WO2009027294A1

WO2009027294A1 - Substituted azabicyclo [4.1.0] heptane compounds for use as monoamine reuptake inhibitors

Info

Publication number: WO2009027294A1
Application number: PCT/EP2008/060912
Authority: WO
Inventors: Silvia Terreni
Original assignee: Glaxo Group Limited
Priority date: 2007-08-24
Filing date: 2008-08-21
Publication date: 2009-03-05
Also published as: JP2010536918A; GB0716573D0; EP2182946A1

Abstract

The present invention relates to novel compounds of formula (I)', pharmaceutically acceptable salts, prodrugs or solvates thereof wherein R1 is hydrogen or C1-4 alkyl; R2 is an α or β naphthyl group, optionally substituted by 1 or 2 groups R8, each of them being the same or different; R8 is selected from a group consisting of: halogen, cyano, C1-4alkyl; R5 is hydrogen or C1-4 alkyl; R6 is hydrogen or C1-4 alkyl; R7 is selected in the group consisting of: hydrogen, fluorine, and C1-4 alkyl; or corresponds to X, X1, X2 or X3; wherein X corresponds to (I)'a X1 corresponds to (I)'b X2 corresponds to (I)'c X3 corresponds to (I)'d R3 is hydrogen or C1-4 alkyl; or corresponds to X or X1; R4 is hydrogen or C1-4 alkyl; or corresponds to X or X1; R9 is C1-4alkyl; R10 is hydrogen, C1-4alkyl, C3-6cycloalkyl or C3-6cycloalkylC1-3alkyl; R11 is haloC1-2alkyl; n is 1 or 2; processes for their preparation, intermediates used in these processes, pharmaceutical compositions containing them and their use in therapy, as serotonin (5-HT), dopamine (DA) and norepinephrine (NE), re-uptake inhibitors.

Description

SUBSTITUTED AZABICYCLO [4.1.0] HEPTANE COMPOUNDS FOR USE AS MONOAMINE REUPTAKE INHIBITORS

The present invention relates to novel compounds, processes for their preparation, intermediates used in these processes, pharmaceutical compositions containing them and their use in therapy, as serotonin (5-HT), dopamine (DA) and norepinephrine (NE), reuptake inhibitors.

Brain tissue is constituted of neuronal cells which are able to communicate with each other via specific cellular structures named synapses. The exchange of signals between neurons in the synapses happens through neurochemical messengers named neurotransmitters, acting on specific target protein molecules, both post and pre-synaptic, referred to as receptors. Monoamines represent a family of small neurotransmitter molecules sharing common chemical features, and include serotonin (5-HT), dopamine (DA) and norepinephrine (NE).

Monoamine neurotransmitters are released into the synaptic cleft between neurons and interact with receptors present on the membrane of the target cells. The switch of the neurochemical signal occurs mainly by removal of the neurotransmitter molecules through other protein molecules referred to as monoamine transporters (SERT for 5-HT, DAT for DA and NET for NE). Transporters are able to bind neurotransmitter molecules and move them into the presynaptic terminals, this cellular mechanism referred to as re-uptake. Pharmacological inhibition of the re-uptake process can cause an increase of monoamine at synaptic level and as a consequence an enhancement of the physiological activity of neurotransmitters.

Serotonergic neurotransmission in the brain is mediated by a large family of receptors comprising both the G-protein coupled receptors and ligand-gated ion channels including 14 subtypes, and is involved in a vast variety of physiologic functions. Compounds endowed of inhibitory properties at the SERT are predicted to have the ability to treat in mammals, including humans, a variety of disorders associated with this neural system, for example eating disorders, major depression and mood disorders, obsessive compulsive disorders, panic disorders, alcoholism, pain, memory deficits and anxiety. Included among these disorders are disorders related to depression, such as pseudodementia or Ganser's syndrome, migraine pain, bulimia, obesity, pre-menstrual syndrome or late luteal phase syndrome, tobacco abuse, panic disorder, post-traumatic syndrome, memory loss, dementia of ageing, acquired immunodeficiency syndrome dementia complex, memory dysfunction in ageing, social phobia, attention deficit hyperactivity disorder, chronic fatigue syndrome, premature ejaculation, erectile difficulty, anorexia nervosa, disorders of sleep, autism, mutism or trichotillomania.

Major depression is an affective disorder, or disorder of mood, characterized by several symptoms including feeling of profound sadness, worthlessness, despair and loss of interest in all pleasures (anhedonia), recurrent thoughts of death, mental slowing, loss of energy, an inability to take decision, often associated with anxiety and agitation. These symptoms are persistent and can range from mild to severe.

The pathophysiology of major depression is poorly understood being a multifactorial syndrome and, due to this, several neurotransmitter systems have been implicated. However, it is generally believed that the disorder stems from a decrease in the synaptic concentration of monoamine neurotransmitters, mainly NE and 5-HT, in critical brain areas, leading to the "monoamine theory" of depression.

Several lines of preclinical and clinical evidence indicate that an enhancement of serotonin-mediated neurotransmission might be effective in the treatment of major depression and actually the selective serotonin re-uptake inhibitors (SSRIs ) have come to dominate the therapy of depression over the last two decades. Fluoxetine, the first SSRI to be introduced, is the prototype of this group. Other members include Paroxetine, Sertraline, Fluvoxamine, Citalopram.

However, it is not clear exactly how these agents act to relieve depression. As with other classes of antidepressant, there is a lag of several weeks before the onset of the mood- elevating effect, despite the rapid blockade of the serotonin re-uptake. It is presumed that secondary adaptive changes must occur at serotonergic synapses after chronic administration of SSRIs i.e. down-regulation of release-regulating autoreceptors and increased neurotransmitter release. The delayed onset of anti-depressant effect is considered to be a serious drawback to currently used SSRIs. Moreover, although there is generally good tolerability of SSRIs, the elevation of 5-HT levels at central and peripheral synapses leads to stimulation of receptor subtypes like 5-HT_2C and 5-HT₃, which contributes to agitation and restless, along with gastrointestinal and sexual side-effects.

The success of the SSRIs rekindled interest in the development of selective norepinephrine re-uptake inhibitors (SNRIs) as potential antidepressants. A number of such compounds have been synthesized, e.g. Nisoxetine, Maprotiline, Tomoxetine and Reboxetine. Furthermore, many compounds, including old tricyclic antidepressants, have a mixed NET and SERT inhibition profile, like lmipramine and Amitriptyline (with SERT potency > NET) and Desipramine, Nortriptyline, and Protriptyline (NET potency > SERT).

The pharmacological manipulation of the DAT can in principle have the ability to elevate DA levels in the mesolimbic system, reversing the anhedonia that is a core symptom of major depression. A DAT inhibition component, in combination with a blockade of SERT and NET, can also have the ability to improve the lack of motivation and attention and enhance cognitive deficits seen in depressed patients. On the other hand, blockade of DAT has to be carefully managed in order to avoid potential reinforcing effects and abuse liability. However compounds with DAT inhibition in their pharmacology, such as Dexmethylphenidate, Methylphenidate and Bupropion, have been successfully marketed. Clinical studies indicate that patients with poor response to SSRIs benefit from combination therapy with agents that enhance dopaminergic tone. As a result, compounds with a strong SERT inhibiting activity combined with a well balanced NET blockade and moderate DAT inhibiting activity may therefore provide a replacement for current combination therapies for treating unresponsive patients, providing greater efficacy and therapeutic flexibility with a more rapid onset of anti-depressant effect.

Due to their valuable DAT inhibition, the compounds of the present invention are considered useful for the treatment of Parkinsonism, depression, obesity, narcolepsy, drug addiction or misuse, including cocaine abuse, attention-deficit hyperactivity disorders, Gilles de Ia Tourettes disease and senile dementia. Dopamine re-uptake inhibitors enhance indirectly via the dopamine neurones the release of acetylcholine and are therefore also useful for the treatment of memory deficits, e.g. in Alzheimers disease, presenile dementia, memory dysfunction in ageing, and chronic fatigue syndrome. Noradrenaline re-uptake inhibitors are considered useful for enhancing attention, alertness, arousal, vigilance and for treating depression.

The object of the present invention is to provide novel compounds which are serotonin (5- HT), dopamine (DA) and norepinephrine (NE), re-uptake inhibitors.

In a first aspect, the present invention provides a compound of formula (I) or a pharmaceutically acceptable salt, solvate or prodrug thereof:

wherein

Ri is hydrogen or Ci_-4 alkyl;

R₂ is an α or β naphthyl group, optionally substituted by 1 or 2 groups R₈, each of them being the same or different;

R₈ is selected from a group consisting of: halogen, cyano, C_1-4alkyl; R₅ is hydrogen or C_1-4 alkyl; R₆ is hydrogen or Ci_-4 alkyl;

R₇ is selected in the group consisting of: hydrogen, fluorine, and C_1-4 alkyl; or corresponds to X, Xi, X₂ or X₃; wherein

X corresponds to:

/V_n ⁰- ^"Ft ^vio Xi corresponds to:

/ 'V_n ⁰- ^"Ft ¹¹

X₂ corresponds to:

X₃ corresponds to:

R₃ is hydrogen or C_1-4 alkyl; or corresponds to X or X₁; R₄ is hydrogen or C_1-4 alkyl; or corresponds to X or X₁; R₉ is C_1-4alkyl; R₁₀ is hydrogen , C_1-4alkyl, C₃-₆cycloalkyl or C₃-₆cycloalkylC_1-3alkyl; R₁₁ is haloC_1-2alkyl; n is 1 or 2.

Because of the presence of the fused cyclopropane ring, compounds of formula (I) are believed to have a "cis" disposition of the substituents (both groups R₂ and R₇ linked to the bicyclic ring system are on the same face of this bicyclic ring system).

It will be appreciated that compounds of formula (I) possess at least two stereogenic centers, namely at position 1 and 6 in the 3-azabicyclo[4.1.0]heptane portion of the molecule. Thus, the compounds may exist in two stereoisomers which are enantiomers with respect to the stereogenic centers in the cyclopropane ring. It will also be appreciated, in common with most biologically active molecules that the level of biological activity may vary between the individual stereoisomers of a given molecule. It is intended that the scope of the invention includes all individual stereoisomers (diastereoisomers and enantiomers) and all mixtures thereof, including but not limited to racemic mixtures, which demonstrate appropriate biological activity with reference to the procedures described herein.

In one embodiment of the present invention compounds of formula (I)' are provided which correspond to the compounds of formula (I), or pharmaceutically acceptable salts, solvates or prodrugs thereof, having "cis" disposition, represented by the bold highlight of the two bonds near the cyclopropyl moiety:

wherein R₁, R₂, R3, R₄, R5, Re and R₇ are defined as above for compounds of formula (I).

From now on throughout the document, the symbol ' (prime) is used to identify compounds having "cis" disposition for the bonds bearing groups R₂ and R₇, represented by the bold highlight of the two bonds near the cyclopropyl moiety. In one embodiment of the present invention, the bold highlight of the two bonds near the cyclopropyl moiety bearing groups R₂ and R_7, indicate, mixtures (including but not limited to racemic mixtures) of those cis isomers.

In compounds of formula (I)' there are at least two stereogenic centers, which are located in the cyclopropane portion, as depicted below; through optical resolution of a mixture containing the two stereoisomers which are enantiomers with respect to the stereogenic centers at positions named 1 and 6, steroisomers of compounds of formula (I)' having a single absolute configuration at stereogenic centers named 1 and 6, may be obtained as shown in the scheme below:

Resolution

Absolute configuration of stereogenic centers at position named 1 and 6 may be assigned using Cahn-lngold-Prelog nomenclature based on groups' priorities.

In one embodiment of the present invention compounds of formula (IA) are provided that correspond to stereochemical isomers of compounds of formula (I)', having the configuration shown in the picture below at stereogenic centers at position named 1 and

wherein R₁, R₂, R3, R₄, Rs, Re and R₇ are defined as above for compounds of formula (I), or pharmaceutically acceptable salts, solvates or prodrugs thereof.

It is intended in the context of the present invention that stereochemical isomers of formula (IA) are enriched in one configuration at stereogenic centers named 1 and 6. In one embodiment, the isomers correspond in one embodiment to at least 90% e.e. (enantiomeric excess). In another embodiment the isomers correspond to at least 95% e.e. In another embodiment the isomers correspond to at least 99% e.e.

From now on throughout the document, the suffix "A" in brackets is used to identify stereochemical isomers of compounds of the invention having the configuration shown above for compounds of formula (IA) at stereogenic centers at positions named 1 and 6.

In another embodiment of the present invention compounds of formula (IB) are provided that correspond to stereochemical isomers of compounds of formula (I)', having the configuration shown in the picture below at stereogenic centers at position named 1 and 6:

wherein R₁, R₂, R3, R₄, R₅, Re and R₇ are defined as above for compounds of formula (I), or or pharmaceutically acceptable salts, solvates or prodrugs thereof.

It is intended in the context of the present invention that stereochemical isomers of formula (IB) are enriched in one configuration at centers named 1 and 6. In one embodiment, the isomers correspond in one embodiment to at least 90% e.e. (enantiomeric excess). In another embodiment the isomers correspond to at least 95% e.e. In another embodiment the isomers correspond to at least 99% e.e. From now on throughout the document, the suffix "B" in brackets is used to identify stereochemical isomers of compounds of the invention having the configuration shown above for compounds of formula (IB) at stereogenic centers at positions named 1 and 6.

The term "C_1-4alkyl" refers to an alkyl group having from one to four carbon atoms, in all isomeric forms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert- butyl.

The term 'C3-C6 cycloalkyl group' as used herein means a non aromatic monocyclic hydrocarbon ring of 3 to 6 carbon atom such as, for example, cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl; while unsaturated cycloalkyls include cyclopentenyl and cyclohexenyl, and the like.

The term 'Cs-ecycloalkyld-salkyl' as used herein means an alkyl having from one to three carbon atoms wherein one hydrogen atom is replaced with a C₃-C₆ cycloalkyl group as above defined, for example methylcyclopropane.

The term 'halo C_1-2 alkyl group' as used herein may be a Cr₂ alkyl group as defined before substituted with at least one halogen, preferably fluorine, such as -CH₂CF₃, -CHF₂, Or -CF₃.

The term "halogen" and its abbreviation "halo" refer to fluorine (F), chlorine (Cl), bromine (Br) or iodine (I). Where the term "halo" is used before another group, it indicates that the group is substituted by one or more halogen atoms.

Any of these groups may be attached to the rest of the molecule at any suitable position.

In one embodiment, R₁ is hydrogen or C_1-4 alkyl (for example methyl). In another embodiment, R₁ is hydrogen.

In one embodiment, R₂ is a an unsubstituted α or β naphthyl group. In another embodiment, R₂ is an unsubstituted β naphthyl group. In another embodiment, R₂ is a β naphthyl group, optionally substituted by 1 or 2 groups R₈, each of them being the same or different. In one embodiment, R₃ is hydrogen or a group X, Xi or X₂. In another embodiment, R₃ is hydrogen. In a further embodiment, R₃ is a group X.

In one embodiment, R₄ is hydrogen.

In one embodiment, R₅ is hydrogen.

In one embodiment, R₆ is hydrogen.

In one embodiment, R₇ is hydrogen or a group X, X₁ or X₂. In another embodiment, R₇ is hydrogen. In a further embodiment, R₇ is a group X.

In one embodiment, n is 1 or 2. In another embodiment, n is 1.

In one embodiment, R₁₀ is hydrogen , Ci_-4alkyl, C₃-₆cycloalkyl or C₃-₆cycloalkylCi_-3alkyl. In another embodiment, R₁₀ is hydrogen or C_1-4alkyl. In a still further embodiment, R₁₀ is C_1- ₄alkyl (for example methyl or ethyl).

In one embodiment, R₈ is halogen ( for example chlorine), cyano or C_1-4alkyl. In another embodiment, R₈ is halogen ( for example chlorine).

In one embodiment, a compound of formula (IC) or a pharmaceutically acceptable salt, prodrug or solvate thereof is provided, wherein R₁, R₂ and R₇ are as defined for formula (I):

In Formula (IC), in one embodiment, R₁ is hydrogen or C_1-4 alkyl (for example methyl), R₂ is a β naphthyl group, optionally substituted by 1 or 2 groups R_8, and R₇ is hydrogen or a group X, X₁ or X₂. In Formula (IC), in a further embodiment, R₁ is hydrogen, R₂ is is an unsubstituted β naphthyl group, and R₇ is hydrogen or a group X, Xi or X₂.

In one embodiment, a compound of formula (ID) or a pharmaceutically acceptable salt, prodrug or solvate thereof is provided, wherein R₇ is a group X and R_2, R₁₀ and n are as defined for formula (I):

In Formula (ID), in one embodiment, R₂ is a β naphthyl group, optionally substituted by 1 or 2 groups R₈, and R₁₀ is hydrogen , C_1-4alkyl, C₃-₆cycloalkyl or C₃-₆cycloalkylC_1-3alkyl.

In Formula (ID), in a further embodiment, R₂ is a β naphthyl group, optionally substituted by 1 or 2 groups R₈, n is 1 and R₁₀ is hydrogen or C_1-4alkyl (for example methyl).

In another embodiment, compounds of formula (IC) and (ID) as above defined, having the configuration shown above for compounds of formula (IA) at stereogenic centers at position named 1 and 6, are provided . Those compounds are named (ICA) and (IDA).

In a further embodiment, compounds of formula (IC) and (ID) as above defined, having the configuration shown above for compounds of formula (IB) at stereogenic centers at position named 1 and 6, are provided . Those compounds are named (ICB) and (IDB).

Certain groups/substituents included in the present invention may be present as isomers. The present invention includes within its scope all such isomers, including racemates, enantiomers, tautomers and mixtures thereof.

Certain groups in compounds of formula (I) or in intermediates used to prepare them, may exist in one or more tautomeric forms. The present invention includes within its scope all such tautomeric forms, including mixtures. As used herein, the term "salt" refers to any salt of a compound according to the present invention prepared from an inorganic or organic acid or base, quaternary ammonium salts and internally formed salts and also includes pharmaceutically acceptable salts. Pharmaceutically acceptable salts are particularly suitable for medical applications because of their greater aqueous solubility relative to the parent compounds. Such salts must clearly have a physiologically acceptable anion or cation.

Certain of the compounds of the invention may form acid or base addition salts with one or more equivalents of the acid or of the base. The present invention includes within its scope all possible stoichiometric and non-stoichiometric forms.

Pharmaceutically acceptable salts may also be prepared from other salts, including other pharmaceutically acceptable salts, of the compound of formula (I) using conventional methods.

Suitably pharmaceutically acceptable salts of the compounds of the present invention include acid addition salts formed with inorganic acids such as hydrochloric, hydrobromic, hydroiodic, phosphoric, metaphosphoric, nitric and sulfuric acids, and with organic acids, such as tartaric, acetic, trifluoroacetic, citric, malic, lactic, fumaric, benzoic, naphtoic, formic, propionic, glycolic, gluconic, maleic, succinic, camphorsulfuric, isothionic, mucic, gentisic, isonicotinic, saccharic, glucuronic, furoic, glutamic, ascorbic, anthranilic, salicylic, phenylacetic, mandelic, embonic (pamoic), methanesulfonic, ethanesulfonic, pantothenic, stearic, sulfinilic, alginic, galacturonic and arylsulfonic, for example benzenesulfonic and p-toluenesulfonic, acids; base addition salts formed with alkali metals and alkaline earth metals and organic bases such as N,N-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, meglumaine (N-methylglucamine), lysine and procaine; and internally formed salts. Salts having a non-pharmaceutically acceptable anion or cation are within the scope of the invention as useful intermediates for the preparation of pharmaceutically acceptable salts and/or for use in non-therapeutic, for example, in vitro, situations.

Those skilled in the art of organic chemistry will appreciate that many organic compounds can form complexes with solvents in which they are reacted or from which they are precipitated or crystallized. These complexes are known as "solvates". For example, a complex with water is known as a "hydrate". Solvates of the compounds of the invention are within the scope of the invention. The compounds of formula (I) may readily be isolated in association with solvent molecules by crystallisation or evaporation of an appropriate solvent to give the corresponding solvates.

In addition, prodrugs are also included within the context of this invention. As used herein, the term "prodrug" means a compound which is converted within the body, e.g. by hydrolysis in the blood, into its active form that has medical effects. Pharmaceutically acceptable prodrugs are described in T. Higuchi and V. Stella, Prodrugs as Novel Delivery Systems, Vol. 14 of the A.C.S. Symposium Series, Edward B. Roche, ed., Bioreversible Carriers in Drug Design, American Pharmaceutical Association and Pergamon Press, 1987, and in D. Fleisher, S. Ramon and H. Barbra "Improved oral drug delivery: solubility limitations overcome by the use of prodrugs", Advanced Drug Delivery Reviews (1996) 19(2) 115-130.

Prodrugs are generally prepared by modifying functional groups in a way such that the modification is cleaved, either by routine manipulation or in vivo, yielding the parent compound. Prodrugs include, for example, compounds of this invention wherein hydroxy, amine or sulfhydryl groups are bonded to any group that, when administered to a patient, cleaves to form the hydroxy, amine or sulfhydryl groups. Thus, representative examples of prodrugs include (but are not limited to) acetate, formate and benzoate derivatives of alcohol, sulfhydryl and amine functional groups of the compounds of structure (I). Further, in the case of a carboxylic acid (-COOH), esters may be employed, such as methyl esters, ethyl esters, and the like. Esters may be active in their own right and /or be hydrolysable under in vivo conditions in the human body. Suitable pharmaceutically acceptable in vivo hydrolysable ester groups include those which break down readily in the human body to leave the parent acid or its salt.

Hereinafter, compounds of formula (I) and their pharmaceutically acceptable salts, solvates and prodrugs defined in any aspect of the invention (except intermediate compounds in chemical processes) are referred to as "compounds of the invention".

Furthermore, some of the crystalline forms of the compounds of the present invention, may exist as polymorphs, which are included in the present invention.

Those skilled in the art will appreciate that in the preparation of the compounds of the invention, it may be necessary and/or desirable to protect one or more sensitive groups in the molecule to prevent undesirable side reactions. Suitable protecting groups for use according to the present invention are well known to those skilled in the art and may be used in a conventional manner. See, for example, "Protective groups in organic synthesis" by T.W. Greene and P. G. M. Wuts (John Wiley & sons 1991 ) or "Protecting Groups" by PJ. Kocienski (Georg Thieme Verlag 1994). Examples of suitable amino protecting groups include acyl type protecting groups (e.g. formyl, trifluoroacetyl, acetyl), aromatic urethane type protecting groups (e.g. benzyloxycarbonyl (Cbz) and substituted Cbz), aliphatic urethane protecting groups (e.g. 9-fluorenylmethoxycarbonyl (Fmoc), t- butyloxycarbonyl (Boc), isopropyloxycarbonyl, cyclohexyloxycarbonyl) and alkyl type protecting groups (e.g. benzyl, trityl, chlorotrityl). Examples of suitable oxygen protecting groups may include for example alky silyl groups, such as trimethylsilyl or tert- butyldimethylsilyl; alkyl ethers such as tetrahydropyranyl or tert-butyl; or esters such as acetate.

The present invention also includes isotopically-labelled compounds, which are identical to those recited in formula (I) and following, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be incorporated into compounds of the invention and pharmaceutically acceptable salts thereof include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, sulphur, fluorine, iodine, and chlorine, such as ²H, ³H, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁷O, ¹⁸0, ³¹P, ³²P, ³⁵S, ¹⁸F, ³⁶CI, ¹²³I and ¹²⁵I.

Compounds of the present invention and non-pharmaceutically acceptable salts thereof that contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of the present invention. Isotopically-labelled compounds of the present invention, for example those into which radioactive isotopes such as ³H, ¹⁴C are incorporated, are useful in drug and/or substrate tissue distribution assays. Tritiated, i.e.,

³H, and carbon-14, i.e., ¹⁴C, isotopes are particularly preferred for their ease of preparation and detectability. ¹¹C and ¹⁸F isotopes are particularly useful in PET (positron emission tomography), and ¹²⁵I isotopes are particularly useful in SPECT (single photon emission computerized tomography), all useful in brain imaging. Further, substitution with heavier isotopes such as deuterium, i.e., ²H, can afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements and, hence, may be preferred in some circumstances, lsotopically labelled compounds of the present invention and non-pharmaceutically acceptable salts thereof can generally be prepared by carrying out the procedures disclosed in the Schemes and/or in the Examples below, by substituting a readily available isotopically labelled reagent for a non-isotopically labelled reagent.

In one embodiment, the compounds of the invention are selected from the list consisting of:

(1 S,6S/7/?,6/?)-6-[(methyloxy)methyl]-1-(2-naphthalenyl)-3-azabicyclo[4.1.0]heptane; (1 R,6R or 1 S,6S)-6-[(methyloxy)methyl]-1-(2-naphthalenyl)-3-azabicyclo[4.1.0]heptane (1 S,6S or y/?,6R)-6-[(methyloxy)methyl]-1-(2-naphthalenyl)-3-azabicyclo[4.1.0]heptane; and pharmaceutically acceptable salts, solvates, or prodrugs thereof.

The present invention also provides a process for preparing a compound of formula (I) or a salt thereof as defined above.

Compounds of the invention may be prepared according to the following synthetic schemes, wherein the broadest scope has been defined using formula (I) as basis.

Throughout the specification, general formulae are designated by Roman numerals (I), (II), (III), (IV) etc. Subsets of these general formulae are defined as (Ia), (Ib), (Ic) etc .... (IVa), (IVb), (IVc) etc.

In the following reaction schemes, unless otherwise stated R-| to R-| -| , X, Xi,X₂, X3, and n are as for compounds of formula (I).

Compounds of formula (Ib), i.e. compounds of formula (I) wherein R₁ = C_1-4 alkyl, may be obtained by compounds of formula (Ia), i.e. compounds of formula (I) wherein R₁ = H, following standard alkylation procedures, e. g. using a RX alkylating agent (R = C_1-4 alkyl, X = halogen), such as CH₃I, a trialkylamine, such as TEA, in DCM, at temperature between 0 ⁰C and room temperature, according to Scheme 1.

Scheme 1

(Ia) (Ib)

Compounds of formula (Ia) may be obtained, according to Scheme 2, through reduction of the mixture of compounds (III) and (II) followed by chromatographic separation of the different regioisomers obtained.

Scheme 2.

(III) (H) (Ia)

In particular, the reduction reaction may be performed using borane in THF at refluxing temperature.

Compounds of formula (III) and (II) may be obtained by compounds of formula (IV) via Beckmann rearrangement using tosyl chloride in acetone from room temperature to reflux according to Scheme 3.

(IV) (III)

(H) Compounds of formula (IV) may be obtained from compounds of formula (V) according to Scheme 4 using hydroxylamine monohydrate in ethanol at room temperature.

Scheme 4

Compounds of formula (V) may be obtained from compounds of formula (Vl) according to Scheme 5 by rearrangement of the appropriate propargylic aldehyde in accordance to the method described in J. Am. Chem. Soc. 2004, 126, 8654, after reaction with the allylic derivative (VII) where M can be SiMe₂CI or MgBr .

Scheme 5

(Vl) (VII)

(V)

Compounds of formula (Vl) may be obtained by oxidation with Dess-Martin periodinane in DCM at room temperature from the appropriate alcohol (VIII) according to Scheme 6.

Scheme 6

(VIM) (Vl) Compounds of formula (VIII) may be obtained according to the method described in JOC, 2005, 70, 4043, from propargyl alcohol and the appropriate lodo arene derivative (IX) according to Scheme 7.

Scheme 7

(IX) (VIII)

Compounds of formula (Ic), i.e. compounds of formula (I) wherein R₇ = CH₂OH, may be obtained from compounds of formula (XVI), wherein Pg is a suitable N-protecting group (typically Cbz or Boc), through deprotection of N-Pg group, (such as for Cbz using 6N hydrochloridric acid in dioxane at reflux temperature or for BOC using TFA in DCM at temperature between 0 ⁰C and room temperature) according to Scheme 8.

Scheme 8

(XVI) (Ic)

Compounds of formula (XVI) may be obtained from compounds of formula (X), wherein R₂, R₅, Re are defined as above and Pg is a suitable N-protecting group, according to Scheme 9, through the standard Simmons-Smith cyclopropanation procedure (e.g. using ZnEt₂, CH₂I₂ in DCM).

Scheme 9

(X) (XVl)

Compounds of formula (X) may be obtained from compounds of formula (Xl), according to Scheme 10, using reducing agents, such as LiAIH₄, in aprotic solvent, e. g. diethyl ether or THF, at temperature between -40 and -10 ⁰C.

Compounds of formula (Xl) may be obtained from compounds of formula (XII), according to Scheme 1 1 , through a suitable protecting agent, such as reaction with Cbz-chloride or Boc anhydride, using TEA in DCM at temperature between 0 ⁰C and room temperature.

Scheme 11

Compounds of formula (XII) may be obtained from compounds of formula (XIII), according to Scheme 12, through reaction with 1-chloroethyl chloroformate in DCE and MeOH.

Scheme 12

(XIII) (XII)

Compounds of formula (XIII) may be obtained from compounds of formula (XIV), according to Scheme 13, following the standard Suzuky coupling procedure using the opportune aryl boronic acids or boronate esters, Pd(PPh₃)₄ and a base, e. g. Na₂CO₃ in a mixture of solvent e. g. toluene, ethanol and water at 80 ⁰C.

Scheme 13

(XlV) (XIII)

Compounds of formula (XIV) may be obtained according to Scheme 14 from compounds of formula (XV), by reaction with a base (eg sodium hydride), then with a triflating agent, such as N-phenyltrifluoromethanesulfonimide, in an aprotic solvent (eg DMF), at temperature between 0 ⁰C and room temperature.

Scheme 14

(XV) (XlV) When a specific enantiomer or diastereoisomer of a compound of formula (I)' or salts thereof, is required, this may be obtained for example by resolution of a corresponding enantiomeric or diastereoisomeric mixture using conventional methods.

Thus, for example, specific enantiomers or diastereoisomers of the compounds may be obtained from the corresponding enantiomeric or diastereoisomeric mixture using chiral chromatographic methods such as for example chiral HPLC.

Alternatively, specific enantiomers or diastereoisomers of the compounds may be obtained from the corresponding enantiomeric or diastereoisomeric mixture using chiral crystallization methods such as precipitation with chiral acids.

Furthermore a specific enantiomer or diastereoisomer of a compound of the invention may be synthesised from the appropriate optically active intermediate using any of the general processes described herein.

Alternatively, a specific enantiomer or diastereoisomer of a compound the invention may be synthesised from the appropriate stereochemical^ enriched intermediate using any of the general processes described herein and by combining it with any of the conventional resolution methods above described.

Optically active intermediates or stereochemical^ enriched intermediates, may be generated by resolution of a corresponding enantiomeric or diastereosiomeric mixtures using conventional methods, or by performance of stereoselective reactions or by combining different resolution techniques.

Also specific enantiomers or diastereoisomers of the compounds may be obtained by combining conventional methods above described.

The compounds of the present invention are useful in the treatment of disorders or diseases responsive to the monoamine neurotransmitter re-uptake inhibiting activity of the compounds. This activity of the compounds of the invention may make them useful in the treatment of Parkinsonism, depression, eating disorders, sleep disorders, substance related disorders, attention-deficit hyperactivity disorders, anxiety disorders, cognition impairment, sexual dysfunctions, obsessive compulsive spectrum disorders, Gilles de Ia Tourettes disease and senile dementia, as well as other disorders sensitive to the monoamine neurotransmitter re-uptake-inhibiting activity of the compounds.

Within the context of the present invention, the terms describing some indications used herein are classified in the Diagnostic and Statistical Manual of Mental Disorders, 4th

Edition, published by the American Psychiatric Association (DSM-IV) and/or the

International Classification of Diseases, 10th Edition (ICD-10). The various subtypes of the disorders mentioned herein are contemplated as part of the present invention.

Numbers in brackets after the listed diseases below refer to the classification code in DSM-IV.

The term "depression" includes:

Depression and mood disorders including Major Depressive Episode, Manic Episode, Mixed Episode and Hypomanic Episode; Depressive Disorders including Major

Depressive Disorder, Dysthymic Disorder (300.4), Depressive Disorder Not Otherwise

Specified (31 1 ); Other Mood Disorders including Mood Disorder Due to a General Medical

Condition (293.83) which includes the subtypes With Depressive Features, With Major

Depressive-like Episode, With Manic Features and With Mixed Features), Substance- Induced Mood Disorder (including the subtypes With Depressive Features, With Manic

Features and With Mixed Features) and Mood Disorder Not Otherwise Specified (296.90):

Bipolar Disorders including Bipolar I Disorder, Bipolar Il Disorder (Recurrent Major

Depressive Episodes with Hypomanic Episodes) (296.89), Cyclothymic Disorder (301.13) and Bipolar Disorder Not Otherwise Specified (296.80);

The term "anxiety disorders" includes:

Anxiety disorders including Panic Attack; Panic Disorder including Panic Disorder without Agoraphobia (300.01 ) and Panic Disorder with Agoraphobia (300.21 ); Agoraphobia; Agoraphobia Without History of Panic Disorder (300.22), Specific Phobia (300.29, formerly Simple Phobia) including the subtypes Animal Type, Natural Environment Type, Blood-lnjection-lnjury Type, Situational Type and Other Type), Social Phobia (Social Anxiety Disorder, 300.23), Obsessive-Compulsive Disorder (300.3), Posttraumatic Stress Disorder (309.81 ), Acute Stress Disorder (308.3), Generalized Anxiety Disorder (300.02), Anxiety Disorder Due to a General Medical Condition (293.84), Substance-Induced Anxiety Disorder, Separation Anxiety Disorder (309.21 ), Adjustment Disorders with Anxiety (309.24) and Anxiety Disorder Not Otherwise Specified (300.00):

The term "substance related disorder" includes:

Substance-related disorders including Substance Use Disorders such as Substance Dependence, Substance Craving and Substance Abuse; Substance-Induced Disorders such as Substance Intoxication, Substance Withdrawal, Substance-Induced Delirium, Substance-Induced Persisting Dementia, Substance-Induced Persisting Amnestic Disorder, Substance-Induced Psychotic Disorder, Substance-Induced Mood Disorder, Substance-Induced Anxiety Disorder, Substance-Induced Sexual Dysfunction, Substance- Induced Sleep Disorder and Hallucinogen Persisting Perception Disorder (Flashbacks); Alcohol-Related Disorders such as Alcohol Dependence (303.90), Alcohol Abuse (305.00), Alcohol Intoxication (303.00), Alcohol Withdrawal (291.81 ), Alcohol Intoxication Delirium, Alcohol Withdrawal Delirium, Alcohol-Induced Persisting Dementia, Alcohol-Induced Persisting Amnestic Disorder, Alcohol-Induced Psychotic Disorder, Alcohol-Induced Mood Disorder, Alcohol-Induced Anxiety Disorder, Alcohol-Induced Sexual Dysfunction, Alcohol- Induced Sleep Disorder and Alcohol-Related Disorder Not Otherwise Specified (291.9); Amphetamine (or Amphetamine-I_ike)-Related Disorders such as Amphetamine Dependence (304.40), Amphetamine Abuse (305.70), Amphetamine Intoxication (292.89), Amphetamine Withdrawal (292.0), Amphetamine Intoxication Delirium, Amphetamine Induced Psychotic Disorder, Amphetamine-Induced Mood Disorder, Amphetamine- Induced Anxiety Disorder, Amphetamine-Induced Sexual Dysfunction, Amphetamine- Induced Sleep Disorder and Amphetamine-Related Disorder Not Otherwise Specified (292.9); Caffeine Related Disorders such as Caffeine Intoxication (305.90), Caffeine- Induced Anxiety Disorder, Caffeine-Induced Sleep Disorder and Caffeine-Related Disorder Not Otherwise Specified (292.9); Cannabis-Related Disorders such as Cannabis Dependence (304.30), Cannabis Abuse (305.20), Cannabis Intoxication (292.89), Cannabis Intoxication Delirium, Cannabis-lnduced Psychotic Disorder, Cannabis-lnduced Anxiety Disorder and Cannabis-Related Disorder Not Otherwise Specified (292.9); Cocaine-Related Disorders such as Cocaine Dependence (304.20), Cocaine Abuse (305.60), Cocaine Intoxication (292.89), Cocaine Withdrawal (292.0), Cocaine Intoxication Delirium, Cocaine-Induced Psychotic Disorder, Cocaine-Induced Mood Disorder, Cocaine-Induced Anxiety Disorder, Cocaine-Induced Sexual Dysfunction, Cocaine- Induced Sleep Disorder and Cocaine-Related Disorder Not Otherwise Specified (292.9);

Hallucinogen-Related Disorders such as Hallucinogen Dependence (304.50), Hallucinogen Abuse (305.30), Hallucinogen Intoxication (292.89), Hallucinogen Persisting Perception Disorder (Flashbacks) (292.89), Hallucinogen Intoxication Delirium, Hallucinogen-Induced Psychotic Disorder, Hallucinogen-Induced Mood Disorder, Hallucinogen-Induced Anxiety Disorder and Hallucinogen-Related Disorder Not Otherwise Specified (292.9); Inhalant-Related Disorders such as Inhalant Dependence (304.60), Inhalant Abuse (305.90), Inhalant Intoxication (292.89), Inhalant Intoxication Delirium, Inhalant-Induced Persisting Dementia, Inhalant-Induced Psychotic Disorder, Inhalant- Induced Mood Disorder, Inhalant-Induced Anxiety Disorder and Inhalant-Related Disorder Not Otherwise Specified (292.9); Nicotine-Related Disorders such as Nicotine Dependence (305.1 ), Nicotine Withdrawal (292.0) and Nicotine-Related Disorder Not Otherwise Specified (292.9); Opioid-Related Disorders such as Opioid Dependence (304.00), Opioid Abuse (305.50), Opioid Intoxication (292.89), Opioid Withdrawal (292.0), Opioid Intoxication Delirium, Opioid-lnduced Psychotic Disorder, Opioid-lnduced Mood Disorder, Opioid-lnduced Sexual Dysfunction, Opioid-lnduced Sleep Disorder and Opioid- Related Disorder Not Otherwise Specified (292.9); Phencyclidine (or Phencyclidine-Like)- Related Disorders such as Phencyclidine Dependence (304.60), Phencyclidine Abuse (305.90), Phencyclidine Intoxication (292.89), Phencyclidine Intoxication Delirium, Phencyclidine-lnduced Psychotic Disorder, Phencyclidine-lnduced Mood Disorder, Phencyclidine-lnduced Anxiety Disorder and Phencyclidine-Related Disorder Not Otherwise Specified (292.9); Sedative-, Hypnotic-, or Anxiolytic-Related Disorders such as Sedative, Hypnotic, or Anxiolytic Dependence (304.10), Sedative, Hypnotic, or Anxiolytic Abuse (305.40), Sedative, Hypnotic, or Anxiolytic Intoxication (292.89), Sedative, Hypnotic, or Anxiolytic Withdrawal (292.0), Sedative, Hypnotic, or Anxiolytic Intoxication Delirium, Sedative, Hypnotic, or Anxiolytic Withdrawal Delirium, Sedative-, Hypnotic-, or Anxiolytic-Persisting Dementia, Sedative-, Hypnotic-, or Anxiolytic- Persisting Amnestic Disorder, Sedative-, Hypnotic-, or Anxiolytic-lnduced Psychotic Disorder, Sedative-, Hypnotic-, or Anxiolytic-lnduced Mood Disorder, Sedative-, Hypnotic-, or Anxiolytic-lnduced Anxiety Disorder Sedative-, Hypnotic-, or Anxiolytic-lnduced Sexual Dysfunction, Sedative-, Hypnotic-, or Anxiolytic-lnduced Sleep Disorder and Sedative-, Hypnotic-, or Anxiolytic-Related Disorder Not Otherwise Specified (292.9); Polysubstance- Related Disorder such as Polysubstance Dependence (304.80); and Other (or Unknown) Substance-Related Disorders such as Anabolic Steroids, Nitrate Inhalants and Nitrous Oxide;

The term "Sleep disorder" includes: Sleep disorders including primary sleep disorders such as Dyssomnias such as Primary Insomnia (307.42), Primary Hypersomnia (307.44), Narcolepsy (347), Breathing-Related Sleep Disorders (780.59), Circadian Rhythm Sleep Disorder (307.45) and Dyssomnia Not Otherwise Specified (307.47); primary sleep disorders such as Parasomnias such as Nightmare Disorder (307.47), Sleep Terror Disorder (307.46), Sleepwalking Disorder (307.46) and Parasomnia Not Otherwise Specified (307.47); Sleep Disorders Related to Another Mental Disorder such as Insomnia Related to Another Mental Disorder (307.42) and Hypersomnia Related to Another Mental Disorder (307.44); Sleep Disorder Due to a General Medical Condition; and Substance-Induced Sleep Disorder including the subtypes Insomnia Type, Hypersomnia Type, Parasomnia Type and Mixed Type;

The term "eating disorder" includes:

Eating disorders such as Anorexia Nervosa (307.1 ) including the subtypes Restricting Type and Binge-Eating/Purging Type; Bulimia Nervosa (307.51 ) including the subtypes Purging Type and Nonpurging Type; Obesity; Compulsive Eating Disorder; Binge Eating Disorder; and Eating Disorder Not Otherwise Specified (307.50):

The term "Attention-Deficit/Hyperactivity Disorder" includes:

Attention-Deficit/Hyperactivity Disorder including the subtypes Attention-Deficit /Hyperactivity Disorder Combined Type (314.01 ), Attention-Deficit /Hyperactivity Disorder Predominantly Inattentive Type (314.00), Attention-Deficit /Hyperactivity Disorder Hyperactive-Impulse Type (314.01 ) and Attention-Deficit /Hyperactivity Disorder Not Otherwise Specified (314.9); Hyperkinetic Disorder; Disruptive Behaviour Disorders such as Conduct Disorder including the subtypes childhood-onset type (321.81 ), Adolescent- Onset Type (312.82) and Unspecified Onset (312.89), Oppositional Defiant Disorder (313.81 ) and Disruptive Behaviour Disorder Not Otherwise Specified; and Tic Disorders such as Tourette's Disorder (307.23);

The term "Cognition impairment" includes:

Cognition impairment including cognition impairment in other diseases such as schizophrenia, bipolar disorder, depression, other psychiatric disorders and psychotic conditions associated with cognitive impairment, e.g. Alzheimer's disease; The term "Sexual dysfunctions" includes:

Sexual dysfunctions including Sexual Desire Disorders such as Hypoactive Sexual Desire Disorder (302.71 ), and Sexual Aversion Disorder (302.79); sexual arousal disorders such as Female Sexual Arousal Disorder (302.72) and Male Erectile Disorder (302.72); orgasmic disorders such as Female Orgasmic Disorder (302.73), Male Orgasmic Disorder (302.74) and Premature Ejaculation (302.75); sexual pain disorder such as Dyspareunia (302.76) and Vaginismus (306.51 ); Sexual Dysfunction Not Otherwise Specified (302.70); paraphilias such as Exhibitionism (302.4), Fetishism (302.81 ), Frotteurism (302.89), Pedophilia (302.2), Sexual Masochism (302.83), Sexual Sadism (302.84), Transvestic Fetishism (302.3), Voyeurism (302.82) and Paraphilia Not Otherwise Specified (302.9); gender identity disorders such as Gender Identity Disorder in Children (302.6) and Gender Identity Disorder in Adolescents or Adults (302.85); and Sexual Disorder Not Otherwise Specified (302.9);

The term Obsessive compulsive spectrum disorder" includes:

Obsessive compulsive spectrum disorder including Obsessive compulsive disorders (300.3), somatoform disorders including body dysmorphic disorder (300.7) and hyperchondriasis (300.7), bulimia nervosa (307.51 ), anorexia nervosa (307.1 ), eating disorders not elsewhere classified (307.50) such as binge eating, impulse control disorders not elsewhere classified (including intermitted explosive disorder (312.34), compulsive buying or shopping, repetitive self-mutilation, onychophagia, psychogenic excoriation, kleptomania (312.32), pathological gambling (312.31 ), trichotillomania (312.39) and internet addiction), paraphilia (302.70) and nonparaphilic sexual addictions, Sydeham's chorea, torticollis, autistic disorders (299.0), compulsive hoarding, and movement disorders, including Tourette's syndrome (307.23).

All of the various forms and sub-forms of the disorders mentioned herein are contemplated as part of the present invention.

In an embodiment, compounds of the invention may be useful as analgesics. For example they may be useful in the treatment of chronic inflammatory pain (e.g. pain associated with rheumatoid arthritis, osteoarthritis, rheumatoid spondylitis, gouty arthritis and juvenile arthritis); musculoskeletal pain; lower back and neck pain; sprains and strains; neuropathic pain; sympathetically maintained pain; myositis; pain associated with cancer and fibromyalgia; pain associated with migraine; pain associated with influenza or other viral infections, such as the common cold; rheumatic fever; pain associated with functional bowel disorders such as non-ulcer dyspepsia, non-cardiac chest pain and irritable bowel syndrome; pain associated with myocardial ischemia; post operative pain; headache; toothache; and dysmenorrhea.

Compounds of the invention may be useful in the treatment of neuropathic pain. Neuropathic pain syndromes can develop following neuronal injury and the resulting pain may persist for months or years, even after the original injury has healed. Neuronal injury may occur in the peripheral nerves, dorsal roots, spinal cord or certain regions in the brain. Neuropathic pain syndromes are traditionally classified according to the disease or event that precipitated them. Neuropathic pain syndromes include: diabetic neuropathy; sciatica; non-specific lower back pain; multiple sclerosis pain; fibromyalgia; HIV-related neuropathy; post-herpetic neuralgia; trigeminal neuralgia; and pain resulting from physical trauma, amputation, cancer, toxins or chronic inflammatory conditions. These conditions are difficult to treat and although several drugs are known to have limited efficacy, complete pain control is rarely achieved. The symptoms of neuropathic pain are incredibly heterogeneous and are often described as spontaneous shooting and lancinating pain, or ongoing, burning pain. In addition, there is pain associated with normally non-painful sensations such as "pins and needles" (paraesthesias and dysesthesias), increased sensitivity to touch (hyperesthesia), painful sensation following innocuous stimulation (dynamic, static or thermal allodynia), increased sensitivity to noxious stimuli (thermal, cold, mechanical hyperalgesia), continuing pain sensation after removal of the stimulation (hyperpathia) or an absence of or deficit in selective sensory pathways (hypoalgesia).

Compounds of the invention may also be useful in the amelioration of inflammatory disorders, for example in the treatment of skin conditions (e.g. sunburn, burns, eczema, dermatitis, psoriasis); ophthalmic diseases such as glaucoma, retinitis, retinopathies, uveitis and of acute injury to the eye tissue (e.g. conjunctivitis); lung disorders (e.g. asthma, bronchitis, emphysema, allergic rhinitis, respiratory distress syndrome, pigeon fancier's disease, farmer's lung, chronic obstructive pulmonary disease, (COPD); gastrointestinal tract disorders (e.g. aphthous ulcer, Crohn's disease, atopic gastritis, gastritis varialoforme, ulcerative colitis, coeliac disease, regional ileitis, irritable bowel syndrome, inflammatory bowel disease, gastroesophageal reflux disease); other conditions with an inflammatory component such as migraine, multiple sclerosis, myocardial ischemia.

In one embodiment, compounds of the invention are useful in the treatment of depression and anxiety disorders.

In another embodiment, compounds of the invention are useful in the treatment of depression.

"Treatment" includes prophylaxis, where this is appropriate for the relevant condition(s).

In an alternative or further aspect there is provided a method for the treatment of a mammal, including man, in particular in the treatment of disorders or diseases responsive to the monoamine neurotransmitter re-uptake inhibiting activity of the compounds, comprising administration of an effective amount of a compound of the invention.

In one embodiment, the invention provides a method of treating a condition for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE), is beneficial, which comprises administering to a mammal (e.g. human) in need thereof an effective amount of a compound of the invention.

In another aspect, the invention provides a compound of the invention for use in therapy.

In one embodiment, the invention provides compounds of the invention for use in the treatment of a condition in a mammal for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE) is beneficial.

In one aspect, the invention provides the use of compounds of the invention, for the manufacture of a medicament for the treatment of disorders or diseases responsive to monoamine neurotransmitter re-uptake inhibiting activity.

In one embodiment, the use of compounds of the invention is provided in the manufacture of a medicament for the treatment of a condition in a mammal for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE) is beneficial. The compounds of the invention may also be used in combination with other therapeutic agents. The invention thus provides, in a further aspect, a combination comprising a compound of the invention together with a further therapeutic agent.

The compounds of the invention may be used in combination with the following agents to treat or prevent psychotic disorders: i) antipsychotics; ii) drugs for extrapyramidal side effects, for example anticholinergics (such as benztropine, biperiden, procyclidine and trihexyphenidyl), antihistamines (such as diphenhydramine) and dopaminergics (such as amantadine); iii) antidepressants; iv) anxiolytics; and v) cognitive enhancers for example cholinesterase inhibitors (such as tacrine, donepezil, rivastigmine and galantamine).

The compounds of the invention may be used in combination with antidepressants to treat or prevent depression and mood disorders.

The compounds of the invention may be used in combination with the following agents to treat or prevent bipolar disease: i) mood stabilisers; ii) antipsychotics; and iii) antidepressants.

The compounds of the invention may be used in combination with the following agents to treat or prevent anxiety disorders: i) anxiolytics; and ii) antidepressants.

The compounds of the invention may be used in combination with the following agents to improve nicotine withdrawal and reduce nicotine craving: i) nicotine replacement therapy for example a sublingual formulation of nicotine beta-cyclodextrin and nicotine patches; and ii) bupropion.

The compounds of the invention may be used in combination with the following agents to improve alcohol withdrawal and reduce alcohol craving: i) NMDA receptor antagonists for example acamprosate; ii) GABA receptor agonists for example tetrabamate; and iii) Opioid receptor antagonists for example naltrexone.

The compounds of the invention may be used in combination with the following agents to improve opiate withdrawal and reduce opiate craving: i) opioid mu receptor agonist/opioid kappa receptor antagonist for example buprenorphine; ii) opioid receptor antagonists for example naltrexone; and iii) vasodilatory antihypertensives for example lofexidine. The compounds of the invention may be used in combination with the following agents to treat or prevent sleeping disorders: i) benzodiazepines for example temazepam, lormetazepam, estazolam and triazolam; ii) non-benzodiazepine hypnotics for example Zolpidem, zopiclone, zaleplon and indiplon; iii) barbiturates for example aprobarbital, butabarbital, pentobarbital, secobarbita and phenobarbital; iv) antidepressants; v) other sedative-hypnotics for example chloral hydrate and chlormethiazole.

The compounds of the invention may be used in combination with the following agents to treat anorexia: i) appetite stimulants for example cyproheptidine; ii) antidepressants; iii) antipsychotics; iv) zinc; and v) premenstral agents for example pyridoxine and progesterones.

The compounds of the invention may be used in combination with the following agents to treat or prevent bulimia: i) antidepressants; ii) opioid receptor antagonists; iii) antiemetics for example ondansetron; iv) testosterone receptor antagonists for example flutamide; v) mood stabilisers; vi) zinc; and vii) premenstral agents.

The compounds of the invention may be used in combination with the following agents to treat or prevent autism: i) antipsychotics; ii) antidepressants; iii) anxiolytics; and iv) stimulants for example methylphenidate, amphetamine formulations and pemoline.

The compounds of the invention may be used in combination with the following agents to treat or prevent ADHD: i) stimulants for example methylphenidate, amphetamine formulations and pemoline; and ii) non-stimulants for example norepinephrine reuptake inhibitors (such as atomoxetine), alpha 2 adrenoceptor agonists (such as clonidine), antidepressants, modafinil, and cholinesterase inhibitors (such as galantamine and donezepil).

The compounds of the invention may be used in combination with the following agents to treat personality disorders: i) antipsychotics; ii) antidepressants; iii) mood stabilisers; and iv) anxiolytics.

The compounds of the invention may be used in combination with the following agents to treat or prevent male sexual dysfunction: i) phosphodiesterase V inhibitors, for example vardenafil and sildenafil; ii) dopamine agonists/dopamine transport inhibitors for example apomorphine and buproprion; iii) alpha adrenoceptor antagonists for example phentolamine; iv) prostaglandin agonists for example alprostadil; v) testosterone agonists such as testosterone; vi) serotonin transport inhibitors for example serotonin reuptake inhibitors; v) noradrenaline transport inhibitors for example reboxetine and vii) 5-HT1A agonists, for example flibanserine.

The compounds of the invention may be used in combination with the same agents specified for male sexual dysfunction to treat or prevent female sexual dysfunction, and in addition an estrogen agonist such as estradiol.

Antipsychotic drugs include Typical Antipsychotics (for example chlorpromazine, thioridazine, mesoridazine, fluphenazine, perphenazine, prochlorperazine, trifluoperazine, thiothixine, haloperidol, molindone and loxapine); and Atypical Antipsychotics (for example clozapine, olanzapine, risperidone, quetiapine, aripirazole, ziprasidone and amisulpride).

Antidepressant drugs include serotonin reuptake inhibitors (such as citalopram, escitalopram, fluoxetine, paroxetine and sertraline); dual serotonin/noradrenaline reuptake inhibitors (such as venlafaxine, duloxetine and milnacipran); Noradrenaline reuptake inhibitors (such as reboxetine); tricyclic antidepressants (such as amitriptyline, clomipramine, imipramine, maprotiline, nortriptyline and trimipramine); monoamine oxidase inhibitors (such as isocarboxazide, moclobemide, phenelzine and tranylcypromine); and others (such as bupropion, mianserin, mirtazapine, nefazodone and trazodone).

Mood stabiliser drugs include lithium, sodium valproate/valproic acid/divalproex, carbamazepine, lamotrigine, gabapentin, topiramate and tiagabine.

Anxiolytics include benzodiazepines such as alprazolam and lorazepam.

For use in medicine, the compounds of the present invention are usually administered as a standard pharmaceutical composition. The present invention therefore provides in a further aspect a pharmaceutical composition comprising a compound of the invention and a pharmaceutically (i.e physiologically) acceptable carrier. The pharmaceutical composition can be for use in the treatment of any of the conditions described herein. The compounds of the invention may be administered by any convenient method, for example by oral, parenteral (e.g. intravenous), buccal, sublingual, nasal, rectal or transdermal administration and the pharmaceutical compositions adapted accordingly.

The compounds of the invention which are active when given orally can be formulated as liquids or solids, for example syrups, suspensions or emulsions, tablets, capsules and lozenges.

A liquid formulation will generally consist of a suspension or solution of the compound or salt in a suitable liquid carrier(s) for example an aqueous solvent such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring or colouring agent.

A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations. Examples of such carriers include magnesium stearate, starch, lactose, sucrose and cellulose.

A composition in the form of a capsule can be prepared using routine encapsulation procedures. For example, pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), for example aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.

Typical parenteral compositions consist of a solution or suspension of the compound or salt in a sterile aqueous carrier or parenterally acceptable oil, for example polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.

Compositions for nasal administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution or fine suspension of the active substance in a pharmaceutically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container, which can take the form of a cartridge or refill for use with an atomising device. Alternatively the sealed container may be a unitary dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve which is intended for disposal once the contents of the container have been exhausted. Where the dosage form comprises an aerosol dispenser, it will contain a propellant which can be a compressed gas such as compressed air or an organic propellant such as a fluoro- chlorohydrocarbon. The aerosol dosage forms can also take the form of a pump- atomiser.

Compositions suitable for buccal or sublingual administration include tablets, lozenges and pastilles, wherein the active ingredient is formulated with a carrier such as sugar and acacia, tragacanth, or gelatin and glycerin.

Compositions for rectal administration are conveniently in the form of suppositories containing a conventional suppository base such as cocoa butter.

Compositions suitable for transdermal administration include ointments, gels and patches.

In one embodiment, the composition is in unit dose form such as a tablet, capsule or ampoule.

Each dosage unit for oral administration contains for example from 0.5 to 250 mg (and for parenteral administration contains for example from 0.05 to 25 mg) of a compound of the invention calculated as the free base.

The pharmaceutically acceptable compounds of the invention will normally be administered in a daily dosage regimen (for an adult patient) of, for example, an oral dose of between 1 mg and 500 mg, for example between 1 mg and 400 mg, e.g. between 10 and 250 mg or an intravenous, subcutaneous, or intramuscular dose of between 0.1 mg and 100 mg, for example between 0.1 mg and 50 mg, e.g. between 1 and 25 mg of the compound of the formula (I) or a salt thereof calculated as the free base, the compound being administered 1 to 4 times per day, for example 1 to 2 time a day. In one embodiment, the compound of the invention may be administered once a day. Suitably the compounds will be administered for a period of continuous therapy, for example for a week or more. For oral administration a typical dose may be in the range of 1 to 200 mg per day, for example 60 to 200 mg per day.

When a compound of the invention or a pharmaceutically acceptable derivative thereof is used in combination with a second therapeutic agent active against the same disease state the dose of each compound may differ from that when the compound is used alone.

Appropriate doses will be readily appreciated by those skilled in the art. It will be appreciated that the amount of a compound of the invention required for use in treatment will vary with the nature of the condition being treated and the age and the condition of the patient and will be ultimately at the discretion of the attendant physician or veterinarian.

The combinations referred to above may conveniently be presented for use in the form of a pharmaceutical formulation and thus pharmaceutical formulations comprising a combination as defined above together with a pharmaceutically acceptable carrier or excipient comprise a further aspect of the invention. The individual components of such combinations may be administered either sequentially or simultaneously in separate or combined pharmaceutical formulations by any convenient route.

The invention is also directed to a novel kit-of-parts that is suitable for use in the treatment of disorders as above defined comprising a first dosage form comprising a compound of the invention and a second dosage form comprising another therapeutic agent, for simultaneous, separate or sequential administration.

When administration is sequential, either the compound of the invention or the second therapeutic agent may be administered first. When administration is simultaneous, the combination may be administered either in the same or different pharmaceutical composition.

When combined in the same formulation it will be appreciated that the two compounds must be stable and compatible with each other and the other components of the formulation. When formulated separately they may be provided in any convenient formulation, conveniently in such manner as are known for such compounds in the art.

Biological Assays Cell biology

Generation of BacMam viruses for the expression of hSERT, hNET, and hDAT in mammalian cells

Membranes for the SPA-binding assays are produced by HEK-293F cell infection with BacMam viruses generated for each single human SERT, NET, and DAT transporter. hSERT and hDAT are cloned into pFBMRfA vector whereas hNET is cloned into pFASTBacMami vector. The generation and use of BacMam viruses is described in Condreay JP et al, Proc. Natl. Acad. Sci. USA, 1999, 96:127-132 and Hassan NJ et al, Protein Expression and Purification, 47(2): 591-598, 2006.

Affinity to the human transporters SERT, NET and DAT

The affinities of the compounds of the invention for the human serotonin transporter (SERT), human norepinephrine transporter (NET) and for the human dopamine transporter (DAT) may be determined by one of the assays described below. Such affinity is typically calculated from the IC₅₀ obtained in competition experiments as the concentration of a compound necessary to displace 50% of the radiolabeled ligand from the transporter, and is reported as a "K," value calculated by the following equation: K₁ = ^IC5°

1 + L / K_D where L = radioligand and K₀ = affinity of radioligand for transporter (Cheng and Prusoff, Biochem. Pharmacol. 22:3099, 1973). In the context of the present invention pKi values (corresponding to the antilogarithm of Ki) are used instead of Ki; pKi results are only estimated to be accurate to about 0.3-0.5.

Scintillation Proximity Assay (SPA) for human DAT, NET and SERT binding

• Transduction of HEK-293F cells with hSERT/hDAT/hNET BacMam viruses

The HEK-293F suspension cell line (Invitrogen) is routinely grown in 293_Freestyle Expression media (Invitrogen) in shake flask suspension culture. The culture is transduced with the appropriate transporter BacMam at a MOI (multiplicity of infection) of 100 virus particles per cell and incubated for 48hrs at 37 ⁰C, 5% CO₂ in air, shaken at 90rpm in a humidified shaker incubator. The culture is then harvested by centrifugation at 1000g, 4 ⁰C, for 10 minutes and the cell pellet stored at -80 ⁰C until required. • Preparation of BacMam hSERT/hDAT/hNET-HEL293F cell membranes Transduced cell pellets are re-suspended to 1Ox volume with buffer-A (5OmM HEPES, 1 mM EDTA, 1 mM leupeptin, 25ug/ml_ bacitracin, 1 mM phenylmethylsulfonylfluoride, PMSF, 2μM pepstatin A, pH 7.7) and homogenised with 2x 15 second bursts in a glass Waring blender. The homogenate is then centrifuged for 20 minutes at 50Og. Following this, the supernatant is pooled and centrifuged at 13,00Og for 30 minutes. Pellets are then re-suspended to 4x original pellet volume with buffer-B (5OmM TRIS pH 7.4, 13OmM NaCI) and forced through a 0.8mm needle to give a homogeneous suspension. Membrane aliquots are stored at -80 ⁰C until required. The protein concentration is quantified by Bradford assay.

• SPA-binding assay protocol for hSERT, hNET, and hDAT

The affinity of the compounds of the invention to the hSERT, hNET or hDAT can be also assessed by using the [³H]citalopram, [³H]nisoxetine or [³H]WI N-35, 428 binding assays with the SPA technology on BacMam-recombinant human SERT, NET and DAT membranes produced as described before. With the SPA technology (GE Healthcare, Amersham) only transporter-bound radioactivity can elicit bead excitation thus no separation of the bound/ unbound radioligand is required. The protocol for hSERT binding SPA is based on Trilux beta-counter (Wallac, Perkin- Elmer). Briefly, 0.5μl_ of test compound in neat DMSO (or 1 μM fluoxetine as positive control) is added by 50μl_ of the SPA mixture, containing 2mg/ml_ SPA beads (Amersham RPNQ0001 ), 4μg/ml_ hSERT Bacmam membranes, 0.01 % pluronic F-127, 2.5nM [³H]citalopram in the assay buffer (2OmM HEPES, 145mM NaCI, 5mM KCI, pH 7.3). Incubation are performed at room temperature for at least 2 hours. Counts are stable and could be read up to 3 days.

Alternatively, hDAT hNET and hSERT SPA-binding assays are performed by using a Viewlux beta-counter (Wallac, Perkin-Elmer) with imaging PS-WGA beads (Amersham RPNQ0260) in a final assay volume of 30μl_ and in a 384-well plate format (Greiner 781075). Briefly, 0.3μl_ of test compound in neat DMSO and 0% and 100% effect controls (DMSO for total binding and 10 or 1 μM indatraline as positive control) are added to the wells by using a Hummingbird (Genomic Solutions), followed by the addition of 30μl_ of the SPA mixture, containing 1 mg/ml_ SPA beads (hSERT) or 2mg/ml SPA beads (hDAT and hNET), 40μg/ml or 20μg/ml or 6 μg/ml of hDAT or hNET or hSERT BacMam membranes, 0.02% pluronic F-127, 1OnM [³H]WI N-35,428 or 1 OnM [³H]nisoxetine or 3nM [³H]citalopram for hDAT or hNET or hSERT binding SPA in the assay buffer (2OmM HEPES, 145mM NaCI, 5mM KCI, pH 7.3-7.4). Incubation is performed at room temperature for at least 2 hours, best overnight in the dark. Bound radioactivity is recorded by using a 600s 6x binning and 613nm emission filter with the Viewlux instrument.

It is to be understood that the present invention covers all combinations of particular groups described herein above.

The application of which this description and claims forms part may be used as a basis for priority in respect of any subsequent application. The claims of such subsequent application may be directed to any feature or combination of features described herein. They may take the form of product, composition, process, or use claims and may include, by way of example and without limitation, the following claims.

Claims

1. A compound of formula (I)' or a pharmaceutically acceptable salt, solvate or prodrug thereof:

wherein

R₁ is hydrogen or C_1-4 alkyl;

R₈ is selected from a group consisting of: halogen, cyano, C_1-4alkyl;

R₅ is hydrogen or Ci_-4 alkyl;

R₆ is hydrogen or C_1-4 alkyl;

R₇ is selected in the group consisting of: hydrogen, fluorine, and Ci_-4 alkyl; or corresponds to X, X₁, X₂ or X₃; wherein

X corresponds to:

/Vr_n G O,.

^'R, 10

X_I corresponds to:

^

X₂ corresponds to: fγ^oκ ^X9

O

X₃ corresponds to:

R₃ is hydrogen or Ci_-4 alkyl; or corresponds to X or X₁;

R₄ is hydrogen or C_1-4 alkyl; or corresponds to X or X₁;

R₉ is C_1-4alkyl; R₁₀ is hydrogen , C_1-4alkyl, C₃-₆cycloalkyl or C₃-₆cycloalkylC_1-3alkyl;

R₁₁ is haloC_1-2alkyl; n is 1 or 2.

2. A compound of formula (I)', as claimed in claim 1 , selected from the list consisting of:

3. A method of treating a condition for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE), is beneficial, which comprises administering to a mammal (e.g. human) in need thereof an effective amount of a compound as claimed in of any of claims 1 or 2.

4. A method as claimed in claim 3, wherein the condition to be treated is depression.

5. Use of a compound as claimed in any of claims 1 or 2 in the manufacture of a medicament for the treatment of a condition in a mammal for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE) is beneficial.

6. Use as claimed in claim 5, wherein the condition to be treated is depression.

7. A compound as claimed in any of claims 1 or 2 for use in therapy.

8. A compound as claimed in any of claims 1 or 2 for use in the treatment of a condition in a mammal for which inhibition of serotonin (5-HT), dopamine (DA) and norepinephrine (NE) is beneficial.

9. A compound as claimed in any of claims 1 or 2 for use in the treatment of depression.

10. A pharmaceutical composition comprising a compound as claimed in any of claims 1 or 2 or a pharmaceutically acceptable salt, solvate or prodrug thereof and a pharmaceutically acceptable carrier.