WO2011152721A1 - Derivatives of pantothenic acid and their use for the treatment of malaria - Google Patents

Abstract

The present invention concerns novel pantothenone compounds having pantetheinase inhibitory activity as well as antiplasmodial activity. These compounds can suitably be used in therapeutic and or prophylactic treatment of malaria. Furthermore, the present invention provides combinations of pantothenone compounds and pantothenamides. Combining a pantothenone with a pantothenamide increases the antimalarial potency by an order of magnitude. It is hypothesized that inhibition of pantetheinase activity could protect pantothenamides against degradation by serum-derived pantetheinases, thereby revealing the hitherto unknown antimalaria activity of pantothenamides. The present invention thus, for the first time, makes available compounds and combinations of compounds for use in therapeutic and or prophylactic treatment of malaria infection in a human or animal subject in need thereof, relying on interference with host or pathogen-derived pantetheinase dependent pathways.

Description

Field of the invention

The present invention concerns compounds and compositions having antimalarial activity as well as their use in the therapeutic and/or prophylactic treatment of humans and animals. More in particular the present invention provides novel pantothenone compounds inhibiting the activity of pantetheinase enzymes and having antimalarial activity. In addition, combinations of such compounds with antibiotic pantothenamide compounds, pharmaceutical compositions containing them, and uses thereof as medicinal products are provided.

Background

Malaria is one of the three major infectious diseases, reportedly causing about 500 million infections and more than one million deaths per year in the world, mainly in developing countries in tropics. The disease is spread by mosquito species infected with any of four kinds of pathogens (plasmodia) causing malaria in humans, notably P. falciparum, P. vivax, P. malariae and P. ovale, all belonging to the phylum Apicomplexa. As there is currently no effective vaccine against malaria, control of this disease relies strongly on antimalarial chemotherapy. Increasing reports of antibiotic resistance against current antimalarial agents have emphasized the critical need for the development of antimalaria compounds with novel modes of action. Nevertheless, since the discovery of chlroroquine in the late 40's of the previous century, only a few classes of new antimalarial drugs have been introduced (Eastman and Fidock, 2009, Nature Rev Microbiol 7:864-874).

Shortly after the discovery and introduction of penicillin before World War II, as an antibiotic against bacteria, a multitude of potential antibiotics against bacteria, fungi and protozoan parasites have been synthesized. Many of these compounds were derivatives of natural metabolites, including vitamins, intended to investigate their potential use as antimetabolites.

Derivatives of pantothenic acid (vitamin B5) have been synthesized and tested for their antibacterial, antifungal and antimalarial activity (reviewed in Spry et al, 2008, FEMS Microbiol Rev 32:56-106 and in Spry et al, 2010, Infect Disor Drug Targets 10:200-216). Coenzyme A (CoA), which is an essential cofactor for maintaining life, is synthesized from pantothenic acid, with the first step being the phosphorylation of pantothenate by pantothenate kinase. Cellular pantothenate is provided by nutritional intake via food and by recycling of CoA through hitherto unknown salvage pathways. CoA is used in a multitude of biochemical reactions (Leonarde et al, 2005, Progr Lipid Res 44: 125-153). It has been shown that pantothenate is an essential nutrient for Plasmodium falciparum, the major cause of malaria in humans, although the identity of pantothenate transporters and enzymes involved in CoA synthesis is uncertain (Spry et al, 2010, Infect Disor Drug Targets 10:200-216).

Chemical modifications of pantothenate, including pantoyl derivatives, pantothenamides and pantothenones have been shown to have antiplasmodial activity (nomenclature of the pantothenate derivatives adopted from Spry et al, 2008, FEMS Microbiol Rev 32:56-106). Pantoyl derivatives, like pantoyltauramide, were shown to be active in rodent malaria and avian malaria in vivo and caused a reduction of normal appearing P. falciparum parasites in vitro at 60 μΜ. Pantothenones (incuding D-phenylpantothenone and D-para-chlorophenylpantothenone) were shown to have weak antibacterial effects but showed significant antimalaria activity in vivo against P.gallinaceum in chickens. D-phenylpantothenone was also tested in vivo in humans at 2 gram per day against P.vivax. It was, however, found to be only slightly active, with a quinine equivalent of less than 0.1 (Berliner & Butler in Wiselogle, FY eds, 1946, A survey of antimalarial drugs 1941-1945, vol I, p 252 ). No activity against P. falciparum in vitro or in vivo has ever been reported.None of the aforementioned compounds have ever reached the stage of clinical development.

The discovery and application of new treatment options is still an absolute must in order to mitigate the development and/or consequences of increasing resistance among Plasmodium species. Furthermore, as most malaria patients live in developing countries, development of cheaper and more effective drugs is strongly demanded.

The present inventors have set out to develop new antimalarial compounds and compositions that could aid in achieving these and other objectives. Summary of the Invention

In view of these objectives, the present inventors designed and synthesized novel antimalarial compounds based on structural similarity to pantetheine, the presumed natural substrate of mammalian pantetheinases of the vanin gene family (Martin et al 2001, Immunogenetics 53:296-306). Pantetheine is the cysteamine amide analogue of pantothenic acid. The compounds of the invention have been found to inhibit growth of blood stages of the malaria parasite Plasmodium falciparum in vitro.

The present inventors have established that the pantothenone compounds of this invention possess both pantetheinase inhibitory activity and antimalarial activity. Without wishing to be bound by any particular theory, the present inventors hypothesize that the antibiotic activity against malaria parasites somehow involves inhibition of pantetheinases from host and/or parasite origin. The use of pantetheinase inhibitors for the treatment or prevention of malaria has not been suggested before.

As mentioned above, the pantothenones D-phenylpantothenone and D-para- chlorophenylpantothenone were found to be active against avian malaria parasites (reviewed in Spry et al, 2008, FEMS Microbiol Rev 32:56-106, and in Wiselogle, FY eds, 1946, A survey of antimalarial drugs 1941-1945, vol I). D-phenylpantothenone was found to be slightly active against P.vivax in humans, at high dosages of 2 gram per day. Since their original disclosure, in the forties, these compounds received no further attention in malaria research.

The pantothenone compounds of the present invention, which are structurally distinct from the pantothenones described above and all have proven anti-pantetheinase activity, show remarkably high potency against a relevant plasmodial strain of P. falciparum, e.g. with IC₅₀ values in the order of 1 μΜ and as much as 99% parasite growth inhibition at 10 μΜ. Furthermore, the pantothenone compounds of the present invention are well tolerated in rats and mice in dosages of up to 100 mg/kg without any signs of toxicity. The pantothenone compounds of the present invention have been shown to have very favourable pharmacodynamic characteristics such as prolonged total inhibition of plasma pantetheinase activity in rats, supportive of the feasibility of effective antimalaria treatment, including oral treatment.

The present inventors have also found that pantothenamide compounds have antiplasmodial activity in vitro. In the early 70 ^'s, amides derived from pantothenic acid (pantetheine analogues) had been reported to possess potent antibiotic activity in vitro (Clifton et al.1970, Arch Biochem Biophys 137: 523-528) against gram negative and gram positive bacteria in vitro. Hitherto, no experimental results of antimicrobial action of pantothenamides in animals or humans (in vivo) have ever been published. Furthermore, pantothenamides had never been reported to possess any antiplasmodial or antimalarial activity whatsoever.

Interestingly, the present inventors established that the use of these pantothenamides for antimalaria treatment is severely hampered by the fact that pantothenamides are degraded under physiological conditions in vivo, presumably by pantetheinases present in body fluids such as plasma.

Combining a pantothenone with a pantothenamide increases the pantothenone antimalarial potency by an order of magnitude, as demonstrated by the inventors in an assay that contained human serum. It is hypothesized that inhibition of pantetheinase activity could protect pantothenamides against degradation by serum-derived pantetheinases, thereby revealing the hitherto unknown antimalaria activity of pantothenamides. Alternatively, the pantothenamide may also potentiate the antimalarial effect of the pantothenone by a presently unknown mechanism. As will be illustrated in the appending examples, combining a pantothenone of the invention with a pantothenamide increases the antimalaria activity with a factor 10 as compared to the pantothenone alone and with a factor 200 as compared to the pantothenamide alone. To the best of the knowledge of the inventors, the concepts that pantothenamides may have antimalarial activity on their own, or may be used to potentiate the antimalarial activity of other pantothenate derivatives, including those that have pantetheinase inhibitory activity, has never been reported or suggested before.

The present invention thus, for the first time, makes available compounds and combinations of compounds for use in therapeutic and or prophylactic treatment of malaria infection in a human or animal subject in need thereof, relying on interference with host or pathogen-derived pantetheinase dependent pathways.

Detailed description of the invention

Hence, a first aspect of the invention concerns pantothenone compound selected from the group of substances represented by formula I or II, and pharmaceutically acceptable salts, esters, and prodrugs thereof:

wherein R¹, R² and R³ independently represent hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; R⁴ represents hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each of which may optionally be substituted with hydroxyl, thiol, halogen and/or cyanide;; X¹ and X² independently represent hydrogen, hydroxyl, thiol, cyanide, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, sulfonamide, amide, pyrazole or imidazole; X³ represents sulfur, oxygen, carbon or nitrogen, said nitrogen optionally being substituted by alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl; m is an integer within the range of 0-6, preferably m is an integer within the range of 0-6 excluding 0; and n is an integer within in the range of 0-6.

In a preferred embodiment, pantothenone compound selected from the group of substances represented by formula I or II, and pharmaceutically acceptable salts, esters, and prodrugs thereof are provided wherein R¹, R² and R³ independently represent hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; R⁴ represents a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each of which may optionally be substituted with hydroxyl, thiol, halogen and/or cyanide; X¹ and X² independently represent hydrogen, hydroxyl, thiol, cyanide, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, sulfonamide, amide, pyrazole or imidazole; X³ represents sulfur, oxygen or nitrogen, said nitrogen optionally being substituted by alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl; m is an integer within the range of 1-6; and n is an integer within in the range of 0-6.

The term 'pantothenone compound' is used herein to denote the class of compounds derived from pantothenic acid wherein the carboxyl group is replaced with a -(C=0)-R moiety. The compounds of formula (I) and (II) of the present invention all belong to the group of pantothenone compounds.

In a preferred embodiment of the invention pantothenone compounds are provided as defined above, wherein R³ represents hydrogen.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds are provided as defined above, wherein R¹ and R² are independently selected from the group of C₁-C4 alkyl.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds are provided as defined above, wherein R¹ and R² are methyl. Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds are provided as defined above, wherein X¹ and X² represent hydroxyl.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds are provided as defined above, wherein n is an integer within the range of 1-3, preferably 1.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds are provided as defined above, represented by formula (la):

wherein R⁴ represents an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; m is an integer within the range of 1-6; or a pharmaceutically acceptable salt, ester, amide, or prodrug thereof.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds of formulas (I) or (la) are provided as defined above, wherein R⁴ represents phenyl which may optionally be substituted with hydroxyl, thiol, halogen and/or cyanide;. Preferably, in said embodiment m is 1, 2 or 3 or 4, more preferably m is 1, 2 or 3, most preferably m is 1 or 3.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds of formulas (I) or (la) are provided as defined above, wherein m is 1 and R⁴ represents C₂-C4 alkenyl, preferably C3 alkenyl.

Particularly preferred pantothenone compounds according to this invention are selected from 'RR2', 'RR6', 'RR7' and 'RR8', preferably RR2 and RR6:

RH2

and pharmaceutically acceptable salts, esters, or prodrugs thereof.

In another embodiment the preferred pantothenone compound is selected from RR8, and pharmaceutically acceptable salts, esters, or prodrugs thereof.

In another embodiment of the invention, Pantothenone Compound according to claim 1, represented by formula Ila:

wherein:

R⁴ represents an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; X³ represents sulfur, oxygen or nitrogen, said nitrogen optionally being substituted by alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; m is an integer within the range of 1-6; or a pharmaceutically acceptable salt, ester, amide, or prodrug thereof. Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds of formulas (II) or (Ila) are provided as defined above, wherein R⁴ represents phenyl which may optionally be substituted with hydroxyl, thiol, halogen and/or cyanide;. Preferably, in said embodiment m is 1, 2, 3, 4 or 5, more preferably m is 2, 3 or 4, most preferably m is 2 or 3.

Furthermore, in a particularly preferred embodiment of the invention pantothenone compounds of formulas (II) or (Ila) are provided as defined above, wherein m is 1 and R⁴ represents C2-C4 alkenyl, preferably C3 alkenyl.

A second aspect of the invention concerns antimalarial compositions comprising a combination of a pantothenone compound, preferably a pantothenone compound as defined in any of the foregoing, and a pantothenamide compound.

The term 'pantothenamide compound' is used herein to denote the class of compounds derived from pantothenic acid wherein the carboxyl group is replaced with a -(C=0)-NRR' moiety, as will be understood by those skilled in the art.

In one embodiment, said pantothenamide compound is selected from the group represented by formula (III):

wherein R⁵ represents hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; R⁶ and R⁷ independently represent hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; X⁴ and X⁵ independently represent hydrogen or a group selected from hydroxyl, thiol, cyanide, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, sulfonamide, amide, pyrazole or imidazole; X⁶ represents hydrogen, hydroxyl, halogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; and pharmaceutically acceptable salts, esters, and prodrugs thereof; preferably X⁶ represents hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; and pharmaceutically acceptable salts, esters, and prodrugs thereof.

In an embodiment of the invention the pantothenamide compound is selected from the group of is selected from the group represented by formula (Ilia):

and pharmaceutically acceptable salts, esters, and prodrugs thereof.

Furthermore, in a preferred embodiment of the invention, the pantothenamide compound is selected from the group represented by formula (Illb):

wherein R⁵ represents a group selected from alkyl, alkenyl or alkynyl; and pharmaceutically acceptable salts, esters, and prodrugs thereof.

Pharmaceutical composition according to any one of claims 16-18, wherein the pantothenamide compound is selected from N5Pan, N7Pan and N9Pan, preferably N5Pan and N7Pan:

and pharmaceutically acceptable salts, esters, and prodrugs thereof.

A particularly preferred embodiment of the invention concerns a composition as defined herein before, comprising a combination of a pantothenone selected from RR2, RR6, RR7 and RR8 and a pantothenamide selected from N5Pan, N7Pan and N5Pan. In a particularly preferred embodiment of the invention, a composition is provided comprising a combination of a pantothenone and a pantothenamide selected from a) RR2 and N5Pan; b) RR2 and N7Pan; c) RR2 and N9Pan; d) RR6 and N5Pan; e) RR6 and N7Pan; f) RR6 and N9Pan g) RR7 and N5Pan; h) RR7 and N7Pan; i) RR7 and N9Pan; j) RR8 and N5Pan; k) RR8 and N7Pan and 1) RR8 and N9Pan. As will be understood by those skilled in the art, embodiment wherein compositions contain pharmaceutically acceptable salts, esters and prodrugs of the recited pantothenones and/or pantothenamides are also encompassed by the invention. An embodiment provides a combination of N5Pan and RR2; a combination of N7Pan and RR2; a combination of N5Pan, N7Pan and RR2; a combination of N5Pan and RR6; a combination of N7Pan and RR6; or a combination of N5Pan, N7Pan and RR6; or pharmaceutically acceptable salts, esters, or prodrugs of said compounds

As utilized herein, the term "alkyl", either alone or within other terms, means an acyclic alkyl radical, preferably containing from 1 to 10, more preferably from 1 to about 8 carbon atoms and most preferably 1 to about 6 carbon atoms. Said alkyl radicals may be optionally substituted as defined elsewhere in this document. Examples of such radicals include methyl, ethyl, chloroethyl, hydroxyethyl, n-propyl, oxopropyl, isopropyl, n-butyl, cyanobutyl, isobutyl, sec-butyl, tert-butyl, pentyl, aminopentyl, iso-amyl, hexyl, octyl and the like.

The term "alkenyl" refers to an unsaturated, acyclic hydrocarbon radical in so much as it contains at least one double bond. Such alkenyl radicals typically contain from 2 to 10 carbon atoms, preferably from 2 to 8 carbon atoms and most preferably 2 to about 6 carbon atoms. Said alkenyl radicals may be optionally substituted as defined elsewhere in this document. Examples of suitable alkenyl radicals include ethenyl, 1-propenyl, 2-propenyl, 2- methyl-l-propenyl, 1-butenyl, 2-butenyl and the like. The term "alkynyl" refers to an unsaturated, acyclic hydrocarbon radical in so much as it contains one or more triple bonds, such radicals typically containing from 2 to 10 carbon atoms, preferably having from 2 to 8 carbon atoms and most preferably from 2 to 6 carbon atoms. Said alkynyl radicals may be optionally substituted with groups as elsewhere in this document. Examples of suitable alkynyl radicals include ethynyl, propynyl, hydroxypropynyl, butyne-l-yl, butyn-2-yl, pentyne-l-yl, pentyne-2-yl, 4 methoxypentyn-2-yl, 3-methylbutyn-l- yl, hexyne-l-yl, hexyne-2-yl, hexyne-3-yl, 3,3-dimethylbutyn-l-yl radicals and the like.

The term "cycloalkyl" refers to carbocyclic radicals typically having 3 to 10 carbon atoms, preferably 3 to 8 carbon atoms, most preferably 5 to 8 carbon atoms. Said cycloalkyl radicals may be optionally substituted as defined elsewhere in this document. Examples of suitable cycloalkyl radicals include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.

The term "cycloalkenyl" embraces carbocyclic radicals having 3 to 10 carbon atoms and one or more carbon-carbon double bonds. Preferred cycloalkenyl radicals are "lower cycloalkenyl" radicals having 3-8 carbon atoms, more preferably 5-8. Examples include radicals such as cyclobutenyl, cyclopentenyl, cyclohexenyl and cycloheptenyl.

The term "aryl", alone or in combination, means a 5-10 membered carbocyclic aromatic system containing one, two or three rings wherein such rings may be attached together in a pendant manner or may be fused. The term "fused" means that a second ring is present having two adjacent atoms in common with the first ring. The term "fused" is equivalent to the term "condensed". The term "aryl" embraces aromatic radicals such as phenyl, naphthyl, tetrahydronaphthyl, indane and biphenyl.

The term "heteroaryl" (on its own or in any combination, such as "heteroaryloxy", or "heteroaryl alkyl") is used herein to mean a 5-10 membered aromatic ring system containing one, two or three rings, which may be attached in a pendant manner or may be fused, wherein at least one of said rings contains one or more heteroatoms selected from the group consisting of N, O or S. Examples include, but are not limited to, pyrrole, pyrazole, furan, thiophene, quinoline, isoquinoline, quinazolinyl, pyridine, pyrimidine, oxazole, thiazole, thiadiazole, tetrazole, triazole, imidazole, or benzimidazole.

The terms "cycloalkylalkyl", "cycloalkenylalkyl", "arylalkyl" and "heteroarylalkyl" embrace, respectively, the afore-defined cycloalkyl, cycloalkenyl, aryl and heteroaryl radicals attached to the main molecular moiety, i.e. the basic moiety depicted in the formulae, through an alkyl radical, typically an alkyl radical having 1-10, preferably 1-8, most preferably 1-6 carbon atoms, as will be understood by those skilled in the art. Representative examples of arylalkyl include, but not limited to, phenylmethyl, phenylethyl and naphthylmethyl. Representative examples of heteroarylalkyl groups include, but are not limited to, thiazolylmethyl, thienylmethyl, furylmethyl, imidazolylmethyl and pyridylmethyl.

The term "sulfonamide" includes moieties which contain a group of the formula - SO₂NRR, where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein.

The term "amide" includes moieties which contain a nitrogen atom which is bound to the carbon of a carbonyl or a thiocarbonyl group. The term includes "alkaminocarboxy" groups which include alkyl, alkenyl, or alkynyl groups bound to an amino group bound to a carboxy group. It includes arylaminocarboxy groups which include aryl or heteroaryl moieties bound to an amino group which is bound to the carbon of a carbonyl or thiocarbonyl group. The terms "alkylamino carboxy," "alkenylaminocarboxy," "alkynylaminocarboxy," and "arylaminocarboxy" include moieties wherein alkyl, alkenyl, alkynyl and aryl moieties, respectively, are bound to a nitrogen atom which is in turn bound to the carbon of a carbonyl group.

The compounds of the invention can contain one or more chiral centers and/or double bonds and, therefore, exist as stereoisomers, such as double-bond isomers (i.e., geometric isomers), enantiomers, or diastereomers. According to the invention, the chemical structures depicted herein, and therefore the compounds of the invention, encompass all of the corresponding compound's enantiomers and stereoisomers, that is, both the stereomerically pure form (e.g., geometrically pure, enantiomerically pure, or diastereomerically pure) and enantiomeric and stereoisomeric mixtures.

A compound of the invention is considered optically active or enantiomerically pure (i.e., substantially the R-form or substantially the S-form) with respect to a chiral center when the compound is about 90% enantiomeric excess (ee) or greater, preferably, equal to or greater than 95% enantiomeric excess with respect to a particular chiral center. A compound of the invention is considered to be in enantiomerically-enriched form when the compound has an enantiomeric excess of greater than about 1% ee, preferably greater than about 5% ee, more preferably, greater than about 10% ee with respect to a particular chiral center. A compound of the invention is considered diastereomerically pure with respect to multiple chiral centers when the compound is about 90%> de (diastereomeric excess) or greater, preferably, equal to or greater than 95% de with respect to a particular chiral center. A compound of the invention is considered to be in diastereomerically-enriched form when the compound has an diastereomeric excess of greater than about 1% de, preferably greater than about 5% de, more preferably, greater than about 10% de with respect to a particular chiral center. As used herein, a racemic mixture means about 50% of one enantiomer and about 50% of is corresponding enantiomer relative to all chiral centers in the molecule. Thus, the invention encompasses all enantiomerically-pure, enantiomerically-enriched, diastereomerically pure, diastereomerically enriched, and racemic mixtures of compounds of Formulas I through III.

Enantiomeric and diastereomeric mixtures can be resolved into their component enantiomers or stereoisomers by well known methods, such as chiral-phase gas chromatography, chiral-phase high performance liquid chromatography, crystallizing the compound as a chiral salt complex, or crystallizing the compound in a chiral solvent. Enantiomers and diastereomers can also be obtained from diastereomerically- or enantiomerically-pure intermediates, reagents, and catalysts by well known asymmetric synthetic methods.

In a particularly preferred embodiment of the invention, the pantothenic acid and/or pantothenamide derivatives or analogues are 'enantiomerically pure' (i.e. according to the above definitions) derivatives or analogues of D(+) pantothenic acid and/or D(+) pantothenamide, i.e. 'enantiomerically pure' substances possessing the same stereochemical arrangement as the corresponding stereocenter in D-(+) pantothenic acid and/or D(+) pantothenamide.

The compounds and cobinations may be used pharmaceutically in the form of the free base, in the form of salts, solvates and as hydrates. All forms are within the scope of the invention. The term "pharmaceutically acceptable salts, esters, and prodrugs" as used herein refers to salts, amino acid addition salts, esters, and prodrugs of the compounds of the present invention which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of patients without undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio, and effective for their intended use, as well as the zwitterionic forms, where possible, of the compounds of the invention.

The term "salts" refers to inorganic and organic acid or base addition salts of compounds of the present invention. These salts can be prepared in situ during the final isolation and purification of the compounds or by separately reacting the purified compound in its free base form with a suitable organic or inorganic acid and isolating the salt thus formed. Depending on the particular substituents found on the compounds described herein. When compounds of the present invention contain relatively acidic functionalities, base addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired base, either neat or in a suitable inert solvent. Examples of pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amino, or magnesium salt, or a similar salt. When compounds of the present invention contain relatively basic functionalities, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired acid, either neat or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include those derived from inorganic acids like hydrochloric, hydrobromic, nitric, carbonic, monohydrogencarbonic, phosphoric, monohydrogenphosphoric, dihydrogenphosphoric, sulfuric, monohydrogensulfuric, hydriodic, or phosphorous acids and the like, as well as the salts derived from relatively nontoxic organic acids like acetic, propionic, isobutyric, maleic, malonic, benzoic, succinic, suberic, fumaric, lactic, mandelic, phthalic, benzenesulfonic, p-tolylsulfonic, citric, tartaric, methanesulfonic, and the like. Also included are salts of amino acids such as arginate and the like, and salts of organic acids like glucuronic or galactunoric acids and the like (see, for example, Berge et al, "Pharmaceutical Salts", Journal of Pharmaceutical Science, 1977, 66, 1-19). Acid and basic addition salts may be formed with the compounds of the invention for use as sources of the free base form even if the particular salt per se is desired only as an intermediate product as, for example, when the salt is formed only for the purposes of purification and identification.

Examples of suitable esters include compounds of the invention which hydrolyze in vivo and include those that break down readily in the human body to leave the parent compound or a salt thereof. Examples of pharmaceutically acceptable, relatively non-toxic esters of the invention include Ci-C₆ alkyl esters and C5-C7 cycloalkyl esters. Esters of the compounds of the invention can be prepared according to conventional methods. Pharmaceutically acceptable esters can be obtained through reaction of hydroxy groups of the compound with an organic acid, such as acetic acid or benzoic acid. In the case of compounds containing carboxylic acid groups, the pharmaceutically acceptable esters are prepared by reaction of said carboxylic acid group, as will be understood by those skilled in the art.

The term "prodrug" refers to compounds that are rapidly transformed in vivo to yield the parent compounds of the above formula, for example, by hydrolysis in blood. A thorough discussion is provided in T. Higuchi and V. Stella, "Pro-drugs as Novel Delivery Systems," Vol. 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche, American Pharmaceutical Association and Pergamon Press, 1987, both of which are incorporated herein by reference. Furthermore, the compounds of the present invention can exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like. In general, the solvated forms are considered equivalent to the unsolvated forms for the purposes of the present invention.

The compounds of the invention can be provided as crystalline or amorphous products. They may be obtained, for example, as solid plugs, powders, or films by methods such as precipitation, crystallization, freeze drying, spray drying, or evaporative drying. Microwave or radio frequency drying may be used for this purpose.

Another aspect of the present invention concerns the use of the compounds of the invention, the combinations thereof or the pharmaceutical compositions containing them, as defined herein before, as a medicament, typically for use in a therapeutic or prophylactic method of treatment, in particular a method of treatment of a disease or condition selected from malaria and/or infection by a protistan parasite of the genus Plasmodium, in a human subject in need thereof. In a particularly preferred embodiment said disease or condition is selected from malaria and/or infection by P. falciparum, P. vivax, P. malariae and/or P. ovale.

Another aspect of the present invention, a method of treating and/or preventing a disease or condition selected from the group of malaria and/or infection by a protistan parasite of the genus Plasmodium, in a human subject in need thereof, said method comprising administering to said subject an effective amount of a pantothenone compound, a combination of a pantothenone compound and a pantothenamide or pharmacuetical composition as defined in any one of the foregoing.

In a preferred embodiment of the invention, these uses and methods concern treatment of human subjects in need thereof, especially a subject infected by or at risk of becoming infected by a protistan parasite of the genus Plasmodium, especially P. falciparum, P. virax, P. ovale or P. malariae.

As used herein, and as well understood in the art, "treatment" is an approach for obtaining beneficial or desired results, including clinical results. Beneficial or desired clinical results can include, but are not limited to, alleviation or amelioration of one or more symptoms or conditions, diminishment of extent of disease, stabilized (i.e. not worsening) state of disease, preventing spread of disease, delay or slowing of disease progression, amelioration or palliation of the disease state, and remission. "Treatment" can also mean prolonging survival as compared to expected survival if not receiving treatment. The term "prevention" or "prophylaxis", or synonym thereto, as used herein refers to a reduction in the risk or probability of a patient becoming afflicted with malaria or manifesting a symptom associated with malaria.

The term a "therapeutically effective amount", "effective amount" or a "sufficient amount" of a compound of the present invention is a quantity sufficient to, when administered to the subject, including a mammal, for example a human, effect beneficial or desired results, including clinical results, and, as such, an "effective amount" or synonym thereto depends upon the context in which it is being applied. In the context of disease, therapeutically effective amounts of the compounds of the present invention are used to treat, modulate, attenuate, reverse, or effect malaria in a mammal. An "effective amount" is intended to mean that amount of a compound that is sufficient to treat, prevent or inhibit malaria or a disease associated with malaria. In some suitable embodiments, malaria or the disease or disorder associated with malaria is caused by a Plasmodium parasite, suitably, P. falciparum, P. virax, P. ovale or P. malariae, thus it is the amount sufficient to, when administered to the subject, including a mammal, e.g., a human, to treat, prevent or inhibit malaria or a disease or a disorder associated with malaria or infection with a malaria parasite. The amount of a given compound of the present invention that will correspond to such an amount will vary depending upon various factors, such as the given drug or compound, the pharmaceutical formulation, the route of administration, the type of disease or disorder, the identity of the subject or host being treated, and the like, but can nevertheless be routinely determined by one skilled in the art. Also, as used herein, a "therapeutically effective amount" of a compound of the present invention is an amount which prevents, inhibits, suppresses or reduces malaria, e.g., as determined by clinical symptoms such as fever, anemia, and in severe cases, a coma potentially leading to death.

For administration to human patients, the total daily dose of the pantothenone compound of the invention is typically within the range 0.0001 mg/kg to 1000 mg/kg body weight, preferably 0.001 mg/kg to 250 mg/kg body weight, more preferably 0.005 mg/kg to 50 mg/kg body weight, most preferably 0.01 mg/kg to 10 mg/kg body weight, the exact amount depending of course on the mode of administration and/or the severity of the disease or condition. For example, daily dosages for treatment by intravenous administration will typically be much lower than for oral treatment.

As described herein before, the addition of a patothenamide can significantly enhance the action of the pantothenone (and vice versa). In this embodiment of the invention, the pantothenamide will typically be administered in an amount within the range of 0.00005 mg/kg to 500 mg/kg body weight, preferably 0.0005 mg/kg to 100 mg/kg body weight, more preferably 0.0025 mg/kg to 25 mg/kg body weight, most preferably 0.005 mg/kg to 5 mg/kg body weight. Amounts of the pantothenone to be used in combination therapy according to the invention may be lowered as compared to the above stated dosages for treatment with pantothenone alone, e.g. a factor 2, 3, 5 or 10 lower. The total daily dosage(s) may be administered in single or divided doses.

It is preferred that the compounds and combinations of the invention or the pharmaceutical compositions containing them are administered repeatedly. Preferably, the compound is administered once, twice or three times daily to the patient. Embodiments are also envisaged wherein the compound of the present invention is administered less than once daily, e.g. once every two days, once every three days, once every four days or once a week. Even less frequent administration may be feasible using depot formulations.

Treatment may commence before, during or after exposure to malaria or malaria parasite. The length of the treatment period depends on a variety of factors, such as the severity of the disease, the age of the patient, the concentration and the activity of the compounds of the present invention, or a combination thereof. Typically, treatment lasts at least a week, more preferably at least two weeks, more preferably at least three weeks. As is generally known by those skilled in the art, repeated and continued administration typically reduces the risks of development of resistance towards the antibiotic and, without wishing to be bound by any particular theory, it is hypothesized that this might apply to compounds and combinations of the present invention.

It will also be appreciated that the effective dosage of the compound used for the treatment or prophylaxis may increase or decrease over the course of a particular treatment or prophylaxis regime. Changes in dosage may result and become apparent by standard diagnostic assays known in the art. In some instances, chronic administration may be required.

The compounds and combinations of the invention or the pharmaceutical compositions containing them can be administered through any of the conventional routes. Oral administration may involve swallowing, so that the compound enters the gastrointestinal tract, or buccal or sublingual administration may be employed by which the compound enters the blood stream directly from the mouth. Parenteral administration may involve administration directly into the blood stream, into muscle, or into an internal organ. Suitable means for parenteral administration include intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intraurethral, intrasternal, intracranial, intramuscular and subcutaneous. Suitable devices for parenteral administration include needle (including microneedle) injectors, needle-free injectors and infusion techniques. The compounds of the invention may furthermore be administered via the intranasal or pulmonal route. It is preferred that the compounds of the invention, the combinations thereof or the pharmaceutical or veterinary compositions containing them are administered orally or parenterally, preferably orally or intravenously.

Compounds of the invention or combinations thereof may be administered to a human or animal subject either alone or as part of a pharmaceutical composition

Another aspect of the invention concerns pharmaceutical compositions comprising a pantothenone compound as defined in any of the foregoing or a combination of a pantothenone and a pantothenamide as defined above. Generally, they will be administered as a formulation in association with one or more pharmaceutically acceptable excipients. The term "excipient" is used herein to describe any ingredient other than the compound(s) of the invention. The choice of excipient will, to a large extent, depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

In a preferred embodiment of the invention a pharmaceutical composition for use in humans is provided comprising one or more pantothenone compounds of the invention in a total amount within the range of 0.001 mg to 1000 mg, preferably 0.01 mg to 250 mg, more preferably 0.05 mg to 100 mg, most preferably 0.1 to 50 mg.

As described herein before, the addition of a patothenamide can significantly enhance the action of the pantothenone. Hence amounts of the pantothenone to be used in combination preparations of the invention will typically be lower, e.g. a factor 2, 3, 5 or 10 lower. In this embodiment of the invention, the pantothenamide will typically be employed in an amount within the range of 0.001 mg to 1000 mg, preferably 0.01 mg to 250 mg, more preferably 0.05 mg to 100 mg, most preferably 0.1 to 50 mg.

Compositions suitable for the delivery of compounds or combinations of the present invention and methods for their preparation will be readily apparent to those skilled in the art. Such compositions and methods for their preparation may be found, for example, in 'Remington's Pharmaceutical Sciences', 19th Edition (Mack Publishing Company, 1995).

Particularly suitable formulations for oral therapeutic administration,include tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Formulations suitable for oral administration include solid formulations such as tablets, capsules containing particulates, liquids, or powders, lozenges (including liquid-filled), chews, multi- and nano- particulates, gels, solid solution, liposome, films, ovules, sprays and liquid formulations.

Liquid formulations include suspensions, solutions, syrups and elixirs. Such formulations may be employed as fillers in soft or hard capsules and typically comprise a carrier, for example, water, ethanol, polyethylene glycol, propylene glycol, methylcellulose, or a suitable oil, and one or more emulsifying agents and/or suspending agents. Liquid formulations may also be prepared by the reconstitution of a solid, for example, from a sachet. The compounds of the invention may also be used in fast-dissolving, fast-disintegrating dosage forms such as those described in Expert Opinion in Therapeutic Patents, 1 1 (6), 981- 986, by Liang and Chen (2001).

For tablet dosage forms, depending on dose, the drug may make up from 1 weight % to 80 weight % of the dosage form, more typically from 5 weight % to 60 weight % of the dosage form. In addition to the drug, tablets generally contain a disintegrant. Examples of disintegrants include sodium starch glycolate, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, croscarmellose sodium, crospovidone, polyvinylpyrrolidone, methyl cellulose, microcrystalline cellulose, lower alkyl -substituted hydroxypropyl cellulose, starch, pregelatinised starch and sodium alginate. Generally, the disintegrant will comprise from 1 weight % to 25 weight %, preferably from 5 weight % to 20 weight % of the dosage form. Binders are generally used to impart cohesive qualities to a tablet formulation. Suitable binders include microcrystalline cellulose, gelatin, sugars, polyethylene glycol, natural and synthetic gums, polyvinylpyrrolidone, pregelatinised starch, hydroxypropyl cellulose and hydroxypropyl methylcellulose. Tablets may also contain diluents, such as lactose (monohydrate, spray-dried monohydrate, anhydrous and the like), mannitol, xylitol, dextrose, sucrose, sorbitol, microcrystalline cellulose, starch and dibasic calcium phosphate dihydrate. Tablets may also optionally comprise surface active agents, such as sodium lauryl sulfate and polysorbate 80, and glidants such as silicon dioxide and talc. When present, surface active agents may comprise from 0.2 weight % to 5 weight % of the tablet, and glidants may comprise from 0.2 weight % to 1 weight % of the tablet. Tablets also generally contain lubricants such as magnesium stearate, calcium stearate, zinc stearate, sodium stearyl fumarate, and mixtures of magnesium stearate with sodium lauryl sulphate. Lubricants generally comprise from 0.25 weight % to 10 weight %, preferably from 0.5 weight % to 3 weight % of the tablet. Other possible ingredients include anti-oxidants, colourants, flavouring agents, preservatives and taste- masking agents. Exemplary tablets contain up to about 80% drug, from about 10 weight % to about 90 weight % binder, from about 0 weight % to about 85 weight % diluent, from about 2 weight % to about 10 weight % disintegrant, and from about 0.25 weight % to about 10 weight % lubricant. Tablet blends may be compressed directly or by roller to form tablets. Tablet blends or portions of blends may alternatively be wet-, dry-, or melt-granulated, melt congealed, or extruded before tabletting. The final formulation may comprise one or more layers and may be coated or uncoated; it may even be encapsulated. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets may be coated with shellac, sugar or both. A syrup or elixir may contain the active compounds sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring, such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed. In addition, the active compounds may be incorporated into sustained-release preparation and formulations. The formulation of tablets is discussed in Pharmaceutical Dosage Forms: Tablets, Vol. 1 , by H. Lieberman and L. Lachman (Marcel Dekker, New York, 1980). Suitable modified release formulations for the purposes of the invention are, such as high energy dispersions and osmotic and coated particles, are to be found in Pharmaceutical Technology On-line, 25(2), 1- 14, by Verma et al (2001 ). The use of chewing gum to achieve controlled release is described in WO 00/35298.

A compound or combination of the invention may also be administered parenterally. Solutions of a compound of the invention can be prepared in water suitably mixed with a surfactant such as hydroxypropylcellulose. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, DMSO and mixtures thereof with or without alcohol, and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms. A person skilled in the art would know how to prepare suitable formulations. Conventional procedures and ingredients for the selection and preparation of suitable formulations are described, for example, in Remington's Pharmaceutical Sciences (2003-20th edition) and in The United States Pharmacopeia: The National Formulary (USP 24 NF19) published in 1999. The pharmaceutical forms suitable for injectable use include aqueous solutions or dispersions as well as powders for the extemporaneous preparation of injectable solutions or dispersions. In all cases the form must be sterile. Furthermore the final injectable must be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms, such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), suitable mixtures thereof, and vegetable oils. The proper fluidity can be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin. Sterile injectable solutions are prepared by incorporating the active compounds in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle which contains the basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum-drying and freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile- filtered solution thereof. Parenteral formulations are typically aqueous solutions which may contain excipients such as salts, carbohydrates and buffering agents (preferably to a pH of from 3 to 9), but, for some applications, they may be more suitably formulated as a sterile non-aqueous solution or as a dried form to be used in conjunction with a suitable vehicle such as sterile, pyrogen-free water. The preparation of parenteral formulations under sterile conditions, for example, by lyophilisation, may readily be accomplished using standard pharmaceutical techniques well known to those skilled in the art. The solubility of compounds used in the preparation of parenteral solutions may be increased by the use of appropriate formulation techniques, such as the incorporation of solubility- enhancing agents. Formulations for parenteral administration may be formulated to be immediate and/or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release. Thus compounds of the invention may be formulated as a solid, semi-solid, or thixotropic liquid for administration as an implanted depot providing modified release of the active compound. Examples of such formulations include drug-coated stents and poly(c//-lactic-coglycolic)acid (PGLA) microspheres.

The compounds of the invention may be combined with soluble macromolecular entities, such as cyclodextrin and suitable derivatives thereof or polyethylene glycol- containing polymers, in order to improve their solubility, dissolution rate, taste-masking, bioavailability and/or stability for use in any of the aforementioned modes of administration. Drug-cyclodextrin complexes, for example, are found to be generally useful for most dosage forms and administration routes. Both inclusion and non-inclusion complexes may be used. As an alternative to direct complexation with the drug, the cyclodextrin may be used as an auxiliary additive, i.e. as a carrier, diluent, or solubiliser.

As will be understood by those skilled in the art, the present invention provides compositions comprising combinations of the active components of this invention, e.g. combinations of pantothenones as well as combinations of one or more pantothenones and one or more pantothenamides.

The compounds and combinations of the active components of this invention, can also be employed in conjunction with other modes of treatment of malaria. Such combined treatment may result in further enhancement of the efficacy of the treatment. Such further enhancement may be additive or even synergistic.

Suitable examples of such other modes of treatment comprise co-administration of other antimalaria agents, such as Atovaquone, Chloroquine, Hydroxychloroquine, Primaquine, Proguanil, Quinidine, Quinine, Sulfadoxine and Pyrimethamine, mefloquine, and artemisinin. One example of new compounds invented to use for the treatment of malaria is phenazines, especially riminophenazines, which have a substituted imino group in one benzene ring. In particular, N,5-bis-(phenyl)-3,5-dihydro-3-(cyclohexylimino)-2- phenazinamine has been reported to show antimalarial activity.

Another class of therapeutic agents which may suitably be used in conjunction with the antibiotic compounds or combinations of the invention include the so-called resistance modifying agents. Resistance modifying agents may target and inhibit multiple drug resistance (MDR) mechanisms, rendering the parasite susceptible to antibiotics to which they were previously resistant.

As used herein, the terms "co-administration", "co-administered" and "in combination with", referring to the compounds of the invention and, optionally, the one or more other therapeutic agents, is intended to mean, and does refer to and include the following:

· simultaneous administration of such combination of compounds, when such components are formulated together into a single dosage form which releases said components at substantially the same time following administration,

• substantially simultaneous administration of such combination of compounds, when such components are formulated apart from each other into separate dosage forms which are administered at substantially the same time, where after said components are released at substantially the same time,

• sequential administration of such combination of compounds, when such components are formulated apart from each other into separate dosage forms which are administered at consecutive times with a significant time interval between each administration; and

It is within the scope of the present invention that two or more pharmaceutical compositions, at least one of which contains an anitbiotic pantothenamide derivative in accordance with the invention, may conveniently be combined in the form of a kit suitable for co-administration of the compositions. Thus a kit of the invention typically comprises two or more separate pharmaceutical or veterinary composition, at least one of which contains an antibiotic pantothenamide derivative in accordance with the invention as well as means for separately retaining said composition, such as a container, divided bottle, or divided foil packet. An example of such a kit is the familiar blister pack used for the packaging of tablets, capsules and the like. In a particularly preferred embodiment of the invention the kit comprises two or more separate pharmaceutical compositions, at least one of which contains an antibiotic pantothenamide derivative in accordance with the invention while another one contains a pantetheinase activity reducing/inhibiting agant in accordance with the invention, as well as means for separately retaining said compositions.

In this document and in its claims, the verb "to comprise" and its conjugations is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. In addition, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article "a" or "an" thus usually means "at least one".

The invention will be illustrated in more detail in the following examples, which are in no way intended to limit the scope of the invention.

Example 1: Synthesis of compounds of the invention

All reactions were performed under an argon atmosphere, unless stated otherwise. Solvents were distilled from appropriate drying agents prior to use. Et₃N was distilled and stored over KOH. All other chemicals were purchased from commercial suppliers and were used without further purification, unless stated otherwise. Reactions were followed, and Revalues are obtained using thin layer chromatography (TLC) on silica gel-coated plates (Merck 60 F254) with the indicated eluent and compounds were detected with UV-light and/or by charring at ca. 150 °C after dipping into a solution of potassium permanganate, or ninhydrin. Column or flash chromatography was carried out using ACROS silica gel (0.035-0.070 mm, pore diameter ca. 6 mm). IR spectra were recorded on an ATI Mattson Genesis Series FTIR spectrometer. High-resolution mass spectra were recorded on a JEOL AccuTOF (ESI) or a MAT900 (EI, CI, and ESI). Melting points were analyzed with a Buchi melting point B-545 and are not corrected. NMR spectra were recorded at 298 K on a Bruker DMX 300 (300 MHz) and a Varian 400 (400 MHz) spectrometer in the solvent indicated. Chemical shifts are given in parts per million (ppm) with respect to tetramethylsilane (0.00 ppm), or CHD₂OD (3.31 ppm) as internal standard for 1H-NMR; and CDC1₃ (77.16 ppm), or CD₃OD (49.00 ppm) as internal standard for ¹³C-NMR. Coupling constants are reported as J values in hertz (Hz).

(R)-3-(2,2,5,5-tetramethyl-l,3-dioxane-4-carboxamido)propanoic acid (1)

To a solution of pantothenic acid (4.47 g, 20.4 mmol) in a mixture of dry CH₂Cl₂/acetone (200 mL, 1 : 1 v/v) at 0 °C, were added 2-

methoxyprop-l-ene (3.77 mL, 2.0 equiv) and pTsOH (119 mg, 3 mol %). After 15 min the reaction mixture was allowed to warm to rt. After 2 h the reaction was quenched with saturated aqueous NaHC0₃ (2 mL), dried (Na₂S0₄), and concentrated in vacuo. The crude product was purified by flash column chromatography (MeOH/CH₂Cl₂, 0: 1→2:3) to afford 1 (4.98 g, 94% yield) as a colorless oil. R/ 0.15 (MeOH/CH₂Cl₂, 1 :9). 1H NMR (CDC1₃, 400 MHz): δ 7.62 (t, J = 5.3 Hz, 1H), 4.12 (s, 1H), 3.73 (d, J = 11.7 Hz, 1H), 3.56-3.38 (m, 2H), 3.27 (d, J = 11.7 Ηζ,ΙΗ), 2.52 (t, J = 6.7 Hz, 2H), 1.44 (s, 6H), 0.99 (s, 3H), 0.97 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 175.2, 171.9, 100.2, 78.2, 72.2, 35.5, 34.5, 33.8, 29.7, 22.4, 19.3, 19.1.

(R)-N- {3- [methoxy(methyl)amino] -3-oxopropyl}-2,2,5,5-tetr amethyl- 1 ,3-dioxane-4- carboxamide (2)

To a solution of 1 (1.80 g, 6.92 mmol) in dry CH₂C1₂ (65 mL) at rt were added, EDC (2.09 g, 1.5 equiv), N,0-dimethylhydroxylamine

hydrochloride (1.04 g, 1.5 equiv) and DIPEA (3.43 mL, 3.0 equiv), followed by DMAP (483 mg, 0.5 equiv). The reaction mixture was stirred over night at rt, quenched with saturated aqueous NH₄C1 (40 mL), extracted with CH₂C1₂.( 3 x 50 mL), dried (Na₂S0₄), and concentrated in vacuo. The product was purified by column chromatography (MeOH/CH₂Cl₂, 0: 1→1 :4) to afford 2 (1.90 g, 91% yield) as a colorless oil. R_f 0.56 (MeOH/CH₂Cl₂, 1 :9). [<x]∞+44.5 (c 1.32, CH₂C1₂). IR (ATR) 3417, 3334, 2980, 2940, 2871,

1661, 1520, 1378, 1196, 1095, 873 cm^-1. 1H NMR (CDC1₃, 400 MHz): δ 7.13 (t, J = 5.7 Hz, 1H), 4.07 (s, 1H), 3.68 (d, J= 11.7 Hz, 1H), 3.67 (s, 3H), 3.64-3.48 (m, 2H), 3.27 (d, J= 11.7 Hz, 1H), 3.18 (s, 3H), 2.76-2.59 (m, 2H), 1.46 (s, 3H), 1.42 (s, 3H), 1.03 (s, 3H), 0.96 (s, 3H). ¹³C NMR (CDCI3, 75 MHz): δ 169.9, 99.1, 77.3, 71.6, 61.4, 34.2, 33.1, 32.3, 31.9, 29.6, 22.3, 19.0, 18.8. Ci₄H₂₆N₂0₅ (M+Na)⁺: 325.1739, found: 325.1746.

(R)-2,2,5,5-tetramethyl- V-(3-oxohept-6-en-l-yl)-l,3-dioxane-4-carboxamide (3)

To a solution of 2 (2.10 g, 6.95 mmol) in a mixture of dry Et₂0/THF (70 mL, 1 : 1 v/v) at 0 °C, was added dropwise 3-

butenylmagnesium bromide (28.0 mL of a 0.5 M solution in THF,

13.9 mmol, 2.0 equiv). After 15 min the reaction mixture was allowed to warm to rt and stirred for 4 h. Next, saturated aqueous NH₄C1 was added to quench the reaction, followed by extraction with CH₂C1₂ (3 x 70 mL). The organic layers were combined, dried (Na₂S0₄), and concentrated in vacuo. The product was purified by column chromatography (EtO Ac/heptane, 0: 1→1 :2) to afford 3 (1.23 g, 59% yield) as a colorless oil. R_f 0.86 (MeOH/CH₂Cl₂, 1 :9). [o¾° +44.1 (c 1.38, CH₂C1₂). IR (ATR) 3421, 2915, 2849, 1709, 1666, 1519, 1377, 1092, 871,

701 cm^-1. 1H NMR (CDC1₃, 400 MHz): δ 6.96-6.87 (m, 1H), 5.79 (ddt, J= 6.5, 10.2, 16.7 Hz, 1H), 5.05-4.96 (m, 2H), 4.05 (s, 1H), 3.68 (d, J = 1 1.7 Hz, 1H), 3.58-3.42 (m, 2H), 3.27 (d, J = 11.7 Hz, 1H), 2.68 (t, J = 6.0 Hz, 2H), 2.53-2.49 (m, 2H), 2.36-2.30 (m, 2H), 1.46 (s, 3H), 1.41 (s, 3H), 1.04 (s, 3H), 0.95 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 209.2, 169.9, 136.9, 115.6, 99.1, 77.3, 71.6, 42.3, 42.1, 33.4, 33.1, 29.6, 27.8, 22.3, 19.0, 18.8. HRMS (ESI) m/z calcd for Ci₆H₂₇Ni0₄Na (M+Na)⁺: 320.1838, found: 320.1837.

(R)-2,2,5,5-tetramethykV- [3-oxo-3-(pentylamino)pr opyl] - 1 ,3-dioxane-4-carboxamide (4)

Prepared as described for 2, starting from 1 (3.40 g, 13.1 mmol) and n-amylamine (2.30 mL, 1.5 equiv). Column

chromatography (EtO Ac/heptane, 0: 1— >4: 1) afforded 4 (1.89 g, 44% yield) as a white solid. R_f 0.56 (MeOH/CH₂Cl₂, 1 :9). Mp 81.5 °C. [<x]∞+41.6 (c 1.01,

CH₂C1₂). IR (ATR) 3430, 3317, 3300, 2954, 2931, 2868, 1649, 1526, 1463, 1377, 1197, 1098, 873 cm^-1. 1H NMR (CDCI3, 400 MHz): δ 7.02 (t, J = 5.2 Hz, 1H), 5.88-5.84 (m, 1H), 4.07 (s, 1H), 3.68 (d, J = 11.7 Hz, 1H), 3.64-3.46 (m, 2H), 3.28 (d, J = 11.7 Hz, 1H), 3.26-3.21 (m, 2H), 2.43 (t, J = 6.2 Hz, 2H), 1.49 (dt, J = 7.3, 14.6 Hz, 2H), 1.46 (s, 3H), 1.42 (s, 3H), 1.38- 1.24 (m, 4H), 1.04 (s, 3H), 0.97 (s, 3H), 0.90 (t, J= 6.8 Hz, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 170.9, 170.3, 99.2, 77.3, 71.6, 39.7, 36.4, 35.1, 33.1, 29.6, 29.4, 29.2, 22.5, 22.3, 19.0, 18.8, 14.1. HRMS (ESI) m/z calcd for Ci₇H₃₃N₂0₄ (M+H)⁺: 329.2440, found: 329.2426.

(R)- V-[3-(heptylamino)-3-oxopropyl]-2,2,5,5-tetramethyl-l,3-dioxane-4-carboxamide (5)

Prepared as described for 2, starting from 1 (4.50 g, 17.4 mmol) and n-heptylamine (3.90 mL, 1.5 equiv). Column

chromatography (EtO Ac/heptane, 1 :2— 1 :0) afforded 5 (3.15 g, 51% yield) as a colorless oil. R_f 0.56 (MeOH/CH₂Cl₂, 1 :9). [o¾° +39.4 (c 1.00,

CH₂C1₂). IR (ATR) 3425, 3321, 2927, 2863, 1650, 1526, 1459, 1377, 1196, 1098, 875 cnT¹. 1H NMR (CDC1₃, 400 MHz): δ 7.04 (t, J = 5.9 Hz, 1H), 6.03 (t, J = 4.9 Hz, 1H), 4.06 (s, 1H), 3.68 (d, J = 11.7 Hz, 1H), 3.63-3.46 (m, 2H), 3.28 (d, J = 11.7 Hz, 1H), 3.26-3.20 (m, 2H), 2.42 (t, J= 6.2 Hz, 2H), 1.53-1.47 (m, 2H), 1.46 (s, 3H), 1.41 (s, 3H), 1.32-1.24 (m, 8H), 1.03 (s, 3H), 0.97 (s, 3H), .88 (t, J= 6.9 Hz, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 170.8, 170.2, 99.1, 77.1, 71.5, 39.6, 36.2, 35.0, 33.0, 31.7, 29.6, 29.5, 29.0, 26.9, 22.6, 22.2, 18.9, 18.7, 14.1. HRMS (ESI) m/z calcd for Ci₉H₃₇N₂0₄ (M+H)⁺: 357.2753, found: 357.2747.

(R)-2,4-dihydroxy-3,3-dimethyl- V-(3-oxohept-6-en-l-yl)butanamide (RR2, 6)

To a solution of 3 (30 mg, 0.10 mmol) in MeCN (1.0 mL) was added, BiCl₃ (6.5 mg, 20 mol%), followed by distilled H₂0 (36

μί, 20 equiv). The reaction was stirred at rt for 4 h, then filtered and concentrated in vacuo. After dilution with EtO Ac (10 mL), the reaction mixture was washed with saturated aqueous NaHC0₃ (2 x 8 mL) and the aqueous layer was extracted with EtOAc (3 >< 8 mL). The organic layers were combined, dried (Na₂S0₄), and concentrated in vacuo. The product was purified by column chromatography (EtO Ac/heptane, 1 : 1— 1 :0) to afford 6 (24 mg, 92% yield) as a colorless oil. R/ 0.52 (MeOH/CH₂Cl₂, 1 :9). [<x]∞ +32.6 (c 1.18, CH₂C1₂). IR (ATR) 3347, 2955, 2872, 1706, 1646, 1532, 1079, 1041, 919 cm^-1. 1H NMR (CDC1₃, 400 MHz): δ 7.25 (t, J = 6.0 Hz, 1H), 5.78 (ddt, J = 6.5, 10.2, 16.7 Hz, 1H), 5.03 (ddd, J = 1.3, 3.4, 16.7 Hz, 1H), 4.99 (ddd, J = 1.3, 3.4, 10.2 Hz, 1H), 4.16 (d, J = 4.5 Hz, 1H), 3.98 (d, J = 4.3 Hz, 1H), 3.66 (bs, 1H), 3.59-3.45 (m, 4H), 2.70 (t, J = 5.9 Hz, 2H), 2.53 (t, J = 7.4 Hz, 2H), 2.35- 2.30 (m, 2H), 0.98 (s, 3H) 0.89 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 209.6, 173.4, 136.8, 115.6, 77.6, 71.2, 42.2, 42.0, 39.4, 33.8, 27.7, 21.4, 20.4. Ci₃H₂₄Ni0₄ (M+H)⁺: 258.1705, found: 258.1699. (R)-2,4-dihydroxy-3,3-dimethyl- V-[3-oxo-3-(pentylamino)propyl]butanamide ( V5Pan, 7)

\ / ^{0 0} Prepared as described for 6, starting from 4 (1.80 g, 5.65

HO.

N

H mmol). Column chromatography (MeOH/CH₂Cl₂, 0: 1→1 :9) afforded 7 (1.22 g, 75% yield) as a white solid. R_f 0.46 (MeOH/CH₂Cl₂, 1 :9). Mp 89.4 °C. [o¾° +29.7 (c 1.00, MeOH). IR (ATR) 3330, 3280, 3088, 2937, 2872, 1642, 1546, 1089,

1033, 691 cm^-1. 1H NMR (CD₃OD, 400 MHz): δ 3.88 (s, 1H), 3.54-3.37 (m, 4H), 3.17-3.13 (m, 2H), 2.41 (t, J = 6.7 Hz, 2H), 1.53-1.46 (m, 2H), 1.40-1.27 (m, 4H), 0.94-0.90 (m, 9H). ¹³C NMR (CDCls, 75 MHz): δ 174.1, 171.6, 77.5, 70.9, 39.8, 39.4, 35.9, 35.4, 29.2, 22.4, 21.4, 20.6, 14.1 HRMS (ESI) m/z calcd for Ci₄H₂₈N₂0₄Na (M+Na)⁺: 311.1947, found: 311.1933.

(R)- V-[3-(heptylamino)-3-oxopropyl]-2,4-dihydroxy-3,3-dimethylbutanamide ( V7Pan, 8)

Prepared as described for 6, starting from 5 (2.90 g, 8.13 mmol). Column chromatography (MeOH/CH₂Cl₂,

0: 1→1 :9) afforded 8 (2.21 g, 86% yield) as a white solid. R/ 0.47 (MeOH/CH₂Cl₂, 1 :9). Mp 78.2 °C. [a]∞+26.9 (c 1.01, MeOH). IR (ATR) 3352, 2483, 2068, 1119, 973 cm^-1. 1H NMR

(CD₃OD, 400 MHz): δ 3.89 (s, 1H), 3.54-3.37 (m, 4H), 3.15 (dt, J = 1.2, 6.9 Hz, 2H), 2.41 (t, J= 6.7 Hz, 2H), 1.53-1.46 (m, 2H), 1.32-1.31 (m, 8H), 0.92-0.89 (m, 9H). ¹³C NMR (CD₃OD, 75 MHz): δ 176.1, 173.6, 77.3, 70.4, 40.5, 40.4, 36.4, 32.9, 30.4, 30.1, 28.0, 23.7, 21.3, 20.9, 14.4. HRMS (ESI) m/z calcd for Ci₆H₃₃N₂0₄ (M+H)⁺: 317.2440, found: 317.2429.

(R)-2,2,5,5-tetramethyl- V-(3-oxo-5-phenylbutyl)-l,3-dioxane-4-carboxamide (9)

Prepared as described for 3, starting from 2 (1.90 g, 6.27 mmol) and benzylmagnesium chloride (6.43 mL of a 2.0 M solution in THF,

12.9 mmol, 2.05 equiv). Column chromatography (EtO Ac/heptane,

0: 1→1 : 1) afforded 9 (827 mg, 40% yield) as a colorless oil. R/ 0.69 (EtO Ac). [<x]∞+41.1 (c I . I5. CH2CI2). IR (ATR) 3430, 2993, 2950, 2868, 2358, 1713, 1670, 1522, 1377, 1 196, 1095 cm^"1. 1H NMR (CDCI3, 300 MHz): δ 7.35-7.17 (m, 5H), 6.88 (m, 1H), 4.02 (s, 1H), 3.68 (s, 2H), 3.65 (d, J = 11.7 Hz, 1H), 3.55-3.38 (m, 2H), 3.25 (d, J = 11.7 Hz, 1H), 2.73-2.69 (m, 2H), 1.45 (s, 3H), 1.40 (s, 3H), 1.01 (s, 3H), 0.88 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 207.4, 169.8, 133.8, 129.4, 128.9, 127.3, 99.1, 71.5, 50.3, 41.5, 33.3, 33.0, 29.5, 22.2, 18.9, 18.8. HRMS (ESI) m/z calcd for Ci₉H₂₈N0₄ (M +H)⁺, 334.2018; found, 334.2017. (R)-2,4-dihydroxy-3,3-dimethyl- V-(3-oxo-5-phenylbutyl)butanamide (RR6, 10)

Prepared as described for 6, starting from 9 (367 mg, 1.10 mmol). Column chromatography (EtO Ac/heptane, 0: 1— »1 :0)

afforded 10 (197 mg, 61% yield) as a colorless oil. R_f 0.30 (EtO Ac). [o¾° +28.7 (c 1.17, CH₂C1₂). IR (ATR) 3372, 3058, 3036, 2960, 2868, 1710, 1643, 1530, 1496, 1453, 1366, 1287, 1076, 1041 cm^"1 1H NMR (CDC1₃, 300 MHz): δ 7.36-7.18 (m, 5H), 7.07 (m, 1H), 3.93 (s, 1H), 3.69 (s, 2H), 3.52-3.45 (m, 2H), 3.42 (m, 2H), 3.05 (br s, 1H), 2.73 (t, J = 5.6 Hz, 2H), 1.72 (br s, 1H), 0.95 (s, 3H), 0.83 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 207.9, 173.2, 133.7, 129.5, 129.0, 127.4, 77.6, 71.3, 50.3, 41.4, 39.4, 33.8, 21.5, 20.3. HRMS (ESI) m/z calcd for Ci₆H₂₄N0₄ (M+H)⁺, 294.1705; found 294.1694.

(R)-2,2,5,5-tetramethyl- V-(3-oxo-5-phenylpentyl)-l,3-dioxane-4-carboxamide (11)

Prepared as described for compound 3, starting from 2 (1.03 g, 3.40 mmol) and phenethylmagnesium chloride (6.96 mL of a 1.0

M solution in THF, 6.96 mmol, 2.05 equiv). After stirring for 2 h, the reaction mixrure was worked up to yield compound 11 (0.754 g, 64%) as a colorless oil. R/ 0.71 (EtO Ac). [<x]∞ +37.7 (c 1.07, CH₂C1₂). IR (ATR): 3426, 3334, 2989, 2952, 2870,

2362, 2332, 1712, 1671, 1521 , 1377, 1197, 1095 cm^"1. 1H NMR (CDC1₃, 300 MHz): δ 7.30 - 6.94 (m, 5H), 6.94-6.90 (m, 1H), 4.05 (s, 1H), 3.67 (d, J = 11.7 Hz, 1H), 3.58-3.39 (m, 2H), 3.27 (d, J = 11.7 Hz, 1H), 2.90 (m, 2H), 2.76-2.70 (m, 2H), 2.65 (t, J = 6.0 Hz, 2H), 1.47 (s, 3H), 1.41 (s, 3H), 1.03 (s, 3H), 0.93 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 209.0, 169.9, 140.9, 128.7, 128.4, 126.3, 99.2, 77.3, 71.6, 44.5, 42.4, 33.4, 33.1, 29.8, 29.6, 28.5, 22.3, 19.0, 18.8. HRMS (ESI) m z calcd for C₂₀H₃₀NO₄ (M+H)⁺, 348.2175; found 348.2175.

(R)-2,4-dihydroxy-3,3-dimethyl- V-(3-oxo-5-phenylpentyl)butanamide (RR7, 12)

Prepared as described for 6, starting from compound 11 (366 mg, 1.053 mmol), compound 12 (260 mg, 80%>) was obtained

as a colorless oil. R/0.33 (EtO Ac). [<x]∞ +28.6 (c 1.61, CH₂C1₂). IR (ATR): 3354, 2933, 2859, 1708, 1644, 1529, 1452, 1369, 1287, 1075, 1041 cm^"1. 1H NMR (CDC1₃, 300 MHz): δ 7.31- 7.15 (m, 5H), 7.09 (m, 1H), 3.96 (s, 1H), 3.58 (br s, 1H), 3.54-3.42 (m, 4H), 3.12 (br s, 1H), 2.92-2.87 (m, 2H), 2.78-2.72 (m, 2H), 2.66 (t, J= 5.8 Hz, 2H), 0.99 (s, 3H), 0.87 (s, 3H). ¹³C NMR (CDCI3, 75 MHz): δ 209.4, 173.1, 140.8, 128.7, 128.4, 126.4, 77.7, 71.3, 44.4, 42.3, 39.5, 33.9, 29.7, 21.6, 20.3. HRMS (ESI) m/z calcd for C17H26NO4 (M+H)⁺, 308.1861; found 308.1851.

(R)-2,2,5,5-tetramethyl-N-(3-oxo-6-phenylhexyl-l,3-dioxane-4-carboxamide (13)

Three drops of 1 ,2-dibromoethane were added to a suspension of magnesium turnings (1.00 g, 41.2 mmol, 12.0 equiv) in

diethyl ether (20 mL) and the misture was briefly heated. Next, a solution of (3-bromopropyl)benzene (3.08 mL, 20.2 mmol, 6.0 equiv) in diethyl ether (20 mL) was added at such a rate that the mixture kept refluxing, after which the clouded solution was stirred for 2 h. The resulting Grignard reagent was added dropwise to a cooled (0 °C) solution of compound 2 (1.02 g, 3.37 mmol) in THF (20 mL) and stirred at 0 °C for 3.5 h. The reaction mixture was quenched with saturated aqueous NH₄C1 (100 mL), extracted with dichloromethane (3 x 70 mL), dried over Na₂S0₄ and concentrated. The crude product was purified by flash column chromatography (heptane/EtOAc, 1 :0→ 1 : 1), yielding compound 13 (0.95 g, 78%) as a colorless oil. R/0 0 (EtOAc), [<x]∞ +34.4 (c 1.23, CH₂C1₂). IR (ATR):

3421, 2997, 2947, 2872, 1710, 1672, 1522, 1454, 1377, 1260, 1222, 1197, 1159, 1096 cm^"1. 1H NMR (CDCI3, 300 MHz): δ 7.31-7.14 (m, 5H), 6.92 (m, 1H), 4.05 (s, 1H), 3.67 (d, J = 11.7 Hz, 1H), 3.56-3.41 (m, 2H), 3.27 (d, J= 11.7 Hz, 1H), 2.64 (t, J= 6.1 Hz, 2H), 2.61 (t, J = 6.0 Hz, 2H), 2.41 (t, J = 7.3 Hz, 2H), 1.91 (quintet, J = 7.7 Hz, 2H), 1.45 (s, 3H), 1.40 (s, 3H), 1.03 (s, 3H), 0.94 (s, 3H). ¹³C NMR (CDC1₃, 75 MHz): δ 209.8, 169.9, 141.5, 128.6, 126.2, 99.2, 77.3, 71.6, 42.2, 42.1, 35.1, 33.5, 33.1 29.6, 25.3, 22.3, 19.0, 18.8. HRMS (ESI) m/z calcd for C₂iH₃₂N0₄ (M+H)⁺, 362.2331; found 362.2352.

(R)-2,4-dihydroxy-3,3-dimethyl- V-(3-oxo-6-phenylhexyl)butanamide (RR8, 14)

Prepared as described for 6, starting from compound 13 (380 mg, 1.05 mmol), compound 14 (268 mg, 79%) was

obtained as a colorless oil. R/ 0.36 (EtOAc). [<x]∞ +26.6 (c 1.16, CH₂C1₂). IR (ATR): 3358,

3028, 2946, 2868, 1708, 1643, 1530, 1453, 1368, 1269 cm^"1. 1H NMR (CDC1₃, 300 MHz): δ 7.13-7.1 1 (m, 5H), 3.98 (s, 1H), 3.54-3.43 (m, 5H), 3.04 (br s, 1H), 3.66-3.59 (m, 4H), 2.42 (t, J = 7.4 Hz, 2H), 1.91 (quintet, J = 7.5 Hz, 2H), 1.00 (s, 3H), 0.88 (s, 3H). ¹³C NMR (CDCI3, 75 MHz): δ 210.2, 173.1, 141.5, 128.6, 126.2, 77.7, 71.3, 42.2, 42.1, 39.5, 35.1, 33.9, 25.2, 21.5, 20.3. HRMS (ESI) m z calcd for Ci₈H₂₈N0₄ (M+H)⁺, 322.2018; found 322.2009. Example 2: anti-malaria and pantetheinase inhibitory activity of the substances and composition of the invention Pantheteinase activity

Pantetheinase activity was measured by the amount of free aminomethylcoumarin (AMC) released by the hydrolysis of the pantetheine-analogue pantothenate- AMC. Pantothenate- AMC was incubated in phosphate buffer (100 mM potassium phosphate buffer pH 8.0) in the presence of serum or plasma as pantetheinase source with or without a potential pantetheinase inhibitor. In time, samples were taken and the reaction was terminated by addition of 100 mM CaC0₃ pH 10.5. Fluorescence was measured using a luminescence spectrometer (LS55, Perkin Elmer, EX 350 ± 2.5 nm, EM 450 ± 2.5 nm) against samples without serum or plasma as negative control. Mass spectrometric analysis

The pantothenamide N7Pan was incubated in phosphate buffer (500 μΜ potassium phosphate buffer pH 8.0) for 24 hours at 37 °C with or without potential pantetheinase inhibitors in the presence of 1% human serum as pantetheinase source. Prior to analysis samples were diluted 100-fold in methanol (HPLC grade, Fisher Scientific). Mass spectrometry was performed on a JEOL JMS-T100CS (AccuTOF CS) connected to a Agilent 1100 series HPLC system. Analysis was performed in infusion mode, 3 μΐ of sample was injected into a stream of methanol (HPLC grade, Fisher Scientific) containing 0.1% formic acid (puriss. Pa for mass spectrometry, Fluka) and 50 nanomolar PPG425 (poly[propylene glycol] average M.W. 425, Sigma- Aldrich Chemie GmbH) for use as an internal mass drift compensator. Total analysis time with a flow rate of ΙΟΟμΙ/min was 2.5 minutes per sample. Sample information elutes between 0.3 and 1.0 minutes. Data between 0 and 0.3 minutes was used to mass drift compensate the calibration against PPG425 peaks resulting in a mass precision better than 5 ppm. P.falciparum growth assays

P falciparum (strain NF54) is cultured in a human red blood cell suspension (5% hematocrit), using a starting parasitemia of 1-2%, in RPMI1640 medium with 10% human serum. Compounds to be tested for antimalaria activity are added at the start of the experiment. After 4 days blood smears are prepared, stained with Giemsa and the number of asexual stages (trophozoites and schizonts) is counted in approximately 4000-5000 red blood cells.

In vivo administration of RR6 to rats

Adult Wistar rats (Harlan, IN) received R 6 dissolved in PBS orally. Dosing was 2,

10 and 50 mg/kg, 3 rats per group. At several time points, approximately 200 microliter blood samples were collected using a tail cut and immediately mixed with 10 ul EDTA (50 mM in PBS) to obtain plasma. After centrifugation (10 min 3000 rpm), pantetheinase activity was measured in plasma according to the method described above. Plasma pantetheinase activity was plotted as a fraction of the activity at t=0 (100% activity).

In vitro antimalarial effect of pantetheinase inhbitors

Pantothenic acid is a necessary cofactor for P '.falciparum survival. Given the knowledge that pantetheinases of the mammalian vanin family could liberate pantothenic acid from pantetheine, it is hypothesized that inhibition of human pantetheinases or inhibition of a hitherto unknown parasite pantetheinase, could reduce the bioavailability of pantothenic acid. This would potentially result in antimalarial activity of such inhibitors. For this reason a number of compounds were synthesized that were analogues of pantetheine but did not contain an amide bond at the position that corresponds with the amide bond between pantothenic acid and cysteamine present in pantetheine. Potent inhibitors of pantetheinase activity in human plasma or serum were identified in this way. Figure 1 illustrates the inhibition curves of 3 of these compounds. Among them are RR2 and R 6, two inhibitors with IC₅₀ values of 40 μΜ and 500 nM respectively.

Upon testing these compounds against P falciparum, cultured in human red blood cells in vitro, in the presence of serum, compounds RR2, RR6, RR7 and RR8 were found to show significant growth inhibitory activity with IC₅₀ values < 10 μΜ (figure 2, left panel). All four compounds had also anti-pantetheinase activity in the high nanomolar to low micromolar range.

The compounds 'RR1 ' ((R)-2,4-dihydroxy-N-((l-(2-hydroxyethyl)-lH-l,2,3-triazol-4- yl)methyl)-3,3-dimethylbutanamide), 'RR4' ((R)-2,4-dihydroxy-N-((l-(2-mercaptoethyl)-lH- 1 ,2,3-triazol-4-yl)methyl)-3,3-dimethylbutanamide) and 'RR5 '((R)-N-(2-cyanoethyl)-2,4- dihydroxy-3,3-dimethylbutanamide), that were tested as comparative examples, lacked in vitro antimalaria activity and were less or not at all active as pantetheinase inhibitors (data not shown). R 2, R 6, R 7 and R 8 all reduced the number of asexual stages at 1 and 10 μΜ concentration, as determined by counting of parasites in blood smears and caused abnormal morphology in the remaining parasites (figure 2, pictures in right hand panel). Antimalarial activity of pantothenamides and their synergy with pantetheinase inhbitors

Pantothenamides, of which N5Pan and N7Pan are the prototypes, have been described as antibacterial agents under certain in vitro culture conditions (Clifton,G., Bryant,S.R., and Skinner,C.G. 1970. N'-(substituted) pantothenamides, antimetabolites of pantothenic acid. Arch. Biochem. Biophys. 137:523-528), but are not known to have activity against malaria parasites (reviewed in Spry, C, Kirk,K., and Saliba,K.J. 2008. Coenzyme A biosynthesis: an antimicrobial drug target. FEMS Microbiol. Rev. 32:56-106). Figure 3 shows that N5Pan is a very weak inhibitor of F '.falciparum growth in vitro, only achieving > 90% inhibition at a clinically irrelevant concentration of 1 mM. As the malaria parasite cultures contain human serum, the possibility was considered that N5Pan could be degraded by serum-derived pantetheinase activity, thereby reducing its potency. Therefore P. falciparum infected blood was cultured in the presence of both N5Pan and the pantetheinase inhibitor RR6. Surprisingly, a combination of 1 μΜ RR6 and 5 μΜ N5Pan caused a profound (90%) inhibition of parasite growth (figure 4). In the absence of N5Pan, 1 μΜ RR6 is not or only weakly active against P .falciparum (figures 2 and 4). In the absence of RR6, N5Pan is only weakly active against P .falciparum in the 1-10 μΜ concentration range. This finding indicates a synergy between a pantothenamide and a pantetheinase inhibitor. It is hypothesized that prevention of N5Pan breakdown by RR6 exposes the antimalarial activity of N5Pan, resulting in an increase of the anti-parasite potency (IC90) by a factor of 10 compared to RR6 alone, and by a factor of 200 compared to N5Pan alone.

Mass spectrometric analysis of pantothenamide breakdown in human serum

Figures 5a-c illustrate breakdown of a pantothenamide by human serum. In this case N7Pan was chosen rather than N5Pan for reasons of easy detection of the free amide. Figure 5a: spectrum of N7Pan (m/z of the parent compound: 339). Figure 5b; spectrum of N7Pan following incubation with human serum resulting in the appearance of the heptylamine hydrolysis product (m/z: 116). Figure 5c: Spectrum of N7Pan incubated with human serum in the presence of pantetheinase inhibitor RR6. Degradation of N7Pan is prevented as witnessed by the absence of the heptylamine peak. The RR6 peak is present at m/z = 316. Pharmacodynamics of RR6 in vivo

Figure 6 depicts the activity of plasma pantetheinase in rats at different time points following oral administration of the pantetheinase inhibitor RR6 at 2, 10 and 50 mg/kg in 3 rats per dose. Plasma pantetheinase activity was measured and expressed as a percentage of the activity at time zero. In the highest dose group a nearly 100% inhibition was observed up to 12 hours after adminstration.

Description of the figures

Figure 1 : Inhibition of pantetheinase activity in human serum by a concentration range of compounds RR1, RR2 and RR6.

Figure 2: Effect of varying concentrations of 7 different compounds on P. falciparum growth in vitro. Only the four compounds with highest pantetheinase inhibitory activity (RR2, RR6, RR7, RR8) showed significant antimalarial activity.

The pictures at the right illustrate the reduction of malaria parasites visible in blood smears after 96 hours.

Figure 3: Effect of several concentrations of N5Pan on P. falciparum growth in vitro. Only at 1 mM a strong inhibition of > 90% was observed.

Figure 4: Combination of the pantetheinase inhibitor RR6 and the pantothenamide N5Pan causes strong (90%) growth inhibition of P. falciparum in vitro.

Figure 5a-c: Mass spectra of N7Pan (5a), N7Pan partially hydrolysed by incubation with human serum (5b) and a combination of N7Pan and RR6 incubated with human serum.

Figure 6: Graph of plasma pantetheinase activity in rats following oral administration of three doses of RR6.

Claims

1. Pantothenone compound selected from the group of substances represented by formula I or II, and pharmaceutically acceptable salts, esters, and prodrugs thereof:

wherein:

Pv¹, R² and R³ independently represent hydrogen alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl;

R⁴ represents a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each of which may optionally be substituted with hydroxyl, thiol, halogen and/or cyanide;

X¹ and X² independently represent hydrogen, hydroxyl, thiol, cyanide, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, sulfonamide, amide, pyrazole or imidazole;

X³ represents sulfur, oxygen or nitrogen, said nitrogen optionally being substituted by alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl;

m is an integer within the range of 1-6; and

n is an integer within in the range of 0-6.

2. Pantothenone compound according to claim 1 , wherein R³ represents hydrogen 3. Pantothene compound according to claim 1 or 2, wherein R¹ and R² are independently selected from the group of C₁ -C4 alkyl.

4. Pantothenone compound according to any one of the preceding claims, wherein R¹ and R² are methyl.

5. Pantothenone Compound according to any one of the preceding claims, wherein X¹ and X² represent hydroxyl

6. Pantothenone Compound according to any one of the preceding claims, wherein n is an integer within the range of 1-3, preferably 1.

7. Pantothenone compound according to any one of the preceding claims, represented by formula (la):

wherein

R⁴ represents an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide;

m is an integer within the range of 1-6;

or a pharmaceutically acceptable salt, ester, amide, or prodrug thereof.

Pantothenone compound according to any one of the preceding claims, wherein R⁴

9. Pantothenone compound according to claim 8, wherein m is 1, 2, 3 or 4, preferably 1 or 3. 10. Pantothenone compound according to any one of the preceding claims wherein m is 1 and R⁴ represents C2-C4 alkenyl, preferably C3 alkenyl.

11. Pantothenone compound according to any one of the preceding claims selected from 'RR2', 'ΡνΡνβ', 'RR7' and 'RR8' :

harmaceutically acceptable salts, esters, or prodrugs thereof.

Pantothenone Compound according to claim 1, represented by formula Ila:

wherein: R⁴ represents an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide;

X³ represents sulfur, oxygen or nitrogen, said nitrogen optionally being substituted by alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl;

m is an integer within the range of 1-6;

or a pharmaceutically acceptable salt, ester, amide, or prodrug thereof.

13. Pantothenone Compound as defined in any one of the preceding claims for use in a method of treating or preventing malaria and/or infection by a protistan parasite of the genus Plasmodium, in a human subject in need thereof.

14. Pharmaceutical composition comprising a pantothenone compound as defined in any one of claims 1-12.

15. Pharmaceutical composition comprising a combination of a pantothenone compound and a pantothenamide compound.

16. Pharmaceutical composition comprising a combination of a pantothenone compound as defined in any one of claims 1-12 and a pantothenamide compound.

17. Pharmaceutical composition according to claim 15 or 16, wherein the pantothenamide compound is selected from the group represented by formula (III):

wherein

R⁵ represents hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide; R⁶ and R⁷ independently represent hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl;

X⁴ and X⁵ independently represent hydrogen or a group selected from hydroxyl, thiol, cyanide, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, sulfonamide, amide, pyrazole or imidazole;

X⁶ represents hydrogen or a group selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, each optionally substituted by hydroxyl, thiol, halogen and/or cyanide;

and pharmaceutically acceptable salts, esters, and prodrugs thereof.

18. Pharmaceutical composition according to claim 15-17, wherein the pantothenamide compound selected from the group of is selected from the group represented by formula (Ilia):

harmaceutically acceptable salts, esters, and prodrugs thereof.

19. Pharmaceutical composition according to any one of claims 15-18, wherein the pantothenamide compound is selected from the group represented by formula (Illb):

wherein R⁵ represents a group selected from alkyl, alkenyl or alkynyl;

and pharmaceutically acceptable salts, esters, and prodrugs thereof.

20. Pharmaceutical composition according to any one of claims 15-19, wherein the pantothenamide compound is selected from N5Pan, N7Pan and N9Pan:

and pharmaceutically acceptable salts, esters, and prodrugs thereof.

21. Composition according to any one of claims 15-20, comprising a combination of a pantothenone selected from RR2, RR6, RR7 and RR8 and a pantothenamide selected from N5Pan and N7Pan and pharmaceutically acceptable salts, esters and prodrugs of said compounds.

22. Composition according to any one of claims 14-21 for use in a method of treating or preventing malaria and/or infections by a protistan parasite of the genus Plasmodium in a human subject in need thereof.