PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(51) International Patent Classification 6 :
`
`(11) International Publication Number:
`
`W0 97/03675
`
`A61K 31/495
`
`(43) International Publication Date:
`
`6 February 1997 (06.02.97)
`
`(21) International Application Number:
`
`(22) International Filing Date:
`
`11 July 1996 (11.07.96)
`
`(30) Priority Data:
`95144648
`
`14 July 1995 (14.07.95)
`
`GB
`
`(71) Applicant (for all designated States except US): LABORA-
`TOIRE GLAXO WELLCOME S.A.
`[FR/FR]; 43,
`rue
`Vineuse, F-75116 Paris (FR).
`
`(72) Inventor; and
`(75) Inventor/Applicant (for US only): DAUGAN, Alain, Claude-
`Marie [FR/FR]; Laboratoire Glaxo Wellcome S.A., Centre
`de Recherches, Z.A. dc Courtaboeuf, 25, avenue de Quebec,
`F—91940 Les Ulis (FR).
`
`(74) Agents: FILLER, Wendy, Anne et a1.; Glaxo Wellcome House,
`Berkeley Avenue, Greenford, Middlesex UB6 ONN (GB).
`
`MD, MG, MK, MN,
`SD, SE, SG, SI, SK,
`VN, ARIPO patent (KE, LS, MW, SD, 32, UG), Eurasian
`patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
`patent (AT, BE, CH, DE
`, FR, GB, GR, IE, IT,
`LU, MC, NL, PT, SE),
`te t (BF, BI, CF, CG, CI,
`CM, GA, GN, ML, MR, NE, S , TD, TG).
`
`Published
`With international search report.
`
`
`
`(54) Title: USE OF CGMP—PHOSPHODIESTERASE INHIBITORS TO TREAT IMPOTENCE
`
`(57) Abstract
`
`The
`
`(1)
`formula
`of
`compounds
`of
`use
`123R)-2,3,6,7,12,12a-hexahydro-2-methyl-
`(6R,
`6-(3,4—methylenedioxypbenyl)-pyrazino[2’ ,1 ’:
`6,1]pyrido[3,4-b]indole-l,4—dione,
`(SS,
`12aR)—2,3,6,7, 12,12a-hexahydro-2,3-dimethy1-
`6-(3,4-methylenedioxyphenyl)-pyrazino[2’,1 ’:
`6,1]pyrido[3,4»b]indole-1,4-dione, and physiologically
`acceptable salts and solvates thereof,
`in the treatment
`of impotence.
`
`6R,
`
`ATI 1005 -0001
`
`ATI V. ICOS
`
`IPR2018-01183
`
`ATI 1005-0001
`
`ATI v. ICOS
`IPR2018-01183
`
`

`

`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 PCT.
`
`Viet Nam
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungaw
`Ireland
`Italy
`Japan
`Kenya
`Kyrgystan
`Democratic People’s Republic
`of Korea
`Republic of Korea
`Kankhstan
`Liechtenstein
`Sri Lanka
`Liberia
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`Mauritania
`
`AM
`AT
`AU
`BB
`BE
`BF
`BG
`BJ
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`CS
`CZ
`DE
`DK
`EE
`ES
`FI
`FR
`GA
`
`Armenia
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Céte d'Ivoire
`Cameroon
`China
`Czechoslovakia
`Czech Republic
`Germany
`Denmark
`Estonia
`Spain
`Finland
`France
`Gabon
`
`ATI 1005-0002
`
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`
`ATI 1005-0002
`
`

`

`WO 97/03675
`
`'
`
`PCT/EP96/03024
`
`USE OF CGMP-PHOSPHODIESTERASE INHIBITORS T0 TREAT IMPOTENCE
`
`This invention relates to the use of tetracyclic derivatives which are potent
`and selective inhibitors of cyclic guanosine 3',5'—monophosphate specific
`phosphodiesterase (cGMP specific PDE) in the treatment of impotence.
`
`Impotence can be defined as a lack of power, in the male, to copulate and
`may involve an inability to achieve penile erection or ejaculation, or both. More
`specifically, erectile impotence or dysfunction may be defined as an inability to
`obtain or sustain an erection adequate for intercourse.
`Its prevalence is claimed
`to be between 2 and 7% of the human male population, increasing with age, up
`to 50 years, and between 18 and 75% between 55 and 80 years of age.
`
`Reports of well-controlled clinical trials in man are few and the efficacy of
`orally administered drugs is low. Although many different drugs have been
`shown to induce penile erection, they are only effective after direct injection into
`the penis, e.g. intraurethrally or intracavemosally (i.c.), and are not approved for
`erectile dysfunction. Current medical treatment is based on the i.c. injection of
`vasoactive
`substances
`and
`good
`results
`have
`been
`claimed with
`phenoxybenzamine, phentolamine, papaverine and prostaglandin E1, either
`alone or in combination; however, pain, priapism and fibrosis of the penis are
`associated with the i.c. administration of some of these agents. Potassium
`channel openers (K00) and vasoactive intestinal polypeptide (VIP) have also
`been shown to be active i.c., but cost and stability issues could limit
`development of the latter. An alternative to the i.c. route is the use of glyceryl
`trinitrate (GTN) patches applied to the penis, which has been shown to be
`effective but produces side-effects in both patient and partner.
`
`As a general alternative to pharmacological intervention, a variety of penile
`prostheses has been used to assist achievement of an erection. The short term
`success rate is good, but problems with infection and ischaemia. especially in
`diabetic men, make this type of treatment a final option rather than first-line
`
`10
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`30
`
`therapy.
`
`The compounds of the invention are potent inhibitors of cyclic guanosine 3',5‘-
`monophosphate phosphodiesterases (cGMP PDEs). GB 9514464.8, which is
`the priority document for the present application describes the syntheses of the
`compounds of the invention and their utility in impotence. W095/19978, which
`
`ATI 1005-0003
`
`ATI 1005-0003
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`was unpublished at the priority date of the present application, also describes
`
`the syntheses of the compounds of the invention and their utility in other
`
`diseases associated with inhibition of cGMP PDEs. The compounds may be
`
`represented by the following general formula (I):
`
`(I)
`
`and salts andsolvates (e.g. hydrates) thereof, in which:
`
`10
`
`'
`‘ R0 represents hydrogen, halogen or 01-5 alkyl;
`R1 represents hydrogen, C1_3alkyl, C26 alkenyl, 02.5 alkynyl, haloC1-5alkyl,
`
`C3_gcycloalkyl, 03-8cycloalkle1-3alkyl, arle1_3alkyl or heteroarle1_3alkyl;
`R2 represents an optionally substituted monocyclic aromatic ring selected
`
`from benzene, thiophene, furan and pyridine or an optionally substituted bicyclic
`
`03>
`
`ring
`
`attached to the rest of the molecule via one of the benzene
`
`15
`
`20
`
`25
`
`ring carbon atoms and wherein the fused ring A is a 5- or 6-membered ring
`
`which may be saturated or partially or fully unsaturated and comprises carbon
`atoms and optionally one or two heteroatoms selected from oxygen, sulphur and
`
`nitrogen; and
`
`R3 represents hydrogen or C1_3 alkyl, or R1 and R3 together represent a 3- or
`4- membered alkyl or alkenyl chain.
`
`Suitable individual compounds of the invention for use in the treatment of
`
`erectile dysfunction include:
`Cis-2,3,6,7,12,12a-hexahydro-2-(4-pyridylmethyl)-6-(3,4—methylenedioxyphenyl)-
`
`pyrazino[2', 1'
`
`: 6,1]pyrido[3,4-b]indole-1,4-dione;
`
`Cis-2,3,6,7,12,12a-hexahydro—6-(2,3-dihydrobenzo[b]furan-5-yl)-2-methyl-
`
`pyrazino[2',1'26,1]pyrido[3,4—b]indole -1,4—dione;
`
`Cis-2,3,6,7,12,12a-hexahydro-6-(5-bromo—2-thienyl)-2-methyl-
`
`pyrazino[2',1“:6,1]pyrido[3,4-b]indole -1,4-dione;
`
`ATI 1005-0004
`
`ATI 1005-0004
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`Cis-2,3,6,7,12,12a-hexahydro-2-butyl-6-(4-methylphenyl)-
`
`pyrazino[2',1':6,1]pyrido[3,4-b]indole -1,4-dione;
`
`(6R,12aR)—2,3,6,7,12,12a-Hexahydro-2-isopropyl-6—(3,4-methylenedioxyphenyl)-
`
`pyrazino[2',1':6,1]pyrido[3,4-b]indole -1,4-dione;
`
`(6R,12aR)-2,3,6,7,12,12a—Hexahydro-2-cyclopentyl—6-(3,4—
`
`methylenedioxyphenyl)-pyrazino[2',1':6,1]pyrido[3,4—b]indole -1,4-dione;
`
`(6R,12aR)—2,3,6,7,12,12a-Hexahydro-2-cyclopropylmethyl-6-(4-methoxyphenyl)—
`
`pyrazino[2',1':6,1]pyrido[3,4—b]indole -1,4-dione;
`
`(6R,12aR)-2,3,6,7,12,12a-Hexahydro-6-(3-chIoro-4-methoxyphenyl)-2-methyl-
`
`pyrazino[2',1'16,1]pyrido[3,4-b]indole -1,4-dione;
`
`(6R,12aR)—2,3,6,7,12,12a—Hexahydro-2-methyl—6-(3,4-methylenedioxyphenyl)-
`pyrazino[2',1'16,1]pyrido[3,4-b]indole-1,4-dione;
`
`(6R, 12aR)—2,3,6,7,12,12a-Hexahydro-6-(3,4-methylenedioxyphenyl)-
`
`pyrazino[2', 1'
`
`: 6,1] pyrido [3,4—b] indoIe-1,4-dione;
`
`(5aR, 12R, 14aS)-1,2,3,5,6,11,12,14a-Octahydro—12—(3,4—
`
`methylenedioxyphenyI)-pyrrolo[1",2" : 4',5']pyrazino[2',1' : 6,1]pyrido[3,4—
`
`b]indole-5-1 ,4-dione;
`Cis-2,3,6,7,12,12a-hexahydro-2-cyclopropyI-6-(3,4-methylenedioxyphenyl)-
`
`pyrazino[2',1'16,1]pyrido[3,4-b]indole -1,4-dione;
`
`(3S, 6R,12aR)—2,3.6,7,12,12a-hexahydro-3-methyI-6-(3,4-
`
`methylenedioxyphenyl)-pyrazino[2',1'26,1]pyrido[3,4-b]indole -1,4-dione;
`
`and physiologically acceptable salts and solvates (e.g. hydrates) thereof.
`
`The specific compounds of the invention are:
`
`10
`
`15
`
`20
`
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`
`(6R,12aR)—2,3,6,7,12,12a-hexahydro-2-methyl-6—(3,4-methylenedioxyphenyl)-
`pyrazino[2‘,1'26,1]pyrido[3,4-b]indole —1,4-dione (Compound A); and
`
`(38, ER, 12aR)~2,3,6,7,12,12a-hexahydro-2,3-dimethyl-6-(3,4-
`methylenedioxyphenyl)—pyrazino[2',1'
`: 6,1]pyrido[3,4-b]indole-1,4~dione
`
`(Compound B);
`
`and physiologically acceptable salts and solvates (e.g. hydrates) thereof.
`
`30
`
`Unexpectedly, it has now been found that compounds of formula (I), and in
`particular compounds A and B, are useful
`in the treatment of erectile
`
`dysfunction. Furthermore the compounds may be administered orally, thereby
`
`ATI 1005-0005
`
`ATI 1005-0005
`
`

`

`. WO 97/03675
`
`PCT/EP96/03024
`
`4
`
`obviating the disadvantages associated with i.c. administration.
`Thus the
`present
`invention concerns the use of compounds of formula (I), and in
`particular compounds A and B, or a pharmaceutically acceptable salt thereof, or
`a pharmaceutical composition containing either entity, for the manufacture of a
`
`medicament for the curative or prophylactic treatment of erectile dysfunction in a
`male animal, including man.
`
`The pharmaceutically acceptable salts of the compounds of formula (I), and in
`particular compounds A and B which contain a basic centre are acid addition
`
`salts formed with pharrnaceutically acceptable acids. Examples include the
`hydrochloride, hydrobromide, sulphate or bisulphate, phosphate or hydrogen
`phosphate, acetate, benzoate, succinate, fumarate, maleate,
`lactate, citrate,
`tartrate,
`gluconate,
`methanesulphonate,
`benzenesulphonate
`and
`p-toluenesulphonate salts. Compounds of
`formula
`(I),
`and in particular
`compounds A and B can also provide phannaceutically acceptable metal salts,
`in particular alkali metal salts, with bases. Examples include the sodium and
`potassium salts.
`
`It has been shown that compounds of the present invention are potent and
`selective inhibitors of cGMP specific PDE.
`It has now been surprisingly found
`that human corpus cavemosum contains three distinct PDE enzymes. The
`predominant PDE has further surprisingly been found to be cGMP PDE. As a
`consequence of the selective PDE V inhibition exhibited by compounds of the
`present invention, the subject compounds can elevate cGMP levels. which in
`turn can mediate relaxation of the corpus cavemosum tissue and consequent
`penile erection.
`
`Although the compounds of the invention are envisaged primarily for the
`treatment of erectile dysfunction or male sexual dysfunction, they may also be
`useful
`for
`the treatment of female sexual dysfunction including orgasmic
`dysfunction related to clitoral disturbances.
`
`in man, oral administration of the compounds of the invention is
`Generally,
`the preferred route, being the most convenient and avoiding the disadvantages
`associated with i.c. administration.
`In circumstances where the recipient suffers
`from a swallowing disorder or from impairment of drug absorption after oral
`administration, the drug may be administered parenterally, e.g. sublingually or
`buccally.
`
`10
`
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`
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`
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`
`30
`
`ATI 1005-0006
`
`ATI 1005-0006
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`For administration to man in the curative or prophylactic treatment of the
`disorders identified above, oral dosages of a compound of formula (I), and in
`particular compounds A and B will generally be in the range of from 0.5-800mg
`daily for an average adult patient (70kg). Thus for a typical adult patient,
`individual tablets or capsules contain from 0.2-400mg of active compound, in a
`suitable pharmaceutically acceptable vehicle or carrier, for administration in
`
`single or multiple doses, once or several times per day. Dosages for buccal or
`sublingual administration will typically be within the range of from 0.1-400 mg
`per single dose as required.
`In practice the physician will determine the actual
`dosing regimen 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 be individual
`instances in which higher or lower dosage ranges may be merited, and such are
`within the scope of this invention.
`
`For human use, compounds of formula (I), and in particular compounds A and
`B can be administered alone, but will generally be administered in admixture
`with a pharmaceutical carrier selected with regard to the intended route of
`administration and standard pharmaceutical
`practice.
`For example,
`the
`compound may be administered orally, buccally or sublingually,
`in the form of
`tablets containing excipients such as starch or lactose, or in capsules or ovules
`either alone or
`in admixture with excipients, or in the form of elixirs or
`
`suspensions containing flavouring or colouring agents. Such liquid preparations
`may be prepared with pharmaceutically acceptable additives
`such as
`suspending agents (eg. methylcellulose, a semi-synthetic glyceride such as
`witepsol or mixtures of glycerides such as a mixture of apricot kernel oil and
`PEG-6 esters or mixtures of PEG-8 and caprylic/capric glycerides).
`
`For veterinary use, a compound of formula (I), and in particular compound A
`or B or a non—toxic salt thereof is administered as a suitably acceptable
`formulation in accordance with normal veterinary practice and the veterinary
`surgeon will determine the dosing regimen and route of administration which will
`be most appropriate for a particular male animal.
`
`Thus the invention includes a pharmaceutical composition for the curative or
`prophylactic treatment of erectile dysfunction in a male animal, including man,
`comprising a compound of formula (I), and in particular compound A or B, or a
`pharmaceutically acceptable salt
`thereof,
`together with a pharmaceutically
`acceptable diluent or carrier.
`
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`
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`35
`
`ATI 1005-0007
`
`ATI 1005-0007
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`6
`
`There is further provided a process for the preparation of a pharmaceutical
`composition for the curative or prophylactic treatment of erectile dysfunction in a
`male animal, including man, comprising formulating a compound of formula (I),
`and in particular compound A or B, or a pharmaceutically acceptable salt
`thereof, with a pharmaceutically acceptable diluent or carrier.
`
`including
`The invention also provides a method of treating a male animal,
`man, to cure or prevent erectile dysfunction which comprises treating said male
`animal with an effective amount of a compound of formula (I), and in particular
`compound A or B, or a pharmaceutically acceptable salt
`thereof, or a
`pharmaceutical composition containing either entity.
`
`Moreover, the invention includes the use of a compound of formula (l), and in
`particular compound A or B, or a pharmaceutically acceptable salt thereof, or a
`pharmaceutical composition containing either entity, for the manufacture of a
`medicament for the curative or prophylactic treatment of erectile dysfunction in a
`male animal, including man.
`
`A compound of formula (I), and in particular compound A or B, may also be
`used in combination with other therapeutic agents which may be useful in the
`treatment of erectile dysfunction substantially as hereinbefore described. The
`invention thus provides,
`in another aspect, a combination of a compound of
`formula (I), and in particular compound A or B together with another
`therapeutically active agent.
`
`The combination referred to above may conveniently be presented for use in
`the form of a pharmaceutical formulation and thus pharmaceutical compositions
`comprising a combination as defined above together with a pharmaceutically
`acceptable diluent or carrier comprise a further aspect of the invention.
`
`The individual components of such a combination may also be administered
`either sequentially or simultaneously in separate pharmaceutical formulations.
`
`Appropriate doses of known therapeutic agents for use in combination with a
`compound of the invention will be readily appreciated by those skilled in the art.
`
`The compounds of the invention may be prepared by any suitable method
`known in the art or by the following process which forms part of the present
`invention. The process has been previously substantially described in the
`priority document of the present invention G89514464.8, and in W095/19978.
`
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`ATI 1005-0008
`
`ATI 1005-0008
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`Thus, a process for preparing a compound of formula (I) comprises treating a
`compound of formula (ll)
`
`0
`
`OAlk
`
`I
`
`NH
`
`(II)
`
`R°
`
`is a halogen
`(in which Alk represents C1-5alkyl, e.g. methyl or ethyl and Hal
`atom, e.g. chlorine) with a primary amine R1NH2 in a suitable solvent such as
`an alcohol (e.g. methanol or ethanol) or a mixture of solvents, conveniently at a
`temperature of from 20°C to reflux (e.g. at about 50°C).
`
`A compound of formula (II) may conveniently be prepared by treating a
`compound of formula (III) with a compound of formula (IV)
`
`Re
`
`0
`
`NH
`
`OAlk
`
`R2
`
`(III)
`
`I
`
`IZ
`
`0
`
`H I
`Halkr a3
`
`(IV)
`
`R
`
`in a suitable solvent such as a halogenated hydrocarbon (e.g. trichloromethane
`or dichloromethane), or an ether (e.g.
`tetrahydrofuran), preferably in the
`presence of a base such as an organic amine (e.g. a trialkylamine such as
`triethylamine) or an alkali metal carbonate or bicarbonate (e.g. NaHCOg). The
`reaction may conveniently be effected at a temperature of from -20°C to +20°C
`(e.g. at about 0°C).
`
`A compound of formula (I) may also be prepared from a compound of formula
`(Ill)
`in a two-step procedure via a compound of formula (II) isolated without
`punficafion.
`
`Compounds of formula (I) may be prepared as individual enantiomers in two
`steps from the appropriate enantiomer of formula (III) or as mixtures (e.g.
`racemates) of either pairs of cis or trans isomers from the correspondong
`mixtures of either pairs of cis or trans isomers of formula (III).
`
`1O
`
`15
`
`20
`
`ATI 1005-0009
`
`ATI 1005-0009
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`Individual enantiomers of the compounds of the invention may be prepared
`from racemates by resolution using methods known in the art for the separation
`of racemic mixtures into their constituent enantiomers, for example using HPLC
`(high performance liquid chromatography) on a chiral column such as Hypersil
`naphthylurea.
`
`A compound of formula (III) may conveniently be prepared from a tryptophan
`alkyl ester of formula (V)
`
`R°
`
`o
`
`NH2
`
`OAlk
`
`(V)
`
`l
`
`N
`
`10
`
`15
`
`20
`
`25
`
`30
`
`(where Alk is as previously defined) or a salt thereof (e.g. the hydrochloride salt)
`with an aldehyde RZCHO. The reaction may conveniently be effected in a
`suitable solvent such as a halogenated hydrocarbon (e.g. dichloromethane) or
`an aromatic hydrocarbon (e.g. toluene) in the presence of an acid such as
`trifluoroacetic acid.
`The reaction may conveniently be carried out at a
`temperature of from -20°C to reflux to provide a compound of formula (III) in one
`step. The reaction may also be carried out in a solvent such as an aromatic
`hydrocarbon (e.g. benzene or toluene) under reflux, optionally using a Dean-
`Stark apparatus to trap the water produced.
`
`The reaction provides a mixture of cis and trans isomers which may be either
`individual enantiomers or racemates of pairs of cis or trans isomers depending
`upon whether racemic or enantiomerically pure tryptophan alkyl ester was used
`as the starting material.
`Individual cis or trans enantiomers may conveniently be
`separated
`from mixtures
`thereof
`by
`fractional
`crystallisation
`or
`by
`chromatography (e.g. flash column chromatography) using appropriate solvents
`and eluents.
`Similarly, pairs of cis and'trans isomers may be separated by
`chromatography (e.g. flash column chromatography) using appropriate eluents.
`An optically pure trans isomer may also be converted to an optically pure cis
`isomer using suitable epimerisation procedures. One such procedure comprises
`treating the trans isomer or a mixture (e.g. 1 : 1 mixture) of cis and trans isomers
`with methanolic or aqueous hydrogen chloride at a temperature of from 0°C to
`the refluxing temperature of the solution. The mixture may then be subjected to
`chromatography (e.g. flash column chromatography) to separate the resulting
`diastereoisomers, or in the procedure utilising aqueous hydrogen chloride the
`
`ATI 1005-0010
`
`ATI 1005-0010
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`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`desired cis isomer precipitates out as the hydrochloride salt which may then be
`isolated by filtration.
`
`The pharmaceutically acceptable acid addition salts of a compound of
`formula (I). and in particular compound A or B which contain a basic centre may
`be prepared in a conventional manner. For example, a solution of the free base
`
`may be treated with a suitable acid, either neat or in a suitable solution, and the
`
`resulting salt isolated either by filtration or by evaporation under vacuum of the
`
`Pharmaceutically acceptable base addition salts may be
`reaction solvent.
`obtained in an analogous manner by treating a solution of compound A or B
`
`with a suitable base. Both types of salt may be formed or interconverted using
`ion-exchange resin techniques.
`
`Compounds of the invention may be isolated in association with solvent
`molecules by crystallisation from or evaporation of an appropriate solvent.
`
`The syntheses of compounds A and B and of the intermediates for use
`
`therein are illustrated by the following examples. The examples have been
`
`previously described in
`
`the priority document of
`
`the instant
`
`invention
`
`GBQ514464.8, and the corresponding Intermediate or Example numbers therein
`are shown in parentheses'next to the current lnterrnediate or Example number.
`
`In the Examples section hereinafter the following abbreviations are used:
`
`1O
`
`15
`
`20
`
`MeOH (methanol) and EtOH (ethanol),
`
`
`bin
`le--rb l
`iio r
`
`25
`
`30
`
`To a stirred solution of D-tryptophan methyl ester (11 g) and piperonal (7.9 g) in
`
`anhydrous CHZCIZ (400 mL) cooled at 0°C was added dropwise trifluoroacetic
`acid (7.7 mL) and the solution was allowed to react at ambient temperature.
`
`After 4 days, the yellow solution was diluted with CH2C12 (200 mL) and washed
`With a saturated aqueous solution of NaHCO3, then with water (3x200 mL) and
`dried over Na2804. The organic layer was evaporated under reduced pressure
`and the residue containing the two geometric isomers was purified by flash
`
`ATI 1005-0011
`
`ATI 1005-0011
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`10
`
`chromatography eluting with dichloromethanelethyl acetate (97/3) to give as the
`firsr eluting product thejflecgmpgund (6.5 g)
`
`m.p.:154°C
`
`W53)
`
`1
`
`RM l1 4-rhr--2-hlrrin|-1-4-
`
`mhleni
`
`nl-H-r'
`
`4-inl--aroxla
`
`10
`
`To a solution of (R)—(+)-2-chloropropionic acid (191 pl, 2.2 mmol) in anhydrous
`dichloromethane (30 mL), was added dicyclohexylcarbodiimide
`(0.45 g,
`2.2. mol). Intermediate 1 (0,7 g, 2 mmol) was then added and the mixture was
`stirred at
`room temperature for 20 hours. The formed precipitate of
`dicyclohexylurea was removed by filtration, the filtrate was evaporated in vacuo
`and the crude product was purified by flash chromatography eluting with
`toluene/ethyl acetate: 95/5. The oily compound obtained was then crystallised
`from ether/hexane to give thejflmmpgugg as pale yellow crystals (0.74 9)
`
`15
`
`mp. : 126-128°C.
`
`e 1 7
`
`(QR,12aR)-2,3,§,7,12.1Za-Hexahydrg-2-mejhyl-6-(3,4-methylenedioxyphenyl)-
`l "'1 i
`-bi
`l-14'
`
`20
`
`25
`
`30
`
`in
`(0.5 g) and NaHCO3 (0.14 g)
`a) To a stirred solution of intermediate 1
`anhydrous CHC|3 (20 mL) was added dropwise chloroacetyl chloride (0.27 mL)
`at 0°C. The resulting mixture was stirred for 1 hour at the same temperature
`and diluted with CHCI3 (20 mL). Water (10 mL) was then added dropwise with
`stirring to the mixture, followed by a saturated solution of NaHCO3. The organic
`layer was washed with water until neutrality and dried over Na2804. After
`evaporation of the solvent under reduced pressure, (6R 12aR)-methyl 1 2 3 4-
`r -2-
`l r
`I-1-
`4-
`h I
`'
`l- H-
`rid 34-b indoe~
`
`3-garboxyla1e was obtained as an oil which was crystallised from ether to give a
`solid (0.38 9, mp. : 233°C) which was used without further purification in the
`next step.
`
`the chloroacetyl intermediate (0.37 g) in MeOH
`b) To a stirred suspension of
`(20 mL) was added at room temperature a solution of methylamine (33% in
`
`ATI 1005-0012
`
`ATI 1005-0012
`
`

`

`W0 97/03675
`
`PCT/EP96/03024
`
`11
`
`EtOH) (0.4 mL) and the resulting mixture was heated at 50°C under N2 for
`16 hours. The solvent was removed under reduced pressure and the residue
`
`was dissolved in CHZCIZ (50 mL). After washing with water (3x20 mL), drying
`over Na2804 and evaporating to dryness, the residue was purified by flash
`chromatography eluting with CH2Cl2lMeOH (99/1) and recrystallised from 2-
`propanol to give the titlemmpgund as white crystals (0.22 g)
`
`m.p. : 302-303°C.
`
`Analysis for 022H19N304:
`
`Calculated:C,67.86;H,4.92;N,10.79;
`
`10
`
`Found:C,67.77;H,4.92;N,10.74%.
`
`[(112000 = +71 .0° (C=1.00; CHCl3)-
`
`15
`
`20
`
`
`
`To a stirred solution of intermediate 2 (0.3 g, 0.68 mmol) in THF (30 mL) was
`added at room temperature a solution of methylamine (33 % in EtOH) (0.68 mL)
`and the resulting solution was treated at reflux under N2 for 6 days. The solvent
`was removed under reduced pressure and the residue was dissolved in CHZCIZ
`(50 mL). After washing with water
`(2,25 mL), drying over Na2804 and
`evaporating to dryness, the crude product was purified by flash chromatography
`eluting with dichloromethane/methanol : 99/1. The oily residue obtained was
`crystallised from methanol to give the title compound as white crystals (40 mg)
`m.p. : 307-309°C.
`
`25
`
`Analysis for CZ3H21N304 :
`
`Calculated :
`
`C, 68.47 ; H, 5.25 ; N, 10.42 ;
`
`Found :
`
`C, 68.35; H, 5.33; N, 10.42%.
`
`[<1]20°D = + 652° (c = 1.15 ; CHCI3).
`
`ATI 1005-0013
`
`ATI 1005-0013
`
`

`

`W0 97/03675
`
`PCT/EP96/03024
`
`12
`
`The following compound was similarly prepared:
`
`Exemolej
`
`hl
`
`'
`
`n l-
`
`i
`
`'
`
`"
`
`'
`
`4-
`
`'
`
`le-14-di neaswhite
`
`crystals using ammonia as the base.
`
`m.p. : 319-321°C.
`
`Analysis for 022H19N304 I
`
`Calculated : C, 67.86 ; H, 4.92 ; N, 10.79 ;
`
`Found :
`
`C, 67.86; H". 5.17; N, 10.72%.
`
`10
`
`[0420]) = + 107° (c = 1 ; pyridine).
`
`Compounds A and B have been included in pharmacy formulations and details
`of such formulations are given below.
`
`15
`
`TABLET§ FQR ORAL ADMINISTBA ! lQN
`
`A.
`
`Dr
`
`mr
`
`i
`
`Active ingredient
`
`mgltablet
`
`50.0
`
`
`
`
`
`
`
`
`Crospovidone USNF
`
`Magnesium Stearate Ph Eur
`
`Anhydrous Lactose
`
`The active ingredient was sieved and blended with the excipients. The
`resultant mix was compressed into tablets.
`
`ATI 1005-0014
`
`ATI 1005-0014
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`13
`
`Active ingredient
`
`Colloidal Silicon Dioxide
`
`Crospovidone
`
`Sodium Lauryl Sulphate
`
`
`
`
`
`Magnesium Stearate Ph Eur
`
`
`Microcrystalline Cellulose USNF
`
`The active ingredient was sieved and blended with the excipients. The
`
`resultant mix was compressed into tablets.
`
`B.
`
`WEI QBANULATIQN
`
`Active ingredient
`
`Polyvinyl pyrollidone
`
`Polyethylene glycol
`
`Polysorbate 80
`
`Microcrystalline Cellulose USNF
`
`Magnesium Stearate Ph Eur
`
`Croscarmellose Sodium
`
`Colloidal Silicon Dioxide
`
`ATI 1005-0015
`
`ATI 1005-0015
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`14
`
`The polyvinyl pyrollidone, polyethylene glycol and polysorbate 80 were
`dissolved in water. The resultant solution was used to granulate the
`active ingredient. After drying the granules were screened, then extruded
`
`at elevated temperatures and pressures. The extrudate was milled
`and/or screened then was blended with the microcrystalline cellulose,
`croscannellose sodium, colloidal silicon dioxide and magnesium stearate.
`The resultant mix was compressed into tablets.
`
`Active ingredient
`
`Polysorbate 80
`
`Lactose Ph Eur
`
`Magnesium Stearate BP
`
`Starch BP
`
`Pregelatinised Maize Starch BP
`
`The active ingredient was sieved and blended with the lactose, starch
`and pregelatinised maize starch. The polysorbate 80 was dissolved in
`purified water. Suitable volumes of the polysorbate 80 solution were
`added and the powders were granulated. After drying, the granules were
`screened and blended with the magnesium stearate. The granules were
`then compressed into tablets.
`'
`
`Tablets of other strengths may be prepared by altering the ratio of active
`ingredient to the other excipients.
`
`FILM QOAI ED TABLE. I §
`
`The aforementioned tablet formulations were film coated.
`
`5
`
`10
`
`15
`
`ATI 1005-0016
`
`ATI 1005-0016
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`15
`
`to 100.0*
`
`13.2
`
`Opadry whiteT
`
`Purified water Ph Eur
`
`* The water did not appear in the final product. The maximum theoretical weight
`of solids applied during coating was 20mg/tablet.
`
`1' Opadry white is a proprietary material obtainable from Colorcon Limited, UK
`which contains hydroxyprOpyl methylcellulose, titanium dioxide and triacetin.
`
`The tablets were film coated using the coating suspension in conventional film
`
`coating equipment.
`
`QAESLLLEfi
`
`10
`
`Active ingredient
`
`Polyvinyl pyrollidone Magnesium Stearate
`
`Lactose
`
`The active ingredient was sieved and blended with the excipients. The mix was
`
`filled into size No. 1 hard gelatin capsules using suitable equipment.
`
`Active ingredient
`
`Microcrystalline Cellulose
`
`
`
`
`Sodium Lauryl Sulphate
`
`ATI 1005-0017
`
`ATI 1005-0017
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`16
`
`Crospovidone
`
`Magnesium Stearate
`
`The active ingredient was sieved and blended with the excipients. The mix was
`filled into size No. 1 hard gelatin capsules using suitable equipment.
`
`Other doses may be prepared by altering the ratio of active ingredient to
`excipient, the fill weight and if necessary changing the capsule size.
`
` Active ingredient
`
`mglcapsule
`
`50.0
`
` Labrafil M1944CS
`
`to 1.0 ml
`
`The active ingredient was sieved and blended with the Labrafil. The suspension
`was filled into soft gelatin capsules using appropriate equipment.
`
`10
`
`Inhibitory effect on cGMP-PDE
`
`cGMP-PDE activity of compounds of the present invention was measured using
`a one-step assay adapted from Wells at al. (Wells, J. N., Baird, C. E., Wu, Y. J.
`
`and Hardman, J. G., Biochim. Biophys. Acta 384, 430 (1975)). The reaction
`
`15
`
`medium contained 50mM Tris-HC|,pH 7.5, 5mM Mg-acetate, 250pg/ml 5’-
`Nucleotidase, 1mM EGTA and 0.15uM 8-[H3]-cGMP. The enzyme used was a
`
`human recombinant PDE V (ICOS, Seattle USA).
`
`Compounds of the invention were dissolved in DMSO finally present at 2% in
`
`20
`
`the assay. The incubation time was 30 minutes during which the total substrate
`conversion did not exceed 30%.
`
`The
`
`|C5o values
`
`for
`
`the compounds
`
`examined were determined from
`
`concentration-response curves using typically concentrations ranging from 10nM
`to 10pM. Tests against other PDE enzymes using standard methodology also
`
`ATI 1005-0018
`
`ATI 1005-0018
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`17
`
`showed that compounds of the invention are highly selective for the cGMP
`
`specific PDE enzyme.
`
`-cGMP level measurements
`
`5
`
`Rat aortic smooth muscle cells (RSMC) prepared according to Chamley et al. in
`
`Cell Tissue Res. 111, 503 - 522 (1977) were used between the 10th and 25th
`
`passage at confluence in 24-well culture dishes. Culture media was aspirated
`
`and replaced with PBS (0.5ml) containing the compound tested at
`
`the
`
`appropriate concentration. After 30 minutes at 37°C, particulates guanylate
`
`10
`
`cyclase was stimulated by addition of ANF (100nM) for 10 minutes. At the end
`
`of incubation, the medium was withdrawn and two extractions were performed
`
`by addition of 65% ethanol (0.25ml). The two ethanolic extracts were pooled
`
`and evaporated until dryness, using a Speed-vac system.
`
`c-GMP was
`
`measured
`
`after
`
`acetylation
`
`by
`
`scintillation
`
`proximity
`
`immunoassay
`
`15
`
`(AMERSHAM).
`
`The compounds according to the present invention were typically found to
`
`exhibit an leEJ value of less than 500nM, and an EC5(J value of less than 5.
`
`In
`
`vitro test data for representative compounds of the invention is given in following
`
`20
`
`Table 1:
`
`Table 1
`
`Example No.
`
`
`
`
`
`
`
`25
`
`The above data demonstrates the ability of the subject compounds of the
`
`invention to inhibit cGMP PDE, and hence their utility in the treatment of erectile
`
`dysfunction substantially as hereinbefore described.
`
`ATI 1005-0019
`
`ATI 1005-0019
`
`

`

`WO 97/03675
`
`PCT/EP96/03024
`
`18
`
`
`CLAIMS
`
`1. Use of a compound of formula (I):
`
`(I)
`
`and salts and solvates (e.g. hydrates) thereof, in which:
`
`R0 represents hydrogen, halogen or C1_5 alkyl;
`R1 represents hydrogen, C1_5alkyl,