Triazoles as NR2B receptor inhibitors

Provided here in are compounds of Formula I having the structure: Also provided herein are compositions comprising compounds of Formula I and methods of using compounds of Formula I for the treatment of disorders, diseases or conditions mediated by GluN2B receptors.

TECHNICAL FIELD

The invention relates to 1,2,3-triazole derivatives and the use of these compounds for the treatment of various diseases and conditions.

BACKGROUND OF THE INVENTION

Glutamate is one of the major excitatory neurotransmitters that is widely spread in the brain. First indication of its role as an excitatory messenger was in the 1950's when it was observed that intravenous administration of glutamate induces convulsions. However, the detection of the whole glutamatergic neurotransmitter system with its various receptors did not take place before the 1970's and 1980's when numerous antagonists were developed or, as in the case of PCP and ketamine, were identified as antagonists. Finally, in the 1990's molecular biology provided the tools for the classification of the glutamatergic receptors.

Glutamate is a main excitatory neurotransmitter in the mammalian central nervous system and N-methyl-D-aspartate (NMDA) receptors are a subtype of ionotropic glutamate receptors that mediate excitatory synaptic transmission in the brain. NMDA receptors are ubiquitously distributed throughout the brain and play a key role in synaptic plasticity, synaptogenesis, excitotoxicity, memory acquisition and learning. NMDA receptors are distinct from other major subtypes of ionotropic glutamate receptors (AMPA and kainate receptors) in that they are blocked by Mg2+at resting membrane potentials, are highly Ca2+permeable, and require co-activation by two distinct neurotransmitters: glutamate and glycine (or D-serine) (Traynelis S F et al.,Pharmacol Rev.2010; 62(3):405-96). The influx of Ca2+through NMDA receptors triggers signaling cascades and regulates gene expression that is critical for different forms of synaptic plasticity including both long-term potentiation of synapse efficacy (LTP) (Berberich S et al.,Neuropharmacology2007; 52(1):77-86) and long-term depression (LTD) (Massey, P V et al.,J Neurosci.2004 8; 24(36):7821-8).

The vast majority of the mammalian NMDA receptors form a heterotetramer made of two obligatory GluN1 units and two variable GluN2 receptor subunits encoded by the GRIN1 gene and one of four GRIN2 genes, respectively. One or both GluN2 subunits can be potentially replaced by a GluN3A or a GluN3B subunit. The GRIN1 gene product has 8 splice variants while there are 4 different GRIN2 genes (GRIN2A-D) encoding four distinct GluN2 subunits. The glycine binding site is present on the GluN1 subunit and the glutamate binding site is present on the GluN2 subunit.

The GluNR2 subunits play a dominant role in determining the functional and pharmacological properties of the NMDA receptor assembly and exhibit distinct distribution in different areas of the brain. For instance, GluN2B subunits are expressed primarily in the forebrain in the adult mammalian brain (Paoletti P et al.,Nat Rev Neurosci.2013; 14(6):383-400; Watanabe M et al.,J Comp Neurol.1993; 338(3):377-90) and are implicated in learning, memory processing, mood, attention, emotion and pain perception (Cull-Candy S et al.,Curr Opin Neurobiol.2001; 11(3):327-35).

SUMMARY OF THE INVENTION

Provided herein are compounds which inhibit the NR2B receptor.

In one aspect, provided herein are compounds, and pharmaceutically acceptable salts, solvates, or N-oxides thereof, having the structure of Formula (I):

The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, solvate, or N-oxide thereof for use in medicine, and optionally a pharmaceutically acceptable carrier. The pharmaceutical composition may be used in human or veterinary medicine.

The present invention further provides a method of treating disorders associated with NMDA hyperactivity, most preferably with NR2B hyperactivity, the method comprising administering to a patient in need thereof a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, solvate, or N-oxide thereof.

The present invention also provides a method of treating a central nervous system disorder in a patient in need thereof comprising, administering to said patient a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, solvate, or N-oxide thereof.

The present invention also provides a compound for use in any of the methods described herein. The present invention further provides use of a compound for the preparation of a medicament for use in any of the methods described herein.

DETAILED DESCRIPTION

Exemplary Compounds and Compositions

The present invention provides, inter alia, a compound of Formula (I):

or pharmaceutically acceptable salts, solvates, or N-oxides thereof; wherein:Het represents one of the following heterocyclic ring structures:

In specific embodiments, one of R1and R2does not represent hydrogen, or both of R1and R2do not represent hydrogen. When different from hydrogen, R1and R2are preferably located at a meta- or at the para-position of the phenyl ring for example, the phenyl ring may contain substituents R1and/or R2different from H at position 3, 4, 3 and 4, or 3 and 5, and the substituents at all other positions are H.

In one embodiment Het may represent

wherein A represents N or C—R4; B represents C—R4; R4and R5in each case independently representhydrogen,amino,—F, Cl,C1-3alkyl, straight or branched, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, hydroxy, and/or C1-3alkoxy, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms,C1-3alkoxy, straight or branched, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms,C3-6cycloalkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, andC3-6cycloalkyl-C1-3alkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms.

In other embodiments Het may represent:

R3representshydrogen,C1-3alkyl, straight or branched, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, hydroxy, and/or C1-3alkoxy, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms,C3-6cycloalkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, andC3-6cycloalkyl-C1-3alkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, and
R4and R5independently from each other representhydrogen,amino,F, Cl,C1-3alkyl, straight or branched, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, hydroxy, and/or C1-3alkoxy, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms,C1-3alkoxy, straight or branched, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms,C3-6cycloalkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms, andC3-6cycloalkyl-C1-3alkyl, optionally substituted with at least one halogen atom, e.g. with 1, 2 or 3 halogen atoms.

The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, solvate, or N-oxide thereof for use in medicine, and optionally a pharmaceutically acceptable carrier. The pharmaceutical composition may be used in human or veterinary medicine.

Certain Definitions

The term “alkyl” refers to a straight- or branched-chain alkyl group having from 1 to 12 carbon atoms in the chain. In some embodiments, an alkyl group is a C1-C6alkyl group. In some embodiments, an alkyl group is a C1-C4alkyl group. Examples of alkyl groups include methyl (Me) ethyl (Et), n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl (tBu), pentyl, isopentyl, tert-pentyl, hexyl, isohexyl, and groups that in light of the ordinary skill in the art and the teachings provided herein would be considered equivalent to any one of the foregoing examples. In some embodiments, alkyl refers to straight or branched chain hydrocarbon groups. Specific examples in these embodiments are methyl, ethyl, propyl (e.g., n-propyl and isopropyl), butyl (e.g., n-butyl and t-butyl) hexyl and the like.

The term “haloalkyl” refers to a straight- or branched-chain alkyl group having from 1 to 12 carbon atoms in the chain and having at least one of the hydrogens replaced with a halogen. In some embodiments, a haloalkyl group is a C1-C6haloalkyl group. In some embodiments, a haloalkyl group is a C1-C4haloalkyl group. One exemplary substitutent is fluoro. Preferred substituted alkyl groups of the invention include trihalogenated alkyl groups such as trifluoromethyl groups. Haloalkyl includes and is not limited to CF3, CH2F, —CHF2, —CH2Cl, —CH2—CF3, and the like. In specific examples, the term (halo)alkyl refers to alkyl substituted by at least one halogen atom. Examples of these embodiments include fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl.

“Cycloalkyl” refers to monocyclic, non-aromatic hydrocarbon groups having from 3 to 7 carbon atoms. Examples of cycloalkyl groups include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like.

The term “cyclic group” includes fully saturated, partially unsaturated and aromatic carbocyclic or heterocyclic rings, including aromatic (“aryl” or “heteroaryl”) or nonaromatic cyclic groups, for example, 5 to 7 membered monocyclic ring systems, which may have at least one heteroatom in at least one carbon atom-containing ring. A heterocyclic group containing a heteroatom may have 1, 2, or 3 heteroatoms selected from nitrogen atoms, oxygen atoms and/or sulfur atoms, where the nitrogen and sulfur heteroatoms may optionally be oxidized and the nitrogen heteroatoms may optionally be quaternized. The heterocyclic group may be attached at any heteroatom or carbon atom of the ring or ring system. In some embodiments, one or more carbon atoms of the heterocyclic ring are oxidized to form a carbonyl group. The cyclic group may be unsubstituted or carry one or more substituents, e.g. halogen, C1-6(halo)alkyl, C1-6(halo)alkoxy, OH, etc.

The term “alkoxy” includes a straight chain or branched alkyl group with a terminal oxygen linking the alkyl group to the rest of the molecule. In some embodiments, an alkoxy group is a C1-C6 alkoxy group. In some embodiments, an alkoxy group is a C1-C4alkoxy group. Alkoxy includes methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, pentoxy and so on. In specific embodiments, the term alkoxy, employed alone or in combination with other terms, refers to a group of formula —O-alkyl. Example alkoxy groups in these embodiments include methoxy, ethoxy, propoxy (e.g. n-propoxy and isopropoxy), t-butoxy, hexyloxy and the like. The term (halo)alkoxy refers to alkoxy substituted by at least one halogen atom. Examples of (halo)alkoxy groups include fluoromethoxy, difluoromethoxy, and trifluoromethoxy.

The term “heterocycle” represents” a mono- or bi-cyclic hydrocarbon ring structure optionally containing heteroatoms selected from O, S, and N. Heterocyclyl rings can have 2 to 10 carbon atoms in the ring.

The term “halogen” represents chlorine, fluorine, bromine, or iodine. The term “halo” represents chloro, fluoro, bromo, or iodo. In specific embodiments, halo refers to fluorine, chlorine, bromine and iodine, particularly to fluorine, chlorine and bromine, more particularly to fluorine and chlorine.

“Benzyl” and —CH2-phenyl are used interchangeably.

“GluN2B receptors” refers to NMDA receptors containing the GluN2B or NR2B subunit.

“Pharmaceutically acceptable” means approved or approvable by a regulatory agency of the Federal or a state government or the corresponding agency in countries other than the United States, or that is listed in the U.S. Pharmacopoeia or other generally recognized pharmacopoeia for use in animals, and more particularly, in humans. In specific embodiments, “pharmaceutically acceptable” refers to those compounds, materials, compositions, and/or dosage forms which 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.

The compounds of Formula (I) may form salts which are also within the scope of this invention. Reference to a compound of the Formula (I) herein is understood to include reference to salts thereof, unless otherwise indicated. In various embodiments, the term “salt(s)”, as employed herein, denotes acidic and/or basic salts formed with inorganic and/or organic acids and bases. Zwitterions (internal or inner salts) are included within the term “salt(s)” as used herein (and may be formed, for example, where the R substituents comprise an acid moiety such as a carboxyl group). Also included herein are quaternary ammonium salts such as alkylammonium salts. Salts of the compounds of the Formula (I) may be formed, for example, by reacting a compound I with an amount of acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilisation.

Exemplary basic salts (formed, for example, where the R substituents comprise an acidic moiety such as a carboxyl group) include ammonium salts, alkali metal salts such as sodium, lithium, and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases (for example, organic amines) such as benzathines, dicyclohexylamines, hydrabamines, N-methyl-D-glucamines, N-methyl-D-glucamides, t-butyl amines, and salts with amino acids such as arginine, lysine and the like. The basic nitrogen-containing groups may be quaternized with agents such as lower alkyl halides (e.g., methyl, ethyl, propyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g. dimethyl, diethyl, dibutyl, and diamyl sulfates), long chain halides (e.g. decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides), aralkyl halides (e.g. benzyl and phenethyl bromides), and others.

“Pharmaceutically acceptable vehicle” refers to a diluent, adjuvant, excipient or carrier with which a compound of the invention is administered. A “pharmaceutically acceptable excipient” refers to a substance that is non-toxic, biologically tolerable, and otherwise biologically suitable for administration to a subject, such as an inert substance, added to a pharmacological composition or otherwise used as a vehicle, carrier, or diluent to facilitate administration of an agent and that is compatible therewith. Examples of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils, and polyethylene glycols.

“Subject” includes humans. The terms “human,” “patient,” and “subject” are used interchangeably herein.

“Treating” or “treatment” of any disease or disorder refers, in one embodiment, to ameliorating the disease or disorder (i.e., arresting or reducing the development of the disease or at least one of the clinical symptoms thereof). In another embodiment “treating” or “treatment” refers to ameliorating at least one physical parameter, which may not be discernible by the subject. In yet another embodiment, “treating” or “treatment” refers to modulating the disease or disorder, either physically, (e.g., stabilization of a discernible symptom), physiologically, (e.g., stabilization of a physical parameter), or both. In yet another embodiment, “treating” or “treatment” refers to delaying the onset of the disease or disorder.

In treatment methods according to the invention, a therapeutically effective amount of a pharmaceutical agent according to the invention is administered to a subject suffering from or diagnosed as having such a disease, disorder, or condition. A “therapeutically effective amount” means an amount or dose sufficient to generally bring about the desired therapeutic or prophylactic benefit in patients in need of such treatment for the designated disease, disorder, or condition. Effective amounts or doses of the compounds of the present invention may be ascertained by routine methods such as modeling, dose escalation studies or clinical trials, and by taking into consideration routine factors, e.g., the mode or route of administration or drug delivery, the pharmacokinetics of the compound, the severity and course of the disease, disorder, or condition, the subjects previous or ongoing therapy, the subject's health status and response to drugs, and the judgment of the treating physician. An example of a dose is in the range of from about 0.001 to about 200 mg of compound per kg of subject's body weight per day, preferably about 0.05 to 100 mg/kg/day, or about 1 to 35 mg/kg/day, in single or divided dosage units (e.g., BID, TID, QID). For a 70-kg human, an illustrative range for a suitable dosage amount is from about 0.05 to about 7 g/day, or about 0.2 to about 2.5 g/day.

“Compounds of the present invention,” “compounds of the invention” and equivalent expressions, are meant to embrace compounds of the Formula (I) as described herein, which expression includes the pharmaceutically acceptable salts, the solvates, e.g., hydrates, where the context so permits, or the N-oxides thereof. Similarly, reference to intermediates, whether or not they themselves are claimed, is meant to embrace their salts, solvates, and N-oxides, where the context so permits.

Furthermore, in the case of the compounds of the invention which contain an asymmetric carbon atom, the invention relates to the D form, the L form and D, L mixtures and also, where more than one asymmetric carbon atom is present, to the diastereomeric forms. Those compounds of the invention which contain asymmetric carbon atoms, and which as a rule accrue as racemates, can be separated into the optically active isomers in a known manner, for example using an optically active acid. However, it is also possible to use an optically active starting substance from the outset, with a corresponding optically active or diastereomeric compound then being obtained as the end product.

Also included are solvates and hydrates of the compounds of Formula (I) and solvates and hydrates of their pharmaceutically acceptable salts.

The term “compound” as used herein is meant to include all stereoisomers, geometric isomers, tautomers, and isotopes of the structures depicted, unless otherwise indicated.

As used herein, the term “isotopic variant” refers to a compound that contains unnatural proportions of isotopes at one or more of the atoms that constitute such compound. For example, an “isotopic variant” of a compound can be radiolabeled, that is, contain one or more non-radioactive or radioactive isotopes, such as for example, deuterium (2H or D), carbon-13 (13C), nitrogen-15 (15N), or the like. It will be understood that, in a compound where such isotopic substitution is made, the following atoms, where present, may vary, so that for example, any hydrogen may be2H/D, any carbon may be13C, or any nitrogen may be15N, and that the presence and placement of such atoms may be determined within the skill of the art. Likewise, the invention may include the preparation of isotopic variants with radioisotopes, in the instance for example, where the resulting compounds may be used for drug and/or substrate tissue distribution studies. Radiolabeled compounds of the invention can be used in diagnostic methods such as single-photon emission computed tomography (SPECT). The radioactive isotopes tritium, i.e.3H, and carbon-14, i.e.14C, are particularly useful for their ease of incorporation and ready means of detection. Further, compounds may be prepared that are substituted with positron emitting isotopes, such as11C,18F,15O and13N, and would be useful in positron emission topography (PET) studies for examining substrate receptor occupancy.

All isotopic variants of the compounds of the invention, radioactive or not, are intended to be encompassed within the scope of the invention. In one aspect, provided herein are deuterated or tritiated analogs of compounds of Formula I.

Tautomeric forms may be relevant to the attainment of the optimal chemical reactivity and biological activity of a compound of interest.

Compounds of the invention may also exist as “rotamers,” that is, conformational isomers that occur when the rotation leading to different conformations is hindered, resulting in a rotational energy barrier to be overcome to convert from one conformational isomer to another.

The compounds of this invention may possess one or more asymmetric centers; such compounds can therefore be produced as individual (R)- or (S)-stereoisomers or as mixtures thereof.

Unless indicated otherwise, the description or naming of a particular compound in the specification and claims is intended to include both individual enantiomers and mixtures, racemic or otherwise, thereof. The methods for the determination of stereochemistry and the separation of stereoisomers are well-known in the art.

In some embodiments, the compound can be provided as a prodrug. The term “prodrug”, as employed herein, denotes a compound which, upon administration to a subject, undergoes chemical conversion by metabolic or chemical processes to yield a compound of the Formula (I), or a salt and/or solvate thereof.

As used herein, the phrase “optionally substituted” means unsubstituted or substituted. As used herein, the term “substituted” means that a hydrogen atom is removed and replaced by a substituent. It is understood that substitution at a given atom is limited by valency.

The compounds according to the invention have been found to have pharmacologically important properties which can be used therapeutically. The compounds of the invention can be used alone, in combination with each other or in combination with other active compounds. Compounds of Formula (I) may be inhibitors of NMDA (N-methyl-D-aspartate)-receptors, more particularly subtype specific inhibitors of NMDA NR2B receptors. It is therefore a part of the subject-matter of this invention that the compounds of the invention and their salts and also pharmaceutical preparations which comprise these compounds or their salts, can be used for treating or preventing disorders associated with, accompanied by and/or covered by NR2B receptor hyperactivity and/or disorders in which inhibiting NR2B receptors is of value.

In various embodiments, the compounds of the invention are inhibitors of the NR2B receptor with IC50values <10 μM, preferably ≤1 μM and more preferably ≤100 nM.

Exemplary Methods of Treatment

The compounds of the invention including their salts, solvates and hydrates, can be used for the treatment of central nervous system disorders of mammals including a human.

More particularly, the invention relates to the treatment of neurologic and psychiatric disorders including, but not limited to: (1) mood disorders and mood affective disorders; (2) neurotic, stress-related and somatoform disorders including anxiety disorders; (3) disorders of psychological development; (4) behavioral syndromes associated with physiological disturbances and physical factors; (5) extrapyramidal and movement disorders; (6) episodic and paroxysmal disorders, epilepsy; (7) pain; (8) forms of neurodegeneration; (9) cerebrovascular diseases, acute and chronic; and any sequelae of cerebrovascular diseases.

Examples of mood disorders and mood affective disorders that can be treated according to the present invention include, but are not limited to, bipolar disorder I depressed, hypomanic, manic and mixed form; bipolar disorder II; depressive disorders, such as single depressive episode or recurrent major depressive disorder, minor depressive disorder, depressive disorder with postpartum onset, depressive disorders with psychotic symptoms; persistent mood disorders, such as cyclothymia, dysthymia, euthymia; and premenstrual dysphoric disorder.

Examples of disorders belonging to the neurotic, stress-related and somatoform disorders that can be treated according to the present invention include, but are not limited to, anxiety disorders, general anxiety disorder, panic disorder with or without agoraphobia, specific phobia, social phobia, chronic anxiety disorders; obsessive compulsive disorder; reaction to sever stress and adjustment disorders, such as post traumatic stress disorder (PTSD); other neurotic disorders such as depersonalization-derealization syndrome.

Examples of disorders of psychological development that can be treated according to the present invention include, but are not limited to pervasive developmental disorders, including but not limited to Asperger's syndrome and Rett's syndrome, autistic disorders, childhood autism and overactive disorder associated with mental retardation and stereotyped movements, specific developmental disorder of motor function, specific developmental disorders of scholastic skills.

Examples of behavioral syndromes associated with physiological disturbances and physical factors according to the present invention include, but are not limited to mental and behavioural disorders associated with the puerperium, including but not limited to postnatal and postpartum depression; eating disorders, including but not limited to anorexia nervosa and bulimia nervosa.

Examples of extrapyramidal and movement disorders that can be treated according to the present invention include, but are not limited to Parkinson's disease; second Parkinsonism, such as postencephalitic Parkinsonism; Parkinsonism comprised in other disorders; Lewis body disease; degenerative diseases of the basal ganglia; other extrapyramidal and movement disorders including but not limited to tremor, essential tremor and drug-induced tremor, myoclonus, chorea and drug-induced chorea, drug-induced tics and tics of organic origin, drug-induced acute dystonia, drug-induced tardive dyskinesia, L-dopa-induced dyskinesia; neuroleptic-induced movement disorders including but not limited to neuroleptic malignant syndrome (NMS), neuroleptic induced parkinsonism, neuroleptic-induced early onset or acute dyskinesia, neuroleptic-induced acute dystonia, neuroleptic-induced acute akathisia, neuroleptic-induced tardive dyskinesia, neuroleptic-induced tremor; restless leg syndrome, Stiff-man syndrome.

Further examples of movement disorders with malfunction and/or degeneration of basal ganglia that can be treated according to the present invention include, but are not limited to dystonia including but not limited to focal dystonia, multiple-focal or segmental dystonia, torsion dystonia, hemispheric, generalised and tardive dystonia (induced by psychopharmacological drugs). Focal dystonia include cervical dystonia (torticolli), blepharospasm (cramp of the eyelid), appendicular dystonia (cramp in the extremities, like the writer's cramp), oromandibular dystonia and spasmodic dysphonia (cramp of the vocal cord);

Examples for episodic and paroxysmal disorders that can be treated according to the present invention include, but are not limited to epilepsy, including localization-related (focal)(partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, localization-related (focal)(partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, localization-related (focal)(partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, generalized idiopathic epilepsy and epileptic syndromes including but not limited to myoclonic epilepsy in infancy, neonatal convulsions (familial), childhood absence epilepsy (pyknolepsy), epilepsy with grand mal seizures on awakening, absence epilepsy, myoclonic epilepsy (impulsive petit mal) and nonspecific atonic, clonic, myoclonic, tonic, tonic-clonic epileptic seizures.

Further examples of epilepsy that can be treated according to the present invention include, but are not limited to epilepsy with myoclonic absences, myoclonic-astatic seizures, infantile spasms, Lennox-Gastaut syndrome, Salaam attacks, symptomatic early myoclonic encephalopathy, West's syndrome, petit and grand mal seizures; status epilepticus.

Examples of pain include, but are not limited to pain disorders related to psychological factors, such as persistent somatoform disorders; acute, chronic and chronic intractable pain, headache; acute and chronic pain related to physiological processes and physical disorders including but not limited to back pain, tooth pain, abdominal pain, low back pain, pain in joints; acute and chronic pain that is related to diseases of the musculoskeletal system and connective tissue including, but not limited to rheumatism, myalgia, neuralgia and fibromyalgia; acute and chronic pain that is related to nerve, nerve root and plexus disorders, such as trigeminal pain, postzoster neuralgia, phantom limb syndrome with pain, carpal tunnel syndrome, lesion of sciatic nerve, diabetic mononeuropathy; acute and chronic pain that is related to polyneuropathies and other disorders of the peripheral nervous system, such as hereditary and idiopathic neuropathy, inflammatory polyneuropathy, polyneuropathy induced by drugs, alcohol or toxic agents, polyneuropathy in neoplastic disease, diabetic polyneuropathy.

Examples of diseases that include forms of neurodegeneration include, but are not limited to, acute neurodegeneration, such as intracranial brain injuries, such as stroke, diffuse and local brain injuries, epidural, subdural and subarachnoid haemorrhage, and chronic neurodegeneration, such as Alzheimer's disease, Huntington's disease, and ALS.

Examples of cerebrovascular diseases include, but are not limited to, subarachnoid haemorrhage, intracerebral haemorrhage and other nontraumatic intracranial haemorrhage, cerebral infarction, stroke, occlusion and stenosis or precerebral and cerebral arteries, not resulting in cerebral infarction, dissection of cerebral arteries, cerebral aneurysm, cerebral atherosclerosis, progressive vascular leukoencephalopathy, hypertensive encephalopathy, nonpyogenic thrombosis of intracranial venous system, cerebral arteritis, cerebral amyloid angiopathy and sequelae of cerebrovascular diseases.

In some embodiments, administration of a compound of the invention, or pharmaceutically acceptable salt thereof, is effective in preventing the disease; for example, preventing a disease, condition or disorder in an individual who may be predisposed to the disease, condition or disorder but does not yet experience or display the pathology or symptomatology of the disease.

Exemplary Pharmaceutical Compositions

The present invention further provides pharmaceutical compositions comprising a therapeutically effective amount of a compound of Formula I or pharmaceutically acceptable salt, solvate, or N-oxide thereof, for use in medicine, e.g. in human or veterinary medicine. In some embodiments, the composition further comprises a pharmaceutically acceptable carrier.

An effective dose of the compounds according to the invention, or their salts, solvates or prodrugs thereof is used, in addition to physiologically acceptable carriers, diluents and/or adjuvants for producing a pharmaceutical composition. The dose of the active compounds can vary depending on the route of administration, the age and weight of the patient, the nature and severity of the diseases to be treated, and similar factors. The daily dose can be given as a single dose, which is to be administered once, or be subdivided into two or more daily doses, and is as a rule 0.001-5000 mg. Particular preference is given to administering daily doses of 0.1-3000 mg, e.g. 1-2000 mg.

Suitable administration forms are oral, parenteral, intravenous, transdermal, topical, inhalative, intranasal and sublingual preparations. Particular preference is given to using oral, parenteral, e.g. intravenous or intramuscular, intranasal preparations, e.g. dry powder or sublingual, of the compounds according to the invention. The customary galenic preparation forms, such as tablets, sugar-coated tablets, capsules, dispersible powders, granulates, aqueous solutions, alcohol-containing aqueous solutions, aqueous or oily suspensions, syrups, juices or drops, can be used.

Solid medicinal forms can comprise inert components and carrier substances, such as calcium carbonate, calcium phosphate, sodium phosphate, lactose, starch, mannitol, alginates, gelatine, guar gum, magnesium stearate, aluminium stearate, methyl cellulose, talc, highly dispersed silicic acids, silicone oil, higher molecular weight fatty acids, (such as stearic acid), gelatine, agar agar or vegetable or animal fats and oils, or solid high molecular weight polymers (such as polyethylene glycol); preparations which are suitable for oral administration can comprise additional flavourings and/or sweetening agents, if desired.

Liquid medicinal forms can be sterilized and/or, where appropriate, comprise auxiliary substances, such as preservatives, stabilizers, wetting agents, penetrating agents, emulsifiers, spreading agents, solubilizers, salts, sugars or sugar alcohols for regulating the osmotic pressure or for buffering, and/or viscosity regulators.

Examples of such additives are tartrate and citrate buffers, ethanol and sequestering agents (such as ethylenediaminetetraacetic acid and its non-toxic salts). High molecular weight polymers, such as liquid polyethylene oxides, microcrystalline celluloses, carboxymethyl celluloses, polyvinylpyrrolidones, dextrans or gelatine, are suitable for regulating the viscosity. Examples of solid carrier substances are starch, lactose, mannitol, methyl cellulose, talc, highly dispersed silicic acids, high molecular weight fatty acids (such as stearic acid), gelatine, agar agar, calcium phosphate, magnesium stearate, animal and vegetable fats, and solid high molecular weight polymers, such as polyethylene glycol.

Oily suspensions for parenteral or topical applications can be vegetable, synthetic or semisynthetic oils, such as liquid fatty acid esters having in each case from 8 to 22 C atoms in the fatty acid chains, for example palmitic acid, lauric acid, tridecanoic acid, margaric acid, stearic acid, arachidic acid, myristic acid, behenic acid, pentadecanoic acid, linoleic acid, elaidic acid, brasidic acid, erucic acid or oleic acid, which are esterified with monohydric to trihydric alcohols having from 1 to 6 C atoms, such as methanol, ethanol, propanol, butanol, pentanol or their isomers, glycol or glycerol. Examples of such fatty acid esters are commercially available miglyols, isopropyl myristate, isopropyl palmitate, isopropyl stearate, PEG 6-capric acid, caprylic/capric acid esters of saturated fatty alcohols, polyoxyethylene glycerol trioleates, ethyl oleate, waxy fatty acid esters, such as artificial ducktail gland fat, coconut fatty acid isopropyl ester, oleyl oleate, decyl oleate, ethyl lactate, dibutyl phthalate, diisopropyl adipate, polyol fatty acid esters, inter alia. Silicone oils of differing viscosity, or fatty alcohols, such as isotridecyl alcohol, 2octyldodecanol, cetylstearyl alcohol or oleyl alcohol, or fatty acids, such as oleic acid, are also suitable. It is furthermore possible to use vegetable oils, such as castor oil, almond oil, olive oil, sesame oil, cotton seed oil, groundnut oil or soybean oil.

Cellulose ethers which can dissolve or swell both in water or in organic solvents, such as hydroxypropylmethyl cellulose, methyl cellulose or ethyl cellulose, or soluble starches, can be used as film-forming agents.

Mixtures of gelatinizing agents and film-forming agents are also perfectly possible. In this case, use is made, in particular, of ionic macromolecules such as sodium carboxymethyl cellulose, polyacrylic acid, polymethacrylic acid and their salts, sodium amylopectin semiglycolate, alginic acid or propylene glycol alginate as the sodium salt, gum arabic, xanthan gum, guar gum or carrageenan. The following can be used as additional formulation aids: glycerol, paraffin of differing viscosity, triethanolamine, collagen, allantoin and novantisolic acid. Use of surfactants, emulsifiers or wetting agents, for example of Na lauryl sulphate, fatty alcohol ether sulphates, di-Na—N-lauryl-β-iminodipropionate, polyethoxylated castor oil or sorbitan monooleate, sorbitan monostearate, polysorbates (e.g. Tween), cetyl alcohol, lecithin, glycerol monostearate, polyoxyethylene stearate, alkylphenol polyglycol ethers, cetyltrimethylammonium chloride or mono/dialkylpolyglycol ether orthophosphoric acid monoethanolamine salts can also be required for the formulation. Stabilizers, such as montmorillonites or colloidal silicic acids, for stabilizing emulsions or preventing the breakdown of active substances such as antioxidants, for example tocopherols or butylhydroxyanisole, or preservatives, such as phydroxybenzoic acid esters, can likewise be used for preparing the desired formulations.

Preparations for parenteral administration can be present in separate dose unit forms, such as ampoules or vials. Use is preferably made of solutions of the active compound, preferably aqueous solution and, in particular, isotonic solutions and also suspensions. These injection forms can be made available as ready-to-use preparations or only be prepared directly before use, by mixing the active compound, for example the lyophilisate, where appropriate containing other solid carrier substances, with the desired solvent or suspending agent.

Intranasal preparations can be present as aqueous or oily solutions or as aqueous or oily suspensions. They can also be present as lyophilisates which are prepared before use using the suitable solvent or suspending agent.

Inhalable preparations can present as powders, solutions or suspensions. Preferably, inhalable preparations are in the form of powders, e.g. as a mixture of the active ingredient with a suitable formulation aid such as lactose.

The preparations are produced, aliquoted and sealed under the customary antimicrobial and aseptic conditions.

As indicated above, the compounds of the invention may be administered as a combination therapy with further active agents, e.g. therapeutically active compounds useful in the treatment of central nervous system disorders. Exemplary compounds useful in the present invention include, but are not limited to:tricyclic antidepressants, e.g. Imipramine, Desipramine, Clomipramine, Amitriptyline;tetracyclic antidepressants, e.g. Mianserin;serotonin/noradrenaline reuptake inhibitors (SNRI), e.g. Venlafaxine;selective serotonin reuptake inhibitors (SSRI), e.g. Citalopram, Fluoxetine, Paroxetine;selective noradrenaline reuptake inhibitors, e.g. Reboxetine;monoaminoxidase inhibitors, e.g. Tranylcypromine, Moclobemid; andother antidepressants, e.g. Oxitriptan, Agomelatine.

For a combination therapy, the active ingredients may be formulated as compositions containing several active ingredients in a single dose form and/or as kits containing individual active ingredients in separate dose forms. The active ingredients used in combination therapy may be co-administered or administered separately.

EXAMPLES

Chemical names were generated using ChemDraw Ultra 12.0 (CambridgeSoft Corp., Cambridge, Mass.) or ACD/Name Version 10.01 (Advanced Chemistry). A prefix of (R/S*) indicates that the compound(s) is/are single enantiomers; however the stereochemistry shown is arbitrary and the absolute stereochemistry has not been determined.

Abbreviations

Abbreviations and acronyms used herein include the following:

Prepared in analogy to J. Org Chem. (1989) 54:5938-5945, which is incorporated by reference herein in its entirety.

To a solution of sulfuric acid (40 mL) and trifluoroacetic acid (200 mL) 4-chloroaniline (29.3 g, 0.23 mol) were added. Then under ice-cooling a solution of sodium nitrite (20.6 g 0.3 mob) in water (200 mL) was added over 30 min at 15-18° C.

The solution was then stirred for 30 min while kept in the ice bath. A solution of sodium azide (25.42 g, 0.39 mol) in water (150 mL) was added dropwise over 30 min. Reaction mixture was stirred without cooling for 1 h, then extracted with diethyl ether.

The combined organic layers were washed with water two times. Then the combined organic layers were diluted with saturated aqueous sodium carbonate solution (500 mL) until the mixture became basic. The organic phase was separated and washed with brine, extracted again with diethyl ether. The organic layers were dried over sodium sulfate and evaporated at 40° C., minimum 50 mbar to afford the title product (34.7 g, 96 percent).

A mixture of 20 ml of thionyl chloride, 20 ml of methylene chloride and 2 g of [1-(4-chlorophenyl)triazol-4-yl]methanol were stirred over night at room temperature. The mixture was then poured into ice/water containing potassium carbonate. The organic layer was separated, dried with potassium carbonate and evaporated. The crude product was purified by flash chromatography to form 1.2 g of the title compound.

A mixture of 1 g of 4-chloromethyl-1-(4-chloro-phenyl)-1H-[1,2,3]triazole, 0.5 g of 3,5-dimethyl-1H-[1,2,4]triazole and 1 g of potassium carbonate in 20 ml of DMF were stirred for 2 days. After filtration and evaporation of the solvent the crude product was purified by flash chromatography to form 0.6 g of the title compound (M+H+289.7, melting range 153-156° C.).

The examples in Table 1 were prepared as described in Example 1, replacing 3,5-dimethyl-1H-[1,2,4]triazole with the appropriate triazole or imidazole derivative (step 4 in Table 1). The 3- and 5-triazolyl isomers were separated by flash chromatography (methylene chloride with 5% methanol)

The examples in Table 2 were prepared as described in example 1 replacing 4-chloroaniline with 3,4-dichloroaniline (step 1) and 3,5-dimethyl-1H-[1,2,4]triazole with the appropriate triazole or imidazole derivative (step 4). The 3- and 5-triazolyl isomers were separated by flash chromatography (methylene chloride with 5% methanol)

The examples in Table 3 were prepared as described in example 1 replacing 4-chloroaniline with appropriate aniline derivative (step 1) and replacing 3,5-dimethyl-1H-[1,2,4]triazole with the appropriate triazole or imidazole derivative (step 4). The 3- and 5-triazolyl isomers were separated by flash chromatography (methylene chloride with 5% methanol)

A solution of 2-fluoro-5-nitrobenzaldehyde (3.0 g, 17 mmol) in DCM (50 mL) was added DAST (3.42 g, 21 mmol) and stirred at RT for 18 h under nitrogen atmosphere. The reaction mass was quenched in ice-water and extracted with DCM. The organic layer was dried and concentrated to afford 2.5 g of desired product.

A solution of 2-(difluoromethyl)-1-fluoro-4-nitrobenzene (1.2 g, 6.2 mmol) in methanol (20 mL) was added iron powder (4.8 g, 24.8 mmol) followed by cone. HCl (5 mL) drop-wise. The reaction mass was stirred at RT for 1-2 h. The reaction mass was quenched in ice-water, basified with NaHCO3and extracted with DCM. The organic layer was dried and concentrated to afford 0.8 g of desired product.

To a solution of sulfuric acid (4 mL) and trifluoroacetic acid (20 mL) 3-difluoromethyl-4-fluoro-aniline (3.7 g, 0.023 mol: step 2) were added. Then under ice-cooling a solution of sodium nitrite (2.06 g 0.03 mol) in water (20 mL) was added over 30 main at 15° C.

The solution was then stirred for 30 min while kept in the ice bath. A solution of sodium azide (2.54 g, 0.039 mol) in water (20 mL) was added dropwise over 20 min, Reaction mixture was stirred without cooling for 2 h, then extracted with diethyl ether.

The combined organic layers were washed with water two times. Then the combined organic layers were diluted with saturated aqueous sodium carbonate solution (100 mL) until the mixture became basic. The organic phase was separated and washed with brine, extracted again with diethyl ether.

The organic layers were dried over sodium sulfate and evaporated at 40° C., minimum 50 mbar to afford the title product.

1-Azido-3-difluoromethyl-4-fluoro benzene (11.5 g, 61.7 mmol; step 3) and propargyl alcohol (4.15 g, 74.0 mmol) were dissolved in tert-butanol (90 mL) and water (90 mL). Copper(II)sulphate pentahydrate (1.54 g, 6.17 mmol) and L-ascorbic acid sodium salt (1.22 g, 6.17 mmol) were added and the mixture was stirred at room temperature. After 2 hours the mixture was poured into water (700 mL) and the formed precipitate was collected by filtration.

A mixture of 20 ml of thionyl chloride, 20 ml of methylene chloride and 2 g of [1-(3-difluoromethyl-4-fluoro)-1-[1,2,3]-triazol-4-yl]methanol (step 4) were stirred over night at room temperature. The mixture was then poured into ice/water containing potassium carbonate. The organic layer was separated, dried with potassium carbonate and evaporated. The crude product was purified by flash chromatography to form 1.1 g of the title compound.

A mixture of 1 g of 4-chloromethyl-1-(3-difluoromethyl-4-fluoro-phenyl)-1H-[1,2,3]triazole 0.5 g of 3,5-dimethyl-1H-[1,2,4]triazole and 1 g of potassium carbonate in 20 ml of DMF were stirred for 2 days. After filtration and evaporation of the solvent the crude product was purified by flash chromatography to form 0.5 g of the title compound (M+H+308.3, melting range 122-123° C.).

The examples in Table 4 were prepared as described in example 81 replacing 2-methyl-imidazole with the appropriate imidazole derivative (step 6).

The examples in Table 5 were prepared as described in example 81 replacing 2-fluoro-5-nitrobenzaldehyde with 2-chloro-5-nitrobenzaldehyde (step 1) aid 2-methyl-imidazole with the appropriate imidazole derivative (step 6).

The examples in Table 6 were prepared as described in example 1 replacing 4-chloroaniline with 4-chloro-3-difluoromethoxy-aniline (step 1) and 3,5-dimethyl-1H-[1,2,4]triazole with the appropriate imidazole derivative (step 4).

The heterogeneous mixture was allowed to cool to room temperature, and 12N HCl (8 ml; 96 mmol), and water (12 ml) were successively added, and this mixture was stirred at room temperature for 1 h. The resulting mixture was cooled to 0° C., and aqueous 1 N NaOH (100 nil) was then added portion wise. Et2O (250 ml), and water (200 ml) were then added, and the yellow organic layer was further washed with water (150 ml), dried over anhydrous MgSO4, filtered, and concentrated to dryness under reduced pressure.

The crude material was purified by FC (DCM/heptane=1/1 to give 4.1 g of 2-difluoromethoxy-1-fluoro-4-nitro-benzene.

Step 2 to Step 6

The synthesis was performed as described in example 81 replacing 2-difluoromethyl-1-fluoro-4-nitro-benzene with 2-difluoromethoxy-1-fluoro 4-nitro-benzene. MS[M+H]+=324.4; m.p. 159° C.

The synthesis was performed as described in example 100 replacing 2-methyl-1H-imidazole with 2-(1H-imidazol-2-yl)-ethanol (step 6). MS[M+H]+=354.4; m.p. 118° C.

The synthesis was performed as described in example 81 replacing 2-fluoro-5-nitrobenzaldehyde with 3-fluoro-5-nitrobenzaldehyde (step 1). MS[M+H]+=308.3: m.p. 141° C.

The synthesis was performed as described in example 102 replacing 2-methyl-1H-imidazole with 2-(1H-imidazol-2-yl)-ethanol (step 6). MS[M++H]+=338.3; melting range: 126-132° C.

The reaction mass was quenched in ice-water and extracted with DCM. The organic layer was dried and concentrated to dryness under reduced pressure. The crude product was purified by flash chromatography. MS[M+H]+=339.3; melting range: 111-112° C.

The compound was prepared as described in example 81 replacing 2-fluoro-5-nitrobenzaldehyde with 2-fluoro-5-nitroacetophenone (step 1). MS[M+H]=+322.3; m.p.: 149° C.

The compound was prepared as described in example 1 replacing 4-chloroaniline with 3-chloro-4-fluoroaniline (step 1).

A mixture of 2 mmol of 1-(3-chloro-4-fluoro-phenyl)-4-chloromethyl-1H-[1,2,3]triazole (step 3), 4 mmol of 1-methyl-1H-pyrazole-5-boronic acid pinacol ester, 0.5 mmol of tetrabutyl ammonium bromide, 50 mg of tetrakis(triphenylphosphine)palladium(0), 5 mmol of sodium carbonate, 50 ml of toluene and 0.5 ml of water were refluxed under nitrogen for 3 hours.

After cooling to room temperature the solvent was concentrated to dryness under reduced pressure. The crude product was purified by flash chromatography. MS[M+H]+=292.7; melting range: 85-89° C.

Example 110 was prepared as described in example 93 (table 6) replacing 2-methyl-1H-imidazole with 2-amino-1H-imidazole (step 4, reaction time 5 days). The crude free basic product was purified by flash chromatography (methylene chloride; 0 to 20% methanol).

The hydrochloride was prepared from the purified base with ethanolic hydrochloric acid. MS[M+H]+=378.2; melting range: 214-220° C.

The examples in Table 7, specifically examples 111, 113A, 113B, and 114, were prepared as described in example 110 replacing 4-chloro-3-difluoromethoxy-aniline with the appropriate aniline derivative (step 1). Example 112 may be prepared as described in example 110 by replacing 4-chloro-3-difluoromethoxy-aniline with the appropriate aniline derivative (step 1).

The compound was prepared as described in example 109 replacing 4-chloroaniline with 3-difluoro-4-fluoro-aniline in step 1 and 1-methyl-1H-pyrazole-5-boronic acid pinacol ester with 1-THP protected 1H-pyrazole-3-boronic acid pinacol ester in step 4. MS[M+H]+=294.2; melting range: 102-105° C.

Example 116 was prepared as described in example 1 replacing 3,5-dimethyl-1H-[1,2,4]triazole with (1H-imidazol-2-yl)(p-tolyl)methanone (step 4).

Example 117 was prepared as described in example 1 replacing 4-chloroaniline with 3,4-dichloroaniline (step 1) and 3,5-dimethyl-1H-[1,2,4]triazole with 2-methylbenzimidazole (step 4).

Example 118 was prepared was prepared as described in example 1 replacing 4-chloroaniline with 4-pentafluorosulfonylaniline (step 1) and 3,5-dimethyl-1H-[1,2,4]triazole with 2-(1H-imidazol-2-yl)ethanol (step 4).

Biological Assays

Inhibition of Specific Binding to the Rat NR1/NR2B Receptor

Male Wistar rats (180 to 200 g) were killed by suffocation in a CO2chamber for two minutes. Whole brains without cerebellum were removed and dissected on ice, placed into closed vials and stored at −70° C.

Membrane fractions were prepared and tested using standard techniques. At the time of the assay, 1 g of the brains was placed into 25 ml of 50 mM Tris/10 mM EDTA buffer, pH 7.1, (25 vol. per g of original tissue) and homogenized for 30 sec at 20000 rpm with an Ultraturrax T25 (Jahnke & Kunkel, IKA-Labortechnik, Staufen, Germany). The homogenate was centrifuged at 4° C. for 10 min at 48000 g (OPTIMA L-70, Beckman, Palo Alto, Calif. 94304, USA).

The supernatant was discarded and the pellet was homogenized on ice for 30 sec at 20000 rpm with an Ultraturrax and again centrifuged at 48000 g for 30 minutes at 4° C. The resulted pellet was resuspended in 25 ml of 50 mM Tris/10 mM EDTA buffer, homogenized for 30 sec with an Ultraturrax, aliquoted, frozen at −70° C. and stored until use.

After thawing on the day of the assay, a 5 ml membrane aliquot was centrifuged at 48000 g for 30 min at 4° C. The pellet was resuspended in 5 ml of 5 mM Tris/1 mM EDTA buffer, pH 7.4, homogenized for 30 sec at 20000 rpm with an Ultraturrax and centrifuged at 48000 g for 30 min at 4° C. This was repeated twice. The final pellet was homogenized in 5 ml of 5 mM Tris/l mM EDTA buffer at 4° C. with an Ultraturrax and used for the Ifenprodil-binding assay as described in the following.

The incubation was terminated by filtration of the membrane preparations using Filtermat B (Pharmacia, Uppsala Sweden) and a Micro Cell Harvester (Skatron, Lier, Norway). The Filtermat B had been presoaked with 1% polyethylene imine and carefully washed with 50 mM Tris/HCl-buffer pH 7.7 after the filtration to separate free and bound radioactivity. The filters were counted in a scintillation counter (Betaplate 1205, Berthold, Wildbad, Germany) in order to determine the specific binding of [3H]-Ifenprodil.

The optimal amount of membrane preparation in the assay had been determined and optimized for each membrane preparation separately before the test.

Test compounds were either screened at 6 to 10 increasing concentrations for the determination of IC50and Ki or at 2-4 concentrations for the determination of the percent inhibition. For pipetting of the incubation mixture we routinely used the robot Biomek2000 (Fa. Beckman).

For determination of IC50values the Hill-plot, 2-parameter-model was used. In the NR1/NR2B binding assay a dissociation constant (KD) of [3H]-Ifenprodil of 9 nM was determined.

NR2B binding assayIC50% INH% INHExample[nM]@ 1 μM@ 10 μM1NT12.431.52NT23.9433NT18.34.54NT21.62.05NT1.230.16NT11.821.67NT2.340.98143008.338.79NT6.617.910NT−6.03.511NT8.741.512NT−0.6611.013NT7.516.21412500NT49.615NT6.422.216NT3.632.617NT19.912.51846.6NTNT19NT8.214.520NT2715.321NT−1.66.822NT14.5−2.22377.4NTNT2438.4NTNT2525.8NTNT26993028.751.42738.9NTNT28573NTNT2995.8NTNT30720012.753.231NT3.72.2324.92NTNT334.65NTNT347.67NTNT357.40NTNT3617.9NTNT376.84NTNT38526NTNT397.58NTNT4017.2NTNT4126.2NTNT425.02NTNT439.84NTNT4428.3NTNT457.68NTNT46NT9.37.447NT33.8−8.448NT29.6−17.149778NTNT5021.2NTNT517.01NTNT521180NTNT5326.5NTNT545.32NTNT551.64NTNT5611.9NTNT577.21NTNT5817.4NTNT5946.0NTNT601620NTNT6131.7NTNT623320NTNT6387.1NTNT6415.1NTNT6512.4NTNT6638.0NTNT6734.5NTNT6891.6NTNT69173NTNT701.84NTNT714.47NTNT7211.4NTNT7332.7NTNT746.90NTNT7513.5NTNT7615.9NTNT77615NTNT7841.1NTNT791400NTNT802680NTNT813.83NTNT8216.2NTNT834.11NTNT8411.0NTNT853.40NTNT864.29NTNT87131NTNT8814.5NTNT893.37NTNT9015.4NTNT912.43NTNT925.24NTNT931.20NTNT943.91NTNT9572.9NTNT961.60NTNT973.12NTNT982.26NTNT996.02NTNT1001.90NTNT1014.26NTNT10225.9NTNT103136NTNT104186NTNT1054.05NTNT1068.08NTNT1094320NTNT1100.52NTNT1112.13NTNT113A0.65NTNT113B0.48NTNT1140.51NTNT115236NTNT116NT−4.9NT117141NTNT118263NTNT
HNR2BC: Effects of Test Articles on Cloned Human NR1/NR2B Ion Channels Expressed in Mammalian Cells

The ability of test compounds to act as an antagonist of NR1/NR2B were evaluated with a calcium influx assay (Calcium 5 Assay Kit, Molecular Devices).

For the antagonist assessment, NR1/NR2B was activated with the positive control agonist (Mg2+-free HBPS+100 μM glutamic acid+100 μM glycine). The effect of each test article to inhibit the signal was examined after agonist stimulation and compared to the positive control antagonist (MK-801). The signal elicited in the presence of the positive agonist (Mg2+-free HBPS+100 μM glutamic acid+100 μM glycine) was set to 100 (0% inhibition) and the signal from the positive antagonist (Mg2+-free HBPS+100 μM glutamic acid+100 μM glycine+100 μM MK-801) was set to 0 (100% inhibition).

A HEK cell line, stable transfected with hNR1/NR2B was used. This tetracycline inducible cell line is transfected with GRIN1 (GeneBank accession number NM 007327.2) and GRIN2B (GeneBank accession number NM_000834.3.). The cells were cultured in cell culture flasks with DMEM/F12 supplemented with 10% FCS, 1% PenStrep and a selection of additional antibiotics.

Forty-Eight (48) hours before the assay the cells were plated into 96-well black well, flat clear bottom microtiter plates at a density of 50000 cells/well. Twenty-Four (24) hours later the receptor expression was induced by the addition of 1 μg/ml tetracycline in the presence of 2 mM ketamine and 200 μM 7-CKA. After 24 h of receptor induction the plates were used for the assay.

The medium was removed and the cells were loaded with 200 μl loading buffer (Molecular Devices) in Mg2+-free HBPS containing 100 μM 7-CKA at 37° C. for one (1) hour.

The test compounds were then solubilized in 100% DMSO and diluted to yield eight (8) different concentrations in 100% DMSO. A 96 well drug plate was prepared by diluting with water and glycine/glutamate to a 5-fold of final test concentration. Fluorescence intensity of the cells in the plate was measured in a FlexStation using an excitation wavelength of 485 nm and an emission wavelength of 525 nm. Twenty (20) seconds after starting the recordings the compounds together with the agonists glycine (100 μM) and glutamate (100 μM) were added into the wells and the fluorescence measured for ninety (90) seconds in summary.

The IC50 values provided in the paragraph below were determined using a 3 parameter plot.

ExampleIC50 [μM]2317.5423.17813.79824.89844.2930.41970.581011.651091091100.0771113.42113A0.84113B0.661142.3411510.511622.35
Inhibition of Specific Binding to the hERG-Receptor (HERGBD)

A HEK cell line with stable transfected human ERG receptor was used for the assay. The cells were grown adherently and maintained in DULBECCOS' MEM medium with 10% FBS, 1% non-essential amino acids, 1% Penicillin/Streptomycin and 400 μg/ml G418 (Calbiochem).

Cells were split 2-3 times weekly between 1:3 and 1:4. For binding assays and membrane preparations the cell culture medium was removed, cells were washed with PBS. Crude membranes for radioligand binding experiments were prepared by scraping the cells off the dishes in ice cold 20 mM HEPES/0.1 mM KCl/pH 7.2. The cell suspension was homogenized on ice (Ultra turrax, 3×20 sec.) and the homogenate was spun for 10 min (1° C., 1000 g, OPTIMA, SW28, 2800 U/min). The supernatant was than centrifuged for 40 min at 100000 g (1° C., OPTIMA, SW28, 23000 U/min). The membrane pellet was resuspended in 20 mM HEPES/0.1 mM KCl/pH 7.2, frozen and stored at −80° C.

After thawing on the day of the assay, the membrane suspension was diluted further with 20 mM HEPES/0.1 mM KCl/pH 7.2.

The incubation mixture of 200 μl contained 1.5 nmol/l 3H-Dofetilide, optimized amount of membrane preparation, 20 mM HEPES/0.1 mM KCl/(pH 7.2) and inhibitor in 1% DMSO. Nonspecific binding was estimated in the presence of 10 M Dofetilide. The samples were incubated for 90 min. at RT.

Binding was terminated by filtration of the incubated membrane preparations using Filtermat B (Pharmacia, Uppsala Sweden) and a Micro Cell Harvester (Skatron, Lier, Norway). The Filtermat B had been presoaked with 1% polyethylenimine and carefully washed with 0.05 M Tris/HCl-buffer pH=7.7 after the filtration to separate free and bound radioactivity. The filters were counted in a scintillation counter (Betaplate 1205, Berthold, Wildbad, Germany) in order to determine the specific binding of [3H]-Dofetilide.

The optimal amount of membrane preparation in the assay was determined and optimized for each membrane preparation separately in front of using the membranes in compound testing.

Test compounds were either screened at 6 to 10 increasing concentrations for the determination of IC50 and Ki or at 2-4 concentrations for the determination of the percent inhibition. For pipetting of the incubation mixture we routinely use the robot Biomek2000 (Fa. Beckman).

The IC50 values in the table below were determined using the Hill-plot, 2-parameter-model.

Male Wistar rats (180 to 200 g) were killed by suffocation in a CO2chamber for two minutes. Whole brains without cerebellum were removed and dissected on ice, placed into closed vials and stored at −70° C.

Membrane fractions were prepared and tested using standard techniques. At the time of the assay, 1 g of the brains were placed into 25 ml of 50 mM Tris/10 mM EDTA buffer, pH=7.1, (25 vol. per g of original tissue) and was homogenized for 30 sec at 20000 U/min with an Ultraturrax T25 (Jahnke & Kunkel, IKA-Labortechnik, Staufen, Germany). The homogenate was centrifuged at 4° C. for 10 min at 48000 g (OPTIMA L-70, Beckman, Palo Alto, Calif. 94304, USA). The supernatant was discarded and the pellet was homogenized on ice for 30 sec at 20000 U/min with an Ultraturrax and again centrifuged at 48000 g for 30 minutes at 4° C. The resultant pellet was resuspended in 25 ml of 50 mM Tris/10 mM EDTA buffer, homogenized for 30 sec with an Ultraturrax, aliquoted, frozen at −70° C. and stored until use

After thawing on the day of the assay, a 5 ml membrane aliquote was centrifuged at 48000 g for 30 min at 4° C. The pellet was resuspended in 5 ml of 5 mM Tris/1 mM EDTA buffer, pH=7.4, homogenized for 30 sec at 20000 U/min with an Ultraturrax and centrifuged at 48000 g for 30 min at 4° C. This step was repeated twice. The final pellet was homogenized in 5 ml of 5 mM Tris/mM EDTA buffer at 4° C. with an Ultraturrax and used for the Ifenprodil-binding assay.

Binding was terminated by filtration of the incubated membrane preparations using Filtermat B (Pharmacia, Uppsala Sweden) and a Micro Cell Harvester (Skatron, Lier, Norway). The Filtermat B had been presoaked with 1% polyethylenimine and carefully washed with 50 nM Tris/HCl-buffer pH=7.7 after the filtration to separate free and bound radioactivity. The filters were counted in a scintillation counter (Betaplate 1205, Berthold, Wildbad, Germany) in order to determine the specific binding of [3H]-Ifenprodil.

The optimal amount of membrane preparation in the assay has been determined and optimised for each membrane preparation separately in front of using the membranes in compound testing.

Test compounds were either screened at 6 to 10 increasing concentrations for the determination of IC50 and Ki or at 2-4 concentrations for the determination of the percent inhibition. For pipetting of the incubation mixture the robot Biomek2000 (Fa. Beckman) was used.

The IC50 values in the tables below were determined using the Hill-plot, 2-parameter-model. In the NR1/NR2B binding assay a dissociation constant (KD) of [3H]-Ifenprodil was determined to be 9 nM. The specific binding in this assay was about 80%.

Reference compounds and their IC50 values tested in the hERG receptor binding assay are provided below.

The compounds of the invention show significant antidepressive effects in the forced swim test in mice, an animal model of depression at doses of 100 mg/kg or below.

The method, which detects antidepressant activity, follows that described by Porsolt et al (Arch. Int. Pharmacodyn.,229, 327-336, 1977), which is incorporated by reference herein in its entirety.

Mice forced to swim in a situation from which they cannot escape rapidly become immobile. Antidepressants decrease the duration of immobility.

The mice were placed in the water for 6 minutes and the duration of immobility during the last 4 minutes was measured. The latency to the first bout of immobility was also recorded starting from the beginning of the test. 10 mice were studied per group. The test substance was administered p.o. 30 minutes before the test and compared with vehicle control group. The test was performed blind. The results are shown in the table below.

All patents, patent applications, publications and presentations referred to herein are incorporated by reference in their entirety.

While the foregoing specification teaches the principles of the present invention, and specific embodiments of the invention have been described for the purposes of illustration, and examples have been provided for the purposes of illustration, it will be understood that various modifications may be made without deviating from the spirit and scope of the invention as come within the scope of the following claims and their equivalents.