Substituted tetrahydroisoquinoline derivatives as D1 positive allosteric modulators

Abstract

The present invention relates to a compound according to formula (I), [Formula 1] JPEG2022537994000020.jpg5383 It is a positive allosteric modulator of D1 and is therefore useful as a pharmaceutical for the treatment of diseases in which the D1 receptor is involved.

Description

[Technical field]

[0001] The present invention relates to tetrahydroisoquinoline derivatives and their use in therapy, in particular to pharmacologically active substituted tetrahydroisoquinoline derivatives.

[0002] The compounds act as D1 positive allosteric modulators and are therefore useful as therapeutic agents for diseases in which the D1 receptor is involved. [Background technology]

[0003] Dopamine, a monoamine, acts through two GPCR families to regulate motor functions, reward mechanisms, cognitive processes, and other physiological functions. Specifically, dopamine acts on neurons through D1-like receptors, including dopamine D1 and D5 (which mainly bind to Gs G proteins, thereby promoting the production of cAMP), and D2-like receptors, including D2, D3, and D4 receptors (which bind to Gi / q G proteins, inhibiting the production of cAMP). These receptors are widely expressed in various parts of the brain. In particular, D1 receptors are involved in many physiological and behavioral processes. For example, D1 receptors are involved in synaptic plasticity, cognitive functions, goal-directed motor functions, as well as reward processes. D1 receptors are involved in a variety of physiological and neurological processes and may therefore be involved in a variety of diseases, including the cognitive and negative symptoms of schizophrenia, cognitive impairment associated with classical antipsychotic treatment, impulsivity, attention-hyperactivity disorder (ADHD), Parkinson's disease and related movement disorders, dystonia, Huntington's disease, dementia with Lewy bodies, Alzheimer's disease, age-related cognitive decline, mild cognitive impairment (MCI), drug addiction, sleep disorders, and apathy.

[0004] The development of orally bioavailable small molecule compounds targeting the D1 receptor has proven challenging. D1 agonists developed to date have generally featured a catechol moiety, which has limited their clinical use to invasive treatments. Also, the high homology of ligand-binding sites between dopamine receptor subtypes (e.g., dopamine D1 and D5) has made it difficult to obtain sufficient selectivity. D1 agonists are also associated with potentially limiting side effects, including but not limited to dyskinesia and hypotension.

[0005] Therefore, there is a need to design new drugs that modulate the D1 receptor. Identification of allosteric modulators of GPCRs has attracted great interest as a tool to understand receptor mechanisms and as potential therapeutic agents. GPCRs are the largest family of receptors present on the cell surface, and many marketed drugs directly activate or block signaling pathways mediated by these receptors. However, for some GPCRs (e.g., peptide receptors), small molecules have proven difficult to develop and to obtain sufficient selectivity due to the high homology of ligand binding sites between subtypes (e.g., dopamine D1 and D5, D2 and D3, etc.). Therefore, much of the drug research has shifted to identifying small molecules that target sites distinct from the orthosteric natural agonists. Ligands that bind to these sites alter the conformation of the GPCR and allosterically regulate the function of the receptor. Allosteric ligands have diverse activities, including the ability to enhance (positive allosteric modulators: PAMs) or attenuate (negative allosteric modulators: NAMs) the action of endogenous ligands by affecting affinity and / or efficacy. In addition to subtype selectivity, allosteric modulators may have other potential advantages from a drug discovery perspective, such as the lack of direct effects or intrinsic efficacy, only enhancing the effect of native transmitters where and when they are released, less tendency to induce desensitization resulting from constant exposure to agonists, and less tendency to induce target-related side effects.

[0006] The compounds according to the invention are D1 positive allosteric modulators (D1 PAMs) since they potentiate the effect of D1 agonists or endogenous ligands on the D1 receptor via an allosteric mechanism.

[0007] The compound according to the present invention is a D1 PAM and is therefore useful for treating and / or preventing diseases and disorders involving D1 receptors, such as cognitive and negative symptoms in schizophrenia, cognitive impairment associated with neuroleptic therapy, mild cognitive impairment (MCI), impulsivity, attention deficit hyperactivity disorder (ADHD), Parkinson's disease and other movement disorders, dystonia, Parkinson's disease dementia, Huntington's disease, dementia with Lewy bodies, Alzheimer's disease, drug addiction, sleep disorder, apathy, traumatic spinal cord injury, and neuropathic pain.

[0008] International patent application WO2013 / 051869A1 discloses certain 3,4-dihydro-1H-isoquinolin-2-yl derivatives that are NK2 antagonists.

[0009] International patent application WO2008 / 109336A1 discloses certain tetrahydroisoquinoline compounds that are modulators of the histamine H3 receptor.

[0010] International patent application WO2014 / 193781A1 discloses certain 3,4-dihydroisoquinolin-2(1H)-yl derivatives which are believed to be useful for the treatment of cognitive impairment associated with Parkinson's disease or schizophrenia.

[0011] International patent application WO2016 / 055479 discloses substituted 3,4-dihydroisoquinolin-2(1H)-yl derivatives and analogues thereof that are useful for the treatment of diseases in which the D1 receptor plays a role.

[0012] International patent application WO2019 / 204418 discloses certain pyrazo-tetrahydroisoquinoline derivatives which are D1 positive allosteric modulators and which are believed to be useful in the treatment of Parkinson's disease and other movement disorders, Alzheimer's disease, schizophrenia and attention deficit hyperactivity disorder (ADHD). Summary of the Invention [Problem to be solved by the invention]

[0013] However, there is a need to develop potent D1 positive allosteric modulators that combine excellent pharmacokinetic and pharmacodynamic properties while reducing the side effects traditionally seen with treatment using selective D1 agonists, such as motor and cognitive disorders. [Means for solving the problem]

[0014] The present invention relates to 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[5-[2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl] esters of formula (I). Ta Non [ka] or a pharma- ceutically acceptable salt thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Compounds according to the present invention are encompassed within the general scope of co-pending international patent application WO2016 / 055479, which, however, does not specifically disclose the compound of formula (I) as depicted above, or a pharma-ceutically acceptable salt thereof.

[0016] The present invention also provides a compound of formula (I) or a pharma- ceutically acceptable salt thereof as hereinbefore defined for use in therapy.

[0017] In another aspect, the present invention also provides a compound of formula (I) as defined above, or a pharma- ceutically acceptable salt thereof, for use in the treatment and / or prevention of diseases and / or disorders in which the D1 receptor plays a role.

[0018] In another aspect, the present invention provides a compound of formula (I) as defined above, or a pharma- ceutically acceptable salt thereof, for use in the treatment and / or prophylaxis of cognitive and negative symptoms in schizophrenia, cognitive impairment associated with neuroleptic therapy, mild cognitive impairment (MCI), impulsivity, attention deficit hyperactivity disorder (ADHD), Parkinson's disease and other movement disorders, dystonia, Parkinson's dementia, Huntington's disease, dementia with Lewy bodies, Alzheimer's disease drug dependence, sleep disorders, apathy, traumatic spinal cord injury or neuropathic pain.

[0019] In a particular embodiment of this aspect, the invention provides a compound of formula (I) as defined above, or a pharma- ceutically acceptable salt thereof, for use in the treatment of cognitive and negative symptoms in Parkinson's disease and other movement disorders, Alzheimer's disease, or schizophrenia.

[0020] Thus, in one particular aspect, the present invention provides a compound of formula (I) as defined above, or a pharma- ceutically acceptable salt thereof, for use in the treatment of Parkinson's disease and other movement disorders.

[0021] In a further aspect, the present invention provides the use of a compound of formula (I) or a pharma- ceutically acceptable salt thereof as defined above for the manufacture of a medicament useful for the treatment and / or prevention of diseases and / or disorders in which the D1 receptor plays a role.

[0022] In another further aspect, the present invention provides the use of a compound of formula (I) or a pharma- ceutically acceptable salt thereof as defined above for the manufacture of a medicament useful for the treatment and / or prevention of cognitive and negative symptoms in schizophrenia, cognitive impairment associated with neuroleptic therapy, mild cognitive impairment (MCI), impulsivity, attention deficit hyperactivity disorder (ADHD), Parkinson's disease and other movement disorders, dystonia, Parkinson's dementia, Huntington's disease, dementia with Lewy bodies, Alzheimer's disease, drug addiction, sleep disorders, apathy, traumatic spinal cord injury, neuropathic pain.

[0023] In a particular embodiment of this aspect, the invention provides the use of a compound of formula (I) as defined above or a pharma- ceutically acceptable salt thereof for the manufacture of a medicament useful for the treatment of cognitive and negative symptoms in Parkinson's disease and other movement disorders, Alzheimer's disease, or schizophrenia.

[0024] In one particular aspect, the present invention provides the use of a compound of formula (I) or a pharma- ceutically acceptable salt thereof as defined above for the manufacture of a medicament useful for the treatment of Parkinson's disease and other movement disorders.

[0025] The present invention also provides a method for the treatment and / or prevention of diseases in which the administration of a D1 positive allosteric modulator is indicated, comprising administering to a patient in need of such treatment an effective amount of a compound of formula (I) as defined above or a pharma- ceutically acceptable salt thereof.

[0026] In another aspect, the present invention provides a method for the treatment and / or prevention of cognitive and negative symptoms in schizophrenia, cognitive impairment associated with neuroleptic treatment, mild cognitive impairment (MCI), impulsivity, attention deficit hyperactivity disorder (ADHD), Parkinson's disease and other movement disorders, dystonia, Parkinson's dementia, Huntington's disease, dementia with Lewy bodies, Alzheimer's disease, drug addiction, sleep disorders, apathy, traumatic spinal cord injury or neuropathic pain, 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 pharma- ceutically acceptable salt thereof.

[0027] In a particular embodiment of this aspect, the invention provides a method for the treatment of cognitive and negative symptoms in Parkinson's disease and other movement disorders, Alzheimer's disease, or schizophrenia, 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 pharma- ceutically acceptable salt thereof.

[0028] In one particular aspect, the present invention provides a method for the treatment of Parkinson's disease and other movement disorders, comprising administering to a patient in need of such treatment an effective amount of a compound of formula (I) as defined above or a pharma- ceutically acceptable salt thereof.

[0029] When used in medicine, the salt of the compound of formula (I) will be a pharmaceutically acceptable salt. However, other salts may be useful in the preparation of the compound of formula (I) or its pharmaceutically acceptable salt. The standard principles underlying the selection and preparation of pharmaceutically acceptable salts are described, for example, in Handbook of Pharmaceutical Salts: Properties, Selection and Use, ed. P.H. Stahl & C.G. Wermuth, Wiley-VCH, 2002. Suitable pharmaceutically acceptable salts of the compound of formula (I) include, for example, the acid addition salts that can be formed by mixing a solution of the compound of formula (I) with a solution of a pharmaceutically acceptable acid.

[0030] It is to be understood that the individual atoms in formula (I) and the formulae below may in fact be present in any of their naturally occurring isotopic forms, with the most abundant isotopes being preferred. Similarly, the individual hydrogen atoms in formula (I) and the formulae below may be present in any of their naturally occurring isotopic forms, with the most abundant isotopes being preferred. 1 H, 2 H (deuterium) or 3 H (tritium) atoms, preferably 1 H. Similarly, each carbon atom in formula (I) or in the formulae shown below may be present as: 12 C. 13 C or 14 C atom, preferably 12 It may also exist as C.

[0031] The present invention includes within its scope solvates of the compounds of formula (I) above. Such solvates may be formed with common organic solvents or with water.

[0032] The present invention also includes within its scope co-crystals of the compounds of formula (I) above. The technical term "co-crystal" is used to describe the presence of neutral molecular components in a crystalline compound in a definite stoichiometric ratio. The preparation of pharmaceutical co-crystals allows for the modification of the crystalline form of a pharmaceutical active ingredient, thereby altering its physicochemical properties without impairing its intended biological activity (see Pharmaceutical Salts and Co-crystals, ed. J. Wouters & L. J. Wouters & L. Quere, RSC Publishing, 2012).

[0033] The compounds according to the present invention may exist in different polymorphic forms. Although not explicitly shown in the above formula, such forms are intended to be included within the scope of the present invention.

[0034] The present invention also includes within its scope prodrug forms of the compounds of formula (I) and its various subscopes and subgroups.

[0035] The compound of formula (I) contains two asymmetric centers, and therefore may have diastereomers.It should be understood that the present invention extends to the use of all such diastereoisomers and their mixtures in any ratio.Therefore, formula (I) is intended to represent all individual stereoisomers and their possible mixtures, unless otherwise stated or indicated.

[0036] In a particular aspect of the invention, there is provided a compound of formula (IA) 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[(1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl] ester Ta Non [ka] or a pharma- ceutically acceptable salt thereof is provided.

[0037] Of course, activity in the above mentioned therapeutic indications and diseases can be determined by conducting appropriate clinical trials in a manner known to those skilled in the art for the specific indication and / or in clinical trial design in general.

[0038] For the treatment of diseases, the compound of formula (I) or a pharma- ceutically acceptable salt thereof may be used in an effective amount per day and administered in the form of a pharmaceutical composition.

[0039] Thus, the present invention also provides a pharmaceutical composition comprising a compound of formula (I) above, or a pharma- ceutically acceptable salt thereof, in association with one or more pharma- ceutically acceptable carriers.

[0040] To prepare pharmaceutical compositions according to the invention, one or more compounds of formula (I) or pharma- ceutically acceptable salts thereof are intimately admixed with a pharmaceutical diluent or carrier according to conventional pharmaceutical compounding techniques known to those skilled in the art.

[0041] Suitable diluents or carriers can take a variety of forms depending on the desired route of administration, including oral, rectal, parenteral, or intranasal.

[0042] Pharmaceutical compositions according to the invention can be administered, for example, orally, parenterally, ie, intravenously, intramuscularly, subcutaneously, intrathecally, by inhalation, or intranasally.

[0043] Pharmaceutical compositions suitable for oral administration may be solid or liquid and may be in the form of, for example, tablets, pills, dragees, gelatin capsules, solutions, syrups, chewing gums, or the like.

[0044] For this purpose, the active ingredient can be mixed with an inert diluent or a non-toxic pharma- ceutically acceptable carrier such as starch, lactose, etc. Optionally, these pharmaceutical compositions can also contain a binder such as microcrystalline cellulose, gum tragacanth, gelatin, a disintegrating agent such as alginic acid, a lubricant such as magnesium stearate, a glidant such as colloidal silicon dioxide, a sweetener such as sucrose, saccharin, or a coloring agent, or a flavoring agent such as peppermint, methyl salicylate, etc.

[0045] The present invention also contemplates compositions that can release the active substance in a controlled manner. Pharmaceutical compositions that can be used for parenteral administration are in conventional forms such as aqueous or oily solutions or suspensions, and are generally contained in ampoules, disposable syringes, glass or plastic vials, or infusion containers.

[0046] In addition to the active ingredient, these solutions and suspensions may optionally contain a sterile diluent such as water for injection, physiological saline, oil, polyethylene glycol, glycerin, propylene glycol or other synthetic solvent; an antibacterial agent such as benzyl alcohol; an antioxidant such as ascorbic acid or sodium bisulfite; a chelating agent such as ethylenediaminetetraacetic acid; a buffer such as acetate, citrate or phosphate; or an osmotic regulator such as sodium chloride or dextrose.

[0047] These medicines are prepared by methods routinely used by pharmacists.

[0048] The amount of the compound used in the present invention required to prevent or treat a particular condition will vary depending on the compound selected and the condition of the patient being treated, but generally the daily dosage may range from 0.05 to 3000 mg, with parenteral compositions usually ranging from 0.5 mg to 1000 mg.

[0049] The compound of the present invention or its pharma- ceutically acceptable salt may be administered alone (monotherapy) or in combination with L-dopa (combination therapy). The compound of formula (I) of the present invention or its pharma- ceutically acceptable salt may be useful for treating dyskinesia associated with administration of L-dopa, alone or in combination with a portion of the dose of L-dopa required to improve the patient's movement disorder. For example, when the compound of formula (I) of the present invention is used together with a portion of the dose of L-dopa administered to the patient or used alone instead of L-dopa, the compound of formula (I) of the present invention is believed to be effective against movement disorders without inducing troublesome dyskinesia. Thus, the compound of the present invention is believed to be useful for treating movement disorders and levodopa-induced dyskinesia (LID).

[0050] Thus, in one particular aspect, the present invention also provides compounds of formula (I) that are useful for the treatment of levodopa-induced dyskinesia (LID).

[0051] The compounds according to the present invention or pharma- ceutically acceptable salts thereof may be administered alone or in combination with other pharma- ceutical active ingredients.

[0052] Compounds of formula (I) may be prepared by a process comprising reacting an intermediate of formula (II) with an intermediate of formula (III). [ka]

[0053] The hydrochloride salt of intermediate (III) is then reacted with an intermediate of formula (II) in the presence of (2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) or other coupling agent known to one skilled in the art, in a suitable solvent such as dimethylformamide, using an excess of a base, such as N,N-diisopropylethylamine.

[0054] The intermediate of formula (III) may be prepared by a process comprising the reaction of an intermediate of formula (IV), in which Y represents a halogen, for example bromo, with commercially available fluoroacetone. [ka]

[0055] This reaction is conveniently carried out according to methods known to those skilled in the art, for example in the presence of n-BuLi in a suitable solvent such as tetrahydrofuran at low temperature by metal-halogen exchange.

[0056] In the above reactions, the amino group of the intermediates of formula (III) and (IV) is generally first protected with a suitable protecting group, such as a tert-butoxycarbonyl group, according to methods known to those skilled in the art, prior to reacting with further reagents.

[0057] The intermediate of formula (IIIa) may be prepared by a process comprising reaction of an intermediate of formula (V). [ka] wherein Y is as defined above.

[0058] The reaction is conveniently carried out in the presence of a suitable reducing agent, such as sodium borohydride, in a suitable solvent, such as ethanol, at reduced temperature according to methods known to those skilled in the art.

[0059] An intermediate of formula (V) may be prepared by a process comprising reaction of an intermediate of formula (VI). [ka] wherein Y is as defined above.

[0060] The reaction is preferably carried out in a suitable solvent, such as methanol, in the presence of sulfuric acid at room temperature.

[0061] Intermediates of formula (VI) can be prepared by a process involving reaction of commercially available intermediate (VII). [ka] wherein Y is as defined above.

[0062] The reaction is preferably carried out in the presence of oxalyl chloride using a suitable solvent such as dichloromethane at low temperature, followed by the addition of ferric chloride at room temperature.

[0063] The intermediate of formula (II) may be prepared by a multi-step process involving reaction of an intermediate of formula (VIII). [ka] During the ceremony R 1 is hydrogen, -CH2OH, -COOR a or Y as defined above. R 2 HA-COOR a Represents. R a is hydrogen or C 1‐6 Represents alkyl.

[0064] In the first stage, R 1 represents hydrogen, and R a The intermediate of formula (VIII), where represents methyl, is reacted with an oxidizing agent, such as m-chloroperbenzoic acid (m-CPBA), in a suitable solvent, such as dichloromethane, at low temperature to give the corresponding N-oxide.

[0065] In the second step, the N-oxide resulting from the first step is reacted with phosphorus oxybromide to give R 1 Let Y be the above defined value, and R a represents methyl to obtain the corresponding intermediate of formula (VIII).

[0066] In the third step, R1 The intermediate of formula (VIII), wherein Y represents Y as defined above, is reacted with carbon monoxide in the presence of a base, such as N,N-diisopropylethylamine, in the presence of a transition metal catalyst, such as 1,4-bis(diphenylphosphino)butane-palladium(II) chloride, to give R 1 GA-COOR a R a is methyl, to give the corresponding intermediate of formula (VIII). This reaction is preferably carried out at elevated temperature and pressure.

[0067] Next, the latter intermediate R 1 The ester group of is reduced to the corresponding alcohol, followed by R 2 to the corresponding carboxylic acid to give an intermediate of formula (II). This reaction is carried out according to methods well known to those skilled in the art and as further described in the accompanying Examples.

[0068] R 1 represents hydrogen, and R a Intermediates of formula (VIII), in which represents methyl, may be prepared analogously to the methods described in the accompanying examples or by standard methods known to those skilled in the art.

[0069] When any of the above-described processes for the preparation of compounds according to the invention results in a product mixture, the desired product can be separated therefrom at an appropriate stage by conventional methods, such as preparative HPLC or by column chromatography, for example on silica and / or alumina, in combination with a suitable solvent system.

[0070] If the above-mentioned processes for the preparation of the compounds according to the invention give rise to a mixture of stereoisomers, these isomers can be separated by conventional techniques. In particular, if it is desired to obtain a particular enantiomer of a compound of formula (I), this can be produced from the corresponding mixture of enantiomers using any suitable conventional procedure for separating enantiomers. For example, a diastereomeric derivative (e.g., a salt) can be produced by reacting a mixture of enantiomers of formula (I) (e.g., a racemate) with a suitable chiral compound (e.g., a chiral base). The diastereomers can then be separated by any method, such as crystallization, and the desired enantiomer can be recovered, such as by treatment with an acid if the diastereomer is a salt. In another separation process, a racemate of formula (I) can be separated using chiral HPLC. Furthermore, if necessary, a particular enantiomer can be obtained using a suitable chiral intermediate in one of the above-mentioned processes. A specific enantiomer can also be obtained by enantiospecific enzymatic biotransformation, e.g., ester hydrolysis with an esterase, followed by purification of only the enantiomerically pure hydrolyzed acid from the unreacted ester antipode. Chromatography, recrystallization, and other conventional separation procedures can also be used on intermediates or final products if it is desired to obtain a specific geometric isomer of the invention. Alternatively, the undesired enantiomer can be racemized to the desired enantiomer in the presence of acid or base, according to methods known to those skilled in the art or described in the accompanying examples.

[0071] During the above synthetic procedures it may be necessary and / or desirable to protect sensitive or reactive groups on any of the molecules involved. This can be achieved using conventional protecting groups such as those described in Protective Groups in Organic Chemistry, ed. J. F. W. MacOmie, Plenum Press, 1973; and T. W. Greene & P. ​​G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 3rd edition, 1999. The protecting groups may be removed at any convenient subsequent stage using methods known in the art.

[0072] The compounds of formula (I) according to the present invention are D1 positive allosteric modulators (D1 PAMs) since they do not directly activate the dopamine D1 receptor but enhance the action of D1 agonists or dopamine, the endogenous ligand for the D1 receptor, by an allosteric mechanism.

[0073] Dopamine and other D1 agonists by themselves directly activate the dopamine D1 receptor.

[0074] Assays are designed to measure the effects of compounds of the present invention in the absence of dopamine (the "activation assay") and in the presence of dopamine (the "potentiation assay").

[0075] Activation assays measured stimulation of cyclic adenosine monophosphate (cAMP) production in a homogeneous time-resolved fluorescent (HTRF) assay, with 100% activation defined as the maximal increase in cAMP with increasing concentrations of the endogenous agonist dopamine.

[0076] When tested, the compounds of formula (I) according to the examples lack significant direct agonist-like effects in that when present at a concentration of 10 μM, they produce less than about 20% activation (compared to the maximal response of dopamine).

[0077] The potentiation assay measures the ability of compounds to increase the cAMP levels produced by a low-threshold concentration of dopamine. The dopamine concentration used (EC20) is designed to give a 20% stimulation of the maximal response (100%) to increasing concentrations of dopamine. To measure this potentiation, compounds are incubated with increasing concentrations of dopamine at their EC20, and the potentiation is measured as an increase in cAMP production, and the concentration of compound that produces 50% of the potentiation of cAMP levels is determined.

[0078] When tested in the cAMP HTRF assay, compounds of formula (I) according to the examples were found to be D1 positive allosteric modulators, with pEC50 values ​​of greater than about 6.5.

[0079] GABA A Inhibition of the receptor is known to be closely related to seizures and epilepsy, so the development of compounds that are D1 positive allosteric modulators while simultaneously minimizing such effects is desirable.

[0080] When tested in the GABA-A receptor inhibition assay described herein, the compounds of formula (I) inhibited GABA A receptor activity measured at a concentration of 10 μM of the compound of formula (I). A It was shown that the receptor inhibition rate was approximately 20% or less.

[0081] A problem that may be encountered when developing therapeutic compounds is the ability of a particular compound to inhibit CYP450 enzymes. Inhibition of such enzymes may affect the exposure of such compounds and other compounds that may be co-administered with them to a patient, thereby altering their respective safety and efficacy. It is therefore desirable to develop compounds that minimize the potential for such inhibition.

[0082] The CYP450 inhibitory ability of the compounds of formula (I) according to the invention has been tested by measuring the potential reduction in CYP450 activity in human hepatocytes incubated with increasing concentrations of the compounds according to the invention.

[0083] When tested in the CYP3A4 inhibition assay at concentrations of 1 and 20 μM according to the protocol described in this patent application, the compounds of formula (I) according to the invention show less than about 40%, ideally less than about 30% inhibition.

[0084] When developing therapeutic compounds, it is important to know how they are excreted from the body after administration.

[0085] Clearance is an informative parameter because it is the volume of plasma (or blood) that is completely cleared of the compound of interest over time. It is usually expressed in ml / min / kg or L / h. By comparing this value with the physiological blood flow (e.g. hepatic blood flow), it is possible to assess whether the clearance is low, moderate or high.

[0086] Low clearance would require a lower dose and provide a longer duration of action, depending on the volume of distribution, whereas high clearance would require a higher dose and provide a shorter duration of action, depending on the volume of distribution.

[0087] Typically, clearance is assessed using hepatocyte cultures and scaling calculations, following the protocol described herein, assuming that the primary route of excretion is metabolic. Intrinsic clearance assessed from hepatocytes is calculated as µl / min / 10 6 Represented by cells.

[0088] When tested in the clearance assay described herein, the compounds of formula (I) according to the invention advantageously have a clearance rate of about 10 μl / min / 10 6 Showing subcellular clearance.

[0089] cAMP HTRF assay The specific conditions under which the compounds were tested are given below.

[0090] a. Method D1 Cell culture Cells were cultured at 37°C in a humidified atmosphere of 5% CO2. Cells were grown in DMEM-F12 + GlutaMAX™-I medium (GIBCO®, Invitrogen, Merelbeke, Belgium) containing 10% fetal bovine serum (BioWhittaker®, Lonza, Verviers, Belgium), 400 μg / mL geneticin (GIBCO®), 100 IU / mL penicillin and 100 IU / mL streptomycin (Pen-Strep solution, BioWhittaker®). LMtk (Ltk-) mouse fibroblasts expressing dopamine D1 receptors (BioSignal Inc, Montreal, Canada, now Perkin Elmer) were used as they have been shown to efficiently couple and give robust functional responses (Watts et al., 1995).

[0091] b. cAMP assay Measurement of intracellular cyclic adenosine monophosphate (cAMP) changes was performed using the HTRF cAMP Dynamic Assay Kit from CisBio (Codolet, France). The assay is based on the competition between native cAMP produced by the cells and cAMP labeled with the dye d2, using a homogeneous time-resolved fluorescence method. Binding of the tracer is determined by an anti-cAMP antibody labeled with cryptoacid. The effect of the compound alone (agonism) was measured by performing the assay in the absence of dopamine, whereas the effect of the compound as a positive allosteric modulator (PAM) was measured using the EC 20 The measurements were performed in the presence of dopamine at a concentration of 0.1 mM. The test compound (usually 10 -9.5 M~10 -4.5 Cells (20,000 per well) were plated in a 384 well plate and incubated for 1 h at room temperature in a final volume of 20 μL HBSS (Lonza, calcium, magnesium, HEPES buffer 20 mM, pH 7.4) containing 10 mM β-glucose (10 mM). The reaction was then terminated and the cells lysed by adding d2 detection reagent (10 μL) in lysis buffer and cryptoacid reagent (10 μL) in lysis buffer according to the manufacturer's instructions. This was incubated for a further 60 min at room temperature and the change in HTRF fluorescence emission ratio was measured using a laser-excited Envision plate reader (Perkin Elmer, Zaventem, Belgium) according to the manufacturer's instructions. All incubations were performed in duplicate and the results were compared to a concentration-effect curve for dopamine (10 -11 M to 10 -6 M).

[0092] c. Data Analysis Data were analyzed using Excel and PRISM (GraphPad Software), and pEC 50Erel was calculated by subtracting the basal state from the maximum response of the test substance, and expressed as a relative percentage when the response obtained with dopamine was taken as 100%.

[0093] pEC of compound 50 is the -log10 of the concentration of compound that produces a 50% enhancement of cAMP levels.

[0094] Erel indicates relative efficacy and is defined as the % maximal enhancement produced by a compound compared to the maximal response produced by increasing concentrations of dopamine (Erel of 1 = maximal response of dopamine).

[0095] When tested in this assay, the compound of formula (Ia) had a pEC50 value of about 6.9 and the compound of formula (Ib) had a pEC50 value of about 6.7.

[0096] The corresponding Erel of the compound of formula (Ia) is about 64%, and the corresponding Erel of the compound of formula (Ib) is about 61%.

[0097] GABA A Automated patch clamp testing of receptor cells Human GABA A CHO-K1 cells stably expressing the receptor α1, β2, and β2 subunits were used. Cells were harvested with trypsin and maintained at room temperature in serum-free medium. Before the test, cells were washed and resuspended in extracellular fluid.

[0098] Patch clamp testing Human GABA A Experiments on α1β2γ2 channels were performed using an automated patch clamp assay (IonFlux™ HT). Compounds were tested in three concentrations (0.1, 1, and 10 μM) in triplicate cells. AThe external solution for recording currents consisted of 137 mM sodium chloride, 4 mM potassium chloride, 1.8 mM calcium chloride, 1 mM magnesium chloride, 10 mM HEPES, and 10 mM glucose. Both the external and internal solutions were titrated with NaOH or KOH to obtain a pH of 7.35 or 7.3, respectively. The internal pipette solution contained 70 mM potassium fluoride, 60 mM potassium chloride, 70 mM sodium chloride, 5 mM HEPES, 5 mM EGTA, and 4 mM magnesium ATP. The final concentration of the vehicle used to dilute the compounds was 0.33% DMSO in each well. Bicuculline (0.032–100 μM) was used as a positive control inhibitor. GABA (15 μM) was used as an agonist. All recordings were obtained from a holding potential of -60 mV.

[0099] The order of compound addition was as follows: EC 80 A single concentration of GABA was added. Each concentration of compound was applied for 30 seconds, followed by the addition of 15 μM GABA in the presence of compound for 2 seconds. This process was repeated with the next ascending concentration of compound. Peak inward currents in response to GABA addition in the presence of a single concentration of compound were measured. Data for all compounds were normalized to the baseline peak current evoked by the addition of 15 μM GABA for 2 seconds.

[0100] When tested in the above assay, at a concentration of 10 μM, the compound of formula (Ia) inhibited approximately 13% of the GABA A The percentage of receptor inhibition is shown.

[0101] When tested in the above assay, at a concentration of 10 μM, the compound of formula (Ib) inhibited approximately 20% of the GABA A The percentage of receptor inhibition is shown.

[0102] Evaluation of CYP3A4 inhibitory activity in vitro using cryopreserved human microsomes The purpose of the human microsomal assay is to determine the inhibitory potential of compounds of formula (I) by measuring CYP3A4 activity following exposure to midazolam, a specific CYP3A4 substrate.

[0103] For this purpose, cryopreserved human microsomes (pooled donors) are aliquoted into 48-well collagen-coated plates to a final concentration of 0.25 mg / ml. UCB compounds are then added to the wells in two batches at concentrations of 1 μM and 20 μM. After 30 min of incubation, midazolam is added at a concentration of 2.5 μM. After 15 min, an aliquot is removed and placed in the same volume of methanol containing an internal standard. The samples are centrifuged at 2500 rpm for 20 min at 4 °C. An aliquot of the supernatant is diluted with deionized water and the concentration of 1-hydroxymidazolam is quantified using a standard LC MS / MS method.

[0104] Concentrations are compared to those obtained after incubation of midazolam at the same concentrations, but without preincubation of UCB compounds. Results are expressed as % inhibition.

[0105] The compound of formula (Ia) according to the present invention exhibits an inhibition rate of CYP3A4 of about 28% at a concentration of 20 μM and about 20% at a concentration of 1 μM.

[0106] Azamulin Assay Cryopreserved human hepatocytes (pool of 20 donors, BSU batch from Celsis / IVT / Bioreclamation) were thawed according to the donor's information. Viability (by trypan blue exclusion) was >75%. Preincubation (2x10 cells) 6Hepatocyte suspension (250 μL, 100 hepatocytes / mL) was incubated in William's medium containing 2 mM glutamine and 15 mM Hepes in a 48-well plate at +37°C incubator (5% CO2) under gentle agitation (vibrating agitator Titramax 100, approximately 300 rpm) for 30 min. After preincubation, incubation was started by adding 250 μL of culture medium (see composition above) containing UCB compounds (1 μM) or midazolam (positive control) to the hepatocytes. The final concentration of UCB compounds in the culture medium was 0.5 μM. The cell suspension was quickly rehomogenized by pipetting in and out twice. After incubation for 0, 30, 60, 120, 180, and 240 min, the reaction was stopped by transferring 50 μl of the culture medium to the appropriate wells of a 96-well plate containing 50 μL of ice-cold acetonitrile containing 1 μM ketoconazole as an internal standard. Before each sampling, the cell incubation was rehomogenized by two in-out pipettings.

[0107] The samples were analyzed by LC-MS-MS bioanalytical method and the concentration of UCB compounds was determined. The concentration vs. time profiles were fitted to obtain the concentration-to-time ratio of μl / min / 10 6 The intrinsic clearance (Clint) expressed by the cells is determined.

[0108] When incubated with different concentrations of human hepatocyte suspensions, the intrinsic clearance (Clint) of the compound of formula (Ia) according to the invention is approximately 8.8 μl / min / 10 6 The intrinsic clearance (Clint) of the compound of formula (Ib) is approximately 9.2 μl / min / 10 6 It is a cell.

[0109] The following examples illustrate the preparation of compounds of formula (I) according to the invention. EXAMPLES

[0110] example Abbreviations / Recurring Reagents ACN: Acetonitrile cAMP: cyclic adenosine monophosphate Brine: Saturated aqueous sodium chloride solution nBu: n-butyl tBu: tert-butyl CHO: Chinese hamster ovary m-CPBA: 3-chloroperbenzoic acid CYP450: Cytochrome P450 DCM: dichloromethane DMF: N,N-dimethylformamide DMSO: Dimethyl sulfoxide EC 20 / 50 : Concentration that produces 20% / 50% of maximum response EGTA: Egtazic acid Erel: Relative Effectiveness ES + : Electrospray positive ionization Et: Ethyl EtOH: Ethanol Et2O: Diethyl ether EtOAc: ethyl acetate GABA: gamma-aminobutyric acid h: time HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid HPLC: High Pressure Liquid Chromatography HTRF: Homogeneous time-resolved fluorescence LCMS: Liquid Chromatography Mass Spectrometry LDA: Lithium diisopropylamide MeOH: Methanol min.:min NMR: nuclear magnetic resonance iPrOH: Isopropanol rt: room temperature SFC: Supercritical Fluid Chromatography TEA: Triethylamine THF: tetrahydrofuran TLC: Thin Layer Chromatography IUPAC names were determined using Biovia Draw 16.1.

[0111] Analysis method All reactions involving air- or moisture-sensitive reagents were performed under a nitrogen or argon atmosphere using dry solvents and glassware. Commercially available solvents and reagents were typically used without further purification, including anhydrous solvents where necessary (typically Sure-Seal™ products from Aldrich Chemical Company or AcroSeal™ from ACROS Organics). Reactions were typically followed by thin layer chromatography, HPLC, or mass spectrometry.

[0112] HPLC analysis was performed using an Agilent 1100 series HPLC system equipped with a Waters XBridge MS C18, 5pm, 150X4.6mm column. The gradient was from 100% solvent A (water / ACN / ammonium formate solution 85 / 5 / 10 (v / v / v)) to 100% solvent B (water / ACN / ammonium formate solution 5 / 85 / 10 (v / v / v)) in 6 min with a hold at 100% B for 5 min. The flow rate was 8 mL / min for 6 min, increased to 3 mL / min for 2 min, and held at 3 mL / min for 3 min. A 1 / 25 split was used just before the API source. Chromatography was performed at 45 °C. Ammonium formate solution (pH ~8.5) was prepared by dissolving ammonium formate (630 mg) in water (1 L) and adding ammonium hydroxide 30% (500 μL).

[0113] It will be apparent to one skilled in the art that different analytical conditions will result in different retention times in the LC data.

[0114] Mass spectrometry in LCMS mode is performed as follows.

[0115] - For basic elution, the analysis is carried out as follows: For LCMS analysis, a simple quadrupole mass spectrometer from QDA Waters is used. The mass spectrometer is equipped with an ESI source and a UPLC Acquity Hclass with a diode array detector (200-400 nm). Data are acquired with full MS scans from m / z 70 to 800 in positive mode with basic elution. Reversed phase separation is performed at 45 °C using a Waters Acquity UPLC BEHC18 1.7 μm (2.1x50 mm) column with basic elution. Gradient elution is performed with water / ACN / ammonium formate (95 / 5 / 63 mg / L) (solvent A) and ACN / water / ammonium formate (95 / 5 / 63 mg / L) (solvent B). Injection volume: 1 μL. Full flow rate on MS.

[0116] Basic Program "4min" [Table 1]

[0117] Basic program "10min" [Table 2]

[0118] - In the case of acidic elution, the analysis is carried out as follows: A simple quadrupole mass spectrometer from QDA Waters is used for LCMS analysis. The mass spectrometer is equipped with an ESI source and a UPLC Acquity Hclass with a diode array detector (200-400 nm). Data are acquired in positive mode with an acidic eluent and a full MS scan from m / z 70 to 800. Reversed phase separation is performed at 45 °C using a Waters Acquity UPLC HSS T3 1.8 μm (2.1x50 mm) column for acidic elution. Gradient elution is performed with water / ACN / TFA (95 / 5 / 0.5 mL / L) (solvent A) and ACN (solvent B). Injection volume: 1 μL. Full flow rate on MS.

[0119] Acid Program "4 minutes" [Table 3]

[0120] Acid program "10 minutes" [Table 4]

[0121] The crude material can be purified by normal phase chromatography, (acid or base) reverse phase chromatography, chiral separation, or recrystallization.

[0122] Conventional reverse phase chromatography is performed using a silica gel column (100:200 mesh silica gel or Interchim's Puriflash®-50SIHC-JP column).

[0123] Preparative reverse phase chromatography is performed as follows. LCMS purification (fundamental mode, LCMS prep) is used using an SQD or QM Waters triple quadrupole mass spectrometer equipped with an ESI source and a preparative LC controller Waters quadrupole pump with a diode array detector (210-400 nm).

[0124] MS parameters: ESI capillary voltage 3 kV. Cone and extractor voltage 10. Source block temperature 120° C. Desolvation temperature 300° C. Cone gaz flow rate 30 L / h (nitrogen), desolvation gas flow rate 650 L / h. Data are acquired with a full MS scan from m / z 100 to 700 in positive mode with acidic or basic elution.

[0125] LC parameters: Reversed phase separation is performed at rt using an XBridge prep OBD C18 column (5 μm, 30x50 mm) (basic elution). Gradient elution is performed with water (solvent A), ACN (solvent B), ammonium bicarbonate 8 g / L + 500 μL / L NH4OH 30% in water (solvent C) (pH ~ 8.5). HPLC flow rate 35 mL / min ~ 60 mL / min, injection volume: 1 mL. Split ratio was ± 1 / 6000 for MS.

[0126] [Table 5]

[0127] The crude material can be purified by normal phase chromatography, (acid or base) reverse phase chromatography, chiral separation, or recrystallization.

[0128] The products were typically dried under vacuum before submission for final analytical or biological testing.

[0129] All NMR spectra were obtained at 250 MHz, 300 MHz, 400 MHz or 500 MHz.

[0130] 1. Preparation of intermediate (II)-2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetic acid [ka]

[0131] 1.1 Preparation of 3,5-dichloro-4-methyl-pyridine a2 Charge LDA (1.86 L, 2 M solution in THF, 3.72 mol) and THF (5.0 L) to a reactor under nitrogen. Add 3,5-dichloro-4-methyl-pyridine a1 (500 g, 3.38 mol) at -20 °C and stir the mixture at -10 °C for 30 min. Cool the reaction to -70 °C and add methyl iodide (815 g, 5.74 mol). Allow the mixture to warm to room temperature and stir for 4 h. This overall procedure is carried out in parallel with four batches of equal size, which are worked together. Cool the mixture to 0 °C, quench with water (5 L) and stir for 10 min. Extract the aqueous phase with ethyl acetate (2 x 3 L) and wash the combined organic phase twice with brine (10 L), dry over anhydrous sodium sulfate, filter and concentrate under vacuum. The crude product is purified by recrystallization from ethanol (4 L) at -70°C to give 3,5-dichloro-4-methyl-pyridine a2 as a yellow solid (1.5 kg, 68.5% yield).

[0132] 1.2 Preparation of methyl 2-(3,5-dichloro-4-pyridyl)acetate - intermediate a3 Charge 3,5-dichloro-4-methyl-pyridine a2 (375 g, 2.31 mol) and DMF (1.87 L) into the reactor and cool the mixture to 15 °C. Add potassium tert-butoxide (779 g, 6.94 mol) under nitrogen at 10-15 °C and stir the mixture at 15 °C for 30 min. Add dimethyl carbonate (730 g, 8.10 mol) at 10-15 °C and stir the mixture at 30 °C for 4 h. This overall procedure is carried out in parallel for four batches of equal size, which are worked together. Cool the mixture to 0 °C and quench the reaction with water (10 L) and stir for 10 min. Filter the reaction mixture and wash the filter cake twice with ethyl acetate (2 L). The aqueous phase was extracted twice with ethyl acetate (3 L) and the combined organic phase was washed twice with brine (5 L), dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to give methyl 2-(3,5-dichloro-4-pyridyl)acetate a3 as a dark brown liquid (1.3 kg, 63.8% yield), which was used in the next step without further purification.

[0133] 1.3. Preparation of methyl 2-(3,5-dichloro-1-oxide-pyridin-1-ium-4-yl)acetate - intermediate a4 Methyl 2-(3,5-dichloro-4-pyridyl)acetate a3 (650 g, 2.95 mol) and dichloromethane (3.25 L) are placed in a reactor. m-CPBA (1.27 kg, 5.91 mol, 80% purity) is added under nitrogen at 0 °C and the mixture is stirred at 25 °C for 5 h. This overall procedure is carried out in parallel with two batches of the same size working together. The mixture is cooled to 0 °C and the reaction is quenched with water (4 L) and stirred for 10 min. The reaction mixture is filtered and the filter cake is washed twice with dichloromethane (3 L). The aqueous phase is extracted twice with dichloromethane (2 L) and the combined organic phase is washed three times with a saturated solution of Na2S2O3 (15 L) and twice with brine (10 L), before being dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by silica gel chromatography (petroleum ether:ethyl acetate 20:1 to 1:1) to obtain methyl 2-(3,5-dichloro-1-oxide-pyridin-1-ium-4-yl)acetate a4 as a yellow solid (900 g, 64.2% yield).

[0134] 1.4. Preparation of methyl 2-(2-bromo-3,5-dichloro-4-pyridyl)acetate - intermediate a5 Methyl 2-(3,5-dichloro-1-oxido-pyridin-1-ium-4-yl)acetate a4 (900 g, 3.81 mol) and acetonitrile (8 L) are charged to a reactor at 20 °C. Phosphorus oxybromide (POBr3, 1.09 kg, 3.81 mol) is added under nitrogen at 0 °C and the mixture is stirred at 25 °C for 12 h. This general procedure is carried out in parallel with another batch (1.64 mol scale) and the two are worked up together. The mixture is cooled to 0 °C and the reaction is quenched with water (3 L) and stirred for 10 min. The aqueous phase is extracted twice with ethyl acetate (2 L). The combined organic phase is washed twice with brine (5 L), dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by silica gel chromatography (petroleum ether:ethyl acetate 50:1 to 1:1) to give methyl 2-(2-bromo-3,5-dichloro-4-pyridyl)acetate a5 as an off-white solid (503 g, 43% yield).

[0135] 1 HNMR(400MHz,CDCl3)δ8.32(s,1H),4.07(s,2H),3.75(s,3H)

[0136] 1.5. Preparation of methyl 3,5-dichloro-4-(2-methoxy-2-oxoethyl)pyridine-2-carboxylate - intermediate a6 To a solution of methyl 2-(2-bromo-3,5-dichloro-4-pyridyl)acetate a5 (3 g, 10.03 mmol) in methanol (60 mL) was added N,N-diisopropylethylamine (2.42 mL, 14.6 mmol) and 1,4-bis(diphenylphosphino)butanepalladium(II) chloride (91 mg, 0.15 mmol). The reactor was flushed three times with nitrogen and then pressurized with 5 bar carbon monoxide (flush three times) and the mixture was heated at 80° C. for 3 h. The reaction mixture was filtered over Celite at room temperature and the solvent was removed under reduced pressure. The crude product was purified by column chromatography (Biotage SNAP Ultra 25 g, eluent: ethyl acetate:hexane 1:1). The solvent was removed under vacuum to give 3,5-dichloro-4-(2-methoxy-2-oxoethyl)pyridine-2-carboxylate a6 as a yellow liquid (1.84 g, 66% yield).

[0137] LCMS(MH + ):278 1 H NMR (400MHz, DMSO-d6) δ8.75(s,1H),4.12(s,2H),3.93(s,3H),3.68(s,3H).

[0138] 1.6. Preparation of methyl 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetate - intermediate a7 To a solution of methyl 3,5-dichloro-4-(2-methoxy-2-oxoethyl)pyridine-2-carboxylate a6 (305 mg, 1.09 mmol) in THF (10 mL) was added sodium borohydride (124 mg, 3.29 mmol) at room temperature and the reaction mixture was allowed to stir at room temperature for 18 h. The reaction mixture was filtered and the solvent removed under vacuum. The crude product was purified by column chromatography (Biotage SNAP Ultra 25 g, eluent: dichloromethane:methanol 100:0 to 90:10). The solvent was removed under vacuum to give methyl 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetate a7 as a solid (139 mg, 50% yield).

[0139] LCMS(MH + ):250 1 H NMR (400 MHz, CDCl3) δ 8.51 (s, 1H), 4.78 (s, 2H), 4.04 (s, 2H), 3.74 (s, 3H). No OH protons were observed.

[0140] 1.7. Preparation of intermediate (II)-2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetic acid. To a solution of methyl 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetate a7 (98.1 g, 392 mmol) in a mixture of THF (1.1 L) and water (110 mL) was added lithium hydroxide monohydrate (25.2 g, 589 mmol). The resulting mixture was stirred at room temperature for 18 h and then concentrated in vacuo. The residue was azeotroped with toluene (3×250 mL) to give 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetic acid (II) as a free-flowing off-white powder (92.6 g, 100% yield). This product was used in the next step without further purification.

[0141] 1 H NMR (400 MHz, DMSO-d6) δ 8.54 (s, 1H), 4.62 (s, 2H), 2.46 (s, 2H). Two OH protons were not observed.

[0142] 2. Preparation of intermediate (III) Preparation of (1R)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(R,S) and (1S)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(S,S) [ka]

[0143] 2.1. Preparation of intermediate (VI) - 7-bromo-10b-methyl-6,10b-dihydro-5H-[1,3]oxazolo[2,3-a]isoquinoline-2,3-dione a9 To a solution of N-[2-(2-bromophenyl)ethyl]acetamide a8 (commercially available, 106.5 g, 439.8 mmol) in DCM (1.5 L) was added oxalyl chloride (72 mL, 838.7 mmol) dropwise at 0 °C. The mixture was stirred at 0 °C for 2 h, then warmed to rt and stirred for 3 h. The reaction mixture was then cooled to 0 °C and ferric chloride (86 g, 530.2 mmol) was added in two portions. The reaction mixture was warmed to rt and stirred at rt overnight, diluted with DCM (2.5 L) and quenched with 12 M concentrated ammonia solution (200 mL) at 0 °C. The organic layer was dried over Na2SO4, filtered and concentrated under vacuum to give 108 g of 7-bromo-10b-methyl-6,10b-dihydro-5H-[1,3]oxazolo[2,3-a]isoquinoline-2,3-dione a9 as a brown solid, which was used in the next step without further purification.

[0144] Yield (crude): 83%. LCMS(ES + ):296 / 298(M+H + ).

[0145] 2.2. Preparation of intermediate (V)-5-bromo-1-methyl-3,4-dihydroisoquinoline a10 To a suspension of 7-bromo-10b-methyl-6,10b-dihydro-5H-[1,3]oxazolo[2,3-a]isoquinoline-2,3-dione a9 (108 g, 364.72 mmol) in MeOH (1.5 L) was added sulfuric acid (75 mL) dropwise at rt. The reaction mixture was stirred at 65 °C overnight and then quenched with 15 M concentrated ammonia solution (300 mL) at 0 °C. The mixture was concentrated under vacuum and water (300 mL) was added. The aqueous layer was extracted six times with DCM (1 L). The organic layer was dried over MgSO4, filtered and concentrated under vacuum to give 86.44 g of 5-bromo-1-methyl-3,4-dihydroisoquinoline a10 as a brown solid, which was used in the next step without further purification.

[0146] Yield (crude): quantitative HPLC (basic mode): RT 4.75 min, purity 87%.

[0147] 2.3. Preparation of intermediate (IV)-5-bromo-1-methyl-1,2,3,4-tetrahydroisoquinoline a11 To a solution of 5-bromo-1-methyl-3,4-dihydroisoquinoline a10 (86.44 g, 385.9 mmol) in EtOH (2 L) was added sodium borohydride (13.2 g, 349 mmol) in portions at 0 °C (13 * 1g). The mixture was stirred at 0°C for 2 h, then 5N aqueous HCl (250 mL) was added at 0°C. The reaction mixture was stirred at rt overnight, then EtOH was concentrated under vacuum. DCM (1 L) was added and the mixture was quenched with 6M concentrated ammonia solution (400 mL) at 0°C. The organic layer was extracted twice with DCM (500 mL), dried over MgSO4, filtered and concentrated under vacuum to give 83 g of 5-bromo-1-methyl-1,2,3,4-tetrahydroisoquinoline a11 as a brown solid, which was used in the next step without further purification.

[0148] Yield (crude): 95%. HPLC (basic mode): RT 4.53 min, purity 80%.

[0149] 2.4. tert-Butyl 5-bromo-1-methyl-3,4-dihydroisoquinoline-2(1H)-carboxylate - Preparation of intermediates a12, a12-S and a12-R To a solution of 5-bromo-1-methyl-1,2,3,4-tetrahydroisoquinoline a11 (78 g, 345 mmol) in DCM (1 L) was added TEA (160 mL, 1136 mmol) at 0 °C. Then, a solution of di-tert-butyl dicarbonate (65 g, 294.8 mmol) in DCM (250 mL) was added dropwise at 0 °C. The reaction mixture was stirred at rt overnight and quenched with water (100 mL). The organic layer was dried over MgSO4, filtered and concentrated under vacuum. The residue was triturated twice with a mixture of MeOH / n-hexane (1:2, 450 mL) to give 63 g of tert-butyl 5-bromo-1-methyl-3,4-dihydroisoquinoline-2(1H)-carboxylate a12 (yield: 56%, HPLC (basic mode): RT 6.59 min, purity 98%) as a white solid. Chiral separation of racemic tert-butyl 5-bromo-1-methyl-3,4-dihydroisoquinoline-2(1H)-carboxylate a12 (SFC, Whelko 01(R,R), 50 * 227 mm, 360 mL / min, 220 nm, 25°C, eluent: 20% iPrOH) -25.1 g of tert-butyl (1S)-5-bromo-1-methyl-3,4-dihydroisoquinoline-2(1H)-carboxylate a12-S was obtained as a solid.

[0150] Yield: 22%. HPLC (basic mode): RT 6.59 min, purity 91%. Chiral analysis (LC, Whelko-01(R,R), 250 * 4.6 mm, 1 mL / min, 220 nm, 30°C, eluent: iPrOH / n-heptane / DEA 50 / 50 / 0.1) RT 4.86 min, 97.7% ee. - 29.3 g of tert-butyl (1R)-5-bromo-1-methyl-3,4-dihydroisoquinoline-2(1H)-carboxylate a12-R as a solid.

[0151] Yield: 26%. HPLC (basic mode): RT 6.59 min, purity 98%. Chiral analysis (LC, Whelko-01(R,R), 250 * 4.6 mm, 1 mL / min, 220 nm, 30°C, eluent: iPrOH / n-heptane / DEA 50 / 50 / 0.1) RT 5.62 min, 92.4% ee.

[0152] 2.5. Preparation of tert-butyl (1S)-5-[(1R)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate intermediate a13-(S,R) and tert-butyl (1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate intermediate a13-(S,S) tert-Butyl (1S)-5-bromo-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate a12-S (7 g, 21.45 mmol) was dissolved in dry tetrahydrofuran (107 mL) at -78 °C, n-BuLi (32.93 mmol) was added dropwise and the mixture was stirred at -78 °C for 10 min. Fluoroacetone (4.78 mL, 64.2 mmol) was added and the mixture was stirred at rt for 1 h. The reaction mixture was quenched with 1N aqueous hydrochloric acid (350 mL) and then extracted three times with dichloromethane. The organic layer was dried over MgSO4, filtered and concentrated under vacuum. The residue was purified by reversed phase chromatography (basic mode, standard LC). Chiral separation (LC, chiralpak IC, 80 * 380 mm, 300 mL / min, 220 nm, 30°C, eluent: 10% iPrOH in heptane. There was obtained 1.137 g of tert-butyl (1S)-5-[(1R)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate a13-(S,R) as a beige solid.

[0153] Yield: 16 LCMS(ES + ):268.0(M-tBu+H + ). Chiral analysis (LC, Whelko-01(R,R), 150 * 4.6 mm, 1.5 mL / min, 220 nm, 30°C, eluent: iPrOH / n-heptane / DEA 10 / 90 / 0.1): RT 2.37 min, 100% ee. - 1.074 g of tert-butyl (1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate a13-(S,S) as a beige solid

[0154] Yield: 15% LCMS(ES + ):268.0(M-tBu+H) + . Chiral analysis (LC, Whelko-01(R,R), 150 * 4.6 mm, 1.5 mL / min, 220 nm, 30°C, eluent: iPrOH / n-heptane / DEA 10 / 90 / 0.1). RT 2.72 min, 100% ee.

[0155] 2.6. Preparation of (1R)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(R,S) and (1S)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride - intermediate a14-(S,S) tert-Butyl (1S)-5-[(1R)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate a13-(S,R) (1.137 g, 3.516 mmol) was dissolved in dioxane (18 mL) at rt. A 4N solution of HCl in dioxane (8.8 mL, 35 mmol) was added. The mixture was stirred at rt overnight. The reaction mixture was concentrated under vacuum to give 950 mg of (1R)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(R,S) as a beige solid.

[0156] Yield (crude): quantitative LCMS(ES + ):224.0(M+H) + . (1S)-1-Fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(S,S) Compound a14-(S,S) can be synthesized following a similar method starting from tert-butyl (1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinoline-2-carboxylate a13-(S,S).

[0157] Yield (crude): quantitative LCMS(ES + ):224(M+H) + .

[0158] 3. Preparation of Compounds of Formula (I) 3.1. Preparation of compound of formula (Ia) - 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[(1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl]ethanone [ka]

[0159] To a solution of 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]acetic acid A (112 mg, 0.476 mmol) and (2S)-1-fluoro-2-[(1S)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(S,S) (136 mg, 0.524 mmol) in DMF (6 mL) was added (2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU, 217 mg, 0.571 mmol). N,N-diisopropylethylamine (0.24 mL, 1.43 mmol) was added at room temperature and the mixture was stirred for 2 h. The reaction mixture was quenched with water and extracted twice with ethyl acetate. The combined organic layers were dried over MgSO4, filtered and the solvent removed under vacuum to give the crude product. The crude product was purified by reverse phase chromatography (basic mode) and the solvent removed under vacuum to give 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[(1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl]ethanone 1 (116 mg, 55% yield) as a solid.

[0160] LCMS. 441(MH + ) 1 H NMR (400MHz, DMSO-d6) δ8.59 (2s, 1H, rotamer), 7.37-7.09 (m, 3H), 5.48 (m, 1H), 5.34 (m, 2H), 4.72-4.53 ( m,3H),4.53-4.25(m,1.3H),4.25-4.03(m,1.7H),4.02-3.69(m,2H),3.48(m,0.7H),3.38-3.33(m,0.3H) (partially under water signal), 3.31-3.07 (m, 1H), 1.60 (d, J = 6.7 Hz, 1 H), 1.53 (m, 3 H), 1.37 (d, J = 6.7 Hz, 2 H).

[0161] 3.2. Preparation of the compound of formula (Ib) 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[(1S)-5-[(1R)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl]ethanone The title compound was prepared from (2S)-1-fluoro-2-[(1R)-1-methyl-1,2,3,4-tetrahydroisoquinolin-5-yl]propan-2-ol hydrochloride a14-(S,R) by a procedure similar to that described for compound of formula (Ia).

[0162] LCMS: 441(MH + ) 1 H NMR (400 MHz, DMSO-d6) δ 8.58 (2s, 1H, two rotamers), 7.42-7.07 (m, 4H), 5.47 (s, 1H, rotamer), 5.41-5.24 (m, 2H), 4.85-4.66 (m, 1H), 4.57-4.24 (m, 2H), 4.09 (s, 3H), 4.01-3.70 (m, 2H), 3.58-3.19 (m, 1H partially below water signals), 1.59 (d, J = 6.7 Hz, 1H), 1.53 (m, 3H), 1.36 (dd, J = 6.8, 2.0 Hz, 2H).

Claims

1. A compound of formula (I), or a pharma- ceutically acceptable salt thereof. 【Chemistry 1】

2. The compound of formula (I) according to claim 1, which is 2-[3,5-dichloro-2-(hydroxymethyl)-4-pyridyl]-1-[(1S)-5-[(1S)-2-fluoro-1-hydroxy-1-methyl-ethyl]-1-methyl-3,4-dihydro-1H-isoquinolin-2-yl]ethanone and is represented by formula (IA). 【Chemistry 2】

3. A pharmaceutical composition comprising a compound of formula (I) as defined in claim 1 or a pharma- ceutically acceptable salt thereof, together with a pharma- ceutically acceptable carrier.

4. 10. A compound of formula (I) as defined in claim 1, or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition as defined in claim 3, for use in therapy.

5. A compound of formula (I) as defined in claim 1, or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition as defined in claim 3, for use in the treatment and / or prevention of diseases and / or disorders in which the D1 receptor is involved.

6. 10. The compound of formula (I) as claimed in claim 1, or a pharma- ceutically acceptable salt thereof, or the pharmaceutical composition as claimed in claim 3, for use in the treatment and / or prophylaxis of cognitive and negative symptoms in schizophrenia, cognitive impairment associated with neuroleptic therapy, mild cognitive impairment (MCI), impulsivity, attention deficit hyperactivity disorder (ADHD), Parkinson's disease and other movement disorders, dystonia, Parkinson's dementia, Huntington's disease, dementia with Lewy bodies, drug dependence in Alzheimer's disease, sleep disorders, apathy, traumatic spinal cord injury, or neuropathic pain.

7. 4. A compound of formula (I) as claimed in claim 1, or a pharma- ceutically acceptable salt thereof, or a pharmaceutical composition as claimed in claim 3, for use in the treatment of cognitive and negative symptoms in Parkinson's disease and other movement disorders, Alzheimer's disease, or schizophrenia.

Images