Microwave-promoted one-pot three-component synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by heteropolyanion-based ionic liquids under solvent-free conditions

Article abstract of DOI:10.1016/j.tet.2020.131312

A series of 2,3-dihydroquinazoline-4(1H)-one derivatives have been synthesized via one-pot three-component reaction using isatoic anhydrides, amines and aldehydes (or ketones) catalyzed by heteropolyanion-based ionic liquids under microwave-promoted conditions. The practical protocol was found to tolerate a wide range of substrates with different functional groups. Moderate to excellent yields, solvent-free media and operational simplicity are the main highlights. Furthermore, the catalyst can be recovered and reused without evident loss of reactivity. This method provides a green and much improved protocol over the existing methods.

Full text of DOI:10.1016/j.tet.2020.131312

Journal Pre-proof
Microwave-promoted one-pot three-component synthesis of 2,3-
dihydroquinazolin-4(1H)-ones catalyzed by heteropolyanion-based ionic liquids under
solvent-free conditions
Yang Yang, Renzhong Fu, Yang Liu, Jing Cai, Xiaojun Zeng
PII:
S0040-4020(20)30466-X
https://doi.org/10.1016/j.tet.2020.131312
TET 131312
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 9 March 2020
Revised Date: 10 May 2020
Accepted Date: 25 May 2020
Please cite this article as: Yang Y, Fu R, Liu Y, Cai J, Zeng X, Microwave-promoted one-pot three-
component synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by heteropolyanion-based ionic
liquids under solvent-free conditions, Tetrahedron (2020), doi: https://doi.org/10.1016/j.tet.2020.131312.
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Microwave-promoted one-pot three-
component synthesis of 2,3-
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dihydroquinazolin-4(1H)-ones catalyzed by
heteropolyanion-based ionic liquids under
solvent-free conditions
Yang Yang, Renzhong Fu*, Yang Liu, Jing Cai, Xiaojun Zeng
Jiangsu Laboratory of Advanced Functional Material, School of Materials Engineering, Changshu Institute of
Technology, Changshu 215500, China

1
Tetrahedron
journal homepage: www.elsevier.com
Microwave-promoted one-pot three-component synthesis of 2,3-dihydroquinazolin-
4(1H)-ones catalyzed by heteropolyanion-based ionic liquids under solvent-free
conditions
Yang Yang, Renzhong Fu , Yang Liu, Jing Cai, Xiaojun Zeng
Jiangsu Laboratory of Advanced Functional Material, School of Materials Engineering, Changshu Institute of Technology, Changshu 215500, China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A series of 2,3-dihydroquinazoline-4(1H)-one derivatives have been synthesized via one-pot
three-component reaction using isatoic anhydrides, amines and aldehydes (or ketones) catalyzed
by heteropolyanion-based ionic liquids under solvent-free and microwave-promoted conditions.
The practical protocol was found to tolerate a wide range of substrates with different functional
groups. Moderate to excellent yields, solvent-free media and operational simplicity are the main
highlights. Furthermore, the catalyst can be recovered and reused without evident loss of
reactivity. This method provides a green and much improved protocol over the existing methods.
Available online
Keywords:
Dihydroquinazolinone
Ionic liquid
2009 Elsevier Ltd. All rights reserved
.
Microwave
One-pot
Solvent-free
1. Introduction
-one derivatives can easily be oxidized to their quinazolin-4(3H)-
one analogues, which are also important biologically active
heterocycles.9 Regarding such prominent significance and
pharmaceutical utility, various procedures have been focused on
the construction of 2,3-dihydroquinazolin-4(1H)-one scaffolds as
stated in literature.10–18 Among them, a more attractive and atom-
efficient strategy for preparation of these compounds is one-pot
three-component condensation of isatoic anhydride, amines and
aldehydes, which was firstly reported by Salehi and coworkers in
2005.19–20 Until now, numerous protocols have been developed
recently for the synthesis using catalysts including acidic
reagents,21–29 lewis acids,30–36 nanoparticles37–46 and metal
complexes.47–49 These reported methodologies produce good
results in many cases, whereas most of those procedures are
associated with different negative aspects, such as long reaction
times, low yields, harsh acidic conditions, tedious work-up, use
of expensive reagents and toxic catalysts. The use of ionic liquids
was also reported for this conversion.50–54 However, the
requirement of reaction media and narrow substrates scope limit
the practical application in chemical industry. Therefore, the
development of a simple, practical, efficient and environmentally
N-heterocyclic molecules have attracted considerable attention
in current synthetic chemistry owing to their immense relevance
in wide-ranging areas of medicinal chemistry, pharmaceuticals,
agrochemicals, dyes and functional materials.1–4 2,3-
dihydroquinazolin-4(1H)-ones are considered as the privileged
heterocyclic skeletons for drug design due to their a broad range
of biological and pharmacological activities, such as anti-
inflammatory, antiviral, analgesic, antimicrobial and anticancer
activity (Fig. 1).5–8 Additionally, 2,3-dihydroquinazolin-4(1H)
benign
approach
for
the
preparation
of
2,3-
dihydroquinazolinones is still favored.
Fig. 1. Structures of pharmacologically active 2,3-dihydroquinazolin-4(1H)-
With the growing awareness of green and sustainable chemical
process, the use of alternative methods to perform organic
ones
.
———
Corresponding author. Tel.: +86-512-52251842; fax: +86-512-52251842; e-mail: renzhongfujs@126.com

2
Tetrahedron
readily available based on our previous publications in HPAIL
catalyzed organic reactions.67–74
At the onset of the research, the reaction of isatoic anhydride,
aniline and benzaldehyde was selected as a model reaction and
the effect of the different experimental variables related to the
isolated yields was investigated to optimize the reaction
conditions (Table 1). Firstly, control experiments were performed
Scheme 1. One-pot three-component synthesis of 2,3-
Dihydroquinazolin-4(1H)-ones.
o
synthesis under environmentally benign conditions is in focus.55
With this perspective, ionic liquids (ILs) have attracted more and
more interest as efficient and eco-friendly reaction catalysts
and/or media owing to their ease of recovery and reuse.56-58 In
particular, a family of heteropolyanion-based ILs (HPAILs) have
been obtained as new species of hybrid materials by combining
Keggin heteropolyanions with ‘taskspecific’ ILs (TSILs) cations
containing special functional groups.59 The distinctive properties
of HPAILs are high melting points, negligible vapour pressure,
thermal stability and chemical stability due to the large volume
and high valence of heteropolyanions and hydrogen bonding net-
works.60 So far, HPAILs have made significant contributions to
green chemistry and have been used widely as an attractive
alternative for traditional reagents61–63 because of their
operational simplicity, no toxicity, easy isolation and reusability.
Therefore, HPAILs have been turned out to be a novel candidate
for green and sustainable catalysts.
at room temperature and 60 C with conventional heating in the
absence of any catalyst and additional solvent and, as expected,
poor yields were observed even after a prolonged reaction time of
12 h (Table 1, entries 1-2). Whereas addition of 2 mol % amount
of [MIMPS]3PW12O40 to the reaction mixture at 60 oC with
conventional
heating
resulted
in
2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one with moderate yield (Table 1, entry
3). The results revealed that HPAILs could definitely promote
this reaction. In order to improve the yield, some adjustments to
the reaction conditions were made. To our delight, when MW
heating was utilized at 60 oC, 80 oC and 100 oC, it was shown that
the rate and yield of the reaction both increased dramatically with
80 oC as the prefered reaction temperature (Table 1, entries 3-5).
In addition, the amount of catalyst is important in the reaction
performance. Interestingly, the reaction was found to be equally
efficient with 3 mol % amount of [MIMPS]3PW12O40 (Table 1,
entry 6), while bringing down the catalyst loading to 1 mol % led
During the last few years, the potential of microwave (MW)
energy have been well explored in organic synthesis as a non-
classical approach to enhanced yields in significantly short
reaction times.64–65 Actually, MW irradiation enables the use of a
wide variety of experimental conditions. However, the focus is
now shifted to green and efficient procedure, that is MW
irradiation in conjunction with solvent-free conditions, which aim
for a straightforward process by simplifying the product recovery,
preventing waste generation as well as reducing the operational
costs.66 Following our ongoing efforts to develop novel, efficient
and green methods for organic transformations,67–74 herein we
report the synthesis of 2,3-dihydroquinazolin-4(1H)-ones through
MW-promoted one-pot three-component condensation of isatoic
anhydrides, amines and aldehydes (or ketones) using HPAILs as
the catalysts under solvent-free conditions (Scheme 1).
Table 1. Optimization of the reaction conditions for three-
component condensation of isatoic anhydride, aniline and
benzaldehyde.a
Entry
Temp Time
Yield
(%)b
trace
Catalyst [mol %]
-
(oC)
rt
(min)
720
1
2
3
4
5
6
7
8
60
60
80
100
80
80
80
720c
10c
-
[MIMPS]3PW12O40 [2]
240c, 25
120c, 15
120c, 15
15
56c, 63
75c, 86
73c, 83
86
[MIMPS]3PW12O40 [2]
[MIMPS]3PW12O40 [2]
[MIMPS]3PW12O40 [3]
[MIMPS]3PW12O40 [1]
[MIMPS]3PW12O40 [2]
2. Results and discussions
We initiated the investigation by employing the typical N-
substituted imidazole, pyridine and triethylamine fused HPAILs
(Fig. 2) as potential catalysts for this condensation, which were
15
65
15
48d, 35e,
28f, 15g,
58h
9
[MIMPS]3PMo12O40 [2] 80
20
15
20
25
30
80
90
82
75
68
10
11
12
13
[PyPS]3PW12O40 [2]
[PyPS]3PMo12O40 [2]
[TEAPS]3PW12O4 [2]
[TEAPS]3PMo12O40 [2]
80
80
80
80
a
Unless otherwise specified, all reactions were carried out with isatoic
anhydride 1a (2.0 mmol), aniline 2a (2.4 mmol), benzaldehyde 3a (2.4
mmol) and related catalyst under MW (700 W) and solvent-free conditions in
a sealed glass pressure tube.
b Isolated yields based on isatoic anhydride.
c Conventional heating.
d C2H5OH (1.0 mL) was used as solvent.
e CH3CN (1.0 mL) was used as solvent.
f 1,4-Dioxane (1.0 mL) was used as solvent.
g Toluene (1.0 mL) was used as solvent.
h H2O (1.0 mL) was used as solvent.
Fig. 2. N-substituted imidazole, pyrdine and triethylamine based HPAILs.

3
Table 2. HPAIL catalyzed three-component condensation of
to a reduction in the yield to 65 % (Table 1, entry 7). Next, to
compare the solvent-free condition versus solvent condition,
various solvents with different polarities such as C2H5OH,
CH3CN, 1,4-dioxane, Toluene and H2O were test in this reactions.
As depicted in Table 1 entry 8, an obvious decrease was found in
the yield with any solvent in the condensation. Then the catalytic
activities of other related HPAILs catalysts prepared earlier were
screened (Table 1 entries 9-13), more efficient results were
observed by switching the catalyst from MIMPS and TEAPS
species to PyPS species. Furthermore, in the case of catalysts
combining with different heteropolyanions the results
demonstrated that PW12O40 was more active than PMo12O40
HPAILs. Finally, the optimized condition was shown using 2
mol% of [PyPS]3PW12O40 under MW and solvent-free conditions
at 80 oC affording 2,3-diphenyl-2,3-dihydroquinazolin-4(1H)-one
in 90% yield (Table 1, entry 10).
isatoic anhydrides, amines and aldehydes (or ketones).a
Product: time (min)/yield (%)b
4b: 15/92
4e: 15/85
4a: 15/90
4d: 15/93
4c: 15/89
4f 20/78
In order to explore the scope and limitation of this three-
component process, the reactions of diverse isatoic anhydrides,
amines and aldehydes (or ketones) were conducted under the
optimized conditions. In general, a wide range of desired
dihydroquinazolinones 4a−33c were obtained in moderate to
excellent yields in all the cases within 10 to 25 min. Initially, as
illustrated in Table 2, when isatoic anhydride and benzaldehyde
were employed, reactions of aromatic amines bearing electron-
donating groups on the aryl nucleus afforded relatively higher
reactivity than those bearing electron-withdrawing counterparts
(Table 2, 4a–4g). And the heteroaromatic amines, including
pyridin-2-amine, thiazol-2-amine and benzo[d]thiazol-2-amine,
were found equally competent for the reaction and the desired
products were furnished in good yields (Table 2, 4h–4j).
Moreover, aliphatic amines and ammonium acetate (ammonia
source) were found to be effective substrates and afforded the
respective 2,3-dihydroquinazolin-4(1H)-one derivatives in
excellent yields and short reaction times (Table 2, 4k–4n). The
results can be explained that the stronger nucleophilicities of
amines could be beneficial for the transformation.
Subsequently, this protocol was surveyed with a variety of
aldehydes (or ketones) to further demonstrate its generality. The
results shown that the reaction was compatible with a variety of
substituents (Me, OMe, F, Cl, Br, NO2, CO2Me, CN and CF3) on
the aryl aldehyde moiety, which are very important functional
units for post-diversification in pharmaceutical chemistry. It
should be noted that the electronic effect and position of the
substituents on the phenyl rings seemed to have a certain but not
strong influence on this reaction, and reactions of aromatic
aldehydes possessing electron-rich substituents afforded little
better yields than those possessing the electron-poor substituents
(Table 2, entries 5a–18a). Satisfactorily, the reactions of aryl
4g: 20/80
4j: 30/76
4m: 10/85
6a: 15/88
4i: 20/78
4l: 10/88
5a: 15/90
4h: 20/82
4k:10/87
4nc: 10/92
7a: 15/86
10a: 20/85
12a: 20/83
8a: 15/85
11a: 20/85
13a: 20/81
16a: 20/80
9a: 20/88
11b: 20/82
aldehydes
containing
heteroatom,
such
as
15a: 20/81
18a: 20/78
14a: 25/75
17a: 20/85
20a: 20/87
pyridinecarboxaldehyde and thiophenecarboxaldehyde, were well
tolerated and furnished the corresponding products in good yields
(Table 2, entries 19a–21a). While 3-phenylpropanal as an
example of aliphatic aldehydes was checked under our standard
conditions, 2-amino-N-phenylbenzamide was the only product
(Table 2, 22a). However, with regard to the reactivities of
ketones, lower isolated yields and longer reaction times were
achieved as compared to the aldehydes substrates (Table 2,
entries 22a–23a).
19a: 20/84
22ad: 25/-
In order to enrich the diversity of the product library, further
extension of this transformation to different substituted isatoic
21a: 20/77

4
Tetrahedron
23a: 25/69
25a: 15/90
27a: 15/86
24a: 25/63
26b: 10/82
26a: 15/91
28a: 15/83
29a: 10/89
32a: 15/88
30a: 15/85
33a: 25/68
31a: 15/80
33b: 25/71
Scheme 2. Control experiments for the mechanism study.
33c: 25/75
reaction mixture via simple centrifugation or filtration, washed
with ethyl acetate to remove traces of the previous reaction
mixture and then dried. The recovered catalyst was reused
directly for further four runs in the same reaction. As is evident
from Fig. 3, the catalyst can be reused without appreciable loss of
catalytic efficiency. Furthermore, the recycled [PyPS]3PW12O40
catalyst was characterized and the results indicated the
maintaining of the original structure (detailed spectra in
Supplementary Material). The slight decrease in the observed
yield is probably attributed to inadequate recovery of the catalyst
due to the attrition during filtration. Thus, that proved the
robustness of HPAILs and their reusability in this reaction.
a
Unless otherwise specified, all reactions were carried out with isatoic
anhydrides 1 (2.0 mmol), amines 2 (2.4 mmol), aldehydes 3 (or ketones) (2.4
mmol) and [PyPS]3PW12O40 (2 mol %) under MW (700 W) and solvent-free
conditions at 80 oC in a sealed glass pressure tube.
b Isolated yields based on isatoic anhydrides.
c Ammonium acetate was used as ammonia source.
d 2-Amino-N-phenylbenzamide was the only product.
anhydrides was performed. It is pleased to find that various
functional groups (Me, OMe, F, Cl and Br) in different positions
of isatoic anhydride could be well tolerated with this protocol,
affording the desired products in good yields (Table 2, entries
25a–32a). Additionally, when N-Methylisatoic anhydride was
introduced as substrate, the desired 2,3-dihydroquinazolin-4(1H)-
one derivatives were obtained in moderate yields (Table 2,
entries 33a–33c). Finally, the above results proved the generality
of this method access to multisubstituted 2,3-dihydroquinazolin-
4(1H)-one derivatives.
In the view of sustainable chemistry, another distinguishing
feature of HPAILs catalyzed process is recovery and reusability,
the potential recycling of HPAILs was investigated using the
model reaction of isatoic anhydride, aniline and benzaldehyde.
Upon accomplishment of the reaction in the frist run, hot EtOAc
was added to dissolve the organic products. After vigorous
stirring, [PyPS]3PW12O40 can be easily separated from the
According to the mechanism suggested by previous reports,19-
49
one of the possible intermediates for the reaction might be 2-
aminobenzamide derivatives. In order to elucidate the reaction
mechanism of this one-pot three-component condensation, some
control experiments were performed. Firstly, 2-amino-N-
phenylbenzamide was successfully prepared from the reaction of
isatoic anhydride with aniline under the standard condition
(Scheme 2, eqn (1)), which is consistent with reports in the
literature.75 Secondly, when 2-amino-N-phenylbenzamide reacted
with benzaldehyde, the corresponding 2,3-dihydroquinazolin-
4(1H)-one product was formed in the presence of
[PyPS]3PW12O40 (Scheme 2, eqn (2) ). In addition, the reactions
of isatoic anhydride with benzaldehyde and aniline with
benzaldehyde did not proceed to 2,3-dihydroquinazolin-4(1H)-
one under the same conditions (Scheme 2, eqn (3) and eqn (4)).
Thus, the results revealed that the 2-amino-N-phenylbenzamide
should be absolutely the key intermediate. In addition, to further
understand the catalytic effect of [PyPS]3PW12O40, the PyPS
cation and the PW12O40 anion were used respectively as the
catalyst under the same conditons. As shown in Scheme 2 eqn (5)
and eqn (6), the yields were almost comparable with PyPSCl and
[PyPS]3PW12O40, while H3PW12O40 exhibited the relatively lower
catalytic activity. It was implied that no significant coordination
of cation and anion was observed, and the PyPS cation played an
important role in the catalytic reaction as well.
Fig. 3. Reusability studies of the catalyst for the one-pot three-component
condensation.

5
comparison with some other reported catalysts, several results
for the preparation of 2,3-dihydroquinazolin-4(1H)-ones from the
model reaction of isatoic anhydride 1a, aniline 2a and
benzaldehyde 3a were summarized. As shown in Table 3, the
[PyPS]3PW12O40 (Table 3, entry 12) gives better yields or shorter
reaction times than other catalysts.
3. Conclusion
In conclusion, the MW-promoted syhthesis of 2,3-
dihydroquinazolin-4(1H)-one family via one-pot three-
component condensation of isatoic anhydrides, amines and
aldehydes (or ketones) using HPAILs as catalyst is introduced.
Compared to previous reported methodologies, the present
procedure offers several advantages, such as simple operations,
short reaction times, environmental compatibility, reusability of
catalyst and the compatibility with various functional groups. It is
expected that this method could find extensive applications in the
synthesis of many biologically active derivatives.
Fig. 4. Plausible mechanism of HPAIL catalyzed one-pot three-component
condensation.
On the basis of the points mentioned above, a reasonable
mechanism for the preparation of 2,3-dihydroquinazolin-4(1H)-
one derivatives using HPAILs is proposed in Fig 4. Initially, the
activation of carbonyl of isatoic anhydride (I) and N–H bond in
amine are achieved via coordination with the aminium cation and
sulfonic group in the HPAIL cation respectively to produce a
reactive intermediate (II). Subsequently, N-nucleophilic primary
amine attack on the carbonyl unit and ring opening form a
dipolar adduct (III), which in turn generates intermediate (IV)
via decarboxylation. Upon the proton transfer reaction, the key
intermediate 2-amino-N-substituted benzamide (V) is afforded.
Afterwards, the HPAIL cation activate carbonyl of aldehyde (or
ketone) and N–H bond in 2-aminobenzamide (V) respectively,
followed by addition of the amine to the carbonyl carbon to result
in the formation of the dipolar adduct (VI). Finally, the proton
transfer leads to intermediate VII, which in turn affords the target
product VIII by a ring closure via dehydration.
4. Experimental section
4.1. General methods
Reagent grade solvents were used for extraction,
recrystallization and flash chromatography. All other commercial
reagents were used as received without additional purification.
The progress of reactions were checked by analytical thin-layer
chromatography (TLC, silica gel 60 F-254 plates) (Qingdao
Haiyang Chemical Co., Ltd, Qingdao, Shandong, China). The
plates were visualized first with UV illumination followed by
iodine
or
phosphomolybdic
acid
hydrate.
Column
chromatography was performed using silica gel (200-300 mesh)
(Qingdao Haiyang Chemical Co., Ltd, Qingdao, Shandong,
China). NMR spectra were obtained using BRUKER AVANCE
1
III instrument. H NMR spectra were recorded at 300 MHz or
Finally, in order to show the advantages of the present work in
400 MHz and are reported in parts per million (ppm) on the δ
scale relative to tetramethylsilane (TMS) as an internal standard.
13C NMR spectra were recorded at 75 MHz or 100 MHz and are
reported in parts per million (ppm) on the δ scale relative to
CDCl3 (δ 77.16) and DMSO-d6 (δ 39.52). Multiplicities are
indicated as the following : s, singlet; d, doublet; t, triplet; q,
quartet; m, multiplet; dd, doubled doublet; td, tripled doublet; br,
broad. Coupling constants (J values) where noted are quoted in
hertz. Mass spectra were obtained using Agilent 1260-6120 (ESI)
instrument (Agilent Technologies Co., Ltd, Santa Clara, Calif.
USA). MW-promoted heating was obtained using MAS-II
instrument manufactured by Shanghai Sineo Microwave
Chemistry Technology Co., Ltd. The melting point was
uncorrected.
Table 3. Comparison of [PyPS]3PW12O40 with other reported
catalysts in the reaction of isatoic anhydride, aniline and
benzaldehyde.
Entry Catalyst
Conditions
Time
Ref.
(min)/Yield (%)
1
PTSA-
Ethanol, 80 °C 390/82
22
paraformaldehyde
copolymer
2
3
4
H2O, 100 °C
H2O, 80 °C
300/94
90/77
28/90
23
24
29
EDDA
Citric acid
Solvent-free,
100 °C
Starch sulfate
SiO2-FeCl3
5
6
Solvent-free,
80 °C
27/89
30/91
32
33
4.2. General Procedure for the Synthesis of HPAILs
H3PO4–Al2O3
Solvent-free,
100 °C
To a mixture of toluene (30 mL) and 1,3-propane sulfone
(0.10 mol, 12.2 g) in a 100 mL round bottomed flask was added
pyridine (0.11 mol, 8.7 g, 8.9 mL). The reaction mixture was
stirred for 24 h at 50 oC under a nitrogen atmosphere until a white
precipitate (PyPS) was formed. After the completion of reaction,
it was cooled to room temperature. After filtration, washing with
diethyl ether and drying in a vacuum, PyPS was obtained. Then,
PyPS (0.09 mol, 18.1 g) was added to an aqueous solution of
H3PW12O40 (0.03 mol, 86.4 g) and then the mixture was stirred at
room temperature for 24 h. Finally, the solution was removed in
vacuum to give the HPAIL product [PyPS]3PW12O40 as a solid.
7
8
Fe3O4 nanoparticle H2O, 100 °C
120/80
180/85
37
41
CuO nanoparticle
Aqueous
ethanol, reflux
9
Nano-In2O3
Aqueous
ethanol, 80 °C
240/87
90/90
90/91
15/90
42
48
49
10
11
12
Aluminum
methanesulfonate
Aqueous
ethanol, reflux
Copper
benzenesulfonate
Aqueous
ethanol, reflux
Thus
[PyPS]3PMo12O40,
[MIMPS]3PW12O40,
[PyPS]3PW12O40
Solvent-free,
MW, 80 °C
This
work
[MIMPS]3PMo12O40, [TEAPS]3PW12O40 and [TEAPS]3PMo12O40
were prepared using according starting materials.

6
Tetrahedron
4.2.1. 1-Methyl-3-(3-sulfopropyl)imidazole (MIMPS)
White solid. Mp: 185.5-187.8 °C; IR (KBr) : 3440, 1485,
1460, 1400, 1230, 1170, 1080, 978, 893, 810 cm-1; 1H NMR (400
MHz, D2O) δ 3.29-3.28 (m, 8H), 2.98-2.93 (m, 2H), 2.17-2.01 (m,
2H), 1.28-1.25 (m, 9H); 13C NMR (100 MHz, D2O) δ 60.2, 52.9,
48.0, 24.3, 6.7; HRMS Calcd for C9H22NO3S (M + H+): 224.1315;
Found: 224.1318.
White solid. Mp: 55.5-58.8 °C; IR (KBr) : 3433, 3025, 2944,
1631, 1487, 1328, 1197, 1099, 775, 687, 604, 522, 481 cm-1; H
1
NMR (400 MHz, D2O) δ 8.71 (s, 1H), 7.48 (s, 1H), 7.41 (s, 1H),
4.32 (t, J = 7.2 Hz, 2H), 3.86 (s, 3H), 2.88 (t, J = 7.2 Hz, 2H),
2.31-2.24 (m, 2H); 13C NMR (100 MHz, D2O) δ 136.2, 123.8,
122.2, 47.8, 47.3, 35.8, 25.1; HRMS Calcd for C7H13N2O3S (M +
H+): 205.0641; Found: 205.0645.
4.2.9. Triethyl-(3-sulfopropyl)aminium
hosphomolybdate ([TEAPS]3 PMo1 2 O4 0
)
1
4.2.2. 1-(3-Sulfopropyl)pyridine (PyPS).
Green solid. Mp: 165.5-167.8 °C; H NMR (400 MHz, D2O) δ
3.37-3.21 (m, 8H), 2.97-2.87 (m, 2H), 2.16-2.06 (m, 2H), 1.28-
1.25 (m, 9H); 13C NMR (100 MHz, D2O) δ 60.2, 52.9, 48.0, 24.3,
6.7; HRMS Calcd for C9H22NO3S (M + H+): 224.1315; Found:
224.1318.
White solid. Mp: 62.5-64.8 °C; IR (KBr) : 3443, 3159, 3103,
1572, 1459, 1184, 1010, 842, 780, 654, 601, 528 cm-1; H NMR
1
(400 MHz, D2O) δ 8.86 (d, J = 6.0 Hz, 2H), 8.53 (t, J = 7.8 Hz,
1H), 8.06 (t, J = 7.6 Hz, 2H), 4.75 (t, J = 7.2 Hz, 2H), 2.95 (t, J =
7.2 Hz, 2H), 2.47-2.40 (m, 2H); 13C NMR (100 MHz, D2O) δ
146.0, 144.5, 128.5, 60.0, 47.1, 26.2; HRMS Calcd for
C8H12NO3S (M + H+): 202.0532; Found: 202.0534.
4.3. General procedure for the synthesis 2,3-dihydroquinazolin-
4(1H)-ones
To a mixture of isatoic anhydride (2 mmol), amine (2.4 mmol)
and aldehyde (or ketone) (2.4 mmol) in a 15 mL glass pressure
tube was added [PyPS]3PW12O40 (0.14 g, 0.04 mmol). After the
pressure tube was closed, the reaction mixture was stirred at 80
oC under MW (700 W). The progress of the reaction could be
monitored by TLC. After the reaction is completed, the mixture
was diluted with hot ethyl acetate (30 mL) with stirring for 30
min. After filtration, the filtrate was evaporated and the residue
was directly purified by recrystallization or column
chromatography to give the desired product. And the insoluble
[PyPS]3PW12O40 catalyst was recovered. After washing with
ethyl acetate (10 mL) to remove traces of the previous reaction
mixture and then drying under vacuum, the recovered
[PyPS]3PW12O40 catalyst could be used for further runs for the
same reaction.
4.2.3. Triethyl-(3-sulfopropyl)amine (TEAPS)
1
White solid. Mp: 48.5-49.8 °C; H NMR (400 MHz, D2O) δ
3.27 (q, J = 7.2 Hz, 8H), 2.93 (t, J = 7.2 Hz, 2H), 2.10-2.06 (m,
2H), 1.27-1.20 (m, 9H); 13C NMR (100 MHz, D2O) δ 52.7, 47.3,
46.7, 17.3, 8.3; HRMS Calcd for C9H22NO3S (M + H+): 224.1315;
Found: 224.1318.
4.2.4. 1-Methyl-3-(3-sulfopropyl)imidazolium
phosphotungstate ([MIMPS]3 PW1 2 O4 0
)
White solid. Mp: 119.5-120.8 °C; IR (KBr) : 3417, 3147,
1636, 1571, 1459, 1418, 1173, 1080, 980, 897, 800, 516 cm-1; 1H
NMR (400 MHz, D2O) δ 8.68 (s, 1H), 7.55 (s, 1H), 7.51 (s, 1H),
4.42 (t, J = 7.2 Hz, 2H), 4.02 (s, 3H), 2.91 (t, J = 7.2 Hz, 2H),
2.36-2.28 (m, 2H); 13C NMR (100 MHz, D2O) δ 135.9, 124.2,
122.6, 48.1, 47.4, 36.1, 25.3; HRMS Calcd for C7H13N2O3S (M +
H+): 205.0641; Found: 205.0645.
4.3.1. 2,3-Diphenyl-2,3-dihydroquinazolin-4(1H)-
one (4a)
4.2.5. 1-Methyl-3-(3-sulfopropyl)imidazolium
1
White solid. Mp: 207.3-209.1 °C; H NMR (400 MHz, CDCl3)
hosphomolybdate ([MIMPS]3 PMo1 2 O4 0
)
δ 7.93 (d, J = 6.8 Hz, 1H), 7.29-7.24 (m, 2H), 7.21-7.14 (m, 6H),
7.11-7.09 (m, 3H), 6.79 (t, J = 6.8 Hz, 1H), 6.53 (d, J = 7.6 Hz,
1H), 6.00 (s, 1H), 4.82 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ
163.3, 145.5, 140.7, 140.0, 134.0, 129.2, 129.1, 129.0, 128.8,
127.1, 126.9, 126.8, 119.7, 117.0, 115.0, 74.8; HRMS Calcd for
C20H17N2O (M + H+): 301.1335; Found: 301.1339.
Green solid. Mp: 105.5-108.8 °C; IR (KBr) : 3422, 3149,
3100, 1630, 1569, 1454, 1405, 1217, 1171, 1059, 963, 882, 796,
610, 504 cm-1; 1H NMR (400 MHz, D2O) δ 8.63 (s, 1H), 7.48 (s,
1H), 7.42 (s, 1H), 4.35 (brs, 2H), 3.92 (s, 3H), 2.86 (brs, 2H),
2.26 (brs, 2H); 13C NMR (100 MHz, D2O) δ 136.3, 124.3, 122.6,
48.2, 47.4, 36.1, 25.3; HRMS Calcd for C7H13N2O3S (M + H+):
205.0641; Found: 205.0643.
4.3.2. 2-Phenyl-3-(p-tolyl)-2,3-dihydroquinazolin-
4(1H)-one (4b)
4.2.6. 1-(3-Sulfopropyl)pyridinium
phosphotungstate ([PyPS]3 PW1 2 O4 0
1
White solid. Mp: 214.2-216.2 °C; H NMR (400 MHz, CDCl3)
)
δ 7.92 (d, J = 7.6 Hz, 1H), 7.26-7.25 (m, 2H), 7.21-7.18 (m, 4H),
6.97 (brs, 4H), 6.77 (t, J = 7.2 Hz, 1H), 6.51 (d, J = 8.0 Hz, 1H),
5.95 (s, 1H), 4.94 (brs, 1H), 2.18 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 163.3, 145.5, 140.0, 138.0, 136.7, 133.9, 129.6, 129.0,
128.9, 128.7, 126.9, 126.8, 119.4, 116.7, 114.8, 74.7, 21.1;
HRMS Calcd for C21H19N2O (M + H+): 315.1492; Found:
315.1493.
White solid. Mp: 142.5-145.8 °C; IR (KBr) : 3409, 3131,
3068, 1633, 1488, 1220, 1182, 1079, 1042, 978, 896, 805, 681,
1
595, 521 cm-1; H NMR (400 MHz, D2O) δ 8.87 (brs, 2H), 8.59
(brs, 1H), 8.11 (brs, 2H), 4.78 (brs, 2H), 2.97 (brs, 2H), 2.46 (brs,
2H); 13C NMR (100 MHz, D2O) δ 146.3, 144.4, 128.6, 60.2, 47.2,
26.2; HRMS Calcd for C8H12NO3S (M + H+): 202.0532; Found:
202.0535.
4.3.3. 2-Phenyl-3-(o-tolyl)-2,3-dihydroquinazolin-
4.2.7. 1-(3-Sulfopropyl)pyridinium
hosphomolybdate ([PyPS]3 PMo1 2 O4 0
4(1H)-one (4c)
)
1
White solid. Mp: 216.2-218.2 °C; H NMR (400 MHz, CDCl3)
Green solid. Mp: 142.5-145.8 °C; IR (KBr) : 3421, 3066,
1633, 1488, 1181, 1062, 1044, 957, 880, 795, 680, 609, 505 cm-1;
1H NMR (400 MHz, D2O) δ 8.87 (brs, 2H), 8.67 (t, J = 7.2 Hz,
1H), 8.20 (t, J = 7.2 Hz, 2H), 4.82 (t, J = 7.2 Hz, 2H), 2.98 (t, J =
7.2 Hz, 2H), 2.51-2.43 (m, 2H); 13C NMR (100 MHz, D2O) δ
146.4, 144.3, 129.0, 60.3, 47.3, 26.5; HRMS Calcd for
C8H12NO3S (M + H+): 202.0532; Found: 202.0536.
δ 8.00 (d, J = 7.2 Hz, 1H), 7.29-7.26 (m, 5H), 7.20-7.12 (m, 3H),
6.99 (t, J = 7.6 Hz, 1H), 6.88 (t, J = 7.6 Hz, 1H), 6.74 (d, J = 7.6
Hz, 1H), 5.59 (d, J = 7.6 Hz, 1H), 5.77 (s, 1H), 4.78 (s, 1H), 2.39
(s, 3H); 13C NMR (100 MHz, CDCl3) δ 162.5, 145.7, 140.3,
139.3, 135.7, 133.9, 131.2, 129.6, 129.3, 128.9, 128.5, 128.0,
126.7, 126.5, 119.5, 116.5, 114.7, 74.6, 18.3; HRMS Calcd for
C21H19N2O (M + H+): 315.1492; Found: 315.1495.
4.2.8. Triethyl-(3-sulfopropyl)aminium
phosphotungstate ([TEAPS]3 PW1 2 O4 0
4.3.4. 3-(4-Methoxyphenyl)-2-phenyl-2,3-
dihydroquinazolin-4(1H)-one (4d)
)

7
1
White solid. Mp: 117.3-119.3 °C; H NMR (400 MHz, CDCl3)
White soild. Mp: 158.3-161.4 °C; 1H NMR (400 MHz,
δ 8.00 (d, J = 7.6 Hz, 1H), 7.36-7.32 (m, 2H), 7.30-7.26 (m, 4H),
7.06 (d, J = 8.8 Hz, 2H), 6.86 (t, J = 7.6 Hz, 1H), 6.77 (d, J = 8.8
Hz, 2H), 6.59 (d, J = 8.0 Hz, 1H), 6.03 (s, 1H), 5.13 (brs, 1H),
3.72 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 163.5, 158.3, 145.6,
140.0, 133.9, 133.3, 129.1, 128.8, 128.6, 127.0, 125.1, 119.5,
116.6, 114.8, 114.3, 75.2, 55.5; HRMS Calcd for C21H19N2O2 (M
+ H+): 331.1441; Found: 331.1444.
CDCl3) δ 8.02 (d, J = 7.6 Hz, 1H), 7.85 (d, J = 8.0 Hz, 1H), 7.78
(d, J = 8.0 Hz, 1H), 7.72 (s, 1H), 7.47 (t, J = 7.6 Hz, 1H), 7.42 (t,
J = 7.6 Hz, 1H), 7.37-7.35 (m, 2H), 7.31 (t, J = 7.6 Hz, 1H),
7.22-7.20 (m, 3H), 6.90 (t, J = 7.6 Hz, 1H), 6.80 (t, J = 8.0 Hz,
1H), 5.33 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ 162.1, 158.3,
148.3, 145.4, 139.4, 135.3, 133.5, 130.2, 129.5, 128.8, 128.6,
126.2, 126.1, 124.1, 121.4, 121.3, 120.4, 116.3, 68.9; HRMS
Calcd for C21H16N3OS (M + H+): 358.1009; Found: 358.1007.
4.3.5. 3-(4-Chlorophenyl)-2-phenyl-2,3-
dihydroquinazolin-4(1H)-one (4e)
4.3.11. 3-Phenethyl-2-phenyl-2,3-
1
dihydroquinazolin-4(1H)-one (4k)
White solid. Mp: 133.3-135.3 °C; H NMR (400 MHz, CDCl3)
1
δ 8.07 (d, J = 7.2 Hz, 1H), 7.39-7.33 (m, 3H), 7.28-7.23 (m, 3H),
7.18-7.16 (m, 2H), 7.05 (d, J = 8.4 Hz, 2H), 6.95 (t, J = 7.6 Hz,
1H), 6.83 (d, J = 8.0 Hz, 1H), 5.77 (s, 1H), 5.08 (brs, 1H); 13C
NMR (100 MHz, CDCl3) δ 162.5, 146.5, 138.3, 136.7, 134.3,
129.3, 129.1, 128.8, 128.2, 128.0, 127.5, 126.7, 120.3, 119.5,
115.9, 78.1; HRMS Calcd for C20H16ClN2O (M + H+): 335.0946;
Found: 335.0948.
White solid. Mp: 178.3-179.1 °C; H NMR (400 MHz, CDCl3)
δ 7.91 (d, J = 7.6 Hz, 1H), 7.28 (s, 5H), 7.20-7.17 (m, 4H), 7.04
(d, J = 7.2 Hz, 2H), 6.79 (t, J = 7.6 Hz, 1H), 6.46 (d, J = 8.0 Hz,
1H), 5.48 (s, 1H), 4.39 (brs, 1H), 4.02-3.94 (m, 1H), 2.98-2.85
(m, 2H), 2.75-2.68 (m, 1H); 13C NMR (100 MHz, CDCl3) δ
163.4, 145.3, 139.6, 139.3, 133.6, 129.6, 129.1, 129.0, 128.6,
128.5, 127.0, 126.5, 119.5, 116.3, 114.5, 73.1, 47.1, 34.3; HRMS
Calcd for C22H21N2O (M + H+): 329.1648; Found: 329.1649.
4.3.6. 3-(4-Nitrophenyl)-2-phenyl-2,3-
dihydroquinazolin-4(1H)-one (4f)
4.3.12. 3-Octyl-2-phenyl-2,3-dihydroquinazolin-
1
4(1H)-one (4l)
White solid. Mp: 133.3-135.3 °C; H NMR (400 MHz, CDCl3)
1
δ 8.12 (d, J = 7.2 Hz, 1H), 8.08 (d, J = 8.8 Hz, 2H), 7.62 (t, J =
7.6 Hz, 1H), 7.48 (t, J = 7.6 Hz, 1H), 7.40-7.30 (m, 6H), 6.57 (d,
J = 8.8 Hz, 2H), 6.15 (s, 1H), 4.92 (brs, 1H); 13C NMR (100
MHz, CDCl3) δ 171.7, 165.4, 152.2, 146.7, 138.4, 137.5, 133.9,
130.3, 129.3, 129.1, 128.6, 128.0, 127.5, 126.5, 111.5, 77.4;
HRMS Calcd for C20H16N3O3 (M + H+): 346.1186; Found:
346.1188.
White solid. Mp: 148.3-150.3 °C; H NMR (400 MHz, CDCl3)
δ 7.95 (d, J = 7.6 Hz, 1H), 7.38-7.33 (m, 5H), 7.22 (t, J = 7.6 Hz,
1H), 6.83 (t, J = 7.6 Hz, 1H), 6.51 (d, J = 8.0 Hz, 1H), 5.74 (s,
1H), 4.56 (s, 1H), 3.98-3.91 (m, 1H), 2.79-2.72 (m, 1H), 1.62-
1.49 (m, 2H), 1.22 (s, 10H), 0.86 (t, J = 7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3) δ 163.2, 145.1, 140.1, 133.4, 129.4, 129.1,
128.6, 126.7, 119.3, 116.5, 114.4, 72.3, 44.9, 31.9, 29.4, 29.3,
27.8, 27.1, 22.8, 14.2; HRMS Calcd for C22H29N2O (M + H+):
337.2274; Found: 337.2276.
4.3.7. 3-(Naphthalen-1-yl)-2-phenyl-2,3-
dihydroquinazolin-4(1H)-one (4g)
1
4.3.13. 3-Cyclohexyl-2-phenyl-2,3-
White solid. Mp: 147.3-149.3 °C; H NMR (400 MHz, CDCl3)
dihydroquinazolin-4(1H)-one (4m)
δ 8.18 (d, J = 8.0 Hz, 1H), 8.06 (d, J = 7.2 Hz, 1H), 7.88 (d, J =
7.6 Hz, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.56-7.51 (m, 2H), 7.33-
7.26 (m, 5H), 7.25-7.23 (m, 2H), 7.05 (d, J = 7.6 Hz, 1H), 6.91 (t,
J = 7.6 Hz, 1H), 6.64 (d, J = 8.0 Hz, 1H) 5.94 (s, 1H), 4.86 (brs,
1H); 13C NMR (100 MHz, CDCl3) δ 163.1, 145.8, 140.4, 136.5,
134.9, 134.1, 129.3, 128.9, 128.8, 128.5, 128.3, 128.2, 127.9,
127.3, 126.6, 126.4, 125.5, 122.8, 119.6, 116.4, 114.7, 74.8;
HRMS Calcd for C24H19N2O (M + H+): 351.1492; Found:
351.1494.
1
White solid. Mp: 124.1-127.3 °C; H NMR (400 MHz, CDCl3)
δ 7.96 (d, J = 8.0 Hz, 1H), 7.31-7.29 (m, 2H), 7.26-7.24 (m, 3H),
7.16 (t, J = 7.6 Hz, 1H), 6.81 (t, J = 7.6 Hz, 1H), 6.45 (d, J = 8.0
Hz, 1H), 5.76 (s, 1H), 4.62 (brs, 1H), 4.58 (tt, J = 12.0, 3.2 Hz,
1H), 1.89-1.79 (m, 2H), 1.66-1.54 (m, 4H), 1.46-1.39 (m, 1H),
1.34-1.27 (m, 1H), 1.04-0.97 (m, 2H); 13C NMR (100 MHz,
CDCl3) δ 162.8, 144.2, 142.3, 133.3, 128.8, 128.6, 128.5, 125.8,
119.5, 117.8, 114.9, 67.7, 53.7, 31.2, 31.1, 26.0, 25.9, 25.6;
HRMS Calcd for C20H23N2O (M + H+): 307.1805; Found:
307.1807.
4.3.8. 2-Phenyl-3-(pyridin-2-yl)-2,3-
dihydroquinazolin-4(1H)-one (4h)
1
4.3.14. 2-Phenyl-2,3-dihydroquinazolin-4(1H)-one
(4n)
White solid. Mp: 181.1-183.3 °C; H NMR (400 MHz, CDCl3)
δ 8.33 (s, 1H), 8.20 (d, J = 8.0 Hz, 1H), 7.99 (d, J = 7.2 Hz, 1H),
7.70 (t, J = 7.2 Hz, 1H), 7.36-7.34 (m, 2H), 7.26 (brs, 3H), 7.22-
7.20 (m, 2H), 7.04 (s, 1H), 6.85 (t, J = 7.2 Hz, 1H), 6.74 (d, J =
8.0 Hz, 1H), 5.22 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 163.7,
152.6, 147.8, 145.5, 140.6, 137.6, 134.3, 129.4, 128.5, 128.1,
126.6, 120.2, 119.8, 119.0, 118.2, 115.9, 68.2; HRMS Calcd for
C19H16N3O (M + H+): 302.1288; Found: 302.1290.
White solid. Mp: 197.3-199.1 °C; 1H NMR (400 MHz,
DMSO-d6) δ 8.26 (brs, 1H), 7.62 (d, J = 7.6 Hz, 1H), 7.50 (d, J =
7.2 Hz, 2H), 7.41-7.42 (m, 3H), 7.24 (t, J = 7.6 Hz, 1H), 7.09
(brs, 1H), 6.76 (d, J = 8.0 Hz, 1H), 6.68 (t, J = 7.6 Hz, 1H), 5.76
(s, 1H); 13C NMR (100 MHz, DMSO-d6) δ 163.5, 147.8, 141.6,
133.2, 128.4, 128.3, 127.3, 126.8, 117.1, 114.9, 114.4, 66.5;
HRMS Calcd for C14H13N2O (M + H+): 225.1022; Found:
225.1020.
4.3.9. 2-Phenyl-3-(thiazol-2-yl)-2,3-
dihydroquinazolin-4(1H)-one (4i)
1
4.3.15. 3-Phenyl-2-(p-tolyl)-2,3-dihydroquinazolin-
4(1H)-one (5a)
White soild. Mp: 148.3-151.4 °C; H NMR (400 MHz, CDCl3)
δ 8.01 (d, J = 8.0 Hz, 1H), 7.51 (d, J = 10.8 Hz, 2H), 7.36-7.29
(m, 4H), 7.22 (d, J = 3.6 Hz, 2H) 7.04 (d, J = 3.2 Hz, 1H), 6.90 (t,
J = 7.6 Hz, 1H), 6.75 (d, J = 8.0 Hz, 1H), 5.25 (s, 1H); 13C NMR
(100 MHz, CDCl3) δ 161.4, 158.4, 145.1, 139.5, 137.3, 135.0,
130.2, 129.2, 128.8, 128.6, 126.1, 120.3, 116.1, 115.2, 69.0;
HRMS Calcd for C17H14N3OS (M + H+): 308.0852; Found:
308.0856.
White solid. Mp: 194.8-196.2 °C; 1H NMR (400 MHz,
DMSO-d6) δ 7.72 (d, J = 7.6 Hz, 1H), 7.59 (s, 1H), 7.34-7.31 (m,
2H), 7.27-7.25 (m, 5H), 7.20-7.16 (m, 1H), 7.10 (d, J = 8.0 Hz,
2H), 6.75 (d, J = 8.0 Hz, 1H), 6.71 (t, J = 7.6 Hz, 1H), 6.23 (d, J
= 2.4 Hz, 1H), 2.22 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ
162.8, 147.0, 141.4, 138.3, 138.0, 134.2, 129.4, 129.1, 128.4,
127.0, 126.6, 126.4, 117.9, 115.9, 115.3, 72.9, 21.1; HRMS
Calcd for C21H19N2O (M + H+): 315.1492; Found: 315.1494.
4.3.10. 3-(Benzo[d]thiazol-2-yl)-2-phenyl-2,3-
dihydroquinazolin-4(1H)-one (4j)

8
Tetrahedron
4.3.16. 2-(4-Methoxyphenyl)-3-phenyl-2,3-
7.21 (m, 3H), 6.84 (t, J = 7.6 Hz, 1H), 6.53 (d, J = 8.0 Hz, 1H),
dihydroquinazolin-4(1H)-one (6a)
6.29-6.28 (m, 1H), 6.20 (d, J = 2.4 Hz, 1H), 5.75 (s, 1H), 5.30 (d,
J = 15.6 Hz, 1H), 4.65 (s, 1H), 3.84 (d, J = 15.6 Hz, 1H); 13C
NMR (100 MHz, CDCl3) δ 163.1, 150.2, 145.1, 142.4, 138.5,
133.9, 132.2, 128.9, 128.5, 123.5, 119.6, 115.8, 114.6, 110.6,
109.1, 71.2, 40.2; HRMS Calcd for C19H16BrN2O2 (M + H+):
383.0390; Found: 383.0394.
1
White soild. Mp: 130.3-132.4 °C; H NMR (400 MHz, CDCl3)
δ 8.01 (d, J = 7.6 Hz, 1H), 7.53 (d, J = 8.4 Hz, 1H), 7.31-7.27 (m,
4H), 7.17-7.25 (m, 3H), 6.88 (t, J = 7.6 Hz, 1H), 6.76 (d, J = 8.0
Hz, 2H), 6.62 (d, J = 8.0 Hz, 1H), 6.05 (s, 1H), 5.13 (s, 1H), 3.74
(s, 3H); 13C NMR (100 MHz, CDCl3) δ 163.5, 160.0, 145.6,
140.6, 134.0, 130.9, 129.1, 129.0, 128.3, 127.3, 126.9, 119.6,
114.9, 114.0, 113.5, 74.4, 55.3; HRMS Calcd for C21H19N2O2 (M
+ H+): 331.1441; Found: 331.1444.
4.3.23. 2-(3-Bromophenyl)-3-phenyl-2,3-
dihydroquinazolin-4(1H)-one (12a)
1
White soild. Mp: 151.3-153.4 °C; H NMR (400 MHz, CDCl3)
4.3.17. 2-(3-Methoxyphenyl)-3-phenyl-2,3-
δ 8.02 (d, J = 7.6 Hz, 1H), 7.51 (s, 1H), 7.40 (d, J = 8.0 Hz, 1H),
7.32-7.30 (m, 4H), 7.23-7.19 (m, 3H), 7.14 (t, J = 8.0 Hz, 1H),
6.92 (t, J = 7.6 Hz, 1H), 6.66 (d, J = 8.0 Hz, 1H), 6.07(s, 1H),
4.82 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 163.0, 144.9, 142.3,
140.5, 134.2, 132.2, 130.5, 130.0, 129.2, 127.1, 126.9, 125.5,
123.0, 120.1, 117.1, 115.2, 74.0; HRMS Calcd for C20H16BrN2O
(M + H+): 379.0441; Found: 379.0444.
dihydroquinazolin-4(1H)-one (7a)
1
White soild. Mp: 146.3-148.4 °C; H NMR (400 MHz, CDCl3)
δ 8.02 (d, J = 7.6 Hz, 1H), 7.32-7.26 (m, 3H), 7.22-7.16 (m, 4H),
6.94-6.87 (m, 3H), 6.80 (d, J = 8.4 Hz, 1H), 6.63 (d, J = 8.0 Hz,
1H), 6.06 (s, 1H), 4.82 (s, 1H), 3.70 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 163.2, 159.9, 145.4, 141.5, 140.6, 134.0, 129.9, 129.1,
129.0, 127.1, 127.0, 119.8, 119.2, 116.9, 114.9, 114.5, 112.5,
74.7, 55.4; HRMS Calcd for C21H19N2O2 (M + H+): 331.1441;
Found: 331.1444.
4.3.24. 2-(2-Bromophenyl)-3-phenyl-2,3-
dihydroquinazolin-4(1H)-one (13a)
1
White soild. Mp: 135.3-137.4 °C; H NMR (400 MHz, CDCl3)
4.3.18. 2-(2-Methoxyphenyl)-3-phenyl-2,3-
δ 8.03 (d, J = 7.6 Hz, 1H), 7.57 (dd, J = 12.0, 8.0 Hz, 2H), 7.36-
7.30 (m, 2H), 7.27-7.21 (m, 5H), 7.16 (t, J = 8.0 Hz, 1H), 6.86 (t,
J = 7.6 Hz, 1H), 6.58 (d, J = 8.0 Hz, 1H), 6.39 (s, 1H), 5.36 (brs,
1H); 13C NMR (100 MHz, CDCl3) δ 163.5, 144.7, 140.8, 138.2,
134.2, 133.7, 130.5, 129.1, 129.0, 128.5, 128.0, 126.9, 125.9,
121.6, 119.7, 116.6, 115.0, 73.3; HRMS Calcd for C20H16BrN2O
(M + H+): 379.0441; Found: 379.0443.
dihydroquinazolin-4(1H)-one (8a)
1
White soild. Mp: 144.8-146.1 °C; H NMR (400 MHz, CDCl3)
δ 8.01 (d, J = 7.6 Hz, 1H), 7.43 (d, J = 7.6 Hz, 1H), 7.35-7.32 (m,
4H), 7.24-7.18 (m, 3H), 6.91-6.86 (m, 2H), 6.81 (t, J = 7.6 Hz,
1H), 6.54 (d, J = 8.0 Hz, 1H), 6.35 (s, 1H), 5.13 (s, 1H), 3.90 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 163.7, 155.9, 145.9, 141.3,
133.9, 129.9, 129.1, 128.9, 127.6, 127.5, 126.4, 125.7, 120.8,
119.3, 116.7, 115.0, 110.7, 69.9, 55.6; HRMS Calcd for
C21H19N2O2 (M + H+): 331.1441; Found: 331.1444.
4.3.25. 2-(4-Nitrophenyl)-3-phenyl-2,3-
dihydroquinazolin-4(1H)-one (14a)
Yellow soild. Mp: 173.8-177.1 °C; 1H NMR (400 MHz,
CDCl3) δ 8.13 (d, J = 8.4 Hz, 2H), 8.04 (d, J = 7.6 Hz,1H), 7.56
(d, J = 8.4 Hz, 2H), 7.37-7.30 (m, 3H), 7.21-7.19 (m, 2H), 7.01
(d, J = 8.8 Hz, 1H), 6.95 (t, J = 7.6 Hz, 1H), 6.70 (d, J = 8.0 Hz,
1H), 6.22 (s, 1H), 4.85 (s, 1H); 13C NMR (100 MHz, CDCl3) δ
162.8, 148.3, 146.9, 144.6, 140.4, 137.2, 134.4, 129.4, 128.0,
127.4, 126.7, 124.2, 120.7, 117.4, 115.6, 73.8; HRMS Calcd for
C20H16N3O3 (M + H+): 346.1184; Found: 346.1186.
4.3.19. 2-(4-Fluorophenyl)-3-phenyl-2,3-
dihydroquinazolin-4(1H)-one (9a)
1
White solid. Mp: 221.8-223.2 °C; H NMR (400 MHz, CDCl3)
δ 7.94 (d, J = 7.6 Hz, 1H), 7.47-7.44 (m, 1H), 7.28-7.18 (m, 4H),
7.12-7.04 (m, 3H), 6.88-6.80 (m, 3H), 6.56 (d, J = 8.0 Hz, 1H),
6.02 (s, 1H), 5.05 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ 164.2,
163.3, 161.8, 147.2, 145.4, 140.4, 139.4, 135.3, 134.1, 129.1,
129.0, 127.2, 127.1, 125.1, 119.9, 119.2, 115.9, 115.7, 115.0,
74.1; HRMS Calcd for C20H16FN2O (M + H+): 319.1241; Found:
319.1243.
4.3.26. Methyl 4-(4-oxo-3-phenyl-1,2,3,4-
tetrahydroquinazolin-2-yl)benzoate (15a)
1
White solid. Mp: 180.8-182.2 °C; H NMR (400 MHz, CDCl3)
4.3.20. 2-(4-Chlorophenyl)-3-phenyl-2,3-
δ 7.90 (d, J = 7.6 Hz, 1H), 7.82 (d, J = 8.0 Hz, 2H), 7.33 (d, J =
8.0 Hz, 2H), 7.22-7.17 (m, 3H), 7.10-7.08 (m, 3H), 6.78 (t, J =
7.6 Hz, 1H), 6.53 (d, J = 8.0 Hz, 1H), 6.00 (s, 1H), 5.13 (s, 1H),
3.79 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 166.6, 163.1, 145.2,
144.8, 140.5, 134.2, 130.7, 130.1, 129.2, 129.1, 127.1, 126.9,
126.8, 119.8, 116.8, 115.2, 74.1, 52.3; HRMS Calcd for
C22H19N2O3 (M + H+): 359.1390; Found: 359.1392.
dihydroquinazolin-4(1H)-one (10a)
1
White solid. Mp: 201.2-203.2 °C; H NMR (400 MHz, CDCl3)
δ 7.93 (dd, J = 7.6, 1.2 Hz, 1H), 7.25-7.19 (m, 5H), 7.16-7.08 (m,
5H), 6.82 (t, J = 7.6 Hz, 1H), 6.56 (d, J = 8.0 Hz, 1H), 5.99 (s,
1H), 4.81 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ 163.1, 145.2,
140.5, 138.6, 135.0, 134.1, 129.2, 129.1, 128.4, 127.1, 126.9,
123.0, 120.0, 117.1, 115.2, 74.1; HRMS Calcd for C20H16ClN2O
(M + H+): 335.0946; Found: 335.0948.
4.3.27. 4-(4-Oxo-3-phenyl-1,2,3,4-
tetrahydroquinazolin-2-yl)benzonitrile (16a)
1
4.3.21. 2-(4-Bromophenyl)-3-phenyl-2,3-
White solid. Mp: 202.4-204.6 °C; H NMR (400 MHz, CDCl3)
dihydroquinazolin-4(1H)-one (11a)
δ 7.90 (d, J = 7.6 Hz, 1H), 7.46-7.44 (m, 2H), 7.39-7.38 (m, 2H),
7.24-7.19 (m, 3H), 7.14-7.08 (m, 3H), 6.82 (t, J = 7.2 Hz, 1H),
6.57 (d, J = 8.0 Hz, 1H), 6.03 (s, 1H), 5.17 (s, 1H); 13C NMR
(100 MHz, CDCl3) δ 162.9, 145.0, 144.8, 140.3, 134.3, 132.6,
129.3, 129.0, 127.6, 127.2, 126.6, 120.1, 118.3, 116.8, 115.4,
112.8, 73.7; HRMS Calcd for C12H16N3O (M + H+): 326.1288;
Found: 326.1285.
1
White solid. Mp: 224.3-226.1 °C; H NMR (400 MHz, CDCl3)
δ 7.92 (dd, J = 8.0, 1.2 Hz, 1H), 7.31-7.29 (m, 2H), 7.25-7.21 (m,
2H), 7.20-7.09 (m, 6H), 6.82 (t, J = 7.6 Hz, 1H), 6.55 (d, J = 8.0
Hz, 1H), 5.97 (s, 1H), 4.84 (brs, 1H); 13C NMR (100 MHz,
CDCl3) δ 163.1, 145.1, 140.5, 139.1, 134.2, 132.0, 129.2, 129.1,
128.6, 127.1, 126.9, 123.1, 120.0, 117.1, 115.2, 74.1; HRMS
Calcd for C20H16BrN2O (M + H+): 379.0441; Found: 379.0440.
4.3.28. 3-Phenyl-2-(4-(trifluoromethyl)phenyl)-2,3-
dihydroquinazolin-4(1H)-one (17a)
4.3.22. 2-(4-Bromophenyl)-3-(furan-2-ylmethyl)-
1
2,3-dihydroquinazolin-4(1H)-one (11b)
White solid. Mp: 213.8-235.2 °C; H NMR (400 MHz, CDCl3)
δ 7.92 (dd, J = 7.6, 1.2 Hz, 1H), 7.44-7.38 (m, 4H), 7.24-7.18 (m,
3H), 7.13-7.10 (m, 3H), 6.81 (t, J = 7.6 Hz, 1H), 6.55 (d, J = 8.0
1
White solid. Mp: 183.3-185.3 °C; H NMR (400 MHz, CDCl3)
δ 7.96 (d, J = 7.6 Hz, 1H), 7.46-7.44 (m, 2H), 7.30 (s, 1H), 7.25-

9
Hz, 1H), 6.02 (s, 1H), 5.11 (brs, 1H); 13C NMR (100 MHz,
CDCl3) δ 163.0, 145.0, 144.0, 140.6, 134.3, 129.3, 129.1, 127.2,
127.1, 126.7, 125.9, 125.8, 125.8, 125.7, 120.0, 117.0, 115.4,
73.9; HRMS Calcd for C21H16F3N2O (M + H+): 369.1209; Found:
369.1206.
4.75 (brs, 1H), 1.68-1.61 (m, 2H), 1.44-1.40 (m, 2H), 1.28-1.26
(m, 4H), 0.88 (t, J = 6.8 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ
164.0, 144.5, 138.2, 133.6, 130.5, 129.2, 129.1, 128.1, 119.4,
117.4, 115.3, 73.5, 35.2, 32.1, 29.8, 29.7, 24.5, 22.6, 14.2;
HRMS Calcd for C19H21N2O (M + H+): 293.1648; Found:
293.1650.
4.3.29. 2-(Naphthalen-1-yl)-3-phenyl-2,3-
dihydroquinazolin-4(1H)-one (18a)
4.3.35. 6-Methyl-2,3-diphenyl-2,3-
1
dihydroquinazolin-4(1H)-one (25a)
White solid. Mp: 221.8-223.2 °C; H NMR (400 MHz, CDCl3)
1
δ 8.22 (d, J = 8.0 Hz, 1H), 8.00 (d, J = 8.0 Hz, 1H), 7.77 (d, J =
8.0 Hz, 1H), 7.68 (d, J = 8.0 Hz, 1H), 7.53 (d, J = 7.2 Hz, 1H),
7.49-7.40 (m, 3H), 7.24 (t, J = 8.0 Hz, 1H), 7.17-7.10 (m, 3H),
7.08-7.04 (m, 1H), 7.00-6.96 (m, 1H), 6.81-6.77 (m, 2H), 6.41 (d,
J = 8.0 Hz, 1H), 5.05 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ
164.2, 145.6, 140.5, 135.3, 134.3, 134.1, 133.5, 130.1, 129.9,
129.4, 129.2, 128.8, 126.9, 126.7, 126.2, 126.1, 125.2, 125.1,
119.8, 116.6, 115.2, 72.8; HRMS Calcd for C24H19N2O (M + H+):
351.1492; Found: 351.1494.
White solid. Mp: 165.1-167.3 °C; H NMR (400 MHz, CDCl3)
δ 7.74 (s, 1H), 7.26 (brs, 2H), 7.17 (brs, 5H), 7.12-7.01 (m, 3H),
6.81 (t, J = 6.8 Hz, 1H), 6.46 (d, J = 7.6 Hz, 1H), 5.96 (s, 1H),
4.20 (s, 1H), 2.19 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 163.4,
143.1, 140.9, 140.1, 134.9, 129.0, 129.0, 128.9, 128.8, 126.9,
126.8, 126.7, 117.3, 115.4, 112.8, 74.7, 20.7; HRMS Calcd for
C21H19N2O (M + H+): 315.1492; Found: 315.1495.
4.3.36. 8-Methoxy-2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one (26a)
1
4.3.30. 3-Phenyl-2-(pyridin-3-yl)-2,3-
White solid. Mp: 193.3-197.1 °C; H NMR (400 MHz, CDCl3)
dihydroquinazolin-4(1H)-one (19a)
δ 7.56 (d, J = 8.0 Hz, 1H), 7.31-7.29 (m, 2H), 7.20-7.19 (m, 5H),
7.12-7.10 (m, 3H), 6.81 (d, J = 7.6 Hz, 1H), 6.74 (t, J = 7.6 Hz,
1H), 6.09 (s, 1H), 5.14 (s, 1H), 3.75 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 163.3, 146.2, 140.7, 140.1, 136.2, 129.1, 129.0, 128.8,
127.3, 127.0, 126.9, 120.5, 118.4, 116.5, 113.5, 74.9, 55.8;
HRMS Calcd for C21H19N2O2 (M + H+): 331.1441; Found:
331.1444.
1
White solid. Mp: 227.5-229.2 °C; H NMR (400 MHz, CDCl3)
δ 8.49 (d, J = 2.0 Hz, 1H), 8.44 (dd, J = 4.8, 1.6 Hz, 1H), 7.95
(dd, J = 7.6, 1.2 Hz, 1H), 7.68 (dt, J = 8.0, 1.6 Hz, 1H), 7.28-7.19
(m, 3H), 7.15-7.10 (m, 4H), 6.85 (t, J = 7.6 Hz, 1H), 6.61 (d, J =
8.0 Hz, 1H), 6.10 (s, 1H), 4.91 (brs, 1H); 13C NMR (100 MHz,
CDCl3) δ 163.0, 150.3, 148.5, 145.0, 140.3, 135.6, 134.6, 134.3,
129.4, 127.3, 127.0, 125.2, 123.8, 120.3, 117.2, 115.4, 72.7;
HRMS Calcd for C19H16N3O (M + H+): 302.1288; Found:
302.1289.
4.3.37. 8-Methoxy-3-octyl-2-(4-
(trifluoromethyl)phenyl)-2,3-dihydroquinazolin-
4(1H)-one (26b)
1
4.3.31. 3-Phenyl-2-(pyridin-2-yl)-2,3-
White oil. H NMR (400 MHz, CDCl3) δ 7.60-7.56 (m, 3H),
dihydroquinazolin-4(1H)-one (20a)
7.50-7.48 (m, 2H), 6.83-6.76(m, 2H), 5.85 (s, 1H), 5.04 (s, 1H),
4.07-4.00 (m, 1H), 3.77 (s, 3H), 2.76-2.69 (m, 1H), 1.65-1.52 (m,
2H), 1.23 (s, 10H), 0.86 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3) δ 163.0, 146.0, 144.3, 135.0, 126.8, 126.1, 126.1, 126.0,
126.0, 120.0, 118.5, 116.0, 115.4, 113.3, 71.5, 55.8, 45.2, 31.9,
29.4, 29.3, 27.8, 27.0, 22.7, 14.2; HRMS Calcd for C24H30F3N2O2
(M + H+): 435.2254; Found: 435.2256.
1
White solid. Mp: 221.8-223.2 °C; H NMR (400 MHz, CDCl3)
δ 8.48 (d, J = 4.8 Hz, 1H), 7.91 (d, J = 7.6 Hz, 1H), 7.53 (t, J =
7.6 Hz, 1H), 7.43 (d, J = 8.0 Hz, 1H), 7.28-7.23 (m, 3H), 7.16-
7.09 (m, 4H), 6.74 (t, J = 7.6 Hz, 1H), 6.53 (d, J = 8.0 Hz, 1H),
6.00 (s, 1H), 5.05 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ 163.0,
159.0, 149.8, 145.6, 141.1, 137.2, 134.0, 129.1, 129.0, 126.5,
125.5, 123.5, 121.2, 119.6, 117.0, 115.3, 74.4; HRMS Calcd for
C19H16N3O (M + H+): 302.1288; Found: 302.1286.
4.3.38. 6,7-Dimethoxy-2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one (27a)
1
4.3.32. 3-Phenyl-2-(thiophen-2-yl)-2,3-
White solid. Mp: 138.3-140.3 °C; H NMR (400 MHz, CDCl3)
dihydroquinazolin-4(1H)-one (22a)
δ 7.67 (s, 1H), 7.32-7.19 (m, 9H), 6.76 (d, J = 8.0 Hz, 1H), 6.54
(d, J = 8.0 Hz, 1H), 6.04 (s, 1H), 5.41 (brs, 1H), 4.00 (s, 6H); 13C
NMR (100 MHz, CDCl3) δ 161.7, 154.4, 146.8, 143.8, 139.5,
130.3, 129.5, 128.9, 128.7, 127.6, 126.5, 112.8, 108.3, 106.1,
99.1, 74.7, 56.5, 56.4; HRMS Calcd for C22H21N2O3 (M + H+):
361.1547; Found: 361.1549.
1
White soild. Mp: 127.3-129.4 °C; H NMR (400 MHz, CDCl3)
δ 8.02 (d, J = 7.6 Hz, 1H), 7.34 (t, J = 7.6 Hz, 3H), 7.29-7.24 (m,
3H), 7.15 (d, J = 4.8 Hz, 1H), 6.94 (d, J = 8.0 Hz, 1H), 6.91 (d, J
= 3.6 Hz, 1H), 6.82 (t, J = 4.0 Hz, 1H), 6.70 (d, J = 8.0 Hz, 1H),
6.30 (s, 1H), 5.12 (brs, 1H); 13C NMR (100 MHz, CDCl3) δ 162.5,
145.0, 143.7, 140.5, 134.0, 129.2, 129.1, 127.2, 127.0, 126.8,
126.5, 126.1, 120.3, 117.4, 115.6, 71.0; HRMS Calcd for
C18H15N2OS (M + H+): 307.0900; Found: 307.0903.
4.3.39. 6-Fluoro-2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one (28a)
1
White solid. Mp: 177.3-179.3 °C; H NMR (400 MHz, CDCl3)
4.3.33. 2-Methyl-2,3-diphenyl-2,3-
δ 7.69 (dd, J = 8.8, 2.8 Hz, 1H), 7.35-7.33 (m, 2H), 7.29-7.25 (m,
5H), 7.19-7.15 (m, 3H), 7.00 (td, J = 8.8, 2.8 Hz, 1H), 6.59 (dd, J
= 8.8, 4.0 Hz, 1H), 6.05 (s, 1H), 4.91 (brs, 1H); 13C NMR (100
MHz, CDCl3) δ 162.5, 162.4, 158.1, 155.7, 141.7, 141.6, 140.5,
139.6, 129.1, 129.0, 128.8, 127.0, 126.9, 126.8, 121.5, 121.3,
118.5, 118.4, 117.0, 116.9, 114.9, 114.6, 74.7; HRMS Calcd for
C20H26FN2O (M + H+): 319.1241; Found: 319.1244.
dihydroquinazolin-4(1H)-one (23a)
1
White solid. Mp: 161.3-163.3 °C; H NMR (400 MHz, CDCl3)
δ 7.95 (d, J = 7.6 Hz, 1H), 7.54 (d, J = 6.4 Hz, 2H), 7.30-7.19 (m,
8H), 7.05 (brs, 2H), 6.84 (t, J = 7.6 Hz, 1H), 6.59 (d, J = 8.0 Hz,
1H), 1.89 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 163.9, 145.1,
143.6, 138.9, 133.9, 130.0, 129.2, 128.8, 128.6, 128.4, 127.6,
126.7, 119.4, 116.4, 114.6, 76.6, 27.7; HRMS Calcd for
C21H19N2O (M + H+): 315.1492; Found: 315.1490.
4.3.40. 3-Benzyl-6-fluoro-2-(p-tolyl)-2,3-
dihydroquinazolin-4(1H)-one (29a)
1
4.3.34. 3'-Phenyl-1'H-spiro[cyclohexane-1,2'-
White solid. Mp: 138.3-140.3 °C; H NMR (400 MHz, CDCl3)
quinazolin] -4'(3'H)-one (24a)
δ 7.68 (d, J = 8.4 Hz, 1H), 7.31-7.27 (m, 3H), 7.21-7.19 (m, 2H),
7.15-7.10 (m, 4H), 6.98-6.94 (m, 1H), 6.47 (dd, J = 8.8, 4.0 Hz,
1H), 5.59-5.53 (m, 2H), 4.55 (brs, 1H), 3.66 (d, J = 15.2 Hz, 1H),
2.32 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 162.6, 157.8, 157.7,
Yellow soild. Mp: 111.8-113.1 °C; 1H NMR (400 MHz,
CDCl3) δ 7.95 (d, J = 7.6 Hz, 1H), 7.44-7.31 (m, 4H), 7.23 (d, J =
7.2 Hz, 2H), 6.87 (t, J = 7.6 Hz, 1H), 6.74 (d, J = 8.0 Hz, 1H),

10
Tetrahedron
155.5, 155.4, 141.6, 141.5, 139.4, 136.7, 136.1, 129.7, 128.7,
128.1, 127.6, 126.6, 121.1, 120.9, 117.1, 117.0, 116.9, 116.1,
116.0, 114.7, 114.5, 71.0, 47.1, 21.3; HRMS Calcd for
C22H20FN2O (M + H+): 347.1554; Found: 347.1557.
HRMS Calcd for C22H27N2O (M + H+): 335.2118; Found:
335.2119.
Acknowledgments
4.3.41. 6-Chloro-2,3-diphenyl-2,3-
Financial Support from the Suzhou Science and Technology
Project (Grant No. SNG201620) and Qinglan Project of Jiangsu
Province of China is acknowledged.
dihydroquinazolin-4(1H)-one (30a)
1
White solid. Mp: 193.3-197.1 °C; H NMR (400 MHz, CDCl3)
δ 7.87 (s, 1H), 7.27-7.23 (m, 2H), 7.20-7.18 (m, 6H), 7.10-7.08
(m, 3H), 6.46 (dd, J = 8.4, 4.0 Hz, 1H), 5.96 (s, 1H), 5.04 (s, 1H);
13C NMR (100 MHz, CDCl3) δ 162.2, 143.9, 140.4, 139.6, 133.9,
129.2, 129.1, 128.9, 128.5, 127.1, 126.9, 126.8, 124.6, 119.0,
116.6, 74.6; HRMS Calcd for C20H16ClN2O (M + H+): 335.0946;
Found: 335.0949.
References and notes
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4665.
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4.3.42. 7-Chloro-3-cyclohexyl-2-(4-fluorophenyl)-
2,3-dihydroquinazolin-4(1H)-one (31a)
1
White soild. Mp: 105.3-107.4 °C; H NMR (400 MHz, CDCl3)
δ 7.87 (d, J = 8.4 Hz, 1H), 7.28-7.25 (m, 2H), 6.96 (t, J = 8.4 Hz,
2H), 6.79 (d, J = 8.4 Hz, 1H), 6.48 (s, 1H), 5.75 (s, 1H), 4.85 (s,
1H), 4.56-4.50 (m, 1H), 1.83-1.79 (m, 2H), 1.68-1.53 (m, 4H),
1.45-1.38 (m, 1H), 1.31-1.26 (m, 1H), 1.07-0.94 (m, 2H); 13C
NMR (100 MHz, CDCl3) δ 164.1, 161.9, 161.6, 144.9, 139.3,
137.9, 137.8, 130.1, 127.5, 127.4, 120.0, 116.1, 116.0, 115.8,
114.7, 67.0, 53.8, 31.3, 31.1, 26.0, 25.9, 25.5; HRMS Calcd for
C20H21ClFN2O (M + H+): 359.1321; Found: 359.1325.
4.3.43. 6-Bromo-2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one (32a)
1
White solid. Mp: 228.8-229.2 °C; H NMR (400 MHz, CDCl3)
δ 8.04 (s, 1H), 7.30-7.19 (m, 9H), 7.13-7.08 (m, 2H), 6.44 (dd, J
= 8.0, 3.2 Hz, 1H), 5.99 (s, 1H), 4.90 (brs, 1H); 13C NMR (100
MHz, CDCl3) δ 162.0, 144.3, 140.4, 139.6, 136.7, 131.6, 129.3,
129.1, 128.9, 127.1, 126.9, 126.8, 118.4, 116.9, 111.6, 74.6;
HRMS Calcd for C20H16BrN2O (M + H+): 379.0441; Found:
379.0443.
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4.3.44. 1-Methyl-2,3-diphenyl-2,3-
dihydroquinazolin-4(1H)-one (33a)
1
White solid. Mp: 163.3-167.1 °C; H NMR (400 MHz, CDCl3)
δ 8.00 (d, J = 7.6 Hz, 1H), 7.31 (t, J = 7.6 Hz, 1H), 7.27-7.21 (m,
2H), 7.19-7.17 (m, 3H), 7.13-711 (m, 5H), 6.82 (t, J = 7.6 Hz,
1H), 6.50 (d, J = 8.4 Hz, 1H), 5.71 (s, 1H), 2.85 (s, 3H); 13C
NMR (100 MHz, CDCl3) δ 162.4, 146.5, 140.9, 137.6, 134.3,
129.2, 129.2, 129.1, 128.8, 127.2, 127.0, 126.5, 118.7, 117.3,
112.6, 81.7, 36.5; HRMS Calcd for C21H19N2O (M + H+):
315.1492; Found: 315.1494.
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4.3.45. 2-(4-Chlorophenyl)-1-methyl-3-phenethyl-
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2,3-dihydroquinazolin-4(1H)-one (33b)
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White oil; H NMR (400 MHz, CDCl3) δ 8.02 (d, J = 7.6 Hz,
1H), 7.35-7.19 (m, 8H), 7.03 (d, J = 8.4 Hz, 2H), 6.86 (t, J = 7.6
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Supplementary Material
Supplementary data (copies of the 1H and 13C NMR spectra of
all products) associated with this article can be found at
http://dx.doi.org/XXXXXXXXXXXX.
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Microwave-promoted one-pot three-component synthesis of
2,3-dihydroquinazolin-4(1H)-ones catalyzed by
heteropolyanion-based ionic liquids under solvent-free conditions
Yang Yang, Renzhong Fu , Yang Liu, Jing Cai, Xiaojun Zeng
Jiangsu Laboratory of Advanced Functional Material, School of Materials Engineering, Changshu Institute of Technology,
Changshu 215500, China
Highlights:
2,3-Dihydroquinazoline-4(1H)-one derivatives have been synthesized via one-pot three-component reaction
catalyzed by heteropolyanion-based ionic liquids under solvent-free and microwave-promoted conditions.
Wide substrate scope, moderate to excellent yields, solvent-free media and operational simplicity are the
main highlights. The catalyst can be recovered and reused.
Corresponding author. Tel.: +86-512-52251842; fax: +86-512-52251842; e-mail: renzhongfujs@126.com

Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships
that could have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered
as potential competing interests: