WO2000056713A1

WO2000056713A1 - Antiviral agents

Info

Publication number: WO2000056713A1
Application number: PCT/AU2000/000253
Authority: WO
Inventors: Sebastian Mario Marcuccio
Original assignee: Commonwealth Scientific And Industrial Research Organisation
Priority date: 1999-03-24
Filing date: 2000-03-24
Publication date: 2000-09-28
Also published as: AUPP942599A0

Abstract

This invention relates to compounds of formula (I) where R1 is hydrogen or C¿1? - C6 alkyl, and R?2¿ is -CH¿2?NHC(O)-R?3¿, -C(O)NHCH¿2-R?3 or -CH¿2?-NHCH2-R?3¿, where R3 is optionally substituted C¿7-11? alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, and pharmaceutically acceptable salts, bioprecursors and prodrugs thereof.

Description

ANTINIRAL AGENTS

The present invention relates to antiviral agents, in particular to substituted 3,4,5- trihydroxypiperidine compounds useful in the treatment of Hepatitis B virus and Hepatitis C virus. The invention also relates to the use of these compounds in the treatment of Hepatitis B virus and processes for their preparation.

Despite recent progress in relation to the treatment of viral infections in humans, viral infections still remains a major public health problem. Viruses of particular concern is the Hepatitis B virus (HBV) and Hepatitis C virus (HCV), which may cause acute or chronic infections in humans. Chronic HBV infection causes serious liver disease in humans and often results in cirrhosis and heptocellular carcinoma. Although there has been considerable research conducted in relation to HBV there is still no effective therapy for the successful management of HBV infection. HCV which has also been discovered more recently also has no effective therapy. The currently available therapies for viral infections, especially therapies for HBV, usually provide inadequate levels of efficiency, or are accompanied by deleterious side effects. The known therapies also provide inadequate levels of selectivity.

Much attention has been given to the identification of compounds which interfere directly with viral replication, and other compounds which act directly on viral enzymes. One such class of compounds is the nucleoside analogues which inhibit viral reverse transcriptase.

One disadvantage of directly targeting viruses for antiviral treatment relates to the ability of virus to transmutate, a process which can reduce the potency of an antiviral agent over a generally short period of time. Accordingly it would be advantageous to provide an antiviral agent which acts upon human enzymes involved in viral multiplication or infection, as a human enzyme would be less prone to mutation.

Two such compounds described in the prior art are n-butyl deoxynojirimycin and castanospermine.

Deoxynojirimycin Castanospermine

These compounds are inhibitors of human glucosidases, enzyme involved in the cleavage of sugars from viral proteins. Other related glucosidase inhibitors are described in US Patent 5,051,407 to Boshagen et al. In vitro studies have shown that some of these compounds have activity against a wide range of viruses, while others are only active against one or a few. Many compounds which have been shown to have antiviral activity in vitro have been found to have human toxicity and/or have been found to be inactive in vivo. Some possible reasons for this are lack of specificity in enzymes inhibited, metabolism of the compound in vivo, and poor transport to the site of action.

It is an object of the present invention to overcome or at least alleviate one or more of the disadvantages of the prior art.

Recently it has been shown that some glycosodase inhibitors which inhibit post- translation modifications of glycoproteins in the endoplasmic reticulum may selectively interfere with the proper folding and/or the formation of immature virus particles. HBV and HCV both contain glycosylated proteins with HCV being more heavily glycosylated and possibly more affected by glycosylation inhibitors. The compounds of this invention are glycosylation inhibitors and interfere with post-translational modifications of glycoproteins. Accordingly in a first aspect the present invention provides a compound of the formula (I)

where R¹ is hydrogen or C, - C₆ alkyl, and R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._n alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, and pharmaceutically acceptable salts, bioprecursors and prodrugs thereof, provided that when R³ is not substituted, one or more carbon atoms of the chain is replaced with a heteroatom selected from O, S or N.

The compounds of formula (I) have been shown to be surprisingly potent and selective against hepatitis B virus when tested according to the method of Korba and Gerin reported in Antiviral Research, 19, 55-70 (1992).

The compounds of formula (I) have also been found to have unexpectedly low mammalian toxicity.

Preferably R¹ is hydrogen.

Preferably R is -CH₂NHC(O)- R³ Preferred compounds of formula I include those wherein:

R' is H

R³ is selected from

-(CH₂)₃O(CH₂)₃CH₃,

-CH₂O(CH₂O)₂CH_3ι

-(CH₂)₉OH,

-(CH₂)₆OCH₂CH₃,

-(CH₂)₂CHOH(CH₂)₅CH₃, -(CH₂)₃CHOH(CH₂)₄CH₃,

-(CH₂)₂O(CH₂)₅CH₃,

-(CH₂O(CH₂)₆CH₃,

-CHOH(CH₂)₇CH₃,

-(CH₂)₃CHOH(CH₂)₆CH₃ , -(CH₂)₃CHOH(CH₂)₅CH₃,

-(CH₂)₂CHOH(CH₂)₆CH₃, and

-(CH₂)₂CHOH(CH₂)₃CH₃.

The term "C₇._π alkyl or alkylene chain" as used herein refers to a chain of 7 to 11 carbon atoms covalently bonded to one another. Preferably the chain is of 8 to 10 carbon atoms, more preferably 9 carbon atoms. The chain may include one or more double bonds in the case of alkylene chains. The carbon atoms may be bonded to hydrogen atoms or optional substituents through the spare valencies of the carbon atoms provided the largest chain of carbon atoms in the R³ group does not exceed 11. One or more of the carbon atoms of the chain may be optionally replaced with an O, S or N atom. Where a saturated carbon atom is replaced with N, the N atom may be bonded to hydrogen or an optional substituent through the spare valency.

The term "optionally substituted" as used herein in connection with the R³ substituent means that R³ may or may not be substituted with one or more non deleterious substituents, examples of which include C,_₆ alkyl, C,.₆ alkoxy, fluorine, amino, hydroxy, carboxy alkyl, aldehyde and C₃.₆ cycloalkyl. Preferably the substituents are selected from those which assist in hydrogen bonding within the glucosidase aglycone attachment site, or which improve or alter the solubility of the compound to suit specific formulation or delivery requirements. The term "optionally substituted" also indicates that two or more of the carbon atoms or nitrogen atoms if present, may be linked together to form a 5 or 6 membered aromatic or aliphatic ring, which may be carbocyclic or heterocyclic, and which may be optionally substituted.

Examples of suitable aromatic or aliphatic rings include benzene, pyridine, cyclopentane, cyclohexane, cyclohexene and 1,2-pyran.

Examples of suitable R³ groups include C₇._n alkyl, C₇._M alkylene, (CH₂)_mX(CH₂)_nH, -[(CH₂)_pX]_qCH₃ and -[(CH₂)-X]_s(CH₂)_tH where each X is independently selected from O, S and NH; m and n are independently 0 to 10, provided m + n is 6 to 10; each p is independently 1 to 5 and q is 1 to 5, provided q + ∑(pq) is 6 to 10; and each r is independently 1 to 3, s is 1 to 4; and t is 1 to 5, provided that s + t + ∑(rs) is 7 to 11; each of which groups may be optionally substituted.

As used herein the claims and the description the symbol "∑" means "the sum of", such that ∑(pq) =the sum of the products of p.q and ∑(rs) =the sum of the products of r.s.

If the R³ group is substituted, it is preferably substituted with hydroxy.

The present invention further provides a method for the treatment or prophylaxis of HBV or HBC infection comprising administering an effective amount of a compound of formula (I)

where R¹ is hydrogen or C, - C₆ alkyl, and

R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._n alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, and a pharmaceutically acceptable salt, bioprecursor or prodrug thereof.

The invention further provides the use of a compound of formula (I)

where R¹ is hydrogen or C, - C₆ alkyl, and

R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._n alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof, in the manufacture of a medicament for the treatment of HBV or HBC infection in humans. Preferred compounds of formula (I) include 1-nonanoylaminomethyl-l-deoxynorjirimycin, 1-decanoylaminomethyl-l-deoxynorjirimycin, and 1-undecanoylaminomethyl-l- deoxy norj ir imy cin .

The salts of the compound of formula (I) are preferably pharmaceutically acceptable, but it will be appreciated that non-pharmaceutically acceptable salts also fall within the scope of the present invention, since these are useful as intermediates in the preparation of pharmaceutically acceptable salts. The pharmaceutically acceptable salts may include conventional non-toxic salts or quaternary ammonium salts of these compounds, which may be formed, e.g. from organic or inorganic acids or bases. Examples of such acid addition salts mclude, but are not limited to, those formed with pharmaceutically acceptable acids such as acetic, propionic, citric, lactic, methanesulphonic, toluenesulphonic, benzenesulphonic, salicylic, ascorbic, hydrochloric, orthophosphoric, sulphuric and hydrobromic acids. Base salts includes, but is not limited to, those formed with pharmaceutically acceptable cations, such as sodium, potassium, lithium, calcium, magnesium, ammonium and alkylammonium. Also, basic nitrogen- containing groups may be quarternized with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl and diethyl sulfate; and others.

The compounds of the invention may be in crystalline form or as solvates (e.g. hydrates) and it is intended that both forms are within the scope of the present invention. Methods of solvation are generally known within the art.

Pharmaceutically acceptable derivatives may include any pharmaceutically acceptable salt, hydrate or any other compound which, upon administration to a subject, is capable of providing (directly or indirectly) a compound of formula (I) or an antivirally active metabolite or residue thereof.

Any compound that is a prodrug or bioprecursor of a compound of formula (I) is within the scope and spirit of the invention. The terms "pro-drug" and "bioprecursor" are used in their broadest sense and encompasses all those derivatives that are converted in vivo to the compounds of the invention. Such derivatives would readily occur to those skilled in the art, and include, for example, chlorides and compounds where a free hydroxy group is converted into an ester derivative. Examples of ester derivatives include alkyl esters, oxylates, carbonates, phosphate esters, sulphate esters, and those formed from amino acids, such as valine.

It will be appreciated that some derivatives of the compound of formula (I) may have additional asymmetric centres and therefore are capable of existing in more than one stereoisomeric form. The invention extends to each of these forms individually and to mixtures thereof, including racemates. The isomers may be separated conventionally by chromatographic methods including chiral chromatography, enzymatic resolution, or using a resolving agent. Alternatively, the individual isomers may be prepared by asymmetric synthesis using chiral intermediates.

While it is possible that for use in therapy a compound of the invention may be administered as the new chemical, it is preferable to present the active ingredient as a pharmaceutical composition. Accordingly, yet another aspect of the invention provides a pharmaceutical composition comprising a compound of formula (I) as defined above or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof and a pharmaceutically acceptable carrier or diluent.

The carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

Pharmaceutical formulations include those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), vaginal or parenteral (including intramuscular, subcutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation. The compounds of the invention, together with a conventional adjuvant, carrier, or diluent, may thus be placed into the form of pharmaceutical compositions and unit dosages thereof, and in such form may be employed as solids, such as tablets or filled capsules, or liquids such as solutions, suspensions, emulsions, elixirs, or capsules filled with the same, all for oral use, in the form of suppositories for rectal administration; or in the form of sterile injectable solutions for parenteral (including subcutaneous) use. Such pharmaceutical compositions and unit dosage forms thereof may comprise conventional ingredients in conventional proportions, with or without additional active compounds or principles, and such unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. Formulations containing ten (10) milligrams of active ingredient or, more broadly, 0J to one hundred (100) milligrams, per tablet, are accordingly suitable representative unit dosage forms.

The compounds of the present invention can be administered in a wide variety of oral and parenteral dosage forms. It will be obvious to those skilled in the art that the following dosage forms may comprise, as the active component, either a compound of the invention or a pharmaceutically acceptable salt of a compound of the invention.

For preparing pharmaceutical compositions from the compounds of the present mvention, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispersible granules. A solid carrier can be one or more substances which may also act as diluents, flavouring agents, solubilizers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material.

In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component.

In tablets, the active component is mixed with the carrier having the necessary binding capacity in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain from five or ten to about seventy percent of the active compound. Suitable carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term "preparation" is intended to include the formulation of the active compound with encapsulating material as carrier providing a capsule in which the active component, with or without carriers, is surrounded by a carrier, which is thus in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges can be used as solid forms suitable for oral administration.

For preparing suppositories, a low melting wax, such as admixture of fatty acid glycerides or cocoa butter, is first melted and the active component is dispersed homogeneously therein, as by stirring. The molten homogenous mixture is then poured into convenient sized moulds, allowed to cool, and thereby to solidify.

Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.

Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water-propylene glycol solutions. For example, parenteral injection liquid preparations can be formulated as solutions in aqueous polyethylene glycol solution.

The compounds according to the present invention may thus be formulated for parenteral administration (e.g. by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.

Aqueous solutions suitable for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours, stabilizing and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, or other well known suspending agents.

Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. These preparations may contain, in addition to the active component, colorants, flavours, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents, and the like.

For topical administration to the epidermis the compounds according to the invention may be formulated as ointments, creams or lotions, or as a transdermal patch. Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilising agents, dispersing agents, suspending agents, thickening agents, or colouring agents.

Formulations suitable for topical administration in the mouth include lozenges comprising active agent in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier. Solutions or suspensions are applied directly to the nasal cavity by conventional means, for example with a dropper, pipette or spray. The formulations may be provided in single or multidose form. In the latter case of a dropper or pipette, this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray, this may be achieved for example by means of a metering atomising spray pump.

Administration to the respiratory tract may also be achieved by means of an aerosol formulation in which the active ingredient is provided in a pressurised pack with a suitable propellant such as a chlorofluorocarbon (CFC) for example dichlorodifluoromethane, trichlorofluoromethane, or dichlorotetrafluoroethane, carbon dioxide, or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by provision of a metered valve.

Alternatively the active ingredients may be provided in the form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP). Conveniently the powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form for example in capsules or cartridges of, e.g. gelatin, or blister packs from which the powder may be administered by means of an inhaler.

In formulations intended for administration to the respiratory tract, including intranasal formulations, the compound will generally have a small particle size for example of the order of 5 microns or less. Such a particle size may be obtained by means known in the art, for example by micronization.

When desired, formulations adapted to give sustained release of the active ingredient may be employed. The pharmaceutical preparations are preferably in unit dosage forms. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form.

Tablets or capsules for oral administration and liquids for intravenous administration are preferred compositions.

The compounds of the present invention may also be useful in combination with known anti-viral or anti-retroviral agents, or other pharmaceuticals used in the treatment of oral infections. Representative examples of these additional pharmaceuticals include immunomodulators, immunostimulents, and antibiotics. Exemplary anti- viral agents include AZT, 3TC, (-)-FTC, acyclovir, famcyclovir, penciclovir, ddl, ddC, ganciclovir, saquanivir, moviride, adefovir dipivoxil, BMS-200475, emtricitabine ((-)-FTC), B-L- Fd4C, clevudine (L-FMAU), DAPD, nabi-3700.001 and other non-nucleotide reverse transcriptase (RT) inhibitors and protease inhibitors. Exemplary immunomodulators and immunostimulents include various inter lukins, sidachomes, antibody preparations, blood transfusions and cell transfusions. Exemplary antibiotics include antifungal agents, and antibacterial agents.

It is particularly preferred to use the compounds of formula (I) in conjunction with a nucleoside anti-viral agent which inhibits reverse transcriptase as the two different modes of action provide an unexpectedly superior anti-viral treatment. This appears to be due to a synergistic effect between the compound of formula (I) and the nucleoside anti-viral agent.

Accordingly in yet another aspect of the present invention there is provided a pharmaceutical composition comprising a compound of formula (I) as defined above, or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof, and a nucleoside anti- viral agent.

Examples of suitable nucleoside anti-viral agents include those described above. Preferably the nucleoside anti-viral agent is 3TC, adefovir dipivoxil, BMS-200475, emtricitabine ((-)-FTC), B-L-Fd4C, clevudine (L-FMAU), DAPD and nabi-3700.001.

Without wishing to be limited to theory it is believed that the alpha configuration of the compounds of formula (I) improves the selectivity of the compounds for glycosidases involved in the cleavage of sugars from proteins associated with hepatitis B and C viruses, these glycosidases being alpha specific. It is also believed that the length of the R² chain is important and that bonding effects and substituents along the chain can be used to improve potency and give improved chemical and pharmaceutical properties.

The compounds according to the present invention may be prepared in an analogous manner to methods described in DE 3024901 (Al) to Bayer, the entire contents of which is incorporated herein by reference.

Preferably preparation of the compound of formula (I) proceeds via the known intermediate l,2-O-isopropylidene-α-D-glucofuranosidurono-5-urose-6,3- lactone.monohydrate. This intermediate may be prepared using known procedures, however it has been found that surprisingly good yields of this intermediate may be achieved by oxidation of l,2-O-isopropylidene-α-D-glucofuranosidurono-6,3-lactone with a ruthenium catalyst, such as ruthenium (III) chloride. Accordingly the use of a ruthenium catalyst in the preparation of the monohydrate intermediate represents a further aspect of the present invention. Other suitable ruthenium catalysts include Rh III bromide, Rh III iodide, Rh (III) acetylacetonate, RhO₂ and RhO_2xH₂O.

One route to the compounds of formula (I) is shown in reaction scheme 1 below: Scheme 1

The invention will now be described with reference to the following examples which illustrate some preferred aspects of the present invention. However it is to be understood that the particularity of the following description is not to supersede the generality of the preceding description of the invention.

PREPARATION EXAMPLES

Example 1

(a) 1 ,2-O-Isopropylidene-α-D-glucofuranosidurono-5-urose-6,3-lactone. monohydrate To a solution of l,2-O-isopropylidene-α-D-glucofuranosidurono-6,3-lactone(130g.) in acetone(630ml.) was added 70% tert-butyl hydroperoxide(lmL) then powdered ruthenium trichloride(1.3g.). The vigorously stirred mixture was maintained at a temperature of 22-28 °C with external cooling while 70% tert-butyl hydroperoxide(350ml.) was added over 1.5 hours. The mixture was stirred for 1 hour at 25°C then solvent removed in vacuo. The residue was taken up in warm ethyl acetate, filtered, then passed rapidly through a column of silica gel(300g., 70- 230 mesh) eluting with ethyl acetate. Product crystallised from ethyl acetate as white crystals of the monohydrate, 121g.87% .

(b) l,2-O-Isopropylidene-α-D-glucofuranosidurono-5-urose-6,3-lactone methoxime

A stirred mixture of l,2-O-isopropylidene-α-D-glucofuranosidurono-5-urose-6,3- lactone monohydrate (121g.), pyridine(42ml.), methoxyamine hydrochloride(43.5g.) and benzene(1.5L.) was slowly heated to reflux, under an atmosphere of nitrogen, over 1 hour. The mixture was refluxed, under water entrainment, until no more water separated, then cooled and the solvent removed in vacuo. The residue was extracted with ethyl acetate and the extract washed with water, dried over anhydrous sodium sulphate, and evaporated. The residue was subjected to short-path distillation at 140°C/10^"6 torr to give a light yellow oil. 108g.85% (c) 5-Amino-5-deoxy-l ,2-O-isopropylidene- -D-glucofuranose

To a solution of l,2-O-isopropylidene-α-D-glucofuranosidurono-5-urose-6,3- lactone methoxime(79g.) in anhydrous tetrahydrofuran(600ml.), stirred at 0°C under an argon atmosphere, was added a 1M solution of diborane in anhydrous tetrahydrofuran (1050ml.) over 30 min. The stirred mixture was allowed to come to room temperature and stirred for 17 hours. The reaction mixture was cooled to 0°C and anhydrous methanol (600ml.) was added dropwise with cooling. The mixture was stirred at 20 °C for 17 hours and volatiles were removed in vacuo. The residue was treated 4 times with 200ml. aliquots of anhydrous methanol, stirring for 2 hours then evaporating to dryness. The residue was dissolved in water and percolated through a column of C_lg reversed phase silica gel eluting with 5% methanol/ water. Evaporation and lyophilisation gave the product as a white foam. 60.5g. 85%.

(d) Deoxynorjirimycin-1-sulphonic acid

5-Amino-5-deoxy-l,2-O-isopropylidene-α-D-glucofuranose(10g.) was stirred at 35 °C in a sealed container with 100ml. of a solution of sulphur dioxide in water, saturated at 0°C, for three days. After removal of excess sulphur dioxide in vacuo, methanol (200ml.) was added and the slurry cooled in ice. Filtration gave the product as a white powder. 7.5g.

(e) 1-α-Cyano-l-deoxynojirimycin

To a stirred mixture of barium hydroxide octahydrate (13.2g.) and water (40ml.) at 20°C, under an atmosphere of argon, was added 1-doxynorjirimycin-l-sulphonic acid (10.2g.) then, after 1 minute, powdered sodium cyanide (2.8g.). Hydrochloric acid (8.3ml. of 7.5M) was added dropwise over 10 minutes and the reaction mixture stirred a further 4 hours. The mixture was filtered and the filtrate evaporated to dryness. The residue was extracted with 1: 1 methanolacetonitrile and the solvent was evaporated to give the product as a white powder. 7.7g.

(f) 1 - Aminomethy 1- 1 -deoxy noj irimy cin

1- -Cyano-l-deoxynojirimycin (8.3g.) was dissolved in water (140ml. )and Raney nickel (34g. wet weight) was added. The mixture was hydrogenated in a Parr shaker at 3.5 bar for 6 hours. The mixture was filtered and lyophilised to give the product as a pale yellow solid. 7.9g.

(g) 1-Nonanoylaminomethyl-l-desoxynorjirimycin

To a solution of 1-aminomethyl-l-desoxynorjirimycin (400mg.) in anhydrous methanol (50ml.) at 20°C was added nonanoic anhydride (500mg.) and the mixture stirred at room temperature for 48 hours. Volatiles were removed in vacuo at room temperature and the residue dissolved in water (15ml.) This solution was passed through a column of Dowex lX2[OH^" form] (lOg.) eluting with water. Fractions containing product were combined and lyophilised to give the product as a white powder.

nmr: Η chemical shift (ppm) - amide 7.55(t), methyl 0.85(t).

Example 2

1 -Decanoylaminomethyl- 1 -desoxynorj irimycin

To a solution of 1-aminomethyl-l-desoxynorjirimycin (4009mg.) in anhydrous methanol (50ml.) at 20°C was added decanoic anhydride (550mg.) and the mixture stirred at room temperature for 48 hours. Volatiles were removed in vacuo at room temperature and the residue dissolved in water (15ml.). This solution was passed through a column of Dowex lX2[OH^" form] (lOg.) eluting with water. Fractions containing product were combined and lyophilised to give the product as a white powder. nmr: Η chemical shift (ppm) - amide 7.60(t), methyl 0.85(t).

Example 3

1 -Undecanoy laminomethy 1- 1 -desoxy norj ir imy cin

To a solution of 1-aminomethyl-l -desoxy norj irimycin (400mg.) in anhydrous methanol (50ml.) at 20 °C was added undecanoic anhydride (600mg.) and the mixture stirred at room temperature for 48 hours. Volatiles were removed in vacuo at room temperature and the residue dissolved in water (15ml.). This solution was passed through a column of Dowex lX2[OH^" form] (lOg.) eluting with water. Fractions containing product were combined and lyophilised to give the product as a white powder.

nmr: chemical shift (ppm) - amide 7.55(t), methyl 0.85(t).

Example 4

Prepared from [2R-(2α,3α,4β,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 5- oxadecanoic acid using the method of Example 1 and purified by flash chromatography 20/80 methanol/dichloromethane. Yield 173mg (26.8%).

Η nmr (DMSO-d₆) δ 0.86 (t, J=6 Hz, 3H), 1.20 - 1.32 (m, 4H), 1.47 (p, J=7 Hz, 2H), 1.69 (p, J=7 Hz, 2H), 2.77 - 3.02 (m, 4H), 3.14 - 3.41 (m, 9 est.), 3.55 - 3.68 (m, IH), 4.32 (t, IH), 4.32 (t, J=5 Hz, IH), 4.60 (d, J=5 Hz, IH), 4.72 (d, J=4 Hz, IH), 4.82 (d, J=4 Hz, IH), 7.52 (t, J=5 Hz, IH). Example 5

Prepared from [2R-(2αJα,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 4-heptylbenzoic acid using the method of Example 1 and crystallised from methanol. Yield 37 mg (9.0 %).

Η nmr (DMSO-d₆) δ 0.86 (t, J=6 Hz, 3H), 1.15 - 1.36 (m, 8H), 1.47 - 1.67 (m, 2H), 2.62 (t, J=7 Hz, 2H), 2.80 - 2.95 (m, 2H), 3.10 - 337 (m, 5 est), 3.37 - 3.50 (m, 2H), 3.58 - 3.70 (m, IH), 4.32 (t, J=5 Hz, IH), 4.63 (d, J=5 Hz, IH), 4.75 (d, J=4 Hz, IH), 4.90 (d, J=4 Hz, IH), 7.27 (d, J=8 Hz, 2H), 7.74 (d, J=8 Hz, 2H), 8.05 (t, J=6 Hz, IH).

Example 6

Prepared from [2R-(2αJ ,4β,5 ,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and

3,6,9-trioxadecanoic acid using the method of Example 1 and purified by preparative hplc

10/90 acetonitrile/water 10 ml/min. Yield 61 mg (13.3%).

'H nmr (DMSO-d₆) δ 2.84 - 3.10 (m, 2 est), 3.15 - 3.76 (m, 19 est), 3.88 (s, 2H), 438 (t,

J=4 Hz, IH), 4.63 (d, J=5 Hz, IH), 4.76 (d, J=4 Hz, - IH), 4.90 (d, J=4 Hz, IH), 7.40 - 7.56 (m, IH). Example 7

The compound of example 1 (102 mg, 0J9 mmole) was suspended in THF (dry, 10 ml), in a flask under a nitrogen atmosphere and immersed in an ice/water bath.

10 Borane-tetrahydrofuran (IM, 3 ml, 3 mmole) was added slowly by syringe. After 30 min the cooling was removed and the mixture was allowed to stir at room temperature for 64 hrs. Methanol (9 ml) was added dropwise and stirred for a further 30 min. The solvents were removed by rotary evaporation. Methanol (9 ml) was added to the residue and removed. This last step was repeated four more times. The product was purified by flash

15 chromatography 20/80 methanol/chloroform. Yield 14 mg (14.3%).

'H nmr (DMSO-d₆) δ 0.87 (t, J=6 Hz, 3H), 1.05 - 1.38 (m, 14H), 1.49 - 1.70 (m, 2H), 2.20 - 2.47 (m, 2H), 2.56 - 2.80 (m, 3H), 2.83 - 3.01 (m, IH), 3.03 - 3.28 (m, 2H), 3.34 - 3.63 (m, 4H), 4.35 - 4.54 (m, IH), 4.64 (d, j= 5Hz, IH), 4.78 (t, j=4 Hz, IH), 4.95 (d, J=3 Hz, IH), 5.02 (d, j=4 Hz, IH). 0

Example 8

Prepared from

[2R-(2 ,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 30 10-hydroxydecanoic acid using the method of Example 1 at 40 °C and purified by flash chromatography 25/75 methanol/dichloromethane. Yield 105 mg (27.9 %). 'H nmr (DMSO-d₆) δ 1.16 - 132 (m, 10H), 135 - 1.58 (m, 4H), 2.07 (t, J=7 Hz, 2H), 2.69 - 3.02 (m, 2H), 3.10 - 3.30 (m, 4H), 3.35 (t, J=6 Hz, 2H), 3.56 - 3.69 (m, IH), 4.28 - 4.40 (m, 2H), 4.62 (d, J=5 Hz, IH), 4.74 (d, J=4 Hz, IH), 4.84 (d, J=4 Hz, IH), 7.53 (t, J=5 Hz, IH).

Example 9

Prepared from

[2R-(2 ,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 8-oxadecanoic acid using the method of Example 1 at 40 °C and purified by flash chromatography 20/80 methanol/dichloromethane. Yield 96 mg (26.5%).

Η nmr (DMSO-d₆) δ 1.08 (t, J=7 Hz, 3H), 1.19 - 1.32 (m, 4H), 1.38 - 1.56 (m, 4H), 2.06 (t, J=7 Hz, 2H), 2.76 - 3.01 (m, 2H), 3.09 - 3.45 (m, 9 est), 3.39 (t, J=7 Hz, 2H), 3.55 -3.69 (m, IH), 4.23 - 4.39 (m, IH), 4.55 - 4.92 (m, 3H), 7.47 - 7.59 (m, IH).

Example 10

Prepared from

[2R-(2 ,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and g-decanolactone using the method of Example 1 without EEDQ, at 40 °C and purified by flash chromatography 30/70 methanol/dichloromethane. Yield 26 mg (6.0 %).

'H nmr (DMSO-d6) δ 0.85 (t, J=7 Hz, 3H), 1.15 - 1.40 (m, 10H), 1.40 - 1.69 (m, 2H), 2.07 2.21 (m, 2H), 2.76 - 3.01 (m, 2H), 3.07 - 3.45 (m, 8H), 3.54 - 3.69 (m, IH), 4.35 (t, J=5 Hz, IH), 4.41 (br s, IH), 4.63 (d, J=5 Hz, IH), 4.75 (d, J=4 Hz, IH), 4.83 (d, J=4 Hz, IH), 7.58 (t, J=5 Hz, = IH).

Example 11

Prepared from

[2R-(2α,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and d-decanolactone using the method of Example 1 without EEDQ, at 40 °C and purified by flash chromatography 30/70 methanol/dichloromethane for 250 ml then changed to 40/60 methanol/dichloromethane. Yield 135 mg (35.8 %).

Η nmr (DMSO-d6) δ 0.85 (t, J=7 Hz, 3H), 1.13 - 1.40 (m, 10H), 1.40 - 1.69 (m, 2H), 2.05 (t, J=7 Hz, 2H), 2.76 - 3.01 (m, 2H), 3.06 - 3.46 (m, 5H), 3.16 (d, J=5 Hz, 2H), 3.55 - 3.69 (m, IH), 4.07 - 4.20 (m, IH), 4.22 - 4.3= 9 (m, 2H), 4.63 (d, J=5 Hz, IH), 4.76 (d, J=4 Hz, IH), 4.83 (d, J=4 Hz, IH), 7.56 (t, J=5 Hz, IH).

Example 12

Prepared from [2R-(2α,3 ,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 4-oxadecanoic acid using the method of Example 1 at 50 °C and then purified by flash chromatography 5/95 methanol/dichloromethane. Yield 52.5 mg (14.5 %). Η nmr (DMSO-d₆) δ 0.85 (t, J=7 Hz, 3H), 1.15 - 1.34 (m, 6H), 1.37 - 1.53 (m, 2H), 2.31 (t, J=7 Hz, 2H), 2.45 - 2.60 (m, 2 est.), 2.77 - 3.00 (m, 2H), 3.08 - 3.44 (m, 6H, est), 3.48 - 3.67 (m, 2H), 3.54 (t, J=7 Hz, 2H), 4.22 - 4.35 (m, IH), 4.61 (d, J=4 Hz, IH), 4.70 - 4.77 (m, IH), 4.78 - 4.8= 6(m, IH), 7.55 - 7.65 (m, IH).

Example 13

Prepared from

[2R-(2 ,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and 3 -oxadecanoic acid using the method of Example 1 at 40 °C and then purified by flash chromatography 5/95 methanol/dichloromethane. Yield 29 mg (8.0 %). ^]H nmr (DMSO-d₆) δ 0.86 (t, J=7 Hz, 3H), 1.20 - 1.35 (m, 8H), 1.43 - 1.61 (m, 2H), 2.82 - 3.05 (m, 2H), 3.11 - 3.48 (m, 4 est.), 3.16 (d, J=5 Hz, 2H), 3.41 (t, J=7 Hz, 2H), 3.48 - 3.61 (m, IH), 3.81 (s, 2H), 4.03 - 4.20 (m, IH), 4.35 (t, J=5 Hz, IH), 4.61 (d, J=5 Hz, IH), 4.72 ■ 4.80 (m, IH), 4.90 (d, J=4 Hz, IH), 7.42 (t, J=5 Hz, IH).

Example 14

Prepared from

[2R-(2α,3α,4β,5α,6β)]-2-(aminomethyl)-6-(hydroxymethyl)-3,4,5-piperidinetriol and d 2-hydroxy decanoic acid using the method of Example 1 at 50 °C and then purified by flash chromatography 10/90 ethanol/dichloromethane. Yield 24 mg (26.4 %). 'H nmr (DMSO-d₆) δ 0.86 (t, J=7 Hz, 3H), 1.18 - 1.47 (m, 12H), 1.59 - 1.89 (m, 2H), 2.88 - 3.03 (m, 2H), **, 3.52 -3.64 (m, 2H), **, 4.63 (d, J=5 Hz, IH), 4.79 (d, J=4 Hz, IH), **, **.

Example 15

Prepared from corresponding amine and acid 'H chemical shift (ppm) - amide 7.60(f), methyl 0.85(t).

Example 16

Prepared from corresponding amine and acid 'H chemical shift (ppm) amide 7.55(f), methyl 0.85(f) Example 17

Prepared from corresponding amine and acid ^!H chemical shift (ppm) - amide 7.55(t), methyl 0.85(t).

Example 18

Prepared from corresponding amine and acid Η chemical shift (ppm) - amide 7.60(t), methyl 0.85(t).

Example 19 - Antiviral activity

The anti-HBN activity (El₅₀ and SI₅₀) of some compounds according to the invention was tested according to the method of Korba and Gerin as reported in Antiviral Research, 19, 55-70 (1992).

The results are shown below in Table 1.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any two or more of said steps or features.

Claims

THE CLAIMS:

1. A compound of the formula (I)

where R¹ is hydrogen or C, - C₆ alkyl, and

R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._π alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, and pharmaceutically acceptable salts, bioprecursors and prodrugs thereof, provided that when R³ is not substituted, one or more carbon atoms of the chain is replaced with a heteroatom selected from O, S or N.

2. A compound of claim 1 wherein R¹ is hydrogen.

3. A compound of claim 1 wherein R² is -CH₂NHC(O)-R³.

4. A compound of claim 1 wherein the length of the alkyl or alkylene chain, R₃, is between 8 and 10 carbon atoms.

5. A compound of claim 1 wherein the length of the chain, R³, is 9 carbon atoms.

6. A compound according to claim 1 wherein one or more of the carbon atoms in the chain, R3, is replaced with a heteroatom selected from O, S or N.

7. A compound according to claim 1 wherein R³ includes one or more substituents which assists in hydrogen bonding with the glucosidase aglycone attachment site.

8. A compound according to claim 1 wherein R³ includes a substituent selected to improve or alter the solubility of the compound to suit formulation or delivery requirements.

9. A compound according to claim 1 wherein R³ is substituted with hydroxy.

10. A compound of claim 1 wherein R³ is a group selected from C₇._n alkyl, C_7.n alkylene, -(CH₂)_mX(CH₂)_nH, -[(CH₂)_pX]_qCH₃ and -[(CH₂)-X]_s(CH₂)_tH where each X is independently selected from O, S and NH; m and n are independently 0 to 10, provided m + n is 6 to 10; each p is independently 1 to 5 and q is 1 to 5, provided q + ∑(ps) is 6 to 10; and each r is independently 1 to 3, s is 1 to 4; and t is 1 to 5, provided that s + t + ∑(rs) r is 7 to 11; each of which groups may be optionally substituted.

11. A method for the treatment or prophylaxis of HBV or HCV infection comprising administering an effective amount of a compound of formula (I)

where R¹ is hydrogen or C, - C₆ alkyl, and

R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._π alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof.

12. A method according to claim 11 wherein the compound of formula (I) is selected from the group consisting of 1-nonanoylaminomethyl-l-deoxynorjirimycin, 1- decanoylaminomethyl- 1 -deoxynorj irimycin, and 1 -undecanoylaminomethyl- 1 - deoxynorj irimycin .

13. The use of a compound of formula (I)

where R¹ is hydrogen or C_x - C₆ alkyl, and

R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R\ where R³ is optionally substituted C₇._n alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof, in the manufacture of a medicament for the treatment of HBV or HCV infection in humans.

14. A pharmaceutical composition comprising a compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt, bioprecursor or prodrug thereof and a pharmaceutically acceptable carrier or diluent.

15. A process for the preparation of 1,2-O-iodopropylidene-α-D-glucofuranosidurono- 5-urose-6,3-lactone monohydrate by oxidation of 1 ,2-O-isopropylidine-α-D- glucofuranosidurono-6,3-lactone with a ruthenium catalyst.

16. A compound of formula I according to claim 1 wherein

R' is H

R³ is selected from

10

-(CH₂)₃O(CH₂)₃CH₃,

-CH₂O(CH₂O)₂CH₃

-(CH₂)₉OH,

-(CH₂)₆OCH₂CH₃, 15 -(CH₂)₂CHOH(CH₂)₅CH₃,

-(CH₂)₃CHOH(CH₂)₄CH₃,

-(CH₂)₂O(CH₂)₅CH₃,

-(CH₂O(CH₂)₆CH₃,

-CHOH(CH₂)₇CH₃, 20 -(CH₂)₃CHOH(CH₂)₆CH₃,

-(CH₂)₃CHOH(CH₂)₅CH₃,

-(CH₂)₂CHOH(CH₂)₆CH₃, and

-(CH₂)₂CHOH(CH₂)₃CH₃.

25 17. A method according to claim 11 wherein the compound of formula (I) is administered together with a known anti-viral or anti-retroviral agent, or other pharmaceutical used in the treatment of oral infections.

30

18. A pharmaceutical composition comprising a compound of formula (I)

where R is hydrogen or C_λ - C₆ alkyl, and R² is -CH₂NHC(O)-R³, -C(O)NHCH₂-R³ or -CH₂-NHCH₂-R³, where R³ is optionally substituted C₇._n alkyl or alkylene chain where one or more carbon atoms of the chain is optionally replaced with a heteroatom selected from O, S or N, wherein the length of the chain (excluding any terminal hydrogen atoms) is between 7 and 11 atoms, and pharmaceutically acceptable salts, bioprecursors and prodrugs thereof in combination with a known anti- viral or anti-retroviral agent, or other pharmaceutical used in the treatment of oral infections.

19. Use according to claim 13 wherein the medicament further includes a known antiviral or anti-retroviral agent, or other pharmaceutical used in the treatment of oral infections.