4-AMINO-3-ACYLQUINOLINE DERIVATIVES AND THEIR USE AS INHIBITORS OF GASTRIC SECRETION

Abstract: Compounds of structure (I) in which R¹ is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, C₁₋₆alkoxyC₁₋₆-alkyl, C₃₋₆cycloalkyl, C₃₋₆cycloalkylC₁₋₆alkyl, phenylC₁₋₆alkyl, the phenyl group being optionally substituted; R² is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; m is 1 to 3; R³ is hydrogen, C₁₋₆alkyl, phenyl, C₁₋₆alkoxy, C₁₋₆alkylthio, C₁₋₆alkanoyl, amino, C₁₋₆alkylamino, di-C₁₋₆alkylamino, halogen, trifluoromethyl or cyano; n is 1 or 2; and R⁴O- is hydroxy or a bioprecursor of a hydroxy group, processes for their preparation, intermediates useful in their preparation, pharmaceutical compositions containing them and their use in therapy as gastric acid secretion inhibitors.

Description: The present invention relates to novel substituted quinoline derivatives, processes for their preparation, intermediates useful in their preparation, pharmaceutical compositions containing them and their use in therapy. Substituted quinoline derivatives having activity as inhibitors of gastric acid secretion are known in the art. In particular, US 4343804 and EP 259174-A disclose a series of 4-phenylaminoquinoline compounds in which the phenyl ring is optionally substituted by a range of substituents. Similar compounds are disclosed in US 3470186 and are said to have utility as diuretic and anti-depressant agents. It has now been found that a novel class of compounds falling within the above broad disclosures, namely 4-phenylaminoquinolines in which the phenyl ring is substituted by a 4-hydroxy group are particularly potent inhibitors of gastric acid secretion. Accordingly, the present invention provides, in a first aspect, a compound of structure (I) : in which R¹ is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, C₁₋₆alkoxyC₁₋₆-alkyl, C₃₋₆cycloalkyl, C₃₋₆cycloalkylC₁₋₆alkyl, phenylC₁₋₆alkyl, the phenyl group being optionally substituted by 1-3 substituents selected from C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; R² is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; m is 1 to 3; R³ is hydrogen, C₁₋₆alkyl, phenyl, C₁₋₆alkoxy, C₁₋₆alkylthio, C₁₋₆alkanoyl, amino, C₁₋₆alkylamino, di-C₁₋₆alkylamino, halogen, trifluoromethyl or cyano; n is 1 or 2; and R⁴O- is hydroxy or a bioprecursor of a hydroxy group chosen from C₁₋₆ alkanoyloxy, aryl C₁₋₆alkanoyloxy, arylsulphonyloxy or alkylsulphonyloxy; or a salt thereof. Suitably, R¹ is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, C₁₋₆alkoxyC₁₋₆alkyl, C₃₋₆cycloalkyl, C₃₋₆cycloalkyl-C₁₋₆alkyl, phenylC₁₋₆alkyl, the phenyl group being optionally substituted. Preferably R¹ is hydrogen, C₁₋₆alkyl or C₁₋₆alkoxy. Most preferably R¹ is C₁₋₆alkyl, in particular ethyl, n-propyl or i-propyl. Suitably m is 1 to 3; preferably m is 1 or 2; most preferably m is 1. Suitably R² is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl. Preferably R² is hydrogen, C₁₋₆alkyl or C₁₋₆alkoxy; most preferably R² is C₁₋₆alkyl or C₁₋₆alkoxy in particular methyl or methoxy. Preferably at least one group R² is in the 2-position of the phenyl ring (i.e. ortho to the bond joining the ring to the nitrogen atom); most preferably m is 1 and R² is a C₁₋₆ alkyl in the 2-position of the phenyl ring. Suitably, n is 1 or 2, preferably n is 1; preferably R³ is in the 8-position of the quinoline ring. Suitably R³ is hydrogen, C₁₋₆alkyl, phenyl, C₁₋₆alkoxy, C₁₋₆alkylthio, C₁₋₄alkanoyl, amino, C₁₋₆alkylamino, diC₁₋₆alkylamino, halogen, trifluoromethyl or cyano. Preferably R³ is hydrogen, C₁₋₆alkyl or C₁₋₆alkoxy, for example, methyl or methoxy; most preferably n is 1 and R³ is a C₁₋₆alkoxy in the 8-position of the quinoline ring. Suitably R⁴0- is a bioprecursor of a hydroxy group chosen from C₁₋₆alkanoyloxy (for example OCOCH₃ or OCOC(CH₃)₃), arylC₁₋₆alkanoyloxy (for example OCOCH₂Ph), arylsulphonyloxy (for example toluenesulphonyloxy) or alkylsulphonyloxy (for example methanesulphonyloxy) that is to say a group which is converted to a hydroxy group on administration to a subject; most preferably R⁴0- is hydroxy. C₁₋₆alkyl groups (either alone or as part of another group) can be straight or branched. Phenyl C₁₋₆alkyl groups include for example the benzyl, phenylethyl, phenylpropyl and phenylbutyl groups, and such groups in which the alkyl position thereof is branched e.g. 1-methylbenzyl. Substituted phenyl C₁₋₆alkyl groups R¹ include phenyl groups substituted by 1 to 3 substituents R² as hereinbefore described. It will be appreciated that compounds of structure (I) in which one or more of R¹ to R³ is a C₃₋₆alkyl group (either alone or as part of another group for example a benzyl or phenethyl group) may contain an asymmetric centre due to the presence of the C₃₋₆alkyl group. Such compounds will exist as two (or more) optical isomers (enantiomers). Both the pure enantiomers, racemic mixtures (50% or each enantiomer) and unequal mixtures of the two are included within the scope of the present invention. Further, all diastereomeric forms possible (pure enantiomers and mixtures thereof) are within the scope of the invention. Compounds of structure (I) can form pharmaceutically acceptable acid addition salts with suitable organic and inorganic acids the nature of which will be apparent to persons skilled in the art. For example, pharmaceutically acceptable salts can be formed by reaction with hydrochloric, sulphuric, or phosphoric acids; aliphatic, aromatic or heterocyclic sulphonic acids or carboxylic acids such as for example, citric, maleic or fumaric acids. In a further aspect, the present invention provides a process for the preparation of a compound of structure (I) which comprises (a) reaction of a compound of structure (II) with a compound of structure (III) : in which R¹, R², R³, n and m are as described for structure (I), R⁵ is hydrogen or a protecting group and X is a group displaceable by an amine; (b) reduction of a compound of structure (IV) : in which R¹, R², R³ n and m are as described for structure (I), R⁵ is a hydrogen or a protecting group and R⁶ is hydrogen or a nitrogen protecting group; (c) for compounds of structure (I) in which R¹ is other than C₁₋₆alkoxy, oxidation of a compound of structure (V) : in which R², R³, n and m are as described for structure (I), R¹′ is a group R¹ other than C₁₋₆alkoxy and R⁵ and R⁶ are as described for structure (IV); and thereafter if desired, removing any protecting groups; converting a group R¹ into another group R¹; forming a salt. Suitable groups X displaceable by an amine, include for example, halo moieties, aryl or alkylsulphonates, for example, toluene-p-sulphonate or methane sulphonate, alkylthio, alkylsulphonyl, alkylsulphinyl, alkoxy or aryloxy groups. Preferably X is halo, for example, chloro or bromo, or an aryloxy moiety such as phenoxy. Suitable hydroxy protecting groups R⁵ and nitrogen protecting groups R⁶ will be apparent to those skilled in the art for example as decribed in "Protective Groups in Organic Synthesis" T.W. Greene, 1981 (Wiley). The reaction between compounds of structure (II) and compounds of structure (III) is carried out in an organic solvent at a temperature of between ambient and reflux temperature of the solvent used. Suitable solvents include, for example, tetrahydrofuran, dioxan or anisole. Preferably the reaction is carried out at reflux temperature in dioxan as a solvent. The reduction of a compound of structure (IV) is carried out by for example hydrogenation, over a noble metal catalyst in a suitable solvent. Suitably the reaction is carried out over a palladium on carbon catalyst in ethanol as a solvent. The compounds of structure (IV) can be prepared from the corresponding compounds of structure (VI) : in which R¹, R², R³, R⁵, R⁶, n and m are as hereinbefore described, by reaction with, for example, phosphorus oxychloride. The oxidation of a compound of structure (V) is carried out in a suitable colvent in the presence of an oxidising agent. Suitable oxidising agents include, for example, manganese dioxide or chromium trioxide. Suitable interconversions of groups R¹ will be apparent to those skilled in the art, for example compounds of structure (I) in which R¹ is C₂₋₆alkyl, C₃₋₆cycloalkylC₂₋₆alkyl or optionally substituted phenylC₂₋₆alkyl can be prepared by alkylation of the following compounds of structure (IA) : in which R², R³, n and m are as described for structure (I) and R⁵ and R⁶ are as described for structure (IV). The alkylation of compounds of structure (IA) is carried out in the presence of an alkylating agent in a suitable organic solvent at a temperature of between ambient and reflux temperature of the solvent used in the presence of a strong base. Suitable alkylating agents include, for example alkyl or aralkyl halides such as methyl or benzyl iodide and dialkyl sulphates such as dimethyl or diethylsulphate. Suitable strong bases include, for example, sodium hydride, lithium diisopropylamide or dimsyl sodium (the sodium salt of dimethyl sulphoxide). Subsequent removal of any protecting groups present affords the desired compounds of structure (I). The intermediates of structure (II), (IV), (V) and (VI) can be prepared by standard techniques. The intermediates of structure (III) are commercially available or can be prepared by standard techniques. The compounds of structure (I) and their pharmaceutically acceptable salts exert an anti-secretory effect by inhibition of the gastrointestinal H⁺K⁺ATPase enzyme (Fellenius, E., Berglindh, T., Sachs, G., Olke, L., Elander, B., Sjostrand, S.E., and Wallmark, B., 1981, Nature, 290 , 159-61). In a further aspect therefore the present invention provides compounds of structure (I) and pharmaceutically acceptable salts thereof for use in therapy. The compounds of structure (I) and their pharmaceutically acceptable salts inhibit exogenously and endogenously stimulated gastric acid secretion and are useful in the treatment of gastrointestinal diseases in mammals, in particular humans. Such diseases include, for example, gastric and duodenal ulcers, aspiration pneumonitis and Zollinger-Ellison Syndrome. Further, the compounds of structure (I) can be used in the treatment of other disorders where an anti-secretory effect is desirable for example in patients with gastritis, NSAID induced gastritis, acute upper intestinal bleeding, in patients with a history of chronic and excessive alcohol consumption, and in patients with gastro oesophageal reflux disease (GERD). In therapeutic use, the compounds of the present invention are usually administered in a standard pharmaceutical composition. The present invention therefore provides in a further aspect pharmaceutical compositions comprising a compound of structure (I) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. The compounds of structure (I) and their pharmaceutically acceptable salts which are active when given orally can be formulated as liquids, for example syrups, suspensions or emulsions, tablets, capsules and lozenges. A liquid formulation will generally consist of a suspension or solution of the compound or pharmaceutically acceptable salt in a suitable liquid carrier(s) for example, ethanol, glycerine, non-aqueous solvent, for example polyethylene glycol, oils, or water with a suspending agent, preservative, flavouring or colouring agent. A composition in the form of a tablet can be prepared using an suitable pharmaceutical carrier(s) routinely used for preparing solid formulations. Examples of such carriers include magnesium stearate, starch, lactose, sucrose and cellulose. A composition in the form of a capsule can be prepared using routine encapsulation procedures. For example, pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), for example aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule. Typical parenteral compositions consist of a solution or suspension of the compound or pharmaceutically acceptable salt in a sterile aqueous carrier or parenterally acceptable oil, for example polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration. A typical suppository formulation comprises a compound of formula (I) or a pharmaceutically acceptable salt thereof which is active when administered in this way, with a binding and/or lubricating agent such as polymeric glycols, gelatins or cocoa butter or other low melting vegetable or synthetic waxes or fats. Preferably the composition is in unit dose form such as a tablet or capsule. Each dosage unit for oral administration contains preferably from 1 to 250 mg (and for parenteral administration contains preferably from 0.1 to 25 mg) of a compound of the formula (I) or a pharmaceutically acceptable salt thereof calculated as the free base. The present invention also provides a method of inhibiting gastric acid secretion which comprises administering to a mammal in need thereof an effective amount of a compound of the formula (I) or a pharmaceutically acceptable salt thereof; and a method of treatment of diseases of the stomach or intestine based on increased acid secretion which comprises administering to a mammal in need thereof an effective amount of a compound of the formula (I) or a pharmaceutically acceptable salt thereof. The pharmaceutically acceptable compounds of the invention will normally be administered to a subject for the treatment of gastro-intestinal diseases and other conditions caused or exacerbated by gastric acidity. The daily dosage regimen for an adult patient may be, for example, an oral dose of between 1 mg and 500 mg, preferably between 1 mg and 250 mg, or an intravenous, subcutaneous, or intramuscular dose of between 0.1 mg and 100 mg, preferably between 0.1 mg and 25 mg, of the compound of the formula (I) or a pharmaceutically acceptable salt thereof calculated as the free base, the compound being administered 1 to 4 times per day. Suitably the compounds will be administered for a period of continuous therapy, for example for a week or more. In addition, the compounds of the present invention can be co-administered with further active ingredients, such as antacids (for example magnesium carbonate or hydroxide and aluminium hydroxide), non-steroidal anti-flammatory drugs (for example indomethacin, aspirin or naproxen), steroids, or nitrite scavengers (for example ascorbic acid or aminosulphonic acid), or other drugs used for treating gastric ulcers (for example pirenzipine, prostanoids for example 16,16 dimethyl PGE₂, or histamine H₂-antagonists (for example, cimetidine). The following examples illustrate the invention. Temperatures are recorded in degrees centigrade. Example 1 Preparation of 3-butyryl-4-(4-hydroxyphenylamino)-8-methoxyquinoline 3-Butyryl-4-chloro-8-methoxyquinoline (2 g, 8 mmol), 4-aminophenol (1.24 g, 11 mmol) and 1,4-dioxan (50 ml) were heated at reflux for 2 hours, then the solid filtered off and converted to free base. Recrystallisation from ethanol and then methanol gave 3-butyryl-4-(4-hydroxyphenylamino)-8-methoxyquinoline (1.6 g), m.p. 270-272°. C₂₀H₂₀N₂O₃ Found C 71.22, H 5.87, N 8.26 Requires C 71.41, H 5.99, N 8.33 Example 2 Preparation of 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline 3-Butyryl-4-chloro-8-methoxyquinoline (3.95 g, 15 mmol), 4-amino-3-methylphenol (2.46 g, 20 mmol) and 1,4-dioxan (15 ml) were warmed briefly to reflux, then the solid filtered off and washed with ethyl acetate. Conversion to free base and recrystallisation from ethanol gave 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline (1.79 g, 34%), m.p. 252-253°. C₂₁H₂₂N₂O₃. 0.15H₂O Found C 71.41, H 6.42, N 7.90 Requires C 71.43, H 6.37, N 7.93 Example 3 Preparation of 3-butyryl-4-(4-hydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline 4-Amino-3,5-dimethylphenol (1.8 g, 1.3 mmol) and 3-butyryl-4-chloro-8-methoxyquinoline (2.6 g, 10 mmol) were heated together under reflux in 1,4-dioxan (50 ml) for 2 hours. The solvent was evaporated and the residue dissolved in dichloromethane, washed with water, sodium hydrogen carbonate solution and brine, dried and evaporated to a yellow solid which on recrystallisation from ethanol, followed by methanol, afforded 3-butyryl-4-(4-hydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline as yellow crystals, m.p. 247-8°. C₂₂H₂₄N₂O₃ Found C 72.28, H 6.62, N 7.66 Requires C 72.50, H 6.64, N 7.69 Example 4 Preparation of 3-butyryl-4-(4-hydroxy-3-fluorophenylamino)-8-methoxyquinoline 2-Fluoro-4-aminophenol (0.8 g, 6 mmol) and 3-butyryl-4-chloro-8-methoxyquinoline (1.5 g, 5.7 mmol) were heated together under reflux in 1,4-dioxan (50 ml) for 1 hour. The solvent was evaporated and the residue was dissolved in dichloromethane, washed with water, sodium hydrogen carbonate solution and brine then dried and evaporated. The residue was recrystallised from methanol-water to afford 3-butyryl-4-(3-fluoro-4-hydroxyphenylamino)-8-methoxyquinoline, m.p. 266-268°. C₂₀H₁₉FN₂O₃. 0.02CH₂Cl₂ Found C 67.34, H 5.25, N 7.71 Requires C 67.53, H 5.39, N 7.87 Example 5 Preparation of 3-butyryl-4-(3-chloro-4-hydroxyphenylamino)-8-methoxyquinoline hydrochloride 3-Butyryl-4-chloro-8-methoxyquinoline (2.64 g, 10 mmol), 2-chloro-4-aminophenol (1.58 g, 11 mmol) and 1,4-dioxan (20 ml) were warmed briefly to reflux, cooled, and the solid filtered off. Recrystallisation from pyridine gave 3-butyryl-4-(3-chloro-4-hydroxyphenylamino)-8-methoxyquinoline hydrochloride (1.40 g, 34%), m.p. 267-269° (dec). C₂₀H₁₉ClN₂O₃. HCl Found C 58.99, H 5.03, N 6.83, Cl⁻ 8.40 Requires C 58.98, H 4.95, N 6.88, Cl⁻ 8.70 Example 6 Preparation of 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoroquinoline A. Preparation of ethyl 2-butyryl-3-(2-fluorophenylamino)-acrylate 2-Fluoroaniline (25 g, 0.23 mol) and ethyl 2-butyryl-3-ethoxyacrylate (48 g, 0.23 mol) were heated at 150° for 2 hours, then diluted with petroleum ether and left to stand overnight. Filtration and washing gave ethyl 2-butyryl-3-(2-fluorophenylamino)acrylate (37.5 g), m.p. 60-62°. B. Preparation of 3-butyryl-8-fluoro-4(1H)-quinolone Ethyl 2-butyryl-3-(2-fluorophenylamino)acrylate (37 g, 0.13 mol) was added in portions to boiling diphenyl ether (450 ml), then heated at reflux for 1.5 hours. After partial cooling the mixture was diluted with petroleum ether (50 ml). Filtration and washing with petroleum ether gave 3-butyryl-8-fluoro-4(1H)-quinolone (26.5 g), m.p. 176-178°. C. Preparation of 3-butyryl-4-chloro-8-fluoroquinoline 3-Butyryl-8-fluoro-4(1H)-quinolone (2.7 g, 12 mmol) and phosphoryl chloride (40 ml) were heated at reflux for 3 hours. Excess phosphoryl chloride was evaporated in vacuo , the residue poured onto ice and neutralised with aqueous ammonia. Filtration and washing with water gave 3-butyryl-4-chloro-8-fluoroquinoline ((1.75 g), m.p. 57-60°. D. Preparation of 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoroquinoline 3-butyryl-4-chloro-8-fluoroquinoline (1.75 g, 7 mmol), 4-amino-3-methylphenol (1.3 g, 10 mmol) and 1,4-dioxan (50 ml) were heated at reflux for 6.5 hours, then the solvent evaporated and the product converted to free base. Recrystallisation from methanol gave 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoroquinoline (1.2 g), m.p. 205-207°. C₂₀H₁₉FN₂O₂ Found C 70.75, H 5.70, N 8.21 Requires C 70.99, H 5.66, N 8.28 Example 7 Preparation of 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetylquinoline A. Preparation of ethyl 2-butyryl-3-(2-acetylphenylamino)-acrylate A mixture of ethyl 2-butyryl-3-ethoxyacrylate (23.5 g, 0.11 mol) and 2′-aminoacetophenone (13.5 g, 0.1 mol) was warmed on a steam bath for 10 minutes. Crystallisation from petroleum ether gave ethyl 2-butyryl-3-(2-acetylphenylamino)acrylate as a mixture of E/Z isomers (14.9 g, 49%). B. Preparation of 3-butyryl-8-acetyl-4(1H)-quinolone Ethyl 2-butyryl-3-(2-acetylphenylamino)acrylate (14.8 g, 48.8 mmol) was added to boiling diphenyl ether (50 ml) and heated ar reflux for 3.5 hours. After cooling, the solution was poured into ether, and the solid filtered off and washed with ether to obtain 3-butyryl-8-acetyl-4(1H)-quinolone (8.8 g), contaminated with some diphenyl ether. This material was used without further purification. C. Preparation of 3-butyryl-4-chloro-8-acetylquinoline A solution of 3-butyryl-8-acetyl-4(1H)-quinolone (8.4 g) in phosphoryl chloride (30 ml) was heated at reflux for 1 hour, then poured onto ice and the product extracted into ether. Drying and evaporation gave crude 3-butyryl-4-chloro-8-acetylquinoline as a dark solid, which was used without further purification. D. Preparation of 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetylquinoline A solution of 3-butyryl-4-chloro-8-acetylquinoline (2.0 g) and 4-amino-3-methylphenol (1.23 g, 10 mmol) in 1,4-dioxan (25 ml) was warmed briefly to reflux, then the dioxan evaporated. Chromatography (silica, 4-6% methanol in dichloromethane) and recrystallisation from ethyl acetate gave 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetylquinoline (0.65 g), m.p. 183-185°. C₂₂H₂₂N₂O₃. 0.2H₂O Found C 72.19, H 6.01, N 7.59 Requires C 72.19, H 6.17, N 7.65 Example 8 Preparation of 3-butyryl-4-(4-acetoxy-2-methylphenylamino)-8-methoxyquinoline 3-Butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline (1.75 g, 5 mmol) was dissolved in a mixture of acetic anhydride (10 ml) and pyridine (10 ml), stirred for 18 hours at room temperature, then the solvent evaporated, the product dissolved in dichloromethane and washed with aqueous sodium bicarbonate. Drying, evaporation, and recrystallisation from ethyl acetate/petroleum ether gave 3-butyryl-4-(4-acetoxy-2-methylphenylamino)-8-methoxyquinoline (1.55 g, 79%), m.p. 167-169°. C₂₃H₂₄N₂O₄ Found C 70.23, H 6.00, N 7.10 Requires C 70.39, H 6.16, N 7.14 Example 9 Ethyl 8-methoxy-4-(4-hydroxy-2-methylphenylamino)-quinoline-3-carboxylate Ethyl 8-methoxy-4-chloroquinoline-3-carboxylate (2.6 g, 0.0098 mol) and 4-hydroxy-2-methylaniline (2.4 g, 0.0196 mol) in ethanol (150 ml) were heated under refulx for 30 minutes. The solvent was evaporated under reduced pressure. The residue was dissolved in chloroform and extracted with 2N hydrochloric acid (3 x 100 ml). On basification of the chloroform extracts, a solid precipitated out, this was collected by filtration and dried. Recrystallisation from dimethylformamide gave the title compound. Yield = 2.52 g, m.p. 277°-279°C. C₂₀H₂₀N₂O₄ Found C 68.12, H 5.84, N 8.09 Requires C 68.17, H 5.72, N 7.95 Example 10 Preparation of 3-butyryl-4-(4-propanoyloxy-2-methylphenylamino)-8-methoxyquinoline 3-Butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline (2.0 g, 5.7 mmol) was suspended in pyridine (25 ml), propionic anhydride (25 ml) added, and the mixture stirred for 17 hours at room temperature; the solid slowly dissolved to give a clear solution. Evaporation of the pyridine and recrystallisation from ethyl acetate/petroleum ether gave 3-butyryl-4-(4-propanoyloxy-2-methylphenylamino)-8-methoxy-quinoline (2.08 g, 90%), m.p. 163-165°. C₂₄H₂₆N₂O₄. 0.25H₂O Found C 70.11, H 6.43, N 6.74 Requires C 70.14, H 6.50, N 6.82 Example 11 Preparation of 3-butyryl-4-(4-isobutyryloxy-2-methylphenylamino)-8-methoxyquinoline 3-Butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline (2.0 g, 5.7 mmol) was suspended in pyridine (25 ml), isobutyryl chloride (5 ml) added, and the mixture stirred for 17 hours at room temperature; the solid rapidly dissolved to give a clear solution. The pyridine was evaporated, and the residue taken up in dichloromethane and washed with aqueous sodium bicarbonate and brine, dried and evaporated. Recrystallisation from isopropyl ether gave 3-butyryl-4-(4-isobutyryloxy-2-methylphenylamino)-8-methoxyquinoline (0.87 g, 36%), m.p. 123-125°. C₂₅H₂₈N₂O₄. 0.5H₂O Found C 69.83, H 6.59, N 6.41 Requires C 69.91, H 6.80, N 6.52 Example 12 Preparation of 3-isobutyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline A solution of 3-isobutyryl-4-chloro-8-methoxyquinoline (1.32 g, 5 mmol) and 4-amino-3-methylphenol (0.62 g, 5 mmol) in dioxan (50 ml) was heated at reflux for 1 hour, then cooled and the solid filtered off. This was taken up in a hot mixture of ethanol and tributylamine, cooled, and the solid filtered off. Recrystallisation from ethanol gave 3-isobutyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline (0.97 g, 55%), m.p. 243-5°. C₂₁H₂₂N₂O₃. 0.15H₂O Found C 71.49, H 6.06, N 7.95 Requires C 71.43, H 6.36, N 7.93 Example 13 Preparation of 3-butyryl-4-(4-hydroxy-3,5-dimethylphenylamino)-8-methoxyquinoline A. Preparation of 2,6-dimethyl-4-aminophenol Sulphanilic acid (43.3 g, 0.25 mol) and sodium carbonate (13.25 g, 0.125 mol) were dissolved in water (250 ml) and cooled to 15°C. Sodium nitrite (18.63 g, 0.27 mol) in water (100 ml) was added in one portion, and the mixture added immediately to concentrated hydrochloric acid (53 ml) and ice (300 g), with stirring. After 30 minutes, the resulting suspension was added to an ice-cold solution of 2,6-dimethylphenol (30.54 g, 0.25 mol) and sodium hydroxide (55 g) in water (550 ml), stirring vigorously. After 2 hours, the temperature was raised to 50°, and sodium dithionite (115 g, 0.66 mol) added portionwise. On heating to 75° the red colour discharged, and after a further 10 minutes, the solution was cooled to room temperature. The resulting white solid was filtered, washed and dried to give the title compound (27.33 g), m.p. 135-7°. B. Preparation of 3-butyryl-4-(3,5-dimethyl-4-hydroxyphenylamino)-8-methoxyquinoline 2,6-Dimethyl-4-aminophenol (0.78 g, 5.69 mmol) and 3-butyryl-4-chloro-8-methoxyquinoline (1.0 g, 3.79 mmol) in dioxan (35 ml) were refluxed under nitrogen for 2.5 hours. The solvent was evaporated, and the residue treated with saturated sodium bicarbonate solution and chloroform. The resulting solid was filtered, washed with chloroform and water, boiled in methanol and filtered again to give the title compound (0.84 g) m.p. 287-9° (dec). C₂₂H₂₄N₂O₃. 0.075CHCl₃ Found C 71.01, H 6.49, N 7.43 Requires C 71.00, H 6.50, N 7.50 Example 14 Preparation of 3-butyryl-4-(4-hydroxy-3,5-difluorophenylamino)-8-methoxyquinoline A. Preparation of 2,6-difluoro-4-aminophenol 2,6-Difluoro-4-nitrophenol (1.75 g, 10 mmol) and 10% palladium on carbon catalyst (0.3 g) in ethanol (100 ml) were shaken in a closed vessel under an initial hydrogen pressure of 3.5 bar. When hydrogen uptake was complete, the catalyst was filtered off, and the filtrate evaporated to a solid, triturated with petroleum ether, filtered, washed and dried to give the title compound (1.31 g), m.p. indeterminate. B. Preparation of 3-butyryl-4-(3,5-difluoro-4-hydroxyphenylamino)-8-methoxyquinoline 2,6-Difluoro-4-aminophenol (1.49 g, 5.65 mmol) and 3-butyryl-4-chloro-8-methoxyquinoline (1.23 g, 8.48 mmol) in dioxan (50 ml) were refluxed under nitrogen for 2.5 hours. The solvent was evaporated and the product was converted to the free base, purified by flash chromatography (silica, methanol-ammonia/chloroform), triturated with methanol, filtered, washed and dried to give the title compound (0.58 g), m.p. 274-5° (dec). C₂₀H₂₈F₂N₂O₃. 0.15CHCl₃ Found C 61.87, H 4.67, N 7.18 Requires C 62.01, H 4.69, N 7.18 Example 15 Preparation of 3-butyryl-4-(3,4-dihydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline A. Preparation of cyclohexanone 4-amino-3,5-dimethyl-1,2-phenylene acetal. Cyclohexanone 4-nitro-3,5-dimethyl-1,2-phenylene acetal (10.0 g) and 10% palladium on charcoal (1.0 g) in ethanol (200 ml) was shaken in a hydrogen atmosphere (50 p.s.i.) at 45°C for 3 hours. The mixture was filtered through celite and evaporated to leave cyclohexanone 4-amino-3,5-dimethyl-1,2-phenylene acetal (8.0 g, 90%) as a brown oil. B. Preparation of the cyclohexanone acetal of 3-butyryl-4-(3,4-dihydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline. Cyclohexanone 4-amino-3,5-dimethyl-1,2-phenylene acetal (3.1 g, 13 mmol) and 3-butyryl-4-chloro-8-methoxyquinoline (2.75 g, 12 mmol) were heated together under reflux in 1,4-dioxan (50 ml) for 1.5 hours. The solvent was evaporated and the residue was dissolved in chloroform, washed with 2M HCl, sodium hydrogen carbonate solution and brine. Evaporation and crystallisation from ether gave cyclohexanone 4-(3-butyryl-8-methoxy-4-quinolinyl)amino-3,5-dimethyl-1,2-phenylene acetal (2.2 g) as light brown crystals. Chromatography of the mother liquors gave an additional 1.0 g of the title compound (total 3.2 g, 57%), m.p. 151-3°. C. Preparation of 3-butyryl-4-(3,4-dihydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline. The product from B (1.0 g) in 5M hydrochloric acid (50 ml) was heated under reflux for 10 minutes, ensuring all the solid had dissolved. The mixture was cooled and carefully taken to pH7 by the addition of sodium hydrogen carbonate solution. The yellow solid which appeared was filtered off, washed with water, dichloromethane and ether and dried in vacuo to give 3-butyryl-4-(3,4-dihydroxy-2,6-dimethylphenylamino)-8-methoxyquinoline (0.75 g, 90%), m.p. 288-90°C. C₂₂H₂₄N₂O₄ Found C 69.32, H 6.40, N 7.21 Requires C 69.46, H 6.36, N 7.36 Example A A tablet for oral administration is prepared by combining mg/Tablet Compound of structure (I) 100 lactose 153 Starch 33 crospovidone 12 microcrystalline cellulose 30 magnesium stearate 2 330 mg into a 9 mm tablet. Example B An injection for parenteral administration is prepared from the following %w:w Compound of structure (I) 0,50% (w:v) 1M citric acid 30% (v:v) sodium hydroxide (qs) to pH 3.2 water for injection EP to 100 ml The compound of structure (I) is dissolved in the citric acid and the pH slowly adjusted to pH 3.2 with the sodium hydroxide solution. The solution is then made up to 100 ml with water, sterilised by filtration and sealed into appropriately sized ampoules and vials. Biological Data. H ⁺K⁺ ATPase Activity . The effects of a single high concentration (100 µM) of a compound of structure (I) on K⁺-stimulated ATPase activity in lyophilised gastric vesicles was determined. Preferred compounds of structure (I) were also tested over a range of concentrations to determine IC₅₀ values. (i) Preparation of lyophilised gastric vesicles (H/K-ATPase) Lyophilised gastric vesicles were prepared from pig fundic mucosa after the method of Keeling et. al. (Biochem. Pharmacol., 34 , 2967, 1985). (ii) K ⁺ -stimulated ATPase activity . K⁺-stimulated ATPase activity was determined at 37°C in the presence of the following : 10 mM Pipes/Tris buffer pH 7.0, 2 mM MgSO₄, 1 mM KCl, 2 mM Na₂ATP and 3-6 g protein/ml lyophilised gastric vesicles. After incubation for 30 minutes, the inorganic phosphate hydrolyzed from ATP was determined by the method of Yoda and Hokin (Biochem. Biophys. Res. Commun. 40 , 880, 1970). Compounds of structure (I) were dissolved in dimethylsulphoxide which up to the highest concentration used had no effect on K⁺-stimulated ATPase activity. The effect of the highest concentration of each compound of structure (I) on the recovery of a standard amount of inorganic phosphate was also determined. The results obtained were as follows: Compound IC₅₀(µM) 1 0.67 2 0.21 3 0.50 6 0.71 7 0.55 9 0.08 12 0.16 15 2.80 16 0.07 17 1.30

Claims: Claims for the following Contracting States : AT, BE, CH, DE, FR, GB, IT, LI, LU, NL, SE A compound of structure (I) : in which R¹ is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, C₁₋₆alkoxyC₁₋₆-alkyl, C₃₋₆cycloalkyl, C₃₋₆cycloalkylC₁₋₆alkyl, phenylC₁₋₆alkyl, the phenyl group being optionally substituted by 1-3 substituents selected from C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; R² is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; m is 1 to 3; R³ is hydrogen, C₁₋₆alkyl, phenyl, C₁₋₆alkoxy, C₁₋₆alkylthio, C₁₋₆alkanoyl, amino, C₁₋₆alkylamino, di-C₁₋₆alkylamino, halogen, trifluoromethyl or cyano; n is 1 or 2; and R⁴O- is hydroxy or a bioprecursor of a hydroxy group chosen from C₁₋₆alkanoyloxy, aryl C₁₋₆alkanoyloxy, arylsulphonyloxy or alkylsulphonyloxy; or a salt thereof. A compound according to claim 1 in which m is 1. A compound according to claim 2 in which R² is a C₁₋₆alkyl group in the 2-position of the phenyl ring. A compound according to claim 3 in which n is 1 and R³ is a C₁₋₆alkoxy group. A compound according to claim 4 in which the group R³ is in the 8-position. A compound according to claim 1 which is 3-butyryl-4-(4-hydroxyphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2,6-dimethylphenylamino)-8-methoxy-quinoline 3-butyryl-4-(4-hydroxy-3-fluorophenylamino)-8-methoxyquinoline 3-butyryl-4-(3-chloro-4-hydroxyphenylamino)-8-methoxyquinoline hydrochloride 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoroquinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetylquinoline 3-butyryl-4-(4-acetoxy-2-methylphenylamino)-8-methoxyquinoline A pharmaceutical composition comprising a compound according to any one of claims 1 to 6 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. A compound according to any one of claims 1 to 6 for use in therapy. A compound according to any one of claims 1 to 6 for use in the inhibition of gastric acid secretion. A process for the preparation of a compound according to claim 1 which comprises (a) reaction of a compound of structure (II) and a compound of structure (III) : in which R¹, R², R³, n and m are as described for structure (I), R⁵ is hydrogen or a protecting group and X is a group displaceable by an amine; (b) reduction of a compound of structure (IV) : in which R¹, R², R³, n and m are as described for structure (I), R⁵ is a hydrogen or a protecting group and R⁶ is hydrogen or a nitrogen protecting group; (c) for compounds of structure (I) in which R¹ is other than C₁₋₆alkoxy, oxidation of a compound of structure (V) : in which R², R³, n and m are as described for structure (I), R 1' is a group R¹ other than C₁₋₆alkoxy and R⁵ and R⁶ are as described for structure (IV); and thereafter if desired, removing any protecting groups; converting a group R¹ into another group R¹; forming a salt. Claims for the following Contracting States : ES, GR A process for the preparation of a compound of structure (I) : in which R¹ is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, C₁₋₆alkoxyC₁₋₆-alkyl, C₃₋₆cycloalkyl, C₃₋₆cycloalkylC₁₋₆alkyl, phenylC₁₋₆alkyl, the phenyl group being optionally substituted by 1-3 substituents selected from C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; R² is hydrogen, C₁₋₆alkyl, C₁₋₆alkoxy, amino, C₁₋₆alkylthio, halogen, cyano, hydroxy, C₁₋₆alkanoyl or trifluoromethyl; m is 1 to 3; R³ is hydrogen, C₁₋₆alkyl, phenyl, C₁₋₆alkoxy, C₁₋₆alkylthio, C₁₋₆alkanoyl, amino, C₁₋₆alkylamino, di-C₁₋₆alkylamino, halogen, trifluoromethyl or cyano; n is 1 or 2; and R⁴O- is hydroxy or a bioprecursor of a hydroxy group chosen from C₁₋₆alkanoyloxy, aryl C₁₋₆alkanoyloxy, arylsulphonyloxy or alkylsulphonyloxy; or a salt thereof, which comprises (a) reaction of a compound of structure (II) and a compound of structure (III) : in which R¹, R², R³, n and m are as described for structure (I), R⁵ is hydrogen or a protecting group and X is a group displaceable by an amine; (b) reduction of a compound of structure (IV) : in which R¹, R², R³, n and m are as described for structure (I), R⁵ is a hydrogen or a protecting group and R⁶ is hydrogen or a nitrogen protecting group; (c) for compounds of structure (I) in which R¹ is other than C₁₋₆alkoxy, oxidation of a compound of structure (V) : in which R², R³, n and m are as described for structure (I) R¹' is a group R¹ other than C₁₋₆alkoxy and R⁵ and R⁶ are as described for structure (IV); and thereafter if desired, removing any protecting groups; converting a group R¹ into another group R¹; forming a salt. A process according to claim 1(a) in which the reaction is carried out in the presence of a solvent. A process according to claim 2 in which the solvent is dioxan. A process according to claim 3 in which in the compound of structure (I) m is 1. A process according to claim 4 in which in the compound of structure (I) R² is a C₁₋₆alkyl group in the 2-position of the phenyl ring. A process according to claim 5 in which in the compound of structure (I) n is 1 and R³ is a C₁₋₆alkoxy group. A process according to claim 6 in which in the compound of structure (I) the group R³ is in the 8-position. A process according to claim 7 in which the compound of structure (I) is selected from 3-butyryl-4-(4-hydroxyphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2,6-dimethylphenylamino)-8-methoxy-quinoline 3-butyryl-4-(4-hydroxy-3-fluorophenylamino)-8-methoxyquinoline 3-butyryl-4-(3-chloro-4-hydroxyphenylamino)-8-methoxyquinoline hydrochloride 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoroquinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetylquinoline or 3-butyryl-4-(4-acetoxy-2-methylphenylamino)-8-methoxyquinoline or a salt thereof. A process for preparing a pharmaceutical composition which comprises bringing into association a compound of structure (I) as described in claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. A process according to claim 9 in which the compound of structure (I) is selected from 3-butyryl-4-(4-hydroxyphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-methoxyquinoline 3-butyryl-4-(4-hydroxy-2,6-dimethylphenylamino)-8-methoxy-quinoline 3-butyryl-4-(4-hydroxy-3-fluorophenylamino)-8-methoxy-quinoline 3-butyryl-4-(3-chloro-4-hydroxyphenylamino)-8-methoxy-quinoline hydrochloride 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-fluoro-quinoline 3-butyryl-4-(4-hydroxy-2-methylphenylamino)-8-acetyl-quinoline or 3-butyryl-4-(4-acetoxy-2-methylphenylamino)-8-methoxy-quinoline

Inventors: BROWN, THOMAS HENRY, IFE, ROBERT JOHN, LEACH, COLIN ANDREW
Applicants: SMITHKLINE BEECHAM INTERCREDIT B.V.
Application year: 1989
Main classification: C07D215
IPC codes: A61P1, C07D215, A61K31, A61P43