Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
  • C07F9/02—Phosphorus compounds
  • C07F9/06—Phosphorus compounds without P—C bonds
  • C07F9/08—Esters of oxyacids of phosphorus
  • C07F9/09—Esters of phosphoric acids
  • C07F9/091—Esters of phosphoric acids with hydroxyalkyl compounds with further substituents on alkyl
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/08—Antiepileptics; Anticonvulsants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/28—Drugs for disorders of the nervous system for treating neurodegenerative disorders of the central nervous system, e.g. nootropic agents, cognition enhancers, drugs for treating Alzheimer's disease or other forms of dementia
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00

Definitions

• the present invention relates to pantetheine derivatives, their synthesis and medical uses thereof.
• Pantothenate kinase-associated neurodegeneration is a rare genetic neurodegenerative disease. The disease is caused by mutations in the gene coding for pantothenate kinase 2 (PANK2). Pantothenate kinase 2 phosphorylates pantothenate to 4'- phosphopantothenate in the de novo biosynthesis pathway of coenzyme A.
• PANK2 one of the four PANK iso forms known in humans and localized to the mitochondria
• PANK2 one of the four PANK iso forms known in humans and localized to the mitochondria
• Pantothenate, 4'-phosphopantothenate, pantetheine and 4'-phosphopantetheine have all been suggested as potential agents for the treatment of PKAN.
• 4'- phosphopantothenate and 4'-phosphopantetheine both intermediates of the Co A metabolic pathway downstream of the pantothenate kinase step, were envisioned as potential treatment options for PKAN (Zhou, B. et al. Nat. Genet., 2001, 28, 345, WO 2003/008626).
• Pantethine (the disulfide of pantetheine) has been shown to rescue a Drosophila model of PKAN (Rana, A. et al, PNAS, 2010, 107, 6988).
• acyloxyalkyl groups such as pivaloyloxymethyl (POM) and acetoxymethyl (AM). POM derivatives specifically have been shown to be stable in buffer and plasma.
• PKAN neurodegenerative diseases
• PKAN neurodegenerative diseases
• novel compounds useful for treating neurodegenerative diseases, such as PKAN which compounds are more effective in treating the disease.
• novel compounds useful for treating neurodegenerative diseases, such as PKAN which compounds have less side effects, e.g., show decreased toxicity, when treating the disease.
• novel compounds useful for treating neurodegenerative diseases, which compounds are more stable in human serum which compounds are more stable in human serum.
• novel medical uses of compounds derived from intermediates of the coenzyme-A biosynthetic pathway The present invention also relates to treatment methods using compounds of the invention, and to medicaments useful in treating neurodegenerative disorders, such as PKAN.
• the invention also relates to effective synthesis methods for compounds of the invention and compounds useful in treatment methods of the invention.
• the present invention relates to thioester derivatives of 4'- phosphopantetheine, such as (S)-acyl-4'-phosphopantetheines, i.e. , (S)-acyl-4'- phosphopantetheine derivatives, and their use for the treatment of neurodegenerative disorders, such as PKAN.
• 4'- phosphopantetheine such as (S)-acyl-4'-phosphopantetheines, i.e. , (S)-acyl-4'- phosphopantetheine derivatives
• the present invention also relates to synthesis methods of (S)-acyl-4'-phosphopantetheines and diverse other derivatives of 4'-phosphopantetheine.
• the present invention thus relates to a compound having the structural formula:
• R 2 and R3 are independently selected from the group consisting of: -methyl, -ethyl, -phenyl,
• R4 is -H or -alkyl, preferably -methyl
• R5 is -H or -alkyl, preferably C1-C4 alkyl, most preferably -methyl or t-butyl;
• Re is -H, -alkyl or -CH 2 (CO)OCH 3 ;
• R 7 is -H, -alkyl or -halogen
• Rs is -H, -alkyl, preferably t-butyl
• R9 is -H, -alkyl, preferably C1-C4 alkyl
• Rio is -H, -alkyl, preferably C1-C4 alkyl
• R11 and R12 are each independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy or halogen;
• Preferred alkyl groups in the above definitions are -methyl, -ethyl, -propyl, -butyl, preferably t-butyl.
• the D stereoisomer of Structure I is generally preferred.
• a straight line overlayed by a wavy line denotes the covalent bond of the respective residue to the Structure I.
• R 2 and R 3 are identical residues.
• Bis-POM and bis-AM structures are particularly preferred.
• Another aspect of the invention relates to a compound having the structural formula:
• R 2 and R3 are independently selected from the group consisting of: -H, -methyl, -ethyl, -
• R 2 and R3 jointly form a structure selected from the group consisting of
• R t is -H or -alkyl, preferably -methyl
• R5 is -H or -alkyl, preferably C 1 -C 4 alkyl, most preferably -methyl or t-butyl;
• Re is -H, -alkyl or -CH 2 (CO)OCH 3 ;
• R 7 is -H or -alkyl or -halogen
• Rs is -H or -alkyl, preferably t-butyl
• R9 is -H, -alkyl, preferably C 1 -C 4 alkyl
• Rio is -H, -alkyl, preferably C 1 -C 4 alkyl
• R 11 and Ri 2 are each independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy or halogen;
• R 2 and R 3 are both - ethyl or both -phenyl. In other preferred embodiments, R 2 is -ethyl and R 3 is -phenyl, or R 3 is -ethyl and R 2 is -phenyl.
• R 2 and R 3 are both
• R4 is -H, methyl; R5 is alkyl, such as methyl or t-butyl.
• R4 is -H and R 5 is -methyl.
• R 2 and R 3 may both be acetoxymethyl (AM).
• R4 is -H and R 5 is t-butyl.
• R 2 and R 3 may both be pivaloyloxymethyl (POM).
• R 2 and R 3 are both
• R 2 and R 3 are both
• Rg is -H, -alkyl or -CH 2 (CO)OCH 3 .
• the phosphate group forms a cyclic phosphate according to the following structure:
• R 7 is alkyl or halogen or the cyclic phosphate includes:
• R 8 is t-butyl
• R 2 and R 3 are both S-[(2-hydroxyethyl)sulfidyl]-2-thioethyl (DTE), or
• R 9 is alkyl, preferably -methyl, -ethyl, -propyl or -butyl, such as t-butyl.
• R 2 and R 3 are both S-acyl-2-thioethyl (SATE), or
• R 10 is alkyl, preferably -methyl, -ethyl, -propyl or -butyl, such as t-butyl
• Preferred alkyl groups are -methyl, -ethyl, -propyl, -butyl, preferably t-butyl.
• the D stereoisomer of Structure I is generally preferred.
• said medicament is useful in the treatment of a neurodegenerative disease, epilepsy or cancer; preferably a neurodegenerative disease or epilepsy; even more preferred a neurodegenerative disease.
• the neurodegenerative disease is pantothenate kinase-associated neurodegeneration (PKAN) .
• an aspect of the invention relates to a method of treating a neurodegenerative disease, epilepsy or cancer (preferably a neurodegenerative disease or epilepsy; even more preferred a neurodegenerative disease) by administering to a subject in need a therapeutically effective amount of a compound according to the invention as described hereinabove.
• the neurodegenerative disease is pantothenate kinase-associated neurodegeneration (PKAN).
• the present invention also relates to a method of producing a compound of the invention as described hereinabove, said method comprising the step of reacting 4'phosphopantothenate with an (S)-substituted mercaptoethylamine to yield (S)- substituted-4'-phosphopantetheine.
• the method includes enzymatic conversion of pantothenate to 4'- phosphopantothenate prior to the step of reacting 4'phosphopantothenate with an (S)- substituted mercaptoethylamine (e.g., (S)-trityl-mercaptoethylamine) to yield (S)- substituted-4 ' -phosphopantetheine (e.g., (S)-trityl-4 ' -phosphopantetheine) .
• an (S)- substituted mercaptoethylamine e.g., (S)-trityl-mercaptoethylamine
• S- substituted-4 ' -phosphopantetheine e.g., (S)-trityl-4 ' -phosphopantetheine
• the method further comprises converting (S)-substituted-4'- phosphopantetheine (e.g., (S)-trityl-4' -phosphopantetheine) to 4'-phosphopantetheine.
• (S)-substituted-4'- phosphopantetheine e.g., (S)-trityl-4' -phosphopantetheine
• the method further comprises converting 4 '-phosphopantetheine by thioesterification to (S)-acyl-4' -phosphopantetheine (e.g., to (S)-acetyl-4'- phosphopantetheine) .
• the method further comprises formation of a phosphate ester of said (S)-acyl-4'-phosphopantetheine with a chloromethyl ester or a iodomethyl ester of a carboxylic acid.
• the present invention also relates to a method of producing a compound of the invention as described hereinabove, said method comprising the steps of a) reacting pantothenate with an (S)-substituted mercaptoethylamine to yield (S)-substituted pantetheine, b) reacting the S-substituted pantetheine with a phosphorylating agent such as dibenzylchlorophosphate to obtain a phosphate ester of S-substituted 4'- phosphopantetheine such as S-trityl-4'-dibenzylphosphopantetheine and c) converting said phosphate ester of (S)-substituted-4'-phosphopantetheine (e.g., (S)-trityl-4'- dibenzylphosphopantetheine) to 4'-phosphopantetheine.
• a phosphorylating agent such as dibenzylchlorophosphate
• the (S)-substituent can be any of the thiol protecting groups, known in the literature, usually resulting in thioeter or thioester bond, e.g. trityl benzyl, benzoyl, stearoyl or palmitoyl group.
• the method further comprises converting 4'-phosphopantetheine by thioesterification to (S)-acyl-4'-phosphopantetheine (e.g., to (S)-acetyl-4'- phosphopantetheine).
• the method further comprises formation of a phosphate ester of said (S)-acyl-4'-phosphopantetheine with a chloromethyl ester or a iodomethyl ester of a carboxylic acid.
• the present invention relates to a method of producing a compound of the invention as described hereinabove, said method comprising the steps of reacting the (S)- substituted pantetheine such as (S)-acylpantetheine with a phosphorylating agent such as bis[(pivaloyloxy)methyl chlorophosphate to obtain a phosphate ester of S-substituted 4'- phosphopantetheine such as bis(pivaloyloxymethyl) ester of S-acyl-4'-phosphopantetheine.
• a phosphorylating agent such as bis[(pivaloyloxy)methyl chlorophosphate
• the (S)-substituent has a general formula wherein
• Figure 1 shows a chemoenzymatic route to (S)-acyl-4'-phosphopantetheine derivatives according to the invention.
• PANK pantothenate kinase; R 1 , R 3 , R 4 are not necessarily the same as Ri, R 3 , R4 as defined in the claims.
• Figure 2 shows improved stability of 4'-phosphopantetheine and (S)-acetyl-4'- phosphopantetheine in serum as compared to pantethine (Example 2).
• PBS phosphate buffered saline; FCS, fetal calf serum.
• Figure 3 shows that the rescue potential of 4'-phosphopantetheine and (S)-acetyl-4'- phosphopantetheine as compared to pantethine in a PKAN cell model (Example 3).
• (S)- acetyl-4'-phosphopantetheine is most effective.
• Figure 4 shows the rescue potential of pantethine, 4'-phosphopantetheine and (S)-acetyl- 4'-phosphopantetheine in cells treated with HOPAN (Example 4).
• (S)-acetyl-4'- phosphopantetheine is most effective.
• Figure 5 shows the rescue of 4'-phosphopantetheine and (S)-acetyl-4'-phosphopantetheine in Human PKAN cell model treated with HOPAN (Example 5).
• 4'-phosphopantetheine and (S)-acetyl-4'-phosphopantetheine are potent rescue molecules.
• Figure 6 shows a comparison of cellular toxicity of pantethine, 4'-phosphopantetheine and (S)-acetyl-4'-phosphopantetheine for human HEK293 cells (Example 6).
• Pantethine is more toxic compared to 4'-phosphopantetheine and (S)-acetyl-4'-phosphopantetheine.
• the term "neurodegenerative disease”, in accordance with the present invention, shall be interpreted as having the meaning commonly understood in the art.
• the "neurodegenerative disease” is selected from the group consisting of: Pantothenate kinase-associated neurodegeneration (PKAN), Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis (ALS), Dementia Ataxia telangiectasia, Autosomal dominant cerebellar ataxia, Batten disease, Corticobasal degeneration, Creutzfeldt-Jakob disease, Fatal familial insomnia, Hereditary motor and sensory neuropathy with proximal dominance, Infantile Refsum disease, JUNQ and IPOD, Locomotor ataxia, Lyme disease, Machado-Joseph disease, Mental retardation and microcephaly with pontine and cerebellar hypoplasia, Multiple system atrophy, Neuroacanthocytosis, Niemann-Pick disease, Pontocerebell
• Preferred neurodegenerative disorders in the context of the present invention are Pantothenate kinase-associated neurodegeneration (PKAN), Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis (ALS), Dementia; most preferably Pantothenate kinase-associated neurodegeneration (PKAN).
• PKAN Pantothenate kinase-associated neurodegeneration
• ALS Amyotrophic lateral sclerosis
• Dementia most preferably Pantothenate kinase-associated neurodegeneration (PKAN).
• alkyl refers to a straight or branched hydrocarbon chain radical consisting of carbon and hydrogen atoms, containing no saturation, having one to eight carbon atoms, and which is attached to the rest of the molecule by a single bond, e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl, etc.
• Alkyl radicals may be optionally substituted by one or more substituents such as a aryl, halo, hydroxy, alkoxy, carboxy, cyano, carbonyl, acyl, alkoxycarbonyl, amino, nitro, mercapto, alkylthio, etc. If substituted by aryl we have an "Aralkyl” radical, such as benzyl and phenethyl.
• Alkenyl refers to an alkyl radical having at least two carbon atoms covalently connected by a double bond.
• Cycloalkyl refers to a stable 3- to 10-membered monocyclic or bicyclic radical which is saturated or partially saturated, and which consist solely of carbon and hydrogen atoms, such as cyclohexyl or adamantyl. Unless otherwise defined, the term" cycloalkyl” is meant to include cycloalkyl radicals which are optionally substituted by one or more substituents such as alkyl, halo, hydroxy, amino, cyano, nitro, alkoxy, carboxy, alkoxycarbonyl.
• Aryl refers to single and multiple ring radicals, including multiple ring radicals that contain separate and/or fused aryl groups. Typical aryl groups contain from 1 to 3 separated or fused rings and from 6 to about 18 carbon ring atoms, such as phenyl, naphthyl, indenyl, fenanthryl or anthracyl radical.
• the aryl radical may be optionally substituted by one or more substituents such as hydroxy, mercapto, halo, alkyl, phenyl, alkoxy, haloalkyl, nitro, cyano, dialkylamino, aminoalkyl, acyl, alkoxycarbonyl, etc.
• Heterocyclyl refers to a stable 3-to 15 membered ring radical which consists of carbon atoms and from one to five heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur, preferably a 4-to 8-membered ring with one or more heteroatoms, more preferably a 5 -or 6-membered ring with one or more heteroatoms. It may be aromatic or not.
• the heterocycle may be a monocyclic, bicyclic or tricyclic ring system, which may include fused ring systems; and the nitrogen, carbon or sulfur atoms in the heterocyclyl radical may be optionally oxidised; the nitrogen atom may be optionally quaternized; and the heterocyclyl radical may be partially or fully saturated or aromatic.
• heterocycles include, but are not limited to, azepines, benzimidazole, benzothiazole, furan, isothiazole, imidazole, indole, piperidine, piperazine, purine, quinoline, thiadiazole, tetrahydro furan, coumarine, morpholine; pyrrole, pyrazole, oxazole, isoxazole, triazole, imidazole, etc.
• Alkoxy refers to a radical of the formula -ORa where Ra is an alkyl radical as defined above, e. g., methoxy, ethoxy, propoxy, etc.
• references herein to "substituted" groups in the compounds of the present invention refer to the specified moiety that is substituted at one or more available positions by one or more suitable groups, e. g., halogen such as fluoro, chloro, bromo and iodo, cyano, hydroxyl, nitro, azido, alkanoyl such as a CI -6 alkanoyl group such as acyl and the like, carboxamido, alkyl groups including those groups having 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms and more preferably 1-3 carbon atoms, alkenyl and alkynyl groups including groups having one or more unsaturated linkages and from 2 to about 12 carbon or from 2 to about 6 carbon atoms, alkoxy groups having one or more oxygen linkages and from 1 to about 12 carbon atoms or 1 to about 6 carbon atoms, aryloxy such as phenoxy, alkylthio groups including those moieties having one or more suitable
• pharmaceutically acceptable salts or solvates refers to any pharmaceutically acceptable salt, solvate, or any other compound which, upon administration to the recipient is capable of providing (directly or indirectly) a compound as described herein.
• non-pharmaceutically acceptable salts also fall within the scope of the invention since those may be useful in the preparation of pharmaceutically acceptable salts.
• the preparation of salts, prodrugs and derivatives can be carried out by methods known in the art. For instance, pharmaceutically acceptable salts of compounds provided herein are synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods.
• such salts are, for example, prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent or in a mixture of the two.
• nonaqueous media like ether, ethyl acetate, ethanol, isopropanol or acetonitrile are preferred.
• acid addition salts include mineral acid addition salts such as, for example, hydrochloride, hydrobromide, hydroiodide, sulphate, nitrate, phosphate, and organic acid addition salts such as, for example, acetate, maleate, fumarate, citrate, oxalate, succinate, tartrate, malate, mandelate, methanesulphonate and p-toluenesulphonate.
• mineral acid addition salts such as, for example, hydrochloride, hydrobromide, hydroiodide, sulphate, nitrate, phosphate
• organic acid addition salts such as, for example, acetate, maleate, fumarate, citrate, oxalate, succinate, tartrate, malate, mandelate, methanesulphonate and p-toluenesulphonate.
• alkali addition salts include inorganic salts such as, for example, sodium, potassium, calcium, ammonium, magnesium, aluminium and lithium salts, and organic alkali salts such as, for example, ethylenediamine, ethanolamine, N,N- dialkylenethanolamine, triethanolamine, glucamine and basic aminoacids salts.
• the present invention generally relates to the treatment of neurodegenerative diseases and compounds useful in such treatment.
• the neurodegenerative disease is pantothenate kinase-associated neurodegeneration (PKAN).
• PKAN is believed to be caused by impaired function of the enzyme pantothenate kinase 2.
• Pantothenate kinase is required for the synthesis of Coenzyme A (Rana, A. et al., PNAS, 2010, 107, 6988). It has been demonstrated in a fly model for PKAN, that the compound pantethine restores levels of Coenzyme A and thereby rescues all disease characteristics of PKAN (Rana, A. et al, PNAS, 2010, 107, 6988).
• pantethine to treat human subjects with pantethine is limited by the fact that pantethine is not stable in human serum and in human intestines and is rapidly converted into vitamin B5 and cysteamine (Wittwer etal, J Clin Invest, 1985, 76, 1665) and pantethine is toxic to wild type flies (Rana, A. et ah, PNAS, 2010, 107, 6988).
• the present invention overcomes this deficiency by providing treatment methods based on compounds which have improved stability in serum and which compounds are less toxic than pantethine.
• the present invention relates to a novel class of pharmaceuticals, for use in the treatment of neurodegenerative diseases (preferably PKAN), herein denoted as (S)- acyl-4'-phosphopantetheines.
• PKAN neurodegenerative diseases
• S neurodegenerative diseases
• the invention relates to prodrugs that liberate biologically active (S)- acyl-4'-phosphopantetheines in mammalian cells.
• prodrugs that liberate biologically active (S)- acyl-4'-phosphopantetheines in mammalian cells.
• the phosphate group is masked by moieties that facilitate the transfer of these compounds through cell membranes as well as the blood-brain-barrier.
• Such prodrugs have the following chemical structure:
• Ri is as defined in the appended claims, or Ri may be -CH 3 , -C 2 H 5 , -C 3 H 7 , -C 4 H 9 ; and R 2 and R 3 are as defined in the appended claims, or R 2 and R 3 may be -CH 2 0(CO)tBu, -CH 2 0(CO)Me.
• the D-isomer is preferred.
• Phosphate ester compounds are preferred due to their increased potential to penetrate membranes or, e.g., the blood-brain barrier.
• Suitable methods of producing such phosphate esters of S-acyl-phosphopantetheine are well known in the art.
• An exemplary synthetic method is provided in Example 7.
• a review of other suitable methods for forming prodrugs by esterification of phosphate groups of pharmaceutically active ingredients is provided by Schultz (2003, "Prodrugs of biologically active phosphate esters", Bioorg Med Chem 1 1 : 885), specific reference to which is hereby made, and the contents of which is incorporated herein by reference to the extent permitted.
• a third aspect of the invention relates to a novel and economically viable methods for the production of (S)-acyl-4 '-phosphopantetheine derivatives, as defined in the claims, including their prodrugs having a masked phosphate group.
• Masking of a phosphate group is preferably esterification of the phosphate group.
• the present invention is based on the observation that two novel pantethine-derivatives, namely 4'-phosphopantetheine and (S)-acetyl-4'-phosphopantetheine exhibit increased stability in human serum and are less toxic when compared to pantethine.
• (S)-acetyl-4'-phosphopantetheine is more effective than pantethine (and 4'-phosphopantetheine) in a drosophila disease model for PKAN.
• HDAC histone deacetylase
• (S)-acetyl-4'-phosphopantetheine is a compound that is rapidly converted into acetyl-CoA, thereby increasing protein acetylation.
• HDAC inhibitors specifically the valproic acid is currently used in diseases ranging from cancer, to epilepsy, to neurodegeneration.
• the disadvantage is that valproic acid has severe side effects.
• (S)-acetyl-4'- phosphopantetheine and its derivatives according to the invention can serve as an alternative for valproic acid in restoring or increasing protein acetylation without causing severe side effects.
• (S)-acetyl-4' -phosphopantetheine can serve as an alternative to valproic acid in various therapies. Therefore, (S)-acyl-4'- phosphopantetheine derivatives, such as (S)-acetyl-4' -phosphopantetheine derivatives, can be used in therapy for diseases in which valproic acid is currently used. Specific examples are: cancer, epilepsy, Alzheimer's disease.
• particularly preferred medical indications are neurodegenerative diseases as defined above, in particular PKAN, but also epilepsy, and cancer.
• derivatization of the phosphate group of (S)-acyl-4'- phosphopantetheines with acyloxyalkyl groups such as pivaloyloxymethyl (POM) and acetoxymethyl (AM) provides further advantageous properties, because such prodrug derivatives penetrate the blood-brain-barrier of mammals more easily. This is specifically important for the effective treatment of neurodegenerative diseases.
• the derivatization of the phosphate group is chemically easily achieved when using (S)- acyl-4 '-phosphopantetheines while, in contrast, such derivatization is much more difficult, if not impossible, to achieve in the case of 4'-phosphopantetheine. This is due to the interference of the free sulfhydryl group in the required chemical reactions.
• pantothenic acid is enzymatically converted to 4 '-phosphopantothenate.
• Isolated 4'-phosphopantothenic acid is then reacted with (S)-substituted mercaptoethylamines in the presence of a coupling reagent and an activator in a solvent.
• (S)-trityl-4'- phosphopantetheine obtained this way is isolated from the reaction mixture followed by its conversion to 4'-phosphopantetheine.
• 4 '-phosphopantetheine is converted to (S)- acyl-4 '-phosphopantetheine by thioesterification with the corresponding thioacid, such as thioacetic acid.
• pantothenic acid is reacted with previously prepared (S)-substituted mercaptoethylamines in the presence of a coupling reagent and an activator in a solvent.
• (S)-trityl-4' -pantetheine obtained this way is isolated from the reaction mixture, followed by its phosphorylation with dibenzylchlorophosphate in the presence of a base in a solvent. Removing of benzyl and trityl protecting group gives 4'-phosphopantetheine.
• 4'- phosphopantetheine is converted to (S)-acyl-4 '-phosphopantetheine by thioesterification with the corresponding thioacid, such as thioacetic acid.
• Masking the phosphate group includes the formation of phosphate esters from (S)-acyl-4'- phosphopantetheine with the corresponding chloro-methylester of the carboxylic acid, such as chloromethyl pivalate and chloromethyl acetate.
• masking of the phosphate group can be done by phosphorylating S- substituted pantetheine such as (S)-acetyl-4' -pantetheine with a suitable phosphorylatig agent such as bis[(pivaloyloxy)methyl chlorophosphate in the presence of a base in a solvent to obtain bis(pivaloyloxymethyl) ester of S-acyl-4'-phosphopantetheine
• S- substituted pantetheine such as (S)-acetyl-4' -pantetheine
• a suitable phosphorylatig agent such as bis[(pivaloyloxy)methyl chlorophosphate in the presence of a base in a solvent to obtain bis(pivaloyloxymethyl) ester of S-acyl-4'-phosphopantetheine
• the present invention further provides pharmaceutical compositions comprising a compound of invention, or a pharmaceutically acceptable salt thereof, preferably together with a pharmaceutically acceptable carrier, adjuvant, or vehicle, for administration to a patient.
• compositions of the invention include any solid (tablets, pills, capsules, granules etc.) or liquid (solutions, suspensions or emulsions) composition for oral, topical, parenteral or sublingual administration.
• the pharmaceutical compositions are in oral form, either solid or liquid.
• Suitable dose forms for oral administration may be tablets, capsules, syrups or solutions and may contain conventional excipients known in the art such as binding agents, for example syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrolidone; fillers, for example lactose, sugar, maize starch, calcium phosphate, sorbitol or glycine; tabletting lubricants, for example magnesium stearate; disintegrants, for example starch, polyvinylpyrrolidone, sodium starch glycollate or microcrystalline cellulose; or pharmaceutically acceptable wetting agents such as sodium lauryl sulfate.
• binding agents for example syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrolidone
• fillers for example lactose, sugar, maize starch, calcium phosphate, sorbitol or gly
• Administration of the compounds or compositions of the present invention may be by any suitable method, such as intravenous infusion, oral preparations, and intraperitoneal, intramuscular, sub-cutaneous, sublingual, topical and intravenous administration.
• Oral administration in particular sublingual administration is preferred because of the convenience for the patient and the chronic character of the diseases to be treated.
• the compounds and compositions of this invention may be used with other drugs to provide a combination therapy.
• the other drugs may form part of the same composition, or be provided as a separate composition for administration at the same time or at different time.
• a suitable dose for compounds of the invention is from 0.1 to 1000 mg/kg body weight/day, preferably 0.1 to 100 mg/kg body weight/day, more preferably 1 to 50 mg/kg body weight/day.
• Administration is preferably lx, 2x, 3x, or 4x per day, preferably lx or 2x per day.
• Pantothenic acid was enzymatically converted to 4'-phosphopantothenate. Isolated 4'- phosphopantothenic acid was then reacted with (S)-substituted mercaptoethylamines in the presence of a coupling reagent and an activator in a solvent. (S)-trityl-4'- phosphopantetheine obtained this way was isolated from the reaction mixture, followed by its conversion to 4 '-phosphopantetheme. Finally, 4 '-phosphopantetheme was converted to (S)-acyl-4' -phosphopantetheme by thioesterification with the corresponding thioacid, such as thioacetic acid.
• the phosphate group was masked by esterification, to improve the membrane penetration potential of the compound.
• Masking the phosphate group was effected by the formation of phosphate esters from (S)-acyl-4'- phosphopantetheine with the corresponding halomethyl ester of the carboxylic acid, such as chloromethyl pivalate, iodomethyl pivalate, chloromethyl acetate and iodomethyl acetate.
• Example 2 Increased stability of 4 '-phosphopantetheme and (S)-acetyl-4 '- phosphopantetheine in serum as compared to pantethine.
• This example shows the superior stability of (S)-acetyl-4 '-phosphopantetheme and 4'- phosphopantetheine in fetal calf serum (FCS) in comparison to pantethine.
• FCS fetal calf serum
• Pantethine has been shown to be rapidly converted in serum by pantetheinases to vitamin B5 and cysteamine (Wittwer et al, 1985, 76, 1665).
• Pantethine purchased from Sigma
• S S-acetyl-4'- phosphopantetheine and 4 '-phosphopantetheme were incubated at a final concentration of 1 mM in FCS and in PBS for 30 minutes at 37°C. After incubation, the samples were processed to remove proteins and HPLC analysis was used to assess the amount of remaining compound indicating the stability of the respective compounds.
• Pantethine is significantly degraded (60%), most likely by pantetheinase, whereas (S)-acetyl-4' -phosphopantetheme and 4 '-phosphopantetheme are stable and degrade by less than 10%.
• the Experiment was performed in triplicate, error bars indicate standard deviation in Figure 2.
• Example 3 Rescue potential of 4 '-phosphopantetheme and (S) -acetyl- 4 '- phosphopantetheine in cellular PKAN disease model
• dPANK/fbl PANK ortholog in Drosohila
• RNAi RNAi approach in Drosophila S2 cells
• a rescuing compound such as pantethine, 4 '-phosphopantetheme or (S)- acetyl-4 '-phosphopantetheme restores the cell survival.
• the following example is included to compare the rescue efficiency of pantethine, (S)-acetyl-4 '-phosphopantetheme and 4'- phosphopantetheme in such model system.
• Drosophila Schneider's S2 cells were cultured and subjected to RNAi treatment as described previously (Rana, A. et al, 2010, 107, 6988.). 100 ⁇ of pantethine, (S)-acetyl-4 '-phosphopantetheme and 4 '-phosphopantetheme was added to the cells and the rescue potential was assessed by determining the cell survival.
• Drosophila-S2 cells treated with the chemical inhibitor HOPAN (hopanthenate, CAS 17097-76-6, IUPAC: calcium 4-[[(2R)-2,4-dihydroxy-3,3- dimethylbutanoyl]amino]butanoate).
• HOPAN hopanthenate, CAS 17097-76-6, IUPAC: calcium 4-[[(2R)-2,4-dihydroxy-3,3- dimethylbutanoyl]amino]butanoate.
• HOPAN also serve as a model for PKAN.
• Cells treated with HOPAN also show a reduction in cell viability.
• the result is included to compare the rescue efficiency of pantethine, (S)-acetyl-4'- phosphopantetheine and 4'-phosphopantetheine in such model system.
• Drosophila Schneider's S2 cells were cultured and subjected to HOPAN (0.5mM) treatment with and without (S)-acetyl-4'-phosphopantetheine and 4'- phosphopantetheine for two days (Siudeja.K. et al, EMBO Mol Med. 2011, 3, 755). 100 ⁇ of (S)-acetyl-4'-phosphopantetheine and 4'-phosphopantetheine was compared for its rescue efficiency.
• the PKAN disease model can also be induced using HOPAN in mammalian cell lines.
• Rescue efficiency of (S)-acetyl-4'-phosphopantetheine and 4'-phosphopantetheine was studied in HOPAN induced PKAN model system, namely in mammalian HEK293 cells.
• HEK293 cells were cultured in vitamin B5 deficient DMEM (Thermo Scientific) supplemented with 10% dialysed FCS (Thermo Scientific) with and without HOPAN (0.5mM) and (S)-acetyl-4'-phosphopantetheine and 4'- phosphopantetheine for 4 days. ⁇ of (S)-acetyl-4'-phosphopantetheine and 4'- phosphopantetheine was compared for its rescue efficiency.
• Human HEK293 cells were treated with increasing concentrations of pantethine, 4'- phosphopantetheine and (S)-acetyl-4'-phosphopantetheine to determine and compare the toxicity of the compounds. A drop in cell counts indicates toxicity. Pantethine is inducing toxicity at lower concentrations compared to 4'-phosphopantetheine and (S)-acetyl-4'- phosphopantetheine, demonstrating that 4'-phosphopantetheine and (S)-acetyl-4'- phosphopantetheine are less toxic compared to pantethine. See Figure 6.
• Example 7 Preparation ofbis(pivaloyloxymethyl) ester of S-acyl-4 '-phosphopantetheine
• a phosphate-ester derivative according to the invention may be synthesized using the following procedure: Iodomethyl pivalate is freshly prepared by reaction of chloromethyl pivalate (0.151 g, 1 mmol) with sodium iodide (0.3 g, 2 mmol) in acetonitrile (1 mL) at 30°C for 5 h under N 2 atmosphere. To the reaction mixture is added dichloromethane (5 mL) and water (5 mL) and stirred. After phase separation the organic layer is washed with 2% aq.
• Phosphate-ester derivatives of the invention have improved bio-availability, due to their increased membrane permeation potential.
• Example 8 Alternative method for Preparation of bis(pivaloyloxymethyl) ester of S-acyl- 4 '-phosphopantetheine
• OPOM OPOM Tris(POM) phosphate (1 g, 2.3 mmol) was dissolved in piperidine (7 mL) and stirred at room temperature for 12 h. The solution was concentrated and further evaporated in vacuo until constant weight. (935 mg, 99.0% yield). The crude oil (935 mg, 2.28 mmol) was dissolved in water (20 ml) and treated with Dowex W50X2 H + form resin (19.2 g, 11,4 mmol, 0.6 mmol/g). The suspension was stirred at ambient temperature for 1 hour. The resin was filtered and washed with water.
• D-Pantothenic acid was prepared from its hemicalcium salt (Aldrich, > 99.0 %) reacting with oxalic acid.
• S-Tritylcysteamine was synthesized from cysteamine hydrochloride and trityl chloride as reported by Mandel et al. [A. L. Mandel, et al, Org. Lett. 2004, 6, 26, 4801-4803].
• Dibenzylchlorophosphate was prepared by reacting dibenzylphosphite with N-chlorosuccinimide as described by Itoh et al. [K. Itoh et al, Org. Lett. 2007, 9, 5, 879- 882] in toluene as a solvent.

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