Design, synthesis, and evaluation of the anticonvulsant and antidepressant activities of pyrido[2,3-d]pyrimidine derivatives

Article abstract of DOI:10.1007/s00044-016-1559-1

A series of pyrido[2,3-d]pyrimidine derivatives (4a–4n, 5a–5n, 6, and 7) were designed and synthesized as potential anticonvulsants and antidepressants. Their pharmacological activities were evaluated by maximal electroshock test, forced swimming test, an

Full text of DOI:10.1007/s00044-016-1559-1

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res
DOI 10.1007/s00044-016-1559-1
ORIGINAL RESEARCH
Design, synthesis, and evaluation of the anticonvulsant
and antidepressant activities of pyrido[2,3-d]pyrimidine
derivatives
2
2
1,2
1
2
Hong-Jian Zhang
•
Shi-Ben Wang
•
Xiang Wen
•
Jin-Zi Li
•
Zhe-Shan Quan
Received: 3 May 2015 / Accepted: 14 March 2016
Ó Springer Science+Business Media New York 2016
Abstract A series of pyrido[2,3-d]pyrimidine derivatives
4a–4n, 5a–5n, 6, and 7) were designed and synthesized as
Introduction
(
potential anticonvulsants and antidepressants. Their phar-
macological activities were evaluated by maximal elec-
troshock test, forced swimming test, and tail suspension
test in mice. Pharmacological analyses showed that com-
pounds 4-benzyl-6,8-dimethylpyrido[3,2-e]tetrazolo[1,5-
a]pyrimidin-5(4H)-one (4a) and 4-(3-fluorobenzyl)-6,8-
dimethylpyrido[3,2-e]tetrazolo[1,5-a]pyrimidin-5(4H)-one
Depression and epilepsy are commonly encountered neu-
rological disorders (Strine et al., 2005; Wilusz et al., 2014;
Wouters et al., 2014; Reilly et al., 2014); several reports
concerning a connection between these two disorders have
recently been published in the literature (Kwon and Park,
2014; Lacey et al., 2014; Kanner, 2006; Kanner and
Balabanov, 2002). Many recent epidemiological studies
have found a high prevalence of depression in people with
epilepsy, which indicated that 37–50 % of individuals with
epilepsy suffered from depression (Fig. 1) (Fiest et al.,
2014; Kwon and Park, 2014; Kanner, 2005). Despite the
considerable prevalence of depression and epilepsy, there
are few agents that can cure patients with depression and
epilepsy effectively (Italiano et al., 2014; Jerant et al.,
2014; Remi et al., 2010).
(
4e) exhibited the greatest anticonvulsant activity (PI 12.02
and 12.25, respectively, 30 min after intraperitoneal
injection), and were more efficient than the reference
drug, carbamazepine. In addition, 4-(4-fluorobenzyl)-6,8-
dimethylpyrido[3,2-e]tetrazolo[1,5-a]pyrimidin-5(4H)-one
(4f) and 6-(4-fluorobenzyl)-2,4-dimethylpyrido[3,2-e][1,2,4]
triazolo[4,3-a]pyrimidin-5(6H)-one (5f) possessed potent
antidepressant properties that lead to significant reduction
in the duration of the immobility time than did the control
In our previous work, we synthesized a series of 5-(4-
methoxyphenoxy)-tetrazolo[1,5-a]quinazoline (Wang et al.,
2009) (I). At a dose of 100 mg/kg, compound I showed
modest anticonvulsant and antidepressant activity exhibiting
immobility time of 85.2 ± 13.42 s. In order to develop better
anticonvulsant and antidepressant agents, we designed 4-
benzyl-6,8-dimethylpyrido[3,2-e]tetrazolo[1,5-a]pyrimidin-
(P \ 0.001), which possessed activities similar to those of
fluoxetine. 4f showed obvious antidepressant activity at
doses of 10 mg/kg.
Keywords Synthesis Á Tetrazolo Á Triazole Á
Anticonvulsant Á Antidepressant
5(4H)-one (4a) derivatives, using pyridine rings instead of
the benzene rings in compound I and introducing two methyl
at the pyridine rings to increase liposolubility (Fig. 2).
Triazole is the core structural motif in a variety of dif-
ferent compounds in medicinal chemistry and has been
reported to exhibit a broad range of biological properties,
including antimicrobial (Bayrak et al., 2009; Eswaran
et al., 2009), antinociceptive (Ozkay et al., 2012), anti-
inflammatory (Shaveta et al., 2014), antidepressant (Deng
et al., 2014; Donato et al., 2013; Sahu et al., 2013), and
anticonvulsant (Deng et al., 2011; Guan et al., 2010; Plech
&
&
Jin-Zi Li
yjzli@ybu.edu.cn
Zhe-Shan Quan
zsquan@ybu.edu.cn
1
2
Department of Pediatrics, Yanbian University Hospital,
Yanji 133000, People’s Republic of China
College of Pharmacy, Yanbian University, Yanji 133000,
People’s Republic of China
123

Med Chem Res
maximal electroshock test (MES), neurotoxicity using the
rotarod test, and antidepressant activity using the forced
swimming test (FST). To investigate their antidepressant
activity further, we also studied active compounds using
the tail suspension test (TST).
Results and discussion
Chemistry
The synthetic strategies adopted for the synthesis of the
intermediate and target compounds are depicted in
Schemes 1. All synthesized target compounds were con-
1
13
firmed by H Nuclear magnetic resonance (NMR),
NMR, infrared (IR) spectroscopy, and mass spectrography
MS).
Intermediate 3 was synthesized according to a previ-
C
Fig. 1 Epilepsy and depression: estimates of their occurrence
(
et al., 2013) activities. Besides, triazole is the isostere of
tetrazolo. Therefore, a second compound 6-benzyl-2,4-
dimethylpyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrimidin-5(6H)-
one (5a) was designed and synthesized to test whether a
triazole ring could enhance activity (Fig. 2). Furthermore,
two other compounds 6 and 7 were prepared according to
the isostere principle (Fig. 2). Pharmacological tests on
compounds 4a, 5a, 6, and 7 showed that compound 4a had
anticonvulsant activity (Table 1) and 4a and 5a had
antidepressant activity (Fig. 3).
ously described method (Scheme 1). The starting material,
compound 1, was refluxed with pentane-2,4-dione in a
solution of trifluoroacetic acid to yield compound 2. Then,
a key substrate for the reaction, compound 3, was prepared
using an established procedure (Sun et al., 2008), by the
reaction of compound 2 with hydrazine hydrate in boiling
ethanol.
In Scheme 1, the key intermediate 3 was cycled with
NaNO in an ice bath, and subsequently, reacted with an
2
In view of the observations, we designed and synthesized
two novel series of derivatives, 4-alkyl-6,8-dimethylpyrido
appropriate alkyl halide to afford compounds 4a–4n (Sun
et al., 2011). Reaction of compound 3 with boiling
[
3,2-e]tetrazolo[1,5-a]pyrimidin-5(4H)-one (4a–4n) and
-alkyl-2,4-dimethylpyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrim-
HC(OC H ) gave an intermediate that can be treated
2 5 3
6
with alkyl halide to obtain test derivatives 5a–5n. Com-
pound 6 was prepared by reacting compound 3 with
idin-5(6H)-one (5a–5n). Here, we report their synthesis
and an evaluation of their anticonvulsant activity using the
H CCOOH and diverse alkyl halide. Finally, compound 7
3
Fig. 2 Structures of compound
I and target compounds 4a–4n,
O
N
O
N
R
N
R
N
5
a–5n, 6, and 7
N
N
O
N
N
N N
N
O
N
4
a-4n
5
a-5n
N
N
N N
O
N
O
Compound I
N
N
N
N
N
N
N
N
N
6
7
1
23

Med Chem Res
Table 1 Preliminary anticonvulsant activity and neurotoxicity of compounds 4a–4n, 5a–5n, 6, and 7 administered intraperitoneally (i.p.) to
mice
a
MES (mg/kg)
b
TOX 100 mg/kg
Compound
R
1
00
50
4
4
4
4
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
6
7
I
a
b
c
d
e
f
–CH
–CH
–CH
–CH
–CH
–CH
–CH
–CH
–CH
2
2
2
2
2
2
2
2
2
C
C
C
C
C
C
C
C
C
6
6
6
6
6
6
6
6
6
H
H
H
H
H
H
H
H
H
5
4
4
4
4
4
4
4
4
3/3
0/3
0/3
3/3
3/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
3/3
1/3
0/3
3/3
1/3
0/3
3/3
1/3
0/3
0/3
1/3
0/3
0/3
2/3
2/3
c
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
3/3
0/3
3/3
0/3
0/3
0/3
0/3
0/3
(p-CH
3
)
—
(p-OCH
(o-F)
3
)
–
0/3
2/3
–
(m-F)
(p-F)
g
h
i
(o-Cl)
(m-Cl)
(p-Cl)
–
–
–
j
–C
5
–C
6
–C
7
–C
8
H
H
H
H
11
13
15
17
–
k
l
–
–
m
n
a
b
c
d
e
f
–
–C10
H
21
–
–CH
–CH
–CH
–CH
–CH
–CH
–CH
–CH
–CH
2
C
6
C
6
C
6
C
6
C
6
C
6
C
6
C
6
C
6
H
5
H
4
H
4
H
4
H
4
H
4
H
4
H
4
H
4
–
2
2
2
2
2
2
2
2
(p-CH
3
)
–
(p-OCH
(o-F)
3
)
–
0/3
–
(m-F)
(p-F)
–
g
h
i
(o-Cl)
(m-Cl)
(p-Cl)
0/3
–
–
j
–C
5
–C
6
–C
7
–C
8
H
H
H
H
11
13
15
17
0/3
–
k
l
–
m
n
–
–C10
H
21
–
–
–
0/3
a
Maximal electroshock seizure test (number of animals protected/number of animals tested)
Rotarod toxicity test (number of animals exhibiting toxicity/number of animals tested)
Not tested
b
c
was synthesized using cyclization and an alkylation
4n, 5a–5n, 6, and 7 are summarized in Table 1. From
the MES test, we could see that 4a, 4d, 4e, 5d, 5g, and
reaction of compound 3.
5j displayed noticeable anticonvulsant activity at a dose
Anticonvulsant activity
of 100 mg/kg. Whereas, compounds 5e, 5h, 5k, and 5n,
showed partial protection (2/3 or 1/3, 0.5 h) at this dose.
4a and 4e possessed modest anticonvulsant activity at a
dose of 50 mg/kg, which was more efficient than the lead
compound (I). Except 5j and 5l, none of these
compounds displayed neurotoxicity at a dose of 100 mg/
kg.
During the preliminary screening process, compounds
were administered as intraperitoneal (i.p.) injections at
doses of 100 and 50 mg/kg. Their anticonvulsant effects
were assessed at 0.5 h intervals following administration
in mice. The results of the preliminary screening of 4a–
123

Med Chem Res
Fig. 3 Effects of treatment of mice with 4a–4n, 5a–5n, 6, 7, I, and
FXT (50 mg/kg) given intraperitoneally (i.p.) on the immobility time
in the forced swim test (FST). Control group was treated with
dimethyl sulfoxide (DMSO) i.p. Results are represented as
mean ± SEM with n = 8 in each group. Values are significant at
*P \ 0.05; **P \ 0.01; ***P \ 0.001 as compared to control (all
comparisons were made by ANOVA followed by Dunnett’s test)
Scheme 1 Synthesis of target
compounds 4a–4n, 5a–5n, 6,
and 7, Reagents and conditions:
O
O
R
N
NH
a CH
CCOOH, reflux;
b NH NH O, CH
ÁH
reflux. c a. NaNO , HCl, H
°C; b. RX, NaH, DMF, room
temperature (rt); d a.
HC(OC , reflux; b. RX,
NaH, DMF, rt; e a. H CCOOH,
reflux; b. RX, NaH, DMF, rt;
f a. CH COCH COCH
CH CH OH, reflux; b. RX,
NaH, DMF, rt
3 2 3
COCH COCH ,
O
F
3
N
N
N
N
H N
N
H
1
S
2
2
2
2
3
CH
2
OH,
O,
N
2
2
5
a-5n
0
N
N
N
N
2 5
H )
3
a
d
e
3
6
O
O
3
2
3
,
NH
3
2
NH
b
NH2
N
N
H
N
N
N
H
S
2
3
f
O
N
c
N
O
N
N
N
N
R
N
N
7
N
N N
a-4n
4
On the basis of the considerable anticonvulsant activity
carbamazepine, which suggested that the two compounds
had high safety.
suggested in Table 1, two outstanding derivatives, 4a and
e, were chosen for quantitative evaluation trials, for
4
quantification of their anticonvulsant activity [indicated by
median effective dose (ED )] and neurotoxicity [indicated
Antidepressant activity
5
0
by median toxic dose (TD )] in mice (Table 2). Com-
5
In the primary screening, all synthesized compounds were
screened using the forced swim test (FST) in mice. The
FST was designed by Porsolt et al. This animal model is
0
pounds 4a and 4e exhibited protective index (PI) (12.02
and 12.25, respectively) higher than the PI (6.4) of
1
23

Med Chem Res
one of the most widely used tools for the preclinical
screening of putative antidepressant agents. In this test, we
used dimethyl sulfoxide (DMSO) as the vehicle and flu-
oxetine (FXT) as the reference drug; the antidepressant
activity was assessed by their ability to reduce the duration
of immobility behavior. The antidepressant activities of the
compounds (4a–4n, 5a–5n, 6, and 7) and the reference
drug FXT at a dose of 50 mg/kg (i.p.) are shown in Fig. 3.
The results of the FST revealed that some of the com-
pounds (including 4a, 4b, 4f–4i, 4l, 4m, 5a, 5b, 5d, 5f, and
7 did not show any activity. These events suggest that
introduction of a triazole ring gave the derivatives anti-
convulsant activities and that the tetrazolo ring dramati-
cally improved these activities. Then, we assessed the
SARs of all compounds sequentially for both series. Firstly,
5
h) displayed potent antidepressant activities. Particularly,
the two compounds, 4f and 5f, led to significant reductions
in the duration of immobility time compared to the control
group (P \ 0.001), which possessed activities similar to
FXT. Then, the two outstanding compounds (4f and 5f)
revealed more potent activities than the lead compound (I).
Base on the FST results in Fig. 3, 4f and 5f were eval-
uated using a tail suspension test (TST) to effectively
confirm their antidepressant activities. The results of this
test are shown in Fig. 4. Compounds 4f and 5f showed
significant activity profiles at a dose of 50 mg/kg compared
to the control group.
Fig. 4 Effects of treatment of mice with 4f, 5f, and FXT (50 mg/kg)
given intraperitoneally (i.p.) on the immobility time in the tail
suspension test (TST). Control group was treated with dimethyl
sulfoxide (DMSO) i.p. Results are represented as mean ± SEM with
n = 8 in each group. Values are significant at *P \ 0.05; **P \ 0.01;
*
**P \ 0.001 as compared to control (all comparisons were made by
ANOVA followed by Dunnett’s test)
Having confirmed the antidepressant activities of com-
pounds 4f and 5f, we conducted a dose-dependent study of
the compounds at doses of 10, 25, and 50 mg/kg using the
FST. As shown in Fig. 5, both 4f and 5f exhibited potent
antidepressant activities at doses of 25 and 50 mg/kg and,
especially, 4f led to a significant reduction in immobility
time and showed obvious antidepressant activity at dose of
1
0 mg/kg.
Structure–activity relationships
By evaluating the anticonvulsant and antidepressant
activities of the synthesized compounds, we obtained
structure–activity relationships (SARs).
Fig. 5 Effects of treatment of mice with 4f, 5f, and FXT (50, 25, and
1
0 mg/kg) given intraperitoneally (i.p.) on the immobility time in the
In the anticonvulsant test, 4a, 4d, 4e, 5d, 5e, 5g, 5h, 5j,
forced swim test (FST). Control group was treated with dimethyl
sulfoxide (DMSO) i.p. Results are represented as mean ± SEM with
n = 8 in each group. Values are significant at *P \ 0.05; **P \ 0.01;
5
k, and 5n showed anticonvulsant activity at a dose of
00 mg/kg; 4a and 4e possessed anticonvulsant activity at
a dose of 50 mg/kg (Table 1). However, compounds 6 and
1
*
**P \ 0.001 as compared to control (all comparisons were made by
ANOVA followed by Dunnett’s test)
Table 2 Quantitative anticonvulsant evaluation in Mice administered intraperitoneally (i.p.)
a
ED50 (mg/kg)
b
TD50 (mg/kg)
c
PI
Compound
d
4
a
e
45.6 (40.5–51.0)
53.9 (47.6–60.8)
11.8 (8.5–16.4)
548.6 (507.2–594.5)
660.9 (612.4–711.8)
76.1 (55.8–103.7)
12.0
12.3
6.4
4
Carbamazepine
a
ED50: median effective dose affording anticonvulsant protection in 50 % of animals, the dose is measured in mg/kg
TD50: median toxic dose eliciting minimal neurological toxicity in 50 % of animals, the dose is measured in mg/kg
b
c
d
PI: protective index (TD50/ED50
)
9
5 % confidence intervals given in parentheses
123

Med Chem Res
comparing derivatives 4a–4n with different substituents on
the benzene ring the order of activity was H = m-F [ o-
F [ others, and the length of the alkyl chain on these
derivatives did not have an impact on their anticonvulsant
activities. Secondly, for compounds 5a–5n, halogen atoms
antidepressant. Therefore, further studies are necessary to
obtain better agents and gain insight into the mechanisms
of actions of these analogs.
(
F and Cl) contributed equally and the position of the
Experimental protocols
Chemistry
halogen atom on the phenyl ring influenced the activity; the
activity order is o [ m [ p. From 5j to 5n, as the alkyl
chain length increased, the anticonvulsant activity gradu-
ally decreased with compound 5j being the most active
compound.
Reactions were monitored by thin-layer chromatography
on silica gel plates pre-coated with F254. Developed plates
were examined under an ultraviolet lamp (254 nm). Melt-
ing points were determined in open capillary tubes and
were uncorrected. IR spectra were recorded (in KBr) using
a FTIR-1730 spectrometer (PerkinElmer, Waltham, MA,
Analyzing the antidepressant activities of all the com-
pounds, compounds 4a, 4b, 4f–4i, 4l, 4m, 5a, 5b, 5d, 5f,
and 5h exhibited potent antidepressant activities (Fig. 3).
A TST showed that 4f possessed more potential antide-
pressant activity than 5f (Fig. 4) and 4f showed obvious
antidepressant activity at a dose of 10 mg/kg (Fig. 5). It
was determined that the tetrazolo ring gave more contri-
bution to the antidepressant activity than the triazole ring.
Afterward, we discuss the SARs of 4a–4n and 5a–5n.
Firstly, comparing derivatives 4a–4n with different sub-
stituents on the benzene ring the order of activity was
p-F [ m-F [ o-F, o-Cl [ m-Cl [ p-Cl. Analyzing the
antidepressant activities of the synthesized compounds 4j–
1
13
USA). H NMR and C NMR spectra were recorded using
an AV-300 spectrometer (Bruker Daltonik, Bremen, Ger-
many), and all chemical shifts were given in parts per
million relative to that of tetramethylsilane. Mass spectra
were measured using an HP 1100 LC Spectrometer (Agi-
lent Technologies, Santa Clara, CA, USA). High-resolution
mass spectra were measured on a matrix-assisted laser
desorption/ionization tandem time-of-flight (MALDI–
TOF) mass spectrometer (Bruker Daltonik). Main chemi-
cals were purchased from Sigma-Aldrich (Saint Louis,
MO, USA).
4
n, the following SAR was gained. From compound 4j to
m, as the alkyl chain length increased, immobility times
gradually decreased with compound 4 m (with the n-C H
4
8
17
substituted group) being the most active. The trend
reversed, however, when the alkyl chain had more than
eight carbons. Secondly, compared to the activities of the
benzene ring substituted derivatives 5a–5n, it was found
that the F atom gave more contribution to the antidepres-
sant activity than the –CH ,–OCH , and Cl group. The
Synthesis of 5,7-dimethyl-2-thioxo-2,3-dihydropyrido[2,3-d]
pyrimidin-4(1H)-one (2)
A solution of compound 1 (10.00 g, 70.0 mmol) and pen-
tane-2,4-dione (8.00 g, 80.0 mmol) in trifluoroacetic acid
(100 mL) was heated at reflux for 4 h. Eighty percent of
the solution was removed under reduced pressure and then
poured into cool water. The resulting mixture was filtered
under reduced pressure to yield a yellow powder (14.00 g).
3
3
substituents of alkyl chain had no contribution.
Conclusion
Synthesis of 2-hydrazono-5,7-dimethyl-2,3-
dihydropyrido[2,3-d]pyrimidin-4(1H)-one (3)
A series of pyrido[2,3-d]pyrimidine derivatives (4a–4n,
5
a–5n, 6, and 7) were synthesized, and their anticonvulsant
and antidepressant activities were evaluated. In the MES
test in mice, two of the newly synthesized compounds, 4a
and 4e, showed good anticonvulsant activities, exhibiting
PI 12.02 and 12.25, respectively; this was higher than the
PI (6.4) of carbamazepine. In the FST and TST tests, most
compounds showed modest antidepressant activity. In
particular, 4f and 5f showed potent antidepressant activity
Hydrazine hydrate (15.0 mmol) was added to a stirred
solution of compound 2 (10.0 mmol) in ethanol (30 mL),
and the reaction mixture was refluxed for 1 h. The reaction
mixture was cooled to 0 °C and filtered under reduced
pressure to yield a white powder (1.45 g).
General method for the synthesis of compounds (4a–4n)
(
i.p.), similar to FXT and more efficient than the lead
compound (I).
Compound 3 (0.82 g, 4.0 mmol) was dissolved in 20 mL
of 30 % HCl. A solution of NaNO (0.28 g, 4.0 mmol) in
SAR analyses suggested that tetrazolo and triazole rings
could improve the anti-inflammatory therapeutic efficacy
of these derivatives. However, we have not found a com-
pound with both potent activities: anticonvulsant and
2
5 mL of water was added drop by drop to the mixture in an
ice bath, ensuring that the reaction temperature was below
5 °C. The mixture was then stirred at room temperature for
1
23

Med Chem Res
-
155.33, 158.89, 165.05. IR (KBr, cm ): 1685 (C=O),
1
2
h. After the reaction was complete, the precipitate was
?
1620, 1544 (C=N). MS-EI m/z 325 (M ? H ).
filtered and washed with water to produce an intermediate
as a white solid. Then, the dry white solid (1.08 g,
5
.0 mmol) and NaH (0.24 g, 10.0 mmol) were added to dry
Compound 4e
dimethylformamide (15 mL) and stirred for 0.5 h in an ice
bath. Relevant alkyl halide (5.0 mmol) and KI (0.83 g,
1
Yield: 36.77 %; mp: 130 °C. H NMR (CDCl , 300 MHz):
3
5
.0 mmol) were added to the solution and stirred at room
d 2.74 (s, 3H, CH ), 2.91 (s, 3H, CH ), 5.46 (s, 2H,
3
3
1
3
–CH N), 6.98-7.43 (m, 5H, H-Ar). C NMR (CDCl3,
temperature for 72 h. The mixture was poured into cooled
water (20 mL) and filtered to yield the crude residues.
Target compounds 4a–4n were obtained after the crude
residue was purified by column chromatography over SiO2
2
75 MHz): d 22.39, 24.80, 47.15, 108.45, 115.47, 116.25,
116.55, 125.15, 127.57, 130.28, 136.88, 144.38, 150.51,
-
155.29, 158.99, 165.09. IR (KBr, cm ): 1691 (C=O),
1
?
1612, 1543 (C=N). MS-EI m/z 325 (M ? H ).
(
petroleum ether/ethyl acetate = 2/1, v/v). The yields,
melting points, and spectral data for each compound are
provided below.
Compound 4f
1
Compound 4a
Yield: 36.42 %; mp: 176 °C. H NMR (CDCl , 300 MHz):
3
d 2.73 (s, 3H, CH ), 2.90 (s, 3H, CH ), 5.43 (s, 2H,
3
3
1
Yield: 35.17 %; mp: 180 °C. H NMR (CDCl , 300 MHz):
–CH N), 6.96–7.02 (m, 2H, H-Ar), 7.29 (s, 1H, H-7),
2
3
1
3
d 2.75 (s, 3H, CH ), 2.92 (s, 3H, CH ), 5.49 (s, 2H,
CH N), 7.30 (s, 1H, H-7), 7.33-7.67 (m, 5H, H-Ar).
2
7.62–7.67 (m, 2H, H-Ar). C NMR (CDCl , 75 MHz): d
3
3
3
1
3
–
C
22.38, 24.78, 46.95, 108.52, 115.47, 127.54, 130.54,
NMR (CDCl , 75 MHz): d 22.43, 24.82, 47.75, 108.57,
130.59, 131.58, 144.32, 150.49, 155.21, 158.99, 165.00. IR
3
-
(KBr, cm ): 1685 (C=O), 1618, 1544 (C=N). MS-EI m/z
1
1
1
1
27.51, 128.58, 128.76, 129.54, 134.69, 144.35, 150.63,
-
1
55.20, 159.04, 164.94. IR (KBr, cm ): 1683 (C=O),
?
325 (M ? H ).
?
620, 1546 (C=N). MS-EI m/z 307 (M ? H ).
Compound 4g
Compound 4b
1
Yield: 35.09 %; mp: 195 °C. H NMR (CDCl , 300 MHz):
3
1
Yield: 33.14 %; mp: 185 °C. H NMR (CDCl , 300 MHz):
d 2.32 (s, 3H, PhCH ), 2.74 (s, 3H, CH ), 2.91 (s, 3H,
d 2.78 (s, 3H, CH ), 2.90 (s, 3H, CH ), 5.64 (s, 2H,
3
3
3
1
–CH N), 7.09–7.44 (m, 5H, H-Ar). C NMR (CDCl3,
3
3
3
2
1
3
CH ), 5.46 (s, 2H, –CH N), 7.14–7.57 (m, 5H, H-Ar).
3
C
75 MHz): d 22.39, 24.48, 47.61, 108.34, 127.03, 127.63,
127.87, 129.28, 129.97, 131.75, 133.27, 144.50, 150.72,
2
NMR (CDCl , 75 MHz): d 21.06, 22.41, 24.79, 47.52,
3
-
155.41, 159.00, 164.20. IR (KBr, cm ): 1701 (C=O),
1
1
08.61, 127.47, 129.40, 129.54, 131.76, 138.49, 144.20,
-
50.63, 155.16, 159.03, 164.88. IR (KBr, cm ): 1687
1
?
1624, 1543 (C=N). MS-EI m/z 341 (M ? H ).
1
?
C=O), 1618, 1512 (C=N). MS-EI m/z 321 (M ? H ).
(
Compound 4h
Compound 4c
1
Yield: 36.67 %; mp: 188 °C. H NMR (CDCl , 300 MHz):
3
1
Yield: 33.66 %; mp: 157 °C. H NMR (CDCl , 300 MHz):
d 2.73 (s, 3H, CH ), 2.90 (s, 3H, CH ), 3.76 (s, 3H, OCH ),
d 2.75 (s, 3H, CH ), 2.91 (s, 3H, CH ), 5.44 (s, 2H,
3
3
3
1
–CH N), 7.28–7.60 (m, 5H, H-Ar). C NMR (CDCl3,
3
3
3
3
2
5
.40 (s, 2H, –CH N), 6.82–6.86 (m, 2H, H-Ar), 7.28 (s, 1H,
2
75 MHz): d 22.40, 24.81, 47.10, 108.45, 127.57, 127.72,
128.82, 129.42, 130.04, 134.56, 136.46, 144.36, 150.49,
1
3
H-7), 7.59–7.61 (m, 2H, H-Ar).
C NMR (CDCl3,
-
155.29, 158.98, 165.10. IR (KBr, cm ): 1699 (C=O),
1
7
1
1
5 MHz): d 22.39, 24.78, 47.21, 55.25, 108.63, 113.99,
?
1624, 1543 (C=N). MS-EI m/z 341 (M ? H ).
26.92, 127.46, 131.16, 144.30, 150.56, 155.13, 159.00,
-
1
59.73, 164.83. IR (KBr, cm ): 1688 (C=O), 1618, 1545
?
(
C=N). MS-EI m/z 337 (M ? H ).
Compound 4i
1
Compound 4d
Yield: 36.10 %; mp: 212 °C. H NMR (CDCl , 300 MHz):
3
d 2.75 (s, 3H, CH ), 2.91 (s, 3H, CH ), 5.44 (s, 2H,
3
3
1
13
–CH N), 7.28–7.61 (m, 5H, H-Ar). C NMR (CDCl3,
Yield: 35.26 %; mp: 170 °C. H NMR (CDCl , 300 MHz):
3
2
d 2.75 (s, 3H, CH ), 2.89 (s, 3H, CH ), 5.58 (s, 2H,
75 MHz): d 22.38, 24.80, 47.03, 108.47, 127.55, 128.93,
131.07, 133.10, 134.62, 144.34, 150.49, 155.23, 158.99,
3
3
1
3
CH N), 7.06–7.45 (m, 5H, H-Ar). C NMR (CDCl3,
–
7
1
2
-
165.07. IR (KBr, cm ): 1701 (C=O), 1624, 1543 (C=N).
1
5 MHz): d 22.40, 24.81, 41.84, 108.44, 115.65, 115.93,
24.35, 127.56, 130.23, 130.41, 135.03, 144.43, 150.67,
?
MS-EI m/z 341 (M ? H ).
123

Med Chem Res
-
cm ): 1699 (C=O), 1624, 1543 (C=N). MS-EI m/z 357
1
Compound 4j
?
M ? H ).
(
1
Yield: 30.20 %; mp: 132 °C. H NMR (CDCl , 300 MHz):
3
d 0.92 (t, 3H, J = 6.0 Hz, –CH CH ), 1.22-1.41 (m, 6H,
General method for the synthesis of compounds (5a–5n)
2
3
–
(CH ) –), 2.76 (s, 3H, CH ), 2.92 (s, 3H, CH ), 4.32 (t,
2 3 3 3
1
H, J = 7.5 Hz, –CH N), 7.31 (s, 1H, H-7). C NMR
3
2
A solution of compound 3 (10.00 g, 56.5 mmol) in triethyl
orthoformate (180 mL) refluxed for 2 h. Petroleum ether
(360 mL) was added to the reaction mixture which was
cooled to 0 °C. The mixture was filtered under reduced
pressure to yield a yellow powder (8.20 g). Then, the
alkylation of the intermediate for the synthesis of com-
pounds 5a–5n is similar to that for 4a–4n.
2
(
CDCl , 75 MHz): d 13.91, 22.28, 22.39, 24.79, 27.06,
3
2
8.77, 44.72, 108.54, 127.50, 144.36, 150.48, 155.10,
-
59.13, 164.81. IR (KBr, cm ): 1698 (C=O), 1620, 1543
1
1
?
C=N). MS-EI m/z 287 (M ? H ).
(
Compound 4k
1
Yield: 35.47 %; mp: 127 °C. H NMR (CDCl , 300 MHz):
Compound 5a
3
d 0.89 (t, 3H, J = 6.0 Hz, –CH CH ), 1.24–1.40 (m, 8H,
2
3
1
–
(CH ) –), 2.75 (s, 3H, CH ), 2.91 (s, 3H, CH ), 4.32 (t,
2
Yield: 14.44 %; mp: 200 °C. H NMR (CDCl , 300 MHz):
4
3
3
1
3
3
H, J = 7.5 Hz, –CH N), 7.31 (s, 1H, H-7). C NMR
2
d 2.61 (s, 3H, CH ), 2.86 (s, 3H, CH ), 5.47 (s, 2H,
2
3
3
(
CDCl , 75 MHz): d 13.98, 22.39, 22.49, 24.79, 26.36,
–CH N), 7.12 (s, 1H, H-7), 7.27–7.69 (m, 5H, H-Ar), 9.00
2
3
1
3
2
1
1
7.34, 31.34, 44.75, 108.55, 127.50, 144.36, 150.48,
(s, 1H, –N=CH–). C NMR (CDCl , 75 MHz): d 22.38,
3
-
55.10, 159.12, 164.81. IR (KBr, cm ): 1698 (C=O),
1
24.48, 46.42, 108.38, 126.13, 128.14, 128.56, 129.53,
?
622, 1544 (C=N). MS-EI m/z 301 (M ? H ).
135.31, 135.62, 144.53, 148.09, 154.82, 159.05, 163.50. IR
-
KBr, cm ): 1683 (C=O), 1614, 1571 (C=N). MS-EI m/z
1
(
?
306 (M ? H ).
Compound 4l
1
Yield: 32.41 %; mp: 121 °C. H NMR (CDCl , 300 MHz):
Compound 5b
3
d 0.89 (t, 3H, J = 7.5 Hz, –CH CH ), 1.29–1.40 (m, 10H,
2
3
1
–
(CH ) –), 2.76 (s, 3H, CH ), 2.92 (s, 3H, CH ), 4.33 (t,
2
Yield: 15.25 %; mp: 170 °C. H NMR (CDCl , 300 MHz):
5
3
3
3
1
H, J = 7.5 Hz, –CH N), 7.31 (s, 1H, H-7). C NMR
3
2
d 2.32 (s, 3H, PhCH ), 2.65 (s, 3H, CH ), 2.86 (s, 3H,
2
3
3
(
CDCl , 75 MHz): d 14.05, 22.40, 22.54, 24.81, 26.68,
CH ), 5.43 (s, 2H, –CH N), 6.91 (s, 1H, H-7), 7.14-7.39
3 2
3
1
3
2
1
1
7.41, 28.86, 31.67, 44.76, 108.55, 127.50, 144.37, 150.49,
(m, 4H, H-Ar), 8.51 (s, 1H, –N=CH–). C NMR (CDCl3,
75 MHz): d 21.18, 22.64, 25.37, 50.23, 106.38, 121.60,
128.74, 129.53, 129.85, 131.75, 138.39, 141.84, 146.96,
-
55.10, 159.14, 164.82. IR (KBr, cm ): 1698 (C=O),
1
?
624, 1543 (C=N). MS-EI m/z 315 (M ? H ).
-
1
1
53.18, 161.07, 166.21. IR (KBr, cm ): 1705 (C=O),
?
1593, 1554 (C=N). MS-EI m/z 320 (M ? H ).
Compound 4m
1
Yield: 34.61 %; mp: 115 °C. H NMR (CDCl , 300 MHz):
Compound 5c
3
d 0.88 (t, 3H, J = 6.0 Hz, –CH CH ), 1.23–1.39 (m, 12H,
2
3
1
–
(CH ) –), 2.76 (s, 3H, CH ), 2.92 (s, 3H, CH ), 4.32 (t,
2
Yield: 14.37 %; mp: 170 °C. H NMR (CDCl , 300 MHz):
6
3
3
3
1
H, J = 7.5 Hz, -CH N), 7.31 (s, 1H, H-7). C NMR
3
2
d 2.66 (s, 3H, CH ), 2.91 (s, 3H, CH ), 3.75 (s, 3H, OCH ),
2
3
3
3
(
CDCl , 75 MHz): d 14.06, 22.39, 22.60, 24.79, 26.71,
5.80 (s, 2H, –CH N), 6.80–7.58 (m, 5H, H-Ar), 8.10 (s, 1H,
2
3
1
3
2
7.40, 29.13, 29.15, 31.73, 44.76, 108.55, 127.50, 144.37,
–N=CH–). C NMR (CDCl , 75 MHz): d 22.70, 24.96,
3
-
50.49, 155.10, 159.13, 164.82. IR (KBr, cm ): 1699
1
1
47.57, 55.22, 113.76, 122.37, 128.22, 129.93, 130.63,
?
C=O), 1624, 1543 (C=N). MS-EI m/z 329 (M ? H ).
(
132.27, 139.55, 149.95, 152.97, 154.81, 159.35, 163.60. IR
-
KBr, cm ): 1701 (C = O), 1600, 1555 (C = N). MS-EI
1
(
?
m/z 336 (M ? H ).
Compound 4n
1
Yield: 35.27 %; mp: 100 °C. H NMR (CDCl , 300 MHz):
Compound 5d
3
d 0.87 (t, 3H, J = 6.0 Hz, –CH CH ), 1.22–1.40 (m, 16H,
2
3
1
–
(CH ) –), 2.76 (s, 3H, CH ), 2.91 (s, 3H, CH ), 4.32 (t,
2
Yield: 13.72 %; mp: 220 °C. H NMR (CDCl , 300 MHz):
8
3
3
3
1
H, J = 7.5 Hz, –CH N), 7.31 (s, 1H, H-7). C NMR
3
2
d 2.65 (s, 3H, CH ), 2.81 (s, 3H, CH ), 4.70 (s, 2H,
2
3
3
(
CDCl , 75 MHz): d 14.10, 18.42, 22.38, 22.66, 24.79,
6.71, 27.40, 29.19, 29.25, 29.47, 31.85, 44.76, 108.54,
–CH N), 7.00 (s, 1H, H-7), 7.02–7.50 (m, 4H, H-Ar), 10.66
2
3
1
3
2
(s, 1H, –N=CH–). C NMR (CDCl , 75 MHz): d 22.21,
3
1
27.49, 144.36, 150.48, 155.10, 159.13, 164.81. IR (KBr,
25.10, 28.35, 111.83, 115.38, 115.67, 119.36, 123.02,
1
23

Med Chem Res
1
1
24.41, 129.72, 131.62, 138.80, 152.46, 158.36, 159.53,
25.36, 49.71, 106.48, 121.76, 129.06, 130.10, 131.06,
133.20, 134.56, 146.96, 153.23, 156.61, 160.96, 166.27. IR
-1
-
63.76, 165.01. IR (KBr, cm ): 1676 (C=O), 1575, 1552
1
?
(
C=N). MS-EI m/z 324 (M ? H ).
(KBr, cm ): 1676 (C=O), 1610, 1566 (C=N). MS-EI m/z
?
40 (M ? H ).
3
Compound 5e
Compound 5j
1
Yield: 15.63 %; mp: 185 °C. H NMR (CDCl , 300 MHz):
3
1
d 2.62 (s, 3H, CH ), 2.86 (s, 3H, CH ), 5.44 (s, 2H,
3
3
Yield: 17.03 %; mp: 110 °C. H NMR (CDCl , 300 MHz):
3
–
CH N), 6.93–7.44 (m, 5H, H-Ar), 9.00 (s, 1H, –N=CH–).
2
d 0.89 (t, 3H, J = 6.0 Hz, –CH CH ), 1.22–1.38 (m, 6H,
–(CH ) –), 2.62 (s, 3H, CH ), 2.85 (s, 3H, CH ), 4.30
2 3 3 3
2
3
1
3
C NMR (CDCl , 75 MHz): d 22.35, 24.48, 45.85, 108.24,
3
1
1
15.24, 116.40, 125.08, 126.19, 130.02, 130.13, 135.38,
(
t, 2H, J = 6.0 Hz, –CH N), 6.89 (s, 1H, H-7), 8.54 (s, 1H,
2
1
3
37.87, 144.54, 147.94, 154.89, 159.01, 163.67. IR (KBr,
-
–
2
1
1
N=CH–). C NMR (CDCl , 75 MHz): d 13.90, 22.22,
3
1
cm ): 1678 (C=O), 1614, 1553 (C=N). MS-EI m/z 324
?
M ? H ).
2.62, 25.30, 28.26, 28.59, 47.13, 106.19, 121.42, 129.41,
-
46.92, 153.11, 156.78, 161.04, 166.18. IR (KBr, cm ):
1
(
708 (C=O), 1603, 1543 (C=N). MS-EI m/z 286
?
M ? H ).
Compound 5f
(
1
Yield: 12.99 %; mp: 215 °C. H NMR (CDCl , 300 MHz):
3
Compound 5k
d 2.61 (s, 3H, CH ), 2.86 (s, 3H, CH ), 5.42 (s, 2H,
3
3
–
CH N), 6.96–7.71 (m, 5H, H-Ar), 9.00 (s, 1H, –N=CH–).
2
1
Yield: 16.90 %; mp: 108 °C. H NMR (CDCl , 300 MHz):
1
3
3
C NMR (CDCl , 75 MHz): d 22.35, 24.47, 45.66, 108.34,
3
d 0.87 (t, 3H, J = 6.0 Hz, –CH CH ), 1.22–1.33 (m, 8H,
(CH ) –), 2.62 (s, 3H, CH ), 2.85 (s, 3H, CH ), 4.30
2 4 3 3
2
3
1
1
15.25, 115.54, 126.15, 131.55, 131.66, 135.35, 144.53,
–
-
47.97, 154.83, 159.02, 163.59. IR (KBr, cm ): 1678
1
(
t, 2H, J = 7.5 Hz, –CH N), 6.89 (s, 1H, H-7), 8.54 (s, 1H,
2
?
C=O), 1610, 1566 (C=N). MS-EI m/z 324 (M ? H ).
(
13
N=CH–). C NMR (CDCl , 75 MHz): d 13.96, 22.45,
2.63, 25.28, 26.16, 28.54, 31.31, 47.17, 106.21, 121.42,
–
2
1
3
Compound 5g
29.41, 146.91, 153.15, 156.78, 161.00, 166.16. IR (KBr,
-
cm ): 1710 (C=O), 1595, 1550 (C=N). MS-EI m/z 300
?
M ? H ).
1
1
Yield: 16.54 %; mp: 200 °C. H NMR (CDCl , 300 MHz):
d 2.53 (s, 3H, CH ), 2.88 (s, 3H, CH ), 5.79 (s, 2H,
3
(
3
3
–
CH N), 6.96 (s, 1H, H-7), 7.02–7.43 (m, 4H, H-Ar), 8.88
2
1
3
Compound 5l
(
s, 1H, –N=CH–). C NMR (CDCl , 75 MHz): d 22.55,
3
2
1
1
9.70, 45.62, 104.73, 122.13, 126.78, 127.32, 128.52,
1
Yield: 16.88 %; mp: 108 °C. H NMR (CDCl , 300 MHz):
3
29.65, 133.14, 133.52, 135.15, 148.30, 150.80, 154.88,
-
55.48, 165.44. IR (KBr, cm ): 1678 (C=O), 1589, 1545
1
d 0.88 (t, 3H, J = 6.0 Hz, –CH CH ), 1.30–1.89 (m, 10H,
–(CH ) –), 2.61 (s, 3H, CH ), 2.86 (s, 3H, CH ), 4.67
2 5 3 3
2
3
?
(
C=N). MS-EI m/z 340 (M ? H ).
(
t, 2H, J = 7.5 Hz, –CH N), 6.94 (s, 1H, H-7), 8.83 (s, 1H,
2
1
3
–
2
N=CH–). C NMR (CDCl , 75 MHz): d 14.09, 22.61,
3
Compound 5 h
5.15, 26.65, 27.33, 28.37, 28.89, 31.71, 44.81, 104.62,
1
121.48, 134.77, 148.06, 151.05, 154.75, 155.61, 165.03. IR
Yield: 15.41 %; mp: 181 °C. H NMR (CDCl , 300 MHz):
3
-
KBr, cm ): 1710 (C=O), 1595, 1550 (C=N). MS-EI m/z
1
(
d 2.62 (s, 3H, CH ), 2.86 (s, 3H, CH ), 5.42 (s, 2H,
CH N), 7.14 (s, 1H, H-7), 7.21–7.62 (m, 4H, H-Ar), 9.00
2
3
3
?
14 (M ? H ).
3
–
1
3
(
s, 1H, –N=CH–). C NMR (CDCl , 75 MHz): d 22.35,
3
2
1
1
4.48, 45.80, 108.24, 126.20, 127.69, 128.36, 129.29,
Compound 5m
29.83, 134.35, 135.39, 137.42, 144.53, 147.92, 154.89,
-
58.99, 163.68. IR (KBr, cm ): 1700 (C=O), 1593, 1552
1
1
Yield: 17.51 %; mp: 103 °C. H NMR (CDCl
d 0.88 (t, 3H, J = 6.0 Hz, –CH CH ), 1.25–1.94 (m, 12H,
(CH ) –), 2.62 (s, 3H, CH ), 2.85 (s, 3H, CH ), 4.30
, 300 MHz):
3
?
(
C=N). MS-EI m/z 340 (M ? H ).
2
3
–
2
6
3
3
Compound 5i
(t, 2H, J = 7.5 Hz, –CH
1
2
N), 6.89 (s, 1H, H–7), 8.54 (s, 1H,
3
–
N=CH–). C NMR (CDCl , 75 MHz): d 14.04, 22.62,
3
1
Yield: 15.74 %; mp: 230 °C. H NMR (CDCl , 300 MHz):
d 2.65 (s, 3H, CH ), 2.86 (s, 3H, CH ), 5.44 (s, 2H,
25.29, 26.49, 28.58, 29.09, 29.31, 29.68, 31.69, 47.17,
106.20, 121.41, 129.40, 146.92, 153.12, 156.78, 161.02,
3
3
3
-
1
166.16. IR (KBr, cm ): 1710 (C=O), 1595, 1550 (C=N).
–
CH N), 6.93 (s, 1H, H-7), 7.27–7.44 (m, 4H, H-Ar), 8.53
2
1
3
?
MS-EI m/z 328 (M ? H ).
(
s, 1H, –N=CH–). C NMR (CDCl , 75 MHz): d 22.63,
3
123

Med Chem Res
Compound 5n
evaluate anticonvulsant activities. The neurotoxicity of the
compounds was measured in mice by the rotarod test (Krall
et al., 1978). Antidepressant activities were evaluated using
FST and TST (Porsolt et al., 1977; Duarte et al., 2014). All
compounds were tested for anticonvulsant activities and
antidepressant activities using Kun-Ming mice in the
weight range of 20–24 g purchased from the Laboratory of
Animal Research, College of Pharmacy, Yanbian Univer-
sity, China. The mice were maintained on a 12-h light/dark
cycle in a temperature-controlled (23 ± 2 °C) laboratory.
Food and water were available ad libitum. The tested
compounds were dissolved in DMSO and injected
intraperitoneally in a standard volume of 1 mL/20 g body
weight.
1
Yield: 17.12 %; mp: 100 °C. H NMR (CDCl , 300 MHz):
d 0.88 (t, 3H, J = 6.0 Hz, –CH CH ), 1.26–1.93 (m, 16H,
3
2
3
–
(CH ) –), 2.63 (s, 3H, CH ), 2.87 (s, 3H, CH ), 4.31
2 8 3 3
(
t, 2H, J = 7.5 Hz, –CH N), 6.90 (s, 1H, H-7), 8.55 (s, 1H,
2
1
3
–
2
4
1
1
N=CH–). C NMR (CDCl , 75 MHz): d 14.10, 18.46,
2.66, 25.31, 26.50, 28.59, 29.13, 29.25, 29.46, 31.85,
3
7.19, 58.45, 106.21, 121.44, 129.41, 146.94, 153.12,
-
56.80, 161.04, 166.20. IR (KBr, cm ): 1712 (C=O),
1
?
602, 1556 (C=N). MS-EI m/z 356 (M ? H ).
Synthesis of 6-benzyl-2,9-dimethylpyrido[3,2-
e][1,2,4]triazolo[4,3-a]pyrimidin-5(6H)-one (6)
A solution of compound 3 (1.00 g, 5.6 mmol) in acetic acid
(
Maximal electroshock test
20 mL) refluxed for 10 h. The reaction mixture was cooled
to 0 °C and poured into cool water. The mixture was filtered
under reduced pressure to yield a yellow powder (0.59 g).
Then, the alkylation of the intermediate for the synthesis of
compound 6 is similar to that for 4a–4n.
Seizures were elicited with a 60-Hz alternating current of
50-mA intensity in mice. The current was applied via ear-
clip electrodes for 0.2 s. Protection against the spread of
MES-induced seizures was defined as the absence of tonic
extension of the hind leg. At 30 min after the administra-
tion of the compounds, the activities were evaluated using
the MES test. In preliminary screening, each compound
was administered at doses of 100 and 50 mg/kg for eval-
uating the preliminary anticonvulsant activity. For deter-
1
Yield: 23.38 %; mp: 196 °C. H NMR (CDCl3,
3
3
7
2
1
1
00 MHz): d 2.59 (s, 3H, CH ), 2.86 (s, 3H, CH ), 2.97 (s,
3
3
H, CH ), 5.46 (s, 2H, -CH N), 7.10 (s, 1H, H-7), 7.26-
3
2
1
3
.67 (m, 5H, H-Ar). C NMR (CDCl , 75 MHz): d 15.72,
3
2.67, 24.48, 46.14, 108.78, 125.43, 127.99, 128.48,
28.78, 129.49, 135.84, 147.65, 148.94, 154.55, 159.18,
mination of ED50 and TD , the quantitative evaluation was
50
-
1
62.44. IR (KBr, cm ): 1722 (C = O), 1614, 1571
prepared. Groups of 10 mice were administered arranged
intraperitoneal doses of the tested compound until at least
three points were established in the range of 10–90 %
seizure protection or neurotoxicity. From these data, the
respective ED , TD values, and 95 % confidence inter-
?
(
C = N). MS-EI m/z 320 (M ? H ).
Synthesis of 3-benzyl-2-(3,5-dimethyl-1H-pyrazol-1-yl)-
,7-dimethylpyrido[2,3-d] pyrimidin-4(3H)-one (7)
5
5
0
50
vals were calculated using probit analysis.
A mixture of compound 3 (1.00 g, 5.1 mmol) and pentane-
,4-dione (0.51 g, 5.1 mmol) in dioxane (10 mL) was
2
Rotarod test
refluxed for 5 h, then cooled and poured into cool water.
The mixture was filtered under reduced pressure to yield a
yellow powder. The alkylation of the intermediate for the
synthesis of compound 7 is similar to that for 4a–4n.
The mice were trained to stay on an accelerating rotarod of
1-inch diameter that rotated at 10 rpm. Trained animals
were given i.p. injections of the test compounds. Neuro-
toxicity was indicated by the inability of the animal to
maintain equilibrium on the rod for at least 1 min in each
of the trials.
1
Yield: 23.38 %; mp: 170 °C. H NMR (CDCl3,
3
3
1
00 MHz): d 1.97 (s, 3H, CH ), 2.33 (s, 3H, CH ), 2.64 (s,
3
3
H, CH ), 2.91 (s, 3H, CH ), 5.63 (s, 2H, –CH N), 5.87 (s,
2
3
3
H, H-pyrazole), 7.10 (s, 1H, H-6), 6.87–7.19 (m, 5H,
1
3
H-Ar). C NMR (CDCl , 75 MHz): d 11.45, 13.67, 22.38,
Forced swimming test (FST)
3
2
1
1
4.99, 46.29, 107.49, 112.79, 125.58, 127.48, 127.75,
28.34, 136.53, 143.48, 147.04, 151.47, 152.46, 157.36,
On the test day, male Kunming mice were assigned to
different groups (n = 8 for each group).The synthesized
compounds and the standard drug, fluoxetine, were
administered by i.p. injection. After 30 min, the mice were
dropped one at a time into a Plexiglas cylinder (height,
-
1
63.31, 165.07. IR (KBr, cm ): 1703 (C=O), 1606, 1553
?
(
C=N). MS-EI m/z 360 (M ? H ).
Pharmacology
25 cm; diameter, 10 cm; containing water to a height of
The MES tests were carried out, according to the phase I
tests of the antiepileptic drug development program, to
18 cm at 23–25 °C). A mouse was judged immobile if it
floated in the water in an upright position and made only
1
23

Med Chem Res
slight movements to prevent sinking. The total duration of
immobility was recorded in the last 4 min of a total period
of 6 min. A decrease in the duration of immobility may
indicate antidepressant-like effects.
Fiest KM, Patten SB, Altura KC, Bulloch AG, Maxwell CJ, Wiebe S,
Macrodimitris S, Jette N (2014) Patterns and frequency of the
treatment of depression in persons with epilepsy. Epilepsy Behav
3
9c:59–64
Guan LP, Sui X, Deng XQ, Quan YC, Quan ZS (2010) Synthesis and
anticonvulsant activity of a new 6-alkoxy-[1,2,4]triazolo[4,3-
b]pyridazine. Eur J Med Chem 45:1746–1752
Tail suspension test (TST)
Italiano D, Spina E, de-Leon J (2014) Pharmacokinetic and pharma-
codynamic interactions between antiepileptics and antidepres-
sants. Expert Opin Drug Metab Toxicol 10:1457–1489
Jerant A, Kravitz RL, Fernandez GE, Feldman MD, Cipri C, Nishio
D, Knoepfler A, Wooddell MK, Baquero V, Franks P (2014)
Potential antidepressant overtreatment associated with office use
of brief depression symptom measures. J Am Board Fam Med
27:611–620
Male mice were individually suspended by the tail above
the floor and affixed with adhesive tape placed approxi-
mately 1–2 cm from the tip of the tail. The total duration of
immobility was recorded in the last 6 min of a total period
of 7 min. Mice were determined to be immobile when they
were completely motionless and hung passively.
Kanner AM (2005) Depression in epilepsy: a neurobiologic perspec-
tive. Epilepsy Curr 5:21–27
Kanner AM (2006) Depression and epilepsy: a new perspective on
two closely related disorders. Epilepsy Curr 6:141–146
Kanner AM, Balabanov A (2002) Depression and epilepsy: how
closely related are they? Neurology 58:S27–S39
Krall RJ, Penry JK, White BG, Kupferberg HJ (1978) Antiepileptic
drug development: II Anticovulsant drug screening. Epilepsia
Statistical analyses
Data are represented as the mean ± SEM. Statistical
analyses for comparing control and experimental groups
were done using one-way analysis of variance followed by
the Dunnett’s test using GraphPad Prism 5 (GraphPad, San
Diego, CA, USA). P \ 0.05 was considered significant.
1
9:409–428
Kwon OY, Park SP (2014) Depression and anxiety in people with
epilepsy. J Clin Neurol 10:175–188
Lacey CJ, Salzberg MR, D’Souza WJ (2014) Serotonin transporter
genexenvironment and risk of depression in community-treated
epilepsy. Epilepsy Behav 39c:33–37
Ozkay UD, Can OD, Kaplancikli ZA (2012) Antinociceptive
activities of some triazole and pyrazoline moieties-bearing
compounds. Med Chem Res 21:1056–1061
Acknowledgments This work was supported by the National Nat-
ural Science Foundation of China (Nos. 81160382 and 81360468) and
National Science and Technology Major Project of China (No.
2
012ZX09103-101-044).
Plech T, Luszczki JJ, Wujec M, Flieger J, Pizon M (2013) Synthesis,
characterization and preliminary anticonvulsant evaluation of
some 4-alkyl-1,2,4-triazoles. Eur J Med Chem 60:208–215
Porsolt RD, Bertin A, Jalfre M (1977) Behavioral despair in mice: a
primary screening test for antidepressants. Arch Int Pharmaco-
dyn Ther 229:327–336
Compliance with ethical standards
Conflict of interest We declare that we have no conflict of interest
with respect to this study.
Reilly C, Atkinson P, Das KB, Chin RF, Aylett SE, Burch V, Gillberg
C, Scott RC, Neville BG (2014) Neurobehavioral comorbidities
in children with active epilepsy: a population-based study.
Pediatrics 133:1586–1593
References
Bayrak H, Demirbas A, Demirbas N, Karaoglu SA (2009) Synthesis
of some new 1,2,4-triazoles starting from isonicotinic acid
hydrazide and evaluation of their antimicrobial activities. Eur J
Med Chem 44:4362–4366
Remi J, Huttenbrenner A, Feddersen B, Noachtar S (2010) Carba-
mazepine but not pregabalin impairs eye control: a study on
acute objective CNS side effects in healthy volunteers. Epilepsy
Res 88:145–150
Deng XQ, Quan LN, Song MX, Wei CX, Quan ZS (2011) Synthesis
and anticonvulsant activity of 7-phenyl-6,7-dihydro-[1,2,4]tria-
zolo[1,5-a]pyrimidin-5(4H)-ones and their derivatives. Eur J
Med Chem 46:2955–2963
Deng XQ, Song MX, Zheng Y, Quan ZS (2014) Design, synthesis and
evaluation of the antidepressant and anticonvulsant activities of
triazole-containing quinolinones. Eur J Med Chem 73:217–224
Donato F, de Gomes MG, Goes AT, Seus N, Alves D, Jesse CR,
Savegnago L (2013) Involvement of the dopaminergic and
serotonergic systems in the antidepressant-like effect caused by
Sahu JK, Ganguly S, Kaushik A (2013) Triazoles: a valuable insight
into recent developments and biological activities. Chin J Nat
Med 11:456–465
Shaveta Singh A, Kaur M, Sharma S, Bhatti R, Singh P (2014)
Rational design, synthesis and evaluation of chromone-indole
and chromone-pyrazole based conjugates: identification of a
lead for anti-inflammatory drug. Eur J Med Chem 77:185–192
Strine TW, Kobau R, Chapman DP, Thurman DJ, Price P, Balluz LS
(2005) Psychological distress, comorbidities, and health behav-
iors among US adults with seizures: results from the 2002
National Health Interview Survey. Epilepsia 46:1133–1139
Sun XY, Wei CX, Chai KY, Piao HR, Quan ZS (2008) Synthesis and
anti-inflammatory activity evaluation of novel 7-alkoxy-1-
amino-4,5-dihydro[1,2,4]triazole[4,3-a]quinolines. Arch Pharm
341:288–293
4
9
-phenyl-1-(phenylselanylmethyl)-1,2,3-triazole.
3:393–400
Life
Sci
Duarte MO, Lunardelli S, Kiekow CJ, Stein AC, Muller L, Stolz E,
Rates SM, Gosmann G (2014) Phloroglucinol derivatives present
an antidepressant-like effect in the mice tail suspension test
(
TST). Nat Prod Commun 9:671–674
Sun XY, He XJ, Pan CY, Liu YP, Zou YP (2011) Synthesis and study
of the antidepressant activity of novel 4,5-dihydro-7-alkoxy(phe-
noxy)-tetrazolo[1,5-a]quinoline derivatives. Med Chem Res
21:3692–3698
Eswaran S, Adhikari AV, Shetty NS (2009) Synthesis and antimi-
crobial activities of novel quinoline derivatives carrying 1,2,4-
triazole moiety. Eur J Med Chem 44:4637–4647
123

Med Chem Res
Wang HJ, Wei CX, Deng XQ, Li FL, Quan ZS (2009) Synthesis and
evaluation on anticonvulsant and antidepressant activities of
Wouters A, Lemmens R, Dupont P, Thijs V (2014) Wake-up stroke
and stroke of unknown onset: a critical review. Front Neurol
5:153–164
5-Alkoxy-tetrazolo[1,5-a]quinazolines.
342:671–675
Arch
Pharm
Wilusz MJ, Peters RM, Cassidy-Bushrow AE (2014) Course of
depressive symptoms across pregnancy in African American
women. J Midwifery Womens Health 59:411–416
1
23