Synthesis and structure-activity relationships of spirohydantoin-derived small-molecule antagonists of the melanin-concentrating hormone receptor-1 (MCH-R1)

Article abstract of DOI:10.1016/j.bmcl.2007.01.104

The design, synthesis, and SAR of a series of substituted spirohydantoins are described. Optimization of an in-house screening hit gave compounds that exhibited potent binding affinity and functional activity at MCH-R1.

Full text of DOI:10.1016/j.bmcl.2007.01.104

Bioorganic & Medicinal Chemistry Letters 17 (2007) 2171–2178
Synthesis and structure–activity relationships of spirohydantoin-
derived small-molecule antagonists of the melanin-concentrating
hormone receptor-1 (MCH-R1)
Martin W. Rowbottom,a,* Troy D. Vickers,a Junko Tamiya,a Mingzhu Zhang,a
Brian Dyck,a Jonathan Grey,a David Schwarz,b Christopher E. Heise,c Michael Hedrick,c
Jenny Wen,d Hui Tang,d Hua Wang,d Andrew Fisher,d Anna Aparicio,d
John Saundersa and Val S. Goodfellowa,*,ꢀ
aDepartment of Medicinal Chemistry, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA
bDepartment of Molecular Biology, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA
cDepartment of Pharmacology, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA
dDepartment of Preclinical Development, Neurocrine Biosciences Inc., 12790 El Camino Real, San Diego, CA 92130, USA
Received 4 January 2007; revised 23 January 2007; accepted 24 January 2007
Available online 4 February 2007
Abstract—The design, synthesis, and SAR of a series of substituted spirohydantoins are described. Optimization of an in-house
screening hit gave compounds that exhibited potent binding affinity and functional activity at MCH-R1.
Ó 2007 Published by Elsevier Ltd.
Melanin-concentrating hormone receptor-1 (MCH-R1)
has recently become the subject of great interest within
the pharmaceutical industry. MCH-R1 is activated by
the peptide melanin-concentrating hormone (MCH),
and it has been known for some time that in mammals,
both MCH and MCH-R1 are involved in the regulation
of feeding behavior and energy homeostasis. For in-
stance, transgenic mice overexpressing MCH peptide
are hyperphagic and obese,1 whereas those deficient in
MCH are hypophagic and lean.2 In addition, mice lack-
ing MCH-R1 are hyperphagic, lean, and resistant to
diet-induced obesity.3 Not surprisingly therefore, it
was hypothesized that a selective MCH-R1 antagonist
may be successful in treating obesity in humans.4 To this
end a number of laboratories have recently reported the
discovery of orally active small-molecule MCH-R1
antagonists effective in controlling weight gain in
rodents,5 though it still remains to be seen whether this
translates to safe clinical efficacy in humans.
As part of our efforts to discover and develop novel
small-molecule MCH-R1 antagonists,5b,6 we identified
a high-affinity ligand from an in-house high-throughput
screen (compound 1, Fig. 1). Compound 1, derived from
a spirohydantoin scaffold, exhibited a Ki of 50 nM at
N
N
O
OMe
3
N
Keywords: MCH; MCH-R1; MCH antagonists; Melanin-concentrat-
ing hormone receptor-1 antagonists; Spirohydantion; CYP3A4;
Obesity.
N
8
N
O
1
*
Corresponding authors. Tel.: +1 858 617 7600; fax: +1 858 617 7601
(M.W.R.); e-mail addresses: mrowbottom@neurocrine.com; val.
goodfellow@glpg.com
F
URL: http://www.neurocrine.com.
Present address: BioFocus-DPI, 9640 Towne Center Drive, San
Diego, CA 92121, USA.
1
ꢀ
Figure 1. Structure of MCH-R1 high-throughput screening hit.
0960-894X/$ - see front matter Ó 2007 Published by Elsevier Ltd.
doi:10.1016/j.bmcl.2007.01.104

2172
M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
MCH-R1. Unfortunately, compound 1 also proved to
be a potent inhibitor of CYP3A4 (IC50 = 35 nM). As
approximately 50% of all known drugs are metabolized
to some degree by CYP3A4, inhibition of this enzyme
in vivo can lead to undesirable drug–drug interactions.7
Therefore, any subsequent optimization campaign
would have to address not only binding and functional
activity at MCH-R1, but also the reduction of inhibition
at CYP3A4. In this letter, we describe efforts toward the
optimization of this lead, which led to the discovery of a
novel series of highly potent and functional MCH-R1
antagonists, with an improved CYP3A4 profile.
8 which can participate in a palladium-mediated Suzuki
coupling, either directly or via conversion to a pinacol
boronate ester, to yield compounds 9c–u. In addition,
copper-mediated coupling with the corresponding
N(H)-heterocycle gave compounds 9a and b. Compound
10 was obtained via the reductive alkylation of interme-
diate 7 with commercially available 3-[(4-formylphe-
nyl)methylamino]propionitrile. Variation at N-1 was
achieved via the routes outlined in Scheme 3. Unsubsti-
tuted derivative 13 was obtained in two steps from
4-amino-1-(tert-butoxycarbonyl)piperidine-4-carboxylic
acid 11 via cyclization with 3-methoxyphenyl isocyanate
followed by reductive alkylation with 3-(4-formylphe-
nyl)benzonitrile. Substituted derivatives 16a–f were ob-
tained in four steps from 4-piperidone hydrochloride 14.
Alkylation of 14 with 4-bromobenzyl bromide, then Su-
zuki coupling with 3-cyanophenyl boronic acid,
followed by a Strecker reaction with the corresponding
primary amine gave intermediates 15a–f in high yield.
Subsequent cyclization with 3-methoxyphenyl isocyanate
followed by acid hydrolysis gave the final compounds
16a–f. The N–3(H) hydantoin derivative 17 was obtained
via reaction of 15f with chlorosulfonyl isocyanate, fol-
lowed by acid hydrolysis. Compound 18 was obtained
via a copper-mediated coupling of 17 with 3-bromotolu-
ene. All final compounds described herein (Tables 1–3)
were assayed for their ability to displace radiolabeled
In order to fully explore SAR around this spirohydan-
toin scaffold, we developed synthetic strategies which en-
abled the incorporation of a variety of substituents at
both the N-1 and N-3 nitrogens of the hydantoin, and
variation of the terminal ring of the biaryl motif
(Schemes 1–3). Variation of the substituent at N-3 was
achieved via the route outlined in Scheme 1. Reductive
amination of commercially available 4-(1H-imidazol-1-
yl)benzaldehyde 2 with 4-hydroxypiperidine, then oxida-
tion to the ketone followed by a Strecker reaction
employing 2-fluorobenzylamine, gave aminonitrile 3 in
moderate yield. Cyclization to the corresponding spiro-
hydantoin was achieved using either chlorosulfonyl iso-
cyanate followed by acid hydrolysis to give N–3(H)
derivative 4, or a variety of substituted isocyanates fol-
lowed by acid hydrolysis to yield compounds 5a–h. Var-
iation of the terminal ring of the biaryl motif was
achieved as outlined in Scheme 2. Intermediate 7 was
obtained in good yield from N-benzylpiperidin-4-one 6
via a Strecker reaction with 2-fluorobenzylamine, subse-
quent cyclization with 3-methoxyphenyl isocyanate then
acid hydrolysis, followed by N-debenzylation. Reductive
alkylation with 4-bromobenzaldehyde gave intermediate
[
125I-Tyr13]-MCH in a competitive binding assay.8 The
functional antagonism of select compounds was further
confirmed based upon their ability to inhibit, in a dose-de-
pendent manner, MCH stimulated G-protein-GTPc35S
binding in cells expressing native human MCH-R1.9
We initially examined SAR around N-3 of the hydanto-
in core, keeping the substituents at both N-1 (2-fluorob-
enzyl) and N-8 [4-(imidazol-1-yl)benzyl] constant
N
N
N
O
F
N
N
H
N
a-c
d
N
N
H
N
N
N
O
N
CHO
2
3
4
F
N
e
N
O
R
N
N
N
O
F
5a-h
Scheme 1. Reagents and conditions: (a) 4-hydroxypiperidine, NaBH(AcO)3, 1,2-dichloroethane, rt, 12 h, 20%; (b) oxalyl chloride, DMSO, DCM,
À78 °C, rt, 2 h, quantitative; (c) 2-fluorobenzylamine, potassium cyanide, MeOH/H2O, 0 °C, rt, 12 h, 40%; (d) chlorosulfonyl isocyanate, DCM, rt,
1 h, then 2 N aq HCl, EtOH, 70 °C, 12 h, 20%; (e) RNCO, EtOH, rt, 5 h, then 2 N aq HCl, EtOH, 70 °C, 12 h, 10–43%.

M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
2173
MeO
MeO
N
Br
O
O
F
O
N
a-c
d
HN
N
N
N
O
N
O
6
F
7
8
h
e, or f, or g
MeO
Me
NC
MeO
N
Ar
O
F
O
N
N
N
N
N
O
N
O
F
10
9a-u
Scheme 2. Reagents and conditions: (a) 2-fluorobenzylamine, potassium cyanide, MeOH/H2O, 0 °C, rt, 21 h, 96%; (b) 3-methoxyphenyl isocyanate,
THF, rt, 8 h, then AcOH, H2O, 55 °C, 16 h, 31%; (c) H2 gas (45 psi), 20% Pd(OH)2/C, 4 N aq HCl, EtOH, rt, 72 h, quantitative; (d)
4-bromobenzaldehyde, NaBH(OAc)3, DCM, rt, 12 h, 30%; for compounds 9c–e, g, i, k, m–u; (e) ArB(OR)2, Pd(PPh3)4 or Pd(dppf)2Cl2ÆDCM,
Na2CO3, 1,4-dioxane/H2O, 100 °C, 12 h, 10–50%; for compounds 9f, h, j, l; (f) bis(pinacolato)diboron, Pd(dppf)2Cl2ÆDCM, KOAc, 1,4-dioxane,
100 °C, 12 h, then ArBr, Pd(PPh3)4 or Pd(dppf)2Cl2ÆDCM, Na2CO3, 1,4-dioxane/H2O, 100 °C, 12 h, 10–50%; for compounds 9a, b; (g)
NH-heterocycle, CuI, trans-1,2-diaminocyclohexane, Cs2CO3, 1,4-dioxane, 100 °C, 24 h, 10%; (h) 3-[(4-formylphenyl)methylamino]propionitrile,
˚
NaBH(OAc)3, 4 A ms, DCM, rt, 16 h, 36%.
(see Table 1). The unsubstituted derivative
4
CYP3A4 by chelation of the imidazole nitrogen with
the active heme iron atom of the CYP enzyme.10 We rea-
soned that replacement of the imidazole ring in this ser-
ies should result in compounds with an improved
CYP3A4 profile.
(Ki = 2, 100 nM) proved to be approximately 40-fold
less active than 1, though introduction of a simple alkyl
group did improve potency significantly, the n-butyl (5b)
and cyclohexyl (5c) derivatives having Ki’s of 200 and
340 nM, respectively. Incorporation of an unsubstituted
phenyl ring resulted in a slight improvement (5d,
Ki = 115 nM), though moving the ring further out,
either one (5e, Ki = 150 nM) or two carbons (5f,
Ki = 400 nM), proved detrimental. Attempts to improve
potency via the introduction of substituted phenyl
groups proved unsuccessful (results not shown). More
than 60 analogs were prepared incorporating a variety
of functional groups on the phenyl ring, though SAR
around this ring proved to be very flat, showing little
improvement over the 3-methoxyphenyl group incorpo-
rated in our original lead (1). An exception proved to be
the 1-naphthyl moiety (5g, Ki = 25 nM) which led to a
2-fold improvement in potency with respect to 1. Again
it seemed that the aryl ring directly attached to the core
was important, as saturation of this ring (compound 5h,
Ki = 340 nM) led to more than a 10-fold decrease in
activity. Unfortunately, all compounds described in Ta-
ble 1 still proved to be significant inhibitors of CYP3A4,
with IC50 values similar to that observed with 1. We
hypothesized that the observed inhibition of CYP3A4
may be due to the presence of the imidazole ring, as it
is well known that certain drugs containing an imidazole
(such as ketoconazole) strongly bind and inhibit
A number of biaryl derivatives were subsequently pre-
pared, as outlined in Table 2. The N-pyrrolo derivative
9b, though much less potent at MCH-R1
(Ki = 1500 nM), was also significantly less active at
CYP3A4 (IC50 > 10,000 nM),11 suggesting the imidaz-
ole ring is indeed important for potent inhibition of
CYP3A4. We discovered that the imidazole could be
replaced with either a 3-pyridyl (9c, Ki = 89 nM) or
4-pyridyl (9d, Ki = 44 nM) moiety without loss of
MCH-R1 activity. The 4-pyridyl derivative 9d was
approximately 4-fold more potent at CYP3A4 than
the 3-pyridyl analog 9c, the IC50 values being 300
and 1100 nM, respectively. Substitution around the
3-pyridyl gave interesting results, with respect to affin-
ity at MCH-R1. The 4-methyl-3-pyridyl (9f, Ki =
640 nM) and 4-methoxy-3-pyridyl (9g, Ki = 315 nM)
derivatives were less potent than the unsubstituted ana-
log 9c. The introduction of a 4-amino-3-pyridyl moiety
increased potency 4-fold (with respect to 9c), com-
pound 9h having a Ki of 20 nM. In addition, it was
interesting to observe that simply moving the 4-meth-
oxy substituent (of 9g) to either the 5- or 6-position
resulted in a greater than 20-fold increase in potency,

2174
M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
CN
O
O
O
a
b
OH
NH2
N
N
OMe
OMe
boc
N
HN
N
N
N
H
H
O
O
13
12
11
CN
CN
O
c-e
f
N
NH
H
HN
O
N
N
N
HCl
N
O
R
14
17
15a-f
g
CN
h
N
O
Me
O
OMe
N
N
N
N
N
O
N
O
R
16a-f
18
Scheme 3. Reagents and conditions: (a) 3-methoxyphenyl isocyanate, DIEA, THF, rt, then 1 N aq HCl, EtOH, 80 °C, 12 h, 50%; (b) 3-(4-
formylphenyl)benzonitrile, NaBH(OAc)3, MeOH/DCM, rt, 12 h, 90%; (c) 4-bromobenzyl bromide, K2CO3, acetonitrile, 50 °C, 6 h, 84%; (d)
3-cyanophenylboronic acid, Pd(PPh3)4, Na2CO3, toluene/H2O/EtOH, reflux, 5 h, quantitative; (e) RNH2, sodium cyanide, AcOH, H2O, rt, 12 h, 50–
90%; (f) chlorosulfonyl isocyanate, DCM, rt, 1 h, then 2 N aq HCl, EtOH, reflux, 12 h, 35%; (g) 3-methoxyphenyl isocyanate, EtOH, rt, 1 h, then 2 N
aq HCl, reflux, 2 h, 5–30%; (h) 3-bromotoluene, CuI, trans-1,2-diaminocyclohexane, Cs2CO3, 1,4-dioxane, 100 °C, 16 h, 27%.
compounds 9i and 9k exhibiting Ki’s of 13 and 8 nM,
respectively. The reasons for these observed differences
in MCH-R1 binding affinity are not clear, but overall
the data may suggest that either the pyridyl nitrogen,
or the methoxy substituent, may be involved in a key
hydrogen bonding interaction with the receptor.
Certainly replacement of the 5-methoxy (of 9i) with a
cyano group (9j, Ki = 10 nM) had no effect on potency,
presumably due to the potential of the cyano function-
ality to also act as a hydrogen bond acceptor. Unfortu-
nately, as one might expect, the incorporation of
substituted 3-pyridyl moieties in this region of the
molecule did not remove the CYP3A4 inhibition liabil-
ity. For instance, compounds 9i, 9j, and 9k had IC50
values (at CYP3A4) of 2000, 6200, and 1700 nM,
respectively. Incorporation of a substituted phenyl ring
in place of the pyridine also gave potent MCH-R1
antagonists, though the position and nature of the sub-
stituent seemed important. The 3-cyanophenyl deriva-
tive 9o (Ki = 20 nM) was approximately 10-fold more
active than the corresponding 4-isomer 9p (Ki =
210 nM), whereas surprisingly the 2-cyanophenyl
derivative was essentially inactive. The 3-methoxyphe-
nyl derivative (9q, Ki = 620 nM) was less potent, and
the presence of polar groups such as hydroxyl (9t,
Ki = 2900 nM) in this position was not well tolerated.
We also discovered that a biaryl is not necessary for
potency at MCH-R1. The propionitrile derivative 10
(Ki = 19 nM) proved equipotent to compound 9o,
again supporting the idea that it is the presence
and position of a hydrogen bond accepting motif in
this region of the molecule that is important for
potency. In addition, we were pleased to discover
that compound 9o displayed minimal CYP3A4 inhibi-
tion, the IC50 > 10,000 nM. Taking compound 9o as
our lead, we investigated SAR around N-1 of the
hydantoin core, the results of which are summarized
in Table 3.

M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
2175
Table 1. Binding affinities of spirohydantoins 1, 4, and 5a–h toward
MCH-R1
Table 2. Binding affinities of spirohydantoins 9a–u and 10 toward
MCH-R1
R
MeO
O
N
N
N
O
N
O
N
N
R
O
N
N
F
Compound
R
Ki (nM)a
F
OMe
Compound
R
Ki (nM)a
1
50
N
Me
9a
300
N
N
4
H
Et
2100
1100
200
5a
5b
n-Bu
9b
9c
9d
1500
89
5c
5d
5e
5f
340
115
150
400
N
N
44
N
N
9e
9f
330
640
Me
5g
5h
25
N
340
MeO
H2N
N
9g
9h
315
20
a Ki values are averaged from at least two experiments.8
The unsubstituted derivative 13 (Ki = 280 nM) was
approximately 14-fold less potent than 9o. It became
clear that lipophilic groups were preferred at N-1, as
incorporation of progressively larger groups led to a sig-
nificant improvement in binding affinity. For instance,
the cyclopropyl methyl (16c), cyclohexyl (16d), and
cyclohexyl methyl (16e) derivatives had measured Ki’s
of 84, 12, and 16 nM, respectively. Exchanging cyclo-
hexyl for phenyl led to a further increase in potency,
compounds 16f and 18 both exhibiting a Ki of 6 nM.
Although we had obtained very potent compounds
within this series, we were somewhat concerned as to
the size and lipophilicity of some of these analogs. For
instance, the calculated logP’s for compounds 9o, 16f,
and 18 are 6.52, 6.35, and 6.40, respectively.12 Highly
lipophilic compounds can suffer from a poor pharmaco-
kinetic profile in vivo, with poor absorption and/or high
first pass metabolism often being major contributing
N
N
MeO
NC
9i
9j
13
10
N
N
9k
8
MeO
(continued on next page)

2176
M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
Table 3. Binding affinities of spirohydantoins 13, 16a–f, and 17–19
toward MCH-R1
Table 2 (continued)
Compound
R
Ki (nM)a
R1
N
R2
9l
230
O
N
Cl
NC
O
N
R3
N
9m
9n
9o
9p
9q
2300
>10,000
20
Compound
R1
R2
R3
Ki (nM)a
OMe
OMe
13
H
H
H
280
NC
NC
16a
16b
Me
180
100
NC
210
OMe
H
MeO
620
OMe
OMe
HN
9r
9s
150
16c
16d
H
H
84
12
Me
O
HN
8000
MeO2S
HO
9t
2900
32
O
OMe
OMe
9u
16e
16f
17
H
H
H
16
Me
CN
N
Me
10
19
6
a Ki values are averaged from at least two experiments.8
factors. Indeed, compound 18 displayed very poor oral
bioavailability in rat (% F < 5),13 an issue that needed
to be addressed. SAR data discussed earlier may suggest
that the N-3 substituent does not play a critical role in
the binding of these molecules to MCH-R1 (see data
in Table 1). If correct, removal of this substituent should
significantly reduce logP without unacceptably affecting
potency. Indeed, the N–3(H) derivative 17 (Ki = 45 nM)
was only 8-fold less potent than compound 16f. Impor-
tantly, we had reduced clogP by approximately 2 log
units (to 4.77) and this decrease in clogP was reflected
in a corresponding increase in metabolic stability
and oral bioavailability. For instance, in an in vitro
human liver microsome assay, compounds 9o and
16f had scaled intrinsic clearance values of 94 and
H
45
Me
18
19
H
6
8
Cl
H
a Ki values are averaged from at least two experiments.8

M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
2177
47 mL/min/kg, respectively.14 On the other hand, com-
pound 17 had a scaled intrinsic clearance value of
25 mL/min/kg. In addition, 17 had significantly im-
proved oral bioavailability (% F = 65),15 compared to
compound 18. Compound 17 also proved to be a weak
inhibitor of CYP3A4, the IC50 being >10,000 nM.
Finally, we discovered that even without a substituent
at N-3 we could access highly potent analogs. The sim-
ple addition of a chlorine atom on the left-hand phenyl
ring improved potency as compound 19 exhibited a Ki of
8 nM.16
Hoang, M.; Young, J. R.; Chaung, D.; Eid, R.; Turner,
C.; Lin, P.; Tong, X.; Wang, J.; Tan, C.; Feighner, S.;
Palyha, O.; Hreniuk, D. L.; Pan, J.; Sailer, A. W.;
MacNeil, D. J.; Howard, A.; Shearman, L.; Stribling, S.;
Camacho, R.; Strack, A.; Van der Ploeg, L. H. T.; Goulet,
M. T.; DeVita, R. J. Bioorg. Med. Chem. Lett. 2006, 16,
5270;; (e) Hertzog, D. L.; Al-Barazanji, K. A.; Bigham, E.
C.; Bishop, M. J.; Britt, C. S.; Carlton, D. L.; Cooper, J.
P.; Daniels, A. J.; Garrido, D. M.; Goetz, A. S.; Grizzle,
M. K.; Guo, Y. C.; Handlon, A. L.; Ignar, D. M.;
Morgan, R. O.; Peat, A. J.; Tavares, F. X.; Zhou, H.
Bioorg. Med. Chem. Lett. 2006, 16, 4723.
6. (a) Hudson, S.; Kiankarimi, M.; Rowbottom, M. W.;
Vickers, T. D.; Wu, D.; Pontillo, J.; Ching, B.; Dwight,
W.; Goodfellow, V. S.; Schwarz, D.; Heise, C. E.; Madan,
A.; Wen, J.; Ban, W.; Wang, H.; Wade, W. S. Bioorg.
Med. Chem. Lett. 2006, 16, 4922; (b) Rowbottom, M. W.;
Vickers, T. D.; Dyck, B.; Grey, J.; Tamiya, J.; Zhang, M.;
Kiankarimi, M.; Wu, D.; Dwight, W.; Wade, W. S.;
Schwarz, D.; Heise, C. E.; Madan, A.; Fisher, A.;
Petroski, R.; Goodfellow, V. S. Bioorg. Med. Chem. Lett.
2006, 16, 4450; (c) Dyck, B.; Zhao, L.; Tamiya, J.;
Pontillo, J.; Hudson, S.; Ching, B.; Heise, C. E.; Wen, J.;
Norton, C.; Madan, A.; Schwarz, D.; Wade, W.; Good-
fellow, V. S. Bioorg. Med. Chem. Lett. 2006, 16, 4237; (d)
Huang, C. Q.; Baker, T.; Schwarz, D.; Fan, J.; Heise, C.
E.; Zhang, M.; Goodfellow, V. S.; Markison, S.; Gogas,
K. R.; Chen, T.; Wang, X.-C.; Zhu, Y.-F. Bioorg. Med.
Chem. Lett. 2005, 15, 3701; (e) Rowbottom, M. W.;
Vickers, T. D.; Dyck, B.; Tamiya, J.; Zhang, M.; Zhao, L.;
Grey, J.; Provencal, D.; Schwarz, D.; Heise, C. E.; Mistry,
M.; Fisher, A.; Dong, T.; Hu, T.; Saunders, J.; Goodfel-
low, V. S. Bioorg. Med. Chem. Lett. 2005, 15, 3439; (f)
Grey, J.; Dyck, B.; Rowbottom, M. W.; Tamiya, J.;
Vickers, T. D.; Zhang, M.; Zhao, L.; Heise, C. E.;
Schwarz, D.; Saunders, J.; Goodfellow, V. S. Bioorg. Med.
Chem. Lett. 2005, 15, 999.
In summary, we have disclosed SAR for a novel series of
MCH-R1 antagonists based around a spirohydantoin
core. Optimization of a high-throughput screening hit
led to analogs that exhibited high affinity for
MCH-R1, and low inhibition at CYP3A4. Examples
also demonstrated good metabolic stability in human
liver microsomes and oral bioavailability in rat.
Acknowledgments
We are indebted to Mr. John Harman, Mr. Chris Devore,
and Mr. Shawn Ayube for LC–MS support and Ms.
Monica Mistry for pharmacology support. This work
was partly supported by NIH Grant 2-R44-DK059107-
02.
References and notes
1. Ludwig, D. S.; Tritos, N. A.; Mastaitis, J. W.; Kulkarni,
R.; Kokkotou, E.; Elmquist, J.; Lowell, B.; Flier, J. S.;
Maratos-Flier, E. J. Clin. Invest. 2001, 107, 379.
2. Shimada, M.; Tritos, N. A.; Lowell, B. B.; Flier, J. S.;
Maratos-Flier, E. Nature 1998, 396, 670.
7. Lin, J. H.; Lu, A. Y. H. Clin. Pharmacokinet. 1998, 35,
361.
8. The binding assay was performed using human MCH-R1
that is modified for optimal expression in HEK293 cells.
On each assay plate, a standard antagonist of comparable
affinity to those being tested was included as a control of
plate-to-plate variability. Overall Ki values were highly
reproducible with an average standard error of the mean
of less than 45% for replicate determinations.
9. For example, compound 16e had a measured IC50 of
5.0 1.0 nM. Assays were performed using membrane
preparations of CHO cells stably expressing human MCH-
R1. Each experiment was run in the presence of MCH
peptide (10 nM), GTPc35S (0.5 nM), and GDP (10 lM).
On each assay plate, a standard antagonist of comparable
IC50 to those being tested was included as a control for
plate-to-plate variability and overall IC50 values were
highly reproducible with an average standard error of the
mean of less than 45% for replicate determinations.
10. Zhang, W.; Ramamoorthy, Y.; Kilicarslan, T.; Nolte, H.;
Tyndale, R. F.; Sellers, E. M. Drug Metab. Dispos. 2002,
30, 314.
11. Inhibition assays were carried out using microsomes
isolated from transfected cells expressing only CYP3A4,
and in the presence of the fluorescent substrate BFC.
Ketoconazole was used as a positive control.
12. Values were calculated using ACD/Labs logP database,
Advanced Chemistry Development Inc, Toronto, Ontario,
Canada (http://www.acdlabs.com).
13. In rat following a single iv dose of 2.5 mg/kg, plasma
AUC0–24h, CL, t1/2, and Vd were determined to be
789 ng h/mL, 56 mL/min/kg, 6.2 h, and 30 L/kg, respec-
3. (a) Chen, Y.; Hu, C.; Hsu, C.-K.; Zhang, Q.; Bi, C.; Asnicar,
M.; Hsiung, H. M.; Fox, N.; Slieker, L. J.; Yang, D. D.;
Heiman, M. L.; Shi, Y. Endocrinology 2002, 143, 2469; (b)
Marsh, D. J.; Weingarth, D. T.; Novi, D. E.; Chen, H. Y.;
Trumbauer, M. E.; Chen, A. S.; Guan, X.-M.; Jiang, M. M.;
Feng, Y.; Camacho, R. E.; Shen, Z.; Frazier, E. G.; Yu, H.;
Metzger, J. M.; Kuca, S. J.; Shearman, L. P.; Gopal-Truter,
S.; MacNeil, D. J.; Strack, A. M.; MacIntyre, D. E.; Van der
Ploeg, L. H. T.; Qian, S. Proc. Natl. Acad. Sci. U.S.A. 2002,
99, 3240.
4. Handlon, A. L.; Zhou, H. J. Med. Chem. 2006, 49, 4017.
5. (a) Lynch, J. K.; Freeman, J. C.; Judd, A. S.; Iyengar, R.;
Mulhern, M.; Zhao, G.; Napier, J. J.; Wodka, D.;
Brodjian, S.; Dayton, B. D.; Falls, D.; Ogiela, C.; Reilly,
R. M.; Campbell, T. J.; Polakowski, J. S.; Hernandez, L.;
Marsh, K. C.; Shapiro, R.; Knourek-Segel, V.; Droz, B.;
Bush, E.; Brune, M.; Preusser, L. C.; Fryer, R. M.;
Reinhart, G. A.; Houseman, K.; Diaz, G.; Mikhail, A.;
Limberis, J. T.; Sham, H. L.; Collins, C. A.; Kym, P. R.
J. Med. Chem. 2006, 49, 6569; (b) Dyck, B.; Markison, S.;
Zhao, L.; Tamiya, J.; Grey, J.; Rowbottom, M. W.;
Zhang, M.; Vickers, T.; Sorensen, K.; Norton, C.; Wen, J.;
Heise, C. E.; Saunders, J.; Conlon, P.; Madan, A.;
Schwarz, D.; Goodfellow, V. S. J. Med. Chem. 2006, 49,
3753; (c) McBriar, M. D.; Guzik, H.; Shapiro, S.;
Paruchova, J.; Xu, R.; Palani, A.; Clader, J. W.; Cox,
K.; Greenlee, W. J.; Hawes, B. E.; Kowalski, T. J.;
O’Neill, K.; Spar, B. D.; Weig, B.; Weston, D. J.; Farley,
C.; Cook, J. J. Med. Chem. 2006, 49, 2294; (d) Jiang, J.;

2178
M. W. Rowbottom et al. / Bioorg. Med. Chem. Lett. 17 (2007) 2171–2178
a single oral dose of 10 mg/kg, 15. In rat following a single iv dose of 2.5 mg/kg, plasma
tively. Following
plasma AUC0–24h was determined to be 26 ng h/mL.
All data were determined in male Sprague–Dawley rats
(n = 3).
AUC0–24 h, CL, t1/2, and Vd were determined to be
1079 ng h/mL, 32 mL/min/kg, 1.2 h, and 3.3 L/kg,
respectively. Following a single oral dose of 10 mg/kg,
plasma AUC0–24h was determined to be 2796 ng h/mL.
All data were determined in male Sprague–Dawley rats
(n = 3).
14. General experimental details for this assay may be found
in the following reference: Guo, Z.; Zhu, Y.-F.; Gross, T.
D.; Tucci, F. C.; Gao, Y.; Moorjani, M.; Connors, P. J.;
Rowbottom, M. W.; Chen, Y.; Struthers, R. S.; Xie, Q.;
Saunders, J.; Reinhart, G.; Chen, T. K.; Bonneville, A. L.
K.; Chen, C. J. Med. Chem. 2004, 47, 1259.
16. Compound 19 was prepared in four steps from 4-piperi-
done hydrochloride (14) using a similar procedure out-
lined for 17 (Table 3).