Design, synthesis, and biological evaluation of (E)-3-(4-methanesulfonylphenyl)-2-(aryl)acrylic acids as dual inhibitors of cyclooxygenases and lipoxygenases

Article abstract of DOI:10.1016/j.bmc.2006.08.008

A group of (E)-3-(4-methanesulfonylphenyl)acrylic acids possessing a substituted-phenyl ring (4-H, 4-Br, 3-Br, 4-F, 4-OH, 4-OMe, 4-OAc, and 4-NHAc) attached to the acrylic acid C-2 position were prepared using a stereospecific Perkin condensation reaction. A related group of compounds having 4- and 3-(4-isopropyloxyphenyl)phenyl, 4- and 3-(2,4-difluorophenyl)phenyl and 4- and 3-(4-methanesulfonylphenyl)phenyl substituents attached to the acrylic acid C-2 position were also synthesized, using a palladium-catalyzed Suzuki cross-coupling reaction, for evaluation as dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors. (E)-2-(3-Bromophenyl)-3-(4-methanesulfonylphenyl)acrylic acid (9h), and compounds having 4-(4-isopropyloxyphenyl-, 2,4-difluorophenyl-, or 4-methylsulfonylphenyl)phenyl moieties at the acrylic acid C-2 position (11a,b,d), were particularly potent COX-2 inhibitors with a high COX-2 selectivity index (COX-2 IC₅₀ ≈ 0.32 μM, SI > 316) similar to the reference drug rofecoxib (COX-2 IC₅₀ = 0.5 μM, SI > 200). Acrylic acid analogs with a C-2 4-hydoxyphenyl (9d, IC₅₀ = 0.56 μM), or 4-acetamidophenyl (9g, IC₅₀ = 0.11 μM), substituent were particularly potent 5-LOX inhibitors that may participate in an additional specific hydrogen-bonding interaction. A number of compounds possessing a C-2 substituted-phenyl moiety (4-Br, 4-F, and 4-OH), or a 4- or 3-(2,4-difluorophenyl)phenyl moiety, showed potent 15-LOX inhibitory activity (IC₅₀ values in the 0.31-0.49 μM range) relative to the reference drug luteolin (IC₅₀ = 3.2 μM). Compounds having a C-2 4-acetylaminophenyl, or 4-(2,4-difluorophenyl)phenyl, moiety exhibited anti-inflammatory activities that were equipotent to aspirin, but less than that of celecoxib. The structure-activity data acquired indicate the acrylic acid moiety constitutes a suitable scaffold (template) to design novel acyclic dual inhibitors of the COX and LOX isozymes.

Full text of DOI:10.1016/j.bmc.2006.08.008

Bioorganic & Medicinal Chemistry 14 (2006) 7716–7727
Design, synthesis, and biological evaluation of
(E)-3-(4-methanesulfonylphenyl)-2-(aryl)acrylic acids as dual
inhibitors of cyclooxygenases and lipoxygenases
Anne Moreau, Qiao-Hong Chen, P. N. Praveen Rao and Edward E. Knaus*
Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alta., Canada T6G 2N8
Received 17 July 2006; revised 8 August 2006; accepted 8 August 2006
Available online 22 August 2006
Abstract—A group of (E)-3-(4-methanesulfonylphenyl)acrylic acids possessing a substituted-phenyl ring (4-H, 4-Br, 3-Br, 4-F, 4-
OH, 4-OMe, 4-OAc, and 4-NHAc) attached to the acrylic acid C-2 position were prepared using a stereospecific Perkin condensa-
tion reaction. A related group of compounds having 4- and 3-(4-isopropyloxyphenyl)phenyl, 4- and 3-(2,4-difluorophenyl)phenyl
and 4- and 3-(4-methanesulfonylphenyl)phenyl substituents attached to the acrylic acid C-2 position were also synthesized, using
a palladium-catalyzed Suzuki cross-coupling reaction, for evaluation as dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-
LOX) inhibitors. (E)-2-(3-Bromophenyl)-3-(4-methanesulfonylphenyl)acrylic acid (9h), and compounds having 4-(4-isopropyloxy-
phenyl-, 2,4-difluorophenyl-, or 4-methylsulfonylphenyl)phenyl moieties at the acrylic acid C-2 position (11a,b,d), were particularly
potent COX-2 inhibitors with a high COX-2 selectivity index (COX-2 IC50 ꢀ 0.32 lM, SI > 316) similar to the reference drug rofec-
oxib (COX-2 IC50 = 0.5 lM, SI > 200). Acrylic acid analogs with a C-2 4-hydoxyphenyl (9d, IC50 = 0.56 lM), or 4-acetamidophenyl
(9g, IC50 = 0.11 lM), substituent were particularly potent 5-LOX inhibitors that may participate in an additional specific hydrogen-
bonding interaction. A number of compounds possessing a C-2 substituted-phenyl moiety (4-Br, 4-F, and 4-OH), or a 4- or 3-(2,4-
difluorophenyl)phenyl moiety, showed potent 15-LOX inhibitory activity (IC50 values in the 0.31–0.49 lM range) relative to the
reference drug luteolin (IC50 = 3.2 lM). Compounds having a C-2 4-acetylaminophenyl, or 4-(2,4-difluorophenyl)phenyl, moiety
exhibited anti-inflammatory activities that were equipotent to aspirin, but less than that of celecoxib. The structure–activity data
acquired indicate the acrylic acid moiety constitutes a suitable scaffold (template) to design novel acyclic dual inhibitors of the
COX and LOX isozymes.
ꢀ 2006 Elsevier Ltd. All rights reserved.
1. Introduction
and 15-LOX isozymes similarly catalyze the transforma-
tion of AA to 8-HPETE, 12-HPTE, and 15-HPTE,
respectively.1 PGs and LTs produced in these COX
and LOX pathways have been implicated as pro-inflam-
matory mediators in numerous inflammatory diseases,
in allergic disorders,2 in cell proliferation, and in neoan-
giogenesis.3 Moreover, LTs are involved in the etiology
of atherosclerosis.4
Arachidonic acid (AA), following its release from mem-
brane-bound phospholipids, undergoes biotransforma-
tion via the cyclooxygenase (COX) and lipoxygenase
(LOX) pathways. In the COX pathway, the COX-1,
COX-2, and COX-3 isoforms convert AA to the hydro-
xy-endoperoxide PGH2 which is subsequently metabo-
lized to prostaglandins (PGs), prostacyclin (PGI2), and
thromboxane A2 (TxA2). In contrast, AA is initially
converted to 5-hydroperoxyeicosatetraenoic acid (5-
HPETE) that is then transformed into leukotrienes
(LTs) via the 5-LOX pathway. The 8-LOX, 12-LOX,
Rofecoxib (1, see Fig. 1) belongs to a class of com-
pounds called coxibs that frequently possess two vicinal
diaryl moieties attached to a central heterocyclic ring. A
methanesulfonyl (MeSO2), or sulfonamide (SO2NH2),
substituent at the para-position of one of the phenyl
rings frequently confers selective COX-2 inhibitory
activity such that compounds of this type are useful
for the treatment of inflammatory diseases such as rheu-
matoid arthritis.5 Unlike traditional non-steroidal anti-
inflammatory drugs (NSAIDs) that inhibit both
Keywords: (E)-3-(4-Methanesulfonylphenyl)-2-(phenyl or biphe-
nyl)acrylic acids; Dual cyclooxygenase/lipoxygenase inhibitors; Anti-
inflammatory activity.
*
Corresponding author. Tel.: +1 780 492 5993; fax: +1 780 492
1217; e-mail: eknaus@pharmacy.ualberta.ca
0968-0896/$ - see front matter ꢀ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2006.08.008

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7717
urea moiety,9 or compounds that inhibit 5-LOX by a
non-specific redox mechanism10 such as quercetine (4).
Compounds possessing a 3,5-di-tert-butyl-4-hydroxy-
phenyl (DTBHP) moiety that can act as a redox inhibi-
tor, or antioxidant, to interfere with the redox cycle of
the 5-LOX isozyme have been investigated extensively
in the search for new dual COX/LOX inhibitors. In this
regard, S-2474 (5), a dual COX/5-LOX inhibitor in
which the DTBHP moiety is linked through a vinyl
bridge to a heterocyclic ring, was selected as an anti-ar-
thritic drug candidate that is now undergoing clinical
trials.11
MeO2S
N
CO2H
O
O
Cl
Licofelone (2)
Rofecoxib (1)
OH
OH
HO
N
NH2
HO
HO
O
O
Recently, we reported that the triaryl (Z)-ethene regioi-
somers (6a12a and 6b12b) having a COX-2 methanesulfo-
nyl (MeSO2) pharmacophore at the para-position of a
phenyl ring in conjunction with a R1 or R2-alkyl substi-
tuent of appropriate chain length exhibited selective
COX-2 inhibition. It was therefore of interest to design
a new class of acyclic analogs of rofecoxib (1) of general
structure 6 wherein R1 is a carboxyl group that could
potentially bind to Arg411 in the 5-LOX active site,8
and R2 is a hydrogen substituent, for evaluation as dual
inhibitors of COX-2 and 5-LOX. Accordingly, we now
describe the synthesis and biological evaluation of a
group of (E)-2-(phenyl or biphenyl)-3-(4-methanesulfo-
nylphenyl)acrylic acids (9a–h, 11a–d, and 12a–d).
S
OH
Zileuton (3)
O
Quercetine (4)
O
O
t-Bu
HO
MeO2S
S
N
R1
R2
t-Bu
S-2474 (5)
6a, R1 = n-alkyl, R2 = phenyl
6b, R1 = phenyl, R2 = n-alkyl
Figure 1. Some representative examples of cyclic (1) and acyclic (6a–b)
selective COX-2 inhibitors, a dual COX-2/5-LOX inhibitor (2), an iron
chelating 5-LOX inhibitor (3), and redox 5-LOX inhibitors (4 and 5).
2. Chemistry
COX-1 and COX-2, selective COX-2 inhibitors do not
induce adverse gastrointestinal irritation or hemorrhage.
However, an increased risk of myocardial infarction and
cardiovascular thrombotic events associated with the
use of some selective COX-2 inhibitors has been ob-
served. These adverse cardiovascular effects, which are
attributed to a decreased level of the vasodilatory
PGI2 and an increased level of the potent platelet aggre-
gator TxA2, were primarily responsible for the recent
witꢁhdrawal of rofecoxib (Vioxxꢁ) and valdecoxib (Bex-
tra ) from the market.6
The synthetic strategies used to prepare the target (E)-2-
aryl-3-(4-methanesulfonylphenyl)acrylic
illustrated in Schemes 1 and 2. The starting reagent,
acids
are
R1
CHO
R2
+
SO2Me
7
CO2H
8
Dual inhibitors of COX-2 and 5-LOX represent an
attractive safer alternative to selective COX-2 inhibitors:
in view of a potentially greater anti-inflammatory effica-
cy due to their ability to synergistically block both met-
abolic pathways of the AA cascade.1 In this regard,
licofelone (2), a dihydropyrrolizidine derivative, is a
dual COX-2/5-LOX inhibitor currently in clinical trials
for the treatment of osteoarthritis.7 Wouters and co-
workers8 recently proposed a model for binding of
non-redox inhibitors in the human 5-LOX active site
that consisted of four major anchoring points (two
hydrophobic groups, one hydrogen bond acceptor, and
an aromatic ring), and two secondary binding points
(an acidic moiety and an additional hydrogen bond
acceptor). The carboxyl group of licofelone would be
expected to undergo an electrostatic interaction with
Arg411 in this model for the active site of 5-LOX.8
Licofelone, being an active site direct 5-LOX inhibitor,
is more potent and selective than zileuton (3) which
inhibits 5-LOX by iron chelation involving its hydroxy-
(a)
R1
MeO2S
R2
CO2H
9a, R1 = R2 = H
9b, R1 = Br, R2 = H
9c, R1 = F, R2 = H
9d, R1 = OH, R2 = H
9e, R1 = OAc, R2 = H
9f, R1 = OMe, R2 = H
9g, R1 = NHAc, R2 = H (from 8 (R1 = NH2)
9h, R1 = H, R2 = Br
(b)
Scheme 1. Reagents and conditions: (a) Et3N, Ac2O, 90 ꢂC, 12 h; (b)
10% w/v aqueous NaOH, 25 ꢂC, 5 h.

7718
A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
R1
11a, R1 = OPr-i, R2 = H
11b, R1 = R2 = F
biphenyl-4-yl
biphenyl-3-yl
MeO2S
4
11c, R1 = SMe, R2 = H
(a)
R2
3
12a, R1 = OPr-i, R2 = H
12b, R1 = R2 = F
12c, R1 = SMe, R2 = H
MeO2S
4
Br
R2
CO2H
3
R1
+
B(OH)2
SO2Me
CO2H
MeO2S
4
10, R1 = H, F, OPr-i, SMe
11d, R1 = SO2Me, R2 = H
12d, R1 = SO2Me, R2 = H
9b (4-Br)
9h (3-Br)
biphenyl-4-yl
biphenyl-3-yl
R2 = H, F
(a), (b)
3
CO2H
Scheme 2. Reagents and conditions: (a) Pd(PPh3)4, Na2CO3, DME, reflux, 12 h; (b) Oxoneꢁ, MeOH, THF, 25 ꢂC, 15 h.
4-methanesulfonylbenzaldehyde (7), could be prepared
using either of two literature methods.13 Thus, protec-
tion of the carbonyl function present in 4-methylsufa-
nylbenzaldehyde as the dimethyl acetal, subsequent
oxidation of the methylsulfanyl to a methylsulfonyl sub-
stituent using meta-chloroperbenzoic acid (MCPBA),
and removal of the dimethyl acetal protecting group
yielded 4-methylsufonylbenzaldehyde (7) in 70% overall
yield. Alternatively, a nucleophilic aromatic substitution
reaction involving displacement of the fluoro substituent
in 4-fluorobenzaldehyde using sodium methane sulfinate
in freshly distilled DMSO gave 7 in 69% yield.
(or 3)-carboxymethylbenzenesulfonamides showed that
compounds having a 4-isopropoxyphenyl, 2,4-difluoro-
phenyl, or 4-methylsulfonylphenyl, substituent attached
to the benzenesulfonamide ring were the most potent
in vitro COX isozyme inhibitors and in vivo anti-inflam-
matory agents.
The Suzuki cross-coupling reaction between the aryl
bromide 9b or 9h, and either 4-isopropoxyphenylboron-
ic acid, 2,4-difluorophenylboronic acid or 4-(methyl-
thio)phenylboronic acid, in the presence of 2 M
aqueous sodium carbonate in ethylene glycol dimethyl
ether (DME) using tetrakis(triphenylphosphine)palladi-
um(0) as a catalyst afforded the respective target com-
pounds 11a–c, or 12a–c, in 21–67% yield. The
subsequent oxidation of the thiomethyl compounds
11c and 12c using Oxoneꢁ afforded the corresponding
methanesulfonyl compounds 11d and 12d in 38% and
64% yield, respectively.
The Perkin condensation14 of 4-methanesulfonylbenzal-
dehyde (7), and a substituted-phenylacetic acid (8),
afforded the respective (E)-3-(4-methanesulfonylphe-
nyl)-2-phenylacrylic acid (9a–c,e–h) in a moderate 9–
42% yield. The Perkin condensation of 7 with 4-amino-
phenylacetic acid (8, R1 = NH2, R2 = H), in which the
amino group is also acetylated, gave the N-acetylated
product 9g (R1 = NHCOMe, R2 = H). Alkaline hydro-
lysis of the acetoxy compound 9e (R1 = OAc, R2 = H),
obtained from the Perkin condensation of 7 with 4-acet-
oxyphenylacetic acid,15 yielded the phenolic compound
9d in 80% yield. The stereochemistry of the Perkin reac-
tion preferentially produces the a-phenylcinnamic acid
stereoisomer with cis-phenyl groups and an unhindered
carboxyl group. This stereochemical specificity is attrib-
uted to the fact that the initial condensation reaction is
not reversible, and that the reaction stereochemistry is
eliminatively controlled.14c
3. Results and discussion
In vitro structure–activity relationships acquired for this
group of (E)-2-(phenyl or biphenyl)-3-(4-methanesulfo-
nylphenyl)acrylic acids (9, 11, and 12) showed that they
exhibit a broad range (potent-to-inactive) of COX/LOX
inhibitory activities (COX-1 IC50 = 0.4 to >100 lM
range; COX-2 IC50 = 0.3 to >100 lM range; 5-LOX
IC50 = 0.11 to >10 lM range; 15-LOX IC50 = 0.31 to
>10 lM range; see data in Table 1). All of the com-
pounds 9 possessing a para-phenyl substituent (4-H, 4-
Br, 4-F, 4-OMe, and 4-NHAc), with the exception of
the inactive 4-OH and 4-OAc analogs, exhibited low-
to-moderate in vitro inhibition (IC50 = 0.88–31.6 lM
range) of the COX-1 isozyme. In the COX-2 isozyme
inhibition assay, all compounds (9a–g) in this group,
including the 4-OH and 4-OAc analogs, exhibited
weak-to-moderate activity (IC50 = 1.9–36.0 lM range).
In an earlier study,18 we reported that a hydroxy analog
of rofecoxib possessing a C-3 4-hydroxyphenyl substitu-
ent (see structure of rofecoxib in Fig. 1) was an inactive
The target (E)-3-(4-methanesulfonylphenyl)acrylic acids
11a–c and 12a–c, possessing a substituted-biphenyl ring
(R1 = H, F, i-OPr, SMe; R2 = H, F) attached to the
acrylic acid C-2 position, were prepared using a palladi-
um-catalyzed Suzuki cross-coupling reaction16 accord-
ing to the reaction sequence depicted in Scheme 2.
Compounds 11 and 12 having the following aryl substit-
uents
were
synthesized
(R1 = i-OPr,
R2 = H;
R1 = R2 = F; R1 = SO2Me, R2 = H) since biological
data from a previous study17 investigating N-acetyl-2-

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7719
Table 1. In vitro COX-1/COX-2 and 5-LOX/15-LOX enzyme inhibition assay data for (E)-2-(phenyl or biphenyl)-3-(4-methanesulfonylphe-
nyl)acrylic acids (9, 11, and 12)
MeO2S
4
R
3
H
CO2H
Selectivity index (SI)b
IC50 (lM)
a
a
c
3
Volume (A )
˚
Compound
R
IC50 (lM)
COX-1
COX-2
5-LOX
15-LOX
9a
9b
4-H
4-Br
1.5
3.0
3.6
0.50
0.24
—
>10
>10
>10
0.31
0.32
0.45
5.5
247.4
269.4
252.4
256.0
273.2
292.6
295.7
269.8
377.5
326.1
369.7
377.6
327.7
369.7
231.9
153.5
285.3
298.5
267.2
0.88
0.4
9c
9d
4-F
4-OH
36.0
5.3
1.3
0.56
>10
>10
0.11
>100
31.6
>100
3.2
>19
16.6
>34
1.3
9e
4-OMe
4-OAc
1.9
2.9
9f
9g
> 10
>10
>10
3.1
4-NHAc
3-Br
2.5
9h
11a
>100
>100
>100
>100
>100
>100
>100
0.31
0.32
0.32
0.32
>100
>100
2.1
>322
>312
>312
>312
—
>10
>10
4-(4-i-PrO–C6H4)–
4-(2,4-F2–C6H3)–
4-(4-MeO2S–C6H4)–
3-(4-i-PrO–C6H4)–
3-(2,4-F2–C6H3)–
3-(4-MeO2S–C6H4)–
11b
11d
3.1
0.49
>10
6.2
>10
>10
>10
>10
—
12a
12b
—
0.31
>10
3.2
12d
>47
Luteolin
Caffeic acid
NDGAd
Celecoxib
Rofecoxib
3.0
—
>10
—
3.5
33.1
>100
0.07
0.5
472
>200
—
—
—
a Values are means of two determinations acquired using an ovine COX-1/COX-2 and potato 5-LOX/soyabean 15-LOX, assay kits (Catalog Nos.
560101, 60401, and 760700, Cayman Chemicals Inc., Ann Arbor, MI, USA), and the deviation from the mean is <10% of the mean value.
b In vitro COX-2 selectivity index (COX-1 IC50/COX-2 IC50).
c The volume of the molecule after minimization using the PM3 force field was calculated using the Alchemy 2000 program.
d NDGA, nordihydroguaiaretic acid.
3
˚
inhibitor of either COX-1 or COX-2 (IC50 > 250 lM),
whereas the C-3 4-acetoxyphenyl analog of rofecoxib
was a potent COX-2 inhibitor (IC50 = 0.00126 lM)
having an extremely high COX-2 selectivity index
(SI > 79,365). In this regard, the ability of the 4-OH
(9d) compound to inhibit COX-2 distinguishes it from
the 4-hydroxy analog of rofecoxib.18 The point of
attachment of a bromo substituent was a determinant
of inhibitory activity since the 3-bromo isomer (9h)
was a more potent (IC50 = 0.31 lM) and selective
(SI > 322) COX-2 inhibitor, relative to the less potent
(IC50 = 3.6 lM) and selective (SI = 0.24) 4-bromo iso-
mer (9b).
and its associated secondary pocket (394 A ) is about
25% larger than that for the COX-1 binding site
3
(316 A ). A comparison of the molecular volumes
20
˚
(see data in Table 1) of compounds 9a–h possessing a
3
smaller substituted-phenyl moiety (247–273 A range)
˚
shows that COX-1 inhibitory activity is less than that
of compounds 11 and 12 having a larger substituted-bi-
3
phenyl moiety (326–377 A range) that are inactive
˚
COX-1 inhibitors. These data suggest that the latter
substituted-biphenyl compounds 11 and 12 are too large
to bind in the smaller COX-1 binding site. In this regard,
the biphenyl compounds 11a,b,d exhibited potent
(IC50 = 0.32 lM) and selective (SI > 312) COX-2 inhibi-
tory activities. The point of attachment of the two phen-
yl rings in the biphenyl compounds 11 and 12 was a
determinant of COX-2 inhibitory activity since the
biphenyl-4-yl isomers 11 were more potent than the cor-
responding biphenyl-3-yl regioisomers (12).
Although the binding sites of the COX-1 and COX-2
isozymes are highly similar such that they have virtually
identical tertiary and quaternary structures, there are
small structural differences between the two binding sites
that can be exploited in drug design. In this context, a
single amino acid residue lining the channel that differs
between COX-1 and COX-2 involves the presence of va-
line (Val523) in COX-2 versus isoleucine (Ile523) in
COX-1. Accordingly, the smaller valine side chain in
COX-2 induces a conformational change at Tyr355
thereby forming an additional hydrophobic secondary
internal pocket protruding off the primary binding site
in COX-2 that is absent in COX-1.19 Consequently,
the total volume of the COX-2 primary binding site
Structure–activity relationship 5-LOX/15-LOX inhibi-
tion studies suggest that the structural requirements
for 5-LOX inhibition are more stringent than for 15-
LOX inhibition. Wouters and co-workers8 recently pro-
posed a model that serves as a first step toward charac-
terization of human 5-LOX and its interaction with
ligands. This model is comprised of four major anchor-
ing points (two hydrophobic groups, one hydrogen
bond acceptor, and an aromatic ring), and two second-

7720
A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
ary binding points (an acidic moiety and an additional
hydrogen bond acceptor). Accordingly, it is plausible
that the 4-F (9c), 4-OH (9d) or 4-NHAc (9g) substituent
present in the 5-LOX inhibitory compounds investigated
may participate in a hydrogen-bonding interaction with
the 5-LOX binding site. Compounds 9c, 9d, and 9g were
more potent (5-LOX IC50 = 0.11–1.3 lM range) than
the reference drug caffeic acid (IC50 = 3.0 lM). A much
larger group of 4-substituted-phenyl compounds (9b, 4-
Br; 9c, 4-F; 9d, 4-OH; 9e, 4-OMe; IC50 = 0.31–5.5 lM
range), and substituted-biphenyl compounds (11a,b,
12a,b; IC50 = 0.31–6.2 lM range) showed moderate-to-
highly potent 15-LOX inhibitory activity relative to
the reference drugs luteolin (IC50 = 3.2 lM) and NDGA
(IC50 = 3.5 lM). Compounds 11b and 12b having a ter-
minal 2,4-difluorophenyl substituent exhibited optimal
15-LOX inhibition in the substituted-biphenyl group
of compounds 11 and 12.
O-atom forms a weak hydrogen bond with the NH of
˚
His90 (distance ꢀ 3.50 A). The 2,4-difluorophenyl moie-
ty that is cis to the C-3 p-MeSO2-phenyl group is orient-
ed in a hydrophobic pocket at the apex of the COX-2
binding site (Met522, Phe518, Trp387, Tyr385,
Leu384, and Leu352). The p-fluoro substituent is posi-
tioned within van der Waals contact range of the amino
˚
acid residues Met522 and Leu384 (distance < 5 A). The
distance between the centre of the C-1 4-substituted-
˚
phenyl ring and OH of Ser530 is about 5.04 A. The
COOH substituent attached to the central trans C@C
olefinic bond is oriented in an area close to the mouth
of the COX-2 binding site. It is interesting to note that
the C-1 COOH substituent undergoes both ion–ion
(electrostatic) and hydrogen-bonding interactions with
polar amino acid residues. The distance between the
NH2 of the charged Arg120 and the OH of the COOH
˚
substituent is about 3.13 A. In comparison, the distance
between the OH of Tyr355 and the OH of the COOH
˚
group is about 4.90 A. A hydrogen-bonding interaction
The most stable enzyme–ligand complex of the
potent and selective COX-2 inhibitor compound
11b {(E)-2-[4-(2,4-difluorophenyl)phenyl]-3-(4-metha-
nesulfonylphenyl)acrylic acid} docked in the COX-2 ac-
tive site (Fig. 2) shows that it binds in the primary
binding site such that the para-SO2Me COX-2 pharma-
cophore on the C-3 phenyl ring is oriented in the vicinity
of the secondary pocket present in COX-2 (Val523,
Phe518, Ile517, Ala516, Ser353, Leu352, and His90).
One of the O-atoms of the SO2Me moiety is involved
in a hydrogen-bonding interaction with the backbone
was also observed between the C@O of the COOH sub-
stituent and the OH of Ser121 that is closer to the mouth
˚
of the COX-2 binding site (distance ꢀ 3.19 A).
The binding interactions of the potent 5 and 15-LOX
inhibitor compound 11b {(E)-2-[4-(2,4-difluorophe-
nyl)phenyl]-3-(4-methanesulfonylphenyl)acrylic
acid}
within the 15-LOX binding site were investigated. The
most stable enzyme–ligand complex for 11b (Fig. 3)
shows that 11b is positioned in the 15-LOX binding site
such that the C-3 para-MeSO2-phenyl moiety is oriented
˚
NH of Ile517 (distance ꢀ 2.26 A), whereas the second
Figure 2. (E)-2-[4-(2,4-Difluorophenyl)phenyl]-3-(4-methanesulfonylphenyl)acrylic acid (11b) (ball and stick) docked in the active site of murine
COX-2. Hydrogen atoms of the amino acid residues have been removed to improve clarity.

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7721
Figure 3. (E)-2-[4-(2,4-Difluorophenyl)phenyl]-3-(4-methanesulfonylphenyl)acrylic acid (11b) (ball and stick) docked in the active site of soyabean
15-LOX. Hydrogen atoms of the amino acid residues have been removed to improve clarity.
toward the base of the binding site (Ile593, Met419,
Ile418, and Phe415). The p-SO2Me COX-2 pharmaco-
phore is located within van der Waals contact range of
the amino acid residues Ile593, Met419, and Ile418 (dis-
and His361. The O-atom of the p-HO-phenyl group
undergoes a hydrogen bond interaction with the NH
˚
of His361 (distance ꢀ 2.0 A). The C-1 COOH substitu-
ent is surrounded by Gln548 and Gly598. The distance
between the OH (of COOH) and the NH2 of Gln548
˚
tance < 5 A). The 2,4-difluorophenyl group is oriented
toward a hydrophobic region comprised of the amino
acid residues Leu597, Trp595, Ile414, and Leu408 closer
˚
is about 4.59 A. The C@O of the COOH substituent
forms a hydrogen bond with the backbone NH of
˚
to the base of the 15-LOX binding site (distance < 5 A).
˚
Gly598 (distance ꢀ 2.73 A). There is a large spatial sep-
It is interesting to note that the C-1 COOH group is ori-
ented toward the catalytic site (His545, His366, and
His361) where it undergoes an ion–ion (electrostatic)
interaction. The distance between the NH of His361
aration between the COOH substituent and the charged
Arg403 that is located at the mouth of the 15-LOX bind-
˚
ing site (distance > 13 A).
˚
and the OH of the COOH substituent is about 4.53 A.
The (E)-3-(4-methanesulfonylphenyl)acrylic acids pos-
sessing C-2 4-hydroxyphenyl (9d), 4-acetylaminophenyl
(9g), and 4-(2,4-difluorophenyl)phenyl] (11b) aryl moie-
ties, based on in vitro COX and LOX isozyme inhibition
data, were selected for further in vivo pharmacological
evaluation to determine their anti-inflammatory (AI)
and analgesic activities (see data in Table 2). In a carra-
geenan-induced rat paw edema assay model, the relative
potency order was NHAc (9g, ED50 = 109.5 mg/
kg) ꢀ 2,4-F2–C6H3– (11b, ED50 = 112.4 mg/kg) > OH
(9d, ED50 = 363.4 mg/kg) relative to the 5-LOX inhibi-
tor caffeic acid (8.2% inhibition for a 30 mg/kg dose),
the 15-LOX inhibitor nordihydroguaiaretic acid
(NDGA, ED50 = 205 mg/kg), the non-selective COX-1/
COX-2 inhibitor aspirin (ED50 = 129 mg/kg), and selec-
tive COX-2 inhibitor celecoxib (ED50 = 10.8 mg/kg) ref-
erence drugs. One plausible explanation for the lower
potency of the OH compound 9d, relative to the NHAc
(9g) and 2,4-F2–C6H3– (11b) compounds, may be due to
In comparison, the distance between the NH of
His361 and the C@O of the COOH substituent is about
4.06 A. There is a relative large spatial separation be-
tween the COOH substituent and the charged Arg403
that is located at the mouth of the 15-LOX binding site
˚
(distance > 10 A). This latter observation indicates that
˚
interaction of the C-1 CO2H with Arg403 is not a
requirement for 15-LOX inhibitory activity.
A similar molecular modeling study was performed
where compound 9d [(E)-2-(4-hydroxyphenyl)-3-(4-
methanesulfonylphenyl)acrylic acid] was docked in the
15-LOX binding site (Fig. 4). This study showed that
the C-3 para-MeSO2-phenyl moiety is oriented toward
the catalytic site near His545, Ile544, His366, and
His361. The C-1 p-hydroxyphenyl group that is cis to
the C-3 para-MeSO2-phenyl moiety is oriented in a re-
gion comprised of Leu597, Gln548, Leu408, Glu357,

7722
A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
Figure 4. (E)-2-(4-Hydroxyphenyl)-3-(4-methanesulfonylphenyl)acrylic acid (9d) (ball and stick) docked in the active site of soyabean 15-LOX.
Hydrogen atoms of the amino acid residues have been removed to improve clarity.
Table 2. In vivo anti-inflammatory and analgesic activities for (E)-2-(4-hydroxyphenyl)-3-(4-methanesulfonylphenyl)acrylic acid (9d), (E)-2-(4-
acetylaminophenyl)-3-(4-methanesulfonylphenyl)acrylic acid (9g), and (E)-2-[4-(2,4-difluorophenyl)phenyl]-3-(4-methanesulfonylphenyl)acrylic
acid (11b)
MeO2S
R
H
CO2H
Compound
R
AI activitya
Analgesic activityb
ED50 (mg/kg)
% Inhibition (30 min)
% Inhibition (60 min)
9d
9g
–OH
–NHAc
(2,4-F2-C6H3)–
363.4
109.5
112.4
8.2 2.5c
205.0
129.0
10.8
54.1 5.8
72.0 3.3
73.3 3.1
47.2 10.6d
45.8 9.2d
56.5 9.8
31.7 9.6
45.8 5.8
68.0 3.2
63.3 7.7
58.3 12.8d
62.5 4.8d
54.3 13.7
62.0 7.3
11b
Caffeic acid
NDGA
Aspirin
Celecoxib
—
—
—
—
a Inhibitory activity in a carrageenan-induced rat paw edema assay. The results are expressed as means SEM (n = 4) at 3 h following a 30 mg/kg
oral dose of the test compound or as the ED50 value when it was determined.
b Inhibitory activity in the rat 4% NaCl-induced abdominal constriction assay. The results are expressed as means SEM (n = 4–5) following a
50 mg/kg oral dose of the test compound.
c Percent (%) inhibition of inflammation for a 30 mg/kg oral dose.
d Percent (%) reduction in abdominal constrictions for a 30 mg/kg oral dose.
the greater ability of 9d to form inactive O-glucuronide
and/or O-sulfate conjugates. In vitro COX isozyme inhi-
bition studies (Table 1) showed that 9d is a moderately
selective COX-2 inhibitor (SI > 19), 9g is a non-selective
COX-2 inhibitor (SI = 1.3), and 11b is a highly selective
COX-2 inhibitor (SI > 312). Compounds 9g and 11b are

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7723
equipotent anti-inflammatory agents even though there
5.1. General procedure for the synthesis of (E)-acrylic
acids (9a–c and 9e–h)
is a large difference in their COX-2 potency. According-
ly, further studies are required to develop a data bank to
determine the most ideal COX-2/COX-1 and 5-LOX/15-
LOX values for anti-inflammatory efficacy.
A solution of 4-methanesulfonylbenzaldehyde (7, 1.38 g,
7.5 mmol), the appropriate phenylacetic acid (8,
7.5 mmol), and triethylamine (1.02 mL, 7.3 mmol) in
acetic anhydride (6.95 mL) was stirred at 90 ꢂC for
16 h. After cooling to 25 ꢂC, diethyl ether (30 mL) and
water (20 mL) were added, and the organic phase was
extracted with 10% w/v aqueous NaOH (3· 30 mL).
The combined aqueous layers were acidified to pH 2
using concentrated HCl, the precipitate was filtered
off, the precipitate was dissolved in EtOAc, and the
EtOAc solution was dried (Na2SO4). Removal of the
solvent under vacuum afforded a residue which was
purified by silica gel column chromatography using
EtOAc–petroleum ether (7:3, v/v) as eluant. Physical,
spectral, and microanalytical data for 9a–c and 9e–h
are listed below.
In a rat 4% NaCl-induced abdominal constriction (anal-
gesic) assay, a 50 mg oral dose of the (E)-olefins 9d, 9g,
and 11b exhibited good analgesic activities (45–73%
range) comparable to the reference drugs caffeic acid,
NDGA, aspirin, and celecoxib at 30 and 60 min post-
drug administration (see data in Table 2).
4. Conclusions
A new class of (E)-2-(aryl)-3-(4-methanesulfonylphe-
nyl)acrylic acids were designed that possess para-meth-
anesulfonylphenyl (COX-2), and substituted-phenyl or
-biphenyl (5-LOX), pharmacophores for evaluation as
dual acting COX/LOX inhibitors. The structure–activ-
ity data acquired indicate that two compounds
(9d and 11b) exhibit an interesting combination of
COX-2/5-LOX/15-LOX inhibitory activities. (E)-2-(4-
Hydroxyphenyl)-3-(4-methanesulfonylphenyl)acrylic
acid (9d) is a weak, but moderately selective (SI > 19),
COX-2 inhibitor that is simultaneously a potent bal-
anced inhibitor of both 5-LOX (IC50 = 0.56 lM)
and 15-LOX (IC50 = 0.45 lM). In comparison,
(E)-2-[4-(2,4-difluorophenyl)phenyl]-3-(4-methanesulfo-
5.2. (E)-3-(4-Methanesulfonylphenyl)-2-phenylacrylic
acid (9a)
Yield, 42%; white powder; mp 176–178 ꢂC; IR (film):
3463–2530 (COOH), 1686 (C@O), 1304 (SO2), 1219,
1
1149 cmÀ1; H NMR (CDCl3) d 3.02 (s, 3H, CH3SO2),
7.19–7.26 (m, 4H, 4-methanesulfonylphenyl H-2, H-6,
phenyl H-3, H-5), 7.36–7.43 (m, 3H, phenyl H-2, H-6,
H-4), 7.75 (d, J = 8.2 Hz, 2H, 4-methanesulfonylphenyl
H-3, H-5), 7.96 (s, 1H, H-3). Anal. Calcd for
C16H14O4S: C, 63.56; H, 4.67. Found: C, 63.76; H, 4.93.
nylphenyl)acrylic acid (11b) is
a
potent (IC50
= 0.32 lM) and selective (SI > 312) COX-2 inhibitor
that is also an effective inhibitor of 5-LOX
(IC50 = 3.1 lM) and 15-LOX (IC50 = 0.49 lM). The
modeling studies show that substituent steric bulk (vol-
ume), regiochemistry, and electronic parameters modu-
late COX-2 and 15-LOX ligand–enzyme binding
interactions which can facilitate the interpretation of
in vitro enzyme inhibition structure–activity data.
5.3. (E)-2-(4-Bromophenyl)-3-(4-methanesulfonylphe-
nyl)acrylic acid (9b)
Yield, 9%; white powder; mp 250–252 ꢂC; IR (film) 3430–
2712 (COOH), 1688 (C@O), 1307 (SO2), 1223,
1150 cmÀ1; 1H NMR (DMSO-d6) d 3.14 (s, 3H, CH3SO2),
7.11 (d, J = 8.2 Hz, 2H, 4-bromophenyl H-3, H-5), 7.29
(d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-2, H-6),
7.55 (d, J = 8.2 Hz, 2H, 4-bromophenyl H-2, H-6), 7.73
(d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-3, H-5),
7.82 (s, 1H, H-3). Anal. Calcd for C16H13BrO4S: C,
50.41; H, 3.44. Found: C, 50.29; H, 3.49.
5. Experimental
Melting points were determined using a Thomas-Hoo-
ver capillary apparatus and are uncorrected. Infrared
(IR) spectra were recorded as films on NaCl plates using
5.4. (E)-2-(4-Fluorophenyl)-3-(4-methanesulfonylphe-
nyl)acrylic acid (9c)
1
a Nicolet 550 Series II Magna FT-IR spectrometer. H
NMR spectra were measured on a Bruker AM-300 spec-
trometer in CDCl3 or CDCl3 + DMSO-d6 as solvent
with TMS as the internal standard, where J (coupling
constant) values are estimated in Hertz. Spin multiplets
are given as s (singlet), d (doublet), t (triplet), q (quar-
tet), m (multiplet), and br (broad). Microanalyses were
performed for C and H (Microanalytical Service Labo-
ratory, Department of Chemistry, University of Alber-
ta), and were within 0.4% of theoretical values. Silica
gel column chromatography was performed using
Merck silica gel 60 ASTM (70–230 mesh). Luteolin, caf-
feic acid, and nordihydroguaiaretic acid (NDGA) were
purchased from Cayman Chemicals (Ann Arbor, MI).
All other reagents, purchased from the Aldrich Chemi-
cal Company (Milwaukee, WI), were used without fur-
ther purification.
Yield, 11%; white crystals; mp 243–245 ꢂC; IR (film)
3473–2713 (COOH), 1685 (C@O), 1307 (SO2), 1222,
1151 cmÀ1
;
1H NMR (DMSO-d6) d 3.17 (s, 3H,
CH3SO2), 7.16–7.22 (m, J = 7.3 Hz, 4H, 4-fluorophenyl
hydrogens), 7.29 (d, J = 8.2 Hz, 2H, 4-methanesulfonyl-
phenyl H-2, H-6), 7.75 (d, J = 8.2 Hz, 2H, 4-metha-
nesulfonylphenyl H-3, H-5), 7.83 (s, 1H, H-3). Anal.
Calcd for C16H13FO4S: C, 59.99; H, 4.09. Found: C,
59.73; H, 4.13.
5.5. (E)-2-(4-Acetoxyphenyl)-3-(4-methanesulfonylphe-
nyl)acrylic acid (9e)
Yield, 32% (from 4-acetoxyphenylacetic acid); bright
white crystals; mp 242–243 ꢂC; IR (film): 3513–2487

7724
A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
(COOH), 1764 (C@O of OAc), 1686 (C@O), 1298 (SO2),
1219, 1149 cmÀ1 1H NMR (CDCl3) d 2.23 (s, 3H,
acetate (3· 20 mL), the combined organic layers were
washed with brine, and the EtOAc solution was dried
(MgSO4). Removal of the organic solvent under vacuum
furnished a residue which was purified by silica gel col-
umn chromatography using EtOAc–petroleum ether
(8:2, v/v) as eluant to yield 9d (80%) as a pale yellow
powder; mp 219–221 ꢂC; IR (film) 3488–2844 (COOH),
;
COCH3), 2.94 (s, 3H, CH3SO2), 7.02 (d, J = 8.5 Hz,
2H, 4-acetoxyphenyl H-3, H-5), 7.14 (d, J = 8.5 Hz,
2H, 4-acetoxyphenyl H-2, H-6), 7.15 (d, J = 8.5 Hz,
2H, 4-methanesulfonylphenyl H-2, H-6), 7.64 (d,
J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-3, H-5),
7.78 (s, 1H, H-3). Anal. Calcd for C18H16O6S: C,
59.99; H, 4.47. Found: C, 59.68; H, 4.39.
1
1685 (C@O), 1297 (SO2), 1217, 1146 cmÀ1; H NMR
(DMSO-d6)
d 3.18 (s, 3H, CH3SO2), 6.75 (d,
J = 8.5 Hz, 2H, 4-hydroxyphenyl H-3, H-5), 6.96 (d,
J = 8.5 Hz, 2H, 4-hydroxyphenyl H-2, H-6), 7.32 (d,
J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-2, H-6),
7.72 (s, 1H, H-3), 7.75 (d, J = 8.5 Hz, 2H, 4-metha-
nesulfonylphenyl H-3, H-5), 9.59 (br s, 1H, OH), 12.82
(br s, 1H, CO2H). Anal. Calcd for C16H14O5S: C,
60.37; H, 4.43. Found: C, 59.97; H, 4.57.
5.6. (E)-3-(4-Methanesulfonylphenyl)-2-(4-methoxyphe-
nyl)acrylic acid (9f)
Yield, 41%; yellow powder; mp 210–211 ꢂC; IR (film):
2610–3482 (COOH), 1684 (C@O), 1293 (SO2), 1219,
1
1149 cmÀ1; H NMR (CDCl3) d 3.03 (s, 3H, CH3SO2),
3.85 (s, 3H, OCH3), 6.92 (d, J = 8.5 Hz, 2H, 4-methoxy-
phenyl H-3, H-5), 7.14 (d, J = 8.5 Hz, 2H, 4-methoxy-
phenyl H-2, H-6), 7.28 (d, J = 8.5 Hz, 2H, 4-
methanesulfonylphenyl H-2, H-6), 7.76 (d, J = 8.5 Hz,
2H, 4-methanesulfonylphenyl H-3, H-5), 7.91 (s, 1H,
H-3). Anal. Calcd for C17H16O5S: C, 61.43; H, 4.85.
Found: C, 61.17; H, 4.93.
5.10. General procedure for the synthesis of (E)-acrylic
acids (11a–c and 12a–c)
An aqueous Na2CO3 solution (5.8 mL of 2 M),
and tetrakis(triphenylphosphine)palladium (67 mg,
0.058 mmol) were added to a solution of either (E)-2-
(4-bromophenyl)-3-(4-methanesulfonylphenyl)acrylic
acid (9b), or (E)-2-(3-bromophenyl)-3-(4-methanesulfo-
nylphenyl)acrylic acid (9h, 0.74 g, 1.94 mmol), and a
substituted-phenylboronic acid (10, 2.91 mmol), in
DME (20 mL). The reaction was allowed to proceed at
reflux for 16 h, the reaction mixture was cooled to
25 ꢂC, and the solvent was removed in vaccuo. Ethyl
acetate (30 mL) and water (10 mL) were added, and
the mixture was acidified to pH 3 using an aqueous solu-
tion of HCl (10% w/v) prior to extraction with ethyl ace-
tate (2· 20 mL). The organic layers were combined,
washed with brine, and the organic fraction was dried
(Na2SO4). Removal of the solvent under vacuum gave
a residue which was purified by silica gel column chro-
matography using chloroform–methanol (9.5:0.5, v/v)
as eluant. Physical, spectral, and microanalytical data
for 11–c and 12a–c are listed below.
5.7. (E)-2-(4-Acetylaminophenyl)-3-(4-methanesulfonyl-
phenyl)acrylic acid (9g)
Yield, 32% (from 4-aminophenylacetic acid); pale yellow
powder; mp 275–277 ꢂC; IR (film): 1733 (C@O), 1683
(C@O), 1218 cmÀ1 1H NMR (DMSO-d6) d 2.06 (s,
;
3H, COCH3), 3.18 (s, 3H, CH3SO2), 7.09 (d,
J = 8.5 Hz, 2H, 4-acetylaminophenyl H-2, H-6), 7.32
(d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-2, H-
6), 7.58 (d, J = 8.5 Hz, 2H, 4-acetylaminophenyl H-3,
H-5), 7.75 (d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl
H-3, H-5), 7.78 (s, 1H, H-3), 10.03 (br s, 1H, NH),
12.93 (br s, 1H, CO2H). Anal. Calcd for C18H17NO5S:
C, 60.15; H, 4.77. Found: C, 59.93; H, 4.80.
5.8. (E)-2-(3-Bromophenyl)-3-(4-methanesulfonylphe-
nyl)acrylic acid (9h)
5.11. (E)-2-[4-(Isopropoxyphenyl)phenyl]-3-(4-metha-
nesulfonylphenyl)acrylic acid (11a)
Yield, 18%; white crystals; mp 200–201 ꢂC; IR (film)
3460–2698 (COOH), 1679 (C@O), 1306 (SO2), 1228,
1146 cmÀ1
;
1H NMR (DMSO-d6) d 3.19 (s, 3H,
Yield, 28%; pale yellow cotton form; mp 228–230 ꢂC; IR
(film) 3453–2728 (COOH), 1683 (C@O), 1306 (SO2),
CH3SO2), 7.17 (d, J = 7.6 Hz, 1H, bromophenyl H-4),
7.30–7.37 (m, 3H, 4-methanesulfonylphenyl H-2, H-6,
bromophenyl H-5), 7.44 (t, J = 1.3 Hz, 1H, bromophe-
nyl H-2), 7.58 (dd, J = 8.2, 1.3 Hz, 1H, bromophenyl
H-6), 7.78 (d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl
H-3, H-5), 7.87 (s, 1H, H-3), 13.09 (br s, 1H, CO2H).
Anal. Calcd for C16H13BrO4S: C, 50.41; H, 3.44. Found:
C, 50.31; H, 3.53.
1244, 1150 cmÀ1 1H NMR (DMSO-d6) d 1.29 (d,
;
J = 6.1 Hz, 6H, CH(CH3)2), 3.18 (s, 3H, CH3SO2),
4.67 (septet, J = 6.1 Hz, 1H, CH(CH3)2), 7.00 (d,
J = 8.8 Hz, 2H, 4-isopropoxyphenyl H-3, H-5), 7.23 (d,
J = 8.2 Hz, 2H, 1,4-disubstituted-phenyl H-2, H-6),
7.36 (d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-2,
H-6), 7.62–7.66 (m, 4H, 4-isopropoxyphenyl H-2, H-6,
1,4-disubstituted-phenyl H-3, H-5), 7.75 (d, J = 8.5 Hz,
2H, 4-methanesulfonylphenyl H-3, H-5), 7.88 (s, 1H,
H-3). Anal. Calcd for C25H24O5S: C, 68.79; H, 5.54.
Found: C, 68.55; H, 5.45.
5.9. Synthesis of (E)-2-(4-hydroxyphenyl)-3-(4-metha-
nesulfonylphenyl)acrylic acid (9d)
A solution of 10% w/v aqueous NaOH (25 mmol, 1.0 g)
was added to a solution of (E)-2-(4-acetoxyphenyl)-3-(4-
5.12. (E)-2-[4-(2,4-Difluorophenyl)phenyl]-3-(4-metha-
nesulfonylphenyl)acrylic acid (11b)
methanesulfonylphenyl)acrylic
acid
(9e,
1.80 g,
5.0 mmol) in methanol (20 mL). The reaction mixture
was stirred at 25 ꢂC for 5 h and then concentrated under
vaccuo. The residue obtained was extracted with ethyl
Yield, 60%; white powder; mp 226–227 ꢂC; IR (film)
3347–2773 (COOH), 1682 (C@O), 1304 (SO2), 1221,

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7725
1
1149 cmÀ1; H NMR (CDCl3) d 2.99 (s, 3H, CH3SO2),
6.90–7.00 (m, 2H, 2,4-difluorophenyl H-3, H-5), 7.21
(d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl H-2, H-
6), 7.22 (d, J = 8.2 Hz, 2H, 1,4-disubstituted-phenyl H-
2, H-6), 7.40–7.49 (m, 1H, 2,4-difluorophenyl H-6),
7.44 (d, J = 8.2 Hz, 2H, 1,4-disubstituted-phenyl H-3,
H-5), 7.66 (d, J = 8.5 Hz, 2H, 4-methanesulfonylphenyl
H-3, H-5), 7.80 (s, 1H, H-3). Anal. Calcd for
C22H16F2O4S: C, 63.76; H, 3.89. Found: C, 63.61; H,
3.93.
5.16. (E)-3-(4-Methanesulfonylphenyl)-2-[3-(4-meth-
ylsulfanylphenyl)phenyl]acrylic acid (12c)
Yield, 67%; beige powder; mp 183–185 ꢂC; IR (film)
3438–2708 (COOH), 1683 (C@O), 1303 (SO2), 1218,
1148 cmÀ1
SCH3), 3.17 (s, 3H, CH3SO2), 7.15 (d, J = 7.6 Hz, 1H,
;
1H NMR (DMSO-d6) d 2.49 (s, 3H,
1,3-disubstituted-phenyl H-4), 7.31 (d, J = 8.2 Hz, 2H,
(d,
4-methanesulfonylphenyl
H-2,
H-6),
7.36
J = 8.5 Hz, 2H, 4-methylsulfanylphenyl H-3, H-5), 7.45
(s, 1H, 1,3-disubstituted-phenyl H-2), 7.46 (t,
J = 7.6 Hz, 1H, 1,3-disubstituted-phenyl H-5), 7.53 (d,
J = 8.5 Hz, 2H, 4-methylsulfanylphenyl H-2, H-6), 7.66
(d, J = 7.6 Hz, 1H, 1,3-disubstituted-phenyl H-6), 7.75
(d, J = 8.2 Hz, 2H, 4-methanesulfonylphenyl H-3, H-
5), 7.88 (s, 1H, H-3), 13.03 (br s, 1H, CO2H). Anal.
Calcd for C23H20O4S2: C, 65.07; H, 4.75. Found: C,
64.79; H, 4.73.
5.13. (E)-3-(4-Methanesulfonylphenyl)-2-[4-(methylsulfa-
nylphenyl)phenyl]acrylic acid (11c)
Yield, 44%; yellow powder; mp 244–245 ꢂC; IR (film)
3388–2667 (COOH), 1685 (C@O), 1306 (SO2), 1221,
1153 cmÀ1
;
1H NMR (DMSO-d6) d 2.52 (s, 3H,
SCH3), 3.18 (s, 3H, CH3SO2), 7.26 (d, J = 8.2 Hz, 2H,
4-methylsulfanylphenyl H-3, H-5), 7.36 (d, J = 8.5 Hz,
2H, 4-methanesulfonylphenyl H-2, H-6), 7.37 (d,
J = 8.2 Hz, 2H, 4-methylsulfanylphenyl H-2, H-6), 7.68
and 7.70 (two d, J = 8.2 Hz, 2H each, 1,4-disubstitut-
ed-phenyl H-2, H-6 and H-3, H-5), 7.76 (d, J = 8.5 Hz,
2H, 4-methanesulfonylphenyl H-3, H-5), 7.85 (s, 1H,
H-3), 13.01 (br s, 1H, CO2H). Anal. Calcd for
C23H20O4S2: C, 65.07; H, 4.75. Found: C, 64.78; H,
4.82.
5.17. General procedure for the synthesis of (E)-acrylic
acids (11d and 12d)
A solution of Oxoneꢁ (potassium peroxymonosulfate)
(1.45 g, 2.36 mmol) in water (8 mL) was added dropwise
at 0 ꢂC to a solution of 11c or 12c (0.50 g, 1.18 mmol) in
THF–MeOH (1:1, v/v, 4 mL). The reaction was allowed
to proceed for 15 h at 25 ꢂC with stirring, and then the
solvent was removed in vacuo. Water (20 mL) was added
to the residue and this mixture was extracted with EtOAc
(3· 30 mL), the combined organic layers were washed
with water and then dried (Na2SO4). Removal of the sol-
vent in vacuo afforded a solid residue which was recrys-
tallized from 95% EtOH. The physical, spectral and
microanalytical data for 11d and 12d are listed below.
5.14. (E)-2-[3-(4-Isopropoxyphenyl)phenyl]-3-(4-metha-
nesulfonylphenyl)acrylic acid (12a)
Yield, 50%; white crystals; mp 177–179 ꢂC; IR (film)
3503–2703 (COOH), 1686 (C@O), 1306 (SO2), 1247,
1151 cmÀ1
;
1H NMR (DMSO-d6)
d
1.27 (d,
J = 5.8 Hz, 6H, CH(CH3)2), 3.17 (s, 3H, CH3SO2),
4.64 (septet, J = 5.8 Hz, 1H, CH(CH3)2), 6.96 (d,
J = 8.8 Hz, 2H, 4-isopropoxyphenyl H-3, H-5), 7.10 (d,
J = 8.2 Hz, 1H, 1,3-disubstituted-phenyl H-4), 7.36 (d,
J = 8.2 Hz, 2H, 4-methanesulfonylphenyl H-2, H-6),
7.40–7.46 (m, 2H, 1,3-disubstituted-phenyl H-2, H-5),
7.48 (d, J = 8.5 Hz, 2H, 4-isopropoxyphenyl H-2, H-6),
7.62 (d, J = 8.2 Hz, 1H, 1,3-disubstituted-phenyl H-6),
7.75 (d, J = 8.2 Hz, 2H, 4-methanesulfonylphenyl H-3,
H-5), 7.87 (s, 1H, H-3) 13.00 (br s, 1H, CO2H). Anal.
Calcd for C25H24O5S: C, 68.79; H, 5.54. Found: C,
68.78; H, 5.43.
5.18. (E)-2-[4-(Methanesulfonylphenyl)phenyl]-3-(4-
methanesulfonylphenyl)acrylic acid (11d)
Yield, 38%; white solid; mp 255–256 ꢂC; IR (film) 3453–
2688 (COOH), 1683 (C@O), 1304 (SO2), 1219,
1153 cmÀ1
;
1H NMR (DMSO-d6) d 3.18 (s, 3H,
CH3SO2), 3.27 (s, 3H, biphenyl CH3SO2), 7.34 and
7.36 (two d, J = 8.2 Hz, 2H each, 4-methanesulfonylphe-
nyl H-2, H-6), 7.76 and 7.80 (two d, J = 8.2 Hz, 2H
each, 1,4-disubstituted-phenyl H-2, H-6 and H-3, H-5),
7.88 (s, 1H, H-3), 8.00–8.04 (m, 4H total, 4-metha-
nesulfonylphenyl H-3, H-5), 13.05 (br s, 1H, CO2H).
Anal. Calcd for C23H20O6S2: C, 60.51; H, 4.42. Found:
C, 60.37; H, 4.45.
5.15. (E)-2-[3-(2,4-Difluorophenyl)phenyl]-3-(4-metha-
nesulfonylphenyl)acrylic acid (12b)
Yield, 21%; white solid; mp 214–216 ꢂC; IR (film)
3438–2733 (COOH), 1684 (C@O), 1307 (SO2), 1222,
5.19. (E)-2-[3-(4-Methanesulfonylphenyl)phenyl]-3-(4-
methanesulfonylphenyl)acrylic acid (12d)
1150 cmÀ1
;
1H NMR (DMSO-d6) d 3.18 (s, 3H,
CH3SO2), 7.13–7.24 (m, 2H, 2,4-difluorophenyl H-3,
H-5), 7.30–7.38 (m, 2H, 1,3-disubstituted-phenyl H-4,
H-5), 7.35 (d, J = 8.2 Hz, 2H, 4-methanesulfonylphe-
nyl H-2, H-6), 7.43–7.50 (m, 2H, 1,3-disubstituted-
phenyl H-6, 2,4-difluorophenyl H-6), 7.52 (s, 1H,
1,3-disubstituted-phenyl H-2), 7.76 (d, J = 8.2 Hz,
2H, 4-methanesulfonylphenyl H-3, H-5), 7.88 (s, 1H,
H-3), 13.05 (br s, 1H, CO2H). Anal. Calcd for
C22H16F2O4S: C, 63.76; H, 3.89. Found: C, 63.53;
H, 3.97.
Yield, 64%; white cotton form; mp 204–205 ꢂC; IR (film)
3433–2683 (COOH), 1683 (C@O), 1304 (SO2), 1219,
1149 cmÀ1
;
1H NMR (DMSO-d6) d 3.17 (s, 3H,
CH3SO2), 3.24 (s, 3H, biphenyl CH3SO2), 7.25 (d,
J = 7.6 Hz, 1H, 1,3-disubstituted-phenyl H-4), 7.36 (d,
J = 8.5 Hz, 4-methanesulfonylphenyl H-2, H-6), 7.53
(t, J = 7.8 Hz, 1H, 1,3-disubstituted-phenyl H-5), 7.58
(s, 1H, 1,3-disubstituted-phenyl H-2), 7.75 (d,
J = 8.2 Hz, 2H, biphenyl 4-methanesulfonylphenyl H-
2, H-6), 7.77 (d, J = 7.6 Hz, 1H, 1,3-disubstituted-phen-

7726
A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
yl H-6), 7.85 (s, 1H, H-3), 7.89 (d, J = 8.5 Hz, 2H, 4-
methanesulfonylphenyl H-3, H-5), 7.98 (d, J = 8.5 Hz,
2H, biphenyl 4-methanesulfonylphenyl H-3, H-5),
13.06 (br s, 1H, CO2H). Anal. Calcd for C23H20O6S2:
C, 60.51; H, 4.42. Found: C, 60.59; H, 4.69.
instructions. The Cayman Chemical lipoxygenase inhib-
itor screening assay detects and measures the hydroper-
oxides produced in the lipoxygenation reaction using a
purified lipoxygenase. Stock solutions of test com-
pounds, prepared immediately before use, were dis-
solved in a minimum volume of DMSO and were
diluted using the supplied buffer solution (0.1 M Tris–
HCl, pH 7.4). To a 90 ll solution of 5- or 15-LOX en-
zyme in 0.1 M Tris–HCl, pH 7.4 buffer, 10 ll of various
concentrations of test drug solutions (0.001, 0.01, 0.1, 1,
and 10 lM in a final volume of 210 ll) was added and
the lipoxygenase reaction was initiated by the addition
of 10 ll (100 lM) of linoleic acid (LA). After maintain-
ing the 96-well plate on a shaker for 5 min, 100 ll of
chromogen was added and the plate was retained on a
shaker for 5 min. The lipoxygenase activity was deter-
mined after measuring absorbance at a wavelength of
490 nm. Percent inhibition was calculated by the com-
parison of compound-treated to various control incuba-
tions. The concentration of the test compound causing
50% inhibition (IC50, lM) was calculated from the con-
6. Molecular modeling (docking) studies
Docking experiments were performed using Insight II
software Version 2000.1 (Accelrys Inc.) running on a Sil-
icon Graphics Octane 2 R14000A workstation. The
coordinates for the X-ray crystal structure of the enzyme
COX-2 and 15-LOX were obtained from the RCSB Pro-
tein Data Bank and hydrogens were added. The ligand
molecules were constructed using the Builder module
and energy-minimized for 1000 iterations reaching a
˚
convergence of 0.01 kcal/mol A. The docking experi-
ment on COX-2 was carried out by superimposing the
energy-minimized ligand on SC-558 in the PDB file
1cx2 after which SC-558 was deleted. The coordinates
for 15-LOX were obtained from PDB file1lox and the
energy-minimized ligand was superimposed on the
inhibitor RS75091 after which RS75091 was deleted.
In all these experiments the resulting ligand–enzyme
complex was subjected to docking using the Affinity
command in the Docking module of Insight II after
defining subsets of the enzyme such that residues within
centration–inhibition
response
curve
(duplicate
determinations).
9. Anti-inflammatory assay
Anti-inflammatory activity was performed using a meth-
od described by Winter et al.21
˚
10 A of the ligand were allowed to relax, while the
remainder of the enzyme residues were fixed. The consis-
tent valence force field (CVFF) was employed for all
docking purposes. The ligand–enzyme assembly was
10. Analgesic assay
then subjected to
a
molecular dynamics (MD)
simulation using the Discover module Version 2.98 at
a constant temperature of 300 K with a 100-step equili-
bration for over 1000 iterations and a time step of 1 fs
using a distance-dependent dielectric constant 4r. The
optimal binding orientation of the ligand–enzyme
assembly obtained after docking was further minimized
for 1000 iterations using the conjugate gradient method
until a convergence of 0.001 kcal/mol A was reached
after which Eintermolecular (kcal/mol) of the ligand–en-
zyme assembly was evaluated.
Analgesic activity was determined using a 4% sodium
chloride-induced writhing (abdominal constriction)
assay previously reported.22
Acknowledgments
˚
We are grateful to (i) the Canadian Institutes of Health
Research (CIHR) (MOP-14712) for financial support of
this research, (ii) Rx& D-HRF/CIHR for a postdoctoral
fellowship (to Q.H.C.), and to the Alberta Heritage
Foundation for Medical Research (AHFMR) for a
postdoctoral fellowship award (to Q.H.C.).
7. In vitro cyclooxygenase (COX) inhibition assays
The ability of the test compounds listed in Table 1 to
inhibit ovine COX-1 and COX-2 (IC50 value, lM) was
determined using an enzyme immunoassay (EIA) kit
(Catalog No. 560101, Cayman Chemical, Ann Arbor,
MI, USA) according to our previously reported
method.12a
References and notes
1. (a) Fiorucci, S.; Meli, R.; Bucci, M.; Cirino, G. Biochem.
Pharmacol. 2001, 62, 1433; (b) Charlier, C.; Michaux, C.
Eur. J. Med. Chem. 2003, 38, 645.
2. (a) Samuelsson, B. Science 1983, 220, 568; (b) Weissmann,
G. J. Lipid Mediators 1993, 6, 275; (c) Jampilek, J.;
Dolezal, M.; Opletalova, V.; Hartl, J. Curr. Med. Chem.
2006, 13, 117.
8. In vitro lipoxygenase (LOX) inhibition assays
3. (a) Ding, X.-Z.; Hennig, R.; Adrian, T. E. Mol. Cancer
2003, 2, 10; (b) Pommery, N.; Taverne, T.; Telliez, A.;
Goossens, L.; Charlier, C.; Pommery, J.; Goossens, J.-F.;
The ability of the test compounds to inhibit potato 5-
LOX (Catalog No. 60401, Cayman Chemical, Ann Ar-
bor, MI, USA) and soybean 15-LOX (Catalog No.
760700, Cayman Chemical, Ann Arbor, MI, USA)
(IC50 values, lM) was determined using an enzyme
immunoassay (EIA) kit according to the manufacturer’s
´
Houssin, R.; Durant, F.; Henichart, J.-P. J. Med. Chem.
2004, 47, 6195.
4. (a) Mehrabian, M.; Allayee, H. Curr. Opin. Lipidol. 2003,
14, 447; (b) Vila, L. Med. Res. Rev. 2004, 24, 399; (c)

A. Moreau et al. / Bioorg. Med. Chem. 14 (2006) 7716–7727
7727
Zhao, L.; Funk, C. D. Trends Cardiovasc. Med. 2004, 14,
191; (d) Dwyer, J. H.; Allayee, H.; Dwyer, K. M.; Fan, J.;
Wu, H.; Mar, R.; Lusis, A. J.; Mehrabian, M. N. Engl. J.
Med. 2004, 350, 29.
M.; Kawai, S.; Matsumoto, S. J. Med. Chem. 2000, 43,
2040; (b) Yagami, T.; Ueda, K.; Asakura, K.; Sakaeda, T.;
Kuroda, T.; Hata, S.; Kambayashi, Y.; Fujimoto, M. Br.
J. Pharmacol. 2001, 134, 673.
5. (a) Talley, J. J.; Bertenshaw, S. R.; Brown, D. L.; Carter,
J. S.; Graneto, M. J.; Koboldt, C. M.; Masferrer, J. L.;
Norman, B. H.; Rogier, D. J., Jr.; Zweifel, B. S.; Seibert,
K. Med. Res. Rev. 1999, 19, 199; (b) Dannhardt, G.;
Laufer, S. Curr. Med. Chem. 2000, 7, 1101.
12. (a) Uddin, M. J.; Rao, P. N. P.; McDonald, R.; Knaus,
E. E. J. Med. Chem. 2004, 47, 6108; (b) Uddin, M. J.;
Rao, P. N. P.; Knaus, E. E. Bioorg. Med. Chem. 2004,
12, 5929.
13. (a) Creary, X.; Mehrsheikh-Mohammadi, M. E. J. Org.
Chem. 1986, 51, 1110; (b) Ulman, A.; Urankar, E. J. Org.
Chem. 1989, 54, 4691.
14. (a) Nodiff, E. A.; Tanabe, K.; Seyfried, C.; Matsuura, S.;
Kondo, Y.; Chen, E. H.; Tyagi, M. P. J. Med. Chem. 1971,
14, 921; (b) Jonnalagadda, S. S.; Haar, E. T.; Hamel, E.;
Lin, C. M.; Magarian, R. A.; Day, B. W. Bioorg. Med.
Chem. 1997, 5, 715; (c) Zimmerman, H. E.; Ahramjian, L.
J. Am. Chem. Soc. 1959, 81, 2086.
15. Tran-Huu-Dau, M.-E.; Wartchow, R.; Winterfeldt, E.;
Wong, Y.-S. Chem. Eur. J. 2001, 7, 2349.
16. (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457; (b)
Stanforth, S. P. Tetrahedron 1998, 54, 263.
17. Chen, Q.-H.; Rao, P. N. P.; Knaus, E. E. Bioorg. Med.
Chem. 2005, 13, 4694.
18. Rahim, M. A.; Rao, P. N. P.; Knaus, E. E. Bioorg. Med.
Chem. Lett. 2002, 12, 2753.
6. (a) Vioxxꢁ (Rofecoxib) sales suspended by Merck Sharp &
Dohme-Chibret on September 30, 2004; (b) Bextraꢁ
(Valdecoxib) sales suspended by Pfizer on April 12,
´
2005; (c) Dogne, J.-M.; Supuran, C. T.; Pratico, D. J.
Med. Chem. 2005, 48, 2251.
7. Ding, C.; Cicuttini, F. IDrugs: Invest. Drugs J. 2003, 6,
802.
´
8. Charlier, C.; Henichart, J.-P.; Durant, F.; Wouters, J.
J. Med. Chem. 2006, 49, 186.
9. (a) Carter, G. W.; Young, P. R.; Albert, D. H.; Bouska, J.;
Dyer, R.; Bell, R. L.; Summers, J. B.; Brooks, D. W. J.
Pharmacol. Exp. Ther. 1991, 256, 929; (b) Wenzel, S. E.;
Kamada, A. K. Ann. Pharmacother. 1996, 30, 858; (c)
Muri, E. M. F.; Nieto, M. J.; Sindelar, R. D.; Williamson,
J. S. Curr. Med. Chem. 2002, 9, 1631.
10. (a) Fitzpatrick, L. R.; Bostwick, J. S.; Renzetti, M.;
Pendleton, R. G.; Decktor, D. L. Agents Actions 1990, 30,
393; (b) Schewe, T.; Sadik, C.; Klotz, L.-O.; Yoshimoto,
T.; Kuhn, H.; Sies, H. Biol. Chem. 2001, 382, 1687; (c) Chi,
Y. S.; Jong, H. G.; Son, K. H.; Chang, H. W.; Kang, S. S.;
Kim, H. P. Biochem. Pharmacol. 2001, 62, 1185; (d)
Whitman, S.; Gezginci, M.; Timmermann, B. N.; Holman,
T. R. J. Med. Chem. 2002, 45, 2659.
19. Kurumbail, R. G.; Stevens, A. M.; Gierse, J. K.;
McDonald, J. J.; Stegeman, R. A.; Pak, J. Y.; Gildehaus,
D.; Miyashiro, J. M.; Penning, T. D.; Seibert, K.; Isakson,
P. C.; Stallings, W. C. Nature 1996, 384, 644.
20. Luong, C.; Miller, A.; Barnett, J.; Chow, J.; Ramesha, C.;
Browner, M. F. Nat. Struct. Biol. 1996, 3, 927.
21. Winter, C. A.; Risley, E. A.; Nuss, G. W. Proc. Soc. Exp.
Biol. Med. 1962, 111, 544.
11. (a) Inagaki, M.; Tsuri, T.; Jyoyama, H.; Ono, T.; Yamada,
K.; Kobayashi, M.; Hori, Y.; Arimura, A.; Yasui, K.;
Ohno, K.; Kakudo, S.; Koizumi, K.; Suzuki, R.; Kato,
22. Fukawa, K.; Kawano, O.; Hibi, M.; Misaka, N.; Ohba, S.;
Hatanaka, Y. J. Pharmacol. Methods 1980, 4, 251.