PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(51) International Patent Classification 5 :
`
`(11) International Publication Number:
`
`WO 95/01980
`
`C07D 471/04, A6lK 3]/435 // (C07D
`471/04, 231:00, 221:00)
`
`A1
`
`‘
`
`(43) International Publication Date:
`
`19 January 1995 (l9.01.95)
`
`(21) International Application Number:
`
`PCT/IB94/00156
`
`(22) International Filing Date:
`
`16 June 1994 (16.06.94)
`
`(81) Designated States: AU, BR, CA, CN, CZ, I-l'U, JP, KR, NO,
`NZ, PL, RU, US, European patent (AT, BE, CH, DE, DK,
`ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE).
`
`(30) Priority Data:
`08/088,292
`
`6 July 1993 (O6.07.93)
`
`Published
`With international search report.
`
`(60) Patent Application or Grant
`(63) Related by Continuation
`US
`Filed on
`
`08/088,292 (CON)
`6 July 1993 (06.07.93)
`
`(71) Applicant (for all designated States except US): PFIZER INC.
`[US/US]; 235 East 42nd Street, New York, NY 10017 (US).
`
`(72) Inventor; and
`(75) Inventor/Applicant (for US only): DUPLANTIER, Allen,
`Jacob [US/US]; 450 Pmnpkin Hill Road, Ledyard, CT 06339
`(US).
`
`(74) Agents: SPIEGEL, Allen, J. et al.; Pfizer Inc., Patent Dept,
`235 East 42nd Street, New York, NY 10017 (US).
`
`(54) Title: BICYCLIC TETRAHYDRO PYRAZOLOPYRIDINES
`
`(57) Abstract
`
`R1
`
`Compounds of formula
`(I) wherein R1, R2, R3 and X
`are as defined. The compounds
`of
`formula
`(I)
`and
`the
`pharmaceutically
`acceptable
`salts
`thereof
`are useful
`in
`inhibiting
`phosphodiesterase
`(PDE)
`type
`IV and
`the
`production of tumor necrosis
`factor
`(TNF)
`and
`in
`the
`treatment of asthma, arfliritis,
`bronchitis, chronic obstructive
`airways
`disease,
`psoriasis,
`allergic rhinitis, dermatitis and other inflamgnatory diseases, AIDS, septic shock and other diseases involving the production of TNF.
`
`\
`N/
`
`|
`
`3
`
`N |R
`
`CFAD EX 1006
`
`CFAD EX 1006
`
`

`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international
`applications under the PCI‘.
`
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`con: d‘IVoiIe
`
`EEEEEEBBQEQESQ
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungary
`
`MR
`MW
`NE
`NL
`N0
`
`
`
`§E§§§‘2EE*=§§?5§E‘=i5E
`
`Democratic People's Republic
`of Korea
`Republic of Korea
`Kazakhstan
`Liechtenstein
`Sri Lanka
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`
`Mallntanla‘‘
`Malawi
`Nigu
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Fedaation
`Sudan
`Sweden
`Slovenia
`Slovakia
`Senegal
`Chad
`Togo
`Tajikistan
`‘Ilinidad and Tobago
`Ukraine
`United States of Amaica
`Uzbekistan
`Viet Nam
`
`

`
`wo 95/01980
`
`'
`
`PCT/IB94/00156
`
`-1-
`
`BlCYCLlC TETRAHYDRO PYRAZOLOPYRIDINES
`
`Background of the Invention
`
`This invention relates to a series of bicyclic tetrahydro pyrazolopyridines which
`
`are selective inhibitors of phosphodiesterase (PDE) type IV or the production of tumor
`
`necrosis factor (hereinafter TNF) and as such are useful in the treatment of asthma,
`
`arthritis, bronchitis, chronic obstructive ain/vays disease, psoriasis, allergic rhinitis,
`
`dermatitis and other inflammatory diseases; and AIDS, septic shock and other diseases
`
`involving the production of TNF.
`
`This invention also relates to a method of using such compounds in. the
`
`treatment ofthe above diseases in mammals, especially humans and to pharmaceutical
`
`compositions useful therefor.
`
`Since the recognition that cyclic AMP is an intracellular second messenger
`
`(E.W. Sutherland, and T. W. Flall, Pharmacol. Flev., 1960, _1_g_, 265), inhibition of the
`
`phosphodiesterases has been a target for modulation and, accordingly, therapeutic
`
`intervention in a range of disease processes. More recently, distinct classes of PDE
`
`have been recognized (J.A. Beavo and D. H. Reifsnyder, '_l'fl°_§, 1990, 1_1_, 150), and their
`
`selective inhibition has led to improved drug therapy (C.D. Nicholson, R. A. Challiss and
`
`M. Shahld, _'[_ifl§, 1991, g, 19). More particularly, it has been recognized that inhibition
`
`of PDE type lV can lead to inhibition of inflammatory mediator release (M.W. Verghese
`
`et al., J. Mol. Cell Cardiol., 1989, 1_2_ (Suppl.
`
`II), S 61) and airway smooth muscle
`
`relaxation (T. J. Torphy in Directions for New Anti—Asthma Drugs, eds S. Fl. O'Donnell
`
`and C. G. A. Persson, 1988, 37, Birkhauser-Verlag). Thus, compounds that inhibit PDE
`
`type IV, but which have poor activity against other PDE types, would inhibit the release
`
`of
`
`inflammatory mediators and relax airway smooth muscle without causing
`
`cardiovascular effects or antiplatelet effects.
`
`' TNF is recognized to be involved in many infectious and auto-immune diseases
`
`(W. Friers, FEBS Letters, 1991, g§§, 199). Furthermore, it has been shown that TNF is
`
`the prime mediator of the inflammatory response seen in sepsis and septic shock (C.E.
`
`Spooner et al., Clinical Immunology g1_d_ Immunogathology, 1992, §_2_, S11).
`
`

`
`W0 95/01980
`
`PCT/IB94/00156
`
`-2-
`
`Summary of the Invention
`
`The present invention relates to compounds of the formula
`
`R1
`
`and the pharmaceutically acceptable salts thereof; wherein Fl‘ is hydrogen, (C‘-C7)alkyl,
`
`(C’-C°)alkenyl, (C3-C5)cycloalkyl or methylene (C3-C5)cycloalky| wherein each alkyl or
`
`alkenyl group may be optionally substituted with up to two (C‘-C’)alkyl ortrifluoromethyl
`
`groups or up to three halogens; X is oxygen or two hydrogen atoms; Fl’ and R’ are
`
`each independently selected from the group consisting of hydrogen, (C‘-C“)alkyl, (C'-
`
`C“‘)alkoxy, (C2-C7)a|keny|, a (C‘-C7)heterocyclic group containing oxygen, sulphur, S0,
`
`or NR5 wherein R5 is hydrogen or (C‘-C‘)alkyl, or a group of the formula
`
`V
`
`—<Y>b5<Z>c
`
`(124),,
`
`11
`
`wherein a is an integer from 1 to 5; b and c is 0 or 1; Fl‘ is hydrogen, hydroxy, (C'-
`
`C5)a|ky|,
`
`(C7-C5)alkenyl, (C’-C“)alkoxy, (C3-C°)cyc|oalkoxy,‘halogen, trifluoromethyl,
`
`CO,R°, CONRER7, NFl°R’, NO, or S0,NFl°R7 wherein Fl“ and R’ are each independently
`
`hydrogen or (C‘-C")alkyl; wherein Z is oxygen, sulphur, S0, or NR‘ wherein R’ is
`
`hydrogen or
`
`(C‘-C“)alkyl; and Y is
`
`(C‘-C5)alky|ene or
`
`(C3-C°)alkeny| optionally
`
`substituted with up to two (C‘-C7)alkyl or (C3-C7)cyc|oalkyl groups; or a group of the
`
`formula
`
`R9
`
`*3
`
`p
`
`

`
`WO 95/01980
`
`PCT/IB94/00156
`
`.3.
`
`wherein p is an integer from 1 to 3, W is oxo or hydroxy, R’ is (C‘-C’)all<yl; wherein
`
`each said alkyl, alkenyl. cycloalkyl, alkoxyalkyl or heterocyclic group may be optionally
`
`substituted with one to fourteen, preferably one to five, of the group consisting of (C‘-
`
`C’)alkyl, trifluoromethyl or halogen with the proviso that when R‘ is ethyl and R’ is 4-
`
`methylphenyl, R’ cannot be hydrogen, methyl, phenyl, 4-fluorophenyl or 2-pyridyl and
`
`with the proviso that when R’ is 4-methylphenyl and R’ is 4-fluorophenyl, R‘ cannot be
`
`phenyl, methyl or n-propyl and with the proviso that when R‘ is ethyl and R’ is phenyl,
`
`Ft’ cannot be 4-chlorophenyl. 4-fluorophenyl or 4-methylphenyl and with the proviso that
`
`when R‘ is ethyl and Ft’ is 4-methoxyphenyl, R3 cannot be 4-fluorophenyl.
`
`In one embodiment. the invention relates to a compound of formula I wherein
`
`R‘
`
`is (C‘-C3)a|kyl and R’ and R3 are each independently selected from the group
`
`consisting of (C3-C’)cycloalkyl, (C‘-C7)heterocyc|ic group containing S0, or a group of
`
`the formula
`
`wherein a is an integer from 1 to 5 and Ft‘ is hydrogen, hydroxy, (C‘-C5)alkyl, (C‘-
`
`C5)alkoxy or halogen.
`
`In another embodiment,
`
`the invention relates to a compound of formula I
`
`wherein R‘
`
`is ethyl or isopropyl; R’ is phenyl, 2—methylphenyI, 3-methylphenyl, 2-
`
`methoxyphenyl, 3-methoxyphenyl or 3-trilluoromethylphenyl and R3 is cyclobutyl,
`
`cyclopentyl, cyclohexyl, 3-sulfolanyl, 4-fluorophenyl or 3,4-dichlorophenyl.
`
`The present invention further relates to a pharmaceutical composition for the
`
`inhibition of phosphodiesterase (PDE) type IV and the production of tumor necrosis
`
`factor (TNF) comprising a pharmaceutically effective amount of a compound according
`
`to formula I and the pharmaceutically acceptable salts thereof, and a pharmaceutically
`
`acceptable carrier.
`
`The present
`
`invention further
`
`relates to a method for
`
`the inhibition of
`
`phosphodiesterase (PDE) type IV and the production of tumor necrosis factor (TNF)
`
`comprising administering to a patient an effective amount of a compound according to
`
`formula I and the pharmaceutically acceptable salts thereof.
`
`

`
`WO 95/01980
`
`PCT/IB94/00156
`
`.4-
`
`The present invention further relates to a method of treating an inflammatory
`
`condition in mammals which
`
`comprises
`
`administering to said mammal
`
`an
`
`antiinflammatory amount of a compound of the formula I and the pharmaceutically
`
`acceptable salts thereof.
`
`The present invention further relates to a pharmaceutical composition for the
`
`treatment of asthma, arthritis, bronchitis, chronic obstructive ain/vays disease, psoriasis,
`
`allergic rhinitis, dermatitis and other inflammatory diseases, AIDS, septic shock and
`
`other diseases involving the production of TNF comprising a pharmaceutically effective
`
`amount of a compound according to formula I and the pharmaceutically acceptable
`
`salts thereof together with a pharmaceutically acceptable carrier.
`
`This invention further relates to a method of treating or preventing a condition
`
`selected from the group consisting of asthma, arthritis, bronchitis, chronic obstructive
`
`ain/vays disease, psoriasis, allergic rhinitis, dermatitis and other inflammatory diseases,
`AIDS, septic shock and other diseases involving the production of TNF comprising
`
`administering to a patient an effective amount of a compound according to formula I
`
`and the pharmaceutically acceptable salts thereof.
`
`Specific preferred compounds of the invention are:
`
`3-ethyl-1-(4-methoxyphenyl)-6-phenyl-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo-
`
`[3,4-c]pyridine;
`
`3-ethyl-1-cyclopentyl-6-pheny|—7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo-
`
`[3,4-c]pyridine;
`
`3-ethyl-1-(3,4-dichIorophenyl)-6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1 -cycIopentyl-6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl—1—(4-fluorophenyl)-6-(2-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1 -cyclopentyl-6-(3-methylphenyl)-7-oxo4,5,6,7-tetrahydro-1H-pyrazo|o[3,4-
`
`c]pyridine;
`
`3-ethyl-1-cyclopentyl-6-(3-trifluoromethylphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1-cyc|ohexy|-6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`

`
`WO 95/01980
`
`PCT/IB94/00156
`
`-5-
`
`3-isopropyl-1 -cyclopentyl-6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1-cyclobutyl—6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3—ethy|—1-cyclopentyl-6-phenyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1 -cyclopentyl-6-(2-methylphenyl)-7-oxo—4,5,6,7-tetrahydro-1 H-pyrazolo[3,4-
`
`c]pyridine;
`
`3-ethyl-1 -(3-suIfolanyl)-6-(3-methylphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1-(3-suIfolanyl)-6-(3-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazo|o[3,4-c]pyridine;
`
`3-ethy|—1-cyclobutyl-6—(3-methylphenyl)-7-oxo4,5,6,7-tetrahydro-1H-pyrazolo[3,4-
`
`c]pyridine;
`
`3-ethyl-1 -(3-sulfoIanyl)-6-(3-trifluoromethylphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`_
`
`3-ethyl-1 -cyclobutyl-6-(3-trifluoromethylphenyl)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine;
`
`3-ethyl-1-cyclobutyl-6-(2-methylphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyraz0|o[3,4—‘
`
`c]pyridine.
`
`Detailed Description of the Invention
`
`Theterm "halogen", as used herein, unless otherwise indicated, includes chloro,
`
`fluoro and bromo.
`
`Unless indicated otherwise, the alkyl, alkoxy and alkenyl groups referred to
`
`herein may be straight chained or if comprising three or more carbons may be straight
`
`chained, branched, cyclic or a combination of cyclic and branched or straight chained
`moieties.
`
`The "inflammatory diseases" which can be treated according to this invention
`
`include, but are not
`
`limited to asthma, chronic obstructive pulmonary disease,
`
`bronchitis and arthritis.
`
`Fl‘, R2 and R3, as used herein, unless otherwise indicated, are as defined above
`
`with reference to formula I.
`
`The following reaction schemes illustrate, but are not limiting to the preparation
`
`of the compounds of the present invention.
`
`

`
`W0 95/01980
`
`~
`
`PCT/IB94/00156
`
`SCHEHE 1
`
`SCHEME 2
`
`

`
`WO 95/01980
`
`PCT/IB94/00156
`
`-7.
`
`in Reaction 1 of Scheme 1, the 2—pyrro|idinone compound of formula IV is
`
`converted to the corresponding N-(aryl)-2-pyrrolidone compound V wherein "aryl" is a
`
`group of the formula II by reacting IV with an aryl halide neat in the presence of copper
`
`power and potassium carbonate. Suitable aryl halides include 1-iodo- or 1-bromo- 4-
`
`methoxybenzene,
`
`3-methoxybenzene,
`
`2-methoxybenzene,
`
`3-methylbenzene,
`
`4-
`
`methylbenzene, 2-methylbenzene, 3-trifluoromethylbenzene, 2-trifluoromethylbenzene,
`
`3,4-dimethoxybenzene or 3-cyclopentoxy-4-methoxybenzene. The reaction temperature
`
`will generally be in the range of about 110°C to about 170°C, preferably about 150°C,
`
`for a time period of about 14 hours to about 22 hours, preferably about 18 hours, under
`inert reaction conditions.
`
`In Reaction g of Scheme 1, R‘ halide is added to a suspension of magnesium
`
`in an anhydrous aprotic solvent. The reaction mixture is heated to reflux until all the
`
`magnesium is consumed and thereafter cooled to atemperature between about -15°C
`
`to about 15°C, preferably about 0°C. The N-(aryl)-2-pyrrolidone compound of formula
`
`V is then added and the reaction mixture is warmed to room temperature while being
`
`stirred for a time period between about 1.5 hours to about 2.5 hours, preferably about
`
`2 hours.
`
`Suitable alkyl halides
`
`include bromomethane, bromoethane or
`
`bromopropane. The preferred anhydrous aprotic solvent is anhydrous ether. Upon
`
`completion of the reaction, the desired intermediate may be isolated in a conventional
`
`manner, e.g., by first washing the combined organics with water and brine, then drying
`
`over sodium sulfate, filtering and concentrating under reduced pressure to afford a
`
`readily-recoverable precipitate in the form of a white solid.
`
`The
`
`above
`
`precipitate
`
`is
`
`converted
`
`to
`
`the
`
`corresponding
`
`1,2,5,6-
`
`tetrahydropyridine compound of formula V! by dispersing the precipitate in a mixture
`
`of a non—po|ar aprotic solvent and base. Upon vigorous stirring, ethyl oxalyl chloride
`
`is added and the reaction mixture is heated to reflux for a time period between about
`
`1.5 hours to about 4.5 hours, preferably about 3.0 hours. The preferred non-polar
`
`aprotic solvent is benzene and the preferred base is sodium hydroxide. The solvents
`
`are removed and the resulting residue is treated with a solution of sodium alkoxide in
`
`ethanol. After heating at reflux for a time period between about 1 hour and about 3
`
`hours, preferably about 1.5 hours, the mixture is concentrated under reduced pressure
`
`and acidified to pH=3 with hydrochloric acid.
`
`

`
`W0 95/01980
`
`PCT/IB94/00156
`
`-8-
`
`In Reaction Q of Scheme 1, the compound of formula VI is converted to the
`
`corresponding 3-methoxy-1,2,5,6-tetrahydropyridine compound VII by heating to reflux
`
`a reaction mixture of VI and 3-methyl-1-p-tolyltriazene in an aprotic solvent. The
`
`preferred aprotic solvent is 1,2-dichloroethane. The time period for the reaction is
`
`between about 30 minutes to about 120 minutes, preferably about 45 minutes.
`
`In Reaction 1 of Scheme 2, the 1,2,5,6-tetrahydropyridine compound of formula
`
`VIII, wherein R5 is hydrogen or methyl,
`
`is converted to the corresponding 4,5,6,7-
`
`tetrahydro-7-oxo-1H-pyrazolo[3,4-c]pyridine compound IX by reacting VIII with a
`
`hydrazine of the formula FPHNNH2. Both derivatives of the compound of formula VIII,
`
`3-hydroxy and 3-methoxy, may be used as starting materials under one of three
`
`different sets of reaction conditions.
`
`Under one set of reaction conditions, the 1,2,5,6-tetrahydropyridine compound
`
`of formula VIII is converted to the corresponding compound of formula IX by reacting
`
`VIII with a hydrazine hydrochloride and sodium alkoxide in an anhydrous polar protic
`
`solvent. The preferred sodium alkoxide is sodium methoxide and the preferred
`
`anhydrous polar protic solvent is anhydrous ethanol. The reaction mixture is heated
`
`to reflux for a time period between about 9 hours to about 15 hours, preferably about
`12 hours.
`
`Under a second set of reaction conditions,
`
`the 1,2,5,6-tetrahydro-pyridine
`
`compound VIII is converted to the corresponding compound of formula IX by reacting
`
`VlI_l with hydrazinobenzoic acid in an anhydrous polar protic solvent, preferably ethanol.
`
`The reaction mixture is heated to reflux for a time period between about 16 hours to
`
`about 24 hours, preferably about 20 hours. The compound IX so formed may be
`
`further reacted to give the corresponding 1-(4—benzamide)-7-oxo-4,5,6,7-tetrahydro-1 H-
`
`pyrazolo[3,4-c]pyridine compound by reacting IX with sodium methoxide in a polar
`
`protic solvent, preferably methanol, for a time period between about 15 minutes to
`
`about 45 minutes, preferably 30 minutes. The polar protic solvent is removed under
`
`reduced pressure,
`
`the solid residue is suspended in a non-polar aprotic solvent,
`
`perferably benzene, and thereafter, the non-polar solvent is removed under reduced
`
`pressure. The resulting dry solid is suspended in cold ether and treated with oxalyl
`
`chloride and N,N-dimethylformamide and allowed to stir for a time period between
`
`about 30 minutesto about 90 minutes, preferably 60 minutes. The solvent is then
`
`removed and the crude residue is dissolved in dry tetrahydrofuran. The resulting
`
`

`
`WO 95/01980
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`PCT/IB94/00156
`
`-9-
`
`solution is added dropwise to stirred ammonium hydroxide at a temperature between
`
`about -10°C to about 10°C, preferably 0°C.
`
`Under a third set of
`
`reaction conditions,
`
`the 1,2,5,6-tetrahydropyridine
`
`compound of formula VIII is converted to the corresponding compound of formula IX
`
`by reacting Vlll with a hydrazine hydrochloride in a polar protic solvent, preferably
`
`methanol. The reaction mixture is heated to a temperature between about 70°C to
`
`about 110°C, preferably about 90°C, under a gentle stream of nitrogen until all of the
`
`solvent is removed. The neat mixture is then heated to a temperature between about
`
`120°C to about 180°C, preferably about 150°C, for a time period between about 30
`
`minutes to about 90 minutes, preferably 60 minutes.
`
`The compounds
`
`so formed of
`
`formula IX may be converted to the
`
`corresponding 6-Fl?-4,5,6,7-tetrahydro-7-oxo-1H-pyrazolo [3,4-c]pyridine compound,
`
`wherein R’ is other than the group of formula II, by reacting a solution of IX in a polar
`
`aprotic solvent, preferably acetonitrile, with a solution of ammonium cerium (IV) nitrate
`
`in water at a temperature between about -15°C to about 15°C, preferably about 0°C,
`
`for a time period between about 20 minutes to about 50 minutes, preferably about 35
`
`-minutes. Upon completion of the reaction, the mixture is diluted with water and
`
`extracted with ethyl acetate. The combined organics are then washed with saturated
`
`sodium bicarbonate followed by sodium sulfite. The compound so formed in a polar
`
`aprotic solvent, preferably tetrahydrofuran, is treated with sodium hydride, heated to
`
`reflux and stirred for a time period between about 30 minutes to about 60 minutes,
`
`preferably 45 minutes. The reaction mixture is cooled to a temperature between about
`
`20°C to about 30°C, preferably about 25°C, and an alkyl halide of formula R2 halide,
`
`wherein R2 is as defined with reference to formula I other than a group of formula II, is
`
`added. The reaction mixture is stirred and heated to reflux for a time period between
`
`about 12 hours to about 20 hours, preferably 16 hours.
`
`In Reaction _2_ of Scheme 2,
`
`the 2-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-
`
`c]pyridine compound IX is converted to the corresponding compound of formula X by
`
`reacting lX with a reducing agent, preferably lithium aluminum hydride, in a non-polar
`
`aprotic solvent, preferably ether. The reaction is stirred for a time period between about
`
`12 hours to about 20 hours, preferably 16 hours. Water and base, preferably sodium
`
`hydroxide, is then added and the reaction mixture is stirred for a time period between
`
`

`
`WO 95/01980
`
`PCT/IB94/00156
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`-10-
`
`about 1.5 hours to about 2.5 hours, preferably 2 hours, and filtered. The filtrate is
`
`concentrated to a white solid.
`
`The ability of the compounds or the pharmaceutically acceptable salts thereof
`
`to inhibit phosphodiesterase lV (PDE4) and, consequently, demonstrate their
`
`effectiveness for treating inflammatory diseases is shown by the following i_n_ v_it_r_o_ assay.
`
`BIOLOGICAL ASSAY
`
`(Human lung PDE,(,)
`
`Thirty to forty grams of human lung tissue is placed in 50 ml of pH 7.4
`
`Tris/phenylmethylsulfonyl fluoride (PMSF)/sucrose buffer and homogenized using a
`
`Tekmar Tissumizer® (Tekmar Co., 7143 Kemper Fioad, Cincinnati, Ohio 45249) at full
`
`speed for 30 seconds. The homogenate is centrifuged at 48,000 x g for 70 minutes at
`
`4°C. The supernatant is filtered twice through a 0.22 /.ll’Tl filter and applied to a Mono-Q
`
`FPLC column (Pharmacia LKB Biotechnology, 800 Centennial Avenue, Piscataway, New
`
`Jersey 08854) pre-equilibrated with pH 7.4 Tris/PMSF buffer. A flow rate of 1 ml/minute
`
`is used to apply the sample to the column, followed by a 2 ml/minute flow rate for
`
`subsequent washing and elution. Sample is eluted using an increasing, step-wise NaC|
`
`gradient in the pH 7.4 Tris/PMSF buffer. Eight ml fractions are collected. Fractions are
`
`assayed for specific PDEW activity, determined by [3H]cAMP hydrolysis and the ability
`
`of a known PDEW inhibitor (e.g. rolipram) to inhibit that hydrolysis. Appropriate
`
`fractions are pooled, diluted with ethylene glycol (2 ml ethylene glycol/5 ml of enzyme
`
`prep) and stored at —20°C until use.
`
`Compounds are dissolved in DMSO at a concentration of 10 mM and diluted
`
`1:25 in water (400 ,uM compound, 4% DMSO). Further serial dilutions are made in 4%
`
`DMSO to achieve desired concentrations. Final DMSO concentration in assay tube is
`1%.
`In duplicate the following are added, in order, to a 12 x 75 mm glass tube (all
`
`concentrations are given as final concentrations in assay tube).
`
`‘
`
`i)
`
`ii)
`
`iii)
`
`iv)
`
`25 pl compound or DMSO (1%, for control and blank)
`
`25 pl pH 7.5 Tris buffer
`
`[3HicAMP (1 ,uM)
`
`25 ,ul ’F’DE,V enzyme (for blank, enzyme is preincubated in boiling water
`
`for 5 minutes)
`
`The reaction tubes are shaken and placed in a water bath (37°C) for 20
`
`minutes, at which time the reaction is stopped by placing the tubes in a boiling water
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`

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`WO 95/01980
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`PCT/IB94/00156
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`.1].
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`bath for 4 minutes. Washing buffer (0.5 ml, 0.1M 4-(2-hydroxyethyl)-1-piperazine-
`
`ethanesulfonic acid (HEPES)/0.1 M NaCl, pH 8.5) is added to each tube on an ice bath.
`
`The contents of each tube are applied to an Affi-Gel 601 column (Biorad Laboratories,
`
`P.O. Box 1229, 85A Marcus Drive, Melville, New York 11747) (boronate affinity gel, 1
`
`ml bed volume) previously equilibrated with washing buffer.
`
`[3H]cAMP is washed with
`
`2 x 6 ml washing buffer, and [3H]5'AMP is then eluted with 4 ml of 0.25M acetic acid.
`
`After vortexing, 1 ml of the elution is added to 3 ml scintillation fluid in a suitable vial,
`
`vortexed and counted for [3H].
`
`% inhibition = 1
`
`- average cpm (test compound) - average cpm (blank)
`average cpm (control) - average cpm (blank)
`
`ICED is defined as that concentration of compound which inhibits 50% of specific
`
`hydrolysis of [3H]cAMP to [3H]5'AMP.
`
`(TNF)
`
`The ability of the compounds or the pharmaceutically acceptable salts thereof
`
`to inhibit the production of TNF and, consequently, demonstrate their effectiveness for
`
`treating diseases involving the production of TNF is shown by the following i_r_i
`
`\_/it_rq
`
`assay:
`
`Peripheral
`
`blood
`
`(100 mls)
`
`from human volunteers
`
`is
`
`collected in
`
`ethylenediaminetetraacetic acid (EDTA).’ Mononuclear
`
`cells
`
`are
`
`isolated by
`
`Ficoll/Hypaque and washed three times in incomplete HBSS. Cells are resuspended
`
`in afinal concentration of 1 x 105 cells per ml in pre—warmed FlPMl (containing 5% FCS,
`
`glutamine, pen/step and nystatin). Monocytes are plated as 1 x 105 cells in 1.0 ml in
`
`24-well plates. The cells are incubated at 37°C (5% carbon dioxide) and allowed to
`
`adhere to the plates for 2 hours, after which time non-adherent cells are removed by
`
`gentle washing.
`
`Test compounds ‘(10)ul) are then added to the cells at 3-4
`
`concentrations each and incubated for 1 hour. LPS (1 Opl)
`
`is added to appropriate
`
`wells; Plates are incubated overnight (18 hrs) at 37°C. At the end of the incubation
`
`period TNF was analyzed by a sandwich ELISA (Fl&D Quantikine Kit).
`
`ICSO
`
`determinations are made for each compound based on linear regression analysis.
`
`Pharmaceutically-acceptable acid addition salts of the compounds of this
`
`invention include, but are not limited to, those formed with HCl, HBr, HNO3, H2804,
`
`H3PO,,, CH3SO3H, p-CH3C6H4SO3H, CH3CO2H, gluconic acid, tartaric acid, maleic acid
`
`and succinic acid. Pharmaceutically-acceptable cationic salts of the compounds of this
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`

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`WO 95/01980
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`PCT/IB94/00156
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`-12-
`
`invention of formula I wherein R4 is CO2R6 and H6 is hydrogen include, but are not
`
`limited to,
`
`those of sodium, potassium, calcium, magnesium, ammonium, N,N'-
`
`dibenzylethylenediamine, N-methylglucamine
`
`(meglumine),
`
`ethanolamine
`
`and
`
`diethanolamine.
`
`For administration to humans in the curative or prophylactic treatment of
`
`inflammatory diseases, oral dosages of
`
`the compounds of formula I and the
`
`pharmaceutically acceptable salts thereof (hereinafter also referred to as the active
`
`compounds of the present invention) are generally in the range of from 0.1-100 mg
`
`daily for an average adult patient (70 kg). Thus for a typical adult patient, individual
`
`tablets or capsules contain from 0.1 to 50mg of active compound,
`
`in a suitable
`
`pharmaceutically acceptable vehicle or carrier. Dosages for intravenous administration
`
`are typically within the range of 0.1 to 10 mg per single dose as required.
`
`For
`
`intranasal or inhaler administration, the dosage is generally formulated as a 0.1 to 1%
`
`(w/v) solution.
`
`In practice the physician will determine the actual dosage which will be
`
`most suitable for an individual patient and it will vary with the age, weight and response
`of the particular patient. The above dosages are exemplary of the average case but
`
`there can, of course, be individual instances where higher or lower dosage ranges are
`
`merited, and all such dosages are within the scope of this invention.
`
`For administration to humans for the inhibition of TNF, a variety of conventional
`
`routes may be used including orally, parenterally and topically.
`
`In general, the active
`
`compound will be administered orally or parenterally at dosages between about 0.1 and
`
`25 mg/kg body weight of the subject to be treated per day, preferably from about 0.3
`
`to 5 mg/kg. However, some variation in dosage will necessarily occur depending on
`
`the condition of the subject being treated. The person responsible for administration
`
`will, in any event, determine the appropriate dose for the individual subject.
`
`For human use, the active compounds of the present
`
`invention can be
`
`administered alone, but will generally be administered in an admixture with a
`
`pharmaceutical diluent or carrier selected with regard to the intended route of
`
`administration and standard pharmaceutical practice.
`
`For example, they may be
`
`administered orally in the form of tablets containing such excipients as starch or
`
`lactose, or in capsules or ovales either alone or in admixture with excipients, or in the
`
`form of elixirs or suspensions containing flavoring or coloring agents. They may be
`
`injected parenterally; for example, intravenously, intramuscularly or subcutaneously.
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`

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`WO 95/01980
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`PCT/IB94/00156
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`-13-
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`For parenteral administration, they are best used in the form of a sterile aqueous
`
`solution which may contain other substances; for example, enough salts or glucose to
`
`make the solution isotonic.
`
`Thus in a further aspect the invention provides pharmaceutical compositions
`
`comprising a compound of the formula I and the pharmaceutically acceptable salts
`
`thereof together with a pharmaceutically acceptable diluent or carrier.
`
`The present invention is illustrated by the following examples, but it is not limited
`
`to the details thereof.
`
`3-Eth |-1—4—methox
`
`hen |-6- hen I-7~oxo-45 6 7-tetrah dro-1 H-
`
`Example 1
`
`clpyridine
`
`A mixture of 3—hydroxy-2-oxo—1-phenyl—4-propionyl-1,2,5,6-tetrahydro-pyridine (1.0
`
`g, 4.1 mmole), 4-methoxyphenylhydrazine hydrochloride (0.8 g, 4.6 mmole) and sodium
`
`methoxide (0.11 grams, 2 mmole) in 35 ml anhydrous ethanol (distilled from Mg) was
`heated at reflux. After 12 hours, the solvent was removed by rotory evaporation under
`
`reduced pressure, and the crude residue was chromatographed on a 4x20 cm silica
`
`column using 1:1 ether/hexane as eluent to give 345 mg of the title compound as a red
`
`oil
`
`that crystallized upon standing at
`
`room temperature.
`
`The desired 1-(4-
`
`methoxyphenyl) regiolsomer is less polar than the 2-(4-methoxyphenyl) byproduct.
`
`M.P. 43-45°C, IR (chloroform) lactam C=O, 1665 cm"; ‘H NMR (300 MHz, CDCI3) d
`
`1.32 (t,J = 7.6 Hz, 3H), 2.74 (q, J = 7.6 Hz, 2H), 2.96 (t, J = 6.6 Hz, 2H), 3.79 (s, 3H),
`
`4.10 (t,J = 6.6 Hz, 2H), 6.89 (d,J = 9.0 Hz, 2H), 7.22-7.39 (m, 5H), 7.45 (d,J = 9.0 Hz,
`
`2H); Anal. calcd. for C2,H2,N3O2: C, 72.60; H, 6.09; N, 12.09. Found: C, 72.48; H,
`6.08; N, 11.66; MS m/z (M*) 347.
`
`A
`
`Examples 2-15
`
`Reaction of the appropriate hydrazine hydrochloride with the requisite 4-
`
`alkanoyl-3-hydroxy-2-oxo-1,2,5,6-tetrahydropyridine, analogous to the procedure of
`
`Example 1, affords the following compounds.
`
`Ex.# R‘
`
`_ phenyl
`ethyl
`phenyl
`
`tert-butyl
`
`M.p.°C Mass Spectra or Mass Spectra or
`Analysis (calcd.)
`Analysis (found)
`%C. %H, %N
`%C, %H, %N
`70.56, 6.71, 16.46
`70.61, 6.77, 15.51
`72.70, 7.79, 14.13
`72.50, 7.96, 14.16
`
`80-83
`120-121
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`

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`WO 95/01980
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`PCT/IB94/00156
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`ethyl
`
`ethyl
`
`4—methoxy 4—methoxy 42-45
`phenyl
`phenyl
`
`70.01,6.14, 11.13 70.05, 6.07, 11.00
`
`4-fluoro
`phenyl
`
`tert-butyl
`
`(M *) 315.1747
`
`HRMS (M+)
`315.1741
`
`ethyl
`
`phenyl
`
`3,4-
`dichloro-
`
`phenyl
`
`(oil)
`
`[M*] 386.25
`
`MS m/z [M+] 386
`
`ethyl
`
`4—fluoro
`phenyl
`
`4-methoxy 129-130' 69.03, 5.52, 11.50 68.75, 5.37, 11.43
`phenyl
`
`139-140”
`
`[M’] 321.3
`
`MS m/z [M*] 322
`
`HRMS (M+)
`309.1823
`
`HRMS (M+)
`333.1477
`
`HRMS (M+)
`388.2395
`
`methyl
`
`phenyl
`
`ethyl
`
`phenyl
`
`4 fluoro
`phenyl
`
`cyclopent
`yl
`
`73-75
`
`(M+) 309.1841
`
`10
`
`methyl
`
`phenyl
`
`4—methoxy 167-168
`phenyl
`
`(M+) 333.1477
`
`11
`
`ethyl
`
`phenyl
`
`5-phenyl
`pentyl
`
`(oil)
`
`(M+ 388.2389
`
`methyl
`
`4—methoxy 4-fluoro
`phenyl
`phenyl
`
`methyl
`
`4—methoxy 3—f|uoro
`phenyl
`phenyl
`
`140-142" 68.36, 5.16, 11.96 67.92, 5.03, 11.72
`
`133-138
`
`68.36, 5.16, 11.96 68.04, 5.04, 11.75
`
`ethyl
`
`4—methoxy 3,4-
`
`60.59, 4.60, 10.09 60.34, 4.56, 9.86
`
`ethyl
`
`3-methoxy methyl
`phenyl
`
`(oil)
`
`[M*] 285.35
`
`MS m/z [M*] 286
`
`4
`
`5
`
`Recrystallizing solvents: “isopropyl ether. ”5% Ethyl acetate in petroleum ether.
`
`Example 16
`
`' 3-Eth l-1- 4- hen lcarbox lic
`
`acid -6- hen l-7-oxo-4 5 67-tetrah dro-1H-
`
`pyrazolo]3,4—c|pyridine
`
`1 A mixture of 3-hydroxy-2-oxo-1-phenyl-4-propionyl-1,2,5,6-tetrahydro-pyridine (1.0
`
`grams, 4.08 mmole), 4-hydrazinobenzoic acid (0.68 grams, 4.49 mmole) and 30 ml of
`
`anhydrous ethanol was heated at reflux. After 20 hours, the mixture was concentrated
`
`by rotory evaporation under reduced pressure, and the solid residue was suspended
`
`in a mixture of ethyl acetate (500 ml) and pH 4 buffer (200 ml). The organic layer was
`
`separated (leaving behind most of the 2-(4-phenylcarboxylic acid) byproduct), washed
`
`with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure.
`
`

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`WO 95/01980
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`PCT/IB94/00156
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`-15-
`
`Recrystallization from methanol gives 0.64 grams of the title compound as an orange
`
`solid. M.P. 261-263°C, ‘H_ NMR (300 MHz, DMSO-gs) d 1.23 (t,.l = 7.6 Hz, 3H), 2.68
`
`(q,J - 7.6 Hz, 2H), 2.94 (t,J = 6.5 Hz, 2H), 4.05 (t,J = 6.5 Hz, 2H), 7.20-7.41 (m, 5H),
`
`7.65 (d,J = 8.6 Hz, 2H), 7.96 (d,J = 8.6 Hz, 2H), 13.05 (s, 1H); MS m/z (M*) 362.
`
`1- 4-Benzamide -3-eth l~6- 4-methox
`
`hen I -7-oxo-4 5 6 7-tetrah dro-1H-
`
`Example 17
`
`pyrazolo|3,4-c|pyridine
`
`To a stirred solution of sodium methoxide in methanol (prepared from 6.6 mg
`
`Na)
`
`is added 3-ethy|-6-(4-methoxyphenyl)-1-(4-phenylcarboxylic acid)-7-oxo-4,5,6,7-
`
`tetrahydro-1H-pyrazoIo[3,4-o]pyridine (96 mg, 0.25 mmole). After 30 minutes, methanol
`
`was removed under reduced pressure, the solid residue was suspended in benzene,
`
`and the benzene was removed under reduced pressure. The resulti