Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
PYRIDINYL-2-CYCLOPENTEN-1-ONES AS SELECTIVE
CYCLOOXYGENASE-2 INHIBITORS
BACKGROUND OF THE INVENTION
This invention relates to methods of treating
cyclooxygenase mediated diseases and certain pharmaceutical
compositions therefor.
Non-steroidal, antiinflammatory drugs exert most of their
antiinflammatory, analgesic and antipyretic activity and inhibit
hormone-induced uterine contractions and certain types of cancer
growth through inhibition of prostaglandin G/H synthase, also known as
cyclooxygenase. Initially, only one form of cyclooxygenase was known,
this corresponding to cyclooxygenase-1 (COX-1) or the constitutive
enzyme, as originally identified in bovine seminal vesicles. More
recently the gene for a second inducible form of cyclooxygenase,
cyclooxygenase-2 (COX-2) has been cloned, sequenced and
characterized initially from chicken, murine and human sources. This
enzyme is distinct from the COX-1 which has been cloned, sequenced
and characterized from various sources including the sheep, the mouse
and man. The second form of cyclooxygenase, COX-2, is rapidly and
readily inducible by a number of agents including mitogens, endotoxin,
hormones, cytokines and growth factors. As prostaglandins have both
physiological and pathological roles, we have concluded that the
constitutive enzyme, COX-1, is responsible, in large part, for
endogenous basal release of prostaglandins and hence is important in
their physiological functions such as the maintenance of gastrointestinal
integrity and renal blood flow. In contrast, we have concluded that the
inducible form, COX-2, is mainly responsible for the pathological
effects of prostaglandins where rapid induction of the enzyme would
occur in response to such agents as inflammatory agents, hormones,
growth factors, and cytokines. Thus, a selective inhibitor of COX-2
will have similar antiinflammatory, antipyretic and analgesic properties
to a conventional non-steroidal antiinflammatory drug, and in addition
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would inhibit hormone-induced uterine contractions and have potential
anti-cancer effects, but will have a diminished ability to induce some of
the mechanism-based side effects. In particular, such a compound
should have a reduced potential for gastrointestinal toxicity, a reduced
potential for renal side effects, a reduced effect on bleeding times and
possibly a lessened ability to induce asthma attacks in aspirin-sensitive
asthmatic subjects.
Furthermore, such a compound will also inhibit prostanoid-
induced smooth muscle contraction by preventing the synthesis of
contractile prostanoids and hence may be of use in the treatment of
dysmenorrhea, premature labour, asthma and eosinophil related
disorders. It will also be of use in the treatment of Alzheimer's disease,
for decreasing bone loss particularly in postmenopausal women (i.e.
treatment of osteoporosis) and for the treatment of glaucoma.
The potential utilities of selective cyciooxygenase-2
inhibitors are discussed in the following articles:
~ 1. John Vane, "Towards a better aspirin" in Nature, Vol. 367, pp.
215-216, 1994
~ 2. Bruno Battistini, Regina Botting and Y.S. Bakhle, " COX-1 and
COX-2: Toward the Development of More Selective NSAIDs" in
Drub News and Perspectives, Vol. 7, pp. 501-512, 1994.
~ 3. David B. Reitz and Karen Seibert, "Selective Cyclooxygenase
Inhibitors" in Annual Reports in Medicinal Chemistr,~ 3ames A.
Bristol, Editor, Vol. 30, pp. 179-188, 1995.
United States Patent 5,474,995 (December 12, 1995) and
World Patent Application 95/00501 (January 5, 1995) disclose
compounds represented by Formula A as being useful in the treatment
of COX-2 mediated diseases, by virtue of their selective inhibition of
COX-2 rather than COX-1. We have now discovered that a subset of
the compounds represented by A, in which -X-Y-Z- is -C(O)CH2CH2-
and R2 is pyridinyl or substituted pyridinyl show unexpectedly superior
selectivity for the inhibition of COX-2 over COX-1 and/or superior
potency as compared to the closest species disclosed in 95/00501. This
subset of compounds is the subject of the present invention and is
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represented by Formula I.
R~ S02R1
R2 ,,. Z R2 /
~(-Y
O
A I
Of the 150-plus specific compounds disclosed in U.S. Patent
5,474,995 and World Patent Application 95/00501 only 10 of them are
cyclopentenones, and none of these latter is a pyridinyl cyclopentenone.
Futhermore, among the variety of specific compounds disclosed, only
one of them contains a heterocyclic group in the place of R2, and that
group is quinoline, not pyridine.
SUMMARY OF THE INVENTION
The invention encompasses the novel compound of Formula
I as well as a method of treating COX-2 mediated diseases comprising
administration to a patient in need of such treatment of a non-toxic
1 S therapeutically effective amount of a compound of Formula I.
S02R~
R2 /
i
O
I
The invention also encompasses certain pharmaceutical
compositions for treatment of COX-2 mediated diseases comprising
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compounds of Formula I.
DETAILED DESCRIPTION OF THE INVENTION
The invention encompasses the novel compound of Formula
I as well as a method of treating COX-2 mediated diseases comprising
administration to a patient in need of such treatment of a non-toxic
therapeutically effective amount of a compound of Formula I
S02R~
R2 /
i
O
I
wherein:
R 1 is selected from the group consisting of
(a) CH3,
(b) NH2,
(c) NHC(O)CF3,
(d) NHCH3;
R2 is a mono-, di-, or tri-substituted pyridinyl, wherein the substituents
are chosen from the group consisting of
(a) hydrogen,
(b) halo,
(c) C1-(alkoxy,
(d) C1-(alkylthio,
(e) CN,
(f) C1-6alkyl,
(g) C 1-(fluoroalkyl,
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(h) N3
(i) -COOR3,
(j) hydroxy,
(k) -C(R3)(R4)-OH~
{l) -C 1 _6a1kY1_C02_R3,
(m) C1_6fluoroalkoxy;
R3 and R4 are independently chosen from the group consisting of
(a) hydrogen,
(b) C 1 _6alkyl,
or R3 and R4 together with the carbon to which they are attached form
a saturated monocyclic carbon ring of 3, 4, 5, 6 or 7 atoms.
A preferred sub-generic structure of compound I is that wherein R2 is a
mono-, di-, or trisubstituted 2-pyridinyl, and the remainder of the
i S substituents are as described for I.
Another preferred sub-generic structure of compound I is that wherein
R2 is a mono-, di-, or trisubstituted 3-pyridinyl, and the remainder of
the substituents are as described for I.
Yet another preferred embodiment of structure I is that wherein R 1 is
CH3 or NH2.
Another preferred embodiment of structure I is that wherein the
substituents on R2 are chosen from the group consisting of
(a) hydrogen,
{b) halo,
(c) C 1 _6alkoxy,
(d) C 1 _6alkylthio,
{e) C1_(alkyl,
(~ CF3.
(g) CN.
The following abbreviations have the indicated meanings:
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AA - arachidonic acid
Ac - acetyl
AIBN - 2.2--azobisisobutyronitrile
BHT - butylated hydroxytoluene
Bn - benzyl
dba - dibenzylideneacetone
DMAP - 4-(dimethylamino)pyridine
DMF - N,N-dimethylformamide
DMSO - dimethyl sulfoxide
EDTA - ethylenediaminetetraacetic acid
Et3N - triethylamine
HBSS - Hanks balanced salt solution
HEPES - N-[2-Hydroxyethyl]piperazine-N1-[2-
ethanesulfonic acid]
HWB - human whole blood
HI~V~S = potassium hexamethyldisilazane
LDA - lithium diisopropylamide
LPS - lipopolysaccharide
MMPP - magnesium monoperoxyphthalate
Ms - methanesulfonyl = mesyl
Ms0 - methanesulfonate = mesylate
NBS - N-bromosuccinimide
NCS - N-chlorosuccinimide
NIS - N-iodosuccinimide
NMP - N-methylpyrrolidone
NSA117 - non-steroidal anti-inflammatory
drug
PCC - pyridinium chlorochromate
PDC - pyridinium dichromate
PEG - polyethyleneglycol
Ph - phenyl
r.t. - room temperature
rac. - racemic
Tf - trifluoromethanesulfonyl = triflyl
Tf0 - trifluoromethanesulfonate = triflate
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THF - tetrahydrofuran
TLC - thin layer chromatography
Ts - p-toluenesulfonyl = tosyl
Ts0 - p-toluenesulfonate =
tosylate
Tz - 1H (or 2H)-tetrazol-5-yl
SO~VIe - methyl sulfone
SO~VH2 - sulfonamide
Alkyl group abbreviations
Me - methyl
Et - ethyl
n-Pr - normal propyl
i-Pr - isopropyl
n-Bu - normal butyl
i-Bu - isobutyl
s-Bu - secondary butyl
t-Bu - tertiary butyl
c-Pr - cyclopropyl
c-Bu - cyclobutyl
c-Pen - cyclopentyl
c-Hex - cyclohexyl
Dose Abbreviations
bid - bis in die = twice daily
qid - quater in die = four times a day
tid - ter in die = three times a day
For purposes of this specification alkyl is defined to include
linear, branched and cyclic stuctures, with the indicated number of
carbon atoms. Examples of alkyl are methyl, ethyl, propyl, s- and t-
butyl, butyl, pentyl, hexyl, 1,1-dimethylethyl, cyclopropyl, cyclobutyl,
cyclohexylmethyl and the like. Similarly, alkoxy and alkylthio mean
linear, branched and cyclic stuctures, with the indicated number of
carbon atoms.
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For purposes of this specification fluoroalkyl means alkyl
groups of the indicated number of carbon atoms in which one hydrogen
or more is replaced by fluorine. Examples are -CF3, -CH2CH2F,
-CH2CF3, c-Pr-F5, c-Hex-F11 and the like. Similarly, fluoroalkoxy
means linear, branched and cyclic stuctures, with the indicated number
of carbon atoms.
For purposes of this specification, in situations in which a
term occurs two or more times, the definition of the term in each
occurrence is independent of the definition in each additional
occurrence.
For purposes of this specification halo means F, Cl, Br, or
I.
In another embodiment, the invention encompasses
pharmaceutical compositions for inhibiting COX-2 and for treating
COX-2 mediated diseases as disclosed herein comprising a
pharmaceutically acceptable carrier and non-toxic therapeutically
effective amount of a compound of formula I as described above.
In yet another embodiment, the invention encompasses a
method of inhibiting cyclooxygenase and treating cyclooxygenase
mediated diseases, advantageously treated by an active agent that
selectively inhibits COX-2 in preference to COX-1 as disclosed herein
comprising:
administration to a patient in need of such treatment of a non-toxic
therapeutically effective amount of a compound of Formula I as
disclosed herein.
Optical Isomers - Diastereomers - Geometric Isomers
Some of the compounds described herein contain one or
more asymmetric centres and may thus give rise to diastereomers and
optical isomers. The present invention is meant to comprehend such
possible diastereomers as well as their racemic and resolved,
enantiomerically pure forms and pharmaceutically acceptable salts
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thereof.
Some of the compounds described herein contain olefinic
double bonds, and unless specified otherwise, are meant to include both
E and Z geometric isomers.
Salts
The pharmaceutical compositions of the present invention
comprise a compound of Formula I as an active ingredient or a
pharmaceutically acceptable salt, thereof, and may also contain a
pharmaceutically acceptable carrier and optionally other therapeutic
ingredients. The term "pharmaceutically acceptable salts" refers to salts
prepared from pharmaceutically acceptable non-toxic bases including
inorganic bases and organic bases. Salts derived from inorganic bases
include aluminum, ammonium, calcium, copper, ferric, ferrous,
lithium, magnesium, manganic salts, manganous, potassium, sodium,
zinc, and the like. Particularly preferred are the ammonium, calcium,
magnesium, potassium, and sodium salts. Salts derived from
pharmaceutically acceptable organic non-toxic bases include salts of
primary, secondary, and tertiary amines, substituted amines including
naturally occurring substituted amines, cyclic amines, and basic ion
exchange resins, such as arginine, betaine, caffeine, choline,
N,N--dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol,
2-dimethylaminoethanoi, ethanoiamine, ethylenediamine,
N-ethylmorpholine, N-ethylpiperidine, N-methylglucamine, glucamine,
glucosamine, histidine, hydrabamine, N-(2-hydroxyethyl)piperidine, N-
(2-hydroxyethyl)pyrrolidine, isopropylamine, lysine, methylglucamine,
morpholine, piperazine, piperidine, polyamine resins, procaine, purines,
theobromine, triethylamine, trimethyiamine, tripropylamine,
tromethamine, and the like.
When the compound of the present invention is basic, salts
may be prepared from pharmaceutically acceptable non-toxic acids,
including inorganic and organic acids. Such acids include acetic, adipic,
aspartic, 1,5-naphthalenedisulfonic, benzenesulfonic, benzoic,
camphorsulfonic, citric, 1,2-ethanedisulfonic, ethanesulfonic,
ethylenediaminetetraacetic, fumaric, glucoheptonic, giuconic, glutamic,
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hydriodic, hydrobromic, hydrochloric, isethionic, lactic, malefic, malic,
mandelic, methanesulfonic, mucic, 2-naphthalenesulfonic, nitric, oxalic,
pamoic, pantothenic, phosphoric, pivalic, propionic, salicylic, stearic,
succinic, sulfuric, tartaric, p-toluenesulfonic acid, undecanoic, 10-
undecenoic, and the like. Particularly preferred are citric,
hydrobromic, hydrochloric, malefic, methanesulfonic, phosphoric,
sulfuric and tartaric acids.
It will be understood that in the discussion of methods of
treatment which follows, references to the compounds of Formula I are
meant to also include the pharmaceutically acceptable salts.
Utilities
The Compound of Formula I is useful for the relief of pain,
fever and inflammation of a variety of conditions including rheumatic
fever, symptoms associated with influenza or other viral infections,
common cold, low back and neck pain, dysmenorrhea, headache,
toothache, sprains and strains, myositis, neuralgia, synovitis, arthritis,
including rheumatoid arthritis, degenerative joint diseases
(osteoarthritis), gout and ankylosing spondylitis, bursitis, burns,
injuries, following surgical and dental procedures. In addition, such a
compound may inhibit cellular neoplastic transformations and metastic
tumour growth and hence can be used in the treatment of cancer.
Compound 1 may also be of use in the treatment and/or prevention of
cyclooxygenase-mediated proliferative disorders such as may occur in
diabetic retinopathy and tumour angiogenesis.
Compound I will also inhibit prostanoid-induced smooth
muscle contraction by preventing the synthesis of contractile prostanoids
and hence may be of use in the treatment of dysmenorrhea, premature
labour, asthma and eosinophil related disorders. It will also be of use in
the treatment of Alzheimer's disease, for decreasing bone loss
particularly in postmenopausal women (i.e. treatment of osteoporosis)
and for treatment of glaucoma.
By virtue of its high inhibitory activity against COX-2
and/or its specificity for COX-2 over COX-1, compound I will prove
useful as an alternative to conventional NSAID'S, particularly where
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such non-steroidal antiinflammatory drugs may be contra-indicated such
as in patients with peptic ulcers, gastritis, regional enteritis, ulcerative
colitis, diverticulitis or with a recurrent history of gastrointestinal
lesions; GI bleeding, coagulation disorders including anaemia such as
hypoprothrombinemia, haemophilia or other bleeding problems; kidney
disease; those prior to surgery or taking anticoagulants.
Pharmaceutical Compositions
For the treatment of any of these cyclooxygenase mediated
diseases compound I may be administered orally, topically, parenterally,
by inhalation spray or rectally in dosage unit formulations containing
conventional non-toxic pharmaceutically acceptable carriers, adjuvants
and vehicles. The term parenteral as used herein includes subcutaneous
injections, intravenous, intramuscuiar, intrasternal injection or infusion
techniques. In addition to the treatment of warm-blooded animals such
as mice, rats, horses, cattle, sheep, dogs, cats, etc., the compound of the
invention is effective in the treatment of humans.
As indicated above, pharmaceutical compositions for
treating COX-2 mediated diseases as defined may optionally include one
or more ingredients as listed above.
The pharmaceutical compositions containing the active
ingredient may be in a form suitable for oral use, for example, as
tablets, troches, lozenges, aqueous or oily suspensions, dispersible
powders or granules, emulsions, hard or soft capsules, or syrups or
elixirs. Compositions intended for oral use may be prepared according
to any method known to the art for the manufacture of pharmaceutical
compositions and such compositions may contain one or more agents
selected from the group consisting of sweetening agents, flavouring
agents, colouring agents and preserving agents in order to provide
pharmaceutically elegant and palatable preparations. Tablets contain the
active ingredient in admixture with non-toxic pharmaceutically
acceptable excipients which are suitable for the manufacture of tablets.
These excipients may be for example, inert diluents, such as calcium
carbonate, sodium carbonate, lactose, calcium phosphate or sodium
phosphate; granulating and disintegrating agents, for example, corn
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starch, or aiginic acid; binding agents, for example starch, gelatin or
acacia, and lubricating agents, for example, magnesium stearate, stearic
acid or talc. The tablets may be uncoated or they may be coated by
known techniques to delay disintegration and absorption in the
gastrointestinal tract and thereby provide a sustained action over a
longer period. For example, a time delay material such as glyceryl
monostearate or glyceryl distearate may be employed. They may also
be coated by the technique described in the U.S. Patent 4,256,108;
4,166,452; and 4,265,874 to form osmotic therapeutic tablets for
control release.
Formulations for oral use may also be presented as hard
gelatin capsules wherein the active ingredient is mixed with an inert
solid diluent, for example, calcium carbonate, calcium phosphate or
kaolin, or as soft gelatin capsules wherein the active ingredients is mixed
with water or miscible solvents such as propylene glycol, PEGs and
ethanol, or an oil medium, for example peanut oil, liquid paraffin, or
olive oil.
Aqueous suspensions contain the active material in
admixture with excipients suitable for the manufacture of aqueous
suspensions. Such excipients are suspending agents, for example sodium
carboxymethylcellulose, methylcellulose, hydroxypropylmethycellulose,
sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia;
dispersing or wetting agents may be a naturally-occurring phosphatide,
for example lecithin, or condensation products of an alkylene oxide with
fatty acids, for example polyoxyethylene stearate, or condensation
products of ethylene oxide with long chain aliphatic alcohols, for
example heptadecaethyleneoxycetanol, or condensation products of
ethylene oxide with partial esters derived from fatty acids and a hexitol
such as polyoxyethylene sorbitol monooleate, or condensation products
of ethylene oxide with partial esters derived from fatty acids and hexitol
anhydrides, for example polyethylene sorbitan monooleate. The
aqueous suspensions may also contain one or more preservatives, for
example ethyl, .or n-propyl, p-hydroxybenzoate, benzyl alcohol, one or
more colouring agents, one or more flavouring agents, and one or more
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sweetening agents, such as sucrose, saccharin or aspartame.
Oily suspensions may be formulated by suspending the
active ingredient in a vegetable oil, for example arachis oil, olive oil,
sesame oil or coconut oil, or in mineral oil such as liquid paraffin. The
oily suspensions may contain a thickening agent, for example beeswax,
hard paraffin or cetyl alcohol. Sweetening agents such as those set forth
above, and flavouring agents may be added to provide a palatable oral
preparation. These compositions may be preserved by the addition of
an anti-oxidant such as ascorbic acid.
Dispersible powders and granules suitable for preparation
of an aqueous suspension by the addition of water provide the active
ingredient in admixture with a dispersing or wetting agent, suspending
agent and one or more preservatives. Suitable dispersing or wetting
agents and suspending agents are exemplified by those already
mentioned above. Additional excipients, for example sweetening,
flavouring and colouring agents, may also be present.
The pharmaceutical compositions of the invention may also
be in the form of an oil-in-water emulsions. The oily phase may be a
vegetable oil, for example olive oil or arachis oil, or a mineral oil, for
example liquid paraffin or mixtures of these. Suitable emulsifying
agents may be naturally-occurring phosphatides, for example soy bean,
lecithin, and esters or partial esters derived from fatty acids and hexitol
anhydrides, for example sorbitan monooleate, and condensation
products of the said partial esters with ethylene oxide, for example
polyoxyethylene sorbitan monooleate. The emulsions may also contain
sweetening and flavouring agents.
Syrups and elixirs may be formulated with sweetening
agents, for example glycerol, propylene glycol, sorbitol or sucrose.
Such formulations may also contain a demulcent, a preservative and
flavouring and colouring agents. The pharmaceutical compositions may
be in the form of a sterile injectable aqueous or oleagenous suspension.
This suspension may be formulated according to the known art using
those suitable dispersing or wetting agents and suspending agents which
have been mentioned above. The sterile injectable preparation may also
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be a sterile injectable solution or suspension in a non-toxic parenterally-
acceptable diluent or solvent, for example as a solution in 1,3-butane
diol. Among the acceptable vehicles and solvents that may be employed
are water, Ringer's solution and isotonic sodium chloride solution.
S Cosolvents such as ethanol, propylene glycol or polyethylene glycols
may also be used. In addition, sterile, fixed oils are conventionally
employed as a solvent or suspending medium. For this purpose any
bland fixed oil may be employed including synthetic mono- or
diglycerides. In addition, fatty acids such as oleic acid find use in the
preparation of injectables.
Compound of Formula I may also be administered in the
form of a suppositories for rectal administration of the drug. These
compositions can be prepared by mixing the drug with a suitable non-
irritating excipient which is solid at ordinary temperatures but liquid at
the rectal temperature and will therefore melt in the rectum to release
the drug. Such materials are cocoa butter and polyethylene glycols.
For topical use, creams, ointments, gels, solutions or
suspensions, etc., containing the compound of Formula I are employed.
(For purposes of this application, topical application shall include mouth
washes and gargles.) Topical formulations may generally be comprised
of a pharmaceutical carrier, cosolvent, emulsifier, penetration enhancer,
preservative system, and emollient.
Dose Ranges
Dosage levels of the order of from about 0.01 mg to about
140 mg/kg of body weight per day are useful in the treatment of the
above-indicated conditions, or alternatively about 0.5 mg to about 7 g
per patient per day. For example, inflammation may be effectively
treated by the administration of from about 0.01 to 50 mg of the
compound per kilogram of body weight per day, or alternatively about
0.5 mg to about 3.5 g per patient per day.
The amount of active ingredient that may be combined with
the carrier materials to produce a single dosage form will vary
depending upon the host treated and the particular mode of
administration. For example, a formulation intended for the oral
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administration of humans may contain from 0.5 mg to 5 g of active
agent compounded with an appropriate and convenient amount of
carrier material which may vary from about 5 to about 95 percent of
the total composition. Dosage unit forms will generally contain between
from about 1 mg to about 500 mg of an active ingredient, typically 25
mg, 50 mg, 100 mg, 200 mg, 300 mg, 400 mg, 500 mg; 600 mg, 800
mg, or 1000 mg.
It will be understood, however, that the specific dose level
for any particular patient will depend upon a variety of factors
including the age, body weight, general health, sex, diet, time of
administration, route of administration, rate of excretion, drug
combination and the severity of the particular disease undergoing
therapy.
Combinations with Other Drugs
Similarly, compound of Formula I, will be useful as a
partial or complete substitute for conventional NSAID'S in preparations
wherein they are presently co-administered with other agents or
ingredients. Thus in further aspects, the invention encompasses
pharmaceutical compositions for treating COX-2 mediated diseases as
defined above comprising a non-toxic therapeutically effective amount
of the compound of Formula I as defined above and one or more
ingredients such as another pain reliever including acetaminophen or
phenacetin; a potentiator including caffeine; an H2-antagonist, aluminum
or magnesium hydroxide, simethicone, a decongestant including
phenylephrine, phenylpropanolamine, pseudophedrine, oxymetazoline,
ephinephrine, naphazoline, xylometazoline, propylhexedrine, or levo-
desoxyephedrine; an antiitussive including codeine, hydrocodone,
caramiphen, carbetapentane, or dextramethorphan; a prostaglandin
including misoprostol, enprostil, rioprostil, ornoprostol or rosaprostol:
a diuretic; a sedating or non-sedating antihistamine. In addition the
invention encompasses a method of treating cyclooxygenase mediated
diseases comprising: administration to a patient in need of such
treatment a non-toxic therapeutically effective amount of the compound
of Formula I, optionally co-administered with one or more of such
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ingredients as listed immediately above.
Methods of Synthesis
The compounds of the present invention can be prepared
according to the following methods.
Method A
Cyclopentenone (II) may be halogenated with bromine or
iodine followed by treatment with a base to give III (see Organic
Syntheses 61 65). An appropriately substituted pyridine boronic acid
may then be added via a palladium-catalyzed coupling reaction to form
IV. 4-Bromothioanisole may be metalated with nBuLi or magnesium,
and then treated with IV to give the alcohol V. Oxidation with allylic
transposition may then be accomplished using an oxidant such as PDC to
give cyclopentenone VI. Sulfide oxidation using an oxidant such as
MMPP or mCPBA then provides sulfone Ia. Alternatively, VI may be
converted to sulfonamide Ib as described in U.S. Patent 5,474,995.
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Method A:
O O R2_g~OR)2 O
X Pd° R2 ~ SMe
base
II III IV
M
X=Br, I
M = Li, Mg
S02Me / SMe SMe
HO
PDC
I
~R2 ~R2 ' 2
O O R
VI
la ref: V
S02NH2
O
Ib
Method B
S To bromocyclopentenone IIIa is added lithio or magnesium
thioanisole to give tertiary alcohol VII. Oxidation with a reagent such
as PDC then provides the ketone VIII. The sulfide may be oxidized at
this point using an oxidant such as MMPP or mCPBA to give the sulfone
IX. Palladium-catalyzed coupling of an appropriately substituted
pyridinyl boronic acid then provides Ia.
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SMe / SMe / SMe
O
M
Br Br ~ Br
M = Li, Mg VII O Vill
Ilia
S02Me
R2B(OR)2 SO Me
" ~ 2
R2 pdo w
O
la base Br
O
IX
Method C
An appropriately substituted methylpyridine X may be
deprotonated with an alkyl lithium reagent and the resulting anion added
to a diamide XI to provide the ketoamide XII. Cyclization of this
intermediate with a base such as DBU provides the enol XIII which can
then be converted to the triflate XIV. A palladium-catalyzed coupling
reaction with 4-(methylthio)phenylboronic acid in the presence of an
appropriate base then provides sulfide VI which can be oxidized to give
the sulfone Ia or the sulfonamide Ib as described in Method A.
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O
1) n-BuLi
R2CH R2
r
X 2) "N ~ N, XII
XI O
DBU
OTf OH
i-Pr2EtN/ Tf20
R2 . ~ R2
O XIV
SMe XIII
Pd (0)
Base
B(OH)2
SMe Me
MMPP
2
R
O VI O la
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Representative Compounds
Table I illustrates compounds of formula I, which are
representative of the present invention.
Table I
EXAMPLE
S02Me
1
S02Me
CI
S02Me
Br
S02Me
4
Me
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S02Me
OMe
S02Me
CF3
~,02Me
7
N
S02Me
F
Me
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EXAMPLE
S02Me
9
S02Me
CI
°02Me
11
S02Me
12
Br
S02Me
13
CF3
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S02Me
14
OMe
S02Me
CF3 15
S02Me
16
S02Me
17
Me
S02Me
CF3 18
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Assays for Determining Biological Activity
The compound of Formula I can be tested using the
following assays to determine their COX-2 inhibiting activity.
INHIBITION OF CYCLOOXYGENASE ACTIVITY
Compounds are tested as inhibitors of cyclooxygenase
activity in whole cell cyclooxygenase assays. Both of these assays
measure prostaglandin E2 synthesis in response to AA, using a
radioimmunoassay. Cells used for these assays are human osteosarcoma
143 cells (which specifically express COX-2) and human U-937 cells
(which specifically express COX-1). In these assays, 100% activity is
defined as the difference between prostaglandin E2 synthesis in the
absence and presence of arachidonate.
Whole Cell Assay
For cyclooxygenase assays, osteosarcoma cells are cultured
in 1 mL of media in 24-well multidishes (Nunclon) until confluent (1-2
x 105 cells/well). U-937 cells are grown in spinner flasks and
resuspended to a final density of 1.5 x 106 cells/mL in 24-well
multidishes (Nunclon). Following washing and resuspension of
osteosarcoma and U-937 cells in 1 mL of HBSS, 1 NI, of a DMSO
solution of test compound or DMSO vehicle is added, and samples
gently mixed. All assays are performed in triplicate. Samples are then
incubated for 5 or 15 minutes at 37°C, prior to the addition of AA. AA
(peroxide-free, Cayman Chemical) is prepared as a 10 mM stock
solution in ethanol and further diluted 10-fold in HBSS. An aliquot of
10 NL of this diluted solution is added to the cells to give a final AA
concentration of 10 p.M. Control samples are incubated with ethanol
vehicle instead of AA. Samples are again gently mixed and incubated
for a further 10 min. at 37°C. For osteosarcoma cells, reactions are
then stopped by the addition of 100 pL, of 1N HCI, with mixing and by
the rapid removal of the solution from cell monolayers. For U-937
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cells, reactions are stopped by the addition of 100 ~I. of 1N HCI, with
mixing. Samples are then neutralized by the addition of 100 NL of 1N
NaOH and PGE2 levels measured by radioimmunoassay.
Whole cell assays for COX-2 and COX-1 using CHO transfected cell
lines
Chinese hamster ovary (CHO) cell lines which have been
stably transfected with an eukaryotic expression vector pCDNAIII
containing either the human COX-1 or COX-2 cDNA's are used for the
assay. These cell lines are referred to as CHO [hCOX-1] and CHO
[hCOX-2], respectively. For cyclooxygenase assays, CHO[hCOX-1]
cells from suspension cultures and CHO[hCOX-2] cells prepared by
trypsinization of adherent cultures are harvested by centrifugation (300
x g, 10 min) and washed once in HBSS containing 15 mM HEPES, pH
7.4, and resuspended in HBSS, 15 mM HEPES, pH 7.4, at a ceU
concentration of 1.5 x 106 cells/ml. Drugs to be tested are dissolved in
DMSO to 66.7-fold the highest test drug concentration. Compounds are
typically tested at 8 concentrations in duplicate using serial 3-fold serial
dilutions in DMSO of the highest drug concentration. Cells (0.3 x 106
cells in 200 E.~l) are preincubated with 3 Nl of the test drug or DMSO
vehicle for 15 min at 37°C. Working solutions of peroxide-free AA
(5.5 NM and 110 NM AA for the CHO [hCOX-1] and CHO [COX-2]
assays, respectively) are prepared by a 10-fold dilution of a
concentrated AA solution in ethanol into HB S S containing 15 mM
HEPES, pH 7.4. Cells are then challenged in the presence or absence of
drug with the AA/HBSS solution to yield a final concentration of 0.5
E,iM AA in the CHO[hCOX-1] assay and a final concentration of 10 ~M
AA in the CHO[hCOX-2] assay. The reaction is terminated by the
addition of 10 x.11 1 N HCl followed by neutralization with 20 ~tl of 0.5
N NaOH. The samples are centrifuged at 300 x g at 4°C for 10 min,
and an aliquot of the clarified supernatant is appropriately diluted for
the determination of PGE2 levels using an enzyme-linked immunoassay
for PGE2 (Correlate PGE2 enzyme immunoassay kit, Assay Designs,
Inc.). Cyclooxygenase activity in the absence of test compounds is
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determined as the difference in PGE2 levels of cells challenged with AA
versus the PGE2 levels in cells mock-challenged with ethanol vehicle.
Inhibition of PGE2 synthesis by test compounds is calculated as a
percentage of the activity in the presence of drug versus the activity in
the positive control samples.
Assay of COX-1 Activity from U937 cell microsomes
U 937 cells are pelleted by centrifugation at 500 x g for 5
min and washed once with phosphate-buffered saline and repelleted.
Cells are resuspended in homogenization buffer consisting of 0.1 M
Tris-HCI, pH 7.4, 10 mM EDTA, 2 pg/mI leupeptin, 2 ~tg/ml soybean
trypsin inhibitor, 2 pg/ml aprotinin and 1 mM phenyl methyl sulfonyl
fluoride. The cell suspension is sonicated 4 times for 10 sec and is
centrifuged at 10,000 x g for 10 min at 4°C. The supernatant is
centrifuged at 100,000 x g for 1 hr at 4°C. The 100,000 x g
microsomal pellet is resuspended in 0.1 M Tris-HCI, pH 7.4, 10 mM
EDTA to approximately 7 mg protein/ml and stored at -80°C.
Microsomal preparations are thawed immediately prior to
use, subjected to a brief sonication, and then diluted to a protein
concentration of 125 ~tg/ml in 0.1 M Tris-HCl buffer, pH 7.4 containing
10 mM EDTA, 0.5 mM phenol, 1 mM reduced glutathione and 1 pM
hematin. Assays are performed in duplicate in a final volume of 250 Ell.
Initially, 5 E,il of DMSO vehicle or drug in DMSO are added to 20 E.~l of
0.1 M Tris-HCl buffer, pH 7.4 containing 10 mM EDTA in wells of a
96-deepwell polypropylene titre plate. 200 ~.~I of the microsomal
preparation are then added and pre-incubated for 15 min at room
temperature before addition of 25 ~.~1 of 1 M arachidonic acid in 0.1 M
Tris-HCI and 10 mM EDTA, pH 7.4. Samples are incubated for 40 min
at room temperature and the reaction is stopped by the addition of 25 E.il
of 1 N HCI. Samples are neutralized with 25 Eal of 1 N NaOH prior to
quantitation of PGE2 content by radioimmunoassay (Dupont-NEN or
Amersham assay kits). Cyclooxygenase activity is defined as the
difference between PGE2 levels in samples incubated in the presence of
arachidonic acid and ethanol vehicle.
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Assay of the activit~~purified human COX-2
The enzyme activity is measured using a chromogenic assay
based on the oxidation of N,N,N',N'-tetramethyl-p-phenylenediamine
(TMPD) during the reduction of PGG2 to PGH2 by COX-2 (Copeland et
al. (1994) Proc. Natl. Acad. Sci. 91, 11202-11206).
Recombinant human COX-2 is purified from Sf9 cells as
previously described (Percival et al (1994) Arch. Biochem. Biophys. 15,
1 I1-118). The assay mixture (180 pL,) contains 100 mM sodium
phosphate, pH 6.5, 2 mM genapol X-100, 1 NM hematin, 1 mg/ml
gelatin , 80-100 units of purified enzyme (One unit of enzyme is defined
as the amount of enzyme required to produce an O.D. change of
0.001/min at 610 nm) and 4 E.~L of the test compound in DMSO. The
mixture is pre-incubated at room temperature (22°C) for 15 minutes
1 S prior to initiation of the enzymatic reaction by the addition of 20 NI, of
a sonicated solution of 1 mM AA and 1 mM TMPD in assay buffer
(without enzyme or hematin). The enzymatic activity is measured by
estimation of the initial velocity of TMPD oxidation over the first 36 sec
of the reaction. A non-specific rate of oxidation is observed in the
absence of enzyme (0.007 - 0.010 O.D. /min) and is subtracted before
the calculation of the °!o inhibition. iCSO values are derived from 4-
parameter least squares non-linear regression analysis of the log-dose vs
°lo inhibition plot.
HUMAN WHOLE BLOOD ASSAY
Rationale
Human whole blood provides a protein and cell-rich milieu
appropriate for the study of biochemical efficacy of anti-inflammatory
compounds such as selective COX-2 inhibitors. Studies have shown that
normal human blood does not contain the COX-2 enzyme. This is
consistent with the observation that COX-2 inhibitors have no effect on
PGE2 production in normal blood. These inhibitors are active only
after incubation of human whole blood with LPS, which induces COX-
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2. This assay can be used to evaluate the inhibitory effect of selective
COX-2 inhibitors on PGE2 production. As well, platelets in whole
blood contain a large amount of the COX-1 enzyme. Immediately
following blood clotting, platelets are activated through a thrombin-
mediated mechanism. This reaction results in the production of
thromboxane B2 (TxB2) via activation of COX-1. Thus, the effect of
test compounds on TxB2 levels following blood clotting can be
examined and used as an index for COX-1 activity. Therefore, the
degree of selectivity by the test compound can be determined by
measuring the levels of PGE2 after LPS induction (COX-2) and TxB2
following blood clotting (COX-1 ) in the same assay.
Method
A. COX-2 (LPS-induced PGE2 production)
Fresh blood is collected in heparinized tubes by
venipuncture from both male and female volunteers. The subjects have
no apparent inflammatory conditions and have not taken any NSAIDs
for at least 7 days prior to blood collection. Plasma is immediately
obtained from a 2mL blood aliquot to use as blank (basal levels of
PGE2). The remaining blood is incubated with LPS ( 100 pg/ml final
concentration, Sigma Chem, #L-2630 from E. coli; diluted in 0.1% BSA
(Phosphate buffered saline) for 5 minutes at room temperature. Five
hundred NL, aliquots of blood are incubated with either 2~L of vehicle
(DMSO) or 2E,~L of a test compound at final concentrations varying
from lOnM to 30EtM for 24 hours at 37°C. At the end of the
incubation, the blood is centrifuged at 12,000 x g for 5 minutes to
obtain plasma. A 100E.~L aliquot of plasma is mixed with 400NI. of
methanol for protein precipitation. The supernatant is obtained and is
assayed for PGE2 using a radioimmunoassay kit (Amersham, RPA#530)
after conversion of PGE2 to its methyl oximate derivative according to
the manufacturer's procedure.
B. COX-1 (Clotting-induced TxB2 production)
Fresh blood is collected into vacutainers containing no
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anticoagulants. Aliquots of SOOpL, are immediately transferred to
siliconized microcentrifuge tubes preloaded with 2N.L of either DMSO
or a test compound at final concentrations varying from lOnM to 30E.~M.
The tubes are vortexed and incubated at 37°C for 1 hour to allow
blood
to clot. At the end of incubation, serum is obtained by centrifugation
(12,000 x g for 5 min.). A 100NI. aliquot of serum is mixed with
400~.L of methanol for protein precipitation. The supernatant is
obtained and is assayed for TxB2 using a enzyme immunoassay kit
(Cayman, #519031) according to the manufacturer's instruction.
RAT PAW EDEMA ASSAY
rot coI
Male Sprague-Dawley rats ( 1 SO-200 g) are fasted overnight
and are given, po, either vehicle (1% methocel or 5% Tween 80) or a
1 S test compound. One hr later, a line is drawn using a permanent marker
at the level above the ankle in one hind paw to define the area of the
paw to be monitored. The paw volume (Vv) is measured using a
plethysmometer (Ugo-Basile, Italy) based on the principle of water
displacement. The animals are then injected subplantarly with 50 ~,1 of
1 % carrageenan solution in saline (FMC Corp, Maine) into the paw
using an insulin syringe with a 25-gauge needle (i.e. 500 ~.g carrageenan
per paw). Three hr later, the paw volume (V3) is measured and the
increases in paw volume (V3 - Vo) are calculated. The animals are
sacrificed by C02 asphyxiation and the absence or presence of stomach
lesions scored. Data is compared with the vehicle-control values and
percent inhibition calculated. All treatment groups are coded to
eliminate observer bias.
NSAID-INDUCED GASTROPATHY IN RATS
Ra 'on a
The major side effect of conventional NSAIDs is their
ability to produce gastric lesions in man. This action is believed to be
caused by inhibition of COX-1 in the gastrointestinal tract. Rats are
particularly sensitive to the actions of NSAIDs. In fact, rat models have
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been used commonly in the past to evaluate the gastrointestinal side
effects of current conventional NSAIDs. In the present assay, NSAID-
induced gastrointestinal damage is observed by measuring fecal 51 Cr
excretion after systemic injection of SlCr-labeled red blood cells. Fecal
S SICr excretion is a well-established and sensitive technique to detect
gastrointestinal integrity in animals and man.
Methods
Male Sprague Dawley rats ( 150 - 200 g) are administered
orally a test compound either once (acute dosing) or b.i.d. for 5 days
(chronic dosing). Immediately after the administration of the last dose,
the rats are injected via a tail vein with 0.5 mL of 5lCr-labeled red
blood cells from a donor rat. The animals are placed individually in
metabolism cages with food and water ad lib. Feces are collected for a
48 h period and 51 Cr fecal excretion is calculated as a percent of total
injected dose. SlCr-labeled red blood cells are prepared using the
following procedures. Ten mL of blood is collected in heparinized
tubes via the vena cava from a donor rat. Plasma is removed by
centrifugation and replenished with equal volume of HBSS. The red
blood cells are incubated with 400p. Ci of sodium 51 chromate for 30
min. at 37°C. At the end of the incubation, the red blood cells are
washed twice with 20 mL HB SS to remove free sodium S 1 chromate.
The red blood cells are finally reconstituted in 10 mL HBSS and 0.5 mL
of the solution (about 20~, Ci) is injected per rat.
PROTEIN-LOSING GASTROPATHY IN SQUIRREL MONKEYS
ati a
Protein-losing gastropathy (manifested as appearance of
circulating cells and plasma proteins in the GI tract) is a significant and
dose-limiting adverse response to standard non-steroidal anti-
inflammatory drugs (NSAIDs). This can be quantitatively assessed by
intravenous administration of SlCrCl3 solution. This isotopic ion can
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avidly bind to cell and serum globins and cell endoplasmic reticulum.
Measurement of radioactivity appearing in feces collected for 24 h after
administration of the isotope thus provides a sensitive and quantitative
index of protein-losing gastropathy.
Methods
Groups of male squirrel monkeys (0.8 to 1.4 kg) are
treated by gavage with either 1% methocell or 5% Tween 80 in H20
vehicles, (3mL/kg b.i.d.) or test compounds at doses from 1 - 100
mg/kg b.i.d. for 5 days. Intravenous 51 Cr (5~. Ci/kg in 1 ml/kg
phosphate buffer saline (PBS)) is administered 1 h after the last
drug/vehicle dose, and feces collected for 24 h in a metabolism cage and
assessed for excreted SlCr by gamma-counting. Venous blood is
sampled 1 h and 8 h after the last drug dose, and plasma concentrations
of drug measured by RP-HPLC.
PHARMACOHINETIC~ TN RATS
Per Os Pharmacokinetics in Rats
The animals are housed, fed and cared for according to the
Guidelines of the Canadian Council on Animal Care.
Male Sprague Dawley rats (325-375 g) are fasted overnight
prior to each PO blood level study.
The rats are placed in the restrainer one at a time and the
box firmly secured. The zero blood sample is obtained by nicking a
small ( 1 mm or less) piece off the tip of the tail. The tail is then stroked
with a firm but gentle motion from the top to the bottom to milk out the
blood. Approximately 1 mL of blood is collected into a heparinized
vacutainer tube.
Compounds are prepared as required, in a standard dosing
volume of lOmL/kg, and administered orally by passing a 16 gauge, 3"
gavaging needle into the stomach.
Subsequent bleeds are taken in the same manner as the zero
bleed except that there is no need to nick the tail again. The tail is
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cleaned with a piece of gauze and milked/stroked as described above into
the appropriately labelled tubes.
Immediately after sampling, blood is centrifuged,
separated, put into clearly marked vials and stored in a freezer until
analysed.
Typical time points for determination of rat blood levels
after PO dosing are:
0, l5min, 30min, 1h, 2h, 4h, 6h
After the 4 hr time point bleed, food is provided to the rats
ad libitum. Water is provided at all times during the study.
Vehicles:
The following vehicles may be used in PO rat blood level
determinations:
PEG 200/300/400: restricted to 2 mL/kg
Methocel 0.5% - 1.0%: lOmL/kg
Tween 80: lOmL/kg
Compounds for PO blood levels can be in suspension form.
For better dissolution, the solution can be placed in a sonicator for
approximately 5 minutes.
For analysis, aliquots are diluted with an equal volume of
acetonitrile and centrifuged to remove protein precipitate. The
supernatant is injected directly onto a C-18 HPLC column with UV
detection. Quantitation is done relative to a clean blood sample spiked
with a known quantity of drug. Bioavailability (F) is assessed by
comparing area under the curve (AUC) i.v. versus p.o.
F - AU o x DO iv x 100%
AUCiv DOSEpo
Clearance rates are calculated from the following relation:
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CL = DOSEiv(mglkg)
AUCiv
The units of CL are mL/h~kg (milliliters per hour kilogram)
Intravenous Pharmacokinetics in Rats
The animals are housed, fed and cared for according to the
Guidelines of the Canadian Council on Animal Care.
Male Sprague Dawley (325-375 g) rats are placed in plastic
shoe box cages with a suspended floor, cage top, water bottle and food.
The compound is prepared as required, in a standard dosing
volume of 1 mL/kg.
Rats are bled for the zero blood sample and dosed under
C02 sedation. The rats, one at a time, are placed in a primed C02
chamber and taken out as soon as they have lost their righting reflex.
The rat is then placed on a restraining board, a nose cone with C02
delivery is placed over the muzzle and the rat restrained to the board
with elastics. With the use of forceps and scissors, the jugular vein is
exposed and the zero sample taken, followed by a measured dose of
compound which is injected into the jugular vein. Light digital pressure
is applied to the injection site, and the nose cone is removed. The time
is noted. This constitutes the zero time point.
The 5 min bleed is taken by nicking a piece (1-2 mm) off
the tip of the tail. The tail is then stroked with a firm but gentle motion
from the top of the tail to the bottom to milk the blood out of the tail.
Approximately 1 mL of blood is collected into a heparinized collection
vial. Subsequent bleeds are taken in the same fashion, except that there is
no need to nick the tail again. The tail is cleaned with a piece of gauze
and bled, as described above, into the appropriate labelled tubes.
Typical time points for determination of rat blood levels
after LV. dosing are either:
0, 5 min, l5min, 30rnin, 1h, 2h, 6h
o r 0, 5 min, 30min, 1 h, 2h, 4h, 6h.
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Vehicles:
The following vehicles may be used in IV rat blood level
determinations:
Dextrose: 1mL/kg
Moleculosol 25%: 1mL/kg
DMSO (dirnethylsulfoxide): Restricted to a dose volume of 0.1 mL per
animal
PEG 200: Not more than 60% mixed with 40% sterile
water - 1 mL/kg
With Dextrose, either sodium bicarbonate or sodium
carbonate can be added if the solution is cloudy.
For analysis, aliquots are diluted with an equal volume of
acetonitrile and centrifuged to remove protein precipitate. The
supernatant is injected directly onto a C-18 HPLC column with UV
detection. Quantitation is done relative to a clean blood sample spiked
with a known quantity of drug. Bioavailability (F) is assessed by
comparing area under the curve (AUC) i.v. versus p.o.
F - A o x SEiv x 100%
AUCiv DOSEpo
Clearance rates are calculated from the following relation:
CL = DOSEiv(mg(~~1,
AUCiv
The units of CL are mL/h~kg (milliliters per hour kilogram)
Representative Biological Data
Compounds of the present invention are inhibitors of COX-
2 and are thereby useful in the treatment of COX-2 mediated diseases as
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enumerated above. The activities of the compounds against
cyclooxygenase may be seen in the representative results shown below.
In the assay, inhibition is determined by measuring the amount of
prostaglandin E2 (PGE2) synthesized in the presence of AA, COX-1 or
COX-2 and a putative inhibitor. The IC50 values represent the
concentration of putative inhibitor required to lower PGE2 synthesis to
50% of that obtained as compared to the uninhibited control.
Data from three of these biological assays is given for
representative compounds in Table II, along with comparative data for
the following three compounds from U.S. Patent No. 5,474,995:
Me S02Me
A B C
Ex. 7, Col 24, Line 60 Col. 41, Line 5 Ex. 50, Col. 32, Line 5
Table II
Example Cox-2 Whole Cox-1 Selectivity Rat Paw Edema
Blood U937 Ratio (EDSO, mg/kg)
(ICso~ I~M) (ICso~
pM)
A 0.09 0.45 5 3.0
B 0.19 1.9 10 10
C 0.59 0.6 1
1 0.58 30 52 I.7
2 0.89 >100 >112
10 0.46 36 78 2.5
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As can be seen from this data, the compounds of the present
invention show greater COX-2 selectivity and/or potency than A, B, and
C. The basicity of the pyridine ring in these examples also permits the
formation of acid salts, resulting in increased water solubility and give
the potential for parenteral administration in aqueous vehicles.
The invention will now be illustrated by the following non-
limiting examples in which, unless stated otherwise:
(i) all operations were carried out at room or ambient
temperature, that is, at a temperature in the range 18-25°C,
(ii) evaporation of solvent was carried out using a rotary
evaporator under reduced pressure (600-4000 pascals: 4.5
30 mm. Hg) with a bath temperature of up to 60°C,
(iii) the course of reactions was followed by thin layer
chromatography (TLC) and reaction times are given for
illustration only;
(iv) melting points are uncorrected and 'd' indicates
decomposition; the melting points given are those obtained
for the materials prepared as described; polymorphism may
result in isolation of materials with different melting points
in some preparations;
(v) the structure and purity of all final products were
assured by at least one of the following techniques: TLC,
mass spectrometry, nuclear magnetic resonance (NMR}
spectrometry or microanalytical data;
(vi) yields are given for illustration only;
(vii) when given, NMR data is in the form of delta {d)
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values for major diagnostic protons, given in parts per
million (ppm) relative to tetramethylsilane (TMS) as
internal standard, determined at 300 MHz or 400 MHz
using the indicated solvent; conventional abbreviations used
for signal shape are: s. singlet; d. doublet; t. triplet; m.
multiplet; br. broad; etc.: in addition "Ar" signifies an
aromatic signal;
(viii) chemical symbols have their usual meanings; the
following abbreviations have also been used v (volume), w
(weight), b.p. (boiling point), m.p. (melting point), L
(litre(s)), mL (millilitres), g (gram(s)), mg (milligrams(s)),
mol (moles), mmol (millimoles), eq (equivalent{s)), r.t.
(room temperature).
EXAMPLE 1
3-(4-(Methylsulfonyl)phenyl)-2-(3-pyridinyl)-2-cyclopenten-1-one
Step 1: 2-Bromo-2-cvclopenten-1-one
To a 0°C solution of 2-cyclopenten-1-one (125 g, 1.52 mol)
in CC14 { 1.2 L) in a three-neck flask equipped with an overhead stirrer
was added a solution of bromine (269 g, 1.68 mol) in CCI4 (400 mL)
dropwise over 4 h, maintaining an internal temperature <2°C. A
solution of Et3N (310 mL, 2.22 mol) in CC14 (200 mL) was then added
dropwise over 1.5 h, maintaining an internal temperature <10°C. The
resulting suspension was warmed to r.t. for 1 h, then cooled to 0°C and
filtered. The filtrate was washed with two 700 mL portions of 3M HCl
and 500 mL of brine, then filtered through cotton. Concentration
provided 228 g of an orange oil which was crystalized from 150 mL of
2:1 hexane: ether to provide 191 g of the title compound.
1H NMR (CD3COCD3) S 7.94 (1H, t), 2.72 (2H, m), 2.46 {2H, m).
Step 2: 2-Bromo-3-(4-(meth lthio)phen ~~cxclo~enten-1-on_e
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To a -78°C solution of 4-bromothioanisole (35.1 g, 173
mmol) in THF (500 mL) was added nBuLi (1.6 M in hexanes, 107.5
mL, 172 mmol). The solution was stirred for 45 min, then a solution of
2-bromo-2-cyclopenten-1-one (25.4 g, 158 mmol) in THF (150 mL)
was added and the mixture was allowed to warm to 0°C and was
quenched with saturated aqueous NH4Cl. The majority of the solvent
was removed in vacuo and the residue was suspended in water and
extracted with two portions of EtOAc. The organic layers were washed
with brine, dried over MgS04, filtered and concentrated. This material
was dissolved in DMF (300 mL), cooled to 0°C and treated with PDC
(72.4 g, 192 mmol). The resulting mixture was warmed to r.t. and
stirred for 2 h, then poured into H20 ( 1.2 L) and extracted with two
500 mL portions of EtOAc. The organic layers were washed with
brine, dried over MgS04, filtered and concentrated to give the title
compound as a light brown solid which was used directly in the next
step.
Step 3: 2-Bromo-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-1-
Qne
To a 0°C solution of 2-bromo-3-(4-(thiomethyl)phenyl)-2-
cyclopenten-1-one in 2:1 CH2C12/MeOH (500 mL) was added MMPP
{100 g). The mixture was stirred at r.t. overnight, then concentrated
and partitioned between saturated NaHC03, 1M Na2S2O3 and CH2Cl2.
The aqueous layer was extracted with CH2C12, and the combined
organics were washed with brine, filtered through cotton and
evaporated. The resulting solid was swished in CH2Cl~Et20 to provide
23 g of the title compound.
1H NMR (CD3COCD3) S 8.12 (4H, m), 3.22 (2H, m), 3.20 (3H, s), 2.69
(2H, m).
Step 4: Lithium ,3 ~v~.ridinvltrimethvl boronate
To a -88°C solution of 3-bromopyridine (10.1 mL, 104.8
mmol) in Et20 (450 mL) was added a 1.6 M hexane solution of n-BuLi
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(66 mL, 105.6 mmol). The reaction mixture was warmed to -78°C for
1 h to give a thick yellow slurry. Triisopropyl borate (26 mL, 112.7
mmol) was then added to give a slight exotherm (-78°C to -63°C)
and a
clear solution. The mixture was stirred at -78°C for 15 min, then
warmed to r.t. and concentrated to dryness. The residue was dissolved
in MeOH and concentrated three times to give 27.2 g of pyridin-3-yl-
trimethyl lithium boronate. This material was used in the next step
without further purification.
1 H NMR (CD30D, 400 MHz) 8 7.15 ( 1 H, m), 7.85 ( 1 H, m), 8.15 ( 1 H,
m), 8.50 ( 1 H, m)
Step 5: 3-(4-(Methylsulfonyl)phenyl)-2-(3-pyridinyl)-2-
cvclonenten-1-one
To a mixture of 2-bromo-3-(4-(methylsulfonyl)phenyl)-2-
cyclopenten-1-one (3.37 g, 10.7 mmol), lithium 3-pyridinyltrimethyl
boronate (3.43 g, 18.2 mmol), Pd2(dba)3 (0.196 g, 0.214 mmol), and
PPh3 (0.224 g, 0.855 mmol) was added toluene (75 mL), n-propanol
(25 mL), and H20 (25 mL). The mixture was degassed and stirred
under N2 for 15 min then heated to reflux. After 4 h, the reaction
mixture was cooled to r.t., diluted with 100 mL of CH2Cl2 and washed
with H20. The aqueous layer was separated and washed 3 times with
100 mL of CH2Cl2. The organic layers were combined, washed with
brine and filtered through cotton. The filtrate was concentrated to
dryness and the residue was purified by flash chromatography (100 %
EtOAc) followed by swishing in a mixture of CH2Cl2 and Et20 to
provide 2.6 g of the title compound.
1 H NMR (CDC13 ) 8 8.55 ( 1 H, m), 8.34 ( 1 H, m), 7.40 (2H, m), 7.65
( 1 H, m), 7.49 (2H, m), 7.33 ( 1 H, m), 3.12 (2H, m), 3.05 (3H, s), 2.80
(2H, m).
Step 6: 3-(4-(Methylsulfonyl)phenyl)-2-(3-pyridinyl)-2-
cvclonenten-1-one hydrochloride
To a solution of 3-(4-(methylsulfonyl)phenyl)-2-(3-
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pyridinyl)-2-cyclopenten-1-one (5.0 g, 15.96 mmol) in CH2Cl2 (50 mL)
was passed a stream of HCl gas for 10 min. Excess HCl was removed
by bubbling a stream of air through the solution. The solution was then
concentrated and swished in Et20 to give 5.7 g of the title compound.
1H NMR (CDC13) 8 8.70 (1H, m), 8.52 (1H, m), 8.38 (1H, m), 8.00
(2H, m), 7.94 (1H, m), 7.50 (2H, m), 3.20 (2H, m), 3.13 (3H, s), 2.85
(2H, m).
Step 7: 3-(4-(Methylsulfonyl)phenyl)-2-(3-pyridinyl)-2-
c~lopenten-1-one hydromethanesulfonate
To a solution of 3-(4-(methylsulfonyl)phenyl)-2-(3-
pyridinyl)-2-cyclopenten-1-one (I04 mg, 0.33 mmol) in CH2C12 (50
mL) was added methanesulfonic acid (0.02 mL, 0.32 mmol) and the
solution was concentrated to give a foam. The foam was swished in
Et20 to give 108 mg of the title compound as an off white solid.
EXAMPLE 2
2-(5-Chloropyridin-3-yl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
Step 1: Trifluoromethanesulfonic acid 5-chloro-3-pyridin f ester
To a -78°C solution of 5-chloro-3-hyroxypyridine (1.0 g,
7.72 mmol) and diisopropylethyl amine (1.88 mL, I0.81 mmol) in
CH2Cl2 (35 mL) was added trifluoromethanesulfonic anhydride (1.55
mL, 9.26 mmol) slowly to give a dark red solution. After 1 mL of
trifluoromethanesulfonic anhydride was added, a precipitate formed and
the mixture became hard to stir. The mixture was immersed in a -10°C
bath and the rest of the trifluoromethanesulfonic anhydride was added.
After 1 S min, the mixture was washed with H20 and brine, filtered
through cotton and concentrated to dryness. The residue was purified
by flash chromatography ( 10 % EtOAc/ hexanes) to give 510 mg of the
title compound.
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1H NMR (CD3COCD3) 8 8.75 (2H, m), 8.20 (1H, m).
Step 2: 3-Trimethvlstannanvl-5-chlorop, n
To a mixture of Pd2(dba)3 (0.038 g, 0.04 mmol) and PPh3
(0.086 g, 0.33 mmol) was added dioxane (2 mL). The resulting
suspension was degassed and stirred at r.t. for fifteen minutes before it
was transferred via cannula into a degassed r.t. mixture of
trifluoromethanesulfonic acid 5-chloro-3-pyridinyi ester (0.510 g, 2.06
mmol), hexamethylditin (0.443 mL, 2.16 mmol), LiCI (0.262 g, 6.18
mmol), and a few crystals of BHT. The resulting mixture was heated to
reflux for 2.5 h, then cooled to r.t., diluted with EtOAc, washed with
10% NH40H and brine, dried over MgS04, filtered, and concentrated to
dryness. The residue was used in step 3 without further purification.
Step 3: 2-(5-Chloro-3-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
c,~penten-1-one
To a degassed r.t. solution of 2-bromo-3-(4-
(methylsulfonyl)phenyl)-2-cyclopenten-1-one (0.630 g, 2.0 mmol),
Pd2(dba)3 (0.037 g, 0.04 mmol), and AsPh3 (0.098 g, 0.32 mmol) in 5
mL NMP was added a degassed NMP solution (5 mL) of 3-
trimethylstannanyl-S-chloropyridine (--2.0 mmol). The resulting
mixture was heated to 60°C for 16 h. The mixture was then cooled to
r.t., diluted with EtOAc, washed with water and brine, dried over
MgS04, and concentrated to dryness. The residue was purified by flash
chromatography (80 % EtOAc/ hexanes) followed by a CH2Cl2./Et20
swish to provide 0.215 g of the title compound.
1H NMR (CD3COCD3) 8 8.50 (1H, d), 8.20 (1H, d), 7.95 (2H, m),
7.22, (1H, dd), 7.18 (2H, m), 3.22 (2H, m), 3.16 (3H, s), 2.71 (2H, m).
EXAMPLE 3
2-(5-Bromo-3-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
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Step 1: Lithium 5-bromo-3-pyridinvltrimethyl boronate
To a -105°C solution of 3,5-dibromopyridine (2.00 mL,
8.44 mmol) in Et20 (40 mL) was added a 1.6 M solution of n-BuLi
(5.54 mL, 8.86 mmol). The reaction mixture was allowed to stir at
-105°C for five minutes to give a yellow precipitate. Triisopropyl
borate (3.90 mL, 16.88 mmol) was then added and the reaction mixture
was allowed to warm to r.t. The residue was diluted with MeOH and
concentrated three times to give a white solid which was used in the next
step without further purification.
Step 2: 2-(3-Pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
c~clopenten-1-one
To a mixture of 2-bromo-3-(4-(methylsulfonyl)phenyl)-2-
cyclopenten-1-one (0.500 g, 1.59 mmol), lithium 5-bromo-3-
pyridinyltrimethyl boronate (0.729 g, 3.17 mmol), Pd2(dba)3 (0.044 g,
0.048 mmol), and PPh3 (0.050 g, 0.190 mmol) was added toluene ( 15
mL), n-propanol (5 mL), and H20 (5 mL). The mixture was degassed
and stirred under N2 for 15 min before diethyl amine (0.427 mL, 4.12
mmol) was added and the mixture was heated to reflux. After three
hours, the reaction mixture was cooled to r.t., diluted with CH2C12 and
washed with H20. The H20 was separated and washed 3 times with
CH2C12. The organic layers were combined, washed with brine and
filtered through cotton. The filtrate was concentrated to dryness and the
residue was purified by flash chromatography (75% ETOAc/ hexanes)
followed by a CH2C12/Et20 swish, to yield 0.160 g of the title
compound.
1H NMR (CD3COCD3) S 8.60 (1H, d), 8.25 (1H, d), 7.96 (2H, m), 7.37
(1H, dd), 7.69 (2H, m), 3.22 (2H, m), 3.14 (3H, s), 2.73 (2H, m).
EXAMPLE 4
2-(2-Methyl-S-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
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Step 1: Trifluoromethanesulfonic acid 2-methyl-5-pyridin 1v ester
To a -78°C solution of 2-methyl-5-hydroxypyridine (1.0 g,
9.16 mmol) and diisopropylethyl amine (2.23 mL, 12.83 mmol} in
CH2C12 (50 mL) was added trifluoromethanesulfonic anhydride ( 1.85
mL, 11.0 mmol). The reaction mixture was then allowed to warm to
r.t. After 30 min, the mixture was washed with water and brine,
filtered through cotton and concentrated to dryness. The residue was
purified by flash chromatography (12.5 % EtOAc/hexanes) to give
0.483 g of the title compound.
1H NMR (CD3COCD3) 8 8.57 (1H, d), 7.80 (1H, dd), 7.47 (1H, d),
2.55 (3H, s).
Step 2: 5-Trimethvlstannanvl-2-meth, ly,~. yridine
To a mixture of Pd2(dba)3 (0.047 g, 0.04 mmol), and PPh3
(0.085 g, 0.32 mmol) was added dioxane (2 mL). The resulting
suspension was degassed and stirred at r.t. for 15 min before it was
transferred via cannula into a degassed r.t. dioxane suspension (8 mL)
of trifluoromethanesulfonic acid 2-methyl-5-pyridinyl ester (0.460 g,
2.02 mmol), hexamethylditin (0.435 mL, 2.13 mmol}, LiCI (0.257 g,
6.07 mmol), and a few crystals of BHT. The resulting mixture was
heated to reflux for 2.5 h before it was cooled to r.t., diluted with
CH2C12, washed with 10 % NH40H and brine, filtered through cotton,
and concentrated to dryness. The residue was used in step 3 without
further purification.
Step 3: 2-(2-Methyl-5-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
cvclonenten-1-one
To a degassed r.t. solution of 2-bromo-3-(4-
(methylsulfonyl)-phenyl)-2-cyclopenten-1-one (0.315 g, 1.0 mmol),
Pd2(dba)3 (0.018 g, 0.02 mmol), and AsPh3 (0.049 g, 0.16 mmol) in
NMP (2.5 mL) was added a degassed NMP solution (2.5 mL) of 5-
trimethylstannanyl-2-methylpyridine (~2.0 mmol). The resulting
mixture was heated to 60°C for 16 hours, then to 100°C for a
further
3.5 h. The mixture was then cooled to r.t., diluted with EtOAc, washed
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2 times with 10% NH40H and brine, dried over MgS04, and
concentrated to dryness. The residue was purified by flash
chromatography ( 100 % EtOAc/ hexanes) to provide 0.070 g of the title
compound as a rigid foam.
1H NMR (CD3COCD3) b 8.20 (1H, d), 7.94 (2H, m), 7.65 (2H, m),
7.47 (1H, dd), 7.20 (1H, d), 3.18 (2H, m), 3.14 (3H, s), 2.69 (2H, m).
EXAMPLE 5
2-(2-Methoxy-5-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
Step 1: 5-Bromo-2-methoxYp n~ dine
To a solution of 2,5-dibromopyridine ( 1.4 g, 5.9 mmol) in
DMF ( l OmL) was added MeOH (4 mL), and 8N aqueous KOH ( 1 mL).
The solution was heated to 100°C for 2 h, then cooled and
partitioned
between Et20 and H20. The organic layer was washed with brine,
dried over MgS04 and concentrated to provide 840 mg of the title
compound, which was used in the next step without further purification.
Step 2: Lithium 2-methox~p ridinyltrimethyl boronate
To a -78°C solution of the total sample of 5-bromo-2-
methoxypyridine from Step 1 in Et20 (20 mL) was added a 1.6 M
solution of n-BuLi (3.5 mL, 5.6 mmol). The reaction mixture was
allowed to stir IO min to give an orange suspension. Triisopropyi
borate ( 1.5 mL, 6.5 mmol) was then added and the reaction mixture was
allowed to warm to r.t. The residue was diluted with MeOH and
concentrated three times to give a white solid which was used in the next
step without further purification.
Step 3: 2-(2-Methoxy-S-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
c~clonenten-1-one
A mixture of the total sample of lithium 2-methoxy-5-
pyridinyltrimethyl boronate from Step 2, 2-bromo-3-(4-
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(methylsulfonyl)phenyl)-2-cyclopenten-1-one (400 mg, 1.3 mmol),
Pd2(dba)3 (70 mg, 0.08 mmol) and PPh3 (83 mg, 0.32 mmol) was
dissolved in 3:1:1 toluene: n-propanol: H20 {50 mL) and degassed. The
solution was stirred 10 min at r.t., heated to reflux for 2.5 h, then
cooled and concentrated in vacuo. The residue was partitioned between
CH2Cl2 and aqueous NaHC03. The organic phase was washed with
brine, filtered through cotton and concentrated. Purification by flash
chromatography (60% EtOAc/hexanes) provided 317 mg of an oil
which was crystalized from EtOAc/hexanes to give 230 mg of the title
compound.
1H NMR (CD3COCD3, 300 MHz) 8 7.95 (3H, m); 7.68 (2H, m); 7.48
(/H, dd); 6.72 (1H, dd), 3.87 (3H, s), 3.14 (2H, m), 3.12 {3H, s), 2.68
(2H, m).
EXAMPLE 9
2-(2-Pvridinyl)-3-(4-(methylsulfonvl)phen~r~)-2-,~ clopenten-1-one
Step 1: Trifluoromethanesulfonic acid 2-nvridinvl ester
To a -78°C solution of 2-hydroxypyridine (1.0 g, 10.5
mmol) and diisopropylethyl amine (2.56 mL, 14.7 mmol) in CH2Cl2
(40 mL) was added trifluoromethanesulfonic anhydride (2.12 mL, 12.6
mmol). The reaction mixture was then allowed to warm to r.t.. After
25 min, the mixture was washed with H20 and brine, filtered through
cotton and concentrated to dryness. The residue was purified by flash
chromatography (9 % EtOAcltlexanes) to give 1.60 g of the title
compound.
IH NMR (CD3COCD3) 8 8.46 (1H, m), 8.18 (1H, m), 7.62 (1H, m),
7.49 ( 1 H, d).
Step 2: 2-Trimethylstannanvl P ridine
To a mixture of Pd2(dba)3 (0.129 g, 0.14 mmol), and PPh3
(0.296 g, 1.13 mmol) was added dioxane (6 mL). The resulting
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suspension was degassed and stirred at r.t. for 15 min before it was
transferred via cannula into a degassed r.t. suspension of
trifluoromethanesulfonic acid 2-pyridinyl ester ( 1.6 g, 7.04 mmol),
hexamethylditin ( 1.51 mL, 7.40 mmol), LiCI (0.895 g, 21.1 mmol), and
a few crystals of BHT in dioxane (23 mL). The resulting mixture was
heated to reflux for 3 h before it was cooled to room temperature,
diluted with CH2C12, washed with 10% NH40H and brine, filtered
through cotton, and concentrated to dryness. The residue was used in
step 3 without further purification.
Step 3: 2-(2-Pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
cyclopenten-1-one
To a degassed r.t. solution of 2-bromo-3-(4-
(methylsulfonyl)phenyl)-2-cyclopenten-1-one (1.103 g, 3.5 mmol),
i 5 Pd2(dba)3 (0.064 g, 0.07 mmol), and AsPh3 (0.171 g, 0.56 mmol) in
NMP (7.5 mL) was added a degassed NMP solution (10 mL) of 2-
trimethylstannanyl pyridine (--7.0 mmol). The resulting mixture was
heated to 100°C for 16 hours. The mixture was then cooled to r.t.,
diluted with EtOAc, washed 3 times with 10% NH40H and brine, dried
over MgS04, and concentrated to dryness. The residue was purified by
flash chromatography (5% MeOH/ EtOAc) to provide 0.215 g of the
title compound.
1H NMR (CD3COCD3) 8 8.46 (1H, m), 7.88 (2H, m), 7.80 (1H, m),
7.62 (2H, m), 7.45 ( 1 H, m), 7.30 ( 1 H, m), 3.21 (2H, m), 3.12 (2H, m),
2.71 (2H, m).
EXAMPLE 10
2-(5-Chloro-2-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
Step 1: Trifluoromethanesulfonic acid 5-chloro-2-pyridinyl ester
To a -78°C solution of 5-chloro-2-hydroxypyridine (1.0 g,
7.72 mmol) and diisopropylethyl amine (1.88 mL, 10.81 mmol) in
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CH2C12 (35 mL) was added trifluoromethanesulfonic anhydride ( 1.56
mL, 9.26 mmol), and the reaction mixture was allowed to warm to r.t.
After 30 min, the mixture was washed with H20 and brine, filtered
through cotton and concentrated to dryness. The residue was purified
S by flash chromatography (8 % EtOAc/hexanes) and to give 1.0 g of the
title compound.
1H NMR (CD3COCD3) 8 8.50 (1H, d), 8.23 (1H, dd), 7.58 (1H, d).
Step 2: 2-Trimethylstannanvl-5-chlorop, ridine
To a degassed room temperature mixture of
trifluoromethanesulfonic acid 5-chloro-3-pyridinyl ester (0.510 g, 2.06
mmol), hexamethylditin (0.443 mL, 2.16 mmol), LiCI (0.262 g, 6.18
mmol), and a few crystals of BHT were added a freshly prepared
solution of 0.1 M solution of Pd(PPh3)4 in toluene (0.807 mL, 0.081
mmol). The resulting mixture was heated to reflux for 1.5 h before it
was cooled to r.t., diluted with EtOAc, washed with 10 % NH40H and
brine, dried over MgS04, filtered, and concentrated to dryness. The
residue was used in step 3 without further purification.
Step 3: 2-(5-Chloro-2-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-
cvclopenten-1-one
To a degassed r.t. solution of 2-bromo-3-(4-
(methylsulfonyi)-phenyl)-2-cyclopenten-1-one (0.630 g, 2.0 mmol),
Pd2(dba)3 (0.036 g, 0.04 mmol), and AsPh3 (0.098 g, 0.32 mmol) in
NMP (5 mL) was added a degassed NMP solution (8 mL) of 2-
trimethylstannanyl-5-chloropyridine (~4.0 mmol). The resulting
mixture was heated to 60°C for 16 h, then to 100°C for a further
2 h.
The mixture was then cooled to r.t., diluted with EtOAc, washed 2 times
with 10% NH40H and brine, dried over MgS04, and concentrated to
dryness. The residue was purified by flash chromatography (70%
EtOAc/hexanes) followed by a CH2Cl2/ Et20 swish to provide 130 mg
of the title compound.
1H NMR (CD3SOCD3) 8 8.54 (1H, d), 8.00 (1H, dd), 7.39 (2H, m),
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7.55 (2H, m), 7.45 (1H, d), 3.23 (3H, s), 3.13 (2H, m), 2.69 (2H, m).
EXAMPLE 12
2-(5-Bromo-2-pyridinyl)-3-(4-(methylsulfonyl)phenyl)-2-cyclopenten-
1-one
Step 1: 2-Trimethylstannan~l-5-bromop,~d_ine
A mixture of 2,5-dibromopyridine ( 1.42 g, 6.0 mmol),
Pd2(dba)3 (178 mg, 0.19 mmol) and PPh3 (315 mg, 1.20 mmol) was
dissolved in dioxane ( 15 mL) and degassed. After 10 min at r.t.,
hexamethylditin ( 1.4 mL, 6.8 mmol) was added and the mixture was
heated to reflux for 1.5 h, then cooled to r.t. The mixture was
partitioned between saturated aqueous NaHC03 and CH2C12. The
organic phase was washed with brine, filtered through cotton and
concentrated. The residue was used directly in step 2 without further
purification.
Step 2: 2-{5-Bromo-2-pyridinyl}-3-(4-(methylsulfonyl)phenyl}-2-
,c~rclopenten-1-one
A mixture of 2-bromo-3-(4-(methylsulfonyl)-phenyl}-2-
cyclopenten-1-one (700 mg, 2.2 mmol), Pd2(dba)3 (170 mg, 0.18
mmol), and the total sample of 2-trimethylstannanyl-5-bromopyridine
from Step 1 was dissolved in NMP (10 mL) and degassed. The resulting
solution was heated to 100°C for 3.5 h then cooled. The mixture was
diluted with EtOAc, washed 2 times with 10% NH40H and brine, dried
over MgS04, and concentrated. The residue was purified by flash
chromatography (70 % EtOAc/hexanes) followed by an EtOAc/ Et20
swish to provide 110 mg of the title compound.
1H NMR (CDC13, 300 MHz) 8 8.59 (1H, d), 7.90 (3H, m), 7.48 (2H,
m), 7.40 (1H, d), 3.12 (2H, m), 3.06 (3H, s), 2.80 (2H, m).
EXAMPLE 16
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2-(4-Pvridinyll-3-(4-(methylsulfonyl,phenyl)-2-cyclopenten-1-one
Step 1: Lithium 4-p, ridinvltrimethvl boronate
To a -107°C solution of 4-bromopyridine (1.77 g, 11.20
mmol) in Et20 (50 mL) was added a 1.6 M solution of n-BuLi(5.54
mL, 8.86 mmol). The reaction mixture was allowed to'stir at -105°C
for flue minutes. Triisopropyl borate (3.62 mL, 15.68 mmol) was then
added and the reaction mixture was then allowed to warm to r.t. The
reaction mixture was diluted with MeOH and concentrated three times to
give a white solid which was used in the next step without further
purification.
1H NMR (CD30D, 400 MHz) 8 8.19 (2H, m), 7.47 (2H, m)
Step 2: 2-(4-Pyridinyl)-3-(4-(methylsulfonyl)phenyl}-2-
c~penten-1-one
To a mixture of 2-bromo-3-{4-(methylsulfonyl)phenyl)-2-
cyclopenten-1-one (0.500 g, 1.59 mmol), lithium 4-pyridinyltrimethyl
boronate (0.480 g, 2.54 mmol), Pd2(dba)3 (0.029 g, 0.03 mmol), and
PPh3 (0.033 g, 0.13 mmol) was added toluene ( 15 mL), n-propanol (5
mL), and H20 (5 mL). The mixture was degassed and stirred under N2
for 15 min before it was heated to reflux. After 3.5 h, the reaction
mixture was cooled to r.t., diluted with CH2Cl2, washed with H20 and
brine, and filtered through cotton. The filtrate was concentrated to
dryness and the residue was purified by flash chromatography (S %
MeOH/EtOAc) followed by a CH2C121Et20 swish, to yield 0.130 g of
the title product.
1H NMR (CD3COCD3) 8 8.53 (2H, m), 7.95 (2H, m), 7.63 (2H, m),
7.15 (2H, m), 3.20 (2H, m), 3.14 (3H, s), 2.71 (2H, m).
