Compositions of novel opioid compounds and method of use thereof

BACKGROUND OF THE INVENTION

1. Technical Field

2. Background of Related Art

In the study of opioid biochemistry, a variety of endogenous opioid compounds and non-endogenous opioid compounds have been identified. In this effort, significant research has been focused on understanding the mechanism of opioid drug action, particularly as it relates to cellular and differentiated tissue opiate receptors.

Opioid drugs typically are classified by their binding selectivity in respect of the cellular and differentiated tissue receptors to which a specific drug species binds as a ligand. These receptors include mu (μ), delta (δ), sigma (σ) and kappa (κ) receptors.

The well-known narcotic opiates, such as morphine and its analogs, are selective for the opiate mu receptor. Mu receptors mediate analgesia, respiratory depression, and inhibition of gastrointestinal transit. Kappa receptors mediate analgesia and sedation. Sigma receptors mediate various biological activities.

The existence of the opioid delta receptor is a relatively recent discovery that followed the isolation and characterization of endogenous enkephalin peptides that are ligands for the delta receptor. Delta receptors mediate analgesia, but do not appear to inhibit intestinal transit in the manner characteristic of mu receptors.

Opioid agents frequently are characterized as either agonists or antagonists. Agonists and antagonists are agents that recognize and bind to receptors, affecting (either initiating or blocking) biochemical/physiological sequences, a process known as transduction. Agonists inhibit or suppress neurotransmitter outputs in tissues containing receptors, e.g., inhibiting pain responses, or affecting other output-related phenomena. Antagonists also bind to receptors, but do not inhibit neurotransmitter outputs. Thus, antagonists bind to the receptor sites and block the binding of agonist species that are selective for the same receptor.

Various physiological effects of the known peptide-based opioid ligands have been studied, including: analgesia; respiratory depression; gastrointestinal effects; mental, emotional, and cognitive process function; and mediation/modulation of other physiological processes.

There is a continuing need in the art for improved opioid compounds, particularly compounds that are free of addictive character and other adverse side effects of conventional opiates such as morphine.

Previous disclosed diarylmethylpiperazine compounds exhibiting delta receptor agonist activities produced seizure-like convulsion activity in mice and rats after a rapid bolus iv administration through central (central nervous system, CNS) mechanism. Similarly, these compounds including current therapeutic analgesics possessing mu opioid receptor agonist activity produce respiratory depressive, nausea and emesis effects, addictive effects and abuse liability through a central mechanism. Delta and mu opioid receptors are localized in peripheral organs and tissues. Various physiological effects are known for those peripheral organs and tissues: gastro-intestinal tracts disorder such as antidiarrhea, and irritable bowl syndrome, cough, bladder functional modulation, genital organ regulation such as vas deferens contractility, immuno-modulation, and cardioprotection for heart attack. For those peripheral applications, compounds that lack central side effects are desirable.

The present invention described a series of novel opioid compounds, with potent delta and/or mu receptor agonist activities, that produce essentially no central mechanism side effects as evident from the lack of centrally mediated seizure-like convulsion activity and antinociception in tail-pinch assay after a rapid bolus iv injection of a high dose in mice.

SUMMARY OF THE INVENTION

Historically, the opioid compounds reported in the literature have a fixed addressing group, namely the substituent at A ring, such as shown below.

The compounds presented herein are compounds with changeable or functionalized addressing group(s). Since it is a functionalized addressing group, many modifications may be made at the addressing group to fine-tune the properties of the drug candidate thereby synthesizing many potential compounds for screening.

In one aspect the present invention relates to compounds as shown below in formula 1,

Z is H, O(CH2)nCH3, wherein n=0 to 4, or OH;

X which is C═O or SO2which is on the meta or para position of the phenyl ring;

DL is di-functional amine linker having a nitrogen that is covalently bonded to the carbon or sulfur atom of group X via an amide bond;

Q is either —CH2— or —(CH2)m—Ar—, wherein m is 1 or 2, wherein the di-functional linker is covalently bonded to the terminal carbon of the group Q;

Ar is a disubstituted 5- or 6-membered carbocyclic or heterocyclic aromatic ring;

n is 0, 1, 2, 3, 4, or 5 wherein any one carbon in the chain may optionally be a carbonyl;

R2is methyl, ethyl or H. The compounds of formula 1 include all isomers and/or racemic mixture thereof.

In another aspect, the present invention relates to compounds according to formula (2):

wherein

Z is H, O(CH2)nCH3, wherein n=0 to 4, or OH;

X which is C═O or SO2which is on the meta or para position of the phenyl ring;

DL is di-functional amine linker having a nitrogen that is covalently bonded to the carbon or sulfur atom of group X via an amide bond;

R4is: —OR5, —CO—NR6R7, —O—R8, or —R9COR10, wherein R5, R6, R7, R8, R9and R10is the same or different and selected from the R1group. The compounds of formula 2 include all isomers and/or racemic mixture thereof.

The amine linker may include one of the following groups, wherein R3is C1-C6alkyl, C1-C6cycloalkyl, or C1-C6cycloalkylmethyl.

In another aspect, the present invention relates to compounds comprising modifiers to the diethylamide phenyl substituent, wherein an incorporated functional group will be a synthetic entry for introducing property modifiers, as shown in formula 3

wherein X which is C═O or SO2which is on the meta or para position of the phenyl ring;

a di-functional amine linker having a nitrogen that is covalently bonded to the carbon or sulfur atom of group X via an amide bond and functional groups are built into the N,N-diethylamide moiety. Consequently, the added functional group makes the substituent changeable because many new phenyl substituents can be synthesized thru chemical transformations of the incorporated functional groups. Di-functional amines are used as synthetic precursors for the synthesis of new opioid ligands including:

These compounds can be used for making compounds with functionalized amide addressing group or sulfonamide addressing groups.

The compounds presented herein are compounds with functionalized A-ring phenyl substituents in contrast to prior art compounds that are saturated hydrocarbon, and as such, inaccessible for further chemical transformations. Since these are changeable or replaceable phenyl substituents, many chemical transformations can be done at the substituents to produce new opioid ligands with new A-ring phenyl substituents. Applying the methods of modifying the A-ring phenyl substituents, a large number of novel compounds, including racemic mixtures or individual isomers thereof, can be derived from this design.

The following schematic provides an example of an opioid ligand with functionalized substituents:

Examples of applicable “R” may include the following:

Likewise, functionalized sulfonamide A-ring phenyl substituent may be prepared wherein the sulfonamide may be in either the para or meta position.

In another aspect, the present invention relates to a method for preventing or treating a disease or condition selected from the group consisting of combating drug addiction, alcohol addiction, drug overdose, mental illness, bladder dysfunctions, neurogenic bladder, interstitial cystitis, urinary incontinence, premature ejaculation, inflammatory pain, peripherally mediated and neuropathic pain, cough, lung edema, diarrhea, cardiac disorders, cardioprotection, depression, and cognitive, respiratory, diarrhea, gastro-intestinal disorders, immunomodulation, anti-tumor agents, arthritis, psoriasis, asthma, inflammatory bowel disease, disorders of respiratory function, gastro-intestinal disorders, functional bowel disease, sexual dysfunctions, functional GI disorders, irritable bowel syndrome, functional distension, functional pain, non-ulcerogenic dyspepisa, disorders of motility or secretion, urogenital tract disorders, non-somatic pain, rejection in organ transplant and skin graft by administering to a mammal a therapeutically effective amount of a compound, salt or solvate of formula 1:

Z is H, O(CH2)nCH3, or OH;

X which is C═O or SO2which is on the meta or para position of the phenyl ring;.

DL is di-functional amine linker having a nitrogen that is covalently bonded to the carbon or sulfur atom of group X via an amide bond, and the other function of the di-functional linker (either oxygen or nitrogen) is covalently bonded to the terminal carbon of group Q;

‘Q’ is either —CH2— or —(CH2)m—Ar—, wherein m is 1 or 2;

Ar is a disubstituted 5- or 6-membered carbocyclic or heterocyclic aromatic ring;

n is 0, 1, 2, 3, 4, or 5 wherein any one carbon in the chain may optionally be a carbonyl;

Another aspect of the present invention relates to a compound of the formula

Z is H, O(CH2)nCH3, wherein n=0 to 4, or OH;

X is C═O which is on the meta or para position of the phenyl ring;

DL is a di-functional amine linker having a nitrogen that is covalently bonded to the atom of group X;

wherein the di-functional amine linker is selected from the group consisting of:

and wherein the bonding nitrogen that is covalently bonded to the carbon atom of group X has lost a hydrogen during the bonding process.

One broad aspect of the present invention relates to compounds, including inter alia pharmaceutical compositions comprising the same and methods for making and using the same. In particular, the invention relates to cyclic compounds and compositions comprising the same—as well as their preparation—and their use as selective agonists for the delta (δ) and/or mu (μ) receptor and preferably peripheral receptors.

While the compounds of the invention are described hereinafter with primary reference to diarylmethylpiperazines, piperidines and derivatives thereof, including their respective ester and salt forms, it will be recognized that the methods of the invention for treatment or prophylaxis of various disease states and physiological conditions may include use of a wide variety of diarylmethylpiperazines.

In a particularly preferred method of the invention, treatment or prophylaxis of overactive bladder or urinary incontinence is effected by administering to a subject in need of such treatment or prophylaxis an effective amount of a compound of formula (1) or a pharmaceutically acceptable ester or salt thereof.

Examples of pharmaceutically acceptable esters of the compound of formula (1) include carboxylic acid esters of the hydroxyl group in the compound of formula (1) in which the non-carbonyl moiety of the carboxylic acid portion of the ester grouping is selected from straight or branched chain alkyl (e.g. n-propel, t-butyl, n-butyl), alkoxyalkyl (e.g. methoxymethyl), arylalkyl (e.g. benzyl), aryloxyalky (e.g. phenoxymethyl), and aryl (e.g. phenyl); alkyl-, aryl-, or arylalkylsulfonyl (e.g. methanesulfonyl); amino acid esters (e.g. L-valyl or L-isoleucyl); dicarboxylic acid esters (e.g. hemisuccinate); carbonate esters (e.g. ethoxycarbonyl); carbamate esters (e.g. dimethylaminocarbonyl, (2-aminoethyl)aminocarbonyl); and inorganic esters (e.g. mono-, di- or triphosphate).

Examples of pharmaceutically acceptable salts of the compound of formula (1) include salts derived from an appropriate base, such as an alkali metal (for example, sodium, potassium), an alkaline earth metal (for example, calcium, magnesium), ammonium and NR′4+(wherein R′ is C1-C4alkyl). Pharmaceutically acceptable salts of an amino group include salts of: organic carboxylic acids such as acetic, lactic, tartaric, malic, lactobionic, fumaric, and succinic acids; organic sulfonic acids such as methanesulfonic, ethanesulfonic, isethionic, benzenesulfonic and p-toluenesulfonic acids; and inorganic acids such as hydrochloric, hydrobromic, sulfuric, phosphoric and sulfamic acids. Pharmaceutically acceptable salts of a compound having a hydroxyl group consist of the anion of said compound in combination with a suitable cation such as Na+, NH4+, or NR′4+(wherein R′ is for example a C1-4alkyl group).

The compounds of formula (1) have utility as exogenous receptor combining or complexing compounds, and may be used for binding with an opioid receptor. Further, the compounds may be used as a conjugate in an agonist/antagonist pair that is employed for transductional assay of neurotransmitter function in appertaining cellular or differentiated tissue systems, as well as for receptor assay, differential binding, and specificity applications for cellular, histological, and corporeal monitoring and assessment purposes.

The compounds of the above formula (1) exhibit specific bioactivity characteristics rendering them useful as therapeutic agents for treatment or prophylaxis of a wide variety of physiological and pathological conditions.

The compounds of formula (1) are particularly useful in mediating analgesia with reduced respiratory depression, as well as for the treatment of various disease states and physiological conditions, including, without limitation, diarrhea, cardiac disorders, cough, lung edema, gastrointestinal disorders, spinal injury, and drug addiction.

The compounds of formula (1) can be administered for therapeutic intervention in a pharmaceutical composition containing the compound and a pharmaceutically acceptable carrier. The invention contemplates the use of any means and/or of modality of administration of the compositions of the invention.

Compounds of the above general formula (1) exhibit binding selectivity for receptor(s). Depending on the structure and stereo-specificity of the particular formula (1) compounds, such compounds may exhibit binding ability to receptor(s) selected from the group consisting of delta receptors, mu receptors, kappa receptors, sigma receptors, and combinations of such receptors.

Various compounds within general formula (1) exhibit delta and mu receptor agonist activity. In the case of delta receptor agonists, activity is generally distinguished and measured by activity in the electrically stimulated mouse vas deferens assay, as well as in mouse brain assay involving the existence of a delta receptor subtype that is different from the delta receptor in the mouse vas deferens.

Various compounds within general formula (1) exhibit mu opioid receptor agonist activity. In the case of mu opioid receptor agonists, activity is generally distinguished and measured by activity in the electrically stimulated guinea pig ileum assay, as well as in rat brain assay involving the existence of a mu receptor subtype that is different from the mu receptor in the guinea pig ileum.

In consequence of the existence of delta receptor subtypes, other receptor binding assays or screening techniques may be employed as a further predictor of agonist or antagonist activity for specific compounds of the present invention.

In addition, to the extent that degeneration or dysfunction of opioid receptors is present or implicated in a disease state involving tissue or discrete cellular loci, isotopically labeled versions of the opioid compounds of the present invention may find utility in diagnostic and imaging applications, e.g., diagnostic techniques involving positron emission tomography (PET) scans of the brain.

For example, a method of diagnosis of degeneration or dysfunction of delta opioid receptors associated with a disease state or physiological condition involving tissue or discrete cellular loci comprising such receptors, may be carried out by administration of a labeled delta opioid receptor-binding compound to a subject to effect binding of the compound to the delta opioid receptors in the subject, followed by determination of the extent of binding of the compound to the delta opioid receptors in the subject, as diagnostic information for the diagnosis.

The opioid receptor-binding compound may for example be labeled by fluorescent, isotopic or reporter group labeling. In one preferred aspect, the extent of binding of the compound to the opioid receptors in the subject, is determined using positron emission tomography.

As used herein, in reference to the present invention, the term “alkyl” is intended to be broadly construed as encompassing: (i) alkyl groups of straight-chain as well as branched chain character; (ii) unsubstituted as well as substituted alkyl groups, wherein the substituents of substituted alkyl groups may include any sterically acceptable substituents which are compatible with such alkyl groups and which do not preclude the efficacy of the diarylmethylbenzylpiperazine or piperidine compound for its intended utility (examples of substituents for substituted alkyl groups include halogen (e.g., fluoro, chloro, bromo, and iodo), amino, amido, C1-C4alkyl, C1-C4alkoxy, nitro, hydroxy, etc.); (iii) saturated alkyl groups as well as unsaturated alkyl groups, the latter including groups such as alkenyl-substituted alkyl groups (e.g., allyl, methallyl, propallyl, butenylmethyl, etc.), alkynyl-substituted alkyl groups, and any other alkyl groups containing sterically acceptable unsaturation which is compatible with such alkyl groups and which does not preclude the efficacy of the diarylmethylbenzylpiperazine compound for its intended utility; and (iv) alkyl groups including linking or bridge moieties, e.g., heteroatoms such as nitrogen, oxygen, sulfur, etc.

As used herein, in reference to the present invention, the term “aryl” is intended to be broadly construed as referring to carbocyclic (e.g., phenyl, naphthyl) as well as heterocyclic aromatic groups (e.g., pyridyl, thienyl, furanyl, etc.) and encompassing unsubstituted as well as substituted aryl groups, wherein the substituents of substituted aryl groups may include any sterically acceptable substituents which are compatible with such aryl groups and which do not preclude the efficacy of the diarylmethylbenzylpiperazine compound for its intended utility. Examples of substituents for substituted aryl groups include one or more of halogen (e.g., fluoro, chloro, bromo, and iodo), amino, amido, C1-C4alkyl, C1-C4alkoxy, nitro, trifluoromethyl, hydroxy, hydroxyalkyl containing a C1-C4alkyl moiety, etc.

The compounds contemplated by the invention include those of formula (1) per se, as well as physiologically functional derivatives thereof.

By “physiologically functional derivative” is meant a pharmaceutically acceptable salt, ether, ester or salt of an ether or ester of the compound of formula (1) or any other compound which, upon administration to the recipient, is capable of providing (directly or indirectly) the said compound of formula (1) or an active metabolite or residue thereof. Phenolic C1-C6alkyl ethers are a sub-class of physiologically functional derivatives of the compounds of formula (1).

The compounds of the present invention may be readily synthesized within the skill of the art and in view of the illustrative synthetic examples hereinafter set forth.

The compounds of the invention when used in pharmaceutical or diagnostic applications desirably are prepared in a racemic mixture or an essentially pure enantiomer form, with an enantiopurity of at least 90% enantiomeric excess (EE), preferably at least 95% EE, more preferably at least 98% EE, and most preferably at least 99% EE. Enantiomeric excess values provide a quantitative measure of the excess of the percentage amount of a major isomer over the percentage amount of a minor isomer which is present therewith, and may be readily determined by suitable methods well-known and established in the art, as for example chiral high pressure liquid chromatography (HPLC), chiral gas chromatography (GC), nuclear magnetic resonance (NMR) using chiral shift reagents, etc.

Subjects to be treated by the methods of the present invention include both human and non-human animal (e.g., bird, dog, cat, cow, horse) subjects, and are preferably mammalian subjects, and most preferably human subjects.

Depending on the specific condition to be treated, animal subjects may be administered compounds of formula (1) at any suitable therapeutically effective and safe dosage, as may readily be determined within the skill of the art, and without undue experimentation.

In in vitro tests for agonist/antagonist activity, such as receptor binding affinity tests, and inhibition of electrically stimulated muscle twitch tests, compounds of the present invention exhibit potency over a range of from nanomolar to micromolar concentrations, depending on the specific compound employed.

In general, while the effective dosage of compounds of the invention for therapeutic use may be widely varied in the broad practice of the invention, depending on the specific application, condition, or disease state involved, as readily determinable within the skill of the art, suitable therapeutic doses of the compounds of the invention, for each of the appertaining compositions described herein, and for achievement of therapeutic benefit in treatment of each of the conditions described herein, will be in the range of 10 micrograms (μg) to 100 milligrams (mg) per kilogram body weight of the recipient per day, preferably in the range of 50 μg to 75 mg per kilogram body weight per day, and most preferably in the range of 100 μg to 50 mg per kilogram body weight per day. The desired dose is preferably presented as two, three, four, five, six, or more sub-doses administered at appropriate intervals throughout the day. These sub-doses may be administered in unit dosage forms, for example, containing from 10 μg to 1000 mg, preferably from 50 μg to 500 mg, more preferably from 50 μg to 250 mg, and most preferably from 50 μg to 10 mg of active ingredient per unit dosage form. Alternatively, if the condition of the recipient so requires, the doses may be administered as a continuous infusion.

The mode of administration and dosage forms will of course affect the therapeutic amounts of the compounds which are desirable and efficacious for the given treatment application.

For example, orally administered dosages typically are at least twice, e.g., 2-10 times, the dosage levels used in parenteral administration methods, for the same active ingredient. In oral administration, dosage levels for delta receptor binding compounds of the invention may be on the order of 5-200 mg/70 kg body weight/day. In tablet dosage forms, typical active agent dose levels are on the order of 10-100 mg per tablet.

The compounds of formula (1) may be administered per se as well as in the form of pharmaceutically acceptable esters, salts, and ethers, as well as other physiologically functional derivatives of such compounds.

The present invention also contemplates pharmaceutical formulations, both for veterinary and for human medical use, which comprise as the active agent one or more compound(s) of the invention.

In such pharmaceutical formulations, the active agent preferably is utilized together with one or more pharmaceutically acceptable carrier(s) therefor and optionally any other therapeutic ingredients. The carrier(s) must be pharmaceutically acceptable in the sense of being compatible with the other ingredients of the formulation and not unduly deleterious to the recipient thereof. The active agent is provided in an amount effective to achieve the desired pharmacological effect, as described above, and in a quantity appropriate to achieve the desired daily dose.

When the active agent is utilized in a formulation comprising a liquid solution, the formulation advantageously may be administered parenterally. When the active agent is employed in a liquid suspension formulation or as a powder in a biocompatible carrier formulation, the formulation may be advantageously administered orally, rectally, or bronchially.

When the active agent is utilized directly in the form of a powdered solid, the active agent may advantageously administered orally. Alternatively, it may be administered bronchially, via nebulization of the powder in a carrier gas, to form a gaseous dispersion of the powder which is inspired by the patient from a breathing circuit comprising a suitable nebulizer device.

In some applications, it may be advantageous to utilize the active agent in a “vectorized” form, such as by encapsulation of the active agent in a liposome or other encapsulant medium, or by fixation of the active agent, e.g., by covalent bonding, chelation, or associative coordination, on a suitable biomolecule, such as those selected from proteins, lipoproteins, glycoproteins, and polysaccharides.

The formulations comprising the active agent of the present invention may conveniently be presented in unit dosage forms and may be prepared by any of the methods well known in the art of pharmacy. Such methods generally include the step of bringing the active compound(s) into association with a carrier that constitutes one or more accessory ingredients. Typically, the formulations are prepared by uniformly and intimately bringing the active compound(s) into association with a liquid carrier, a finely divided solid carrier, or both, and then, if necessary, shaping the product into dosage forms of the desired formulation.

Formulations of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets, tablets, or lozenges, each containing a predetermined amount of the active ingredient as a powder or granules; or a suspension in an aqueous liquor or a non-aqueous liquid, such as a syrup, an elixir, an emulsion, or a draught.

A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine, with the active compound being in a free-flowing form such as a powder or granules which optionally is mixed with a binder, disintegrant, lubricant, inert diluent, surface active agent, or discharging agent. Molded tablets comprised of a mixture of the powdered active compound with a suitable carrier may be made by molding in a suitable machine.

A syrup may be made by adding the active compound to a concentrated aqueous solution of a sugar, for example sucrose, to which may also be added any accessory ingredient(s). Such accessory ingredient(s) may include flavorings, suitable preservative, agents to retard crystallization of the sugar, and agents to increase the solubility of any other ingredient, such as a polyhydroxy alcohol, for example glycerol or sorbitol.

Formulations suitable for parenteral administration conveniently comprise a sterile aqueous preparation of the active compound, which preferably is isotonic with the blood of the recipient (e.g., physiological saline solution). Such formulations may include suspending agents and thickening agents and liposomes or other microparticulate systems which are designed to target the compound to blood components or one or more organs. The formulations may be presented in unit-dose or multi-dose form.

Nasal spray formulations comprise purified aqueous solutions of the active compounds with preservative agents and isotonic agents. Such formulations are preferably adjusted to a pH and isotonic state compatible with the nasal mucous membranes.

Formulations for rectal administration may be presented as a suppository with a suitable carrier such as cocoa butter, hydrogenated fats, or hydrogenated fatty carboxylic acids.

Ophthalmic formulations are prepared by a similar method to the nasal spray, except that the pH and isotonic factors are preferably adjusted to match that of the eye.

Topical formulations comprise the active compound dissolved or suspended in one or more media, such as mineral oil, petroleum, polyhydroxy alcohols, or other bases used for topical pharmaceutical formulations.

Transdermal formulations may be prepared by incorporating the active agent in a thixotropic or gelatinous carrier such as a cellulosic medium, e.g., methyl cellulose or hydroxyethyl cellulose, with the resulting formulation then being packed in a transdermal device adapted to be secured in dermal contact with the skin of a wearer.

In addition to the aforementioned ingredients, formulations of this invention may further include one or more accessory ingredient(s) selected from diluents, buffers, flavoring agents, binders, disintegrants, surface active agents, thickeners, lubricants, preservatives (including antioxidants), and the like.

Methyl 3-formylbenzoate (10 g, 60.91 mmol, 1 eq), benzotriazole (7.25 g, 60.91 mmol, 1 eq) and (2S,5R)-1-allyl-2,5-dimethylpiperazine (Chirotech Division of Dow Pharmaceutical Services, Cambridge, UK, 9.39 g, 60.91 mmol, 1 eq) were placed in a flask with dry toluene (300 mL) and triethylamine (1 mL). The flask was fitted with a Dean-Stark trap and condenser and heated to a gentle reflux in an oil bath (temperature ≦135° C.) for several hours with azeotropic removal of water. Most of the toluene was removed under reduced pressure to give 28 g of crude 3-[(S)-((2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl)benzotriazol-1-yl-methyl]benzoic acid methyl ester as a dark amber viscous liquid.

(3-Iodo-phenoxy)-tert-butyl-dimethyl-silane (35.63 g, 106.6 mmol) was dissolved in THF (110 mL) at room temperature under nitrogen. Isopropylmagnesium chloride (2.0 M in THF, 53.3 mL, 106.6 mmol) was added dropwise through a dry addition funnel, and the reaction was stirred for an hour to give a pale yellow solution of 3-(tert-butyldimethylsilyloxy)phenyl magnesium iodide.

The freshly prepared benzotriazole adduct (28 g crude, ≦60.91 mmol, 1.0 eq) in THF (100 mL) was added via double ended needle to the above solution of Grignard reagent (1.75 eq) at room temperature under nitrogen and stirred overnight. The reaction was quenched with 12 mL of saturated ammonium chloride solution and stirred for 30 min at room temperature. The resulting suspension was filtered and solvent was removed under vacuum to give a viscous dark liquid. The residue was dissolved in ethyl acetate (700 mL) and washed with 10% sodium hydroxide solution (5×100 mL), water (4×100 mL) and brine (2×100 mL), and dried over sodium sulfate. Solvent was removed under reduced pressure to give a dark viscous residue (31.7 g). The residue was purified by chromatography on silica gel by eluting first with pentane/dichloromethane mixtures of 1:1, 1:2, and 1:4, followed successively by pure dichloromethane and 1.5% and 2% ethanol in dichloromethane, to give 26.9 g (86.8%) of 3-{(R)-((2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl)[3-(tert-butyl-dimethylsilanyloxy)phenyl]methyl}benzoic acid methyl ester.

A mixture of 3-{(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)[3-(tert-butyl-dimethylsilanyloxy)phenyl]methyl}benzoic acid methyl ester (7.4 g, 14.5 mmol) and 18.2 mL of 2.0 N aqueous sodium hydroxide (36.4 mmol, 2.5 eq) in THF (30 mL) was stirred overnight at room temperature. Hydrochloric acid (18.2 mL of 2 N aqueous solution) was added, and the THF was removed under vacuum. The aqueous residue was filtered to collect precipitated solid, which was washed with dichloromethane to remove organic impurities. The aqueous filtrate was concentrated to dryness to give additional solid material. The recovered solids were combined, washed with water to remove sodium chloride, and dried to give 5.5 g (99.4%) of crude 3-[(R)-((2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl)(3-hydroxyphenyl)methyl]benzoic acid (Acid A).

A mixture of 4-cyanobenzaldehyde (9.3 g), benzotriazole (8.45 g), 2R,5S-1-allyl-2,5-dimethylpiperazine (10.94 g), triethylamine (1 mL) and toluene (300 mL) in a round-bottom flask equipped with Dean-Stark trap (azeotropic removal of water) and reflux condenser was refluxed for 4 h under nitrogen. After cooling to room temperature, most of the solvent was removed under vacuum to give a viscous dark brown benzotriazole adduct.

Isopropylmagnesium chloride (124 mL of 2.0 M THF solution) was added to a solution of (3-iodo-phenoxy)-tert-butyl-dimethyl-silane (41.47 g, cf. procedure for Precursor Acid A) in THF (150 mL) at room temperature under nitrogen. The reaction was stirred at room temperature for 1 h to give a solution of 3-(tert-butyldimethylsilyloxy)phenyl magnesium iodide.

See Tables 1-6 for activity data.

Method A

Method B

4-[1,4]Diazepan-1-yl-propionic acid ethyl ester Na2CO3(2.94 g) was added to the solution of homopiperazine (13.88 g; 5.0 eq.) and ethyl 3-bromopropionate (5.02 g; 1 eq.) in CH3CN (100 mL). The reaction was stirred at room temperature for overnight. The reaction mixture was filtered thru a celite pad. The filtrate was concentrated. To the resulting residual water (200 mL) was added. The water solution was extracted by CHCl3(200 mL×3). The combined CH3Cl layer was washed by H2O (150 mL×2) and brine (150 mL×1), dried by Na2SO4 and concentrated to give 4-[1,4]diazepan-1-yl-propionic acid ethyl ester (3.49 g), which was carried on for the next step without further purification.1H NMR (300 MHz, CDCl3) δ 4.10 (m, 2H), 2.91-2.78 (m, 6H), 2.67 (m, 4H), 2.43 (m, 2H), 1.81 (bs, 1H), 1.72 (m, 2H), 1.23 (m, 3H).

Thionyl chloride (2.90 g) was added to the cloudy mixture of Acid A (6.63 g) in CH2Cl2(200 mL) at room temperature. The reaction was stirred at room temperature for 90 minutes while it was opened to air via a drying tube. The reaction solution became clear. The acid chloride solution was transferred into an additional funnel and then slowly added to a round bottom flask containing 4-[1,4]diazepan-1-yl-propionic acid ethyl ester (3.49 g) and triethylamine (3.88 g) in CH2Cl2(100 mL) at room temperature. The reaction was stirred at room temperature overnight while it was opened to air via a drying tube. The reaction was worked up by the addition of water (200 mL). Saturated NaHCO3solution was used to neutralize the H2O layer to pH≅8. The CH2Cl2layer and water layer were separated. The water layer was extracted by CH2Cl2(150 mL×3). The combined CH2Cl2layer was washed by H2O (150 mL×2) and brine (150 mL×1), dried by Na2SO4and concentrated to give crude product, which was purified by silica gel chromatography conducted on CombiFlash™ Sq 16× (gradient: 100% CH2Cl2to 10% MeOH in CH2Cl2) to give 3-(4-{3-[(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-[1,4]diazepan-1-yl)-propionic acid ethyl ester (4.2 g; 43%).

Thionyl chloride (1.76 g) was added to the cloudy mixture of Acid A (4.03 g) in CH2Cl2(250 mL) at room temperature. The reaction was stirred at room temperature for 45 minutes while it was opened to air via a drying tube. The reaction solution became clear light-brown solution. The acid chloride solution was transferred into an additional funnel and then slowly added to a round-bottom flask containing [1,4]diazepan-1-yl-acetic acid ethyl ester (1.79 g) and triethylamine (2.14 g) in CH2Cl2(100 mL) at 0° C. The reaction system was opened to air via a drying tube. After the addition of acid chloride solution, the cooling ice bath was removed and the reaction was stirred at room temperature for overnight. The reaction was quenched by the addition of water (150 mL). Saturated NaHCO3solution was used to neutralize the water layer to pH≅7. The CH2Cl2layer, turbid at this point, and water layer were separated. The CH2Cl2layer was washed by water (60 mL×2). All the above water layers were combined and extracted by EtOAc:MeOH=95:5 (120 mL×3). The CH2Cl2layer and EtOAc/MeOH layer were combined, dried by Na2SO4and concentrated to give crude product (4.9 g), which was purified by silica gel chromatography conducted on CombiFlash™ Sq 16× (gradient: 100% CH2Cl2to 10% MeOH in CH2Cl2) to give (4-{3-[(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-[1,4]diazepan-1-yl)-acetic acid ethyl ester (1.93 g; 37%).1H NMR (300 MHz, CDCl3) δ 7.53-7.22 (m, 4H), 7.08 (ddd, 1H, J=8.0, 8.0, 3.0 Hz), 6.61 (m, 3H), 5.88 (m, 1H), 5.20 (m, 3H), 4.17 (m, 2H), 3.82-3.68 (m, 2H), 3.47-3.32 (m, 5H), 2.95-2.80 (m, 4H), 2.77-2.50 (m, 5H), 2.15 (dd, 1H, J=10.0, 10.0 Hz), 1.97 (m, 2H), 1.75 (m, 1H), 1.27 (m, 3H), 1.15 (d, 3H, J=5.5 Hz), 1.00 (d, 3H, J=5.5 Hz); MS (FAB, glycerol) m/z: 549 (M++1), 395, 209, 153; Found C, 68.71; H, 7.97; N, 9.95. Calc.(C32H44N4O40.15 CH2Cl2) C, 68.78; H, 7.95; N, 9.98.

To the compound of Example 5 (330 mg) in THF (3 mL) was added 1N NaOH solution (1 mL). The reaction was stirred at room temperature for overnight. TLC of reaction mixture indicated the disappearance of starting material. The reaction solution was neutralized by the addition of 1 N HCl solution (1 mL). The mixture was put under rotary evaporator for the removal of THF.

Sodium carbonate (2.12 g) was added to the solution of homopiperazine (10.0 g; 5 eq.) and ethyl 4-bromobutyrate (3.90 g; 1 eq.) in CH3CN (120 mL). The reaction was stirred at room temperature for 6 h. The reaction mixture was filtered thru a celite pad. The filtrate was concentrated. The remaining residual was dissolved in CHCl3(120 mL), washed by H2O (50 mL×3) and brine (50 mL×1), dried by Na2SO4 and concentrated to give 4-[1,4]diazepan-1-yl-butyric acid ethyl ester (3.8 g), which was carried on for the next step without further purification.

Due to the low yield, all the water layers from the above work-up procedure were combined and extracted by n-butanol (100 mL×3). The n-butanol layers were combined and concentrated to give 750 mg of crude 4-(4-{3-[(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-[1,4]diazepan-1-yl)-butyric acid ethyl ester (indicated by1H NMR), which was treated by ester hydrolysis condition to afford the desired acid according to the following Example 8.

Thionyl chloride (1.26 g) was added to the cloudy mixture of Acid A (4.04 g) in CH2Cl2(200 mL) at room temperature. The reaction was stirred at room temperature for 75 minutes while it was opened to air via a drying tube. The reaction solution became clear light-brown solution. The acid chloride solution was transferred into an additional funnel and then slowly added to a round-bottom flask containing 5-[1,4]diazepan-1-yl-pentanoic acid ethyl ester (2.06 g) and N,N-diisopropylethylamine (2.75 g) in CH2Cl2(100 mL) at 0° C. The reaction system was opened to air via a drying tube. After the addition of acid chloride solution, the cooling ice bath was removed and the reaction was stirred at room temperature for overnight. The reaction was quenched by the addition of water (150 mL). Saturated NaHCO3solution was used to neutralize the water layer to pH≅8. The CH2Cl2layer and water layer were separated. The water layer was extracted by CH2Cl2(150 mL×3). The CH2Cl2layers were combined, washed by H2O (150 mL×2) and saturated NaCl solution (150 mL×1), dried by Na2SO4and concentrated to give crude product (2.6 g), which was purified by silica gel chromatography conducted on CombiFlash™ Sq 16× (gradient: 100% CH2Cl2to 10% MeOH in CH2Cl2) to give 5-(4-{3-[(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-[1,4]diazepan-1-yl)-pentanoic acid ethyl ester (1.20 g; 23%).1H NMR (300 MHz, CDCl3) δ 7.52 (m, 1H), 7.37-7.22 (m, 3H), 7.08 (m, 1H), 6.60 (m, 3H), 5.87 (m, 1H), 5.19 (m, 3H), 4.12 (q, 2H, J=7.0 Hz), 3.71 (m, 2H), 3.38 (m, 3H), 2.92-2.78 (m, 3H), 2.66-2.48 (m, 7H), 2.41 (m, 1H), 2.31 (m, 2H), 2.15 (dd, 1H, J=10.0, 10.0 Hz), 1.96 (m, 2H), 1.74 (m, 1H), 1.67-1.44 (m, 4H), 1.25 (t, 3H, J=7.0 Hz), 1.14 (d, 3H, J=5.5 Hz), 0.99 (d, 3H, J=6.0 Hz).

The following homopiperazine derivatives were synthesized by similar methods described for above homopiperazine derivatives.

Piperazine Derivatives

Acid A (2.00 g, 5.26 mmol) was weighed in a 250 mL, 3-necked round bottom flask and stirred under nitrogen in 150 mL of dichloromethane. A calcium chloride drying tube was placed on the flask. Thionyl chloride (0.54 mL, 7.36 mmol) was added to the cloudy mixture, followed by the addition of 2 drops of DMF. The mixture was stirred at room temperature for an hour and became a clear light brown solution.

The resulting acid chloride was poured into an addition funnel with a drying tube, which was fitted on the top of a round bottom flask containing ethyl 1-piperazine-carboxylate (4.62 mL, 31.54 mmol, 6 equiv.) and triethylamine (2.20 mL, 15.77 mmol) in 100 mL of dichloromethane. The acid chloride was added dropwise via the addition funnel to the amine solution over 1 hour. The mixture solution was allowed to stir at room temperature overnight. Water (200 mL) and saturated sodium hydrogencarbonate (100 mL) were added to the reaction solution and the two layers were separated. The water layer was extracted with dichloromethane (150 mL×3). The combined organic layer was washed with water (200 mL×3) and saturated sodium chloride solution (200 mL), dried over sodium sulfate, and the solvent was removed under vacuum. The crude material (4.85 g) was obtained as a dark pink liquid and was chromatographed on a Biotage silica gel column (32-63 μm, 60 A, cartridge Lot#40M1464-1) eluting first with dichloromethane to remove the less polar contaminant, then with 5% methanol in dichloromethane. The desired fractions were combined and the solvent was removed under reduced pressure to give 1.44 g (52%) of 4-{3-[(R)-((2S,5R)-4-allyl-2,5-dimethyl-piperazin-1-yl)(3-hydroxyphenyl)methyl]benzoyl}piperazine-1-carboxylic acid ethyl ester as a light yellow solid.

The allyl portion of the compound of Example 57 (5.76 g, 11.1 mmol) was removed using tris(triphenylphosphine)rhodium (I) chloride (1.18 g, 1.27 mmol) as follows. The reaction mixture in acetonitrile (80 mL) and water (20 mL) was heated under a gentle reflux and the solvent was allowed to distill off slowly. An additional volume of acetonitrile/water (4:1, 100 mL) was added with a rate such as to maintain a steady distillation. After the addition of solvent was completed, the distillation was continued until the volume was reduced to approximately 50 mL. The cooled solution was concentrated under reduced pressure. The residual dark brown solid was purified by chromatography on Biotage silica gel column (32-63 μm, 60 A, cartridge Lot#40S1614-1) eluting first with dichloromethane to remove the less polar contaminant, then using 5% methanol in dichloromethane with 1 mL of 50% NH4OH, then 10% methanol in dichloromethane. The desired fractions were combined and the solvent was removed under reduced pressure. The amine 4-{3-[(R)-((2S,5R)-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-piperazine-1-carboxylic acid ethyl ester was obtained as a yellow solid (3.88 g, 73%).

Piperazin-1-yl-acetic acid ethyl ester was made by the nucleophilic substitution between piperazine (5.0 g, 58.05 mmol) and ethyl bromoacetate (1.94 g, 11.61 mmol) in 60 mL of acetonitrile in the presence of sodium carbonate (6.15 g, 58.05 mmol). The crude yield was about 65%.

The allyl portion of the compound of Example 63 (6.97 g, 13.0 mmol) was removed using tris(triphenylphosphine)rhodium (I) chloride (1.39 g, 1.50 mmol) as follows. The reaction mixture in acetonitrile (80 mL) and water (20 mL) was heated under a gentle reflux and the solvent was allowed to distill off slowly. An additional volume of acetonitrile/water (4:1, 100 mL) was added with a rate such as to maintain a steady distillation. After the addition of solvent was completed, the distillation was continued until the volume was reduced to approximately 50 mL. The cooled solution was concentrated under reduced pressure. The residual dark brown solid was purified by chromatography on a Biotage silica gel column (32-63 μm, 60 A, cartridge Lot#40S1614-1) eluting first with dichloromethane to remove the less polar contaminant, then using 5% methanol in dichloromethane with 1 mL of 50% NH4OH, then 10% methanol in dichloromethane. The desired fractions were combined and the solvent was removed under reduced pressure to give (4-{3-[(R)-((2S,5R)-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-piperazin-1-yl)-acetic acid ethyl ester as a light yellow solid (4.68 g, 73%).

3-Piperazin-1-yl-propionic acid ethyl ester was made by nucleophilic substitution between piperazine (5.0 g, 58.05 mmol) and ethyl 3-bromopropionate (2.10 g, 11.61 mmol) in 60 mL of acetonitrile in the presence of sodium carbonate (6.15 g, 58.05 mmol). The crude yield was about 65%.

4-Piperazin-1-yl-butyric acid ethyl ester was made by nucleophilic substitution between piperazine (22.08 g, 256.33 mmol) and ethyl 4-bromobutyrate (10 g, 51.27 mmol) in 250 mL of acetonitrile in the presence of sodium carbonate (27.16 g, 256.33 mmol). The crude yield was about 69%.

The allyl portion of the compound of Example 74 (8.08 g, 14.4 mmol) was removed using tris(triphenylphosphine)rhodium (I) chloride (1.53 g, 1.65 mmol). The reaction mixture in acetonitrile (80 mL) and water (20 mL) was heated under a gentle reflux and the solvent was allowed to distil off slowly. Additional acetonitrile/water (4:1, 100 mL) was added at a rate such as to maintain a steady distillation. After the addition of solvent was completed, the distillation was continued until the volume was reduced to approximately 50 mL. The cooled solution was concentrated under reduced pressure. The residual dark brown solid was purified by chromatography on Biotage silica gel column (32-63 μm, 60 A, cartridge Lot#40S1614-1) eluting first with dichloromethane to remove the less polar contaminant, then using 5% methanol in dichloromethane with 1 mL of 50% NH4OH, then 10% methanol in dichloromethane. The desired fractions were combined and the solvent was removed under reduced pressure. The amine (4-{3-[(R)-((2S,5R)-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-piperazin-1-yl)-butyric acid ethyl ester (5.55 g, 74%) was obtained as a light yellow solid.

The compound of Example 77 (0.48 g) was hydrolized with 2.08 mL of 1 N NaOH solution in 4 mL of tetrahydrofuran. The reaction mixture was evaporated to dryness, 2 mL of water was added, and the resulting solution was extracted with 2×4 mL of EtOAc/Et2O to remove impurities. Hydrochloric acid (1.0 N, 2.08 mL) was added dropwise followed by several drops of 0.1N HCl to adjust pH to 6.0-6.5, and the aqueous solution was lyophilized overnight. The residue was redissolved in isopropanol and the solution was filtered to remove sodium chloride. Solvent was removed under vacuum. The residue was redissolved in water, lyophilized overnight, and dried in a vacuum oven (30 mmHg, 40° C.) to give 300 mg (66%) of white solid.

5-Piperazin-1-yl-pentanoic acid ethyl ester was made by nucleophilic substitution between piperazine (20.60 g, 239.1 mmol) and ethyl 5-bromovalerate (10.0 g, 47.8 mmol) in 250 mL of acetonitrile in the presence of sodium carbonate (25.35 g, 239.1 mmol). The crude yield was about 65%.

The ester of Example 83 (0.93 g) was hydrolyzed with 4.03 mL of 1 N NaOH solution in 5 mL of ethanol. The reaction mixture was evaporated to dryness, 2 mL of water was added, and the resulting solution was extracted with 2×4 mL of EtOAc/Et2O to remove impurities. Hydrochloric acid (1.0 N, 4.03 mL) was added dropwise followed by several drops of 0.1 N HCl to adjust pH to 6.0-6.5. The water layer was extracted by n-butanol (6 mL×3). The combined n-butanol layer was washed by water (10 mL), concentrated to give a yellow oil which was redissolved in acetone, concentrated under reduced pressure, redissolved in water, lyophilized overnight, and dried in a vacuum oven (30 mm Hg, 40° C.) to give 90 mg of the title compound.

The allyl portion of the compound of Example 83 (3.99 g, 6.92 mmol) was removed using tris(triphenylphosphine)rhodium (I) chloride (0.74 g, 0.80 mmol). The reaction mixture in acetonitrile (80 mL) and water (20 mL) was heated under a gentle reflux and the solvent was allowed to distill off slowly. Additional acetonitrile/water (4:1, 100 mL) was added with a rate such as to maintain a steady distillation. After the addition of solvent was completed, the distillation was continued until the volume was reduced to approximately 50 mL. The cooled solution was concentrated under reduced pressure. The amine 5-(4-{3-[(R)-((2S,5R)-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-piperazin-1-yl)-pentanoic acid ethyl ester was obtained as 4.66 g of a dark brown solid.

6-Piperazin-1-yl-hexanoic acid ethyl ester was made by the nucleophilic substitution between piperazine (19.31 g, 224.1 mmol) and ethyl 6-bromohexanoate (10.0 g, 44.8 mmol) in 250 mL of acetonitrile in the presence of sodium carbonate (23.75 g, 224.1 mmol). The crude yield was about 92%.

The allyl portion of the compound of Example 93 (11.60 g, 19.63 mmol) was removed using tris(triphenylphosphine)rhodium (I) chloride (2.09 g, 2.26 mmol). The reaction mixture in acetonitrile (144 mL) and water (36 mL) was heated under a gentle reflux and the solvent was allowed to distil off slowly. Additional acetonitrile/water (4:1, 180 mL) was added with a rate such as to maintain a steady distillation. After the addition of solvent was completed, the distillation was continued until the volume was reduced to approximately 50 mL. The cooled solution was concentrated under reduced pressure. The residual dark brown solid was purified by chromatography on Biotage silica gel column (32-63 μm, 60 A, cartridge Lot#40S1614-1) eluting first with dichloromethane to remove the less polar contaminant, then using 5% methanol in dichloromethane with 1 mL of 50% NH4OH, then 10% methanol in dichloromethane. The desired fractions were combined and the solvent was removed under reduced pressure. The amine 6-(4-{3-[(R)-((2S,5R)-2,5-dimethyl-piperazin-1-yl)-(3-hydroxy-phenyl)-methyl]-benzoyl}-piperazin-1-yl)-hexanoic acid ethyl ester was obtained as 7.37 g (68%) of a yellow solid.

The following piperazine derivatives were synthesized by similar methods described for above piperazine derivatives.

Thionyl chloride (0.93 g) was added to the cloudy mixture of Acid B (2.13 g) in CH2Cl2(150 mL) at room temperature. The reaction was stirred for 2 h while it was opened to air via a drying tube. At the end of 2 h, the reaction solution still had solid floating in the solution. Additional thionyl chloride (653 mg) was added to the reaction solution. The reaction was stirred for another 1 h. (Solid was still floating in the reaction solution.) The acid chloride solution was transferred into an addition funnel and then slowly added to a round-bottom flask containing 4-[1,4]diazepan-1-yl-butyric acid ethyl ester (1.2 g; cf. Example 7) and diisopropylethylamine (2.89 g) in CH2Cl2(100 mL) at room temperature. The reaction was stirred at room temperature overnight while it was opened to air via a drying tube. The reaction was quenched by the addition of water (150 mL). Saturated NaHCO3solution was used to neutralize the water layer to pH≅8. The CH2Cl2layer and water layer were separated. The water layer was extracted by CH2Cl2(150 mL×3). The CH2Cl2layers were combined, washed by H2O (150 mL×2) and saturated NaCl solution (150 mL×1), dried over Na2SO4, and concentrated to give crude product (2.5 g), which was purified by silica gel chromatography conducted on CombiFlash™ Sq 16×(gradient: 100% CH2Cl2to 10% MeOH in CH2Cl2) to give 4-(4-{4-[(R)-((2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl)(3-hydroxyphenyl)methyl]benzoyl}[1,4]diazepan-1-yl)butyric acid ethyl ester (752 mg; 23%).1H NMR (300 MHz, CDCl3) δ 7.40 (d, 2H, J=7.5 Hz), 7.27 (d, 2H, J=7.5 Hz), 7.09 (dd, 1H, J=8.0, 8.0 Hz), 6.63 (m, 3H), 5.88 (m, 1H), 5.27-5.12 (m, 3H), 4.09 (m, 2H), 3.73 (m, 2H), 3.43 (m, 3H), 2.98-2.79 (m, 3H), 2.67-2.42 (m, 8H), 2.30 (m, 2H), 2.19 (m, 1H), 2.02 (m, 1H), 1.93 (m, 1H), 1.75 (m, 3H), 1.22 (m, 3H), 1.13 (d, 3H, J=6.0 Hz), 1.03 (d, 3H, J=6.0 Hz).

Examples 126-133 were synthesized by similar methods described for above piperidine derivatives.

The title compound was synthesized from Acid A and 4-hydroxypiperidine by following the similar method described in Example 119.

Alternate Method: The piperidone ketal described above may also be prepared by making the acid chloride of Acid A (e.g. see Example 1) and reacting it with 1.2 equivalents of 1,4-dioxa-8-azaspiro-[4.5]decane and 1 equivalent of triethylamine. Purification can be accomplished as above.

Proline Derivative

Proline derivatives were synthesized from L-proline methyl ester hydrochloride and Acid A using the similar methods described above.

Sarcosine derivatives were synthesized from sarcosine ethyl ester hydrochloride and Acid A using similar methods described above.

Imidazole (18.15 g) was added to the solution of 2-(ethylamino)ethanol (9.14 g) in CH2Cl2(200 mL) at room temperature. The mixture was stirred for 10 minutes until all imidazole were dissolved. The solution was cooled in ice bath for 20 minutes. Chlorotriethylsilane (15.46 g) was added to the solution via a syringe. The solution was stirred under nitrogen for overnight, while it was warmed up to room temperature. The reaction solution was washed by H2O (150 mL×3), brine (150 mL×1), dried by Na2SO4and concentrated to give crude ethyl-(2-triethylsilanyloxy-ethyl)-amine (21.94 g), which was used in next step without further purification.1H NMR (300 MHz, DMSO-d6) □ 3.58 (t, 2H, J=6.0 Hz), 2.53 (m, 4H), 1.41 (s, 1H), 0.93 (m, 12H), 0.54 (q, 6H, J=8.0 Hz).

SOCl2(4.33 mL) was added to the mixture of 4-carboxybenzaldehyde (8.1 g) in toluene (150 mL), followed by the addition of DMF (0.5 mL). The reaction mixture was refluxed with a drying tube attached to the top of condenser. After being refluxed for 40 minutes, the reaction mixture became clear yellow solution. The reflux was continued for another 30 minutes. The reaction solution was cooled to room temperature and then to 0° C.

The solution of ethyl-(2-triethylsilanyloxy-ethyl)-amine (10.97 g) in CH2Cl2(70 mL) was cooled to 0° C. and then added via a syringe to the above acid chloride solution, followed by the addition of Et3N (8.19 g). The reaction was stirred under nitrogen for overnight, while it was warmed up to room temperature. The reaction mixture was poured into NaHCO3solution, which was prepared by mixing 1:1=H2O: saturated NaHCO3solution, followed by the addition of CH2Cl2(150 mL). The organic layer was separated by separate funnel, washed by H2O (120 mL×3) and brine (120 mL×1), dried by Na2SO4 and concentrated to give crude N-ethyl-4-formyl-N-(2-triethylsilanyloxy-ethyl)-benzamide (15.76 g).1H NMR (300 MHz, CDCl3) □ 10.04 (s, 1H), 7.91 (m, 2H), 7.55 (m, 2H), 3.91 (m, 1H), 3.62 (m, 3H), 3.35 (m, 2H), 1.08-1.28 (m, 3H), 0.94 (m, 9H), 0.58 (m, 6H).

The mixture of N-Ethyl-4-formyl-N-(2-triethylsilanyloxy-ethyl)-benzamide (3.58 g), (2R,5S)-1-(3-Fluoro-benzyl)-2,5-dimethyl-piperazine (2.61 g) and benzotriazole (1.4 g) in toluene (200 mL) was refluxed in a 3-neck round-bottom flask equipped with a soxhlet filled with molecule sieve under N2for 16 h. The reaction solution was cooled to room temperature under N2and then was added dropwise to the phenylmagnesium bromide (24 mL, 1 M THF solution) via an addition funnel under N2. The reaction was reacted under N2at room temperature for overnight. The reaction was quenched by the addition of saturated NH4Cl (6 mL) and H2O (90 mL). Two scoops of celite were added to the mixture. The resulting mixture was filtered through a celite pad. The reaction flask was rinsed by EtOAc (90 mL×1), which was also filtered through the celite pad.

Compounds of the present invention were evaluated for in vitro opioid receptor affinity in rat brain membranes (μ and δ opioid) and guinea pig cerebellum (κ opioid receptor). Membranes for radioligand binding were prepared from either rat whole brain or guinea pig cerebellum, supplied by Pel-Freeze Biological Inc. (Rogers, Ark.). Tissues were homogenized in 50 mM TRIS (Tris[hydroxymethyl]aminomethane) buffer (pH 7.4) containing 50 ug/ml soybean trypsin inhibitor, 1 mM EDTA (Ethylenediaminetetraacetic acid), and 100 μM PMSF (Phenylmethylsulfonyl fluoride). The homogenized brain tissues were centrifuged at 500×g for 30 minutes (4° C.) to remove large debris. The supernatant was polytronically sonicated for 10 seconds (P.E. setting of 2, 4° C.). Sucrose solution was then added to a final concentration of 0.35 M using a 10 mM TRIS-Sucrose buffer (pH 7.4) and the brain membranes were then centrifuged at 40,000×g for 30 minutes (4° C.). The membrane pellets were then washed twice in 10 mM TRIS buffer (pH 7.4) containing 50 μg/ml soybean trypsin inhibitor, 1 mM EDTA, and 100 μM PMSF.

For human opioid receptors, cell membranes, prepared from HEK-293 cells (Perkin Elmer product # 6110549) that expressed human delta receptor expressed or CHO cells (Perkin Elmer product # 6110535) that expressed human mu opioid receptor, were purchased from Perkin Elmer, Boston, Mass.

Radioligand binding assays were performed in 10 mM TRIS buffer (pH 7.4) containing protease inhibitors of 50 μg/ml soybean trypsin inhibitor, and 100 μM PMSF ( for brain membranes preparations only), 1 mM EDTA and 5 or 10 mM MgCl2. Tritium-labeled DAMGO (μ), Deltorphin II (δ), or U69593 (κ) purchased from New England Nuclear were used as ligands in competitive experiments (2-3×10−10M final concentrations) with non-specific binding defined by 0.5×10−6M Naloxone (purchased from SIGMA Chemical Co.). All binding assays were run at room temperature for 90 minutes and then terminated by rapid filtration on GF/C glass fiber filters (Whatman, Hillsboro, Oreg.) with 50 mM TRIS buffer (4° C., pH 7.4) employing a Brandel Semi-automatic Cell Harvester (Model M48, Brandel, Gaithersburg, Md.). The filters were washed twice with 50 mM TRIS buffer (4° C., pH 7.4) and the filters were placed in liquid scintillation cocktail and the bound radioactivity counted on a Beckman LS 6500 scintillation counter. The potency of the compounds in inhibiting the binding of radiolabelled DAMGO (μ), Deltorphin II (δ), or U69593 (κ) was determined from full concentration-effect curves. With the computer program Prism (GraphPad Software Inc., San Diego, Calif.) the IC50values were determined using a one-site nonlinear regression analysis of the radioligand binding data. The IC50values were then converted to Kivalues using the Cheng-Prusoff equation. (Cheng Y and Prusoff W H (1973) Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 percent inhibition (I50) of a enzymatic reaction. Biochem Pharm 22:3099-3108.)

Further the compounds of formula (1) were evaluated for in vitro opioid receptor activity in various receptor systems, including mouse vas deferens (Mouse Vas Deferens ED50), and guinea pig ileum (Guinea Pig Ileum ED50). The assay procedures used for such determinations of receptor activity are set out below.

In vitro bioassays: Mouse vasa deferentia (MVD), CD-1 strain, Harlan, Raleigh, N.C.) were removed from mice and suspended between platinum electrodes with 0.5 g of tension in organ bath chambers containing a modified Mg++free Krebs buffer of the following composition (millimolar): NaCl, 117.5; KCl, 4.75; CaCl2, 2.6; KH2PO4, 1.20; NaHCO3, 24.5; and glucose, 11. The buffer was saturated with 95% O2/5% CO2and kept at 37° C. Tissues were stimulated at supramaximal voltage with 10-Hz pulse trains for 400-msec.; train interval 10 seconds; and 1.0 msec pulse duration at maximal voltage. Delta receptor activity was determined by adding appropriate concentrations of test compound to organ baths and allowing a maximal response before addition of the next higher concentration. Mu receptor activity was determined in similar fashion, but in the presence of 3 □M TIPP (a highly selective delta antagonist; P. W. Schiller, T. M.-D. Nguyen, G. Weltrowska, B. C. Wilkes, B. J. Marsden, C. Lemieux, and N. N. Chung,Proc. Natl. Acad. Sci.89, 11871 (1992)) and 15 nM nor-BNI (a selective kappa antagonist; P. S. Portoghese, A. W. Lipkowski, and A. E. Takemori, Life Sci. 40, 1287 (1987)).

Intact ileums (about 3 cm length) were removed from guinea pig and suspended with 1 g of tension in a bath chamber as described for the vasa deferentia. The ileums were stimulated with electrical square-wave pulses of 0.1-Hz, 1 msec pulse duration at supramaximal voltage.

The percentage inhibition of the electrically induced muscle contractions was determined for the compounds at varying cumulative concentrations. The ED50values were extrapolated from curves showing the dose concentration plotted against the response (J. A. H. Lord, A. A. Waterfield, J. Hughes, H. W. Kosterlitz,Nature267, 495, (1977)).

Mouse Seizure-Like Convulsions and antinociception: The central (CNS) effects of the compound were tested with central delta receptor mediated seizure-like convulsions and central mu opioid receptor mediated antinociceptive effects in mice. Male CD-1 mice (Charles River, Raleigh, N.C.) weighing 20-25 g were used to determine the seizure-like convulsion and antinociception activities for compounds.

Each mouse received a single bolus dose of i.v. via the tail vein (10 mg/kg; n=10/dose). They were then observed for seizure-like convulsions for one hour following the treatment. A seizure-like event was recorded if a mouse had uncontrollable clonic (or tonic/clonic) muscle movements that encompassed its entire body, usually followed by a brief cataleptic period. Catalepsy was determined by placing the animal's front paws on a horizontal bar held 2-3 inches from the cage floor. Cataleptic animals made no attempt to remove their paws.

All mice received 10 mg/kg iv dose of compounds were also tested for the antinociceptive activity by a standard tail-pinch assay with an artery clamp. The test was performed by placing the artery clamp on the base of the tail. The clamp remained in place until an escape response occurred (i.e., tail-flick or vocalization or biting) or a maximum time of 20 seconds had elapsed. The normal response time to the pressure from the clamp is less than 1 second. Analgesic compounds like morphine at 4 mg/kg iv dose or fentanyl at 50 □g/kg iv dose will produce an antinociceptive effect with a maximum time of response of 20 seconds.

Tabulated empirical data for compounds of the invention are set out below in Tables 1-6 hereinafter set forth (Table 1=Homopiperazine Derivatives; Table 2=Piperazine Derivatives; Table 3=Piperidine Derivatives; Table 4=Proline Derivatives; Table 5=Sarcosine Derivatives; and Table 6=2-(Ethylamino)ethanol Derivatives).

While the invention has been described herein with reference to illustrative aspects, features and embodiments, it will be appreciated that the invention is not thus limited, but rather extends to and includes other variations, modifications and other embodiments, as will readily suggest themselves to those of ordinary skill in the art, based on the disclosure herein. Accordingly, the invention is intended to be interpreted and construed, as encompassing all such variations, modifications and other embodiments, as being within the spirit and scope of the claims as hereinafter set forth.