N-((8-Hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-phenyloxy/amino-acetamide inhibitors of ADAMTS-5 (Aggrecanase-2)

Article abstract of DOI:10.1016/j.bmcl.2008.10.065

N-((8-Hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-phenyloxy/amino-acetamide inhibitors of ADAMTS-5 (Aggrecanase-2) have been prepared. Selected compounds 10, 14, 25, and 53 show sub-μM ADAMTS-5 potency and good selectivity over the related metal

Full text of DOI:10.1016/j.bmcl.2008.10.065

Bioorganic & Medicinal Chemistry Letters 18 (2008) 6454–6457
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
N-((8-Hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-phenyloxy/
amino-acetamide inhibitors of ADAMTS-5 (Aggrecanase-2)
a
a
b
b
Adam M. Gilbert a, , Matthew G. Bursavich , Sabrina Lombardi , Katy E. Georgiadis , Erica Reifenberg ,
*
Carl R. Flannery b, Elisabeth A. Morris b
a Exploratory Medicinal Chemistry, Chemical and Screening Sciences, Wyeth Research, 401 North Middletown Road, Pearl River, NY 10965, USA
b Women’s Health and Musculoskeletal Biology, Wyeth Research, 200 Cambridge Park Drive, Cambridge, MA 02140, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
N-((8-Hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-phenyloxy/amino-acetamide inhibitors
of ADAMTS-5 (Aggrecanase-2) have been prepared. Selected compounds 10, 14, 25, and 53 show
sub-lM ADAMTS-5 potency and good selectivity over the related metalloproteases ADAMTS-4 (Aggre-
canase-1), MMP-13, and MMP-12. Compound 53 shows a good balance of potent ADAMTS-5 inhibition,
moderate CYP3A4 inhibition and good rat liver microsome stability. This series of compounds represents
progress towards selective ADAMTS-5 inhibitors as disease modifying osteoarthritis agents.
Ó 2008 Elsevier Ltd. All rights reserved.
Received 5 September 2008
Revised 14 October 2008
Accepted 15 October 2008
Available online 18 October 2008
Keywords:
ADAMTS-5
ADAMTS-4
Aggrecanase-2
Aggrecanase-1
Osteoarthritis
Metalloproteases
Osteoarthritis (OA), the most common of musculoskeletal dis-
eases, is rapidly becoming a significant medical and financial bur-
den.1 This debilitating disease is caused by degradation of aggrecan
and collagen in the articular cartilage matrix leading to progressive
and chronic joint pain and inflammation. Aggrecan is a multido-
main proteoglycan that provides the elasticity and compressive
resistance to the articular cartilage that is lost in the initial phases
of OA. This loss of aggrecan fragments via proteolysis is attribut-
able to Aggrecanase activity.2 If this degradation is not halted or re-
versed, the cartilage will be subject to further breakdown by
additional metalloproteases resulting in irreversible damage to
the joint. While current OA treatments provide only symptomatic
relief (NSAIDs, intra-articular injections of hyaluronic acid conju-
gates, and surgical joint replacement), there is no therapy available
to halt and/or reverse the progression of this debilitating disease.3
Aggrecanases are members of the ADAMTS (A Disintegrin and
Metalloprotease with Thrombospondin Motifs) family of zinc
metalloproteases. Both ADAMTS-4 (Aggrecanase-1) and ADAMTS-
5 (Aggrecanase-2) cleave aggrecan at the Glu373–Ala374 peptide
bond.2 Recent studies have demonstrated reduced OA severity for
ADAMTS-5 knockout mice in a surgically induced instability mod-
el.4 ADAMTS-5 has also been shown to be the major ADAMTS in a
mouse model of inflammatory arthritis.5 Thus, the inhibition of
ADAMTS-5 may therefore protect cartilage from damage and pro-
vide the first potential therapy to halt and/or reverse the progres-
sion of OA.
Recently we reported a series of low-
lM rhodanines and selec-
tive, sub-
l
M thiadiazole inhibitors of ADAMTS-5.6–8 In this letter,
we report our initial studies on a series of ADAMTS-5 inhibitors I
found via high throughput screening9 and show their potential util-
ity as selective ADAMTS-5 therapeutics to treat OA. Whereas several
metalloprotease scaffolds have been disclosed, to our knowledge the
compounds presented herein represent a new class of metallopro-
tease inhibitors based on the hydroxyquinoline scaffold.10
R1
R2
N
OH HN
X
R3
O
I
Initial efforts to explore the N-((8-hydroxy-5-substituted-quinolin-
7-yl)(phenyl)methyl)-2-phenyloxy/amino-acetamide scaffold began
with the development of a parallel synthesis via a Mannich reaction
as outlined in Scheme 1.11,12 Reaction of 2-phenoxyacetamide
* Corresponding author. Tel.: +1 845 602 4865; fax: +1 845 602 5561.
E-mail address: gilbera@wyeth.com (A.M. Gilbert).
0960-894X/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2008.10.065

A. M. Gilbert et al. / Bioorg. Med. Chem. Lett. 18 (2008) 6454–6457
6455
R1
Cl
Cl
R1
R2
O
R2
Cl
R2
Cl
a
a
b
N
N
N
40-
20-
40-80%
N
N
60%
35%
OH HN
1-21
OH HN
22
OH HN
23-44
OR3
OH
OH
O
O
O
Scheme 1. Reagents and conditions: (a) 2-phenoxyacetamide, aldehyde, 180 °C.
Scheme 2. Reagents and conditions: (a) 2-chloroacetamide, substituted benzalde-
hyde, 150 °C; (b) substituted phenol, NaH, DMF, 0 °C to room temperature.
Bromine appears to give the best ADAMTS-5 potency (17, IC50
:
with either commercially- or readily-available13 5-substituted 8-hy-
droxyquinolinesand varioussubstitutedbenzaldehydes affordedthe
desired target hydroxyquinolines 1–21 (Table 1).
0.62 M; 18, IC50: 0.80 M). Finally compounds where the 8-hy-
l
l
droxy quinoline was changed to an 8-methoxy quinoline show re-
duced ADAMTS-5 inhibition (data not shown).
That the 5-quinoline position (R1 substituent) plays a significant
role in ADAMTS-5 inhibitory activity is shown in compounds 1–4
Overall, the compounds in Table 1 show low to moderate
CYP3A4 inhibition14 (these analogs display low CYP2D6 and
CYP2C9 inhibition) and poor rat liver microsome (RLM) stability.15
The CYP inhibition does not fluctuate greatly over these com-
pounds; however the microsome stability does. Increasing rat liver
microsome stability is seen with compounds 13 (t1/2 = 16 min), 17
(t1/2 = 30 min) and 18 (t1/2 = 10 min).
(Table 1). Whereas compound 1 (R1 = H) shows low-
lM activity,
this potency was decreased twofold with the incorporation of a
5-fluoro substituent in 2. The potency could be improved with
the incorporation of a 5-nitro substituent in 3 and further in-
creased with a 5-chloro substituent to afford sub-lM ADAMTS-5
To explore additional diversity points on the most potent
ADAMTS-5 analogs, a parallel synthesis was developed to allow
variation of R3 substituents where R1 = Cl as outlined in Scheme
2.12 Mannich reaction of 2-chloroacetamide with 5-chloro 8-hy-
droxy quinoline and various substituted benzaldehydes affords
the desired alkylchloro intermediate hydroxyquinolines 22. Subse-
quent displacement of the chloride with various substituted phe-
nols is accomplished using NaH DMF to afford the desired target
hydroxyquinoline compounds 23–42 (Table 2).
inhibitor 4 (IC50: 0.78 M).
l
To follow up these initial results compounds 5–16, incorporat-
ing various R2 substituents, were prepared. ADAMTS-5 inhibition
data for these compounds demonstrates that R2 substitution plays
a role for activity as ADAMTS-5 potency varies ꢀ1 log in these
compounds (Table 1). Optimal R2 substituents are seen in 8
(R2 = 4-NO2 IC50: 0.46
NO2; IC50: 0.49
M) and 14 (R2 = 2-Cl; IC50: 0.35
ents that give less potent compounds are seen in 6 (R2 = 4-OMe;
IC50: 1.0
M), 12 (R2 = 2-Me; IC50: 1.85 M) and 16 (R2 = 2-CN:
IC50: 2.32
M). Variation of R1 to Br (17 and 18), NO2 (19), and
l
M), 9 (R2 = 3-F; IC50: 0.62
l
l
M), 10 (R2 = 3-
l
M). R2 substitu-
The compounds in Table 2 show that the substituent on the
phenol moiety (R3) plays a role in ADAMTS-5 inhibition as well
as modulating CYP3A4 inhibition and RLM stability. When R2 = 4-
l
l
l
Me (20 and 21) shows that these substituents are also tolerated.
Table 1
In vitro ADAMTS-5 inhibition Data for various R1 and R2 substituted N-((8-hydroxy-5-
substituted-quinolin-7-yl)(phenyl)methyl)-2-phenoxyacetamides.
Table 2
In vitro ADAMTS-5 inhibition data for various R2 and R3 substituted N-((8-hydroxy-5-
substituted-quinolin-7-yl)(phenyl)methyl)-2-phenoxyacetamides.
R1
R2
Cl
R2
N
N
OH HN
O
OH HN
R3
O
O
O
R1
R2
ADAMTS-5
CYP3A4 inhib.b
RLM t1/2
(min)
b
Compound
Compound R2
R3
ADAMTS-5 CYP3A4 inhib.b RLM t1/2
IC50
b
a
IC50
(
l
M)
(% at 30
lM)
a
(l
M)
(% at 30
lM)
(min)
1
H
H
2.28
4.84
1.35
0.78
0.76
1.0
56
22
20
5
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
4-OMe 3-Pyridyl
4-OMe (4-Me)Ph
4-OMe (4-OMe)Ph
4-OMe (3-NMe2)Ph
2.98
0.77
0.94
1.67
33
78
74
56
37
25
21
67
18
19
20
69
2
16
2
F
H
4
8
3
4
NO2
Cl
H
H
5
15
9
5
6
7
8
Cl
Cl
Cl
Cl
4-Me
4-OMe
4-Cl
4-NO2
3-F
45
54
38
13
57
26
24
10
37
43
38
26
38
33
35
33
55
4-OMe (4-NHCOMe)Ph 3.39
4-OMe (3-Me, 4-Cl)Ph
4-OMe (4-OPh)Ph
>10
>10
1.66
2.33
>10
>10
1.90
1.02
1.33
0.83
0.46
0.62
0.49
1.22
1.85
0.83
0.35
1.21
2.32
0.62
0.80
0.94
1.32
2.42
10
3-NO2
3-NO2
3-NO2
3-NO2
H
H
3-F
3-F
3-F
2-Cl
2-Cl
2-Cl
2-Cl
3-Pyridyl
30
30
9
Cl
(4-COMe)Ph
(3-Me, 4-Cl)Ph
(3,5-Cl)Ph
(4-Me)Ph
10
11
12
13
14
15
16
17
18
19
20
21
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Br
Br
NO2
Me
Me
3-NO2
2-F
6
5
2-Me
2-CF3
2-Cl
2-NO2
2-CN
3-NO2
2-Cl
2-Cl
3-NO2
2-Cl
16
(4-Cl)Ph
(3-NMe2)Ph
53
31
35
38
4
4
8
30
5
11
30
10
7
(4-NHCOMe)Ph 3.37
3-Pyridyl
>10
(3-NMe2)Ph
1.72
(4-NHCOMe)Ph 2.34
(3-Me, 4-Cl)Ph
(4-tBu) Ph
>10
>10
30
10
23
24
6
5
a
a
Values are means of 2 experiments, standard deviations are 10%.
Standard deviations are 10%.
Values are means of 2 experiments, standard deviations are 10%.
Standard deviations are 10%.
B
b

6456
A. M. Gilbert et al. / Bioorg. Med. Chem. Lett. 18 (2008) 6454–6457
Table 3
Cl
Cl
In vitro ADAMTS-5 inhibition data for various R2, R3 and X-heteroatom linker
R2
Cl
R2
X
N-((8-hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-2-benzyloxy/amino-
acetamides.
a
N
N
50-
Cl
OH HN
43-64
R3
70%
OH HN
22
R2
O
O
N
Scheme 3. Reagents and conditions: (a) substituted aniline, DIEA, DMF, 90 °C or
benzylamine/benzylalcohol, NaH, DMF, 0 °C to room temperature different R3
substituents demonstrate low-lM ADAMTS-5 activity.
OH HN
R3
X
O
b
OMe (23–29), several R3 substituents show potent ADAMTS-5
activity—especially 24 (R3 = (4-Me)Ph; IC50
0.77 M) and 25
Compound
X
R2
R3
ADAMTS-5 CYP3A4 inhib.b RLM t1/2
a
IC50
(
lM) (% at 30
lM)
(min)
:
l
(R3 = (4-OMe)Ph; IC50: 0.94
lM). Unfortunately both of these com-
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
NH 4-Me (4-COMe) Ph
NH 4-Me (4-CN) Ph
NH 4-Me (3-NMe2)Ph
NH 4-Me (3-Me, 4-Cl)Ph 1.58
NH 4-Me Bn
NMe 4-Me Ph
NMe 4-Me Bn
NH 3-NO2 (4-COMe)Ph
NH 3-NO2 (3-Me, 4-Cl)Ph 1.19
NH 3-NO2 (4-NHCOMe)Ph 2.77
1.12
1.01
1.93
45
29
37
12
29
20
30
27
17
8
42
20
14
32
41
32
11
36
34
16
45
46
4
5
5
pounds show a significant level of CYP3A4 inhibition. When R2 = 3-
NO2, various R3 substituents show reduced ADAMTS-5 inhibition.
When R2 = H (34, 35), low-
l
M ADAMTS-5 activity is seen (IC50
M, respectively). When R2 = 3-F, analogs 36 and
37 with R3 = (3-NMe2)Ph or (4-NHCOMe)Ph show low-
M activity
(IC50: 1.33, and 3.37 M, respectively). Conversely analog 38 with
R3 = 3-pyridyl shows minimal ADAMTS-5 activity IC50 > 10
M) de-
:
1.83
0.78
1.28
1.07
10
6
16
7
12
30
19
11
6
13
11
16
8
1.90, and 1.02
l
l
l
l
spite its moderate CYP3A4 inhibition and excellent RLM stability.
NMe 3-NO2 Ph
NMe 3-NO2 Bn
0.56
0.82
When R2 = 2-Cl, analogs 39 and 40 with R3 = (3-NMe2)Ph or (4-
NH 3-F
NH 3-F
NMe 3-F
NMe 3-F
NH 2-Cl
NH 2-Cl
NMe 2-Cl
NMe 2-Cl
(3-Me, 4-Cl)Ph 1.43
NHCOMe)Ph show low-lM activity (IC50: 1.72, and 2.34 lM,
Bn
Ph
Bn
1.70
1.25
1.44
respectively). Conversely analogs 41 and 42 with R3 = (3-Me, 4-
Cl)Ph or (4-tBu)Ph demonstrate minimal ADAMTS-5 activity
(3-Me, 4-Cl)Ph 1.48
(IC50s > 10 lM) despite showing moderate CYP3A4 inhibition and
good RLM stability.
Bn
Ph
Bn
1.89
0.99
1.31
0.70
0.83
7
6
5
21
24
To further investigate the substituted X-aryl moiety (I), the
alkylchloro intermediate 22 was reacted with several different
nucleophiles as outlined in Scheme 3.12 Displacement of the chlo-
ride in 22 with various commercial- or readily-available anilines,
and benzyl amines was accomplished using DIEA in DMF to afford
the desired target compounds 43–62. Displacement of the chloride
in 22 with benzyl alcohol was accomplished using NaH in DMF to
afford the target compounds 63 and 64.
O
O
4-Me Bn
3-F Bn
a
Values are means of 2 experiments, standard deviations are 10%.
Standard deviations are 10%.
b
From the synthesis of this focused array (43–64) it was appar-
ent that the substituted heteroatom linker (X = NH, NMe, or O)
combined with the R3 substituent plays a role in ADAMTS-5
inhibition (Table 3). When X = NH and R2 = 4-Me several analogs
Table 4
In vitro selectivity data for N-((8-hydroxy-5-substituted-quinolin-7-yl)(phenyl)-
methyl)-2-phenoxyacetamides.
Compound
ADAMTS-5
ADAMTS-4
MMP-13
MMP-12
IC50 (lM)
a
a
a
a
(43–47) with different R3 substituents demonstrate low-
lM
IC50
(
lM)
IC50
(lM)
IC50
(
lM)
ADAMTS-5 activity. Compounds 48 and 49 with X = NMe demon-
strate slightly improved ADAMTS-5 activity (IC50 0.78, and
1.28 M, respectively). Similarly analogs 50–52 with X = NH and
R2 = 3-NO2 having different R3 substituents show low
M ADAM-
TS-5 activity, but analogs 53 and 54 with X = NMe show improved
10
14
25
53
0.49
0.35
0.94
0.56
1.9
2.4
>50
>22
>200
>67
>200
>100
45% at 2.5
50% at 2.5
37% at 2.5
25
lM
lM
lM
:
l
l
a
Values are means of 2 experiments, standard deviations are 10%.
ADAMTS-5 inhibition (IC50: 0.56, and 0.82 lM, respectively). Ana-
logs with X = NH or NMe and R2 = 3-F (55–58) and analogs with
X = NH or NMe and R2 = 2-Cl (59–62) combined different R3 sub-
none of the analogs show appreciable activity against MMP-13.
These compounds were also tested for selectivity against MMP-12
and showed moderate to good selectivity.
In conclusion, we have presented a series of hydroxyquinoline
inhibitors of ADAMTS-5. This series of compounds has tractable
stituents demonstrate low-
63 and 64 possessing X = O, an R3 benzyl substituent, and an R2
substituent either 4-Me or 3-Cl show sub- M ADAMTS-5 activity
(IC50: 0.70, and 0.83 M, respectively). Overall the analogs in Table
lM ADAMTS-5 activity. Compounds
l
l
3 show reduced CYP3A4 inhibition especially compared to analogs
in Table 2. It is also gratifying to see that several compounds show
good ADAMTS-5 inhibition and moderate to good RLM stabilities
(t1/2 > 15 min). The reduced lipophilicity of the amide- analogs in
Table 3 may be responsible for this trend.
Given the suggestive mouse ADAMTS-5 knockout data discussed
above,4,5 we assessed ADAMTS-5/ADAMTS-4 selectivity for several
of the more potent hydroxyquinolines presented in this manuscript
(Table 4). Analogs 10, 14, 25, and 53 each show significant selectivity
over ADAMTS-4 with 25 and 53 demonstrating excellent selectivity
for ADAMTS-5. We also assessed selectivity against MMP-13, an-
other metalloprotease implicated in osteoarthritis. Once again 10,
14, 25, and 53 demonstrate excellent selectivity for ADAMTS-5 as
SAR with several analogs of sub-lM potency demonstrating func-
tional selectivity for ADAMTS-5 over ADAMTS-4, MMP-13 and
MMP-12. In addition compounds were identified that possess good
ADAMTS-5 inhibition, low CYP3A4 inhibition and moderate to
good RLM stability. The continued development of selective
ADAMTS-5 inhibitors is currently ongoing and will be reported in
due course.
Acknowledgments
We thank Dr. John Ellingboe for support of this work and Dr.
Jeremy I. Levin for useful discussions in preparation of this

A. M. Gilbert et al. / Bioorg. Med. Chem. Lett. 18 (2008) 6454–6457
6457
6. Bursavich, M. G.; Gilbert, A. M.; Lombardi, S.; Georgiadis, K. E.; Reifenberg, E.;
Flannery, C. R.; Morris, E. A. Bioorg. Med. Chem. Lett. 2007, 17, 1185.
7. Gilbert, A. M.; Bursavich, M. G.; Lombardi, S.; Georgiadis, K. E.; Reifenberg, E.;
Flannery, C. R.; Morris, E. A. Bioorg. Med. Chem. Lett. 2007, 17, 1189.
manuscript. We thank Dr. Kristina Cunningham for performing
fluorescence polarization binding to target studies.
8. Bursavich, M. G.; Gilbert, A. M.; Lombardi, S.; Georgiadis, K. E.; Reifenberg, E.;
Flannery, C. R.; Morris, E. A. Bioorg. Med. Chem. Lett. 2007, 17, 5630.
9. ADAMTS-5 activity was determined using a Fluorescence Resonance Energy
References and notes
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