WO2009124883A1

WO2009124883A1 - Novel 1,3-dihydro-benzoimidazol-2-ones as m1 agonists

Info

Publication number: WO2009124883A1
Application number: PCT/EP2009/054000
Authority: WO
Inventors: Benny Bang-Andersen; Gitte Kobberøe MIKKELSEN
Original assignee: H. Lundbeck A/S
Priority date: 2008-04-09
Filing date: 2009-04-03
Publication date: 2009-10-15

Abstract

The present invention relates to novel MI agonistic compounds of the present invention. wherein R1 and R3 are idenpendently selected from H, cyano, halogen, such as F or C1, C_1-6 alkoxy, such as methoxy, or C_1-6alkyI, such as methyl R2 is selected from H and halogen, such as F or C1; Y and Y' are individually selected from C_1-3 alkyl, or Y and Y' together with the carbon atom to which they are attached, form a C_3-7 cyctoalkyl group; and wherein each C_1-3alkyl and C_3-7 cycloalkyl group may be optionally substituted with one or two substituents Z; Z is selected from hydrogen, C_1-3alkyl and halogen, such as F or C1; and their use in the treatment of cognitive impairment associated 1 a. w ith schizophrenia and in the treatment of other diseases mediated b> the muscarinic MI receptor

Description

Novel l,3-dihydro-benzoimidazol-2-ones as Ml agonists

Field of the Invention

The present invention provides compounds that are Ml agonists or partial agonists and as such are useful to treat cognitive impairment in connection with schizophrenia and other disorders or diseases involving the muscarinic Ml receptor. The present invention also provides pharmaceutical compositions comprising compounds of the invention and methods of treating said disorders or diseases using the compounds of the invention.

Background of the Invention

Muscarinic acetyl choline receptors are members of the G protein coupled receptor super family which mediate the action of the neurotransmitter acetylcholine in both the central and peripheral nervous system. Five muscarinic receptor subtypes (M1-M5) have been cloned; the muscarinic Ml receptor is predominantly expressed in the cerebral cortex and hippocampus, although it is also expressed in the periphery e.g. in exocrine glands.

Muscarinic receptors in the central nervous system, especially Ml, play a critical role in mediating higher cognitive processing.

It has been suggested that muscarinic agonists may improve the symptoms of schizophrenia by acting directly at postsynaptic muscarinic receptors in cortical areas (Friedman et al, Biol Psychiatry 1999, 45 1-16). Recently, polymorphism of the Ml muscarinic receptor gene was shown to be associated with a poor cognitive function in subjects with schizophrenia (Liao et al, Neuropsychobiology 2003, 48, 72-76). Data from postmortem studies show a decrease in both the Ml receptor protein and the mRNA levels in prefrontal cortices in human subjects with schizophrenia. These findings have been confirmed by an in vivo brain imaging study in unmedicated subjects with schizophrenia. (Raedler et al, Molecular Psychiatry 2007, 12, 232-246). Altogether this suggests that there is a decrease in Ml receptors in the frontal cortex of schizophrenia, which could result in an under-activation of cholinergic pathways and that activating the Ml receptor would be a mechanism by which cognitive deficits could be reversed in schizophrenia. Alzheimer's disease, which is associated with cognitive impairment, is accompanied by loss of cholinergic neurons in the basal forebrain. Furthermore, in animal models, blockade or lesion of central cholinergic pathways results in profound cognitive deficits.

Cholinergic replacement therapy has largely been using of acetylcholine esterase inhibitors to prevent the breakdown of endogenous acetylcholine. These compounds have shown efficacy with respect to the symptomatic cognitive decline, but have on the other hand given rise to side effects resulting from stimulation of the peripheral muscarinic receptors, giving disturbed gastrointestinal motility and nausea among other things.

In addition to schizophrenia and Alzheimer's Disease, cognitive impairment can be experienced in several patient groups, such as depressive or psychotic patients and patients with attention deficit hyperactivity disorder (ADHD), psychotic disorders such as schizoaffective disorders, psychotic depression, mania, acute mania, Parkinson's disease, mild cognitive impairment (MCI), dementia, anxiety, age associated memory impairment or post-traumatic stress disorder. The cognitive impairment can also be experienced in patients taking benzodiazepines or tricyclic antidepressants and in a range of neurodegenerative diseases, in addition to Parkinson's Disease and Alzheimer's Disease.

Furthermore there is a close link between cognitive impairment and unfavorable post- hospitalization rehabilitation outcomes, especially in elderly patients (SoIh et al., BMC Geriatr. 2006; 6: 12; Hershkovitz et al., Arch. Phys. Medicine and Rehab. 88 (7) 2007, 916- 921, such as postacute stroke rehabilitation (Massucci et al., Am. J. Phys. Medicine & Rehab. 85 (12), 2006 963-970).

Ml receptor agonists or partial agonists could potentially improve cognitive funct in patients suffering from these disorders.

Ml receptor agonists may also be suitable in combination with typical and atypical antipsychotics and other drugs for the treatment of disorders or diseases in the central nervous system, such as mood stabilisers, antidepressants, anxiolytics and drugs for the treatment of extrapyrimidal side effects, to provide improved treatment of psychotic disorders. Moreover, the muscarinic family of receptors is the target for a number of pharmacological agents used for various other diseases, such as chronic obstructive pulmonary disease, asthma, urinary incontinence, glaucoma and pain, including acute pain, chronic pain and neuropathic pain states.

So far, the development of muscarinic Ml receptor agonists for the treatment of cognitive dysfunction or impairment has resulted in a variety of drug candidates, but many have been discontinued from development because of undesirable side effects such as sweating, vomiting and nausea. Therefore, there is a need to develop better therapies to improve the cognitive impairment associated with these disorders and diseases.

Bridges, Thomas M et al, Poster COMC-082 at Frontiers in CNS and Oncology Medicinal Chemistry, ACS-EFMC, Siena, Italy, October 7-9 (2007) disclose certain N-benzyl- and N- benzoyl-[l,4']bipiperidinyl-4-yl)-l,3-dihydro-benzoimidazol-2-ones as Ml allosteric agonists. WO2007107565, WO2007107566 and WO2007107567 further disclose certain 4- alkoxy-cyclohexyl)-piperidin-4-yl]-l,3-dihydro-benzoimidazol-2-one as Ml receptor agonists, whereas WO2007036711, WO2007036715 and WO2007036718 disclose 1-[1- (tetrahydro-pyran-4-yl)-piperidin-4-yl]-l,3-dihydro-benzoimidazol-2-one having effect on the Ml receptor. WO 2004/1089942 and WO 2003/028650 disclose benzimidazolidinone derivatives which increase acetylcholine signaling or effect in the brain, and which are highly selective muscarinic Ml and/or M4 receptor agonists.

None of these references discloses the 1-alkyl- and 1-cycloalkyl- substituted piperidin-4-yl- l,3-dihydro-benzoimidazol-2-ones of the present invention.

WOO 139775 discloses certain compounds as modulators of the opioid and ORL-I receptors, amongst these the compound l-[l-(4-Propyl-cyclohexyl)-piperidin-4-yl]-l,3-dihydrobenzo- imidazol-2-one, which compounds are disclaimed from the present invention.

The compounds of the invention, which are muscarinic Ml receptor agonists, are believed to be useful in the treatment of cognitive impairment associated with schizophrenia, Alzheimer's disease, psychotic disorders such as schizoaffective disorders, psychotic depression, mania, acute mania and with affective disorders such as depression or or bipolar disorder, with memory disorders, and with other diseases mediated by muscarinic receptors, such as chronic obstructive pulmonary disease, asthma, urinary incontinence, glaucoma and pain, including acute pain, chronic pain and neuropathic pain states.

Summary of the Invention

The present invention relates to novel l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-ones, which have been found to be highly active Ml agonists, and as such are likely to be effective in the treatment of cognitive impairment and other diseases mediated by the muscarinic Ml receptor.

One objective of the present invention is thus to provide novel compounds which are Ml receptor agonists.

The present invention further provides compounds, alone or in combination with other antipsychotic agents or other drugs for use in the treatment of disorders or diseases in the central nervous system, for treating or preventing psychosis, such as a schizophrenic disorder or psychosis in Alzheimer's disease or bipolar disorder, for treatment of cognitive impairment associated with schizophrenia, Alzheimer's disease, psychotic disorders such as schizoaffective disorders, psychotic depression, mania, acute mania and with affective disorders such as depression or or bipolar disorder, with memory disorders, and with other diseases mediated by muscarinic receptors, such as chronic obstructive pulmonary disease, asthma, urinary incontinence, glaucoma and pain, including acute pain, chronic pain and neuropathic pain states. The present invention further provides a pharmaceutical composition comprising the compound of the invention and one or more pharmaceutically acceptable carriers, diluents and excipients for treating or preventing said disorders and diseases.

Furthermore, the present invention is also directed to a method for the treatment, control, amelioration or reduction in the risk of developing a disease or disorder where abnormal oscillatory activity occurs in the brain, including depression, migraine, Parkinson's disease, psychosis and schizophrenia, as well as diseases or disorders where there is abnormal coupling of activity, particularly through the thalamus and with other diseases mediated by muscarinic receptors, such as chronic obstructive pulmonary disease, asthma, urinary incontinence, glaucoma and pain, including acute pain, chronic pain and neuropathic pain states.

Further objects of the invention will become apparent upon reading the present specification herein.

Accordingly, in one aspect the present invention relates to a compound of formula I:

wherein

Rl and R3 are individually selected from H, cyano, halogen, such as F and Cl, Ci_6 alkoxy, such as methoxy, or Ci_6 alkyl such as methyl

R2 is selected from H and halogen, such as F or Cl;

Y and Y' are independently selected from Ci_₃ alkyl, or Y and Y,' together with the carbon atom to which they are attached, form a C3_7 cycloalkyl group;

and wherein each Ci_₃ alkyl and C₃_₇ cycloalkyl group may optionally be substituted with one or two substituents Z ;

Z is selected from hydrogen, Ci_₃ alkyl and halogen, such as F or Cl; and enantiomers, diastereomers, tautomers and pharmaceutically acceptable acid addition salts thereof, and polymorphic forms thereof, provided that the compound is not l-[l-(4- Propyl-cyclohexyl)-piperidin-4-yl]-l,3-dihydrobenzoimidazol-2-one.

The invention provides a compound as defined by formula I, or a pharmaceutically acceptable acid addition salt thereof, for use as a medicament.

In another aspect, the invention provides a pharmaceutical composition comprising a therapeutically effective amount of a compound as defined by formula I, or pharmaceutically acceptable acid addition salt thereof, and one or more pharmaceutically acceptable carriers, diluents and excipients.

In a further aspect, the invention relates to compounds as defined by formula I including the compound 1 -[ 1 -(4-Propyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydrobenzoimidazol-2-one which is excluded in formula I as defined above, or pharmaceutically acceptable acid addition salts thereof, for use in the treatment of disorders associated with muscarinic receptors, such as cognitive impairment.

In the following, the expression "a compound of formula I without proviso" or similar wordings used herein shall be understood to mean "a compound of formula I including the compound 1 -[ 1 -(4-Propyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydrobenzoimidazol-2-one".

In yet another aspect, the invention provides a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof, alone or in combination with one or more neuroleptic agents, for use in the treatment of schizophrenia.

The invention further provides a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof, for the preparation of a medicament for use in the treatment of disorders associated with muscarinic receptors, such as cognitive impairment.

The invention further provides a method for the treatment of a disorder selected from the group comprising: cognitive disorders (including age-related cognitive disorder, mild cognitive impairment (MCI), cognitive impairment associated with schizophrenia, and chemotherapy-induced cognitive impairment), ADHD, mood disorders (including depression, mania, bipolar disorders), psychosis (in particular schizophrenia and schizophreniform disorder), dementia (including Alzheimer's disease, AIDS-induced dementia, vascular dementia, and dementia lacking distinctive histology), Parkinson's disease, Huntington's Chorea, pain (including acute pain and chronic pain such as neuropathic pain), xerostomia (dry mouth), Lewy body disease (including diffuse Lewy body disease), aphasia (including primary aphasia and primary aphasia syndromes), hypotensive syndromes, and chronic colitis (including Crohn's disease), comprising: administering to a mammal a therapeutically effective amount of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof.

The present invention also provides a compound as defined by formula I, but without proviso, or a pharmaceutically acceptable acid addition salt thereof, or a pharmaceutical composition thereof, for use in the treatment of disorders associated with muscarinic receptors, such as cognitive impairment.

In separate embodiments of the invention, the compound is selected from one of the specific compounds disclosed in the Experimental Section herein.

Detailed Description of the Invention

Definitions

As used in the present invention, the term "Ci_₃ alkyl" refers to a straight-chain or branched saturated hydrocarbon having from one to three carbon atoms inclusive. Examples of such groups include, but are not limited to, methyl, ethyl, 1 -propyl and 2-propyl.

The term "Ci_6 alkyl" refers to a straight-chain or branched saturated hydrocarbon having from one to six carbon atoms inclusive. Examples of such groups include, but are not limited to, methyl, ethyl, 1 -propyl, 2-propyl, 1 -butyl, 2-butyl, 2-methyl-2-propyl, 2-methyl-l -butyl and n-hexyl.

The expression "Ci_6 alkoxy" refers to a straight-chain or branched saturated alkoxy group having from one to six carbon atoms, inclusive, with the open valency on the oxygen. Examples of such groups include, but are not limited to, methoxy, ethoxy, n-butoxy, 2- methyl-pentoxy and n-hexyloxy.

The term "C3-7 cycloalkyl" typically refers to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.

The compounds of the present invention may have one or more asymmetric centre and it is intended that any optical isomers (i.e. enantiomers or diastereomers), as separated, pure or partially purified optical isomers and any mixtures thereof, including racemic mixtures, are included within the scope of the invention.

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. Separation of such diastereomeric salts can be achieved, e.g. by fractional crystallization. The optically active acids suitable for this purpose may include, but are not limited to d- or 1-tartaric, mandelic or camphorsulfonic acids. Another method for resolving racemates into the optical antipodes is based upon chromatography on an optically active matrix. The compounds of the present invention may also be resolved by the formation and separation, e.g. chromatographic separation, of diastereomeric derivatives from chiral derivatizing reagents, such as a chiral alkylating or acylating reagents, followed by cleavage of the chiral auxiliary. Additional methods for the resolution of optical isomers, known to those skilled in the art, may be used. Such methods include those discussed by J. Jaques, A. Collet and S. Wilen in "Enantiomers, Racemates, and Resolutions", John Wiley and Sons, New York (1981). Optically active compounds can also be prepared from optically active starting materials, or by stereoselective synthesis.

Furthermore, some of the compounds of the present invention may exist in different tautomeric forms and it is intended that any tautomeric forms that the compounds are able to form are included within the scope of the present invention. Some of the compounds of the present invention, including their pharmaceutically acceptable acid addition salts, may exist in different polymorphic forms and it is intended that any polymorphic forms that the compounds are able to form are included within the scope of the present invention.

The phrase "cognitive impairment" as used herein refers to difficulties with attention, learning, memory and executive function (relevant reactions to external stimuli). These can include: deficits in attention, disorganized thinking, slow thinking, difficulty in understanding, poor concentration, impairment of problem solving, poor memory, difficulty in expressing thoughts and/or difficulty in integrating thoughts, feelings and behaviour and extinction of irrelevant thoughts as well as attention and vigilance, verbal learning and memory, visual learning and memory, speed of processing and social cognition.

The term "treatment" as used herein in connection with a disease or disorders such as cognitive impairment includes also prevention as the case may be.

The term "therapeutically effective amount" as used herein shall mean that amount of a compound of formula I, or a pharmaceutically acceptable acid addition salt thereof, that will elicit the biological or medical response of a mammal that is being sought by a researcher or clinician. The therapeutically effective amount will depend on the condition to be treated, the route and duration of administration, the physical attributes of the mammal, including weight and other medications taken concurrently, and may be determined according to methods well known to those skilled in the art in light of the present disclosure.

The mammal treated in the present methods can be a human, male or female, in whom activation of muscarinic Ml receptor activity is desired. Although the present invention is applicable to both old and young people, in certain aspects, such as in treating cognitive impairment associated with Alzheimer's disease, it would find greater application in elderly people.

Accordingly, the present invention includes within its scope the use of a compound of formula I, alone or in combination with other agents, for the treatment of diseases mediated by the muscarinic Ml receptor, such as cognitive impairment and neuropathic pain in a mammal.

The term "leaving group" as used herein refers to a group that is displaced in a substitution or elimination reaction. Typical leaving groups include, but are not limited to, the chloride ion (Cl^"), bromide ion (Br^") and methanesulfonate ion (CH3SO3 ).

As used herein, the term "substantially pure enantiomer" refers to a substance that has between about 95% and 100% of one form (either R or S) and between about 5% and 0% of the other form, alternatively between about 99% and 100% of one form (either R or S) and between about 1% and 0% of the other form, or alternatively between about 99.9% and 100% of one form (either R or S) and about 0.1% and 0% of the other form.

As used herein, the term "substantially pure diastereomer" refers to a substance that has between about 95% and 100% of one diastereomeric form and between about 5% and 0% of the other form, alternatively between about 99% and 100% of one form and between about 1% and 0% of the other form, or alternatively between about 99.9% and 100% of one diastereomeric form and about 0.1% and 0% of the other form.

As used herein, the term rac means a racemic mixture of enantiomers.

wherein Rl and R3 are independently selected from H, cyano, halogen, such as F or Cl, Ci_6 alkoxy, such as methoxy ,or Ci_6 alkyl, such as methyl

R2 is selected from H and halogen, such as F or Cl;

Y and Y' are individually selected from Ci_₃ alkyl, or Y and Y', together with the carbon atom to which they are attached, form a C3_7 cycloalkyl group;

and wherein each Ci_₃ alkyl and C₃_₇ cycloalkyl group may be optionally substituted with one or two substituents Z ;

Z is selected from hydrogen, Ci_₃ alkyl and halogen, such as F or Cl;

and enantiomers, diastereomers, tautomers and pharmaceutically acceptable acid addition salts thereof, and polymorphic forms thereof, provided that the compound is not l-[l-(4- Propyl-cyclohexyl)-piperidin-4-yl]-l,3-dihydrobenzoimidazol-2-one.

In one embodiment of the present invention, Y and Y' are identical. In another embodiment,

Y and Y' are not identical.

In a further embodiment, Y and Y', together with the carbon atom to which they are attached, form a C3_7 cycloalkyl group, which is substituted with one or two substituents Z selected from hydrogen, Ci_3 alkyl and halogen.

In a specific embodiment, the substituted C3_7 cycloalkyl group is 3-methylcyclohexyl. In a different embodiment, the substituted C3_7 cycloalkyl group is 4-methylcyclohexyl. In a further embodiment, the substituted C3_7 cycloalkyl group is 4,4-difluorocyclohexyl.

In another embodiment, Y and Y', together with the carbon atom to which they are attached, form a cyclopropyl group. In another embodiment, Y and Y', together with the carbon atom to which they are attached, form a cyclo butyl group. In a further embodiment, Y and Y', together with the carbon atom to which they are attached, form a cyclopentyl group. In yet another embodiment, Y and Y', together with the carbon atom to which they are attached, form a cyclohexyl group. In a different embodiment, Y and Y', together with the carbon atom to which they are attached, form a cycloheptyl group.

In a specific embodiment of the invention, Rl, R2 and R3 are all hydrogen. In another embodiment, at least one of Rl, R2 and R3 is not hydrogen. In a further embodiment, at least one of Rl, R2 and R3 is hydrogen. In another embodiment, at least one of Rl, R2 and R3 is halogen, such as F and Cl.

In a different embodiment of the invention, Rl is halogen, such as F and Cl. In another embodiment, R2 is halogen, such as F and Cl. In yet another embodiment, R3 is halogen, such as F and Cl.

In a further embodiment, R3 is Ci_₆ alkoxy, such as methoxy. In a different embodiment, R3 is cyano. In yet another embodiment of the invention, R2 and R3 are both halogen, such as F and Cl.

It should be understood that the various aspects, embodiments, implementations or features of the invention mentioned herein can be used and may be claimed individually, or in any combination, which can be illustrated by the following non-limiting examples:

In a specific embodiment, Rl and R2 are both individually selected from hydrogen or halogen, such as fluorine, R3 is selected from hydrogen, Ci_6 alkoxy, such as methoxy, or halogen, such as F and Cl, and Y and Y', together with the carbon atom to which they are attached, form a C3_7 cycloalkyl group, which is substituted with one or two substituents Z selected from hydrogen, Ci_3 alkyl or halogen

In an embodiment of the present invention, the compound of formula I possess an EC50 for binding to the muscarinic Ml receptor of 1 μM or less as evaluated by the CellLux Muscarinic Calcium²⁺ flux assay. In another embodiment, the compound of formula I possesses an EC50 for binding to the muscarinic Ml receptor of 500 nM or less as evaluated by the CellLux Muscarinic Calcium²⁺ flux assay. In another embodiment, the compound of formula I possesses an EC50 for binding to the muscarinic Ml receptor of 100 nM or less as evaluated by the CellLux Muscarinic Calcium²⁺ flux assay assay. In another embodiment, the compound of formula I possesses an EC50 for binding to the muscarinic Ml receptor of 50 nM or less as evaluated by the CellLux Muscarinic Calcium²⁺ flux assay. In another embodiment, the compound of formula I possesses an EC50 for binding to the muscarinic Ml receptor of 10 nM or less as evaluated by the CellLux Muscarinic Calcium²⁺ flux assay.

In a separate embodiment of the invention, the compound of formula I is a substantially pure enantiomer. In another embodiment, the compound of formula I is a substantially pure diastereomer.

In separate embodiments of the invention, the compound of formula I is selected from one of the following specific compounds, either as the free base, tautomers thereof or as a pharmaceutically acceptable acid addition salt thereof:

l-(l-Cyclopentyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one 1 -(I -Cycloheptyl-piperidin-4-yl)-6-fluoro- 1 ,3-dihydro-benzoimidazol-2-one

1 -[ 1 -(4-Methyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydro-benzoimidazol-2-one 6-Chloro-5-fluoro- 1-[ 1 -(3-methyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydro- benzoimidazol-2-one l-(l-Cyclohexyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one l-(l-Cycloheptyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

5-Chloro- 1 -(I -cyclopentyl-piperidin-4-yl)- 1 ,3-dihydro-benzoimidazol-2-one l-(l-Cycloheptyl-piperidin-4-yl)-5-fluoro-l,3-dihydro-benzoimidazol-2-one l-(l-Cyclopentyl-piperidin-4-yl)-4-fluoro-l,3-dihydro-benzoimidazol-2-one 4-Fluoro- 1-[ 1 -(4-methyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydro-benzoimidazol-2-one 6-Chloro-5-fluoro-l-(l-isopropyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

4-Fluoro-l-(l-isopropyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one 3-[l-(3-Methyl-cyclohexyl)-piperidin-4-yl]-2-oxo-2,3-dihydro-lH-benzoimidazole-5- carbonitrile l-(l-Cyclobutyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one 6-Chloro-l-(l-cyclobutyl-piperidin-4-yl)-5-fluoro-l,3-dihydro-benzoimidazol-2-one l-[l-(l-Ethyl-propyl)-piperidin-4-yl]-6-methoxy-l,3-dihydro-benzoimidazol-2-one 6-Chloro- 1 -[ 1 -(l-ethyl-propyl)-piperidin-4-yl]-5-fluoro- 1 ,3-dihydro-benzoimidazol-2- one 1 -[ 1 -(4,4-Difluoro-cyclohexyl)-piperidin-4-yl]-6-methoxy- 1 ,3-dihydro-benzoimidazol-2- one

6-Chloro- 1 -[ 1 -(4,4-difluoro-cyclohexyl)-piperidin-4-yl]-5-fluoro- 1 ,3-dihydro- benzoimidazol-2-one

Each of these compounds is considered an individual embodiment, and may be made the subject of individual claims.

Pharmaceutically Acceptable Salts The present invention comprises pharmaceutically acceptable acid addition salts of the compounds of formula I. Such salts include salts of inorganic acids as well as organic acids.

Representative examples of suitable inorganic acids include hydrochloric, hydrobromic, hydroiodic, phosphoric, sulfuric, sulfamic, nitric acids and the like. Representative examples of suitable organic acids include formic, acetic, trichloroacetic, trifluoroacetic, propionic, benzoic, cinnamic, citric, fumaric, glycolic, itaconic, lactic, methanesulfonic, maleic, malic, malonic, mandelic, oxalic, picric, pyruvic, salicylic, succinic, methane sulfonic, ethanesulfonic, tartaric, ascorbic, pamoic, bismethylene salicylic, ethanedisulfonic, gluconic, citraconic, aspartic, stearic, palmitic, EDTA, glycolic, p-aminobenzoic, glutamic, benzenesulfonic, p-toluenesulfonic acids, theophylline acetic acids, as well as the 8- halotheophyllines, for example 8 -bromo theophylline and the like.

Furthermore, the compounds of this invention may exist in unsolvated as well as in solvated forms with pharmaceutically acceptable solvents such as water, ethanol and the like. In general, the solvated forms are considered equivalent to the unsolvated forms for the purposes of this invention.

Pharmaceutical compositions

The present invention further provides a pharmaceutical composition comprising a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable acid addition salt thereof, and a pharmaceutically acceptable carrier or diluent.

The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of one of the specific compounds disclosed in the Experimental Section herein and a pharmaceutically acceptable carrier or diluent.

The compounds of the invention may be administered alone or in combination with pharmaceutically acceptable carriers, diluents or excipients, in either single or multiple doses.

The pharmaceutical compositions according to the invention may be formulated with pharmaceutically acceptable carriers or diluents as well as any other known adjuvants and excipients in accordance with conventional techniques such as those disclosed in Remington: The Science and Practice of Pharmacy, 19^th Edition, Gennaro, Ed., Mack Publishing Co., Easton, PA, 1995.

The pharmaceutical compositions may be specifically formulated for administration by any suitable route such as oral, rectal, nasal, pulmonary, topical (including buccal and sublingual), transdermal, intracisternal, intraperitoneal, vaginal and parenteral (including subcutaneous, intramuscular, intrathecal, intravenous and intradermal) routes. It will be appreciated that the route will depend on the general condition and age of the mammal to be treated, the nature of the condition to be treated and the active ingredient.

Pharmaceutical compositions for oral administration include solid dosage forms such as capsules, tablets, dragees, pills, lozenges, powders and granules. Where appropriate, the compositions may be prepared with coatings such as enteric coatings or they may be formulated so as to provide controlled release of the active ingredient such as sustained or prolonged release according to methods well known in the art. Liquid dosage forms for oral administration include solutions, emulsions, suspensions, syrups and elixirs.

Pharmaceutical compositions for parenteral administration include sterile aqueous and nonaqueous injectable solutions, dispersions, suspensions or emulsions as well as sterile powders to be reconstituted in sterile injectable solutions or dispersions prior to use. Other suitable administration forms include, but are not limited to, suppositories, sprays, ointments, creams, gels, inhalants, dermal patches and implants.

Typical oral dosages of a compound of formula I range from about 0.001 to about 100 mg/kg body weight per day, calculated as the free base. Typical oral dosages also range from about 0.01 to about 50 mg/kg body weight per day. Typical oral dosages further range from about 0.05 to about 10 mg/kg body weight per day. Oral dosages are usually administered in one or more dosages, typically, one to three dosages per day. The exact dosage will depend upon the frequency and mode of administration, the sex, age, weight and general condition of the mammal treated, the nature and severity of the condition treated and any concomitant diseases to be treated and other factors evident to those skilled in the art.

The formulations may also be presented in a unit dosage form by methods known to those skilled in the art. For illustrative purposes, a typical unit dosage form for oral administration may contain from about 0.01 to about 1000 mg, from about 0.05 to about 500 mg, or from about 0.5 mg to about 200 mg of a compound of formula I, calculated as the free base.

For parenteral routes such as intravenous, intrathecal, intramuscular and similar administration, typical doses are in the order of half the dose employed for oral administration.

The present invention also provides a process for making a pharmaceutical composition comprising admixing a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable acid addition salt thereof, and at least one pharmaceutically acceptable carrier or diluent. In an embodiment of the present invention, the compound utilized in the aforementioned process is one of the specific compounds disclosed in the Experimental Section herein.

The compounds of this invention are generally utilized as the free base or as a pharmaceutically acceptable acid addition salt thereof. Such salts are prepared in a conventional manner by treating a solution or suspension of a free base of formula I with a molar equivalent of a pharmaceutically acceptable acid. Representative examples of suitable organic and inorganic acids are described above.

For parenteral administration, solutions of the compounds of formula I or pharmaceutically acceptable acid addition salts thereof, in sterile aqueous solution, aqueous propylene glycol, aqueous vitamin E or sesame or peanut oil may be employed. Such aqueous solutions should be suitably buffered if necessary and the liquid diluent first rendered isotonic with sufficient saline or glucose. The aqueous solutions are particularly suitable for intravenous, intramuscular, subcutaneous and intraperitoneal administration. The compounds of formula I or pharmaceutically acceptable acid addition salts thereof, may be readily incorporated into known sterile aqueous media using standard techniques known to those skilled in the art.

Suitable pharmaceutical carriers include inert solid diluents or fillers, sterile aqueous solutions and various organic solvents. Examples of solid carriers include lactose, terra alba, sucrose, cyclodextrin, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid and lower alkyl ethers of cellulose. Examples of liquid carriers include, but are not limited to, syrup, peanut oil, olive oil, phospholipids, fatty acids, fatty acid amines, polyoxyethylene and water. Similarly, the carrier or diluent may include any sustained release material known in the art, such as glyceryl monostearate or glyceryl distearate, alone or mixed with a wax. The pharmaceutical compositions formed by combining the compounds of formula I, or pharmaceutically acceptable acid addition salts thereof, and a pharmaceutically acceptable carrier are then readily administered in a variety of dosage forms suitable for the disclosed routes of administration. The formulations may conveniently be presented in unit dosage form by methods known in the art of pharmacy.

Formulations of the present invention suitable for oral administration may be presented as discrete units such as capsules or tablets, each containing a predetermined amount of the active ingredient, and optionally a suitable excipient. Furthermore, the orally available formulations may be in the form of a powder or granules, a solution or suspension in an aqueous or non-aqueous liquid, or an oil- in- water or water-in-oil liquid emulsion.

If a solid carrier is used for oral administration, the preparation may be tab letted, placed in a hard gelatin capsule in powder or pellet form or it may be in the form of a troche or lozenge. The amount of solid carrier will vary widely but will range from about 25 mg to about 1 g per dosage unit. If a liquid carrier is used, the preparation may be in the form of a syrup, emulsion, soft gelatin capsule or sterile injectable liquid such as an aqueous or non-aqueous liquid suspension or solution. The pharmaceutical compositions of the invention may be prepared by conventional methods in the art. For example, tablets may be prepared by mixing the active ingredient with ordinary adjuvants and/or diluents and subsequently compressing the mixture in a conventional tabletting machine prepare tablets. Examples of adjuvants or diluents comprise: corn starch, potato starch, talcum, magnesium stearate, gelatine, lactose, gums, and the like. Any other adjuvants or additives usually used for such purposes such as colourings, flavourings, preservatives etc. may be used provided that they are compatible with the active ingredients.

Treatment of Disorders

As mentioned above, the compounds of formula I are agonists at the Ml receptor and as such are useful for treating or reducing the severity of a Ml muscarinic receptor mediated diseases such as cognitive impairment and neuropathic pain.

The phrase "treating or reducing the severity of a Ml muscarinic receptor mediated disease" refers both to treatments for diseases that are directly caused by muscarinic activities and alleviation of symptoms of diseases not directly caused by muscarinic activities. Examples of diseases whose symptoms may be affected by muscarinic activity include, but are not limited to, CNS derived pathologies including cognitive disorders, Attention Deficit Hyperactivity Disorder (ADHD), obesity, Alzheimer's disease, various dementias such as vascular dementia, psychosis including schizophrenia, mania, bipolar disorders, pain conditions including acute and chronic syndromes such as neuropathic pain, Huntington's Chorea, Friederich's ataxia, Gilles de La Tourette's Syndrome, Down's Syndrome, Pick's disease, clinical depression, Parkinson's disease, peripheral disorders such as reduction of intraocular pressure in Glaucoma and treatment of dry eyes and dry mouth (xerostomia) including Sjogren's Syndrome, bradhycardia, gastric acid secretion, asthma, GI disturbances and wound healing.

The present invention thus provides a method of treating a mammal suffering from cognitive impairment, which comprises administering to the mammal a therapeutically effective amount of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof. This invention also provides a method of treating a mammal suffering from cognitive impairment associated with a psychiatric disorder, which comprises administering to the mammal a therapeutically effective amount of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof. Examples of psychiatric disorders include, but are not limited to, schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type; delusional disorder; substance-induced psychotic disorder, for example psychosis induced by alcohol, amphetamine, cannabis, cocaine, hallucinogens, inhalants, opioids, or phencyclidine; personality disorder of the paranoid type; and personality disorder of the schizoid type; and anxiety disorder selected from panic disorder; agoraphobia; a specific phobia; social phobia; obsessive-compulsive disorder; post-traumatic stress disorder; acute stress disorder; and generalized anxiety disorder.

The present invention provides a method of treating a mammal suffering from cognitive impairment associated with a cognition disorder, which comprises administering to the mammal a therapeutically effective amount of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof. Examples of cognition disorders include, but are not limited to, Alzheimer's disease, multi-infarct dementia, alcoholic dementia or other drug-related dementia, dementia associated with intracranial tumors or cerebral trauma, dementia associated with Huntington's disease or Parkinson's disease, or AIDS-related dementia; delirium; amnestic disorder; post-traumatic stress disorder; mental retardation; a learning disorder, for example reading disorder, mathematics disorder, or a disorder of written expression; attention-deficit/hyperactivity disorder (ADHD); and age-related cognitive decline.

The compounds as defined by formula I but without proviso, or pharmaceutically acceptable acid addition salts thereof may be used in combination with one or more other drugs in the treatment of diseases or conditions for which the compounds of the present invention have utility, where the combination of the drugs together are safer or more effective than either drug alone. Additionally, the compounds of the present invention may be used in combination with one or more other drugs that treat, prevent, control, ameliorate, or reduce the risk of side effects or toxicity of the compounds of the present invention. Such other drugs may be administered, by a route and in an amount commonly used therefore, contemporaneously or sequentially with the compounds of the present invention. Accordingly, the pharmaceutical compositions of the present invention include those that contain one or more other active ingredients, in addition to the compounds of the present invention. The combinations may be administered as part of a unit dosage form combination product, or as a kit or treatment protocol wherein one or more additional drugs are administered in separate dosage forms as part of a treatment regimen.

It has thus been found that the compounds as defined by formula I but without proviso, or pharmaceutically acceptable acid addition salts thereof, may advantageously be administered in combination with at least one neuroleptic agent (which may be a typical or atypical antipsychotic agent) to provide improved treatment of schizophrenia. The combinations, uses and methods of treatment of the invention may also provide advantages in treatment of patients who fail to respond adequately or who are resistant to other known treatments.

The present invention provides a method of treating a mammal suffering from schizophrenia comprising administering to the mammal in need thereof a therapeutically effective amount of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof, either alone or as combination therapy with at least one neuroleptic agent.

The term "neuroleptic agent" as used herein refers to drugs, which have the effect on cognition and behaviour of antipsychotic agent drugs that reduce confusion, delusions, hallucinations, and psychomotor agitation in patients with psychoses. Also known as major tranquilizers and antipsychotic drugs, neuroleptic agents include, but are not limited to: typical antipsychotic drugs, including phenothiazines, further divided into the aliphatics, piperidines, and piperazines, thioxanthenes (e.g., cisordinol), butyrophenones (e.g., haloperidol), dibenzoxazepines (e.g., loxapine), dihydroindolones (e.g., molindone), diphenylbutylpiperidines (e.g., pimozide), and atypical antipsychotic drugs, including benzisoxazoles (e.g., risperidone), sertindole, olanzapine, quetiapine, osanetant and ziprasidone. The expression "co-administration of a neuroleptic agent" as used herein refers to the administration of a compound as defined by formula I, or pharmaceutically acceptable acid addition salts thereof, in combination with at least one neuroleptic agent such as sertindole, olanzapine, risperidone, quetiapine, aripiprazole, haloperidol, clozapine, ziprasidone and osanetant.

Other examples of combinations of the compounds as defined by formula I but without proviso include combinations with anti-Alzheimer's Disease agents, for example beta- secretase inhibitors; alpha 7 nicotinic agonists, such as ABT089, SSRl 80711 and MEM63908; gamma-secretase inhibitors, such as LY450139 and TAK 070; tau phosphorylation inhibitors; blockers of Aβ oligomer formation; 5-HT4 agonists, such as PRX-03140; 5-HT6 antagonists, such as GSK 742467, SGS-518, FK-962, SL- 65.0155, SRA-333 and xaliproden; 5-HT1 a antagonists, such as lecozotan; p25/CDK5 inhibitors; NKl /NK3 receptor antagonists; COX-2 inhibitors; HMG-CoA reductase inhibitors; NSAIDs including ibuprofen; vitamin E; anti-amyloid antibodies (including anti-amyloid humanized monoclonal antibodies), such as bapineuzumab, ACCOOl, CAD 106, AZD3102, Hl 2Al IVl; anti-inflammatory compounds such as (R)-flurbiprofen, nitroflurbiprofen, rosiglitazone, ND- 1251, VP-025, HT-0712 and EHT-202; CB-I receptor antagonists or CB-I receptor inverse agonists, such as AVE 1625; antibiotics such as doxycycline and rifampin; N-methyl-D- aspartate (NMD A) receptor antagonists, such as memantine, neramexane and EVTlOl ; cholinesterase inhibitors such as galantamine, rivastigmine, donepezil, tacrine, phenserine, ladostigil and ABT- 089; growth hormone secretagogues such as ibutamoren, ibutamoren mesylate, and capromorelin; histamine H3 receptor antagonists such as ABT-834, ABT 829, GSK 189254 and CEP 16795; AMPA agonists or AMPA modulators, such as CX-717, LY 451395, LY404187 and S-18986; PDE IV inhibitors, including MEM1414, HT0712 and AVE8112; GABAA inverse agonists; GSK3β inhibitors, including AZD1080, SAR502250 and CEP 16805; neuronal nicotinic agonists; selective Ml agonists; and microtubule affinity regulating kinase (MARK) ligands; or other drugs that affect receptors or enzymes that either increase the efficacy, safety, convenience, or reduce unwanted side effects or toxicity of the compounds of the present invention.

Examples of combinations of the compounds as defined by formula I but without proviso include combinations with agents for use in the treatment of pain, for example non-steroidal anti-inflammatory agents, such as aspirin, diclofenac, duflunisal, fenoprofen, flurbiprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, naproxen, oxaprozin, piroxicam, sulindac and tolmetin; COX-2 inhibitors, such as celecoxib, rofecoxib, valdecoxib, 406381 and 644784; CB-2 agonists, such as 842166 and SAB378; VR-I antagonists, such as AMG517, 705498, 782443, PAC20030, Vl 14380 and A425619; bradykinin B 1 receptor antagonists, such as SSR240612 and NVPSAA164; sodium channel blockers and antagonists, such as VX409 and SPI860; nitric oxide synthase (NOS) inhibitors (including iNOS and nNOS inhibitors), such as SD6010 and 274150; glycine site antagonists, including lacosamide; neuronal nicotinic agonists, such as ABT 894; NMDA antagonists, such as AZD4282; potassium channel openers; AMPA/kainate receptor antagonists; calcium channel blockers, such as ziconotide and NMED 160; GABA-A receptor IO modulators (e.g., GABA- A receptor agonists); matrix metalloprotease (MMP) inhibitors; thrombolytic agents; opioid analgesics such as codeine, fentanyl, hydromorphone, levorphanol, meperidine, methadone, morphine, oxycodone, oxymorphone, pentazocine, propoxyphene; neutrophil inhibitory factor (NIF); pramipexole, ropinirole; anticholinergics; amantadine; monoamine oxidase B15 ("MAO-B") inhibitors; 5HT receptor agonists or antagonists; mGlu5 antagonists, such as AZD9272; neuronal nicotinic agonists, such as ABT894; NMDA receptor agonists or antagonists, such as AZD4282; NKI antagonists; with antidepressants, including SSRIs and SNRIs such as escitalopram, citalopram, fluoxetine, duloxetine paroxetine, and venlafaxine; tricyclic antidepressant drugs, norepinephrine modulators; lithium; valproate; gabapentin; pregabalin; rizatriptan; zolmitriptan; naratriptan and sumatriptan.

The compounds of the invention may also be administered in combination with compounds useful for enhancing sleep quality and preventing and treating sleep disorders and sleep disturbances, including e.g., sedatives, hypnotics, anxiolytics, antipsychotics, antianxiety agents, antihistamines, benzodiazepines, barbiturates, cyclopyrrolones, orexin antagonists, alpha- 1 antagonists, GABA agonists, 5HT-2 antagonists including 5HT-2A antagonists and 5HT-2A/2C antagonists, histamine antagonists including histamine H3 antagonists, histamine H3 inverse agonists, imidazopyridines, minor tranquilizers, melatonin agonists and antagonists, melatonergic agents, other orexin antagonists, orexin agonists, prokineticin agonists and antagonists, pyrazolopyrimidines, T-type calcium channel antagonists, triazolopyridines, and the like, such as: adinazolam, allobarbital, alonimid, alprazolam, amitriptyline, amobarbital, amoxapine, armodafϊnil, APD- 125, bentazepam, benzoctamine, brotizolam, bupropion, busprione, butabarbital, butalbital, capromorelin, capuride, carbocloral, chloral betaine, chloral hydrate, chlordiazepoxide, circadin, clomipramine, clonazepam, cloperidone, clorazepate, clorethate, clozapine, conazepam, cyprazepam, desipramine, dexclamol, diazepam, dichloralphenazone, divalproex, diphenhydramine, doxepin, EMD-281014, eplivanserin, estazolam, eszopiclone, ethchlorynol, etomidate, fenobam, flunitrazepam, flurazepam, fluvoxamine, fluoxetine, fosazepam, gaboxadol, glutethimide, halazepam, hydroxyzine, ibutamoren, imipramine, indiplon, lithium, lorazepam, lormetazepam, LY-156735, maprotiline, MDL-100907, mecloqualone, melatonin, mephobarbital, meprobamate, methaqualone, methyprylon, midaflur, midazolam, modafinil, nefazodone, NGD-2-73, nisobamate, nitrazepam, nortriptyline, oxazepam, paraldehyde, paroxetine, pentobarbital, perlapine, perphenazine, phenelzine, phenobarbital, prazepam, promethazine, propofol, protriptyline, quazepam, ramelteon, reclazepam, roletamide, secobarbital, sertraline, suproclone, TAK-375, temazepam, thioridazine, tiagabine, tracazolate, tranylcypromaine, trazodone, triazolam, trepipam, tricetamide, triclofos, trifluoperazine, trimetozine, trimipramine, uldazepam, venlafaxine, zaleplon, zolazepam, zopiclone, Zolpidem, and salts thereof, and combinations thereof, or the compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof, may be administered in conjunction with the use of physical methods such as with light therapy or electrical stimulation.

The compounds of the invention may also be administered in combination with levodopa (with or without a selective extracerebral decarboxylase inhibitor such as carbidopa or benserazide), anticholinergics such as biperiden (optionally as its hydrochloride or lactate salt) and trihexyphenidyl (benzhexol) hydrochloride, COMT inhibitors such as entacapone, MOA-B inhibitors, antioxidants, A2a adenosine receptor antagonists, cholinergic agonists and dopamine receptor agonists such as alentemol, bromocriptine, fenoldopam, lisuride, naxagolide, pergolide and pramipexole.

The combination therapies of the invention can be administered adjunctively. By adjunctive administration is meant the concurrent or overlapping administration of each of the components in the form of separate pharmaceutical compositions or devices. This regime of therapeutic administration of two or more therapeutic agents is referred to generally by those skilled in the art and herein as adjunctive therapeutic administration; it is also known as addon therapeutic administration.

In a further aspect,, the invention provides a method of treatment of schizophrenia by adjunctive therapeutic administration of a compound as defined by formula I but without proviso, or a pharmaceutically acceptable acid addition salt thereof, to a mammal in need thereof receiving therapeutic administration of at least one neuroleptic agent.

In specific embodiments, the present invention provides methods of treating disorders selected from the group consisting of: cognitive disorders (including age-related cognitive disorder, mild cognitive impairment, cognitive impairment associated with schizophrenia, and chemotherapy-induced cognitive impairment), ADHD, mood disorders (including depression, mania, bipolar disorders), psychosis (in particular schizophrenia and schizophreniform disorder), dementia (including Alzheimer's disease, AIDS-induced dementia, vascular dementia, and dementia lacking distinctive histology), Parkinson's disease, Huntington's Chorea, pain (including acute pain and chronic pain), xerostomia (dry mouth), Lewy body disease (including diffuse Lewy body disease), aphasia (including primary aphasia and primary aphasia syndromes), hypotensive syndromes, and chronic colitis (including Crohn's disease), comprising: administering to a mammal an effective amount of a compound of the present invention. That is, the present invention provides for the use of a compound of the present invention or pharmaceutical composition thereof for use in the treatment disorders associated with muscarinic receptors.

Of the disorders to be treated according to the present invention a number are particularly preferred. Particularly preferred disorders include the treatment of cognitive disorders (particularly mild cognitive impairment and cognitive impairment associated with schizophrenia), Alzheimer's disease, and psychosis, including schizophrenia.

The present invention will be better understood from the Experimental Section that follows.

However, one skilled in the art will readily appreciate that the specific methods and results discussed therein are merely illustrative of the invention as described more fully in the claims that follow thereafter. Experimental Section

General Methods LC-MS: API 150EX and Shimadzu LCIOAD/SLC-IOA LC system. Column: 30 x 4.6 mm Waters Atlantis dC18 with 3 μM particles operated at 40 °C. Solvent system: A = water/TFA (100:0.05) and B = water/acetonitrile/TFA (5:95:0.035). Linear Gradient elution with 2% B to 100% B in 2.4 min and a flow rate of 3.3 ml/min. Retention times (RT) are expressed in minutes. MS instruments are from PESciex (API), equipped with APPI-source and operated in positive ion mode.

¹H NMR spectra were recorded at 500.13 MHz on a Bruker Avance AV500 instrument or at 250.13 MHz on a Bruker Avance DPX250 instrument. TMS was used as internal reference standard. Chemical shift values are expressed in ppm. The following abbreviations are used for multiplicity of NMR signals: s = singlet, d = doublet, t = triplet, q = quartet, qui = quintet, h = heptet, dd = double doublet, dt = double triplet, dq = double quartet, tt = triplet of triplets, m = multiplet, br s = broad singlet and br = broad signal.

Preparation of the compounds of the invention

The compounds of the invention may be prepared by the following general methods:

Reaction of a compound with formula II

II wherein Rl - R3 are as defined above, a) with a compound of formula III

III

wherein Y and Y' are as defined above,

in the presence of a suitable reducing agent, such as sodium triacetoxy borohydride, in a suitable solvent, such as 1,2-DCE or THF, at a suitable temperature, such as room temperature, and in the presence or absence of a suitable acid, such as acetic acid.

b) with a compound of formula X

z X wherein Z is a leaving group, such as chloride, bromide, and Y and Y' are as defined above,

in a suitable solvent, such as DMF, in the presence of a suitable base, such as N₅N- diisopropylethylamine, at a suitable temperature, such as 0-120°C. The base may be immobilized on a solid support such as polystyrene beads.

The compounds with formula II were commercially available or may be prepared by standard procedures known to person skilled in the art, as outlined below: Deprotection of a compound with structure IV:

wherein Rl - R3 are as defined above and PG is a suitable protecting group, such as Boc or carbethoxy.

Deprotection of compounds with structure IV can be accomplished using standard procedures known to the skilled person, such as treatment with a suitable acid, such as HCl or TFA, at a suitable temperature, such as room temperature, and in a suitable solvent, such as ether or methanol or dichloromethane (for removal of the Boc group), or treatment with a suitable base, such as 6M NaOH (aq.), with a suitable co-solvent, such as MeOH, at a suitable temperature, such as reflux temperature (for removal of the carbethoxy group).

Compounds of formula IV may be prepared by standard procedures known to the skilled person. This includes reaction of compounds of formula V

wherein R1-R3 and PG are as defined above, with a suitable reagent VI

VI wherein E and E' are leaving groups, such as chloride or trichloromethoxy or imidazole, and may be the same or different.

The reaction of compounds of formula V with compounds of formula VI may be accomplished using standard procedures known to the skilled person. This includes reacting compounds of formula V with carbonyl diimidazole (E = E' = imidazole) in a suitable solvent, such as acetonitrile, at a suitable temperature, such as 20-80 °C; or reacting compounds of formula V with carbonic acid di-trichloromethyl ester "triphosgene" (E=E'= trichloromethoxy) in a suitable solvent, such as 1,2-DCE, at a suitable temperature, such as 0-40 °C, in the presence of a suitable base, such as DIPEA.

Compounds of formula V may be prepared by standard procedures known to the skilled person. This includes reduction of compounds of formula VII

wherein R1-R3 and PG are as defined above.

The reduction of compounds of formula VII may be accomplished using standard procedures known to the skilled person. This includes reaction with hydrogen gas in the presence of a suitable catalyst, such as Pd, on charcoal in a suitable solvent, such as ethanol. Compounds of formula VII may be prepared by standard procedures known to the skilled person. This includes:

a) Reaction of compounds of formula VIII

VIII wherein R1-R3 are as defined above,

with a compound IX

IX wherein PG is a suitable protecting group, such as Boc or carbethoxy.

Compounds of formula VIII are commercially available or may be prepared according to literature procedures.

Compounds of formula IX are commercially available or may be prepared according to literature procedures.

Compounds of formula III were commercially available.

Compounds of formula X were commercially available. The invention disclosed herein is further illustrated by the following non-limiting examples.

Preparation of intermediates

Preparation of the intermediates with structure II

The intermediates with structure II were either commercially available or may be synthesized according to procedures listed below.

The following intermediates of formula II may be prepared as described in WO2007/036711 :

1 : 6-Fluoro- 1 -piperidin-4-yl- 1 ,3-dihydro-benzoimidazol-2-one

2: 6-Methoxy- 1 -piperidin-4-yl- 1 ,3-dihydro-benzoimidazol-2-one

3 : 5-Fluoro- 1 -prperidin-4-yl- 1 ,3-dihydro-benzoimidazol-2-one

Prepared starting from 2,5-difluoro nitrobenzene

¹H NMR (D₆-DMSO): 1.69 (m, 2H); 2.19 (m, 2H); 2.92 (br, 2H); 4.13 (m, 2H); 4.34 (m, IH); 6.76-6.86 (2H); 7.22 (m, IH); 11.01 (s, IH).

The following intermediate with structure II may be prepared as described in WO2007/036718:

4: 6-Chloro-5-fluoro-l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-one

4-Fluoro-l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-one 5: 4-(3-Fluoro-2-nitro-phenylamino)-piperidine-l-carboxylic acid tert-butyl ester

l,3-Difluoro-2-nitro-benzene (31 mmol) and 4-amino-l-Boc piperidine (31 mmol) were dissolved in DMF (50 mL) and K2CO3 (50 mmol) was added. The mixture was stirred at 70 °C for 6h, then it was cooled and poured into brine and extracted x3 with ethyl acetate. The combined organic phases were washed x3 with brine, dried on MgSO₄, filtered and evaporated. The crude product was used without further purification. 6: 4-(2-Amino-3-fluoro-phenylamino)-piperidine-l-carboxylic acid tert-butyl ester

4-(3-Fluoro-2-nitro-phenylamino)-piperidine-l-carboxylic acid tert-butyl ester (5) (ca 31 mmol) was dissolved in EtOH (130 rnL) and 5% Pd on charcoal (1.3g) was added. The mixture was hydrogenated on a Parr-apparatus under 3 atm. H₂ at room temperature for 5h. The catalyst was removed by filtration through a silica plug and the solvent was removed by evaporation. Yield = 83% 1H NMR (CDCl₃): 1.50 (s, 9H); 2.04 (m, 2H); 2.97 (m, 2H); 3.34 (m, 2H); 4.06 (m, 2H); 6.43-6.58 (2H); 6.73 (m, IH).

7: 4-(4-Fluoro-2-oxo-2,3-dihydro-benzoimidazol-l-yl)-piperidine-l-carboxylic acid tert- butyl ester

4-(2-Amino-3-fluoro-phenylamino)-piperidine-l-carboxylic acid tert-butyl ester (6) (26 mmol) was dissolved in ethyl acetate (100 mL) and added DIPEA (57mmol). The mixture was cooled to 0°C and triphosgene (26mmol) was added portion wise. The mixture was allowed to come to ambient temperature and was stirred over night. H₂O (100 mL) was added and the solvent volume was reduced by evaporation. The aqueous phase was extracted x3 with ethyl acetate and the combined organic phases were washed with brine, dried on MgSO₄, filtered and evaporated. Yield = 89% ¹H NMR (D₆-DMSO): 1.44 (s, 9H); 1.71 (m, 2H); 2.20 (m, 2H); 2.88 (m, 2H); 4.13 (m, 2H); 4.36 (m, IH); 6.83-7.10 (3H); 11.43 (s, IH).

8 : 4-Fluoro- 1 -piperidin-4-yl- 1 ,3-dihydro-benzoimidazol-2-one

4-(4-Fluoro-2-oxo-2,3-dihydro-benzoimidazol- 1 -yl)-piperidine- 1 -carboxylic acid tert-butyl ester (7) (23 mmol) was dissolved in MeOH (180 rnL) and HCl in ether (2M) (100 rnL) was added. Stirred at room temperature for 3h. The solvent was reduced by evaporation and ice water was added (100 mL). NH3 in water (ca.l2M) was added until pH was basic. The aqueous phase was extracted with ethyl acetate x3, the organic fractions were combined, dried on MgSO₄, filtered and evaporated.

Yield ca. 100%

¹H NMR (D₆-DMSO): 1.59 (m, 2H); 2.18 (m, 2H); 2.57 (m, 2H); 3.07 (m, 2H); 2.24 (m, IH); 6.82-7.03 (2H); 7.15 (d, IH).

The following may be prepared analogously:

9: 2-Oxo-3-piperidin-4-yl-2,3-dihydro-lH-benzoimidazole-6-carbonitrile

Prepared starting from 3-fluoro-4-nitro-benzonitrile.

¹H NMR (D₆-DMSO): 1.67 (m, 2H); 2.28 (m, 2H); 2.65 (m, 2H); 3.14 (m, 2H); 4.35 (m, IH); 7.19 (d, IH); 7.51 (d, IH); 7.87 (s, IH). 10: 5-Chloro-l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-one

Prepared starting from 5-chloro-2-fluoro nitrobenzene

¹H NMR (D₆-DMSO): 1.59 (m, 2H); 2.16 (m, 2H); 2.57 (m, 2H); 3.07 (m, 2H); 4.22 (s, IH);

6.98-7.06 (2H); 7.30 (d, IH).

General procedures for the preparation of compounds with formula I

Examples:

11: 1 -(I -Cyclohexyl-piperidin-4-yl)- 1 ,3-dihydro-benzoimidazol-2-one

A solution of cyclohexanone (0.1 mmol) in 1,2-DCE (0.5 mL) and a solution of 1-piperidin- 4-yl-l,3-dihydro-benzoimidazol-2-one (0.05 mmol) in 1,2-DCE (0.5 mL) was mixed, acetic acid (10 μL) was added and the mixture was stirred for 20 min. NaBH(O Ac)₃ (0.1 mmol) was added and the reaction was shaken over night at room temperature. The reaction was quenched with methanol (200 uL) and concentrated by evaporation. The residue was dissolved in DMSO (200 uL) and purified by prep-LC-MS.

LC/MS: m/z = 300.4 (MH⁺); retention time = 0.88. 12: l-(l-Cvclopentyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one

To a mixture of cyclopentanone (0.08 mmol) and 2 (0.04 mmol) was added THF (1 rnL), acetic acid (0.44 mmol) and NaBH (OAC)₃ (0.12 mmol). The reaction mixture was shaken over night at room temperature. The reaction was quenched with methanol (200 uL) and concentrated by evaporation. The residue was dissolved in DMSO (200 uL) and purified by prep-LC-MS.LC/MS: m/z = 316.3 (MH⁺); retention time = 0.89.

The following may be prepared analogously:

13 : 1 -( 1 -Cvcloheptyl-piperidin-4-yl)-6-fluoro- 1 ,3-dihydro-benzoimidazol-2-one

Prepared from compounds 1 and cycloheptanone LC/MS: m/z = 332.2 (MH⁺); retention time = 1.06 14: 1 -[ 1 -(4-Methyl-cyclohexyl)-piperidin-4-yll- 1 ,3-dihydro-benzoimidazol-2-one

Prepared from compounds l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-one and 4-methyl- cyclohexanone.

LC/MS: m/z = 314.2 (MH⁺); retention time = 1.01.

15: β-Chloro-S-fluoro- 1-[ 1 -(3-methyl-cyclohexyl)-piperidin-4-yll- 1 ,3-dihydro- benzoimidazol-2-one

Prepared from compounds 4 and 3-methylcyclohexanone

LC/MS: m/z = 366.5 (MH⁺); retention time = 1.17.

16: l-(l-Cycloheptyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds l-piperidin-4-yl-l,3-dihydro-benzoimidazol-2-one and cycloheptanone LC/MS: m/z = 314.3 (MH⁺); retention time = 1.

17: 5-Chloro-l-(l-cvclopentyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 10 and cyclopentanone

LC/MS: m/z = 320.1 (MH⁺); retention time = 0.99.

18: l-(l-Cvcloheptyl-piperidin-4-yl)-5-fluoro-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 3 and cycloheptanone LC/MS: m/z = 332.3 (MH⁺); retention time = 1.05.

19: l-(l-Cvclopentyl-piperidin-4-yl)-4-fluoro-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 8 and cyclopentanone LC/MS: m/z = 304.3 (MH⁺); retention time = 0.87. 20: 4-Fluoro- 1-[ 1 -(4-methyl-cyclohexyl)-piperidin-4-yll- 1 ,3-dihydro-benzoimidazol-2-one

Prepared from compounds 8 and 4-methylcyclohexanone LC/MS: m/z = 332.3 (MH⁺); retention time = 1.04

21: 6-Chloro-5-fluoro-l-(l-isopropyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 4 and acetone τ+-

LC/MS: m/z = 312.5 (MH⁺); retention time = 0.97.

22: 4-Fluoro-l-(l-isopropyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 8 and acetone

LC/MS: m/z = 378.3 (MH⁺); retention time = 0.8. 23: 3-[l-(3-Methyl-cyclohexyl)-piperidin-4-yll-2-oxo-2,3-dihydro-lH-benzoimidazole-5- carbonitrile

Prepared from compounds 9 and 3-methylcyclohexanone LC/MS: m/z = 339.5 (MH⁺); retention time = 1.02.

24: 6-Chloro-l-(l-cvclobutyl-piperidin-4-yl)-5-fluoro-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 4 and cyclobutanone LC/MS: m/z = 324.4 (MH⁺); retention time = 1.0.

25: 1 -[ 1 -(4,4-Difluoro-cvclohexyl)-piperidin-4-yll-6-methoxy- 1 ,3-dihydro-benzoimidazol-2-

Prepared from compounds 2 and 4,4'-difluorocyclohexanone LC/MS: m/z = 366.6 (MH⁺); retention time = 0.97. 26: l-(l-Cvclobutyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one

Prepared from compounds 2 and cyclobutanone LC/MS: m/z = 302.5 (MH⁺); retention time = 0.84.

27: 6-Chloro- 1 -[ l-(4,4-difluoro-cyclohexyl)-piperidin-4-yll-5-fluoro- 1 ,3-dihydro- benzoimidazol-2-one

Prepared from compounds 4 and 4,4'-difluorocyclohexanone LC/MS: m/z = 388.4 (MH⁺); retention time = 1.11.

28: l-ri-(l-Ethyl-propyl)-piperidin-4-yll-6-methoxy-l,3-dihydro-benzoimidazol-2-one

3-Bromopentane (0.085 mmol) and 2 (0.042 mmol) was dissolved in N,N-dimethyl- formamide (0.2 mL). N,N-Diisopropylethylamine (25 μL) was added and the reaction was left overnight at 70 ⁰C. The compound was purified by prep-LC-MS. LC/MS: m/z = 318.4 (MH⁺); retention time = 0.94.

The following compound may be prepared analogously:

29: 6-Chloro-l-[l-(l-ethyl-propyl)-piperidin-4-yll-5-fluoro-l,3-dihydro-benzoimidazol-2- one

Prepared from compounds 4 and 3-bromopentane. LC/MS: m/z = 340.4 (MH⁺); retention time = 1.09.

Abbreviations:

DMF = JV,jV-dimethyl formamide THF = tetrahydrofuran DMSO = dimethylsulfoxide TFA = trifluoroacetic acid DIPEA= JV,JV-diisopropyWV-ethyl amine Boc = te/t-butylcarbonyloxy 1,2-DCE = 1,2-dichloroethane IBX = l.hydroxy-l,2-benziodoxol-3(lH)one-l-oxide Reagents used for the preparation of compounds 1- 29

Name CAS no. Supplier Catalog no.

4,4-difluorocyclohexanone 22515-18-0 Matrix 020185 3-Fluoro-4-nitrobenzonitrile 218632-01-0 3B-Medical 3B-2884 2-Chloro-6-fluoronitrobenzene 64182-61-2 3B-Medical 3B-3442

Pharmacological Testing:

Calcium²⁺ flux assay for human Ml-mACh receptor stably expressed in CHO-Kl cells. A. Stable cell lines.

Standard molecular cloning techniques (Maniatis et al. Molecular Cloning, A Laboratory

Manual (1989)) were used to generate a cell line of Chinese hamster ovary (CHO-Kl) cells stably expressing human muscarinic Ml receptor (Ml-mAChR). The cDNA encoding the Ml-mAChR corresponds to the sequence published in NCBI Genbank Nucleotide database, accession number Y00508. The cell line was grown in F-12 Kaighn's medium with L- Glutamine (Gibco), 10% FetalClone I serum (HyClone), 1% penicillin and streptavidine, and 0.5 μg/ml G418 (Gibco).

B. Methods CHO-Kl cells stably expressing human Ml-mAChR receptor were plated in growth medium at a density of 18.000 cells/well in clear-bottomed, cell-culture coated 96-well plates (Corning, Costar #3904) and grown for 48 hrs at 37°C in the presence of 5% CO₂. Before assay, the cells were washed with 2x100 μl of assay buffer (Hanks' balanced salt solution with Ca²⁺ and Mg²⁺(Gibco) containing 20 mM HEPES, pH 7.4. The cells were incubated with a calcium-sensitive fluorescent dye, Calcium assay kit R8033 (100 μl /well, half concentration relative to manufacturers instruction, Molecular Devices Inc) with 2.5 mM Probenecid (Sigma) for 50 minutes at 37°C and followed by 10 min at room temperature. Calcium flux was measured using a CellLux Cellular Fluorescence Workstation, a fluorometric plate reader (PerkinElmer Inc). The cells are excited by 480 nm light and emitted fluorescent light passed through an emission filter and detected by a CCD camera. The CellLux apparatus allows multiple liquid additions by computer-controlled liquid- handling hardware. Test compounds were diluted from 2 mM stock solutions in 100% DMSO in assay buffer, and then added to cells (25 μl to 100 μl in well). 10 different concentrations were tested for each compound. Fluorescence readout was measured for 5 minutes starting just prior to compound addition.

C. Data analysis

The fluorescence readout was calculated as max-min response, i.e. maximum fluorescence reading after and before liquid addition. The fluorescence max-min data were normalized to yield responses for no stimulation (buffer) and full stimulation (1 μM acetylcholine) of 0% and 100% stimulation, respectively. Data were collected from at least three independent experiments. Concentration-response data were fitted to the four-parameter logistic equation to estimate compound potency (EC50) and efficacy (E_max) (Motulsky and Christopoulos, 2004).

Harvey Motulsky, Arthur Christopoulos, Fitting Models to Biological Data Using Linear and Nonlinear Regression (A Practical Guide to Curve Fitting), ISBN: 0195171802, Oxford University, 2004.

Results of the experiments showed that the majority of the compounds of the invention had EC50 values of <50nM, many compounds <20nM and some had EC50 values <10nM.

The majority of the tested compounds furthermore afforded E_max stimulation values of >80%, many even >95%.

Claims

1. A Compound of Formula I

wherein

Rl and R3 are idenpendently selected from H, cyano, halogen, such as F or Cl, Ci_6 alkoxy, such as methoxy, or Ci_6 alkyl, such as methyl

R2 is selected from H and halogen, such as F or Cl;

Z is selected from hydrogen, Ci_3 alkyl and halogen, such as F or Cl;

and enantiomers, diastereomers, tautomers and pharmaceutically acceptable acid addition salts thereof, and polymorphic forms thereof, provided that the compound is not l-[l-(4- Propyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydrobenzoimidazol-2-one.

2. The compound according to claim 1, in which Y and Y' are identical

3. The compound according to claim 1, in which Y and Y', together with the carbon atom to which they are attached, form a C3_7 cycloalkyl group which is substituted with one or two substituents Z selected from hydrogen, Ci_3 alkyl and halogen.

4. The compound according to claim 3, in which the substituted C3_7 cycloalkyl group is 3- methylcyclohexyl

5. The compound according to claim 3, in which the substituted C3-7 cycloalkyl group is A- methylcyclohexyl

6. The compound according to claim 3, in which the substituted C3-7 cycloalkyl group is 4,4-difluorocyclohexyl

7. The compound according to claim 1, in which Y and Y', together with the carbon atom to which they are attached, form a cyclobutyl group

8. The compound according to claim 1, in which Y and Y', together with the carbon atom to which they are attached, form a cyclopentyl group

9. The compound according to claim 1, in which Y and Y', together with the carbon atom to which they are attached, form a cyclohexyl group

10. The compound according to claim 1, in which Y and Y', together with the carbon atom to which they are attached, form a cycloheptyl group

11. The compound according to any one of claims 1-10, wherein Rl, R2 and R3 are all hydrogen.

12. The compound according to any one of claims 1-10, wherein at least one of Rl, R2 and R3 is not hydrogen.

13. The compound according to any one of the claims 1-10, wherein at least one of Rl, R2 and R3 is halogen, such as F and Cl.

14. The compound according to any one of the claims 1-10, wherein Rl is halogen, such as F and Cl.

15. The compound according to any one of the claims 1-10 , wherein R2 is halogen, such as F and Cl.

16. The compound according to any one of the claims 1-10, wherein R3 is halogen, such as F and Cl.

17. The compound according to any one of claims 1-10, wherein R3 is Ci_6 alkoxy, such as methoxy.

18. The compound according to any one of claims 1-10, wherein R3 is cyano.

19. The compound according to any one of claims 1-10, wherein R2 and R3 are both halogen, such as F and Cl.

20. The compound according to any one of the preceding claims wherein at least one of Rl, R2 and R3 is hydrogen.

21. The compound according to claim 1, wherein the compound is selected from: l-(l-Cyclopentyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one l-(l-Cycloheptyl-piperidin-4-yl)-6-fluoro-l,3-dihydro-benzoimidazol-2-one 1 -[ 1 -(4-Methyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydro-benzoimidazol-2-one

6-Chloro-5-fluoro- 1-[ 1 -(3-methyl-cyclohexyl)-piperidin-4-yl]- 1 ,3-dihydro- benzoimidazol-2-one l-(l-Cyclohexyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one 1 -(I -Cycloheptyl-piperidin-4-yl)- 1 ,3-dihydro-benzoimidazol-2-one

4-Fluoro-l-(l-isopropyl-piperidin-4-yl)-l,3-dihydro-benzoimidazol-2-one

3-[l-(3-Methyl-cyclohexyl)-piperidin-4-yl]-2-oxo-2,3-dihydro-lH-benzoimidazole-5- carbonitrile l-(l-Cyclobutyl-piperidin-4-yl)-6-methoxy-l,3-dihydro-benzoimidazol-2-one

6-Chloro-l-(l-cyclobutyl-piperidin-4-yl)-5-fluoro-l,3-dihydro-benzoimidazol-2-one l-[l-(l-Ethyl-propyl)-piperidin-4-yl]-6-methoxy-l,3-dihydro-benzoimidazol-2-one 6-Chloro- 1 -[ 1 -(l-ethyl-propyl)-piperidin-4-yl]-5-fluoro- 1 ,3-dihydro-benzoimidazol-2- one 1 -[ 1 -(4,4-Difluoro-cyclohexyl)-piperidin-4-yl]-6-methoxy- 1 ,3-dihydro-benzoimidazol-2- one

or a pharmaceutically acceptable acid addition salt thereof.

22. A compound according to any one of claims 1 to 21 as a medicament.

23. A compound according to any one of claims 1 to 21 but without proviso, alone or in combination with one or more neuroleptic agents, for use in the treatment of schizophrenia.

24. A compound according to any one of claims 1 to 21 but without proviso, for use in the treatment of cognitive impairment such as mild cognitive impairment and cognitive impairment associated with schizophrenia.

25. A compound according to any one of claims 1 to 21 but without proviso, for use in the treatment of cognitive impairment associated with a psychiatric disorder such as schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type; affective disorders such as depression or anxiety, sleep disturbances, migraine, neuroleptic-induced parkinsonism, abuse disorders such as cocaine abuse, nicotine abuse, and alcohol abuse, bipolar disorder, delusional disorder; substance-induced psychotic disorder, for example psychosis induced by alcohol, amphetamine, cannabis, cocaine, hallucinogens, inhalants, opioids, or phencyclidine; personality disorder of the paranoid type; and personality disorder of the schizoid type; and anxiety disorder selected from panic disorder; agoraphobia; a specific phobia; social phobia; obsessive-compulsive disorder; post-traumatic stress disorder; acute stress disorder; and generalized anxiety disorder.

26. A compound according to any one of claims 1 to 21 but without proviso, for use in the treatment of cognitive impairment associated with a cognition disorder such as Alzheimer's disease, multi-infarct dementia, alcoholic dementia or other drug-related dementia, dementia associated with intracranial tumors or cerebral trauma, dementia associated with Huntington's disease or Parkinson's disease, or AIDS-related dementia; attention deficits, delirium; amnestic disorder; post-traumatic stress disorder; mental retardation; a learning disorder, for example reading disorder, mathematics disorder, or a disorder of written expression; attention-deficit/hyperactivity disorder (ADHD); and memory impairment such as age associated memory impairment.

27. Use of a compound according to any one of claims 1 to 21 but without proviso, for the manufacture of a medicament for the treatment of schizophrenia.

28. Use of a compound according to any one of claims 1 to 21 but without proviso, or a pharmaceutically acceptable acid addition salt thereof, for the manufacture of a medicament for the treatment of cognitive impairment such as mild cognitive impairment and cognitive impairment associated with schizophrenia.

29. Use of a compound according to any one of claims 1 to 21 but without proviso, for the manufacture of a medicament for the treatment of cognitive impairment associated with a condition or disease selected from the group consisting of a psychiatric disorder such as schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type; affective disorders such as depression or anxiety, sleep disturbances, migraine, neuroleptic-induced parkinsonism, abuse disorders such as cocaine abuse, nicotine abuse, and alcohol abuse, bipolar disorder, delusional disorder; substance-induced psychotic disorder, for example psychosis induced by alcohol, amphetamine, cannabis, cocaine, hallucinogens, inhalants, opioids, or phencyclidine; personality disorder of the paranoid type; and personality disorder of the schizoid type; and anxiety disorder selected from panic disorder; agoraphobia; a specific phobia; social phobia; obsessive-compulsive disorder; post-traumatic stress disorder; acute stress disorder; and generalized anxiety disorder.

30. Use of a compound according to any one of claims 1 to 21 but without proviso, for the manufacture of a medicament for the treatment of cognitive impairment associated with a condition or disease selected from the group consisting of a cognition disorder such as Alzheimer's disease, multi-infarct dementia, alcoholic dementia or other drug-related dementia, dementia associated with intracranial tumors or cerebral trauma, dementia associated with Huntington's disease or Parkinson's disease, or AIDS-related dementia; attention deficits, delirium; amnestic disorder; post-traumatic stress disorder; mental retardation; a learning disorder, for example reading disorder, mathematics disorder, or a disorder of written expression; attention-deficit/hyperactivity disorder (ADHD); and memory impairment such as age associated memory impairment.

31. A method of treating a mammal suffering from schizophrenia, comprising administering a therapeutically effective amount of a compound according to any one of claims 1 to 21, but without proviso.

32. The method according to Claim 31 wherein the compound of formula I is coadministered with a neuroleptic agent such as sertindole, olanzapine, risperidone, quetiapine, aripiprazole, haloperidol, clozapine, ziprasidone and osanetant.

33. A method of treating a mammal suffering from cognitive impairment, such as mild cognitive impairment and cognitive impairment associated with schizophrenia, which method comprises administering an effective amount of a compound according to any one of claims 1 to 21, but without proviso.

34. A method of treating a mammal suffering from cognitive impairment associated with a condition or disease selected from the group consisting of a psychiatric disorder such as schizophrenia, for example of the paranoid, disorganized, catatonic, undifferentiated, or residual type; schizophreniform disorder; schizoaffective disorder, for example of the delusional type or the depressive type; affective disorders such as depression or anxiety, sleep disturbances, migraine, neuroleptic-induced parkinsonism, abuse disorders such as cocaine abuse, nicotine abuse, and alcohol abuse, bipolar disorder, delusional disorder; substance-induced psychotic disorder, for example psychosis induced by alcohol, amphetamine, cannabis, cocaine, hallucinogens, inhalants, opioids, or phencyclidine; personality disorder of the paranoid type; and personality disorder of the schizoid type; and anxiety disorder selected from panic disorder; agoraphobia; a specific phobia; social phobia; obsessive-compulsive disorder; post-traumatic stress disorder; acute stress disorder; and generalized anxiety disorder, which method comprises administering an effective amount of a compound of any one claims 1 to 21, but without proviso.

35. A method of treating a mammal suffering from cognitive impairment associated with a condition or disease selected from the group consisting of a cognition disorder such as

Alzheimer's disease, multi-infarct dementia, alcoholic dementia or other drug-related dementia, dementia associated with intracranial tumors or cerebral trauma, dementia associated with Huntington's disease or Parkinson's disease, or AIDS-related dementia; attention deficits, delirium; amnestic disorder; post-traumatic stress disorder; mental retardation; a learning disorder, for example reading disorder, mathematics disorder, or a disorder of written expression; attention-deficit/hyperactivity disorder (ADHD); and memory impairment such as age associated memory impairment, which method comprises administering an effective amount of a compound according to any one of claims 1 to 21, but without proviso.

36. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to any one of claims 1 to 21 and one or more pharmaceutically acceptable carriers, diluents and excipients.