WO2013090840A1 - 2 -amino- pyrido [3, 2 -d] pyrimidine derivatives as hcv inhibitors - Google Patents

Abstract

A compound of Formula I : or a pharmaceutically acceptable salt thereof, wherein the substituents are described herein, methods of making the compounds as well as compounds of formula (I) for use in the treatment of HCV infection.

Description

2 -AMINO- PYRIDO [3 , 2 -D] PYRIMIDINE DERIVATIVES AS HCV INHIBITORS

FIELD OF THE INVENTION

The present application includes novel inhibitors of HCV, compositions containing such compounds, therapeutic methods that include the administration of such compounds.

BAC GROUND OF THE INVENTION

Hepatitis is a disease occurring throughout the world. Hepatitis Is generally of viral nature, although there are other known causes. Viral hepatitis is by far the most common form of hepatitis. In the U.S. nearly 750,000 are affected by hepatitis each year, and out of those, more than 150,000 are Infected with the hepatitis C virus ("HCV"). HCV is a positive-stranded RNA virus belonging to the Flaviviridae family and has closest relationship to the pestiviruses that include hog cholera virus and bovine viral diarrhea virus (BVDV).

HCV Is believed to replicate through the production of a complementary negative-strand RNA template. The HCV genome is a single-stranded, positive- sense RNA of about 9,600 bp coding for a poiyprotein of 3009-3030 amino-acids, which is cleaved co- and post-translationally by cellular and two viral proteinases into mature viral proteins (core, E1 , E2, p7, NS2, NS3, NS4A, NS4B, NS5A, NS5B). The structural proteins, E1 and E2, are believed to be embedded into a viral lipid envelope and form stable beterodlmers. The structural core protein Is believed to interact with the viral RNA genome to form the nueleocapstd. The nonstructural proteins designated NS2 to NS5 include proteins with enzymatic functions involved in virus replication and protein processing including a polymerase, protease, and helicase.

The main source of contamination with HCV is blood. The magnitude of the HCV infection as a health problem is illustrated by the prevalence among high-risk groups. For example, 60% to 90% of hemophiliacs and more than 80% of

■ntravenous drug abusers in western countries are chronically infected with HCV. For intravenous drug abusers, the prevalence varies from about 28% to 70% depending on the population studied. The proportion of new HCV Infections associated with post-transfusion has been markedly reduced lately due to advances in diagnostic tools used to screen blood donors. One available treatment for HCV infection is interferon-a (fFN-a). According to different c!inical studies, however, only 70% of treated patients normalize alanine aminotransferase (ALT) levels in he serum and after discontinuation of I FN, 35% to 45% of these responders relapse. In general, only 20% to 25% of patients have long-term responses to IFN. Clinical studies have shown that combination treatmen with IFN and ribavirin (RIBA) results in a superior clinical response than IFN alone. Different genotypes of HCV respond differently to IFN therapy; genotype 1 is more resistant to IFN therapy than types 2 and 3.

HCV is currently classified into eleven major genotypes (designated 1-11 ), many subtypes (designated a, b, c, and so on), and about 100 different strains (numbered 1 ,2,3, and so on) based on the genomic sequence heterogeneity.

Genotypes 1 , 2 and 3 are distributed worldwide. Types 1a and ib are the most common, accounting for about 60% of global infections. Types 1a and l b predominate In Northern Europe and North America, and in Southern and Eastern Europe and Japan, respectively. Type 2 Is less frequently represented than type 1. Type 3 is endemic in south-east Asia and is variably distributed in different couniries Genotype 4 is principally found in the Middle East, Egypt, and central Africa, Type 5 is almost exclusively found in South Africa, and genotypes 6- 1 are distributed in Asia

it would foe useful, therefore, to provide a compound that is effective against more than a single HCV genotype.

SUMMARY OF THE INVENTION

There have now been discovered new antiviral compounds that are effective against not only genotype 1a HCV, but other genotypes as well.

In one embodiment of the present invention, there Is provided a compound of ■rmula i:

or a pharmaceutically acceptable salt thereof, wherein:

R¹ is (d - Cs) alkyl, O ~ (d - C₆) aikyl, NR⁹R' ,

R² is C(0)NR¹¹R¹² , C{0)R¹³, 5 membered heterocycle, or

5 membered heteroaryl,

where X is O or S,

R³ is H, (d - C₃) alkyl,

R⁴ is (C - C₈) .aikyl, either unsubstituted or substituted with halo,

R⁹ is H, (C;^■·^■■ C₄) aiky!, said (Ci - C ) alky) being unsusbstituted or substituted with one

or more halo, or

R¹⁰ is H, (Ci - C₄) alkyl, said ( - C₄) aikyl being unsusbstituted or substituted with one

or more halo, or R⁹ and R ⁰, together with the nitrogen atom to which they are attached, form a 4 or 5 membered nitrogen containing heterocycle, said 4 or 5 membered nitrogen containing heterocycle being unsubstituted or substituted with one or more halo,

R^{1 i} is H, (Ci "^■ C₄) alkyl, {Ci - C₄) haloa!kyi, 5-8 membered heterocycle or

5-6 membered heteroaryl;

R'² is H , (Ci ~ C ) aikyl or (d - C₄) haloalkyl; or

R¹¹ and R¹², together with the nitrogen atom to which they are attached, form a

5 or 6 membered nitrogen containing heterocycle, said 5 or 8 membered nitrogen containing heterocycle being unsubstiiuted R¹³ is OH, 0-(d - C₄) alkyl,

R^:': is NR^'I6R^'6

R¹⁵ is H, (C, - C₆) aikyl, (d - C₆) haioalkyl, 4-7 membered heterocycle, 5-6 membered heteroaryf, 3-7 membered cycloalkyi, and wherein each of said 4-7 membered heterocyc!e, 5-6 membered heteroaryl, 3-7 membered cycloalkyi is unsubstiiuted or substituted at a substi utab!e position with one or more ~0, OH, (Ci - Cs) alkyi, (d ·^■■■ C₆) haioaikyi, (d - C₆) aikoxy, amino, or , {d - 0₆) aminoa!ky!; and

R^ib is H, (d - C₆) alkyi, or (d - C₆) haioaikyi;

provided that when one of ¹⁵ or R¹⁶ is H, the other is not H.

In some embodiments of Formula I, R² is a 5 membered heteroaryl. n some embodiments of Formula I in which , R" is a 5 membered

heteroaryl, R² is , and X is O, NH, CH, or S,

In other embodiments of Formula L R² is C(0)NR¹¹R¹². in some embodiments of Formula I, R is (d - C₆) alkyi, either unsubsistuied or

substituted with halo, (Ci ~ C₆) aikoxy, or (d - Cg) haloaikoxy.

In some embodiments of Formula I, R is (Ci ·^■■■ C₈) alkyi, (C -C₈) haioaikyi, amino, or (C Cg) haloaikoxy.

In another embodiment of the present invention, there is provided a compound of Formula ii:

or a pharmaceutically acceptable salt thereof, wherein:

R¹ is {Ci^■■■ C₆) alkyi, O ~ (C, - C₆) alkyi, O ~ (d - C₆) haioaikyi, NR⁹R¹⁰, Halo,

(C C₈) alkenyl, C¾-C₈) alkynyl, (d -d) haioaikyi, O - (d^■■■ C₆) haioaikyi, (C₂~ C₆) ha!oaikenyl, (C₂-C₆) hafoalkyny!, (d-C₃)aikoxy, or (d-Ce) haioalkoxy,; R³ is H, (Ci - C_e) alkyl (C₂-C₆)alkeny!, (C₂-C₆)alkynyi, (C C₃)aikoxy_> amino, or {Ci-C₃)haloaikyi;

R³ is H, (C₁ - Ce) alkyl, (C₂-C₆)aikenyi, (C₂-C₆)a!kynyl, (C_rC₃}alkoxy, amino, or (C C₃)haloa!kyl;

R⁴ is H, (Ci ~ Ce) a!kyi, either unsubstituted or substituted with halo, (d - C₆) aikoxy, S{0), S(0)_2> S(0)CH₃, S(0)₂CH₃, C(0)R⁶, C(0)OR⁷ or (C₃-C₆)cyc!oa!kyi, said (C₃-C₆)cycloaikyl being unsusbsiituted or substituted with one or more halo, amino, {d -^■ C₆) a!kyS, or (C Cs) haloalkyl

R⁶ is id ~ C₆) aikyi, either unsubstituted or substituted with halo, or NR^{21 22}; and R⁶ is H, (d - C₆) aikyi, either unsubstituted or substituted with halo, or NR²³R^2Z; or

R^b and R⁶, together with the nitrogen atom to which they are attached, form a

5 or 8 membered nitrogen containing heterocycie, said 5 or 6 mernbered nitrogen containing heterocycie being unsubstituted or substituted with OH, halo, -O, or (d - C_e) aikyi. in other embodiments of the instant invention, there Is provided a compound of Formula III:

or a pharmaceutically acceptable sail thereof, wherein:

X is 0 or S;

R ' is (d - C_s) aikyi, O - (C, ~ C₆) alkyl, O - (d - C₆) haloalkyl, NR⁹Rⁱ⁰, Halo, (C₂~ C₈)

a!kenyi, C₂-C₈) aikynyl, {C C₆) haloalkyl, O - (C _: - C₆) haloalkyl, (C₂-C₆) haloalkenyi, (C₂-C₆) haloa!kyny!, {CrC_s)aikoxy, or (C C₆} haioaikoxy,;

R³ is H, (C₁ - C₆) aikyi, (Cs-C^alkenyi (C₂-C₆)alkyny!, (d-C₃)aikoxy, amino, or

(C_rC₃)haioalkyf;

R⁴ is H, (C-_t - Ce) alkyl, either unsubstituted or substituted with halo, (d - C₆) aikoxy, ^■3(0), S(0)₂, S(0)CH₃, S(0)₂CH₃₎ C(0)R⁶, C{0)OR⁷ or (C3-C₆)cycioaSkyi, said (C₃-C6)cyctoaikyi being unsusbstituted or substituted with one or more halo, amino, (d - C₆) aikyl, or {C C₆) hatoa!kyi;

R⁶ is H, (d - C₆) a!kyi or (d - C₆) haioaikyl;

R' is H, (Ci - C₆) aikyl or (C-, - C₆) haloaikyl;

R⁹ is H, (Ci - C₄) a kyl, said (Ci - C₄) aikyl being unsubstituted or substituted with one

or more halo; and

R¹⁰ is H, (C-i - C₄) alky!, said {Ci - C4) aikyl being unsusbstituted or substituted with one

or more halo, or R⁹ and R^s0, together with the nitrogen atom to which they are attached, form a 4 or 5 membered nitrogen containing heterocycie, said 4 or 5 membered nitrogen containing heterocycie being unsubstituted or substituted with one or more halo.

In another embodiment of the present invention, there is provided a pharmaceutical composition comprising a compound of Formula i, or a

pharmaceutically acceptable salt thereof , and a pharmaceutically acceptable carrier.

In another embodiment of the present invention, there is provided a method of treating HCV in a patient in need thereof, comprising administering to the patient a compound of formula I, or a pharmaceutscaiiy acceptable salt thereof.

In another embodiment of the present Invention, there is provided the use of a compound of any of Formulae I, II or III, or any compound exemplified herein, for treating HCV.

In another embodiment of the present invention, there is provided the use of a compound of any of Formulae I, H or i ll, or any compound exemplified herein for the manufacture of a medicament for treating HCV.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to certain embodiments of the invention, examples of which are illustrated in the accompanying description, structures and formulas. While the invention will be described in conjunction with the enumerated embodiments, 11 will be understood that they are not Intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover all aiternatives, modifications, and equivalents, which may be included within the scope of the present Invention.

Definitions

The term "alkyl," either alone or in combination with another term, means a saturated straight or branched chain hydrocarbon, including without limitation, methyl, ethyl, ^-propyl, Isopropyl, n-buiy!, isobutyi, sec-butyl, fert-buiyl, o-pentyl, and the like.

When the term "alkyl" is preceded with a carbon limitation, it is to be understood that the limitation applies to the numbe of carbons in the hydrocarbon chain. For example, the term (Ci - C₄) alkyl includes methyl, ethyl, propyl, n-butyl, isobutyi (or methylpropyi), sec-butyl and iert-butyi.

"Alkenyf is a hydrocarbon containing normal, secondary, tertiary, or cyclic carbon atoms with at least one site of unsafuratson, i.e. a carbon- carbon, sp2 double bond. For example, an alkenyi group can have 2 to 20 carbon atoms (i.e., C -C o alkenyi). 2 to 12 carbon atoms (i.e., C2-C12 alkenyi), or 2 to 6 carbon atoms (i.e., Cz~C& alkenyi). Examples of suitable alkenyi groups include, but are not limited to, ethylene, vinyl (-CH-CHa), ai!yl

{~ΟΗ₂ΟΗ=£Ή₂)₁ cycSopenfenyi (-C-sH?), and 5-hexenyl

(-CHaCHsCHjCHzCH-CHa).

"Alkynyl" is a hydrocarbon containing normal, secondary, tertiary or cyclic carbon atoms with at least one site of unsaturation, i.e. a carbon- carbon, sp triple bond. For example, an alkynyl group can have 2 to 20 carbon atoms (i.e., C2-C20 alkynyl), 2 to 12 carbon atoms (i.e., C2-C12 alkyne,), or 2 to 6 carbon atoms (i.e., C C-e alkynyl). Examples of suitable alkynyl groups include, but are not limited to, acetyienic (-C-CH), propargyl

(-CH2C-CH), , propyne, 2- butyne, and 1-3 butadiyne and the like. "Alkylene" refers to a saturated, branched or straight chain or cyclic hydrocarbon radical having two monovalent radical centers derived by the removal of tvvo hydrogen atoms from the same or tvvo different carbon atoms of a parent aikane. For example, an alkylene group can have 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 8 carbon atoms. Typical alkylene radicals include, but are not limited to, methylene {-CH₂-), 1 ,1 -ethylene (-CH{CH₃)-)₍ 1 ,2- ethylene (-CH₂CH₂~), 1 ,1 -propylene {-CH(CH₂CH₃R 1 ,2-propylene

(-CH₂CH(CH₃R 1 ,3-propylene (-CH₂CH₂CH₂-), 1 ,4-butylene

(-CH2CH2CH2CH2-), and the like.

"Aikenylene" refers to an unsaturated, branched or straight chain or cyclic hydrocarbon radical having tvvo monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkene. For example, and aikenylene group can have 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 6 carbon atoms. Typical aikenylene radicals include, but are not limited to, 1 ,2-ethylene (-CH=CH-).

"Alkynylene" refers to an unsaturated, branched or straight chain or cyclic hydrocarbon radical having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkyne. For example, an alkynylene group can have 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 8 carbon atoms. Typical alkynylene radicals include, but are not limited to, acetylene (~C=C-), propargyl {-Cr-kCnCR and 4-pentynyl (-CH2CH2CH2OC-).

When an alkyl, alkenyl or aikynyl group has the generalized prefix (C_n~ C_m), such as, for example, (CrC₃)alkyi, it is to be understood that the term provides for the number of carbons in the hydrocarbon chain. Thus, for example, (Ci-C₃)aiky! includes methyl, ethyl, n-propy! and sec-propyi. If the indicated group is optionally substituted, then, for example, the term (CrG₃)alky! would also provide for substituted hydrocarbons of the indicated number of the carbon "backbone," for illustration, and without limitation, a (Ci-C- aikyl

optionally substituted with halo would encompass methyl, monofluoromethyi, dif!uoromethyl, trifjyoromethy!, monofluoroethyf, chlorodifluoromethyl, iodoethyl, 2-bromopropyl, and the like. "Amino" refers to a primary, secondary or tertiary amine group of the generalized formula -NRR\ where when R and R' are both H, a primary amine is referenced, where either R or R^: is H and the other is not, a secondary amine is referenced, and where both R and R^! are other than H, a tertiary amine is referenced.

"Amido/'carboxamide" and "amide" refer to a group of general formula:

"Aryi" means a monovalent aromatic hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system. For example, an aryi group can have 8 to 20 carbon atoms, 8 to 14 carbon atoms, or 6 to 12 carbon atoms. Typical aryi groups include, hut are not limited to, radicals derived from benzene (e.g., phenyl), substituted benzene, naphthalene, anthracene, biphenyl, and the like.

"Aryiene" refers to an aryi as defined above having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent aryi. Typical aryiene radicals include, but are not limited to, phenylene.

The term "halo" means Fluorine, Chlorine, Bromine or Iodine.

When used in conjunction with another subsfitueni such as "haloalkyi"' one or more hydrogens in the moiety is replaced by a halogen selected Independently from Fluorine, Chlorine, Bromine and Iodine.

The term "Cycloalkyl" refers to a saturated or partially unsaturated ring having 3 to 7 carbon atoms as a monocycle, 7 to 12 carbon atoms as a bicycle, and up to about 20 carbon atoms as a polycycie. Monocyclic cycloalkyl groups have 3 to 6 ring atoms, still more typically 5 or 8 ring atoms. Bicyclic cycloalkyl groups have 7 to 12 ring atoms, e.g., arranged as a blcyclo (4,5), (5,5), (5,6) or (8,8) system, or 9 or 10 ring atoms arranged as a bicyclo (5,8) or (6,6) system. Cycloalkyl groups include hydrocarbon mono-, bk and poly-cyclic rings, whether fused, bridged, or spire. Non-limiting examples of monocyclic cycioalkyis include cyclopropyi, cyclobutyl, cyclopentyl, 1- cyclopant-1-enyl, 1 -cyclopent-2-enyi_s 1-cyclopent-3~enyl, cyciobexy!, 1- cyclohex-1 -enyl, 1 -cydohex^»2~enyi, 1 -cyciohex-3-enyl, and the like.

"Cycfoalkoxy" refers to a cycloa!ky! that is attached to the adjacent moiety through an oxygen atom.

"Cycioalkylene" refers to a cycloalky! as defined above having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent cydoaikyl. Typical

cycioa!kyiene radicals include, hut are not limited lo, cyclopropylene and eyciopentylene. The term "aryl," as used herein, means phenyl or naphthyl.

The term "heterocycie," as used herein, means a cyclic saturated or partially unsaturated (but not aromatic} group containing carbon and at least one heteroatom, such as Oxygen, Nitrogen, or Sulfur, in the ring structure,

"Heterocycie" or "heterocyciyf refers to a saturaied or partially saturated cyclic group having from 1 to 14 carbon atoms and from 1 to 6 heteroatorns selected from N, S, P, or O, and includes single ring and multiple ring systems including, fused, bridged, and spiro ring systems. When a "heterocycie" or "heteroaryr Is prefaced by the term ^:!/>membered," then the total number of atoms, both carbon atoms and heteroatorns, is indicated. Non-limitative examples of heterocycies include;

and the like, Heterocycfes of the present invention may be unsubstituted, or substituted with one or more ha!o, (Ci ~ C4) alkyl, hydroxy!, C_t - C4) haioalkyi The term "nitrogen containing heterocycle,⁹ as used herein, means a heterocy e with at ieas one nitrogen atom.

The term "heteroaryl," as used herein, "means a monovalent aromatic cyclic group having at least one heteroatom in the ring. Thus, "heteroaryl" refers to an aromatic group of from 1 to 14 carbon atoms and 1 to 6 heteroatoms selected from oxygen, nitrogen, sulfur, or phosphorous. For multiple ring systems, by way of example, the term "heteroaryl" includes fused, bridged, and spiro ring systems having aromatic and non-aromatic rings. In one embodiment, the carbon, nitrogen, or sulfur ring atom(s) of the heteroaryl group may be oxidized to provide for C(^~0), M oxide, sulfinyl, or sulfonyl moieties.

Non-limiting examples of heteroaryl rings include pyridiny!, pyrroiyl, oxazo!yl, indolyl, isoindoiyl, purinyl, furanyl, thienyl, benzofuranyi. benzothiopheny!, carbazolyl, imidazoiyl, thiazolyl, isoxazolyl, pyrazolyi, isothiazolyl, quinoiyl, isoquinolyl, pyridazyl, pyrimidy!, pyrazyi, and the like.

When there is a sulfur atom present, the sulfur atom can be at different oxidation levels, namely, S, SO, SO2, or SO3. ΑΠ such oxidation levels are within the scope of the present invention.

"Sulfonyl" refers to a moiety of general structure

"Aminosu!fonyf refers to a moiety of general structuf

"Alkyisulfonyl" refers to a moiety of general structure:

wherein R is an aikyi group as defined herein.

A wavy line ( *- } represents the point of attachment of a substiiuent.

The term "substituted" in reference to a particular moiety of the compound of the Formulae of the invention, for example, "substituted aryl", refers to a moiety in which one or more hydrogen atoms are each

independently replaced with a non-hydrogen substiiuent. Divalent groups may also be simiiariy substituted.

Those skilled in the art will recognize that when moieties such as "aikyi", "aryl", "heterocyclyP, etc. are substituted with one or more substituents, they could alternatively be referred to as "alkylene", "ary!ene", "heterocyc!yiene", etc. moieties (i.e., Indicating that at least one of the hydrogen atoms of the parent "aikyi", "aryl", "heterocyclyP moieties has been replaced with the indicated subsfituent(s)). When moieties such as "aikyi", "aryl", "heterocyclyP, etc. are referred to herein as "substituted" or are shown diagrammatlcally to be substituted (or optionally substituted, e.g., when the number of substituents ranges from zero to a positive integer), then the terms "alky!", "aryl",

"heierocyclyl", etc. are understood to be interchangeable with "aikylene", "ary!ene", "heterocyc!y!ene", and the like,

As will be appreciated by those skilled in the art, the compounds of the present invention may exist in soivated or hydrated form. The scope of the present invention includes such forms. Again, as will be appreciated by those skilled in the art, the compounds may be capable of esteriflcatiom The scope of the present invention includes esters and other physiologically functional derivatives. The scope of the present invention includes prodrug forms of the compound herein described.

"Ester" means any ester of a compound in which any of the -COOH functions of the molecule is replaced by a -C(0)O function, or in which any of the - OH functions of the molecule are replaced with a ~OC(0)R function, in which the R moiety of the ester is any carbon-containi g group which forms a stable ester moiety, including but not limited to alky!, alkenyl, aikynyl, cycloalkyl, cycloalkylalkyi, aryl, arylalky!, heterocyelyl, heterocyclyialkyl and substituted derivatives thereof.

Protecting Groups

In the context of the present invention, protecting groups include prodrug moieties and chemical protecting groups.

Protecting groups are available, commonly known and used, and are optionally used to prevent side reactions with the protected group during synthetic procedures, i.e. routes or methods to prepare the compounds of the invention. For the most part the decision as to which groups to protect, when to do so, and the nature of the chemical protecting group "PG" will be dependent upon the chemistry of the reaction to be protected against (e.g., acidic, basic, oxidative, reductive or other conditions) and the intended direction of the synthesis. The PG groups do not need to be, and generally are not, the same if the compound is substituted with multiple PG. In general, PG will be used to protect functional groups such as carboxyi, hydroxyl, thio, or amino groups and to thus prevent side reactions or to otherwise facilitate the synthetic efficiency. The order of deprotection to yield free, deprotected g grroouuppss iiss ddeeppeennddeenntt uuppoonn tthhee iinntteennddeedd ddiirreeccttiioonn ooff tthhee ssyynntthheessiiss a anndd tthhee¬rree--aaccttiioonn ccoonnddiittiioonnss ttoo bbee eennccoouunntteerreedd,, aanndd mmaayy o occccuurr iinn aannyy oorrddeerr aass ddeetteerrmmiinneedd bbyy tthhee aarrttiissaann..

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Suitable acid addition salts are formed from acids which form non-toxic salts. Examples include the acetate, aspartate, benzoate, besylafe, bicarbonate/carbonate, bisulphaie/suiphate, borate, camsy!ate, citrate, edisyfate, esyiaie, formate, fumarate, gfuceptate, gluconate, giucuronate, hexafiuorophosphate, hibenzate, hydrochloride/chloride, hydrobrornide/bromide, hydroiodide/iodide, isethionate, lactate, maiate, ma!eate, malonate, mesylate, methy!sulphate, naphthyiate, 2- napsylafe, nicotinate, nitrate, orotate, oxalate, pa imitate, pamoate, phosphate/hydrogen phosphate/dihydrogen phosphate, saccharate, stearate, succinate, tartrate, tosy!ate and irifiuoroacetate salts.

Suitable base salts are formed from bases which form non-toxic salts. Examples include the aluminium, arginine, benzathine, calcium, choline, diethylamine, diolarnlne, glycine, lysine, magnesium, meglumine, olamine, potassium, sodium, tromethamine and zinc salts.

Included within the scope of the invention, and the term "salts" and "pharmaceutically acceptable salts" are complexes such as ciafhrafes, drug-host inclusion complexes wherein, in contrast to the aforementioned solvates, the drug and host are present in stoichiometric or non-stoichiometric amounts, Also included are complexes of the drug containing two or more organic and/or inorganic components which may be in stoichiometric or non-stoichiometric amounts. The resulting complexes may be ionised, partially ionised, or non-ionised.

The compounds of the invention include compounds of formula (I) as hereinbefore defined, polymorphs, and isomers thereof (including optical, geometric and tautomeric isomers) as hereinafter defined and isotopicaily-!abe!ed compounds of formula (I).

Compounds of formula (I) containing one or more asymmetnc carbon atoms can exist as two or more stereoisomers. Where a compound of formula (1) contains an alkenyl or alkenyiene group, geometric cisltrans (or Z/E) Isomers are possible. Where the compound contains, for example, a keto or ox!me group or an aromatic moiety, tautomeric isomerism ('tautomerism') can occur. It follows that a single compound may exhibit more than one type of isomerism.

Included within the scope of the present invention are ail stereoisomers, geometric isomers and tautomeric forms of the compounds of formula (I), including compounds exhibiting more than one type of isomerism, and mixtures of one or more thereof. Also included are acid addition or base salts wherein the counterion is optically active, for example, D-lactate or L-lysine, or racemic, for example, DL- Cisltrans^' isomers may be separated by conventional techniques well known to those skilled in the art, for example, chromatography and fractional crystallisation.

Conventional techniques for the preparation/Isolation of individual enantiomers Include c tra! synthesis from a suitable optically pure precursor or resolution of the racemate (or the racemate of a salt or derivative) using, for example, chirai high pressure liquid chromatography (HPLC).

Alternatively, the racemate (or a raeemic precursor) may be reacted with a suitable opticaiiy active compound, for example, an alcohol, or, in the case where the compound of formula (I) contains an acidic or basic moiety, an acid or base such as tartaric acid or 1 ~pbeny1ethy!amsne. The resulting diastereomeric mixture may be separated by chromatography and/or fractional crystallization and one or both of the diasiereorsomers converted to the corresponding pure enantiomer(s) by means well known to a skilled person.

Chirai compounds of the invention (and chira! precursors thereof) may be obtained in enantiomerically-enriched form using chromatography, typically HPLC, on an asymmetric resin with a mobile phase consisting of a hydrocarbon, typically heptane or hexane, containing from 0 to 50% isopropanol, typically from 2 to 20%, and from 0 to 5% of an alkyiamlne, typically 0.1% diethylamine. Concentration of the eluate affords the enriched mixture,

Mixtures of stereoisomers may be separated by conventional techniques known to those skilled in the art. [~ see, for example, "Stereochemistry of Organic Compounds" by E L Eliel (Wiley, New York, 1994).]

The present invention includes all pharmaceutically acceptable isotopica!ly- labelled compounds of formula (I) wherein one or more atoms are replaced by atoms having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number usually found in nature.

Examples of isotopes suitable for inclusion in the compounds of the Invention include isotopes of hydrogen, such as ²H and ³H, carbon, such as ¹¹C, ¹³C and ¹ C, chlorine, such as ³⁶CI, fluorine, such as ¹⁸F, iodine, such as ¹²³l and ¹²⁵l, nitrogen, such as ¹³N and ¹⁵N, oxygen, such as ¹⁵0, ¹⁷0 and ¹⁸0, phosphorus, such as ³²P, and sulphur, such as ³⁵S.

Certain isotopicalSy-iabelled compounds of formula (I), for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. ³H, and carbon- 4, /,e, ¹⁴C, are particularly useful for this purpose in view of their ease of incorporation and ready means of defection.

Substitution with heavier isotopes such as deuterium, i.e. ²H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances.

Substitution with positron emitting isotopes, such as ¹¹C, ¹⁸F, ^δΟ and ¹³N, can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy.

Isotopieaiiy-iabeled compounds of formula (!) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopicaily-labeled reagent© In place of the non-labeled reagent previously employed,

Compounds of the invention intended for pharmaceutical use may be administered 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,

The compounds of the invention intended for pharmaceutical use may be administered alone or in combination with one or more other compounds of the invention or in combination with one or more other drugs (or as any combination thereof). Generally, they will be administered as a formulation In association with one or more pharmaceutically acceptable excipienfs. The term "exeipienf is used herein to describe any ingredient other than the compound(s) of the invention. The choice of excipienl will to a iarge 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.

Oral Administration

The compounds of the invention may be administered orally. 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.

Formulations suitable for oral administration include solid formulations, such as tablets, capsules containing particulates, liquids, or powders; lozenges (including liquid-filled}, chews; muiti- and nano-particuiates; gels, solid solution, liposome, Rims (including muco-adhesive), 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, metbylcelluiose, or a suitable oil, and one or more emulsifying agents and/or suspending agents. Liquid formulations may also be prepared by the reconstituiion of a solid, for example, from a sachet.

For tablet dosage forms, depending on dose, the drug may make up from 1 t% to 80 wt% of the dosage form, more typically from 5 wt% to 60 wt% of the dosage form. in addition to the drug, tablets generally contain a disintegrant. Examples of disintegrate include sodium starch glycolate, sodium carboxymetnyl cellulose, calcium carboxymetnyl cellulose, croscarmellose sodium, crospovidone, polyvinylpyrrolidone, methyl cellulose, macrocrystalline cellulose, lower aikyl- substituted hydroxypropyl cellulose, starch, pregelatinised starch and sodium alginate. Generally, the disintegrant will comprise from 1 wt% to 25 t%, preferably from 5 wt% to 20 wt% of the dosage form.

Binders are generally used to Impart cohesive qualities to a tablet formulation. Suitable binders include microcrystaliine cellulose, gelatin, sugars, polyethylene glycol, natural and synthetic gums, polyvinylpyrrolidone, pregelatinised starch, hydroxypropyl cellulose and hydroxypropyl methyicelluio.se. Tablets may also contain diluents, such as lactose (monohydrate, spray-dried monohydrate, anhydrous and the like), mannitoi, xylitoi, dextrose, sucrose, sorbitol, microcrystaliine 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 t% to 5 wt% of the tablet, and glidants may comprise from 0.2 t% to 1 wt% of the tablet.

Tablets also generally contain lubricants such as magnesium stearate, calcium stearate, zinc stearate, sodium stearyl fumarate, and mixtures of magnesium siearate with sodium !aury! sulphate. Lubricants -generally comprise from 0.25 wt% to 10 wt%, preferably from 0,5 wt% to 3 wt% of the tablet,

Other possible ingredients include anfi-oxidants, colourants, flavouring agents, preservatives and taste-masking agents,

Exemplary tablets contain up to about 80% drug, from about 10 wt% to about

90 wt% binder, from about 0 wt% to about 85 wt% diluent, from about 2 wt% to about 10 wt% disintegrant, and from about 0.25 wi% to about 10 wt% 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 congeaied, or extruded before tabietting. The final formulation may comprise one or more layers and may be coated or uncoated; it may even be encapsulated.

The foregoing formulations for the various types of administration discussed above may be formulated to be immediate and/or modified retease. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

Parenteral . Administration

The compounds of the invention may also be administered directly into the blood siream, into muscle, or Info an internal organ. Suitable means for parenteral administration Include Intravenous, intraarterial, Intraperitoneal, intrathecal, intraventricular, intraurethra!, intrastemai, intracranial, intramuscular and subcutaneous. Suitable devices for parenteral administration include needle (including microneedle) injectors, needle-free injectors and Infusion techniques.

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 of formula (!) 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 immedsa and/or modified 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.

The compounds of the invention may also be administered topically to the skin or mucosa, that is, derrnaiiy or transdermaiiy. Typical formulations for this purpose include gels, hydrogeis, lotions, solutions, creams, ointments, dusting powders, dressings, foams, films, skin patches, wafers, implants, sponges, fibres, bandages and microemulsions. Liposomes may also be used. Typical carriers include alcohol, water, mineral oil, liquid petrolatum, white petrolatum, glycerin, polyethylene glycol and propylene glycol. Penetration enhancers may be

incorporated.

I n h ai ed/ ntra nasa I Ad m i n I stra tio n

The compounds of the invention can also be administered intranasaliy or by inhalation, typically in the form of a dry powder (either alone, as a mixture, for example, in a dry blend with lactose, or as a mixed component particle, for example, mixed with phospholipids, such as phosphatidylcholine) from a dry powder inhaler or as an aerosol spray from a pressurised container, pump, spray, atomiser (preferably an atomiser using electrohydrodynamics to produce a fine mist), or nebuliser, with or without the use of a suitable propeliant, such as 1 ,1 ,1 ,2-tetraf luoroethane or 1 ,1 ,1 ,2,3,3,3-heptafiuoropropane. For intranasal use, the powder may comprise a bioadhesive agent, for example, chitosan or cyclodexlrin.

Prior to use in a dry powder or suspension formulation, the drug product is micronised to a size suitable for delivery by inhalation (typically less than 5 microns). This ma be achieved by any appropriate comminuting method, such as spiral jet milling, fluid bed jet milling, supercritical fluid processing to form nanoparticles, high pressure homogenisaticn, or spray drying.

Capsules (made, for example, from gelatin or HPMC), blisters and cartridges for use in an Inhaler or insufflator may be formulated to contain a powder mix of the compound of the invention, a suitable powder base such as lactose or starch and a performance modifier such as /-leucine, mannttol, or magnesium stearate. The lactose rnay be anhydrous or in the form of the monohydrate, preferably the latter. Other suitable excipients include dextran, glucose, maltose, sorbitol, xy!itol, fructose, sucrose and trehalose.

A suitable solution formulation for use in an atomiser using electrohydrodynarntcs to produce a fine mist may contain from 1 pg to :20mg of the compound of the invention per actuation and the actuation volume may vary from 1 pi to ΙΟΟμΙ. A typical formulation may comprise a compound of formula (I), propylene giycol, sterile water, eihanol and sodium chloride. Alternative solvents which may be used instead of propyiene giycol include glycerol and polyethylene glycol.

Suitable flavours, such as menthol and ievomenthoi, or sweeteners, such as saccharin or saccharin sodium, may be added to those formulations of the invention intended for inhaied/intranasai administration.

Formulations for inhaied/intranasai administration may be formulated to be immediate and/or modified release using, for example, poly{DL-iactic-cog!ycoitc acid (PGLA). Modified release formulations include delayed- , sustained-, pulsed-, controlled-, targeted and programmed release. in the case of dry powder inhalers and aerosols, the dosage unit is determined by means of a valve which delivers a metered amount. Units in accordance with the invention are typically arranged to administer a metered dose or "puff" containing from 0.3 to 1000 pg of the compound of formula (I). The overall dally dose will typically be In the range 1 \JQ to 5 mg which may be administered in a single dose or, more usually, as divided doses throughout the day.

Recta l/i ntrayag i na I Ad m i s stra tion

The compounds of the invention may be administered rectaily or vaginally, for example, in the form of a suppository, pessary, or enema. Cocoa butter is a traditional suppository base, but various alternatives may be used as appropriate.

Other Technologies

The compounds of the invention may be combined with soluble macromoiecular entities, such as cyc!odextrin and suitable derivatives thereof or polyethylene glycol-contatning 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-cyciodextrin 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 compiexation with the drug, the cyc!odextrin may be used as an auxiliary additive, i.e. as a carrier, diluent, or soiubiiiser. Most commonly used for these purposes are alpha-, beta- and gamma- cyc!odextrins. Dosage

The compositions are preferabiy formulated in a unit dosage form. The term "unit dosage forms¹' refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient (e.g., a tablet, capsule, ampoule), The compounds are generally administered in a pharmaceutically effective amount.

Preferably, for oral administration, each dosage unit contains from 1 mg to 2 g of a compound described herein, and for parenteral administration, preferabiy from 0,1 to 700 mg of a compound a compound described herein. It wiii be understood, however, that the amount of the compound actually administered usually will be determined b a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered and its relative activity, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like. The physician will readily be able to determine doses for subjects whose weight falls outside this range, such as infants and the elderly.

Dosage regimens may be adjusted to provide the optimum desired response. For example, a single bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form, as used herein, refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the chemotherapeutic agent and the particular therapeutic or prophylactic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals.

Thus, the skilled artisan would appreciate, based upon the disclosure provided herein, that the dose and dosing regimen is adjusted in accordance with methods well-known in the therapeutic arts. That Is, the maximum tolerable dose can be readily established, and the effective amount providing a detectable therapeutic benefit to a patient may also be determined, as can the temporal requirements for administering each agent to provide a detectable therapeutic benefit to the patient. Accordingly, while certain dose and administration regimens are exemplified herein, these examples in no way limit the dose and administration regimen that may be provided to a patient in practicing the present invention.

It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated, and may include single or multiple doses. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compositions, and that dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed composition. For example, doses may be adjusted based on pharmacokinetic or pharmacodynamic parameters, which may include clinical effects such as toxic effects and/or laboratory values. Thus, the present invention encompasses intra- patient dose-escalation as determined by the skilled artisan. Determining appropriate dosages and regiments for administration of the chemotherapeutic agent are well-known in the relevant art and would be understood to be encompassed by the skilled artisan once provided the teachings disclosed herein.

A pharmaceutical composition of the invention may be prepared, packaged, or sold In bulk, as a single unit dose, or as a plurality of single unit doses, As used herein, a "unit dose" is discrete amount of the pharmaceutical composition comprising a predetermined amount of the active ingredient. The amount of the active ingredient is generally equal to the dosage of the active ingredient which would be administered to a subject or a convenient fraction of such a dosage such as, for example, one-half or one-third of such a dosage.

The relative amounts of the active ingredient, the pharmaceutically acceptable carrier, and any additional ingredients in a pharmaceutical composition of the invention will vary, depending upon the identity, size, and condition of the subject treated and further depending upon the route by which the composition is to be administered. By way of example, the composition may comprise between 0.1% and 100% (w/w) active ingredient.

Combination Therapy, including HCV Combination Therapy

In another embodiment, the compounds of the present invention may be combined with one or more active agent. Non-limiting examples of suitable combinations include combinations of one or more compounds of the present invention with one or more interferons, ribavirin or its analogs, HCV NS3 protease inhibitors, aipba-glucosidase 1 inhibitors, hepatoprotectants, nucleoside or nucleotide inhibitors of HCV NS5B polymerase, non-nucleoside inhibitors of HCV NS5B polymerase, HCV NS5A inhibitors, TLR-7 agonists, cyclophi!iin inhibitors, HCV IRES inhibitors, pharmacokinetic enhancers, and other drugs for treating HCV.

More specifically, one or more compounds of the present invention may be combined with one or more compounds selected from the group consisting of

1 } interferons, e.g., pegyiate rlFN-a!pha 2b (PEG-lntron), pegylated rlFM-alpha 2a (Pegasys), rIFN-aipha 2b (!ntron A), r!FN-aipha 2a (Roferon-A), interferon alpha {iv1QR~22, OPC-18, Alfaferone, Alfanative, ultiferon,

suhalin), interferon aifacon-1 (infergen), interferon alpha~n1 ( Vellferon), interferon a!pha~n3 (Alferon), interferon-beta (Avonex, DL-8234), interferon- omega (omega DUROS, Biomed 510), albinterferon aipha-2b (Albuferon), I FN alpha XL, BLX-883 (locteron), DA-3021 , glycosylated interferon aip a-2b (AVI-005), PEG-lnfergen, PEGylated interferon lambda (PEGylated IL-29), and belerofon,

2) ribavirin and its analogs, e.g., ribavirin (Rebeto!, Copegus), and tahbavirln (Viramidine),

3) HCV NS3 protease inhibitors, e.g., boceprevir (5CH-503034 , SCH- 7), telaprevir (VX-950), VX-813, T C-435 (TMC435350), ABT-450, B\~ 201335, Bl-1230, MK-7009, SCH-900518, VBY-376, VX-5Q0, GS-9256, GS- 9451 , BMS-790052, BMS-605339, PHX-1766, AS-101 , YH-5258, YH5530, YH5531 , and ITMN-191 (R-7227),

4) alpha-glucosidase 1 inhibitors, e.g., ceigosivir (MX-3253), Migiitoi, and UT-2318, 5) hepaioprotectants, e.g. , emericasan (!DN-6556), E-3738, GS-9450 (LB-84451 ), silibilin, and itoQ,

6) nucleoside or nucleotide inhibitors of HCV NS5B polymerase, e.g. , R1626, R7128 (R4048), IDX184, !DX-102, PSI-7851 , 8CX-4678,

valopicitabine (N -283), and MK-0608,

7) non-nucieoside inhibitors of HCV NS5B polymerase, e.g., fiiibuvir (PF-S6S554), ABT-333, ABT-072, BI-207127, VCH-759, VCH-916, JTK-652, MK-3281 , VBY-708, VCH-222, A848837, ANA-598, GL60667, GL59728, A- 63890, A-48773, A-48547, BC -2329, VCH-796 (nesbuvir), GSK625433, BILN- 1941 . XTL-2125, and GS-9190,

8) HCV NS5A inhibitors, e.g., AZD-2836 (A-831 ), AZD-7295 (A-689), and B S-790052,

9) TLR-7 agonists, e.g., imiquimod, 852A, GS-9524, ANA-773, ANA- 975, AZD-8848 (DSP-3025). PF-04878691 , and SM-360320,

10) cyc phillin inhibitors, e.g. , DEBiO-025, SCY-635, and NIM81 1 ,

11 ) HCV IRES inhibitors, e.g., MCi-067,

12} pharmacokinetic enhancers, e.g. , BAS-100, SPI-452, PF-4194477, IMC- 41629. GS-9350, GS-9585, and roxythromycin,

13) other drugs for treating HCV, e.g., thymosin alpha 1 (Zadaxin), nitazoxanide (Alinea, NTZ), BfVN-401 (v!rostat), PY -1 (aftirex),

KPE02003002, actilon (CPG-10101 ), GS-9525, KRN-7000, civacir, Gf-5005, XTL-6865. ΒΓΓ225, PTX-111 , ITX2S85, TT-033I, ANA 971 , NOV-205, tarvacin, EHC-18, VGX-410C, E Z-702, AVI 4065, BMS-650032, BMS- 791325, Bavituximab, DX-1 106 (ONO-4538), Og!ufanide, FK-788, and VX- 497 (merimepodsb).

In yet another embodiment, the present application discloses

pharmaceutical compositions comprising a compound of the present invention, or a pharmaceutically acceptable salt thereof, in combination with at least one additional active agent, and a pharmaceutically acceptable carrier or excipienl In yet another embodiment, the present application provides a combination pharmaceutical agent with two or more therapeutic agents in a unitary dosage form. Thus, it is also possible to combine any compound of the invention with one or more other active agents in a unitary dosage form. The combination therapy may be administered as a simultaneous or sequential regimen.. When administered sequentially, the combination may be administered in two or more administrations.

Co-administration of a compound of the invention with one or more other active agents generally refers to simultaneous or sequential

administration of a compound of the invention and one or more other active agents, such that therapeutically effective amounts of the compound of the invention and one or more other active agents are both present in the body of the patient

Co-administration includes administration of unit dosages of the compounds of the invention before or after administration of unit dosages of one or more other active agents, for example, administration of the

compounds of the invention within seconds, minutes, or hours of the administration of one or more other active agents. For example, a unit dose of a compound of the invention can be administered first, followed within seconds or minutes by administration of a unit dose of one or more other active agents. Alternatively, a unit dose of one or more other active agents can be administered first, followed by administration of a unit dose of a compound of the invention within seconds or minutes, In some cases, it may be desirable to administer a unit dose of a compound of the invention first, followed, after a period of hours {e.g., 1 -12 hours), by administration of a unit dose of one or more other active agents. In other cases, it may be desirable to administer a unit dose of one or more other active agents first, followed, after a period of hours (e.g., 1 -12 hours), by administration of a unit dose of a compound of the invention.

The combination therapy may provide "synergy" and "synergistic effect", i.e, the effect achieved when the active ingredients used together is greater than the sum of the effects that results from using the compounds separately. A synergistic effect may be attained when the active ingredients are: (1 ) co-formulated and administered or delivered simultaneously in a combined formulation; (2) delivered by alternation or in parallel as separate formulations; or (3) by some other regimen. When delivered in alternation therapy, a synergistic effect may be attained when the compounds are administered or delivered sequentially, e.g., in separate tablets, pills or capsules, or by different injections in separate syringes, in general, during alternation therapy, an effective dosage of each active ingredient is

administered sequentially, i.e. serially, whereas in combination therapy, effective dosages of two or more active ingredients are administered together.

Another embodiment of the present invention includes a method for treating a viral infection comprising administering a compound of the present invention. In one embodiment, the treatment results in one or more of a reduction in viral load or clearance of RNA.

Another embodiment of the present invention includes a method for treating or preventing HCV comprising administering a compound of the present invention. Another embodiment includes the use of a compound of the present invention for the manufacture of a medicament for the treatment or prevention of HCV.

Another embodiment of the present invention includes a method for treating a viral infection comprising administering a compound of the present invention. The compound is administered to a human subject in need thereof, such as a human being who is infected with a virus of the Flaviviridae family, such as hepatitis C virus. In one embodiment, the viral infection is acute or chronic HCV infection. In one embodiment, the treatment results in one or more of a reduction in viral load or clearance of RNA.

The effective dose ca be expected to be from about 0.001 to about 100 mg/kg body weight per day, typically from about 0.1 to about 50 mg/kg body weight per day, more typically from about 1 .0 to about 10 mg/kg body weight per day. Examples

The following non-limiting Preparations and Examples illustrate the preparation of compounds of the present invention.

¹H Nuclear magnetic resonance ( MR) spectra were in all cases consistent with the proposed structures, Characteristic chemical shifts (δ) are given in parts-per- miliion downfieid from tetramethylsi!ane using conventional abbreviations for designation of major peaks: e.g. s, singlet; d, doublet; t, triplet; q, quartet; m, multiple!; br, broad. The mass spectra (m/z) were recorded using either e!ectrospray ionisation (ESI) or atmospheric pressure chemical ionisation (APC1). The following abbreviations have been used for common solvents: CDCI₃, deuterochloroform; D₆~ DMSO, deuterodimethyisulphoxide; CD₃OD, deuteromethanol; THF, tetrahydrofuran. 'Ammonia' refers to a concentrated solution of ammonia in water possessing a specific gravity of 0,88, Where thin layer chromatography (TLC) has been used It refers to silica gel TLC using silica gel 60 F₂₅₄ plates, R_f is the distance travelled by a compound divided by the distance travelled by the solvent front on a TLC plate.

Scheme A

A-4 A-5

A-6

Scheme B

3-5

8-6

Scheme C

HATU, DIPEA, DMF

A- 4 C-1

C-2

6 (Example 1 )

4 ert-Byty!-2₅6-dichioro-8-met ylpyrido 3,2-d]pyrimidine (1)

2_i4,6-inch!oro-8"methyfpyrido[3,2--d]pyrirnidine (A-1 , prepared according to procedures described in W)2008/30021 ; WO2008/77651 and WO2010/2998) (5g, 20.25mmol) and Cut (226mg) was dissolved in THF (110ml). 22m! of 1 N solution of i-Bu gCi in THF was added at ~10°C. After stirred for 30min., the reaction mixture was warmed to room temperature. Ethyl acetate was added and washed with brine. The extract was dried and the solvent was removed. The residue was purified by silica gel column to afford 3.83g of 4-.tert~butyi~ 2,6-dich!oro-8-methyipyrido[3,2~d]pyrimtdtne (1). ¹HN R (CDCI₃); δ 7.54 (s, 1 H), 2.7 (s, 3H), 1.64 (s, 9H).

4 ert-Buiyl-6-chloro~8-meih !- -(2,2_s2-trifiuoroethyl)pyr!do 3,2- d]pynmldin-2-arnine {2}

Into the solution of 4~tert'butyl-2,6-dic ioro-8-methylpyrido 3,2-d3pyrimidine (D^»2)(2.eig, 10.5mmol) in N P (30ml) was added OIPEA (2.67g, 20,6mmo!) and trifluoroethylamine (1.44g, 14.5mmol). The reaction mixture was sealed and heated to 80°C for 3h. After cooled to room temperature, the reaction mixture was poued into water and extracted with ethyl acetate. The extract was washed with brine and dried. After the solvent was removed, the residue was purified by silica gel column to afford 2.24g of 4-teft-butyl-6~chloro~8- meihyl-N~(2,2.2 rif!uoroethy})pyndo[3,2-d]pyrirr!idin-2-arnfne (2). MS [M*Hf ⁵⁵⁵ 333.15 Methyl 4 ert-butyl-8"rnethyl-2-(2.2_s2 rifluoroethy{am!no)pyrido[3_s2^« dJpyrimsdine^»8 arbox iate (3)

4-iert-butyi~6-ch!oro-8-methyl~N-{2,2_>2-trifluoroethyl}pyrido[3,2-d3pyrimidin-2^ amine (2 (2.37g, 7.15mmoi) was dissolved in MeOH (40ml). TEA (1.6g,

17.9mmol) and Pd(dppf}₂ DC complex (1 .48g, I .Smmol) was added. The reaction was heated io 50°C under carbon monoxide for 2h. After cooled to room temperature, the reaction mixture was poured into water and extracted with ethyl acetate. The extract was washed with brine and dried. After the solvent was removed, the residue was punfsed by silica gel column to afford 1 ,68g of methyl 4 eri^uty!-8~me hyh2-(2,2,2 rifluoroethylamino)pyrido[3,2~ djpyrimid ine-6-carboxylate (3). MS [M+HJ* = 357.14

4 ert~foytyi»8-meth l«2-{2_?2₅2 rsfl orosthylamfrio5pyr5do[3,2«

d]pyrims line-6-carboh dra ide (4)

2^4 ert~buiy^8^»riiei y^2-(2₎2₈2 rifluoroeihy!amino)pyrido|3_!2^»

d]pyrim!d ne-6»carborsy )-N~{3~(d fluoromethyi)»3»

hydroxycyclobutyl)hydra2lnecarboihioan l e {5}

3 (5^„{4^„tert-buiyl°8~methy -2-(2_s2,2~tr§flyoroethyiamma}pyrido[3,2»

dJpyri sdirt-e-ylM ,3,4-oxad?a∞l-2^»ylamino)-1 - {difluoromefhyijcyc!obutanol (8) Compound 8 was prepared as example compound 1 via the above intermediates according to standard procedures.

4-iert~butyi-8~methyi~2-{2,2,2~^

carbohydrazide (4). MS Hf ~ 357.07

2- {4 ert-buiyl-8-methy!-2-(2,2,2 rifiuoroeihy!amino)pyrido[3,2-d3pyrimidme-6" carbonyi)~N~{3 difiuoromethyl)~3-hydroxycyclobutyi)hydrazinecarboihioamide (5). MS [M+H]⁺ = 535.99

3- (5-(4 ert-buiyi-8-methy!-2-{2,2,2 nfiuoroethyiamino)pyrido[3,2-d]pyrimidi

6-y;)- ,3_!4-oxadiazol-2~y1amino)~1 -(difiuoromethyl)cyclobuianoi (6). MS

[M+H « 502.17.

Example 2

6 (example 2)

3H^~f @rt»buiyf»2»{eih !amm©}«8«^

1 ,3,4-oxadsazol-2-y!amino}»1 »(difluoromethyl)cyclobutanoi (1 } Compound 6 {example compound 2) was prepared in the manners similar to example 1. MS +Hf = 448.21.

Examples 3 and 4

3 (example 3)

5 (example 4)

djpynrY¾idin»6^«y!}»N-{{1R,33)"3»m

(3, example compound 3) §-(4 eit»butyl»8»methy!»2«(2,2_>2 r^

d3pyrimidfn-6-y "^'({1S,3 )-3-methylcyc!ohexyf)-1 _s3,4~oxadiazoi-2-ami.ie (5, example compound 4}

Both example compounds 3 and 4 were prepared in the manners similar to example 1 .

Example compound 3: MS [M+H]* * 480.18

Example compound 4:. MS [M+H]^4'™ 480, 17

Examples 5

HATU, DIPEA, DMF

3 (Example 5} -{(1 ,4-dsoxan-2-y methyl)-4-iert-buty <<8^»methyl^»2~{2_s2_J2^»

trifkiometh lamino}pyrido|3,2'd]pyrimsd!ne-6-carboxamlde (Examp! compound 5)

Example compound 5 was prepared from intermediate 3 of example 1 according to Scheme C using standard conditions. MS [M÷Hj*^™ 442.19

Scheme G

A-1 2

6 { Example 6)

2 -D!chloro- ,N₍8 rimethyl yndo[3,2-d]pyrimid§n-4-aiii!ne (1)

2^_i6 nchlorO"8-methyipyndo[3,2'-d]pynmidlne (A-1 , from example 1) (1 J24g, Srnrnol) was dissolved in DMF (10ml). Dimethyiamine hydrochloride (449mg, 5.5mmol) and TEA (1 ,01 g, Gmmol) was added at room tempweraiure. After the reaction mixture was stirred at room temperature for 24h, the reaction mixture was poured into water and extracted with ethyl acetate. The extract was washed with brine and dried. After the solvent was removed, the residue was purified by silica gel column to afford 1 ,7g of 2,6 lichioro-N,N,8- trimethylpyridoi3,2-d]pyrimidin-4-amine (1), MS *Hf - 257.19 1-{dif5uoromethyJ)-3-(5-{4-{dimethylamtno)-8^«rneihyi*'2-i2,2,2" trifluoroethySamin }pyrido[3_s2-d]pyrim5din-©-yl)-1₅3_s4-oxadia2ol-2- ytamino)cyctahutanoi (Exampf compound 6),

Ex m le compound 8 was prepared in the manners similar to example 1. MS IM+H3^* = 489.2

Examples 7

6 (Example 7)

3·(5-(4-(3,3-ιϋΑυοΓθ3Ζβϋ(ϋη-1-γ!)-8-ή 6ΐΗνΙ·- *(2,2,2··

trlfluoroethy3amino)pyrido[3,2'd3pynmidin>6>yi)^»1_s3,4*oxadiai o9''2-' y!amfno)»1«{d fk oromethy!)cyciobytanol (Example compound 7) Example compound 7 was prepared in the manners similar to example 1 . MS [M+HJ⁺ = 537.18

Bsojogjcaj Data

Bioiogicai properties of the exemplified compounds were determined using the assay presented below, and the results are found in Table I. HCV repiicon assay

Compounds are tested for antiviral activity in the HCV repiicon harboring a reporter (human Reni!fa luciferase) and HCV subgenomic RNA derived from H7? (GTla), Con1 (GT1 b)_s or JFH~1 (GT2a) strain, Repiicon ceils are maintained In Dulbecco's Modified Eagle Medium (D EM) supplemented with glutamine, 10% FBS, 0.5 mg/mi of G-418, Pen-Strep, and non-essential amino acids. Ceils are seeded in 384-well assay plates. Compounds are serially diluted in 100% DMSO and subsequently added into ceils in assay plates at 1 :225. Following three day incubation at 37°C, the activity of Renilla luciferase in repiicon cells Is quantified as a marker of HCV replication using the Dual-Glo luciferase assay system from

Promega, Luciferase levels were converted into percentages relative to the untreated controls (defined as 100%) and data were fit to the logistic dose response equation y = a/(1 +(x b)^c) using a dose response tool. EC₅₀ values were calculated as the compound concentration (x) at 50% inhibition (y) from the resulting equations in which a represents the curve's amplitude, b is the x value at its transition center, and c is a parameter which defines its transition width,

Claims

1. A compound of Formu a I:

or a pharrnaceuticaHy acceptable salt thereof, wherein:

R¹ is (Ci - C₆) alky!, 0 - (d - C₆) atkyi, NR⁹R¹⁰,

R² is C(0)NR^{1 l}R ² , C{0)R¹³, 5 membered heterocycle, or

5 membered heieroaryl,

where X is O or S,

R⁴ is (Ci - C₆) alkyl, either unsubstituted or substituted with halo,

R⁹ is H , (d - d) alkyl, said (d - d) alky! being unsusbsiituted or substituted with one

or more halo, or

R^!0 is H, (Ci™ d) alkyl, said (d - d) alkyl being unsusbsiituted or substituted with one

or more halo, or R⁹ and R'°, together with the nitrogen atom to which they are attached, form a 4 or 5 membered nitrogen containing heterocycle, said 4 or 5 membered nitrogen containing heterocycle being unsubstituted or substituted with one or more halo,

R¹ is H, (Ci - d) alkyl, (d ~ d) haioalkyl, 5-6 membered heterocycle or

5-6 membered heteroaryl;

R¹² is H , (Ci - d) a!kyi or (d - d) haioalkyl; or

R ¹ and R¹², together with the nitrogen atom to which they are attached, form a 5 or 6 membered nitrogen containing heterocycie, said 5 or 6 membered nitrogen containing heterocycie being unsubstitutedR¹³ is OH, 0-(Ci - C₄) aikyl,

R¹ is R^,5R^'!6

R ⁵ is H, (C , - C_fi) alkyi, (C, - C₆) haioaikyl, 4-7 membered heterocycie, 5-6 membered

heteroaryt, 3-7 membered cycloalkyi, and wherein each of said 4-7

membered heterocycie, 5-6 membered heteroary!, 3-7 membered cyc!oaikyi is unsubstituted or substituted at a substitutabie position Wit one or more ~0, OH, (d - C₆) aikyl, {d - C₆) haioaikyl, (d - C₆) aikoxy, amino, or , (d - C₆) aminoaikyl; and

R¹⁶ is H, ( ~ C₆) aikyl, or {d - C_s) haioaikyl;

provided thai when one of R¹⁵ or R¹⁶ is H, the other is not H.

2. The compound of claim 1 wherein R² is a 5 membered heteroary!.

3. The compound of claim 2 wherein R² is

, and X is O, NH, CH, or S. 4. The compound of claim 1 wherein R² is C(0)f

5. The compound of claim 1 wherein R⁴ is (d - C₆) aikyl, either unsubstituted or substituted with halo, (d - C₆) aikoxy, or (Ci - Ce) haloalkoxy. 6. The compound of claim 1 wherein R¹ is (d ~ C₈} aikyl, (d-C₈) haioaikyl, amino, or (d~€s) haloalkoxy.

7. A compound of Formula II:

or a pharmaceutically acceptable salt thereof, wherein:

R is {Ci - C₆) alkyl, O - (d - C₈) alkyl, O - (C, - C₆) haloaikyl, NR⁹R ^'°, Halo,

(Cz-Ca) a!kenyl, C₂-C₈) alkynyi, (C C₆) haioaiky!, O ·^■■· (d - C₆) haloaikyl, (C₂- C₆) haioalkenyi, (C₂-C₆) haloa!kynyi, (Ci-C₆}alkoxy, or (Ci-C₆) haloaikoxy,;

R³ is H, (Ci - C₆) alkyl, (C C₆)a kenyl, (Ca-CeJalkynyi, (C C₃)a!koxy, amino, or (CrC.- haioalkyi;

R³ is H, (C, - Ce) alkyl, (C₂-C₆)alkenyl, (Ca-Cejalkynyl, (C C₃)aikoxy, amino, or (C -C₃)haloalkyi;

R⁴ is H, (C₁ - C₆) alky!, either unsubstituted or substituted with halo, <Ci - C₆) alkoxy, S(O), S(0)₂, S(0)CH₃, S(0)₂CH₃, C(Q)R^S, C(0)OR⁷ or iC₃~Ce}cycloalkyl, said (C₃~C₆)cycfoalky! being unsusbstituted or substituted with one or more halo, amino, (d^■·^■■ C₆) alkyl, or {C_r-C₃) haloaikyl

R^s is (Ci ~ C₆) alkyf, either unsubstituted or substituted with halo, or NR² R² ; and R⁶ is H, (Ci - C₆) alkyl, either unsubstituted or substituted with halo, or NR²¹R²²; or

R" and R⁶, togethe with the nitrogen atom to which they are attached, form a

5 or 6 membered nitrogen containing heterocycle, said 5 or 6 membered nitrogen containing heterocycle being unsubstituted or substituted with OH, halo, =0, or (d - C₆) alkyl.

or a pharmaceutically acceptable salt thereof, wherein:

X is O or S;

R is (C, - C₆) aikyi, O - (d - C₆) aikyi, 0 - (C, - C₆) haloalkyl, NR^SR¹⁰, Halo, ((¼- a!keny!, C₂-C₈) alkynyi, (C_r-C₆) haloalkyl, O - (d - C₆) haloalkyl, (C₂-C₆) haioalkeny!, (C₂-C_e) haioa!kynyl, {d-C₆}aikoxy, or {d-G₆) ha!oalkoxy,;

R³ is H, (d ~ C_s) aikyi, {C₂-C₆)aikenyi, {C₂-C₆)alkynyi, (d-C₃)alkoxy, amino, or (d-C₃)ha!oalkyi;

R^& is H, ( ~ C-e) aikyi, either unsubsiituted or substituted with halo, (d ~ C₆) alkoxy, S(O), S(0)₂, S(0)CH₃, S(0)₂CH_3s C(0)R⁶, C(0)OR⁷ or (C₃-C₆)cycloalkyl, said (C₃-C₆)cycioaikyl being unsusbsiituted or substituted with one or more halo, amino, (d™ C₅) aSky!, or (d-C₆) haloalkyl;

R⁶ is H, (Ci - C_e) alkyl or (d - C₆) haioa!kyl;

R⁷ is H, (Ci ~ C₆) alkyl or (d ~ C₆) hafoalky!;

R⁹ is H, (Ci - C₄) alkyl, said (Ci - C₄) alkyl being unsubsiituted or substituted with one

or more halo; and

R¹⁰ is H, (d - CA) aikyi, said ( - C₄) aikyi being unsusbstituted or substituted with one

or more halo, or R^s and R ⁰, together with the nitrogen atom to which they are attached, form a 4 or 5 membered nitrogen containing heterocycle, said 4 or 5 membered nitrogen containing heterocycle being unsubsiituted or substituted with one or more haio.

9. A compound selected from the group consisting of:

10. A pharmaceutical composition comprising a compound of claim 1 , or a

pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

11. A method of treating HCV in a patient in need thereof, comprising

administering to the patient a compound of formula I, or a pharmaceutically acceptable sail thereof.

12. Use of a compound of any of claims 1 -14 for treating HCV,

13. Use of a compound of any of claims 1 -14 for the manufacture of a

medicament for treating HCV.