Immobilization of Lewis acidic ionic liquid on perlite nanoparticle surfaces as a highly efficient solid acid catalyst for the solvent-free synthesis of xanthene derivatives

Article abstract of DOI:10.1039/c9ra03312b

In this study, perlite nanoparticles were prepared through a simple method and then modified with Lewis acidic ionic liquid (perlite NP@IL/ZrCl₄) through a two step procedure. The prepared solid acid catalyst was characterized by Fourier transf

Full text of DOI:10.1039/c9ra03312b

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Immobilization of Lewis acidic ionic liquid on
perlite nanoparticle surfaces as a highly efficient
solid acid catalyst for the solvent-free synthesis of
xanthene derivatives
Cite this: RSC Adv., 2019, 9, 19940
*
L. Moradi
and M. Mirzaei
In this study, perlite nanoparticles were prepared through a simple method and then modified with Lewis
acidic ionic liquid (perlite NP@IL/ZrCl4) through a two step procedure. The prepared solid acid catalyst
was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy
(SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and thermo gravimetric
analysis (TGA). Perlite NP@IL/ZrCl4 was used as a new solid acid, reusable and green heterogeneous
nanocatalyst for the one-pot synthesis of xanthene derivatives. Synthesis of xanthenes was performed
under solvent free conditions using a catalytic amount (0.005 g, 0.4 mol%) of the prepared catalyst with
simple work-up and high to excellent yield of products. The reusability and high efficiency of this
catalyst makes this method attractive for large scale environment-friendly operations.
Received 3rd May 2019
Accepted 19th June 2019
DOI: 10.1039/c9ra03312b
rsc.li/rsc-advances
15%), Na2O (3–4%), K2O (3–5%), Fe2O3 (0.5–2%), MgO (0.2–
0.7%) and CaO (0.5–1.5%).39,40 Because of its low density and
Introduction
relatively low price, many commercial applications for perlite
have been developed in the construction and manufacturing
elds. It is used in lightweight plasters, concrete, insulation and
ceiling tiles.41 In horticulture, perlite can be used as a soil
amendment or alone as a medium for hydroponics or starting
cuttings.42 Small quantities of perlite are also used in foundries,
cryogenic insulation and in ceramics as a clay additive. It is also
used by the explosives industry.42 It was found to be an excellent
support for immobilization of catalysts and biocatalysts such as
enzymes for bioremediation and sensing applications.24,43,44 To
avoid of using the toxic organic solvents and due to the
advantages of multicomponent reactions including low
response time, high efficiency, clean work-up and easy puri-
cation, we have designed environmentally benign procedures
for the one-pot synthesis of xanthene and naphthopyranopyr-
imidine derivatives under thermal and solvent free conditions
using perlite NPS@IL/ZrCl4 as a new efficient and reusable solid
acid catalyst (Scheme 1).
Xanthene and its derivatives are pharmaceutically and biologi-
cally active compounds.1,2 Because of the widespread use of this
class of heterocyclic compounds in the preparation of dyes,3
laser technologies4 and pH-sensitive uorescent materials for
visualization of biomolecules,5 they have received signicant
attention in recent years. On the other hand, fused pyran ring
systems especially pyranopyrimidines have biological activities
including antimicrobial,6 anticonvulsant,7 antiplatelet,8 anti-
bacterial,9 antiphlogistic,10 analgesic,11 anti-inammatory,11
antigenotoxic12 and antifungal activities.7,13–15 These unique
properties, led to intensive research on the synthesis of
xanthene and naphthopyranopyrimidine derivatives in the
presence of various catalysts such as CoPy2Cl2,16 I2,17 choline
chloride,18 Y(NO3)3$6H2O and SnCl2$2H2O,19 ZnO NPs,20
Al(HSO4)3,21 sulfamic acid,22 perlite-SO3H,23 LiBr,24 silica
sulfuric acid,25 (nBu)4NBr,26 TfOH,27 cellulose sulfamic acid,28
molecular iodine,29 heteropolyacid,30 phosphoric acid sup-
ported on alumina,31 [IMPS][TfO],32 [HNMP][HSO4],33 [TEBSA]
[HSO4],34 [MIMPS][HSO4],35 [DMEA][HSO4],36 [BDMAP][OH]37
and sulfonyl-functionalized acidic ionic liquids.38 In recent
years, the application of supported catalysts was developed for
the synthesis of organic compounds. In this way, using low cost
and readily available supports has been considered for the
preparation of this class of heterogeneous catalysts. Perlite is an
amorphous volcanic glass containing SiO2 (70–75%), Al2O3 (12–
Results and discussion
FT-IR spectra of perlite nanoparticles and perlite NPs@IL/ZrCl4
were presented in Fig. 1 to prove the catalyst structure. FTIR of
perlite nanoparticles (Fig. 1a), shows the broad band at
3438.09 cmꢀ1, correspond to O–H vibrations. Bands at 1013.52
and 789.08 cmꢀ1 related to unsymmetrical and symmetrical Si–
O–Si vibrations, respectively. The Si–O vibrations on perlite
nanoparticles were appeared at 458.35 cmꢀ1. In FTIR spectrum
Department of Organic Chemistry, Faculty of Chemisry, University of Kashan, P. O. Box
8731753153, Kashan, Iran. E-mail: L_moradi@kashanu.ac.ir
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ꢁ
200 C was only 5%. This can be attributed to the removal of
moisture from nanoparticle surfaces. A weight loss about 21%
in the range of 300 to 350 ꢁC is related to the separation of ionic
liquid from the surface of catalyst. Finally, by removing the
hydroxyl groups from perlite nanoparticle surfaces, a weight
loss about 4% in the range of 480 to 520 ꢁC is observed. Ob-
tained results from TGA graph conrmed the chemical attach-
ment of organic groups to the perlite NPs surfaces.
X-ray diffraction analysis was used for investigating the
structure of perlite nanoparticles and perlite NPs@IL/ZrCl4. The
obtained diffractograms are displayed in Fig. 3. As shown in this
Figure, XRD patterns of primary and modied perlite nano-
particles exhibit the same characteristic peaks which shows that
the peaks and relative intensities match well with the X-ray
diffraction pattern of amorphous particles and the structure
of the primary perlite NPS preserved in the prepared catalyst.
These graphs also show that the presence of organic species has
no effect on the structure of perlite NPs. The peaks related to
ZrCl4 are recorded at 2q ¼ 30, 33, 50.5 and 60ꢁ. In the XRD
pattern of perlite NPs@IL/ZrCl4, the peaks of 2q ¼ 33 and 50.5ꢁ
are distinguishable and two other peaks are covered by other
broad peaks.
Scheme 1 Solvent free one-pot synthesis of three types of xanthene
derivatives in the presence of perlite NPs@IL/ZrCl4.
The scanning electron microscope (SEM) images of the
perlite NPs and perlite NPs@IL/ZrCl4 were displayed in Fig. 4(a
and b). These images clearly show the nanosize structure of
perlite NPs and modied sample. As can be seen from Fig. 4b,
the morphology of the perlite NPs@IL/ZrCl4 was quite similar to
the raw nanoparticles and there are no changes in nanoparticle
morphology aer modication process.
The composition of perlite nanoparticles and synthesized
catalyst was investigated by energy-dispersive X-ray spectros-
copy (EDX). Results clearly conrmed the existence of Zr, Cl
and N elements in the prepared catalyst structure (Fig. 5) and
consequently proved that ionic liquid and ZrCl4 were attached
successfully to the perlite nanoparticle surfaces.
As can be seen, the Zr and N content was 6.9% and 2.5%
respectively. It concluded that the percentage of ionic liquid
immobilized on perlite surfaces was about 1.25%. Further
amount of Zr demonstrated the chelating of Zr to OH groups
Fig. 1 FT-IR spectra of (a) perlite NPs and (b) perlite NPs@IL/ZrCl4.
of perlite NPs@IL/ZrCl4, the band at 3431.12 cmꢀ1 corresponds
to O–H vibrations and stretching vibrations of ]CH appeared
at 3094.10 cmꢀ1. Also the bands at 2946.25 and 2847.47 cmꢀ1
are from –CH bond vibrations. Moreover, two bands at 1584.14
and 1474.53 cmꢀ1 were existed from C]N and C]C vibrations,
respectively. Stretching vibrations at 1023.15 and 821.28 cmꢀ1
are related to unsymmetrical and symmetrical Si–O–Si vibra-
tions. Finally, the Si–O absorbance recorded at 457.58 cmꢀ1
.
TGA curve of perlite NPs@IL/ZrCl4 at the range of 25 to
800 ꢁC is shown in Fig. 2. The weight loss at the range of 100 to
Fig. 3 X-ray diffraction (XRD) pattern of (a) perlite and (b) perlite-IL/
Fig. 2 TGA analysis of perlite NPs IL/ZrCl4.
ZrCl4 nanoparticles.
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Fig. 4 SEM photographs of (a) perlite NPs and (b) perlite NPs@IL/ZrCl4
nanoparticles.
Fig. 5 EDX of perlite NPs (a) and perlite NPS@IL/ZrCl4 (b).
existed on the perlite surfaces (addition to be as zwitterion for
imidazolium ion). Furthermore, the mol% of catalyst based on
Zr ration was about 0.4 mol%.
to products with higher yields aer shorter times. Also in case of
aldehydes with electron donating groups, it was observed that
yield of reaction was lower aer longer times.
Aer the preparation and characterization of catalyst, reac-
tion conditions including the amount of catalyst and tempera-
ture were optimized. Firstly, optimum amount of catalyst was
determined using the reaction between dimedone (2 mmol) and
3-nitrobenzaldehyde (1 mmol) in the presence of various
Further study was done using the reaction of tereph-
thaldehyde with 2 mmol of dimedone (2) and 2 mmol of 2-
naphthol (3) for the preparation of 4e. Symmetric dimer product
was prepared with the reaction of terephthaldehyde with
4 mmol of dimedone (2) for preparation of 5e (Scheme 2). The
ꢁ
amounts of catalyst at 80 C. Results in Table 1 show that the
best yield of product was obtained in the presence of 0.005 g
(0.4 mol%) of catalyst (entry 2); also when the reaction was
carried out in the absence of catalyst, the yield of product was
only 5% aer 100 min (entry 5).
Table 1 Effects of catalyst amounts on yield of 5aa
For evaluation the temperature effect on the yield of product,
the model reaction was done in the presence of 0.005 g
(0.4 mol%) of catalyst at different temperatures (Table 2). Ob-
ꢁ
tained results show that 80 C was the best temperature (entry
ꢁ
3). Furthermore, the yield of product at 100 C was decreased
due to decomposition of products aer 100 min (entry 5).
Aer the determination of optimized conditions, appraisal
of the catalyst efficiency was estimated using the reaction of
a variety of aryl aldehydes, 2-naphthol and 1,3-dicarbonyl
compounds such as dimedone and barbituric acid for prepa-
ration of xanthene derivatives in the presence of catalytic
amount of perlite NPs@IL/ZrCl4. Obtained results in Table 3
show that aldehydes bearing electron withdrawing groups lead
Entry
Catalyst (g)
Time (min)
Yield (%)
1
2
3
4
5
0.003
0.005
0.008
0.01
—
140
100
100
85
85
92
92
92
5
100
a
Isolated yield.
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Table 2 Optimization of reaction temperaturea
ꢁ
(0.4 mol%) of perlite-NPs@IL/ZrCl4 at 80 C in the absence of
solvent (Entry 6, 18 and 27). Catalyst amount in presented
method is less than most of catalysts depicted in Table 4
demonstrated the high efficiency of solid acid catalyst.
Entry
T (ꢁC)
Time (min)
Yield (%)
1
2
3
4
5
60
70
80
90
100
180
130
100
100
100
58
75
92
92
88
On the other hand, in most reaction conditions (16 cases) the
temperature is higher than 80 C (applied temperature in pre-
ꢁ
sented method) and the yield of products is lower. As a result,
Lewis acidic ionic liquid supported catalyst is more active than
others in term of time, catalyst amount and temperature. In
fact, Zr atoms (as Lewis acid sites) loaded in catalyst surfaces,
can be activated the reactants (as shown in reaction mecha-
nism) and catalyzed the solvent-free synthesis of xanthenes.
Results collected in Table 4 shown that prepared catalyst
improved the yield of products compare with other catalysts.
Furthermore, easy available and very low cost material of
catalyst support (perlite), facile procedure for preparation of
perlite nanoparticles as well as easy functionalization process,
reusability and easy work up are some of the advantageous of
proposed method. As can be seen in Table 4, most of catalysts
are expensive, homogeneous, toxic and without facile
availability.
a
Dimedone (2 mmol), 3-nitrobenzaldehyde (1 mmol) in the presence of
0.005 g (0.4 mol%) of catalyst.
Table 3 One pot synthesis of xanthene derivatives in the presence of
perlite NPs@IL/ZrCl4 at 80 ꢁC under solvent free conditions
Entry
R
Product Time (min) Yield (%) MP (ꢁC)
1
2
3
4-CH3
4-OH
4-OCH3 4c
4a
4b
110
120
115
113
120
100
115
120
112
120
115
113
90
91
89
88
91
91
92
89
89
91
91
91
88
94
88
83
90
92
206–208 (ref. 45)
215–217 (ref. 45)
204–206 (ref. 45)
178–180 (ref. 45)
306–308 (ref. 45)
171–173 (ref. 45)
245–247 (ref. 45)
240–242 (ref. 45)
225–227 (ref. 45)
228–230 (ref. 20)
286–288 (ref. 46)
263–265 (ref. 46)
286–288 (ref. 46)
195–197 (ref. 46)
292–294 (ref. 46)
288–290 (ref. 47)
283–285 (ref. 48)
4
2-Cl
4d
4e
5a
5b
5c
5d
5e
7a
7b
7c
7d
5a
6
4-CHO
3-NO2
2,4-Cl2
4-CH3
2-Cl
4-CHO
4-OH
2,4-Cl2
4-NO2
4-CH3
7
8
9
Consequently, presented method has proved to be very
effective, green, eco-friendly, safe and easy to operate and also
the scale up of this method is easy.
10b
11
12
13
14
15
16
17
Suggested mechanism for the synthesis of xanthene deriva-
tives is shown in Scheme 3. As can be seen, in the initial step,
Lewis acidic ionic liquid catalyzed the conversion of keto to enol
form of 1,3 dicarbonyl; on the other hand, catalyst activated the
carbonyl group of aldehyde and the nucleophilic addition of 1,3
dicarbonyl compound to activated aldehyde lead to formation
of (I). Removal of H2O and nucleophilic addition of second mole
of 1,3 dicarbonyl compound to I, created the intermediate II.
Finally, cyclization and H2O removal from (II), give subsequent
xanthene.
130
133
120
105
4-OCH3 7e
2-OH 7f
3-OCH3 7g
a
b
2 (2 mmol), 3 (2 mmol), terephthaldehyde (1 mmol). Dimedone (4
mmol), aryl aldehyde (1 mmol).
One of the outstanding advantages of the catalysts is their
reusability and stability which makes them valuable for
commercial applications. Study on the reusability of prepared
catalyst was done using model reaction. Aer completion of the
reaction, the catalyst was separated. The recovered catalyst was
washed with chloroform (3 ꢂ 5 ml) and dried to use for the next
run in current reaction under equal conditions. It was found
that the catalyst could be reused for four times without
considerable loss of its activity (Fig. 6).
yield of products was excellent and the spectroscopic data of
these products demonstrated the structure of prepared
compounds.
In continue, the efficiency of prepared catalyst was compared
with some of other reported catalyst applied for the synthesis of
4c, 5a and 7c (as examples of three types of synthesized
xanthene derivatives). The results are summarized in Table 4. As
shown in this table, best yields were obtained using 0.005 g
The characterization of recovered catalyst by FTIR and SEM
methods was shown in Fig. 7. As can be seen, no changes were
occurred on morphology and particle size of recycled catalyst;
also, the main peaks are identical in both of the fresh and
recycled catalyst. Consequently, the prepared catalyst has high
stability and high efficiency in solvent-free synthesis of
xanthenes.
Experimental
Materials and apparatus
Chemicals such as dimedone, N,N-dimethylbarbituric acid, alde-
hyde derivatives, 2-naphthol, methyl imidazole, perlite nano-
particles, chloropropyltriethoxysilane, zirconium tetrachloride,
Scheme 2 Preparation of dimeric xanthenes.
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Table
4 Compression between the efficiency of perlite-NPs@IL/ZrCl4 and some of other catalysts in synthesis of xanthenes and
naphthopyranopyrimidinesa
Entry
Catalyst
Time
Yield (%)
T (ꢁC)
Ref.
1
2
3
4
5
6
7
8
[n-Pr2NH2][HSO4] (50 mol%)
BBSICb (2 ml)
P2O5 (20 mol%)
15 min
10 min
55 min
45 min
40 min
115 min
9.5 h
3 h
1 h
4 h
12 h
5 min
20 min
25 min
40 min
15 min
100 min
40 min,
25 min
24 min
50 min
55 min
25 min
80 min
1.5 h
82
80
71
76
78
88
91
87
87
80
75
88
88
92
97
87
92
80
85
90
87
86
78
58
94
94
80
50
120
120
110
80
110
80
rt
100
125
105
110
75
49
50
51
51
45
—
52
53
54
55
56
57
45
58
59
60
—
61
48
62
31
63
51
51
64
—
InCl3 (30 mol%)
TCCAc (5 mol%)
Perlite@Il/ZrCl4 (0.005 g, 0.4 mol%)
Cu(NO3)2, 3H2O (10 mol%)
[BMIM]HSO4 (0.1 g)
[CMMIM]Cl, sonication (0.2 g)
Co(HSO4)2 (0.025 g)
Naon-H (0.485 g)
Choline peroxydisulfate (2 mmol)
TCCA (5 mol%)
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
TMGTd (50 mmol)/TFA (60 mmol)
[Et3N–SO3H]Cl (15 mol%)
[Bmim][BF4]/Mg(BF4)2 (1 ml/0.5 mol%)
Perlite NPs@IL/ZrCl4 (0.005 g, 0.4 mol%)
Al(H2PO4)3 (0.1 g)
ZrOCl2/nano TiO2 (3 mol%)
Heteropolyacid (5 mol%)
H3PO4/Al2O3 (0.1 g/50% w/w)
I2 (10 mol%)
InCl3 (35 mol%)
P2O5 (20 mol%)
SiO2@HClO4 (3 mol%)
Perlite@IL/ZrCl4 (0.005 g, 0.4 mol%)
80
80
80
110
100
100
120
120
120
120
125
80
90 min
a
Entries 1–6 for solvent free preparation of 4c, 7–17 for preparation of 5a and 18–26 for 7c. b 1,10-Butylenebis(3-sulfo-3H-imidazol-1-ium) chloride.
Trichloroisocyanuric acid. d 1,1,3,3-N,N,N0,N0-Tetramethylguanidinium triuoroacetate.
c
Fig. 6 Reusability of perlite NPs@Il/ZrCl4.
Scheme
3 Suggested mechanism for the one-pot synthesis of
xanthene derivatives in the presence of perlite NPs@IL/ZrCl4
nanoparticles.
obtained from a STA503 analyzer. XRD patterns were collected on
a Philips Xpert MPD diffractometer equipped with a Cu Ka anode
ꢁ
˚
(l ¼ 1.54 A) in the 2q range from 10 to 80 . Morphology of perlite
NPs and catalyst, were analyzed by SEM using a MIRA/TESCAN
with accelerating voltage of 120 kV.
methanol, organic solvents and hydrochloric acid were purchased
from Fluka, Merck and Aldrich chemical companies. All of prod-
1
ucts were characterized by their spectral data. H NMR spectra
were recorded on a Avance BRUKER (DRX – 400 MHz) in CDCl3 or
DMSO-d6 as solvent. FTIR spectra were determined on a Nicolet
Magna series FTIR 550 spectrometer using KBr pellets. Thin layer
chromatography (TLC) on commercial aluminium-backed plates
of silica gel 60 F254 was used to monitor the progress of the reac-
tions. Thermo gravimetric curve of perlite NPs@IL/ZrCl4 were
Preparation of perlite nanoparticles
To make perlite from a crystalline to nanosize structure, 5 g of
perlite was heated in 500 ꢁC for 1 hour. Then HCl (150 ml, 2 M)
was added and reuxed for 24 hours. Aer that, the mixture was
ltered, washed and pH was controlled to neutralize. Finally,
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prepared catalyst was dried at 80 ꢁC and characterized by FT-IR,
XRD, SEM, EDX and TGA techniques (Scheme 2).
General procedure for the preparation of xanthene derivatives
In order to achieve satisfactory results, in a general procedure,
a mixture of 1 mmol benzaldehyde derivative, 2 mmol dime-
done or (1 mmol 2-naphthol and 1 mmol dimedone) in the
presence of optimized amount of perlite@IL/ZrCl4 nano-
particles (0.005 g, 0.4 mol%) was stirred for adequate times
ꢁ
under conventional heating conditions at 80 C. Aer comple-
tion of the reaction, the mixture was resolved in hot ethanol and
catalyst was separated by simple ltration. The crude product
was obtained aer evaporation and for further purication,
recrystallized from ethanol. In case of naphthopyranopyr-
imidines, a mixture of 1 mmol benzaldehyde derivative, 1 mmol
dimedone and 1 mmol N,N-dimethylbarbituric acid was stirred
in the presence of 0.005 g, (0.4 mol%) of catalyst at 80 ꢁC.
Separation and purication of reaction products was done
according to xanthene route.
Fig. 7 FTIR (a) and SEM image (b) of recovered catalyst.
Spectral data
9,9-Dimethyl-12-(4-methylphenyl)-8,9,10,12-tetrahydrobenzo[a]
xanthene-11-one (4a). White solid. Mp: 205–207 ꢁC. ꢀnmax (KBr)/
cmꢀ1: 3015 (]C–H), 2958 (–C–H), 1667 (C]O), 1596–1417 (C]C),
1374 (CH3, bending), 1300–1000 (C–O), 831 (]C–H bending OOP of
para disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: dH ¼ 8.01
(1H, d, 3JHH ¼ 7.6 Hz, Ar–H), 7.49 (2H, d, 3JHH ¼ 8.4 Hz, Ar–H), 7.55–
7.42 (3H, m, Ar–H), 7.15 (2H, d, 3JHH ¼ 8.0 Hz, Ar–H), 6.96 (2H, d,
3JHH ¼ 8.0 Hz, Ar–H), 5.50 (1H, s, CH), 2.56 (2H, d, 2JHH ¼ 17.6 Hz,
CH2C]O), 2.32 (2H, d, 2JHH ¼ 16.4 Hz, CH2), 2.12 (3H, s, CH3), 1.05
(3H, s, CH3), 0.88 (3H, s, CH3).
ꢁ
the precipitate was dried in 100 C for 4 hours and then calci-
nated in 700 ꢁC for 2 hours23 (Scheme 4).
Preparation of perlite NPs@IL/ZrCl4
In rst step for preparation of catalyst, 1-(3-triethoxysilyl)-
propyl-3-methylimidazolium chloride (Si[pmim]Cl) was
synthesized according to Kumar method.65 A mixture of methyl
imidazole (1 mmol) and 3-chloropropyltriethoxysilane (1 mmol)
was reuxed in 5 ml anhydrous toluene for 2 hours under N2
atmosphere. Aer the reaction time, obtained viscous ionic
liquid was extracted by diethyl ether. In order to attach the ionic
liquid to perlite nanoparticle surfaces, 1 g of perlite nano-
particles was added to 0.6 g of Si[pmim]Cl and stirred for 16
hours at 90 ꢁC. Aer the time, the mixture was washed with
10 ml of boiling dichloromethane and dried. Then, 0.7 g ZrCl4
dissolved in anhydrous toluene was added to obtained precip-
itate and stirred at room temperature for 12 hours. Finally,
9,9-Dimethyl-12-(4-hydroxyphenyl)-8,9,10,12-tetrahydrobenzo[a]
xanthene-11-one (4b). Pale yellow solid. Mp: 215–217 ꢁC. ꢀnmax (KBr)/
cmꢀ1: 3309 (O–H), 3050 (]C–H), 1717 (C]O), 1642–1400 (C]C),
1366 (CH3, bending), 1251 (Ar–O), 1300–1000 (C–O), 850 (]C–H
bending OOP of para disubstituted phenyl ring). 1H NMR (DMSO-
d6)/ppm: dH ¼ 9.20 (1H, s, OH), 8.12 (1H, d, 3JHH ¼ 9.2 Hz, Ar–H),
7.88 (2H, t, 3JHH ¼ 9.2 Hz, Ar–H), 7.44–7.32 (3H, m, Ar–H), 7.26 (2H,
3
3
d, JHH ¼ 8.0 Hz, Ar–H), 6.65 (2H, d, JHH ¼ 8.0 Hz, Ar–H), 5.63
(1H, s, CH), 2.67 (2H, d, 2JHH ¼ 16.4 Hz, CH2C]O), 2.32 (1H, d, 2JHH
¼ 16.0 Hz, CH2), 2.10 (1H, d, 2JHH ¼ 16.0 Hz, CH2), 1.05 (3H, s, CH3),
0.88 (3H, s, CH3).
9,9-Dimethyl-12-(4-methoxyphenyl)-8,9,10,12-tetrahydrobenzo[a]
xanthene-11-one (4c). White solid. Mp: 204–206 ꢁC. ꢀnmax (KBr)/
cmꢀ1: 3015 (]C–H), 2955 (–C–H), 1648 (C]O), 1597–1462 (C]C),
1377 (CH3, bending), 1300–1000 (C–O), 831 (]C–H bending OOP of
para disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: dH ¼ 8.05
(1H, d, 3JHH ¼ 7.6 Hz, Ar–H), 7.95 (2H, d, 3JHH ¼ 8.4 Hz, Ar–H), 7.48–
7.38 (3H, m, Ar–H), 7.15 (2H, d, 3JHH ¼ 8.0 Hz, Ar–H), 6.72 (2H, d,
3JHH ¼ 8.0 Hz, Ar–H), 5.50 (1H, s, CH), 3.61 (3H, s, OCH3), 2.46 (2H,
d, 2JHH ¼ 17.6 Hz, CH2C]O), 2.36 (1H, d, 2JHH ¼ 16.4 Hz, CH2), 2.15
(1H, d, 2JHH ¼ 16.4 Hz, CH2), 1.05 (3H, s, CH3), 0.90 (3H, s, CH3).
9,9-Dimethyl-12-(2-chlorophenyl)-8,9,10,12-tetrahydrobenzo
[a]xanthene-11-one (4d). White solid. Mp: 178–180 ꢁC. ꢀnmax
(KBr)/cmꢀ1: 3061 (]C–H), 2956 (–C–H), 1670 (C]O), 1622–
1469 (C]C), 1373 (CH3, bending), 1300–1000 (C–O), 741 (]C–H
Scheme 4 Preparation of perlite NPs@IL/ZrCl4.
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2
2
bending OOP of ortho disubstituted phenyl ring). 1H NMR d, JHH ¼ 16.0 Hz, CH2), 2.06 (4H, d, JHH ¼ 16.0 Hz, CH2),
3
(DMSO-d6)/ppm: dH ¼ 8.12 (1H, t, JHH ¼ 8.0 Hz, Ar–H), 7.90 1.02 (12H, s, CH3), 0.88 (12H, s, CH3).
3
(2H, d, JHH ¼ 8.0 Hz, Ar–H), 7.67–7.00 (7H, m, Ar–H), 5.78
12-(4-Hydroxyphenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo
(1H, s, CH), 2.68–2.67 (4H, m, CH2C]O and CH2), 1.05 (3H, s, [5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7a). Cream
CH3), 0.88 (3H, s, CH3).
solid. Mp: 286–288 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3206 (O–H), 3053 (]C–
4-(9,9-Dimethyl-11-oxo-8,10,11,12-tetrahydro-9H-benzo[a] H), 2926 (–C–H), 1669 (C]O), 1541–1417 (C]C), 1356 (CH3,
xanthene-12-yl)-benzaldehyde (4e). White yellow solid. Mp: bending), 1300–1000 (C–O), 855 (]C–H bending OOP of para
306–308 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3058 (]C–H), 2958 (–C–H), disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: dH ¼ 8.90
1670 (C]O), 1595–1451 (C]C), 1367 (CH3, bending), 1300– (1H, s, OH), 8.30 (2H, d, 3JHH ¼ 8.0 Hz, Ar–H), 8.03–7.85 (3H, m,
1000 (C–O). 1H NMR (DMSO-d6)/ppm: dH ¼ 8.05–7.90 (3H, m, Ar–H), 7.53–7.43 (3H, m, Ar–H), 6.95 (2H, d, 3JHH ¼ 8.0 Hz, Ar–
Ar–H), 7.60–7.45 (3H, m, Ar–H), 7.05 (2H, s, Ar–H), 5.58 H), 5.98 (1H, s, CH), 3.33 (3H, s, CH3), 3.19 (3H, s, CH3).
(1H, s, CH), 2.54–2.00 (4H, m, CH2C]O and CH2), 1.00 (3H, s,
CH3), 0.75 (3H, s, CH3).
12-(2,4-Dichlorophenyl)-8,10-dimethyl-8,10-dihydro-9H-
benzo[5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7b).
White solid. Mp: 263–265 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3058 (]C–H),
9-(3-Nitrophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-
ꢁ
1H-xanthene-1,8-(2H)-dione (5a). White solid. Mp: 171–173 C. 2952 (–C–H), 1707 (C]O), 1661–1456 (C]C), 1355 (CH3,
ꢀnmax (KBr)/cmꢀ1: 3063 (]C–H), 2961 (–C–H), 1662 (C]O), 1623– bending), 1300–1000 (C–O). 1H NMR (DMSO-d6)/ppm: dH
¼
1429 (C]C), 1355 and 1529 (N]O), 1355 (CH3, bending), 1300– 7.55–7.42 (4H, m, Ar–H), 7.31 (1H, s, Ar–H), 7.12 (1H, d, 3JHH
1
1000 (C–O). H NMR (DMSO-d6)/ppm: dH ¼ 7.98–7.97 (2H, m, ¼ 9.6 Hz, Ar–H), 6.90–6.65 (3H, m, Ar–H), 5.77 (1H, s, CH),
3
3
Ar–H), 7.64 (1H, d, JHH ¼ 8.0 Hz, Ar–H), 7.55 (1H, t, JHH
¼
3.50 (3H, s, CH3), 3.20 (3H, s, CH3).
8.0 Hz, Ar–H), 4.65 (1H, s, CH), 2.58–2.48 (4H, m, CH2C]O),
12-(4-Nitrophenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo
2
2
2.27 (2H, d, JHH ¼ 16.0 Hz, CH2), 2.10 (2H, d, JHH ¼ 16.0 Hz, [5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione
(7c).
CH2), 1.03 (6H, s, CH3), 0.89 (6H, s, CH3).
Cream solid. Mp: 286–288 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3090 (]C–
9-(2,4-Dichlorophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro- H), 2850 (–C–H), 1753 (C]O), 1674–1441 (C]C), 1575 and
1H-xanthene-1,8-(2H)-dione (5b). White solid. Mp: 245–247 ꢁC. ꢀnmax 1342 (N]O), 1342 (CH3, bending), 1300–1000 (C–O), 836 (]
(KBr)/cmꢀ1: 3070 (]C–H), 2962 (–C–H), 1661 (C]O), 1623–1424 C–H bending OOP of para disubstituted phenyl ring). 1H
(C]C), 1359 (CH3, bending), 1300–1000 (C–O). 1H NMR (DMSO-d6)/ NMR (DMSO-d6)/ppm: dH ¼ 8.05–7.90 (5H, m, Ar–H), 7.68–
ppm: dH ¼ 7.40 (1H, s, Ar–H), 7.28 (2H, m, Ar–H), 4.75 (1H, s, CH), 7.63 (2H, m, Ar–H), 7.55–7.44 (3H, m, Ar–H), 5.83 (1H, s,
2.57 (2H, d, 2JHH ¼ 18.4 Hz, CH2C]O), 2.46 (2H, d, 2JHH ¼ 18.4 Hz, CH), 3.49 (3H, s, CH3), 3.13 (3H, s, CH3).
2
CH2C]O), 2.27 (2H, d, 2JHH ¼ 16.0 Hz, CH2), 2.05 (2H, d, JHH
¼
12-(4-Methylphenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo[5,6]
chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7d). White solid. Mp:
195–197 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3015 (]C–H), 2952 (–C–H), 1709 (C]
16.0 Hz, CH2), 1.02 (6H, s, CH3), 0.90 (6H, s, CH3).
9-(3-Methoxyphenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahy-
dro-1H-xanthene-1,8-(2H)-dione (5c). White solid. Mp: 240– O), 1630–1452 (C]C), 1399 (CH3, bending), 1300–1000 (C–O), 808
1
242 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3050 (]C–H), 2958 (–C–H), 1662 (C] (]C–H bending OOP of para disubstituted phenyl ring). H NMR
O), 1592–1489 (C]C), 1370 (CH3, bending), 1300–1000 (C–O), (DMSO-d6)/ppm: dH ¼ 8.03–7.90 (3H, m, Ar–H), 7.59 (1H, t, 3JHH
¼
824 (]C–H bending OOP of para disubstituted phenyl ring). 1H 8.0 Hz, Ar–H), 7.56–7.48 (2H, m, Ar–H), 7.19 (2H, d, 3JHH ¼ 6.8 Hz,
3
3
NMR (DMSO-d6)/ppm: dH ¼ 7.04 (2H, d, JHH ¼ 6.4 Hz, Ar–H), Ar–H), 6.97 (2H, d, JHH ¼ 6.8 Hz, Ar–H), 5.60 (1H, s, CH), 3.49
6.75 (2H, d, 3JHH ¼ 7.2 Hz, Ar–H), 4.45 (1H, s, CH), 3.66 (3H, s, (3H, s, CH3), 3.14 (3H, s, CH3), 2.12 (3H, s, CH3).
2
OCH3), 2.69–2.63 (4H, m, CH2C]O), 2.23 (2H, d, JHH
¼
12-(4-Methoxyphenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo
2
16.0 Hz, CH2), 2.07 (2H, d, JHH ¼ 16.0 Hz, CH2), 1.02 (6H, s, [5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7e). Yellow
CH3), 0.88 (6H, s, CH3).
solid. Mp: 292–294 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3103 (]C–H), 2955 (–C–
9-(4-Chlorophenyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H- H), 1737 (C]O), 1665–1432 (C]C), 1362 (CH3, bending), 1300–
xanthene-1,8-(2H)-dione (5d). White solid. Mp: 225–227 ꢁC. ꢀnmax 1000 (C–O), 1267 and 1084 (Ar–C–O), 849 (]C–H bending OOP
(KBr)/cmꢀ1: 3050 (]C–H), 2957 (–C–H), 1663 (C]O), 1594–1485 of para disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: dH
(C]C), 1364 (CH3, bending), 1300–1000 (C–O), 742 (]C–H bending ¼ 8.05–7.67 (3H, m, Ar–H), 7.55–7.44 (4H, m, Ar–H), 7.20 (2H, d,
3
OOP of ortho disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: 3JHH ¼ 7.2 Hz, Ar–H), 6.67 (2H, d, JHH ¼ 7.2 Hz, Ar–H), 5.60
dH ¼ 7.26–7.12 (3H, m, Ar–H), 7.09 (1H, t, 3JHH ¼ 5.6 Hz, Ar–H), 4.80 (1H, s, CH), 3.49 (3H, s, CH3), 3.35 (3H, s, OCH3), 3.21 (3H, s,
(1H, s, CH), 2.62 (2H, d, 2JHH ¼ 17.6 Hz, CH2C]O), 2.48 (2H, d, 2JHH CH3).
¼ 17.6 Hz, CH2C]O), 2.24 (2H, d, 2JHH ¼ 16.4 Hz, CH2), 2.02 (2H, d,
2JHH ¼ 16.4 Hz, CH2), 1.02 (6H, s, CH3), 0.90 (6H, s, CH3).
4,40-Benzilidine-bis[3,3,6,6-tetramethyl-3,4,5,6,7,9-hex-
12-(2-Hydroxyphenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo
[5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7f). Cream
solid. Mp: 288–290 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3300 (O–H), 3052 (]C–
ahydro-1H-xanthene-1,8-(2H)-dione] (5e). White solid. Mp: H), 2962 (–C–H), 1700 (C]O), 1584–1400 (C]C), 1379 (CH3,
228–230 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3049 (]C–H), 2962 (–C–H), bending), 1300–1000 (C–O), 759 (]C–H bending OOP of ortho
1610 (C]O), 1584–1400 (C]C), 1389 (CH3, bending), 1300– disubstituted phenyl ring). 1H NMR (DMSO-d6)/ppm: dH ¼ 8.75
1000 (C–O), 828 (]C–H bending OOP of para disubstituted (1H, s, OH), 7.78–7.52 (3H, m, Ar–H), 7.32–6.85 (7H, m, Ar–H),
phenyl ring). 1H NMR (DMSO-d6)/ppm: dH ¼ 7.40 (4H, s, Ar– 5.83 (1H, s, CH), 3.49 (3H, s, CH3), 3.13 (3H, s, CH3).
H), 4.75 (2H, s, CH), 2.77–2.49 (8H, m, CH2C]O), 2.26 (4H,
12-(3-Methoxyphenyl)-8,10-dimethyl-8,10-dihydro-9H-benzo
[5,6]chromene[2,3,d]pyrimidine-9,11-(10H)-dione (7g). Yellow
19946 | RSC Adv., 2019, 9, 19940–19948
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solid. Mp: 283–285 ꢁC. ꢀnmax (KBr)/cmꢀ1: 3027 (]C–H), 2959 (–C– 12 F. Chabchoub, M. Messaad, H. Ben Mansour, L. Ghdira and
ˆ
H), 1671 (C]O), 1595–1451 (C]C), 1368 (CH3, bending), 1300–
M. Salem, Eur. J. Med. Chem., 2007, 42, 715.
13 M. M. Khafagy, A. H. F. Abd El-Wahab, F. A. Eid and A. M. El-
Agrody, IL Farmaco, 2002, 57, 715.
1
3
1000 (C–O). H NMR (DMSO-d6)/ppm: dH ¼ 7.65 (2H, t, JHH
¼
7.6 Hz, Ar–H), 7.55–7.42 (5H, m, Ar–H), 7.29–7.07 (3H, m, Ar–H),
ˆ
5.87 (1H, s, CH), 3.65 (3H, s, OCH3), 3.56 (3H, s, CH3), 3.12 14 M. Messaad, F. Chabchoub and M. Salem, Heterocycl.
(3H, s, CH3).
Commun., 2005, 9, 401.
15 O. Kodama, H. Ichikawa, T. Akatsuka, V. Santisopasri,
A. Kato and Y. Hayashi, J. Nat. Prod., 1993, 56, 292.
16 J. V. Mdhav, B. S. Kuram and B. Rajitha, ARKIVOC, 2008, ii,
204.
Conclusions
In this study, perlite nanoparticles was prepared and modied
with Lewis acidic ionic liquid (perlite NPs@IL/ZrCl4) and char- 17 B. Das, B. Ravikanth, R. Ramu, K. Laxminarayana and
acterized with FTIR, XRD, SEM, EDX and TGA techniques. We B. v. Rao, J. Mol. Catal. A: Chem., 2006, 255, 74.
presented a new efficient and environmental friendly pathway 18 P. Liu, H. Jian-Wu, S. J. Liang, G. L. Liang, J. Y. Wang and
for one pot synthesis of xanthene and naphthopyranopyr- Z.-H. Zhang, Monatsh. Chem., 2016, 147, 801.
imidine derivatives via multicomponent reactions using perlite 19 B. Karami, K. Eskandari, Z. Zare and S. Gholipour, Chem.
NPs@IL/ZrCl4 as a recyclable effective solid acid catalyst. This Heterocycl. Compd., 2014, 49, 1715.
simple procedure is solvent free and it's easy and clean work up, 20 J. Safaei-Ghomi and M. A. Ghasemzadeh, Chin. Chem. Lett.,
high yield of products and reusability of catalyst as well as low
2012, 23, 1225.
cost and very little amounts of catalyst (0.005 g, 0.4 mol%), 21 H. R. Shaterian, M. Ghashang and N. Mir, ARKIVOC, 2007, xv,
make this method considerable for the synthesis of other
organic compounds.
1.
22 B. Rajitha, B. S. Kumar, B. Y. T. Reddy and P. N. Reddy,
Tetrahedron Lett., 2005, 46, 8691.
23 E. Mirhadi, A. Ramazani, M. Rouhani and S. Woo Joo,
Chemija, 2013, 24, 320.
Conflicts of interest
There are no conicts to declare.
24 A. Saini, S. Kumar and J. S. Sandhu, Synlett, 2006, 12, 1928.
25 M. Seyyedhamzeh, P. Mirzaei and A. Bazgir, Dyes Pigm., 2008,
76, 836.
26 S. Kantevari, M. V. Chary, A. P. R. Das, S. V. N. Vuppalapati
and N. Lingaiah, Catal. Commun., 2008, 9, 1575.
27 T. Ohishi, T. Kojima, T. Matsuoka, M. Shiro and H. Kotsuki,
Tetrahedron Lett., 2001, 42, 2493.
Acknowledgements
We are thankful from University of Kashan for supporting this
study by Grant No. 784946.
28 R. Rao Chinta, V. Harikrishna, V. Kumar Tulam,
P. S. Mainkar and P. K. Dubey, Asian J. Chem., 2016, 28, 899.
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