3-PYRIDINOL DERIVATIVES AND THEIR USE AS MEDICAMENTS

Abstract: Compounds of formula (1), or a pharmaceutically acceptable salt thereof, wherein: R<0> is OH or a bioprecursor thereof, R<1> is A<0>CO2H, P(Z)(OH)(OR<2>), SO2H, SO3H or 5-tetrazolyl or a bioprecursor thereof, A<0> is CH2, CHF, CF2, CR<3>(OR<4>), CO or C(OR<5>)(OR<6>), are described as agonists of a cyclic AMP dependent protein kinase. They are useful as medicaments.

Description: 3-PYRIDIN0L DERIVATIVES AND THEIR USE AS MEDICAMENTS. The present invention relates to pyridinol derivatives, processes for their preparation, intermediates in their preparation, their use as medicaments and to pharmaceutical compositions comprising them. The compounds of this invention are agonists of a cyclic A P- dependent protein kinase (cA-PrK) (see J. Biol. Chem., 1989, 264, 8443 - 8446) and are of use in combatting such conditions where such agonism is thought to be beneficial. They are likely to have anti-proliferative, anti-aggregatory, cholesterol-lowering, smooth muscle relaxant, positive lusitropic, anti-allergic or anti-inflammatory activities. They are likely to be useful in the treatment of cardiovascular diseases where there is a component of diastolic failure, cancer, psoriasis, atheroschlerosis, thrombosis, re-stenosis, chronic reversible lung disease such as asthma and bronchitis, allergic disease such as allergic asthma, allergic rhinitis and urticaria or gut motility disorders such as irritable bowel syndrome. Accordingly the present invention provides compounds of the formula (1) : or pharmaceutically acceptable salts thereof, wherein : R- is OH or a bioprecursor thereof, R 1 is A°Cθ2H, P(Z) (OH) (OR 2 ), SO2H, SO3H or 5-tetrazolyl or a bioprecursor thereof, A° is CH 2 , CHF, CF 2 , CR 3 (OR 4 ), CO or C(OR 5 ) (OR 6 ), R 2 is phenyl, C3_5cycloal yl, C3_5cycloalkylCι_4al yl, or Ci- β alkyl optionally substituted by Cι_4al oxy, R3 is H, methyl or ethyl, R 4 is H or Cι_3alkyl, R and R^ are each C^-^al yl or together form a 1,2- ethanediyl group or 1,3-propanediyl group, Z is 0 or S, and Ar is phenyl optionally substituted by one to three groups independently selected from C]__galkyl, C2-63-lkenyl, Ci-ςalkoxy, C3_galkenyloxy, C3_gcycloalkyl, C3__gcycloalkoxy, C _galkylthio, phenyl, phenylthio, benzyloxy, Ci-gpolyfluoroalkyl, Ci-gpolyfluoroalkoxy, halo, N(R 7 )2 or NHCOR 7 wherein R 7 is H or Ci-galkyl, or -X(CH2) n Y- attached to adjacent carbon atoms of the phenyl ring wherein X and Y are independently CH2 or 0 and n is 1 to 3, wherein said C^-galkyl, C2-galkenyl or Cι_galkoxy groups can be independently substituted by OH, C _galkoxy, C3_6cycloal yl, N(R 7 )2, CO2R 7 or CON(R 7 )2, or Ar is 1-naphthyl optionally substituted in the 4-position by hydroxy or C _galkoxy, 2-naphthyl optionally substituted in the 1-position by hydroxy or C^-galkoxy, 3-phenanthryl, 9-phenanthryl, 2-quinolinyl, 4-quinolinyl, 3-thianaphthenyl or 2-benzofuranyl. Bioprecursors of the groups R- and R^ are derivatives thereof which are convertible in vivo into the groups R- and R^. A suitable bioprecursor of the group R^ is OR* wherein ^ is Cι_4al noyl (for example acetyl) , arylCι_4alkanoyl (for example phenyl Cι-4al anoyl such as benzoyl) , arylsulphonyl (for example optionally substituted phenylsulphonyl or toluenesulphonyl) or Cι_ alkylsulphonyl (for example methylsulphonyl) . When R 1 is A^Cθ2H a suitable bioprecursor is A^Cθ2R^ wherein R 9 is an ester-forming group. When Rl is P(Z) (OH) (OR 2 ) a suitable bioprecursor is P(Z) (OR 2 )2 wherein Z and R 2 are as hereinbefore defined or P(Z) (OR 2 ) (OR 1 ^) wherein R 10 is an O-protecting group. Suitable O-protecting groups include pivaloyloxymethyl, propionyloxymethyl and pivalolyloxycarbonyloxymethyl. When R 1 is 5-tetrazolyl, a suitable bioprecursor is an N-protected derivative thereof. Suitable N-protecting groups include pivalolyloxymethyl, propionyloxymethyl and pivalolyloxycarbonyloxymethyl. Alternatively bioprecursors of the groups R- and R~- are those formed when R 1 and R^ are linked together to form a cyclic structure such that R1-R0 is A!C02 or A 2 OCH2θ, in which : A 1 is CH 2 , CHF, CF 2 , CR 3 (OR 4 ), CO or C(OR 5 ) (OR 6 ), A 2 is P(Z)OR 2 or CR 3 (CO2R 9 ) , and R 2 to R 6 , R 9 and Z are as hereinbefore defined. Suitably R^ is hydroxy or OR^, preferably hydroxy. Suitably R 1 is A°C0 2 H or A°C0 2 R 9 . Suitably R 1 is P(Z) (OH) (OR 2 ) or P(Z) (OR 2 ) 2 - Suitably R 1 is SO2H, SO3H or 5-tetrazolyl. Suitably R 1 and R° are linked together such that R^R 0 is A 1 Cθ2. Suitably R 1 and R° are linked together such that R 1 -R° is A 2 OCH2θ. By the term alkyl is meant both straight- and branched- chain alkyl. By the term Ci-gpolyfluoroalkyl is meant a Ci-galkyl group having at least one hydrogen replaced with fluoro, e.g. CF3 or CF2CF2H. Suitably R 2 is methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-methoxyethyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclopropylmethyl. Suitably R 3 is H, methyl or ethyl, preferably H or methyl. Suitably R 4 is H, methyl, ethyl or propyl, preferably H or methyl. Suitably R 5 and R 6 are independently methyl, ethyl or propyl, preferably together they form a 1,2-ethanediyl group. Preferably Z is 0. Suitably R 9 is Cι_ alkyl optionally substituted by hydroxy, e.g. 2-hydroxyethyl or arylCι_4alkyl (for example phenylCι_4alkyl such as benzyl) . Suitably Ar is phenyl optionally mono-substituted by a group as hereinbefore defined, for example in the 2,3, or 4 positions by Cι_galkyl, C^-galkoxy, C3_galkenyloxy, Cι_galkylthio, phenyl, phenylthio, benzyloxy, CF3, halo or NHCOR 7 . Suitably Ar is phenyl di-substituted by any groups as hereinbefore defined, for example in the 3,4-,3,5-,2,3-,2,4- or 2,5-, positions by groups independently selected from C2-galkenyl, Ci-galkoxy, C3«gcycloalkoxy, halo, -X(CH2) n Y- or alkoxy. Suitably Ar is phenyl trisubstituted by any groups as hereinbefore defined, for example in the 2,3,4-, 2,3,5-, or 3, ,5-positions by groups independently selected from C2-galkenyl, Cι_galkoxy or halo. Suitably Ar is 1-naρhthyl optionally substituted in the 4-position by hydroxy or C^-galkoxy. Suitably Ar is 2-naphthyl optionally substituted in the 1-position by hydroxy or C^-galkoxy. Suitably Ar is 3-phenanthryl or 9-phenanthryl. Suitably Ar is 2-quinolinyl or 4-quinolinyl. Suitably Ar is 2-benzofuranyl or 3-thianaphthenyl. Examples of C^-galkoxy include methoxy, ethoxy, propoxy, butoxy, or pentyloxy. Examples of C ] __galkyl include methyl, ethyl, propyl, butyl, isobutyl or pentyl. Examples of halo include fluoro, chloro, bromo or iodo. Particular compounds of this invention include : ethyl [5-(2-naphthyl)-3-hydroxy-2-pyridyl]phosphonate, 5-(2,4-dipropoxyphenyl)-2-(5-tetrazolyl)pyridin-3-ol, or 5- (4-methoxy-3-propoxyphenyl)-3- (5-tetrazolyl)pyridin-3-ol, and pharmaceutically acceptable salts thereof. This invention covers all tautomeric, geometric and optical isomeric forms of compounds of formula (1) . Compounds of the formula (1) can form pharmaceutically acceptable base addition salts with metal ions, such as alkali metals for example sodium or potassium, or with an ammonium ion. In order to use a compound of the formula (1) or a pharmaceutically acceptable salt thereof for the treatment o humans and other mammals it is normally formulated in accordance with standard pharmaceutical practice as a pharmaceutical composition. Compounds of formula (1) and their pharmaceutically acceptable salts may be administered in standard manner for the treatment of the indicated diseases, for example orally, sublingually, parenterally, transdermally, rectally, via inhalation or via buccal administration. Compounds of formula (1) and their pharmaceutically acceptable salts which are active when given orally or via buccal administration can be formulated appropriately in dosage forms such as liquids, syrups, tablets, capsules and lozenges. An oral liquid formulation will generally consist of a suspension or solution of the compound or salt in a liquid carrier for example, ethanol, glycerine or water with a flavouring or colouring agent. Where the composition is in the form of a tablet, any pharmaceutical carrier routinely used for preparing solid formulations may be used. Examples of such carriers include starch, celluloses, lactose, sucrose and magnesium stearate. Where the composition is in the form of a capsule, any routine encapsulation is suitable, for example using the aforementioned carriers in a hard gelatin capsule shell. Where the composition is in the form of a soft gelatin shell capsule, any pharmaceutical carrier routinely used for preparing dispersions or suspensions may be considered, for example aqueous gums, celluloses, silicates or oils and are incorporated in a soft gelatin capsule shell. Typical parenteral compositions consist of a solution or suspension of the compound or salt in a sterile aqueous or non-aqueous carrier optionally containing a parenterally acceptable oil or solubilising agent, for example polyethylene glycol, polyvinylpyrrolidone, lecithin, 2-pyrrolidone, cyclodextrin, arachis oil, or sesame oil. A typical suppository formulation comprises a compound of formula (1) or a pharmaceutically acceptable salt thereof which is active when administered in this way, with a binding and/or lubricating agent, for example polymeric glycols, gelatins, cocoa-butter or other low melting vegetable waxes or fats or their synthetic analogues. Typical transdermal formulations comprise a conventional aqueous or non-aqueous vehicle, for example a cream, ointment, lotion or paste or are in the form of a medicated plaster, patch or membrane. Typical compositions for inhalation are in the form of a solution, suspension or emulsion that may be administered in the form of an aerosol using a conventional propellant such as dichlorodifluoromethane or trichlorofluoromethane, or are in the form of a powder for insufflation. Preferably the composition is in unit dosage form, for example a tablet, capsule or metered aerosol dose, so that the patient may administer to himself a single dose. Each dosage unit for oral administration contains suitably from 0.001 mg/Kg to 30 mg/Kg, and preferably from 0.005 mg/Kg to 15 mg/Kg, and each dosage unit for parenteral administration contains suitably from 0.001 mg/Kg to 10 mg/Kg, of a compound of formula (1) or a pharmaceutically acceptable salt thereof calculated as the free acid. The daily dosage regimen for oral administration is suitably about 0.001 mg/Kg to 120 mg/Kg, of a compound of formula (1) or a pharmaceutically acceptable salt thereof calculated as the free acid. The daily dosage regimen for parenteral administration is suitably about 0.001 mg/Kg to 40 mg/Kg, for example about 0.005 mg/Kg to 10 mg/Kg, of a compound of the formula (1) or a pharmaceutically acceptable salt thereof calculated as the free acid. The active ingredient may be administered as required for example from 1 - 8 times a day or by infusion. The compositions of the invention are agonists of a cA-PrK and are of use in combatting such conditions where such agonism is thought to be beneficial. Such conditions can be treated by administration orally, sublingually topically, rectally, parenterally or by inhalation. For administration by inhalation dosages are controlled by a valve, are administered as required and for an adult are conveniently in the range 0.1 - 5.0 mg of a compound of the formula (1) or a pharmaceutically acceptable salt thereof. The compounds of this invention may be co-administered with other pharmaceutically active compounds, for example in combination, concurrently or sequentially. Conveniently the compounds of this invention and the other active compound or compounds are formulated in a single pharmaceutical composition. Examples of compounds which may be included in pharmaceutical compositions with the compounds of the formula (1) are bronchodilators such as sympathomimetic amines for example isoprenaline, isoetharine, sulbutamol, phenylephrine and ephedrine or xanthine derivatives for example theoph lline and aminophylline, anti-allergic agents for example disodium cromoglycate, histamine H 1 ~antagonists, drugs used in the treatment of cancer such as those which inhibit the synthesis of or inactivate DNA, for example methotrexate, fluoracil, cisplatin, actinomycin D, anti- atherschlerotic agents for example cholesterol lowering drugs such as HMGCoA reductase inhibitors, bile acid sequestrants, drugs for the treatment of psoriasis, for example retinoids, anthralin, anti-inflammatories for example cortiscosteroids, non-steroid anti-inflammatories such as aspirin, antithrombotics for example dipyridamole, or fibrinolytic agents. In another aspect the present invention provides a process for the preparation of compounds of the formula (1) or pharmaceutically acceptable salts thereof, which process comprises : a) for compounds wherein R 1 is A^C02H or AOCO2R 9 and : i) A 0 is CR 3 (OR 4 ) , reacting in the presence of a strong base a compound of the formula (2) : wherein R^ is an O-protecting group and Ar is as hereinbefore defined, with a compound of the formula (3) : R 3 COCθ2 9 (3) wherein R 3 and R 9 are as hereinbefore defined to form a compound of the formula (4) : wherein R 12 is CR 3 (OH)Cθ2R 9 and R 3 , R 9 , R 11 , and Ar are as hereinbefore defined and thereafter optionally reacting with a Cι_3alkylating agent to form the corresponding compound wherein R 12 is CR 3 (OC^alkyl)CO2R 9 , ii) A° is CO, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with a compound of the formula (5) : 9 0 2 CC0 9 (5) wherein R 9 is as hereinbefore defined to form a compound of the formula (4) wherein R 12 is COCO2R 9 and R 9 , R 11 and Ar are as hereinbefore defined, iii) A° is CH(OH), reacting a compound of the formula (4) wherein R^- is COCO2R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a reducing agent to form the corresponding compound wherein R 12 is CH(OH)C02R 9 , iv) A 0 is CH 2 , reacting a compound of the formula (4) wherein R^ 2 is COCO2H or COCO2R 9 and R 9 , R^, and Ar are as hereinbefore defined with a suitable reducing agent to form the corresponding compound wherein R 12 is CH2CO2H, v) A° is C(OR 5 ) (OR 6 ), reacting a compound of the formula (4) wherein R^- 2 is COCO2 and R 9 , R 11 , and Ar are as hereinbefore defined with a Cι_3alco ol, 1,2-ethanediol or 1,3-propanediol to form the corresponding compound wherein R 12 is C(0R 5 ) (0R 6 )C02R 9 , vi) A 0 is CF , reacting a compound of the formula (4) wherein R 12 is COCO2R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a fluorinating agent to form the corresponding compound wherein R 11 is CF2CO2 9 , or vii) A° is CHF, reacting a compound of the formula (4) wherein R^ 2 is CH(0H)C02R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a fluorinating agent to form the corresponding compound wherein R 12 is CHFCO2R 9 , and thereafter optionally : ° converting the group OR-^ into OH 0 converting the group A^Cθ2R 9 into A°Cθ2H; or b) for compounds wherein R 1 is CH2CO2H, converting a compound of the formula (6) : wherein R 13 is acetyl and Ar is as hereinbefore defined into the corresponding compound wherein R^ 3 is CH2CO2H; or c) for compounds wherein R 1 is CH(OR 4 )C02H reacting a compound of the formula (4) wherein R 12 is -CH(OH)CN with a C]__3alkylating agent and/or converting the group CN into CO2H, and optionally converting the group OR 1 * into OH; or d) for compounds wherein R 1 is P (0) (OH) (OR 2 ), hydrolysing a compound of the formula (6) wherein R 13 is P (0) (OR 2 )2 and R 2 , and Ar are as hereinbefore defined; or e) for compounds wherein R- is P(S) (OH) (OR 2 ), converting a compound of the formula (6) wherein R 13 is P(0) (NHR 14 ) (OR 2 ) and R 14 is phenyl or Cι_ alkyl and Ar is as hereinbefore defined into the corresponding compound wherein R 13 is P(S) (OH) (OR 2 ); or f) for compounds where R 1 is SO3H, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with sulphuryl chloride or a chemical equivalent thereof and optionally converting the group OR 11 into OH; or g) • for compounds wherein R 1 is SO2H, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with sulphur dioxide and optionally converting the group OR 11 into OH; or h) for compounds wherein R~- is 5-tetrazolyl, reacting a compound of the formula (4) wherein R^- 2 is cyano or a compound of the formula (6) wherein R^ 3 is cyano with an azide salt and thereafter if necessary converting the group OR 11 into OH; or i) for compounds wherein R^ is as defined for compounds of the formula (1) reacting in the presence of a palladium catalyst a compound of the formula (7) : wherein R 3 is a group Rl as hereinbefore defined or a precursor thereof and R a is a group R- as hereinbefore defined or a precursor thereof and L is a leaving group 1 a compound of the formula (8) : ArB(OH) 2 (8) or a chemical equivalent thereof wherein Ar is as hereinbefore defined and then, if necessary, converting a precursor of R 1 into R^ and/or converting a precursor of R^ into R0' and optionally thereafter : ° forming a bioprecursor of R^ and/or R 1 ° forming a pharmaceutically acceptable salt. Suitably a compound of the formula (2) is reacted with a strong base such as lithium diisopropylamide, or a Cι- , alkyl lithium or aryl lithium such as mesityl lithium in an organic solvent such as tetrahydrofuran, diethylether or dimethoxyethane with cooling (-100° - 0°C) to form the anion thereof. The strong base may be formed in situ, for example by the addition of a Cι_4alkyl lithium e.g. methyllithiu followed by a catalytic quantity of diisopropylamine. The anion of a compound of the formula (2) is suitably reacted with, a compound of the formula (3) or a compound of the formula (5) in an organic solvent such as tetrahydrofuran, diethylether or dimethoxyethane with cooling (-100° to 0°C) to form a compound of the formula (4) wherein R 12 is CR 3 (OH)Cθ2R 9 or COCO2R 9 respectively. A suitable compound of the formula (3) is ethylpyruvate, or ethyl glyoxylate or a chemical equivalent thereof and a suitable compound of the formula (5) is diethyloxalate. A compound of the formula (4) wherein R 12 is CR 3 (OH)C02R 9 is suitably reacted with a Cι_3alkylating agent such as iodomethane, iodopropane or dimethylsulphate in the presence of a base such as sodium hydride or potassium hydroxide in an organic solvent such as dimethylformamide or dimethylsulphoxide at elevated (e.g. 30 - 80°C) or preferably ambient temperature to form the corresponding compound wherein R 12 is CR 3 (OCι_3alkyl)C0 R 9 . When potassium hydroxide is used as base the CO2 9 group may be directly converted to carboxy. A compound of the formula (4) wherein R 12 is COCO2R 9 is suitably reacted with a reducing agent such as sodium borohydride, or diisobutylaluminium hydride in an organic solvent such as dichloromethane, a Cι_4alcohol e.g. ethanol, or acetic acid or mixtures thereof at ambient or elevated temperature (e.g. 30 - 80°C), or with cooling (e.g. 0 - 5°C) to form the corresponding compound wherein R^ is CH(OH)C0 2 R 9 • A compound of the formula (4) wherein R 12 is COCO2H or COCO2R 9 is suitably reacted with a reducing agent such as a zinc amalgam in hydrochloric acid in the absence of a solvent or in a solvent such as ethanol, acetic acid or dioxan and hydrogen chloride gas at ambient or elevated temperature (e.g. 40-100°C) to form the corresponding compound wherein R12 i s CH2CO2H. Under these reaction conditions the CO2R 9 group is converted to carboxy. A compound of the formula (4) wherein R^ is COCO2R is suitably reacted with a Cχ-3alcohol, 1,2-ethanediol or 1,3- propanediol in the presence of an acid catalyst such as paratoluenesulphonic acid, concentrated sulphuric acid or anhydrous hydrogen chloride, at ambient or elevated temperature to form the corresponding compound wherein R^ 2 is C(OR 5 ) (OR 6 )C02R 9 . A compound of the formula (4) wherein R 12 is COCO2R or CHOHCO2R 9 is suitably reacted with a fluorinating agent such as diethylaminosulphur trifluoride in an organic solvent such as a halohydrocarbon or an ether such as glyme, or THF at ambient or elevated temperature (e.g. 30-60°C) to form the corresponding compound where R 12 is CF2CO2R 9 or CHFCO2R 9 respectively. Examples of O-protecting groups for R 11 include methyl or benzyl. A compound of the formula (4) wherein OR- 1 - 1 is methoxy can suitably be converted to the corresponding compound wherein OR 11 is hydroxy by reaction with sodium iodide and chlorotrimethylsilane in an organic solvent such as acetonitrile, or a halohydrocarbon e.g. dichloromethane or chloroform at elevated (e.g. 30 - 80°C) or preferably ambient temperature. This method is particularly suitable for preparing compounds of the formula (1) wherein R 1 is A^C02R 9 since the ester-forming group R 9 is not hydrolysed under the reaction conditions. Another method utilises sodium thiomethoxide in an organic solvent such as dimethylformamide at an elevated temperature for example 40 - 120°C. The more forcing conditions of this method are suitable for preparing compounds of formula (1) wherein R- is AOCO2H. Alternatively a compound of the formula (4) wherein OR 11 is benzyloxy can be converted to the corresponding compound wherein OR 11 is hydroxy in conventional manner, for example catalytic hydrogenation on palladium on carbon or reacting with sodium in liquid ammonia. A compound of the formula (4) wherein R 12 is A0CO R 9 can suitably be converted to the corresponding compound wherein R 12 is A^C02H by reaction with an aqueous base such as sodium or potassium hydroxide at ambient or elevated temperature (e.g. 40 - 120°) . This method is particularly suitable for preparing compounds of the formula (1) wherein R- is methoxy since the OR 11 group is not hydrolysed. Another hydrolysis method utilises aqueous acid such as concentrated hydrochloric acid at an elevated temperature (e.g. 40 - 120°C) which provides directly compounds of the formula (1) wherein R° is hydroxy and R 1 is A°Cθ2H. Suitably a compound of the formula (6) wherein R 13 is acetyl is converted to the corresponding compound where R 13 is CH2CO2H by reaction with sulphur and morpholine at elevated temperature (e.g. 50 - 200°C) , followed by hydrolysis with an aqueous base such as sodium hydroxide at elevated temperature, preferably at the reflux temperature of the reaction mixture. Suitably a compound of formula (4) where R 12 is -CH(OH)CN is reacted with a C ] __3alkylating agent as hereinbefore described followed by reaction with aqueous mineral acid such as hydrochloric acid at ambient or elevated temperature, preferably at reflux in order to prepare the corresponding compound where R 12 is CH(OCι_3alkyl) CO2H. The alkylation can be omitted if the corresponding compound where R 12 is CH(OH)Cθ2H is desired. During the hydrolysis of the CN group the OR 11 group may be converted to hydroxy. If not and if desired this group can be converted to hydroxy as hereinbefore described. A compound of the formula (4) wherein R 12 is -CH(0H)CN can be prepared by reacting the corresponding compound wherein R 12 is -CHO with a source of cyanide such as potassium cyanide in the presence of acid such as hydrochloric acid, preferably at ambient temperature. A compound of the formula (4) or (6) where R 12 or R 13 is CHO is suitably prepared by reacting the corresponding compound wherein R 1 or R 1 is cyano with a suitable reducing agent such as diisobutylaluminium hydride followed by aqueous acidic work-up. Suitably a compound of the formula (6) wherein R 13 is P(O) (OR 2 )2 is hydrolysed by reaction with an aqueous base such as sodium hydroxide optionally in a cosolvent such as a Cι_4alco ol at an elevated temperature (e.g. 40-100°C), preferably at the reflux temperature of the reaction mixture. Suitably a compound of the formula (6) wherein R 13 is (0) (NHR 14 > (OR 2 ) is converted to the corresponding compound wherein R 9 is (S) (OH) (OR 2 ) by reaction with a strong base such as sodium hydride in an organic solvent such as dimethoxyethane at ambient or elevated temperature, (e.g. 40 - 100°C) followed by reaction with carbon disulphide. Suitably the anion of a compound of the formula (2) prepared as hereinbefore described is reacted with sulphuryl chloride or a chemical equivalent thereof or with sulphur dioxide in an organic solvent such as tetrahydrofuran with cooling (- 100° - 0°C) to form after aqueous work-up a compound of the formula (4) wherein R 12 is SO3H or S0 2 H respectively and OR 1 is as hereinbefore defined which if desired can be converted to the corresponding compound wherein OR 11 is hydroxy as hereinbefore described. A compound of the formula (4) wherein R 12 is cyano or a compound of the formula (6) wherein R 13 is cyano is suitably reacted with an azide salt such as ammonium, sodium or aluminium azide in an organic solvent such as dimethyl- formamide, dimethylsulphoxide, N-methylpyrrolidone or tetrahydrofuran at an elevated temperature e.g. 40-200°C, preferably at 100-150°C to form the corresponding 5-tetrazolyl compound. Preferably in a compound of the formula (4) OR 11 is benzyloxy since this group is converted directly to hydroxy under the reaction conditions. Suitably a compound of the formula (7) is reacted with a compound of the formula (8) in the presence of 1-50 mole %, preferably 2-10 mole %, of a palladium catalyst and a base such as triethylamine, sodium bicarbonate, or aqueous sodium carbonate and optionally lithium chloride in an organic solvent such as dimethylformamide, dimethoxyethane, acetonitrile, toluene, tetrahydrofuran, ethanol, or mixtures thereof, at elevated temperature, (e.g. 30-150°C) , preferably at the reflux temperature of the mixture. Suitably lΛ is halo for example iodo, bromo or chloro, preferably L 1 is a trifluoromethanesulphonate. Examples of palladium catalysts that can be used include: tetrakis(triphenylphosphine)palladium (Pd[PPh3]4), bis(triphenylphosphine)palladium dichloride (Pd[PPh3]2CI2) , [1,4-bis-(diphenylphosphine)butane]palladium dichloride (Pd(dppb)Cl 2 ), [1,3-bis- (diphenylphosphine)propane]palladium dichloride (Pd(dppp)Cl 2 ), [1,2-bis- (diphenylphosphine)ethane]palladium dichloride (Pd(dppe)Cl 2 ), is (tri-o-tolylphosphine) palladium diacetate or dichloride (Pd (totp) (OAc) 2 or Pd (totp) Cl 2 ) , or 1,1 -bis(diphenylphosphine)ferrocmopallad um diacetate or dichloride (PdCdppf] (OAc) 2 or Pd[dppf]Cl2) . By a chemical equivalent of a compound of the formula (8) is meant a reagent that can couple the Ar group onto the pyridyl ring of a compound of the formula (7) . For example aryl stannanes can be used, such as ArSnMe3 which can suitably be prepared by reacting a suitable aryl halide (such as ArBr or Arl) with a base such as t-butyl lithium followed by reaction with a trimethyl tin halide (e.g. Me3SnCl) . Alternatively the aryl halide can be reacted with Me3SnSnMe3 in the presence of a palladium catalyst as hereinbefore described to prepare a suitable aryl stannane. When R a is a group R° as hereinbefore defined and R b is a group R 1 as hereinbefore defined, reaction of a compound of the formula (7) with a compound of the formula (8) results directly in compounds of the formula (1) . An example of a precursor for R 1 is when R b is hydrogen. Examples of a precursor for R° is when R a is halo, such as chloro, which can be converted to another precursor OR 11 , such as methoxy or benzyloxy by reaction with either sodium methoxide or benzyl alcohol and a base such as potassium tert butoxide preferably in the presence of a crown ether such as 18-crown-6 or 15-crown-5. Preferably a compound of the formula (7) wherein R a is chloro, p is hydrogen and L 1 is trifluoromethane sulphonate is reacted with a compound of the formula (8) or a chemical equivalent thereof, followed by conversion of R a being chloro to R a being ORU to form a compound of the formula (2) . Such a compound can then be converted into a compound of the formula (1) as herein described. Other precursors for R 1 include CN, CHO or COMe. Reaction of a compound of the formula (7) wherein R b represents such a precursor and R a is OH or OR 11 with a compound of the formula (8) or a chemical equivalent thereof results in a compound of the formula (4) or a compound of the formula (6) wherein R 12 or R 13 is CN, CHO or COMe. Such compounds can be converted to compounds of the formula (1) as herein described. If desired a compound of the formula (1) wherein R~ is A0CO can be converted to the corresponding compound wherein R 1 is A0CO 2 R 9 by reaction with a compound R OH wherein R 9 is as hereinbefore defined. A compound of the formula (1) wherein R^ is OH can be converted to the corresponding compound where R^ is OR^ by reaction with R^L wherein R- is as hereinbefore defined an L 2 is a leaving group such as halo e.g. bromo, chloro, iodo. If desired a compound of the formula (1) wherein R 1 is P (Z) (OR 2 ) (OH) can be converted to the corresponding compound wherein R 1 is P(Z) (OR 2 ) (OR 1 ^) by reaction with a suitable O-protecting agent in standard manner. For example the compound can be reacted with a pivalolyloxymethyl halide. A compound of the formula (1) wherein R 1 is 5-tetrazole can be reacted with a suitable N-protecting agent in standard manner, for example with a pivalolyloxymethyl halide. A compound of the formula (1) wherein R^-RO is A!C0 2 is suitably prepared by heating a compound of the formula (1) wherein R 1 is A 1 C0 2 H and R- is OH with a dehydrating agent such as acetic anhydride, at an elevated temperature (e.g. 40 - 200°C) , preferably at the reflux temperature of the reaction mixture. A compound of the formula (1) wherein R 1 -R° is A 2 OCH 2 0 is suitably prepared by reacting a compound of the formula (1) wherein R 1 is A 2 OH and R° is OH with a dihalomethane such as diiodo- or dibromomethane in the presence of silver carbonate in an organic solvent such as dimethylformamide at an elevated temperature (e.g. 40 - 120°C) . A compound of the formula (2) is suitably prepared by reacting a compound of the formula (6) wherein R 13 is hydrogen with an O-methylating agent such as dimethylformamide dimethylacetal in dimethylformamide or trimethylphosphite at an elevated temperature (e.g. 40 - 120°C) or with iodomethane and silver carbonate in toluene or chloroform or with an O-benzylating agent such as benzyl bromide or chloride in the presence of a base such as potassium carbonate or sodium hydride. This method can also be used for converting compounds of the formula (6) into corresponding compounds of the formula (4) and compounds of the formula (7) where R a is hydroxy to corresponding compounds wherein R a is OR 11 . A compound of the formula (6) wherein R 13 is acetyl can also be prepared by reacting a compound of the formula (6) wherein R 13 is cyano with methyl lithium followed by aqueous acidic work up with for example hydrochloric acid. A compound of the formula (6) wherein R 13 is hydrogen can be prepared by reacting a compound of the formula (6) wherein R 1 is cyano with orthophosphoric acid at an elevated temperature, e.g. 50 - 200°C. A compound of the formula (6) wherein R 13 is cyano or acetyl and Ar is as hereinbefore defined can be suitably prepared by reaction of a compound of formula (4) wherein R 12 is cyano or acetyl and 11 and Ar are as hereinbefore defined with a demethylating agent or debenzylating agent as hereinbefore described. A compound of formula (4) wherein R 12 is cyano is suitably prepared by reacting the anion of a compound of formula (2) wherein Ar and R 11 are as hereinbefore defined with dimethylformamide with cooling (e.g. -80 to 10°C), followed by ambient temperature and aqueous work-up. The resulting compound of formula (4) wherein R^ 2 is carboxaldehyde is treated with hydroxylamine hydrochloride and sodium acetate in a suitable solvent such as ethanol or methanol at elevated temperature, e.g. 40-100°C, preferably at the reflux temperature of the reaction mixture followed by dehydrating the product obtained for example by heating with acetic anhydride. A compound of the formula (4) where R 12 is cyano is more suitably prepared by reacting a compound of the formula (9) wherein Ar and R 11 are as hereinbefore defined with a dimethyl carbamoyl halide such as the chloride folowed by reaction with trimethylsilylcyanide, conveniently at ambient temperature in a solvent such as dichloromethane. A compound of the formula (9) is suitably prepared by reacting a compound of the formula (2) with an oxidising agent such as metachloroperbenzoic acid in an organic solvent such as dichloromethane. A compound of the formula (6) wherein R^ 3 is P (0) (OR 2 ) 2 can be prepared by treating a compound of the formula (2) wherein RH is P (0) (0R 2 ) 2 with a strong base such as lithium diisopropylamide in an organic solvent such as tetrahydrofuran with cooling (e.g. -100-0°C) . A compound of the formula (2) wherein R 11 is P (0) (OR 2 ) 2 is suitably prepared by treating a compound of the formula (6) wherein R 13 is hydrogen with a compound of the formula (10) : L 3 P(0) (OR 2 )2 (10) wherein L 3 is a leaving group and R 2 is as hereinbefore defined with a base such as diisopropylethylamine. Suitably L 3 is halo, for example chloro or bro o. A compound of formula (2) wherein R 11 is P(0) (0R 2 ) 2 can also be prepared by treating a compound of the formula (6) wherein R 1 is hydrogen with a compound of the formula (11) : HP(O) (OR 2 ) 2 (ID wherein R 2 is as hereinbefore defined in the presence of an amine base such as triethylamine, and carbon tetrachloride. Alternatively, a compound of the formula (6) wherein R 13 is P(0) (OR 2 )2 is suitably prepared by treating a compound of the formula (6) wherein R 1 is hydrogen with a compound of the formula (10) in the presence of a strong base such as lithium diisopropylamide in an organic solvent such as tetrahydrofuran with cooling (e.g. -100-0°C) without isolation of the intermediate compound of the formula (2) wherein R 11 is (0) (0R 2 ) 2 . A compound of formula (6) wherein R 13 is hydrogen is suitably prepared by demethylating or debenzylating a compound of formula (2) as hereinbefore defined. Suitably a compound of formula (2) wherein OR 11 is methoxy is treated with boron tribromide in an organic solvent such as dichloromethane or toluene with cooling (e.g. -80 to 10°C) followed by ambient temperature and aqueous work-up. Or a compound of formula (2) is treated with sodium iodide and chlorotrimethylsilane at ambient or elevated temperature (e.g. 0-80°C) conveniently ambient temperature in a solvent such as acetonitrile or dichloromethane. A compound of the formula (6) wherein R 13 is P(0) (NHR 14 ) (OR 2 ) can be prepared by reaction of a compound of the formula (6) wherein R 13 is P(0) (OH) (OR 2 ) with carbon tetrachloride, triphenylphosphine and aniline or a Cι_4alkylamine in an organic solvent such as pyridine at ambient temperature or with cooling (e.g. -10 to 5°C) . Alternatively a compound of the formula (6) where R 13 is P(0) (OH) (OR 2 ) can be reacted with dimethylformamide and oxalyl chloride in an organic solvent such as a halo hydrocarbon e.g. dichloromethane at ambient temperature, followed by reaction with aniline or a Cι_4al ylamine preferably with cooling (-10 to 5°C) . Compounds of the formula (7) are known or can be prepared in standard manner for example from a compound of the formula (12) : wherein R a and L 1 are as hereinbefore defined using similar methods to those described for preparing compounds of the formula (1) . Thus, a compound of the formula (7) wherein R D is P(0) (OR 2 )2 can be prepared by reacting a compound of the formula (12) wherein R a is OH with a compound of the formula (10) or (11) in similar manner to the reaction of a compound of the formula (6) wherein R 13 is hydrogen with a compound of the formula (10) or (11) . If desired the group R a can then be converted to OR 11 as hereinbefore described. Similarly, a compound of the formula (12) where R a is OR 11 can be treated in the presence of a strong base with a compound of the formula (3) , a compound of the formula (5) , sulphuryl chloride, sulphur dioxide or dimethylformamide to prepare a compound of the formula (7) wherein P is CR 3 (OR )Cθ2R 9 , COC0 2 R 9 , SO3H, S0 2 H or CHO respectively in similar manner to the corresponding reaction with a compound of the formula (2) as hereinbefore described. Particularly suitable as a strong base is lithium tetramethyl piperidide. A compound of the formula (12) wherein R a is chloro and L 1 is trifluoromethanesulphonate is suitably prepared by reacting 3-chloro-5-hydroxy pyridine with trifluoromethane sulphonic anhydride in the presence of a suitable base, e.g. 4-N,N- dimethylaminopyridine in an organic solvent such as dichloromethane. A compound of the formula (8) is suitably prepared by reacting the organolithium or Grignard reagent, formed from a compound of the formula (13) : Ar-L 4 (13) wherein L 4 is bromo or iodo and Ar is as hereinbefore defined with a tri-Cι_ alk lborate such as tri ethyl, tri-isopropyl or tri-n-butyl borate in an organic solvent such as diethyl ether or tetrahydrofuran with cooling (e.g. - 80-10°C) . The Ar group in compounds of the formula (2) , (4) , (6) or (13) preferably (2) or (4) may be appropriately functionalised by methods of aromatic substitution known in the art. For example, a bromo group may be introduced into a suitably substituted phenyl ring (eg. disubstituted in the 2- and 4-positions by electron-donating groups such as Cι_galkoxy) by reaction with a brominating agent such as N—bromosuccini ide or bromine in a solvent such as dimethylformamide. Alternatively a nitro group can be introduced into a phenyl ring by reaction with a suitable nitrating agent, such as nitronium tetrafluoroborate. Such a group can be readily hydrogenated to an amino group which if desired can be converted to a NHCOR 7 group by reaction with LCOR 7 wherein L is a leaving group and R 7 is as hereinbefore defined. Suitable examples of the reagent LCOR include acid halides (L is halo eg. chloro or bromo) or acid anhydrides (L is OCOR 7 ) . Other suitable functionalisations include the introduction of an allyl group ortho to a hydroxy substituent on a phenyl ring by reaction with an allyl halide, eg. bromide, to form an allyloxy derivative which on heating undergoes a Claisen rearrangement to form an ortho allyl hydroxy derivative. The hydroxy group can in turn be functionalised, eg. by reaction with a Cι_galkyl halide to form a C^-galkoxy group. If desired, an allyl group can be converted to an E-1-propenyl group by reaction with a strong base, such as sodium methoxide. An E-1-propenyl group can be cleaved to a formyl group by reaction with an oxidising agent such as N-methylmorpholine-N-oxide in the presence of a catalyst suc as osmium tetroxide to form a l,2,dihydroxypropyl group whic on reaction with an oxidising agent such as sodium periodate forms the formyl group. Alternatively the E-1-propenyl grou can be converted directly to a formyl group by reaction with a mixture of osmium tetroxide and sodium periodate or by reaction with ozone. A formyl group can in turn be further functionalised, for example it can be converted to a hydroxymethyl group by reaction with a suitable reducing agent such as sodium borohydride, the hydroxymethyl group then being reacted further, eg. with a C^-galkyl halide to form a C^-galkoxymethyl group. Alternatively a formyl group can be reacted with a suitable Horner Wittig or Wittig reagent such as (R 15 0) 2 P(0)CH 2 C0 2 R 15 or Ph3P=CHC0 2 R 15 wherein R 15 is Cι_ alkyl to form a CH=CHC0 2 R 15 group which can be optionally hydrolysed to a -CH=CHC0 2 H group. A -CH=CHC0 2 R 15 group can be converted to a -CH=CHC0N(R 7 ) 2 group by reaction with an a ine HN(R ) 2 or a chemical equivalent thereof wherein R 7 is as hereinbefore defined. Alternatively a -CH=CHC0 2 H group can be converted to an acid halide, eg. the acid chloride by reaction with oxalyl chloride, which can then be reacted with an amine HN(R ) or a chemical equivalent thereof. An example of a chemical equivalent is ammonium hydroxide which will form a CH=CHCONH 2 group. Pharmaceutically acceptable base addition salts of the compounds of the formula (1) may be prepared by standard methods, for example by reacting a solution of the compound of the formula (1) with a solution of the base. The following biological test methods, data and Examples serve to illustrate this invention. Cyclic-AMP Protein Kinase (cA-PrK) Agonist Activity Type II cA-PrK was prepared from the cardiac muscle of a cow. The supernatant from a muscle homogenate (3 is of 10 mM potassium phosphate, 1 mM EDTA per g tissue) was applied to a column of DEAE-cellulose equilibrated with the homogenisation buffer and the type II cA-PrK was eluted with homogenisation buffer containing 350 mM sodium chloride (Rannels et al. / 1983, Methods Enzymol., 99, 55-62). Type II cA-PrK was assayed for phosphotransferase activity by incubating the enzyme at 30°C for 5 minutes with [γ- 2 P]-adenosine triphosphate and a suitable peptide substrate such as malantide (Malencik et al., 1983, Anal. Biochem., 132, 34-40). The reaction was terminated by the addition of hydrochloric acid and the [ 2 P]-phosphoρeptide quantified by spotting the reaction mixture onto phosphocellulose papers. The concentration of compound required to give 10% phosphotransferase activation is given as the ECio (|*M) • The compounds of Examples 1 to 3 had EC^Q values in the range 1.8 to 100 μM. Inhibition of Platelet Aggregation Human platelet-rich-plasma was separated from freshly drawn blood (in acid/citrate/dextrose) and treated with 100 μM acetylsalicylic acid for 15 minutes at 37°C. A washed platelet suspension was then prepared in a Hepes-isotonic saline buffer after a single centrifugation step and adjusted to a concentration of 1.5xl0 8 cells/ml. Aliquots of this suspension were pre-incubated with compounds for 5 minutes at 37°C, then challenged with 1.0 μM U46619. The extent of aggregation after 2 minutes were expressed as a percentage of control and results obtained are expressed as an IC50 (concentration to cause 50% inhibition of platelet aggregation, μM) . The compounds of Examples 1 to 3 had IC50 values in the range 6 to 109 μM. Inhibition of Spontaneous Contraction in Guinea-Pig Colon Segments of isolated guinea-pig colon (2 cm) were suspended under 2 g tension in standard organ baths containing Krebs solution. The tissues were connected at the free end to isometric transducers which allow recording and display of developed tension on chart recorders. On-line computer capture and analysis was used to quantify the effects of test compounds on spontaneous contractions. Inhibitory responses were calculated as % maximum inhibition of spontaneous contraction distance over 3 consecutive pre and post dose 2 minute readings. The concentration of compound which caused 50% inhibition of the spontaneous contraction is given as the EC 50 (μM) . Bronchodilatation - In vitro Spiral strips of guinea-pig trachea were suspended in standard organ baths containing Krebs solution. The tissues were connected at the free end to isometric transducers which allow recording and display of developed tension on chart recorders. Tension was allowed to develop spontaneously and concentrations of test compounds added in a cumulative, fashion. The concentration of compound which caused 50% inhibition of the spontaneously developed tension is given as the IC50 (μM) . The compound of Example 1 had a IC50 value of 100 μM. Measurement of cardiac muscle relaxation time in rabbit ventricle Papillary muscles from the right ventricle of female Albino New Zealand rabbits are mounted in standard organ baths containing oxygenated Krebs solution. One end of the muscle is connected to an isometric transducer which allowed recording of contractile force and its first derivative on chart recorders. Test compounds are added to the bath in a cumulative manner. Relaxation time is calculated as the time taken from peak tension to the end of the contraction. Compounds which cause a decrease in the relaxation time indicate a positive lusitropic effect of use in the treatment of cardiovascular diseases where there is a component of diastolic failure such as congestive heart failure, angina, hypertension and cardiomyopathy. Example 1 Ethyl [5-(2-Naphthyl)-3-hydroxy-2-pyridyl]phosphonate (a) To an ice cooled solution of 3-chloro-5-hydroxypyridine (4.95g) and 4-N,N-dimethylaminopyridine (14g) in dichloromethane (300mls) , trifluoromethanesulphonic anhydride (lOg) was added over 30 minutes. When the addition was complete the mixture was stirred for a further 2 hours and poured into 1M hydrochloric acid (300ml) . The organic phase was separated, washed with water (2 x 100ml) , dried (MgSθ ) and solvent removed at reduced pressure to give 3-chloro-5- trifluoromethanesulphonyloxypyridine (8.9g) as an oil that solidified on standing. !H NMR 5 (CDCI3) 7.69(m, 1H) , 8.52 (m,lH) and 8.65 (m, 1H) . (b) From 2-naphthylboronic acid (2.33g) and 3-chloro-5- trifluoromethanesulphonyloxypyridine (3.4g), 3-chloro-5- (2- naphthyl)pyridine (2.5g) was prepared according to the method of A. Huth, I. Beetz and I. Schumann, Tetrahedron, 1989, 45, 6679. H NMR δ (CDCI3) 7.52-7.57 (m, 2H) , 7.68(dd,lH), 7.84- 8.04(m,5H), 8.58(m,lH) and 8.85 (d, 1H) . (c) A mixture of 3-chloro-5- (2-naphthyl)pyridine (2.0g) and sodium methoxide in dimethylformamide (50ml) was heated at 130°C for 3.5 hours. The mixture was poured onto ice, stirred vigorously for one hour and extracted with diethyl ether (200ml) . The ether extract was washed with water (4 x 100ml) , dried (MgSθ > and solvent removed at reduced pressure. The residue was column chromatographed (silica gel, dichloromethane eluant) to give 3-methoxy-5- (2- naphthyl)pyridine (1.2g) . 1.H NMR δ (CDCI3) 4.12(s,3H), 7.51- 7.62(m,3H), 7.82-8.0 (m, 5H) , 8.19(dd,lH) and 8.53 (s, 1H) . (d) A solution of 3-methoxy-5- (2-naphthyl) pyridine (2.07g) in a mixture of acetic acid/hydrobromic acid (250ml, 2:3) was boiled for 65 hours. After cooling to room temperature solvent was removed at reduced pressure and the residue triturated with water (100ml) to give 3-hydroxy-5- (2- naphthyl)pyridine (1.75g) !H NMR δ (DMSO-dg) 7.50-7.58 (m,3H) , 7.86(d,lH), 7.95-8.08(m,3H), 8.17(d,lH), 8.28(s,lH), 8.52(d,1H) and 10.15(br.s,1H) . ' (e) To a solution of 3-hydroxy-5-(2-naphthyl)pyridine (1.75g) in tetrahydrofuran (30ml) , lithium diisopropylamide (prepared from n-butyl lithium 3.8mls of 2.5M solution in hexane and diisopropylamine 0.81g) was added at -78°C. When the addition was complete the reaction mixture was warmed to room temperature stirred for 90 minutes, recooled to -78°C and treated with diethyl chlorophosphate (1.38g) . The mixture was warmed to room temperature stirred for 15 minutes recooled to -78°C and treated with additional lithium diisopropylamide (from n-butyl lithium 3.8mls Of 2.5M in hexane and diisopropylamine 0.81g) . After stirring at -78°C for 15 minutes and at room temperature for 20 minutes the reaction mixture was poured into a mixture of ice (lOOg) and cone, hydrochloric acid (15ml) and stirred overnight. Tetrahydrofuran was removed at reduced pressure and the aqueous residue extracted with dichloromethane (2 x 100ml) . The combined organic extracts were washed with water (2 x 100ml) dried (MgSθ4) and solvent removed at reduced pressure. The residual oil was column chromatographed (silica gel, dichloromethane followed by diethyl ether followed by ethyl acetate/ethanol 4:1 eluant) to give diethyl [3-hydroxy-5-(2- naphthyl)-2-pyridyl]phosphonate (1.86g). --R NMR δ (CDCI3) 1.39(t,6H), 4.15-4.37(m,4H), 7.53-7.62(m,3H) , 7.71(dd,lH), 7.87-7.95(m,3H) , 8.08(s,lH) and 8.69(d,1H) . e) A mixture of diethyl [3-hydroxy-5-(2-naphthyl)-2- pyridyl]phosphonate (0.2g) and sodium hydroxide (0.5g) in water/ethanol (11ml, 10:1) was boiled for 12 hours. The solvent was removed at reduced pressure, the residue dissolved in water (3ml) and acidified with cone, hydrochloric acid (15ml) . The precipitated material was collected by filtration and recrystallised from ethanol to give the title compound (0.15g) m.p. 252-254°C. 1H NMR δ (DMSO-dg) 1.15(t,3H), 3.83-3.96(m,2H) , 7.56-7.62(m,2H) , 7.98- 8.11(m,3H), 8.19(m,lH), 8.50(s,lH) and 8.73(s,1H) . Eacample 2 5-(2, -Dipropoxyphenyl)-2-(5-tetrazolyl)pyridin-3-ol a) A mixture of 4-bromoresorcinol (25g) potassium carbonate and iodopropane in dimethylformamide was heated in dimethylformamide at 90° for 18 hours. Solvent was removed at reduced pressure the residue triturated with diethyl ether, filtered, the filtrate adsorbed onto silica gel and column chromatographed (silica gel, petroleum ether/diethyl ether 9:1 eluant) to give l-bromo-2, 4-dipropoxybenzene (llg) . ^H NMR δ (CDC1 3 ) 1.03(t,3H), 1.06(t,3H), 1.71-1.94 (m, 4H) , 3.89(q,2H), 3.92(q,2H), 6.37(dd,lH), 6.46(d,lH) and 7.37 (d, 1H) . b) From 2, 4-dipropoxyphenyl lithium [prepared by addition of l-bromo-2, 4-dipropoxy-benzene (11.Og) to tert-butyl lithium (48 mis of 1.7M in pentane], (2, 4-dipropoxyphenyl)boronic acid (6.1g) was prepared according to the method of W.J.Thompson and J.Gaudino J. Org. Chem., 1984, 49, 5237. --R NMR δ (CDCI3) 1.14(t,3H), 1.16(t,3H), 1.84-2.04 (m, 4H) , 4.06(q,2H), 4.19(q,2H), 6.55 (d,lH), 6.66(dd,lH) and 7.85(d,lH) . c) From (2, -dipropoxyphenyl)boronic acid (5.0g) and 3- chloro-5-trifluoromethanesulphonyloxypyridine (5.5g), 3- chloro-5- (2, 4-dipropoxyphenyl)pyridine (6.47g) was prepared according to the method of Example 1(b) . 1 H NMR δ (CDCI3) 0.99(t,3H), 1.06(t,3H), 1.72-1.89 (m, 4H) , 3.93(t,2H), 3.96(q,2H), 6.55-6.59 (m,2H) , 7.26(d,lH), 7.87(m,lH), 8.45 (d,lH) and 8.62 (d,lH) . d) 3-Chloro-5- (2, 4-dipropoxyphenyl)pyridine (3.9g), benzyl alcohol (20.Og), potassium tertbutoxide (4.0g) and 18-crown-β (O.lg) were combined in N-methylpyrrolidinone (20mls) and heated at 130°C for 48 hours. The mixture was poured into a mixture of ice (lOOg) and cone, hydrochloric acid (10ml) and extracted with dichloromethane (3 x 100ml) . The combined organic extracts were dried (MgSθ4) and solvent removed at reduced pressure. The residue was column chromatographed (silica gel, petroleum ether/diethyl ether 4:1 eluant) to give 3-benzyloxy-5-(2,4-dipropoxyphenyl)pyridine (1.6g). 1 H NMR δ (CDCI3) 0.97(t,3H), 1.06(t,3H), 1.65-1.91(m,4H) , 3.91(t,2H), 3.95(t,2H), 5.13(s,2H), 6.51-6.57 (m,2H) , 7.26- 7.49(m,7H), 8.27(d,lH) and 8.37 (d,1H) . e) 3-Chloroperbenzoic acid (2.0g) was added to a solution of 3-benzyloxy-5-(2,4-dipropoxyρhenyl)pyridine (1.6g) and the mixture was stirred for 3 hours. Solvent was removed at reduced pressure and the residue column chromatographed (silica gel, dichloromethane/petroleum etherl:! eluant) to give 3-benzyloxy-5-(2,4-dipropoxyphenyl)pyridine-N-oxide (1.6g). !H NMR δ (CDCI3) 0.99(t,3H), 1.06(t,3H), 1.74- 1.87(m,4H), 3.93(t,2H), 3.95(t,2H), 5.09(s,2H), 6.52- 6.59(m,2H), 7.16-7.20(m,2H) , 7.40(s,5H), 7.96(s,lH) and 8.13(S,1H) . f) From 3-benzyloxy-5-(2,4-diρropoxyphenyl)pyridine-N-oxide (1.6g) , 3-benzyloxy-2-cyano-5-(2,4-dipropoxyphenyl)pyridine (0.8g) was prepared according to the method of W. K. Fife, Heterocycles, 1984, 22, 93. 1_H NMR δ (CDCI3) 0.97 (t,3H), 1.06(t,3H), 1.68-1.91(m,4H), 3.92(t,2H), 3.96(t,2H), 5.25(s,2H), 6.55(s,lH), 6.56(dd,lH), 7.20(d,lH), 7.33- 7.46(m,5H), 7.59(d,lH) and 8.44(d,1H) . g) A mixture of 3-benzyloxy-2-cyano-5-(2,4- dipropoxyphenyl)pyridine (0.8g), sodium azide (0.54g) and ammonium chloride (l.Og) were heated together in N- ethylpyrrolidinone (15ml) at 190°C for 6 hours. Solvent was removed at reduced pressure and the residue triturated with water. The crude product was collected by filtration and chromatographed (C 8 reverse phase silica gel, acetonitrile/0.1% aqueous trifluoroacetie acid 3:2 eluant) to give the title compound (0.13g) m.p. 179-180°C. H NMR δ (DMSO-dg) 0.95(t,3H) 1.00(t,3H), 1.67-1.84(m,4H) , 3.99(t,4H) 6.58-6.68(m,2H), 7.47(d,lH), 7.64(s,lH) and 8.44(s,1H) . Example 3 5-(4-Methoacy-3-propoxyphenyl)-3-(5-tetrazolyl)pyridin-3-ol a) From 3-hydroxy-4-methoxy-nitrobenzene (25g) , 4-methoxy-l- nitro-3-propoxybenzene (31g) was prepared according to the method of Example 2(a) . 1 H NMR δ (CDCI3) 1.07 (t, 3H) , 1.82- 1.97(m,2H), 3.97(s,3H), 4.05(t,2H), 6.91(d,lH), 7.74(d,lH) and 7.90 (dd, 1H) . (b) A solution of 4-methoxy-l-nitro-3-propoxybenzene (20g) in acetic acid (150ml) containing 10% palladium on charcoal (2g) was heated at 80°C under an atmosphere of hydrogen (60p.s.i) with shaking for 4 hours. The reaction mixture was filtered under nitrogen into 50% sulphuric acid (300ml) cooled to 0°C and treated with an aqueous solution of sodium nitrite (6.9g in 20ml water) at such a rate that the temperature did not rise above 5°C. When the addition was complete the mixture was stirred for a further 2 hours at 0°C and then poured into a solution of potassium iodide (200g) iodine (40g) and urea (lg) in water (300ml) . Dichloromethane (300ml) was added and the mixture stirred vigorously at room temperature until gas evolution ceased (3 hours. Sodium metabisulphite (20g) was added, the organic phase was separated washed with water (2 x 100ml), dried (MgSθ ) and solvent removed at reduced pressure. The residue was column chromatographed (silica gel petroleum ether/dichloromethane 1:1 eluant) to give l-iodo-4- methoxy-3-propoxybenzene (17g) ~R NMR δ (CDCI3) 1.03(t,3H), 1.77-1.95 (m,2H) , 3.83(s,3H), 3.93(t,2H), 6.61(d,lH), 7.11 (d,lH) and 7.19 (dd, 1H) . (c) From l-iodo-4-methoxy-3-propoxybenzene (16.9g), (4- methoxy-3-propoxyphenyl)boronic acid (lO.Og) was prepared according to the method of Example 2 (b) . 1 H NMR δ (DMSO-dg) 0.98(t,3H), 1.65-1.79(m,2H), 3.76(s,3H), 3.89(t,2H), 6.91(d,lH), 7.32-7.37 (m,2H) and 7.86 (br.s,2H) . (d) From (4-methoxy-3-propoxyphenyl)boronic acid (10.0g) and 3-chloro-5-trifluoromethanesulphonyloxypyridine (12.6g), 3- chloro-5-(4-methoxy-3-propoxyphenyl)pyridine (11.Og) was prepared according to the method of Example 1 (b) . 1 H NMR δ (CDC1 3 ) 1.07(t,3H), 1.83-1.99(m,2H) , 3.92(s,3H), 4.05(t,2H), 6.97(d,lH), 7.06(d,lH), 7.11(dd,lH), 7.81 (m,lH), 8.50 (d,lH) and 8.67(d,1H) . (e) From 3-chloro-5-(4-methoxy-3-propoxyphenyl)pyridine (10.Og}, 3-benzyloxy-5-(4-methoxy-3-propoxyphenyl)pyridine was prepared according to the method of Example 2(d) . The crude material was treated with 3-chloroperbenzoic acid (10.Og) according to the method of Example 2(e) to give 3- benzyloxy-5-(4-methoxy-3-propoxyphenyl)pyridine-N-oxide (4.0g) --E NMR 1.06(t,3H) , 1.82-1.97(m,2H) , 3.91(s,3H), 4.00(t,2H), 5.13(s,2H), 6.88-7.09(m,4H) , 7.42(s,5H), 7.98(s,lH) and 8.14(s,lH) . (f) From 3-benzyloxy-5-(4-methoxy-3-propoxyphenylpyridine-N- oxide (3.8g), 3-benzyloxy-2-cyano-5-(4-methoxy-3- propoxyphenyl)pyridine (2.3g) was prepared according to the method of Example 2(f) . NMR δ (CDCI3) 1.08 (t,3H), 1.83- 1.98 (m,2H), 3.98 (s,3H), 4.01(t,2H), 6.94-6.98 ( ,2H) , 7.07(dd,lH), 7.38-7.50(m, 6H) and 8.45(d,1H) . (g) From 3-benzyloxy-2-cyano-5-(4-methoxy-3- propoxyphenyl)pyridine (1.55g) , the title compound (0.6g) m.p. 229-230°C after reverse phase chromatography (water then 1% aqueous trifluoroacetie acid/acetonitrile 2:3 eluant) was prepared according to the method of Example 2(g) . --K NMR 1.01(t,3H), 1.70-1.81(m,2H), 3.83(s,3H), 4.05(t,2H), 7.10(d,lH), 7.30-7.38(m,2H), 7.77(s,lH) and 8.63(lH). . Example 4 Pharmaceutical compositions for oral administration are prepared by combining the following : % w/w Ethyl [5-(2-Naphthyl)-3- hydroxy-2-pyridyl]phosphonate 0.5 3.0 7.14 2% w/w Soya lecithin in soya bean oil 90.45 88.2 84.41 Hydrogenated vegetable shortening and beeswax 9.05 8.8 8.45 The formulations are then filled into individual soft gelatin capsules. Example 5 A pharmaceutical composition for parenteral administration is prepared by dissolving the title compound of Example 2 (0.02 g) in polyethylene glycol 300 (25 ml) with heating. This solution is then diluted with water for injections Ph. Eur. (to 100 ml) . The solution is then sterilised by filtration through a 0.22 micron membrane filter and sealed in sterile containers.

Claims: Claims 1. A compound of the formula (1) : or a pharmaceutically acceptable salt thereof, wherein : R- is OH or a bioprecursor thereof, R 1 is °Cθ2H, P(Z) (OH) (OR 2 .) , S0 2 H, S0 3 H or 5-tetrazolyl or a bioprecursor thereof, A° is CH 2r CHF, CF 2 , CR 3 (OR 4 ) , CO or C(0R 5 ) (OR 6 ), R 2 is phenyl, C3_5cycloalkyl, C3_5cycloalkylCι_4alkyl, or C _βalkyl optionally substituted by Cι_4alkoxy, R 3 is H, methyl or ethyl, R 4 is H or Cι_3alkyl, R5 and R 6 are each C _3alkyl or together form a 1,2- ethanediyl group or 1,3-propanediyl group, Z is 0 or S, and Ar is phenyl optionally substituted by one to three groups independently selected from C _galkyl, C2-galkenyl, C ] __galkoxy, C3_galkenyloxy, C3_gcycloalkyl, C3_gcycloalkoxy, Cι_galkylthio, phenyl, phenylthio, benzyloxy, C^-gpolyfluoroalkyl, C _gpolyfluoroalkoxy, halo, N(R 7 )2 or NHCOR 7 wherein R 7 is H or C^-galkyl, or -X(CH2) n Y- attached to adjacent carbon atoms of the phenyl ring wherein X and Y are independently CH2 or 0 and n is 1 to 3, wherein said C^-galkyl, C 2 _galkenyl or C^-galkoxy groups can be independently substituted by OH, Cι_galkoxy, C3_gcycloalkyl, N(R 7 ) , C0 2 R 7 or CON(R 7 ) 2 ; or Ar is 1-naphthyl optionally substituted in the 4-position by hydroxy or C^-galkoxy, 2-naphthyl optionally substituted in the 1-position by hydroxy or C^-galkoxy, 3_phenanthryl, 9-phenanthryl, 2-quinolinyl, 4-quinolinyl, 3-thianaphthenyl or 2-benzofuranyl. 2. A compound according to claim 1 wherein R- is Aθcθ 2 H or A^C0 2 R 9 in which R 9 is an ester-forming group. 3. A compound according to claim 1 wherein R^ is P(Z) (OH) (OR 2 ) or P(Z) (OR 2 ) 2 . 4. A compound according to claim 1 wherein R! is S0 2 H, SO3H or 5-tetrazolyl. 5. A compound according to claim 1 wherein Rl and R^ are linked together such that R^—R 0 is A 1 C0 2 in which A 1 is CH 2 , CHF, CF 2 , CR 3 (OR 4 ), CO or C(OR 5 ) (OR 6 ). 6. A compound according to claim 1 wherein R-- and R^ are linked together such that R 1 -R° is A 2 OCH 2 0 in which A 2 is P(Z) (OR 2 ) or CR 3 (C0 R 9 ) and R 9 is an ester-forming group. 7. A compound according to claim 1 which is : ethyl [5-(2-naphthyl)-3-hydroxy-2-pyridyl]phosphonate, 5-(2,4-dipropoxyphenyl)-2-(5-tetrazolyl)pyridin-3-ol, or 5- (4-methoxy-3-propoxyphenyl)-3- (5-tetrazolyl)pyridin-3-ol, or a pharmaceutically acceptable salt thereof. 8. A compound according to any one of claims 1 to 7 for use as a medicament. 9. A pharmaceutical composition which comprises a compound according to any one of claims 1 to 7 and a pharmaceutically acceptable carrier. 10 A process for preparing a compound of the formula (1) as defined in claim 1 or a pharmaceutically acceptable salt thereof which process comprises : a) for compounds wherein R 1 is A^C0 2 H or A0CO 2 R and : i) A 0 is CR 3 (OR 4 ) , reacting in the presence of a strong base a compound of the formula (2) : wherein RH is an O-protecting group and Ar is as defined in claim 1, with a compound of the formula (3) : R 3 COC02R 9 (3) wherein R 3 is as defined in claim 1 and R 9 is an ester- forming group to form a compound of the formula (4) : (4) wherein R 12 is CR 3 (OH)C0 2 R 9 and R 3 , R 9 , R 11 , and Ar are as hereinbefore defined and thereafter optionally reacting with a C__3alkylating agent to form the corresponding compound wherein R 12 is CR 3 (OC _3alkyl)C0 2 R 9 , ii) A 0 is CO, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with a compound of the formula (5) : R 9 0 2 CC0 2 R 9 (5) wherein R 9 is as hereinbefore defined to form a compound of the formula (4) wherein R 12 is C0C0 2 R 9 and R 9 , R 11 and Ar are as hereinbefore defined, iii) A 0 is CH(OH) , reacting a compound of the formula (4) wherein R 12 is COC0 2 R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a reducing agent to form the corresponding compound wherein R 12 is CH(OH)C0 2 R 9 , iv) A 0 is CH , reacting a compound of the formula (4) wherein R^- 2 is C0C0 2 H or COCO2R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a suitable reducing agent to form the corresponding compound wherein R 12 is CH2CO2H, v) A° is C(OR 5 ) (OR 6 ) , reacting a compound of the formula (4) wherein R 12 is COCO2R 9 and R 9 , RH, and Ar are as hereinbefore defined with a Cl-3alcohol, 1,2-ethanediol or 1, 3-propanediol to form the corresponding compound wherein R^ 2 is C(OR^) (OR 6 )C02R 9 , vi) A 0 is CF2, reacting a compound of the formula (4) wherein R^ 2 is COCO2 9 and R 9 , R-^, and Ar are as hereinbefore defined with a fluorinating agent to form the corresponding compound wherein R 11 is CF 2 C0 2 R 9 , or vii) A 0 is CHF, reacting a compound of the formula (4) wherein R^ 2 is CH(0H)C02R 9 and R 9 , R 11 , and Ar are as hereinbefore defined with a fluorinating agent to form the corresponding compound wherein R 12 is CHFCO2R 9 , and thereafter optionally : 0 converting the group O .H into OH 0 converting the group A°Cθ2R 9 into A°C0 2 H; or b) for compounds wherein R 1 is CH 2 C0 2 H, converting a compound of the formula (6) : wherein R 13 is acetyl and Ar is as hereinbefore defined into the corresponding compound wherein R^ 3 is CH C0 2 H; or c) for compounds wherein R 1 is CH(OR 4 )CO2H reacting a compound of the formula (4) wherein R12 is -CH(OH)CN with a Cχ_3alkylating agent and/or converting the group CN into C0 2 H, and optionally converting the group OR 11 into OH; or d) for compounds wherein R 1 is P(0) (OH) (OR 2 ), hydrolysing a compound of the formula (6) wherein R 13 is P(0) (0R ) 2/ R 2 is as defined in claim 1 and Ar is as hereinbefore defined; or e) for compounds wherein R 1 is P(S) (OH) (OR 2 ), converting a compound of the formula (6) wherein R 13 is (0) (NHR 14 ) (OR 2 ) and R 14 is phenyl or Cχ_ alkyl and Ar is as hereinbefore defined into the corresponding compound wherein R^ 3 is P(S) (OH) (OR 2 ) ; or f) for compounds where R-*- is SO3H, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with sulphury1 chloride or a chemical equivalent thereof and optionally converting the group ORH into OH; or g) for compounds wherein R 1 is S0 2 H, reacting in the presence of a strong base a compound of the formula (2) as hereinbefore defined with sulphur dioxide and optionally converting the group OR 11 into OH; or h) for compounds wherein R- is 5-tetrazolyl, reacting a compound of the formula (4) wherein R^ 2 is cyano or a compound of the formula (6) wherein R^- 3 is cyano with an azide salt and thereafter if necessary converting the group OR 11 into OH; or i) for compounds wherein R 1 is as defined for compounds of the formula (1) reacting in the presence of a palladium catalyst a compound of the formula (7) : wherein p is a group R^ as defined in claim 1 or a precursor thereof and R a is a group R^ or as defined in claim 1 or a precursor thereof and L 1 is a leaving group with a compound of the formula (8) : ArB(OH) (8) or a chemical equivalent .thereof wherein Ar is as hereinbefore defined and then, if necessary, converting a precursor of R 1 into R 1 and/or converting a precursor of R° into OH, and optionally thereafter : ° forming a bioprecursor of R^ and/or Rl - forming a pharmaceutically acceptable salt.

Inventors: MURRAY KENNETH JOHN, PORTER RODERICK ALAN, PRAIN HUNTER DOUGLAS, WARRINGTON BRIAN HERBERT, MURRAY, KENNETH, JOHN, PORTER, RODERICK, ALAN, PRAIN, HUNTER, DOUGLAS, WARRINGTON, BRIAN, HERBERT
Applicants: SMITHKLINE BEECHAM PLC
Application year: 1992
Main classification: C07F9
IPC codes: A61K31, A61P7, A61P9, A61P11, A61P43, C07D213, C07D401, C07D405, C07D409, C07F9