Iodine-catalyzed synthesis of 2-arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives in ionic liquids via domino reaction

Article abstract of DOI:10.1016/j.tet.2014.03.075

The domino reaction of (E)-2-amino-N′-(1-arylethylidene) benzohydrazide and triethyl orthoformate in ionic liquids catalyzed by 10 mol % iodine gave 3a,4-dihydro-2-arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives unexpectedly. In the presence of K

Full text of DOI:10.1016/j.tet.2014.03.075

Accepted Manuscript
Iodine-Catalyzed Synthesis of 2-Arylpyrazolo[5,1-b]quinazolin-9(3H)-one Derivatives
in Ionic Liquids via Domino Reaction
Yu-Jing Zhou, Mei-Mei Zhang, Yu-Ling Li, Yun Liu, Xiang-Shan Wang
PII:
S0040-4020(14)00423-2
10.1016/j.tet.2014.03.075
TET 25416
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 16 December 2013
Revised Date: 18 March 2014
Accepted Date: 24 March 2014
Please cite this article as: Zhou Y-J, Zhang M-M, Li Y-L, Liu Y, Wang X-S, Iodine-Catalyzed Synthesis of
2-Arylpyrazolo[5,1-b]quinazolin-9(3H)-one Derivatives in Ionic Liquids via Domino Reaction, Tetrahedron
(2014), doi: 10.1016/j.tet.2014.03.075.
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ACCEPTED MANUSCRIPT
Iodine-Catalyzed Synthesis of 2-Arylpyrazolo[5,1-b]quinazolin-9(3H)-one
Derivatives in Ionic Liquids via Domino Reaction
Yu-Jing Zhou, Mei-Mei Zhang, Yu-Ling Li, Yun Liu, Xiang-Shan Wang*
The Domino reaction of (E)-2-amino-N'-(1-arylethylidene)benzohydrazide and triethyl
orthoformate in ionic liquids catalyzed by 10 mol% iodine gave 3a,4-dihydro-2-
arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives unexpectedly. In the presence of K2S2O8, it
could be oxidized to aromatized products in good yields.
O
N
N
10 mol% I2
Ar
Ar
O
N
H
3
N
Ar
R
N
R = H
H
CH(OEt)3
2
+
NH2
O
N
10 mol% I2
K2S2O8
1
N
N
H
R
4
1

ACCEPTED MANUSCRIPT
Iodine-Catalyzed Synthesis of 2-Arylpyrazolo[5,1-b]quinazolin-9(3H)-one
Derivatives in Ionic Liquids via Domino Reaction
Yu-Jing Zhou, Mei-Mei Zhang, Yu-Ling Li, Yun Liu, Xiang-Shan Wang*
School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthsis for
Functional Materials, Jiangsu Normal University, Xuzhou Jiangsu 221116, P. R. China
Fax: (+0086-516-83500065)
E-mail: xswang1974@yahoo.com
Abstract. The Domino reaction of (E)-2-amino-N'-(1-arylethylidene)benzohydrazide and triethyl
orthoformate in ionic liquids catalyzed by 10 mol% iodine gave 3a,4-dihydro-2-arylpyrazolo
[5,1-b]quinazolin-9(3H)-one derivatives unexpectedly. In the presence of K2S2O8, it could be
oxidized to aromatized products in good yields.
Keywords: pyrazoloquinazoline; Domino reaction; iodine; synthesis
Introduction
Pyrazoloquinazoline moiety is a fused tricyclic heterocycle, and its derivatives are
an important class of molecules with physiological significance and pharmaceutical
utility. A well-known example is 7-(benzolylamino)-4,9-dihydro-4-methyl-9-oxo
pyrazolo[5,1-b]quinazoline-2-carboxylic acid (Figure 1), which was reported to be an
effective nerve growth factor antagonist.1 Its derivatives are usually used as various
kinds of inhibitors, such as PDE10A enzyme inhibitors,2 MPS1 kinase inhibitors,3
phosphodie-sterase 10A inhibitors,4 PDK1 inhibitors,5 and orally polo-like kinase 1
2

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inhibitors.6 They are also used in treating diseases caused by dysregulated protein
kinase activity and PIM kinases,7 or used in the treatment of mesothelioma as
ATP-competitive CDK inhibitor.8 Therefore, much attention has been devoted to the
synthesis of these bioactive pyrazoloquinazoline derivatives.9-13 The existing methods
for these derivatives are three-component condensation of 5-aminopyrazoles,
dimedone, and aldehydes,9 the reaction of 2-(1-hydropolyfluoro-1-alkenyl)-4H-3,1-
benzoxin-4-ones with hydrazine hydrate and phenylhydrazine,10 or the condensation
of
α
-cyanoketones and 2-hydrazinobenzoic acids.11
O
H
N
N
N
CO2H
O
N
Figure 1. The active molecule containing pyrazoloquinazoline moiety
In our previous study, quinazolin-4(3H)-ones were obtained by the known reaction
of triethyl orthoformate and 2-aminobenzamide catalyzed by iodine in ionic liquids.14
In order to get structurally diversified quinazolin-4(3H)-ones, the reactant of
2-aminobenzamide was replaced by 2-amino-N'-(1-phenylethylidene)benzohydrazide
1a which reacts with triethyl orthoformate 2. It was found that a distinctly different
product of 3a,4-dihydro-2-phenylpyrazolo[5,1-b]quinazolin-9(3H)-one 3a was
obtained unexpectedly rather than 3-(1-phenylethylideneamino)quinazolin-4(3H)-one
(Scheme 1) with ring-closure. Herein, we would like to report the new Domino
ring-closure reaction catalyzed by iodine to build potentially bioactive
pyrazolo[5,1-b]quinazoline moiety.
3

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Results and Discussion
We repeated this novel reaction to optimize the conditions. Several parameters
including catalysts and solvents were explored as shown in Table 1. No desired
product was obtained when the reaction was carried out in the absence of iodine
(Table 1, Entry 1), and 52 % of the product was obtained with 5 mol% of iodine. A
maximum of 89 % yield was reached with 10 mol% iodine (Table 1, entries 2, 3, and
4). Other metal Lewis acids, such as AgOTf, Yb(OTf)3, TsOH were also tested in this
reaction (Table 1, entries 6–8), and no product of 3a was found by TLC. In addition,
different imidazoliums in ionic liquids and organic solvents, such as toluene, CH3CN,
THF DMF and DME were also tested, and [PMIm]Br appeared to be the best medium
for this transformation (entries 3 vs. 9-16).
O
N
Ph
N
O
N
N
Ph
N
10 mol% I2
H
CH(OEt)3
+
O
NH2
N
N
Ph
2
1a
N
H
3a
Scheme 1. The model reaction
Table 1. Synthesis of 3a under different reaction conditions a
Entry
Cat.
Solventb
Yieldsc/%
1
2
3
4
-
[PMIm]Br
[PMIm]Br
[PMIm]Br
[PMIm]Br
0
I2(5)
I2(10)
I2(20)
52
89
88
4

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5
CuI(10)
AgOTf(10)
Yb(OTf)3(10)
TsOH(10)
I2(10)
[PMIm]Br
[PMIm]Br
[PMIm]Br
[PMIm]Br
[EMIm]Br
[BMIm]Br
0
6
0
7
0
8
0
9
62
82
10
11
12
13
14
15
16
I2(10)
I2(10)
[PMIm][BF4] 80
I2(10)
Toluened
CH3CNd
THFd
DMFe
DMEe
trace
I2(10)
trace
trace
41
I2(10)
I2(10)
I2(10)
39
a
Reagents and conditions: 1a (0.253 g, 1.0 mmol), 2 (0.222 g, 1.5 mmol), organic solvent (10
b
mL). BMIm = 1-butyl-3-methylimidazolium; EMIm = 1-ethyl-3-methyl imidazolium; PMIm =
1-methyl-3-propylimidazolium, ionic liquids 2 mL, 80 °C. c Isolated yields. d reflux, e 100 °C.
Similarly, various kinds of 1 were submitted to react with 2 to give structurally
diversified 3a,4-dihydro-2-arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives 3a-o
in good yields (Scheme 2). The results are summarized in Table 2. It can be observed
that the process tolerates both electron-donating (such as alkyl and alkoxy) and
electron-withdrawing (such as halogen and nitro) substituents in the 1. In all cases, the
reactions proceeded efficiently at 80 °C under mild conditions to afford the
corresponding products in good to high yields. The structure of 3h was confirmed by
X-ray diffraction analysis, and its crystal structure is shown in Figure 2.
O
O
N
Ar
N
N
N
10 mol% I2
R
H
Ar
R
CH(OEt)3
+
NH2
N
H
2
3
1
Scheme 2. Synthetic route of 3
Table 2. The synthetic results for the products 3a
5

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Products Ar
R
Time /h
Yields b /%
3a
3b
3c
3d
3e
3f
Ph
H
12
10
10
15
12
15
10
14
10
13
13
12
12
10
10
89
85
85
90
83
78
86
84
89
80
85
78
89
86
82
4-ClC6H4
3-BrC6H4
4-CH3C6H4
4-BrC6H4
2-NH2C6H4
4-NO2C6H4
4-MeOC6H4
3,4-Cl2C6H3
4-n-BuC6H4
4-i-BuC6H4
2-Thienyl
Ph
H
H
H
H
H
3g
3h
3i
H
H
H
3j
H
3k
3l
H
H
3m
3n
3o
5-Me
5-Br
5-Cl
Ph
Ph
a Reagents and conditions: 1 (1.0 mmol), 2 (0.222 g, 1.5 mmol), I2 (25 mg, 0.1 mmol), [PMIm]Br
(2.0 mL). b Isolated yields.
Figure 2. The crystal structure of the product 3h
2-Amino-N'-(1-phenylpropylidene)benzohydrazide was also chosen as starting
material to react with triethyl orthoformate under the same reaction conditions. As we
expected, the designed reaction occurred smoothly but gave a mixture of cis- and
trans-3a,4-dihydro-3-methyl-2-phenylpyrazolo[5,1-b]quinazolin-9(4H)-one in 90 %
yield (31 : 69, Scheme 3), which was determined by 1H NMR. However, it should be
6

ACCEPTED MANUSCRIPT
noted that the mixture of cis- and trans-isomers was hard to separate although column
chromatography of silica gel was used.
O
O
O
N
Ph
N
N
N
N
H
N
10 mol% I2
Ph
H
2
Ph
+
+
NH2
N
H
N
H H
CH3
CH3
cis-
trans-
K2S2O8
O
N
N
Ph
N
H
CH3
4a
Scheme 3. Synthetic route of 4a
Subsequently, in order to obtain aromatized products, different oxidants, such as
DDQ, PhI(OAc)2 and K2S2O8, were used to promote dehydrogenation (Scheme 3). It
was found that K2S2O8 gave the best result in total of 79 % yield for 4a. In our
continued study, the product 4a could be obtained in 82 % by a one-pot reaction
without separation of intermediate. And then, different reactants of 1 were applied to
this first ring-closure reaction and then dehydrogenation reaction (Scheme 4), which
all reacted well to give 4a-k in good yields (Table 3).
O
O
N
Ar
R
N
N
N
1)
2)
10 mol% I2
K2S2O8
R'
Ar
H
R'
+
2
NH2
N
H
R
1
4
Scheme 4. Synthetic route of 4
Table 3. The synthetic results for the products 4a
7

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Prodocts Ar
R
R'
Time /h Yields b /%
4a
4b
4c
4d
4e
4f
Ph
CH3
CH3
CH3
CH3
CH3
CH3
H
H
H
H
H
H
H
H
H
18
20
21
20
19
25
21
23
82
75
76
85
75
86
79
80
76
76
81
3-ClC6H4
4-ClC6H4
4-CH3C6H4
4-FC6H4
4-OMeC6H4
4-CH3C6H4
Ph
4g
4h
4i
Et
Ph
Et
5-Me 24
4j
Ph
n-Pr 5-Br
n-Pr
22
20
4k
4-ClC6H4
H
a
Reagents and conditions: 1 (1.0 mmol), 2 (0.222g, 1.5 mmol), I2 (25 mg, 0.1 mmol), K2S2O8
(0.405g, 1.5 mmol), [PMIm]Br (2.0 mL). b Isolated yields.
According to the product structures, we think that the intermediate product 5 may
form by a condensation reaction first; and then, 5 is in equilibrium with its enamine
form 6 in the presence of iodine; the intra-molecular nucleophilic addition takes place
along with cyclization reaction at last to give final product 3. In the presence of
K2S2O8, it could be oxidized to aromatized product 4. The possible mechanism was
proposed as shown in Scheme 5.
O
O
N
Ar
N
Ar
N
H
I2
N
CH(OEt)3
+
NH2
N
2
1
5
H
O
O
N
O
N
N
Ar
N
N
K2S2O8
N
N
Ar
Ar
N
H
N
H
I2
4
6
3
Scheme 5. The possible mechanism
Conclusion
8

ACCEPTED MANUSCRIPT
In conclusion, we found a novel and efficient method for the Domino synthesis of
2-arylpyrazolo[5,1-b]quinazolin-9(3H)-one derivatives catalyzed by iodine in ionic
liquids. The subsequent dehydrogenation took place to give aromatized ones in good
yields using K2S2O8 as an oxidant.
Experimental Section
General procedure for the syntheses of 3a,4-dihydro-2-arylpyrazolo
[5,1-b]quinazolin-9(3H)-one derivatives 3
2-Amino-N'-(1-arylethylidene)benzohydrazide (1.0 mmol), triethyl orthoformate (222
mg, 1.5 mmol), I2 (25 mg), and [PMIm]Br (2 mL) were added into a 25 mL flask. The
reaction mixture was stirred at 80 °C for 10-15 h before completion, which was
monitored by TLC. A small amount of water (5 mL) was added to the mixture, and the
generated yellow solid was filtered off. The water in the filtrate was removed by
distillation under reduced pressure, and the ionic liquids in the residue could be
reusable by evaporating at 80 °C for 4 hours in vacuo. The crude yellow products
were washed with water and purified by recrystallization from 95 % EtOH to give 3.
2-Phenyl-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3a: Yield 89 % (234 mg).
1
Pale yellow solid, m.p.: 272~274 °C; H NMR (DMSO-d6, 400 MHz): δH 3.30 (dd, J
= 16.8 Hz, J’ = 10.0 Hz, 1H), 3.73 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 5.42 (t, J =
10.0 Hz, 1H), 6.88~6.94 (m, 2H), 7.39 (t, J = 7.6 Hz, 1H), 7.51~7.52 (m, 3H), 7.55 (s,
1H), 7.81 (d, J = 8.0 Hz, 1H), 7.83~7.84 (m, 2H). 13C NMR (DMSO-d6, 100 MHz): δc
39.5, 69.6, 115.4, 116.5, 118.9, 126.8, 128.0, 128.8, 130.6, 131.1, 133.3, 147.9, 156.7,
9

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157.1. IR (KBr):
ν
3300, 3052, 3031, 2095, 1651, 1578, 1559, 1481, 1440, 1415,
1330, 1315, 1302, 1258, 1239, 1196, 1177, 1153, 1116, 1050, 887, 858, 755, 688 cm-1.
HRMS (ESI, m/z): Calcd for C16H13N3ONa [M + Na]+ 286.0956, found 286.0953.
2-(4-Chlorophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3b: Yield 85
1
% (253 mg). Pale yellow solid, m.p.: 269~271 °C; H NMR (DMSO-d6, 400 MHz):
δH 3.30 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H), 3.74 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H),
5.41 (t, J = 10.0 Hz, 1H), 6.88~6.93 (m, 2H), 7.33~7.40 (m, 3H), 7.60 (s, 1H), 7.79
(d, J = 7.6 Hz, 1H), 7.87~7.91 (m, 2H). 13C NMR (DMSO-d6, 100 MHz): δc 39.5,
70.2, 115.9, 116.3, 116.5, 117.0, 119.4, 128.5, 129.7, 129.8, 133.8, 148.4, 156.8,
157.1. IR (KBr):
ν 3300, 3060, 3022, 2712, 1650, 1608, 1564, 1512, 1483, 1443,
1423, 1329, 1306, 1227, 1196, 1179, 1152, 1117, 1096, 1049, 1031, 1012, 982, 947,
886, 836, 811, 758, 686 cm-1. HRMS (ESI, m/z): Calcd for C16H12ClN3ONa [M +
Na]+ 320.0567, found 320.0562.
2-(3-Bromophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3c: Yield 85 %
1
(291 mg). Pale yellow solid, m.p.: 280~282 °C; H NMR (DMSO-d6, 400 MHz): δH
3.31 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.74 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H),
5.42 (t, J = 10.0 Hz, 1H), 6.88~6.94 (m, 2H), 7.37~7.41 (m, 1H), 7.47 (t, J = 8.0 Hz,
1H), 7.59 (s, 1H), 7.70 (d, J = 8.0 Hz, 1H), 7.79~7.84 (m, 2H), 7.98 (s, 1H). 13C NMR
(DMSO-d6, 100 MHz): δc 39.5, 70.3, 116.0, 116.8, 119.48, 119.52, 122.6, 126.3,
128.6, 129.6, 131.5, 133.6, 134.0, 148.5, 156.5, 157.2. IR (KBr):
ν 3265, 3036, 2955,
2926, 2856, 1658, 1632, 1575, 1495, 1481, 1434, 1325, 1271, 1265, 1162, 1115,
10

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1030, 936, 862, 831, 757, 690cm-1. HRMS (ESI, m/z): Calcd for C16H12BrN3ONa [M
+ Na]+ 364.0061, found 364.0048.
2-(p-Tolyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3d: Yield 90 % (249
1
mg). Pale yellow solid, m.p.: 250~252 °C; H NMR (DMSO-d6, 400 MHz): δH 2.37
(s, 3H), 3.27 (dd, J = 17.0 Hz, J’ = 10.0 Hz, 1H), 3.70 (dd, J = 17.0 Hz, J’ = 10.0 Hz,
1H), 5.90 (t, J = 10.0 Hz, 1H), 6.87~6.93 (m, 2H), 7.32 (d, J = 8.0 Hz, 2H), 7.36~7.40
(m, 1H), 7.55 (s, 1H), 7.73 (d, J = 8.4 Hz, 2H), 7.79 (d, J = 7.6 Hz, 1H). 13C NMR
(DMSO-d6, 100 MHz): δc 21.0, 39.5, 69.6, 115.4, 116.6, 118.9, 126.8, 128.0, 128.3,
129.4, 133.2, 140.5, 147.9, 156.6, 157.1. IR (KBr):
ν 3270, 3032, 2978, 2899, 2858,
1661, 1608, 1494, 1434, 1324, 1271, 1256, 1238, 1175, 1162, 1114, 1030, 935, 861,
816, 754, 688cm-1. HRMS (ESI, m/z): Calcd for C17H15N3ONa [M + Na]+ 300.1113,
found 300.1122.
2-(4-Bromophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3e: Yield 83 %
1
(284 mg). Pale yellow solid, m.p.: 280~282 °C; H NMR (DMSO-d6, 400 MHz): δH
3.30 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H), 3.71 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H),
5.41 (t, J = 10.0 Hz, 1H), 6.88~6.93 (m, 2H), 7.37~7.41 (m, 1H), 7.59 (s, 1H), 7.71
(d, J = 8.4 Hz, 2H), 7.76~7.80 (m, 3H). 13C NMR (DMSO-d6, 100 MHz): δc 39.6,
70.3, 115.9, 116.9, 119.5, 124.5, 128.5, 129.2, 130.8, 132.3, 133.9, 148.4, 156.8,
157.2. IR (KBr):
ν 3296, 3064, 2905, 2850, 1650, 1610, 1482, 1441, 1417, 1326,
1308, 1258, 1239, 1195, 1178, 1152, 1117, 1071, 1008, 861, 821, 756, 690 cm-1.
HRMS (ESI, m/z): Calcd for C16H12BrN3ONa [M + Na]+ 364.0061, found 364.0057.
11

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2-(2-Aminophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3f: Yield 78 %
(217 mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 3.38
(dd, J = 16.4 Hz, J’ = 9.6 Hz, 1H), 3.42 (brs. 2H), 3.85 (dd, J = 16.4 Hz, J’ = 9.6 Hz,
1H), 5.40 (t, J = 9.6 Hz, 1H), 6.66~6.70 (m, 1H), 6.87 (d, J = 8.0 Hz, 1H), 6.93~6.99
(m, 2H), 7.24 (t, J = 7.6 Hz, 1H), 7.38 (d, J = 8.0 Hz, 1H), 7.42~7.46 (m, 1H), 7.61 (s,
1H), 7.85 (d, J = 7.6 Hz, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 41.0, 68.6, 112.0,
115.5, 115.8, 115.9, 117.1, 119.4, 128.4, 130.6, 131.6, 133.7, 148.4, 148.6, 156.7,
159.3. IR (KBr):
ν 3419, 3308, 3199, 3078, 3035, 1662, 1612, 1573, 1541, 1498,
1479, 1441, 1342, 1327, 1270, 1197, 1161, 1011, 1032, 985, 934, 881, 823, 761, 745,
686 cm-1. HRMS (ESI, m/z): Calcd for C16H13N4O [M – H]- 277.1089, found
277.1104.
2-(4-Nitrophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3g: Yield 86 %
(265 mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 3.36
(dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H), 3.79 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H), 5.47 (t,
J = 10.0 Hz, 1H), 6.89~6.94 (m, 2H), 7.40 (t, J = 7.6 Hz, 1H), 7.64 (s, 1H), 7.80 (d, J
= 7.6 Hz, 1H), 8.08~8.08 (m, 2H), 8.32(d, J = 8.8 Hz, 2H). 13C NMR (DMSO-d6, 100
MHz): δc 39.5, 70.6, 116.0, 116.7, 119.5, 124.4, 128.4, 128.6, 134.2, 137.7, 148.5,
148.6, 156.0, 157.4. IR (KBr):
ν 3272, 3069, 3000, 2950, 2850, 1656, 1613, 1561,
1509, 1484, 1440, 1343, 1317, 1232, 1185, 1163, 1109, 1033, 938, 847, 789, 760,
689cm-1. HRMS (ESI, m/z): Calcd for C16H11N4O3Na [M + Na]+ 331.0807, found
331.0799.
12

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2-(4-Methoxyphenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3h: Yield 84
1
% (246 mg). Pale yellow solid, m.p.: 234~236 °C; H NMR (DMSO-d6, 400 MHz):
δH 3.25 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.69 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H),
3.83 (s, 3H), 5.37 (t, J = 10.0 Hz, 1H), 6.87~6.90 (m, 2H), 7.06 (d, J = 8.8 Hz, 2H),
7.36~7.40 (m, 1H), 7.55 (s, 1H), 7.77~7.80 (m, 3H). 13C NMR (DMSO-d6, 100
MHz): δc 39.8, 55.8, 70.0, 114.7, 115.8, 117.1, 119.4, 124.0, 128.5, 129.0, 133.7,
148.3, 157.0, 157.3, 161.6. IR (KBr):
ν 3257, 3000, 2954, 2907, 2833, 1642, 1606,
1515, 1486, 1437, 1331, 1304, 1255, 1173, 1117, 1032, 1017, 834, 794, 757, 690
cm-1. HRMS (ESI, m/z): Calcd for C17H15N3O2Na [M + Na]+ 316.1062, found
316.1066.
2-(3,4-Dichlorophenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3i: Yield
1
89 % (295 mg). Pale yellow solid, m.p.: 251~253 °C; H NMR (DMSO-d6, 400
MHz): δH 3.31 (dd, J = 17.2 Hz, J’ = 10.0 Hz, 1H), 3.74 (dd, J = 17.2 Hz, J’ = 10.0
Hz, 1H), 5.43 (t, J = 10.0 Hz, 1H), 6.88~6.94 (m, 2H), 7.37~7.41 (m, 1H), 7.61 (s,
1H), 7.72~7.81 (m, 3H), 8.00~8.01 (m, 1H). 13C NMR (DMSO-d6, 100 MHz): δc
39.5, 70.4, 116.0, 116.8, 119.5, 127.2, 128.6, 128.9, 131.6, 132.2, 132.3, 133.4, 134.0,
148.5, 155.8, 157.3. IR (KBr):
ν 3443, 3293, 2933, 2915, 1655, 1559, 1504, 1445,
1416, 1392, 1317, 1301, 1257, 1188, 1167, 1149, 1105, 1050, 894, 829, 757, 727, 688
cm-1. HRMS (ESI, m/z): Calcd for C16H10Cl2N3O [M – H]- 330.0201, found 330.0197.
2-(4-n-Butylphenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3j: Yield 80
1
% (255 mg). Pale yellow solid, m.p.: > 300 °C; H NMR (DMSO-d6, 400 MHz): δH
0.88~0.93 (m, 3H), 1.26~1.36 (m, 2H), 1.53~1.61 (m, 2H), 2.63 (t, J = 7.6 Hz, 2H),
13

ACCEPTED MANUSCRIPT
3.27 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.70 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H),
5.38 (t, J = 10.0 Hz, 1H), 6.88~6.93 (m, 2H), 7.32 (d, J = 8.0 Hz, 2H), 7.36~7.40 (m,
1H), 7.56 (s, 1H), 7.74 (d, J = 8.0 Hz, 2H), 7.79 (d, J = 7.6 Hz, 1H). 13C NMR
(DMSO-d6, 100 MHz): δc 14.2, 22.2, 33.4, 35.2, 39.5, 70.0, 115.9, 117.1, 119.4,
126.8, 127.3, 128.5, 129.2, 133.7, 145.8, 148.4, 157.1, 157.6. IR (KBr):
ν 3266, 3071,
3027, 2927, 2854, 1661, 1612, 1501, 1439, 1406, 1321, 1305, 1275, 1191, 1164,
1150, 1122, 1070, 1030, 995, 945, 887, 778, 749, 688cm-1. HRMS (ESI, m/z): Calcd
for C20H20N3O [M – H]- 318.1606, found 318.1603.
2-(4-iso-Butylphenyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3k: Yield 85
1
% (271 mg). Pale yellow solid, m.p.: 273~275 °C; H NMR (DMSO-d6, 400 MHz):
δH 0.87~0.90 (m, 8H), 1.82~1.92 (m, 1H), 3.28 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H),
3.71 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 5.39 (t, J = 10.0 Hz, 1H), 6.88~6.93 (m,
2H), 7.28~7.30 (m, 2H), 7.36~7.42 (m, 1H), 7.56 (s, 1H), 7.74~7.77 (m, 2H), 7.79 (d,
J = 7.6 Hz, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 22.6, 30.1, 39.5, 44.9, 70.1,
115.9, 117.1, 119.4, 126.7, 127.2, 128.5, 129.9, 133.7, 144.6, 148.4, 157.1, 157.6. IR
(KBr):
ν 3269, 3141, 3070, 3039, 2952, 2912, 2867, 1659, 1630, 1608, 1578, 1553,
1495, 1481, 1433, 1407, 1325, 1295, 1271, 1174, 1161, 1115, 936, 863, 843, 795, 784,
758 cm-1. HRMS (ESI, m/z): Calcd for C20H20N3O [M – H]- 318.1606, found
318.1611.
2-(2-Thienyl)-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3l: Yield 78 % (210
1
mg). Pale yellow solid, m.p.: 251~253 °C; H NMR (DMSO-d6, 400 MHz): δH 3.23
(dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.61 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 5.37 (t,
14

ACCEPTED MANUSCRIPT
J = 10.0 Hz, 1H), 6.71~6.72 (m, 1H), 6.87~6.92 (m, 2H), 7.11~7.12 (m, 1H), 7.38 (t,
J = 7.6 Hz, 1H), 7.55 (s, 1H), 7.78 (d, J = 8.0 Hz, 1H), 7.95 (s, 1H). 13C NMR
(DMSO-d6, 100 MHz): δc 39.5, 69.7, 112.9, 114.8, 115.9, 117.0, 119.5, 128.5, 133.8,
146.5, 146.8, 148.3, 148.7, 157.1. IR (KBr):
ν 3423, 3273, 3117, 3080, 2907, 2856,
1663, 1613, 1498, 1481, 1426, 1394, 1321, 1272, 1245, 1161, 1117, 1035, 1004, 939,
884, 760 cm-1. HRMS (ESI, m/z): Calcd for C14H10SN3O [M – H]- 268.0545, found
268.0551.
7-Methyl-2-phenyl-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3m: Yield 89
1
% (246 mg). Pale yellow solid, m.p.: 279~281 °C; H NMR (DMSO-d6, 400 MHz):
δH 2.32 (s, 3H), 3.34 (dd, J = 17.0 Hz, J’ = 10.0 Hz, 1H), 3.77 (dd, J = 17.0 Hz, J’ =
10.0 Hz, 1H), 5.41 (t, J = 10.0 Hz, 1H), 6.90 (d, J = 8.0 Hz, 1H), 7.27 (d, J = 8.0 Hz,
1H), 7.40~7.42 (m, 1H), 7.56~7.57 (m, 3H), 7.66 (s, 1H), 7.87~7.89 (m, 2H). 13C
NMR (DMSO-d6, 100 MHz): δc 20.6, 39.5, 70.3, 116.0, 117.0, 127.3, 128.3, 128.34,
129.3, 131.0, 131.6, 134.7, 146.2, 157.2, 157.5. IR (KBr):
ν 3443, 3424, 3293, 2933,
2915, 1655, 1504, 1445, 1416, 1392, 1332, 1317, 1257, 1188, 1167, 1149, 1105, 1050,
912, 894, 829, 757, 727, 688cm-1. HRMS (ESI, m/z): Calcd for C17H14N3O [M – H]-
276.1137, found 276.1146.
7-Bromo-2-phenyl-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3n: Yield 89 %
(294 mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 3.33
(dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.75 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 5.44 (t,
J = 10.0 Hz, 1H), 6.90 (d, J = 8.4 Hz, 1H), 7.51~7.54 (m, 4H), 7.82~7.84 (m, 4H). 13C
NMR (DMSO-d6, 100 MHz): δc 39.5, 70.0, 110.4, 118.2, 118.7, 127.4, 129.3, 130.4,
15

ACCEPTED MANUSCRIPT
131.3, 131.4, 136.3, 147.5, 155.9, 158.3. IR (KBr):
ν 3263, 3061, 2920, 2850, 1654,
1607, 1559, 1491, 1448, 1435, 1333, 1302, 1273, 1240, 1189, 1173, 1126, 1073, 858,
810, 755, 685 cm-1. HRMS (ESI, m/z): Calcd for C16H11BrN3O [M – H]- 340.0085,
found 340.0074.
5-Chloro-2-phenyl-3a,4-dihydropyrazolo[5,1-b]quinazolin-9(3H)-one 3o: Yield 82 %
(244 mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 3.30
(dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 3.75 (dd, J = 16.8 Hz, J’ = 10.0 Hz, 1H), 5.44 (t,
J = 10.0 Hz, 1H), 6.96 (d, J = 8.8 Hz, 1H), 7.42~7.44 (m, 1H), 7.51~7.53 (m, 3H),
7.72~7.73 (m, 1H), 7.79 (s, 1H), 7.83~7.85 (m, 2H). 13C NMR (DMSO-d6, 100
MHz): δc 39.5, 70.1, 117.9, 118.3, 123.1, 127.4, 127.5, 129.3, 131.2, 131.4, 133.5,
147.2, 156.0, 158.3. IR (KBr):
ν 3291, 3188, 3151, 3066, 2963, 2907, 1653, 1585,
1560, 1494, 1446, 1411, 1362, 1333, 1255, 1205, 1166, 1139, 1119, 1100, 1076, 1051,
998, 969, 945, 901, 861, 821, 760, 727, 688 cm-1. HRMS (ESI, m/z): Calcd for
C16H11ClN3O [M – H]- 296.0591, found 296.0590.
General
procedure
for
the
syntheses
of
2-arylpyrazolo[5,1-b]
quinazolin-9(4H)-one derivatives 4
2-Amino-N'-(1-arylethylidene)benzohydrazide (1.0 mmol), triethyl orthoformate (222
mg, 1.5 mmol), I2 (25 mg), and [PMIm]Br (2 mL) was added into a 25 mL flask. The
reaction mixture was stirred at 80 °C for 18-25 h before completion, which was
monitored by TLC. Then K2S2O8 (0.405g, 1.5 mmol) were added to the reaction, and
it was kept at the same reaction temperature until all the intermediates were consumed.
A small amount of water (5 mL) was added to the mixture, and the generated yellow
16

ACCEPTED MANUSCRIPT
solid was filtered off. The water in the filtrate was removed by distillation under
reduced pressure, and the ionic liquids in the residue could be reusable by evaporating
at 80 °C for 4 hours in vacuum. The crude yellow products were washed with water
and purified by recrystallization from 95 % EtOH to give 4.
3-Methyl-2-phenylpyrazolo[5,1-b]quinazolin-9(4H)-one 4a: Yield 82 % (225 mg).
1
Pale yellow solid, m.p.: > 300 °C; H NMR (DMSO-d6, 400 MHz): δH 2.33 (s, 3H),
7.25 (t, J = 7.6 Hz, 1H), 7.47~7.55 (m, 4H), 7.34~7.78 (m, 1H), 7.82 (d, J = 7.2 Hz,
2H), 8.20 (d, J = 8.0 Hz, 1H), 11.90 (s, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 8.6,
93.8, 112.0, 116.4, 121.6, 128.0, 128.4, 129.07, 129.11, 133.5, 135.0, 140.4, 141.0,
154.8, 156.0. IR (KBr):
ν 3285, 3207, 3132, 3092, 3059, 3007, 2976, 2929, 2885,
1639, 1578, 1509, 1492, 1474, 1439, 1428, 1337, 1308, 1271, 1224, 1208, 1181,
1125, 1015, 946, 775, 749, 701 cm-1. HRMS (ESI, m/z): Calcd for C17H12N3O [M –
H]- 274.0980, found 274.0983.
2-(3-Chlorophenyl)-3-methylpyrazolo[5,1-b]quinazolin-9(4H)-one 4b: Yield 75 %
1
(232 mg). Pale yellow solid, m.p.: 285~287 °C; H NMR (DMSO-d6, 400 MHz): δH
2.34 (s, 3H), 7.25~7.28 (m, 1H), 7.50~7.57 (m, 3H), 7.75~7.84 (m, 3H), 8.20 (d, J =
8.0 Hz, 1H), 11.99 (s, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 8.5, 94.1, 111.9,
116.5, 121.7, 127.0, 127.8, 128.0, 129.0, 131.1, 133.9, 135.2, 135.5, 140.4, 141.2,
153.2, 156.0. IR (KBr):
ν 3290, 3214, 3134, 3074, 3007, 2938, 1667, 1651, 1568,
1492, 1474, 1438, 1406, 1328, 1274, 1222, 1209, 1178, 1082, 948, 785, 749, 693
cm-1. HRMS (ESI, m/z): Calcd for C17H11ClN3O [M – H]+ 308.0591, found 308.0603.
17

ACCEPTED MANUSCRIPT
2-(4-Chlorophenyl)-3-methylpyrazolo[5,1-b]quinazolin-9(4H)-one 4c: Yield 76 %
1
(235 mg). Pale yellow solid, m.p.: 266~268 °C; H NMR (DMSO-d6, 400 MHz): δH
2.32 (s, 3H), 7.25 (t, J = 7.6 Hz, 1H), 7.50 (d, J = 8.4 Hz, 1H), 7.58 (d, J = 8.0 Hz,
2H), 7.74~7.78 (m, 1H), 7.84 (d, J = 8.0 Hz, 2H), 8.19 (d, J = 8.0 Hz, 1H), 11.94 (s,
1H). 13C NMR (DMSO-d6, 100 MHz): δc 8.6, 93.9, 111.9, 116.4, 121.6, 128.0, 129.2,
130.1, 132.3, 133.9, 135.1, 140.4, 141.1, 153.5, 156.0. IR (KBr):
ν 3286, 3215, 3136,
3070, 3029, 3007, 2937, 1666, 1646, 1581, 1567, 1508, 1493, 1473, 1436, 1401,
1327, 1268, 1222, 1207, 1176, 1157, 1091, 1010, 945, 843, 748, 695 cm-1. HRMS
(ESI, m/z): Calcd for C17H11ClN3O [M – H]- 308.0591, found 308.0608.
3-Methyl-2-(p-tolyl)pyrazolo[5,1-b]quinazolin-9(4H)-one 4d: Yield 85 % (246 mg).
1
Pale yellow solid, m.p.: 278~280 °C; H NMR (DMSO-d6, 400 MHz): δH 2.32 (s,
3H), 2.38 (s, 3H), 7.25 (t, J = 7.6 Hz, 1H), 7.33 (d, J = 7.6 Hz, 2H), 7.50 (d, J = 8.4
Hz, 1H), 7.71 (d, J = 8.0 Hz, 2H), 7.74~7.77 (m, 1H), 8.19 (d, J = 8.0 Hz, 1H), 11.87
(s, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 8.7, 21.4, 93.6, 111.9, 116.4, 121.5,
128.0, 128.3, 129.6, 130.6, 135.0, 138.6, 140.4, 141.0, 154.7, 156.0. IR (KBr):
ν
3289, 3241, 3125, 3066, 3029, 1666, 1643, 1581, 1506, 1491, 1470, 1434, 1330,
1306, 1270, 1222, 1206, 1175, 1158, 1112, 1011, 943, 824, 751 cm-1. HRMS (ESI,
m/z): Calcd for C18H14N3O [M – H]- 288.1137, found 288.1149.
2-(4-Fluorophenyl)-3-methylpyrazolo[5,1-b]quinazolin-9(4H)-one 4e: Yield 75 %
1
(220 mg). Pale yellow solid, m.p.: 275~277 °C; H NMR (DMSO-d6, 400 MHz): δH
2.32 (s, 3H), 7.25 (t, J = 7.6 Hz, 1H), 7.34~7.38 (m, 2H), 7.50 (d, J = 8.4 Hz, 1H),
7.74~7.78 (m, 1H), 7.85~7.88 (m, 2H), 8.20 (d, J = 8.0 Hz, 1H), 11.92 (s, 1H). 13C
18

ACCEPTED MANUSCRIPT
NMR (DMSO-d6, 100 MHz): δc 8.6, 93.7, 111.9, 116.1 (d, JF-C = 21.4 Hz), 116.4,
121.6, 128.0, 129.9 (d, JF-C = 3.0 Hz), 130.5 (d, JF-C = 8.4 Hz), 135.1, 140.4, 141.1,
153.8, 156.0, 163.4 (d, JF-C = 127.1 Hz). IR (KBr):
ν 3276, 3208, 3131, 3069, 3007,
2961, 2933, 2856, 1672, 1652, 1607, 1582, 1525, 1508, 1472, 1435, 1330, 1270,
1232, 1209, 1155, 1125, 980, 945, 837, 745 cm-1. HRMS (ESI, m/z): Calcd for
C17H11FN3O [M – H]+ 292.0886, found 292.0894.
2-(4-Methoxyphenyl)-3-methylpyrazolo[5,1-b]quinazolin-9(4H)-one 4f: Yield 86 %
1
(262 mg). Pale yellow solid, m.p.: 280~282 °C; H NMR (DMSO-d6, 400 MHz): δH
2.32 (s, 3H), 3.83 (s, 3H), 7.08 (d, J = 8.4 Hz, 2H), 7.23~7.26 (m, 1H), 7.50 (d, J =
13
8.4 Hz, 1H), 7.73~7.78 (m, 3H), 8.19 (d, J = 8.0 Hz, 1H), 11.85 (s, 1H). C NMR
(DMSO-d6, 100 MHz): δc 8.7, 55.6, 93.4, 112.0, 114.5, 116.4, 121.5, 125.8, 128.0,
129.7, 134.9, 140.4, 140.9, 154.6, 156.0, 160.1. IR (KBr):
ν 3280, 3217, 3141, 3075,
3009, 2938, 2870, 1666, 1612, 1582, 1531, 1510, 1493, 1474, 1437, 1347, 1333,
1303, 1291, 1250, 1222, 1174, 1112, 1019, 1006, 982, 838, 751 cm-1. HRMS (ESI,
m/z): Calcd for C18H14N3O2 [M – H]- 304.1086, found 304.1094.
2-(p-Tolyl)pyrazolo[5,1-b]quinazolin-9(4H)-one 4g: Yield 79 % (217 mg). Pale
1
yellow solid, m.p.: > 300 °C; H NMR (DMSO-d6, 400 MHz): δH 2.37 (s, 3H), 6.55
(s, 1H), 7.26~7.32 (m, 3H), 7.43 (d, J = 8.4 Hz, 1H), 7.77 (t, J = 7.6 Hz, 1H), 7.93 (d,
J = 7.6 Hz, 2H), 8.21 (d, J = 8.0 Hz, 1H), 12.37 (s, 1H). 13C NMR (DMSO-d6, 100
MHz): δc 21.4, 84.5, 112.1, 116.4, 121.8, 126.8, 128.0, 129.8, 129.9, 135.1, 139.2,
140.2, 143.7, 155.4, 156.0. IR (KBr):
ν 3280, 3222, 3138, 3088, 3060, 3025, 2926,
2921, 1678, 1636, 1561, 1501, 1487, 1454, 1423, 1344, 1325, 1246, 1180, 1001, 940,
19

ACCEPTED MANUSCRIPT
870, 826, 759 cm-1. HRMS (ESI, m/z): Calcd for C17H12N3O [M – H]- 274.0980,
found 274.0992.
3-Ethyl-2-phenylpyrazolo[5,1-b]quinazolin-9(4H)-one 4h: Yield 80 % (231 mg). Pale
yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 1.17 (t, J = 7.2 Hz,
3H), 2.80 (q, J = 7.2 Hz, 2H), 7.24~7.28 (m, 1H), 7.46~7.49 (m, 1H), 7.52~7.55 (m,
3H), 7.75~7.78 (m, 3H), 8.21 (d, J = 8.0 Hz, 1H), 11.87 (s, 1H). 13C NMR (DMSO-d6,
100 MHz): δc 15.3, 15.7, 100.7, 112.0, 116.5, 121.7, 128.0, 128.4, 129.1, 133.6, 135.1,
140.4, 140.6, 154.5, 156.1. IR (KBr):
ν 3283, 3232, 3131, 3057, 3007, 2961, 2927,
2870, 1661, 1641, 1578, 1506, 1490, 1475, 1444, 1357, 1263, 1217, 1203, 1172,
1151, 1113, 1078, 1053, 1025, 943, 750, 718, 694 cm-1. HRMS (ESI, m/z): Calcd for
C18H14N3O [M – H]- 288.1137, found 288.1137.
3-Ethyl-7-methyl-2-phenylpyrazolo[5,1-b]quinazolin-9(4H)-one 4i: Yield 76 % (230
mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 1.16 (t, J
= 7.2 Hz, 3H), 2.41 (s, 3H), 2.80 (q, J = 7.2 Hz, 2H), 7.45~7.49 (m, 2H), 7.52~7.55
(m, 2H), 7.60 (d, J = 8.4 Hz, 1H), 7.77 (d, J = 7.2 Hz, 2H), 8.00 (s, 1H), 11.80 (s, 1H).
13C NMR (DMSO-d6, 100 MHz): δc 15.3, 15.7, 20.8, 100.4, 111.8, 116.5, 121.0,
128.3, 129.1, 130.9, 133.7, 136.5, 138.5, 140.7, 154.4, 156.0. IR (KBr):
ν 3281, 3228,
3096, 3055, 3021, 2958, 2925, 2871, 1662, 1643, 1574, 1514, 1475, 1450, 1355,
1335, 1265, 1217, 1174, 1130, 1079, 1054, 1028, 952, 838, 773, 718, 700 cm-1.
HRMS (ESI, m/z): Calcd for C19H16N3O [M – H]- 302.1293, found 302.1292.
7-Bromo-2-phenyl-3-propylpyrazolo[5,1-b]quinazolin-9(4H)-one 4j: Yield 76 % (290
mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 1.16 (t, J
20

ACCEPTED MANUSCRIPT
= 7.2 Hz, 3H), 1.97 (s, 2H), 2.78~2.83 (m, 2H), 7.49~7.56 (m, 4H), 7.77 (d, J = 7.6
Hz, 2H), 7.90 (d, J = 8.8 Hz, 1H), 8.26 (s, 1H), 12.06 (s, 1H). 13C NMR (DMSO-d6,
100 MHz): δc 15.3, 15.7, 21.9, 101.2, 112.9, 113.7, 119.1, 128.4, 129.2, 129.3, 129.8,
133.4, 137.6, 139.5, 140.4, 154.9, 155.0. IR (KBr):
ν 3276, 3225, 3098, 3062, 3012,
2961, 2933, 2874, 1666, 1641, 1574, 1498, 1470, 1447, 1403, 1350, 1336, 1254,
1214, 1184, 1140, 1080, 1053, 1026, 952, 839, 769, 702 cm-1. HRMS (ESI, m/z):
Calcd for C19H15N3OBr [M – H]- 380.0398, found 380.0395.
2-(4-Chlorophenyl)-3-propylpyrazolo[5,1-b]quinazolin-9(4H)-one 4k: Yield 81 %
(273 mg). Pale yellow solid, m.p.: > 300 °C; 1H NMR (DMSO-d6, 400 MHz): δH 0.90
(t, J = 7.2 Hz, 3H), 1.47~1.57 (m, 2H), 2.74~2.78 (m, 2H), 7.25~7.29 (m, 1H), 7.54
(d, J = 8.4 Hz, 1H), 7.57~7.60 (m, 2H), 7.75~7.80 (m, 3H), 8.19~8.22 (m, 1H), 11.84
(s, 1H). 13C NMR (DMSO-d6, 100 MHz): δc 14.1, 23.4, 24.2, 99.2, 112.0, 116.5, 121.7
128.0, 129.2, 130.2, 132.6, 133.9, 135.1, 140.5, 141.1, 153.5, 156.0. IR (KBr):
ν
3366, 3092, 3071, 3008, 2966, 2932, 2838, 1671, 1589, 1529, 1456, 1432, 1372,
1345, 1316, 1300, 1273, 1255, 1205, 1159, 1095, 1059, 1000, 929, 836, 778, 724
cm-1. HRMS (ESI, m/z): Calcd for C19H15ClN3O [M – H]- 336.0904, found 336.0903.
Acknowledgements
We are grateful to the National Natural Science foundation of China (20802061,
21104064), a project funded by the Priority Academic Program Development of
Jiangsu Higher Education Institutions, Qing Lan Project (10QLD008,
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GSFM2011003) and College Industrialization Project (JHB2012-31) of Jiangsu
Province for financial support.
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