WO2003042206A1

WO2003042206A1 - Pyridinone and pyrimidinone compounds

Info

Publication number: WO2003042206A1
Application number: PCT/EP2002/012504
Authority: WO
Inventors: Colin Andrew Leach; Stephen Allan Smith
Original assignee: Smithkline Beecham P.L.C.
Priority date: 2001-11-10
Filing date: 2002-11-08
Publication date: 2003-05-22
Also published as: GB0127139D0

Abstract

Pyrimidone and pyridone compounds of the formula (I), are inhibitors of the enzyme Lp-PLA2 and are of use in therapy, in particular for treating atherosclerosis.

Description

PYRIDINONE AND PYRIMIDINONE COMPOUNDS

The present invention relates to certain novel pyrimidone and pyridone compounds, processes for their preparation, intermediates useful in their preparation, pharmaceutical compositions containing them and their use in therapy, in particular in the treatment of atherosclerosis.

WO 95/00649 (SmithKline Beecham pic) describes the phospholipase A2 enzyme Lipoprotein Associated Phospholipase A2 (Lp-PLA2), the sequence, isolation and purification thereof, isolated nucleic acids encoding the enzyme, and recombinant host cells transformed with DNA encoding the enzyme. Suggested therapeutic uses for inhibitors of the enzyme included atherosclerosis, diabetes, rheumatoid arthritis, stroke, myocardial infarction, reperfusion injury and acute and chronic inflammation. A subsequent publication from the same group further describes this enzyme (Tew D et al, Arterioscler Thromb Vas Biol 1996:16;591-9) wherein it is referred to as LDL-PLA2. A later patent application (WO 95/09921, Icos Corporation) and a related publication in Nature (Tjoelker et al, vol 374, 6 April 1995, 549) describe the enzyme PAF-AH which has essentially the same sequence as Lp-PLA2 and suggest that it may have potential as a therapeutic protein for regulating pathological inflammatory events.

It has been shown that Lp-PLA2 is responsible for the conversion of phosphatidylcholine to lysophosphatidylcholine, during the conversion of low density lipoprotein (LDL) to its oxidised form. The enzyme is known to hydrolyse the sn-2 ester of the oxidised phosphatidylcholine to give lysophosphatidylcholine and an oxidatively modified fatty acid. Both products of Lp-PLA2 action are biologically active with lysophosphatidylcholine, in particular having several pro-atherogenic activities ascribed to it including monocyte chemotaxis and induction of endothelial dysfunction, both of which facilitate monocyte-derived macrophage accumulation within the artery wall. Inhibition of the Lp-PLA2 enzyme would therefore be expected to stop the build up of these macrophage enriched lesions (by inhibition of the formation of lysophosphatidylcholine and oxidised free fatty acids) and so be useful in the treatment of atherosclerosis.

The increased lysophosphatidylcholine content of oxidatively modified LDL is also thought to be responsible for the endothelial dysfunction observed in patients with atherosclerosis. Inhibitors of Lp-PLA2 could therefore prove beneficial in the treatment of this phenomenon. An Lp-PLA2 inhibitor could also find utility in other disease states that exhibit endothelial dysfunction including diabetes, hypertension, angina pectoris and after ischaemia and reperfusion.

In addition, Lp-PLA2 inhibitors may also have a general application in any disorder that involves activated monocytes, macrophages or lymphocytes, as all of these cell types express Lp-PLA₂. Examples of such disorders include psoriasis. Furthermore, L -PLA2 inhibitors may also have a general application in any disorder that involves lipid oxidation in conjunction with Lp-PLA2 activity to produce the two injurious products, lysophosphatidylcholine and oxidatively modified fatty acids. Such conditions include the aforementioned conditions atherosclerosis, diabetes, rheumatoid arthritis, stroke, myocardial infarction, ischaemia, reperfusion injury and acute and chronic inflammation.

Patent applications WO 96/12963, WO 96/13484, WO 96/19451, WO 97/02242, WO 97/217675, WO 97/217676, WO 96/41098, and WO 97/41099 (SmithKline Beecham pic) disclose ter alia various series of 4-thionyl/sulfinyl/sulfonyl azetidinone compounds which are inhibitors of the enzyme Lp-PLA2- These are irreversible, acylating inhibitors (Tew et al, Biochemistry, 37, 10087, 1998).

A further class of compounds has now been identified which are non-acylating inhibitors of the enzyme Lp-PLA₂. Thus, WO 99/24420,WO 00/10980, WO 00/66566, WO 00/66567 and WO 00/68208 (SmithKline Beecham pic) disclose a class of pyrimidone compounds typically having an l-N-(biphenyl)acetamide substituent on the pyrimidone. We have now found a new class of pyrimidone and pyridone compounds having good activity as inhibitors of the enzyme Lp-PLA2 in which the typical biphenyl substituent is replaced by alkylenephenyl and related groups.

Accordingly, the present invention provides a compound of formula (I):

(I) in which:

R .1¹ is an aryl group, optionally substituted by 1, 2, 3 or 4 substituents which may

R^ is hydrogen, halogen, Cπ _3)alkyl, or hydroxyCπ _3)alkyl; or

R^ and R^ together with the ring carbon atoms to which they are attached form a fused 5-or 6-membered carbocyclic ring; or

R² and R-⁵ together with the ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring ring optionally substituted by 1, 2, 3 or 4 substituents which may be the same or different selected from halogen, Cπ _4)alkyl, cyano, Cπ _4)alkoxy or Cπ -4)alkylthio, or mono to perffuoro-Cπ -4)alkyl);

R4 is hydrogen, C^.g-_jalkyl which may be unsubstituted or substituted by 1, 2 or 3 substituents selected from hydroxy, halogen, OR⁷, COR⁷, carboxy, COOR⁷, CONR⁹R¹⁰, NR⁹R¹⁰, NR⁷COR⁸, mono- or di-(hydroxyC(₁_6)alkyl)amino and N-hydroxyC( \ _6)alkyl-N-Cπ _6)alkylamino ; or

R4 is Het-C(Q-4)alkyl in which Het is a 5- to 7- membered heterocyclyl ring comprising N and optionally O or S, and in which N may be substituted by COR⁷, COOR⁷, CONR⁹R¹⁰, or C(i_6)al yl optionally substituted by 1, 2 or 3 substituents selected from hydroxy, halogen, OR⁷, COR⁷, carboxy, COOR⁷, CONR⁹R¹⁰ and NR⁹RlO_? for instance, piperidin-4-yl, pyrrolidin-3-yl;

R5 is (CH2)p wherein p is 2 to 12;

R6 is an aryl or a heteroaryl ring which is further optionally substituted by 1, 2, 3 or 4 substituents which may be the same or different selected from Cπ _6)alkyl, CQ_ 6)alkoxy, Cπ _g)alkylthio, Cπ _6)alkylsulfonyl, arylCπ _6)alkoxy, hydroxy, halogen, CN, COR⁷, carboxy, COOR⁷, CONR⁹R¹⁰, NR⁷COR⁸, SO₂NR⁹R¹⁰, NR⁷SO₂R⁸, NR⁹R¹⁰, mono to perfluoro-Cπ _4)alkyl and mono to perfluoro-C(i_4)alkoxy, or C(5_ιo)alkyl;

R⁷ and R⁸ are independently hydrogen or C(i_i2)^alky for instance C(i_4)alkyl (e.g. methyl or ethyl); R⁹ and RlO which may be the same or different is each selected from hydrogen, or Cπ _i2)alkyl, or R⁹ and R^iυ together with the nitrogen to which they are attached form a 5- to 7 membered ring optionally containing one or more further heteroatoms selected from oxygen, nitrogen and sulphur, and optionally substituted by one or two substituents selected from hydroxy, oxo, Cπ _4)alkyl, Cπ -4)alkylcarboxy, aryl, e.g. phenyl, or aralkyl, e.g benzyl, for instance morpholine or piperazine;

X is CH2S or (CH2)_n where n is 2 or 3; and

Y is CH or N.

In one aspect the aryl group of R! may be phenyl or naphthyl. Preferably, Rl is phenyl optionally substituted by halogen, Cπ _6)alkyl, trifluoromethyl, Cπ .g^alkoxy, preferably, from 1 to 3 fluoro, more preferably, 2,3-difluoro.

In another aspect R^ may be methyl, ethyl, or trifluoroethyl when R^ is hydrogen.

In another aspect R^ may be methyl when R^ is methyl.

L another aspect R^ and R^ together with the ring carbon atoms to which they are attached may form a fused 5-membered carbocyclic ring, or a fused benzo, pyrido, pyrazolo or thieno ring. Preferably, R^ and R-5 together with the ring carbon atoms to which they are attached form a fused 5-membered carbocyclic ring or a fused benzo, pyrido, thieno or pyrazolo ring, more preferably a fused benzo ring.

In another aspect R^ may be hydrogen, methyl, 2-(diethylamino)ethyl, 2-(piperidin-l- yl)ethyl, 2-(pyrrolidin-l-yl)ethyl, 1-methyl-piperidinyl, l-ethyl-piperidin-4-yl, 1-ethyl- pyrrolidin-2-ylmethyl or l-(2-methoxyethyl)piρeridin-4-yl. Preferably R^ is 2- (diethylamino)ethyl, l-ethyl-piperidin-4-yl or l-(2-methoxyethyl)piperidin-4-yl.

In another aspect R^ is (CH2) wherein p is 3 to 8.

In a further aspect R^ may be phenyl optionally substituted by halogen, or trifluoromethyl, preferably at the 4-position, or ethyl. Preferably, R^ is phenyl substituted by trifluoromethyl at the 4-position.

Preferably X is CH2S or (CH₂)₂, particularly CH₂S

Preferably Y is CH.

It will be appreciated that compounds of the present invention may comprise one or more chiral centres so that stereoisomers may be formed. The present invention encompasses all stereoisomers of the compounds of formula (T) including geometric isomers and optical isomers (eg. diastereoisomers and enantiomers) whether as individual stereoisomers isolated such as to be substantially free of the other stereoisomers (ie. pure) or as mixtures thereof including racemic modifications. An individual stereoisomer isolated such as to be substantially free of other stereoisomer (ie. pure) will preferably be isolated such that less than 10% preferably less than 1% especially less than 0.1% of the other stereoisomers is present.

Certain compounds of formula (I) may exist in one of several tautomeric forms. It will be understood that the present invention encompasses all tautomers of the compounds of formula (I) whether as individual tautomers or as mixtures thereof.

It will be appreciated that in some instances, compounds of the present invention may include a basic function such as an amino group as a substituent. Such basic functions may be used to form acid addition salts, in particular pharmaceutically acceptable salts. Pharmaceutically acceptable salts include those described by Berge, Bighley, and Monkhouse, J. Pharm. Set, 1977, 66, 1-19. Such salts may be formed from inorganic and organic acids. Representative examples thereof include maleic, fumaric, benzoic, ascorbic, pamoic, succinic, bismethylenesalicylic, methanesulfonic, ethanedisulfonic, acetic, propionic, tartaric, salicylic, citric, gluconic, aspartic, stearic, palmitic, itaconic, glycolic, p-aminobenzoic, glutamic, taurocholic acid, benzenesulfonic, p-toluenesulfonic, hydrochloric, hydrobromic, sulfuric, cyclohexylsulfamic, phosphoric and nitric acids. It will be appreciated that in some instances, compounds of the present invention may include a carboxy group as a substituent. Such carboxy groups may be used to form salts, in particular pharmaceutically acceptable salts. Pharmaceutically acceptable salts include those described by Berge, Bighley, and Monkhouse, J. Pharm. Sci., 1977, 66, 1-19. Preferred salts include alkali metal salts such as the sodium and potassium salts.

When used herein, the term "alkyl" and similar terms such as "alkoxy" includes all straight chain and branched isomers. Representative examples thereof include methyl, ethyl, ra-propyl, wo-propyl, n-butyl, sec-butyl, iso-butyl, t-butyl, ra-pentyl and rc-hexyl.

When used herein, the term "aryl" refers to, unless otherwise defined, a mono- or bicyclic aromatic ring system containing up to 10 carbon atoms in the ring system, for instance phenyl or naphthyl.

When used herein, the term "heteroaryl" refers to a mono- or bicyclic heteroaromatic ring system comprising up to four, preferably 1 or 2, heteroatoms each selected from oxygen, nitrogen and sulphur. Each ring may have from 4 to 7, preferably 5 or 6, ring atoms. A bicyclic heteroaromatic ring system may include a carbocyclic ring.

When used herein, the terms "halogen" and "halo" include fluorine, chlorine, bromine and iodine and fluoro, chloro, bromo and iodo, respectively.

It will be understood that the present invention covers all combinations of substituent groups referred to hereinabove.

Compounds of the invention include:

N-(l-Ethylρiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(5-(4- trifluoromethylphenyl)pentyl)acetamide bitartrate; N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(3-(4- trifluoromethyl-phenyl)propyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(4-(4- trifluoromethylphenyl)butyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl) ethyl)-4-oxo-4H-quinolin-l-yl)-N- (5-(4-trifluoromethylphenyl)pentyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(6-(4- trifluoromethylphenyl)hexyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl)ethyl)-4-oxo-4H-quinolin-l-yl)-N-

(6-(4-trifluoromethylphenyl)hexyl)acetamide bitartrate; N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(7-(4- trifluoromethylphenyl)heptyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(8-(4- trifluoromethylphenyl)octyl)acetamide bitartrate; and N-(l-Ethylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl)ethyl)-4-oxo-4H-quinolin-l-yl)-N- (8-(4-trifluoromethylphenyl)octyl)acetamide bitartrate.

A preferred compound of formula (I) is N-(l-efhylpiperidin-4-yl)-2-(2-(2,3- difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(5-(4- trifluoromethylphenyl)pentyl)acetamide or the bitartrate salt thereof.

Since the compounds of the present invention, in particular compounds of formula (I), are intended for use in pharmaceutical compositions, it will be understood that they are each provided in substantially .pure form, for example at least 50% pure, more suitably at least 75% pure and preferably at least 95% pure (% are on a wt/wt basis). Impure preparations of the compounds of formula (I) may be used for preparing the more pure forms used in the pharmaceutical compositions. Although the purity of intermediate compounds of the present invention is less critical, it will be readily understood that the substantially pure form is preferred as for the compounds of formula (I). Preferably, whenever possible, the compounds of the present invention are obtained in crystalline form.

When some of the compounds of this invention are allowed to crystallise or are re- crystallised from organic solvents, solvent of crystallisation may be present in the crystalline product. This invention includes within its scope such solvates. Similarly, some of the compounds of this invention may be crystallised or re-crystallised from solvents containing water. In such cases water of hydration may be formed. This invention includes within its scope stoichiometric hydrates as well as compounds containing variable amounts of water that may be produced by processes such as lyophilisation. In addition, different crystallisation conditions may lead to the formation of different polymorphic forms of crystalline products. This invention includes within its scope all polymorphic forms of the compounds of formula (I).

Compounds of the present invention are inhibitors of the enzyme lipoprotein associated phospholipase A2 (Lp-PLA2) and as such are expected to be of use in therapy, in particular in the treatment of atherosclerosis. In a further aspect therefore the present invention provides a compound of formula (I) for use in therapy.

The compounds of formula (I) are inhibitors of lysophosphatidylcholine production by Lp-PLA2 and may therefore also have a general application in any disorder that involves endothelial dysfunction, for example atherosclerosis, diabetes, hypertension, angina pectoris and after ischaemia and reperfusion. In addition, compounds of formula (I) may have a general application in any disorder that involves lipid oxidation in conjunction with enzyme activity, for example in addition to conditions such as atherosclerosis and diabetes, other conditions such as rheumatoid arthritis, stroke, inflammatory conditions of the brain such as Alzheimer's Disease, myocardial infarction, ischaemia, reperfusion injury, sepsis, and acute and chronic inflammation. Further applications include any disorder that involves activated monocytes, macrophages or lymphocytes, as all of these cell types express Lp-PLA2- Examples of such disorders include psoriasis.

Accordingly, in a further aspect, the present invention provides for a method of treating a disease state associated with activity of the enzyme Lp-PLA2 which method involves treating a patient in need thereof with a therapeutically effective amount of an inhibitor of the enzyme. The disease state may be associated with the increased involvement of monocytes, macrophages or lymphocytes; with the formation of lysophosphatidylcholine and oxidised free fatty acids; with lipid oxidation in conjunction with Lp PLA2 activity; or with endothelial dysfunction.

Compounds of the present invention may also be of use in treating the above mentioned disease states in combination with an anti-hyperlipidaemic, anti-atherosclerotic, anti- diabetic, anti-anginal, anti-inflammatory, or anti-hypertension agent or an agent for lowering Lp(a). Examples of the above include cholesterol synthesis inhibitors such as statins, anti-oxidants such as probucol, insulin sensitisers, calcium channel antagonists, and anti-inflammatory drugs such as NSAIDs. Examples of agents for lowering Lp(a) include the aminophosphonates described in WO 97/02037, WO 98/28310, WO 98/28311 and WO 98/28312 (Symphar SA and SmithKline Beecham).

A preferred combination therapy will be the use of a compound of the present invention and a statin. The statins are a well known class of cholesterol lowering agents and include atorvastatin, simvarstatin, pravastatin, cerivastatin, fluvastatin, lovastatin and ZD 4522 (also referred to as S-4522, rosuvastatin, Astra Zeneca). The two agents may be administered at substantially the same time or at different times, according to the discretion of the physician.

A further preferred combination therapy will be the use of a compound of the present invention and an anti-diabetic agent or an insulin sensitiser, as coronary heart disease is a major cause of death for diabetics. Within this class, preferred compounds for use with a compound of the present invention include the PPARgamma activators, for instance GI262570 (GlaxoSmithKline) and the glitazone class of compounds such as rosiglitazone (Avandia, GlaxoSmithKline), troglitazone and pioglitazone.

In therapeutic use, the compounds of the present invention are usually administered in a standard pharmaceutical composition. The present invention therefore provides, in a further aspect, a pharmaceutical composition comprising a compound of formula (I) and a pharmaceutically acceptable carrier, optionally with one or more other therapeutic compounds such as a statin or anti-diabetic.

Suitable pharmaceutical compositions include those which are adapted for oral or parenteral administration or as a suppository, particularly for oral administration. Compounds of formula (I) which are active when given orally can be formulated as liquids, for example syrups, suspensions or emulsions, tablets, capsules and lozenges. A liquid formulation will generally consist of a suspension or solution of the compound or pharmaceutically acceptable salt in a suitable liquid carrier(s) for example, ethanol, glycerine, non-aqueous solvent, for example polyethylene glycol, oils, or water with a suspending agent, preservative, flavouring or colouring agent. A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations. Examples of such carriers include magnesium stearate, starch, lactose, sucrose and cellulose. A composition in the form of a capsule can be prepared using routine encapsulation procedures. For example, pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), for example aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule. Typical parenteral compositions consist of a solution or suspension of the compound of formula (I) in a sterile aqueous carrier or parenterally acceptable oil, for example polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration. A typical suppository formulation comprises a compound of formula (I) which is active when administered in this way, with a binding and/or lubricating agent such as polymeric glycols, gelatins or cocoa butter or other low melting vegetable or synthetic waxes or fats.

Preferably the composition is in unit dose form such as a tablet or capsule. Each dosage unit for oral administration contains preferably from 1 to 500 mg (and for parenteral administration contains preferably from 0.1 to 25 mg) of a compound of the formula (I). The daily dosage regimen for an adult patient may be, for example, an oral dose of between 1 mg and 1000 mg, preferably between 1 mg and 500 mg, or an intravenous, subcutaneous, or intramuscular dose of between 0.1 mg and 100 mg, preferably between 0.1 mg and 25 mg, of the compound of the formula (I), the compound being administered 1 to 4 times per day. Suitably the compounds will be administered for a period of continuous therapy, for example for a week or more.

According to a first process A, a compound of formula (I) may be prepared by reacting an acid compound of formula (H):

(π) in which X, Y, Rl, R^ and R^ are as hereinbefore defined, with an amine compound of formula (TH):

R⁶-R⁵-NHR⁴

(TH) in which R⁴, R5 and R^ are as hereinbefore defined; under amide forming conditions.

Suitable amide forming conditions are well known in the art and include treating the acid of formula (If) with the amine of formula (IH) in the presence of a coupling agent such as l-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide (DEC) or O-(7-azabenzotriazol-l-yl)- N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) in an aprotic solvent such as dichloromethane or dimethylformamide (DMF).

A compound of formula (H) may be readily prepared from a corresponding unsubstituted compound of formula (IN):

(IN) in which X, Y, Rl, R^ and R^ are as hereinbefore defined, by reaction with a compound of formula (V):

LCH2CO2R¹¹

(N) in which L js a leaving group such as trifluoromethanesulphonate or halo, for example chloro, bromo or iodo, and RU is Cπ _6)alkyl, for example t-butyl, in the presence of a base such as a tertiary amine, for example di-isopropylethylamine; to form an intermediate ester (NT),

(VI) in which X, Y, R^, R^, R3 and RU are as hereinbefore defined, and thereafter, removing RU, by treating with a de-esterifying agent, for instance, for t- butyl, trifluoroacetic acid. It will be appreciated that removal of R* * may be carried out as a separate step, so that an acid of formula (II), or a salt thereof, for example the sodium salt, is isolated or, alternatively, that the acid of formula (IT), or a salt thereof, is formed from the intermediate ester (NT), prior to reaction with an amine of formula (Ifl).

Thus according to a further process B a compound of formula (I) may be prepared by (a) treating a compound of formula (NT) with a de-esterifying agent to form a compound of formula (LI); and (b) treating said compound of formula (LI) with an amine compound of formula (HI) under amide forming conditions. In a further aspect, process B may comprise as a preliminary first step (a') reacting a compound of formula (IN) with a compound of formula (V) to form the ester (VI), which need not necessarily be isolated prior to treatment with a de-esterifying agent in step (a).

When Y is Ν, the pyrimidone of formula (TV) may be readily prepared by adapting a standard pyrimidone synthesis involving an amidine and a 1,3-dicarbonyl compound, by reacting an amidine of formula (NH):

ΝH

R ¹'X^^ Jl- ΝH

(VLT) in which R! and X are as hereinbefore defined, preferably as a salt thereof, for instance the hydrochloride salt, with a compound of formula (VHI):

(Nm) in which R^ and R^ are as hereinbefore defined.

It will be appreciated that in the compound of formula (IV), when R^ is hydrogen, the compound of formula (NHL) is a 1,3-aldehyde ester and further, that in the compound of formula (IV), when R^ is other than hydrogen, the compound of formula (VIII) is a 1,3- keto ester

For pyrimidone compounds of formula (H) in which R^ and R^ together with the pyrimidone ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring optionally substituted by halogen, C(i_6)alkyl, cyano, mono to perfluoro-C(i_4)alkyl, it is found more convenient to adopt a slightly different strategy whereby the amidine of formula (NIL) is reacted with a compound of the formula (TX):

(TX) in which R^ and R^ together with the pyrimidone ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring optionally substituted by halogen, C(i_ 6)alkyl, cyano, mono to perfluoro-Cπ_4)alkyl , and RU is as hereinbefore defined, for example ethyl, under standard pyrimidone ring forming conditions, in the presence of a base such as pyridine, to give an intermediate ester (NI) which can then be converted into a compound of formula (TI), for instance by treatment with aqueous sodium hydroxide.

Alternatively, for pyrimidone compounds of formula (II) in which R^ and R^ together with the pyrimidone ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring optionally substituted by halogen, Cπ _6)alkyl, cyano, mono to perfluoro- Cπ _4)alkyl, the pyrimidone ring may be formed by reacting a compound of formula (X):

(X) in which R^ and R^ together with the pyrimidone ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring optionally substituted by halogen, C(^_ 6)alkyl, cyano, mono to perfluoro-Cπ_4)alkyl, and RU is as hereinbefore defined, for example ethyl, with an acyl chloride compound of the formula (XI):

(XD in which * and X are as hereinbefore defined; under standard pyrimidone ring forming conditions, in a solvent such as benzene, or via a two step procedure by treatment with pyridine, followed by a suitable base e.g.

NaH in DMF, followed by treatment of the intermediate so formed with an acid e.g. p- toluene sulfonic acid in refluxing toluene; to give an intermediate ester (VI) which can then be converted into a compound of formula (II), for instance by treatment with aqueous sodium hydroxide.

When Y is CH, the overall synthesis of compounds of formula (I) is illustrated in the following scheme:

Referring to the scheme, the ester (VI) can be prepared by N-l alkylation of (LV) using (V) in which R! 1 as hereinbefore defined, e.g. (V) is t-butyl bromoacetate or ethyl bromoacetate, in the presence of a base e.g. BuLi in THF (step c).

When X is CH2S, the R*X substituent may be introduced by displacement of a leaving group i (e.g. Cl) (step e) either on a pyridine (XHT) or pyridine N-oxide (XLX), to give 2-substituted pyridines (XD) and (XX). Transformation of (XH) or (XX) to the 4- pyridone (IV) is accomplished by deprotection of the 4-oxygen (e.g. using (Ph3P)₃RhCl when in aq. ethanol when R*² = allyl) (step d), followed, for (XXI), by removal of the N- oxide substituent, using hydrogen in the presence of Pd/C in acetic acid (step k). The pyridine (XHI) or pyridine N-oxide (XLX) may be prepared by steps (i), (h), (g), (f), and (j), in which: (j) treatment of (XIII) with m-chloroperbenzoic acid in dichloromethane;

(f) treatment of (XIV) with R¹²OH (XV), in which R¹² is e.g. C(i_6)alkyl or allyl, and sodium hydride in DMF;

(g) treatment of (XVI) with phosphorus oxychloride; (h) treatment of (XVH) with aq HC1 with heating;

(i) treatment of (XVIH) with di-lower alkyl malonate and sodium alkoxide in alcohol (in which Rl3 is Cπ _6)alkyl, typically R 3 = Et); and R1- CH2SH (XXVTLL) is typically prepared from the thioacetate, which is formed from the corresponding alkyl bromide Rl-CH^Br.

Alternatively, when X is CH2S, the key intermediate (VI) may be synthesised by reacting (XXVI) with dimethyloxosulfonium methylide, generated via the treatment of trimethylsulfoxonium iodide with sodium hydride at low temperature, to yield a sulfur ylid (XXLX) (step (q). Subsequent treatment of (XXLX) with carbon disulfide in the presence of diisopropylethylamine, followed by RlCH^-L⁴, where ϊ is a leaving group, yields intermediate (VI) (step r).

Alternatively, when X is CH2S and R² and R^, together with the pyridone ring carbon atoms to which they are attached, form a fused benzo ring, intermediate (VI) may be synthesised from known starting materials by steps (s), (t) and (v) in which: (s) is treatment of Meldrum's acid (XXX) with sodium hydride at low temperature, followed by reaction with phenylisothiocyanate and subsequent treatment with RICH2- L⁴;

(t) N-l alkylation of (XXXH) using (V) in which RU is as hereinbefore defined, e.g. is t- butyl bromoacetate or ethyl bromoacetate, in the presence of a base e.g. sodium hydride in

N-methylpyrrolidone;

(v) treatment of (XXXI) with trifluoroacetic acid.

When X is (CH2)2_> it is preferable to use steps (m) and (1) (intermediates (XXIIL), (XXIV)) or steps (n) and (p) (intermediates (XXV), (XXVI), (XXVJL)) in which: (1) transformation of a 4-substituted pyridine into a 4-pyridone e.g. by treatment of (XXHl) R¹⁴ = Cl with aq HC1 and dioxan, or deprotection of R¹⁴ = OR¹², e.g. using conditions of step (d).

(m) chain extension of a 2-alkyl pyridine, e.g. where X = CH2CH2 by treatment of a 2- methylpyridine (XXLV) with RI-CH2-L⁴ (XXH) in which L⁴ is a leaving group and a strong base, such as BuLi, in THF.

In the alternative route, the 3-ester group is removed from intermediate (XXN) R¹^ = Cπ _6)alkyl by heating in diphenyl ether where R}$ = tBu (step n). intermediate (XXN) is formed from the 2,6-dioxo-l,3-oxazine (XXVI) and ester (XXVH) by treatment with a base (ΝaH) in DMF.

It will be appreciated that compounds of formula (I) may also be prepared from other compounds of formula (I) thereof using conventional interconversion procedures. Thus, a process for preparing a compound of formula (I) by interconversion of another compound of formula (I) (process C) constitutes a further aspect of the present invention.

It will be appreciated by those skilled in the art that it may be desirable to use protected derivatives of intermediates used in the preparation of compounds of formula (I). Thus, the above processes may require deprotection as an intermediate or final step to yield the desired compound. Thus, according to another process (D), a compound of formula (I) may be prepared by subjecting a protected derivative of a compound of formula (I) to reaction to remove the protecting group or groups present, constituting a further aspect of the present invention.

Protection and deprotection of functional groups may be effected using conventional means. Thus, hydroxyl groups may be protected using any conventional hydroxyl protecting group, for example, as described in Protective Groups in Organic Chemistry, Ed. J.F.W. McOmie (Plenum Press, 1973) or Protective Groups in Organic Synthesis by Theodora W. Green (John Wiley and Sons, 1991).

Examples of suitable hydroxyl protecting groups includes groups selected from alkyl (e.g. t-butyl or methoxymethyl), aralkyl (e.g. benzyl, diphenylmethyl or triphenylmethyl), heterocyclic groups such as tetrahydropyranyl, acyl (e.g. acetyl or benzoyl) and silyl groups such as trialkylsilyl (e.g. t-butyldimethylsilyl). The hydroxyl protecting groups may be removed by conventional techniques. Thus, for example alkyl, silyl, acyl and heterocyclic groups may be removed by solvolysis, e.g. by hydrolysis under acidic or basic conditions. Aralkyl groups such as triphenylmethyl may be similarly be removed by solvolysis, e.g. by hydrolysis under acidic conditions. Aralkyl groups such as benzyl may be cleaved by hydrogenolysis in the presence of a Noble metal catalyst such as palladium- on-charcoal.

The present invention will now be illustrated by the following examples.

Examples

The structure and purity of the intermediates and examples was confirmed by 1H-NMR and (in nearly all cases) mass spectroscopy, even where not explicitly indicated below.

Intermediate Al — (3-Cyanoprop-l-yl)triphenyIphosphonium bromide

Triphenylphosphine (8.86g, 33.7mmol) and 4-bromobutronitrile (3.4ml, 33.7mmol) were dissolved in toluene (60ml) and the solution was refluxed under argon for 18h. The resultant mixture was cooled and the solid collected by filtration, washed with ether, and dried under vacuum (5.89g, 53%). 1HNMR (CDC1₃) δ 2.11-1.96 (2H, m), 3.14-3.08 (2H, m), 4.23-4.11 (2H, m), 7.91-7.71 (15H, m).

Intermediate A2 — 5-(4-TrifluoromethyIphenyI)pent-4-enenitrile

Intermediate Al was added slowly to a round-bottomed flask containing sodium hydride (0.75g, 18.7mmol) in dry tetrahydrofuran (100ml) under argon at 0°C. The solution was stirred at room temperature for 15min after which time dimethyl sulphoxide (10ml) was added to help solubilise the phosphonium salt. After a further 2h, 4- (trifluoromethyl)benzaldehyde (3.4g, 19.59mmol) was added dropwise and the solution was stirred overnight. The reaction was quenched using saturated ammonium chloride and the residue extracted into ethyl acetate. The combined organic phases were washed with water, brine, dried (MgSO₄) and solvent evaporated. The crude product was purified by flash chromatography 5:1 petrol / ethyl acetate to give the title product (1.54g, 39%). 1H NMR (CDC1₃) δ 2.45 (2H, t), 2.65 (2H, q), 5.80-5.74 (1H, m), 6.65 (1H, d), 7.34 (2H, d), 7.61 (2H, d); MS (APCI) found (M+l) = 226; C₁₂H₁₀F₃N requires 225.

Intermediate A3 — 5-(4-TrifluoromethyIphenyl)pentylamine

Platinum oxide (10mol%) was added to a solution of intermediate A2 (1.54g, 6.83mmol) in ethanol (50ml). The system was purged with argon and then hydrogen several times to absorb hydrogen into the catalyst. 4.0M HC1 in dioxan (9ml) was added and the mixture stirred under hydrogen until the reaction was complete by HPLC. The platinum catalyst was filtered off and the solvent was evaporated to give the title compound (0.97g, 61%). 1H NMR (CDCI₃) δ 1.36-1.46 (2H, m) 1.55-1.75 (4H, m), 2.66 (2H, t), 3.84 (2H, t), 7.26 (2H, d), 7.52 (2H, d); MS (APCI) found (M+l) = 232; C₁₂H₁₆F₃N requires 231.

Intermediate A4 — N-(l-EthyIpiperidin-4-yl)-(5-(4- trifluoromethyIphenyl)pentyl)amine

Intermediate A3 (0.97g, 4.19mmol) and 1-ethyl piperidin-4-one (0.53g, 4.19mmol) in 1,2- dichloroethane (30ml) was treated with sodium triacetoxyborohydride (1.25g, 5.87mmol) and acetic acid (1ml) under argon and the mixture was stirred for 24h. The reaction was quenched by the addition of NaOH (2M, 8ml), extracted with ether, washed with brine, dried (K₂CO₃) and the solvent evaporated. The crude product was purified by chromatography, 5% 2.0M ammonia in methanol / dichloromethane to give the title compound (0.9g, 61%). 1H NMR (CDCI3) δ 1.0-3.6 (24H, m), 7.27 (2H, d),7.52 (2H, d); MS (APCI) found (M + 1) = 343; C₁₉H₂₉F₃N₂ requires 342.

Intermediate A5 — Methyl 4-(4-trifluoromethylphenyl)but-3-enoate

Methyl 3-butenoate (2.6g, 25.7mmol), 4-iodobenzotrifluoride (7g, 25.7mmol), tri-o-tolyl phosphine (0.78g, 2.57mmol), palladium acetate (0.12g, 0.51mmol) and triethylamine (7ml, 51.5mmol) were heated to 100°C in a Parr bomb for 18h. After cooling, the mixture was partitioned between dichloromethane and water. The aqueous layer was extracted with dichloromethane (2x) and the combined organic layers washed with brine, dried (MgSO₄) and evaporated. The crude product was purified by flash chromatography (light petrol / ethyl acetate) to give the title compound, (2.11g, 34%). 1HNMR (CDC1₃) δ 3.28 (2H, d), 3.72 (3H, s), 6.40 (IH, dt), 6.52 (IH, d), 7.45 (2H, d), 7.55 (2H, d); MS (APCI) found (M-l) = 243; C₁₂H_nF₃O₂ requires 244.

Intermediate A6 — Methyl 4-(4-trifluoromethylphenyl)butanoate

A mixture of intermediate A5 (3.26g, 13.3mmol) and Pd/C (10mol%) in methanol (50ml) was hydrogenated at room temperature and pressure until the reaction was complete by HPLC. The palladium catalyst was filtered off and the solvent evaporated to give the title compound (2.9g, 88%). 1H NMR (CDC1₃) δ 1.97 (2H, q), 2.34 (2H, t), 2.71 (2H, t), 3.67 (3H, s), 7.28 (2H, d), 7.53 (2H, d).

Intermediate A7 — 4-(4-trifluoromethylphenyl)butan-l-ol

Diisobutylaluminium hydride (16.2ml, 24.4mmol) was added dropwise to a solution of intermediate A6 (2.9g, 12.8mmol) in tetrahydrofuran (100ml) at -78°C and the reaction stirred for 2h. Saturated ammonium chloride (10ml) was added and the reaction allowed to warm to room temperature. The mixture was diluted with dichloromethane and excess celite added until a slurry formed. The mixture was filtered and the filtercake washed with dichloromethane. The combined organic layer was evaporated and the crude product purified by chromatography to give the title compound (1.37g, 51%). 1H NMR (CDC1₃) δ 1.5-1.75 (4H, m), 2.68 (2H, t), 3.64 (2H, t), 7.26 (2H, d), 7.52 (2H, d).

Intermediate A8 — 4- (4-trifluoromethylphenyl)butyraldehyde

Dimethyl sulphoxide (1.1ml, 15.1mmol) was added dropwise to a solution of oxalyl chloride (0.6ml, 6.91mmol) in dichloromethane (50ml) at -55°C and the solution stirred for 5min. Intermediate A7 (1.37g, 6.27mmol) in dichloromethane (10ml) was added dropwise. After 15min triethylamine (4.4ml, 31.4mmol) was added dropwise and stirring continued for a further 5min before warming to room temperature. Water (50ml) was added and the phases separated. The aqueous layer was extracted with dichloromethane and the combined organic layers dried (MgSO₄) and evaporated. The crude product was chromatographed to give the title compound (0.89g, 68%). 1H NMR (CDC1₃) δ 1.97 (2H, q), 2.47 (2H, d), 2.71 (2H, t), 7.28 (2H, d), 7.54 (2H, d), 9.78 (IH, s).

Intermediate A9 — N-(l-Ethylpiperidin-4-yl)-(4-(4- trifluoromethylphenyl)butyl)amine

A solution of intermediate A8 (0.89g, 4.1mmol) and 4-amino-l-ethylpiperidine (J.Am.Chem.Soc, 1946, 68, 1239) (0.53g, 4.1mmol) in tetrahydrofuran (50ml) over 4A molecular sieves was left to stand overnight. The sieves were filtered off and the solvent evaporated to give the crude imine. This imine was dissolved in ethanol (30ml) and then treated with sodium borohydride (0.26g, 6.7mmol). The reaction was stirred for 4h prior to the addition of water. The mixture was extracted with dichloromethane (3x). The combined organic layers were dried (MgSO₄) and then evaporated. The crude product was chromatographed to give the title compound (0.81g, 55%). 1H NMR (CDC1₃) δ 1.07 (3H, t), 1.3-2.0 (11H, m), 2.38 (3H, m), 2.66 (3H, m), 2.89 (2H, m), 7.27 (2H, d), 7.52 (2H, d); MS (APCI) found (M+l) = 329; C₁₈H₂₇F₃N₂ requires 328.

The following intermediates were made by the method of intermediate Al.

The following intermediates were prepared by the method of intermediate A2.

No. Precursor Structure

3-(4-Trifluoromethylphenyl)-

A21 Lnt. AH ^CN propenenitrile

6-(4-Trifluoromethylphenyl)-hex-

A22 Int. A12 5-enenitrile

7-(4-Trifluoromethylphenyl)-hept-

A23 Int. A13 6-enenitrile

8-(4-Trifluoromethylphenyl)-oct-

A24 Int. A14 7-enenitrile

The following intermediates were prepared by the method of intermediate A3.

The following intermediates were prepared by the method of intermediate A4.

Intermediate Bl - Dimethyloxosulphonium-2- (ethoxycarbonylmethylamino)benzoylmethylide

To a solution of trimethylsulphoxonium iodide (99g, 0.45mol) in DMSO (IL) at 5°C was added sodium hydride (19.4g, 0.485mol, 60% in oil) over 0.5h and the solution stirred for a further 0.5h until the reaction subsided. Ethyl 2-(2,4-dioxo-4H-benzo[d][l,3]oxazin-l- yl)acetate (HOg, 0.44mol) was then added to the solution over 0.33h and stirred for a further 3h after which time the reaction mixture was heated at 50°C for 1.5h. After cooling to ambient the solution was poured onto ice and the precipitate filtered off and washed with water then pentane. The solids were dried in vacuo at 40°C to provide the product (124.4g, 94%). -NMR (d6-DMSO) δ 1.2 (3H, t, J=7Hz), 3.5 (6H, s), 3.98 (2H, d, J=5.5Hz), 4.15 (2H, q, J=7Hz), 5.46 (lH,s), 6.44 (IH, d, J=8Hz), 6.52 (IH, t, J=7.4Hz), 7.17 (IH, t, J=7.4Hz), 7.47 (IH, d, J=8Hz), 8.93 (IH, br t, J=5.5Hz).

Intermediate B2 - 5-(l-(2,3-Difluorobenzylthio)-l-phenylamino-methylene)-2,2- dimethyl- [l,3]dioxane-4,6-dione

To hexane washed sodium hydride (7.45g, 60% in oil) under argon, was added N- methylpyrolidone (NMP) (270ml) and the mixture cooled in an ice-salt bath. 2,2- Dimethyl-l,3-dioxane-4,6-dione (26.8g) was added portionwise over 20min keeping the temperature between 5-10°C. Effervescence was noted during the addition. The mixture was stirred at room temperature for lh and phenylisothiocyanate (25.2g) added over 15min. The mixture was stirred at room temperature for 2.5h and cooled to 15°C in a cold water bath. 2,3-Difluorobenzyl bromide (38.6g) was added over lOmin and stirred at room temperature overnight. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate (1.2L) and water. The organic layer was washed with further water and then brine and dried over MgSO₄. The solvent was removed under reduced pressure and the residue triturated with 40-60°C petrol and the solid collected by filtration. Crystallisation from methyl t.butyl ether gave the title compound as a pale yellow solid (51.4g). ^-NMR (d₆-DMSO) δ 1.64 (6H, s), 4.16 (2H, d), 7.1-7.25 (2H, m), 7.25-7.5 (6H, m), 12.12 (IH, br s). MS (APCI-) found (M-l) = 404; C20H17F2NO4S requires 405.

Intermediate B3 - Ethyl 2-(l-(2,3-difluorobenzylthio)-l-(2,2-dimethyl-4,6-dioxo- [l,3]dioxan-5-ylidene)-methyl)phenylamino) acetate

To hexane washed sodium hydride (l.Og, 60% in oil) under argon, was added NMP (30ml). A solution of 5-(l-(2,3-Difluorobenzylthio)-l-phenylamino-methylene)-2,2- dimethyl-[l,3]dioxane-4,6-dione (lO.Og) (intermediate B2) in NMP (20ml) was added by syringe over 15min at room temperature and stirred for 30min. Ethyl bromoacetate (4.5g) was added and the mixture heated at 60°C for 6h. The mixture was partitioned between ethyl acetate and water and the aqueous layer extracted with further ethyl acetate. The combined organic layers were washed with further water and brine, dried over MgSO₄, and the solvent removed under reduced pressure. The orange oil so obtained was triturated with diethyl ether/ 40-60°C petrol to give a solid that was collected by filtration. This solid was recrystallised from methyl t.butyl ether to give the title compound (7.37g). iH-NMR (d₆-DMSO) δ 1.24 (3H, t), 1.55 (6H, br s), 4.19 (2H, q), 4.37 (2H, d), 4.81 (2H, br s), 6.85-7.5 (8H, 2xm). Intermediate B4 - Ethyl 2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl) acetate

A mixture of dimethyloxosulphonium-2-(ethoxycarbonylmethylamino)benzoylmethylide (0.30g, l.Olmmol) (intermediate Bl), carbon disulphide (0.13ml, 2.05mmol) and diisopropylethylamine (0.35ml, 2.02mmol) in DMF (4ml) was shaken under argon for 18h then 2,3-difluorobenzyl bromide (0.42g, 2.02mmol) added and the reaction shaken for a further 7h. The solution was concentrated and the residues separated between ethyl acetate and water. The organics were isolated, dried (MgSO ) and concentrated.

Purification by chromatography over silica eluting using a gradient from dichloromethane to dichloromethane/ ether 3:1 yielded the title compound (0.14g, 36%). 1H-NMR (dg- DMSO) δ 1.2 (3H, t, J=7Hz), 4.18 (2H, q, J=7Hz), 4.5 (2H, s), 5.3 (2H, s), 6.3 (IH, s), 7.18 (IH, m), 7.3 (IH, m), 7.4 (2H, m), 7.6 (IH, d, J=8.5Hz), 7.7 (IH, t, J=7Hz), 8.1 (IH, d, J=8Hz). MS (APCI+) found (M+l) = 390; C20H17F2NO3S requires 389.

Intermediate B4 was also prepared by the following procedure:

Ethyl 2-(l-(2,3-difluorobenzylthio)-l-(2,2-dimethyl-4,6-dioxo-[l,3]dioxan-5-ylidene)- methyl)phenylamino) acetate (intermediate B3) (0.85g) under argon was stirred with trifluoroacetic acid (10ml) at room temperature overnight. The mixture was evaporated under reduced pressure, dissolved in dichloromethane, washed with sodium bicarbonate solution and dried over Na₂SO₄. The solvent was removed under reduced pressure and the residue triturated with diethyl ether to give the title compound (0.43g). -Η-NMR (CDC1₃) δ 1.27 (3H, t), 4.26 (2H, q), 4.29 (2H, s), 5.1 (2H, br s), 6.45 (IH, s), 6.95-7.25 (4H, m), 7.39 (IH, t), 7.64 (IH, dt), 8.42 (IH, dd). Mass spectrum as above.

Intermediate B5 - 2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl) acetic acid

To a solution of ethyl 2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl) acetate (intermediate B4) (21.56g, 0.055mol) in dioxan (200ml) was added sodium hydroxide (6.0g, 0.15mol) in water (200ml) and the solution stirred for 2.5h then concentrated. The residues were dissolved in water and acidified to pΗ 2 with 2M hydrochloric acid and the precipitate collected and washed sequentially with water, ether and then hexane. The solids were dried in vacuo at 40°C to provide the title compound (20.0g, 100%). *H- NMR (d₆-DMSO) δ 4.5 (2H, s), 5.2 (2H, br s), 6.3 (IH, s), 7.18 (IH, m), 7.3 (IH, m), 7.4 (2H, m), 7.6 (IH, d, J=8.5Hz), 7.7 (IH, t, J=8Hz), 8.1 (IH, d, J=8Hz). MS (APCI+) found (M+l) = 362; Ci 8H13F2NO3S requires 361.

Intermediate B10 — 4-Chloro-2-(2-(2,3-difluorophenyl)ethyl)quinoline

Butyllithium (4.76 ml, 2.5M in hexanes, 1 equiv) was added dropwise to a solution of 4- chloroquinaldine (2.4 ml, 1 equiv) in tetrahydrofuran (30 ml) at -78°C and the reaction mixture stirred for 15 min. 2,3-Difluorobenzyl bromide (1.82 ml, 1.2 equiv) was added dropwise and stirring was continued for lh. After warming to room temperature the solution was diluted with water and ethyl acetate and the organic phase dried and evaporated. Chromatography (silica, 10:1 petrol / ethyl acetate) gave the title compound as a white solid (3.16 g). 1H-NMR (CDCI₃) δ 3.23 (4H, m), 6.89-6.99 (3H, m), 7.33 (IH, s), 7.59 (IH, m), 7.74 (IH, m), 8.04 (IH, d), 8.15 (IH, d); MS (APCI+) found (M+l) = 304; C₁₇H₁₂C1F₂N requires 303.

Intermediate Bll — 2-(2-(2,3-Difluorophenyl)ethyl)-l H-quinoline-4-one

4-Chloro-2-(2-(2,3-difluorophenyl)ethyl)quinoline ( B 10) (2.83 g) was heated to reflux in aqueous hydrochloric acid (2M, 15 ml) and dioxane (6 ml) for 72 h. The reaction mixture was diluted with dichloromethane (90 ml) and methanol (10 ml), and the organic phase dried and evaporated to give the title compound as a white solid (2.61 g). 1H-NMR (dβ-DMSO) δ 3.15 (4H, s), 6.46 (IH, s), 7.15 (2H, m), 7.27 (IH, m), 7.51 (IH, m), 7.82

(2H, m), 8.15 (IH, d); MS (APCI+) found (M+l) = 286; C₁₇H₁₃F₂NO requires 285.

Intermediate B12 — tert Butyl 2-(2-(2-(2,3-Difluorophenyl)ethyl)-4-oxo-4 H- quinolin-l-yl)-acetate

To a slurry of intermediate Bl 1 (lO.Og) in THF (250ml) under argon at 0°C was added n.butyl lithium (14.0ml, 2.5M in hexanes) dropwise. The mixture was allowed to warm to room temperature and stirred at that temperature for lh. t.Butyl bromoacetate (11.3ml) was added neat over 15min and the mixture heated at 40°C and stirred overnight. The mixture was carefully poured into saturated ammonium chloride solution, extracted with dichloromethane and the combined organic layers washed with brine and dried over MgSO₄. The solvent was removed under reduced pressure and the yellow solid so obtained was chromatographed on silica gel using CH₂C1₂ to 5%MeOH/CH₂Cl₂ as eluent to give the title compound (7.95g). ^-NMR (CDC1₃) δ 1.45 (9H, t), 2.85-3.0 (2H, m), 3.0-3.15 (2H, m), 4.82 (2H, br s), 6.27 (IH, s), 6.9-7.15 (3H, m), 7.29 (IH, d), 7.39 (IH, t), 7.65 (lH,t), 8.46 (IH, d). MS (APCI+) found (M+l) = 400; C23H23F2NO3 requires 399.

Intermediate B13 — 2-(2-(2-(2,3-Difluorophenyl)ethyl)-4-oxo-4 H-quinolin-1- yl)acetic acid

Trifluoroacetic acid (17ml) was added to a solution of tert Butyl 2-(2-(2-(2,3-difluoro- phenyl)ethyl)-4-oxo-4 H-quinolin-l-yl)-acetate (10.69g) (Intermediate B12) in dichloromethane (83ml) under argon, and stirred overnight at room temperature.

Evaporation of the solvent and trituration with ether gave the title compound as a white solid (8.26g). 1H-NMR (d₆-DMSO) δ 2.95-3.25 (4Η, m), 5.24 (2H, s), 6.20 (IH, s), 7.05- 7.25 (2H, m), 7.25-7.4 (IH, m), 7.45 (IH, t), 7.66 (IH, d), 7.79 (IH, m), 8.20 (IH, d). MS (APCI+) found (M+l) = 344; Ci 9H15F2NO3 requires 343.

Example 1 — N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H- quinolin-l-yl)-N-(5-(4-trifluoromethylphenyl)pentyl)acetamide bitartrate

0-(7-Azabenzotriazol-l-yl)-N,N,N',N-tetramethyluronium hexafluorophosphate (HATU) (0.154g, 0.5mmol) was added to a mixture of 2-(2-(2,3-difluorobenzylthio)-4-oxo-4H- quinolin-1-yl) acetic acid (intermediate B5) (0.15g, 0.42mmol), Ν-(l-Ethylpiperidin-4- yl)-(5-(4-trifluoromethylphenyl)pentyl)amine (intermediate A4) (0.142g, 0.42mmol) and diisopropylethylamine (0.17ml, 0.99mmol) in dimethylformamide (10ml) and the resultant suspension stirred for 2h. The mixture was diluted with dichloromethane (30ml) and washed successively with saturated ammonium chloride and saturated sodium bicarbonate. The organic layer was dried (K₂CO₃) and the solvent evaporated. The residue was purified by flash chromatography on silica gel (NΗ₃ / MeOH / CH₂C1 ). The amine (0.22g, 0.32mmol) was dissolved in methanol (10ml) and tartaric acid (0.05g, 0.32mmol) added. After stirring for 15min the solvent was evaporated and the residue triturated with diethyl ether to afford the title compound (0.22g). 1H NMR (d₆ DMSO) δ 1.0-2.1 (13H, m), 2.35-2.75 (5H, m), 3.1-3.6 (6H, m), 4.12 (2H, s), 4.47 (2H, s), 5.38 (2H, 2x br s), 6.31 (IH, 2x s), 7.48-7.13 (7H, m), 7.63 (3H, m), 8.13 (IH, d); MS (APCI) Found (M+l) = 686; C₃₇H₄oF₅N₃O₂S requires 685.

The following examples were prepared by the method of Example 1.

Biological Data

1. Screen for Lp-PLA2 inhibition.

Enzyme activity was determined by measuring the rate of turnover of the artificial substrate (A) at 37 °C in 50mM HEPES (N-2-hydroxyethylpiperazine-N -2- ethanesulphonic acid) buffer containing 150mM NaCl, pH 7.4.

(A)

Assays were performed in 96 well titre plates.

Recombinant L -PLA2 was purified to homogeneity from baculovirus infected Sf9 cells, using a zinc chelating column, blue sepharose affinity chromatography and an anion exchange column. Following purification and ultrafiltration, the enzyme was stored at 6mg/ml at 4 °C. Assay plates of compound or vehicle plus buffer were set up using automated robotics to a volume of 170μl.

The reaction was initiated by the addition of 20μl of lOx substrate (A) to give a final substrate concentration of 20μM and 10 μl of diluted enzyme to an approximate final O.lnMLp-PLAj.

The reaction was followed at 405 nm and 37 °C for 20 minutes using a plate reader with automatic mixing. The rate of reaction was measured as the rate of change of absorbance.

Results

The compounds described in the Examples were tested as described above and had IC50 values in the range <0.1 to 100 nM.

Claims

1. A compound of formula (I):

(I) in which:

R¹ is an aryl group, optionally substituted by 1, 2, 3 or 4 substituents which may be the same or different selected from C _6)alkyl, Cπ _6)alkoxy, Cπ _6)alkylthio, hydroxy, halogen, CN, mono to perfluoro-Cπ _4)alkyl, perfluoro-Cπ _4)alkoxy, and arylC(χ_4)alkyl;

R² is halogen, C(i_3)alkyl, C(χ_3)alkoxy, hydroxyC(χ_3)alkyl, C(χ_3)aιkylthio, Cπ_3)alkylsulphinyl, aminoCπ _3)alkyl, mono- or di-Cπ _3)alkylaminoCπ _3)alkyl, C(l-3)alkylcarbonylammoCπ_3)alkyl, C(i_3)alkoxyCπ_3)alkylcarbonylaminoCπ_ 3)alkyl, C(i_3)alkylsulphonylaminoC(i_3)alkyl, Cπ _3)a kylcarboxy, C(l-3)alkylcarboxyC(i_3)alkyl, and

R^ is hydrogen, halogen, Cπ_3)alkyl, or hydroxyCπ_3)alkyl; or R² and R^ together with the ring carbon atoms to which they are attached form a fused 5-or 6-membered carbocyclic ring; or R² and R^ together with the ring carbon atoms to which they are attached form a fused benzo or heteroaryl ring ring optionally substituted by 1, 2, 3 or 4 substituents which may be the same or different selected from halogen, Cπ _4)alkyl, cyano, C(χ_4)alkoxy or Cπ _4)aιkylfhio, or mono to perfluoro-C(χ_4)alkyl);

R⁴ is hydrogen, Cπ _5)alkyl which may be unsubstituted or substituted by 1, 2 or 3 substituents selected from hydroxy, halogen, OR^, COR^, carboxy, COOR^, CONR⁹R¹⁰, NR⁹R¹⁰, NR⁷COR⁸, mono- or di-(hydroxyC(i_6)alkyl)amino and N-hydroxyCπ .g^alkyl-N-Cπ _6)alkylamino; or

R⁴ is Het-C(Q-4)alkyl in which Het is a 5- to 7- membered heterocyclyl ring comprising N and optionally O or S, and in which N may be substituted by COR⁷, COOR⁷, CONR⁹Rl°, or C(χ_6)alkyl optionally substituted by 1, 2 or 3 substituents selected from hydroxy, halogen, OR⁷, COR⁷, carboxy, COOR⁷, CONR⁹R¹⁰ and NR Ri0, f_or instance, piperidin-4-yl, pyrrolidin-3-yl; R⁵ is (CH2)_p where p is 3 to 8;

R6 is an aryl or a heteroaryl ring which is further optionally substituted by 1, 2, 3 or 4 substituents which may be the same or different selected from Cπ __f5)aιkyl, C(j_

6)alkoxy, C(i_6)alkylthio, C^.g^alkylsulfonyl, arylC(i_6)alkoxy, hydroxy, halogen, CN, COR⁷, carboxy, COOR⁷, CONR⁹R1°, NR⁷COR⁸, SO₂NR⁹R¹⁰, NR⁷SO₂R⁸, NR⁹RlO, mono to perfluoro-C(2_4)alkyl and mono to perlTuoro-C(i_4)aιkoxy, or C(5_ιmalkyl;

R⁷ and R⁸ are independently hydrogen or Cπ _i2)alkyl, for instance Cπ _4)alkyl (e.g. methyl or ethyl); R⁹ and Rl^υ which may be the same or different is each selected from hydrogen, or C(i_χ2)alkyl, or R⁹ and RIO together with the nitrogen to which they are attached form a 5- to 7 membered ring optionally containing one or more further heteroatoms selected from oxygen, nitrogen and sulphur, and optionally substituted by one or two substituents selected from hydroxy, oxo, C(χ_4)alkyl, Cπ _4)alkylcarboxy, aryl, e.g. phenyl, or aralkyl, e.g benzyl, for instance morpholine or piperazine;

X is CH2S or (CH2)_n where n is 2 or 3; and

Y is CH orN; and pharmaceutically acceptable salts thereof.

2. A compound according to claim 1 wherein R¹ is phenyl optionally substituted by halogen, C_(1-6) alkyl, trifluoromethyl or C_(1-6) alkoxy.

3. A compound according to claim 1 or claim 2 wherein R² and R³ together with the ring carbon atoms to which they are attached form a fused 5- membered carbocyclic ring or a fused benzo, pyrido, thieno, or pyrazolo ring.

4. A compound according to any of claims 1 to 3, wherein R⁴ is hydrogen, methyl, 2- (diethylamino)ethyl, 2-(piperidin-l-yl)ethyl, 2-(pyrrolidin-l-yl)ethyl, 1-methyl- piperidinyl, l-ethyl-piperidin-4-yl, l-ethyl-pyrrolidin-2-ylmethyl or l-(2- methoxyethyl)piperidin-4-yl.

5. A compound according to any of claims 1 to 4 wherein R⁵ is (CH)₂p in which p is 3 to 8.

6. A compound according to any of claims 1 to 5 wherein R⁶ is phenyl optionally substituted by halogen or trifluoromethyl.

7. A compound according to any of claims 1 to 7 wherein X is (CH₂)₂ or CH₂S.

8. N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-

N-(5-(4-trifluoromethylphenyl)pentyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(3-(4- trifluoromethylphenyl)propyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl) ethyl)-4-oxo-4H-quinolin-l-yl)-N-

(5-(4-trifluoromethylphenyl)pentyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(6-(4- trifluoromethylphenyl)hexyl)acetamide bitartrate; N-(l-Efhylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl)ethyl)-4-oxo-4H-quinolin-l-yl)-N- (6-(4-trifluoromethylphenyl)hexyl)acetamide bitartrate;

N-(l-Ethylpiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(7-(4- trifluoromethylphenyl)heptyl)acetamide bitartrate; N-(l-Ethylρiperidin-4-yl)-2-(2-(2,3-difluorobenzylthio)-4-oxo-4H-quinolin-l-yl)-N-(8-(4- trifluoromethylphenyl)octyl)acetamide bitartrate; and

N-(l-Ethylpiperidin-4-yl)-2-(2-(2-(2,3-difluorophenyl)ethyl)-4-oxo-4H-quinolin-l-yl)-N- (8-(4-trifluoromethylphenyl)octyl)acetamide bitartrate;

9. A pharmaceutical composition comprising a compound of formula (I) as claimed in any of claims 1 to 8 and a pharmaceutically acceptable carrier.

10. A compound of formula (I) as claimed in any of claims 1 to 8 for use in therapy.

11. The use of a compound of formula (I) as claimed in any of claims 1 to 8 for the manufacture of a medicament for treating atherosclerosis.

12. A method of treating a disease state associated with activity of the enzyme Lp- PLA₂ which method involves treating a patient in need thereof with a therapeutically effective amount of a compound of formula (I) as claimed in any of claims 1 to 8.

13. A process for preparing a compound of formula (I) as defined in claim 1 which process comprises reacting an acid compound of formula (II):

(U) in which X, Y, Rl, R² and R^ are as hereinbefore defined, with an amine compound of formula (Tfl):

R⁶-R⁵-ΝHR⁴

(m) in which R⁴, R^ and R^ are as hereinbefore defined; under amide forming conditions.