WO1999038866A1

WO1999038866A1 - 8-azabicyclo[3.2.1]oct-2-ene derivatives in labelled form and use of 8-azabicyclo[3.2.1]oct-2-ene derivatives in labelled and unlabelled form

Info

Publication number: WO1999038866A1
Application number: PCT/DK1999/000044
Authority: WO
Inventors: Peter Moldt; Jørgen SCHEEL-KRÜGER; Elsebet Østergaard NIELSEN
Original assignee: Neurosearch A/S
Priority date: 1998-01-28
Filing date: 1999-01-28
Publication date: 1999-08-05
Also published as: AU2609999A; EP1068204A1; WO1999038866A8; JP2002501921A; ZA99681B

Abstract

The present invention relates to 8-azabicyclo[3.2.1]oct-2-ene derivatives in their labelled form. Furthermore, the present invention relates to the use of said derivatives in their labelled or unlabelled form in diganostic methods, in particular for in vivo receptor imaging (neuroimaging).

Description

8-AZABICYCL0[3.2. 1]0CT-2-ENE DERIVATIVES IN LABELLED FORM AND USE OF 8- AZABICYCL0[3. 2. 1]0CT-2-ENE DERIVATIVES IN LABELLED AND UNLABELLED FORM

TECHNICAL FIELD

The present invention relates to 8-azabicyclo[3.2.1]oct-2-ene derivatives in their labelled and unlabeiled form. Furthermore, the present invention relates to the use of said derivatives in their labelled or unlabeiled form in diagnostic methods, in particular for in vivo receptor imaging (neuroimaging).

BACKGROUND ART

WO 9713770 discloses 8-azabicyclo[3.2.1]oct-2-ene derivatives which are re-uptake inhibitors for the monoamine neurotransmitter serotonine (5-hydroxy- tryptamine, 5-HT) and therefore useful in the treatment of disorders or diseases which are caused, at least in part, by increase or decrease of the endogenous serotonine levels. Such disorders or diseases are e.g., depression and related disorders, obsessive compulsive disorders, panic disorders, memory deficits, attention deficit, hyperactivity disorder, obesity, anxiety and eating disorders.

Monoamine neurotransmitters (i.e. serotonine, dopamine, and noradrenaline) are produced in neurons and are released into the synaptic cleft upon stimulation of the presynaptic neuron. The neurotransmitter molecules can diffuse through the cleft and then bind to specific receptor molecules (transporters) located in the postsynaptic cell membrane. Binding to these receptors results in polarisation of the cell, i.e. transduction of the stimulus. The removal (or inactivation) of monoamine neurotransmitters from the synaptic cleft occurs mainly by a re-uptake mechanism into presynaptic nerve terminals. By inhibiting the re-uptake an enhancement of the physiological activity of monoamine neurotransmitters occurs. Major depression is a common disorder, affecting approximately 1 in 6 individuals at some point in their lives. The pathophysiology of depression is poorly understood so far, and several neurotransmitters have been implicated in the pathophysiology of major depression. Inhibitors that block noradrenaline and serotonine re-uptake are currently used as pharmaceuticals in anti-depressant therapy. Several lines of preclinical and clinical evidence indicate that an enhancement of serotonine-mediated neurotransmission might underlie the therapeutic effect of the most recent and currently used drugs in anti-depressant therapy, such as fluoxetine, citalopram and paroxetine [P. Blier & C de Montigney, TiPS (Review) 1994 15 220-225].

Paradoxically, serotonine re-uptake inhibitors block the serotonine transporter within minutes after application whereas their full anti-depressant effect is seen only after three to four weeks of treatment, indicating that re-uptake inhibition per se is not responsible for the anti-depressant response, but rather that further adaptive changes underlie and/or contribute to their therapeutic effect [P. Willner, Int. Review of Psychiatry 1990 2 141-156].

The serotonergic neural system of the brain has been shown to influence a variety of physiologic functions, and disturbance of this system has been made responsible for a variety of diseases and disorders such as eating disorders, depression, obsessive compulsive disorders, panic disorders, alcoholism, pain, memory deficits and anxiety. Included among these disorders are depression and related disorders such as pseudodementia or Ganser's syndrome, migraine, pain, bulimia, obesity, pre-menstrual syndrome or late luteal phase syndrome, alcoholism, tobacco abuse, panic disorder, anxiety, post-traumatic syndrome, memory loss, dementia of ageing, social phobia, attention deficit hyperactivity disorder (ADHD syndrome), chronic fatigue syndrome, premature ejaculation, erectile dysfunction, anorexia nervosa, disorders of sleep, autism, mutism or trichotillomania.

Currently the standard method for the diagnosis of depression is a consultation between physician e.g., psychiatrists and patient in order to evaluate the patient's emotional life. It is characteristic for depressed patients e.g. to lack initiative and interest, to possess a general feeling of sadness, and to have a feeling of guilt and worthlessness, to lack appetite and libido, and to suffer from sleeplessness. These symptoms can occur temporarily and with different intensity which makes it very difficult to determine the appropriate diagnosis and therapy. Therefore, psychiatrists have looked for objective laboratory or clinical tests that could confirm the diagnosis and possibly predict a response to treatment. Recent research has focused on the biochemical backgrounds of the depression syndrome. It has been found that measurements of the regional cerebral blood-flow (rCBF) can be used to diagnose depression. In brains of depressed patients three areas showed significantly reduced rCBF (left dorsolateral prefrontal cortex, the left anterior cingulate cortex and the left angular gyms). When depression is combined with cognitive impairment a decreased rCBF in the left medial prefrontal cortex and increased rCBF in the right cerebral vermis has been detected [Bench CJ, Friston KJ, Brown RG, Scott LC, Frackowiak RS & Dolan RJ: The anatomy of melancholia-focal abnormalities of cerebral blood flow in major depression; Psvchol- Med. 1992 22 (3) 607-15; and Dolan RJ, Bench CJ, Brown RG, Scott LC, Friston KJ & Frackowiak-RS: Regional cerebral blood flow abnormalities in depressed patients with cognitive impairment; J. Neurol. Neurosurα. Psychiatry. 1992 55 (9) 768-73]. This method enables a physician to reliably detect a parameter that seems to correlate at least in a number of cases with pathologic depression. However, treatment with anti- depressant drugs is not reflected in changes of the rCBF, which means that a therapeutic effect can not be monitored by this method.

The study of serotonine re-uptake sites using emission tomography requires the use of radioligands which have desirable properties for in vivo receptor imaging. These criteria include ease of labelling with positron-emitting radionucleotides, low rates of peripheral metabolism, high selectivity for brain regions holding the neuroreceptor of interest, and relatively high specific/non-specific binding ratios. Despite the development of a number of radioligands for the serotonine transporter, none of these compounds satisfactorily meet all the criteria desired for an ideal ligand.

SUMMARY OF THE INVENTION The compounds and their derivatives of this invention are the first substances known that specifically bind to serotonine transporters. This allows for the first time to reliably determine the number of serotonine binding sites and related Kd values and the release of serotonine as well as the detection of changes in the serotonine metabolism in response to therapeutic drugs.

It is therefore an object of the present invention to provide a compound which can be used to diagnose diseases or disorders that are related to changes in the serotonine levels in vivo and in vitro and which can be used as well to monitor the effect of a therapy. Further, it is an object of the present invention to provide methods for diagnosing several disorders linked to decreased or increased neurotransmission of serotonine in vivo and in vitro using a specific detectable compound.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further illustrated by reference to the accompanying drawing, in which:

Fig. 1 shows a characteristic PET scan illustrating the unique and very specific uptake and labelling of serotonine nerve terminals (containing the serotonine reuptake transporter) by Compound (3-4) of the invention; A coronal (left), transaxial (centre) and sagittal (right) section of a pig brain labelled with Compound (3-4). Accumulation of the compound can be seen in the medial mesecephalon (the serotonergic Raphe nuclei) and in the diecephalon (the thalamus and basal ganglia).

DETAILED DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a compound which can be used to diagnose diseases or disorders that are related to changes in the serotonine levels in vivo and in vitro and which can be used as well to monitor the effect of a therapy. This object is solved by providing a labelled or unlabeiled compounds derived from a compound having the formula (I): R"

R

It is an object of the present invention to provide a compound which can be used to diagnose diseases or disorders that are related to changes in the serotonine levels in vivo and in vitro and which can be used as well to monitor the effect of a therapy. This object is solved by providing a labelled compound derived from a compound having the formula (I):

R⁴

R or any of its enantiomers or any mixture thereof, or a pharmaceutically acceptable salt thereof; wherein

R is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl or 2- hydroxyethyl; and R⁴ is phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; 3,4-methylenedioxyphenyl; benzyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; heteroaryl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; naphthyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; or a fluorescent group.

Definition of Substituents In the context of this invention halogen represents a fluorine, a chlorine, a bromine or a iodine atom.

In the context of this invention an alkyl group designates a univalent saturated, straight or branched hydrocarbon chain. The hydrocarbon chain preferably contain of from one to eighteen carbon atoms (C^s-alkyl), more preferred of from one to six carbon atoms (C₁.₆-alkyl; lower alkyl), including pentyl, isopentyl, neopentyl, tertiary pentyl, hexyl and isohexyl. In a preferred embodiment alkyl represents a C_1-4-alkyl group, including butyl, isobutyl, secondary butyl, and tertiary butyl.

In the context of this invention a haloalkyl group designates an alkyl as above, mono- or polysubstituted with halogen as above. This includes e.g. (X designates a halogen as above) CX₃, CHX₂, CH₂X, CH₂CX₃, CH₂CH₂X, XCHCH₂X,

C₃H₆X, C₃H₅X₂, C₃H₄X₃, C₃H₃X₄, C₃H₂X₅, C₃X₇ etc. Preferred groups are C ₄- haloalkyl containing one halogen; Especially preferred groups are -CH₂F, -CH₂I, -

C₂H₅I, -C₂H₅F, -C₃H₆I, -C₃H₆F, and -CF₃. In the context of this invention a cycloalkyl group designates a cyclic alkyl group, preferably containing of from three to seven carbon atoms (C₃.₇-cycloalkyl), including cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

In the context of this invention an alkenyl group designates a carbon chain containing one or more double bonds, including di-enes, tri-enes and poly- enes. In a preferred embodiment the alkenyl group of the invention comprises of from two to six carbon atoms (C₂.₆-alkenyl), including at least one double bond. In a most preferred embodiment the alkenyl group of the invention is ethenyl; 1- or 2- propenyl; or 1-, 2-, or 3-butenyl.

In the context of this invention a haloalkenyl group designates a alkenyl group as above mono- or polysubstituted with halogen as above. In a preferred embodiment of the invention the haloalkenyl represents from 2 to 4 carbons substituted with halogen such as e.g. -CH₂CH=CHI, -CH₂CH=CHF, -CH=CHF, -

CH=CHI, -CF=CH₂, CH=CF₂, -CH=CHCH₂I, -CH=CHCH₂F, -CH=CH-CH=CHI, -

CH=CH-CH=CHF, -CH₂CH₂CH=CHI, -CH₂CH₂CH=CHI, etc.

In the context of this invention an alkynyl group designates a carbon chain containing one or more triple bonds, including di-ynes, tri-ynes and poly-ynes. In a preferred embodiment the alkynyl group of the invention comprises of from two to six carbon atoms (C_2-6-alkynyl), including at least one triple bond. In its most preferred embodiment the alkynyl group of the invention is ethynyl, 1 ,2- or 2,3-propynyl, 1 ,2-,

2,3- or 3,4-butynyl. In the context of this invention a haloalkynyl group is alkynyl as above substituted with one or more halogen as above. Examples are e.g. -C≡C-CH₂I, -

C≡C-CH₂F, -C≡C-CH₂CI, -CHI-C≡CH, -CHF-C≡CH, -CHCI-C≡CH, -CH₂C≡C-CH₂I, -

CH₂C≡C-CH₂CI, -CH₂C≡C-CH₂F, etc.

In the context of this invention a cycloalkyl-alkyl group designates a cycloalkyl group as defined above, which cycloalkyl group is substituted on an alkyl group as also defined above. Examples of preferred cycloalkyl-alkyl groups of the invention include cyclopropylmethyl and cyclopropylethyl.

In the context of this invention an alkoxy group designates an "alkyl-O-" group, wherein alkyl is as defined above. In the context of this invention an alkoxy-alkyl group designates an "alkyl-

O-aikyl-" group, wherein alkyl is as defined above.

In the context of this invention an amino group may be a primary (-NH₂), secondary (-NH-alkyl), or tertiary (-N(alkyl)₂) amino group, i.e. it may be substituted once or twice with an alkyl group as defined above. In the context of this invention a thioalkyl group is -alkyl-SH wherein alkyl is as defined above. In the context of this invention a thioalkenyl group is -alkenyl-SH wherein alkenyl is as defined above.

In the context of this invention a thioalkynyl group is alkynyl-SH wherein alkynyl is as defined above. Examples of preferred aromatic heterocyclic monocyclic groups of the invention include 1 ,3,2,4- or 1 ,3,4,5-dioxadiazolyl, dioxatriazinyl, dioxazinyl, 1 ,2,3-,

1 ,2,4-, 1 ,3,2- or 1 ,3,4-dioxazolyl, 1 ,3,2,4- or 1 ,3,4,5-dithiadiazolyl, dithiatriazinyl, dithiazinyl, 1 ,2,3-dithiazolyl, furanyl, furazanyl, imidazolyl, isoimidazolyl, 2- isoimidazolyl, isoindazolyl, isothiazolyl, isoxazolyl, 1 ,2,3-, 1 ,2,4-, 1 ,2,5- or 1 ,3,4- oxadiazolyl, oxatetrazinyl, oxatriazinyl, 1 ,2,3,4- or 1 ,2,3,5-oxatriazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl (azolyl), 1 ,2,3,4- or

2,1 ,3,4-tetrazolyl, thiadiazolyl, thiazolyl, thienyl, 1 ,2,3-, 1 ,2,4- or 1 ,3,5-triazinyl, and

1 ,2,3-, 1 ,2,4-, 2,1 ,3- or 4,1 ,2-triazolyl, furan-2-yl, furan-3-yl, 2-, 4- or 5-imidazolyl, 3-,

4- or 5-isoxazolyl, 1 -, 2- or 3-pyridinyl, and 1- or 2-thienyl. In the context of this application, "label" stands for the binding of a marker to the compound of interest that will allow easy quantitative detection of said compound.

The labelled compound of the present invention preferably contains at least one radionuclide as a label. Positron emitting radionuclides are all candidates for usage. In the context of this invention the radionuclide is preferably selected from ¹¹C, ¹⁸F, ¹⁵0, ¹³N, ¹²³l, ¹²⁵l, ¹³¹l , ³H and ^99m Tc.

The fluorescent group of the compound of formula (I) can be selected from the group of naturally occurring fluorophores or chemically synthesized fluorescent groups, such as rhodamine, green fluorescent protein or fluorescein and its derivatives.

In the compound of formula (I) R is preferably hydrogen, an alkyl group having 1 to 6 C atoms, haloalkyl, haloalkenyl and R⁴ is preferably a phenyl group which may be substituted one or more times. The substituents are preferably selected from I, F, Cl, CF₃, CH₃, and OCH₃. Preferred compounds of the invention are:

(±)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (+)-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-chlorophenyl)-8-azabicyclo[3.2.1]oct-2-ene; (±)-3-phenyl-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-phenyl-8-azabicyclo[3.2.1 ]oct-2-ene;

(±)-3-(4-methylphenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-methylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (±)-3-(4-methoxyphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-trif luoromethylphenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene;

(±)-3-(4-trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-f luorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; or (±)-3-(4-f luorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; which are labelled with at least one nuclide selected from ¹¹C, ¹⁸F and ¹³N, or a pharmaceutically acceptable salt of said labelled compound.

Other preferred compounds of formula (I) are compounds wherein R represents a haloalkenyl such as 1-iodo-prop-1-en-3-yl, wherein the iodine is a radioactive isotope of iodine and R⁴ represents phenyl substituted with Cl F, CH₃, CF₃, Cl, H; or R⁴ represents 3,4-dichlorophenyl. Further preferred compounds are compounds of formula(l) wherein R represents a haloalkyl such as methyliodine, ethyliodine, propyliodine, methylflouride, ethylfluoride, propylfluoride wherein the halogen is optionally a radioactive isotope of iodine or fluoride and R⁴ represents phenyl substituted with Cl F, CH₃, CF₃, Cl, H; or R⁴ represents 3,4-dichlorophenyl. Other preferred compounds are compounds of formula(l) wherein R represents a alkylthio-derivative such as thiomethyl, ethylthio, propylthio, butylthio and R⁴ represents phenyl substituted with F, CH₃, CF₃, Cl, H; or R⁴ represents 3,4- dichlorophenyl;. These compounds are suitable for co-ordinating to a Tc complex [Meegall S, et al.; Bioconiuαate Chem. 1996 7421-429].

Steric isomers It will be appreciated by those skilled in the art that some compounds of formula (I) contain chiral centres and that such compounds exist in the form of isomers (i.e. enantiomers). The invention includes all such isomers and any mixtures thereof including racemic mixtures.

Some of the compounds of formula (I) exist in (+) and (-) forms as well as in racemic forms. Racemic forms can be resolved into the optical antipodes by known methods, for example, by separation of diastereomeric salts thereof with an optically active acid, and liberating the optically active amine compound by treatment with a base. Another method for resolving racemates into the optical antipodes is based upon chromatography on an optically active matrix. Racemic compounds of the present invention can thus be resolved into their optical antipodes, e.g., by fractional crystallisation of d- or I- (tartrates, mandelates, or camphorsulphonate) salts. The compounds of formula (I) may also be resolved by the formation of diastereomeric amides by reaction of the compounds of formula (I) with an optically active activated carboxylic acid such as that derived from (+) or (-) phenylalanine, (+) or (-) phenylglycine, (+) or (-) camphanic acid or by the formation of diastereomeric carbamates by reaction of the compounds of formula (I) e.g. with an optically active chloroformate. Additional methods for the resolvation of optical isomers, known to those skilled in the art may be used, and will be apparent to the average person skilled in the art. Such methods include those discussed by Jaques, J et al. [Jaques J, Collet A, and Wilen S; in Enantiomers. Racemates. and Resolutions. John Wiley and Sons, New York, 19819.

Preparatory methods

The labelled compounds of the invention may be prepared in numerous ways. The labelled compounds of the invention and their pharmaceutically acceptable derivatives may thus be prepared by any method known in the art for the preparation of compounds of analogous structure, provided that a label, preferably a radionuclide, is incorporated by suitable means.

The labelled compounds of the present invention can be prepared in the same way as the unlabeiled compounds of formula (I) except that at least one of the materials used for the preparation of the compounds of formula (I) comprises a label, preferably a radionuclide, which label is inserted into the final compound. Alternatively, a group of an unlabeiled compound of formula (I) can be exchanged by a labelled group, thereby forming a labelled compound of formula (I).

The unlabeiled compounds of formula (I) can for example be prepared according to the methods disclosed in WO 97/13770, for example as in the following scheme (1).

Scheme (1):

R -Br X-alkyl R -X

R R

N N

I I

R R

The substituents R and R in the formulae of scheme (I) are as defined above and X is Li, MgBr or any other type of functional group suitable for generating a carbanion as its counterpart.

The processes in the reaction scheme above are carried out in conventional manner. The dehydration of the alcohol is affected using acids such as hydrochloric or sulphuric acid or other conventional dehydrating agents such as for example P₂0₅ or SOCI₂.

An unlabeiled compound of formula (I) can be converted to another unlabeiled compound of formula (I) using conventional methods.

The materials used in the preparation of unlabeiled compounds of formula (I) are known or can be prepared by known processes from commercially available materials.

The products of the reactions described herein can be isolated by conventional means, such as extraction, crystallisation, distillation and/or chromatography. The labelled compounds of formula (I) can generally be prepared in the same way as described above for the unlabeiled compounds of formula (I). In this case, any of the materials used for the preparation of the unlabeiled compound of formula (I) can be labelled, preferably by a radionuclide, in such a way that the label is incorporated into the finally prepared labelled compound of formula (I). Said labelled materials are either commercially available or can be prepared by using commercially available labelling agents.

An examples of commercially available labelling agents, which can be used in the preparation of the labelled compounds of the present invention is [¹¹C]0₂, ¹⁸F , and Nal with different isotopes of Iodine.

In particular [C¹¹]0₂ may be converted to a [¹¹C]-methylating agent, such as [¹¹C]H₃I or [¹¹C]-methyl triflate.

Labelled compounds containing e.g. [¹²⁵l ] labelled 1-iodoprop-1-en-3-yl as substituent on N-8 may be prepared as described in the art [Elmaleh, et al.; J. Nucl. Med. 1996 37 1197-1202] .

Labelled compounds containing e.g. [¹⁸F] -alkyl substituted N-8 may be prepared as described in the art, e.g. in WO 96/39198.

Furthermore, labelled compounds of the present invention can, for example, be prepared by using labelled compounds R X in the reaction shown in scheme (1) above, wherein R⁴ and X are as defined above, except that R⁴ contains a label. These compounds can be prepared by known methods. Illustrative examples of labelled compounds R⁴X are those, wherein R⁴ is selected from [¹¹C]H₃-substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹¹C]F₃-substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹¹C]N-substituted phenyl, benzyl, heteroaryl and naphthyl groups, H₃[¹¹C]0-substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹⁸F]- substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹⁸F]₃C-substituted phenyl, benzyl, heteroaryl and naphthyl groups, H₃C[¹⁵0]-substituted phenyl, benzyl, heteroaryl and naphthyl groups, a 3,4-methylenedioxyphenyl group containing at least one [¹⁵0], N[¹⁵0]₂-substituted phenyl, benzyl, heteroaryl and naphthyl groups, C[¹³N]- substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹³N]amino-substituted phenyl, benzyl, heteroaryl and naphthyl groups, [¹²³l], [¹²⁵l] or [¹³¹l]-substituted phenyl, benzyl, heteroaryl and naphthyl groups and substituted or unsubstituted phenyl, benzyl, heteroaryl and naphthyl groups containing at least one [³H] attached to the ring or contained in a substituted group.

As described above, an unlabeiled compound of formula (I) can be converted to a labelled compound of formula (I) by using a labelling agent. A labelled compound according to the present invention containing a

[¹¹C]H₃-group can, for example, be prepared by reacting a free amine compound of formula (I), i.e. wherein R is H and R⁴ is as defined above, with a [¹¹C]-methylating agent, preferably with [¹¹C]H₃I or [¹¹C]-methyl triflate, or another suitable leaving group as exemplified below. In analogy, other [¹¹C] labelled groups R can be introduced, e.g. by reacting said free amine compound of formula (I) with a [¹¹C] labelled alkylating agent optionally derivatised with a suitable leaving group (LG), such as [¹¹C]-cyclohexyl triflate or any other cycloalkyl alkylating agent. Other types of labelling of compounds of formula (I) includes e.g. R representing alkyl substituted with [¹²⁵l]; alkenyl substituted with [¹²⁵l]; e.g. 1-[¹²⁵l]-prop-1-en-3-yl as described in the art, 1-[¹²⁵l]-but-1- en-3-yl; and alkynyl substituted with [¹²⁵l] or alkyl substituted with [¹⁸F], alkenyl substituted with [¹⁸F], alkynyl substituted with [¹⁸F]; Standard leaving groups for use in these types of reaction are known in the art and a few examples are mentioned below. Optionally the reaction may proceed through intermediate compounds such as the trialkyl tin derivatives, which is displaced by addition of Na[¹²⁵l] or [¹⁸F].

In analogy, other labelled groups can be introduced to the R group e.g. by derivatising said free amine compound of formula (I), to contain a suitable leaving group, attached to a alkyl chain of suitable length. The leaving group can then be displaced by a labelled nucleofile. The leaving group being e.g. esters of sulphuric and sulfonic acids in general such as mesylate, tosylate, brosylate, nosylate, triflate, nonaflates, tresylates; Esters of nitrous acid, and inorganic ester leaving groups such as ROPO(OH)₂, ROB(OH)₂ halogen, conjugate acid of alcohol, ether, quarternary amines, tertiary sulphides, trialkyl tin derivatives etc., all known in the art; Performing the reaction in a suitable solvent, preferable polar, aprotic solvent and preferably essential free of water, with a labelled agent, acting as a nucleofile. Such nucleofile, as e.g. [¹⁸F] , may require auxiliary reagents to dissolve in the solvent. An auxiliary agent of the form M⁺X^" , M⁺ being e.g. 4,7,13,16,21 ,24-hexaoxa-1 , 10- diazabicyclo [8.8.8] hexacosane, alkali metal ions, tetraalkyammonium etc. as described in the art, and X^" being e.g. carbonate, bicarbonate, hydroxide, formate or another counter ion, capable of dissolving radionuclides. Such compounds are known in the art.

As yet another embodiment of the invention, the compounds of formula(l) can represent substituents capable of co-ordinating to a metal complex. Such a metal could be positron emitting isotopes of Tc whereby the complete complex formation is radiolabelled and suitable for diagnostic use [Meegall S, et al.; Bioconiuαate Chem. 1996 7 421-429]. Such substituents are e.g. alkylthio, alkenylthio, and alkynylthio.

The preparation of the labelled compounds according to the present invention is further illustrated by the working examples described below (Preparative Examples 1-4).

Pharmaceutical Compositions

The present invention further provides a pharmaceutical composition comprising a diagnostically effective amount of the labelled compound of formula (I) or mixtures thereof together with at least one pharmaceutically acceptable carrier or diluent, wherein the labelled compound of formula (I) is defined as disclosed above. The carrier or diluent must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof and is not specifically limited.

Pharmaceutical formulations include those suitable for parenteral administration, including intramuscular, sub-cutaneous and intravenous administration. Intravenous injection is the preferred way of administration.

Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water-propylene glycol solutions. For example, parenteral injection liquid preparations can be formulated as solutions in aqueous polyethylene glycol solution. The labelled compounds of the present invention may thus be formulated for parenteral administration (e.g. by injection) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use. Aqueous solutions suitable for oral use can be prepared by dissolving the labelled compound of the present invention in water and adding suitable colorants, flavours, stabilising and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing the finely divided labelled compound of the present invention in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, or other well known suspending agents.

Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. In addition to the labelled compound of the present invention, these preparations may, for example, contain colorants, flavours, stabilisers, buffers, artificial and natural sweeteners, dispersants, thickeners, and/or solubilizing agents.

Alternatively, the active ingredients may be provided in the form of a dry powder, for example a powder mix of the labelled compound of the present invention in a suitable powder base, such as lactose, starch, starch derivatives such as hydroxyp ropy I methyl cellulose and polyvinylpyrrolidone (PVP). The powder composition may be presented in unit dose form for example in capsules or cartridges of, e.g., gelatine or blister packs.

Preferred compositions are tablets or capsules for oral administration and liquids for intravenous administration.

Suitable dosage ranges are in the range of from about 0.1 ng to about 100 γg of the labelled compounds of the present invention, administered in an appropriate dose, dependent as usual upon the exact mode and form of administration, the type of diagnosis, the subject involved and the body weight of the subject involved, and further the preference and experience of the physician or veterinarian in charge.

Diagnostic Methods and Method for in vivo Receptor Imaging (Neuroimaging).

The second object of the present invention is attained in a first embodiment of the invention by a method for determining the level of monoamine neurotransmitter re-uptake sites in a blood sample, said method comprising the steps of

(a) adding a compound of formula (I) or any of its enantiomers or a mixture thereof, or a pharmaceutically acceptable salt thereof in labelled or unlabeiled form to a blood sample;

(b) measuring an amount of a compound of formula (I) bound to a predetermined part of the blood sample; and

(c) calculating the number of the monoamine neurotransmitter re-uptake sites in blood platelets from the data obtained in (b).

In the following, this method is also referred to as the "in-vitro method" of the present invention.

The in-vitro method especially allows to accurately calculate the serotonine re-uptake sites in a cellular fraction obtained in step (b). The predetermined part of the blood sample is preferably a blood fraction that contains the blood platelets.

In step (2) of the in-vitro method of the present invention a labelled or unlabeiled compound of formula (I) or any of its enantiomers or a mixture thereof, or a pharmaceutically acceptable salt thereof is added to a blood sample. Generally, the compound of formula (I) added in step (a) is selected depending on the method of measuring the amount of the compound of formula (I) bound to said predetermined part of the blood sample used in step (b) of the in-vitro method of the invention.

In case a compound of formula (I) used in step (a) of the above mentioned method is a labelled compound of the present invention, this compound is preferably labelled with at least one radionuclide. Preferred radionuclides are those described above. In formula (I), R and R⁴ are as defined above, and preferred groups R and R⁴ are as defined above. Additionally, R⁴ being a fluorescent group is preferred. In step (a) of the in-vitro method of the present invention the compound of formula (I) may also be used in unlabeiled form. In this case, R and R⁴ are as defined above, and preferred groups R and R⁴ are as defined above. Additionally, R⁴ being a fluorescent group is preferred. The labelled or unlabeiled compound of formula (I) added in step (a) of the in vitro-method of the present invention can be detected by a suitable spectroscopic method, in particular UV spectroscopy and/or fluorescence spectroscopy.

In step (c) of the in-vitro method of the present invention, the level of the monoamine neurotransmitter re-uptake sites can be calculated from the data obtained in step (b) by using, for example, Scatchard Plot Analysis.

In a second embodiment, the second object of the present invention is solved by a method for the non-invasive determination of the distribution of a tracer compound inside a whole, intact living animal or human body using a physical detection method, wherein the tracer compound is a compound of formula (I) or any of its enantiomers and any mixture thereof, or a pharmaceutically acceptable salt thereof in its labelled or unlabeiled form.

In the following, this method is also referred to as "in-vivo method" of the present invention.

The physical method for detecting said tracer compound of formula (I) in the in-vivo method of the present invention is preferably selected from Position

Emission Tomography (PET), Single Photon Imaging Computed Tomography

(SPECT), Magnetic Resonance Spectroscopy (MRS), Magnetic Resonance Imaging

(MRI), and Computed Axial X-ray Tomography (CAT), or combinations thereof.

The tracer compound of formula (I) can be selected in accordance with the detection method chosen. The compound of formula (I) as described above can be used in labelled form or in unlabeiled form.

In case a labelled compound of formula (I) is used in the in-vivo method of the present invention, it is preferably labelled with a radionuclide, which is preferably selected from ¹¹C, ¹⁸F, ¹⁵0, ¹³N, ²³l, ¹²⁵l, ¹³¹l and ³H. Preferred examples of the labelled compound of formula (I) according to the present invention are given above.

The following table summarises preferred detection methods and the use of suitable radionuclides.

In case an unlabeiled compound of formula (I) is used in the in-vivo method of the present invention, said compound preferably contains at least one ¹⁹F containing substituent. Especially preferred unlabeiled compounds of formula (I) are those, wherein R⁴ is a phenyl group containing at least one substituent selected from

F, CF₃.

Specific examples of unlabeiled compounds of formula (I) which can be used in the in-vivo method of the present invention are

(±)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (±)-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene;

(±)-3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-chlorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-phenyl-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-phenyl-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-methylphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene;

(±)-3-(4-methylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (±)-3-(4-methoxyphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (±)-3-(4-trifluoromethylphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (±)-3-(4-trifluoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene;

(±)-3-(4-f luorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; or (±)-3-(4-fluorophenyl)-8-azabicyclo[3.2.1]oct-2-ene or a pharmaceutically acceptable salt thereof.

Examples of physical detection methods which can be used for detecting unlabeled compounds of formula (I) are HPLC and Mass spectroscopy.

The compound of formula (I) or any of its enantiomers or any mixtures thereof in labelled or unlabeiled form can be used as a diagnostic agent for the diagnosis of a disorder or disease of a living animal body, including a human, which disorder or disease is responsive to the inhibition of monoamine neurotransmitter reuptake in the central nervous system. Especially preferred is the use of these compounds for the diagnosis of a disorder or disease which is responsive to the inhibition of serotonine neurotransmitter re-uptake. Furthermore, said labelled or unlabeiled compound of formula (I) can be used for diagnosing a disorder or disease which is depression or a related disorder, such as pseudodementia or Ganser's syndrome, obsessive compulsive disorder, panic disorder, memory deficit, attention deficit hyperactivity disorder (ADHD syndrome), obesity, anxiety and eating disorder. Before conducting the in-vivo method of the present invention, a diagnostically effective amount of a labelled or unlabeiled compound of formula (I) is administered to a living body, including a human. Although the labelled or unlabeiled compound of formula (I) can be administered as such, it is preferably administered in the form of a pharmaceutical composition.

In case a labelled compound of formula (I) is administered in the form of a pharmaceutical composition , the pharmaceutical composition of the present invention as described above can be used.

In case an unlabeiled compound of formula (I) is administered in the form of a pharmaceutical composition, a pharmaceutical composition may be used, which differs from the above described pharmaceutical composition of the present invention in that it contains an unlabeiled compound of formula (I) instead of the labelled compound of formula (I).

The diagnostically effective amount of the labelled or unlabeiled compound of formula (I) to be administered before conducting the in-vivo method for the present invention is within a range of from 0.1 ng to 100 μg per kg body weight, preferably within a range of from 1 ng to 10 μg per kg body weight.

By using the in-vivo method of the present invention the distribution of said labelled or unlabeiled compound of formula (I) can be determined by a physical method in the body or any desired part thereof. Preferably, the distribution in a part of the nervous system, especially preferred in the brain, is determined. From the data obtained from the in-vivo method of the present invention, the extent of disease can be evaluated e.g. by a physician, preferably a neurologist. Said evaluation can especially be effected by comparing the data obtained from the in-vivo method of the present invention with control data. Said control data may, for example, be obtained from a control group of individuals. This group consists either of healthy individuals or of individuals who suffer from one of the above mentioned disorders or diseases.

Thus, the present invention further provides a method of diagnosis of a disorder or disease of a living human or animal body, which disorder or disease is responsive to the inhibition or monoamine neurotransmitter re-uptake, comprising the steps of (a) administering to said body a diagnostically effective amount of a compound of formula (I) in its labelled or unlabeiled form,

(b) detecting said compound and determining the distribution thereon in at least a part of said body by physical methods, and

(c) comparing the obtained data with control data. The pharmaceutical composition, which is preferably used in the in-vitro method of the present invention, can be provided in the form of an assay kit system wherein said pharmaceutical composition comprises either a labelled or unlabeiled compound of formula (I) in unit-dosage form in a suitable container. Preferably, said unit dosage is adjusted to be sufficient for analysing one blood sample according to the in-vitro method of the invention. Furthermore, said assay kit of the present invention can further comprise a stabilising composition. The stabilising composition can be selected from antioxidants, such as ascorbic acid, or from buffers of weak acid- base composition e.g. phosphate buffers or from various types of cyclodextrins e.g. hydroxypropyl β-cyclodextrin. The compounds and their derivatives of this invention are the first substances known that specifically bind to serotonine transporters. This allows for the first time to reliably determine the number of serotonine binding sites and related Kd values and the release of serotonine as well as the detection of changes in the serotonine metabolism in response to therapeutic drugs. Furthermore, a labelled compound of formula (I) may also be used in the analysis and adjustment of the treatment of patients having a lower level of serotonine re-uptake as compared to the normal level with serotonine uptake inhibitors. In this context, the compounds of the invention can be employed to assess whether the dosage of serotonine re-uptake inhibitors given is sufficient to occupy a high number of the serotonine transporter sites thereby blocking the re-uptake of serotonine and extending their presence and action within the synaptic cleft. The labelled compound of the invention can likewise be used to investigate whether an unnecessary high dose is given thereby blocking too many serotonine transporter sites and/or increasing the risk of unwanted side-effects. If a compound is given in a sufficient dose whereby maximal blocking of serotonine re-uptake is achieved, then higher doses will only increase the risk of side effects.

Fig. 1 is a characteristic PET scan showing the unique and very specific uptake and labelling of serotonine nerve terminals (containing the serotonine reuptake transporter) by Compound (3-4).

EXAMPLES

The invention is further illustrated with reference to the following examples which are not intended to be in any way limiting to the scope of the invention as claimed.

Example 1

Preparation Example

[Preparation of several intermediate compounds]

Method A:

3-(3,4-Dichlorophenyl)-8-methy l-8-azabicyclo[3.2.1 ]octan-3-ol (Compound 1 -1 ) A stirred solution of 1-bromo-3,4-dichlorobenzene (178.6 g, 0.8 mol) in anhydrous diethyl ether (1430 ml) under argon atmosphere was cooled to -70°C. A solution of n-butyl-lithium in hexane (310 ml 2.5 M; 0.78 mol) was added slowly while the temperature was kept below -65°C (addition time = 1 hour). The resulting solution was stirred for another 30 minutes at -70°C followed by addition of a solution of 8- methyl-8-azabicyclo[3.2.1]octan-3-one (50 g, 0.36 mol) in anhydrous tetrahydrofuran (360 ml). The temperature was kept below -50°C during the addition which took approximately one hour. The resulting solution was stirred at -50°C for two hours followed by addition of water (215 ml) over 15 minutes and 4 M HCI (360 ml) over 25 minutes. The temperature reached -20°C by the end of the addition. The organic phase was discharged and the aqueous phase was washed once with diethyl ether (500 ml). Concentrated NH₄OH (approximately 200 ml) was added to the aqueous phase until a pH of 10 was reached which resulted in precipitation of the title compound. The crude product was isolated by filtration which was suspended twice in water (2x300 ml) and finally dried under a lamp yielding the title compound as a white solid (88 g, 86%), m.p. 179.3-180.5° C. The following compounds were prepared analogously:

3-(4-Chloropheny l)-8-methyl-8-azabicyclo[3.2.1 |octan-3-ol (Compound 2-1 )

The title compound was prepared from 4-bromochlorobenzene (15.4 g, 81 mmol), n-butyllithium in hexane (31 ml 2.5 M; 78 mmol) and 8-methyl-8- azabicyclo[3.2.1]-octan-3-one (5 g, 36 mmol). Yield 5.7 g (63%) as a white solid, m.p. 186.3-187°C.

8-Methyl-3-(4-trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]octan-3-ol (Compound 3-

1) The title compound was prepared from 4-bromobenzotrifluoride, n- butyllithium in hexane (31.2 ml, 2.5M; 77.9 mmol) and 8-methyl-8- azabicyclo[3.2.1]octan-3-one (5 g, 36 mmol). Yield 6.2 g (60%) as a yellow solid, m.p. 189.2-190.5°C.

3-(4-Fluorophenyl)-8-methyl-8-azabicyclo[3.2.1]octan-3-ol (Compound 4-1)

The title compound was prepared from 4-bromofluorobenzene (26.3 g, 0.15 mol), n-butyllithium in hexane (60 ml, 2.5 M; 0.15 mol) and 8-methyl-8-azabicyclo- [3.2.1]octan-3-one (10 g, 71.7 mmol). Yield 9.9 g (59%), m.p. 168.5-170°C.

8-Methyl-3-phenyl-8-azabicyclo[3.2.1]octan-3-ol (Compound 5-1) The title compound was prepared from bromobenzene (42.1 mL, 0.4 mol), n-butyllithium in hexanes (156 mL, 2.5 M, 0.39 mol) and 8-methyl-8-azabicyclo[3.2.1]- octan-3-one (25 g, 0.18 mol). Yield 14 g (36%), m.p. 157-159°C.

8-Methyl-3-(4-methylphenyl)-8-azabicyclo[3.2.1]octan-3-ol (Compound 6-1)

The title compound was prepared from 4-bromotoluene (13.9 g, 81.4 mmol), n-butyllithium in hexanes (31.2 mL, 2.5 M; 78 mmol) and 8-methyl-8-azabicyclo[3.2.1]- octan-3-one (5 g, 35.9 mmol) in anhydrous tetrahydrofuran (40 mL). Yield 3.5 g (42%) as a white solid, m.p. 247-249°C.

3-(4-Methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]octan-3-ol (Compound 7-1)

The title compound was prepared from 4-bromoanisole (15.1 g, 80.5 mmol), n-butyllithium in hexanes (31.2 mL, 2.5 M; 77.9 mmol) and 8-methyl-8-azabicyclo- [3.2.1]octan-3-one (5 g, 36 mmol) in anhydrous tetrahydrofuran (40 mL). Yield 2.1 g (24%), m.p. 161.8-162.3°C.

Example 2

Preparation Example

[Preparation of unlabeiled compounds of formula (I)] Method A:

(±)-3-(3,4-Dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene (Compound 1-2)

Concentrated hydrochloric acid (50 ml) was added to a stirred solution of 3-

(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]octan-3-ol (Compound 1-1) (50 g,

0.17 mol) in glacial acetic acid (160 ml) at room temperature. The reaction mixture was heated at reflux. The starting material was consumed after 20 minutes and the reaction mixture was poured into approximately 1.5 I of crushed ice. Concentrated NH₄OH (approximately 325 ml) was added to the resulting aqueous solution until a pH of 10 was reached, resulting in precipitation of a sticky solid. The mixture was decanted and the reminiscence was triturated in water (1.5 I), resulting in a crystalline crude product. The crude product was washed a last time with water (300 ml) and was dried in a fume hood yielding the title compound as an off-white solid, m.p. 44-52°C. The following compounds were prepared analogously:

(±)-3-(4-Chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 2-2) The title compound was prepared from 3-(4-chlorophenyl)-8-methyl-8- azabicyclo[3.2.1]octan-3-ol (Compound 2-1) (4 g, 16 mmol), glacial acetic acid (15 ml) and concentrated hydrochloric acid (15 ml) yield of free base (3.6 g, 97%). Some of the free base (1.44 g, 6 mmol) was dissolved in ethanol (96%) and malonic acid (0.62 g, 6 mmol) in ethanol (96%) was added. The resulting solution was concentrated to an oil and the oil was trituated in diethyl ether. The title compound precipitated as a powder and was finally isolated by filtration. Yield (1.4 g, 71%) as white crystals m.p. 100.8-102.1°C.

(±)-8-Methyl-3-(4-trifluoromethylphenyl)-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 3-2)

The title compound was prepared from 8-methyl-3-(4-trifluoromethylphenyl)- 8-azabicyclo[3.2.1]octan-3-ol (Compound 3-1) (5 g, 17.5 mmol), glacial acetic acid (16 ml) and concentrated hydrochloric acid (16 ml). The free base of the title compound was dissolved in ethanol (96%) and malonic acid (1.17 g, 11.2 mmol) in ethanol (96%) was added. The solution was concentrated to dryness, and the residue was trituated in diethyl ether. The title compound precipitated as a powder and was finally isolated by filtration. Yield 3.9 g (60%), m.p. 106.7-107.8°C.

(±)-3-(4-Fluorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 4-2)

The title compound was prepared from 3-(4-fluorophenyl)-8-methyl-8- azabicyclo[3.2.1]octan-3-ol (Compound 4-1) (4.7 g, 20 mmol), glacial acetic acid (20 ml) and concentrated hydrochloric acid (20 ml). The free base of the title compound was dissolved in isopropanol and malonic acid (1.7 g, 16.3 mmol) was added. After a while the title compound precipitated as a powder and was finally isolated by filtration. Yield 4.6 g (72%), m.p. 122.2-123°C. (±)-8-Methyl-3-phenyl-8-azabicyclo[3.2.1 ]oct-2-ene malonate(Compound 5-2)

The title compound was prepared from 8-methyl-3-phenyl-8- azabicyclo[3.2.1]octan-3-ol (8 g, 37 mmol), glacial acetic acid (25 mL) and concentrated hydrochloric acid (8 mL). The free base of the title compound (7.4g, 37 mmol) was dissolved in absolute ethanol (20 mL) and added malonic acid (3.9g, 37.5 mmol), the solution was heated at reflux for a couple of minutes, some impurities was removed by filtration while the solution was still hot, the solution was cooled and kept at 5°C for at while, then seeded with a crystal and precipitation of the title compound began, after 2 hours at 5°C, the title compound was isolated by filtration, the crystals was washed with cold absolute ethanol (10 mL). Yield 5.9 g (53%), m.p. 131-131.8°C.

(±)-8-Methyl-3-(4-methylphenyl)-8-azabicyclo[3.2.1]oct-2-ene fumarate(Compound 6-2) The title compound was prepared from 8-methyl-3-(4-methylphenyI)-8- azabicyclo[3.2.1]octan-3-ol (3.4 g, 14.7 mmol), glacial acetic acid (11 mL) and concentrated hydrochloric acid (11 mL). The free base of the title compound was dissolved in diethyl ether and added fumaric acid (1.3 g, 11.2 mmol) in methanol. The resulting solution was concentrated to dryness, the residue was trituated in diethyl ether, the title compound precipitated as powder and was isolated by filtration. Yield 2.46 g (51%) m.p. 156.8-157.4°C.

(±)-3-(4-Methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene fumarate

(Compound 7-2) The title compound was prepared from 3-(4-methoxyphenyl)-8-methyl-8- azabicyclo[3.2.1]octan-3-ol (2g, 8 mmol), glacial acetic acid (6.4 mL) and concentrated hydrochloric acid (6.4 mL). The free base of the title compound was dissolved in ethanol (96%) and added fumaric acid (0.8 g, 6.9 mmol), no precipitate appeared, the solution was concentrated to dryness, the residue was crystallised from absolute ethanol. Yield 1.1 g (40%) as white crystals m.p.167.3-168.7°C. Example 3

Preparation Example

[Preparation of unlabeiled compounds of formula (I)]

(±)-3-(3,4-Dichlorophenyl)-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 1-3) To a stirred solution of (±)-3-(3,4-dichlorophenyl)-8-methyl-8- azabicyclo[3.2.1 ]oct-2-ene (Compound 1-2) (10 g, 37 mmol) in anhydrous 1 ,2- dichloroethane (100 ml) under nitrogen atmosphere 1-chloroethyl chloroformate (8 ml, 10.6 g, 74 mmol) was added. The reaction mixture was heated at reflux overnight, 1- chloroethyl chloroformate (4 ml, 5.3 g, 37 mmol) was added and the mixture was heated at reflux for 4 hours. The reaction mixture was concentrated to dryness. The residue was dissolved in methanol, and the reaction mixture was heated at reflux for 2 hours and then concentrated to dryness. The residue was chromatographed over silica gel (eluted with dichloromethane/methanol (9/1 , v/v) then dichloromethane/acetone/methanol (4/1/1 , v/v) and at last with methanol). The product fractions were concentrated to dryness, the residue (1.8 g; the rest was starting compound) was dissolved in glacial acetic acid (10 ml) and water (5 ml) and zinc powder (1 g, 15.2 mmol) were added. The reaction mixture was stirred overnight at room temperature. The reaction mixture was poured into water, and concentrated NH₄OH was added until pH=10, the water phase was extracted with diethyl ether, the organic phase was washed with water, dried with magnesium sulphate and evaporated to an oil. The oil crystallised upon standing at room temperature. The solid was dissolved in ethanol (96%) and 4 M sodium hydroxide (5 ml) was added and the reaction mixture was heated at reflux overnight. Then more 4 M sodium hydroxide (10 ml) was added and once again the reaction mixture was heated at reflux overnight. Then more 4 M sodium hydroxide (10 ml) was added and the reaction mixture was heated at reflux for 4 hours. The reaction mixture was concentrated until no more ethanol was left. During concentration water was added to maintain the volume of the solution approximately constant. The resulting solution was extracted with diethyl ether. The organic phase was dried with magnesium sulphate and evaporated to a brown oil. The oil was flash chromatographed over silica gel (50 g) (dichloromethane/acetone/methanol 4/1/1 (v/v)). The product fractions were concentrated to an oil. The oil was dissolved in ethanol (96%) and malonic acid (0.3 g, 0.29 mmol) was added. The title compound precipitated from this solution and was isolated by filtration. Yield 0.65 g (5.5%) mp.110-112°C.

(+)-3-(4-Chlorophenyl)-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 2-3)

To a stirred solution of 3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct- 2-ene (Compound 2-2) (2 g, 8.5 mmol) in anhydrous 1 ,2-dichloroethane (20 ml) under nitrogen atmosphere 1-chloroethyl chloroformate (1.25 ml, 11.6 mmol) was added. The reaction mixture was heated at reflux overnight, then 1-chloroethyl chloroformate (1 ml, 9.3 mmol) was added and once again the reaction mixture was heated at reflux overnight. The reaction mixture was concentrated to an oil and the oil was dissolved in methanol (25 ml). This solution was heated at reflux for 2 hours and then concentrated to an oil. The residue was dissolved in water and concentrated NH₄OH was added until pH 10 was reached. The water phase was extracted with diethyl ether. The organic phase was dried with magnesium sulphate and concentrated to dryness. The residue was chromatographed over silica gel (dichloromethane/acetone/methanol, 4/1/1 (v/v)). The product fractions were concentrated to an oil, the oil was dissolved in ethanol (96%) and malonic acid (0.55 g, 5.3 mmol) in ethanol (96 %) was added. This solution was concentrated to an oil, the oil was trituated in diethyl ether. The title compound precipitated as a powder and was isolated by filtration. Yield (1.32 g, 48%), m.p. 136.1-138°C.

The following compound was prepared analogously:

(±)-3-(4-Trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene (Compound 3-3) M.p: 131.4 - 132.8

(±)-3-(4-Fluorophenyl)-8-azabicyclo[3.2.1]oct-2-ene malonate (Compound 4-3)

The title compound was prepared from (±)-3-(4-fluorophenyl)-8-methyl-8- azabicyclo[3.2.1]oct-2-ene (Compound 4-2) (1.6 g, 7.37 mmol) and 1-chloroethyl chloroformate (1.2 ml, 1.6g, 11 mmol). The free base of the title compound was dissolved in isopropanol and malonic acid (0.43g, 4.1 mmol) was added. The title compound precipitated from this solution and was isolated by filtration. Yield 1.14 g (50%) m.p. 132.2-132.6°C.

The following compounds can be prepared analogously: (±)-3-phenyl-8-azabicyclo[3.2.1]oct-2-ene (Compound 5-3)

(±)-3-(4-methylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene (Compound 6-3) (±)-3-(4-methoxyphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene (Compound 7-3)

Example 4

Preparation Example

[Preparation of labelled compounds of formula (I)]

Preparation of [¹¹C] Methyl Iodide:

[¹¹C] Carbon dioxide was prepared by the 14N(p,a)¹¹C nuclear reaction using a nitrogen gas target and 16 MeV protons produced by a GE Medical Systems PETtrace cyclotron.

[¹¹C] Carbon dioxide was purged from the target in a stream of nitrogen gas and trapped on 4 A molecular sieves. On heating, the [¹¹C] 0₂ was released and passed through a solution of LiAIH₄ in anhydrous tetrahydrofuran (THF; 300 μl). On completion of [¹¹C] 0₂ transfer, the THF was evaporated and 1 ml hydroiodic acid was added. On heating at 160° C the [¹¹C] methyl iodide formed was distilled in a stream of nitrogen gas to a reaction vial containing the labelling precursor.

Synthesis and purification of [¹¹C] labelled (±)8-methyl-3-(4- trifluoromethylphenyl)-8-azabicyclo[3.2.1]oct-2-ene (Compound 3-4)

(±)-3-(4-trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene (Compound 3- 3) in the form of a free amine (1 mg) was dissolved in anhydrous dimethyl sulphoxide (DMSO; 300 μl), and then reacted with [¹¹C]-methyl iodide and heated for 5 min at 130°C. The resulting N-[¹¹C]-methyl labelled [¹¹C]-compound was subsequently purified by HPLC. Removal of the HPLC solvent was achieved by heating the [¹¹C] - labelled (±)8-methyl-3-(4-trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene containing fraction under reduced pressure. The labelled product was then formulated in saline or water (10 ml) and passed over a 0.22 μm membrane filter into a sterile vial.

Synthesis and purification of [¹¹C] labelled (±)-(3,4-dichlorophenyl)-8-methyl-8- azabicyclo [3.2.1 ]oct-2-ene (Compound 1-4)

(±)-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene malonate

(Compound 1-3) was dissolved in DMSO (300μl) and 0.5 mg NaOH were added thereto. The resulting mixture was then reacted with [¹¹C]-methyliodide under heating for 5 min at 130°C. The purification was conducted in analogy to the purification of

Compound 3-4 above.

The following compounds were prepared and purified analogously.

[¹¹CJ labelled (±)-3-(4-chlorophenyl)-8-methyl-8-azabicyclo [3.2.1 ]oct-2-ene (Compound 2-4)

The title compound was prepared from (±)-3-(4-chlorophenyl)-8- azabicyclo[3.2.1]oct-2-ene malonate (Compound 2-3), NaOH and [¹¹C]methyliodide in DMSO and purified as disclosed for Compound 1-4.

[¹¹C] labelled (±) -3-(4-fluorophenyl)-8-methyl-8-azabicyclo [3.2.1] oct-2-ene (Compound 4-4)

The title compound was prepared from (±)-3-(4-fluorophenyl)-8- azabicyclo[3.2.1 ] oct-2-ene malonate (Compound 4-3), NaOH and [¹¹C]methyliodide in DMSO and purified as disclosed for Compound 1-4. Likewise the following compounds can be prepared:

[¹¹C] labelled (±)-3-phenyl-8-methyl-8-azabicyclo[3.2.1]oct-2-ene (Compound 5-4) [¹¹C] labelled (±)-3-(4-methylphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene (Compound 6-4) [¹¹C] labelled (±)-3-(4-methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene (Compound 7-4) The labelled products were synthesised in less than 30 minutes. The following characteristics were determined for Compounds 1-4, 2-4, 3-4 and 4-4: Radiochemical purity: > 98 %.

Typical mass of compounds 1-4, 2-4, 3-4 and 4-4 in the final product: 30-60 nmol in a 10 ml formulation.

Typical radioactivity of final product: 1-4 GBq. Typical specific activity: 30 - 100 GBq/μmol.

Example 5 In vivo administration of [¹¹C] labelled (±)-3-(4-trifluoromethylphenyl)-8-methyl-8- azabicyclo[3.2.1]oct-2-ene (Compound 3-4)

Compound (3-4) was used as a marker for the number of serotonine transporter sites. The binding of labelled compound (3-4) to the serotonine transporter sites was measured as follows.

Experimental Animals

As test animals three female pigs (Hampshire x Yorkshire x Duroc x Landrace crossbred) weighing 39 to 44 kg were used. They were housed singularly in a thermostatically controlled (20°C) animal colony with natural lighting conditions. The pigs had free access to water but were deprived of food for 24 hours prior to experiments.

Pigs were sedated with an i.m. injection of Midazolam (0.5 mg/kg) and Ketamine HCI (10 mg/kg). After 10 to 15 minutes a catheter was installed in an ear vein through which a mixture of Midazolam (0.25 mg/kg) and Ketamine (5 mg/kg) was administered. The pigs were then incubated and anaesthetised with Isoflourane in 0₂/N₂0. Catheters (Avanti® size 4F-7F) were surgically installed in a femoral artery and vein. Infusions of isotonic saline (ca. 100 cm⁵/h) and 5% of glucose (ca. 20 cm³/h) were administered i.v. throughout the experiments. Body temperature was thermostatically maintained in the normal range (39.0-39.4°C) and physiological functions (i.e. blood pressure, heart rate and expired air C0₂) were monitored continuously. Hematocrit and whole blood acid-base parameters (i.e. pH, pC0₂, p0₂, HC0₃ and 0₂ saturation) were measured and disturbances in body fluid balance were corrected by appropriate procedures (e.g. force ventilation and/or changes in infusion rates).

PET Neuroimaαinα

The pigs were studied in the supine position in the scanner (Siemens ECAT

EXACT HR) using a custom-made head-holding device. The regional distribution and binding of Compound (3-4) in pig brain was studied by administering an i.v. dose of ca. 10μg followed immediately by an i.v. injection of heparin solution to flush the catheter. Scanning began on injection of Compound (3-4) and consisted of 28 frames

(6 x 10 seconds, 4 x 30 seconds, 7 x 1 minute, 5 x 2 minutes, and 5 x 10 minutes).

Under control conditions, no further injections were given during the scanning period.

Under conditions of antidepressant treatment, an intravenous dose of 5 mg/kg was administered at 20 minutes after injection of Compound (3-4) in order to determine whether the antidepressant drug influenced the cerebral binding, kinetics and distribution of the tracer compound.

Fig. 1 shows a coronal (left), transaxial (centre) and sagittal (right) section of a pig brain labelled with Compound (3-4). Accumulation of the compound can be seen in the serotonergic Raphe nuclei and the thalamus.

Blood Sampling

A sequence of twenty-eight arterial blood samples (1-2 ml) were drawn from the pigs for determination of total plasma radioactivity concentration of Compound (3-

4) at the following times: 18 x 10 seconds, 4 x 30 seconds, 5 x 1 minute, 7 x 5 minutes, and 1 x 15 minutes). Total plasma radioactivity was measured and metabolite correction was carried out using 200 μl plasma from the samples drawn at 0.5, 2, 10,

30 and 60 minutes (200 μl plasma alkalinised with 10 μl 50% NaOH and to which 400 μl ethyl acetate was added).

200 μl of the organic layer was removed and the quantity of ¹¹C radioactivity was determined. Plasma levels of un-metabolised Compound (3-4) per cm³ plasma were obtained by decay correcting the ¹¹C count to start of scanning and multiplying by the dilution factor. Arterial samples obtained after infusion of Citalopram were used for HPLC estimation of the concentration of Citalopram in plasma.

Metabolite Analysis Acetonitrile (0.05 ml) was added to plasma samples for metabolite analysis.

After centrifugation, supernatant was loaded into a 1 ml injection loop and chromatographed using the analytical HPLC conditions stated above. The amount of uncharged Compound (3-4) was determined by integration of the radiopeak corresponding to Compound (3-4) in relation to the sum of all radioanalytes. Biexponential fitting of the data to the total plasma radioactivity concentration was performed to generate a metabolite-corrected input function. The rate of metabolism of Compound (3-4) was determined by multilinear curve-fitting based on the appearance of plasma metabolites from the metabolite-corrected plasma time-activity curve.

Pharmacokinetic Analysis

Seven brain regions of interest (ROIs) were identified using a neuroanatomical atlas of the pig brain [Yoshikawa T; Atlas of the brains of domestic animals: Pennsylvania State University Press, University Park, Penn., 1968]. For each region, radioactivity concentrations were calculated for the sequence of frames, were corrected for the radioactive decay of ¹ C (20.3 min), and were plotted versus time. The data for illustrations were expressed in terms of standard uptake values (SUV), i.e. [radioactivity in ROI (Bq/cc) X body weight (g)/injected dose of radioactivity (Bq)]. Normalisation of the data was carried out by dividing SUVs obtained at a particular time in the ROI by SUVs in the cerebellum, a region devoid of neuronal serotonine transporters. The cerebellum (CB) was also used as reference region for determination of binding potential. Binding potential (B.P.) was calculated as follows: B.P. = B_Roι/F = [AROI - ACB / A_CB) - 1] = {[(K

CB)] - 1 }. Estimations of pharmacokinetic parameters for a two-component model was carried out using custom-made software based on the word of Gjedde and Wong [Gjedde A <& Wong DF. Modelling neuroreceptor binding of radioligands in vivo. Quantitative imaging; Neuroreceptors. Neurotransmitters. and Enzymes: Frost JJ and Wagner, Jr. HN (Eds.), Raven Press, New York. 1991 51-79], Kι expresses the unidirectional clearance of the tracer from the circulation to the single tissue compartment, k₂ in the case of the cerebellum is the true rate constant for clearance from the brain, whereas k₂ is an apparent rate constant of clearance from the single tissue compartment, assuming that equilibration between tissue compartments of solution and of binding are so rapid that a single compartment results. The Kι/k₂ ratio is termed the apparent partition volume and expresses the binding of the compound in the ROI.

Example 6

In vitro diagnosis

Reuptake of Serotonine into platelets:

Platelet-rich plasma was obtained by centrifugation of blood samples at 200 x g for 10 min at 20° C. Platelet membranes were prepared by lysis and homogenisation of the platelet pellet following the method of Plenge and Mellerup

[Plenge P & Mellerup ET: [³H]Citalopram binding to brain and platelet membranes of human and rat; J. Neurochem. 1991 56 248-252].

Aliquots of 500 μl membrane suspension were added to 25 μl of [³H]-X, mixed and incubated for 60 min at 2°C. Non-specific binding was determined using Paroxetine (1 μM, final concentration). After incubation the samples were added 5 ml of ice-cold buffer and poured directly onto Whatman GF/C fibre filters under suction and immediately washed with 5 ml ice-cold buffer.

The amount of radioactivity on the filters were determined by conventional liquid scintillation counting. Five to six concentrations of [³H]-X were used in the incubation mixture to determine the density of binding sites (Bmax) by Scatchard analysis.

In an Eppendorf tube containing 25μl [¹⁴C] -5HT was added 375μl PRP

(platelet rich plasma) and incubated at 37°C for 12(±)1 min. Each sample was incubated in triplicate. Incubations were terminated by the addition of 400μl ice cold stopping solution (40mM EDTA in 100 mM NaCI) and an aliquot of 200μl was removed and placed in a scintillation vial ready to be counted for radioactivity. The remaining incubation mixture was rapidly centrifuged at >1500x g for 2 min. After centrifugation a 200 μl aliquot of the supernatent was removed and added to scintillation vials. 10 ml scintillation fluid was added to each vial and counted for 5 min in a liquid scintillation counter. Triplicate determinations were made for each sample. The percentage uptake of [¹⁴C] -5HT for each sample was calculated from the mean of the triplicate counts.

Claims

A labelled compound derived from a compound represented by the general formula (I)

R

or any of its enantiomers or any mixture thereof, or a pharmaceutically acceptable salt thereof; wherein

R is hydrogen, alkyl, haloalkyl, thioalkyl, alkenyl, thioalkenyl, haloalkenyl, alkynyl, thioalkynyl, cycloalkyl, cycloalkylalkyl or 2-hydroxyethyl; and

R⁴ is

phenyl, which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl;

3,4-methylenedioxyphenyl;

benzyl, which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; heteroaryl, which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl;

naphthyl, which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl; or

a fluorescent group.

2. The labelled compound according to claim 1 , which contains at least one radionuclide.

3. The labelled compound according to claim 2, wherein the radionuclide is selected from ¹¹C, ¹⁸F, ¹⁵0, ¹³N, ¹²³l, ¹²⁵l, ¹³¹l , ³H and ^99mTc.

4. The labelled compound according to any of claims 1 to 3, wherein

R is an alkyl group having 1 to 6 C-atoms; and

R⁴ is a phenyl group which may be substituted one or more times with substituents selected from Cl, I, F, CF₃, CH₃ and OCH₃.

5. The labelled compound according to any of claims 1 to 4, which is (┬▒)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene;

(┬▒)-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-(4-chlorophenyl)-8-azabicyclo[3.2.1]oct-2-ene; (┬▒)-3-phenyl-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-phenyl-8-azabicyclo[3.2.1 ]oct-2-ene;

(┬▒)-3-(4-methylphenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-(4-methylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-(4-methoxyphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (┬▒)-3-(4-methoxyphenyl)-8-azabicyclo[3.2.1]oct-2-ene; (┬▒)-3-(4-trifluoromethylphenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-ene; (┬▒)-3-(4-trif luoromethylphenyl)-8-azabicyclo[3.2.1 ]oct-2-ene; (┬▒)-3-(4-f luorophenyl)-8-methyl-8-azabicyclo[3.2.1 ]oct-2-ene; or (┬▒)-3-(4-f luorophenyl)-8-azabicyclo[3.2.1 ]oct-2-ene;

labelled with at least one radionuclide selected from [¹¹C], [¹⁸F] and [¹³N];

or a pharmaceutically acceptable salt of said labelled compound.

6. A pharmaceutical composition comprising a diagnostically effective amount of a labelled compound according to any of claims 1 to 5, together with at least one pharmaceutically acceptable carrier or diluent.

7. A method for determining the level of monoamine neurotransmitter re-uptake sites in a blood sample, comprising the steps of

(a) adding a compound of formula (I) according to any of claims 1-5, or any of its enantiomers or any mixture thereof, or a pharmaceutically acceptable salt thereof, in labelled or unlabeiled form to a blood sample;

(b) measuring the amount of the compound of formula (I) bound to a predetermined part of the blood sample; and

(c) calculating the level of the monoamine neurotransmitter re-uptake sites from the data obtained in step (b).

8. The method of claim 7, wherein the level of the 5-HT re-uptake sites are calculated.

9. The method of claim 7 or 8, wherein the predetermined part of the blood sample used in step (b) are platelets.

5 10. The method of any of claims 7 to 9, wherein the compound of formula (I) added in step (a) is a labelled compound according to any of claims 2 to 5.

11. The method of any of claims 7 to 9, wherein the compound of formula (I) added in step (a) is a compound which is detectable by spectroscopy, in particular by

10 UV-spectroscopy and/or fluorescence spectroscopy.

12. The method of claim 11 , wherein the compound of formula (I) added in step (a) is in its unlabeiled form, wherein

15 R is an alkyl group having 1 to 6 C-atoms; and

R⁴ is a phenyl group which may be substituted one or more times with substituents selected from Cl, I, F, CF₃, CH₃ and OCH₃, or a fluorescent group.

20 13. A method for the non-invasive determination of the distribution of a tracer compound inside a whole, intact living animal or human body using a physical detection method, wherein the tracer compound is a compound of formula (I) according to any of the claims 1 to 5 or any of its enantiomers or any mixture thereof, or a pharmaceutically acceptable salt thereof, in labelled or unlabeiled

25 form.

14. The method of claim 13, wherein the physical detection method is selected from PET, SPECT; MRS, MRI, CAT, or combinations thereof .

30 15. The method of claim 13 or 14, wherein the compound of formula (I) is a labelled compound according to any of claims 2 to 5.

16. The method of claim 13 or 14, wherein the compound of formula (I) is in its unlabeiled form, wherein

5 R is an alkyl group having 1 to 6 C-atoms; and

10 17. Use of a compound of the formula (I) according to any of claims 1-5 or any of its enantiomers or any mixture thereof in labelled or unlabeiled form for the manufacture of a diagnostic agent for the diagnosis of a disorder or disease of a living animal body, including a human, which disorder or disease is responsive to the inhibition of monoamine neurotransmitter re-uptake in the central nervous

15 system.

18. The use according to claim 17, wherein the monoamine neurotransmitter is serotonine.

20 19. The use according to claim 17 or 18, wherein the disorder or disease is depression or a related disorder, such as pseudodementia or Ganser's syndrome, obsessive compulsive disorders, panic disorders, memory deficits, attention deficit, hyperactivity disorder, obesity, anxiety and eating disorders.

25 20. The use according to any of claims 17 to 19, wherein the compound of formula (I) is a labelled compound according to any of claims 2 to 5.

21. The use according to any of claims 17 to 19, wherein the compound of formula (I) is in its unlabeiled form, wherein

30

R is an alkyl group having 1 to 6 C-atoms; and R⁴ is a phenyl group which may be substituted one or more times with substituents selected from Cl, I, F, CF₃, CH₃ and OCH₃, or a fluorescent group.

22. A method of diagnosis of a disorder or disease of a living human or animal body, which disorder or disease is responsive to the inhibition of monoamine neurotransmitter re-uptake, comprising the steps of

(a ) administering to said body a diagnostically effective amount of a compound of formula (I) according to any of the claims 1 to 5 in its labelled or unlabeiled form,

(b) detecting said compound and determining the distribution thereof in at least a of said body by physical methods and

(c) comparing the obtained data with control data.

23. The method of claim 22, wherein the physical detection method is selected from PET, SPECT, MRS, MRI, CAT, or combinations thereof.

24. The method of claim 22, wherein said part of the body is the brain and/or another part of the nervous system.

25. The assay kit comprising the composition according to claim 6 in unit dosage form in a suitable container.

26. An assay kit according to claim 25 further comprising a stabilising composition.

27. An assay kit comprising a pharmaceutical composition comprising a diagnostically effective amount of an unlabeiled compound of formula (I) together with at least one pharmaceutically acceptable carrier or diluent, said assay kit further comprising a stabilising composition.