Triazolyl azabicyclo[3.1.0]hexanes: A class of potent and selective dopamine D3 receptor antagonists

Article abstract of DOI:10.1002/cmdc.201000026

Herein we report a detailed description of the structure-activity relationships for a novel series of "C-linked" 1,2,4- triazolylazabicyclo[3.1.0]hexanes. These derivatives are endowed with very high in vitro affinity and selectivity for the dopamine D

Full text of DOI:10.1002/cmdc.201000026

DOI: 10.1002/cmdc.201000026
Triazolyl Azabicyclo[3.1.0]hexanes: a Class of Potent and
Selective Dopamine D3 Receptor Antagonists
Giorgio Bonanomi,[a] Simone Braggio,[a] Anna Maria Capelli,[b] Anna Checchia,[a]
Romano Di Fabio,[a] Carla Marchioro,[b] Luca Tarsi,[a] Giovanna Tedesco,[b] Silvia Terreni,[a]
Angela Worby,[c] Christian Heibreder,[d] and Fabrizio Micheli*[a]
Herein we report a detailed description of the structure–activi-
ty relationships for novel series of “C-linked” 1,2,4-
mine D3 receptor. An optimization with respect to undesired
affinity toward the hERG potassium channel is also reported.
Members of this compound series also show excellent in vitro
and in vivo pharmacokinetic properties.
a
triazolylazabicyclo[3.1.0]hexanes. These derivatives are endow-
ed with very high in vitro affinity and selectivity for the dopa-
Introduction
In 1990, Sokoloff et al. first reported the cloning and characteri-
zation of the dopamine (DA) D3 receptor subtype.[1] The ex-
pression pattern of D3 mRNA in rat and human brain are simi-
lar, with high expression levels primarily in areas of the limbic
system. Different anatomical,
The screening cascade associated with the progression of
these new chemical entities (NCEs) for their biological charac-
terization has been described in detail previously.[11,16] All NCEs
were assayed for their agonist and antagonist properties with
pharmacological, and genetic
findings suggest that the DA D3
receptor might be involved in
Parkinson’s disease, schizophre-
nia, and drug addiction.[2] The
specific location of the DA D3 re-
ceptor in both the rodent and
human brain, the alterations in
the expression of the D3 recep-
tor after exposure to drugs of
abuse, and growing preclinical
evidence suggest that selective
DA D3 receptor antagonists are
suitable candidates for the phar-
macotherapeutic management
of drug addiction.[3]
Among the many research
groups in this field,[2–8] GlaxoS-
Figure 1. Selective DA D3 receptor antagonists recently reported by GSK.
mithKline (GSK) has actively con-
tributed to the discovery of se-
[a] Dr. G. Bonanomi, Dr. S. Braggio, Dr. A. Checchia, Dr. R. Di Fabio, Dr. L. Tarsi,
Dr. S. Terreni, Dr. F. Micheli
lective DA D3 receptor antagonists.[9–16] Some recently disclosed
compounds are shown in Figure 1. Derivative 5 belongs to a
series of azabicyclo[3.1.0]hexanes that are endowed with very
good in vitro affinity and selectivity, and which show a high
degree of efficacy in preclinical models of drug addiction.[16]
Herein we report studies carried out to understand the role of
the sulfur atom in the “linker/spacer”[5,17] region of 5, together
with the associated biological results. These changes, consider-
ing both the differences in the molecular orbitals and in the
electronic content of the atoms involved, might have played a
profound effect in the “antagonist region”[18] where the hydro-
gen bond acceptor sits.
Neurosciences Centre of Excellence
GlaxoSmithKline Medicines Research Centre
Via Fleming 4, 37135 Verona (Italy)
Fax: (+39)045-8218196
E-mail: fabrizio.e.micheli@gsk.com
[b] Dr. A. M. Capelli, Dr. C. Marchioro, Dr. G. Tedesco
Molecular Discovery Research
GlaxoSmithKline Medicines Research Centre
Via Fleming 4, 37135 Verona (Italy)
[c] Dr. A. Worby
Molecular Discovery Research, GlaxoSmithKline, NFSP, Harlow (UK)
[d] Dr. C. Heibreder
Reckitt Benckiser Pharmaceuticals, Richmond VA 23235 (USA)
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F. Micheli et al.
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a functional GTPgS assay expressing the human DA D3 recep-
tor. Subsequently, 100-fold selectivity versus both the DA D2 re-
ceptor (using D2 functional assays) and the human ether-ꢁ-go-
go (hERG) potassium channel (using the dofetilide binding
assay) was requested in order to obtain a sufficiently broad
preclinical therapeutic window to minimize potential adverse
effects associated with these molecular targets.
Furthermore, to ensure that the selected templates are en-
dowed with appropriate pharmacokinetic (PK) and developa-
bility characteristics from the beginning of the exploration and
screening cascade, NCEs were also assayed in generic develop-
ability screens such as Cypex bactosome P450 inhibition assays
and rat and human in vitro clearance (Cli) assays with liver mi-
crosomes. In vivo PK, including brain penetration, was also
evaluated for selected derivatives[11,16] in rat. To make a proper
comparison with the described products, all the compounds
reported herein are optically pure and were prepared by start-
ing from the optically active (1S,5R)-1-[4-(trifluoromethyl)-
phenyl]-3-azabicyclo[3.1.0]hexane as described below.
Scheme 2. Synthesis of the “O-linked” derivative. Reagents and conditions:
a) Et3N, THF, 808C (reflux), 4 h, 95%; b) 1n HCl in Et2O, THF, room tempera-
ture, 0.5 h, (quant); c) 56, NaH, DMF, 608C, 3 h.
Almost all the “C-linked” derivatives were prepared accord-
ing to the general Scheme 1, whereas the “O-linked” derivative
was prepared as shown in Scheme 2. Experimental details are
described below in the Experimental Section or are available in
the patent literature.[19,20] Biological results are listed in
Tables 1–3.
Table 1. Functional activity at the human DA D3 receptor and selectivity
for phenyl derivatives.
fpKi[a]
Compd
X
hD3–GTPgS
hD2–GTPgS
hERG pIC50
ClogD[b]
5
6
7
8
9
S
9.2
8.6
7.2
8.4
8.1
6.8
<5.5
6.5
6.5
6.6
6.2
6.1
6.2
5.9
6.7
4.1
3.8
4.6
3.4
4.1
CH2
C(CH3)2
CF2
O
[a] Functional pKi obtained from the GTPgS functional assay; SEM for D3
GTPgS and hERG data sets is ꢀ0.1; SEM for the D2 GTPgS data sets is
ꢀ0.2. [b] Determined with ACDLogD 7.4, v.11.
pivotal role in hydrogen bonding; therefore, this property
should potentially contribute to the binding activities of the
various derivatives, with the caveat that all other parameters in
the molecule are left unchanged. For this reason, four different
alternative templates were carefully designed to study their
electronic properties in silico through ab initio methods. The
sulfur atom was subsequently replaced by a methylene unit, a
gem-dimethyl group, a CF2 moiety and an oxygen atom. To
simplify the calculations, considering that the side chain would
have been the same for all the scaffolds, truncated systems
were analyzed as depicted in Figure 2.
Scheme 1. General synthetic approach to derivatives 6–8 and 10–46 (R=H,
F, Me). Reagents and conditions: a) NH2NH2·H2O, CH3OH, D, 608C (reflux),
3 h; b) 49, K2CO3, 608C (reflux), overnight; c) supported OsO4, NaIO4, THF,
room temperature, overnight; d) 52, NaBH(OAc)3, AcOH, THF, room tempera-
ture, 2 h.
Results and Discussion
The potential role of the thiotriazole moiety as hydrogen bond
acceptor in the series of compound 5 has been previously de-
tailed[16] considering the ability of the nitrogen atoms of this
peculiar heterocycle to interact with hydrogen bond donors lo-
cated at an appropriate distance and with a certain geometry
within the DA D3 receptor model.
A protocol based on a sequential semiempirical ab initio ge-
ometry optimization within Spartan[21] was used to model the
templates. In particular, the starting conformations for each
template (generated with Omega2[22]) were submitted to an in-
itial semiempirical geometry optimization using AM1, followed
by two runs of ab initio geometry optimization using the Har-
tree–Fock STO-3G and 6-31G* basis sets, respectively. A final
The electron density available on the triazole system, influ-
enced by the nature of adjacent atoms, is expected to play a
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Triazolyl Azabicyclo[3.1.0]hexanes
Figure 2. Electrostatic potential maps for templates listed in Table 1. Electrostatic potentials (measured in kcalmolꢁ1) are mapped on the electronic density
surface of the atoms (at an isosurface level of 0.002 electronsAUꢁ3).
single-point energy calculation was carried out using B3LYP
density functional theory with a 6-31G* basis set. The electro-
static potential (measured in kcalmolꢁ1) was finally mapped
onto the electronic density surface of the atoms (at an isosur-
face level of 0.002 electronsAUꢁ3) as depicted in Figure 2. Of
particular interest is the electrostatic potential around the ni-
trogen atom a to the substitution, as this atom, more than
others, reflects the changes in the electron density. It can be
clearly appreciated that, as expected, there is a certain degree
of variation with respect to the original sulfur derivative and
that such variation might produce different affinities at the DA
D3 receptor.
the electron-withdrawing (ꢁI) capacity of the sulfur atom, a
property which is, however, slightly compensated by its meso-
meric (+M) electron-donating properties. Nonetheless, the
aforementioned enrichment in electrostatic potential does not
improve the affinity of derivative 6 relative to the original
sulfur derivative 5 despite the fact that both compounds share
a similar ClogD value, suggesting that the added availability of
electrons in the region does not strengthen the hydrogen
bond that is already present and working “properly” to provide
high affinity. The further increase in ClogD and steric bulk
(compound 7), however, is detrimental to affinity, leading to a
100-fold decrease in binding potential; unfortunately the bulki-
ness of the system cannot be easily dissected from its lipophi-
licity and therefore it is difficult to understand which of the
two aspects, if any in particular, plays the major role in bind-
ing. Furthermore, it is likely that the introduction of such a
bulky substituent makes it difficult for the compound to adopt
the bioactive conformation. The introduction of the strong
electron-withdrawing gem-fluoro moiety removes electrons
from the system (Dꢂ+2 kcalmolꢁ1), and a decrease in affinity
was observed for derivative 8. The drop in affinity was quite
dramatic with respect to derivative 5, but not too high relative
to derivative 6, which has a similar ClogD value and a poten-
tially similar overall bulkiness. The introduction of the oxygen
atom (electronegativity=3.44, compound 9), despite a strong
ꢁI effect, is compensated by a robust +M effect considering
the overall result illustrated in Figure 2 on the electron density
(Dꢂꢁ2 kcalmolꢁ1). However, compound 9 showed a decrease
in affinity of ~10-fold with respect to 5 despite an identical
ClogD value and about a half log unit decrease with respect
to 6. Accordingly, excluding derivative 7 from this analysis for
The only two products that share similar values are com-
pounds 6 and 7, which respectively carry the methylene and
the gem-dimethyl groups; nonetheless, both compounds were
synthesized to gain further information which may shed light
on the additional parameters that govern the primary binding
affinity. It was previously shown[16] that in the specific thiotria-
zole series, there is a general trend in DA D3 activity versus cal-
culated logD (ClogD), with “ideal” values in the range of 3–4.
Derivatives 6–9 fall within this range, with the exception of
compound 7, which positions itself in the descending arm of
the formerly reported parabolic curve. Finally, derivative 7 is
also the only compound that shows a greater steric hindrance
in the specific region analyzed.
Replacement of the thioether with a methylene unit (com-
pound 6) enriches the electron density in the region around
the triazole nitrogen atom (Dꢂꢁ5 kcalmolꢁ1), but it does not
make a significant change in the electronegativity of the
system (2.58 for thioether versus 2.55 for methylene). This is
because the carbon atom is almost “neutral” with respect to
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707

F. Micheli et al.
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the reasons mentioned above, these results suggest that for
these specific derivatives, once the hydrogen bond is formed
in the DA D3 receptor, a further change in the electronic prop-
erties of the nitrogen atom involved does not primarily address
the affinity issue, whereas it does appear that this decrease
from compound 5 to 9 is related mainly to the electronegativi-
ty of the group attached to the triazole, suggesting an overall
participation of the ring system to the affinity potential. Inter-
estingly, this effect does not translate directly to the affinity of
the compounds for the DA D2 receptor, for which the methyl-
ene group (compound 6) is the only substitution capable of
abolishing potency at this receptor, with the activity of all
other derivatives (7–9) being nearly identical.
Considering its good affinity at the desired target and this
very interesting observation related to the abolishment of the
undesired affinity for the DA D2 receptor, we decided to further
investigate the properties of derivative 6 along the screen-
ing cascade. Accordingly, the in vitro PK properties were
assayed; IC50 values for all major cytochrome P450 isoforms
ents could range from 1 to 4 to determine whether, in this spe-
cific series as well, a correlation with DA D3 affinity is present,
as in the thiotriazole series. It is apparent that the derivatives
with the best overall activity do fall within the previously de-
scribed “ideal” ClogD range (3–4), with some of these endow-
ed with high nanomolar affinity (compounds 12, 15, 20, and
21). In this series, a further important aspect of this exploration
is the knowledge gained about the role played by the substitu-
ents in hERG activity. In comparing regioisomers 12 and 13, it
is quite evident that the 2-methyl group of derivative 12 plays
a much more important role than the 6-methyl group of 13 in
decreasing hERG affinity. This also appears to be the case in re-
spectively comparing compound 18 against derivative 17.
From these results, one may hypothesize that the presence
of a methyl group a to the attachment point of the heteroaro-
matic ring might distort the coplanarity of the biaryl system,
leading to an increased dihedral angle between the two moiet-
ies. This may decrease the potential p stacking previously de-
scribed[11,16] in the hERG channel model. To maximize the affini-
tested
(CYP1A2,
CYP2C9,
CYP2C19, CYP2D6, and CYP3A4)
were >5 mm, and Cli values
in both human and rat were
Table 2. Functional activity at the human DA D3 receptor and selectivity for “C-linked” derivatives.
moderately
low
(0.6
and
re-
0.8 mLminꢁ1 [g protein]ꢁ1
,
spectively). Consequently, com-
pound 6 was assayed for its
in vivo properties in rats,[23]
where it demonstrated a good
overall profile with a confirmed
low blood clearance (Clb:
fpKi[a]
Compd
R
hD3–GTPgS
hD2–GTPgS
hERG pIC50
ClogD[b]
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
4-pyridazinyl
7.5
7.7
8.0
7.7
7.3
8.3
7.4
7.2
7.6
7.6
8.2
8.2
7.3
8.2
8.0
8.5
8.1
8.6
8.4
8.2
8.3
8.4
8.0
8.2
8.4
8.8
7.9
8.5
8.2
8.0
6.4
<5.5
6.8
<5.5
<5.5
6.1
<5.5
5.8
<5.5
<5.5
6.2
4.9
6.0
5.1
5.8
6.2
5.9
5.5
6.1
5.7
5.6
7.0
6.7
5.3
5.9
6.6
7.4
6.6
6.6
6.5
6.9
7.0
6.6
6.1
6.6
7.2
6.4
6.2
5.8
7.3
5.4
1.0
2.2
2.8
2.4
2.6
4.2
2.4
1.8
1.8
2.4
3.5
3.1
1.4
4.0
4.4
4.6
3.6
3.8
3.8
4.8
4.5
3.8
4.1
3.1
3.2
3.7
3.8
4.1
4.8
3.2
9 mLminꢁ1 kgꢁ1),
a
relatively
5-methyl-2-pyrazinyl
2-methyl-3-pyridinyl
6-methyl-3-pyridinyl
2-methyl-6-trifluoromethyl-3-pyridinyl
2-methyl-5-quinolinyl
2,4-dimethyl-1,3-oxazol-5-yl
2-methyl-1,3-thiazol-5-yl
2,4-dimethyl-1,3-thiazol-5-yl
4-methyl-1,3-thiazol-5-yl
3-thienyl
high distribution volume (Vd:
8.9 Lkgꢁ1) leading to a half-life
(t1/2) greater than 12 h, and good
observed bioavailability (F=
60%).
Given these promising results,
priority was given to a full explo-
ration of the “C-linked” series. In
agreement with the previously
described[16] exploration of the
thiotriazole series, some selected
heteroaromatic groups were
considered as substituents of
the right-hand side of the tem-
plate on the basis of their ClogD
value, while the 4-trifluorome-
thylphenyl group was kept con-
1-methyl-2-pyrrolyl
1,3,5-trimethylpyrazol-4-yl
2-chlorophenyl
6.1
<5.5
6.4
3-chlorophenyl
4-chlorophenyl
<5.5
<5.5
6.2
<5.5
<5.5
<5.5
<5.5
<5.5
6.0
6.3
<5.5
6.1
6.1
6.1
2-methyloxyphenyl
3-methyloxyphenyl
4-methyloxyphenyl
4-trifluoromethyloxyphenyl
2-fluorophenyl
3-fluorophenyl
4-fluorophenyl
3-cyanophenyl
4-cyanophenyl
stant
on
the
azabicyclo-
[3.1.0]hexane moiety.
2,4-difluorophenyl
3,5-difluorophenyl
3,4-difluorophenyl
2,4-dichlorophenyl
tert-butyl
The results of this investiga-
tion are listed in Table 2. The
first round of compounds for
this exploration (10–22) was
chosen so that the ClogD values
of the heteroaromatic substitu-
<5.5
6.3
[a] Functional pKi obtained from the GTPgS functional assay; SEM for D3 GTPgS and hERG data sets is ꢀ0.1;
SEM for the D2 GTPgS data sets is ꢀ0.2. [b] Determined with ACDLogD 7.4, v.11.
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Triazolyl Azabicyclo[3.1.0]hexanes
ty for the DA D3 receptor and to
better investigate the aforemen-
tioned hypothesis related to
hERG activity, a second round of
Table 3. Functional activity at the human DA D3 receptor and selectivity for homologated “C-linked” deriva-
tives.
substitution was planned.
A
series of phenyl derivatives 23–
38 with ClogD values in the
range of 3–5 was chosen, and a
systematic exploration of the
substitution pattern was per-
formed. It is evident from the re-
sults listed in Table 2 that nearly
all the derivatives prepared had
functional activity at the DA D3
receptor >8; the selectivity ach-
ieved at the DA D2 receptor was
remarkable, being nearly 100-
fold or greater for all the NCEs
prepared. On the other hand,
the SAR analysis with respect to
the hERG channel was more dif-
fpKi[a]
Compd
R
hD3–GTPgS
hD2–GTPgS
hERG pIC50
ClogD[b]
40
41
42
43
44
45
46
phenyl
8.6
7.9
7.7
8.6
8.7
8.6
8.8
6.7
6.1
<5.5
6.3
6.4
6.1
6.0
5.6
5.0
6.9
7.4
7.0
7.1
4.1
2.6
2.1
4.3
5.0
4.1
4.0
5-methyl-2-pyrazinyl
4-methyl-1,3-oxazol-5-yl
2-chlorophenyl
4-chlorophenyl
3-methyloxyphenyl
2,4-difluorophenyl
6.4
[a] Functional pKi obtained from the GTPgS functional assay; SEM for D3 GTPgS and hERG data sets is ꢀ0.1;
SEM for the D2 GTPgS data sets is ꢀ0.2. [b] Determined with ACDLogD 7.4, v.11.
ficult to interpret: while in the single chloro derivative series
(23–25) the role of the twist angle between the two aryl sys-
tems is evident (with the 2-chloro compound much less active
than the corresponding 4-chloro derivative), the same is not
true for the methoxy compounds 26–28, with the 2- and 4-me-
thoxy derivatives being nearly equipotent with respect to
hERG affinity. Conversely, no major conclusions could be made
in the fluoro series (30–32) considering that all three dihedral
angles are similar because of the small fluorine atom. Further
studies were therefore carried out to better characterize the
system within the channel model; these results are reported
further below.
and hERG selectivity, but it is slightly more active at the DA D2
receptor yet still retains almost 100-fold selectivity. The intro-
duction of substituents with lower ClogD values (compounds
41 and 42) decreased the primary activity at the desired
target, and this decrease was paralleled by a reduction in off-
target activity. The mono-substituted phenyl derivatives 43–45
showed remarkable affinity and selectivity at the dopaminergic
targets, but decreased selectivity versus the hERG channel,
while the di-substituted derivative 46 showed almost nanomo-
lar DA D3 affinity with 100-fold selectivity over DA D2 and 50-
fold selectivity over the hERG channel.
The increase in length of derivative 40 did not significantly
modify its PK properties. IC50 values for all major P450 isoforms
tested (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) were
>10 mm, and Cli values in both human and rat were moderate-
ly low (1.3 and 0.5 mLminꢁ1 [g protein]ꢁ1, respectively). The
in vivo profile in rat was similar to those of the previous deriva-
tives. The clearance in blood was relatively higher (Clb:
23 mLminꢁ1 kgꢁ1), but was compensated by a high distribution
volume (Vd: 10.2 Lkgꢁ1) leading to a moderately long half-life
(t1/2 =6 h); bioavailability was very high as well (F=84%).
Finally, to answer to the remaining open question regarding
the various responses to hERG affinity for some derivatives
(such as 23 versus 25 and 43 versus 44 with respect to 26
versus 28), we decided to use the hERG channel model as pre-
viously described.[11,16] The docking of some above-mentioned
compounds in the channel could provide hints for a rational
explanation of their behavior. As can be appreciated in
Figure 3, in which compound 44 is shown, the aromatic por-
tion linked to the [3.1.0] template interacts through p stacking
with Tyr652, the basic nitrogen atom is hydrogen bonded to
Ser624, and the aromatic portion linked to the triazole is
buried in a Phe-rich region.
The introduction of a second halogen atom on the phenyl
group (compounds 35–38) led to the identification of a very
interesting derivative 37 endowed with 100-fold selectivity
over the DA D2 receptor and 500-fold selectivity over the hERG
channel. In agreement with the screening cascade, the com-
pound was characterized for its in vitro PK profile. IC50 values
for all major P450 isoforms tested (CYP1A2, CYP2C9, CYP2C19,
CYP2D6, and CYP3A4) were >5 mm, with the exception of low
CYP1A2 and Cli values in both human and rat (0.5 and
<0.5 mLminꢁ1 [g protein]ꢁ1, respectively). The in vivo PK profile
of 37 in rat was also quite interesting because, in agreement
with the previously tested derivative 6, it showed low clear-
ance in blood (Clb: 5 mLminꢁ1 kgꢁ1) and a relatively high distri-
bution volume (Vd: 7.4 Lkgꢁ1) leading to a long half-life (t1/2
18 h); bioavailability was also excellent (F=94%).
>
Finally, to complete the exploration, a simple alkyl group
was tested (compound 39). In this case as well, the compound
was potently active at the DA D3 receptor and showed high se-
lectivity over the DA D2 receptor and the hERG channel. A fur-
ther step in this line of exploration is related to linker length,
and therefore a longer chain was prepared. The results of this
investigation are listed in Table 3.
A similar pose is shown in Figure 4 for the “shorter” linker
para-methoxy derivative 28, for which the same types of inter-
action are observed. Considering these potential docking
The unsubstituted phenyl derivative 40 showed a profile
identical to compound 6 in terms of DA D3 receptor affinity
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709

F. Micheli et al.
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of the halogenated derivatives with respect to the alkoxy de-
rivatives, the aromatic portion of the former series is much
more “locked” in the phenylalanine region of the channel than
the corresponding group in the more hydrophilic alkoxy series.
Consequently, any subtle variation of the environment might
have a much more profound effect on the chlorinated com-
pounds than on the methoxy derivatives. However, no defini-
tive answer is available at the current status of the exploration.
Conclusions
A rational exploration of the role of the sulfur atom in the pre-
viously described thiotriazole series[16] has been reported. A
range of substitutions was described, and a detailed SAR was
reported for this new “carbon-linked” series. Among the com-
pounds reported, novel DA D3 receptor antagonists with high
potency and selectivity over the DA D2 and hERG channel were
disclosed. In particular, derivatives 37 and 40 showed an excel-
lent PK profile in rat, with high bioavailability and long half-life,
making them ideal compounds for further progression along
the screening cascade into animal models of drug addiction.
Figure 3. Interactions of compound 44 (yellow) in the hERG channel models.
The backbone ribbon of the pore domain is included, but those of the S5
and S6 helices have been removed for clarity. 4 K Monte Carlo steps, 1 K
minimization steps, AMBER*FF; each pose re-minimized with 10 K steps and
AMBER*FF.
modes, we hypothesize that in both cases the presence of an
ortho substituent on the aromatic ring might increase the twist
angle between the phenyl group and the triazole moiety. Such
an arrangement might disfavor the docking of the aromatic
portion in that specific region as previously stated. Unexpect-
edly, this happened only for the chlorinated and not for the
alkoxy derivatives, as previously discussed and reported in
Tables 2 and 3.
Experimental Section
g-[35S]GTP functional binding assay in cell membranes ex-
pressing hD3 receptors
In vitro functional studies were performed according to the follow-
ing g-[35S]GTP protocol. Cells used in the study are Chinese ham-
ster ovary (CHO) cells stably expressing the appropriate receptor.
Cell membranes were prepared as follows: Cell pellets were resus-
pended in 10 volumes of buffer (50 mm HEPES, 1 mm EDTA, adjust-
ed to pH 7.4 with KOH); on the day of cell harvest, the following
proteases were added to give the homogenization buffer: 1 mm
leupeptin (Sigma L2884), 5000ꢂstock=5 mgmLꢁ1 in buffer;
25 mgmLꢁ1 bacitracin (Sigma B0125), 1000ꢂstock=25 mgmLꢁ1 in
buffer; 1 mm PMSF, 1000ꢂstock=17 mgmLꢁ1 in 100% EtOH; 2 mm
pepstain A, 1000ꢂstock=2 mm in 100% DMSO. The cells were ho-
mogenized by 2ꢂ15 s bursts in a 1 L glass Waring blender in a
class 2 biohazard cabinet. The resulting suspension was centri-
fuged at 500 g for 20 min (Beckman T21: 1550 rpm). The superna-
tant was withdrawn with a 25 mL pipette, aliquoted into pre-chil-
led centrifuge tubes and centrifuged at 48000 g for 30 min to
pellet the membrane fragments (Beckman T1270: 23000 rpm). The
final 48000 g pellet was resuspended in homogenization buffer
(fourfold the volume of the original cell pellet) followed by vortex-
ing for 5 s, and was then homogenized in a dounce homogenizer
(10–15 strokes). The preparation was distributed into appropriately
sized aliquots (200–1000 mL) in polypropylene tubes and stored at
ꢁ808C. The protein content of the membrane preparation was
evaluated by the Bradford protein assay. The final highest concen-
tration of test drug was 3 mm in the assay, and 11-point serial dilu-
tion curves (1:4 in 100% DMSO) were carried out using a Biomek
FX. The test drug at 1% total assay volume (TAV) was added to a
solid, white, 384-well assay plate. 50% TAV of pre-coupled (i.e.,
90 min at 48C) membranes (5 mgwellꢁ1) were added, along with
wheat-germ agglutinin (WGA)–polystyrene scintillation proximity
At this point, considering that the docking experiments
cannot provide a clear explanation of the experimental results,
it can only be postulated that, given the higher ClogD values
Figure 4. Interactions of compound 28 (yellow) in the hERG channel models.
The backbone ribbon of the pore domain is included, but those of the S5
and S6 helices have been removed for clarity. 4 K Monte Carlo steps, 1 K
minimization steps, AMBER*FF; each pose re-minimized with 10 K steps and
AMBER*FF.
assay (SPA) beads (RPNQ0260, Amersham; 0.25 mgwellꢁ1
) in
20 mm HEPES pH 7.4, 100 mm NaCl, 10 mm MgCl2, 60 mgmLꢁ1 sap-
onin, and 30 mm GDP. The third addition was a 20% TAV addition
of either buffer, (agonist format) or EC80 final assay concentration
710
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ChemMedChem 2010, 5, 705 – 715

Triazolyl Azabicyclo[3.1.0]hexanes
of agonist (Quinelorane) prepared in assay buffer (antagonist
format). The assay was started by the addition of 29% TAV of g-
[35S]GTP 0.38 nm final (37 MBqmLꢁ1, 1160 Cimmolꢁ1, Amersham).
After all additions, assay plates were spun for 1 min at 1000 rpm.
Assay plates were counted on a PerkinElmer Viewlux instrument
equipped with a 613/55 filter for 5 min, between 2 and 6 h after
the final addition. The effect of the test drug over the basal level
generates an EC50 value through an iterative least-squares curve-fit-
ting program, expressed in the table as pEC50 (ꢁlogEC50). The ratio
between the maximal effect of the test drug and that of the full
agonist Quinelorane generates the intrinsic activity (IA) value (IA=
1: full agonist, IA<1: partial agonist); fpKi values of test drug are
calculated from the IC50 value generated by the “antagonist
format” experiment, using the Cheng–Prusoff equation: fKi =IC50/
1+([A]/EC50) for which [A] is the concentration of the agonist in
the assay, and EC50 is the agonist EC50 value obtained in the same
experiment; fpKi is defined as ꢁlogfKi.
of the compound had been metabolized by 30 min and this corre-
sponded to a Cli value of 0.5 mLminꢁ1 [g liver]ꢁ1. The upper limit
was 50 mLminꢁ1 [g liver]ꢁ1
.
Chemistry
NMR spectra were obtained with Varian INOVA spectrometers (300,
400, and 500 MHz). Chemical shift (d) values are expressed in ppm,
and peak multiplicities are expressed as follows: singlet (s), doublet
(d), doublet of doublets (dd), triplet (t), multiplet (m), broad (br).
All MS measurements were performed with a Micromass Platform
LCZ (Waters, Manchester, UK) mass spectrometer operated in posi-
tive electrospray ionization mode. For LC–MS detection, the follow-
ing analytical conditions were used: column: Zorbax SB-C18, 4.6ꢂ
50 mm (1.8 mm); mobile phase: 5 mm NH4CO2CH3 + 0.1% formic
acid/CH3CN + 0.1% formic acid, gradient: 97:3 ! 36:64 v/v in
3.5 min, ! 10:90 in 3.5 min, flow rate: 2.0 mLminꢁ1; detection:
DAD, l 210–350 nm; MS: ES+.
P450 Cypex assay
All compounds are optically pure and were prepared using (1S,5R)-
1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane. The enan-
tiomeric purity of each single enantiomer obtained after prepara-
tive chromatography on chiral columns was always verified by ana-
lytical column chromatography. For example, enantiomeric excess
was measured on the separated enantiomers by SFC analytical
techniques; typical conditions are derived from Chiralpak AD-H
column (25ꢂ0.46 cm) with EtOH (+0.1% isopropylamine) 15% as
modifier, flow rate: 2.5 mLminꢁ1, P=180 bar at 358C with detec-
tion at l 220 nm. The purity of the compounds reported herein
was established through HPLC methodology, and all reported com-
pounds have a purity of >95%.
Inhibition (IC50) of human CYP450 isoforms 1A2, 2C9, 2C19, 2D6,
and 3A4 was determined by using CypexTM bactosomes expressing
the major human P450s. A range of test compound concentrations
(0.1, 0.2, 0.4, 1, 2, 4, and 10 mm) were prepared in CH3OH and pre-
incubated at 378C for 10 min in 50 mm potassium phosphate
buffer (pH 7.4) containing recombinant human CYP450 microsomal
protein (0.1 mgmLꢁ1; Cypex Ltd., Dundee, UK) and probe–fluores-
cent substrate. The final concentration of solvent was between 3
and 4.5% of the final volume. Following pre-incubation, NADPH-re-
generating system (7.8 mg glucose-6-phosphate, 1.7 mg NADP, and
6 U glucose-6-phosphate dehydrogenase per mL of 2% (w/v)
NaHCO3; 25 mL) was added to each well to start the reaction. The
generation of the fluorescent metabolite was then measured over
a time course of 10 min by using a Spectrafluor Plus plate reader.
The rate of metabolite production (AFUminꢁ1) was determined at
each concentration of compound and converted into a percentage
of the mean control rate using Magellan (Tecan software). The IC50
value of each compound was determined from the slope of the
plot using GraFit v.5 (Erithacus Software, UK). Miconazole was
added as a positive control to each plate. CYP450 isoform sub-
strates used were ethoxyresorufin (ER, 1A2, 0.5 mm); 7-methoxy-4-
triflouromethylcoumarin-3-acetic acid (FCA, 2C9, 50 mm); 3-butyryl-
7-methoxycoumarin (BMC, 2C19, 10 mm); 4-methylaminomethyl-7-
methoxycoumarin (MMC, 2D6, 10 mm); diethoxyflourescein (DEF,
3A4, 1 mm); and 7-benzyloxyquinoline (7-BQ, 3A4, 25 mm). The test
was performed in three replicates.
Considering the in-house experience in this series, only 1H NMR
spectra were routinely acquired to confirm the identity of the com-
pounds. In cases of ambiguity, 2D NMR correlation spectroscopy
(COSY) or gradient correlation spectroscopy (gCOSY) experiments
were performed. 13C NMR data are reported for derivative 40.
(1S,5R)-3-[4-(4-methyl-5-phenyl-4H-1,2,4-triazol-3-yl)butyl]-1-[4-
(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
ride (6): K2CO3 (3.1 mmol) and benzhydrazide (3.1 mmol) were
added to solution of N,N’-dimethyl-5-hexenimidamide·HCl
hydrochlo-
a
(3.1 mmol) in CH3OH (20 mL). The solution was heated at reflux for
24 h. Volatiles were evaporated in vacuo, and the crude was dis-
solved in CH2Cl2, washed with H2O and dried over Na2SO4. After fil-
tration and concentration to dryness in vacuo, the crude was puri-
fied by column chromatography to give 196 mg 4-methyl-3-(4-
penten-1-yl)-5-phenyl-4H-1,2,4-triazole. The compound was dis-
solved in THF/H2O (7.5:1.5 v/v) and OsO4 (4% solution in H2O,
0.04 mmol) and NaIO4 (2.6 mmol) were added to the mixture. The
solution was stirred overnight at room temperature. H2O was
added, and the product was extracted with CH2Cl2. The organic
phase was separated, dried over Na2SO4, and filtered. Volatiles
were evaporated in vacuo to give 178 mg 4-(4-methyl-5-phenyl-4H-
1,2,4-triazol-3-yl)butanal as an oil, which was used in the subse-
quent step without further purification. A mixture this deriva-
tive (0.38 mmol), (1S,5R)-1-[2-fluoro-4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hexane (0.28 mmol), NaBH(OAc)3 (0.28 mmol), and
AcOH in THF (anhydrous, 2 mL) was stirred at room temperature
for 2 h. The organic phase was washed with 1n NaOH, dried over
Na2SO4, and filtered. The filtrate was concentrated in vacuo, and
the crude was purified by column chromatography to give 38 mg
of the free base of compound 6. HCl (0.085 mmol, 1m in Et2O) was
added to a solution of this material in CH2Cl2 (0.2 mL), the solvent
was evaporated in vacuo, and the material thus obtained was tritu-
Intrinsic clearance (Cli) assay
Intrinsic clearance (Cli) values were determined in rat and human
liver microsomes. Test compounds (0.5 mm) were incubated at
378C for 30 min in 50 mm potassium phosphate buffer (pH 7.4)
containing 0.5 mg microsomal protein per mL. The reaction was
started by the addition of cofactor (NADPH, 8 mgmLꢁ1). The final
concentration of solvent was 1% of the final volume. Aliquots
(50 mL) were taken at 0, 3, 6, 9, 15, and 30 min, quenched with
CH3CN containing an appropriate internal standard, and analyzed
by HPLC–MS–MS. Cli values were determined from the first-order
elimination constant by nonlinear regression using GraFit v.5 (Eri-
thacus Software, UK), corrected for the volume of the incubation
and assuming 52.5 mg microsomal protein per gram liver for all
species. Values for Cli are expressed as mLminꢁ1 [g liver]ꢁ1. The
lower limit of Cli quantification was determined to be when <15%
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711

F. Micheli et al.
MED
rated with Et2O to give 38 mg of the corresponding hydrochloride
as a white, slightly hygroscopic solid. H NMR (300 MHz, CDCl3): d=
2H), 7.63–7.74 (m, 5H), 7.45–7.55 (m, 2H), 4.07–4.20 (m, 1H), 3.92
(s, 3H), 3.78–3.89 (m, 1H), 3.65–3.74 (m, 1H), 3.57–3.65 (m, 1H),
3.23–3.36 (m, 2H), 2.24–2.38 (m, 1H), 1.92–2.02 (m, 2H), 1.74–1.88
(m, 2H), 1.61 (s, 6H), 1.51–1.61 (m, 1H), 1.26–1.35 ppm (m, 1H); MS
(ESI): m/z (%) 469 (100) [M+H]+.
1
7.73–7.70 (m, 2H), 7.67–7.60 (m, 4H), 7.57–7.52 (m, 2H), 4.1 (brd,
J=11.0 Hz, 1H), 3.89 (brm, 1H), 3.62 (brm, 1H), 3.72 (s, 3H), 3.38
(t, J=7.3 Hz, 2H), 3.00 (t, J=7.4 Hz, 2H), 2.41 (m, 1H), 1.97 (m, 4H),
1.48 (m, 1H), 1.37 ppm (m, 1H); MS (ESI): m/z (%) 459 (100)
[M+H]+.
(1S,5R)-3-[4,4-difluoro-4-(4-methyl-5-phenyl-4H-1,2,4-triazol-3-
yl)butyl]-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
1
hydrochloride (8): H NMR (300 MHz, CD3OD): d=10.31 (brs, 1H),
(1S,5R)-3-{3-[(4-methyl-5-phenyl-4H-1,2,4-triazol-3-yl)oxy]prop-
7.75 (d, J=7.6 Hz, 2H), 7.70 (d, J=8.0 Hz, 2H), 7.57–7.65 (m, 3H),
7.49 (d, J=8.0 Hz, 2H), 4.11 (dd, J=11.0 Hz, 5.4 Hz, 1H), 3.79 (s,
3H), 3.74–3.83 (m, 1H), 3.64–3.73 (m, 1H), 3.50–3.61 (m, 1H), 3.23–
3.43 (m, 2H), 2.58–2.77 (m, 2H), 2.26–2.35 (m, 1H), 2.02–2.21 (m,
2H), 1.55–1.69 (m, 1H), 1.17–1.32 ppm (m, 1H); MS (ESI): m/z (%)
477 (100) [M+H]+.
yl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hy-
drochloride (9): A mixture of (1S,5R)-1-[4-(trifluoromethyl)phenyl]-
3-azabicyclo[3.1.0]hexane (0.6 mmol), [(3-bromopropyl)oxy]-(1,1-di-
methylethyl)dimethylsilane (0.92 mmol), Et3N (185 mg, 1.83 mmol),
and NaI (20 mg) in THF (2 mL) was stirred at room temperature for
20 h. The reaction mixture was concentrated in vacuo, H2O was
added, and the aqueous phase was extracted with EtOAc. The
organic phase was dried over Na2SO4 and filtered. The filtrate
was concentrated in vacuo, and the crude was purified by column
chromatography give (1S,5R)-3-(3-{[(1,1-dimethylethyl)(dimethyl)-
silyl]oxy}propyl)-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
(54) in 60% yield. HCl (1n, 2 mL) was added to the compound fol-
lowed by THF (2 mL), and the reaction mixture was stirred at room
temperature for 1 h. The reaction mixture was concentrated in va-
cuo, and the solid was washed with Et2O (3ꢂ10 mL), dissolved in
CH3OH (2 mL), and eluted through a strong cation-exchange (SCX)
cartridge (eluent: NH3, 0.5m in CH3OH) to give the deprotected al-
cohol intermediate 55. At the same time, 4-methyl-3-(methylsul-
fonyl)-5-phenyl-4H-1,2,4-triazole (56) was prepared. MeI (303 mg,
2.13 mmol) was added dropwise to a solution of the commercially
available 4-methyl-5-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-thione
(340 mg, 1.78 mmol) in EtOH (2 mL). The reaction mixture was
stirred at reflux for 30 min. The white solid was filtered, washed
with NaOH (1m) and H2O, and extracted with CH2Cl2. The organic
phase was dried over Na2SO4 and filtered. The filtrate was concen-
trated in vacuo to give a white solid (260 mg); 240 mg (1.17 mmol)
of this intermediate were dissolved in CH2Cl2 (2 mL), and mCPBA
(604 mg, 3.5 mmol) was added portionwise. The reaction mixture
was stirred at room temperature for 4 h. EtOAc was added to com-
plete dissolution followed by saturated aqueous NaHCO3, and the
aqueous phase was extracted with EtOAc. The combined organic
phases were dried over Na2SO4 and filtered. The filtrate was con-
centrated in vacuo to give the title compound (260 mg) as a white
solid. A mixture of 56 (0.28 mmol), 55 (0.28 mmol), and NaH
(0.42 mmol) in DMF (2 mL) was stirred at 608C for 8 h. The reaction
mixture was concentrated in vacuo, H2O was added, and the aque-
ous phase was extracted with EtOAc. The organic phase was dried
over Na2SO4 and filtered. The filtrate was concentrated in vacuo,
and the crude was purified by column chromatography to give the
free base in 30% yield. HCl (1m in Et2O) was added to a solution
of this material in CH2Cl2 (0.2 mL), the solvent was evaporated in
vacuo, and the material thus obtained was triturated with Et2O to
give the title compound as a white, slightly hygroscopic solid.
1H NMR (300 MHz, CD3OD): d=7.81 (d, J=7.6 Hz, 2H), 7.8 (t, J=
7.6 Hz, 1H), 7.73 (t, J=7.6 Hz, 2H), 7.67 (d, J=8.0 Hz, 2H), 7.52 (d,
J=8.0 Hz, 2H), 4.74 (t, J=7.4 Hz, 2H), 4.22 (d, J=11.0 Hz, 1H), 3.94
(d, J=10.8 Hz, 1H), 3.76 (d, J=10.8 Hz, 1H), 3.71 (s, 3H), 3.7 (d, J=
10.8 Hz, 1H), 3.57 (t, J=7.3 Hz, 2H), 2.46 (m, 2H), 2.36 (m, 1H), 1.59
(m, 1H), 1.36 ppm (m, 1H); MS (ESI): m/z (%) 443 (100) [M+H]+.
Other C-linked derivatives were prepared as reported above for de-
rivative 6.
(1S,5R)-3-{4-[4-methyl-5-(4-pyridazinyl)-4H-1,2,4-triazol-3-yl]bu-
tyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane hy-
1
drochloride (10): H NMR (400 MHz, CD3OD): d=9.67 (s, 1H), 9.51
(d, J=5.6 Hz, 1H), 8.23 (dd, J=5.6 Hz, 2.0 Hz, 1H), 7.67 (d, J=
8.3 Hz, 2H), 7.51 (d, J=8.3 Hz, 2H), 4.17 (d, J=10.8 Hz, 1H), 3.9 (s,
3H), 3.89 (d, J=10.7 Hz, 1H), 3.71 (d, J=10.8 Hz, 1H), 3.67 (d, J=
10.8 Hz, 1H), 3.39 (brt, J=7.0 Hz, 2H), 3.12 (brt, J=7.0 Hz, 2H),
2.34 (brm, 1H), 1.99 (brs, 4H), 1.51 (brm, 1H), 1.36 ppm (brm,
1H); MS (ESI): m/z (%) 443 (100) [M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(5-methyl-2-pyrazinyl)-4H-1,2,4-triazol-
3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
1
[3.1.0]hexane hydrochloride (11): H NMR (300 MHz, CD3OD): d=
9.17 (m, 1H), 8.69 (m, 1H), 7.66 (d, J=8.3 Hz, 2H), 7.51 (d, J=
8.3 Hz, 2H), 4.19 (m, 1H), 4.07 (m, 3H), 3.88 (m, 1H), 3.67 (m, 2H),
3.39 (m, 2H), 3.08 (m, 2H), 2.66 (m, 3H), 2.35 (m, 1H), 1.96 (m, 4H),
1.49 (m, 1H), 1.34 ppm (m, 1H); MS (ESI): m/z (%) 457 (100)
[M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(2-methyl-3-pyridinyl)-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (12): 1H NMR (400 MHz, CD3OD): d=8.68 (dd, J=
4.9 Hz, 1.0 Hz, 1H), 7.95 (dd, J=7.8 Hz, 1.0 Hz, 1H), 7.68 (d, J=
8.3 Hz, 2H), 7.54 (dd, J=7.8 Hz, 5.4 Hz, 1H), 7.52 (d, J=8.3 Hz, 2H),
4.17 (m, 1H), 3.90 (m, 1H), 3.70 (m, 2H), 3.49 (s, 3H), 3.39 (t, J=
7.9 Hz, 2H), 2.99 (t, J=6.4 Hz, 2H), 2.49 (s, 3H), 2.35 (m, 1H), 1.97
(m, 4H), 1.42 ppm (m, 2H); MS (ESI): m/z (%) 456 (100) [M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(6-methyl-3-pyridinyl)-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (13): 1H NMR (300 MHz, CD3OD): d=8.83 (s, 1H),
8.24 (d, J=8.3 Hz, 1H), 7.69 (d, J=8.3 Hz, 1H), 7.67 (d, J=8.3 Hz,
2H), 7.51 (d, J=8.3 Hz, 2H), 4.16 (m, 1H), 3.88 (m, 1H), 3.74 (s, 3H),
3.71 (m, 2H), 3.38 (m, 2H), 3.01 (t, J=6.3 Hz, 2H), 2.71 (s, 3H), 2.35
(m, 1H), 1.97 (m, 4H), 1.47 (m, 1H), 1.38 ppm (m, 1H); MS (ESI): m/
z (%) 456 (100) [M+H]+.
(1S,5R)-3-(4-{4-methyl-5-[2-methyl-6-(trifluoromethyl)-3-pyridin-
yl]-4H-1,2,4-triazol-3-yl}butyl)-1-[4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hexane hydrochloride (14): 1H NMR (400 MHz,
[D6]DMSO): d=10.38 (brs, 1H), 8.13 (d, J=8.0 Hz, 1H), 7.91 (d, J=
8.0 Hz, 1H), 7.70 (d, J=8.3 Hz, 2H), 7.49 (d, J=8.3 Hz, 2H), 4.07 (d,
J=11.0 Hz, 1H), 3.73 (d, J=10.7 Hz, 1H), 3.59–3.68 (m, 1H), 3.47–
3.56 (m, 1H), 3.43 (s, 3H), 3.14–3.49 (m, 2H), 2.78–2.94 (m, 2H),
2.52 (s, 3H), 2.23–2.35 (m, 1H), 1.72–1.95 (m, 4H), 1.67–1.73 (m,
1H), 1.15–1.25 ppm (m, 1H); MS (ESI): m/z (%) 525 (100) [M+H]+.
(1S,5R)-2-methyl-5-[4-methyl-5-(4-{-1-[4-(trifluoromethyl)phenyl]-
3-azabicyclo[3.1.0]hex-3-yl}butyl)-4H-1,2,4-triazol-3-yl]quinoline
hydrochloride (15): 1H NMR (300 MHz, CD3OD): d=8.32 (d, J=
7.6 Hz, 1H), 8.25 (d, J=8.8 Hz, 1H), 8.02 (t, J=7.6 Hz, 1H), 7.84 (d,
(1S,5R)-3-[4-methyl-4-(4-methyl-5-phenyl-4H-1,2,4-triazol-3-yl)-
pentyl]-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (7): 1H NMR (400 MHz, CD3OD): d=7.74–7.82 (m,
712
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ChemMedChem 2010, 5, 705 – 715

Triazolyl Azabicyclo[3.1.0]hexanes
J=7.3 Hz, 1H), 7.68 (d, J=8.3 Hz, 2H), 7.64 (d, J=8.8 Hz, 1H), 7.53
(d, J=8.3 Hz, 2H), 4.07–4.28 (m, 1H), 3.81–4.00 (m, 1H), 3.61–3.83
(m, 2H), 3.53 (s, 3H), 3.41 (t, J=7.2 Hz, 2H), 3.03 (t, J=6.3 Hz, 2H),
2.84 (s, 3H), 2.29–2.45 (m, 1H), 1.92–2.11 (m, 4H), 1.35–1.54 ppm
(m, 2H); MS (ESI): m/z (%) 506 (100) [M+H]+.
1H), 3.37 (s, 3H), 3.19–3.38 (m, 2H), 2.75–2.87 (m, 2H), 2.26–2.34
(m, 1H), 1.72–1.93 (m, 4H), 1.60–1.70 (m, 1H), 1.09–1.30 ppm (m,
1H); MS (ESI): m/z (%) 475 (100) [M+H]+.
(1S,5R)-3-{4-[5-(3-chlorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]-
butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (24): 1H NMR (400 MHz, [D6]DMSO): d=10.51 (brs,
1H), 7.76 (brs, 1H), 7.70 (d, J=8.3 Hz, 2H), 7.63 (m, 3H), 7.49 (d,
J=8.3 Hz, 2H), 4.02 (d, J=11.0 Hz, 1H), 3.71 (d, J=10.7 Hz, 1H),
3.63 (m, 4H), 3.42 (m, 2H), 3.26 (m, 2H), 2.85 (m, 2H), 2.29 (m, 1H),
1.89 (m, 2H), 1.79 (m, 2H), 1.73 (m, 1H), 1.19 ppm (m, 1H); MS
(ESI): m/z (%) 475 (100) [M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(2-methyl-1,3-thiazol-5-yl)-4H-1,2,4-tria-
zol-3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (17): 1H NMR (300 MHz, [D6]DMSO):
d=10.52 (brs, 1H), 8.13 (s, 1H), 7.71 (d, J=8.2 Hz, 2H), 7.50 (d, J=
8.2 Hz, 2H), 4.05 (m, 1H), 3.71 (s, 3H), 3.62 (m, 4H), 3.50 (m, 2H),
3.25 (m, 2H), 2.83 (t, J=7.4 Hz, 2H), 2.30 (m, 1H), 1.84 (m, 2H),
1.76 (m, 3H), 1.19 ppm (m, 1H); MS (ESI): m/z (%) 462.0 (100)
[M+H]+.
(1S,5R)-3-(4-{4-methyl-5-[2-(methyloxy)phenyl]-4H-1,2,4-triazol-
3-yl}butyl)-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
1
(1S,5R)-3-{4-[5-(2,4-dimethyl-1,3-thiazol-5-yl)-4-methyl-4H-1,2,4-
triazol-3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane (18): 1H NMR (400 MHz, [D6]DMSO): d=10.47 (brs,
1H), 7.70 (d, J=8.3 Hz, 2H), 7.50 (d, J=8.3 Hz, 2H), 4.05 (m, 1H),
3.71 (m, 1H), 3.62 (m, 1H), 3.50 (m, 1H), 3.49 (s, 3H), 3.24 (m, 2H),
2.81 (t, J=7.4 Hz, 2H), 2.68 (s, 3H), 2.30 (s, 3H), 2.29 (m, 1H), 1.83
(m, 4H), 1.70 (m, 1H), 1.19 ppm (m, 1H); MS (ESI): m/z (%) 476
(100) [M+H]+.
[3.1.0]hexane hydrochloride (26): H NMR (300 MHz, CD3OD): d=
7.63–7.72 (m, 3H), 7.53 (d, J=8.3 Hz, 2H), 7.48 (d, J=7.8 Hz, 1H),
7.27 (d, J=8.0 Hz, 1H), 7.19 (t, J=7.8 Hz, 1H), 4.01–4.27 (m, 1H),
3.90 (s, 3H), 3.80–3.91 (m, 1H), 3.63–3.79 (m, 2H), 3.56 (s, 3H),
3.35–3.43 (m, 2H), 2.94–3.07 (m, 2H), 2.30–2.42 (m, 1H), 1.88–2.08
(m, 4H), 1.44–1.53 (m, 1H), 1.33–1.44 ppm (m, 1H); MS (ESI): m/z
(%) 471 (100) [M+H]+.
(1S,5R)-3-(4-{4-methyl-5-[3-(methyloxy)phenyl]-4H-1,2,4-triazol-
(1S,5R)-3-{4-[4-methyl-5-(4-methyl-1,3-thiazol-5-yl)-4H-1,2,4-tria-
zol-3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (19): 1H NMR (300 MHz, [D6]DMSO):
d=10.38 (brs, 1H), 9.27 (s, 1H), 7.70 (d, J=8.2 Hz, 2H), 7.49 (d, J=
8.2 Hz, 2H), 4.05 (m, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 3.49 (s, 3H),
3.41 (m, 1H), 3.24 (m, 2H), 2.82 (t, J=7.2 Hz, 2H), 2.40 (s, 3H), 2.29
(m, 1H), 1.83 (m, 4H), 1.69 (m, 1H), 1.20 ppm (m, 1H); MS (ESI): m/
z 462 (100) [M+H]+.
3-yl}butyl)-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (27): H NMR (300 MHz, CD3OD): d=
1
7.67 (d, J=8.2 Hz, 2H), 7.48–7.60 (m, 3H), 7.18–7.30 (m, 3H), 3.89
(s, 3H), 3.79–3.98 (m, 1H), 4.03–4.28 (m, 1H), 3.74 (s, 3H), 3.60–3.79
(m, 2H), 3.35–3.43 (m, 2H), 2.97–3.06 (m, 2H), 2.30–2.41 (m, 1H),
1.89–2.05 (m, 4H), 1.42–1.51 (m, 1H), 1.32–1.43 ppm (m, 1H); MS
(ESI): m/z (%) 471 (100) [M+H]+.
(1S,5R)-3-(4-{4-methyl-5-[4-(methyloxy)phenyl]-4H-1,2,4-triazol-
3-yl}butyl)-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (28): 1H NMR (300 MHz, [D6]DMSO):
d=10.3 (brs, 1H), 7.7 (d, J=8.0 Hz, 2H), 7.6 (d, J=8.3 Hz, 2H), 7.5
(d, J=8.0 Hz, 2H), 7.1 (d, J=8.3 Hz, 2H), 4.05 (d, J=11.0 Hz, 1H),
3.6–3.7 (m, 1H), 3.6 (s, 3H), 3.5–3.6 (m, 1H), 3.45–3.58 (m, 1H),
3.19–3.33 (m, 2H), 2.85 (t, J=6.8 Hz, 2H), 2.3 (m, 1H), 1.7–1.9 (m,
4H), 1.6 (m, 1H), 1.2 ppm (m, 1H); MS (ESI): m/z (%) 471 (100)
[M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(3-thienyl)-4H-1,2,4-triazol-3-yl]butyl}-1-
[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane hydrochlo-
1
ride (20): H NMR (300 MHz, [D6]DMSO): d=10.79 (brs, 1H), 8.21 (s,
1H), 7.80–7.87 (m, 1H), 7.69 (d, J=8.3 Hz, 2H), 7.57 (d, J=5.1 Hz,
1H), 7.49 (d, J=8.3 Hz, 2H), 3.96–4.08 (m, 1H), 3.74 (s, 3H), 3.29–
3.84 (m, 3H), 3.16–3.29 (m, 2H), 2.89 (t, J=7.2 Hz, 2H), 2.22–2.33
(m, 1H), 1.6–1.95 (m, 5H), 1.10–1.25 ppm (m, 1H); MS (ESI): m/z
447 (100) [M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(1-methyl-1H-pyrrol-2-yl)-4H-1,2,4-tria-
zol-3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (21): 1H NMR (300 MHz, [D6]DMSO):
d=10.53 (brs, 1H), 7.70 (d, J=8.3 Hz, 2H), 7.49 (d, J=8.3 Hz, 2H),
7.02–7.08 (m, 1H), 6.55 (d, J=2.4 Hz, 1H), 6.22 (t, J=2.4 Hz, 1H),
3.97–4.13 (m, 1H), 3.74 (s, 3H), 3.66–3.77 (m, 1H), 3.52–3.67 (m,
2H), 3.60 (s, 3H), 3.14–3.32 (m, 2H), 2.86 (t, J=6.8 Hz, 2H), 2.25–
2.34 (m, 1H), 1.75–1.94 (m, 4H), 1.69–1.77 (m, 1H), 1.16–1.24 ppm
(m, 1H); MS (ESI): m/z 444 (100) [M+H]+.
(1S,5R)-3-[4-(4-methyl-5-{4-[(trifluoromethyl)oxy]phenyl}-4H-
1,2,4-triazol-3-yl)butyl]-1-[4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hexane hydrochloride (29): 1H NMR (300 MHz,
[D6]DMSO): d=10.15 (brs, 1H), 7.83 (d, J=8.0 Hz, 2H), 7.71 (d, J=
8.0 Hz, 2H), 7.56 (d, J=8.0 Hz, 2H), 7.50 (d, J=8.0 Hz, 2H), 4.07 (d,
J=9.8 Hz, 1H), 3.69–3.79 (m, 1H), 3.61 (s, 3H), 3.58–3.67 (m, 1H),
3.45–3.58 (m, 1H), 3.19–3.33 (m, 2H), 2.83 (t, J=6.8 Hz, 2H), 2.27–
2.34 (m, 1H), 1.72–1.92 (m, 4H), 1.56–1.64 (m, 1H), 1.17–1.28 ppm
(m, 1H); MS (ESI): m/z (%) 525 (100) [M+H]+.
(1S,5R)-3-{4-[4-methyl-5-(1,3,5-trimethyl-1H-pyrazol-4-yl)-4H-
1,2,4-triazol-3-yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hexane hydrochloride (22): 1H NMR (400 MHz,
CD3OD): d=7.67 (d, J=8.3 Hz, 2H), 7.52 (d, J=8.3 Hz, 2H), 4.04–
4.25 (m, 1H), 3.82 (s, 3H), 3.80–3.91 (m, 1H), 3.64–3.79 (m, 2H),
3.57 (s, 3H), 3.39 (t, J=7.3 Hz, 2H), 2.99 (t, J=6.2 Hz, 2H), 2.32–
2.38 (m, 1H), 2.26 (s, 3H), 2.17 (s, 3H), 1.92–2.04 (m, 4H), 1.42–1.53
(m, 1H), 1.34–1.44 ppm (m, 1H); MS (ESI): m/z (%) 473 (100)
[M+H]+.
(1S,5R)-3-{4-[5-(2-fluorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]bu-
tyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane hy-
drochloride (30): MS (ESI): m/z (%) 459 (100) [M+H]+.
(1S,5R)-3-{4-[5-(3-fluorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]bu-
tyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane hy-
drochloride (31): 1H NMR (500 MHz, [D6]DMSO): d=10.40 (brs,
1H), 7.73 (d, J=8.1 Hz, 2H), 7.52–7.59 (m, 2H), 7.48–7.68 (m, 3H),
7.42 (td, J=8.4 Hz, J=1.8 Hz, 1H), 3.97–4.22 (m, 1H), 3.64 (s, 3H),
3.57–3.83 (m, 2H), 3.46–3.59 (m, 1H), 3.20–3.34 (m, 2H), 2.85 (t,
2H), 2.24–2.40 (m, 1H), 1.74–2.00 (m, 4H), 1.65–1.76 (m, 1H), 1.16–
1.31 ppm (m, 1H); MS (ESI): m/z (%) 459 (100) [M+H]+.
(1S,5R)-3-{4-[5-(2-chlorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]-
butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (23): 1H NMR (300 MHz, [D6]DMSO): d=10.26 (brs,
1H), 7.64–7.76 (m, 3H), 7.57–7.65 (m, 1H), 7.42–7.54 (m, 4H), 3.94–
4.14 (m, 1H), 3.68–3.78 (m, 1H), 3.58–3.67 (m, 1H), 3.46–3.56 (m,
(1S,5R)-3-{4-[5-(4-fluorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]bu-
tyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane hy-
ChemMedChem 2010, 5, 705 – 715
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemmedchem.org
713

F. Micheli et al.
MED
drochloride (32): 1H NMR (300 MHz, [D6]DMSO): d=10.50 (brs,
1H), 7.64–7.78 (m, 4H), 7.49 (d, J=7.8 Hz, 2H), 7.40 (t, J=9.0 Hz,
2H), 3.95–4.10 (m, 1H), 3.65–3.81 (m, 1H), 3.59 (s, 3H), 3.57–3.67
(m, 1H), 3.46–3.57 (m, 1H), 3.19–3.28 (m, 2H), 2.80 (t, J=7.3 Hz,
2H), 2.25–2.34 (m, 1H), 1.74–1.91 (m, 4H), 1.68–1.75 (m, 1H), 1.15–
1.23 ppm (m, 1H); MS (ESI): m/z (%) 459 (100) [M+H]+.
2.95–3.05 (m, 2H), 2.28–2.42 (m, 1H), 1.85–2.07 (m, 4H), 1.48–1.59
(m, 10H), 1.28–1.42 ppm (m, 1H); MS (ESI): m/z (%) 421 (100)
[M+H]+.
(1S,5R)-3-[5-(4-methyl-5-phenyl-4H-1,2,4-triazol-3-yl)pentyl]-1-[4-
(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochlo-
ride (40): 1H NMR (500 MHz, CD3OD): d=7.69 (m, 4H), 7.56 (m,
3H), 7.49 (d, J=8.3 Hz, 2H), 4.03 (d, J=10.8 Hz, 1H), 3.70 (d, J=
11.2 Hz, 1H), 3.61 (m, 1H), 3.61 (s, 3H), 3.49 (m, 1H), 3.17 (m, 2H),
2.82 (t, J=7.3 Hz, 2H), 2.28 (m, 1H), 1.77 (m, 6H), 1.44 (m, 1H),
1.18 ppm (m, 1H); 13C NMR (150 MHz, [D6]DMSO): d=155.2, 153.8,
144.4, 129.3, 129.0, 128.5, 128.2, 126.9, 126.0, 125.0, 124.4, 56.3,
54.7, 30.7, 30.0, 25.3, 25.2, 24.4, 23.6, 23.4, 18.2 ppm; MS (ESI): m/z
(%) 455 (100) [M+H]+.
(1S,5R)-3-[4-methyl-5-(4-{-1-[4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hex-3-yl}butyl)-4H-1,2,4-triazol-3-yl]benzonitrile
hydrochloride (33): 1H NMR (400 MHz, CDCl3): d=7.90–7.99 (m,
2H), 7.81 (d, J=7.8 Hz, 1H), 7.67 (t, J=7.8 Hz, 1H), 7.54 (d, J=
8.2 Hz, 2H), 7.23 (d, J=8.2 Hz, 2H), 3.65 (s, 3H), 3.35–3.47 (m, 1H),
3.09–3.23 (m, 1H), 2.77–2.92 (m, 2H), 2.47–2.69 (m, 4H), 1.47–
2.03 ppm (m, 7H); MS (ESI): m/z (%) 466 (100) [M+H]+.
(1S,5R)-4-[4-methyl-5-(4-{-1-[4-(trifluoromethyl)phenyl]-3-
azabicyclo[3.1.0]hex-3-yl}butyl)-4H-1,2,4-triazol-3-yl]benzonitrile
hydrochloride (34): 1H NMR (400 MHz, CD3OD): d=7.86 (d, J=
8.3 Hz, 2H), 7.79 (d, J=8.3 Hz, 2H), 7.57 (d, J=8.3 Hz, 2H), 7.41 (d,
J=8.3 Hz, 2H), 3.96–4.18 (m, 1H), 3.70–3.84 (m, 1H), 3.61 (s, 3H),
3.49–3.70 (m, 2H), 3.27 (t, J=7.6 Hz, 2H), 2.88 (t, J=6.6 Hz, 2H),
2.20–2.30 (m, 1H), 1.76–1.96 (m, 4H), 1.23–1.42 ppm (m, 2H); MS
(ESI): m/z (%) 466 (100) [M+H]+.
(1S,5R)-3-{5-[4-methyl-5-(5-methyl-2-pyrazinyl)-4H-1,2,4-triazol-
3-yl]pentyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
1
[3.1.0]hexane hydrochloride (41): H NMR (300 MHz, CD3OD): d=
9.14 (m, 1H), 8.66 (m, 1H), 7.65 (d, J=8.3 Hz, 2H), 7.50 (d, J=
8.3 Hz, 2H), 4.17 (d, J=10.6 Hz, 1H), 3.99 (m, 3H), 3.85 (d, J=
10.8 Hz, 1H), 3.64 (m, 2H), 3.30 (m, 2H), 2.94 (t, J=7.3 Hz, 2H), 2.64
(m, 3H), 2.34 (brs, 1H), 1.88 (m, 4H), 1.55 (m, 2H), 1.42 (m, 1H),
1.35 ppm (m, 1H); MS (ESI): m/z (%) 455 (100) [M+H]+.
(1S,5R)-3-{4-[5-(2,4-difluorophenyl)-4-methyl-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (35): 1H NMR (400 MHz, [D6]DMSO): d=10.37 (brs,
1H), 7.71 (d, J=8.3 Hz, 2H), 7.61–7.69 (m, 1H), 7.54 (dd, J=
10.2 Hz, 2.4 Hz, 1H), 7.49 (d, J=8.3 Hz, 2H), 7.30 (dt, J=8.3 Hz,
2.4 Hz, 1H), 4.04 (d, J=10.1 Hz, 1H), 3.74 (d, J=10.0 Hz, 1H), 3.57–
3.67 (m, 1H), 3.46–3.58 (m, 1H), 3.44 (s, 3H), 3.15–3.32 (m, 2H),
2.81 (t, J=6.8 Hz, 2H), 2.26–2.34 (m, 1H), 1.75–1.97 (m, 4H), 1.65–
1.71 (m, 1H), 1.16–1.27 ppm (m, 1H); MS (ESI): m/z (%) 477 (100)
[M+H]+.
(1S,5R)-3-{5-[4-methyl-5-(4-methyl-1,3-oxazol-5-yl)-4H-1,2,4-tria-
zol-3-yl]pentyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
1
[3.1.0]hexane hydrochloride (42): H NMR (400 MHz, CD3OD): d=
8.35 (s, 1H), 7.66 (d, J=8.2 Hz, 2H), 7.50 (d, J=8.2 Hz, 2H), 3.83 (d,
J=10.8 Hz, 1H), 3.75 (s, 3H), 3.54–3.72 (m, 3H), 3.22–3.32 (m, 2H),
2.91 (t, J=7.5 Hz, 2H), 2.43 (s, 3H), 2.25–2.37 (m, 1H), 1.76–1.97 (m,
4H), 1.48–1.62 (m, 2H), 1.35–1.47 (m, 1H), 1.11–1.26 ppm (m, 1H);
MS (ESI): m/z (%) 460 (100) [M+H]+.
(1S,5R)-3-{5-[5-(2-chlorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]-
pentyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (43): 1H NMR (400 MHz, [D6]DMSO): d=7.63–7.71
(m, 4H), 7.54–7.59 (m, 2H), 7.47–7.53 (m, 2H), 4.07–4.22 (m, 1H),
3.78–3.95 (m, 1H), 3.68–3.76 (m, 1H), 3.61–3.67 (m, 1H), 3.51 (s,
3H), 3.25–3.37 (m, 2H), 2.97 (t, J=7.3 Hz, 2H), 2.36 (brs, 1H), 1.91–
2.01 (m, 2H), 1.79–1.91 (m, 2H), 1.50–1.63 (m, 2H), 1.39–1.48 (m,
1H), 1.33–1.41 ppm (m, 1H); MS (ESI): m/z (%) 489 (100) [M+H]+.
(1S,5R)-3-{4-[5-(3,5-difluorophenyl)-4-methyl-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (36): 1H NMR (400 MHz, [D6]DMSO): d=10.32 (brs,
1H), 7.70 (d, J=8.3 Hz, 2H), 7.52–7.42 (m, 5H), 4.05 (d, J=10.3 Hz,
1H), 3.72 (d, J=9.2 Hz, 1H), 3.57–3.67 (m, 1H), 3.63 (s, 3H), 3.46–
3.55 (m, 1H), 3.15–3.32 (m, 2H), 2.81 (t, J=6.8 Hz, 2H), 2.26–2.34
(m, 1H), 1.75–1.90 (m, 4H), 1.65–1.71 (m, 1H), 1.16–1.27 ppm (m,
1H); MS (ESI): m/z (%) 477 (100) [M+H]+.
(1S,5R)-3-{5-[5-(4-chlorophenyl)-4-methyl-4H-1,2,4-triazol-3-yl]-
pentyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (44): 1H NMR (400 MHz, CD3OD): d=7.75 (d, J=
8.3 Hz, 2H), 7.67 (d, J=8.3 Hz, 4H), 7.51 (d, J=8.3 Hz, 2H), 4.16 (d,
J=11.0 Hz, 1H), 3.88 (d, J=10.6 Hz, 1H), 3.76 (s, 3H), 3.60–3.73 (m,
2H), 3.27–3.42 (m, 2H), 3.00 (t, J=6.8 Hz, 2H), 2.28–2.40 (m, 1H),
1.82–2.02 (m, 4H), 1.56–1.66 (m, 2H), 1.47–1.55 (m, 1H), 1.31–
1.40 ppm (m, 1H); MS (ESI): m/z (%) 489 (100) [M+H]+.
(1S,5R)-3-{4-[5-(3,4-difluorophenyl)-4-methyl-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (37): 1H NMR (500 MHz, [D6]DMSO): d=10.59 (brs,
1H), 7.81 (m, 1H), 7.71 (d, J=7.8 Hz, 2H), 7.65 (m, 1H), 7.57 (m,
1H), 7.50 (d, J=7.8 Hz, 2H), 4.06 (d, J=9.8 Hz, 1H), 3.74 (d, J=
10.4 Hz, 1H), 3.62 (m, 3H), 3.43 (m, 2H), 3.25 (m, 2H), 2.84 (m, 2H),
2.30 (m, 1H), 1.84 (m, 5H), 1.19 ppm (m, 1H); MS (ESI): m/z (%) 477
(100) [M+H]+.
(1S,5R)-3-(5-{4-methyl-5-[3-(methyloxy)phenyl]-4H-1,2,4-triazol-
3-yl}pentyl)-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
(1S,5R)-3-{4-[5-(2,4-dichlorophenyl)-4-methyl-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (38): 1H NMR (300 MHz, [D6]DMSO): d=10.4 (brs,
1H), 7.9 (d, J=2 Hz, 1H), 7.7 (d, J=8.0 Hz, 2H), 7.65 (d, J=8.0 Hz,
1H), 7.6 (d, J=8.0 Hz, 1H), 7.5 (d, J=8.0 Hz, 2H), 4.05 (m, 1H),
3.67–3.79 (m, 1H), 3.59–3.68 (m, 1H), 3.44–3.56 (m, 1H), 3.17–3.30
(m, 2H), 2.82 (m, 2H), 2.2–2.3 (m, 1H), 1.7–1.9 (m, 4H), 1.7 (m, 1H),
1.15–1.2 ppm (m, 1H); MS (ESI): m/z (%) 509 (100) [M+H]+.
[3.1.0]hexane hydrochloride (45): 1H NMR (400 MHz, [D6]DMSO):
d=10.40 (brs, 1H), 7.69 (d, J=8.2 Hz, 2H), 7.46–7.53 (m, 3H), 7.22
(d, J=7.6 Hz, 1H), 7.19 (d, J=2.2 Hz, 1H), 7.10 (dd, J=7.6 Hz,
2.2 Hz, 1H), 4.08 (d, J=11.0 Hz, 1H), 3.82 (s, 3H), 3.67–3.78 (m, 1H),
3.59–3.67 (m, 1H), 3.59 (s, 3H), 3.45–3.56 (m, 1H), 3.11–3.25 (m,
2H), 2.79 (t, J=7.2 Hz, 2H), 2.20–2.33 (m, 1H), 1.74–1.85 (m, 4H),
1.38–1.51 (m, 2H), 1.28–1.37 (m, 1H), 1.16–1.24 ppm (m, 1H); MS
(ESI): m/z (%) 485 (100) [M+H]+.
(1S,5R)-3-{4-[5-(1,1-dimethylethyl)-4-methyl-4H-1,2,4-triazol-3-
yl]butyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo[3.1.0]hexane
hydrochloride (39): 1H NMR (400 MHz, CD3OD): d=7.67 (d, J=
8.3 Hz, 2H), 7.51 (d, J=8.3 Hz, 2H), 4.00–4.23 (m, 1H), 3.91 (s, 3H),
3.91 (s, 3H), 3.91 (s, 3H), 3.54–3.80 (m, 2H), 3.34–3.42 (m, 2H),
(1S,5R)-3-{5-[5-(2,4-difluorophenyl)-4-methyl-4H-1,2,4-triazol-3-
yl]pentyl}-1-[4-(trifluoromethyl)phenyl]-3-azabicyclo-
[3.1.0]hexane hydrochloride (46): 1H NMR (400 MHz, [D6]DMSO):
d=10.18 (brs, 1H), 7.70 (d, J=8.2 Hz, 2H), 7.60–7.67 (m, 1H), 7.50–
7.57 (m, 1H), 7.48 (d, J=8.2 Hz, 2H), 7.30 (td, J=8.5 Hz, 2.2 Hz,
714
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ChemMedChem 2010, 5, 705 – 715

Triazolyl Azabicyclo[3.1.0]hexanes
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3.55 (m, 1H), 3.43 (s, 3H), 3.12–3.27 (m, 2H), 2.79 (t, J=6.8 Hz, 2H),
2.25–2.33 (m, 1H), 1.70–1.83 (m, 4H), 1.59–1.66 (m, 1H), 1.44 (m,
2H), 1.17–1.27 ppm (m, 1H); MS (ESI): m/z (%) 491 (100) [M+H]+.
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from the key GYG motif (GFG in hERG) and the key hinge glycine
residue in S6. The alignment of the S5 helices of hERG and KcsA,
however, was not clear. This was finally based on the observation
of a highly conserved glutamate at the extracellular side of S5
which is found in most potassium channels. A published[25] NMR
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the CHARMm program,[26] with an initial 500 steps of steepest de-
scent, followed by 5000 steps of ABNR, and a constant dielectric of
5. Helical hydrogen bonding distance constraints were used to
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to generate the alignment. Use was made of the S5–SS1 loop
model constructed for the closed-state structure, and the same
CHARMm conditions were used for final refinement.
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Acknowledgements
We thank Dr. F. Damiani, Dr. D. Hamprecht, Dr. E. Fazzolari, Dr.
C. Mazzoni, Dr. S. Fontana, Dr. F. Blaney, and Dr. S. Provera for
their support in the development of this work. We also thank Dr.
D. Donati and Dr. J. Hagan for fruitful discussions during the
setup of this work.
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[21] http://www.wavefun.com (accessed February 22, 2010).
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,
Keywords: azabicyclo[3.1.0]hexanes
antagonists · hERG channel · receptors
·
dopamine
D3
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islation and with company policy on the care and use of animals and
with related codes of practice.
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Received: January 19, 2010
Revised: February 11, 2010
Published online on March 15, 2010
ChemMedChem 2010, 5, 705 – 715
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemmedchem.org
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