2-aminopyridines as inhibitors of cyclooxygenase-2

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 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 labor, 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 cyclooxygenase-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 Drug News and Perspectives, Vol. 7, pp. 501-512, 1994.
3. David B. Reitz and Karen Seibert, "Selective Cyclooxygenase Inhibitors" in Annual Reports in Medicinal Chemistry, James A. Bristol, Editor, Vol. 30, pp. 179-188, 1995.
4. Don E. Griswold and Jerry L. Adams, "Constitutive Cyclooxygenase (COX-1) and Inducible Cyclooxygenase (COX-2): Rationale for Selective Inhibition and Progress to Date" in Medicinal Research Reviews, Vol. 16, pp. 181-206, 1996.
SUMMARY OF THE INVENTION
The invention encompasses the novel compound of Formula as well as a method of treating cyclooxygenase-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. ##STR2##
The invention also encompasses certain pharmaceutical compositions for treatment of cyclooxygenase-2 mediated diseases comprising 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 cyclooxygenase-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, ##STR3## --AR is selected from the group consisting of ##STR4## or a pharmaceutically acceptable salt thereof wherein: X is selected from the group consisting of
(a) CR.sup.3 R.sup.4,
(b) O,
(c) S,
R.sup.1 is selected from the group consisting of
(a) CH.sub.3,
(b) NH.sub.2,
(c) NHC(O)CF.sub.3,
R.sup.2 is chosen from the group consisting of
(a) hydrogen
(b) C.sub.1-6 alkyl
(c) C.sub.1-6 alkoxy,
(d) C.sub.1-6 alkylthio,
(e) C.sub.1-6 fluoroalkyl,
(f) C.sub.1-6 fluoroalkoxy,
(g) CN,
(h) --CO.sub.2 R.sup.6,
(i) --C(R.sup.7)(R.sup.8)--OH,
(j) --C.sub.1-6 alkyl-CO.sub.2 --R.sup.9,
(k) halo,
(l) hydroxy,
(m) N.sub.3,
(m) NO.sub.2,
(n) NR.sup.10 R.sup.11,
(o) NHCOR.sup.12,
R.sup.3 and R.sup.4 are independently chosen from the group consisting of
(a) hydrogen,
(b) C.sub.1-6 alkyl,
(c) (CH.sub.2).sub.p OR.sup.5,
(d) F,
or R.sup.3 and R.sup.4 are together O,
R.sup.5 is selected from the group consisting of
(a) hydrogen,
(b) C.sub.1-6 alkyl,
(c) C.sub.1-5 acyl,
R.sup.6 to R.sup.12 are independently chosen from the group consisting of
(a) hydrogen
(b) C.sub.1-6 alkyl, and
p is 0, 1, 2.
One preferred embodiment of the invention is that wherein R.sup.1 is CH.sub.3.
Another preferred embodiment of the invention is that wherein R.sup.2 is halo or C.sub.1-6 fluoroalkyl.
Another preferred embodiment of the invention is that wherein X is CR.sup.3 R.sup.4.
In another aspect, the invention also encompasses a pharmaceutical composition for treating an inflammatory disease susceptible to treatment with an non-steroidal anti-inflammatory agent comprising:
a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier.
In another aspect the invention also encompasses a pharmaceutical composition for treating cyclooxygenase mediated diseases advantageously treated by an active agent that selectively inhibits COX-2 in preference to COX-1 comprising:
a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier.
In another aspect the invention also encompasses a method of treating an inflammatory disease susceptible to treatment with an non-steroidal anti-inflammatory agent comprising:
administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier.
In another aspect the invention also encompasses a method of treating cyclooxygenase mediated diseases advantageously treated by an active agent that selectively inhibits COX-2 in preference to COX-1 comprising:
administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of formula I.
In another aspect the invention also encompasses the use of a compound of formula I or a pharmaceutical composition in the manufacture of a medicament for the treatment of an inflammatory disease susceptible to treatment with an a non-steroidal antiinflammatory agent.
The invention is illustrated by the compounds of the Examples disclosed herein as well as the compounds of Table I.
______________________________________1 Definitions The following abbreviations have the indicated meanings______________________________________AA = arachidonic acid Ac = acetyl AIBN = 2.2--azobisisobutyronitrile Bn = benzyl CHO = chinese hamster ovary CMC = 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimidemetho-p-toluenesulfonate COX = cyclooxygenase DBU = diazabicyclo[5.4.0]undec-7-ene DMAP = 4-(dimethylamino)pyridine DMF = N,N-dimethylformamide DMSO = dimethyl sulfoxide Et.sub.3 N triethylamine HBSS = Hanks balanced salt solution HEPES = N-[2-Hydroxyethyl]piperazine-N.sup.1 -[2- ethanesulfonic acid] HWB = human whole blood IPA = isopropyl alcohol KHMDS = potassium hexamethyldisilazane LDA = lithium diisopropylamide LPS = lipopolysaccharide mCPBA = metachloro perbenzoic acid MMPP = magnesium monoperoxyphthalate Ms = methanesulfonyl = mesyl MsO = methanesulfonate = mesylate NBS = N-bromosuccinimide NCS = N-chlorosuccinimide NIS = N-idosuccinimide NSAID = non-steroidal anti-inflammatory drug ODCB = o-dichlorobenzene Oxone .RTM. = potassium peroxymonosulfate PCC = pyridinium chlorochromate PDC = pyridinium dichromate r.t. = room temperature rac. = racemic Tf = trifluoromethanesulfonyl = triflyl TFAA = trifluoroacetic anhydride TfO = trifluromethanesulfonate = triflate THF = tetrahydrofuran TLC = thin layer chromatography TMPD = N,N,N',N'-tetramethyl-p-phenylenediamine Ts = p-toluenesulfonyl = tosyl TsO = p-toluenesulfonate = tosylate Tz = 1H (or 2H)-tetrazol-5-yl SO.sub.2 Me = methyl sulfone (also SO.sub.2 CH.sub.3) SO.sub.2 NH.sub.2 = sulfonamide______________________________________
______________________________________Alkyl group abbreviations Dose Abbreviations______________________________________Me = methyl bid = bis in die = twice daily Et = ethyl qid = quater in die = four times a day n-Pr = normal propyl tid = ter in die = three times a day 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______________________________________
For purposes of this specification "Alkyl" means linear branched and cyclic structures, and combinations thereof, containing the indicated number of carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, s- and t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, eicosyl, 3,7-diethyl-2,2-dimethyl-4-propylnonyl, cyclopropyl, cyclopentyl, cycloheptyl, adamantyl, cyclododecylmethyl, 2-ethyl-1-bicyclo[4.4.0]decyl and the like.
For purposes of this specification "Fluoro alkyl" means alkyl groups, containing the indicated number of carbon atoms, in which one or more hydrogens is replaced by fluorine. Examples are --CF.sub.3, --CH.sub.2 CH.sub.2 F, --CH.sub.2 CF.sub.3, c--Pr--F.sub.5, c--Hex--F.sub.11 and the like.
For purposes of this specification "Alkoxy" means alkoxy groups of the indicated number of carbon atoms of a straight, branched, or cyclic configuration. Examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, cyclohexyloxy, and the like.
For purposes of this specification "Alkylthio" means alkylthio groups of the indicated number of carbon atoms of a straight, branched or cyclic configuration. Examples of alkylthio groups include methylthio, propylthio, isopropylthio, cycloheptylthio, etc. By way of illustration, the propylthio group signifies --SCH.sub.2 CH.sub.2 CH.sub.3.
For purposes of this specification "Fluoroalkoxy" means alkoxy groups of the indicated number of carbon atoms of a straight, branched, or cyclic configuration, in which one or more hydrogens is replaced by fluorine. Examples of fluoroalkoxy alkoxy groups include --OCF.sub.3, --OCHF.sub.2, --OCH.sub.2 CH.sub.2 CH.sub.2 F, and the like.
For purposes of this specification "halo" means F, Cl, Br, or I.
Exemplifying the invention are:
(1) 3-(4-Methylsulfonyl)phenyl-2-pyrrolidin-1-yl-5-trifluoromethylpyridine,
(2) 3-(4-Methylsulfonyl)phenyl-2-piperidin-1-yl-5-trifluoromethylpyridine,
(3) 5-Chloro-3-(4-methylsulfonyl)phenyl-2-piperidin-1-ylpyridine,
(4) 3-(4-Methylsulfonyl)phenyl-2-piperidin-1-ylpyridine,
(5) 3-(4-Methylsulfonyl)phenyl-2-(1,2,3,6-tetrahydropyridinyl)-5-trifluoromethylpyridine,
(6) 2-(Homopiperidin-1-yl)-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine,
(7) 3-(4-Methylsulfonyl)phenyl-2-((2S)-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine,
(8) 3-(4-Methylsulfonyl)phenyl-2-((2R)-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine,
(9) 5-Chloro-3-(4-methylsulfonyl)phenyl-2-((2S)-2-hydroxymethyl)pyrrolidin-1-ylpyridine,
(10) 3-(4-Methylsulfonyl)phenyl-2-((2S)-2-methoxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine,
(11) 3-(4-Methylsulfonyl)phenyl-2-((2S)-2-acetoxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine,
(12) 5-Chloro-3-(4-methylsulfonyl)phenyl-2-((2S)-2-methoxymethyl)pyrrolidin-1-ylpyridine,
(13) 3-(4-Methylsulfonyl)phenyl-2-(2-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine,
(14) (-)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine,
(15) (+)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine,
(16) 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-ylpyridine,
(17) 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl-3-methyl)piperidin-1-yl-5-trifluoromethylpyridine,
(18) 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)homopiperidin-1-yl-5-trifluoromethylpyridine,
(19) 3-(4-Methylsulfonyl)phenyl-2-(2-(2-hydroxyethyl))piperidin-1-yl-5-trifluoromethylpyridine,
(20) 3-(4-Methylsulfonyl)phenyl-2-(4-oxo)piperidin-1-yl-5-trifluoromethylpyridine,
(21) 3-(4-Methylsulfonyl)phenyl-2-(3-oxo)piperidin-1-yl-5-trifluoromethylpyridine,
(22) 3-(4-Methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine,
(23) 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine,
(24) 2-(4,4-Difluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine,
(25) 2-(3,3-Difluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine,
(26) 2-(4-Fluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine,
(27) 3-(4-Methylsulfonyl)phenyl-2-morpholin-4-yl-5-trifluoromethylpyridine,
(28) 3-(4-Methylsulfonyl)phenyl-2-thiomorpholin-4-yl-5-trifluoromethylpyridine,
Some of the compounds described herein contain one or more asymmetric centers 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 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.
In a second embodiment, the invention encompasses pharmaceutical compositions for inhibiting cyclooxygenase and for treating cyclooxygenase mediated diseases as disclosed herein comprising a pharmaceutically acceptable carrier and a non-toxic therapeutically effective amount of compound of formula I as described above.
Within this embodiment the invention encompasses pharmaceutical compositions for inhibiting cyclooxygenase-2 and for treating cyclooxygenase-2 mediated diseases as disclosed herein comprising a pharmaceutically acceptable carrier and a non-toxic therapeutically effective amount of compound of formula I as described above.
In a third 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.
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, such as arginine, betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like, and basic ion exchange resins.
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.
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 tumor growth and hence can be used in the treatment of cancer. Compound I may also be of use in the treatment and/or prevention of cyclooxygenase-mediated proliferative disorders such as may occur in diabetic retinopathy and tumor 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 labor, asthma and eosinophil related disorders. It will also be of use in the treatment of Alzheimer's disease, and for the prevention of bone loss (treatment of osteoporosis) and for the treatment of glaucoma.
By virtue of its high cyclooxygenase-2 (COX-2) activity and/or its specificity for cyclooxygenase-2 over cyclooxygenase-1 (COX-1), Compound I will prove useful as an alternative to conventional non-steroidal antiinflammatory drugs (NSAID'S) particularly where 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 anemia such as hypoprothrombinemia, haemophilia or other bleeding problems; kidney disease; those prior to surgery or taking anticoagulants.
Similarly, Compound 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 cyclooxygenase-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 acetominophen or phenacetin; a potentiator including caffeine; an H.sub.2 -antagonist, aluminum or magnesium hydroxide, simethicone, a decongestant including phenylephrine, phenylpropanolamine, pseudophedrine, oxymetazoline, ephinephrine, naphazoline, xylometazoline, propylhexedrine, or levodesoxyephedrine; 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 ingredients as listed immediately above.
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, intramuscular, 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 cyclooxygenase-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, flavoring agents, coloring 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 starch, or alginic 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. Pat. No. 4,266,108; 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, one or more coloring agents, one or more flavoring agents, and one or more 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 flavoring 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, flavoring and coloring 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, polyoxy-ethylene sorbitan monooleate. The emulsions may also contain sweetening and flavoring 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 flavoring and coloring agents. The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleaginous 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 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. 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 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.
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 administration of humans may contain from 0.5 mg to 6 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.
Methods of Synthesis
The compounds of Formula I of the present invention can be prepared according to the synthetic routes outlined in Scheme 1 and by following the methods described therein.
Scheme 1 The 2-aminopyridines of Formula I may be prepared in a multi-step sequence from the requisite 2-aminopyridine II. Initial bromination of II with bromine in acetic acid provides the bromide III. A palladium-catalyzed coupling of III with 4-(methylthio)phenylboronic acid in the presence of a suitable base, such as sodium carbonate, provides the sulfide IV which can be oxidized using one of several oxidants, such as MMPP, oxone.RTM., or OsO.sub.4 /NMO to the corresponding sulfone V. The amino pyridine V can be converted to the 2-halopyridine VI (X=Br, Cl) by treatment of V with sodium nitrite and either HBr/Br.sub.2 or HCl followed by reaction with POCl.sub.3. Treatment of VI with an appropriately substituted amine VII and a suitable base such as K.sub.2 CO.sub.3, Cs.sub.2 CO.sub.3 or KH in an inert solvent such as DMF or DMSO, or alternatively heating a neat mixture of the amine VII and VI in the presence of a copper salt such as CuI, provides the 2-aminopyridine of Formula I. ##STR5## Representative Compounds
Tables I illustrates novel compounds of the present invention.
TABLE I______________________________________ #STR6## Example R.sup.1 R.sup.2 Ar Stereochemistry______________________________________ 1 Me CF.sub.3 -- R7## - 2 Me CF.sub.3 -- R8## - 3 Me Cl -- R9## - 4 Me H -- R10## - 5 Me CF.sub.3 -- R11## - 6 Me CF.sub.3 -- R12## - 7 Me CF.sub.3 (S) 13## - 8 Me CF.sub.3 (R) 14## - 9 Me Cl (S) 15## - 10 Me CF.sub.3 (S) 16## - 11 Me CF.sub.3 (S) 17## - 12 Me Cl (S) 18## - 13 Me CF.sub.3 racemic - 14 Me CF.sub.3 (-)-(S) - 15 Me CF.sub.3 (+)-(R) - 16 Me Cl racemic - 17 Me CF.sub.3 racemic - 18 Me CF.sub.3 racemic - 19 Me CF.sub.3 racemic - 20 Me CF.sub.3 -- R26## - 21 Me CF.sub.3 -- R27## - 22 Me CF.sub.3 -- R28## - 23 Me CF.sub.3 racemic - 24 Me CF.sub.3 -- R30## - 25 Me CF.sub.3 -- R31## - 26 Me CF.sub.3 -- R32## - 27 Me CF.sub.3 -- R33## - 28 Me CF.sub.3 --TR34##______________________________________
Assays for determining Biological Activity
The compound of Formula I can be tested using the following assays to determine their cyclooxygenase-2 inhibiting activity.
INHIBITION OF CYCLOOXYGENASE ACTIVITY
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.times.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 cell concentration of 1.5.times.10.sup.6 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.times.10.sup.6 cells in 200 .mu.l) are preincubated with 3 .mu.l of the test drug or DMSO vehicle for 15 min at 37.degree. C. Working solutions of peroxide-free AA (5.5 .mu.M and 110 .mu.M 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 HBSS 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 .mu.M AA in the CHO[hCOX-1] assay and a final concentration of 10 .mu.M AA in the CHO[hCOX-2] assay. The reaction is terminated by the addition of 10 .mu.l 1 N HCl followed by neutralization with 20 .mu.l of 0.5 N NaOH. The samples are centrifuged at 300.times.g at 4.degree. C. for 10 min, and an aliquot of the clarified supernatant is appropriately diluted for the determination of PGE.sub.2 levels using an enzyme-linked immunoassay for PGE.sub.2 (Correlate PGE.sub.2 enzyme immunoassay kit, Assay Designs, Inc.). Cyclooxygenase activity in the absence of test compounds is determined as the difference in PGE.sub.2 levels of cells challenged with arachidonic acid versus the PGE.sub.2 levels in cells mock-challenged with ethanol vehicle. Inhibition of PGE.sub.2 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.times.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-HCl, pH 7.4, 10 mM EDTA, 2 .mu.g/ml leupeptin, 2 .mu.g/ml soybean trypsin inhibitor, 2 .mu.g/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.times.g for 10 min at 4.degree. C. The supernatant is centrifuged at 100,000.times.g for 1 hr at 4.degree. C. The 100,000.times.g microsomal pellet is resuspended in 0.1 M Tris-HCl, pH 7.4, 10 mM EDTA to approximately 7 mg protein/ml and stored at -80.degree. C.
Microsomal preparations are thawed immediately prior to use, subjected to a brief sonication, and then diluted to a protein concentration of 125 .mu.g/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 .mu.M hematin. Assays are performed in duplicate in a final volume of 250 .mu.l. Initially, 5 .mu.l of DMSO vehicle or drug in DMSO are added to 20 .mu.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 .mu.l of the microsomal preparation are then added and pre-incubated for 15 min at room temperature before addition of 25 .mu.l of 1 M arachidonic acid in 0.1 M Tris-HCl 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 .mu.l of 1 N HCl. Samples are neutralized with 25 .mu.l of 1 N NaOH prior to quantitation of PGE.sub.2 content by radioimmunoassay (Dupont-NEN or Amersham assay kits). Cyclooxygenase activity is defined as the difference between PGE.sub.2 levels in samples incubated in the presence of arachidonic acid and ethanol vehicle.
Assay of the activity of 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 PGG.sub.2 to PGH.sub.2 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, 111-118). The assay mixture (180 .mu.L) contains 100 mM sodium phosphate, pH 6.5, 2 mM genapol X-100, 1 .mu.M 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 .mu.L of the test compound in DMSO. The mixture is pre-incubated at room temperature (22.degree. C.) for 15 minutes prior to initiation of the enzymatic reaction by the addition of 20 .mu.L of a sonicated solution of 1 mM arachidonic acid (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 % inhibition. IC.sub.50 values are derived from 4-parameter least squares non-linear regression analysis of the log-dose vs % 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 PGE.sub.2 production in normal blood. These inhibitors are active only after incubation of human whole blood with LPS, which induces COX-2. This assay can be used to evaluate the inhibitory effect of selective COX-2 inhibitors on PGE.sub.2 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 B.sub.2 (TxB.sub.2) via activation of COX-1. Thus, the effect of test compounds on TxB.sub.2 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 PGE.sub.2 after LPS induction (COX-2) and TxB.sub.2 following blood clotting (COX-1) in the same assay.
Method
A. COX-2 (LPS-induced PGE.sub.2 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 2 mL blood aliquot to use as blank (basal levels of PGE.sub.2). The remaining blood is incubated with LPS (100 .mu.g/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 .mu.L aliquots of blood are incubated with either 2 .mu.L of vehicle (DMSO) or 2 .mu.L of a test compound at final concentrations varying from 10 nM to 30 .mu.M for 24 hours at 37.degree. C. At the end of the incubation, the blood is centrifuged at 12,000.times.g for 5 minutes to obtain plasma. A 100 .mu.L aliquot of plasma is mixed with 400 .mu.L of methanol for protein precipitation. The supernatant is obtained and is assayed for PGE.sub.2 using a radioimmunoassay kit (Amersham, RPA#530) after conversion of PGE.sub.2 to its methyl oximate derivative according to the manufacturer's procedure.
B. COX-1 (Clotting-induced TxB.sub.2 production)
Fresh blood is collected into vacutainers containing no anticoagulants. Aliquots of 500 .mu.L are immediately transferred to siliconized microcentrifuge tubes preloaded with 2 .mu.L of either DMSO or a test compound at final concentrations varying from 10 nM to 30 .mu.M. The tubes are vortexed and incubated at 37.degree. C. for 1 hour to allow blood to clot. At the end of incubation, serum is obtained by centrifugation (12,000.times.g for 5 min.). A 100 .mu.L aliquot of serum is mixed with 400 .mu.L of methanol for protein precipitation. The supernatant is obtained and is assayed for TxB.sub.2 using a enzyme immunoassay kit (Cayman, #519031) according to the manufacturer's instruction.
RAT PAW EDEMA ASSAY
Protocol
Male Sprague-Dawley rats (150-200 g) are fasted overnight and are given, po, either vehicle (1% methocel or 5% Tween 80) or a 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 (V.sub.0) is measured using a plethysmometer (Ugo-Basile, Italy) based on the principle of water displacement. The animals are then injected subplantarly with 50 ml of 1% carrageenan solution in saline (FMC Corp, Maine) into the paw using an insulin syringe with a 25-gauge needle (i.e. 500 mg carrageenan per paw). Three hr later, the paw volume (V.sub.3) is measured and the increases in paw volume (V.sub.3 -V.sub.O) are calculated. The animals are sacrificed by CO.sub.2 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.
LPS-Induced Pyrexia in Conscious Rats
Male Sprague-Dawley rats (150-200 g) were fasted for 16-18 h before use. At approximately 9:30 a.m., the animals were placed temporarily in plexiglass restrainers and their baseline rectal temperature was recorded using a flexible temperature probe (YSI series 400) connected to a digital thermometer (Model 08502, Cole Parmer). The same probe and thermometer were used for all animals to reduce experimental error. The animals were returned to their cages after the temperature measurements. At time zero, the rats were injected intraperitoneally with either saline or LPS (2 mg/kg, Sigma Chem) and the rectal temperature was remeasured at 5, 6 and 7 h following LPS injection. After the measurement at 5 h, when the increase in temperature had reached a plateau, the LPS-injected rats were given either the vehicle (1% methocel) or a test compound orally to determine whether the compound could reverse the pyrexia. Percent reversal of the pyrexia was calculated using the rectal temperature obtained at 7 h in the control (vehicle-treated) group as the reference (zero reversal) point. Complete reversal of pyrexia to the pre-LPS baseline value is taken as 100%.
LPS-Induced Pyrexia in Conscious Squirrel Monkeys
Temperature probes were surgically implanted under the abdominal skin in a group of squirrel monkeys (Saimiri sciureus) (1.0-1.7 kg). This allows for the monitoring of body temperature in conscious, unrestrained monkeys by a telemetric sensing system (Data Sciences International, Minnesota). The animals were fasted and were placed in individual cages for acclimatization 13-14 h before use. Electronic receivers were installed on the side of the cages which pick up signals from the implanted temperature probes. At approximately 9:00 a.m. on the day of the experiment, the monkeys were restrained temporarily in training chairs and were given a bolus I.V. injection of LPS, (6 mg/kg, dissolved in sterile saline). The animals were returned to their cages and body temperature was recorded continuously every 5 min. Two h after injection of LPS, when the body temperature had increased by 1.5-2.infin.C, the monkeys were dosed orally with either vehicle (1% methocel) or a test compound (3 mg/kg). One hundred minutes later, the difference between the body temperature and the baseline value was determined. Percent inhibition was calculated taking the value in the control group as 0% inhibition.
Acute Inflammatory Hyperalgesia Induced by Carrageenan in Rats
Experiments were performed using male Sprague Dawley rats (90-110g). Hyperalgesia to mechanical compression of the hind paw was induced by intraplantar injection of carrageenan (4.5 mg into one hind paw) 3 h previously. Control animals received an equivalent volume of saline (0.15 ml intraplantar). A test compound (0.3-30 mg/kg, suspended in 0.5% methocel in distilled water) or vehicle (0.5% methocel) was administered orally (2 ml/kg) 2 h after carrageenan. The vocalisation response to compression of the hind paw was measured 1 h later using a Ugo Basile algesiometer.
Statistical analysis for carrageenan-induced hyperalgesia was performed using one-way ANOVA (BMDP Statistical Software Inc.). Hyperalgesia was determined by subtracting the vocalisation threshold in saline injected rats from that obtained in animals injected with carrageenan. Hyperalgesia scores for drug-treated rats were expressed as a percentage of this response. ID.sub.50 values (the dose producing 50% of the maximum observed response) were then calculated by nonlinear least squares regression analysis of mean data using GraFit (Erithacus Software).
Adjuvant-Induced Arthritis in Rats
Seventy, 6.5-7.5 week old, female Lewis rats (body weight .about.146-170 g) were weighed, ear marked, and assigned to groups (a negative control group in which arthritis was not induced, a vehicle control group, a positive control group administered indomethacin at a total daily dose of 1 mg/kg and four groups administered with a test compound at total daily doses of 0.10-3.0 mg/kg) such that the body weights were equivalent within each group. Six groups of 10 rats each were injected into a hind paw with 0.5 mg of Mycobacterium butyricum in 0.1 ml of light mineral oil (adjuvant), and a negative control group of rats was not injected with adjuvant. Body weights, contralateral paw volumes (determined by mercury displacement plethysmography) and lateral radiographs (obtained under Ketamine and Xylazine anesthesia) were determined before (day -1) and 21 days following adjuvant injection, and primary paw volumes were determined before (day -1) and on days 4 and 21 following adjuvant injection. The rats were anesthetized with an intramuscular injection of 0.03-0.1 ml of a combination of Ketamine (87 mg/kg) and Xylazine (13 mg/kg) for radiographs and injection of adjuvant. The radiographs were made of both hind paws on day 0 and day 21 using the Faxitron (45 kVp, 30 seconds) and Kodak X-OMAT TL film, and were developed in an automatic processor. Radiographs were evaluated for changes in the soft and hard tissues by an investigator who was blinded to experimental treatment. The following radiographic changes were graded numerically according to severity: increased soft issue volume (0-4), narrowing or widening of joint spaces (0-5) subchondral erosion (0-3), periosteal reaction (0-4), osteolysis (0-4) subluxation (0-3), and degenerative joint changes (0-3). Specific criteria were used to establish the numerical grade of severity for each radiographic change. The maximum possible score per foot was 26. A test compound at total daily doses of 0.1, 0.3, 1, and 3 mg/kg/day, Indomethacin at a total daily dose of 1 mg/kg/day, or vehicle (0.5% methocel in sterile water) were administered per os b.i.d. beginning post injection of adjuvant and continuing for 21 days. The compounds were prepared weekly, refrigerated in the dark until used, and vortex mixed immediately prior to administration.
Two-factor (`treatment` and `time`) analysis of variance with repeated measures on `time` were applied to the % changes for body weight and foot volumes and to the rank-transformed radiographic total scores. A post hoc Dunnett's test was conducted to compare the effect of treatments to vehicle. A one-way analysis of variance was applied to the thymic and spleen weights followed by the Dunnett's test to compare the effect of treatments to vehicle. Dose-response curves for % inhibition in foot volumes on days 4, 14 and 21 were fitted by a 4-parameter logistic function using a nonlinear least squares' regression. ID.sub.50 was defined as the dose corresponding to a 50% reduction from the vehicle and was derived by interpolation from the fitted 4-parameter equation.
PHARMACOKINETICS IN RATS
Per Os Pharmacokinetics in Rats
Procedure:
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 10 mL/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 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, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h
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%: 10 mL/kg
Tween 80: 10 mL/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. ##EQU1##
Clearance rates are calculated from the following relation: ##EQU2##
The units of CL are mL/h.multidot.kg (milliliters per hour kilogram)
Intravenous Pharmacokinetics in Rats
Procedure:
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 CO.sub.2 sedation. The rats, one at a time, are placed in a primed CO.sub.2 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 CO.sub.2 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 I.V. dosing are either:
0, 5 min, 15 min, 30 min, 1 h, 2 h, 6 h
or 0, 5 min, 30 min, 1 h, 2 h, 4 h, 6 h.
Vehicles:
The following vehicles may be used in IV rat blood level determinations:
Dextrose: 1 mL/kg
Moleculosol 25%: 1 mL/kg
DMSO (dimethylsulfoxide): 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. ##EQU3##
Clearance rates are calculated from the following relation: ##EQU4##
The units of CL are mL/h.multidot.kg (milliliters per hour kilogram)
NSAID-INDUCED GASTROPATHY IN RATS
Rationale
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 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 .sup.51 Cr excretion after systemic injection of .sup.51 Cr-labeled red blood cells. Fecal .sup.51 Cr 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 .sup.51 Cr-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 .sup.51 Cr fecal excretion is calculated as a percent of total injected dose. .sup.51 Cr-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 400 Ci of sodium .sup.51 chromate for 30 min. at 37C. At the end of the incubation, the red blood cells are washed twice with 20 mL HBSS to remove free sodium .sup.51 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
Rationale
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 .sup.51 CrC.sub.13 solution. This isotopic ion can 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% methocel or 5% Tween 80 in H.sub.2 O vehicles, (3 mL/kg b.i.d.) or test compounds at doses from 1-100 mg/kg b.i.d. for 5 days. Intravenous .sup.51 Cr (5Ci/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 .sup.51 Cr 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.
Representative Biological Data
Compounds of the present invention are inhibitors of cyclooxygenase-2 and are thereby useful in the treatment of cyclooxygenase-2 mediated diseases as 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 E.sub.2 (PGE.sub.2) synthesized in the presence of arachidonic acid, cyclooxygenase-1 or cyclooxygenase-2 and a putative inhibitor. The IC.sub.50 values represent the concentration of putative inhibitor required to return PGE.sub.2 synthesis to 50% of that obtained as compared to the uninhibited control.
The results for certain of the biological assays may be seen in Table II.
TABLE II______________________________________ COX-2 (IC.sub.50 mM) COX-1 (IC.sub.50 mM)Example CHO HWB U-937 HWB______________________________________ 1 0.02 9.7 >10 -- 2 0.004 0.3 3 >100 3 0.002 0.2 1-3 -- 4 0.13 6.0 >50 -- 5 0.002 1.0 1-3 -- 6 0.004 6.0 10 -- 7 0.04 0.2 3-10 -- 8 >5 >33 >10 -- 9 0.03 0.1 1-3 -- 10 0.09 3.1 3-10 -- 11 0.07 <0.4 >10 -- 12 0.01 5.3 3-10 -- 13 0.10 2.7 10 -- 14 0.03 0.5 3-10 -- 15 0.03 26.6 >10 -- 16 0.24 0.7 >10 -- 17 0.40 5.3 >10 -- 18 0.08 23.4 >10 -- 19 0.92 3.2 >10 -- 20 0.09 10.4 >10 -- 21 0.11 5.3 >10 -- 22 0.03 10.8 >10 -- 23 0.03 7.5 >10 -- 24 0.02 10.3 >10 -- 25 0.08 4.7 >10 -- 26 0.01 1.7 3-10 -- 27 0.06 3.6 >10 -- 28 0.03 1.4 3-10 --______________________________________
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.degree. 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.degree. 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) 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 (liter(s)), mL (milliliters), g (gram(s)), mg (milligrams(s)), mol (moles), mmol (millimoles), eq (equivalent(s)), r.t.(room temperature), h (hour(s)), min (minute(s)).

EXAMPLE 1
3-(4-Methylsulfonyl)phenyl-2-pyrrolidin-1-yl-5-trifluoromethylpyridine
Step 1: 2-Amino-3-bromo-5-trifluoromethylpyridine
To a solution of 2-amino-5-trifluoromethylpyridine (9 g) in acetic acid (75 mL) at r.t. was added bromine (5.8 mL) slowly. After 1 h, the acid was neutralized by the careful addition of sodium hydroxide (10 N) at 0.degree. C. The resulting orange precipitate was dissolved in ether and washed successively with saturated potassium carbonate, saturated Na.sub.2 SO.sub.3 and brine, dried and concentrated. The residual solid was stirred vigorously in hexane for 1 h to provide, after filtration, the title compound as a white solid (10.2 g).
Step 2: 2-Amino-3-(4-methylthio)phenyl-5-trifluoromethylpyridine
A mixture of the bromide from Step 1,4-methylthiobenzene boronic acid (Li, et. al. J. Med. Chem. 1995, 38, 4570) (8.5 g), 2M aqueous sodium carbonate (60 mL) and palladium tetrakis(triphenylphosphine) (490 mg) in ethanol/benzene (100 mL, 1:1) was heated at reflux for 15 h. The mixture was cooled to r.t., diluted with water and extracted with ether. The organics were concentrated and the residue was subjected to stirred vigorously in ether/hexane for 1 h to provide, after filtration, the title compound (11.2 g) as a beige solid.
Step 3: 2-Amino-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
A mixture of 2-amino-3-(4-methylthio)phenyl-5-trifluoromethylpyridine (9.7 g), OsO.sub.4 (2 mL of a 4% solution in water) and NMO (13 g) in acetone/water (60 mL:5 mL) was stirred at r.t. overnight. Saturated aqueous Na.sub.2 SO.sub.3 was then added and the resulting mixture was stirred for 30 min. The acetone was evaporated and the resulting mixture was extracted with ether and ethyl acetate. The combined organics were washed with Na.sub.2 SO.sub.3, water, brine and then concentrated. The solid residue was stirred vigorously in hexane and ether for 1 h and then filtered to provide the title compound as a pale yellow solid (9.9 g).
Step 4: 2-Bromo-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
To a solution of 2-amino-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (7.2 g) in 48% HBr (25 mL) and bromine (3.5 mL) at 0C was carefully and slowly added sodium nitrite (3.9 g). The mixture was warmed to r.t. and stirred for 4 h. The mixture was treated with saturated sodium carbonate and extracted with ether. The organics were washed successively with saturated sodium bisulfite and brine, dried and concentrated. Flash chromatography (7:3 hexane/ethyl acetate) of the residue provided the title compound as a pale yellow solid (6.4 g).
Step 5: 3-(4-Methylsulfonyl)phenyl-2-pyrrolidin-1-yl-5-trifluoromethylpyridine
A mixture of pyrrolidine (0.5 mL), potassium carbonate (250 mg) and 2-bromo-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (150 mg) in DMSO (5 mL) was stirred at 65.degree. C. until tlc analysis indicated completion of the reaction (15 h). To the mixture was added 1 N HCl and the mixture was extracted with ethyl acetate. The organics were washed with saturated sodium bicarbonate and brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (1:1 hexane/ethyl acetate) or stirring the residual material vigorously in a suitable solvent (such as ether or ethyl acetate) provided the title compound as a white solid (93 mg), m.p. 184-187.degree. C.
EXAMPLE 2
3-(4-Methylsulfonyl)phenyl-2-piperidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Example 1, Step 5, but substituting piperidine for pyrrolidine, the title compound was obtained as a pale yellow solid, m.p. 159-160.degree. C.
EXAMPLE 3
5-Chloro-3-(4-methylsulfonyl)phenyl-2-piperidin-1-ylpyridine
Step 1: 2-Amino-3-bromo-5-chloropyridine
To a solution of 2-amino-5-chloropyridine (10 g) in acetic acid (75 mL) at r.t. was added bromine (2.6 mL) slowly. After 30 min, the acid was neutralized by the careful addition of sodium hydroxide (10 N) at 0.degree. C. The resulting orange precipitate was dissolved in ethyl acetate and washed successively with saturated potassium carbonate, saturated Na.sub.2 S.sub.2 O.sub.3 and brine, dried and concentrated. Flash chromatography (eluting with hexane/ethyl acetate, 3:1 v/v) of the residual solid provided the title compound as a pale yellow solid (14.8 g).
Step 2: 2-Amino-5-chloro-3-(4-methylsulfonyl)phenylpyridine
Following the procedures described in Example 1, Steps 2 and 3, but substituting 2-amino-3-bromo-5-chloropyridine from Step 1 (5 g) for 2-amino-3-bromo-5-trifluoromethylpyridine, the title compound was obtained as a white solid (5.3 g).
Step 3: 2.5-Dichloro-3-(4-methylsulfonyl)phenylpyridine
To a solution of 2-amino-5-chloro-3-(4-methylsulfonyl)phenylpyridine (1.5 g) in dioxane/water (15 mL) and concentrated HCl (1.5 mL) at 0.degree. C. was added a solution of sodium nitrite (580 mg) in 1.5 mL water. The mixture was stirred at 5.degree. C. for 1 h and then 10 N NaOH was added until the pH was basic. The mixture was diluted with water and extracted four times with ether. The combined organics were washed with 10% NaOH, dried and concentrated. The crude solid (1.4 g) and POCl.sub.3 (3 L) was heated at 110.degree. C. for 3 h in a steel bomb. The mixture was cooled to r.t., diluted carefully with water and neutralized with 10 N NaOH. The mixture was extracted with ether and the organics were washed with brine, dried and concentrated. The solid material was recrystallized from toluene to provide the title compound as an off-white solid (1.2 g).
Step 4: 5-Chloro-3-(4-methylsulfonyl)phenyl-2-piperidin-1-ylpyridine
A mixture of piperidine (250 mg), cesium carbonate (680 mg) and 2,5-dichloro-3-(4-methylsulfonyl)phenylpyridine (240 mg) in DMSO (3 mL) was stirred at 120.degree. C. until tlc analysis indicated completion of the reaction (15 h). To the mixture was added water and the mixture was extracted with ethyl acetate. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Chromatography (1:1 hexane/ethyl acetate) of the residual material provided the title compound as a white solid (101 mg), m.p. 184-187.degree. C.
______________________________________Elemental Analysis: Calculated: C, 58.20; H, 5.46; N, 7.98 Found: C, 58.06; H, 5.60; N, 7.85______________________________________
EXAMPLE 4
3-(4-Methylsulfonyl)phenyl-2-piperidin-1-ylpyridine
Step 1: 2-Chloro-3-(4-methylthio)phenylpyridine
To a solution of 2-chloro-3-hydroxypyridine (2 g) and triethylamine (5 mL) in CH2Cl2 (50 mL) at -78.degree. C. was added trifluoromethanesulfonic anhydride (2.8 mL) and was then warmed to r.t. Saturated ammonium chloride was added and the mixture was extracted with ether. The organics were washed with water and brine, dried and concentrated. The residual material containing the crude triflate, 4-methylthiobenzene boronic acid (Li, et. al. J. Med. Chem. 1995, 38, 4570) (2.6 g), 2M aqueous sodium carbonate (17 mL) and catalytic palladium tetrakis(triphenylphosphine) in ethanol/benzene (40 mL, 1:1) was heated at reflux for 3 h. The mixture was cooled to r.t., diluted with water and extracted with ether. The organics were concentrated and the residue was subjected to flash chromatography (85:15 hexane/ethyl acetate). The title compound was obtained as a solid (640 mg).
Step 2: 2-Chloro-3-(4-methylsulfonyl)phenylpyridine
Following the procedures described in Example 1, Step 3, but substituting 2-chloro-3-(4-methylthio)phenylpyridine from Step 1 for 2-amino-3-(4-methylthio)phenyl-5-trifluoromethylpyridine, the title compound was obtained as a white solid.
Step 3: 3-(4-Methylsulfonyl)phenyl-2-piperidin-1-ylpyridine
A mixture of piperidine (0.5 mL), potassium carbonate (100 mg) and 2-chloro-3-(4-methylthio)phenylpyridine (150 mg) in DMSO (1.5 mL) was stirred at 165.degree. C. until tlc analysis indicated completion of the reaction (15 h). Water was added and the mixture was extracted with ether. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (7:3 hexane/ethyl acetate) provided the title compound as a yellow. solid (80 mg).
______________________________________Elemental Analysis: Calculated: C, 64.53; H, 6.37; N, 8.85 Found: C, 64.71; H, 6.40; N, 8.47______________________________________
EXAMPLE 5
3-(4-Methylsulfonyl)phenyl-2-(1,2,3,6-tetrahydropyridinyl)-5-trifluoromethylpyridine
Following the procedures described in Example 1, Step 5, but substituting 1,2,3,6-tetrahydropyridine for pyrrolidine, the title compound was obtained as a solid, m.p. 149-149.5.degree. C.
EXAMPLE 6
2-(Homopiperidin-1-yl)-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
Following the procedures described in Example 1, Step 5, but substituting homopiperidine for pyrrolidine, the title compound was obtained as a solid, m.p. 161.4-163.5.degree. C.
EXAMPLE 7
3-(4-Methylsulfonyl)phenyl-2-((2S )-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine
Step 1: 2-Chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
To a solution of 2-amino-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (1.2 g) in water/concentrated HCl (9.5 mL:1 mL) at 0.degree. C. was added a solution of sodium nitrite (262 mg) in 5 mL water. The mixture was warmed to r.t. and stirred overnight. An additional 30 20 mg of sodium nitrite was added and after 3 h the heterogeneous mixture was filtered. A portion of the solid (250 mg) and POCl.sub.3 (110 mL) in DMF (2 mL) was heated at 70.degree. C. for 60 h. The mixture was cooled to r.t., diluted with water and extracted with ethyl acetate. The organics were washed with brine, dried and concentrated to provide the title compound as a pale yellow solid (270 mg) that was used as such in the subsequent reaction.
Step 2: 3-(4-Methylsulfonyl)phenyl-2-((2S)-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine
A mixture of (S)-2-pyrrolidinemethanol (400 mg), cesium carbonate (1 g) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (600 mg) in DMF (6 mL) was stirred at 80.degree. C. until tlc analysis indicated completion of the reaction (15 h). Water was added and the mixture was extracted with ether. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (3:7 hexane/ethyl acetate) provided the title compound as a white foam (470 mg).
______________________________________Elemental Analysis: Calculated: C, 53.99; H, 4.78; N, 7.00 Found: C, 54.13; H, 4.93; N, 6.89______________________________________
EXAMPLE 8
3-(4-Methylsulfonyl)phenyl-2-((2R)-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Example 7, Step 2, but substituting (R)-2-pyrrolidinemethanol for (S)-2-pyrrolidinemethanol, the title compound was obtained as a white foam.
______________________________________Elemental Analysis: Calculated: C, 53.99; H, 4.78; N, 7.00 Found: C, 53.75; H, 4.76; N, 6.78______________________________________
EXAMPLE 9
5-Chloro-3-(4-methylsulfonyl)phenyl-2-((2S)-2-hydroxyethyl)pyrrolidin-1-ylpyridine
A mixture of (S)-2-pyrrolidinemethanol (2 mL), CuI (16 mg) and 2,5-dichloro-3-(4-methylsulfonyl)phenylpyridine (510 mg) was stirred at 100.degree. C. until tlc analysis indicated completion of the reaction (15 h). Water was added and the mixture was extracted with ether. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (3:7 hexane/ethyl acetate) provided the title compound as a white foam (500 mg).
______________________________________Elemental Analysis: Calculated: C, 55.66; H, 5.22; N, 7.64 Found: C, 55.68; H, 5.32; N, 7.47______________________________________
EXAMPLE 10
3-(4-Methylsulfonyl)phenyl-2-((2S)-2-methoxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Example 7, Step 2, but substituting (S)-2-(methoxymethyl)pyrrolidine for (S)-2-pyrrolidinemethanol, the title compound was obtained as a white foam.
______________________________________Elemental Analysis: Calculated: C, 55.06; H, 5.11; N, 6.76 Found: C, 55.24; H, 4.94; N, 6.69______________________________________
EXAMPLE 11
3-(4-Methylsulfonyl)phenyl-2-((2S)-2-acetoxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine
To a solution of 3-(4-methylsulfonyl)phenyl-2-((2S)-2-hydroxymethyl)pyrrolidin-1-yl-5-trifluoromethylpyridine (200 mg) and DMAP (catalytic) in CH.sub.2 Cl.sub.2 (2 mL) at r.t. was added acetic anhydride (0.1 mL). After 2 h, water was added and the mixture was extracted with ether. The organics were dried and concentrated. Flash chromatography of the residual material (3:2 hexnae/ethyl acetate) provided the title compound as a white foam (160 mg).
______________________________________Elemental Analysis: Calculated: C, 54.29; H, 4.78; N, 6.33 Found: C, 54.09; H, 4.74; N, 6.17______________________________________
EXAMPLE 12
5-Chloro-3-(4-methylsulfonyl)phenyl-2-((2S)-2-methoxymethyl)pyrrolidin-1-ylpyridine
To a solution of 5-chloro-3-(4-methylsulfonyl)phenyl-2-((2S)-2-hydroxymethyl)pyrrolidin-1-ylpyridine (65 mg) and methyl iodide (0.1 mL) in DMF (5 mL) at r.t. was added potassium t-butoxide (0.5 mL of a 1 M solution in THF). After 10 min, saturated ammonium chloride was added and the mixture extracted with ethyl acetate. The organics were dried and concentrated. Flash chromatography of the residue (4:1 hexane/ethyl acetate) provided the title compound as a white foam.
.sup.1 H NMR (500 MHz, acetone-d.sub.6): d 1.5-1.63 (m, 1H), 1.6-1.83 (m, 2H), 1.97-2.05 (m, 1H), 2.60 (dt, 1H), 2.85 (dt, 1H), 3.15 (s, 3H), 3.30 (s, 3H), 3.40 (dd, 1H), 3.59 (dd, 1H), 4.48 (m, 1H), 7.55 (d, 1H), 7.71 (d, 2H), 7.98 (d, 2H), 8.11 (d, 1H).
EXAMPLE 13
3-(4-Methylsulfonyl)phenyl-2-(2-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine
A mixture of 2-(hydroxymethyl)piperidine (1 mL), CuI (10 mg) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (200 mg) was stirred at 100.degree. C. for 15 h. Water was added and the mixture was extracted with ether. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (1:1 hexane/ethyl acetate) provided the title compound as a white foam (50 mg).
______________________________________Elemental Analysis: Calculated: C, 55.06; H, 5.11; N, 6.76 Found: C, 54.74; H, 5.34; N, 6.51______________________________________
EXAMPLES 14 AND 15
(-)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine and (+)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine
Step 1: Racemic 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Example 13, but substituting 3-(hydroxymethyl)piperidine for 2-(hydroxymethyl)piperidine, the title compound was obtained as a white solid.
______________________________________Elemental Analysis: Calculated: C, 55.06; H, 5.11; N, 6.76 Found: C, 54.74; H, 5.15; N, 6.62______________________________________
Step 2: (-)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine and (+)-3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-yl-5-trifluoromethylpyridine
A portion (100 mg) of the racemic material obtained in Step 1 was subjected to HPLC using a chiral column (chiralpak AD from DAICEL; 2.times.25 cm) and an eluant of hexane/isopropanol (80:20) at a flow rate of 9 mL/min (10.times.10 mg injections). The first compound to be eluted (monitoring at 290 nm) with a retention time of 11.6 min was obtained as a white solid (40 mg) after concentration ([a].sub.D -78.degree.; c=0.205, CH.sub.2 Cl.sub.2). .sup.1 H NMR analysis of the derived Mosher's ester indicated >98% ee. The second eluting compound (retention time 12.5 min) was obtained as a white solid (15 mg) after concentration ([a].sub.D +72.2.degree.; c=0.18, CH.sub.2 Cl.sub.2). .sup.1 H NMR analysis of the derived Mosher's ester indicated .about.98% ee.
EXAMPLE 16
5-Chloro-3-(4-methylsulfonyl)phenyl-2-(3-hydroxymethyl)piperidin-1-ylpyridine
Following the procedures described in Example 9, but substituting 3-(hydroxymethyl)piperidine for (S)-2-pyrrolidinemethanol, the title compound was obtained as a pale yellow foam.
______________________________________Elemental Analysis: Calculated: C, 56.76; H, 5.56; N, 7.35 Found: C, 52.92; H, 5.75; N, 7.34______________________________________
EXAMPLE 17
3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl-3-methyl)piperidin-1-yl-5-trifluoromethylpyridine
Step 1: 3-Hydroxymethyl-3-methylpiperidine
To ethyl nipecotate (1.3 g) in THF (20 mL) at r.t was added potassium bis(trimethylsilyl)amide (18 mL of a 0.5 M solution in toluene). After 1 h, methyl iodide (0.5 mL) was added and the mixture was stirred for 15 h. Water was added and the mixture extracted with ether. The organics were washed with brine, dried and concentrated. The residual material (1.3 g) was dissolved in THF (20 mL) and treated with lithium aluminum hydride (8.7 mL of a 1 M solution in THF) at r.t. After 15 h, the mixture was cooled to -5.degree. C. and aqueous sodium potassium tartrate was added followed by concentrated NH.sub.4 OH, 10 N NaOH and the resulting mixture was stirred for 30 min. The mixture was filtered through anhydrous sodium sulfate and the filtrate was concentrated from toluene twice. The residual oil (1 g), containing the title compound, was used without further purification in Step 2.
Step 2: 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl-3-methyl)piperidin-1-yl-5-trifluoromethylpyridine
A mixture of crude 3-hydroxymethyl-3-methylpiperidine from Step 1 (500 mg) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (330 mg) was stirred at 100.degree. C. for 3 h. Water was added and the mixture was extracted with ethyl acetate. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (2:3 hexane/ethyl acetate), followed by stirring the semi-purified material vigorously in ether/hexane, provided the title compound as a white solid (250 mg).
______________________________________Elemental Analysis: Calculated: C, 56.06; H, 5.41; N, 6.54 Found: C, 55.83; H, 4.70; N, 6.42______________________________________
EXAMPLE 18
3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)homopiperidin-1-yl-5-trifluoromethylpyridine
Step 1: N-Benzyl e-caprolactam
To a solution of e-caprolactam (28.3 g) in THF (500 mL) and DMF (20 mL) at r.t. was added sodium hydride (12 g of 60% in oil) portionwise. After the addition was complete, benzyl bromide (29.7 mL) was added dropwise and upon completion, the mixture was stirred for 15 h. To the mixture was carefully added saturated ammonium chloride and the resulting mixture was extracted twice with ethyl acetate. The organics were washed with water and brine, dried and concentrated. The title compound was obtained as a white solid and used in Step 2 without further purification.
Step 2: 3-(Hydroxymethyl)homopiperidine
To a solution of LDA (prepared at 0C from 5.3 mL of diisopropylamine and 15.8 mL of 2.4 M n-BuLi in hexanes) in THF (150 mL) at -78.degree. C. was added N-benzyl e-caprolactam (7 g) from Step 1. The mixture was warmed to -40.degree. C. and then cooled to -98.degree. C. To the cold solution was added ethyl formate (5 eq) and then the mixture was warmed to r.t. Saturated ammonium chloride was added and the resulting mixture was extracted twice with ethyl acetate. The organics were washed with water and brine, and then filtered through a pad of silica gel. The filtrate was concentrated to provide the formylated product (6 g) that was used as such. The residual material was dissolved in THF (100 mL) and treated with lithium aluminum hydride (2 eq of 1 M solution in THF) at r.t. After 15 h, the mixture was cooled to -5.degree. C. and aqueous sodium potassium tartrate was added followed by concentrated NH.sub.4 OH, 10 N NaOH and the resulting mixture was stirred for 30 min. The mixture was filtered through anhydrous sodium sulfate and the filtrate was then filtered through a pad of silica gel. The filtrate was concentrated to provide the reduced product (2.2 g) that was used as such. A mixture of the crude material and 10% Pd--C (200 mg) in ethanol (100 mL) was stirred under an atmosphere of hydrogen (1 atm) for 2 days. The mixture was filtered through a pad of Celite and the filtrate was concentrated. Flash chromatography of the residual material (ethyl acetate) provided the title compound as an oil that was used as such in Step 3.
Step 3: 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxymethyl)homopiperidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Example 13, but substituting 3-(hydroxymethyl)homopiperidine for 2-(hydroxymethyl)piperidine, the title compound was obtained as a white solid.
______________________________________Elemental Analysis: Calculated: C, 56.06; H, 5.41; N, 6.54 Found: C, 55.86; H, 5.30; N, 6.44______________________________________
EXAMPLE 19
3-(4-Methylsulfonyl)phenyl-2-(2-(2-hydroxvethyl))piperidin-1-yl-5-trifluoromethylpyridine
A mixture of 2-piperidineethanol (1.5 g), Cul (20 mg) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (336 mg) was stirred at 130.degree. C. for 15 h. Water was added and the mixture was extracted with ether. The organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (1:1 hexane/ethyl acetate) provided the title compound as a white solid (56 mg), m.p. 136-137.degree. C.
EXAMPLES 20 AND 22
3-(4-Methylsulfonyl)phenyl-2-(4-oxo)piperidin-1-yl-5-trifluoromethylpyridine and 3-(4-Methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine
Step 1: 3-(4-Methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine
A mixture of 4-hydroxypiperidine (1 g), CuI (20 mg), diisopropylethylamine (1 mL) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (336 mg) was stirred at 100.degree. C. for 15 h. 1 N HCl and CH.sub.2 Cl.sub.2 were added and the mixture was extracted with ethyl acetate and ether. The combined organics were washed with saturated ammonia and brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (1:1 hexane/ethyl acetate) provided the title compound (Example 22) as a white solid (147 mg), m.p. 185-186.5.degree. C.
Step 2: 3-(4-Methylsulfonyl)phenyl-2-(4-oxo)piperidin-1-yl-5-trifluoromethylpyridine
A mixture of 3-(4-methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine from Step 1 (400 mg), 3A.degree. molecular sieves (1 g), TPAP (catalytic) and NMO (234 mg) in acetonitrile (10 mL) was stirred for 15 h at r.t. The mixture was filtered and the filtrate was concentrated. Flash chromatography (1:1 hexane/ethyl acetate), followed by stirring the semi-purified material vigorously in ether, provided the title compound (Example 20) as a beige solid (77 mg).
______________________________________Elemental Analysis: Calculated: C, 54.27; H, 4.30; N, 7.03 Found: C, 53.98; H, 4.23; N, 6.91______________________________________
EXAMPLES 21 AND 23
3-(4-Methylsulfonyl)phenyl-2-(3-oxo)piperidin-1-l-5-trifluoromethylpyridine and 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine
Step 1: 3-(4-Methylsulfonyl)phenyl-2-(3-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Examples 20 and 22, Step 1, but substituting 3-hydroxypiperidine for 4-hydroxypiperidine, the title compound (Example 23) was obtained as a white solid.
______________________________________Elemental Analysis: Calculated: C, 53.99; H, 4.78; N, 7.00 Found: C, 53.72; H, 5.00; N, 7.10______________________________________
Step 2: 3-(4-Methylsulfonyl)phenyl-2-(3-oxo)piperidin-1-yl-5-trifluoromethylpyridine
Following the procedures described in Examples 20 and 22, Step 2, but substituting 3-(4-methylsulfonyl)phenyl-2-(3-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine from Step 1 for 3-(4-methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine, the title compound (Example 21) was obtained as a beige solid, m.p. 176-176.5.degree. C.
EXAMPLE 24
2-(4.4-Difluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
A mixture of 3-(4-methylsulfonyl)phenyl-2-(4-oxo)piperidin-1-yl-5-trifluoromethylpyridine (480 mg) and DAST (0.32 mL) in benzene (12 mL) was heated at reflux for 3 h. Saturated sodium carbonate was carefully added and the mixture was extracted with ethyl acetate. The combined organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (3:2 hexane/ethyl acetate), followed by stirring the semi-purified material vigorously in ether, provided the title compound as a white solid (340 mg).
______________________________________Elemental Analysis: Calculated: C, 51.43; H, 4.08; N, 6.66 Found: C, 51.62; H, 3.88; N, 6.57______________________________________
EXAMPLE 25
2-(3,3-Difluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
Following the procedures described in Examples 24, but substituting 3-(4-methylsulfonyl)phenyl-2-(3-oxo)piperidin-1-yl-5-trifluoromethylpyridine for 3-(4-methylsulfonyl)phenyl-2-(4-oxo)piperidin-1-yl-5-trifluoromethylpyridine, the title compound was obtained as an off-white solid, m.p. 152.5-153.5.degree. C.
EXAMPLE 26
2-(4-Fluoro)piperidin-1-yl-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine
To a solution of 3-(4-methylsulfonyl)phenyl-2-(4-hydroxy)piperidin-1-yl-5-trifluoromethylpyridine (150 mg) in CH.sub.2 Cl.sub.2 (1.9 mL) at -78.degree. C. was added DAST (74 mL). The mixture was warmed to r.t. and then saturated sodium carbonate was carefully added. The mixture was extracted with ethyl acetate and the combined organics were washed with brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (3:2 hexane/ethyl acetate), followed by stirring the semi-purified material vigorously in ether, provided the title compound as a white solid (115 mg), m.p. 136-137.5.degree. C.
EXAMPLE 27
3-(4-Methylsulfonyl)phenyl-2-morpholin-4-yl-5-trifluoromethylpyridine
Following the procedures described in Example 13, but substituting morpholine for 2-(hydroxymethyl)piperidine, the title compound was obtained as a white solid, m.p. 159-160.degree. C.
EXAMPLE 28
3-(4-Methylsulfonyl)phenyl-2-thiomorpholin-4-yl-5-trifluoromethylpyridine
A mixture of thiomorpholine (350 mg), CuI (20 mg), N-ethyl morpholine (2 mL) and 2-chloro-3-(4-methylsulfonyl)phenyl-5-trifluoromethylpyridine (500 mg) was stirred at 128.degree. C. for 15 h. 1 N HCl and CH.sub.2 Cl.sub.2 were added and the mixture was extracted with ethyl acetate and ether. The combined organics were washed with saturated ammonia and brine, dried (MgSO.sub.4) and concentrated. Flash chromatography (1:1 hexane/ethyl acetate), followed by stirring the semi-purified material vigorously in ether, provided the title compound as a white solid (460 mg).
______________________________________Elemental Analysis: Calculated: C, 50.74; H, 4.26; N, 6.96 Found: C, 50.56; H, 4.34; N, 6.90______________________________________

Number	Name	Date
4757073	New et al.	Jul 1988
5480568	Pawloski et al.	Jan 1996
5593994	Batt et al.	Jan 1997
5686470	Weier	Nov 1997

Number	Date	Country
0 591030	Apr 1994	EPX
0 647639	Apr 1995	EPX
0 754687	Jan 1997	EPX
44 19 247	Dec 1995	DEX
WO 9413635	Jun 1994	WOX
WO 9610012	Apr 1996	WOX
WO 9616934	Jun 1996	WOX
WO 9624584	Aug 1996	WOX

2-aminopyridines as inhibitors of cyclooxygenase-2

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Entry
Silverman, The Organic Chemistry of Drug Design and Drug Action, pp. 15-22, 1992.
New, J.S., et al., J. of Med. chem., vol. 31, No. 3, pp. 618-624, 1988.
Charushin, V. N., et al., J. Org. Chem., vol. 48, No. 16, pp. 2667-2671, 1983.