Synthesis and evaluation of amide, sulfonamide and urea-benzisoxazole derivatives as potential atypical antipsychotics

Article abstract of DOI:10.1039/c4md00578c

In this paper, we report the optimization of a series of novel, potential antipsychotic derivatives combining potent dopamine D₂, D₃ and serotonin 5-HT_1A, 5-HT_2A receptor affinities. The pharmacological features of compound 27 are a high affinity for dopamine D₂, D₃ and serotonin 5-HT_1A, 5-HT_2A receptors. Moreover it possesses low affinity for 5-HT_2C and H₁ receptors (to reduce the risk of obesity associated with chronic treatment) and hERG channels (to reduce the incidence of torsade des pointes). Furthermore, compound 27 inhibited apomorphine-induced climbing, MK-801-induced hyperactivity and DOI-induced head twitch without observable catalepsy at the highest dose tested in mice. Taken together, among the amide derivatives, we identified compound 27 as a potential antipsychotic lead candidate.

Full text of DOI:10.1039/c4md00578c

MedChemComm
View Article Online
View Journal
CONCISE ARTICLE
Synthesis and evaluation of amide, sulfonamide
and urea – benzisoxazole derivatives as potential
atypical antipsychotics†
Cite this: DOI: 10.1039/c4md00578c
ab
a
a
b
a
Yin Chen,‡ Yu Lan,‡ Xudong Cao, Xiangqing Xu, Juecheng Zhang,
b
a
a
ab
Minquan Yu, Xin Liu, Bi-Feng Liu and Guisen Zhang*
In this paper, we report the optimization of a series of novel, potential antipsychotic derivatives combining
potent dopamine D , D and serotonin 5-HT1A, 5-HT2A receptor affinities. The pharmacological features of
compound 27 are a high affinity for dopamine D , D and serotonin 5-HT1A, 5-HT2A receptors. Moreover it
2
3
2
3
Received 29th December 2014,
Accepted 12th February 2015
possesses low affinity for 5-HT2C and H receptors (to reduce the risk of obesity associated with chronic
1
treatment) and hERG channels (to reduce the incidence of torsade des pointes). Furthermore, compound
27 inhibited apomorphine-induced climbing, MK-801-induced hyperactivity and DOI-induced head twitch
DOI: 10.1039/c4md00578c
without observable catalepsy at the highest dose tested in mice. Taken together, among the amide deriva-
www.rsc.org/medchemcomm
tives, we identified compound 27 as a potential antipsychotic lead candidate.
8–11
QT interval prolongation.
Therefore, novel drugs that pos-
Introduction
sess improved efficacy and favorable side-effect profiles are
needed.
The growing recognition that multi-receptor ligands,
which simultaneously act at multiple targets, may yield a
more desirable drug profile than selectively targeted drugs
Schizophrenia, a neuropsychiatric disorder affecting more
than 1% of the world's population, is a devastating and costly
1
disease. Typical antipsychotics (e.g., haloperidol, Fig. 1) exert
control of positive symptoms of schizophrenia by opposing
the excessive stimulation of D2 receptors resulting from
hyperactivity of mesolimbic dopaminergic projections. How-
ever, it fails to alleviate the negative symptoms such as social
has opened
therapeutics.
a
new approach for the development of
In general, research over the past decade
1
2–14
has shown that the clinical efficacy of antipsychotic drugs is
linked to a complex binding profile. Moreover, many previous
2
withdrawal, flattened affect, and cognitive deficits. Moreover,
typical antipsychotics are associated with extrapyramidal
studies have demonstrated the importance of multi-target G-
3–5
15,16
symptoms (EPS). The introduction of clozapine as the first
atypical antipsychotic (e.g., clozapine, ziprasidone and risperi-
done, Fig. 1) in 1989 represented a new development in the
treatment of schizophrenia. Atypical antipsychotics possess
potent antagonism for serotonin 5-HT and dopamine D2
protein-coupled receptors in schizophrenia.
Blockade of
the mesolimbic D receptor increases the efficacy of atypical
2
antipsychotics against positive symptoms associated with
17
schizophrenia. The D receptor seems to play a role in flexi-
3
ble behaviors, a behavioral component that is affected by
2
A
6
18
19
receptors. These drugs are effective in treating a range of psy-
chiatric symptoms. Moreover, they have fewer reported extra-
pyramidal adverse events compared to those reported with
schizophrenia.
3
D antagonism may improve cognition
2
0
and reduce the risk of causing extrapyramidal side effects.
ABT-925 is a selective dopamine D receptor antagonist that
3
7
typical antipsychotic medications. However, patients treated
has an approximately 100-fold higher in vitro affinity for
2
1
with the majority of the atypical antipsychotics have reported
clinically significant weight gain, dyslipidemia, diabetes, and
dopamine D versus D receptors. The safety and tolerability
3 2
of ABT-925 have been examined in phase 1 studies, where
ABT-925 was generally well tolerated up to the highest dose
levels tested (600 mg single dose, 500 mg once daily [QD] for
a
Systems Biology Theme, Department of Biomedical Engineering, College of Life
2
2
7
days). ABT-925 is currently undergoing phase II clinical
Science and Technology, Huazhong University of Science and Technology, Wuhan
2
2
430074, China. E-mail: gszhang@mail.hust.edu.cn; Fax: +86 27 87792170;
trials in patients with schizophrenia. The 5-HT1A receptor
Tel: +86 27 87792235
plays a crucial role in regulating psychoemotional, cognitive
b
Jiangsu Nhwa Pharmaceutical Co., Ltd., 69 Democratic South Road, Xuzhou,
23,24
and motor functions in the central nervous system.
Pre-
Jiangsu, 221116, China
clinical data indicate that 5-HT1A receptor activation contrib-
utes to the improved activity of certain atypical antipsychotic
drugs, such as effective treatment of cognitive and negative
†
Electronic supplementary information (ESI) available. See DOI: 10.1039/
c4md00578c
These authors contributed to this work equally.
‡
This journal is © The Royal Society of Chemistry 2015
Med. Chem. Commun.

View Article Online
Concise Article
MedChemComm
Fig. 1 Structures of a typical (haloperidol) and atypical antipsychotics.
3
2–35
symptoms, and decreased development of EPS in schizophre-
nia. 5-HT2A receptor antagonism is believed to contribute to
catalepsy in animal models.
affinity for dopamine D , D
receptors, and it possesses low affinity for H
1
Compound 4 possesses high
2
5
2
3
and serotonin 5-HT1A, 5-HT2A
and 5-HT2C
1
7
the atypical antipsychotic profile. Furthermore, the H
-HT2C receptors may be involved in the weight gain associ-
ated with the treatment of schizophrenia via atypical antipsy-
1
and
5
receptors (to reduce the risk of obesity associated with
chronic treatment). Furthermore, fewer preclinical adverse
events were noted with compound 4 compared with risperi-
done in assays that measured prolactin secretion and weight
gain. In the present study, we developed an amide, sulfon-
amide and urea with a semi-rigid alkylene spacer system
linked to the 4-IJ6-fluorobenzoijd]isoxazol-3-yl)piperidin-1-yl
group, which is a key chemical structure found in atypical
antipsychotics. This strategy led to the synthesis of com-
pounds 10–33 (Fig. 2), which allowed us to understand the
SAR (structure–activity relationship) and evaluate the phar-
macological efficacy. We report here the synthesis and behav-
ioral investigation of new compounds as novel and potential
antipsychotics, characterized by potent binding affinities for
2
6–29
chotic drugs.
novel antipsychotics that act on dopaminergic and serotoner-
gic receptors with a low affinity for the H and 5-HT2C recep-
Thus, the aim of our work was to develop
1
tors. Our goal was to develop a pharmacological agent that
would effectively treat the positive symptoms, the negative
symptoms and the cognitive impairment associated with
schizophrenia, without producing weight gain.
In fact, the latest effort was the development of compound
1
(Fig. 2), a 4-isoquinolinesulfonamide with a semi-rigid
alkylene spacer, classified as a multi-receptor atypical anti-
3
0,31
psychotic.
In our previous studies, compounds 2–5
exhibited obvious antipsychotic properties without observable
Fig. 2 Design of new amide derivatives.
Med. Chem. Commun.
This journal is © The Royal Society of Chemistry 2015

View Article Online
MedChemComm
Concise Article
the D , D , 5-HT , 5-HT , H , 5-HT , α and α receptors.
Percentage of inhibition (%) = (total binding − specific binding)
× 100%/(total binding
2
3
1A
2A
1
2C
1
2
Furthermore, three primary behavioral models were used to
evaluate compounds. Inhibition of apomorphine-induced
climbing, MK-801-induced hyperactivity and DOI-induced
head twitch predicted efficacy for the positive symptoms of
schizophrenia and induction of catalepsy benchmarked the
liability for extrapyramidal motor side-effects.
− nonspecific binding)
Blank experiments were carried out to determine the effect
of 5% DMSO on the binding; no such effects were observed.
Compounds were tested at least three times at six concentra-
−
5
−10
tions (10 M to 10
M), IC50 values were determined by
nonlinear regression analysis using a Hill equation curve
Chemistry
fitting. K values were calculated based on the Cheng and
i
The general strategy for the synthesis of compounds 10–31 is
summarized in Scheme 1. The N-Boc-protected piperidin-4-
ylmethanol (6a), piperidin-4-ylethanol (6b) and piperidin-3-
ylmethanol (6c) reacted with tosyl chloride to give com-
pounds 7a–c. Then, the intermediates 7a–c reacted with
Prussoff equation: K = IC /(1 + C/K ), where C represents
the concentration of the radioligands used, and K its recep-
d
tor dissociation constant was calculated for each labeled
i
50
d
ligand. Mean K values and SEM are reported for at least
i
three independent experiments. Binding affinities were
4
-IJ6-fluorobenzoijd]isoxazol-3-yl)piperidine to give the respec-
expressed as K values in Tables 1–4.
i
tive tertiary amines 8a–c. Boc removal with EA/HCl gave com-
pounds 9a–c, which reacted with acyl chlorides, sulfonyl chlo-
rides or isocyanate to yield compounds 10–33.
Selected compounds were further evaluated in vivo in mice
using apomorphine-induced climbing, MK801-induced hyper-
activity, DOI-induced head twitch and catalepsy models.
Pharmacology
Results and discussion
In vitro studies of new compounds
All of the new compounds (free bases) were dissolved in 5%
DMSO and buffer. The following specific radioligands and
In this work, our initial focus was to investigate the affinities
of urea derivative compounds on D , 5-HT and 5-HT2A
tissue sources were used: (a) serotonin 5-HT
receptor,
1
A
2
1A
3
ij H]8-OH-DPAT, rat brain cortex; (b) serotonin 5-HT recep-
receptors (Table 1, compounds 10–14). As shown in Table 1,
compounds 10 and 11 with alkyl substituents demonstrated
weak affinities for D , 5-HT and 5-HT2A receptors. It is
2A
3
tor, [ H]ketanserin, rat brain cortex; (c) serotonin 5-HT2C
3
receptor, [ H]mesulergine, rat brain cortex; (d) dopamine D
2
2
1A
3
receptor, [ H]spiperone, rat striatum; (e) dopamine D recep-
worth mentioning that compounds 12 and 13 with aromatic
substituents have improved affinities to D , 5-HT1A and
5-HT2A receptors, in contrast to compounds 10 and 11. More-
over, the compound with a chlorine (Cl) on the phenyl (com-
2 i i
pound 13, D , K = 85.6 nM; 5-HT2A, K = 6.8 nM) showed
3
3
tor, ij H]7-OH-DPAT, rat olfactory tubercle; (f) histamine H
1
2
3
receptor, [ H]mepyramine, guinea pig cerebellum; (g) adren-
3
ergic α receptor, [ H]prazosin, rat brain cortex; (h) adrener-
1
3
gic α
2
receptor, [ H]rauwolscine, rat brain cortex.
Total binding was determined in the absence of non-
specific binding and test compounds. Specific binding was
determined in the presence of test compounds. Non-specific
binding was determined as the difference between total and
specific binding.
higher affinity than the compound with a CH3 (compound
12, D , K = 178.1 nM; 5-HT , K = 26.9 nM) to D and 5-HT
2A
2
i
2A
i
2
receptors. However, the introduction of a benzyl group (com-
pound 14) resulted in a dramatic decrease in affinities for
the three receptors.
Scheme 1 Reagents and conditions: (a) TsCl, CH
2
Cl
2 3 3 3
, Et N, 0 °C rt; (b) 4-IJ6-fluorobenzoijd]isoxazol-3-yl)piperidine, Et N, CH CN, reflux, 24 h; (c)
EA/HCl; (d), acyl chloride or isocyanate, Et N, CH Cl
3
2
2
, 0 °C rt.
This journal is © The Royal Society of Chemistry 2015
Med. Chem. Commun.

View Article Online
Concise Article
MedChemComm
a
2
Table 1 Binding affinities for D , 5-HT1A and 5-HT2A receptors of compounds 10–14 and reference antipsychotics
i
Receptor affinity K ± SEM (nM)
Compound
R
1
D
2
5-HT1A
5-HT2A
b
10
>10 000
>10 000
568.6 ± 68.6
1
1
2
>10 000
>10 000
1098.2 ± 156.9
26.9 ± 3.2
1
178.1 ± 19.2
276.5 ± 29.6
1
1
3
4
85.6 ± 9.1
298.9 ± 38.6
6.8 ± 1.5
1268.2 ± 168.9
>10 000
265.3 ± 29.8
Clozapine
Risperidone
130.7 ± 15.2
2.8 ± 0.3
185.6 ± 19.1
190.2 ± 16.1
12.9 ± 1.3
0.25 ± 0.03
a
b
i i
K values are taken from three experiments, expressed as means ± SEM. The K values were not calculated because the inhibition
percentages at 10 μM were too low.
a
2
Table 2 Binding affinities for D , 5-HT1A and 5-HT2A receptors of compounds 15–21
i
Receptor affinity K ± SEM (nM)
Compound
R
2
D
2
5-HT1A
5-HT2A
b
15
16
17
>10 000
>10 000
>10 000
215.6 ± 27.8
>10 000
310.2 ± 45.2
113.8 ± 21.6
1273.8 ± 230.1
598.9 ± 65.7
1
1
8
9
86.8 ± 9.1
156.9 ± 16.3
268.7 ± 38.1
19.0 ± 1.1
71.8 ± 9.2
194.6 ± 23.5
2
2
0
1
1191.1 ± 230.1
2500
120.8 ± 13.9
>10 000
>10 000
2115.0 ± 312.1
a
b
i i
K values are taken from three experiments, expressed as means ± SEM. The K values were not calculated because the inhibition
percentages at 10 μM were too low.
Next, we investigated the effect of replacing the urea deriv-
atives with amide derivatives (Table 2, compounds 15–20). As
shown in Table 2, compounds 15 (cyclopropyl) and 16 (ter-
tiary butyl) with alkyl substituents showed weak affinities for
Furthermore, compounds 18–19 with fluorine (F) and nitro
(NO ) on the phenyl group showed higher affinity than sub-
2
stituents with hydrogen (H) and a CH O group to the D ,
2
3
5-HT1A and 5-HT2A receptors. However, the introduction of a
D
2
and 5-HT1A, and moderate affinity to the 5-HT2A receptor.
3-phenyl-2-propenoyl group (compound 21) resulted in the
Med. Chem. Commun.
This journal is © The Royal Society of Chemistry 2015

View Article Online
MedChemComm
Table 3 Binding affinities for D
Concise Article
a
2
, 5-HT1A and 5-HT2A receptors of compounds 22–33
Receptor affinity K
i
± SEM (nM)
Compound
R
3
D
2
5-HT1A
5-HT2A
b
22
2500
>10 000
>10 000
2
3
1287.1 ± 156.9
>10 000
1523.5 ± 162.1
367.6 ± 42.1
112.9 ± 18.8
15.7 ± 2.2
24
25
26
27
28
210.9 ± 25.6
190.4 ± 24.2
32.6 ± 4.5
789.2 ± 98.7
478.8 ± 68.9
21.9 ± 3.5
8.7 ± 1.0
16.9 ± 2.1
0.79 ± 0.1
589.7 ± 60.5
1011.2 ± 126.6
26.9 ± 3.6
2
3
9
0
758.8 ± 80.1
917.3 ± 115.1
1201.8 ± 134.3
135.2 ± 16.1
32.6 ± 41.9
1382.5 ± 140.5
31
1290.8 ± 136.6
165.1 ± 190.6
454.9 ± 53.2
3
3
2
3
—
—
>10 000
1099.1 ± 124.5
1366.1 ± 225.3
990.3 ± 113.3
66.8 ± 71.1
30.1 ± 4.5
a
b
K
i
values are taken from three experiments, expressed as means ± SEM. The K
i
values were not calculated because the inhibition
percentages at 10 μM were too low.
nM ± SEM) and hERG of compounds 26, 27 and reference antipsychoticsa
2 i
receptors (K
Table 4 Binding affinities for the D
3
, H
1
, 5-HT2C, α
1
and α
a
b
Receptor affinity K
i
± SEM (nM)
IC50 ± SD (nM)
Compound
D
3
H
1
5-HT2C
α
1
α
2
hERG
Ripersidone
Clozapine
15.1 ± 2.0
41.2 ± 5.1
8.1 ± 0.8
43.6 ± 5.1
25.9 ± 4.1
33.1 ± 3.6
136.8 ± 18.1
998.2 ± 12.31
7.8 ± 1.0
47.2 ± 5.4
1098.2 ± 115.2
2356.2 ± 289.2
56.8 ± 6.8
78.1 ± 9.2
568.3 ± 67.3
967.3 ± 99.1
778 ± 82.1
901 ± 12.2
1390.1 ± 162.3
3810.2 ± 415.9
340.1 ± 35.6
236.8 ± 33.1
16.6 ± 2.8
2
2
6
7
2845.2 ± 311.4
a
b
K
i
values are taken from three experiments, expressed as means ± SEM. IC50 value is the mean of 3 determinations.
loss of affinity to all three receptors. These results suggested
that an aromatic group has greater affinity to the three recep-
tors than an alkyl group.
To further explore the SAR of these compounds, we
replaced the amide derivatives with sulfonamides (Table 3,
compounds 22–33). According to Table 3, compounds 22
(phenyl) and 23 (substituent with CH on the phenyl) showed
3
weak affinities to all three receptors. Interestingly, the intro-
duction of a withdrawing groups on the phenyl group
improved the affinities to all three receptors. Compounds 24
and 25 (substituents containing a fluorine or cyanide on
the phenyl) exhibited moderated affinities for all three
This journal is © The Royal Society of Chemistry 2015
Med. Chem. Commun.

View Article Online
Concise Article
MedChemComm
receptors. Substituents with trifluoromethyl (CF ) on the phe-
Q wave and the end of the T wave on an electrocardiogram
(QT interval). Specific examples include sertindole and
3
nyl (compound 26, D , K = 32.6 nM; 5-HT , K = 21.9 nM;
2
i
1A
i
3
6
5
-HT2A, K
i
= 15.7 nM) had good affinities to all three recep-
grepafloxacin. Indeed, efforts to predict an increased risk
for long-QT syndrome have focused on assays that test hERG
channel activity. As shown in Table 4, compounds 26 and 27
exhibited weak affinities for hERG compared with risperi-
done and clozapine. Interestingly, the low affinity of 27
(IC50 = 3810.2 nM) for hERG compared with risperidone and
clozapine may decrease the propensity of these compounds
to elicit treatment-induced QT interval prolongation.
tors. Substituents with a nitro group (NO ) on the phenyl
2
(
compound 27, D , K = 8.7 nM; 5-HT , K = 16.9 nM; 5-HT ,
2 i 1A i 2A
i
K = 0.79 nM) exhibited higher affinities to all three receptors
than did those with the other withdrawing groups. Moreover,
compound 27 displayed a higher affinity for all three recep-
tors (D , K = 130.7 nM; 5-HT1A, K = 185.6 nM; 5-HT2A,
2 i i
Ki = 12.9 nM) compared with clozapine. The phenyl ring
substituted with NO in the ortho-position (compound 28, D ,
The intrinsic activity of compound 27 was selected for fur-
ther investigation based on its interaction with multiple
receptors. As shown in Table 5, 27 showed stimulatory activ-
ity in an agonist assay on D , D , 5-HT and 5-HT2A recep-
2
2
K
i
= 589.7 nM; 5-HT1A, K
i
= 1011.2 nM; 5-HT2A, K
i
=26.9 nM)
and meta-position (compound 29, D , K = 758.8 nM; 5-HT ,
2
i
1A
K = 917.3 nM; 5-HT , K = 135.2 nM) caused a dramatic
i
2A
i
2
3
1A
decrease of affinities to all three receptors in comparison to
compound 27. This indicates that affinities for the D2,
tors displayed minimal agonist activity, in all cases displaying
less than 10% of the efficacy of the reference endogenous
agonist. In an antagonist assay, 27 inhibited four receptors
5
-HT1A and 5-HT2A receptors depended on the location of the
substituent on the phenyl ring. We also investigated the
effect of replacing the phenyl ring with naphthalene and
thiophene (Table 3, compounds 30 and 31). According to
these results, compounds 30 and 31 displayed a dramatic
decrease in affinity to the D2 and 5-HT1A receptors. These
results also indicate the importance of the phenyl ring for
(D
2
, D
Taken together, these results indicate that compound 27
shows high affinity for D , D , 5-HT1A and 5-HT2A receptors,
as well as a low affinity for the H and 5-HT2C receptors.
3
, 5-HT1A and 5-HT2A) by over 95%.
2
3
1
Therefore, it was selected as a promising atypical antipsy-
chotic agent and subjected to in vivo pharmacological
characterization.
2
affinity to the D and 5-HT1A receptors. We investigated the
effect of the length of the linker between the piperidine ring
and the 4-IJ6-fluorobenzoijd]isoxazol-3-yl)piperidin-1-yl group.
As shown in Table 3, chain lengths of one (compound 27) to
two (compound 32) carbon atoms resulted in significantly
Behavioral studies
The apomorphine-induced climbing model has been classi-
cally linked to motor agitation, one of the positive symptoms
reduced D
the binding affinities for D
2
, 5-HT1A and 5-HT2A receptor binding. Therefore,
, 5-HT1A and 5-HT2A receptors are
3
7
2
of schizophrenia. As shown in Table 6, compound 27 had
−
1
dependent upon chain length. Finally, we changed the piperi-
dine ring 4-position (compound 27) to the 3-position (com-
pound 33), which caused a dramatic decrease in affinity to
an ED50 of 0.4 mg kg ; in comparison, risperidone, clozapine
and haloperidol reversed apomorphine-induced climbing
with ED50 values of 0.012, 4.52 and 0.17 mg kg ,
respectively.
−
1
the D and 5-HT receptors.
2
1A
In line with the multiple receptor targeting approaches for
the development of new antipsychotic agents, compounds 26
and 27 were selected for further tests of their binding to the
The observation that uncompetitive N-methyl-D-aspartate
NMDA) receptor antagonist MK-801 induce schizophrenic
symptoms in healthy subjects and exacerbate existing psycho-
ses in schizophrenic patients has suggested that endogenous
(
D
3
, H
for the D
that compound 27 (K = 16.6 nM) displayed an equivalently
1
and 5-HT2C receptors because they had high affinities
2
, 5-HT1A, and 5-HT2A receptors. The results showed
i
3 i
affinity to D receptors with risperidone (K = 15.1 nM). Fur-
Table 5 The activities of compound 27 and reference compounds to D
2
,
thermore, compounds 26 and 27 showed weak affinities to α
1
3
D , 5-HT1A and 5-HT2A receptors
and α adrenergic receptors (Table 4).
2
Activation
Inhibition
(10 μM, %)
(mean ± SD)
Treatment of schizophrenia with atypical antipsychotic
drugs has been associated with weight gain. Two receptors,
histamine H1 and 5-HT2C have been suggested to be
involved in this adverse event. Hence, the observation that
(
(
10 μM, %)
mean ± SD)
Receptor
Compound
(n = 3)
(n = 3)
D
2
Dopamine
Perphenazine
27
Dopamine
Spiperone
100.9 ± 1.9
—
5.9 ± 0.9
99.5 ± 5.8
—
3.7 ± 0.7
99.1 ± 8.7
—
8.2 ± 0.9
98.5 ± 8.6
—
—
compound 27 has a much lower affinity (K
i
= 2845.2 nM)
99.5 ± 10.2
100.4 ± 5.8
—
97.9 ± 4.9
95.8 ± 6.5
—
100.1 ± 9.8
98.7 ± 5.4
—
99.6 ± 3.7
100.2 ± 1.9
for H receptors than risperidone (K = 41.2 nM). As shown
1
i
D
3
in Table 4, moreover, compound 27 had weak affinity to the
-HT2C receptor (K = 998.2 nM) in comparison to risperi-
done (K = 25.9 nM). Based on the above results, compound
5
i
27
i
5-HT1A
5-HT
WAY-100635
2
7 exhibited low potential to elicit treatment-associated
27
weight gain.
5-HT2A
5-HT
Ketanserin
27
Recent studies have shown that a wide range of medica-
tions can prolong the length of time between the start of the
6.8 ± 0.7
Med. Chem. Commun.
This journal is © The Royal Society of Chemistry 2015

View Article Online
MedChemComm
Concise Article
Table 6 In vivo pharmacological profile of compound 27. Inhibition of different behavioral responses after oral administration of the test and reference
compounds in mice
a
b
c
d
Compound
APO
MK-801
DOI
CAT
CAT/APO
CAT/MK-801
2
7
0.40 (0.31–0.52)
0.012 (0.01–0.015)
4.52 (3.38–6.28)
0.17 (0.14–0.20)
0.71 (0.23–0.85)
0.013 (0.01–0.024)
2.11 (1.75–2.45)
0.14 (0.08–0.22)
0.57 (0.24–1.36)
0.038 (0.02–0.09)
—
—
43.53
0.38
55.89
0.47
108.8
31.7
12.4
2.8
61.3
29.2
26.5
3.4
Risperidone
Clozapine
Haloperidol
a
−1
b
−1
c
APO: apomorphine-induced climbing (mg kg , po). MK-801: MK-801-induced hyperactivity (mg kg , po). DOI: DOI-induced head twitch
−1
d
−1
(mg kg , po). CAT: catalepsy (mg kg , po).
dysfunction of NMDA receptor-mediated neurotransmission
synthesized, compound 27 showed high affinity for dopami-
nergic (D2 and D ) and serotonergic IJ5-HT and 5-HT2A)
3
8
might contribute to the pathogenesis of schizophrenia. It is
well known that systemic administration of MK-801 increases
3
1A
receptors and low affinity for H receptors and hERG chan-
1
3
9
dopamine cell firing rate in the brain. In particular, hyper-
activity produced by a low dose of MK-801 is dependent upon
nels. Furthermore, animal models showed that compound 27
had high potential for treating symptoms of schizophrenia
without causing catalepsy. Taken together, among the amide
derivatives, we identified compound 27 as a potential antipsy-
chotic lead candidate. Our studies demonstrate that the novel
derivative may serve as a promising antipsychotic lead and
hence pave the way for further investigation around this
chemical space.
3
9
D receptor stimulation. Thus, the hyperactivity induced by
3
MK-801 can be reduced in vivo by multi-target antipsychotic
drugs characterized by high affinity and selectivity degree for
4
0
D
3
receptor.
In this test, compound 27 significantly
inhibited MK-801-induced hyperactivity, with an ED50 value
−
1
of 0.71 mg kg (Table 6). In comparison, risperidone, cloza-
pine and haloperidol yielded ED50 values of 0.013, 2.11 and
−
1
0
.14 mg kg , respectively.
Acknowledgements
Catalepsy is often used as a measure for predicting the
incidence of extrapyramidal motor disorders. In this model,
it was clear that haloperidol had the highest propensity to
The authors gratefully acknowledge the National Science and
Technology Major Project “Key New Drug Creation and
Manufacturing Program” (2012ZX09103-101-010).
−
1
induce catalepsy (ED50 0.47 mg kg ), in agreement with the
4
1
high capacity of this drug to block the D
2
receptor. In con-
trast, compound 27 exhibited a low potential to induce cata-
References
−
1
lepsy (ED , 45.53 mg kg , Table 6). The therapeutic indices
5
0
of compound 27 based on its efficacy (apomorphine or MK-
1 D. A. Shapiro, S. Renock, E. Arrington, L. A. Chiodo,
L. X. Liu, D. R. Sibley, B. L. Roth and R. Mailman,
Neuropsychopharmacology, 2003, 28, 1400–1411.
2 H. Y. Meltzer and M. Huang, Prog. Brain Res., 2008, 172,
177–197.
8
6
01 models) and its side effects (catalepsy) were in the range
1–108, while the therapeutic indices of risperidone was
roughly 29–31. Thus, in contrast to risperidone and cloza-
pine, compound 27 had a higher threshold for inducing cata-
lepsy, which might, by analogy, translate into lower clinical
EPS liability.
3 S. R. Marde, W. C. Wirshing and T. Van Putten, Schizophr.
Res., 1991, 4, 81–90.
The in vivo efficacy of compound 27 and selected analogs
was evaluated in mice DOI ij(±)-2,5-dimethoxy-4-iodo-
amphetamine-HCl]-induced head twitch model. This model
measures blockade of head twitches induced by DOI which is
4 R. J. Baldessarini and D. Tarsy, Annu. Rev. Neurosci., 1980, 3,
23–41.
5 A. E. Boyd and S. Reichlin, Psychoneuroendocrinology,
1978, 3, 113–130.
6 J. Geddes, N. Freemantle, P. Harrison and P. Bebbington,
BMJ [Br. Med. J.], 2000, 321, 1371–1376.
7 D. Tarsy, R. J. Baldessarini and F. I. Tarazi, CNS Drugs,
2002, 16, 23–45.
8 B. J. Kinon and J. A. Liberman, Psychopharmacology,
1996, 124, 2–34.
9 H. J. Moller, CNS Drugs, 2003, 17, 793–823.
10 D. Vohora, Expert Opin. Invest. Drugs, 2007, 8, 531–538.
4
2
a 5-HT2A agonist. As shown in Table 6, compounds 27 and
−
1
−1
risperidone have a ED50 of 0.57 mg kg and 0.038 mg kg ,
respectively.
Overall, compound 27 significantly inhibited apomorphine-
induced climbing behavior, MK-801-induced hyperactivity
and DOI-induced head twitch. Compound 27 also demon-
strated a low propensity to induce unwanted extrapyramidal
motor disturbances at therapeutically useful doses.
1
1 S. H. Schultz, S. W. North and C. G. Shields, Am. Fam.
Physician, 2007, 75, 1821–1829.
Conclusion
1
2 R. Morphy, C. Kay and Z. Rankovic, Drug Discovery Today,
2004, 9, 641–651.
In summary, we describe the synthesis and pharmacological
evaluation of a series of amide derivatives of benzisoxazole as
potential multi-target antipsychotics. Among the derivatives
13 R. Morphy and Z. Rankovic, J. Med. Chem., 2005, 48,
6523–6543.
This journal is © The Royal Society of Chemistry 2015
Med. Chem. Commun.

View Article Online
Concise Article
MedChemComm
1
4 R. Morphy and Z. Rankovic, Curr. Pharm. Des., 2009, 15,
87–600.
29 G. P. Reynolds, M. J. Hill and S. L. Kirk, J. Psychopharmacol.,
2006, 20, 15–18.
5
1
1
5 H. Y. Meltzer, Curr. Opin. Pharmacol., 2004, 4, 53–57.
6 E. H. Wong, F. I. Tarazi and M. Shahid, Pharmacol. Ther.,
30 P. Zajdel, K. Marciniec, A. Maślankiewicz, G. Satała,
B. Duszyńska, A. J. Bojarski, A. Partyka, M. Jastrzębska-Więsek,
D. Wróbel, A. Wesołowska and M. Pawłowski, Bioorg. Med.
Chem., 2012, 20, 1545–1556.
31 P. Zajdel, A. Partyka, K. Marciniec, A. J. Bojarski, M. Pawłowski
and A. Wesołowska, Future Med. Chem., 2014, 6, 57–75.
32 Y. Chen, X. Q. Xu, X. Liu, M. Q. Yu, B.-F. Liu and
G. S. Zhang, PLoS One, 2012, 7, e35186.
33 Y. Chen, X. Q. Xu, X. Liu, B.-F. Liu and G. S. Zhang, Arch.
Pharm., 2012, 345, 859–869.
34 Y. Chen, S. L. Wang, X. Q. Xu, X. Liu, M. Q. Yu, S. Zhao,
S. C. Liu, Y. L. Qiu, T. Zhang, B.-F. Liu and G. S. Zhang,
J. Med. Chem., 2013, 56, 4671–4690.
35 Y. Chen, Y. Lan, S. L. Wang, X. Q. Xu, X. Liu, M. Q. Yu, B.-F. Liu
and G. S. Zhang, Eur. J. Med. Chem., 2014, 74, 427–439.
36 M. Recanatini, E. Poluzzi, M. Masetti and D. P. F. Cavalli A,
Med. Res. Rev., 2005, 25, 133–166.
37 H. S. Kim, G. S. Rhee, S. Oh and W. K. Park, Behav. Brain
Res., 1999, 100, 135–142.
38 A. C. Lahti, M. A. Weiler, B. A. Tamara Michaelidis,
A. Parwani and C. A. Tamminga, Neuropsychopharmacology,
2001, 25, 455–467.
39 S. Murase, J. M. Mathe, J. Grenhoff and T. H. Svensson,
J. Neural Transm.: Gen. Sect., 1993, 91, 13–25.
2
010, 126, 173–185.
1
1
1
2
2
7 H. Y. Meltzer, S. Matsubara and M. A. Lee, J. Pharmacol. Exp.
Ther., 1989, 251, 238–246.
8 G. K. Gross, K. Wicke and U. Drescher, Naunyn-
Schmiedeberg's Arch. Pharmacol., 2013, 386, 155–166.
9 D. J. Watson, C. A. Marsden, M. J. Millan and K. C. Fone,
Int. J. Neuropsychopharmacol., 2012, 15, 471–484.
0 E. Bézard, S. Ferry, U. Mach, H. Stark, L. Leriche, T. Boraud,
C. Gross and P. Sokoloff, Nat. Med., 2003, 9, 762–767.
1 H. Geneste, W. Amberg, G. Backfisch, A. Beyerbach,
W. M. Braje, J. Delzer, A. Haupt, C. W. Hutchins, L. L. King,
D. R. Sauer, L. Unger and W. Wernet, Bioorg. Med. Chem.
Lett., 2006, 16, 1934–1937.
2
2 L. Redden, B. Rendenbach-Mueller, W. M. Abi-Saab,
D. A. Katz, A. Goenjian, W. Z. Robieson, Y. Wang, S. L. Goss,
N. Greco and M. D. Saltarelli, J. Clin. Psychopharmacol.,
2
011, 31, 221–225.
3 Y. Ohno, Cent. Nerv. Syst. Agents Med. Chem., 2010, 10,
48–157.
4 M. Politis, K. Wu, C. Loane, N. P. Quinn, D. J. Brooks,
S. Rehncrona, A. Bjorklund, O. Lindvall and P. Piccini, Sci.
Transl. Med., 2010, 38, 38–46.
2
2
1
2
2
5 M. J. Millan, J. Pharmacol. Exp. Ther., 2000, 295, 853–861.
6 W. K. Kroeze, S. J. Hufeisen, B. A. Popadak, S. M. Renock,
S. Steinberg, P. Ernsberger, K. Jayathilake, H. Y. Meltzer and
B. L. Roth, Neuropsychopharmacology, 2003, 28, 519–526.
7 S. F. Kim, A. S. Huang, A. D. Snowman, T. Teuscher and
S. H. Snyder, Proc. Natl. Acad. Sci. U. S. A., 2007, 104,
40 L. Leriche, J. C. Schwartz and P. Sokoloff, Neuropharmacology,
2003, 45, 174–181.
41 X. Xiberas, J. L. Martinot, L. Mallet, E. Artiges, C. Loc'H,
B. Maziere and M. L. Paillere-Martinot, Br. J. Psychiatry,
2001, 179, 503–508.
42 I. Gyertyán, B. Kiss, K. Sághy, J. Laszy, G. Szabó, T. Szabados,
L. I. Gémesi, G. Pásztor, M. Zájer-Balázs, M. Kapás,
E. Á. Csongor, G. Domány, K. Tihanyi and Z. Szombathelyi,
Neurochem. Int., 2011, 59, 925–935.
2
2
3
456–3459.
8 P. R. Buckland, B. Hoogendoorn, C. A. Guy, S. K. Smith and
S. L. Coleman, Am. J. Psychiatry, 2005, 162, 613–615.
Med. Chem. Commun.
This journal is © The Royal Society of Chemistry 2015