Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C217/00—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton
  • C07C217/54—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having etherified hydroxy groups bound to carbon atoms of at least one six-membered aromatic ring and amino groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings of the same carbon skeleton
  • C07C217/74—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having etherified hydroxy groups bound to carbon atoms of at least one six-membered aromatic ring and amino groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings of the same carbon skeleton with rings other than six-membered aromatic rings being part of the carbon skeleton
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/04—Centrally acting analgesics, e.g. opioids
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C217/00—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton
  • C07C217/52—Compounds containing amino and etherified hydroxy groups bound to the same carbon skeleton having etherified hydroxy groups or amino groups bound to carbon atoms of rings other than six-membered aromatic rings of the same carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C255/00—Carboxylic acid nitriles
  • C07C255/49—Carboxylic acid nitriles having cyano groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton
  • C07C255/58—Carboxylic acid nitriles having cyano groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton containing cyano groups and singly-bound nitrogen atoms, not being further bound to other hetero atoms, bound to the carbon skeleton
  • C07C255/59—Carboxylic acid nitriles having cyano groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton containing cyano groups and singly-bound nitrogen atoms, not being further bound to other hetero atoms, bound to the carbon skeleton the carbon skeleton being further substituted by singly-bound oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/02—Systems containing only non-condensed rings with a three-membered ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/14—The ring being saturated

Definitions

• the invention relates to tramadol analogs that are useful for the treatment of CNS- related disorders including pain, anxiety, depression and attention deficit disorder.
• Opioids such as morphine are very effective for the treatment of pain, but can result in very serious adverse effects, including respiratory depression, and addiction and dependency. Less serious side effects include gastrointestinal inhibition effects and obstipation. As a result, the use of such drugs is limited by the possibility of adverse effects. There is, therefore, a need for effective analgesics, which are not associated with these adverse effects.
• U.S. Patent No. 3,652,589, to Flick discloses a genus of phenol ethers, which are described as having analgesic properties.
• the genus includes 2-((dimethylamino)methyl)-l- (3-methoxyphenyl)-cyclohexanol), which has been given the name tramadol.
• the patent also discloses 3-benzyloxyphenyl analogues of tramadol.
• U.S. Patent No. 5.733,936 discloses tramadol analogs substituted at the 4-position of the cyclohexane ring.
• R 1 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl;
• R 2 is selected from hydrogen, hydroxy, cyano, haloalkyl, glycosyl, SO 2 R 5 , and OR 5 ;
• R 5 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl.
• alkyl is intended to include linear, branched, or cyclic hydrocarbon structures and combinations thereof.
• Lower alkyl refers to alkyl groups of from 1 to 4 carbon atoms. Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, s-and t-butyl. Preferred alkyl groups are those of C 2 o or below.
• Cycloalkyl is a subset of alkyl and includes cyclic hydrocarbon groups of from 3 to 8 carbon atoms.
• cycloalkyl groups include c-propyl, c-butyl, c-pentyl, and norbornyl
• Alkoxy or alkoxyl refers to groups of from 1 to 8 carbon atoms of a straight, branched, cyclic configuration and combinations thereof attached to the parent structure through an oxygen. Examples include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, and cyclohexyloxy. Lower alkoxy refers to groups containing one to four carbons.
• Acyl refers to groups of from 1 to 8 carbon atoms of a straight, branched, cyclic configuration, saturated, unsaturated and aromatic and combinations thereof, attached to the parent structure through a carbonyl functionality.
• One or more carbons in the acyl residue may be replaced by nitrogen, oxygen or sulfur as long as the point of attachment to the parent remains at the carbonyl. Examples include acetyl, benzoyl, propionyl, isobutyryl, t-butoxy- carbonyl, and benzyloxycarbonyl.
• Lower-acyl refers to groups containing one to four carbons.
• Arylalkyl means an alkyl residue attached to an aryl ring. Examples are benzyl and phenethyl.
• Heteroarylalkyl means an alkyl residue attached to a heteroaryl ring. Examples include, e.g., pyridinylmethyl, and pyrimidinylethyl.
• Heterocycle or heterocyclic means a cycloalkyl or aryl residue in which one to two of the carbons is replaced by a heteroatom such as oxygen, nitrogen or sulfur.
• heterocycles that fall within the scope of the invention include pyrrolidine, pyrazole, pyrrole, indole, quinoline, isoquinoline, tetrahydroisoquinoline, benzofuran, benzodioxan, benzodioxole (commonly referred to as methylenedioxyphenyl, when occurring as a substituent), tetrazole, morpholine, thiazole, pyridine, pyridazine, pyrimidine, thiophene, furan, oxazole, oxazoline, isoxazole, dioxane, and tetrahydrofuran.
• Haloalkyl refers to an alkyl residue, wherein one or more H atoms are replaced by halogen atoms; the term haloalkyl includes perhaloalkyl. Examples of haloalkyl groups that fall within the scope of the invention include CH 2 F, CHF 2 , and CF 3 .
• glycosyl means a sugar residue, attached through an ether linkage.
• glycosyl groups include glycosyl, fructosyl, mannosyl, and lactosyl.
• any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value.
• the amount of a component or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are expressly enumerated in this specification.
• one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate.
• the present invention relates to the genus of compounds of formula I:
• R 1 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl;
• R 2 is selected from hydrogen, hydroxy, cyano, haloalkyl, glycosyl, SO 2 R 5 , and OR 5 ;
• each conformational isomer may exist as one of a pair of enantiomers because two cliiral centers are present in the cyclohexane ring. Accordingly, each member of the genus includes two diasteromeric pairs or four individual enantiomers, designated (R,R)-, (S,S)-, (R,S) ⁇ , (S,R)-.
• the present invention relates to a subgenus of the compounds of formula I; the compounds of the subgenus have the structure of formula II:
• R 1 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl;
• R 2 is hydrogen or OR 1 ;
• R 3 and R 4 are independently selected from hydrogen and lower alkyl, or R 3 and R 4 taken together with the nitrogen atom form a five- or six-membered heterocyclic or substituted heterocyclic ring.
• the present invention particularly relates to several individual compounds of formula I/II.
• O-methyl tramadol R 1 , R 3 , and R 4 are each methyl, and R is methoxy.
• O-desmethyl O-methyl tramadol ODMOMT
• R , R 3 , and R 4 are each methyl, and R 2 is hydroxy.
• the structures of OMT and ODMOMT are shown below, with tramadol and its O-desmethyl metabolite for comparison.
• OMT, ODMOMT and the N- desmethyl analogs include both cis- and trans- isomers, all four enantiomers ((R,R)-, (S,S)-, (R,S)-, and (S,R)-) racemic mixtures thereof and racemic mixtures enriched to any degree in an enantiomer.
• OMT O-Desmethyl O-methyl- tramadol
• Compounds of formula I are useful for treating disorders modulated by opiate receptor activity and/or monoamine activity. Accordingly, the present invention relates to a method for such treatment, comprising administering to a mammal in need thereof a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof.
• the compound of formula I may be O-methyl tramadol or O-desmethyl O-methyl tramadol.
• the lack of opiate receptor activity and/or monoamine activity is a cause of the disorder or one or more of the biological manifestations, whether the activity was altered genetically, by infection, by irritation, by internal stimulus or by some other cause;
• opiate receptor activity and/or monoamine activity interferes with part of the biochemical or cellular cascade that results in or relates to the disease or disorder.
• the opiate receptor activity and/or monoamine activity alters the cascade, and thus controls the disease, condition or disorder.
• Disorders modulated by opiate receptor activity and/or monoamine activity include acute and chronic pain, affective disorders, including depression and anxiety, behavioral disorders, including attention deficit disorders, eating disorders, cerebral function disorders, substance abuse, sexual dysfunction, and urinary incontinence.
• the present invention also relates to a method for relieving acute and chronic pain.
• the method comprises administering to a mammal in need thereof a therapeutically effective amount of a compound of formula I or of a pharmaceutically acceptable salt thereof.
• OMT and/or ODMOMT may be administered.
• compounds of formula I are effective for the treatment of affective disorders.
• Affective disorders are defined as a group of disorders characterized by a disturbance of mood, accompanied by a full or partial manic or depressive symptom.
• the group includes, but is not limited to depression, anxiety disorders, bipolar disorder, chronic fatigue disorder, seasonal affective disorder, premenstrual syndrome, perimenopause, menopause and male menopause.
• Depression is characterized by changes in mood, and by feelings of intense sadness or pessimistic worry.
• Symptoms include insomnia, anorexia, mental slowing and loss of drive, enthusiasm, and libido.
• These disorders are additionally characterized in that increasing monoamine levels, especially norepinephrine, reduces symptoms.
• the present invention also relates to a method for treating affective disorders, including depression. The method comprises administering to a mammal in need thereof a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof.
• the compounds of formula I are also effective for treating behavioral disorders, which are defined as disorders affecting one's behavior resulting in inappropriate actions in learning and social situations.
• Behavioral disorders include attention deficit disorder (ADD).
• ADD attention deficit disorder
• the term ADD includes both attention deficit disorder and attention deficit disorder with hyperactivity (ADHD), and is used in accordance with its accepted meaning in the art. (See, for example, Diagnostic and Statistical Manual of Mental Disorders, Revised, Fourth Ed., (DSM-LU-R), American Psychiatric Assocation, 1997.)
• attention deficit disorder includes disruptive behavior disorder as characterized in DSM-IV-R as categories 314.xx (including 314.01, 314.00 and 314.9), 312.xx and 313.xx.
• Methylphenidate is typically the drug of choice for the treatment and/or prevention of ADD.
• Dextroamphetamine, tricyclic antidepressants, for example, imipramine, caffeine, and other psychostimulants such as pemoline and deanol, are less preferred alternatives to methylphenidate.
• Common side effects of methylphenidate include sleep disturbances, including insomnia, depression or sadness, headache, stomachache, suppression of appetite, elevated blood pressure, and, with large continuous doses, a reduction of growth. Accordingly, alternate means of treating or preventing attention deficit disorders would be of great benefit.
• the compounds of formula I are also effective for treating eating disorders. Eating disorders are defined as a disorder of one's appetite or eating habits or of inappropriate somatotype visualization. Eating disorders include bulimia, anorexia, obesity and cachexia.
• cerebral function disorder includes cerebral function disorders involving intellectual deficits such as senile dementia, Alzheimer's type dementia, memory loss, amnesia/amnestic syndrome, epilepsy, disturbances of consciousness, coma, lowering of attention, speech disorders, Parkinson's disease, Lennox syndrome, autism, hyperkinetic syndrome and schizophrenia. Also within the meaning of the term are disorders caused by cerebrovascular diseases including cerebral infarction, cerebral bleeding, cerbral arteriosclerosis, cerebral venous thrombosis, head injuries, and the like, where symptoms include disturbance of consciousness, senile dementia, coma, lowering of attention, and speech disorders.
• the compounds of formula I are also effective for treating substance abuse.
• substance abuse includes addiction to cocaine, heroin, nocotine, alcohol, anxiolytic and hypnotic drugs, cannabis (marijuana), amphetamines, hallucinogens, phenylcyclidine, volatile solvents, and volatile nitrites.
• Nicotine addiction includes nicotine addiction of all known forms, such as smoking cigarettes, cigars and/or pipes, and addiction to chewing tobacco.
• the compounds of formula I are also effective for treating sexual dysfunction (e.g., erectile dystunction and female sexual dysfunction).
• sexual dysfuntion as used herein, encompases male sexual dysfunction, or erectile dysfunction, and female sexual dysfunction, including orgasmic dysfunction related to clitoral disturbances.
• erectile dysfunction as used herein means an inability to achieve penile erection or ejaculation or both, or an inability to obtain or sustain an erection adequate for intercourse.
• the relative activity, potency and specificity of a compound of formula I in the treatment of sexual dysfunction can be assessed by determination of an IC 50 value, as described in U.S. Patent 5,656,629.
• cGMP-PDE and other PDE isozymes are isolated from cardiovascular tissues (heart and aorta) of various animal species and man by anion-exchange and affinity clromatography as described by Silver et al., Sec. Messeng. Phos., 13: 13-25 (1991)
• PDE activity in the presence and absence of test compounds is determined essentially as described by Thompson et al., Adv. Cyclic Nucleotide Res., 10:69-92.
• compounds are screened for their effect on cyclic nucleotide hydrolysis at 10 ⁇ M.
• the compounds of formula I are also effective for treating urinary incontinence, including, for example, bladder detrusor muscle instability incontinence, stress incontinence, urge incontinence, overflow incontinence, enuresis, and post-prostectomy incontinence.
• Urinary incontinence can be caused by uncontrolled or unstable bladder contractions, particularly of the bladder detrusor muscle, which serves to force fluids out of the bladder.
• Bladder detrusor muscle instability may result in, for example, stress incontinence or urge incontinence, or combinations thereof, and/or enuresis.
• the major proportion of the neurohumeral stimulus for physiologic bladder contraction is acetylcholine-induced stimulation of postganglionic muscarinic receptor sites on bladder smooth muscle.
• the present invention also relates to pharmaceutical compositions containing a therapeutically effective amount of one or more compounds of formula I, or a pharmaceutically acceptable salt thereof.
• a pharmaceutically acceptable carrier may also be included.
• Other therapeutic ingredients may also be included.
• pharmaceutically acceptable salts refer to salts prepared from pharmaceutically acceptable non-toxic acids including inorganic acids and organic acids.
• acids that form pharmaceutically acceptable salts with compounds of Formula I include acetic acid, benzenesulfonic (besylate) acid, benzoic acid, camphorsulfonic acid, citric acid, ethenesulfonic acid, fumaric acid, gluconic acid, glutamic acid, hydrobromic acid, hydrochloric acid, isethionic acid, lactic acid, maleic acid, malic acid, mandelic acid, methanesulfonic acid, mucic acid, nitric acid, pamoic acid, pantothenic acid, phosphoric acid, succinic acid, sulfuric acid, tartaric acid and j9-toluenesulfonic acid.
• hydrochloric acid salt is particularly preferred.
• Any suitable route of administration may be employed for providing the patient with an effective dosage of a compound of Formula I.
• oral, rectal, parenteral (including subcutaneous, intramuscular, and intravenous) routes may be employed.
• Dosage forms include tablets, troches, dispersions, suspensions, solutions, capsules and patches.
• the composition may be formulated for oral administration, and may be in the form of a tablet or capsule.
• compositions of the present invention may take a wide variety of forms, depending on the forms preparation desired for administration, for example, oral or parenteral (including intravenous).
• any of the usual pharmaceutical media may be employed, such as, water, glycols, oils, alcohols, flavoring agents, preservatives, and coloring agents in the case of oral liquid preparation, including suspension, elixirs and solutions.
• Carriers such as starches, sugars, microcrystalline cellulose, diluents, granulating agents, lubricants, binders and disintegrating agents may be used in the case of oral solid preparations such as powders, capsules and caplets, with the solid oral preparation being preferred over the liquid preparations.
• Preferred solid oral preparations are tablets or capsules, because of their ease of administration. If desired, tablets may be coated by standard aqueous or nonaqueous techniques. Oral and parenteral sustained release dosage forms may also be used.
• compositions may be conveniently presented in unit dosage form and prepared by any of the methods well known in the art of pharmacy.
• Preferred unit dosage formulations are those containing an effective dose, or an appropriate fraction thereof, of the active ingredient, or a pharmaceutically acceptable salt thereof.
• the magnitude of a prophylactic or therapeutic dose typically varies with the nature and severity of the condition to be treated and the route of administration. The dose, and perhaps the dose frequency, will also vary according to the age, body weight and response of the individual patient.
• the total daily dose ranges from about 10 mg per day to about 1000 mg per day, preferably about 20 mg per day to about 500 mg per day, and more preferably, about 50 mg per day to about 250 mg per day, in single or divided doses. It is further recommended that children, patients over 65 years old, and those with impaired renal or hepatic function, initially receive low doses and that the dosage be titrated based on individual responses and blood levels. It may be necessary to use dosages outside these ranges in some cases, as will be apparent to those in the art. Further, it is noted that the clinician or treating physician knows how and when to interrupt, adjust or terminate therapy in conjunction with individual patient's response.
• enantiomer is converted into another chemical entity by one of the separation procedures described above, a further step is typically required to liberate the desired enantiomeric form.
• specific enantiomer may be synthesized by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one enantiomer to the other by asymmetric transformation.
• Schemes 2 and 3 illustrate preparation of enantiomerically pure OMT and ODMOMT, starting from either enantiomerically pure cw-tramadol or from a racemic mixture of the (R,R)- and (S,S)- enantiomers.
• the hydroxy group at the 2-position of the cyclohexane ring of racemic tramadol, or one of its enantiomers is methylated to yield a mixture of the cis- and trar ⁇ -isomers of OMT.
• the cz ' s-isomer may be isolated by crystallization.
• Scheme 3 shows procedure for this synthesis of ODMOMT by demethylation of OMT (from Scheme 2) using Ph 2 PH and an alkyl lithium compound.
• Other cw-isomers of compounds of formula I may be synthesized from tramadol, using known procedures.
• N-Desmethyl tramadol analogs may be prepared in quantities suitable for continued research and biological testing, starting with racemic tramadol hydrochloride.
• the synthsis is illustrated schematically below; products are designated: 1) desmethyltramadol (DMT) 2) desmethyl-O-desmethyltramadol (DMODMT) 3) desmethyl-O-methyltramadol (DMOMT) and 4) desmethyl-O-desmethyl-O-methyltramadol (DMODMOMT).
• Tramado ⁇ HCI DMT DMODMT DMOMT DMODMOMT [0043] Tramadol hydrochloride is treated with aqueous potassium carbonate to provide racemic tramadol free-base. Tramadol hydrochloride is resolved with dibenzoyl tartrate to provide quantities of (R,R)- and (S ⁇ -tramadol.
• DMODMT Preparation of DMODMT is shown in Scheme 9. Tramadol free-base is N- demethylated with DEAD to provide DMT. The phenol functionality is then deprotected with DIBAL to provide DMODMT.
• DMODMOMT Preparation of DMODMOMT is shown in Scheme 10.
• the reactive nitrogen had to be first masked as the benzonium salt. This compound may then be methylated easily to provide the O-methyl framework. Removal of the N-benzyl group is effected with hydrogen gas over palladium to provide O- methyltramadol (OMT).
• OMT is demethylated with chloroethyl chloroformate to furnish DMOMT.
• the aryl-methyl ether is cleaved with LiPPh 2 and produced DMODMOMT.
• a IL 3 -neck RBF under argon was charged with l-Cyclohex-l-enyl-3-methoxy- benzene (8.0 g, 42.5 mmol).
• MCPBA meta-chloroperoxybenzoic acid
• a 10% aqueous solution of Na 2 S 2 O 3 300 mL was added to the reaction.
• the layers were separated. The organic layer was washed with 10% aqueous NaHCO 3 .
• Example 1.4 (£,S)-l-(3-Methoxy-phenyI)-7-oxa-bicyclo[4.1.0]heptane: [0051] A 500 mL 3-neck RBF under argon was charged with l-Cyclohex-l-enyl-3-methoxy- benzene (16.9 g, 90.0 mmol). To the flask was added 112 mL of MTBE, 4-phenyl pyridine N-oxide (3.08 g, 18 mmol), and (i?,i?)-Mn(salen) (1.71 g, 2.7 mmol).
• the HCI salt was prepared as follows: A 100 mL RBF under argon was charged with (+/-)-2-aminomethyl-l-(3-methoxy-phenyl)-cyclohexanol (0.95 g, 4.0 mmol). To the flask was added 20 mL of dry MTBE. 2N HCI (4.0 mL, 8.0 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.91 g (84%) of HCI salt.
• the HCI salt was prepared as follows. A 100 mL RBF under argon was charged with (+/-)-2-Dimethylaminomethyl-l-(3-methoxy-phenyl)-cyclohexanol (0.60 g, 2.28 mmol). To the flask was added 10 mL of dry MTBE. 2N HCI (2.28 mL, 4.56 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.64 g (94%) of HCI salt.
• the HCI salt was prepared as follows. A 100 mL RBF under argon was charged with (+/-)-trans-O-desmethyltramadol (1.0 g, 4.0 mmol). To the flask was added 10 mL of dry MTBE. 2N HCI (4.0 mL, 8.0 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide crude HCI salt. The crude HCI salt was dissolved in refluxing IP A (15 mL) and slowly allowed to cool to room temperature.
• the reaction mixture was quenched with 0.1N HCI (10 mL) at 0°C, and then poured into a separatory funnel containing EtOAc (300 mL) and 0.1N HCI (300 mL). The layers were separated. The EtOAc layer was dried (MgSO 4 ), filtered, and concentrated in vacuo to provide crude methyl ether. The crude product was chromatographed using 5% EtOAc/hexane to 10% EtOAc/hexane as eluent to provide 5.47 g (92%) of pure methyl ether.
• the fumaric acid salt was prepared as follows. (+/-)-tr ⁇ r ⁇ -O-Methyltramadol (0.37g, 1.35 mmol) was dissolved in 3 mL of methanol. To it at room temperature, was added a solution of fumaric acid (0.157 g, 1.35 mmol) in methanol (3 mL). The reaction mixture was stirred for 1 h. The solution was concentrated in vacuo to provide 0.53 g as a white foam (100%).
• the reaction stirred for 1 hour at 0°C, then warmed to reflux and stirred overnight. The next morning, the reaction was cooled to 0°C, and then was subsequently quenched with 3N HCI (20 mL). The layers were separated. The aqueous layer was washed with EtOAc (50 mL). The EtOAc layer was discarded. The aqueous layer was treated with solid K 2 CO 3 until pH>12. The aqueous layer was washed 3X with EtOAc (50 mL). The combined EtOAc layers were dried (MgSO 4 ), filtered, and concentrated in vacuo.
• Tramadol free-base (7.5g) was dissolved in toluene (20mL) and DEAD (6.4g) was added. The solution was heated at 55°C for 16h. The mixture was evaporated and diluted with EtOH (40 mL) and saturated aqueous ammonium chloride (40mL) and heated to reflux (110°C, bath) for 2h. The mixture was again evaporated to an oily solid. The residue was dissolved in aqueous base (20 mL 10%> K 2 CO 3 and 60mL H 2 O) and extracted with ethyl acetate. The organic extracts were evaporated to yield a yellow solid (13.36g).
• the yellow solid was dissolved in ethyl acetate and washed with 10% aqueous K 2 CO 3 .
• the organic layer was evaporated to yield an oily solid (9.5g).
• the residue was chromatographed with a small amount of silica. Elution with an ethyl acetate/hexanes gradient yielded a clear oil (8.03g). This oil could be crystallized from hot hexanes (20mL) overnight to yield OMT (5.25g) as white cubes.
• OMT (4.0g, 14.41mmol) was dissolved in DCE (40mL) and to it was added 1 -chloroethyl chloroformate (2.3mL, 1.5eq). The mixture was heated at 90°C for 4h before being evaporated to dryness. The residue was dissolved in anhydrous methanol (80mL) and further heated at reflux (90°C, bath) for 2h. Evaporation yielded the crude DMOMT as the hydrochloride salt. Chromatography was difficult due to tailing and acid-exchange but yielded 4.3g of the amine in various forms.
• Example 1.42 Rac-O-Desmethyl-O-Cyclopropylethyltramadol: [00102] A dry 2-neck flask equiped with a reflux condenser was charged with anhydrous THF (6 mL) and diphenyl phosphine (469 ⁇ L, 8.1 mmol). The clear solution was cooled to -10 °C and ⁇ -BuLi (2.5 M solution in hexane, 1.3 mL, 3.24 mmol) was added dropwise.
• aqueous phase was brought up to pH 12 with K 2 CO 3 , washed with EtOAc (3 X 30 mL), and the combined organic extracts were dried (Na 2 SO 4 ), filtered and concentrated. Purification by silica gel column chromatography with 90/9/1 CH 2 Cl 2 /MeOH/conc. NH 4 OH yielded rac- O-desmethyl-O-cyclopropylethyltramadol as an off white solid. An analytical sample was prepared by PTLC using a 1 cm plate and 20% MeOH/CH 2 Cl 2 .
• a dry 2-neck flask equiped with a reflux condenser was charged with anhydrous THF (25 mL) and diphenyl phosphine (2.0 mL, 11.5 mmol).
• the clear solution was cooled to -10 °C and «-BuLi (2.5 M solution in hexane, 5.5 mL, 13.8 mmol) was added dropwise.
• the resultant bright orange solution was stirred for 30 min at -10 °C, then O- butyltramadol (815 mg, 2.55 mmol) in anhydrous THF (15 mL) was added dropwise.
• Diastereomer A Diastereomer B
• Diastereomer A (36 mg, 0.046 mmol) and 10% wt. Pd/C (50 mg) were suspended in 10: 1 MeOH:H O (3.3 mL) in a 30 mL hydrogenation bomb. A stir bar was added, and the vessel was purged 3 times with H 2 then charged to 50 psi. After 17 hours the suspension was diluted with MeOH (3 mL) and filtered through celite. The celite was washed with MeOH and the combined washes concentrated to give 15 mg (79%) of product as an orange/whitish solid.
• Flash chromatography was performed on EM Science silica gel 60. Thin layer chromatography was performed using silica gel 60 F 254 plates, and compound visualization was effected with 10% H 2 SO containing 5% ammonium molybdate and 0.2% eerie sulfate. All reactions were carried out in oven-dried glassware under an argon atmosphere. 1H NMR and C NMR were performed on a 300 MHz Varian instrument. TMS and CDCI 3 were used as internal standards for 1H and 13 C spectra, respectively. J values are given in hertz.
• Example 1.48 (+/-)-(2-Methoxy-2-phenyl-cyclohexylmethyl)-dimethyl-amine HCI: [00109] To a magnetically stirred solution of (+/-)-trifluoro-methanesulfonic acid 3-(2- dimethylaminomethyl-l-methoxy-cyclohexyl)-phenyl ester (0.48 g, 1.21 mmol) in anhydrous DMF (2.42 mL) at room temperature under Ar atmosphere were added successively TEA (0.449 mL, 3.63 mmol), triphenylphosphine (12.6 mg, 0.048 mmol), Pd(OAc) 2 (5.4 mg, 0.0242 mmol), and formic acid (0.091 mL, 2.42 mmol).
• the HCI salt was prepared as follows. To a 50 mL RBF under argon was charged with (+/-)-(2-Methoxy-2-phenyl-cyclohexylmethyl)-dimethyl-amine (0.251 g, 1.01 mmol). To the flask was added 5 mL of dry MTBE. 2N HCI (0.80 mL, 1.60 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.22 g (77%) of HCI salt.
• the HCI salt was prepared as follows. To a 50 mL RBF under argon was charged with (li?,2i?)-(2-methoxy-2-phenyl-cyclohexylmethyl)-dimethyl-amine (0.27 g, 1.09 mmol). To the flask was added 5 mL of dry MTBE. 2N HCI (0.80 mL, 1.60 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.20 g (64%>) of HCI salt.
• the HCI salt was prepared as follows. To a 50 mL RBF under argon was charged with (l 1 S',25)-(2-methoxy-2-phenyl-cyclohexylmethyl)-dimethyl-amine (0.255 g, 1.01 mmol). To the flask was added 5 mL of dry MTBE. 2N HCI (0.80 mL, 1.60 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.24 g (82%o) of HCI salt.
• the HCI salt was prepared as follows. To a 50 mL RBF under argon was charged with (+/-)-3-(2-Dimethylaminomethyl-l-methoxy-cyclohexyl)-benzonitrile (0.25 g, 0.091 mmol). To the flask was added 5 mL of dry MTBE. 2N HCI (0.80 mL, 1.60 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.196 g (70%) of HCI salt. *H NMR
• the HCI salt was prepared as follows. To a 50 mL RBF under argon was charged with (+/-)-3-(l-Methoxy-2-methylaminomethyl-cyclohexyl)-benzonitrile (0.10 g, 0.038 mmol). To the flask was added 5 mL of dry MTBE. 2N HCI (0.38 mL, 0.76 mmol) was added dropwise at room temperature. After stirring for 1 hour at room temperature, the white precipitate was filtered in vacuo to provide 0.08 g (91%) of HCI salt.
• ODMT is referred to as the Ml metabolite in some literature references.
• the (i?,i?)-enantiomer of ODMT is believed to be responsible for the opioid component of the tramadol analgesic effect, based on its in vivo affinity for the ⁇ receptor, which is much greater than that of either enantiomer of tramadol.
• ODMT O-desmethyl metabolite
• Radioactivity was determined with a scintillation counter (Topcount, Packard) using a liquid scintillation cocktail (Microscint 0, Packard).
• the specific radioligand binding to the receptors is defined as the difference between total binding and nonspecific binding determined in the presence of an excess of unlabelled ligand. Results are expressed as a percent of control values and as a percent inhibition of control values obtained in the presence of the test compounds.
• IC 50 values concentration causing a half-maximal inhibition of control values
• Hill coefficients nH were determined by non-linear regression analysis of the inhibition curves. These parameters were obtained by Hill equation curve fitting.
• the IC5 0 values obtained for the reference compounds are within accepted limits of historic averages obtained ⁇ 0.5 log units. Results are shown in Table 1.
• ODMT O-desmethyltramadol
• OMT O-methyl tramadol
• ODMOMT O-desmethyl O-methyl tramadol
• NDMOMT is the di- N-desmethyl derivative of OMT.
• Affinity of (i?,i?)-ODMOMT, (£S)-ODMOMT, and racemic ODMOMT for the ⁇ receptor was comparable to the corresponding enantiomer/racemate of ODMT, and much greater than that of racemic tramadol. Even more surprisingly, affinity of the same ODMOMT enantiomers and of the racemate for the K and ⁇ receptors was greater than that of the corresponding ODMT enantiomers and of the racemate, indicating that ODMOMT has utility as an analgesic.
• the table also shows that racemic OMT and (S,S)- and racemic ODMOMT were more effective at blocking NE uptake than racemic tramadol or (S, S) -ODMT.
• Cis- and trans- isomers of OMT (racemic) and (R,R)- and (S,S)-OMT were more effective at blocking at 5-HT uptake than racemic tramadol, (R,R)- or or racemic ODMT.
• Table 2 provides the ingredients for a lactose-free tablet dosage form of a compound of formula I:
• the active ingredient is blended with the cellulose until a uniform blend is formed.
• the smaller quantity of cornstarch is blended with a suitable quantity of water to form a corn starch paste. This is then mixed with the uniform blend until a uniform wet mass is formed. The remaining cornstarch is added to the resulting wet mass and mixed until uniform granules are obtained.
• the granules are then screened through a suitable milling machine, using a l A inch stainless steel screen.
• the milled granules are then dried in a suitable drying oven until the desired moisture content is obtained.
• the dried granules are then milled through a suitable milling machine using l A mesh stainless steel screen.
• the magnesium stearate is then blended and the resulting mixture is compressed into tablets of desired shape, thickness, hardness and disintegration. Tablets are coated by standard aqueous or nonaqueous technique.
• Tablets of other strengths may be prepared by altering the ratio of active ingredient to pharmaceutically acceptable carrier, the compression weight, or by using different punches.

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