Patent Application
20070155783
The present invention relates to novel substituted cyclohexyl and piperidinyl derivatives as melanocortin-4 receptor modulators. Depending on the structure and the stereochemistry, the compounds of the invention are either selective agonists or selective antagonists of the human melanocortin-4 receptor (MC-4R). The agonists can be used for the treatment of disorders and diseases such as obesity, diabetes and sexual dysfunction, whereas the antagonists are useful for the treatment of disorders and diseases such as cancer cachexia, muscle wasting, anorexia, anxiety and depression. Generally, all diseases and disorders where the regulation of the MC-4R is involved can be treated with the compounds of the invention.
Melanocortins (MCs) stem from pro-opiomelanocortin (POMC) via proteolytic cleavage. These peptides, adrenocorticotropic hormone (ACTH), α-melanocyte-stimulating hormone (α-MSH), β-MSH and γ-MSH, range in size from 12 to 39 amino acids. The most important endogenous agonist for central MC-4R activation appears to be the tridecapeptide α-MSH. Among MCs, it was reported that α-MSH acts as a neurotransmitter or neuromodulator in the brain. MC peptides, particularly α-MSH, have a wide range of effects on biological functions including feeding behavior, pigmentation and exocrine function. The biological effects of α-MSH are mediated by a sub-family of 7-transmembrane G- protein-coupled receptors, termed melanocortin receptors (MC-Rs). Activation of any of these MC-Rs results in stimulation of cAMP formation.
To date, five distinct types of receptor subtypes for MC (MC-1R to MC-5R) have been identified and these are expressed in different tissues.
MC-1R was first found in melanocytes. Naturally occurring inactive variants of MC-1R in animals were shown to lead to alterations in pigmentation, and a subsequent lighter coat color, by controlling the conversion of phaeomelanin to eumelanin through the control of tyrosinase. From these and other studies, it is evident that MC-1R is an important regulator of melanin production and coat color in animals and skin color in humans.
The MC-2R is expressed in the adrenal gland representing the ACTH receptor. The MC-2R is not a receptor for α-MSH but is the receptor for the adrenocorticotropic hormone I (ACTH I).
The MC-3R is expressed in the brain (predominately located in the hypothalamus) and peripheral tissues like gut and placenta, and knock-out studies have revealed that the MC-3R may be responsible for alterations in feeding behavior, body weight and thermogenesis.
The MC4R is primarily expressed in the brain. Overwhelming data support the role of MC-4R in energy homeostasis. Genetic knock-outs and pharmacologic manipulation of MC-4R in animals have shown that agonizing the MC-4R causes weight loss and antagonizing the MC-4R produces weight gain (A. Kask, et al., “Selective antagonist for the melanocortin-4 receptor (HS014) increases food intake in free-feeding rats,” Biochem. Biophys. Res. Commun., 245: 90-93 (1998)).
MC-5R is ubiquitously expressed in many peripheral tissues including white fat and placenta, and a low level of expression is also observed in the brain. However its expression is greatest in exocrine glands. Genetic knock-out of this receptor in mice results in altered regulation of exocrine gland function, leading to changes in water repulsion and thermoregulation. MC-5R knockout mice also reveal reduced sebaceous gland lipid production (Chen et al., Cell, 91: 789-798 (1997)).
Attention has been focused on the study of MC-3R and MC-4R modulators and their use in treating body weight disorders, such as obesity and anorexia. However, evidence has shown that the MC peptides have potent physiological effects besides their role in regulating pigmentation, feeding behavior and exocrine function. In particular, α-MSH recently has been shown to induce a potent anti-inflammatory effect in both acute and chronic models of inflammation including inflammatory bowel-disease, renal ischemia/reperfusion injury and endotoxin-induced hepatitis. Administration of α-MSH in these models results in substantial reduction of inflammation-mediated tissue damage, a significant decrease in leukocyte infiltration and a dramatic reduction in elevated levels of cytokines and other mediators, to near baseline levels. Recent studies have demonstrated that the anti-inflammatory actions of α-MSH are mediated by MC-1R. The mechanism by which agonism of MC-1R results in an anti-inflammatory response is likely through inhibition of the pro-inflammatory transcription activator, NF-kB. NF-kB is a pivotal component of the pro-inflammatory cascade and its activation is a central event in initiating many inflammatory diseases. Additionally, anti-inflammatory actions of α-MSH may be, in part, mediated by agonism of MC-3R and/or MC-5R.
A specific single MC-R, that may be targeted for the control of obesity, has not yet been identified, although evidence has been presented that MC-4R signaling is important in mediating feeding behavior (S. Q. Giraudo et al., “Feeding effects of hypothalamic injection of melanocortin-4 receptor ligands,” Brain Research, 80: 302-306 (1998)). Further evidence for the involvement of MC-R's in obesity includes: 1) the agouti (Avy) mouse, which ectopically expresses an antagonist of the MC-1R, MC-3R and MC-4R, is obese, indicating that blocking the action of these three MC-R's can lead to hyperphagia and metabolic disorders; 2) MC-4R knockout mice (D. Huszar et al., Cell, 88: 131-141 (1997)) recapitulate the phenotype of the agouti mouse and these mice are obese; 3) the cyclic heptapeptide melanotanin II (MT-II) (a non-selective MC-1R, -3R, -4R and -5R agonist) injected intracerebroventricularly (ICV) in rodents, reduces food intake in several animal feeding models (NPY, ob/ob, agouti, fasted), while ICV injected SHU-9119 (MC-3R and -4R antagonist; MC-1R and -5R agonist) reverses this effect and can induce hyperphagia; 4) chronic intraperitoneal treatment of Zucker fatty .rats with an α-NDP-MSH derivative (HP-228) has been reported to activate MC-1R, -3R, -4R and -5R and to attenuate food intake and body weight gain over a 12 week period (I. Corcos et al., “HP-228 is a potent agonist of melanocortin receptor4 and significantly attenuates obesity and diabetes in Zucker fatty rats”, Society for Neuroscience Abstracts, 23: 673 (1997)).
MC-4R appears to play a role in other physiological functions as well, namely controlling grooming behavior, erection and blood pressure. Erectile dysfunction denotes the medical condition of inability to achieve penile erection sufficient for successful intercourse. The term “impotence” is often employed to describe this prevalent condition. Synthetic melanocortin receptor agonists have been found to initiate erections in men with psychogenic erectile dysfunction (H. Wessells et al., “Synthetic Melanotropic Peptide Initiates Erections in Men With Psychogenic Erectile Dysfunction: Double-Blind, Placebo Controlled Crossover Study”, J. Urol., 160: 389-393, 1998). Activation of melanocortin receptors of the brain appears to cause normal stimulation of sexual arousal. Evidence for the involvement of MC-R in male and/or female sexual dysfunction is detailed in WO/0074679.
Diabetes is a disease in which a mammal's ability to regulate glucose levels in the blood is impaired because the mammal has a reduced ability to convert glucose to glycogen for storage in muscle and liver cells. In “Type I diabetes”, this reduced ability to store glucose is caused by reduced insulin production. “Type II diabetes”, or “Non-Insulin Dependent Diabetes Mellitus” (NIDDM), is the form of diabetes which is due to a profound resistance to insulin stimulating or regulatory effect on glucose and lipid metabolism in the main insulin-sensitive tissues, muscle, liver and adipose tissue. This resistance to insulin responsiveness results in insufficient insulin activation of glucose uptake, oxidation and storage in muscle, and inadequate insulin repression of lipolysis in adipose tissue, and of glucose production and secretion in liver. When these cells become desensitized to insulin, the body tries to compensate by producing abnormally high levels of insulin, and hyperinsulemia results. Hyperinsulemia is associated with hypertension and elevated body weight. Since insulin is involved in promoting the cellular uptake of glucose, amino acids and triglycerides from the blood by insulin sensitive cells, insulin insensitivity can result in elevated levels of triglycerides and LDL, which are risk factors in cardiovascular diseases. The constellation of symptoms which includes hyperinsulemia combined with hypertension, elevated body weight, elevated triglycerides and elevated LDL, is known as Syndrome X. MC-4R agonists might be useful in the treatment of NIDDM and Syndrome X.
Among MC receptor subtypes, the MC4 receptor is also of interest in terms of the relationship to stress and the regulation of emotional behavior, as based on the following findings. Stress initiates a complex cascade of responses that include endocrine, biochemical and behavioral events. Many of these responses are initiated by release of corticotropin-releasing factor (CRF), (Owen M J and Nemeroff C B (1991), (Physiology and pharmacology of corticotrophin releasing factor. Pharmacol Rev 43:425-473). In addition to activation of the brain CRF system, there are several lines of evidence that melanocortins (MCs), which stem from proopiomelanocortin by enzymatic processing, mediate important behavioral and biochemical responses to stress and, consequently, stress-induced disorders like anxiety and depression (Anxiolytic-Like and Antidepressant-Like Activities of MCL0129 (1-[(S)-2-(4-Fluorophenyl)-2-(4-isopropylpiperadin-1-yl)ethyl]4-[4-(2-methoxynaphtalen-1-yl)butyl]piperazine), a Novel and Potent Nonpeptide Antagonist of the Melanocortin-4 Receptor; Shigeyuki Chaki et al, J. Pharm. Exp. Ther. (2003)304(2), 818-26).
Chronic diseases, such as malignant tumors or infections, are frequently associated with cachexia, resulting from a combination of a decrease in appetite and a loss of lean body mass. Extensive loss of lean body mass is often triggered by an inflammatory process and is usually associated with increased plasma levels of cytokines (e.g. TNF-α), which increase the production of α-MSH in the brain. Activation of MC4 receptors in the hypothalamus, by α-MSH, reduces appetite and increases energy expenditure. Experimental evidence, in tumor bearing mice, suggests that cachexia can be prevented or reversed by genetic MC4 receptor knockout or MC4 receptor blockade. The increased body weight in the treated mice is attributable to a larger amount of lean body mass, which mainly consists of skeletal muscle (Marks D. L. et al. Role of the central melanocortin system in cachexia. Cancer Res. (2001) 61: 1432-1438).
WO03009847A1 describes substituted piperidines as modulators of the melanocortin receptor for the treatment of obesity. Substituted 4-phenylpiperidine is acylated with phenylalanine followed by acylation of the α-amino group with amino acids, carboxylic acids or sulfonyl chlorides. Biological data are not provided.
WO02059117A1 describes piperazine- and piperidine-derivatives as melanocortin receptor agonists for the treatment of obesity, diabetes and male and/or female sexual dysfunction. The title compounds consist of phenylpiperazinyl-phenylalanine amides and phenylpiperidinyl-phenylalanine amides which are acylated or alkylated at the N-terminus using amino acid derivatives. No biological data are given in the patent.
WO0207051 1Al describes phenylpiperazinyl-phenylalanine amides, phenylpiperidinyl-phenylalanine amides and cyclohexyl-phenylalanine amides as modulators of melanocortin receptors 1 and 4. The phenylalanine amino group is in the most cases acylated with a second amino acid. For amino acids with a basic side chain the amino group can be acylated. Biological data for the compounds are not given.
The cited patents have in common that the piperidine or piperazine and the phenylalanine are coupled by an amide bond formation. However, compounds where the the piperidine or piperazine part of the molecule is linked to the phenylalanine via a C-C bond have not been described.
In view of the unresolved deficiencies in the treatment of various diseases and disorders as discussed above, it is an object of the present invention to provide novel substituted cyclohexyl and piperidinyl derivatives with improved ability to cross the blood brain barrier, which are useful as melanocortin-4 receptor modulators to treat cancer cachexia, muscle wasting, anorexia, anxiety, depression, obesity, diabetes, sexual dysfunction and other diseases with MC-4R involvement.
Also provided are processes for producing the MC-4R modulators and pharmaceutical compositions containing the same.
The present invention relates to novel-substituted piperidyl and cyclohexyl derivatives of structural formula (I).
The present invention relates to compounds of formula (I)
wherein the variables R1, R2, R3, R4, X, n, o and p have the meaning as defined below.
The piperidyl and cyclohexyl derivatives of structural formula (I) are effective as melanocortin receptor modulators and are particularly effective as selective melanocortin-4 receptor (MC-4R) modulators. They are therefore useful for the treatment of disorders where the activation or inactivation of the MC-4R are involved. Agonists can be used for the treatment of disorders and diseases such as obesity, diabetes and sexual dysfunction, whereas the antagonists are useful for the treatment of disorders and diseases such as cancer cachexia, muscle wasting, anorexia, anxiety and depression.
The present invention also relates to the intermediate compound of structural formula (II)
wherein the variables R1, R3, R4, X, n, o and p have the meaning as defined below.
Moreover, the present invention also relates to pharmaceutical compositions comprising the compounds of the present invention and a pharmaceutically acceptable carrier.
The present invention relates to novel-substituted piperidinyl and cyclohexyl derivatives useful as melanocortin receptor modulators, in particular, selective MC-4R agonists and MC-4R antagonists.
Compounds of the present invention are represented by structural formula (I)
or a pharmaceutically acceptable salt or a solvate thereof, wherein R1, is independently:
In preferred embodiments, the variants have the following meanings:
R1 is as defined above wherein heterocyclyl includes azetidin-2-one-1-yl, pyrrolidin-2-one-1-yl, piperid-2-one-1-yl and azepan-2-one-1-yl. Moreover, alkyl, alkoxy, cycloalkyl, aryl, heterocyclyl and heteroaryl are preferably substituted or unsubstituted alkyl with one to five, preferably 1 to 3, more preferably 1 or 2, substituents independently selected from R14.
Preferably, R1 is hydrogen, hydroxy, cyano, nitro, halo, alkyl, alkoxy, haloalkyl, (D)-N(R15)2, (D)-NR15COR15, (D)-NR15CON(R15)2, (D)-NR15C(O)OR15, (D)-NR15C(R5)═N(R15), (D)-NR15C(═NR15)N(R15)2, (D)-NR15SO2R15, (D)-NR15SO2N(R15)2 or (D)-heterocyclyl, wherein alkyl or alkoxy are substituted or unsubstituted with one to five, preferably one to three, substituents selected from R14. More preferably, R1 is cyano, nitro, halo, alkyl, (D)-heterocyclyl, (D)-N(R15)2, (D)-NR15COR15, (D)-NR15CON(R15)2, (D)-NR15C(O)OR15 or (D) -NR15SO2R15. Most preferably, R1 is halo, (D)-heterocyclyl, (D)-NR15SO2R15, (D) -NR15CON(R15)2 or (D)-NR15COR15, in particular (D)-heterocyclyl. Halo is preferably F, Cl or Br. R1 can be on any position of the ring, preferably in the 1-position.
R3 is as defined above and is preferably (CH2)-aryl or (CH2)-heteroaryl, more preferably (CH2)-aryl, most preferably (CH2)-phenyl or (CH2)-naphthyl. If aryl or heteroaryl are substituted, it is preferably substituted with one to three, more preferably 1 or 2, most preferably 1, substituents. The substituents are preferably independently selected from the group consisting of cyano, nitro, perfluoroalkoxy, halo, alkyl, (D)-cycloalkyl, alkoxy and haloalkyl, more preferably selected from perfluoroalkoxy, halo, alkyl, alkoxy or haloalkyl, most preferably selected from halo, alkyl, alkoxy and haloalkyl, in particular halo.
More preferably, R3 is (CH2)-phenyl or (CH2)-naphthyl which both, preferably (CH2)-phenyl, may be substituted with one to three, in particular one, halo, e.g. Cl. The substitution can be in any position, preferably in the 4-position.
R4 is as described above. In one embodiment R4 is a bond.
R5 is as defined above wherein aryl, heteroaryl, heterocyclyl, alkyl or cycloalkyl is preferably unsubstituted or substituted with one to three substituents selected from the group consisting of halo, oxo, alkyl, N(R6)2, OR6, SR6 and CO2R6. Preferably, R5 is hydrogen, halo, alkyl, haloalkyl, hydroxy, alkoxy, S-alkyl, SO2-alkyl, O-alkenyl or S-alkenyl, more preferably hydrogen, halo, hydroxy, alkoxy, S-alkyl, SO2-alkyl or alkyl, e.g. methyl, ethyl, n-propyl, isopropyl, most preferably hydrogen, hydroxy, iso-propyl, alkoxy, S-alkyl or SO2-alkyl.
In one embodiment the one to three substituents are selected from the group consisting of oxo, alkyl, N(R6)2, OR6, SR6 and CO2R6. In one embodiment each R5 is independently hydrogen, halo, alkyl, haloalkyl, (D)-cycloalkyl or (D)-aryl (wherein aryl is phenyl or naphthyl), (D)-heteroaryl or (D)-heterocyclyl (wherein heterocyclyl excludes a heterocyclyl containing a single nitrogen), and wherein aryl, heteroaryl, heterocyclyl, alkyl or cycloalkyl is unsubstituted or substituted Preferably, R5 is hydrogen, halo, alkyl, haloalkyl, alkoxy or (D)cycloalkyl, more preferably hydrogen, halo or alkyl, e.g. methyl, ethyl, n-propyl, iso-propyl, most preferably hydrogen, hydroxy.
R6 is as defined above, preferably hydrogen or alkyl, e.g. methyl, ethyl, n-propyl, iso-propyl, more preferably hydrogen.
R7 is as defined above, preferably hydrogen, (D)-aryl, (D)-heteroaryl, (D)-N(R9)2, (D)-NR9C(O)alkyl, (D)-NR9SO2alkyl or alkyl, e.g. methyl, ethyl, n-propyl, iso-propyl, more preferably hydrogen.
R8 is as defined above, preferably hydrogen or alkyl, e.g. methyl, ethyl, n-propyl, iso-propyl, more preferably hydrogen.
R9 and R10 are each independently as defined above. When R9 and R10 form a ring, the ring preferably contains an additional heteroatom selected from O, S and NR6. R9 and R10 are each independently preferably selected from the group consisting of hydrogen, alkyl or cycloalkyl, or R9 and R10 together with the nitrogen to which they are attached form a 5- to 7-membered ring optionally containing an additional heteroatom selected from O, S and NR6. Moreover, alkyl and cycloalkyl are preferably unsubstituted or substituted with one to three, preferably one or two, groups independently selected from R11 and oxo.
More preferably R9 and R10 are each independently selected from the group consisting of hydrogen or alkyl, or R9 and R10 together with the nitrogen to which they are attached form a 5- to 6-membered ring optionally containing an additional oxygen atom.
The above mentioned R11 is alkyl, (D)-aryl, (D)-cycloalkyl, (D)-heteroaryl, halo, OR12, NHSO2R12, N(R12)2, C≡N, CO2R9, C(R12)(R12)N(R12)2, nitro, SO2N(R12)2, S(O)uR12, CF3 or OCF3; preferably selected from the group consisting of alkyl, OR12, (D)-aryl, (D)-cycloalkyl, (D)-heteroaryl and halo.
R12 is independently hydrogen, alkyl, (D)-aryl or cycloalkyl, preferably hydrogen, (D)-aryl or alkyl, e.g. methyl, ethyl, n-propyl, iso-propyl, more preferably hydrogen or (D)-aryl.
R13 is as defined above, preferably hydrogen or C1-C4 alkyl as defined below, more preferaby hydrogen, methyl or ethyl, most preferably hydrogen or methyl.
The above mentioned R14 is independently hydrogen, halo, oxo, N(R6)2, alkyl, (D)-cycloalkyl, haloalkyl, alkoxy, heteroaryl, hydroxy or heterocyclyl, wherein heterocyclyl excludes a heterocyclyl containing a single nitrogen, aryl, (D)-COR15, (D)-C(O)OR15, (D)-OR15, (D)-OCOR15, (D)-OCO2R15, (D)-SR15, (D)-SOR15 or (D)-SO2R15, wherein aryl, heteroaryl, heterocyclyl, alkyl or cycloalkyl are preferably substituted or unsubstituted with one to three, preferably one or two, substituents selected from the group consisting of oxo, alkyl, N(R15)2, OR15, SR15 and CO2R15. Preferably, R14 is hydrogen, halo, alkyl, (D)-cycloalkyl, alkoxy or phenyl, more preferably R14 is hydrogen, halo, alkyl, alkoxy or phenyl.
R15 is as defined above wherein aryl, heteroaryl, heterocyclyl, alkyl or cycloalkyl are preferably substituted or unsubstituted with one to three, preferably one or two, substituents selected from the group consisting of oxo, alkyl, N(R6)2, OR6, SR6 and CO2R6. Preferably, R15 is hydrogen, haloalkyl, alkyl, (D)-cycloalkyl, alkoxy or phenyl, more preferably R15 is hydrogen, haloalkyl, alkyl, alkoxy or phenyl.
Cy is as defined above and preferably selected from aryl, 5- or 6-membered heteroaryl, 5- or 6-membered heterocyclyl and 5- to 7-membered carbocyclyl. More preferably, Cy is aryl and heteroaryl. In one embodiment, Cy may be aryl, such as phenyl or naphthyl.
In the above, any of the preferred definitions for each variant can be combined with the preferred definition of the other variants.
In one embodiment the following combination is contemplated:
In another embodiment the following combination is contemplated:
In the above and the following, the employed terms have the meaning as described below:
Aryl is an aromatic mono- or polycyclic moiety with 6 to 20 carbon atoms which is preferably selected from phenyl, biphenyl, naphthyl, tetrahydronaphthyl, fluorenyl, indenyl or phenanthrenyl, more preferably phenyl or naphthyl.
Heteroaryl is an aromatic moiety having 6 to 20 carbon atoms with at least one heterocycle and is preferably selected from thienyl, benzothienyl, naphthothienyl, furanyl, benzofuranyl, chromenyl, indolyl, isoindolyl, indazolyl, quinolyl, isoquinolyl, phthalazinyl, quinoxalinyl, cinnolinyl or quinazolinyl, more preferably thienyl, furanyl, benzothienyl, benzofuranyl or indolyl.
Heterocyclyl is a saturated, unsaturated or aromatic ring containing at least one heteroatom selected from O, N and/or S and 1 to 6 carbon atoms and is preferably selected from azetidin-2-one-1-yl, pyrrolidin-2-one-1-yl, piperid-2-one-1-yl, azepan-2-one-1-yl, thienyl, furyl, piperidinyl, pyranyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazolyl, isothiazolyl or isoxazyl, more preferably pyridyl, piperidinyl, triazolyl, imidazolyl or pyrazinyl.
Carbocyclyl is a monocyclic or polycyclic ring system of 3 to 20 carbon atoms which may be saturated, unsaturated or aromatic.
Alkyl is straight chain or branched alkyl having preferably 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl or heptyl, more preferably 1 to 4 carbon atoms.
Cycloalkyl is an alkyl ring having preferably 3 to 8 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl, more preferably 3 to 6 carbon atoms.
Alkenyl is straight chain or branched alkenyl having preferably 2 to 8 carbon atoms such as vinyl, allyl, methallyl, buten-2-yl, buten-3-yl, penten-2-yl, penten-3-yl, penten4-yl, 3-methyl-but-3-enyl, 2-methyl-but-3-enyl, 1-methyl-but-3-enyl, hexenyl or heptenyl, more preferably 2 to 4 atoms.
Alkoxy is O-alkyl wherein alkyl is as defined above and has preferably 1 to 4 carbon atoms, more preferably 1 or 3 carbon atoms.
Halo or halogen is a halogen atom preferably selected from F, Cl, Br and I, preferably F, Cl and Br.
Haloalkyl is an alkyl moiety as defined above having preferably 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, wherein at least one, preferably 1 to 3 hydrogen atoms have been replaced by a halogen atom. Preferred examples are —CF3, —CH2CF3 and —CF2CF3.
Therein, the alkylene moiety may be a straight chain or branched chain group. Said alkylene moiety preferably has 1 to 6 carbon atoms. Examples thereof include methylene, ethylene, n-propylene, -n-butylene, n-pentylene, n-hexylene, iso-propylene, sec.-butylene, tert.-butylene, 1,1-dimethyl propylene, 1,2-dimethyl propylene, 2,2-dimethyl propylene, 1,1-dimethyl butylene, 1,2-dimethyl butylene, 1,3-dimethyl butylene, 2,2-dimethyl butylene, 2,3-dimethyl butylene, 3,3-dimethyl butylene, 1-ethyl butylene, 2-ethyl butylene, 3-ethyl butylene, 1-n-propyl propylene, 2-n-propyl propylene, 1-iso-propyl propylene, 2-iso-propyl propylene, 1-methyl pentylene, 2-methyl pentylene, 3-methyl pentylene and 4-methyl pentylene. More preferably, said alkylene moiety has 1 to 3 carbon atoms, such as methylene, ethylene, n-propylene and iso-propylene. Most preferred is methylene.
The compounds of structural formula (I) are effective as melanocortin receptor modulators and are particularly effective as selective modulators of MC-4R. They are therefore useful for the treatment and/or prevention of disorders responsive to the activation and inactivation of MC-4R, such as cancer cachexia, muscle wasting, anorexia, anxiety, depression, obesity, diabetes, sexual dysfunction and other diseases with MC-4R involvement.
Optical Isomers—Diastereomers—Geometric Isomers—Tautomers
Compounds of structural formula (I) contain one or more asymmetric centers and can occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. The present invention is meant to comprehend all such isomeric forms of the compounds of structural formula (I).
Some of the compounds described herein may exist as tautomers such as keto-enol tautomers. The individual tautomers, as well as mixtures thereof, are encompassed within the compounds of structural formula (I).
Compounds of structural formula (I) may be separated into their individual diastereoisomers by, for example, fractional crystallization from a suitable solvent, for example, methanol or ethyl acetate or a mixture thereof, or via chiral chromatography using an optically active stationary phase. Absolute stereochemistry may be determined by X-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.
Altematively, any stereoisomer of a compound of the structural formula (I) may be obtained by stereospecific synthesis using optically pure starting materials or reagents of known absolute configuration.
Salts
The term “pharmaceutically acceptable salts” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids, including inorganic or organic bases and inorganic or organic acids. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc and the like. Particularly preferred are the ammonium, calcium, lithium, magnesium, potassium and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary and tertiary amines, substituted amines including naturally occurring substituted amines and cyclic amines, and basic ion exchange resins, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine 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, formic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, malonic, mucic, nitric, pamoic, pantothenic, phosphoric, propionic, succinic, sulfuric, tartaric, p-toluenesulfonic, trifluoroacetic acid and the like. Particularly preferred are citric, fumaric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric and tartaric acids.
It will be understood that, as used herein, references to the compounds of formula (I) are meant to also include the pharmaceutically acceptable salts.
Utility
Compounds of formula (I) are melanocortin receptor modulators and as such are useful in the treatment, control or prevention of diseases, disorders or conditions responsive to the activation or inactivation of one or more of the melanocortin receptors including, but not limited to, MC-1R, MC-2R, MC-3R, MC-4R or MC-5R. Such diseases, disorders or conditions include, but are not limited to, cancer cachexia, muscle wasting, anorexia, anxiety, depression, obesity (by reducing appetite, increasing metabolic rate, reducing fat intake or reducing carbohydrate craving), diabetes mellitus (by enhancing glucose tolerance, decreasing insulin resistance), hypertension, hyperlipidemia, osteoarhrits, cancer, gall bladder disease, sleep apnea, depression, anxiety, compulsion, neuroses, insomnia/sleep disorder, substance abuse, pain, male and female sexual dysfunction (including impotence, loss of libido and erectile dysfunction), fever, inflammation, immune-modulation, rheumatoid arthritis, skin tanning, acne and other skin disorders, neuroprotecitve and cognitive and memory enhancement, including the treatment of Alzheimer's disease.
Some compounds encompassed by formula (I) show highly selective affinity for the melanocortin-4 receptor relative to MC-1R, MC-2R, MC-3R and MC-5R, which makes them especially useful in the prevention and treatment of cancer cachexia, muscle wasting, anorexia, anxiety, depression, obesity, as well as male and/or female sexual dysfunction, including erectile dysfunction. “Male sexual dysfunction” includes impotence, loss of libido and erectile dysfunction. “Female sexual dysfunction” can be seen as resulting from multiple components, including dysfunction in desire, sexual arousal, sexual receptivity and orgasm.
Administration and Dose Rancies
Any suitable route of administration may be employed for providing a mammal, especially a human with an effective dosage of a compound of the present invention. For example, oral, rectal, topical, parenteral, ocular, pulmonary, nasal and the like, may be employed. Dosage forms include tablets, troches, dispersions, suspensions, solutions, capsules, creams, ointments, aerosols and the like. Preferably compounds of formula (I) are administered orally or topically.
The effective dosage of an active ingredient employed may vary depending on the particular compound employed, the mode of administration, the condition being treated and the severity of the condition being treated. Such dosage may be ascertained readily by a person skilled in the art.
When treating cancer cachexia, muscle wasting or anorexia, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.001 milligram to about 100 milligrams per kilogram of body weight, preferably given in a single dose or in divided doses two to six times a day, or in sustained release form. In the case of a 70 kg adult human, the total daily dose will generally be from about 0.07 milligrams to about 3500 milligrams. This dosage regimen may be adjusted to provide the optimal therapeutic response.
When treating obesity, in conjunction with diabetes and/or hyperglycemia, or alone, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.001 milligram to about 100 milligrams per kilogram of body weight, preferably given in a single dose or in divided doses two to six times a day, or in sustained release form. In the case of a 70 kg adult human, the total daily dose will generally be from about 0.07 milligrams to about 3500 milligrams. This dosage regimen may be adjusted to provide the optimal therapeutic response.
When treating diabetes mellitus and/or hyperglycemia, as well as other diseases or disorders for which compounds of formula (I) are useful, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.001 milligram to about 100 milligram per kilogram of animal body weight, preferably given in a single dose or in divided doses two to six times a day, or in sustained release form. In the case of a 70 kg adult human, the total daily dose will generally be from about 0.07 milligrams to about 3500 milligrams. This dosage regimen may be adjusted to provide the optimal therapeutic response.
For the treatment of sexual dysfunction, compounds of the present invention are given in a dose range of 0.001 milligram to about 100 milligram per kilogram of body weight, preferably as a single dose orally or as a nasal spray.
Formulation
The compound of formula (I) is preferably formulated into a dosage form prior to administration. Accordingly, the present invention also includes a pharmaceutical composition comprising a compound of formula (I) and a suitable pharmaceutical carrier.
The present pharmaceutical compositions are prepared by known procedures using well-known and readily available ingredients. In making the formulations of the present invention, the active ingredient (a compound of formula (I)) is usually mixed with a carrier, or diluted by a carrier, or enclosed within a carrier, which may be in the form of a capsule, sachet, paper or other container. When the carrier serves as a diluent, it may be a solid, semisolid or liquid material which acts as a vehicle, excipient or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosol (as a solid or in a liquid medium), soft and hard gelatin capsules, suppositories, sterile injectable solutions and sterile packaged powders.
Some examples of suitable carriers, excipients and diluents include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water syrup, methyl cellulose, methyl, propylhydroxybenzoates, talc, magnesium stearate and mineral oil. The formulations can additionally include lubricating agents, wetting agents, emulsifying and suspending agents, preserving agents, sweetening agents or flavoring agents. The compositions of the invention may be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient.
Preparation of Compounds of the Invention
When describing the preparation of the present compounds of formula (I), the terms “A moiety”, “B moiety” and “C moiety” are used below. This moiety concept is illustrated below:
Preparation of the compounds of the present invention may be carried out via sequential or convergent synthetic routes. The skilled artisan will recognize that, in general, the “B” and “C moieties” of a compound of formula (I) are connected via amide bonds. The skilled artisan can, therefore, readily envision numerous routes and methods of connecting these two moieties via standard peptide coupling reaction conditions.
The phrase “standard peptide coupling reaction conditions” means coupling a carboxylic acid with an amine using an acid activating agent such as EDC, dicyclohexylcarbodiimide and benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate in an inert solvent such as DCM, in the presence of a catalyst such as HOBt. The uses of protective groups for amine and carboxylic acids to facilitate the desired reaction and minimize undesired reactions are well documented. Conditions required to remove protecting groups which may be present can be found in Greene, et al., Protective Groups in Organic Synthesis, John Wiley & Sons, Inc., New York, N.Y. 1991.
Protecting groups like Z, Boc and Fmoc are used extensively in the synthesis, and their removal conditions are well known to those skilled in the art. For example, removal of Z groups can he achieved by catalytic hydrogenation with hydrogen in the presence of a noble metal or its oxide, such as palladium on activated carbon in a protic solvent, such as ethanol. In cases where catalytic hydrogenation is contraindicated by the presence of other potentially reactive functionality, removal of Z can also be achieved by treatment with a solution of hydrogen bromide in acetic acid, or by treatment with a mixture of TFA and dimethylsulfide. Removal of Boc protecting groups is carried out in a solvent such as methylene chloride, methanol or ethyl acetate with a strong acid, such as TFA or HCl or hydrogen chloride gas.
The compounds of formula (I), when existing as a diastereomeric mixture, may be separated into diastereomeric pairs of enantiomers by fractional crystallization from a suitable solvent, such as methanol, ethyl acetate or a mixture thereof. The pair of enantiomers thus obtained may be separated into individual stereoisomers, by conventional means using an optically active acid as a resolving agent. Alternatively, any enantiomer of a compound of the formula (I) may be obtained by stereospecific synthesis using optically pure starting materials or reagents of known configuration.
The compounds of formula (I) of the present invention can be prepared according to the procedures of the following Schemes and Examples, using appropriate materials and are further exemplified by the following specific examples. Moreover, by utilizing the procedures described herein, in conjunction with ordinary skills in the art, additional compounds of the present invention claimed herein can be readily prepared. The compounds illustrated in the examples are not, however, to be construed as forming the only genus that is considered as the invention. The examples further illustrate details for the preparation of the compounds of the present invention. Those skilled in the art will readily understand that known variations of the conditions and processes of the following preparative procedures can be used to prepare these compounds. The instant compounds are generally isolated in the form of their pharmaceutically acceptable salts, such as those described above. The amine-free bases corresponding to the isolated salts can be generated by neutralization with a suitable base, such as aqueous sodium hydrogencarbonate, sodium carbonate, sodium hydroxide and potassium hydroxide, and extraction of the liberated amine-free base into an organic solvent, followed by evaporation. The amine-free base, isolated in this manner, can be further converted into another pharmaceutically acceptable salt by dissolution in an organic solvent, followed by addition of the appropriate acid and subsequent evaporation, precipitation or crystallization. All temperatures are degrees Celsius. Mass spectra (MS) were measured by electron-spray ion-mass spectroscopy.
In the schemes, preparations and examples below, various reagent symbols and abbreviations have the following meanings:
The “A” and the “B moiety” of the compounds of the present invention are coupled using the olefin cross-metathesis reaction (Org. Lett. 1999, 1, 11, 1751-1753).
Generally the terminal olefin derivatives of an “A moiety” and a “B moiety” are reacted with a metathesis catalyst in a suitable solvent such as DCM, at a suitable temperature to yield the corresponding protected A=B alkenes. Suitable catalysts include Grubbs 2nd generation catalyst (Tricyclohexylphosphine[1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidine]ruthenium(IV) dichloride, (Org. Lett. 1999, 1, 6, 953-956) and Hoveyda-Grubbs 2nd generation catalyst ([1,3-Bis-(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][o-isopropoxyphenylmethylene]ruthenium(IV) dichloride, J. Am. Chem. Soc. 1999, 121, 4, 791-799).
For coupling of H-BA with Boc-C—OH, EDC/HOAt, EDC/HOBt or DCC/HOBt can be used.
Generally, the starting material of Boc-protected amine (Boc-BA) can be deprotected in the presence of TFA/CH2Cl2, HCl/EtOAc, HCl/dioxane or HCl in MeOH/Et2O, with or without a cation scavenger, such as dimethyl sulfide (DMS), before being subjected to the coupling procedure. It can be fre-based before being subjected to the coupling procedure or, in some cases, used as the salt.
A suitable solvent, such as CH2C12, DMF, THF or a mixture of the above solvents, can be used for the coupling procedure. A suitable base includes TEA, DIEA, NMM, collidine or 2,6-lutidine. A base may not be needed when EDC/HOBt is used.
Generally after the reaction is completed, the reaction mixture can be diluted with an appropriate organic solvent, such as EtOAc, CH2Cl2 or Et2O, which is then washed with aqueous solutions, such as water, HCl, NaHSO4, bicarbonate, NaH2PO4, phosphate buffer (pH 7), brine or any combination thereof. The reaction mixture can be concentrated and then be partitioned between an appropriate organic solvent and an aqueous solution. The reaction mixture can be concentrated and subjected to chromatography without aqueous workup.
Protecting groups, such as Boc, Z, Fmoc and CF3CO, can be deprotected in the presence of H2/Pd—C, TFA/DCM, HCl/EtOAc, HCl/dioxane, HCl in MeOH/Et2O, NH3/MeOH or TBAF, with or without a cation scavenger, such as thioanisole, ethane thiol and dimethyl sulfide (DMS). The deprotected amines can be used as the resulting salt or are free-based by dissolving in DCM and washed with aqueous bicarbonate or aqueous NaOH. The deprotected amines can also be free-based by ion exchange chromatography.
The alkenes A=B—C—H can be hydrogenated using a catalyst such as Pd/C and an appropriate solvent like methanol at a suitable hydrogen pressure and a capable temperature.
The “A”, “B” and “C moieties” of the present invention, in general, may be prepared from commercially available starting materials via known chemical transformations.
Reaction Schemes for Preparation of “A moiety”
The preparation of “A moiety”, of the compound of formula (I), is illustrated in the reaction schemes below.
m=0-3
As shown in Reaction Scheme 4, the “A moiety” of the compounds of formula (I) can be prepared by reacting various methyl benzenes 1 with NBS in the presence of a radical starter such as Bz2O2, followed by reaction with diethyl phosphite in the presence of a base, such as DIEA, to give benzylbromides 2, which can then used to alkylate lactames like 3 in the presence of an appropriate base, such as KF/alumina. The substituted bromobenzenes can then be subjected to Buchwald conditions. By coupling bromobenzenes 4 with 1,4-dioxa-8-azaspiro[4.5]decane 5 in the presence of tri(dibenzylideneacetone)dipalladium(Pd2(dba)3), 2,2′-Bis(diphenylphosphino)-1,1′-binaphtyl (BINAP) and sodium-tert-butoxide (NaOtBu) or cesium carbonate (Cs2CO3) in an organic solvent, such as toluene, at a suitable temperature.
w=0-2, m=0-3
As shown in Reaction Scheme 5, carboxylic acids 7 can be reduced to the corresponding alcohols 8 using an appropriate reagent, such as BH3-THF, which are subsequently transferred to the corresponding alkyl bromides 9 with reagents such as CBr4 and PPh3. The alkyl bromides can then be used to alkylate lactames, like 3, in the presence of an appropriate base such as KF/alumina. The substituted bromobenzenes can then be subjected to Buchwald conditions to yield compounds 11.
Br—R is compound 4 or 10
As shown in Reaction Scheme 6, 8-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1,4-dioxa-spiro[4.5]dec-7-ene 12 (analog Tetrahedron Lett. 2000, 41, 3705-3708) can be reacted with haloaromates such as 4 or 10, in the presence of a base such as K2CO3 and a catalyst such as dichloro(1,1′-bis(diphenylphosphino)-ferrocene)palladium(II) DCM adduct, in an organic solvent such as DMF, at a suitable temperature. The protected cyclohexenones 13 can be hydrogenated in the presence of a catalyst such as Pd/C, to yield the protected cyclohexanones 14.
X—R═N-subst.-aryl: compounds 6 and 11
X-R═CH-subst.-aryl: compound 14
As shown in Reaction Scheme T, protected ketones 6, 11 and 14 can be deprotected by acid-catalyzed cleavage using an acid suchas HCl or HClO4, in an appropriate solvent such as THF or DCM, at a suitable temperature. Transformation of the ketones 15 to the terminal olefins 16 can be achieved with the Tebbe reagent, in an appropriate solvent such as THF and toluene, at a suitable reaction temperature (Org. Synth. Coll. Vol. 8, 512).
Reaction Schemes for Preparation of “B moiety”
As shown in Reaction Scheme 8, amino acids 17 can be converted into the corresponding Weinreb amides using standard peptide coupling conditions such as EDC/NMM, in an appropriate solvent such as DCM (analog Synth. Commun. 1982, 676). Reduction of the Weinreb amides 18 to the aldehydes 19 can be performed with reagents like LAH, in an appropriate solvent such as diethyl ether (Chirality 2000, 12, 2). Conversion of aldehydes 19: into terminal olefins 20, can be achieved by means of a Wittig reaction: Methyltriphenylphosphonium bromide can be reacted with an amino aldehyde in the presence of a base such as KHDMS, in a appropriate solvent such as THF, at a suitable temperature to yield the corresponding terminal alkenes (J. Org. Chem. 2003, 68, 6, 2432-2436).
Reaction Schemes for Preparation of “C moiety”
As shown in Reaction Scheme 9, ethyl 3-bromo-4-oxochromene-2-carboxylate 21 (J. Chem. Soc. Perkin Trans. I 1986, 1643-1649) can be reacted with amines with or without a base, such as K2CO3, appropriate solvent such as MeCN, to form products 22 which are sebsequently treated with a reagent such as HBr/HOAc to form carboxylic acids 23. When R8 is hydrogen, the free amine can be protected with a reagent such as Boc2O in the presence of TEA and DMAP, in an appropriate solvent.
As shown in Reaction Scheme 10, ethyl 4-oxo-1,4-dihydro-quinoline-2-carboxylates 25 (Bioorg. Med. Chem. Lett. 2000, 10, 1487-1490) can be converted into the corresponding acids 26 by an appropriate reactant such as HBr/HOAc.
As shown in Reaction Scheme 11, substituted phenols 27 can be reacted with triethylamine followed by dimethyl acetylendicarboxylate in diethyl ether to yield compounds 28 (Aust. J. Chem. 1995, 48, 677-686). Saponification of the latter with aqueous sodium hydroxide leads to acids 29 which are subsequently cyclized to the chromone-2-carboxylic acids 30 using concentrated sulfuric acid in acetyl chloride.
As shown in Reaction Scheme 12, 2′-hydroxyacetophenones 31 can be reacted with diethyl oxalate 32 in the presence of a base such as sodium methoxide in an appropriate solvent such as methanol or benzene followed by treatment with an acid such as hydrochloric acid to yield chromone-2-carboxylic acid esters 33 (J. Indian Chem. Soc. 1986, 63, 600-602). The esters can be cleaved using basic conditions such as sodium bicarbonate in water or acidic conditions such as polyphosphoric acid at an appropriate temperature to the corresponding acids 34.
As shown in Reaction Scheme 13, methoxy-substituted chromone-2-carboxylic acids 35 can be demethylated with reagents such as hydroiodic acid in an appropriate solvent such as glacial acetic acid to yield the corresponding hydroxy-substituted chromone-2-carboxylic acids 36.
5,7-Dihydroxychromone-2-carboxylic acid was prepared as described in the literature (OPPI Briefs 1991, 23, 390-392).
The following describes the detailed examples of the invention.
The following examples are provided to illustrate the invention and are not limiting the scope of the invention in any manner.
To Boc-protected intermediate 1 h) (30 mg) in DCM (1 ml) was added TFA (0.2 ml) and the reaction was stirred at 0° C. for 6 h. The reaction mixture was concentrated to dryness. The residue was dissolved in DCM and treated with diethyl ether. The precipitate was filtered off to yield the title compound as a solid.
white solid Rf=0.06 (EtOAc); Mp. 227-228° C.
The required intermediates can be synthesized in the following way:
Intermediate 1a):
To a solution of 2-bromobenzyl bromide (3.05 g) and 2-pyrrolidinone (0.85 g) in DME (20 ml) was added KF-alumina (0.45 g) and the mixture was stirred for 48 h at room temperature. The inorganics were filtered off and the solvent was removed to afford the desired compound.
Intermediate 1b):
To intermediate 1a) (1246 mg) in DMF (40 ml) was added 8-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1,4-dioxa-spiro[4.5]dec-7-ene (1566 mg), dichloro(1,1′-bis(diphenylphosphino)ferrocene)palladium(II) DCM adduct (216 mg) and K2CO3 (2004 mg). The reaction was heated to about 90° C. overnight. The mixture was cooled, diluted with DCM and filtered through Celite. The filtrate was concentrated to dryness and the resulting residue was taken up in EtOAc (100 ml). The organics were washed with water, brine and concentrated to dryness. The crude product was purified by flash chromatography.
Intermediate 1c):
To intermediate 1b) (453 mg) in EtOH (20 ml) was added a slurry of 10% Pd/C in EtOH (20 ml). The mixture was stirred rapidly under H2 (1 atm) for about 2 h. The reaction mixture was filtered over a pad of Celite and washed with EtOAc (100 ml). The filtrate was concentrated to dryness to yield the final compound.
Intermediate 1d):
To the protected ketone from 1c) (407 mg) was added DCM (4 ml) and conc. HClO4 (0.4 ml), and the mixture was stirred at 45° C. for 4 h. The mixture was diluted with DCM and washed with saturated sodium bicarbonate solution, water and brine. The aqueous layers were extracted with DCM. The combined org. layers were dried over sodium sulfate, filtered and evaporated in vacuo. The residue was purified by column chromatography to yield the title compound.
Intermediate 1e):
The ketone from 1d) (3.880 g) was dissolved in anh. THF (25 ml) and cooled to −15° C. in ice/ethanol under Argon. To this, a solution of Tebbe reagent (0.5 M in Toluene, 25 ml) was added dropwise over 10 min. Stirring was continued in ice/ethanol for another 30 min. 100 ml of diethyl ether were added, and the reaction was slowly and carefully quenched by addition of saturated sodium bicarbonate solution (50 ml) while maintaining the temperature below 0° C. Methanol was added (40 ml), and the suspension stirred at RT for 60 min. The reaction mixture was filtered through Celite and the residue thorougly rinsed with EtOAc. The aqueous layer was separated, extracted with ethyl acetate (2×50 ml) and the combined organic phase was dried with magnesium sulfate and evaporated in vacuo. The crude product was purified by flash chromatography to yield the desired product as a solid.
Intermediate 1f:
To a solution of intermediate 1e) (800 mg), and (S)-2-(Boc-amino)-1-(4-chlorophenyl)but-3-ene (1690 mg) in anh. DCM (15 ml) was added Hoveyda-Grubbs 2nd generation catalyst (280 mg). The resulting dark green solution was then heated -under reflux in an Argon atmosphere for 48 h. An additional amount of catalyst was added (280 mg) and heating under Argon continued for 48 h more. The dark brown-green reaction mixture was then directly purified by flash chromatography.
Intermediate 1g):
To the Boc-protected amine from 1f) (143 mg) in DCM (5 ml) was added TFA (1 ml) and stirred at 0° C. for 90 min. The reaction mixture was diluted with DCM (10 ml) and carefully basified by pouring into 10% aqueous sodium carbonate solution (20 ml). The organic layer was separated and the aqueous layer was further extracted three times with DCM. The combined organics were washed with water and brine, dried over Na2SO4 and concentrated to give a white solid.
Intermediate 1h):
To (R)-Boc-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (24 mg) in DCM (2 ml) was added intermediate 1g) (37 mg), N-methylmorpholine (14 μl) and HOBt (14 mg) and it was stirred for 20 min. EDC (23 mg) was added and stirring was continued for 1 h. An additional amount of N-methylmorpholine (8 μl) was added and it was stirred overnight. The reaction mixture was poured into water (5 ml) and the organic phase was separated. The aqueous phase was extracted two times with DCM. The combined organic phases were washed with 0.1 N HCl and saturated sodium bicarbonate solution, dried over Na2SO4 and concentrated to yield the product which was purified by column chromatography.
The following examples can be prepared in a similar way:
off-white solid Rf=0.10 (EtOAc); Mp. 168-177° C.
To Boc-protected intermediate 9f) (27 mg) in DCM (1 ml) was added TFA (0.2 ml) and the mixture was stirred at 0° C. for 6 h. The reaction mixture was concentrated to dryness. The residue was dissolved in DCM and treated with diethyl ether. The precipitate was filtered off to yield the title compound as a solid.
The required intermediates can be synthesized in the following way:
Intermediate 9a):
1,4-Dioxa-8-azaspiro[4.5]decane (688 mg), intermediate 1a) (1004 mg), Pd2(dba)3 (235 mg), BINAP (442 mg) and cesium carbonate (3 g) were mixed together in toluene (20 ml). The mixture was degassed and heated to 100° C. for 3 d. The mixture was diluted with ether (100 ml) and filtered over Celite. The filtrate was concentrated and then subjected to chromatography on silica gel to yield the title compound.
Intermediate 9b):
To the protected ketone from 9a) (407 mg) was added DCM (4 ml) and conc. HClO4 (2 ml), and the mixture was stirred at 45° C. for 4 days. The mixture was diluted with DCM and washed with saturated sodium bicarbonate solution, water and brine. The aqueous layers were extracted with DCM. The combined org. layers were dried over sodium sulfate, filtered and evaporated in vacuo. The residue was purified by column chromatography to yield the title compound.
Intermediate 9c):
The ketone from 9b) (390 mg) was dissolved in anh. THF (5 ml) and cooled to −15° C. in ice/ethanol under Argon. To this, a solution of Tebbe reagent (0.5 M in Toluene, 2.5 ml) was added dropwise over 10 min. Stirring was continued in ice/ethanol for another 30 min. 10 ml of diethyl ether were added, and the reaction was slowly and carefully quenched by addition of saturated sodium bicarbonate solution (5 ml) while maintaining the temperature below 0° C. Methanol was added (4 ml), and the suspension stirred at RT for 60 min. The reaction mixture was filtered through Celite and the residue thorougly rinsed with EtOAc. The aqueous layer was separated, extracted with ethyl acetate (2×15 ml) and the combined organic phase was dried with magnesium sulfate and evaporated in vacuo. The crude product was purified by flash chromatography to yield the desired product as a solid.
Intermediate 9d):
To a solution of intermediate 9c) (79 mg), and (S)-2-(Boc-amino)-1-(4-chlorophenyl)but-3-ene (170 mg) in anh. DCM (3 ml) was added Hoveyda-Grubbs 2nd generation catalyst (26 mg). The resulting dark green solution was then heated under reflux in an Argon atmosphere for 48 h. An additional amount of catalyst was added (26 mg) and heating under Argon continued for 48 h more. The dark brown-green reaction mixture was then directly purified by flash chromatography.
Intermediate 9e):
To the Boc-protected amine from 9d) (154 mg) in DCM (5 ml) was added TFA (1 ml) and stirred at 0° C. for 90 min. The reaction mixture was diluted with DCM (10 ml) and carefully basified by pouring into 10% aqueous sodium carbonate solution (20 ml). The organic layer was separated and the aqueous layer was further extracted three times with DCM. The combined organics were washed with water and brine, dried over Na2SO4 and concentrated to give a white solid.
Intermediate 9f):
To (R)-Boc-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (24 mg) in DCM (2 ml) was added intermediate 9g) (37 mg), N-methylmorpholine (14 μl) and HOBt (14 mg) and it was stirred for 20 min. EDC (23 mg) was added and stirring was continued for 1 h. An additional amount of N-methylmorpholine. (8 μl) was added and stirred overnight. The reaction mixture was poured into water (5 ml) and the organic phase was separated. The aqueous phase was extracted two times with DCM. The combined organic phases were washed with 0.1 N HCl and saturated sodium bicarbonate solution, dried over Na2SO4 and concentrated to yield the product which was purified by column chromatography.
The following examples can be prepared in a similar way:
To chromone-2-carboxylic acid (16 mg) in DCM (2 ml) was added intermediate 1g) (35 mg), N-methylmorpholine (14 μl), HOBt (14 mg) and stirred for 20 min. EDC (23 mg) was added and stirring was continued for 1 h. An additional amount of N-methylmorpholine (8 μl) was added and stirred overnight. The reaction mixture was poured into water (5 ml) and the organic phase was separated. The aqueous phase was extracted two times with ethyl acetate. The combined organic phases were washed three times with 0.1 N HCl and three times with saturated sodium bicarbonate solution, dried over sodium sulfate and concentrated to yield the product which was purified by column chromatography.
white solid Rf=0.43 (EtOAc); Mp. 128-131° C.
The following examples can be prepared in a similar way:
white solid Rf=0.43 (EtOAc); Mp. 130-132° C.
white solid Rf=0.31 (EtOAc).
white solid Rf=0.38 (EtOAc).
White solid Rf=0.44 (EtOAc).
white solid Rf=0.26 (EtOAC).
white solid Rf=0.45 (EtOAc).
white solid Rf=0.45 (EtOAc).
White solid Rf=0.29 (EtOAc); Mp. 120-125° C.
white solid Rf=0.23 (EtOAc).
white solid Rf=0.18 (EtOAc).
white solid Rf=0.40 (EtOAc).
white solid Rf=0.34 (EtOAc).
white solid Rf=0.41 (EtOAc).
white solid Rf=0.43 (EtOAc).
white solid Rf=0.41 (EtOAc).
To chromone-2-carboxylic acid (16 mg) in DCM (2 ml) was added intermediate 9e) (35 mg), N-methylmorpholine (14 μl), HOBt (14 mg) and stirred for 20 min. EDC (23 mg) was added and stirring was continued for 1 h. An additional amount of N-methylmorpholine (8 μl) was added and stirred overnight. The reaction mixture was poured into water (5 ml) and the organic phase was separated. The aqueous phase was extracted two times with ethyl acetate. The combined organic phases were washed three times with 0.1 N HCl and three times with saturated sodium bicarbonate solution, dried over sodium sulfate and concentrated to yield the product which was purified by column chromatography.
The following examples can be prepared in a similar way:
off-white solid Rf=0.28 (EtOAc).
To a solution of example 34 (40 mg) in methanol (3 ml) was added Pd/C (5 mg). The solution was stirred under hydrogen (1 bar) overnight and filtered. The solvent was evaporated and the residue was purified by flash chromatography to yield the title compound.
white solid Rf=0.37 (EtOAc).
The following example can be prepared in a similar way:
white solid Rf=0.35 (EtOAc); Mp. 105-110° C.
Preparation of the chromone-2-carboxylic acids:
Chromone-2-carboxylic Acid 1
Intermediate CA1b) (5.85 g) was suspended in AcCl (110 ml) and concentrated sulfuric acid (4.40 ml) was added while stirring at RT. Then the slightly yellowish reaction mixture was heated to reflux with vigorous sirring and kept under reflux for 30 min. The reaction mixture was evaporated in vacuo to a volume of ca. 25 ml and then slowly and carefully added to well stirred H2O (300 ml) and stirring was continued for 1 h. After brief sonication, the formed precipitate was filtered off, washed with cold H2O (3×30 ml), and finally dried in vacuo at 40° C. overnight. The crude product was dissolved in a minimal amount of boiling H2O (270 ml) and left to slowly cool to RT. Crystallization was completed at RT for 6 h, then the crystalline product was filtered off and washed with cold H2O (3×10 ml). Finally the product was dried in vacuo at 40° C. overnight to yield the title compound.
Intermediate CA1a):
4-Trifluoromethoxyphenol (6.67 g) was dissolved in Et2O (55 ml) and TEA (6.36 ml) was added while stirring at RT. Then dimethyl acetylendicarboxylate (5.12 ml) was added with vigorous stirring and the reaction mixture stirred at RT in the dark overnight. The reaction mixture was diluted with Et2O (30 ml) and washed with 1 M HCl (3×65 ml), H2O (30 ml), and brine (25 ml), dried with Na2SO4 and then evaporated in vacuo. Finally it was dried under high vacuum for 2 h to yield the desired product.
Intermediate CA1b):
To intermediate CA1a) (9.57 g) was added a solution of NaOH (4.80 g) in water (45 ml) while stirring at RT. Then the reaction mixture was heated to reflux with vigorous stirring and kept under reflux for 3 h. The reaction mixture was extracted with Et2O (100 ml) and then acidified to below pH 1 with conc. HCl while cooling in ice/H2O. A white precipitate formed, which was filtered off, washed with H2O (3×30 ml), and finally it was dried in vacuo at 40° C. overnight to give the desired compound.
The following chromone-2-carboxylic acids were prepared using method 1: 6-ethylchromone-2-carboxylic acid, 6-isopropylchromone-2-carboxylic acid, 6-methoxychromone-2-carboxylic acid, 6-trifluoromethylchromone-2-carboxylic acid, 6-tert.-butylchromone-2-carboxylic acid, 6-chlorochromone-2-carboxylic acid, 6-trifluoromethoxychromone-2-carboxylic acid, 8-methoxychromone-2-carboxylic acid, 6-trifluoromethylsulfanylchromone-2-carboxylic acid, 8-chlorochromone-2-carboxylic acid, 8-fluorochromone-2-carboxylic acid 7-chlorochromone-2-carboxylic acid, 6-ethoxychromone-2-carboxylic acid, 6-methanesulfonylchromone-2-carboxylic acid, 8-oxo-8H-[1,3]dioxolo[4,5-g]chromene-6-carboxylic acid, 6-allyloxy-4-hydroxy-4H-chromene-2-carboxylic acid, 6-butoxy-4-hydroxy-4H-chromene-2-carboxylic acid, 6-propoxy-4-hydroxy-4H-chromene-2-carboxylic acid, 6-cyclopentyl-4-oxo-4H-chromene-2-carboxylic acid, 6-pentafluoroethoxy-4-oxo-4H-chromene-2-carboxylic acid, 4-oxo-6-[1,2,4]triazol-1-yl-4H-chromene-2-carboxylic acid, 6-imidazol-1-yl-4-oxo-4H-chromene-2-carboxylic acid, 6-acetylamino-4-oxo-4H-chromene-2-carboxylic acid, 6-(acetyl-methyl-amino)-4-oxo-4H-chromene-2-carboxylic acid, 6-methanesulfonylamino-4-oxo-4H-chromene-2-carboxylic acid, 6-(methanesulfonyl-methyl-amino)-4-oxo-4H-chromene-2-carboxylic acid and 6-dimethylamino-4-oxo-4H-chromene-2-carboxylic acid.
Chromone-2-carboxylic Acid 2:
Intermediate CA2a) (2.65 g) was suspended in sat. sodium bicarbonate solution (50 ml) and heated to 80° C. for 2 h. At the end of the reaction a clear solution was obtained. After cooling to room temperature the reaction mixture was acidified with HCl. The white precipitate was filtered off, washed with water and dried in vacuo at 40° C. overnight to give the title compound.
Intermediate CA2a):
Sodium (4.0 g) was added to dry methanol (50 ml). After the conversion to the methoxide was complete the solution was cooled and a solution of 2′-hydroxy-4′,5′-dimethoxyacetophenone (3.92 9) in diethyl oxalate (12 ml), methanol (50 ml) and toluene (50 ml) was added to it. The mixture was refluxed overnight. After cooling, diethyl ether (200 ml) was added. The sodium salt was filtered, washed with anhydrous ether, suspended in water and the solution acidified. The resultant precipitate was filtered and dried to yield a yellow solid.
The intermediate was dissolved in ethanol (100 ml) and heated at 100° C. for 15 min; concentrated HCl (2 ml) was added, and the solution stirred at 100° C. for 1.5 h. Immediately after addition of the acid a precipitate was formed. After cooling to room temperature the reaction mixture was diluted with water (150 ml) and the pale yellow precipitate was filtered off and washed with water. The product was dried under reduced pressure.
The following chromone-2-carboxylic acids were prepared using method 2: 6-methoxychromone-2-carboxylic acid, 7-methoxychromone-2-carboxylic acid, 6,7-dimethylchromone-2-carboxylic acid, 6,7-dimethoxychromone-2-carboxylic acid, 6-chlorochromone-2-carboxylic acid, 6,8-difluorochromone-2-carboxylic acid, 6,8-dichlorochromone-2-carboxylic acid and 7-fluorochromone-2-carboxylic acid.
Chromone-2-carboxylic Acid 3:
8-Methoxychromone-2-carboxylic acid (220 mg) was suspended in AcOH (2 ml) and conc. Hl (2 ml) was added while stirring at RT. Then the slightly yellowish suspension was heated to 120° C. with vigorous stirring and kept at this temperature for 60 min. The warm reaction mixture was slowly and carefully added to well stirred H2O (75 ml) and the resulting yellow solution was chilled in ice for 30 min. Crystallization was completed in the fridge for another 2 h. The formed crystalline precipitate was filtered off, washed with cold H2O (3×3 ml), and finally dried in vacuo at 40° C. overnight.
The following chromone-2-carboxylic acids were prepared using the demethylation method: 6-hydroxychromone-2-carboxylic acid, 7-hydroxychromone-2-carboxylic acid, 8-hydroxychromone-2-carboxylic acid, 6,7-dihydroxychromone-2-carboxylic acid and 6-hydroxy-7-methoxychromone-2-carboxylic acid.
A. Binding Assay
A membrane binding assay is used to identify competitive inhibitors of fluorescence labeled NDP-alpha-MSH binding to HEK293 cell membrane preparations expressing human melanocortin receptors.
The test compound or unlabeled NDP-alpha-MSH is dispensed at varying concentrations to a 384 well microtiter plate. Fluorescence labeled NDP-alpha-MSH is dispensed at a single concentration, followed by addition of membrane preparations. The plate is incubated for 5 h at room temperature.
The degree of fluorescence polarization is determined with a fluorescence polarization microplate reader.
B. Functional Assay
A functional cellular assay, based on competition between unlabeled cAMP and a fixed quantity of fluorescence labeled cAMP for a limited number of binding sites on a cAMP specific antibody, is used to discriminate melanocortin receptor agonists from antagonists by fluorescence polarization.
HEK293 cells expressing one of the human melanocortin receptors are transferred to 384 well microtiter plates, an appropriate amount of cAMP antibody is added, followed by the addition of different concentrations of the test compound to effect cAMP production. Cells are lysed and a fluorescence labeled cAMP conjugate is dispensed. The plate is read on a fluorescence polarization microplate reader and the amount of cAMP produced as a response to a test compound is compared to the production of cAMP resulting from stimulation with NDP-alpha-MSH.
To define antagonistic activity of a test compound, the compound is dispensed at different concentrations to cells stimulated by an appropriate amount of NDP-α-MSH. Inhibition of cAMP production is determined by comparing the inhibition of cAMP production of the test compound to the inhibition of cAMP production by a known inhibitor tested at the same concentrations.
Biological Data for Selected Examples of the Invention:
C. In Vivo Food Intake Models
1. Spontaneous Feeding Paradigm
Food intake in rats is measured after i.p. or p.o. administration of the test compound (see e.g. Chen, A. S. et al. Transgenic Res 2000 April; 9(2):145-54).
3-4 Hours following the onset of the light-phase, individually housed, male Wistar rats (200 -300 g) receive an ip injection or po application of test compound or vehicle in an administration volume of 2 ml/kg. Following the administration of substances (1-30 mg/kg), a pre-weighted amount of normal laboratory chow is placed into the food hopper. Food remaining is measured by hand at 1-2 hour intervals for up to 8 hours. Differences in food intake between test-compound and vehicle-treated rats are evaluated.
Selected Examples of the present invention were active in the rat model at 10 mg/kg after p.o. administration of the test compound using male Wistar rats (n=4-8).
Example 34 at 10 mg/kg lead to an increase in cumulative food intake of 3100% (2 hours following administration, p=0.048, n=4), 460% (4 hours following administration p=0.092, n=4),475% (6 hours following administration, p=0.018, n=4) and 151% (7 hours following admininistration, p=0.047, n=4), respectively, compared to control male Wistar rats receiving vehicle only (n=4).
2. Model of LPS and Tumor-Induced Cachexia
Prevention or amelioration of cachexia, induced by either lipopolysaccharide (LPS) administration or by tumor growth, is determined upon i.p. or p.o. administration of test compounds to rats (see e.g. Marks, D. L.; Ling, N and Cone, R. D. Cancer Res 2001 Feb 15;61(4):1432-8).
a) Lipopolysaccharide-Induced Cachexia in Rats (Acute Model)
1-2 Hours prior to the onset of the dark-phase, individually housed, male Wistar rats (200-300 g) receive an ip or po application of test-compound or vehicle (2 ml/kg, 1-30 mg/kg) which is followed or preceded by an ip injection of either lipopolysaccharide (LPS) or saline (2 ml/kg, 100 μg/kg). Food intake, water intake and body weight are measured at 1-24 hour intervals and differences between experimental groups are evaluated.
b) Tumour-Induced Cachexia in Mice (Chronic Model)
Subcutaneous injection of Lewis lung carcinoma cells to male C57BL6 mice (1 million cells/100 μl/mouse) results in non-metastasizing tumor growth which in turn results in loss of lean body mass. Chronic ip or po applications of test compounds (10 ml/kg, 1-30 mg/kg for 7-21 days) are accompanied by daily measurements of food intake, water intake and body weight. Lean body mass is measured at the start, during and at the termination of the study using magnetic resonance relaxometry, and at the end of the study using a conventional chemical extraction procedure (Soxhlet's extraction). Differences between experimental groups are evaluated.
D. Rat Ex Copula Assay
Sexually mature male Caesarian Derived Sprague Dawley (CD) rats (over 60 days old) are used with the suspensory ligament surgically removed to prevent retraction of the penis back into the penile sheath during the ex copula evaluations. Animals receive food and water ad lib and are kept on a normal light/dark cycle. Studies are conducted during the light cycle.
1. Conditioning to Supine Restraint for Ex Copula Reflex Tests
This conditioning takes approximately 4 days. Day 1, the animals are placed in a darkened restrainer and left for 15-30 minutes. Day 2, the animals are restrained in a supine position in the restrainer for 15-30 minutes. Day 3, the animals are restrained in the supine position with the penile sheath retracted for 15-30 minutes. Day 4, the animals are restrained in the supine position with the penile sheath retracted, until penile responses are observed. Some animals require additional days of conditioning before they are completely acclimated to the procedures; non-responders are removed from further evaluation. After any handling or evaluation, animals are given a treat to ensure positive reinforcement.
2. Ex Copula Reflex Tests
Rats are gently restrained in a supine position with their anterior torso placed inside a cylinder of adequate size to allow for normal head and paw grooming. For a 400-500 gram rat, the diameter of the cylinder is approximately 8 cm. The lower torso and hind limbs are restrained with a nonadhesive material (vetrap). An additional piece of vetrap with a hole in it, through which the glans penis will be passed, is fastened over the animal to maintain the preputial sheath in a retracted position. Penile responses will be observed, typically termed ex copula genital reflex tests. Typically, a series of penile erections will occur spontaneously within a few minutes after sheath retraction. The types of normal reflexogenic erectile responses include elongation, engorgement, cup and flip. An elongation is classified as an extension of the penile body. Engorgement is a dilation of the glans penis. A cup is defined as an intense erection where the distal margin of the glans penis momentarily flares open to form a cup. A flip is a dorsiflexion of the penile body.
Baseline and/or vehicle evaluations are conducted to determine how, and if, an animal will respond. Some animals have a long duration until the first response while others are non-responders altogether. During this baseline evaluation, latency to first response and number and type of responses are recorded. The testing time frame is 15 minutes after the first response.
After a minimum of 1 day between evaluations, these same animals are administered the test compound at 20 mg/kg and evaluated for penile reflexes. All evaluations are videotaped and scored later. Data are collected and analyzed using paired, 2 tailed t-tests to compared baseline and/or vehicle evaluations to drug treated evaluations for individual animals. Groups of a minimum of 4 animals are utilized to reduce variability.
Positive reference controls are included in each study to assure the validity of the study. Animals can be dosed by a number of routes of administration depending on the nature of the study to be performed. The routes of administration includes intravenous (IV), intraperitoneal (IP), subcutaneous (SC) and intracerebral ventricular (ICV).
E. Models of Female Sexual Dysfunction
Rodent assays relevant to female sexual receptivity include the behavioral model of lordosis and direct observations of copulatory activity. There is also a urethrogenital reflex model in anesthetized spinally transected rats for measuring orgasm in both male and female rats. These and other established animal models of female sexual dysfunction are described in. McKenna K E et al, A Model For The Study of Sexual Function In Anesthetized Male And Female Rats, Am. J. Physiol. (Regulatory Integrative Comp. Physiol 30): R1276-R1285, 1991; McKenna K E et al, Modulation By Peripheral Serotonin of The Threshold For Sexual Reflexes In Female Rats, Pharm. Bioch. Behav., 40:151-156,1991; and Takahashi L K et al, Dual Estradiol Action In The Diencephalon And The Regulation of Sociosexual Behavior In Female Golden Hamsters, Brain Res., 359:194-207,1985.
As a specific embodiment of an oral composition of a compound of the present invention, 20 mg of Example 18 is formulated with sufficient finely divided lactose to provide a total amount of 580 to 590 mg to fill a size 0 hard gelatin capsule.
As another specific embodiment of an oral composition of a compound of the present invention, 50 mg of Example 192 is formulated with sufficient finely divided lactose to provide a total amount of 580 to 590 mg to fill a size 0 hard gelatin capsule.
As another specific embodiment of an oral composition of a compound of the present invention, 30 mg of Example 34 is formulated with sufficient finely divided lactose to provide a total amount of 580 to 590 mg to fill a size 0 hard gelatin capsule.
While the invention has been described and illustrated in reference to certain preferred embodiments thereof, those skilled in the art will appreciate that various changes, modifications and substitutions, can be made therein without departing from the spirit and scope of the invention. For example, effective dosages other than the preferred doses as set out above, may be applicable as a consequence of the specific pharmacological responses observed and may vary depending upon the particular active compound selected, as well as from the type of formulation and mode of administration employed, and such expected variations or differences in the results are contemplated in accordance with the objects and practices of the present invention. It is intended, therefore, that the invention be limited only by the scope of the claims which follow and that such claims be interpreted as broadly as is reasonable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03006255.8 | Mar 2003 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP04/02909 | 3/19/2004 | WO | 9/11/2006 |
