Novel non-peptidic neuropeptide Y Y2 receptor antagonists

Article abstract of DOI:10.1016/j.bmcl.2003.12.057

Through SAR studies of a piperidinylindoline cinnamide HTS lead, the first potent, non-peptide, low molecular weight selective Neuropeptide Y Y ₂ (NPY Y₂) antagonists have been synthesized. The SAR studies around the piperidinyl, the indolinyl, and the cinnamyl moieties are discussed.

Full text of DOI:10.1016/j.bmcl.2003.12.057

Bioorganic & Medicinal Chemistry Letters 14 (2004) 1239–1242
Novel non-peptidic neuropeptide Y Y2 receptor antagonists
Jill A. Jablonowski,a,* Wenying Chai,a Xiaobing Li,c Dale A. Rudolph,a
William V. Murray,c Mark A. Youngman,b Scott L. Dax,b Diane Nepomuceno,a
Pascal Bonaventure,a Timothy W. Lovenberga and Nicholas I. Carruthersa
aJohnson & Johnson Pharmaceutical Research and Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA
bJohnson & Johnson Pharmaceutical Research and Development, L.L.C, Welsh and Mckean Roads, PO Box 776,
Spring House, PA 19477, USA
cJohnson & Johnson Pharmaceutical Research and Development, L.L.C., 1000 Route 202, PO Box 300, Raritan, NJ 08869, USA
Received 13 November2003; accepted 10 December2003
Abstract—Through SAR studies of a piperidinylindoline cinnamide HTS lead, the first potent, non-peptide, low molecular weight
selective Neuropeptide Y Y2 (NPY Y2) antagonists have been synthesized. The SAR studies around the piperidinyl, the indolinyl,
and the cinnamyl moieties are discussed.
# 2003 Elsevier Ltd. All rights reserved.
Neuropeptide Y (NPY) is a 36 amino acid C-amidated
peptide, which is highly expressed in both the central
and peripheral systems.1 The high abundance of NPY in
the brain and its localization suggests the involvement
of NPY in a variety of physiological processes such as
anxiety, food intake, waterconsumption, cciradian
rhythms, hormone release, learning and memory.1
Pharmacological and molecular biological studies on
NPY identified five NPY receptors (Y1, Y2, Y4, Y5 and
Y6).2,3 While most medicinal chemistry efforts have
focused on the Y1 and Y5 receptors, we chose to develop
small molecule modulators of the Y2 receptor.4 The Y2
receptor is found in several areas of the brain including
the septum, hypothalamus, hippocampus, substantia
nigra and cerebellum.1 Recently this receptor has gained
considerable interest because of its possible role in the
regulation of food intake5ꢀ7 and bone formation.8,9
limited due to theirpeptidic nature and high molecular
weight.
Following the set-up and validation of a neuropeptide Y
Y2 receptor binding assay,12 high throughput screening
of our corporate compound collection was undertaken.
A series of small molecule Y2 ligands, exemplified by
piperidinylindoline cinnamide JNJ-2765074 (1), (IC50=4
mM) were identified and a medicinal chemistry program
was initiated to evaluate the SAR forthese Y 2 ligands.
The piperidinylindoline cinnamide can be dissected into
three readily prepared fragments and the general syn-
thetic method for the preparation of analogues is shown
in Scheme 1.13 We found it necessary to initially couple
the indoline portion (3) with the piperidone moiety (2),
followed by attachment to the cinnamide residue (5).
Attempts to prepare our analogues by combining the
indole (3) with the cinnamide portion (5), followed by
coupling to the piperidinyl moiety (2) were unsuccessful.
Previous work in the discovery of NPY Y2 ligands
includes the research of Grouzmann and co-workers.
They described a peptide-based ligand, T4-[NPY 33-
36]4, which showed considerable affinity (IC50=67 nM)
forthe NPY Y 2 receptor.10 Also, Doods and co-workers
reported on BIIE0246, which also binds to the NPY Y2
receptor with good affinity (IC50=3.3 nM).11 However,
the therapeutic potential of these compounds may be
The role of the acetyl substituted indoline ring was
investigated initially, as shown in Table 1, and it was
determined that N-1 substituted analogues such as for-
myl analogue 8,14 acetyl acetate compound 9, glyoxylate
10, and N-methyl substituted indoline 11 retained bind-
ing activity that was comparable to the lead. All other
analogues including unsubstituted indoline 12, and the
methylsulfonyl 13 and the trifluoromethyl acetyl 14
* Corresponding author. Tel.: +1-858-784-3011; fax: +1-858-450-
2049; e-mail: jjablono@prdus.jnj.com
0960-894X/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2003.12.057

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J. A. Jablonowski et al. / Bioorg. Med. Chem. Lett. 14 (2004) 1239–1242
analogues displayed greatly decreased activity at the Y2
receptor.
tyl-tetrahydroquinolinyl) compound 15 retained modest
activity as shown in Table 2. However, the 6-(2-oxoin-
doline) 1616 and the 6-(N-acetyl-indolyl) 1717 showed
little binding at the NPY Y2 receptor.
Major structural modifications to the indoline portion
of the molecule were also made, as shown in Table 2.
These compounds were found to be significantly less
active than the N-acetylindoline lead (1). The 7-(N-ace-
Since all modifications to the indoline led to a decrease
in binding affinity, chemistry efforts were directed towards
the cinnamide portion of lead 1, as shown in Table 3.
Early work demonstrated that the olefin was essential
foractivity as seen in satuarted analogue 18, although
cyclopropyl substituted compound 19 showed modest
binding affinity (IC50=11 mM). The cinnamide carbonyl
was also found to be a critical component to maintain
affinity forthe NPY Y receptor. When removed (20),
2
orreplaced with a sulfone ( 21), the resulting molecules
exhibited minimal activity. Acetylene linked compound
22 was found to have modest affinity while the (Z)-ole-
fin isomer 23, prepared through a modification of the
Horner–Wadsworth–Emmons reaction,18 showed 5-fold
less affinity than the (E)-isomer( 1). In contrast, analo-
gue 24, which contains an additional olefin, displayed
activity comparable to the lead (1).
Scheme 1. General preparation of piperidinylindoline cinnamide ana-
logues. (a) 1.0 equiv ketone 2, 1.2 equiv amine 3, Na(OAc)3BH (1.6
equiv), DCE orDCM; (b) (i) 5 (X¼OH, 1.5 equiv), (COCl)2 (1.8
equiv), DMF (cat.), DCM, 0 ꢃC–rt; (ii) amine 4 (1 equiv), Et3N (2
equiv), DCM; (c) when R2=H, (i) R3CO2H, DCC, DCM or(ii)
R3COCl orR 3SO2Cl, Et3N, DCM.
Replacements forthe phenyl moiety of the cinnamide
were then studied, as shown in Table 4. Acrylamide
25 possessed minimal binding affinity, whereas the
3-thiophenyl analogue 26 was approximately equipotent
Table 1. N-1 Substituted indole analogues and theiraffinity at the
NPY Y2 receptor
Table 3. Initial SAR of the cinnamide portion
Binding affinity15
No.
R=
Binding affinity15
No.
R=
IC50, mM
IC50, mM
18
19
20
21
22
23
24
CO(CH2CH2)C6H5
anti-CO (C3H4) C6H5
CH2CH=CHC6H5
18ꢁ1
11ꢁ1
30
1
8
9
10
11
12
13
14
COCH3
CHO
CO(CH2)COCH3
CO(CO)OCH2CH3
CH3
4ꢁ0.6
3.5ꢁ0.4
4.8ꢁ0.5
4.8ꢁ0.4
5.3ꢁ0.3
22ꢁ1
(E)-SO2-CH=CHC6H5
COCꢂCC6H5
30
9.2ꢁ0.5
22ꢁ1.0
2.8ꢁ0.09
(Z)-COCH=CHC6H5
(E,E)-CO(CH=CH)2C6H5
H
SO2CH3
COCF3
15a
30
a n=1 forthis compound.
Table 4. Representative olefin analogues and their binding affinity to
the NPY Y2 receptor
Table 2. Indoline replacement analogues and their affinity at the
NPY Y2 receptor
No.
R=
Binding affinity15
IC50, mM
25
26
27
28
29
30
31
H
30
3.2ꢁ0.2
30
No.
R=
Binding affinity15
3-Thiophenyl
2-Pyridyl
3-Pyridyl
4-Pyridyl
4-Pyridyl-N-oxide
2-(Imidazolyl)
IC50, mM
30
15
16
17
7-(N-Acetyl-tetrahydroquinolinyl)
6-(2-oxoindoline)
6-(N-acetyl-indolyl)
10a
30a
30
12a
30
17a
a n=1 forthis compound.
a n=1 forthis compound.

J. A. Jablonowski et al. / Bioorg. Med. Chem. Lett. 14 (2004) 1239–1242
1241
to lead 1. This portion of the molecule also appeared to
be sensitive to subtle changes in electronics, which were
exemplified by significant differences in activity for
compounds bearing the 2-pyridyl (27), 3-pyridyl (28)
and 4-pyridyl (29) substitution. The 2- and 3-pyridyl
analogues retain only minimal activity at the NPY Y2
receptor, while the 4-pyridyl binds modestly with
IC50=12 mM. Oxidation of analogue 29 provided the 4-
pyridyl-N-oxide analogue 30, which was inactive. Slight
activity was also seen in the compound with 2-imidazo-
lyl substitution as shown in analogue 31.
benzyl moiety with a benzoate (46) led to a significant
loss in affinity suggesting the need fora basic amine.
The length of the linkeralso significantly affected bind-
ing. Phenethyl analogue 47 also showed a decrease in
activity whereas the phenpropyl analogue 48 displayed a
slight increase in binding affinity. Replacing the phenyl
group with a cyclohexyl group (49) improved activity
and when the linkerwas also extended ( 50) an addi-
tional increase in affinity (IC50=0.6 mM) was observed.
The cyclopentyl ethyl group in this position (51) pro-
vided a compound with comparable activity.
Substitution on the benzene ring of the cinnamide moi-
ety was explored next and several general trends
emerged, as shown in Table 5. Substitution in the 3-
position was preferred, with slightly lower affinity seen
when the same substituent was in the 4-position, as
demonstrated by compounds 32 (3-Cl, IC50=3.0 mM)
and 33 (4-Cl, IC50=3.6 mM). However, the CF3 sub-
stituted compounds did not follow this general trend as
seen in compounds 34–36. The receptor was tolerant of
both electron donating (CH3) and electron withdrawing
(NO2) substituents in the 3-position, as seen in the
comparable activities of compounds 37–41. However,
the 3-SOCF3 analogue 42 showed slightly loweraffinity
Several structural modifications were made to the sub-
stituted piperidine moiety and all resulted in compounds
with significantly reduced affinity at the NPY Y2 recep-
toras seen in Figure 1.
Lastly we combined the best modifications from the
piperidine portion of lead 1, namely the cyclopentyl-
ethyl and the cyclohexylethyl groups, with those from
the cinnamide work, the 4-Cl, 3-CN or 3-NO2, to pre-
pare the compounds shown in Table 7. In the initial
SAR studies, it was determined that the N-acyl-6-indo-
linyl substituent was optimal forreceptorbinding. Thus
this section of the molecule was left unchanged. Cinna-
mide substitution did not significantly alterthe binding
affinity of the cyclohexylethyl analogues 56 or 57.
forthe Y receptor at IC50=5.8 mM. The 3,5-difluoro
2
(43) and the 3,5-dimethyl (44) substituted compounds
displayed comparable activity at IC50=2.5 mM and 3.9
mM, respectively. In contrast, the 3,5-dichloro (45) ana-
logue showed only minimal activity at the NPY Y2
receptor at IC50=30 mM.
Table 6. Representative piperidine substituted analogues and their
binding affinity to the NPY Y2 receptor
Initial exploration of the N-benzylpiperidine portion of
the lead compound 1 began by varying the length and
nature of the linker connecting the phenyl group to the
piperidine nitrogen, as shown in Table 6. Replacing the
Table 5. Representative cinnamide analogues and their binding
affinity to the NPY Y2 receptor
No.
R=
Binding affinity15
IC50, mM
46
47
48
49
50
51
C6H5CO
C6H5(CH2)2
C6H5(CH2)3
C6H11CH2
C6H11(CH2)2
C5H9(CH2)2
29ꢁ1
26ꢁ3
2.3ꢁ0.3
1.1ꢁ0.08
0.6ꢁ0.04
0.8ꢁ0.02
No.
X=
Binding affinity15
IC50, mM
32
33
34
35
36
37
38
39
40
41
42
43
44
45
3-Cl
4-Cl
4-CF3
3-CF3
2-CF3
3-Br3.3
3-F
3-CH3
3-NO2
3-CN
3.0ꢁ0.3
3.6a
2.8ꢁ0.2
8.9ꢁ1.0
30a
ꢁ0.5
3.6ꢁ0.4
1.4ꢁ0.2
1.9ꢁ0.3
1.0ꢁ0.8
5.8ꢁ0.3
2.5ꢁ0.2
3.9ꢁ0.2
30a
3-SOCF3
3,5-Difluoro
3,5-diCH3
3,5-diCl
Figure 1. Structurally modified piperidine analogues:15 an=1 forthis
compound.
a n=1 forthis compound.

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J. A. Jablonowski et al. / Bioorg. Med. Chem. Lett. 14 (2004) 1239–1242
Table 7. Representative combination analogues and their binding
affinity to the NPY Y2 receptor
References and notes
1. Kaga, T.; Fujimiya, M.; Inui, A. Peptides 2001, 22, 501.
2. Blomqvist, A. G.; Herzog, H. Trends Neurosci. 1997, 20,
294.
3. Michel, M. C.; Beck-Sickinger, A.; Cox, H.; Doods, H. N.;
Herzog, H.; Larhammar, D.; Quirion, R.; Schwartz, T.;
Westfall, T. Pharmacol. Rev. 1998, 50, 143.
4. Parker, E.; Van Heck, M.; Stamford, A. Eur. J. Pharma-
col. 2002, 440, 173.
5. Naveilhan, P.; Hassani, H.; Canals, J. M.; Ekstrand, A. J.;
Larefalk, A.; Chhajlani, V.; Arenas, E.; Gedda, K.;
Svensson, L.; Thoren, P.; Ernfors, P. Nat. Med. 1999, 5,
1188.
6. Batterham, R. L.; Cowley, M. A.; Small, C. J.; Herzog,
H.; Cohen, M. A.; Dakin, C. L.; Wren, A. M.; Brynes,
A. E.; Low, M. J.; Ghatel, M. A.; Cone, R. D.; Bloom,
S. R. Nature 2002, 418, 650.
No.
R=
X=
Binding affinity15
IC50, mM
56
57
58
59
60
C6H11(CH2)2
C6H11(CH2)2
C5H9(CH2)2
C5H9(CH2)2
C5H9(CH2)2
4-Cl
3-NO2
4-Cl
3-NO2
3-CN
1.1ꢁ0.1
0.5ꢁ0.09
1.1ꢁ0.1
0.35ꢁ0.05
0.1ꢁ0.01
7. Sainsbury, A.; Schwartzer, C.; Couzens, M.; Fetissov, S.;
Furtinger, S.; Jenkins, A.; Cox, H. M.; Sperk, G.; Hok-
felt, T.; Herzog, H. Proc. Natl. Acad. Sci. U.S.A. 2002, 99,
8938.
8. Baldock, P. A.; Sainsbury, A.; Couzens, M.; Enriquez,
R. F.; Thomas, G. P.; Gradiner, E. M.; Herzog, H. J.
Clin. Invest. 2002, 109, 915.
9. Herzog, H. Drug News Perspect. 2002, 15, 506.
10. Grouzmann, E.; Buclin, T.; Martire, M.; Cannizzaro, C.;
Dorner, B.; Razaname, A.; Mutter, M. J. Biol. Chem.
1997, 272, 7699.
Conversely, the cyclopentylethyl analogues 58–60 dis-
played a wide range of activities. No change in activity
was seen with the 4-Cl cinnamide 58 and a slight
increase in activity was observed in the 3-NO2 cinna-
mide substituted analogue, 59. However, the 3-CN cin-
namide analogue (60) showed a marked increase in
binding activity at IC50=0.1 mM. Through combining
the optimal substitution on the indoline, the cinnamide
and the piperidine, we prepared the most potent
analogue, 60.
11. Doods, H.; Gaida, W.; Wieland, H. A.; Dollinger, H.;
Schnorrenberg, G.; Esser, F.; Engel, W.; Eberlein, W.;
Rudolf, K. Eur. J. Pharmacol. 1999, 384, R3.
12. Bonaventure, P.; Nepomuceno, D.; Mazur, C.; Lord, B.;
Rudolph, D. A.; Jablonowski, J. A.; Carruthers, N. I.;
Lovenberg, T. W. J. Pharmacol. Exp. Ther. 2004, in press.
13. All compounds presented in this paper were characterized
A detailed biological evaluation of compound 60, also
known as JNJ-5207787, was undertaken due to its high
affinity forthe NPY Y
receptor. JNJ-5207787 was
2
demonstrated to be an antagonist via inhibition of PYY-
stimulated [35S]GTPgS binding (pIC50 corr=7.2ꢁ0.12).12
This compound was also found to be >100-fold selec-
tive versus human Y1, Y4 and Y5 receptors as evaluated
by radioligand binding.12 In addition, JNJ-5207787 was
found to be selective against a wide variety of receptors
and enzymes (inhibition <50% at 1 mM).
1
by H NMR and MS.
14. Kitagawa, T.; Arita, J.; Nagahata, A. Chem. Pharm. Bull.
1994, 42, 1655.
15. IC50 values are the mean of two to six determinations12
(unless noted otherwise) followed by the SEM, given in
parentheses.
16. Karp, G. M.; Condon, M. E. J. Heterocycl. Chem. 1994,
31, 1513.
17. Bouzard, D.; DiCesare, P.; Essiz, M.; Jacquet, J. P.;
Ledoussal, B.; Remuzon, P.; Kessler, R. E.; Fung-Tomc,
J. J. Med. Chem. 1992, 35, 518.
18. Still, W. C.; Gennari, C. Tetrahedron Lett. 1983, 24, 4405.
19. During the preparation of the current manuscript, the first
description of small molecule NPY Y2 ligands appeared
without comment on theirfunctional activity. Anders,
C. J.; Zimanyi, I. A.; Deshpande, M. S.; Iben, L. G.;
Grant-Young, K.; Mattson, G. K.; Zhai, W. Bioorg. Med.
Chem. Lett. 2003, 13, 2883.
In conclusion, through an HTS effort a series of indo-
lylpiperidines, exemplified by 1 were identified as
potential NPY Y2 ligands. Through a medicinal chem-
istry program, we prepared compounds with 40-fold
higheraffinity forthe erceptor(
60, JNJ-5207787,
IC50=0.1 mM). Further biological evaluation of this
compound determined that it behaved as a selective
NPY Y2 antagonist. Thus, we have identified the first
small molecule NPY Y2 antagonist.19