Substituted imidazole derivatives and their use as cytokine inhibitors

Abstract: Novel 2,4,5-triarylimidazole compounds of formula: wherein R 1 is pyrimidinyl, optionally substituted with one or two substituents each of which is independently selected form C 1-4 alkyl, halo, C 1-4 alkoxy, C 1-4 alkylthio, NH 2 , mono- or di-C 1-6 -alkylamino and a N-heterocyclyl ring which ring has from 5 to 7 members, and optionally contains an additional heteroatom selected from oxygen, sulfur and NR 22 ; R 2 is R 8 or -OR 12 ; R 3 is -X a P(Z)(X b R 13 ) 2 or Q-(Y 1 ) t ; R 4 is phenyl, naphth-1-yl or naphth-2-yl; Q is an aryl or heteroaryl group; Y 1 is independently selected from hydrogen, C 1-5 alkyl, halo-substituted C 1-5 alkyl; R 8 is hydrogen, heterocyclyl, heterocyclylalkyl or R 11 ; R 11 is C 1-10 alkyl, halo-substituted C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl; processes for the preparation thereof, the use thereof in treating cytokine mediated diseases and pharmaceutical compositions for use in such therapy.

Description: This invention relates to a group of imidazole compounds, processes for the preparation thereof, the use thereof in treating cytokine mediated diseases and pharmaceutical compositions for use in such therapy. There has been much interest in the past few years in compounds which are cytokine-inhibitors, for use in treating disease states which are associated with the excessive or unregulated production of cytokines. Compounds of the general formula (A): Wherein R a is pyridyl, R b is optionally substituted phenyl and W is a partially or fully unsaturated fused 5- or 6-membered heterocyclic ring, such as pyrrolyl, pyridyl, dihydropyrrolyl, dihydropyridinyl, dihydrothiazolyl or tetrahydrotriazinyl, are inhibitors of the cytokines IL-1 and TNF (see WO88/01169, WO90/15534, WO91/00092, WO92/10190, WO92/10498 and WO92/12154, published after the filing of this application). In addition, these compounds are also inhibitors of the enzyme 5-lipoxygenase. We have now surprisingly found that if the ring W is replaced by certain substituents at the 2-position, cytokine-inhibitory activity is maintained. Such compounds are generically 2-substituted-4-aryl-5-heteroaryl-imidazoles. Compounds within this class have already been extensively investigated, as anti-inflammatory agents, acting principally as cyclo-oxygenase inhibitors, as described in, for instance, US patents 3,707,405 and 3,929,807. The latter discloses compounds of the general formula (B): Wherein one of R a and R b is optionally substituted phenyl and the other is a 6-membered heterocyclic ring with 1 or 2 nitrogen atoms and R c represents lower alkyl, cycloalkyl or phenyl optionally substituted by halogen, lower alkyl or lower alkoxy, in particular the compound 2-(4-chlorophenyl)-4-(4-methoxyphenyl)-5-(4-pyridyl)-imidazole. These compounds are said to have anti-inflammatory, analgesic and antipyretic activity. There is however no mention that these compounds may be cytokine inhibitors. Accordingly, the present invention provides a compound of formula (I): wherein: R 1 is pyrimidinyl, optionally substituted with one or two substituents each of which is independently selected from C 1-4 alkyl, halo, C 1-4 alkoxy, C 1-4 alkylthio, NH 2 , mono- or di-C 1-6 -alkylamino and a N-heterocyclyl ring which ring has from 5 to 7 members and optionally contains an additional heteroatom selected from oxygen, sulfur and NR 22 ; R 2 is selected from the group consisting of hydrogen, C 1-10 alkylor -OR 12 when R 12 is hydrogen;R 3 is Q-(Y 1 ) t ; Q is phenyl; t is an integer from 1 to 3; Z is oxygen or sulfur; n is 0 or an integer from 1 to 10; Y 1 is independently selected from hydrogen, C 1-5 alkyl, halo-substituted C 1-5 alkyl, halogenor -(CR 10 R 20 ) n Y 2 ; Y 2 is -OR 8 , -NO 2 , -S(O) m 'R 11 , -SR 8 , -S(O) m 'OR 8 , -S(O) m NR 8 R 9 , -NR 8 R 9 , -O(CR 10 R 20 ) n NR 8 R 9 , -C(O)R 8 , -CO 2 R 8 , -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , -ZC(O)R 8 , -CN, -C(Z)NR 8 R 9 , -NR 10 C(Z)R 8 , -C(Z)NR 8 OR 9 , -NR 10 C(Z)NR 8 R 9 , -NR 10 S(O) m R 11 , -N(OR 21 )C(Z)NR 8 R 9 , -N(OR 21 )C(Z)R 8 , -C(=NOR 21 )R 8 , -NR 10 C(=NR 15 )SR 11 , -NR 10 C(=NR 15 )NR 8 R 9 , -NR 10 C(=CR 14 R 24 )SR 11 , -NR 10 C(=CR 14 R 24 )NR 8 R 9 , -NR 10 C(O)C(O)NR 8 R 9 , -NR 10 C(O)C(O)OR 10 , -C(=NR 13 )NR 8 R 9 , -C(=NOR 13 )NR 8 R 9 , -C(=NR 13 )ZR 11 , -OC(Z)NR 8 R 9 , -NR 10 S(O) m CF 3 , -NR 10 C(Z)OR 10 , 5-(R 18 )-1,2,4-oxadiazol-3-yl or 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl; m' is 1 or 2; n' is an integer from 1 to 10; R 4 is phenyl, naphth-1-yl or naphth-2-yl which is optionally substituted by one or two substituents, each of which is independently selected, and which, for a 4-phenyl, 4naphth-1-yl or 5-naphth-2-yl substituent, is halo, cyano, -C(Z)NR 7 R 17 , -C(Z)OR 23 , -(CR 10 R 20 ) m COR 36 , -SR 5 , -SOR 5 , -OR 36 , halo-substituted-C 1-4 alkyl, C 1-4 alkyl, -ZC(Z)R 36 , -NR 10 C(Z)R 23 , or -(CR 10 R 20 ) m NR 10 R 20 ; and which, for other positions of substitution, is halo, cyano, -C(Z)NR 16 R 26 , -C(Z)OR 8 , -(CR 10 R 20 ) m COR 8 , -S(O) m R 8 , -OR 8 , halo-substituted-C 1-4 alkyl, -C 1-4 alkyl, -(CR 10 R 20 ) m NR 10 C(Z)R 8 , -NR 10 S(O) m R 11 , -NR 10 S(O) m NR 7 R 17 wherein m is 1 or 2, -ZC(Z)R 8 or -(CR 10 R 20 ) m NR 16 R 26 ; m is 0, or the integer 1 or 2; R 5 is hydrogen, C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl or NR 7 R 17 , excluding the moieties -SR 5 being -SNR 7 R 17 and -SOR 5 being -SOH; R 6 is C 1-4 alkyl, halo-substituted-C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl or C 3-5 cycloalkyl; R 7 and R 17 is each independently selected from hydrogen and C 1-4 alkyl, or R 7 and R 17 together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 22 ; R 8 is hydrogen, heterocyclyl, heterocyclylalkyl or R 11 ; R 9 is hydrogen, C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, or R 8 and R 9 may together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 12 ; R 10 and R 20 is each independently selected from hydrogen and C 1-4 alkyl; R 11 is C 1-10 alkyl, halo-substituted C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl; R 12 is hydrogen, -C(Z)R 13 or optionally substituted C 1-4 alkyl, optionally substituted aryl or optionally substituted aryl-C 1-4 alkyl; R 13 is hydrogen, C 1-10 alkyl, cycloalkyl, heterocyclyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl; R 14 and R 24 is each independently selected from hydrogen, alkyl, nitro and cyano; R 15 is hydrogen, cyano, C 1-4 alkyl, C 3-7 cycloalkyl or aryl; R 16 and R 26 is each independently selected from hydrogen or optionally substituted C 1-4 alkyl, optionally substituted aryl or optionally substituted aryl-C 1-4 alkyl, or together with the nitrogen which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 12 ; R 18 and R 19 is each independently selected from hydrogen, C 1-4 alkyl, substituted alkyl, optionally substituted aryl, and optionally substituted arylalkyl; or together denote an oxygen or sulfur; R 21 is hydrogen, a pharmaceutically acceptable cation, C 1-10 alkyl, C 3-7 cycloalkyl, aryl, aryl C 1-4 alkyl, heteroaryl, heteroarylalkyl, heterocyclyl, aroyl, or C 1-10 alkoyl ; R 22 is R 10 or C(Z)-C 1-4 alkyl; R 23 is C 1-4 alkyl, halo-substituted-C 1-4 alkyl, or C 3-5 cycloalkyl; R 36 is hydrogen or R 23 ; as used herein halo refers to all halogens, that is chloro, fluoro, bromo and iodo; C 1-10 alkyl or alkyl refers to both straight and branched chain radicals of 1 to 10 carbon atoms, unless the chain length is otherwise limited, including methyl, ethyl, n -propyl, iso -propyl, n -butyl, sec -butyl, iso -butyl or tert -butyl; aryl refers to phenyl and naphthyl; heteroaryl refers to (on its own or in any combination, such as heteroaryloxy) a 5-10 membered aromatic ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O and S, such as, to pyrrole, quinoline, isoquinoline, pyridine, pyrimidine, oxazole, thiazole, thiadiazole, triazole, imidazole, and benzimidazole; heterocyclic (on its own or in any combination, such as heterocyclylalkyl) refers to a saturated or wholly or partially unsaturated 4-10 membered ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O, or S; such as, pyrrolidine, piperidine, piperazine, morpholine, imidazolidine and pyrazolidine; aroyl refers to a C(O)Ar, wherein Ar is as phenyl, naphthyl, or aryl alkyl derivatives, such as benzyl; alkoyl refers to a C(O)C 1-10 alkyl wherein the alkyl is as defined above; sulfinyl refers to the oxide (SO) of the corresponding sulfide whilst the term "thio" refers to the sulfide; or a pharmaceutically acceptable salt thereof. Preferably R 1 is substituted with C 1-4 alkyl or NR 10 R 20 . Preferably, R 2 is hydrogen or methyl. Preferably t is 1 or 2. More preferably, when R 3 is monosubstituted phenyl, the substituent is located at the 4-position. Suitably Q is substituted by up to three substituents Y 1 each of which is independently selected from C 1-5 alkyl, halo-substituted C 1-5 alkyl, halogen, -X a -P(Z)-(X b R 13 ) 2 or -(CR 10 R 20 ) n Y 2 wherein Y 2 is -OR 8 , -NO 2 , -S(O) m' R 11 , -SR 8 , -S(O) m' OR 8 , -S(O) m NR 8 R 9 , -NR8R9, -O(CR 10 R 20 ) n NR 8 R 9 , -C(O)R 8 , -CO 2 R 8 , -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , -ZC(O)R 8 , -CN, -C(Z)NR 8 R 9 , -NR 10 C(Z)R 8 , -C(Z)NR 8 OR 9 , -NR 10 C(Z)NR 8 R 9 , -NR 10 S(O) m R 11 , N(OR 21 )C(Z)NR 8 R 9 , -N(OR 21 )C(Z)R 8 , -C(=NOR 21 )R 8 , -NR 10 C(=NR 15 )SR 11 , NR 10 C(=NR 15 )NR 8 R 9 , -NR 10 C(=CR 14 R 24 )SR 11 , -NR 10 C(=CR 14 R 24 )NR 8 R 9 , -NR 10 C(O)C(O)NR 8 R 9 , -NR 10 C(O)C(O)OR 10 , -C(=NR 13 )NR 8 R 9 , -C(=NOR 13 )NR 8 R 9 , -C(=NR 13 )ZR 11 , -OC(Z)NR 8 R 9 , -NR 10 S(O) m CF 3 , -NR 10 C(Z)OR 10 , 5-(R 18 )-1,2,4-oxadiazol-3-yl and 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl; m' is 1 or 2; R 9 is hydrogen, C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl or R 8 and R 9 may together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 12 ; R 14 and R 24 is each independently selected from hydrogen, alkyl, nitro and cyano; R 15 is hydrogen, cyano, C 1-4 alkyl, C 3-7 cycloalkyl or aryl; R 18 and R 19 is each independently selected from hydrogen, C 1-4 alkyl, substituted alkyl, optionally substituted aryl, arylalkyl or together with the carbon to which they are attached denote a double bonded oxygen or sulfur, i.e., a C=O or C=S; and R 21 is hydrogen, a pharmaceutically acceptable cation, alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl, heterocyclic, heteroarylalkyl, aroyl or alkoyl. Preferred substituents Y 1 for use in R 3 include halogen, C 1-5 alkyl and -(CR 10 R 20 ) n Y 2 wherein Y 2 is -OR 8 , -NO 2 , -S(O) m' R 11 , -SR 8 , -S(O) m NR 8 R 9 ; NR 8 R 9 , -O(CR 10 R 20 ) n NR 8 R 9 , -C(O)R 8 , -CO 2 R 8 , -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , -CN; -C(Z)NR 8 R 9 , -NR 10 S(O) m R 11 , -NR 10 C(Z)R 8 , -NR 10 C(Z)NR 8 R 9 , -C(Z)NR 8 OR 9 , -N(OR 21 )C(Z)NR 8 R 9 , -NR 10 C(=NR 15 )NR 8 R 9 , -C(=NOR 13 )NR 8 R 9 , 5-(R 18 )-1,2,4-oxadiazol-3-yl or 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl. Preferred substituents Y 1 for use in R 3 when Q is mono-substituted include -(CR 10 R 20 ) n Y 2 wherein: n is 0, 1, 2 or 3, preferably 0 or 1; and Y 2 is -OR 8 , especially where R 8 is hydrogen or C 1-10 alkyl; -NO 2 ; -S(O) m' R 11 , especially where R 11 is C 1-10 alkyl; -SR 8 , especially where R 8 is C 1-10 alkyl; -S(O) m NR 8 R 9 , especially where R 8 and R 9 is each hydrogen or C 1-10 alkyl or R 8 and R 9 together with the nitrogen to which they are attached form a 5 to 7 membered ring which optionally includes another heteroatom selected from oxygen, sulfur or NR 12 and m is 2; n' is 1 to 10; -NR 8 R 9 , especially where R 8 and R 9 is each hydrogen, methyl or benzyl or R 8 and R 9 together with the nitrogen to which they are attached form a 5 to 7 membered ring which optionally includes another heteroatom selected from oxygen, sulfur and NR 12 ; -O(CR 10 R 20 ) n R 8 R 9 , especially where R 8 and R 9 is each C 1-10 alkyl; -C(O)R 8 , especially where R 8 is hydrogen or C 1-10 alkyl; -CO 2 R 8 , especially where R 8 is hydrogen or C 1-10 alkyl; -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , especially where R 8 and R 9 is hydrogen or C 1-10 alkyl; -CN; -C(Z)NR 8 R 9 , especially where R 8 and R 9 is hydrogen or C 1-10 alkyl; -NR 10 S(O) m R 11 , especially where R 10 is hydrogen or C 1-10 alkyl and R 11 is C 1-10 alkyl or a halosubstituted ; -NR 10 C(Z)R 8 , especially where R 8 is C 1-10 alkyl and R 10 is hydrogen and Z is oxygen; -C(Z)NR 8 OR 9 , especially where R 8 and R 9 is each hydrogen and Z is oxygen; -NR 10 C(Z)NR 8 R 9 , especially where R 8 and R 9 is each hydrogen or C 1-10 alkyl and Z is oxygen; N(OR 21 )C(Z)NR 8 R 9 , especially where R 8 especially where R 8 , R 9 and R 21 is each hydrogen or C 1-10 alkyl and Z is oxygen; -C(=NOR 13 )NR 8 R 9 , especially where R 8 , R 9 and R 13 is each hydrogen; -NR 10 C(=NR 15 )NR 8 R 9 , especially where R 8 and R 9 is hydrogen, C 1-10 alkyl or arylalkyl and R 15 is cyano; and 5-(R 18 )-1,2,4-oxadiazol-3-yl and 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl, especially where R 12 is hydrogen and R 18 and R 19 is each hydrogen or C 1-10 alkyl or together are oxo. Preferred substituents for use in R 3 when Q is disubstituted include those hereinbefore listed for use when Q is mono-substituted and, as further substituent(s), halogen and C 1-10 alkyl. When R 3 is substituted with two or three substituents, the alkyl moieties preferably have from one to three carbons, more preferably one. Preferred ring positions for two substituents are the 3- and 4-positions and, for three substituents, the 3-, 4- and 5- positions. The substituent at the 3- and 5-positions is preferably C 1-2 alkyl, such as methyl, or halogen, such as bromo, fluoro or chloro, while the substituent at the 4-position is preferably hydroxyl. More preferably, for R 3 substituents wherein Y 1 is (CR 10 R 20 ) n Y 2 , n is 0 or 1 and Y 2 is -OH, -S(O) m' R 11 , especially where R 11 is C 1-10 alkyl; -SR 8 , especially where R 8 is C 1-10 alkyl; -NR 8 R 9 , especially where R 8 and R 9 is hydrogen, alkyl, aryl alkyl, or aryl, or R 8 and R 9 together with the nitrogen to which they are attached form a pyrrolidinyl, piperidinyl or morpholinyl ring, more preferably the R 8 and R 9 terms in the NR 8 R 9 moiety are hydrogen, methyl or benzyl; -CO 2 R 8 , especially where R 8 is hydrogen or C 1-10 alkyl; -S(O) m' NR 8 R 9 , especially where R 8 and R 9 is each hydrogen or C 1-10 alkyl; -NR 10 S(O) m R 11 , especially where R 10 is hydrogen and R 11 is C 1-10 alkyl or 5-(R 18 )-1,2,4-oxadiazol-3-yl and 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl, especially where R 12 is hydrogen and R 18 and R 19 is hydrogen or C 1-10 alkyl or together are oxo. Most preferably, Y 1 is methylthio, ethylthio, methylsulfinyl, ethylsulfinyl, methylsulfonyl, N,N-dimethylaminomethyl, N-benzyl-N-methylaminomethyl, N-morpholinomethyl, methanesulfonamido, sulphonamidomethyl, 5-methyl-4,5-dihydro-1,2,4-oxadiazol-3-yl or 5,5-dimethyl-4,5-dihydro-1,2,4-oxadiazol-3-yl. In all instances herein where there is an alkenyl or alkynyl moiety as a substituent group, such as in R 5 , R 8 , R 9 , or R 11 the unsaturated linkage, i.e., the vinylene or acetylene linkage is preferably not directly attached to the nitrogen, oxygen or sulfur moieties, for instance in Y 2 as C(Z)NR 8 OR 9 , NR 10 C(Z)NR 8 R 9 , or OR 8 . As used herein, "optionally substituted" unless specified refers to such groups as halogen, hydroxyl, alkoxy, S(O)m alkyl, amino, mono & di-substituted amino, such as a NR 7 R 17 group, alkyl or cycloalkyl, i.e. such as in optionally substituted aryl or optionally substituted arylalkyl. When R 3 includes a X a -P(Z)(X b R 13 ) 2 group linked either directly to the imidazole ring or indirectly via an aryl or heteroaryl group, X a is suitably oxygen or C 1-4 alkylene, optionally interrupted by oxygen, for instance -CH 2 OCH 2 - and Z and X b is each oxygen, such that the preferred groups include -OP(O)(OR 13 ) 2 and -CH 2 OCH 2 -P(O)(OR 13 ) 2 . Preferred substitutions for R 4 when this is a 4-phenyl, 4-naphth-1-yl or 5-naphth-2-yl moiety are one or two substituents each independently selected from halogen, -SR 5 , -SOR 5 , -OR 36 , or -(CR 10 R 20 ) m NR 10 R 20 , and for other positions of substitution on these rings preferred substitution is halogen, -S(O) m R 8 , - OR 8 , -(CR 10 R 20 ) m NR 16 R 26 , -NR 10 C(Z)R 8 and -NR 10 S(O) m R 11 . More preferred substituents for the 4-position in phenyl and naphth-1-yl and on the 5-position in naphth-2-yl include halogen, especially fluoro and chloro, and -SR 5 and - SOR 5 wherein R 5 is preferably a C 1-2 alkyl, more preferably methyl; of which fluoro is especially preferred. Preferred substituents for the 3-position in phenyl and naphth-1-yl include: halogen, especially chloro; -OR 8 , especially C 1-4 alkoxy; amino; -NR 10 C(Z)R 8 , especially -NHCO(C 1-10 alkyl); and -NR 10 S(O) m R 11 , especially -NHSO 2 (C 1-10 alkyl). Preferably, the R 4 moiety is an unsubstituted or substituted phenyl moiety. More preferably, R 4 is phenyl or phenyl substituted at the 4-position with fluoro and/or substituted at the 3-position with fluoro, chloro, C 1-4 alkoxy, methanesulfonamido or acetamido. Suitable pharmaceutically acceptable salts are well known to those skilled in the art and include basic salts of inorganic and organic acids, such as hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, methane sulfonic acid, ethane sulfonic acid, acetic acid, malic acid, tartaric acid, citric acid, lactic acid, oxalic acid. succinic acid, fumaric acid, maleic acid, benzoic acid, salicylic acid, phenylacetic acid and mandelic acid. In addition, pharmaceutically acceptable salts of compounds of formula (I) may also be formed with a pharmaceutically acceptable cation, for instance, if a substituent Y 1 in R 3 comprises a carboxy group. Suitable pharmaceutically acceptable cations are well known to those skilled in the art and include alkaline, alkaline earth, ammonium and quaternary ammonium cations. The following terms, as used herein, refer to: "halo" - all halogens, that is chloro, fluoro, bromo and iodo; "C 1-10 alkyl" or "alkyl" - both straight and branched chain radicals of 1 to 10 carbon atoms, unless the chain length is otherwise limited, including, methyl, ethyl, n -propyl, iso -propyl, n -butyl, sec -butyl, iso -butyl, or tert -butyl ; "aryl" - phenyl and naphthyl; "heteroaryl" (on its own or in any combination, such as "heteroaryloxy") - a 5-10 membered aromatic ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O and S, such as, to pyrrole, quinoline, isoquinoline, pyridine, pyrimidine, oxazole, thiazole, thiadiazole, triazole, imidazole, and benzimidazole; "heterocyclic" (on its own or in any combination, such as "heterocyclylalkyl") - a saturated or wholly or partially unsaturated 4-10 membered ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O, or S; such as, pyrrolidine, piperidine, piperazine, morpholine, imidazolidine and pyrazolidine; "aroyl" - a C(O)Ar, wherein Ar is as phenyl, naphthyl, or aryl alkyl derivatives, such as benzyl ; "alkoyl" - a C(O)C 1-10 alkyl wherein the alkyl is as defined above; "sulfinyl" - the oxide (SO) of the corresponding sulfide whilst the term "thio" refers to the sulfide. The compounds of the present invention may contain one or more asymmetric carbon atoms and may exist in racemic and optically active forms. All of these compounds are included within the scope of the present invention. For the purposes herein of nomenclature, the compounds of formula (I) are named by their position corresponding to: Especially preferred compounds of formula (I) include: 4-(4-Fluorophenyl)-N-1-hydroxy-5-(4-pyrimidinyl)-imidazole; 4-(4-Fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyrimidinyl)-1H-imidazole; 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyrimidinyl)-1H-imidazole; 4-(4-Fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyrimidinyl)-1H-imidazole; and pharmaceutically acceptable salts thereof. Compounds of formula (I) are imidazole derivatives which may be readily prepared using procedures well-known to those skilled in the art, and described in, for instance, Comprehensive Heterocyclic Chemistry, ed Katritzky and Rees, Pergamon Press, 1984, 5 , 457-497, from starting materials which are either commercially available or can be prepared from such by analogy with well-known processes. A key step in many such syntheses is the formation of the central imidazole nucleus, to give compounds of formula (I). Suitable procedures are described in inter alia US patent nos. 3,707,475 and 3,940,486 which are herein incorporated by reference in their entirety. These patents describe the synthesis of α-diketones and α-hydroxyketones (benzoins) and their subsequent use in preparing imidazoles and N-hydroxyl imidazoles. Thereafter, further compounds of formula (I) may be obtained by manipulating substituents in any of the groups R 1 , R 2 , R 3 and R 4 using conventional functional group interconversion procedures. In particular, in a first process, compounds of formula (I) may be prepared by condensing an α-diketone of formula (II): R 1 COCOR 4 wherein R 1 and R 4 are as hereinbefore defined, or an equivalent thereof, with an aldehyde of the formula (III): R 3 CHO wherein R 3 is as hereinbefore defined, or an equivalent thereof, and, if necessary, with ammonia or a source thereof, under imidazole-ring forming conditions. Suitable equivalents of the α-diketone are well known to those skilled in the art and include the corresponding α-keto-oxime and α-dioxime. Suitable equivalents of the aldehyde of formula (III) are well known in the art and include the corresponding oxime and acetal. Ammonia, or a source thereof, is preferably used in excess, with at least a dimolar amount being used in the case of the α-diketone and at least an equimolar amount in the case of the α-keto-oxime. Suitable sources of ammonia include ammonium salts of organic carboxylic acids, such as an ammonium C 1-6 alkanoate, for instance ammonium acetate and ammonium formate, preferably ammonium acetate, and carboxylic amides, in particular of formic acid, such as formamide. An ammonium salt is generally used in large excess and in the presence of an acid, such as a C 1-6 carboxylic acid which acid may also be used as a solvent for the reaction. If formamide is used, this may be used in excess, as the reaction solvent. An alternative solvent such as ethanol or dimethyl sulphoxide (Lantos et al , J Het Chem, 19 , 1375, 1982) may be used. An additional solvent may also be employed, for instance, dimethyl formamide may be used with formamide. The reaction is generally carried out at elevated temperatures, for instance under reflux conditions, and if desired, in a sealed vessel optionally under pressure and/or an inert gas atmosphere, for instance nitrogen. A further suitable source of ammonia is hydroxylamine, in which case the initially formed imidazole is an N-hydroxy-N-oxide imidazole. This may then be reduced to the corresponding N-hydroxy imidazole by treating with a suitable reducing agent such as sodium borohydride, in an appropriate solvent such as methanol, following the method of Akange and Allan, Chem and Ind, 5 Jan 1975, 38. The N-hydroxy imidazole may in turn be converted to an imidazole of formula (I) in which R 2 is hydrogen by treatment with a conventional deoxygenating agent such as phosphorus trichloride or a trialkylphosphite such as trimethyl- or triethyl-phosphite. N-hydroxy-N-oxide imidazoles may be readily obtained by treating an α-diketone of formula (II) with an aldehyde of formula (II) with about two equivalents of hydroxylamine or the corresponding aldoxime and about one equivalent of hydroxylamine, under proton catalysis. Alternatively, the N-oxide may be obtained by the acid catalysed condensation of the corresponding α-dioxime or α-keto-oxime with an aldoxime of the aldehyde of formula (III). When the compound of formula (II) is an α-keto-oxime derivative, it will be appreciated that the product initially obtained will be a compound of formula (I) in which R 2 is hydroxyl which may be converted into a compound of formula (I) in which R 2 is hydrogen as described above. It will be appreciated by those skilled in the art that in some instances, it will not be necessary to provide a separate source of ammonia as the α-diketone or aldehyde equivalent may already contain such a source. Examples of this include α-dioxime or α-keto-oxime and aldoxime. The compounds of formula (II) may be obtained by applying well-known synthetic procedures, some of which are illustrated in schemes I and II. Although these illustrate syntheses in which R 1 is either 4-pyridyl or 4-quinolinyl, they may be equally applied to R 1 is pyrimidinyl by appropriate choice of starting material. In Scheme I, the anion prepared from 1 , by treatment with a strong base such as lithium di- iso -propylamide, is condensed with a substituted benzaldehyde, to give, after removal of the protecting group, the diol 2 . This may then be converted to the α-diketone 3 by a Swern oxidation of which any number of potentially useful variations are known and may be used. The α-diketone 3 is then cyclized to an imidazole 4 , a compound of formula (I), by heating 3 with a substituted benzaldehyde in a mixture of ammonium acetate, as the source of ammonia, and an appropriate solvent, for example acetic acid or DMSO. The imidazole 4 may then be transformed into other imidazoles 5 by appropriate functional group interconversion procedures. Scheme I also illustrates the preparation of a protected α-hydroxyketone 2a , by condensing the anion of 1 with an appropriately activated carbonyl derivative of a substituted benzamide, such as the N-methoxy-N-methylamide, to yield a protected α-hydroxyketone. This adduct 2a may then be directly converted to the imidazole 5 , using a combination of a copper (II) salt, such as copper (II) acetate, as an oxidising agent and ammonium acetate as a source of ammonia. The α-hydroxyketone 2a may also be deprotected and then oxidised to give an α-diketone 3 , for instance using Swern oxidation. Scheme II illustrates the use of an α-keto-oxime for preparing a compound of formula (I). A heterocyclic ketone 7 is prepared by adding the anion of 4-methylquinoline (prepared by treatment thereof with an alkyl lithium, such as n -butyl lithium) to an N-alkyl-O-alkoxybenzamide. Alternatively, the anion may be condensed with a benzaldehyde, to give an alcohol which is then oxidised to the ketone 7 . The α-ketooxime 8 is then prepared from 7 using standard conditions, such as reaction with sodium nitrite, and this may then be reacted with a benzaldehyde to afford an N-hydroxyimidazole 9 , a compound of formula (I) in which R 2 is hydroxy. This may converted to 10 , a further compound of formula (I) in which R 2 is hydrogen, by treating it with a deoxygenating agent such as phosphorus trichloride or a trialkyl phosphite, such as trimethyl or triethylphosphite. For compounds of formula (I) wherein R 3 is -(CR 10 R 20 ) n -P(Z)-(X b R 13 ) 2 , the reagent OHC-(CR 10 R 20 ) n -P(Z)-(X b R 13 ) 2 may be used instead of OHC-C 6 H 4 -X to make the appropriately substituted compound 9 . In a further process, a compound of formula (I) may be obtained by treating an α-hydroxyketone compound of formula (IIA): R'CHOHCOR" wherein one of R' and R" is R 1 and the other is R 4 , a suitably protected derivative thereof or the α-hydroxy-oxime or α-haloketone derivative thereof, with an oxidising agent capable of converting said compound into the corresponding α-diketone, in the presence of an aldehyde of formula (III) or an equivalent thereof, and a source of ammonia. Suitable oxidising agents include, for example, an oxidising heavy metal salt, preferably an organic copper (II) salt, such as copper (II) acetate or copper (II) citrate. The reaction may be effected in a solvent such as acetic acid, under reflux conditions. Alternatively, a lower alkanol solvent, such as methanol or ethanol, may be used, preferably at a temperature in the region of from 30 to 100°C (see The Chemistry of Heterocyclic Compounds, Imidazole and its derivatives, part I, ed. Weissberger, Interscience Publishers, Inc., New York, 1953, 38). This approach is also illustrated in Scheme I. In a further process, a compound of formula (I) may be obtained by treating an amidine of formula (IV): R 3 C(=NH)NHR 2 wherein R 2 and R 3 are as hereinbefore defined, or a salt thereof, with a reactive ester of an α-hydroxyketone of formula (IIA) or the corresponding α-haloketone, in an inert solvent such as a halogenated hydrocarbon solvent, for example chloroform, at a moderately elevated temperature and, if necessary, in the presence of a suitable condensation agent such as a base. Suitable reactive esters include esters of strong organic acids such as a lower alkane sulfonic or aryl sulfonic acid, for instance, methane or p -toluene sulfonic acid. The amidine of formula (IV) is preferably used as the salt, suitably the hydrochloride salt, which may then be converted into the free amidine in situ , by employing a two phase system in which the reactive ester is in an inert organic solvent such as chloroform, and the salt is in an aqueous phase to which a solution of an aqueous base is slowly added, in dimolar amount, with vigorous stirring. Suitable amidines of formula (IV) may be obtained by standard methods, see for instance, Garigipati R, Tetrahedron Letters, 190, 31 , 1989. In a further process, a compound of formula (I) may be obtained by treating an iminoether of formula (V): R 3 C=NOR wherein R 3 is as hereinbefore defined and R is C 1-10 alkyl, aryl or aryl C 1-4 alkyl, with an α-aminoketone of the formula (VI): R'CHNH 2 COR" wherein one of R' and R" is R 1 and the other is R 4 in a suitable solvent. In a further process, N-substituted compounds of formula (I) may be prepared by treating the anion of an amide of formula (VII): R 1 CH 2 NR 2 COR 3 wherein R 1 and R 3 are as hereinbefore defined and R 2 is as hereinbefore defined other than hydrogen, with: (a) a nitrile of the formula (VIII): R 4 CN wherein R 4 is as hereinbefore defined, or (b) an excess of an acyl halide, for instance an acyl chloride, of the formula (IX): R 4 COHal wherein R 4 is as hereinbefore defined and Hal is halogen, or a corresponding anhydride, to give a bis -acylated intermediate which is then treated with a source of ammonia, such as ammonium acetate. This approach permits the regiospecific preparation of compound of formula (I) substituted at the 1-position, as illustrated in Scheme III. A primary amine RNH 2 is treated with 4-chloromethylpyridine to give 11 which is then converted to the amide 12 by standard techniques. Deprotonation of 12 with a strong amide base, such as lithium di- iso -propyl amide or sodium bis -(trimethylsilyl)amide, followed by addition of an excess of an aroyl chloride yields the bis -acylated compound 13 which is then closed to an imidazole compound of formula (I), 14 , by heating in acetic acid containing ammonium acetate. Alternatively, the anion of 12 may be reacted with a substituted aryl nitrile to produce the imidazole 14 directly. In a further process, compounds of formula (I) may be prepared by treating a compound of formula (X): R'COCHR"X c COR 3 wherein R', R" and R 3 are as hereinbefore defined and X c is O or NH, with a source of ammonia, as hereinbefore described, under imidazole ring forming conditions or cyclising the corresponding Schiff's base, formed by treating the compound of formula (X) in which X c is NH with an amine R 2 NH 2 , for instance thermally or with the aid of a cyclising agent such as phosphorus oxychloride or phosphorus pentachloride (see Engel and Steglich, Liebigs Ann Chem, 1978, 1916 and Strzybny et al ., J Org Chem, 1963, 28 , 3381). Compounds of formula (X) may be obtained, for instance, by acylating the corresponding α-keto-oxime (X c is NH) or α-hydroxyketone (X c is O) with an acyl halide of the formula R 3 COHal wherein R 3 is as hereinbefore defined, or the corresponding anhydride, under standard acylating conditions. In a further process, compounds of formula (I) may be prepared by coupling a suitable derivative of a compound of formula (XI): wherein: T 2 is a nitrogen protecting group or R 2 , other than hydrogen; and T 1 is hydrogen, T 3 is Q and T 4 is R 4 ; T 1 is R 1 , T 3 is hydrogen and T 4 is R 4 ; or T 1 is R 1 , T 3 is Q and T 4 is hydrogen , in which R 1 , R 2 , R 3 , R 4 and Q are as hereinbefore defined; with: (i) when T 1 is hydrogen, a suitable derivative of the heteroaryl ring R 1 H, under ring coupling conditions, to effect coupling of the heteroaryl ring R 1 to the imidazole nucleus at position 5; (ii) when T 3 is hydrogen, a suitable derivative of the aryl or heteroaryl ring QH, under ring coupling conditions, to effect coupling of the ring Q to the imidazole nucleus at position 2; or (iii) when T 4 is hydrogen, a suitable derivative of the aryl ring R 4 H, under ring coupling conditions, to effect coupling of the aryl ring R 4 to the imidazole nucleus at position 4. Such aryl/heteroaryl coupling reactions are well known to those skilled in the art. In general, an organometallic synthetic equivalent of an anion of one component is coupled with a reactive derivative of the second component, in the presence of a suitable catalyst. The anion equivalent may be formed from either the imidazole of formula (XI), in which case the aryl/heteroaryl compound provides the reactive derivative, or the aryl/heteroaryl compound in which case the imidazole provides the reactive derivative. Accordingly, suitable derivatives of the compound of formula (XI) or the aryl/heteroaryl rings include organometallic derivatives such as organomagnesium, organozinc, organostannane and boronic acid derivatives and suitable reactive derivatives include the bromo, iodo, fluorosulfonate and trifluoromethanesulphonate derivatives. Suitable procedures are described in WO91/19497, the disclosure of which is herewith incorporated. Suitable organomagnesium and organozinc derivatives of a compound of formula (XI) may be reacted with a halogen, fluorosulfonate or triflate derivative of the heteroaryl or aryl ring, in the presence of a ring coupling catalyst, such as a palladium (O) or palladium (II) catalyst, following the procedure of Kumada et al ., Tetrahedron Letters, 22 , 5319 (1981). Suitable such catalysts include tetrakis -(triphenylphosphine)palladium and PdCl 2 [1,4- bis -(diphenylphosphino)-butane], optionally in the presence of lithium chloride and a base, such as triethylamine. In addition, a nickel (II) catalyst, such as Ni(II)Cl 2 (1,2-biphenylphosphino)ethane, may also be used for coupling an aryl ring, following the procedure of Pridgen, Org Chem, 1982, 47 , 4319. Suitable reaction solvents include hexamethylphosphoramide. When the heteroaryl ring is 4-pyridyl, suitable derivatives include 4-bromo- and 4-iodopyridine and the fluorosulfonate and triflate esters of 4-hydroxy-pyridine. Similarly, suitable derivatives for when the aryl ring is phenyl include the bromo, fluorosulfonate, triflate and, preferably, the iodo-derivatives. Suitable organomagnesium and organozinc derivatives may be obtained by treating a compound of formula (XI) or the bromo derivative thereof with an alkyllithium compound to yield the corresponding lithium reagent by deprotonation or transmetallation, respectively. This lithium intermediate may then be treated with an excess of a magnesium halide or zinc halide to yield the corresponding organometallic reagent. A trialkyltin derivative of the compound of formula (XI) may be treated with a bromide, fluorosulfonate, triflate, or, preferably, iodide derivative of an aryl or heteroaryl ring compound, in an inert solvent such as tetrahydrofuran, preferably containing 10% hexamethylphosphoramide, in the presence of a suitable coupling catalyst, such as a palladium (0) catalyst, for instance tetrakis -(triphenylphosphine)palladium, by the method described in by Stille, J Amer Chem Soc, 1987, 109 , 5478; US Patents 4,719,218 and 5,002,942; or by using a palladium (II) catalyst in the presence of lithium chloride optionally with an added base such as triethylamine, in an inert solvent such as dimethyl formamide. Trialkyltin derivatives may be conveniently obtained by metallation of the corresponding compound of formula (XI) with a lithiating agent, such as s -butyl-lithium or n -butyllithium, in an ethereal solvent, such as tetrahydrofuran, or treatment of the bromo derivative of the corresponding compound of formula (XI) with an alkyl lithium, followed, in each case, by treatment with a trialkyltin halide. Alternatively, the bromo-derivative of a compound of formula (XI) may be treated with a suitable heteroaryl or aryl trialkyl tin compound in the presence of a catalyst such as tetrakis -(triphenylphosphine)-palladium, under conditions similar to those described above. Boronic acid derivatives are also useful. Hence, a suitable derivative of a compound of formula (XI), such as the bromo, iodo, triflate or fluorosulphonate derivative, may be reacted with a heteroaryl- or aryl-boronic acid, in the presence of a palladium catalyst such as tetrakis -(triphenylphosphine)-palladium or PdCl 2 [1,4- bis -(diphenylphosphino)-butane] in the presence of a base such as sodium bicarbonate, under reflux conditions, in a solvent such as dimethoxyethane (see Fischer and Haviniga, Rec. Trav. Chim. Pays Bas. 84 , 439, 1965, Snieckus, V., Tetrahedron Lett., 29 , 2135, 1988 and Terashimia, M., Chem. Pharm. Bull., 11 , 4755, 1985). Nonaqueous conditions, for instance, a solvent such as DMF, at a temperature of about 100°C, in the presence of a Pd(II) catalyst may also be employed (see Thompson W J et al , J Org Chem, 49 , 5237, 1984). Suitable boronic acid derivatives may be prepared by treating the magnesium or lithium derivative with a trialkylborate ester, such as triethyl, tri- iso -propyl or tributylborate, according to standard procedures. In such coupling reactions, it will be readily appreciated that due regard must be exercised with respect to functional groups present in the compounds of formula (XI). Thus, in general, amino and sulfur substituents should be non-oxidised or protected and the N-1 nitrogen of a compound of formula (XI) be protected, if an NH compound is finally required. Nitro, bromo, iodo and hydroxyl groups should preferably be avoided in compounds of formula (XI) in which T 1 is hydrogen. Compounds of formula (XI) are imidazoles and may be obtained by any of the procedures herein before described for preparing compounds of formula (I). In particular, an α-halo-ketone R 4 COCH 2 Hal (for compounds of formula (XI) in which T 1 is hydrogen) or R 1 COCH 2 Hal (for compounds of formula (XI) in which T 4 is hydrogen) may be reacted with an amidine of formula (IV) or a salt thereof, in an inert solvent such as a halogenated hydrocarbon solvent, for instance chloroform, at a moderately elevated temperature, and, if necessary, in the presence of a suitable condensation agent such as a base. The preparation of suitable α-halo-ketones is described in WO91/19497. For a compound of formula (XI) in which T 3 is hydrogen, an α-diketone of formula (II) may be condensed with formaldehyde or an equivalent thereof, in the presence of a source of ammonia. Suitable bromo derivatives of the compound of formula (XI) may be obtained by brominating the corresponding compound of formula (XI) under standard brominating conditions, for instance bromine in a solvent such as dichloromethane or THF. Compounds of formula (I) may also be prepared by a process which comprises reacting a compound of formula (XI), wherein T 1 is hydrogen, with an N-acyl heteroaryl salt, according to the method disclosed in US patents 4,803,279, 4,719,218 and 5,002,942, to give an intermediate in which the heteroaryl ring is attached to the imidazole nucleus and is present as a 1,4-dihydro derivative thereof, which intermediate may then be subjected to oxidative-deacylation conditions. The heteroaryl salt, for instance a pyridinium salt, may be either preformed or, more preferably, prepared in situ by adding a substituted carbonyl halide (such as an acyl halide, an aroyl halide, an arylalkyl haloformate ester, or, preferably, an alkyl haloformate ester, such as acetyl bromide, benzoyl chloride, benzyl chloroformate, or, preferably, ethyl chloroformate) to a solution of the compound of formula (XI) in the heteroaryl compound R 1 H or in an inert solvent such as methylene chloride to which the heteroaryl compound has been added. Suitable deacylating and oxidising conditions are described in U.S. Patent Nos. 4,803,279, 4,719,218 and 5,002,942, which references are hereby incorporated in their entirety. Suitable oxidising systems include sulfur in an inert solvent or solvent mixture, such as decalin, decalin and diglyme, p -cymene, xylene or mesitylene, under reflux conditions, or, preferably, potassium t -butoxide in t -butanol with dry air or oxygen. Once the imidazole nucleus has been established, further compounds of formula (I) which may be prepared by applying standard techniques for functional group interconversion, for instance: -C(O)NR 8 R 9 from -CO 2 CH 3 by heating with or without catalytic metal cyanide, e.g. NaCN, and HNR 8 R 9 in CH 3 OH; -OC(O)R 8 from -OH with e.g., ClC(O)R 8 in pyridine; -NR 10 -C(S)NR 8 R 9 from -NHR 10 with an alkylisothiocyante or thiocyanic acid; NR 6 C(O)OR 6 from -NHR 6 with the alkyl chloroformate; -NR 10 C(O)NR 8 R 9 from -NHR 10 by treatment with an isocyanate, e.g. HN=C=O or R 10 N=C=O; -NR 10 -C(O)R 8 from -NHR 10 by treatment with ClC(O)R 8 in pyridine; -C(=NR 10 )NR 8 R 9 from -C(NR 8 R 9 )SR 8 with H 3 NR 8 + OAc - by heating in alcohol; -C(NR 8 R 9 )SR 8 from -C(S)NR 8 R 9 with R 6 -I in an inert solvent, e.g. acetone; -C(S)NR 8 R 9 (where R 8 or R 9 is not hydrogen) from -C(S)NH 2 with HNR 8 R 9 , -C(=NCN)-NR 8 R 9 from -C(=NR 8 R 9 )-SR 8 with NH 2 CN by heating in anhydrous alcohol, alternatively from -C(=NH)-NR 8 R 9 by treatment with BrCN and NaOEt in EtOH; -NR 10 -C(=NCN)SR 8 from -NHR 10 by treatment with (R 8 S) 2 C=NCN; -NR 10 SO 2 R 8 from -NHR 10 by treatment with ClSO 2 R 8 by heating in pyridine; -NR 10 C(S)R 8 from -NR 10 C(O)R 8 by treatment with Lawesson's reagent [2,4- bis (4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide]; -NR 10 SO 2 CF 3 from -NHR 6 with triflic anhydride and base; -NR 10 C(O)-C(O)-OR 8 from -NHR 10 with, e.g. methyloxalyl chloride and a base such as triethylamine; -NR 10 C(O)-C(O)-NR 8 R 9 from -NR 10 C(O)-C(O)-OR 8 with HNR 8 R 9 ; and 1-(NR 10 )-2-imidazolyl from -C(=NH)NHR 10 by heating with 2-chloroacetaldehyde in chloroform (wherein R 6 , R 8 , R 9 and R 10 are as hereinbefore defined). Compounds of formula (I) in which R 2 is hydrogen may be readily converted into further compounds of formula (I) in which R 2 is other than hydrogen, for instance alkyl, by conventional procedures such as alkylation or acylation followed by reduction. Such methods are in general relatively inefficient as they lack regiospecificity and the desired N-1 product has to be separated from the mixture of N-1 and N-3 products, for instance by chromatography or fractional crystallisation. Suitable protecting groups for use with hydroxyl groups and the imidazole nitrogen are well known in the art and described in many references, for instance, Protecting Groups in Organic Synthesis, Greene T W, Wiley-Interscience, New York, 1981. Suitable examples of hydroxyl protecting groups include silyl ethers, such as t-butyldimethyl or t-butyldiphenyl, and alkyl ethers, such as methyl connected by an alkyl chain of variable link, (CR 10 R 20 ) n . Suitable examples of imidazole nitrogen protecting groups include tetrahydropyranyl. Pharmaceutically acid addition salts of compounds of formula (I) may be obtained in known manner, for example by treatment thereof with an appropriate amount of acid in the presence of a suitable solvent. The compounds of Formula (I) or a pharmaceutically acceptable salt thereof can be used in the manufacture of a medicament for the prophylactic or therapeutic treatment of any disease state in a human, or other mammal, which is exacerbated or caused by excessive or unregulated cytokine production by such mammal's cell, such as but not limited to monocytes and/or macrophages. Compounds of formula (I) are capable of inhibiting proinflammatory cytokines, such as IL-1, IL-6, IL-8 and TNF and are therefore of use in therapy. IL-1, IL-8 and TNF affect a wide variety of cells and tissues and these cytokines, as well as other leukocyte-derived cytokines, are important and critical inflammatory mediators of a wide variety of disease states and conditions. The inhibition of these pro-inflammatory cytokines is of benefit in controlling, reducing and alleviating many of these disease states. Accordingly, the present invention provides compounds of formula (I) as or a pharmaceutically acceptable salt thereof, for use in therapy. In another aspect the invention provides the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for treating a cytokine-mediated disease state. In a further aspect, the invention provides pharmaceutical compositions comprising an effective, non-toxic amount of a of formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent. The present specification describes a method of treating a cytokine-mediated disease which comprises administering an effective cytokine-interfering amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. In particular, compounds of formula (I) or a pharmaceutically acceptable salt thereof are of use in the prophylaxis or therapy of any disease state in a human, or other mammal, which is exacerbated by or caused by excessive or unregulated IL-1, IL-8 or TNF production by such mammal's cell, such as, but not limited to, monocytes and/or macrophages. Accordingly, this specification describes a method of inhibiting the production of IL-1 in a mammal in need thereof which comprises administering to said mammal an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. There are many disease states in which excessive or unregulated IL-1 production is implicated in exacerbating and/or causing the disease. These include rheumatoid arthritis, osteoarthritis, endotoxemia and/or toxic shock syndrome, other acute or chronic inflammatory disease states such as the inflammatory reaction induced by endotoxin or inflammatory bowel disease, tuberculosis, atherosclerosis, muscle degeneration, multiple sclerosis, cachexia, bone resorption, psoriatic arthritis, Reiter's syndrome, rheumatoid arthritis, gout, traumatic arthritis, rubella arthritis and acute synovitis. Recent evidence also links IL-1 activity to diabetes, pancreatic β cells and Alzheimer's disease. In a further aspect, this specifiaction describes a method of inhibiting the production of TNF in a mammal in need thereof which comprises administering to said mammal an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof Excessive or unregulated TNF production has been implicated in mediating or exacerbating a number of diseases including rheumatoid arthritis, rheumatoid spondylitis, osteoarthritis, gouty arthritis and other arthritic conditions, sepsis, septic shock, endotoxic shock, gram negative sepsis, toxic shock syndrome, adult respiratory distress syndrome, cerebral malaria, chronic pulmonary inflammatory disease, silicosis, pulmonary sarcoisosis, bone resorption diseases, such as osteoporosis, reperfusion injury, graft vs. host reaction, allograft rejections, fever and myalgias due to infection, such as influenza, cachexia secondary to infection or malignancy, cachexia secondary to acquired immune deficiency syndrome (AIDS), AIDS, ARC (AIDS related complex), keloid formation, scar tissue formation, Crohn's disease, ulcerative colitis and pyresis. Compounds of formula (I) are also useful in the treatment of viral infections, where such viruses are sensitive to upregulation by TNF or will elicit TNF production in vivo . The viruses contemplated for treatment herein are those that produce TNF as a result of infection, or those which are sensitive to inhibition, such as by decreased replication, directly or indirectly, by the TNF inhibiting-compounds of formula (1). Such viruses include, but are not limited to HIV-1, HIV-2 and HIV-3, Cytomegalovirus (CMV), Influenza, adenovirus and the Herpes group of viruses, such as but not limited to, Herpes Zoster and Herpes Simplex. Accordingly, in a further aspect, this invention relates to a method of treating a mammal afflicted with a human immunodeficiency virus (HIV) which comprises administering to such mammal an effective TNF inhibiting amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. Compounds of formula (I) may also be used in association with the veterinary treatment of mammals, other than in humans, in need of inhibition of TNF production. TNF mediated diseases for treatment, therapeutically or prophylactically, in animals include disease states such as those noted above, but in particular viral infections. Examples of such viruses include, but are not limited to, the lentivirus infections such as equine infectious anaemia virus, caprine arthritis virus, visna virus, or the maedi virus, or the retroviruses, such as feline immunodeficiency virus (FIV), bovine immunodeficiency virus, or canine immunodeficiency virus. The compounds of formula (I) may also be used topically in the treatment or prophylaxis of topical disease states mediated by or exacerbated by excessive cytokine production, such as by IL-1 or TNF respectively, such as inflamed joints, eczema, psoriasis and other inflammatory skin conditions such as sunburn; inflammatory eye conditions including conjunctivitis; pyresis, pain and other conditions associated with inflammation. Compounds of formula (I) have also been shown to inhibit the production of IL-8 (Interleukin-8, NAP). Accordingly, in a further aspect, this invention relates to a method of inhibiting the production of IL-8 in a mammal in need thereof which comprises administering to said mammal an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. There are many disease states in which excessive or unregulated IL-8 production is implicated in exacerbating and/or causing the disease. These diseases are characterised by massive neutrophil infiltration such as, psoriasis, inflammatory bowel disease, asthma, cardiac and renal reperfusion injury, adult respiratory distress syndrome, thrombosis and glomerulonephritis. All of these diseases are associated with increased IL-8 production which is responsible for the chemotaxis of neutrophils into the inflammatory site. In contrast to other inflammatory cytokines (IL-1, TNF, and IL-6), IL-8 has the unique property of promoting neutrophil chemotaxis and activation. Therefore, the inhibition of IL-8 production would lead to a direct reduction in the neutophil infiltration. The compounds of formula (I) are administered in an amount sufficient to inhibit cytokine, in particular IL-1, IL-8 or TNF, production such that it is regulated down to normal levels, or in some case to subnormal levels, so as to ameliorate or prevent the disease state. Abnormal levels of IL-1, IL-8 or TNF, for instance in the context of the present invention, constitute: (i) levels of free (not cell bound) IL-1, IL-8 or TNF greater than or equal to 1 picogram per ml; (ii) any cell associated IL-1, IL-8 or TNF; or (iii) the presence of IL-1, IL-8 or TNF mRNA above basal levels in cells or tissues in which IL-1, IL-8 or TNF, respectively, is produced. The discovery that the compounds of formula (I) are inhibitors of cytokines, specifically IL-1, IL-8 and TNF is based upon the effects of the compounds of formulas (I) on the production of the IL-1, IL-8 and TNF in in vitro assays which are described herein. As used herein, the term "inhibiting the production of IL-1 (IL-8 or TNF)" refers to: a) a decrease of excessive in vivo levels of the cytokine (IL-1, IL-8 or TNF) in a human to normal or sub-normal levels by inhibition of the in vivo release of the cytokine by all cells, including but not limited to monocytes or macrophages; b) a down regulation, at the genomic level, of excessive in vivo levels of the cytokine (IL-1, IL-8 or TNF) in a human to normal or sub-normal levels; c) a down regulation, by inhibition of the direct synthesis of the cytokine (IL-1, IL-8 or TNF) as a postranslational event; or d) a down regulation, at the translational level, of excessive in vivo levels of the cytokine (IL-1, IL-8 or TNF) in a human to normal or sub-normal levels. As used herein, the term "TNF mediated disease or disease state" refers to any and all disease states in which TNF plays a role, either by production of TNF itself, or by TNF causing another monokine to be released, such as but not limited to IL-1, IL-6 or IL-8. A disease state in which, for instance, IL-1 is a major component, and whose production or action, is exacerbated or secreted in response to TNF, would therefore be considered a disease stated mediated by TNF. As used herein, the term "cytokine" refers to any secreted polypeptide that affects the functions of cells and is a molecule which modulates interactions between cells in the immune, inflammatory or hematopoietic response. A cytokine includes, but is not limited to, monokines and lymphokines, regardless of which cells produce them. For instance, a monokine is generally referred to as being produced and secreted by a mononuclear cell, such as a macrophage and/or monocyte. Many other cells however also produce monokines, such as natural killer cells, fibroblasts, basophils, neutrophils, endothelial cells, brain astrocytes, bone marrow stromal cells, epideral keratinocytes and B-lymphocytes. Lymphokines are generally referred to as being produced by lymphoctye cells. Examples of cytokines include, but are not limited to, Interleukin-1 (IL-1), Interleukin-6 (IL-6), Interleukin-8 (IL-8), Tumor Necrosis Factor-alpha (TNF-α) and Tumor Necrosis Factor beta (TNF-B). As used herein, the term "cytokine interfering" or "cytokine suppressive amount" refers to an effective amount of a compound of formula (I) which will cause a decrease in the in vivo levels of the cytokine to normal or sub-normal levels, when given to a patient for the prophylaxis or treatment of a disease state which is exacerbated by, or caused by, excessive or unregulated cytokine production. As used herein, the cytokine referred to in the phrase "inhibition of a cytokine, for use in the treatment of a HIV-infected human" is a cytokine which is implicated in (a) the initiation and/or maintenance of T cell activation and/or activated T cell-mediated HIV gene expression and/or replication and/or (b) any cytokine-mediated disease associated problem such as cachexia or muscle degeneration. As TNF-β (also known as lymphotoxin) has close structural homology with TNF-α (also known as cachectin) and since each induces similar biologic responses and binds to the same cellular receptor, both TNF-α and TNF-β are inhibited by the compounds of the present invention and thus are herein referred to collectively as "TNF" unless specifically delineated otherwise. In order to use a compound of formula (I) or a pharmaceutically acceptable salt thereof in therapy, it will normally be formulated into a pharmaceutical composition in accordance with standard pharmaceutical practice. This invention, therefore, also relates to a pharmaceutical composition comprising an effective, non-toxic amount of a compound of formula (I) and a pharmaceutically acceptable carrier or diluent. Compounds of formula (I), pharmaceutically acceptable salts thereof and pharmaceutical compositions incorporating such may conveniently be administered by any of the routes conventionally used for drug administration, for instance, orally, topically, parenterally or by inhalation. The compounds of formula (I) may be administered in conventional dosage forms prepared by combining a compound of formula (I) with standard pharmaceutical carriers according to conventional procedures. The compounds of formula (I) may also be administered in conventional dosages in combination with a known, second therapeutically active compound. These procedures may involve mixing, granulating and compressing or dissolving the ingredients as appropriate to the desired preparation. It will be appreciated that the form and character of the pharmaceutically acceptable character or diluent is dictated by the amount of active ingredient with which it is to be combined, the route of administration and other well-known variables. The carrier(s) must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. The pharmaceutical carrier employed may be, for example, either a solid or liquid. Exemplary of solid carriers are lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid and the like. Exemplary of liquid carriers are syrup, peanut oil, olive oil, water and the like. Similarly, the carrier or diluent may include time delay material well known to the art, such as glyceryl monostearate or glyceryl distearate alone or with a wax. A wide variety of pharmaceutical forms can be employed. Thus, if a solid carrier is used, the preparation can be tableted, placed in a hard gelatin capsule in powder or pellet form or in the form of a troche or lozenge. The amount of solid carrier will vary widely but preferably will be from about 25mg. to about 1g. When a liquid carrier is used, the preparation will be in the form of a syrup, emulsion, soft gelatin capsule, sterile injectable liquid such as an ampoule or non-aqueous liquid suspension. Compounds of formula (I) may be administered topically, that is by non-systemic administration. This includes the application of a compound of formula (I) externally to the epidermis or the buccal cavity and the instillation of such a compound into the ear, eye and nose, such that the compound does not significantly enter the blood stream. In contrast, systemic administration refers to oral, intravenous, intraperitoneal and intramuscular administration. Formulations suitable for topical administration include liquid or semi-liquid preparations suitable for penetration through the skin to the site of inflammation such as liniments, lotions, creams, ointments or pastes, and drops suitable for administration to the eye, ear or nose. The active ingredient may comprise, for topical administration, from 0.001% to 10% w/w, for instance from 1% to 2% by weight of the formulation. It may however comprise as much as 10% w/w but preferably will comprise less than 5% w/w, more preferably from 0.1% to 1% w/w of the formulation. Lotions according to the present invention include those suitable for application to the skin or eye. An eye lotion may comprise a sterile aqueous solution optionally containing a bactericide and may be prepared by methods similar to those for the preparation of drops. Lotions or liniments for application to the skin may also include an agent to hasten drying and to cool the skin, such as an alcohol or acetone, and/or a moisturiser such as glycerol or an oil such as castor oil or arachis oil. Creams, ointments or pastes according to the present invention are semi-solid formulations of the active ingredient for external application. They may be made by mixing the active ingredient in finely divided or powdered form, alone or in solution or suspension in an aqueous or non-aqueous fluid, with the aid of suitable machinery, with a greasy or non-greasy base. The base may comprise hydrocarbons such as hard, soft or liquid paraffin, glycerol, beeswax, a metallic soap; a mucilage; an oil of natural origin such as almond, corn, arachis, castor or olive oil; wool fat or its derivatives or a fatty acid such as stearic or oleic acid together with an alcohol such as propylene glycol or a macrogel. The formulation may incorporate any suitable surface active agent such as an anionic, cationic or non-ionic surfactant such as a sorbitan ester or a polyoxyethylene derivative thereof. Suspending agents such as natural gums, cellulose derivatives or inorganic materials such as silicaceous silicas, and other ingredients such as lanolin, may also be included. Drops according to the present invention may comprise sterile aqueous or oily solutions or suspensions and may be prepared by dissolving the active ingredient in a suitable aqueous solution of a bactericidal and/or fungicidal agent and/or any other suitable preservative, and preferably including a surface active agent. The resulting solution may then be clarified by filtration, transferred to a suitable container which is then sealed and sterilised by autoclaving or maintaining at 98-100°C. for half an hour. Alternatively, the solution may be sterilised by filtration and transferred to the container by an aseptic technique. Examples of bactericidal and fungicidal agents suitable for inclusion in the drops are phenylmercuric nitrate or acetate (0.002%), benzalkonium chloride (0.01%) and chlorhexidine acetate (0.01%). Suitable solvents for the preparation of an oily solution include glycerol, diluted alcohol and propylene glycol. Compounds of formula (I) may be administered parenterally, that is by intravenous, intramuscular, subcutaneous intranasal, intrarectal, intravaginal or intraperitoneal administration. The subcutaneous and intramuscular forms of parenteral administration are generally preferred. Appropriate dosage forms for such administration may be prepared by conventional techniques. Compounds of formula (I) may also be administered by inhalation, that is by intranasal and oral inhalation administration. Appropriate dosage forms for such administration, such as an aerosol formulation or a metered dose inhaler, may be prepared by conventional techniques. For all methods of use disclosed herein for the compounds of formula (I), the daily oral dosage regimen will preferably be from about 0.1 to about 80 mg/kg of total body weight, preferably from about 0.2 to 30 mg/kg, more preferably from about 0.5 mg to 15mg. The daily parenteral dosage regimen about 0.1 to about 80 mg/kg of total body weight, preferably from about 0.2 to about 30 mg/kg, and more preferably from about 0.5 mg to 15mg/kg. The daily topical dosage regimen will preferably be from 0.1 mg to 150 mg, administered one to four, preferably two or three times daily. The daily inhalation dosage regimen will preferably be from about 0.01 mg/kg to about 1 mg/kg per day. It will also be recognised by one of skill in the art that the optimal quantity and spacing of individual dosages of a compound of formula (I) or a pharmaceutically acceptable salt thereof will be determined by the nature and extent of the condition being treated, the form, route and site of administration, and the particular patient being treated, and that such optimums can be determined by conventional techniques. It will also be appreciated by one of skill in the art that the optimal course of treatment, i.e., the number of doses of a compound of formula (I) or a pharmaceutically acceptable salt thereof given per day for a defined number of days, can be ascertained by those skilled in the art using conventional course of treatment determination tests. SYNTHETIC EXAMPLES General Synthetic Methods Method A - 2-(4-Cyanophenyl)-4-(4-fluorophenyl)-5-(4-pyridyl)-1H-imidazole To a solution of 2-(4-cyanophenyl)-4-(4-fluorophenyl)-N-1-hydroxy-5-(4-pyridyl)imidazole (4.5 g, 13.2 mmol) [See Method B, below] in DMF (50 mL) was added triethyl phosphite (3.4 mL, 20 mmol), and the resulting mixture was heated at 100 °C for 2 h. After cooling, the mixture was poured into H 2 O, and the solid which formed was collected by filtration, washed with H 2 O and dried in vacuo to afford the title compound (4.0 g, 89%). Recrystallisation from CH 2 Cl 2 /MeOH gave a white solid with a mp of 268-269 °C. Method B - 2-(4-Cyanophenyl)-4-(4-fluorophenyl)-1-N-hydroxy-5-(4-pyridyl)imidazole (a) 4-Fluoro-N-methoxy-N-methylbenzamide To a mixture containing methoxymethylamine hydrochloride (44 g, 0.45 mol) and triethylamine (138 mL, 0.99 mol) in CH 2 Cl 2 (500 mL) at 0 °C was added over 30 min, 4-fluorobenzoyl chloride (50 mL, 0.41 mol). The resulting mixture was allowed to warm to rt and stirring was continued for 30 min, at which time the mixture was poured into H 2 O and extracted with Et 2 O. The organic extract was washed with saturated aqueous NaCl and dried (MgSO 4 ). Removal of the solvent in vacuo afforded the title com-pound (80 g, 100%), which was used without further purification: 1 H NMR (CDCl 3 ): d 7.72 (dd, 2H); 7.06 (apparent t, 2H); 3.52 (s, 3H); 3.43 (s, 3H). (b) 4-Fluoro-2-(4-pyridyl)acetophenone A solution of lithium diisopropylamide was prepared at -78 °C in the usual manner from diisopropylamine (21 ml, 0.15 mol) and n-butyllithium (54 mL of 2.5 M solution in hexanes, 0.135 mol), and to this was added at -78 °C, 4-picoline (10 g, 0.108 mol). After stirring an additional 15 min at -78 °C., 4-fluoro-N-methoxy-N-methylbenzamide (20 g, 0.109 mol) was added, and the mixture was allowed to slowly warm to rt. The reaction mixture was poured into saturated aqueous NaCl and extracted with 4:1 THF/CH 2 Cl 2 , and the organic extract was dried (MgSO 4 ). The solvent was removed in vacuo, and to the oily brown residue was added Et 2 O. The title compound was obtained as a brown solid (16.8 g, 72%) which was recrystallised from Et 2 O/Hex: 1 H NMR (CDCl 3 ): d 8.55 (d, 2H); 8.03 (dd, 2H); 7.16 (m, 4H); 4.24 (s, 2H). (c) 4-Fluoro-2-hydroxyimino-2-(4-pyridyl)acetophenone The title compound was prepared using the same procedure (US 3,940,486) employed to prepare 2-hydroxyimino-2-(4-pyridyl)acetophenone, except using 4-fluoro-2-(4-pyridyl)acetophenone. (d) 2-(4-Cyanophenyl)-4-(4-fluorophenyl)-N-1-hydroxy-5-(4-pyridyl)imidazole - The title compound was prepared using the same procedure (US 3,940,486) employed to prepare 2-(t-butyl)-4-(phenyl)-N-1-hydroxy-5-(4-pyridyl)imidazole, except using 4-fluoro-2-hydroxyimino-2-(4-pyridyl)acetophenone and 4-cyanobenzaldehyde: 1 H NMR (CDCl 3 ): d 8.27 (d, 2H); 7.94 (d, 2H); 7.72 (d, 2H); 7.35 (d, 2H); 7.30 (dd, 2H); 6.96 (t, 2H). Method C - 2-(3,5-Dibromo-4-hydroxyphenyl)-4-(4-fluorophenyl)-5-(4-pyridyl)-1H-imidazole (a) 1-(4-fluorophenyl)-2-(4-pyridyl)-ethanediol To a stirring solution of 2.0 g (11.2 mmol) 4-(t-butyldimethylsilyloxy)methyl pyridine in 8 ml of THF at -20°C was added 14.7 mmol of lithium di- iso -propyl amide in THF. Thirty minutes later 4-fluorobenzaldehyde (1.66 g, 13.4 mmol) was added at which point the solution was allowed to warm slowly to rt. The reaction was quenched with NH 4 Cl and extracted with ether to afford the crude protected diol which following concentration was dissolved in THF and treated with 17 ml of a 1 molar solution of tetrabutylammonium fluoride in THF overnight. Standard aqueous workup afforded the crude diol which was further purified by column chromatography (hex/EtOAc) to yield 1.6 g (62%) of the titled material. (b) 1-(4-fluorophenyl)-2-(4-pyridyl)ethanedione Oxidation of 1-(4-fluorophenyl)-2-(4-pyridyl)ethanediol according to the oxalyl chloride method of Swern [J. Org. Chem., 44 , p 4148, 1979)] gave the titled dione following extractive workup and recrystallisation from hexanes m.p. 85-86.5°C. (c) 2-(3,5-Dibromo-4-hydroxyphenyl)-4-(4-fluorophenyl)-5-(4-pyridyl)-1H-imidazole To a solution of 1-(4-fluorophenyl)-2-(4-pyridyl)ethanedione (0.25 g, 1.1 mmol) and 3,5-dibromo-4-hydroxy-benzaldehyde (0.37 g, 1.3 mmol) in glacial acetic acid (5 mL) was added ammonium acetate (0.50 g, 6.5 mmol), and the resulting mixture was heated at reflux for 18 h. After cooling, the mixture was poured into H 2 O, and the pH was adjusted to neutral by the addition of 2.5 N NaOH. The solid which formed was collected by filtration, washed with H 2 O, dried in vacuo and purified by flash chromatography, eluting with a solvent gradient of 2-4% MeOH/CHCl 3 . The title compound was obtained as a tan solid (15 mg, 3%): ESMS ( m / z ): 488 (M + +H). Method D - 4-(4-Fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyridyl)-1H-imidazole The title compound was prepared using the same procedure as described in Method C, except using 4-(methylthio)-benzaldehyde: ESMS ( m / z ): 362 (M + +H). Method E - 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole To a solution of 4-(4-fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyridyl)-1H-imidazole (0.80 g, 2.2 mmol) [See Method D, above] in glacial acetic acid (15 mL) was added a solution of K 2 S 2 O 8 (0.72 g, 2.6 mmol) in H 2 O (20 mL). Additional glacial acetic acid (15 mL) was added to ensure homogeneity, and the resulting solution was stirred at rt for 18 h. The mixture was then poured into H 2 O, and the pH was adjusted to neutral by the addition of conc. NH 4 OH. The solid which formed was collected by filtration to afford the title compound (0.65 g, 78%) as a tan solid, which was recrystallised from MeOH: mp 250-252 °C. Examples Example 1 - 4-(4-Fluorophenyl)-N-1-hydroxy-5-(4-pyrimidinyl)-imidazole (a) 4-Fluoro-2-(4-pyrimidinyl)acetophenone The title compound was prepared using the same procedure as described in Method B, step (b) except using 4-methylpyrimidine. (b) 4-Fluoro-2-hydroxyimino-2-(4-pyrimidinyl)acetophenone The title compound was prepared using the same procedure described in Method B, step (c) except using 4-fluoro-2-(4-pyrimidinyl)acetophenone. (c) 4-(4-Fluorophenyl)-N-1-hydroxy-5-(4-pyrimidinyl)imidazole The title compound was prepared using the same procedure described in Method B, step (d) except using 4-fluorophenyl-2-hydroxyimino-2-(4-pyrimidinyl)acetophenone. Example 2 - 4-(4-Fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyrimidinyl)-1H-imidazole The title compound was prepared using the same procedure as described in Method A, except using 4-(4-fluorophenyl)-N-1-hydroxy-5-(4-pyrimidinyl)imidazole: CIMS (NH 3 , m / z ): 363 (M + +H). Example 3 - 4-(4-Fluorophenyl)-2-(4-methylsulfinylpheny)-5-(4-pyrimidinyl)-1H-imidazole The title compound was prepared using the same procedure described in Method E, except using 4-(4-fluorophenyl)-2-(4-methylthio)phenyl)-5-(4-pyrimidinyl)-1H-imidazole: CIMS (NH 3 , m / z ): 379 (M + +H). Example 4 - 4-(4-Fluorophenyl)-2-(4-methylsulfonylpheny)-5-(4-pyrimidinyl)-1H-imidazole To a solution of 4-(4-fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyrimidinyl)-1H-imidazole (0.10 g, 0.28 mmol) [See Examples 1 and 2, above] was added 3-chloroperbenzoic acid (50%, 0.15 g, 0.42 mmol). After stirring at rt for 72 h, the solvent was evaporated and the residue was partitioned between EtOAc and 2.5 N NaOH. The organic phase was washed with brine, dried (MgSO 4 ) and evaporated. The residue was triturated with EtOAc to afford the title compound as a white solid (0.50 g, 46%). CIMS (NH 3 , m / z ): 395 (M + +H). BIOLOGICAL EXAMPLES The cytokine-inhibiting effects of compounds of the present invention were determined by the following in vitro assays: 1. IL-1 - Human peripheral blood monocytes were isolated and purified from either fresh blood preparations from volunteer donors, or from blood bank buffy coats, according to the procedure of Colotta et al , J Immunol, 132 , 936 (1984). These monocytes (1x10 6 ) were plated in 24-well plates at a concentration of 1-2 million/ml per well. The cells were allowed to adhere for 2 hours, after which time non-adherent cells were removed by gentle washing. Test compounds were then added to the cells for 1 h before the addition of lipopolysaccharide (50 ng/ml), and the cultures were incubated at 37°C for an additional 24h. At the end of this period, culture supernatants were removed and clarified of cells and all debris. Culture supernatants were then immediately assayed for IL-1 biological activity, either by the method of Simon et al ., J. Immunol. Methods, 84 , 85, (1985) (based on ability of IL-1 to stimulate a Interleukin 2 producing cell line (EL-4) to secrete IL-2, in concert with A23187 ionophore) or the method of Lee et al ., J. ImmunoTherapy, 6 (1), 1-12 (1990) (ELISA assay). Compounds of formula (I) were shown to be inhibitors of in vitro IL-1 produced by human monocytes. 2. TNF - Human peripheral blood monocytes were isolated and purified from either blood bank buffy coats or plateletpheresis residues, according to the procedure of Colotta, R. et al ., J Immunol, 132 (2), 936 (1984). The monocytes were plated at a density of 1x10 6 cells/ml medium/well in 24-well multi-dishes. The cells were allowed to adhere for 1 hour after which time the supernatant was aspirated and fresh medium (1ml, RPMI-1640, Whitaker Biomedical Products, Whitaker, CA) containing 1% fetal calf serum plus penicillin and streptomycin (10 units/ml) added. The cells were incubated for 45 minutes in the presence or absence of a test compound at 1nM-10mM dose ranges (compounds were solubilised in dimethyl sulfoxide/ethanol, such that the final solvent concentration in the culture medium was 0.5% dimethyl sulfoxide/0.5% ethanol). Bacterial lipopolysaccharide ( E. coli 055:B5 [LPS] from Sigma Chemicals Co.) was then added (100 ng/ml in 10 ml phosphate buffered saline) and cultures incubated for 16-18 hours at 37°C in a 5% CO 2 incubator. At the end of the incubation period, culture supernatants were removed from the cells, centrifuged at 3000 rpm to remove cell debris. The supernatant was then assayed for TNF activity using either a radio-immuno or an ELISA assay, as described in WO92/10190 and by Becker et al ., J Immunol, 1991, 147 , 4307. Compounds of formula (I) were shown to be inhibitors of in vitro TNF production. IL-1 and TNF inhibitory activity does not seem to correlate with the property of the compounds of Formula (I) in mediating arachidonic acid metabolism inhibition, further the ability to inhibit production of prostaglandin and/or leukotriene synthesis, by nonsteroidal anti-inflammatory drugs with potent cyclooxygenase and/or lipoxygenase inhibitory activity does not mean that the compound will necessarily also inhibit TNF or IL-1 production, at non-toxic doses. 3. IL-8 - Primary human umbilical cord endothelial cells (HUVEC) (Cell Systems, Kirland, Wa) were maintained in culture medium supplemented with 15% fetal bovine serum and 1% CS-HBGF consisting of aFGF and heparin. The cells were then diluted 20-fold before being plated (250µl) into gelating coated 96-well plates. Prior to use, culture medium was replaced with fresh medium (200µl). Buffer or test compound (25µl, at concentrations between 1 and 10µM) was then added to each well in quadruplicate wells and the plates incubated for 6h in a humidified incubator at 37°C in an atmosphere of 5% CO 2 . At the end of the incubation period, supernatant was removed and assayed for IL-8 concentration using an IL-8 ELISA kit obtained from R&D Systems (Minneapolis, MN). All data were presented as mean value (ng/ml) of multiple samples based on the standard curve. IC 50 's where appropriate were generated by non-linear regression analysis. The compounds of formula (I), examples 5, 8b and 9, demonstrated a dose dependent reduction in the production of IL-8 (a 50-65% inhibition of IL-8).

Claims: A compound of formula (I): wherein R 1 is 4-pyrimidinyl, optionally substituted with one or two substituents each of which is independently selected from C 1-4 alkyl, halo, C 1-4 alkoxy, C 1-4 alkylthio, NH 2 , mono- or di-C 1-6 -alkylamino and a N-heterocyclyl ring which ring has from 5 to 7 members, and optionally contains an additional heteroatom selected from oxygen, sulfur and NR22; R 2 is selected from the group consisting of hydrogen, C 1-10 alkyl, or OR 12 when R 12 is hydrogen; R 3 is Q-(Y 1 ) t ; Q is a phenyl; t is an integer from 1 to 3; Z is oxygen or sulfur; n is 0 or an integer from 1 to 10; Y 1 is independently selected from hydrogen, C 1-5 alkyl, halo-substituted C 1-5 alkyl, halogenor -(CR 10 R 20 ) n Y 2 ; Y 2 is -OR 8 , -NO 2 , -S(O) m' R 11 , -SR 8 , -S(O) m' OR 8 , -S(O) m NR 8 R 9 , -NR 8 R 9 , -O(CR 10 R 20 ) n NR 8 R 9 , -C(O)R 8 , -CO 2 R 8 , -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , -ZC(O)R 8 , -CN, -C(Z)NR 8 R 9 , -NR 10 C(Z)R 8 , -C(Z)NR 8 OR 9 , -NR 10 C(Z)NR 8 R 9 , -NR 10 S(O) m R 11 , -N(OR 21 )C(Z)NR 8 R 9 , -N(OR 21 )C(Z)R 8 , -C(=NOR 21 )R 8 , -NR 10 C(=NR 15 )SR 11 , -NR 10 C(=NR 15 )NR 8 R 9 , -NR 10 C(=CR 14 R 24 )SR 11 , -NR 10 C(=CR 14 R 24 )NR 8 R 9 , -NR 10 C(O)C(O)NR 8 R 9 , -NR 10 C(O)C(O)OR 10 , -C(=NR 13 )NR 8 R 9 , -C(=NOR 13 )NR 8 R 9 , -C(=NR 13 )ZR 11 , -OC(Z)NR 8 R 9 , -NR 10 S(O) m CF 3 , -NR 10 C(Z)OR 10 , 5-(R 18 )-1,2,4-oxadiazol-3-yl or 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl; m' is 1 or 2; n' is an integer from 1 to 10; R 4 is phenyl, naphth-1-yl or naphth-2-yl which is optionally substituted by one or two substituents, each of which is independently selected, and which, for a 4-phenyl, 4naphth-1-yl or 5-naphth-2-yl substituent, is halo, cyano, -C(Z)NR 7 R 17 , -C(Z)OR 23 , -(CR 10 R 20 ) m COR 36 , -SR 5 , -SOR 5 , -OR 36 , halo-substituted-C 1-4 alkyl, C 1-4 alkyl, -ZC(Z)R 36 , -NR 10 C(Z)R 23 , or -(CR 10 R 20 ) m NR 10 R 20 ; and which, for other positions of substitution, is halo, cyano, -C(Z)NR 16 R 26 , -C(Z)OR 8 , -(CR 10 R 20 ) m COR 8 , -S(O) m R 8 , -OR 8 , halo-substituted-C 1-4 alkyl, C 1-4 alkyl, -(CR 10 R 20 ) m NR 10 C(Z)R 8 , -NR 10 S(O) m R 11 , -NR 10 S(O) m NR 7 R 17 wherein m is 1 or 2, -ZC(Z)R 8 or -(CR 10 R 20 ) m NR 16 R 26 ; m is 0, 1 or 2; R 5 is hydrogen, C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl or NR 7 R 17 , excluding the moieties -SR 5 being -SNR 7 R 17 and -SOR 5 being -SOH; R 6 is C 1-4 alkyl, halo-substituted-C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl or C 3-5 cycloalkyl; R 7 and R 17 is each independently selected from hydrogen and C 1-4 alkyl, or R 7 and R 17 together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 22 ; R 8 is hydrogen, heterocyclyl, heterocyclylC 1-10 alkyl or R 11 ; R 9 is hydrogen, C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylC 1-10 alkyl, heteroaryl or heteroarylC 1-10 alkyl, or R 8 and R 9 may together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 12 ; R 10 and R 20 is each independently selected from hydrogen and C 1-4 alkyl; R 11 is C 1-10 alkyl, halo-substituted C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 3-7 cycloalkyl, C 5-7 cycloalkenyl, aryl, arylC 1-10 alkyl, heteroaryl or heteroarylC 1-10 alkyl; R 12 is hydrogen, -C(Z)R 13 , optionally substituted C 1-4 alkyl, optionally substituted aryl or optionally substituted aryl-C 1-4 alkyl; R 13 is hydrogen, C 1-10 alkyl, cycloalkyl, heterocyclyl, aryl, arylC 1-10 alkyl, heteroaryl or heteroarylC 1-10 alkyl; R 14 and R 24 is each independently selected from hydrogen, alkyl, nitro and cyano; R 15 is hydrogen, cyano, C 1-4 alkyl, C 3-7 cycloalkyl or aryl; R 16 and R 26 is each independently selected from hydrogen or optionally substituted C 1-4 alkyl, optionally substituted aryl or optionally substituted aryl-C 1-4 alkyl, or together with the nitrogen which they are attached form a heterocyclic ring of 5 to 7 members which ring optionally contains an additional heteroatom selected from oxygen, sulfur and NR 12 ; R 18 and R 19 is each independently selected from hydrogen, C 1-4 alkyl, substituted alkyl, optionally substituted aryl, and optionally substituted arylC 1-10 alkyl; or together denote an oxygen or sulfur; R 21 is hydrogen, a pharmaceutically acceptable cation, C 1-10 alkyl, C 3-7 cycloalkyl, aryl, aryl C 1-4 alkyl, heteroaryl, heteroarylC 1-10 alkyl, heterocyclyl, aroyl, or C 1-10 alkoyl; R 22 is R 10 or C(Z)-C 1-4 alkyl; R 23 is C 1-4 alkyl, halo-substituted-C 1-4 alkyl, or C 3-5 cycloalkyl; R 36 is hydrogen or R 23 ; as used herein halo refers to all halogens, that is chloro, fluoro, bromo and iodo; C 1-10 alkyl or alkyl refers to both straight and branched chain radicals of 1 to 10 carbon atoms, unless the chain length is otherwise limited; aryl refers to phenyl and naphthyl; heteroaryl refers to (on its own or in any combination, such as heteroaryloxy) a 5-10 membered aromatic ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O and S; heterocyclic (on its own or in any combination, such as heterocyclylalkyl) refers to a saturated or wholly or partially unsaturated 4-10 membered ring system in which one or more rings contain one or more heteroatoms selected from the group consisting of N, O, or S; aroyl refers to a C(O)Ar, wherein Ar is as phenyl, naphthyl, or aryl alkyl derivatives, alkoyl refers to a C(O)C 1-10 alkyl wherein the alkyl is as defined above; sulfinyl refers to the oxide (SO) of the corresponding sulfide whilst the term "thio" refers to the sulfide; or a pharmaceutically acceptable salt thereof. A compound as claimed in claim 1 wherein the substituent Y 1 is selected from halogen, C 1-5 alkyl and -(CR 10 R 20 ) n Y 2 wherein Y 2 is -OR 8 , -NO 2 , -S(O) m' R 11 , -SR 8 , -S(O) m NR 8 R 9 ; -NR 8 R 9 , -O(CR 10 R 20 ) n NR 8 R 9 , -C(O)R 8 , -CO 2 R 8 , -CO 2 (CR 10 R 20 ) n' CONR 8 R 9 , -CN; -C(Z)NR 8 R 9 , -NR 10 S(O) m R 11 , -NR 10 C(Z)R 8 , -NR 10 C(Z)NR 8 R 9 , -C(Z)NR 8 OR 9 , -N(OR 21 )C(Z)NR 8 R 9 , -NR 10 C(=NR 15 )NR 8 R 9 , -C(=NOR 13 )NR 8 R 9 , 5-(R 18 )-1,2,4-oxadiazol-3-yl or 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl. A compound as claimed in claim 1 or claim 2 wherein Y 1 is -(CR 10 R 20 ) n Y 2 and n is 0 or 1 and Y 2 is OH, -S(O) m' R 11 , -SR 8 , -NR 8 R 9 , -CO 2 R 8 , -S(O) m NR 8 R 9 , -NR 10 S(O) m R 11 , 5-(R 18 )-1,2,4-oxadiazol-3-yl or 4-(R 12 )-5-(R 18 R 19 )-4,5-dihydro-1,2,4-oxadiazol-3-yl. A compound according to any one of claims 1 to 3 in which R 4 is phenyl or phenyl substituted at the 4-position with fluoro and/or substituted at the 3-position with fluoro, chloro, C 1-4 alkoxy, methane-sulfonamido or acetamido. A compound according to claim 1 selected from: 4-(4-Fluorophenyl)-2-(4-methylthiophenyl)-5-(4-pyrimidinyl)-1H-imidazole; 4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyrimidinyl)-1H-imidazole; 4-(4-Fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyrimidinyl)-1H-imidazole; and pharmaceutically acceptable salts thereof. A process for preparing a compound of formula (I) as defined in any one of claims 1 to 5 which process comprises: (i) condensing an α-diketone of formula (II): R 1 COCOR 4 wherein R 1 and R 4 are as defined in claim 1, or an equivalent thereof, with an aldehyde of the formula (III): R 3 CHO wherein R 3 is as defined in claim 1, or an equivalent thereof, and, if necessary, with ammonia or a source thereof, under imidazole-ring forming conditions; (ii) treating an α-hydroxyketone compound of formula (IIA): R'CHOHCOR" wherein one of R' and R" is R 1 and the other is R 4 , a suitably protected derivative thereof or the α-hydroxy-oxime or α-haloketone derivative thereof, with an oxidising agent capable of converting said compound into the corresponding α-diketone, in the presence of an aldehyde of formula (III) or an equivalent thereof, and a source of ammonia; (iii) treating an amidine of formula (IV): R 3 C(=NH)NHR 2 wherein R 2 and R 3 are as defined in claim 1, or a salt thereof, with a reactive ester of an α-hydroxyketone of formula (IIA) or the corresponding α-haloketone, in an inert solvent, at a moderately elevated temperature and, if necessary, in the presence of a suitable condensation agent; (iv) treating an iminoether of formula (V): R 3 C=NOR wherein R 3 is as defined in claim 1 and R is C 1-10 alkyl, aryl or aryl C 1-4 alkyl, with an α-aminoketone of the formula (VI): R'CHNH 2 COR" wherein one of R' and R" is R 1 and the other is R 4 in a suitable solvent; (v) treating the anion of an amide of formula (VII): R 1 CH 2 NR 2 COR 3 wherein R 1 and R 3 are as defined in claim 1, and R 2 is as defined in claim 1 other than hydrogen, with: (a) a nitrile of the formula (VIII): R 4 CN wherein R 4 is as defined in claim 1, or (b) an excess of an acyl halide, of the formula (IX): R 4 COHal wherein R 4 is as defined in claim 1 and Hal is halogen, or a corresponding anhydride, to give a bis -acylated intermediate which is then treated with a source of ammonia; (vi) treating a compound of formula (X): R'COCHR"X c COR 3 wherein R', R" and R 4 are as hereinbefore defined and X c is O or NH, with a source of ammonia, or cyclising the corresponding Schiffs base, formed by treating the compound of formula (X) with an amine R 2 NH 2 ; (vii) coupling a suitable derivative of a compound of formula (XI): wherein: T 2 is a nitrogen protecting group or R 2 , other than hydrogen; and T 1 is hydrogen, T 3 is R 3 and T 4 is R 4 ; T 1 is R 1 , T 3 is hydrogen and T 4 is R 4 ; or T 1 is R 1 , T 3 is R 3 and T 4 is hydrogen, in which R 1 , R 2 , R 3 and R 4 are as defined in claim 1; with: (i) when T 1 is hydrogen, a suitable derivative of the heteroaryl ring R 1 H, under ring coupling conditions, to effect coupling of the heteroaryl ring R 1 to the imidazole nucleus at position 5; (ii) when T 3 is hydrogen, a suitable derivative of the R 3 group R 3 H, under ring coupling conditions, to effect coupling of the R 3 group to the imidazole nucleus at position 2; or (iii) when T 4 is hydrogen, a suitable derivative of the aryl ring R 4 H, under ring coupling conditions, to effect coupling of the aryl ring R 4 to the imidazole nucleus at position 4; (viii) treating a compound of formula (XI), wherein T 1 is hydrogen, with an N-acyl heteroaryl salt, to give an intermediate in which the heteroaryl ring is attached to the imidazole nucleus and is present as a 1,4-dihydro derivative thereof, which intermediate is then subjected to oxidative-deacylation conditions; and thereafter and if necessary carrying out all or any of the additional steps of removing a protecting group, transforming an initially obtained compound of formula (I) into a further compound of formula (I) or forming a pharmaceutically acceptable salt. A compound as claimed in any one of claims 1 to 5, or a pharmaceutically acceptable salt thereof, for use in therapy. The use of a compound as claimed in any one of claims 1 to 5, or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for treating a cytokine-mediated disease state. A pharmaceutical composition comprising an effective, non-toxic amount of a compound as claimed in any one of claims 1 to 5, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent. The compound 4-(4-fluorophenyl)-N-1-hydroxy-5-(4-pyrimidinyl)-imidazole.

Inventors: ADAMS JERRY LEROY, GALLAGHER TIMOTHY F, LEE JOHN C, WHITE JOHN RICHARD, ADAMS, JERRY LEROY, GALLAGHER, TIMOTHY F., LEE, JOHN C, WHITE, JOHN RICHARD, Adams, Jerry Leroy, SmithKline Beecham Pharm., Gallagher, Timothy F., SmithKline Beecham Phar., Lee, John C, SmithKline Beecham Pharm., White, John Richard, SmithKline Beecham Pharm.
Applicants: SMITHKLINE BEECHAM CORP, SMITHKLINE BEECHAM CORPORATION
Application year: 1993
Main classification: C07D403
IPC codes: C07D403