WO2005019222A1 - 4-cycloalkylaminopyrazolo pyrimidine nmda/nr2b antagonists - Google Patents
4-cycloalkylaminopyrazolo pyrimidine nmda/nr2b antagonists Download PDFInfo
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- WO2005019222A1 WO2005019222A1 PCT/US2004/025979 US2004025979W WO2005019222A1 WO 2005019222 A1 WO2005019222 A1 WO 2005019222A1 US 2004025979 W US2004025979 W US 2004025979W WO 2005019222 A1 WO2005019222 A1 WO 2005019222A1
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- 0 **OC(CC1)CCC1Nc1ncnc2c1cn[n]2 Chemical compound **OC(CC1)CCC1Nc1ncnc2c1cn[n]2 0.000 description 5
- OSKYRIPJCNWXQP-UHFFFAOYSA-N C(COC1CCC(CNc2c(cn[nH]3)c3ncn2)CC1)c1ccccc1 Chemical compound C(COC1CCC(CNc2c(cn[nH]3)c3ncn2)CC1)c1ccccc1 OSKYRIPJCNWXQP-UHFFFAOYSA-N 0.000 description 1
- XGWAEJXSBLBFQE-FNARNRNOSA-N COC(/C=C/c1ccccc1)=N Chemical compound COC(/C=C/c1ccccc1)=N XGWAEJXSBLBFQE-FNARNRNOSA-N 0.000 description 1
- DJARJNRIGPBHMR-ZHACJKMWSA-N N=C(/C=C/c1ccccc1)NCc(cccc1)c1O Chemical compound N=C(/C=C/c1ccccc1)NCc(cccc1)c1O DJARJNRIGPBHMR-ZHACJKMWSA-N 0.000 description 1
- KPRZOPQOBJRYSW-UHFFFAOYSA-N NCc(cccc1)c1O Chemical compound NCc(cccc1)c1O KPRZOPQOBJRYSW-UHFFFAOYSA-N 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
- C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
- C07D487/04—Ortho-condensed systems
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- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
Compounds represented by Formula (I): (where R1 and Y are defined herein) or pharmaceutically acceptable salts thereof, are effective as NMDA/NR2B antagonists useful for treating neurological conditions such as, for example, pain, Parkinson’s disease, Alzheimer’s disease, epilepsy, depression, anxiety, ischemic brain injury including stroke, and other conditions.
Description
SUMMARY OF THE INVENTION The present invention relates to 4-cycloalkylaminopyrazolo pyrimidine compounds represented by Formula (la):
(la)
(where R1 and Y are as defined herein) or pharmaceutically acceptable salts thereof. The present invention also provides pharmaceutical compositions comprising the instant compounds. This invention further provides methods to treat and prevent neurological conditions, including pain, Parkinson's disease, Alzheimer's disease, epilepsy, depression, anxiety, ischemic brain injury including stroke, and other conditions, utilizing the present compounds and compositions.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of this invention are represented by Formula (la):
(la)
wherein: - 2
Rl is
, unsubstituted or substituted with halogen or -R2, where R2 is Cι_ 6alkyl, independently unsubstituted or substituted with one or more halogen;
Y is -Ci-6alkyl, independently unsubstituted or substituted with one or more halogen;
and pharmaceutically acceptable salts thereof and individual enantiomers and diastereomers thereof. As used herein, "alkyl" as well as other terms having the prefix "alk" such as, for example, alkoxy, alkanoyl, alkenyl, alkynyl and the like, means carbon chains which may be linear or branched or combinations thereof. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec- and tert-butyl, pentyl, hexyl, heptyl and the like. The term "aryl", unless specifically stated otherwise, includes optionally substituted multiple and single ring systems such as, for example, phenyl, naphthyl and tolyl. In the structures depicted throughout this application a hydrogen atom on an unsubstituted nitrogen atom may be either expressly shown or implicit. For example, the Formula la structure depicted above (with hydrogen atoms at two of the nitrogen atoms) may also be depicted as:
Thus, substitution can be made at any of the groups. For example, substituted aryl(Cι-6)alkyl includes substitution on the aryl group as well as substitution on the alkyl group. Compounds described herein may contain one or more asymmetric centers and may thus give rise to diastereomers and optical isomers. The present invention includes all such possible diastereomers as well as their racemic mixtures, their substantially pure resolved enantiomers, all possible geometric isomers, and pharmaceutically acceptable salts thereof. Formula la is shown without a definitive stereochemistry at certain positions. The present invention includes all stereoisomers of Formula la and pharmaceutically acceptable salts thereof. Further, mixtures of stereoisomers as well as isolated specific stereoisomers are also included. During the course of the synthetic procedures used to prepare such compounds, or in using racemization or epimerization procedures known to those skilled in the art, the products of such procedures can be a mixture of stereoisomers. The independent syntheses of these diastereomers or their chromatographic separations may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry may be determined by the x-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of lαiown absolute configuration. If desired, racemic mixtures of the compounds may be separated so that the individual enantiomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the
added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art. Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art. As used herein, "pharmaceutically acceptable salts" refer to derivatives wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts include the conventional non-toxic salts or the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, and the like. When the compound of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p- toluenesulfonic acid, and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, fumaric, and tartaric acids. It will be understood that, as used herein, references to the compounds of Formula la are meant to also include the pharmaceutically acceptable salts. The term "pharmaceutically acceptable salts" refers to salts prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include, for example, acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, and tartaric acids.
5 -
The subject treated in the present methods is generally a mammal, preferably a human being, male or female, in whom antagonism of CGRP receptor activity is desired. The term "therapeutically effective amount" means the amount of the subject compound that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician. As used herein, the term "treatment" refers both to the treatment and to the prevention or prophylactic therapy of the mentioned conditions, particularly in a patient who is predisposed to such disease or disorder. The term "composition" as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. Such term in relation to pharmaceutical composition, is intended to encompass a product comprising the active ingredient(s), and the inert ingredient(s) that make up the carrier, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By "pharmaceutically acceptable" it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. The terms "administration of and or "administering a" compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual in need of treatment. The pharmaceutical compositions of the present invention comprise a compound represented by Formula la (and/or pharmaceutically acceptable salt(s) thereof) as an active ingredient, a pharmaceutically acceptable carrier, and, optionally, other therapeutic ingredients or adjuvants. The instant compositions include those suitable for oral, rectal, topical, and parenteral (including subcutaneous, intramuscular, and intravenous) administration, although the most suitable route in any given case will depend on the particular host, and nature and severity of the conditions for which the active ingredient is being administered. The pharmaceutical compositions may be conveniently presented in unit dosage form and prepared by any of the methods well known in the art of pharmacy. The present invention is further directed to a method for the manufacture of a medicament for the antagonism of NMDA/NR2B receptor activity in humans and animals
comprising combining a compound of the present invention with a pharmaceutical carrier or diluent. In practice, the compounds represented by Formula la, or pharmaceutically acceptable salts thereof, of this invention can be combined as the active ingredient in intimate admixture with a pharmaceutical carrier according to conventional pharmaceutical compounding techniques. The carrier may take a wide variety of forms depending on the form of preparation desired for administration, e.g., oral or parenteral (including intravenous). Thus, the pharmaceutical compositions of the present invention can be presented as discrete units suitable for oral administration such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient. Further, the compositions can be presented as a powder, as granules, as a solution, as a suspension in an aqueous liquid, as a non-aqueous liquid, as an oil- in-water emulsion or as a water-in-oil liquid emulsion. In addition to the common dosage forms set out above, the compound represented by Formula la, and/or pharmaceutically acceptable salt(s) thereof, may also be administered by controlled release means and/or delivery devices. The compositions may be prepared by any of the methods of pharmacy. In general, such methods include a step of bringing into association the active ingredient with the carrier that constitutes one or more necessary ingredients. In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both. The product can then be conveniently shaped into the desired presentation. Thus, the pharmaceutical compositions of this invention may include a pharmaceutically acceptable carrier and a compound or a pharmaceutically acceptable salt of Formula la. The compounds of Formula la, or pharmaceutically acceptable salts thereof, can also be included in pharmaceutical compositions in combination with one or more other therapeutically active compounds. The pharmaceutical carrier employed can be, for example, a solid, liquid, or gas.
Examples of solid carriers include lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, and stearic acid. Examples of liquid carriers are sugar syrup, peanut oil, olive oil, and water. Examples of gaseous carriers include carbon dioxide and nitrogen. In preparing the compositions for oral dosage form, any convenient pharmaceutical media may be employed. For example, water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents and the like may be used to form oral liquid preparations such as suspensions, elixirs and solutions; while carriers such as starches, sugars, microcrystalline cellulose, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like may be used to form oral solid preparations such as powders, capsules and tablets. Because of their ease of administration, tablets and capsules are the preferred oral dosage units - 7 -
whereby solid pharmaceutical carriers are employed. Optionally, tablets may be coated by standard aqueous or nonaqueous techniques A tablet containing the composition of this invention may be prepared by compression or molding, optionally with one or more accessory ingredients or adjuvants. Compressed tablets may be prepared by compressing, in a suitable machine, the active ingredient in a freerflowing form such as powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active or dispersing agent. Molded tablets may be made by molding in a suitable machine, a mixture of the powdered compound moistened with an inert liquid diluent. Each tablet preferably contains from about 0.5mg to about 5g of the active ingredient and each cachet or capsule preferably containing from about 0.5mg to about 5g of the active ingredient. The pharmaceutical compositions of the present invention comprise a compound represented by Formula la (or pharmaceutically acceptable salts thereof) as an active ingredient, a pharmaceutically acceptable carrier, and optionally one or more additional therapeutic agents or adjuvants. The instant compositions include compositions suitable for oral, rectal, topical, and parenteral (including subcutaneous, intramuscular, and intravenous) administration, although the most suitable route in any given case will depend on the particular host, and nature and severity of the conditions for which the active ingredient is being administered. The pharmaceutical compositions may be conveniently presented in unit dosage form and prepared by any of the methods well known in the art of pharmacy. Pharmaceutical compositions of the present invention suitable for parenteral administration may be prepared as solutions or suspensions of the active compounds in water. A suitable surfactant can be included such as, for example, hydroxypropylcellulose. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof in oils. Further, a preservative can be included to prevent the detrimental growth of microorganisms. Pharmaceutical compositions of the present invention suitable for injectable use include sterile aqueous solutions or dispersions. Furthermore, the compositions can be in the form of sterile powders for the extemporaneous preparation of such sterile injectable solutions or dispersions. In all cases, the final injectable form must be sterile and must be effectively fluid for easy syringability. The pharmaceutical compositions must be stable under the conditions of manufacture and storage; thus, preferably should be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g. glycerol, propylene glycol and liquid polyethylene glycol), vegetable oils, and suitable mixtures thereof. Pharmaceutical compositions of the present invention can be in a form suitable for topical use such as, for example, an aerosol, cream, ointment, lotion, dusting powder, or the - 8 -
like. Further, the compositions can be in a form suitable for use in transdermal devices. These formulations may be prepared, utilizing a compound represented by Formula la of this invention, or pharmaceutically acceptable salts thereof, via conventional processing methods. As an example, a cream or ointment is prepared by mixing hydrophilic material and water, together with about 5 wt% to about 10 wt% of the compound, to produce a cream or ointment having a desired consistency. Pharmaceutical compositions of this invention can be in a form suitable for rectal administration wherein the carrier is a solid. It is preferable that the mixture forms unit dose suppositories. Suitable carriers include cocoa butter and other materials commonly used in the art. The suppositories may be conveniently formed by first admixing the composition with the softened or melted carrier(s) followed by chilling and shaping in moulds. In addition to the aforementioned carrier ingredients, the pharmaceutical formulations described above may include, as appropriate, one or more additional carrier ingredients such as diluents, buffers, flavoring agents, binders, surface-active agents, thickeners, lubricants, preservatives (including anti-oxidants) and the like. Furthermore, other adjuvants can be included to render the formulation isotonic with the blood of the intended recipient. Compositions containing a compound described by Formula la, and/or pharmaceutically acceptable salts thereof, may also be prepared in powder or liquid concentrate form. The utility of the compounds in accordance with the present invention as antagonists of NMDA/NR2B receptor activity may be demonstrated by methodology known in the art. Inhibition of the binding to NMDA receptors and functional antagonism of calcium efflux through NMDA channels were determined as follows: Cell-Based Functional Assay To Determine IC50 of NR2B Antagonists
The ability of selected compounds to inhibit NRlaNR2B NMDA receptor, as measured by NRla/NR2B receptor-mediated Ca2+ influx, was assessed by the following calcium flux assay procedure: NRla/NR2B receptor transfected L(tk-) cells were plated in 96-well format at 3 x 104 cells per well and grown for one to two days in normal growth medium (Dulbeccos MEM with Na pyruvate, 4500 mg glucose, pen/strep, glutamine, 10% FCS and 0.5 mg/mL geneticin). NRla NR2B-expression in these cells was induced by the addition of 4-20 nM dexamethasone in the presence of 500 μM ketamine for 16 - 24 hours. Solutions of NR2B antagonists were prepared in DMSO and serially diluted with DMSO to yield 10 solutions differing by 3-fold in - 9 -
concentration. A 96-well drag plate was prepared by diluting the DMSO solution 250-fold into assay buffer (Hanks Balanced Salt Solution (HBSS) Mg2+ free (Gibco #14175-079) containing 20 mM HEPES, 2 mM CaCl2, 0.1 % BSA and 250 DM Probenecid (Sigma # P-8761)). After induction, the cells were washed twice (Labsystem cell washer, 3 fold dilutions leaving 100 DL) with assay buffer and loaded with 4 DM of the calcium fluorescence indicator fluo-3 AM
(Molecular Probes # P- 1241) in assay buffer containing Pluronic F-127 (Molecular Probes # P- 3000) and 10 DM ketamine at 37 °C for one hour. The cells were then washed eight times with assay buffer leaving 100 μL of buffer in each well. Fluorescence intensity was immediately measured in a FLIPR (Fluorometric Imaging Plate Reader, Molecular Devices) using an excitation of 488 nm and emission at 530 nm. Five seconds after starting the recording of fluorescence intensity, 50 DL of agonist solution (40 DM glutamate /glycine, the final concentration 10 DM) was added and after one minute, when fluorescence signal was stable, 50 DL of NR2B antagonists and control solutions from the drug plate were added and the fluorescence intensity recorded for another 30 minutes. The IC50 values were determined by a non-linear least squares fitting of the endpoint fluorescence values to Equation #1 below.
Equation #1:
(Ymax - Ymin) Endpoint Florescence = + Ymin l + tfDrugj / ICsor
where, Ymin is average endpoint fluorescence of the control wells containing 1 DM of AMD-2 and Ymax is the average endpoint fluorescence of wells containing 0.1% DMSO in assay buffer.
Binding Assay To Determine Ki NR2B Antagonists
The radioligand binding assay was performed at room temperature in 96-well microtiter plates with a final assay volume of 1.0 mL in 20 mM Hepes buffer (pH 7.4) containing 150 mM NaCl. Solutions of NR2B antagonists were prepared in DMSO and serially diluted with DMSO to yield 20 μL of each of 10 solutions differing by 3-fold in concentration. Non-specific binding (NSB) was assessed using AMD-1 (10 μM final concentration), and total binding (TB) was measured by addition of DMSO (2% final concentration). Membranes expressing NRla/NR2B receptors (40 pM final concentration) and tritiated AMD-2 (1 nM final concentration) were added to all wells of the microtiter plate. After 3 hours of incubation at room temperature, - 10 -
samples are filtered through Packard GF/B filters (presoaked in 0.05% PEI, polyethyleninine Sigma P-3143) and washed 10 times with 1 mL of cold 20 mM Hepes buffer per wash. After vacuum drying of the filter plates, 40 μL of Packard Microscint-20 was added and bound radioactivity determined in a Packard TopCount. The apparent dissociation constant (Kτ), the maximum percentage inhibition (%Imax)> the minimum percentage inhibition (%Imin) and the hill slope (nH) were determined by a non-linear least squares fitting the bound radioactivity (CPM bound) to Equation #2 below.
Equation #2:
(SB) (%Imaχ - %Imin) /100
CPM Bound = + NSB + (SB)( 100 - %Imax)/l 00 (1 + ( [DragMK: (1 + [AMD-2]/KD) ) ^ )
where, KD is the apparent dissociation constant for the radioligand for the receptor as determined by a hot saturation experiment and SB is the specifically bound radioactivity determined from the difference of TB and NSB control wells.
Synthesisof AMD-1 and AMD-2 may be accomplished according to the following reaction schemes:
The precursor 26 for the synthesis of radiolabelled AMD-1 can be synthesized in accordance with the following procedure:
11
Reaction A
In accordance with the procedures of Reaction A, hydrogen chloride is bubbled through a solution of cinnamonitrile 24 in methanol at room temperature. The volatiles are removed under reduced pressure and the resulting residue is triturated with ether and filtered to yield the intermediate imidate 25. Imidate 25 is dissolved in methanol at ambient temperature, treated with amine 27 (commercially available from Acros Chemicals) at ambient temperature and stirred under argon. The volatiles are removed under reduced pressure and the residue purified by preparative HPLC or trituration with ether to afford amidine 26. Titrated AMD-2 can be synthesized according to the following procedure:
Reaction B
Tritiated AMD-2 was prepared by the following procedure, illustrated above in Reaction B: The precursor 26 (2mg, 0.008mmol) dissolved in dimethylformamide (0.6mL) and potassium carbonate (1.2mg) for lh. High specific activity tritiated methyl iodide (50mCi, 0.0006mmol, in toluene lmL, commercially available from American Radiolabeled Chemicals) was added at room temperature and stirred for 2 hours. The reaction mixture was filtered using a Whatman PTFE 0.45 μm syringeless filter device to remove any insoluble potassium carbonate, washed with Abs. ethanol (2mL, commercially available from Pharmco), and the combined filtrates were concentrated to dryness at room temperature using a rotary evaporator; this also removed any unreacted tritiated methyl iodide. The residue was purified by HPLC chromatography on a Phenomenx Luna C8 semi-prep column (Luna 5 micro C8(2), 250x10.0
- 12 -
mm) using a gradient system of 20/80 acetonitrile/water with 0.1% trifluoroacetic acid to 100% acetonitrile with 0.1% trifluoroacetic acid in 20min. Total activity of the product was 8mCi. Further purification was effected by absorption onto a Waters C-18 Sep-pak column (Waters Sep-Pak PLUS C18) and elution with water followed by absolute ethanol. The product was diluted with absolute ethanol (lOmL) before submission for final analysis. AMD-1 can be synthesized according to the general procedure described by C. F. Claiborne et al (Bioorganic & Medchem Letters 13, 697-700 (2003). Unlabelled AMD-2 is prepared as follows:
Reaction C
In accordance with Scheme lb, hydrogen chloride is bubbled through a solution of cinnamonitrile 24 in methanol at room temperature. The volatiles are removed under reduced pressure and the resulting residue is triturated with ether and filtered to yield the intermediate imidate 25. Imidate 25 is dissolved in methanol at ambient temperature, treated with amine 29 at ambient temperature and stirred under argon. The volatiles are removed under reduced pressure and the residue purified by preparative HPLC or trituration with ether to afford amidine 28. The compounds of this invention exhibit IC50 and Ki values of less than 50 μM in the functional and binding assays, respectively. It is advantageous that the IC50 and Kτ values be less than 5 μM in the functional and binding assays, respectively. It is more advantageous that the IC50 and KΪ values be less than 1 μM in the functional and binding assays, respectively. It is still more advantageous that the IC50 and Ki values be less than 0.1 μM in the functional and binding assays, respectively. The present compounds are NMDA NR2B receptor antagonists, and as such are useful for the treatment and prophylaxis of diseases and disorders mediated through the NR2B receptor. Such diseases and disorders include, but are not limited to, Parkinson's disease, neuropathic pain (such as postherpetic neuralgia, nerve injury, the "dynias", e.g., vulvodynia, phantom limb pain, root avulsions, painful diabetic neuropathy, painful traumatic mononeuropathy, painful polyneuropathy), central pain syndromes (potentially caused by
- 13 -
virtually any lesion at any level of the nervous system), and postsurgical pain syndromes (eg, postmastectomy syndrome, postthoracotomy syndrome, stump pain)), bone and joint pain (osteoarthritis), repetitive motion pain, dental pain, cancer pain, myofascial pain (muscular injury, fibromyalgia), perioperative pain (general surgery, gynecological), chronic pain, dysmennorhea, as well as pain associated with angina, and inflammatory pain of varied origins (e.g. osteoarthritis, rheumatoid arthritis, rheumatic disease, teno-synovitis and gout), headache, migraine and cluster headache, depression, anxiety, schizophrenia, stroke, traumatic brain injury, Alzheimer's disease, cerebral ischemia, amyotrophic lateral sclerosis, Huntington's disease, sensorineural hearing loss, tinnitus, glaucoma, neurological damage caused by epileptic seizures or by neurotoxin poisoning or by impairment of glucose and/or oxygen to the brain, vision loss caused by neurodegeneration of the visual pathway, Restless Leg Syndrome, multi-system atrophy, non-vascular headache, primary hyperalgesia, secondary hyperalgesia, primary allodynia, secondary allodynia, or other pain caused by central sensitization. Compounds of formula I may be used to prevent dyskinesias, particularly the side effects accompanying normal doses of L- Dopa. Furthermore, compounds of formula I may be used to decrease tolerance and/or dependence to opioid treatment of pain, and for treatment of withdrawal syndrome of e.g., alcohol, opioids, and cocaine. The compounds of this invention are also useful for treating or preventing HIV- and HIV treatment-induced neuropathy, chronic pelvic pain, neuroma pain, complex regional pain syndrome, chronic arthritic pain and related neuralgias, treating or preventing chronic lower back pain, and treating or preventing pain resulting from, or associated with, traumatic nerve injury, nerve compression or entrapment, postherpetic neuralgia, trigeminal neuralgia, diabetic neuropathy, cancer and chemotherapy. It is understood that compounds of this invention can be administered at prophylactically effective dosage levels to prevent the above-recited conditions, as well as to prevent other conditions mediated through the NMDA NR2B receptor. Compounds of Formula la may be used in combination with other drugs that are used in the treatment/prevention/suppression or amelioration of the diseases or conditions for which compounds of Formula la are useful. Such other drugs may be administered, by a route and in an amount commonly used therefor, contemporaneously or sequentially with a compound of Formula la. When a compound of Formula la is used contemporaneously with one or more other drugs, a pharmaceutical composition containing such other drugs in addition to the compound of Formula la is preferred. Accordingly, the pharmaceutical compositions of the present invention include those that also contain one or more other active ingredients, in addition - 14 -
to a compound of Formula la. Examples of other active ingredients that may be combined with a compound of Formula la, either administered separately or in the same pharmaceutical compositions, include, but are not limited to: (1) non-steroidal anti-inflammatory agents; (2) COX-2 inhibitors; (3) bradykinin Bl receptor antagonists; (4) sodium channel blockers and antagonists; (5) nitric oxide synthase (NOS) inhibitors; (6) glycine site antagonists; (7) potassium channel openers; (8) AMPA/kainate receptor antagonists; (9) calcium channel antagonists; (10) GABA-A receptor modulators (e.g., a GABA- A receptor agonist); (11) matrix metalloprotease (MMP) inhibitors; (12) thrombolytic agents; (13) opioids such as morphine; (14) neutrophil inhibitory factor (NIF); (15) L-Dopa; (16) carbidopa; (17) levodopa/carbidopa; (18) dopamine agonists such as bromocriptine, pergolide, pramipexole, ropinirole; (19) anticholinergics; (20) amantadine; (21) carbidopa; (22) catechol O-methyltransferase ("COMT") inhibitors such as entacapone and tolcapone; (23) Monoamine oxidase B ("MAO-B") inhibitors; (24) opiate agonists or antagonists; (25) 5HT receptor agonists or antagonists; (26) NMDA receptor agonists or antagonists; (27) NK1 antagonists; (28) selective serotonin reuptake inhibitors ("SSRI") and/or selective serotonin and norepinephrine reuptake inhibitors ("SSNRI"); (29) tricyclic antidepressant drugs, (30) norepinephrine modulators; (31) lithium; (32) valproate; and (33) neurontin (gabapentin). Creams, ointments, jellies, solutions, or suspensions containing the instant compounds can be employed for topical use. Mouth washes and gargles are included within the scope of topical use for the purposes of this invention. A formulation intended for the oral administration to humans may conveniently contain from about 0.5mg to about 5g of active agent, compounded with an appropriate and convenient amount of carrier material which may vary from about 5 to about 95 percent of the total composition. Unit dosage forms can generally contain between from about lmg to about 1 OOOmg of the active ingredient. The conditions recited herein can be treated or prevented by the administration of from about 0.0 lmg to about 140mg of the instant compounds per kilogram of body weight per day. It is understood, however, that the specific dose level for any particular patient will depend upon a variety of factors. Such factors include the age, body weight, general health, sex, and diet of the patient. Other factors include the time and route of administration, rate of excretion, drug combination, and the type and severity of the particular disease undergoing therapy. For example, inflammatory pain may be effectively treated by the administration of from about O.Olmg to about 75mg of the present compound per kilogram of body weight per day, or alternatively about 0.5mg to about 3.5g per patient per day. Neuropathic pain may be - 15 -
effectively treated by the administration of from about O.Olmg to about 125mg of the present compound per kilogram of body weight per day, or alternatively about 0.5mg to about 5.5g per patient per day. The abbreviations used herein are as follows unless specified otherwise:
4-MeBnOH 4-Methylbenzyl alcohol
GDI 1 , 1 ' -Carbonyldiimidazole
TEA Triethylamine
TBSC1 t-Butyldimethylsilyl chloride
DMF Dimethylformamide
(+)-BINAP (+)-2,2'-Bis(diphenylphosphino)-l,l '-binaphthyl
NaOtBu Sodium t-butoxide
DIPEA Diisopropylethylamine
EtOAc Ethyl acetate
TBSOTf t-Butyldimethylsilyl triflate
TBS t-butyldimethylsilyl
THF Tetrahydrofuran
DMAP 4-Dimethylaminopyridine
RT Room temperature h Hours min Minutes
DCM Dichloromethane
MeCN Acetonitrile iPrOH 2-Propanol n-BuOH 1-Butanol
EDC l-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride
HO At l-Hydroxy-7-azabenzotriazole
The compounds of the present invention can be prepared readily according to the following Schemes and specific examples, or modifications thereof, using readily available starting materials, reagents and conventional synthesis procedures. In these reactions, it is also possible to make use of variants which are themselves known to those of ordinary skill in this art but are not mentioned in greater detail. The general procedures for making the compounds claimed in this invention can be readily understood and appreciated by one skilled in the art from viewing the following Schemes. - 16 -
Scheme 1
H2, catalyst
isopropyl group such as tetrahydropyranyl
The synthesis of certain aryl-alkoxy substituted cycloalkanes is depicted in Scheme 1. In the first step, a hydroxy-cycloalkyl-amine 1 is protected with a suitable nitrogen protecting group stable to acidic conditions, such as benzyloxycarbonyl or phthalimidyl. The protected hydroxy-cycloalkyl-amine 2 is converted into a trialkylsilyl ether such as tert-
17
butyldimethylsilyloxy, triethylsilyloxy-, triisopropylsilyloxy or trimethylsilyloxy-ether 3 using the standard literature procedures such as the one described in the literature (E. J. Corey and A. Venkateswarlu, J. Am. Chem. Soc. 1972. 94, 6190-91. The trialkylsilyloxy-ether 3 is then reductively alkylated with an aldehyde or ketone in the presence of a trialkylsilane such as triethylsilane or tert-butyldimethylsilane and a suitable aprotic acid catalyst such as trimethylsilyl triflate (S. Hatakeyama, H. Mori, K. Kitano, H. Yamada, and M. Nishizawa, Tetrahedron Lett., 1994. 35, 4367-70.), trimethylsilyl bromide or iodide (M. B. Sassaman, K. D. Kotian, G.K. Surya Prakash, and G. A. Olah, J. Org. Chem., 1987. 52, 4314-19) yielding an arylalkyl ether 4. A convenient procedure for generating the trialkylsilyl bromide catalyst in situ, is through the addition of catalytic amounts of bismuth tribromide in acetonitrile solvent (N. Komatsu, J. Ishida, H. Suzuki, Tetrahedron Lett., 1997. 38, 7219-22; J. S. Bojwa, X. Jiang, J. Slade, K. Prasad, O. Repic, T. J. Blacklock, Tetrahedron Lett. 2002, 43, 6709-13). The nitrogen protecting group is removed in the next step using standard methods such as hydrogenolysis, hydrazinolysis or acid hydrolysis, generating the amine-ether 5. The amine is alkylated with 4-chloro-lH- pyrazolo[3,4-d]pyrimidine 6 (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790 (1956)) using standard alkylation conditions providing the 4-amino-lH-pyrazolo[3,4-d]pyrimidines 7. As an alternative, a suitably N-alkoxymethyl protected derivative of 6 such as N-tetrahydropyranyl, N- tetrahydrofuranyl , or N-ethoxyethylidene provides cleaner products and avoids polymeric products arising from further alkylation of the lH-pyrazolo[3,4-d]pyrimidine N-l nitrogen. This type of protecting group is easily removed by brief treatment with aqueous acid in the last step.
18
Scheme 2
P1 = protecting group such as benzyloxycarbonyl or alkyl-urethane R1- g-X
Z' = absent or Cι_e alkyl unsubstituted or substituted where X = halogen with one or more substituents selected from:
H deprotection
19
The synthesis of certain aryl-hydoxy-alkyl substituted cycloalkanes is depicted in Scheme 2. In the first step, a carboxy-cycloalkyl-amine is protected with a suitable nitrogen protecting group stable to organomagnesium or organolithium reagents, such as benzyloxycarbonyl or tert-butyloxycarbonyl urethanes. The protected carboxy-cycloalkyl-amine 8 is converted into an N-methoxy-N-methyl amide 9 using the standard literature procedures. The N-methoxy-N-methyl amide is converted into an arylalkyl ketone 10 using an organometallic reagent as described in the literature (S. Nahm and S. M. Weinreb, Tetrahedron Lett., 1981. 22, 3815-3818). The ketone 10 is reduced to alcohol 11 with a hydride reagent such as sodium borohydride or hydrogenated with a catalyst An alternative procedure is to convert either the N-methoxy-N-methyl amide 9 or the carboxylic acid 8 into an aldehyde derivative 14 which undergoes addition of the organometallic reagent to form the alcohol 11. The nitrogen protecting group is removed in the next step using standard methods such as hydrogenolysis, hydrazinolysis or acid hydrolysis, generating the amine-alcohol 12. The amine 12 is alkylated with 4-chloro-lH-pyrazolo[3,4-d]pyrimidine 6 (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790 (1956)) using standard alkylation conditions providing the 4-amino- 1 H-pyrazolo[3 ,4- djpyrimidines 7. As an alternative, a suitably N-alkoxymethyl protected derivative of 6 such as N-tetrahydropyranyl, N-tetrahydrofuranyl , or N-ethoxyethylidene provides cleaner products and avoids polymeric products arising from further alkylation of the lH-pyrazolo[3,4-d]pyrimidine N-l nitrogen. This type of protecting group is easily removed by brief treatment with aqueous acid in the last step.
20
Scheme 3
The synthesis of certain aryl-alkyl substituted cycloalkanes is depicted in Scheme 3. In the first step, a aldehyde-cycloalkyl-amine 14, protected with a suitable nitrogen protecting group stable to organomagnesium or organolithium reagents, such as benzyloxycarbonyl or tert-butyloxycarbonyl urethanes, is reacted with a phosphorane reagent 21
(Wittig reagent) using the standard literature procedures. The resulting olefin-urethane 10 is deprotected using standard methods such as, acid hydrolysis, generating the amine-olefin 16. The amine 16 is alkylated with 4-chloro-lH-pyrazolo[3,4-d]pyrimidine 6 (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790 (1956)) using standard alkylation conditions providing the 4-amino-lH- pyrazolo[3,4-d]pyrimidines 17. As an alternative, a suitably N-alkoxymethyl protected derivative of 6 such as N-tetrahydropyranyl, N-tetrahydrofuranyl , or N-ethoxyethylidene provides cleaner products and avoids polymeric products arising from further alkylation of the lH-pyrazolo[3,4- djpyrimidine N-l nitrogen. This type of protecting group is easily removed by brief treatment with aqueous acid in the last step. The olefin 17 is reduced to alkyl-cycloalkyl-4- amino-lH- pyrazolo[3,4-d]pyrimidine 18 hydrogenation over a catalyst .
22 -
Scheme 4
23
A preferred embodiment is the incorporation of a fluorine substituent into the alkyl-, hydroxy-alkyl or alkoxyl side chain or cyclohexane ring. This can be effected by reaction of a hydroxy intermediate such as 11 , 21 or 22 with diethylaminosulfur trifluoride [DAST] similar reagent as illustrated in Scheme 4. The incorporation of geminal a difluoro substitutent can be effected through the use of diethyl sulfur trifluoride on a ketone intermediate such as 20. The ketone and hydroxy intermediates 20 and 21 can be obtained as shown in Scheme 4 by the ether synthesis described for Scheme 1 substituting an unsaturated aldehyde or ketone in the alkylation step. Cleavage of the olefin intermediate 19 yields the ketone 20 which can be further reduced to give hydroxy intermediate 21 with a hydride reducing agent such as sodium borohydride. Reaction of the hydroxy intermediate 21 with diethyl sulfur trifluoride generates the fluoro compound 22. Conversion of 21 into the 4-amino-lH-pyrazolo[3,4-d]pyrimidine 23 uses the methodology as described in Schemes 1-3 above. The use of a chiral reducing agent further provides a a majority of the desired enantiomer of 21. This enantiomerically enhanced form of 21 yields a majority of the desired enantiomer of the chiral fluoro compound 23.
Example 1 trans-(4-Phenethyloxy-cvclohexyl)-(lH-pyrazoIof3,4-d1pyrimidin-4-yl)-amine
Step 1: frans-2-(4-Hvdroxy-cvclohexyl)-isoindole-1.3-dione
Step 2: trans-2-f4-ftert-Butyl-dimethyl-silyloxy-cvclohexyl -isoindole-1.3-dione
Step 3 : trans-2-('4-Phenylethyloxy-cvclohexyl')-isoindole- 1 ,3-dione
Concentration under reduced pressure gave 7.1 g of phenyl acetaldehyde as a volatile liquid. IH NMR (400 MHz, CDC13) 9.8 (s, IH), 7.5-7.2 (m, 5H), 3.7 (s 2H). To a stirred mixture of 10 g
- 25 -
of trans-2-(4-(tert-butyl-dimethyl-silyloxy-cyclohexyl)-isoindole-l,3-dione (Compound 2), 150 mL of anhydrous acetonitrile, 7 mL of triethylsilane and 0.7 g of bismuth tribromide was added 5 g of the freshly prepared phenyl acetaldehyde slowly keeping the temperature at or below 25°C by means of a cooling bath. After stirring for 2 h, the reaction was quenched with 50 mL of saturated sodium bicarbonate and extracted with 3 x 150 mL portions of ethyl acetate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 2%-25% ethyl acetate in hexane gave 9.0 g of product as a white crystalline solid: IH NMR (400 MHz, CDC13) 7.8 (m, 2H), 7.7 (m, 2H), 7.3-7.1 (m, 5H), 4.15 (m, IH), 3.7 (t, 2H), 3.38 (m, IH), 2.9 (t, 2H), 2.22 (d, 2H), 2.3 (dd, 2H), 2.18 (d, 2H), 1.78 (d, 2H), 1.4 (dd, 2H).
Step 4: trans 4-Phenylethyloxy-cvclohexylamine
To a solution of 9 g of trans-2-(4-phenylethyloxy-cyclohexyl)-isoindole-l,3-dione in 60 mL of THF and 150 mL of ethanol was added 3.75 mL of hydrazine hydrate and the mixture heated to reflux for 4 h, then 80 mL of 6N HCI was added and the reflux was continued for lh. The cooled mixture was concentrated under reduced pressure to remove ethanol and filtered. The filter pad was washed with 2 x 50 mL of dilute HCI and the combined filtrates basified to pH 10 with 20% sodium hydroxide and extracted with 3 x 150 mL portions of chloroform. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Further drying under vacuum gave 6 g of product as an oil. MS (m+1) = 220.2; IH NMR (400 MHz, CDC13) 7.3-7.1 (m, 5H), 3.7 (t 2H), 3.2 (m, IH), 2.9 (t, 2H), 2.7 (m, IH), 2.0 (d, 2H), 1.85 (d, 2H), 1.4 (br s, 2H), 1.3 (dd, 2H), 1.15 (dd, 2H).
Step 5 : trans-f 4-Phenethyloxy-cvclohexylH 1 H-pyrazolo \3.4-d]pyrimidin-4-yl -amine
26
A mixture of 219 mg of trans-4-(2-phenyl-ethoxy)-cyclohexylamine, 154 rag of 4- chloro-lH-pyrazolo[3,4-d]pyrimidine (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790 (1956)), 10 mL of 2-propanol and 0.174 mL of N,N-diisopropyl-ethylamine was heated to 80°C for 12 hours. The mixture was cooled and concentrated under reduced pressure and purified by either preparative TLC eluting with 50:50:5 THF: diethyl ether: NH40H or preparative reverse phase chromatography on delta Pak C (C-18 column) eluting with a gradient of 90:10 to 0:100 of 0.1% TFA in H20: CH3CN gave 60-92% of (4-phenethyloxy-cyclohexyl)-(lH-pyrazolo[3,4- d]ρyrimidin-4-yl)-amine as a white crystalline solid. MS (m+1) = 338.32; IH NMR (400 MHz, CDC13) 8.43 (s, IH), 7.92 (s, IH), 7.3-7.2 (m, 5H), 3.7 (t, 2H), 3.3 (m, IH), 2.9 (t, 2H), 2.22 (d, 2H), 2.1 (d, 2H), 1.7 (m, IH), 1.5 (dd, 2H), 1.4 (m, 2H). Example 2 trans-14-(2-Fluoro-2-phenyl-ethoxy-cyclohexyl -(lH-pyrazolo[3<4-dlpyrtmidin-4-yl -amine
Step 1 : trans-2-r4-("S-Methyl-2-phenyl-hex-2-enyloxy)-cyclohexyll-isoindole- 1 ,3-dione
27
To a stirred mixture of 1 g of trans-2-(4-(tert-butyl-dimethyl-silyloxy-cyclohexyl)- isoindole-l,3-dione, 20 mL of anhydrous acetonitrile, 0.8 mL of triethylsilane and 0.6 g of 5- methyl-2-phenyl-2-hexenal (commercial, predominantly trans was added ) 0.08 g of bismuth tribromide. After stirring for 1.3 h, the reaction was quenched with 10 mL of saturated sodium bicarbonate and extracted with 3 x 25 mL portions of ethyl acetate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of l%-20% ethyl acetate in hexane gave first 0.30 g of saturated product, trans-2-[4-(5-methyl-2-phenyl-hexyloxy)-cyclohexyl]-isoindole- 1 ,3-dione, then 0.50 g of product as a resin: IH NMR (400 MHz, CDC13) 7.8 (m, 2H), 7.7 (m, 2H), 7.3-7.1 (m, 5H), 5.8 (t, IH), 4.25 (s, 2H), 4.15 (m, 2H), 3.4 (m, IH), 2.3 (m, 2H), 2.1 (d, 2H), 1.9 (t, 2H), 1.75 (d, 2H), 1.65 (m, IH), 1.35 (m, 2H), 1.3 (t, 2H), 0.9 (d, 6H). Step 2 : trans-2- r4-("2-Oxo-2-phenyl-ethoxy -cyclohexyll -isoindole- 1.3 -dione
To a stirred solution of 2 g of trans-2-[4-(5-methyl-2-phenyl-hex-2-enyloxy)- cyclohexyl]-isoindole- 1,3 -dione in 100 mL of dichloromethane cooled to -78°C was dispersed a stream of ozone from an ozone generator until a blue color persisted. The excess ozone was purged with nitrogen until the blue color dissipated, and 5 mL of methyl sulfide was added. After warming to room temperature over 30 min, the solution was concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 2%-30% ethyl acetate in hexane gave 1.8 g of product as a white crystalline solid: IH NMR (400 MHz, CDC13) 8.0 (d,
28
2H), 7.8 (m, 2H), 7.6 (t, IH), 7.5 ( t, 2H), 4.8 (s, 2H), 4.18 (m, IH), 3.5 (m, IH), 2.35 and 2.25 (overlapping dd and d, 4H), 1.8 (d, 2H), 1.5 (dd, 2H).
Step 3 : trans-2-r4-(2-Hvdroxy-2-phenyl-ethoxy)-cvclohexyl1-isoindole- 1 ,3-dione
A mixture of 1 g of trans-2-[4-(2-oxo-2-phenyl-ethoxy)-cyclohexyl]-isoindole-l,3-dione and 0.1 g of 10% palladium on carbon in 100 mL of ethanol was stirred under 1 arm. of hydrogen overnight. The catalyst was filtered off and the filtrate concentrated to dryness under reduced pressure. Drying under vacuum gave 1.0 g of product as a white crystalline solid: IH NMR (400 MHz, CDC13) 7.8 (m, 2H), 7.65 (t, IH), 7.4-7.2 ( m, 5H), 4.82 (d, IH), 4.1 (m, IH), 3.65 (m, 2H), 3.4 (m, 2H), 2.3 (dd, 2H), 2.2 (m, 2H), 1.8 (d, 2H), 1.4 (dd, 2H).
Step 4: trans-2-r4-("2-Fluoro-2-phenyl-ethoxy)-cvclohexyll-isoindole- 1 ,3-dione
To a stirred solution of 1 g of trans-2-[4-(2-hydroxy-2-phenyl-ethoxy)-cyclohexyl]- isoindole- 1,3 -dione in 100 mL of dichloromethane cooled to -78°C under nitrogen atmosphere was added 1.2 g of diethyl-amino sulfur-trifluoride. The mixture was allowed to warm and stir for 24 h, then quenched with 25 mL of saturated sodium carbonate. After stirring for 15 min, the mixture was diluted with 25 mL of dichloromethane and the layers separated. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The catalyst was filtered off and the filtrate concentrated to dryness under reduced pressure. Chromatography over silica gel eluting with a gradient of 2%-30% ethyl acetate in hexane gave 0.7 g of product as a white crystalline solid: IH NMR (400 MHz, CDC13) 7.8 (m, 2H), 7.7 (t, IH), 7.4-7.3 ( m, - 29 -
5H), 5.6 ( dd, IH), 4.1 (m, IH), 3.9-3.65 (complex m, 2H), 3.45 (m, IH), 2.3 (dd, 2H), 2.2 (m, 2H), 1.8 (d, 2H), 1.4 (dd, 2H).
Step 5: trans-4-(,2-Fluoro-2-phenyl-ethoxy)-cyclohexyl-amine
To a solution of 0.7 g of racemic trans-2-[4-(2-fluoro-2-phenyl-ethoxy)-cyclohexyl]- isoindole- 1,3 -dione in 15 mL of THF and 15 mL of ethanol was added 0.3 mL of hydrazine hydrate and the mixture heated to reflux for 4 h, then 5 mL of 6N HCI was added and the reflux was continued for lh. The cooled mixture was concentrated under reduced pressure to remove ethanol and filtered. The filter pad was washed with 2 x 10 mL of dilute HCI and the combined filtrates basified to pH 10 with 20% sodium hydroxide and extracted with 3 x 25 mL portions of chloroform. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Further drying under vacuum gave 0.4 g of product as an oil. MS (m+1) = 238.3.
Step 6: 4-Chloro-l-(tetrahvdro-pyran-2-yl -lH-pyrazolor3,4-d1pyrimidine and 4-chloro-2- ("tetrahvdro-pyran-2-yl)-2H-pyrazolor3,4-d1pyrimidine
A mixture of 8.5 g of 4-chloro-pyrazolo[3,4-d]pyrimidine, 600 mL of ethyl acetate, and 400 mg of camphor-sulfonic acid was stirred overnight. The mixture was washed with 25 mL of saturated sodium carbonate, dried over magnesium sulfate and concentrated to dryness under reduced pressure. Chromatography over silica gel eluting with a gradient of l%-20% ethyl acetate in hexane gave 12 g of the 1- THP product as a white crystalline solid which was stored under nitrogen in the freezer: IH NMR (400 MHz, CDC13) 8.8 (s, IH), 8.2 (s, IH), 6.05 (d, IH). Later fractions eluting with ethyl acetate contained 1.5 g the isomeric 2-THP product: IH NMR (400 MHz, CDC13) 8.25 (s, IH), 8.15 (s, IH), 5.85 (m, IH). The ratio of the two isomeric - 30 -
products varied, but either isomer could be used in the alkylation step to generate a 4- alkylamino-pyrazolo[3,4-d]pyrimidine.
Step 7 : frans-[4-(2-Fluoro-2-ρhenyl-ethoxy-cvclohexyl)-( 1 H-pyrazolo \3 ,4-dlpyrimidin-4-yl)- amine
A mixture of 0.4 g of trans-4-(2-fluoro-2-phenyl-ethoy)-cyclohexyl- amine, 0.5 g of 4- chloro-l-(tetrahydro-pyran-2-yl)-lH-pyrazolo[3,4-d]pyrimidine, and 0.4 mL of N,N- diisopropylethylamine in 25 mL of 2-propanol was heated to reflux under nitrogen overnight. The mixture was cooled and concentrated under reduced pressure. The tan residue was taken up in 200 mL of ethyl acetate, washed with 20 mL of saturated sodium bicarbonate, dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 50%- 100% ethyl acetate in hexane gave 0.72 g of product as a white solid. The solis was taken up in 75 mL of methanol and 5 mL of 6N HCI and heated at reflux for 15 minutes, cooled and concentrated under reduced pressure to dryness. The solid residue was treated with 10 mL of concentrated aqueous ammonia and again concentrated to dryness. The resulting residue was extracted with 100 mL of chloroform, filtered and concentrated to dryness under reduced pressure. Chromatography over silica gel eluting with a gradient of l%-5% methanol in ethyl acetate gave 0.45 g of product as a white solid: MS (m+1) = 356.3; IH NMR (400 MHz, CDC13) 8.4 (s, IH), 7.9 (s, IH), 7.4-7.3 (m, 5H), 5.6 (dd, IH), 3.9-3.65 (complex m, 3H), 3.4 (m, IH), 2.3 (m, 2H), 2.2 (m, 2H), 1.75-1.4 (m, 4H).
Resolution into the pure enantiomers could be performed by isocratic elution on ChiralPak AD at 1 mL /min, eluting with 20% methanol in 2-propanol.
Example 3 trans [4-(2,2-Difluoro-2-phenyl-ethoxy)-cvcIohexyl)-carbamic acid tert-butyl ester
- 31
Step 1 : trans (4-Hydroxy-cyclohexyD-carbamic acid tert-butyl ester
A mixture of 5 g of trans 4-aminocyclohexanol and 9.5 g of di-tert-butyl di-carbonate in 200 mL of THF was heated to reflux for 2 h at which time the mixture became homogeneous. The mixture was cooled and concentrated under reduced pressure. Drying under vacuum gave 9.34 g of product as a white crystalline solid; IH NMR (400 MHz, CDC13) 4.4 (br s, 2H), 3.6 (m, IH), 3.4 (br s, IH), 2.0 (t, 4H), 1.45 (s, 9H), 1.4 (dd, 2H), 1.2 (dd, 2H).
Step 2: cis (4-Hvdroxy-cvclohexyl)-carbamic acid tert-butyl ester
To a stirred mixture of 2.2 g of trans (4-hydroxy-cyclohexyl)-carbamic acid tert-butyl ester, 4 g of triphenyl-phosphine, 4.2 g of 4-nitrobenzoic acid, 120 mL of benzene and 10 mL of THF was added 3.5 g of diisopropyl-azo-di-carboxylate over 5 min. The mixture was allowed to stir at room temperature for 4 h and then concentrated under reduced pressure , taken up in 250 mL of dichloromethane and filtered and again concentrated. Chromatography on silica gel eluting with a gradient of 2%-20% ethyl acetate in hexane gave 1.2 g of product as a crystalline solid; IH NMR (400 MHz, CDC13) 8.3 (d, 2H), 8.2 (d, 2H), 3.8 (br m, IH), 3.6 (br m, IH), 2.4 (d, IH), 2.1-1.6 (complex m, 8H), 1.45 (s, 9H).
- 32 -
Step 3: cis (4-Hvdroxy-cvclohexyl)-carbamic acid tert-butyl ester
A mixture of 1.2 g of cis (4-hydroxy-cyclohexyl)-carbamic acid tert-butyl ester, 20 mL of 2N sodium hydroxide and 50 mL of THF was heated to reflux for 12 h. The mixture was cooled, diluted with 50 mL of water and extracted with 3 x 50 mL portions of ether. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Drying under vacuum gave 0.70 g of product as a white crystalline solid; IH NMR (400 MHz, CDC13) 4.5 (m, IH), 3.9 (m, IH), 3.5 (br s, IH), 1.6 (m, 8H), 1.42 (s, 9H).
Step 4: 2.2-Difluoro-2-phenyl-ethanol
A stirred mixture of 2.2 g of difluoro-2-phenyl acetic acid ethyl ester (W.J. Middleton, E.M. Bingham, J. Org. Chem., 45, 2883-2887 (1980)), and 0.6 g of sodium borohydride in 75 mL of ethanol was kept at room temperature overnight, concentrated to near dryness under reduced pressure carefully acidified with 20 mL of 5% HCI and extracted into 3 x 50 mL of dichloromethane. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Drying under vacuum gave 1.7 g of product as an oil: IH NMR (400 MHz, CDC13) 7.5 (m, 5H), 4.0 (t, 2H).
Step 5: trans r4-(2,2-Difluoro-2-phenyl-ethoxy)-cvclohexylVcarbamic acid tert-butyl ester
- 33
To a stirred mixture of 0.23 g of g of cis-(4-hydroxy-cyclohexyl)-carbamic acid tert- butyl ester,0.54 g of 1.1 '-(azodicarbonyl)-dipiperidine and 20 mL of benzene was added 0.4 g of tri-n-butyl-phosphine and 1.3 g (8 equivalents) of 2,2-difluoro-2-phenyl-ethanol. The mixture was heated to 60°C overnight, then an additional 0.5 g of 1.1 '-(azodicarbonyl)-dipiperidine and 0.4 g of tri-n-butyl-phosphine was added and heating continued for another 24 h. The mixture was cooled, diluted with 25 mL of toluene, filtered and the filter pad washed with 5 mL of toluene. The filtrate was purified by chromatography on silica gel eluting with a gradient of 0%- 20% ethyl acetate in hexane gave 0.15 g of product as a resin: IH NMR (400 MHz, CDC13) 7.5 (m, 5H), 3.95 (m, 2H), 3.4 (m, IH), 1.95 (m, 2H), 1.6 (m, 6H), 1.45 (s, 9H).
Step 6: trans 4-(,2,2-Difluoro-2-phenyl-ethoxy)-cyclohexyl)-carbamic acid tert-butyl ester
Example 4
34
trans-{4- [2-(2-Fluoro-phenyl -ethoxyl -cyclohexy -dH-Pyrazolo \3A-d\ pyrimidin-4-yl)- amine
Example 5 trans-{4-f2-f4-Fluoro-phenyl)-ethoxyl-cvcIohexyI}-(lH-pyrazolof3,4-</lpyrimidin-4-yl)- amine
Example 6
35 -
trans-{4-r2-(4-Methyl-phenyl)-ethoxyl-cvclohexy -(lH-PyrazoIor3,4-</lpyrimidin-4-vI)- amine
CDC13) 8.42 (s, IH), 7.92 (s, IH), 7.1 (dd, 4H), 4.0 (m, IH), 3.68 (m, 2H), 3.3 (m, IH), 2.85 (m, 2H), 2.35 (s, 3H), 2.22 (d, 2H), 2.15 (d, 2H), 2.0 (m, IH), 1.4 (m, 4H).
Example 7 trans-{4-f2-(3-Fluoro-phenyl)-ethoxyl-cvclohexyl}-(lH-pyrazolol3,4-</lpyrimidin-4-yl)- amine
Example 8
36
trans-{4-f2-(2-MethvI-phenyl)-ethoxyl-cvclohexyI>-flH-pyrazolo[3,4-</lpyrimidin-4-yl)- amine
CDC13) 8.42 (s, IH), 7.92 (s, IH), 7.15 (m, 4H), 4.0 (m, IH), 3.68 (m, 2H), 3.3 (m, IH), 2.85 (m, 2H), 2.34 (s, 3H), 2.22 (d, 2H), 2.15 (d, 2H), 1.7 (m, IH), 1.5 (m, 2H), 1.4 (m, 2H)..
Example 9 trans-{4-r2-(3-MethvI-phenyl)-ethoxyl-cvclohexyll-(lH-pyrazolo[3,4-<f]pyrimidin-4-vI)- a ine
From 3-methyl-phenylacetic acid ethyl ester, using the procedure described for the preparation of Example 1, Step 3 gave trans-{4-[2-(3-methyl-phenyl)-ethoxy]-cyclohexyl}-(lH- pyrazolo[3,4-φyrimidin-4-yl)-amine as a white solid: MS (m+1) = 352.4; 1Η NMR (400 MHz, CDC13) 8.42 (s, IH), 7.92 (s, IH), 7.2 (m, IH), 7.0 (m, 3H), 4.0 (m, IH), 3.68 (m, 2H), 3.3 (m, IH), 2.85 (m, 2H), 2.33 (s, 3H), 2.22 (d, 2H), 2.15 (d, 2H), 1.7 (m, IH), 1.5 (m, 2H), 1.4 (m, 2H).\
Example 10
- 37
trans-[4-(2-FIuoro-2-(2-fluorophenyl)-ethoxy-cvclohexyl)-flH-pyrazolof3.4dlpyrimidin-4- yl)-amine
Step 1 : trans (4-Hydroxy-cyclohexyl)-carbamic acid benzyl ester
Step 2: trans ("4-tert-Butyl-dimethyl-silanyloxy-cvclohexyl)-carbamic acid benzylester
38 -
A mixture of 30.5 g of trans-(4-hydroxy-cyclohexyl)-carbamic acid benzylester, 23 g of tert-butyldimethylsilyl chloride, 64 g of imidazole and 55 mL of DMF was stirred for 24 h. The mixture was diluted with 250 mL of ether and washed with 4 x 250 mL portions of water, dried over magnesium sulfate and concentrated under reduced pressure. The product slowly crystallized under vacuum as a low melting solid: 45 g; IH NMR (400 MHz, CDC13) 7.4-7.3 (m, 5H), 5.1 (s, 2H), 4.6 (s, IH), 3.6 (m, IH), 3.5 (m, IH), 2.0 (d, 2H), 1.8 (d, 2H), 1.6 (d, IH), 1.4 (dd, 2H), 1.2 (dd, 2H), 0.9 (s, 9H), 1.05 (s, 6H).
Step 3: teans-[4-(2-Bromo-3-phenyl-allyloxy)-cvclohexyl1-carbamic acid benzyl ester
To a stirred mixture of 7.3 g of trans (4-tert-butyl-dimethyl-silanyloxy-cyclohexyl)- carbamic acid benzylester and 5.7 g of 2-bromocinnamaldehyde in 140 mL of anhydrous acetonitrile was added 0.57 g of bismuth tribromide. After 15 min, 5.8 mL of triethyl-silane was added drop-wise over 15 min. After stirring for 1 h, the reaction was complete by TLC analysis and was quenched with 50 mL of saturated sodium bicarbonate, allowed to stir until the black precipitated bismuth metal was consumed with the formation of a white precipitate and extracted with 3 x 250 mL portions of ethyl acetate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 0%-20% ethyl acetate in hexane gave 7.6 g (90%) of product as a white crystalline solid: MS (m+1) = 444.3; IH NMR (400 MHz, CDC13) 7.6 (d, 2H), 7.35 (m, 8H), 7.07 (s IH), 5.08 (s, 2H), 4.6 (s, IH), 4.28 (s, 2H), 3.6 (m, IH), 3.4 (m, IH), 2.06 (d, 4H), 1.48 (dd, 2H), 1.2 (dd, 2H).
Step 4: trans-r4-("2-(2-Fluorophenyl)-3-phenyl-allyloxy)-cyclohexyl1-carbamic acid benzyl ester - 39 -
A stirred mixture of 0.44 g of trans-[4-(2-bromo-3-phenyl-allyloxy)-cyclohexyl]- carbamic acid benzyl ester, 0.15 g of 2-fluorophenylboronic acid, 0.47 g of barium hydroxide octahydrate, 25 mg of tetrakis-triphenylphosphine palladium, 6 mL of DME and 1 mL of water was heated to reflux for 12 h. The mixture was cooled and partitioned between 10 mL of sodium carbonate and 3 x 20 mL of ethyl acetate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 0%-20% ethyl acetate in hexane gave 0.42 g 460.2 of product as a white crystalline solid: MS (m+1) = 460.4; ; IH NMR (400 MHz, CDC13) 7.3-7.2 (m, 9H), 7.1- 6.95 (m, 5H), 6.8 (s IH), 5.05 (s, 2H), 4.55 (s, IH), 4.28 (s, 2H), 3.5 (m, IH), 3.3 (m, IH), 2.0 (m, 4H), 1.4 (dd, 2H), 1.15 (dd, 2H).
Step 5: trans-[4-(2-Fluoro-2-("2-fluorophenyl)-ethoxy-cvclohexyl)-(lH-pyrazolo 3.4-dlpyrimidin- 4-yl)-amine
To a stirred solution of 41 g of trans-[4-(2-(2-fluorophenyl)-3-phenyl-allyloxy)-cyclohexyl]- carbamic acid benzyl ester in 750 mL of dichloromethane and 250 mL of methanol cooled to - 78°C was dispersed a stream of ozone from an ozone generator until a blue color persisted. The excess ozone was purged with nitrogen until the blue color dissipated, and 7.8 g of sodium borohydride was added. After warming to room temperature over 30 min, the solution was diluted with 50 mL of water and concentrated under reduced pressure. The residue was treated with 500 mL of 3N hydrochloric acid and extracted into 3 X 500 mL of ethyl acetate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Chromatography over silica gel eluting with a gradient of 2%-30% ethyl acetate in hexane gave 30 g of product as a white crystalline solid: MS (m+1) = 388.4; IH NMR (400 MHz, CDC13)
- 40 -
7.53 (m, IH), 7.33 (m, 5H), 7.25 (m, IH), 7.14 (m, IH), 7.0 (m, IH), 5.15 (d, IH), 5.07 (s, 2H), 4.6 (m, IH), 3.7 (d, IH), 3.5 (brm, IH), 3.4 (t, IH), 3.3 (m,lH), 2.9 (s, IH), 2.0 (m, 4H), 1.2 (q, 2H), 1.15 (q, 2H).
Step 6: tert-butyl lfra^-4-r2-f2-fluorophenyl)-2-hvdroxyethoxyl-cvclohexyllcarbamate
Step 7: tert-butyl {^ra?i^-4-r2-fluoro-2-('2-fluorophenyl)ethoxy1cvclohexyl}carbamate
Step 9: N-(tr »^-4-r2-fluoro-2-('2-fluorophenyl)ethoxylcvclohexyl)-l- tetrahvdro-2H-pyran-2 vl)- lH-pvrazolo \3.4-ι |pvrimidin-4- amine
Step 10 : trans-r4-('2-Fluoro-2-('2-fluorophenyl)-ethoxy-cvclohexyl)-(lH-pyrazolor3.4- d]pyrimidin-4-yl)-amine
42
A mixture of 0.82 g of N-{trβ«5-4-[2-fluoro-2-(2-fluorophenyl)ethoxy]cyclohexyl}-l- (tetrahydro-2H-pyran-2-yl)-lH-pyrazolo[3,4-c |pyrimidin-4-amine in 75 mL of 2-propanol and 2 mL of 12Ν ΗC1 and heated to 90°C for 1 h, cooled and concentrated under reduced pressure to dryness. The solid residue was triturated with 50 mL of ether and filtered. The solid hydrochloride salt was dissolved in 100 mL of methanol and 2 mL of concentrated aqueous ammonia and again concentrated to dryness. The resulting residue was extracted with 100 mL of chloroform, filtered and concentrated to dryness under reduced pressure. Chromatography over silica gel eluting with a gradient of 5%-10% methanol in ethyl acetate gave 0.67 g of product as a white solid: MS (m+1) = 374.43; 1Η NMR 8.4 (s, 1Η), 7.95 (s, 1Η), 7.48 (m, 1Η), 7.38 (m,
1Η), 7.2 (m, 1Η), 7.05 (m, 1Η), 5.85 (m, JΗF = 47 Hz, IH), 3.8 (m, 3H), 3.42 (br s, IH), 2.25 (d, 2H), 2.18 (d, 2H), 1.58 (q, 2H), 1.4 (br m, 2H).
Resolution into the pure enantiomers could be performed by isocratic elution on ChiralPak AD at 1 mL /min, eluting with 20% methanol in 2-propanol.
- 43
47 Hz, IH), 3.8 (m, 3H), 3.42 (br s, IH), 2.25 (d, 2H), 2.18 (d, 2H), 1.58 (q, 2H), 1.4 (br m, 2H).
Example 11 cis-(4-Phenethyloxy-cvcIohexylmethvI)-(lH-pyrazolof3,4-dlpyrimidip-4-yl)-amine
A mixture of 10 g of ethyl 4-hydroxybenzoate, 5 mL of acetic acid, 0.8 g of 5% rhodium on alumina, and 200 mL of ethanol was shaken under 55 psi of hydrogen for 48 h, filtered and concentrated under reduced pressure. The residue was taken up in 200 mL of toluene and again concentrated under reduced pressure to remove acetic acid. Drying under vacuum overnight gave
11 g of product, which was predominantly cis (83: 17 cis : trans by HPLC), as a colorless oil: MS (m+1) = 173.2; 1HNMR (400 MHz, CDC13) 4.1 (dd, 2H), 3.9 (m, cis isomer, 0.85 H), 3.6 (m, trans isomer, 0.15 H), 2.4 and 2.2 (m, IH), 2.0 (m, 2H), 1.62 (m, 6H), 1.2 (t, 3H).
Step 2: cis-4-tert-Butyl-dimethylsilanyloxy-cvclohexanecarboxylic acid ethyl ester
44
A mixture of 3 g of cis-4-hydroxy-cyclohexanecarboxylic acid ethyl ester, 3 g of imidazole, 33 g of tert-butyldimethylsilyl-chloride, and 6 mL of DMF was stirred under inert atmosphere overnight. The mixture was diluted with 250 mL of water and extracted into 3 x 50 mL portions of ether. The combined ether extracts were washed with 2 x 50 mL of water, dried over magnesium sulfate and concentrated under reduced pressure. Drying under vacuum overnight gave 4.5 g of product as a colorless oil: IH NMR (400 MHz, CDC13) 4.1 (dd, 2H), 3.58 (m, cis isomer, 0.85 H), 2.2 (m, IH), 1.95 (m, 4H), 1.6 (m, IH), 1.5 (m, IH), 1.22 (m, 6H), 0.9 (s, 9H), 0.04 (s, 6H).
Step 3: cis-2-(4-Phenethyloxy)-cyclohexanecarboxylic acid ethyl ester
From 4 g of cis-4-tert-butyl-dimethylsilanyloxy-cyclohexanecarboxylic acid ethyl ester, using the procedure described for Example 1, Step 3 above, gave 3 g of a colorless resin: MS (m+1) = 277.2.
Step 4: cis-(4-Phenethyloxy-cvclohexyl) methanol
To a stirred, ice cold solution of 3 g of cis-2-(4-phenethyloxy)-cyclohexanecarboxylic acid ethyl ester, in 50 mL of THF was added 10 mL of IM lithium aluminum hydride in THF.
The mixture was allowed to warm to room temperature and stir for 1 h, then cooled in an ice bath and quenched with sequential addition of 0.5 mL of water, 0.5 mL of IN sodium hydroxide, and 1.5 mL of water. After stirring for 30 min, the mixture was filtered, washed with 2 x 25 mL of - 45 -
ethyl acetate and combined extracts dried over magnesium sulfate and concentrated under reduced pressure.: MS (m+1) = 235.2, 1H MR (400 MHz, CDC13) 7.2 (m, 5H), 3.6 (t, 2H), 3.35 (m, IH), 3.25 (m, 2H), 2.8 (t, 2H), 1.85 (d, 2H), 1.6-1.2 (complex m, 7H).
Step 5: cis-2-(4-Phenethyloxy-cyclohexyl)-methylamine
1.5 mL of triethylamine, in 60 mL of dichloromethane was added 1.5 mL of methane-sulfonyl chloride drop-wise over 10 min. The mixture was allowed to stir for 30 min, then concentrated under reduced pressure and diluted with 50 mL of ether and washed with 25 mL of 10% HCI, 25 mL of water, 25 mL of saturated sodium carbonate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. The crude mesylate, 1.6 g, was used without further purification: IH NMR (400 MHz, CDC13) 7.2 (m, 5H), 4.0 (d, 2H), 3.6 (m, 3H),
3.0 (s, 3H), 2.85 (t, 2H), 1.95 (d, 2H), 1.8-1.2 (complex m, 9H). The mesylate was taken up in 20 mL of DMF and heated to reflux with 2 g of sodium azide to 80°C overnight, cooled, filtered, and concentrated under reduced pressure (bath temp = 60°C) to remove most of the DMF. The residue was diluted with 50 mL of ether and washed with 2 x 50 mL of water, dried over magnesium sulfate and concentrated under reduced pressure. The crude azide, 1.5 g, was used without further purification: IH NMR (400 MHz, CDC13) 7.2 (m, 5H), 3.6 (t, 2H), 3.56 (m, IH),
3.1 (d, 2H), 2.95 (t, 2H), 1.95 (d, 2H), 1.8-1.2 (complex m, 9H). To a stirred, ice cold solution of the crude azide in 12 mL of ethanol was added 0.3 g of sodium borohydride and then 0.9 g of nickel chloride hexahydrate. The resulting black mixture was stirred for 2 h, diluted with 50 mL of saturated sodium carbonate and extracted with 3 x 50 mL of chloroform. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. Drying under vacuum gave 1.45 g of a thick oil: MS (m+1) = 235.2, IH NMR (400 MHz, CDC13) 7.2 (m, 5H), 3.6 (t, 2H), 3.55 (m, IH), 2.88 (t, 2H), 1.85 (d, 2H), 1.7-1.2 (complex m, 7H).
46 -
A mixture of 0.3 g of cis-2-(4-phenethyloxy-cyclohexyl)-methylamine, 0.2 g of 4- chloro-lH-pyrazolo[3,4-d]pyrimidine (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790 (1956)), 10 mL of 2-propanol and 0.2 mL of N,N-diisopropyl-ethylamine was heated to 80°C for 12 hours. The mixture was cooled and concentrated under reduced pressure and purified by preparative TLC eluting with 80:20:5 THF: diethyl ether: NH40H and preparative reverse phase chromatography on ChiralPak AD eluting with 80:20 hexane (0.1% diethylamine): ethanol gave 0.22 g of product as a white crystalline solid. MS (m+1) = 352.3; IH NMR (400 MHz, CDC13) 8.4 (s, IH), 7.92 (s, IH), 7.2 (m, 5H), 3.6 (t, 2H), 3.55 (m, IH), 3.5 (m, 2H), 2.85 (t, 2H), 1.9 (m, 2H), 1.7 (m, IH), 1.8-1.5 (m, 5H), 1.4 (m, 4H).
Example 12
trans-(4-Phenethyloxymethyl-cvclohexyl)-(lH-pyrazolo[3,4-dlpyrimidin-4-vI)-amine
Step 1 : cis-4-Methanesulfonyloxy-cvclohexaneearboxylic acid ethyl ester
- 47 -
10% HCI, 25 mL of water, 25 mL of saturated sodium carbonate. The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. The crude mesylate, 2.5 g, was used without further purification: IH NMR (400 MHz, CDC13) 4.92 (m, IH), 4.15 (q, 2H), 3.02 (s, 3H), 2.4 (m, IH), 2.05 (m, 2H), 1.92 (m, 2H), 1.62-1.4 (complex m, 4H).
Step 2: cis-4-Methanesulfonic acid 4-hydroxymethyl-cyclohexyl ester
To a stirred solution of 2.5g of cis-4-methanesulfonyloxy-cyclohexanecarboxylic acid ethyl ester in 30 mL of 1, 2-dimethoxyethane was added 10 mL of IM lithium borohydride in THF. The mixture was allowed to stir for overnight, then cooled in an ice bath and quenched by careful addition of 100 mL of 2N HCI and extracted into 3 x 50 mL portions of ethyl acetate. The combined extracts were and washed with 25 mL of saturated sodium carbonate, dried over magnesium sulfate, diluted with 50 mL of toluene and concentrated under reduced pressure. The crude hydroxy-mesylate, 1.8 g, was used without further purification: IH NMR (400 MHz, CDC13) 5.0 (m, IH), 4.15 (m, IH), 3.6 (m, 2H), 3.02 (s, 3H), 2.05 (m, 2H), 1.92 (m, IH), 1.6 (complex m, 4H), 1.4 (dd, 2H).
Step 3: cis-Methanesulfonic acid 4-(tert-butyl-dimethyl-silanyloxymethyl-cyclohexyl ester
48
Step 4: cis-Methanesulfonic acid 4-phenethyloxymethyl-cvclohexyl ester
From 0.9 g of cis-methanesulfonic acid 4-(tert-butyl-dimethyl-silanyloxymethyl- cyclohexyl ester, 20 mL of anhydrous acetonitrile, 2.6 mL of triethyl silane, 1.6 mL of phenyl- acetaldehyde and 0.25 g of bismuth tribromide using the procedure described for Example 1, Step 3 above (chromatography using gradient elution 10%-35% ethyl acetate in hexane), gave 0.8 g of a colorless resin: IH NMR (400 MHz, CDC13) 7.3-7.2 (m, 5H), 5.0 (m, IH), 3.62 (t, 2H), 3.28 (d, 2H), 3.0 (s, 3H), 2.88 (t, 2H), 2.05 (m, 2H), 1.65 (m, 4H), 1.58 (m, IH), 1.4 (m, 2H).
Step 5: trans-4-Phenethyloxymethyl-cyclohexylamine
A mixture of 0.8 g of the crude azide and 0.2 g of 10% palladium on carbon in 50 mL of ethanol was stirred under 1 atm of hydrogen for 4 h, filtered and concentrated under reduced pressure. Drying under vacuum gave 0.8 g of a thick oil: MS (m+1) = 235.1, IH NMR (400 MHz, CDC13) 7.25-7.2 (m, 5H), 3.6 (t, 2H), 3.22 (d, 2H), 2.88 (t, 2H), 2.6 (m, IH), 1.84 (d, 2H), 1.8 (d, 2H), 1.5 (m, IH), 1.0 (m, 4H).
49 -
Step 6 : frans-(4-Phenethyloxymethyl-cvclohexyl 1 H-pyrazolo \3 ,4-dlpyrimidin-4-yl)-amine
A mixture of 0.13 g of trans-4-phenethyloxymethyl-cyclohexylamine (Compound 45), 0.08 g of 4-chloro-lH-pyrazolo[3,4-d]pyrimidine (R.K. Robins, J. Amer. Chem. Soc, 78, 784-790
(1956)), 10 mL of 2-propanol and 0.1 mL of N,N-diisopropyl-ethylamine was heated to 80°C for 12 hours. The mixture was cooled and concentrated under reduced pressure and purified by preparative TLC eluting with 90:10 THF: NH40H: gave 0.15 g of product as a white crystalline solid. MS (m+1) = 352.1; IH NMR (400 MHz, CDC13) 8.4 (s, IH), 7.92 (s, IH), 7.3-7.2 (m, 5H), 3.62 (t, 2H), 3.55 (m, IH), 3.3 (d, 2H), 2.9 (t, 2H), 2.2 (d, 2H), 2.1 (s, IH), 1.9 (d, 2H), 1.6 (m, IH), 1.3 (m, 2H), 1.2 (dd, 2H).
50
Claims
WHAT IS CLAIMED IS:
A compound having the formula (la):
(la) wherein:
Rl is 
, unsubstituted or substituted with halogen or -R2, where R2 is Cι. 6alkyl, independently unsubstituted or substituted with one or more halogen;
Y is -Ci-6alkyl, independently unsubstituted or substituted with one or more halogen; and pharmaceutically acceptable salts thereof and individual enantiomers and diastereomers thereof.
2. A compound selected from:
51 - 
52 ■
3. A pharmaceutical composition comprising an inert carrier and a therapeutically effective amount of a compound according to Claim 1.
4. The pharmaceutical composition according to Claim 3, further comprising a second therapeutic agent selected from the group consisting of: (i) non-steroidal anti-inflammatory agents; (ii) COX-2 inhibitors; (iii) bradykinin Bl receptor antagonists; (iv) sodium channel blockers and antagonists; (v) nitric oxide synthase (NOS) inhibitors; (vi) glycine site antagonists; (vii) potassium channel openers; (viii) AMPA/kainate receptor antagonists; (ix) calcium channel antagonists; (x) GABA-A receptor modulators (e.g., a GABA- A receptor agonist); (xi) matrix metalloprotease (MMP) inhibitors; (xii) thrombolytic agents; (xiii) opioids such as morphine; (xiv) neutrophil inhibitory factor (NIF); (xv) L-Dopa; (xvi) carbidopa; (xvii) levodopa/carbidopa; (xviii) dopamine agonists such as bromocriptine, pergolide, pramipexole, ropinirole; (xix) anticholinergics; (xx) amantadine; (xxi) carbidopa; (xxii) catechol O- methyltransferase ("COMT") inhibitors such as entacapone and tolcapone; (xxiii) Monoamine oxidase B ("MAO-B") inhibitors; (xiv) opiate agonists or antagonists; (xv) 5HT receptor agonists or antagonists; (xvi) NMDA receptor agonists or antagonists; (xvii) NK1 antagonists; (xviii) selective serotonin reuptake inhibitors ("SSRI") and/or selective serotonin and norepinephrine reuptake inhibitors ("SSNRI"); (xxix) tricyclic antidepressant drugs, (xxx) norepinephrine modulators; (xxxi) lithium; (xxxii) valproate; and (xxxiii) neurontin (gabapentin).
5. The pharmaceutical composition according to Claim 3 useful for the treatment of pain, Parkinson's disease, Alzheimer's disease, epilepsy, depression, anxiety, and ischemic brain injury including stroke.
6. The pharmaceutical composition according to Claim 3 useful for the treatment of Parkinson's disease.
7. A method for treating or preventing pain, Parkinson's disease, Alzheimer's disease, epilepsy, depression, anxiety, ischemic brain injury including stroke in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
8. A method for treating or preventing chronic, visceral, inflammatory and neuropathic pain syndromes in a patient in need thereof comprising administering to said patient - 53 - a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
9. A method for treating or preventing pain resulting from, or associated with, traumatic nerve injury, nerve compression or entrapment, postherpetic neuralgia, trigeminal neuralgia, diabetic neuropathy, cancer and chemotherapy, in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
10. A method for treating or preventing chronic lower back pain in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
11. A method for treating or preventing phantom limb pain in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
12. A method for treating or preventing HIV- and HIV treatment-induced neuropathy, chronic pelvic pain, neuroma pain, complex regional pain syndrome, chronic arthritic pain and related neuralgias in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
13. A method for treating or preventing epilepsy and partial and generalized tonic seizures in a patient in need thereof comprising administering to said patient a therapeutically effective amount, or a prophylactically effective amount, of a compound according to Claim 1, or a pharmaceutically acceptable salt thereof.
- 54 -
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Cited By (3)
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| WO2007128056A1 (en) * | 2006-05-03 | 2007-11-15 | Cnsbio Pty Ltd | Methods and composition for treatment of inflammatory pain |
| US8188098B2 (en) | 2008-05-19 | 2012-05-29 | Hoffmann-La Roche Inc. | GPR119 receptor agonists |
| WO2013156614A1 (en) | 2012-04-20 | 2013-10-24 | Ucb Pharma S.A. | Methods for treating parkinson's disease |
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| US4904666A (en) * | 1987-04-15 | 1990-02-27 | Boehringer Mannheim Gmbh | Pyrazolo(3,4-d)pyrimidine compounds, compositions and method of use |
| US5723608A (en) * | 1996-12-31 | 1998-03-03 | Neurogen Corporation | 3-aryl substituted pyrazolo 4,3-d!pyrimidine derivatives; corticotropin-releasing factor receptor (CRF1) specific ligands |
| WO2001023389A2 (en) * | 1999-09-30 | 2001-04-05 | Neurogen Corporation | Certain alkylene diamine-substituted heterocycles |
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| US4904666A (en) * | 1987-04-15 | 1990-02-27 | Boehringer Mannheim Gmbh | Pyrazolo(3,4-d)pyrimidine compounds, compositions and method of use |
| US5723608A (en) * | 1996-12-31 | 1998-03-03 | Neurogen Corporation | 3-aryl substituted pyrazolo 4,3-d!pyrimidine derivatives; corticotropin-releasing factor receptor (CRF1) specific ligands |
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| RIDEOUT, JANET L., KRENITSKY, THOMAS A., KOSZALKA, GEORGE W., COHN, NAOMI K. ET AL.: "Pyrazolo[3,4-d]pyrimidine Ribonucleosides as Anticoccidials. 2. Synthesis and Activity of Some Nucleosides of 4-(Alkylamino)-1H-pyrazolo[3,4-d]pyrimidines", J. MED. CHEM., vol. 25, 1982, pages 1040 - 1044, XP002306569 * |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2007128056A1 (en) * | 2006-05-03 | 2007-11-15 | Cnsbio Pty Ltd | Methods and composition for treatment of inflammatory pain |
| US8188098B2 (en) | 2008-05-19 | 2012-05-29 | Hoffmann-La Roche Inc. | GPR119 receptor agonists |
| WO2013156614A1 (en) | 2012-04-20 | 2013-10-24 | Ucb Pharma S.A. | Methods for treating parkinson's disease |
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