Synthesis of new 1-(2-, 3-, or 4-methanesulfonylphenyl)-2-[5-(N- hydroxypyridin-2(1H)-one)]acetylene regioisomers: A search for novel cyclooxygenase and lipoxygenase inhibitors

Article abstract of DOI:10.1002/jhet.23

A group of acetylene regioisomers were designed such that a cyclooxygenase-2 (COX-2) SO₂Me pharmacophore was located at the ortho-, meta-, or para-position of the acetylene C-1 phenyl ring, and an iron-chelating 5-lipoxygenase (5-LOX) N-hydroxy

Full text of DOI:10.1002/jhet.23

58
Synthesis of New 1-(2-, 3-, Or 4-Methanesulfonylphenyl)-2-[5-
(N-hydroxypyridin-2(1H)-one)]acetylene Regioisomers: A Search
for Novel Cyclooxygenase and Lipoxygenase Inhibitors
Vol 46
Morshed A. Chowdhury,a Hua Chen,b Khaled R. A. Abdellatif,a Ying Dong,a
Kenneth C. Petruk,b and Edward E. Knausa*
aFaculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alta,
Canada T6G 2N8
bFaculty of Medicine and Dentistry, University of Alberta, Edmonton, Alta, Canada T6G 2R7
*E-mail: eknaus@pharmacy.ualberta.ca
Received June 4, 2008
DOI 10.1002/jhet.23
Published online 11 February 2009 in Wiley InterScience (www.interscience.wiley.com).
A group of acetylene regioisomers were designed such that a cyclooxygenase-2 (COX-2) SO2Me
pharmacophore was located at the ortho-, meta-, or para-position of the acetylene C-1 phenyl ring, and
an iron-chelating 5-lipoxygenase (5-LOX) N-hydroxypyridin-2(1H)-one moiety was attached via its C-5
position to the C-2 position on an acetylene template (scaffold). These target linear acetylene regioisom-
ers were synthesized via a palladium-catalyzed Sonogashira cross-coupling reaction. Structure-activity
data acquired using in vitro cell-based inhibition assays indicated that this novel class of 1-(2-, 3-, or
4-methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-one)]acetylene regioisomers did not inhibit the
COX-2 or (5-LOX) enzymes, and that they are devoid of in vivo anti-inflammatory activities.
J. Heterocyclic Chem., 46, 58 (2009).
INTRODUCTION
3-, or 4-methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-
2(1H)-one)]acetylene regioisomers (8a–c), to determine
their potential utility as inhibitors of the COX-2 and 5-
LOX enzymes.
Dual inhibitors of cyclooxygenase-2 (COX-2) and 5-
lipoxygenase (5-LOX) represent an attractive safer alter-
native to selective COX-2 inhibitors. This view is based
on
a potentially greater anti-inflammatory efficacy
because of their ability to synergistically block both
metabolic pathways of the arachidonic acid (AA) cas-
cade [1]. A group of 1-(2-, 3-, and 4-methanesulfonyl-
phenyl)-2-(2-, 3-, and 4-pyridyl)acetylene regioisomers,
which are effective COX-1/COX-2 inhibitors that ex-
hibit in vivo anti-inflammatory activities, were recently
reported [2]. The most successful effort to develop 5-
LOX inhibitors has been in the area of hydroxamic acids
and related N-hydroxyureas that likely chelate iron pres-
ent in the 5-LOX enzyme [3]. The recently described 1-
(methanesulfonlylphenyl)-2-(pyridyl)acetylene regioisom-
ers possess a suitable scaffold (template) to design novel
acyclic dual inhibitors of the COX and LOX enzymes
[2]. It was anticipated that replacement of the pyridyl
ring in these parent acetylenes by a N-hydroxypyridin-
2(1H)one moiety, which has the potential to chelate iron,
may provide a hitherto unknown class of dual COX/5-
LOX inhibitory anti-inflammatory agents. Accordingly,
we now describe the synthesis of a novel group of 1-(2-,
RESULTS AND DISCUSSION
1-(Methylthiophenyl)-2-(2-methoxypyrid-5-yl)acetyl-
enes (6a–c) were prepared in 28–72% yield using two
consecutive palladium-catalyzed Sonogashira cross-cou-
pling reactions [2,4–7]. The subsequent transformation
of 6a–c to the target 1-(2-, 3-, or 4-methanesulfonyl-
phenyl)-2-[5-(N-hydroxypyridin-2(1H)-one)]acetylene
regioisomers (8a–c) was carried out using the synthetic
methodologies shown in Scheme 1. A modified proce-
dure [8] was used to synthesize 5-ethynyl-2-methoxy-
pyridine (4). Thus, Sonogashira coupling of 5-bromo-2-
methoxypyridine (1) with 2-methylbut-3-yn-2-ol (2) in
the presence of Et3N, cuprous iodide (CuI), and
dichloro-bis(triphenylphosphine)palladium(0)
([PdCl2
(PPh3)2]) catalyst afforded 4-(2-methoxypyridin-5-yl)-2-
methyl-but-3-yn-2-ol (3) in 75% yield. Subsequent re-
moval of the isopropanol moiety using sodium hydride
furnished 5-ethynyl-2-methoxypyridine (4) in 82% yield.
C
V
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Synthesis of New 1-(2-, 3- or 4-Methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-one)]
acetylene Regioisomers: A Search for Novel Cyclooxygenase and Lipoxygenase Inhibitors
59
Scheme 1. Reagents and conditions: (a) Et3N, Pd(PPh3)2Cl2, CuI, 70–
75ꢁC, 3 h; (b) benzene, NaH, 105–110ꢁC, 1 h; (c) Et3N, Pd(PPh3)2Cl2,
CuI, 90ꢁC, 5 h; (d) m-chloroperoxybenzoic acid, CH2Cl2, 25ꢁC, over-
night; (e) (i) acetyl chloride, reflux, 1 h; (ii) MeOH, 25ꢁC, overnight.
to serve as effective iron chelators to exhibit 5-LOX in-
hibitory activity. However, these cyclic N-hydroxypyri-
din-2(1H)-ones, unlike acyclic hydroxamic acids which
undergo facile biotransformation to the carboxylic acids,
are expected to be metabolically stable with improved
oral efficacy.
In vitro cell-based inhibition assays were carried out
to determine the biological effect of compounds 8a–c on
eicosanoid synthesis/release by measuring the amounts
of cysteinyl leukotrienes (collectively referred to as a
group of 5-LOX derived metabolites LTC4, LTD4, and
LTE4) and prostaglandin E2 (PGE2) secreted into the
culture medium of human brain cancer cells. The assay
to determine the ability of 8a–c to inhibit in vitro cell-
based 5-LOX activity showed that all three regioisomers
failed to inhibit the 5-LOX enzyme (IC50 > 50 lM)
relative to the reference drug nordihydroguaiaretic acid
(NDGA, IC50 ¼ 35 lM). Compounds 8a–c were simi-
larly inactive (IC50 > 100 lM) inhibitors of the COX-2
isozyme relative to the reference drug celecoxib (IC50
2.5 lM) in a cell-based assay.
¼
The anti-inflammatory activities exhibited by the
regioisomers 8a–c were determined using a carrageenan-
induced rat foot paw edema model at a 50 mg/kg oral
dose. In this assay, compounds 8a–c were all inactive
anti-inflammatory (AI) agents compared with the refer-
ence drug celecoxib (79.9 ꢀ 1.9% inhibition at 50 mg/
kg po; ID50 ¼ 10.8 mg/kg po).
A second Sonogashira cross-coupling reaction of 4 with
the halothioanisole (5a–c) regioisomers was carried out
under an argon atmosphere in Et3N using [PdCl2
(PPh3)2]/CuI as catalyst to furnish the respective 1-
(methylthiophenyl)-2-(2-methoxypyrid-5-yl)acetylenes
6a–c in 28–72% yield. Oxidation of 6a–c with meta-
chloroperbenzoic acid in dichloromethane [9] afforded
The biological data acquired in this study indicate
that the 1-(methanesulfonylphenyl)-2-[5-(N-hydroxypyri-
din-2(1H)-one)]acetylene structure is not a suitable tem-
plate for the design of anti-inflammatory agents that act
by inhibition of the 5-LOX and/or COX-2 enzymes.
the
1-(methanesulfonylphenyl)-2-(1-oxido-2-methoxy-
pyrid-5-yl)acetylenes (7a–c) in 44–51% yield. Finally,
reaction of the N-oxides 7a–c with acetyl chloride at
reflux, and then methanolysis in place of hydrolysis [9]
furnished the target N-hydroxypyridin-2(1H)-ones (8a–c)
in 69–91% yield.
EXPERIMENTAL
Melting points were determined on a Thomas-Hoover capil-
lary apparatus and are uncorrected. Unless otherwise noted,
infrared (IR) spectra were recorded as films on NaCl plates
using a Nicolet 550 Series II Magna FTIR spectrometer. 1H
NMR spectra were measured on a Bruker AM-300 spectrome-
ter in CDCl3 or CDCl3 þ DMSO-d6 with TMS as the internal
standard. Microanalyses were performed for C, H, N (Micro-
Analytical Service Laboratory, Department of Chemistry, Uni-
versity of Alberta) and were within ꢀ0.4% of theoretical val-
ues. Silica gel column chromatography was performed using
Merck silica gel 60 ASTM (70-230 mesh). 2-Iodothioanisole
(5a) [12] and 3-iodothioanisole (5b) [13] were synthesized in
91% and 76% yields, respectively, starting from 2-(methyl-
thio)aniline and 3-(methylthio)aniline using the procedure of
Ullmann [14]. All other reagents, purchased from the Aldrich
Chemical Company (Milwaukee, WI), were used without fur-
ther purification.
Replacement of the carboxyl (CO2H) in traditional
arylacetic acid nonsteroidal anti-inflammatory drugs
(NSAIDs) by a hydroxamic acid (CONHOH) moiety
provided potent orally active 5-LOX inhibitory agents
[10]. NSAIDs having a CONHOH or CON(Me)OH
(pKa 9–11 range) in place of the CO2H in traditional
NSAIDs (pKa generally in the 4–5 range) are much less
acidic, which decreases ulcerogenicity [11].
The rational for the design of the acyclic acetylenes
8a-c was based on the expectations that (i) the phenyl
ring bearing the SO2Me pharmacophore will confer
COX-2 inhibitory activity, and (ii) the N-hydroxypyri-
din-2(1H)one moiety will confer 5-LOX inhibitory ac-
tivity. The CONOH part of the N-hydroxypyrid-2(1H)-
one ring present in 8a–c can be viewed as a cyclic
hydroxamic acid mimetic. These N-hydroxypyridin-
2(1H)-ones, like acyclic hydroxamic acids, are expected
4-(2-Methoxypyridin-5-yl)-2-methylbut-3-yn-2-ol (3). PdCl2
(PPh3)2 (63 mg, 0.09 mmoles) and CuI (19 mg, 0.10 mmoles)
were added to a stirred solution of 5-bromo-2-methoxypyridine
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

60
M. A. Chowdhury, H. Chen, K. R. A. Abdellatif, Y. Dong, K. C. Petruk, and E. E. Knaus
Vol 46
(1) (2.75 mL, 21.39 mmoles) and 2-methylbut-3-yn-2-ol (2)
(2.20 mL, 22.61 mmoles) in Et3N (40 mL) under an argon
atmosphere at 25ꢁC, and the reaction was allowed to proceed
at 70–75ꢁC for 3 h. The reaction mixture was allowed to cool
to 25ꢁC, filtered, and excess Et3N was removed from the fil-
trate in vacuo. The dark brown residue obtained was purified
by silica gel column chromatography using hexane-EtOAc
(3:1, v/v) as eluent to afford 3 in 75% yield; yellowish oil; IR
SMe), 4.00 (s, 3H, OMe), 6.77 (d, J ¼ 8.5 Hz, 1H, pyridyl H-
3), 7.21 (d, J ¼ 8.5 Hz, 2H, phenyl H-3, H-5), 7.43 (d, J ¼
8.5 Hz, 2H, phenyl H-2, H-6), 7.72 (dd, J ¼ 8.5, 2.1 Hz, 1H,
pyridyl H-4), 8.36 (d, J ¼ 2.1 Hz, 1H, pyridyl H-6).
General procedure for the synthesis of 1-(methane-
sulfonylphenyl)-2-(1-oxido-2-methoxypyrid-5-yl)acetylenes
(7a-c). m-Chloroperoxybenzoic acid (77% max.) (12 mmoles)
was added to a stirred solution of a 1-(methylthiophenyl)-2-(2-
methoxypyrid-5-yl)acetylene (6a, 6b, or 6c, 2 mmoles) in dry
CH2Cl2 (25 mL), and the reaction was allowed to proceed
with stirring at 25ꢁC overnight. The solvent CH2Cl2 was
removed in vacuo to give a crude product, which was purified
by silica gel column chromatography using methanol-EtOAc
(2:3, v/v) as eluent to afford the respective product 7a–c.
Some physical and spectroscopic data for 7a–c are listed
below.
(film): 3368 (OH), 2235 (CBC) cmꢂ1 1H NMR (CDCl3) d
;
1.62 (s, 6H, CMe2), 2.44 (br s, 1H, OH), 3.94 (s, 3H, OMe),
6.69 (d, J ¼ 8.5 Hz, 1H, pyridyl H-3), 7.59 (dd, J ¼ 8.5, 2.1
Hz, 1H, pyridyl H-4), 8.27 (d, J ¼ 2.1 Hz, 1H, pyridyl H-6).
5-Ethynyl-2-methoxypyridine (4). Sodium hydride (26 mg,
1.08 mmoles) was added to a solution of 4-(2-methoxypyridin-
5-yl)-2-methylbut-3-yn-2-ol (3) (1.52 g, 7.96 mmoles) in ben-
zene (7 mL), and the reaction mixture was heated at 105–
110ꢁC for 1 h. Removal of the solvent in vacuo gave a dark
brown oil, which was purified by silica gel column chromatog-
raphy using hexane-EtOAc (3:1, v/v) as eluent to afford 4 in
1-(2-Methanesulfonylphenyl)-2-(1-oxido-2-methoxypyrid-5-
yl)acetylene (7a). Yield, 48%; pale yellow solid; mp 140–
142ꢁC; IR (film): 2220 (CBC), 1669, 1602, 1521 (Ar), 1313,
1145 (SO2) cmꢂ1 1H NMR (CDCl3) d 3.25 (s, 3H, SO2Me),
;
1
82% yield; brown oil; IR (film): 2230 (CBC) cmꢂ1; H NMR
4.16 (s, 3H, OMe), 6.98 (d, J ¼ 8.5 Hz, 1H, pyridyl H-3),
7.52–7.70 (m, 3H, pyridyl H-4, phenyl H-4, H-5), 7.74 (dd, J
¼ 7.6, 1.5 Hz, 1H, phenyl H-6), 8.15 (dd, J ¼ 7.6, 1.5 Hz,
1H, phenyl H-3), 8.54 (d, J ¼ 1.8 Hz, 1H, pyridyl H-6).
1-(3-Methanesulfonylphenyl)-2-(1-oxido-2-methoxypyrid-5-
yl)acetylene (7b). Yield, 51%; pale yellow solid; mp 172–
174ꢁC; IR (film): 2227 (CBC), 1609, 1528 (Ar), 1307, 1145
(CDCl3) d 3.12 (s, 1H, CBCH), 3.96 (s, 3H, OMe), 6.72 (d, J
¼ 8.5 Hz, 1H, pyridyl H-3), 7.66 (dd, J ¼ 8.5, 2.1 Hz, 1H,
pyridyl H-4), 8.27 (d, J ¼ 2.1 Hz, 1H, pyridyl H-6).
General procedure for the synthesis of 1-(methylthio-
phenyl)-2-(2-methoxypyrid-5-yl)acetylenes (6a–c). CuI (46
mg, 0.24 mmoles) was added with stirring to a solution
containing PdCl2(PPh3)2 (85 mg, 0.12 mmoles), 5-ethynyl-2-
methoxypyridine (4) (6 mmoles), and a halothioanisole 5a, 5b,
or 5c (4 mmoles), in Et3N (10 mL) under an argon atmos-
phere. The reaction mixture was heated at 90ꢁC for 5 h, cooled
to 25ꢁC, and filtered to remove the inorganic salts. The solvent
from the filtrate was removed in vacuo, and the residue
obtained was purified by silica gel column chromatography
using hexane-EtOAc (10:1, v/v) as eluent to furnish the respec-
tive product 6a–c. Some physical and spectroscopic data for
6a–c are listed below.
(SO2) cmꢂ1 1H NMR (CDCl3) d 3.09 (s, 3H, SO2Me), 4.14
;
(s, 3H, OMe), 6.93 (d, J ¼ 8.5 Hz, 1H, pyridyl H-3), 7.47 (dd,
J ¼ 8.5, 1.8 Hz, 1H, pyridyl H-4), 7.61 (dd, J ¼ 7.6, 7.6 Hz,
1H, phenyl H-5), 7.77 (ddd, J ¼ 7.6, 1.5, 1.2 Hz, 1H, phenyl
H-6), 7.95 (ddd, J ¼ 7.6, 1.5, 1.2 Hz, 1H, phenyl H-4), 8.10
(dd, J ¼ 1.5, 1.2 Hz, 1H, phenyl H-2), 8.45 (d, J ¼ 1.8 Hz,
1H, pyridyl H-6).
1-(4-Methanesulfonylphenyl)-2-(1-oxido-2-methoxypyrid-5-
yl)acetylene (7c). Yield, 44%; white solid; mp 175–177ꢁC; IR
(film): 2227 (CBC), 1602, 1522 (Ar), 1300, 1146 (SO2) cmꢂ1
;
1-(2-Methylthiophenyl)-2-(2-methoxypyrid-5-yl)acetylene
(6a). The product was obtained as a pale yellow oil using the
Sonogashira coupling reaction of 4 with 2-iodothioanisole (5a)
in 72% yield; IR (film): 2213 (CBC), 1615, 1580, 1488 (Ar)
1H NMR (CDCl3) d 3.08 (s, 3H, SO2Me), 4.14 (s, 3H, OMe),
6.93 (d, J ¼ 8.9 Hz, 1H, pyridyl H-3), 7.48 (d, J ¼ 8.9, 1.8
Hz, 1H, pyridyl H-4), 7.71 (d, J ¼ 8.5 Hz, 2H phenyl H-2, H-
6), 7.95 (d, J ¼ 8.5 Hz, 2H, phenyl H-3, H-5), 8.46 (d, J ¼
1.8 Hz, 1H, pyridyl H-6).
cmꢂ1 1H NMR (CDCl3) d 2.52 (s, 3H, SMe), 4.00 (s, 3H,
;
OMe), 6.77 (d, J ¼ 8.5 Hz, 1H, pyridyl H-3), 7.12 (ddd, J ¼
7.6, 7.6, 1.2 Hz, 1H, phenyl H-5), 7.19 (dd, J ¼ 7.6, 1.2 Hz,
1H, phenyl H-3), 7.31 (ddd, J ¼ 7.6, 7.6, 1.2 Hz, 1H, phenyl
H-4), 7.48 (d, J ¼ 7.6, 1.2 Hz, 1H, phenyl H-6), 7.77 (dd, J ¼
8.5, 2.1 Hz, 1H, pyridyl H-4), 8.41 (d, J ¼ 2.1 Hz, 1H, pyridyl
H-6).
General procedure for the synthesis of 1-(methanesulfonyl-
phenyl)-2-[5-(N-hydroxypyridin-2(1H)-one)]acetylenes (8a-c).
Acetyl chloride (6 mL) was added to a 1-(methanesulfonyl-
phenyl)-2-(1-oxido-2-methoxypyrid-5-yl)acetylene (7a, 7b or
7c, 2 mmoles) and the reaction was allowed to proceed at
reflux for 1 hour. The reaction mixture was cooled to 25ꢁC,
and excess acetyl chloride was removed in vacuo. The residue
was dissolved in methanol prior to stirring at 25ꢁC overnight.
Methanol was removed in vacuo to give a solid product which
was then mixed with Et2O (10 mL) to form a slurry. Finally
the product was filtered out and dried under vacuum to give
the respective product (8a-c). The spectral and microanalytical
data for compounds 8a-c are listed below.
1-(3-Methylthiophenyl)-2-(2-methoxypyrid-5-yl)acetylene
(6b). The product was obtained as a pale yellow oil using the
Sonogashira coupling reaction of 4 with 3-iodothioanisole (5b)
in 44% yield; IR (film): 2229 (CBC), 1588, 1560, 1495 (Ar)
cmꢂ1 1H NMR (CDCl3) d 2.51 (s, 3H, SMe), 3.99 (s, 3H,
;
OMe), 6.77 (d, J ¼ 8.9 Hz, 1H, pyridyl H-3), 7.20–7.31 (m,
3H, phenyl H-4, H-5, H-6), 7.39 (s, 1H, phenyl H-2), 7.72 (dd,
J ¼ 8.9, 2.1 Hz, 1H, pyridyl H-4), 8.36 (d, J ¼ 2.1 Hz, 1H,
pyridyl H-6).
1-(2-Methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-
one)]acetylene (8a). Yield, 71%; brown solid; mp 198–200ꢁC;
1-(4-Methylthiophenyl)-2-(2-methoxypyrid-5-yl)acetylene
(6c). The product was obtained as a pale yellow solid using
the Sonogashira coupling reaction of 4 with 4-bromothioani-
sole (5c) in 28% yield; mp 85–87ꢁC; IR (film): 2230 (CBC),
IR (film): 2210 (CBC), 1650 (CO), 1300, 1140 (SO2) cmꢂ1
;
1H NMR (CDCl3 þ DMSO-d6) d 3.18 (s, 3H, SO2Me), 6.54
(d, J ¼ 9.2 Hz, 1H, pyridone H-3), 7.39 (dd, J ¼ 9.2, 1.2 Hz,
1H, pyridone H-4), 7.46 (dd, J ¼ 7.6, 7.6 Hz, 1H, phenyl H-
1
1602, 1560, 1495 (Ar) cmꢂ1; H NMR (CDCl3) d 2.51 (s, 3H,
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Synthesis of New 1-(2-, 3- or 4-Methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-one)]
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61
5), 7.55 (dd, J ¼ 7.6, 7.6 Hz, 1H, phenyl H-4), 7.60 (d, J ¼
7.6 Hz, 1H, phenyl H-6), 7.93 (d, J ¼ 1.2 Hz, 1H, pyridone
H-6), 7.99 (d, J ¼ 7.6 Hz, 1H, phenyl H-3). Anal. Calcd for
C14H11NO4Sꢃ1/2H2O: C, 56.32; H, 4.02; N, 4.69. Found: C,
56.30; H, 4.10; N, 4.83.
tions of eicosanoids were determined using prostaglandin E2
(catalog number 514010) and cysteinyl leukotriene (catalog
number 520501) enzyme immunoassay kits (Cayman Chemi-
cal, Ann Arbor, MI) according to a previously reported method
[16].
1-(3-Methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-
one)]acetylene (8b). Yield, 69%; brown solid; mp 205–207ꢁC;
In vivo anti-inflammatory assay. The test compounds 8a–c
and the reference drug celecoxib were evaluated using the in
vivo carrageenan-induced foot paw edema model reported pre-
viously [17].
IR (KBr): 2210 (CBC), 1650 (CO), 1300, 1145 (SO2) cmꢂ1
;
1H NMR (CDCl3 þ DMSO-d6) d 3.01 (s, 3H, SO2Me), 6.54
(d, J ¼ 9.4 Hz, 1H, pyridone H-3), 7.35 (dd, J ¼ 9.4, 2.4 Hz,
1H, pyridone H-4), 7.50 (dd, J ¼ 7.6, 7.6 Hz, 1H, phenyl H-
5), 7.65 (ddd, J ¼ 7.6, 2.7, 1.5 Hz, 1H, phenyl H-6), 7.80
(ddd, J ¼ 7.6, 2.7, 1.5 Hz, 1H, phenyl H-4), 7.89 (d, J ¼ 2.4
Hz, 1H, pyridone H-6), 7.93 (dd, J ¼ 1.5, 1.5 Hz, 1H, phenyl
H-2). Anal. Calcd for C14H11NO4Sꢃ1/2H2O: C, 56.32; H, 4.02;
N, 4.69. Found: C, 56.71; H, 3.80; N, 4.83.
Acknowledgment. The authors are grateful to the Canadian
Institutes of Health Research (CIHR) for financial support
(MOP-14712) of this research.
REFERENCES AND NOTES
1-(4-Methanesulfonylphenyl)-2-[5-(N-hydroxypyridin-2(1H)-
one)]acetylene (8c). Yield, 91%; pale yellow solid; mp 234–
236ꢁC; IR (film): 2211 (CBC), 1651 (CO), 1300, 1144 (SO2)
[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.
1
cmꢂ1; H NMR (CDCl3) d 3.20 (s, 3H, SO2Me), 6.55 (d, J ¼
[2] Chowdhury, M. A.; Dong, Y.; Chen, Q.-H.; Abdellatif, K.
R. A.; Knaus, E. E. Bioorg Med Chem 2008, 16, 1948.
[3] Muri, E. M. F.; Nieto, M. J.; Sindelar, R. D.; Williamson,
J. S. Curr Med Chem 2002, 9, 1631.
9.5 Hz, 1H, pyridone H-3), 7.50 (dd, J ¼ 9.5, 2.4 Hz, 1H, pyr-
idone H-4), 7.70 (d, J ¼ 8.5 Hz, 2H phenyl H-2, H-6), 7.93
(d, J ¼ 8.5 Hz, 2H, phenyl H-3, H-5), 8.33 (d, J ¼ 2.4 Hz,
1H, pyridone H-6), 12.1 (br s, 1H, N-OH). Anal. Calcd for
C14H11NO4S: C, 58.12; H, 3.83; N, 4.84. Found: C, 57.80; H,
3.87; N, 4.95.
[4] Chen, Q.-H.; Rao, P. N. P.; Knaus, E. E. Bioorg Med Chem
2005, 13, 6425.
[5] Anana, R.; Rao, P. N. P.; Chen, Q.-H.; Knaus, E. E. Biorg
Med Chem 2006, 14, 5259.
In vitro cell-based enzyme immunoassays for determina-
tion of prostaglandin E2 (COX-2) and cysteinyl leuko-
trienes (5-LOX). The biological effects of the test compounds
8a–c on eicosanoid synthesis/release were determined by
measuring the amounts of prostaglandin E2 and cysteinyl leu-
kotrienes (collectively referred to as a group of 5-LOX derived
metabolites LTC4, LTD4, and LTE4) secreted into the culture
medium of human brain cancer cells. Primary culture of ED
273b-BT human glioblastoma cells derived from patient was
established and characterized in our laboratory as previously
described [15]. Cells were seeded in 12-well plates (2 ꢄ
105cells/well) and cultured in Dulbecco’s modified Eagle’s
medium and F-12 nutrition mixture (Invitrogen, Grand Islands,
NY) supplemented with 10% heat-inactivated fetal calf serum,
100 units/mL penicillin, and 100 units/mL streptomycin at
37ꢁC in a humidified atmosphere of 5% CO2. The cells were
stimulated with the appropriate concentrations of the test com-
pounds and the positive controls celecoxib (LKT Laboratories,
St. Paul, MN) for COX-2 activity and NDGA (Cayman Chem-
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet