ES2354230T3 - DERIVATIVES OF N- (PHENYLMETILE) -2- (1H-PIRAZOL-4-IL) ACETAMIDE AS AN ANTIGONIST OF P2X7 FOR THE TREATMENT OF PAIN, INFLAMMATION AND NEURODEGENERATION. - Google Patents

Abstract

A compound of formula (I) or its pharmaceutically acceptable salt: ** (See formula) ** in which: R1 and R2 represent C1-6 alkyl, phenyl, or C3-6 cycloalkyl, any one being optionally substituted with 1, 2 or 3 halogen atoms; R3 and R4 independently represent hydrogen or C1-3 alkyl; R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl, and any of said C1-6 alkyl, C2 alkenyl -6, C2-6 alkynyl, C3-6 cycloalkyl or phenyl is optionally substituted with 1, 2 or 3 halogen atoms; or R8 and R9, together with the carbon atoms to which they are attached, form a benzene ring that is optionally substituted with 1, 2 or 3 halogen atoms; or R4 and R5, together with the carbon atoms to which they are attached form a C5-7 cycloalkyl; with the proviso that when R5 and R9 are both selected from hydrogen or fluorine, at least one of R6, R7 and R8 is a halogen atom, or R6, R7 and R8 are selected from the group consisting of hydrogen, methyl and CF3, and one, but not more than one of R6, R7 and R8 is methyl or CF3.

Description

The present invention relates to heterocyclic amide derivatives that modulate the function of the P2X7 receptor and that are capable of antagonizing the effects of ATP on the P2X7 receptor (P2X7 receptor antagonists); to processes for its preparation; to pharmaceutical compositions containing them; and to the use of said compounds in therapy.

The P2X7 receptor is a ligand-regulated ionic channel that is expressed in hematopoietic lineage cells, for example macrophages, microglial cells, mast cells and lymphocytes (T and B) (see, for example, Collo, et al. Neuropharmacology, vol 36, pp. 1277-1283 (1997)), and is activated by extracellular nucleotides, particularly adenosine triphosphate (ATP). The activation of P2X7 receptors has been implicated in giant cell formation, degranulation, cytolytic cell death, CD62L propagation, regulation of cell proliferation and release of proinflammatory cytokines, such as interleukin 1 beta (IL-1�) (for example Ferrari, et al., J. Immunol., vol. 176, pp. 38773883 (2006)) and tumor necrosis factor alpha (TNF�) (for example Hide, et al., Journal of Neurochemistry, vol. 75, pp. 965-972 (2000)). P2X7 receptors are also located in cells that have antigens, keratinocytes, parotid cells, hepatocytes, erythrocytes, erythroleukemic cells, monocytes, fibroblasts, bone marrow cells, neurons and renal mesangial cells. In addition, the P2X7 receptor is expressed by presynaptic terminals in the central and peripheral nervous systems, and has been shown to mediate the release of glutamate in glial cells (Anderson, C. et al., Drug. Dev. Res., Vol. 50, page 92 (2000)).

The location of the P2X7 receptor to key cells of the immune system, together with its ability to release important inflammatory mediators from these cells, suggests a potential role of P2X7 receptor antagonists in the treatment of a wide range of diseases including pain and disorders. neurodegenerative Recent in vivo preclinical studies have directly implicated the P2X7 receptor in inflammatory pain and neuropathic pain (Dell'Antonio et al., Neurosci. Lett., Vol. 327, pp. 87-90 (2002); Chessell, IP. , et al., Pain, vol. 114, pp. 386396 (2005); Honore et al., J. Pharmacol. Exp. Ther., vol. 319, pp. 1376-1385 (2006)) while there is data in vitro suggesting that P2X7 receptors mediate death induced by microglial cells of cortical neurons (Skaper, SD, et al., Glia, vol. 54, pp. 234-242 (2006)). In addition, the increase in the P2X7 receptor has been observed around �-amyloid plaques in a transgenic mouse model of Alzheimer's disease (Parvathenani, L. et al., J. Biol. Chem., Vol. 278 (15), pp. 13309-13317 (2003)).

WO 2005/019182 (Bayer Healthcare AG) describes derivatives of

pyrazole with P2X7 antagonistic activity that are substituted at position 4 with

a methylbenzamide group.

The present invention provides compounds that modulate the function of P2X7 receptors and are capable of antagonizing the effects of ATP on the P2X7 receptor (P2X7 receptor antagonists). In a first aspect, a compound of formula (I), or its pharmaceutically acceptable salt, is provided:

image 1

in which: R1 and R2 represent C1-6 alkyl, phenyl, or C3-6 cycloalkyl, any one being optionally substituted with 1, 2 or 3 halogen atoms; R3 and R4 independently represent hydrogen or C1-3 alkyl;

R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl, and any of said C1-6 alkyl, alkenyl C2-6, C2-6 alkynyl, C3-6 cycloalkyl or phenyl is optionally substituted with 1, 2 or 3 halogen atoms; or R8 and R9, together with the carbon atoms to which they are attached, form a benzene ring that is

20 optionally substituted with 1, 2 or 3 halogen atoms;

or R4 and R5, together with the carbon atoms to which they are attached form a C5-7 cycloalkyl; with the proviso that when R5 and R9 both hydrogen or fluorine are selected, at least one of R6, R7 and R8 is a halogen atom, or R6, R7 and R8 are

25 selected from the group consisting of hydrogen, methyl and CF3, and one, but not more than one of R6, R7 and R8 is methyl or CF3.

In one embodiment of the invention, the compound of formula (I) is different from N- [1- (4-bromophenyl) propyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide.

In one embodiment of the invention there is provided a compound of formula (IA), or its pharmaceutically acceptable salt:

image2

in which: R1 and R2 represent C1-6 alkyl, phenyl, or C3-6 cycloalkyl, any one being optionally substituted with 1, 2 or 3 halogen atoms; R3, R4, R5, R6 and R7 independently represent hydrogen, halogen, cyano,

C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-6 cycloalkyl or phenyl, and any such said C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-6 cycloalkyl or phenyl optionally is substituted with 1, 2 or 3 halogen atoms; or R6 and R7, together with the carbon atoms to which they are attached, form a benzene ring that is optionally substituted with 1, 2 or 3 halogen atoms;

15 provided that when R3 and R7 are both selected from hydrogen or fluorine, at least one of R4, R5 and R6 is a halogen atom, or not more than one of R4, R5 and R6 is a CF3 group. In one embodiment of the invention there is provided a compound of formula (IB), or its pharmaceutically acceptable salt:

image3

in which:

R1 and R2 represent C1-6 alkyl, phenyl, or C3-6 cycloalkyl, any of which may be optionally substituted with 1, 2 or 3 halogen atoms; R3, R4, R5, R6 and R7 independently represent hydrogen, halogen, cyano, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl; and any of said C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl may be optionally substituted with 1, 2 or 3 halogen atoms; with the proviso that when R3 and R7 both represent hydrogen, at least one of R4, R5 and R6 is a halogen atom.

As used herein, the term "alkyl" (when used as a group or as part of a group) refers to a linear or branched hydrocarbon chain containing the indicated number of carbon atoms. For example, C1-6 alkyl means a linear or branched hydrocarbon chain containing at least 1 and at most 6 carbon atoms. Examples of alkyl include, but are not limited to: methyl (Me), ethyl (Et), n-propyl, i-propyl, n-hexyl and i-hexyl.

As used herein, the term "alkenyl" refers to linear or branched hydrocarbon chains containing the indicated number of carbon atoms, in which at least one carbon-carbon bond is a double bond. Examples of alkenyl include, but are not limited to, ethenyl, propenyl, n-butenyl, ibutenyl, n-pentenyl and i-pentenyl.

As used herein, the term "alkynyl" refers to a linear or branched hydrocarbon chain containing the indicated number of carbon atoms, in which at least one carbon-carbon bond is a triple bond. Examples of alkynyl include, but are not limited to, ethynyl, propynyl, butynyl, pentinyl, n-pentinyl, i-hexinyl and n-hexinyl.

The term "cycloalkyl", unless otherwise indicated, means a non-aromatic closed ring of 3 to 8 members, for example cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

The term "halogen" is used herein to describe, unless otherwise indicated, a group selected from fluorine, chlorine, bromine or iodine.

In certain embodiments of the invention, R1 and R2 independently represent unsubstituted C1-6 alkyl, trifluoromethyl, phenyl or C3-6 cycloalkyl. In one embodiment, R1 and R2 independently represent unsubstituted C1-6 alkyl

or trifluoromethyl. In another embodiment, R1 and R2 independently represent methyl or trifluoromethyl. In another embodiment, R1 represents trifluoromethyl, and R2 represents methyl.

In certain embodiments of the invention, R3 and R4 independently represent hydrogen or methyl. In one embodiment, R3 and R4 both represent hydrogen.

In certain embodiments of the invention, R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, trifluoromethyl or unsubstituted C1-6 alkyl. In another embodiment, R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, methyl or trifluoromethyl. In one embodiment, R5, R6, R7, R8 and R9 independently represent hydrogen, chlorine, fluorine, bromine, methyl or trifluoromethyl.

In one embodiment of the invention, a compound of formula (I) is provided,

or its pharmaceutically acceptable salt, in which: R1 and R2 independently represent unsubstituted C1-6 alkyl, trifluoromethyl, phenyl

or C3-6 cycloalkyl; R3 and R4 independently represent hydrogen or methyl; R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, trifluoromethyl or unsubstituted C1-6 alkyl;

or R4 and R5, together with the carbon atoms to which they are attached form a C5-7 cycloalkyl; with the proviso that when R5 and R9 both hydrogen or fluorine are selected, at least one of R6, R7 and R8 is a halogen atom, or R6, R7 and R8 are select from the group consisting of hydrogen, methyl and CF3, and one, but not more than one of R6, R7 and R8 is methyl or CF3.

In another embodiment, a compound of formula (I), or its pharmaceutically acceptable salt, is provided in which: R1 and R2 independently represent methyl or trifluoromethyl; R3 and R4 both represent hydrogen; and R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, trifluoromethyl or methyl; with the proviso that when R5 and R9 are both selected from hydrogen or fluorine, at least one of R6, R7 and R8 is a halogen atom, or R6, R7 and R8 are selected from the group consisting of hydrogen, methyl and CF3, and one, but not more than one of R6, R7 and R8 is methyl or CF3.

Particular compounds according to the invention include the compounds of examples 1-37 shown below, or their pharmaceutically acceptable salts.

P2X7 antagonists may be useful for preventing, treating or alleviating a variety of pain states (eg, neuropathic pain, chronic inflammatory pain and visceral pain), inflammation and neurodegeneration, in particular Alzheimer's disease. P2X7 antagonists may also constitute therapeutic agents useful for the treatment of rheumatoid arthritis and inflammatory bowel disease.

The compounds of the present invention that modulate the function of P2X7 receptors and that are capable of antagonizing the effects of ATP on the P2X7 receptor (antagonists of P2X7 receptors) may be competitive antagonists, inverse agonists, negative allosteric modulators or indirect modulators of The function of the receiver.

Certain compounds of formula (I) may, in some circumstances, form their acid addition salts. It will be appreciated that for use in medicine, the compounds of formula (I) can be used as salts, in which case the salts must be pharmaceutically acceptable. Pharmaceutically acceptable salts include those described by Berge, Bighley and Monkhouse, J. Pharm. Sci., 1977, 66, 1-19. The basic compounds of formula (I) can form salts with pharmaceutically acceptable acids, including inorganic and organic acids. Such acids include acetic acid, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, phosphenic, pantothenic, sucrose sulfuric, tartaric, p-toluenesulfonic and the like.

Examples of pharmaceutically acceptable salts include those formed from maleic, fumaric, benzoic, ascorbic, pamoic, succinic, hydrochloric, sulfuric, bismethylenesalicylic, methanesulfonic, ethanedisulfonic, propionic, tartaric, salicylic, citric, gluconic, aspartic, stearic, aspartic acids palmitic, itaconic, glycolic, p-aminobenzoic, glutamic, benzenesulfonic, cyclohexylsulfamic, phosphoric and nitric.

The compounds of formula (I) can be prepared in crystalline or non-crystalline form, and, if it is in crystalline form, they can optionally be solvated, for example as the hydrate. This invention includes within its scope stoichiometric solvates (for example, hydrates) as well as compounds containing varying amounts of solvent (for example, water).

Certain compounds of formula (I) may exist in stereoisomeric forms (eg, diastereomers and enantiomers) and the invention extends to each of these stereoisomeric forms and mixtures thereof, including racemates. The different stereoisomeric forms can be separated from each other by the usual methods, or any given isomer can be obtained by stereospecific or asymmetric synthesis. The invention also extends to any tautomeric form and its mixtures.

The present invention also includes isotopically labeled compounds that are identical to those listed in formula (I) and following, except for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the mass Atomic or mass number that is most commonly found in nature. Examples of isotopes that can be incorporated into compounds of the invention include hydrogen, carbon, nitrogen, oxygen, phosphorus, fluorine, iodine and chlorine isotopes, such as 3H, 11C, 14C, 18F, 123I and 125I.

The compounds of the present invention and the pharmaceutically acceptable salts of said compounds containing the aforementioned isotopes and / or other isotopes of other atoms are within the scope of the present invention. The isotope-labeled compounds of the present invention, for example those in which radioactive isotopes, such as 3H or 14C are incorporated, are useful in drug and / or tissue distribution assays. Particularly preferred are tritium isotopes, i.e. 3H, and carbon-14, i.e. 14C, for their ease of preparation and detectability. The 11C and 8F isotopes are particularly useful in PET (positron emission tomography), and the 125I isotopes are particularly useful in SPECT (single photon emission computed tomography). PET and SPECT are useful in brain imaging. In addition, replacement with heavier isotopes, such as deuterium, that is, 2H, may provide some therapeutic advantages that result from greater metabolic stability, for example, greater in vivo half-life or lower dosage requirements, and therefore in some cases. may be preferred In general, the isotope-labeled compounds of formula (I) and following of this invention can be prepared by performing the procedures described in the schemes and / or in the examples presented below, substituting an unlabeled isotope reagent for an isotope-labeled reagent. easily available

Compound Preparation

image3

The compounds of formula (I), in which the variables are as defined above, and their salts and solvates, can be prepared by the methodology described below, which constitutes another aspect of the present invention. A process according to the invention for preparing a compound of formula (I) comprising:

(a) coupling a carboxylic acid of formula (2) (or its activated derivative) with an amine of formula (3) (see scheme 1), in which R1, R2, R3, R4, R5, R6, R7, R8 and

10 R9 are as defined above. Compounds (2) and (3) are optionally protected;

(b) deprotecting a compound of formula (I) that is protected. Examples of protecting groups and the means to eliminate them can be found in T.W. Greene and P.G.M. Wuts, Protective Groups in Organic Synthesis (J. Wiley and Sons, 3rd ed.

15 1999); or

(c) interconversion of the compounds of formula (I) into other compounds of formula (I). Examples of conventional interconversion procedures include epimerization, oxidation, reduction, alkylation, aromatic substitution, nucleophilic substitution, amide coupling and ester hydrolysis.

twenty

Scheme 1

image3

The coupling of an acid of formula (2) and an amine of formula (3) typically comprises the use of activating agents, such as water soluble carbodiimide or polymeric carbodiimide, 1-hydroxybenzotriazole (HOBT) or 1 -hydroxy-7-azabenzotriazole (HOAt), and optionally a suitable base, such as a tertiary alkylamine (for example, diisopropylethylamine, N-ethylmorpholine, triethylamine) or pyridine, in a suitable solvent, such as DMF and / or dichloromethane, and a suitable temperature, for example, between 0 ° C and room temperature. Alternatively, the coupling of (2) and (3) can be achieved by treatment with O- (7-azabenzotriazol-1-yl) -N, N, N ', N-tetramethyluronium hexafluorophosphate and a suitable tertiary alkylamine , such as diisopropylethylamine, in a suitable solvent, such as dimethylformamide, at a suitable temperature such as room temperature. When the compound of formula (2) is an activated derivative (for example, an acid chloride, a mixed anhydride, an active ester (for example, Oacilisourea)), the process (a) typically comprises the treatment of said amine activated derivative (Ogliaruso, MA, Wolfe, JF, in The Chemistry of Functional Groups (Ed. Patai, S.), Suppl. B: The Chemistry of Acid Derivatives, pt. 1 (John Wiley and Sons, 1979) , pp. 442-448; Beckwith, ALJ, in The Chemistry of

20 Functional Groups (Ed. Patai, S.), supl. B: The Chemistry of Amides (Ed. Zabricky, J.) (John Wiley and Sons, 1970), pp. 73 ff. Representative methods for the preparation of the compounds of formula

(2) are shown in schemes 2-3 below:

Scheme 2

image3

wherein R1 and R2 are as defined above, and P2 represents a suitable protecting group 5, such as C1-6 alkyl, and L1 represents a suitable leaving group,

such as a halogen atom (for example, iodine, chlorine or bromine). An analogous process has been described previously (US 4,146,721). Step (i) typically comprises the use of a suitable solvent, such

as a mixture of dioxane / water or dimethylformamide, and a suitable base, such

10 as potassium hydroxide or sodium hydride, at a suitable temperature, for example, between 0 ° C and room temperature. Step (ii) typically comprises the use of hydrazine (7) or a salt (for example, HCl) thereof, in a suitable solvent, such as ethanol. Reaction mixtures, typically, are heated to a suitable temperature, such as reflux temperature.

Step (iii) typically comprises a conventional process for the conversion of a carboxylic ester into an acid, such as the use of an appropriate hydroxide salt (for example, lithium hydroxide) in an appropriate solvent, such as a mixture of tetrahydrofuran and water, at a suitable temperature, such as 50 ° C, or the use of an appropriate acid (eg, trifluoroacetic acid) in a

20 appropriate solvent, such as dichloromethane, at a suitable temperature, such as room temperature.

Scheme 3

image3

wherein R1 and R2 are as defined above, P3 represents a suitable protecting group, such as 2- (trimethylsilyl) ethoxymethyl, X represents a suitable exchangeable group 5, such as halogen (for example, bromine or iodine), and L2 represents a suitable leaving group, such as a sulfonate ester (for example, methanesulfonyl ester).

Step (i) typically comprises a treatment with a suitable protecting group using a suitable reagent, such as {2 - [(chloromethyl) oxy] ethyl} (trimethyl) silane chloride, in a suitable solvent, such as tetrahydrofuran, with a base

10, such as sodium hydride, at a suitable temperature, such as 5 ° C. Step (ii) typically comprises the treatment of (10) with a suitable alkyl lithium species, such as n-butyllithium, and a suitable carbonylating agent, such as dimethylformamide, in a suitable solvent, such as tetrahydrofuran, and at a suitable temperature, such as between -78 ° C and room temperature.

Step (iii) typically comprises reducing (11) using a suitable reducing agent, such as sodium borohydride, in a suitable solvent, such as ethanol, and at a suitable temperature, such as between 0 ° C and ambient temperature

Step (iv) typically comprises the treatment of (12) with a suitable sulfonyl chloride, such as methanesulfonyl chloride, and a suitable base, such as triethylamine, in a suitable solvent, such as dichloromethane, and suitable temperature, such as between 0 ° C and room temperature.

Step (v) typically comprises the treatment of (13) with a suitable cyanide salt, such as potassium cyanide, in a suitable solvent, such as dimethyl sulfoxide, and at a suitable temperature, such as between room temperature and 80 ° C.

Step (vi) typically comprises treating (14) with a suitable acid, such as 5 N hydrochloric acid, in a suitable solvent, such as 1,4-dioxane, at a suitable temperature, such as 100 ° C.

Compounds of general formulas (3), (4), (5), (7) and (9) can typically be obtained from commercial sources, or can be prepared by those skilled in the art using methods described in the chemical literature (or using analogous methods).

Pharmaceutically acceptable salts may be prepared in a conventional manner by a reaction with the appropriate acid or acid derivative. Clinical indications

It is believed that since the compounds of the present invention modulate the function of P2X7 receptors and are capable of antagonizing the effects of ATP on the P2X7 receptor, they may be useful in the treatment of pain, which includes acute pain, chronic pain, joint pain. chronic, musculoskeletal pain, neuropathic pain, inflammatory pain, visceral pain, cancer-associated pain, migraine-associated pain, tension headache and histamine headaches, pain associated with intestinal function disorders, neck and back pain, associated pain with sprains and strains, sympathetic reflex syndrome; myositis, pain associated with the flu or with other viral infections, such as the common cold, pain associated with rheumatic fever, pain associated with myocardial ischemia, postoperative pain, chemotherapy pain to fight cancer, headaches, toothache and dysmenorrhea .

Chronic joint pain conditions include rheumatoid arthritis, osteoarthritis, rheumatoid spondylitis, gouty arthritis and juvenile arthritis.

Pain associated with functional bowel disorders includes dyspepsia without ulcer, non-cardiac chest pain and irritable bowel syndrome.

Neuropathic pain syndromes include: diabetic neuropathy, sciatica, nonspecific low back pain, trigeminal neuralgia, multiple sclerosis pain, fibromyalgia, HIV-related neuropathy, post-herpetic neuralgia, trigeminal neuralgia and pain caused by physical trauma, amputation, syndrome of the phantom limb, spinal surgery, cancer, toxins or chronic inflammatory conditions. In addition, neuropathic pain conditions include pain associated with normally non-painful sensations, such as "tingling" (paraesthesia and dysesthesia), increased sensitivity to touch (hyperesthesia), painful sensation after an innocuous stimulus (dynamic, static allodynia, thermal or cold), increased sensitivity to harmful stimuli (thermal, cold or mechanical hyperalgesia), continued pain after stimulus removal (hyperpathy), or an absence or deficit in the selective sensory pathways (hypoalgesia).

Other conditions that could potentially be treated with the compounds of the present invention include fever, inflammation, immunological diseases, diseases of abnormal platelet function (eg, occlusive vascular diseases), impotence or erectile dysfunction; bone disease characterized by abnormal bone metabolism or reabsorption; hemodynamic side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase 2 (COX-2) inhibitors, cardiovascular diseases; neurodegenerative diseases and neurodegeneration, neurodegeneration following trauma, tinnitus, dependence on a dependency inducing agent, such as opioids (for example morphine), CNS depressants (for example, ethanol), psychostimulants (for example, cocaine) and nicotine; complications of type I diabetes, renal dysfunction, liver dysfunction (for example, hepatitis, cirrhosis), gastrointestinal dysfunction (for example, diarrhea), colon cancer, overactive bladder and urinary incontinence. Depression and alcoholism could also potentially be treated with the compounds of the present invention.

Inflammation and inflammatory conditions associated with such inflammation include skin conditions (for example, sunburn, burns, eczema, dermatitis, allergic dermatitis, psoriasis), meningitis, ophthalmic diseases, such as glaucoma, retinitis, retinopathy, uveitis, and acute eye tissue lesions (e.g. conjunctivitis), inflammatory pulmonary disorders (eg, asthma, bronchitis, emphysema, allergic rhinitis, acute respiratory failure syndrome, poultry farmers' lung disease, farmer's lung, chronic obstructive pulmonary disease (COPD ), airway hyperreactivity); disorders of the gastrointestinal tract (for example, aphthous ulcer, Crohn's disease, atopic gastritis, varialoform gastritis, ulcerative colitis, celiac disease, regional ileitis, irritable bowel syndrome, inflammatory bowel disease, gastrointestinal reflux disease); Organ transplantation and other conditions with an inflammatory component, such as vascular disease, migraine, periarteritis nodosa, thyroiditis, aplastic anemia, Hodgkin's disease, sclerodoma, myasthenia gravis, multiple sclerosis, sorcoidosis, nephrotic syndrome, Bechet syndrome, gingivitis, ischemia of myocardium, pyrexia, systemic lupus erythematosus, polymyositis, tendinitis, bursitis and Sjogren's syndrome.

Immune diseases include autoimmune diseases, immune deficiency diseases or organ transplantation.

Bone diseases characterized by a metabolism or abnormal bone resorption include osteoporosis (especially postmenopausal osteoporosis), hypercalcemia, hyperparathyroidism, bone diseases of Paget, osteolysis, hypercalcemia of malignant tumors with or without bone metastases, rheumatoid arthritis, periodontitis, osteoarthritis osteopenia, cancer-associated cachexia, tuberculosis, lithiasis (especially urolithiasis), solid carcinoma, gout and ankylosing spondyloarthritis, tendinitis and bursitis. Cardiovascular diseases include hypertension or myocardial ischemia; atherosclerosis; functional or organic venous insufficiency; varicose treatment; Hemorrhoids and shock states associated with a marked decrease in blood pressure (for example, septic shock).

Neurodegenerative diseases include dementia, especially degenerative dementia (including senile dementia, dementia with Lewy bodies, Alzheimer's disease, Pick's disease, Huntingdon's chorea, Parkinson's disease and Creutzfeldt-Jakob syndrome, ALS, motor neuron disease) ; vascular dementia (including multi-infarct dementia); as well as dementia associated with lesions that occupy the intracranial space; trauma related infections and conditions (including HIV infection, meningitis and zoster); metabolism; toxins; anoxia and vitamin deficiency; and mild cognitive impairment associated with aging, particularly memory loss associated with age.

The compounds of formula (I) may also be useful in neuroprotection and in the treatment of neurodegeneration after trauma, such as stroke, cardiac arrest, pulmonary bypass, traumatic brain injury, spinal cord injury or the like.

The compounds of the present invention may also be useful in the treatment of malignant cell development and / or metastasis, and myoblastic leukemia.

Complications of type 1 diabetes include diabetic microangiopathy, diabetic retinopathy, diabetic nephropathy, macular degeneration, glaucoma, nephrotic syndrome, aplastic anemia, uveitis, Kawasaki disease and sarcoidosis.

Renal dysfunction includes nephritis, glomerulonephritis, particularly mesangial proliferative glomerulonephritis and nephritic syndrome.

It should be understood that the reference to treatment includes both the treatment of established symptoms and prophylactic treatment, unless explicitly stated otherwise.

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in human medicine.

or veterinary

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in the treatment of a condition mediated by P2X7 receptors.

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in the treatment of a human or animal subject suffering from a condition that is mediated by P2X7 receptors.

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in the treatment of a human or animal subject suffering from pain, inflammation or a neurodegenerative disease.

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in the treatment of a human or animal subject suffering from inflammatory pain, neuropathic pain or visceral pain.

According to another aspect of the invention, the inventors provide a compound of formula (I) or its pharmaceutically acceptable salt for use in the treatment of a human subject suffering from Alzheimer's disease.

According to another aspect of the invention, the inventors provide the use of a compound of formula (I) or its pharmaceutically acceptable salt for the manufacture of a medicament for the treatment of a condition that is mediated by the action of P2X7 receptors.

According to another aspect of the invention, the inventors provide the use of a compound of formula (I) or its pharmaceutically acceptable salt for the manufacture of a medicament for the treatment or prevention of pain, inflammation or a neurodegenerative disease.

According to another aspect of the invention, the inventors provide the use of a compound of formula (I) or its pharmaceutically acceptable salt for the manufacture of a medicament for the treatment or prevention of inflammatory pain, neuropathic pain or visceral pain.

In one aspect of the invention, the inventors provide the use of a compound of formula (I) or its pharmaceutically acceptable salt for the manufacture of a medicament for the treatment or prevention of Alzheimer's disease.

In order to use a compound of formula (I) or its pharmaceutically acceptable salt for the treatment of humans and other mammals, it is usually formulated in accordance with conventional pharmaceutical practice in the form of a pharmaceutical composition. Therefore, in another aspect of the invention there is provided a pharmaceutical composition comprising a compound of formula (I) or its pharmaceutically acceptable salt adapted for use in human or veterinary medicine.

To use the compounds of formula (I) in therapy, they will normally be formulated in a pharmaceutical composition according to conventional pharmaceutical practices. The present invention further provides a pharmaceutical composition, comprising a compound of formula (I) or its pharmaceutically acceptable salt, and optionally a pharmaceutically acceptable carrier.

A pharmaceutical composition of the invention, which can be prepared by mixing, suitably at room temperature and atmospheric pressure, is usually adapted for oral, parenteral or rectal administration and, for this, may be in the form of tablets, capsules, preparations oral liquids, powders, granules, lozenges, reconstitutable powders, injectable or infusible solutions or suspensions or suppositories. Orally administrable compositions are generally preferred.

Tablets and capsules for oral administration may be in a unit dose form, and may contain conventional excipients, such as binding agents, fillers, lubricants for tablet formation, disintegrants and acceptable wetting agents. The tablets may be coated according to methods well known in classical pharmaceutical practice.

Oral liquid preparations may be, for example, in the form of aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or they may be in the form of a dry product that will be reconstituted with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives, such as suspending agents, emulsifying agents, non-aqueous vehicles (which may include edible oils), preservatives, and, if desired, conventional flavoring and coloring.

For parenteral administration, fluid unit dosage forms are prepared using a compound of the invention or its pharmaceutically acceptable salt, and a sterile vehicle. The compound, depending on the vehicle and concentration used, may be suspended or dissolved in the vehicle. In the preparation of solutions, the compound can be dissolved for injection and sterilized by filtration before loading it into a suitable vial or vial and sealing it. Advantageously, adjuvants, such as local anesthetics, preservatives and buffering agents, are dissolved in the vehicle. To improve stability, the composition can be frozen after being introduced into the vial, and the water can be removed under vacuum. Parenteral suspensions are prepared essentially in the same way, except that the compound is suspended in the vehicle instead of dissolving it, and sterilization cannot be carried out by filtration. The compound can be sterilized by exposure to ethylene oxide before suspension in a sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the compound.

The composition may contain from 0.1% to 99% by weight, preferably from 10% to 60% by weight, of the active material, depending on the method of administration.

The dose of the compound used in the treatment of the aforementioned disorders will vary routinely according to the severity of the disorders, the weight of the patient and other similar factors. However, as a general rule, suitable unit doses may be 0.05 to 1,000 mg, more preferably 0.05 to 200 mg, for example 20 to 40 mg; and said unit doses will preferably be administered once a day, although administration may be needed more than once a day; and said therapy can be prolonged for several weeks or several months.

The following descriptions and examples illustrate the preparation of compounds of the invention. Examples:

The general methods (a) - (c), together with the synthetic methods outlined in Schemes 1-3 above, for the preparation of the compounds of the present invention, are further illustrated in the following examples. Example 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- [3-methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] acetamide (E1)

image3

[3-Methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] acetic acid (0.173 g, 0.43 mmol, prepared as described below) was dissolved in a mixture of dimethylformamide (1 ml) and dichloromethane (3 ml), carbodiimide was added to this

Water soluble (0.099 g, 0.52 mmol), 1-hydroxybenzotriazole (0.070 g, 0.52 mmol), and Netylmorpholine (0.164 ml, 1.29 mmol). The mixture was stirred for 10 minutes and then [(2-chloro-4-fluorophenyl) methyl] amine (0.082 g, 0.52 mmol) was added. The mixture was stirred overnight at room temperature and then saturated aqueous sodium bicarbonate (2 ml) was added to the mixture. After stirring for 10 more, the phase was separated

Organic by filtration through a hydrophobic frit. The aqueous layer was washed with another aliquot of dichloromethane (2-3 ml) and the organic phase was separated again, and then the combined organic phases were evaporated to yield the crude product as a yellow oil. The crude material was purified by a mass directed automatic HPLC to produce the pure product as a solid.

20 blank after lyophilization of the collected product fractions (0.080 g). LC / MS [M + H] + = 338, retention time = 2.32 minutes. The [3-methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] acetic acid used in the above procedure was obtained by hydrolysis of the corresponding ester ([3-methyl-5- (2-methylpropyl) -1H -pyrazol-4-yl] ethyl acetate). [3-methyl-5- (2-methylpropyl) -1H-pyrazole-4

Ethyl] ethyl acetate, in turn, was prepared by reacting ethyl 3-acetyl-6-methyl-4oxoheptanoate (see preparative details below) with hydrazine hydrate. Appropriate methodologies for preparing these or other analogous compounds have been previously described (for example, US 4,146,721). Ethyl 3-acetyl-6-methyl-4-oxoheptanoate was prepared as follows.

30 6-Methyl-2,4-heptandione (0.711 g, 5.0 mmol) was dissolved in dioxane (2 ml) and water (1

ml), and then cooled to 0 ° C. To this a solution of potassium hydroxide (0.281 g, 5.0 mmol) in water (2 ml) was added dropwise. The mixture was then heated to room temperature and stirred for 15 minutes. A solution of ethyl bromoacetate (0.554 ml, 5.0 mmol) in dioxane (1 ml) was added dropwise and the mixture was stirred overnight at room temperature. The organic phase was separated and the aqueous phase was then extracted with ethyl acetate (2 x 10 ml). The combined organic fractions were dried over anhydrous sodium sulfate and then filtered and evaporated to provide a pale yellow oil. This material was purified by silica column chromatography resolution

Automatic rapid (Biotage SP4 ™), eluting with a gradient of 020% ethyl acetate in hexane, to produce the [3-methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] ethyl acetate (0.333 g) as a colorless oil. Examples 2-3 In a manner analogous to that described for example 1 above, they were prepared

The compounds tabulated below (Table 1) replacing the 6-methyl-2,4-heptandione used in the above procedure with the appropriate diketones. All the diketones required to prepare the examples are shown in Table 1 are available from commercial sources or can be prepared using the routes previously described in the chemical literature.

twenty

Table 1 Example 4 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-dimethylethyl-1H-pyrazol-4-yl) acetamide (E4)

Example No.

Chemical name [M + H] + Retention time (min)

E2

N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3-methyl-5-phenyl1H-pyrazol-4-yl) acetamide 358 2.56

E3

338 2.32

N - [(2-Chloro-4-fluorophenyl) methyl] -2- [5- (1,1

dimethyl ethyl) -3-methyl-1H-pyrazol-4-yl] acetamide

image3

5 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide was prepared by a method analogous to that described for the preparation of N- [(2-Chloro-4-fluorophenyl) methyl] -2- [3-methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] acetamide (E1) but using (3,5-dimethyl-1H- acid) pyrazol-4-yl) acetic instead of [3-methyl-5- (2-methylpropyl) -1H-pyrazol-4-yl] acetic acid.

10 LC / MS [M + H] + = 296, retention time = 1.83 minutes. Examples 5-29 In a manner analogous to that described for example 4 above, the compounds tabulated below were prepared (Table 2) by replacing the [(2-chloro-4-fluorophenyl) methyl] amine used in the above procedure with the amines

15 appropriate. All the amines required to prepare the examples are shown in Table 2 are available from commercial sources or can be prepared using the routes previously described in the chemical literature.

Table 2

Example No.

Chemical name [M + H] + Holding time

(min)

Example No.

Chemical name [M + H] + Retention time (min)

E5

2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - [(2,3,4trifluorophenyl) methyl] acetamide 298 1.90

E6

N - [(2-bromophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 322 1.91

E7

N - [(4-chlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 278 1.93

E8

N - [(2,4-dichlorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 312 2.12

E9

N - [(3,4-dichlorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 312 2.13

Example No.

Chemical name [M + H] + Retention time (min)

E10

N - [(3,5-dichlorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 312 2.14

E11

N - [(2,6-dichlorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 312 1.95

E12

N - [(2-Chloro-6-methylphenyl) methyl] -2- (3,5-dimethyl-1Hpyrazol-4-yl) acetamide 292 1.99

E13

N - [(3-chlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 278 1.91

E14

N - [(2-Chloro-5-fluorophenyl) methyl] -2- (3,5-dimethyl-1Hpyrazol-4-yl) acetamide 297 1.85

Example No.

Chemical name [M + H] + Retention time (min)

E15

N - [(3-Chloro-2-methylphenyl) methyl] -2- (3,5-dimethyl-1Hpyrazol-4-yl) acetamide 292 2.10

E16

N - [(2-Chloro-6-fluorophenyl) methyl] -2- (3,5-dimethyl-1Hpyrazol-4-yl) acetamide 296 1.82

E17

N - [(2,5-dichlorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 312 2.01

E18

N - [(2-chlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 278 1.87

E19

N - [(2,4-difluorophenyl) methyl] -2- (3,5-dimethyl-1-pyrazol-4-yl) acetamide 280 1.75

Example No.

Chemical name [M + H] + Retention time (min)

E20

2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - {[4-fluoro-3 (trifluoromethyl) phenyl] methyl} acetamide 330 2.14

E21

2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - {[4-fluoro-2 (trifluoromethyl) phenyl] methyl} acetamide 330 2.03

E22

N - {[4-chloro-3- (trifluoromethyl) phenyl] methyl} -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 346 2.33

E23

N - [(2,4-dimethylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol 4-yl) acetamide 272 1.99

E24

N - {[2-Chloro-3- (trifluoromethyl) phenyl] methyl} -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 346 2.24

Example No.

Chemical name [M + H] + Retention time (min)

E25

N - [(2-Chloro-6-fluoro-3-methylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 310 2.00

E26

N - [(4-Bromo-2-fluorophenyl) methyl] -2- (3,5-dimethyl-1Hyrazol-4-yl) acetamide 340/342 2.02

E27

N - [(6-Chloro-2-fluoro-3-methylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide 310 2.04

E28

2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - [(2methylphenyl) methyl] acetamide 258 1.79

E29

2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - {[4 (trifluoromethyl) phenyl] methyl} acetamide 312 2.07

Example 30 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-diethyl-1 H -pyrazol-4-yl) acetamide (E30)

image3

The (3,5-diethyl-1 H -pyrazol-4-yl) acetic acid (0.260 g, approximately 1 mmol), prepared as described below) was dissolved in a mixture of dimethylformamide (0.5 ml) and dichloromethane (5 ml), and water soluble carbodiimide (0.230 g, 1.2 mmol), 1-hydroxybenzotriazole (0.162 g, 1.2 mmol) and N-ethylmorpholine (0.458 ml, 3.6 mmol) were added . The mixture was stirred for 10 minutes and then [(2-chloro-4-fluorophenyl) methyl] amine (0.239 g, 1.5 mmol) was added. The mixture was stirred for approximately 22 h at room temperature and then saturated aqueous sodium bicarbonate (3 ml) was added to the mixture. After stirring for a further 10, the organic phase was separated by filtration through a hydrophobic frit. The aqueous layer was washed with another aliquot of dichloromethane (approximately 1 ml) and the organic phase again separated, and then the combined organic phases were evaporated to yield the crude product as an orange oil. Raw material

15 was purified by an automatic mass directed HPLC to produce the pure product as an off-white solid after lyophilization of the collected product fractions (0.049 g). LC / MS [M + H] + = 324, retention time = 2.08 minutes.

The (3,5-diethyl-1H-pyrazol-4-yl) acetic acid used in the above method was prepared as follows:

(i) 3,5-Heptandione (2.03 ml, 15.0 mmol) was dissolved in dimethylformamide (10 ml) and cooled to 0 ° C using an ice bath. Then sodium hydride (60% in oil, 0.630 g, 15.75 mmol) was added slowly in portions and then the mixture was allowed to warm to room temperature and stirred for

25 approximately 30 minutes. The mixture was then treated with t-butyl bromoacetate (2.21 ml, 15.0 mmol) and stirred overnight (approximately 18 h) at room temperature. The mixture was concentrated, azeotropically evaporated with toluene to remove as much dimethylformamide as possible, and the residue was partitioned between water (approximately 20 ml) and ethyl acetate (approximately 20 ml). The layer

The organic was separated and the aqueous phase was acidified to approximately pH 5 using 2N aqueous hydrogen chloride and then extracted with ethyl acetate (2 x 20 ml). The combined organic extracts were dried over sodium sulfate, filtered and concentrated to produce a yellow oil. The oil was purified by flash chromatography on a silica gel column.

5 (Biotage SP4 ™), eluting with a gradient of 0-10% ethyl acetate in hexane, to produce pure 1,1-dimethylethyl 4-oxo-3-propanoylhexanoate (2.15 g) as an oil yellow.

(ii) 1,1-Dimethylethyl 4-oxo-3-propanoylhexanoate (1.08 g, 4.46 mmol) was dissolved in ethanol (15 ml), and treated with hydrazine hydrate (0.857 ml, 17.66 mmol). The mixture was heated at reflux at 95 ° C for 6 h, then cooled to room temperature and allowed to stand for a weekend. Most of the ethanol was removed in vacuo and the remaining residue was partitioned between dichloromethane (10 ml) and water (5 ml). The organic layer was separated using a hydrophobic frit and the aqueous layer was further extracted dichloromethane (2 x 10 ml). Organic extracts

15 assembled were concentrated to produce 1,1-dimethyl ethyl acetate (3,5-diethyl-1H-pyrazol-4-yl) as a pale yellow oil which was used in the next step without further purification.

(iii) 1,1-Dimethyl ethyl acetate (3,5-diethyl-1 H -pyrazol-4-yl) acetate (1.07 g, 4.49 mmol) was dissolved in dichloromethane (approximately 2 ml) and treated with acid trifluoroacetic

20 (2 ml). The mixture was stirred at room temperature for 3.5 h and then evaporated in vacuo, azeotropically evaporating with toluene to remove traces of trifluoroacetic acid, to produce (3,5-diethyl-1 H -pyrazol-4-yl) acetic acid. crude (1.52 g) as a brown / dark orange oil that was used without further purification. Example 31 2- (3,5-diethyl-1H-pyrazol-4-yl) -N - [(2,3,4-trifluorophenyl) methyl] acetamide (E31)

image3

25

2- (3,5-Diethyl-1H-pyrazol-4-yl) -N - [(2,3,4-trifluorophenyl) methyl] acetamide was prepared in a manner analogous to that described for the synthesis of N- [ (2-Chloro-4-fluorophenyl) methyl] 2- (3,5-diethyl-1H-pyrazol-4-yl) acetamide (example 30) above, but using [(2,3,4trifluorophenyl) methyl] amine instead of [(2-chloro-4-fluorophenyl) methyl] amine.

30 LC / MS [M + H] + = 326, retention time = 2.04 minutes.

Example 32 2- [3,5-bis (1-methylethyl) -1H-pyrazol-4-yl] -N - [(2-chloro-4fluorophenyl) methyl] acetamide (E32)

image3

2- [3,5-bis (1-Methylethyl) -1H-pyrazol-4-yl] -N - [(2-chloro-4)

5-fluorophenyl) methyl] acetamide in a manner analogous to that described for the synthesis of N [(2-chloro-4-fluorophenyl) methyl] -2- (3,5-diethyl-1 H -pyrazol-4-yl) acetamide ( Example 30) above, but using 2,6-dimethyl-3,5-heptandione instead of 3,5-heptandione. LC / MS [M + H] + = 352, retention time = 2.35 minutes. Example 33 2- [3,5-bis (1-methylethyl) -1H-pyrazol-4-yl] -N - [(2,3,4-trifluorophenyl) methyl] acetamide

10 (E33)

image3

2- [3,5-bis (1-Methylethyl) -1H-pyrazol-4-yl] -N - [(2,3,4trifluorophenyl) methyl] acetamide was prepared in a manner analogous to that described for the synthesis of N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-diethyl-1H-pyrazol-4-yl) acetamide (example 30)

15 above, but using 2,6-dimethyl-3,5-heptandione instead of 3,5-heptandione, and using [(2,3,4-trifluorophenyl) methyl] amine instead of [(2-chloro-4fluorophenyl) ) methyl] amine. LC / MS [M + H] + = 354, retention time = 2.31 minutes. Example 34 N - [(2-Chloro-4-fluorophenyl) methyl] -2- [3-methyl-5- (trifluoromethyl) -1H-pyrazole-4

20 il] acetamide (E34)

image3

A mixture of the crude [3-methyl-5- (trifluoromethyl) -1 H -pyrazol-4-yl] acetic acid (0.187 g, 0.9 mmol, prepared as described below) in dichloromethane (10 ml) was treated with 1-hydroxybenzotriazole hydrate (0.149 g, 1.1 mmol), N (3-dimethylaminopropyl) -N'-ethylcarbodiimide hydrochloride (0.211 g, 1.1 mmol) and N-ethylmorpholine (0.35 ml, 2.7 mmol), and the reaction was stirred at room temperature for 15 minutes. [(2-Chloro-4-fluorophenyl) methyl] amine (0.128 g, 0.8 mmol) was added, and the reaction mixture was stirred at room temperature for 16 hours. The mixture was diluted with dichloromethane, and the organic solution was washed sequentially with saturated aqueous sodium bicarbonate, water, citric acid, water and brine, dried and evaporated. The residue was purified by a mass directed automatic HPLC, and the resulting solid was triturated with ether / hexane, collected and dried to yield N - [(2-chloro-4-fluorophenyl) methyl] -2- [3-methyl- 5- (trifluoromethyl) -1 H -pyrazol-4-yl] acetamide (E34) LC / MS [M + H] + = 350, retention time = 2.46 minutes.

The 3-methyl-5- (trifluoromethyl) -1 H -pyrazol-4-yl] acetic acid used in the above procedure was prepared as follows:

(i)

A solution of 4-bromo-3-methyl-5- (trifluoromethyl) -1H-pyrazole (11.45 g, 50 mmol) in tetrahydrofuran (250 ml) was stirred at 5 ° C under an argon atmosphere. Sodium hydride (60% dispersion in oil, 2.0 g, 50 mmol) was added discontinuously, and the reaction mixture was stirred at 5 ° C for 10 minutes. {2 - [(Chloromethyl) oxy] ethyl} - (trimethyl) silane chloride (8.33 g, 8.9 ml, 50 mmol) was added dropwise, and the reaction was stirred at 5 ° C for 90 minutes. The reaction was quenched by the careful addition of water, and the mixture was extracted with ethyl acetate. The ethyl acetate extracts were combined, washed with water and brine, and then dried and evaporated. The residue was purified by column chromatography on silica gel, eluting with ethyl acetate / hexanes (1: 20-1: 10) to yield a mixture of 4-bromo-5-methyl-3- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazol and 4-bromo-3-methyl-5- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H -pyrazole (13.55 g) that was used in the next stage.

(ii)

A solution of 4-bromo-5-methyl-3- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazole and 4-bromo-3-methyl-5- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazole (10 g, 28 mmol) in tetrahydrofuran (150 ml) was stirred at -78 ° C under an argon atmosphere. N-Butyllithium (11.2 ml, 2.5 M solution in hexanes, 28 mmol) was added and the reaction was stirred at -78 ° C for 30 minutes. N, N-dimethylformamide (4.1 g, 4.3 ml, 56 mmol) was added dropwise and the reaction was stirred at -78 ° C for 30 minutes, and then heated to temperature

ambient and stirred at room temperature for 1 hour. The reaction mixture was cooled to 0 ° C and the reaction was quenched with a citric acid solution. The solution was extracted with ethyl acetate, the organic layer was separated, washed with water and brine, and then dried and evaporated to yield a mixture of 5-methyl-3- (trifluoromethyl) -1 - ({[2- ( trimethylsilyl) ethyl] oxy} methyl) -1 H -pyrazol-4-carbaldehyde and 3-methyl-5- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1 H -pyrazol-4-carbaldehyde ( 8.34 g) which was used in the next stage.

(iii) A solution of 5-methyl-3- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) 1H-pyrazol-4-carbaldehyde and 3-methyl-5- (trifluoromethyl) - 1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1Hyrazol-4-carbaldehyde (11.4 g, 37 mmol) in ethanol (100 ml) was stirred at room temperature. Sodium borohydride (0.700 g, 18.5 mmol) was added discontinuously with cooling in ice water. The suspension was stirred at room temperature for 30 minutes and then cooled in an ice-water bath and quenched by the careful addition of a citric acid solution. Ethyl acetate was added and the mixture was stirred at room temperature for 5 minutes and the organic solvent was evaporated. The resulting solution was extracted with ethyl acetate, and the organic layer was separated, washed with brine, dried and evaporated. The residue was purified by chromatography on silica gel, eluting with ethyl acetate / n-hexanes (1: 4-1: 1) to yield a mixture of [5-methyl-3- (trifluoromethyl) -1 - ({ [2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazol-4-yl] methanol and [3-methyl-5- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H -pyrazol-4-yl] methanol (7.7 g).

(iv)

A solution of [5-methyl-3- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) 1H-pyrazol-4-yl] methanol and [3-methyl-5- (trifluoromethyl) ) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1Hpyrazol-4-yl] methanol (3.1 g, 10 mmol) in dichloromethane (50 ml) was stirred at 5 ° C under an atmosphere of argon. Triethylamine (2.02 g, 2.8 ml, 20 mmol) was added, followed by methanesulfonyl chloride (1.37 g, 0.9 ml, 12 mmol) and the reaction was stirred at 5 ° C for 4 hours. The solution was washed with water, and the organic layer was separated, then washed sequentially with citric acid, water and brine. The solution was dried over anhydrous magnesium sulfate, then filtered and evaporated to yield a mixture of 4- (chloromethyl) -5-methyl-3- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy } methyl) 1H-pyrazole and 4- (chloromethyl) -3-methyl-5- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1Hpirazole (3.3 g) that was used In the next stage.

(v)

A solution of 4- (chloromethyl) -5-methyl-3- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazole and 4- (chloromethyl) -3-methyl-5 - (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1H-pyrazole (3.3 g, 10 mmol) in dimethylsulfoxide (20 ml) was treated

with potassium cyanide (0.650 g, 10 mmol) and the mixture was heated at 80 ° C for 5 hours. The reaction was cooled to room temperature, diluted with water and the solution was extracted with chloroform. The organic extracts were combined, then washed with water and then with brine, dried and evaporated. The residue was purified by silica gel chromatography, eluting with ethyl acetate / hexane (1: 10-1: 2) to yield a mixture of [5-methyl-3- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1 H -pyrazol-4-yl] acetonitrile and [3-methyl-5- (trifluoromethyl) -1 - ({[2 (trimethylsilyl) ethyl] oxy} methyl) -1 H -pyrazol -4-yl] acetonitrile (0.597 g) that was used in the next step.

(saw)

A mixture of [5-methyl-3- (trifluoromethyl) -1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1Hpyrazol-4-yl] acetonitrile and [3-methyl-5- (trifluoromethyl) - 1 - ({[2- (trimethylsilyl) ethyl] oxy} methyl) -1Hpyrazol-4-yl] acetonitrile (0.597 g, 1.9 mmol) in dioxane (4 ml) and hydrochloric acid (5 N, 4 ml) is heated to reflux for 24 hours. More hydrochloric acid (5 N, 2 ml) was added and the reaction was heated at reflux for a further 6 hours. After cooling to room temperature, the solvent was evaporated and the residue was coevaporated with toluene and ether. The residue was dried to produce the crude 3-methyl-5- (trifluoromethyl) -1 H -pyrazol-4-yl] acetic acid that was used in subsequent reactions without further purification. Examples 35-36

In a manner analogous to that described for example 34 above, the compounds tabulated below (Table 3) were prepared by replacing the [(2-chloro-4-fluorophenyl) methyl] amine used in the above procedure with the appropriate amine (or its salt). ). All the amines required to prepare the examples are shown in Table 3 are available from commercial sources or can be prepared using the routes previously described in the chemical literature, unless otherwise indicated.

Table 3 Example 37 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N- [1,2,3,4-tetrahydro-1-naphthalenyl] acetamide (E37)

Example No.

Chemical name [M + H] + Holding time

(min)

Example No.

Chemical name [M + H] + Retention time (min)

E35

N - [(2-Chloro-3,4-difluorophenyl) methyl] -2- [3-methyl-5 (trifluoromethyl) -1H-pyrazol-4-yl] acetamide 368 2.52

E36

N - {[2-Chloro-3- (trifluoromethyl) phenyl] methyl} -2- [3-methyl5- (trifluoromethyl) -1H-pyrazol-4-yl] acetamide 400 2.71

image3

5 (3,5-Dimethyl-1 H -pyrazol-4-yl) acetic acid (0.100 g, 0.35 mmol) was dissolved in dichloromethane (10 mL) and water soluble carbodiimide (0.162 g, 0 was added to this , 84 mmol), 1-hydroxybenzotriazole (0.114 g, 0.84 mmol), N-ethylmorpholine (0.413 ml, 3.25 mmol), and (1 S) -1,2,3,4-tetrahydro-1-naphthalethylamine ( 0.124 g, 0.52 mmol). The mixture was stirred overnight at room temperature and then diluted with more

10 dichloromethane (10 ml) and washed with saturated aqueous sodium bicarbonate (20 ml). The organic phase was separated by filtration through a hydrophobic frit and evaporated to yield the crude product as a yellow solid. The crude material was purified by mass directed automatic HPLC to produce pure 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N- [1,2,3,4-tetrahydro-1-naphthalenyl] acetamide as a white solid after

15 of lyophilization of the product fractions collected (0.029 g).

LC / MS [M + H] + = 284, retention time = 2.00 minutes.

Automatic mass directed HPLC Purification by automatic mass directed HPLC was performed

using the following devices and conditions:

Hardware

Waters 2525 binary gradient module

Waters 515 prep pump

Waters pump control module

Injection manifold Waters 2767

Waters column fluid conductor

Waters 2996 Photodiode Series Detector

Waters ZQ mass spectrometer

Gilson 202 fraction collector

Gilson Aspec waste collector

software

Waters Masslynx version 4 SP2

Column The columns used are Waters Atlantis, whose dimensions are 19 mm x

100 mm (small scale) and 30 mm x 100 mm (large scale). Particle size

of the stationary phase is 5 µm.

Solvents

A: aqueous solvent = water + 0.1% formic acid

B: organic solvent = acetonitrile + 0.1% formic acid Preparation solvent = methanol: water 80:20 Needle rinse solvent = methanol Methods

Five methods are used depending on the analytical retention time of the compound of interest. All have a runtime of 13.5 minutes, which comprises a 10 minute gradient followed by a generous 3.5 minute column wash and a rebalancing stage. Large / small scale 1.0-1.5 = 5-30% of B Large / small scale 1.5-2.2 = 15-55% of B Large / small scale 2.2-2.9 = 30- 85% of B Large / small scale 2.9-3.6 = 50-99% of B Large / small scale 3.6-5.0 = 80-99% of B (in 6 minutes followed by abundant washing of 7 , 5 minutes and rebalanced) Flow

All of the above methods have a flow rate of 20 ml / min (small scale) 5 or 40 ml / min (large scale) Liquid chromatography / Mass spectrometry

The analysis of the previous examples by liquid chromatography / mass spectrometry (LC / MS) was carried out using the following apparatus and conditions: Hardware

10 Agilent 1100 Gradient Pump Agilent 1100 Auto-Injector Agilent 1100 DAD Detector Agilent 1100 Degasser Agilent 1100 Stove

15 Agilent 1100 Controller Waters Mass Spectrometer ZQ Sedere Sedex 85 Waters Masslynx Software version 4.0 SP2

20 column

The column used is a Waters Atlantis, whose dimensions are 4.6 mm x 50 mm. The particle size of the stationary phase is 3 µm. Solvents

A: Aqueous solvent = water + 0.05% formic acid 25 B: Organic solvent = acetonitrile + 0.05% formic acid

Method The generic method used has a runtime of 5 minutes.

Time / min

% of B

0

3

0.1

3

4

97

4.8

97

4.9

3

5.0

3

The previous method has a flow rate of 3 ml / min The injection volume for the generic method is 5 ul. The temperature of the column is 30 degrees. The UV detection range is 220 to 330 nm. Pharmacological data

The compounds of the invention can be tested for in vitro biological activity at the P2X7 receptor according to the following studies: Ethidium Accumulation Assay

The studies were performed using a NaCl assay buffer with the following composition (in mM): NaCl 140, HEPES 10, N-methyl-D-glucamine 5, KCl 5.6, D-glucose 10, CaCl2 0.5 ( pH 7.4). HEK293 cells, expressing recombinant human P2X7 receptors, were cultured in 96-well plates pretreated with poly-L-lysine for 18-24 h (cloning of the human P2X7 receptor is described in US 6,133,434). The cells were washed twice with 350 µl of assay buffer before the addition of 50 µl of the test compound. The cells were then incubated at room temperature (19-21 ° C) for 30 min before the addition of ATP and ethidium (100 µM final test concentration). The ATP concentration was selected close to CE80 for the type of receptor and was 1 mM for studies on the human P2X7 receptor. Incubations continued for 8 or 16 min and ended with the addition of 25 µl of 1.3 M sucrose containing 5 mM of the P2X7 receptor antagonist black reagent 5 (Aldrich). The cellular accumulation of ethidium was determined by measuring the fluorescence (excitation wavelength of 530 nm and emission wavelength of 620 nm) from below the plate with a Canberra Packard Fluorocount (Pangbourne, United Kingdom) or a Flexstation.II (Molecular Devices). The pCI50 values of the antagonists to block ATP responses were determined using iterative curve fitting techniques. Ca test of fluorescent imaging plate reader (FLIPR)

The studies were performed using a NaCl assay buffer with the following composition (in mM) for human P2X7: NaCl 137; HEPES 20; KCI; 5.37; NaHCO3 4.17; CaCl2 1; MgSO4 0.5; and 1g / l of D-glucose (pH 7.4). HEK293 cells, expressing recombinant human P2X7 receptors, were cultured in 384-well plates pretreated with poly-L-lysine for 42-48 h (cloning of the human P2X7 receptor is described in US 6,133,434). The cells were washed three times with 80 µl of assay buffer, loaded for 1 h at 37 ° C with Fluo4 2

µM (Teflabs), washed three times again and left with 30 µl of buffer before adding 10 µl of 4x of the concentrated test compound. The cells were then incubated at room temperature for 30 min before the addition (online, by means of a FLIPR384 or FLIPR3 (Molecular Devices)) instrument of benzoylbenzoyl5 ATP (BzATP), final assay concentration 60 µM. The concentration of BzATP was chosen close to CE80 for the type of receptor. Incubations and readings continued for 90 seconds, and the increase in intracellular calcium was determined by measuring the fluorescence (excitation wavelength of 488 nm and emission wavelength of 516 nm) below the plate, with a FLIPR camera CCD The

10 pCI50 values of the antagonists to block BzATP responses were determined using iterative curve fitting techniques.

The compounds of examples 1-37 were tested in the Ca FLIPR assay and / or in the ethidium accumulation assay for the activity of the human P2X7 receptor antagonist and were found to have pCI50 values> 4.7 in the assay. from

15 Ca FLIPR and / or pCI50 values> 5.5 in the ethidium accumulation test.

Claims (3)

1. A compound of formula (I) or its pharmaceutically acceptable salt: image 1 in which: R1 and R2 represent C1-6 alkyl, phenyl, or C3-6 cycloalkyl, any one being optionally substituted with 1, 2 or 3 halogen atoms; R3 and R4 independently represent hydrogen or C1-3 alkyl; R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl, and any of Said C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-6 cycloalkyl or phenyl optionally is substituted with 1, 2 or 3 halogen atoms; or R8 and R9, together with the carbon atoms to which they are attached, form a benzene ring that is optionally substituted with 1, 2 or 3 halogen atoms; or R4 and R5, together with the carbon atoms to which they are attached form a C5-7 cycloalkyl; with the proviso that when R5 and R9 are both selected from hydrogen or fluorine, at least one of R6, R7 and R8 is a halogen atom, or R6, R7 and R8 are selected from the group consisting of hydrogen, methyl and CF3, and one, but not more than one of R6, R7 and R8 is methyl or CF3. 2. A compound of formula (I), or its pharmaceutically acceptable salt, according to claim 1, wherein R1 and R2 independently represent unsubstituted C1-6 alkyl, trifluoromethyl, phenyl or C3-6 cycloalkyl. 3. A compound of formula (I), or its pharmaceutically acceptable salt, according to claim 1 or 2, wherein R3 and R4 both represent hydrogen. 4. A compound of formula (I), or its pharmaceutically acceptable salt, according to any one of claims 1 to 3, wherein R5, R6, R7, R8 and R9 independently represent hydrogen, halogen, cyano, trifluoromethyl or methyl.  5. A compound of formula (I) according to claim 1, which is: N - [(2-chloro-4-fluorophenyl) methyl] -2- [3-methyl-5- (2-methylpropyl) -1H- pyrazol-4-yl] acetamide (E1) image 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3-methyl-5-phenyl-1H-pyrazol-4-yl) acetamide (E2) image 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- [5- (1,1-dimethylethyl) -3-methyl-1 H -pyrazol-4-yl] acetamide 5 (E3) image 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E4) image 1 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - [(2,3,4-trifluorophenyl) methyl] acetamide (E5) image2 N - [(2-bromophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E6) image 1 N - [(4-chlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E7) image 1 N - [(2,4-dichlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E8) image3 N - [(3,4-dichlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E9) image 1 N - [(3,5-dichlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E10) image 1 10 N - [(2,6-dichlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E11) image 1 N - [(2-Chloro-6-methylphenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E12) image 1 N - [(3-chlorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E13) image 1 N - [(2-Chloro-5-fluorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E14) image 1 N - [(3-Chloro-2-methylphenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E15) image 1 N - [(2-Chloro-6-fluorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E16) image2 N - [(2,5-dichlorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E17) image 1 N - [(2-chlorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E18) image 1 N - [(2,4-difluorophenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E19) image 1 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - {[4-fluoro-3- (trifluoromethyl) phenyl] methyl} acetamide (E20) image3 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - {[4-fluoro-2- (trifluoromethyl) phenyl] methyl} acetamide (E21) image 1 N - {[4-chloro-3- (trifluoromethyl) phenyl] methyl} -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E22) image 1 10 N - [(2,4-dimethylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E23) image 1 N - {[2-Chloro-3- (trifluoromethyl) phenyl] methyl} -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E24) image 1 N - [(2-Chloro-6-fluoro-3-methylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E25) image 1 N - [(4-Bromo-2-fluorophenyl) methyl] -2- (3,5-dimethyl-1H-pyrazol-4-yl) acetamide (E26) image3 N - [(6-Chloro-2-fluoro-3-methylphenyl) methyl] -2- (3,5-dimethyl-1 H -pyrazol-4-yl) acetamide (E27) image 1 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N - [(2-methylphenyl) methyl] acetamide (E28) image 1 10 2- (3,5-Dimethyl-1 H -pyrazol-4-yl) -N - {[4- (trifluoromethyl) phenyl] methyl} acetamide (E29) image 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- (3,5-diethyl-1H-pyrazol-4-yl) acetamide (E30) image 1 2- (3,5-diethyl-1H-pyrazol-4-yl) -N - [(2,3,4-trifluorophenyl) methyl] acetamide (E31) image 1 2- [3,5-bis (1-methylethyl) -1 H -pyrazol-4-yl] -N - [(2-chloro-4-fluorophenyl) methyl] acetamide (E32) image3 2- [3,5-bis (1-methyl ethyl) -1 H -pyrazol-4-yl] -N - [(2,3,4-trifluorophenyl) methyl] acetamide (E33) image 1 N - [(2-Chloro-4-fluorophenyl) methyl] -2- [3-methyl-5- (trifluoromethyl) -1H-pyrazol-4-yl] acetamide image4 N - [(2-Chloro-3,4-difluorophenyl) methyl] -2- [3-methyl-5- (trifluoromethyl) -1H-pyrazol-4-yl] acetamide (E35) image 1 N - {[2-Chloro-3- (trifluoromethyl) phenyl] methyl} -2- [3-methyl-5- (trifluoromethyl) -1H-pyrazol-4-yl] acetamide (E36) image 1 2- (3,5-dimethyl-1H-pyrazol-4-yl) -N- [1,2,3,4-tetrahydro-1-naphthalenyl] acetamide (E37) image 1 or its pharmaceutically acceptable salt. 6. A pharmaceutical composition comprising a compound of formula (I) or its pharmaceutically acceptable salt, according to any one of the preceding claims, and a pharmaceutically acceptable carrier or excipient. 7. A compound, or its pharmaceutically acceptable salt, according to any one of claims 1 to 5 for use in therapy. 8. A compound of formula (I) according to any one of claims 1 to 5 or its pharmaceutically acceptable salt for use in the treatment of a human or animal subject suffering from pain, inflammation or a neurodegenerative disease. 9. The use of a compound, or its pharmaceutically acceptable salt, according to any one of claims 1 to 5, for the manufacture of a medicament for the treatment of pain, inflammation or a neurodegenerative disease.