OA19480A

OA19480A - Pharmacologically active alicyclicsubstituted pyrazolo [1,5-a] pyrimidine derivatives.

Info

Publication number: OA19480A
Application number: OA1201900350
Authority: OA
Inventors: lstván BORZA; Viktor Román; Jânos ÉLES; Zsuzsa Hadady
Original assignee: Richter Gedeon Nyrt.
Priority date: 2017-03-13
Filing date: 2018-03-12
Publication date: 2020-10-23

Abstract

The present invention relates to new pyrazolo [l,5a] pyrimidine derivatives of formula (I) or pharmaceutically acceptable salts, biologically active metabolites, pro-drugs, racemates, enantiomers, diastereomers, solvates and hydrates thereof that serve as GABAb receptor positive allosteric modulators. The invention al so relates to the process for producing such compounds. The invention further relates to pharmaceutical compositions comprising such compounds optionally in combination with two or more different therapeutic agents and the use of such compounds in methods for treating diseases and conditions mediated and modulated by the GABAb receptor positive allosteric mechanism. The invention al so provides a method for manufacture of medicaments useful in the treatment of such disorders.

Description

The présent invention relates to the pyrazolo[l,5-a]pyrimidine dérivatives of formula (I)

(O

R¹ and R² are independently selected from hydrogen, halogen atom, Ci-6alkyl, haloCi-ealkyl;

R³ is hydrogen, halogen atom, Ci-6alkyl, cyano group;

R⁴ is Ci-6alkyl;

R⁵ is Ci-éalkyl optionally substituted by a halogen atom or halogen atoms, C3.5 cycloalkyl;

C3-5 cycloalkylCi-ealkyl, dialkylamino, Ci-ealkoxy, Ci.₆alkoxyCi.₆alkyl, Ci-ealkylthio group, tetrahydrofüranyl, tetrahydrofuranylCi-ôalkyl, tetrahydropyranyl, tetrahydropyranylCi-ealkyl; or R₄ and R5 together form an unsubstituted or substituted by one or more Ci-3alkyl, C 1.3alkoxy, haloCi-salkyl, Ci-3alkylcarbony] 3 to 7-membered saturated ring, wherein the members ofthe ring are selected from the group consisting of carbon, nitrogen, oxygen, and sulphur;

R⁶ is hydrogen, halogen atom or Ci-₆alkyl, hydroxyl, Ci-₆alkoxy, Ci^alkoxyCi^alkyl, haloCiealkyi, amino group;

or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof. The term “halogen” or “halo” as used herein alone or as a part of another group refers to chlorine, bromine, fluorine and iodine.

The term “Ci-Cô alkyl” as used herein refers to branched or straight chain alkyl groups comprising one to six carbon atoms, including but not limited to methyl, ethyl, propyl, normaland isopropyl and different butyl groups.

The term “C3-C5 cycloalkyl” as used herein refers to carbocyclic groups of 3 to 5 carbons, respectively; for example, cyclopropyl, cyclobutyl, and cyclopentyl.

The term “Ci-Cô alkoxy” as used herein refers to branched or straight chain alkyl groups comprising one to four carbon atoms bonded through an oxygen atom, including but not limited to, methoxy, ethoxy, n-propoxy, i-propoxy, and t-butoxy.

The term “Ci-6alkylthio” as used herein refers to branched or straight chain alkyl groups comprising one to six carbon atoms bonded through a sulphur atom, including but not limited to, methylthio, ethylthio, n-propylthio, i-propylthio, and t-butylthio.

The term “mammal” as used herein refers to any members of the class “Mammalia” including, but not limited to human.

The term “sait” means nontoxic base addition salts of the compounds of the invention which are generally prepared by reacting the acid with a suitable organic or inorganic base.

Included within the scope of the présent invention are ail stereoisomers, géométrie isomers and tautomeric forms of the compounds of formula (I), including compounds exhibiting more than one type of isomerism and mixtures of one or more thereof.

Conventional techniques for the preparation/isolaton of individual enantiomers include chiral synthesis from the suitable optically pure precursor or resolution of the racemate (or racemate of a sait or dérivative) using, for example chiral high pressure liquid chromatography (HPLC).

The term “pharmaceutically acceptable” describes an ingrédient that is useful in preparing a pharmaceutical composition and is generally safe, non-toxic and neither biologically nor otherwise undesirable, and includes those acceptable for veterinary use as well as human pharmaceutical use.

The term “pharmaceutical composition” refers to a mixture of a compound of the invention with other Chemical components, such as pharmaceutically acceptable auxiliary 5 materials, e.g. diluents or carriers. The pharmaceutical composition facilitâtes administration of the compound to the subject.

The term excipient defines a Chemical compound that facilitâtes the incorporation of a compound into cells or tissues.

As used herein, the term “treatment” means using an effective therapy to reduce, 10 alleviate or eliminate the symptoms associated with diseases and conditions mediated and modulated by the GABAb receptor positive allosteric mechanism.

As a fùrther aspect of the présent invention there is provided the synthesis of compounds of formula (I).

Compounds according to the présent invention were synthesized in line with the 15 synthetic routes and schemes described below.

Accordingly, the compounds of formula (I) of the invention can be synthesized by one of the following routes:

Route a):

(IX) (l)

Route c):

Route d):

Route e):

Step 1) Reacting a carboxylic acid ester dérivative of formula (II) or carboxylic acid chloride dérivative of formula (III)

(II)

(III) wherein the meaning of R¹ and R² is described above for compound of formula (I) with an acetonitrile dérivative of formula (IV)

R (IV)

- wherein the meaning of R³ is described above for compound of formula (I), then step 2) the so obtained acylacetonitrile dérivative of formula (V) is reacted with

2a) hydrazine hydrate to provide a compound of formula (VI)

- wherein the meaning of R¹, R² is as described above and R³ is hydrogen, halogen atom, Ci-6alkyl group or

2b) trimethyl orthoformate to provide the malononitrile dérivative of formula (XIV)

- wherein the meaning of R¹, R² is as described above and R³ is cyano group which is reacted with hydrazine hydrate to provide a compound of formula (VI) then step 3) the compound of formula (VI) wherein the meaning of R¹, R², R³ is as described above for the formula (I) - obtained according to the steps described in 2a) or 2b) is reacted with acylacetic ester dérivative of formula (VII)

Alk^ (VII)

- wherein the meaning of R⁴ and R³ is as described above for the formula (I), then step 4) the so obtained compound of formula (VIII)

OH (VIII)

- wherein the meaning of R¹, R², R³, R⁴,and R⁵ is as described above for the formula (I) -is chlorinated to furnish a chloro dérivative of formula (IX)

- wherein the meaning of R¹, R², R³, R⁴,and R⁵ is as described above for the formula (I) - and step 5) the latter is reacted with either

5c) a nipecotic acid dérivative of formula (X)

H (X)

- wherein the meaning of R⁶ is as described above for the formula (I) - and the obtained dérivative of formula (I) and optical antipodes or racemates and/or salts thereof in given case can be transformed into an other compound of formula (I) and optical antipodes or racemates and/or salts thereof by introducing new substituents and/or modifying or removing the existing ones, or

5d) its alkali sait of formula (XI)

(XI)

- wherein the meaning of R⁶ is as described above for the formula (I) - and the obtained compound of formula (I) and optical antipodes or racemates and/or salts thereof in given case can be transformed into an other compound of formula (I) and optical antipodes or racemates and/or salts thereof by introducing new substituents and/or modifying or removing the existing ones, or

5e) a nipecotic acid ester dérivative of formula (XII)

H (XII)

- wherein the meaning of R⁶ is as described above for the formula (I) - to provide the ester dérivative of formula (XIII)

wherein the meaning of R¹, R², R³, R⁴, R⁵ and R⁶ is as described above for the formula (I) finally the latter is saponified with a strong base or acid - and the obtained dérivative of formula (I) and optical antipodes or racemates and/or salts thereof optionally can be transformed into an other compound of formula (I) and optical antipodes or racemates and/or salts thereof by introducing new substituents and/or modifying or removing the existing ones.

The synthesis of acylacetonitrile dérivative (V) can be carried out by different routes:

Route a):

a) The reaction of a carboxylic acid ester dérivative of formula (II) with an acetonitrile dérivative of formula (IV) is preferably carried out in a proper solvent, e.g. tetrahydrofùran, preferably in the presence of a strong base e.g. n-butyllithium, lithium bis(trimethylsilyl)amide. The reaction carried out at a température in the range of -78 °C to room température. The necessary reaction time is 1-16 h. The reactions are followed by thin layer chromatography. The reaction is quenched by addition of water and hydrochloric acid (~pH 2-3) or saturated ammonium chloride solution. The product (V) is isolated by extraction with a proper organic solvent or by filtration, after removing the organic solvent.

b) The reaction of an carboxylic acid chloride dérivative of formula (III) with an acetonitrile dérivative of formula (IV) is preferably carried out in a proper solvent, e.g. tetrahydrofùran, preferably in the presence of a strong base e.g. n-butyllithium, lithium bis(trimethylsilyl)amide. The reaction carried out at a température in the range of -78 °C to room température. The necessary reaction time is 1-16 h. The reactions are followed by thin layer chromatography. The reaction is quenched by addition of water and hydrochloric acid (~pH 2-3) or saturated ammonium chloride solution. The product (V) is isolated by extraction with a suitable organic solvent or by filtration, after removing the organic solvent.

The cyclocondensation reaction of the acyl nitrile dérivatives of formula (V) with hydrazine hydrate to pyrazole dérivatives of formula (VI) is preferably carried out in a suitable solvent, e.g. éthanol. The reaction is preferably carried out at boiling point of the solvent. The necessary reaction time is 1-6 h. The reactions are followed by thin layer chromatography. The work-up of the reaction mixture can be carried out by the following routes:

a) The reaction mixture is diluted with water and the product is isolated by filtration or extraction with a suitable organic solvent and in given case purified by crystallization or column chromatography.

b) The reaction mixture is evaporated in vacuo and the crude product is used in the next step without further purification.

Route b):

The reaction of a carboxylic acid chloride dérivative of formula (III) with malononitrile is preferably carried out in a suitable solvent, e.g. tetrahydrofuran, preferably in the presence of a base e.g. triethylamin. The reaction carried out at a température in the range of 0 °C to room température. The necessary reaction time is 1-16 h. The reactions are followed by thin layer chromatography. The reaction is quenched by addition of water. The product (V) is isolated by extraction with a suitable organic solvent.

The O-methylation of the acyl malononitrile dérivative of formula (V) with trimethyl orthoformate is preferably carried out at boiling point. The necessary reaction time is 1-16 h. The reactions are followed by thin layer chromatography. The product (XIV) is purified by column chromatography.

The cyclocondensation reaction of the O-methylated acyl nitrile dérivatives of formula (XIV) with hydrazine hydrate to pyrazole dérivatives of formula (VI) is preferably carried out in a suitable solvent, e.g. éthanol. The reaction is preferably carried out at room température. The necessary reaction time is 1-6 h. The reactions are followed by thin layer chromatography. The reaction mixture is diluted with water and the product is isolated by extraction with a suitable organic solvent.

The cyclocondensation reaction of the l/7-pyrazol-5-amine dérivative of formula (VI) with an acylacetic ester dérivative of formula (VII) is preferably carried out in a suitable solvent,

e.g. toluene, by the addition of catalytic amount of p-toluenesulfonic acid, using a Dean- Stark water separator. The reaction is preferably carried out at boiling point of the solvent. The necessary reaction time is 1-16 h. The reactions are followed by thin layer chromatography.

The product (VIII) is isolated by filtration.

Chlorination of the pyrazolo[l,5-«]pyrimidme dérivative of formula (VIII) can be carried out in a suitable solvent, e.g. toluene using a suitable chlorinating agent, e.g. phosphorus oxychloride by the addition of triethylamine or Ν,Ν-diisopropylethylamine. The reaction is preferably carried out at boiling point of the solvent. The necessary reaction time is 24-48 h. The reactions are followed by thin layer chromatography. The reaction mixture is poured into sodium hydrogen carbonate solution and chrushed ice. The decomposed reaction mixture is filtered and the product is isolated from the filtrate by extraction with a suitable organic solvent and in given case purified by crystallization or column chromatography. The column chromatography is carried out on normal phase using Kieselgel 60 as adsorbent and different solvent Systems, e.g. n-hexane/ethyl acetate, toluene/methanol, chloroform/methanol or toluene/acetone, as eluents.

N-arylation reaction of the nipecotic acid dérivative of formula (X) or (XII) with the chloro denvative of formula (IX) carried out in a suitable solvent, e.g. dimethylformamide, dimethylsulfoxide, N-methyl-pyrrolidone. The reaction is preferably carried out between 80°C and 140 °C. A suitable amine of formula (X) or (XII) is added as base or as a sait formed with inorganic acid to the so obtained solution in the presence of a base, for example césium carbonate or Ν,Ν-diisopropylethylamine, needed for the libération of the amine or formed with inorganic base for example potassium sait of formula (XI). The reactions are followed by thin layer chromatography. The necessary reaction time is 3-20 h. The work-up of the reaction mixture can be carried out by different methods.

When the N-arylated product is an acid dérivative of formula (I) and the reaction mixture is a suspension, the inorganic sait is filtered off, the filtrate is diluted with water and acidified with acetic acid. The product is isolated by filtration or extraction with a suitable organic solvent and in given case purified by crystallization or column chromatography. If the reaction mixture is a solution, it is diluted with water and acidified with acetic acid. The product is isolated by filtration or extraction with a suitable organic solvent and in given case purified by crystallization or column chromatography.

When the N-arylated product is an ester dérivative of formula (XIII), the reaction mixture is evaporated in vacuo. The product is isolated by crystallization or extraction with a suitable organic solvent and in given case purified by recrystallization or column chromatography.

The hydrolysis of the carboxylic acid ester dérivative of formula (XIII) into the carboxylic acid dérivative of formula (I) can be carried out with an appropriate strong inorganic base, e.g. lithium hydroxide, sodium hydroxide or with an appropriate strong inorganic acid, e.g. hydrochloric acid. The reaction is preferably carried out between room température and 100 °C. The reactions are followed by thin layer chromatography. The necessary reaction time is 1-20 h. The reaction mixture is diluted with water and acidified with acetic acid. The product is isolated by filtration or extraction with a suitable organic solvent and in given case purified by crystallization or column chromatography. The structures of the products are determined by NMR. and mass spectrometry.

Most ofthe nipecotic acid dérivatives of formula (X) and (XII) are either commercially available or can be synthesized by different known methods. The synthèses of some new nipecotic acid dérivatives of formula (XII) are described in the Intermediates section.

The compounds of the présent invention and optical antipodes or racemates and/or salts thereof can be used as such or suitably in the form of pharmaceutical compositions.

The invention also relates to the pharmaceutical compositions containing the compounds of formula (I) or optical antipodes or racemates and/or salts thereof as active ingrédient for the treatment of certain disorders associated with GABAb receptor positive allosteric modulator activity.

The présent compounds may be coadminstered to a subject in combination with two or more different therapeutic agents (eg. most preferably antipsychotics and psychostimulants; and preferably antidepressants, anxiolytics, antihypertensives, anticonvulsants, sédatives, and narcotics).

Suitable routes of administration may, for example, include oral, rectal, transmucosal, transdermal or intestinal administration; parentéral delivery, including intramuscular, subcutaneous, intravenous, intramedullary injections, as well as intraarticular, intrathecal, direct intraventricular, intraperitoneal, intranasal, or intraocular injections and eye drops.

Alternatively, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly in the rénal or cardiac area, often in a depot or sustained release formulation. Furthermore, one may administer the drug in a targeted drug delivery System, for example, in a liposome coated with a tissue-specific antibody. The liposomes will be targeted to and taken up selectively by the organ.

The pharmaceutical compositions can be administered through via a variety of routes and dosages forms. The compound of the invention may be administered either alone or in combination with pharmaceutically acceptable carriers, in either single or multiple doses. The dosage required to exert the therapeutical effect can vary within wide limits and will be fitted to the individual requirements in each of the particular case, depending on the stage of the disease, the condition and the bodyweight of the patient to be treated, as well as the sensitivity of the patient against the active ingrédient, route of administration and number of daily treatments.

For the sake of a simple administration it is suitable if the pharmaceutical compositions comprise dosage units containing the amount of the active ingrédient to be administered once, or a few multiples or a half, third or fourth part thereof. Such dosage units are e.g. tablets, which can be powdered with grooves promoting the halving or quartering of the tablet in order to exactly administer the required amount of the active ingrédient.

The pharmaceutical compositions containing the active ingrédient according to the présent invention usually contain 0.01 to 500 mg of active ingrédient in a single dosage unit. It is, of course possible that the amount of the active ingrédient in some compositions exceeds the upper or lower limits defined above.

As a further aspect of the invention there is provided the pharmaceutical manufacture of médicaments containing the compounds of formula (I) or optical antipodes or racemates and/or salts thereof.

The pharmaceutical compositions of the présent invention may be formulated as different pharmaceutical dosage forms, such as but not limited to, solid oral dosage forms like tablets (e.g. buccal, sublingual, effervescents, chewable, orodispersible, freeze dried), capsules, lozenges, pastilles, pills, orodispersible films, granules, powders; liquid oral dosage forms like solutions, émulsions, suspensions, syrups, elixires, oral drops; parentéral dosage forms like intravenous injections, intramuscular injections, subcutaneous injections; other dosage forms like eye drops, semi-solid eye préparations, transdermal dosage forms, suppositories, rectal capsules, rectal solutions, émulsions and suspensions, etc.

In one embodiment the invention relates to pharmaceutical dosage forms specifically intended for pédiatrie use, such as but not limited to, solutions, syrups, élixirs, suspensions, powders for reconstitution as suspension, dispersible or effervescent tablets, chewable tablets, orally disintegrating tablets, tablets or coated tablets, sprinkle oral powder or granules, capsules.

The pharmaceutical compositions of the présent invention may be manufactured in a manner that is itself known, e.g., by means of conventional mixing, dissolving, emulsifying, suspending, entrapping, freeze-drying, extrusion, laminating, film-casting, granulating, grinding, encapsulating, dragee-making or tabletting processes.

Pharmaceutical compositions for use in accordance with the présent invention thus may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into préparations which can be used pharmaceutically. Proper formulation is dépendent upon the route of administration chosen. Any of the well-known techniques, carriers, and excipients may be used as suitable and as understood in the art.

Suitable excipients for the préparation of the dosage forms may be selected from the following categories, such as but not limited to, tablet and capsule fillers, tablet and capsule binders, modified-release agents, disintegrants, glidants, lubricants, sweetening agents, tastemasking agents, flavoring agents, coating agents, surfactants, antioxidants, buffering agents, complexing agents, emulsifying agents, lyophilization aids, microencapsulating agents, ointment bases, pénétration enhancers, solubilizing agents, solvents, suppository bases, suspending agents.

In one embodiment the invention relates to the using of spécifie excipients which are able to improve the solubility, dissolution, pénétration, adsorption or bioavailability of the active ingredient(s), such as but not limited to, hydrophilic polymers, hot melt extrusion excipients, surfactants, buffering agents, complexing agents, emulsifying agents, lyophilization aids, superdisintegrants, microencapsulating agents, pénétration enhancers, solubilizing agents, co-solvents, suspending agents.

The above described ingrédients and different routes of manufacture are merely représentative. Other materials as well as processing techniques and the like well known in the art can also be used.

The compounds are effective in the treatment of psychiatrie, neurodevelopmental, neurological and other central nervous system disorders as well as peripheral conditions where stimulation of the GAB Ab receptor may offer therapeutic benefit

BIOLOGICAL ACTIVITY

In vitro [³⁵S]GTPyS binding assay in rat cortical membranes

Cortices of freshly harvested rat brains were dissected on an ice-cold surface and homogenized by a glass Dounce homogeniser immediately in ice-cold buffer containing 50 mM Tris, 5 mM MgCh and 1 mM EDTA (pH=7.6). Tissue homogenates were centrifuged at 40000 g for 15 min at 4°C. Membane pellets were resuspended in the same buffer and membranes were incubated for 10 min at 30°C in a shaking water bath to eliminate endogenous GABA. Homogenates were centrifuged again under the same conditions. The final pellets were resuspended in ice-cold buffer (pH=7.6) containing 50 mM Tris, 100 mMNaCl, 7 mM MgCh, 1 mM EDTA and 1 mM dithiotreithol (DTT) to yield a concentration of 20 mg tissue weight/ml and frozen at -70°C until use. The assay was done in a buffer containing 50 mM Tris (pH=7.4), 100 mM NaCl, 7 mM MgCh, 1 mM EDTA and 1 mM DTT. Each assay tube contained 150 pL GDP (in a final concentration of 50 μΜ), 100 pL ligand and 125 pL of the membrane suspension (250 pg tissue/tube). The assay tubes were preincubated for 10 min at 30°C to assure equilibrium. Nonspecific binding was determined in the presence of 10 pM GTPyS; basal binding was determined in the presence of buffer only. After addition of 50 pM [³⁵S]GTPyS in a volume of 25 pL to the tubes, membranes were incubated for an additional 60 min at 30°C. The assay was terminated by rapid filtration through Packard UniFilter GF/B using a Packard harvester and washed four times with 1 ml ice-cold buffer. After drying the filters at 40°C for 1 h, 40 pL Microscint (Packard) was added to the filters and radioactivity of the filters was determined by a TopCount NXT (PerkinElmer, Waltham, MA; Alper and Nelson, Eur. J. Pharmacol. 1998, 343, 303-312; Rinken et al, Biochem. Pharmacol. 1999, 57, 155-162). Data thus gathered were used to détermine PAM EC50 values for each compound as primary in vitro activity end point.

In Table 1 compounds of this invention measured in the [³⁵S]GTPyS binding assay are 5 listed.

Table 1

Number of example	In vitro PAM potency
1	++
2	++
3	+
4	++
5	-F+
6	++
7	+
10	++
11	++
12	++
13	+
14
15	++
16	+
17	++
18	+
19	+++
20	++++
21	+++
22	++++
23	++
24	+++
25	+++

26	+++
27	++
28	+++
29	+++
30	++
31	+++
32	+++
34	++
35	++
36	++++
37	++++
40	++
42	++++

+ P AM EC50 < 1 nM ++ 1 nM < PAM EC50 < 10 nM +++ 10 < PAM EC50 < 100 nM ++++ 100 < PAM EC50 < 1000 nM

Foot shock-induced ultrasonic vocalization (USV) in adult rats

Under stressful conditions, adult rats émit 22 kHz ultrasounds that can be reduced by various pharmacological treatments (De Vry et al, Eur. J. Pharmacol. 1993, 249, 331-339; Sanchez, Eur. J. Pharmacol. 2003, 463, 133-143). Previous unpublished experiments indicated that GABAb receptor ligands can also inhibit vocalizatons that are induced by electric footshocks as stressor. Therefore, a foot shock-induced vocalization paradigm in adult rats was used to assess efficacy of centrally acting GABAb receptor ligands. Behavioral measurements were carried out on male Wistar rats (200-250 g, Toxicoop, Hungary). Rats were housed in groups of four in plastic cages with a wire grid top in a température and light-controlled laboratory animal care unit (22 ± 2 oC, 12-h light/dark cycle, lights on at 6:00 AM) with ad libitum access to commercial pellet rat food and tap water. Investigations were approved by the Local Ethical Committee of Gedeon Richter Pic. and were carried out in strict compliance with the European Directive 2010/63/EU regarding the care and use of laboratory animais for experimental procedures and ail efforts were made to minimize the number of animais as well as their suffering. In order to evoke émission of ultrasounds, animais were footshocked after a habituation period of 30 s (6 shocks, 1 s, 0.8 mA each, inter-shock interval 10 s) in a Sound attenuated shocking chamber (Experimetria, 40x40x80 cm). Investigational compounds were 5 administered at the dose of 1 mg/kg in a solid dispersion formulation in distilled water 1 h before shocking per os. Vocalizations were measured right after the last footshock for 10 min with a Metris Sonotrack System and the total time of vocalizations was registered. Vocalization of parallel vehicle treated animais was considered as control value and inhibition percent was calculated for each compound. At approximately 75 min after treatment and behavioral 10 measurements, blood and brain samples were harvested in order to détermine exposures associated with in vivo activity.

In Table 2 compounds of this invention measured in the USV assay are listed. In Table 3 plasma and brain levels of compounds of this invention are listed.

Table 2

Number of example	USV inhibition at 1 mg/kg (%)
2	85
3	100
11	71
12	59
13	97
15	89
16	100
17	79
18	75
33	63
35	57

Table 3

Number of example	plasma exposure at 1 mg/kg (ng/mL)	brain exposure at 1 mg/kg (ng/g)
2	188	74
3	58	18
11	146	68
12	121	62
13	124	31
15	170	53
16	131	36
17	135	74
18	175	30
33	172	34
35	207	35

Prénatal valproate model of autism spectrum disorder (ASD)

The prénatal valproate model has excellent construct and face validity, therefore it is a widely accepted disease model of ASD (Christensen et al, JAMA 2013, 309,1696-1703; Roullet et al, Neurotox. Teratol. 2013, 36, 45-56). In this method, time-mated female Wistar rats (Harlan UK) were administered a single dose of valproic acid (VPA, 600 mg/kg, i.p.) on gestational day 12.5. Male offspring were housed according to standard laboratory conditions until time of testing at postnatal day 59. Animais were housed in groups of 4 in conventional cages and maintained at 22-24°C on a standard 12 hour light/dark cycle (07.30-19.30), with food and water available ad libitum. After investigational drug treatment, offspring were examined behaviorally in the social preference assay at postnatal day 59. The social preference test is a highly accepted assay to assess autistic behavior in rodents (Nadler et al, Genes Brain

Behav. 2007, 3, 303-314; Bambini-Junior et al, Brain Res. 2011, 1408, 8-16). Briefly, in this assay a test animal is allowed to investigate a conspecific separated by a dividing perforated wall or a similar area however, without a target conspecific. An autistic animal (such as a prenatally valproate-exposed rat) spends little time with social investigation during a test session.

The inventors unexpectedly found that selected compounds of the invention in the oral dose range of 0.01 - 3 mg/kg were of great behavioral benefit in the présent preclinical disease model that récapitulâtes the core symptoms of ASD. The inventors therefore showed that these compounds may be of therapeutic potential for the treatment of core symptoms of ASD in humans.

EXAMPLES

The invention is further defined in the following Examples. It should be understood that the Examples are given by way of illustration only. From the above discussion and the Examples, one skilled in the art can ascertain the essential characteristics of the invention, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt the invention to various uses and conditions. As a resuit, the invention is not limited by the illustrative examples set forth herein below, but rather defined by the claims appended hereto.

In general, the compounds of formula (I) can be prepared according to the general knowledge of one skilled in the art and/or using methods set forth in the Example and/or Intermediate sections that follow. Solvents, températures, pressures, and other reaction conditions can readily be selected by one of ordinary skill in the art. Starting materials are commercially available and/or readily prepared by one skilled in the art.

Our patent application filed concurrently herewith titled “Process for the séparation of optical isomers of racemic 3-alkylpiperidine-carboxylic acid ethyl esters” discloses the préparation of certain starting materials.

The présent invention will be now illustrated by the following not limiting examples.

Intermediate 1

Ethyl 3-methylpiperidine-3-carboxvlate

a) l-Terf-butyl 3-ethyl 3-methylpiperidine-L3-dicarboxylate

Under nitrogen to a solution of 22.96 g (89 mmol) of 1 -terZ-butyl 3-ethyl piperidine-1,3dicarboxylate in 300 mL of dry tetrahydrofùran 100 mL of 1 M lithium bis(trimethylsilyl)amide in tetrahydrofuran solution (100 mmol) was added dropwise at (-78) °C - (-65) °C. After addition the mixture was stirred at -78°C for 20 min, 6.6 mL (106 mmol) of iodomethane was added dropwise. The so obtained mixture was allowed to warm to room température and stirred at this température for 18 h. The reaction was quenched by addition of200 mL of saturated ammonium chloride solution (pH ~8) and 300 mL of water. The reaction mixture was extracted with ethyl acetate, the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:4) to yield 24.2 g (95%) of the title compound as oil.

b) Ethyl 3-methylpiperidine-3-carboxylate

To a solution of 50 ml of 2.5 M hydrochloric acid in ethyl acetate 24.2 g (84.8 mmol) of 1fô/7-butyl 3-ethyl 3-methylpiperidine-l,3-dicarboxylate was added. The reaction mixture was stirred for 3 h at 20 °C, then 100 mL of diethyl ether was added. The precipitated crystals were filtered off, washed with diethyl ether to yield 16.28 g (97 %) of the title compound.

Intermediate 2

Ethyl 3-ethyIpiperidine-3-carboxyIate

a) 1-tm-Butyl 3-ethyl 3-ethylpiperidine-l J-dicarboxylate

The title compound is prepared from 1-tert-butyl 3-ethyl piperidine-1,3-dicarboxylate and iodo ethane according to the method described in Intermediatela.

b) Ethyl 3-ethylpiperidine-3-carboxylate hydrochloride

The title compound is prepared from 1-tert-butyl 3-ethyl 3-ethylpiperidine-1,3dicarboxylate according to the method described in Intermediate 1 b.

Intermediate 3 ch₃h₃c—/ O

Ethyl 3-(propan-2-yl)piperidine-3-carboxylate hydrochloride

a) 1-tert-Butyl 3-ethyl 3-(propan-2-yl)piperidine-1,3-dicarboxylate

The title compound is prepared from 1-tert-butyl 3-ethyl piperidine-1,3-dicarboxylate and 2-iodo propane according to the method described in Intermediatela.

b) Ethyl 3-(propan-2-yl)piperidine-3-carboxylate

The title compound is prepared from 1-tert-butyl 3-ethyl 3-(propan-2-yl)piperidine- 1,3dicarboxylate according to the method described in Intermediatelb.

Intermediate 4

Ethyl 3-propylpiperidine-3-carboxvlate hydrochloride

a) l-7ert-butyl 3-ethyl 3-propylpiperidine-1.3-dicarboxylate

Under nitrogen to a solution of 10 g (38.86 mmol) of l-ter/-butyl 3-ethyl piperidine-1,3dicarboxylate in 120 mL of dry tetrahydrofuran 42 mL of 1 M lithium bis(trimethylsilyl)amide in tetrahydrofuran solution (42 mmol) was added dropwise at (-78) °C - (-65) °C. After addition the mixture was stirred at -78°C for 20 min, 3.9 mL (39.7 mmol) of 1-iodopropane was added dropwise. The so obtained mixture was allowed to warm to room température and stirred at this température for 18 h. The reaction was quenched by addition of200 mL of saturated ammonium chloride solution (pH ~8) and 300 mL of water. The reaction mixture was extracted with ethyl acetate, the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:4) to obtain the title compound as oil. The crude product is used in the next step.

b) Ethyl 3-propylpiperidine-3-carboxylate hydrochloride

To the above obtained 1-terAbutyl 3-ethyl 3-propylpiperidine-l,3-dicarboxylate 20 ml of 2.5 M hydrochloric acid in ethyl acetate was added. The reaction mixture was stirred for 3 h at 20 °C, then concentrated in vacuo to yield 11.85 g of the title compound as oil.

Intermediate 5

Ethyl 3-(fluoromethyl)piperidine-3-carboxvlate hydrochloride

a) 1 -terAButyl 3-ethyl 3-(hydroxymethyl)piperidine-1,3-dicarboxylate

The title compound is prepared from 1-terAbutyl 3-ethyl piperidine-l,3-dicarboxylate and paraformaldéhyde according to the method described in Intermediatela.

b) 1 -tert-Butyl 3 -ethyl 3 - {[( L1,2-trifluoroethanesulfony Doxy]methyl}piperidine- L 3 dicarboxylate

Under nitrogen, to a stirred solution of 0.296 g (1.03 mmol) of ethyl 3-(hydroxymethyl) piperidine-3-carboxylate and 0.120 ml (1.48 mmol) of pyridine in 5 ml of dichloromethane

0.230 ml (1.48 mmol) of trifluoromethanesulfonic anhydride was added dropwise at (-78) °C (-65) °C. After addition the mixture was stirred at -78°C for 5 min and allowed to warm to room température and stirred at this température for 18 h. The reaction was quenched by addition of IM hydrochloric acid solution. The reaction mixture was extracted with dichloromethane, the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to obtain the title compound as oil. The crude product is used in the next step.

c) l-fe/7-Butyl 3-ethyl 3-(fluoromethyl)piperidine-L3-dicarboxylate

The above obtained 1-tert-butyl 3-ethyl 3-{[(l,l,2-trifluoroethanesulfonyl)oxy] methyl}piperidine-l,3-dicarboxylate was solved in 4 ml of tetrahydrofùran and 1.25 ml (1.25 mmol) of IM tetrabutylammonium fluoride in tetrahydrofuran was added. The reaction mixture was stirred for 1 h at room température, diluted with water and extracted with ethylacetate. The combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:2) to yield 0.121 g (40%) of the title compound.

d) Ethyl 3-(fluoromethyl)piperidine-3-carboxylate hydrochloride

The title compound is prepared from 1-fôrAButyl 3-ethyl 3-(fluoromethyl)piperidine-l,3dicarboxylate according to the method described in Intermediate 1b.

Intermediate 6 h₃c \

Ethyl 3-(methoxymethyl)piperidine-3-carboxylate hydrochloride

a) 1-ferAButyI 3-ethyl 3-(methoxymethyl)piperidine-L3-dicarboxylate

The title compound is prepared from 1-ZerAbutyl 3-ethyl piperidine-l,3-dicarboxylate and chloromethyl methyl ether according to the method described in Intermediate la.

b) Ethyl 3-(methoxymethyl)piperidine-3-carboxylate hydrochloride

The title compound is prepared from l-/er/-butyl 3-ethyl 3-(methoxymethyl)piperidine1,3-dicarboxylate according to the method described in Intermediate 1b.

Intermediate 7

3-itrans-4-(Trifliioromethvl)cvclohexvl]-lH-pyrazol-5-amine

a) Methyl trans-4-(trifluoromethyl)cyclohexane-1 -carboxylate

To a solution of 10 g (51 mmol) of trans 4-(trifluoromethyl)cyclohexane-l-carboxylic acid in 150 ml of methanol 10 ml (137 mmol) of thionyl chloride was added dropwise at -10 °C. After addition the mixture was allowed to warm to room température and stirred at this température for 16 h, then concentrated in vacuo. The residue was partitioned between ethyl acetate and water. The combined organic layer was washed with sodium hydrogéné carbonate solution and water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. Dry cyclohexane was evaporated from the residue several times to yield 8.96 g of the title compound as colourless oil.

b) 3-Oxo-3-rtrans-4-(trifluoromethyl)cyclohexyl]propanenitrile

Under nitrogen to a mixture of 9.1 ml (174 mmol) of acetonitrile in 260 ml of dry tetrahydrofuran 51 ml of 2.5 M n-butyllithium in n-hexane solution (127 mmol) was added dropwise at (-78) °C - (-65) °C. After addition the mixture was stirred at -78°C for 1 h, 8.96 g (42.6 mmol) of methyl trans-4-(trifluoromethyl)cyclohexane-l-carboxylate was added dropwise. The so obtained mixture was allowed to warm to room température and stirred at this température for 1 h. The reaction was quenched by addition of 150 mL of saturated ammonium chloride solution. The tetrahydrofuran was evaporated and the mixture was extracted with ethyl acetate. The combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product is used in the next step.

c) 3 - [trans-4-(Trifluoromethyl)cyclohexyll -1 H-pyrazol-5 -amine

The above obtained 3-oxo-3-[trans-4-(trifluoromethyl)cyclohexyl]propanenitrile was solved in 187 ml of éthanol and 4.4 ml (167 mmol) of hydrazine monohydrate was added. Under inert gas atmosphère, the reaction mixture was refluxed for 16 h. The solvent was removed in vacuo and dry toluene was evaporated from the residue several times to yield 11.15 g of the title compound as yellow oil. LC-MS (ESI) m/z 234.2 [MH⁺]

Intermediate 8

3-(4,4-Difliiorocyclohexvl)-l H-pyrazol-5-amine

a) 3-(4,4-Difluorocyclohexyl)-3-oxopropanenitrile

Under nitrogen to a mixture of 5 mL (95.7 mmol) of acetonitrile in 150 ml of dry tetrahydrofùran 29 ml of 2.5 M n-butyllithium in n-hexane solution (72.5 mmol) was added dropwise at (-78) °C - (-65) °C. After addition the mixture was stirred at -78°C for 1 h, 4.2 ml (24 mmol) of ethyl 4,4-difluorocyclohexane-l-carboxylate was added dropwise. The so obtained mixture was allowed to warm to room température and stirred at this température for 2 h. The reaction was quenched by addition of 150 mL of saturated ammonium chloride solution and and the mixture was extracted with ethyl acetate. The combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product is used in the next step.

b) 3-(4,4-Difluorocyclohexyl)-1 H-pyrazol-5-amine

The above obtained 3-oxo-3-[trans-4-(trifluoromethyl)cyclohexyl]propanenitrile was solved in 100 ml of éthanol and 4 ml (128.4 mmol) of hydrazine monohydrate was added. Under inert gas atmosphère, the reaction mixture was refluxed for 16 h. The solvent was removed in vacuo .The residue was partitioned between ethyl acetate and water. The combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to yield 6.43 g of the title compound as yellow oil. LC-MS (ESI) m/z 202.2 [MH⁺]

Intermediate 9

F

3-(4,4-Difluorocvclohexvi)-4-fluoro-lH-pyrazoI-5-amine

The title compound was prepared from 4,4-difluorocyclohexane-l-carboxylic acid and fluoroacetonitrile according to the method described in Intermediate 7.

Intermediate 10

F

4-fluoro-3-|trans-4-(trifluoromethvl)cvcIohexvI]-lH-pvrazol-5-amine

a) trans-4-(Trifluoromethyl)cyclohexane-1 -carbonyl chloride

A mixture of 5 g (25.5 mmol) of trans 4-(trifluoromethyl)cyclohexane-l-carboxylic acid, 100 ml of dichloromethane, 5 ml (68.5 mmol) of thionyl chloride and 0.1 ml of dimethyformamide was refluxed for 6 h. The reaction mixture was concentrated in vacuo and 15 dry tetrahydrofùran was evaporated from the residue several times. The crude product is used in the next step.

b) 2-Fluoro-3-oxo-3-[trans-4-(trifluoromethyl)cyclohexyl]propanenitrile

Under inert gas atmosphère, to a solution of the above obtained trans-4-(trifluoromethyl) cyclohexane-1-carbonyl chloride and 1.5 ml (26.96 mmol) of fluoroacetonitrile in 50 mL of 20 abs. tetrahydrofuran 50 mL (50 mmol) of IM lithium bis(trimethylsilyl)amide was added dropwise at - 78 °C. After addition the mixture was stirred at -78°C for 1 h, then the mixture was allowed to warm to room température and poured into 200 mL of water. The pH of the mixture was adjusted to 2 by the addition of IM hydrochloric acid. The mixture was extracted with ethyl acetate, the combined organic layer was washed with water, dried over anhydrous 25 sodium sulfate, fdtered and concentrated in vacuo. The crude product is used in the next step.

c) 4-Fluoro-3-[trans-4-(trifluoromethyl)cyclohexyl]-lH-pyrazol-5-amine

The above obtained 2-fluoro-3-oxo-3-[trans-4-(trifluoromethyl)cyclohexyl]propanenitrile was dissolved in 65 ml of éthanol and 4.4 ml (77 mmol) of hydrazine monohydrate was added. Under inert gas atmosphère, the reaction mixture was refluxed for 16 h. The solvent was removed in vacuo to obtain the title compound as oil. LC-MS (ESI) m/z 252.2 [MH⁺]

Intermediate 11

5-amino-34trans-4-(trifluoromethvl)cvclohexyl]-lH-Dvrazole-4-carbonitrile

a) 2-[trans-4-(trifluoromethyl)cyclohexanecarbonyllpropanedinitrile

To a mixture of 2. 7g (12.58 mmol) trans-4-(trifluoromethyl) cyclohexane-1-carbonyl chloride (Intermediate 10a) and 1.26 g (19.0 mmol) of malononitrile in 15 mL of abs. tetrahydrofùran 1.77 mL (50 mmol) of triethylamin was added dropwise at 0 °C. After addition the mixture was stirred at 0 °C for 1 h, then the mixture was allowed to warm to room température and poured into 200 mL of water. The mixture was extracted with ethyl acetate, the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product is used in the next step.

b) 2-{methoxyrtrans-4-(trifluoromethyl)cyclohexyl]methylidene}propanedinitrile

To the above obtained 2-[trans-4-(trifluoromethyl)cyclohexanecarbonyl]propanedinitrile ml of trimethyl orthoformate was added. The reaction mixture was refluxed for 16 h. The reaction mixture was concentrated in vacuo and the residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:1) to yield 1.495 g (46.0 %) of the title compound as oil. LC-MS (ESI) m/z 259.1 [MH⁺]

c) 5-amino-3-rtrans-4-(trifluoromethyl)cyclohexyl1-lH-pyrazole-4-carbonitril

The above obtained 2-{methoxy[trans-4-(trifluoromethyl)cyclohexyl]methylidene) propanedinitrile was dissolved in 17 ml of éthanol and 1.4 ml (24.5 mmol) of hydrazine monohydrate was added. The reaction mixture was stirred for 0.5 h at room température, diluted with water and extracted with ethylacetate. The combined organic layer was washed with water, dried over anhydrous sodium sulfate, fdtered and concentrated in vacuo to yield 1.04 g (69.5%) of the title compound. LC-MS (ESI) m/z 259.2 [MH⁺]

Intermediate 12

Cl ch₃

7-Chloro-5-methyl-6-(propan-2-vl)-2-[trans-4-(trifluoromethyl)cvclohexyl] pyrazolo [1,5-a] pyrimidine

a) 5-Methyl-6-(propan-2-yl)-2-|trans-4-(trifluoromethyl)cyclohexyllpyrazolo[1.5a]pyrimidin-7-ol

A mixture of 11.156 g (47.8 mmol) of 3-[trans-4-(trifluoromethyI)cyclohexyl]-lH-pyrazol-5amine (Intermediate 7), 8 ml (44.6 mmol) of ethyl 2-acetyl-3-methylbutanoate and 0.32 g (1.6 mmol) of p-toluenesulfonic acid monohydrate in 340 mL of toluene was refluxed for 20 h, then cooled to room température. The reaction mixture was concentrated in vacuo and the residue was chromatographed on silica gel eluting with dichloromethane and methanol (20:1) to yield 12.4 g (76%) of the title compound. LC-MS (ESI) m/z 342.2 [MH⁺]

b) 7-Chloro-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo! L5-alpyrimidine

A mixture of 12.4 g (36.35 mmol) of 5-methyl-6-(propan-2-yl)-2-[trans-4(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidin-7-ol, 16.7 ml(179 mmol) of phosphores oxychloride, 12.7 ml (72.9 mmol) of Ν,Ν-diisopropylethylamine and 733 ml of toluene was refluxed for 20 h. The reaction mixture was cooled to 20 °C, poured into a mixture of sodium hydrogen carbonate solution and ice, then stirred for 2 h. The reaction mixture was filtered, the filtrate was extracted with ethyl acetate, the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to yield 12.05 g (92%) of the title compound. LC-MS (ESI) m/z 360.2 [MH⁺]

Compounds of Table 4 were prepared from the appropriate acetoacetic ester and 1Hpyrazo 1-5-amine according to the method described in Intermediate 12.

Table 4

Intermediate	Structure	Intermediate (starting material)	LC-MS (ESI) m/z [MH⁺]
13	a ch₃ ^{F F} '---F	10	360.2
14	a F /---\ hL /L· \ / \ „Z\| ^{F F} '----'	7	348.1
15	Cl \ / \ „ // N CH₃ ^{F F} '----^/ F	10	366.2
16	a ^{F F} '----'	7	346.1
17	5 δ	7	360.2
18	Cl ch₃ F y-----. M \/ \__// f ^CH3	8	328.2
19	Q δ-/ δ	9	346.2
20	Cl V/ \„y/ 7 7 i A \ / J	7	358.2

21	Cl \.....λ γ Λ	7	372.2
22	Cl \......y ? _{F F} \--/	7	360.2
23	Cl v_/ \.....γ η F F '---/	7	360.1
24	h; \___/ w	7	372.2
25	Cl CH₃ \ / \......	11	385.2
26	-n m K À O / 0 JE	7	376.2

Route c)

Example 1

(3S)-1- [ 5-Methyl-6-(propan-2-yl)-2- [trans-4-(trifluoromethyl)cy clohexyl] pyrazolo [1,5a]pyrimidm-7-vl]piperidine-3-carboxvlic acid

A mixture of 0.8 g (2.22 mmol) of 7-chloro-5-methyl-6-(propan-2-yl)-2-[trans-4(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidine (Intermediate 12), 0.5 g (3.87 mmol) of

S-nipecotic acid and 0.7 ml (4 mmol) of Ν,Ν-diisopropylethylamine in 20 mL of W-methylpyrrolidone was heated at 130 °C for 20 h, then cooled and diluted with water. The reaction mixture was extracted with ethylacetate, the combined organic layer was washed with water, dried over anhydrous sodium sulphate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:2) to yield 0.422 g (42.0 %) ofthe title compound. LC-MS (ESI) m/z 453.2 [MH⁺]

Route d)

Example 2

(3S)-l-[5-Methvl-6-(propan-2-vr)-2-|trans-4-(trifluoromethvl)cyclohexvl]Pvrazolo[l,5-aÎpvrimidin-7-vll-3-(propan-2-vl)piperidine-3-carboxvlic acid

A mixture of 0.66 g (2.79 mmol) of ethyl (3S)-3-(propan-2-yl)piperidine-3-carboxylate hydrochloride, 0.66 g (5.88 mmol) of potassium tert-butoxide in 15 mL of dimethyl sulfoxide was heated at 100 °C for 16 h. Then 1.0 g (2.77 mmol) 7-chloro-5-methyl-6-(propan-2-yl)-2[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidine (Intermediate 12) was added to the mixture and heated at 120 °C for 16 h. The reaction mixture was cooled and acidified with acetic acid. The precipitated crystals were filtered off, washed with water. The crude product was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:2) to yield 0.506 g (36.8 %) ofthe title compound. LC-MS (ESI) m/z 495.3 [MH⁺]

Route e)

(3R)-3-methvll-[5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethvl)cyclohexyl]pyrazolo H,5-a]pvrimidm-7-yllpiperidine-3-carboxYlic acid

a) Ethyl(3R)-3-methyl-l-r5-methyl-6-(propan-2-yl)-2-rtrans-4-(trifluoromethyl) cyclohexyllpyrazolori.5-a1pyrimidin-7-yl1piperidine-3-carboxylate

A mixture of 1.0 g (3.06 mmol) of 7-chloro-5-methyl-6-(propan-2-yl)-2-[trans-4(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidine (Intermediate 12), 0.76 g (4.43 mmol) of ethyl (3R)-3-methylpiperidine-3-carboxylate and 0.8 mL (4.592 mmol) of Ν,Νdiisopropylethylamine in 20 mL of A-methyl-pyrrolidone was heated at 130 °C for 20 h, then cooled and diluted with water. The reaction mixture was extracted with ethylacetate, the combined organic layer was washed with water, dried over anhydrous sodium sulphate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with toluene and aceton(10:l)to yield 1.44 g (95.3 %) ofthe title compound. LC-MS (ESI) m/z 495.3 [MH⁺]

b) (3R)-3-methyl-l-[5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl1 pyrazolo ri.5-a1pyrimidin-7-yl]piperidine-3-carboxylic acid

A mixture of 1.443 g (2.91mmol) of ethyl (3R)-3-methyl-l-[5-methyl-6-(propan-2-yl)-2[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidin-7-yl]piperidine-3-carboxylate and 5 mL of 20% sodium hydroxide solution in 40 mL of éthanol was refluxed for 5 h, then cooled and acidified with acetic acid. The reaction mixture was extracted with dichloromethane, the combined organic layer was washed with water, dried over anhydrous sodium sulphate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethylacetate and cyclohexane (1:2) to yield 0.934 g (68.6 %) of the title compound. LC-MS (ESI) m/z 467.3 [MH⁺]

Example 4 and Example 5

AT CH.

A and B enantiomer (3R)-l-r5-methvI-6-(propan-2-vh-2-[trans-4-(trifluoromethvl)cvclohexvl]pyrazolo[l,5a]pvrimidin-7-vl]-3-propvlpiperidine-3-carboxvlic acid and (3S)-l-I5-methyl-6-(propan-2-vl)-2-rtrans-4-(trifluoromethyl)cvclohexvllpvrazolofl,5alpvrimidin-7-yl]-3-propylpiperidine-3-carboxylic acid

The racemic form of the title compounds were prepared from 7-chloro-5-methyl-6(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[ 1,5-a]pyrimidine (Intermediate 12), and racem ethyl 3-propylpiperidine-3-carboxylate hydrochloride (Intermediate 4b) according to the methods described in Example 2a and 2b. LC-MS (ESI) m/z 495.3 [MH⁺], The A and B enantiomers were separated using chiral préparative HPLC (Kromasil Cellucoat RP 5pm 150x4.6mm; F=lml/min; eluents:A: H2O+30mM AmAc B:80ACN+30mM AmAc; isocratic70%B t=25°C) obtaining enantiomer A (T_r 10.464, Example 4), and enantiomer B (T_r 11.584, Example 5). Their absolute configuration is not determined.

Example 6 and Example 7

A and B enantiomer (3R)-3-(FIuoromethvD-l-[5-methyl-6-(propan-2-vl)-2-|trans-4(trifliioromethvl)cvclohexyllpyrazolofl,5-alpyrimidin-7-vl]piperidine-3-carboxylic acid and (3S)-3-(Fluoromethyl)-l-[5-methyl-6-(propan-2-vl)-2-[trans-4(trifluoromethvl)cvclohexyllpyrazoloH,5-al pyrimidin-7-yl]piperidine-3-carboxylic acid

The racemic form of the title compounds were prepared from 7-chloro-5-methyl-6(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidine (Intermediate 12), and racem Ethyl 3-(fluoromethyl)piperidine-3-carboxylate hydrochloride (Intermediate 5) according to the methods described in Example 2a and 2b. LC-MS (ESI) m/z 485.3 [MH+], The A and B enantiomers were separated using chiral préparative HPLC (Lux Amylose-1 5pm 250x21.1 mm ; F=21ml/min; eluents: n-Heptane : EtOH 80 : 20 + 0,1% TFA t= 40°C) obtaining enantiomer A(Tr 5.9, Example 6 ), and enantiomer B (Tr 6.7, Example 7). Their absolute configuration is not determined.

Example 8 and Example 9 h₃ç 9

N

A and B diastereomer (3R)-3-methvl-l-[(8S)-8-methyl-2-[trans-4-(trifluoromethvl)cyclohexvn-5H,6H,7H,8Hpyrazolo [3,2-b] q uinazolin-9-yl] piperidine-3-carboxylic acid and (3R)-3-methyl-l-[(8R)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexvll-5H,6H,7H,8Hpyrazolo[3,2-b]quinazolin-9-yl]piperidine-3-carboxylic acid

a) Ethyl (3R)-3-methyl-l-[(8S)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl15H, 6H, 7H, 8H-pyrazolo [3,2-b] quinazolin-9-yl]piperidine-3 -carboxylate and

Ethyl (3R)-3-methyl-l-r(8R)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyll5H,6H,7H.8H-pyrazolo[3,2-b]quinazolin-9-yl]piperidine-3-carboxylate

The racemic form of the title compounds were prepared from racem 9-chloro-8-methyl2-[trans-4-(trifluoromethyl)cyclohexyl]-5H,6H,7H,8H-pyrazolo[3,2-b]quinazoline (Intermediate 24), and ethyl (3 R)-3-methylpiperidine-3-carboxylate hydrochloride according to the methods described in Example 2a. The A and B diastereomer esters were separated using column chromatography on silica gel eluting with dichloromethane-diisopropyl ether 10-1, obtaining diastereomer A ester (TLC in the same system rf = 0.5) and diastereomer B ester (TLC in the same System rf = 0.45).

b) (3R)-3-Methyl-l-[(8S)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyll5H,6H,7H,8H-pyrazolor3.2-b1quinazolin-9-yl1piperidine-3-carboxylic acid and (3R)-3-Methyl-l-r(8R)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyll5H,6H.7H,8H-pyrazolo[3.2-b]quinazolin-9-yl1piperidine-3-carboxylic acid

The title compounds were prepared from above diastereomer A ester (Example 8, LCMS (ESI) m/z 479.2 [MH⁺]) and diastereomer B ester (Example 9, LC-MS (ESI) m/z 479.2 [MH⁺]) according to the methods described in Example 2b. Their absolute configuration is not determined.

Examples 10-42 were prepared using analogues methods to those Examples described above and are exemplified below in Table 5.

Table 5

Example	Structure	LC-MS (ESI) m/z [MH⁺]	Intermediate	Route
10	O¹ Te ch₃ F /---y N·^ /V. \ / \ ..,,/ι ^CH3 ^{F F} '----^/	453.2	12	c
11	o CH₃ ^F\ / \......y ^{F F}	467.3	12	e

12	H₃C. 0 c¹¹- N CH₃ F /---< ,/k. /k \ / \ .....CH₃ ^{F F} '—	481.4	12	e
13	H_SC. O ck” CH₃ F /---\ N·^ xk \ / \.......// N CH₃ ^{F F} '---^X'^^N^<ÎÎ>^CH₃	481.4	12	e
14	CH3 O a.....t rr ch₃ F /--v M /k A. \ / \ γτ ^γ ^ch3 F F '----'	495.3	12	d
15	d^xίψ CH₃ ^F /--\ N-^ /k /k \ / \ // V ^γ ch₃ ^{F F} '----' F	485.3	13	e
16	ΆηV // \__/„.F 2 /“2 >=^o“ / “ s	485.3	13	e
17	H₃C-^ 0 r - N ÇH₃ ^F /--\ N-^ /k /k \ / \ ...../ 1 q ^CH3 _{F F} V^y Y^kf^kcHa F	499.3	13	e
18	/ \ / \ o γγ\)....../ 2 /-2 )=° ^ω O ^w 0 □: i	499.3	13	e

19	X z Ο Ο __/ / £ 0=¾ Ο Ο Y	455.2	14	d
20	V__ÿ \___Ζ.,,,Λ 8 Ο )=0 “ 2 2	455.2	14	d
21	H₃c-^ 0 Y Ν F τ----k Ν-— \ / \ // Ν 0Η₃ _{F F} \--/	469.2	14	d
22	HaC^ 0 ΥΓ F y---. ΓΎ χΧ. \ / \......Y । ^CHs ^{F F} '----'	469.2	14	d
23	H,C θ F /--v NY xX. x'°\ Y / \ A’N CH₃ F F '---' F	473.2	15	e
24	F i--NY xAs. \ / \ ^{N 043} F F '----f F	473.2	15	e
25	h₃c^ 0 a·- N^ F /--> N- xX. /°\ \ / \ ...../YY ^CHS ^{F F} '--' /*τΥτ_Η3 F	487.2	15	d

26	H₃C-^ 0 Cj“ TT F i---\ xAs. ......^CH’ F	487.2	15	e
27	h₃c 9 TT \ / \......// n ch₃ F F \	453.2	16	d
28	h₃c-^_ o \|^VOH TT \ / \......,/7^1 CH₃ F F ^X----^{/ X}	467.3	16	d
29	_ H. d N ÇH₃ F .----< n x'Ls. \/ \ /Z T ^CHs	435.2	18	e
30	c> N ÇH₃ F y----V N \/ \ / η^{1 ch}3 F '----	435.2	18	e
31	h₃c. 0 cN CH₃ ^F /---N-^ /L· \/ \ ^{N CH}3 _F \---/	449.3	18	e
32	h₃c^ o CH₃ F ----m__ x \ i ΊΓ ^CH:	449.3	18	e

33	N F i--\ /U. /—. \ / \......./ 7 ^7 ^CH3 ÆX / \^k<X/CH₃ ^{F F} TT	467.3	17	e
34	& rr	465.2	20	e
35	ô¹” ^'rr F /—3 ^N—> \ / \......z' ? © Λ F F '---/	479.2	21	e
36	H₃C iî _dA„ F /—\ Ν-^.,χΛ^Χ\_λ \ / \ Λ N O F F \---⁷	467.2	22	e
37	A ΛΑ Q% O--' o z	467.2	23	e
38	o < η-“ OH ΊΓ î^H3 F /---\ N-^ ✓As. ✓As. \ / \ // n ch₃ F F \-/ V^n^CH₃ // N	492.3	25	e
39	O ✓<Γ1. ^- OH ch₃ F j--< ✓A^ ✓À. )^ΛΛ......^CHs _F f '-/ V^N^CH, III N	492.3	25	e

40	Ο çhJ] CH₃ ^F\/ \ F '--' /’^N'''^CH₃ F	453.2	18	e
41	ÇH₃o. 1 ° TT CH₃ F i---\ /An. \ / \ ₍ //’ N CH₃ ^F F '----'	497.2	12	e
42	h₃c 2 F /--\ Ν-_,/Λν/\ \_/ \......# 7 F F \--/	467.2	23	e
43	n₃c 2 F /---< xAn. /-⁰^ \ / \ ^ch3 ^F F '--' ^N<^CH₃	483.3	26	e

Préparation of pharmaceutical compositions

The following formulation examples illustrate représentative pharmaceutical compositions of this invention. The présent invention however is not limited to the following pharmaceutical compositions.

A) Solid oral dosage forms

I., Tablets

Active ingredient(s)	0.01-90%
10 Filler	1 - 99.9%
Binder	0 - 20%
Disintegrant	0 - 20%
Lubricant	0-10%
Other spécifie excipient(s)	0 - 50%
15
IL, Orodispersiblefilms
Active ingredient(s)	0.01-90%
Film forming agent	1 - 99.9%
Plasticizer	0 - 40%
20 Other spécifie excipient(s)	0 - 50%
B) Liquid oral dosage forms
III., Oral suspensions
25 Active ingredient(s)	0.01-50%
Liquid vehicle	10-99.9%
Wetting agent	0 - 50%
Thickener	0 - 50%
Buffering agent	q.s.
30 Osmotic agent	0 - 50%
Preservatives	q.s.
IV., Syrups
Active ingredient(s)	0.01-50%
35 Solvent	10-99.9%
Sugar component	1 - 20%
Flavouring agents	0-10%

C) Parentéral dosage forms

V., Intravenous injections

Active ingredient(s) Solvent

Co-solvent

Osmotic agent

Buffering agent

D) Other dosage forms

VL, Suppositories

Active ingredient(s) Suppository base Surface-active agents Lubricants

Preservatives

VIL, Eye drops

Active ingredient(s)

Water

Solvent

Osmotic agent

Viscosity enhancer Buffering agent Preservatives

Claims

1. A compound of formula (I) wherein:

R¹ and R² are independently selected from hydrogen, halogen atom, Ci-ealkyl, haloCi-ealkyl;

R³ is hydrogen, halogen atom, Ci-6alkyl, cyano group;

R⁴ is Ci-ealkyl;

R⁵ is Ci-ôalkyl optionally substituted by a halogen atom or halogen atoms, C3-5 cycloalkyl;

C3-5 cycloalkylCi-ealkyl, dialkylamino, Ci-ealkoxy, Ci-ealkoxyCi-ealkyl, Ci-ealkylthio group, tetrahydrofuranyl, tetrahydrofuranylCi-ealkyl, tetrahydropyranyl, tetrahydropyranylCi-ôalkyl;

or R4 and R5 together form an unsubstituted or substituted by one or more Ci-3alkyl, Ci-3alkoxy, haloCi-salkyl, Ci-salkylcarbonyl 3 to 7-membered saturated ring, wherein the members of the ring are selected from the group consisting of carbon, nitrogen, oxygen, and sulphur;

R⁶ is hydrogen, halogen atom or Ci-ealkyl, hydroxyl, Ci-ealkoxy, Ci-ealkoxyCi-ôalkyl, haloCiealkyl, amino group; or pharmaceutically acceptable salts, biologically active métabolites, prodrugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof.

2. A compound according to claim 1 wherein

R¹ and R² are independently selected from hydrogen, halogen atom, Ci-ealkyl, haloCi-galkyl;

R³ is hydrogen, halogen atom, Ci^alkyl, cyano group;

R⁴ is Ci-6alkyl;

R⁵ is Ci-ealkyl optionally substituted by a halogen atom or halogen atoms, C3-5 cycloalkyl,

C3-5 cycloalkylCi-ealkyl, dialkylamino, Ci-6alkoxy, Ci-salkoxyCi-ealkyl, Ci-6alkylthio group, tetrahydrofuranyl, tetrahydrofuranylCi-ôalkyl, tetrahydropyranyl, tetrahydropyranylCi-ôalkyl;

R⁶ is hydrogen, halogen atom or Ci-6alkyl, hydroxyl, Ci-salkoxy, Ci-6alkoxyCi-6alkyI, haloCiealkyl, amino group; or pharmaceutically acceptable salts, biologically active métabolites, prodrugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof.

3. A compound according to claim 1 wherein

R¹ and R² are independently selected from hydrogen, halogen atom, Ci-ealkyl, haloCi-6alkyl;

R³ is hydrogen, halogen atom, Ci-ealkyl, cyano group;

R₄ and Rs together form an unsubstituted or substituted by one or more Ci-salkyl, Ci-3alkoxy, haloCi-salkyl, Ci-salkylcarbonyl 3 to 7-membered saturated ring, wherein the members of the ring are selected from the group consisting of carbon, nitrogen, oxygen, and sulphur;

R⁶ is hydrogen, halogen atom or Ci-galkyl, hydroxyl, Ci-ealkoxy, Ci-galkoxyCi-galkyl, haloCiealkyl, amino group or pharmaceutically acceptable salts, biologically active métabolites, prodrugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof.

4. A compound according to claim 1 wherein R⁴ is methyl; and R⁵ is isopropyl or Ci.6alkoxyCi. ôalkyl.

5. A compound according to claim 1 selected from the group of (3S)-l-[5-Methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3S)-l-[5-Methyl-6-(propan-2-yl)-2-[ trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl]-3-(propan-2-yl)piperidine-3-carboxylic acid (3R)-3-Methyl-l-[5-methyl-6-(propan-2-yl)-2-[ trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3R)-l-[5-Methyl-6-(propan-2-yl)-2-[ trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl]-3-propylpiperidine-3-carboxylic acid (3 S)- l-[5-Methyl-6-(propan-2-yl)-2-[ trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[ 1,5a]pyrimidin-7-yl]-3-propylpiperidine-3-carboxylic acid (3R)-3-(Fluoromethyl)-l-[5-methyl-6-(propan-2-yl)-2-[ trans-4(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3 S)-3 -(Fluoromethyl)-1 - [5 -methyl-6-(propan-2-yl)-2- [ trans-4(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3R)-3-Methyl-l-[(8S)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]-5H,6H,7H,8Hpyrazolo[3,2-b]quinazolin-9-yl]piperidine-3-carboxylic acid (3R)-3-Methyl-l-[(8R)-8-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]-5H,6H,7H,8Hpyrazolo[3,2-b]quinazolin-9-yl]piperidine-3-carboxylic acid (3R)-l-[5-Methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3S)-3-Methyl-l-[5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3 S)-3-Ethyl-1 -[5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyI]pyrazolo [l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3R)-3-Ethyl-l-[5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3R)-l-[5-Methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl]-3-(propan-2-yl)piperidine-3-carboxylic acid (3S)-l-[3-Fluoro-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [ 1,5 -a]pyrimidin-7-yl] -3 -methylpiperidine-3 -carboxylic acid (3R)-l-[3-Fluoro-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [l,5-a]pyrimidin-7-yl]-3-methylpiperidine-3-carboxylic acid (3S)-3-EthyI-l-[3-fluoro-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyI] pyrazolo[l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3R)-3-Ethyl-l-[3-fluoro-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl] pyrazolo[l,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid (3 S)-1 - { 3 -Fluoro-6-methoxy-5-methy 1-2- [trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [1,5a]pyrimidin-7-yl}-3-methylpiperidine-3-carboxylic acid (3R)-l-{3-Fluoro-6-methoxy-5-methyl-2-[trans-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl}-3-methylpiperidine-3-carboxylic acid (3 S)-3 -Ethyl-1 - { 6-methoxy-5 -methyl-2- [trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [1,5a]pyrimidin-7-yl}piperidine-3-carboxylic acid (3R)-3-Ethyl-l-{6-methoxy-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl}piperidine-3-carboxylic acid (3S)-l-{3-Fluoro-6-methoxy-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl}-3-methylpiperidine-3-carboxylic acid (3R)-l-{3-Fluoro-6-methoxy-5-methyl-2-[trans-4-(trifluoiOmethyl)cyclohexyl]pyrazolo[l,5a]pyrimidin-7-yl}-3-methylpiperidine-3-carboxylic acid (3S)-3-Ethyl-l-{3-fluoro-6-methoxy-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl] pyrazolo[l,5-a]pyrimidin-7-yl}piperidme-3-carboxylic acid (3R)-3-Ethyl-l-{3-fluoro-6-methoxy-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl] pyrazolo[l,5-a]pyrimidin-7-yl}piperidine-3-carboxylic acid (3R)-l-{6-Ethyl-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[l,5-a]pyrimidin7-yl} -3 -methylpiperidine-3 -carboxylic acid (3R)-3-Ethyl-1 -{6-ethyl-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[ 1,5a]pyrimidin-7-yl}piperidine-3-carboxylic acid (3S)-l-[2-(4,4-Difluorocyclohexyl)-5-methyl-6-(propan-2-yl)pyrazolo[l,5-a]pyrimidin-7-yl]3-methylpiperidine-3-carboxylic acid (3R)-l-[2-(4,4-Difluorocyclohexyl)-5-methyl-6-(propan-2-yl)pyrazolo[l,5-a]pyrimidin-7-yl]3-methylpiperidine-3-carboxylic acid (3 S)-1 - [2-(4,4-Difluorocyclohexyl)-5 -methyl-6-(propan-2-yl)pyrazolo [ 1,5 -a]pyrimidin-7-yl] 3 -ethylpiperidine-3 -carboxylic acid (3R)-l-[2-(4,4-Difluorocyclohexyl)-5-methyl-6-(propan-2-yl)pyrazolo[l,5-a]pyrimidin-7-yl]3-ethylpiperidine-3-carboxylic acid (3R)-l-[2-(4,4-Difluorocyclohexyl)-5,6-diethylpyrazolo[l,5-a]pyrimidin-7-yI]-3methylpiperidine-3 -carboxylic acid (3R)-3-Methyl-l-{2-[trans-4-(trifluoromethyl)cyclohexyl]-5H,6H,7H,8H-pyrazolo[3,2b]quinazolin-9-yl}piperidine-3-carboxylic acid (3R)-3-Methyl-l-{5-[trans-4-(trifluoromethyl)cyclohexyl]-2,6,7-triazatricyclo [7.5.0.0³,⁷]tetradeca-l,3,5,8-tetraen-8-yl}piperidine-3-carboxylic acid (3R)-3-Methyl-l-{5-[trans)-4-(trifluoromethyl)cyclohexyl]-ll-oxa-2,6,7-triazatricyclo [7.4.0.0³,⁷]trideca-l,3,5,8-tetraen-8-yl}piperidine-3-carboxylic acid (3 S)-3-Methyl-1 -{ 5-[trans-4-(trifluoromethyl)cyclohexyl]-12-oxa-2,6,7-triazatricyclo [7.4.0.0³,⁷]trideca-l,3,5,8-tetraen-8-yl}piperidine-3-carboxylic acid (3 S)-1 -[3-Cyano-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [ 1,5 -a]pyrimidin-7-yl]-3 -methylpiperidine-3 -carboxylic acid (3R)-l-[3-Cyano-5-methyl-6-(propan-2-yl)-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo [l,5-a]pyrimidin-7-yl]-3-methylpiperidine-3-carboxylic acid (3R)-1-[2-(4,4-Difluorocyclohexyl)-3-fluoro-5-methyl-6-(propan-2-yl)pyrazolo[ 1,5a]pyrimidin-7-yl]-3-methylpiperidine-3-carboxylic acid (3R)-1 -[6-(2-methoxyethyl)-5-methyl-2-[trans-4-(trifluoromethyl)cyclohexyl]pyrazolo[ 1,5a]pyrimidin-7-yl]-3-methylpiperidine-3-carboxylic acid

6. Process for preparing the compounds of formula (I) according to claim 1 characterized by step 1) reacting an carboxylic acid ester dérivative of formula (II) or carboxylic acid chloride dérivative of formula (III) ^R\/—\ /° ^R\/—\° ₂/\ / \ ^Or ₂A\ /-^R \---/ o—Alk R \/ Cl (H)(III)

- wherein the meaning of R¹ and R² is described above for compound of formula (I) with an acetonitrile dérivative of formula (IV)

- wherein the meaning of R³ is described above for compound of formula (I), then step 2) the so obtained acylacetonitrile dérivative of formula (V) is reacted

(V)

2a) with hydrazine hydrate to provide a compound of formula (VI)

5 - wherein the meaning of R¹, R² is as described above and R³ is hydrogen, halogen atom,

Ci-6alkyl group or

2b) with trimethyl orthoformate to provide the malononitrile dérivative of formula (xiv)

- wherein the meaning of RI, R2 is as described above and R3 is cyano group which is reacted with hydrazine hydrate to provide a compound of formula (VI)

15 then step 3) the compound of formula (VI) wherein the meaning of RI, R2, R3 is as described above for the formula (I) - obtained according to the steps described in 2a) or 2b) is reacted with acylacetic ester dérivative of formula (VII)

- wherein the meaning of R4 and R5 is as described above for the formula (I), then step 4) the so obtained compound of formula (VHI)

5 - wherein the meaning of R¹, R², R³, R⁴,and R⁵ is as described above for the formula (I) -is chlorinated to fürnish a chloro dérivative of formula (IX)

5c) a nipecotic acid dérivative of formula (X)

H (X)

5d) its alkali sait of formula (XI)

H (XI) wherein the meaning of R⁶ is as described above for the formula (I) - and the obtained compound of formula (I) and optical antipodes or racemates and/or salts thereof optionally can be transformed into an other compound of formula (I) and optical

5 antipodes or racemates and/or salts thereof by introducing new substituents and/or modifying or removing the existing ones, or

5e) a nipecotic acid ester dérivative of formula (XII)

H (XII)

10 - wherein the meaning of R⁶ is as described above for the formula (I) - to provide the ester dérivative of formula (XIII)

- wherein the meaning of R¹, R², R³, R⁴, R⁵ and R⁶ is as described above for the formula (I) finally the latter is saponified with a strong base or acid - and the obtained dérivative

15 of formula (I) and optical antipodes or racemates and/or salts thereof optionally can be transformed into an other compound of formula (I) and optical antipodes or racemates and/or salts thereof by introducing new substituents and/or modifying or removing the existing ones.

7. A pharmaceutical composition comprising a therapeutically effective amount of a compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 as active ingrédient and pharmaceutically acceptable carrier.

8. A combination comprising a therapeutically effective amount of a compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 and one or more therapeutically active co-agents.

9. Process for manufacturing pharmaceutical composition having GABAb receptor positive allosteric modulator effect characterized by mixing a therapeutically effective amount of a compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 and optical antipodes or racemates and/or salts thereof as active ingrédients andand pharmaceutically acceptable excipients.

10. A compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 for use as GABAb receptor positive allosteric modulator.

11. A compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 for use in the treatment or prévention of disorders associated with GABAb receptor positive allosteric modulator activity.

12. A compound of formula (I) or pharmaceutically acceptable salts, biologically active métabolites, pro-drugs, racemates, enantiomers, diastereomers, solvatés and hydrates thereof according to claim 1 for use according to claim 11 wherein the disorder is selected from the group of psychiatrie disorders (such as anxiety, panic disorder, posttraumatic disorder, dépréssion, schizophrenia), neurodevelopmental disorders (such as autism spectrum disorder, obsessive-compulsive disorder, Fragile X syndrome), cognitive disorders, epilepsy, spasticity, sceletal muscle rigidity, spinal cord injury, multiple sclerosis, amyotrophie latéral sclerosis, cérébral palsy, essential tremor, pain (neuropathie, viscéral, osteoarthritic), substance abuse (cocaïne, nicotine, alcohol), obesity, binge eating, asthma, cough, urinary incontinence, gastroesophageal reflux disease, transient lower esophageal sphincter relaxation, irritable bowel syndrome.

13. Method of treatment and/or prévention of a disorder which requires positive allosteric modulation of the GABAb receptor characterized by administering an effective amount of a compound of formula (I) as claimed in claim 1 and optical antipodes or racemates and/or salts thereof as such or combined with pharmaceutically acceptable auxiliary materials and the like usually applied in pharmaceuticals to the mammal to be treated.

14. Method according to claim 13 wherein disorder is selected from the group of psychiatrie disorders (such as anxiety, panic disorder, posttraumatic disorder, dépréssion, schizophrenia), neurodevelopmental disorders (such as autism spectrum disorder, obsessive-compulsive disorder, Fragile X syndrome), cognitive disorders, epilepsy, spasticity, sceletal muscle rigidity, spinal cord injury, multiple sclerosis, amyotrophie latéral sclerosis, cérébral palsy, essential tremor, pain (neuropathie, viscéral, osteoarthritic), substance abuse (cocaïne, nicotine, alcohol), obesity, binge eating, asthma, cough, urinary incontinence, gastroesophageal reflux disease, transient lower esophageal sphincter relaxation, irritable bowel syndrome.