Inclusion complex of Isatoic anhydride with β-cyclodextrin and supramolecular one-pot synthesis of 2, 3-dihydroquinazolin-4(1H)-ones in aqueous media

Article abstract of DOI:10.1007/s10847-012-0203-z

The inclusion complex of isatoic anhydride with β-cyclodextrin was formed as a result of intermolecular interaction between isatoic anhydride with β-CD. The inclusion complex was confirmed by IR spectroscopy, X-ray diffraction and DSC studies. From application of complex, herein we have described a simple and efficient protocol for synthesis of 2, 3-dihydroquinazoline-4(1H)-one derivatives by one pot condensation of isatoic anhydride, ammonium acetate or amine and aldehyde using β-CD as a supramolecular catalyst in aqueous media.

Full text of DOI:10.1007/s10847-012-0203-z

J Incl Phenom Macrocycl Chem
DOI 10.1007/s10847-012-0203-z
ORIGINAL ARTICLE
Inclusion complex of Isatoic anhydride with b-cyclodextrin
and supramolecular one-pot synthesis of 2, 3-dihydroquinazolin-
4(1H)-ones in aqueous media
•
•
•
Dipak R. Patil Pravin G. Ingole Kripal Singh
Dipak S. Dalal
Received: 4 January 2012 / Accepted: 8 June 2012
Ó Springer Science+Business Media B.V. 2012
Abstract The inclusion complex of isatoic anhydride
with b-cyclodextrin was formed as a result of intermolec-
ular interaction between isatoic anhydride with b-CD.
The inclusion complex was confirmed by IR spectroscopy,
X-ray diffraction and DSC studies. From application of
complex, herein we have described a simple and efficient
protocol for synthesis of 2, 3-dihydroquinazoline-4(1H)-
one derivatives by one pot condensation of isatoic anhy-
dride, ammonium acetate or amine and aldehyde using
b-CD as a supramolecular catalyst in aqueous media.
the binding forces involved in the inclusion complex for-
mation are Vander Waals interactions, hydrophobic inter-
actions between guest molecules and b-CD [3]. Because of
such behavior b-CD is used as catalyst for varieties of
organic reactions [4].
Isatoic anhydride is used for synthesis of racemic
paraensine [5], its reaction with amine and amides [6] and
in synthesis of diverse heterocycles [7]. 2,3-dihydroqui-
nazolinone derivatives are an important class of heterocy-
cles which shows a wide range of biological, antibiotic,
antipyretic, analgesic, diuretic, antihistamine, antidepres-
sant and vascodialating activities [8, 9]. The quinazolinone
moiety is a building block for various naturally occurring
alkaloids [10] such as glycosamine [11], luotonin [12] and
deoxyvasicinone [13]. In addition 2,3-dihydroquinazoli-
nones have been shown to act as potent tubulin inhibitors
with the impressive antiproliferatrive activity against sev-
eral human cancer cell lines [14].
Keywords b-Cyclodextrin ꢀ Isatoic anhydride ꢀ
Inclusion complex ꢀ IR spectroscopy ꢀ X-ray diffraction ꢀ
Differential scanning calorimetry
Introduction
Cyclodextrins are cyclic oligosaccharides possessing
hydrophobic cavity, which binds substrate selectively and
catalyze chemical reactions with high selectivity. They
catalyze reaction by supramolecular catalysis involving
reversible formation of host–guest complexes by non-
covalent bonding as seen in enzymes [1, 2]. b-cyclodextrin
is a cyclic heptamer composed of seven glucose units
jointed head to tail by a 1,4-links. It is widely accepted that
Recently a number of classical methods for synthesis of
2,3-dihydroquinazolin-4(1H)-one have been reported in
literature involving use of Ethylene diamine diacetate [15],
silica sulfuric acid [16], ionic liquid/water [17], p-TsOH
[18], KAl(SO4)2ꢀ12H2O [19], gallium triflate [20],
[bimm]BF4 [21], Montmorillonite K-10 [22], Al(H2PO4)3
[23], condensation of 2-aminobenzamides with aldehyde in
presence of p-TsOH/DDQ [24], CuCl2 [25], chiral phos-
phoric acid [26, 27], iodine [28], nano Fe3O4 [29], use
of p-toluenesulphonic acid-paraformaldehyde copolymer
[30], silica bonded N-propyl sulfamic acid [31], etc.
However most of the reported methods involve the use of
organic solvents, metal catalyst with tedious procedure and
low yields of product. Therefore the development of sim-
ple, environmentally benign, high yielding and clean syn-
thesis of 2,3-dihydroquinozolin-4(1H)-ones is demand.
Water is safe, economical and environmentally benign
D. R. Patil ꢀ D. S. Dalal (&)
Department of Organic Chemistry, North Maharashtra
University, Jalgaon 425 001, MS, India
e-mail: dsdalal2007@gmail.com
P. G. Ingole ꢀ K. Singh
Central Salt and Marine Chemicals Research Institute,
Council of Scientific and Industrial Research (CSIR),
Bhavnagar 364 021, Gujarat, India
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J Incl Phenom Macrocycl Chem
solvent [32]. In connection with our previous work with
cyclodextrin [33] and considering the application of
inclusion complex of isatoic anhydride with b-CD [34],
herein we have developed a simple methodology for for-
mation of 2, 3-dihydroquinazolin-4(1H)-ones in aqueous
media.
reaction refluxed with stirring for appropriate time till
reaction complete. The progress of reaction is monitored
with TLC by extracting reaction mass in ethyl acetate.
After completion of reaction, the reaction was cool and
extracted with dichloromethane (10 mL). The aqueous
layer washed thrice with dichloromethane (3 9 10 mL).
The collected organic layer dried with anhydrous Na2SO4,
evaporated in rotaevaporator leads to crude product which
purified by recrystalization in ethanol. To the aqueous layer
acetone added dropwise with stirring till white precipited
formed, cool at lower temperature, filtered, washed with
cold water and acetone, dried and recycled. All synthesized
Experimental
Material and chemicals
1
b-CD purchased from Aldrich, isatoic anhydride, ammo-
nium acetate, amines and aldehydes (analytical grade)
purchased from Spectrochem and were used without
purification.
compounds have been characterized by IR, H NMR, 13C
NMR and mass spectroscopy and compare with literature
data.
Methods and instruments
Result and discussion
IR spectra were recorded in frequency range from 4000 to
400 cm-1 with IR affinity model-I (Schimadzu) using KBr.
Powder X-ray diffraction patterns were obtained using a
Philips X’pert MPD System. Differential scanning calo-
rimetry (DSC) analyses were carried out in the temperature
range from 30 to 500 °C in a stream of nitrogen atmo-
sphere on DSC-50 thermal analyzer (Shimadzu, Japan).
During experiments, aluminium crucibles were used. The
heating rate was 10 °C/min, and the flow rate of nitrogen
The complex of isatoic anhydride and b-CD is studied by
various physical methods. The evidence for association of
isatoic anhydride and cyclodextrin provided by A. Kumar
1
and et al. [34] by H NMR spectroscopy in which there is
upfield shift of H-3 (0.034 ppm) and H-5 (0.058 ppm) of
cyclodextrin in complex as compared to uncomplex b-CD
indicating the formation of complex. Herein, we have
studied IR, XRD and DSC of complex.
1
atmosphere was 50 ml/min. Both H NMR and 13C NMR
Complex formation studied by IR spectroscopy
were recorded on a Bruker Avance- II spectrophotometer
operating at 500 MHz.
The formation of inclusion complex of b-CD and guest
substances is accompanied by changes in their IR spectra
as compared with individual components [35, 36]. Figure 1
shows the IR spectra of b-CD, isatoic anhydride, inclusion
complex and physical mixture in solid state. Significance
differences in CH and CO vibration modes were found.
Peaks are not only shifted after complex formation but
the shapes of peaks are also changed. The aliphatic
CH of cyclodextrin 2,926 cm-1 and in individual isatoic
anhydride 1,728.22 cm-1 shifted to 2,929.87 cm-1 and
1,730.15 cm-1 respectively. This is not observed in phys-
ical mixture suggesting an interaction between isatoic
anhydride and b-CD. The absorption band at 767.61 cm-1
of disubstituted benzene ring in individual isatoic anhy-
dride shifted to 765.74 cm-1 in inclusion complex, which
was unaffected in physical mixture indicating phenyl ring
interaction with b-CD.
Preparation of inclusion complex of isatoic anhydride
with b-CD
The complex between isatoic anhydride and b-CD is pre-
pared by coprecipitation method [35] from aqueous ethanol
solution. To the clear solution of b-CD (1 mmol) in 25 mL
of H2O, isatoic anhydride (1 mmol) previously dissolved in
ethanol added dropwise with stirring at room temperature
and the resulting mixture allow to stir for 12 h. The white
precipited obtained was filtered, washed gently with water
and dried.
General procedure for synthesis
of 2,3-dihydroquinazolin-4(1H)-one
To a stir solution of b-CD (1 mmol) in 10 mL of H2O,
isatoic anhydride (5 mmol) previously dissolved in ethanol
added dropwise and the resulting mixture was allowed to
stir for 15 min. Then ammonium acetate (6 mmol) or
amine (5 mmol) and aldehyde (5 mmol) (in case of solid
previously dissolved in ethanol) added dropwise and
Complex formation studied by powder X-ray analysis
True inclusion complexes have its diffraction pattern
altered from those of pure components [37]. The powder
X-ray pattern for individual components, complex and
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J Incl Phenom Macrocycl Chem
d
1728
767
765
c
2929
2926
1730
b
767
1728
a
Fig. 3 DSC of b Isatoic anhydride, c b-CD-isatoic anhydride complex
and d physical mixture
4000
3500
3000
2500
2000
1500
1000
500
0
cm-1
Complex formation studied by DSC
Fig. 1 FTIR of a b-CD, b Isatoic anhydride, c b-CD-isatoic
anhydride complex and d physical mixture
The DSC thermogram for isatoic anhydride, b-CD-isatoic
anhydride complex and physical mixture is represented in
Fig. 3. The thermogram of isatoic anhydride shows char-
acteristic endothermic peak at 237.75 °C corresponding to
its fussion peak. As regards with the analysis of b-CD-
isatoic anhydride complex, the peak of isatoic anhydride
found at 211.62 °C. Whereas in physical mixture, the peak
of isatoic anhydride was found at 221.35 °C with less
effect as compare to true inclusion complex clearly indi-
cating an interaction between b-CD and isatoic anhydride.
This lowering of melting of isatoic anhydride in complex
state is due to variation of intermolecular forces amongst
isatoic anhydride by b-CD. The second endothermic peak
in isatoic anhydride occurs at 374.41 °C related to its
decomposition. It disappears in ‘c’ and ‘d’ may be due to
alteration with b-CD. The endothermic peak of b-CD-
isatoic anhydride complex around 105-113 °C is associated
to crystal water losses from b-CD. Owing to the association
between isatoic anhydride and b-CD, the exothermic peak
of b-CD in complex shifted to higher temperature of
319.72 °C than in physical mixture occurs at 309.43 °C.
Alteration in these thermal properties due to intermolecular
interactions supports the formation of inclusion complex.
Water is safe, economical and environmentally benign
solvent; however the fundamental problem in with per-
forming reactions in water is that many organic substrates are
hydrophobic and insoluble in water. This difficulty is solved
by inclusion formation characteristic of b-CD that enhances
the solubility of guest molecule in water. By taking the
advantage of inclusion complex ability of b-CD with isatoic
anhydride we report the synthesis of 2,3-dihydroquinazolin-
4(1H)-ones from reaction of isatoic anhydride, ammo-
nium acetate or amine and aldehyde in aqueous media
(Scheme 1, 2). For optimizationthe reaction has been carried
d
c
b
a
0
20
40
60
80
2θ(deg.)
Fig. 2 Powder X-ray diffraction patterns of a b-CD, b Isatoic
anhydride, c b-CD-isatoic anhydride complex and d physical mixture
physical mixture is shown in Fig. 2. The diffraction pattern
of complex was found to be different than diffraction
pattern of pure b-CD and isatoic anhydride. Comparing the
pattern for b-CD-isatoic anhydride complex with that of
physical mixture reveals mark differences. In complex the
new peaks were found and shift in peak position also found
where as the physical mixture has the peaks which were
superimposition of two individuals. Besides, it is also
important to remarks that the peak intensities in complex
were decreased with respect to the spectrum of b-CD,
indicating the lower degree of crystallinity for the complex.
123

J Incl Phenom Macrocycl Chem
Scheme 1 b-CD catalyzed
synthesis of 2,3-
dihydroquinazolin-4(1H)-one
from isatoic anhydride,
ammonium acetate and
aldehyde
O
O
Beta- cyclodextrin
NH
R'
O
O
R' CHO
NH4OAc
+
+
+
H2O, reflux
N
H
N
H
O
O
One-pot
Scheme 2 b-CD catalyzed
synthesis of 2,3-
dihydroquinazolin-4(1H)-one
from isatoic anhydride, primary
amine and aldehyde
O
O
Beta- cyclodextrin
H2O, reflux
R
N
+
R NH2
R' CHO
N
H
R'
N
H
One-pot
Table 1 Formation of 2,3-dihydroquinazoline-4-one under different
reaction condition
Table 2 b-Cyclodextrin catalyzed one-pot synthesis of 2,3-dihydro-
quinazolinones in water
Entry b-CD (mmol) Solvent
Condition
Yield (%)a
Entry Ammonium
salt/amine (R)
R0
Time (h) Yield (%)a
1
–
H2O
Reflux, 6 h
Reflux, 2 h
Reflux, 2 h
60
82
86
1
NH4OAc
NH4OAc
NH4OAc
NH4OAc
NH4OAc
NH4OAc
NH4OAc
NH4OAc
C6H5
C6H5
2
86, 85b
85
2
0.1
0.2
0.4
0.6
0.8
1
H2O
2
3-NO2C6H4
2-ClC6H4
3-BrC6H4
4-CH3C6H4
4-OCH3C6H4
3
3
H2O
3
2.25
1.5
2.5
4
92
4
H2O
Reflux, 2.5 h 85
Reflux, 2.5 h 85
4
87
5
H2O
5
91
6
H2O
Reflux, 5 h
Reflux, 5 h
27 °C, 12 h
60 °C, 6 h
80 °C, 4.5 h
Reflux, 4 h
Reflux, 4 h
100 °C, 6 h
83
85
–
6
90
7
H2O
7
3, 4-(OCH3)2C6H3 4.5
3, 4-(CH2O2)C6H3 3.5
84
8
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
H2O
8
90
9
H2O
80
82
76
62
52
30
32
9
C6H5
3
84
10
11
12
13
14
15
H2O
10
11
12
13
14
15
C6H5
3-BrC6H4
4-OCH3C6H4
C6H5
2.5
5
78
Ethanol
DMF
DMSO
C6H5
84
4-BrC6H4
4-C2H5C6H4
C2H5
4
78
C6H5
5
88
Acetonitrile Reflux, 6 h
C6H5
1.5
1.5
87
DCM Reflux, 8 h
CH3
C6H5
86
Isatoic anhydride (1 mmol), NH4OAc (1.2 mmol) and Benzaldehyde
(1 mmol), solvent (2 mL)
Isatoic anhydride (5 mmol), NH4OAc (1.2 mmol) or amine (5 mmol),
Benzaldehyde (5 mmol), b-CD (1 mmol) and H2O (10 mL)
a
Isolated yield
a
Isolated yield based on isatoic anhydride; b Yield after third recycle
of aldehyde bearing either electron donating or electron
withdrawing groups on aromatic ring was investigated. The
reaction time was found to be short for aliphatic amines
with good to moderate yield of product (Table 2, entry 14,
15). The plausible general mechanistic pathway is shown in
Scheme 3. First the isatoic anhydride is activated with
microenvironment of b-CD cavity by the formation of
hydrogen bonding with carbonyl group followed by
nucleophilic attack of amine on the carbonyl group to give
intermediate-I. Then decarboxylation resulting into the
formation of intermediate-II followed by subsequent cyc-
lisation with aldehyde. b-CD was recovered in good
quantity with 95, 92 and 88 % for first, second and third
recycle respectively.
out under various conditions; the results are mentioned in
Table 1. The better result was obtained when 0.2 mmol of b-
CD used with short reaction time of 2 h and yield of 86 %
(Table 1, entry 3). The other organic solvents like ethanol,
DMF, DMSO, acetonitrile and DCM does not show signifi-
cant results. Increase in amount of catalyst also not show
improvement in results. The reaction also performed using
other ammonium salts like ammonium carbonate gives 73 %
of yield in 3 h where as with ammonium chloride affords
only 46 % and with long reaction time of 8 h.
To explore generality and scope of b-CD as a supra-
molecular catalyst, additional reaction of isatoic anhydride,
ammonium acetate or amines and benzaldehyde were
attempted. The result obtain are listed in Table 2. The array
123

J Incl Phenom Macrocycl Chem
Scheme 3 Plausible
mechanistic pathway for
synthesis of 2,3-
dihydroquinazolin-4(1H)-one
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Conclusion
In conclusion, the complex of isatoic anhydride and b-CD
was prepared by co-precipitation method. The inclusion
phenomena of isatoic anhydride with b-CD were success-
fully characterized by FTIR, XRD and DSC methods.
Based on this, we have developed a simple and ecofriendly
protocol for one-pot synthesis of 2,3-dihydroquinazolin-
4(1H)-ones in aqueous media using b-CD as a catalyst. The
advantage of procedure includes simplicity of operation,
good yields, low cost and recyclability of catalyst.
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to Dr. K. J. Patil, Emeritus Professor, School of Chemical Sciences
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