EP0836604A1

EP0836604A1 - Novel substituted azabicyclic compounds

Info

Publication number: EP0836604A1
Application number: EP96921918A
Authority: EP
Inventors: Preben H. Olesen; John Bondo Hansen
Original assignee: Novo Nordisk AS
Current assignee: Novo Nordisk AS
Priority date: 1995-06-29
Filing date: 1996-06-28
Publication date: 1998-04-22
Also published as: WO1997001558A1; JPH11508541A; AU6299496A

Abstract

A compound of formula (I), wherein p is 1 and m is 0 and n is 1 or 2, or p is 1 and m is 1 and n is 1, or p is 2 and m is 0 and n is 1; and wherein Y is formula (a). The present invention relates to therapeutically active heterocyclic compounds (I), to methods for their preparation and to pharmaceutical compositions comprising the compounds. The novel compounds are useful in treating diseases in the central nervous system related to malfunctioning of the nicotinic cholinergic system.

Description

NOVEL SUBSTITUTED AZABICYCLIC COMPOUNDS Field of the Invention

The present invention relates to heterocyclic compounds which are cholinergic ligands selective for neuronal nicotinic channel receptors, to methods for their preparation, to pharmaceutical compositions comprising them, and to their use in treating cognitive, neurological and mental disorders, which are characterized by decreased nicotinic cholinergic function. The invention also relates to a method of treating Parkinson's disease by modulating the process of dopamine secretion, a method of treating or preventing withdrawal symptom^'s caused by cessation of chronic or long term use of tobacco products, as well as a method for treating obesity.

Background of the Invention

Nicotinic and muscarinic receptors are the two distinct types of choliner¬ gic receptors named after their selectivity for muscarine and nicotine, respectively. The cholinergic system is the neurotransmitter system that best correlates with memory and cognitive functions. Traditionally, the cholinergic hypothesis for senile dementia of the Alzheimer type (SDAT) has focused on muscarinic acetylcholine receptors (mAChR), and only recently an interest in the role of the nicotinic acetylcholine receptors (nAChR) in SDAT has emerged. This interest was spurred by the rela- tively recent discovery that nAChR are not only located on the skeletal muscle but also in the brain.

It has been shown that the number of nAChR were decreased in SDAT patients (Nordberg et al., J. Neurosci. Res. Vol. 31 , pp. 1 03-1 1 1 (1 992); Giacobini, Advances in Experimental Medicine and Biology, Vol. 296, pp.9205-9295, (1 993); Schroeder et al., Neurobiol. of Aging, Vol. 1 2, pp. 259-262, (1 991 ); Whitehouse et al., Neurology, Vol. 38, pp. 720- 723, ( 1 988); Flynn and Mash, J. Neurochem., Vol. 47, pp. 8702-8702, (1 993)). Similar deficiencies in choline acetyltransferase activity and acetylcholine synthesis suggest that presynaptic receptors on cholinergic nerve terminals are preferentially lost in SDAT (Nordberg, J. Reprod. Fert. Suppl., Vol 46, pp. 145-1 54, ( 1 993)). Therefore, it has been assumed that the loss of nAChR may correlate with age related onset of disorders of memory and cognitive functions, and that nicotinic replacement therapy may prove beneficial in SDAT. Indeed nicotine improved attention and memory in healthy humans (Warburton, Prog. Neuro. Psychopharma¬ col. Biol., Psychiatry, Vol. 1 6, pp. 1 81 -1 91 , . (1 992)) as well as in Alz- heimer's disease patients, (Jones et al., Psychopharmacology, Vol. 1 08, pp. 485-494, (1 992); Gitelman and Prohovnik, Neurobiol. of Aging, Vol. 1 3, pp. 31 3-31 8, (1 992); Newhouse et al., Psychopharmacology, Vol. 95, pp. 1 71 -1 75, (1 988); Sahakian et al., Br. J. Psychiatry, Vol.1 54, pp. 9004-904, (1 993)). Further the nicotinic antagonist mecamylamine has been shown to cause cognitive impairment in an age related way, (Newhouse et al., Neuropsychopharmacology, Vol 1 0, pp. 93-107, ( 1 994)).

Parkinson's disease (PD) is a debilitating neurodegenerative disease, presently of unknown etiology, characterized by tremors and muscular rigidity. There is evidence that nicotine may also have beneficial effects in PD. Studies show that smoking may protect against the development of PD, (Ishikawa and Mmiyatake, J. Neurol. Sci., Vol. 1 1 7, pp. 28-32, (1 993); Godwin-Austen et al., J. Neurol. Neurosurg. Psychiat., Vol. 45, pp. 577-581 , (1 982); Reavill, in Nicotine psychopharmacology: Molecu¬ lar, cellular and behavioral aspects, pp. 307-340, Oxford University Press, (1 990)), and that chronic nicotine may protect against cell loss in the substantia nigra caused by lesioning (Janson and Moller, Neuro¬ science, Vol. 57, 931 -941 , (1 993)). Nicotine has also shown beneficial effects in Tourette's syndrome (Sanberg et al., Biomed. Phamacother., Vol. 43, pp. 1 9-23, (1 989)). Alleviation of negative psychotic symptoms, known as the hypofrontality syndrome in schizophrenia, by nicotinic agonists, have been suggested by data showing that nicotine stimulates dopamine release in the nucleus accumbens more potently than in stria¬ tum, (Rowell et al. J. Neurochem., Vol. 49, pp. 1 449-1 454, (1 987); Giorguieff-Chesselet et al., Life Sciences, Vol. 25, pp. 1 257-1 262, ( 1 979)), by nicotinic reversal of inactivation of prefrontal neurons (Sven- son et al., In the Biology of Nicotine dependence., pp. 1 69-1 85, New York, (1 990)), and by the observation that nicotine will potentiate dopa¬ minergic effects in various behavioral models, (Reavill, in Nicotine psy¬ chopharmacology: Molecular, cellular and behavioral aspects, pp. 307- 340, Oxford University Press, ( 1 990); Rosecrans et al., Psychophar¬ macol. Commmun., Vol. 2, pp. 349-356, (1 976); Reavill and Stolerman, J. Psychopharmacol., Vol. 1 , pp. 264, (1 987)).

In recent years there have been several studies on the effects of nicotine and food consumption and associated changes in body weight in rat and human. (Greenberg et al., Addictive behaviours, Vol. 7, pp. 31 7-331 , ( 1 982) and Greenberg et al., Psychopharmacology, Vol. 90, pp. 1 01 - 105, (1 984)). The appetite effects of nicotine have been suggested to be mediated via modulation of CCK peptides in the paraventricular hypotha- lamic nucleus (Fuxe et al., Acta Physiologica Scandinavica, Vol. 1 25, pp. 437-443, (1 985)).

EP 414394 discloses a class of methyleneazabicyclic compounds, substi¬ tuted with a five membered heterocyclic ring described as cholinergic compounds which enhance acetylcholine function via an action at mus¬ carinic receptors within the central nervous system.

Description of the invention

It is an object of the invention to provide compounds with affinity and selectivity for nicotinic cholinergic receptors, to methods for their prepa¬ ration, to pharmaceutical compositions containing them, and to their use in treating Alzheimer's disease, Parkinson's disease, Tourette's syn¬ drome, ulcerative colitis, obesity, other central nervous system and gastrointestinal disorders, severe pain as well as withdrawal symptoms caused by cessation of chronic or long term use of tobacco products.

The present invention relates to novel substituted azabicyclic compounds of formula I

wherein p is 1 and m is 0 and n is 1 or 2, or p is 1 and m is 1 and n is 1 , or p is 2 and m is 0 and n is 1 ; and wherein Y is

wherein -A-B-C-D- is selected from

= C(R )-O-N = C(R²)-, = C(R¹)-S-N = C(R²)-, = C(R¹)-N = C(R²)-O-, = C(R¹)-C(R²) = C(R³)-O-, = C(R¹)-C(R²) = N-O-, = C(R¹)-N = C(R²)-S-,

= C(R¹)-C(R²) = C(R³)-S-, = C(R¹)-C(R²) = N-S-, -C(R¹) = C(R²)-O-C(R³) = , -C(R¹) = C(R²)-S-C(R³) = , -N(R⁴)-N = C(R¹)-C(R²) = , = N-N(R⁴)-C(R¹) = C(R²)-, = N-O-C(R¹) = C(R²)-, = N-S-C(R¹) = C(R²)-, -N(R⁴)-C(R¹) = N-C(R²) = , -N = C(R¹)-N(R⁴)-C(R²) = , = C(R¹)-N(R⁴)-N = C(R²)-, -N = C(R¹)-O-C(R²) = , -N = C(R¹)-S-C(R²) = , = N-C(R¹) = C(R²)-N(R⁴)-, = N-C(R¹) = C(R²)-O-, = N-C(R¹) = C(R²)-S-, -N(R⁴)-N = N-C(R¹) = , = N-N(R⁴)-N = C(R¹)-, -N = N-N(R⁴)-C(R¹) = , -N(R⁴)-N = C(R¹)-N = , = N-N(R )-C(R ) = N-, = N-N = C(R¹)-N(R⁴)-, = N-O-N = C(R¹)-, = N-N = C(R¹)-O-, -N = C(R¹)-O-N = , = N-C(R¹) = N-O-, = N-N = C(R¹)-S-, = N-S-N ^*= C(R¹)-, = N-C(R¹) =. N-S-, -N = C(R¹)-S-N = , -N(R⁴)-N = N-N = , = N-N(R⁴)-N = N-; and

R\ R² and R³ independently are -NO₂, -CN, -NR⁵R⁶, -OR⁷, -SR⁸, -COOR⁹, -SOR¹⁰, -SO₂R" , -SO₃R¹², C₃.₆-alkyl, C₄.₆-alkenyl, C₄.₆-alkynyl, C₃.₆-cyclo- alkyl, -R¹³-O-R¹⁴ or -R^{l 5}-S-R¹⁶, and R⁴ is C₃.₆-alkyl, C₂.₆-alkenyl, C₄.₆-alky- nyl, C₄.₆-cycloalkyl, -R¹⁷-O-R¹⁸ or -R¹⁹-S-R²⁰, wherein R⁵ is H, C^-alkyl, C₂. ₆-alkenyl or C₂.₆-alkynyl and wherein R⁶ is C₂.₆-alkyl, C₂.₆-alkenyl or C₂.₆- alkynyl and wherein R⁷, R⁸, R⁹, R¹⁰, R¹ , R ², R¹⁴, R¹⁶, R¹⁸ and R²⁰ inde¬ pendently are hydrogen, C^-alkyl, C₂.₆-alkenyl, C₂.₆-alkynyl or C₃.₇- cycloalkyl and wherein R¹³, R¹⁵, R¹⁷ and R¹⁹ independently are C^e-alkylene, C₂.₆-alkenylene or C₂.₆-alkynylene; or a pharmaceutically acceptable salt thereof.

In a preferred embodiment of the invention -A-B-C-D- is selected from

= C(R¹)-C(R²) = N-O-, = C(R¹)-C(R²) = N-S-, = N-O-C(R¹) = C(R²)-, = N-S-C(R¹) = C(R²)-,

since these compounds have a preferred selectivity for nicotinic receptors as compared to muscarinic receptors.

In an even more preferred embodiment of the invention -A-B-C-D- is selected from = C(R¹)-C(R²) = N-O- and = C(R¹)-C(R²) = N-S-.

Examples of pharmaceutically acceptable salts include inorganic and organic acid addition salts such as hydrochloride, hydrobromide, sul¬ phate, phosphate, acetate, fumarate, maleate, citrate, lactate, tartrate, oxalate, or similar pharmaceutically-acceptable inorganic or organic acid addition salts, and include the pharmaceutically acceptable salts listed in Journal of Pharmaceutical Science, 66, 2 .(1977) which are hereby incorporated by reference.

The compounds of formula I may exist as geometric and optical isomers and all isomers and mixtures thereof are included herein. Isomers may be separated by means of standard methods such as chromatographic techniques or fractional crystallization of suitable salts.

Alkyl, alkenyl and alkynyl as used herein refers to straight or branched alkyl, alkenyl or alkynyl chains.

The invention also relates to methods of preparing the above mentioned compounds of formula I. These methods comprise:

a) reacting a compound of formula II

(ID wherein m, n and p have the meanings defined above with a phosphorus ylide of formula III or a phosphonate of formula IV

IV

wherein R⁹, R¹⁰ and R¹¹ independently are C^-alkyl, aryl or aralkyl and

-A-B-C-D- has the meaning defined above, to give a compound of formula I; or

b) reacting a compound of formula II with a compound of formula V

wherein -A-B-C-D- has the meaning defined above, followed by a dehy¬ dration to give a compound of formula I; or

c) reacting a compound of formula II with a compound of formula VI

OR8 wherein R\ R⁷ and R⁸ have the meanings defined above, to give a com¬ pound of formula Vll

which is reacted with dimethylformamide dimethylacetale followed by a cyclization with hydroxylamine to give a compound of formula NX

The pharmacological properties of the compounds of the invention can be illustrated by determining their capability to inhibit the specific binding of ³H-methylcarbamylcholine (³H-MCC) (Abood and Grassi, Biochem. Phar¬ macol., Vol. 35, pp. 41 99-4202, (1 986)).

³H-MCC labels the nicotinic receptors in the CNS. The inhibitory effect on ³H-MCC binding reflects the affinity for nicotinic acetylcholine receptors.

Fresh or frozen rat, brain tissue (hippocampus or cortex) was homoge- nized in assay buffer (50mM Tris-HCI, pH 7.4, 1 20 mM NaCI, 5 mM KCI,

2 mM CaCI₂, 1 mM MgCI₂) and centrifuged for 1 0 min. at 40.000 x g.

Pellets were subsequently reconstituted in assay buffer and an appropri- ate amount of tissue sample was mixed in tubes with ³H-methylcarba- mylcholine (NEN, NET-951 ; final concentration 2 nM) and test drug. The tubes were incubated at 0 °C for 60 min. Unbound ligand was separated from bound ligand by vacuum filtration through GF/B filters presoaked in 0.5 % polyethylenimine. Filters were washed three times with 5 ml wash buffer (50mM Tris-HCI, pH 7.4) and transferred to vials. 4 ml scintillation fluid was added and the radioactivity was measured by scintillation counting. Unspecific binding was measured with 10 μM nicotine.

The IC₅₀ values of the test compounds were determined by nonlinear regression analyses (GraphPad InPlot).

Furthermore, the pharmacological properties of the compounds of the invention can also be illustrated by determining their capability to inhibit the specific binding of ³H-Oxotremorine-M (³H-Oxo). Birdsdall N.J.M., Hulme E.C, and Burgen A. S.V. (1 980). "The Character of Muscarinic Receptors in Different Regions of the Rat Brain" . Proc. Roy. Soc. London (Series B) 207, 1 .

³H-Oxo labels muscarinic receptor in the CNS (with a preference for agonist domains of the receptors). Three different sites are labelled by ³H- Oxo. These sites have affinity of 1 .8, 20 and 3000 nM, respectively. Using the present experimental conditions only the high and medium affinity sites are determined.

The inhibitory effects of compounds on ³H-Oxo binding reflects the affinity for muscarinic acetylcholine receptors.

All preparations are performed at 0-4°C unless otherwise indicated. Fresh cortex (0.1 -1 g) from male Wistar rats (1 50-250 g) is homogenized for 5-

1 0 s in 1 0 ml 20 mM Hepes pH: 7.4, with an Ultra-Turrax homogenizer.

The homogenizer is rinsed with 1 0 ml of buffer and the combined sus- pension centrifuged for 15 min. at 40,000 x g. The pellet is washed three times with buffer. In each step the pellet is homogenized as before in 2 x 10 ml of buffer and centrifuged for 10 min. at 40,000 x g.

The final pellet is homogenized in 20 mM Hepes pH: 7.4 (100 ml per g of original tissue) and used for binding assay. Aliquots of 0.5 ml is added 25 ul of test solution and 25 ul of ³H-Oxotremorine (1 .0 nM, final concentra¬ tion) mixed and incubated for 30 min. at 25°C. Non-specific binding is determined in triplicate using arecoline (1 ug/ml, final concentration) as the test substance. After incubation samples are added 5 ml of ice-cold buffer and poured directly onto Whatman GF/C glass fiber filters under suction and immediately washed 2 times with 5 ml of ice-cold buffer. The amount of radioactivity on the filters are determined by conventional liquid scintillation counting. Specific binding is total binding minus non specific binding.

Test substances are dissolved in 10 ml water (if necessary heated on a steam-bath for less than 5 min.) at a concentration of 2.2 mg/ml. 25- 75% inhibition of specific binding must be obtained before calculation of IC₅₀. The test value will be given as IC₅₀ (the concentration (nM) of the test substance which inhibits the specific binding of ³H-Oxo by 50%).

IC₅₀ = (applied test substance concentration) x(C_x/C₀-C_x)nM

where C₀ is specific binding in control assays and C_x is the specific binding in the test assay. (The calculations assume normal mass-action kinetics).

Table I illustrates the affinity of the compounds of the present invention for nicotinic and muscarinic receptors as determined by ³H-MCC and ³H-

Oxo binding to rat cortical receptors. The compounds, however, show selective affinity for nicotinic receptors as compared to muscarinic receptors, i.e OXO/MCC > 1

Table 1

Compound ³H-MCC ³H-Oxo Oxo/MCC ιc₅₀ IC₅₀ Ratio nM nM

1 140 1400 10

3 470 34000 72

7 580 10000 17

The compounds of the invention are effective over a wide dosage range. For example, in the treatment of adult humans, dosages from about 0.05 to about 1 00 mg, preferably from about 0.1 to about 1 00 mg, per day may be used. A most preferable dosage is about 1 0 mg to about 70 mg per day. In choosing a regimen for patients suffering from diseases in the central nervous system caused by malfunctioning of the nicotinic cholin¬ ergic system it may frequently be necessary to begin with a dosage of from about 30 to about 70 mg per day and when the condition is under control to reduce the dosage as low as from about 1 to about 1 0 mg per day. The exact dosage will depend upon the mode of administration, form in which administered, the subject to be treated and the body weight of the subject to be treated, and the preference and experience of the physician or veterinarian in charge.

The route of administration may be any route, which effectively trans¬ ports the active compound to the appropriate or desired site of action, such as oral or parenteral e.g. rectal, transdermal, subcutaneous, intra¬ venous, intraurethral, intramuscular, topical, intranasal, ophthalmic solution or an ointment, the oral route being preferred.

Typical compositions include a compound of formula I or a pharmaceuti- cally acceptable acid addition salt thereof, associated with a pharmaceuti¬ cally acceptable carrier. In making the compositions, conventional tech¬ niques for the preparation of pharmaceutical compositions may be used. For example, the active compound will usually be mixed with a carrier, or diluted by a carrier, or enclosed within a carrier which may be in the form of a ampoule, capsule, sachet, paper, or other container. When the carrier serves as a diluent, it may be solid, semi-solid, or liquid material which acts as a vehicle, excipient, or medium for the active compound. The active compound can be adsorbed on a granular solid container for example in a sachet. Some examples of suitable carriers are water, salt solutions, alcohols, polyethylene glycols, polyhydroxyethoxylated castor oil, gelatine, lactose, amylose, magnesium stearate, talc, silicic acid, fatty acid monoglycerides and diglycerides, pentaerythritol fatty acid esters, hydroxymethylcellulose and polyvinylpyrrolidone.

The pharmaceutical preparations can be sterilized and mixed, if desired, with auxiliary agents, emulsifiers, salt for influencing osmotic pressure, buffers and/or coloring substances and the like, which do not deleteri¬ ously react with the active compounds.

For parenteral application, particularly suitable are injectable solutions or suspensions, preferably aqueous solutions with the active compound dissolved in polyhydroxylated castor oil.

Tablets, dragees, or capsules having talc and/or a carbohydrate carrier or binder or the like are particularly suitable for oral application. Preferable carriers for tablets, dragees, or capsules include lactose, corn starch, and/or potato starch. A syrup or elixir can be used in cases where a sweetened vehicle can be employed.

Generally, the compounds are dispensed in unit form comprising from about 1 to about 100 mg in a pharmaceutically acceptable carrier per unit dosage.

A typical tablet, appropriate for use in this method, may be prepared by conventional tabletting techniques and contains:

Active compound 5.0 mg

Lactosum 67.8 mg Ph.Eur.

Avicel^® 31 .4 mg

Amberiite^® 1 .0 mg . Magnesii stearas 0.25 mg Ph. Eur.

The invention will now be described in further detail with reference to the following examples:

EXAMPLE 1

3-Hydroxy-3-(3-methoxymethyl-5-isoxazolyl)methyl-1 -azabicyclo[2.2.2]- octane

A solution of 3-methoxymethyl-5-methylisoxazol (2.52 g, 20 mmol) in dry tetrahydrofuran (5 ml) was added to a solution of LDA (22.5 mmol) in dry tetrahydrofuran (30 ml) cooled to -78°C. The reaction mixture was stirred at -78°C for 1 5 min. A solution of quinuclidinone (2.3 g, 20 mmol) dissolved in dry tetrahydrofuran (1 0 ml) was added. The reaction mixture was stirred for 0.5 h at -78°C, then quenched with water (100 ml) and acidified with concentrated hydrochloric acid. The water phase was extracted with ether (2 x 50 ml), then basified with solid potassium carbonate and extracted with methylene chloride (4 x 1 00 ml). The methylene chloride phases were collected and dried over magnesium sulphate. After evaporation of the solvent the title compound was iso¬ lated in 1 .4 g yield. (Z)-3-(3-Methoxymethylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]octane oxalate and (E)-3-(3-methyoxymethylisoxazol-5-yl)methylene-1 -aza- bicyclo[2.2.2]octane oxalate

To a solution of 3-hydroxy-3-(3-methyl-5-isoxazolyl)methyl-1 -azabicyclo- [2.2.2]octane (1 .4 g) in methylene chloride (30 ml) was added triethy¬ lamine (2.2 g, 25 mmol). The reaction mixture was cooled to 0°C, and thionyl chloride (2.0 g, 1 7 mmol) in methylene chloride (1 0 ml) was carefully added. The reaction mixture was stirred at 0°C for 1 h and then poured on ice. The phases were separated and the water phase made alkaline with solid potassium carbonate. The water phase was extracted with ether (4 x 100 ml). The ether phases were dried over magnesium sulphate and evaporated giving a crude mixture of Z and E isomers. The title compounds were separated by column chromatography on silica (eluent: ethyl acetate/methanol/ammonium hydroxide: 2/1 /2%). The first fractions contained the Z isomer which after crystallization with oxalic acid gave (Z)-3-(3-methoxymethylisoxazol-5-yl)methylene-1 -azabicyclo- [2.2.2]octane oxalate in 25% yield. M.p. 1 39-140°C. (Compound 1 ). The next fractions contained the E isomer which after crystallization with oxalic acid gave (E)-3-(3-methoxymethyiisoxazol-5-yi)methylene-1 -azabi- cyclo[2.2.2]octane oxalate in 28% yield. M.p. 1 62-1 63°C. (Compound 2). EXAMPLE 2

The following compounds were prepared in exactly the same manner as described in example 1 :

(Z)-6-(3-isopropyl-5-isoxazolyl)methylene-1 -azabicyclo[2.2.2]octane oxalate, starting from 1 -azabicyclo[2.2.2]octan-3-one and 3-isopropyl-5- methylisoxazole. M.p. 145-147°C. (Compound 3).

(E)-6-(3-isopropyl-5-isoxazolyl)methylene-1 -azabicyclo[2.2.2]octane oxalate, starting from 1 -azabicyclo[2.2.2]octan-3-one and 3-isopropyl-5- methylisoxazole. M.p. 1 30-1 33°C. (Compound 4).

EXAMPLE 3

(Z)-3-(3-propylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]octane oxalate and (E)-3-(3-propylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]octane oxalate

To a solution of 3-propyl-5-methylisoxazol (1 .31 g, 1 0 mmol) in dry tetrahydrofuran (30 ml) cooled to -78°C was added n-BuLi (2.5 M in hexane, 1 2.5 mmol). The reaction mixture was stirred at -78°C for 20 min. A solution of quinuclidinone (0.92 g, 8.0 mmol) dissolved in dry tetrahydrofuran (5 ml) was added. The reaction mixture was stirred for 0.5 h at -78°C. Triethylamine (2.25 g, 25 mmol) and thionyl chloride (4.0 g, 34 mmol) was added and the reaction mixture slowly heated to room temperature. The reaction mixture was quenched with water ( 1 00 ml) and acidified with concentrated hydrochloric acid. The water phase was extracted with ether (2 x 50 ml), then made alkaline with solid potassium carbonate and extracted with ether (4 x 100 ml). The ether phases were dried over magnesium sulphate and evaporated giving a crude mixture of Z and E isomers. The title compounds were separated by column chro- matography on silica (eluent: ethyl acetate/methanol/ammonium hydrox¬ ide: 2/1 /2%). The first fractions contained the Z isomer which after crystallization with oxalic acid gave (Z)-3-(3-propylisoxazol-5- yl)methylene-1 -azabicyclo[2.2.2]octane oxalate in 7% yield. M.p. 106- 108°C. (Compound 5).

The next fractions contained the E isomer which after crystallization with oxalic acid gave (E)-3-(3-propylisoxazol-5-yl)methylene-1 -azabicyclo- [2.2.2]octane oxalate in 22% yield. M.p. 1 13-.1 1 5°C. (Compound 6).

In exactly the same manner the following compound was made:

3-(3-propylisoxazol-5-yl)methylene -1 -azabicyclo[2.2.1 jheptane oxalate from 1 -azabicyclo[2.2.1 ]heptan-3-one and 3-propyl-5-methylisoxazole. M.p. 78-80°C. (Compound 7).

Claims

A compound of formula I

wherein -A-B-C-D- is selected from

= C(R¹)-O-N = C(R²)-, = C(R )-S-N = C(R²)-, = C(R¹)-N = C(R²)-O-, = C(R¹)-C(R²) = C(R³)-O-, = C(R¹)-C(R²) =N-O-, =C(R¹)-N = C(R²)-S-,

= C(R¹)-C(R²) = C(R³)-S-, = C(R¹)-C(R²) = N-S-, -C(R¹) = C(R²)-O-C(R³) = ,

-C(R¹) = C(R²)-S-C(R³) = , -N(R⁴)-N = C(R¹)-C(R²) = ,

= N-N(R⁴)-C(R¹) = C(R²)-, = N-O-C(R¹) = C(R²)-, = N-S-C(R¹) = C(R²)-,

-N(R⁴)-C(R¹) = N-C(R²) = , -N = C(R¹)-N(R⁴)-C(R²) = , = C(R¹)-N(R⁴)-N = C(R²)-, -N = C(R¹)-O-C(R²) = , -N = C(R¹)-S-C(R²) = ,

= N-C(R¹) = C(R²)-N(R⁴)-, = N-C(R¹) = C(R²)-O-, = N-C(R¹) = C(R²)-S-,

-N(R⁴)-N = N-C(R¹) = , = N-N(R⁴)-N = C(R¹)-, -N = N-N(R⁴)-C(R¹) = , -N(R⁴)-N = C(R¹)-N = , = N-N(R⁴)-C(R¹) = N-, = N-N = C(R¹)-N(R⁴)-, = N-O-N = C(R¹)-, = N-N = C(R¹)-O-, -N = C(R¹)-O-N = , = N-C(R¹) = N-O-, = N-N = C(R¹)-S-, = N-S-N = C(R¹)-, = N-C(R¹) = N-S-, -N = C(R¹)-S-N = , -N(R⁴)-N = N-N = or = N-N(R )-N = N-; and R¹, R² and R³ independently are -NO₂, -CN, -NR⁵R⁶, -OR⁷, -SR⁸, -COOR⁹, -SOR¹⁰, -SO₂R¹¹, -SO₃R¹², C₃.₆-alkyl, C₄.₆-alkenyl, C₄.₆-alkynyl, C_3.6-cyclo- alkyl, -R¹³-O-R¹⁴ or -R¹⁵-S-R¹⁶, and R⁴ is C₃.₆-alkyl, C₂.₆-alkenyl, C_4.6-alky- nyl, C₄.₆-cycloalkyl, -R¹⁷-O-R¹⁸ or -R¹⁹-S-R²⁰, wherein R⁵ is H, C^-alkyl, C₂. ₆-alkenyl or C₂.₆-alkynyl and wherein R⁶ is C₂.₆-alkyl, C₂.₆-alkenyl or C₂.₆- alkynyl and wherein R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹⁴, R¹⁶, R¹⁸ and R²⁰ inde¬ pendently are hydrogen, C^-alkyl, C₂.₆-alkenyl, C₂.₆-alkynyl or C₃.₇- cycloalkyl and wherein R¹³, R¹⁵, R¹⁷ and R¹⁹ independently are C_1-6-alkylene, C₂.₆-alkenylene or C₂.₆-alkynylene; or a pharmaceutically acceptable salt thereof.

2 A compound according to claim 1 wherein -A-B-C-D- is selected from

= C(R¹)-C(R²) = N-O-, = C(R¹)-C(R²) = N-S-, = N-O-C(R¹) = C(R²)-,

= N-S-C(R¹) = C(R²)-, preferably =C(R¹)-C(R²) = N-O- and = C(R¹)-C(R²) = N-S-, wherein R¹ and R² have the meanings defined above.

3 A compound according to claim 1 , wherein the compound is selected from the following:

(Z)-3-(3-Methoxymethylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]- octane,

(E)-3-(3-Methoxymethylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]- octane, (Z)-6-(3-lsopropyl-5-isoxazolyl)methylene-1 -azabicyclo[2.2.2]octane,

(E)-6-(3-lsopropyl-5-isoxazolyl)methylene-1 -azabicyclo[2.2.2]octane, (Z)-3-(3-Propylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]octane, (E)-3-(3-Propylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.2]octane, 3-(3-Propylisoxazol-5-yl)methylene-1 -azabicyclo[2.2.1 jheptane; or a pharmaceutically acceptable salt thereof.

4 A method of preparing a compound according to any of the preceeding claims, CHARACTERIZED IN

a) reacting a compound of formula

wherein m, n and p have the meanings defined above with a phosphorus ylide of formula III or a phosphonate of formula IV

IV

wherein R⁹, R¹⁰ and R¹¹ independently are C^-alkyl, aryl or aralkyl and -A-B-C-D- has the meaning defined above, to give a compound of formula I; or b) reacting a compound of formula II with a compound of formula V

wherein -A-B-C-D- has the meaning defined above, followed by a dehy- dration to give a compound of formula I; or

c) reacting a compound of formula II with a compound of formula VI

OR8

wherein R¹, R⁷ and R⁸ have the meanings defined above, to give a com¬ pound of formula Vll

wherein m, n, p and R¹ have the meanings defined above, which is reacted with dimethylformamide dimethylacetale followed by a cycliza- tion with hydroxylamine to give a compound of formula MX

wherein , n, p and R¹ have the meanings defined above.

f A pharmaceutical composition comprising as active component a compound according to any of claims claim 1 to 3 together with a pharmaceutically acceptable carrier or diluent.

iL. The pharmaceutical composition according to claim 5 in the form of an oral dosage unit or parenteral dosage unit.

JL. The pharmaceutical composition according to claim 6, wherein said dosage unit comprises from about 1 to about 100 mg of the com¬ pound according any of claims 1 to 3.

f A compound according to any of claims 1 to 3 for treating a central nervous system ailment related to malfunctioning of the nicotinic cholinergic system.

iL. A compound according to any of claims 1 to 3 for treating Alz¬ heimer's disease, Parkinson's disease, Tourette's syndrome, ulcerative colitis, obesity, gastrointestinal disorders or severe pain, preferably obesity, or for treating or preventing withdrawal symptoms caused by cessation of chronic or long term use of tobacco products, preferably obesity. 10. The use of a compound according to any of claims 1 to 3 for the preparation of a medicament for treatment of a disease in the central nervous system related to malfunctioning of the nicotinic cholinergic system.

1 1 . The use of a compound according to any of claims 1 to 3 for the preparation of a medicament for treatment of Alzheimer's disease, Parkinson's disease, Tourette's syndrome, .ulcerative colitis, obesity, gastrointestinal disorders or severe pain, preferably obesity, or for treat¬ ing or preventing withdrawal symptoms caused by cessation of chronic or long term use of tobacco products.

12. A method of treating a central nervous system ailment related to malfunctioning of the nicotinic cholinergic system in a subject in need of such treatment comprising administering to said subject an effective amount of a compound according to any of claims 1 to 3.

13. A method of treating Alzheimer's disease, Parkinson's disease, Tourette's syndrome, ulcerative colitis, obesity, gastrointestinal disorders or severe pain, preferably obesity, in a subject in need of such treatment comprising administering to said subject an effective amount of a com¬ pound according to any of claims 1 to 3.

14. A method of treating or preventing withdrawal symptoms caused by cessation of chronic or long term use of tobacco products comprising administering to a subject in need thereof an effective amount of a compound according to any of claims 1 to 3.

Our Ref: 4412-WO,LaKe