CA1333392C - Antiviral compounds - Google Patents

Abstract

A compound of formula (I):

(I)

Description

- ~ 1 333392 The present invention relates to certain nucleoside derivatives having activity against adenoviruses.

This Application is a divisional of Canadian Patent Application, Serial No.
575,197, filed August 19, 1988.

Adenoviruses were first isolated from man in 1953 and at least 41 differen~
serotypes representing 6 subgenera have now been identified, Adenoviruses are responsible, for example, for 5% of acute respiratory infections in children under 4 years of age and are found in 10% of respiratory diseases in this age group requiring hospitalisation. Such conditions are generally associated with pharyngitis, coughing and con~unctivitis. Very often laryngotracheobronchitis occurs which develops into pneumonia in young children, and in fact, 10~ of childhood pneumonias are due to adenovirus infection and are often fatal in children under 2 years of age.

In the older population adenoviruses are often responsible for pharyngocon~unctival fever and acute respiratory disease in institutionalised persons where it has been known to have a fatal outcome, The viruses are often associated with pertussis syndrome, haemorrhagic cystltis, meningitis, diarrhoea and epidemic keratocon~unctivitis. The latter condition is characterised by rapid conjunctival involvement with pain, photophobia, lymphadenopathy and subsequent keratitis. The syndrome may last for several weeks but the corneal opacity may endure for several years. The patient is therefore disabled to varying degrees over a period of time. It has been shown that adenovirus type 8 ls the major etiologic agent in this particulsr aspect of adenovirus disease. Adenovirus disease is particularly severe in children with severe combined immunodeficiency disease (SCID) and in immunocompromised hosts. Adenoviruses are recognised also as increasingly more common in patients with Acquired Immune Deficiency Syndrome (AIDS) and in bone marrow transplant recipients. There has hitherto been no useful antiviral compound that is effective in the treatment of adenoviral infections and there is also no adequate vaccine.

We have now discovered that a compound of fonmula (I) below has potent activity against adenoviruses particularly those of type 8.

~, A

The present invention accordingly provides compounds of formula (I) Hl`l~ ~
I (I) F

wherein R represents a chlorine atom and physiologically acceptable salts and esters thereof. T~le compound, salts and esters are useful in the treatment or prophylaxis of an adenovirus infection. Such compound, salts and esters are hereafter referred to as co~pounds according to this invention.
This disclosure also describes related compounds including compounds in which R
is an iodine atam.
Particularly preferred compounds by virtue of their especially potent activity against adenoviruses are:-1. 5-iodo-l-(2,3-dideoxy-3-fluoro7~-D-erythro-pentofuranosyl)uracil.
2. 5-chloro-1-(2,3-dideoxy-3-fluoro ~-D-erythro-pentofuranosyl)uracil.
A related compound is:

3. 2',3'-dideoxy-3'-fluorothymidine.
Compound No. 3 referred to above has particularly high anti-adenovirus activity especially against serotypes 5 and 8.
In a further aspect of the present invention, there is provided the use of a compound according to the invention in the manufacture of a mp~icA
ment for the treatment or prophylaxis of adenovirus infections.

A

1 33339~
_ - 3 -The present invention further provides a method for the treatment or prophylaxis of an adenovirus infection in a human sub;ect which comprises administering to the said human subject an effective amount of a compound according to the invention-.

Examples of adenovirus infections which may be treated or prevented inaccordance with the present invention include the clinical conditions referred to above, and particularly adenoviral infections of the eye.

Preferred esters of the compounds of formula (I) include carboxylic acid esters in which the non-carbonyl moiety of the ester grouping is selected from straight or branched chain alkyl, alkoxyalkyl te.g. methoxymethyl), aralkyl (e.g. benzyl), aryloxyalkyl (e.g. phenoxymethyl), aryl (e.g.
phenyl optionally substituted by halogen, Cl 4 alkyl or Cl 4 alkoxy);
sulphonate esters such as alkyl- or aralkylsulphonyl (e.g.
methanesulphonyl); and mono-, di- or tri-phosphate esters. With regard to the above-described esters, unless otherwise specified, any alkyl moieties present in such esters advantageously contain 1 to 18 carbon atoms, particularly 1 to 4 carbon atoms. Any aryl moiety present in such esters advantageously comprises a phenyl group. Any reference to any of the above compounds also includes a reference to a pharmaceutically acceptable salt thereof.

Examples of pharmaceutically acceptable salts of the compound of formula (I) and its pharmaceutically acceptable derivatives include base salts, e.g. derived from an appropriate base, such as alkali metal (e.g. sodium), alkaline earth metal(e.g. magnesium) salts, ammonium and NX4 (wherein X is Cl 4 alkyl).

The above compounds of formula (I) in which R represents a chlorine or iodine atom and their physiologically acceptable salts and esters are, however, new compounds, the present invention is particularly concerned with the compound (I) in which R is a chlorine atcm and thus represents a feature of the present invention.
The compounds according to the invention may be ~ nictered to humans for the prophylaxis or treatment of adenovirus infections and eye infections in particular, by any suitable route including oral, rectal, nasal, topical (including buccal and sublingual), vaginal and parenteral (including subcutaneous, intramuscular, intravenous and intradermal). It will be appreciated that the preferred route will vary with the condition and age of the recipient, the nature of the infection and the chosen active ingredient.

In general a suitable dose will be in the range of 3.0 to 120 mg per kilogram body weight of the patient per day, preferably in the range of 6 to 90 mg per kilogram body weight per day and most preferably in the range to 60 mg per kilogram body weight per day. The desired dose is preferably presented as two, three, four, five, six or more sub-doses ~. iniqtered at appropriate intervals throughout the day. These sub-doses may be ~ inistered in unit dosage forms, for example, cont~ining lO to 1500 mg, preferably 20 to lO00 mg, and most preferably 50 to 700 mg of the compound per unit dosage form.

While it ls possible for the compounds according to the invention to beadministered alone it is preferably to present it as a pharmaceutical formulation. The formulations of the present invention comprise at least one compound according to the invention together with one or more acceptable carriers thereof and optionally other therapeutic agents. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not in~urious to the patient.
Formulations include those suitable for oral, rectal, nasal, topical (including buccal and sublingual), ophthalmic, vaginal or parenteral A

_ - 5 -(including subcutaneous, intramuscular, intravenous and intradermal) administration. The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active ingredient with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active ingredient with liquid carriers or finely divided solid carriers or both, and then if necssary shaping the product.

In view of the activity of the compounds according to the invention against adenovirus infection of the eye, as referred to above, it is particularly preferred to present the compounds according to the invention in the formulations adapted for ophthalmic administration.

Such formulations for opthalmic administration include eye drops and ophthalmic ointments, creams, suspensions and lotions.

Drops according to the present invention may comprise sterile aqueous or oily solutions or suspensions and may be prepared by dissolving the active ingredient in a suitable aqueous solution of a bactericidal and/or any other suitable preservative. The resulting solution may then be clarified by filtration, transferred to a suitable container which is then sealed and sterilised by autoclaving. Alternatively, the solution may be sterilised by filtration and transferred to the container by an aseptic technique.
Examples of bactericidal and fungicidal agents suitable for inclusion in the drops are phenylmercuric nitrate or acetate (0.002%), benzalkonium chloride (0.01%) and chlorhexidine acetate (0.01%).

Lotions according to the present invention include sterile aqueous solutions optionally containing a preservative and may be prepared by methods similar to those for the preparation of drops.

Creams or ointments according to the present invention are semi-solid formulations of the active ingredient particularly for opthalmic application. They may be made by mixing the active ingredient in _ - 6 -finely-divided or powdered form alone or Ln solution or suspension in an aqueous or non-aqueous fluid, with a greasy or non-greasy basis. The basis may comprise hydrocarbons such as hard, soft or liquid paraffin, glycerol, beeswax, a metallic soap; a mucilage, an oil of natural origin such as almond, corn, arachis, castor or olive oil, wool fat or its derivatives, or a fatty acid such as stearic or oleic acid together with an alcohol such as propylene glycol or macrogols. The formulation may incorporate any suitable surface active agent such as sorbitan esters or polyoxyethylene derivative thereof. Suspending agents such as natural gums, cellulose derivatives or inorganic materials such as silicaceous silicas; and other ingredients such as lanolin may also be included.

Formulations of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented as a bolus or paste.
Oral formulations may further include other agents conventional in the art, such as sweeteners, flavouring agents and thickeners.

A tablet may be made by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable nchlne the active ingredient in a free-flowing form such as a powder or granules, optionally incorporating a binder (e.g.
povidone, gelatin, hydroxypropylmethyl cellulose), lubricant, inert diluent, disintegrant (e.g. sadium starch glycollate, cross-linked povidone, cross-linked sodium carboxymethyl cellulose), surface-active or dispersing agent. Moulded tablets may be made by moulding in a suitable nrh~ne a mixture of the powdered compounds moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile.

_ 7 1 333392 Formulations suitable for topical administration in the mouth include lozenges comprising the active ingredient in a flavoured basis, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert basis such as gelatin and glycerin, or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.

Formulations for rectal administration may be presented as a suppository with a suitable base comprising for example cocoa butter or a salicylate.

Formulations suitable for vaginal administration may be present as pessaries, tampons, creams, gels, pastes, foams or spray formulations contain~n~ in addition to the active ingredient such carriers as are known in the art to be appropriate.

Formulations suitable for parenteral administration include aqueous andnon-aqueous isotonic sterile in~ection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for in;ections, immediately prior to use. Extemporaneous injection solutions and suspensions ~ay be prepared from sterile powders, granules and tablets of the kind previously described.

Preferred unit dosage formulations are those cont~ning a daily dose or daily sub-dose, as herein above recited, or an appropriate fraction, of the compound according to the invention.

The compounds according to the invention may be prepared in conventional manner.

- 8 - 1 3 3 3 3 ~ 2 The compounds of formula (I) in which R represents a halogen (particularly a chlorine or iodine) atom may be prepared, for example, by halogenating a corresponding compound of formula (I) in which R represents a hydrogen atom and in which the 5'-hydroxy group is blocked, for example by an acyl group such a p-toIuoyl group.

Halogenation of the above starting material may be effected in conventional manner, for example lodination using iodine monochloride, e.g. in methylene dichloride and chlorination using a chlorine complex of iodobenzene, e.g.
in glacial acetlc acld.

The above toluoyl derivative may be prepared by treating the appropriate compound of formula (I) with for example p-toluoyl chloride, eg in pyridine. After halogenation as described above, the p-toluoyl protecting group may be removed for example by sodium muthoxide in methanol.

The parent compound of formula (I) may be converted into a physiologically acceptable ester by reactlon with an appropriate esterifying agent, e.g. an acid halide or anhydride. The compound of formula (I), including esters thereof, may be converted into pharmaceutically acceptable salt thereof in conventional manner, e.g. by treatment with an appropriate base. An ester or salt m~y be converted into the parent compound, e.g. by hydrolysis.

The following Examples are intended for illustration only and are not intended to limit the scope of the invention in any way. The term 'active ingredient' as used in the Examples means a compound of formula (I) or a physiologically acceptable salt or ester thereof. m ese Examples describe the compounds of the invention and related compounds.
Example 1 1-(2.3-Dideoxy-3-fluoro-~-D-erythro-Dentofuranosyl)-5-iodouracil ~-Toluoyl chloride (freshly distilled, 325mg, 2.10 mmol) was added to a solution of 1-(2,3-dideoxy-3-fluoro-~-D-erythro-pentofuranosyl)uracil A
.~

1 3333~2 (440mg, 1.91 mmol) in dry pyridine (lOml). The solution was stirred at 50 for 1.5 hour, and then at 25 for 18 hours. The pyridine was evaporated and the residue dissolved in CHC13 (25ml). This solution was extracted with lM H2SO4 (5ml), then H2O (2 x 10 ml), and dried (MgS04). Evaporation of CHC13 left a colourless glass (0.72g) which was chromatographed on silica gel. Elution with 2% MeOH-CHC13 gave the 5'-O-toluoyl derivative as white solid foam (0.66g, 90%); chromatographically homogeneous on TLC
plates (silica gel developed with 5% MeOH-CHC13); structure confirmed by 'H-NMR.

The 5'-0-toluoyl derivative of 1-(2,3-dideoxy-3-fluoro-~-D-erythro-pentofuranosyl)uracil (200mg, 0.574 mmol), iodine monochloride (139 mg, 0.861 mequiv), and CH2C12 (lOml) were refluxed for 2 hours. The solution was decolourised with a minimum of 2% aqueous NaHSO3 (ca. 2ml). The aqueous layer was separated and the CH2C12 layer washed with H2O (2x5ml) and dried (MgSO4). Evaporation of CH2C12 left a cream colored solid foam (0.25g) which was dissolved in MeOH (lOml) and stirred with sodium methoxide (0.57 mmol) under N2 at 25 for 18 hours. The solution was neutralized with Dowex 50W-X8 (H form) resin. The resin was filtered off, washed with MeOH, and the contents of the methanol filtrate wash chromatographed on silica gel. Elution with 10~ MeOH-CH2C12 gave a product as a white solid (0.135g). Recrystallization from EtOH gave title compound as white crystals (115mg, 55% overall yield); m.p. 197.5-198 dec; Anal:
Calcd for C9HloFN204: C, 30.36; H, 2.83; N, 7-87; F, 5-34; I, 35-64-Found: C, 30.50; H, 2.85; N, 7.85; F, 5.31; I, 35.51; W ~ max (H20): 286 nM; structure further confirmed by 'H-NMR and mass spectrum.

- lo - 1 3 3 3 3 9 2 ExampIe 2 5-Chloro-1-(2'.3-dideoxy-3'-fluoro-B-D-erythro-pentofuranosyl)uracil The chlorine complex of iodobenzene was freshly prepared as described in the literature (see M.J. Robins, et al., Can. J. Chem. 1982, 60, 554) and 246mg (0.895mmol) added to a solution of the S'-0-toluoyl derivative of 1-(2,3-dideoxy-3-fluoro-~-D-erythro-pentofuranosyl)uracil (260mg, 0.746 mmol), prepared as described in Example 1, in glacial acetic acid (4ml).
This solution was maintained at 80 under nitrogen for 20 minutes and evaporated to a white solid foam. Treatment with sodium methoxide in methanol was carried out as in Example 1. Chromatography on 2mm thick silica gel plates (20 x 20cm) developed in CHC13: MeOH: NH40H/180:20:1 was required to separate 5-chlorouracil (slightly greater Rf) from title compound, isolated as an off-white solid (46mg). Trituration in methanol gave title compound as white needles (34mg); m.p. 183-184 ; Anal. Calcd for CgHloClFN2O4: C, 40.85; H, 3.81; Cl, 13.40; N, 10.59. Found: C, 40.71; H, 3.85; Cl, 13.31; N, 10.55; W ~ max (H2O) 275 nM; structure further confirmed by 'H-NMR and mass spectrum.

Example 3 Tablet Formulations The following formulations A, B and C are prepared by wet granulation of the ingredient~ with a solution of povidone, followed by addition of magnesium stearate and compression.

Formulation A
mg~tablet mg/tablet (a) Active ingredient 250 250 (b) Lactose B.P. 210 26 (c) Povidone B.P. 15 9 (d) Sodium Starch Glycollate 20 20 (e) Magnesium Stearate 5 3 Formulation B
mg/tablet m~/tablet (a) Active ingredient 250 250 (b) Lactose 150 (c) Avicel PH 101 60 26 (d) Povidone B.P. 15 9 (e) Sodium Starch Glycollate 20 12 (f) Magnesium Stearate __~ 3 Formulation C
mg/tablet Active Ingredient 100 Lactose 200 Starch 50 Povidone B.P. 5 Magnesium Stearate 4 The following formulations, D and E, are prepared by direct compression of the admixed ingredients. The lactose used in formulation E is of the direct compression type.

- 12 - l 3 3 3 3 9 2 Formulation D
mg/capsule Active In~redient 250 Pregelatinised Starch NF15 150 Formulation E
m~/capsule Active Ingredient 250 Lactose B.P. 150 Avicel 100 Magnesium Stearate 5 Formulation F (Controlled Release Formulation~

The formulation is prepared by wet granulation of the ingredients (below) with a solution of povidone followed by the addition of magnesium stearate and compression.

m~/tablet (a) Active Ingredient 500 (b) Hydroxypropylmethylcellulose 112 (Methocel K4M Premium) (c) Lactose B.P. 35 (d) Povidone B.P.C. 28 (e) Magnesium Stearate 7 ExamDle 4 Ca~sule Formulations Formulation A

A capsule formulation is prepared by admixing the ingredients of Formulation D in Example 1 above and filling into a two-part hard gelatin capsule. Formulation B (infra) is prepared in a similar manner.

Formulation B
m~/capsules (a) Active Ingredient 250 (b) Lactose B.P. - 143 (c) Sodium Starch Glycollate 25 (d) Magnesium Stearate 2 Formulation C
m~/capsule (a) Active Ingredient 250 (b) Macrogol 4000 BP 350 Capsules are prepared by melting the macrogol 4000 BP, dispersing the active ingredient in the melt and filling the melt into a two-part hard gelatin capsule.

Formulation D
mg/capsule Active Ingredient 250 Lecithin 100 Arachis Oil 100 Capsules are prepared by dispersing the active ingredient in the lecithin and arachis oil and filling the dispersion into soft, elastic gelatin capsules.

~ - 14 - 1 3 3 3 3 9 2 Formulation E (Controlled Release Ca~sule The following controlled relase capsule formulation was prepared by extruding ingredients (a), (b) and (c) using an extruder, followed by spheronisation of the extrudate and drying. The dried pellets were then coated with release-controlling membrane (d) and filled into a two-piece, hard gelatin capsule.

mg/capsule (a) Active Ingredient 250 (b) Microcrystalline Cellulose 125 (c) Lactose BP 125 (d) Ethyl Cellulose 13 Example 5. In~ectable Formulation Formulation A.
Active Ingredient 0.200g Hydrochloric acid solution, O.lMq.s. to pH 4.0 to 7.0 Sodium hydroxide solution, O.lMq.s. to pH 4.0 to 7.0 Sterile water q.s. to lOml The active ingredient is dissolved in most of the water (35 -40 C) and the pH ad~usted to between 4.0 and 7.0 with the hydrochloric acid or the sodium hydroxide as appropriate. The batch is then made up to volume with the water and filtered through a sterile micropore filter into a sterile lOml amber glass vial (type 1) and sealed with sterile closures and overseals.

Formulation B.

Active Ingredient 0.125g Sterile, pyrogen-free,pH 7 citrate buffer, q.s. to 25ml - 15 - 1 3 3 3 3 9 ~

Example 6 Intramuscular In~ection Active Ingredient 0.20g Benzyl Alcohol 0.10g Glycofurol 75 1.45g Water for In;ection q.s. to 3.00ml The active ingredient is dissolved in the glucofurol. The benzyl alcohol is then added and dissolved, and water added to 3ml. The mixture was then filtered through a sterile micropore filter and sealed in sterile 3ml amber glass vials (type 1).

Example 7 Eye Drops Active Ingredient 0.20 g Benzalkonium Chloride 0.01 g Isotonic, phosphate buffer, pH 7 to 10.00 ml The active ingredient is dissolved in most of the Isotonic phosphate buffer. The benzalkonium chloride is added and dissolved and the batch made to volume with further Isotonic phosphate buffer. The solution is filtered through a sterile, sterilising grade filter and packed into sterile eye drop bottles and sealed.

Exam~le 8 Eye Oint~n~

Active Ingredient . 0.5 g Sterile White Soft Paraffin to 5.0 g The active ingredient is sterilised by dry heat and mixed with the Sterile White Soft Paraffin under aseptic conditions. The resulting dispersion is packed into sterile ophthalmic ointment tubes.

- 16 ~ l 3 3 3 3 9 2 Example 9 O~hthalmic Suspension Active Ingredient O.lg Polysorbate 80 0.005 g Thiomersal 0.001 g Propylene Glycol 0.1 g Water for In~ection to 5.0 ml The Polysorbate 80, Thiomersal and Propylene Glycol are dissolved in most of the Water for In~ections.

The solution is sterilised by filtration. The sterile, micronised active ingredient is dispersed in the solution under aseptic conditions. The batch is made up to volume with further Water for In~ections which has been sterilised previously. The product is packed into sterile eye drop bottles and sealed.

Antiviral Activity The anti-adenoviral activity of Compound No. 3 referred to above was tested as follows:-Cells of human epithelial cell line NCTC 2544 (EP) were serially passagedfrom 75cm2 tissue culture flasks (Corning) at a split ratio of 1/20 every 7 days. Th- growth medium was Eagles BHK medium supplemented with 10% foetal bovine sorum and contained 2.5~ of 4.4~ sodium bicarbonate solution together with 1~ of penicillin (5000 IU ml 1) and streptomycin (600 ~g ml ) (Flow).

A stock of adenovirus of type 8 was prepared in 25 cm2 tissue culture flasks. Flasks were seeded with 2 x 10 EP cells in growth medium and incubated overnight at 37C. The medium was decanted and 1.0 ml of stock virus suspension was added to the flask. After l.0 hr adsorption lO ml of maintenance medium (as above but with 2% serum) was added to the flask.

_ - 17 -The flask were incubated at 37 C. After 72 hrs the classical'bunch ofgrapes' cytopathic effect was visible. The flasks were then frozen and thawed 3 times to liberate the virus and stored at -70 C. Viral titres were usually of the order of 4 x 10 pfu ml The plaque assay was performed in 50mm diameter plastic tissue culture dishes whch were inltially seeded with 2 x I06 EP cells in growth medium and incubated overnight in 5~ CO2 at 37 C. Adenovirus was inoculated on to the cell monolayers in 1.0 ml serum-free medium and allowed to adsorb at 37 C in a CO2 incubator for 1 hr. After adsorption excess inoculum was removed and 9.0 ml overlay medium was added. This consisted of 0.5%
agarose, Eagles BHK medium, 2.5% of 4.4% sodium bicarbonate solution, 1.5%
foetal bovine serum, 1% of penicillin/streptomycin solution and 0.5% of 3 M
magnesium chloride solution. From day 5 when plaques could be seen in the unstained culture, the cultures were fixed in 10% of 40% formaldehyde solution in phosphate buffered salt solution. After one hour the overlay gel was rinsed from the plate with tap water and the exposed monolayer stained with 2 ml of 0.5% methyl violet in 5% methanol.

EP cells allowed the productive growth of adenovirus and plaques wereclearly visible.

The following results was obtained for the activity of the above Compound against adenovirus of sérotype 8:-Compound No. IC50(~M) 3 0.005 Cytotoxicity Determination Cytotoxicity was determined by means of the trypan blue exclusion method.NCTC 2544 cells were prepared in growth medium and aliquots added to 25cm tlssue culture flasks at approximately 1 x 105 cells/ml. At 24 hours the flasks were divided and replenished with growth medium. One half of the - 18 - l 3333~2 flasks received growth medium contaLning 10 fold dilutions of compound thus exposing the cells to 1, 10j and 100~M concentrations. At 24, 48, and 72 hours representative flasks were removed from the incubator and the monolayers washed to remove debrls. The cells were resuspended in growth medium and aliquots mixed with an equal volume of trypan blue. Stained and unstained cells were counted in a haemocytometer. Cell counts were ad~usted to cells/ml. An estimate of the growth and viability of treated and untreated cells was then made.

The 50% cell culture inhibitory concentratlon of compound No. 3) was 38~M
at 72 hours.

Preparation of 1-(2-Deoxy-5-(p-chlorobenzoyl)-B-D-threo-~entofuranosyl)-thy~ine 1-(2-Deoxy-~-D-threo-pentofuranosyl)thymine (J.J. Fox and N.C. Miller J.
Org. Chem., 1963, 28, 936) (49.0g) was disqolved in 500 ml of anhydrous pyridine in a lL round bottom flask equipped with an addition funnel, nitrogen inlet and mechanical stirrer. The solution was cooled to 5 C in an ice bath and 4-chlorobenzoyl chloride (35.4g, 0.202mol) was added dropwise over 30 minutes. The solution was allowed to gradually warm to ambient temperature. The reaction was quenched with water (20ml), most of the pyridine removed by rotary evaporation and the residual oil dissolved in ethyl acetate (lL). The organic solution was washed with 700ml portions of water, 1.2N HCl and 10~ aqueous sodium bicarbonate and dried over sodium sulphate. The mixture was then filtered and solvent removed by rotary evaporation affording 1-(2-deoxy-5-(p-chlorobenzoyl)-D-threo-pentofurano~yl)~h~ ~n~ (62.lg,80.7~) as an off-white solid suitable for use in the next ~tep: lH NMR (DMSO-d6) 1.76 (d, J-0.9Hz, 3H, C-5 CH2), 2.1-2.6 (m, 2H, C-2'), 3.8-4.5 (m, 4H, C-3'H, C-4'H and C-5'H), 5.55 (d, J-2.6Hz, lH, C-3'0H), 6.13 (doublet of doublets, J-2.8Hz and 8.3Hz, lH, C-l'H), 7.58 (d, J-8.6Hz, 2H, ArH), 7.81 (m, lH, C-6H), 7.85 (d, J-8.6Hz, 2H, ArH); TLC, Rf-0.72, silica gel, CHC13 : CH30H/90:10.

Pre~aration of 3'-Deoxy-3'-fluoro-thymidine A suspension of 1-(2-deoxy-5-(p-chlorobenzoyl)-~-D-threo-pentofuranosyl)-thymine (61.0g) and potassium carbonate (30.0g) ln methylene chloride (700ml) was cooled to -78 C in a 2L round bottom flask equipped with a mechanical stlrrer, addition funnel and nitrogen inlet. Diethylamino sulfurtrifluoride (30ml) was added dropwise over 10 minutes and stirring was continued an additional 2.5h at -78C. The solution was warmed to room temperature, transferred to a separatory funnel and washed with ice water (700ml), and 500ml portions of water, 1.2N hydrochloric acid and 10~
aqueous sodium bicarbonate. The solvent was removed by rotary evaporation and the residue was dissolved in methanol (500ml). Solid sodium bicarbonate (15g) was added and the suspension was heated 2h at reflux.
The mixture was cooled to room temperature, filtered, solvent removed by rotary evaporation and the residual oil purified by flash chromatography using a 3 x 36 inch volume of flash silica gel. The column was eluted with 96:4/CHC13:CH30H while collecting 200ml fractions. Fractions 29-41 were concentrated by rotary evaporation, the residue slurried in acetone (lOOml) and the solids collected by filtration affording 7.70g (19.9%) of 3'-deoxy-3'-fluorothymidine: mp - 169-171 C; TLC, Rf- 0.53, Silica Gel, 90:10 /
CHC13:CH30H; Elemental Analysis Calc C, 49.18; H, 5.37; N, 11.47; Found C, 49.00; 5.38; N, 11.40.

Claims (38)

1. A compound of formula (I):

(I) wherein R represents a chlorine atom or a physio-logically acceptable salt or ester thereof.

2. 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-ery-thro-pentofuranosyl)uracil.

3. A physiologically acceptable salt of 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pentofuran-osyl)uracil.

4. A physiologically acceptable ester of 5-chloro-l-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pento-furanosyl)uracil.

5. A compound, salt or ester according to claim 1, 2, 3 or 4, for use in the treatment or prophylaxis of an adenovirus infection.

6. A compound, salt or ester according to claim 5, wherein the adenovirus infection is caused by an adenovirus of Serotype 8.

7. A compound, salt or ester according to claim 5, wherein the adenovirus infection is caused by an adenovirus of Serotype 5.

8. Use of a compound, salt or ester according to claim 1, 2, 3 or 4, in the manufacture of a medica-ment for the treatment or prophylaxis of an adenovirus infection.

9. Use of a compound, salt or ester according to claim 8, wherein the medicament is for the treat-ment or prophylaxis of an adenovirus of Serotype 8.

10. Use of a compound, salt or ester according to claim 8, wherein the medicament is for the treat-ment or prophylaxis of an adenovirus or Serotype 5.

11. An anti-adenovirus infection pharmaceutical formulation comprising an effective anti-adenovirus infection amount of a compound, salt or ester accord-ing to claim 1, 2, 3 or 4, in associated with a pharmaceutically acceptable carrier.

12. A pharmaceutical formulation according to claim 11, adapted for ophthalmic administration.

13. A pharmaceutical formulation according to claim 12, in the form of eye drops.

14. A pharmaceutical formulation according to claim 12, in the form of ophthalmic ointment, cream, suspension or lotion. `

15. A pharmaceutical formulation according to claim 11, adapted for oral administration.

16. A pharmaceutical formulation according to claim 15, in the form of a tablet or capsule.

17. A pharmaceutical formulation according to claim 11, presented in a unit dosage form.

18. A pharmaceutical formulation according to claim 12, 13, 14, 16 or 17, presented in a unit dosage form.

19. A pharmaceutical formulation according to claim 17, each unit dosage form containing 10 to 1500 mg of said compound, salt or ester.

20. A pharmaceutical formulation according to claim 18, each unit dosage form containing 10 to 1500 mg of said compound, salt or ester.

21. A pharmaceutical formulation according to claim 19, each unit dosage form containing 50 to 700 mg of a compound of formula (I) or a physiologically acceptable salt or ester thereof.

22. A pharmaceutical formulation according to claim 18, each unit dosage form containing 50 to 700 mg of a compound of formula (I) or a physiologically acceptable salt or ester thereof

23. An anti-adenoviral pharmaceutical formu-lation for the treatment or prophylaxis of adenovirus infections comprising a physiologically acceptable and effective amount of 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pentofuranosyl)uracil, or a physiologi-cally acceptable salt or ester thereof, in association with a pharmaceutically acceptable carrier.

24. A pharmaceutical formulation comprising an effective amount of a compound, salt or ester accord-ing to claim 1, 2, 3 or 4, in association with a pharmaceutically acceptable carrier.

25. A pharmaceutical formulation according to claim 24, adapted for ophthalmic administration.

26. A pharmaceutical formulation according to claim 25, in the form of eye drops.

27. A pharmaceutical formulation according to claim 25, in the form of ophthalmic ointment, cream, suspension or lotion.

28. A pharmaceutical formulation according to claim 24, adapted for oral administration.

29. A pharmaceutical formulation according to claim 28, in the form of a tablet or capsule.

30. A pharmaceutical formulation according to claim 24, presented in a unit dosage form.

31. A pharmaceutical formulation according to claim 25, 26, 27, 28, 29 or 30, presented in a unit dosage form.

32. A pharmaceutical formulation according to claim 30, each unit dosage form containing 10 to 1500 mg of said compound, salt or ester.

33. A pharmaceutical formulation according to claim 31, each unit dosage form containing 10 to 1500 mg of said compound, salt or ester.

34. A pharmaceutical formulation according to claim 32, each unit dosage form containing 50 to 700 mg of a compound of formula (I) or a physiologically acceptable salt or ester thereof.

35. A pharmaceutical formulation according to claim 31, each unit dosage form containing 50 to 700 mg of a compound of formula (I) or a physiologically acceptable salt or ester thereof.

36. A pharmaceutical formulation comprising a physiologically acceptable and effective amount of 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pento-furanosyl)uracil, in association with a pharma-ceutically acceptable carrier.

37. A pharmaceutical formulation comprising a physiologically acceptable and effective amount of a physiologically acceptable salt of 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pentofuranosyl)uracil, in association with a pharmaceutically acceptable carrier.

38. A pharmaceutical formulation comprising a physiologically acceptable and effective amount of a physiologically acceptable ester of 5-chloro-1-(2,3-dideoxy-3-fluoro-.beta.-D-erythro-pentofuranosyl)uracil, in association with a pharmaceutically acceptable carrier.