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WO2000047582A1 - Derives de la triazolo-pyridazine, liants des recepteurs du gaba - Google Patents

Derives de la triazolo-pyridazine, liants des recepteurs du gaba Download PDF

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Publication number
WO2000047582A1
WO2000047582A1 PCT/GB2000/000308 GB0000308W WO0047582A1 WO 2000047582 A1 WO2000047582 A1 WO 2000047582A1 GB 0000308 W GB0000308 W GB 0000308W WO 0047582 A1 WO0047582 A1 WO 0047582A1
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Prior art keywords
methyl
triazolo
triazol
compound
formula
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William Robert Carling
Andrew Mitchinson
Michael Geoffrey Neil Russell
Leslie Joseph Street
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Organon Pharma UK Ltd
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Merck Sharp and Dohme Ltd
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Priority to AU23065/00A priority Critical patent/AU2306500A/en
Priority to EP00901765A priority patent/EP1150983A1/fr
Priority to JP2000598502A priority patent/JP2002536449A/ja
Priority to CA002362400A priority patent/CA2362400A1/fr
Publication of WO2000047582A1 publication Critical patent/WO2000047582A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
    • C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
    • C07D487/04—Ortho-condensed systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A61P25/08—Antiepileptics; Anticonvulsants
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A61P25/22—Anxiolytics

Definitions

  • the present invention relates to a class of substituted triazolo- pyridazine derivatives and to their use in therapy. More particularly, this invention is concerned with substituted l,2,4-triazolo[4,3-6]pyridazine derivatives which are ligands for GABAA receptors and are therefore useful in the therapy of deleterious mental states.
  • GABA gamma- aminobutyric acid
  • GABA A receptors which are members of the ligand-gated ion channel superfamily
  • GABAB receptors which may be members of the G-protein linked receptor superfamily. Since the first cDNAs encoding individual GABAA receptor subunits were cloned the number of known members of the mammalian family has grown to include at least six ⁇ subunits, four ⁇ subunits, three ⁇ subunits, one ⁇ subunit, one ⁇ subunit and two p subunits.
  • Receptor subtype assemblies which do exist include, amongst many others, ⁇ l ⁇ 2 ⁇ 2, ⁇ 2 ⁇ 2/3 ⁇ 2, ⁇ 3 ⁇ 2/3, ⁇ 2 ⁇ l, ⁇ 5 ⁇ 3 ⁇ 2/3, ⁇ 6 ⁇ 2, ⁇ 6 ⁇ and ⁇ 4 ⁇ .
  • Subtype assemblies containing an ⁇ l subunit are present in most areas of the brain and are thought to account for over 40% of GABAA receptors in the rat.
  • Subtype assemblies containing ⁇ 2 and ⁇ 3 subunits respectively are thought to account for about 25% and 17% of GABAA receptors in the rat.
  • Subtype assemblies containing an a ⁇ subunit are expressed predominantly in the hippocampus and cortex and are thought to represent about 4% of GABAA receptors in the rat.
  • a characteristic property of all known GABAA receptors is the presence of a number of modulatory sites, one of which is the benzodiazepine (BZ) binding site.
  • the BZ binding site is the most explored of the GABAA receptor modulatory sites, and is the site through which anxiolytic drugs such as diazepam and temazepam exert their effect.
  • the benzodiazepine binding site was historically subdivided into two subtypes, BZ1 and BZ2. on the basis of radioligand binding studies.
  • the BZl subtype has been shown to be pharmacologically equivalent to a GABAA receptor comprising the ⁇ l subunit in combination with a ⁇ subunit and ⁇ 2. This is the most abundant GABAA receptor subtype, and is believed to represent almost half of all GABAA receptors in the brain. Two other major populations are the ⁇ 2 ⁇ 2 and ⁇ 3 ⁇ 2/3 subtypes.
  • GABAA receptor agonists Compounds which are modulators of the benzodiazepine binding site of the GABAA receptor by acting as BZ agonists are referred to hereinafter as "GABAA receptor agonists".
  • GABAA receptor agonists Compounds which are modulators of the benzodiazepine binding site of the GABAA receptor by acting as BZ agonists.
  • the ⁇ l-selective GABAA receptor agonists alpidem and zolpidem are clinically prescribed as hypnotic agents, suggesting that at least some of the sedation associated with known anxiolytic drugs which act at the BZ1 binding site is mediated through GABAA receptors containing the ⁇ l subunit.
  • GABAA receptor agonists which interact more favourably with the ⁇ 2 and/or ⁇ 3 subunit than with ⁇ l will be effective in the treatment of anxiety with a reduced propensity to cause sedation.
  • agents which are antagonists or inverse agonists at ⁇ l might be employed to reverse sedation or hypnosis caused by ⁇ l agonists.
  • the compounds of the present invention being selective ligands for GABAA receptors, are therefore of use in the treatment and/or prevention of a variety of disorders of the central nervous system.
  • disorders include anxiety disorders, such as panic disorder with or without agoraphobia, agoraphobia without history of panic disorder, animal and other phobias including social phobias, obsessive-compulsive disorder, stress disorders including post-traumatic and acute stress disorder, and generalized or substance-induced anxiety disorder; neuroses; convulsions; migraine; depressive or bipolar disorders, for example single-episode or recurrent major depressive disorder, dysthymic disorder, bipolar I and bipolar II manic disorders, and cyclothymic disorder; psychotic disorders including schizophrenia; neurodegeneration arising from cerebral ischemia; attention deficit hy er activity disorder; and disorders of circadian rhythm, e.g.
  • GABAA receptors include pain and nociception; emesis, including acute, delayed and anticipatory emesis, in particular emesis induced by chemotherapy or radiation, as well as post-operative nausea and vomiting; eating disorders including anorexia nervosa and bulimia nervosa; premenstrual syndrome; muscle spasm or spasticity, e.g. in paraplegic patients; and hearing loss.
  • Selective ligands for GABAA receptors may also be effective as pre-medication prior to anaesthesia or minor procedures such as endoscopy, including gastric endoscopy.
  • WO 98/04559 describes a class of substituted and 7,8-ring fused l,2,4-triazolo[4,3-6]pyridazine derivatives which are stated to be selective ligands for GABAA receptors beneficial in the treatment and/or prevention of neurological disorders including anxiety and convulsions.
  • the present invention provides a class of triazolo-pyridazine derivatives which possess desirable binding properties at various GABA A receptor subtypes.
  • the compounds in accordance with the present invention have good affinity as ligands for the ⁇ 2 and/or ⁇ 3 subunit of the human GABAA receptor.
  • the compounds of this invention may interact more favourably with the ⁇ 2 and/or ⁇ 3 subunit than with the ⁇ l subunit.
  • the compounds of the invention will exhibit functional selectivity in terms of a selective efficacy for the ⁇ 2 and/or ⁇ 3 subunit relative to the ⁇ l subunit.
  • the compounds of the present invention are GABAA receptor subtype ligands having a binding affinity (Ki) for the ⁇ 2 and/or ⁇ 3 subunit, as measured in the assay described hereinbelow, of 100 nM or less, typically of 50 nM or less, and ideally of 10 nM or less.
  • the compounds in accordance with this invention may possess at least a 2-fold, suitably at least a 5-fold, and advantageously at least a 10-fold, selective affinity for the ⁇ 2 and/or ⁇ 3 subunit relative to the ⁇ l subunit.
  • compounds which are not selective in terms of their binding affinity for the ⁇ 2 and/or ⁇ 3 subunit relative to the ⁇ l subunit are also encompassed within the scope of the present invention; such compounds will desirably exhibit functional selectivity in terms of a selective efficacy for the ⁇ 2 and/or ⁇ 3 subunit relative to the ⁇ l subunit.
  • the compounds according to the present invention may possess interesting pharmacokinetic properties, notably in terms of improved oral bioavailability.
  • the present invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof:
  • Z represents tert-butyl, cyclobutyl, phenyl or pyrrolidin-1-yl;
  • R 1 represents hydrogen, methyl, methoxy or fluoro;
  • R 2 represents hydrogen or fluoro;
  • R 3 represents hydrogen, methyl or ethyl;
  • R 4 represents trifluoromethyl, chloromethyl, or a group of formula
  • R a represents hydrogen, methyl or tert-butyldimethylsilanyl; and R b and R c both represent methyl; or R b and R c together represent the residue of an azetidine, 3,3-difluoroazetidine, pyrrolidine, morpholine or N-methylpiperazine moiety.
  • the salts of the compounds of formula I will be pharmaceutically acceptable salts.
  • Other salts may, however, be useful in the preparation of the compounds of formula I or of their pharmaceutically acceptable salts.
  • Suitable pharmaceutically acceptable salts of the compounds of formula I include acid addition salts which may, for example, be formed by mixing a solution of the compound of formula I with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, sulphuric acid, methanesulphonic acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, oxalic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid.
  • a pharmaceutically acceptable acid such as hydrochloric acid, sulphuric acid, methanesulphonic acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, oxalic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid.
  • the moiety Z suitably represents tert-butyl, phenyl or pyrrolidin-1-yl.
  • R 1 represents hydrogen or fluoro.
  • R 2 represents hydrogen
  • R 3 represents methyl or ethyl.
  • R a represents hydrogen or methyl.
  • Also provided by the present invention is a method for the treatment and/or prevention of anxiety which comprises administering to a patient in need of such treatment an effective amount of a compound of formula I as defined above or a pharmaceutically acceptable salt thereof.
  • a method for the treatment and/or prevention of convulsions e.g. in a patient suffering from epilepsy or a related disorder which comprises administering to a patient in need of such treatment an effective amount of a compound of formula I as defined above or a pharmaceutically acceptable salt thereof.
  • the binding affinity (Ki) of the compounds according to the present invention for the ⁇ 3 subunit of the human GABAA receptor is conveniently as measured in the assay described hereinbelow.
  • the ⁇ 3 subunit binding affinity (Ki) of the compounds of the invention is ideally 10 nM or less, preferably 2 nM or less, and more preferably 1 nM or less.
  • the compounds according to the present invention will ideally elicit at least a 40%, preferably at least a 50%, and more preferably at least a 60%, potentiation of the GABA EC20 response in stably transfected recombinant cell lines expressing the ⁇ 3 subunit of the human GABA A receptor. Moreover, the compounds of the invention will ideally elicit at most a 30%, preferably at most a 20%, and more preferably at most a 10%, potentiation of the GABA EC20 response in stably transfected recombinant cell lines expressing the ⁇ l subunit of the human GABAA receptor.
  • the potentiation of the GABA EC20 response in stably transfected cell lines expressing the ⁇ 3 and ⁇ l subunits of the human GABAA receptor can conveniently be measured by procedures analogous to the protocol described in Wafford et al, Mol. Pharmacol, 1996, 50, 670-678.
  • the procedure will suitably be carried out utilising cultures of stably transfected eukaryotic cells, typically of stably transfected mouse Ltk- fibroblast cells.
  • the compounds according to the present invention exhibit anxiolytic activity, as may be demonstrated by a positive response in the elevated plus maze and conditioned suppression of drinking tests (cf. Dawson et al, Psychopharmacology, 1995, 121, 109-117). Moreover, the compounds of the invention are substantially non-sedating, as may be confirmed by an appropriate result obtained from the response sensitivity (chain-pulling) test (cf. Bayley et al, J. Psychopharmacol, 1996, 10, 206-213). The compounds according to the present invention may also exhibit anticonvulsant activity. This can be demonstrated by the ability to block pentylenetetrazole-induced seizures in rats and mice, following a protocol analogous to that described by Bristow et al. in J. Pharmacol Exp. Ther.. 1996, 279, 492-501.
  • the compounds of the invention will ideally be brain-penetrant; in other words, these compounds will be capable of crossing the so-called "blood-brain barrier".
  • the compounds of the invention will be capable of exerting their beneficial therapeutic action following administration by the oral route.
  • compositions comprising one or more compounds of this invention in association with a pharmaceutically acceptable carrier.
  • these compositions are in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, auto-injector devices or suppositories; for oral, parenteral, intranasal, sublingual or rectal administration, or for administration by inhalation or insufflation.
  • a pharmaceutical carrier e.g.
  • a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a pharmaceutically acceptable salt thereof.
  • preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules.
  • This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of the active ingredient of the present invention.
  • Typical unit dosage forms contain from 1 to 100 mg, for example 1, 2, 5, 10, 25, 50 or 100 mg, of the active ingredient.
  • the tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action.
  • the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former.
  • the two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release.
  • a variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate.
  • the liquid forms in which the novel compositions of the present invention may be incorporated for administration orally or by injection include aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical vehicles.
  • Suitable dispersing or suspending agents for aqueous suspensions include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinyl-pyrrolidone or gelatin.
  • a suitable dosage level is about 0.01 to
  • the compounds may be administered on a regimen of 1 to 4 times per day.
  • the compounds of formula I as defined above may be prepared by a process which comprises reacting a compound of formula III with a compound of formula IV:
  • the leaving group L 1 is typically a halogen atom, especially chloro.
  • reaction between compounds III and IV is conveniently effected by stirring the reactants in a suitable solvent, typically -NTV-dimethyl- formamide, in the presence of a strong base such as sodium hydride.
  • a suitable solvent typically -NTV-dimethyl- formamide
  • the intermediates of formula III above may be prepared by reacting a compound of formula V with a substantially equimolar amount of a hydrazine derivative of formula VI:
  • the leaving group L 2 is typically a halogen atom, especially chloro.
  • the leaving groups L 1 and L 2 may be the same or different, but are suitably the same, preferably both chloro.
  • the reaction between compounds V and VI is conveniently effected by heating the reactants in the presence of a proton source such as triethylamine hydrochloride, typically at reflux in an inert solvent such as xylene or 1,4-dioxane.
  • the intermediates of formula III above may be prepared by reacting a hydrazine derivative of formula VII with an aldehyde derivative of formula VIII:
  • the reaction between compounds VII and VIII is conveniently effected under acidic conditions, for example in the presence of a mineral acid such as hydrochloric acid. Cyclization of the resulting Schiffs base intermediate may then conveniently be carried out by treatment with lead(IV) acetate in acetic acid or with iron(III) chloride in a suitable solvent, e.g. an alcoholic solvent such as ethanol, at an elevated temperature, typically at a temperature in the region of 60-70°C.
  • a suitable solvent e.g. an alcoholic solvent such as ethanol
  • the intermediates of formula VII above may be prepared by reacting the appropriate compound of formula V as defined above with hydrazine hydrate, typically in 1,4-dioxane at the reflux temperature of the solvent; followed, if necessary, by separation of the resulting mixture of isomers bv conventional means.
  • the intermediates of formula III above may be prepared by reacting the hydrazine derivative of formula VII as defined above with a compound of formula IX:
  • Suitable values for the reactive carboxylate moiety Q include esters, for example C ⁇ - 4 alkyl esters; acid anhydrides, for example mixed anhydrides with C ⁇ -4 alkanoic acids; acid halides, for example acid chlorides; and acylimidazoles.
  • Q represents an acid chloride moiety.
  • reaction between compounds VII and IX is conveniently effected under basic conditions, e.g. in the presence of triethylamine, suitably in an inert solvent such as diethyl ether, and typically at a temperature in the region of 0°C.
  • Cyclization of the resulting compound of formula X may then conveniently be carried out by treatment with 1,2-dibromo- 1,1,2,2- tetrachloroethane and triphenylphosphine, in the presence of a base such as triethylamine, suitably in an inert solvent such as acetonitrile, and typically at a temperature in the region of 0°C.
  • the compounds of formula I as defined above may be prepared by a process which comprises reacting a compound of formula XI (or its l,2,4-triazolo[4,3-b]pyridazin-6-one tautomer) with a compound of formula XII:
  • the leaving group L 3 is suitably a halogen atom, typically chloro or bromo.
  • the reaction between compounds XI and XII is conveniently effected by stirring the reactants in a suitable solvent, typically N,N- dimethylformamide, in the presence of a strong base such as sodium hydride.
  • the intermediates of formula XI above may conveniently be prepared by reacting a compound of formula III as defined above with an alkali metal hydroxide, e.g. sodium hydroxide.
  • the reaction is conveniently effected in an inert solvent such as aqueous 1,4-dioxane, ideally at the reflux temperature of the solvent.
  • the compounds of formula I as defined above may be prepared by a process which comprises reacting a compound of formula Z-CO2H with a compound of formula XIII:
  • reaction is conveniently carried out in a suitable solvent, for example water or aqueous acetonitrile, optionally under acidic conditions, e.g. using sulphuric acid, typically at an elevated temperature.
  • a suitable solvent for example water or aqueous acetonitrile
  • acidic conditions e.g. using sulphuric acid
  • the compounds of formula I as defined above may be prepared by a process which comprises reacting a compound of formula XIV with a compound of formula XV:
  • M represents -B(OH) 2 or -Sn(Alk) 3 in which Alk represents a CI-G alkyl group, typically . ⁇ -butyl, and L 4 represents a suitable leaving group; in the presence of a transition metal catalyst.
  • the leaving group L 4 is suitably a halogen atom, e.g. bromo.
  • a suitable transition metal catalyst of use in the reaction between compounds XIV and XV comprises dichlorobis(triphenylphosphine)- palladium(II) or tetrakis(triphenylphosphine)palladium(0).
  • reaction between compounds XIV and XV is conveniently effected in an inert solvent such as N,iV-dimethylformamide, typically at an elevated temperature.
  • the intermediates of formula XIV may be prepared by reacting a compound of formula IV as defined above with a compound of formula XVI:
  • the compounds of formula I wherein R 4 represents trifluoromethyl and R 3 is hydrogen may be prepared by a process which comprises reacting a compound of formula XVII with the hydrazide of formula XVIII:
  • reaction is conveniently accomplished by treating compound XVII with sodium methoxide in methanol, neutralising with acetic acid, adding hydrazide XVIII and heating in a solvent such as methanol at a temperature typically in the region of 60°C.
  • the intermediates of formula XVII above may be prepared by reacting the appropriate compound of formula XI (or its l,2,4-triazolo[4,3- b]pyridazin-6-one tautomer) as defined above with a compound of formula 3 -CH2CN, wherein L 3 is as defined above, under conditions analogous to those described above for the reaction between compounds XI and XII.
  • the hydrazide of formula XVIII above may be prepared as described in Magn. Reson. Chem., 1990, 28, 331-336. Where they are not commercially available, the starting materials of formula IV, V, VI, VIII, IX, XII, XV and XVI may be prepared by methods analogous to those described in the accompanying Examples, or by standard methods well known from the art.
  • any compound of formula I initially obtained from any of the above processes may, where appropriate, subsequently be elaborated into a further compound of formula I by techniques known from the art.
  • a compound of formula I initially obtained wherein R 3 is hydrogen may be converted into a corresponding compound wherein R 3 represents methyl or ethyl by standard alkylation procedures, typically by treatment with iodomethane or iodoethane in the presence of sodium hydride and N,N-dimethyl- formamide.
  • a compound of formula I initially obtained wherein R 4 represents a group of formula -CHtaOR 3 and R a represents tert- butyldimethylsilanyl may be converted into the corresponding compound wherein R a is hydrogen using conventional protodesilylation procedures, typically by heating in ethanolic hydrochloric acid.
  • the resulting compound of formula I wherein R 4 represents -CH2OH may be converted into the corresponding compound wherein R 4 represents -CH 2 OR a and R a is methyl by methylating with iodomethane in the presence of sodium hydride and N,iV-dimethylformamide.
  • a compound of formula I wherein R 4 represents -CH2OH may be converted into the corresponding compound wherein R 4 represents chloromethyl by stirring in phosphorus oxychloride.
  • a compound of formula I wherein R 4 represents -CH2OH may be converted into the corresponding compound wherein R 4 represents -CH-2NR b R c in a two-step process which comprises oxidising the -CH2OH moiety to -CHO by treatment with oxalyl chloride and dimethylsulphoxide in the presence of triethylamine and dichloromethane; followed by treatment of the resulting aldehyde derivative with the appropriate amine of formula H-NR b R c in the presence of a reducing agent such as sodium cyanoborohydride.
  • a reducing agent such as sodium cyanoborohydride.
  • a compound of formula I wherein R 4 represents chloromethyl may be converted into a corresponding compound wherein R 4 represents -CH2NR b R c by treatment with the appropriate amine of formula H-N R b R c , typically with heating in the presence of sodium hydride and N,-V-dimethylacetamide.
  • any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene & P.G.M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 1991.
  • the protecting groups may be removed at a convenient subsequent stage using methods known from the art.
  • the compounds in accordance with this invention potently inhibit the binding of [ 3 H]-flumazenil to the benzodiazepine binding site of human GABAA receptors containing the ⁇ 2 or ⁇ 3 subunit stably expressed in Ltk- cells.
  • PBS Phosphate buffered saline
  • Assay buffer 10 mM KH 2 PO 4 , 100 mM KC1, pH 7.4 at room temperature.
  • Supernatant is removed from cells.
  • PBS approximately 20 ml
  • the cells are scraped and placed in a 50 ml centrifuge tube. The procedure is repeated with a further 10 ml of PBS to ensure that most of the cells are removed.
  • the cells are pelleted by centrifuging for 20 min at 3000 rpm in a benchtop centrifuge, and then frozen if desired. The pellets are resuspended in 10 ml of buffer per tray (25 cm x 25 cm) of cells.
  • Assay Can be carried out in deep 96-well plates or in tubes. Each tube contains:
  • Assays are incubated for 1 hour at 40°C, then filtered using either a Tomtec or Brandel cell harvester onto GF/B filters followed by 3 x 3 ml washes with ice cold assay buffer. Filters are dried and counted by liquid scintillation counting. Expected values for total binding are 3000-4000 dpm for total counts and less than 200 dpm for non-specific binding if using liquid scintillation counting, or 1500-2000 dpm for total counts and less than 200 dpm for non-specific binding if counting with meltilex solid scintillant. Binding parameters are determined by non-linear least squares regression analysis, from which the inhibition constant Ki can be calculated for each test compound.
  • 3,6-Dichloro-4-phenylpyridazine (2.9 g, 13 mmol), benzoic hydrazide (1.9 g, 21 mmol) and triethylammonium chloride (2.0 g, 14 mmol) were heated together at reflux in xylene (150 ml) for three days. More benzoic hydrazide (0.88 g, 6.5 mmol) was added and the mixture was heated as before for another day.
  • the solution was diluted with water (70 ml) and saturated aqueous sodium hydrogen carbonate was added until the pH was approximately 8. The solution was then washed with dichloromethane (3 x 50 ml). The organic layers were combined, washed with saturated aqueous sodium chloride (50 ml), dried (MgSO 4 ) and concentrated in vacuo.
  • 6-Chloro-3,7-diphenyl-l,2,4-triazolo[4,3-b]pyridazine (0.11 g, 0.35 mmol) was added and the mixture was stirred as before for 5 min. Water (50 ml) was added and the resultant precipitate was filtered off, and was then purified by flash chromatography (silica gel, 0-5% MeOH/CH2Cl 2 ).
  • N-dime thylamine To oxalyl chloride (63 ⁇ l, 92 mg, 0.73 mmol) in dichloromethane (15 ml) was added DMSO (110 ⁇ l, 1.5 mmol) with stirring at -78°C, and the resultant solution was stirred at -78°C under nitrogen for 30 min.
  • sodium hydride (60% dispersion in mineral oil; 88 mg, 2.2 mmol) and the resultant slurry was stirred at room temperature under nitrogen for 90 min.
  • Example 6 except using morpholine instead of dimethylamine hydrochloride, and dissolving the free base in methanolic hydrogen chloride prior to recrystallisation.
  • Data for the title compound * ⁇ NMR (360 MHz, DMSO-de) ⁇ 1.94 (4H, m), 3.63 (4H, m), 3.83 (8H, br m), 3.97 (3H, s), 4.40 (2H, s), 5.76 (2H, s), 6.83 (IH, s), 7.64 (3H, m), 8.27 (2H, m); MS (ES + ) m/e 476 [MH + ], 239 [MH + ]/2.
  • CDCI3 ⁇ 3.51 (4H, t, J 12 Hz), 4.44 (IH, s), 7.16-7.32 (6H, m), 7.42 (4H, m).
  • Example 6 but using 3,3-difluoroazetidine hydrochloride instead of dimethylamine hydrochloride.
  • Data for the title compound *H NMR (360 MHz, CDC1 3 ) ⁇ 1.96 (4H, m), 3.44 (4H, m), 3.75 (4H, t, J 12 Hz), 3.84 (2H, s), 3.95 (3H, s), 5.55 (2H, s), 6.69 (IH, s), 7.49 (3H, m), 8.30 (2H, m); MS (ES + ) m/e 463 [M-F] + .
  • Example 6 but using pyrrolidine instead of dimethylamine hydrochloride.
  • Data for the title compound ⁇ NMR (400 MHz, DMSO-de) ⁇ 1.81 (2H, m), 1.92 (6H, m), 3.09 (2H, m), 3.40 (2H, m), 3.56 (4H, m), 3.96 (3H, s), 4.46 (2H, s), 5.74 (2H, s), 6.86 (IH, s), 7.59 (3H, m), 8.25 (2H, m); MS (ES) m/e 460 [MH] + , 230 [MH + ]/2.

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Abstract

L'invention porte sur une classe de dérivés substitués de la 1,2,4-triazolo[4,3-b]pyridazine présentant un cycle phényle en position 3, et un fragment triazolyl-méthoxy à substitution C en position 6. Ces dérivés sont des liants sélectifs des récepteurs du GABAA présentant en particulier une forte affinité pour des sous-unités α2 et/ou α3, et s'avérant de ce fait intéressants pour le traitement et/ou la prévention de troubles du SNC dont l'anxiété et les convulsions.
PCT/GB2000/000308 1999-02-11 2000-02-02 Derives de la triazolo-pyridazine, liants des recepteurs du gaba Ceased WO2000047582A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
AU23065/00A AU2306500A (en) 1999-02-11 2000-02-02 Triazolo-pyridazine derivatives as ligands for gaba receptors
EP00901765A EP1150983A1 (fr) 1999-02-11 2000-02-02 Derives de la triazolo-pyridazine, liants des recepteurs du gaba
JP2000598502A JP2002536449A (ja) 1999-02-11 2000-02-02 Ｇａｂａレセプターに対するリガンドとしてのトリアゾロ−ピリダジン誘導体
CA002362400A CA2362400A1 (fr) 1999-02-11 2000-02-02 Derives de la triazolo-pyridazine, liants des recepteurs du gaba

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9903119.7A GB9903119D0 (en) 1999-02-11 1999-02-11 Therapeutic agents
GB9903119.7 1999-02-11

Publications (1)

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WO2000047582A1 true WO2000047582A1 (fr) 2000-08-17

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EP (1) EP1150983A1 (fr)
JP (1) JP2002536449A (fr)
AU (1) AU2306500A (fr)
CA (1) CA2362400A1 (fr)
GB (1) GB9903119D0 (fr)
WO (1) WO2000047582A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005039569A1 (fr) * 2003-10-18 2005-05-06 Bayer Healthcare Ag Derives de 2-(phenylmethyl)thio-4-phenyl-4h-1,2,4-triazole substitues en 5 et composes associes utilises en tant que gaba-agonistes dans le traitement de l'incontinence urinaire et des maladies associees
US6958334B2 (en) 2001-04-10 2005-10-25 Merck & Co., Inc. Inhibitors of Akt activity
US6960584B2 (en) 2001-04-10 2005-11-01 Merck & Co., Inc. Inhibitors of Akt activity
WO2005116014A1 (fr) 2004-05-12 2005-12-08 Pfizer Products Inc. Derives de proline et leur utilisation en tant qu'inhibiteurs de la dipeptidyl-peptidase iv
US7015224B2 (en) * 2001-09-20 2006-03-21 Merck Sharp & Dohme Ltd. 7-Tert-butyl-3-(2-fluorophenyl)-6-(2H-(1,2,4)triazol-3-ylmethoxy)-(1,2,4)triazolo (4,3b) pyridazine for the treatment of anxiety and convulsions
US7098208B2 (en) 2001-04-10 2006-08-29 Merck & Co., Inc. Inhibitors of Akt activity
WO2009061879A1 (fr) 2007-11-09 2009-05-14 Smithkline Beecham Corporation Inhibiteurs de la peptide déformylase
WO2017129801A1 (fr) * 2016-01-27 2017-08-03 Universität Zürich Utilisation de modulateurs des récepteurs gabaa pour le traitement des démangeaisons

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998004559A2 (fr) * 1996-07-25 1998-02-05 Merck Sharp & Dohme Limited Derives de triazolo-pyridazine substitues servant de ligands pour recepteurs de gaba

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998004559A2 (fr) * 1996-07-25 1998-02-05 Merck Sharp & Dohme Limited Derives de triazolo-pyridazine substitues servant de ligands pour recepteurs de gaba

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6958334B2 (en) 2001-04-10 2005-10-25 Merck & Co., Inc. Inhibitors of Akt activity
US6960584B2 (en) 2001-04-10 2005-11-01 Merck & Co., Inc. Inhibitors of Akt activity
US7098208B2 (en) 2001-04-10 2006-08-29 Merck & Co., Inc. Inhibitors of Akt activity
US7015224B2 (en) * 2001-09-20 2006-03-21 Merck Sharp & Dohme Ltd. 7-Tert-butyl-3-(2-fluorophenyl)-6-(2H-(1,2,4)triazol-3-ylmethoxy)-(1,2,4)triazolo (4,3b) pyridazine for the treatment of anxiety and convulsions
WO2005039569A1 (fr) * 2003-10-18 2005-05-06 Bayer Healthcare Ag Derives de 2-(phenylmethyl)thio-4-phenyl-4h-1,2,4-triazole substitues en 5 et composes associes utilises en tant que gaba-agonistes dans le traitement de l'incontinence urinaire et des maladies associees
EP2116541A1 (fr) 2004-05-12 2009-11-11 Pfizer Products Incorporated Dérivés de proline et leur utilisation en tant qu'inhibiteurs de la dipeptidyl-peptidase IV
WO2005116014A1 (fr) 2004-05-12 2005-12-08 Pfizer Products Inc. Derives de proline et leur utilisation en tant qu'inhibiteurs de la dipeptidyl-peptidase iv
WO2009061879A1 (fr) 2007-11-09 2009-05-14 Smithkline Beecham Corporation Inhibiteurs de la peptide déformylase
WO2017129801A1 (fr) * 2016-01-27 2017-08-03 Universität Zürich Utilisation de modulateurs des récepteurs gabaa pour le traitement des démangeaisons
US10786513B2 (en) 2016-01-27 2020-09-29 Universitat Zurich Use of GABAA receptor modulators for treatment of itch
US11529359B2 (en) 2016-01-27 2022-12-20 Universitat Zurich Use of GABAA receptor modulators for treatment of itch
AU2017213154B2 (en) * 2016-01-27 2023-02-02 Universität Zürich Use of GABAA receptor modulators for treatment of itch
US12433898B2 (en) 2016-01-27 2025-10-07 Universitat Zurich Use of GABAA receptor modulators for treatment of itch

Also Published As

Publication number Publication date
AU2306500A (en) 2000-08-29
CA2362400A1 (fr) 2000-08-17
EP1150983A1 (fr) 2001-11-07
JP2002536449A (ja) 2002-10-29
GB9903119D0 (en) 1999-04-07

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