Conversion of systemically-distributed triazole-based stearoyl-CoA desaturase (SCD) uHTS hits into liver-targeted SCD inhibitors

Article abstract of DOI:10.1016/j.bmcl.2011.08.073

It has been demonstrated that once-a-day dosing of systemically-distributed SCD inhibitors leads to adverse events in eye and skin. Herein, we describe our efforts to convert a novel class of systemically-distributed potent triazole-based uHTS hits into liver-targeted SCD inhibitors as a means to circumvent chronic toxicity.

Full text of DOI:10.1016/j.bmcl.2011.08.073

Bioorganic & Medicinal Chemistry Letters 21 (2011) 6505–6509
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Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Conversion of systemically-distributed triazole-based stearoyl-CoA
desaturase (SCD) uHTS hits into liver-targeted SCD inhibitors
Jean-Philippe Leclerc a, , Jean-Pierre Falgueyret b, Mélina Girardin c, Jocelyne Guay b, Sébastien Guiral b,
⇑
Zheng Huang b, Chun Sing Li a, Renata Oballa a, Yeeman K. Ramtohul a, Kathryn Skorey b, Paul Tawa b,
Hao Wang b, Lei Zhang b
a Department of Medicinal Chemistry, Merck Frosst Centre for Therapeutic Research, 16711 TransCanada Hwy, Kirkland, Quebec, Canada H9H 3L1
b Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, 16711 TransCanada Hwy, Kirkland, Quebec, Canada H9H 3L1
c Department of Process Research, Merck Frosst Centre for Therapeutic Research, 16711 TransCanada Hwy, Kirkland, Quebec, Canada H9H 3L1
a r t i c l e i n f o
a b s t r a c t
Article history:
It has been demonstrated that once-a-day dosing of systemically-distributed SCD inhibitors leads to
adverse events in eye and skin. Herein, we describe our efforts to convert a novel class of systemically-dis-
tributed potent triazole-based uHTS hits into liver-targeted SCD inhibitors as a means to circumvent
chronic toxicity.
Received 21 June 2011
Revised 11 August 2011
Accepted 15 August 2011
Available online 25 August 2011
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Stearoyl-CoA desaturase inhibitors
SCD inhibitors
Triazoles
Liver-targeted
MK-8245
Obesity and type II diabetes are two major health issues affect-
ing predominantly western countries. New medicines targeting
novel mechanism that may show advantages over existing medica-
tions are urgently needed.1 Stearoyl-CoA desaturase (SCD) is an
important enzyme involved in the lipogenic pathway. SCD, also
inhibitors devoid of eye and skin adverse events, the SAR and opti-
mization of a structurally diverse series of SCD inhibitors are de-
scribed herein.
Several groups have reported a number of different small-mole-
cules for the inhibition of the SCD enzyme.8,9 To identify novel and
new structurally distinct inhibitors in this area, an ultra high
throughput screening (uHTS) campaign was undertaken.10 Overall,
24 promising compounds were identified with IC50 values <300 nM.
In particular, a class of structurally distinct potent triazole SCD
inhibitors, as illustrated by 3 and 4 with IC50 values of 6 nM and
12 nM, respectively, were identified ( Fig. 2). Structure activity
explorations began with removal of the free amino group in 3, lead-
ing to compound 5, which is equipotent to the parent compound in
the rat microsomal assay (rSCD enzyme).11 For synthetic simplicity,
further SAR studies were focused on the des-amino triazole moiety.
known as delta-9 desaturase (
tion of saturated long-chain fatty acids into monounsaturated fatty
acids at their 9 position. More precisely, the favored SCD sub-
D9D), catalyzes the initial desatura-
D
strates are stearoyl-CoA and palmitoyl-CoA which are converted
into oleoyl-CoA and palmitoleoyl-CoA, respectively.2 These mono-
saturated fatty acids are the major components of various lipids
such as phospholipids, triglycerides, cholesterol ester and wax es-
ters.3 Recent studies in rodents have shown that inhibition, muta-
tion or deletion of SCD has a direct effect on fat utilization and
storage, which results in insulin sensitivity improvement, resis-
tance to diet-induced obesity, reduction of adiposity and plasma
triglycerides levels.4 Therefore, SCD represents an attractive new
target which could lead to the discovery of novel treatments for
obesity, type-2 diabetes and related metabolic disorders.5
O
O
S
N
H2N
Me
S
N
N
N
CF3
We recently have disclosed the discovery of MF-1526 and
MF-4387 ( Fig. 1) for assay development and proof-of-concept
studies in rodents. As part of our continued efforts to identify SCD
CF3
N
O
N
N
N
1 (MF-152)
rSCD IC50: 100 nM
2 (MF-438)
rSCD IC50: 2 nM
⇑
Corresponding author.
E-mail address: j.philippe.leclerc@gmail.com (J.-P. Leclerc).
Figure 1. MF-152 and MF-438 for assay development and rodent proof-of-concept
studies.
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.08.073

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J.-P. Leclerc et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6505–6509
Systemically-distributed
SCD inhibitor
uHTS hits
H2N
Liver / Harderian glands ratio: 0.4x
Liver / Skin ratio: 3.6x
8.00
6.00
4.00
2.00
0.00
O
O
X
X
Br
Br
N
N
N
N
H2N
H2N
N
N
X
Br
rSCD IC50
6 nM
12 nM
rSCD IC50
3 X = Br
4 X = Cl
5
19 nM
Br
Br
Liver-targeting
moiety
N
N
N
Plasma
0.74
Liver
2.69
Harderian glands
6.63
Skin
0.74
Br
Liver-targeting SCD inhibitor
uM
6
Tissue distribution of 5, 6h post oral dose at 10 mg/kg in 0.5%
methocel vehicle in C57/BL6 mice fed on a normal chow diet.
Figure 2. Strategy: Incorporation of a liver-targeting moiety on the systemic SCD inhibitor 5 derived from a uHTs campaign.
As expected, the tissue distribution profile of 5 (6 h post oral dose at
10 mg/kg in mouse) showed high exposures in many tissues and
therefore confirmed that 5 was, indeed, systemically-distributed (
Fig. 2).
As reported previously with MF-152 and MF-438, systemically
distributed compounds lead to the development of partial eye clo-
sure and progressive alopecia after ꢀ7–14 days of drug treatment
in rodents.6,7 We believed that SCD inhibition in the eye-lubricat-
ing Harderian glands and skin leads to reduced levels of SCD-de-
rived lipids present in the tears and skin/sebaceous glands which
may be essential for eye lubrication and healthy skin. Therefore,
we initially hypothesized that selectively targeting the liver (where
the SCD enzyme is mainly expressed), would lead to efficient
inhibitors with reduced eye and skin adverse events. Indeed, this
supposition was confirmed by the design of the liver-targeted
SCD inhibitor MK-8245.12 This compound is actively transported
inside the hepatocyte cells by the organic anion transporting poly-
peptides (OATPs)13 which can recognize a carboxylic acid residue
moiety present on the compound. Targeting OATPs favored the ac-
tive transport of the compound into the hepatocyctes over the
unselective passive cell diffusion. In light of these findings, we
sought to apply the same strategy to convert uHTS hits into li-
ver-targeted SCD inhibitors (Fig. 2).
Since the tetrazole acetic acid was believed to be the key moiety
responsible for liver-targeting, we directly replaced the primary
amide in 5 with this group. As show in Scheme 1,14 the triazole
n
Br
a, b, c
H2N
NO2
n
O
7
n
X
X
X
N
N
h
g
N3
H2N
N
X
O
X
Cl
d, e, f
X
HO
3
4
X = Cl, n = 1
X = Br, n = 1
9
X = Cl, n = 1
NH2
10 X = Br, n = 1
11 X = Br, n = 2
12 X = Br, n = 3
13 X = Br, n = 2
14 X = Br, n = 3
Cl
8
n
O
Br
Br
n
n
N
N
Br
Br
N
N
Br
Br
N
N
N
N
O
j, k, l
i
N
N
H2N
NC
N
N
N
HO
Br
Br
Br
5
n = 1
17 n = 1
18 n = 2
19 n = 3
20 n = 1
21 n = 2
22 n = 3
15 n = 2
16 n = 3
m
Br
Br
N
N
O
N
N
n, l
n
HO
N
Br
Br
HO
N
N
N
H2N
N
Br
O
24 n = 2
25 n = 3
26 n = 4
27 n = 5
Br
23
Scheme 1. Reagents and conditions: (a) Pd/C, H2, rt, 5 h; (b) Br2, CuBr2, MeCN, 50 °C, 1 h, then t-BuONO, 0.5 h; (c) NaN3, dimethyl formamide (DMF); (d) LiAlH4,
tetrahydrofurane (THF), 60 °C, 7 h; (e) t-BuONO, CuCl2, MeCN, rt, 2 h; (f) (PhO)2PN3, DBU, toluene, rt, 3 h; (g) H2NC(O)CH2CN, NaOH, EtOH, 85 °C, 3 h; (h) t-BuONO, THF, 50 °C,
2 h; (i) TFAA, triethylamine (TEA), dichlormethane (DCM), rt, 2 h; (j) NaN3, NH4Cl, DMF, 105 °C, 2 h; (k) ethyl2-bromoacetate, TEA, THF, reflux, 2 h; (l) NaOH, THF, MeOH, rt,
3 h; (m) NH2OHÁHCl, K2CO3, EtOH, rt, 16 h; (n) EtOC(O)CH2(CH2)nC(O)Cl, pyridine, 90 °C, 20 h.

J.-P. Leclerc et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6505–6509
6507
core was prepared via a [3+2] cycloaddition between azides 1015
and 2-cyanoacetamide. Following removal of the NH2 group with
tert-butyl nitrite, the amide was dehydrated with TFAA to generate
nitrile 17. Next, the nitrile was reacted with sodium azide to afford
the corresponding tetrazole, which after alkylation with ethyl bro-
moacetate, separation of the regioisomers16 and hydrolysis of the
ester led to desired compound 20. Unfortunately, this modification
resulted in a significant lost of SCD inhibitory activity (Table 1).
Based on our previous inhibitors, which contain a piperazine or
piperidine ring between the phenyl group and the heterocycle core
(Fig. 1), we believed that 20 may be too short in length.
To this end, we decided to vary the number of carbons at the
benzylic position. Syntheses of analogues 21 and 22, using the
appropriate benzyl bromide,17 are show in Scheme 1. The rSCD
data demonstrated that increasing the number of carbons at the
benzylic position from 1 to 3 gave a modest improvement in the
enzyme activity (Table 1).
Table 1
Effect on linker’s length
Compound
Structures
SCD IC50 (nM)
Rat microsomala
H2N
N
3
4
X = Br
X = Cl
6
12
O
X
N
N
H2N
X
X
O
Br
N
N
5
H2N
19
N
Br
Br
n
20
21
22
n = 1
n = 2
n = 3
>20,000
19,900
N
N
N
Br
Br
O
O
N
911
N
N
HO
HO
N
Br
Br
N
Br
Br
24
25
26
27
n = 2
n = 3
n = 4
n = 5
552
216
5246
8319
O
Next, we explored different acetic acid chain lengths. To sim-
plify the chemistry and avoid the difficult separation of the regioi-
somers generated in the alkylation step, we replaced the tetrazole
heterocycle by an oxadiazole ring, which was previously found to
be equipotent and a good replacement for the tetrazole moiety.18
In addition, oxadiazole-acid inhibitors have demonstrated liver-
N
N
N
N
n
a
IC50s are an average of at least two independent titrations.
Route to 6-membered ring heterocyclic linker
Br
N3
Br
10
6-membered
Br
NC
ring linker
Path A
c
29
X
X
N
N
X
X
N
N
6-membered
ring linker
O
N
N
e, f, g
6-membered
N
N
NC
a, b
ring linker
N
N
HO
31
32 to 37
X
X
X = Br or Cl
d
6-membered
ring linker
Path B
NC
X
Cl
N
Bu3Sn
N
28
N
Cl
Cl
30
Route to 5-membered ring heterocyclic linker
O
O
O
Br
Br
Br
Br
h, i
S
j, m
O
N3
N
N
S
O
Br
H
N
N
N
Br
Br
38
39
40
10
Cl
N3
Thiazole route
j
n, o, p
Isoxazole route
Cl
Cl
9
O
O
X
X
5-membered
ring linker
N
N
X = Br or Cl
N
41
X
e, f, g
k, l
N
N
X
X
N
N
5-membered
ring linker
O
N
N
N
HO
42, 43
X
Scheme 2. Reagents and conditions: (a) ethynyl(trimethyl)silane, Pd(PPh3)4, CuI, DCM, TEA, 50 °C, 2 h; (b) TBAF, THF, rt, 30 min; (c)
sulfateÁ5H2O, THF, water, 60 °C, 16 h; (d) 30, Pd(PPh3)2Cl2, dioxane, reflux, 2.5 h; (e) NaN3, NH4Cl, DMF, 105 °C, 2 h; (f) ethyl 2-bromoacetate, TEA, THF, reflux, 2 h; (g) NaOH,
THF, MeOH, rt, 3 h; (h) ethynyl(trimethyl)silane, Pd(PPh3)4, CuI, DCM, TEA, 50 °C, 2 h; (i) TBAF, THF, rt, 30 min; (j)
L-ascorbic acid sodium salt, copper(II)
L
-ascorbic acid sodium salt, copper(II) sulfateÁ5H2O, THF,
water, 60 °C, 16 h; (k) NH3, MeOH, 65 °C, 16 h; (l) TFAA, TEA, DCM, rt, 2 h; (m) DIBAL-H, DCM, À78 °C, 3 h; (n) NH2OHÁHCl, Na2CO3, THF, rt, 16 h; (o) NCS, DMF, rt, 20 h; (p)
methyl propiolate, TEA, DMF, rt, 2.5 h.

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J.-P. Leclerc et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6505–6509
Table 2
Effect of heterocyclic linkers
synthesis. Following standard procedures, the nitrile group was
then converted into the tetrazole acetic acid to generate com-
pounds 32–37.
N
N
X
X
N
N
O
Heterocyclic
linker
N
N
Initially, we decided to explore different substituted diazines
(Table 2). However, modest activities were obtained, with IC50s
ranging from 1814 nM to 343 nM in the rSCD enzyme assay
(32–36). Interestingly, we were pleased to observe an improve-
ment in potency by changing the substitution angle pattern
and the nature of the linker to pyridine (37). With regards to
six-membered ring linkers, compound 37 showed the best result
in the rat microsomal assay with an IC50 of 56 nM. This promis-
ing inhibitor was further tested in the rat hepatocyte assay12 and
in the HepG2 whole cell assay.22 The more potent rat hepatocyte
result over HepG2 data obtained with 37 suggest an active role
N
HO
X
Compound
Heterocyclic linker
X
rSCDa (IC50, nM)
1814
32c
Cl
N
N
N
33b
Br
1250
N
N
34c
35c
36c
Cl
Cl
Cl
343
1314
719
N
of the OATPs and potentially
a liver-targeted compound
(Table 3).23
N
Indeed, mouse tissue distribution studies demonstrated good li-
ver/tissue selectivity for 37, in particular the liver-to-Harderian
gland ratio (>94-fold, Table 3). Unfortunately, the mouse liver
pharmacodynamic assay (mLPD)24 showed no significant inhibi-
tion of SCD at a 30 mg/kg dose. We hypothesize that the low expo-
N
37b
42
Br
Cl
Br
56
49
21
N
sure observed in the liver (0.9
activity.
lM) is responsible for this lack of
S
To address this issue, we decided to explore five-membered ring
heterocyclic linkers. Given the success obtained with a thiazole and
an isoxazole ring in our previous studies,6,12 compounds 42 and 43
were synthesized (Scheme 2).14 The thiazole analogue was ac-
cessed by building the triazole moiety on the alkyne 39 using a
[3+2] cycloaddition with intermediate 9. On the other hand, ana-
logue 43 was accessed by building the isoxazole core on triazole
intermediate 40 via a three steps synthesis using NH4OH, NCS
and methyl propiolate. Ester 41 was further converted to the de-
sired final products using similar procedures as described
previously.
The five-membered ring linker replacement maintained po-
tency in the rat microsomal compared to the six-membered ring
linker 37 (Table 3). Delightfully, 42 and 43 are liver-targeted with
excellent liver-to-Harderian glands ratios of 66- and 100-fold,
respectively, with compound 43 having the highest exposure in
the liver in the mLPD. Unfortunately, even with a drug exposure
N
43
O
N
a
IC50s are an average of at least two independent titrations.
Compounds were synthesis using path A in Scheme 2.
Compounds were synthesis using path B in Scheme 2.
b
c
selective properties similar to tetrazole acetic acid inhibitors. Com-
pounds 24–27 were synthesized from intermediate nitrile 17 in a
three steps procedure using the appropriate acylchlorides19 in
the cycloaddition reaction (Scheme 1). As shown in Table 1, the
optimum linker was obtained when a maximum of three carbons
separate the acetic acid from the oxadiazole, but only with a mod-
est improvement in potency.
Having observed that the length of the inhibitor has an effect on
potency, we decided to explore more rigid heterocycles while
keeping the tetrazole acetic acid and triazole moieties. We choose
to begin our investigations by examining different six-membered
ring linkers. As illustrated in Scheme 2, all the compounds from
this series were accessed using path A or B.14 In path A, the triazole
core was generated via a Sharpless [3+2] cycloaddition20 reaction
between azide 10 and functionalized alkynes 29. In path B, the pre-
formed triazole core 3021 and the corresponding heterocyclic rings
28 were coupled under Stille reaction conditions. The few number
of synthetic steps in this route allowed access to rapid analogue
of 8.4 lM, which is 40-fold above its rat hepatocyte potency, com-
pound 43 did not afford any significant inhibition in the mLPD at a
30 mg/kg dose. We have examined activity across species (mouse,
rat and human) for many SCD inhibitors and have found similar
potencies.12 Since IC50s for 43 are similar in mouse (10 nM) and
rat (21 nM), the lack of mLPD efficacy is not likely due to species
differences. Although we do not completely understand this lack
of efficacy, based on our experience with other liver-selective com-
pounds, we observed that compounds with rat hepatocyte IC50’s
<200 nM and HepG2 IC50’s <1000 nM are generally active in the
Table 3
Potency and efficacy of liver-targeted SCD inhibitors
Compound
In vitroa
Rat hepatocyte
nM
In vivo
Rat microsomal
HepG2
nM
Tissue distribution (10 mg/kg, 6 h po)
Mouse liver pharmacodynamic
[Liver] % inhibition at 30 mg/kg
nM
[Liver] (
2.7
lM)
Liver/Harderian glands ratio
5
19
56
10,106
760
0.4Â
>94Â
14
0.9
Not significant
4.1
Not significant
8.4
30%, Not significant
l
M 46%b
37
694
6308
>100,000
37749
0.47
0.33
1.66
lM
42
43
49
21
975
212
>66Â
lM
100x
lM
a
IC50s are an average of at least two independent titrations.
Dose at 10 mg/kg.
b

J.-P. Leclerc et al. / Bioorg. Med. Chem. Lett. 21 (2011) 6505–6509
6509
Yamada, M.; Watanabe, N.; Takagi, T.; Wakimoto, S.; Okuyama, R.; Konishi, M.;
Kurikawa, N.; Kono, K.; Osumi, J. Bioorg. Med. Chem. Lett. 2009, 19, 4159; (e)
Ramtohul, Y. K.; Black, C.; Chan, C.-C.; Crane, S.; Guay, J.; Guiral, S.; Huang, Z.;
Oballa, R.; Xu, L.-J.; Zhang, L.; Li, C. S. Bioorg. Med. Chem. Lett. 2010, 12, 23; (f)
Powell, D. A.; Ramtohul, Y. K.; Lebrun, M.-E.; Oballa, R.; Falgueyret, J.-P.; Guiral,
S.; Huang, Z.; Skorey, K.; Tawa, P.; Zhang, L. Bioorg. Med. Chem. Lett. 2010, 20,
6366; (g) ACS 240th, Boston, 2010.; (h) Isabel, E.; Powell, D. A.; Black, C.; Chan,
C.-C.; Crane, S.; Gordon, R.; Guay, J.; Guiral, S.; Huang, Z.; Robichaud, J.; Skorey,
K.; Tawa, P.; Xu, L.; Zhang, L.; Oballa, R. Bioorg. Med. Chem. Lett. 2011, 21, 479;
(i) Atkinson, K. A.; Beretta, E. E.; Brown, J. A.; Castrodad, M.; Chen, Y.; Cosgrove,
J. M.; Du, P.; Litchfield, J.; Makowski, M.; Martin, K.; McLellan, T. J.; Neagu, C.;
Perry, D. A.; Piotrowski, D. W.; Steppan, C. M.; Trilles, R. Bioorg. Med. Chem. Lett.
2011, 21, 1621.
Tissue distribution of 5 and 43 in Mice
P.O. 10 mg/kg in 0.5% Methocel, 6 hours after dosage
0.4x
6.6
6
Systemically-distributed
Liver-targeted SCD inhibitor
SCD inhibitor
O
HO
N
N
O
Br
Br
N
N
5.4
4.8
4.2
3.6
3
N
Br
Br
N
H2
N
N
N
N
O
Br
N
N
Br
5
43
2.4
1.8
1.2
0.6
0
9. (a) Five initial applications from Xenon (WO2005/011653 to WO 2005/011657)
were published on February 10, 2005. WO2008/074835 and WO2009/106991
were also published in 2008 and 2009 respectively. Representative one: Abreo,
M.; Chafeev, M.; Chakka, N.; Chowdhury, S.; Fu, J.-M.; Gschwend, H. W.;
Holladay, M. W.; Hou, D.; Kamboj, R.; Kodumuru, V.; Li, W.; Liu, S.; Raina, V.;
Sun, S.; Sun, S.; Sviridov, S.; Winther, M. D.; Zhang, Z. WO2005/011655.; (b)
Xenon/Novartis patent: Dales, N.; Zhang, Z. WO2008/024390.; (c) Three
patents from GSK in 2009: WO2009/016216, WO2009/060053 and WO2009/
060054. Representative one: Bouillot, A. M. J.; Laroze, A.; Trottet, L. WO2009/
060053.
100x
Plasma
Liver
Harderian glands
Figure 3. From systemic lead to liver-targeted inhibitor.
10. Our approach was based on a SPA technology and recombinant FLAG tag
human SCD-1. In the first screen of the sample collection, a binding assay was
used to identify novel chemical structures, as well as the design of selective
and potent human SCD-1 inhibitors. Over 1.6 Â 106 compounds were tested
mLPD. It is likely that compounds 42 and 43 are too shifted in the
HepG2 assay (IC50’s >100,000 nM and 37,749 nM, respectively).
In summary, during an uHTS campaign we identified a structur-
ally distinct class of potent SCD inhibitors. To avoid potential eye
and skin adverse events, we converted the systemically distributed
triazole-based compound 5 into liver-targeting inhibitors by the
incorporation of a tetrazole acetic acid moiety and a pyridine linker
(37). Further modifications of the middle ring linker allowed us to
modulate in vitro (increased potency) and in vivo (increased liver
exposure) properties and generated isoxazole 43, a potent liver-
selective SCD inhibitor (Fig. 3). Unfortunately, despite the good li-
ver-selectivity and drug exposure, no significant in vivo inhibition
was observed. Further studies are underway to identify more effi-
cient and potent liver-targeting inhibitors of SCD in the mLPD.
and 12109 were found to give >35% inhibition at 9 lM. After confirmation of
the potency (triplicate of the binding assay), compounds were filtered,
clustered and then tested in a rat microsomal assay using a 3 point titration.
Finally, the best compounds were retested in the same rat assay using a 10
point titration curve. For more details see Skorey, K. and co-worker, J. Biomol.
Screen. 2011, 16, 506.
11. For rat microsomal assay conditions, see: Li, C. S.; Ramtohul, Y.; Huang, Z.;
Lachance, N. WO2006/130986.
12. Oballa, R. M.; Belair, L.; Black, C.; Bleasby, K.; Chan, C. C.; Desroches, C.; Du, X.;
Gordon, R.; Guay, J.; Guiral, S.; Hafey, M. J.; Hamelin, E.; Huang, Z.; Kennedy, B.;
Lachance, N.; Landry, F.; Li, C. S.; Mancini, J.; Normandin, D.; Pocai, A.; Powell,
D.; Ramtohul, Y.; Skorey, K.; Sturkenboom, W.; Styhler, A.; Waddleton, D.;
Wang, H.; Wong, S.; Xu, L.; Zhang, L. J. Med. Chem. 2011, 54, 5082.
13. For a review on OATP transporters, see: Niemi, M. Pharmacogenomics 2007, 8,
787.
14. For detailed experimental procedures, see: Leclerc, J.-P.; Li, C. S.; Ramtohul, Y.
K. WO 2010/025553.
Acknowledgments
15. For detailed experimental procedures on the synthesis of azide 10, see:
Strassburg, R. W.; Gregg, R. A.; Walling, C. J. Am. Chem. Soc. 1947, 69, 2141.
16. N2-Tetrazole acetic acid substitution showed reduced activity over the N3-
tetrazole acetic acid regioisomer. The proper regiochemistry was confirmed by
evaluation of the structures through NMR experiments: gHMBC, 15N gHMBC
and 1D NOESY.
The authors thank Dan Sørensen for NMR spectroscopic
assistance on gHMBC, 15N gHMBC and 1D NOESY experiments
and Nicolas Lachance for his advice and suggestions.
17. For detailed experimental procedures on the synthesis of azides 11 and 12, see:
(a) Blankespoor, L. R.; DeVries, T.; Hansen, E.; Kallemeyn, M. J.; Klooster, M. A.;
Mulder, A. J.; Smart, P. R.; Vander Griend, A. D. J. Org. Chem. 2002, 67, 2677; (b)
Katzenellenbogen, A. J.; Robertson, D. W. J. Org. Chem. 1982, 47, 2387.
18. Unpublished results.
19. For detailed experimental procedures on acylchloride syntheses, see: (a)
Thompson, A.; Regourd, J.; Al-Sheikh Ali, A. J. Med. Chem. 2007, 50, 1528; (b)
Shiraishi, M.; Kato, K.; Terao, S.; Ashida, Y.; Terashita, Z.-I.; Kito, G. J. Med. Chem.
1989, 32, 2214.
References and notes
1. (a) Dobrzyn, P.; Dobrzyn, A. Expert Opin. Ther. Patents 2010, 20, 849; (b) Liu, G.
Expert Opin. Ther. Patents 2009, 19, 1169; (c) Kopelman, P. G. Nature 2000, 404,
635.
2. Enoch, H. G.; Catala, A.; Strittmatter, P. J. Biol. Chem. 1976, 251, 5095.
3. Ntambi, J. M. Prog. Lipid Res. 1995, 34, 139.
4. (a) Jiang, G.; Li, Z.; Liu, F.; Ellsworth, K.; Dallas-Yang, Q.; Wu, M.; Ronan, J.; Esau,
C.; Murphy, C.; Szalkowski, D.; Bergeron, R.; Doebber, T.; Zhang, B. B. J. Clin.
Invest. 2005, 115, 1030; (b) Miyazaki, M.; Flowers, M. T.; Sampath, H.; Chu, K.;
Otzelberger, C.; Liu, X.; Ntambi, J. M. Cell Metab. 2007, 6, 484; (c) Savransky, V.;
Jun, J.; Li, J.; Nanayakkara, A.; Fonti, S.; Moser, A. B.; Steele, K. E.; Schweitzer, M.
A.; Patil, S. P.; Bhanot, S.; Schwartz, A. R.; Polotsky, V. Y. Circ. Res. 2008, 103,
1173.
5. (a) Dobrzyn, A.; Ntambi, J. M. Prostaglandins Leukot. Essent. Fatty Acids 2005, 73,
35; (b) Dobrzyn, A.; Ntambi, J. M. Obes. Rev. 2005, 6, 169.
6. Li, C. S.; Belair, L.; Guay, J.; Murgasva, R.; Sturkenboom, W.; Ramtohul, Y. K.;
Zhang, L.; Huang, Z. Bioorg. Med. Chem. Lett. 2009, 19, 5214.
20. Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B. Angew. Chem., Int. Ed.
2002, 41, 2596.
21. Intermediate 30 was obtained from the reaction of azide 9 with ethynyltri-N-
butyltin in benzene at 80 °C for 5 h.
22. Zhang, L.; Ramtohul, Y.; Gagné, S.; Styhler, A.; Guay, J.; Huang, Z. J. Biomol.
Screen. 2010, 15, 169.
23. Active OATPs are present in the cells of the rat hepatocyte assay, as opposed to
the HepG2 whole cells which lack these active transporters. When compared
side by side, those two assays give a good indication of potential active drug
transport in the liver as compared to passive cell diffusion. As such, a liver-
targeted SCD inhibitor transported by the OATPs will have a more potent
hepatocyte IC50 values over HepG2 inhibition. Therefore, this can be use to
evaluate the potential liver-targeted nature of a compound before performing
pharmacokinetic studies.
7. Leger, S.; Black, C.; Deschenes, D.; Dolman, S.; Falgueyret, J.-P.; Gagnon, M.;
Guiral, S.; Huang, Z.; Guay, J.; Leblanc, Y.; Li, C.-S.; Masse, F.; Oballa, R.; Zhang, L.
Bioorg. Med. Chem. Lett. 2010, 20, 499.
8. (a) Xin, Z.; Zhao, H.; Serby, M. D.; Liu, B.; Liu, M.; Szczepankiewicz, B. G.; Nelson,
L. T.; Smith, H. T.; Suhar, T. S.; Janis, R. S.; Cao, N.; Camp, H. S.; Collins, C. A.;
Sham, H. L.; Surowy, T. K.; Liu, G. Bioorg. Med. Chem. Lett. 2008, 18, 4298; (b)
Winther, M. D. 2nd Annual Drug Development for Diabetes and Obesity,
London, UK, Jan 17–18, 2008.; (c) Koltun, D. O.; Vasilevich, N. I.; Parkhill, E. Q.;
Glushkov, A. I.; Zilbershtein, T. M.; Mayboroda, E. I.; Boze, M. A.; Cole, A. G.;
Henderson, I.; Zautke, N. A.; Brunn, S. A.; Chu, N.; Hao, J.; Mollova, N.; Leung, K.;
Chisholm, J. W.; Zablocki, J. Bioorg. Med. Chem. Lett. 2009, 19, 3050; (d) Uto, Y.;
Ogata, T.; Kiyotsuka, Y.; Miyazawa, Y.; Ueno, Y.; Kurata, H.; Deguchi, T.;
24. Mouse liver pharmacodynamic model (mLPD) is expressed in percentage (%)
inhibition and is used to assess the in vivo potency. In the mLPD experiment,
mice (male C57BL6) were fed on a high carbohydrate diet and the SCD activity
was indexed 3 h post oral dose of SCD inhibitors by following the conversion of
intravenously administered [1-14C]-stearic acid tracer to the SCD-derived
[1-14C]-oleic acid in liver lipids. The percentage (%) of inhibition of an SCD
inhibitor is calculated from the liver SCD activity index (ratio of 14C-oleic
acid/14C-stearic acid) from drug treated animals compared to a vehicle group.