This invention relates to new analogs or derivatives of nitrobenzylthioinosine, use of these new analogs of nitrobenzylthioinosine for the treatment of pain and various other diseases as well as pharmaceuticals comprising at least on new analog of nitrobenzylthioinosine.

The treatment of pain conditions is of great importance in medicine. There is currently a world-wide need for additional pain therapy. The pressing requirement for a target-oriented treatment of pain conditions which is right for the patient, which is to be understood as the successful and satisfactory treatment of pain for the patients, is documented in the large number of scientific works which have recently and over the years appeared in the field of applied analgesics or on basic research on nociception.

The facilitated, carrier-mediated transport of nucleosides across mammalian cell membranes can be inhibited by a number of ligands including nucleoside derivatives such as nitrobenzylthioinosine (NBTI), and non-nucleoside compounds including marketed substances such as

NBTi, 15 dipyridamole and dilazep. Such compounds contribute to the physiological actions of adenosine. Through their blockade of the transport protein they increase the extracellular concentration of adenosine. This increase in adenosine levels causes a more profound occupancy of adenosine receptors through which adenosine exerts many of its physiological effects. The high hydrophilicity of NBTI and other transport inhibitors, however, may hinder their penetration into the CNS, where adenosine is involved in e.g., counteracting neuropathic pain. An earlier study indicated that a nitro group preferably at the 4-position of the benzyl moiety in NBTI is a prime factor in determining the potency of inhibition of nucleoside transport in human erythrocytes (Paul, B.; Chen, M. F.; Paterson, A. R. P. J. Med. Chem. 1975, 18, 968-973; Baldwin, S. A.; Mackey, J. R.; Cass, C. E.; Young, J. D. Molecular Medicine Today 1999, 5, 216-224). To gain further information on the interaction of NBTI with the nucleoside transporter-associated binding site we systematically replaced a number of substituents at C6, C8 and N9. The prime aim was to provide substances with reduced polarity while maintaining substantial affinity for the transport protein.

Still, the underlying main object of the present invention was to find a substance useful in the treatment of pain but also other indications as well as pharmaceutical compositions for this treatment.

It has now been found that new derivatives of nitrobenzylthioinosine are surprisingly useful in the treatment of pain but also other indications.

The main object of the invention is therefore a derivative of nitrobenzylthioinosine according to formula I

, wherein Y is selected from H, OH, SH, F, Cl, Br, I, -CF3, -CHF2, -CH2F, -OCH3, - OC2H5, -CH3, -C2H5;

R is selected from phenyl, benzyl, heteroaryl, or phenyl condensed with a heteroaryl, mono-or multisubstituted or unsubstituted respectively;

R' is selected from ribose, mono- or multisubstituted, C-ι-6-alkyl saturated or unsaturated, mono-or multisubstituted or unsubstituted; C3-8-cycloalkyl or C3-8-cycloalkyl containing 1 or 2 heteroatoms selected from S, O or N in the ring, mono-or multisubstituted or unsubstituted respectively; phenyl or benzyl, mono-or multisubstituted or unsubstituted respectively; or C1-6-alkyl-O-R'" with alkyl saturated or unsaturated, mono-or multisubstituted or unsubstituted and R'" selected from phenyl, heteroaryl, C3-8- cycloalkyl or C3-8-cycloalkyl containing 1 or 2 heteroatoms selected from S, O or N in the ring, mono-or multisubstituted or unsubstituted respectively;

R" is selected from NH-Ci-6-alkyl, NH-aryl, NH-heteroaryl, NH-C3-8- cycloalkyl, NH-Ci-3-alkyl-aryl, NH-Ci.3-alkyl-heteroaryl, N(C1-6-alkyl)2, N(Ci-3-alkyl-aryl)2, N(Ci-3-alkyl-heteroaryl)2, piperidine, piperazine, morpholine, pyrrolidine, mono- or multisubstituted respectively,

optionally in the form of its racemate, pure stereoisomers, especially enantiomers or diastereomers or in the form of mixtures of stereoisomers, especially enantiomers or diastereomers, in any suitable ratio; in the form shown or in form of the acid or base or in form of a salt, especially a physiologically acceptable salt, or in form of a solvate, especially a hydrate. These derivatives of nitrobenzylthioinosine are surprisingly effective in the treatment of pain and in other indications. Inhibitors of nucleoside transport have a potential as drugs enhancing adenosine's actions in the CNS. As such their use is in the treatment of chronic and/or neuropathic pain, epilepsy and other CNS-related disorders. Currently available ligands are often very hydrophilic, preventing substantial passage of the blood-brain barrier. In this invention the derivatives according to the invention show decreased hydrophilicity. Many compounds proved to have affinities in the nanomolar range with the substantial reduction in polarity achieved being promising to have more favorable characteristics in aspects of absorption and distribution.

In the sense of this invention alkyl- or cykloalkyl means saturated or unsaturated (but not aromatic), branched, unbranched and cyclic carbohydrates that are unsubstituted monosubstituted or multisubstituted. d-2-alkyl denominates C1- or C2-alkyl; Ci-3-alkyl C1-, C2- or C3-alkyl; C1-4- alkyl C1-, C2-, C3- or C4-alkyl; C1-5-alkyl C1-, C2-, C3-, C4- or C5-alkyl; Ci- 6-alkyl C1-, C2-, C3-, C4-, C5- or C6-alkyl; C1-7-alkyl C1-, C2-, C3-, C4-, C5- , C6- or C7-alkyl; C1-8-alkyl C1-, C2-, C3-, C4-, C5-, C6-, C7- or C8-alkyl; Ci-10-alkyl C1-, C2-, C3-, C4-, C5-, C6-, C7-, C8,- C9- or C10-alkyl; and Ci- 18-alkyl C1-, C2-, C3-, C4-, C5-, C6-, C7-, C8,- C9-, C10-, C11-, C12-, C13-, C14-, C15-, C16-, C17- oder C18-alkyl. Further C3-4-cycloalkyl denominates C3- or C4-cycloalkyl; C3-5-cycloalkyl C3-, C4- or C5-cycloalkyl; C3-6- cycloalkyl C3-, C4-, C5- or C6-cycloalkyl; C3.7-cycloalkyl C3-, C4-, C5-, C6- or C7-cycloalkyl; C3-8-cycloalkyl C3-, C4-, C5-, C6-, C7- or C8-cycloalkyl; C4-5-cycloalkyl C4- or C5-cycloalkyl; C4-6-cycloalkyl C4-, C5- or C6- cycloalkyl; C4-7-cycloalkyl C4-, C5-, C6- or C7-cycloalkyl; C5-6-cycloalkyl C5- or C6-cycloalkyl; and C5-7-cycloalkyl C5-, C6- oder C7-cycloalkyl. In regard to cycloalkyl cycloalkyl covers also saturated cycloalkyls, in which 1 or 2 carbonatoms are substituted by a heteroatom, S, N oder O. Cycloalkyl also covers once or multi unsaturated residues as long as cycloalkyl does not represent an aromatic system. Preferably alkyl or cycloalkyl methyl, ethyl, vinyl (ethenyl), propyl, allyl (2-propenyl), 1-propinyl, methylethyl, butyl, 1- methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1 ,1-dimethylpropyl, 1 ,2-dimethylpropyl, 2,2-dimethylpropyl, hexyl, 1-methylpentyl, cyclopropyl, 2-methylcyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, cyclopentylmethyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, CHF2, CF3, CH2OH, pyrazolinone, oxopyrazolinon, [1 ,4]dioxane or dioxolane.

In connection with alkyl and cycloalkyl, if not defined otherwise, the term "substituted" within the context of the present invention is understood to mean the replacement of an hydrogen atom by F, Cl1 Br, I, NH2, SH or OH, and the expression "multiply substituted" radicals is understood to mean that the substitution takes place multiply with the same or different substituents on different as well as on the same atoms, for example triple substitution on the same C atom as in the case of CF3 or at different positions as in the case of -CH(OH)-CH=CH-CHCb. Particularly preferred substituents in this connection are F, Cl and OH.

The term (CH2)3-6 is understood to denote -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-CH2- and -CH2-CH2-CH2-CH2- CH2-CH2-, and the term (CH2)1-4 is understood to denote -CH2-, -CH2-CH2-, -CH2-CH2-CH2- and -CH2-CH2-CH2-CH2-, etc.

The term aryl radical is understood to mean ring systems with at least one aromatic ring but without heteroatoms in also only one of the rings. Examples are phenyl, naphthyl, fluoranthenyl, fluorenyl, tetralinyl or indanyl, in particular 9H-fluorenyl or anthracenyl radicals, which may be unsubstituted or singly or multiply substituted.

The term heteroaryl radical is understood to mean heterocyclic ring systems with at least one unsaturated ring, which contain one or more heteroatoms from the group comprising nitrogen, oxygen and/or sulfur, and which may also be singly or multiply substituted. Examples of the group of heteroaryls that may be mentioned include furan, benzofuran, thiophene, benzothiophene, pyrrole, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phthalazine, benzo-1 ,2,5-thiadiazole, benzothiazole, indole, benzotriazole, benzodioxolane, benzodioxane, carbazole, indole and quinazoline.

In this connection the term substituted in connection with aryl and heteroaryl is understood to denote the substitution of the aryl or heteroaryl with R23, OR23, a halogen, preferably F and/or Cl, a CF3, a CN, an NO2, an NR24R25, a C-i-6-alkyl (saturated), a Ci-6-alkoxy, a C3-8-cycloalkoxy, a C3-8- cycloalkyl or a C2-6-alkylene.

In this connection the radical R23 denotes H, a C-i-io-alkyl radical, preferably a C-ι-6-alkyl radical, an aryl or heteroaryl radical or an aryl or heteroaryl radical bonded via a C1-3-alkylene group, wherein these aryl and heteroaryl radicals may not themselves be substituted by aryl or heteroaryl radicals,

the radicals R24 and R25, which are identical or different, denote H, a CMO- alkyl radical, preferably a Ci-6-alkyl radical, an aryl radical, a heteroaryl radical or an aryl or heteroaryl radical bonded via a Ci-3-alkylene group, wherein these aryl and heteroaryl radicals may not themselves be substituted by aryl or heteroaryl radicals,

or the radicals R24 and R25 together denote CH2CH2OCH2CH2, CH2CH2NR26CH2CH2, or (CH2)3-6, and

the radical R26 denotes H, a C-i_iO-alkyl radical, preferably a Ci-6-alkyl radical, an aryl or heteroaryl radical, or an aryl or heteroaryl radical bonded via a Ci_3-alkylene group, wherein these aryl and heteroaryl radicals may not themselves be substituted with aryl or heteroaryl radicals. The term salt is understood to mean any form of the active constituent according to the invention in which this adopts an ionic form or is charged and is coupled to a counterion (a cation or anion), and is present in solution. The term is also understood to include complexes of the active constituent with other molecules and ions, in particular complexes that are complexed via ionic interactions.

The term physiologically compatible salt with cations or bases is understood within the context of the present invention to mean salts of at least one of the compounds according to the invention - generally of a (deprotonated) acid - as an anion of at least one, preferably inorganic cation, that are physiologically compatible, especially when used in humans and/or mammals. Particularly preferred are the salts of alkali and alkaline earth metals, but also with NH4+, and in particular (mono) or (di)sodium, (mono) or (di)potassium, magnesium or calcium salts.

The term physiologically compatible salt with anions or acids is understood within the context of the present invention to mean salts of at least one of the compounds according to the invention - generally protonated, for example on the nitrogen atom - as a cation with at least one anion, that are physiologically compatible, especially when used in humans and/or mammals. In the context of the present invention the term is particularly understood to denote the salt formed with a physiologically compatible acid, namely salts of the respective active constituent with inorganic or organic acids, that are physiologically compatible, especially when used in humans and/or mammals. Examples of physiologically compatible salts of specific acids are salts of: hydrochloric acid, hydrobromic acid, sulfuric acid, methanesulfonic acid, formic acid, acetic acid, oxalic acid, succinic acid, tartaric acid, mandelic acid, fumaric acid, lactic acid, citric acid, glutamic acid, 1 ,1-dioxo-1 ,2-dihydro1λ6-benzo[d]isothiazol-3-one (saccharinic acid), monomethylsebacic acid, 5-oxoproline, hexane-1- sulfonic acid, nicotinic acid, 2-, 3- or 4-aminobenzoic acid, 2,4,6- trimethylbenzoic acid, α-lipoic acid, acetylglycine, hippuric acid and/or aspartic acid. The hydrochloride salt is particularly preferred.

In a preferred embodiment of a derivative according to the invention R is selected from phenyl, benzyl or phenyl condensed with a heteroaryl, mono- or multisubstituted or unsubstituted respectively,

preferably selected from phenyl, benzyl or phenyl condensed with a heteroaryl, unsubstituted or mono- or disubstituted with OH, F, Cl, Br, I, -CF3, -OCH3, -OC2H5, -CH3, -C2H5,

especially selected from 4-nitrophenyl, benzo[1 ,2,5]oxadiazole or unsubstituted phenyl.

In a preferred embodiment of a derivative according to the invention R1 is selected from

n-butyl or butan-4-ol; cyclopentyl, tetrahydrofuranyl or tetrahydropyranyl, unsubstituted respectively; benzyl, unsubstituted or mono- or disubstituted with NO2, F, phenyl, I, Cl, trifluoromethoxy, trifluoromethyl or methoxy; or -butyl-O-tetrahydropyranyl,

preferably denotes benzyl.

In a preferred embodiment of a derivative according to the invention R" is selected from NH-Ci_6-alkyl, NH-C3-8-cycloalkyl, N(Ci-6-alkyl)2, piperidine, morpholine or pyrrolidine, mono- or multisubstituted respectively, preferably NH-C-ι-6-alkyl, NH-Cs-e-cycloalkyl, piperidine, morpholine or pyrrolidine.

In a preferred embodiment of a derivative according to the invention Y denotes H. In a preferred embodiment the derivative is selected from the following group:

9-Benzyl-8-(cyclopentylamine)-6-(4-nitrobenzyl)-6-mercapt opurine 9-Benzyl-8-(cyclohexylamine)-6-(4-nitrobenzyl)-6-mercaptopur ine 9-Benzyl-6-(4-nitrobenzyl)-8-pyrrolidino-6-mercaptopurine 9-Benzyl-8-morpholino-6-(4-nitrobenzyl)-6-mercaptopurine 6-(Benzo[1 ,2,5]oxadiazol-5-ylmethylsulfanyl)-9-benzyl-8-pyrrolidin-1-y l-9H- purine 6-(Benzo[1 ,2,5]oxadiazol-5-ylmethylsulfanyl)-9-benzyl-8-morpholin-4-yl -9H- purine 9-Benzyl-6-benzylsulfanyl-8-morpholin-4-yl-9H-purine 9-Benzyl-6-benzylsulfanyl-8-pyrrolidin-1-yl-9H-purine

The derivatives of nitrobenzylthioinosine according to the invention are surprisingly effective in the treatment of pain and in other indications. Therefore, a further object of the invention is a pharmaceutical composition comprising at least one derivative of nitrobenzylthioinosine according to the invention as active ingredient as well as optionally at least one auxiliary material and/or additive.

The auxiliary material and/or additive can be selected from carrier, excipient, support materials, glidants, fillers, solvents, diluents, colorants, taste conditioners like sugars, antioxidants and/or binders. In the case of a suppository this might involve waxes or fatty acid esters or conserving agents, emulsifiers and/or carriers for parenteral application. The selection of these auxiliary materials and/or additives and of the amounts to be used depends upon how the pharmaceutical composition is to be applied.

Examples include here oral or parenteral like pulmonal, nasal, rectal and/or intravenous application. Therefore the pharmaceutical composition according to the invention can be adapted for topical or systemical application, especially dermal, subcutaneous, intramuscular, intra-articular and/or intraperitoneal, pulmonal, buccal, sublingual, nasal, percutaneous, vaginal, oral or parenteral, pulmonal, nasal, rectal and/or intravenous application.

For treatment the pharmaceutical composition according to the invention might preferrably be in the form of a plaster and/or gauze providing an occlusion of the burned or wounded skin.

For oral application preparations in the form of tablets, chewable tablets, dragees, capsules, granules, drops, juices and syrups are suitable. Solutions, suspensions, readily reconstitutable dry preparations and sprays are suitable i.a. for parenteral application. The compounds according to the invention as a deposit in a dissolved form or in a patch, optionally with the addition of agents which promote dermal penetration, are examples of suitable percutaneous forms of application. Dermal applications include i.a. an ointment, a gel, a cream, a lotion, a suspension, an emulsion whereas the preferred form for rectal application is a suppository. Therefore, in a preferred object of the invention the pharmaceutical composition according to the invention is in the form of an ointment, a gel, a cream, a lotion, a suspension, an emulsion, a suppository, a solution, a tablet, a chewable tablet, a dragee, a capsule, a granules, drops, a juice and/or a syrup.

The compounds according to the invention can be released in a delayed manner from forms of preparations which can be applied as mentioned above, especially orally, rectally or percutaneously. Retard formulations are preferred objects of the invention.

The amount of active ingredient to be administered to the patient varies depending on the weight of the patient, on the type of application, on the indication and on the severity of the illness. 1 to 500 mg of the active ingredient are usually applied per kg.

A further preferred object of the invention are pharmaceutical compositions containing at least 0,05 bis 90,0 % of active ingredient.

The derivatives of nitrobenzylthioinosine according to the invention are surprisingly effective in the treatment of pain and in other indications. Therefore a further embodiment of the invention comprises the use of a derivative of nitrobenzylthioinosine according to the invention for the treatment of pain, especially acute, chronic and/or neuropathic pain.

A further embodiment of the invention comprises the use of a derivatives of nitrobenzylthioinosine according to the invention for the treatment of epilepsy and other CNS-related disorders as well as for neuroprotection or cardioprotection.

Furthermore the invention relates to a method of treatment using derivatives of nitrobenzylthioinosine according to the invention especially for the treatment of pain, especially acute, chronic and/or neuropathic pain; the treatment of epilepsy and other CNS-related disorders as well as for neuroprotection or cardioprotection.

The following examples shall further illustrate the invention without restricting the object of the invention.

Examples and Drawing

Column chromatography was performed on Baker Silica Gel (0.063-0.200 mm). For TLC analysis, Schleicher and Schuell F1500/LS 254 silica plates were used. Spots were visualised with ultraviolet light. Microwave reactions were performed in an Emrys™ Optimizer. 1H NMR and 13C NMR were recorded with a Bruker AC 200 spectrometer at room temperature unless indicated otherwise. Tetramethylsilane was used as internal standard; δ in ppm, J in Hz. Melting points were determined with a Bϋchi melting point apparatus and are uncorrected. High Resolution Mass spectroscopy was performed on a PE-Sciex API Qstar instrument. Scheme 1 :

— R1 = rib(OAc)3 ->■ R' = ribose General procedure A: To a solution of 2',3',5'-tri-O-acetyl-8-bromoinosine in dioxane (10 ml_ per mmol) was added the appropiate alkylamine (14 eq). After stirring for 3 days at 80°C the reaction mixture was evaporated to dryness. The residue was dissolved in dry pyridine and evaporated to dryness (two times). To a solution of the resulting residue in pyridine (3.5 mL per mmol) were added acetic acid anhydride (0.85 ml_ per mmol) and a catalytic amount of DMAP. The mixture was stirred for 4h before methanol was added (1.5 mL per mmol). After evaporation of the solvents the residue was dissolved in dichloromethane (20 mL per mmol) and the organic layer was washed with 10% NaHCO3 (10 mL per mmol) and water (10 mL per mmol). The organic layer was dried (MgSO4), filtered, and concentrated to dryness. Remaining pyridine was removed by coevaporation with toluene and dichloromethane. The product was purified by column chromatography (eluent: CH2CI2/MeOH, 100/0→95/5, v/v).

General procedure B: Per mmol of purine (3 x coevaporated with dry pyridine) in 25 mL of dry pyridine was added 1.75 g of phosphorous pentasulfide and the resulting mixture was refluxed for 7h. After evaporation of the solvent the residual solvent was removed by coevaporation with MeOH (2 x). Water was added and the resulting mixture was stirred for 1h at 500C. After extraction with EtOAc (3 x 15 mL), the combined organic layers were dried (Na2SO4), filtrated, and the solvent was evaporated. The product was purified by column chromatography (eluent: EtOAc/MeOH, 97/3→95/5 v/v).

General procedure C: Per mmol of substituted purine in 7.5 mL of dry DMF was added 1 eq. of K2CO3 and 1.2 eq. of RCH2Br. After stirring overnight at r.t. 10 mL of water was added, the mixture extracted with EtOAc (3 x 10 mL), the combined organic layers washed with brine (15 mL), dried (Na2SO4), filtered, and the solvent was evaporated. The product was purified by column chromatography (eluent: EtOAc/PE 40-60, 1/1 -»6/4 v/v).

General procedure D: Per mmol of purine 25 mL of MeOH saturated with NH3 was added at 0°C. After stirring overnight the solvent was evaporated and the product purified by column chromatography (eluent: EtOAc/MeOH, 95/5->90/10 v/v). The appropriate fractions were collected and evaporated to dryness. Residual EtOAc was removed by dissolving the product in CH2CI2 followed by evaporation (two times).

General procedure E: Per mmol of purine were added 6 mL of dioxane and 2.4 mL of water followed by 7.5 eq. of the required amine. The mixture was heated in an Emrys™ Optimizer microwave for 5h at 1750C or 2.5h at 15O0C. After removal of the solvents by evaporation dioxane was added and the mixture evaporated to dryness. The product was purified by column chromatography (eluent: CH2CVMeOH, 99/1→90/10 v/v).

6-Benzylthioinosine This compound was prepared according to a literature procedure (Fleming, S.A.; Rawlins, D. B.; Samano, V.; Robins, M.J. J. Org. Chem. 1992, 57, 5968-5976).

2\3I,5I-Tri-O-acetyl-inosine This compound was prepared according to a literature procedure (Roelen, H.; Veldman, N.; Spek, A.L.; von Frijtag Drabbe Kϋnzel, J.; Mathόt, R.A.A.; Uzerman, AP. J. Med. Chem. 1996, 39, 1463-1471).

2\3l,5'-Tri-0-acetyl-8-bromoinosine This compound was prepared according to a literature procedure (Roelen, H.; Veldman, N.; Spek, A.L.; von Frijtag Drabbe Kϋnzel, J.; Mathόt, R.A.A.; Uzerman, AP. J. Med. Chem. 1996, 39, 1463-1471).

2l,3',51-Tri-O-acetyl-8-(methylamino)-inosine This compound was prepared according to general procedure A applying methylamine (40% in H2O, 15 mL per mmol). Yield: 65 %. White solid. 1H NMR (CDCI3) δ 2.04, 2.15, 2.16 (3 x s, 3 x 3H, 3 x CH3CO), 3.11 (d, 3H, J = 4.9 CH3N), 4.26- 4.41 (m, 2H, H-4', 1 x H-5% 4.54-4.68 (m, 1 H, 1 x H-5% 5.09 (q, 1 H, J = 4.9, CH3NH), 5.46 (dd, 1 H, J = 3.8, J = 6.2, H-31), 5.71 (t, 1 H, J = 6.6, H-21), 6.18 (d, 1 H1 J = 6.8, H-11), 7.97 (s, 1 H, H-2), 11.55 (br s, 1 H, NH). 13C NMR (CDCI3) δ 19.9, 20.1 , 20.3, 29.5, 62.6, 69.6, 70.4, 79.9, 84.4, 121.9, 142.5, 148.0, 151.8, 157.6, 169.1 , 169.3, 169.8.

2I,3',5'-Tri-O-acetyl-8-(ethylamino)-inosine This compound was prepared according to a literature procedure (Roelen, H.; Veldman, N.; Spek, A.L.; von Frijtag Drabbe Kϋnzel, J.; Mathot, R.A.A.; Uzerman, AP. J. Med. Chem. 1996, 39, 1463-1471).

2",3',5I-Tri-O-acetyl-8-(fi-propylamino)-inosine This compound was prepared according to general procedure A applying n-propylamine (11.5 mL per mmol) and H2O (5 ml_ per mmol). Yield: 58 %. Yellowish foam. 1H NMR (CDCI3) δ 0.96 (t, 3H, J = 7.3, CH3CH2), 1.70 (sextet, 2H, J = 7.3, CH3CH2), 2.05, 2.13, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.35-3.67 (m, 2H, CH2N), 4.27-4.42 (m, 2H, H-4\ 1 x H-51), 4.51-4.63 (m, 1 H, 1 x H-51), 5.06 (t, 1 H1 J = 5.9, CH2NH), 5.48 (dd, 1 H, J = 4.0, J = 5.8, H-31), 5.79 (t, 1 H, J = 6.2, H-2), 6.12 (d, 1 H, J = 6.6, H-11), 7.92 (s, 1 H, H-2), 11.55 (br s, 1 H, NH). 13C NMR (CDCI3) δ 10.9, 19.8, 20.1 , 20.2, 22.2, 44.5, 62.6, 69.5, 70.5, 79.8, 84.5, 121.9, 142.1 , 147.9, 151.1 , 157.6, 169.1 , 169.2, 169.8.

2\3\5l-Tri-0-acetyl-8-(n-butylamino)-inosine This compound was prepared according to general procedure A applying n-butylamine. Yield: 47 %. Yellowish foam. 1H NMR (CDCI3) δ 0.96 (t, 3H, J = 7.3, CH3CH2), 1.29-1.69 (m, 2H, CH3CH2), 1.57-1.75 (m, 2H, CH2CH2N), 2.05, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.37-3.68 (m, 2H, CH2N), 4.27-4.41 (m, 2H, H-4\ 1 x H-5), 4.48-4.63 (m, 1H, 1 x H-5), 5.00 (t, 1 H, J = 5.9, CH2NH), 5.49 (dd, 1 H, J = 4.4, J = 5.9, H-31), 5.79 (t, 1 H, J = 6.2, H-2'), 6.11 (d, 1 H, J = 6.6, H-11), 7.91 (s, 1 H, H-2), 11.40 (br s, 1 H, NH). 13C NMR (CDCI3) δ 13.4, 19.7, 19.9, 20.1 , 20.3, 31.2, 42.6, 62.7, 69.6, 70.5, 79.9, 84.6, 122.0, 142.2, 148.0, 151.2, 157.7, 169.1 , 169.3, 169.8.

Z'^'^'-Tri-O-acetyl-S-tn-pentylaminoJ-inosine This compound was prepared according to general procedure A applying n-pentylamine. Yield: 81 %. Yellow foam. 1H NMR (CDCI3) δ 0.90 (t, 3H, J = 6.6, CH3CH2), 1.21- 1.47 (m, 4H, 2 x CH2), 1.56-1.79 (m, 2H, CH2CH2N), 2.05, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.35-3.68 (m, 2H, CH2N), 4.87-4.41 (m, 2H, H-4', 1 x H-5), 4.49-4.63 (m, 1 H, 1 x H-5), 5.03 (t, 1 H, J = 5.9, CH2NH), 5.49 (dd, 1 H, J = 4.4, J = 6.2, H-31), 5.80 (t, 1 H, J = 6.2, H-21), 6.12 (d, 1 H, J = 6.2, H-11), 7.97 (s, 1 H, H-2), 11.24 (br s, 1 H, NH). 13C NMR (CDCI3) δ 13.5, 19.8, 20.0, 20.1 , 21.9, 28.5, 28.7, 42.7, 62.6, 69.5, 70.5, 79.7, 84.5, 121.9, 142.0, 147.8, 151.1 , 157.5, 169.0, 169.1 , 169.7.

2',3',5I-Tri-0-acetyl-8-(n-hexylamino)-inosine This compound was prepared according to general procedure A applying />hexylamine. Yield: 43 %. Yellowish oil. 1H NMR (CDCI3) δ 0.89 (t, 3H, J = 6.6, CH3CH2), 1.21- 1.48 (m, 6H, 3 x CH2), 1.60-1.74 (m, 2H, CH2CH2N), 2.05, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.37-3.67 (m, 2H1 CH2N), 4.27-4.43 (m, 2H, H-4', 1 x H-51), 4.49-4.63 (m, 1 H, 1 x H-51), 5.03 (t, 1 H, J = 5.8, CH2NH), 5.51 (dd, 1 H, J = 4.2, J = 6.0, H-31), 5.80 (t, 1 H, J = 6.2, H-2\ 6.13 (d, 1H, J = 6.2, H-11), 7.98 (s, 1H, H-2), 11.12 (br s, 1H, NH). 13C NMR (CDCI3) δ 13.4, 19.7, 19.9, 20.0, 26.0, 28.8, 30.9, 42.7, 62.5, 69.4, 70.5, 79.6, 84.5, 121.9, 142.0, 147.7, 151.0, 157.4, 168.9, 169.1 , 169.6.

21,3',5'-Tri-0-acetyl-8-[(2-nniethyl-butyl)-amino]-inosin e This compound was prepared according to general procedure A applying 2-methyl- butylamine. Yield: 27 %. Colourless oil. 1H NMR (CDCI3) δ 0.87-0.99 (m, 6H, 2 x CH3), 1.05-1.28 (m, 1 H, CH3CHH), 1.39-1.62 (m, 1 H, CH3CHH), 1.69-1.90 (m, 1 H, CH3CH), 2.06, 2.11 , 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.17-3.34 (m, 0.5H, CHHNH), 3.36-3.46 (m, 1H, CHHNH), 3.47-3.66 (m, 0.5H, CHHNH), 4.28-4.61 (m, 3H, H-4\ H-5), 5.07 (t, 1 H, J = 5.9, NH), 5.46-5.55(m, 1H, H-3% 5.79-5.88 (m, 1H, H-2\ 6.07-6.15 (m, 1H, H-1% 7.99 (s, 1H, H-2). 13C NMR (CDCI3) δ 10.9, 16.7, 20.1 , 20.2, 20.4, 26.6, 26.8, 34.1 , 48.7, 62.8, 69.9, 70.7, 80.0, 84.7, 122.1 , 142.1 , 148.0, 151.4, 157.9, 169.2, 169.4, 169.9.

2",3',5I-Tri-0-acetyl-8-(cyclopropylamino)-inosine This compound was prepared according to general procedure A applying cyclopropylamine (1.7 ml_ per mmol) and H2O (3.5 ml_ per mmol). Yield: 57 %. Yellowish solid. 1H NMR (CDCI3) δ 0.51-0.68 (m, 2H, CH2CHN), 0.80-0.98 (m, 2H, CH2CHN), 2.05, 2.14, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 2.88-3.05 (m, 1 H, CHN), 4.29- 4.40 (m, 2H, H-4', 1 x H-51), 4.50 (ABX, 1 H, J = 4.8, J = 12.8, 1 x H-5% 5.41 (br s, 1 H, CH2CHNH), 5.50 (dd, 1H1 J = 4.8, J = 5.9, H-3% 5.75 (t, 1 H, J = 6.2, H-21), 6.10 (d, 1 H, J = 6.2, H-11), 8.05 (s, 1 H, H-2), 11.21 (br s, 1 H, NH). 13C NMR (CDCI3) δ 7.1 , 20.0, 20.2, 20.4, 24.8, 62.6, 69.5, 70.9, 79.7, 84.9, 122.0, 143.1 , 148.1 , 154.5, 157.7, 169.2, 169.3, 170.0.

2I,3',5'-Tri-O-acetyl-8-(cyclopentylamino)-inosine This compound was prepared according to a literature procedure (Roelen, H.; Veldman, N.; Spek, A.L.; von Frijtag Drabbe Kϋnzel, J.; Mathδt, R.A.A.; Uzerman, AP. J. Med. Chem. 1996, 39, 1463-1471 ).

2l,3\5'-Tri-O-acetyl-8-(cyclohexylamino)-inosine This compound was prepared according to general procedure A applying cyclohexylamine. Yield: 28 %. Colourless oil. 1H NMR (CDCI3) δ 1.07-1.84 (m, 8H, 2 x NHCHCHH, 3 x CH2), 2.06, 2.09, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 2.07- 2.25 (m, 2H, 2 x NHCHCHH), 3.87-4.08 (m, 1 H, CH2CHNH), 4.29-4.41 (m, 3H, H-4', H-51), 4.50 (ABX, 1H, J = 4.7, J = 12.8, 1 x H-51), 4.73 (d, 1H, J = 7.5, CH2CHNH), 5.53 (dd, 1 H, J = 4.6, J = 5.9, H-31), 5.88 (t, 1 H1 J = 5.9, H- 21), 6.03 (d, 1 H, J = 5.9, H-11), 7.91 (s, 1 H, H-2), 11.31 (br s, 1 H, NH). 13C NMR (CDCI3) δ 20.1 , 20.2, 20.5, 24.7, 25.4, 33.0, 33.2, 51.3, 62.7, 69.7, 71.0, 79.8, 84.9, 122.2, 141.9, 147.9, 150.6, 157.9, 169.3, 170.0.

2',3\51-Tri-O-acetyl-8-pyrrolidino-inosine This compound was prepared according to general procedure A applying pyrrolidine. Yield: 65 %. White foam. 1H NMR (CDCI3) δ 1.72-2.09 (m, 4H1 2 x CH2CH2N), 2.06, 2.08, 2.12 (3 x s, 3 x 3H, 3 x CH3CO), 3.52-3.75 (m, 4H, 2 x CH2N), 4.29-4.37 (m, 2H, H-4', 1 x H-51), 4.48 (ABX, 1 H, J = 6.0, J = 13.7, 1 x H-51), 5.86 (dd, 1 H, J = 5.1 , J = 5.9, H-31), 5.98 (d, 1 H, J = 4.9, H-11), 6.40 (dd, 1 H, J = 4.9, J = 5.9, H-21), 7.97 (s, 1H, H-2), 11.44 (br s, 1 H, NH). 13C NMR (CDCI3) δ 19.8, 19.9, 20.0, 25.0, 50.7, 62.4, 69.9, 71.1 , 79.0, 86.2, 122.5, 142.4, 147.8, 153.8, 157.4, 168.6, 168.8, 169.8.

2l,3",5l-Tri-O-acetyl-8-piperidino-inosine This compound was prepared according to general procedure A applying piperidine. Yield: 60 %. White solid. 1H NMR (CDCI3) δ 1.51-1.82 (m, 6H, (CH2)SCH2N), 2.07, 2.09, 2.13 (3 x s, 3 x 3H, 3 x CH3CO), 3.14-3.38 (m, 4H, 2 x CH2N), 4.28-4.38 (m, 2H, H-4', 1 x H-51), 4.51 (ABX, 1 H, J = 6.2, J = 13.9, 1 x H-51), 5.84-5.96 (m, 2H, H-V, H-31), 6.25 (dd, 1 H, J = 4.8, J = 6.2, H-21), 8.07 (s, 1 H, H-2), 11.50 (br s, 1 H, NH). 13C NMR (CDCI3) δ 19.9, 20.1 , 23.4, 24.9, 51.9, 62.5, 69.9, 71.5, 79.0, 86.2, 122.2, 143.8, 147.9, 155.2, 157.7, 168.6, 168.9, 169.9.

Z'.SSS'-Tri-O-acetyl-δ-W-morpholino-inosine This compound was prepared according to general procedure A applying morpholine. Yield: 40 %. White solid. 1H NMR (CDCI3) δ 2.06, 2.10, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 3.21-3.49 (m, 4H, 2 x CH2N), 3.77-3.95 (m, 4H, 2 x CH2O), 4.26- 4.55 (m, 3H, H-4', H-51), 5.85-5.94 (m, 2H, H-V, H-31), 6.29 (dd, 1 H, J = 4.6, J = 6.0, H-2% 8.10 (s, 1 H, H-2), 11.52 (br s, 1 H, NH). 13C NMR (CDCI3) δ 19.9, 20.0, 51.0, 62.4, 65.7, 69.9, 71.4, 79.1 , 86.1 , 122.1 , 144.1 , 147.9, 153.9, 157.5, 168.7, 168.9, 169.9.

2I,3',5'-Tri-O-acetyl-8-methylamino-thioinosine This compound was prepared according to general procedure B. Yield: 63 %. Yellow oil. 1H NMR (CDCI3) δ 2.03, 2.14, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.15-3.78 (d, 3H, J = 4.8, CH3N), 4.28-4.44 (m, 2H, H-4', 1 x H-51), 4.53-4.66 (m, 1 H, 1 x H-51), 5.45 (dd, 1 H, J = 4.0, J = 6.2, H-31), 5.59 (q, 1 H, J = 4.8, NH), 5.66- 5.76 (m, 1 H, H-21), 6.17 (d, 1H, J = 6.6, H-71), 8.11 (s, 1H, H-2). 13C NMR (CDCI3) δ 20.1 , 20.2, 20.4, 29.6, 62.7, 69.6, 70.7, 79.9, 84.9, 134.3, 142.6, 143.9, 153.7, 168.5, 169.4, 169.5, 170.1. MS (ESI) m/z Found: 440.1 [M + H]+, Calcd: 440.1. 2I,3',5I-Tri-O-acetyl-8-ethylamino-thioinosine This compound was prepared according to general procedure B. Yield: 67 %. Yellow solid. 1H NMR (CDCI3) δ 1.34 (t, 3H, J = 7.3, CH3CH2), 2.03, 2.13, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.56-3.78 (m, 2H, CH2N), 4.28-4.42 (m, 2H, H-4', 1 x H-5% 4.59 (dd, 1 H, J = 4.0, J = 12.1 , 1 x H-51), 5.29 (t, 1 H, J = 4.4, NH), 5.45 (dd, 1 H, J = 4.0, J = 6.6, H-31), 5.72 (t, 1 H, J = 6.6, H-2% 6.12 (d, 1 H, J = 6.6, H-11), 8.01 (s, 1H, H-2). 13C NMR (CDCI3/CD3OD 1/1 , v/v) δ 13.7, 19.3, 19.4, 19.6, 37.1 , 62.4, 69.9, 70.8, 79.2, 84.8, 134.7, 141.3, 143.4, 152.8, 168.8, 169.3, 169.5, 170.4. MS (ESI) m/z Found: 454.0 [M + H]+, Calcd: 454.1.

2',3",5I-Tri-O-acetyl-8-(/7-propylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 60 %. Brown oil. 1H NMR (CDCI3) δ 0.97 (t, 3H, J = 7.3, CH3CH2), 1.59-1.81 (m, 2H, CH3CH2), 2.03, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.42-3.75 (m, 2H, CH2N), 4.26- 4.45 (m, 2H, H-4', 1 x H-51), 4.58 (dd, 1 H, J = 4.0, J = 12.1 , 1 x H-51), 5.36 (t, 1 H1 J = 5.5, NH), 5.46 (dd, 1 H, J = 4.4, J = 6.6, H-3), 5.76 (t, 1 H, J = 6.6, H-2\ 6.14 (d, 1 H, J = 6.6, H- 1% 8.05 (s, 1 H, H-2), 11.67 (br s, 1 H, NH). 13C NMR (CDCI3) δ 10.8, 19.8, 20.1 , 20.5, 22.1 , 44.5, 62.5, 69.5, 70.5, 79.9, 84.6, 134.4, 142.0, 143.8, 152.8, 168.8, 169.0, 169.2, 169.8.

21,3',51-Tri-O-acetyl-8-(n-butylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 61 %. Yellow oil. 1H NMR (CDCI3) δ 0.94 (t, 3H, J = 7.3, CH3CH2), 1.30-1.50 (m, 2H, CH3CH2), 1.57-1.75 (m, 2H, CH2CH2NH), 2.04, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.46-3.77 (m, 2H, CH2N), 4.26-4.44 (m, 2H, H-4\ 1 x H-51), 4.58 (dd, 1H, J = 4.0, J = 12.1 , 1 x H-51), 5.30 (t, 1H1 J = 5.5, NH), 5.45 (dd, 1 H1 J = 4.0, J = 6.2, H-3% 5.76 (dd, 1H, J = 6.2, J = 6.6, H-2% 6.13 (d, 1 H, J = 6.6, H- 1% 8.04 (s, 1 H, H-2), 11.63 (br s, 1 H, NH). 13C NMR (CDCI3) δ 13.5, 19.7, 20.0, 20.2, 20.4, 31.2, 42.8, 62.7, 69.6, 70.6, 80.2, 84.6, 134.5, 142.1 , 144.0, 152.9, 168.8, 169.2, 169.4, 169.9. 21,3',5l-Tri-0-acetyl-8-(/7-pentylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 45 %. Yellow-brown foam. 1H NMR (CDCI3) δ 0.89 (t, 3H, J = 6.6, CH3CH2), 1.23-1.43 (m, 4H, 2 x CH2), 1.56-1.75 (m, 2H, CH2CH2N), 2.03, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.42-3.76 (m, 2H, CH2N), 4.22-4.44 (m, 2H, H-4', 1 x H-51 4.57 (ABX, 1 H, J = 4.4, J = 11.7, 1 x H-5% 5.34 (t, 1 H, J = 5.1 , CH2NH), 5.46 (dd, 1 H, J = 3.7, J = 5.9, H-3), 5.74 (dd, 1 H, J = 5.9, J = 6.6, H-21), 6.13 (d, 1 H, J = 6.6, H-11), 8.07 (s, 1 H, H-2), 11.47 (br s, 1 H, NH). 13C NMR (CDCI3) δ 13.4, 19.8, 20.1 , 20.2, 21.8, 28.6, 28.8, 42.8, 62.5, 69.4, 70.5, 79.9, 84.5, 134.4, 142.0, 143.8, 152.7, 168.5, 169.1 , 169.2, 169.8.

2I,3",5I-Tri-O-acetyI-8-(/7-hexylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 58%. Yellow oil. 1H NMR (CDCI3) δ 0.89 (t, 3H, J = 6.6, 1 * CH3CH2), 1.25-1.44 (m, 6H, 3 * CH2), 1.55-1.77 (m, 2H, CH2CH2NH), 2.04, 2.12, 2.15 (3 x s, 3 x 3H, 3 x CH3 CO), 3.44-3.77 (m, 2H, CH2N), 4.26-4.44 (m, 2H, H-4', 1 x H-51), 4.58 (dd, 1 H, J = 4.4, J = 11.7, 1 x H-51 5.29 (t, 1 H1 J = 5.1 , NH), 5.45 (dd, 1 H, J = 4.4, J = 6.6, H-31), 5.73 (t, 1 H, J = 6.6, H-21), 6.13 (d, 1 H, J = 6.6, H-1% 8.02 (s, 1 H, H-2), 11.68 (br s, 1 H, NH). 13C NMR (CDCI3) δ 13.7, 20.1 , 20.3, 20.4, 22.2, 26.2, 29.2, 31.2, 43.1 , 62.7, 69.6, 70.6, 80.3, 84.7, 134.5, 142.0, 144.1 , 152.9, 168.8, 169.2, 169.4, 169.9.

Z'.SSδ'-Tri-O-acetyl-δ-^Z-methyl-butyO-aminol-thioinosine This compound was prepared according to general procedure B. Yield: 44 %. Yellow oil. 1H NMR (CDCI3) δ 0.87-1.00 (m, 6H, 2 x CH3), 1.07-1.31 (m, 1 H, CH3CHH), 1.37-1.60 (m, 1 H, CH3CHH), 1.64-1.92 (m, 1H, CH3CH), 2.04, 2.10, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.27-3.70 (m, 2H, CH2N), 4.26-4.45 (m, 2H, H-4', 1 x H-51), 4.55 (dd, 1 H, J = 3.7, J = 12.1 , 1 x H-51 5.30 (t, 1 H, J = 5.5, NH), 5.46 (dd, 1H, J = 4.4, J = 6.2, H-31), 5.77 (t, 1 H, J = 6.2, H-2% 6.11 (d, 1 H, J = 6.2, H-11), 8.01 (s, 1 H, H-2), 11.76 (br s, 1 H, NH). 13C NMR (CDCI3) δ 10.9, 16.8, 20.1 , 20.3, 20.5, 26.6, 26.8, 34.2, 48.8, 62.8, 69.7, 70.7, 80.3, 84.8, 134.6, 142.0, 144.2, 153.1 , 168.8, 169.3, 169.5, 170.0.

21,3',5l-Tri-0-acetyl-8-(cyclopropylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 49%. Yellow oil. 1H NMR (CDCI3) δ 0.58-0.70 (m, 2H1 2 * CHH), 0.81-0.94 (m, 2H, CH2CH2NH), 2.05, 2.14, 2.16 (3 x s, 3 x 3H, 3 x CH3 CO), 2.98-3.13 (m, 1H, CHN), 4.26-4.41 (m, 2H, H-4', 1 x H-51), 4.46-4.60 (m, 1H, 1 x H-5"), 5.46 (dd, 1 H, J = 4.4, J = 5.9, H-31), 5.65-5.77 (m, 2H, H-2', CHNH), 6.13 (d, 1H, J = 5.8, H-11), 8.17 (s, 1H, H-2), 11.75 (br s, 1 H, NH). 13C NMR (CDCI3) δ 7.3, 20.1 , 20.3, 20.5, 24.8, 62.6, 69.6, 70.8, 80.0, 84.9, 134.2, 143.1 , 143.9, 153.4, 169.3, 169.5, 169.6, 170.1.

2',3',5'-Tri-O-acetyl-8-(cyclopentylamino)-thioinosine This compound was prepared according to general procedure B. Yield: 22%. Brownish oil. 1H NMR (CDCI3) δ 1.41-1.70 (m, 8H, 4 x CH2), 2.05, 2.06, 2.15 (3 x s, 3 x 3H, 3 x CH3 CO), 4.29-4.63 (m, 4H, H-4', H-5', CHNH), 5.15 (d, 1 H J = 5.6, CHNH), 5.49 (t, 1 H, J = 5.9, H-3% 5.81 (t, 1 H, J = 5.9, H-21), 6.04 (d, 1 H, J = 5.9, H-11), 8.01 (s, 1 H1 H-2), 11.77 (br s, 1 H, NH). 13C NMR (CDCI3) δ 20.1 , 20.3, 20.4, 23.3, 32.8, 32.9, 54.5, 62.7, 69.6, 71.0, 80.1 , 85.0, 134.6, 142.0, 144.0, 152.7, 168.9, 169.4, 170.1.

Z'^'jS'-Tri-O-acetyl-δ-tcyclohexylaminoJ-thioinosine This compound was prepared according to general procedure B. Yield: 41 %. Yellow solid. 1H NMR (CDCI3) δ 1.05-1.85 (m, 8H, 2 x NHCHCHH, 3 x CH2), 2.05, 2.11 , 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 1.98-2.24 (m, 2H, 2 x NHCHCHH), 4.02- 4.23 (m, 1 H, CH2CHNH), 4.28-4.58 (m, 3H, H-41, H-51), 5.07 (d, 1 H, J = 8.0, CH2CHNH), 5.48 (dd, 1 H, J = 4.4, J = 5.9, H-31), 5.81 (dd, 1 H, J = 5.9, J = 6.6, H-21), 6.05 (d, 1 H, J = 6.6, H-11), 7.99 (s, 1 H, H-2), 11.79 (br s, 1 H, NH). 13C NMR (CDCI3) δ 20.1 , 20.3, 20.6, 24.6, 25.3, 33.0, 33.3, 51.3, 62.7, 69.6, 70.9, 80.2, 84.9, 134.7, 141.9, 144.0, 152.3, 168.7, 169.3, 169.4, 170.1.

2\3',5I-Tri-O-acetyl-8-pyrrolidino-thioinosine This compound was prepared according to general procedure B. Yield: 55%. Brownish oil. 1H NMR (CDCI3) δ 1.78-2.09 (m, 4H, 2 x CH2CH2N), 2.03, 2.05, 2.11 (3 x s, 3 x 3H, 3 x CH3CO), 3.60-3.82 (m, 4H, 2 x CH2N), 4.21-4.53 (m, 3H, H-4', H-51), 5.80 (t, 1 H, J = 5.1 , H-31 5.98 (d, 1 H, J = 5.1 , H-11), 6.40 (t, 1 H, J = 5.1 , H-21), 8.05 (s, 1 H, H-2), 11.74 (br s, 1 H, NH). 13C NMR (CDCI3) δ 20.0, 20.1 , 20.2, 25.3, 50.7, 62.5, 70.0, 70.9, 79.3, 86.3, 134.8, 141.9, 143.6, 155.3, 168.8, 169.0, 170.1 , 170.7.

2I,3*,5l-Tri-O-acetyl-8-piperidino-thioinosine This compound was prepared according to general procedure B. Yield: 82 %. Brown oil. 1H NMR (CDCI3) δ 1.56-1.83 (m, 6H, (CH2)3CH2N), 2.05, 2.08, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 3.22-3.49 (m, 4H, 2 x CH2N), 4.26-4.55 (m, 3H, H-4', H-51), 5.79-5.88 (m, 2H, H-V, H-3), 6.25 (t, 1 H, J = 5.5, H-2\ 8.10 (s, 1 H, H-2), 12.05 (br s, 1 H, NH). 13C NMR (CDCI3) δ 19.9, 20.0, 20.2, 23.3, 24.9, 51.5, 62.4, 69.9, 71.1 , 79.2, 86.4, 134.0, 143.3, 143.5, 157.0, 168.7, 169.0, 170.1 , 170.6.

21,3',5l-Tri-O-acetyl-8-tø-morpholino-thioinosine This compound was prepared according to general procedure B. Yield: 84 %. Yellow oil. 1H NMR (CDCI3) δ 2.07, 2.09, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.27-3.42 (m, 2H, 2 x CHHN), 3.44-3.59 (m, 2H, 2 x CHHN), 3.78-3.99 (m, 4H, 2 x CH2N), 4.25-4.51 (m, 3H, H-4', H-5% 5.81-5.90 (m, 2H, H-V, H-3\ 6.30 (dd, 1 H, J = 4.8, J = 5.9, H-21), 8.10 (s, 1 H, H-2), 12.15 (br s, 1 H, NH). 13C NMR (CDCI3) δ 20.1 , 20.2, 20.5, 50.7, 62.5, 65.8, 69.9, 71.1 , 79.3, 86.3, 133.9, 143.4, 144.5, 155.9, 168.8, 169.1 , 170.1 , 170.7. σ'^'.S'-Tri-O-acetyl-e-benzyl-δ-methylamino-thioinosine This compound was prepared according to general procedure C. Yield: 61 %. White solid. 1H NMR (CDCI3) δ 2.01 , 2.13, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.13 (d, 2H1 J = 5.1 , CH3N), 4.61 (m, 2H, H-4', 1 x H-51), 4.61 (ABX, 1 H, J = 3.7, J = 11.7, 1 x H-51), 4.62 (s, 2H, CH2S), 5.36 (t, 1H, J = 5.1 , NH), 5.47 (dd, 1 H, J = 3.4, J = 6.2, H-31), 5.73 (dd, 1 H, J = 6.2, J = 6.9, H-T), 6.24 (d, 1H, J = 6.9, H-11), 7.21-7.34 (m, 3H, CH arom), 7.43-7.49 (m, 2H1 CH arom), 8.52 (s, 1 H, H-2). 13C NMR (CDCI3) δ 18.8, 18.9, 19.0, 31.1 , 34.8, 61.6, 68.9, 69.9, 78.3, 83.9, 125.7, 127.0, 127.7, 130.1 , 137.0, 146.9, 148.3, 149.9, 153.1 , 167.9, 168.1 , 168.8.

2',3',5'-Tri-O-acetyl-6-benzyl-8-ethylamino-thioinosine This compound was prepared according to general procedure C. Yield: 52 %. White solid. 1H NMR (CDCI3) δ 1.30 (t, 3H, J = 7.3, CH3CH2), 2.03, 2.09, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.46-3.69 (m, 2H, CH2N), 4.24-4.58 (m, 3H, H-4', H-51), 4.62 (s, 2H, CH2S), 5.24 (t, 1 H, J = 5.5, NH), 5.51 (dd, 1 H, J = 3.7, J = 5.9, H-31), 5.84 (t, 1 H, J = 6.2, H-21), 6.17 (d, 1 H, J = 6.6, H-I1), 7.22-7.36 (m, 3H, CH arom), 7.38-7.47 (m, 2H, CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 14.8, 20.2, 20.4, 20.5, 32.7, 37.9, 62.9, 70.0, 70.6, 80.5, 84.5, 126.9, 128.3, 129.0, 130.6, 137.7, 148.6, 149.2, 152.5, 152.9, 169.4, 169.5, 170.1.

2tJ3',5"-Tri-O-acetyl-6-benzyl-8-(/i-propylamino)-thioinosin e This compound was prepared according to general procedure C. Yield: 59 %. Yellowish solid. 1H NMR (CDCI3) δ 0.97 (t, 3H, J = 7.3, CH3CH2), 2.03, 2.07, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.36-3.66 (m, 2H, CH2N), 4.25-4.42 (m, 1 H, H-4', 1 x H-51), 4.56 (ABX, 1 H, J = 3.7, J = 11.7, 1 x H-51), 4.62 (s, 2H, CH2S), 5.30 (t, 1 H, J = 5.9, NH), 5.52 (dd, 1 H, J = 4.0, J = 5.9, H-31), 5.87 (t, 1 H, J = 6.2, H-21), 6.16 (d, 1 H, J = 6.2, H-1), 7.17-7.34 (m, 3H, CH arom), 7.38-7.49 (m, 2H, CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 11.0, 19.9, 20.1 , 20.2, 22.2, 32.5, 44.5, 62.7, 69.8, 70.6, 80.0, 84.4, 126.7, 128.0, 129.1 , 130.5, 137.5, 148.3, 149.0, 152.0, 152.9, 169.1 , 169.2, 169.8.

21,3">51-Tri-O-acetyl-6-benzyl-8-(n-butylamino)-thioin osine This compound was prepared according to general procedure C. Yield: 66 %. Off-white solid. 1H NMR (CDCI3) δ 0.95 (t, 3H, J = 7.3, CH3CH2), 1.30-1.50 (m, 2H, CH2CH3), 1.55-1.75 (m, 2H, CH2CH2N), 2.03, 2.07, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.39-3.69 (m, 2H, CH2N), 4.27-4.43 (m, 2H, H-4\ 1 x H-5% 4.56 (ABX, 1H, J = 3.7, J = 11.7, 1 x H-51), 4.62 (s, 2H, CH2S), 5.25 (t, 1 H, J = 5.4, NH), 5.53 (dd, 1 H, J = 4.4, J ~ 5.9, H-31), 5.87 (t, 1 H, J = 5.9, H-21), 6.15 (d, 1 H, J = 5.9, H-f 1), 7.17-7.34 (m, 3H, CH arom), 7.41-7.49 (m, 2H, CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 13.6, 19.8, 20.1 , 20.4, 31.4, 32.7, 42.8, 62.9, 69.9, 70.8, 80.3, 84.6, 126.9, 128.2, 128.9, 130.6, 137.7, 148.5, 149.2, 152.3, 153.0, 169.4, 169.5, 170.0.

2'J3",5I-Tri-0-acetyl-6-benzyl-8-(n-pentylamino)-thioinos ine This compound was prepared according to general procedure C. Yield: 95 %. Yellowish oil. 1H NMR (CDCI3) δ 0.85-0.94 (m, 3H, CH3CH2), 1.23-1.45 (m, 4H, 2 x CH2), 1.60-1.73 (m, 2H, CH2CH2N), 2.05, 2.07, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 3.38-3.67 (m, 2H, CH2N), 4.27-4.41 (m, 2H, H-4\ 1 x H-51), 4.58 (dd, 1 H, J = 4.4, J = 11.7, 1 x H-51), 4.62 (s, 2H, CH2S), 5.03 (t, 1 H, J = 5.1 , CH2NH), 5.53 (dd, 1 H, J = 3.7, J = 5.9, H-31), 5.87 (t, 1 H, J = 5.9, H-2% 6.16 (d, 1 H, J = 5.9, H-11), 7.18-7.33 (m, 3H, CH arom), 7.45 (dd, 2H, J = 1.5, J = 8.0, CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 13.5, 19.8, 20.0, 20.1 , 21.9, 28.5, 28.6, 32.4, 42.7, 62.6, 69.7, 70.6, 79.9, 84.4, 126.6, 127.9, 128.6, 130.5, 137.5, 148.1 , 149.0, 151.8, 152.8, 169.0, 169.1 , 169.7.

2',3',5'l-Tri-O-acetyl-6-benzyl-8-(n-hexylamino)-thioinosine This compound was prepared according to general procedure C. Yield: 86 %. White solid. 1H NMR (CDCI3) δ 0.88 (t, 3H, J = 6.6, CH3CH2), 1.25-1.45 (m, 4H, CH2CH3), 1.53-1.77 (m, 4H, CH2CH2N), 2.03, 2.07, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.37-3.69 (m, 2H, CH2N), 4.27-4.42 (m, 2H, H-4', 1 x H-51), 4.56 (ABX, 2H, J = 3.7, J = 11.7, 1 x H-5% 4.62 (s, 2H, CH2S), 5.25 (t, 1H, J = 5.4, NH), 5.53 (dd, 1H, J = 3.7, J = 5.9, H-3% 5.85 (t, 1H, J = 5.9, H-2\ 6.15 (d, 1 H, J = 5.9, H-11), IM-I, .37 (m, 3H, CH arom), 7.45 (dd, 2H, J = 1.5, J = 8.0 CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 13.9, 20.1 , 20.3, 20.8, 22.3, 26.3, 29.2, 31.2, 32.7, 43.0, 62.9, 69.9, 70.8, 80.3, 84.6, 126.9, 128.2, 128.9, 130.6, 137.7, 148.5, 149.2, 152.3, 153.0, 169.3, 169.4, 170.0.

2I,3',5'-Tri-0-acetyl-6-benzyl-8-[(2-methyl-butyl)-amino] -thioinosine This compound was prepared according to general procedure C. Yield: 64 %. Yellow oil. 1H NMR (CDCI3) δ 0.87-0.99 (m, 6H, 2 x CH3), 1.07-1.31 (m, 1 H, CH3CHH), 1.36-1.58 (m, 1 H, CH3CHH), 1.64-1.86 (m, 1 H, CH3CH), 2.04, 2.05, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 3.18-3.33 (m, 0.5H, CHHNH), 3.36-3.46 (m, 1H, CHHNH), 3.49-3.65 (m, 0.5H, CHHNH), 4.25-4.43 (m, 2H, H-4\ 1 x H-51), 4.48-4.59 (m, 1H, 1 x H-5), 4.62 (s, 2H, CH2S), 5.28 (m, 1 H, NH), 5.49-5.58 (m, 1 H1 H-3% 5.86-5.95 (m, 1 H, H-2), 6.12-6.18 (m, 1 H, H-1), 7.16-7.34 (m, 3H, CH arom), 7.41-7.49 (m, 2H, CH arom), 8.49 (s, 1 H, H-2). 13C NMR (CDCI3) δ 11.1 , 17.0, 20.2, 20.5, 26.8, 26.9, 32.8, 34.5, 48.8, 63.0, 70.0, 71.0, 80.4, 84.7, 127.0, 128.3, 129.0, 130.7, 137.8, 148.6, 149.2, 152.5, 153.2, 169.4, 169.5, 170.0.

2',3',5'-Tri-0-acetyl-6-benzyl-8-(cyclopropylamino)-thioinos ine This compound was prepared according to general procedure C. Yield: 64 %. White solid. 1H NMR (CDCI3) δ 0.59-0.69 (m, 2H, CH2), 0.82-0.93 (m, 2H, CH2), 2.02, 2.12, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 2.88-3.01 (m, 2H, CH2N), 4.27-4.39 (m, 2H, H-4', 1 x H-51), 4.46-4.58 (m, 1 H, 1 x H-51), 4.64 (s, 2H, CH2S), 5.47-5.56 (m, 1H, H-31), 5.57 (d, 1H, J = 1.5, NH), 5.78 (t, 1H, J = 6.2, H-21), 6.14 (d, 1H, J = 6.2, H-1% 7.17-7.35 (m, 3H, CH arom), 7.41-7.50 (m, 2H, CH arom), 8.51 (s, 1 H, H-2). 13C NMR (CDCI3) δ 7.0, 7.2, 20.1 , 20.3, 20.4, 24.8, 32.7, 62.7, 69.8, 70.9, 80.1 , 84.6, 126.9, 128.2, 128.9, 130.5, 137.6, 148.7, 149.0, 153.0, 153.3, 169.3, 169.4, 170.0.

21,3',5'-Tri-0-acetyl-6-benzyl-8-(cyclopentylamino)-thioi nosine This compound was prepared according to general procedure C. Yield: 63 %. Colourless oil. 1H NMR (CDCI3) δ 1.41-1.80 (m, 6H, NHCHCHH, 2 x CH2), 2.03, 2.05, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 2.08-2.12 (m, 2H, NHCHCHH), 4.27-4.56 (m, 4H, H-4', H-5', CHNH ), 4.62 (s, 2H, CH2S), 5.08 (d, J = 6.8, 1 H, NH), 5.57 (dd, 1 H, J = 4.8, J = 5.7, H-31), 5.97 (t, 1H, J = 5.7, H-2% 6.05 (d, 1 H, J = 5.7, H-11), 7.21-7.34 (m, 3H, CH arom), 7.45 (dd, 2H, J = 1.8, J = 8.1 , CH arom), 8.49 (s, 1 H, H-2). 13C NMR (CDCI3) δ 20.3, 20.4, 20.5, 23.5, 32.8, 33.0, 33.1 , 54.6, 62.8, 70.0, 71.3, 80.2, 85.0, 126.9, 128.3, 129.0, 130.8, 137.7, 148.5, 149.0, 152.5, 152.7, 169.5, 169.6, 170.2.

2l,3',5'-Tri-O-acetyl-6-benzyl-8-(cyclohexylamino)-thioin osine This compound was prepared according to general procedure C. Yield: 59 %. Colourless oil. 1H NMR (CDCI3) δ 1.12-1.84 (m, 8H, 2 x NHCHCHH, 3 x CH2), 2.04, 2.05, 2.15 (3 x s, 3 x 3H, 3 x CH3CO), 2.01-2.12 (m, 2H, 2 x NHCHCHH), 3.81-4.03 (m, 1 H, CH2CHNH), 4.29-4.57 (m, 3H, H-4\ H-51), 4.62 (s, 2H, CH2S), 5.01 (d, J = 7.7, 1 H, NH), 5.57 (dd, 1 H, J = 4.8, J = 5.5, H-31), 5.97 (t, 1 H, J = 5.5, H-21), 6.07 (d, 1 H, J = 5.5, H-11), 7.18-7.33 (m, 3H, CH arom), 7.45 (dd, 2H, J = 1.8, J = 8.0, CH arom), 8.48 (s, 1 H, H-2). 13C NMR (CDCI3) δ 20.3, 20.4, 20.6, 24.7, 25.5, 32.7, 32.9, 33.2, 51.5, 62.9, 70.0, 71.3, 80.2, 85.0, 126.9, 128.3, 129.0, 130.8, 137.7, 148.4, 149.0, 152.3, 169.5, 170.1.

2',3",5'-Tri-O-acetyl-6-benzyl-8-pyrrolidino-thioinosine This compound was prepared according to general procedure C. Yield: 42 %. Colourless oil. 1H NMR (CDCI3) δ 1.90-2.09 (m, 4H, 2 x CH2N), 2.05, 2.06, 2.13 (3 x s, 3 x 3H, 3 x CH3CO), 3.62-3.78 (m, 4H, 2 x CH2N), 4.26-4.37 (m, 1 H, H-4', 1 x H-51), 4.45-4.57 (m, 1H, 1 x H-51), 4.61 (s, 2H, CH2S), 5.95-6.03 (m, 2H1 H- 1', H-31), 6.59 (dd, 1 H, J = 4.8, J = 5.8, H-2% 7.20-7.33 (m, 3H, CH arom), 7.40-7.48 (m, 2H, CH arom), 8.51 (s, 1 H, H-2). 13C NMR (CDCI3) δ 20.3, 20.4, 20.5, 25.6, 32.6, 50.8, 62.8, 70.5, 71.3, 79.6, 86.8, 126.9, 128.2, 129.0, 131.0, 137.7, 148.7, 149.4, 152.9, 155.7, 169.1 , 169.3, 170.4.

2',3",5"-Tri-O-acetyl-6-benzyl-8-piperidino-thioinosine This compound was prepared according to general procedure C. Yield: 48 %. Colourless oil. 1H NMR (CDCI3) δ 1.57-1.84 (m, 6H, 3 x CH2), 2.06, 2.07, 2.13 (3 x s, 3 x 3H, 3 x CH3CO), 3.19-3.45 (m, 4H, 2 x CH2N), 4.29-4.41 (m, 2H, H-4', 1 x H-51), 4.52 (ABX, 1H, J = 6.2, J = 13.9, 1 x H-51), 4.62 (s, 2H, CH2S), 5.84 (d, 1H, J = 4.8, H-11), 6.00 (t, 1H, J = 5.9, H-31), 6.38 (dd, 1 H, J = 4.8, J = 5.9, H-21), 7.17-7.34 (m, 3H, CH arom), 7.44 (dd, 2H, J = 1.8, J = 8.0, CH arom), 8.58 (s, 1 H, H-2). 13C NMR (CDCI3) δ 20.3, 20.4, 20.5, 23.8, 25.2, 32.5, 51.8, 62.8, 70.4, 71.4, 79.5, 86.9, 126.9, 128.2, 128.9, 131.1 , 137.5, 149.0, 149.9, 155.5, 157.4, 168.9, 169.2, 170.3.

2',3',5'-Tri-O-acetyl-6-benzyl-8-morpholino-thioinosine This compound was prepared according to general procedure C. Yield: 66 %. Colourless oil. 1H NMR (CDCI3) δ 2.06, 2.07, 2.14 (3 x s, 3 x 3H, 3 x CH3CO), 3.24- 3.29 (m, 2H, 2 x CHHN), 3.42-3.57 (m, 2H, 2 x CHHN), 3.77-3.97 (m, 4H, 2 x CH2O), 4.27-4.39 (m, 2H, H-4', 1 x H-5% 4.43-5.56 (m, 1 H, 1 x H-5), 4.62 (s, 2H, CH2S), 5.86 (d, 1 H, J = 4.6, H-11), 6.01 (t, 1 H, J = 5.7, H-31), 6.44 (dd, 1 H, J = 4.6, J = 5.7, H-2% 7.17-7.34 (m, 3H, CH arom), 7.45 (dd, 2H, J = 1.8, J = 8.0, CH arom), 8.61 (s, 1H, H-2). 13C NMR (CDCI3) δ 20.1 , 20.3, 20.4, 32.5, 50.9, 62.6, 65.8, 70.3, 71.3, 79.6, 86.6, 126.9, 128.2, 128.8, 129.7, 137.3, 148.8, 150.1 , 156.3, 168.9, 169.2, 170.2.

Example 1 : 6-Benzyl-8-methylamino-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri-O-acetyl-6- behzyl-8-methylamino-thioinosine. Yield: 83 %. White solid. M. p.: 193°C (dec). 1H NMR (MeOD) δ 3.02 (s, 3H, CH3), 3.76-3.89 (m, 2H, H-5% 4.15 (dd, 1 H, J = 1.8, J = 4.0, H-41), 4.27 (dd, 1 H, J = 1.8, J = 5.5, H-31), 4.61 (s, 2H, CH2S), 4.70 (dd, 1 H, J = 5.5, J = 7.7, H-21), 6.61 (d, 1 H, J = 7.7, H-f)> 7.17-7.33 (m, 3H, CH arom), 7.42 (dd, 2H, J = 2.2, J = 8.0, CH arom), 8.39 (s, 1 H, H-2). 13C NMR (CDCI3/MeOD 1/2) δ 29.2, 33.6, 62.6, 72.3, 72.6, 87.1 , 88.3, 127.8, 129.1 , 129.7, 131.7, 138.7, 148.7, 150.5, 152.1 , 155.4. HRMS (ESI) m/z Found: 404.1408 [M + H]+, Calcd: 404.1392. (C18H21N5O4S ■ 0.15 CH2CI2) C1H1N1S.

Example 2: 6-Benzyl-8-ethylamino-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri-O-acetyl-6- benzyl-8-ethylamino-thioinosine. Yield: 96 %. White solid. M. p.: 102-104°C. 1H NMR (CDCI3/MeOD 1/1 , v/v) δ 1.21 (t, 3H, J = 7.3, CH3CH2), 3.34-3.56 (m, 2H, CH2N), 3.77 (ABX, 1 H, J = 1.1 , J = 12.4, 1 x H-5% 3.92 (ABX, 1 H, J = 2.0, J = 12.4, 1 x H-51), 4.18-4.24 (m, 1 H, H-41), 4.30 (dd, 1 H, J = 1.6, J = 5.5, H-31), 4.61 (s, 2H, CH2S), 4.70 (dd, 1 H, J = 5.5, J = 7.1 , H-21), 5.90 (d, 1 H, J = 7.1 , H-11), 7.18-7.34 (m, 3H, CH arom), 7.40-7.48 (m, 2H, CH arom), 8.39 (s, 1H, H-2). 13C NMR (CDCI3/MeOD 1/1 , v/v) δ 14.6, 33.5, 38.1 , 62.4, 72.0, 72.3, 86.8, 87.9, 127.6, 128.9, 129.5, 131.7, 138.4, 148.3, 150.1 , 151.9, 154.3. HRMS (ESI) m/z Found: 418.1510 [M + H]+, Calcd: 418.1549. (C19H23N5O4S ■ 0.05 CH2CI2) C,H,N,S.

Example 3: 6-Benzyl-8-(n-propylamino)-thioinosine This compound was prepared according to general procedure D from 2',3I,5'-Tri-O-acetyl-6- benzyl-8-(/7-propylamino)-thioinosine. Yield: 78%. White solid. M. p.: 108°C. 1H NMR (MeOD) δ 0.97 (t, 3H, J = 7.3, CH3CH2), 1.56-1.77 (m, 2H, CH3CH2), 3.34-3.50 (m, 2H, CH2N), 3.74-3.86 (m, 2H, H-51), 4.10-4.17 (m, 1H, H-41), 4.21-4.29 (m, 1 H, H-3), 4.61 (s, 2H, CH2S), 4.69 (dd, 1 H, J = 5.5, J = 7.7, H-2% 6.13 (d, 1 H, J = 7.7, H-1% 7.13-7.31 (m, 3H, CH arom), 7.36-7.45 (m, 2H, CH arom), 8.37 (s, 1 H, H-2). 13C NMR (MeOD) δ 11.8, 23.4, 33.8, 45.4, 62.9, 72.6, 72.8, 87.5, 88.4, 128.1 , 129.4, 130.0, 132.0, 139.4, 149.1 , 151.1 , 152.1 , 155.1. HRMS (ESI) m/z Found: 432.1746 [M + H]+, Calcd: 432.1705. (C20H25N5O4S) C1H1N1S.

Example 4: 6-Benzyl-8-(n-butylamino)-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri-O-acetyl-6- benzyl-8-(n-butylamino)-thioinosine. Yield: 87 %. White solid. M. p.: 860C. 1H NMR (MeOD) δ 0.95 (t, 3H, J = 7.3, CH3CH2), 1.31-1.51 (m, 2H, CH3CH2), 1.55-1.73 (m, 2H, CH2CH2N), 3.34-3.58 (m, 2H, CH2N)1 3.77- 3.83 (m, 2H, H-5), 4.11-4.16 (m, 1 H, H-41), 4.26 (dd, 1H, J = 1.8, J = 5.5, H-31), 4.61 (s, 2H, CH2S), 4.68 (dd, 1 H, J = 5.5, J = 7.7, H-21), 6.14 (d, 1 H, J = 7.7, H-11), 7.15-7.31 (m, 3H, CH arom), 7.37-7.46 (m, 2H, CH arom), 8.37 (s, 1 H, H-2). 13C NMR (MeOD) δ 14.2, 21.1 , 32.2, 33.8, 43.4, 62.9, 72.6, 72.7, 87.5, 88.3, 128.0, 129.4, 130.0, 132.0, 139.3, 149.0, 151.0, 152.0, 155.0. HRMS (ESI) m/z Found: 446.1818. [M + H]+, Calcd: 446.1862. (C21H27N5O4S) C1H1N1S.

Example 5: 6-Benzyl-8-(n-pentylamino)-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri-O-acetyl-6- benzyl-8-(n-pentylamino)-thioinosine. Yield: 83 %. White foam. M. p.: 80- 82°C. 1H NMR (MeOD) δ 0.89 (t, 3H, J = 6.9, CH3CH2), 1.28-1.43 (m, 4H, 2 x CH2), 1.61-1.76 (m, 2H, CH2CH2N), 3.32-3.60 (m, 2H, CH2N), 3.74-3.87 (m, 2H, H-5% 4.12-4.18 (m, 1H, H-4\ 5.51 (dd, 1 H, J = 1.8, J = 5.5, H-3% 4.60 (s, 2H, CH2S), 4.69, (dd, 1 H, J = 5.5, J = 7.3, H-21), 6.14 (d, 1 H, J = 7.3, H-1% 7.12-7.31 (m, 3H, CH arom), 7.40 (dd, 2H, J = 1.5, J = 8.0, CH arom), 8.36 (s, 1 H, H-2). 13C NMR (MeOD) δ 14.4, 23.3, 29.7, 30.1 , 33.8, 43.7, 62.8, 72.7, 87.4, 91.1 , 128.0, 129.3, 129.9, 131.9, 139.1 , 148.9, 150.8, 152.0, 154.9. HRMS (ESI) m/z Found: 460.2022. [M + H]+, Calcd: 460.2018. Elem. anal. (C22H29N5O4S • 0.1 CH2CI2) C,H,N,S. Example 6: 6-Benzyl-8-(n-hexylamιno)-thioinosine This compound was prepared according to general procedure D from 2',3',51-Tri-O-acetyl-6- benzyl-8-(n-hexylamino)-thioinosine. Yield: 61 %. Colourless glass. M. p.: 780C. 1H NMR (MeOD) δ 0.88 (m, 3H, CH3CH2), 1.21-1.48 (m, 6H, 3 x CH2), 1.57-1.74 (m, 2H, CH2CH2N), 3.33-3.56 (m, 2H, CH2N), 3.74-3.87 (m, 2H, H-51), 4.14 (d, 1 H, J = 1.8, J = 3.7, H-4% 4.27 (dd, 1 H, J = 1.8, J = 5.5, H-31), 4.60 (s, 2H1 CH2S), 4.68 (dd, 1H, J = 5.5, J = 7.7, H-21), 6.14 (d, 1 H, J = 7.7, H-11), 7.13-7.30 (m, 3H, CH arom), 7.36-7.44 (m, 2H, CH arom), 8.36 (s, 1 H, H-2). 13C NMR (MeOD) δ 14.4, 23.6, 27.7, 30.1 , 32.6, 33.8, 43.7, 62.9, 72.6, 72.7, 87.5, 88.4, 128.0, 129.4, 130.0, 132.0, 139.4, 149.0, 151.0, 152.1 , 155.0. HRMS (ESI) m/z Found: 474.2135 [M + H]+, Calcd: 474.2175. Elem. anal. (C23H3IN5O4S ■ 0.25 CH2CI2) C1H1N1S.

Example 7: 6-Benzyl-8-[(2-methyl-butyl)-amino]-thioinosine This compound was prepared according to general procedure D from 2",3',5'-Tn- O-acetyl-6-benzyl-8-[(2-methyl-butyl)-amino]-thioinosine. Yield: 87 %. White solid. M.p.: 129°C. 1H NMR (MeOD) δ 0.86-0.97 (m, 6H, 2 x CH3), 1.03- 1.29 (m, 1 H, CH3CHH), 1.39-1.63 (m, 1 H, CH3CHH), 1.69-1.89 (m, 1 H, CH3CH), 3.13-3.50 (m, 2H, CH2N), 3.73-3.82 (m, 2H, H-5% 4.11-4.17 (m, 1 H, H-41), 4.25 (dd, 1 H, J = 1.5, J = 5.5, H-31), 4.61 (s, 2H, CH2S), 4.67 (dd, 1 H, J = 5.5, J = 7.7, H-21), 6.15 (d, 1 H, J = 7.7, H-1% 7.13-7.30 (m, 3H, CH arom), 7.40 (dd, 2H, J = 1.8, J = 7.7, CH arom), 8.36 (s, 1 H, H-2). 13C NMR (MeOD) δ 11.5, 17.4, 27.9, 28.0, 33.9, 35.4, 62.9, 72.7, 72.8, 87.6, 88.3, 128.1 , 129.4, 130.0, 132.1 , 139.4, 149.0, 151.2, 152.0, 155.2. HRMS (ESI) m/z Found: 460.2013 [M + H]+, Calcd: 460.2018. Elem. anal. (C22H29N5O4S ■ 0.05 CH2CI2) C1H1N1S.

Example 8: 6-Benzyl-8-(cyclopropylamino)-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tn- O-acetyl-e-benzyl-δ-fcyclopropylaminoy-thioinosine. Yield: 58 %. White solid. M.p.: 102°C. 1H NMR (MeOD) δ 0.56-0.66 (m, 2H, 2 x CHH), 0.76- 0.85 (m, 2H, 2 x CHH), 2.78-2.90 (m, 2H, CH2N), 3.72-3.88 (m, 2H1 H-5% 4.11 (dd, 1 H, J = 1.8, J = 3.7, H-4\ 4.23 (dd, 1 H, J = 1.8, J = 5.5, H-31), 4.61 (dd, 1 H, J = 5.5, J = 7.7, H-2\ 4.62 (s, 2H, CH2S), 6.14 (d, 1 H, J = 7.7, H-11), 7.15-7.32 (m, 3H, CH arom), 7.41-7.47 (m, 2H, CH arom), 8.41 (s, 1 H, H-2). 13C NMR (MeOD) δ 7.0, 7.6, 25.5, 33.8, 62.9, 72.5, 72.7, 87.5, 88.4, 128.1 , 129.4, 130.0, 131.7, 139.4, 149.3, 150.9, 152.8, 155.6. HRMS (ESI) m/z Found: 430.1497 [M + H]+, Calcd: 430.1549. Elem. anal. (C20H23N5O4S ■ 0.2 CH2CI2) C1H1N1S.

Example 9: 6-Benzyl-8-(cyclopentylamino)-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tn- O-acetyl-6-benzyl-8-(cyclopentylamino)-thioinosine. Yield: 80 %. White solid. M.p.: 175-176°C (dec). 1H NMR (MeOD) δ 1.50-1.84 (m, 6H, 2 x CH2, 2 x CHHCH), 1.94-2.13 (m, 2H, 2 x CHHCH), 3.76-3.85 (m, 2H, H-5% 4.12 (dd, 1 H, J = 1.8, J = 3.7, H-4\ 4.25 (dd, 1 H, J = 1.8, J = 5.5, H-3% 4.29-4.44 (m, 1 H, CHNH), 4.62 (s, 2H, CH2S)1 4.65 (dd, 1 H1 J = 5.5, J = 7.7, H-21), 6.15 (d, 1 H, J = 7.7, H-11), 7.15-7.32 (m, 3H, CH arom), 7.42 (dd, 2H, J = 1.8, J = 8.0, CH arom), 8.37 (s, 1 H, H-2). 13C NMR (CDCI3/MeOD 1/1) δ 24.6, 33.0, 33.1 , 33.6, 55.1 , 62.4, 72.0, 72.3, 86.9, 87.7, 127.7, 128.9, 130.0, 131.8, 138.4, 148.2, 150.2, 151.8, 154.1. HRMS (ESI) m/z Found: 458.1851 [M + H]+, Calcd: 458.1862. Elem. anal. (C22H27N5O4S ■ 0.05 CH2CI2) C,H,N,S.

Example 10: 6-Benzyl-8-(cyclohexylamino)-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri- O-acetyl-6-benzyl-8-(cyclohexylamino)-thioinosine. Yield: 93 %. White solid. M.p.: 108-109°C. 1H NMR (MeOD) δ 1.08-1.87 (m, 8H, 2 x NHCHCHH, 3 x CH2), 1.93-2.09 (m, 2H, 2 x NHCHCHH), 3.73-3.97 (m, 3H, H-5\ CH2CHNH), 4.11-4.17 (m, 1 H, H-4% 4.26 (dd, 1 H, J = 1.8, J = 5.8, H- 3), 4.61 (s, 2H, CH2S), 4.67 (dd, 1 H, J = 5.8, J = 7.7, H-2% 6.14 (d, 1 H, J = 7.7, H-1% 7.14-7.32 (m, 3H, CH arom), 7.38-7.44 (m, 2H, CH arom), 8.36 (s, 1 H, H-2). 13C NMR (CDCI3/MeOD 1/5, v/v) δ 26.3, 26.4, 26.5, 33.8, 33.9, 34.2, 53.2, 62.8, 72.5, 72.6, 87.4, 88.3, 128.0, 129.4, 130.0, 132.1 , 139.3, 148.9, 151.0, 151.9, 154.4. HRMS (ESI) m/z Found: 472.1994. [M + H]+, Calcd: 472.2018. Elem. anal. (C22H27N5O4S ■ 0.25 CH2CI2) C1H1N1S.

Example 11 : 6-Benzyl-8-pyrrolidino-thioinosine This compound was prepared according to general procedure D from 2',3\5I-Tri-O-acetyl-6- benzyl-8-pyrrolidino-thioinosine. Yield: 90 %. White solid. M. p.: 1580C (dec). 1H NMR (CDCI3/MeOD 1/9, v/v) δ 1.95-2.09 (m, 4H, 2 x CH2CH2N), 3.66-3.80 (m, 5H, 2 x CH2N, 1 x H-51), 3.88 (ABX, 1H, J = 2.6, J = 12.4, 1 x H-51), 4.14 (dd, 1 H, J = 2.6, J = 4.4, H-41), 4.38 (dd, 1 H, J = 1.8, J = 5.5, H- 31X 4.61 (s, 2H1 CH2S), 5.19 (dd, 1 H, J = 5.1 , J = 7.3, H-21), 6.05 (d, 1 H, J = 7.3, H-11), 7.21-7.32 (m, 3H, CH arom), 7.42 (dd, 2H, J = 1.5, J = 8.0, CH arom), 8.40 (s, 1 H, H-2). 13C NMR (CDCI.3/MeOD 2/1 , v/v) δ 26.1 , 33.3, 51.6, 63.6, 72.1 , 72.2, 87.2, 89.5, 127.5, 128.8, 129.4, 132.0, 138.0, 147.9, 149.3, 153.8, 156.3. HRMS (ESI) m/z Found: 444.1678 [M + H]+, Calcd: 444.1705. Elem. anal. (C2iH25N5O4S) C1H1N1S.

Example 12: 6-Benzyl-8-piperidino-thioinosine This compound was prepared according to general procedure D from 2',3',5'-Tri-O-acetyl-6- benzyl-8-piperidino-thioinosine. Yield: 86 %. Colourless glass. M. p.: 90- 92°C. 1H NMR (CDCI3/MeOD 1/9, v/v) δ 1.57-1.84 (m, 6H, 3 x CH2), 3.24- 3.50 (m, 4H, 2 x CH2N), 3.80 (ABX, 1 H, J = 2.9, J = 12.4, H-5% 4.08-4.15 (m, 1 H, H-41), 4.40 (dd, 1 H, J = 2.2, J = 5.5, H-31 4.61 (s, 2H, CH2S), 5.19 (dd, 1H, J = 5.5, J = 7.3, H-21), 5.81 (d, 1H, J = 7.3, H-1% 7.14-7.32 (m, 3H, CH arom), 7.37-7.46 (m, 2H, CH arom), 8.48 (s, 1 H, H-2). 13C NMR (CDCI3) δ 23.8, 25.1 , 32.9, 52.1 , 63.3, 72.1 , 86.5, 89.0, 127.1 , 128.3, 129.0, 130.2, 137.0, 147.9, 148.4, 156.4, 158.3. HRMS (ESI) m/z Found: 458.1834 [M + H]+, Calcd: 458.1862. Elem. anal. (C22H27N5O4S ■ 0.2 CH2CI2) C,H,N,S. Example 13: 6-Benzyl-8-morpholino-thioinosine This compound was prepared according to general procedure D from 2',3\51-Tri-O-acetyl-6- benzyl-8-morpholino-thioinosine. Yield: 94 %. Colourless glass. M. p.: 98- 99°C. 1H NMR (MeOD) δ 3.27-3.40 (m, 2H, CH2N), 3.45-3.58 (m, 2H, CH2N), 3.73 (ABX, 1 H, J = 2.9, J = 12.4, 1 x H-51), 3.81-3.94 (m, 5H, 2 x CH2O, 1 x H-51), 4.13 (dd, 1 H, J = 2.9, J = 4.5, H-4% 4.38 (dd, 1 H1 J = 2.2, J = 5.1 , H-31), 4.62 (s, 2H, CH2S), 5.17 (dd, 1H, J = 5.1 , J = 7.3, H-21), 5.87 (d, 1H, J = 7.3, H-11), 7.14-7.33 (m, 3H, CH arom), 7.42 (dd, 2H, J = 1.5, J = 8.0, CH arom), 8.52 (s, 1 H, H-2). 13C NMR (CDCI3) δ 33.0, 51.3, 63.3, 66.0, 72.2, 72.5, 86.6, 88.7, 127.2, 128.4, 129.0, 130.2, 136.9, 147.9, 148.6, 157.2, 157.6. HRMS (ESI) m/z Found: 460.1625 [M + H]+, Calcd: 460.1654. Elem. anal. (C2-IH25N5O4S ■ 0.2 CH2CI2) C1H1N1S.

9-Benzyl-6-(4-nitrobenzylsulfanyl)-purine This compound was prepared according to a literature procedure (T romp, R.A.; van Ameijde, S.; Pϋtz, C; Sundermann, C; Sundermann, B.; von Frijtag Drabbe Kϋnzel, J. K.; Uzerman, A.P. Submitted for publication)

9-Benzyl-6-chloropurine This compound was prepared according to a

literature procedure (Kanie, K.; Mizuno, K.; Kuroboshi, M.; Hiyama,

T. Bull. Chem. Soc. Jpn. 1998, 71, 1973-1991 ).

9-Benzyl-hypoxanthine This compound was prepared according to a literature procedure (Maruyama, T.; Kozai, S.; Uchida, M. Nucleosides & Nucleotides 1999, 18, 661-671 ).

9-Benzyl-8-bromo-hypoxanthine This compound was prepared according to a literature procedure.11 After work-up the product was washed with CH2CI2 and dried in vacuo to provide 62 as an off-white solid. Yield: 83 %. White solid. 1H NMR (DMSO-cfe) δ 5.37 (s, 2H, CH2N), 7.20- 7.42 (m, 5H, CH arom), 8.11 (s, 1 H, H-2), 12.53 (br s, 1 H, NH). 13C NMR (DMSO-dβ) δ 42.7, 124.3, 125.5, 127.2, 128.9, 135.6, 146.7, 150.0, 155.4.

9-Benzyl-8-(cyclopentylamine)-hypoxanthine This compound was prepared according to general procedure E. Yield: 67 %. White solid. 1H NMR (DMSO-de) δ 1.43-1.96 (m, 8H, 4 x CH2), 4.06-4.19 (m, 1H, CHN), 5.22 (s, 2H, PhCH2N), 6.46 (d, 1 H, J = 6.6, CHNH), 7.12-7.22 (m, 2H, CH arom), 7.24-7.38 (m, 3H, CH arom), 8.71 (s, 1 H, H-2), 12.01 (br s, 1 H, NH). 13C NMR (CDCI3) δ 23.1 , 33.0, 44.6, 54.3, 121.6, 126.8, 128.1 , 128.9, 134.8, 142.3, 149.0, 151.3, 158.0.

9-Benzyl-8-(cyclohexylamine)-hypoxanthine This compound was prepared according to general procedure E. Yield: 67%. Off-white solid. 1H NMR (CDCI3) δ 0.96-2.03 (m, 10H, 5 x CH2), 3.79-4.02 (m, 2H, CHNH, NHCH), 5.18 (s, 2H, CH2N), 7.18-7.43 (m, 5H, CH arom), 8.02 (s, 1 H, H-2), 11.54 (br s, 1 H, NH). 13C NMR (CDCI3) δ 24.1 , 24.8, 32.1 , 43.4, 50.7, 120.8, 126.2, 127.1 , 128.0, 134.8, 141.4, 148.0, 150.9, 155.8.

9-Benzyl-8-pyrrolidino-hypoxanthine This compound was prepared according to general procedure A with omittance of the acetylation step (Yield: 74 %) or general procedure E (Yield: 56 %). White solid. 1H NMR (CDCI3) δ 1.84-1.95 (m, 4H, 2 x CH2CH2N), 3.50-3.62 (m, 4H, 2 x CH2N), 5.41 (s, 2H, CH2N), 7.07-7.15 (m, 2H, CH arom), 7.25-7-.39 (m, 3H, CH arom), 7.92 (s, 1 H, H-2), 11.79 (br s, 1 H, NH). 13C NMR (CDCI3/MeOD 1/1 , v/v) δ 24.7, 45.7, 49.0, 121.1 , 125.1 , 127.0, 128.2, 136.0, 141.9, 149.1 , 152.8, 156.1.

9-Benzyl-8-morpholino-hypoxanthine This compound was prepared according to general procedure A with omittance of the acetylation step (Yield: 55 %) or general procedure E (Yield: 88 %). White solid. 1H NMR (CDCI3) δ 3.20 (t, 4H, J = 4.7, 2 x CH2N), 3.76 (t, 4H, J = 4.7, 2 x CH2O), 5.29 (s, 2H, CH2N), 7.15-7.41 (m, 5H, CH arom), 8.01 (s, 1 H, H-2), 11.72 (br s, 1 H, NH). 13C NMR (CDCI3/MeOD 4/1 , v/v) δ 46.3, 50.3, 66.1 , 121.4, 126.3, 127.8, 128.7, 135.4, 143.9, 149.4, 154.2, 157.4.

9-Benzyl-8-(cyclopentylamine)-6-mercaptopurine This compound was prepared according to general procedure B. Yield: 8%. White solid. 1H NMR (CDCIs/MeOD 3/1 , v/v) δ 1.29-1.69 (m, 6H, 2 x CHHCHNH, 2 x CH2), 4.32-4.52 (m, 1 H, CHNH), 5.24 (s, 2H, CH2N), 7.13-7.42 (m, 5H, CH arom), 7.98 (br s, 1 H1 H-2).

9-Benzyl-8-(cyclohexylamine)-6-mercaptopurine This compound was prepared according to general procedure B. Yield: 44%. Pink solid. 1H NMR (CDCI3/MeOD 1/1 , v/v) δ 1.03-2.04 (m, 10H, 5 x CH2), 3.83-4.05 (m, 1 H, NHCH), 5.27 (s, 2H, CH2N), 7.12-7.39 (m, 5H, CH arom), 8.02 (s, 1 H, H-2), 11.54 (br s, 1 H, NH). 13C NMR (CDCI3/MeOD 1/1 , v/v) δ 24.1 , 24.7, 32.2, 43.5, 50.6, 126.2, 127.3, 128.1 , 134.0, 134.3, 141.5, 144.4, 152.6, 167.0.

9-Benzyl-8-pyrrolidino-6-mercaptopurine This compound was prepared according to general procedure B. Yield: 53 %. White solid. 1H NMR (CDCIs/MeOD 5/1 , v/v) δ 1.81-2.02 (m, 4H, 2 x CH2CH2N), 3.55-3.72 (m, 4H, 2 x CH2N), 5.46 (s, 2H, CH2N), 7.02-7.14 (m, 2H, CH arom), 7.27- 7.40 (m, 3H, CH arom), 8.00 (s, 1 H, H-2). 13C NMR (CDCI3/MeOD 5/1 , v/v) δ 25.1 , 46.2, 49.6, 125.2, 127.5, 128.6, 134.2, 135.7, 141.7, 145.5, 154.3, 168.4.

9-Benzyl-8-morpholino-6-mercaptopurine This compound was prepared according to general procedure B. Yield: 54 %. Yellowish solid. 1H NMR (CDCI3/MeOD 3/2, v/v) δ 3.23-3.31 (m, 4H, 2 x CH2N), 3.71-3.79 (m, 4H, 2 x CH2O), 5.32 (s, 2H, CH2N), 7.14-7.22 (m, 2H, CH arom), 7.29-7.39 (m, 3H, CH arom), 8.02 (s, 1 H, H-2). 13C NMR (DMSO-d6) δ 46.0, 49.7, 65.5, 126.6, 127.6, 128.7, 133.0, 136.0, 144.2, 145.4, 155.3, 172.1. Example 14: 9-Benzyl-8-(cyclopentylamine)-6-(4-nitrobenzyl)-6- mercaptopurine This compound was prepared according to general procedure C from θ-Benzyl-δ-fcyclopentylamineJ-δ-mercaptopurine. Yield: 21%. Yellow solid. M.p.: 150-1510C. 1H NMR (CDCI3) δ 1.18-1.64 (m, 6H, 2 x CH2, 2 x CHHCHNH), 1.89-2.08 (m, 2H, 2 x CHHCHNH), 4.12 (d, 1 H, J = 7.3, CHNH), 4.25-4.42 (m, 1H, CHNH), 4.70 (s, 2H, CH2S), 5.19 (s, 2H, CH2N), 7.17 (dd, 2H, J = 1.8, J = 7.3, CH arom), 7.29-7.40 (m, 3H, CH arom), 7.64 (d, 2H, J = 8.8, CH arom), 8.12 (d, 2H, J = 8.8, CH arom), 8.51 (s, 1 H, H-2). 13C NMR (CDCI3) δ 23.2, 31.9, 33.2, 44.5, 54.4, 123.5, 127.0, 128.6, 129.3, 129.9, 131.0, 134.3, 146.6, 146.8, 148.7, 149.9, 150.3, 153.3. HRMS (ESI) m/z Found: 461.1736 [M + H]+, Calcd: 461.1754.

Example 15: 9-Benzyl-8-(cyclohexylamine)-6-(4-nitrobenzyl)-6- mercaptopurine This compound was prepared according to general procedure C from 9-Benzyl-8-(cyclohexylamine)-6-mercaptopurine. Yield: 19%. Yellow solid. M.p.: 66-68°C. 1H NMR (CDCI3) δ 0.96-1.64 (m, 8H, 3 x CH2, 2 x CHHCHNH), 1.83-1.97 (m, 2H, 2 x CHHCHNH), 3.82-4.01 (m, 1 H, NHCH), 4.08 (d, 1 H, J = 8.0, CHNH), 4.70 (s, 2H, CH2S), 5.20 (s, 2H, CH2N), 7.12-7.24 (m, 2H, CH arom), 7.28-7.42 (m, 3H, CH arom), 7.64 (d, 2H, J = 8.8, CH arom), 8.13 (d, 2H, J = 8.8, CH arom), 8.51 (s, 1 H, H-2). 13C NMR (CDCI3) δ 24.2, 25.3, 31.8, 32.9, 44.5, 50.9, 123.5, 126.9, 128.5, 129.2, 129.9, 134.3, 146.6, 146.8, 148.6, 149.7, 150.2, 153.0. HRMS (ESI) m/z Found: 475.1955 [M + H]+, Calcd: 475.1911. Elem. anal. (C25H26N6O2S • 0.3CH2CI2) C1H1N1S.

Example 16: 9-Benzyl-6-(4-nitrobenzyl)-8-pyrrolidino-6- mercaptopurine This compound was prepared according to general procedure C from 9-Benzyl-8-pyrrolidino-6-mercaptopurine. Yield: 83%. Yellow solid. M.p.: 1540C. 1H NMR (CDCI3) δ 1.85-1.93 (m, 4H, 2 x CH2CH2N), 3.56-3.63 (m, 4H, 2 x CH2CH2N), 4.71 (s, 2H, CH2S), 5.46 (s, 2H1 CH2N), 7.02-7.09 (m, 2H, CH arom), 7.24-7.37 (m, 3H, CH arom), 7.65 (d, 2H, J = 8.8, CH arom), 8.13 (d, 2H, J = 8.8, CH arom), 8.50 (s, 1 H, H-2). 13C NMR (CDCI3) δ 25.1 , 31.6, 46.1 , 49.2, 123.2, 125.2, 127.5, 128.6, 129.7, 130.5, 135.9, 146.3, 146.5, 148.2, 149.6, 151.1 , 154.6. HRMS (ESI) m/z Found: 447.1594 [M + H]+, Calcd: 447.1598. Elem. anal. (C23H22N6O2S • 0.2CH2CI2 ) C,H,N,S.

Example 17: 9-Benzyl-8-morpholino-6-(4-nitrobenzyl)-6- mercaptopurine This compound was prepared according to general procedure C from 9-Benzyl-8-morpholino-6-mercaptopurine. Yield: 78%. White solid. M.p.: 201 °C. 1H NMR (Bruker DMX 600 MHz, DMSO-d6, 60°C) δ 3.28 (t, 4H, J = 4.8, 2 x CH2N), 3.63 (t, 4H, J = 4.8, 2 x CH2O), 4.77 (s, 2H, CH2S), 5.38 (s, 2H, CH2N), 7.17-7.19 (m, 2H, CH arom), 7.26-7.34 (m, 3H, CH arom), 7.74(d, 2H, J = 8.8, CH arom), 8.15 (d, 2H, J = 8.8, CH arom), 8.57 (s, 1 H, H-2). 13C NMR (Bruker DMX 600 MHz, DMSO-de, 60°C) δ 30.7, 46.1 , 49.0, 65.2, 123.1 , 126.4, 127.3, 128.4, 129.2, 129.8, 135.7, 146.3, 146.5, 149.5, 150.8, 152.0, 156.2. HRMS (ESI) m/z Found: 463.1583 [M + H]+, Calcd: 463.1547. Elem. anal. (C23H22N6O3S ■ 0.1CH2CI2) C,H,N,S.

Example 18: 6-(Benzo[1 ,2,5]oxadiazol-5-ylmethylsulfanyl)-9-benzyl-8- pyrrolidin-1-yl-9H-purine This compound was prepared according to general procedure C from the respective thiol. Yield: 72 %. - Yellowish solid. - 1H NMR (CDCI3) δ = 1.84-1.97 (m, 4H, 2 x CH2CH2N), 3.54-3.67 (m, 4H, 2 x CH2N), 4.61 (s, 2H, CH2S), 5.47 (s, 2H, CH2N), 7.01-7.10 (m, 2H, CH arom), 7.23-7.37 (m, 3H, CH arom), 7.55 (dd, 1 H, J = 1.5, J = 9.1 , CH arom), 7.75 (d, 1 H, J = 9.1 , CH arom), 7.89 (s, 1 H, CH arom), 8.52 (s, 1 H, H-2). - 13C NMR (CDCI3) δ = 25.5, 32.4, 46.3, 49.6, 114.7, 116.2, 125.6, 127.7, 128.9, 134.1 , 136.4, 142.7, 148.7, 149.2, 151.7, 154.9, 158.8. Elem. anal. (C23H2iN7OS ■ 0.1 CH2CI2) C1H1N1S. Example 19: 6-(Benzo[1 ,2,5]oxadiazol-5-ylmethylsulfanyl)-9-benzyϊ-8- morpholin-4-yl-9H-purine This compound was prepared according to general procedure C from the respective thiol. Yield: 48 %. - White solid. - 1H NMR (CDCI3MeOD 9/1 , v/v) δ = 3.29 (t, 4H, J = 4.8, 2 x CH2), 3.73 (t, 4H, J = 4.8, 2 x CH2), 4.72 (s, 2H, CH2S), 5.32 (s, 2H, PhCH2N), 7.11-7.36 (m, 5H, CH Ph), 7.54 (dd, 1 H, J = 1.1 , J = 9.1 , CH Ph), 7.77 (d, 1 H, J = 9.1 , CH Ph), 7.91 (d, 1 H, J = 1.1 , CH Ph), 8.62 (s, 1 H, H-2). - 13C NMR (CDCI3/MeOD 2/1 , v/v) δ = 32.0, 46.5, 49.4, 65.7, 114.3, 115.8, 126.0, 127.6, 128.6, 133.8, 134.8, 142.2, 148.1 , 149.8. HRMS (ESI) m/z Found: 460.1536 [M + H]+, Calcd: 460.1550. Elem. anal. (C23H2IN7O2S • 0.2 CH2CI2) C,H,N,S.

Example 20: 9-Benzyl-6-benzylsulfanyl-8-morpholin-4-yl-9H-purine This compound was prepared according to general procedure C from 9- Benzyl-8-morpholino-6-mercaptopurine. Yield: 78 %. - Colourless oil. - 1H NMR (CDCI3) δ = 3.27 (t, 4H, J = 4.8, 2 x CH2N), 3.72 (t, 4H, J = 4.8, 2 x CH2O), 4.66 (s, 2H, CH2S), 5.31 (s, 2H, PhCH2N), 7.14-7.38 (m, 8H, CH Ph), 7.46 (m, 2H, CH Ph), 8.63 (s, 1 H, H-2). - 13C NMR (CDCI3) δ = 32.8, 46.7, 49.9, 66.1 , 126.4, 127.1 , 127.9, 128.4, 128.9, 129.1 , 129.6, 135.5, 137.6, 150.4, 150.7, 155.2, 156.4.

Example 21 : 9-Benzyl-6-benzylsulfanyl-8-pyrrolidin-1-yl-9H-purine This compound was prepared according to general procedure C from 9-Benzyl- 8-pyrrolidino-6-mercaptopurine. Yield: 48 %. - Colourless glass. - 1H NMR (CDCI3) δ = 1.83-1.95 (m, 4H, 2 x CH2CH2N), 3.52-3.68 (m, 4H, 2 x CH2N), 4.67 (s, 2H, CH2S), 5.45 (s, 2H, CH2N), 7.02-7.10 (m, 2H, CH arom), 7.21- 7.39 (m, 6H, CH arom), 7.43-7.52 (m, 2H, CH arom), 8.52 (s, 1 H, H-2). - 13C NMR (CDCI3) δ = 25.5, 32.9, 46.3, 49.5, 125.7, 127.0, 127.6, 128.3, 128.8, 129.1 , 136.5, 137.9, 148.8, 151.3, 151.5, 154.8, 158.5. HRMS (ESI) m/z Found: 402.1726 [M + H]+, Calcd: 402.1746. Elem. anal. (C23H23N5S • 0.15 CH2CI2) C1H1N1S. Assay All final products according to examples 1-17 were tested in the following radioligandbinding assay: Human erythrocyte membranes were used as a rich source of the nuleoside transport protein with [3H]NBTI as the radioligand (K0 value: 0.59 ± 0.07 nM).

• 100 ml compound or buffer • 10O mI [3H]NBTI 1.5 nM • 100 ml buffer (50 mM Tris.HCI,pH 7.4) • 100 ml erythrocyte membranes

After 30' incubation at 25 0C:

• filtration over Whatman GF/C filters (50 mM Tris.HCI used for washing) • filters in vials • 3.5 ml scintillation fluid • counting in beta counter after 2 hr

Data: