WO2006100106A1

WO2006100106A1 - 3-carboxy pyrroles as anti-viral agents

Info

Publication number: WO2006100106A1
Application number: PCT/EP2006/002833
Authority: WO
Inventors: Richard Martin Grimes; Pritom Shah
Original assignee: Smithkline Beecham Corporation
Priority date: 2005-03-21
Filing date: 2006-03-20
Publication date: 2006-09-28
Also published as: GB0505735D0

Abstract

Novel antiviral compounds of Formula (I) : wherein: A represents hydroxy; R4 represents hydrogen and the other substituents are as defined in the claims; and salts, solvates and esters thereof; processes for their preparation, pharmaceutical compositions comprising them, and their use in HCV treatment are provided. .

Description

3-CARBOXY PYRROLES AS ANTI-VIRAL AGENTS

FIELD OF THE INVENTION

The present invention relates to novel 3-carboxy pyrrole derivatives useful as anti-viral agents. Specifically, the present invention involves novel inhibitors of Hepatitis C Virus (HCV) replication.

BACKGROUND OF THE INVENTION

Infection with HCV is a major cause of human liver disease throughout the world. In the US, an estimated 4.5 million Americans are chronically infected with HCV. Although only 30% of acute infections are symptomatic, greater than 85% of infected individuals develop chronic, persistent infection. Treatment costs for HCV infection have been estimated at $5.46 billion for the US in 1997. Worldwide over 200 million people are estimated to be infected chronically. HCV infection is responsible for 40-60% of all chronic liver disease and 30% of all liver transplants. Chronic HCV infection accounts for 30% of all cirrhosis, end-stage liver disease, and liver cancer in the U.S. The CDC estimates that the number of deaths due to

HCV will minimally increase to 38,000/year by the year 2010.

Due to the high degree of variability in the viral surface antigens, existence of multiple viral genotypes, and demonstrated specificity of immunity, the development of a successful vaccine in the near future is unlikely. Alpha-interferon (alone or in combination with ribavirin) has been widely used since its approval for treatment of chronic HCV infection. However, adverse side effects are commonly associated with this treatment: flu-like symptoms, leukopenia, thrombocytopenia, depression from interferon, as well as anemia induced by ribavirin (Lindsay, K.L. (1997) Hepatology 26 (suppl 1): 71S-77S). This therapy remains less effective against infections caused by HCV genotype 1 (which constitutes -75% of all HCV infections in the developed markets) compared to infections caused by the other 5 major HCV genotypes. Unfortunately, only -50-80% of the patients respond to this treatment (measured by a reduction in serum HCV RNA levels and normalization of liver enzymes) and, of responders, 50-70% relapse within 6 months of cessation of treatment. Recently, with the introduction of pegylated interferon (Peg-IFN), both initial and sustained response rates have improved substantially, and combination treatment of Peg-IFN with ribavirin constitutes the gold standard for therapy. However, the side effects associated with combination therapy and the impaired response in patients with genotype 1 present opportunities for improvement in the management of this disease.

First identified by molecular cloning in 1989 (Choo, Q-L et al (1989) Science 244:359-362), HCV is now widely accepted as the most common causative agent of post-transfusion non A, non-B hepatitis (NANBH) (Kuo, G et al (1989) Science 244:362-364). Due to its genome structure and sequence homology, this virus was assigned as a new genus in the Flaviviridae family. Like the other members of the Flaviviridae, such as flaviviruses (e.g. yellow fever virus and Dengue virus types 1-4) and pestiviruses (e.g. bovine viral diarrhea virus, border disease virus, and classic swine fever virus) (Choo, Q-L et al (1989) Science 244:359-362; Miller, R.H. and R.H. Purcell (1990) Proc. Natl. Acad. Sci. USA 87:2057-2061), HCV is an enveloped virus containing a single strand RNA molecule of positive polarity. The HCV genome is approximately 9.6 kilobases (kb) with a long, highly conserved, noncapped 5¹ nontranslated region (NTR) of approximately 340 bases which functions as an internal ribosome entry site (IRES) (Wang CY et al 'An RNA pseudoknot is an essential structural element of the internal ribosome entry site located within the hepatitis C virus 5' noncoding region' RNA- A Publication of the RNA Society. 1 (5): 526-537, 1995 JuI.). This element is followed by a region which encodes a single long open reading frame (ORF) encoding a polypeptide of -3000 amino acids comprising both the structural and nonstructural viral proteins.

Upon entry into the cytoplasm of the cell, this RNA is directly translated into a polypeptide of ~3000 amino acids comprising both the structural and nonstructural viral proteins. This large polypeptide is subsequently processed into the individual structural and nonstructural proteins by a combination of host and virally-encoded proteinases (Rice, CM. (1996) in B.N. Fields, D.M.Knipe and P.M. Howley (eds) Virology 2^nd Edition, p931-960; Raven Press, N.Y.). Following the termination codon at the end of the long ORF, there is a 3' NTR which roughly consists of three regions: an ~ 40 base region which is poorly conserved among various genotypes, a variable length poly(U)/polypyrimidine tract, and a highly conserved 98 base element also called the "3¹ X-tail" (Kolykhalov, A. et al (1996) J. Virology 70:3363-3371; Tanaka, T. et al (1995) Biochem Biophys. Res. Commun. 215:744-749; Tanaka, T. et al (1996) J. Virology 70:3307-3312; Yamada, N. et al (1996) Virology 223:255-261). The 3' NTR is predicted to form a stable secondary structure which is essential for HCV growth in chimps and is believed to function in the initiation and regulation of viral RNA replication.

The NS5B protein (591 amino acids, 65 kDa) of HCV (Behrens, S.E. et al (1996) EMBO J. 15:12-22), encodes an RNA-dependent RNA polymerase (RdRp) activity and contains canonical motifs present in other RNA viral polymerases. The NS5B protein is fairly well conserved both intra-typically (-95-98% amino acid (aa) identity across 1b isolates) and inter-typically (-85% aa identity between genotype 1a and 1b isolates). The essentiality of the HCV NS5B RdRp activity for the generation of infectious progeny virions has been formally proven in chimpanzees (A. A. Kolykhalov et al.. (2000) Journal of Virology, 74(4): 2046-2051). Thus, inhibition of NS5B RdRp activity (inhibition of RNA replication) is predicted to be useful to treat HCV infection.

Based on the foregoing, there exists a significant need to identify synthetic or biological compounds for their ability to inhibit HCV. SUMMARY OF THE INVENTION

The present invention involves novel 3-carboxy pyrrole compounds represented hereinbelow, pharmaceutical compositions comprising such compounds and use of the compounds in treating viral infection, especially HCV infection.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides at least one chemical entity chosen from compounds of Formula (I) :

wherein:

A represents hydroxy;

R¹ represents aryl, heteroaryl bonded through a ring carbon atom, or heterocyclyl bonded through a ring carbon atom, each of which may be optionally substituted by one or more substituents selected from -C_halky!, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R^D, -NR^EC0₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, -CF₃, -OCF₃, NR^ESO₂R^D, phenyl and heterocydyl, wherein the -C_1-6alky( substituent itself may be optionally substituted by one or more substituents selected from -Cs-gcycloalkyl, halo, -NR^BR^C, -C(O)NR^BR^G, -NR^EC(0)R°, -SR^A, -SO₂R⁰, -0R^A, oxo, phenyl, heteroaryl or heterocyclyl; or R¹ represents -C_1-ealkyl or -C_5-9cycloalkyl;

R² represents phenyl substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR⁵R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(0)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R² represents -(CH₂)_nC_5-7cycloalkyl optionally substituted on the cycloalkyl by one or more substitutents selected from -C-,.₆alkyl, =CH(CH₂)_tH, -0R^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, - NR^BR° -NR^EC(0)R°, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, and heterocyclyl, or wherein two substituents may together form a C_1-2alkylene bridge substituent;

t represents O, 1 , 2, 3 or 4;

n represents O or 1 ;

R³ represents heterocyclyl or heteroaryl; or phenyl optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R^D, -NR^ECO₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R³ represents -Ci.₆alkyl optionally substituted by one or more substituents selected from -C_1-6alkyl, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^ECO₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, phenyl, heteroaryl and heterocyclyl;

R⁴ represents hydrogen;

R^A represents hydrogen, -Ci_-6alkyl, arylalkyl, heteroaryialkyl, aryl, heterocyclyl or heteroaryl;

R^B and R^c independently represent hydrogen, -C_1-6alkyl, aryl, heterocyclyl or heteroaryl; or R^B and R^c together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

R° is selected from the group consisting of -C_1-6alkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, and heteroaryialkyl;

R^E represents hydrogen or -C_1-6alkyl;

R^F and R^G are independently selected from the group consisting of hydrogen, -C_1-6alkyl, aryl, heteroaryl, arylalkyl, and heteroaryialkyl; or R^F and R^G together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

and salts, solvates and esters thereof.

There is provided as a further aspect of the present invention at least one chemical entity chosen from compounds of Formula (I) and physiologically acceptable salts, solvates and esters thereof for use in human or veterinary medical therapy, particularly in the treatment or prophylaxis of viral infection, particularly HCV infection.

It will be appreciated that reference herein to therapy and/or treatment includes, but is not limited to prevention, retardation, prophylaxis, therapy and cure of the disease. It will further be appreciated that references herein to treatment or prophylaxis of HCV infection includes treatment or prophylaxis of HCV-associated disease such as liver fibrosis, cirrhosis and hepatocellular carcinoma.

In a further or alternative aspect there is provided a method for the treatment of a human or animal subject with viral infection, particularly HCV infection, which method comprises administering to said human or animal subject an effective amount of at least one chemical entity chosen from compounds of Formula (I) and physiologically acceptable salts, solvates and esters thereof. According to another aspect of the invention, there is provided the use of at least one chemical entity chosen from compounds of Formula (I) and physiologically acceptable salts, solvates and esters thereof in the manufacture of a medicament for the treatment and/or prophylaxis of viral infection, particularly HCV infection.

It will be appreciated that the chemical entities of the present invention may contain one or more asymmetric carbon atoms and may exist in racemic, diastereoisomeric, and optically active forms. All of these racemic compounds, enantiomers and diastereoisomers are contemplated to be within the scope of the present invention.

In one aspect, R¹ represents phenyl, heteroaryl bonded through a ring carbon atom, or heterocyclyl bonded through a ring carbon atom, each of which may be optionally substituted by one or more substituents selected from -C_1-ealkyl, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -SO₂R⁰, cyano, -CF₃, -OCF₃, NR^ESO₂R°, phenyl and heterocyclyl, wherein the -C_1-6alkyl substituent itself may be optionally substituted by one or more substituents selected from -C_5-9cycloalkyl, halo, -NR^BR^C, -C(O)NR^BR^C, -NR^EC(O)R°, -SR^A, -SO₂R⁰, OR^A, phenyl, heteroaryl or heterocyclyl; or R¹ represents -C_1-6alkyl or -C_5- gcycloalkyl (in another aspect optionally substituted cyclohexenyή. In a further aspect, R¹ represents phenyl, 4-iodophenyl or 4-ethynylphenyl.

In one aspect, R² represents optionally substituted C_5-7cycloalkyl, especially C_5-7cycloalkyl substituted by C_1-4alkyl. In another aspect, R² represents optionally substituted -C_5- ₆cycloalkyl. In yet another aspect R² represents -C₆cycloalkyl substituted by -C_1-4alkyl, especially frans-4-methylcyclohexyl.

In one aspect, R³ represents optionally substituted heterocyclyl or C_1-4alkyl. In a further aspect, R³ represents 1-methylethyl, 2-methoxyethyl, 2-(methoxy)-1-[(methoxy)methyl]ethyl, tetrahydro-2H-pyran-4-yl, tetrahydro-2H-pyran-4-ylmethyl, tetrahydro-2H-furan-3-yl or [1- (methylsulfonyl)-4-piperidinyl]. In another aspect, R³ represents optionally substituted heterocyclyl or unsubstituted C_1-4alkyl. In a further aspect, R³ represents 1-methylethyl, tetrahydro-2H-pyran-4-yl, tetrahydro-2H-furan-3-yl or [1-(methylsulfonyl)-4-piperidinyl].

It is to be understood that the present invention covers all combinations of aspects, suitable, convenient and preferred groups described herein.

As used herein, "acetyl" refers to -C(O)CH₃.

As used herein, "acetylamino" refers to -N(H)C(O)CH₃.

As used herein unless otherwise specified, "alkyl" refers to an optionally substituted hydrocarbon group. The alkyl hydrocarbon group may be linear, branched or cyclic, saturated or unsaturated. Where the alkyl group is linear or branched, examples of such groups include methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl or hexyl and the like. Where the alkyl hydrocarbon group is unsaturated, it will be understood that there will be a minimum of 2 carbon atoms in the group, for example an alkenyl or alkynyl group. Where the alkyl hydrocarbon group is cyclic, it will be understood that there will be a minimum of 3 carbon atoms in the group. In one aspect, alkyl moieties are -C_1-4alkyl. Unless otherwise stated, optional substituents include -C_1-6alkyl (unsubstituted), =CH(CH₂)_tH, fluoro, -CF₃, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^EC0₂R^D, -NR^EC(0)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, oxo, aryl, heteroaryl and heterocyclyl.

As used herein, the term "alkenyl" refers to a linear or branched hydrocarbon group containing one or more carbon-carbon double bonds. In one aspect the alkenyl group has from 2 to 6 carbon atoms. Examples of such groups include ethenyl, propenyl, butenyl, pentenyl or hexenyl and the like.

As used herein, the term "alkynyl" refers to a linear or branched hydrocarbon group containing one or more carbon-carbon triple bonds. In one aspect the alkynyl group has from 2 to 6 carbon atoms. Examples of such groups include ethyny], propyny], butynyl, pentynyl or hexynyl and the like.

As used herein unless otherwise specified, "cycloalkyl" refers to an optionally substituted, cyclic hydrocarbon group. The hydrocarbon group may be saturated or unsaturated, monocyclic or bridged bicyclic. Where the cycloalkyl group is saturated, examples of such groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl and the like. Where the cyc\oa)ky\ group is unsaturated, examples of such groups include cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl or cyclooctenyl and the like. In one aspect, the cycloalkyl group has from 5 to 7 carbon atoms. In one aspect, cycloalkyl moieties are cyclohexenyl, cyclopentenyl and cyclohexyl. Unless otherwise stated, the cycloalkyl group may be substituted by one or more optional substituents including -C_halky! (unsubstituted), =CH(CH₂)_tH, fluoro, -CF₃, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, oxo, phenyl and heterocyclyl.

As used herein, the term " alkoxy" refers to an -O-alkyl group wherein alkyl is as defined herein. Examples of such groups include methoxy, ethoxy, propoxy, butoxy, pentoxy or hexoxy and the like.

As used herein, "aryl" refers to an optionally substituted aromatic group with at least one ring having a conjugated pi-electron system, containing up to two conjugated or fused ring systems. "Aryl" includes carbocyclic aryl and biaryl groups, all of which may be optionally substituted. In one aspect, "aryl" moieties contain 6-10 carbon atoms. In one aspect, "aryl" moieties are unsubstituted, monosubstituted, disubstituted or trisubstituted phenyl. In one aspect, unless otherwise stated, "aryl" substituents are selected from the group consisting of -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^G, -NR^EC(O)R°, -NR^ECO₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, heterocyclyl, -CF₃, -OCF₃ and phenyl.

As used herein, "arylalkyl" refers to an aryl group attched to the parent molecular moiety through an alkyl group.

As used herein, "carbonyl" refers to -C(O)-.

As used herein, "cyano" refers to -CN.

As used herein, "halogen" or "halo" refer to a fluorine, chlorine, bromine or iodine atom. References to "fluoro", "chloro", "bromo" or "iodo" should be construed accordingly.

As used herein, "heteroaryl" refers to an optionally substituted, 5, 6, 8, 9 or 10 membered, aromatic group comprising one to four heteroatoms selected from N, O and S, with at least one ring having a conjugated pi-electron system, containing up to two conjugated or fused ring systems. In one aspect, "heteroaryl" moieties are unsubstituted, monosubstituted, disubstituted or trisubstituted (where applicable) pyridyl, pyrazinyl, thiazolyl, thienyl, benzodioxolyl, benzofuranyl, benzodioxinyl and indolyl. In one aspect, unless otherwise stated, "heteroaryl" substituents are selected from the group consisting of -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^G, -NR^EC(O)R°, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, heterocyclyl, -CF₃ and phenyl.

As used herein, "heteroarylalkyl" refers to a heteroaryl group attched to the parent molecular moiety through an alkyl group.

As used herein, "heterocyclic" and "heterocyclyl" refer to an optionally substituted, 5 or 6 membered, saturated or partially saturated, cyclic group containing 1 or 2 heteroatoms selected from N, optionally substituted by hydrogen, -C_1-6alkyl, -C(O)R⁰, -C(O)NR^BR^C, -C(O)OR⁴, -SO₂R⁰, aryl or heteroaryl; O; and S, optionally substituted by one or two oxygen atoms. Ring carbon atoms may be optionally substituted by -Ci_-6alkyl, -C(O)R⁰, or -SO₂R⁰. In one aspect, unless otherwise stated, "heterocyclic" moieties are unsubstituted or monosubstituted tetrahydro-2H-pyran-4-yl, piperidinyl and 1 ,2,3,6- tetrahyd ro-4-pyrid i nyl .

As used herein, "nitro" refers to -NO₂.

As used herein, "oxo" refers to =0. As used herein, "Ac" refers to "acetyl", "Et" refers to "ethyl", "iPr" refers to "isopropyl", "Me" refers to "methyl", "OBn" refers to "benzyloxy", and "Ph" refers to "phenyl".

In one aspect, chemical entities useful in the present invention may be chosen from compounds of Formula (I) selected from the group consisting of:

4-{1 -methylethylt^rans^-methylcyclohexyOcarbonyllaminoJ-i -phenyl-1 H-pyrrole-3-carboxylic acid;

4-[[(trans-4-methylcyclohexyl)carbonyl](tetrahydro-3-furanyl)amino]-1-phenyl-1 H-pyrrole-3- carboxylic acid; 1-(4-iodophenyl)-4-[[(trans-4-methylcyclohexyl)carbonyl](1-methylethyl)amino]-1 H-pyrrole-3- carboxylic acid; and

1-(4-ethynylphenyl)-4-[[(trans-4-methylcyclohexyl)carbonyl](1-methylethyl)amino]-1 H-pyrrole- 3-carboxylic acid;

and salts, solvates and esters, and individual enantiomers thereof where appropriate.

Also included in the present invention are pharmaceutically acceptable salt complexes. The present invention also covers the physiologically acceptable salts of the compounds of Formula (I). Suitable physiologically acceptable salts of the compounds of Formula (I) include acid salts, for example sodium, potassium, calcium, magnesium and tetraalkylammonium and the like, or mono- or di- basic salts with the appropriate acid for example organic carboxylic acids such as acetic, lactic, tartaric, malic, isethionic, lactobionic and succinic acids; organic sulfonic acids such as methanesulfonic, ethanesulfonic, benzenesulfonic and p-toluenesulfonic acids and inorganic acids such as hydrochloric, sulfuric, phosphoric and sulfamic acids and the like.

The present invention also relates to solvates of the compounds of Formula (I), for example hydrates.

The present invention also relates to pharmaceutically acceptable esters of the compounds of Formula (I), for example carboxylic acid esters -COOR, in which R is selected from straight or branched chain alkyl, for example n-propyl, n-butyl, alkoxyalkyl (e.g. methoxymethyl), aralkyl (e.g. benzyl), aryloxyalkyl (e.g. phenoxymethyl), aryl (e.g. phenyl optionally substituted by halogen, -C_1-4alkyl or -C_1-4alkoxy or amino); or for example - CH₂OC(O)R' or -CH₂OCO₂R' in which R' is alkyl (e.g. R' is f-butyl). Unless otherwise specified, any alkyl moiety present in such esters preferably contains 1 to 18 carbon atoms, particularly 1 to 4 carbon atoms. Any aryl moiety present in such esters preferably comprises a phenyl group.

It will further be appreciated that certain compounds of the present invention may exist in different tautomeric forms. All tautomers are contemplated to be within the scope of the present invention. PROCESSES

Compounds of Formula (I) in which A is hydroxy may be prepared from a compound of Formula (II)

in which A is a protected hydroxy group, for example an alkoxy, benzyloxy or silyloxy group and R¹, R², R³ and R⁴ are as defined above for Formula (I). For example when A is methoxy or ethoxy, and R¹, R², R³ and R⁴ are as defined above for Formula (I), by treatment with an appropriate base, for example aqueous sodium hydroxide or lithium hydroxide, optionally in a solvent such as methanol, tetrahydrofuran or combinations thereof. Suitably, the temperature is in the range 25 to 100⁰C, more preferably 50 to 100⁰C. Alternatively, when A is methoxy or ethoxy and R¹, R², R³ and R⁴ are as defined above for Formula (I), by treatment with lithium iodide in a suitable solvent such as pyridine, lutidine or collidine, suitably in the temperature range 100-170⁰C. For example when A is terf-butoxy, and R¹, R², R³ and R⁴ are as defined above for Formula (I), by treatment with an appropriate acid, for example trifluoroacetic acid. Suitably, the reaction is carried out in a solvent, for example dichloromethane. Suitably, the temperature is in the range 0 to 50⁰C, more preferably 15 to 30⁰C. For example when A is silyloxy, and R¹, R², R³ and R⁴ are as defined above for Formula (I), by treatment with a suitable fluoride source for example tetrabutylammonium fluoride. The reaction is carried out in a suitable solvent, for example tetrahydrofuran. Suitably, the temperature is in the range 0 to 50⁰C, more preferably 15 to 30⁰C.

Compounds of Formula (W) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared by removal of the P¹ Formula (III)

in which R¹, R², R³, R⁴ and A are as defined above for Formula (II), and P¹ is an acid or ester thereof, for example -COW wherein W is alkoxy, silyloxy, aryloxy or arylalkyloxy but W and A are always different to each other. Where P¹ is an ester, the group may be converted to acid in a first step. Where W is an acid, the group may be decarboxylated to leave hydrogen. For example when W is silyloxy, the group may be converted to an acid by treatment with a suitable fluoride source for example tetrabutylammonium fluoride. The reaction is carried out in a suitable solvent, for example tetrahydrofuran. Suitably, the temperature is in the range 0 to 50⁰C, more preferably 15 to 3O⁰C. For example, when W is benzyloxy, the group may be converted to an acid by hydrogenolysis using hydrogen gas with a catalyst such as palladium on carbon in a suitable solvent such as ethanol, optionally in the presence of a suitable acid, for example hydrochloric acid, and optionally conducting the reaction under pressure. For example, when W is ferf-butyloxy, the group P¹ may be removed (in a single reaction) with a suitable acid, for example hydrochloric acid or trifluoroacetic acid. Suitably, the reaction is carried out in a solvent, for example dichloromethane. Suitably, the temperature is in the range 50 to 7O⁰C.

Decarboxylation where W is an acid may be carried out using a suitable acid, for example hydrochloric acid or trifluoroacetic acid. Suitably, the reaction is carried out in a solvent, for example dichloromethane. Suitably, the temperature is in the range 50 to 70⁰C.

Compounds of Formula (II) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared by reaction of a salt of )

in which R¹, R³ and R⁴ are as defined above for Formula (I), and A is an alkoxy, benzyloxy or silyloxy group, with a suitable acylating agent, for example R²-C(O)-Y, wherein Y is a halo atom, for example chloro or bromo, and R² is as defined above for Formula (I). The reaction may be carried out in a suitable solvent, for example dichloromethane, in the presence of a suitable base, for example pyridine or triethylamine and thereafter removing any protecting group if desired. Alternatively, a phosphine such as triphenylphosphine may be used. Suitable protecting groups can be found, but are not restricted to, those found in T W Greene and P G M Wuts 'Protective Groups in Organic Synthesis', 3^rd Ed (1999), J Wiley and Sons.

Compounds of Formula (III) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared by reaction of a compo

in which R¹, R³ and R⁴ are as defined above for Formula (I), and A is an alkoxy, benzyloxy or silyloxy group, and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, with a suitable acylating agent, for example R²-C(0)-Y, wherein Y is a halo atom, for example chloro or bromo, and R² is as defined above for Formula (I). The reaction may be carried out in a suitable solvent, for example dichloromethane, in the presence of a suitable base, for example pyridine or triethylamine and thereafter removing any protecting group if desired. Alternatively, a phosphine such as triphenylphosphine may be used. Suitable protecting groups can be found, but are not restricted to, those found in T W Greene and P G M Wuts 'Protective Groups in Organic Synthesis', 3^rd Ed (1999), J Wiley and Sons.

Compounds of Formula (IVa) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared by reaction of a compound of Formula (IV) in which R¹, R³ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy group, and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other. The COW group may be converted to acid in a first step. Where W is an acid, the group may be decarboxylated to leave hydrogen. For example when W is silyloxy, the group may be converted to an acid by treatment with a suitable fluoride source for example tetrabutylammonium fluoride. The reaction is carried out in a suitable solvent, for example tetrahydrofuran. Suitably, the temperature is in the range 0 to 5O⁰C, more preferably 15 to 30⁰C.

For example, when W is benzyloxy, the group may be converted to an acid by hydrogenolysis using hydrogen gas with a catalyst such as palladium on carbon in a suitable solvent such as ethanol, optionally in the presence of a suitable acid, for example hydrochloric acid, and optionally conducting the reaction under pressure.

For example, when W is tβrt-butyloxy, the group P¹ may be removed (in a single reaction) with a suitable acid, for example hydrochloric acid or trifluoroacetic acid. Suitably, the reaction is carried out in a solvent, for example dichloromethane. Suitably, the temperature is in the range 50 to 70⁰C. Decarboxylation where W is an acid may be carried out using a suitable acid, for example hydrochloric acid or trifluoroacetic acid. Suitably, the reaction is carried out in a solvent, for example dichloromethane. Suitably, the temperature is in the range 50 to 70°C. This yields a compound of Formula (IVa) in the form of the relevant acid addition salt. It is this salt which is used in the preparation of a compound of Formula (II) as described above.

Compounds of Formula (IV) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared from compounds of For

in which R¹ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, by treatment with a suitable vinyl ether, or a suitable aldehyde or a suitable ketone in the presence of a suitable acid, such as acetic acid, and a suitable reducing agent such as sodium triacetoxyborohydride, in a suitable solvent such as dichloromethane. Alternatively, compounds of Formula (IV) in which A is an alkoxy, benzyloxy or silyloxy group may be prepared from compounds of Formula (V) by treatment with a suitable alkylating agent R³-X where X is a halo group such as chloride, bromide or iodide, or X is a sulphonate ester such as methanesulfonate, in suitable solvent such as dimethylformamide in the presence of a suitable base such as triethylamine.

Compounds of Formula (V) may be prepared by reaction of compounds of Formula (Vl)

in which R¹ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy, and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, with a cyclisation agent, for example 1 ,8-diazobicyclo[5.4.0]undec-7-ene, in the presence of a suitable solvent, for example tetrahydrofuran. In one aspect, the reaction is carried out at a temperature in the range 50 to 100⁰C, suitably at 60⁰C.

Compounds of Formula (Vl) may be prepared by reaction of compounds of Formula

in which R¹ is as defined above for Formula (I) and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, with compounds of Formula (VIII) in which R⁴ and A are as defined above for Formula (II) and R' is -C_1-4alkyl (such as ethyl), under reflux in a suitable solvent such as toluene, in the presence of a suitable base, for example triethylamine.

Compounds of Formula (VIl) and (VlII) are commercially available or well known in the art.

Compounds of Formula (III) may also be prepared by reaction of a compound of Formula (IX)

in which R¹, R² and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy group, and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, with a suitable alkylating agent R³-X in which X is a halo atom such as chloro, bromo or iodo, or X is a sulphonate ester such as methanesulfonate, in a suitable solvent such as dimethylformamide, in the presence of a suitable base such as triethylamine and sodium hydride.

Compounds of Formula (IX) may be prepared from compounds of Formula (V) by reaction with a suitable acylating agent, for example R²-C(O)-Y, in which Y is a halo atom, preferably chloro or bromo, and R² is as defined above for Formula (I). Suitably, the reaction is carried out in a suitable solvent, for example dichloromethane, in the presence of a suitable base, for example pyridine or triethylamine. For example, where R² represents an aliphatic group, a phosphine such as triphenylphosphine may optionally be used in place of an amine base.

Compounds of Formula (IU) may also be prepared by reaction of a compound of Formula (X)

in which R², R³ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy group, and P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, by treatment with an aryl, heteroaryl, cycloalkenyl or alkenyl boronic acid in the presence of a copper catalyst such as copper (II) acetate. Suitably, the reaction is carried out in the presence of a base, such as pyridine, in air, and in a suitable solvent such as dichloromethane or THF. Alternatively, compounds of Formula (III) in which R¹ represents aryl or heteroaryl may be prepared by reaction of compounds of Formula (X) with an aryl or heteroaryl halide or triflate in the presence of a copper catalyst such as copper (I) iodide. Suitably, the reaction is carried out in the presence of a base such as potassium carbonate or /rans-1 ,2- diaminocyclohexane or a combination thereof in a suitable solvent such as dioxan or pyridine or a combination thereof. Compounds of Formula (X) may be prepared by deprotection of the ring nitrogen (P) of a compound of Formula (Xl)

in which R², R³ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy group, P¹ is an acid or ester thereof, for example -COW wherein W is alkyloxy, aryloxy or arylalkyloxy but W and A are always different to each other, and P is a suitable protecting group. Suitable protecting groups include, but are not restricted to, benzyl.

Benzyl groups can be removed by hydrogenation using hydrogen gas with a catalyst such as palladium on carbon in a suitable solvent such as ethanol, optionally in the presence of a suitable acid, for example hydrochloric acid or acetic acid, and optionally conducting the reaction under pressure.

It will be understood by those skilled in the art that compounds of Formula (Xl) may be prepared from compounds of Formulae (IV) or (V) in which the group R¹ is a protecting group (P) instead of a group as defined for Formula (I), by application of the synthetic routes described above in relation to the synthesis of compounds of Formula (III).

In a further aspect, compounds of Formula (II) may be prepared from compounds of Formula

in which R¹, R² and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy group, and P¹ is hydrogen, with a suitable alkylating agent R³-X in which X is a halo atom such as chloro, bromo or iodo, or X is a sulphonate ester such as methanesulfonate, in a suitable solvent such as dimethylformamide, in the presence of a suitable base such as triethylamine and sodium hydride.

Compounds of Formula (IXa) may be prepared from compounds of Formula (Va) R¹ ^PV"V^R4

) (Va)

H₂N COA in which R¹ and R⁴ are as defined above for Formula (I), A is an alkoxy, benzyloxy or silyloxy and P¹ is hydrogen, by reaction with a suitable acylating agent, for example R²-C(0)-Y, in which Y is a halo atom, preferably chloro or bromo, and R² is as defined above for Formula (I). Suitably, the reaction is carried out in a suitable solvent, for example dichloromethane, in the presence of a suitable base, for example pyridine or triethylamine. For example, where R² represents an aliphatic group, a phosphine such as triphenylphosphine may optionally be used in place of an amine base.

Compounds of Formula (Va) may be prepared from compounds of Formula (V) by application of the synthetic routes described above in relation to the synthesis of compounds of Formula (IVa) from compounds of Formula (IV).

In a further aspect, a compound of Formula (II) may be prepared by appropriate manipulation of another compound of Formula (II). For example, a compound of Formula (II) in which any substituent comprises -C_2-4alkenyl may be prepared from a suitable aldehyde or ketone substituent and a phosphorous ylid generated from a phosphonium salt in the presence of a suitable base, such as potassium te/t-butoxide, in a suitable solvent such as THF. Optionally, the trans and cis isomers may be separated by standard techniques known in the art

For example, a compound of Formula (II) in which any substituent comprises -C_2-4alkyl may be prepared by reduction of an alkenyl substituent, for example using hydrogen, optionally under pressure, in the presence of a suitable catalyst such as palladium on carbon, in a suitable solvent such as ethanol. For example, a compound of Formula (II) in which any substituent comprises -C(O)NR^AR^B may be prepared by reacting a suitable acid substituent with an amine (HNR^AR^B) in the presence of a coupling agent such as HATU, in the presence of a suitable base such as triethylamine, in a suitable solvent such as DMF. Alternatively, a compound of Formula (II) in which any substituent comprises -C(O)NR^AR^B may be prepared by reacting a suitable acid chloride substituent with an amine (HNR^AR^B) in the presence of a suitable base such as triethylamine, in a suitable solvent such as dichloromethane.

For example, a compound of Formula (II) in which any substituent comprises -NR^EC(O)R^D may be prepared by reacting a suitable amine substituent with a carboxylic acid (R⁰CO₂H) in the presence of a coupling agent such as HATU, in the presence of a suitable base such as triethylamine, in a suitable solvent such as DMF. Alternatively, a compound of Formula (II) in which any substituent comprises -NR^EC(O)R^D may be prepared by reacting a suitable amine substituent with an acid chloride in the presence of a suitable base such as triethylamine in a suitable solvent such as dichloromethane. For example, a compound of Formula (II) in which any substituent comprises -NR^ESO₂R^D may be prepared by reacting an amine substituent with a suitable sulfonyl chloride in the presence of a suitable base such as trietnylamine, in a suitable solvent such as dichloromethane. For example, a compound of Formula (II) in which any substituent comprises -SO₂NR^FR^G may be prepared by reacting a sulfonyl chloride substituent with a suitable amine (HNR^FR^G) in the presence of a suitable base such as triethylamine, in a suitable solvent such as dichloromethane. For example, a compound of Formula (II) in which any substituent comprises -(CH₂)_nSR^A, wherein n=0, 1 , 2, 3 or 4 may be prepared by reacting a thiol -(CH₂)_nSH substituent or a thiolate salt (for example sodium thiomethoxide) substituent with an alkyl halide R^AX wherein X is a halo atom such as bromo, in a suitable solvent such as DMF, in the presence of a suitable base such as triethylamine. For example, a compound of Formula (II) in which any substituent comprises -SO₂R^A may be prepared by oxidation of a compound in which a substituent represents -SR^A, using for example oxone, sodium periodate, 3-chloro perbenzoic acid, or hydrogen peroxide. For example, a compound of Formula (II) in which any substituent comprises -(CH₂)_nOR^A may be prepared by reacting an alcohol -(CH₂)_nOH substituent, wherein n=0, 1 , 2, 3, or 4, with an alkyl halide R^AX wherein X is a halo atom such as bromo in the presence of a suitable base such as triethylamine or sodium hydride, or a compound of Formula (II) in which any substituent comprises -(CH₂)_POR^A may prepared by reacting an alkyl halide -(CH₂)pX substituent, where p=1 , 2 or 3 and X is a halo atom such as bromo, with an alcohol R^AOH, optionally in the presence of a base such as triethylamine or sodium hydride, or with an alkoxide (for example sodium methoxide) in a suitable solvent such as DMF. For example, a compound of Formula (II) in which any substituent comprises -(CH₂)_nNR^AR^B, where n=0, 1, 2, 3, or 4, may be prepared by reacting an amine -(CH₂)_nNHR^B substituent with an alkyl halide R^AX wherein X is a halo atom such as bromo, in the presence of a suitable base such as triethylamine or sodium hydride, or a compound of Formula (II) in which any substituent comprises -(CH₂)_nNR^AR^B wherein n=0,1 , 2, 3, or 4, may be prepared by reacting an aldehyde substituent with an amine, in the presence of a reducing agent such as sodium triacetoxyborohydride, in a suitable solvent such as dichloromethane.

Esters of compounds of Formula (I), in which A is -OR where R is selected from straight or branched chain alkyl, arylalkyl, aryloxyalkyl, or aryl, may also be prepared by esterification of a compound of Formula (I) in which A is hydroxy by standard literature procedures for esterification.

It will be appreciated that compounds of Formula (I), (II), (III), (IV)₁ (IVa), (V), (IX), (X) and

(XI) which exist as diastereoisomers may optionally be separated by techniques well known in the art, for example by column chromatography or recrystallisation. For example, the formation of an ester using a chiral alcohol, separation of the resulting diastereoisomers, and subsequent hydrolysis of the ester to yield the individual enantiomeric acid of Formula (1), (II), (III), (IV), (IVa), (V), (IX), (X) and (Xl).

It will be appreciated that racemic compounds of Formula (I), (II), (III), (IV), (IVa), (V), (IX), (X) and (Xl) may be optionally resolved into their individual enantiomers. Such resolutions may conveniently be accomplished by standard methods known in the art. For example, a racemic compound of Formula (I), (II), (III), (IV), (IVa), (V), (IX), (X) and (Xl) may be resolved by chiral preparative HPLC. Alternatively, racemic compounds of Formula (I), (II), (III), (IV), (IVa), (V), (IX), (X) and (Xl) which contain an appropriate acidic or basic group, such as a carboxylic acid group or amine group may be resolved by standard diastereoisomeric salt formation with a chiral base or acid reagent respectively as appropriate. Such techniques are well established in the art. For example, a racemic compound may be resolved by treatment with a chiral acid such as (R)-(-)-1 ,1'-binaphthyl-2,2'-diyl-hydrogen phosphate or (- )-di-O,O'-p-tolyl-L-tartaric acid, in a suitable solvent, for example isopropanol. Alternatively, racemic acid compounds may be resolved using a chiral base, for example (S)-alpha methylbenzylamine, (S)-alpha phenylethylamine, (1 S, 2S)-(+)-2-amino-1-phenyl-1 ,3- propane-diol, (-) ephidrine, quinine, brucine. Individual enantiomers of Formula (II), (III), (IV), (IVa), (V), (IX), (X) and (Xl) may then be progressed to an enantiomeric compound of Formula (I) by the chemistry described above in respect of racemic compounds.

With appropriate manipulation and protection of any chemical functionality, synthesis of compounds of Formula (I) is accomplished by methods analogous to those above and to those described in the Experimental section. Suitable protecting groups can be found, but are not restricted to, those found in T W Greene and P G M Wuts 'Protective Groups in Organic Synthesis', 3^rd Ed (1999), J Wiley and Sons.

EXAMPLES

ABBREVIATIONS

STRATA cartridge Dual action SPE cartridge available from Phenomenex

SPE solid phase extraction column

HPLC high pressure liquid chromatography

DCM dichloromethane

DIPEA diisopropylethylamine

DMF dimethylformamide

THF tetrahydrofuran

EtOAc ethyl acetate

AcOH acetic acid

DME dimethoxyethane

DBU 1,8-Diazobicyclo[5.4.0]undec-7-ene

OASIS HLB cartridge Sample extraction cartridge available from Waters hrs hour HCI hydrochloric acid

MDAP HPLC reverse phase HPLC on a C₁₈ column using a two-solvent gradient elution with (A) water containing formic acid (0.1 %) and (B) acetonitrile-water (95:5 v/v) containing formic acid (0.05%) as the eluents, and analysis of the fractions by electrospray mass spectroscopy. ISCO Companion Automated flash chromatography equipment with fraction analysis by UV absorption available from Presearch.

All mass spectroscopy was performed using electrospray as the method of ionisation.

Intermediate 1

1 ,1 -Dimethylethyl Λ/-phenylglycinate

To a solution of triethylamine (5.97 g, 59 mmol) in dry acetonitrile (50 mL) was added aniline (5 g, 53 mmol) and t-butylbromoacetate (11.5 g, 59 mmol). The reaction was stirred at room temperature, under a nitrogen atmosphere, for 16 hours. Further t-butylbromoacetate (5.17 g, 27 mmol) was added and the reaction was stirred for a further 2 hours. The reaction was partitioned between DCM and water then passed through a hydrophobic frit. The organic phase was concentrated and purified using a 90 g silica Biotage flash column eluting with 2.5% EtOAc in cyclohexane to furnish the title compound. MS calcd for (C₁₂H₁₇NO₂ + H)⁺: 208 MS found (electrospray): (M+H)⁺ = 208

Intermediate 2

Ethyl (Z)-4-[(2-ferf-butoxy-2-oxoethyl)(phenyl)amino]-2-cyanobut-2-enoate

To a solution of tert-butyl Λ/-phenylglycinate (Intermediate 1, 8.Og, 38.5 mmol) in dry toluene

(80 mL) was added triethylamine (4.3 g, 42 mmol) and ethyl (ethoxymethylene)cyanoacetate (7.2g, 42 mmol). The reaction was stirred at 12O⁰C, under nitrogen atmosphere, for 24 hours. The reaction was cooled and partitioned between EtOAc and water. The organic layer was washed with brine, dried over Na₂SO₄ and concentrated. The crude material was purified using a 330 g silica ISCO Companion Flash column, eluting with a gradient of 5-50% EtOAc in cyclohexane to furnish the title compound. MS calcd for (C₁₈H₂₂N₂O₄ + H)⁺: 331 MS found (electrospray): (M+H)⁺ = 331

Intermediate 3

2-ferf-Butyl 4-ethyl 3-amino-1 -ph icarboxylate

To a solution of Intermediate 2 (5.9 g, 17.8 mmol) in dry THF (59 mL) was added DBU (2.72 g, 17.8 mmol). The reaction was stirred at reflux, under a nitrogen atmosphere, for 16 hours. The reaction was cooled, concentrated and purified using a 120 g silica ISCO Companion Flash column eluting with a gradient of 0-30% EtOAc in cyclohexane to furnish the title compound.

MS calcd for (C₁₈H₂₂N₂O₄ + H)⁺: 331 MS found (electrospray): (M+H)⁺ = 331

Intermediate 4 2-fe/t-Butyl 4-ethyl 3-(1 -methylet H-pyrrole-2,4-dicarboxylate

To a solution of Intermediate 3 (0.5 g, 1.51 mmol) in dry DCM (1OmL) was added 2- methoxypropene (0.43 g, 6.1 mmol), AcOH (0.36 g, 6.1 mmol) and sodium triacetoxyborohydride (0.64 g, 3.0 mmol). The reaction was stirred at room temperature, under a nitrogen atmosphere, for 16 hours. The reaction was quenched with saturated sodium bicarbonate and partitioned with DCM. This was passed through a hydrophobic frit and the organics concentrated. The crude material was purified using a 4 g silica ISCO Companion Flash column eluting with a gradient of 0-30% EtOAc in cyclohexane to furnish the crude title compound which was used without further purification. MS calcd for (C₂₁H₂₈N₂O₄ + H)⁺: 373 MS found (electrospray): (M+H)⁺ = 373 Intermediate 5

2-te/t-Butyl 4-ethyl 3-{1 -methylethyl[(frans-4-methylcyclohexyl)carbonyl]amino}-1 - phenyl-1H-pyrrole-2,4-dicarboxylate

To a solution of Intermediate 4 (0.47 g, 1.26 mmol) in dry DCM (7.5 mL) was added triethylamine (0.19 g, 1.89 mmol) and frans-4-methylcyclohexanecarbonyl chloride¹ (0.30 g,

1.89 mmol). The reaction was stirred at 45⁰C, under a nitrogen atmosphere, for 16 hours.

The reaction was cooled, diluted with DCM and washed with 1 N HCI and saturated sodium bicarbonate, passed through a hydrophobic and the organics concentrated. The crude material was purified using a 80 g silica ISCO Companion Flash column eluting with a gradient of 5-30% EtOAc in cyclohexane to furnish the title compound.

MS calcd for (C₂₉H₄₀N₂O₅ + H)⁺: 497

MS found (electrospray): (M+H)⁺ = 497

1. WO 2004/052885

Intermediate 6

Ethyl 4-{1-methylethyl[(frans-4-methylcyclohexyl)carbonyl]amino}-1-phenyl-1 H- pyrrole-3-carboxylate

To Intermediate 5 (100 mg, 0.2 mmol) was added trifluoroacetic acid (1 mL) and the readtion was stirred under reflux for 16 hours. The reaction was cooled, concentrated and purified using a 12 g silica ISCO Companion Flash column eluting with a gradient of 0-80% EtOAc in cyclohexane to furnish the title compound. MS calcd for (C₂₄H₃₂N₂O₃ + H)⁺: 397 MS found (electrospray): (M+H)⁺ = 397

Intermediate 7

Ethyl 4-amino-1-phenyl-1H-pyrrole-3-carbόxylate hydrochloride

To Intermediate 3 (0.5 g, 1.51 mmol) was added 4M hydrogen chloride in 1 ,4-dioxane (10 mL). The reaction was stirred at room temperature overnight and then solvent removed to furnish the title compound. MS calcd for (C₁₃H₁₄N₂O₂ + H)⁺: 231 MS found (electrospray): (M+H)⁺= 231

Intermediate 8 ethyl 4-{[(trans-4-methylcyclohexyl)carbonyl]amino}-1 -phenyl-1 H-pyrrole-3- carboxylate

To Intermediate 7 (0.34 g, 1.29 mmol) was added dry DCM (7 mL), trans-4- methylcyclohexanecarbonyl chloride¹ (0.31 g, 1.94 mmol) and then triethylamine (0.45 g, 4.50 mmol). The reaction was stirred at room temperature, under a nitrogen atmosphere, for 1 hour, then partitioned between saturated sodium bicarbonate solution and ethyl acetate. The organic phase was washed with water, then 2N hydrochloric acid and then brine. The organics were dried over sodium sulphate and concentrated. The crude material was purified using a 40 g NH₂ SPE cartridge ISCO Companion Flash column eluting with a gradient of 0-30% EtOAc in cyclohexane to furnish the title compound. MS calcd for (C₂₁H₂₆N₂O₃ + H)⁺: 355 MS found (electrospray): (M+H)⁺ = 355 1. WO 2004/052885

Intermediate 9 Ethyl 4-[[(trans-4-methylcyclohexy^|)carbonyl](tetrahydro-3-furanyl)amino]-1 -phenyl- 1 H-pyrrole-3-carboxylate

To racemic 3-hydroxytetrahydrofuran (0.12 g, 1.4 mmol) was added dry DCM (3 ml_) and pyridine (0.13 g, 1.6 mmol). The mixture was cooled to -1O⁰C then triflic anhydride (0.39 g, 1.4 mmol) was added and stirring continued for 30mins, maintaining the temperature below O⁰C. The reaction was quenched with 2N hydrochloric acid (5 mL) and the mixture passed through a hydrophobic frit to give a DCM solution of the corresponding triflate. In a separate flask, to a dry THF (3.3 mL) solution of Intermediate 8 (165 mg, 0.46 mmol) at -78⁰C, under a nitrogen atmosphere, was added 0.5M potassium hexamethyldisilazide in toluene (1.21 mL, 0.61 mmol). The reaction was stirred at -78⁰C for 30mins the DCM solution of the triflate was added dropwise. The reaction was stirred at -78⁰C for 30 mins then slowly warmed to -1O⁰C and stirred for 30 mins. The reaction was quenched with 2N hydrochloric acid and extracted with ethyl acetate. The organic phase was washed with brine, dried over sodium sulphate and concentrated The crude material was purified using a 4Og silica ISCO Companion Flash column eluting with a gradient of 0-100% EtOAc in cyclohexane to furnish the title compound.

MS calcd for (C₂₅H₃₂N₂O₄ + H)⁺: 425 MS found (electrospray): (M+H)⁺ = 425

Intermediate 10 Ethyl 4-[(1 -methylethyl)amino]-1 -p -carboxylate hydrochloride

To Intermediate 4 (0.2 g, 0.54 mmol) was added 4M hydrogen chloride in 1 ,4-dioxane (2 mL). The reaction was stirred at room temperature over a weekend and then solvent removed to furnish the title compound. MS calcd for (C₁₆H₂₀N₂O₂ + H)⁺: 273 MS found (electrospray): (M+H)⁺ = 273

Alternative preparation of Intermediate 6

Ethyl 4-{1 -methylethyl^frans^-methylcyclohexyljcarbonyljamino}-! -phenyl-1 H- pyrrole-3-carboxylate

To Intermediate 10 (150 mg, 048 mmol) was added dry DCM (2.5 mL), triethylamine (0.122 g, 1.21 mmol) and frans-4-methylcyclohexanecarbonyl chloride¹ (0.177 g, 0.73 mmol). The reaction was stirred at 45⁰C, under a nitrogen atmosphere, for 16 hours. The reaction was cooled and partitioned between ethyl acetate and 2M hydrochloric acid. The organic phase was washed further with water, saturated sodium bicarbonate solution and brine. The organics were dried over sodium sulphate and concentrated. The crude product was purified using a 12 g silica ISCO Companion Flash column eluting with a gradient of 0-30% EtOAc in cyclohexane, then by dissolved in 1 ,4-dioxane and passed through a 5g NH₂ SPE and concentrated to furnish the title compound. MS calcd for (C₂₄H₃₂N₂O₃ + H)⁺: 397 MS found (electrospray): (M+H)⁺ = 397 1. WO 2004/052885

Intermediate 11

1 ,1 -Dimethylethyl N-(4-iodophenyl)glycinate

To 4-iodoaniline (20 g, 0.091 mol) was added dry THF (200 mL), DIPEA (12.4 g, 0.096 mol) and t-butylbromoacetate (18.7 g, 0.096 mol). The reaction was stirred at reflux for 16 hours. The reaction was cooled, partitioned between DCM and water, passed through a hydrophobic frit and the organic phase was concentrated. The crude material was purified by a 330 g silica ISCO Companion flash column eluted with 0-10% ethyl acetate in cyclohexane to furnish the title compound. MS calcd for (C₁₂H₁₆INO₂ + H)⁺: 334 MS found (electrospray): (M+H)⁺ = 334

Intermediate 12

2-(1 ,1 -Dimethylethyl) 4-ethyl 3-amino-1 -(4-iodophenyl)-1 H-pyrrole-2,4-dicarboxylate

To Intermediate 11 (21.8 g, 0.065 mol) was added dry toluene (300 ml_), DBU (20.9 g, 0.137 mol) and ethyl (ethoxymethylene)cyano acetate (12.2 g, 0.072 mol). The reaction was stirred at reflux, under a nitrogen atmosphere, over a weekend. The reaction was cooled, partitioned between DCM and saturated ammonium chloride, passed through a hydrophobic frit and the organic phase was concentrated. The crude product was purified by a 330 g silica ISCO Companion flash column eluted with 1-40% ethyl acetate in cyclohexane to furnish the title compound. MS calcd for (C₁₈H₂₁IN₂O₄ + H)⁺: 457 MS found (electrospray): (M+H)⁺ = 457

Intermediate 13

2-(1 ,1 -Dimethylethyl) 4-ethyl 1 -(4-iodophenyl)-3-[(1 -methylethyl)amino]-1 H-pyrrole-2,4- dicarboxylate

To Intermediate 12 (5.0 g, 0.011 mol) was added dry DCM (100 mL), acetic acid (2.6 g,

0.044 mol), 2-methoxypropene (3.16 g, 0.044 mol) and sodium triacetoxyborohydride (4.64 g, 0.022 mol). The reaction was stirred at room temperature, under a nitrogen atmosphere, for 24 hours. Further acetic acid (2.6 g, 0.044 mol), 2-methoxypropene (3.16 g, 0.044 mol) and sodium triacetoxyborohydride (4.64 g, 0.022 mol) were added and stirring continued for a further 24 hours. The reaction was quenched with saturated sodium bicarbonate solution, partitioned with DCM, passed through a hydrophobic frit and the organics were concentrated. The crude product was purified by a 330 g silica ISCO Companion flash column eluted with 5-30% ethyl acetate in cyclohexane to furnish the title compound contaminated with 25-30% of Intermediate 12.

MS calcd for (C₂₁H₂₇IN₂O₄ + H)⁺: 499 MS found (electrospray): (M+H)⁺ = 499

Intermediate 14 Ethyl 1 -(4-lodophenyl)-4-[[(trans-4-methylcyclohexyl)carbonyl](1 -methylethyl)amino]- 1 H-pyrrole-3-carboxylate

To Intermediate 13 (2.2 g, 4.42 mmol) was added 4M hydrogen chloride in 1 ,4-dioxane (20 mL). The reaction was stirred at room temperature over a weekend and then the solvent removed. To the residue was added dry DCM (30 mL), føns-4-methylcyclohexanecarbonyl chloride¹ (1.11 g, 6.9 mmol) and triethylamine (1.16 g, 11.5 mmol). The reaction was stirred at room temperature, under a nitrogen atmosphere for 30 mins. The reaction was quenched with saturated sodium bicarbonate solution and extracted with ethyl acetate. The organic phase was washed with water, followed by 2N hydrochloric acid, then brine, passed through a hydrophobic frit and concentrated. The crude product was purified by a 12O g silica ISCO Companion flash column eluting with 0-50% ethyl acetate in cyclohexane to furnish the title compound.

MS calcd for (C₂₄H_3IlN₂O₃ + H)⁺: 523 MS found (electrospray): (M+H)⁺ = 523 1. WO 2004/052885

Intermediate 15

Ethyl 4-[[(trans-4-methylcyclohexyl)carbonyl](1 -methylethyl)amino]-1 -{4-

[(trimethylsilyI)ethynyl]phenyl}-1H-pyrroIe-3-carboxyIate

To a degassed THF (2.5 mL) solution of Intermediate 14 (0.5 g, 0.96 mmol) was added copper (I) iodide (9.1 mg, 0.05 mmol), triethylamine (0.5 mL), trimethylsilyl acetylene (169 mg, 1.7 mmol) and palladium bis(triphenylphosphine) dichloride (33 mg, 0.05 mmol). The reaction was stirred at 55⁰C, under a nitrogen atmosphere, for 1.5 hours. The reaction was cooled, diluted with DCM, filtered and concentrated. The crude product was purified by an 80 g silica ISCO Companion flash column eluted with 0-70% ethyl acetate in cyclohexane to furnish the title compound.

MS calcd for (C₂₉H₄₀N₂O₃Si + H)⁺: 493

MS found (electrospray): (M+H)⁺ = 493

Intermediate 16

Ethyl 1 -(4-ethynylphenyI)-4-[[(trans-4-methylcyclohexyl)carbonyl](1 - methylethyl)amino]-1H-pyrrole-3-carboxylate

To Intermediate 15 (0.36 g, 0.73 mmol) was added ethanol (7 mL) and potassium carbonate (50 mg, 0.36 mmol). The reaction was stirred at room temperature for 3 hours. The solvent was removed and the residue partitioned between DCM and saturated sodium bicarbonate solution, passed through a hydrophobic frit, then the organic phase was concentrated to furnish the title compound. MS calcd for (C₂₆H₃₂N₂O₃ + H)⁺: 421 MS found (electrospray): (M+H)⁺ = 421

Example 1 4-{1 -MethylethylKfrans^πmethylcyclohexyOcarbonyllaminoH -phenyl-1 H-pyrrole-3- carboxylic acid

To a solution of Intermediate 6 (30 mg, 0.08 mmol) in THF (1 mL), was added ethanol (1 mL) and 2M lithium hydroxide (1 mL). The reaction was stirred at 6O⁰C for 16 hours. The reaction was cooled, partitioned between DCM and 2N HCI and passed through a hydrophobic frit. The organic phase was concentrated and purified by MDAP HPLC to furnish the title compound. MS calcd for (C₂₂H₂₈N₂O₃ + H)⁺: 369 MS found (electrospray): (M+H)⁺ = 369 ¹H NMR (CD₃OD) δ 7.91 (1H, d), 7.58 (2H, d), 7.52 (2H, t), 7.38 (1H, t), 7.31 (1H, d), 4.87 (1 H, m partially hidden by solvent), 2.30 (1 H, m), 1.84-1.50 (5H, m), 1.42-1.23 (2H, m), 1.15 (3H, d), 0.96 (3H, d), 0.78 (3H, d), 0.77-0.56 (2H, m)

Example 2 4-[[(trans-4-MethyIcyclohexyl)carbonyl](tetrahydro-3-furanyl)amino]-1-phenyl-1H- pyrrole-3-carboxylic acid

To a solution of Intermediate 9 (36 mg, 0.08 mmol) in THF (1 ml_), was added ethanol (1 mL) and 2M lithium hydroxide (1 mL). The reaction was stirred at 6O⁰C for 16 hours then reflux for 3 hours. The reaction was cooled, partitioned between DCM and 2N HC) and passed through a hydrophobic frit. The organic phase was concentrated to furnish the title compound.

MS calcd for (C₂₃H₂₈N₂O₄ + H)⁺: 397

MS found (electrospray): (M+H)⁺ = 397 ¹H NMR (CD₃OD) seem as a mixture rotamers δ 7.92 (1 H, dd), 7.58 (2H, m), 7.52 (2H, t),

7.44 (1 H, dd), 7.39 (1 H, m), 5.08 (1 H, m), 4.02 (0.5H dd), 3.79 (0.5H, dd), 3.77-54 (3H, m partially obsc ured by THF solvent peak), 2.28 (1.5H, m), 2.02 (1H, m), 1.87 (0.5H, m partiallyobscured by THF solvent peak), 1.80-1.22 (7H, br. m), 0.78 (3H, d), 0.77-0.58 (2H, m) carboxylic acid proton exchanged with solvent.

Example 3

1 -(4-Iodophenyl)-4-[[(trans-4-methylcyclohexyl)carbonyl](1 -methylethyl)amino]-1 H- pyrrole-3-carboxylic acid

To a solution of Intermediate 14 (10 mg, 0.02 mmol) in THF (1 ml_), was added ethanol (1 mL) and 2M lithium hydroxide (1 ml_). The reaction was stirred at 7O⁰C for 24 hours. The reaction was cooled, neutralised with 2N hydrochloric acid (1 mL), partitioned between DCM and water, passed through a hydrophobic frit and the organic phase was concentrated to furnish the title compound. MS calcd for (C₂₂H₂₇IN₂O₃ + H)⁺: 495 MS found (electrospray): (M+H)⁺ = 495

¹H NMR (CD₃OD) δ 7.92 (1 H, s), 7.85 (2H, d), 7.40 (2H, d), 7.32 (1H₁ d), 4.90 (1 H, m, partially hidden by solvent), 2.28 (1 H, m), 1.98-1.22 (7H, br), 1.15 (3H, d), 0.95 (3H, d), 0.88 (3H, d), 0.65 (2H, m) carboxylic acid proton exchanged with solvent

Example 4

1 -(4-Ethynylphenyl)-4-[[(trans-4-methylcyclohexyl)carbonyI](1 -methyJethyl)amino]-1 H- pyrrole-3-carboxylic acid

To a solution of Intermediate 16 (10 mg, 0.02 mmol) in THF (1 mL), was added ethanol (1 mL) and 2M lithium hydroxide (1 mL). The reaction was stirred at 7O⁰C for 24 hours. The reaction was cooled, neutralised with 2N hydrochloric acid (1 mL), partitioned between DCM and water, passed through a hydrophobic frit and the organic phase was concentrated to furnish the title compound.

MS calcd for (C₂₄H₂₈N₂O₃ + H)⁺: 393

MS found (electrospray): (M+H)^÷= 393

¹H NMR (CD₃OD) δ 7.86 (1H, d), 7.58 (4H, s), 7.30 (1H, d), 4.90 (1H, m, partially hidden by solvent), 3.58 (1 H, s), 2.30 (1H, m), 1.90 (1H, br, partially hidden by solvent) , 1.78-1.50 (4H, br), 1.43-1.25 (2H, br), 1.18 (3H, d), 0.98 (3H, d), 0.80 (3H, d), 0.68 (2H, m) carboxylic acid proton exchanged with solvent

The chemical entities according to the invention may be formulated for administration in any convenient way, and the invention therefore also includes within its scope pharmaceutical compositions for use in therapy, comprising a compound of formula (I) or a physiologically acceptable salt or solvate thereof in admixture with one or more physiologically acceptable diluents or carriers.

The chemical entities of the present invention can be administered by different routes including intravenous, intraperitoneal, subcutaneous, intramuscular, oral, topical, transdermal, or transmucosal administration. For systemic administration, oral administration is preferred. For oral administration, for example, the chemical entities can be formulated into conventional oral dosage forms such as capsules, tablets and liquid preparations such as syrups, elixirs and concentrated drops.

Alternatively, injection (parenteral administration) may be used, e.g., intramuscular, intravenous, intraperitoneal, and subcutaneous. For injection, the chemical entities of the invention are formulated in liquid solutions, preferably, in physiologically compatible buffers or solutions, such as saline solution, Hank's solution, or Ringer's solution. In addition, the chemical entities may be formulated in solid form and redissolved or suspended immediately prior to use. Lyophilized forms can also be produced.

Systemic administration can also be by transmucosal or transdermal means. For transmucosal or transdermal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art, and include, for example, for transmucosal administration, bile salts and fusidic acid derivatives. In addition, detergents may be used to facilitate permeation. Transmucosal administration, for example, may be through nasal sprays, rectal suppositories, or vaginal suppositories.

For topical administration, the compounds of the invention can be formulated into ointments, salves, gels, or creams, as is generally known in the art.

The amounts of various chemical entities to be administered can be determined by standard procedures taking into account factors such as the compound (IC₅₀) potency, (EC₅₀) efficacy, and the biological half-life (of the chemical entity), the age, size and weight of the patient, and the disease or disorder associated with the patient. The importance of these and other factors to be considered are known to those of ordinary skill in the art.

Amounts administered also depend on the routes of administration and the degree of oral bioavailability. For example, for chemical entities with low oral bioavailability, relatively higher doses will have to be administered. Oral administration is a preferred method of administration of the present chemical entities.

Preferably the composition is in unit dosage form. For oral application, for example, a tablet, or capsule may be administered, for nasal application, a metered aerosol dose may be administered, for transdermal application, a topical formulation or patch may be administered and for transmucosal delivery, a buccal patch may be administered. In each case, dosing is such that the patient may administer a single dose.

Each dosage unit for oral administration contains suitably from 0.01 to 500 mg/Kg, and preferably from 0.1 to 50 mg/Kg, of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, calculated as the free base. The daily dosage for parenteral, nasal, oral inhalation, transmucosal or transdermal routes contains suitably from 0.01 mg to 100 mg/Kg, of a compound of Formula(l). A topical formulation contains suitably 0.01 to 5.0% of a compound of Formula (I). The active ingredient may be administered from 1 to 6 times per day, preferably once, sufficient to exhibit the desired activity, as is readily apparent to one skilled in the art.

Chemical entities of Formula (I) which are active when given orally can be formulated as syrups, tablets, capsules and lozenges. A syrup formulation will generally consist of a suspension or solution of the compound or salt in a liquid carrier for example, ethanol, peanut oil. olive oil, glycerine or water with a flavoring or coloring agent. Where the composition is in the form of a tablet, any pharmaceutical carrier routinely used for preparing solid formulations may be used. Examples of such carriers include magnesium stearate, terra alba, talc, gelatin, acacia, stearic acid, starch, lactose and sucrose. Where the composition is in the form of a capsule, any routine encapsulation is suitable, for example using the aforementioned carriers in a hard gelatin capsule shell. Where the composition is in the form of a soft gelatin shell capsule any pharmaceutical carrier routinely used for preparing dispersions or suspensions may be considered, for example aqueous gums, celluloses, silicates or oils, and are incorporated in a soft gelatin capsule shell.

Typical parenteral compositions consist of a solution or suspension of a compound or salt in a sterile aqueous or non-aqueous carrier optionally containing a parenterally acceptable oil, for example polyethylene glycol, polyvinylpyrrolidone, lecithin, arachis oil or sesame oil.

Typical compositions for inhalation are in the form of a solution, suspension or emulsion that may be administered as a dry powder or in the form of an aerosol using a conventional non- CFC propellant such as 1 ,1 ,1 ,2-tetrafluoroethane or 1 ,1 ,1 , 2,3,3,3-heptafluoropropane.

A typical suppository formulation comprises a compound of Formula (I) or a pharmaceutically acceptable salt thereof which is active when administered in this way, with a binding and/or lubricating agent, for example polymeric glycols, gelatins, cocoa-butter or other low melting vegetable waxes or fats or their synthetic analogs.

Typical dermal and transdermal formulations comprise a conventional aqueous or non- aqueous vehicle, for example a cream, ointment, lotion or paste or are in the form of a medicated plaster, patch or membrane.

No unacceptable toxicological effects are expected when compounds of the present invention are administered in accordance with the present invention.

ASSAY

The potential for chemical entities of the invention to inhibit NS5B wildtype HCV polymerase activity may be demonstrated, for example, using the following in vitro assay:

In Vitro Detection of inhibitors of HCV RNA-dependent RNA Polymerase Activity

Incorporation of [³³P]-GMP into RNA was followed by absorption of the biotin labelled RNA polymer by streptavidin containing SPA beads. A synthetic template consisting of biotinylated 13mer-oligoG hybridised to polyrC was used as a homopolymer substrate.

Reaction Conditions were 0.5 μM [³³P]-GTP (20 Ci/mMol), 1 mM Dithiothreitol, 20 mM MgCI₂, 5mM MnCI₂, 20 mM Tris-HCI, pH7.5, 1.6 μg/mL polyC/0.256 μM biotinylated oligoG13, 10% glycerol, 0.01% NP-40, 0.2 u/μL RNasin and 50 mM NaCI.

HCV RNA Polymerase (Recombinant full-length NS5B (Lohmann et al, J. Virol. 71 (11), 1997, 8416 'Biochemical properties of hepatitis C virus NS5B RNA-dependent RNA polymerase and identification of amino acid sequence motifs essential for enzymatic activity') expressed in baculovirus and purified to homogeneity) was added to 4 nM final concentration.

5x concentrated assay buffer mix was prepared using 1 M MnCI₂ (0.25 ml_), glycerol (2.5mL), 10% NP-40 (0.025 mL) and Water (7.225 ml_), Total 10 mL.

2x concentrated enzyme buffer contained 1M-Tris-HCI, pH7.5 (0.4 mL), 5M NaCI (0.2 mL), 1 M-MgCl₂ (0.4 mL), glycerol (1 mL), 10% NP-40 (10 μl_), 1M DTT (20 μL) and water (7.97 mL), Tote/ 1O mL

Substrate Mix was prepared using 5x Concentrated assay Buffer mix (4μL), [³³P]-GTP (10 μCi/μL, 0.02μL), 25 μM GTP (0.4 μL), 40 u/μL RNasin (0.1 μL), 20 μg/mL polyrC/biotinylated- oligorG (1.6 μL), and Water (3.94 μL), Total 10 μL.

Enzyme Mix was prepared by adding 1 mg/mL full-length NS5B polymerase (1.5 μL) to 2.81 mL 2x-concentrated enzyme buffer. The Assay was set up using compound (1μL), Substrate Mix (10 μl_), and Enzyme Mix (added last to start reaction) (10 μL), Total 21 μL.

The reaction was performed in a U-bottomed, white, 96-well plate. The reaction was mixed on a plate-shaker, after addition of the Enzyme, and incubated for 1h at 22°C. After this time, the reaction was stopped by addition of 40 μL 1.875 mg/mL streptavidin SPA beads in 0.1 M EDTA. The beads were incubated with the reaction mixture for 1h at 22°C after which 120 μL 0.1 M EDTA in PBS was added. The plate was sealed, mixed centrifuged and incorporated radioactivity determined by counting in a Trilux (Wallac) or Topcount (Packard) Scintillation Counter.

After subtraction of background levels without enzyme, any reduction in the amount of radioactivity incorporated in the presence of a compound, compared to that in the absence, was taken as a measure of the level of inhibition. Ten concentrations of compounds were tested in three- or fivefold dilutions. From the counts, percentage of inhibition at highest concentration tested or IC₅₀S for the compounds were calculated using Grafit3, Grafit4 or Grafitδ software packages or a data evaluation macro for Excel based on XLFit software (IDBS).

The exemplified compounds have IC₅₀ values of <35μM. In another aspect, compounds have an IC₅₀ of <5μM; in yet another aspect, compounds have an IC₅₀ of <1 μM. Accordingly, the compounds of the invention are of potential therapeutic benefit in the treatment and prophylaxis of HCV.

The pharmaceutical compositions according to the invention may also be used in combination with other therapeutic agents, for example immune therapies (eg. Interferon, such as Interferon alfa-2a (Roferon-A; Hoffmann-La Roche), inteferon alpha-2b (Intron-A; Schering-Plough), interferon alfacon-1 (Infergen; Intermune), peginterferon alpha-2b (Peg- Intron; Schering-Plough) or peginterferon alpha-2a (Pegasys; Hoffmann-La Roche)), therapeutic vaccines, antifibrotic agents, anti-inflammatory agents such as corticosteroids or NSAIDs, bronchodilators such as beta-2 adrenergic agonists and xanthines (e.g. theophylline), mucolytic agents, anti-muscarinics, anti-leukotrienes, inhibitors of cell adhesion (e.g. ICAM antagonists), anti-oxidants (eg N-acetylcysteine), cytokine agonists, cytokine antagonists, lung surfactants and/or antimicrobial and anti-viral agents (eg ribavirin and amantidine). The compositions according to the invention may also be used in combination with gene replacement therapy.

The invention thus provides, in a further, aspect, a combination comprising at least one compound of formula (I) or a physiologically acceptable salt or solvate thereof together with at least one other therapeutically active agent, especially interferon and/or ribavirin. The combinations referred to above may conveniently be presented for use in the form of a pharmaceutical formulation and thus pharmaceutical formulations comprising a combination as defined above together with a pharmaceutically acceptable carrier thereof represent a further aspect of the invention.

The individual components of such combinations may be administered either sequentially or simultaneously in separate or combined pharmaceutical formulations. Appropriate doses of known therapeutic agents will be readily appreciated by those skilled in the art.

All publications, including but not limited to patents and patent applications cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference as though fully set forth.

Claims

1. At least one chemical entity ds of Formula (I) :

wherein:

A represents hydroxy;

R¹ represents aryl, heteroaryl bonded through a ring carbon atom, or heterocyclyl bonded through a ring carbon atom, each of which may be optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR^βR^c, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R^D, -NR^ECO₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, -CF₃, -OCF₃, NR^ESO₂R°, phenyl and heterocyclyl, wherein the -C^alkyl substituent itself may be optionally substituted by one or more substituents selected from -Cs^cycloalkyl, halo, -NR^BR^C, -C(O)NR⁶R⁰, -NR^EC(O)R°, -SR^A, -SO₂R⁰, OR^A, oxo, phenyl, heteroaryl or heterocyclyl; or R¹ represents -Ci_-6alkyl or -C_5-9cycloalkyl;

R² represents phenyl substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^G, -NR^EC(O)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R² represents -(CH₂)_πC5-7cycloalkyl optionally substituted on the cycloalkyl by one or more substitutents selected from -C_1-6alkyl, =CH(CH₂)_tH, -0R^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR⁶R⁰, -NR^EC(O)R^D, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, and heterocyclyl, or wherein two substituents may together form a C_1-2alkylene bridge substituent;

t represents 0, 1 , 2, 3 or 4;

n represents O or 1 ;

R³ represents heterocyclyl or heteroaryl; or phenyl optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR⁸R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR⁶R⁰, -NR^EC(0)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R³ represents -C_1-6alkyl optionally substituted by one or more substituents selected from -C_1-6alkyl, -OR^A, -SR^A, -C(O)NR⁸R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR⁶R⁰, -NR^EC(0)R°, -NR^EC0₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, phenyl, heteroaryl and heterocyclyl; R⁴ represents hydrogen;

R^A represents hydrogen, -C^alkyl, arylalkyl, heteroarylalkyl, aryl, heterocyclyl or heteroaryl;

R^D is selected from the group consisting of -C_1-6alkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, and heteroarylalkyl;

R^E represents hydrogen or -C_1-6alkyl;

R^F and R^G are independently selected from the group consisting of hydrogen, -Ci_-6alkyl, aryl, heteroaryl, arylalkyl, and heteroarylalkyl; or R^F and R^G together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

and salts, solvates and esters thereof.

2. At least one chemical entity as claimed in claim 1 chosen compounds of Formula (I) selected from the group consisting of:

4-{1 -methylethy^frans-^methylcyclohexyOcarbonylJamino}-! -phenyl-1 /-/-pyrrole-3-carboxylic acid; 4-[[(trans-4-methylcyclohexyl)carbonyl](tetrahydro-3-furanyl)amino]-1-phenyl-1 H-pyrrole-3- carboxylic acid;

1 -(4-iodophenyl)-4-[[(trans-4-methylcyclohexyl)carbonyl](1 -methylethyl)amino]-1 H-pyrrole-3- carboxylic acid; and

3. A method of treating or preventing viral infection which comprises administering to a subject in need thereof, an effective amount of at least one chemical entity chosen from compounds of Formula (I)

wherein:

A represents hydroxy;

R¹ represents aryl, heteroaryl bonded through a ring carbon atom, or heterocyclyl bonded through a ring carbon atom, each of which may be optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, -CF₃, -OCF₃, NR^ESO₂R°, phenyl and heterocyclyl, wherein the -C_halky! substituent itself may be optionally substituted by one or more substituents selected from -C₅.₉cycloalkyl, halo, -NR^BR^G, -C(O)NR⁶R⁰, -NR^EC(O)R°, -SR^A, -SO₂R⁰, 0R^A, oxo, phenyl, heteroaryl or heterocyclyl; or R¹ represents -C_1-6alkyl or -C_5-9cycloalkyl;

R² represents phenyl substituted by one or more substituents selected from -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR⁶R⁰, -NR^EC(O)R^D, -NR^ECO₂R°,

-NR^EC(0)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R² represents

-(CH₂)_nC_5-7cycloalkyl optionally substituted on the cycloalkyl by one or more substitutents selected from -C_1-6alkyl, =CH(CH₂)_tH, -0R^A, -SR^A, -C(O)NR⁸R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰,

-NR⁶R⁰, -NR^EC(O)R°, -NR^ECO₂R°, -NR^EC(0)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, and heterocyclyl, or wherein two substituents may together form a C_1-2alkylene bridge substituent;

t represents 0, 1 , 2, 3 or 4;

n represents O or 1 ;

R³ represents heterocyclyl or heteroaryl; or phenyl optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR°, -NR^EC(0)R°, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R³ represents -C_1-6alkyl optionally substituted by one or more substituents selected from -C_1-6alkyl, -0R^A, -SR^A, -C(O)NR⁸R⁰, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR⁶R⁰, -NR^EC(O)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -S0₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, phenyl, heteroaryl and heterocyclyl;

R⁴ represents hydrogen; R^A represents hydrogen, -C_halky!, arylalkyl, heteroarylalkyl, aryl, heterocyclyl or heteroaryl;

R^B and R^G independently represent hydrogen, -C_1-6alkyl, aryl, heterocyclyl or heteroaryl; or R^B and R^c together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

R^E represents hydrogen or -C_1-6alkyl;

R^F and R^G are independently selected from the group consisting of hydrogen, -C_1-6alkyl, aryl, heteroaryl, arylalkyl, and heteroarylalkyl; or R^F and R^G together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group; and salts, solvates and esters thereof.

4. A method as claimed in claim 3 which involves inhibiting HCV replication.

5. A method as claimed in claim 3 in which the chemical entity is administered in an oral dosage form.

6. At least one chemical entity ds of Formula (I)

wherein: A represents hydroxy;

R¹ represents aryl, heteroaryl bonded through a ring carbon atom, or heterocyclyl bonded through a ring carbon atom, each of which may be optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R^D, -NR^ECO₂R°, -NR^EC(O)NR^FR^G -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, -CF₃, -OCF₃, NR^ESO₂R^D, phenyl and heterocyclyl, wherein the -C_1-6alkyl substituent itself may be optionally substituted by one or more substituents selected from -C_5-9cycloalkyl, halo, -NR^BR^C, -C(O)NR^BR^C, -NR^EC(O)R^D, -SR^A, -SO₂R⁰, OR^A, oxo, phenyl, heteroaryl or heterocyclyl; or R¹ represents -C_1-6alkyl or -Cs^cycloalkyl; R² represents phenyl substituted by one or more substituents selected from -C^alkyl, halo, -OR^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR⁵C(O)R⁰, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R² represents -(CH₂)_nC_5-7cycloalkyl optionally substituted on the cycloalkyl by one or more substitutents selected from -C_1-6alkyl, =CH(CH₂),H, -0R^A, -SR^A, -C(O)NR^BR^C, -C(O)R⁰, -CO₂H, -CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^ECO₂R^D, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, and heterocyclyl, or wherein two substituents may together form a C_1-2alkylene bridge substituent;

t represents 0, 1 , 2, 3 or 4;

n represents O or 1 ;

R³ represents heterocyclyl or heteroaryl; or phenyl optionally substituted by one or more substituents selected from -C_1-6alkyl, halo, -0R^A, -SR^A, -C(O)NR⁶R⁰, -C(O)R⁰, -CO₂H,

-CO₂R⁰, -NR^BR^C, -NR^EC(O)R°, -NR^EC0₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, nitro, cyano, and heterocyclyl; or R³ represents -C_1-6alkyl optionally substituted by one or more substituents selected from -C_1-6alkyl, -0R^A, -SR^A, -C(0)NR^BR^G, -C(O)R⁰, -CO₂H,

-CO₂R⁰, -NR^BR^C, -NR^EC(0)R°, -NR^ECO₂R°, -NR^EC(O)NR^FR^G, -SO₂NR^FR^G, -SO₂R⁰, fluoro, nitro, cyano, oxo, phenyl, heteroaryl and heterocyclyl;

R⁴ represents hydrogen;

R^A represents hydrogen, -Ci_-6alkyl, arylalkyl, heteroarylalkyl, aryl, heterocyclyl or heteroaryl;

R^B and R^c independently represent hydrogen, -C^alkyl, aryl, heterocyclyl or heteroaryl; or R^B and R^c together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

R^E represents hydrogen or -Ci_-6alkyl;

R^F and R^G are independently selected from the group consisting of hydrogen, -C_1-6alkyl, aryl, heteroaryl, arylalkyl, and heteroarylalkyl; or R^F and R^G together with the nitrogen atom to which they are attached form a 5 or 6 membered saturated cyclic group;

and salts, solvates and esters thereof. for use in medical therapy.

7. A compound as claimed in claim 6 wherein the medical therapy is the treatment of viral infection.

8. A compound as claimed in claim 7 wherein the viral infection is HCV.

9. A pharmaceutical formulation comprising at least one chemical entity chosen from compounds of Formula (I) and pharmaceutically acceptable salts, solvates and esters thereof as defined in claim 1 in conjunction with at least one pharmaceutically acceptable diluent or carrier.

10. A process for the preparation of a compound of Formula (I) as defined in claim 1 , comprising treatment of a compound of Formula (II)

in which A is an alkoxy, benzyloxy or silyloxy group and R¹, R², R³ and R⁴ are as defined above for Formula (I), with a base.

11. A process as claimed in claim 10 in which A is ethoxy.

12. Use of at least one chemical entity chosen from compounds of Formula (I) and pharmaceutically acceptable salts, solvates and esters thereof as claimed in claim 1 , in the manufacture of a medicament for the treatment and/or prophylaxis of viral infection.

13. Use as claimed in claim 12 wherein the viral infection is HCV.

14. A combination comprising at least one chemical entity of Formula (I) as defined in Claim 1 , together with at least one other therapeutically active agent.

15. A combination as claimed in Claim 14, wherein the other therapeutically active agent is selected from Interferon, ribavirin and/or an additional anti-HCV agent.