DESCRIPTION TECHNICAL FIELD OF THE INVENTION

The invention relates to a new class of compounds able to bind with high affinity and selectivity the 5-HT7 receptor. The invention also relates to the utilization of such compounds as medicaments useful in the treatment and prevention of 5-HT7 receptor relating disorders of the central nervous system. The invention also relates to the isotopically labeled compounds for use in vivo diagnosis or imaging of a 5-HT7 condition. BACKGROUND OF THE INVENTION

Serotonin (5-hydroxytryptamine, 5-HT) elicits a multitude of physiological effects through the interaction with at least fourteen receptors that have been grouped on the basis of molecular, pharmacological, and functional criteria into seven discrete families (5- HT1-7) [1] . The 5-HT7 receptor was identified starting from 1993 by the application of targeted molecular biology techniques. It has been described in various species and remains the last 5-HT receptor to be discovered. The 5-HT7 receptor has been localized in discrete areas of the brain and in the periphery. Within the central nervous system this receptor has been detected in high levels in the thalamus, hippocampus, and hypothalamus (especially within the suprachiasmatic nucleus, SCN) [2] . Much information is available on the pathophysiological role of 5-HT7 receptor in the central nervous system. The availability of the selective 5-HT7 antagonist SB-269970 and of 5-HT7-knockout mice has allowed relevant insight into the role of 5-HT7 receptors in depression. As an example, pharmacological blockade of 5-HT7 receptor or inactivation of the receptor gene leads to an antidepressant-like behavioral profile in rodent models of depression (forced swim test and tail suspension test) [3]. Recently, it has been suggested that the atypical antipsychotic drug amisulpride exerts its antidepressant action through blockade of 5-HT7 receptors [4] . It should also be noted that the atypical antipsychotic aripiprazole has high affinity for the 5- HT7 receptor [5,6] and it is successfully used to augment the effect of traditional antidepressants [7]. These findings further support the potential of 5-HT7 receptor antagonists to yield a novel class of antidepressant drugs. The recent availability of selective agonists such as AS-19, E-55888, and LP-211 is opening up new scenarios on the therapeutic actions of 5-HT7 receptor activation. It has been demonstrated that behavioral antinoception can be achieved by systemic administration of AS-19 or E- 55888 [8] . Also, AS-19 has served to demonstrate the involvement of 5-HT7 receptor in memory formation [9] . In addition, it has been found that the stimulation of cultured striatal neurons with the mixed 5-HT1A/7 agonist, 8-OH-DPAT, or with the selective 5-HT7 agonist, LP-211, induced a marked neurite outgrowth. This effect was specifically triggered by 5-HT7 receptor activation, because it was blocked by application of SB-269970 [10, 11] . These data supported the crucial role of this receptor in the modulation of neuronal morphology, as also observed in mouse hippocampal neurons following 5- HT7 receptor activation [12]. Finally, selective activation of 5-HT7 receptors may represent a novel strategy in the therapy of Fragile X syndrome [13] .

The international application WO2008146064A1 disclosed some benzofuran compounds that bind 5-hydroxy triptamine- 7 receptor for use in the treatment or prevention of disorders of central nervous system and/or cardiovascular disorders .

The compounds reported in the state of the art with high affinity for the 5-HT7 receptor suffer from the lack of selectivity over a range of 5-HT receptors [14] . Also, the most potent 5-HT7 ligands proposed to date are not sufficiently metabolically stable. This precludes the use of such compounds as in vivo tools for studying the function of 5-HT7 receptor and as drugs. Moreover, to date no positron emission tomography tracer is available to visualize 5-HT7 receptor in either central nervous system or periphery.

The co-pending international application

PCT/EP2011/058419, filed by the present inventors, describes some 1-arylpiperazinic ligands of 5-HT7 receptor and used thereof.

SUMMARY OF THE INVENTION

The present invention relates to new compounds that present high affinity and selectivity for 5-HT7 receptors as well as good pharmacokinetic properties. Several 5-HT7 ligands reported in literature have not been characterized regarding their metabolic liability or, when these data are available, they demonstrated a very short half-life time that limit their in vivo use. As example, plasma and brain concentration of LP-44 [12] became undetectable after 20 minutes following i.p injection. The compounds of the present invention exhibit chemical features (i.e.: electron-withdrawing groups) that make them less metabolically liable. Moreover, the compounds of the present invention possess optimal lipophilicity (2< logP > 3.5) for both in vivo use and for the development of a brain PET tracer. It is well- known that high lipophilicity reflects in high metabolic liability when administered in vivo and in low image resolution in PET imaging.

Finally, the compounds described in the present invention present structural features that allow easy radiolabelling with positron emitter radioisotopes.

Hence, object of the present invention is a family of compounds having the general formula as indicated in claim 1. A second object of the invention are compounds selected from the above-indicated families isotopically radiolabeled .

A third object of the invention are compounds selected from the above-indicated families for use as medicaments, advantageously for use in the treatment of any condition susceptible of being improved or prevented by selective occupation of the 5-HT7 receptor.

A fourth object of the invention are compounds isotopically radiolabeled selected from the above- indicated families for use in vivo diagnosis or imaging of a 5-HT7 condition.

A further object of the invention are a pharmaceutical composition comprising the compounds of the invention and a pharmacologically acceptable excipient.

Other objects will be made evident in the light of the following detailed description.

The results reported in the experimental part demonstrate that compounds of the invention are able to bind with high affinity and selectivity the 5-HT7 receptor.

DETAILED DESCRIPTION OF THE INVENTION.

Compounds of the Invention

The invention relates to a family of novel compounds having the following general formula I:

(I) wherein : A, B, D, E are independently CH or N with at most two of A, B, D, E being N;

Ri is selected from the group consisting of hydrogen, halogen, (C1-C2) alkyl, optionally further substituted with 1 to 5 fluorine substituents , (C1-C2 ) alkoxy, optionally further substituted with 1 to 5 fluorine substituents, cyano, (C1-C2) alkyl-S (0) 2-, X and Y are two linking chains, which may either independently be a (C1-C2 ) alkylen group or be absent, provided that at least one of X and Y is present; provided that when either X or Y is absent, R ₂ is hydrogen or (C1-C2 ) alkyl ;

W is selected from: -C (0) - (CH2 ) n- , -S02- (CH2) n-, -C (0) - (CH2) 2-0- (CH2) 2-, wherein n is from 2 to 5;

Z is selected from:

K, J, L, M are independently CH or N with at most one of A, B, D, E being N;

Q is substituted or unsubstituted alkyl or alkoxy; substituted or unsubstituted cycloalkyl; substituted or unsubstituted aryl; substituted or unsubstituted heterocyclyl . when Z is the compound is selected from the group consisting of:

3- [2- [4 - (2-Biphenyl) piperazin-l-yl ] ethoxy] -N- (4- cyanophenylmethyl ) propanamide

3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4- trifluoromethylphenylmethyl ) propanamide

3- [2- [4 - (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4- methanesuIfonyloxyphenylmethyl ) propanamide

3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4- pyridylmethyl ) propanamide

3- [2- [4 - (2-Biphenyl) piperazin-l-yl] ethoxy] -1-isoindolin- 2-yl-propan-l-one

1- (3, 4-dihydro-lH-isoquinolin-2-yl) -3- [2- [4- (2- biphenyl) piperazin-l-yl] ethoxy] propan-l-one

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxyphenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (2- methylphenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (2- methoxyphenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (4-Methoxyphenylmethyl) -3- [2- [4- [2- (4- fluorophenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (4- fluorophenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Bromo-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2-biphenyl] -1- piperazinehexanamide N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4- methoxyphenyl ) phenyl] -1-piperazinehexanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4-pyridyl) pyridyl] - 1-piperazinehexanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [3- (4-pyridyl) pyridyl] -

1-piperazinehexanamide

2- [6- [4- [2- (4-Methoxyphenyl) phenyl) -1-piperazinyl ] -1- oxohexyl] -1,2,3, 4-tetrahydroisoquinoline

2- [6- [4- [3- (4-pyridyl) pyridyl] -1-piperazinyl] -1- oxohexyl] isoindoline

N-Methyl-N- (2-pyridyl) -4- [2- (2-methylphenyl) phenyl] - 1- piperazinehexanamide

N-Methyl-N- (pyridin-3-ylmethyl ) -3- [2- [4- [2- (4- fluorophenyl ) phenyl] piperazin-l-yl ] ethoxy] propanamide

N-Methyl-6- [4- [2- ( 4 -methoxyphenyl ) phenyl ] -N- (2-pyridyl) - 1-piperazinehexanamide

N-Benzyl-3- [2- [4- [2-biphenyl] piperazin-l-yl] ethoxy] -N- methyl-propanamide

N-Methyl-N- (2-pyridyl) -3- [2- [4- [2- (4- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide

According to one embodiment of the invention Q is aromatic substituted with halogen, (Cl-C2)alkyl optionally further substitued with 1 to 5 fluoro substituents , (C1-C2 ) alkoxy optionally further substitued with 1 to 5 fluoro substituents, cyano .

According to another embodiment of the invention ]¾ is hydrogen and W is -C (0) - (CH2 ) n- wherein n is 2, 3, 4 or 5. According to one embodiment of the invention ]¾ is hydrogen and W is -C (0) - (CH2) 2-0- (CH2) 2- .

According to another embodiment of the invention R ₂ is hydrogen, W is -C (0) - (CH2 ) n- wherein n is 2, 3, 4 or 5. According to another embodiment of the invention Z is:

According to another embodiment of the invention Z is:

According to another embodiment

Specific examples of compounds of the invention identified with their IUPAC definition and their chemical formula are: 3- [2 - [4 - ( 2 -Biphenyl ) piperazin- 1-yl] ethoxy] -N- (4- cyanophenylmethyl ) propanamide

3- [2- [4- (2 -Biphenyl) piperazin- 1 -yl ] ethoxy] -N- (4- trifluoromethylphenylmethyl ) propanamide

3- [2- [4 - (2 -Biphenyl) piperazin- 1 -yl ] ethoxy] -N- (4- methanesuIfonyloxyphenylmethyl ) propanamide

3- [2- [4- (2 -Biphenyl) piperazin- 1 -yl ] ethoxy] -N- (4- pyridylmethyl ) propanamide

3- [2- [4 - (2 -Biphenyl) piperazin- 1 -yl ] ethoxy] -1-isoindolin- 2 -yl-propan-1 -one 1- (3, 4-dihydro-lH-isoquinolin-2-yl) -3- [2- [4- (2- biphenyl) piperazin- 1 -yl ] ethoxy] propan-1 -one

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxyphenyl ) phenyl] piperazin-l-yl ] ethoxy] propanamide N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (2- methylphenyl ) phenyl] piperazin-l-yl ] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (2- methoxyphenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (4-Methoxyphenylmethyl) -3- [2- [4- [2- (4- fluorophenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (4- fluorophenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N- (2-Bromo-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2-biphenyl] -1- piperazinehexanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4- methoxyphenyl ) phenyl] -1-piperazinehexanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4-pyridyl) pyridyl] 1-piperazinehexanamide

N- (2-Fluoro-pyridin-5-ylmethyl) -4- [3- (4-pyridyl) pyridyl]

1-piperazinehexanamide

2- [6- [4- [2- (4 -Methoxyphenyl) phenyl) -1-piperazinyl ] -1- oxohexyl] -1,2,3, 4-tetrahydroisoquinoline

2- [6- [4- [3- (4-pyridyl) pyridyl] -1-piperazinyl] -1- oxohexyl] isoindoline

N-Methyl-N- (2-pyridyl) -4- [2- (2-methylphenyl) phenyl] - 1- piperazinehexanamide

N-Methyl-N- (pyridin-3-ylmethyl ) -3- [2- [4- [2- (4- fluorophenyl ) phenyl] piperazin-l-yl] ethoxy] propanamide

N-Methyl-6- [4- [2- ( 4 -methoxyphenyl ) phenyl ] -N- (2-pyridyl) - 1-piperazinehexanamide

N-Benzyl-3- [2- [4- [2-biphenyl] piperazin-l-yl] ethoxy] -N- methyl-propanamide

N-Methyl-N- (2-pyridyl) -3- [2- [4- [2- (4- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- (2-biphenyl) -1- piperidyl ] ethoxy] propanamide

N- (4-Pyridinylmethyl) -3- [2- [4- (2-biphenyl) -1- piperidyl ] ethoxy] propanamide

4- (2-Biphenyl) -N- (4-pyridinylmethyl) -1- piperidinehexanamide

4- (2-Biphenyl) -N- (2-fluoro-pyridin-5-ylmethyl) -1- piperidinehexanamide

N-Methyl-N- ( 2 -pyridinyl ) -4- [2- (2-biphenyl) ] -1- piperidinehexanamide

N-Methyl-N- (pyridin-3-ylmethyl ) -3- [2- [4- (2- biphenyl) piperid-l-yl ] ethoxy] -propanamide

4- (2-Biphenyl) -N- (4-pyridinylmethyl) -1- piperidinehexanamide

N- [ (4-Cyanophenyl) methyl] -3- [ [1- (2-biphenyl) -4- piperidyl ] methylamino ] propanamide

N- (2-Fluoropyridin-5-ylmethyl) -3- [1- (2-biphenyl) -4- piperidyl ] methylamino ] propanamide

N- [ (4-Trifluoromethylphenyl) methyl] -3- [1- (2-biphenyl) -4- piperidyl ] methylamino ] propanamide l-Isoindolin-2-yl-3- [ [1- (2-biphenyl) -4- piperidyl] methylamino] propan-l-one

Compounds of the invention isotopically labeled

The present invention also encompasses isotopically radiolabeled compounds which are identical to the compounds of formula I or intermediates thereof but for the fact that one or more atoms are replaced by an atom having atomic mass or mass number different from the atomic mass or mass number usually found in nature. Example of isotopes that can be incorporated into the intermediates or compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen and fluorine, such as ³ H, ^X1 C, ¹⁴ C, ¹³ N, ¹⁵ 0, ¹⁸ F, respectively.

Method for preparing the compounds of the invention

The compounds of formula I of the present invention can be prepared according the procedures of the following Schemes. Suitable reaction conditions for the steps of these schemes are well known in the art and appropriate substitutions of solvents and co-reagents are within the skill of the art. The synthetic intermediates may be isolated and/or purified by various well known techniques . Reaction Scheme I illustrates the methods employed in the synthesis of the compounds of formula I when W is -C (0) - (CH2 ) 2-0- (CH2 ) 2- . All substituent are as defined above unless indicated otherwise.

Scheme I

A: 2-bromoethanol ; B: i) NaH; ii)t-butyl acrylate; C: 3N HC1; D) i ) 1 , 1 ' -carbonyldiimidazole ; ii) amine In Scheme 1 the appropriate amine 1 was reacted with 2- bromoethanol to give alcohol 2, that was condensed with t-butyl acrilate under Michael addition condition to give ester 3. The latter was hydrolized to afford the acid 4 that was condensed with the appropriate amine to give compound 5.

Reaction Scheme II illustrates the synthesis of the compounds of formula I when W is -C (0) - (CH2 ) 5- . All substituent are as defined above unless indicated otherwise .

Scheme II

A: 6-bromohexanoylchloride, NaOH; B: amine

In Scheme II, an appropriately substituted amine (5 reacted with the appropriate bromoalkanoylchloride to give the amide 1_. The reaction with the appropriate substitued amine afforded compound 8.

General procedure for radiosynthesis

The incorporation of radioactive fluorine atom into the compounds of formula (I) may be performed using techniques known in the art, for example by reaction of a suitable precursor, bearing a leaving groups, such as mesylate, triflate, nitro, tosylate, bromine, with a nucleophilic radioactive fluorinating reagent, such as K [ ¹⁸ F] /Kriptofix®222 or tetralkyl ammonium salts incorporating radioactive fluoride. The reaction is carried out in an inert solvent such as, dimethylformamide, stirring the reaction mixture at a suitable temperature, typically at 100 °C, using conventionally heating or under microwave irradiation, for the required time to achieve completion of the reaction. The incorporation of radioactive 11-Carbon atom into the compounds of formula (I) may be performed, for example by reaction of a suitable precursors bearing a phenolic hydroxyl group with radioactive methylating reagent, such as [ ^C l Cfm , [^CJCHSOTf. The reaction is performed in an inert solvent such as dimethylformamide, in the presence of a strong base, such as NaOH, stirring the reaction mixture at a suitable temperature until complete achievement of the reaction. Therapeutic applications

A further object of the present invention is a compound selected from the above-indicated families for use as medicament .

The compounds of the invention able to inhibit with high affinity and selectivity the 5-HT7 receptor activity find therapeutic applications in the treatment of any condition susceptible of being improved or prevented by selective occupation of the 5-HT7 receptor.

Disorders of the central nervous system linked to the 5-

HT7 receptor activity comprise migraine, anxiety, persistent pain, inflammatory pain, neuropathic pain, depression, anxiety. Compounds of the invention isotopically labeled for use in vivo diagnosis or imaging.

Isotopically labeled compounds of the present invention are useful in vivo diagnosis or imaging of a 5-HT7 condition. For example compounds labeled with positron emitting isotopes such as ¹¹ C, ¹³ N, ¹⁵ 0, ¹⁸ F are useful for Positron Emission Tomography (PET) analysis.

Radiotracers of the present invention are useful for assessing 5-HT7 receptors using PET, particularly in patient populations and preferably in subjects having or being diagnosed disorders as described herein. Further, radiotracers of the present invention are useful in drug development and drug discovery, for example, in neuroscience to assess interaction of drugs with 5-HT7 receptors or substrate occupancy.

Pharmaceutical compositions

A further object of the invention is a pharmaceutical composition comprising the compounds selected from the above-indicated families and a pharmacologically acceptable excipient and/or carrier. Preferably these compositions are in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, auto-injector devices or suppositories; for oral, parenteral, intranasal, sublingual or rectal administration, or for administration by inhalation or insufflation. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of the active ingredient of the present invention. Typical unit dosage forms contain from 1 to 100 mg, for example 1, 2, 5, 10, 25, 50 or 100 mg, of the active ingredient. The tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, acetyl alcohol and cellulose acetate.

The liquid forms in which the novel compositions of the present invention may be incorporated for administration orally or by injection include aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or suspending agents for aqueous suspensions include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinyl ^¬ pyrrolidone or gelatin. Thus, based on the above, a variety of pharmaceutically acceptable doses are provided .

Also, it is noted that the term "pharmaceutically acceptable salt(s)" refers to salts derived from treating a compound of formula 1 with an organic or inorganic acid such as, for example, acetic, lactic, citric, cinnamic, tartaric, succinic, fumaric, maleic, malonic, mandelic, malic, oxalic, propionic, hydrochloric, hydrobromic, phosphoric, nitric, sulfuric, glycolic, pyruvic, methanesulfonic, ethanesulfonic, toluenesulfonic, salicylic, benzoic, or similarly The pharmaceutical compositions of the invention are useful in the treatment and prevention of 5-HT7 receptor relating disorders of the central nervous system, in particular for use in the treatment of migraine, anxiety, persistent pain, inflammatory pain, neuropathic pain, depression, anxiety.

Imaging composition

A further object of the invention is a diagnostic imaging composition comprising as imaging agent the compounds selected from the above-indicated families isotopically labeled and a carrier. In accordance with the invention, the radiolabeled compounds according to Formula I, II, III or IV may be administered in a single unit injectable dose. Any of the common carriers known to those with skill in the art, such as sterile saline solution or plasma, can be utilized after radiolabelling for preparing the injectable solution to diagnostically imaging in accordance with the invention. Such techniques include the step of bringing into association the active ingredient and the pharmaceutical carrier (s) or diluent (s) . In general the formulations are prepared by uniformly and intimately bringing into association the active ingredient with the liquid carrier.

The unit dose to be administered for a diagnostic agent has a sufficient radioactivity when they are, for example, 150 MBq. Higher or lower radioactivity may be used according to the circumstances. For diagnostic purposes after intravenous administration, imaging of the organ in vivo can take place in a matter of a few minutes. However, imaging takes place, if desired, in hours or even longer, after injecting into patients. In most instances, a sufficient amount of the administered dose will accumulate in the area to be imaged within about 1 hour to permit the taking of diagnostic images. Any conventional method of imaging for diagnostic purposes can be utilized in accordance with this invention as positron emission tomography (PET) or Single photon emission computed tomography (SPECT) .

The diagnostic imaging compositions of the invention are useful for use in vivo diagnosis or imaging of a 5-HT7 condition.

Method for treatment

It is a further object of the invention a method for treating a disorder of the central nervous system that can be treated by modulating serotonergic neurotransmission in a mammal, comprising administering to a mammal requiring such treatment, preferably a human, an effective amount of a compound of the families described above. In particular for treating the disorder of the central nervous system selected from migraine, anxiety, persistent pain, inflammatory pain, neuropathic pain, depression, anxiety.

In the method of treatment the effective amount administered and frequency of administration of the compounds of the present invention will depend on the particular condition to be treated, the severity of the condition to be treated, age, weight and the overall physical condition of the particular patient as well as on other medicaments the patient is taking, as it is well known to the experts in the field.

The effective amount of the compounds of the invention to be administered daily or per dosage, is within a range of from 0.1 ng to 100 mg per kg body weight, preferably within a range of from 1 ng to 10 mg per kg body weight.

Method for in vivo diagnosis

It is a further object of the invention an in vivo method for diagnosis of a 5-HT7 condition, comprising: administering to a mammal, preferably a human, an effective amount of a isotopically labeled compound of the families described above;

imaging the in vivo 5-HT7 receptor. The imaging technique may be for example Positron emission tomography (PET) or Single positron emission computerized tomography (SPECT) .

In the method of in vivo diagnosis the effective amount administered of the isotopically labelled compounds of the present invention will depend on the particular condition to be diagnosed, the age, weight and the overall physical condition of the particular patient as it is well known to the experts in the field.

The diagnostically effective amount of the labeled or unlabeled compounds of the present invention to be administered before conducting the in vivo diagnosis is within a range from 0.1 ng to 100 mg per kg body weight, preferably within a range of from 1 ng to 10 mg per kg body weight.

EXAMPLES AND BIOLOGICAL EXPERIMENTA ION

The invention is detailed hereinafter via the following examples of preparation and through the following biological testing.

By the methods described above the following intermediates and final compounds have been obtained.

Examples

Example 1. 3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4-cyanophenylmethyl) propanamide .

1A) 2- [4- (2-Biphenyl) piperazin-l-yl] -1-ethanol .

A mixture of 1- (2-biphenyl) piperazine (1.3 g; 5.5 mmol) ,

2-bromoethanol (0.47 mL; 6.6 mmol), K2C03 (0.91 g; 6.6 mmol) and KI (0.33 g; 2.0 mmol) in CH3CN (20 mL) was stirred under reflux overnight. After cooling, the solvent was removed under reduced pressure and the residue was partitioned between AcOEt (20 mL) and H20 (20 mL) . The organic layer was separated and the aqueous phase was extracted twice with AcOEt. The combined organic layers were dried over Na2S04 and evaporated under reduced pressure. The crude residue was chromatographed (CHC13/MeOH, 19:1, as eluent) to afford pure compound in 55% yield. 1H NMR (CDC13) : δ 2.09 (br s, 1H, D20 exchanged), 2.42 (br s, 4H) , 2.51 (t, 2H, J= 5.3 Hz), 2.86 (app t, 4H) , 3.57 (t, 2H, J= 5.3 Hz), 7.02-7.10 (m, 2H) , 7.26-7.32 (m, 3H) , 7.36-7.41 (m, 2H) , 7.61-7.64

(m, 2H) . GC/MS: m/z, 283 (M+l, 7), 282 (M+, 33), 251 (100) , 236 (20) , 180 (41) .

IB) t-Butyl 3- [2- [4- (2-Biphenyl) piperazin-1- yl ] ethoxy] propanoate .

To a cooled suspension of NaH (0.07 g; 3.0 mmol) in anhydrous THF (5 mL) was added, dropwise and under nitrogen, a solution of Example 1A (0.85 g; 3.0 mmol) in the same solvent (10 mL) . The reaction mixture was stirred at room temperature for 8-10 h until alcohol disappeared. Then, a solution of t-butyl acrylate (0.4 mL; 2.71 mmol) in anhydrous THF was added dropwise and the reaction mixture was stirred at room temperature for 20 h. Then, the solvent was removed under reduced pressure and the residue was cautiuosly taken up with cooled H20 and extracted with AcOEt (2 x 30 mL) . The combined organic layers were washed with brine, dried over Na2S04 and evaporated under reduced pressure. The crude residue was chromatographed (CHC13/AcOEt , 1:1, as eluent) to afford pure compound as a wax solid in 38% yield. 1H NMR (CDC13): δ 1.43 (s, 9H) , 2.40 (br s, 4H) , 2.47 (t, 2H, J= 6.4 Hz), 2.54 (t, 2H, J= 5.8 Hz), 2.86 (app t, 4H) , 3.55 (t, 2H, J= 5.8 Hz), 3.65 (t, 2H, J= 6.4 Hz), 7.02-7.09 (m, 2H) , 7.22-7.31 (m, 3H) , 7.35-7.41 (m, 2H) , 7.61-7.64 (m, 2H) . ESI+/MS m/z 410 (MH+) . ESI+/MS/MS m/z 355 (100) .

IC) 3- [2- [4 - (2-Biphenyl) piperazin-l-yl ] ethoxy] propanoic acid .

To a solution of Example IB (1.14 mmol) in dioxane (5 mL) was added aqueous 3N HC1 (5 mL) . The reaction mixture was stirred at room temperature for 48 h, then dioxane was evaporated in vacuo. The acidic solution was neutralized with diluted NH40H and extracted with AcOEt (3 x 20 mL) . The combined organic layers were washed with brine, dried over Na2S04 and evaporated under reduced pressure to yield the desired compound that was used without further purification. 1H NMR (CDC13) : δ 2.47-2.57 (m, 6H) , 2.64 (t, 2H, J= 5.2 Hz), 2.87-2.95 (m, 4H) , 3.06 ( br s, 1H, D20 exchanged), 3.60 (t, 2H, J= 5.2 Hz), 3.69 (app t, 2H) , 7.02-7.10 (m, 2H) , 7.21-7.33 (m, 3H) , 7.35-7.40 (m, 2H) , 7.58-7.60 (m, 2H) . ESI+/MS m/z 355 (MH+) . ESI+/MS/MS m/z 265 (55), 236 (100), 194 (54).

ID) 3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4- cyanophenylmethyl ) propanamide .

A mixture of Example 1C (0.12 g; 0.32 mmol) and 1,1'- carbonyldiimidazole (0.06 g; 0.38 mmol) in 10 mL of anhydrous THF was stirred for 8 h. A solution of 4- cyanobenzylamine (0.04 g; 0.32 mmol) in anhydrous THF (10 mL) was added, then the mixture was stirred until the acid disappeared (TLC) . The reaction mixture was partitioned between AcOEt (20 mL) and H20 (20 mL) . The separated organic layer was washed with a saturated aqueous solution of Na2C03 (20 mL) , dried (Na2S04) and concentrated in vacuo. The crude residue was chromatographed (CHC13/MeOH, 19:1, as eluent) to give pure compound as a yellow oil (0.06 g; 43% yield) . 1H NMR (CDC13) : δ 2.34 (br s, 4H) , 2.48-2.54 (m, 4H) , 2.72 (app t, 4H) , 3.55 (t, 2H, J= 5.5 Hz), 3.72 (t, 2H, J= 5.5 Hz), 4.50 (d, 2H, J= 6.3 Hz), 6.87 (d, 1H, J= 8.0 Hz), 7.08 (dt, 1H, J= 0.8 and 6.6 Hz), 7.22-7.31 (m, 4H) , 7.35-7.40 (m, 4H) , 7.56-7.64 (m, 4H) . ESI- /MS m/z 467 (M-H) . ESI- /MS/MS m/z 184 (43), 172 (100).

Example 2. 3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4-trifluoromethylphenylmethyl) propanamide .

The title compound was prepared as described for Example 1 starting from Example 1C and 1- (4- trifluoromethylphenyl ) methylamine (0.13 g; 44% yield). 1H NMR (CDC13) : δ 2.33 (br s, 4H) , 2.47-2.54 (m, 4H) , 2.73 (app t, 4H) , 3.56 (t, 2H, J= 5.5 Hz), 3.71 (t, 2H, J= 5.8 Hz), 4.50 (d, 2H, J= 6.1 Hz), 6.88 (d, 1H, J= 7.4 Hz), 7.07 (dt, 1H, J= 1.1 and 6.3 Hz), 7.22-7.33 (m, 4H) , 7.37-7.41 (m, 4H) , 7.54-7.61 (m, 3H) . ESI+/MS m/z 512 (MH+) . ESI+/MS/MS m/z 283 (100), 265 (38), 236 (33).

Example 3. 3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -N- (4-pyridylmethyl) propanamide .

The title compound was prepared as described for Example 1 starting from Example 1C and 1- (4-pyridyl) methylamine . (0.06 g; 27% yield). 1H NMR (CDC13): δ 2.33 (br s, 4H) ,

2.51 (q, 4H, J= 5.8 Hz), 2.73 (app t, 4H) , 3.57 (t, 2H, J= 5.2 Hz), 3.72 (t, 2H, J= 5.2 Hz), 4.47 (d, 2H, J= 6.1

Hz), 6.88 (d, 1H, J= 8.2 Hz), 7.04-7.09 (m, 1H) , 7.16- 7.29 (m, 3H) , 7.34-7.43 (m, 3H) , 7.55-7.60 (m, 2H) , 8.50-

8.52 (m, 2H) . ESI- /MS m/z 443 (M-H) . ESI- /MS /MS m/z 179 (24) , 149 (100) .

Example 4. 3- [2- [4- (2-Biphenyl) piperazin-l-yl] ethoxy] -1- isoindolin-2-yl-propan-l-one .

The title compound was prepared as described for Example 1 starting from Example 1C and 2 , 3-dihydro-lH-iso-indole . (0.13 g; 44% yield). 1H NMR (CDC13): δ 2.33 (br s, 4H) ,

2.47-2.54 (m, 4H) , 2.73 (app t, 4H) , 3.56 (t, 2H, J= 5.5 Hz), 3.71 (t, 2H, J= 5.8 Hz), 4.59 (s, 4H) , 6.88 (d, 1H, J= 7.4 Hz), 6.93-6.95 (m, 4H) , 7.22-7.33 (m, 2H) , 7.37- 7.41 (m, 3H) , 7.54-7.61 (m, 3H) .

Example 5. 1- (3 , 4-dihydro-lH-isoquinolin-2-yl) -3- [2- [4- (2-biphenyl) piperazin-l-yl] ethoxy] propan-l-one .

The title compound was prepared as described for Example 1 starting from Example 1C and 1, 2, 3, 4-tetrahydroiso- indole. (35% yield). 1H NMR (CDC13) : δ 2.35 (br s, 4H) ,

2.48-2.55 (m, 4H) , 2.73 (app t, 4H) , 2.78-2.83 (m, 2H) , 3.56 (t, 2H, J= 5.5 Hz), 3.71 (t, 2H, J= 5.8 Hz), 3.66 (app t, 1H) , 3.82 (app t, 1H) , 4.60 (s, 1H) , 4.72 (s, 1H) , 7.02-7.10 (m, 2H) , 7.12-7.31 (m, 7H) , 7.36-7.41 (m, 2H) , 7.61-7.64 (m, 2H) . Example 6. N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (2- methoxy) phenyl] piperazin-l-yl] ethoxy] propanamide .

6A) 2- [ 4- [ 3- (2 -Methoxy) phenyl ] piperazin-l-yl ] -1-ethanol . The compound was prepared as described for Example 1A starting from 1- [3- (2-Methoxyphenyl) phenyl] piperazine and 2-bromoethanol (0.65 g; 65% yield).

1H NMR (CDC13) : δ 2.09 (br s, 1H, D20 exchanged), 2.61 (t, 2H, J= 5.5 Hz), 2.69 (app t, 4H) , 3.25 (app t, 4H) , 3.66 (t, 2H, J= 5.5 Hz), 3.81 (s, 3H) , 6.90 (dd, 1H, J= 1.9 and 8.2 Hz), 6.96-7.09 (m, 4H) , 7.28-7.34 (m, 3H) . GC/MS: m/z, 313 (M+l, 11), 312 (M+, 50), 281 (100), 238 (27) , 168 (23) .

6B) t-Butyl 3- [2- [4- [3- (2-methoxy) phenyl] piperazin-l- yl ] ethoxy] propanoate .

The compound was prepared as described for Example IB starting from Example 4A and t-butyl acrylate (0.9 g; 40% yield) .

1H NMR (CDC13) : δ 1.45 (s, 9H) , 2.48 (t, 2H, J= 6.4 Hz), 2.52-2.69 (m, 6H) , 2.54 (t, 2H, J= 5.8 Hz), 3.24 (app t, 4H) , 3.63 (t, 2H, J= 5.8 Hz), 3.69 (t, 2H, J= 6.3 Hz), 6.88-7.10 (m, 5H) , 7.29-7.33 (m, 3H) . ESI+/MS m/z 463 (MNa+) . ESI+/MS/MS m/z 407 (100) .

6C) 3- [2- [4- [3- (2-Methoxy) phenyl] piperazin-1- yl ] ethoxy] propanoic acid.

The compound was prepared from Example 4B as described for Example 1C (60% yield) .

1H NMR (CDC13) : δ 2.52 (app t, 2H) , 2.71-2.83 (m, 6H) , 3.06 ( br s, 1H, D20 exchanged), 3.28 (br s, 4H) , 3.64- 3.73 (m, 4H) , 3.79 (s, 3H) , 6.85-6.98 (m, 1H) , 7.01-7.08 (m, 4H) , 7.27-7.33 (m, 3H) . ESI+/MS m/z 385 (MH+) . ESI+/MS/MS m/z 295 (100), 266 (31), 238 (32). 6D) N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [3- (2- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide .

The compound was prepared as described for Example ID starting from 4C and 2-fluoropyridin-5-ylmethylamine (0.06 g; 43% yield). 1H NMR (CDC13): δ 2.53 (t, 2H, J= 5.5 Hz), 2.58-2.71 (m, 6H) , 3.16 (app t, 4H) , 3.63 (t, 2H, J= 5.5 Hz), 3.74 (t, 2H, J= 5.8 Hz), 3.79 (s, 3H) , 4.45 (d, 2H, J= 6.1 Hz), 6.81-6.89 (m, 2H) , 6.96-7.23 (m, 3H) , 7.29-7.34 (m, 3H) , 7.71 (dt, 1H, J= 2.5 and 8.3 Hz), 8.12 (s, 1H) . ESI- /MS m/z 491 (M-H) . ESI- /MS /MS m/z 296 (100) , 164 (8) .

Example 7. N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (2- methyl) phenyl] piperazin-l-yl] ethoxy] propanamide .

7A) 2- [4- [2- (2 -Methyl) phenyl] piperazin-l-yl] -1-ethanol . The compound was prepared as described for Example 1A starting from 1- [2- (2-Methylphenyl) phenyl] piperazine and 2-bromoethanol (0.9 g; 82% yield).

1H NMR (CDC13) : δ 2.09 (br s, 1H, D20 exchanged), 2.18 (s, 3H) , 2.31 (br s, 4H) , 2.44-2.48 (m, 2H) , 2.75-2.80 (m, 2H) , 2.87-2.94 (m, 2H) , 3.55 (t, 2H, J= 5.3 Hz), 7.02-7.19 (m, 5H) , 7.28-7.34 (m, 3H) . GC/MS: m/z, 297 (M+l, 6), 296 (M+, 29), 265 (100), 194 (23).

7B) t-Butyl 3- [2- [4- [2- (2 -methyl) phenyl] piperazin-l- yl ] ethoxy] propanoate .

The compound was prepared as described for Example IB starting from Example 5A and t-butyl acrylate (0.4 g; 33% yield) .

1H NMR (CDC13) : δ 1.43 (s, 9H) , 2.17 (s, 3H) , 2.29 (br s, 4H) , 2.43-2.50 (m, 4H) , 2.74-2.79 (m, 2H) , 2.86-2.92 (m, 2H) , 3.52 (t, 2H, J= 5.8 Hz), 3.64 (t, 2H, J= 6.6 Hz), 7.02-7.19 (m, 5H) , 7.28-7.34 (m, 3H) . ESI+/MS m/z 447 (MNa+) . ESI+/MS/MS m/z 391 (100) . 7C) 3- [2- [4- [2- (2-Methyl) phenyl] piperazin-l- yl ] ethoxy] propanoic acid.

The compound was prepared from Example 5B as described for Example 1C (60% yield) .

1H NMR (CDC13) : δ 2.17 (s, 3H) , 2.30 (br s, 4H) , 2.43- 2.50 (m, 4H) , 2.74-2.79 (m, 2H) , 2.86-2.92 (m, 2H) , 3.52 (t, 2H, J= 5.8 Hz), 3.64 (t, 2H, J= 6.6 Hz), 7.02-7.19 (m, 5H) , 7.28-7.34 (m, 3H) . ESI+/MS m/z 369 (MH+) . ESI+/MS/MS m/z 279 (54), 250 (100), 222 (33).

7D) N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (2- methyl) phenyl] piperazin-l-yl] ethoxy] propanamide .

The compound was prepared as described for Example ID starting from 5C and 2-fluoropyridin-5-ylmethylamine (0.06 g; 43% yield). 1H NMR (CDC13): δ 2.16 (s, 3H) , 2.24

(br s, 4H) , 2.43-2.45 (m, 2H) , 2.48 (t, 2H, J= 5.5 Hz), 2.67-2.71 (m, 2H) , 2.80-2.85 (m, 2H) , 3.52 (t, 2H, J= 5.5 Hz), 3.68 (t, 2H, J= 5.5 Hz), 4.43 (d, 2H, J= 6.1 Hz), 6.86 (dd, 1H, J= 3.0 and 8.5 Hz), 6.94 (d, 1H, J= 8.3 Hz), 7.01-7.13 (m, 3H) , 7.21-7.33 (m, 3H) , 7.72 (dt, 1H, J= 2.5 and 8.0 Hz), 8.10 (s, 1H) . ESI- /MS m/z 476 (M-H) . ESI- /MS /MS m/z 197 (76), 179 (100), 167 (85).

Example 8. N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxy) phenyl] piperazin-l-yl] ethoxy] propanamide .

8A) 2- [4- [2- (4 -methoxy) phenyl] piperazin-l-yl] -1-ethanol . The compound was prepared as described for Example 1A starting from 1- [2- (4-Methoxyphenyl) phenyl] piperazine and 2-bromoethanol (0.65 g; 65% yield).

1H NMR (CDC13) : δ 2.09 (br s, 1H, D20 exchanged), 2.61 (t, 2H, J= 5.5 Hz), 2.69 (app t, 4H) , 3.25 (app t, 4H) , 3.66 (t, 2H, J= 5.5 Hz), 3.84 (s, 3H) , 6.94 (d, 2H, J= 8.8 Hz), 7.00 (d, 1H, J= 8.0 Hz), 7.10-7.15 (m, 1H) , 7.22-7.30 (m, 2H) , 7.46 (d, 2H, J= 8.8 Hz). GC/MS: m/z, 313 (M+l, 11), 312 (M+, 50), 281 (100), 238 (27), 168 (23) . 8B) t-Butyl 3- [2- [4- [2- (4-methoxy) phenyl] piperazin-1- yl ] ethoxy] propanoate .

The compound was prepared as described for Example IB starting from Example 6A and t-butyl acrylate (0.9 g; 40% yield) .

1H NMR (CDC13) : δ 1.45 (s, 9H) , 2.48 (t, 2H, J= 6.4 Hz), 2.52-2.69 (m, 6H) , 2.54 (t, 2H, J= 5.8 Hz), 3.24 (app t, 4H) , 3.63 (t, 2H, J= 5.8 Hz), 3.69 (t, 2H, J= 6.3 Hz), 3.84 (s, 3H) , 6.94 (d, 2H, J= 8.8 Hz), 7.00 (d, 1H, J= 8.0 Hz), 7.10-7.15 (m, 1H) , 7.22-7.30 (m, 2H) , 7.46 (d, 2H, J= 8.8 Hz). ESI+/MS m/z 463 (MNa+) . ESI+/MS/MS m/z 407 (100) .

8C) 3- [2- [4- [2- (4-methoxy) phenyl] piperazin-1- yl ] ethoxy] propanoic acid.

The compound was prepared from Example 6B as described for Example 1C (60% yield). 1H NMR (CDC13) : δ 2.52 (app t, 2H) , 2.71-2.83 (m, 6H) , 3.06 ( br s, 1H, D20 exchanged), 3.28 (br s, 4H) , 3.64-3.73 (m, 4H) , 3.81 (s, 3H) , 6.94 (d, 2H, J= 8.8 Hz), 7.00 (d, 1H, J= 8.0 Hz), 7.10-7.15 (m, 1H) , 7.22-7.30 (m, 2H) , 7.46 (d, 2H, J= 8.8 Hz). ESI+/MS m/z 385 (MH+) . ESI+/MS/MS m/z 295 (100), 266 (31) , 238 (32) . 8D) N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxy) phenyl ] piperazin-l-yl ] ethoxy] propanamide .

The compound was prepared as described for Example ID starting from 6C and 2-fluoropyridin-5-ylmethylamine (0.13 g; 88% yield). 1H NMR (CDC13): δ 2.37 (br s, 4H) , 2.50 (app t, 4H) , 2.78 (br t, 4H) , 3.56 (t, 2H, J= 5.5 Hz), 3.70 (t, 2H, J= 5.5 Hz), 3.84 (s, 3H) , 4.43 (d, 2H, J= 6.3 Hz), 6.86 (dd, 1H, J= 2.9 and 8.4 Hz), 6.94 (d, 2H, J= 8.8 Hz), 7.06 (dt, 1H, J= 1.1 and 7.7 Hz), 7.19- 7.25 (m, 3H) , 7.55 (d, 2H, J= 8.8 Hz), 7.72 (dt, 1H, J= 2.5 and 8.0 Hz), 8.10 (s, 1H) . ESI - /MS m/z 491 (M-H) . ESI- /MS /MS m/z 351 (6), 297 (100). Example 9. N- (2-Bromo-pyridin-5-ylmethyl) -3- [2- [4- [2- (4- methoxy) phenyl] piperazin-l-yl] ethoxy] propanamide .

The compound was prepared as described for Example ID starting from 8C and 2-bromopyridin-5-ylmethylamine (0.15 g; 57% yield). 1H NMR (CDC13): δ 2.37 (br s, 4H) , 2.50 (app t, 4H) , 2.77 (br s, 4H) , 3.56 (t, 2H, J= 5.5 Hz), 3.69 (t, 2H, J= 5.5 Hz), 3.84 (s, 3H) , 4.40 (d, 2H, J= 6.1 Hz), 6.92 (d, 2H, J= 8.5 Hz), 7.06 (t, 1H, J= 7.4 Hz), 7.19-7.24 (m, 2H) , 7.32 (br t, 1H) , 7.41 (d, 1H, J= 8.3 Hz), 7.48 (dd, 1H, J= 2.2 and 8.3 Hz), 7.54 (d, 2H, J= 8.3 Hz), 8.26 (d, 1H, J= 2.5 Hz). ESI- /MS m/z 491 (M- H) . ESI- /MS /MS m/z 351 (6), 297 (100).

Example 10. N-Benzyl-3- [2- [4- [2-biphenyl] piperazin-1- yl] ethoxy] -N-methyl-propanamide

The compound was prepared as described for Example ID starting from 1C and N-benzylmethylamine (40% yield) . 1H NMR (CDC13) : δ 2.35 (br s, 4H) , 2.52 (app t, 4H) , 2.77 (br s, 4H) , 2.90 (s, 3H) , 3.56 (t, 2H, J= 5.5 Hz), 3.69 (t, 2H, J= 5.5 Hz), 3.84 (s, 3H) , 4.40 (d, 2H, J= 6.1

Hz), 6.92 (d, 2H, J= 8.5 Hz), 7.05-7.09 (m, 2H) , 7.14- 7.24 (m, 4H) , 7.32 (br t, 1H) , 7.41 (d, 1H, J= 8.3 Hz), 7.48 (dd, 1H, J= 2.2 and 8.3 Hz), 7.54 (d, 2H, J= 8.3 Hz) , 8.26 (d, 1H, J= 2.5 Hz) .

Example 11. N-Methyl-N- (2-pyridyl) -3- [2- [4- [2- (4- methoxy) phenyl] piperazin-l-yl] ethoxy] propanamide

The compound was prepared as described for Example ID starting from 8C and N-methyl-2-pyridine (20% yield) . 1H NMR (CDC13) : δ 2.37 (br s, 4H) , 2.50 (app t, 4H) , 2.78 (br t, 4H) , 3.56 (t, 2H, J= 5.5 Hz), 3.70 (t, 2H, J= 5.5 Hz), 3.84 (s, 3H) , 4.43 (d, 2H, J= 6.3 Hz), 6.93 (d, 2H, J: 8.8 Hz), 7.00-7.06 (m, 4H) , 7.17-7.23 (m, 2H),7.57 (d, 2H, J: 8.8 Hz), 7.69-7.76 (m, 1H) , 8.45-8.49 (m, 1H) . ESI+/MS m/z 474 (MH+) . Example 12. N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- (2- biphenyl) -1-piperidyl] ethoxy] propanamide

12A) 2- [4- (2-biphenyl) -1-piperidyl] ethanol

The compound was prepared as described for 1A starting from 4- (2-biphenyl) piperidine and 2-bromoethanol (55% yield). 1H NMR (CDC13) : δ 1.66-1.91 (m, 4H) , 2.09 (br s, 1H, D20 exchanged), 2.19-2.29 (m, 4H) , 2.51 (t, 2H, J= 5.3 Hz), 2.78 (m, 1H) , 3.63 (t, 2H, J= 5.3 Hz), 7.02-7.10 (m, 2H) , 7.26-7.32 (m, 3H) , 7.36-7.41 (m, 2H) , 7.61-7.64 (m, 2H) .

12B) t-Butyl 3- [ 2- [ 4- (2-biphenyl ) -1- piperidyl ] ethoxy] propanoate .

The compound was prepared as described for IB starting from 12A. (25% yield). 1H NMR (CDC13) : δ 1.43 (s, 9H) , 1.63-1.95 (m, 4H) , 2.19-2.29 (m, 4H) , 2.47 (t, 2H, J= 6.4 Hz), 2.54 (t, 2H, J= 5.8 Hz), 2.78 (m, 1H) , 3.55 (t, 2H, J= 5.8 Hz), 3.65 (t, 2H, J= 6.4 Hz), 7.02-7.09 (m, 2H) , 7.22-7.31 (m, 3H) , 7.35-7.41 (m, 2H) , 7.61-7.64 (m, 2H) . ESI+/MS m/z 409 (MH+) . ESI+/MS/MS m/z 355 (100) .

12C) 3- [2 - [4 - (2-biphenyl) -1-piperidyl] ethoxy] propanoic acid .

The compound was prepared as described for 1C starting from 12B. 1H NMR (CDC13): δ 1.63-1.95 (m, 4H) , 2.19-2.29 (m, 4H) , 2.47 (t, 2H, J= 6.4 Hz), 2.54 (t, 2H, J= 5.8 Hz), 2.78 (m, 1H) , 3.55 (t, 2H, J= 5.8 Hz), 3.65 (t, 2H, J= 6.4 Hz), 7.02-7.09 (m, 2H) , 7.22-7.31 (m, 3H) , 7.35- 7.41 (m, 2H) , 7.61-7.64 (m, 2H) . ESI+/MS m/z 354 (MH+) .

12D) N- (2-Fluoro-pyridin-5-ylmethyl) -3- [2- [4- (2- biphenyl) -1-piperidyl] ethoxy] propanamide .

The compound was prepared as described for ID starting from 12C and 2-fluoropyridin-5-ylmethylamine (45% yield). 1H NMR (CDC13) : δ 1.70-1.95 (m, 4H) , 2.28-2.35 (m, 4H) , 2.50 (app t, 4H) , 2.78 (m, 1H) , 3.56 (t, 2H, J= 5.5 Hz), 3.70 (t, 2H, J= 5.5 Hz), 4.43 (d, 2H, J= 6.3 Hz), 6.86 (dd, 1H, J= 2.9 and 8.4 Hz), 6.94 (d, 2H, J= 8.8 Hz), 7.06 (dt, 1H, J= 1.1 and 7.7 Hz), 7.19-7.25 (m, 4H) , 7.55 (d, 2H, J= 8.8 Hz), 7.72 (dt, 1H, J= 2.5 and 8.0 Hz), 8.10 (s, 1H) . ESI+/MS m/z 462 (MH+) .

Example 13. N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4- methoxy) henyl] -1-piperazinehexanamide .

13A) 6-Bromo-N- (2-fluoro-pyridin-5-ylmethyl) hexanamide . A cooled solution of 2-fluoropyridin-5-ylmethylamine (0.18 g; 1.4 mmol) in CH2C12 was stirred vigorously with 2% aqueous NaOH (5.6 mL, 1.7 mmol) while 6-bromohexanoyl chloride (0.36 g; 1.7 mmol) in CH2C12 was added dropwise. The same NaOH solution was then used to maintain pH at 9, and at costant pH the layers were separated. The organic phase was washed with 3 N HC1, with H20, and then dried over Na2S04 and evaporated under reduced pressure. The crude residue was chromatographed (CHC13/AcOEt , 1:1, as eluent) to give pure compound as orange oil (0.2 g; 49% yield). 1H NMR (CDC13) : δ 1.44-1.52 (m, 2H) , 1.64-1.74 (m, 2H) , 1.82-1.90 (m, 2H) , 2.24 (t, 2H, J= 7.5 Hz), 3.40

(t, 2H, J= 6.6 Hz), 3.84 (s, 3H) , 4.43 (d, 2H, J= 6.1 Hz), 6.90 (dd, 1H, J= 2.8 and 8.5 Hz), 7.76 (dt, 1H, J= 2.5 and 7.7 Hz), 8.12 (dd, 1H, J= 0.8 and 1.4 Hz) . ESI+/MS m/z 304 (M-H) . ESI+/MS/MS m/z 245 (20), 223 (100) .

13B) N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4- methoxy) phenyl ] -1-piperazinehexanamide .

A stirred mixture of Example 8A (0.2 g; 0.7 mmol), l-[2- (4-methoxyphenyl) phenyl] piperazine (0.16 g; 0.6 mmol) and K2C03 (0.7 mmol) in acetonitrile was refluxed overnight. After cooling, the mixture was evaporated to dryness and H20 (20 mL) was added to the residue. The aqueous phase was extracted with AcOEt (2 ^χ 30 mL) . The collected organic layers were dried over Na2S04 and evaporated under reduced pressure. The crude residue was chromatographed (CHC13/MeOH, 19:1, as eluent) to afford pure compound as a thick yellow oil (0.23 g; 80% yield) . 1H NMR (CDC13) : δ 1.28-1.36 (m, 2H) , 1.46-1.51 (m, 2H) , 1.61-1.71 (m, 2H) , 2.21 (t, 2H, J= 7.7 Hz), 2.30 (app t, 2H) , 2.36 (br s, 4H) , 2.86 (app. t, 4H) , 3.85 (s, 3H) , 4.42 (d, 2H, J= 6.1 Hz), 5.90 (br t, 1H) , 6.87-6.95 (m, 3H) , 7.05 (q, 2H, J= 7.7 Hz), 7.19-7.27 (m, 2H) , 7.54- 7.59 (m, 2H) , 7.75 (dt, 1H, J= 2.5 and 7.7 Hz), 8.12 (d, 1H, J= 1.4 Hz). ESI+/MS m/z 513 (MNa+) . ESI+/MS/MS m/z 365 (15) , 223 (100) .

Example 14. N- (2-Fluoro-pyridin-5-ylmethyl) -4- [2- (4- pyridyl) pyridyl] -1-piperazinehexanamide .

The compound was prepared as described for Example 13B starting from 13A and 1- [2- (4-pyridyl) pyridyl] piperazine (0.07 g; 17% yield). 1H NMR (CDC13): δ 1.28-1.36 (m, 2H) ,

1.46-1.51 (m, 2H) , 1.61-1.71 (m, 2H) , 2.21 (t, 2H, J= 7.7 Hz), 2.30 (app t, 2H) , 2.36 (br s, 4H) , 2.86 (app. t, 4H) , 4.42 (d, 2H, J= 6.1 Hz), 5.90 (br t, 1H) , 6.87-6.95 (m, 3H) , 7.05 (q, 2H, J= 7.7 Hz), 7.19-7.27 (m, 2H) , 7.54-7.59 (m, 2H) , 7.75 (dt, 1H, J= 2.5 and 7.7 Hz), 8.12 (d, 1H, J= 1.4 Hz). ESI+ /MS m/z 485 (MNa+) . ESI+/MS/MS m/z 485 (100) , 376 (6) .

Example 15. N- (2-Fluoro-pyridin-5-ylmethyl) -4- [3- (4- pyridyl) pyridyl] -1-piperazinehexanamide.

The compound was prepared as described for Example 13B starting from 13A and 1- [3- (4-pyridyl) pyridyl] piperazine (0.14 g; 52% yield). 1H NMR (CDC13): δ 1.28-1.36 (m, 2H) , 1.46-1.51 (m, 2H) , 1.61-1.71 (m, 2H) , 2.21 (q, 2H, J= 7.7 Hz), 2.30 (app t, 2H) , 2.36 (br s, 4H) , 2.86 (app. t, 4H) , 4.40-4.42 (m, 2H) , 5.90 (br t, 1H) , 6.87-6.95 (m, 3H) , 7.05 (q, 2H, J= 7.7 Hz), 7.19-7.27 (m, 2H) , 7.54- 7.59 (m, 2H) , 7.75 (dt, 1H, J= 2.5 and 7.7 Hz), 8.12 (d, 1H, J= 1.4 Hz). ESI+/MS m/z 485 (MNa+) . ESI+/MS/MS m/z 485 (100) , 376 (6) . Example 16. 2- [6- [4- [3- (4-pyridyl) pyridyl] -1- piperazinyl] -1-oxohexyl] isoindoline.

The compound was prepared as described for Example 13B starting from N- ( 6-Bromo-l-oxohexyl) isoindoline (J. Med. Chem. 2008, 51, 5813) and 1- (2-biphenyl) piperazine . 60% Yield. 1H NMR (CDC13) : δ 1.33-1.43 (m, 2H) , 1.49-1.59 (m, 2H) , 1.72 (quintet, 2H, J= 7.4 Hz), 2.32-2.39 (m, 8H) ,

2.88 (app t, 4H) , 4.79 (s, 4H) , 6.68 (t, 1H, J: 8.0 Hz), 6.94-7.00 (m, 4H) , 7.60-7.68 (m, 3H) , 8.05 (d, 1H, J= 7.7 Hz), 8.65 (d, 2H, J= 7.7 Hz) .

Example 17. 2- [6- [4- [2- (4-Methoxyphenyl) phenyl) -1- piperazinyl] -1-oxohexyl] -1 , 2 , 3 , 4-tetrahydroisoquinoline .

The compound was prepared as described for Example 13B starting from N- ( 6-Bromo-l-oxohexyl ) -1 , 2 , 3 , 4- tetrahydroisoquinoline (J. Med. Chem. 2008, 51, 5813) and 1- (2-biphenyl) piperazine . 48% Yield. 1H NMR (CDC13) : δ 1.30-1.43 (m, 2H) , 1.47-1.52 (m, 2H) , 1.61-1.73 (m, 2H) , 2.36-2.42 (m, 8H) , 2.82-2.88 (m, 6H) , 3.66 (app t, 1H) , 3.73 (s, 3H) , 3.82 (app t, 1H) , 4.60 (s, 1H) , 4.72 (s, 1H) , 7.02-7.10 (m, 2H) , 7.12-7.31 (m, 6H) , 7.36-7.41 (m, 2H) , 7.61-7.64 (m, 2H) .

Example 18. N-Methyl-6- [4- [2- (4-methoxyphenyl) phenyl] -N- (2-pyridyl) -1-piperazinehexanamide .

18A) 6-Bromo-N-methyl-N- (2-pyridyl) hexanamide .

The compound was prepared as reported for 8A starting from N-methyl-2-pyridine and 6-bromohexanoylchloride . (18% yield) . 1H NMR (CDC13) : δ 1.47-1.56 (m, 2H) , 1.64- 1.73 (m, 2H) , 1.85-1.95 (m, 2H) , 2.38 (t, 2H, J= 7.2 Hz),

2.89 (s, 3H) , 3.42 (t, 2H, J: 6.9Hz) , 6.42 (d, 1H, J: 8.8 Hz), 6.55-6.59 (m, 1H) , 7.51-7.57 (m, 2H) , 7.990-7.92 (m, 1H) .

18B) N-Methyl-6- [4- [2- ( 4 -methoxyphenyl ) phenyl ] -N- (2- pyridyl) -1-piperazinehexanamide.

The compound was prepared as reported for 8B starting from xA and 1- [2- (4-methoxyphenyl) phenyl] piperazine . (25% yield). 1H NMR (CDC13) : δ 1.47-1.56 (m, 2H) , 1.64-1.73 (m, 2H) , 1.85-1.95 (m, 2H) , 2.22-2.45 (m, 6H) , 2.85 (app. t, 4H) , 3.36 (s, 3H) , 3.85 (s, 3H) , 6.93 (d, 2H, J: 8.8 Hz), 7.00-7.06 (m, 4H) , 7.17-7.23 (m, 2H),7.57 (d, 2H, J: 8.8 Hz), 7.69-7.76 (m, 1H) , 8.45-8.49 (m, 1H) . ESI+/MS m/z 473 (MH+) . ESI+/MS/MS m/z 365 (100), 266 (20).

Example 19. 4- (2-Biphenyl) -N- (4-pyridinylmethyl) -1- piperidinehexanamide .

The compound was prepared as described for 13B starting from 6-Bromo-N- (4-pyridinylmethyl) hexanamide (J. Med. Chem. 2008, 51, 5813) and 4- (2-biphenyl) piperidine (72% yield). 1H NMR (CDC13) : δ 1.28-1.38 (m, 2H) , 1.43-1.54 (m, 2H) , 1.66-1.91 (m, 4H) , 2.19-2.29 (m, 4H) , 2.25 (t, 2H, J: 7.4Hz), 2.31-2.33 (m, 2H) , 2.35 (br s, 4H) , 2.78 (m, 1H) , 4.44 (d, 2H, J ) 6.1 Hz), 6.00 (br t, 1H, D20 exchanged), 7.01-7.09 (m, 2H) , 7.16-7.18 (m, 2H) , 7.22- 7.31 (m, 3H) , 7.36-7.41 (m, 2H) , 7.60-7.64 (m, 2H) , 8.54 (dd, 2H, J: 1.7, 4.4 Hz). ESI+/MS m/z 444 (MH+) .

Example 20. N- [ (4-Cyanophenyl) methyl] -3- [ [1- (2-biphenyl) - 4-piperidyl] methylamino] propanamide .

The compound was prepared as described for 13B starting from 3-chloro-N- (4-pyridinylmethyl) propanamide and [l-(2- biphenyl) -4-piperidyl] methylamine (25% yield). 1H NMR (CDC13) : δ 1.34-1.59 (m, 4H) , 1.73 (m, 1H) , 2.30 (t, 2H, J: 7.4 Hz), 2.45-2.51 (m, 2H) , 2.75-2.83 (m, 6H) , 4.46 (d, 2H, J: 6.1 Hz), 6.00 (br t, 1H, D20 exchanged), 7.00- 7.10 (m, 2H) , 7.22-7.31 (m, 3H) , 7.33-7.41 (m, 4H) , 7.58- 7.64 (m, 4H) . ESI+/MS m/z 453 (MH+) .

Example 21. l-Isoindolin-2-yl-3- [ [1- (2-biphenyl) -4- piperidyl] methylamino] propan-l-one .

The compound was prepared as described for 13B starting from from N- (3-chloro-l-oxopropyl) isoindoline and [l-(2- biphenyl) -4-piperidyl] methylamine (25% yield). 1H NMR (CDC13) : δ 1.34-1.59 (m, 4H) , 1.73 (m, 1H) , 2.30 (t, 2H, J: 7.4 Hz), 2.45-2.51 (m, 2H) , 2.75-2.83 (m, 6H) , 4.46 (d, 2H, J: 6.1 Hz), 6.00 (br t, 1H, D20 exchanged), 6.85- 6.94 (m, 4H) , 7.00-7.10 (m, 2H) , 7.22-7.31 (m, 3H) , 7.33- 7.41 (m, 4H) . ESI+/MS m/z 440 (MH+) .

BIOLOGICAL TESTING

Radioligand binding assay at human cloned 5-HT ₇ receptors .

Functionality assays on the 5-HT7 receptor were done according to Jasper et al [Br. J. Pharmacol. 1997, 122, 126.] with minor modifications. The test is a competition assay based on binding of [ ³ H] -5-CT at human cloned 5-HT ₇ receptor . In 0.5 mL of incubation buffer (50 mM Tris- HC1, 10 mM MgS0 ₄ and 0.5 mM EDTA, pH 7.4) were suspended 34 yg of membranes, 1.5 nM [ ³ H] -5-CT, the drugs or reference compound (six to nine concentrations) . The samples were incubated for 120 min at 27 °C. The incubation was stopped by rapid filtration on Whatman GF/C glass microfiber filters (pre-soaked in 0.3% polyethylenimine for 30 min) . The filters were washed with 3 x 1 mL of ice-cold buffer (50 mM Tris-HCl, pH 7.4) . Nonspecific binding was determined in the presence of 10 μΜ 5-CT. Approximately 90% of specific binding was determined under these conditions.

Radioligand binding assay at human cloned 5-HTi _A receptor .

Human 5-HTi _A serotonin receptors stably expressed in HEK293-EBNA cells were radiolabeled with 1.0 nM [ ³ H] -8- OH-DPAT [J. Biol. Chem. 1989, 264, 14848]. Samples containing 32 yg of membrane protein, different concentrations of each compound ranging from 0.1 nM to 10 μΜ were incubated in a final volume of 500 yL of 50 mM Tris-HCl pH 7.4, 5 mM MgS0 ₄ for 120 min at 37 °C. After this incubation time, samples were filtered through Whatman GF/C glass microfiber filters pre-soaked in polyethylenimine 0.5% for at least 30 min prior to use. The filters were washed twice with 1 ml of ice-cold buffer (50 mM Tris-HCl, pH 7.4) . Nonspecific binding was determined in the presence of 10 μΜ 5-HT.

Competition binding data were analyzed using the GraphPad Prism Software (GraphPad Software, Inc., San Diego, CA, USA) . The value for the inhibition constant, Ki, was calculated by using the Cheng-Prusoff equation [Anal. Biochem. 1980, 107, 200-239] .

Determination of in vitro metabolic stability using liver S9 fractions.

Tested compounds (10 μΜ) were incubated with rat liver S9 fractions (1 mg/ml) , liver S9 fractions are subcellular fractions that contain drug-metabolizing enzymes such as cytochromes P450, flavin monooxygenases , and UDP glucuronyl transferases.

The incubation was performed in 100 mM phosphate buffer (pH 7.4) containing 1.3 mM of NADP+ , 3.3 mM glucose 6- phosphate and 0.4 U/ml glucose 6-phosphate dehydrogenase, 3.3 mM MgC12 in a total volume of 1 mL . Incubations were commenced with the addition of glucose 6-phosphate dehygrogenase and carried out for 30 min. at 37 °C. The reaction was stopped by adding 1 mL of cooled acetonitrile . The samples were centrifuged at 4600 rpm for 10 min at 4 °C. The supernatant was separated and the acetonitrile phase was analyzed by using a reversed-phase HPLC equipped with a Perkin-Elmer series 200 LC pump and a Perkin-Elmer 785A UV/VIS detector. UV signals were monitored and obtained peaks integrated using a personal computer running Perkin-Elmer Turbochrom Software. The column used was a Phenomenex Gemini C-18 (250 x 4.6 mm, 5 μιη particle size) . The samples were eluted with ammonium formate (20 mM; pH 6.7) and acetonitrile 80:20 v/v at a flow rate of 1 mL/min and at the appropriate UV wavelength. The sample injection volume was 20 μΐ, . This assay provides information on the xenobiotic metabolism of the tested compounds; the results obtained are reported in table 1.

Evaluation of inhibition activity of the compounds

The compounds were active at 5-HT7 receptors because they showed Ki values lower than 100 nM in the radioligand binding assay.

Biological data on several compounds of the present invention are reported in Table 1.

Table 1.

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