GB2430621A - Benzopyranone derivatives as antiviral agents - Google Patents

Abstract

Use of a compound of formula (I): <EMI ID=1.1 HE=35 WI=92 LX=698 LY=711 TI=CF> <PC>wherein R<1>, R<2>, R<3>, R<4>, R<5>, R<6>, and R<7> are defined herein, and pharmaceutically acceptable salts thereof, in the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus. A pharmaceutical composition comprising compounds of formula (I) also forms part of the current specification.

Description

1TT0083 -1- 2430621 Benzopvranone derivatives as anti4raI a2ents This

invention relates to benzopyranone derivatives which act as inhibitors of viral polymerases, especially the hepatitis C virus (HCV) polymerase, and to uses of such compounds in the treatment and prevention of inibetion by hepatitis C virus.

The hepatitis C virus (HCV) is the major causative agent of parenterallytransniitted and sporadic non-A, non-B hepatitis (NANB-H). Some 1% of the human population of the planet is believed to be affected. Infection by the virus can result in chronic hepatitis and cirrhosis of the liver, and may lead to hepatocellular carcinoma. Currently no vaccine nor established therapy exists, although partial success has been achieved in a minority of cases by treatment with recombinant interferon-a, either alone or in combination with zibavirm. There is therefore a pressing need for new and broadly-effective therapeutics.

Several virally-encoded enzymes are putative targets for therapeutic intervention, including a metalloprotease (NS2-3), a serine protease (NS3) , a helicase (NS3), and an RNA-dcpendent RNA polymerase (NS5B). Of these, the polymerase plays an essential role in replication of the virus and is therefore an important target in the fight against hepatitis C. Certain benzopyranone derivatives have been disclosed in the art but none are disclosed as being useful as inhibitors of hepatitis C virus (HCV) polymerase. For instance, US patent application US2004/0087586 (Brueggemeier et a!) discloses 2-heterosubstituted 3-aryl-4H-benzopyran-4ones for the treatment of cancer, especially breast cancer: R{)1X_ R3 where X, R1, R2 and R3 are defined therein. US patent application US2004/0063665 (Bargiotti eta!.) discloses benzopyranone derivatives for the treatment of telomerase-modulated diseases, in particular cancer: o where R, R2, R, R, R5, R6, R7, R8, R9 and R10 are defined therein. However, neither of these disclosures relate to the treatment of hepatitis C virus infections.

1TT0083 - 2 - Surprisingly, it has now been found that certain benzopyranone derivatives act as inhibitors of the hepatitis C virus (1-ICV) polymerase enzyme.

Thus, in one aspect, there is provided the use of a compound of formula (I): R2-x.-. 0 it o R3 R OR7 (I) or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, wherein R', R3 and R6 are each independently selected from hydrogen, halogen, Ca1kyl, C2alkcnyl, C2. aikynyl and C38cycloalkyl; XisabondorO; R2 is hydrogen, C1 6alkyl, C2a1kenyl, C26alkynyl, C38cycloalkyl, (CH2)o3aryl or (CH2)0.3C(O)R8, optionally substituted by 1 to 8 halogen atoms, wherein R5 is hydrogen, NH2, N(C1.4aikyl)2, C,.6alkyl or C1alkoxy; R4 is hydrogen, C1 4kyl, C2alkeny1, C26alkynyl, C3cycloa1kyl, hydroxy, C1 6alkoxy or OC(O)H; R5 is hydrogen, C1 6alkyl, C26a&enyl, C2alkynyl, C38cycloalkyl, hydroxy, C1alkoxy or CF3; R7 is hydrogen, C1.6alkyl, C2.(,aikenyl, C25alkynyl or C38cycloalkyl.

In one embodiment of the present invention, R' is hydrogen or C1.6alkyl. Preferably R' is hydrogen or methyl.

In another embodiment, X is 0.

In another embodiment, R2 is hydrogen, Calkyl, (CH2)oaaryl or (CH2)0.3C(O) R8, optionally substituted by halogen, wherein R8 is as hereinbefore defined. Preferably, R2 is hydrogen, Calkyl, (CH2)o1phenyl or (CH2)01C(O)R8, optionally substituted by 1 to 8 fluorine, chlorine or bromine atoms, wherein R8 is hydrogen, NH2, C,aikyl or C, 4alkoxy. More preferably, R2 is hydrogen, C1aIkyl, benzyl or (CH2)01C(O) R8, optionally substituted by 1 to 3 chlorine atoms, wherein R8 is hydrogen, NH2, methyl or methoxy. Most preferably, R2 is hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, benzyl, chlorobenzyl, C(O)H, C(0) CH3, CH2C(O)N}12 or CH2CO2CH3.

When R2 is propyl, it may be n-propyl or i-propyl.

When R2 is butyl, it may be n-butyl, i-butyl or t-butyl, preferably nbutyl.

When R2 is hexyl, it may be straight-chain (n-hexyl) or branched, preferably straight-chain (n- hexyl).

When R2 is chlorobenzyl, it may be 2-, 3- or 4-chlorobenzyl, preferably 4chlorobenzyl.

1TT0083 - 3 - In another embodiment, R3 is hydrogen or C1a1ky1. Preferably, R3 is hydrogen, ethyl or propyl.

When R3 is propyl, it may be n-propyl or i-propyl, preferably n-propyl.

In another embodiment, R4 is hydrogen. C16a1ky1, hydroxy, C1 6alkoxy or OC(O)H. Preferably, R4 is hydrogen, hydroxy or OC(O)H.

In another embodiment, R5 is hydrogen, C,.6alkyI, hydroxy, C1 6alkoxy or CF3. Preferably, R5 is hydrogen, methyl, hydroxy or CF3.

In another embodiment, R6 is hydrogen or CI.(alkyl. Preferably R6 is hydrogen or methyl.

In another embodiment, R6 is at the 3- or 4-position of the furyl ring.

In another embodiment, R7 is hydrogen or C1aikyl. Preferably, R7 is C16alkyl. More preferably, R7 is C14ky1. Most preferably, R7 is methyl, ethyl, n-propyl or i-propyl.

In another embodiment, the furyl ring is attached to the benzopyranone moiety at the 3- or 4- position of the furyl ring.

In a furtheT embodiment of the present invention, there is provided the use of a compound of formula (Ia): (Ta) or a pharmaceutically acceptable salt thereof, for the manuftcture of a medicament for the fleaflnent or prevention of infection by hepatitis C virus, wherein R', R2, R3, R4, R5, R6 and R7 are as defined in relation to formula (I).

Preferably R' is hydrogen or C16alkyl. More preferably, R' is hydrogen or methyl Preferably, R2 is hydrogen, C1 4kyl, (CH2)03aay1 or (CH2)03C(O)R8, optionally substituted by 1 to 8 halogen atoms, wherein R8 is as defined in relation to formula (I). More preferably, R2 is hydrogen, C1alkyl, (CIT2)o. iphenyl or (CH2)0 1C(O)R8, optionally substituted by 1 to 8 fluorine, chlorine or bromine atoms, wherein R8 is NH2, C14alkyl or C14alkoxy. Most preferably, R2 is hydrogen, C1.6alkyl, benzyl or (CH2)ojC(O)R8, optionally substituted by I to 3 chlorine atoms, wherein is NIT2, methyl or methoxy.

Especially, R2 is hydrogen, methyl, n-propyl, i-propyl, n-butyl, n-hexyl, benzyl, 4-chlorobenzyl, CH2C(O)NH2, C(O)CH3 or CH2CO2CH3.

Preferably, It3 is hydrogen or C1,alkyl. More preferably, It3 is hydrogen or ethyl.

Preferably, R4 is hydrogen.

Preferably, It5 is hydrogen, C16alkyl or CF3. More preferably, R5 is hydrogen, methyl or CF3.

Preferably, It6 is hydrogen or C1a1kyl. More preferably, R6 is methyl.

Preferably, It7 is hydrogen or C,alkyl. More preferably, R7 is methyl.

1TT0083 -4 - In a further embodiment of the present invention, there is provided the use of a compound of formula (Ib): R2o)ç; or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C vinis, wherein R', R2, R3, R4, R5, R6 and R7 are as defined in relation to formula (I).

Preferably R' is hydrogen or C,.6alkyL More preferably, R1 is hydrogen.

Preferably, R2 is hydrogen, C16a1ky1 or (C112)()3C(O)Ri, where R8 is as defined in relation to formula (1). More preferably, R2 is hydrogen, methyl or C(O)H.

Preferably, R3 is hydrogen or C.aIkyl. More preferably, R3 is hydrogen or n-propyl.

Preferably, R4 is hydrogen, C16alkyl, hydroxy, C1alkoxy or OC(O)H. More preferably, R4 is hydrogen, hydroxy orOC(O)H.

Preferably, R5 is hydrogen, C16alkyl, hydroxy or C16allcoxy. More preferably, R5 is hydrogen, methyl or hydroxy.

Preferably, R6 is hydrogen or C14çalkyl. More preferably, it6 is hydrogen.

Preferably, R7 is hydrogen or C1a1kyl. More preferably, R7 is ethyl, npropyl or i-propyl.

When any variable occurs more than one time in formula (I) or in any substituent, its definition on each occurrence is independent of its definition at eveiy other occurrence.

As used herein, the term "alkyl" or "alkoxy" as a group or part of a group means that the group is straight or branched. Examples of suitable alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl and t-butyl. Examples of suitable alkoxy groups include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy and t-butoxy.

The cycloalkyl groups referred to herein may represent, for example, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

As used herein, the term "alkenyl" and "alkynyl" as a group or part of a group means that the group is straight or branched. Examples of suitable alkenyl groups include vinyl and allyl. Suitable alkynyl groups are ethynyl and propargyl.

When used herein, the term "halogen" means fluorine, chlorine, bromine and iodine.

When used herein, the term "aryl" as a group or part of a group means a carbocyclic aromatic ring. Examples of suitable aryl groups include phenyl and naphthyl.

Where a compound or group is described as "optionally substituted", one or more substituents may be present As appropriate an optional substituent may itself be substituted by another substituent.

1TF0083 - 5 - Specific compounds within the scope of this invention include those listed in Table 1 below and their pharmaceutically acceptable salts.

For use in medicine, the salts of the compounds of formula (1) will be non-toxic phannaccutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds according to the invention or of their non-toxic pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds of this invention include acid addition salts which may, for example, be formed by mixing a solution of the compound according to the invention with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, fumaric acid, p-toluenesulfonic acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid, phosphoric acid or sulfuric acid.

Salts of amine groups may also comprise quaternazy ammonium salts in which the amino nitrogen atom catries a suitable organic group such as an alkyl, alkenyl, alkynyl or aralkyl moiety. Furthermore, where the compounds of the invention carly an acidic moiety, suitable pharmaceutically acceptable salts thereof may include metal salts such as alkali metal salts, e.g. sodium or potassium salts; and alkaline earth metal salts, e.g. calcium or magnesium salts.

The salts may be formed by conventional means, such as by reacting the free base form of the product with one or more equivalents of the appropriate acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is removed in vacuo or by freeze diying or by exchanging the anions of an existing salt for another anion on a suitable ion exchange resin.

The present invention includes within its scope prodrugs of the compounds of formula (I) above.

In general, such prodrugs will be functional derivatives of the compounds of formula (I) which are readily convertible in vivo into the required compound of formula (I). Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in "Design of Prodrugs", ed.

H. Bundgaard, Elsevier, 1985.

A prodrug may be a pharmacoiogicaliy inactive derivative of a biologically active substance (the "parent drug" or "parent molecule") that requires transformation within the body in order to release the active drug, and that has improved delivery properties over the parent drug molecule. The transformation in vivo may be, for example, as the result of some metabolic process, such as chemical or enzymatic hydrolysis of a carboxylic, phosphoric or sulfate ester, or reduction or oxidation of a susceptible functionality.

The present invention includes within its scope solvates of the compounds of formula (I) and salts thereof, for example, hydrates.

The present invention also includes within its scope any enantiomers, diastereomers, geometric isomers and tautomers of the compounds of formula (1). It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the invention.

In another aspect of the invention, there is provided a method of inhibiting hepatitis C virus polymerase and/or of treating or preventing an illness due to hepatitis C virus, the method involving administering to a human or animal (preferably mammalian) subject suffering from the condition a 1TT0083 - 6 - therapeutically or prophylactically effective amount of the pharmaceutical composition described below or of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof.

"Effective amount" means an amount sufficient to cause a benefit to the subject or at least to cause a change in the subject's condition.

In a further embodiment of the present invention, there is provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the irealment or prevention of infection by hepatitis C virus, in combination with one or more other agents for the treatment of viral infections such as an antiviral agent, and/or an immunomodulatory agent such as a-, or yintferon, particularly a-interferon. Suitable antiviral agents include ribavirin and inhibitors of hepatitis C virus (HCV) polymerase, such as inhibitors of metalloprotease (NS2-3), serine protease (NS3), helicase (NS3) and RNA-dependent RNA polymerase (NS5B).

A further aspect of the invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable carrier. The composition may be in any suitable form, depending on the intended method of administration. It may for example be in the form of a tablet, capsule or liquid for oral administration, or of a solution or suspension for administration parenterally. The composition may be prepared by admixing at least one active ingredient, or a pharmaceutically acceptable salt thereof, with one or more pharmaceutically acceptable adjuvants, diluents or carriers and/or with one or more other therapeutically or prophylactically active agents.

The dosage rate at which the compound is administered will depend on a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age of the patient, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition and the host undergoing therapy. For the treatment or prevention of infection by hepatitis C virus, suitable dosage levels may be of the order of 0.02 to 5 or lOg per day, with oral dosages two to five times higher. For instance, nilministration of from 10 to 50mg of the compound per kg of body weight from one to three times per day may be in order. Appropriate values are selectable by routine testing. The compound may be administered alone or in combination with other treatments, either simultaneously or sequentially. For instance, it may be administered in combination with effective amounts of antiviral agents, immunomodulators, anti-infectives or vaccines known to those of ordinaiy skill in the art. It may be administered by any suitable mute, including orally, intravenously, cutaneously and subcutaneously. It maybeadministereddirectlytoasuitablesitcorinamannerinwhichittargetsapartic ularsite,suchasa certain type of cell. Suitable targeting methods are already known.

Compounds of general formula (1) may be obtained commercially or prepared by methods known in the art of organic synthesis.

ff10083 - 7 - It will be understood that any compound of formula (1) initially obtained commercially may, where appropriate, subsequently be elaborated into a further compound of formula (I) by techniques known from the art.

For instance, a compound of formula (1) where R7 is methyl may be transformed into a compound of formula (I) whore R7 is hydrogen by saponification by, for example, acid or alkaline hydrolysis.

Where a mixture of products is obtained from any of the processes described above for the preparation of compounds according to the invention, the desired product can be separated therefrom at an appropriate stage by conventional methods such as preparative HPLC; or column chromatography utilising, for example, silica and/or alumina in conjunction with an appropriate solvent system.

During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Cheinisty, ed.

J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene & P.G.M. Wuts, Protective Groups in O,anic Synthesis, John Wiley & Sons, 3rd edition, 1999. The protecting groups may be removed at a convenient subsequent stage using methods known from the art.

The compounds of the invention were tested for inhibitory activity against the HCV RNA dependent RNA polymerase (NS5B) in an enzyme inhibition assay (example i)) and in a cell based sub- genomic replication assay (example ii)). The compounds generally have 1C50's below 100.tM in the enzyme assay and several examples have EC5O's below 25 iM in the cell based assay.

I) Enzyme purification assay HCV NS5B2l polymerases with C-terminal His6 tags were expressed in E. co/i BL2I(DE3). Cells wore grown to mid-log phase at 37 C in 10 L Luria-Bertani broth with 100 p.gfmL ampicillin. The temperature of the incubator was then reduced to 18 C and IPTG (1 mM final) was added to induce expression. Induction proceeded for 18 bra. Cells were collected by centrifugation, and the pellets stored at -70 C until use.

Cell pellets were resuspended on ice with.-50mLs of lysis buffer (20mM Tris-HC1 pH 7.5, 10% glycerol, 0.5M KCI, 5mM MgCl2, 2mM f-mercaptoethanol (ME), 0.2% n- octytglucoside, 20 tablets Complete EDTA-Free Protease Inhibitors per L (Roche Diagnostics Corp.). DNAase 1(5000 units grade I from Roche) was added and the mixture was incubated on ice for 10 minutes with gentle stirring. The suspension was Dounce homogenized then passed three times through a Microfluidizer model I IOY (Microfluidics Corporation) at 4 C. The lysate was clarified by centrifugation at 15,000rpm at 4 C for 30 minutes in a JA-17 rotor (Beckman Coulter). The collective supernatant was incubated using gentle agitation for 1 hour at 4 C with 5mLs TALONS CellThru resin (Clontech) that was equilibrated with equilibration/wash buffer (20mM Tris, pH 7.5, 10% glycerol, 0.5M KCI, 2mM BME, 0.2% n-octyl glucoside). The resin- lysate suspension was centrifuged at 200arg for 5 minutes to pellet the resin, which was then washed with 5 column 1TT0083 - 8 - volumes of equilibration/wash buffer (20mM Tris-HC1 pH 7.5, 10% glycerol, 0.5M KC1, 2mM fME, 0.2% n-octylglucoside) for 10 minutes at 4 C. The resin was collected by centrifugation at 2000xg for 2 minutes, and washed an additional four times. Protein was eluted from the resin by the addition of one column volume of elution buffer (20mM Tris-HC1 pH 7.5, 10% glycerol, 0.5M KCI, 2mM J3ME, 0.2% n-octylglucoside, 200mM imidazole) with gentle agitation for 30 minutes at 4 C.

The eluate containing the eluted protein was separated from the resin by centrifugation at 2000xg for 2 minutes. The elution procedure was repeated two more times. The eluates were dialyzed (20mM Tris-HC1 pH 7.5, 10% glycerol, 0.25 or 0.5M KCI, 3mM D'VF, 0.2% n-octylglucoside) at 4 C.

Protein concentrations were determined using Coomassie Plus Protein reagent (Pierce), and the dialyzed eluates were aliquoted, quick frozen on dry ice and stored at -70 C. Protein visualization was performed using 4-15% gradient Tris-Glycine SDS PAGE gels (Invitrogen) and GelCode Blue Stain Reagent (Pierce). The purified HCV NS5B21(His6 tag) proteins were > 80% homogeneous.

ii) In-vitro HCV NS5B Enzyme Inhibition Assay FICV RNA polymerase activity was measured by following the incorporation of tritiated UMP into a primer-template composed ofbiotinylated-oligodT16 annealed to poly(ribo-adenosine) in a scintillation proximity assay (SPA) format The standard reaction (100 j.tL) was carried out in a buffer containing 20mM IRIS, pH 7.5, 5OiiM EDTA, 2mM MgCI2, 10mM KC1, 0.0 1% Triton-Xl00, 5.52 mM DTF and 0.044 units/mL RNAsin (Promega). Reactions consisted of SFLl DMSOfLnhibitor and 75i1 l33nM NS5B-21 [lOOnM final] in reaction buffer which were incubated for! hour at room temperature.

To that were added!Oj.tl 200nM PolyrAl800nM BiodTl6 [2OnM PolyrAJ8OnM BiodTl6 final], and further incubated for 1 hour at 30 C. Then, lOil 0.1 17iCi4tl 3H UTP [O.Oll7iiCi4tl final]! 15j.tM cold UTP [!.5tM final] were added and reaction proceeded for 50 mm at 30 C. Then, !01.d reaction were removed and added to a shallow 384 well quench plate containing l0l 4mg/nil streptavidin SPA beads (Amcrsham RPNQ0007) in 0.5M EDTA. The plate was then read in a Topcount instninient.

Canying out this reaction in the presence of various concentrations of each compound set out above allowed determination of IC50 values by utilising the formula % Residual activity = IOO/(l+[lI/1C50)s where [1] is the inhibitor concentration and "s" is the slope of the inhibition curve.

lii) Cell based HCV Replication Assay Cell clones that stably maintain subgenomic HCV replicon were obtained by transfecting Huh-7 cells with an RNA replicon identical to 1377neo!NS3-3'/wt described by Lohmann et a!. (1999) (EMBL- genbank No. AJ242652), followed by selection with neomycin sulfute (G4!8). Viral replication was monitored by measuring the expression of the NS3 protein by an ELISA assay performed directly on cells 1TT0083 -9 - grown in 96 wells microtiter plates (Cell-ELISA) using the anti-NS3 monoclonal antibody 10E5/24 (as described in published International patent application WO 02/59321). Cells were seeded into 96 well plates at a density of i04 cells per well in a final volume of 0.1 ml of DMEMJ1O% FCS. Two hours after plating, 50 j.d of DMEM/10% FCS containing a 3x concentration of inhibitor were added, cells were incubated for 96 hours and then fixed for 10' with ice-cold isopropanol. Each condition was tested in duplicate and average absorbance values were used for calculations. The cells were washed twice with PBS, blocked with 5% non- fat dry milk in PBS + 0.1% Triton X100 + 0.02% SDS (PBSTS) and then incubated 0/n at 4 C with the 10E5/24 mab diluted in MiIkIPBSTS. After washing 5 times with PBSTS, the cells were incubated for 3 hours at room temperature with Fc specific anti-mouse IgG conjugated to alkaline phosphatase (Sigma), diluted in MiIk/PBSTS. After washing again as above, the reaction was developed with p-Nitrophenyl phosphate disodium substrate (Sigma) and the absorbance at 405/620 nm read at intervals. For calculations, we used data sets where samples incubated without inhibitors had absorbance values comprised between 1 and 1.5. The inhibitor conceniration that reduced by 50% the expression of NS3 (IC50) was calculated by fitting the data to the Hill equation, Fraction inhibition = 1-(Ai-b)/(A0-b) = [J]0 / ([I]' + IC50) where: - Ai = absorbance value of IIBI1O cells supplemented with the indicated inhibitor concentration.

- A0 = absorbance value of HBI 10 cells incubated without inhibitor.

- b = absorbance value of Huh-7 cells plated at the same density in the same microtiter plates and incubated without inhibitor.

- n = Hill coefficient.

The following Examples are illustrative of the invention.

Table 1

Example Structure Name Source no. ______________________________ ________________________________ 1 F F methyl 4-[7-(2-amino-2-oxoethoxy)-8- A o - i F methyl-4-oxo-2-(trifluoromethyl)-4H- chromcn-3-yl]-5-methyl-2-furoate 0 00 2 HO 0 0 ethyl 5-(7-hydroxy-2-oxo-2H- B - o o chromen-3-yl)-2-furoate 3, ...- ethyl 5-(7-methoxy-4-oxo-6-propyl- C 4H-chromen-3-yl)-2-furoate 1TT0083 -10- oxo-4H-cbromcn-3-yl)-5-methyl-2- methyl 4-(7-hydroxy-2,8-diniethyl-4- A furoate propyl 5-(7-methoxy-2methyl-4-oxo- A 4H-chromen-3-yl)-2-furoate _______ 5) _________________________ ______ F F methyl 4-[7-butoxy-8- methyl-4-oxo-2A 6 (ixifluoromethyl)-4H-chromen-3-ylJ-5- methyl-2-furoate 4-oxo-4H-chromen-3-yl]-5-methyl-2- methyl 4-[7-(acetyloxy)-2,8-dimethyl- A furoate 2.{irifluoromethyl)-4H-chromen-3-yl]- 8 HO)J( methyl 4-[7-hydroxy-8-methyl-4-oxo- A 5-methyl-2-furoate 0/ methyl 4-[7-(2-methoxy-2-oxoethoxy)- A 8-methyl-4-oxo-2-(lrifluoromethyl)4H-chromen-3-yl]-5-methyl-2-furoate methyl-4-oxo-2-(tiifluoromethyl)-4Hmethyl 4-[7-(2-ammo-2-oxoethoxy)-8- A chromen-3-yl]-5-methyl-2-furoate isopropyl 5-(7-methoxy-2-methyl-4- A oxo-4H-chromen-3-yl)-2-furoate 12 HO, . 0 ethyl 5-(5,7-dihydroxy-4-oxo-4H- A chromen-3-yl)-2-furoate ____ o a _______________ ____ 2-(lrifluoroniethyl)-4H-chromen-3-yl}5-methyl-2-furoate 13 methyl 4-[7-methoxy-8-methyl-4-oxo- A 0/ F F methyl 4-[7-(hexyloxy)-8- methyl-4- A 14 OYLT...O.kçO oxo-2-(lrifluoromethyl)-4H-chromen- 3-yl]-5-methyl-2-furoate fF10083 -11propoxy-2-(trifluoromethyl)-4H- methyl 5-methyl-4-[8-methyl-4-oxo-7- A chromen-3-yl]-2-furoate o / methyl-4-oxo-2-(lrifluoromethyl)-4H- 16 methyl 4-[7-[(4-chlorobenzyl)oxy]-8- A chromen-3-yI]-5-methyl-2- furoate o i oxo-2-(lrifluoromethyl)-4H-cbromen- 17 methyl 4-[7-(benzyloxy)-8-methyl-4A 3-yl]-5-methyl-2-furoate 18 HO o ethyl 5-(7-hydroxy-4-oxo-4H- A "CLLo oJ chromen-3-yl)-2-furoate 19 ethyl 5-[5,7-bis(forinyloxy)-4-oxo-4H- A chromen-3-yl]-2-furoate ri _______ p _____________________________ _______ methyl 4-(7-butoxy-8- methyl-4-oxo- A 4H-chromen-3-yl)-5-methyl-2-furoate o 0 methyl 4-(7-hydroxy-8-methyl-4- oxo- A 4H-chromen-3-yl)-5-methyl-2-furoate 21 HOO) g,jL0' ooxo-4H-chromen-3-yl]-5-mcthyl-2- 22 methyl 4-[7-(tyloxy)-8-methyl-4- A 0 furoate ___ 0,0 ___________ __ oxo-4H-chromen-3-yl]-5-methyl-2- furoate 23 methyl 4-[7-(acetyloxy)-8-methyl-4- A 24 I methyl 4-(6-ethyl-7-methoxy-4-oxo- A 0 0 4H-chromen-3-yl)-5-methyl-2-furoate 1TT0083 -12- CL3 methyl 4-{7-[(4-cblorobenzyl)oxy]-6- A methyl-2-furoate cthyl-4-oxo-4H-cbromen-3-yl} -5- ___ O/0 $) _____________ ___ methyl 4{7-[(4-chlorobenzyl)oxy]-6- A 26 O, , 0 ethyl-4-oxo-4H-chromen-3-yl) -5methyl-2-furoate 27 CIL. methyl 4-{7-[(4-cblorobenzyl)oxy]-6- A thyl-2-methyl-4-oxo-4H-chromen-3- yl}-5-methyl-2-fimate 28 HO / 0 0 methyl 4-(7-hydroxy-4-oxo-4H- D chromen-3-yl)-5-methyl-2- furOate 0 chromen-3-yl]-5-methyl-2-furoatc 29 methyl 4-[7-(acelyloxy)-4-oxo-4H- D ___ 0)) ___________ ___ methyl 5-methyl-4-(2-methyl-4-oxo-7- D 0 propoxy-4H-chronien-3-yl)-2-furoate o oxo-4H-chromen-3-yl)-5-methyl-2- 31 _0}[J1> methyl 4-(7-isopropoxy-2-methyl-4- D furoate methyl 4-(7hydroxy-2-methyl-4-oxo- D 32 HO 0 4H-chromcn-3-yI)-5-methyl-2-furoatc methyl 4-[7-(acetyloxy)-2-methyl-4- D oxo-4H-chromen-3-yl]-5-methyl-2- 0/ 0 0 furoate 34 methyl 4-(7-methoxy-2-methyl-4-oxo- D 0 4H-chromen-3-yl)-5-methyl-2-furoate ___ 07-0,0 ____________ ___ Sources A: AvitaWayn, Lawrenceville, NJ 08648, USA B: Aldrich (USA) C: Interbioscreen Ltd., Moscow, Russia D: Enamine, Kiev, Ukraine

Claims (10)

1. fF10083 -13- Claims 1. The use of a compound of formula (I): i-x o o R3 R

   OR7 (I) or a pharmaceutically acceptable salt thereof, for the manufacture of a meclicament for the trealment or prevention of infection by hepatitis C virus, wherein R1, R3 and R6 are each independently selected from hydrogen, halogen, Calky1, C2aIkenyl, C2(alkynyl and C38cycloalkyl; XisabondorO; R2 is hydrogen, C1,aIlcy1, C2aIkeny1, C26aIkynyl, C38cycloalkyl, (CH2)o.3aryl or (CH2)o3C(O)R8, optionally substituted by 1 to 8 halogen atoms, wherein R is hydrogen, NI-I2, N(C1alkyl)2, Calkyl or C3a1koxy; R4 is hydrogen, C14ky1, C24a]kenyl, C2aikyny1, C34cycloalkyl, hydroxy, C1 alkoxy or OC(O)H; R is hydrogen, C16a1ky1, C26alkenyl, C2a1kynyl, C38cycloalkyl, hydroxy, C1,alkoxy or CF3; R7 is hydrogen, C1 alkyl, C26alkenyl, C26alkynyl or C33cycloaIkyl.
2. 2. The use of a compound of formula (I) according to Claim 1, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, wherein R' is hydrogen or C,aIkyl.
3. 3. The use of a compound of formula (1) according to Claim 1 or Claim 2, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, wherein X is 0.
4. 4. The use of a compound of formula (I) according to any one of Claims 1 to 3, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, wherein R2 is hydrogen, C16alkyl, (CH2)o3aryl or (CH,)03C(O)R8, optionally substituted by halogen, wherein R8 is as defined in Claim 1.

   1TT0083 -14-
5. 5. The use of a compound according to Claim 1 of formula (Ia): R3 0 (Ia) R4 R60 0 or a pharmaceutically acceptable salt thereof, for the manufacture of a medicanient for the treatment or prevention of infection by hepatitis C virus, wherein R', R2, R3, R4, R5, R6 and R7 are as defined in Claim 1.
6. 6. The use of a compound according to Claim 1 of formula (Ib): R2o))ç or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, wherein R', R2, R3, R4, R5, R6 and R7 are as defined in Claim 1.
7. 7. The use of a compound according to Claim I selected from: methyl furoate, ethyl 5(7hydroxy-2-oxo-2H-chromen-3-yl)-2-fUrOate, ethyl 5(7methoxy4oxo6-propyl-4H-ChrOfliefl-3.Yl)-2-fUroate, methyl 4.(7hydroxy2, 8dimethyl4_oxo-4H-Chromefl-3-Yl)-5-methYl24W0ate, propyl methyl methyl methyl methyl 2-furoate, methyl fliroate, 1TT0083 -15- isopropyl 5-(7-methoxy-2-methyl-4-oxo-4H-chromen-3-yl)-2-furoate, ethyl 5(5,7-dihydroxy-4-oxo-4H-chromen-3-yl)-2-furoate, methyl 4-[7-methoxy-8methyl4-oxo-2fluoromethyl)-4H-chromen-3-ylj-5-methyl-2-furoate, methyl 4[7-(hexyloxy)-8-methyl-4-oxo-2-(irifluoromethyl)-4H-chromen-3-yl]-5methyl-2-furoate, methyl 5-me hyl-4-[8-methyl-4-oxo-7-propoxy-2(irifluoromethyl)-4H-chromen-3-yl]-2-furoate, methyl 4-[7-[(4-chlorobenzyl)oxy]-8-methyl-4-oxo-2-(trifluoromethyl)-4Hchromen-3-yl]-5-methyl-2- furoate, methyl 4-[7-(benzyloxy)-8-niethyl-4-oxo-2-(trifluoromethyl)-4Hchromcn-3-yl]-5-methyl-2-furoate, ethyl 5-(7-hydroxy-4-oxo-4H-chromen-3yl)-2-furoate, ethyl 5-[5,7-bis(formyloxy)-4-oxo-4H-chromen-3-yl]-2furoate, methyl 4-(7-butoxy-8-methyl-4-oxo-4H-chromen-3-yI)-5-methyl-2furoate, methyl 4-(7-hydroxy-8-methyl-4-oxo-4H-chromen-3-yl)-5-methyl-2furoate, methyl 4-[7-(acetyloxy)-8-methyl-4-oxo-4H-chromen-3-yl]-5-methyl2-furoate, methyl 4-[7-(acetyloxy)-8-methyl-4-oxo-4H-chromen-3-yl]-5methyl-2-furoate, methyl 4-(6-ethyl-7-methoxy-4-oxo-4H-chromen-3-yl)-5methyl-2-furoate, methyl 4- {7-[(4-chlorobenzyl)oxy]-6-ethyl-4-oxo-4Hchromen-3-yl}-5-methyl-2-furoate, methyl 4- (7-[(4-chlorobenzyl)oxy]-6cthyl-4-oxo-4H-chromen-3-yl}-5-methyl-2-furoate, methyl 4- {7-[(4. chlorobenzyl)oxy]-6-ethyl-2-methyl-4-oxo-4H-chromen-3-yl) -5-methyl-2f1roate, methyl 4-7-hydroxy-4xo-4H-chromen-3-yl)-5-methyl-2-furoate, methyl 4-[7-(acetyloxy)-4-oxo-4H-chromen-3-yl]-5-methyl-2-furoate, methyl 5-methyl-4-(2-methyl-4-oxo-7-propoxy-4H-chromen-3-yl)-2-furoate, methyl 4(7-isopropoxy-2-methyl-4-oxo.4H-chromen-3-yl)-5-methyl-2-furoate, methyl 4-(7-hydroxy-2-methyl-4-oxo-4H-chromen-3-yl)-5-methyl-2-furoate, methyl 4[7-(acetyloxy)-2-methyl-4-oxo.4H-chromen-3-yl]-5-methyl-2-furoate, methyl 4-(7-methoxy-2-methyl-4-oxo-4H-chromen-3-yl)-5-methyl-2-furoate, or a pharmaceutically acceptable salt thereof; for the manu1cture of a medicament for the treatment or prevention of infection by hepatitis C virus.
8. 8. A method of inhibiting hepatitis C virus polymerase and/or of treating or preventing an illness due to hepatitis C virus, the method involving a4niinistering to a human or animal subject suffering from the condition a therapeutically or prophylactically effective amount of a compound according to any one of Claims 1 to 7, or a pharmaceutically acceptable salt thereof.
9. 9. The use of a compound according to any one of Claims 1 to 7, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment or prevention of infection by hepatitis C virus, in combination with one or more other agents for the trealment of viral infections such as an ITTOOS3 -16- antiviral agent, and/or an immunomodulatory agent such as a-, - or y- interferon, particularly ainterferon.
10. 10. A phannaceutical composition comprising a compound according to any one of Claims 1 to 7 or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable carrier.