difluoromethyl-pyridin-2-yl triazole

Abstract

The present invention relates to difluoromethyl-pyridin-2-yl triazoles of general formula (I) which are modulators of GABA A receptors containing the α5 subunit, useful in the treatment of central nervous system disorders and other disorders. Furthermore, the present invention relates to processes for preparing pharmaceutical compositions and processes for manufacturing the compounds according to the invention.

Description

TECHNICAL FIELD

[0001] The present invention relates to difluoromethyl-pyridin-2-yl-triazoles of general formula (I) which are modulators of GABA A receptors containing the a5 subunit. The compounds are useful for the treatment of central nervous system and other diseases. In addition, the present invention relates to a process for the preparation of a pharmaceutical composition as well as to a process for the manufacture of the compounds according to the present invention. BACKGROUND

[0002] GABA A receptors containing the a5 subunit represent a therapeutic target for the treatment of various diseases and disorders of the central nervous system. GABA A receptors containing the a5 subunit have been established as a therapeutic target. It is particularly desirable to be able to modulate GABA A receptors containing the a5 subunit are useful candidates especially for the treatment of cognitive disorders, Alzheimer’s disease, schizophrenia, positive, negative and / or cognitive symptoms related to schizophrenia, cognitive impairment related to schizophrenia, and cognitive deficits related to Down’s syndrome, autism, neurofibromatosis type I, or after stroke.

[0003] WO 2012 / 062687 A1 (corresponding to EP-2638029-A1) discloses triazole derivatives for the treatment of neurological disorders.

[0004] WO 2020 / 016443 A1 discloses difluoromethyl- phenyl triazoles as GABA receptor modulators for the treatment of neurological diseases. The compounds contain a difluoromethyl group attached to a phenyl group which is attached to the triazole ring.

[0005] The present invention describes difluoromethyl- pyridine -2-yl-triazoles. The compounds contain a difluoromethyl group attached to a 2-pyridine group which is attached to the triazole ring. The combination of the 2-pyridyl group with the attached difluoromethyl group surprisingly results in the compounds being significantly more potent modulators of GABA A receptors containing the a5 subunit compared to the analogous compounds described in WO 2020 / 016443. The potency of the compounds can be measured in the assay A described below in terms of the Ki value of the compounds. In the case of the present invention, the combination of the pyridyl group (instead of the phenyl group used in the phenyl triazoles of WO 2020 / 016443) with the difluoromethyl group in the 4-position unexpectedly increases the potency of the claimed compounds by a factor of at least about 10 or more overall.

[0006] The potency of the compounds is compared to GABA A5R binding constant Ki is related, where increased potency translates into lower effective doses of the respective compound for disease treatment.

[0007] objects of the invention

[0008] Surprisingly, it has been found that pyridin-2-yl-triazoles of general formula (I),

[0009]

[0010] wherein:

[0011] • Xaand Xbare not identical to each other and represent C or N, and

[0012] • R1is a substituted phenyl or a 5- or 6-membered heterocyclyl ring containing 1 or 2 or 3 heteroatoms

[0013] are GABA A 5R negative modulators (i.e. GABA A 5R negative modulators of the a5subunit) with improved properties related to GABA A 5R binding properties, which means lower compound doses for disease treatment and minimization of side effects. Furthermore, the compounds of the present application have superior CNS penetration, with low efflux ratios from the brain compartment, which is necessary for drugs with intended action in the CNS, and high metabolic stability.

[0014] Accordingly, one aspect of the present application relates to compounds according to formula (I) or salts thereof, which are GABA A 5R negative modulators.

[0015] Another aspect of the present application relates to compounds according to formula (I) or pharmaceutically acceptable salts thereof, which are GABA A 5R negative modulators with high GABA A 5R binding properties.

[0016] Yet another aspect of the present application relates to compounds according to formula (I) or pharmaceutically acceptable salts thereof, which are GABA A 5R negative modulators with high GABA A 5R binding properties and superior CNS penetration, with low efflux ratios from the brain compartment and high metabolic stability.

[0017] In yet another aspect, the present application relates to pharmaceutical compositions containing at least one compound according to formula (I) or a pharmaceutically acceptable salt thereof, optionally together with one or more inert carriers and / or diluents.

[0018] Another aspect of the application relates to a process for the manufacture of the compounds of the application.

[0019] In particular, the present application relates to a compound according to Formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutical composition comprising a compound according to Formula (I) or a pharmaceutically acceptable salt thereof for use in the prevention and / or treatment of a disease or disorder which can be influenced by the negative modulation of GABA A 5R, such as acute neurological disorders, chronic neurological disorders, cognitive disorders, Alzheimer's disease, memory deficits, schizophrenia, positive, negative and / or cognitive symptoms associated with schizophrenia, cognitive impairment associated with schizophrenia, bipolar disorder, autism, Down syndrome, neurofibromatosis type I, post-operative cognitive decline, sleep disorders, circadian rhythm disorders, amyotrophic lateral sclerosis, dementia d u e to AIDS, psychotic disorders, substance-induced psychotic disorder, anxiety disorders, generalized anxiety disorder, panic disorder, delusional disorder, obsessive / compulsive disorders, acute stress disorder, drug addiction, movement disorders, Parkinson's disease, restless leg syndrome, cognitive deficit disorder, multi-infarct dementia, mood disorders, depression, major depressive disorder, neuropsychiatric conditions, psychosis, attention deficit hyperactivity disorder, neuropathic pain, stroke, attentional disorders, eating disorders, anorexia, anorexia nervosa, cachexia, weight loss, muscle atrophy, pain conditions, chronic pain, nociceptive pain, post-operative pain, osteoarthritis pain, rheumatoid arthritis pain, musculoskeletal pain, burn pain, ocular pain, pain due to inflammation, pain due to bone fracture, hyperalgesia, neuropathic pain, herpes-related pain, HIV-related neuropathic pain, traumatic nerve injury, recovery after traumatic brain injury, post-stroke pain, post-ischemic pain, fibromyalgia, chronic headache, migraine, tension-type headache, diabetic neuropathic pain, phantom-limb pain, visceral pain and cutaneous pain.

[0020] Other results or conclusions of the present application will become directly apparent to the skilled person from the foregoing and following comments. DETAILED DESCRIPTION

[0021] The present application relates to compounds of general formula (I),

[0022]

[0023] or salts thereof, wherein

[0024] Xaand Xbare not identical to each other and represent C or N, and R1is a substituted phenyl or a 5- or 6-membered substituted heterocyclyl ring containing 1 or 2 or 3 heteroatoms.

[0025] In particular, Xaor Xbis C.

[0026] R1is preferably selected from

[0027] • phenyl substituted by carbamoyl;

[0028] • 2-pyridinone unsubstituted or substituted by halogen such as fluorine or by methyl or ethyl on nitrogen;

[0029] • 2, 3 or 4-pyridinyl substituted by cyano- (NC-) or methylsulfide-, amino-, methyl-amino-, methylsulfonyl- or halogen;

[0030] • pyrimidinyl- unsubstituted or substituted by C 1-6 -alkyl-, amino-, -hydroxymethyl-; or pyrazinyl- or pyridazinyl;

[0031] • pyrrolyl- substituted by C 1-6 -alkyl- or NC-CH2-CH2- and thienyl- substituted by C 1-6 -alkyl-, C 3-5 -cycloalkyl-, NC-CH2-CH2-, amino-, methyl-amino- or halogen;

[0032] • imidazolyl- substituted by C 1-6 -alkyl-, carbamoyl-, NC-CH2-CH2-, amino- or -methylamino-;

[0033] • triazolyl- unsubstituted or substituted by C 1-3 -alkyl- such as methyl;

[0034] • oxazolyl- substituted by methyl and thienyl- substituted by NC-CH2-CH2-.

[0035] Unless otherwise indicated, groups, residues and substituents, in particular R1, are as defined above and below. If a residue, substituent or group occurs several times in a compound, they can have the same or different meanings. Some preferred meanings of groups and substituents of the compounds according to the application will be given below.

[0036] In yet another embodiment of the present application, R1is selected from

[0037] • phenyl substituted by carbamoyl, such as

[0038]

[0039] and

[0040] • 2-pyridinone unsubstituted or substituted by halogen such as fluorine or by methyl or ethyl on nitrogen, such as

[0041] • 2-pyridinone unsubstituted or substituted by halogen such as fluorine or by methyl or ethyl on nitrogen, such as

[0042] In yet another embodiment of the present application, R1is

[0043] • 2, 3 or 4-pyridyl substituted by NC- or -methylsulfide-, amino-, methyl-amino- or -methylsulfonyl or halogen, such as

[0044]

[0045]

[0046] In yet another embodiment of the present application, R1is selected from

[0047] In yet another embodiment of the present application, wherein R1is

[0048] • unsubstituted pyrimidinyl- or pyrimidinyl- substituted by C 1-6 -alkyl-, amino-, -hydroxymethyl-; or pyrazinyl- or pyridazinyl, such as

[0049]

[0050] In yet another embodiment of the present application, R1is

[0051] • pyrrolyl- substituted by C 1-6 -alkyl- or NC-CH2-CH2- and pyrazolyl- substituted by C 1-6 -alkyl-, C 3-5 -cycloalkyl-, NC-CH2-CH2-, -amino, -methyl-amino or -halogen, such as

[0052]

[0053]

[0054] In yet another embodiment of the present application, R1is

[0055] • imidazolyl- substituted by C 1-6 -alkyl-, carbamoyl, NC-CH2-CH2-, amino- or -methylamino-, such as

[0056]

[0057]

[0058] In yet another embodiment of the present application, R1is

[0059] • unsubstituted triazolyl- or triazolyl- substituted by C 1-3 -alkyl-, such as

[0060] In yet another embodiment of the invention, R1 is

[0061] • Oxazolyl groups substituted with methyl groups or thiophene groups substituted with NC-CH2-CH2-, such as

[0062]

[0063] Further preferred are the following compounds listed in Table 1:

[0064] Table 1 Compounds (C#) 1 to 56

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] Some of the terms used hereinbefore and hereinafter to describe the compounds according to the application will now be defined more closely.

[0085] Terms not specifically defined herein should be given the meaning commonly understood by those of skill in the art in view of the present disclosure and the context. However, as used herein, the following terms have the indicated meanings and adhere to the following conventions, unless expressly stated otherwise.

[0086] In the following defined groups (groups, radicals) or moieties, the number of carbon atoms is usually specified before the group, e.g., C 1-6 - alkyl means an alkyl group (group) or radical (radical) having 1 to 6 carbon atoms. Usually, in groups like HO-, H2N-, (O)S-, (O)2S-, NC- (cyano), HOOC-, F3C-, etc., the skilled person can see from the free valency of the group itself where the point of attachment to one or more groups of the molecule is. For combined groups comprising two or more subgroups, the last named subgroup is the point of group attachment, e.g., the substituent “aryl-C 1-3 - alkyl-” means a C 1-3 - alkyl bound aryl, the C 1-3 - alkyl is bound to the core or to the group to which the substituent is attached.

[0087] Generally, the point of attachment of a given residue to another group should be variable, i.e. any atom in this residue that has the ability to replace a hydrogen can be the point of connection to the attached group, unless otherwise specified.

[0088] In case of any inconsistency between the chemical name and the structural formula of a compound according to the application, the structural formula shall prevail.

[0089] Unless explicitly indicated, throughout the specification and the appended claims, a given chemical formula or name shall encompass all tautomers and all stereoisomers, optical isomers, and geometric isomers (e.g., enantiomers, diastereomers, E / Z isomers, etc.) thereof, as well as mixtures of any of the foregoing in all proportions, where such isomers and enantiomers exist, and salts, including pharmaceutically acceptable salts thereof, and solvates thereof, e.g., like hydrates, including solvates of the free compounds or of the salts of the compounds, unless explicitly indicated otherwise.

[0090] The phrase "pharmaceutically acceptable" or "physiologically acceptable" is employed herein to refer to those compounds, materials, compositions, and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication commensurate with a reasonable benefit / risk ratio.

[0091] As used herein, "pharmaceutically acceptable salts" refers to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali salts of acidic residues such as carboxylic acids; and the like. For example, such salts include salts of benzenesulfonic, benzoic, citric, ethanesulfonic, fumaric, gentisic, hydrobromic, hydrochloric, maleic, malic, malonic, mandelic, methanesulfonic, 4-methyl- benzenesulfonic, phosphoric, salicylic, succinic, sulfuric, and tartaric acids.

[0092] Other pharmaceutically acceptable salts can be formed from cations of ammonia, L-arginine, calcium, 2,2'-iminobisethanol, L-lysine, magnesium, N-methyl-D-glucamine, potassium, sodium, and tris(hydroxymethyl)-aminomethane.

[0093] The pharmaceutically acceptable salts of the present application can be synthesized from the parent compound that contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a sufficient amount of the appropriate base or acid in water or in an organic diluent like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile, or a mixture thereof. Salts of acids other than those mentioned above, which for example can be useful for purification or isolation of the compounds of the present application, such as trifluoroacetate salts, are also part of the present application.

[0094] The term "substituted" as used herein means that any one or more hydrogens of the designated atom is replaced with a selection from the indicated group, provided that the designated atom's valency is not exceeded, and that the substitution results in a stable compound.

[0095] The term "partially unsaturated" as used herein means that there are one, two or more, preferably one or two, double bonds in the designated group or moiety. Preferably, as used herein, the term "partially unsaturated" does not include groups or moieties that are completely unsaturated.

[0096] The term "halogen" generally represents fluorine (F), chlorine (CI), bromine (Br), and iodine (I).

[0097] The term "C 1-n- alkyl" (wherein n is an integer from 2 to n) denotes an acyclic, saturated, branched or straight-chain hydrocarbon radical having 1 to n C atoms. For example, the term C 1-5 - alkyl includes the groups H3C-, H3C-CH2-, H3C-CH2-CH2-, H3C-CH(CH3)-, H3C-CH2-CH2-CH2-, H3C-CH2-CH(CH3)-, H3C-CH(CH3)-CH2-, H3C-C(CH3)2-, H3C-CH2-CH2-CH2-CH2-, H3C-CH2-CH2-CH(CH3)-, H3C-CH2-CH(CH3)-CH2-, H3C-CH(CH3)-CH2-CH2-, H3C-CH2-C(CH3)2-, H3C-C(CH3)2-CH2-, H3C-CH(CH3)-CH(CH3)- and H3C-CH2-CH(CH2CH3)-.

[0098] The term "C 3-n - cycloalkyl" (wherein n is an integer from 4 to n) denotes a cyclic, saturated, unbranched hydrocarbon radical having 3 to n C atoms. For example, the term C 3-7 - cycloalkyl includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.

[0099] Many of the terms given above can be used repeatedly in the definition of a formula or a group and have one of the meanings given above independently of each other in each case.

[0100] The compounds according to the application can be obtained using synthesis methods which are known in principle. Preferably, the compounds are obtained by a process according to the application, which will be described in more detail below.

[0101] A general chemical synthetic route for the compounds disclosed herein is

[0102] Scheme 1:

[0103]

[0104]

[0105] Scheme 2:

[0106]

[0107]

[0108] Abbreviations:

[0109]

[0110]

[0111] Analytical HPLC method

[0112] Method A

[0113]

[0114] Analytical column: Sunfire C18 (Waters) 2.5 μm; 3.0 x 30 mm; column temperature: 60 °C

[0115] Method B

[0116]

[0117] Analytical column: Xbridge BEH C18, 2.1 x 30 mm, 1.7 μm; column temperature: 60 °C

[0118] Method C

[0119]

[0120] Analytical column: Sunfire (Waters) 2.5 μm; 3.0 x 30 mm; column temperature: 60 °C

[0121] Method D

[0122]

[0123] Analytical column: XBridge C18 (Waters) 2.5 μm; 3.0 x 30 mm; column temperature: 60 °C

[0124] Method E

[0125]

[0126] Analytical column: Sunfire C18 (Waters) 2.5 μm; 3.0 x 30 mm; column temperature: 60 °C

[0127] Method F

[0128]

[0129] Analytical column: Sunfire C18 (Waters) 2.5 μm; 3.0 x 30 mm; column temperature: 60 °C

[0130] Method G

[0131]

[0132] Analytical column: XBridge C18 (Waters) 2.5 pm; 3.0 x 30 mm; column temperature: 60 °C

[0133] Method H

[0134]

[0135] Analytical column: XBridge C18 (Waters) 2.5 pm; 3.0 x 30 mm; column temperature: 60 °C Method I

[0136]

[0137] Analytical column: XBridge BEH C18_2.1 x 30 mm_1.7 pm; column temperature: 60 °C

[0138] Method J

[0139]

[0140] Analytical column: Sunfire C18 (Waters) 2.5 pm; 3.0 x 30 mm; column temperature: 60 °C

[0141] Method K

[0142]

[0143] Analytical column: Sunfire C18 (Waters) 2.5 pm; 3.0 x 30 mm; column temperature: 60 °C

[0144] Method L

[0145]

[0146] Analytical column: Hypercarb_3.0 x 30 mm_3 pm; column temperature: 60 °C

[0147] Method M

[0148]

[0149] Analytical column: Acquity UPLC 1.8 pm C18 (2.1 x 50 mm), Column temperature: 25 °C

[0150] Method N

[0151]

[0152] Analytical column: Kinetex XB-C18 2.6 pm (4.6 x 50 mm), Column temperature: 25 °CPreparation of starting compounds I to XVIII

[0153] Example I : [3-(5-Difluoromethyl-pyridin-2-yl)-5-methyl-3H-[l,2,3]triazol-4-yl]-methanol

[0154]

[0155] 2-Azido-5-difluoromethyl-pyridine (25.7 g, 151 mmol) in 50 mL butan-2-ol was stirred at 120 °C for 5 days. The excess of alcohol was evaporated in vacuo as much as possible. 9.00 g of [3-(5-difluoromethyl-pyridin-2-yl)-5-methyl-3H-[l,2,3]triazol-4-yl]-methanol as a white solid was obtained by column chromatography on silica gel using DCM / acetone (10:1) as eluent.

[0156] 1 H NMR (400 MHz, DMSO-d6) δ ppm 2.32-2.43 (m, 3 H) 4.86 (s, 2 H) 7.26 (t, J=56.0 Hz 1 H) 8.11 (d, J=8.59 Hz, 1 H) 8.31 (s, 1 H) 8.84 (d, J=0.76 Hz, 1 H).

[0157] Example II : 2-Bromo-5-(difluoromethyl)pyridine

[0158]

[0159] To a solution of 6-bromo-pyridine-3-carbaldehyde (186 g, 1.00 mol) in 1.86 L dichloromethane at 0 °C was added dropwise diethylaminosulfur trifluoride (185 ml; 1.40 mol). The mixture was stirred at room temperature for 18 h. The reaction mixture was poured into ice and saturated NaHC03. The aqueous phase was extracted 3 times with DCM. The combined organic layers were dried over Na2S04, filtered and concentrated. The residue was purified by column chromatography (silica gel, hexane / EE (4 / 1)) to give 170 g of product.

[0160] C6H4 BrF2N (M = 208.0 g / mol) ESI-MS: 208 [M+H] +

[0161] 1H NMR (DMSO-d6, 400 MHz): δ = 8.65 (d, J = 1.3 Hz, 1 H), 7.91 - 8.08 (m, 1 H), 7.76 - 7.92 ppm (m, 1 H), 7.17 (t, J = 56 Hz, 1 H).

[0162] Example III: 5-(Difluoromethyl)-2-[2-(trimethylsilyl)ethynyl]pyridine

[0163]

[0164] To a mixture of Example II (120 g, 0.58 mol), bis(triphenylphosphine) palladium(II) chloride (20.2 g, 0.03 mol), copper(I) iodide (5.49 g, 0.03 mol) and triethylamine (250 mL, 1.73 mol) in 600 mL tetrahydrofuran at 0°C was added ethynyl-trimethyl-silane (160 mL, 1.15 mol) dropwise. The resulting mixture was stirred at room temperature for 18 h. The mixture was filtered through celite. The filter cake was washed with EtOAc. The filtrate was washed with water, dried over Na2S04, filtered and concentrated. Purification by column chromatography (silica gel, hexane / EE (19 / 1)) afforded 117 g of product.

[0165] C 11 H 13 F2Nsi (M = 225.3 g / mol) ESI-MS: 226 [M+H] +

[0166] 1 H NMR (DMSO-d6, 400 MHz): δ = 8.76 (d, J = 0.8 Hz, 1 H), 8.01 (dt, J = 8.1, 0.9 Hz, 1 H), 7.69 (d, J = 8.1 Hz, 1 H), 7.16 (t, J = 56 Hz, 1 H) 0.23 - 0.30 ppm (m, 9 H).

[0167] Example IV: 5-Difluoromethyl-2-ethynyl-pyridine

[0168]

[0169] To a solution of Example III (100.0 g, 0.42 mol) in 800 mL tetrahydrofuran) was added water (15.0 mL, 834 mmol). The resulting solution was cooled to 0 °C, then 1.0 M tetrabutylammonium fluoride in THF (143 mL; 0.50 mol) was added dropwise. After 1 h, TLC indicated the reaction was complete. Water was added, and the aqueous layer was extracted with diethyl ether 3 times. The combined organic layers were dried, filtered and carefully concentrated. The residue was purified by column chromatography (silica gel, hexane / DCM (1 / 1 to 0 / 1)) to give the product.

[0170] C8H5F2N (M = 153.1 g / mol) ESI-MS: 154 [M+H] +

[0171] 1 H NMR (DMSO-d6, 400 MHz): δ = 8.77 (d, J = 0.8 Hz, 1 H), 8.03 (br d, J = 8.1 Hz, 1 H), 7.72 (d, J = 8.1 Hz, 1 H), 7.17 (t, J = 56 Hz, 1 H) 4.50 ppm (s, 1 H).

[0172] Example V: 5-Difluoromethyl-2-(1 -trimethylsilanylmethyl-1 H-[1,2,3]triazol-4-yl)-pyridine

[0173]

[0174] To a solution of Example IV (50.0 g, 0.30 mol) in 1,5 L DMF was added copper (I) iodide (10.9 g, 0.06 mol) and N,N-diisopropylethylamine (50.360 mL, 0.29 mol), then trimethylsilylmethyl azide (50.6 mL, 0.34 mol) was added dropwise. The resulting mixture was stirred at room temperature for 24 h. The reaction was quenched by the addition of water / brine, then EtOAc was added, and the mixture was filtered through celite. The filtrate was extracted with EtOAc 3 times, dried over Na2S04, filtered and concentrated. Purification by column chromatography (silica gel, hexane / EE (3 / 1)), then the solid was triturated with pentane and dried gave 68.0 g of product.

[0175] C 12 H 16 F2N4Si (M = 282.4 g / mol) ESI-MS: 283 [M+H] +

[0176] R t (HPLC): 3.52 min (Method M)

[0177] 1 H NMR (DMSO-d6, 400 MHz): δ = 8.78 (s, 1 H), 8.52 (s, 1 H), 8.13-8.20 (m, 1 H), 8.05-8.12 (m, 1 H), 7.17 (t, J = 56 Hz, 1 H) 4.10 (s, 2 H), 0.11 ppm (s, 9 H).

[0178] Example VI 5-(5-Difluoromethyl-pyridin-2-yl)-3-methyl-3H-[1,2,3]triazole-4-carbaldehyde

[0179]

[0180] To a solution of Example V (93.0 g, 0.33 mol) in 1.86 L tetrahydrofuran was added water (11.9 ml, 0.66 mol). The resulting solution was cooled to 0 °C and tetrabutylammonium fluoride (395.2 ml, 0.40 mol) was added dropwise. The reaction mixture was stirred at 0 °C for 1.5 h. Water was added and the THF was evaporated. The formed precipitate was filtered, washed with water and dried to yield 51.0 g of product.

[0181] C9H8F2N4 (M = 210.1 g / mol) ESI-MS: 211 [M+H] +

[0182] 1 H NMR (DMSO-d6, 400 MHz): δ = 8.80 (d, J = 1.0 Hz, 1 H), 8.65 (s, 1 H), 8.14-8.19 (m, 1 H), 8.03-8.13 (m, 1 H), 7.17 (t, J = 56 Hz, 1 H) 4.13 ppm (s, 3 H).

[0183] Example VII: 5-(5-Difluoromethyl-pyridin-2-yl)-3-methyl-3H-[1,2,3]triazole-4-carbaldehyde

[0184]

[0185] To a solution of Example VI (40.0 g, 0.19 mol) in 1.2 L of tetrahydrofuran at -65 °C was added dropwise a 2.5 M solution of n-butyllithium (114.2 mL, 0.29 mol) in hexane. The resulting mixture was stirred at this temperature for 1.5 h. Then, N,N-dimethylformamide (147.4 mL, 1.90 mol) was added dropwise and then the reaction mixture was stirred at 0 °C for 30 min. The reaction was quenched by slow addition of an aqueous NH4CI solution. The aqueous layer was extracted 3 times with EtOAc. The combined organic layers were dried over Na2S04, filtered and concentrated. Purification by column chromatography (silica gel, DCM / EE (7 / 3 to 5 / 5)) followed by trituration with pentane afforded 19.9 g of product.

[0186] C9H8F2N4(M = 238.2 g / mol) ESI-MS: 239 [M+H] +

[0187] R t (HPLC): 2.68 min (Method M)

[0188] 1 H NMR (DMSO-d6, 400 MHz): d = 10.68 (s, 1 H), 8.92 (d, J = 0.8 Hz, 1 H), 8.34 (d, J = 8.3 Hz, 1 H), 8.22 (dd, J = 8.1, 1.0 Hz, 1 H), 7.23 (t, J = 56 Hz, 1 H), 4.29 ppm (s, 3H).

[0189] Example VIII : 5-(5-Difluoromethyl-pyridin-2-yl)-3-methyl-3H-[1,2,3]triazole-4-carbaldehyde

[0190]

[0191] Example VII (19.9 g, 0.08 mol) was dissolved in 199 mL of methanol and 99.5 mL of tetrahydrofuran. The resulting solution was cooled to 0 °C. Then sodium borohydride (6.32 g, 0.17 mol) was added portionwise and the reaction mixture was stirred at this temperature for 2 h. The reaction was quenched by addition of water. MeOH was evaporated and the resulting precipitate was collected by filtration, washed with water and dried. The solid was triturated with pentane to afford 19.4 g of product.

[0192] C9H8F2N4(M = 240.2 g / mol) ESI-MS: 241 [M+H] +

[0193] R t (HPLC): 3.52 min (Method N)

[0194] 1 H NMR (DMSO-d6, 400 MHz): d = 8.83 (s, 1 H), 8.22 (d, J = 8.1 Hz, 1 H), 8.11 (br d, J = 8.1 Hz, 1 H), 7.18 (t, J = 56 Hz, 1 H), 5.53 (s, 1 H), 5.09 (d, J = 3.8 Hz, 2 H), 4.11 ppm (s, 3 H).

[0195] Example IX.1 : 3-[3-(5-Difluoromethyl-pyridin-2-yl)-5-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-6-iodo- pyridazine

[0196]

[0197] To Example I (4.00 g, 16.6 mmol) in 50 mL THF was added sodium hydride (1.10 g, 25.0 mmol) and 3,6-diiodo-pyridazine (5.50 g, 17.0 mmol) and the reaction mixture was stirred at 80 °C overnight. The reaction mixture was evaporated. The residue was quenched with water and the product was extracted with DCM. The organic phases were combined and the organic phase was dried over MgS04and evaporated. The crude product was purified by column chromatography (silica gel, CH / EE (6 / 4)) to give 6.30 g of product.

[0198] C 14 H 11 F 2I N6O (M = 444.2 g / mol) ESI-MS: 445 [M+H] +

[0199] R t (HPLC): 0.57 min (Method A)

[0200] 1 H NMR (DMSO-d6, 400 MHz): d = 8.53-8.80 (m, 1 H), 8.33 (dt, J = 8.5, 1.1 Hz, 1 H), 7.96 (d, J = 9.1 Hz, 1 H), 7.22 (t, J = 52 Hz, 1 H), 6.95 (d, J = 9.1 Hz, 1 H), 5.95 (s, 2 H), 2.36-2.45 ppm (m, 3 H).

[0201] The following examples IX.2 to IX.4 referred to in the table below were prepared according to the general procedure described above for example IX.1.

[0202] The following examples IX.2 to IX.4 referred to in the table below were prepared according to the general procedure described above for example IX.1.Table of compounds of Examples IX.2 to IX.4 :

[0203]

[0204] The reaction conditions mentioned in the table below are for Examples IX.2 to IX.4.

[0205]

[0206] Example X.1: 1-(6-Chlorpyridazin-3-yl)-1H-pyrazole-4-carboxynitrile

[0207]

[0208] Add 3,6-dichloropyridazine (500 mg, 3.40 mmol) and potassium carbonate (1.40 g, 10.1 mmol) to 5 mL of 4-cyanopyrazole (312 mg, 3.40 mmol) in DMF, and stir the reaction mixture overnight at room temperature. Quench the mixture with ice water and filter the precipitate. Wash the residue with water and dry the separated solid in a vacuum drying oven to give 524 mg of product.

[0209] C8H4ClN5 (M=205.6g / mol)ESI-MS: 206[M+H] +

[0210] R t (HPLC): 0.80 min (Method C)

[0211] The following compounds were prepared according to the general procedure described in Example X.1 above:

[0212]

[0213]

[0214] Example XI: 3-Chloro-6-(5-methyl-1H-1,2,4-triazol-1-yl)pyridazine

[0215]

[0216] Dissolve 6-chloro-pyridazin-3-yl)-hydrazine (16.4 g, 113 mmol) and N-[1-dimethylamino-meth-(E)-ylidene]-acetamide (15.5 g, 136 mmol) in 164 mL acetic acid. Place the mixture in a preheated oil bath at 80 °C. Stir the reaction at this temperature for 30 min (TLC monitoring) and evaporate the acetic acid under vacuum. Dissolve the residue in EtOAc and slowly neutralize the organic layer with NaHC03(concentrated aqueous solution). Dry the organic layer over Na2S04and evaporate the solvent. Purify the product on silica gel using EtOAc / hexanes (3:1) as eluent. Obtain 10.2 g of 3-chloro-6-(5-methyl-[1,2,4]triazol-1-yl)-pyridazine as a cream colored solid.

[0217] Example XII: 1-(6-chloropyridazin-3-yl)-1H-imidazole-4-carboxylic acid methyl ester

[0218]

[0219] To sodium hydride (1.74 g, 43.6 mmol) in 50 mL DMF at 0 °C add 1H-imidazole-4- carboxylic acid methyl ester (5.00 g, 39.6 mmol) at 0 °C. Stir the reaction mixture for 30 min. To the reaction mixture add a solution of 3,6-dichloropyridazine (5.90 g, 39.6 mmol) in 30 mL DMF at 0 °C and stir the mixture for 20 h to reach room temperature. Quench the reaction mixture with water under ice cooling and filter the precipitate, wash and dry to obtain 3.90 g of product.

[0220] C9H7ClN4O2 (M = 238.6 g / mol) ESI-MS: 239 [M+H] +

[0221] 1 H NMR (400 MHz, DMSO-d6) d = 8.74 (d, J = 1.3 Hz, 1H), 8.72 (d, J = 1.0 Hz, 1H), 8.43 (d, J = 9.3 Hz, 1H), 8.25 (d, J = 9.3 Hz, 1H), 3.82 (s, 3H).

[0222] Example XIII: 1-(6-chloropyridazin-3-yl)-1H-imidazole-4-carboxylic acid

[0223]

[0224] To Example XII (3.80 g, 15.8 mmol) in 100 mL 1,4-dioxane was added 1 M NaOH (16.0 mL, 16.0 mmol) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice and 1 M HC1 (16.0 mL, 16.0 mmol). The precipitate was filtered, washed and dried to yield 3.30 g of product.

[0225] C8H5ClN4O2 (M = 224.6 g / mol) ESI-MS: 225 [M+H] +

[0226] R t (HPLC): 0.58 min (Method C)

[0227] Example XIV : 1 -(6-chloropyridazin-3-yl)-1 H-imidazole-4-carboxamide

[0228]

[0229] To Example VI (1.00 g, 4.50 mmol) in 10 mL DMF was added DIPEA (2.30 mL, 13.4 mmol) and TBTU (1.40 g, 4.50 mmol) and stirred at room temperature for 10 min. Ammonium bicarbonate (1.10 g, 13.4 mmol) was added and the reaction mixture was stirred at room temperature for 1 h. The mixture was quenched with ice and the precipitate was filtered, washed and dried to yield 0.80 g of product.

[0230] C8H6ClN5O (M = 223,6 g / mol) ESI-MS: 224 [M+H] +

[0231] R t (HPLC): 0,54 min (Method C)

[0232] Example XV: 1 -[6-(4-cyano-1 H-imidazol-1 -yl)pyridazin-3-yl]-1 H-imidazole-4-carbonitrile

[0233]

[0234] To 1 H-imidazole-4-carbonitrile (9.30 g, 99.9 mmol) in 100 mL DMF was added Example III (20.5 g, 99.9 mmol) and potassium carbonate (41.4 g, 299 mmol) and the reaction mixture was stirred at 50 °C for 18 h. 1 H-imidazole-4-carbonitrile (5.00 g, 53.7 mmol) was added and the mixture was stirred at 50 °C for 3 days.

[0235] The mixture was quenched with water and the precipitate was filtered to give 25.8 g of product after drying.

[0236] C 12 H6N8 (M = 262.2 g / mol) ESI-MS: 263 [M+H] +

[0237] R t (HPLC): 0.74 min (Method C)

[0238] Example XVI.1: 3-chloro-6-(4-chloro-1 H-pyrazol-1 -yl)pyridazine

[0239]

[0240] To 4-chloro-1 H-pyrazole (688 mg, 7.00 mmol) in 5 mL DMF was added 3,6-dichloro- pyridazine (500 mg, 3.36 mmol) and cesium carbonate (2.40 g, 7.38 mmol) and the reaction mixture was stirred at room temperature overnight. The mixture was quenched with water and the precipitate was filtered to give 686 mg of product.

[0241] C8H6N8 (M = 215.0 g / mol) ESI-MS: 216 [M+H] +

[0242] R t (HPLC): 0,51 min (Method A)

[0243] The following compounds were prepared according to the general procedure described above (Example XVI.1):

[0244]

[0245]

[0246]

[0247] Example XVII: 6-(pyrazin-2-yl)-2,3-dihydropyridazin-3-one

[0248]

[0249] To 2-oxoacetic acid hydrate (2.26 g, 25.0 mmol) in aqueous K2CO3(6.79 g in 30 mL water, 49.0 mmol) was added acetylpyrazine (3.00 g, 24.6 mmol). The mixture was stirred at room temperature for 6 h. Then acetic acid (12.9 mL, 221 mmol) and hydrazine hydrate (1.42 mL, 29.0 mmol) were added and the reaction mixture was refluxed for 2 h. The solution was cooled to room temperature and basified with K2CO3to pH 7. The precipitate was filtered, dried in an oven at 40 °C to obtain 1.29 g of product.

[0250] C8H6N4O (M = 174.1 g / mol) ESI-MS: 175 [M+H] +

[0251] R t (HPLC): 0.23 min (Method A)

[0252] Example XVIII: 3-chloro-6-(pyrazin-2-yl)pyridazine

[0253]

[0254] Example XVII (1.50 g, 6.03 mmol) in POCl3(5.00 mL, 53.6 mmol) was stirred at 100 °C for 1 h. The reaction mixture was evaporated and the residue was diluted with DCM under cooling. 10 mL of a saturated NaHCO3solution was added and this solution was added dropwise under stirring to an ice-cold saturated NaHCO3solution until the solution was neutral. After 30 min, the solution was filtered over celite and it was extracted with DCM. The organic layer was collected, dried and the solvent was evaporated. The product was purified by column chromatography (silica gel, CH / EE (1 / 1)) to obtain 570 mg of product.

[0255] C8H6ClN4 (M = 192.6 g / mol) ESI-MS: 193 [M+H] +

[0256] R t (HPLC): 0.33 min (Method A)

[0257] Preparation of final compounds

[0258] Example 1:5-[6-({1-[5-(difluoromethyl)pyridin-2-yl]-4-methyl-1H-1,2,3-triazol-5-yl}methoxy)pyridazin-3-yl]-1-methyl-1,2-dihydropyridin-2-one

[0259]

[0260] To 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,2-dihydropyridin-2-one (159 mg, 0.70 mmol) under argon was added Example IX.1 (250 mg, 0.60 mmol) in 1.5 mL methanol, 3 mL 1,4-dioxane, 2 M aqueous sodium carbonate solution (0.60 mL, 1.10 mmol) and Pd-PEPPSI (9.50 mg 0.01 mmol) and the reaction mixture was stirred at 100 °C for 3 h. The mixture was purified by preparative HPLC to obtain 96.1 mg of product.

[0261] C 20 H 17 F2N7O2 (M = 425.4 g / mol) ESI-MS: 426 [M+H] +

[0262] R t (HPLC): 0.58 min (Method D)

[0263] 1 H NMR (400 MHz, DMSO-d6) δ ppm 2.41-2.46 (m, 3 H) 3.48-3.57 (m, 3 H) 5.96-6.08 (m, 2 H) 6.47-6.58 (m, 1 H) 7.21 (t, J=56 Hz 1 H) 7.23 (s, 1 H) 7.95-8.06 (m, 1 H) 8.13-8.22 (m, 2 H) 8.29-8.38 (m, 1 H) 8.51 (d, J=2.66 Hz, 1 H) 8.65-8.71 (m, 1 H).

[0264] The following compounds were prepared according to the general procedure of Example 1 above:

[0265]

[0266]

[0267]

[0268]

[0269]

[0270]

[0271]

[0272]

[0273]

[0274]

[0275]

[0276]

[0277] For the example compounds, the reaction conditions in Table 2 were used.

[0278] Table 2: Reaction conditions for Examples 1-35

[0279]

[0280]

[0281] Example 36

[0282]

[0283]

[0284] To Example I (50.0 mg, 0.20 mmol) and Example XIV (46.5 mg, 0.20 mmol) in 2 mL DMSO was added dropwise a 2 mol / L solution of sodium tert-pentoxide in Me-THF (83.9 μL, 0.20 mmol) at 0 °C. The reaction mixture was stirred at room temperature overnight, then at 50 °C overnight, and then at 75 °C for 3 days. The mixture was purified by preparative HPLC to obtain 3.20 mg of product.

[0285] C 18 H 15 F2N9O2 (M = 427.4 g / mol) ESI-MS: 428 [M+H] +

[0286] R t (HPLC): 0.77 min (Method C)

[0287] The following compounds were prepared according to the general procedure of Example 36 above:

[0288] The following compounds were prepared according to the general procedure of Example 36 above:

[0289]

[0290] For example compounds 37-41, the reaction conditions in the following table were used. Table of reaction conditions for example compounds 37-41

[0291]

[0292]

[0293] Example 42: 1 -[6-({1 -[5-(difluoromethyl)pyridin-2-yl]-4-methyl- 1 H-1,2,3-triazol-5-yl}methoxy)pyridazin-3-yl]- 1 H-imidazole-4-carbonitrile

[0294]

[0295] To example I (200 mg, 1.00 mmol) in 5 mL ACN was added cesium carbonate (814 mg, 2.00 mmol) and example XV (273 mg, 1.00 mol) and the mixture was stirred at 90 °C overnight. The reaction mixture was quenched with water and the precipitate was filtered to obtain the crude product. The crude product was purified by silica gel column (CH / EE) and finally recrystallized in MeOH / EE / ether to obtain 151 mg of product.

[0296] C 18 H 13 F2N9O (M = 409.3 g / mol) ESI-MS: 410 [M+H] +

[0297] R t (HPLC): 0.50 min (Method A)

[0298] 1 H NMR (400 MHz, DMSO-d6) δ ppm 2.34 - 2.48 (m, 3 H) 5.97 - 6.14 (m, 2 H) 7.22 (t, J=56 Hz, 1 H) 7.50 - 7.64 (m, 1 H) 8.16 - 8.19 (m, 1 H) 8.19 - 8.21 (m, 1 H) 8.31 - 8.43 (m, 1 H) 8.67 (d, J=1.14 Hz, 1 H) 8.73 (d, J=1.27 Hz, 1 H) 8.90 - 8.95 (m, 1 H).

[0299] The following compounds 43-47 in the table below were prepared according to the general procedure of example 42 described above:

[0300] Table of compounds 43-47

[0301]

[0302]

[0303] For example compounds 43-47, the reaction conditions in the table below were used. Table of reaction conditions for example compounds 43-47

[0304]

[0305] Example 48: 3-({4-[5-(difluoromethyl)pyridin-2-yl]-1-methyl-1H-1,2,3-triazol-5-yl}methoxy)-6-(5- methyl-1H-1,2,4-triazol-1-yl)pyridazine

[0306]

[0307] To example VIII (200 mg, 0.83 mmol) and example XI (163 mg, 0.83 mmol) in 10 mL of dioxane was added sodium tert-pentoxide (101 mg, 0.92 mmol). The reaction mixture was stirred at 90 °C overnight, then at room temperature over the weekend. The reaction mixture was diluted with water and the filtrate was precipitated. The crude solid was recrystallized in MeOH to obtain 212 mg of product.

[0308] C 17 H 15 F2N9O (M = 399.4 g / mol) ESI-MS: 400 [M+H] +

[0309] R t (HPLC): 0.46 min (Method A)

[0310] The following compounds 49 and 50 were prepared according to the general procedure of example 48 described above:

[0311]

[0312] For example compounds 49-50, the reaction conditions in the table below were used.

[0313] Table of reaction conditions for example compounds 49-50 Table

[0314]

[0315] Example 51:3-(4-chloro-1H-pyrazol-1-yl)-6-({4-[5-(difluoromethyl)pyridin-2-yl]-1-methyl-1H-1,2,3-triazol-5-yl}methoxy)pyridazine

[0316]

[0317] Sodium hydride (21.8 mg, 0.50 mmol) was added to 2 mL of DCM containing Example VIII (100 mg, 0.42 mmol) and Example XVI.1 (89.5 mg, 0.42 mmol). The reaction mixture was stirred overnight at room temperature. The reaction mixture was then purified directly by preparative HPLC to obtain 41.6 mg of product.

[0318] C 17 H 13 ClF2N8O (M=418.8g / mol)ESI-MS: 397[M+H] +

[0319] R t (HPLC): 0.86 min (Method F)

[0320] The following compounds were prepared according to the general procedure described above (Example 51):

[0321]

[0322]

[0323] For compounds 52-53 in Examples, the reaction conditions in the table below were used.

[0324] Reaction conditions of compounds 52-53 in Examples Table

[0325]

[0326] Example 54: 3-({1-[5-(difluoromethyl)pyridin-2-yl]-4-methyl-1H-1,2,3-triazol-5-yl}methoxy)-6-(4-fluoro-1H-pyrazol-1-yl)pyridazine

[0327]

[0328] To 4-fluoro-1H-pyrazole (6.00 mg, 0.10 mmol) in 1 mL dioxane under argon was added Example IX.1 (30.0 mg, 0.10 mmol), copper(I) iodide (5.10 mg, 0.03 mmol), potassium phosphate (57.3 mg, 0.30 mmol) and (1R,2R)-N,N'-dimethyl-1,2-cyclohexanediamine (8.50 μL, 0.05 mmol). Then 100 μL 25% ammonia was added and the mixture was stirred for another 15 min. The reaction mixture was filtered over an alux column and a SPE-thiol cartridge and then it was purified by preparative HPLC to obtain 20.2 mg product.

[0329] C 17 H 13 F3N8O (M = 402.3 g / mol) ESI-MS: 403 [M+H] +

[0330] R t (HPLC): 0,84 min (Method F)

[0331] The following compound 55 was prepared according to the general procedure of example 54 described above:

[0332]

[0333] For example compound 55 the following reaction conditions were used.

[0334]

[0335] Example 56: 3-({1-[5-(Difluoromethyl)pyridin-2-yl]-4-methyl-1H-1,2,3-triazol-5-yl}methoxy)-6- (pyrazin-2-yl)pyridazine

[0336]

[0337] To 2-tributylstannylpyrazine (83.0 mg, 0.23 mmol) in 2 mL dioxane under argon was added Example IX.2 (53.0 mg, 0.15 mmol), cesium fluoride (46.0 mg, 0.30 mmol) and xphos (26.0 mg, 0.03 mmol). The reaction mixture was purified by preparative HPLC to obtain 17.0 mg product.

[0338] C 18 H 14 F2N8O (M = 396.3 g / mol) ESI-MS: 397 [M+H] +

[0339] R t (HPLC): 0, 92 min (Method G)

[0340] 1 H NMR(400MHz,DMSO-d6)δppm 2.47(s,3H)6.11(s,2H)7.22(t,J=56Hz,1H)7.35(d,J=9.25Hz,1H)8.20(d,J=8.49Hz,1H)8.32 -8.37(m,1H)8.39(d,J=9.25Hz,1H)8.67(d,J=1.14Hz,1H)8.74-8.84(m,2H)9.55-9.66(m,1H).

[0341] Biological Examples

[0342] Assay A: In vitro inhibition 3 H-flumazenil 3 H-Ro 15-1788) binding to human GABA A a5p3y 2s receptors HEK cells

[0343] The benzodiazepine modifier unit can be selectively replaced with an antagonist. 3 H-Flumazenil labeling.

[0344] According to reports, 3 H-flumazenil's affinity for different subunit combinations is shown for α1β2γ2; α2β2γ2; α3β2γ2 and α5β2γ2. 2s The receptors were 1.0 nM, 1.1 nM, 1.5 nM and 0.4 nM, and 107 nM and 90 nM for α4β2γ2 and α6β2γ2 receptors, respectively (see Sieghart; Pharmacol. Rev. 1995 47 181-234).

[0345] Regarding the binding of 3H-flumazenil, the mutation of α5β3γ 2s GABA A The pharmacology of the receptor is similar to that of the wild-type receptor.

[0346] Cell culture and membrane preparation

[0347] Stable expression of recombinant human GABA A α5β3γ 2s HEK-293 cell lines containing the receptor (plasmid H46 / E9 / B10) were seeded in T175 polystyrene flasks or roller flasks (1700 cm²). 2 Fisher Scientific CCI-431191) and in Durbecco's Modified Eagle Medium (DMEM) (containing GlutaMAX) TM, supplemented with 10% fetal bovine serum and the following antibiotics: one or both of hygromycin B (50 pg / ml; gamma 2 subunit) or G418 (0.5 mg / ml; omega 5 subunit) and grown (37°C, 5% CO2).

[0348] When the cultures reached confluency, the DMEM was removed and the cells were washed once in Dulbecco's Phosphate Buffered Saline (DPBS) (10 ml for T175 flasks; 50 ml for roller bottles). After the addition of DPBS to the cultures (10 ml for T175 flasks; 100 ml for roller bottles) over approximately 5 min, the cells were easily dislodged from the surface by gently rocking or tapping the flasks. The cell suspension was transferred to Falcon tubes and centrifuged at 23,500 x g for 10 min at 2°C. The pellet was washed once in 15 ml Tris-citrate buffer (50 mM, pH 7.1) using an Ultra-Turrax homogenizer and centrifuged at 27,000 x g for 10 min at 2°C. The washed pellet was resuspended in 15 ml Tris-citrate buffer and frozen at -80°C until the day of the binding experiment.

[0349] Assay

[0350] On the day of the experiment, the cell membrane preparation was thawed and centrifuged at 27,000 x g for 10 min at 2°C. The pellet was resuspended in Tris-citrate buffer to 15-50 pg protein / assay using an Ultra-Turrax homogenizer and then used for the binding assay.

[0351] Aliquots of 500 μl cell suspension were added to 25 μl test compound solution and 25 μl 3 H-flumazenil (1 nM, final concentration) mixed and incubated for 40 min at 2°C. Non-specific binding was determined using chlordiazepoxide (1 μM, final concentration).

[0352] All dilutions and incubations of test compounds were performed in glass vials / 96-well plates. Test compounds and 3 Solutions of test compounds were prepared as 22x the desired final concentration. Compounds were dissolved in 100% DMSO (10 mM stock), diluted in 48% ethanol-water, and tested in triplicate at serial 1 :3 or 1 : 10 dilutions. When screening large numbers of compounds, only one concentration of each compound was tested in a single well. Reference compounds were not routinely included, but for each experiment performed, total binding and non-specific binding were compared to data obtained during assay validation.

[0353] The union may be terminated in the following ways:

[0354] 1) Use a Brandel cell harvester to quickly filter the cells onto a Whatman GF / C glass fiber filter, then wash 5 times with 1 ml of ice-cold buffer; or 2) Use a Tomtec cell harvester to quickly filter the cells onto a UniFilter GF / C glass fiber filter plate, then wash with approximately 5 ml of ice-cold buffer.

[0355] The amount of radiation on the filter is determined using the following method through conventional liquid scintillation counting:

[0356] 1) Tri-Garb TM Counters (PerkinElmer Life and Analytical Sciences), used for individual large filters, or

[0357] 2) Topcount TM Counter (PerkinElmer Life and Analytical Sciences), used for 96-well filter plates. Specific binding is total binding minus non-specific binding.

[0358] Calculation

[0359] In calculating IC 50 (make 3 Before H-flumazenil can achieve 50% specific binding inhibition at the test compound concentration (μM), 25%–75% specific binding inhibition must be obtained.

[0360] IC testing of compounds 50 The value is determined based on the following equation:

[0361] B = 100 - (100 * C) n / (IC 50 n +C n ))

[0362] Where B is the percentage of total specific binding; c is the concentration of the test compound; and n is the Hill coefficient. For screening purposes, n is set to 1. The IC50 was calculated from the concentration response curve using a nonlinear regression method with the curve fitting program GraphPad Prism. 50 value.

[0363] The equations of Cheng and Prusoff can be used to obtain IC 50 Calculate the Ki value of the test compound:

[0364] K = IC 50(1 + L / K d )

[0365] wherein 3 H is the K d of H-flumazenil is 0.36 nM and L is the measured concentration of H-flumazenil in the inhibition assay. 3 H-flumazenil.

[0366] Results

[0367] The observed potency in Assay A for WO 2020 / 016433 example compounds 1, 13, 10 and 28 and the present example compounds 42, 56, 5 and 55 is shown in the table below.

[0368]

[0369]

[0370]

[0371]

[0372] Determination of B: α5β2γ2GABA A In vitro evaluation of receptor regulation.

[0373] Modulation efficacy of compounds of Formula (I) was determined as electrophysiological recordings in oocyte using the two-electrode voltage clamp (TEVC) technique. Oocytes were injected with cRNA of human GABA A receptor subunits a5, b2 and g2 in a ratio of 3:1:3 and the modulation efficacy was evaluated by co-application with a submaximal EC 5-20 GABA concentration (0.5 mM) referred to as GABA control. As a standard, compounds were tested at five concentrations (3.16, 0.316, 0.0316, 0.00316 and 0.000316 mM) on each oocyte starting from the lowest concentration. Peak current amplitudes, subtracted from background, were normalized to the corresponding GABA control current, converted into % change and the change + / - S.E.M. was plotted against increasing compound concentration. The plotted data points were fitted to an empirical Hill equation using non-linear regression. From this fitting procedure, the 95% confidence interval for the maximal efficacy (bottom) and the potency (Log EC 50 ) were derived.

[0374]

[0375]

[0376] These data show that the compounds of the present application show strong negative modulation of target engagement and GABA receptor function. The data also show that the compounds, in particular compared to the compounds known from WO 2020 / 016433, have improved properties in terms of 5R binding, which means lower effective doses of the compounds for disease treatment (see also: Ballard, T.M. et al. (2009). RO4938581, a novel cognitive enhancer acting at GABA A 5R binding, which means lower effective doses of the compounds for disease treatment (see also: Ballard, T.M. et al. (2009). RO4938581, a novel cognitive enhancer acting at GABA A containing receptors. Psychopharmacology (2009) 202:207-223; J. Pharmacol. Exp. Ther. (2006) 316:1335-1345).

[0377] Evaluation of efflux in Madin-Darby canine kidney (MDCK) cells transfected with 30 human MDR1 genes to assess brain penetration (Drug Metabolism and Disposition February 2008, 36(2) 268-275; DOI: https: / / doi.org / 10.1124 / dmd.107.017434)

[0378] The apparent permeability coefficients (PE) of the compounds across MDCK-MDR1 cell monolayers were measured (pH 7.4, 37°C) in apical to basolateral (AB) and basolateral to apical (BA) transport directions. AB permeability (PEAB) represents drug absorption from blood into the brain, and BA permeability (PEBA) represents drug efflux from outside the brain back into the blood via both passive permeability and active transport mechanisms mediated by efflux and uptake transporters expressed on MDCK-MDR1 cells, mainly by overexpressed human MDR1 P-gp. Compounds were classified into permeability / absorption categories by comparing AB permeability to that of reference compounds with known in vitro permeability and oral absorption in humans. Permeability that is the same or similar in both transport directions indicates passive permeation, while vectorial permeability points to additional active transport mechanisms. PEBA higher than PEAB indicates involvement of active efflux mediated by MDR1 P-gp. Active transport is concentration-dependent saturated.

[0379] MDCK-MDR1 cells (1-2 x 10e5 cells per 1 cm2area) were seeded on filter inserts (Costar transwell polycarbonate or PET filters, 0.4 pm pore size) and incubated (DMEM) for 7 days. Subsequently, MDR1 expression was enhanced by incubating the cells for 2 days in complete medium with 5 mM sodium butyrate. Compounds were dissolved in an appropriate solvent (e.g. DMSO, 1-20 mM stock solution). The stock solution was diluted with HTP-4 buffer (128.13 mM NaCl, 5.36 mM KCl, 1 mM MgS04, 1.8 mM CaCl2, 4.17 mM NaHC03, 1.19 mM Na2HP04x 7 H20, 0.41 mM NaH2P04x H20, 15 mM HEPES, 20 mM glucose, 0.25% BSA, pH 7.4) to prepare the transport solution (0.1-300 mM compound, final DMSO <= 0.5%). The transport solution (TL) was applied to the apical or basolateral donor side, respectively, to measure A-B or B-A permeability (3 filter replicates). The receiver side contained the same buffer as the donor side. Samples were collected from the donor at the beginning and end of the experiment and also from the receiver side at different time intervals over 2 hours for concentration measurement by HPLC-MS / MS or scintillation counting. The sampled receiver volume was replaced with fresh receiver solution

[0380]

[0381] These data show that the compounds of the application have excellent brain penetration properties and a low efflux ratio from the brain ventricles. Metabolic stability was assessed in human liver microsomes (human MST)

[0382] The metabolic stability of the compounds according to the application can be investigated as follows:

[0383] The metabolic degradation of the test compound was determined with pooled human liver microsomes at 37°C. The final incubation volume / time point of 100 pL contained TRIS buffer pH 7.6 (at room temperature) (0.1 M), MgCl2(5 mM), microsomal protein (1 mg / mL) and the test compound at a final concentration of 1 mM. After a short pre-incubation period at 37°C, the reaction was started by the addition of reduced form of beta-nicotinamide adenine dinucleotide phosphate (NADPH, 1 mM) and terminated by transferring aliquots to solvent after different time points. After centrifugation (10000 g, 5 min), the amount of parent compound in the supernatant was determined by LCMS / MS in aliquots. The half-life (t1 / 2) was determined by the slope of the semi-logarithmic plot of the concentration-time curve.

[0384] Example Human MST t1 / 2[min] Example Human MST t1 / 2>[min] 1 >130 28 >130 3 >130 29 97 4 40 30 >130 5 83 31 127 6 116 32 78 7 >130 33 98 8 >130 35 >130 9 101 37 129 17 >130 39 >130 18 >130 48 >130 20 >130 49 >130 22 >130 50 130 23 >130 52 >130 24 62 53 >130 25 >130 56 >130

[0385] Given its regulation of GABA containing the α5 subunit A The ability to activate receptors and their favorable pharmacokinetic properties, compounds of general formula (I) according to the invention, or physiologically acceptable salts thereof, are suitable for the treatment and / or prophylactic treatment of all diseases or conditions that may be affected by the regulation of GABAA receptors containing α5 subunits. Therefore, compounds according to the invention, including their physiologically acceptable salts, are particularly suitable for the prevention or treatment of diseases, especially acute neurological disorders, chronic neurological disorders, cognitive impairment, Alzheimer's disease, memory deficits, schizophrenia, positive, negative and / or cognitive symptoms associated with schizophrenia, cognitive impairment associated with schizophrenia, bipolar disorder, autism, Down syndrome, neurofibromatosis type I, postoperative cognitive decline, sleep disorders, circadian rhythm disorders, amyotrophic lateral sclerosis (ALS), AIDS-related dementia, psychotic disorders, substance-induced psychotic disorders, anxiety disorders, generalized anxiety disorder, panic disorder, paranoid disorder, obsessive-compulsive disorder, acute stress disorder, drug addiction, movement disorders, Parkinson's disease, restless legs syndrome, cognitive impairment, and multiple infarctions. Dementia, mood disorders, depression, major depressive disorder, neuropsychiatric disorders, psychosis, attention deficit hyperactivity disorder, neuropathic pain, stroke, attention deficit disorder, eating disorders, anorexia, anorexia nervosa, cachexia, weight loss, muscle atrophy, pain disorders, chronic pain, nociceptive pain, postoperative pain, osteoarthritis pain, rheumatoid arthritis pain, musculoskeletal pain, burn pain, eye pain, pain due to inflammation, pain due to fracture, hyperalgesia, neuropathic pain, herpes-related pain, HIV-related neuropathic pain, traumatic nerve injury, recovery after traumatic brain injury, post-stroke pain, post-ischemic pain, fibromyalgia, chronic headache, migraine, tension headache, diabetic neuropathic pain, phantom limb pain, visceral pain, and skin pain.

[0386] The compounds according to the invention, including their physiologically acceptable salts, are even more suitable for treating, in particular, cognitive impairment, postoperative cognitive decline, Alzheimer's disease, schizophrenia, positive, negative and / or cognitive symptoms associated with schizophrenia, cognitive impairment associated with schizophrenia, cognitive deficits associated with Down syndrome, cognitive deficits associated with autism, cognitive deficits associated with neurofibromatosis type I, or post-stroke cognitive deficits.

[0387] In another aspect of the invention, the invention relates to a method for treating or preventing the aforementioned diseases and symptoms, the method comprising administering to a human an effective amount of a compound of general formula (I) or a pharmaceutically acceptable salt thereof.

[0388] The daily dose range of compounds of general formula (I) that can be applied is generally from 0.1 to 1000 mg, preferably from 1 to 500 mg, administered orally 1 to 4 times daily in each case.

[0389] Each dosage unit can conveniently contain from 0.1 to 500 mg, preferably 1 to 100 mg.

[0390] The actual pharmaceutically effective dose or therapeutic dose will, of course, depend on factors known to those skilled in the art, such as the patient's age and weight, route of administration, and severity of disease. In any case, the dosage and manner of administration of the combination will allow for the delivery of a pharmaceutically effective dose based on the patient's unique condition.

[0391] Suitable formulations for use with the compound of formula (I) (including its pharmaceutically acceptable salts) will be apparent to those skilled in the art, and include, for example, tablets, pills, capsules, suppositories, lozenges, sugar tablets, solutions, syrups, elixirs, capsules, injections, inhalers, powders, etc. The content of one or more pharmaceutically active compounds should vary from 0.1 to 95 wt.%, preferably 5.0 to 90 wt.%, of the composition as a whole.

[0392] Suitable tablets can be obtained, for example, by mixing one or more compounds according to Formula I with known excipients, such as inert diluents, carriers, disintegrants, adjuvants, surfactants, binders, and / or lubricants. Tablets may also consist of several layers.

[0393] For this purpose, compounds of formula I prepared according to the present invention can be formulated, optionally together with other active substances, with one or more inert conventional carriers and / or diluents, such as corn starch, lactose, glucose, microcrystalline cellulose, magnesium stearate, citric acid, tartaric acid, water, polyvinylpyrrolidone, water / ethanol, water / glycerol, water / sorbitol, water / polyethylene glycol, propylene glycol, cetearyl alcohol, carboxymethyl cellulose or fatty substances such as stearates or suitable mixtures thereof.

[0394] The compounds according to the application can also be used in combination with other active substances, in particular for the treatment and / or prevention of the above-mentioned diseases and disorders. A list of examples is: donepezil, memantine, acetazolamide, carbamazepine, eslicarbazepine acetate, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, brivaracetam, nitrazepam, oxcarbazepine, pregabalin, piracetam, phenobarbital, phenytoin, pregabalin, primidone, valproate, stiripentol, tiagabine, topiramate, vigabatrin, zonisamide, levodopa, carbidopa, haloperidol, loxapine, thioridazine, molindone, thiothixene, fluphenazine, mesoridazine, trifluoperazine, perphenazine, chloφromazine, aripiprazole, asenapine maleate, clozapine, iloperidone, lurasidone, olanzapine, paliperidone, quetiapine, risperidone, ziprasidone and zotepine.

[0395] The dosage of the combination partners mentioned above is generally 1 / 5 of the minimum normally recommended dose to 1 / 1 of the normally recommended dose.

[0396] Thus, in another aspect, the present application relates to the use of a compound according to the present application, or a pharmaceutically acceptable salt thereof, in combination with at least one of the above-mentioned active substances as combination partners for the preparation of a pharmaceutical composition for the treatment or prophylaxis of the above-mentioned diseases or disorders.

[0397] The use of a compound according to the present application in combination with another active substance can be simultaneous or at staggered times, but particularly within a short time interval. If they are administered simultaneously, both active substances are given to the patient together; whereas if they are used at staggered times, both active substances are given to the patient within a time period of less than or equal to 12 hours, particularly less than or equal to 6 hours.

[0398] Thus, in another aspect, the present application relates to a pharmaceutical composition comprising a compound according to the present application, or a pharmaceutically acceptable salt thereof, and at least one of the above-mentioned active substances as combination partners, optionally together with one or more inert carriers and / or diluents.

[0399] The compounds according to the present application can be present together in one formulation, such as a tablet or capsule, or separately in two identical or different formulations, such as in the form of a so-called kit-of-parts.

Claims

1. A compound having formula (I) or a pharmaceutically acceptable salt thereof. in: Xa and Xb are distinct from each other and represent C or N, and R1 is an unsubstituted 2-pyridone or a 2-pyridone substituted with a halogen or substituted with a methyl or ethyl group on a nitrogen atom.

2. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein the halogen is fluorine.

3. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein R1 is 4. A compound or a pharmaceutically acceptable salt thereof, said compound being selected from:

5. The compound of claim 4 or a pharmaceutically acceptable salt thereof, wherein the compound is compound 1.

6. The compound of claim 4 or a pharmaceutically acceptable salt thereof, wherein the compound is compound 20.

7. The compound of claim 4 or a pharmaceutically acceptable salt thereof, wherein the compound is compound 21.

8. The compound or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 7, used as a pharmaceutical agent.

9. A pharmaceutical preparation made from a compound according to any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof.

10. A pharmaceutical composition comprising at least one compound according to any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers.

11. The pharmaceutical composition of claim 10, wherein the pharmaceutical composition is used to treat or prevent acute neurological disorders, chronic neurological disorders, cognitive impairment, Alzheimer's disease, memory deficits, schizophrenia, positive, negative and / or cognitive symptoms associated with schizophrenia, cognitive impairment associated with schizophrenia, bipolar disorder, autism, Down syndrome, neurofibromatosis type I, postoperative cognitive decline, sleep disorders, circadian rhythm disorders, amyotrophic lateral sclerosis (ALS), AIDS-related dementia, substance-induced psychotic disorders, generalized anxiety disorder, panic disorder, paranoid disorder, obsessive-compulsive disorder, acute stress disorder, drug addiction, movement disorders, Parkinson's disease, restless legs syndrome, cognitive deficits, and multi-infarct dementia. Mood disorders, depression, major depressive disorder, neuropsychiatric disorders, psychosis, attention deficit hyperactivity disorder, stroke, attention deficit disorder, eating disorders, anorexia, anorexia nervosa, cachexia, weight loss, muscle atrophy, chronic pain, nociceptive pain, postoperative pain, osteoarthritis pain, rheumatoid arthritis pain, musculoskeletal pain, burn pain, eye pain, pain due to inflammation, pain due to fracture, hyperalgesia, neuropathic pain, herpes-related pain, HIV-related neuropathic pain, traumatic nerve injury, recovery after traumatic brain injury, post-stroke pain, post-ischemic pain, fibromyalgia, chronic headache, migraine, tension headache, diabetic neuropathic pain, phantom limb pain, visceral pain, and skin pain.

12. The pharmaceutical composition according to claim 10, wherein the pharmaceutical composition is used to treat or prevent pain disorders, psychotic disorders, and anxiety disorders.

13. The pharmaceutical composition according to any one of claims 10 to 12, wherein the pharmaceutical composition comprises 0.1 to 1000 mg of the compound according to any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof in a therapeutically effective amount.

14. The pharmaceutical composition according to any one of claims 10 to 12, wherein the pharmaceutical composition comprises a therapeutically effective amount of 1 to 500 mg of the compound according to any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof.

15. The compound of any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of any one of claims 10 to 12, for the prevention or treatment of cognitive impairment, postoperative cognitive decline, Alzheimer's disease, schizophrenia, positive, negative and / or cognitive symptoms associated with schizophrenia, cognitive impairment associated with schizophrenia, cognitive deficits associated with Down syndrome, cognitive deficits associated with autism, cognitive deficits associated with neurofibromatosis type I, or post-stroke cognitive deficits.

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