CCR2 receptor antagonists: Optimization of biaryl sulfonamides to increase activity in whole blood

Article abstract of DOI:10.1016/j.bmcl.2011.10.038

A series of biarylsulfonamides was identified as hCCR2 receptor antagonist but suffered from high plasma protein binding resulting in a >100 fold shift in activity in a functional GTPγS assay run in tandem in the presence and absence of human serum albumin. Introduction of an aryl amide with ethylenediamine linker led to compounds with reduced shifts and improved activity in whole blood.

Full text of DOI:10.1016/j.bmcl.2011.10.038

Bioorganic & Medicinal Chemistry Letters 21 (2011) 7291–7294
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Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
CCR2 receptor antagonists: Optimization of biaryl sulfonamides to increase
activity in whole blood
Gren Z. Wang, Pamela A. Haile, Tom Daniel, Benjamin Belot, Andrew Q. Viet, Krista B. Goodman,
Deyou Sha, Sarah E. Dowdell, Norbert Varga, Xuan Hong, Subhas Chakravorty, Christine Webb,
Carla Cornejo, Alan Olzinski, Roberta Bernard, Christopher Evans, Amanda Emmons, Jacques Briand,
⇑
Chun-Wa Chung, Ruben Quek, Dennis Lee, Peter J. Gough, Clark A. Sehon
Pattern Recognition Receptors DPU, ImmunoInflammation Therapeutic Area Unit, GlaxoSmithKline, 1250 South Collegeville Road, PA 19426, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of biarylsulfonamides was identified as hCCR2 receptor antagonist but suffered from high plasma
Received 2 September 2011
Revised 7 October 2011
Accepted 11 October 2011
Available online 19 October 2011
protein binding resulting in a >100 fold shift in activity in a functional GTPcS assay run in tandem in the
presence and absence of human serum albumin. Introduction of an aryl amide with ethylenediamine lin-
ker led to compounds with reduced shifts and improved activity in whole blood.
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
CCR2 antagonists
MCP-1
Biaryl sulfonamides
HSA
CCR2 knock-in mouse
Thioglycolate induced peritonitis
The CCR2 chemokine receptor and its primary ligand, monocyte
chemoattractant protein-1 (MCP-1), play key roles in attracting
monocytes to sites of inflammation. At the site of an atheroscle-
rotic lesion MCP-1 is up- regulated and, upon binding of MCP-1
to the CCR2 receptor, a signaling transduction cascade occurs and
monocytes are recruited to the site of the lesion. The aggregation
of these immune cells eventually leads to the formation of foam
cells and the build-up of plaque on the arterial wall.1 Deletion of
CCR2 in apoE deficient mice, a murine model of human atheroscle-
rosis, resulted in significant protection from both macrophage
accumulation and atherosclerotic lesion formation in response to
a high-fat diet.2 Similar studies also showed that CCR2À/À mice
fed a regular chow diet were more resistant to the development
of atherosclerosis than wild-type mice.3 Therefore, an antagonist
for the CCR2 receptor was targeted as a potential treatment for ath-
erosclerosis.4 Additional therapeutic indications have also become
very attractive including rheumatoid arthritis5 and multiple sclero-
sis.6 A wealth of patents and peer-reviewed journal articles have
published in the past decade which describe the development of
small molecule CCR2 antagonists.7
In a previous report,8 a series of biarylsulfonamides CCR2 antag-
onists as exemplified by compound 1 were described (Table 1).
Although compound 1 displays promising activity in our primary
CCR2 GTPcS assay, there was a shift observed in the chemotaxis
(CTX) assay when human serum was increased from 0.1% to 1.0%
as shown in Table 1. Due to this loss in activity, our objective
was focused on improving the activity of the sulfonamide series
in the presence of human serum. To expedite compound evalua-
tion, a high throughput GTP
was developed as a surrogate for human serum and run in parallel
with the primary GTP S assay in the absence of HSA. This allowed
cS assay in the presence of 5% HSA
c
for rapid identification of compounds with reduced shifts in activ-
ity between the two assays. This approach was validated using
compound 1 as a standard and when tested in the CCR2 GTPcS as-
say in the presence of 5% HSA9,10 the activity of 1 dropped by ꢀ120
fold.
Our chemistry strategy was centered on modulating the polar-
ity and/or basicity of the biaryl sulfonamides to reduce the ob-
served shift in activity. Ultimately, the introduction of polar
groups to the left-hand side of the molecule led to a subseries of
ethylenediamine linked amides which had significantly reduced
shifts in the presence of HSA. Although ortho, meta, and para-sub-
stitution all showed improvement, para-substituted amides had
the highest activity in the primary assay with and without HSA
(Table 2).
⇑
Corresponding author.
E-mail address: clark.a.sehon@gsk.com (C.A. Sehon).
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.10.038

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G. Z. Wang et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7291–7294
Table 1
Biarylsulfonamide series identified as CCR2 antagonist
Compound Structure
CCR2 fKi (0%
HSA) nM
CCR2 fKi (5%
HSA) nM
Fold
shift
CTX %I @
CTX %I
Rat PK (2 mg/kg, po)
1
l
M(0.1% HS)
@1
lM(1% HS)
T1/2
Cl (mL/
min/kg)
Vdss (L/
F
(h)
kg)
(%)
O
S
O
Cl
Cl
HN
1
10
1259
126
72
50
2.3
4.3
0.34
75
O
N
N
Cl
Table 2
Shift was reduced in the presence of HSA with incorporation of amide
#
R
CCR2 fKi 0%
HSA
CCR2 fKi 5%
HSA
Fold
shift
#
R
CCR2 fKi 0%
HSA
CCR2 fKi 5%
HSA
Fold
shift
Cl
S
N
N
N
Cl
HN
HN
HN
2
13
20
1.5
6
100
1000
10
O
O
O
O
N
R
HN
O
HN
HN
3
4
5
13
40
79
63
5
7
8
9
200
794
631
2511
1585
2512
13
2
O
O
N
Cl
N
N
N
HN
HN
HN
251
1259
6
O
O
O
N
HN
HN
16
4
O
Table 3
CF3 improves activity in both GTP
c
S assay and human whole blood shape change assay
O
O
O
S
O
S
Cl
Cl
CF3
Cl
R1
R1
HN
HN
O
O
HN
X
HN
X
Cl
Cl
O
O
R1
X
Compound
CCR2 fKi (0% HSA)
WB shape change pA2
Compound
CCR2 fKi (0% HSA) (nM)
WB shape change pA2
C
N
10
2
63
13
5.5
5.8
11
12
10
3
6.2
6.4
N
Table 4
Optimization of the substitution on the benzene sulfonamide
was also explored in parallel. It was determined that the 4-chloro,
3-trifluoromethyl substitution was the optimal benzene sulfon-
amide. This group gave consistent boost in activity in both the pri-
mary assay in the absence of HSA as well as in our low throughput
human whole blood shape change assay11 as demonstrated by
compounds 11 and 12 (Table 3). Unfortunately, when compound
12 was progressed to rat PK studies, a significant loss in oral
absorption was observed (Table 4) when compared to the original
lead 1 (Table 1).
Pharmacokinetic13 profile of compounds 12 and 13
12
13
Rat (1 mg/kg iv/2 mg/kg
po)
Rat (1 mg/kg iv/1.5 mg/kg
po)
Cmax (ng/mL)
T1/2 (h)
Cl (mL/min/
kg)
Vdss (L/kg)
F (%)
624
0.9
39
652
3.9
17
1.9
10
2.7
37
Due to the minimal activity difference observed in whole blood
between the pyridyl and phenyl central cores (Table 3), we chose
to move forward with the phenyl core based on a more efficient
synthetic route to these compounds (Scheme 1).12 The core 2-F,
5-Cl nitro arenes and aromatic alcohols were coupled under basic
conditions. Reduction of the nitro group was then achieved using
either nickel chloride and sodium borohydride or transfer hydroge-
nation with ammonium formate. Standard DMAP/pyridine

G. Z. Wang et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7291–7294
7293
R2
NO2
R3
R2
NH2
R3
NO2
R3
(iv)
(ii) or (iii)
(i)
O
F
O
OH
R2
O
O
O
O
O
O
+
Cl
Cl
Cl
SO2Ar
Cl
R2
HN
SO2Ar
Cl
SO2Ar
Cl
R2
R2
HN
HN
(v)
O
(vi)
O
O
O
O
O
O
HO
N
H
R1
R3
R3
R3
NH2
R1
Scheme 1. Typical reagents and conditions. (i) DMF, K2CO3, 70 °C; (ii) NiCl2, NaBH4, MeOH; (iii) HCOONH4, Pd/C, DCM, 50 °C; (iv) ArSO2Cl, DMAP, Pyridine 95 °C; (v) LiOH,
MeOH/H2O (1:1), 30 °C; (vi) Amine, BOP, TEA, DCM.
Table 5
Optimization of 4-Cl, 3-CF3 benzenesulfonamide
O
S
O
S
O
O
CF3
Cl
CF3
Cl
R1
R1
HN
HN
O
O
HN
HN
R2
Cl
Cl
O
R2
O
R1
R2
Compound
CCR2 fKi (0% HSA) (nM)
WB shape change pA2
Compound
CCR2 fKi (0% HSA) (nM)
WB shape change pA2
H
Me
11
14
10
16
6.2
5.9
11
20
10
25
6.2
5.6
N
MeO
15
10
6.4
21
25
6.0
H
Me
16
17
2
8
6.3
6.4
16
22
2
8
6.3
6.3
N
MeO
18
4
6.4
13
6
6.6
N
H
19
63
5.4
F
F
100
90
80
70
60
50
40
30
20
10
0
Blood levels of 12 and 13 in Female C57Bl/6 mice
at 40 mg/kg oral dose
2100
1800
1500
1200
900
600
300
0
12
13
54%
56%
0
1
2
3
4
5
6
7
Time (hr)
Figure 2. Blood levels of compounds 12 and 13 in satellite mice of in vivo study
shown in Figure 1.
Vehicle
12
13
Compound #
which has improved oral absorption and lower clearance with a
longer half-life in comparison to compound 12 (Table 4). In addi-
tion, compound 13 is the most active biaryl sulfonamide tested
in the whole blood assay (Table 5). Finally, the incorporation of
the gem di-F into the pyrrolidine 19, resulted in both a loss of
activity in the primary assay as well as in human whole blood.
Two of the more promising compounds identified, 1214 and 13,15
were advanced into a thioglycolate induced peritonitis model in the
humanized CCR2 knock-in mouse.16 PK/PD predictions based on rat
PK suggested a dose of 40 mg/kg was needed to achieve an ꢀ80%
reduction in monocyte recruitment for 12 and 13. Surprisingly, the
exposure observed in the C57Bl/6 mouse did not correlate well with
that predicted from the rat PK. Assuming linearity, the expected
Figure 1. Effect on monocyte recruitment (40 mg/kg oral dose).
conditions proved to be optimal for coupling the resulting anilines
with sulfonyl chlorides. Hydrolysis using LiOH afforded carboxylic
acids which were then coupled with various amines under stan-
dard conditions to yield the desired amides.
With a convergent synthetic scheme in place, we were easily
able to investigate substitution around the central and left-hand
side phenyl rings to see what effect it may have on the activity
and PK of the series. We believed that substitution of either of
the phenyl rings may block a metabolic soft spot and/or change
the orientation of the biaryl ether which could impact solubility
and bioavailability. This led to the identification of compound 13

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G. Z. Wang et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7291–7294
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assay plus 5% HSA allowed for the rapid identification of com-
pounds with improved activities in the presence of HSA. Additional
optimization led to the identification of the 4-chloro, 3-trifluoro-
methylphenyl sulfonamides and the tethered amides which dis-
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and more importantly the whole blood assay. Significant reduc-
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alternative series’ which were progressed in parallel with im-
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10. 0.2% w/v HSA was used. That is equal to 5% of physiological concentration or 4%
in whole blood.
11. (a) This human whole blood shape change assay was developed to further
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confirm the reduced shift observed in the screening assays; (b) Human blood
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to stimulation with various concentrations of MCP-1 for 5 minutes. After
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concentration, and pA2 values calculated by comparison to a dose response
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