AZABICYCLONONYL-INDAZOLE-CARBOXAMIDE HAVING 5-HT ANTAGONIST ACTIVITY

Abstract: Compounds of formula (I) and pharmaceutically accept­ able salts thereof: wherein X is CO and Y is NH or O, or X is NH and Y is CO; Z is CH₂, O, S or NR₃ wherein R₃ is hydrogen, C₁₋₆ alkyl, C₃₋₇ alkenyl-methyl, phenyl or phenyl C₁₋₄ alkyl either of which phenyl moieties may be substituted by one or two of halogen, CF₃, C₁₋₆ alkoxy or C₁₋₆ alkyl; and R a is not present; or Z is CH or N and R a is as defined for R₃ above; R b is present when X-Y-R₂ is attached at the phenyl ring and is selected from hydrogen, halogen, CF₃, hydroxy, C₁₋₆ alkoxy or C₁₋₆ alkyl; R₁ is hydrogen, halogen, CF₃, C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkylthio, C₁₋₇ acyl, C₁₋₇ acylamino, C₁₋₆ alkylsulphonylamino, N-(C₁₋₆ alkylsulphonyl)-N-C₁₋₄ alkylamino, C₁₋₆ alkylsulphinyl, hydroxy, nitro or amino, aminocarbonyl, aminosulphonyl, aminosulphonylamino or N-(aminosulphonyl)-C₁₋₄ alkylami- no optionally N-substituted by one or two groups selected from C₁₋₆ alkyl, C₃₋₈ cycloalkyl, C₃₋₈ cycloalkyl C₁₋₄ alkyl, phenyl or phenyl C₁₋₄ alkyl groups or optionally N-­ disubstituted by C₄₋₅ polymethylene; R₂ is a group of formula (a), (b) or (c) wherein n is 2 or 3; p and q are independently 1 to 3; and R₄ or R₅ is C₁₋₇ alkyl, C₃₋₈ cycloalkyl, C₃₋₈ cycloalkyl-c₁₋₂ alkyl, or a group (CH₂) t R₆ where t is 1 or 2 and R₆ thienyl,

Description: This invention relates to a novel compound having useful pharmacological properties, to pharmaceutical compositions containing it, to a process for its preparation, and to its use as a pharmaceutical. UK Patent Applications, GB 2100259A, 2125398A (corresponding to WO 84/00166) and GB 2145416A (corresponding to WO 85/01048), describe aryl esters and amides having an azabicyclic side chain and possessing 5-HT (5-Hydroxytryptamine) antagonist activity. A novel, structurally distinct compound has now been discovered. This compound has 5-HT antagonist activity. Accordingly, the present invention provides a compound of formula (I), or a pharmaceutically acceptable salt thereof: The pharmaceutically acceptable salts of the compound of the formula (I) include acid addition salts with conventional acids such as hydrochloric, hydrobromic, boric, phosphoric, sulphuric acids and pharmaceutically acceptable organic acids such as acetic, tartaric, maleic, citric, succinic, benzoic, ascorbic, methanesulphonic, α-keto glutaric, α-glycerophosphoric, and glucose-1-phosphoric acids. The pharmaceutically acceptable salts of the compound of the formula (I) are usually acid addition salts with acids such as hydrochloric, hydrobromic, phosphoric, sulphuric, citric, tartaric, lactic and acetic acid. Preferably the acid addition salt is the hydrochloride salt. Examples of pharmaceutically acceptable salts include quaternary derivatives of the compound of formula (I) such as the compounds quaternised by compounds R₁₀-T wherein R₁₀ is C₁₋₆ alkyl, phenyl-C₁₋₆ alkyl or C₅₋₇ cycloalkyl, and T is a radical corresponding to an anion of an acid. Suitable examples of R₁₀ include methyl, ethyl and n - and iso -propyl; and benzyl and phenethyl. Suitable examples of T include halide such as chloride, bromide and iodide. Examples of pharmaceutically acceptable salts of the compound of formula (I) also form internal salts such as pharmaceutically acceptable N-oxides. The compound of the formula (I) and its pharmaceutically acceptable salts, (including quaternary derivatives and N-oxides) may also form pharmaceutically acceptable solvates, such as hydrates, which are included whenever the compound and salts are herein referred to. The invention also provides a process for the preparation of a compound of formula (I), or a pharmaceutically acceptable salt thereof, which process comprises reacting a compound of formula (II): with a compound of formula (III): wherein Q₁ is a group displaceable by a nucleophile, and thereafter optionally forming a pharmaceutically acceptable salt of the resultant compound of formula (I). Examples of leaving groups Q₁, displaceable by a nucleophile include halogen such as chloro and bromo, hydroxy, carboxylic acyloxy such as C₁₋₄ alkanoyloxy or C₁₋₄ alkoxycarbonyloxy and activated hydrocarbyloxy such as pentachlorophenoxy. If a group Q₁ is a halide, then the reaction is preferably carried out at non-extreme temperatures in an inert non-hydroxylic solvent, such as benzene, dichloromethane, toluene, diethyl ether, THF (tetrahydrofuran) or DMF (dimethylformamide). It is also preferably carried out in the presence of an acid acceptor, such as an organic base, in particular a tertiary amine, such as triethylamine, trimethylamine, pyridine or picoline, some of which can also function as the solvent. Alternatively, the acid acceptor can be inorganic, such as calcium carbonate, sodium carbonate or potassium carbonate. Temperatures of 0 o -100 o C, in particular 10-80 o C are suitable. If a group Q₁ is hydroxy, then the reaction is generally carried out in an inert non-hydroxylic solvent, such as dichloromethane, THF or DMF optionally in the presence of a dehydrating catalyst, such as a carbodiimide, for example dicyclohexylcarbodiimide. The reaction may be carried out at any non-extreme temperature, such as -10 to 100 o C, for example, 0 to 80 o C. Generally, higher reaction temperatures are employed with less active compounds whereas lower temperatures are employed with the more active compounds. If a group Q₁ is carboxylic acyloxy, then the reaction is preferably carried in substantially the same manner as the reaction when Q₁ is halide. Suitable examples of acyloxy leaving groups include C₁-₄ alkanoyloxy and C₁₋₄ alkoxycarbonyloxy, in which case the reaction is preferably carried out in an inert solvent, such as methylene chloride, at a non-extreme temperature for example ambient temperatures in the presence of an acid acceptor, such as triethylamine. C₁₋₄ alkoxy- carbonyloxy leaving groups may be generated in situ by treatment of the corresponding compound wherein Q₁ is hydroxy with a C₁-₄ alkyl chloroformate. If a group Q₁ is activated hydrocarbyloxy then the reaction is preferably carried out in an inert polar solvent, such as dimethylformamide. It is also preferred that the activated hydrocarbyloxy group is a pentachlorophenyl ester and that the reaction is carried out at ambient temperature. Pharmaceutically acceptable salts of the compound of this invention may be formed conventionally. The salts may be formed for example by reaction of then base compound of formula (I) with a pharmaceutically acceptable organic or inorganic acid. The compounds of formula (II) and (III) are known compounds. The compound of the present invention is a 5-HT antagonist and it is thus believed may generally be used in the treatment or prophylaxis of migraine, cluster headaches and trigeminal neuralgia; and also as an anti-emetic, in particular that of preventing vomiting and nausea associated with cancer therapy. Examples of such cancer therapy include that using cytotoxic agents, such as cisplatin, doxorubicin and cyclophosphamide, particularly cisplatin; and also radiation treatment. Compounds which are 5-HT antagonists may also be of potential use in the treatment of CNS disorders such as anxiety and psychosis; arrhythmia, obesity and irritable bowel syndrome. The invention also provides a pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. Such compositions are prepared by admixture and are suitably adapted for oral or parenteral administration, and as such may be in the form of tablets, capsules, oral liquid preparations, powders, granules, lozenges, reconstitutable powders, injectable and infusable solutions or suspensions or suppositories. Orally administrable compositions are preferred, since they are more convenient for general use. Tablets and capsules for oral administration are usually presented in a unit dose, and contain conventional excipients such as binding agents, fillers, diluents, tabletting agents, lubricants, disintegrants, colourants, flavourings, and wetting agents. The tablets may be coated according to well known methods in the art, for example with an enteric coating. Suitable fillers for use include cellulose, mannitol, lactose and other similar agents. Suitable disintegrants include starch, polyvinylpolypyrrolidone and starch derivatives such as sodium starch glycollate. Suitable lubricants include, for example, magnesium stearate. Suitable pharmaceutically acceptable wetting agents include sodium lauryl sulphate. Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups, or elixirs, or may be presented as a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, for example sorbitol, syrup, methyl cellulose, gelatin, hydroxyethylcellulose, carboxymethylcellulose, aluminium stearate gel or hydrogenated edible fats, emulsifying agents, for example lecithin, sorbitan monooleate, or acacia; non-aqueous vehicles (which may include edible oils), for example, almond oil, fractionated coconut oil, oily esters such as esters of glycerine, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid, and if desired conventional flavouring or colouring agents. Oral liquid preparations are usually in the form of aqueous or oily suspensions, solutions, emulsions, syrups, or elixirs or are presented as a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils), preservatives, and flavouring or colouring agents. The oral compositions may be prepared by conventional methods of blending, filling or tabletting. Repeated blending operations may be used to distribute the active agent throughout those compositions employing large quantities of fillers. Such operations are, of course, conventional in the art. For parenteral administration, fluid unit dose forms are prepared containing a compound of the present invention and a sterile vehicle. The compound, depending on the vehicle and the concentration, can be either suspended or dissolved. Parenteral solutions are normally prepared by dissolving the compound in a vehicle and filter sterilising before filling into a suitable vial or ampoule and sealing. Advantageously, adjuvants such as a local anaesthetic, preservatives and buffering agents are also dissolved in the vehicle. To enhance the stability, the composition can be frozen after filling into the vial and the water removed under vacuum. Parenteral suspensions are prepared in substantially the same manner except that the compound is suspended in the vehicle instead of being dissolved and sterilised by exposure of ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the compound of the invention. The invention further provides a method of treatment or prophylaxis of migraine, cluster headache, trigeminal neuralgia and/or emesis in mammals, such as humans, which comprises the administration to the mammal of an effective amount of a compound of the formula (I) or a pharmaceutically acceptable salt thereof. An amount effective to treat the disorders hereinbefore described depends on the nature and severity of the disorder being treated and the weight of the mammal. However, a unit dose for a 70kg adult will normally contain 0.5 to 1000mg for example 1 to 500mg, of the compound of the invention. Unit doses may be administered once or more than once a day, for example, 2,3 or 4 times a day, more usually 1 to 3 times a day, that is in the range of approximately 0.001 to 50 mg/kg/day, more usually 0.002 to 25 mg/kg/day. No adverse toxicological effects are indicated at any of the aforementioned dosage ranges. The invention also provides a compound of formula (I) or a pharmaceutically acceptable salt thereof for use as an active therapeutic substance, in particular for use in the treatment of migraine, cluster headache, trigeminal neuralgia and/or emesis. The following Example illustrates the preparation of the compound of formula (I). N.B. Nomenclature is based on Chemical Abstracts Index Guide 1977 published by the American Chemical Society. Example N-( endo -9-Methyl-9-azabicyclo[3.3.1]non-3-yl)1-methylindazole-3-carboxamide monohydrochloride A stirred solution of 1-methylindazole-3-carboxylic acid chloride(0.77g) in dichloromethane (50ml) was treated with a solution of endo -9-methyl-9-azabicyclo[3.3.1]nonan-3-amine (0.7g) and triethylamine (0.7ml) in dichloromethane (30ml). After 2h, the reaction mixture was washed with saturated aqueous NaHCO₃ (100ml) and dried (K₂CO₃). The oil remaining after evaporation of the solvent was purified by column chromatography (TLC-alumina, CHCl₃) and treated with hydrogen chloride to give the title compound m.p. 290-2 o C. ¹H NMR (270 MHz, CDCl₃) δ: 8.30 (d, 1H) 7.50-7.20 (m, 4H) 4.80-4.50 (m, 1H) 4.12 and 4.10 (2-s, 3H) 3.75-3.55 (m, 2H) 2.99 and 2.91 (2-s, 3H) 2.82-2.40 (m, 4H) 2.20-2.00 (m, 2H) 1.90-1.60 (m, 4H) Pharmacology Antagonism of the von Bezold-Jarisch reflex The compound of the Example was evaluated for antagonism of the von Bezold-Jarisch reflex evoked by 5-HT in the anaesthetised rat according to the following method: Male rats 250-350g, were anaesthetised with urethane (1.25g/kg intraperitoneally) and blood pressure and heart rate recorded as described by Fozard J.R. et al., J. Cardiovasc. Pharmacol. 2, 229-245 (1980). A submaximal dose of 5-HT (usually 6µg/kg) was given repeatedly by the intravenous route and changes in heart rate quantified. The compound was given intravenously and the concentration required to reduce the 5-HT evoked response to 50% of the control response (ED₅₀) was then determined. The compound gave an ED₅₀ value of 0.7 µg/kg.

Claims: A compound of formula (I), or a pharmaceutically acceptable salt thereof: N-(endo-9-Methyl-9-azabicyclo[3.3.1]non-3-yl)-1-methylindazole-3-carboxamide monohydrochloride. A process for the preparation of a compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt there of, which process comprises reacting a compound of formula (II): with a compound of formula (III): wherein Q₁ is a group displaceable by a nucleophile, and thereafter optionally forming a pharmaceutically acceptable salt of the resultant compound of formula (I). A pharmaceutical composition comprising a compound according to claim 1 or 2, and a pharmaceutically acceptable carrier. A composition according to claim 4, adapted for parenteral administration. A composition according to claim 4, adapted for oral administration. A compound according to claim 1 or 2 for use as an active therapeutic substance. A compound according to claim 1 or 2, for use in the treatment of emesis. A compound according to claim 1 or 2, for use in the treatment of cytotoxic agent induced vomiting and nausea. A compound according to claim 1 or 2 for use in the treatment of migraine, cluster headache or trigeminal neuralgia. A compound according to claim 1 or 2 for use in the treatment of CNS disorders. Use of a compound according to claim 1 or 2 in the manufacture of a medicament for use in the treatment of emesis. Use of a compound according to claim 1 or 2 in the manufacture of a medicament for use in the treatment of cytotoxic agent induced vomiting and nausea. Use of a compound according to claim 1 or 2 in the manufacture of a medicament for use in the treatment of migraine, cluster headache or trigeminal neuralgia. Use of a compound according to claim 1 or 2 in the manufacture of a medicament for use in the treatment of CNS disorders.

Inventors: KING, FRANCIS DAVID, KING, FRANCIS DAVID, C/O SMITHKLINE BEECHAM
Applicants: BEECHAM GROUP PLC
Application year: 1986
Main classification: C07D451
IPC codes: A61K31, C07D451, C07D487, C07D453, A61P25, A61P1, A61P43, A61P9, C07D403, C07D471, A61P3