THERAPEUTIC COMPOUNDS AND METHODS OF USE THEREOF

The invention provides a compound of formula (I): or a salt thereof, wherein A, B, R1, R2, R3 and X have any of the values described in the specification, as well as compositions comprising a compound of formula I. The compounds are useful as therapeutic agents for treating diastolic dysfunction.

BACKGROUND

Approximately half of the five million heart failure patients in the United States have preserved ejection fraction (HFpEF) (Owan T E, et al.N Engl J Med.2006, 355, 251). Diastolic dysfunction (DD), characterized by the reduced ability of the left ventricle to relax and fill with blood, underlies most HFpEF. At present, there are no specific treatments available for HFpEF (Jeong, E. M., et al.Circ J.2015, 79, 470).

Overproduction of harmful reactive oxygen species (ROS) from mitochondria can lead to oxidative stress in heart tissue and has been shown to contribute toward HFpEF (Silberman, G. A., et al.Circulation.2010, 121, 519; Jeong, E. M., et al.J Mol Cell Cardiol.2013, 56, 44; Jeong, E. M., et al.J Am Heart Assoc.2016, 5 and Liu, M., et al.JCI Insight.2019, 4). The ROS scavenger mitoTEMPO targets mitochondria to convert superoxide into hydrogen peroxide and has been shown to improve diastolic function in mice with HFpEF (Jeong, E. M., et al.J Am Heart Assoc.2016, 5).

Compounds of formula I have been synthesized and tested. Some of the compounds of formula I had higher potency than mitoTEMPO to scavenge mitochondrial ROS. Currently there is a need for agents that are useful for treatment of diastolic dysfunction.

SUMMARY

In one aspect the present invention provides compounds having a significant inhabitation of mitochondrial ROS that are useful for treatment of diastolic dysfunction.

Accordingly, the invention provides a compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein:

B is (C1-C10)alkyl optionally substituted with one or more groups independently selected from the group consisting of halo, —OH, —O—, —S—, nitro and cyano;

X is a suitable counter anion;

each Raand Rbis independently selected from the group consisting of H, aryl, heteroaryl, (C1-C6)alkyl and (C3-C6)cycloalkyl wherein any aryl, heteroaryl, (C1-C6)alkyl, and (C3-C6)cycloalkyl, is optionally substituted with one or more groups independently selected from the group consisting of halo, nitro, —OH, cyano; or Raand Rbtogether with the nitrogen to which they are attached form a 4-10 membered ring heterocycle.

The invention also provides a pharmaceutical composition comprising a compound of formula I or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.

The invention also provides a method for treating diastolic dysfunction in an animal (e.g., a mammal such as a human) comprising administering a compound of formula I or a pharmaceutically acceptable salt thereof to the animal.

The invention also provides a method for treating atrial fibrillation (e.g., diabetes induced atrial fibrillation) in an animal (e.g., a mammal such as a human) comprising administering a compound of formula I or a pharmaceutically acceptable salt thereof to the animal.

The invention also provides a compound of formula I or a pharmaceutically acceptable salt thereof for use in medical therapy.

The invention also provides a compound of formula I or a pharmaceutically acceptable salt thereof for the prophylactic or therapeutic treatment of diastolic dysfunction.

The invention also provides a compound of formula I or a pharmaceutically acceptable salt thereof for the prophylactic or therapeutic treatment of atrial fibrillation (e.g., diabetes induced atrial fibrillation).

The invention also provides the use of a compound of formula I or a pharmaceutically acceptable salt thereof to prepare a medicament for treating diastolic dysfunction in an animal (e.g. a mammal such as a human).

The invention also provides the use of a compound of formula I or a pharmaceutically acceptable salt thereof to prepare a medicament for treating atrial fibrillation (e.g., diabetes induced atrial fibrillation) in an animal (e.g. a mammal such as a human).

The invention also provides processes and intermediates disclosed herein that are useful for preparing a compound of formula I or a salt thereof.

DETAILED DESCRIPTION

The following definitions are used, unless otherwise described: halo or halogen is fluoro, chloro, bromo, or iodo. Alkyl, alkoxy, alkenyl, alkynyl, etc. denote both straight and branched groups; but reference to an individual radical such as propyl embraces only the straight chain radical, a branched chain isomer such as isopropyl being specifically referred to.

The term “alkyl”, by itself or as part of another substituent, means, unless otherwise stated, a straight or branched chain hydrocarbon radical, having the number of carbon atoms designated (i.e., C1-8means one to eight carbons). Examples include (C1-C5)alkyl, (C2-C5)alkyl, C1-C6)alkyl, (C2-C6)alkyl and (C3-C6)alkyl. Examples of alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, t-butyl, iso-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and and higher homologs and isomers.

The term “alkenyl” refers to an unsaturated alkyl radical having one or more double bonds. Examples of such unsaturated alkyl groups include vinyl, 2-propenyl, crotyl, 2-isopentenyl, 2-(butadienyl), 2,4-pentadienyl, 3-(1,4-pentadienyl) and the higher homologs and isomers.

The term “alkynyl” refers to an unsaturated alkyl radical having one or more triple bonds. Examples of such unsaturated alkyl groups ethynyl, 1- and 3-propynyl, 3-butynyl, and higher homologs and isomers.

The term “alkoxy” refers to an alkyl groups attached to the remainder of the molecule via an oxygen atom (“oxy”).

The term “alkylthio” refers to an alkyl groups attached to the remainder of the molecule via a thio group.

The term “cycloalkyl” refers to a saturated or partially unsaturated (non-aromatic) all carbon ring having 3 to 8 carbon atoms (i.e., (C3-C5)carbocycle). The term also includes multiple condensed, saturated all carbon ring systems (e.g., ring systems comprising 2, 3 or 4 carbocyclic rings). Accordingly, carbocycle includes multicyclic carbocyles such as a bicyclic carbocycles (e.g., bicyclic carbocycles having about 3 to 15 carbon atoms, about 6 to 15 carbon atoms, or 6 to 12 carbon atoms such as bicyclo[3.1.0]hexane and bicyclo[2.1.1]hexane), and polycyclic carbocycles (e.g tricyclic and tetracyclic carbocycles with up to about 20 carbon atoms). The rings of the multiple condensed ring system can be connected to each other via fused, spiro and bridged bonds when allowed by valency requirements. For example, multicyclic carbocyles can be connected to each other via a single carbon atom to form a spiro connection (e.g., spiropentane, spiro[4,5]decane, etc), via two adjacent carbon atoms to form a fused connection (e.g., carbocycles such as decahydronaphthalene, norsabinane, norcarane) or via two non-adjacent carbon atoms to form a bridged connection (e.g., norbornane, bicyclo[2.2.2]octane, etc). Non-limiting examples of cycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[2.2.1]heptane, pinane, and adamantane.

The term “aryl” as used herein refers to a single all carbon aromatic ring or a multiple condensed all carbon ring system wherein at least one of the rings is aromatic. For example, in certain embodiments, an aryl group has 6 to 20 carbon atoms, 6 to 14 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms. Aryl includes a phenyl radical. Aryl also includes multiple condensed carbon ring systems (e.g., ring systems comprising 2, 3 or 4 rings) having about 9 to 20 carbon atoms in which at least one ring is aromatic and wherein the other rings may be aromatic or not aromatic (i.e., cycloalkyl. The rings of the multiple condensed ring system can be connected to each other via fused, spiro and bridged bonds when allowed by valency requirements. It is to be understood that the point of attachment of a multiple condensed ring system, as defined above, can be at any position of the ring system including an aromatic or a carbocycle portion of the ring. Non-limiting examples of aryl groups include, but are not limited to, phenyl, indenyl, indanyl, naphthyl, 1, 2, 3, 4-tetrahydronaphthyl, anthracenyl, and the like.

The term “heterocycle” refers to a single saturated or partially unsaturated ring that has at least one atom other than carbon in the ring, wherein the atom is selected from the group consisting of oxygen, nitrogen and sulfur; the term also includes multiple condensed ring systems that have at least one such saturated or partially unsaturated ring, which multiple condensed ring systems are further described below. Thus, the term includes single saturated or partially unsaturated rings (e.g., 3, 4, 5, 6 or 7-membered rings) from about 1 to 6 carbon atoms and from about 1 to 3 heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur in the ring. The sulfur and nitrogen atoms may also be present in their oxidized forms. Exemplary heterocycles include but are not limited to azetidinyl, tetrahydrofuranyl and piperidinyl. The term “heterocycle” also includes multiple condensed ring systems (e.g., ring systems comprising 2, 3 or 4 rings) wherein a single heterocycle ring (as defined above) can be condensed with one or more groups selected from cycloalkyl, aryl, and heterocycle to form the multiple condensed ring system. The rings of the multiple condensed ring system can be connected to each other via fused, spiro and bridged bonds when allowed by valency requirements. It is to be understood that the individual rings of the multiple condensed ring system may be connected in any order relative to one another. It is also to be understood that the point of attachment of a multiple condensed ring system (as defined above for a heterocycle) can be at any position of the multiple condensed ring system including a heterocycle, aryl and carbocycle portion of the ring. In one embodiment the term heterocycle includes a 3-15 membered heterocycle. In one embodiment the term heterocycle includes a 3-10 membered heterocycle. In one embodiment the term heterocycle includes a 3-8 membered heterocycle. In one embodiment the term heterocycle includes a 3-7 membered heterocycle. In one embodiment the term heterocycle includes a 3-6 membered heterocycle. In one embodiment the term heterocycle includes a 4-6 membered heterocycle. In one embodiment the term heterocycle includes a 3-10 membered monocyclic or bicyclic heterocycle comprising 1 to 4 heteroatoms.

The term “heteroaryl” as used herein refers to a single aromatic ring that has at least one atom other than carbon in the ring, wherein the atom is selected from the group consisting of oxygen, nitrogen and sulfur; “heteroaryl” also includes multiple condensed ring systems that have at least one such aromatic ring, which multiple condensed ring systems are further described below. Thus, “heteroaryl” includes single aromatic rings of from about 1 to 6 carbon atoms and about 1-4 heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur. The sulfur and nitrogen atoms may also be present in an oxidized form provided the ring is aromatic. Exemplary heteroaryl ring systems include but are not limited to pyridyl, pyrimidinyl, oxazolyl or furyl. “Heteroaryl” also includes multiple condensed ring systems (e.g., ring systems comprising 2, 3 or 4 rings) wherein a heteroaryl group, as defined above, is condensed with one or more rings selected from cycloalkyl, aryl, heterocycle, and heteroaryl. It is to be understood that the point of attachment for a heteroaryl or heteroaryl multiple condensed ring system can be at any suitable atom of the heteroaryl or heteroaryl multiple condensed ring system including a carbon atom and a heteroatom (e.g., a nitrogen). Exemplary heteroaryls include but are not limited to pyridyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrazolyl, thienyl, indolyl, imidazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, furyl, oxadiazolyl, thiadiazolyl, quinolyl, isoquinolyl, benzothiazolyl, benzoxazolyl, indazolyl, quinoxalyl, and quinazolyl.

The term “alkoxycarbonyl” as used herein refers to a group (alkyl)-O—C(═O)—, wherein the term alkyl has the meaning defined herein.

The term “alkanoyloxy” as used herein refers to a group (alkyl)-C(═O)—O—, wherein the term alkyl has the meaning defined herein.

As used herein, the term “protecting group” refers to a substituent that is commonly employed to block or protect a particular functional group on a compound. For example, an “amino-protecting group” is a substituent attached to an amino group that blocks or protects the amino functionality in the compound. Suitable amino-protecting groups include acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBZ) and 9-fluorenylmethylenoxycarbonyl (Fmoc). Similarly, a “hydroxy-protecting group” refers to a substituent of a hydroxy group that blocks or protects the hydroxy functionality. Suitable protecting groups include acetyl and silyl. A “carboxy-protecting group” refers to a substituent of the carboxy group that blocks or protects the carboxy functionality. Common carboxy-protecting groups include phenylsulfonylethyl, cyanoethyl, 2-(trimethylsilyl)ethyl, 2-(trimethylsilyl)ethoxymethyl, 2-(p-toluenesulfonyl)ethyl, 2-(p-nitrophenylsulfenyl)ethyl, 2-(diphenylphosphino)-ethyl, nitroethyl and the like. For a general description of protecting groups and their use, see P. G. M. Wuts and T. W. Greene, Greene's Protective Groups in Organic Synthesis 4thedition, Wiley-Interscience, New York, 2006.

As used herein a wavy line “” that intersects a bond in a chemical structure indicates the point of attachment of the bond that the wavy bond intersects in the chemical structure to the remainder of a molecule.

The term “diastolic dysfunction” includes any condition wherein the ventricular chambers of the heart show evidence of impaired relaxation during the diastolic phase of the cardiac cycle. Such impaired relaxation can be evidenced by an increased slope of the end diastolic pressure-volume relationship, impaired movement of the cardiac tissue during diastole (commonly measured by echocardiography or cardiac magnetic resonance imaging), reduced early phase blood velocity across the mitral valve during diastole (E), reduced early phase mitral annular tissue velocity during diastole (e′), or a increase E/e′ ratio. Diastolic dysfunction is thought to underlie heart failure with perserved ejection fraction (HFpEF). HFpEF is the condition of heart failure wherein the ventricular systolic function is normal (i.e. when the cardiac left ventricular ejection fraction is greater than or equal to 50%). Major risk factors for this condition include aging, hypertension, diabetes mellitus, and female gender. Diastolic dysfunction often arises before heart failure symptoms and may be asymptomatic. Heart conditions wherein diastolic dysfunction can exist include HFpEF, hypertrophic cardiomyopathy, sarcoidosis, cardiac amyloidosis, and other infiltrative or inflammatory cardiac conditions.

The terms “treat”, “treatment”, or “treating” to the extent it relates to a disease or condition includes inhibiting the disease or condition eliminating the disease or condition, and/or relieving one or more symptoms of the disease or condition. The terms “treat”, “treatment”, or “treating” also refer to both therapeutic treatment and/or prophylactic treatment or preventative measures, wherein the object is to prevent or slow down (lessen) an undesired physiological change or disorder, such as, for example, the development or spread of cancer. For example, beneficial or desired clinical results include, but are not limited to, alleviation of symptoms, diminishment of extent of disease or disorder, stabilized (i.e., not worsening) state of disease or disorder, delay or slowing of disease progression, amelioration or palliation of the disease state or disorder, and remission (whether partial or total), whether detectable or undetectable. “Treat”, “treatment”, or “treating,” can also mean prolonging survival as compared to expected survival if not receiving treatment. Those in need of treatment include those already with the disease or disorder as well as those prone to have the disease or disorder or those in which the disease or disorder is to be prevented. In one embodiment “treat”, “treatment”, or “treating” does not include preventing or prevention,

The phrase “therapeutically effective amount” or “effective amount” includes but is not limited to an amount of a compound of the that (i) treats or prevents the particular disease, condition, or disorder, (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease, condition, or disorder, or (iii) prevents or delays the onset of one or more symptoms of the particular disease, condition, or disorder described herein.

The term “mammal” as used herein refers to humans, higher non-human primates, rodents, domestic, cows, horses, pigs, sheep, dogs and cats. In one embodiment, the mammal is a human. The term “patient” as used herein refers to any animal including mammals. In one embodiment, the patient is a mammalian patient. In one embodiment, the patient is a human patient.

The compounds disclosed herein can also exist as tautomeric isomers in certain cases. Although only one delocalized resonance structure may be depicted, all such forms are contemplated within the scope of the invention.

It is understood by one skilled in the art that this invention also includes any compound claimed that may be enriched at any or all atoms above naturally occurring isotopic ratios with one or more isotopes such as, but not limited to, deuterium (2H or D). As a non-limiting example, a —CH3group may be substituted with —CD3.

The pharmaceutical compositions of the invention can comprise one or more excipients. When used in combination with the pharmaceutical compositions of the invention the term “excipients” refers generally to an additional ingredient that is combined with the compound of formula (I) or the pharmaceutically acceptable salt thereof to provide a corresponding composition. For example, when used in combination with the pharmaceutical compositions of the invention the term “excipients” includes, but is not limited to: carriers, binders, disintegrating agents, lubricants, sweetening agents, flavoring agents, coatings, preservatives, and dyes.

When a bond in a compound formula herein is drawn in a non-stereochemical manner (e.g. flat), the atom to which the bond is attached includes all stereochemical possibilities. When a bond in a compound formula herein is drawn in a defined stereochemical manner (e.g. bold, bold-wedge, dashed or dashed-wedge), it is to be understood that the atom to which the stereochemical bond is attached is enriched in the absolute stereoisomer depicted unless otherwise noted. In one embodiment, the compound may be at least 51% the absolute stereoisomer depicted. In another embodiment, the compound may be at least 60% the absolute stereoisomer depicted. In another embodiment, the compound may be at least 80% the absolute stereoisomer depicted. In another embodiment, the compound may be at least 90% the absolute stereoisomer depicted. In another embodiment, the compound may be at least 95 the absolute stereoisomer depicted. In another embodiment, the compound may be at least 99% the absolute stereoisomer depicted.

Specific values listed below for radicals, substituents, and ranges, are for illustration only; they do not exclude other defined values or other values within defined ranges for the radicals and substituents. It is to be understood that two or more values may be combined. It is also to be understood that the values listed herein below (or subsets thereof) can be excluded.

In one embodiment, the invention provides, a compound of formula (I):

or a pharmaceutically acceptable salt thereof.

A specific value of A is —NRaC(═O)— wherein Rais independently selected from the group consisting of H, aryl, heteroaryl, (C1-C6)alkyl and (C3-C6)cycloalkyl wherein any aryl, heteroaryl, (C1-C6)alkyl, and (C3-C6)cycloalkyl, is optionally substituted with one or more groups independently selected from the group consisting of halo, nitro, —OH, cyano.

A specific value of A is —NHC(═O)—.

A specific value of B is (C1-C10)alkyl.

A specific value of B is methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl.

A specific value of X is halogen.

A specific value of X is Cl.

A specific value of X is Br.

A specific value of R1is phenyl.

A specific value of R2is phenyl.

A specific value of R3is phenyl.

In one embodiment, the compound or salt is administered intraperitoneally.

Processes for preparing compounds of formula I are provided as further embodiments of the invention and are illustrated by the following procedures in which the meanings of the generic radicals are as given above unless otherwise qualified.

In cases where compounds are sufficiently basic or acidic, a salt of a compound of formula I can be useful as an intermediate for isolating or purifying a compound of formula I. Additionally, administration of a compound of formula I as a pharmaceutically acceptable acid or base salt may be appropriate. Examples of pharmaceutically acceptable salts are organic acid addition salts formed with acids which form a physiological acceptable anion, for example, tosylate, methanesulfonate, acetate, citrate, malonate, tartarate, succinate, benzoate, ascorbate, α-ketoglutarate, and α-glycerophosphate. Suitable inorganic salts may also be formed, including hydrochloride, sulfate, nitrate, bicarbonate, and carbonate salts.

Sterile injectable solutions are prepared by incorporating the active compound in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filter sterilization. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and the freeze-drying techniques, which yield a powder of the active ingredient plus any additional desired ingredient present in the previously sterile-filtered solutions.

EXAMPLES

A solution of 4-amino-2,2,6,6-tetramethyl-1-piperidinyloxy, (2.5 g, 14.59 mM) and anhydrous Et3N (4.6 mL, 33 mM) in dry CHCl3(100 mL) was placed into a 250 ml round bottom flask and cooled to −10° C. Then 4-bromobutanoyl chloride (2.7 g, 14.55 mM) dissolved in dry CHCl3(10 mL) was added slowly dropwise at −10° C. The reaction solution was stirred for 1 h at 0° C. The resulting dark solution was washed with water (3×50 mL) and dried over sodium sulfate. The CHCl3was removed under reduced pressure and the residue was purified by silica gel chromatography (98:2 DCM, MeOH) to afford 2.6 g (56% yield) of 4-bromo-N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)butanamide as a light pinkish solid. This semi-pure product was carried forward to the next step with no further purification.

To 4-acetamino-(2′-chloro)-2,2,6,6-tetramethyl-1-piperidinyloxy (450 mg, 1.82 mM) dissolved in anhydrous acetonitrile (5 mL) was added tris(4-methoxyphenyl)phosphane (1.0 g, 2.83 mM). The reaction mixture was heated to 80° C. in a sealed tube under an inert atmosphere for 18 h. The solvent was removed under reduced pressure and then the residue was dissolved in a minimum amount of anhydrous acetone (3 to 5 mL). The solution was added to anhydrous diethyl ether (200 mL) dropwise, stirred for 5 minutes and filtered to afford the crude product, which was purified by silica gel column chromatography using (95:5%) dichloromethane and methanol. Then the compound was crystallized from toluene or precipitated (acetone and diethyl ether or DCM and diethyl ether) to afford the tri-4-methoxy compound as a light pink colored solid in 48% yield (525 mg). MP 172-174° C.1H NMR (400 MHz, CD2Cl2) δ 9.81 (d, J=7.4 Hz, 1H), 7.90-7.77 (m, 6H), 7.20-7.13 (m, 6H), 4.83 (s, 1H), 4.79 (s, 1H), 3.93 (s, 10H), 1.56-1.38 (m, 4H), 1.15 (s, 6H), 1.11 (s, 6H). MS (LCMS): C32H41N2O5P•+requires: 564.27 found 564.34.31P NMR δ 20.04.

Example 27. Compounds have been Tested for Mitochondrial Antioxidant Behavior and for Biological Activity Against Mitochondrial Oxidative Stress and Diastolic Dysfunction

To test compounds for mitochondrial antioxidant behavior, the ROS-Glo Assay to assess superoxide dismutase activity of induced mitochondrial reactive oxygen species (mitoROS). In this assay, menadione is used to induce mitoROS production, and then a fluorophore is used to measure the resultant hydrogen peroxide levels. A higher level of hydrogen peroxide means more dismutase activity. Data representative of ROS-Glo Assay are shown inFIGS.1,2,3,4and5.

To test compound activity against mitochondrial oxidative stress and diastolic dysfunction Mice were fed a high fat diet for 16 weeks starting at 6 weeks of age. Before treatment, fasting blood glucose (Gluc) and body weight were measured. Gluc was used to screen for diabetes mellitus (DM). Echocardiography was used to identify DD by measuring the E/e′ ratio. Treatment of compounds 58 and 94 was 1 mg/kg/day for 2 weeks. Then, E/e′ was reassessed. Data representative of this Assay are shown inFIGS.7,8and9.

Example 28. The Following Illustrate Representative Pharmaceutical Dosage Forms, Containing a Compound of Formula I (‘Compound X’), for Therapeutic or Prophylactic Use in Humans

The above formulations may be obtained by conventional procedures well known in the pharmaceutical art.