Synthesis and pharmacological evaluation of 3-aryl-3-azolylpropan-1-amines as selective triple serotonin/norepinephrine/dopamine reuptake inhibitors

Article abstract of DOI:10.1016/j.bmcl.2010.07.021

A series of 3-aryl-3-azolylpropan-1-amines was prepared and screened for its capability of inhibiting monoamine reuptake. Analogs with nanomolar potency, good human in vitro microsomal stability, and low drug-drug interaction potential were described. In

Full text of DOI:10.1016/j.bmcl.2010.07.021

Bioorganic & Medicinal Chemistry Letters 20 (2010) 5567–5571
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and pharmacological evaluation of 3-aryl-3-azolylpropan-1-amines
as selective triple serotonin/norepinephrine/dopamine reuptake inhibitors
b
b
b
b
b
Ki-Ho Lee a,b, , Chun-Eung Park , Kyung-Hyun Min , Yong-Je Shin , Coo-Min Chung , Hui-Ho Kim ,
Hae-Jeoung Yoon b, Won-Kim b, Eun-Ju Ryu b, Yu-Jin Shin b, Hyun-Sik Nam b, Jeong-Woo Cho b,
Hee-Yoon Lee a
*
a Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
b Life Science Division, SK Holdings, Daejeon 305-712, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of 3-aryl-3-azolylpropan-1-amines was prepared and screened for its capability of inhibiting
monoamine reuptake. Analogs with nanomolar potency, good human in vitro microsomal stability, and
low drug–drug interaction potential were described. In vivo models were used to evaluate the compound
19r for antidepressive, anxiolytic, and analgesic activity.
Received 7 April 2010
Revised 29 June 2010
Accepted 7 July 2010
Available online 17 August 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Depression
Antidepressant
Serotonin
Norepinephrine
Dopamine
Reuptake
Inhibitor
Currently used antidepressants generally interfere with trans-
porter-mediated reuptake of serotonin (5-HT), norepinephrine
(NE), or both.1,2 Dopaminergic transmission is also important, be-
causeadysfunctionofdopaminergicmechanismsofrewardisrelated
to anhedonia.3 Suppression of dopamine (DA) reuptake enhances
sexual function and may improve cognitive performance.1,4,5
(GSK372475, 6) also went into Phase II though failed therein in
depression.14
It can be expected that triple reuptake inhibitors will offer im-
proved efficacy in the management of depression. This Letter de-
scribes our efforts to obtain compounds with equivalent
functional activity at 5-HT, NE, and DA uptake sites, a triple
reuptake inhibitor.
Hence, the concept of 5-HT, NE, and DA triple reuptake inhibi-
tion has been explored by combination therapy with several cur-
rently available antidepressants (Fig. 1). The available data
suggest that the combination of a NDRI (norepinephrine and dopa-
mine reuptake inhibitor) bupropion (WellbutrinÒ 1) and either a
SSRI (selective serotonin reuptake inhibitor, such as fluoxetine
(ProzacÒ 2)) or a SNRI (serotonin and norepinephrine reuptake
inhibitor, such as venlafaxine (EffexorÒ 3) and duloxetine (Cymbal-
taÒ 4)) can be effective for patients unresponsive to monotherapy,
and can reduce SSRI or SNRI-associated sexual side effects.6,7
Based on these outcomes, there is currently much interest in tri-
ple reuptake inhibitors that express antidepressant actions, with-
out effect on sexual behavior and abuse liability in behavioral
models.8–12 Clinical trials showed that DOV216,303 (5) was as
effective as the SSRI citalopram in severely depressed patients
based on changes in the HAM-D.13 GSK/NeuroSearch’s NS2359
CF3
O
O
H
N
HO
H
N
Cl
N
H
MeO
Cl
1(bupropion)
2(fluoxetine)
3(venlafaxine)
Cl
Cl
Cl
O
MeO
6(NS2359)
NH
S
N
N
H
H
4(duloxetine)
5(DOV216,303)
* Corresponding author.
E-mail address: kiho.lee@sk.com (K.-H. Lee).
Figure 1. Representative antidepressants.
0960-894X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2010.07.021

5568
K.-H. Lee et al. / Bioorg. Med. Chem. Lett. 20 (2010) 5567–5571
We set out a search for triple reuptake inhibitors from the library
of SK compound collection, and identified dimethyl-(3-carbamoyl-
oxy-3-naphthalen-2-yl-propyl)-amine as having micromolar
Target compounds (Table 2) that contain the phenyl ring in-
stead of the naphthyl group were prepared via a somewhat differ-
ent synthetic route starting from the substituted benzoic acids 14
(Scheme 2).
7
binding affinity for the cerebral rat serotonin transporter.
During our exploration of compound 7, we investigated alter-
nate isostere of carbamoyloxy group. Following a preliminary sur-
vey of heterocyclic replacements for the carbamoyloxy group in 7,
we focused our medicinal chemistry efforts on the novel dimethyl-
(3-naphthalen-2yl-3-tetrazol-2-yl-propyl)-amine series such as 8.
Compound 8 contains a tetrazole ring as a surrogate for the aryloxy
group in the fluoxetine and duloxetine structures. Moreover, this
compound was an inhibitor at all three of the monoamine reuptake
transporters (Table 3).
This route had an advantage over the Mannich route as the Man-
nich reaction route showed inconsistency in the construction of a fo-
cused library. Starting with appropriately substituted benzoic acids
14, desired dimethylaminoketones 16 were synthesized via Wein-
reb amides 15 through vinyl Grignard addition followed by amine
addition.16 Ketones 16 were readily reduced to alcohols 17 and
substituted with the azole groups to afford the desired compounds
18. Next, these products were N-demethylated with chloroethyl
chloroformate to form the equivalent monomethyl amines 19.
The racemic compounds 19 could be separated into enantio-
mers by using chiral HPLC.17 Although the absolute stereochemis-
try of the chiral compounds described in the Tables 1 and 2 have
not yet been confirmed individually, scale-up preparation of chiral
isomer 19r (98% ee) using a lipase-mediated transesterification
reaction not only provided a quantity of 19r for in vivo study but
also provided information on the absolute stereochemistry of the
chiral compounds (Scheme 3).18
We set out a strategy that initially selects compounds which
show binding affinities for one of the transporters and then deter-
mines binding affinities of selected compounds for all three trans-
porters to facilitate identifying optimal triple reuptake inhibitors.
First, we determined binding affinities of compounds for cere-
bral rat serotonin transporter (rSERT) as a prescreening tool and
then evaluated uptake of 5-HT, NE, and DA into cloned human
serotonin transporter (hSERT), norepinephrine transporter (hNET),
and dopamine transporter (hDAT) for selected compounds.19
Compound 8 possessed a high affinity for cerebral rSERT and
had IC50 values of 138, 264 and 616 nM to the human SERT, NET,
and DAT, respectively.
N
NH2
O
N
N
N
O
N
N
7
8
(3-Naphthyl-3-azolyl-propyl)-methyl-amines (Table 1) were
conveniently prepared in a three- or four-step sequence as de-
scribed in Scheme 1. With variously substituted acetonaphthones
9 as starting materials, a Mannich reaction using para-formalde-
hyde and dimethylamine hydrochloride gave the 3-dimethylami-
noketones 10, which were easily converted to alcohols 11 using
sodium borohydride. The alcohols 11 were substituted with
various azoles under Mitsunobu conditions to form the desired
compounds 12. Some of these compounds were easily N-demethy-
lated with ethyl chloroformate to afford the corresponding
monomethylamines 13. The enantiomers of 13c were separated
into isomers 13d and 13e by using chiral HPLC.15
Microsomal metabolism studies of the tertiary amino derivative
8 indicated N-demethylation as one of the primary routes of metab-
olism. Based on these results, in vitro potencies of a series of (3-
naphthyl-3-azolyl-propyl)-methyl-amines for cerebral rat seroto-
nin transporter (rSERT) were measured and summarized in Table 1.
Demethylated analog, 13a showed a similar activity to 8, and
the corresponding 1-naphthyl derivative 13b was much less active.
Contrary to our expectation, microsomal stability of desmethyl
analog 13a did not improve (Table 3). The smaller methyl and lar-
ger phenyl substituents at the tetrazole ring resulted in com-
pounds (12c and 12f) with similar rSERT potency. There was a
difference in reuptake potency between the two enantiomers of
compound 13c. Isomer 13d showed higher potency than its enan-
tiomer 13e and this activity difference was consistent in all the
analogs. As another route of metabolism of 8 was found to be
hydroxylation at the naphthyl group, substitution at the 2-naph-
thyl moiety was studied to suppress the metabolism as well as to
improve the activity. While chlorine substitution at the 6-position
(12g and 13g) lowered the activity, fluorine substitution was well
tolerated (12i, 12j, 13i, and 13j). Methyl or methoxy substitution
did not seem to change the activity much (12h, 12k, 13h, 13k,
and 13l). Substitution at the 3-position (13m) showed the similar
activity to substitution at the 6-position.
When these compounds were screened for human serotonin,
norepinephrine, and dopamine transporters, none of them showed
a balance activity for all three transporters except 8 (Table 3). In
general, the inhibition potency of DAT uptake was much lower
than those of SERT and NET uptakes throughout this series. This re-
sult was also reflected in the animal model as well. When tested in
the mouse forced swimming test (FST),21 assay used to evaluate
the antidepressant agents, compound 13f did not show any activ-
ities (5.5% reduction of immobility time) at the dose of 30 mg/kg,
IP. Comparative data for compound 8 showed antidepressant-like
Table 1
Inhibitory activity of (3-naphthyl-3-azolyl-propyl)-methyl-amine series at the rat
serotonin transporter
R1
N
N
N
N
R2
*
N
R
R
R1
R2
Stereochemistry
rSERT (% inhibition)
8
13a
13b
12c
13c
13d
13e
12f
H
H
H
H
Me
H
rac
rac
rac
rac
rac
S
85.1 6.4% (at 1
l
l
l
l
l
M)a
M)a
M)a
M)a
M)a
90.4 8.5% (at 1
51.6 0.7% (at 1
85.0 6.6% (at 1
93.6 9.1% (at 1
Naphthyl-1-yl
H
H
H
H
H
H
Cl
Cl
Me
Me
F
F
F
F
Me
Me
Me
Me
Ph
Ph
H
H
H
H
H
Me
H
H
H
Me
H
Me
H
Me
H
Me
H
Me
H
Me
H
H
H
60.2 0.7% (100 nM)b
34.5 1.8% (100 nM)b
R
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
92.6 3.2% (at 1
98.4 10.9% (at 1
54.3 2.8% (at 1
52.1 10.4% (at 1
87.7 2.4% (at 1
l
M)a
13f
l
M)a
12g
13g
12h
13h
12i
13i
12j
13j
l
M)a
l
M)a
l
M)a
93.3 6.6% (at 1 l
M)a
74.1 3.6% (100 nM)b
80.1 2.9% (100 nM)b
67.5 0.6% (100 nM)b
81.3 1.3% (100 nM)b
33.6 3.7% (100 nM)b
81.2 0.7% (100 nM)b
80.2 1.5% (100 nM)b
89.9 3.9% (100 nM)b
H
Me
Me
H
H
Me
Me
12k
13k
13l
OMe
OMe
OMe
c
13m
a
Inhibition of [3H]-paroxetine binding to rat cerebral cortical membranes. Flu-
oxetine (IC50 = 12.6 nM) was used as a standard. Percent inhibition measured at a
concentration of 1 M. Carried out in triplicate.
l
b
Percent inhibition measured at the concentration of 100 nM.
3-Methoxynaphthyl.
c

K.-H. Lee et al. / Bioorg. Med. Chem. Lett. 20 (2010) 5567–5571
5569
O
O
OH
a
b
R1
N
N
R1
R1
9
10
11
c
R2
R2
N
N
N
N
N
N
N
N
d
N
R1
N
H
R1
12
13
Scheme 1. Reagents: (a) paraformaldehyde, dimethylamine.HCl, EtOH, reflux; (b) NaBH4, MeOH; (c) PPh3, DIAD, azoles, THF; (d) ethyl chloroformate, NaHCO3, and KOH.
Table 2
O
O
O
Inhibitory activity of (3-phenyl-3-azolyl-propyl)-methyl-amine series at the rat
serotonin transporter
O
a
b
OH
N
N
R1
R1
R1
R1
16
15
N
14
N
N
R"
N
c
R'
R2
*
N
R2
R2
N
R
OH
N
N
N
e
d
R2
N
N
R
R0
R00
R1
*
rSERT (% inhibition)
R1
5.9 0.2% (100 nM)b
N
19a
18b
18c
19c
19d
19e
19f
18g
19h
18i
H
H
Cl
Cl
H
Cl
H
H
H
H
H
H
H
Cl
H
H
H
H
H
H
H
H
H
Cl
Cl
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
H
H
H
H
H
H
Me
H
H
H
H
H
H
H
H
H
H
H
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
rac
S
N
R1
R1
ꢀ5.6 3.2% (100 nM)b
H
Me
Me
H
H
H
H
Me
H
Me
Me
H
Me
Me
Me
Me
Me
H
Me
H
H
H
Me
H
32.4 0.7% (at 1
41.1 1.3% (at 1
l
l
M)a
M)a
17
18
Scheme 2. Reagents: (a) N,O-dimethylhydroxylamine.HCl, CDI, TEA, THF; (b)
vinylmagnesium bromide, dimethylamine, THF; (c) NaBH4, MeOH; (d) PPh3, DIAD,
Azoles, THF; (e) chloroethyl chloroformate, DiPEA,CH2Cl2, and MeOH, reflux.
Br
10.7 3.7% (100 nM)b
15.3 4.3% (100 nM)b
3.1 0.9% (100 nM)b
ꢀ3.0 0.1% (100 nM)b
ꢀ1.7 0.0% (100 nM)b
9.5 6.3% (100 nM)b
ꢀ0.2 1.7% (100 nM)b
39.1 4.3% (100 nM)b
CF3
CF3O
tBu
PhO
BnO
Cl
H
H
O
18j
19k
18l
Cl
Me
F
OMe
OMe
Cl
Cl
Cl
Cl
Cl
Cl
Me
F
OH
O
49.2 1.6% (at 1
25.3 0.7% (at 1
l
l
M)a
M)a
Cl
Cl
Cl
Cl
Cl
Cl
a
N
N
18m
18n
18o
18p
19p
18q
19q
19r
19s
18t
19t
19u
19v
N
+
OMe
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
12.9 0.0% (100 nM)b
20
39.9 2.3% (at 1
72.0 2.5% (at 1
86.0 2.0% (at 1
69.4 1.9% (at 1
86.0 3.8% (at 1
l
l
l
l
l
M)a
M)a
M)a
M)a
M)a
21
22
N
Me
Me
Me
N
N
N
OH
61.2 2.6% (100 nM)b
20.0 0.4% (100 nM)b
d,e,f,g,h
Cl
Cl
Cl
Cl
N
H
22
NH2
Cl
Cl
Cl
Cl
Me
R
c
rac
rac
S
69.9 3.1% (at 1
81.0 2.2% (at 1
l
l
M)a
M)a
c
c
c
23
30.5 0.8% (100 nM)b
8.5 0.2% (100 nM)b
19n
H
H
Cl
R
Scheme 3. Reagents and conditions: (a) lipase PS-C, vinyl propionate, diisopropyl
ether, 40 °C, 12 h (21 20% and 22 46%); (b) K2CO3/H2O/MeOH, rt, 70%; (c) BH3-DMS,
THF, rt to reflux, 12 h; (d) (Boc)2O, TEA, CH2Cl2, rt, 77%; (e) PPh3, DIAD, 5-methyl-
tetrazole, THF 0 °C to rt, 2 h 54%; (f) 6% HCl in MeOH, rt, 4 h; (g) excess ethyl
formate, 80 °C, 12 h 83%; (h) LAH in THF.
a
Inhibition of [3H]-paroxetine binding to rat cerebral cortical membranes. Flu-
oxetine (IC50 = 12.6 nM) was used as a standard. Percent inhibition measured at a
concentration of 1 M. Carried out in triplicate.
l
b
Percent inhibition measured at a concentration of 100 nM.
[1,2,3]Triazol-2-yl.
c
pounds 18c, 18j, 18o, and 18p demonstrated that 3,4-dichloro sub-
stitution on phenyl ring was optimal to surrogate the naphthyl ring
of 8 for the high rSERT binding. In the same trend as the naphthyl
series, (S)-isomers showed the higher activity than the opposite
stereoisomers (19r vs 19s, 19u vs 19v). Substitution at the tetra-
zole ring did not affect the activity (18q and 19q). Replacing tetra-
zole ring with triazole ring was well tolerated (18t, 19t, 19u, and
19v).
activity (43.2% reduction of immobility time, p <0.05) at the same
dose.
The limited success of analogs of the naphthyl moiety was pre-
sumed due to presence of multiple aromatic groups in the com-
pounds. Therefore, a series of substituted phenyl analogs that
possess only one benzene ring in the molecules was prepared
and screened for the activity for rSERT (Table 2).
Examining the inhibition activities of the analogs with different
phenyl substituents indicated that the position, size, and nature of
the aryl substituent had significant impact on rSERT potency. Com-
Selected compounds from Table 2 along with the compounds
from Table 1 were screened for human serotonin, norepinephrine,
and dopamine transporters and summarized in Table 3. Some of

5570
K.-H. Lee et al. / Bioorg. Med. Chem. Lett. 20 (2010) 5567–5571
Table 3
the transporters from the phenyl series (18p, 19p, and 19r). When
compared to naphthyl analog 8, the 3,4-dichlorophenyl analog 18p
was over 10-fold more potent at DAT. 3,4-Dichlorophenyl moiety is
also found in structure of DOV216,303 and NS2359. So 3,4-dichlo-
rophenyl moiety within this series is important for SERT and DAT
dual binding. Compound 18p showed moderate but balanced
potencies at all three hSERT/NET/DATs but also showed poor
in vitro stability. Demethylated compound 19p was more potent
at hSERT and hNET than its dimethylamino analog 18p, which
was consistent with the previous SAR trend in the naphthyl series.
Triazole analog 19u showed similar microsomal stability (HLM t1/
2 >60 min) and rSERT affinity to 19p. However 19u displayed lower
potency to the hSERT compared to 19p. Thus maintaining 3,4-di-
chloro substituents at phenyl ring and substituting with methyl
group at tetrazole ring produced a potent chiral inhibitor 19r,
which had an excellent metabolic stability in HLM.
The data (Table 3) suggest that 19u is a relatively selective
inhibitor of NE and DA transporter, whereas 19r is a more balanced
inhibitor across all three transporters. Among the most potent ana-
logs, the reuptake potencies of compounds 19p and 19r were sim-
ilar to that of 5 (DOV216,303).22 Compound 19r was selected for
further study since 19r is a single enantiomer while 19s is a race-
mate. Compound 19r had minimal off-target activity against a pa-
Inhibitory activity of (3-aryl-3-azolyl-propyl)-methyl-amine series at the human
serotonin, norepinephrine, and dopamine transporters
hSERT
hNET
hDAT
RLMe
(t1/2
min)
HLMf
(t1/2
min)
% inhibitiona,d
IC50 (nM)
/
% inhibitionb,d
IC50 (nM)
/
% inhibitionc,d
IC50 (nM)
/
,
,
8
41%
138 nM
30%
264 nM
84%
13.3 nM
79%
37%
32%
20%
55%
12%
25%
10%
39%
39%
70%
84%
37%
234 nM
56%
20%
616 nM
10%
1240 nM
7%
3%
3
50
13a 78%
32 nM
12
49
13d 82%
13e 23%
12g 46%
13g ꢀ4%
13h 93%
12i 61%
13i 59%
12j 61%
13j 58%
12k 44%
13k 88%
13l 82%
18p 27%
279 nM
19p 35%
181 nM
19r 43%
143 nM
19u 10%
660 nM
18%
ꢀ21%
3%
7%
6%
6%
10%
36%
4%
3%
58%
78 nM
48%
116 nM
62%
58 nM
44%
3
29
>60
>60
27
>60
3
>60
56
55
>60
>60
69 nM
84%
19.8 nM
76%
nel of representative aminergic receptors (
a1, H1, M1, M3 <20% at
10 M; 5-HT2C 66% at 10 M). Compound 19r was further evalu-
l
l
14.7 nM
91.7 nM
ated for the effects of CYP inhibition: 19r showed no appreciable
inhibition against CYP1A2, CYP2C9, CYP2C19, and CYP3A4, with
2
3
5
3.1 nM
35 nM
215 nM
NTg
NTg
581 nM
72.4 nM
7340 nM
93.8 nM
IC50 >10
(IC50 6.9
l
l
M, while 19r was a moderate inhibitor against CYP2D6
M).
a
Inhibition of serotonin uptake in HEK-293 cells at, stably transfected with
Based on these data, the compound 19r was then selected for
in vivo evaluation (Table 4).
human SERT. Fluoxetine (IC50 = 3.1 nM) was used as a standard. Carried out in
duplicate.
b
Inhibition of norepinephrine uptake in MDCK cells, stably transfected with
A series of in vivo models were used to evaluate the CNS activity
of 19r: potentiation of 5-hydroxytryptophan (5-HTP, the precursor
of serotonin)-induced serotonin syndrome-like behavior (head
twitch) in mouse for 5-HT activity,23–25 FST, and tail suspension
test (TST)26–28 for antidepressant activity, mouse acetic acid-
induced writhing test (AA) for anti-pain activity,29–31 mouse
marble burying test (MB) for anxiolytic activity,32,33 and mouse
spontaneous locomotor activity test (LMA) for DA activity.34,35
The compound 19r dose-dependently increased the stereotypy
counts induced by 5-HTP with a minimal effective dose (MED) of
30 mg/kg. In agreement with serotonin reuptake data in the Ta-
ble 2, fluoxetine was the most potent in 5-HTP model (MED
3 mg/kg), whereas a 10-fold higher dose of 19r was required to sig-
nificantly enhance the effect of 5-HTP. In a similar way, venlafaxine
human NET. Desipramine (IC50 = 0.786 nM) was used as a standard. Carried out in
duplicate.
c
Inhibition of dopamine uptake in CHO-K1 cells, stably transfected with human
DAT. Nomifensine (IC50 = 16.4 nM) was used as a standard. Carried out in duplicate.
d
Percent inhibition measured at a concentration of 100 nM.
RLM, rat liver microsomes.
HLM, human liver microsomes.
NT denotes not tested.
e
f
g
the compounds were screened for metabolic stability in rat and hu-
man liver microsomes (RLM and HLM).20 The IC50 values of reup-
take inhibition were determined for representative compounds
from the naphthyl series (8 and 13a), a compound with triazole
(19u) for comparison and compounds with similar activities across
Table 4
Pharmacology of 19r compared with antidepressant agents in animal models
Value
19r
3
5
2
5-HTPa
FSTb
MEDg PO
30 (158%*)
10 (129%*)
30 (54%*)
60 (156%)
10 (18%)
3 (146%*)
MED PO
ED50 PO
10 (14.9%*)
22.2
30 (35.2%*)
38.4
50 (14.8%*)
30.1
(95% CL 16.5–29.9)
3 (59.6%*)
94.4%*
(95% CL 28.9–51.0)
7 (56.3%*)
70.2%*
82.3%*
119%* (30 PO)
139%* (60 PO)
(95% CL 16.2–55.9)
5 (33.2%*)
93.7%*
TSTc
AAd
MED PO
% inhibition at 30 SC
% inhibition at 30 IP
% change
MBe
LMAf
94.4%*
99.1%*
60.3%* (10 IP)
92% (30 PO)
142%* (90 PO)
134% (150 PO)
150%*(30 PO)
131% (60 PO)
148% (90 PO)
a
b
c
d
e
f
5-HTP potentiation of 5-HTP symptoms in mice. In parentheses, percentage of potentiation (control group: 0%).
FST forced swimming test in mice. In parentheses, percentage of immobility reduction.
TST tail suspension test in mice. In parentheses, percentage of immobility reduction.
AA acetic acid-induced writhing test in mice. Inhibition percentage of number of writhing.
MB marble burying test in mice. Inhibition percentage of number of marbles buried.
LMA locomotor activity test in mice (control group: 100%). In parentheses, doses inducing changes are indicated. *p <0.05.
MED, minimal effective dose. Doses are expressed in mg/kg, PO (oral), SC (subcutaneous) or IP (intraperitoneal).
g

K.-H. Lee et al. / Bioorg. Med. Chem. Lett. 20 (2010) 5567–5571
5571
Table 5
References and notes
Pharmacokinetic parameters of the compound 19ra after single oral and IV (intra-
venous) administration to rat
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Parameters
PO (10 mg/kg, n = 4)
IV (10 mg/kg, n = 4)
Cmax (ng/mL)
tmax (h)
t1/2 (h)
AUCall (ng h/mL)
AUCinf (ng h/mL)
CL (mL/kg/min)
Vss (L/kg)
334
3834
3. Nemeroff, C. B. Focus 2008, 6, 3.
0.75
5.48
1276
1793
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23, 178.
3.12
3833
4150
42
6.8
% Bioavailability
43.2
a
8. Breuer, M. E.; Chan, J. S.; Oosting, R. S.; Groenink, L.; Korte, S. M.; Campbell, U.;
Schreiber, R.; Hanania, T.; Snoeren, E. M.; Waldinger, M.; Olivier, B. Eur.
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HCl salt was used.
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significantly potentiated the syndrome induced by the 5-HT pre-
cursor at the dose of 10 mg/kg. DOV216,303 showed a similar effi-
cacy at the dose of 60 mg/kg.
Oral administration of 19r significantly reduced the immobility
time in the FST. Compounds 5 (DOV216,303) and 3 (venlafaxine)
were slightly less potent than 19r. In dose–response assays of
the TST, 19r induced a significant and marked reduction of mice
immobility at the dose of 3 mg/kg. Venlafaxine (3) mimicked these
actions, reaching statistical significance at the dose of 7 mg/kg.
Compound 19r induced the marked antidepressant-like effects
and was the most potent drug in both FST and TST models. Com-
pound 19r, 3, and 5 significantly reduced the number of writhes
and marbles buried at the dose of 30 mg/kg. Significant but slight
increases in spontaneous locomotor activity in mice were observed
at 1 h after the oral administration of 19r, 3, and 5 at the test doses.
Antidepressant-like activity of 19r does not appear to be due to
motor stimulation since 19r was active in the forced swim test at
doses that do not increase motor activity. On the other hand,
DOV 216,303 has been shown to have modest but statistically sig-
nificant increases in motor activity at doses that produce meaning-
ful reductions in immobility in the forced swim test.13 SSRIs and
SNRIs were reported to enhance the locomotor activity of mice ex-
posed to a novel environment.36
With promising in vitro and in vivo results in hand, pharmaco-
kinetic properties of 19r were evaluated, which is summarized in
Table 5.
After oral administration of a 10 mg/kg dose of 19r to rats, a
Cmax of 334 ng/mL was observed at 0.75 h. The elimination half-life
for 19r following oral administration was 5.48 h in rats. Compound
19r showed good oral bioavailability (F = 43.2%) and high blood
clearance (42 mL/kg/min) in rats.
In summary, we identified a series of 3-aryl-3-azolylpropan-1-
amine derivatives as triple reuptake inhibitors for the treatment
of depressive disorders. SAR studies were performed via variation
of azole group and modification of substituents on aryl group.
Based on the outcomes of in vitro studies and in animal models,
19r was identified as a lead compound for this antidepressant pro-
gram. The compound 19r was also active in animal models predic-
tive of anxiolytic and analgesic activity. Further studies on the
development of potent triple reuptake inhibitors will be reported
in due course.
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(4.6 ꢁ 250 mm); hexane/isopropanol (0.1% DEA) = 90/10; flow rate = 1 mL/
min; column temperature = 27 °C); isomer 1 (13d) 15.45 min, isomer 2 (13e)
16.79 min.
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17. HPLC separation conditions for isomers of 19q and 19t: (Chiralpak-AD column
(4.6 ꢁ 250 mm); hexane/isopropanol (0.1% DEA) = 90/10; flow rate = 1 mL/
min; column temperature = 27 °C); isomer 1 (19r) 8.64 min, isomer 2 (19s)
9.57 min; isomer 1 (19u) 8.36 min, isomer 2 (19v) 8.97 min.
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with [3H]paroxetine (PerkinElmer Life Sciences, LesUlis, France). Freshly
prepared membranes of rat frontal cortex were homogenized with a Polytron
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in incubation buffer. Membranes were incubated in triplicate with 2 nM
[3H]paroxetine and competing ligand in a final volume of 0.4 mL for 2 h at
25 °C. The incubation buffer contained 50 nM Tris–HCl (pH 7.4), 120 nM NaCl,
and 5 mM KCl. Nonspecific binding was defined with 10 mM citalopram.
Determination of [3H]5-HT, [3H]NE, and [3H]DA uptake: all tests were
conducted by MDS Pharma Services-Taiwan Ltd, Taipei, Taiwan.
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determine half-lives of up to 60 min.
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Acknowledgment
The research was supported by a grant from the Korea Health
Industry Development Institute (KHIDI).