WO1997035859A1

WO1997035859A1 - Compounds with a sulfamoyl group and pharmaceutical compositions containing them

Info

Publication number: WO1997035859A1
Application number: PCT/EP1997/001556
Authority: WO
Inventors: Desmond John Best; John Stephen Elder; Neal Frederick Osborne
Original assignee: Smithkline Beecham Plc
Priority date: 1996-03-25
Filing date: 1997-03-21
Publication date: 1997-10-02
Also published as: GB9606208D0

Abstract

Compounds of formula (I) are selective inhibitors of the bacterial enzyme iso-leucyl t-RNA synthetase and therefore of potential therapeutic use as antibacterial agents.

Description

COMPOUNDS WITH A SULFAMOYL GROUP AND PHARMACEUTICAL COMPOSITIONS CON¬ TAINING THEM

The present invention relates to novel anti-bacterial compounds, pharmaceutical compositions containing such compounds, processes for the preparation thereof and the use thereof in therapy.

Anti-bacterial agents operate via a series of different mechanisms which result in a bacteriocidal and/or bacteriostatic effect. One such mechanism which has been taken advantage of is selective inhibition of a bacterial aminoacyl t-RNA synthetase. t-RNA synthetases have a primary role in protein synthesis according to the following scheme:

Enzyme +ATP + AA <=> Enzyme.AA-AMP + PPi

Enzyme.AA-AMP + t-RNA <= Enzyme + AMP + AA-t-RNA

in which AA is an amino acid.

Inhibition of this process leads to a reduction in the levels of charged t-RNA and this triggers a cascade of responses known as the stringent response, the result of which is the induction of a state of dormancy in the organism.

Mupirocin (orginally known as pseudomonic acid A), the compound of formula (A):

(A) is an antibacterial agent which inhibits protein synthesis through reversible selective inhibition of isoleucyl t-RNA synthetase by preventing formation of an De.AMP intermediate, from both Gram -positive and Gram-negative bacteria. It shows excellent selectivity for prokaryote over eukaryote isoleucyl t-RNA synthetases and also excellent selectivity for the isoleucyl t-RNA synthetase over the other nineteen bacterial aminoacyl t-RNA synthetases. The compound is marketed as a topical antibacterial product under the trade name Bactroban by SmithKline Beecham; ester lability precluding systemic administration. The relative instability of mupirocin has limited the therapeutic use thereof to topical applications. Much effort has therefore been devoted to developing derivatives of mupirocin which retain the desirable antibacterial properties thereof but which are sufficiently stable to allow for systemic use. Attention has focussed on replacing the α,β- unsaturated ester moiety with a variety of other structural units which may be more resistant to enzymatic hydrolysis, for instance: α-methyl-α,β-unsaturated esters (EP 0 090 603- A); α,β-unsaturated thiol esters (EP 0 002 371 -A); α,β-unsaturated amides (EP 0001 914-A); α,β-unsaturated ketones (EP 0 029665-A, WO 91/09855, WO 92/02518, J Med Chem, 1989, 32, 151); β-hydroxy ketones (WO 93/06118), cyclic ketones (WO 94/02478) and 5- and 6-membered heterocyclic rings (EP 0087 953-A, EP 0 123 378- A, EP 0 352 909- A, EP 0 399 645-A and WO 91/09856). In addition, related compounds have been described in which the C1-C3 moiety is replaced by a heterocyclic moiety (WO 95/16686, SmithKline Beecham pic)

More recently, there have been reports of compounds produced by marine microrganisms which are closely related to mupirocin and which have antibacterial activity. The compound of formula (D):

(D) in which R is hydrogen or hydroxyl is produced by an Alteromonas species associated with a marine sponge (Stierle D B and Stierle A A, 200th National Meeting of ACS, Washington DC, Aug 26-31, 1990 and Experientia, 1992, 8, 1165). The stereochemistry of the C-4 hydroxyl was inferred to be β-, based on spectroscopic studies.

In addition, further compounds, named thiomarinol and thiomarinol C are produced by the microorganism Alteromonas rava. These have the general formula (E):

(E) in which R is hydroxyl (thiomarinol) or hydrogen (thiomarinol C) [EP 0512 824-A1, Sankyo Co Ltd and Shiozawa et al, J Antibiotics, 1993(12), 46, 1834-1842 (thiomarinol) and EP 0 595458-A1, Sankyo Co Ltd (thiomarinol C)]. The thiomarinols are said to possess good anti- bacterial activity against both Gram-positive and Gram-negative organisms, as well as being active against mycoplasma. The amine forming the terminal amide is a pyrrothine, in particular a holothin. The acetamides thereof include the known anti-bacterial compounds thiolutin (Merck Index, 11th edn, 1989, 1471) and holomycin (Merck Index, 11th edn, 1989, 747). Thiolutin also has anti-fungal activity.

Semi-synthetic compounds related to thiomarinol in which the linkage between the monic acid and pyrrothine moieties is varied have recently been described (PCT applications, publication nos WO 94/26750; WO 94/28001 and WO 95/05384, SmithKline Beecham pic).

More recently, further modifications at the 5-position of the tetrahydropyranyl ring have been investigated, for instance International application PCT/EP96/033441 (SmithKline Beecham pic) describes compounds of the formula (A):

(A) in which:

R^a is an pharmaceutically acceptable ester-forming radical;

R^b is an optionally substituted (Cj.gjalkyl or (Ci.gtølkylamino group;

Z is O or H,H; and n is 1 or 2.

These sulfamoyl derivatives are selective inhibitors of isoleucyl t-RNA synthetase.

It has now been found that the α,β-unsaturated ester moiety may be replaced by a variety of other moieties without compromising activity against bacterial isoleucyl t-RNA synthetase.

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

(I⁾ in which:

R¹ is selected from: (a) C(Me)=CHCOB¹ in which:

B¹ is aryl, preferably phenyl, (Cι .ι_υ)alkyl, (C2-io)alkenyl, (C2-io)alkynyl, (C3_7)cycloalkyl, aryl(Cι.4)alkyl or heterocyclyl, preferably heteroaryl, each of which may be optionally substituted;

(b) C(Me)=CHCONHB² in which: B² is optionally substituted (C _6)alkyl or aryl(C i galkyl ;

(c)

in which:

B^ is aryl, preferably phenyl, or a 5- or 6- membered heteroaryl ring having from 1 to 4 heteroatoms, preferably 1 to 3, most preferably 1 or 2, each selected from oxygen, sulphur or nitrogen and optionally substituted by (Cι_ιo)alkyl, (C2-io)alkenyl, (C2-io) l^kyⁿyL (C3_7)cycloalkyl, aryl(Cι_4)alkyl, aryl or heterocyclyl,

( )

(which corresponds to C(OH)=CHCOB⁴), in which B⁴ is an optionally substituted aryl or heteroaryl group; (e)

in which Q denotes the residue of an optionally substituted aryl or heteroaryl ring; or (e) a 5-membered heteroaryl ring:

hereinafter referred to as HET, in which X and X2 is each independently selected from carbon, nitrogen, oxygen or sulphur, X3 is selected from carbon or nitrogen, optionally substituted by an aryl or a heteroaryl ring, X4 is selected from nitrogen, oxygen or sulphur and X5 is carbon, or X\, X , X4 and X5 is each nitrogen and X3 is carbon; R² is an optionally substituted (C'.^alkyl group; and n is 1 or 2.

Compounds of formula (I) are selective inhibitors of bacterial isoleucyl t-RNA synthetase and therefore potentially of use as anti-bacterial agents.

Suitable examples of heteroaryl groups for B * include: furan, thiophene, pyrrole, benzofuran, benzothiophene, indole, oxazole, isoxazole, thiazole, isothiazole, pyrazole, benzimidazole, oxadiazole, thiadiazole, triazole, tetrazole, thiatriazole, pyridine, quinoline, isoquinoline, pyrazine, pyrimidine, pyridazine and triazine; preferably thiophene, furan, pyrrole, thiazole, isothiazole, pyridine, pyrimidine, and quinoline, preferably:

Suitable heteroaryl groups for B^ include furan, thiophene, pyrrole, diazole, oxazole, thiazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole and tetrazole; preferably:

more preferably:

Suitably such heteroaryl groups may be substituted by an optionally substituted phenyl group or a heteroaryl group selected from :

Representative values for B^ include

In B⁴, suitable heteroaryl groups include pyrimidine, thiazole, oxazole and pyridine and suitable aryl groups include phenyl.

Suitably the aryl ring of which Q forms a residue is benzene or naphthalene, preferably benzene, which may be unsubstituted or substituted by up to three, suitably up to one further substituent. Suitably the heteroaryl ring of which Q forms a residue includes both single and fused rings, with each ring suitably comprising up to four heteroatoms each selected from oxygen, nitrogen and sulphur, which rings may be unsubstituted or substituted by, for example, up to two further substituents. Each heteroaryl ring may have from 4 to 7, preferably 5 or 6, ring atoms. A fused heteroaryl ring may include an aryl ring and need include only one heteroaryl ring. Suitable fused heteroaryl rings include bicyclic systems. Preferably the heteroaryl ring of which Q forms a residue is a monocyclic heteroaryl ring, for instance pyridine or furan.

Representative examples of the moiety:

include

in each of which the aryl or heteroaryl ring may be optionally substituted. It will be appreciated that in these instances, the aryl ring of which Q forms a residue is benzene and the heteroaryl ring of which Q forms a residue is furan or pyridine.

Representative examples of the heteroaryl group HET include oxazol-5-yl, thiazol-4-yl, isoxazol-3-yl, isoxazol-5-yl, l,2,4-oxadiazol-5-yI, l,3,4-oxadiazol-2-yl, l,2,3-triazol-4- yl, l,2,4-triazol-3-yl, tetrazol-2-yl and tetrazol-5-yl. Suitable substiuents include optionally substituted phenyl, pyridyl, furanyl and benzofuranyl. Preferably, HET is an oxazol-5-yl ring.

Suitably, the alkyl group in R² may be substituted by one or two substituents selected from, for example, amino, (Cι _6)acylamino, [(α-amino)acyl]amino, (Cj.gjalkylamino, aryl(Cι_4)alkylamino, ureido, halogen, hydroxyl, (Cι_6)acyloxy and (Cj^alkylidene, carboxy, carbamoyl, aryl, heterocyclyl, hydroxy, thio, (Cι_6)alkylthio and guanidine

Suitably, R² is a group of the formula:

R³CH(NHR⁴) in which: R³ is hydrogen or a (Cι_5)alkyl group optionally substituted with a substituent selected from hydroxyl, carboxy, carbamoyl, amino, aryl, heterocyclyl, hydroxy, thio, (C ι _6)alkylthio and guanidino; and

R⁴ is H, (Cι_6)acyl, (Cj _6)alkyl, aryl(Cι _4)alkyl or the residue of an α-amino acid, suitably a naturally occurring α-amino acid.

Representative examples of the group R² include 1-methylprop-l-yl, l-methyl-2- hydroxyprop- 1 -yl, 1 -amino-2-methylbut- 1 -yl, 1 -(N-methyl)amino-2-methylbut- 1 -yl, 1 -(N-benzyl)-amino-2-methylbut- 1 -yl, 2-methylbut- 1 -yl, 1 -acetoxy-2-methylbut- 1 -yl, l-hydroxy-2-methylbut-l-yl, 2-methyl-l-ureidobut-l-yl, 3-hydroxybut-2-yl and 1-methylethyl amino.

Suitably, in compounds of formula (I), the radical R²CO is derived from isoleucine. Accordingly, it will be readily appreciated that within compounds of formula (I), there is a subclass of compounds which may be represented by the formula (IA):

(IA) in which: R⁴ is H, (Cj.6)acyl, (Cι _6>alkyl, aryl(Cι_4)alkyl, carbamoyl, or the an α-amino acid, suitably a naturally occurring α-amino acid; and n and R* are as hereinbefore defined.

It will be further readily appreciated by those skilled in the art that compounds of the formula (1 ) in which the group R² contains a basic amino function are zwitterionic and may therefore be more accurately represented by the formula (IB):

(IB) in which R*, R³ and n are as hereinbefore defined and R⁴ is as hereinbefore defined, other than (Cι_6)acyl.

Suitably, in compounds of formula (I), n is 1.

When used herein, the term 'alkyl' and similar terms such as 'alkoxy' refers to, unless otherwise indicated, all straight and branched chainisomers. Representative examples thereof include, for instance, methyl, ethyl, n-propyl, iyo-propyl, π-butyl, sec-butyl, iso¬ butyl, t-butyl, n- pentyl and /i-hexyl. Alkyl groups may be optionally substituted with one or two substituents selected from halogen, cyano, azido, nitro, carboxy, (Cι_6)alkoxycarbonyl, carbamoyl, mono- or di-(Ci_6)^aUcyl^carDam°y sulpho, sulphamoyl, mono- or di-(Cι _6)alkylsulphamoyl, amino, mono- or di-(Cι .6)alkylamino, acylamino, [(α-amino)acyl]amino, ureido, (Cμgjalkoxycarbonylamino, 2,2,2-trichloroethoxycarbonylamino, aryl, heterocyclyl, hydroxy, (Cι_6)alkoxy, acyloxy, oxo, acyl, 2-thienoyl, thio, (Cι _6)alkylthio, (Cι _6)alkylsulphinyl, (Cι _6)alkylsulphonyl, hydroxyimino, (Cι_6)alkoxyimino, hydrazino, hydrazono, benzohydroximoyl, guanidino, amidino and iminoalkylamino.

When used herein, the term 'aryl' includes, unless otherwise defined, phenyl and napthyl optionally substituted with up to five substituents selected from halogen, (Cι_6)» ( - 6)alkoxy, halo(Cι_6)alkyl, hydroxy, amino, carboxy, (Cι_6)aIkoxycarbonyl or (Cι _6)^al^|coχy^carbonyl(Cι_6)alkyl groups.

When used herein, the term 'heterocyclyl' includes aromatic and non-aromatic single or fused rings comprising up to four heteroatoms in the ring selected from oxygen, nitrogen and sulphur and optionally substituted with up to three substituents. Suitably the heterocyclic ring comprises from 4 to 7, preferably 5 to 6, ring atoms. A fused heterocyclic ring system may include carbocyclic rings and need only include one heterocyclic ring. Suitable substituents for a heterocyclyl group include those hereinbefore defined for an aryl group, as well as oxo.

When used herein, the term 'heteroaryl' includes single and fused rings, each ring suitably comprising up to four, preferably 1 or 2, heteroatoms each selected from oxygen, nitrogen and sulphur. Each ring may have from 4 to 7, preferably 5 or 6, ring atoms. A fused heteroaryl ring may include carbocyclic rings and need include only one heteroaryl ring. Suitable fused heteroaryl rings include bicyclic systems. Suitable substituents for a heteroaryl group include those hereinbefore defined for an aryl group, as well as oxo. Compounds of formula (I) incoφorate a trisubstituted C=C bond and may therefore exist in both the E (natural ) and Z (or iso) geometrical forms. This invention includes both geometrical isomers of formula (I), as well as mixtures of the two isomers. Preferred compounds of formula (I) have an 'E' configuration about the C=C double bond.

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

It will be readily appreciated by the skilled person that the carbon atoms marked with an * in formula (IA) are chiral centres which will give rise to the presence of stereoisomers. The present invention encompasses all such stereoisomers. Suitably the configuration at C* are formally derived from the naturally occuring form of isoleucine, that is they both have the S configuration.

When some of the compounds of this invention are allowed to crystallise, or are recrystallised, from organic solvents, solvent of crystallisation may be present in the crystalline product. This invention includes within its scope such solvates. Similarly, some of the compounds of this invention may be crystallised or recrystallised from solvents containing water which may lead to the formation of hydrated products. This invention includes within its scope stoichiometric hydrates as well as compounds containing variable amounts of water that may be produced by processes such as lyophilisation.

Compounds of the present invention are active, in vitro, as selective inhibitors of isoleucyl t-RNA synthetases from a range of Gram-positive and Gram-negative organisms.

The compounds of this invention are active against both Gram negative and Gram positive organisms, including Bacteroides, for instance B. fragilis BC1, Haemophilus, for instance H. influenzae Ql; Moraxella, for instance M. catarrhalis 1502; Streptococci, for instance S. pyogenes CN10 and S. pneumoniae PU7; Staphylococci, for instance S. aureus Oxford; Escherichia, for instance E. Coli DCO, Legionella, for instance . pneumophila; Pseudomonas, for instance P. aeruginosa Dalgleish and Enterobacter, for instance Ent. faecelis I. In addition, compounds of this invention are active against

Staphylococci organisms such as S. aureus and coagulase negative strains of Staphylocci such as S. epidermidis which are resistant (including multiply-resistant) to other anti¬ bacterial agents, for instance, β-lactam antibiotics such as, for example, methicillin; macrolides; aminoglycosides, and lincosamides. Compounds of the present invention are therefore useful in the treatment of MRS A, MRCNS and MRSE. Furthermore, compounds of the present invention are useful in the treatment of Staphylococci organisms which are resistant to mupirocin. Bacterial infections which may be treated include respiratory tract infections, otitis, meningitis, skin and soft tissue infections in man, mastitis in cattle, and respiratory infections in animals such as pigs and cattle. Accordingly, in a further aspect, the present invention provides a method of treating bacterial infection in human or non-human animals, which method comprises administering a therapeutically effective amount of a compound of formula (I) as hereinbefore defined, to a human or non-human animal in need of such therapy.

The compounds of this invention are also active against mycoplasma-induced infections, in particular infections caused by Mycoplasmafermentans, which has been implicated as a co-factor in the pathogenesis of AIDS. Accordingly in a further aspect, the present invention provides a method of treating humans infected with M. fermentans, in particular humans also infected with HIV, which method comprises treating humans in need of such therapy with an anti-mycoplasmal effective amount of a compound of formula (I).

Compounds of this invention also have antifungal activity. They may, for example, be used in treating fungal infections in man caused by, among other organisms, species of Trichophyton, Trichosporon, Hendersonula, Microsporum, Epidermophyton, Candida, Cryptococcus, Saccharomyces, Paecilomyces and Pityrosporum. They may also be used in the treatment of a variety of other fungal infections caused by, for example Aspergillus, Coccidioides, Paracoccidioides, Histoplasma and Blastomyces species. Accordingly, in a further aspect, the present invention provides for a method of treating fungal infections in animals, including man, which method comprises treating a patient in need of antifungal therapy with an effect amount of a compound of formula (I). Compounds of the present invention are also useful as herbicides and are active against a broad range of weed species, including monocotyledonous and dicotyledonous species. Many compounds show good selectivity in crops, particularly wheat, barley, maize, oil seed rape, sugar beet and rice. Compounds for use in hebicidal compositions of the present invention are preferably applied directly to unwanted plants (post-emergence application) but may also be applied to the soil before the unwanted plants emerge (pre- emergence application). Therefore, in a further aspect, the present invention provides for a process of severely damaging or killing unwanted plants which process comprises applying to the plants or the growth medium of the plants a herbicidally effective amount of a compound of formula (I), as hereinbefore defined.

For herbicidal use, compounds of the present invention are preferably used in the form of a composition further comprising a carrier which may be a liquid or solid diluent. Suitable such compositions may be dilute compositions which are ready for immediate use or concentrated compositions which are diluted prior to use, usually with water. Suitable liquid compositions may comprise a solution or a dispersion of the active ingredient in water, optionally with a surfactant, or may comprise a solution or a dispersion of the active ingredient in a water-immiscible organic solvent which is dispersed as droplets in water. Suitable solid compositions may be in the form of granules or dusting powders or dispersible powders or grains, further comprisng a wetting agent to facilitate dispersion. Suitable herbicidal formulating agents are well known in the art; see, for instance, WO 93/19599 (Zeneca Ltd).

A suitable rate of application for herbicidal use will will depend upon the particular application but will usually be in the range 0.0001 to 20kg/hectare, preferably 0.001 to lOkg/hectare, more preferably 0.001 to 2kg/hectare.

Compounds of the present invention may be used alone or in admixture with other another herbicide which will preferably have a complementary herbicidal activity in the particular application. Suitable such complememtary herbicides are disclosed in WO 93/19599 (Zeneca Ltd).

No adverse toxicological effects are expected from the administration of a compound of formula (I).

This invention also provides a pharmaceutical or veterinary composition which comprises a compound of formula (I) (hereinafter referred to as the 'drug') together with a pharmaceutically or veterinarily acceptable carrier or excipient. The compositions may be formulated for administration by any route, and would depend on the disease being treated. The compositions may be in the foπn of, for instance, tablets, capsules, powders, granules, suppositories, lozenges and liquid or gel preparations, including oral, topical and sterile parenteral 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 poly vinyl-pyrollidone; fillers, for example lactose, sugar, maize-starch, calcium phosphate, sorbitol or glycine; tabletting lubricants, 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, 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 that may be used for the drug are conventional formulations well known in the art, for example, as described in standard text books of pharmaceutics and cosmetics, such as Harry's Cosmeticology, 7th edn, ed Wilkinson and Moore, 1982, George Godwin, Harlow, England and the British Pharmacopoeia.

Suitable ointment formulations include those described in EP 0095 897-A(Beecham Group pic), for pseudomonic acid A (mupirocin), and comprise a polyethylene glycol or a polyethylene glycol analogue or derivative, preferably polyethylene glycol 400 optionally admixed with polyethylene glycol 4000. Suppositories will contain conventional suppository bases, e.g. cocoa-butters or other glyceride.

For parenteral administration, fluid unit dosage forms are prepared utilizing the drug and a sterile vehicle. The drug, depending on the vehicle and concentration used, can be suspended in the vehicle. Advantageously, adjuvants such as a local anaesthetic, preservative and buffering agents can be dissolved in the vehicle. To enhance the stability the composition can be frozen after filling into the vial and water removed under vacuum. The dry lypophilized powder is then sealed in the vial. The drug can be sterilised by exposure to ethylene oxide before suspending in the sterile vehicle.

Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the drug.

For topical application to the ear, the drug may be made up into a suspension in a suitable liquid carrier, such as water, glycerol, diluted ethanol, propylene glycol, polyethylene glycol or fixed oils. For topical application to the eye, the drug is formulated as a suspension in a suitable, sterile aqueous or non-aqueous vehicle. Additives, for instance buffers such as sodium metabisulphite or disodium edetate; preservatives including bactericidal and fungicidal agents, such as phenylmercuric acetate or nitrate, benzalkonium chloride or chlorhexidine, and thickening agents such as hypromellose may also be included.

The dosage employed for compositions administered topically will, of course, depend on the size of the area being treated. For the ears and eyes each dose will typically be in the range from 10 to 100 mg of the drug.

Veterinary compositions for intramammary treatment of mammary disorders in animals, especially bovine mastitis, will generally contain a suspension of the drug in an oily vehicle.

The compositions may contain from 0.1% to 99% by weight, preferably from 10-60% by weight, of the drug, depending on the method of administration. Where the compositions are in unit dose form, each dosage unit will preferably contain from 50-500 mg, of the drug. The dosage as employed for adult human treatment (average weight about 70 kg) will preferably range from 100 mg to 3 g per day, for instance 250 mg to 2 g of the drug per day, depending on the route and frequency of administration. Alternatively, the drug may be administered as part of the total dietary intake of a non-human animal. In this case the amount of drug employed may be less than 1% by weight of the diet and in preferably no more than 0.5% by weight. The diet for animals may consist of normal foodstuffs to which the drug may be added or the drug may be included in a premix for admixture with the foodstuff. A suitable method of administration of the drug to animals is to add it to the non-human animal's drinking water. In this case a concentration of the drug in the drinking water of about 5-500 mg/ml, for example 5-200 mg/ml, is suitable.

Compounds of formula (I) may be readily prepared using procedures well known to those skilled in the art. Thus, compounds of formula (I) may be prepared by a process which comprises treating a compound of formula (II):

(II) in which Z¹ and Z² which may be the same or different is each a hydroxyl protecting group, and n and R^ are as hereinbefore defined; with an activated derivative of a carboxylic acid of the formula:

R²CO2H in which R² is as hereinbefore defined and in which any optional substituents therein may be suitably be protected; in the presence of a suitable base, followed by the removal of any protecting group(s).

Suitable activated derivatives of carboxylic acids are well known to those skilled in the art and include anhydrides, mixed anhydrides, acid chlorides, hydroxsuccinimide esters, and acyl imidazoles. Suitable bases include tertiary amines eg l,8-diazabicyclo[5,4,0]- undec-7-ene.

Suitable protecting groups for optional substituents in the group R² are well known and include: i) for amines, the Boc protecting group which may be removed by treament with acid eg triflouroacetic acid ii) for hydroxyl groups, silyl protecting groups which may be removed by treatment with acid or flouride ion or an acetyl group which may be removed by solvolysis. Suitably, Z¹ and Z² together form an acetal protecting group. Suitable means for removing the acetal hydroxyl protecting group include acidic conditions such as those which are used to remove a Boc protecting group from nitrogen

Compounds of formula (II) may be readily obtained by treating a compound of formula (HI):

(UI) in which n, R*. 7λ and Z² are as hereinbefore defined; with a hydroxyl activating agent, for instance hexabutyldistannnoxane (to form an intermediate tin ether), followed by a sulphamoylating agent, for instance sulphamoyl chloride (H2NSO2CI) under conditions analogous to those described by Castro-Pichel J. et al (Tetrahedron 1987, 43(2), 383-389).

Compounds of formula (HI) may be obtained from readily available starting materials. Two basic strategies may be followed, depending upon the identity of R* and these are illustrated in Schemes la and lb and in Scheme 2. In Schemes la and lb, the 5- substituent of the tetrahydropyran ring is first developed (Scheme la), followed by 2- substituent (Scheme lb). This is useful for compounds of formula (HI) in which R¹ represents C(Me)=CHCOB 1 , C(Me)=CHCONHB², C(OH)=CHCOB⁴ or

that is an α,β-unsaturated ketone, α,β-unsaturated amide, 3-hydroxy ketone or cyclic ketone. In comparison, in Scheme 2 starts from a precursor which already has an appropriate 2-substituent and the 5-substituent of the tetrahydropyranyl ring is then elaborated, to give a compound of formula (III). This is suitable for compounds of formula (III) in which R^l represents C(Me)=CHB³ or a 5-membered heteroaryl ring:

Scheme la

(i) Ozone

(Vll) (VI)

(i) Ozone (ii) Me₂S n = 1

Na BH₄

(VIII)

in which scheme R^ is H or a C(i_6₎alkyl group, for instance ethyl, Z³ is a hydroxyl protecting group; and n, Z* and Z² are as hereinbefore defined;

In Scheme la, compounds of formula (IV) are (protected) esters of monic acid C and may conveniently be prepared from monic acid A by first forming an ester, for instance the ethyl ester, according to the procedures described in GB 1 587 059 (Beecham Ltd) and then converting the epoxide moiety of the intermediate ester into a double bond by using a suitable deoxygenating agent, according to the procedures described in WO 94/26750 (SmithKline Beecham pic) and references therein. Monic acid A itself may be readily obtained from pseudomonic acid A by carefully controlled hydrolysis, according to the procedure described in GB 1 587 058 (Beecham Ltd).

Scheme lb

(III) in which scheme B 1 , R^, Z^ , Z², Z³ and n are as hereinbefore defined;

In Scheme lb, compounds of formula (III) in which R¹ represents C(Me)=CHCOBl may be prepared from compounds of formula (IX) by treatment thereof with a suitable organometallic reagent comprising the group B ¹, for instance an organolithium reagent B ! Li or a Grignard reagent B 1 MgHal, as described in earlier applications EP 0029 665- A, WO 91/09855, WO 92/02518. The reaction of an N-methoxy-N-methylamide with an organolithium or a Grignard reagent to form a ketone is also described by Nahm and Weinreb in Tetrahedron Letters, 1981, 3815. The reaction with the organometallic reagent may be conveniently carried out in an ethereal or hydrocarbon solvent, the choice of which is dependent upon the specific requirements of the organometallic reagent. Preferably, the Grignard reagent is generated and used in diethyl ether or tetrahydrofuran. The reaction is generally carried out in an inert atmosphere such as argon or nitrogen and at ambient temperature or below.

Compounds of formula (III) in which R¹ represents C(Me)=CHCONHB² may be obtained form compounds of formula (VI) by analogy with the processes described in earlier application EP 0 001 914-A (Beecham Group). Suitably, the compound of formula (VI) is converted into a corresponding derivative in which the carboxy group is activated, for instance a reactive ester or a a mixed anhydride, and then treated with an amine NH2B²under amide forming conditions.

Compounds of formula (III) in which R¹ represents C(OH)=CHCOB⁴ may be obtained from compounds of formula (VI) by analogy with the processes described in earlier application WO 93/06118 (SmithKline Beecham pic).

Compounds of formula (ITI) in which R represents:

may be obtained form compounds of formula (VI) by analogy with the processes described in earlier application WO 94/02478 (SmithKline Beecham pic).

In an alternative strategy, intermediate compounds of formula (IH) in which R represents C(Me)=CHB³ or HET may be prepared according to the route described in Scheme 2. Scheme 2

(XII)

(XI) (i) ozone

(ii) dimethyl sulphide

(X«V) (XIII)

(i) ozone NaBH.

(li) dimethyl sulphide

(n = 2)

(XV) (III)

in which Rl, Z¹, Z² and Z³ are as hereinbefore defined.

Compounds of formula (XI) in which R* represents C(Me)=CHB³ are analogues of monic acid in which the ester moiety has been replaced by an aryl or a heteroaryl moiety. Such compounds and processes for the preparation thereof have been previously described in our earlier patent applications EP 0 087 953-A, EP 0 123 378-A,

EP 0 352909- A, EP 0 399 645- A and WO 91/09856. Compounds of formula (XI) may then be converted into compounds of formula (XD) using the deoxygenaing procedures described in WO 94/26750 (SmithKline Beecham pic) and references therein.

Compounds of formula (XI) in which Rl represents HET are analogues of monic acid in which the α,β-unsaturated ester moiety has been replaced by a heteroaryl moiety. Such compounds and processes for the preparation thereof have been previously described in our earlier patent application WO 95/16686 (SmithKline Beecham pic). When used herein, the term 'hydroxyl-protecting group' refers to any such group known in the art which may be removed without disruption of the remainder of the molecule. Suitable hydroxyl-protecting groups are described in Protective Groups in Organic Synthesis, T.W. Greene and P M G Wuts, Wiley-Interscience, New York, 2nd ed, 1991. Their use in pseudomonic acid chemistry is described in earlier patent applications, for instance WO 94/26750 (SmithKline Beecham pic). It will be readily appreciated that the hydroxyls of glycol function of the tetrahydropyran ring may also be protected together, by a suitable protecting group. The term 'hydroxyl-protecting group' also refers to such protecting groups. Particularly suitable protecting groups include silyl groups and, for the the glycol function of the tetrahydropyran ring, ortho esters and ketals.

The invention will now be described by the following examples (nmr assignments have been made using the numbering system conventionally used for pseudomonic acid derivatives):

Example 1 : {3R,4R-Dihydroxy-2S-[3(E)-(5-(3-methyIisoxazol-5-yl)oxazoI-2-yl)-2- methylprop-2-en-l-yl]tetrahydropyran-5R-yl}methyl (2S,3S)-2-amino-3-rnethyl-l- oxopent- 1 -ylsulfamate. a) 5-(3-Methylisoxazol-5-yl)-2-(l-noπτ.on-2-yl)oxazole C 5-(3-Methylisoxazol-5-yl)-2-(l-normon-2-yl)oxazole A (EPA 87953 and 123378) (8.97g, 20mmol) was dissolved in dichloromethane (160ml), cooled in an ice/salt bath, and treated sequentially with pyridine (9.7ml, 120mmol) and trichloroacetyl chloride (11.1ml, 90mmol). Stirred for 2^I/2h, then diluted with ethyl acetate, washed with 5% aqueous citric acid, saturated aqueous sodium hydrogen carbonate, and brine, dried and evaporated to give an off-white foam (18.6g).

This foam was dissolved in acetonitrile (60ml) and added to a pre-stirred (5min) mixture of dry sodium iodide (14.99g, lOOmmol) and trifluoroacetic anhydride (4.23ml, 30mmol) in acetonitrile (60ml) cooled in an ice/salt bath. The mixture was stirred overnight in the dark, then diluted with diethyl ether, washed with 10% aqueous sodium metabisulfite (x2), saturated aqueous sodium hydrogen carbonate, and brine, dried and evaporated to give a brown foam (17.5g).

This foam was dissolved in methanol (100ml), and potassium carbonate (11.06g, 80mmol) added. The mixture was stirred for IVih, then diluted with water and extracted with ethyl acetate (x3). The combined organic extracts were washed with brine, dried and evaporated. The residue was purified by flash chromatography on silica (120g), eluting with 0-4% methanol in dichloromethane, to give the title compound as a cream foam (4.06g, 47%); δ_H(CD₃OD) (inter alia) 1.01 (3H, d, 76.9Hz, 17-H₃), 1.11 (3H, d, 76.4Hz, 14-H₃), 2.31 (3H, s, 15-H₃), 2.35 (3H, s, l'"-H₃), 5.41-5.59 (2H, m, 10-H, 11- H), 6.29 (IH, s, 2-H), 6.61 (IH, s, 4"-H), and 7.65 (IH, s, 4'-H); m/z 432 ( +, 8%) and 204 (100). (Found: M⁺, 432.2270. C23H3₂N₂O₆ requires Λf, 432.2260). b) 2-[3-{(3aS,4S,7S,7aR)-2,2-Dimethyl-7-(2-oxoethyl)-3a,6,7,7a-tetτahydro-4H- l,3-dioxolo[4,5-c]pyran-4-yl}-2-methylprop-l(E)-en-l-yI]-5-(3-methyI-isoxazol-5- yl)oxazoIe.

The product from Example la (4.05g, 9.36mmol) was dissolved in dry THF (50ml), and 2,2-dimethoxypropane (25ml) added followed by 4-toluenesulphonic acid (0.45g). The mixture was stirred for 45min, then diluted with ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate and brine, dried and evaporated to give the crude acetonide (4.47g, quant.). The crude acetonide (2.36g, 5mmol) was dissolved in dry DMF (10ml), then imidazole (0.68 lg, lOmmol) added followed by t-butyldiphenylchlorosilane (1.7ml, 6.5mmol). The mixture was heated at 55°C for 18h, then at 80°C for lh. The volume of the reaction was reduced in vacuo, the mixture cooled, diluted with diethyl ether, washed with water and brine, dried and evaporated. The crude product was purified by flash chromatography, eluting with 12-15% ethyl acetate in hexane, to give the protected product as a colourless gum (3.201g, 90%).

The protected compound (4.165g, 5.86mmol) was dissolved in dichloromethane (60ml) and ethanol (30ml) and ozonised at -70°C for a total of 14min. Dimethyl sulphide (0.86ml, 11.7mmol) was then added, and the mixture stirred for 15min at -70°C and 2h up to room temperature. The solution was then evaporated to dryness to give a gum. This was purified by column chromatography on silica ( 105g), eluting with 50-80% diethyl ether in hexane, to give the title compound as a colourless gum (1.980g, 84%); δ_H(CDCl₃) (inter alia) 1.37 and 1.53 (6H, 2s, 2 x CH₃), 2.29 (3H, s, 15-H₃), 2.35 (3H, s, 1"'-H3), 6.26 (IH, s, 2-H), 6.31 (IH, s, 4"-H), 7.53 (IH, s, 4'-H), and 9.82 (IH, s, CHO); m/z 402 (M+, 10%), 204 (37), and 43 (100). (Found: M+, 402.1793. C₂ιH₂6N2θ₆ requires M, 402.1791). c) 2-[3-{(3aS,4S,7S,7aR)-2^-DimethyI-7-hydroxyrnethyl-3a,6,7,7a-tetrahydro- 4H-1 -dioxolo[4,5-c]pyran-4-y]}-2-methylprop-l(E)-en-l-yI]-5-(3-methylisoxazol-5- yl)oxazole

The aldehyde from Example lb (2.24g, 5.56mmol) was dissolved in toluene (40ml), and treated sequentially with triethylamine (1.16ml, 8.35mmol) and triisopropylsilyl trifluoromethanesulfonate (1.65ml, 6.12mmol). The solution was stirred for 5h, during which time it became cloudy. The crude reaction mixture was then chromatographed on silica (75g), eluting with 0-32% diethyl ether in hexane, to give the triisopropylsilylenol ether (1.57g, 51%). This enol ether was then dissolved in dichloromethane (30ml) and ethanol (15ml), and ozonised at -70°C for a total of 6min. Sodium borohydride (106ml, 2.8mmol) was then added, and the mixture stirred at -70°C for lh. A further equivalent of sodium borohydride (106mg, 2.8mmol) was then added, and the cooling bath removed. After stirring for lh, the mixture was diluted with ethyl acetate, washed with water and brine, dried and evaporated to give an oil. This material was purified by column chromatography on silica (36g), eluting with 50-65% ethyl acetate in hexane, to give the tide compound as a white gum (0.620g, 57%); δπ(CDCl3) (inter alia) 1.39 and 1.54 (6H, 2s, 2 x CH₃), 2.30 (3H, d, J0.6Hz, 15-H₃), 2.36 (3H, s, 1"'-H₃), 6.25 (IH, s, 2-H), 6.31 (IH, s, 4"-H), and 7.53 (IH, s, 4'-H); m/z 390 (M+, 12%) and 204 (100). (Found: M+, 390.1793. C20H26N2O6 requires M, 390.1791). d) 2-[3-{(3aS,4S S aR)-2,2-Dimethyl-7-sulfamidylmethyl-3a,6,7,7a- tetrahydro-4H-l,3-dioxolo[4,5-c]pyran-4-yl}-2-methylprop-l(E)-en-l-yl]-5-(3- methylisoxazoI-5-yI)oxazole

The alcohol from Example lc (0.610g, 1.56mmol) was dissolved in benzene (35ml), hexabutyldistannoxane (1.59ml, 3.12mmol) added, and the mixture refluxed with a Dean and Stark apparatus for 3h. The mixture was then cooled to 10°C, and a solution of sulfamoyl chloride (0.793g, 6.86mmol) in dioxan (10ml) added. After stirring vigorously for V. at room temperature, the mixture was cooled in an ice bath, and saturated aqueous sodium hydrogen carbonate added. The mixture was stirred for two minutes, then ethyl acetate added. The phases were separated, and the organic washed with brine, dried and evaporated to give a gum (2.5g). This was purified by column chromatography on silica (24g), eluting with 40-50% ethyl acetate in hexane, to give the title compound as a colourless gum (0.161g, 22%); δπ(CDCl3) (inter alia) 1.37 and 1.52 (6H, 2s, 2 x CH₃), 2.28 (3H, d, J 0.7Hz, 15-H₃), 2.35 (3H, s, r"-H₃), 5.30 (2H, s, NH₂), 6.28 (IH, s, 2-H), 6.36 (IH, s, 4"-H), and 7.52 (IH, s, 4'-H); m/z 469 ( +, 7%), 204 (60), and 83 (100). (Found: M+, 469.1513. C20H27N3O8S requires M, 469.1519). A further, impure sample of the title compound (0.253g) was also obtained. e) {3R,4R-Dihydroxy-2S-[3(E)-(5-(3-methylisoxazol-5-yI)oxazoI-2-yl)-2- methyIprop-2-en-l-yl]tetrahydropyran-5R-yl}methyl (2S S)-2-arnino-3-methyl-l- oxopent-1-ylsulfamate. N-tBoc-L-isoleucine (0.116g, 0.5mmol) was dissolved in dry THF (3ml), and carbonyldiimidazole (0.130g, O.δmmol) added. The mixture was stirred for V.h, with gentle warming. The sulfamate from Example Id (0.157g, 0.33mmol) in THF (4ml) was then added, followed by l,8-diazabicyclo[5.4.0]-undec-7-ene (0.055ml, 0.36mmol). After stirring for lVih, the mixture was diluted with ethyl acetate, washed with 5% aqueous citric acid, and brine, dried and evaporated to give a white foam (0.27g). This material was purified by column chromatography on silica (9g), eluting with 0-5% methanol in dichloromethane, to give the protected compound (0.161g, 72%). This product (0.144g, 0.21mmol) was dissolved in ethanol (4ml), and trifluoroacetic acid (4ml) added slowly. After stirring for VA, the mixture was evaporated. The residue was dissolved in trifluoroacetic acid (5ml) and stirred for lOmin. This solution was then evaporated to dryness, and again from ethanol. The crude product was purified by column chromatography on HP20SS eluting with 0-25% THF in water. The product containing fractions were combined, reduced in volume, and freeze dried to give the title compound as a white fluffy solid (0.096g, 85%); v_max (KBr) 3437, 2925, 1647, 1629, 1296, and 1146cm-¹; λ_max (H2O) 301nm (ε_m 25,800); HPLC ion chromatography showed no trifluoroacetate ions to be present; δπ(D2θ) 0.89 (3H, t, 77.3Hz, 5'-H3), 0.99 (3H, d, 77.0Hz, 6'-H₃), 1.11-1.58 (2H, m, 4'-H₂), 1.92-2.08 (IH, m, 8-H), 2.15 (3H, s, I5-H3). 2.27 (4H, s + m, 1"^*-H₃, 3'-H), 2.44 (IH, dd, 7 10.0 and 14.8Hz, 4-H), 2.67 (IH, br d, 7 14.8Hz, 4-H), 3.52-3.87 (4H, m, 16-H₂, 6-H, 2'-H), 3.92-4.28 (4H, m, 9-H₂, 7-H, 5-H), 6.18 (IH, s, 2-H), 6.50 (IH, s, 4"-H), and 7.51 (IH, s, 4'-H); m/z (CI) 543 (Λ H+, 1%) and 131 (100); m/z (Electrospray) 1085 (2M + H⁺, 15%) and 543 (MH+, 100).

Example 2: {3R,4R-Dihydroxy-2S-[2-methyl-4-oxo-4-(4-propylthiophenyl)but-2-en- l-yl]tetrahydropyran-5R-yl}methyl (2S_r3S)-2-amino-3-methyl-l-oxopent-l- ylsulfamate. a) Ethyl 4-{(3aS,4S,7S,7aR)-2,2-dimethyl-7-(2-oxo€thyI)-3a,6,7,7a-tetrahydro- 4H-l,3-dioxolo [4,5-c]pyran-4-yl}-3-methylbut-2(E)-enoate A mixture of ethyl monate C (3.5g, 9.8mmoles), 2,2-dimethoxyproρane (20ml, 0.16 moles), dry THF (30ml) and p-toluenesulphonic acid (0.4g) was stirred for lh at 20°C. Ethyl acetate (50ml) was added and the solution washed with saturated aqueous sodium hydrogen carbonate (30ml) and brine (30ml). The solution was dried over anhydrous magnesium sulphate and evaporated to give the crude acetonide (3.86g, quant). To the crude acetonide (2.2g, 5.5mmoles) in dry THF (20ml), triethylamine (1.16ml, 8.2 mmoles) followed by chlorotrimethylsilane (1.05ml, mmoles) and 4- dimethylaminopyridine (20mg) was added. The solution was stirred at 20°C for 2h, filtered and evaporated to dryness. Hexane (40ml) was added and the solution washed with water (40ml), saturated aqueous hydrogen carbonate solution and brine. It was dried and evaporated to give the crude 13-trimethylsilyl protected olefin (2.5g, 95%). The protected olefin (2g, 4.2mmoles) was dissolved in dichloromethane (35ml)/ethanol (20ml) and ozonised at -70°C in l-2min intervals each time monitoring the reaction by tic until all the starting material had just disappeared. Dimethyl sulphide (0.7ml) was added and the solution stirred for 2h at 20°C. It was diluted with ethyl acetate, washed with water, dried over anhydrous magnesium sulphate and evaporated. The crude product was purified by flash chromatography on silica gel eluting with hexane :ethyl acetate 3:1 gave the tide aldehyde (lg,72%) as a colourless oil; δπ(CDCl3) 1.27 (3H, t, 76.9Hz, 2"-H), 1.35 (3H, s, CMe), 1.5 (3H, s, CMe), 2.15-2.25 (4H, m, 15-H₃ and 4-H), 2.58-2.79 (3H, m, 9-H₂ and 8-H), 3.46 (IH, dt, 73 and 9Hz, 5H), 3.59 (IH, d, 7 12Hz, 16-H), 3.69 (IH, dd, 75 and 9Hz, 6-H), 3.75 (IH, dd, 73 and 12Hz, 16-H), 4.06 (IH, bs, 7-H), 4.16 (2H, q, 77, 1"-H), 9.81 (IH, s, CHO). b) Ethyl 4-{(3aS,4S,7S,7aR)-2,2-dimethyl-7-hydroxymethyl-3a,6,7,7a- tetrahydro-4H-l,3-dioxolo [4,5c] pyran-4-yI}-3-methylbut-2(E)-enoate

To the aldehyde from Example 2a (0.6g, 1.8 mmoles) in toluene (10ml), triethylamine (0.37ml, 2.7 mmoles) was added at 5°C followed by triisopropylsilyl trifluoromethanesulfonate (0.55ml, 1.98mmoles). The resulting solution was stirred at room temperature for 2 hours. The crude reaction mixture was placed directly onto a silica gel column and eluted with hexane → hexane:Ethyl acetate 9: 1 to give the triisopropylsilylenol ether (0.6g, 67% yield) as an oil; m/z MH⁺ 483. The triisopropylsilylenol ether (0.2 lg, 4.35 mmoles) was dissolved in dichloromethane (3ml) and ethanol (2ml) and treated with ozone at -70°C in 15 second intervals each time monitoring the reaction by tic until the starting material had just disappeared. It was then treated with sodium borohydride (20mg, 4.35 mmoles) and stirred at -70°C for 1 hour. A further equivalent of sodium borohydride (20mg, 4.35 mmoles) was added and the reaction stirred at room temperature for 1 hour. After this time acetic acid (0.1ml) was added, the reaction was diluted with ethyl acetate, washed with water and brine, dried over anhydrous magnesium sulfate and evaporated. The crude product was purified by column chromatography on silica gel eluting with 4:1 hexane:ethyl acetate to give the title alcohol (44mg, 60%) as an oil; δ_H(CDCl₃) 1.29 (3H, t, 77.11Hz, 2"-H₃), 1.39 (3H, s, CMe), 1.52 (3H, s, CMe), 2.1-2.2 (5H, m, 15-H₃, 4-H and 8-H), 2.5 (IH, d, 7 13.7Hz, 4-H), 3.45 ( IH, ddd, 72.7Hz, 5-H), 3.75-3.9 (5H, m, 16-H₂, 9-H₂. 6-H), 4.15 (2H, q, J 7.1Hz, 1"-H), 4.3 (IH, m, 7-H), 5.75 (IH, s, 2-H); m/z M+ 314. c) Ethyl 4-{(3aS,4S,7S,7aR)-2,2-dimethyl-7-(tbutyldiιnethylsilyloxymethyl)- 3a,6,7/7a-tetrahydro-4H-l,3-dioxolo[4,5-c]pyran-4-yl}-3-methylbut-2(E enoate To a solution of the hydroxymethyl compound from Example 2b (2.20g, 7mmol) in dry DMF (15ml) was sequentially added imidazole (0.953g, 14mmol) and tbutyldimethylchlorosilane (1.79g, 11.9mmol). The mixture was stirred at 40°C for 18h, then more imidazole (0.68 lg, lOmmol) and tbutyldimethylchlorosilane (1.21g, 8mmol) were added, and stirring continued for a further V. . The mixture was diluted with water and extracted with hexane (x2). The combined organic extracts were washed with brine, dried and evaporated to give an oil (4.2g). This material was purified by flash chromatography, eluting with 0-6% ethyl acetate in hexane, to give the title compound as a viscous oil (2.775g, 93%); δ_H(CDCl₃) (inter alia) 0.06 (6H, s, 2 x SiCH ), 0.89 (9H, s, SitBu), 1.27 (3H, t, 77.1Hz, CH₃), 1.37 and 1.51 (6H, 2s, 2 x CH₃), 2.20 (3H, d, 7 1.1Hz, 15-H₃), 4.14 (2H, q, 77.1Hz, OCH₂), and 5.74 (IH, d, 70.8Hz, 2-H). d) N-Methoxy-N-methyl 4-{(3aS,4S,7S,7aR)-2,2-dimethyl-7-(tbutyIdimethyl- silyloxymethyl)-3a,6,7,7a-tetrahydro-4H-l,3-dioxolo[4,5-c]pyran-4-yl}-3-methylbut- 2(E)-enamide n-Butyllithium (30ml, 1.5M, 45mmol) was added slowly to a solution of dry N,O- dimethylhydroxylamine hydrochloride (2.5 lg, 25.8mmol) in dry THF (40ml) at -10°C. The mixture was stirred for 15min, cooled to -20°C, and a solution of the ethyl ester from Example 2c (2.76g, 6.44mmol) in dry THF (10ml) added slowly. After stirring for Vih at -20°C to -5°C the reaction was quenched by the addition of saturated aqueous ammonium chloride. The mixture was extracted with ethyl acetate (x2), and the combined organic extracts washed with brine, dried and evaporated to give an oil (3.0g). This material was purified by flash chromatography on silica (40g), eluting with 10-20% ethyl acetate in hexane, to give the title compound as a colourless oil (2.787g, 98%); 6H(CDC13) (inter alia) 0.06 (6H, s, 2 x SiCH₃), 0.89 (9H, s, tBu), 1.36 and 1.51 (6H, 2s, 2 x CH₃), 2.16 (3H, s, 15-H₃), 3.20 (3H, s, NCH3), 3.67 (3H, s, NOCH3), and 6.19 (IH, s, 2-H); m/z (CI) 461 ( NH4+, 50%) and 444 (MH+, 100); m/z 444 (MH+, 8%) and 171 (100). (Found: Λ H+, 444.2775. C22H42NO6Si requires M, 444.2781). e) 4-{(3aS,4S,7S,7aR)-2,2-Dimethyl-7-(tbutyldimethylsilyloxymethyl)-3a,6,7,7a- tetrahydro-4H-1 -dioxolo[4,5-c]pyran-4-yI}-3-methyl-l-oxo-l-(4- propyl thiophenyl)but-2(E)-ene

4-(Propylthio)bromobenzene (0.878g, 3.8mmol) in THF (20ml) was cooled to -70°C, and treated slowly with nbutyllithium ( 1.5M, 2.53ml, 3.8mmol). After stirring for 45min, the amide from Example 2d (1.375g, 3.1mmol) in THF (10ml) was added slowly. The mixture was stirred at -70°C to -50°C for VΛh, then quenched with glacial acetic acid (0.23ml). Brine was then added and the mixture extracted with diethyl ether. The organic phase was separated, dried and evaporated to give an oil (1.86g). This material was purified by column chromatography on silica (44g), eluting with 0-30% ethyl acetate in hexane, to give the title compound as an oil (0.760g, 46%); δπtCDC^) (inter alia) 0.07 (6H, s, 2 x SiCH₃), 0.90 (9H, s, tBu), 1.05 (3H, t, 77.3Hz, CH3), 1.38 and 1.52 (6H, 2s, 2 x CH3), 2.20 (3H, d, 7 1.1Hz, 15-H₃), 2.97 (2H, t, 77.3Hz, SCH₂), 6.75 (IH, s, 2-H), 7.24-7.32 (2H, m, 2ArH), and 7.81-7.88 (2H, m, 2ArH); m/z 534 (M+, 0.5%), 519 (3), 477 (20), 419 (5), and 179 (100); m/z (CI) 535 (MH+, 20%), 458 (40), 264 (65), and 91 (100). f) 4-{(3aS,4S,7S,7aR)-2,2-Dimethyl-7-hydroxymethyl-3a,6,7,7a-tetrahydro-4H- l,3-dioxolo[4,5-c]pyran-4-yl}-3-methyl-l-oxo-l-(4-propylthiophenyl)but-2(E)-ene The silyl ether from Example 2e (0.630g, 1.18mmol) was dissolved in THF (15ml), and treated sequentially with glacial acetic acid (0.67ml, 1 l.δmmol) and tetrabutylammonium fluoride (1.0M in THF, 5.9ml, 5.9mmol). The mixture was stirred for 15'/2h. Ethyl acetate was then added, the mixture washed with saturated aqueous sodium hydrogen carbonate and brine, dried and evaporated. The residual oil was purified by flash chromatography, eluting with 20-46% ethyl acetate in hexane, to give the title compound as a colourless oil (0.497g, 100%); δ_H(CDCl₃) (inter alia) 1.06 (3H, t, 77.3Hz, CH3), 1.40 and 1.53 (6H, 2s, 2 x CH3), 2.20 (3H, d, 70.9Hz, 15-H₃), 2.97 (2H, t, 77.3Hz, SCH₂), 6.74 (IH, d, 70.7Hz, 2-H), 7.25-7.33 (2H, m, 2ArH), and 7.80-7.87 (2H, m, 2ArH); m/z 420 (M+, 11%) and 179 (100). (Found: M+, 420.1972. C23H32O5S requires M, 420.1970). g) 4-{(3aS,4S,7S,7aR)-2,2-Dimethyl-7-sulfamidylmethyl-3a,6,7,7a-tetrahydro- 4H-l,3-dioxolo[4,5-c]pyran-4-yl}-3-methyl-l-oxo-l-(4-propylthiophenyI)but-2(E)- ene

The title compound was prepared from the alcohol in Example 2f (0.463g, l.lmmol) by the method described in Example Id. A colourless gum (0.290g, 53%) was obtained; δ_H(CDCl3) (inter alia) 1.06 (3H, t, 77.3Hz, CH3), 1.39 and 1.53 (6H, 2s, 2 x CH3), 2.18 (3H, d, 70.8Hz, 15-H₃), 2.97 (2H, t, 77.3Hz, SCH₂), 4.96 (2H, br s, NH₂), 6.73 (IH, s, 2-H), 7.25-7.32 (2H, m, 2ArH), and 7.78-7.86 (2H, m, 2ArH); m/z 499 (M+, 4%) and 179 (100). (Found: ⁺, 499.1698. C23H33NO7S2 requires M, 499.1698). h) {3R,4R-Dihydroxy-2S-[2-methyl-4-oxo-4-(4-propylthiophenyl)but-2-en-l- yl]tetrahydropyran-5R-yl}methyl (2S S)-2-amino-3-methyl-l-oxopent-l- ylsulfamate.

Using the method described in Example le the sulfamate from Example 2g (0.305g, 0.61 mmol) was coupled and deprotected to give the title compound as a colourless gum (0.022g); HPLC and nmr indicated an E:Z mixture approximately 3:1; δπ(CD30D) 0.84-1.11 (9H, m, 3 x CH3), 1.15-1.85 (5H, m, 3'-H, 4'-H₂, CH ), 1.91-2.04 (IH, m, 8- H), 2.12 (0.75H, s, 15-H₃ Z), 2.20 (2.25H, s, 15-H₃ E), 2.21-2.85 (2H, m, 4-H₂), 2.9-3.1 (2H, m, SCH₂), 3.2-4.3 (8H, m, 2'-H, 5-H, 6-H, 7-H, 16-H₂, 9-H₂), 6.86 (0.75H, s, 2-H E), 6.93 (0.25H, s, 2-H Z), 7.34-7.39 (2H, m, 2ArH), and 7.85-7.91 (2H, m, 2ArH); m/z (Cl) 573 (MH+, 5%), 477 (22), 363 (49), 284 (51), 212 (83), and 195 (100); m/z (Electrospray) 1145 (2M + H+, 18%), 573 (MH+, 84), and 284 (100).

Examples 3 to 9 were prepared in a similar manner to Example 1, using as starting material an appropriate 5-(phenyl/heteroaryl)-2-(l-normon-2-yl)oxazole A compound. Methods for preparing such are described in EP 0 087 953-A, EP 0 339 645-A and WO 91/09856.

Example 3 - {3R,4R-Dihydroxy-2S-[3(E)-(5-phenyloxazoI-2-yl).2-methylprop-2-en- l.yl]tetrahydropyran-5R-yl}methyI-(2S^S)-2-aιτιino-3-methyl-l-oxopent-l-yl sulfamate δ_H (D₂0) 0.9 (3H, t, J 7Hz, 5'-H₃), 1.0 (3H, d, J 7Hz, 6'-H₃), 1.1-1.6 (2H, m, 4'-H₂), 1.9-2.1 (IH, m, 8-H), 2.2 (3H, m, 15-H₃), 2.3 (IH, s, 3'-H), 2.4 (IH, dd, J 10 and 15Hz, 4-H), 2.7 (IH, br d, J 15Hz, 4-H), 3.5-3.9 (4H, m, 16-H₂, 6-H, 2^*-H), 3.9-4.3 (4H, m, 9- H₂, 7-H, 5-H), 6.2 (IH, s, H-2), 7.2-7.8 (6H, m, 4'-H, aryl); /z (El) 537 (MH+, 1%) and 199 (100).

Example 4 - {3R,4R-Dihydroxy-2S-[3(E)-(4-cyanofur-2-yl)oxazol-2-yl)-2- methylprop-2-en-l-yI]tetrahydroρyran-5R-yI}methyl-(2S,3S)-2-amino-3-methyl-l- oxopent-1-yl sulfamate δ// (D₂0) 0.9 (3H, t, J 7Hz, 5'-H₃), 1.0 (3H, d, J 7Hz, 6'-H₃), 1.1-1.6 (2H, m, 4'-H₂), 1.9-2.1 (IH, m, 8-H), 2.1 (3H, s, 15-H₃), 2.3 (4H, ra, 3'-H), 2.5 (IH, dd, J 10 and 15Hz, 4-H), 2.7 (IH, br d, J 15Hz, 4-H), 3.5-4.0 (4H, m, 16-H₂, 6-H, 2'-H), 3.9-4.3 (4H, m, 9- H₂, 7-H, 5-H), 6.2 (IH, s, 2-H), 7.0 (IH, s, 5"-H), 7.5 (IH, s, 4'-H), 8.4 (IH, s, 2"-H); m/z (El) 552 (MH+, 1%) and 214 (100). Found MH+ = 552.1883. C24H32N4O9S requires 552.1889. Example 5 - {3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylsulfonyl)phenyI)oxazol-2-yl)-

2-methylprop-2-en-l-yI]tetrahydropyran-5R-yl}methyl (2S,3S)-2-amino-3-methyl-l- oxopent-l-ylsulfamate δ_H(CD₃OD) 0.96 (3H, t, 77.3Hz, 5'-H₃), 1.04 (3H, d, 77.0Hz, 6'-H₃), 1.17-1.35 (IH, m, 4'-H), 1.52-1.70 (IH, m, 4'-H), 1.94-2.06 (IH, m, 8-H), 2.14-2.23(1H, m, 3'-H), 2.30- 2.44(4H, s+m, 15-H₃, 4-H), 2.77 (IH, br d, 714.8Hz, 4-H), 3.15 (3H, s, -SO₂CH₃), 3.41 (IH, dd, 78.7,3.1Hz, 6-H),3.55 (IH, d, 74.0Hz, 2'-H), 3.59-4.28 (6H, m, 16-H₂, 7-H, 5- H, 9-H₂), 6.28 (IH, s, 2-H), 7.73 (IH, s, 4"-H), and 7.89-8.04 (4H, m, 4Ar-H); m/z (electrospray, -ve ion) 728 (M-H+TFA, 100%) and 614 (M-H, 22%).

Example 6 - (3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylthio)phenyl)oxazol-2-yl)-2- methylprop-2-en-l-yl]tetrahydropyran-5R-yl}me yl (2S S)-2-amino-3-methyl-l- oxopent- 1-ylsulfamate δ_H(CD₃OD) 0.96 (3H, t, 77.3Hz, 5'-H₃), 1.04 (3H, d, 77.0Hz, 6'-H₃), 1.18-1.75 (2H, m, 4'-H₂), 1.92-2.07 (IH, m, 3'-H), 2.13-2.23(1H, m, 8-H), 2.29 (3H, s, 15-H₃), 2.35 (IH, dd, 714.5,9.5Hz, 4-H), 2.50 (3H, s, SCH₃), 2.75 (IH, br d, 714.5Hz, 4-H), 3.42 (IH, dd, 78.7,3.1Hz, 6-H),3.56 (IH, d, 74.1Hz, 2'-H), 3.62-3.71 (IH, m, 16-H), 3.79-3.91 (2H, m, 5-H.16-H), 4.04-4.09 (IH, m, 7-H),4.14-4.31 (2H, m, 9-H₂), 6.23 (IH, s, 2-H), 7.28- 7.34 (2H, m, 2Ar-H), 7.43 (IH, s, 4"-H), and 7.56-7.64 (2H, m,

m/z (electrospray, -i-ve ion) 584 (MH+, 70%).

Example 7 - {3R,4R-Dihydroxy-2S-[3(E)-(5-(4-chloropyridin-5-yl)oxazoI-2-yl)-2- methylprop-2-en-l-yl]tetrahydropyran-5R-yl}methyl-(2S^S)-2-amino-3-methyl-l- oxopent-1-yl sulfamate δ_H (CD₃OD) 0.94 (3H, t, 77.3Hz, 5'-H₃), 1.05 (3H, d, 77.0Hz, 6'-H₃), 1.2-1.7 (2H, m, 4'-H₂), 2.0 (IH, m, 3'-H), 2.2 (lH,m, 8-H), 2.3 (3H, s, 15-H₃), 2.35 (lH,m, 4-H), 2.8 (IH, br d, 7 14.4Hz, 4-H), 3.4-3.9 (5H, m, 16-H₂, 6-H, 5-H, 2'-H), 4.05 (IH, bs, 7-H) 4.2 (2H, m, 9-H₂), 6.3 (IH, s, 2-H), 7.50 (IH, d, 78.4Hz 5"-H), 8.1 (lH,dd, 78.4, 2.5Hz, 4"- H), and 8.7 (IH, d, 72.5Hz, 2"-H); m/z (-ve electrospray) 685,687 (M - H + TFA.100, 40%) and 571 (M - H, 15%).

Example 8 - {3R,4R-Dihydroxy-2S-[3(E)-(5-(4-methylphenyI)oxazol-2-yl)-2- methylprop-2-en-l-yI]tetrahydropyran-5R-yl}methyl-(2S S)-2-amino-3-methyl-l- oxopent-l-yl sulfamate 6_H (CD₃OD) 0.98 (3H, t, 77.4Hz, 5'-H₃), 1.06 (3H, d, 77.0Hz, 6'-H₃), 1.19-1.38 (IH, m, 4'-H), 1.51-1.72 (IH, m, 4'-H), 2.00 (IH, m, 3'-H), 2.20 (IH, m, 8-H), 2.31 (3H, s, 15- H₃), 2.38 (3H, s, 4"'-H₃), 2.40 and 2.76 2H, ABq, 7 13.9Hz, 4-H₂), 3.42 (IH, dd, 73.1 and 8.6Hz, 6-H), 3.56 (IH, d, 74.0Hz, 2'-H), 3.68 (IH, ABq, 7 11.6Hz, 16-H), 3.87 (2H, m, 5-H, 16-H), 4.09 (IH, m, 7-H), 4.22 (2H, m, 9-H₂), 6.26 (IH, s, 2-H), 7.27 (2H, d, 7 8.0Hz, 3"'-H, 5"^*-H), 7.44 (IH, s, 4"-H), and 7.70 (2H, d, 78.0Hz, 2"'-H, 6"'-H); /z (electrospray) 552 (MH+) and 574 (MNa+).

Example 9 - {3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylsuIfinyl)phenyl)oxazol-2-yl)- 2-methyIprop-2-en-l-yl]tetrahydropyran-5R-yl}methyl (2S,3S)-2-amino-3-methyl-l- oxopent- 1 -ylsulf amate δ_H(CD30D) 0.93 (3H, t, 77.3Hz, 5'-H₃), 1.04 (3H, d, 77.0Hz, 6'-H₃), 1.17-1.70 (2H, m, 4^*-H₂), 1.92-2.09 (IH, m, 3'-H), 2.15-2.25(1H, m, 8-H), 2.30 (3H, s, 15-H₃), 2.37 (IH, dd, 714.5,9.6Hz, 4-H), 2.76 (IH, br d, 714.5Hz, 4-H), 2.83 (3H, s, -SOCH₃), 3.42 (IH, dd, 78.7,3.1Hz, 6-H),3.55 (IH, d, 74.0Hz, 2'-H), 3.62-3.70 (IH, m, 16-H), 3.79-3.91 (2H, m, 5-H.16-H), 4.04-4.09 (IH, m, 7-H), 4.12-4.30 (2H, m, 9-H₂), 6.26 (IH, s, 2-H), 7.65 (IH, s, 4"-H), and 7.76-7.94 (4H, m, 4Ar-H); m/z (electrospray, +ve ion) 600 (MH+, 100%).

Examples in which R⁴ is the residue of an α-amino acid are prepared by acylation of examples in which R⁴ is hydrogen using a protected amino acid and standard peptide coupling conditions, followed by deprotection. The protected amino acid may suitably be N-Boc protected and the Boc group removed with trifluoroacetic acid. In this way was prepared Example 10:"

Example 10 - {3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylphenyl)oxazol-2-yl)-2-methyl prop-2-en-l-yl]tetrahydropyran-5R-yl}methyl

(2S,3S)-2-[yV-(phenyIalanyl)amino]-3-methyl-l-oxopent-l-ylsulfamate.

Biological Data

Determination of IC50 against isoleucyl t-RNA Synthetase.

Staph. aureus strains were grown to late stationary phase in shake flasks (240 φm) containing Nutrient Broth No2. For extraction of IRS, cells were harvested by centrifugation at 5000 x g and washed several times in cold phosphate buffered saline. Bacterial synthetases were extracted by sonication (MSE Soniprep [MSE Scientific Instruments, Crawley, U.K.] ; 6 x 15 second bursts at 15 microns, on ice) in the presence of lysostaphin (150 μg/ml) in the same buffer, followed by treatment with DNase (10 μ g/ml), overnight dialysis, and ultracentrifugation at 200,000 x g for lh. All enzymes were stored at -20°C in the presence of 30% glycerol.

IRS activity was assayed as charging of tRNA"^"6 with [U-1⁴C] -isoleucine (10) under conditions where counts were approximately proportional to time and enzyme concentration. Assay mixtures contained 30mM Tris, 2mM dithiothreitol (DTT), 10 mM MgCl2, 70 mM KCl, 1.56 mg/ml E. coli t-RNA (Boehringer Mannheim, Lewes, U.K.), 5mg/ml equine ATP, and [U-l⁴C]-isoleucine at 4.8 μM. I50 values, defined as the concentration of inhibitor resulting in 50% inhibition of [U-l⁴C]-isoleucine charging, were determined after pre-incubation of increasing concentrations of compound with IRS for 5 minutes, followed by addition of substrates and co-factors, and reaction for 10 minutes at 37°C. MIC values against a range of organisms, including E. coli, H. influenzae, Morax. catarrhalis, Ent. facalis, Staph. aureus. Strep, pneumoniae and Strep, pyogenes, were determined using standard procedures. The foregoing examples were generally found to be most active against several representative strains of Strep, pneumoniae, with MICs in the range 1 to 32μm/ml being obtained, as well as certain strains of H. influenzae (MICs 16-32μm/ml) and Morax. catarrhalis (MICs l-16μm ml).

Claims

1. A compound of formula (I):

(I) in which:

Rl is selected from:

(a) C(Me)=CHCOB! in which: βl is aryl, preferably phenyl, (Cι_ιo)alkyl, (C2-io)^alkenyl,

(C3.7)cycloalkyl, aryl(Cι_4)alkyl or heterocyclyl, preferably heteroaryl, each of which may be optionally substituted;

(b) C(Me)=CHCONHB² in which:

B² is optionally substituted (Ci.gjalkyl or aryl(Cι_4)alkyl; (c) C(Me)=CHB³ in which:

B³ is aryl, preferably phenyl, or a 5- or 6- membered heteroaryl ring having from 1 to 4 heteroatoms, preferably 1 to 3, most preferably 1 or 2, each selected from oxygen, sulphur or nitrogen and optionally substituted by (Cι_ιo)alkyl, ^-loJaH∞ny (C2- lθ)alkynyl, (C3_7)cycloalkyl, aryl(Cι _4)alkyl, aryl or heterocyclyl,

in which X and X2 is each independently selected from carbon, nitrogen, oxygen or sulphur, X3 is selected from carbon or nitrogen, optionally substituted by an aryl or a heteroaryl ring, X4 is selected from nitrogen, oxygen or sulphur and X5 is carbon, or Xi , X2, X4 and X5 is each nitrogen and X3 is carbon; R² is an optionally substituted (Ci.galkyl group; and n is 1 or 2.

2. A compound of formulaa (I) as claimed in claim 1 in which the heteroaryl group of B³ is selected from:

3. A compound of formula (I) as claimed in claim 2 in which the heteroaryl group is substituted by an optionally substituted phenyl group or a heteroaryl group selected from

4. A compound of formula (I) as claimed in claim 3 in which B³ is selected from :

5. A compound of formula (I) as claimed in any one of claims 1 to 4 in which the alkyl group in R² is substituted by one or two substituents selected from amino, (Cι_6)acylamino, [(α-amino)acyl]amino, (Cι _6)alkylamino, aryl(Cι _4)alkylamino, ureido, halogen, hydroxyl, (Cι_6)acyloxy and (Cι_6)alkylidene, carboxy, carbamoyl, aryl, heterocyclyl, hydroxy, thio, (Cι_6)alkylthio and guanidine

6. A compound of formula (I) as claimed in any one of claims 1 to 5 in which R² is a group of the formula:

R³CH(NHR⁴) in which:

R³ is hydrogen or a (Ci _5)alkyl group optionally substituted with a substituent selected from hydroxyl, carboxy, carbamoyl, amino, aryl, heterocyclyl, hydroxy, thio, (Cι _6)alkylthio and guanidino; and

R⁴ is H, (Ci _6)acyl, (Cι_6)alkyl, aryl(Cι galkyl or the residue of an α-amino acid, suitably a naturally occurring α-amino acid.

7. A compound of formula (I) as claimed in any one of claims 1 to 6 represented by the formula (IA):

(IA) in which: R⁴ is H, (Cι_g)acyl, (C ι .6)alkyl, aryl(Cι_4)alkyl, carbamoyl, or the residue an α-amino acid, suitably a naturally occurring α-amino acid.

8. A compound of formula (I) as claimed in any one of claims 1 to 7 in which n is 1.

9. A compound of formula (I) selected from:

{3R,4R-Dihydroxy-2S-[3(E)-(5-(3-methylisoxazol-5-yl)oxazol-2-yl)-2-methylprop-2-en- 1 -yl]tetrahydropyran-5R-yl } methyl (2S,3S)-2-amino-3-methyl- 1 -oxopent- 1 -ylsulfamate; {3R,4R-Dihydroxy-2S-[2-methyl-4-oxo-4-(4-propylthiophenyl)but-2-en-l- yl]tetτahydropyran-5R-yl Jmethyl (2S,3S)-2-amino-3-methyl- 1 -oxopent- 1 -ylsulfamate; {3R,4R-Dihydroxy-2S-[3(E)-(5-phenyloxazol-2-yl)-2-methylprop-2-en-l- yl]tetrahydropyran-5R-yl }methyl-(2S,3S)-2-amino-3-methyl-l -oxopent- 1 -yl sulfamate; {3R,4R-Dihydroxy-2S-[3(E)-(4-cyanofur-2-yl)oxazol-2-yl)-2-methylprop-2-en-l- yl]tetrahydropyran-5R-yl }methyl-(2S,3S)-2-amino-3-methyl-l -oxopent- 1 -yl sulfamate; { 3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylsulfonyl)phenyl)oxazol-2-yl)-2-methylprop-2- en- l-yl]tetrahydropyran-5R-yl) methyl (2S,3S)-2-amino-3-methyl-l -oxopent- 1- ylsulfamate;

{3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylthio)phenyl)oxazol-2-yl)-2-methylprop-2-en- l-yl]tetrahydropyran-5R-yl}methyl (2S,3S)-2-amino-3-methyl-l-oxopent-l -ylsulfamate;

{3R,4R-Dihydroxy-2S-[3(E)-(5-(4-chloropyridin-5-yl)oxazol-2-yl)-2-methylprop-2-en-l- yl]tetrahydropyran-5R-yl}methyl-(2S,3S)-2-amino-3-methyl-l-oxopent-l-yl sulfamate;

{ 3R,4R-Dihydroxy-2S-[3(E)-(5-(4-methylphenyl)oxazol-2-yl)-2-methylprop-2-en- 1 - yl]tetrahyQropyran-5R-yl}memyl-(2S,3S)-2-amino-3-methyl-l-oxopent-l-yl sulfamate; { 3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylsulfinyl)phenyl)oxazol-2-yl)-2-methylprop-2- en- l-yl]tetrahydropyran-5R-yl} methyl (2S,3S)-2-amino-3-methyl-l-oxopent-l- ylsulfamate; and

{3R,4R-Dihydroxy-2S-[3(E)-(5-(4-(methylphenyl)oxazol-2-yl)-2-methyl prop-2-en- 1 -yl] tetrahydropyran-5R-yl } methyl (2S,3S)-2-[/V-(phenylalanyl)amino]-3-methyl-l-oxopent-l-ylsulfamate.

10. A pharmaceutical composition comprising a compound of formula (I) as defined in claim 1.

11. A compound of formula (I) as defined in claim 1 for use in ti erapy.

12. A process for preparing a compound of formula (I) as defined in claim 1 which process comprises treating a compound of formula (II):

OZ¹

(II) in which Z and Z² which may be the same or different is each a hydroxyl protecting group, and n and R are as hereinbefore defined; with an activated derivative of a carboxylic acid of the formula: R²CO₂H in which R² is as hereinbefore defined and in which any optional substituents therein may be suitably be protected; in the presence of a suitable base, followed by the removal of any protecting group(s).