Piperidine-Promoted Three-Component Condensation: Synthesis of Chromene Heterocycles and Pyrazolotriazoles

Article abstract of DOI:10.1002/jccs.201700074

Chromenes, the oxygen-containing heterocyclic compounds, have a “special” place in biologically active natural products and in synthetic chemistry and in the fields of medicinal, agrochemical, cosmetic, and pigment industries. In this work, piperidine was used as a base catalyst for the convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo[g]chromene, and pyrazolo[1,2-a] [1,2,4]triazole derivatives at ambient temperature. This methodology has several advantages including the use of easily accessible and inexpensive catalysts, short reaction times, high yields, convenient work-up, and not needing column chromatography.

Full text of DOI:10.1002/jccs.201700074

JOURNAL OF THE CHINESE
CHEMICAL SOCIETY
Article
Piperidine-Promoted Three-Component Condensation: Synthesis of Chromene
Heterocycles and Pyrazolotriazoles
*
*
Mehrnoush Kangani, Nourallah Hazeri, Afshin Yazdani-Elah-Abadi and
Malek-Taher Maghsoodlou
Department of Chemistry, Faculty of Science, University of Sistan and Baluchestan, P.O. Box 98135-674,
Zahedan, Iran
(Received: March 3, 2017; Accepted: July 15, 2017; DOI: 10.1002/jccs.201700074)
Chromenes, the oxygen-containing heterocyclic compounds, have a “special” place in biologically
active natural products and in synthetic chemistry and in the fields of medicinal, agrochemical,
cosmetic, and pigment industries. In this work, piperidine was used as a base catalyst for the con-
venient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo[g]chromene, and
pyrazolo[1,2-a] [1,2,4]triazole derivatives at ambient temperature. This methodology has several
advantages including the use of easily accessible and inexpensive catalysts, short reaction times,
high yields, convenient work-up, and not needing column chromatography.
Keywords: Piperidine; 1,4-dihydropyrano[2,3-c]pyrazole; 5,10-dihydro-4H- benzo[g]chromene;
pyrazolo[1,2-a] [1,2,4]triazole-1,3-dione, ambient temperature
INTRODUCTION
Multi-component reactions (MCRs) have gained
umoxide,11 TEAA (triethylammonium acetate),12 imida-
zole,13 L-proline,14 KF-alumina,14 trichloroaceticacid,15
ceric sulfate,15 SB-DABCO,16 Et3N,17 and TEBA.18
However, some of these methods have drawbacks, such
as long reaction times, unsatisfactory yields, high cata-
lyst loading, or the use of expensive catalysts. Therefore,
it is necessary to further develop a simple synthesis
method of these chromene heterocycles without these
problems.
Pyrazolourazoles and their fused derivatives with
diverse structures have attracted much interest because
of their wide range of biological properties such as anal-
gesic, antibacterial, anti-inflammatory, antidiabetic, and
psychoanaleptic activities19–24 (Figure 1). Many meth-
ods have been reported for their synthesis in recent
years,25–34 and development of new approaches for their
synthesis seems to be an interesting challenge. Piperidine
has been used as an organocatalyst in different organic
syntheses.35–37 In continuation of our research on
MCRs,38–46 we report here an efficient synthesis of 1,4-
dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo
[g]chromene, and pyrazolo[1,2-a] [1,2,4]triazole deriva-
tives in the presence of piperidine as an efficient catalyst
in EtOH at ambient temperature (Scheme 1).
much attention as a broad synthetic strategy for the prep-
aration of drugs and industrial compounds.1 MCRs pro-
vide environmentally friendly processes via reducing
waste production, energy consumption, and the number
of steps.2 Oxygen heterocycles occupy a distinct position
among heterocyclic compounds because of their wide nat-
ural abundance and broad biological and pharmaceutical
significance. In the particular classes of O-heterocycles,
the “chromene” heterocyclic scaffolds represent a “privi-
leged” structural motif well-distributed in natural pro-
ducts with a broad spectrum of potent biological
activities that include antimicrobial,3 antiviral,4
antimalarial,5 antitumor,6 and anticancer.7 Chromene
heterocycles also find uses in the cosmetic and pigment
industries,8 and also as biodegradable agrochemicals.9
Recently, a series of synthetic chromene derivatives have
been prepared and evaluated for their potential antican-
cer, antibacterial, antifungal, and anti-rheumatic proper-
ties and many more (Figure 1). Some catalysts have been
reported to facilitate the synthesis of dihydropyrano-
[2,3-c]pyrazole derivatives and 5,10-dihydro-4H-benzo[g]
chromenes, including γ-alumina,10 nanosized magnesi-
*Corresponding author. Email: mehrnooshkangani@gmail.com; nhazeri@chem.usb.ac.ir
J. Chin. Chem. Soc. 2017
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Article
Kangani et al.
Table 1. Different catalytic systems evaluated for the
synthesis of 1,4-dihydropyrano[2,3-c]pyrazole at
ambient condition
Catalyst
(mol%)
Isolated
yield (%)
Entry
Solvent
Time
48 h
24 h
24 h
Fig. 1. Synthetically important drug-like chromenea
1
2
3
4
5
6
7
—
EtOH (2 mL)
—
Trace
—
and pyrazolourazoles heterocycles.
Piperazine (15) EtOH (2 mL)
Pyridine (15) EtOH (2 mL)
Piperidine (15) EtOH (2 mL) 5 min
Piperidine (20) EtOH (2 mL) 5 min
Piperidine (10) EtOH (2 mL) 20 min
R
90
90
75
70
N
N
O
3
CN
R2
N
6a-6p
7a-7h
8a-8j
N
R2
R2= Ph, H
O
O
NH2
Piperidine (5)
EtOH (2 mL) 30 min
R
O
CH
O
OH
CN
NH2
and pyridine were used as the catalyst under reaction
conditions, and the results are summarized in Table 1.
With these optimized conditions, we tested a vari-
ety aromatic aldehydes including electron-withdrawing
and electron-donating groups. In all cases, the products
were obtained in good to high yields (Table 2). Aliphatic
aldehydes such as heptanal and pentanal were also
tested under the reaction conditions, but even after 48 h
no product was formed (Table 2, Entries 17, 18, 27, 38) .
In order to assess the efficiency and generality of
this methodology, the obtained results from the reaction
of aromaticaldehyde and malononitrile with substrates
3, 4, and 5 by this method were compared with those of
the previously reported methods (Table 3). It was found
that the present method is convincingly superior to the
reported methods with respect to reaction time, yield of
the product, and the amount of catalyst. If possible, syn-
thetic methods should be conducted at ambient tempera-
ture and pressure to reduce the energy consumption.49
This methodology has been carried out at ambient con-
ditions for good economic and environmental impacts.
The proposed mechanism for the preparation
of 1,4-dihydropyrano[2,3-c]pyrazoles is described in
CN
Piperidine, EtOH
room temprature
4
O
+
CN
O
R1
O
O
1
2
R
NH
NH
N
O
O
5
N
N
N
CN
O
NH2
Scheme 1. Synthesis of 1,4-dihydropyrano[2,3-c]pyra-
zole, 5,10-dihydro-4H-benzo[g]chromene,
and pyrazolo[1,2-a] [1,2,4]triazole deriva-
tives in the presence of piperidine as cata-
lyst in EtOH at ambient temperature.
RESULTS AND DISCUSSION
The reaction between 4-methoxybenzaldehyde,
malononitrile, and 3-methyl-1-phenyl-1H-pyrazol-5
(4H)-one was chosen as a model reaction. The reaction
was performed in the presence of different amounts of
the catalyst and solvent (Scheme 2) (Table 1), and it
was found that 15 mol% of piperidine gave the best
result in EtOH (2 mL). In this experiment, no other
organic solvent was tested because of the green chemis-
try concept. Optimization was repeated for the synthesis
of 5,10-dihydro-4H-benzo[g]chromene and pyrazolo
[1,2-a] [1,2,4]triazole, and in all cases 15 mol% of piper-
idine in EtOH (2 mL) gave the best results. Piperazine
Scheme 3. Proposed mechanism for the synthesis of
1,4-dihydropyrano[2,3-c]pyrazoles in the
presence of piperidine as base catalyst.
Scheme 2. Model reaction for optimizing the amount
of catalyst and solvent for the synthesis of
1,4-dihydropyrano[2,3-c]pyrazoles.
2
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Synthesis of Chromenes and Pyrazolotriazoles
Table 2. Synthesis of 1,4-dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo[g]chromene and pyrazolo[1,2-a] [1,2,4]triazole
derivatives in the presence of piperidine as catalyst in EtOH at ambient temperature
Entry
1
Aldehyde
Substrate
3
Product
Time (min)
60
Isolated yield (%)
75
Ob. mp (ºC)
Lit. mp (ºC)
16910
6a
166–168
O
R2
H
CH
2
3
6b
30
90
176–178
17410
O
R2
H
CH
OMe
O
3
4
3
3
6c
6d
40
20
75
80
143–145
178–179
143–14510
R2
H
H
CH
Cl
17511
O
R2
CH
Cl
O
5
3
6e
10
90
202–203
19511
R2 = H
CH
NO2
O
6
7
3
6f
10
10
90
80
188–190
19110
R2
H
CH
NO2
3
6g
175
17711
O
R2 = H
CH
Br
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Article
Kangani et al.
Table 2. Continued
Entry
8
Aldehyde
Substrate
3
Product
Time (min)
20
Isolated yield (%)
75
Ob. mp (ºC)
Lit. mp (ºC)
6h
222–224
223–22612
O
R2
H
CH
OH
O
9
3
6i
6j
20
5
80
90
165–167
213–214
168–17040
210–21240
R2 Ph
CH
10
3
O
R2 Ph
CH
OMe
O
11
3
6k
5
90
170–172
169–17140
R2 Ph
CH
NO2
O
12
13
3
6l
5
90
85
198–200
200–202
195–19740
R2 = Ph
CH
NO2
3
6m
10
190–19240
O
R2 Ph
CH
Cl
O
14
3
6n
5
80
181–183
181–18340
R2 Ph
CH
Cl
Cl
4
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Synthesis of Chromenes and Pyrazolotriazoles
Table 2. Continued
Entry
15
Aldehyde
Substrate
Product
Time (min)
5
Isolated yield (%)
90
Ob. mp (ºC)
Lit. mp (ºC)
3
6o
196–198
198–20040
O
R2 Ph
CH
16
3
6p
10
86
216–218
217–21916
O
R2 Ph
CH
NC
17
18
n-Heptanal
3
—
—
—
—
—
—
—
—
—
—
R2 = H
3
n-Pentanal
R2 Ph
19
4
7a
20
80
259–261
260–26217
O
CH
20
4
7b
15
85
242–244
242–24417
O
CH
OMe
O
21
22
4
4
7c
7d
30
15
75
80
240–242
242–244
236–23918
242–24418
CH
Cl
O
CH
OMe
O
23
4
7e
15
80
253–255
254–25618
CH
OH
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Article
Kangani et al.
Table 2. Continued
Entry
24
Aldehyde
Substrate
4
Product
Time (min)
18
Isolated yield (%)
85
Ob. mp (ºC)
Lit. mp (ºC)
7f
245–246
242–24448
O
CH
NO2
25
26
4
4
7g
7h
10
15
90
85
284
286–28848
O
CH
Cl
Cl
O
245–246
246–24948
CH
OMe
OMe
27
28
n-Pentanal
4
5
—
—
—
—
—
8a
30
70
>300
>30032
O
CH
29
30
31
5
5
5
8b
8c
8d
15
30
20
80
70
85
>300
>300
>300
>30032
>30032
>30032
O
CH
NO2
O
CH
Cl
O
CH
Br
6
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Synthesis of Chromenes and Pyrazolotriazoles
Table 2. Continued
Entry
32
Aldehyde
Substrate
5
Product
Time (min)
20
Isolated yield (%)
70
Ob. mp (ºC)
Lit. mp (ºC)
>30032
8e
>300
O
CH
NO2
O
33
34
35
5
5
5
8f
8g
8h
30
30
30
85
70
80
>300
>300
>300
>30032
>30032
>30032
CH
Cl
O
CH
F
O
CH
OMe
O
36
37
5
5
8i
8j
30
15
80
90
>300
>300
232–23447
CH
OMe
>30032
O
CH
CN
38
n-Heptanal
5
—
48
—
—
—
Scheme 2. First, Knoevenogel condensation between
aromatic aldehyde and malononitrile took place, then
the 2-benzylidenemalononitrile (3) was attacked by the
(5), which led to the intermediate (6). Tautomerization
and cyclization (6) gave the intermediate (7). The subse-
quent tautomerization gave the desired product (8).
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Article
Kangani et al.
References
Table 3. Comparison of the efficiency of piperidine with other reported catalysts in the literature
Entry
Product
Catalyst/condition
Time
Yield (%)
50
51
10
1
2
3
4
5
6
7
8
6b
6b
6b
6b
6j
6j
6j
6j
7b
7b
7c
7c
7c
8f
8f
8f
8f
Boiling water
Cinchona derivatives/CH2Cl2, r.t
γ-alumina/H2O, reflux
Piperidine/EtOH,r.t
TEAA/r.t
Ce(SO4)2.4H2O/100ꢀC
Electrolysis, 0.62 F mol/ NaBr, EtOH, r.t.
Piperidine/EtOH,r.t
Et3N/ CH3CN, r.t
Piperidine/EtOH,r.t
TEBA/solvent-free, 85ꢀC
DBU/H2O, reflux
5 h
20 h
80
96
79
90
92
80
85
90
86
85
90
87
75
95
91
88
85
60 min
30 min
45 min
10 min
20 min
5 min
24 h
Present work
12
15
40
Present work
17
9
10
11
12
13
14
15
16
17
15 min
3.5 h
Present work
18
52
90 min
30 min
35 min
30 min
25
Piperidine/EtOH,r.t
Present work
32
DABCO/ultrasound irradiation, EtOH, 50ꢀC
Et3N, ultrasound irradiation, EtOH, 50ꢀC
Nano Zno/solvent-free, 100ꢀC
Piperidine/EtOH,r.t
53
47
30
Present work
EXPERIMENTAL
Chemicals and apparatus
product was filtered for separation of the product and
washed with EtOH (3 × 2 mL) to give the pure
product.
Melting points were measured on an Electrother-
mal 9100 apparatus. IR spectra were obtained on a
JASCO FT/IR-460 plus spectrometer. 1H and 13C
NMR spectra were recorded on Bruker DRX-400 and
DRX-300 Advance instruments with DMSO as solvent
and TMS as internal reference at 300, 400, and
75 MHz, respectively. Chemicals were purchased from
Merck (Darmastadt,Germany) and Fluka (Buchs,
Switzerland), and used without further purification.
General procedure for the synthesis of 5,10-dihydro-4H-
benzo[g]chromene derivatives
Piperidine (15 mol%) (0.0127 g) was added to a
magnetically stirred solution of aromatic aldehydes
(1.0 mmol), malononitrile (1.0 mmol), and 2-hydroxy-
1,4-naphtoquinone (1.0 mmol) in EtOH (2 mL) at
ambient temperature. The progress of the reaction was
monitored by TLC. After completion of the reaction,
the crude solid product was filtered for separation of
the product and washed with EtOH (3 × 2 mL) to give
the pure product.
General procedure for the synthesis of 3-methyl-1H-
pyrazol-5(4H)-one
In an ice bath, hydrazine monohydrate (1 mmol)
was added to ethylacetoacetate (1 mmol) and stirred
until 3-methyl-1H-pyrazol-5(4H)-one precipitated and
its formation was complete (5 min).
General procedure for the synthesis of pyrazolo[1,2-a]
[1,2,4]triazole derivatives
General procedure for the synthesis of 3-methyl-1,4-
dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives
To a magnetically stirred solution of aromatic
aldehydes (1 mmol), malononitrile (1 mmol) and 3-
methyl-1H-pyrazol-5(4H)-one (1 mmol) or 3-methyl-1
(phenyl)-pyrazol-5(4H)-one (1 mmol) in EtOH (2 mL),
piperidine (0.01 g) was added at ambient temperature.
The progress of the reaction was monitored by TLC.
After completion of the reaction, the crude solid
To a magnetically stirred solution of aromatic
aldehydes (1 mmol), malononitrile (1 mmol), and 4-
phenylurazole (1 mmol) in EtOH (2 mL), piperidine
(0.01 g) was added at ambient temperature. The prog-
ress of the reaction was monitored by TLC. After com-
pletion of the reaction, the crude solid product was
filtered for the separation of product and washed with
EtOH (3 × 2 mL) to give the pure product.
8
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Synthesis of Chromenes and Pyrazolotriazoles
Characterization data of selected compound
(Appendix S1)
OCH3), 4.64 (s, 1H, CH), 6.92 (d, J = 8 Hz, 2H,Ar),
7.19 (br, 2H, NH2), 7.20 (d, J = 8 Hz, 2H, Ar),7.33 (t,
J = 8 Hz,1H, Ar), 7.50 (t, J = 8 Hz, 2H, Ar), 7.80 (d,
J = 8 Hz, 2H, Ar) ppm.
6-Amino-1,4-dihydro-3-methyl-4-(naphthalen-2-yl)-
1-phenylpyrano[2,3-c]pyrazole-5-carbonitrile (6o): IR
(KBr, cm−1): 3390, 3200, 2180, 1655; 1H NMR
(400 MHz, (DMSO-d6) δ 1.77 (s, 3H, CH3), 4.88 (s,
1H, CH), 7.29 (br, 2H, NH2), 7.33–7.96 (m,12H,
Ar) ppm.
2-Amino-5,10-dihydro-4-(2-chlorophenyl)-5,10-diox-
o-4H-benzo[g]chromene-3-carbonitrile (7c): IR (KBr,
cm−1):3365, 3220, 2215, 1652; 1H NMR (300 MHz,
(DMSO-d6) δ (ppm) 5.16 (s, 1H,CH), 7.29 (t, J = 8 Hz,
2H,Ar), 7.39 (br, 2H, NH2), 7.41–8.10 (m,6H, Ar) ppm.
2-Amino-5,10-dihydro-4-(3-methoxyphenyl)-5,10-di-
oxo-4H-benzo[g]chromene-3-carbonitrile (7d): IR (KBr,
cm−1): 3340, 3215, 2215, 1660; 1H NMR (300 MHz,
DMSO- d6) δ 3.73 (s, 3H, OCH3), 4.59 (s, 1H, CH),
6.80–6.90 (m, 3H, Ar), 7.24 (t, J = 9 Hz, 1H, Ar), 7.35
(br, 2H, NH2), 7.82–8.08 (m, 4H, Ar,) ppm; 13C NMR
(75 MHz, DMSO-d6) δ 55.50, 57.84, 112.47, 114.31,
119.76, 120.36, 122.24, 126.29, 126.54, 130.17, 131.16,
131.50, 134.61, 134.98, 145.58, 149.44, 158.75, 158.79,
159.83, 177.32, 183.05 ppm.
6-Amino-1,4-dihydro-3-methyl-4-(4-methoxyphenyl)
pyrano[2,3-c]pyrazole-5-carbonitrile (6b): IR (KBr,
cm−1): 3455, 3320, 2190, 1654; 1H NMR (300 MHz,
(DMSO-d6) δ 1.79 (s, 3H, CH3), 3.73 (s, 3H, OCH3),
4.55 (s, 1H, CH), 6.85 (br,2H,NH2), 6.88 (d, J = 9 Hz,
2H,Ar), 7.07 (d, J = 9 Hz, 2H, Ar), 12.03 (s, 1H,
NH) ppm.
6-Amino-1,4-dihydro-3-methyl-4-(2-chlorophenyl)py-
rano[2,3-c]pyrazole-5-carbonitrile (6c): IR (KBr, cm−1):
1
3470, 3240, 2180, 1638; H NMR (300 MHz, (DMSO-
d6) δ 1.77 (s, 3H, CH3), 5.08 (s, 1H, CH), 6.99 (br, 2H,
NH2), 7.18–7.43 (m, 4H, Ar), 12.16 (s, 1H, NH) ppm.
6-Amino-1,4-dihydro-3-methyl-4-(4-nitrophenyl)py-
rano[2,3-c]pyrazole-5-carbonitrile (6e): IR (KBr, cm−1):
1
3414, 3316, 2186, 1748, H NMR (400 MHz, (DMSO-
d6) δ 1.82 (s, 3H, CH3), 4.84 (s, 1H, CH), 7.06 (s, 2H,
NH2),7.48 (d, J = 8.4 Hz, 2H, Ar), 8.22 (d,
J = 8.4 Hz, 2H, Ar), 12.22 (s,1H, NH) ppm; 13C
NMR (100 MHz, DMSO-d6) δ 10, 31, 36, 41, 97, 121,
124, 129 (2C), 136, 147, 153, 155, 162 ppm.
6-Amino-1,4-dihydro-3-methyl-4-(2-nitrophenyl)pyr-
ano[2,3-c]pyrazole-5-carbonitrile (6f ): IR (KBr, cm−1):
1
3477, 3228, 2196, 1651. H NMR (400 MHz, (DMSO-
d6) δ 1.78 (s,3H, CH3), 5.11 (s, 1H, CH), 7.04 (s, 2H,
NH2), 7.34 (d, J = 6.8 Hz, 1H, Ar), 7.50 (t, J = 7.4 Hz
1H, Ar), 7.67 (, t, J = 7.2 Hz, 1H, Ar), 7.86 (d,
J = 8.0 Hz, 1H, Ar), 12.22 (s, 1H, NH) ppm; 13C NMR
(100 MHz, DMSO-d6) δ 10, 32, 57, 97, 121, 124,
129, 132, 134, 136, 138, 150, 155, 167 ppm.
2-Amino-5,10-dihydro-4-(4-hydroxyphenyl)-5,10-di-
oxo-4H-benzo[g]chromene-3-carbonitrile (7e): IR (KBr,
cm−1): 3515, 3415, 3130,2215, 1771; 1H NMR
(400 MHz, (DMSO-d6) δ 4.52 (s, 1H, CH), 6.69 (d,
J = 8 Hz, 2H, Ar), 7.10 (d, J = 8 Hz, 2H, Ar), 7.28
(br, 2H, NH2), 7.83–8.07 (m, 4H, Ar) ppm.
6-Amino-1,4-dihydro-3-methyl-4-(4-bromophenyl)py-
rano[2,3-c]pyrazole-5-carbonitrile (6g): IR (KBr, cm−1):
3400, 3150, 2175,1649; H NMR(300 MHz, (DMSO-d6)
2-Amino-3-cyano-4-(2-nitrophenyl)-5,10-dioxo-5,10-
dihydro-4H-benzo[g]chromene (7f ): IR (KBr, cm−1):
3429, 3338, 2207,1666, 1631; 1H NMR (400 MHz,
DMSO-d6) δ 5.40 (s,1H, CH), 7.46–8.07(m,10H, Ar and
NH2) ppm; 13C NMR (100 MHz, DMSO-d6) δ 31.4,
56.2, 105.6, 119.3, 121.6122.4, 124.5, 126.4, 128.0, 130.3,
130.9, 131.4, 134.6, 135.0,149.6, 158.2, 159.3, 177.3,
183.1 (2C = O) ppm.
2-Amino-3-cyano-4-(2,4-dichlorophenyl)-5,10-diox-
o-5,10-dihydro-4H-benzo[g]chromene (7g): IR (KBr,
cm−1): 3428, 3344, 2203,1688, 1593.; 1H NMR
(400 MHz, DMSO-d6) δ 5.65 (s,1H, CH), 7.29–8.06
(m, 9H, Ar and NH2) ppm; 13C NMR (100 MHz,
DMSO-d6) δ33.5, 56.3, 105.6, 119.3, 120.6, 124.2,
126.2, 126.4, 126.5, 129.3, 130.6, 130.8, 131.2,
134.8136.1, 150.2, 159.7, 177.1, 182.8 (2C═O) ppm.
1
δ 1.80 (s, 3H, CH3), 4.63 (s, 1H, CH), 6.96 (br, 2H,
NH2), 7.14 (d, J = 8 Hz, 2H, Ar), 7.52 (d, J = 8 Hz,
2H,Ar), 12.16 (s, 1H, NH) ppm.
6-Amino-1,4-dihydro-3-methyl-4-(4-hydroxyphenyl)
pyrano[2,3-c]pyrazole-5-carbonitrile (6h): IR (KBr,
cm−1): 3766, 3214, 3169, 2190, 1489. 1H NMR
(300 MHz, (DMSO-d6) δ 1.77 (s, 3H, CH3), 4.45 (s,
1H,CH), 6.62–6.98 (m,6 H, Ar, NH2), 9.23 (s, 1H,
OH), 12.02 (s, 1H, NH) ppm.
6-Amino-1,4-dihydro-4-(4-methoxyphenyl)-3-methyl-
1-phenylpyrano[2,3-c]pyrazole-5-carbonitrile (6j): IR
(KBr, cm−1): 3392, 2933, 2197, 1663; 1H NMR
(400 MHz, (DMSO-d6) δ 1.80 (s, 3H, CH3), 3.64 (s, 3H,
J. Chin. Chem. Soc. 2017
© 2017 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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9

Article
Kangani et al.
2-Amino-3-cyano-4-(2,4-dimethoxyphenyl)-5,10-dio-
and pyrazolotriazoles with antibacterial properties. All
products were obtained just with simple filtration, and
there was no need for recrystallization or column
chromatography.
xo-5,10-dihydro-4H-benzo[g]chromene (7h): (KBr, cm-1):
3450, 3337, 2194,1661, 1590 cm−1.; 1H NMR (400 MHz,
DMSO-d6) δ 3.72(s, 3H, OMe), 3.77 (s, 3H, OMe), 4.83
(s, 1H, CH), 6.43–7.11(m, 3H, Ar), 7.17–8.06 (m, 6H, Ar
and NH2) ppm; 13CNMR (100 MHz, DMSO-d6) δ 31.2,
55.6, 56.2, 57.2, 105.6, 119.2, 120.1, 122.4, 124.2, 126.2,
126.5, 130.3, 131.5, 134.5135.0, 149.7, 158.3, 159.7 (2C),
177.5, 183.0 (2C═O) ppm.
ACKNOWLEDGMENT
This work was supported by the Research Council
of the University of Sistan and Baluchestan.
7-Amino-5-(4-bromophenyl)-1,2,3,5-tetrahydro-1,3-
dioxo-2-phenylpyrazolo[1,2-a] [1,2,4]triazole-6-carbonitrile
Supporting information
Additional supporting information is available in
the online version of this article.
1
(8d): IR (KBr, cm−1): 3400, 3250, 2255, 1660; H NMR
(400 MHz, (DMSO-d6) δ 5.60 (s, 1H, CH), 7.45 (d,
J = 8 Hz, 2H, Ar), 7.46–7.50 (m, 5H, Ar), 7.66 (d,
J = 8 Hz, 2H, Ar), 7.89 (br, 2H, NH2) ppm.
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JOURNAL OF THE CHINESE
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