Cis-1-Oxo-heterocyclyl-4-amido cyclohexane derivatives as NPY5 receptor antagonists

Article abstract of DOI:10.1016/j.bmcl.2014.02.023

The NPY5 receptor binding and pharmacokinetic properties of a novel series of cis-1-oxo-heterocyclyl-4-amido-cyclohexane derivatives are described.

Full text of DOI:10.1016/j.bmcl.2014.02.023

Bioorganic & Medicinal Chemistry Letters 24 (2014) 1458–1461
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
cis-1-Oxo-heterocyclyl-4-amido cyclohexane derivatives as NPY5
receptor antagonists
James Ford Burns a, Bin Chen a, Chien-An Chen a, Dario Doller a, Eman Edelmenky a, Yu Jiang a,
John M. Peterson a, , Michael Sabio a, Jessie Weiss a, Andrew D. White a, Lingyun Wu a,
⇑
Rajinder Bhardwaj a, Gamini Chandrasena a, Noel J. Boyle b, Xinyan Huang b
a Department of Chemical and Pharmacokinetic Sciences, Lundbeck Research USA, 215 College Road, Paramus, NJ 07652, USA
b Department of Biological Research, Lundbeck Research USA, 215 College Road, Paramus, NJ 07652, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
The NPY5 receptor binding and pharmacokinetic properties of a novel series of cis-1-oxo-heterocyclyl-4-
amido-cyclohexane derivatives are described.
Received 1 November 2013
Revised 5 February 2014
Accepted 7 February 2014
Available online 15 February 2014
Ó 2014 Elsevier Ltd. All rights reserved.
Keyword:
Neuropeptide Y5 receptor antagonist
Neuropeptide Y (NPY) is a 36 amino acid peptide widely
expressed in the central and peripheral nervous systems.1 NPY
influences a diverse array of biological functions including: blood
pressure; food intake; circadian rhythms; cognition; and stress
sensitivity.2–5 NPY exerts its effects via interaction with specific
receptors of the GPCR superfamily. Five NPY receptor subtypes
have been identified to date (Y1, Y2, Y4, Y5, and Y6).6 The NPY5
receptor is well known for its role in appetite.7–9 We have reported
that the NPY5 receptor might also modulate stress sensitivity.10 In
order to better understand the function of the NPY5 receptor,
selective agonists and antagonists are required. Many NPY5 antag-
onist chemotypes have been reported (Fig. 1).11–14 Two
compounds, MK0557 from Merck and velneperit from Shionogi,
have advanced to human clinical trials. Both compounds induced
statistically significant weight loss in obese subjects.15,16
In designing the new series of compounds, we noted the 1,4-cis
arrangement of the amide and the pyridyl ring in MK0557. We rea-
soned that an oxo-heterocycle could replace the pyridine, and that
such a compound would prefer to have the amide axially disposed
as in MK0557 (Fig. 2).21
Synthesis of lactam compounds is outlined in Scheme 1. Reduc-
tive amination of the ketoester 5 with an aminoester 6 afforded a
mixture of cis and trans lactams 7. Ester hydrolysis, separation of
the diastereomeric acids, and amidation with a (30,50-difluoro-
phenyl)-2-aminoheterocycle provided compounds 9. Methylation
of amide 9a provided compound 10.
We were pleased to find that the cis-butyrolactam 9a had
potent NPY5 binding affinity while the trans isomer 9b was much
weaker (Table 1). The amide hydrogen seems important for
F
We have recently reported SAR studies of
a series of
F3C
O
N
O
benzothiazepines, such as 4, and their derivatives.17–19 Unfortu-
nately, we were unable to overcome the physico-chemical and
pharmacokinetic liabilities of these series’. This Letter describes
the identification of a series of novel cis-1-oxo-heterocyclyl-4-
amido cyclohexane derivatives as potent NPY5 receptor antago-
nists having desirable PK properties.20
N
N
H
N
N
N
H
SO2t-Bu
N
H
O
O
MK0557
velneperit
1
2
H
N
H
N
CH3
N
N
N
N
F
S
O
N
N
SO2CH3
SO2CH3
H
S
⇑
Corresponding author at present address: GlycoMimetics Inc, 401 Professional
Drive, Suite 250, Gaithersburg, MD 20879, USA. Tel.: +1 8605101270.
F
SCH500946
Lu AA33810
3
4
E-mail address: johnptrsn74@gmail.com (J.M. Peterson).
Figure 1. Representative NPY5 receptor antagonists.
http://dx.doi.org/10.1016/j.bmcl.2014.02.023
0960-894X/Ó 2014 Elsevier Ltd. All rights reserved.

J. F. Burns et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1458–1461
1459
Ar
N
Ar
N
O
a, b
O
O
Cl
O
O
H
H
N
Cl
MeO2C
RO2C
c
NH2
+
N
n
X
O
N
H
H
11
12
13
R = Me
O
O
H
14 R = H
O
F
O
O
d
Figure 2. Design rationale.
O
N
H
N
F
N
15
RO2C
a
EtO2C
O
c, d
Scheme 2. Reagents and conditions: (a) NEt3, DCM; (b) K2CO3, CH3CN, reflux; (c)
NaOH, MeOH, H2O; (d) (1) SOCl2, CH2Cl2, rt, (2) ArNH2, DIEA, DCE, rt.
H2
N
CO2Et
n
+
N
+
O
n
5
6
7
8
R = Et
R = H
b
O
F
F
a, b
O
O
R
MeO2C
MeO2C
NH2
N
+
R
F
O
F
O
e
11
16a-c
17
R =Me
c
18 R = H
N
N
N
N
H
O
O
CH3
N
N
F
9a-e
10
n
n
O
O
d, e
O
N
N
H
Scheme 1. Reagents and conditions: (a) NaBH(OAc)3, DCE, reflux; (b) NaOH, THF,
MeOH, H2O, rt; (c) HPLC separation; (d) (1) Oxalyl chloride, DCE, (2) 5-(3,5-
Difluoro-phenyl)-pyridin-2-ylamine, TEA, DCM; (e) NaH, MeI, DMF.
F
N
R
19a-c
Scheme 3. Reagents and conditions: (a) EtOH, 65 °C; (b) Phosgene, DCM, Toluene;
(c) NaOH, MeOH, H2O; (d) (1) SOCl2, CH2Cl2, rt, (2) ArNH2, DIEA, DCE, rt.
binding as the N-methyl analog 10 is devoid of activity. Consider-
ing the central heterocycle, the pyrimidine and pyrazine analogs 9c
and 9d, respectively, were equipotent with pyridine 9a. The larger
valerolactam 9e was equipotent with the butyrolactam 9a.
Being convinced that our design rationale was sound, we
explored other oxo-heterocycles keeping the 5-(30,50-difluoro-
phenyl)-pyridin-2-ylamine constant.
Oxazolidinone analogs were prepared according to Schemes 2
and 3. Acylation of aminoester 11 with chloroethylchloroformate,
followed by cyclization, ester hydrolysis and amidation provided
compound 15 (Scheme 2). Substituted oxazolidinones were pre-
pared by opening epoxides 16a–c with aminoester 11 followed
by cyclization with phosgene, ester hydrolysis and amidation
(Scheme 3).
Oxazolidinone 15 was equipotent with lactam 9a (Table 2).
Considerable space exists off the 5-position of the oxazolidinone
as the methyl and tert-butyl analogs 19a–c were equally active
as 15. The lack of a stereochemical preference for binding potency
as seen by comparing 19a with 19b suggests this may be a solvent
exposed region.
Imidazolidinone and pyrimidinone analogs were prepared
according to Scheme 4. Reductive amination of ketoester 5 with
a BOC protected diamine 20 followed by deprotection and cycliza-
tion provided imidazolidinone and pyrimidinone esters which
could be N-alkylated if desired. Ester hydrolysis followed by ami-
dation provided the target compounds 23a–g. Binding data for
these compounds is summarized in Table 3.
Imidazolidinone 23a is equipotent with pyrimidinone 23c. The
heterocyclic hydrogen atom of these compounds does not seem
to be involved in a specific binding interaction as the N-methylated
analogs 23b and 23d do not lose affinity. Enlarging the alkyl group
to ethyl (23d) or cyclopropyl (23g) retains potency while the iso-
propyl analog 23f suffers a modest loss in potency.
Solubility and microsomal stability data are summarized in
Tables 1–3 for selected analogs. The solubility at pH7.4 of various
oxo-heterocycles are below 10 lg/mL with the exception of lactam
9c (Table 1) having a central pyrimidine. This suggests that the
central heterocycle has a larger effect on the physico-chemical
Table 1
SAR of lactams
F
O
N
Y
X
N
N
n
R
O
F
a
b
b
Compd
cis/trans
X
Y
n
R
hY5 Ki10 (nM)
Sol7.4
(
lg/mL)
hCLint (L/min)
rCLint (mL/min)
9a
9b
10
9c
9d
9e
cis
trans
cis
cis
cis
CH
CH
CH
N
CH
CH
CH
CH
CH
CH
N
1
1
1
1
1
2
H
H
CH3
H
H
8
720
>10 k
5
0.7
—
—
38
—
—
1.0
—
—
0.7
0.9
—
12
—
—
31
9.5
—
6
2
cis
CH
H
a
Classic shake flask with HPLC-UV measurement. 0.5–1.0 mg of solid was shaken for 12 h, and then settled for 8 h, filtered and measured using HPLC-UV detection.
Maximum values are ca. 1 mg/mL.
b
A 1
lM test compound in either rat or human (pooled) liver microsomes (0.5 mg/mL) incubated at 37 °C for 0, 5, 15, 30, 60 min with NADPH regenerating system.
Following incubation, the acetonitrile quenched reaction samples were centrifuged to afford the supernatant for LC/MS analysis.

1460
J. F. Burns et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1458–1461
Table 2
SAR of oxazolidinones
R
F
O
N
N
O
N
H
O
F
a
b
b
Compd
R
R/S
hY5 Ki10 (nM)
Sol7.4
(
lg/mL)
hCLint (L/min)
rCLint (mL/min)
15
H
—
R
S
8
3
7
4
4
0.4
0.9
1.1
3.9
9.5
7
15
25
19a
19b
19c
5-Me
5-Me
5-tBu
—
—
—
R/S
a
Classic shake flask with HPLC-UV measurement. 0.5–1.0 mg of solid was shaken for 12 h, and then settled for 8 h, filtered and measured using HPLC-UV detection.
Maximum values are ca. 1 mg/mL.
b
A 1 lM test compound in either rat or human (pooled) liver microsomes (0.5 mg/mL) incubated at 37 °C for 0, 5, 15, 30, 60 min with NADPH regenerating system.
Following incubation, the acetonitrile quenched reaction samples were centrifuged to afford the supernatant for LC/MS analysis.
Table 4
O
Total plasma and brain exposure, 10 mg/kg, PO, 1 h22
a, b, c
R'
H2N
BOC
N
N
H
EtO2C
RO2C
d
O
+
N
Compd
Brain (
Plasma (
B/P
9a
9c
15
23a
23b
n
n
5
20
21 R =Et
l
M)
2.8
2.8
1.0
0.38
2.8
0.14
1.5
3
0.5
1.4
6.8
0.2
3.1
5.0
0.6
22
R = H
l
M)
F
O
O
e, f
R'
N
N
H
N
Table 5
Rat pharmacokinetic parameters for select compounds23
F
N
n
23a-g
Compd T1/2 (h) Vss (L/kg) Cl (L/h/kg) Oral AUC0–inf (ng/mL/h) F (%)
Scheme 4. Reagents and conditions: (a) NaBH(OAc)3, DCM, rt; (b) (1) HCl, DCM,
dioxane, (2) CDI, TEA, DCM; (c) R0I, NaH, DMF; (d) NaOH, MeOH, H2O; (e) (1) SOCl2,
CH2Cl2, rt, (2) ArNH2, DIEA, THF, reflux; (f) HPLC separation.
9a
15
23b
4.4
2.8
3.5
3.2
3.4
2.8
0.52
0.85
0.57
4300
2000
4100
110
83
110
IV dose was 1 mg/kg, PO dose was 2 mg/kg; formulated in 20% 2-hydroxy-propyl-b-
cyclodextrin solution in water.
properties of these compounds than the oxo-heterocycle. Human
in vitro intrinsic clearances for those compounds tested ranges
from moderate to high, most being between 0.7 and 1.1L/min. An
exception is the oxazolidinone 15 with hClint = 0.4L/min (Table 3).
Rat in vitro intrinsic clearances values range from low (9a) to high
(23a).
high total brain levels. The imidazolidinones 23a and 23b also had
high plasma exposure. The methylated imidazolidinone 23b had
higher brain levels than the non-methylated 23a.
Based on their acceptable brain levels, compounds 9a, 15, and
23b were evaluated in IV-PO PK studies. The results are summa-
rized in Table 5.
Representative analogs were evaluated for their in vivo PK
properties. The total plasma and brain levels measured 1 h after
dosing at 10 mg/kg PO are listed in Table 4.
All three compounds displayed high oral bioavailability. That of
compound 15 was a bit lower than the other two compounds most
likely due to its higher oral systemic clearance. This higher
clearance is also reflected in the lower oral AUC of compound 15
We were pleased to see that the lactam 9a showed good plasma
exposure and brain penetration. The more soluble pyrimidine ana-
log 9c had equal plasma exposure but lower total brain levels. The
oxazolidinone 15 had similar plasma exposure to 9a and 9c and
Table 3
SAR of imidazolidinones and pyrimidinones
F
O
N
N
n
R
N
N
H
O
F
a
b
b
Compd
n
R
hY5 Ki10 (nM)
Sol7.4
(l
g/mL)
hCLint (L/min)
rCLint (mL/min)
23a
23b
23c
23d
23e
23f
1
1
2
2
1
1
1
H
Me
H
5
5
9
12
10
41
9
4.5
1.1
1.3
5.4
1.6
—
1.7
0.8
1.1
1.1
1.6
—
37
8.8
18
19
17
—
Me
Et
iPr
cPr
23g
—
1.0
8.4
a
Classic shake flask with HPLC-UV measurement. 0.5–1.0 mg of solid was shaken for 12 h, and then settled for 8 h, filtered and measured using HPLC-UV detection.
Maximum values are ca. 1 mg/mL.
b
A 1
lM test compound in either rat or human (pooled) liver microsomes (0.5 mg/mL) incubated at 37 °C for 0, 5, 15, 30, 60 min with NADPH regenerating system.
Following incubation, the acetonitrile quenched reaction samples were centrifuged to afford the supernatant for LC/MS analysis.

J. F. Burns et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1458–1461
1461
13. Okuno, T.; Takenaka, H.; Aoyama, Y.; Kanda, Y.; Yoshida, Y.; Okada, T.;
Hashizume, H.; Sakagami, M.; Nakatani, T.; Hattori, K.; Abstracts of Papers,
240th ACS National Meeting, Boston, MA, 2010, MEDI-284.
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X.; McCombie, S.; Stamford, A.; Parker, E. Eur. J. Pharmacol. 2008, 601, 1.
15. Erondu, N.; Gantz, I.; Musser, B.; Suryawanshi, S.; Mallick, M.; Addy, C.; Cote, J.;
Bray, G.; Fujioka, K.; Bays, H.; Hollander, P.; Sanabria-Bohorquez, S. M.; Eng,
W.; Langstrom, B.; Hargreaves, R. J.; Burns, H. D.; Kanatani, A.; Fukami, T.;
MacNeil, D. J.; Gottesdiener, K. M.; Amatruda, J. M.; Kaufman, K. D.; Heymsfield,
S. B. Cell Metab. 2006, 4, 275.
versus the other two. All three had high volumes of distribution. In
addition all three had half-lives conducive to in vivo efficacy
assessment.
In summary, we have discovered a novel series of cis-1-
oxoheterocycly-4-amido-cyclohexane derivatives with potent
NPY5 receptor affinity having desirable PK properties. Further
in vivo characterization of compound 23b will be reported in due
course.
16. Shionogi and Co. Ltd, Research and Development at Shionogi, March 27, 2009
http://www.shionogi.co.jp/ir_en/explanatory/pdf/e_p090327.pdf.
Acknowledgments
17. Packiarajan, M.; Marzabadi, M. R.; Desai, M.; Lu, Y.; Noble, S. A.; Wong, W. C.;
Jubian, V. J.; Chandrasena, G.; Wolinsky, T. D.; Zhong, H.; Walker, M. W.;
Wiborg, O.; Andersen, K. Bioorg. Med. Chem. Lett. 2011, 21, 5436.
18. Wu, L.; Lu, K.; Desai, M.; Packiarajan, M.; Joshi, A.; Marzabadi, M. R.; Jubian, V.
J.; Andersen, K.; Chandrasena, G.; Boyle, N. J.; Walker, M. J. Bioorg. Med. Chem.
Lett. 2011, 21, 5573.
19. Packiarajan, M.; Coate, H.; Desai, M.; Jiminez, H. N.; Reinhard, E. J.; Jubian, V. J.;
Marzabadi, M. R.; Chandrasena, G.; Wolinski, T. C.; Walker, M. J.; Andersen, K.
Bioorg. Med. Chem. Lett. 2011, 21, 6500.
The authors thank Manuel Cajina, Megan Nattini, Kimloan
Nguyen and Dr. Maria Bacolod for providing bioanalysis, PK and
metabolic stability data, respectively. In addition, the authors
thank Dr. Chi Zhang for providing solubility data and Dr. Xu Zhang
for providing HPLC support.
20. Chen, Bin; Burns, James Ford; Doller, Dario; WO201010852, 2010.
21. Iida, T.; Satoh, H.; Maeda, K.; Yamamoto, Y.; Asakawa, K.; Sawada, N.; Wada, T.;
Kadowaki, C.; Itoh, T.; Mase, T. J. Org. Chem. 2005, 70, 9222.
Supplementary data
22. Femoral artery cannulated Sprague–Dawley male rats were purchased from
Taconic Laboratories. The average body weight was 300–350 g. Each
compound that was dissolved in an appropriate vehicle was orally
administered to three rats (N = 3) at a dose of 10 mg/kg. Blood samples were
collected at four time points: predose (0 h), 1, 2, and 4 h. The rats were then
sacrificed, and the brain tissues were collected and immediately stored at
ꢀ80 °C. Plasma samples were obtained by centrifuging the blood samples. To
increase bioanalysis throughput, an equal amount of N = 3 plasma or brain
samples at the same time point, which were collected from three different rats,
were pooled together. Each pooled rat brain sample was homogenized in an
aqueous solution. Protein precipitation of the pooled plasma or homogenized
brain sample afforded a supernatant that was analyzed by LC/MS/MS, an
Agilent 1100 HPLC (Agilent Technologies, Palo Alto, CA) and a TSQ Quantum
MS (ThermoFinnigan, San Jose, CA). Compound concentrations in the plasma
and brain matrices were quantified using ThermoFinnigan Xcalibur.
23. IV-PO PK protocol: Surgeries were performed under Lundbeck IACUC
established guidelines. Catheters were implanted in the left carotid artery
and right jugular vein of Male Sprague–Dawley rats (Charles River Labs)
weighing about 250–300 g. Animals were allowed to recover for 48 h with
continuous heparin/saline infusion. Following 48 h recovery period, the carotid
artery catheter was connected to the automated blood sampling system (Dilab
AccusamplerÒ) for serial blood sampling. Pre-formulated IV (1 mg/kg) drug
dose was administered via jugular vein and commenced automated sampling
up to 20 h. The same rats (n = 2) were dosed PO (2 mg/kg) in a crossover
manner, following a 24 h washout period, and proceeded automated serial
sampling up to 20 h. Blood samples were centrifuged at 3500 rpm for 15 min at
4 °C, and plasma was harvested and frozen until analysis. The plasma drug
concentrations were measured using LC/MS.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2014.02.
023.
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