3-Hydroxy-4-arylsulfonyltetrahydropyranyl-3-hydroxamic acids are novel inhibitors of MMP-13 and aggrecanase

Article abstract of DOI:10.1016/j.bmcl.2004.06.081

N-Hydroxy-3-hydroxy-4-arylsulfonyltetrahydropyranyl-3-carboxamides were designed as novel inhibitors of MMP-13 and aggrecanase based on known endocyclic hydroxamate inhibitors of matrix metalloproteinases. These compounds offer favorable physicochemical properties and low metabolic clearance. Synthesis and structure-activity relationships are reported. N-Hydroxy-3-hydroxy-4- arylsulfonyltetrahydropyranyl-3-carboxamides were designed as novel inhibitors of MMP-13 and aggrecanase based on known endocyclic hydroxamate inhibitors of matrix metalloproteinases. These compounds offer favorable physicochemical properties and low metabolic clearance. Synthesis and structure-activity relationships are reported.

Full text of DOI:10.1016/j.bmcl.2004.06.081

Bioorganic & Medicinal Chemistry Letters 14 (2004) 4727–4730
3-Hydroxy-4-arylsulfonyltetrahydropyranyl-3-hydroxamic
acids are novel inhibitors of MMP-13 and aggrecanase
Mark C. Noe,* Sheri L. Snow, Lilli A. Wolf-Gouveia, Peter G. Mitchell,
Lori Lopresti-Morrow, Lisa M. Reeves, Sue A. Yocum,
Jennifer L. Liras and Marcie Vaughn
Pfizer Global Research and Development, Groton Laboratories, Eastern Point Road, Groton, CT 06340, USA
Received 24 May 2004; accepted 23 June 2004
Available online 19 July 2004
Abstract—N-Hydroxy-3-hydroxy-4-arylsulfonyltetrahydropyranyl-3-carboxamides were designed as novel inhibitors of MMP-13
and aggrecanase based on known endocyclic hydroxamate inhibitors of matrix metalloproteinases. These compounds offer favora-
ble physicochemical properties and low metabolic clearance. Synthesis and structure–activity relationships are reported.
ꢀ 2004 Elsevier Ltd. All rights reserved.
Osteoarthritis is a disease of progressive cartilage degra-
dation that leads to pain and reduced mobility in af-
fected joints. The pathogenesis of osteoarthritis can be
traced to multiple factors that lead to degeneration of
proteoglycan, and disruption of the type II collagen net-
work in cartilage. These two cartilage components main-
tain the tissueÕs structural integrity and impart critical
biomechanical properties necessary for the normal func-
tion of articulating joints. The aggregating proteogly-
can, aggrecan is composed of two N-terminal globular
domains that are separated by an interglobular domain,
followed by a glycosaminoglycan attachment region and
a C-terminal globular domain. Aggrecan monomers
interact with hyaluronic acid and link proteins to form
a heavily hydrated high molecular weight aggregate that
imparts resistance to compression. Type II collagen is a
triple-helical protein, which forms a highly organized
three-dimensional structure that is responsible for tissue
stiffness and resistance to shear forces. Because incorpo-
ration of functional type II collagen is not an active
process in adult cartilage, the loss of type II collagen
is considered to be an irreversible process in osteoarthri-
tis.1 Both aggrecan and type II collagen are degraded by
proteolytic enzymes that have elevated activity in osteo-
arthritic joints. ÔAggrecanasesÕ are defined by their func-
tional activity in cleaving aggrecan at specific sites in the
aggrecan protein backbone. Two members of the
ADAMTS (a disintegrin and metalloprotease possessing
thrombospondin domains) family, ADAMTS-42 and
ADAMTS-5,3 are believed to be primarily responsible
for cartilage aggrecan degradation. Collagenases are
the principle enzymes that cleave type II collagen and
are members of the MMP (matrix metalloprotease) fam-
ily. MMP-13 is particularly efficient at cleaving type II
collagen, and its expression has been shown to be ele-
vated in osteoarthritic joints.4 In order to protect both
the aggrecan and type II collagen components of carti-
lage, we sought to discover compounds that possessed
inhibitory activity versus both MMP-13 and aggreca-
nase. Such compounds could serve as effective therapeu-
tic agents for the treatment of osteoarthritis.
*
Corresponding author. Tel.: +1-860-441-8825; fax: +1-860-715-
2467; e-mail: mark_c_noe@groton.pfizer.com
0960-894X/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2004.06.081

4728
M. C. Noe et al. / Bioorg. Med. Chem. Lett. 14 (2004) 4727–4730
ClOC
O
O
O
3
(DHQ)2PHAL
OMe
O
Ar
O
Ar
OH
K2OsO4, K3Fe(CN)6
K2CO3, t-BuOH-H2O
~90%, 97% ee
Et3N, DMAP
OH
OH
O
O
CH2Cl2, >99%
4
5
1. SOCl2, Et3N,
CH2Cl2
2. RuCl3, NaIO4,
CCl4, CH3CN, H2O,
77%
Ar = 4-Methoxyphenyl
SH
O
O
OH
1.
OH
OH
O
O
Ar
NaH,
DMF
X
1. Derivatizationa
O
Ar
O
S
O
O
O
S
O
O
2. K2CO3, MeOH, r.t.
2. CH3CO3H,
NaOAc, CH2Cl2
69% overall
O
O
S
O
O
X
7
R
8a - 8t
6
O
OH
OH
ONH2-HCl
1.
OH
HO
HO
HN
HO
O
TEMPO,
O
S
O
EDC, HOBT, CH2Cl2
O
O
O
S
NaOCl, NaClO2,
R
O
2. Pd(PPh3)4, Et3N-HCO2H,
CH3CN-H2O
CH3CN, pH 7.0
80%
O
S
R
O
30-50%
O
R
8a - 8t
9a - 9t
2a - 2t
Scheme 1. Synthesis of 3-hydroxy-4-arylsulfonyltetrahydropyranyl-3-hydroxamic acids from dihydropyranylmethanol. (a) Conditions for
R=OCH2Ar: X=OH, ArCH2Br, Cs2CO3, DMF, 23ꢁC, 4–12h; for R=OAr: X=OH, ArB(OH)2, Cu(OAc)2, Et3N, MS4A, CH2Cl2, O2, rt, 24h;
for R=Ar: X=Br, ArB(OH)2, Pd(OAc)2, Bu4NBr, K2CO3, toluene, reflux, 30min.
Previous MMP and TNF-a converting enzyme (TACE)
programs at Pfizer led to the discovery of pipecolic acid
based inhibitors such as 1.5 These compounds generally
lacked potent aggrecanase inhibition and suffered from
metabolic lability of the hydroxamic acid moiety. We
envisioned the series represented by 2 to be superior
due to increased polarity, steric encumbrance of the hy-
droxamic acid moiety and proximity of the polar hyd-
roxy group to the hydroxamate functionality.6
benzylic halides to form benzyl ether analogs, converted
to the corresponding aryl triflate and coupled with aryl
boronic acids under palladium catalysis to form biaryl-
sulfones, or reacted with arylboronic acids under cop-
per(II) catalysis in the presence of molecular oxygen to
form biaryl ether sulfones.9,10 Alkylation of the 3-hyd-
roxy group could be effected by treatment of the appro-
priate intermediate 7 with methyl iodide and silver
nitrate. Removal of the 4-methoxybenzoyl group, fol-
lowed by oxidation of the hydroxymethyl group using
sodium chlorite with catalytic TEMPO and sodium hyp-
ochlorite at neutral pH affords the carboxylic acid 9 in
80% yield.11 This intermediate was converted to the O-
allyl hydroxamate using standard peptide coupling
conditions, followed by removal of the allyl group with
triethylammonium formate under palladium catalysis to
afford the final compounds.12
The synthesis of the tetrahydropyranyl template that
was used for analog preparation is shown in Scheme 1.
The chiral centers are introduced through a highly
enantioselective asymmetric dihydroxylation of the
4-methoxybenzoate 4 using catalytic (DHQ)2PHAL
and potassium osmate under standard conditions.7
Reaction of the diol 5 with thionyl chloride followed
by oxidation with RuCl3 and NMO affords the cyclic
sulfate 6 in high yield.8 Upon treatment with 4-hydroxy-
thiophenol sodium salt in DMF at elevated temperature,
the cyclic sulfate opens at the less hindered position to
afford the arylsulfide in 93% yield. Oxidation of the sul-
fide with peracetic acid afforded the sulfone 7 in 74%
yield. At this point, the phenol could be alkylated with
Initial analog generation was focused around 4-benzyl-
oxy aryl sulfones that were prepared to probe struc-
ture–activity relationships about this group, which is
thought to bind in the S10 pocket by analogy with the
previously discovered pipecolic hydroxamate TACE
inhibitor 1. The biological data obtained for each of

M. C. Noe et al. / Bioorg. Med. Chem. Lett. 14 (2004) 4727–4730
4729
Table 1. Aggrecanase, MMP-13, and MMP-1 inhibitory activity of benzyl ether analogs 2a–n
Compounds
R
Aggrecanase IC50 (nM)
MMP-13 IC50 (nM)
MMP-1 IC50 (nM)
2a
2b
2c
2d
2e
2f
2-Methylbenzyloxy
3-Methylbenzyloxy
55
21
12,000
22,000
5400
>1000
>1000
40
5.0
1.3
2.7
2.4
0.88
28
4-Methylbenzyloxy
2-Chlorobenzyloxy
2800
7900
3-Chlorobenzyloxy
4-Chlorobenzyloxy
>1000
330
220
1400
2g
2h
2i
2-Trifluoromethylbenzyloxy
2,3-Dichlorobenzyloxy
2,4-Dichlorobenzyloxy
2,5-Dichlorobenzyloxy
2,6-Dichlorobenzyloxy
2,4-Dimethylbenzyloxy
2,5-Dimethylbenzyloxy
2,6-Dimethylbenzyloxy
>30,000
13,000
920
140
8.1
15
0.95
13
2j
87
27,000
>30,000
19,000
>30,000
>30,000
2k
2l
>1000
370
26
>300
17
2m
2n
300
>300
>1000
these compounds is shown in Table 1.13 Electron rich
groups were avoided in an effort to optimize metabolic
stability of the benzyl ether. Aggrecanase potency is
strongly dependent on the presence of an ortho substit-
uent on the terminal aromatic ring. Generally chloro
substituted analogs possess better potency versus both
MMP-13 and aggrecanase compared with their methyl
substituted counterparts (compare 2d with 2a, 2i with
2l, and 2j with 2m). This observation is fortuitous in that
the halo substituted compounds are expected to have
better metabolic stability due to the lack of an addi-
tional benzylic position that could be oxidatively labile.
Replacement of the ortho chloro or methyl substituent
with the bulkier trifluoromethyl group (2g) led to a
reduction in potency against both of these enzymes.
Optimum potency for aggrecanase inhibition is obtained
with one ortho substituent, but the presence of two ortho
substituents (2k,n) results in a dramatic reduction in
both aggrecanase and MMP-13 potency. The presence
of meta or para substituents generally provides an
improvement in MMP-13 potency. Each of these struc-
ture–activity relationships is additive across the two en-
zymes, and combination of an ortho and para chloro
substituent results in optimum dual inhibition of
MMP-13 and aggrecanase. All of the benzylic ether ana-
logs show poor MMP-1 inhibitory potency.
on the terminal aromatic ring results in a dramatic
reduction of MMP-13 and MMP-1 potency (2r).
In order to determine the importance of the 3-hydroxyl
group, the potency of several methyl ether analogs (10a–
b) was determined. Interestingly, this modification is
detrimental to potency for both MMP-13 and aggreca-
nase. These studies were only conducted on benzyl ether
analogs of 10, since the parent biaryl and biaryl ether
sulfone analogs of 2 that were tested demonstrated min-
imal activity versus aggrecanase (Table 4).
Compound 2i is a potent inhibitor of both MMP-13 and
aggrecanase. Other MMP inhibitory activity is summa-
rized below.
MMP
IC50 (nM)
2
12
3
55
9
5.3
12
0.95
14
150
Biological data for biaryl ether and biaryl analogs of 2
are shown in Tables 2 and 3, respectively. These com-
pounds are generally potent inhibitors of MMP-13 but
have dramatically reduced potency versus aggrecanase
compared to their benzyl ether counterparts. Moreover,
potency versus MMP-1 generally increases as the termi-
nal aryl group is moved closer to the central aromatic
ring. This is consistent with the shorter S10 pocket in
MMP-1 compared with many of the other MMPs.14
In the biaryl series, incorporation of an ortho substituent
The pharmacokinetic parameters of compound 2i in rat
show low clearance (Clp=9.0mL/min/kg), and a long
t1/2 (5h).15 Unfortunately, oral bioavailability was poor
(7% when dosed as a suspension in 0.5% aqueous meth-
ylcellulose) despite good Papp values obtained in CACO-
2 experiments (Papp A:B=30·10ꢀ6; B:A=15·10ꢀ6).
Table 2. Aggrecanase, MMP-13, and MMP-1 inhibitory activity of biaryl ether analogs 2o–q
Compounds
R
Aggrecanase IC50 (nM)
MMP-13 IC50 (nM)
MMP-1 IC50 (nM)
2o
2p
2q
2-Methylphenoxy
3-Methylphenoxy
4-Methylphenoxy
>1000
>1000
>1000
9.8
1.1
1.0
4700
270
120

4730
M. C. Noe et al. / Bioorg. Med. Chem. Lett. 14 (2004) 4727–4730
Table 3. Aggrecanase, MMP-13, and MMP-1 inhibitory activity of biaryl analogs 2r–t
Compounds
R
Aggrecanase IC50 (nM)
MMP-13 IC50 (nM)
MMP-1 IC50 (nM)
2r
2s
2t
2-Methylphenyl
3-Methylphenyl
4-Methylphenyl
>1000
>1000
>1000
140
10,000
<30
<30
0.43
0.39
Table 4. Aggrecanase and MMP-13 inhibitory activity of benzyl ether
analogs 10a–b
R.; Kamath, A. V.; Laird, E. R.; Lopresti-Morrow, L. L.;
McClure, K. F.; Mitchell, P. G.; Natarajan, V.; Noe, M.
C.; Pandit, J.; Reeves, L. M.; Schulte, G. K.; Snow, S. L.;
Sweeney, F. J.; Tan, D. H.; Yu, C. H. Bioorg. Med. Chem.
Lett. 2002, 12, 1387.
Compounds
R
Aggrecanase
IC50 (nM)
MMP-13
IC50 (nM)
10a
10b
2-Chlorophenyl
2,4-Dichlorophenyl
100
100
38
46
6. Venkatesan, A.; Davis, J. M.; Grosu, G. T.; Baker, J.;
Ellingboe, J.; Zask, A.; Levin, J. I.; Sandanayaka, V. P.;
Du, M.; Skotnicki, J.; DiJoseph, J. F.; Sung, A.; Sharr, M.
A.; Killar, L. M.; Walter, T.; Jin, G.; Cowling, R.; Tillett,
J.; Zhao, W.; McDevitt, J.; Xu, Z. B. J. Med. Chem. 2003,
46, 2376.
7. Kolb, H. C.; VanNieuwenhze, M. S.; Sharpless, K. B.
Chem. Rev. 1994, 94, 2483.
8. Byun, H.-S.; He, L.; Bittman, R. Tetrahedron 2000, 56,
7051.
We have discovered a novel series of MMP-inhibitors
structured around a 3-hydroxy-4-arylsulfone tetra-
hydropyranyl hydroxamate template. Despite the fact
that these compounds were designed based on analogy
with an earlier endocyclic hydroxamate series of TACE
inhibitors, we were unable to find any that potently in-
hibit this enzyme in human whole blood (IC50 > 100lM
in human whole blood assays for 2d–f). Several of these
inhibitors possess potent inhibitory activity versus ag-
grecanase and MMP-13 and could provide a useful
starting point for the discovery of agents for the treat-
ment of osteoarthritis.
9. Chan, D. M. T.; Monaco, K. L.; Wang, R.-P.; Winter, M.
P. Tetrahedron Lett. 1998, 39, 2933.
10. Evans, D. A.; Katz, J. L.; West, T. R. Tetrahedron Lett.
1998, 39, 2937.
11. Zhao, M.; Li, J.; Mano, E.; Song, Z.; Tschaen, D.;
Grabowski, E. J. J.; Reider, P. J. J. Org. Chem. 1999, 64,
2564.
1
12. All new compounds exhibited satisfactory H NMR and
MS analysis.
References and notes
13. TACE, MMP, and whole blood TNF-a release assays
were conducted as described in Ref. 5. Aggrecanase
activity was assessed using a cell based assay: porcine
chondrocytes were plated in 48-well tissue culture plates.
Glycosaminoglycan (GAG) chains were labeled by includ-
ing 35S sulfate (5mCi/mL) in the culture medium. Unin-
corporated label was washed out and aggrecan
degradation stimulated by the addition of IL-1a (5ng/
mL). 10h later, aggrecan degradation was quantified by
scintillation counting of 35S in both the conditioned
medium and cell layers.
1. Maroudas, A.; Palla, G. Connect. Tissue Res. 1992, 28,
161.
2. Tortorella, M. D.; Burn, T. C.; Pratta, M. A.; Abbaszade,
I.; Hollis, J. M.; Liu, R.; Rosenfeld, S. A.; Copeland, R.
A.; Decicco, C. P.; Wynn, R.; Rockwell, A.; Yang, F.;
Duke, J. L.; Solomon, K.; George, H.; Bruckner, R.;
Nagase, H.; Itoh, Y.; Ellis, D. M.; Ross, H.; Wiswall, B.
H.; Murphy, K.; Hillman, M. C.; Hollis, G. F.; Newton,
R. C.; Magolda, R. L.; Trzaskos, J. M.; Arner, E. C.
Science 1999, 284, 1664.
3. Abbaszade, I.; Liu, R.-Q.; Yang, F.; Rosenfeld, S. A.;
Ross, H.; Link, J. R.; Ellis, D. M.; Tortorella, M. D.;
Pratta, M. A.; Hollis, J. M.; Wynn, R.; Duke, J. L.;
George, H. J.; Hillman, M. C.; Murphy, K.; Wiswall, B.
H.; Copeland, R. A.; Decicco, C. P.; Bruckner, R.;
Nagase, H.; Itoh, Y.; Newton, R. C.; Magolda, R. L.;
Trzaskos, J. M.; Hollis, G. F.; Arner, E. C.; Burn, T. C. J.
Biol. Chem. 1999, 274, 23443.
14. Lovejoy, B.; Welch, A. R.; Carr, S.; Luong, C.; Broka, C.;
Hendricks, R. T.; Campbell, J. A.; Walker, K. A. M.;
Martin, R.; Van Wart, H.; Browner, M. F. Nat. Struct.
Biol. 1999, 6, 217.
15. Male Sprague-Dawley rats were obtained with jugular
vein catheters from Charles River Labs, Wilmington, MA.
I.V. bolus doses were administered in glycerol formal
(5mg/kg). Blood samples (600mL) were collected from the
jugular vein (t=5, 15, 30min, 1, 2, 4, 6, 8, and 24h).
Plasma was diluted with an equal volume of water
and extracted with MTBE. Drug levels were determined
by LC–MS/MS analysis. Pharmacokinetic parameters
were calculated using the noncompartmental method in
WINNONLIN v2.1 (Pharsight, Mountain View, CA).
4. Mitchell, P. G.; Magna, H. A.; Reeves, L. M.; Lopresti-
Morrow, L. L.; Yocum, S. A.; Rosner, P. J.; Geoghegan,
K. F.; Hambor, J. E. J. Clin. Invest. 1996, 97, 761.
5. Letavic, M. A.; Axt, M. Z.; Barberia, J. T.; Carty, T. J.;
Danley, D. E.; Geoghegan, K. F.; Halim, N. S.; Hoth, L.