Background to the Invention The leukotriene cascade of arachadonic acid is a key mechanism in many inflammatory and allergic disease states. The dihydroxy fatty acid leukotriene B4 (LTB4), produced by this cascade, is a key pro-inflammatory mediator. LTB4 stimulates adhesion of circulating neutrophils to vascular endothelium, directs their migration toward sites of inflammation, and induces secretion of further inflammatory mediators. (For reviews see R. A. Lewis et al, N. Engl. J. Med. 1990,323,645-655 and M.-Q. Zhang, Curr. Med. Chem. 1997,4,67-78.) Leukotriene-A4 hydrolase (LTA4-hydrolase) (EC 3.3.2.6) is an enzyme that catalyses the final and rate limiting step in the synthesis of LTB4. Inhibition of LTA4 hydrolase selectively blocks the biosynthesis of LTB4 which may provide an advantage over current inhibitors, such as those of 5-lipoxygenase, that block earlier in the leukotriene cascade and as a result are less selective.

Disease states associated with elevated levels of LTB4, and which are therefore considered to be responsive to inhibition of intracellular leukotriene-A4 hydrolase activity include asthma, inflammatory bowel disease, psoriasis and arthritis.

Peptidomimetic compounds, such as bestatin, captopril and kelatorphan exhibit LTA4 hydrolase inhibitory activity against isolated enzyme (T. D. Penning et al, Biorg.

Med. Chem. Lett., 1995,5, p2517-2522). However, these compounds are unable to effectively penetrate cells and hence have little anti-inflammatory activity. There is therefore a need in the art for compounds which are capable of inhibiting intracellular LTA4 hydrolase activity.

Brief Description of the invention This invention is based on the finding that certain esters and thioesters are capable of inhibiting intracellular LTA4 hydrolase activity, resulting in attenuation of LTB4 biosynthesis. Those esters and thioesters are therefore of use for the treatment of diseases responsive to such inhibiton, for example inflammatory and allergic conditions including asthma, rheumatoid arthritis, osteoarthritis, ulcerative colitis, contact and atopic dermatitis, psoriasis, inflammatory bowel disease and Crohn's disease.

In our earlier international patent application PCT/GB97/02398 (WO 98/11063), there is disclosed the use of the same class of esters and thioesters as inhibitors of the proliferation of rapidly dividing cells, and thus as agents for the treatment, inter alia, of cancer. However, the present utility as inhibitors of LTA4 hydrolase is unrelated to and not predictable from the teaching of that application.

A few patent publications (WO 92/09563, US 5183900, US 5270326, EP-A- 0489577, EP-A-0489579, WO 93/09097, WO 93/24449, WO 94/25434, WO 94/25435, WO 95/04033, WO 95/19965, and WO 95/22966) include within their generic disclosure carboxylate ester compounds having matrix metalloproteinase inhibitory activity. In accordance with the present invention, such compounds are now recognised to have LTA4 hydrolase activity, but that activity is not suggested by, or predictable from, those publications.

WO 95/04033 discloses N4-hydroxy-N'- (1- (S)-methoxycarbonyl-2, 2-dimethylpropyl)- 2-(R)-(4-chlorophenylpropyl)(R)-(4-chlorophenylpropyl) succinamide as an intermediate for the preparation of the corresponding methylamide MMP inhibitor. In addition, Int. J. Pept. Protein Res.

(1996), 48 (2), 148-155 discloses the compound Ph-CH2CH (CO-lle-OtBu) CH2CONHOH as an intermediate in the preparation of compounds which are inhibitors of neurotensin-degrading enzymes. However, those two appear to be the only specific known carboxylate ester compounds of the kind with which this invention is concerned.

Detailed Description of the invention In its broadest aspect, the present invention provides a method for treatment of mammals suffering diseases responsive to inhibition of intracellular leukotriene-A4 hydrolase activity, comprising administering to the mammal suffering such disease an amount of a compound of general formula (I) or a pharmaceutieatty acceptable salt hydrate or solvate thereof sufficient to inhibit such activity: wherein R is hydrogen or (Cl-C6) alkyl; R, is hydrogen; (Cl-C6) alkyl ; (C2-C6)alkenyl; phenyl or substituted phenyl; phenyl (C,-C6) alkyl or substituted phenyl (C,-C6) alkyl; phenyl (C2-C6) alkenyl or substituted phenyl (C2-C6) alkenyl heterocyclyl or substituted heterocyclyl; heterocyclyi (C,-C6) alkyl or substituted heterocyclyl (C,-C6) alkyl; a group BSOnA-wherein n is 0,1 or 2 and B is hydrogen or a (Cl-C6) alkyl, phenyl, substituted phenyl, heterocyclyl substituted heterocyclyl, (C,-C6) acyl, phenacyl or substituted phenacyl group, and A represents (C,-C6) alkylene; hydroxy or (C,-C6) alkoxy; amino, protected amino, acylamino, (C,-C6) alkylamino or di-(C1- C6)alkylamino; mercapto or (C,-C6) alkylthio; amino (C,-C6) alkyl, (C,-C6) alkylamino (C,-C6) alkyl, di (C,-C6) alkylamino (C,- C6) alkyl, hydroxy (C,-C6) alkyl, mercapto (C,-C6) alkyl or carboxy (C,-C6) alkyl wherein the amino-, hydroxy-, mercapto-or carboxyl-group are optionally protected or the carboxyl-group amidated; lower alkyl substituted by carbamoyl, mono (C,-C6alkyl) carbamoyl, di (C1- C6alkyl) carbamoyl, di (C,-C6alkyl) amino, or carboxy-C1-C6alkanoylamino ; or a cycloalkyl, cycloalkenyl or non-aromatic heterocyclic ring containing up to 3 heteroatoms, any of which may be (i) substituted by one or more substituents selected from C1-C6 alkyl, C2-C6 alkenyl, halo, cyano (-CN),-CO2H,-CO2R,- CONH2,-CONHR,-CON (R) 2,-OH,-OR, oxo-,-SH,-SR,-NHCOR, and- NHCO2R wherein R is C,-C6 alkyl or benzyl and/or (ii) fused to a cycloalkyl or heterocyclic ring; R2 is a C,-C, 2 alkyl, C2-C12alkenyl, C2-C12alkenyl, phenyl(C1-C6alkyl)-, heteroaryl(C1-C6alkyl)-, phenyl (C2-C6 alkenyl)-, heteroaryl(C2-C6alkenyl)-, phenyl (C2-C6 alkynyl)-,<BR> heteroaryl (C2-C6 alkynyl)-, cycloalkyl(C1-C6alkyl)-, cycloalkyl (C2-C6 alkenyl)-,<BR> cycloalkyl (C2-C6 alkynyl)-, cycloalkenyl(C1-C6alkyl)-, cycloalkenyl (C2-C6 alkenyl)-, cycloalkenyl(C2-C6alkynyl)-, phenyl (C,-C6 alkyl) O (C,-C6 alkyl)-, or heteroaryl (C,-C6 alkyl) O (C,-C6 alkyl)-group, any one of which may be optionally substituted by C1-C6alkyl, C,-C6 alkoxy, halo, cyano (-CN), phenyl or heteroaryl, or phenyl or heteroaryl substituted by C1-C6alkyl, C1-C6alkoxy, halo, or cyano (-CN); R3 is the characterising group of a natural or non-natural a amino acid in which any functional groups may be protected; and R4 is an ester or thioester group, or a pharmaceutically acceptable salt, hydrate or solvate thereof.

In another broad aspect of the invention, there is provided the use of a compound of formula (I) as defined in the immediately preceding paragraph, in the preparation of a pharmaceutical composition treatment of mammals suffering diseases responsive to inhibition of intracellular leukotriene-A4 hydrolase activity, In one particular aspect of the invention, the compound used is one of general formula (I) above wherein R, R"R2, R3 and R4 are as defined above with reference to formula (I), or a pharmaceutically acceptable salt, hydrate or solvate thereof, PROVIDED THAT: (i) when R and R, are hydrogen, R2 is 4-chlorophenylpropyl, and R3 is tert- butyl, then R4 is not a methyl carboxylate ester group; and (ii) when R and R, are hydrogen, R2 is phenylmethyl, and R3 is 1- methylprop-1-yl, then R4 is not a tert-butyl carboxylate ester group.

In another particular aspect of the invention, the compound used is one of general formula (I) above wherein: R, R, and R4 are as defined above with reference to formula (I) R2 is C2-C12alkenyl,C2-C12alkynyl,alkyl, biphenyl (C,-C6 alkyl)-, phenylheteroaryl (C,-C6 alkyl)-, heteroarylphenyl (C,-C6 alkyl)-, biphenyl (C2-C6 alkenyl)-, phenylheteroaryl (C2-C6 alkenyl)-, heteroarylphenyl (C2-C6 alkenyl)-, phenyl (C2-C6 alkynyl)-, heteroaryl (C2-C6 alkynyl)-, biphenyl (C2-C6 alkynyl)-, phenylheteroaryl (C2-C6 alkynyl)-,<BR> <BR> <BR> <BR> <BR> heteroarylphenyl (C2-C6alkynyl)-, phenyl (C,-C6 alkyl) O (C,-C6 alkyl)-, or heteroaryl (C,-C6 alkyl) O (C,-C6 alkyl)-, any one of which may be optionally substituted on a ring carbon atom by C,-C6 alkyl, C,-C6 alkoxy, halo, or cyano (-CN); and R3 is C,-C6 alkyl, optionally substituted benzyl, optionally substituted phenyl, optionally substituted heteroaryl; or the characterising group of a natural a amino acid, in which any functional group may be protected, any amino group may be acylated and any carboxyl group present may be amidated; or a heterocyclic (C,-C6) alkyl group, optionally substituted in the heterocyclic ring; or a pharmaceutically acceptable salt, hydrate or solvate thereof.

As used herein the term" (C,-C6) alkyl"or"lower alkyl"means a straight or branched chain alkyl moiety having from 1 to 6 carbon atoms, including for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl and n-hexyl.

The term" (C2-C6) alkenyl" means a straight or branched chain alkenyl moiety having from 2 to 6 carbon atoms having at least one double bond of either E or Z stereochemistry where applicable. This term would include, for example, vinyl, allyl, 1-and 2-butenyl and 2-methyl-2-propenyl.

The term"C2-C6 alkynyl"refers to straight chain or branched chain hydrocarbon groups having from two to six carbon atoms and having in addition one triple bond.

This term would include for example, ethynyl, 1-propynyl, 1-and 2-butynyl, 2-methyl- 2-propynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl and 5-hexynyl.

The term"cycloalkyl"means a saturated alicyclic moiety having from 3-8 carbon atoms and includes, for example, cyclohexyl, cyclooctyl, cycloheptyl, cyclopentyl, cyclobutyl and cyclopropyl.

The term"cycloalkenyl"means an unsaturated alicyclic moiety having from 4-8 carbon atoms and includes, for example, cyclohexenyl, cyclooctenyl, cycloheptenyl, cyclopentenyl, and cyclobutenyl. In the case of cycloalkenyl rings of from 5-8 carbon atoms, the ring may contain more than one double bond.

The term"aryl"means an unsaturated aromatic carbocyclic group which is moncyclic (eg phenyl) or polycyclic (eg naphthyl).

The unqualified term"heterocyclyl"or"heterocyclic"means (i) a 5-7 membered heterocyclic ring containing one or more heteroatoms selected from S, N and O, and optionally fused to a benzene ring, including for example, pyrrolyl, furyl, thienyl, piperidinyl, imidazolyl, oxazolyl, thiazolyl, thiadiazolyl, pyrazolyl, pyridinyl, pyrrolidinyl, pyrimidinyl, morpholinyl, piperazinyl, indolyl, benzimidazolyl, maleimido, succinimido, phthalimido, 4-triazolidin-4-yl, 3,4,4- trimethyl-2,5-dioxo-1-imidazolidinyl, 2-methyl-3,5-dioxo-1,2,4-oxadiazol-4-yl, 3- methyl-2,4,5-trioxo-1-imidazolidinyl, 2,5-dioxo-3-phenyl-1-imidazolidinyl, 2-oxo-1- pyrrolidinyl, 2,5-dioxo-1-pyrrolidinyl or 2, 6-dioxopiperidinyl, or (ii) a naphththalimido (ie [fXisoindol-2-yl), 1,3-dihydro-1-oxo-2H- benz [fgisoindol-2-yl, 1,3-dihydro-1, 3-dioxo-2H-pyrrolo [3,4-b] quinolin-2-yl, or 2,3- dihydro-1,3-dioxo-1 H-benz [d, e] isoquinolin-2-yl group.

The term"heteroaryl"means a 5-7 membered substituted or unsubstituted aromatic heterocycle containing one or more heteroatoms. Illustrative of such rings are thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, pyrazolyl, isoxazolyl, isothiazolyl, trizolyl, thiadiazolyl, oxadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl.

The term"ester"or"esterified carboxyl group"means a group RgO (C=O)- in which Rg is the group characterising the ester, notionally derived from the alcohol RgOH.

The term"thioester"means a group R9S (C=O)- or RgS (C=S)- or RgO (C=S)-in which Rg is the group characterising the thioester, notionally derived from the alcohol RgOH or the thioalcohol RgSH.

Unless otherwise specified in the context in which it occurs, the term"substituted"as applied to any moiety herein means substituted with up to four substituents, each of which independently may be (C,-C6) alkyl, (C,-C6) alkoxy, hydroxy, mercapto, (C,- C6) alkylthio, amino, halo (including fluoro, chloro, bromo and iodo), nitro, trifluoromethyl,-COOH,-CONH2,-CN,-COORA,-CONHRAor-CONHRARA wherein RA is a (C,-C6) alkyl group or the residue of a natural alpha-amino acid.

The term"side chain of a natural or non-natural alpha-amino acid"means the group R'in a natural or non-natural amino acid of formula NH2-CH (R')-COOH.

Examples of side chains of natural alpha amino acids include those of alanine, arginine, asparagine, aspartic acid, cysteine, cystine, glutamic acid, histidine, 5- hydroxylysine, 4-hydroxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, a-aminoadipic acid, a-amino-n-butyric acid, 3,4-dihydroxyphenylalanine, homoserine, a- methylserine, ornithine, pipecolic acid, and thyroxine.

Natural alpha-amino acids which contain functional substituents, for example amino, carboxyl, hydroxy, mercapto, guanidyl, imidazolyl, or indolyl groups in their characteristic side chains include arginine, lysine, glutamic acid, aspartic acid, tryptophan, histidine, serine, threonine, tyrosine, and cysteine. When R3 in the compounds of the invention is one of those side chains, the functional substituent may optionaily be protected.

The term"protected"when used in relation to a functional substituent in a side chain of a natural alpha-amino acid means a derivative of such a substituent which is substantially non-functional. For example, carboxyl groups may be esterified (for example as a C,-C6 alkyl ester), amino groups may be converted to amides (for example as a NHCOC,-C6 alkyl amide) or carbamates (for example as an NHC (=O) OC,-C6 alkyl or NHC (=O) OCH2Ph carbamate), hydroxyl groups may be converted to ethers (for example an OC,-C6 alkyl or a O (C,-C6 alkyl) phenyl ether) or esters (for example a OC (=O) C,-C6 alkyl ester) and thiol groups may be converted to thioethers (for example a tert-butyl or benzyl thioether) or thioesters (for example a SC (=O) C,-C6 alkyl thioester).

Examples of side chains of non-natural alpha amino acids include those referred to below in the discussion of suitable R3 groups for use in compounds of the present invention.

Salts of the compounds used in the invention include physiologically acceptable acid addition salts for example hydrochlorides, hydrobromides, sulphates, methane sulphonates, p-toluenesulphonates, phosphates, acetates, citrates, succinates, lactates, tartrates, fumarates and maleates. Salts may also be formed with bases, for example sodium, potassium, magnesium, and calcium salts.

There are several chiral centres in the compounds used according to the invention because of the presence of asymmetric carbon atoms. The presence of several asymmetric carbon atoms gives rise to a number of diastereomers with R or S stereochemistry at each chiral centre. For example, in the compounds used in the invention, the C atom carrying the hydroxamic acid and R, groups may be in the R or S configuration, the C atom carrying the R2 group may be predominantly in the R configuration, and the C atom carrying the R3 and R4 groups may be in either the R or S configuration, with the predominantly S configuration presently preferred.

As mentioned above, compounds of formula (I) above, and those of formula (I) excluded by the provisos in the definition of formula (i) above, are useful in human or veterinary medicine since they are inhibitors of intracellular leukotriene-A4 hydrolase activity. The utility of the invention therefore lies in the treatment of inflammatory and alergic conditions, such as asthma, rheumatoid arthritis, osteoarthritis, ulcerative colitis, contact and atopic dermatitis, psoriasis, multiple sclerosis, inflammatory bowel disease and Crohn's disease.

The compounds with which the invention is concerned may be prepared for administration by any route consistent with their pharmacokinetic properties.

Orally administrable compositions may be in the form of tablets, capsules, powders, granules, lozenges, liquid or gel preparations, such as oral, topical, or sterile parenteral solutions or suspensions. Tablets and capsules for oral administration may be in unit dose presentation form, and may contain conventional excipients such as binding agents, for example syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinyl-pyrrolidone; fillers for example lactose, sugar, maize-starch, calcium phosphate, sorbitol or glycine; tabletting lubricant, for example magnesium stearate, talc, polyethylene glycol or silica; disintegrants for example potato starch, or acceptable wetting agents such as sodium lauryl sulphate. The tablets may be coated according to methods well known in normal pharmaceutical practice. Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, for example sorbitol, syrup, methyl cellulose, glucose syrup, gelatin hydrogenated edible fats; emulsifying agents, for example lecithin, sorbitan monooleate, or acacia; non-aqueous vehicles (which may include edible oils), for example almond oil, fractionated coconut oil, oily esters such as glycerine, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid, and if desired conventional flavouring or colouring agents.

For topical application to the skin, the drug may be made up into a cream, lotion or ointment. Cream or ointment formulations which may be used for the drug are conventional formulations well known in the art, for example-as described in standard textbooks of pharmaceutics such as the British Pharmacopoeia.

The active ingredient may also be administered parenterally in a sterile medium.

Depending on the vehicle and concentration used, the drug can either be suspended or dissolve in the vehicle. Advantageously, adjuvants such as a local anaesthetic, preservative and buffering agents can be dissolved in the vehicle.

Clinically safe and effective dosages for the compounds with which the invention is concerned will be determined by clinical trials, as is required by the regulatory authorities in the art. It will be understood that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, rate of excretion, drug combination and the severity of the particular disease undergoing therapy.

In the compounds used in the invention, examples of substituents R, to R4 are given below: The group R, R, may be, for example, hydrogen, methyl, ethyl, n-propyl, n-butyl, isobutyl, hydroxyl, methoxy, allyl, phenylpropyl, phenylprop-2-enyl, thienylsulphanylmethyl, thienylsulphinylmethyl, or thienylsulphonylmethyl; or Cr-C4 alkyl, eg methyl, ethyl n-propyl or n-butyl, substituted by a phthalimido, 2,4-triazolidin-4-yl, 3-methyl-2, 5-dioxo-1- imidazolidinyl, 3,4,4-trimethyl-2, 5-dioxo-1-imidazolidinyl, 2-methyl-3, 5-dioxo- 5-trioxo-1-imidazolidinyl, 2,5-dioxo-3- phenyl-1-imidazolidinyl, 2-oxo-1-pyrrolidinyl, 2,5-dioxo-1-pyrrolidinyl or 2,6- dioxopiperidinyl, 5,5-dimethyl-2, 4-dioxo-3-oxazolidinyl, hexahydro-1,3- dioxopyrazolo [1,2, a] [1,2,4]-triazol-2-yl, or a naphththalimido (ie 1,3-dihydro- 1,3-dioxo-2H-benz [f] isoindol-2-yl), 1,3-dihydro-1-oxo-2H-benz [f]isoindol-2-yl, [3,4-b] quinolin-2-yl, or 2,3-dihydro-1,3-dioxo- 1 H-benz [d, e] isoquinolin-2-yl group; or cyclohexyl, cyclooctyl, cycloheptyl, cyclopentyl, cyclobutyl, cyclopropyl, tetrahydropyranyl or morpholinyl.

Presently preferred R, groups include n-propyl, allyl, hydroxy, methoxy and thienylsulfanylmethyl.

The group E2 R2 may for example be C3-C6alkenylorC3-C6alkynyl;C1-C12alkyl, phenyl(C,-C6 alkyl)-, phenyl (C3-C6 alkenyl)-or phenyl (C3-C6 alkynyl)- optionally substituted in the phenyl ring; heteroaryi (C,-C6 alkyl)-, heteroaryl (C3-C6 alkenyl)-or heteroaryl (C3-C6 alkynyl)-optionally substituted in the heteroaryl ring; 4-phenylphenyl (C,-C6 alkyl)-, 4-phenylphenyl (C3-C6 alkenyl)-, 4- phenylphenyl (C3-C6 alkynyl)-, 4-heteroarylphenyl (C,-C6 alkyl)-, 4- heteroarylphenyl (C3-C6 alkenyl)-, 4-heteroarylphenyl (C3-C6 alkynyl)-, optionally substituted in the terminal phenyl or heteroaryl ring; phenoxy (C,-C6 alkyl)-or heteroaryloxy (C,-C6 alkyl)-optionally substituted in the phenyl or heteroaryl ring; Specific examples of such groups include methyl, ethyl, n-and iso-propyl, n-, iso- and tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-nonyl, n-decyl, prop-2-yn-1-yl, 3- phenylprop-2-yn-1-yl, 3- (2-chlorophenyl) prop-2-yn-1-yl, phenylpropyl, 4- chlorophenylpropyl, 4-methylphenylpropyl, 4-methoxyphenylpropyl, phenoxybutyl, 3- (4-pyridylphenyl) propyl-, 3- (4- (4-pyridyl) phenyl) prop-2-yn-1-yl, 3- (4- phenylphenyl) propyl-, 3- (4-phenyl) phenyl) prop-2-yn-1-yl and 3- [ (4- chlorophenyl) phenyl] propyl-, cyclopentylmethyl, and benzyl.

Presently preferred R2 groups include isobutyl, n-hexyl, cyclopentylmethyl, benzyl, and 3- (2-chlorophenyl) prop-2-yn-1-yl.

The group B3 R3 may for example be C,-C6 alkyl, phenyl, 2,-3-, or 4-hydroxyphenyl, 2,-3-, or 4-methoxyphenyl, 2-or 3-thienyl, 2,-3-, or 4-pyridylmethyl, benzyl, 2,-3-, or 4-hydroxybenzyl, 2,-3-, or 4-benzyloxybenzyl, or 4-C1-C6 alkoxybenzyl, or benzyloxy (C,-C6alkyl)- group; or the characterising group of a natural a amino acid, in which any functional group may be protected, any amino group may be acylated and any carboxyl group present may be amidated; or a group- [Alk] nR6 where Alk is a (C,-C6) alkyl or (C2-C6) alkenyl group optionally interrupted by one or more -O-, or-S-atoms or-N (R7)-groups [where R7 is a hydrogen atom or a (C,-C6) alkyl group], n is 0 or 1, and R6 is an optionally substituted cycloalkyl or cycloalkenyl group; or a benzyl group substituted in the phenyl ring by a group of formula- OCH2COR8 where R8 is hydroxyl, amino, (C,-C6) alkoxy, phenyl (C,-C6) alkoxy, (C,-C6) alkylamino, di ((C1-C6)alkyl) amino, phenyl (C1-C6) alkylamino, the residue of an amino acid or acid halide, ester or amide derivative thereof, said residue being linked via an amide bond, said amino acid being selected from glycine, oc or ß alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, tryptophan, serine, threonine, cysteine, methionine, asparagine, glutamine, lysine, histidine, arginine, glutamic acid, and aspartic acid; or a heterocyclic (C,-C6) alkyl group, either being unsubstituted or mono-or di- substituted in the heterocyclic ring with halo, nitro, carboxy, (C,-C6) alkoxy, cyano, (C,-C6) alkanoyl, trifluoromethyl (C,-C6) alkyl, hydroxy, formyl, amino, (C,-C6) alkylamino, di-(C1-C6)alkylamino, mercapto, (C,-C6) alkylthio, hydroxy (C,-C6) alkyl, mercapto (C,-C6) alkyl or (C,-C6) alkylphenylmethyl; or a group-CRaRbRc in which: each of Ras Rb and Rc is independently hydrogen, (C-C6) alkyl, (C2- C6) alkenyl, (C2-C6) alkynyl, phenyl (C,-C6) alkyl, (C3-C8) cycloalkyl ; or Rc is hydrogen and Ra and Rb are independently phenyl or heteroaryl such as pyridyl; or Rc is hydrogen, (C,-C6) alkyl, (C2-C6) alkenyl, (C2-C6) alkynyl, phenyl (C,- C6) alkyl, or (C3-C8) cycloalkyl, and Ra and Rb together with the carbon atom to which they are attached form a 3 to 8 membered cycloalkyl or a 5-to 6-membered heterocyclic ring; or Ra, Rb and Rc together with the carbon atom to which they are attached form a tricyclic ring (for example adamantyl); or Ra and Rb are each independently (C,-C6) alkyl, (C2-C6) alkenyl, (C2- C6) alkynyl, phenyl (C,-C6) alkyl, or a group as defined for Rc below other than hydrogen, or Ra and Rb together with the carbon atom to which they are attached form a cycloalkyl or heterocyclic ring, and Rc is hydrogen,-OH,-SH, halogen,-CN,-CO2H, (C,-C4) perfluoroalkyl,- CH20H,-C02 (C,-C6) alkyl,-O (C,-C6) alkyl,-O (C2-C6) alkenyl,-S (C,-<BR> C6) alkyl,-SO (C,-C6) alkyl,-S02 (C,-C6) alkyl,-S (C2-C6) alkenyl,-SO (C2- C6) alkenyl,-S02 (C2-C6) alkenyl or a group-Q-W wherein Q represents a bond or-0-,-S-,-SO-or-S02-and W represents a phenyl, phenylalkyl, (C3-C8) cycloalkyl, (C3-C8) cycloalkylalkyl, (C4-<BR> C8)cycloalkenyl, (C4-C8) cycloalkenylalkyl, heteroaryl or heteroarylalkyl group, which group W may optionally be substituted by one or more substituents independently selected from, hydroxyl, halogen,-CN,- CO2H,-C02 (C,-C6) alkyl,-CONH2,-CONH (C,-C6) alkyl,-CONH (C,- C6alkyl) 2,-CHO,-CH20H, (C,-C4) perfluoroalkyl,-O (C,-C6) alkyl,-S (C,-<BR> C6) alkyl,-SO (C,-C6) alkyl,-S02 (C,-C6) alkyl,-N02,-NH2,-NH (C,- C6) alkyl,-N ((C,-C6) alkyl) 2,-NHCO (C,-C6) alkyl, (C,-C6) alkyl, (C2- C6)alkenyl, (C2-C6) alkynyl, (C3-C8) cycloalkyl, (C4-C8) cycloalkenyl, phenyl or benzyl. <BR> <BR> <P>Examples of particular R3 groups include benzyl, phenyl, cyclohexylmethyl, pyridin-<BR> 3-ylmethyl, tert-butoxymethyl, iso-butyl, sec-butyl, tert-butyl, 1-benzylthio-1- methylethyl, 1-methylthio-1-methylethyl, and 1-mercapto-1-methylethyl. <BR> <BR> <P>Presently preferred R3 groups include phenyl, benzyl, tert-butoxymethyl and iso-<BR> butyl.

The R4 Examples of particular ester and thioester groups R4 groups include those of<BR> - (C=O) OR9,- (C=O) SR9,- (C=S) SR9, and- (C=S) OR9 wherein Rg is (C,-C6) alkyl, (C2- C6)alkenyl, cycloalkyl, cycloalkyl (C,-C6) alkyl-, phenyl, heterocyclyl, phenyl (C,- (C1-C6)alkoxy(C1-C6)alkyl-,(C1-C6)alkoxy(C1-C6)alkyl-,hetero cyclyl(C1-C6)alkyl-, C6) alkoxy(C1-C6)alkyl-, any of which may be substituted on a ring or non-ring carbon atom or on a ring heteroatom, if present. Examples of such Rg groups include methyl, ethyl, n-and iso-propyl, n-, sec-and tert-butyl, 1-ethyl-prop-1-yl, 1-methyl- prop-1-yl, 1-methyl-but-1-yl, cyclopentyl, cyclohexyl, allyl, phenyl, benzyl, 2-, 3-and 4-pyridylmethyl,N-methylpiperidin-4-yl, 1-methylcyclopent-1yl, adamantyl, tetrahydrofuran-3-yl and methoxyethyl.

Presently preferred are compounds of formula (I) wherein R4 is a carboxylate ester of formula- (C=O) OR9, wherein Rg is benzyl, cyclopentyl, isopropyl or tert-butyl.

The group_ Presently preferred R groups are hydrogen and methyl.

Compounds used according to the present invention may be prepared by the methods described in our published international patent application No WO 98/11063. Specific examples of compounds which may be used are those of the following examples 1-50. Examples 1-42 are compounds disclosed in WO 98/11063.

A compound presently preferred for its potency as an intracellular LTA4 inhibitor is that of Example 19, namely 2S- (3S-hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid cyclopentyl ester, and pharmaceutically acceptable salts, hydrates and esters thereof.

Example 1 (Example 1 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid methyl ester.

Example 2 (Example 2 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid ethyl ester.

Example 3 (Example 3 of WO 98/11063) 2S- roxyCarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenyipropioni c acid isopropyl ester.

Example 4 (Example 5 of WO 98/11063) <BR> <BR> 3R-(2-Phenyl-1S-methylcarboxy-ethylcarbamoyl)-2S, 5-dimethylhexanohydroxamic acid Example 5 (Example 6 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenyl- propionic acid tert-butyl ester Example 6 (Example 7 of WO 98/11063) <BR> <BR> 2S- (2R-Hydroxycarbamoylmethyl-4-methyl-pentanoylamino)-3-phenyl -propionic acid isopropyl ester Example 7 (Example 8 of WO 98/11063) 2S- [2R- (S-Hydroxy-hydroxycarbamoyl-methyl)-4-methyl-pentanoylamine] -3-phenyl- propionic acid isopropyl ester.

Example 8 (Example 9 of WO 98/11063) <BR> <BR> 2S- [2R- (1 S-Hydroxycarbamoyl-ethyl)-4-methyl-pentanoylamino]-3-phenyl- propionic acid isopropyl ester.

Example 9 (Example 10 of WO 98/11063) 2S- (2R-Hydroxycarbamoylmethyl-octanoylamino)-3-phenyl-propionic acid isopropyl ester.

Example 10 (Example 11 of WO 98/11063) 2S- [2R- (S-Hydroxy-hydroxycarbamoyl-methyl)-4-methyl-pentanoylamino] -3-phenyl- propionic acid cyclopentyl ester.

Example 11 (Example 12 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3S-methyl -pentanoic acid cyclopentyl ester.

Example 12 (Example 13 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid 2- methoxy-ethyl ester.

Example 13 (Example 1 of WO 98/11063) 2S- [2R- (1 S-Hydroxycarbamoyl-ethyl)-4-methyl-pentanoylamino]-3-phenyl- propionic acid 2-methoxy-ethyl ester.

Example 14 (Example 15 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hexanoylamino)-3, 3-dimethyl-butyric acid 2- methoxy-ethyl ester.

Example 15 (Example 1 of WO 98/11063) <BR> <BR> 2S- [2R- (S-Hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino] -3-phenyl- propionic acid isopropyl ester.

Example 16 (Example 17 of WO 98/11063) <BR> <BR> 2S- {2R- [1 S-Hydroxycarbamoyl-2- (thiophen-2-ylsulphanyl)-ethyl]-4-methyl- pentanoylamino}-3-phenyl-propionic acid isopropyl ester.

Example 17 (Example 18 of WO 98/11063) <BR> <BR> 2S- [2-R- (1 S-Hydroxycarbamoyl-ethyl)-4-methyl-pentanoylamino]-3, 3-dimethyl- butyric acid 2-methoxy-ethyl ester.

Example 18 (Example 19 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)- 3, 3-dimethyl-butyric acid 2-methoxy-ethyl ester.

Example 19 (Example 20 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid cyclopentyl ester.

Example 20 (Example 21 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hexanoylamino)-3-phenylprop ionic acid isopropyl ester.

Example 21 (Example 22 of WO 98/11063) 2S-(3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)- 3, 3-dimethyl-butyric acid isopropyl ester.

Example 22 (Example 23 of WO 98/11063) <BR> <BR> 2R- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid isopropyl ester.

Example 23 (Example 24 of WO 98/11063) <BR> <BR> <BR> 2S- [2R- (S-Hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino] -3,3- dimethyl-butyric acid isopropyl ester.

Example 24 (Example 25 of WO 98/11063) <BR> <BR> 2S- { (3S-Hydroxycarbamoyi-2R-isobutyl-hex-5-enoyl)-methyl-amino)- 3- phenylpropionic acid isopropyl ester.

Example 25 (Example 26 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid benzyl ester.

Example 26 (Example 27 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-4-methyl- pentanoic acid cyclopentyl ester.

Example 27 (Example 28 of WO 98/11063) 3-Cyclohexyl-2S- (3S-hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-propionic acid cyclopentyl ester.

Example 28 (Example 29 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid 1- methyl-piperidin-4-yl ester.

Example 29 (Example 30 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid 1- ethyl-propyl ester.

Example 30 (Example 31 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid 1S-methyl-butyl ester.

Example 31 (Example 32 of WO 98/11063) <BR> <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid cyclohexyl ester.

Example 32 (Example 1 of WO 98/11063) <BR> <BR> 2S- {2R- [1 S-Hydroxycarbamoyl-2- (thiophen-2-ylsulphanyl)-ethyl]-4-methyl- pentanoylamino}-3,3-dimethyl-butyric acid isopropyl ester.

Example 33 (Example 34 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid 1 R-methyl-butyl ester.

Example 34 (Example 35 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3-phenylp ropionic acid tetrahydro-furan-3 (R, S)-yl ester.

Example 35 (Example 36 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-3, 3-dimethyl-butyric acid cyclopentyl ester.

Example 36 (Example 37 of WO 98/11063) <BR> <BR> 2S-[2R-(1 S-Cyclopentyl-hydroxycarbamoyl-methyl)-4-methyl-pentanoylami no]-3- phenyl-propionic acid cyclopentyl ester.

Example 37 (Example 38 of WO 98/11063) 2S- [2R- (l S-Hydroxy-hydroxycarbamoyl-methyl)-pent-4-ynoylamino]-3- phenylpropionic acid cyclopentyl ester.

Example 38 (Example 39 of WO 98/11063) 2S-R-isobutyl-hex-5-enoylamino)-3-pyridin-3-yl-propionic acid cyclopentyl ester.

Example 39 (Example 40 of WO 98/11063) <BR> <BR> 3-tert-Butoxy-2S- (3S-hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-propionic acid cyclopentyl ester.

Example 40 (Example 41 of WO 98/11063) <BR> <BR> 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-2-phenyle thanoic acid cyclopentyl ester.

Example 41 (Example 42 of WO 98/11063) <BR> <BR> 2S- [5- (2-Chlorophenyl)-2R- (1 S-hydroxy-hydroxycarbamoyl-methyl)-pent-4- ynoylamino]-3-phenylpropionic acid cyclopentyl ester.

Example 42 (Example 43 of WO 98/11063) 2S- (3S-Hydroxycarbamoyl-2R-isobutyl-6-phenyl-hex-5-enoylamino)- 3-phenyl- propionic acid cyclopentyl ester.

Example 43 <BR> <BR> <BR> 2- [2R- (S-Hydroxy-hydroxycarbamoyl-methyl)-4-methyl-pentanoylamine] -2-phenyl- ethanoic acid cyclopentyl ester Prepared using procedures similar to those described in example 8 of WO 98/11063, using phenylglycine cyclopentyl ester.

Diastereoisomer A 'H-NMR; 8 (MeOD), 7.4-7.29 (5H, m), 5.43 (1H, s), 5.2-5.14 (1H, m), 4.02 (1H, d, J=6.9Hz), 2.94-2.85 (1H, m), 1.91-1.34 (10H, bm), 1.25-1.14 (1H, m) and 0.86 (6H, dd, J=6.5,11.5Hz).

'3C-NMR; b (MeOD), 175.6,171.8,171.4,137.8,129.8,129.4,128.6,80.0,73.2, 58.5,49.2,39.1,33.3,33.3,26.8,24.5,24.4,23.7 and 22.1.

Diastereoisomer B <BR> 'H-NMR; 6 (MeOD), 7.33-7.19 (5H, m), 5.3 (1H, s), 5.11-5.06 (1H, m), 3.81 (1H, d, J=7.3Hz), 2.83-2.74 (1H, m), 1.83-1.45 (10H, bm), 1.12-1.03 (1H, m) and 0.88-0.81 (6H, dd, 8 (MeOD), 175.8,171.8,171.5,137.3, 0 and 22.2.

Example 44 2- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-2-phenyle thanoic acid isopropyl ester Prepared using methods similar to those described in example 41 of application WO 98/11063 using phenylglycine isopropyl ester.

Diastereoisomer A 'H-NMR; 8 (MeOD), 7.34-7.24 (5H, m), 5.59-5.42 (1H, m), 5.36 (1 H, s), 5.02-4.77 (3H, m), 2.63-2.53 (1H, m), 2.17-2.02 (2H, m), 1.89-1.78 (1H, m), 1.63-1.45 (2H, m), 1.18 (3H, d, J=6.3Hz), 1.05 (3H, d, J=6.2Hz), 1.00-0.93 (1H, m), 0.88 (3H, d, J=6.5Hz) and 0.81 (3H, d, 6 (MeOD), 176.2,172.4,171.3, 137.6,136.0,129.9,129.6,129.0,117.4,70.5,58.7,47.4,41.5,36.0 ,26.7,24.5, 21.9,21.7 and 21.7.

Diastereoisomer B 'H-NMR; 8 (MeOD), 7.4-7.34 (5H, m), 5.77-5.61 (1H, m), 5.42 (1H, s), 5.1-4.98 (3H, m), 2.7-2.6 (1H, m), 2.44-2.17 (3H, m), 1.61-1.5 (1H, m), 1.42-1.29 (1H, m), 1.25 (3H, d, J=6.3Hz), 1.13 (3H, d, J=6.2Hz), 1.09-1.00 (1H, m) and 0.81 (6H, d, b (MeOD), 176.4,172.5,171.5,137.2,136.4,129.9,129.6, 129.0,117.5,70.5,58.8,48.4,47.4,41.3,36.0,27.1,24.3,21.9,21. 8 and 21.6.

Example 45 2- [2R- (S-Hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino] -3- phenylethanoic acid cyclopentyl ester Prepared using methods similar to those described in example 16 of application WO 98/11063, using phenylglycine cyclopentyl ester.

Diastereoisomer A 'H-NMR; 8 (MeOD), 8.83 (1H, d, J=6.6Hz), 7.48-7.29 (5H, m), 5.44-5.42 (1H, m), 5.20-5.16 (1H, m), 3.53 (1H, d, J=9.7Hz), 3.17 (3H, s), 2.89-2.79 (1H, m), 1.90-1.54 (10H, bm), 1.06-0.99 (1H, m), 0.95 (3H, d, J=6.5Hz) and 0.90 (3H, d, J=6.4Hz).

13C-NMR; 8 (MeOD), 175.3,171.6,169.4,137.5,129.7,129.4,128.7,83.1,79.9, 58.7,58.1,48.5,38.4,33.4,33.3,26.7,24.6,24.5,24.3 and 21.8.

Diastereoisomer B 'H-NMR; 8 (MeOD), 7.39-7.30 (5H, m), 5.45 (1H, s), 5.21-5.15 (1H, m), 3.59 (1H, d, J=9.4Hz), 3.29 (3H, s), 2.89-2.79 (1 H, m), 1.93-1.49 (9H, bm), 1.42-1.21 (1 H, m), 1.01 (1 H, ddd, J=3.7,9.9,13.3Hz), 0.83 (3H, d, J=6.5Hz) and 0.79 (3H, d, J=6.6Hz).

13C-NMR; 8 (MeOD), 128.7,83.0,79.8, 58.5,58.3,48.6,38.5,33.3,27.8,24.5,24.4,24.1 and 21.7.

Example 46 2-(3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-2- (4- methoxyphenyl) ethanoic acid cyclopentyl ester Prepared using methods similar to those described in example 41 of application WO 98/11063, using 4-methoxyphenylglycine cyclopentyl ester.

Diastereoisomer A 'H-NMR; 5 (MeOD), 8.94 (1 H, d, J=6.4Hz), 7.32 (2H, d, J=8.7Hz), 6.93 (2H, d, J=8.7Hz), 5.67-5.50 (1H, m), 5.36-5.33 (1H, m), 5.20-5.14 (1H, m), 4.93-4.87 (2H, m), 3.79 (3H, s), 2.68-2.59 (1 H, m), 2.24-2.09 (2H, m), 1.97-1.55 (11 H, bm), 1.11-1.00 (1 H, m), 0.95 (3H, d, J=6.5Hz) and 0.88 (3H, d, 8 (MeOD), 176.2,172.4,171.9,161.4,136.0,130.2,129.4,117.4,115.2,79.7,5 8.2, 55.8,48.3,47.3,41.5,36.0,33.4,33.3,26.7,24.6,24.5 and 21.7.

Diastereoisomer B 'H-NMR; 5 (MeOD), 8.96 (1H, d, J=6.7Hz), 7.29 (2H, d, J=8.7Hz), 6.93 (2H, d, J=8.7Hz), 5.77-5. 61 (1H, m), 5.32 (1H, s), 5.20-5.15 (1H, m), 5.09-4.97 (2H, m), 3.80 (3H, s), 2.64 (1H, dt, J=3.3,11.4,13.5Hz), 2.43-2.16 (3H, m), 1.91-1.49 (9H, bm), 1.42-1.29 (1H, m), 1.05 (1H, ddd, J=3.3,10.1,13.2Hz) and 0.81 (6H, d, 5 (MeOD), 176.3,172.5,172.0,161.4,136.4,130.2,129.0, 24.5,24.3 and 21.6.

Example 47 2- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-2- (thien-2-yl) ethanoic acid cyclopentyl ester Prepared using methods similar to those described in example 41 of application WO 98/11063, using thien-2-ylglycine cyclopentyl ester.

Diastereoisomer A 'H-NMR; 8 (MeOD), 7.41 (1 H, dd, J=5.1,1.2Hz), 7.12 (1H, d, J=3.5Hz), 7.01 (1H, dd, J=5.1,3.5Hz), 5.72 (1H, s), 5.69-5.52 (1H, m), 5.26-5.18 (1H, m), 5.00-4.89 (2H, m), 2.70-2.59 (1H, m), 2.28-2.13 (2H, m), 2.09-1.50 (11H, m), 1.05 (1H, ddd, J=13.8,11.0,2.9Hz), 0.93 (3H, d, J=6.4Hz) and 0.87 (3H, d, J=6. 5Hz). 13C-NMR ; 8 (MeOD), 176.5,172.7,171.1,139.5,136.4,128.4,128.3,127.7,117.9,80.7,5 4.1, 48.7,47.7,41.9,36.5,33.8,33.7,27.2,25.1,25.0,24.9, and 22.1.

Diastereoisomer B 'H-NMR; 8 (MeOD), 7.42 (1H, dd, J=5.0,0.7Hz), 7.10 (1H, d, J=3.6Hz), 7.01 (1H, dd, J=5.0,3.6Hz), 5.79-5.59 (2H, m), 5.28-5.19 (1H, m), 5.10-4.94 (2H, m), 2.71-2.59 (1H, m), 2.36-2.16 (3H, m), 1.97-1.34 (10H, m), 1.13-1.00 (1H, m), 0.86 (3H, d, J=6.2Hz) and 0.84 (3H, d, 8 (MeOD), 176.7,172.8, 171.2,139.3,136.7,128.3,128.2,127.6,117.9,80.7,54.2,48.8,47. 8,41.7,36.4, 33.8,27.5,25.1,25.0,24.8 and 22.1.

Example 48 2- (3S-Hydroxycarbamoyl-2R-isobutyl-hex-5-enoylamino)-2- (thien-3-yl) ethanoic acid cyclopentyl ester Prepared using methods similar to those described in example 41 of application WO 98/11063, using thien-3-ylglycine cyclopentyl ester.

Diastereoisomer A 'H-NMR; 8 (MeOD), 7.48-7.42 (2H, m), 7.13 (1H, dd, J=4.2,2.0Hz), 5.69-5.52 (2H, m), 5.21-5.16 (1H, m), 4.98-4.90 (2H, m), 2.71-2.59 (1H, m), 2.28-2.11 (2H, m), 2.00-1.50 (11 H, m), 1.12-0.98 (1 H, m), 0.94 (3H, d, J=6.4Hz) and 0.88 (3H, d, 8 (MeOD), 176.6,172.8,171.8,137.8,136.4,128.3,128.0, 125.2,117.9,80.3,54.6,41.9,36.5,33.8,33.8,27.1,25.0,24.9 and 22.1.

Diastereoisomer B 'H-NMR; 8 (MeOD), 7.45 (1H, dd, J=4.9,3. 0Hz), 7.43-7.40 (1H, m), 7.12 (1H, dd, J=5.0,1.3Hz), 5.68 (1H, ddt, J=17.0,10.1,6.8Hz), 5.53 (1H, s), 5.23-5.17 (1H, m), 5.10-4.96 (2H, m), 2.70-2.60 (1H, m), 2.41-2.16 (3H, m), 1.94-1.49 (9H, m), 1.44-1.29 (1H, m), 1.05 (1H, ddd, J=12.9,10.3,3.3Hz), 0.84 (3H, d, J=6.5Hz) and 0.83 (3H, d, J=6.5Hz).

Example 49 <BR> <BR> 2S- [2R- (S-Hydroxy-hydroxycarbamoyl-methyl)-3-phenyl-propanoylamine] -2-phenyl- ethanoic acid cyclopentyl ester. This compound was prepared using the method of example 11 of patent application WO 98/11063 and intermediates similar to those described in patent application W095/19956.'H-NMR; 8 (MeOD), 7.39-7.15 (10H, m), 5.32 (1H, s), 5,15-5.06 (1H, m), 4.05 (1H, d, J=5.7Hz), 3.19-3.10 (1H, m), 3.02-2.81 (2H, m) and 1.89-1.40 (8H, m). 13C-NMR; 8 (MeOD), 175.4,172.1,171.8,140.2,137.9,130.6,130.1,129.9, 129.7,128.9,80.4,72.7,58.6,52.4,36.5,33.7,24.9 and 24.8.

Example 50 2S-(3S-Hydroxycarbamoyl-2R-cyclopentylmethyl-hex-5-enoylamin o)-2-phenyl- ethanoic acid cyclopentyl ester.

This compound was prepared using the method described for example 1 of patent application WO 98/11063 and intermediates similar to those described in patent application WO 94/21625.'H-NMR; â (MeOD), 9.02 (1H, m), 7.40 (5H, m), 5.60 (1H, m), 5.45 (1H, m), 5,17 (1H, m), 4.90 (2H, m), 2.61 (1H, m), 2.20 (2H, m), 2.05-1.40 (17H, m) and 1.10 (3H, m).

Biological Example A LTA4-hydolase was prepared as a crude fraction from rat lung tissue. The sodium salt of LTA4 was incubated with the enzyme and test compounds at 10µM for 1 minute at 37°C. The reaction was terminated by the addition of ice-cold methanol.

Formation of LTB4 was assessed by radioimmunoassay. Results are expressed as a percentage inhibition of LTA4 hydrolase activity.

The results obtained are expressed in the following table CompoundCompound%Inhibition at 10µM Example 40 75 Example 19 78 For comparison the known LTA4-hydrolase inhibitor kelatorphan inhibits activity by 80% at 10pM.

BiologicalExample B Inhibition of Leukotriene Synthesis by Rat Basophilic Leukaemia Cells The rat basophilic leukaemia cell line RBL-1 was obtained from ATCC or ECACC and cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% foetal bovine serum, non-essential amino acids, sodium pyruvate, penicillin, streptomycin and 2mM glutamine, at 37°C in an atmosphere of 5% C02 in air, as recommended by the culture collection.

RBL-1 cells were harvested during log growth, washed and resuspended in Hanks Balance Salt Solution, without calcium chloride and magnesium chloride, supplemented with 10% foetal bovine serum and penicillin, streptomycin, and 2mM glutamine and adjusted to a final cell concentration of 1.25X105 cells/ml. Cells incubated in the presence of the appropriate concentration of inhibitor or vehicle for 4.75 hours at 37°C. Cells then transferred to ice for 15 minutes. Cells washed by centrifugation and resuspension in pre-chilled Phosphate Buffered Saline, with calcium chloride and magnesium chloride, supplemented with the appropriate concentration of test sample. After the PBS wash, cells resuspended at a final cell concentration of equalivent to 2.35X106 cell/ml in PBS/sample buffer. Cells transferred to a microfuge tube on ice prior to ionophore stimulation.

Treated cells then exposed to 10µM A23187 for 15 minutes at 37°C. Cells transferred to ice, thereby stopping the reaction. Cell free supernatant harvested by centrifugation. The levels of leukotriene B4 then determined in the cell free supernatant using the Leukotriene B4 [3H] assay system from Amersham Pharmacia Biotech.

Using this methodology the IC50 value for the compound of example 19 was estimated as 2nM and for Kelatorphan as 350nM.

Biological Example C Rat Adjuvant Arthritis Model Adjuvant arthritis was induced in male Lewis rats on Day 0, using a suspension of mycobacterium butyricum in mineral oil, inoculated subcutaneously, into the base of the tail. The volume of the hind paws was measured regularly to assess the time course of disease progression. On Day 10 animals were randomised into treatment groups, to ensure that each group had a similar mean hind paw volume at the start of treatment. Nine animals were allocated to each group. Animals received their first treatment on Day 10, either vehicle (2% DMSO in PBS/Tween (0.01 % v/v)) or test compound, formulated as a suspension in the vehicle. Treatment was administered as an intraperitoneal bolus injection, once daily, for the duration of the study. The study was ended on Day 21. The percent increase in mean paw volume from Day 10 to Day 21 was calculated for each animal and the compound treated groups compared to the vehicle treated control group.

The compound of example 19, administered at 30mg/kg and 100mg/kg i. p., inhibited paw swelling by 60% and 77% respectively. This inhibition was statistically significant (P<0.05) at both doses.