd (%) for
C16H15Cl2N2O: C 59.77, H 4.35, N 8.71. Found (%): C
59.79, H 4.5636, N 8.72.
ꢀ
2189, 1669, 1633 1527, 1410, 1349, 1130, 809, 735,
680 cm−1, 1H NMR (400 MHz, Chloroform-d) δ 8.11–8-17
(d, J = 22.4 Hz, 1H), 7.63–7.65 (m, 2H), 6.95 (s, 1H), 4.68
(s, 2H, NH2), 4.16 (s, 1H), 2.66–2.79 (m, 1H), 2.59–2.62
(d, J = 11.7 Hz, 1H), 2.06–2.10 (d, J = 17.6 Hz, 1H),
1.83–1.99 (m, 1H), 1.45–1.77 (m, 4H), 13C NMR
(400 MHz, Chloroform-d) δ22.14, 27.12, 39.39, 59.29,
119.67, 120.03, 126.26, 127.67, 128.32, 128.61, 129.52,
130.68, 159.43,Anal.calcd (%) for C16H15N3O3: C 64.57, H
5.13, N 14.40. Found (%): C 64.56, H 5.11, N 14.42.
2-amino-4-(4-nitrophenyl)-5,6,7,8-tetrahydro-4H-
2-amino-4-(4-fluorophenyl)-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4 g); Yellow solid; m.p.:
ꢀ
chromene-3-carbonitrile (4d); White solid; m.p.:
180–183 C; IR (KBr) v = 3466, 3378, 2934, 2191, 1640,
223–225 C; IR (KBr) v = 3448, 3346, 3057, 2955, 2863,
1517, 1443, 1343 11032, 855, 705 cm-1, 1HNMR (400 MHz,
DMSO-d6) δ 8.23 (s, 2H, NH2) 7.57–7.59 (d, J = 8.5 Hz,
1H), 7.49–7.50 (d, J = 8.3 Hz, 1H), 7.07(s, 1H), 7.02(s,
1H), 4.27 (s, 1H), 2.62–2.77 (m, 1H), 2.54–2.56 (d,
J = 7.1 Hz, 1H), 2.03–2.19 (m,2H), 1.71–1.88 (m, 2H),
ꢀ
2187, 1671, 1635 1592, 1412, 1254, 1139, 700, 515 cm−1
,
1H NMR (400 MHz, DMSO-d6) δ 7.33–7.37 (d, J = 8.2 Hz,
1H), 7.20 (s, 2H, NH2), 6.93 (s, 1H), 6.81 (s, 2H), 4.00 (s,
1H), 3.34 (s, 1H), 2.59–2.62 (d, J = 15.3 Hz, 1H),

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MOHAMMADI AND NAEIMI
1.56–1.57 (d, J = 4.6 Hz, 2H); 13C NMR (100 MHz,
Chloroform-d) δ 158.15, 145.32, 140.19, 129. 95, 124.96,
121.48, 117.69, 56.23, 42.24, 29.40, 25.02, 19.94 Anal.
calcd (%) for C16H15N3O3: C 64.57, H 5.13, N 14.40.
Found (%): C 64.58, H 5.14, N 14.43.
2929, 2211, 1644, 1601, 1489, 1391, 1275, 1076,
1
835, 510 cm−1; H NMR (400 MHz, DMSO-d6) δ 7.57
(s, 2H), 7.53 (s, 1H), 7.13–7.25 (m, 1H) 6.91 (s, 2H, NH2),
3.99 (s, 1H), 2.64–2.67 (d, J = 14.9 Hz, 1H), 2.23–2.27
(d, J = 12.6 Hz, 1H), 2.15–1.91 (m, 2H), 1.91–1.61
(m, 2H), 1.53 (d, J = 19.2 Hz, 1H), 0.84 (s, 3H) Anal. calcd
(%) for C22H20N2O: C, 80.46; H, 6.14; N, 8.53; Found
(%): C, 80.89; H 6.31; N, 8.58.
2-amino-4-(4-chlorophenyl)-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4 h); White solid; m.p.:
ꢀ
274–277 C; IR (KBr) v = 3421, 3343, 3252, 2944, 2212,
1
1645, 1606, 1492, 1389, 1212, 1095, 805, 514 cm−1; H
NMR (400 MHz, CDCl3) δ 7.31–7.34 (m, 2H), 7.18–7.23
(dd, J = 18.6, 10.7 Hz, 2H), 4.55 (s, 2H, NH2), 3.96
(s, 1H), 2.65–2.68 (m, 1H), 2.55(s, 1H), 1.93–2 (m, 2H),
1.62–1.67 (m, 3H), 1.25 (s,1H). Anal. calcd (%) for
C16H15ClN2O C, 67.02; H, 5.27; N, 9.77;Found (%): C
67.92, H 5.64, N 9.50.
3 | RESULTS AND DISCUSSION
3.1 | Preparation and chracterization of
catalyst
2-amino-6-methyl-4-phenyl-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4i); White solid; m.p.:
CoFe2O4/lamellar
mesopore
silica/melamine
nanocatalyst prepared in two-step. At the first, the
CoFe2O4 nanoparticles were synthesized through
sol–gel method and then, the TEOS, SiO2/Melamine,
surfactant and NaOH added to the mixture. The role of
surfactant and NaOH can be the creation the pore in
the nanocatalyst and design the morphology of nano-
structure (Scheme 1).
After preparation of magnetic CoFe2O4/lamellar
mesopore silica/melamine nanocatalyst, it was identified
with different analyses such as; XRD, FT-IR, SEM,
VSM and TGA. The X-ray diffraction patterns of
magnetic CoFe2O4 and CoFe2O4/lamellar mesopore sil-
ica/melamine nanocatalyst were displayed in Figure 1.
The situation of all peaks in the both the curves
confirmed with regular XRD pattern[44] of JCPDS card.
The XRD pattern of CoFe2O4 displays the crystal struc-
ture and the XRD of CoFe2O4/lamellar mesopore sil-
ica/melamine displays the crystal and amorphous
structure (Figure 1).
ꢀ
202–203 C; IR (KBr) v = 3417, 3338, 3252, 2935, 2211,
1
1649, 1602 1453, 1391, 1275, 1080, 712, 580 cm−1; H
NMR (400 MHz, DMSO-d6) δ 7.38 (s, 1H), 7.33 (s, 1H),
7.25–7.27 (d, J = 7.1 Hz, 1H), 7.17–7.19 (d, J = 7.7 Hz,
1H), 6.96 (s, 1H), 6.78 (s, 2H, NH2), 3.93 (s, 1H), 2.70 (d,
J = 13.1 Hz, 1H), 2.33–1.94 (m, 2H), 1.83–1.85 (m, 2H),
1.62–1.44 (m, 1H), 0.83 (t, J = 7.2 Hz, 4H); Anal. calcd
(%) C17H18N2O: C, 76.66; H, 6.81; N, 10.52 Found (%): C,
76.84.; H 6.53, N, 10.45.
2-amino-4-phenyl-6-propyl-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4j); White solid; m.p.:
ꢀ
230–232 C; IR (KBr) v = 3446, 3356, 3204, 2943, 2215,
1625, 1593, 1476, 1339, 1270, 1189, 1052, 880, 563 cm−1
;
1H NMR (400 MHz, DMSO-d6) δ 7.36 (s, 1H), 7.32 (s,
1H), 7.21–7.26 (d, J = 7.0 Hz, 1H), 7.19 (s, 1H), 6.95 (s,
1H), 6.79 (s, 2H, NH2), 3.95 (d, J = 10.0 Hz, 1H),
2.70–2.73 (d, J = 13.5 Hz, 1H), 2.30 (s, 1H), 2.08 (s, 1H),
1.83–1.85 (d, J = 7.6 Hz, 2H), 1.44–1.47 (d, J = 44.1 Hz,
2H), 1.13–1.16 (d, J = 12.8 Hz, 4H), 0.72 (s, 3H), Anal.
calcd (%) for C19H22N2O: C, 77.52; H, 7.53; N, 9.52; O,
5.43 Found (%): C, 77.92; H 7.59; N, 9.87.
The pattern of the CoFe2O4 nanoparticles was inde-
xed as a face-centered cubic structure, which is very close
to the values in the literature (JCPDS No. card no
22–1086). The crystallite size for nanoparticles were cal-
culated and reported in Table 1.
2-amino-4,6-diphenyl-5,6,7,8-tetrahydro-4H-
chromene-3-carbonitrile (4 k); White solid; m.p.:
ꢀ
250–252 C; IR (KBr) v = 3422, 3327, 3224, 2914, 2212,
In the FT-IR spectra of the CoFe2O4, SiO2/melamine
and CoFe2O4/SiO2/Melamine were investigated and the
results were shown in Figure 2. The FT-IR spectra of the
CoFe2O4the peaks appeared about 440 and 549 cm−1 due
to the stretching vibrations of Co-Fe bonding. The peak
that place about 1631 cm−1 due to bending vibration and
the peak of 3414 cm−1 due to the stretching vibration of
O-H bonding. In the FT-IR spectra of SiO2/melamine the
peaks of 3468, 3418, 3339 cm−1 related to stretching
vibrations of N-H bond, the peak around of 3132 cm−1
related to stretching vibration of C-H, sp2 bonding, the
peaks of 1653 and 1438 cm−1 due to aromatic ring and
the peak of 1553 cm−1 related to C=N stretching
1
1644, 1599, 1494, 1390, 1265, 754, 569 cm−1; H NMR
(400 MHz, DMSO-d6) δ 7.62–7.61 (d, J = 7.9 Hz, 1H),
7.46 (s, 2H, NH2), 7.43 (s, 4H), 7.23–7.19 (t, J = 7.4 Hz,
2H), 7.14–7.10 (m, 3H), 4.34 (s, 1H), 3.63–3.60
(d, J = 12.4 Hz, 1H), 3.12–3.07 (m, 1H), 2.29–2.90 (m,
1H), 2.44–2.40 (m, 1H), 2.22–2.15 (m, 1H), 1.51–1.48
(d, J = 12.4 Hz, 1H), 1.25–119 (q, J = 12.1 Hz, 1H), Anal.
calcd (%) for C17H17BrN2O C, 59.14; H, 4.96; N, 8.11;
Found (%): C, 59.69; H 5.21; N, 8.57.
2-amino-4-(4-bromophenyl)-6-methyl-5,-
6,7,8-tetrahydro-4H-cꢀhromene-3-carbonitrile (4 l); White
solid; m.p.: 280–283 C; IR (KBr) v = 3423, 3344, 3251,

COFE2O4 NANOCOMPOSITE CATALYZED SYNTHESIS OF 4H-CHROMENES
5 of 11
FIGURE 1 XRD spectra of CoFe2O4, CoFe2O4/lamellar
FIGURE 2 The spectra of FT-IR CoFe2O4, SiO2/Melamine,
CoFe2O4/SiO2/Melamine
mesopore silica/melamine
TABLE 1 The peak position, full width at half maximum (β ½) and calculated crystal size for nanoparticles
CoFe2O4/lamellar mesopore silica/melamine
ʎ = 0.154 nm, K = 0.94, Pos. [ꢀ2Th.]FWHM Left [ꢀ2Th.]1
Element
2ϴ position(ꢀ)
β ½
(111)
18.12
0.94
(220)
30.27
0.47
(222)
37.28
0.41
(400)
43.47
0.47
(422)
53.88
1.41
(511)
57.16
0.70
(440)
62.28
0.47
(533)
73.99
1.41
Size (nm)
8.93
18.27
21.34
18.99
6.60
13.49
20.61
7.36
vibration, the peak of around 1124 cm−1 due to C-O, and
the peak of 1030 cm−1 related to Si-O stretching
vibration.[44]
SEM images of CoFe2O4/lamellar mesopore sil-
ica/melamine were displayed in Figure 3. The several
layers of these plates next to each other formed the lamel-
lar mesopore silica. The average size of the nanoparticles
is 26 nm. The obtained nanoparticles size from the SEM
was very close with the calculated size from XRD tech-
niques (Table 1).
(Figure 4). Displaying the N2 adsorption–desorption
isotherms and hysteresis loop, along with BET plot,
was provided better confirmation of the mesoporous
structure. The BET analysis of the nanoparticles shows
a surface area about 619 m2g−1, the pore size of the
mesopore compound equal to 2.11 nm, and the p/pᴏ of
the nanoparticle reported 0.327 cm3g−1
.
To investigate the magnetic properties of CoFe2O4/
lamellar mesopore silica/melamine nanoparticles
examined the vibrating sample magnetometry (VSM)
spectrum of the compound with Ms 80 emu/g
(Figure 5).
Furthermore, the mesoporous structure of synthetic
compound has been demonstrated by BET analysis

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MOHAMMADI AND NAEIMI
FIGURE 5 VSM curves for CoFe2O4/lamellar mesopore
silica/melamine
FIGURE 3 FE-SEM image of CoFe2O4/lamellar mesopore
silica/melamine
FIGURE 6 TGA curves for CoFe2O4/lamellar mesopore
silica/melamine
3.2 | Investigation of catalytic activity
In order to optimize the protocol, cyclohexanone,
benzaldehyde and malononitrile for the synthesis of 4H-
chromene, considered in the presence of various cata-
lysts, solvents and temperatures (Scheme 2). At first, the
reaction was carried out in the attendance of altered
catalyst in a different amounts at ethanol solvent
(Table 2). At the result, the best catalyst for the reaction
was nanomagnetic CoFe2O4/lamellar mesopore sil-
ica/melamine with the large surface area and attended of
the melamine function in the surface and pore. The reac-
tion carried out in the attendance of 0.1 mg of
nanocatalyst (Table 2, entry 2).
FIGURE 4 BET curves for CoFe2O4/lamellar mesopore
silica/melamine
Thermogravimetric analysis (TGA) curves of
CoFe2O4/lamellar mesopore silica/melamine (Figure 6)
show that the losses weight under 200 ꢀC that in all
models are endorsed to tꢀhe freedom of adsorbed water.
TGA analysis in 400–800 C showed the losses melamine
that displays the weight due to destroy the structure of
nanocatalyst. Consequently, the weight % of the organic
compound that anchored to the CoFe2O4/lamellar meso-
pore silica was calculated 23% due to loss the weight
between 300–800 ꢀC.
The different solvents examined to check the effect of
them in the model reaction. At the results, the reaction
in the ethanol solvent has an excellent yield in a short
time (Table 3).

COFE2O4 NANOCOMPOSITE CATALYZED SYNTHESIS OF 4H-CHROMENES
7 of 11
SCHEME 2 Synthesis of 4H-chromene in
different condition
TABLE 2 Investigation of catalyst in multicomponent reaction
and after 7–10 min malononitrile (1 mmol) added to
the mixture (Scheme 3). The best solvent that selects
for the reaction was ethanol (5 ml). The reaction
stirred for 10–15 min at room temperature. In this
condition, the 4-H-chromene derivatives with electron
donating and electron withdrawing synthesized in
excellent yields (Table 5).
for synthesis of 4H-chromenea
Catalyst
amount
(mg)
Time
Yield
Entry Catalyst
(min) b (%)
1
2
3
4
5
Guanidine
Melamine
MgFe2O4
MgO
10 mg
10 mg
10 mg
10 mg
10 mg
90
80
60
60
45
70
75
80
82
85
3.3 | Proposed reaction mechanism
CoFe2O4/SiO2/
melamine
The mechanism of reaction for the synthesis of 4H-
chromenes contained several steps, in the first step cyclo-
hexanone and benzaldehyde reacted together with con-
densation reaction and synthesis of the α,β-unsaturated
intermediate under the nanomagnetic base CoFe2O4/
lamellar mesopore silica/melamine catalyst. This catalyst
has the grate base activity because of the large active base
site in both surface and pore. Then the malononitrile
under Michael addition join to the C=C bond for the syn-
thesis of intermediate G, then processes followed with
cyclization by the formation of C–O bond. At the end of
the reaction, 4H-chromene (4a) synthesized with the
elimination of a hydrogen and rearrangement of double
bonds (Scheme 4).
The CoFe2O4/lamellar mesopore silica/melamine
simple separated with magnetic properties and recyclabil-
ity for six runs (Figure 7). After each of the reaction, the
catalyst separated and washed three times with acetone
and used in the other reaction. The recycled catalyst
could be reused for six times without considerable loss of
its catalytic activity and gave the corresponding product
in high yields.
6
7
CoFe2O4/lamellar
mesopore
silica/melamine
10 mg
5 mg
20
30
93
82
CoFe2O4/lamellar
mesopore
silica/melamine
aReaction conditions: cyclohexanone (1 mmol), malononitrile (1 mmol),
benzaldehyde (1 mmol), room temperature, ethanol solvent (5 ml).
bIsolated yield.
TABLE 3 Investigation of solvent in multicomponent reaction
for synthesis of 4H-chromene a
Entry
Solvent
Yield b (%)
Time (mine)
1
2
3
4
Chloroform
Dichloromethane
Methanol
85
80
87
93
45
40
35
20
Ethanol
aReaction conditions: cyclohexanone (1 mmol), malononitrile (1 mmol),
benzaldehyde (1 mmol), room temperature, nanocatalyst (10 mg).
bIsolated yield.
To survey the influence of temperature on the yield of
4H-chromene proꢀduct, theꢀreaction was study in various
temperatures (25 C to 80 C) (Table 4). At the result the
best temperature for the reaction was the ambient
temperature.
TABLE 4 Investigation of various temperatures in
multicomponent reaction for synthesis of 4H-chromene a
Entry
Temperature
Yield b (%)
Time (mine)
1
2
3
4
25
35
45
60
93
85
80
75
20
15
15
15
After optimization, it was selected as the best
condition for the synthesis of 4H-chromene under
the
CoFe2O4/lamellar
mesopore
silica/melamine
nanocatalyst. In this reaction, the variety derivatives of
benzaldehyde (1 mmol), different derivatives of cyclo-
hexanone (1 mmol) and nanocatalyst (10 mg) mixed
aReaction conditions: cyclohexanone (1 mmol), malononitrile (1 mmol),
benzaldehyde (1 mmol), ethanol solvent (5 ml), nanocatalyst (10 mg).
bIsolated yield.

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MOHAMMADI AND NAEIMI
SCHEME 3 synthesis of 4H-cheromene from
cyclohexanone, benzaldehyde and malononitrile
TABLE 5 Synthesis of various derivatives of 4H-cheromene in the presence of CoFe2O4/lamellar mesopore silica/melamine
nanocatalyst
4a-l a, Yield % b, Time (min)
TON, TOF (h−1
)
4a: X = H, Y = H, 90, 30
50, 100
4c: X = NO2, Y = H, 90, 35
50, 86.2
4b: X = Br, Y = H, 88, 30
48.8, 97.6
4d: X = F, Y = H, 89, 20
49.4, 149.6
4f: X = 2,4 dichloro, Y = H, 86, 35,
47.7, 89.2
4e: X = N,N dimethyl, Y = H,
88, 45, 48.8, 65.1
4 h: X = Cl, Y = H, 93, 35,
51.7, 89.1
4 g: X = NO2, Y = H, 93, 25
51.7, 126.0
4i: X = H, Y = CH3, 92, 25,
51.1, 124.6
4 l: X = H, Y = Ph, 94, 20,
52.2, 158.2
4 k: X = Br, Y = CH3, 90, 27,
50, 111.1
4j: X = H, Y = C3H7, 91, 20,
50.6, 153.2
aReaction conditions: benzaldehyde (1 mmol), cyclohexanone (1 mmol), malononitrile (1 mmol), 0.1 mmol nanocatalyst (10 mg), ethanol solvent (5 ml), r.t.
bIsolated yield.

COFE2O4 NANOCOMPOSITE CATALYZED SYNTHESIS OF 4H-CHROMENES
9 of 11
SCHEME 4 Proposed reaction mechanism for the
synthesis of 1H-isochoromene
FIGURE 7 The recyclability of CoFe2O4/lamellar mesopore
silica/melamine in six runs
FIGURE 8 FE-SEM image of CoFe2O4/lamellar mesopore
silica/melamine after recycling
Also, the leaching of the nanocatalyst was investi-
gated with the hot filtration. The reaction of benzalde-
hyde, cyclohexanone, and malononitrile at the presence
of nanocatalyst was stopped after 5 min and the
nanocatalyst filtered from the reaction mixture. The fil-
trate was heated and the reaction followed and checked
with thin layer chromatography. The reaction did not
progress after filtration, so the negative consequences of
hot filtration test show that the leaching of nanocatalyst
is insignificant.
mesopore silica/melamine catalyst. The SEM image of
this catalyst explored to determine the morphology of the
nanocatalyst after recycling of the nanocatalyst. So, the
result displayed the nanocatalyst retain the lamellar mor-
phology (Figure 8).
4 | CONCLUSION
For investigating the properties of nanoparticles after
recycling and reusing in 6 runs of reactions, it was exam-
ined the SEM analysis of recovered CoFe2O4/lamellar
In this research, it was functionalized the CoFe2O4/
lamellar mesopore silica magnetic nanoparticles with

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MOHAMMADI AND NAEIMI
[14] S. Zavar, Arab. J. Chem. 2017, 10, S67.
[15] M. A. Ameen, S. M. Motamed, F. F. Abdel-latif, Chin. Chem.
Lett. 2014, 25, 212.
the melamine compound. The mesopore silica with a
large area has a great surface area to functionalization.
So, the CoFe2O4/lamellar mesopore silica/melamine
has a strong basic activity. In this protocol, for exami-
nation of the catalytic activity of nanoparticles, the
synthesis of 4H-chromenes was studied. It was found
that the reaction by using CoFe2O4/lamellar mesopore
silica/melamine as a nanocatalyst has excellent yields
and short reaction times in this reaction. The
nanocatalyst was characterized by FT-IR, XRD, SEM,
TGA, VSM techniques and the organic products identi-
[16] M. Amirnejad, M. R. Naimi-Jamal, H. Tourani, H. Ghafuri,
Monatshefte für Chemie-Chemical Mon. 2013, 144, 1219.
[17] R. Tayebee, A. Pejhan, H. Ramshini, B. Maleki, N. Erfaninia,
Z. Tabatabaie, E. Esmaeili, Appl. Organomet. Chem. 2018, 32,
e3924.
[18] B. Maleki, Org. Prep. Proced. Int. 2016, 48, 81.
[19] B. Maleki, M. Baghayeri, S. Sheikh, S. Babaee, S. Farhadi,
Russ. J. Gen. Chem. 2017, 87, 1064.
[20] B. Maleki, S. Sheikh, RSC Adv. 2015, 5, 42997.
[21] W.-B. Sun, P. Zhang, J. Fan, S.-H. Chen, Z.-H. Zhang, Synth.
Commun. 2010, 40, 587.
[22] J. M. Khurana, B. Nand, P. Saluja, J. Heterocyclic Chem. 2014,
51, 618.
1
fied with the melting point, FT-IR and H NMR ana-
lyses (see Supporting information).
ACKNOWLEDGEMENTS
The authors are grateful to University of Kashan for
supporting this work by Grant No. 159148/97.
[23] T. Maschmeyer, F. Rey, G. Sankar, J. M. Thomas, Nature 1995,
378, 159.
[24] P. T. Tanev, M. Chibwe, T. J. Pinnavaia, Nature 1994,
368, 321.
[25] I. I. Slowing, B. G. Trewyn, S. Giri, V. Lin, Adv. Funct. Mater.
2007, 17, 1225.
[26] I. I. Slowing, J. L. Vivero-Escoto, C.-W. Wu, V. S.-Y. Lin, Adv.
Drug Delivery Rev. 2008, 60, 1278.
ORCID
Hossein Naeimi https://orcid.org/0000-0002-9627-596X
REFERENCES
[27] T. Wagner, T. Waitz, J. Roggenbuck, M. Fröba, C.-D. Kohl,
M. Tiemann, Thin Solid Films 2007, 515, 8360.
[28] A. Cabot, J. Arbiol, A. Cornet, J. R. Morante, F. Chen, M. Liu,
Thin Solid Films 2003, 436, 64.
[29] T. Yamada, H. Zhou, H. Uchida, M. Tomita, Y. Ueno,
T. Ichino, I. Honma, K. Asai, T. Katsube, Adv. Mater. 2002,
14, 812.
[30] X. Gao, S. Nie, J. Phys. Chem. B 2003, 107, 11575.
[31] R. M. Blanco, P. Terreros, M. Fernández-Pérez, C. Otero,
G. Díaz-González, J. Mol. Catal. B: Enzym. 2004, 30, 83.
[32] A. Schreiber, I. Ketelsen, G. H. Findenegg, Phys. Chem. Chem.
Phys. 2001, 3, 1185.
[1] M. Costa, T. A. Dias, A. Brito, F. Proenca, Eur. J. Med. Chem.
2016, 123, 487.
[2] H. Gourdeau, L. Leblond, B. Hamelin, C. Desputeau, K. Dong,
I. Kianicka, D. Custeau, C. Boudreau, L. Geerts, S.-X. Cai, Mol.
Cancer Ther. 2004, 3, 1375.
[3] S. A. Patil, J. Wang, X. S. Li, J. Chen, T. S. Jones, A. Hosni-
Ahmed, R. Patil, W. L. Seibel, W. Li, D. D. Miller, Bioorg. Med.
Chem. Lett. 2012, 22, 4458.
[4] A. A. Farag, S. N. Abd-Alrahman, G. F. Ahmed,
R. M. Ammar, Y. A. Ammar, S. Y. Abbas, Arch. Pharm.
(Weinheim). 2012, 345, 703.
[33] M. Golestanzadeh, H. Naeimi, ChemistrySelect 2019, 4, 1909.
[34] M. Golestanzadeh, H. Naeimi, RSC Adv. 2019, 9, 27560.
[35] M. Golestanzadeh, H. Naeimi, Z. Zahraie, ChemistrySelect
2016, 1, 6490.
[5] M. Kidwai, S. Saxena, M. K. R. Khan, S. S. Thukral, Bioorg.
Med. Chem. Lett. 2005, 15, 4295.
[6] M. M. Khafagy, A. H. F. A. El-Wahab, F. A. Eid, A. M. El-
Agrody, Farmacia 2002, 57, 715.
[36] M. Golestanzadeh, H. Naeimi, Z. Zahraie, Mater. Sci. Eng. C
2017, 71, 709.
[37] B. Maleki, S. Barat Nam Chalaki, S. S. Ashrafi, E. R. Seresht,
F. Moeinpour, A. Khojastehnezhad, R. Tayebee, Appl.
Organomet. Chem. 2015, 29, 290.
[38] B. Maleki, H. Eshghi, A. Khojastehnezhad, R. Tayebee,
S. S. Ashrafi, G. E. Kahoo, F. Moeinpour, RSC Adv. 2015, 5,
64850.
[39] S. Hemmati, P. Mohammadi, A. Sedrpoushan, B. Maleki, Org.
Prep. Proced. Int. 2018, 50, 465.
[40] M. Tarahomi, H. Alinezhad, B. Maleki, Appl. Organomet.
Chem. 2019, 29, e5203.
[41] M. Tarahomi, H. Alinezhad, B. Maleki, Appl. Organomet.
Chem. 2018, 116, 14.
[42] B. G. Toksha, S. E. Shirsath, S. M. Patange, K. M. Jadhav, Solid
State Commun. 2008, 147, 479.
[7] A. Parthiban, J. Muthukumaran, A. Manhas, K. Srivastava,
R. Krishna, H. S. P. Rao, Bioorg. Med. Chem. Lett. 2015, 25,
4657.
[8] O. S. Patrusheva, V. V. Zarubaev, A. A. Shtro,
Y. R. Orshanskaya, S. A. Boldyrev, I. V. Ilyina,
S. Y. Kurbakova, D. V. Korchagina, K. P. Volcho,
N. F. Salakhutdinov, Bioorg. Med. Chem. 2016, 24, 5158.
[9] K. Takao, H. Yahagi, Y. Uesawa, Y. Sugita, Bioorg. Chem.
2018, 77, 436.
[10] D. Kumar, V. B. Reddy, S. Sharad, U. Dube, S. Kapur, Eur.
J. Med. Chem. 2009, 44, 3805.
[11] M. G. Assy, M. M. Hassanien, S. A. Zaki, Pol. J. Chem. 1995,
69, 371.
[12] A. Afantitis, G. Melagraki, H. Sarimveis, P. A. Koutentis,
J. Markopoulos, O. Igglessi-Markopoulou, Bioorg. Med. Chem.
2006, 14, 6686.
[43] B. Atashkar, A. Rostami, B. Tahmasbi, Catal. Sci. Technol.
2013, 3, 2140.
[13] S. Khaksar, A. Rouhollahpour, S. M. Talesh, J. Fluorine Chem.
2012, 141, 11.

COFE2O4 NANOCOMPOSITE CATALYZED SYNTHESIS OF 4H-CHROMENES
11 of 11
[44] M. Hammouda, A. S. El-Ahl, Y. M. El-Toukhee,
M. A. Metwally, J. Chem. Res. 2002, 2002, 89.
How to cite this article: Mohammadi S,
Naeimi H. Functionalized CoFe2O4/lamellar
mesopore silica anchored to melamine
nanocomposite as a novel catalyst for synthesis of
4H-chromenes under mild conditions. Appl
Organometal Chem. 2020;e5630. https://doi.org/10.
1002/aoc.5630
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.