1910
R. A. Porter et al. / Bioorg. Med. Chem. Lett. 11 (2001) 1907–1910
Summary
resuspended in, Tyrode’s medium containing 2.5 mM probenecid
ꢀ
and 1% gelatine, before being incubated for 30 min at 37 C
with either buffer alone (control) or buffer containing test
compound (10 pM–10 mM). The fluorescence (lex=488 nm,
lEM=540 nm) was then monitored using a fluorometric ima-
ging plate reader (FLIPR; Molecular Devices, UK) before and
after the addition of orexin-A in the continued presence of the
test compound. Data analysis: responses were measured as
peak fluorescence intensity (FI) minus basal FI, and curve-fit-
ting and parameter estimation were carried out according to a
four parameter logistic model, and results are expressed as a
In this communication, SAR of the high throughput
screening hit 1 at the OX receptor has been outlined.
1
The importance of the quinoline nitrogen and the quin-
oline benzo-ring has been demonstrated. The presence
of a small hydrophobic pocket associated with the aryl
ring substituent is postulated. The urea is proposed to
bind to the receptor in the extended lowenergy ZZ
conformation. Selectivity has been enhanced by mod-
ifying both the indole and quinoline motifs of 1. Finally
by replacement of the quinoline by a 1,5-naphthyridine,
CNS penetration has been increased. The naphthyridine
SB-334867 possesses CNS penetration, excellent selec-
tivity over a range of other receptors and ion channels
and in vivo activity following ip dosing.
pK
For further details see refs 2 and 12.
. Bromidge, S. M.; Dabbs, S.; Davies, D. T.; Duckworth,
b
. Results are the mean of three separate determinations.
8
D. M.; Forbes, I. T.; Ham, P.; Jones, G. E.; King, F. D.;
Saunders, D. V.; Starr, S.; Thewlis, K. M.; Wyman, P. A.;
Blaney, F. E.; Naylor, C. B.; Bailey, F.; Blackburn, T. P.;
Holland, V.; Kennett, G. A.; Riley, G. J.; Wood, M. D. J.
Med. Chem. 1998, 41, 1598.
9
1
. Ferraro, M. B. THEOCHEM 2000, 528, 199.
0. Singha, N. C.; Sathyanarayana, D. N. J. Chem. Soc.,
References and Notes
Perkin Trans. 2 1997, 157.
1. Yamaguchi, K.; Shudo, K. J. Agric. Food Chem. 1991, 39,
793.
1
1
. Sakurai, T.; Amemiya, A.; Ishii, M.; Matsuzaki, I.; Che-
melli, R. M.; Tanaka, H.; Williams, S. C.; Richardson, J. A.;
Kozlowski, G. P.; Wilson, S.; Arch, J. R. S.; Buckingham,
R. E.; Haynes, A. C.; Carr, S. A.; Annan, R. S.; McNulty,
D. E.; Liu, W.-S.; Terrett, J. A.; Elshourbagy, N. A.; Bergsma,
D. J.; Yanagisawa, M. Cell 1998, 92, 573.
2. Smart, D.; Jerman, J. C.; Brough, S. J.; Rushton, S. L.;
Murdock, P. R.; Jewitt, F.; Elshourbagy, N. A.; Ellis, C. E.;
Middlemiss, D. N.; Brown, F. Br. J. Pharmacol. 1999, 128, 1.
12. Smart, D.; Sabido-David, C.; Brough, S. J.; Jewitt, F.;
Johns, A.; Porter, R. A.; Jerman, J. C. Br. J. Pharmacol. 2001,
132, 1179.
13. Duxon, M. S.; Stretton, J.; Starr, K.; Jones, D. N. C.;
Holland, V.; Riley, G.; Jerman, J.; Brough, S. J.; Smart, D.;
Johns, A.; Chan, W.; Porter, R. A.; Upton, N. Psycho-
pharmacology 2001, 153, 203.
14. Haynes, A. C.; Jackson, B.; Chapman, H.; Tadayyon, M.;
Johns, A.; Porter, R. A.; Arch, J. R. S. Regul. Pep. 2000, 96,
45.
3. Haynes, A. C.; Jackson, B.; Overend, P.; Buckingham,
R. E.; Wilson, S.; Tadayyon, M.; Arch, J. R. S. Peptides 1999,
2
0, 1099.
. Chen, C.-T.; Hwang, L.-L.; Chang, J.-K.; Dun, N. J. Am.
15. Adams, J. T.; Bradsher, C. K.; Breslow, D. S.; Amore,
S. T.; Hauser, C. R. J. Am. Chem. Soc. 1946, 68, 1317.
16. Radinov, R.; Haimova, M.; Simova, E. Synthesis 1986,
886.
4
J. Physiol. Regul. Integr. Comp. Physiol. 2000, 278, R692.
5
1
6
. Pu, S.; Jain, M. R.; Kalra, P. S.; Kalra, S. Regul. Pept.
998, 78, 133.
. Piper, D. C.; Upton, N.; Smith, M. I.; Hunter, A. J. Eur. J.
17. Characterisation of SB-334867 hydrochloride 1H NMR
6
(250 MHz, DMSO-d ) d 2.61 (3H, s), 7.32 (1H, dd, J=2 and
Neurosci. 2000, 12, 726.
. Screening protocol in brief : CHO cells stably expressing
OX1 receptors (CHO-OX ), were seeded (20,000 cells/well)
into black walled clear-base 96-well plates (Costar, UK) in
MEM-Alpha medium and cultured overnight. Cells were
loaded with the cytoplasmic calcium indicator, Fluo-3AM
9 Hz), 7.65 (1H, d, J=9 Hz), 8.08 (1H, d, J=2 Hz), 8.17 (1H,
dd, J=4 and 9 Hz), 8.67 (1H, dd, J=1 and 10 Hz), 8.77 (1H,
d, J=7 Hz), 9.09 (1H, d, J=7 Hz), 9.22 (1H, dd, J=1 and
4 Hz), 10.80 (1H, s), 10.92 (1H, s). LC–MS (ES , TFA/
2 13 5 2
MeCN/H O variable gradient) calcd for C17H N O +H 320,
found 320 (100%).
7
1
+
(4 mM; Teflabs, Austin, TX, USA) in the presence of 2.5 mM
probenecid, and then washed four times with, and finally
18. Johns, A.; Porter R. A. Patent WO 9909024-A1, 1999.
19. Johns, A.; Porter R. A. Patent WO 9958533-A1, 1999.