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WO1993006112A1 - Nucleosides a usage therapeutique - Google Patents

Nucleosides a usage therapeutique Download PDF

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Publication number
WO1993006112A1
WO1993006112A1 PCT/GB1992/001748 GB9201748W WO9306112A1 WO 1993006112 A1 WO1993006112 A1 WO 1993006112A1 GB 9201748 W GB9201748 W GB 9201748W WO 9306112 A1 WO9306112 A1 WO 9306112A1
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WO
WIPO (PCT)
Prior art keywords
oxo
dihydro
methoxy
purin
enantiomer
Prior art date
Application number
PCT/GB1992/001748
Other languages
English (en)
Inventor
Wayne Howard Miller
Stanley Dawes Chamberlain
Karen Kathleen Biron
Original Assignee
The Wellcome Foundation Limited
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Publication date
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Publication of WO1993006112A1 publication Critical patent/WO1993006112A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D473/00—Heterocyclic compounds containing purine ring systems
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
    • C07C69/78—Benzoic acid esters
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/18—Compounds having one or more C—Si linkages as well as one or more C—O—Si linkages
    • C07F7/1804—Compounds having Si-O-C linkages
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
    • C07F9/02—Phosphorus compounds
    • C07F9/547—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom
    • C07F9/6561—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom containing systems of two or more relevant hetero rings condensed among themselves or condensed with a common carbocyclic ring or ring system, with or without other non-condensed hetero rings
    • C07F9/65616—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom containing systems of two or more relevant hetero rings condensed among themselves or condensed with a common carbocyclic ring or ring system, with or without other non-condensed hetero rings containing the ring system having three or more than three double bonds between ring members or between ring members and non-ring members, e.g. purine or analogs
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H9/00—Compounds containing a hetero ring sharing at least two hetero atoms with a saccharide radical
    • C07H9/02—Compounds containing a hetero ring sharing at least two hetero atoms with a saccharide radical the hetero ring containing only oxygen as ring hetero atoms
    • C07H9/04—Cyclic acetals

Definitions

  • the present invention relates to an antiviral phosphonate derivative of an acyclic purine nucleoside analog and pharmaceutically acceptable derivatives thereof, to compositions containing them, to their use in medical therapy, particularly for the treatment of certain viral infections, and to methods for preparing the R-enantiomer of the phosphonate derivative substantially free from the corresponding S-enantiomer.
  • the herpes group is the source of many common viral illnesses in man.
  • the group includes cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV), herpes simplex virus (HSV) and human herpes virus 6 (HHV6).
  • CMV cytomegalovirus
  • EBV Epstein-Barr virus
  • VZV varicella zoster virus
  • HSV herpes simplex virus
  • HHV6 human herpes virus 6
  • CMV infection with CMV leads to a life-long association of virus and host and, following a primary infection, virus may be shed for a number of years.
  • CMV infection in AIDS patients is a predominant cause of morbidity as, in 40 to 80% of the adult population, it is present in a latent form and can be reactivated in immunocompromised patients.
  • EBV causes infectious mononucleosis and is also suggested as the causative agent of nasopharyngeal cancer, immunoblastic lymphoma, Burkitt's lymphoma and hairy leukoplakia.
  • VZV causes chicken pox and shingles.
  • Chicken pox is the primary disease produced in a host without immunity. In young children, it is usually a mild illness characterized by a vesicular rash and fever. Shingles is the recurrent form of the disease which occurs in adults who were previously infected with varicella.
  • the clinical manifestations of shingles include neuralgia and a vesicular skin rash that is unilateral and dermatomal in distribution. Spread of inflammation may lead to paralysis or convulsions and coma can occur if the meninges become affected. In immunodeficient patients, VZV may disseminate causing serious or even fatal illness.
  • HSV 1 and HSV 2 are some of the most common infectious agents of man.
  • HSV infection is often characterized by extensive lesions of the skin, mouth and/or genitals. Primary infections may be subclinical although they tend to be more severe than infections in individuals previously exposed to the virus.
  • Ocular infections by HSV can lead to keratitis or cataracts.
  • HHV6 is the causative agent of roseola infantum (exanthum subiturn) in children which is characterized by fever and the appearance of a rash after the fever has declined. HHV6 has also been implicated in syndromes of fever and/or rash and pneumonia or hepatitis in immunocompromised patients.
  • Acyclic nucleoside phosphonates have been previously proposed for the treatment of herpes virus infections.
  • EPO 0 173 624 describes 9-(3-phos ⁇ hono-1-propoxymethyl)guanine.
  • Duke, A.E. et. al., Antiviral Res. (1986) 6:299-308; Prisbe, E.J. et. al., J. Med. Chem. (1986) 29:671-675 and PCT Patent Application WO 88/05438 describe racemic 9-(3-phosphono-1-hydroxymethyl-1-propoxymethyl)guanine (ie. ganciclovir phosphonate) and related compounds.
  • esters and salts of esters thereof have an especially advantageous combination of therapeutic properties in terms of their antiviral activity and/or other properties relevant to their use as antivirals that render these enantiomeric compounds of exceptional benefit as therapeutic agents, in particular as anti-herpes virus agents, more particularly as anti-CMV, -EBV, VZV or -HHV6 agents, especially in comparison with the above-mentioned racemic ganciclovir phosphonate and also ganciclovir.
  • the R-enantiomer of ganciclovir phosphonate, the compound of formula (la), can also be named (R)-3-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9- yl)methoxy]-4-hydroxybutylphosphonic acid.
  • the R-enantiomer of ganciclovir phosphonate substantially free from the S-enantiomer thereof, and salts, esters or salts of esters of said R-enantiomer.
  • the R-enantiomer of ganciclovir phosphonate is substantially free from the corresponding S-enantiomer to the extent that it is generally in admixture with less than 10% w/w, preferably less than 5% w/w and most preferably less than 2% w/w of S-enantiomer, based on the total weight of the mixture.
  • the above R-enantiomer, according to the invention advantageously contains less than 1% w/w of the corresponding S-enantiomer.
  • esters or salts of esters is meant any salt, ester or salt of an ester which upon administration to the recipient, is capable of providing (directly or indirectly) the compound of formula (la) or an active metabolite or residue thereof.
  • esters in accordance with the invention, include carboxylic acid esters of the hydroxymethyl group in which the non-carbonyl moiety of the carboxylic acid portion of the ester grouping is selected from straight or branched chain alkyl e.g., n-propyl, t-butyl, n-butyl, alkoxyalkyl (e.g., methoxymethyl), alkenyl (e.g., 2-butenyl), arylalkyl (e.g., benzyl), aryloxyalkyl (e.g., phenoxymethyl), aryl (e.g., phenyl optionally substituted by halogen, C 1-4 alkyl or C 1-4 alkoxy); sulfonate esters such as alkyl- or alkylarylsulfonyl (e.g., methanesulfonyl); amino acid esters (e.g., L-valyl or L-isoleucyl,
  • the phosphate esters may be further esterified by, for example, a C 1-20 alcohol or reactive derivative thereof, or by a 2,3-di(C 6-24 )acyl glycerol.
  • Additional preferred esters include mono or diesters of the phosphonic acid group in which the phosphonic acid group is mono or disubstituted with substituents selected from straight or branched chain alkyl e.g., n-propyl, t-butyl, n-butyl, alkoxyalkyl (e.g., methoxymethyl), acyloxyalkyl (e.g., acetoxymethyl), alkenyl (e.g., 2-butenyl), arylalkyl (e.g., benzyl), aryloxyalkyl (e.g., phenoxymethyl), aryl (e.g., phenyl optionally substituted by halogen, C 1-4 alkyl or C 1-4 alkoxy).
  • any alkyl moiety present advantageously contains 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 (la) 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 NX 4 + , (wherein X is C 1-4 alkyl).
  • 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 NX 4 + , (wherein X is C 1-4 alkyl).
  • Pharmaceutically acceptable salts further include acid salts, e.g., derived from an appropriate organic carboxylic acid, such as acetic, fumaric, citric, lactic, tartaric, maleic, isethionic, lactobionic and succinic acids; organic sulfonic acids such as methanesulfonic, ethanesulfonic, benzenesulfonic and p-toluenesulfonic acids and inorganic acids such as hydrochloric, hydrobromic, sulfuric, phosphoric and sulfamic acids.
  • organic carboxylic acid such as acetic, fumaric, citric, lactic, tartaric, maleic, isethionic, lactobionic and succinic acids
  • organic sulfonic acids such as methanesulfonic, ethanesulfonic, benzenesulfonic and p-toluenesulfonic acids
  • inorganic acids such as hydrochloric, hydrobro
  • the present invention further includes:
  • a method for the treatment of a viral infection more preferably a herpes virus infection, in particular a CMV, EBV, VZV or HHV6 infection, in a mammal, including a human, which comprises treating said mammal with an effective anti-herpes virus amount of the R-enantiomer which is substantially free of the S-enantiomer of ganciclovir phosphonate or a pharmaceutically acceptable salt, ester or salt of such ester thereof.
  • a pharmaceutical formulation comprising the R-enantiomer of ganciclovir phosphonate substantially free of the S-enantiomer or a pharmaceutically acceptable salt, ester or salt of such ester thereof together with a pharmaceutically acceptable carrier therefor.
  • Examples of clinical conditions caused by herpes viruses such as CMV, EBV, VZV and HHV6 infections, which may be treated in accordance with the invention, include those referred to above. It will be recognized that while a racemic mixture of the compounds of formulae (la) and (lb) can also be used for treating the aforementioned conditions, for example those caused by HHV6 infection, use of the compound of formula (la) is preferred.
  • the compound of formula (la) may be employed in combination with other therapeutic agents for the treatment of the above infections or conditions.
  • further therapeutic agents include agents that are effective for the treatment of herpes virus infections such as 1- ⁇ -D-arabinofuranosyl-5-(1-propynyl)uracil, foscarnet, acyclovir or ganciclovir, interferons, for example, ⁇ -interferon, or benzimidazole nucleosides such as those disclosed in WO 92/07867.
  • the component compounds of such combination therapy may be administered simultaneously, in either separate or combined formulations, or at different times, e.g., sequentially, such that a combined effect is achieved.
  • the compound of formula (la), also referred to herein as the active ingredient, may be administered for therapy by any suitable route including oral, rectal, nasal, topical (including transdermal, buccal and sublingual), vaginal, parenteral (including subcutaneous, intramuscular, intravenous and intradermal) and pulmonary. It will also be appreciated that the preferred route will vary with the condition and age of the recipient and the nature of the infection.
  • a suitable dose for each of the above named viral infections is in the range of 0.1 to 250 mg per kilogram body weight of the recipient per day, preferably in the range of 1 to 100 mg per kilogram body weight per day and most preferably in the range 5 to 20 mg per kilogram body weight per day.
  • the desired dose may be presented weekly or daily as one, two, three, four, five, six or more doses administered at appropriate intervals throughout the week or the day. These doses may be administered in unit dosage forms, for example, containing 10 to 1000 mg, preferably 20 to 500 mg, and most preferably 100 to 400 mg of active ingredient per unit dosage form.
  • the active ingredient should be administered to achieve peak plasma concentrations of the active compound of from about 0.25 to about 100 ⁇ M, preferably about 0.5 to 70 ⁇ M, most preferably about 1 to about 50 ⁇ M. This may be achieved, for example, by the intravenous injection of a 0.1 to 5% solution of the active ingredient, optionally in saline, or orally administered, for example, as a tablet, capsule or syrup containing about 0.1 to about 250 mg per kilogram of the active ingredient. Desirable blood levels may be maintained by a continuous infusion to provide about 0.01 to about 5.0 mg/kg/hour or by intermittent infusions containing about 0.4 to about 15 mg per kilogram of the active ingredient.
  • the active ingredient While it is possible for the active ingredient to be administered alone, it is preferable to present it as a pharmaceutical formulation comprising at least one active ingredient, as defined above, together with one or more pharmaceutically acceptable carriers therefor 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 injurious to the patient.
  • Formulations include those suitable for oral, rectal, nasal, topical
  • 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 necessary shaping the product.
  • 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 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, electuary or paste.
  • 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 machine the active ingredient in a free- flowing form such as a powder or granules, optionally mixed with a binder (e.g., povidone, gelatin, hydroxypropylmethyl cellulose), lubricant, inert diluent, preservative, disintegrant (e.g., sodium starch glycollate, cross-linked povidone, cross-linked sodium carboxmethyl cellulose) surface-active or dispersing agent.
  • Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound 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. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.
  • 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.
  • compositions for topical administration may be formulated as an ointment, cream, suspension, lotion, powder, solution, paste, gel, spray, aerosol or oil.
  • a formulation may comprise a patch or a dressing such as a bandage or adhesive plaster impregnated with active ingredients and optionally one or more excipients or diluents.
  • the formulations are preferably applied as a topical ointment or cream containing the active ingredient in an amount of, for example, 0.075 to 20% w/w, preferably 0.2 to 25% w/w and most preferably 0.5 to 10% w/w.
  • the active ingredient may be employed with either a paraffinic or a water-miscible ointment base.
  • the active ingredients may be formulated in a cream with an oil-in-water cream base.
  • the aqueous phase of the cream base may include, for example, at least 30% w/w of a polyhydric alcohol, i.e., an alcohol having two or more hydroxyl groups such as propylene glycol, butane-1,3-diol, mannitol, sorbitol, glycerol and polyethylene glycol and mixtures thereof.
  • the topical formulations may desirably include a compound which enhances absorption or penetration of the active ingredient through the skin or other affected areas. Examples of such dermal penetration enhancers include dimethylsulphoxide and related analogues.
  • the oily phase of the emulsions of this invention may be constituted from known ingredients in a known manner. While this phase may comprise merely an emulsifier (otherwise known as an emulgent), it desirably comprises a mixture of at least one emulsifier with a fat or an oil or with both a fat and an oil. Preferably, a hydrophilic emulsifier is included together with a lipophilic emulsifier which acts as a stabilizer. It is also preferred to include both an oil and a fat.
  • Emulgents and emulsion stabilizers suitable for use in the formulation of the present invention include Tween 60, Span 80, cetostearyl alcohol, myristyl alcohol, glyceryl mono-stearate and sodium lauryl sulphate.
  • the choice of suitable oils or fats for the formulation is based on achieving the desired cosmetic properties, since the solubility of the active compound in most oils likely to be used in pharmaceutical emulsion formulations is very low.
  • the cream should preferably be a non-greasy, non-staining and washable product with suitable consistency to avoid leakage from tubes or other containers.
  • Straight or branched chain, mono- or dibasic alkyl esters such as di-isoadipate, isocetyl stearate, propylene glycol diester of coconut fatty acids, isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate, 2-ethylhexyl palmitate or a blend of branched chain esters known as Crodamol CAP may be used, the last three being preferred esters. These may be used alone or in combination depending on the properties required. Alternatively, high melting point lipids such as white soft paraffin and/or liquid paraffin or other mineral oils can be used.
  • Formulations suitable for topical administration to the eye also include eye drops wherein the active ingredient is dissolved or suspended in a suitable carrier, especially an aqueous solvent for the active ingredient.
  • the active ingredient is preferably present in such formulations in a concentration of 0.5 to 20%, advantageously 0.5 to 10% particularly about 1.5% w/w.
  • 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 presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active ingredient, such carriers as are known in the art to be appropriate.
  • Formulations suitable for nasal administration wherein the carrier is a solid, include a coarse powder having a particle size, for example, in the range 20 to 500 microns which is administered in the manner in which snuff is taken, i.e., by rapid inhalation through the nasal passage from a container of the powder held close up to the nose.
  • Formulations suitable for parenteral administration include aqueous and non-aqueous isotonic sterile injections 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, and liposomes or other microparticulate systems which are designed to target the compound to blood components or one or more organs.
  • 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 injections, immediately prior to use.
  • Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.
  • Preferred unit dosage formulations are those suitable for administration either once daily or once or twice weekly as herein above recited, or an appropriate fraction thereof, of an active ingredient.
  • formulations of this invention may include other agents conventional in the art having regard to the type of formulation in question, for example, those suitable for oral administration may include such further agents as sweeteners, thickeners and flavouring agents.
  • the compound of formula (la) may also be presented for the use in the form of veterinary formulations, which may be prepared, for example, by methods that are conventional in the art.
  • Ganciclovir phosphonate in racemic form, may be prepared by methods that are known in the art of nucleoside synthetic chemistry for the preparation of the same or similar compounds, for example, PCT Patent Application WO 88/05438 and Prisbe , E.J., et. al., J. Med. Chem. (1986) 29: 671-675.
  • Resolution of R- and S-enantiomers can then be achieved by adding an enzyme, such as GMP kinase, which preferentially phosphorylates the R-enantiomer of racemic ganciclovir phosphonate.
  • the phosphorylated R-enantiomer may be separated from the S-enantiomer chromatographically and then dephosphorylated with a phosphatase enzyme, such as alkaline phosphatase.
  • a phosphatase enzyme such as alkaline phosphatase.
  • Hog brain GMP kinase is commercially available from Sigma Chemical Company, St. Louis, MO 63178 and calf intestine alkaline phosphatase may be obtained from Boehringer Mannheim Biochemicals, Indianapolis, IN 46250.
  • R-ganciclovir phosphonate (la) may be prepared by deesterification of a corresponding phosphono diester of formula (II)
  • both R groups are independently selected from straight or branched chain alkyl (eg., n-propyl, t-butyl, n-butyl), alkoxyalkyl (eg., methoxymethyl), acyloxyalkyl (eg., acetoxymethyl), alkenyl (eg., 2-butenyl), arylalkyl (eg., benzyl), aryloxyalkyl (eg., phenoxymethyl), aryl (eg.,phenyl optionally substituted by halogen, C 1-4 alkyl or C 1-4 alkoxy).
  • alkyl eg., n-propyl, t-butyl, n-butyl
  • alkoxyalkyl eg., methoxymethyl
  • acyloxyalkyl eg., acetoxymethyl
  • alkenyl eg., 2-butenyl
  • arylalkyl eg.,
  • the above deesterification process may be effected either in one step using conventional methods or stepwise via the corresponding mono-ester using any combination of standard deesterification methods such as chemical hydrolysis, for example, treatment with base, or enzymic hydrolysis eg., treatment with an esterase enzyme, for instance snake venom phosphodiesterase.
  • standard deesterification methods such as chemical hydrolysis, for example, treatment with base, or enzymic hydrolysis eg., treatment with an esterase enzyme, for instance snake venom phosphodiesterase.
  • L is a suitable leaving group such as a halo group, for example, iodo or bromo, or an organosulphonyloxy group, for example, methanesulphonyloxy or 4-toluenesulphonyloxy;
  • -OQ is a protected hydroxyl group such as an alkyl-, aryl-, or arylalkyl ether, for example, benzyl ether or a silylether group, for example, a trimethylsilyloxy-, or t-butyldiphenylsilyloxy group, or an ester, for example, nonanoyl or benzoyl ester, or a carbamate, for example, N,N-diphenyl carbamate.
  • an alkyl-, aryl-, or arylalkyl ether for example, benzyl ether or a silylether group, for example, a trimethylsilyloxy-, or t-butyldiphenylsilyloxy group, or an ester, for example, nonanoyl or benzoyl ester, or a carbamate, for example, N,N-diphenyl carbamate.
  • Q 1 is an amine protecting group, such as an acyl group, for example C 1-4 alkylcarbonyl, for instance acetyl, or a dialkylaminoalkylene group, for example, diC 1-4 alkylaminoC 1-4 alkylene, for instance, N,N-dimethylaminomethylene, or an alkoxycarbonyl group, for example, tert-butoxycarbonyl; and -OQ 2 is a protected hydroxyl group, such as an ether, for example, a silyl ether (for instance tert-butyldiphenylsilyl ether, triphenylsilyl ether or tert-butyldimethylsilyl ether), a straight or branched chain alkyl ether, a tetrahydropyranyl ether or an optionally substituted aryl ether (for instance benzylether, trityl ether or
  • 4-methoxybenzyl ether or as an ester, for example, an alkyl ester, cycloalkyl ester or optionally substituted aryl ester, or as a carbonate, for example, an alkyl or arylalkyl carbonate (for instance, methyl, isobutyl or benzyl carbonate); with the anion of the appropriate disubstituted phosphite of formula (IV)
  • L is a precursor of L, such as an alternative leaving group, for example, chloro-, or an organosulphonyloxy group, such as methanesulphonyloxy or 4- toluenesulphonyloxy; so as to convert L 1 into L and/or to effect the migration of the side chain from N-7 to N-9.
  • an alternative leaving group for example, chloro-
  • an organosulphonyloxy group such as methanesulphonyloxy or 4- toluenesulphonyloxy
  • This may be effected by heating a compound of formula (Va), (Vb) or a mixture thereof in polar solvent, such as, methyl ethyl ketone or acetone in the presence of an appropriate reagent to introduce L, for example, when L is iodo, an Iodide salt may be used, for instance sodium iodide; or by heating a compound of formula (Va), (Vb) or a mixture thereof in a non-polar solvent, such as benzene or dichloromethane in the presence of a silylating agent, such as N,0-bis(trimethylsilyl) acetamide, and a Lewis acid, such as trimethylsilyltriflate or tin tetrachloride.
  • polar solvent such as, methyl ethyl ketone or acetone
  • an Iodide salt may be used, for instance sodium iodide
  • a non-polar solvent such as benzene or dichloromethane
  • L 2 is an acid labile substituent such as an alkyl ether, for example C 1-4 alkoxy (eg. methoxy), or an acyloxy group, for example, acetoxy.
  • L 2 may be a leaving group, such as a halo group, for example, chloro or bromo; with a suitably protected and/or activated guanine derivative.
  • the guanine derivative may be prepared from commercially available starting materials using conventional techniques well known to those skilled in the art.
  • L 1 and -OQ 2 are as defined for formulae (Va) and (Vb), or an activated form thereof;
  • L 2 is an alkyl ether, typically methoxy
  • L 3 is either the same as L 2 or is a leaving group, such as a halo group, typically chloro-, using conventional techniques well known to those skilled in the art.
  • Q 3 and Q 4 may be the same or different and are hydroxyl protecting groups such as those described above, or together form a diol protecting group such as an acetonide, methylene acetal or benzylidine acetal.
  • the above conversion may be effected by initial treatment with aqueous acid, such as hydrochloric, acetic, tosic or trifluoroacetic acid, followed by oxidative cleavage of the resulting diol with sodium periodate in water or an alcoholic solvent, such as methanol or ethanol, or with lead tetraacetate in an organic solvent.
  • Reduction of the resulting aldehyde may be effected by a variety of techniques well known to those skilled in the art, including use of sodium borohydride in an alcoholic solvent such as methanol or ethanol.
  • L-Arabinose was dried under vacuum in the presence of P 2 O 5 for 72 h.
  • a total of 25 g (166 mmol) of L-arabinose was weighed into a flame dried round bottom flask fitted with a stirring bar and gas inlet adapter.
  • Imidazole 25 g, 367 mmol
  • DMF N,N-diraethylformamide
  • This solution was stirred at ambient temperature until the solids had dissolved.
  • tert-Butylchlorodiphenylsilane 50 g, 182 mmol
  • the reaction was heated at 60°C, under nitrogen, for two hours.
  • the DMF was then removed under vacuum at 60°C over a period of two hours.
  • the resulting thick yellow oil was dried on the vacuum pump.
  • H-4, J 7.0Hz), 3.90-3.83 (m, 2H, H-5), 1.32 (s, 3H, C(CH 3 ) 2 ), 1.29 (s, 3H, C(CH 3 ) 2 ), 1.05 (s, 9H, C(CH 3 ) 3 );
  • Phosphorous pentoxide 7.0 g (49.3 mmol) was weighed into a dry round bottom flask and treated with chloroform pre-dried with phosporous pentoxide. Dimethoxymethane was added and the solution was stirred at ambient temperature for 15 minutes. A total of 1.38 g (3.8 mmol) of (R)-1-0-(tert-butyldiphenylsilyl)- 4-chloro-1,2-butanediol was dissolved in dry chloroform and added to the reaction mixture. This solution was stirred for 24 hours at ambient temperature. The reaction mixture was decanted from the phosporous pentaoxide and the solids were washed with chloroform (2 x 50 mL).
  • Diacetylguanine 0.35g (1.4 mmol) (U.S. 4,355,032) was treated with N,0-bistrimethylsilylacetamide 1.8 mL (7.3 mmol) in 1,2- dichloroethane (10 mL). The solution was stirred for 1.5 hours until all the solids had dissolved. The 1,2-dichloroethane was removed under vacuum, and the residue was taken up in anhydrous acetonitrile.
  • the white solid residue weighed 0.26 g after drying. This material was taken up in 10 mL of 50 mM NaHCO 3 buffer (pH 9) and 100 units of snake venom phosphodiesterase I (Pharmacia LKB Biotechnology, Uppsala, Sweden) were added. This solution was incubated at 37°C for five days. HPLC on a SAX column with isocratic 10 mM ammonium phosphate showed the reaction was 50% complete. An additional 100 units of enzyme were added and the reaction was kept at 37°C for 41 hours more. HPLC showed the reaction was 65% complete.
  • UV ⁇ max ( ⁇ ): pH 7.00: 252.0 nm (12,100), 270 nm (9,500); 0.1 N HCl: 255.0 (10,900), 275 (8,300); 0.1N NaOH: 265.0 (10,000); 1 H-NMR (D 2 O) ⁇ , 7.78 (s.1H, H-8), 5.40 (br.s, 2H, NCH 2 O), 3.55 - 3.32 (m, 4H, H-3 and H-4), 1.56-1.46 (m, 2H, H-2), 1.32 - 1.13 (m, 2H, H-1);
  • UV ⁇ max ( ⁇ ): pH 7.00: 238nm(10,000), 261nm(10,000), 280 sh (6700);
  • a two phase system consisting of 240 mL of 50% aqueous sodium hydroxide, 4.89 g (0.014 M)tetra-n-butylammonium hydrogensulfate and 150 mL (1.92 M) of epichlorohydrin was stirred at room temperature for ten min.
  • Anhydrous benzyl alcohol, 36 mL (0.36 M) was then added and the resulting mixture stirred at room temperature for 4 h (after 3.5 h, a temperature increase to 50°C was noted).
  • reaction mixture was then sealed and the reaction flask was packed in a styrofoam container packed with dry ice and allowed to stand for 20 h (at -66°C).
  • the reaction mixture was quenched with saturated NaHCO 3 solution (100 mL) and the resulting suspension was allowed to warm to room temperature.
  • the THF was removed in vacuo to afford a concentrate which was extracted with CH 2 Cl 2 (2 x 350 mL).
  • the combined organic layers were filtered through a pad of celite, dried over MgSO 4 and then filtered again through a pad of celite.
  • the column was eluted with H 2 O and then a linear gradient from 0 to 0.2 N NH 4 HCO 3 , collecting fractions.
  • the product-containing fractions were pooled and concentrated in vacuo.
  • the concentrate was dissolved in H 2 O (3 mL) and applied to a Regis C-18 HPLC column (21 x 250 mm).
  • the product-containing fractions were pooled and concentrated in vacuo to a white amorphous solid. This solid was dissolved in H 2 O and lyophilized to provide 74 mg of the title compound as a white fluffy solid.
  • the column was eluted with H 2 O and then with a linear gradient from 0 to 0.4 N NH 4 HCO 3 , collecting fractions.
  • the product-containing fractions were pooled and concentrated in vacuo to a white solid.
  • An HPLC analysis of this solid (using the same conditions described above) again revealed the presence of a more nonpolar impurity.
  • the solid was dissolved in H 2 O (4 mL) and loaded onto a Regis C-18 prep column (21 x 250 mm). The column was eluted at 10 mL/min with H 2 O, collecting fractions.
  • the fractions were analyzed by HPLC (Supelco C-18, 2 mL/min, 100% H 2 O).
  • fractions containing the desired product were homogeneous, containing a single component which eluted at 48 seconds. These fractions were pooled and concentrated in vacuo and then lyophilized to furnish 28 mg of the title compound as a white fluff.
  • a reaction mixture contained 0.11 mmol racemic phosphonate of Example 2F, 1.2 mmol adenosine 5'- triphosphate, 1 mmol magnesium chloride and 14 units of hog brain GMP kinase (Sigma Chemical Company, St. Louis, MO 63178). After about 4 h at 37° C, the reaction mixture was frozen. Separation of the reaction products was performed using anion exchange chromatography on DE4AE Sephadex A-25: the reaction mixture was thawed, diluted to 70 ml with water, and applied to a chromatography column containing about 50 ml of DEAE Sephadex A-25 which had been previously equilibrated in 50 mM ammonium bicarbonate.
  • the column was washed with one liter of 50 mM ammonium bicarbonate, and compounds were eluted with 1.2 liters of a linear gradient of 50 - 500 mM ammonium bicarbonate.
  • the unreacted S-enantiomer (fraction 1) eluted first, followed by the monophosphate of the R-phosphonic acid (fraction 2), which was overlapped by the later-eluting adenosine 5'-diphosphate and adenosine 5' -triphosphate.
  • Fractions containing each enantiomer were pooled and dried in vacuo to remove water and ammonium bicarbonate.
  • Fraction 1 was determined to be a mixture of the S-enantiomer of the N-9-isomer (title compound) and a racemic mixture of the R- and S- N-7-isomers (0.052 mmol).
  • N-7 isomers may have contributed to the variations in optical rotation from the expected equal and opposite values to those of Example 3B.
  • 3 1 P NMR (D 2 O) ⁇ , 25.2 (s)
  • the monophosphate of the R-phosphonic acid (fraction 2 of Example 3A) (0.05 mmol), was treated with 5,600 units alkaline phosphatase from calf intestine (Boehringer Mannheim Biochemicals, Indianapolis, IN 46250) for one hour at 37° C.
  • the adenosine 5'-diphosphate and adenosine 5'-triphosphate were converted to adenosine, and the monophosphate of the R-phosphonic acid was converted to the title compound.
  • This mixture was chromatographed using DEAE Sephadex, as in Example 3A. Fractions containing the title compound were pooled and dried in vacuo to remove water and ammonium bicarbonate (0.047 mmol).
  • Example 3A Fraction 2 of Example 3A (39 ⁇ mol) was incubated for 24 hours at 37oC with creatine phosphate (5.6 mM), magnesium acetate (61 mM) and creatine kinase, (Boehringer Mannheim, rabbit muscle), 1,350 IU/ml (57 mM). The resulting mixture was purified on DEAE Sephadex by the method described in Example 3A to afford the title compound (25 ⁇ mol).
  • Example 3A The title compound of Example 3A (9.6 ⁇ mol) was dried from triethylammonlum bicarbonate then co-evaporated twice with acetonitrile. The compound was dissolved in 0.2 ml 1,3-dimethyl- 3,4,5,6,-tetrahydro-2(1H)-pyrlmidinone (Aldrich) then 0.012 g 1,1' -carbonyldiimldazole (Aldrich) was added. This mixture was stirred overnight at room temperature. Methanol (0.01 ml) was added and stirring continued for a further 30 min.
  • Tributylammonium pyrophosphate (Sigma, 0.046 g) was added, stirred 90 min at 44oC, then 1 ml water and 0.1 ml 1M sodium bicarbonate was added. This mixture was chromatographed on DEAE Sephadex as described in Example 3A. The fractions containing the title compound were combined and dried in vacuo to remove water and ammonium bicarbonate affording the desired product (3.2 ⁇ mol).
  • the "Active Ingredient” may be a compound of formula (la) or a pharmaceutically acceptable salt, ester or salt of such ester thereof.
  • formulations A, B and C are prepared by wet granulation of the ingredients with a solution of povidone, followed by addition of magnesium stearate and compression.
  • formulations, D and E are prepared by direct compression of the admixed ingredients.
  • the lactose in formulation E is of the direct compression type (Dairy Crest - "Zeparox").
  • 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. mg/tablet
  • a capsule formulation is prepared by admixing the ingredients of Formulation D in Example 5 above and filling into a two-part hard gelatin capsule.
  • Formulation B (infra) is prepared in a similar manner.
  • Capsules of Formulation D are prepared by dispersing the active Ingredient in the lecithin and arachis oil and filling the dispersion into soft, elastic gelatin capsules.
  • the following controlled release capsule formulation is prepared by extruding ingredients a, b and c using an extruder, followed by spheronization of the extrudate and drying. The dried pellets are then coated with release-controlling membrane (d) and filled into a two-piece, hard gelatin capsule.
  • the active ingredient is dissolved in most of the water (35°C-40°C) and the pH adjusted 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 10 mL amber glass via (type 1) and sealed with sterile closures and overseals.
  • the active ingredient is dissolved in the glycofurol.
  • the benzyl alcohol is then added and dissolved, and water added to 3 mL.
  • the mixture is then filtered through a sterile micropore filter and sealed in sterile 3 mL amber glass vials (type 1).
  • the active ingredient is dissolved in a mixture of the glycerol and most of the purified water.
  • An aqueous solution of the sodium benzoate is then added to the solution, followed by addition of the sorbitol solution and finally the flavour.
  • the volume is made up with purified water and mixed well.
  • Witepsol H15 is melted in a stem-jacketed pan at 45oC maximum.
  • the active ingredient is sifted through a 200 ⁇ m sieve and added to the molten base with mixing, using a Silverson fitted with a cutting head, until smooth dispersion is achieved. Maintaining the mixture at 45oC, the remaining Witepsol H15 is added to the suspension and stirred to ensure a homogenous mix.
  • the entire suspension is passed through a 250 ⁇ M stainless steel screen and, with continuous stirring, is allowed to cool to 40oC. At a temperature of 38oC to 40oC, 2.02 g of the mixture is filled into suitable, 2 mL plastic moulds. The suppositories are allowed to cool to room temperature.
  • the antiviral activities of the compounds of formulae (la) and (1b) and of racemic ganciclovir phosphonate were assessed against human cytomegalovirus (HCMV) , laboratory strain AD169.
  • the assay was conducted, in triplicate, in MCR-5 lung fibroblasts (Whittaker Bioproducts, Inc., Walkersville, MD) using the DNA hybridization assay developed by Diagnostic Hybrids, Inc., Athens, OH (Dankner, W.M., et.al, 1990, J. Virol. Methods, 28:293-298) with ganciclovir as a control.
  • the data indicates that the R-enantiomer of ganciclovir phosphonate is unexpectedly more potent than the S-enantiomer.
  • the R-enantiomer of ganciclovir phosphonate has twice the activity of racemic ganciclovir phosphonate.
  • the compound of formula (la) was tested for toxicity in human bone marrow progenitor cells, in vitro, by the methods of Dornsife, R.E. et.al., 1991, Antimicrob. Agents. Chemother., 35:322-328. Three separate assays were performed using marrow from three different donors.
  • R-enantiomer 100 ⁇ 10 120 ⁇ 10 50% Inhibition of bone marrow progenitor cells.

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Abstract

La présente invention se rapporte à un dérivé de phosphonate antiviral d'un analogue de nucléoside de purine acyclique, à des dérivés pharmaceutiquement acceptables, ainsi qu'à leur utilisation en thérapie médicale, en particulier pour le traitement d'infections par cytomégalovirus. Des procédés de préparation de l'énantiomère-R du composé de l'invention, lequel est pratiquement dépourvu de l'énantiomère-S correspondant, sont également décrits.
PCT/GB1992/001748 1991-09-24 1992-09-23 Nucleosides a usage therapeutique WO1993006112A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997041133A1 (fr) * 1996-04-29 1997-11-06 Sri International Analogues nucleotidiques de 2-aminopurine phosphonate enantiomeriquement purs utilises comme agents antiviraux

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130126A1 (fr) * 1983-06-24 1985-01-02 Merck & Co. Inc. (S)-(Dihydroxy-2,3 propoxy-1 méthyl)-9 guanine et ses dérivés acylés, leur préparation et leur application comme agents antiherpétiques
WO1988005438A1 (fr) * 1987-01-20 1988-07-28 Sri International Agents antiviraux
EP0452935A1 (fr) * 1990-04-20 1991-10-23 Institute Of Organic Chemistry And Biochemistry Of The Academy Of Sciences Of The Czech Republic (Phosphonométhoxy)-2-propyl-guanines chirales comme agents anti-viraux

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130126A1 (fr) * 1983-06-24 1985-01-02 Merck & Co. Inc. (S)-(Dihydroxy-2,3 propoxy-1 méthyl)-9 guanine et ses dérivés acylés, leur préparation et leur application comme agents antiherpétiques
WO1988005438A1 (fr) * 1987-01-20 1988-07-28 Sri International Agents antiviraux
EP0452935A1 (fr) * 1990-04-20 1991-10-23 Institute Of Organic Chemistry And Biochemistry Of The Academy Of Sciences Of The Czech Republic (Phosphonométhoxy)-2-propyl-guanines chirales comme agents anti-viraux

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol. 110, no. 14, 1988, WASHINGTON, DC US pages 4672 - 4685 K.C.NICOLAOU 'Total Synthesis of Amphoteronolide B and Amphoterivin B. 1.Strategy and Stereocontrolled Construction of Key Building Blocks' *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997041133A1 (fr) * 1996-04-29 1997-11-06 Sri International Analogues nucleotidiques de 2-aminopurine phosphonate enantiomeriquement purs utilises comme agents antiviraux
US5877166A (en) * 1996-04-29 1999-03-02 Sri International Enantiomerically pure 2-aminopurine phosphonate nucleotide analogs as antiviral agents

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