WO2017052394A1 - Imidazopyridine compounds and their use as 5-ht6 receptor ligands - Google Patents

Abstract

Novel imidazo[4,5-c]pyridine and imidazo[4,5-b]pyridine derivatives of formula (I) as antagonists of 5-HT₆ receptors, particularly for use in the prevention or treatment of schizophrenia, anxiety, depression, maniac depression, epilepsy, obsessive compulsive disorders, mood disorders, migraine, Alzheimer's disease, age related cognitive decline, mild cognitive impairment, sleep disorders, eating disorders, anorexia, bulimia, panic attacks, attention deficit hyperactivity disorder, attention deficit disorder, Parkinson's disease, Huntington's disease, withdrawal from abuse of ***e, ethanol, nicotine or benzodiazepines, pain, neuropathic pain, obesity and type-2 diabetes, functional bowel disorder, Irritable Bowel Syndrome.

Description

Imidazopyridine compounds and their use as 5-HT₆ receptor ligands

Field of the invention

The invention relates to novel imidazo[4,5-c]pyridine and imidazo[4,5-£]pyridine derivatives having pharmacological activity, process for theirs preparation, formulations and their use in the treatment of diseases.

Background and prior art of the invention

Serotonin (5-Hydroxytryptamine; 5-HT) is implicated in diverse physiological and pathophysiological pathways. It mediates its function via activation with specific receptors. Seven types of 5-HT receptors have been identified to date. One of the recent additions to the serotonin receptors superfamily constitute 5-HT₆ subtype. Human 5-HT₆ receptors are positively coupled to adenyl cyclase. They are almost exclusively distributed in the central nervous system (CNS), displaying the highest density in limbic, striatal and cortical regions (Hannon et al.).

The specific localization of 5-HT₆ receptors suggested a role for these sites in memory and cognition (Mitchel et al.). This was further supported by the fact of enhanced cholinergic transmission upon blockade of 5-HT₆ receptors. Positive effects of selective 5-HT₆ antagonists on learning and memory have been found in several animal modes (Upton, N. et al.)

Apart from potential for the treatment of Alzheimer's disease, age related cognitive decline, mild cognitive impairment, neurodegenerative disorders characterized by impaired neuronal growth, 5-HT₆ modulators have been identified as potentially useful in the treatment or prophylaxis of attention deficit hyperactivity disorder (ADHD), schizophrenia, behavioral disorders: anxiety, depression, maniac depression, obsessive compulsive disorders, mood disorders, panic attacks, (several antipsychotic and antidepressant drugs display high affinity for 5-HT₆ receptors), Parkinson's disease, epilepsy, treatment of diseases associated with neurodegeneration, withdraw from drug abuse such as ***e, ethanol, nicotine and benzodiazepines, and pain. 5-HT₆ ligands are also expected to be useful in the treatment or prophylaxis of obesity, and type-2 diabetes.

The progress in development of 5-HT6 modulators has been comprehensively reviewed by Holenz et al, Ivachtchenko et al, and recently by Benjamu et al . One of the major class of compounds with enhanced affinity and selectivity for 5-HT6 receptors is represented by indole-like derivatives. Among them, 4-piperazinyl-l-arylsulfonylindoles were reported in US 2003/0045527 Al, US 2005/0176705 Al, and US 2005/0256106 Al). Additionally, 4- piperazinyl-l-aiylsulfonylbenzimidazoles were disclosed in US 2010/0120779 Al .

The goal of the present invention relates to providing potent and selective 5-HT₆ modulators based on lH-imidazo[4,5 -£]pyridine and lH-imidazo[4,5 -c]pyridine scaffold, as compounds useful for the treatment of CNS disorders.

Within the entire group of imidazopyridine derivatives, lH-imidazo[4,5 -c]pyridines behaved as potent anti-HCV agents, A2A adenosine receptor antagonists, and protein kinase B inhibitors; or displayed antitumor, and anti-hypertensive activities. On the other hand 1H- imidazo[4,5 -£]pyridines showed anticancer, antimalarial, antifungal, antiviral, or anticonvulsant properties (Lemrova et al., 2014).

Recently, Lemrova et al. reported on a synthesis of imidazo[4,5-£]pyridine and imidazo[4,5-c]pyridine derivatives of general formula (XIII) (Lemrova et al, 2014).

imidazo[4,5-Jb]pyridines imidazo[4,5-c]pyridines

Compounds disclosed therein carried a hydrogen, alkyl or benzyl as Ri substituent in imidazo[4,5-£]pyridines, and morpholine or piperidine as R4, R5 substituents in imidazo[4,5- cjpyridine. Generally alkyl, hydroxyalkyl, amidealkyl moieties were reported as R3 in both chemotypes.

Disclosure of the invention

A structurally novel class of compounds has now been found which display high affinity for 5-HT₆ receptors. Compounds capable selectively modulating 5-HT₆ receptors may be antagonists or inverse agonists.

General terms used in the description of compounds herein disclosed bear their usual meanings. The term alkyl as used herein denotes a univalent saturated branched or straight hydrocarbon chain. Unless otherwise stated such chains can contain from 1 to 5 carbon atoms. Representative of such alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl and structural isomers thereof. The given moiety is defined as Ci-salkyl.

The term 'aryl' embraces monocyclic or fused carbocyclic aromatic group. The term 'heteroaryl' embraces monocyclic or fused bicyclic aromatic group having at least one heteroatom as a ring atom. Said heteroatoms are selected from N, O, S atoms. Examples of heteroaryl group include but not limited to furyl, thienyl, pyrroryl, oxazolyl, thiazolyl, imidazolyl, thiazolyl, triazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pirymidinyl, pyrazinyl, 1,3,5-triazinyl, phenyl, lH-indazol-7-yl, lH-indazol-6-yl, lH-indol-2-yl, lH-indol- 3-yl, lH-indol-6-yl, lH-indol-7-yl, isoindolyl, l-benzofuran-2-yl, l-benzofuran-3-yl, indanyl, indenyl, l-benzothien-3-yl, l-benzothien-2-yl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, 1,8-naphthyridinyl, naphthyl, azulenyl.

'Halo' or 'Halogen' means chloro, fluoro, bromo or iodo.

The term 'substituted' means that the specified group or moiety bears one or more substituents. Where any group may carry multiple substituents, and a variety of possible substituents is provided, the substituents are independently selected, and need not to be the same. The term 'unsubstituted' or when substitution is not indicated means that the specified group bears no substituents others than H atoms.

Throughout the description and the claim of the specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.

The invention relates to a compound of formula (I), or a tautomer, stereoisomer, enantiomer, N-oxide, a pharmaceutically acceptable salt, hydrate or solvate thereof:

wherein:

- A¹ and A² are different and selected from nitrogen or carbon atom;

- Ri represents H or C1-C3 alkyl, preferably Ri represents H or methyl;

- R₂ represents hydrogen, an unsubstituted C1-C5 alkyl, an C1-C5 alkyl substituted with one or more halogen atoms, hydroxyl, a branched C1-C5 alkyl, a 5 to 6 membered aryl or a 5 to 6 membered heteroaryl, optionally substituted with one or more substituents selected from C1-C2 alkyl, one or more halogen atoms, C1-C2 alkoxy, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide, preferably R₂ represents hydrogen, an unsubstituted C1-C5 alkyl, a 6 membered aryl, a 6 membered aryl substituted with halogen atom or C1-C2 alkoxy or 5 membered heteroaryl;

- T represents -CH₂- , -S0₂- or C1-C2 alkyl linking group substituted with R₃; - R₃ represents a 5 to 6 membered unsubstituted aryl, a 8 to 10 membered biaryl, a 5 to 6 membered heteroaryl, a 8 to 10 membered heteroaryl, optionally substituted with one or more substituents selected from C1-C3 alkyl, an C1-C3 alkyl substituted with one or more halogen atoms, C1-C3 alkoxy, C2-C4 alkenyl, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide, preferably R₃ represents a 6 membered aryl or heteroaryl, a 6 membered aryl substituted with one or more halogen atoms, C1-C2 alkoxy or an C1-C3 alkyl substituted with one or more halogen atoms.

Preferably, A¹, A², Ri, R₂ and R₃ are as defined above and T represents -CH₂-, -CH₂-CH₂-or -CH(CH₃)-.

Also preferably, Ri, R₂ and R₃ are as defined above, A¹ is carbon, A² is nitrogen and T represents -S0₂- .

The invention particularly relates to a compound of the general formula (I) or a tautomer, stereoisomer, N-oxide or a pharmacologically acceptable salt, hydrate or solvate of any of the foregoing, wherein:

- and A² are selected from the group comprising nitrogen and carbon atoms, whereby one of A¹ and A² represents nitrogen atom and the another one of A¹ and A² represents carbon atom,

- Ri represents independently H or Ci-C₃alkyl,

- R₂ represents hydrogen, an unsubstituted alkyl(Ci-C₅) group, an alkyl(Ci-C₅) group substituted with one or more halogen atoms, hydroxyl, a branched alkyl (C₁-C5) group, unsubstituted aryl (5-6 membered), heteroaryl (5-6 membered), optionally substituted with one or more substituents selected from alkyl(Ci-C₂) group, one or more halogen atoms, alkoxy(Ci-C₂) group, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide,

- T represents CH₂

- R₃ represents unsubstituted aryl (5-6 membered), biaryl (8-10 membered), heteroaryl (5-6 membered), heteroaryl (8-10 membered), optionally substituted with one or more substituents selected from alkyl(Ci-C₃) group, an alkyl(Ci-C₃) group substituted with one or more halogen atoms, alkoxy(Ci-C₃) group, alkenyl(C₂-C4), halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide.

The invention particularly relates to a compound of the general formula (I) or a tautomer, stereoisomer, N-oxide or a pharmacologically acceptable salt, hydrate or solvate of any of the foregoing, wherein: - A¹ is carbon and A² is nitrogen,

- Ri represents independently H or Ci-C₃alkyl,

- R-2 represents hydrogen, an unsubstituted alkyl(Ci-C₅) group, an alkyl(Ci-C₅) group substituted with one or more halogen atoms, hydroxyl, a branched alkyl (C₁-C5) group, unsubstituted aryl (5-6 membered), heteroaryl (5-6 membered), optionally substituted with one or more substituents selected from alkyl(Ci-C₂) group, one or more halogen atoms, alkoxy(Ci-C₂) group, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide,

- T represents S0₂

- R3 represents unsubstituted aryl (5-6 membered), biaryl (8-10 membered), heteroaryl (5-6 membered), heteroaryl (8-10 membered), optionally substituted with one or more substituents selected from alkyl(Ci-C3) group, an alkyl(Ci-C3) group substituted with one or more halogen atoms, alkoxy(Ci-C3) group, alkenyl(C2-C4), halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide.

The invention relates to racemates, as well as the individual stereoisomers of the compounds having formula (I).

The compounds of the invention of formula (I), as well as pharmacologically acceptable salts thereof, display affinity for 5-HT₆ receptor and behave as antagonists or inverse agonists and as such are useful in treating and preventing diseases, disorders or conditions involving 5-HT₆ receptors, or treatable by manipulation of those receptors. Thus one aspect of the invention provides a method for the treatment, control or prevention of such diseases, disorders or conditions in a mammal which comprises administering to such mammal a therapeutically effective amount of a compound of formula I. The diseases, disorders or conditions for which the compounds of the present invention are useful in treating or preventing include, but are not limited to: schizophrenia, anxiety, depression, maniac depression, epilepsy, obsessive compulsive disorders, mood disorders, migraine, Alzheimer's disease, age related cognitive decline, mild cognitive impairment, sleep disorders, eating disorders, anorexia, bulimia, panic attacks, attention deficit hyperactivity disorder, attention deficit disorder, Parkinson's disease, Huntington's disease, withdrawal from abuse of ***e, ethanol, nicotine or benzodiazepines, pain, neuropathic pain, obesity and type-2 diabetes, functional bowel disorder, Irritable Bowel Syndrome.

Other embodiments of the invention include: - pharmaceutical compositions for treating disorders resulting from disturbance of 5- HT₆ transmission, the composition comprising a compound of formula (I), prodrugs, pharmaceutically acceptable salts and solvates thereof, and a pharmaceutically acceptable carrier;

- methods of treating a disorder or condition treatable by blocking 5-HT₆ receptors, the method comprising administering to a mammal in need of such treating a compound of formula (XIV) or pharmaceutically acceptable salt thereof;

- pharmaceutical compositions for treating a disorder or condition chosen from the disorders listed herein, the compositions comprising a compound of formula (XIV) or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier;

- methods of antagonizing a 5-HT₆ receptor that comprises administering to a subject in need thereof, an effective amount of a compound.

The invention also provides the use of a compound or salt according to formula (I) for the manufacture of medicament. Thus, the subject of the invention is a compound as defined in above for its use in the manufacture of a medicament.

Next subject of the invention is a compound as defined above for its use in the prevention or treatment of diseases, disorders or conditions resulting from disturbance of 5- HT₆ transmission.

Further subject of the invention is a compound as defined above for its use in the prevention or treatment of schizophrenia, anxiety, depression, maniac depression, epilepsy, obsessive compulsive disorders, mood disorders, migraine, Alzheimer's disease, age related cognitive decline, mild cognitive impairment, sleep disorders, eating disorders, anorexia, bulimia, panic attacks, attention deficit hyperactivity disorder, attention deficit disorder, Parkinson's disease, Huntington's disease, withdrawal from abuse of ***e, ethanol, nicotine or benzodiazepines, pain, neuropathic pain, obesity and type-2 diabetes, functional bowel disorder, Irritable Bowel Syndrome.

The invention further relates to combination therapies wherein a compound of the invention, of a pharmaceutically acceptable salt thereof, or a pharmaceutical composition or formulation comprising a compound of the invention, is administrated concurrently or sequentially or as a combined preparation with another therapeutic agent or agents, for treating one or more of the conditions listed. Such other therapeutic agent(s) may be administrated prior to, simultaneously with, of following the administration of the compounds of the invention. The therapeutic agent or agents used in the combination with the compound of invention relates to the compounds used for treating a disorder or conditions chosen from the disorders listed in the invention, with the mechanism of action that synergistically ameliorate the positive outcomes of therapy.

The compounds of the invention exert 5-HT₆ receptor antagonist properties. This activity of the compounds of the invention is readily demonstrated, for example, using one or more of the assays described herein or known in the art.

The invention also provides methods of preparing the compounds of the invention and the intermediates used in those methods.

The compounds of formula I can be prepared e.g. using the reactions and techniques described below. Generally, compounds described in the scope of this patent application can be synthesized by the route described in Scheme 1 and the Examples.

Scheme 1. Synthesis of examples 1-54. Symbol PG refers either to common protective group (such as BOC, Boc, Trt) or the system consisted of polymer support and suitable linker for solid-phase synthesis (e.g. Wang resin)

Compounds of formula I can be prepared by solid-phase synthesis:

a) Immobilization of piperazine on Wang resin via carbamate bond with use of two step coupling procedure: 1) reaction of Wang resin with solution of CDI in DCM, 2) reaction of the obtained resin with solution of piperazine in polar aprotic solvents such as DMSO or DMF.

b) Arylation of resin 1 with solution of 2,4-dichloro-3-nitropyridine in aprotic polar solvents such as DMSO, DMF and MP in a presence of a tertiary base such as TEA, DIEA, DBU.

c) Amination of resin 2 with solution of appropriate amine in aprotic polar solvent such as DMSO, DMF or NMP. Alternatively, resin 3 can be obtained by the reaction of 2,4-dichloro-3-nitropyridine with appropriate amine in aprotic polar solvents such as DMSO, DMF and NMP in a presence of a tertiary base such as TEA, DIEA, DBU and subsequent reaction of the intermediate with resin 1 in aprotic polar solvents such as DMSO, DMF and NMP in a presence of a tertiary base such as TEA, DIEA, DBU.

d) Reduction of the nitro group by: 1) solution of tin(II)chloride dihydrate in DMF in a presence of tertiary base such as TEA, DIEA, DBU, 2) solution of sodium dithionate in a presence of potassium carbonate and TBAHS in a two phase system consisted of water and DCM.

e) Reaction of intermediate 4 with solution of the corresponding aldehyde in polar aprotic solvents such as DMF, DMSO or NMP. This reaction is typically performed at temperature above 70 ⁰ C for 24-72 hrs.

f) Reaction of resin 5 with the corresponding sulfonyl halide in aprotic solvents such as MeCN, THF, DCM, DMF, DMSO or their mixtures in a presence of a tertiary base such TEA, DIEA, DBU or phosphazene bases such as BTPP.

g) Treatment of resin 5 or 6 with suitable acid such as TFA, TFMSA or HF in DCM to release the product from the polymer support.

Except for solid-phase synthesis, target compounds can be obtained with application of traditional solution-phase chemistry using suitably N-protected piperazine. The protecting group is typically acid labile, but is not limited to benzyloxycarbonyl (BOC), t- butoxycarbonyl (Boc) or trityl (Trt). All reaction steps leading to final compounds are based on the same reaction conditions as for the solid-phase strategy described above. The final step (cleavage of Boc-protecting group) is performed by reaction with acids such as HC1 or TFA.

Isolation and purification of the compounds and intermediates described herein can be affected, by any suitable separation or purification procedures such as, for example, filtration, extraction, crystallization, column chromatography, preparative low or high-pressure liquid chromatography, or a combination of these procedures. Suitable separation and isolation procedures may be taken from preparation and Examples. However, other equivalent separation or isolation procedures could be used, also.

The compounds of the present invention may contain one asymmetric center and can thus occur as racemates and racemic mixtures or single enantiomers.

Formula (I) shows the structure of the class of compounds without preferred stereochemistry. The independent syntheses of these isomers, or their chromatographic separation may be achieved as known in the art by appropriate modification of the methodology disclosed therein. Their absolute stereochemistry may be determined by the X- ray crystallography of crystalline products or crystalline intermediates, which are derivatized, if necessary, with a reagent containing as asymmetric center of known absolute configuration. The racemic mixture of compounds can be separated directly by chromatographic methods utilizing chiral stationary phases: methods well-known in the art. Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well-known in the art.

Some of the crystalline forms for the compounds may exist as polymorphs: as such intended to belong to the invention. In addition, some of the compounds may form solvates with water (i.e. hydrates), or common organic solvents. Such solvents also fall within the scope of this invention.

The compounds of the invention may also be used as reagents or standards in the biochemical study of neurological function, dysfunction and disease.

Examples of the compounds of the invention are the following:

Example 1 : 3-benzyl-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine.

Example 2: 3-(2-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 3 : 3-(3-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 4: l-(3-chlorobenzyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Example 5: 2-methyl-3-(2-methylbenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 6: 3-(2-Methoxybenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 7: l-(4-fluorobenzyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine.

Example 8: 3-(2-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine.

Example 9: 3-(3-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine.

Example 10: 3-(2-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 11 : 2-ethyl-3-(3-fluorobenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine.

Example 12: 3-(2,5-difluorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]py-ridine. Example 13 : 2-ethyl-3-(3-fluorophenethyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 14: l-(2-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Example 15: 3-(3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 16: 3-(3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 17: 3-(3-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 18: 2-Isopropyl-3-(3-methoxybenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 19: 3-(4-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 20 : 3 -(3 -fluorobenzyl)-2-isopropyl-7-(3 -methylpiperazin- 1 -yl)-3H-imidazo[4, 5- b]pyridine.

Example 21 : (S)-3-(3-fluorobenzyl)-2-isopropyl-7-(3-methylpiperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 22: l-(4-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Example 23 : 2-isopropyl-7-(piperazin-l-yl)-3-(pyridin-4-ylmethyl)-3H-imidazo[4,5- b]pyridine.

Example 24 : 3 -( 1 -(3 -fluorophenyl)ethyl)-2-isopropyl-7-(piperazin- 1 -yl)-3H-imidazo[4,5- b]pyridine.

Example 25: (S)-3-(l-(3-fluorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 26: (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 27: (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 28: 3-(2-chlorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 29: 3-(3-methylbenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 30: 3-(4-fluorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine

Example 31 : 3-(2-chlorobenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 32: 3-(3-methylbenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 33 : 3-(3-methoxybenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 34: 3-(3-chlorobenzyl)-7-(piperazin-l-yl)-2-(thiophen-2-yl)-3H-imidazo[4,5- b]pyridine. Example 35: 7-(piperazin-l-yl)-2-(thiophen-2-yl)-3-(3-(trifluoromethyl)benzyl)-3H- imidazo[4,5-b]pyridine.

Example 36: 3-benzyl-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Example 37: 3-(2-fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 38: 3-(3-chlorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine.

Example 39: 3 -(3 -fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin- 1 -yl)-3H-imidazo[4, 5- b] pyridine.

Example 40: 2-methyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Example 41 : l-((3-fluorophenyl)sulfonyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c] pyridine.

Example 42 : 2-ethyl- 1 -((3 -methylphenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine.

Example 43 : l-((4-aminophenyl)sulfonyl)-2-ethyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

Example 44: 2-ethyl-l-((3-fluorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

Example 45: 2-isopropyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Example 46: 3-((3-chlorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- c]pyridine.

Example 47 : 1 -((3 -fluorophenyl)sulfonyl)-2-i sopropyl-4-(3 -methylpiperazin- 1 -yl)- 1 H- imidazo[4,5-c]pyridine.

Example 48 : 2-isopropyl- 1 -((3 -methoxyphenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine.

Example 49: 3-((4-fluorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- c]pyridine.

Example 50: l-((3-chlorophenyl)sulfonyl)-2-cyclopentyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

Example 51 : 2-butyl- 1 -((3 -chlorophenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine.

Example 52: 2-butyl-l-((4-fluorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

Example 53 : 2-butyl-l-((4-methoxyphenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

Example 54: l-((3-chlorophenyl)sulfonyl)-2-(4-methoxyphenyl)-4-(piperazin-l-yl)-lH- imidazo[4,5-c]pyridine.

The compounds of the present invention contain at least one asymmetric center and thus occur as racemates and racemic mixtures or single enantiomers. Also, mixture of enantiomers being enriched in one of enantiomers are available by the method of the invention.

N-oxides of the compounds mentioned above belong to the invention. Tertiary amines may or may not give rise to N-oxide metabolites. The extent to what N-oxidation takes place varies from trace amounts to a near quantitative conversion. N-oxides may be more active than their corresponding tertiary amines, or less active. While N-oxides can easily be reduced to their corresponding tertiary amines by chemical means, in human body this happens to varying degrees. Some N-oxides undergo nearly quantitative reductive conversion to the corresponding tertiary amines, in other cases is a mere trace reaction, or even completely absent.

The compound of the invention may exist in various forms, for example polymorphs, solvates and amorphous forms. Some of the crystalline forms of the compounds may exist as polymorphs: as such intended to belong to the invention. In addition, some of the compounds may form solvates with water (i.e. hydrates), or common organic solvents. Such hydrates and solvates are also encompassed by the scope of present invention. Examples thereof include 1/10 hydrates hydrate, 1/4 hydrate, monohydrate, dihydrochloride, dihydrate, dihydrochloride 3/2 hydrate, and the like. Amorphous forms are non-crystalline materials with no long range order, and generally do not give a distinctive powder X-ray diffraction pattern.

Accordingly, the invention provides a compound according of the formula (I) or pharmaceutically acceptable salt thereof for use in the therapy in treating CNS diseases, disorders or conditions associated with disturbances of the serotoninergic systems.

The term "pharmaceutically acceptable salt" refers to those salts that are, within the scope medical judgment, suitable for use in contact with tissues of humans and lower animals without undue toxicity, irritation, allergic response, and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well-known in the art. They can be prepared in situ when finally isolating and purifying the compounds of the invention, or separately by reacting them with pharmaceutically acceptable non-toxic acids, including inorganic or organic acids (Berge, 1977). The "free base" form may be regenerated by contacting the salt with a base, and isolating the parent compound in the conventional matter. The parent form of the compound differs from the various salt forms in certain physical properties, such as solubility in polar solvents, but otherwise the salts are equivalent to the parent form of the compound for the purposes of the present invention. The term "treatment" as used herein refers to any treatment a mammalian, for example human condition or disease, and includes: (i) inhibiting the disease or condition, i.e., arresting its development, (ii) relieving the disease or condition, i.e.; causing the condition to regress, or (iii) stopping the symptoms of the disease.

As used herein, the term "medical therapy" intendeds to include prophylactic, diagnostic and therapeutic regimens carries out in vivo or ex vivo on humans or other mammals.

Said psychotropic diseases, disorders or conditions are selected from the group comprising schizophrenia, anxiety, depression, maniac depression, obsessive compulsive disorders, mood disorders, migraine, aggression, sleep disorders, Alzheimer's disease, age related cognitive decline, mild cognitive impairment, eating disorders, anorexia, bulimia, panic attacks, attention deficit hyperactivity disorder, attention deficit disorder, autism, Parkinson's disease, Huntington's disease, pain, neuropathic pain, withdrawal from abuse of ***e, ethanol, nicotine or benzodiazepines.

The invention further relates to combination therapies wherein a compound of the invention, of a pharmaceutically acceptable salt thereof, or a pharmaceutical composition or formulation comprising a compound of the invention, is administrated concurrently or sequentially or as a combined preparation with another therapeutic agent or agents, for treating one or more of the conditions listed. Such other therapeutic agent(s) may be administrated prior to, simultaneously with, of following the administration of the compounds of the invention.

The therapeutic agent or agents used in the combination with the compound of invention relates to the compounds used for treating a disorder or conditions chosen from the disorders listed in the invention, with the mechanism of action that synergistically ameliorate the positive outcomes of therapy.

The term "therapeutically effective amount" as used herein refers to an amount of a therapeutic agent to treat a condition treatable by administrating a composition of the invention. That amount is the amount sufficient to exhibit a detectable therapeutic or ameliorative response in as tissue system, animal or human. It is not useful to specify an exact effective amount in advance.

With the context of this application, the term "combination preparation" comprises both true combinations, meaning a compound of formula (I) and one or more other medicaments physically combined in one preparation such as a tablet or injection fluid, comprising a compound of formula (I) and one or more other medicaments in separate dosage forms, together with instruction for use, optionally with further means for facilitating compliance with the administration of the component compounds, e.g. label or drawings. With true combinations, the pharmacotherapy by definition is simultaneous.

While it may be possible for the compounds of formula (I) to be administered as the raw chemical, it is preferable to present them as a 'pharmaceutical composition'. According to a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I), or pharmaceutically acceptable salt or solvate thereof, together with one or more pharmaceutically acceptable carriers thereof or diluent/diluents, and optionally one or more other therapeutic ingredients. The carrier/carriers) must be 'acceptable' in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The term "composition" as used herein encompasses a product comprising specified ingredients in predetermined amount or proportions, as well as any product that results, directly or indirectly, from combining specified ingredients in specified amounts. In relation to pharmaceutical compositions, this term encompasses a product comprising one or more active ingredients, and an optimal carrier comprising inert ingredients, as well as any product that results, directly or indirectly from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interaction of one or more of the ingredients. In general, pharmaceutical compositions are prepared by uniformly and intimately bringing the active ingredients into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product into desired formulation. The pharmaceutical composition includes enough of the active object compound to produce the desired effect upon the progress or condition of disease. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By "pharmaceutically acceptable" it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The typical daily dose of the active ingredients varies within a wide range and will depend on various factors such as the relevant indication, the route of administration, the age, weight and sex of the patient and may be determined by a physician. In general, total daily dose administration to a patient a single or individual doses, may be in amounts, for example from 0.001 to 10 mg/kg body weight daily, and more usually 0.01 to 1000 mg per day, of total active ingredients.

The invention also provides the use of a compound or salt according to formula (I) for the manufacture of medicament.

The chemical names of the substances were generated using ChemBioDraw Ultra 12.0.

Abbreviations

General analytical methods

Solvents and chemicals were purchased from Aldrich (Milwaukee, IL, www.sigmaaldrich.com), Acros (Geel, Belgium, www.acros.cz) and Fisher (Pittsburgh, PA, www.fishersci.com). Wang resin (100-200 mesh, 1% DVB, 1.0 mmol/g) and 4-(4-Formyl-3- methoxyphenoxy)butyric acid were obtained from AAPPTec (Louisville, KY, www.aapptec.com). Synthesis was carried out on Domino Blocks in disposable polypropylene reaction vessels (Torviq, Niles, MI, www.torviq.com). Labquake Tube Rotator (Therm olyne, Dubuque, IA, www.barnsteadthermolyne.com) was used for gentle but efficient tumbling of resin slurry.

All reactions were carried out at ambient temperature (21 °C) unless stated otherwise. The volume of wash solvent was 10 mL per 1 g of resin. For washing, resin slurry was shaken with the fresh solvent for at least 1 min before changing the solvent. After adding a reagent solution, the resin slurry was manually vigorously shaken to break any potential resin clumps. Resin-bound intermediates were dried by a stream of nitrogen for prolonged storage and/or quantitative analysis. For the LC/MS analysis a sample of resin (~5 mg) was treated by TFA in DCM, the cleavage cocktail was evaporated by a stream of nitrogen, and cleaved compounds extracted into 1 mL of MeOH.

The LC/MS analyses were carried out on UHPLC-MS system consisting of UHPLC chromatograph Acquity with photodiode array detector and single quadrupole mass spectrometer (Waters), using X-Select C18 column at 30 °C and flow rate of 600 μL/min. Mobile phase was (A) 0.01 M ammonium acetate in water, and (B) acetonitrile, linearly programmed from 10% to 80% B over 2.5 min, kept for 1.5 min. The column was re- equilibrated with 10%) of solution B for 1 min. The ESI I source operated at discharge current of 5 μΑ, vaporizer temperature of 350 °C and capillary temperature of 200 °C.

Purification was carried out on CI 8 reverse phase column 19 x 100 mm, 5 μπι particles, gradient was formed from 10 mM aqueous ammonium acetate and acetonitrile, flow rate 15 mL/min.

All 1H and ¹³C MR experiments except two were performed with using Jeol ECX-500SS at magnetic field strengths of 11.749 T corresponding to 1H and ¹³C resonance frequencies of 500.16 MHz and 125.77 MHz at ambient temperature (25 °C). Chemical shifts δ are reported in ppm and coupling constants Jin Hz.

Working Examples :

Intermediate 1. Wang resin (loading lmmol/g, 400 mg) was washed 3 x with dichloromethane (DCM). Solution of carbonyldiimidazole CDI (2 mmol) and pyridine (2 mmol) in 4 mL DCM was added and the resin slurry was shaken at room temperature (rt) for 2 h. Then the resin was washed 3 x with DCM and a solution of piperazine (2 mmol) in 4 mL DCM was added. Resin slurry was shaken at rt overnight (on), then washed with DMF and DCM (3 x).

Intermediate 2: Intermediate 1 was washed with DCM and DMSO (3 ^χ), and a solution of 2,4-dichloro-3-nitropyridine (2 mmol; 960) and an eq. of DIEA (2 mmol) in DMSO (4 mL) was added. The resin slurry was shaken for 16 hours. After the reaction, the resin was washed with DMF and DCM (3 x).

Intermediate 3: Intermediate 2 was washed with DCM and DMSO (3 ^χ). A 10%. solution of amine in DMSO (4 mL) was added to the resin, and the resin slurry was shaken at room temperature overnight. Subsequently, the resin was washed with DMSO and DCM (3 x). Intermediate 4: Intermediate 3 was washed with DCM (3 ^χ), and DCM (4 mL) was added. Then, a solution of sodium dithionite (840 mg; 4 mmol), potassium carbonate (760 mg; 5.6 mmol) and tetrabutylammonium hydrogen sulfate (136 mg; 0.4 mmol) in water (8 mL) was prepared and quickly added to the resin with DCM. The resin slurry was shaken overnight and washed with water/DCM (1/1), DMF and DCM (3 x).

Intermediate 5: Intermediate 4 was washed with DCM and DMSO (3 x), and 0.5 M aldehyde in DMSO (5 mL) was added. The resin was shaken at 80°C for 48 hours. After the reaction, the resin was washed with DMSO and DCM (3 ^χ).

Intermediate 6: Intermediate 5 was washed with DCM (3 x), and 0.5 M sulfonyl chloride in DCM (5 mL) with equivalent of BTPP was added. The resin was shaken at 50°C for 24 hours. After the reaction, the resin was washed with DCM (3 x).

Example 1-54: Intermediate 5 was treated with 50% TFA in DCM (4 mL) for 1 h. The cleavage cocktail was collected, and the resin was washed with 50% TFA in DCM (3 ^χ). The liquid phases were combined and evaporated under a stream of nitrogen. The resulting residue was dissolved in MeOH and purified by semipreparative HPLC. The final compounds were obtained with purity > 95% (UPLC) in 46 % yield.

Examples of the compounds according to the invention:

Example 1 : 3-benzyl-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 308.3; 1H MR (500 MHz, DMSO-d₆) δ ppm 2.38 (s, 3 H) 2.77 - 2.83 (m, 4 H) 3.69 - 3.75 (m, 4 H) 5.37 (s, 2 H) 6.45 (d, J=5.73 Hz, 1 H) 7.09 - 7.14 (m, 2 H) 7.19 - 7.24 (m, 1 H) 7.25 - 7.30 (m, 2 H) 7.88 (d, J=5.73 Hz, 1 H).

Example 2: 3-(2-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Pale yelow solid, MS [M-H]⁺ = 342.2; 1H NMR (500 MHz, DMS0 ) δ ppm 2.37 (s, 3 H) 2.78 - 2.83 (m, 4 H) 3.73 - 3.77 (m, 4 H) 5.43 (s, 2 H) 6.38 - 6.43 (m, 1 H) 6.46 (d, J=5.73 Hz, 1 H) 7.1 [3 - 7.20 (m, 1 H) 7.24 - 7.30 (m, 1 H) 7.49 (s, 1 H) 7.82 (d, J=5.73 Hz, 1 H).

Example 3 : 3-(3-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Pale yellow solid, MS [M-H]⁺ = 342.3; 1H NMR (500 MHz, DMSO-d₆) δ ppm 2.39 (s, 3 H) 2.80 - 2.85 (m, 4 H) 3.73 - 3.78 (m, 4 H) 5.38 (s, 2 H) 6.47 (d, J=5.73 Hz, 1 H) 7.03 - 7.07 (m, 1 H) 7.21 (s, 1 H) 7.28 - 7.33 (m, 2 H) 7.89 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, DMSO-d₆) δ ppm 14.40, 22.05, 44.56, 45.78, 48.59, 102.48, 123.46, 126.04, 127.24, 127.99, 131.18, 133.79, 140.32, 144.58, 147.37, 147.86, 149.54, 172.90.

Example 4: l-(3-chlorobenzyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. MS [M-H]⁺ = 342.3; 1H NMR (500 MHz, DMSO- ) d ppm 2.43 (s, 3 H) 2.82 (br. s., 4 H) 3.94 - 3.99 (m, 4 H) 5.40 (s, 2 H) 6.82 (d, J=5.73 Hz, 1 H) 6.94 - 6.98 (m, 1 H) 7.15 (s, 1 H) 7.30 - 7.33 (m, 2 H) 7.73 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, DMSO-d₆) δ ppm 13.89, 23.09, 45.62, 46.29, 46.89, 98.03, 125.76, 127.02, 128.14, 131.30, 133.92, 139.76, 139.98, 141.77, 148.99, 151.17, 173.50

Example 5: 2-methyl-3-(2-methylbenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 322.2.

Example 6: 3-(2-Methoxybenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 338.2; 1H MR (400 MHz, DMS0 ) δ ppm 2.37 (s, 3 H) 2.85 (br. s., 4 H) 3.74 - 3.80 (m, 4 H) 3.84 (s, 3 H) 5.29 (s, 2 H) 6.41 - 6.47 (m, 2 H) 6.75 (d, J=1.37 Hz, 1 H) 7.01 (d, J=8.24 Hz, 1 H) 7.16 - 7.24 (m, 1 H) 7.83 (dd, J=5.72, 1.15 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 14.17, 40.94, 45.47, 48.35, 55.96, 102.38, 111.28, 120.92, 123.65, 125.19, 127.05, 129.11, 144.39, 147.26, 148.29, 149.72, 156.74.

Example 7: l-(4-fluorobenzyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. White solid, MS [M-H]⁺ = 326.3; 1H NMR (500 MHz, OMSO-d₆) δ 2.43 (s, 3 H) 2.74 - 2.82 (m, 4 H) 3.89 - 3.95 (m, 4 H) 5.36 (s, 2 H) 6.81 - 6.84 (m, 1 H) 7.12 (d, J=7.45 Hz, 4 H) 7.69 - 7.73 (m, 1 H).

Example 8: 3-(2-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Yellow solid, MS [M-H]⁺ = 356.2; 1H NMR (500 MHz, OMSO-d₆) δ ppm 1.16 (t, J=7.45 Hz, 3 H) 2.69 (q, J=7.45 Hz, 2 H) 2.81 - 2.88 (m, 4 H) 3.76 - 3.83 (m, 4 H) 5.43 (s, 2 H) 6.39 (d, J=7.45 Hz, 1 H) 6.47 (d, J=5.73 Hz, 1 H) 7.16 (t, J=7.45 Hz, 1 H) 7.26 (t, J=7.73 Hz, 1 H) 7.49 (d, J=8.02 Hz, 1 H) 7.83 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 11.94, 20.77, 22.53, 42.86, 45.79, 102.55, 123.55, 127.47, 128.17, 129.58, 130.0, 131.79, 135.02, 144.65, 147.55, 149.59, 152.23, 173.20.

Example 9: 3-(3-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Pale yellow solid, MS [M-H]⁺ = 356.2; 1H NMR (500 MHz, OMSO-d₆) δ ppm 1.12 - 1.18 (m, 3 H) 2.73 (q, J=7.45 Hz, 2 H) 2.89 - 2.97 (m, 4 H) 3.81 - 3.89 (m, 4 H) 5.40 (s, 2 H) 6.51 (d, J=5.73 Hz, 1 H) 7.03 (dd, J=6.59, 2.00 Hz, 1 H) 7.19 (s, 1 H) 7.28 - 7.31 (m, 2 H) 7.91 (d, J=5.73 Hz, 1 H)

Example 10: 3-(2-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 368.3; 1H NMR (500 MHz, DMS0 ) δ ppm 1.11-1.18 (m, 6 H) 2.82 (d, J=4.01 Hz, 4 H) 3.12 (quin, J=6.73 Hz, 1 H) 3.76 (d, J=4.58 Hz, 4 H) 5.45 (s, 2 H) 6.46 (d, J=5.73 Hz, 1 H) 6.70 - 6.76 (m, 1 H) 7.04 (t, J=7.45 Hz, 1 H) 7.17-7.23 (m, 1 H) 7.25 - 7.31 (m, 1 H) 7.86 (d, J=5.73 Hz, 1 H).

Example 11 : 2-ethyl-3-(3-fluorobenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 340.2. Example 12: 3-(2,5-difluorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]py-ridine. White solid, MS [M-H]⁺ = 358.4; 1H NMR (500 MHz, DMS0 ) δ ppm 1.16 (t, J=7.45 Hz, 3 H) 2.75 (q, J=7.45 Hz, 2 H) 3.25 (br. s., 4 H) 4.39 (br. s., 4 H) 5.75 (br. s., 2 H) 6.91 (d, J=4.01 Hz, 2 H) 7.17 - 7.25 (m, 2 H) 7.26 - 7.32 (m, 1 H) 7.34 (d, J=5.73 Hz, 1 H) 7.44 (br. s., 1 H) 8.09 (d, J=6.87 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 11.38, 20.45, 41.82, 42.81, 45.09, 103.06, 115.82, 116.02, 117.04, 117.89, 118.08, 122.74, 148.72, 153.70, 155.62, 157.56, 157.70, 159.61.

Example 13 : 2-ethyl-3-(3-fluorophenethyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 354.3; 1H NMR (400 MHz, OMSO-d₆) δ ppm 1.18 (s, J=6.87 Hz, 3 H) 2.82 - 2.91 (m, 4 H) 3.20 (q, J=6.89 Hz, 2 H) 3.76 - 3.84 (m, 4 H) 4.10 (t, J=7.10 Hz, 2 H) 5.21 (t, J=7.15 Hz, 2 H) 6.48 (d, J=5.95 Hz, 1 H) 6.88 (d, J=7.79 Hz, 1 H) 6.94 (dt, J=10.08, 1.83 Hz, 1 H) 7.01 - 7.08 (m, 1 H) 7.31 (td, J=7.90, 6.18 Hz, 1 H) 7.90 (d, J=5.95 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 22.71, 27.45, 41.21, 44.22, 45.51, 48.41, 105.59, 113.41, 114.25, 114.28, 114.99, 123.87, 131.41, 131.88, 141.18, 141.28, 144.87, 147.95, 149.11, 155.82, 161.11, 163.89.

Example 14: l-(2-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. White solid, MS [M-H]⁺ = 368.3; 1H NMR (500 MHz, OMSO-d₆) δ ppm 1.14 - 1.21 (m, 6 H) 2.81 (d, J=4.01 Hz, 4 H) 3.21 (dt, 7=13.60, 6.66 Hz, 1 H) 3.96 (d, 7=4.01 Hz, 4 H) 5.46 (s, 2 H) 6.72 - 6.80 (m, 2 H) 7.06 - 7.11 (m, 1 H) 7.17 - 7.24 (m, 1 H) 7.27 - 7.34 (m, 1 H) 7.68 - 7.72 (m, 1 H).

Example 15: 3-(3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Pale yellow solid, MS [M-H]⁺ = 384.3; 1H NMR (500 MHz, OMSO-d₆) δ ppm 1.09 - 1.17 (m, 6 H) 2.82 - 2.90 (m, 4 H) 3.13 (quin, 7=6.73 Hz, 1 H) 3.74 - 3.82 (m, 4 H) 5.43 (s, 2 H) 6.48 (d, 7=5.73 Hz, 1 H) 7.00 (d, 7=5.73 Hz, 1 H) 7.18 (s, 1 H) 7.27 - 7.31 (m, 2 H) 7.89 (d, 7=5.73 Hz, 1 H). ¹³C NMR (125 MHz, DMS0 ) δ ppm 21.98, 26.45, 44.22, 45.65, 48.53, 102.55, 123.50, 125.81, 127.05, 127.90, 131.12, 133.73, 140.77, 144.69, 147.52, 149.41, 155.70, 172.76.

Example 16: 3-(3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 370.2.

Example 17: 3-(3-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 354.2; 1H NMR (400 MHz, DMS0 ) δ ppm 1.14 (d, 7=6.87 Hz, 6 H) 2.82 - 2.91 (m, 4 H) 3.13 (dt, 7=13.74, 6.87 Hz, 1 H) 3.76 - 3.84 (m, 4 H) 5.44 (s, 2 H) 6.48 (d, 7=5.95 Hz, 1 H) 6.88 (d, 7=7.79 Hz, 1 H) 6.94 (dt, 7=10.08, 1.83 Hz, 1 H) 7.01 - 7.08 (m, 1 H) 7.31 (td, J=7.90, 6.18 Hz, 1 H) 7.90 (d, J=5.95 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-de) δ ppm 21.96, 26.47, 44.34, 45.45, 48.35, 105.56, 113.93, 114.15, 114.64, 114.85, 123.13, 131.21, 131.28, 141.11, 141.17, 144.68, 147.47, 149.46, 155.76, 161.51, 163.54. Example 18: 2-Isopropyl-3-(3-methoxybenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 366.2; 1H NMR (400 MHz, DMSO- ) δ ppm 1.14 (d, J=6.64 Hz, 6 H) 2.86 (br. s., 4 H) 3.07 - 3.16 (m, 1 H) 3.64 (s, 3 H) 3.78 (d, J=4.12 Hz, 4 H) 5.38 (s, 2 H) 6.47 (d, J=5.72 Hz, 1 H) 6.57 (d, J=7.79 Hz, 1 H) 6.67 - 6.71 (m, 1 H) 6.78 (dd, J=8.24, 2.52 Hz, 1 H) 7.17 (t, J=8.01 Hz, 1 H) 7.89 (d, J=5.72 Hz, 1 H). ). ¹³C NMR (125 MHz, OMSO-de) δ ppm 21.99, 26.50, 31.22, 44.68, 45.50, 48.49, 55.51, 102.46, 112.86, 113.22, 119.13, 126.55, 130.31, 139.80, 155.58, 147.48, 149.50, 155.86, 159.90.

Example 19: 3-(4-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Pale yellow solid, MS [M-H]⁺ = 384.5; 1H NMR (500 MHz, DMS0 ) δ ppm 1.13 (d, J=6.87 Hz, 6 H) 2.82 (br. s., 4 H) 3.11 (dt, J=13.32, 6.80 Hz, 1 H) 3.75 (br. s., 4 H) 5.41 (s, 2 H) 6.46 (d, J=5.73 Hz, 1 H) 7.10 (d, J=8.59 Hz, 2 H) 7.33 (d, J=8.59 Hz, 2 H) 7.88 (d, J=5.73 Hz, 1 H).

Example 20 : 3 -(3 -fluorobenzyl)-2-isopropyl-7-(3 -methylpiperazin- 1 -yl)-3H-imidazo[4, 5- b]pyridine. White solid, MS [M-H]⁺ = 368.5.

Example 21 : (S)-3-(3-fluorobenzyl)-2-isopropyl-7-(3-methylpiperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 368.5.

Example 22: l-(4-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine.

White solid, MS [M-H]⁺ = 368.3; 1H NMR (500 MHz, DMS0 ) δ ppm 1.20 (d, J=6.87 Hz,

6 H) 2.80 - 2.85 (m, 4 H) 3.22 (dt, J=13.75, 6.87 Hz, 1 H) 3.95 - 4.01 (m, 4 H) 5.44 (s, 2 H)

6.82 (d, J=5.16 Hz, 1 H) 7.07 - 7.12 (m, 2 H) 7.13 - 7.19 (m, 2 H) 7.75 (d, J=5.16 Hz, 1 H).

Example 23 : 2-isopropyl-7-(piperazin-l-yl)-3-(pyridin-4-ylmethyl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 337.3.

Example 24 : 3 -( 1 -(3 -fluorophenyl)ethyl)-2-isopropyl-7-(piperazin- 1 -yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 368.2.

Example 25: (S)-3-(l-(3-fluorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 350.3.

Example 26: (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 384.3.

Example 27: (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 350.3. Example 28: 3-(2-chlorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. Yellow solid, MS [M-H]⁺ = 398.3; 1H MR (500 MHz, OMSO-d₆) δ ppm 0.60 - 0.65 (m, 6 H) 1.51 - 1.60 (m, 2 H) 1.61 - 1.71 (m, 2 H) 2.62 (s, 1 H) 2.90 (br. s., 4 H) 3.84 (d, J=3.44 Hz, 4 H) 5.46 (s, 2 H) 6.50 (d, J=5.73 Hz, 2 H) 7.14 (td, J=7.45, 1.15 Hz, 1 H) 7.25 (td, J=7.73, 1.72 Hz, 1 H) 7.46 - 7.50 (m, 1 H) 7.87 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-de) δ ppm 12.08, 22.51, 27.09, 42.53, 45.13, 48.06, 102.71, 123.88, 128.02, 128.21, 129.70, 129.94, 131.75, 135.19, 144.63, 147.32, 149.32, 154.11, 173.34.

Example 29: 3-(3-methylbenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 378.3; 1H NMR (500 MHz, OMSO-d₆) δ ppm 0.64 (t, J=7.45 Hz, 6 H) 1.53 - 1.68 (m, 4 H) 2.74 - 2.80 (m, 1 H) 2.85 - 2.92 (m, 4 H) 3.78 - 3.84 (m, 4 H) 5.40 (s, 2 H) 6.51 (d, J=5.73 Hz, 1 H) 6.92 (d, J=7.45 Hz, 1 H) 6.99 (s, 1 H) 7.05 (d, J=7.45 Hz, 1 H) 7.14 - 7.19 (m, 1 H) 7.94 (d, J=5.73 Hz, 1 H)

Example 30: 3-(4-fluorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 382.3; 1H NMR (500 MHz, OMSO-d₆) δ ppm 0.58 (t, J=7.16 Hz, 6 H) 1.48 - 1.66 (m, 4 H) 2.76 (ddd, J=8.16, 5.58, 2.86 Hz, 1 H) 2.82 - 2.88 (m, 4 H) 3.73 - 3.82 (m, 4 H) 5.40 (s, 2 H) 6.49 (d, J=5.73 Hz, 1 H) 7.06 - 7.12 (m, 2 H) 7.20 (dd, J=8.59, 5.15 Hz, 2 H) 7.92 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, DMS0 ) δ ppm 12.02, 22.05, 27.41, 44.07, 45.42, 48.38, 102.52, 115.73, 115.90, 123.92, 129.59, 129.66, 134.56, 144.49, 147.36, 149.26, 154.14, 160.97, 162. 91, 172.92.

Example 31 : 3-(2-chlorobenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. Yellow solid, MS [M-H]⁺ = 398.3; 1H NMR (500 MHz, DMSO- ) δ ppm 0.95 (s, 9 H) 2.58 (s, 2 H) 2.82 - 2.91 (m, 4 H) 3.80 - 3.87 (m, 4 H) 5.46 - 5.48 (m, 2 H) 6.41 (dd, J=7.45, 1.15 Hz, 1 H) 6.47 (d, J=5.73 Hz, 1 H) 7.13 (td, J=7.45, 1.15 Hz, 1 H) 7.24 (td, J=7.73, 1.72 Hz, 1 H) 7.48 (dd, J=8.02, 1.15 Hz, 1 H) 7.85 (d, J=5.73 Hz, 1 H).

Example 32: 3-(3-methylbenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 378.3; 1H NMR (500 MHz, DMS0 ) δ ppm 0.94 (s, 9 H) 2.18 (s, 2 H) 2.80 - 2.85 (m, 4 H) 3.77 - 3.82 (m, 4 H) 5.37 (s, 2 H) 6.46 (d, J=5.73 Hz, 1 H) 6.81 (d, J=7.45 Hz, 1 H) 6.91 (s, 1 H) 7.01 (d, J=7.45 Hz, 1 H) 7.10 - 7.15 (m, 1 H) 7.88 (d, 7=5.73 Hz, 1 H)

Example 33 : 3-(3-methoxybenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 394.3; 1H NMR (500 MHz, OMSO-d₆) δ ppm 0.94 (s, 9 H) 2.61 (s, 2 H) 2.84 (br. s., 4 H) 3.64 (s, 3 H) 3.80 (br. s., 4 H) 5.38 (s, 2 H) 6.46 (d, J=5.73 Hz, 1 H) 6.57 (d, J=8.02 Hz, 1 H) 6.67 (s, 1 H) 6.77 (dd, 7=8.31, 2.58 Hz, 1 H) 7.16 (t, J=7.73 Hz, 1 H) 7.88 (d, J=5.73 Hz, 1 H). ¹³C NMR (125 MHz, DMS0 ) δ ppm 29.90, 32.63, 45.02, 45.66, 48.58, 55.52, 102.37, 1 12.88, 1 13.34, 1 19.24, 123.66, 130.27, 139.70, 144.56, 147.28, 149,21, 149.42, 159.90.

Example 34: 3-(3-chlorobenzyl)-7-(piperazin-l-yl)-2-(thiophen-2-yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 410.3; 1H NMR (500 MHz, DMSO- ) δ ppm 3.04 (br. s., 4 H) 3.98 (br. s., 4 H) 5.67 (s, 2 H) 6.39 (d, J=7.45 Hz, 1 H) 6.61 (d, J=5.73 Hz, 1 H) 7.07 - 7.12 (m, 1 H) 7.15 (t, J=7.73 Hz, 1 H) 7.22 (d, J=3.44 Hz, 1 H) 7.28 (t, J=7.73 Hz, 1 H) 7.54 (d, J=8.02 Hz, 1 H) 7.70 (d, 7=5.15 Hz, 1 H) 7.94 (d, 7=5.73 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-de) δ ppm 44.63, 47. 22, 103.39, 124.15, 126.95, 127.68, 128.27, 128.90, 129.73, 129.99, 130.18, 131.62, 132.28, 134.46, 143.65, 145.87, 147.22, 150.09, 172.64.

Example 35 : 7-(piperazin-l-yl)-2-(thiophen-2-yl)-3-(3-(trifluoromethyl)benzyl)-3H- imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 443.2; 1H NMR (500 MHz, OMSO-d₆) δ ppm 2.81 - 2.88 (m, 4 H) 3.79 - 3.87 (m, 4 H) 5.77 (s, 2 H) 6.55 (d, 7=5.73 Hz, 1 H) 7.1 1 (t, 7=4.58 Hz, 1 H) 7.21 (d, 7=8.02 Hz, 1 H) 7.40 - 7.44 (m, 1 H) 7.46 - 7.51 (m, 2 H) 7.58 (d, 7=8.02 Hz, 1 H) 7.68 (d, 7=4.58 Hz, 1 H) 7.94 (d, 7=5.73 Hz, 1 H).

Example 36: 3-benzyl-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine. White solid, MS [M-H]⁺ = 388.3; 1H NMR (500 MHz, DMSO- ) δ ppm 2.80 - 2.86 (m, 4 H) 3.79 - 3.84 (m, 4 H) 5.52 (s, 2 H) 6.54 (d, 7=5.73 Hz, 1 H) 6.92 (d, 7=6.87 Hz, 2 H) 7.13 - 7.23 (m, 3 H) 7.26 - 7.32 (m, 2 H) 7.65 - 7.72 (m, 2 H) 7.96 (d, 7=5.73 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-de) δ ppm 46.04, 46.37, 48.96, 102.70, 1 16.25, 1 16.42, 124.18, 126.75, 127.30, 127.82, 129.15, 131.52, 131.58, 137.84, 145.62, 148.05, 150.19, 162.36, 164.34. Example 37: 3-(2-fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. White solid, MS [M-H]⁺ = 406.2.

Example 38 : 3-(3-chlorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5- b]pyridine. Pale yellow solid, MS [M-H]⁺ = 422.3; 1H NMR (500 MHz, OMSO-de) δ ppm 2.79 - 2.90 (m, 4 H) 3.82 - 3.87 (m, 4 H) 5.51 (s, 2 H) 6.56 (d, 7=6.30 Hz, 1 H) 6.81 - 6.86 (m, 1 H) 7.01 (s, 1 H) 7.23 - 7.27 (m, 2 H) 7.28 - 7.33 (m, 2 H) 7.62 - 7.70 (m, 2 H) 7.96 (d, 7=5.73 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-de) δ ppm 45.83, 48.73, 102.82, 1 16.32, 1 16.49, 124.13, 125.46, 126.80, 127.09, 127.1 1, 127.89, 131.13, 131.55, 131.61, 133.76, 140.29, 145.71, 148.00, 150.07, 162.43, 164.41, 172.82.

Example 39: 3 -(3 -fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin- 1 -yl)-3H-imidazo[4, 5- b]pyridine. White solid, MS [M-H]⁺ = 406.2; 1H NMR (400 MHz, OMSO-de) δ ppm 2.88 (d, 7=4.12 Hz, 4 H) 3.81 - 3.91 (m, 4 H) 5.52 (s, 2 H) 6.56 (d, 7=5.95 Hz, 1 H) 6.71 (s, 1 H) 6.75 - 6.81 (m, 1 H) 6.96 - 7.04 (m, 1 H) 7.30 (t, J=8.70 Hz, 3 H) 7.64 - 7.71 (m, 2 H) 7.97 (d, J=5.95 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 45.42, 48.38, 102.89, 113.63, 113.85, 114.64, 114.85, 116.29, 116.50, 122.78, 124.16, 127.12, 131.23, 131.31, 131.54, 131.63, 140.73, 145.70, 147.90, 148.09, 150.12, 161.49, 162.19, 163.92, 164.65.

Example 40: 2-methyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Pale yellow solid, MS [M-H]⁺ = 358.4.

Example 41 : l-((3-fluorophenyl)sulfonyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. Pale yellow solid, MS [M-H]⁺ = 376.3.

Example 42 : 2-ethyl- 1 -((3 -methylphenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine. Pale yellow solid, MS [M-H]⁺ = 385.2.

Example 43 : l-((4-aminophenyl)sulfonyl)-2-ethyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. Pale yellow solid, MS [M-H]⁺ = 387.2.

Example 44: 2-ethyl-l-((3-fluorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. Pale yellow solid, MS [M-H]⁺ = 406.1.

Example 45: 2-isopropyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine. Pale yellow solid, MS [M-H]⁺ = 402.2.

Example 46: 3-((3-chlorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- c]pyridine. White solid, MS [M-H]⁺ = 420.2; 1H NMR (500 MHz, OMSO-d₆) δ ppm 1.28 (d, J=6.87 Hz, 6 H) 3.15 - 3.20 (m, 5 H) 3.75 (quin, J=6.59 Hz, 1 H) 4.12 - 4.18 (m, 4 H) 7.33 (d, J=5.73 Hz, 1 H) 7.67 (t, J=8.02 Hz, 1 H) 7.85 - 7.89 (m, 1 H) 7.96 (dt, J=8.02, 1.43 Hz, 1 H) 8.00 (d, J=5.73 Hz, 1 H) 8.10 (t, J=2.00 Hz, 1 H). ¹³C NMR (125 MHz, OMSO-d₆) δ ppm 22.66, 28.45, 31.20, 43.15, 43.54, 101.17, 125.83, 132.98, 135.38, 136.29, 139.10, 139.74, 143.40, 150.45, 157.23.

Example 47 : 1 -((3 -fluorophenyl)sulfonyl)-2-i sopropyl-4-(3 -methylpiperazin- 1 -yl)- 1 H- imidazo[4,5-c]pyridine. White solid, MS [M-H]⁺ = 385.3.

Example 48 : 2-isopropyl- 1 -((3 -methoxyphenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine. White solid, MS [M-H]⁺ = 416.2.

Example 49: 3-((4-fluorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5- c]pyridine. White solid, MS [M-H]⁺ = 404.2.

Example 50: l-((3-chlorophenyl)sulfonyl)-2-cyclopentyl-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. White solid, MS [M-H]⁺ = 446.5.

Example 51 : 2-butyl- 1 -((3 -chlorophenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5- c]pyridine. White solid, MS [M-H]⁺ = 434.2; 1H NMR (500 MHz, DMS0 ) δ ppm 0.84 - 0.89 (m, 3 H) 1.33 - 1.41 (m, 2 H) 1.65 - 1.75 (m, 2 H) 2.79 (d, J=4.58 Hz, 4 H) 3.06 - 3.11 (m, 2 H) 3.87 - 3.93 (m, 4 H) 7.17 - 7.20 (m, 1 H) 7.63 - 7.68 (m, 1 H) 7.85 (dt, J=8.02, 1.15 Hz, 1 H) 7.93 (d, J=5.73 Hz, 1 H) 7.96 - 7.99 (m, 1 H) 8.08 (t, J=2.00 Hz, 1 H). ¹³C NMR (125 MHz, DMS0 ) δ ppm 14.18, 22.18, 29.08, 29.70, 45.62, 46.95, 124.68, 125.52, 126.33, 126.90, 132.89, 135.31, 136.17, 139.1, 139.69, 143.40, 151.29.

Example 52: 2-butyl-l-((4-fluorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. White solid, MS [M-H]⁺ = 418.3.

Example 53 : 2-butyl-l-((4-methoxyphenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine. White solid, MS [M-H]⁺ = 430.3.

Example 54: l-((3-chlorophenyl)sulfonyl)-2-(4-methoxyphenyl)-4-(piperazin-l-yl)-lH- imidazo[4,5-c]pyridine. White solid, MS [M-H]⁺ = 484.3.

Test Examples

Test Example 1 A - in vitro evaluation

Radioligand binding assays were employed for determining the affinity and the selectivity profile of the synthesized compounds for cloned serotonin: 5-HT_IA, 5-HT₂A, 5-HT₆, 5-HT₇ and dopamine D_2L receptors, all stably expressed in HEK293 cells except 5-HT₂A which was stably expressed in CHO-K1 cells. This was accomplished by displacement of respective radioligands from cloned human receptors: [³H]-8-OH-DPAT for 5-HTlAR, [³H]-ketanserin for 5-HT_2AR, [³H]-LSD for 5-HT₆R, [³H]-5-CT for 5-HT₇R and [³H]-raclopride for D₂R Cell culture and preparation of cell membranes

HEK293 cells with stable expression of human serotonin 5-HT_IAR, 5-HT₆, 5-HT_7bR or dopamine D_2LR (all prepared with the use of Lipofectamine 2000) were maintained at 37°C in a humidified atmosphere with 5% C0₂ and were grown in Dulbeco's Modifier Eagle Medium containing 10% dialysed foetal bovine serum and 500 mg/ml G418 sulphate. For membranes preparations, cells were subcultured in 10 cm diameter dishes, grown to 90% confluence, washed twice with prewarmed to 37°C phosphate buffered saline (PBS) and were pelleted by centrifugation (200 g) in PBS containing 0.1 mM EDTA and 1 mM dithiothreitol. Prior to membrane preparations pellets were stored at -80°C.

CHO-K1 cells with stable expression of human serotonin 5-HT₂AR were purchased from PerkinElmer BioSignal Inc and were maintained according to manufacturer's protocol.

Radioligand binding assays

Cell pellets were thawed and homogenized in 20 volumes of assay buffer using an Ultra Turrax tissue homogenizer and centrifuged twice at 35 000 g for 20 min at 4°C, with incubation for 15 min at 37°C in between. The composition of the assay buffers was as follows: for 5-HTi_AR: 50 mM Tris-HCl, 0.1 mM EDTA, 4 mM MgCl₂, 10 mM pargyline and 0.1% ascorbate; for 5-HT_2AR: 50 mM Tris-HCl, 4 mM MgCl₂ and 0.1% ascorbate; for 5- HT₆R: 50 mM Tris-HCl, 0.5 mM EDTA and 4 mM MgCl₂, for 5-HT_7bR: 50 mM Tris-HCl, 4 mM MgCl₂, 10 mM pargyline and 0.1% ascorbate; for dopamine D_2LR: 50 mM Tris-HCl, 1 mM EDTA, 4 mM MgCl₂, 120 mM NaCl, 5 mM KC1, 1.5 mM CaCl₂ and 0.1% ascorbate. All assays were incubated in a total volume of 200 ml in 96-well microtitre plates for 1 h at 37°C, except for 5-HT_IAR and 5-HT₂AR which were incubated for 1 h at room temperature and at 27°C respectively. The process of equilibration is terminated by rapid filtration through Unifilter plates with a 96-well cell harvester and radioactivity retained on the filters was quantified on a Microbeta plate reader.

For displacement studies the assay samples contained as radioligands: 1.5 nM [³H]- 8-OH-DPAT (135.2 Ci/mmol) for 5-HTi_AR; 2nM [³H]-Ketanserin (53.4 Ci/mmol) for 5- HT_2AR; 2 nM [³H]-LSD (83.6 Ci/mmol) for 5-HT₆R; 0.6 nM [³H]-5-CT (39.2 Ci/mmol) for 5-HT₇R or 2.5 nM [³H]-Raclopride (76.0 Ci/mmol).

Non-specific binding is defined withlO μΜ of 5-HT in 5-HT_IAR and 5-HT₇R binding experiments, whereas 20 μΜ of mianserin, 10 μΜ of methiothepine or 1 μΜ of (+)butaclamol were used in 5-HT₂AR, 5-HT₆R and D_2L assays, respectively.

Each compound was tested in triplicate at 7-8 concentrations (10^~n-10^~4 M). The inhibition constants (Ki) were calculated from the Cheng-Prusoff equation: (Cheng et al., 1973).

„ IC₅₀

^Ki Ί

Results were expressed as means of at least three separate experiments.

Membrane preparation and general assay procedures for cloned receptors were adjusted to 96-microwell format based on described protocols (Perkin Elmer).

Membrane preparation and general assay procedures for cloned receptors were adjusted to 96-microwell format based on described protocols (Bojarski et al., 1993; Paluchowska et al., 2007; Zajdel et al., 2012a; Zajdel et al., 2012b). Table 1 A. The binding data of the library members for 5-HT₆ receptors.

Table IB . The binding data of the library members for 5-HTIA, 5-HT₂A, 5-HT₆, 5-HT₇ and D₂ receptors.

Test Example 2 - in vitro functional activity ago-/antago-nism) on human 5-HT₆ receptors Test and reference compounds were dissolved in dimethyl sulfoxide (DMSO) at a concentration of 1 mM. Serial dilutions were prepared in 96-well microplate in assay buffer and 8 to 10 concentrations were tested.

A cellular aequorin-based functional assay was performed with recombinant CHO-Kl cells expressing mitochondrially targeted aequorin, human GPCR and the promiscuous G protein al6 for 5-HT6. Assay was executed according to previously described protocol [1]. After thawing, cells were transferred to assay buffer (DMEM/HAM's F12 with 0.1% protease free BSA) and centrifuged. The cell pellet was resuspended in assay buffer and coelenterazine h was added at final concentrations of 5 μΜ. The cells suspension was incubated at 16 °C, protected from light with constant agitation for 16 h and then diluted with assay buffer to the concentration of 100,000 cells/ml. After 1 h of incubation, 50 μΐ of the cells suspension was dispensed using automatic injectors built into the radiometric and luminescence plate counter MicroBeta2 LumiJET (PerkinElmer, USA) into white opaque 96-well microplates preloaded with test compounds. Immediate light emission generated following calcium mobilization was recorded for 60 s. In antagonist mode, after 30 min of incubation the reference agonist was added to the above assay mix and light emission was recorded again. Final concentration of the reference agonist was equal to EC80 (40 nM serotonin).

Table 2A. The agonist and antagonist effect of the selected library members for 5-HT₆ receptors.

Antagonist response

Compound _{1 0E}-06 lOE^"07

3 80 29

5 96 82

6 45 0

9 99 99

10 97 93

15 48 0

16 98 87

17 98 64

28 48 100

29 98 97

35 79 19

37 81 0

38 86 28

39 89 22

41 98 80

48 90 76

49 93 80

51 93 75

52 97 87 Table 2B. Functional data for selected compounds for 5-HT₆ receptors.

Compound Ki [nM] K_h [nM]

SB-742457 2 0.1

5 26 2.3

11 12 0.6

16 20 1.0

46 13 2.2

Cited literature

1. Berge, S.M.; Bighley, L.D.; Monkhause, D.C. J. Pharm. Sci. 1977, 66, 1-19.

2. Benhamu, B.; Martin-Fontecha, M.; Vazquez- Villa, H.; Pardko, L.; Lopez-Rodriguez, M.

J. Med. Chem. 2014, 57, 7160-7181.

3. Bojarski, A.J.; Cegla, M.T.; Charakchieva-Minol, S.; Mokrosz, M.J.; Mackowiak, M.;

Misztal, S.; Mokrosz, J.L. Pharmazie 1993, 48, 289-294.

4. Cheng, Y.; Prusoff, W.H. Biochem Pharmacol. 1973, 22, 3099.

5. Hannon, J.; Hoyer, D. Behav. Brain Res. 2008, 195, 198-213.

6. Holenz, J.; Pauwels, P. J.; Diaz, J. L.; Merce, R.; Codony, X.; Buschmann, H. Drug Dwcov. Today 2006, 77, 283-299.

7. Ivachtchenko, A.V.; Ivanenkov, Y.A.; Skorenko, A.V. Expert Opin. Ther Pat. 2012, 22, 1123-1168.

8. Mitchell, E. S.; Neumaier, J. F. 5-HT₆ receptors: A novel target for cognitive enhancement. Pharmacol. Ther. 2005, 108, 320-333.

9. Paluchowska, M.H.; Bugno, R.; Tatarczyhska, E.; Nikiforuk, A.; Lenda, T.; Chojnacka- Wojcik, E. Bioorg. Med. Chem. 2007, 15, 7116.

10. Upton, N.; Chuang, T.T.; Hunter, A.J.; Virley, D.J. Neurotherapeutics 2008, 5, 458.

11. Zajdel P.; Kurczab R; Grychowska K.; Satala G.; Pawlowski M.; Bojarski A. J., Eur. J.

Med. Chem., 2012a, 56, 348-60.

12. Zajdel, P.; Marciniec, K.; Maslankiewicz, A.; Satala, G.; Duszynska, B.; Bojarski, A. J.;

Partyka, A.;

M.; Wrobel, D.; Wesolowska, A.; Pawlowski, M.

Bioorg. Med. Chem., 2012b, 20, 1545-1556.

13. Kolaczkowski M.; Marcinkowska M.; Bucki A.; Pawlowski M.; Mitka K.; Jaskowska J.;

Kowalski P.; Kazek G.; Siwek A.; Wasik A.; Wesolowska A.; Mierzejewski P.; Bienkowski P. J Med Chem., 2014, 12, 4543-4557.

Claims

Claims

1. A compound of formula (I), or a tautomer, stereoisomer, enantiomer, N-oxide, a pharmaceutically acceptable salt, hydrate or solvate thereof:

wherein:

- A¹ and A² are different and selected from nitrogen or carbon atom;

- Ri represents H or C1-C3 alkyl, preferably Ri represents H or methyl;

- R₂ represents hydrogen, an unsubstituted C1-C5 alkyl, an C1-C5 alkyl substituted with one or more halogen atoms, hydroxyl, a branched C1-C5 alkyl, a 5 to 6 membered aryl or a 5 to 6 membered heteroaryl, optionally substituted with one or more substituents selected from C1-C2 alkyl, one or more halogen atoms, C1-C2 alkoxy, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide, preferably R₂ represents hydrogen, an unsubstituted C1-C5 alkyl, a 6 membered aryl, a 6 membered aryl substituted with halogen atom or C1-C2 alkoxy or 5 membered heteroaryl;

- T represents -CH₂- , -S0₂- or substituted C1-C2 alkyl group;

- R₃ represents a 5 to 6 membered unsubstituted aryl, a 8 to 10 membered biaryl, a 5 to 6 membered heteroaryl, a 8 to 10 membered heteroaryl, optionally substituted with one or more substituents selected from C1-C3 alkyl, an C1-C3 alkyl substituted with one or more halogen atoms, C1-C3 alkoxy, C2-C4 alkenyl, halogen, nitro, hydroxyl, cyano, amino, alkylamino, carboxamide, preferably R₃ represents a 6 membered aryl or heteroaryl, a 6 membered aryl substituted with one or more halogen atoms, C1-C2 alkoxy or an C1-C3 alkyl substituted with one or more halogen atoms.

2. A Compound according to claim 1, wherein: A¹, A², Ri, R₂ and R₃ are as defined in claim 1 and T represents -CH₂-, -CH₂-CH₂-or -CH(CH₃)-.

3. A Compound according to claim 1, wherein: Ri, R₂ and R₃ are as defined in claim 1, A¹ is carbon, A² is nitrogen and T represents -S0₂- .

4. A compound according to claim 1, which is:

3-benzyl-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(2-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-chlorobenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

1- (3-chlorobenzyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- methyl-3-(2-methylbenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3- (2-Methoxybenzyl)-2-methyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

1 -(4-fluorobenzyl)-2-methyl-4-(piperazin- 1 -yl)- lH-imidazo[4, 5-c]pyridine,

3-(2-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-chlorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(2-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

2- ethyl-3-(3-fluorobenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3- (2,5-difluorobenzyl)-2-ethyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

2- ethyl-3-(3-fluorophenethyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

1- (2-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

3- (3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-fluorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

2- Isopropyl-3-(3-methoxybenzyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3- (4-chlorobenzyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-fluorobenzyl)-2-isopropyl-7-(3-methylpiperazin-l-yl)-3H-imidazo[4,5-b]pyridine, (S)-3-(3-fluorobenzyl)-2-isopropyl-7-(3-methylpiperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

1- (4-fluorobenzyl)-2-isopropyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- isopropyl-7-(piperazin-l-yl)-3-(pyridin-4-ylmethyl)-3H-imidazo[4,5-b]pyridine,

3- (l-(3-fluorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine, (S)-3-(l-(3-fluorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine, (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine, (R)-3-(l-(3-chlorophenyl)ethyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine, 3-(2-chlorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-methylbenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(4-fluorobenzyl)-2-(pentan-3-yl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(2-chlorobenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-methylbenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine, 3-(3-methoxybenzyl)-2-neopentyl-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-chlorobenzyl)-7-(piperazin-l-yl)-2-(thiophen-2-yl)-3H-imidazo[4,5-b]pyridine,

7-(piperazin-l-yl)-2-(thiophen-2-yl)-3-(3-(trifluoromethyl)benzyl)-3H-imidazo[4,5- b] pyridine,

3-benzyl-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(2-fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-chlorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

3-(3-fluorobenzyl)-2-(4-fluorophenyl)-7-(piperazin-l-yl)-3H-imidazo[4,5-b]pyridine,

2-methyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

1- ((3-fluorophenyl)sulfonyl)-2-methyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- ethyl-l-((3-methylphenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

1- ((4-aminophenyl)sulfonyl)-2-ethyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- ethyl-l-((3-fluorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- isopropyl-l-(phenylsulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

3- ((3-chlorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-c]pyridine,

1- ((3-fluorophenyl)sulfonyl)-2-isopropyl-4-(3-methylpiperazin-l-yl)-lH-imidazo[4,5- c] pyridine,

2- isopropyl-l-((3-methoxyphenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

3- ((4-fluorophenyl)sulfonyl)-2-isopropyl-7-(piperazin-l-yl)-3H-imidazo[4,5-c]pyridine,

1- ((3-chlorophenyl)sulfonyl)-2-cyclopentyl-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2- butyl-l-((3-chlorophenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine,

2-butyl- 1 -((4-fluorophenyl)sulfonyl)-4-(piperazin- 1 -yl)- lH-imidazo[4, 5-c]pyridine,

2-butyl-l-((4-methoxyphenyl)sulfonyl)-4-(piperazin-l-yl)-lH-imidazo[4,5-c]pyridine or l-((3-chlorophenyl)sulfonyl)-2-(4-methoxyphenyl)-4-(piperazin-l-yl)-lH-imidazo[4,5- c]pyridine.

5. A compound as defined in any of claims 1 to 4 for its use in the manufacture of a medicament.

6. A compound as defined in any of claims 1 to 4 for its use in the prevention or treatment of diseases, disorders or conditions resulting from disturbance of 5-HT₆ transmission.

7. A compound as defined in any of claims 1 to 4 for its use in the prevention or treatment of schizophrenia, anxiety, depression, maniac depression, epilepsy, obsessive compulsive disorders, mood disorders, migraine, Alzheimer's disease, age related cognitive decline, mild cognitive impairment, sleep disorders, eating disorders, anorexia, bulimia, panic attacks, attention deficit hyperactivity disorder, attention deficit disorder, Parkinson's disease, Huntington's disease, withdrawal from abuse of ***e, ethanol, nicotine or benzodiazepines, pain, neuropathic pain, obesity and type-2 diabetes, functional bowel disorder, Irritable Bowel Syndrome.