Patent Application
20090111857
The present invention is directed to novel compounds, their use in therapy and pharmaceutical compositions comprising said novel compounds.
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system (CNS). Glutamate produces its effects on central neurons by binding to and thereby activating cell surface receptors. These receptors have been divided into two major classes, the ionotropic and metabotropic glutamate receptors, based on the structural features of the receptor proteins, the means by which the receptors transduce signals into the cell, and pharmacological profiles.
The metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors that activate a variety of intracellular second messenger systems following the binding of glutamate. Activation of mGluRs in intact mammalian neurons elicits one or more of the following responses: activation of phospholipase C; increases in phosphoinositide (PI) hydrolysis; intracellular calcium release; activation of phospholipase D; activation or inhibition of adenyl cyclase; increases or decreases in the formation of cyclic adenosine monophosphate (cAMP); activation of guanylyl cyclase; increases in the formation of cyclic guanosine monophosphate (cGMP); activation of phospholipase A2; increases in arachidonic acid release; and increases or decreases in the activity of voltage- and ligand-gated ion channels. Schoepp et al, Trends Pharmacol. Sci. 14:13 (1993), Schoepp, Neurochem. Int. 24:439 (1994), Pin et al., Neuropharmacology 34:1 (1995), Bordi and Ugolini, Prog. Neurobiol. 59:55 (1999).
Molecular cloning has identified eight distinct mGluR subtypes, termed mGluR1 through mGluR8. Nakanishi, Neuron 13:1031 (1994), Pin et al., Neuropharmacology 34:1 (1995), Knopfel et al, J Med. Chem. 38:1417 (1995). Further receptor diversity occurs via expression of alternatively spliced forms of certain mGluR subtypes. Pin et al., PNAS 89:10331 (1992), Minakami et al., BBRC 199:1136 (1994), Joly et al., J Neurosci. 15:3970 (1995).
Metabotropic glutamate receptor subtypes may be subdivided into three groups, Group I, Group II, and Group III mGluRs, based on amino acid sequence homology, the second messenger systems utilized by the receptors, and by their pharmacological characteristics. Group I mGluR comprises mGluR1, mGluR5 and their alternatively spliced variants. The binding of agonists to these receptors results in the activation of phospholipase C and the subsequent mobilization of intracellular calcium.
Attempts at elucidating the physiological roles of Group I mGluRs suggest that activation of these receptors elicits neuronal excitation. Various studies have demonstrated that Group I mGluR agonists can produce postsynaptic excitation upon application to neurons in the hippocampus, cerebral cortex, cerebellum, and thalamus, as well as other CNS regions. Evidence indicates that this excitation is due to direct activation of postsynaptic mGluRs, but it also has been suggested that activation of presynaptic mGluRs occurs, resulting in increased neurotransmitter release. Baskys, Trends Pharmacol. Sci. 15:92 (1992), Schoepp, Neurochem. Int. 24:439 (1994), Pin et al., Neuropharmacology 34:1 (1995), Watkins et al., Trends Pharmacol. Sci. 15:33 (1994).
Metabotropic glutamate receptors have been implicated in a number of normal processes in the mammalian CNS. Activation of m-GluRs has been shown to be required for induction of hippocampal long-term potentiation and cerebellar long-term depression. Bashir et al., Nature 363:347 (1993), Bortolotto et al., Nature 368:740 (1994), Aiba et al. Cell 79:365 (1994), Aiba et al., Cell 79:377 (1994). A role for mGluR activation in nociception and analgesia also has been demonstrated, Meller et al., Neuroreport 4: 879 (1993), Bordi and Ugolini, Brain Res. 871:223 (1999). In addition, mGluR activation has been suggested to play a modulatory role in a variety of other normal processes including synaptic transmission, neuronal development, apoptotic neuronal death synaptic plasticity, spatial learning, olfactory memory, central control of cardiac activity, waking, motor control and control of the vestibulo-ocular reflex. Nakanishi, Neuron 13: 1031 (1994), Pin et al., Neuropharmacology 34:1, Knopfel et al., J. Med. Chem. 38:1417 (1995).
Further, Group I metabotropic glutamate receptors and mGluR5 in particular, have been suggested to play roles in a variety of pathophysiological processes and disorders affecting the CNS. These include stroke, head trauma, anoxic and ischemic injuries, hypoglycemia, epilepsy, neurodegenerative disorders such as Alzheimer's disease and pain. Schoepp et al., Trends Pharmacol. Sci. 14:13 (1993), Cunningham et al., Life Sci. 54:135 (1994), Hollman et al., Ann. Rev. Neurosci. 17:31 (1994), Pin et al., Neuropharmacology 34:1 (1995), Knopfel et at, J. Med. Chem. 38:1417 (1995), Spooren et al., Trends Pharmacol Sci. 22:331 (2001), Gasparini et al. Curr. Opin. Pharmacol 2:43 (2002), Neugebauer Pain 98:1 (2002). Much of the pathology in these conditions is thought to be due to excessive glutamate-induced excitation of CNS neurons. Because Group I mGluRs appear to increase glutamate-mediated neuronal excitation via postsynaptic mechanisms and enhanced presynaptic glutamate release, their activation probably contributes to the pathology. Accordingly, selective antagonists of Group I mGluR receptors could be therapeutically beneficial, specifically as neuroprotective agents, analgesics or anticonvulsants.
Recent advances in the elucidation of the neurophysiological roles of metabotropic glutamate receptors generally and Group I in particular, have established these receptors as promising drug targets in the therapy of acute and chronic neurological and psychiatric disorders and chronic and acute pain disorders.
The lower esophageal sphincter (LES) is prone to relaxing intermittently. As a consequence, fluid from the stomach can pass into the esophagus since the mechanical barrier is temporarily lost at such times, an event hereinafter referred to as “reflux”.
Gastro-esophageal reflux disease (GERD) is the most prevalent upper gastrointestinal tract disease. Current pharmacotherapy aims at reducing gastric acid secretion, or at neutralizing acid in the esophagus. The major mechanism behind reflux has been considered to depend on a hypotonic lower esophageal sphincter. However, e.g. Holloway & Dent (1990) Gatstroenterol Clin. N. Amer. 19, pp. 517-535, has shown that most reflux episodes occur during transient lower esophageal sphincter relaxations (TLESRs), i.e. relaxations not triggered by swallows. It has also been shown that gastric acid secretion usually is normal in patients with GERD.
The novel compounds according to the present invention are assumed to be useful for the inhibition of transient lower esophageal sphincter relaxations (TLESRs) and thus for treatment of gastro-esophageal reflux disorder (GERD).
It is well known that certain compounds may cause undesirable effects on cardiac repolarisation in man, observed as a prolongation of the QT interval on electrocardiograms (ECG). In extreme circumstances, this drug-induced prolongation of the QT interval can lead to a type of cardiac arrhythmia called Torsades de Pointes (TdP; Vandenberg et al. hERG K+ channels: friend and foe. Trends Pharmacol Sci 2001; 22: 240-246), leading ultimately to ventricular fibrillation and sudden death. The primary event in this syndrome is inhibition of the rapid component of the delayed rectifying potassium current (IKr) by these compounds. The compounds bind to the aperture-forming alpha sub-units of the channel protein carrying this current sub-units that are encoded by the human ether-a-go-go-related gene (hERG). Since IKr plays a key role in repolarisation of the cardiac action potential, its inhibition slows repolarisation and this is manifested as a prolongation of the QT interval. Whilst QT interval prolongation is not a safety concern per se, it carries a risk of cardiovascular adverse effects and in a small percentage of people it can lead to TdP and degeneration into ventricular fibrillation.
Generally, compounds of the present invention have low activity against the hERG-encoded potassium channel. In this regard, low activity against hERG in vitro is indicative of low activity in vivo.
It is also desirable for drugs to possess good metabolic stability in order to enhance drug efficacy. Stability against human microsomal metabolism in vitro is indicative of stability towards metabolism in vivo.
Because of their physiological and pathophysiological significance, there is a need for new potent mGluR agonists and antagonists that display a high selectivity for mGluR subtypes, particularly the Group I receptor subtype, most particularly the mGluR5.
The object of the present invention is to provide compounds exhibiting an activity at metabotropic glutamate receptors (mGluRs), especially at the mGluR5 receptor. In particular, the compounds according to the present invention are predominantly peripherally acting, i.e. have a limited ability of passing the blood-brain barrier.
The present invention relates to a compound of formula I:
wherein
R1 is methyl, halogen or cyano;
R2 is hydrogen or fluoro;
R3 is hydrogen, C1-C3 alkyl or cyclopropyl;
R4 is C1-C3 alkyl or cyclopropyl;
R6 is hydrogen or C1-C3 alkyl;
R7 is hydrogen or C1-C3 alkyl;
as well as pharmaceutically acceptable salts, hydrates, isoforms, tautomers and/or enantiomers thereof.
In one embodiment R1 is halogen.
In a further embodiment, R1 is chloro.
In a further embodiment, R2 is hydrogen.
In a further embodiment, R3 is methyl.
In a further embodiment, R4 is methyl.
In a further embodiment, R5 is NH2.
In a further embodiment, R5 is methoxy.
In a further embodiment, Z is phenyl.
In a further embodiment, Z is pyridinyl.
In a further embodiment, Z is connected to COR5 at the para position of Z.
In a further embodiment, Z is connected to COR5 at the meta position of Z.
In a further embodiment, Z is connected to COR5 through a carbon atom of Z.
Another embodiment is a pharmaceutical composition comprising as active ingredient a therapeutically effective amount of the compound according to formula I, in association with one or more pharmaceutically acceptable diluents, excipients and/or inert carriers.
Other embodiments, as described in more detail below, relate to a compound according to formula I for use in therapy, in treatment of mGluR5 mediated disorders, in the manufacture of a medicament for the treatment of mGluR5 mediated disorders.
Still other embodiments relate to a method of treatment of mGluR5 mediated disorders, comprising administering to a mammal a therapeutically effective amount of the compound according to formula I.
In another embodiment, there is provided a method for inhibiting activation of mGluR5 receptors, comprising treating a cell containing said receptor with an effective amount of the compound according to formula I.
The compounds of the present invention are useful in therapy, in particular for the treatment of neurological, psychiatric, pain, and gastrointestinal disorders.
It will also be understood by those of skill in the art that certain compounds of the present invention may exist in solvated, for example hydrated, as well as unsolvated forms. It will further be understood that the present invention encompasses all such solvated forms of the compounds of formula I.
Within the scope of the invention are also salts of the compounds of formula I. Generally, pharmaceutically acceptable salts of compounds of the present invention are obtained using standard procedures well known in the art, for example, by reacting a sufficiently basic compound, for example an alkyl amine with a suitable acid, for example, HCl, acetic acid or a methanesulfonic acid to afford a salt with a physiologically acceptable anion. It is also possible to make a corresponding alkali metal (such as sodium, potassium, or lithium) or an alkaline earth metal (such as a calcium) salt by treating a compound of the present invention having a suitably acidic proton, such as a carboxylic acid or a phenol, with one equivalent of an alkali metal or alkaline earth metal hydroxide or alkoxide (such as the ethoxide or methoxide), or a suitably basic organic amine (such as choline or meglumine) in an aqueous medium, followed by conventional purification techniques. Additionally, quaternary ammonium salts can be prepared by the addition of alkylating agents, for example, to neutral amines.
In one embodiment of the present invention, the compound of formula I may be converted to a pharmaceutically acceptable salt or solvate thereof, particularly, an acid addition salt such as a hydrochloride, hydrobromide, phosphate, acetate, fumarate, maleate, tartrate, citrate, methanesulphonate or p-toluenesulphonate.
The general terms used in the definition of formula I have the following meanings:
Halogen as used herein is selected from chlorine, fluorine, bromine or iodine.
C1-C3 alkyl is a straight or branched alkyl group, having from 1 to 3 carbon atoms, for example methyl, ethyl, n-propyl or isopropyl.
C1-C3 alkoxy is an alkoxy group having 1 to 3 carbon atoms, for example methoxy, ethoxy, isopropoxy or n-propoxy.
All chemical names were generated using ACDLABS 9.04.
In formula I above, X may be present in any of the two possible orientations.
The compounds of the present invention may be formulated into conventional pharmaceutical compositions comprising a compound of formula I, or a pharmaceutically acceptable salt or solvate thereof, in association with a pharmaceutically acceptable carrier or excipient. The pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include, but are not limited to, powders, tablets, dispersible granules, capsules, cachets, and suppositories.
A solid carrier can be one or more substances, which may also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders, or tablet disintegrating agents. A solid carrier can also be an encapsulating material.
In powders, the carrier is a finely divided solid, which is in a mixture with the finely divided compound of the invention, or the active component. In tablets, the active component is mixed with the carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired.
For preparing suppository compositions, a low-melting wax such as a mixture of fatty acid glycerides and cocoa butter is first melted and the active ingredient is dispersed therein by, for example, stirring. The molten homogeneous mixture is then poured into convenient sized moulds and allowed to cool and solidify.
Suitable carriers include, but are not limited to, magnesium carbonate, magnesium stearate, talc, lactose, sugar, pectin, dextrin, starch, tragacanth, methyl cellulose, sodium carboxymethyl cellulose, low-melting wax, cocoa butter, and the like.
The term composition is also intended to include the formulation of the active component with encapsulating material as a carrier providing a capsule in which the active component (with or without other carriers) is surrounded by a carrier which is thus in association with it. Similarly, cachets are included. Tablets, powders, cachets, and capsules can be used as solid dosage forms suitable for oral administration.
Liquid form compositions include solutions, suspensions, and emulsions. For example, sterile water or water propylene glycol solutions of the active compounds may be liquid preparations suitable for parenteral administration. Liquid compositions can also be formulated in solution in aqueous polyethylene glycol solution.
Aqueous solutions for oral administration can be prepared by dissolving the active component in water and adding suitable colorants, flavoring agents, stabilizers, and thickening agents as desired. Aqueous suspensions for oral use can be made by dispersing is the finely divided active component in water together with a viscous material such as natural synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose, and other suspending agents known to the pharmaceutical formulation art. Exemplary compositions intended for oral use may contain one or more coloring, sweetening, flavoring and/or preservative agents.
Depending on the mode of administration, the pharmaceutical composition will include from about 0.05% w (percent by weight) to about 99% w, or from about 0.10% w to 50% w, of a compound of the invention, all percentages by weight being based on the total weight of the composition.
A therapeutically effective amount for the practice of the present invention can be determined by one of ordinary skill in the art using known criteria including the age, weight and response of the individual patient, and interpreted within the context of the disease which is being treated or which is being prevented.
The compounds according to the present invention are useful in the treatment of conditions associated with excitatory activation of mGluR5 and for inhibiting neuronal damage caused by excitatory activation of mGluR5. The compounds may be used to produce an inhibitory effect of mGluR5 in mammals, including man.
The Group I mGluR receptors including mGluR5 are highly expressed in the central and peripheral nervous system and in other tissues. Thus, it is expected that the compounds of the invention are well suited for the treatment of mGluR5 mediated disorders such as acute and chronic neurological and psychiatric disorders, gastrointestinal disorders, and chronic and acute pain disorders.
The invention relates to compounds of formula I, as defined herein before, for use in therapy.
The invention relates to compounds of formula I, as defined herein before, for use in treatment of mGluR5 mediated disorders.
The invention relates to compounds of formula I, as defined herein before, for use in treatment of Alzheimer's disease senile dementia, AIDS-induced dementia, Parkinson's disease, amylotropic lateral sclerosis, Huntington's Chorea, migraine, epilepsy, schizophrenia, depression, anxiety, acute anxiety, opthalmological disorders such as retinopathies, diabetic retinopathies, glaucoma, auditory neuropathic disorders such as tinnitus, chemotherapy induced neuropathies, post-herpetic neuralgia and trigeminal neuralgia, tolerance, dependency, Fragile X, autism, mental retardation, schizophrenia and Down's Syndrome.
The invention relates to compounds of formula I, as defined above, for use in treatment of pain related to migraine, inflammatory pain, neuropathic pain disorders such as diabetic neuropathies, arthritis and rheumatoid diseases, low back pain, post-operative pain and pain associated with various conditions including cancer, angina, renal or billiary colic, menstruation, migraine and gout.
The invention relates to compounds of formula I as defined herein before, for use in treatment of stroke, head trauma, anoxic and ischemic injuries, hypoglycemia, cardiovascular diseases and epilepsy.
The present invention relates also to the use of a compound of formula I as defined herein before, in the manufacture of a medicament for the treatment of mGluR Group I receptor-mediated disorders and any disorder listed above.
One embodiment of the invention relates to the use of a compound according to formula I in the treatment of gastrointestinal disorders.
Another embodiment of the invention relates a compound of formula I for the inhibition of transient lower esophageal sphincter relaxations, for the treatment of GERD, for the prevention of gastroesophageal reflux, for the treatment regurgitation, for treatment of asthma, for treatment of laryngitis, for treatment of lung disease, for the management of failure to thrive, for the treatment of irritable bowel syndrome (IBS) and for the treatment of functional dyspepsia (FD).
Another embodiment of the invention relates to the use of a compound of formula I for the manufacture of a medicament for inhibition of transient lower esophageal sphincter relaxations, for the treatment of GERD, for the prevention of gastroesophageal reflux, for the treatment regurgitation, for treatment of asthma, for treatment of laryngitis, for treatment of lung disease, for the management of failure to thrive, for the treatment of irritable bowel syndrome (IBS) and for the treatment of functional dyspepsia (FD).
Another embodiment of the present invention relates to the use of a compound of formula I for treatment of overactive bladder or urinary incontinence.
The wording “TLESR”, transient lower esophageal sphincter relaxations, is herein defined in accordance with Mittal, R. K., Holloway, R. H., Penagini, R., Blackshaw, L. A., Dent, J., 1995; Transient lower esophageal sphincter relaxation. Gastroenterology 109, pp. 601-610.
The wording “reflux” is herein defined as fluid from the stomach being able to pass into the esophagus, since the mechanical barrier is temporarily lost at such times.
The wording “GERD”, gastro-esophageal reflux disease, is herein defined in accordance with van Heerwarden, M. A., Smout A. J. P. M, 2000; Diagnosis of reflux disease. Baillière's Clin. Gastroenterol 14, pp. 759-774.
The compounds of formula I above are useful for the treatment or prevention of obesity or overweight, (e.g., promotion of weight loss and maintenance of weight loss), prevention or reversal of weight gain (e.g., rebound, medication-induced or subsequent to cessation of smoking), for modulation of appetite and/or satiety, eating disorders (e.g. binge eating, anorexia, bulimia and compulsive) and cravings (for drugs, tobacco, alcohol, any appetizing macronutrients or non-essential food items).
The invention also provides a method of treatment of mGluR5-mediated disorders and any disorder listed above, in a patient suffering from, or at risk of, said condition, which comprises administering to the patient an effective amount of a compound of formula I, as herein before defined.
The dose required for the therapeutic or preventive treatment of a particular disorder will necessarily be varied depending on the host treated, the route of administration and the severity of the illness being treated.
In the context of the present specification, the term “therapy” and “treatment” includes prevention or prophylaxis, unless there are specific indications to the contrary. The terms “therapeutic,” and “therapeutically” should be construed accordingly.
In this specification, unless stated otherwise, the term “antagonist” and “inhibitor” shall mean a compound that by any means, partly or completely, blocks the transduction pathway leading to the production of a response by the ligand.
The term “disorder”, unless stated otherwise, means any condition and disease associated with metabotropic glutamate receptor activity.
One embodiment of the present invention is a combination of a compound of formula I and an acid secretion inhibiting agent. A “combination” according to the invention may be present as a “fix combination” or as a “kit of parts combination”. A “fix combination” is defined as a combination wherein the (i) at least one acid secretion inhibiting agent; and (ii) at least one compound of formula I are present in one unit. A “kit of parts combination” is defined as a combination wherein the (i) at least one acid secretion inhibiting agent; and (ii) at least one compound of formula I are present in more than one unit. The components of the “kit of parts combination” may be administered simultaneously, sequentially or separately. The molar ratio of the acid secretion inhibiting agent to the compound of formula I used according to the invention in within the range of from 1:100 to 100:1, such as from 1:50 to 50:1 or from 1:20 to 20:1 or from 1:10 to 10:1. The two drugs may be administered separately in the same ratio. Examples of acid secretion inhibiting agents are H2 blocking agents, such as cimetidille, ranitidine; as well as proton pump inhibitors such as pyridinylmethylsulfinyl benzimidazoles such as omeprazole, esomeprazole, lansoprazole, pantoprazole, rabeprazole or related substances such as leminoprazole.
In addition to their use in therapeutic medicine, the compounds of formula I, as well as salts and hydrates of such compounds, are useful as pharmacological tools in the development and standardisation of in vitro and in vivo test systems for the evaluation of the effects of inhibitors of mGluR related activity in laboratory animals such as cats, dogs, rabbits, monkeys, rats and mice, as part of the search for new therapeutic agents.
Another aspect of the present invention provides processes for preparing compounds of formula I, or salts or hydrates thereof. Processes for the preparation of the compounds in the present invention are described herein.
Throughout the following description of such processes it is to be understood that where appropriate, suitable protecting groups will be added to, and subsequently removed from, to the various reactants and intermediates in a manner that will be readily understood by one skilled in the art of organic synthesis. Conventional procedures for using such protecting groups as well as examples of suitable protecting groups are described, for example, in “Protective Groups in Organic Synthesis”, T. W. Green, P. G. M. Wuts, Wiley-Interscience, New York, (1999). It is also to be understood that a transformation of a group or substituent into another group or substituent by chemical manipulation can be conducted on any intermediate or final product on the synthetic path toward the final product, in which the possible type of transformation is limited only by inherent incompatibility of other functionalities carried by the molecule at that stage to the conditions or reagents employed in the transformation. Such inherent incompatibilities, and ways to circumvent them by carrying out appropriate transformations and synthetic steps in a suitable order, will be readily understood to the one skilled in the art of organic synthesis. Examples of transformations are given below, and it is to be understood that the described transformations are not limited only to the generic groups or substituents for which the transformations are exemplified. References and descriptions on other suitable transformations are given in “Comprehensive Organic Transformations—A Guide to Functional Group Preparations” R. C. Larock, VHC Publishers, Inc. (1989). References and descriptions of other suitable reactions are described in textbooks of organic chemistry, for example, “Advanced Organic Chemistry”, March, 4th ed. McGraw Hill (1992) or, “Organic Synthesis”, Smith, McGraw Hill, (1994). Techniques for purification of intermediates and final products include for example, straight and reversed phase chromatography on column or rotating plate, recrystallisation, distillation and liquid-liquid or solid-liquid extraction, which will be readily understood by the one skilled in the art. The definitions of substituents and groups are as in formula I except where defined differently. The term “room temperature” and “ambient temperature” shall mean, unless otherwise specified, a temperature between 16 and 25° C.
The term “reflux” shall mean, unless otherwise stated, in reference to an employed solvent a temperature at or above the boiling point of named solvent.
Boc tert-Butoxycarbonyl
DIBAL-H Diisobutylaluminium hydride
DMAP N,N-Dimethyl-4-aminopyridine
EDCI N-[3-(dimethylamino)propyl]-N′-ethylcarbodiimide hydrochloride
Et2O Diethyl ether
EtOAc Ethyl acetate
HBTU O-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate
HPLC High performance liquid chromatography
LAH Lithium aluminium hydride
LCMS HPLC mass spec
MCPBA m-Chloroperbenzoic acid
NMR Nuclear magnetic resonance
SPE Solid phase extraction (usually containing silica gel for mini-chromatography)
A compound of formula I, wherein X is a 1,2,4-oxadiazole (V) may be prepared through cyclization of a compound of formula IV, which in turn may be formed from a suitably activated compound of formula III with a compound of formula II.
Compounds of formula II may be prepared from a suitable nitrile, The compound of formula III may be activated in the following non-limiting ways: i) as the acid chloride formed from the acid using a suitable reagent such as oxalyl chloride or thionyl chloride; ii) as an anhydride or mixed anhydride formed from treatment with a reagent such as alkyl chloroformate; iii) using traditional methods to activate acids in amide coupling reactions such as EDCI with HOBt or uronium salts like HBTU; iv) as an alkyl ester when the hydroxyamidine is deprotonated using a strong base like sodium tert-butoxide or sodium hydride in a solvent such as EtOH or toluene at elevated temperatures (50° C.-110° C.).
This transformation of compounds II and III into compounds of type V may be performed as two consecutive steps via an isolated intermediate of type IV, as described above, or the cyclization of the intermediate formed in situ may occur spontaneously during the ester formation. The formation of ester IV may be accomplished using an appropriate aprotic solvent such as DCM, THF, DMF or toluene, with optionally an appropriate organic base such as triethylamine, diisopropylethylamine and the like or an inorganic base such sodium bicarbonate or potassium carbonate. The cyclization of compounds of formula IV to form an oxadiazole may be carried out on the crude ester with evaporation and replacement of the solvent with a higher boiling solvent such as DMF or with aqueous extraction to provide a semi-purified material or with material purified by standard chromatographic methods. The cyclization may be accomplished by heating conventionally or by microwave irradiation (100° C. 180° C.), in a suitable solvent such as pyridine or DMF or using a lower temperature method employing reagents like tetrabutylammonium fluoride in THF or by any other suitable known literature method.
Further examples of the above described reactions can be found in Poulain et al., Tetrahedron Lett., (2001), 42, 1495-98, Ganglott et al., Tetrahedron Lett., (2001), 42, 1441-43, and Mathvink et at, Bioorg. Med. Chem. Lett. (11999), 9, 1869-74, which are hereby included as references.
Aryl nitrites are available by a variety of methods including cyanation of an aryl halide or triflate under palladium or nickel catalysis using an appropriate cyanide source such as zinc cyanide in an appropriate solvent such as N,N-dimethylformamide. The corresponding acid is available from the nitrile by hydrolysis under either acidic or basic conditions in an appropriate solvent such as aqueous alcohols. Aryl acids are also available from a variety of other sources, including iodo- or bromo-lithium exchange followed by trapping with CO2 to give directly the acid.
Carboxylic acids may be converted to primary amides using any compatible method to activate the acid, including via the acid chloride or mixed anhydride, followed by trapping with any source of ammonia, including ammonium chloride in the presence of a suitable base, ammonium hydroxide, methanolic ammonia or ammonia in an aprotic solvent such as dioxane. This amide intermediate may be converted to the nitrile using a variety of dehydration reagents such as oxalyl chloride or thionyl chloride. This reaction sequence to convert an acid into a nitrite may also be applied to non-aromatic acids, including suitably protected amino acid derivatives. A suitable protecting group for an amine, in an amino acid or in a remote position of any other acid starting material, may be any group which removes the basicity and nucleophilicity of the amine functionality, including such carbamate protecting group as Boc.
Some acids are more easily prepared taking advantage of commercially available analogs. For example, 6-methylpyridine-4-carboxylic acid is prepared by dechlorination of 2-chloro-6-methylpyridine-4-carboxylic acid. Certain types of substituted fluoro-benzonitriles and benzoic acids are available from bromo-difluoro-benzene via displacement of one fluoro group with a suitable nucleophile such as imidazole in the presence of a base such as potassium carbonate in a compatible solvent such as N,N-dimethylformamide at elevated temperatures (80° C.-120° C.) for extended periods of time. The bromo group may subsequently be elaborated into the acid or nitrile as above.
1,3-Disubstituted and 1,3,5-trisubstituted benzoic acids and benzonitriles may be prepared by taking advantage of readily available substituted isophthalic acid derivatives. Monohydrolysis of the diester allows selective reaction of the acid with a variety of reagents, most typically activating agents such as thioniyl chloride, oxalyl chloride or isobutyl chloroformate and the like. From the activated acid, a number of products are available. In addition to the primary amide used to form the nitrile by dehydration as mentioned above, reduction to the hydroxymethyl analog may be carried out on the mixed anhydride or acid chloride using a variety of reducing agents such as sodium borohydride in a compatible solvent such as TUE. The hydroxymethyl derivative may be further reduced to the methyl analog using catalytic hydrogenation with an appropriate source of catalyst such as palladium on carbon in an appropriate solvent such as ethanol. The hydroxymethyl group may also be used in any reaction suitable for benzylic alcohols such as acylation, alkylation, transformation to halogen and the like. Halomethylbenzoic acids of this type may also be obtained from bromination of the methyl derivative when not commercially available. Ethers obtained by alkylation of the hydroxymethyl derivatives may also be obtained from the halomethylaryl benzoate derivatives by reaction with the appropriate alcohol using an appropriate base such as potassium carbonate or sodium hydroxide in an appropriate solvent such as THF or the alcohol. When other substituents are present these may also be employed in standard transformation reactions. Treatment of anilines with acid and sodium nitrite may yield a diazonium salt, which may be transformed into a halide such as fluoride using tetrafluoroboric acid. Phenols react in the presence of a suitable base such as potassium carbonate with alkylating agents to form aromatic ethers.
A compound of formula IX, wherein G1 and/or G2 is a moiety from an intermediate or group(s) as defined by formula I may be prepared by a 1,3-dipolar cycloaddition between compounds of formula VI and VII under basic conditions using a suitable base such as sodium bicarbonate or triethylamine at suitable temperatures (0° C.-100° C.) in solvents such as toluene. Synthesis of compounds of type VI has previously been described in the literature, e.g. Kim, Jae Nyoung; Ryu, Eung K; J. Org. Chem., (1992), 57, 6649-50. 1,3-Dipolar cycloaddition with acetylenes of type VII can also be effected using substituted nitromethanes of type VIII via activation with an electrophilic reagent such as PhNCO in the presence of a base such as TEA at elevated temperatures (50° C.-100° C.). Li, C-S.; Lacasse, E.; Tetrahedron Lett., (2002) 43; 3565-3568. Several compounds of type VII are commercially available, or may be synthesized by standard methods as known by one skilled in the art.
Alternatively, compounds of formula I, which are available from a Claisen condensation of a methyl ketone X and an ester using basic conditions (see scheme 3) using such bases as sodium hydride or potassium tert-butoxide, may yield compounds of formula XI via condensation and subsequent cyclization using hydroxylamine, for example in the form of the hydrochloric acid salt, at elevated temperatures (60° C.-120° C.) to afford intermediate XII.
It is understood that for both methods, subsequent functional group transformations of intermediates such as IX and XII may be necessary. In the case of an ester group as in XII, these transformations may include, but is not limited to either of the following three procedures: a) Complete reduction using a suitable reducing agent such as LAH in solvents such as THF. b) Partial reduction using a suitable selective reducing agent such as DIBAL followed by addition of an alkylmetal reagent. c) Addition of an alkylmetal reagent such as an alkyl magnesium halide in solvents such as toluene or THF, followed by reduction with for example sodium borohydride in MeOH.
Compounds of formula I wherein X is tetrazole, as in intermediates XVI (M=H or methyl) are prepared through condensation between arylsulphonylhydrazones XIV with diazonium salts derived from anilines XIII (scheme 4). The tetrazole intermediate XV, obtained from the diazonium salt of XIII and the arylsulphonylhydrazones of cinnamaldehydes (M=H or Me) can be cleaved to provide an aldehyde (M=H) or ketone (M=Me) XV directly in a one-pot process using a reagent such as ozone or via the diol using a dihydroxylation reagent such as osmium tetroxide followed by subsequent cleavage using a reagent such as lead (IV) acetate. (J. Med. Chem., (2000), 43, 953-970).
The olefin can also be converted in one pot to the alcohol via ozonolysis followed by reduction with a reducing agent such as sodium borohydride. Aldehydes XV (M=H) may be reduced to primary alcohols of formula XVII (M=H) using well known reducing agents such as sodium or lithium borohydride, in a solvent such as MeOH, TM or DMF at temperatures between 0° C.-80° C. Secondary alcohols wherein M is not H may also be formed from aldehydes of formula XVI (M=H) via addition reactions of an organometallic reagent, for example Grignard reagents (e.g. MeMgX), in a solvent such as THF at temperatures between −78° C. to 80° C., and are typically performed between 0° C. and room temperature.
Alternatively, compounds of formula I wherein X is tetrazole, as in intermediates XVI (M=H) are prepared through condensation between arylhydrazines A with glyoxalic acid (scheme 5). The intermediate B, obtained underwent to cycloaddition with azido 2,4,6-tribromobenzene to assemble the tetrazole core to give the carboxylic acid intermediate C. The acid C can either be reduced direct with BH3 or NaBH4/BF3.Et2O or transformed to the ester derivative D prior to reduction with NaBH4 to provide alcohols of formula XVII (M=H). Partial reduction of D with for example Dibal-H could provide aldehydes which can be easily transformed into alcohols of formula XVII (M=H or Me). (J. Med. Chem. 1978, 21, 1254; Heterocycles 1995, 40: 583).
Compounds of formula XXIII containing the dihydro[1,2,4]triazole-3-thione ring may be prepared by initial N-acylation of a 4-alkylthiosemicarbazide of formula XIX using any suitable acylating agent of formula XVIII in a suitable solvent, for example pyridine DMF, DCM, THF, or acetonitrile at a temperature from −20 to 100° C. A pre-formed acylating agent such as an acid halide or ester may be employed, or an acid may be activated in situ by the treatment with standard activating reagents such as DCC, DIC, EDCI or HBTU, with or without the presence of co-reagents such as HOBt or DMAP. Formation of the acyclic intermediate XXII is followed by alkaline ring closure either spontaneously under the conditions of the acylation, or by heating at 50° C. to 150° C. in pyridine or in aqueous solvents in the presence of a base, such as NaOH, NaHCO3 or Na2CO3, with or without co-solvents such as dioxane, THE, MeOH, EtOH or DMF. The acyclic intermediate of formula XXII can also be formed by treatment of an acyl hydrazide of formula XX with a suitable isothiocyanate of formula XXI in a suitable solvent, for example IPA, DCM, THF or the like at temperatures in the range of −20 to 120° C.
Compounds of formula XXIII may then be converted to sulfones of formula XXV by initial alkylation of the sulphur atom to form intermediates of formula XXIV using primary alkyl halides such as MeI and EtI (alkyl is Me and Et respectively) in MeOH, EtOH, THF, acetone or the like at −30° C. to 100° C., followed by oxidation of intermediates XXIV using for example KMnO4 in mixtures of water and acetic acid, or MCPBA in DCM, at −20° C. to 120° C., or by using any other suitable oxidant such as Oxone.
Compounds of formula I (wherein X as drawn in formula I is either tetrazole, triazole, oxadiazole or isoxazole) may be prepared by bond formation through nucleophilic replacement of a leaving group such as alk-SO2 from compounds of formula XXV by an alcohol or alkoxide nucleophile under basic conditions. The base used may include strong hydridic bases, for example, NaH or milder bases, such as Cs2CO3, at temperatures from 0° C. to 80° C. in polar aprotic solvents such as DMF or acetonitrile. Other suitable leaving groups may include halogens, such as chloro or bromo.
In cases where Z contains an appropriate protecting group such as benzyl, methyl, t-Butyl or trialkylsilylethoxymethyl (e.g. trimethyllsilylethoxymethyl- or the SEM), various deprotection conditions included, hydrogenation under metal catalyzed conditions, acidic or Lewis acid mediated cleavage conditions (e.g. HBr/acetic acid or Dialkylaluminium chloride such as Me2AlCl) or nucleophilic conditions (e.g. Et2NCH2CH2SH.HCl NaOtBu, DMF, reflux) may be used to obtain compounds of formula I.
Alternatively, the amide substituents contained in Z can be introduced by transforming a halogen containing precursor to the corresponding ester via a metal catalysed carbonylation to introduce an alkoxycarbonyl group followed by direct aminolysis or sequentially via ester hydrolysis followed by amide formation.
Triazole XXX, wherein R-groups are defined as in formula I, may be prepared by treatment of and aryl azide XXVII with a propargylic alcohol such as XXVIII, wherein PG is H or a commonly used protective group for alcohols such as Boc, tert-butyl dimethyl silyl, acetyl, etc., in the presence of catalytic amounts of CuSO4, scheme 9. The aryl azide, XXVI, is either commercially available or may be prepared from commercially available anilines by initial diazotation followed by conversion of the diazonium salt to the corresponding azide using NaN3, (Angew. Chem. Intl. Ed., (2002), 41 (14), 2596-2599). Alternatively, XXIX, wherein LG is a leaving group such as Br or I, is treated with sodium azide and CuSO4 to give XXVII, scheme 9, (Organic Lett., (2004), 6 (22), 3897-3899). Triazole XXXII may be prepared from XXVIII, (Tetrahedron, (2005), 61(21), 4983-4987). If PG is not hydrogen in XXX the PG may be removed using conditions well established in the art.
An alternative 1,2,3-triazole regioisomer XXXII, scheme 10, may be synthesized either from a substituted triazole XXXII which may undergo a nucleophilic addition to a halogenated phenyl such as XXIX (scheme 10, e.g. LG=F), using an inorganic base such as K2CO3 in DMSO (Tetrahedron, (2001), 57 (22), 4781-4785), or from an α-hydroxy ketone XXXIV which may be reacted with an aryl hydrazine, XXXV, in the presence of e.g. cupric chloride and beating, (Synth. Commun., (2006), 36, 2461-2468). If PG is not hydrogen the PG may be removed using conditions well established in the art. This may be performed on XXXII or XXXIII.
Embodiments of the present invention will now be illustrated by the following non-limiting examples.
All starting materials are commercially available or earlier described in the literature. The 1H and 13C NMR spectra were recorded on one of a Bruker 300 at 300 MHz Bruker, DPX400 at 400 MHz or Varian +400 spectrometer at 100 MHz, using TMS or the residual solvent signal as reference. NMR measurements were made on the delta scale (δ). Mass spectra were recorded on a QTOF Global Micromass or a Waters LCMS consisting of an Alliance 2795 (LC) and a ZQ single quadrupole mass spectrometer. The mass spectrometer was equipped with an electrospray ion source operated in a positive or negative ion mode. The ion spray voltage was ±3 kV and the mass spectrometer was scanned from m/z 100-700 with a scan time of 0.8 s. Column: X-Terra MS, Waters, C8, 2.1×50 mm, 3.5 μm and the column temperature was set to 40° C. A linear gradient was applied, run at 0% to 100% acetonitrile in 4 minutes, flow rate 0.3 mL/min. Mobile phase: acetonitrile/10 mM ammonium acetate in 5% acetonitrile in MilliQ Water. Preparative chromatography was run on a Gilson autopreparative HPLC with a diode array detector. Column: XTerra MS is C8, 19×300 mm, 7 μm. Gradient with acetonitrile/0.1 M ammonium acetate in 5% acetonitrile in MilliQ Water, generally run from 20% to 60% acetonitrile, in 13 min. Flow rate: 20 mL/in in. MS-triggered prep-LC was run on a Waters autopurification LC-MS system with a diode array detector and a ZQ mass detector. Column: XTerra MS CS, 19×100 mm, 5 μm. Gradient with acetonitrile/0.1 M ammonium acetate in 5% acetonitrile in MilliQ Water, run from 0% to 100% acetonitrile, in 10 min. Flowrate: 20 mL/min. In some cases purification by a chromatotron was performed on rotating silica gel/gypsum (Merck, 60 PF-254 with calcium sulphate) coated glass sheets, with coating layer of 2 mm using a TC Research 7924T chromatotron. Alternatively Chem Elut Extraction Column (Varian, cat #1219-8002) and Mega BE-SI (Bond Elut Silica) SPE Columns (Varian, cat #12256018; 12256026; 12256034) were used during purification of the products.
Microwave heating was performed in a Smith Synthesizer Single-mode microwave cavity producing continuous irradiation at 2450 MHz (Personal Chemistry AB, Uppsala, Sweden).
2-(3-Chlorophenyl)-5-[(E)-1-methyl-2-phenylvinyl]-2H-tetrazole (ref: WO 2005/080356; 1.50 g, 5.06 mmol) was dissolved in DCM (79 mL) and ozone was bubbled through the solution for a period of 15 minutes, The solution turned from orange to a dark orange colour. The reaction completeness was checked using a 10% EtOAc: hexanes TLC solvent system. Oxygen was bubbled through the solution for an additional 5 minutes to remove any excess ozone remaining. Dimethyl sulfide (5 mL) was added to the solution and the mixture was allowed to equilibrate to room temperature. The solvent was removed under vacuum and an oily brown substance remained. A 3 cm flash column was prepared containing ˜15 cm silica and ˜3 cm sand. The column was run using a 5% EtOAc: hexanes solvent system. The eluted fractions containing the product were collected and concentrated under low pressure. Flash column chromatography (silica, 5% EtOAc: hexanes) yielded 893 mg (79.4% yield) of the title compound.
1H NMR (300 MHz, CDCl3): δ 8.22 (s, 1H), 8.11 (m, 1H), 7.54 (d, 1H), 2.85 (s, 3H).
Ethanol (270 mL) was added to (2E)-[(3-chlorophenyl)hydrazono]acetic acid (12.2 g, 68.3 mmol) followed by NaOEt (3.95 g, 206 mmol) and 2,4,6-tribromophenyl azide (26.8 g, 75.2 mmol). The resulting suspension was heated at 60° C. for 5 h. The reaction mixture was poured into water (800 mL) while hot and the precipitate was filtered and washed with water. The filtrate was stirred with charcoal, filtered and then acidified to pH 1 using concentrated HCl. The precipitate was filtered, dissolved in EtOAc and the aqueous layer separated. The organic layer was washed once with water, dried over sodium sulfate and concentrated to give the product as an red solid. The solid obtained was mixed with pre-treated ethanol (200 mL with 38 mL of acetyl chloride at 0° C.) and the reaction mixture was heated at 85° C. for 24 h and then concentrated. The residue was dissolved in DCM and washed with water, aqueous saturated sodium bicarbonate and brine. The organic layer was concentrated and the residue was purified by silica gel using hexanes:EtOAc (95:5) to give 9.42 g of the title compound as a red oil.
1H NMR (300 MHz, CDCl3): δ 8.04 (s, 1H), 8.02 (d, 1H), 7.51 (t, 1H), 7.36 (d, 1H), 4.59 (q, 2H), 2.49 (s, 3H), 1.51 (t, 3H).
Example 3 was prepared according to a procedure for (1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethyl acetate (WO 2007/040982).
1H NMR
Example 4 was prepared according to a procedure for (1R)-1-[5-(3-chlorophenyl)isoxazol-3-yl]ethanol (WO 2005/080356).
1H NMR
4-Iodobenzohydrazide (3.87 g, 14.8 mmol) and methyl isothiocyanate (1.18 g, 11.2 mmol) were stiffed in MeOH (30 mL) at 60° C. for 30 min. Sodium hydroxide (0.65 g, 16.2 mmol) in water (5 mL) was added to the reaction and it was allowed to stir overnight at 60° C. The reaction was concentrated and the product residue was stirred in water and 3 M hydrochloric acid and then filtered to give the title compound as white solid (4.3 g, 92% yield).
1H NMR (300 MHz, CDCl13): δ 7.86 (m, 2H), 7.33 (m, 21), 3.60 (s, 3H).
In a similar manner the following compound was synthesized:
1H NMR
The title compound from Example 8.1 (4.3 g, 13.5 mmol) and sodium hydroxide (1.08 g, 27.1 mmol) were stirred in water (27 mL) and ethanol (8 mL). MeI (1.34 mL, 21.6 mmol) was added slowly to the reaction. The reaction was allowed to stir overnight at r.t. The reaction mixture was extracted with portions of DCM. The organic extracts were dried over anhydrous sodium sulfate, filtered and concentrated to yield the crude residue that was purified by flash chromatography (0-10% MeOH in EtOAc) to give title compound (1.88 g, 42% yield) as a yellow solid.
1H NMR (300 MHz, CDCl3): δ 7.86 (d, 2H), 7.38 (d, 2H), 3.56 (s, 3H), 2.74 (s, 3H).
1H NMR
The title compound of Example 6.1 (1.88 g, 5.67 mmol) was dissolved in acetic acid (20 mL) and KMnO4 (1.34 g, 8.51 mmol) dissolved in water (20 mL) was added slowly. The reaction mixture stirred for 3 h at room temperature. The reaction mixture was quenched with aqueous Na2SO3 (2.14 g, 17 mmol) and then neutralized with NaOH (aqueous). The reaction was extracted with CH2Cl2 and the organic extracts were dried, filtered and concentrated to afford the crude mixture which was purified by flash chromatography to give the title compound (1.56 g, 76%) as a white solid.
1H NMR (300 MHz, CDCl3): δ 7.92 (d, 2H), 7.39 (d, 2H), 3.96 (s, 3H), 3.59 (s, 3H).
The title compound of Example 6.2 (3.96 g, 13.9 mmol) was dissolved in MeOH (50 mL) and Oxone (potassium peroxomonosulfate, 17.1 g, 27.8 mmol) dissolved in water (65 mL) was added slowly. The reaction mixture stirred for 24 h. The reaction was partially concentrated, poured into water and extracted with chloroform. The organic extracts were dried, filtered and concentrated to afford the title compound (3.36 g, 76%) as a white fluffy solid.
1H NMR (300 MHz, CDCl3): δ 8.79 (d, 1H), 8.24 (d, 1H), 8.03 (dd, 1H), 4.38 (s, 3H), 3.60 (s, 3B).
The title compound from Example 7.1 (0.600 g, 1.65 mmol), the title compound from Example 17.2 (0.482 g, 2.15 mmol) and cesium carbonate (1.62 g, 4.96 mmol) were stirred in dimethylformamide (8 mL) at 65° C. for 6 h. The reaction mixture was partitioned between water and DCM and the aqueous layer was extracted with portions of DCM. The organic extracts were dried over anhydrous sodium sulfate, filtered and concentrated. The product was purified by column chromatography (1:1, EtOAc/hexane) to give the title compound (0.209 g, 25% yield).
H1 NMR (300 MHz, CDCl3): δ 8.15 (m, 4H), 8.03 (m, 1H), 7.84 (d, 2H), 7.58 (m, 1H), 7.50 (t, 1H), 7.40 (d, 2H), 6.40 (q, 11, 3.55 (s, 3H), 1.95 (d, 3H).
In a similar manner the following compounds were synthesized:
1H NMR
1H NMR
1H NMR
The title compound from Example 8.1 (0.305 g, 0.6 mmol), palladium acetate (6.73 mg, 0.030 mmol) and 1,1′-bis(diphenylphosphino)-ferrocene-dichloropalladium (0.33 g, 0.6 mmol) were stirred with dimethylformamide (1.2 mL), MeOH (0.3 mL) and triethylamine (0.16 mL, 1.02 mmol) under a carbon monoxide atmosphere at 70° C. overnight. The reaction mixture was partitioned between water and DCM and the aqueous layer was extracted with portions of DCM. The organic extracts were dried over anhydrous sodium sulfate, filtered and concentrated and purified by column chromatography (50-100% EtOAc/hexanes) to yield the title compound (0.15 g, 57%).
1H NMR (300 MHz, CDCl3): δ 8.13 (m, 3H), 8.01 (d, 1H), 7.73 (m, 21-1), 7.57 (m, 1H), 7.46 (t, 1H), 6.38 (q, 1H), 3.91 (s, 3H), 3.55 (s, 3H), 1.72 (d, 3H).
In a similar manner the following compounds were synthesized:
1H NMR
1H NMR
1H NMR
The title compound from Example 9.1 (0.75 g, 0.17 mmol) was stirred in MeOH or THF and aqueous ammonium hydroxide (3 mL) was added. The reaction mixture was heated at 50° C. overnight. The reaction mixture was diluted with water and extracted with portions of chloroform. The organic extracts were dried over anhydrous sodium sulfate, filtered and concentrated to give the title compound (0.030 g, 41%) as a white solid.
1H NMR (300 MHz, CDCl3): δ 8.08 (m, 1H), 7.97 (m, 3H), 7.65 (d, 2H), 7.54 (m, 1H) 7.45 (m, 1H), 6.29 (m, 1H), 3.54 (s, 3H), 3.24 (br, 2H), 1.90 (d, 3H).
In a similar manner the following compounds were synthesized:
1H NMR
1H NMR
1H NMR
Functional Assessment of mGluR5 Antagonism in Cell Lines Expressing mGluR5D
The properties of the compounds of the invention can be analyzed using standard assays for pharmacological activity. Examples of glutamate receptor assays are well known in the alt as described in for example Aramori et al., Neuron 8:757 (1992), Tanabe et al., Neuron 8:169 (1992), Miller et al., J. Neuroscience 15: 6103 (1995), Balazs, et al., J. Neurochemistry 69:151 (1997). The methodology described in these publications is incorporated herein by reference. Conveniently, the compounds of the invention can be studied by means of an assay (FLIPR) that measures the mobilization of intracellular calcium, [Ca2+]i in cells expressing mGluR5 or another assay (IP3) that measures inositol phosphate turnover.
Cells expressing human mGluR5d as described in WO97/05252 cultured in a mixture of high glucose DMEM with Glutamax (31966-021)(500 mL), 10% dialyzed fetal bovine serum (Hyclone #SH30079.03)(56 mL), 200 μg/in L Hygromycin B (Invitrogen 45-0430, 50 mg/mL)(2.2 mL), 200 μg/mL Zeocin (Invitrogen #R250-01; 100 mg/mL)(1.1 mL) are seeded at a density of 100,000 cells per well on collagen coated clear bottom 96-well plates with black sides and cells were allowed to adhere over night before experiments. All assays are done in a buffer containing 146 mM NaCl, 5 mM KCl, 1 mM MgCl2, 1 mM CaCl2, 20 mM HEPES, 1 mg/mL glucose and 1 mg/mL BSA Fraction IV (pH 7.4). Cell cultures in the 96-well plates are loaded for 60 minutes in the above mentioned buffer containing 6 μM of the acetoxymethyl ester form of the fluorescent calcium indicator fluo-3 (Molecular Probes, Eugene, Oreg.) in 0.025% pluronic acid (a proprietary, non-ionic surfactant polyol—CAS Number 9003-11-6). Following the loading period the fluo-3 buffer is removed and replaced with fresh assay buffer. FLIPR experiments are done using a laser setting of 0.700 W and a 0.4 second CCD camera shutter speed with excitation and emission wavelengths of 488 nm and 562 nm, respectively. Each experiment is initiated with 160 μl of buffer present in each well of the cell plate. A 40 μl addition from the antagonist plate was followed by a 50 μL addition from the agonist plate. A 30 minutes, in dark at 25° C., interval separates the antagonist and agonist additions. The fluorescence signal is sampled 50 times at 1-second intervals followed by 3 samples at 5-second intervals immediately after each of the two additions. Responses are measured as the difference between the peak heights of the response to agonist less the background fluorescence within the sample period. IC50 determinations are made using a linear least squares fitting program.
An additional functional assay for mGluR5d is described in WO97/05252 and is based on phosphatidylinositol turnover. Receptor activation stimulates phospholipase C activity and leads to increased formation of inositol 1,4,5,triphosphate (IP3). GHEK stably expressing the human mGluR5d are seeded onto 24 well poly-L-lysine coated plates at 40×104 cells/well in media containing 1 μCi/well [3H] myo-inositol. Cells were incubated overnight (16 h), then washed three times and incubated for 1 h at 37° C. in HEPES buffered saline (146 mM NaCl, 4.2 mM KCl, 0.5 mM MgCl2 0.1% glucose, 20 mM HEPES, pH 7.4) supplemented with 1 unit/mL glutamate pyruvate transaminase and 2 mM pyruvate. Cells are washed once in HEPES buffered saline and pre-incubated for 10 min in HEPES buffered saline containing 10 mM LiCl. Compounds are incubated in duplicate at 37° C. for 15 min, then either glutamate (80 μM) or DHPG (30 μM) is added and incubated for an additional 30 min. The reaction is terminated by the addition of 0.5 mL perchloric acid (5%) on ice, with incubation at 4° C. for at least 30 min. Samples are collected in 15 mL polyproplylene tubes and inositol phosphates are separated using ion-exchange resin (Dowex AG1-X8 formate form, 200-400 mesh, BIORAD) columns. Inositol phosphate separation was done by first eluting glycero phosphatidyl inositol with 8 mL 30 mM ammonium formate. Next, total inositol phosphates is eluted with 8 mL 700 mM ammonium formate/100 mM formic acid and collected in scintillation vials. This eluate is then mixed with 8 mL of scintillant and [3H] inositol incorporation is determined by scintillation counting. The dpm counts from the duplicate samples are plotted and IC50 determinations are generated using a linear least squares fitting program.
FLIPR Fluorometric Imaging Plate reader
GLAST Glutamate/aspartate transporter
HEPES 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid (buffer)
IP3 Inositol triphosphate
Generally, the compounds were active in the assay above with IC50 values less than 10000 nM. In one aspect of the invention, the IC50 value is less than 1000 nM. In a further aspect of the invention, the IC50 value is less than 100 NM.
Brain to plasma ratios are estimated in female Sprague Dawley rats. The compound is dissolved in water or another appropriate vehicle. For determination of brain to plasma ratio the compound is administrated as a subcutaneous, or an intravenous bolus injection, or an intravenous infusion, or an oral administration. At a predetermined time point after the administration a blood sample is taken with cardiac puncture. The rat is terminated by cutting the heart open, and the brain is immediately retained. The blood samples are collected in heparinized tubes and centrifuged within 30 minutes, in order to separate the plasma from the blood cells. The plasma is transferred to 96-well plates and stored at −20° C. until analysis. The brains are divided in halt and each half is placed in a pre-tarred tube and stored at −20° C. until analysis. Prior to the analysis, the brain samples are thawed and 3 mL/g brain tissue of distilled water is added to the tubes. The brain samples are sonicated in an ice bath until the samples are homogenized. Both brain and plasma samples are precipitated with acetonitrile. After centrifugation, the supernatant is diluted with 0.2% formic acid. Analysis is performed on a short reversed-phase HPLC column with rapid gradient elution and MSMS detection using a triple quadrupole instrument with electrospray ionisation and Selected Reaction Monitoring (SRM) acquisition. Liquid-liquid extraction may be used as an alternative sample clean-up. The samples are extracted, by shaking, to an organic solvent after addition of a suitable buffer. An aliquot of the organic layer is transferred to a new vial and evaporated to dryness under a stream of nitrogen. After reconstitution of the residuals the samples are ready for injection onto the HPLC column.
Generally, the compounds according to the present invention are peripherally restricted with a drug in brain over drug in plasma ratio in the rat of <0.5. In one embodiment, the ratio is less than 0.15.
Rat liver microsomes are prepared from Sprague-Dawley rats liver samples. Human liver microsomes are either prepared from human liver samples or acquired from BD Gentest. The compounds are incubated at 37° C. at a total microsome protein concentration of 0.5 mg/mL in a 0.1 mol/L potassium phosphate buffer at pH 7.4, in the presence of the cofactor, NADPH (1.0 mmol/L). The initial concentration of compound is 1.0 μmol/L. Samples are taken for analysis at 5 time points, 0, 7, 15, 20 and 30 minutes after the start of the incubation. The enzymatic activity in the collected sample is immediately stopped by adding a 3.5 times volume of acetonitrile. The concentration of compound remaining in each of the collected samples is determined by means of LC-MS. The elimination rate constant (k) of the mGluR5 inhibitor is calculated as the slope of the plot of In[mGluR5 inhibitor] against incubation time (minutes). The elimination rate constant is then used to calculate the half-life (T½) of the mGluR5 inhibitor, which is subsequently used to calculate the intrinsic clearance (CLint) of the mGluR5 inhibitor in liver microsomes as: CLint.=(In2×incubation volume)/(T½×protein concentration)=μl/min/mg
Adult Labrador retrievers of both genders, trained to stand in a Pavlov sling, are used. Mucosa-to-skin esophagostomies are formed and the dogs are allowed to recover completely before any experiments are done.
In brief, after fasting for approximately 17 h with free supply of water, a multilumen sleeve/sidehole assembly (Dentsleeve, Adelaide, South Australia) is introduced through the esophagostomy to measure gastric, lower esophageal sphincter (LES) and esophageal pressures. The assembly is perfused with water using a low-compliance manometric perfusion pump (Dentsleeve, Adelaide, South Australia). An air-perfused tube is passed in the oral direction to measure swallows, and an antimony electrode monitored pH, 3 cm above the LES. All signals are amplified and acquired on a personal computer at 10 Hz.
When a baseline measurement free from fasting gastric/LES phase III motor activity has been obtained, placebo (0.9% NaCl) or test compound is administered intravenously (i.v., 0.5 mL/kg) in a foreleg vein. Ten min after i.v. administration, a nutrient meal (10% peptone, 5% D-glucose, 5% Intralipid, pH 3.0) is infused into the stomach through the central lumen of the assembly at 100 mL/min to a final volume of 30 mL/kg. The infusion of the nutrient meal is followed by air infusion at a rate of 500 mL/min until an intragastric pressure of 10±1 mmHg is obtained. The pressure is then maintained at this level throughout the experiment using the infusion pump for further air infusion or for venting air from the stomach. The experimental time from start of nutrient infusion to end of air insufflation is 45 min. The procedure has been validated as a reliable means of triggering TLESRs.
TLESRs is defined as a decrease in lower esophageal sphincter pressure (with reference to intragastric pressure) at a rate of >1 mmHg/s. The relaxation should not be preceded by a pharyngeal signal ≦2 s before its onset in which case the relaxation is classified as swallow-induced. The pressure difference between the LES and the stomach should be less than 2 mmHg, and the duration of the complete relaxation longer than 1 s.
| Number | Date | Country | |
|---|---|---|---|
| 60982937 | Oct 2007 | US |
