WO2007055928A1 - 5-membered ring metanicotine analogs - Google Patents

Abstract

E-metanicotine-type compounds that include a five-membered heteroaryl ring linked to an olefinic linker, such as a 4-penten-2-yl linker, which is linked to a terminal amine group, are disclosed. Patients susceptible to or suffering from conditions and disorders, can be treated by administering the compounds, pharmaceutical salts of the compounds, or pharmaceutical compositions including the compounds or their salts, to a patient in need thereof.

Description

5-MEMBERED RING METANICOTINE ANALOGS

This application claims benefit of U.S. Provisional Patent Application No. 60/733,293, filed November 3, 2005, fully incorporated herein by reference.

Field of the Invention

The present invention relates to nicotinic compounds and pharmaceutically acceptable salts thereof, as well as pharmaceutical compositions and methods for treating a wide variety of conditions and disorders associated with dysfunction of the central and autonomic nervous systems.

Background of the Invention

Nicotine has been proposed to have a number of pharmacological effects. See, for example, Pullan et al, N. Engl. J. Med. 330:811-815 (1994). Certain of those effects can be related to effects upon neurotransmitter release. Release of acetylcholine, dopamine, norepinephrine, serotonin, and glutamate upon administration of nicotine has been reported (Rowell et al, J. Neurochem. 43:1593 (1984); Rapier et al., J. Neurochem. 50:1123 (1988); Sandor et al, Brain Res. 567:313 (1991); Vizi, Br. J. Pharmacol. 47:765 (1973); Hall et al, Biochem. Pharmacol. 21:1829 (1972); Hery et al, Arch. Int. Pharmacodyn. Ther. 296:91 (1977); and Toth et al, Neurochem Res. 17:265 (1992)). Confirmatory reports and additional recent studies have included the modulation in the Central Nervous System (CNS) of glutamate, nitric oxide, GABA, takykinins, cytokines, and peptides (reviewed in Brioni et al, Adv. Pharmacol. 37:153 (1997)). In addition, nicotine reportedly potentiates the pharmacological behavior of certain pharmaceutical compositions used to treat certain disorders. See, for example, Sanberg et al, Pharmacol. Biochem. & Behavior 46:303 (1993); Harsing et al, J. Neurochem. 59:48 (1993); and Hughes, Proceedings from Intl. Symp. Nic. S40 (1994). Furthermore, the neuroprotective effects of nicotine have been proposed, see, for example, Sjak-shie et al, Brain Res. 624:295 (1993). Various other beneficial pharmacological effects have also been proposed. See, for example, Decina et al, Biol. Psychiatry 28:502 (1990); Wagner et al, Pharmacopsychiatry 21:301 (1988); Pomerleau et al, Addictive Behaviors 9:265 (1984); Onaivi et al, Life Sd. 54(3):193 (1994); Tripathi et al, J. Pharmacol. Exp. Ther. 221:91 (1982); and Hamon, Trends in Pharmacol. Res. 15:36 (1994).

Various compounds that target nAChRs have been reported as being useful for treating a wide variety of conditions and disorders. See, for example, Williams et ah, DN&P 7(4):205 (1994); Arneric et al, CNS Drug Rev. 1(1): 1 (1995); Arneric et al., Exp. Opin. Invest. Drugs 5(1):79 (1996); Bencherif et al, J. Pharmacol. Exp. Ther. 279:1413 (1996); Lippiello et al, J. Pharmacol. Exp. Ther. 279:1422 (1996); Damaj et al, J. Pharmacol. Exp. Ther. 291:390 (1999); Chiari et al, Anesthesiology 91:1447 (1999); Lavand'homme and Eisenbach, Anesthesiology 91:1455 (1999); Holladay et al, J. Med. Chem. 40(28): 4169 (1997); Bannon et al, Science 279: 77 (1998); PCT WO 94/08992; PCT WO 96/31475; PCT WO 96/40682; and U.S. Patent Nos. 5,583,140 to Bencherif et al; 5,597,919 to Dull et al; 5,604,231 to Smith et al; and 5,852,041 to Cosford et al. Nicotinic compounds are reported as being particularly useful for treating a wide variety of CNS disorders. Indeed, a wide variety of nicotinic compounds have been reported to have therapeutic properties. See, for example, Bencherif and Schmitt, Current Drug Targets: CNS and Neurological Disorders 1(4): 349-357 (2002), Levin and Rezvani, Current Drug Targets: CNS and Neurological Disorders 1(4): 423-431 (2002), O'Neill, et al, Current Drug Targets: CNS and Neurological Disorders 1(4): 399-411 (2002), U.S. Patent Nos. 5,1871,166 to Kikuchi et al, 5,672,601 to Cignarella, PCT WO 99/21834 and PCT WO 97/40049, UK Patent Application GB 2295387 and European Patent Application 297,858.

CNS disorders are a type of neurological disorder. CNS disorders can be drug- induced; can be attributed to genetic predisposition, infection or trauma; or can be of unknown etiology. CNS disorders comprise neuropsychiatric disorders, neurological diseases, and mental illnesses, and include neurodegenerative diseases, behavioral disorders, cognitive disorders, and cognitive affective disorders. There are several CNS disorders whose clinical manifestations have been attributed to CNS dysfunction {i.e., disorders resulting from inappropriate levels of neurotransmitter release, inappropriate properties of neurotransmitter receptors, and/or inappropriate interaction between neurotransmitters and neurotransmitter receptors). Several CNS disorders can be attributed to a deficiency of acetylcholine, dopamine, norepinephrine, and/or serotonin. Relatively common CNS disorders include pre-senile dementia (early-onset Alzheimer's disease), senile dementia (dementia of the Alzheimer's type), micro-infarct dementia, AIDS-related dementia, vascular dementia, Creutzfeld-Jakob disease, Pick's disease, Parkinsonism including Parkinson's disease, Lewy body dementia, progressive supranuclear palsy, Huntington's chorea, tardive dyskinesia, hyperkinesia, epilepsy, mania, attention deficit disorder, anxiety, dyslexia, schizophrenia, depression, obsessive- compulsive disorders, and Tourette's syndrome.

Subtypes of nAChRs are present in both the central and peripheral nervous systems, but the distribution of subtypes is heterogeneous. For instance, the subtypes which are predominant in vertebrate brain are α4β2, α7, and α3β2, whereas those which predominate at the autonomic ganglia are α3β4 and those of neuromuscular junction are αlβlδγ and αlβlδε (see for instance Dwoskin et al., Exp. Opin. Titer. Patents 10: 1561 (2000); and Schmitt and Bencherif, Annual Reports in Med. Chem. 35: 41 (2000)).

A limitation of some nicotinic compounds is that they elicit various undesirable pharmacological effects because of their interaction with nAChRs in peripheral tissues (for example, by stimulating muscle and ganglionic nAChR subtypes). It is therefore desirable to have compounds, compositions, and methods for preventing and/or treating various conditions or disorders (e.g., CNS disorders), including alleviating the symptoms of these disorders, where the compounds exhibit nicotinic pharmacology with a beneficial effect on the CNS nAChRs (e.g., upon the functioning of the CNS), but without significant associated effects on the peripheral nAChRs (compounds specific for CNS nAChRs). It is also highly desirable to have compounds, compositions, and methods that affect CNS function without significantly affecting those receptor subtypes which have the potential to induce undesirable side effects (e.g., appreciable activity at cardiovascular and skeletal muscle sites).

Methods for treating and/or preventing the above-described conditions and disorders by administering E-metanicotine compounds, particularly those which maximize the effect on CNS function without significantly affecting those receptor subtypes which have the potential to induce undesirable side effects, have been described in the art. Representative E-metanicotine compounds for use in treating and/or preventing the above- described disorders are disclosed, for example, in U.S. Pat. No. 5,212,188 to Caldwell et al, U.S. Pat. No. 5,604,231 to Smith et al, U.S. Pat. No. 5,616,707 to Crooks et al; U.S. Pat. No. 5,616,716 to Dull et al, U.S. Pat. No. 5,663,356 to Ruecroft et al, U.S. Pat. No. 5,726,316 to Crooks et al, U.S. Pat. No. 5,811,442 to Bencherif et al, U.S. Pat. No. 5,861,423 to Caldwell et al, PCT WO 97/40011; PCT WO 99/65876; PCT WO 00/007600; and U.S. patent application Ser. No. 09/391,747, filed on Sep. 8, 1999, the contents of each of which are hereby incorporated by reference.

It would be advantageous to provide new E-metanicotine compounds. The present invention provides such new compounds.

Summary of the Invention

E-metanicotine compounds are described herein, as well as pharmaceutically acceptable salts of the compounds, pharmaceutical compositions including the new compounds, and methods of treatment and/or prevention using the compounds.

The E-metanicotine compounds include a five-membered heteroaryl ring linked to an olefmic linker, which linker is in turn linked to a terminal amine moiety. Ideally, the linker is a branched olefmic linker with an alkyl group at a position alpha to a terminal amine, such as a 4-pentene-2-yl linking group.

The compounds can be prepared by performing a Heck reaction between a halogenated 5-membered heteroaryl ring, such as a halopyrrole or halofuran, and a double bond-containing compound. The double bond-containing compound typically includes either a hydroxy group, which is subsequently converted to an amine group to form the E- metanicotine compound, or includes a protected amine group, which is deprotected, following the Heck reaction, to form the E-metanicotine compound.

m one embodiment, the synthesis of the E-metanicotines involves forming an amine-protected 4-penten-2-amine intermediate, and coupling this intermediate via a Heck reaction with a halogenated five-membered heteroaryl ring. The choice of five-membered heteroaryl ring is not essential to the success of the Heck coupling reaction, although pyrrole and furan rings can be preferred. In another embodiment, the Heck coupling reaction takes place using an alkenol, such as 4-penten-2-ol, and the hydroxy group is converted to an amine group after the Heck coupling reaction takes place. The conversion can be effected, for example, by converting the hydroxy group to a tosylate, and displacing the tosylate with a suitable amine, such as methylamine. In this embodiment, the Heck coupling reaction still forms the same major and minor products, except that they include a hydroxy group rather than a protected amine group.

The compounds can be used directly, or the compounds or pharmaceutically acceptable salts thereof included in pharmaceutical compositions by combining them with a pharmaceutically acceptable excipient. The compounds and/or pharmaceutical compositions can be used to treat and/or prevent a wide variety of conditions or disorders. The disorders are particularly those disorders characterized by dysfunction of nicotinic cholinergic neurotransmission, including disorders involving neuromodulation of neurotransmitter release, such as dopamine release. The compounds can be used in methods for treatment and/pr prophylaxis of disorders, such as central nervous system (CNS) disorders, which are characterized by an alteration in normal neurotransmitter release. The compounds can also be used to treat certain conditions (e.g., a method for alleviating pain). The methods involve administering to a subject an effective amount of the E-metanicotine, a pharmaceutically acceptable salt thereof, or a pharmaceutical composition including the compound or a pharmaceutically acceptable salt thereof, as described herein.

The pharmaceutical compositions, when employed in effective amounts, can interact with relevant nicotinic receptor sites in a patient, and act as therapeutic and/or prophylactic agents in connection with a wide variety of conditions and disorders, particularly CNS disorders characterized by an alteration in normal neurotransmitter release. The pharmaceutical compositions can provide therapeutic benefit to individuals suffering from such disorders and exhibiting clinical manifestations of such disorders in that the compounds within those compositions, when employed in effective amounts, can (i) exhibit nicotinic pharmacology and affect relevant nicotinic receptors sites (e.g., activate nicotinic receptors), and (ii) modulate neurotransmitter secretion, and hence prevent and suppress the symptoms associated with those disorders, hi addition, the compounds can (i) increase the number of nicotinic cholinergic receptors of the brain of the patient, (ii) exhibit neuroprotective effects and (iii) when employed in effective amounts can exhibit relatively low levels of adverse side effects (e.g., significant increases in blood pressure and heart rate, significant negative effects upon the gastro-intestinal tract, and significant effects upon skeletal muscle).

The foregoing and other aspects of the present invention are explained in detail in the detailed description and examples set forth below.

Detailed Description of the Invention

The compounds described herein are E-metanicotines that include a five-membered heteroaryl ring attached to an olefmic linker, which in turn is linked to a terminal amine.

The linker ideally includes an alkyl group, such as a methyl group, at a position alpha to the terminal amine. One example of a preferred linker is a penten-2-amine linker. The compounds, pharmaceutical compositions, synthetic methods used to prepare the compounds and methods of treatment described herein will be better understood with reference to the following preferred embodiments. The following definitions will be useful in defining the scope of the invention:

As used herein, "aromatic" refers to 3 to 10, preferably 5 and 6-membered ring aromatic and heteroaromatic rings.

As used herein, "aromatic group-containing species" refer to moieties that are or include an aromatic group. Accordingly, phenyl and benzyl moieties are included in this definition, as both are or include an aromatic group.

As used herein, "aryl" refers to aromatic radicals having six to ten carbon atoms, such as phenyl, naphthyl, and the like; "substituted 'aryl" refers to aryl radicals further bearing one or more substituent groups as defined herein.

As used herein, "alkylaryl" refers to alkyl-substituted aryl radicals; "substituted alkylaryl" refers to alkylaryl radicals further bearing one or more substituent groups as defined herein; "arylalkyl" refers to aryl-substituted alkyl radicals; and "substituted arylalkyl" refers to arylalkyl radicals further bearing one or more substituent groups as defined herein.

As used herein, Ci_-6 alkyl radicals (lower alkyl radicals) contain from 1 to 6 carbon atoms in a straight or branched chain, and also include C_3-6 cycloalkyl moieties and alkyl radicals that contain C_3-6 cycloalkyl moieties.

As used herein, "alkenyl" refers to straight chain or branched hydrocarbon radicals including C₁-_S,. preferably Q-₅ and having at least one carbon-carbon double bond; "substituted alkenyl" refers to alkenyl radicals further bearing one or more substituent groups as defined herein.

As used herein, Ci_-6 alkoxy radicals contain from 1 to 6 carbon atoms in a straight or branched chain, and also include C_3-6 cycloalkoxy and alkoxy radicals that contain C_3-6 cycloalkyl moieties.

As used herein, aryl radicals are selected from phenyl, naphthyl, and indenyl.

As used herein, cycloalkyl radicals are saturated or unsaturated cyclic ring- containing radicals containing three to eight carbon atoms, preferably three to six carbon atoms; "substituted cycloalkyl" refers to cycloalkyl radicals further bearing one or more substituent groups as defined herein.

As used herein, halogen is chlorine, iodine, fluorine, or bromine.

As used herein, heteroaryl radicals contain from 3 to 10 members, preferably 5 or 6 members, including one or more heteroatoms selected from oxygen, sulfur, and nitrogen.

Examples of suitable 5-membered ring heteroaryl moieties include furyl, thiophenyl, pyrrolyl, imidazolyl, oxazolyl, thiazolyl, thienyl, tetrazolyl, and pyrazolyl. Examples of suitable 6-membered ring heteroaryl moieties include pyridinyl, pyrimidinyl, and pyrazinyl, of which pyridinyl and pyrimidinyl are preferred. The E-metanicotines include a 5-membered ring heteroaryl ring attached to an olefinic linker, but other heteroaryl rings can be present as substituents at one or more positions.

As used herein, "heterocyclyl" refers to saturated or unsaturated cyclic radicals containing one or more heteroatoms (e.g., O, N, S) as part of the ring structure and having two to seven carbon atoms in the ring; "substituted heterocyclyl" refers to heterocyclyl radicals further bearing one or more substituent groups as defined herein. Examples of suitable heterocyclyl moieties include, but are not limited to, piperidinyl, morpholinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, isothiazolidinyl, thiazolidinyl, isoxazolidinyl, oxazolidinyl, piperazinyl, tetrahydropyranyl, and tetrahydrofuranyl.

As used herein, polycycloalkyl radicals are fused cyclic ring structures. Representative polycycloalkyl radicals include, but are not limited to, adamantyl, bornanyl, norbornanyl, bornenyl, and norbornenyl. Polycycloalkyl radicals can also include one or more heteroatoms, such as N, O, or S.

As used herein, cycloalkyl radicals contain from 3 to 8 carbon atoms. Examples of suitable cycloalkyl radicals include, but are not limited to, cyclopropyl, cycloburyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

As used herein, the term "substituted" as used with any of the above terms, refers to the presence of one, two or three substituents such as alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocyclyl, substituted heterocyclyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl, arylalkyl, substituted arylalkyl, F, Cl, Br, I, NR¹R", CF₃, CN, NO₂, C₂ R¹, SH, SCH₃, N₃, SO₂ CH₃, OR', (CR¹R¹Oq OR¹, O-(CR'R^M)_q C₂R', SR¹, C(O)NR¹R", NR'C(=0)R", C(=O)R', C(=0)0R', 0C(=0)R', (CR¹R¹OqOCH₂C₂R¹, (CR'R")_qC(=O)R', (CR'R")_q C(CHCH₃)OR', O(CR'R")qC(=O)OR', (CR¹R¹OqC(O)NR¹R", (CR'R")_q NR¹R", CH=CHR¹, 0C(=0)NR'R", and NR'C(=0)0R" where q is an integer from 1 to 6 and R¹ and R" are individually hydrogen, or alkyl (e.g., Cπo alkyl, preferably C₁-₅ alkyl, and more preferably methyl, ethyl, isopropyl, tertiarybutyl or isobutyl), cycloalkyl (e.g., cyclopropyl cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and adamantyl), a non-aromatic heterocyclic ring wherein the heteroatom of the heterocyclic moiety is separated from any other nitrogen, oxygen or sulfur atom by at least two carbon atoms (e.g., quinuclidinyl, pyrollidinyl, and piperidinyl), an aromatic group-containing species (e.g., pyridinyl, quinolinyl, pyrimidinyl, furanyl, phenyl, and benzyl where any of the foregoing can be suitably substituted with at least one substituent group, such as alkyl, hydroxyl, alkoxyl, halo, or amino substituents). As used herein, an "agonist" is a substance that stimulates its binding partner, typically a receptor. Stimulation is defined in the context of the particular assay, or may be apparent in the literature from a discussion herein that makes a comparison to a factor or substance that is accepted as an "agonist" or an "antagonist" of the particular binding partner under substantially similar circumstances as appreciated by those of skill in the art. Stimulation may be defined with respect to an increase in a particular effect or function that is induced by interaction of the agonist or partial agonist with a binding partner and can include allosteric effects.

As used herein, an "antagonist" is a substance that inhibits its binding partner, typically a receptor. Inhibition is defined in the context of the particular assay, or may be apparent in the literature from a discussion herein that makes a comparison to a factor or substance that is accepted as an "agonist" or an "antagonist" of the particular binding partner under substantially similar circumstances as appreciated by those of skill in the art.

Inhibition may be defined with respect to a decrease in a particular effect or function that is induced by interaction of the antagonist with a binding partner, and can include allosteric effects.

As used herein, a "partial agonist" is a substance that provides a level of stimulation to its binding partner that is intermediate between that of a full or complete antagonist and an agonist defined by any accepted standard for agonist activity. It will be recognized that stimulation, and hence, inhibition is defined intrinsically for any substance or category of substances to be defined as agonists, antagonists, or partial agonists. As used herein, "intrinsic activity", or "efficacy," relates to some measure of biological effectiveness of the binding partner complex. With regard to receptor pharmacology, the context in which intrinsic activity or efficacy should be defined will depend on the context of the binding partner (e.g., receptor/ligand) complex and the consideration of an activity relevant to a particular biological outcome. For example, in some circumstances, intrinsic activity may vary depending on the particular second messenger system involved. See Hoyer, D. and Boddeke, H., Trends Pharmacol Sd. 14(7):270-5 (1993). Where such contextually specific evaluations are relevant, and how they might be relevant in the context of the present invention, will be apparent to one of ordinary skill in the art. As used herein, neurotransmitters whose release is mediated by the compounds described herein include, but are not limited to, acetylcholine, dopamine, norepinephrine, serotonin, and glutamate, and the compounds described herein function as agonists or partial agonists at one or more of the Central Nervous System (CNS) nAChRs.

I. Compounds

The compounds described herein are (E)-metanicotine-type compounds, and pharmaceutically acceptable salts thereof.

E-Metanicotines

The E-metanicotine compounds include compounds of the formula:

wherein:

Cy is a 5-membered heteroaryl ring,

Each E individually represent hydrogen, alkyl, substituted alkyl, halo substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl, arylalkyl or substituted arylalkyl;

E' represents alkyl, preferably methyl;

Z' and Z" individually represent hydrogen or alkyl (including cycloalkyl), and preferably at least one of Z' and Z is hydrogen, and most preferably Z' is hydrogen and Z is methyl; alternatively Z', Z , and the associated nitrogen atom can form a ring structure such as aziridinyl, azetidinyl, pyrollidinyl, piperidinyl, piperazinyl, morpholinyl and

both E groups on the double bond are preferably hydrogen, and m is 1, 2, 3, 4, 5, or 6.

In one embodiment, all of E are hydrogen, and in another embodiment, at least one of E is alkyl and the remaining E are hydrogen. In a preferred embodiment, E' is a methyl group.

Isomers, mixtures, including racemic mixtures, enantiomers, diastereomers and tautomers of these compounds, as well as pharmaceutically acceptable salts thereof, are also within the scope of the invention.

In one embodiment, Cy is a 5-membered ring heteroaryl of the following formula:

where Y and Y" are individually nitrogen, nitrogen bonded to a substituent species, oxygen, sulfur or carbon bonded to a substituent species, and Y¹ and Y'" are nitrogen or carbon bonded to a substituent species. The dashed lines indicate that the bonds (between Y and Y' and between Y' and Y") can be either single or double bonds. However, when the bond between Y and Y' is a single bond, the bond between Y' and Y" must be a double bond and vice versa. In cases in which Y or Y" is oxygen or sulfur, only one of Y and Y" is either oxygen or sulfur. At least one of Y, Y', Y", and Y'" must be oxygen, sulfur, nitrogen, or nitrogen bonded to a substituent species. It is preferred that no more than three of Y, Y¹, Y", and Y'" be oxygen, sulfur, nitrogen, or nitrogen bonded to a substituent species. It is further preferred that at least one, but no more than three, of Y, Y', Y", and Y'" be nitrogen.

Representative fϊve-membered ring heteroaryls include furan, thiophene, 2H- pyrrole, pyrrole, oxazole, thiazole, imidazole, pyrazole, isoxazole, isothiazole, 1,2,3- oxadiazole, 1,2,3-triazole, and 1,3,4-thiadiazole. Substituent species on Y', Y", and Y'", when adjacent, can combine to form one or more saturated or unsaturated, substituted or unsubstituted carbocyclic or heterocyclic rings containing, but not limited to, ether, acetal, ketal, amine, ketone, lactone, lactam, carbamate, or urea functionalities. Representative compounds of the invention include (3E)-N-methyl-4-(3-methyl-5- isoxazolyl)-4-penten-2-amine and (3E)-N-methyl-4-(5-isothiazolyl)-4-penten-2-amine.

Depending upon the identity and positioning of each individual E and E', certain compounds can be optically active (e.g., the compound can have one or more chiral centers, with R or S configurations). The present invention relates to racemic mixtures of such compounds as well as single enantiomer compounds.

II. Compound Preparation

The manner in which the (E)-metanicotine-type compounds described herein are synthetically produced can vary. For example, the compounds can be prepared by the palladium-catalyzed coupling reaction of an aromatic halide and a terminal olefin containing a protected amine substituent, removal of the protective group to obtain a primary or secondary amine, and optional alkylation to provide a secondary or tertiary amine. In particular, certain metanicotine-type compounds can be prepared by subjecting a halo-substituted, optionally substituted, 5-membered ring heteroaryl compound to a palladium-catalyzed coupling reaction using an olefin possessing a protected amine functionality (e.g., such an olefin provided by the reaction of a phthalimide salt with A- halo-1-pentene or 5-halo-l-hexene, etc.). See, Frank et al, J. Org. Chem., 43(15):2947- 2949 (1978); and Malek et al, J. Org. Chem., 47:5395-5397 (1982).

hi another embodiment, the compounds are synthesized by condensing an olefinic alcohol, such as 4-penten-2-ol, with an aromatic halide, such as a halo-substituted, optionally substituted, 5-membered ring heteroaryl compound. Typically, the types of procedures set forth in Frank et al, J. Org. Chem., 43: 2947-2949 (1978) and Malek et al,

J. Org. Chem., 47: 5395-5397 (1982) involving a palladium-catalyzed coupling of an olefin and an aromatic halide are used. The olefinic alcohol optionally can be protected as a t-butyldimethylsilyl ether prior to the coupling. Desilylation then produces the olefinic alcohol. The alcohol condensation product then is converted to an amine using the type of procedures set forth in deCosta et al, J. Org. Chem., 35: 4334-4343 (1992). Typically, the alcohol condensation product is converted to the aryl substituted olefinic amine by activation of the alcohol using methanesulfonyl chloride or p-toluenesulfonyl chloride, followed by mesylate or tosylate displacement using ammonia, or a primary or secondary amine. Thus, when the amine is ammonia, an aryl substituted olefinic primary amine compound is provided; when the amine is a primary amine such as methylamine or cyclobutylamine, an aryl substituted olefinic secondary amine compound is provided; and when the amine is a secondary amine such as dimethylamine or pyrrolidine, an aryl substituted olefinic tertiary amine compound is provided. Other representative olefinic alcohols include 5-hexen-2-ol, 3-methyl-4-penten-2-ol and 4-methyl-5-hexen-2-ol. Trifluoromethyl-substituted olefinic alcohols, such as l,l,l-trifluoro-4-penten-2-ol, can be prepared from l-ethoxy-2,2,2-trifluoro-ethanol and allyltrimethylsilane using the procedures of Kubota et al, Tetrahedron Letters, 33(10):1351-1354 (1992), or from trifluoroacetic acid ethyl ester and allyltributylstannane using the procedures of Ishihara et al, Tetrahedron Letters, 34(56): 5777-5780 (1993). Certain olefinic alcohols are optically active, and can be used as enantiomeric mixtures or as pure enantiomers in order to provide the corresponding optically active forms of aryl substituted olefinic amine compounds. When an olefinic allylic alcohol, such as methallyl alcohol, is reacted with an aromatic halide, an aryl substituted olefinic aldehyde is produced; and the resulting aldehyde can be converted to an aryl substituted olefinic amine compound by reductive amination (e.g., by treatment using an alkyl amine and sodium cyanoborohydride).

The synthesis of halogenated five-membered ring heteroaryls is well known, and several of them are commercially available. For example, Aldrich Chemicals sells 3- bromo-furan, 5-bromo-2-furoic acid, 2-bromo-thiazole, 4-bromoimidazole, 2-bromo- and 3-bromothiophene, 2-bromo-3-thiophenecarboxylic acid, 3-bromo-2-thiophenecarboxylic acid, 5-bromothiophene-2-carbonitrile, 4-bromothiophenol, 3-bromothiophenol, and 4- bromo-thiophenecarboxyaldehyde. Representative halogenated five-membered ring heteroaryls include 2-halo- and 3-halofuran, 2-halo- and 3-halothiophene, 2-halo-, 3-halo- or 4-halo-2H-pyrrole, 2-halo- or 3-halopyrrole, 2-halo-, 4-halo- or 5-halooxazole, 2-halo-, 4-halo- or 5-halothiazole, 2-halo-, 4-halo- or 5-haloimidazole, 3-halo-, 4-halo- or 5- halopyrazole, 3-halo-, 4-halo- or 5-haloisoxazole, 3-halo-, 4-halo- or 5-haloisothiazole, 3- halo- or 5-halo-l,2,4-oxadiazole, 4-halo- or 5-halo-l,2,3-triazole, and 2-halo- or 5-halo- 1,3,4-thiadiazole. Substitutions can be present at any position which does not include a halogen or a ring nitrogen, oxygen, or sulfur atom. Preferred aromatic halides are bromo and iodo compounds. Typically, substituent groups of these compounds are such that those groups can survive contact with those chemicals (e.g., tosylchloride and methylamine) and the reaction conditions experienced during the preparation of the aryl substituted olefinic amine compound. Alternatively, substituents such as -OH, -NH₂ and -SH can be protected as corresponding acyl compounds, or substituents such as -NH₂ can be protected as a phthalimide functionality. In the case of a dihaloaromatic, sequential palladium-catalyzed (Heck-type) couplings to two different olefinic side chains are possible.

The (E)-metanicotine-type compounds ideally possess a branched side chain, preferably with an alkyl group at a position alpha to the terminal amine. An example of a suitable side chain is a 4-penten-2-amine side chain. By using one synthetic approach, these compounds can be synthesized in a convergent manner, in which the side chain, N- methyl-N-(tert-butoxycarbonyl)-4-penten-2-amine is coupled with the appropriate halo- substituted five membered ring heteroaryl compound, under Heck reaction conditions, followed by removal of the tert-butoxycarbonyl protecting group. Typically, the types of procedures set forth in W. C. Frank et ah, J. Org. Chem. 43:2947 (1978) and N. J. Malek et ah, J. Org. Chem. 47:5395 (1982) involving a palladium-catalyzed coupling of an olefin and an aromatic halide are used. The required N-methyl-N-(tert-butoxycarbonyl)-4-penten- 2-amine can be synthesized as follows: (i) commercially available 4-penten-2-ol (Aldrich Chemical Company, Lancaster Synthesis hie.) can be treated with p-toluenesulfonyl chloride in pyridine to yield 4-penten-2-ol p-toluenesulfonate, previously described by T. Michel, et ah, Liebigs Ann. 11: 1811 (1996); (ii) the resulting tosylate can be heated with excess methylamine to yield N-methyl-4-penten-2 -amine; (iii) the resulting amine, such as previously mentioned by A. Viola et ah, J. Chem. Soc, Chem. Commun. 21: 1429 (1984), can be allowed to react with 1.2 molar equivalents of di-tert-butyl dicarbonate in dry tetrahydrofuran to yield the side chain, N-methyl-N-(tert-butoxycarbonyl)-4-penten-2- amine. The halo-substituted five-membered ring heteroaryl can be synthesized by any appropriate method.

In another embodiment, the side chain is introduced by coupling a halo-substituted five-membered ring heteroaryl with an olefin containing a secondary alcohol functionality, 4-penten-2-ol, under Heck reaction conditions; and the resulting pyridinyl alcohol intermediate can be converted to its p-toluenesulfonate ester, followed by treatment with methylamine. Typically, the types of procedures set forth in W. C. Frank et ah, J. Org. Chem. 43: 2947 (1978) and N. J. Malek et ah, J. Org. Chem. 47: 5395 (1982) involving a palladium-catalyzed coupling of an olefin and an aromatic halide are used. The hydroxyl- group containing intermediate can be treated with 2 molar equivalents of p-toluenesulfonyl chloride in dry pyridine at O⁰C to produce the corresponding p-toluensulfonate. The tosylate intermediate can be treated with a large excess of of methylamine (typically as a 40% aqueous solution), containing a small amount of ethanol as a co-solvent to produce the corresponding 4-penten-2-amine.

Optically active forms of certain aryl substituted olefmic amine compounds can also be provided. In one synthetic approach, the latter type of compound is synthesized by coupling a halo-substituted 5-membered ring heteroaryl with an olefin possessing a chiral, secondary alcohol functionality, (2R)-4-penten-2-ol, under Heck reaction conditions. The resulting chiral pyridinyl alcohol intermediate, can be converted to its corresponding p- toluenesulfonate ester, which can subsequently be treated with methylamine, resulting in tosylate displacement with inversion of configuration. Typically, the types of procedures set forth in W. C. Frank et ah, J. Org. Chem. 43: 2947 (1978) and N. J. Malek et at, J. Org. Chem. 47: 5395 (1982) involving a palladium-catalyzed coupling of an aromatic halide and an olefin are used. The chiral side chain, (2R)-4-penten-2-ol can be prepared by treatment of the chiral epoxide, (R)-(+)-propylene oxide (commercially available from Fluka Chemical Company) with vinylmagnesium bromide and copper(I) iodide in tetrahydrofuran at low temperatures (-25 to -10° C) using the general synthetic methodology of A. Kalivretenos, J. K. Stille, and L. S. Hegedus, J. Org. Chem. 56: 2883 (1991). The resulting chiral alcohol is subjected to a Heck reaction with the halogenated 5- membered ring heteroaryl in acetonitrile-triethylamine (1:1, v/v) using a catalyst consisting of 1 mole % palladium(H) acetate and 4 mole % tri-o-tolylphosphine. The reaction is done by heating the components at 140° C for 14 hours in a sealed glass tube, to produce the Heck reaction product. The resulting chiral alcohol can be treated with 3 molar equivalents of p-toluenesulfonyl chloride in dry pyridine at 0° C to afford the tosylate intermediate. The p-toluenesulfonate ester can be heated with a large excess of methylamine (typically as a 40% aqueous solution, containing a small amount of ethanol as a co-solvent) to produce the (2S)-(4E)-N-methyl-5-(5-membered ring heteroaryl)-4-penten-2-amine, where the linkage to the heteroaryl ring occurs at the position in which the halogen was initially present. In a similar manner, the corresponding aryl substituted olefinic amine enantiomer, such as (2R)-(4E)-N-methyl-5-(5-membered ring heteroaryl)-4-penten-2-amine, can be synthesized by the Heck coupling of a suitable halogenated 5-membered ring heteroaryl and (2S)-4-penten-2-ol. The resulting intermediate, (2S)-(4E)-5-(5-membered ring heteroaryl)-4-penten-2-ol, can be converted to its p-toluenesulfonate, which can be subjected to methylamine displacement. The chiral alcohol, (2S)-4-penten-2-ol, is prepared from (S)-(-)-propylene oxide (commercially available from Aldrich Chemical Company) using a procedure analogous to that described for the preparation of (2R)-4-penten-2-ol from (R)-(+)-propylene oxide as reported by A. Kalivretenos, J. K. Stille, and L. S. Hegedus, J. Org. Chem. 56: 2883 (1991).

Alternatively, the palladium catalyzed coupling reaction can be carried out using a protected chiral olefinic amine. Thus Heck reaction of (2S)-N-methyl-N-(t- butoxycarbonyl)-4-penten-2-amine with a suitable halogenated 5-membered ring heteroaryl compound, and subsequent removal of the t-butoxycarbonyl group, generates a (2S)-(4E)-N-methyl-5-(5-membered ring heteroaryl)-4-penten-2-amine. The necessary (2S)-N-methyl-N-(t-butoxycarbonyl)-4-penten-2-amine is made by converting the above- mentioned (2R)-4-penten-2-ol into the corresponding tosylate, displacement of the tosyl group with methylamine, and protection of the amine with di-t-butoxy dicarbonate.

Compounds of the present invention can also be made by reacting ylides, derived from five membered heteroarylmethyl phosphonium salts and phosphonate esters, with appropriate aldehydes and ketones (the Wittig and Horner-Emmons reactions). Such phosphonium salts and phosphonate esters are reported in the literature (for instance, see

DeShong et al., J. Org. Chem. 53: 1356 (1988)). Thus reaction of diethyl 5- isoxazolylmethylphophonate with N-methyl-N-(tert-butoxycarbonyl)-3-aminobutanal will produce (3E)-N-methyl-N-(t-butoxycarbonyl)-4-(5-isoxazolyl)-4-buten-2-amine. Removal of the tert-butoxycarbonyl group with trifluoroacetic acid will produce (3E)-N-methyl-4-

(5-isoxazolyl)-4-buten-2-amine. The requisite N-methyl-N-(tert-butoxycarbonyl)-3- aminobutanal can be produced from the corresponding alcohol using techniques described by M. Adamczyk and Y. Y. Chen in PCT International Application WO 9212122. The alcohol, N-methyl-N-(tert-butoxycarbonyl)-3-amino-l-butanol, can be made from commercially available 4-hydroxy-2-butanone (Lancaster Synthesis, Inc.) by sequential reductive animation (with methylamine and sodium cyanoborohydride, using chemistry reported by R. F. Borch in Org. Syn., 52:124 (1974)) and protection with di-tert-butyl dicarbonate. Similar reactions using other aldehydes and other ylides will yield other compounds of the present invention.

Pharmaceutically Acceptable Salt Forms

The compounds can be employed in a free base form or in a salt form (e.g., as pharmaceutically acceptable salts). The pharmaceutically acceptable salts can be prepared by direct reaction of the compound with a pharmaceutically acceptable acid. Such procedures are known to those of skill in the art.

Examples of suitable pharmaceutically acceptable salts include inorganic acid addition salts such as hydrochloride, hydrobromide, sulfate, phosphate, and nitrate; organic acid addition salts such as acetate, galactarate, propionate, succinate, lactate, glycolate, malate, tartrate, citrate, maleate, fumarate, methanesulfonate, p-toluenesulfonate, and ascorbate; salts with acidic amino acids such as aspartate and glutamate; alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; ammonium salt; organic basic salts such as trimethylamine salt, triethylamine salt, pyridine salt, picoline salt, dicyclohexylamine salt, and N,N'- diben∑ylethylenediamine salt; and salts with basic amino acids such as lysine salt and arginine salt.

The salts may be in some cases hydrates or ethanol solvates. Representative salts are provided as described in U.S. Pat. No. 5,597,919 to Dull et al., U.S. Pat. No. 5,616,716 to Dull et al. and U.S. Pat. No. 5,663,356 to Ruecroft et al.

III. Pharmaceutical Compositions

The pharmaceutical compositions of the present invention include the compound described herein, in the pure state or in the form of a composition in which the compounds are combined with any other pharmaceutically compatible product, which can be inert or physiologically active. Such compositions can be administered, for example, orally, parenterally, rectally, or topically. Examples of solid compositions for oral administration include, but are not limited to, tablets, pills, powders (gelatin capsules, cachets), and granules. In these compositions, the active compound is mixed with one or more inert diluents, such as starch, cellulose, sucrose, lactose, or silica; ideally, under a stream of an inert gas such as argon.

The compositions can also include substances other than diluents, for example, one or more lubricants such as magnesium stearate or talc, a colorant, a coating (coated tablets), or a varnish.

Examples of liquid compositions for oral administration include, but are not limited to, solutions, suspensions, emulsions, syrups, and elixirs that are pharmaceutically acceptable and typically contain inert diluents such as water, ethanol, glycerol, vegetable oils, or liquid paraffin. These compositions can comprise substances other than the diluents, for example, wetting agents, sweeteners, thickeners, flavors, and stabilizers.

Sterile compositions for parenteral administration can include, for example, aqueous or nonaqueous solutions, suspensions, and emulsions. Examples of suitable solvents and vehicles include, but are not limited to aqueous solutions, preferably buffered aqueous solutions, propylene glycol, a polyethylene glycol, vegetable oils, especially olive oil, injectable organic esters, for example ethyl oleate, and other appropriate organic solvents. These compositions can also include adjuvants, especially wetting agents, isotonicity agents, emulsifiers, dispersants, and stabilizers. Such sterile compositions can be sterilized in a number of ways, for example, by asepticizing filtration, by incorporating sterilizing agents into the composition, by irradiation and by heating. They can also be prepared in the form of sterile solid compositions which can be dissolved at the time of use in sterile water or any other sterile injectable medium.

Examples of compositions for rectal administration include, but are not limited to, suppositories and rectal capsules that, in addition to the active product, can include excipients such as cocoa butter, semi-synthetic glycerides, and polyethylene glycols.

Compositions for topical administration can, for example, be creams, lotions, eyewashes, collutoria, nasal drops or aerosols. The pharmaceutical compositions also can include various other components as additives or adjuncts. Exemplary pharmaceutically acceptable components or adjuncts which are employed in relevant circumstances include antioxidants, free radical scavenging agents, peptides, growth factors, antibiotics, bacteriostatic agents, immunosuppressives, anticoagulants, buffering agents, anti-inflammatory agents, antipyretics, time release binders, anesthetics, steroids, and corticosteroids. Such components can provide additional therapeutic benefit, act to affect the therapeutic action of the pharmaceutical composition, or act towards preventing any potential side effects which may be posed as a result of administration of the pharmaceutical composition. In certain circumstances, a compound of the present invention can be employed as part of a pharmaceutical composition with other compounds intended to prevent or treat a particular disorder.

IV. Methods of Treatment

The compound described herein are useful for treating those types of conditions and disorders for which other types of nicotinic compounds have been proposed as therapeutics. See, for example, Williams et al, DN&P 7(4):205-227 (1994); Arneric et al, CNS Drug Rev. 1(1): 1-26 (1995); Arneric et al, Exp. Opin. Invest. Drugs 5(l):79-100

(1996); Bencherif et al, J. Pharmacol. Exp. Ther. 279:1413 (1996); Lippiello et al, J.

Pharmacol. Exp. Ther. 279:1422 (1996); Damaj et al, Neuroscience (1997); Holladay et al, J. Med. Chem. 40(28): 4169-4194 (1997); Bannon et al, Science 279: 77-80 (1998);

PCT WO 94/08992; PCT WO 96/31475; and U.S. Patent Nos. 5,583,140 to Bencherif et al; 5,597,919 to Dull et al; and 5,604,231 to Smith et al

The compounds can also be used as adjunct therapy in combination with existing therapies in the management of the aforementioned types of diseases and disorders. In such situations, it is preferably to administer the active ingredients in a manner that minimizes effects upon nAChR subtypes such as those that are associated with muscle and ganglia. This can be accomplished by targeted drug delivery and/or by adjusting the dosage such that a desired effect is obtained without meeting the threshold dosage required to cause significant side effects. The pharmaceutical compositions can be used to ameliorate any of the symptoms associated with those conditions, diseases, and disorders. Examples of conditions and disorders that can be treated include neurological disorders, neurodegenerative disorders, in particular, CNS disorders, and inflammatory disorders. CNS disorders can be drug induced; can be attributed to genetic predisposition, infection or trauma; or can be of unknown etiology. CNS disorders comprise neuropsychiatric disorders, neurological diseases, and mental illnesses, and include neurodegenerative diseases, behavioral disorders, cognitive disorders, and cognitive affective disorders. There are several CNS disorders whose clinical manifestations have been attributed to CNS dysfunction {i.e., disorders resulting from inappropriate levels of neurotransmitter release, inappropriate properties of neurotransmitter receptors, and/or inappropriate interaction between neurotransmitters and neurotransmitter receptors). Several CNS disorders can be attributed to a deficiency of choline, dopamine, norepinephrine, and/or serotonin.

Examples of CNS disorders that can be treated using the E-metanicotine compounds and pharmaceutically acceptable salts described herein, and pharmaceutical compositions including these compounds and salts, include pre-senile dementia (early onset Alzheimer's disease), senile dementia (dementia of the Alzheimer's type), Lewy Body dementia, micro-infarct dementia, AIDS-related dementia, HIV-dementia, multiple cerebral infarcts, Parkinsonism including Parkinson's disease, Pick's disease, progressive supranuclear palsy, Huntingdon's chorea, tardive dyskinesia, hyperkinesia, epilepsy, mania, attention deficit disorder, anxiety, depression, dyslexia, schizophrenia depression, obsessive-compulsive disorders, Tourette's syndrome, mild cognitive impairment (MCI), age-associated memory impairment (AAMI), premature amnesic and cognitive disorders which are age-related or a consequence of alcoholism, or immunodeficiency syndrome, or are associated with vascular disorders, with genetic alterations (such as, for example, trisomy 21) or with attention deficiencies or learning deficiencies, acute or chronic neurodegenerative conditions such as amyotrophic lateral sclerosis, multiple sclerosis, peripheral neurotrophies, and cerebral or spinal traumas. In addition, the compounds can be used to treat nicotine addiction and/or other behavioral disorders related to substances that lead to dependency {e.g., alcohol, cocaine, heroin and opiates, psychostimulants, benzodiazepines, and barbiturates), and to treat obesity. The compounds can also be used to treat pathologies exhibiting an inflammatory character within the gastrointestinal system such as Crohn's disease, irritable bowel syndrome and ulcerative colitis, and diarrheas. The manner in which the compounds or their pharmaceutically acceptable salts are administered can vary. The compounds can be administered by inhalation (e.g., in the form of an aerosol either nasally or using delivery articles of the type set forth in U.S. Patent No. 4,922,901 to Brooks et al.); topically {e.g., in lotion form); orally (e.g., in liquid form within a solvent such as an aqueous or non-aqueous liquid, or within a solid carrier); intravenously (e.g., within a dextrose or saline solution); as an infusion or injection (e.g., as a suspension or as an emulsion in a pharmaceutically acceptable liquid or mixture of liquids); intrathecally; intracerebroventricularly; or transdermally (e.g., using a transdermal patch). Although it is possible to administer the compounds in the form of a bulk active chemical, it is preferred to present each compound in the form of a pharmaceutical composition or formulation for efficient and effective administration. Exemplary methods for administering such compounds will be apparent to the skilled artisan. For example, the compounds can be administered in the form of a tablet, a hard gelatin capsule or as a time- release capsule. As another example, the compounds can be delivered transdermally using the types of patch technologies available from Novartis and Alza Corporation. The administration of the pharmaceutical compositions of the present invention can be intermittent, or at a gradual, continuous, constant or controlled rate to a warm-blooded animal, (e.g., a mammal such as a mouse, rat, cat, rabbit, dog, pig, cow, or monkey); but, advantageously, the compounds are preferably administered to a human being, hi addition, the time of day and the number of times per day that the pharmaceutical formulation is administered can vary. Administration preferably is such that the active ingredients of the pharmaceutical formulation interact with receptor sites within the body of the subject that affect the functioning of the CNS or of the gastrointestinal (GI) tract. More specifically, in treating a CNS disorder administration preferably is such so as to optimize the effect upon those relevant receptor subtypes which have an effect upon the functioning of the CNS, while minimizing the effects upon muscle-type receptor subtypes. Other suitable methods for administering the compounds are described in U.S. Patent No. 5,604,231 to Smith et al., the disclosure of which is incorporated herein by reference in its entirety.

The appropriate dose of the compounds is that amount effective to prevent occurrence of the symptoms of the disorder or to treat some symptoms of the disorder from which the patient suffers. By "effective amount," "therapeutic amount," or "effective dose" is meant that amount sufficient to elicit the desired pharmacological or therapeutic effects, thus resulting in effective prevention or treatment of the disorder. Thus, when treating a CNS disorder, an effective amount of the compounds is an amount required to deliver, across the blood-brain barrier of the subject, a sufficient amount of the free base drug to bind to relevant receptor sites in the brain of the subject, and to modulate relevant nicotinic receptor subtypes (e.g., provide neurotransmitter secretion, thus resulting in effective prevention or treatment of the disorder). Prevention of the disorder is manifested by at least delaying the onset of the symptoms of the disorder or reducing the severity of the symptoms. Treatment of the disorder is manifested by a decrease in the symptoms associated with the disorder or an amelioration of the recurrence of the symptoms of the disorder.

The effective dose can vary, depending upon factors such as the condition of the patient, the severity of the symptoms of the disorder, and the manner in which the pharmaceutical composition is administered. For human patients, the effective dose of typical compounds generally requires administering the compounds in an amount sufficient to modulate relevant receptors to affect neurotransmitter (e.g., dopamine) release but the amount should be insufficient to induce effects on skeletal muscles and ganglia to any significant degree. The effective dose of the compounds will of course differ from patient to patient but in general includes amounts starting where CNS effects or other desired therapeutic effects occur, but below the amount where muscular effects are observed.

The doses depend on the desired effect, the duration of treatment and the administration route used; they are generally between 0.05 mg and 100 mg of active substance per day orally for an adult. Generally speaking, a medical doctor will determine the appropriate dosage as a function of the age, weight and all the other factors specific to the patient.

The compounds of the present invention, when employed in effective amounts in accordance with the method of the present invention, often lack the ability to elicit activation of human ganglion nAChRs to any significant degree. This selectivity of the compounds of the present invention against those nAChRs responsible for cardiovascular side effects is demonstrated by a lack of the ability of those compounds to activate nicotinic function of adrenal chromaffin tissue. As such, such compounds have poor ability to cause isotopic rubidium ion flux through nAChRs in cell preparations derived from the adrenal gland. Generally, typical preferred compounds useful in carrying out the present invention maximally activate isotopic rubidium ion flux by less than 10 percent, often by less than 5 percent, of that maximally provided by S(-) nicotine.

The compounds are effective towards providing some degree of prevention of the progression of CNS disorders, ameliorating the symptoms of CNS disorders, and ameliorating to some degree the recurrence of CNS disorders. However, such effective amounts of those compounds are not sufficient to elicit any appreciable undesired nicotinic effects, as is demonstrated by decreased effects on preparations believed to reflect effects on the cardiovascular system, or effects to skeletal muscle. As such, administration of compounds of the present invention provides a therapeutic window in which treatment of certain CNS disorders is provided, and undesired peripheral nicotinic effects/side effects are avoided. That is, an effective dose of a compound of the present invention is sufficient to provide the desired effects upon the CNS, but is insufficient {i.e., is not at a high enough level) to provide undesirable side effects. Preferably, effective administration of a compound of the present invention resulting in treatment of CNS disorders occurs upon administration of less than 1/3, frequently less than 1/5, and often less than 1/10, that amount sufficient to cause any side effects to a significant degree.

The following examples are provided to illustrate the present invention, and should not be construed as limiting thereof.

Example 1: Determination of Binding to Relevant Receptor Sites

The interaction of the compounds described herein with relevant receptor sites can be determined in accordance with the techniques described in U.S. Pat. No. 5,597,919 to Dull et al. Inhibition constants (Ki values), reported in nM, can be calculated from the IC₅₀ values using the method of Cheng et al, Biochem, Pharnacol. 22:3099 (1973). Low binding constants indicate that the components of the compounds described herein exhibit good high affinity binding to certain CNS nicotinic receptors.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

That which is claimed is:

1. A compound having the formula:

wherein:

Cy is a 5- heteroaryl ring, optionally substituted with one or two substituents Z,

E individually represents hydrogen, alkyl, or halo substituted alkyl,

E' is alkyl,

Z' and Z" individually represent hydrogen or alkyl,

m is 1, 2, 3, 4, 5, or 6,

Z is a non-hydrogen substituent selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocyclyl, substituted heterocyclyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, alkylaryl, substituted alkylaryl, arylalkyl, substituted arylalkyl, F, Cl, Br, I, NR'R", CF₃, CN, NO₂, C₂ R', SH, SCH₃, N₃, SO₂ CH₃, OR¹, (CR'R'% OR¹, 0-(CR¹R¹Oq C₂ R¹, SR', C(=O)NRR", NR'C(=O)R", C(=O)R', C(=O)OR', OC(=O)R', (CR'R")_q OCH₂ C₂ R', (CR'R")_q C(^O)R', (CR'R")_q C(CHCH₃)OR¹, O(CR'R")_q C(=O)OR', (CR'R")_q C(=0)NR'R", (CR'R")_q NR¹R", CH=CHR¹, OC(=O)NR'R", and NR'C(=0)0R^M,

where q is an integer from 1 to 6 and R' and R" are individually hydrogen, Ci-io alkyl, cycloalkyl, a non-aromatic heterocyclic ring wherein the heteroatom of the heterocyclic moiety is separated from any other nitrogen, oxygen or sulfur atom by at least two carbon atoms, or an aromatic group-containing species selected from the group consisting of pyridinyl, quinolinyl, pyrimidinyl, furanyl, phenyl, and benzyl, where any of the foregoing can be suitably substituted with at least one substituent group, such as alkyl, hydroxyl, alkoxyl, halo, or amino substituents,

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1, wherein the E are all hydrogen.

; 3. The compound of claim 2, wherein E' is methyl.

4. The compound of claim 1, wherein Cy is a 5-membered ring heteroaryl of the following formula:

where Y and Y" are individually nitrogen, nitrogen bonded to a substituent species, oxygen, sulfur or carbon bonded to a substituent species, and Y' and Y'" are nitrogen or carbon bonded to a substituent species,

the dashed lines indicate that the bonds (between Y and Y' and between Y' and Y") can be either single or double bonds,

when the bond between Y and Y' is a single bond, the bond between Y' and Y" is a double bond and vice versa,

when Y or Y" is oxygen or sulfur, only one of Y and Y" is either oxygen or sulfur, and

at least one of Y, Y', Y", and Y'" is oxygen, sulfur, nitrogen, or nitrogen bonded to a substituent species.

5. The compound of claim 4, wherein no more than three of Y, Y¹, Y", or Y'" are oxygen, sulfur, nitrogen, or nitrogen bonded to a substituent species.

6. The compound of claim 4, wherein at least one, but no more than three, of Y, Y¹, Y", or Y"¹ are nitrogen.

7. A compound selected from the group consisting of (3E)-N-methyl-4-(3-methyl- 5-isoxazolyl)-4-buten-2 -amine and (3E)-N-methyl-4-(5-isothiazolyl)-4-buten-2-amine.

8. A pharmaceutical composition comprising a compound of any of claims 1-7 along with a pharmaceutically acceptable carrier.

> 9. A method for treating a CNS disorder, comprising administering to a subject in need thereof an effective amount of a composition comprising a compound of any of claims 1-7, or a pharmaceutically acceptable salt thereof, wherein the compound can optionally be administered along with a pharmaceutically acceptable carrier.