Selective antagonists of mouse trace amine-associated receptor 1 (mTAAR1): Discovery of EPPTB (RO5212773)

Article abstract of DOI:10.1016/j.bmcl.2010.12.075

High throughput screening of the Roche compound library identified benzanilides such as 1 and 2 as antagonists of TAAR1. Optimisation of this hit series led to the first selective TAAR1 antagonist (N-(3-Ethoxy-phenyl)-4- pyrrolidin-1-yl-3-trifluoromethyl-

Full text of DOI:10.1016/j.bmcl.2010.12.075

Bioorganic & Medicinal Chemistry Letters 21 (2011) 1227–1231
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Selective antagonists of mouse trace amine-associated receptor 1 (mTAAR1):
Discovery of EPPTB (RO5212773)
⇑
Henri Stalder , Marius C. Hoener, Roger D. Norcross
F. Hoffmann-La Roche Ltd, Pharma Research, CH-4070 Basel, Switzerland
a r t i c l e i n f o
a b s t r a c t
Article history:
High throughput screening of the Roche compound library identified benzanilides such as 1 and 2 as
antagonists of TAAR1. Optimisation of this hit series led to the first selective TAAR1 antagonist
(N-(3-Ethoxy-phenyl)-4-pyrrolidin-1-yl-3-trifluoromethyl-benzamide EPPTB (RO5212773, 9f) having
IC50 of 28 nM at mouse TAAR1.
Received 12 November 2010
Revised 14 December 2010
Accepted 15 December 2010
Available online 21 December 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
TAAR1
Antagonists
Inverse agonists
EPPTB
RO5212773
Benzanilides
Trace amine-associated receptor 1 (TAAR1) is a G protein-
coupled receptor (GPCR) which is activated by endogenous metab-
olites of amino acids such as p-tyramine, b-phenethylamine,
octopamine and tryptamine,1,2 that are found in low concentrations
in the brain.3 TAAR1 is considered a promising drug target for the
treatment of psychiatric and neurodegenerative disorders.4–6 The
availability of selective agonists and antagonists of TAAR1 is key
for obtaining critical information with regard to the therapeutic
potential of this target.7 Here we report the discovery and the iden-
tification of EPPTB, that was recently described to be a competitive
TAAR1 antagonist and inverse agonist.8
active compounds; all were antagonists at mTAAR1 (IC50 <16
12 compounds had IC50 <1 M, all compounds had EC50 >20
l
l
M,
M,
l
data not shown). Furthermore, selected primary hits were also
tested for functional activity at human TAAR1 (hTAAR1) resulting
in comparable values to human/rat chimeric TAAR1. The profiles
of two representative benzanilides are shown in Figure 1. The val-
ues reported are the average of at least two independent experi-
ments and typically duplicate values are within
a twofold
margin.12 Compound 1 was one of the most active hits found in
the HTS.
The binding assay data for 1 and 2 reveal high affinity for
mTAAR1 (Ki 2–4 nM) resulting in ligand efficiency (LE) around 0.4
A high throughput screening (HTS) of the Roche compound
library (ꢀ788’000 compounds at 10
l
M) was performed using a
but only weak affinity at rat TAAR1 (rTAAR1) (Ki 1.4
detectable affinity for hTAAR1 (Ki >20 M). These results are re-
flected in the functional assay data: at mTAAR1 1 had IC50
0.006 M (28% residual stimulation by endogenous agonist b-PEA,
partial agonist) and 2 had IC50 0.060 M (full antagonist), whereas
at hTAAR1 1 had IC50 >10 M and 2 had IC50 3.79 M. Regardless
of the chemical series, we observed significant species differences
in binding affinity at TAAR1 for all the HTS hits. Whereas many com-
pounds were potent at mTAAR1, the majority of compounds were
inactive at hTAAR1 and only weakly active at rTAAR1. Therefore
the focus of chemical optimisation narrowed to the search for a tool
compound suitable for mechanistic in vitro pharmacology experi-
ments and in vivo behavioural studies in mice.
lM) and no
functional cAMP assay employing a chimeric human/rat TAAR1
receptor.9 The cAMP assay was run in both antagonist (IC50) and
agonist (EC50) mode. The resulting primary hit set was clustered10
according to substructure similarity and based on this analysis a
hit expansion was performed. The extended primary hit set was
then tested at mouse TAAR1 (mTAAR1) in antagonist and agonist
dose–response mode. The switch from the human/rat chimeric to
the mouse TAAR1 for dose–response determination was due to a
licensing issue and considered as reasonable due to the good
homology between human and mouse TAAR1.11 With 25 represen-
tatives, benzanilides were the most prominent chemical class
found and represented not only the largest set but also the most
l
l
l
l
l
All compounds from the HTS hit series having high functional
activity at mTAAR1 had high lipophilicity (c log P >4; log D >3),
poor aqueous solubility (<1
in human and mouse microsomes.
l
g/ml at pH 6.5), and high clearance
⇑
Corresponding author. Tel.: +41 61 688 40 16; fax: +41 61 6886459.
E-mail address: henri.stalder@roche.com (H. Stalder).
A
medicinal chemistry
0960-894X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2010.12.075

1228
H. Stalder et al. / Bioorg. Med. Chem. Lett. 21 (2011) 1227–1231
O
O
N+
F
O
N
S
N
O
H
H
O
N
N
O
O
O
1 [rac/meso] (RO4467280-000)
2 (RO4534926-000)
Functional assay i)
Functional assayi)
Binding
Binding
Ki > 20
hTAAR1 :
mTAAR1:
rTAAR1 :
Ki > 20
µM
IC50 3.79 µM (0%)
IC50 0.060 µM (0%)
IC50 --- µM
µM
0.002 µM; LE 0.44
--- µM
IC50 >10
µM
Ki
Ki
0.004 µM; LE 0.40
1.39 µM
Ki
Ki
IC50
IC50
0.006 µM (28%)
--- µM
Microsomes
Microsomes
Clearance ii)
h 154
Phys-chem. prop.
Phys-chem. prop.
MW:
420.5
62.8
4.6
Clearance ii)
MW:
369.4
72.7
4.3
PSA:
h
538
PSA:
clogP :
m 1705
clogP :
m 396
solubility: <1µg/ml iii)
solubility: <1µg/ml iii)
Figure 1. Profile of benzanilides 1 and 2 found in HTS. hTAAR1 = human TAAR1, mTAAR1 = mouse TAAR1, rTAAR1 = rat TAAR1, LE = ligand efficiency; (i) antagonistic efficacy:
reversal of effect of endogenous agonist b-PEA (in vitro cAMP functional assay; 100% efficacy = 0% min% stim.); (ii) intrinsic clearance in vitro in mouse (m) and human
(h) liver microsomes, lg/min/mg protein; (iii) aqueous solubility at pH 6.5.
optimisation programme was initiated focusing on the improve-
ment of physicochemical properties and metabolic stability.
Our synthetic approach allowed a rapid modification of the exit
vectors around the central benzanilide core (Scheme 1). The
benzanilides or nicotinanilides were obtained in one step from
the benzoic or nicotinic acid derivatives by condensation with ani-
lines (Scheme 1, step a). In cases where R2 was an electron-with-
drawing group (CF3 or NO2), halogens in para position of the
benzoyl moiety could be substituted with amines leading to com-
pounds 2, 6a–6k and 9b. meta-Acetyl compound 8e was prepared
by Heck type reaction of the corresponding meta-bromo compound
8b with vinyl butyl ether followed by hydrolysis of the inter-
mediate vinyl ether. Compounds 10a and 10b were obtained by
substitution with amines of the 6-chloro substituent in 6-chloro-
N-(3-methoxy-phenyl)-5-trifluoromethyl-nicotinamide 11.
meta,meta’-disubstitution led to compounds with weaker affinity
(mTAAR1 Ki ꢁ100 nM; data not shown), whereas monosubstitu-
tion in the meta position afforded compounds with high affinity
with the exception of phenyl, CF3 and MeSO2: these displayed a
binding affinity at mTAAR1 of Ki >200 nM. Small substituents are
preferred at the meta position, especially methoxy (3) and chloro
(4) residues (Table 1). Aniline derivative 5 proved to be equipotent
with the chloro compound 4. However, benzanilides derived from
aniline showed in most cases a clearly lower binding affinity than
the corresponding meta-chloro or meta-methoxy aniline deriva-
tives (data not shown).
The 3-methoxy-aniline motif was selected as optimal at this
stage and structural modification was then directed towards the
benzoyl residue. Starting from 2, a first effort modifying or
replacing the amino residue was undertaken (Tables 2 and 3).
Replacement of the 4-methyl-piperidin-1yl residue in 2 by an ami-
The structure–activity relationship (SAR) for substituents on the
aniline moiety (e.g., MeO, F, Cl, Me, Et, phenyl, CF3, acetyl, MeSO2)
was examined first. Monosubstitution in ortho or para positions, or
no group led to significant loss of affinity (6a: Ki 1.92
lM) but
activity could be recovered by mono N-alkylation (6b–6e). The best
O
R2
OH
+
H2N
R3
R1
X
R3 = H, Cl, MeO, RO (as per Table 5)
X = CH, N
a)
O
O
O
F
R1 = F, R2 = NO2
X = CH
R1 = F, R2 = CF3
X = CH
O
F
N+
N
R3
R2
R1
N
O
O
R4
H
N
H
R3
H
F
b)
c)
N
R5
N
X
9b
2, 6a-6k
3-5, 7a-7e, 8a-8d, 8f-8k, 9a, 9c-9n, 11
8b 11
O
R1 = Cl, R2 = CF3
R3 = OMe, X = N
F
R1 = F, R2 = Br
O
O
F
R3 = OMe, X = CH
N
O
F
N
O
H
R4
d)
e)
H
N
N
F
R5
8e
10a, 10b
Scheme 1. Synthesis of benz- and nicotin-anilides 2–11. Reagents and conditions: (a) EDC, DMAP, CH2Cl2, rt, 18 h, 16–99%; (b) HNR4R5, DMF, rt, 2.5 h or THF, 60 °C, 70 h,
43–99%; (c) pyrrolidine, DMF, rt, 20 h, 98%; (d) (i) H2C@CH–O–nBu, Pd(OAc)2, dppp, iPr2NH, DMSO/[bmim][BF4] 10:1, 170 °C (microwave), 15 min, 31%; (ii) 5% aq HCl, rt,
30 min 65%; (e) HNR4R5, NMP, 10a:150 °C (microwave), 15 min, 53%; 10b: 250 °C (microwave), 15 min, 71%.

H. Stalder et al. / Bioorg. Med. Chem. Lett. 21 (2011) 1227–1231
1229
Table 1
Table 3
Binding affinity at mTAAR1 for 3-substituted anilines
In vitro binding affinity and functional activity at mTAAR1 for non-basic benzoyl
derivatives
O
O
O
N+
Cl
N
R
H
R
Cl
H
N
O
3 - 5
O
Entry
R
mKi (lM)
7a - 7e
3
4
5
MeO
Cl
H
0.025
0.060
0.054
Entry
R
mKi ( M)
l
mIC50
(
l
M)
min % stim.a
0
7a
7b
7c
7d
7e
H
F
Cl
Br
0.189
0.090
0.037
0.021
0.262
0.665
nt
0.012
0.043
nt
0
0
Table 2
Pyrazol-1-yl
In vitro binding affinity and functional activity at mTAAR1 for 4-amino-benzoyl
derivatives
a
Residual stimulation by endogenous agonist b-PEA at maximum concentration
of test compound; Antagonistic efficacy: reversal of effect of endogenous agonist b-
PEA (in vitro cAMP functional assay; 100% efficacy = 0% min % stim.).
O
O
R1
N
N+
R2
H
N
often replaced by a strong electron-withdrawing group like CN,
SO2Me or SO2NH2.13,14 In our series substitution of the nitro residue
with these functional groups led to compounds with inferior bind-
ing affinity for mTAAR1 (Table 4). While binding affinity of the ni-
trile derivative 8f was only weakly attenuated, the methylsulfonyl
(8k) and sulfonylamide (8j) derivatives proved to be substantially
weaker. As demonstrated with sulfonamide 8h, introduction of a
large and lipophilic substituent led to recovery of binding affinity
compared to the less lipophilic 8j. Replacement of the nitro group
in 7b with a lipophilic non-polarizing moiety like Me (8i) led to
significant loss of activity, whereas replacement with polarizing
substituents like acetyl (8e) or polarizing and lipophilic substituents
like fluoro (8g) or trifluoromethoxy (8d) resulted in only a slight
drop in activity. Substitution of the nitro residue with chloro (8c)
led to an equipotent compound. Replacing chloro with a more
lipophilic substituent such as bromo (8b) or trifluoromethyl (8a)
improved the binding affinity at mTAAR1 up to threefold. Only com-
pound 7a and 8a were tested in the functional assay: at mTAAR1 7a
O
O
2, 6a - 6k
Entry
R1
R2
mKi (
lM)
mIC50
(
lM)
min% stim.a
0
2
–(CH2)2–CH(Me)–(CH2)2–
0.002
1.92
0.060
nt
6a
6b
6c
6d
6e
6f
6g
6h
6i
H
H
H
H
H
H
H
Et
nPr
iPr
Benzyl
Phenyl
0.024
0.004
0.012
0.005
0.029
0.029
0.013
0.012
0.103
0.164
0.075
0.013
0.142
0.014
0.175
0.200
0.017
0.019
0.079
nt
23
14
0
3
0
9
0
0
0
–(CH2)3–
–(CH2)4–
–(CH2)5–
–(CH2)2–O–(CH2)2–
–(CH2)2–NMe–(CH2)2–
6j
6k
a
Residual stimulation by endogenous agonist b-PEA at maximum concentration
of test compound; Antagonistic efficacy: reversal of effect of endogenous agonist b-
PEA (in vitro cAMP functional assay; 100% efficacy = 0% min % stim.).
Table 4
binding affinity and functional activity was observed for nPr (6c: Ki
In vitro binding affinity at mTAAR1 for benzanilides with replacements for meta-nitro
residue
0.004
0.014
l
l
M, IC50 0.013
lM) and for benzyl (6e: Ki 0.005 lM, IC50
M) substituents, both displaying similar affinity and func-
R
tional activity at mTAAR1. For the phenyl derivative (6f) a drop
R'
in affinity and activity was observed. Cyclic secondary amine
H
N
O
substituents (6g–6k) displayed
(Ki 0.012–0.164 M), with the pyrrolidine (6h) or piperidine (6i)
derivatives being optimal in terms of functional activity (IC50
0.017–0.019 M). However, in terms of binding affinity, 2 still
remained the most potent compound in our hands, although in
the functional assay, 2 (IC50 0.060 M) was inferior to the pyrroli-
a high affinity for mTAAR1
l
O
7a, 7b, 8a-8k
l
Entry
R0
R
Ki (l
M)
c log P
l
7a
7b
8a
8b
8c
8d
8e
8f
H
F
F
F
F
F
F
F
F
NO2
NO2
CF3
Br
0.189
0.090
0.030
0.056
0.100
0.138
0.139
0.149
0.229
2.8
2.7
4.0
3.9
3.7
4.0
2.3
2.7
3.1
dine and piperidine derivatives 6h and 6i, respectively. All three
compounds are full antagonists of mTAAR1.
Omitting the 4-amino residue furnished 7a (Table 3), a signifi-
cantly less active compound with Ki 0.189 lM and IC50 0.665 lM.
The amino moiety may be replaced with halogen substituents,
whereby increasing size leads to increasing affinity: from Ki
Cl
CF3O
COMe
CN
0.090
7d. In the functional assay at mTAAR1, the chloro compound 7c (Ki
0.037 M) displayed an IC50 of 0.012 M. Substitution of bromine
with a larger and non-basic substituent like pyrazole-1-yl in 7e
resulted in a strong drop of binding affinity to Ki 0.262 M.
lM for fluoro derivative 7b to 0.021 lM for bromo compound
8g
F
O
l
l
S
*
N
8h
F
0.694
3.6
O
8i
8j
8k
F
F
H
Me
SO2NH2
SO2Me
1.58
7.43
6.00
3.5
1.5
1.6
l
Based on 7a and 7b, replacement options for the nitro group
were explored next. The nitro group, a potential toxicophore, is

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H. Stalder et al. / Bioorg. Med. Chem. Lett. 21 (2011) 1227–1231
Table 5
4.6) displayed the highest binding affinity with Ki 0.009 lM. Sub-
stitution of the methoxy group by a fluoroalkoxy, that is, 9c, 9d,
2nd Optimisation of aniline part: in vitro binding affinity at mTAAR1
or 9g, or by a phenoxy residue, that is, 9j, provided compounds
with Ki in the range 0.012 lM (c log P 4.7) to 0.082 lM (c log P
6.4), whereby a decrease of binding affinity with increasing lipo-
philicity was again observed. Substitution of the methoxy group
by other alkoxy substituents afforded the best results. Compound
9i bearing a 3-isopropoxy residue was equipotent with methoxy
O
F
F
3
4
1
R
N
F
H
N
9a - 9n
c log P
derivative 9b, and the highest affinity of all with Ki 0.0009 lM
Entry
R
Ki (l
M)
IC50
(
l
M)
min % stima
was shown by 3-ethoxy compound 9f (c log P 4.8). In the functional
assay at mTAAR1 all tested compounds proved to be full
antagonists.
Attempts to reduce the lipophilicity of 9b by replacing the
benzoyl part by a nicotinoyl moiety led to a compound having an
excellent binding affinity of Ki 0.002 (Table 6, 10a). Note that the
9a
9b
9c
9d
9e
9f
9g
9h
9i
9j
9k
9l
9m
9n
Me
0.016
0.003
0.012
0.101
0.021
0.0009
0.039
0.065
0.004
0.082
0.026
0.009
0.020
0.046
4.8
4.3
4.7
5.4
5.4
4.8
6.2
5.8
5.1
6.4
4.0
4.6
5.1
5.3
0.070
0.067
0.187
nt
0.470
0.028
0.364
nt
0.027
nt
0.120
0.020
0.245
0.568
0
0
0
OMe
OCHF2
OCF3
Et
OEt
OCF2CHF2
iPr
OiPr
OPh
Ac
0
ꢂ12
0
more lipophilic analogue 10b with IC50 0.22
(c log P 4.7) had significantly lower functional activity compared
to the less lipophilic 10a with IC50 0.006 M (c log P 3.7).
lM and log D >4
0
l
0
0
0
0
The most promising compounds arising from our SAR explora-
tion work, compounds 2, 6j, 9b, 9f, 10a and 10b, were tested for
their in vitro metabolic stability in mouse microsomes (Table 6).
Benzanilide 2 and the nicotinoyl derivatives 10a and 10b unfortu-
nately proved to be rapidly metabolized during the microsomal
incubation. The 4-(1-morpholinyl)-3-nitro-benzoyl derivative 6j
having low lipophilicity (log D 2.7) displayed a medium clearance
F
Cl
Br
a
Residual stimulation by endogenous agonist b-PEA at maximum concentration
of test compound; Antagonistic efficacy: reversal of effect of endogenous agonist b-
PEA (in vitro cAMP functional assay; 100% efficacy = 0% min % stim.).
had IC50 0.665
antagonist).
lM (full antagonist) and 8a had IC50 0.028
lM (full
of 18
able IC50 0.079
l
g/min/mg protein in mouse microsomes and had an accept-
lM but unfortunately proved to be unstable in
Based on the results compiled in Table 4, the trifluoromethyl
group (as in 8a) was chosen as a suitable bioisosteric replacement
of the nitro group. Combined with the preferred pyrrolidinyl resi-
due (cf. Table 2) we obtained 9b which displayed Ki 0.003 lM at
mTAAR1 (Table 5).
With the 4-pyrrolidinyl-3-trifluoromethyl benzoyl residue as
the optimized left hand part, a second optimization of the 3-substi-
tuent on the aniline moiety was undertaken (Table 5). Replacing
the methoxy group in 9b by an alkyl moiety, that is, 9a, 9e or 9h,
or by a halogen, that is, 9l–9n, led to loss of binding affinity. Among
these compounds the least lipophilic fluoro compound 9l (c log P
mouse plasma. We therefore focused our attention on compound
9f having a meta-ethoxy residue on the aniline part which, com-
pared to methoxy analogue 9b, not only showed a higher binding
affinity and functional activity but also a lower microsomal clear-
ance. Compound 9f was therefore selected for profiling in single
dose in vivo pharmacokinetic (PK) experiments in mice comparing
different routes of parenteral administration (Fig. 2).15
In the event, 9f displayed a high clearance after iv administra-
tion to mice but achieved good bioavailability (74%) after ip appli-
cation, reaching a maximum plasma concentration of 590 ng/ml
following a dose of 5 mg/kg ip (Fig. 2). With a measured brain/
Table 6
Microsomal clearance and lipophilicity of key compounds, compared to in vitro binding affinity and functional activity at mTAAR1
O
R1
N
O
R3
H
R2
X
2, 6j, 9b, 9f, 10a, 10b
Ki ( M) IC50
Entry
X
R1
R2
R3
l
(lM)
min % stim.a
0
Clearanceb
396
log D
>3
c log P
*
N
2
CH
NO2
Me
0.002
0.103
0.060
0.079
4.3
*
N
6j
CH
NO2
Me
0
18
2.7
2.4
O
*
*
*
N
9b
9f
CH
CH
N
CF3
CF3
CF3
Me
Et
0.003
0.0009
0.002
0.067
0.028
0.006
0
ꢂ12
0
341
109
321
4.3
4.8
3.7
N
N
10a
Me
*
N
10b
N
CF3
Me
0.002
0.220
0
107
>4
4.7
a
Residual stimulation by endogenous agonist b-PEA at maximum concentration of test compound; Antagonistic efficacy: reversal of effect of endogenous agonist b-PEA
(in vitro cAMP functional assay; 100% efficacy = 0% min % stim.).
b
Intrinsic clearance in mouse liver microsomes, lg/min/mg protein.

H. Stalder et al. / Bioorg. Med. Chem. Lett. 21 (2011) 1227–1231
1231
Acknowledgments
O
F
F
O
N
F
We thank Christian Saladin, Mathieu Gutknecht, Sylvie Chaboz,
Danièle Buchy, Veit Metzler and Roland Mory for valuable
experimental assistance.
H
N
EPPTB (RO5212773, 9f)
0.0009 µM IC50
0.028 µM (-12%) i)
0.942 µM IC50 4.54 µM
Ki > 5
Supplementary data
mTAAR1 Ki
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.bmcl.2010.12.075. These data
include MOL files and InChiKeys of the most important compounds
described in this article.
rTAAR1
hTAAR1
Ki
µM IC50 7.49 µM
SDPK (mouse)
i.p. (5 mg/kg)
Cmax
i.v. (2.5 mg/kg)
590 ng/mL
74 %
Clearance
t1/2
Vss
87 mL/min/kg
1.9 h
3.7 L/kg
References and notes
F
brain/plasma 0.5
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Figure 2. In vitro activity at TAAR1 and single dose PK data for 9f (RO5212773 =
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enous agonist b-PEA (in vitro cAMP functional assay; 100% efficacy = 0% min% stim.).
3. Berry, M. D. J. Neurochem. 2004, 90, 257.
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enzymes16 showed that at a concentration of 10
lM 9f had no
relevant affinity for any of the included targets with the exception
of the sodium channel (site 2) and the adenosine A3 receptor (cf.
Supplementary data), confirming that 9f is a selective antagonist
of mTAAR1. The first in vitro mechanistic studies with 9f (N-(3-
ethoxy-phenyl)-4-pyrrolidin-1-yl-3-trifluoromethyl-benzamide:
EPPTB = RO5212773) have recently been published.8 This selec-
tive competitive antagonist was shown to be an inverse agonist
and has enabled the elucidation of TAAR1-mediated regulatory
mechanisms in dopaminergic neurons of the mesolimbic system.
Further in vitro and in vivo studies with EPPTB are ongoing and
will be published in due course.
In summary, a series of benzanilide TAAR1 antagonists was
identified in a HTS and was optimized for potency in binding, func-
tional activity, and selectivity versus other biological targets.
EPPTB (RO5212773, 9f) was identified as a highly potent and
selective full antagonist of mTAAR1 which is suitable for use as a
pharmacological tool for in vitro and in vivo investigations. To
the best of our knowledge, EPPTB is the first selective TAAR1
antagonist disclosed.
14. Park, C.-M.; Bruncko, M.; Adickes, J.; Bauch, J.; Ding, H.; Kunzer, A.; Marsh, K. C.;
Nimmer, P.; Shoemaker, A. R.; Song, X.; Tahir, S. K.; Tse, C.; Wang, X.; Wendt, M.
D.; Yang, X.; Zhang, H.; Fesik, S. W.; Rosenberg, S. H.; Elmore, S. W. J. Med. Chem.
2008, 51, 6902.
15. PK experiments were performed using two animals per group and iv bolus or
po gavage administration. Sample analysis of blood samples and brain tissue
homogenate was performed using standard LC–MS methodology.
16. Cerep, Le bois l’Evêque, F-86600 Celle l’Evescault, France; http://www.cerep.fr.