HRP990147A2 - Monocyclic l-nucleosides, analogs and uses thereof - Google Patents

Description

Field of invention

This invention is from the field of organic chemistry and biochemistry, it refers to the scientific field that deals with L-nucleosides.

State of the art

In the last few decades, significant efforts have been made to investigate the possibility of using D-nucleoside analogues as antiviral agents. Some of this work has borne fruit, and a number of nucleoside analogues are currently on the market as antiviral drugs, including HIV reverse transcriptase inhibitors (AZT, ddI, ddC, d4T and 3TC).

Nucleoside analogs have also been investigated as immune system modulators (Rennet, P. A. et al., J. Med. Chem, 36, 635, 1993), but again with less than entirely satisfactory results. For example, guanosine analogs such as 8-bromo-, 8-mercapto-, 7-methyl-8-oxoguanosine (Goodman, M. G. Immunopharmacology, 21, 51-68, 1991) and 7-thia-8-oxoguanosine (Nagahara, K. J. Med Chem., 33, 407-415, 1990; U.S. Pat. No. 5,0,41,426) have been investigated for years for their ability to activate the immune system. These guanosine derivatives have shown excellent antiviral and/or antitumor activity in vivo. But C8-substituted gonosins could not activate T-cells (Sharma, B. S. et al., Clin. Exp. Metastasis, 9, 429-439, 1991). The same applies to 6-arylpyrimidinones (Wierenga, W. Ann. N. Y. Acad. Sci., 685, 296-300, 1993). In other studies, a number of 3-deazapurine nucleosides were synthesized and tested as immune modulating agents. LOUSE. Patent No. 4,309,419 describes the use of 3-deazaadenosine as an inhibitor of the immune system. The β-D-nucleoside, β-2'-deoxy-3-deaza-guanosine (U.S. Pat. No. 4,950,647) exhibits the strongest possible immune-enhancing power on the activated T-cell response. Anti-inflammatory and immunosuppressive activity has also been described for some 2'-deoxynucleosides (EPO Application 0 038 569). However, these compounds undergo easy in vivo metabolic cleavage of the glycosyl bonds, which effectively deactivates their biological potency. Adenosine derivatives described in U.S. Pat. Pat. But. 4,148,888 are also catabolized in vivo by deaminase enzymes. In other studies, Levamisole, a thymomimetic immunostimulant (Hadden et al, Immunol. Today, 14, 275-280, 1993), appears to act on the T-cell lineage in a manner similar to thymic hormones. Tucarezole (Reitz et al, Nature, 377, 71-75, 1995), another T-cell stimulant is now undergoing clinical trials. More recently, a 6-substituted purine amino acid linker (Zacharie et al, J. Med. Chem., 40, 2883-2894, 1997) has been described as a promising immunostimulant that can be targeted for those diseases that require an increased CTL or Th1 response. type.

One possible target of immunomodulation involves the stimulation or suppression of Th1 and Th2 lymphokines. Type 1 (Thl) cells produce interleukin 2 (IL-2), tumor necrosis factor (TNFα) and interferon gamma (IFNγ) and are primarily responsible for cellular immunity such as delayed-type hypersensitivity and antiviral immunity. Type 2 (Th2) cells produce interleukins, ILA, IL-5, IL-6, IL-9, IL-10, and IL-13, and are primarily involved in assisting the humoral immune response such as that seen in allergens, eg, IgE and IgG4 isotype switching antibodies (Mosmann, 1989, Annu Rev Immunol, 7:145-173). D-guanosine analogues have been shown to exhibit differential effects on the lymphokines IL-1, IL-6, IFNα and TNFα (indirectly) in vitro (Goodman, 1988, Int J Immunopharrnacol, 10, 579-88) and in vivo (Smee et al. al., 1991, Antiviral Res 15: 229). However, the ability of D-guanosine analogs such as 7-thio-8-oxoguanosine to modulate type I or type II cytokines directly in T-cells has been ineffective or has not been described.

It is significant that research on small molecules has focused on the synthesis and testing of D-nucleosides. These include ribavirin (Witkowski, J. T. et al., J. Med Chem., 15, 1150, 1972), AZT (De Clercq, E. Adv. Drug Res., 17, 1, 1988), DDI (Yarchoan, R. et al., Science (Washington, D. C.), 245, 412, 1989), DDC (Mitsuya, H. et al., Proc. Natl. Acad Sci. U. S. A., 83, 1911, 1986), d4T (Mansuri, M. M. et al. al., J. Med. Chem., 32, 461, 1989) and 3TC (Doong, S. L. et al., Proc. Natl. Acad. Sci. U.S.A., 88, 8495-8599, 1991). Among this plethora of therapeutic agents, only 3TC is one that contains an artificially modified L-ribose moiety, the enantiomer of natural D-ribose.

After 3TC was approved by the FDA, papers were published on a number of nucleosides with an artificial L-configuration as possible chemotherapeutic agents against the immunodeficiency virus (HIV), hepatitis B virus (HBV), and some forms of cancer. These include (-)-β-L-1-(2-(hydroxymethyl)-1,3-oxathiolan-4-yl]-5-fluorocytosine (FTC; Furman, P. A., et al, Antimicrob. Agents Chemother., 36 , 2686-2692, 1992), (-)-β-L-2',3'-dideoxypentofuranosyl-5-flurocytosine (L-FddC; Gosselin, G., et al, Antimicrob. Agents Chemother., 38, 1292- 1297, 1994), (-)-β-L-1-[2-(hydroxymethyl)-1,3-oxathiolan-4-yl]cytosine [(-)-OddC; Grove, K. L., et al, Cancer Res. , 55, 3008-3011, 1995], 2',3'-dideoxy-β-L-cystidine (β-L-ddC; Lin, T.S., et al, J. Med. Chem., 37, 798-803, 1994), 2'-fluoro-5-methyl-β-L-arabinofuranosyluracil (L-FMAU; U.S. Pat. No. 5,567,688), 2',3'-dideoxy-2',3'-didehydro-β-L- cystidine (β-L-d4C; Lin, T.S., et al, J. Med Chem., 39, 1757-1759, 1996), 2',3'-dideoxy-2',3'-didehydro-β-L- 5-fluorocystidine (β-L-Fd4C; Lin, T.S., et al, J. Med Chem., 39, 1757-1759, 1996), L-cyclopentyl carbocyclic nucleosides (Wang, P., et al, Tetrahedron Letts., 38, 4207-4210, 1997) and a series of 9-(2'-deoxy-2'-fluoro-β-L-arabinofuranosyl)purine nucleosides (Ma, T.' et al, J. Med. Chem., 40, 2750-2754, 1997).

Other studies of L-nucleosides have been published. LOUSE. Pat. But. 5,009,698, for example, describes the synthesis and use of L-adenosine to stimulate plant growth. WO 92/08727 describes some L-2'-deoxyuridines and their use for the treatment of viruses. Spadari, S., et al, J. Med Chem., 35, 4214-4220, 1992, describes the synthesis of some L-β-nucleosides useful in the treatment of viral infections including herpes simplex virus type I. U.S. Pat. But. 5,559,101 describes the synthesis of α- and β-L-ribofuranosyl nucleosides, the procedures for their preparation, the pharmaceutical composites containing them, and the method of their use in the treatment of various mammalian diseases. A German patent (De 195 18 216) describes the synthesis of 2'-fluoro-2'-deoxy-L-β-arabinofuranosyl pyrimidine nucleosides. LOUSE. Pat. Nose. 5,565,438 and 5,567,688 describe the synthesis and use of L-FMAU. WO Patent 95J20595 describes the synthesis of 2'-deoxy-2'-fluoro-L-β-arbinofuranosyl purine and pyrimidine nucleosides and a method of treating HBV or EBV. LOUSE. Pat. But. 5,567,689 describes methods for increasing uridine levels with L-nucleosides. WO patent 96/28170 describes a method of reducing the toxicity of D-nucleoside by simultaneous administration of an effective amount of L-nucleoside compounds.

Notably, although some of the known L-nucleosides exhibit possible antiviral activity with less toxicity profiles than their D-analogues, none of these L-nucleoside compounds possess immunomodulating properties. Moreover, there is currently no effective treatment for modulating the immune system when lymphokine profiles (Th1 and Th2 subsets) are involved. Thus, there is a need for new L-nucleoside analogs, especially a need for L-nucleoside analogs that modulate the immune system, and above all for L-nucleoside analogs that specifically modulate Th1 and Th2.

Brief description of the invention

This invention relates to novel L-nucleoside compounds, their therapeutic use and synthesis.

In one aspect of the present invention, novel L-nucleoside compounds are provided according to the following formula:

[image]

where:

A is independently selected from N and C;

B, C, E and F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamines, COCH 3 , lower alkyl alkenyl, lower alkyl vinyl or lower alkyl aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamines, lower alkyl alkenyl, lower alkyl vinyl, lower alkyl aryl or substituted heterocyclic compounds;

D is independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2, P or none, where R1 is independently H, O, lower alkyl, lower alkylamines, COCH3, lower alkyl alkenyl , lower alkyl vinyl or lower alkyl aryl, and R 2 is independently H, OH, halogens, CN, N 3 , NH 2 , lower alkyl, lower alkylamines, lower alkyl alkenyl, lower alkyl vinyl, lower alkyl aryl or substituted heterocyclic compounds;

X is independently O, S, CH 2 or NR; where R is COCH3;

R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl and lower alkyl amines;

R2, R3, R5, R6, R7 and R8 are independently selected from the group consisting of H, OH, CN, N3, halogens, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkyl amines and substituted heterocyclic compounds; and

R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are not all simultaneously substituted; so

when R2 = R3 = H, then R7 and R8 are hydrogen or none;

when R 1 , R 4 or R 5 are substituted, then R 7 = R 8 = H and R 2 = R 3 = OH;

when R 2 or R 3 are substituted, then R 7 and R 8 are equal to H or OH;

when R 7 or R 8 are substituted, then R 2 and R 3 are equal to H or OH;

when R7 and R8 are hydroxyl, then R2 and R3 are not OH;

when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is a CH or C-substituent; F = CH; X = O, S or CH2, then R2 will not be H, OH, CH3, halogen, N3, CN, SH, SPh, CH2OH, CH2OCH3, CH2SH, CH2F, CH2N3, aryl, aryloxy or heterocyclic;

when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is CH, C-CH3 or halogen; F = CH;

X = N-COCH3, then R2 will not be H or OH;

when A = N; B = CH; C = CH or CH3; D = CH or C-CH3; E is CH, C-CH3 or C-CONH2; F = CH; X = O or CH2, then R2 will not be H or OH;

when A = N; B = N, CO or CH; C = CH, C-Cl or C-OCH3; D = CH or C-Ph; E is CH, C-Cl or C-Ph; F = N or CO; X = O, then R 2 will not be H or OH;

when A = N; B = CO or CS; C = N or NH; D = CO or C-NH2; E is CH or N; F = N or CH; X = O, then R 2 will not be H or OH; and

when A = C; B = CH; C = NH; D = CO, CS or C-NH2; E is N or NH; F = CO or CH; X = O, then R 2 will not be H or OH.

In one class of preferred embodiments of this invention, the compound contains a ribofuranosyl moiety, and in a particularly preferred embodiment, the compound contains L-ribavirin.

In a further aspect of the present invention, the pharmaceutical composite comprises a therapeutically effective amount of a compound of formula 1 and 3-5, or a pharmaceutically acceptable ester or salt thereof, which is mixed with at least one pharmaceutically acceptable carrier.

In a further aspect of this invention, a compound according to formulas 1 and 3-5 is used in the treatment of any condition that has a positive response to the administration of the compound, and accordingly to any formulation or protocol that achieves a positive response. Among other things, it is understood that the compounds of formula I can be used to treat infection, infestation, cancer or tumor or autoimmune disease.

Brief description of the drawing

Figures 1-12 are schematic representations of the steps in chemical synthesis that can be used to prepare the compounds in the "Examples" chapter.

Figures 13-14 are graphical representations of the effects of D-ribavirin and L-ribavirin on IL-2 TNFα, IFN-β, IL-4 and IL-5 levels of activated T-cells.

Figure 15 is a graphic representation of the description. In another set of experiments, the effects of D-ribavirin on the inflammatory response of the ear to dinitrofluorobenzene were determined.

Full description

The following terms are used in this publication, with the definitions listed below:

The term "nucleoside" refers to compounds that are composed of a pentose or modified pentose species that is attached to a specific position of the hetecyclic ring or to the natural position of a purine (position 9) or pyrimidine (position 1) or to an equivalent position in an analog.

The term "nucleotide" refers to a monovalent saturated or unsaturated carboxyl radical that has at least one heteroatom, such as N, O or S, whereby each available position within the ring can be arbitrarily substituted, independently, for example with hydroxy, oxo, amino, imino, lower alkyl, bromine, chlorine and/or cyano. Within this class of substituents are purines, pyrimidines.

The term "purine" refers to nitrogen bicyclic heterocyclic compounds.

The term "pyrimidine" refers to nitrogen monocyclic heterocyclic compounds.

The term "D-nucleosides" as used herein describes nucleoside compounds having D-ribose (eg, adenosine) as a carbohydrate moiety.

The term "L-nucleosides" used in this invention describes nucleoside compounds having L-ribose as a carbohydrate moiety.

The term "L-configuration" as used herein in this invention describes the chemical configuration of the ribofuranosyl portion of the compounds which is attached to the nucleic base. The L-configuration of the carbohydrate moiety of the compounds of this invention contrasts with the D-configuration of the carbohydrate moiety - ribose in naturally occurring nucleosides such as cytidine, adenosine, thymidine, guanosine and uridine.

The term "C-nucleosides" used in this publication describes the type of linkage between the carbohydrate moiety - ribose and the heterocyclic base. In C-nucleosides, the bond starts from the C-1 position of the carbohydrate part - ribose and is attached to the carbon of the heterocyclic base. The bond that exists in C-nucleosides is carbon-carbon type.

The term "N-nucleosides" used in this publication describes the type of bond between the carbohydrate moiety - ribose and the heterocyclic base. In N-nucleosides, the bond starts from the C-1 position of the carbohydrate part - ribose and binds to the carbon of the heterocyclic base. The bond that exists in N-nucleosides is of the carbon-nitrogen type.

The term "protecting group" refers to a chemical group that is attached to an oxygen or nitrogen atom to prevent further reaction during the formation of derivatives or other species in the molecule containing the oxygen or nitrogen. A whole series of oxygen or nitrogen protecting groups is known, which is known to those involved in organic synthesis.

The term "lower alkyl" refers to methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, and butyl or n-hexyl. The term further refers to cyclic, branched or unbranched chains of one to six carbon atoms.

The term "aryl" refers to a monovalent unsaturated aromatic carbon cyclic radical having one ring (eg, phenyl) or two fused rings (eg, naphthyl), which may be optionally substituted with hydroxyl, lower alkyl, chlorine, and/or cyano.

The term "heterocyclic compound" refers to a monovalent saturated or unsaturated carbon cyclic radical that has at least one heteroatom, such as N, O, S, Se or P, and any available position within the ring that can be arbitrarily substituted or unsubstituted, independently, eg with hydroxy, oxo, amino, imino, lower alkyl, bromine, chlorine and/or cyano group.

The term "monocyclic compound" refers to a monovalent saturated carbon cyclic radical having at least one heteroatom, such as N, O, S, Se or P, and any available position within the ring that can be arbitrarily substituted, independently, by a carbohydrate moiety or some other group such as chlorine, bromine and/or cyano group, so that the monocyclic ring is optionally aromatized (eg thymidine; 1-(2'-deoxy-β-D-erythro-pentofuranosyl)thymine).

The term "immunomodulators" refers to natural or synthetic products that can alter normal or abnormal immune systems through stimulation or suppression.

The term "effective amount" refers to an amount of a compound of formula (I) that can restore immune function to normal levels, or increase immune function above normal levels to clear an infection.

Compounds of formula I may have multiple asymmetric centers. Accordingly, they can be prepared as an optically active form or as a racemic mixture. The scope of the invention as described and stated in the claims includes individual optical isomers or their non-racemic mixtures as well as racemic forms of the compounds of formula I.

The terms "α" and "β" refer to the specific stereochemical configuration of the substituent on the symmetrical carbon atom in the chemical structure as shown. The compounds described herein are all of the L-furanosyl configuration.

The term "enantiomers" refers to a pair of stereoisomers that are non-superimposable mirror images of each other. A mixture of a pair of enantiomers in a 1:1 ratio is a "racemic" mixture.

The term "isomers" refers to different compounds that all have an identical formula.

"Stereoisomers" are isomers that differ only in the way the atoms are arranged in space.

"Pharmaceutically acceptable salt" can be any salt derived from an inorganic or organic acid or base.

The compounds of this invention are named according to the formula II convention.

[image]

Dates

The compounds of this invention are generally described by formula I. There are, however, several subsets of compounds of particular interest, including compounds according to formulas III, IV and V, which are listed below.

Compounds of formula III have the following structures:

[image]

where:

X is independently O, S, CH 2 and NR, where R is COCH 3 ;

R' and R" are independently selected from H, CN, C(=O)NH2, NH2, C(=S)NH2, C(=NH)NH2⋅HCl, C(=NOH)NH2, C(=NH) OMe, heterocyclic compounds, halogen, lower alkyl or lower alkyl-aryl;

R 2 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl or lower alkyl-amine; and

R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkyl-amine or substituted heterocyclic compounds; so that when R2 = R3 = H, then R7 and R8 are hydrogen or none.

In compounds of formula III, R' is preferably carboxamide or CN and R" is hydrogen or halogens; R1 = R4 = R5 = R7 = R8 = H and R2 = R3 = OH, and preferably X is oxygen.

Compounds according to formula IV have the following formulas:

[image]

where:

A is independently selected from N or C;

B, C, E and F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2⋅HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamine, lower alkyl-alkenyl, lower alkyl-vinyl, lower alkyl aryl or substituted heterocyclic compound;

X is independently O, S, CH 2 or NR; where R is COCH3;

R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl or lower alkyl-amine; and

R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, NH2, CH2OH, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, allyl, lower alkyl, lower alkyl-amine or a substituted heterocyclic compound; so

when R2 = R3 = H, then R7 and R8 are hydrogen or none;

when A is carbon; B = E = N; C is N-Ph, then F is not CH;

when A = N; C is CH; B = E = C-CH3, then F is not nitrogen; and

when A is carbon, B = N; C = C-CONH2; E = CH; F = S, then X is not CH2.

In the compounds of formula IV, R 1 is preferably H, lower alkyl or allyl; R2 is preferably H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2 or C(=NH) OMe; and when R1 = R4 = R5 = R7 = R8 = H, then preferably R2 = R3 = OH and X is preferably oxygen.

Compounds according to formula V have the following structure:

[image]

where:

A is independently selected from N or C;

B, C, E, F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(-O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamine, lower alkyl-alkenyl, lower alkyl-vinyl, lower alkyl-aryl or substituted heterocyclic compound;

D is independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2, P or none; R 1 is independently H, O, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R 2 is independently H, OH, halogens, CN, N 3 , NH 2 , lower alkyl, lower alkylamine, lower alkyl alkenyl, lower alkyl-vinyl, lower alkyl-aryl or a substituted heterocyclic compound;

X is independently O, S, CH 2 or NR where R is COCH 3 ;

R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl and lower alkyl-amine; and

R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkylamine and substituted heterocyclic compound; so

when R2 = R3 = H, then R7 and R8 are hydrogen or none.

when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is a CH or C-substituent; F = CH; X = O, S or CH2, then R2 will not be H, OH, CH3, halogens, N3, CN, SH, SPh, CH2OH, CH2OCH3, CH2SH, CH2F, CH2N3, aryl, aryloxy or heterocyclic.

when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is CH, C-CH3 or halogen; F = CH; X = N-COCH3, then R2 will not be H or OH;

when A = N; B = CH; C = CH or CH3; D = CH or C-CH3; E is CH, C-CH3 or C-CONH2; F = CH; X = O or CH2, then R2 will not be H or OH;

when A = N; B = N, CO or CH; C = CH, C-Cl or C-OCH3; D = CH or C-Ph; E is CH, C-Cl or C-Ph; F = N or CO; X = O, then R 2 will not be H or OH;

when A = N; B = CO or CS; C = N or NH; D = CO or C-NH2; E is CH or N; F = N or CH; X = O, then R 2 will not be H or OH; and

when A = C; B = CH; C = NH; D = CO, CS or C-NH2; E is N or NH; F = CO or CH; X = O, then R 2 will not be H or OH.

A particular class of compounds intended to be included herein includes nucleoside analogs containing a ribofuranosyl moiety where the carbohydrate is of the L-configuration rather than the native D-configuration. This class includes compounds containing altered natural nucleic acid bases and/or synthetic nucleoside bases such as triazole, 3-cyano-1,2,4-triazole, methyl 1,2,4-triazole-3-carboxylate, 3-bromo -5-nitro-1,2,4-triazole, imidazole, 2-nitroimidazole, 2-bromo-4(5)-aminoimidazole, pyrazole, 3(5)-aminopyrazole-4-carboxamide, triazines, pyrrole, pyridine, azapyridine , thiazole, 1,2,5-thiadiazole, selenadiazole, 4-amino-1,2,5-thiadiazole-3-carboxylic acid, methyl-4-oxo (5H)-1,2,5-thiadiazole-3-carboxylate , 4-amino-1,2,5-selenadiazole-3-carboxylic acid, tetrazole, azaphosphole, 4-amino-1,3-azaphosphole-5-carbonitrile, 4-bromo-1,3-azaphosphole-5-carbonitrile, 2-aminophosphine-3-carbonitrile, methyl 2-amino-3-cyano-phosphole-4-carboxylate, 4,5-dicyano-1,3-diazaphosphole, diazaphosphole, isoxazole, 3-oxo-(2H)-isothiazole-3 -carboxylic acid, 5-amino-3-chloroisothiazole-4-carbonitrile, 5-methylthio-3-oxo-(2H)-isothiazole-4-carbonitrile, isothiazole, pyrimidine and other substituted derivatives of these bases. Compounds of this class may also independently contain other hetero-monocyclic bases and their derivatives, certain modifications of the ribofuranosyl part, and N- and C-linked L-nucleosides.

Particularly preferred compounds of this class include L-ribavirin, 1-β-L-ribofuranosyl-1,2,4-triazole-3-carboxamide. L-ribavirin is shown in Figure I where A, B and E are nitrogen; C is C-C(O)NH 2 ; D is nothing; F is CH; X is oxygen; R 1 , R 4 , R 5 , R 7 and R 8 are hydrogen; and R 2 , R 3 and R 6 are hydroxyl.

Ribavirin (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a monocyclic synthetic D-nucleoside that has shown activity against a wide range of viral diseases (Huffman et al, Antimicrob. Agents Chemother. , 3, 235, 1975; Sidwell et al, Science, 177, 705, 1972) and is currently undergoing clinical trials in conjunction with γ-interferon for the treatment of hepatitis C. In the past two decades, a variety of ribavirin D-nucleoside analogs have been used and most of them showed exceptional antiviral and antitumor activity. However, there are no published works on the synthesis of L-isomer ribavirin analogs and their biological activity. In X-ray structural analysis using the single crystal technique, ribavirin structurally resembles guanosine (Prusiner et al., Nature, 244, I 16, 1973). Because of ribavirin's similarity to guanosine, we expected ribavirin nucleoside analogs to exhibit similar or better immune-modulating activity than guanosine analogs (Robins et al, US 5,041,426) in addition to antiviral activity.

Use

It is to be understood that the compounds of this invention will be used to treat a wide range of conditions, in fact any condition that has a positive response to the administration of one or more of these compounds. Among other things, it is particularly understood that the compounds of this invention can be used for the treatment of infection, infestation, cancer or tumor or autoimmune disease.

Infections contemplated to be treatable by the compounds of this invention include respiratory syncytial virus (RSV), hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex types 1 and 2, herpes genitalis, herpes keratitis, herpes encephalitis, herpes zoster, human immunodeficiency virus (HIV), influenza A virus, Hantan virus (hemorrhagic fever), human papilloma virus (HPV), measles and fungus.

Infestations believed to be treatable with the compounds of this invention are protozoan infestations as well as helminths and other parasitic infections.

Carcinomas and tumors thought to be treatable include those caused by a virus, and the effect may include inhibiting the conversion of virus-infected cells to a neoplastic state, inhibiting the spread of the virus from the altered cells to other normal cells, and/or stopping the growth of the virally altered cells.

Autoimmune and other diseases considered to be treatable include arthritis, psoriasis, stomach ailments, juvenile diabetes, multiple sclerosis, gout and gouty arthritis, rheumatoid arthritis, organ transplant rejection, allergy and asthma.

Further implied uses of the compounds of this invention include their use as intermediates in the chemical synthesis of other nucleoside or nucleotide analogs which, again, are useful as therapeutic agents for other purposes.

In a further aspect, the method of treating a mammal includes administering a therapeutically and/or prophylactically effective amount of a pharmaceutical comprising a compound of the present invention. Regarding this aspect, the effect may be related to the modulation of some part of the mammalian immune system, in particular to the modulation of Th1 and Th2 lymphokine profiles. When modulation of Th1 and Th2 lymphokines occurs, it is thought that the modulation may involve stimulation of Th1 and Th2, stimulation of either Th1 or Th2 and suppression of the other, or bimodal modulation whereby an effect at Th1/Th2 levels (such as generalized suppression) occurs at a lower concentration, while another effect (such as stimulation of either Th1 or Th2 and suppression of the other) occurs at a higher concentration.

In general, the most preferred applications according to the present invention are those where the active compounds are relatively less cytotoxic to non-targeted host cells and relatively more active to the target. In this regard, it is also advantageous if L-nucleosides are of increased stability compared to D-nucleosides, which may lead to better pharmacokinetics. This result can be achieved because L-nucleosides cannot be recognized by enzymes, and therefore they can have a longer half-life.

It is understood that the compounds of this invention will be administered in any suitable pharmaceutical formulation and under any agreed protocol. Accordingly, administration may be oral, parenteral (including subcutaneous injection, intravenous, intramuscular, intrasternal injection or infusion technique), inhalation spray or rectally, topically, etc., and in unit dose formulations containing suitable non-toxic pharmaceutically acceptable carriers, adjuvants and drivers.

By way of example, it is understood that the compounds of the present invention may be formulated in admixture with a pharmaceutically acceptable carrier. For example, the compounds of this invention can be administered orally as pharmaceutically acceptable salts. Since the compounds of this invention are mostly water soluble, they can be administered intravenously in saline (eg, buffered to a pH of about 7.2 to 7.5). Common buffers such as phosphates, bicarbonates or citrates can be used for this purpose. Of course, one of ordinary skill in the art can vary the formulations within the specifications to obtain numerous formulations for a particular route of administration without rendering the composites of this invention unstable nor affecting their therapeutic activity. In particular, modifications of these compounds with the intention of making them more soluble in water or another medium, for example, can be easily achieved by minor changes (salt composition, esterification, etc.) which are well known to those skilled in the art. It is also known, within the standard techniques of the art, how the route of administration or dosage regimen for a particular compound can be changed to manage the pharmacokinetics of these compounds in order to achieve maximum beneficial effect in the patient.

For certain pharmaceutical dosage forms, the prodrug form of the compounds, especially that which includes acylated (acetylated or other) derivatives, pyridine esters and various salt forms of these compounds are preferred. Those skilled in the art know how to easily change these compounds into pro-drug forms to facilitate delivery of the active compounds to the target site within the host or patient organism. Those skilled in the art may also take advantage of the favorable pharmacokinetic parameters of the pro-drug form upon administration of the compound to a target site within the host or patient to maximize the desired effect of the compound.

Furthermore, the compounds according to the present invention can be used alone or in combination with other substances in the treatment of the above-mentioned infections or conditions. Combined therapies according to the present invention include the administration of at least one compound of the present invention or its functional derivative and at least one other pharmaceutically active supplement. The amount of active additive(s) and pharmaceutical active substance and the relative times of administration will be selected so as to achieve the desired therapeutic effect. Preferably, the combination therapy includes the administration of one compound of the present invention or a functional derivative thereof and one agent listed below.

Further examples of such therapeutic agents effective in modulating the immune system or related conditions include such as AZT, 3TC, 8-substituted guanosine analogs, 2',3'-dideoxynucleosides, interleukin II, interferons such as γ-interferon, tucaresol , levamisole isoprinosine and cyclolignans. Some compounds according to this invention may be effective for enhancing the biological activity of certain agents according to this invention by reducing metabolism or deactivating other compounds, and as such they are applied in parallel for this desired effect.

Regarding dosage, one skilled in the art knows that the therapeutically effective amount varies and depends on the infection or condition being treated, its advanced stage, the treatment regimen being used, the pharmacokinetics of the agent being used, and the patient (animal or human) being treated. heals. An effective dose may range from 1 mg/kg body weight, or less, to 25 mg/kg body weight or more. In general, a therapeutically effective dose of this compound in a dosage form typically ranges from slightly less than 1 mg/kg to about 25 mg/kg for a patient, depending on the compound being used, the condition or infection being treated, and the route of administration. This dosage range usually provides an effective blood concentration level of the active compound in the range of about 0.04 to about 100 micrograms/cc of the patient's blood. It is understood, however, that an adequate regimen can be achieved by applying a small amount, and increasing the amount until the side effects become undesirably harmful, or the desired effect is achieved.

Administration of the active compound may vary from continuous administration (intravenous drip) to several oral administrations per day (eg, Q.I.D.) and may include oral, topical, parenteral, intramuscular, subcutaneous, transdermal (which may include a penetration enhancer) and buccal administration, and the use of suppositories, among other routes of administration.

To prepare pharmaceutical compositions according to the present invention, a therapeutically effective amount of one or more compounds according to the present invention is preferably well mixed with a pharmaceutically acceptable carrier according to conventional pharmaceutical binding techniques to form a dosage. The carrier can be in a variety of forms, depending on the form of preparation desired for administration, eg oral or parenteral. When preparing pharmaceutical composites for oral administration, any of the usual pharmaceutical media can be used. Accordingly, for liquid oral preparations such as suspensions, elixirs and solutions, suitable carriers and additives include water, glycols, oils, alcohols, flavor enhancers, preservatives, coloring agents and the like. For solid oral preparations such as powders, tablets, capsules and for solid preparations such as suppositories, suitable carriers and additives include starch, carbohydrate carriers such as dextrose, mannitol, lactose and related carriers, diluents, granulating agents, lubricants, agents for decomposition and the like. If desired, tablets or capsules can be enteric-coated or delayed-release, using standard techniques.

For parenteral formulations, the carrier usually consists of sterile water or aqueous sodium chloride, although other additives, including those that aid dispersion, may be added. of course, if sterile water is used and kept sterile, then composites and supports should also be sterilized. Injectable suspensions can also be prepared, in which case suitable liquid carriers, suspending agents and the like can be used.

Test results

In vitro and in vivo tests were performed on the compounds of formula I, L-ribavirin, and the results are listed below.

In the first series of experiments, peripheral blood mononuclear cells (PBMCs) were isolated, after which 60 ml of blood from healthy donors was subjected to Ficoll-Hypaque density gradient centrifugation. T cells were then purified from PBMCs using Lymphokwik T-cell-specific lymphocyte isolation reagent (LK-25T, One Lambda, Canoga Park CA). An average of 40-60×106 T-cells were then incubated overnight at 37°C in 20-30 ml RPMI-APS (RPMI-1640 medium (ICN, Costa Mesa, CA) containing 20 mM HEPES buffer, pH 7.4 , 5% autologous plasma, 1% L-glutamine, 1% penicillin/streptomycin, and 0.05% 2-mercaptoethanol) to remove cells with adherent debris. In all experiments, T cells were washed with RPMI-APS and then plated in a 96-well microtiter plate at a cell concentration of 1 × 10 6 cells/ml.

T-cells were activated by the addition of 500 ng of ionomycin and 10 ng of phorbol 12-myristate 13-acetate (PMA) (Calbiochem, La Jolla, CA) and incubated for 48-72 h at 37°C. PMA/ionomycin-activated T-cells were treated with 0.5-50 pM of the L-guanosine tested, or with 250-10000 U/ml of the control antiviral, interferon-alpha (Accurate, Westbury, NY) immediately after activation and retreated after 24 an hour. T-cells from each plate were used for immunofluorescence analysis, and the supernatant was used for extracellular cytokine measurements. After activation, 900 μl of cell supernatant from each microplate was transferred to the next microplate for analysis of cellular cytokine production. Cells were then used for immunofluorescence analysis of intracellular cytokine levels and cytokine receptor expression.

Cell-derived human cytokine concentrations were determined in the cell supernatants of each microplate. Activation-induced changes in interleukin-2 (IL-2) levels were determined by a commercially available ELISA kit (R&D systems Quantikine kit, Minneapolis, MN) or by bioassay using an IL-2-dependent cell line, CTLL-2 (ATCC, Rockville, MD). . Activation induced changes in interleukin-4 (IL-4), tumor necrosis factor (TNFα) interleukin-8 (IL-8) (R & D systems (Quantikine kit, Minneapolis, MN), and interferon-gamma (IFN-γ) levels ( Endogen (Cambridge, MA) were determined using an ELISA kit All ELISA results are expressed in pg/ml and CTLL-2 bioassays as pulses per minute representing IL-2-dependent cellular incorporation of 3H-thymidine (ICN, Costa Mesa, CA ) using CTLL-2 cells.

A comparison of the effects of D-ribavirin and L-ribavirin (expressed as a percentage of the activated control) on IL-2 TNFα, IFN-γ, IL-4 and IL-5 levels is shown in Figures 13 and 14.

In the following series of experiments, the effects of L-ribavirin on the inflammatory response of the ear to dinitrofluorobenzene were determined. The results of these experiments are shown in Figure 15.

Synthesis

The compounds of this invention may be prepared according to synthetic methods which are individually well known to those skilled in the art. In general, the compounds of this invention can be synthesized by fusing the appropriate nucleoside base with the required carbohydrate synthon to give a protected L-nucleoside which, after subsequent manipulations and removal of the hydroxyl protecting group, finally yields a nucleoside analog having the desired robofuranosyl moiety of the L-configuration.

During the chemical synthesis of various composites according to this invention, one skilled in the art will be able to carry out this invention without undue experimentation. In particular, one skilled in the art will know the various steps that will need to be performed to introduce a particular substituent at a desired position of a base or a substituent at a desired position of a carbohydrate moiety.

Further, chemical steps designed to protect functional groups such as hydroxyl or amino groups, among others, as well as to deprotect these same functional groups, will be seen as appropriate within the circumstances of the synthesis.

The invention is further defined by reference to the following examples, which are intended to be illustrative and not limiting. One skilled in the art will recognize that the examples are in no way limiting and that changes in detail may be made without departing from the spirit and scope of the present invention.

The compounds of this invention can be prepared according to well-known procedures well known in the art. The following synthesis schemes are particularly useful:

Scheme 1: Synthesis of ribofuranosyl (R1, R4, R5, R7 and R8 are hydrogen; R2, R3 and R6 are hydroxyl) nucleosides of formula (II): Triazole L-ribofuranosyl nucleosides were prepared by an acid-catalyzed coupling process (Sato, T., et al, Nippon Kagaku Zasshi, 81, 1440, 1960. Accordingly, triazoles (1) were mixed with 1,2,3,5-tetra-O-acetyl-L-ribose (2) and a catalytic amount of bis(p- nitrophenyl)phosphate and heated to 160-165°C for 30 min under reduced pressure to obtain the necessary nucleosides which, after subsequent deprotection, give triazole L-ribonucleosides (3) of formula (II).

[image]

Scheme I

Scheme 2: Synthesis of L-ribofuranosyl (R1, R4, R5, R7 and R8 are hydrogen; R2, R3 and R6 are hydroxyl) nucleosides of formula (III): Triazole, pyrazole and other 5-membered heterocyclic L-ribofuranosyl nucleosides of this invention prepared are by Vorbruggen's procedure which involves treatment of the heterocyclic compound (4) with chlorotrimethylsilane to give a silyl intermediate which after condensation with protected ribose (5) in the presence of stannous chloride in an inert solvent gives the desired nucleoside (6). After condensation, the product is deprotected by conventional methods known to those skilled in the art, and becomes the compound of formula (III):

[image]

Scheme II

Most of the compounds of formula (III) were prepared using the above-mentioned condensation procedure. The desired 1,2,3,5-tetra-O-acetyl-L-ribose and 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribose were prepared as shown in Example 2, i.e., Example 13. Hetero-monocyclic bases are commercially available from Aldrich, Fluka, ICN, Acros, Alfa, Lancaster, and TCI America or prepared by the following published procedure found in the literature (Robins, R. K., et al, Nucleosides & Nucleotides, 13, 17-76, 1994). The preparation of pyrrole, pyrazole, or triazole L-nucleosides of other types of formula (IV) can be carried out by the following procedures outlined for the preparation of the corresponding D-nucleosides in Chemistry of Nucleosides and Nucleotides, published by Leroy B. Townsend, New York, Plenum Press, 3, I-105, 1994. Various imidazole L-nucleosides were prepared by the following published methods into imidazole D-nucleosides (Shaw, G., in Chemistry of Nucleosides and Nucleotides, ed. Leroy B. Townsend, New York, Plenum Press, 3, 263- 420, 1994).

Scheme 3: Compounds of formula (I) can be prepared by reacting heterocyclic compounds (7) with L-ribose (5) by the following Vorbruggen procedure (Niedballa, U., et al, J. Org. Chem., 39, 3654, 1974 ) described above for the preparation of compounds of formula (III).

[image]

Scheme 3

C-nucleosides (wherein A is carbon in formulas I and III) of the L-configuration were prepared using the method published (Watanabe, K. A., in Chemistry of Nucleosides and Nucleotides, published by Leroy B. Townsend, New York, Plenum Press, 3, 421-535 , 1994) to prepare their corresponding D-configuration C-nucleosides.

Scheme 4: Preparation of L-arabinofuranosyl nucleosides (R1, R2, R4, R5 and R8 are hydrogen; R3, R6 and R7 are hydroxyl): β-anomers of arabinosyl L-nucleosides of formula (I-III) can be prepared by reaction 2 . -nucleosides (10). Removal of the blocking group 10 should give the desired β-L-arabinofuranosyl nucleosides. In the case of pyrrolic β-L-arabinucleosides, the sodium salt glycosylation procedure is followed (Revankar, G. R., et al, Nucleosides & Nucleotides, 6, 261-264, 1987).

[image]

Scheme 4

Scheme 5: Preparation of L-xylofuranosyl nucleosides (R1, R3, R4, R5 and R7 are hydrogen; R2, R6 and R8 are hydrogen): β-anomers of xylofuranosyl L-nucleosides of formula (I-III) can be prepared from 1,2 -di-O-acetyl-3,5-di-O-benzyl-L-xylofuranose 11; Gosselin, G., et al., J. Heterocyclic Chem., 30, 1229-1233, 1993) and the corresponding bases, following a method analogous to that described for Scheme 4.

[image]

Scheme 5

Scheme 6: Preparation of L-2'-deoxyribofuranosyl nucleoside (R1, R2, R4, R5, R7 and R8 are hydrogen; R3 and R6 are hydroxyl): β-anomers of 2'-deoxyribofuranosyl L-nucleoside of formula (I-III) can are prepared by the reaction of 3',5'-di-O-p-toluyl-2'-deoxyerythro-β-L-pentofuranosyl chloride (13) (Smejkal, J., et al, Collect. Czec. Chem. Commun. 29, 2809- 2813, 1964) with the silyl derivative of the heterocyclic compound in the presence of a Bronsted acid to give exclusively the β-isomer (14) in good yield (Fujimori, S., et al, Nucleosides & Nucleotides, 11, 341-349, 1992; Aoyama , H., Bull. Chem. Soc., 60, 2073, 1987). Identical β-L-2'-deoxyribofuranosyl nucleosides were also prepared by reaction of the chlorocarbohydrate (13) with the sodium salt of the base (Kazimierczuk, Z., et al, J. Amer. Chem. Soc., 106, 6379-6382, 1984) in dry acetonitrile. Intermediate (14) after treatment with methanolic ammonia gives the desired β-L-2'-deoxyerythro-pentofuranosyl nucleoside.

[image]

Scheme 6

Scheme 7: Preparation of L-3'-deoxyribofuranosyl nucleoside (R1, R3, R4, R5, R6, R7 and R8 are hydrogen; R2 and R6 are hydroxyl): β-anomers of 3'-deoxyribofuranosyl L-nucleoside of formula (I-III ) can be prepared by reacting 1,2-di-O-acetyl-5-O-benzoyl-3-deoxy-L-erythro-pentose 1(-) with a silyl derivative of a heterocyclic compound in the presence of a Lewis acid to give the β-isomer ( 16), which after deblocking with methanolic ammonia should give β-L-3'-deoxyerythro-pentofuranosyl nucleoside. An identical compound can also be prepared by reacting the corresponding 1-chloro derivative (15) with the sodium salt of a heterocyclic base, as in the case of 2'-deoxy L-nucleoside as shown in Scheme 6.

[image]

Scheme 7

Scheme 8: Preparation of L-2',3'-dideoxyribofuranosyl nucleoside (R1, R2, R3, R4, R5, R7 and R8 are hydrogen; R6 is hydroxyl): β-anomers of 2',3'-dideoxyribofuranosyl L-nucleoside of the formula (I-III) can be prepared by treating the corresponding 5'-O-triphenylmethyl-2',3'-bis(methanesulfonate)-β-L-ribofuranosyl nucleoside (17) with sodium hydrogen telluride (Clive, D. L., et al, J. Org: Chem., 61, 7426-7437, 1996) in CH3CN at room temperature as shown below. Finally, the trityl group can be removed from (18) under mild conditions to give 2',3'-dideoxy-ribofuranosyl β-L-nucleoside.

[image]

Scheme 8

Furthermore, substituted carbohydrates such as 1-bromo-2-deoxy-2-fluoro-3,6-O-benzoyl-L-arabinofuranose are known (Ma, T., et al, J. Med Chem., 39, 2835-2843 , 1996) and other modified L-configuration carbohydrates in the U.S. Pat. But. 5,473,063; WO 96/13512; WO 96/13498; WO 96/22778; WO 95/20595; LOUSE. 5,473,063; LOUSE. 5,567,688; Walczak, K., et al, Monatsh. fur Chemie, 123, 349-354 (1992); Wengel, J., et al., J. Org. Chem., 56, 3591-3594 (1991); Genu-Dellac, C., et al, Tetrahedron Letts., 32, 79-82(1991) and Czernecki, S., et al, Synthesis, 783(1991). Furthermore, the preparation of modified D-configuration carbohydrates and nucleosides in U.S. Pat. Pat. But. 5,192,749; WO 94/22890; Uteza, V., et al, Tetrahedron, 49, 8579-8588 (1993); Thrane, H., et al, Tetrahedron, 51, 10389-10403(1995); Yoshimura, Y., et al, Nucleosides & Nucleotides, 14, 427-429 (1993; Lawrence, A. J., et al, J. Org. Chem., 61, 9213-9222(1996); Ichikawa, S., et al. , J. Org. Chem., 62, 1368-1375(1997); EP 0 457 326 A1; U.S. Pat. No. 3,910,885; WO 96/13498 and Karpeisky, M,Y., et al, Nucleic Acids Res Symposium. Series, 9, I 57 (1981) By applying the synthetic procedures (schemes) described in these papers for the preparation of D-nucleosides, modified L-nucleosides can also be obtained.

Other compounds within the scope of this invention may be synthesized using the guidance provided in the individual schemes, as well as the specific examples and other schemes provided below. In addition to the guidance provided herein, those skilled in the art will know how to prepare compounds within the scope of this invention using the well-known techniques described in Nucleic Acid Chemistry, Improved and New Synthetic Procedures, Methods and Techniques, Published by Leroy B. Townsend and R Stuart Tipson, John Wiley & Sons, New York (1978-1991); Chemistry of Nucleosides and Nucleotides, by Leroy B. Townsend, New York, Plenum Press (1988-1994) and Nucleosides and Nucleotides as Antitumor and Antiviral Agents, by Chung K. Chu and David C. Baker, New York, Plenum Press (1993) ). Suitable methods for effecting substitution on the carbohydrate portion of the compounds claimed herein are known to those skilled in the art and are described in various publications, including:: U.S. Pat. Pat. But. 5,559,101; LOUSE. Pat. No. 5,192,749; LOUSE. Pat. No. 5,473,063; LOUSE. Pat. No. 5,565,438. Suitable methods for preparing various heterocyclic compounds and performing substitution thereon can be found in Chemistry of Nucleosides and Nucleotides, ed. Leroy B. Townsend, New York, Plenum Press, 2, 161-398 (1991) and Chemistry of Nucleosides & Nucleotides, ed. Leroy B. Townsend, New York, Plenum Press, 3, 1-53 S (1994).

Examples

This invention may be better explained by the following examples, given below, wherein compound numbers indicated in bold correspond to similarly marked numbers in Figures 1-12.

Example 1

1-O-methyl-2,3,5-tri-O-acetyl-β-L-ribofuranose (19)

L-ribose (15.0 g, 100 mmol) was dissolved in dry methanol (200 mL) and cooled to 0°C. A cold solution of H2SO4 (2 mL) was added with stirring and the reaction mixture was stirred at a temperature below 20°C for 12 h under an argon atmosphere. Dry pyridine (75 mL) was added and evaporated to dryness. Dry pyridine (100 mL) was added and evaporated under reduced pressure to an oily residue. These residues were dissolved in dry pyridine (150 mL) and treated with acetic anhydride (50 mL) at 0°C under argon. TEA (41 mL) was added, the reaction mixture was stirred at 0°C for 1 h at room temperature for 36 h, and evaporated to dryness. The residue was dissolved in water (200 mL), solid NaHCO3 was added to adjust the pH of the solution to 7. The aqueous mixture was extracted into CH2Cl2 (250 mL), washed with water (150 mL) and brine (100 mL), dried and concentrated. . The oily residue was filtered through a pad of silica gel (200 g), washed with CH2Cl2:EtOAc (8:2, 1000 mL). The filtrate was evaporated and the oil as obtained was used for the next reaction.

Example 2

1,2,3,5-tetra-O-acetyl-β-L-ribofuranose (2)

Syrup 19 (29.0 g, 100 mmol) from the above reaction was co-evaporated with dry toluene (2x100 mL) and dried overnight over solid NaOH at room temperature under vacuum. The dried syrup was dissolved in glacial acetic acid (150 mL) and cooled to 0°C under an argon atmosphere. To this cold solution was added acetic anhydride (35 mL) followed by H 2 SO 4 (10 mL) very slowly over 15 min. The reaction mixture was stirred at room temperature overnight and placed in ice (200 g) with stirring. This mixture was extracted with CHCl3 (2×200 mL) and the organic extract was washed with water (200 mL), saturated NaHCO3 (200 mL) and brine (150 mL), dried over anhydrous Na2SO4 and evaporated to dryness. 30 g (94%) of syrup was obtained, which was found to be sufficiently pure for the glycosylation procedure.

Example 3

Methyl 1-(2,3,5-tri-O-acetyl-β-L-ribofuranosyl)-1,2,4-triazole-3-carboxylate (20)

Mixture of methyl 1,2,4-triazole-3-carboxylate (0.64 g, 5 mmol), 1,2,3,5-tetra-O-acetyl-β-L-ribofuranose (2) (1.5 g, 4.72 mmol) and bis(p-nitrophenyl)-phosphate (20 mg) was placed in a pear-shaped flask and placed in a preheated oil bath at (160-165°C). The flask was connected to a water pump and kept at 160-165 °C (oil bath) under reduced pressure with stirring for 25 min. The reaction mixture was removed, cooled and diluted with EtOAc (150 mL) and saturated NaHCO3 solution (100 mL). The product was extracted into EtOAc. The organic extract was washed with water (100 mL) and brine (50 mL), dried and evaporated to dryness. The thus obtained residues were purified by "flash" chromatography on a silica-gel column using CHCl3 → EtOAc as eluent. The pure fractions were collected and evaporated to dryness to give 1.2 g (66%) of pure product:

1H NMR (CDCl3): δ 2.10 (3s, 9H, 3COCH3), 3.98 (s, 3H, OCH3), 4.22 (m, 1H), 4.46 (m, 2H), 5.54 (t, 1H), 5.76 ( m, 1H), 6.04 (d, 1H, C1.H) and 8.38 (s, 1H, C6H).

Analysis - calculated for C15H19N3O9 (385.22): C, 46.75; H, 4.97; N, 10.91. Found: C, 46.82; H, 4.57; N=10.71.

Example 3

1-β-L-ribofuranosyl-1,2,4-triazole-3-carboxamide (21)

Substrate (20) (1.1 g) was dissolved in CH3OH/NH3 at 0°C and placed in a steel autoclave. The autoclave was closed and the contents were stirred at room temperature for 18 h. The steel autoclave is cooled, opened and evaporated to dryness. Recrystallization with a little ethanol was attempted. The product crystallized, but after filtration the crystals reabsorbed water and became a paste. Crystallization was repeated several times. Finally, it crystallized from a methanol/ethanol mixture. The colorless crystals were filtered off, washed with methanol and dried under vacuum. The filtrate was evaporated again and after standing, new crystals formed. The total yield was 0.5 g (72%); mp: 177-179°C; [α]D = +38.33 (c 3 mg/mL H2O); D form of ribavirin [α]o = -36.0 (c 3.0 mg/mL H2O).

1H NMR (Me2SO-d6): δ 3.46 (m, 1H, C5H), 3.60 (m, 1H, C5.H), 3.92 (q, 1H, C4.H), 4.12 (q, 1H), 4.34 (q , 1H), 4.88 (t, 1H, C5.OH), 5.20 (d, 1H), 5.58 (d, 1H), 5.80 (d, 1H, C1.H), 7.60 (bs, 1H, NH), 7.82 (bs, 1H, NH) and 8.82 (s, 1H, C6H).

Analysis - calculated for C8H12N4O5 (244.20): C, 39.34; H, 4.95; N, 22.94. Found: C, 39.23; H, 4.97; N, 22.91.

Example 4

2,3-O-isopropylidene-L-ribose (22)

With stirring, iodine (1.27 g, 10 mmol) was added to a solution of L-ribose (30.0 g, 260 mmol) in dry acetone (200 mL) at room temperature under an argon atmosphere. The reaction mixture was stirred for 1 h (the solution was homogenized during this time) and quenched with sodium thiosulfate solution (1 M). The solution was evaporated to dryness.

The residue was dissolved in CH2Cl2 (250 mL), dried over anhydrous MgSO4, filtered and the solid washed with CH2Cl2 (150 mL). The combined filtrate was evaporated to dryness. The residues were placed on top of a silica-gel column (8×116 cm) packed in CHCl3. The column was eluted with CHCl3 (500 mL), CHCl3:EtOAc (9:1, 1000 mL) and CHCl3:EtOAc (7.3, 1500 mL). The pure product eluted with CHCl 3 : EtOAc (7:3) was collected and evaporated to give an oily residue 34.5 g (90%). The oily product was used as such for the next reaction.

1H NMR (CDCl3): δ 1.30 and 1.38 (2s, 6H, isopropylidene CH3), 3.70 (m, 3H), 4.08 (m, 1H), 4.08 (m, 1H), 4.55 (d, 1H), 4.81 (d , 1H) and 5.38 (m, 1H).

Example 5

1-deoxy-1-hydrazinyl-2,3-O-isopropylidene-L-ribose (23)

A solution of 2,3-O-isopropylidene-L-ribose 22 (34.5 g, 182 mmol) in absolute methanol (200 mL) was treated with a solution of anhydrous hydrazine (42.0 g, 1313 mmol) in absolute methanol (100 mL) dropwise over 30 min at room temperature in an argon atmosphere. The almost colorless solution was stirred at room temperature under anhydrous conditions for 18 h. The solution was evaporated in vacuo to give a colorless syrup. The syrup was co-evaporated with absolute methanol (5×100 mL). The resulting syrup was instantly heated (70°C) under vacuum pump pressure (0.1 torr) and kept under this pressure to dry for 12 h. The yield was 35.0 g (95%). This substance was used in this form for the next step without further purification.

Example 6

5-amino-4-cyano-1-(2',3'-O-isopropylidene-β-L-ribofuranosyl)pyrazole (24)

A solution of 1-deoxy-1-hydrazinyl-2,3-O-isopropylidene-L-ribose (23) (16.3 g, 79.90 mmol) in absolute ethanol (100 mL) was washed under a steady stream of argon for 30 min. A similarly washed solution of (ethoxymethylene)-malanonitrile (10.37g, 85 mmol) in absolute ethanol (100 mL) was added dropwise with vigorous stirring to the solution at room temperature for 1 h. The solution was stirred under argon for a further 30 min and then heated under reflux for 12 h. The orange solution was cooled to room temperature and evaporated in vacuo to dryness. This substance was dissolved in ethyl acetate (100 mL) and then treated with silica gel (50 g). The mixture was evaporated to dryness in vacuo and the resulting powder was loaded onto the top of a silica gel column (500 g) (6×30 cm, dry packed). The column was eluted with a solvent gradient of CH2Cl2 → EtOAc. Fractions containing the pure product were combined and evaporated to foam: yield 17 g (76%);

1H NMR(CDCl3): δ 1.30 and 1.52 (2s, 6H, isopropylidene CH3), 3.86 (m, 2H, C5.H), 4.40 (m, 1H, C4.H), 4.80 (bs, 2H, NH2), 5.00 (d, 1H), 5.20 (m, 1H), 5.80 (d, 1H, C1.H) and 7.54 (bs, 1H, C6H).

Analysis - calculated for C12H16N4O4 (280.28): C, 51.43; H, 5.75; N, 19.99. Found: C, 51.20; H, 5.63; N, 19.98.

Example 7

5-amino-1-(β-L-ribofuranosyl)pyrazole-4-carbonitrile (25)

A solution of 5-amino-1-(2',3'-O-isopropylidene-p-L-ribofuranosyl)-pyrazole-4-carbonitrile (24) (4.6 g, 16.43 mmol) in 90% trifluoroacetic acid (30 mL) was stirred at room temperature for 4 h. The reaction mixture was evaporated to dryness and the residue co-evaporated with methanol (3×35 mL). The residues as such were used for further reactions.

Example 8

5-amino-1-(β-L-ribofuranosyl)pyrazole-4-carboxamide (26)

30% hydrogen peroxide (2 mL) was added to a solution of (25) (4.60 g) in ammonium hydroxide (35 mL). The solution was stirred in a pressure vessel at room temperature for 18 h, the pressure vessel was cooled, carefully opened and the volatile products were evaporated to dryness. The residues thus obtained were co-evaporated with ethanol (3×20 mL). The crude product, after crystallization from the ethanol/water mixture, gave the pure product 3.5 g (71%):

1H NMR (DMSO-d6): δ 3.57 (m, 2H, C5.CH2), 3.86 (q, 1H, C4.H), 4.11 (q, 1H, C3.H), 4.43 (q, 1H, C2. OH), 5.63 (d, 1H, J=3.99 Hz, C1.H), 6.51 (br s, 2H, NH2), 6.71 and 7.26 (2br s, 2H, CONH2) and 7.69 (s, 1H, C3H).

Analysis - calculated for C9H14N4O5 (258.23): C, 41.86; H, 5.46; N, 21.69. Found: C, 41.57; H, 5.40; N, 21.61.

Example 9

5-amino-1-(2',3'-O-isopropylidene-β-L-ribofuranosyl)pyrazole-3,4-dicarbonitrile (27)

A solution of tetracyanoethylene (24.32 g, 190 mmol) in absolute EtOH (100 mL) was added dropwise with stirring to a solution of 1-deoxy-1-hydrazinyl-2,3-O-isopropylidene-L-ribose (223.0 g, 1113.0 mmol) in EtOH. (100 mL), during 30 min at 0°C. The reaction mixture was stirred in an ice bath for a further 2 h and then stirred at room temperature for 15 h. The brown solution was filtered and evaporated to dryness. The residues were dissolved in MeOH (50 mL), adsorbed onto silica gel (90 g) and placed on top of a silica gel column (10×25 cm) packed with CH2Cl2. The column was eluted with CH2Cl2/EtOAc (10:1, v/v); homogeneous fractions were combined and evaporated to dryness. The remaining yellow foam was crystallized from ethanol after long standing to give 15 g (44%) of pure (27): m.p. °C.

1H NMR (Me2SO-d6): δ 1.31 and 1.48 (2s, 6H, isopropylidene-CH3), 3.29 (m, 2H, C5.CH2), 4.13 (m, 1H, C4.H), 4.83 (m, 1H, C3.H), 4.97 (t, 1H, C5.OH), 5.24 (m, 1H, C2.H), 6.12 (s, 1H, C1.H), 7.65 (s, 2H, NH2).

Analysis - calculated for C13H15N5O4 (305.29): C, 51.14; H, 4.95; N, 22.94. Found: C, 51.20; H, 5.04; N, 22.61.

Example 10

5-amino-1-β-L-ribofuranosylpyrazole-3,4-dicarbonitrile (28)

A suspension of 5-amino-1-(2',3'-O-isopropylidene-β-L-ribofuranosyl)-pyrazole-3,4-dicarbonitrile (4.6 g, 15.0 mmol) in 90% TFA/water (50 mL) was stirred is at room temperature for 12 h. The solvent was evaporated and the residues were co-evaporated with EtOH (3×50 mL). The thus obtained light brown residues were used for further reactions.

Example 11

5-amino-1-β-L-ribofuranosylpyrazole-3,4-dicarboxamide (29)

The TFA salt of 5-amino-1-β-L-ribofuranosylpyrazole-3,4-dicarbonitrile (28) (2.60 g, 10.0 mmol) was dissolved in conc. NH4OH (28%, 100 mL) and treated with H2O2 (30%, 15 mL). The reaction mixture was stirred at room temperature in a pressure vessel for 12 h and then evaporated to dryness. The residues were combined with (3×50 mL).

The crude product was crystallized from EtOH/water to give 2.0 g (68%) (29): m.p. x °C.

1H NMR(Me2SO-d6): δ 3.60 (m, 2H, C5.CH2), 3.87 (m, 1H, C4.H), 4.18 (m, 1H, C3.H), 4.54 (m, 1H, C2. H), 4.91 (t, 1H, C5.OH), 5.03 and 5.38 (2d, 2H, C2.,3.OH), 5.69 (d, 1H, C1.H), 6.99 (br s, 3H, NH2 and CONH(H)), 7.72 and 7.78 (2s, 2H, CONH2). 9.65 (d, 1H, CON(H)H).

Analysis - calculated for C10H15N5O6 (301.26): C, 39.87; H, 5.03; N, 23.25. Found: C, 39. 72; H, 5.40; N, 23.61.

Example 12

Dimethyl 1,2,3-triazole-4,5-dicarboxylate (30)

With stirring, to a solution of sodium azide (5.03 g, 77.39 mmol) in DMF (120 mL) was added dropwise at 0°C over 30 min a solution of dimethyl acetylene dicarboxylate (10.0 g, 70.36 mmol) in DMF (100 mL). After 30 min the solvent was removed in vacuo at 30°C to give a light purple-brown solid. The solid was washed twice with ether and dissolved in water (100 mL). The aqueous solution was acidified with conc. HCl to pH 2. The aqueous layer was extracted first with ether (100 mL) and then with chloroform (100 mL). The combined organic layers were evaporated to give a light red colored solid: 128-130 °C. The solid was washed with hot hexane and crystallized from benzene: yield 11.0 g (85%).

1H NMR (CDCl3): δ 4.00 (s, 6H), 11.87 (br s, 1H, NH).

Example 13

1-O-acetyl-2,3,5-tri-O-benzoyl-β-L-ribofuranose (5)

To a solution of L-ribose (25.0 g, 166.66 mmol) in MeOH (300 mL) was added 25 mL of saturated methanolic hydrogen chloride solution and stirred at room temperature for 6 h. The reaction was complete after 6 h as indicated by TLC using CH 2 Cl 2 /MeOH 9:1. After completion of the reaction, dry pyridine (30 mL) was added and the solvent was evaporated. A further 30 mL of pyridine was added to the residue and evaporated to dryness. The residues were dissolved in dry pyridine (200 mL) and CH2Cl2 (150 mL) and cooled to 0°C. Benzoyl chloride (96.26 mL, 830.12 mmol) was added dropwise and stirred at room temperature overnight. TLC using hexane/ethyl acetate (7:3) indicated completion of the reaction. The solvent was evaporated and the residue was dissolved in CHCl3 (300 mL) and washed with H2O (200 mL) and saturated NaHCO3 (200 mL), and dried over anhydrous Na2SO4. After evaporation in CHCl 3 , the residue was co-evaporated with toluene to give an oily residue. The residue was dissolved in AcOH (200 mL), acetic anhydride (85.0 mL; 770.9 mmol) and sulfuric acid (4.46 mL; 83.29 mmol). The reaction mixture was stirred at room temperature overnight, after which TLC (hexane/ethyl acetate 7:3) showed completion of the reaction. The solvents were evaporated in vacuo and the resulting residues were co-evaporated with toluene. The brown residue was triturated with EtOH to give brown crystals. Filtration of the solid and recrystallization from EtOH gave 1-O-acetyl-2,3,5-tri-O-benzoyl-L(+)-glucofuranose 40.5 g (48.0%) as white crystals: m.p. 125-125 °C.

1H NMR (CDCl3): δ 4.49 (m, 1H, C5.H), 4.77 (m, 2H, C4.H and C5.H), 5.80 (d, 1H), 5.93 (m, 1H, C2.H) , 6.43 (d, 1H, C1.H, J1,2=1.5 Hz) and 7.30-8.09 (m, 15H, PhH).

Example 14

Dimethyl 2-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)-1,2,3-triazole-4,5-dicarboxylate (31)

A mixture of dry dimethyl 1,2,3-triazole-4,5-dicarboxylate (3.70 g, 20.0 mmol), hexamethyldisilazane (HMDS, 60 mL) and (NH4)2SO4 (0.1 g) was heated under reflux (oil bath temperature 140° C) during 12 h with exclusion of moisture. Excess HMDS was removed by vacuum distillation to give the trimethylsilyl derivative, which was dissolved in anhydrous CH 3 CN (100 mL).

To the above clear solution was added 1-O-acetyl 2,3,5 tri-O-benzoyl-L-ribofuranose (10.12 g, 20 mmol) and the mixture was stirred for 10 min. With stirring, trimethylsilyl trifluoromethanesulfonate (4.6 mL, 26.0 mmol) was added to the solution and stirring was continued for 12 h at ambient temperature. The reaction mixture was evaporated and the residue was dissolved in CH2Cl2 (500 mL). The organic layers were successively washed with saturated aqueous NaHCO3 solution (3×100 mL), saturated NaCl solution (3×100 mL) and water (3×50 mL) and dried over anhydrous Na2SO4. The solvent was evaporated to give 12.0 g (95%) on 31

1H NMR (Me2SO-d6): δ 3.88 (s, 6H, 2 OCH3), 4.65 (m, 2H, C5.H), 5.01 (m, 1H, C4.H), 6.10 (m, 1H, C3.H ), 6.32 (m, 1H, C2.H), 6.88 (d, 1H, C1.H, J1,2=2.75 Hz) and 7.45-7.95 (m, 15H, PhH).

Example 15

2-β-L-ribofuranosyl-1,2,3-triazole-4,5-dicarboxamide (32)

Compound 31 (6.0 g, 9.5 mmol) was dissolved in MeOH/NH3 (dry MeOH saturated with anhydrous NH3 at 0°C, 60 mL) and placed in a steel reaction vessel. The vessel was heated to 95°C for 16 h. The reaction vessel was cooled, carefully opened and the NH3 evaporated at room temperature. The MeOH was evaporated to dryness and the residue was triturated with hot toluene (3×50 mL) and filtered. The brown residue was crystallized from aqueous EtOH (95%) to give 2.40 g (89%) of 32: m.p. 210-212 °C.

1H NMR (Me2SO-d6): δ 3.45-3.59 (m, 2H, C5.H), 3.98 (m, 1H, C4.H), 4.25 (m, 1H, C3.H), 4.54 (m, 1H, C2.H), 4.78 (t, 1H, C5.OH, D2O exchangeable), 5.27 and 5.67 (2d, 2H, C2.,3.OH, D2O exchangeable), 5.89 (d, 1H, J1.,2. = 3.85 Hz, C1.H), 8.05 and 9.05 (2br s, 4H, 2 CONH2).

Analysis - calculated for C9H13N5O6 (287.23): C, 37.63; H, 4.56; N, 24.38. Found: C, 37.52; H, 4.19; N, 24.59.

Example 16

1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)pyridin-4-one-3-carboxamide (33)

To a mixture of hexamethyldisilazane (50 mL, 239.77 mmol) and chlorotrimethylsilane (1.0 mL, 21.43 mmol) was added pyridin-4-one-3-carboxamide (1.38 g, 10.0 mmol) (Prepared by a procedure described in: W. C. J. Ross, J. Chem. . Soc., C, 1816, (1966); W. Herz and D. R. K. Murty, J. Org. Chem., 26, 122, 1961). The mixture was refluxed with stirring for 2 h and evaporated to dryness under vacuum and then dried under high vacuum for 2 h at 60°C. The dry gummy residue was suspended in freshly distilled 1,2-dichloroethane (50 mL) and 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose (5.06 g, 10.0 mmol) was added to the suspension and freshly distilled SnCl4 (1.0 mL, 8.52 mmol). The reaction mixture was refluxed for 1.5 h, cooled and diluted with CH2Cl2 (100 mL) and saturated NaHCO3 solution (25 mL). The mixture was filtered through a celite pad which was washed with CH2Cl2 (20 mL). The organic phase was separated, washed with water until the eluates were neutral, and dried over anhydrous sodium sulfate. The organic extract was evaporated to dryness to give a gummy residue. The residues were purified by "flash" chromatography on silica gel using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and concentrated to give 0.50 g (9%) of 33 as a white foam:

1H NMR (CDCl3): δ 4.94 (m, 3H, C4·H and C5.H), 6.12 (m, 1H), 6.20 (m, 1H), 6.32 (d, 1H) and 7.20-8.30 (m, 20H ).

Example 17

1-β-L-ribofuranosylpyridin-4-one-3-carboxamide (34)

Compound 33 (0.5 g, 0.86 mmol) was dissolved in dry methanolic ammonia (50 mL) and stirred for 15 h in an autoclave at room temperature. The solution was then concentrated to a small volume and cooled overnight at 4°C. The resulting crystalline product was filtered off and washed with cold methanol. The solid was recrystallized from absolute ethanol to give 0.23 g (87%) of pure product: m.p. 209-211°C.

1H NMR (Me2SO-d6): δ 3.60 (m, 2H, C5.H), 3.93 (m, 1H, C4.H), 4.09 (m, 1H, C3.H), 4.34 (m, 1H, C2. H), 5.11 (m, 1H, C5.OH, D2O exchangeable), 5.22 and 5.47 (2m, 2H, C2.,3.OH, D2O exchangeable), 5.84 (d, 1H, J1.,2.= 6.3 Hz , C1.H), 7.21 (m, 2H, PhH), 7.64 (m, 2H, PhH and CONH2) and 8.44 (s, 1H, CONH2).

Analysis - calculated for C11H14N2O6 (270.24): C, 48.89; H, 5.22; N, 10.37. Found: C, 48.89; H, 5.42; N, 10.51.

Example 18

2,3,5-tri-O-benzoyl-β-L-ribofuranosyl azide (35)

Dry hydrogen chloride was passed through a suspension of finely atomized and dried 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribose (20.0 g, 39.52 mmol) in ether (300 mL) at 0°C until no clear solution was obtained (2-3 h). The mixture was left at 0°C overnight. The solvent was removed and the remaining gum was evaporated sequentially first with dry benzene (2×25 mL) and with toluene (25 mL). The residues were dissolved in methyl cyanide (250 mL). To this was added sodium azide (20.0 g, 307.6 mmol) and the reaction mixture was refluxed under an argon atmosphere for 2 h. After completion of the reaction, as determined by TLC hexane/ethyl acetate (7:3), the solution was filtered and evaporated to give an oily product (14.6 g) in quantitative yield. The product gave a white foam when dried under high vacuum. The dried substance was used as such for further reactions.

1H NMR (CDCl3): δ 4.54 (m, 1H), 4.76 (m, 2H), 5.57-5.58 (dd, 1H), 5.68 (d, 1H, J=1.65 Hz), 5.84-5.86 (m, 1H) and 7.34-8.12 (m, 15H, PhH).

Example 19

5-amino-1-(2',3',5'-tri-O-acetyl-β-L-ribofuranosyl)triazole-4-carboxamide (36)

N,N-Dimethylformamide (60 mL) was added to a cold (0°C) solution of potassium hydroxide (1.72 g, 30.7 mmol) in water (10 mL) and the solution was stirred at this temperature for 10 min. Cyanoacetamide (2.58 g, 30.68 mmol) was added to this solution and the mixture was then stirred at 0 °C until the solid dissolved. To this solution was added 2,3,5-tri-O-benzoyl-β-L-ribofuranosyl azide (10.0 g, 20.5 mmol) in one portion, and the reaction mixture was stirred at -5°C for 14 h. The amber solution was evaporated in vacuo (water bath 50°C) to give an orange semi-solid, which was evaporated sequentially first with absolute ethanol (2×50 mL) and toluene (3×50 mL) in vacuo to give a thick orange gum. . The gum was dissolved in anhydrous methanol (150 mL), sodium methoxide (1 N, 25 mL) was added and the solution was stirred at room temperature under anhydrous conditions for 6 h. The amber solution was treated with Dowex 50 X H+ ion exchange resin (ca. 35 mL of wet resin) to adjust the pH to 6. The solution was filtered, the resin was washed with additional methanol (50 mL), and the combined filtrates were evaporated to dryness in vacuum (water bath at 80°C) to give an orange gum. The gum was repeatedly slurried with ethyl acetate (6×50 mL), and each portion was decanted again until the gum solidified into a brown amorphous solid. Off-white product 2.5 g (32%) was chromatographically pure. After several crystallizations, the impurity-containing product was converted to the acetate form as described below.

The above crude taurine (0.4 g, 1.54 mmol) was dissolved in dry pyridine (10 mL). The solution was cooled to 0°C in an argon atmosphere and treated with acetic anhydride (0.95 g, 9.26 mmol). The reaction mixture was stirred at room temperature overnight and quenched with methanol (1.0 mL). The solvent was removed and the residue was dissolved in CH2Cl2 (100 mL). The organic layer was washed with saturated NaHCO3 solution (100 mL) and brine (50 mL), dried and evaporated to dryness. The crude product was purified by flash chromatography on silica gel using EtOAc as eluent: Yield 0.52 g (88%);

1H NMR (CDCl3): δ 2.12 (3s, 9H, 3 COCH3), 4.32-4.52 (m, 3H), 5.64 (m, 1H, C3.H), 5.85 (m, 1H, C2.H), 6.00 ( br s, 2H, NH2), 6.32 (d, 1H, C1.H) and 8.73 (br s, 2H, CONH2).

Example 20

5-amino-1-β-L(+)-ribofuranosyltriazole-4-carboxamide (37)

Compound 36 (0.5 g, 1.29 mmol) was dissolved in methanolic ammonia (50 mL, saturated at °C). The reaction mixture was stirred at room temperature for 16 h and evaporated to dryness. The residue was triturated three times with EtOAc and the solid was crystallized from a minimal amount of dry EtOH to give a colorless solid: m.p. 159-161°C.

1H NMR (Me2SO-d6): δ 3.40-3.52 (m, 2H, C5.H), 3.93 (m, 1H, C4.H), 4.19 (m, 1H, C3.H), 4.46 (m, 1H, C2.H), 4.74, 5.22, 5.62 (m, 3H, 3 OH, D2O exchangeable), 5.84 (d, 1H, J=3.90 Hz, C1.H), 7.95 (br s, 2H) and 9.02 (br s , 2H).

Analysis - calculated for C8H13N5O5 (259.22): C, 37.07; H, 5.05; N, 27.02. Found: C, 37.36; H, 5.14; N, 27.01.

Example 21

5-O-acetyl-1-(2',3',5'-tri-O-acetyl-β-L-ribofuranosyl)triazole-4-carboxamide (38)

N,N-dimethylformamide (40 mL) was added to a cold (0°C) solution of potassium hydroxide (1.16 g, 20.82 mmol) in water (20 mL), and the solution was stirred at this temperature for 10 min. Ethyl malonamate (2.73 g, 20.82 mmol) was added to this solution and the mixture was then stirred at 0°C until the solid dissolved. To this solution was added 2,3,5-tri-O-benzoyl-β-L-ribofuranosyl azide (6.76 g, 13.88 mmol) in one portion and the reaction mixture was stirred at -5°C for 14 h. The amber solution was evaporated in vacuo (water bath at 80°C to give an orange semi-solid, which was co-evaporated sequentially with absolute ethanol (2×50 mL) and toluene (3×50 mL) in vacuo to give a thick orange gum .

The gum was dissolved in anhydrous methanol (150 mL), sodium methoxide (0.5 N, 10 mL) was added and the solution was stirred at room temperature under anhydrous conditions for 6 h. The amber solution was treated with Dowex 50 X H+ ion exchange resin (ca. 35 mL of wet resin) to adjust the pH to 6. The solution was filtered, the resin layer was washed with an additional 50 mL of methanol, the combined filtrates were evaporated to dryness in vacuum (water bath 80°C) to give an orange gum. The gum was successively slurried with ethyl acetate (6×50 mL), and each portion was decanted again until the gum solidified into a brown amorphous solid. The solid was suspended in anhydrous pyridine (30 mL) and acetic anhydride (7.8 mL, 83.28 mmol), and stirred at room temperature for 18 h. The reaction mixture was filtered through a layer of packed celite. The celite layer was washed with fresh pyridine (50 mL) and the combined filtrates were evaporated to dryness in vacuo to afford a brown gum. The gum was dissolved in CH2Cl2 (150 mL). The organic layer was washed with saturated NaHCO3 solution (100 mL) and brine (50 mL), dried and evaporated to dryness. The crude product was purified by flash chromatography on silica gel using CH2Cl2 → EtOAc as eluent. Pure fractions were collected and evaporated to give 1.5 g (42%) of pure product 38.

1H NMR (CDCl3): δ 2.14 (3s, 9H, 3 COCH3), 2.60 (s, 3H, COCH3), 4.15-4.58 (m, 3H, C4.H and C5.H), 5.62 (m, 1H, C3 .H), 5.82 (m, 1H, C2.H), 6.28 (d, 1H, C1.H) and 10.63 (br s, 2H, CONH2).

Example 22

5-hydroxy-1-β-L(+)-ribofuranosyltriazole-4-carboxamide (39)

Compound 38 (1.5 g, 3.50 mmol) was dissolved in methanolic ammonia (50 mL, saturated at °C). The reaction mixture was stirred at room temperature for 16 h and evaporated to dryness. The residue was triturated three times with EtOAc and the solid crystallized from a minimal amount of dry EtOH to give 0.70 g (77%) of 39: m.p. 162-164 °C.

1H NMR (Me2SO-d6): δ 3.40 - 3.50 (m, 2H, C5.H), 3.84 (m, 1H, C4.H), 4.17 (m, 1H, C3.H), 4.32 (m, 1H, C2.H), 4.90 (t, 1H, C5.OH), 5.20, 5.58 (2d, 2H, 2OH, D2O exchangeable), 5.76 (d, 1H, J=3.90 Hz, C1.H), 7.58 and 7.80 (2 no s, 2H, CONH2) and 8.82 (s, 1H, C5OH).

Analysis - calculated for C8H12N4O6 (260.21): C, 36.92; H, 4.65; N, 21.53. Found: C, 36.90; H, 4.79; N, 21.43.

Example 23

1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)-6-methyluracil (40)

A mixture of 6-methyluracil (2.52 g, 20.0 mmol), hexamethyldisilazine (50 mL) and ammonium sulfate (100 mg) was refluxed at 135°C for 6 h. The solvent was removed in vacuo and the resulting residue was co-evaporated with dry toluene (2×50 mL) to remove the last traces of hexamethyldisilazine. The thus obtained solid was dried under vacuum for 6 h. A solution of 2,4-bis(trimethylsilyloxy)-6-methylpyrimidine (20.0 mmol) in dry acetonitrile (100 mL) and 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose (10.12 g, 20 mmol) and trimethylsilyl triflate (5.78 g, 26.0 mmol). The reaction mixture was stirred under argon at room temperature for 16 h. The reaction mixture was concentrated in vacuo and the residue was dissolved in dichloromethane (200 mL). The organic layer was washed with saturated sodium bicarbonate solution (200 mL) and brine (100 mL), dried over sodium sulfate, and concentrated to give a white foam. Further separation of the crude product by flash chromatography on silica gel using CH2Cl2 → EtOAc gave two products. The yield of the second fraction was 4.50 g (42%).

1H NMR (CDCl3): δ 2.28 (s, 3H, CH3), 4.65-4.81 (m, 3H, C4.H and C5.H), 5.60 (m, 1H, C3.H), 5.72 (s, 1H) , 6.11 (m, 1H), 7.24-8.06 (m, 16H, PhH) and 9.40 (br s, 1H, NH). The first fraction (4.20 g) does not correspond to the desired compound according to 1H NMR.

Example 24

1-β-L-ribofuranosyl-6-methyluracil (41)

Solution 40 (4.50 g, 7.86 mmol) was dissolved in saturated methanolic ammonia (60 mL). The reaction mixture was heated to 100°C for 17 h in a steel autoclave. The reaction vessel was cooled to room temperature to obtain an oil. The residues were further purified by flash chromatography using dichloromethane and methanol (9:1) as eluent. The pure fractions were collected and evaporated to give a white solid. Recrystallization from 2-propanol was then carried out to give 1.98 g (94%) of pure 41: m.p. 175-77 °C.

1H NMR (Me2SO-d6): δ 2.24 (s, 3H, CH3), 3.42-3.57 (m, 2H, C5.H), 3.68 (m, 1H, C4.H), 4.0 (m, 1H, C3. H), 4.53 (m, 1H, C2.H), 4.68, 4.94, 5.22 (m, 3H, 3 OH, D2O exchangeable), 5.43 (d, 1H, C1.H, J1.,2. = 3.85 Hz) , 5.56 (s, 1H, C5H) and 11.25 (s, 1H, NH).

Analysis - calculated for C10H14N2O6 (258.23): C, 46.51; H, 5.46; N, 10.85. Found: C, 46.66; H, 5.26; N, 10.66.

Example 25

1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)-5-azacytidine (42)

5-azacytosine (1.12 g, 10.0 mmol) was suspended in a mixture of hexamethyldisilazine (50 mL) and ammonium sulfate (100 mg). The reaction mixture was refluxed at 135°C for 6 h. Later, the solvent was removed in vacuo and the resulting residue was co-evaporated twice with dry toluene (2×50 mL) to remove the last traces of hexamethyldisilazine. The thus obtained solid was dried in vacuum for 6 h. 1-O-acetyl-2,3,5-tri-O-benzoyl was added to a solution of 2,4-N,bis(trimethylsilyl)-5-azacytidine (10.0 mmol) in dry 1,2-dichloroethane (150 mt.) -β-L-ribofuranose (5.06 g, 10 mmol) and stannous chloride (1.68 mL, 14.16 mmol) at 10°C. The reaction mixture was stirred in an argon atmosphere at 10°C for 2 h. The reaction was checked by TLC using hexane and ethyl acetate (7:3). TLC showed no starting material. The reaction mixture was diluted with dichloromethane (250 mL). The organic layer was washed with saturated sodium bicarbonate solution (200 mL) and brine (100 mL), dried over sodium sulfate and concentrated to a residue. The residues were dissolved in toluene and filtered through celite to remove unreacted 5-azacytosine. The filtrate was evaporated to dryness and the residue (5.20 g) was dissolved in ethanol and filtered again through celite. The title compound was crystallized from the filtrate as needles 4.45 g (81%): m.p. 186-187 °C.

1H NMR (CDCl3): δ 4.62-4.66 (m, 3H, C4.H and C5.H), 6.01 (m, 3H, C1.H, C2.H and C3.H), 7.26-8.06 (m, 17H , NH2 and PhH) and 8.48 (s, 1H, C6H).

Example 26

4-amino-1-β-L-ribofuranosyltriazin-2(1H)-one (5-azacytidine, 43)

Compound 42 (4.0 g, 7.19 mmol) was dissolved in absolute methanol (60 mL), heated to boiling and treated with 0.5 M sodium methoxide (20 mL, 10.0 mmol). The starting substance is quickly dissolved and the solution is a settled product from the solution. The mixture was kept at room temperature for 4 hours and overnight. The crystals were collected, washed with ice-cold methanol (10 mL) and dried under reduced pressure at room temperature. Yield 1.50 g (86%). The analytical sample was obtained after recrystallization from a water-acetone mixture (1:1): m.p. 220-222 °C.

1H NMR (D2O): δ 3.78-3.97 (m, 2H, C5.H), 4.13 (m, 1H, C4.H), 4.20 (m, 1H, C3.H), 4.33 (m, 1H, C2. H), 6.31 (d, 1H, C1.H, J1.,2. = 2.5 Hz) and 8.24 (s, 1H, C6H).

Analysis - calculated for C8H12N4O5 (244.20): C, 39.35; H, 4.95; N, 22.94. Found: C, 34.09; H, 4.28; N, 22.98.

Example 27

1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)-6-azauridine (44)

6-azauracil (1.36 g, 12.0 mmol) was suspended in a mixture of hexamethyldisilazine (50 mL) and ammonium sulfate (50 mg). The reaction mixture was refluxed at 135°C for 6 h. Later, the solvents were removed in vacuo and the resulting residue was co-evaporated twice with dry toluene (2×50 mL) to remove the last traces of hexamethyldisilazine. The solid was dried in vacuo for 6 h and used in the next step of the synthesis without further purification. To a solution of 2,4-bis(trimethylsilyl)-6-azauridine (12.0 mmol) in dry 1,2-dichloroethane (60 mL) was added 1-O-acetyl-2,3,5-tri-O-benzoyl-L- ribofuranose (5.06 g, 10 mmol) and stannous chloride (1.68 mL, 14.16 mmol) at 10°C. The reaction mixture was stirred under an argon atmosphere at room temperature for 6 h. The reaction was checked by TLC using hexane and ethyl acetate (7:3). TLC showed no starting material. The reaction mixture was diluted with dichloromethane (250 mL). The organic layer was washed with cold saturated sodium bicarbonate solution (150 mL) and brine (100 mL), dried over sodium sulfate, and concentrated to a white foam. The residue was dissolved in dichloromethane (100 mL) and filtered through celite to remove unreacted 6-azauracil. The filtrate was evaporated to a residue (4.50 g), dissolved in a minimal amount of ethanol and filtered through celite. The title compound was crystallized from the filtrate as needles to give 4.50 g (79%) of pure 44: m.p. 193-195 °C.

1H NMR (Me2SO-d6): δ 4.47-4.67 (m, 3H, C5.H), 4.71 (m, 1H, C4.H), 5.85 (m, 1H, C3.H), 5.93 (m, 1H, C2.H), 6.38 (d, 1H, J1.,2. = 2.56 Hz, C1.H), 7.26-8.06 (m, 16H, C5H and PhH) and 12.32 (s, 1H, NH).

Example 28

1-β-L-ribofuranosyl-6-azauracil (6-azauridine 45)

Compound 44 (4.5 g, 7.95 mmol) was dissolved in absolute methanolic ammonia (6 mL) and placed in a steel autoclave. The solution was heated to 100°C for 16 h. Later, the reaction vessel was cooled to room temperature and the solvent was removed under vacuum. The thus obtained residues were slurried with hot toluene (2×50 mL). The residues were dissolved in 95% ethanol and left at room temperature. The white solid crystals thus obtained were collected by filtration and dried in vacuo. Yield 1.75 g (89%): m.p. 151-153 °C.

1H NMR (Me2SO-d6): δ 3.30-3.47 (m, 2H, C5.H), 3.73 (m, 1H, C4.H), 3.92 (m, 1H, C3.H), 4.17 (m, 1H, C2.H), 4.62, 4.98, 5.22 (3br s, 3H, 3 OH, D2O exchangeable), 5.82 (d, 1H, C1.H, J1.,2. = 3.85 Hz), 7.48 (s, 1H, C5H ) and 11.20 (br s, 1H, NH).

Analysis - calculated for C8H11N3O6 (245.19): C, 39.19; H, 4.52; N, 17.14. Found: C, 38.81; H, 4.58; N, 17.04.

Example 29

Diethyl imidazole-4,5-dicarboxylate (46)

Imidazole-4,5-dicarboxylic acid (7.55 g, 50.0 mmol) was dissolved in absolute ethyl alcohol (120 mL). The solution was cooled in an ice bath to 0°C and dry HCl gas was blown through for 1 h. Later, the reaction mixture was refluxed at 80°C for 7 h during which time the starting material was consumed. The solvent was removed and the thus obtained residues were dissolved in dichloromethane (200 mL) and the organic layer was neutralized with triethylamine. The organic layer was washed with cold water (100 mL) and brine (50 mL), dried over anhydrous sodium sulfate in vacuo to give 5.50 g (52%) of a white solid: m.p. 175-177 °C.

1H NMR (CDCl3): δ 1.40 (t, 3H), 4.41 (m, 2H), 7.84 (1H, C2H) and 11.55 (br s, 1H, NH).

Example 30

Diethyl 1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)imidazole-4,5-dicarboxylate (47)

A mixture of diethyl imidazole-4,5-dicarboxylate (2.65 g, 12.50 mmol) and ammonium sulfate (50 mg) was heated under reflux at 135°C for 6 h with hexamethyldisilazine (50 mL). The reaction mixture was evaporated to dryness and the residue was co-evaporated twice with dry toluene (2×50 mL) to remove traces of hexamethyldisilazine. The thus obtained solid was dried in vacuum for 6 h and used in the next step without further determination of properties. To a solution of the above residue (12.5 mmol) in 1,2-dichloroethane (60 mL) was added 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose (5.06 g, 10 mmol) and tin chloride (1.68 mL, 14.16 mmol) at 10°C. The reaction mixture was stirred under an argon atmosphere at room temperature for 6 h. The reaction mixture was checked by TLC using hexane and ethyl acetate (7:3). TLC showed that no starting material remained. The reaction mixture was diluted with dichloromethane (200 mL). The organic layer was washed with cold saturated sodium bicarbonate solution (200 mL) and brine (100 mL), dried over sodium sulfate and concentrated to give a white foam. The residue was dissolved in dichloromethane (100 mL) and filtered through celite to remove the tin salt. After evaporation in a vacuum, the residues (4.70 g) were dissolved in ethanol and filtered again through celite. The title compound 47 crystallized from the filtrate in the form of needles. Yield 4.70 g (72%): m.p. 134-136 °C.

1H NMR (CDCl3): δ 1.28 (t, 3H, CH3), 1.37 (t, 3H, CH3), 4.28-4.40 (m, 4H, 2 CH2), 4.65-4.88 (m, 3H, C4.H and C5 .H), 5.85 (m, 2H, C2.H and C3.H), 6.68 (d, 1H, C1.H, J1.,2. = 3.90 Hz) and 7.26-8.08 (m, 16H, C2H and PhH ).

Example 31

1-β-L-ribofuranosylimidazole-4,5-dicarboxamide (48)

Compound 47 (4.0 g, 6.09 mmol) was dissolved in absolute methanolic ammonia (60 mL) and heated at 100°C for 16 h in a steel autoclave. Later, the reaction mixture was cooled to room temperature. The product crystallized from methanol. The precipitated product was removed by filtration and the filtrate was then concentrated to give a second yield of product. The combined product was recrystallized once more from methanol to give 1.68 g (100%) of a white solid: m.p. 224-226°C.

1H NMR (Me2SO-d6): δ 3.53-3.75 (m, 2H, C5.H), 3.84 (m, 1H, C4.H), 3.96 (m, 2H, C2.H and C3.H), 4.97, 5.16, 5.36 (3br s, 3H, 3 OH, D2O exchangeable), 6.49 (d, 1H, C1.H, J1.,2. = 2.1 Hz), 7.60 (s, 1H, CONH2), 7.88 (s, 1H , CONH2), 7.99 (s, 1H, CONH2), 8.48 (s, 1H, C2H) and 10.59 (s, 1H, CONH2).

Analysis - calculated for C10H14N4O6 (286.24): C, 41.96; H, 4.93; N, 19.57. Found: C, 41.89; H, 5.05; N, 19.41.

Example 32

Ethyl 1-(2',3',5'-tri-O-benzoyl-β-L-ribofuranosyl)-3-hydroxy-1,2-pyrazole-4-carboxylate (49)

A mixture of ethyl 3-hydroxy-1,2-pyrazole-4-carboxylate (1.95 g, 12.50 mmol) and ammonium sulfate (50 mg) in hexamethyldisilazine (50 mL) was heated under reflux for 6 h. The reaction mixture was evaporated to dryness and the resulting residue was co-evaporated twice with dry toluene (2×50 mL) to remove the last traces of hexamethyldisilazine. The thus obtained solid was dried in vacuum for 6 h and used as such in further reactions. To a solution of the above-mentioned trimethylsilyl derivative (12.5 mmol) in dry 1,2-dichloroethane (60 mL) was added 1-O-acetyl 2,3,5-tri-O-benzoyl-L-ribofuranose (5.06 g, 10 mmol) and tin tetrachloride (1.68 mL, 14.16 mmol) at 10°C. The reaction mixture was stirred under an argon atmosphere at room temperature for 6 h. The reaction mixture was diluted with dichloromethane (200 mL). The organic layer was washed with saturated sodium bicarbonate solution (200 mL), water (100 mL) and brine (100 mL), dried over sodium sulfate and concentrated to foam. The residue was dissolved in dichloromethane (70 mL) and filtered through celite to remove the tin salt. The crude product was purified by flash column chromatography using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and evaporated to give 3.50 g (57%) of a white foam:

1H NMR (CDCl3): δ 1.36 (t, 3H, CH3), 4.30 (m, 2H, CH2), 4.52-4.82 (m, 3H, C4.H and C5.H), 6.08-6.32 (m, 3H, C1.H, C2.H and C3.H) and 7.26-8.08 (m, 16H, C5H and PhH).

Example 33

1-β-L-ribofuranosyl-3-hydroxy-1,2-pyrazole-4-carboxamide (50)

A solution of 49 (3.50 g, 5.71 mmol) in saturated methanolic ammonia (60 mL) was heated at 100°C for 16 h in a steel autoclave. The reaction mixture was cooled to room temperature and concentrated. The residues were triturated with toluene. (2 x 50 mL) to remove the benzamide. The residues were dissolved in a minimal amount of absolute ethanol and left at room temperature overnight. The crystals thus obtained were removed by filtration and the filtrate was then concentrated to give a second yield of product. The combined product was recrystallized once more from ethanol to a solid which was collected by filtration and dried in vacuo to give 1.0 g (68%): m.p. 178-180°C.

1H NMR (Me2SO-d6): δ 3.37-3.52 (m, 2H, C5.H), 3.78 (m, 1H, C4.H), 3.98 (m, 1H, C3.H), 4.19 (m, 1H, C2.H), 4.81, 5.05, 5.34 (3br s, 3H, 3 OH, D2O exchangeable), 5.38 (d, 1H, C1.H, J1.,2. = 4.2 Hz), 6.98 (bs, 1H, CONH2 ), 7.16 (bs, 1H, CONH2), 8.08 (s, 1H, C5H) and 10.98 (bs, 1H, C3OH).

Analysis - calculated for C9H13N3O6 (259.22): C, 41.70; H, 5.05; N, 16.21. Found: C, 41.52; H, 5.23; N, 16.40.

Example 34

1-azido-2,3-isopropylidine-β-L-ribofuranose (51)

To a solution of 2,3,5-tri-O-benzoyl-1-azido-β-L-ribofuranose (9.0 g, 18.48 mmol) in absolute methanol (60 mL) was added a 0.5 M solution of sodium methoxide (10.0 mL, 5.0 mmol). . The reaction mixture was stirred at room temperature overnight. TLC of the reaction mixture (hexane/ethyl acetate; 7:3) showed a complete transition of the starting substance to a more polar compound. the reaction mixture was neutralized with dry Dowex 50 H+ resin and the resin was removed by filtration. The filtrate was evaporated to dryness and dissolved in water (50 mL). The aqueous layer was extracted with dichloromethane (2×100 mL) to remove methyl benzoate and then the aqueous layer was concentrated in vacuo. The residues were then dried over phosphorus pentoxide and used in the next stage of synthesis without further determination of properties.

The above crude product (3.0 g, 17.14 mmol) was suspended in dry acetone (200 mL) and treated with 1,1-dimethoxypropane (50 mL) and vacuum dried Dowex 50 H+ (5.0 g) resin. The reaction mixture was stirred at room temperature for 2 h and filtered, and the resin was washed with dry acetone (100 mL). The filtrate was evaporated to dryness. The residues were purified by "flash" chromatography on silica gel using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and concentrated to give 3.60 g (97%) of the product as an oil.

1H NMR (CDCl3): δ 1.44 and 1.27 (2s, 6H, isopropylidene CH3), 2.70 (br s, 1H, C5.OH, exchangeable), 3.66 (m, 2H, C5.H), 4.34 (m, 1H, C4.H), 4.46 (d, 1H, C3.H), 4.72 (d, 1H, C2.H) and 5.50 (s, 1H, C1.H).

Example 35

1-azido-2,3-O-isopropylidine-5-O-tert-butyldimethylsilyl-β-L-ribofuranose (52)

To a solution of 1-azido-2,3-O-isopropylidine-β-L-ribofuranose (4.20 g, 20 mmol) in dry DMF (25 mL) was added imidazole (2.38 g, 35.0 mmol) and tert-butyldimethylsilyl chloride (4.50 g , 30.0 mmol). The reaction mixture was stirred at room temperature under an argon atmosphere overnight. TLC of the reaction mixture after 16 hours showed the complete conversion of the starting substance into the product. The solvent was removed in vacuo and the residue dissolved in dichloromethane (200 mL). The organic layer was washed with water (100 mL), saturated sodium bicarbonate (100 mL), and brine (100 mL), dried over sodium sulfate, and concentrated to give an oily product. Further purification by flash chromatography on silica gel using hexane/ethyl acetate (9:1) gave 6.22 g (94%) of the title compound as an oil:

1H NMR (CDCl3): δ 0.07 (s, 6H), 0.9 (s, 9H), 1.27 and 1.47 (2s, 6H, isopropylidene CH3), 3.66 (m, 2H, C5.H), 4.34 (m, 1H, C4.H), 4.46 (d, 1H, C3.H), 4.72 (d, 1H, C2·H) and 5.50 (s, 1H, C1.H).

Example 36

1-amino-2,3-O-isopropylidin-5-O-tert-butyldimethylsilyl-β-L-ribofuranose (53)

A mixture of 1-azido-2,3-O-isopropylidine-β-L-ribofuranose (6.0 g, 18 mmol) and Pd/C (0.25 g) in MeOH (50 mL) was hydrogenated at 50 psi on a Parr hydrogenator over night. The reaction mixture was filtered and the catalyst was washed with methanol (20 mL). The combined filtrate was evaporated to dryness and dried over P2O5 under vacuum overnight and used in this form for the next reaction without determining the properties. Yield 5.0 g (90%).

Example 37

Ethyl 5-amino-(2',3'-O-isopropylidine-5'-O-tert-butyldimethylsilyl-β-L-ribofuranosyl)imidazole-4-carboxylate (54)

With stirring, to a solution of 53 (5.0 g, 16.44 mmol) in dry CH2Cl2 (60 mL) was added a solution of ethyl N-cyano-N-(ethoxycarbonylmethyl)formimidate (4.0 g, 22.18 mmol; Robinson, D. H., et al, J. Chem. Soc., Perkin 1, 1715-1717, 1972) during 15 min. The reaction mixture was stirred at room temperature overnight under an argon atmosphere. The reaction mixture was diluted with CH2Cl2 (100 mL) and the organic layer was washed with saturated NaHCO3 (100 mL), water (50 mL), and brine (50 mL). The organic extract was dried and concentrated to give the crude product. The crude product was purified by flash chromatography on silica gel using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and evaporated to give 5.50 g (76%) as a white foam:

1H NMR (CDCl3): δ 0.28 (m, 6H), 1.1 (m, 9H), 1.55 (m, 9H), 4.00 (m, 2H, C5.H), 4.53 (m, 3H), 5.0 (m, 1H), 5.78 (m, 1H), 6.06 (d, 1H, C1.H) and 7.44 (s, 1H, C2H).

Example 38

5-amino-(2',3'-O-isopropylidine-5'-O-tert-butyldimethylsilyl-β-L-ribofuranosyl)imidazole-4-carboxamide (55)

A solution of 54 (5.0 g, 11.33 mmol) in methanolic ammonia (60 mL) was heated to 100°C in a steel autoclave for 12 h. The steel autoclave is cooled, carefully opened and concentrated. The crude product was purified by flash chromatography on silica gel using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and evaporated to give 4.0 g (88%) as a white foam.

Example 39

5-amino-(2',3'-O-isopropylidine-β-L-ribofuranosyl)imidazole-4-carboxamide (56)

Et3N⋅3HF (50 mmol) was added to a solution of 55 (4.0 g, 9.97 mmol) in dichloromethane (50 mL) at room temperature with stirring. The reaction mixture was stirred overnight and evaporated to dryness. The residues were purified by "flash" chromatography on silica gel using CH2Cl2 → EtOAc as eluent. The pure fractions were combined and evaporated to give 2.10 g (71%) as a white foam.

Example 40

5-amino-1-β-L-ribofuranosylimidazole-4-carboxamide (57)

With stirring, to a solution of 56 (2.0 g, 6.71 mmol) in dichloromethane (20 mL) was added 90% CF3COOH (20 mL) at 0°C. The reaction mixture was stirred at 0°C for 1 h and evaporated to dryness. The residues were co-evaporated with dry methanol (20 mL). This procedure was repeated three times to remove the last traces of TFA. The residue was treated with NH 4 OH (10 mL) and evaporated to dryness. The residues were combined with dry ethanol (3×20 mL). The residue was crystallized from ethanol to give 1.5 g (87%) of pure product.

Example 41

Methyl 1-β-L-(2',3', 5'-tri-O-benzoyl)ribofuranosyl-2-oxo-Δ4-imidazoline-4-carboxylate (59)

A mixture of methyl 2-oxo-Δ4-imidazoline-4-carboxylate 58 (542 mg, 3.82 mmol), hexamethyldisilazane (HMDS, 28 mL) and (NH4)2SO4 (75 mg, 0.56 mmol) was heated under reflux. After 40 min, a clear solution was formed and the reaction mixture was kept under reflux for a further 3.5 hours. Excess HMDS was evaporated and the product, a brown oil, was further dried under vacuum for a further 1 h.

A solution of 1-O-acetyl-2,3,5-O-tri-benzoyl-L-ribofuranose (1.93 g, 3.82 mmol) in anhydrous dichloroethane (28 mL) was added to the above dried silyl base at room temperature, then SnCl4 (1.39 g, 0.63 mL, 5.35 mmol) was added dropwise. After the addition, the reaction mixture was left to stand at room temperature overnight (~17 h). The reaction mixture was filtered through a pad of silica gel and washed with EtOAc. The EtOAc solution was washed with saturated NaHCO3 solution, filtered and washed twice with brine. The separated organic phase was dried over Na2SO4, concentrated and purified by flash chromatography on silica gel using (86% CH2Cl2, 14% EtOAc) to give 797 mg (36%) of the product as an off-white solid:

1H NMR (Me2SO-d6): δ 3.70 (s, 3H), 4.60 (dd, 1H, J1.,2. = 12.7, 6.6 Hz,), 4.70 (m, 2H), 5.93 (dd, 1H), 5.98 (d, 1H), 6.05 (dd, 1H), 7.46 (m, 6H), 7.63 (m, 3H), 7.71 (s, 1H), 7.91 (m, 6H) and 11.15 (s, 1H).

Example 42

1-β-L-ribofuranosyl-2-oxo-Δ4-imidazoline-4-carboxamide (60)

Compound 59 (1.26 g, 2.15 mmol) was dissolved in methanolic ammonia (45 mL, previously saturated with NH3 at 0°C). The solution was sealed in a steel autoclave and heated to 95°C for 15 h. The reaction mixture was cooled to room temperature, the solvent was evaporated and the residue was washed with CHCl 3 three times to remove the benzamide formed by the reaction. The residue was then added together with MeOH (15 mL) and heated under reflux. CHCl3 was added to the clear solution under reflux slowly until traces of the formed precipitate appeared. The hot mixture was rapidly filtered with suction and the filtrate solution was evaporated to dryness to give a light brown oil. The oil was quenched with anhydrous CH 3 CN to give a light brown solid: Yield 322 mg (58%); d.p. 174-178°C.

1H NMR (Me2SO-d6): δ 3.48 (m, 2H), 3.77 (m, 1H), 3.94 (m, 1H), 4.05 (m, 1H), 4.90 (m, 1H), 5.08 (d, 1H) , 5.30 (d, 1H), 5.36 (d, 1H), 7.30 (s, 1H), 7.31 (br s, 2H) and 10.47 (br s, 1H).

Example 43

2,3,5-tri-O-benzoyl-β-L-ribofuranosyl-1-carbonitrile (61)

With stirring, solutions of 1-O-acetyl-2,3,5-tri-O-benzoyl-β-L-ribofuranose (dried at 60°C, 1 mm, 12 h; 12.6 g, 24.9 mmol) in dry dichloromethane ( dried over magnesium sulfate and placed on molecular sieves, 125 mL) at 0-2°C, trimethylsilyl cyanide (dried over molecular sieves, 24 h; 4.70 mL, 37.50 mmol) was added in an argon atmosphere. To this reaction mixture, stannous chloride (1.0 mL, 8.67 mmol) was then added slowly, while maintaining the reaction temperature at 0-2°C. The resulting mixture was stirred and maintained at -5 to 0°C for a further 1.5 h. After 2 h, the reaction mixture was slowly added, with vigorous stirring, to a cold solution (5°C) of 10% sodium hydroxide (1.5 L) over 30 min and the mixture was maintained at 5-8°C during the addition. The layers were separated and the organic layer was washed with water (3×500 mL) until neutral and then dried over anhydrous magnesium sulfate. The organic extract was filtered and the drying agent was washed with dichloromethane (3×50 mL). The filtrate and eluates were combined and the solution was concentrated (<30°C, 20 mm) to a small volume and the remaining solution was filtered through a layer of celite. Further purification was achieved by flash chromatography on silica gel using dichloromethane as eluent. The dichloromethane solutions were combined and evaporated (<30°C, 20 mm) to give a white foam. The crude product was purified by flash chromatography on silica gel using dichloromethane as eluent. The pure fractions were combined and evaporated to obtain a syrup. The syrup was mixed with dry ethanol (100 mL) and the mixture was heated (approx. 60°C) to obtain a homogeneous solution. Cooling this solution to room temperature gave a white crystalline product. The crystalline solid was filtered and washed with cold ethanol and dried over P2O5 to give 7.47 g (63%) of 61: m.p. 55-57 °C.

1H NMR (CDCl3): δ 4.61 (m, 1H, C4.H), 4.78 (m, 2H, C5.H), 5.00 (d, 1H, C1.H), 5.88 (t, 1H, C3.H) , 6.05 (m, 1H, C2.H), 7.45-8.07 (m, 15H, PhH).

Example 44

2,3,5-tri-O-benzoyl-β-L (+)-ribofuranosyl alonthioamide (62)

H2S was passed through a suspension of L-cyanocarbonate 61 (6.10 g, 12.95 mmol) in dry ethanol (105 mL) for 10 min. N,N-dimethylaminopyridine (DMAP, 158 mg, 1.3 mmol) was then added to this solution. The reaction mixture was kept at 15-20 °C and saturated with H2S for 2.5 hours. (Caution: The starting substance that was a suspension was dissolved during the reaction). After 2.5 hours, the purging with H2S was stopped, the reaction mixture was stoppered and left to stir at room temperature overnight. The reaction mixture was checked by TLC the next morning (hexane/EtOAc; 7:3). TLC showed a complete transition of the starting material to halothioamide. The reaction mixture was cooled in an ice bath and argon was bubbled for 1 h to remove excess H2S. After that, the reaction mixture was concentrated on a rotavapor to obtain 6.20 g (95%) of foam.

1H NMR (CDCl3): δ 4.78 (m, 3H, C4.H and C5.H), 5.12 (d, 1H, C1.H), 5.72 (t, 1H, C3.H), 5.98 (m, 1H, C2.H), 7.45-8.12 (m, 15H, PhH) and 8.50 (br s, 2H, NH2).

Example 45

Ethyl 2-(2', 3', 5'-tri-O-benzoyl-β-L(+)-ribofuranosyl)thiazole-4-carboxylate (63)

Anhydrous NaHCO3 (8.4 g, 100 mmol) was added to a suspension of allothioamide 62 (5.05 g, 10 mmol) in dry 1,2-dimethoxyethane (DME, 100 mL) at 0°C with stirring. To this suspension under argon was added ethyl bromopyruvate (3.75 mL, 30 mmol) dropwise over 10 minutes. The reaction mixture was stirred at 0°C for 5 h under argon. The reaction mixture was analyzed by TLC (hexane/EtOAc; 7:3). TLC showed traces of starting material. The reaction mixture was left for a further 1 h at 0-5 °C, after which most of the starting material was converted into the product. The reaction mixture was then cooled to 15°C in an ice/acetone bath. A solution of 2,6-lutidine (7.0 mL, 60 mmol) and trifluoroacetic anhydride (4.16 mL, 30 mmol) in dry DME (20 mL) was then added dropwise through a funnel to the reaction mixture over 15 min. The temperature of the reaction mixture was then maintained at -15°C for 2 h under argon. Then the reaction mixture was filtered and concentrated. The residue thus obtained was dissolved in CH2Cl2 (200 mL) and the organic layer was washed with 5% NaHCO3 (100 mL), 1 N HCl (100 mL), 5% NaHCO3 (100 mL), water (100 mL), and brine ( 100 mL), dried and concentrated to a dark red oil.

The crude product was purified by flash chromatography on silica gel using hexane/EtOAc (7:3) as eluent to give 5.96 g (99%) of pure product:

1H NMR (CDCl3): δ 1.30 (t, 3H, CH2CH3), 4.30 (t, 2H, CH2CH3), 4.55-4.78 (m, 3H, C4.H) and C5.H), 5.72 (d, 1H), 5.82 (m, 2H), 7.25-8.04 (m, 15H, PhH) and 8.06 (s, 1H, C5H).

Example 46

Ethyl ester of β-L (+)-ribofuranosylthiazole-4-carboxylic acid (64)

Compound 63 (6.0 g, 10 mmol) was dissolved in dry ethanol (60 mL) (Caution: the compound was dissolved by heating with a hot air gun). To this solution was added NaOEt powder (200 mg, 3.0 mmol) under argon. The reaction mixture was stirred under argon overnight. The reaction mixture was checked by TLC using hexane/EtOAc 7:3 and EtOAc/MeOH 9:1). TLC showed a complete transition of the starting substance to a more polar product. then the reaction mixture was neutralized with dry Dowex SX-8 H+ resin. The resin was removed by filtration and the filtrate was concentrated under vacuum on a rotavapor. The brown colored residue was then purified by flash chromatography on silica gel using EtOAc → MeOH. Pure fractions were combined and concentrated to give 2.31 g (77%) of pure product.

1H NMR (CDCl3): δ 1.30 (t, 3H, CH2CH3), 3.56 (m, 2H, C5.H), 3.86 (m, 2H), 4.0 (m, 1H), 4.26 (t, 2H, CH2CH3), 4.82-5.04 (3m, 3H, 3OH), 5.42 (d, 1H, C1.H) and 8.46 (s, 1H, C5H).

Example 47

β-L(+)-ribofuranosylthiazole-4-carboxamide (65)

A solution of 64 (1.0 g, 3.32 mmol) in methanolic ammonia (50 mL) was stirred at room temperature in a steel autoclave. After 17 h, the autoclave was cooled, carefully opened and the solution was evaporated to a residue. The residues were chromatographed by "flash" chromatography on a silica-gel column using ethyl acetate and methanol (9:1) as eluent. The product was crystallized from absolute ethanol. Yield 580 mg (67%): m.p. 146-148 °C.

1H NMR (Me2SO-d6): δ 3.48 (m, 2H, C5.H), 3.85 (m, 2H), 4.03 (m, 1H), 4.80 (t, 1H, C5.OH), 4.88 (d, 1H , C3.OH), 5.32 (d, 1H, C2.OH), 5.02 (d, 1H, C1.H, J1.,2. = 5.1 Hz), 7.52 (bs, 1H, CONH2), 7.64 (bs, 1H, CONH2) and 8.16 (s, 1H, C5.H).

Analysis - calculated for C9H12N2SO5 (260.2): C, 41.53; H, 4.65; N, 10.76; S, 12.32. Found: C, 41.73; H, 4.60; N, 10.55; S, 12.25.

Example 48

β-L-ribofuranosyl-1-carboximidic acid methyl ester (66)

Sodium methoxide (0.358 g, 6.64 mmol, 0.5 M solution) was added to a suspension of 2,3,5-tri-O-benzoyl-β-L-ribofuranosyl cyanide (14.13 g, 30.0 mmol) in dry methanol (60 mL) with stirring. , Fluka) in an argon atmosphere. The solution, which becomes homogeneous after 5 min, was stirred for 2.5 h at room temperature. The reaction mixture was neutralized with Dowex 50W-X8 H+ resin (dried at 100 °C under 0.05 mm Hg for 16 h; 3.0 g, 5.1 mol-eq/g). The resin was filtered and the solvent was removed below 40°C on a rotavapor. The thus obtained residues were washed with methanol. The methanol washes were concentrated to give the second and third yields of 66. The three yields were combined and recrystallized from dry methanol to give 4.35 g (66%): m.p. 140-142 °C.

1H NMR (CDCl3): δ 3.46 (s, 3H, OCH3), 3.50-3.80 (m, 5H), 3.98 (d, 1H), 4.98 (br s, 3H) and 8.27 (s, 1H, NH).

Example 49

2-[(aminocarbonyl)carbonyl]-1-(β-L-ribofuranosylaminomethyl)hydrazine (67) '

Methyl imidate 66 (4.83 g, 25.26 mmol) and oxamidohydrazide (2.68 g, 26.00 mmol) were dissolved in dry dimethyl sulfoxide (100 mL). The reaction solution was stirred for 20 h at room temperature, the solvent was predistilled at 55°C in a vacuum. The remaining solid was suspended in methanol, the soluble fraction was collected by filtration (the insoluble fraction was unreacted hydrazide) and concentrated to about 25 mL. By adding this solution dropwise to acetonitrile (500 mL), a white precipitate was obtained: yield 4.35 g (66%).

1HNMR (Me2SO-d6): δ 3.47-3.60 (m, 2H), 3.3.60-3.88 (m, 3H), 4.07 (d, 1H), 4.15 (d, 1H), 4.85-5.2 (br s, 2H ), 7.70, 8.09 (2 br s, 2H) and 10.05 (br s, 1H, C=NH).

Example 50

3-β-L-ribofuranosyl-1,2,4-triazole-5-carboxamide (C-ribavirin; 68)

Compound 67 (4.0 g, 15.2 mmol) was heated under vacuum (0.1 mm) at 135°C for 15 min. After the flask was cooled, the vitreous substance was treated with methanol and heated in an oil bath. During this process, a precipitate began to form. After approximately 2 hours, the solid was separated, and the second yield was obtained after concentrating the filtrate. The total product yield was 2.65 g (71%): m.p. 193-195 °C.

1H NMR (Me2SO-d6): δ 3.43 (m, 2H, C5.H), 3.75 (m, 1H, C4.H), 3.88 (m, 1H, C3.H), 4.12 (m, 1H, C2. H), 4.57 (d, 1H, C1.H, J1.,2. =5.7 Hz), 7.62 (bs, 1H, CONH2), 7.86 (bs, 1H, CONH2) and 10.0 (bs, 1H, NH).

Analysis - calculated for C8H12N4O5 (244.2): C, 39.35; H, 4.95; N, 22.94. Found: C, 39.38; H, 4.73; N, 22.43.

Example 51

5-O-trityl-2,3-O-isopropylidene-β-L-ribofuranose (69)

To a solution of 2,3-O-isopropylidene-β-L-ribofuranose (10.5 g, 55.26 mmol) in dry pyridine (100 mL) under argon was added a catalytic amount of DMAP (12.2 mg, 0.1 mmol). With stirring, trityl chloride (15.56 g, 56.0 mmol) was added to the solution. The reaction mixture was stirred under an argon atmosphere overnight at room temperature. The pyridine was removed under vacuum and the residue was dissolved in CH2Cl2 (250 mL) and the organic layer was washed with 10% NaHCO3 solution (2×100 mL) and brine (100 mL). The organic layer was dried over Na2SO4 and concentrated in vacuo. The thus obtained residues were purified by "flash" chromatography on a silica-gel column using hexane → EtOAc as eluent. The pure fractions were combined and concentrated to give 15.74 g (69%) of product:

1H NMR (CDCl3): δ 1.27 and 1.41 (2s, 6H, isopropylidene CH3), 3.25-3.56 (m, 2H, C5.H), 3.86 (m, 2H), 4.0 (m, 1H), 4.70 (m, 1H), 5.24 (d, 1H, J1.,2. = 3.50 Hz, C1.H) and 7.17-7.35 (m, 15H, PhH).

Example 52

3-ethoxycarbonyl-2-oxopropylidenetriphenyl-phosphorane (70)

A solution of {3-(ethoxycarbonyl)-2-oxopropyl}triphenyl phosphonium chloride (21.34 g, 500 mmol) in water (450 mL) was added to a solution of sodium carbonate (3.1 g, 25.0 mmol) over 10 min (Caution: Immediately after addition, white precipitate). The reaction mixture was stirred at room temperature overnight. The resulting precipitate was filtered through a sinter funnel. The precipitate was dissolved in dichloromethane (100 mL), dried over sodium sulfate and concentrated to give a white solid 18.13 g (93%). This material was dried over phosphorus pentoxide overnight.

1H NMR (CDCl3): δ 1.26 (t, 3H), 3.34 (s, 2H), 3.76-3.84 (d, 1H) 4.19 (m, 2H) and 7.48-7.68 (m, 15H, PhH).

Example 53

Ethyl 4-(2',3'-O-isopropylidene-5'-O-trityl-α- and β-L-ribofuranosyl)-3-oxobutanoate (71)

A mixture of 70 (10.9 g, 25.23 mmol) and 3-ethoxycarbonyl-2-oxopropylidenetriphenyl phosphorane (11.8 g, 30 mmol) in anhydrous acetonitrile (30 mL) was refluxed for 90 h. The solvent was evaporated under reduced pressure and the residues were subjected to flash chromatography on a silica gel column. Elution with hexane-ethyl acetate (9:1) gave the product (β:α ca. 2:1) as a foam (10.15 g, 74%).

Example 54

Ethyl 2-diazo-4-(2',3'-O-isopropylidene-5'-O-trityl-α- and -β-L-ribofuranosyl)-3-oxobutanoate (72)

Triethylamine (1.83 g, 18.1 mmol) and toluene p-sulfonyl azide (10 mL) were added one after the other to a solution of 71 (9.85 g, 18.08 mmol) in anhydrous acetonitrile (50 mL). The mixture was kept at room temperature for 30 min. The solvent was then evaporated under reduced pressure and the residues were subjected to flash chromatography on a silica gel column. Elution with hexane-ethyl acetate (9:1) gave 8.90 g (86%) of 72 (β:α ca. 1:1) as a foam.

Example 55

Ethyl 4-hydroxy-3-(2',3'-O-isopropylidene-5'-O-trityl-β-L-ribofuranosyl)pyrazole-5-carboxylate (73)

A solution of 72 (8.53 g, 14.92 mmol) in dry DME (60 mL) was added dropwise, with stirring, to a suspension of ice-cold sodium hydride (NaH) (60% dispersion; 1.80 g, 75.0 mmol) in dry DME (60 mL). ) under argon for 30 min. The reaction temperature gradually increased to 20°C, and the mixture was additionally stirred for a further 3 h at room temperature. The mixture was analyzed by TLC using hexane/EtOAc (3:1) or dichloromethane/EtOAc (9:1). TLC indicated completion of the reaction. A solution of acetic acid (4.50 mL, 75.0 mmol) in DME (10 mL) was then added dropwise, with stirring, to the ice-cold reaction mixture. The solvent was evaporated under reduced pressure to give a residue to which water (50 mL) and diethyl ether (100 mL) were added. The ether layer was separated, dried over anhydrous sodium sulfate and concentrated. The residues were subjected to "flash" chromatography on silica gel with hexane-ethyl acetate (3:1) as eluent. Pure fractions were collected and evaporated to give 73 as a β:α mixture (6.40 g, 73%):

1H NMR (CDCl3): δ 1.31 (t, 3H), 1.42-1.65 (m, 6H), 3.19-3.27 (m, 2H), 4.44-4.75 (m, 3H), 4.75 (m, 1H), 5.19 ( d, 1 H), 6.99 (br s, OH, exchangeable), 7.26-7.51 (m, 15H, PhH).

Example 56

4-hydroxy-3-(2',3'-O-isopropylidene-5'-O-trityl-β-L-ribofuranosyl)pyrazole-5-carboxamide (74)

A solution of ester 73 (6.30 g, 10.7 mmol) in dry methanolic ammonia (70 mL) was heated to 90-95°C in a steel autoclave for 12 h. The solvent was evaporated under reduced pressure and the residue was flash chromatographed on silica gel using hexane/ethyl acetate (3:2) as eluent. The required fractions were combined and evaporated to give 4.54 g (78%) of a glassy product containing a β:α mixture.

1H NMR(CDCl3): δ 1.40-1.62 (2s, 6H), 3.11-3.24 (m, 2H), 4.37 (m, 1H), 4.65 (m, 1H), 5.11 (dd, 1H), 5.27 (d , 1H), 6.99 (br s, OH, exchangeable) and 7.23-7.50 (m, 17H).

Example 57

3-β-L-ribofruanosyl-4-hydroxypyrazole-5-carboxamide (L-pyrazomycin; 75)

A solution of 74 (4.40 gm, 8.13 mmol) in 90% CF3CO2H (20 mL) was stirred at room temperature for 45 min. The solvent was then removed at 5°C under reduced pressure to give a white solid (1.90 g, 90.48%). The residues thus obtained were chromatographed on a "flash" column of silica gel with EtOAc-iPrOH-H2O (4:1:2) as eluent. Fractions containing a pure compound of β and α isomers were pooled separately and evaporated at <20°C. Recrystallization from water gave 800 mg of the pure β isomer: m.p. 111-113 °C;

1H NMR of β-isomer (D2O): δ 3.73-3.78 (m, 2H), 4.0 (m, 1H), 4.19 (m, 1H), 4.35 (m, 1H) and 4.90-4.93 (d, 1H, J1. ,2. = 7.42 Hz).

Analysis - calculated for C9H13N3O6 (259.22): C, 41.70; H, 5.05; N, 16.21. Found: C, 41.88; H, 5.04; N, 16.58. Yield of isolate α:β mixture 1.90 g, (90%).

100 mg of the isomer was isolated as a foam.

1H NMR of α isomer (D2O): δ 3.65-3.85 (m, 2H), 4.06-4.11 (m, 1H), 4.32-4.41 (m, 2H) and 5.20 (d, 1H, J1.,2. = 3.30 Hz ).

Analysis - calculated for C9H13N3O6: C, 41.70; H, 5.05; N, 16.21. Found: C, 41.91; H, 5.08; N, 16.02.

1.0 g of an indistinguishable mixture of L-pyrazomycin was also separated.

The purity of the α:β isomer was also determined by C18 reversed-phase HPLC using a 0-10% acetonitrile gradient in water. The retention time of the α isomer is Rt 5,716, and of the β isomer 7,135. The purity of the β and α mixture of L-pyrazomycin was found to be greater than 99% by HPLC.

Example 58

Preparation of 2,5-anhydro-L-haloamidine hydrochloride (76)

Methyl 2,5-anhydro-L-alonimidate (3.82 g, 20.0 mmol) and ammonium chloride (1.07 g, 20.0 mmol) were dissolved in methanolic ammonia (60 mL, saturated at ice-acetone temperature for 1 h). Later, this mixture allowed to stir at room temperature in a thick-walled steel autoclave for 16 h at room temperature. The steel autoclave was cooled, carefully opened and the solution evaporated to dryness. The resulting solid was dried to yield 4.10 g of the title compound as a quantitative yield.

Example 59

2-(β-L-ribofuranosyl)pyrimidine-6(1H)-oxo-4-carboxylic acid (77)

To a solution of 2,5-anhydro-L-haloamidine hydrochloride (4.0 g, 18.66 mmol) in water (60 mL) was added sodium hydroxide (1N, 20 mL, 20.0 mmol) and ethyl sodium oxaloacetate (4.20 g, 20.0 mmol). The reaction mixture was allowed to stir at room temperature for 16 h and then neutralized to pH 2 with H+ resin (Dowex 50W-X8). The reaction mixture was filtered and concentrated to the smallest volume. Silica gel was added and evaporated to dryness. The resulting powder was placed on top of a "flash" column and eluted with a mixture of ethylacetate/acetone/methanol/water (3/1/1/1) until the faster moving compound was eluted. The column was then eluted with methanol and the fractions containing the compound were combined and the methanol was removed and the fractions containing the compound were combined and the methanol was removed to give a brown hygroscopic compound. The yield of the isolate was 4.50 g (89%). This compound was used as such in the next step without determining its properties.

Example 60

Ethyl 2-(β-L-ribofuranosyl)pyrimidine-6(1H)-oxo-4-carboxylate (78)

A well-dried suspension of acid 77 (4.50 g, 16.5 mmol) in dry ethanol (100 mL) was cooled in an ice bath and dry hydrogen chloride was bubbled through for 5 min. To this reaction mixture was added triethyl orthoformate (20 mL) and the mixture was allowed to stir for 24 h at room temperature. The solvent was removed under vacuum and the resulting dark colored solid was subsequently purified by flash column chromatography using a mixture of dichloromethane/methanol (9/1). The pure fractions were combined and concentrated to yield 4.55 g (92%) of the solid compound. Since this compound was found to be impure, it was subsequently converted to the corresponding tetra acetate with a yield of 47%. Tetra acetate was purified by column chromatography.

Example 61

2-(β-L-ribofuranosyl)pyrimidine-6(1H)-oxo-4-carboxamide (79)

A solution of the above-mentioned tetra acetate ester (1.80 g, 4.22 mmol) in saturated methanolic ammonia (60 mL) was heated to 100 °C in a steel autoclave for 17 h. The reaction mixture was cooled and concentrated to give a white solid. The solid was then triturated with ethyl acetate and filtered. The solid was recrystallized from ethanol to give 0.83 g (82%) of pure product as a white solid: m.p. 200-202 °C.

1H NMR (Me2SO-d6) δ 3.35-3.57 (m, 2H, C5.H), 3.84 (m, 1H, C4.H), 3.98 (m, 1H, C3.H), 4.22 (m, 1H, C2 .H), 4.75 (t, 1H, C5.OH, D2O exchangeable), 4.80 (d, 1H, C1.H, J1.,2.=5.77 Hz), 4.89 (d, 1H, C3.OH, D2O exchangeable ), 5.15 (d, 1H, C2.OH, D2O exchangeable), 7.85 (d, 1H), 7.98 (bs, 1H, CONH2), 8.19 (bs, 1H, CONH2) and 9.0 (d, 1H, NH).

Analysis - calculated for C10H13N3O4 (239.23): C, 44.28; H, 4.83; N, 15.49. Found: C, 44.58; H, 5.17; N, 15.28.

Example 62

Methyl (3-L-arabinopyranoside (81)

To a suspension of L-arabinose (100 g, 667 mmol) in anhydrous MeOH (450 mL) was added a solution of HCl/MeOH (7.3 g dry HCl in 50 mL MeOH) at room temperature under an argon atmosphere. The mixture was refluxed for 2 h and cooled to room temperature. The solution is concentrated to about 3/4 of its volume to obtain a suspension. The solid precipitate was filtered and washed with cold MeOH (20 mL) to give the first yield as a crystalline powder (35.23 g). The filtrate was concentrated (35°C) to 1/4 of its volume. The solid precipitate was filtered, washed and dried to give a second yield (9.66 g) as a colorless crystalline powder. Concentration and filtration were repeated to obtain an additional 28.31 g of product (total 73.2 g, 67 %).

1H NMR (D2O): δ 3.30 (s, OCH3, 3H), 3.56 (dd, 1H, H5), 3.73 (m, 1H, H4), 3.77 (dd, 1H, H5), 3.82 (bs, 1H, H2), 4.73 (m, 1H, H1).

Example 63

Methyl 3,4-isopropylidene-β-L-arabino-pyranoside (82)

To a mixture of methyl β-L-arabinopyranoside 81 (23.33 g, 142.26 mmol) and dimethoxypropane (55 mL, 448 mmol) in dry DMF (185 mL) was added Amberlyt 15 (H+ form, 1.42 g) and the suspension was stirred at room temperature for 18 h. The solution was evaporated to give a syrup, which was dissolved in EtOAc (200 mL) and washed with brine (50 mL), saturated NaHCO 3 , and brine (20 mL). The aqueous washes were combined and extracted with EtOAc (5×20 mL), which were then washed with NaCl/H2O and combined with the organic solution. The EtOAc solution was dried over anhydrous Na 2 SO 4 and evaporated to dryness to give a syrup (29.2 g, quant.).

1H NMR (CDCl3): δ 1.36 and 1.53 (2s, 6H, isopropylidene-CH3), 2.43 (d, 1H, 2'-OH), 3.44 (s, 3H, OCH3), 3.78 (m, 1H, H2), 3.93 (s, 2H, H5), 4.15-4.25 (m, 2H, H3 & H4), 4.71 (d, 1H, H1).

Example 64

Methyl 3,4-isopropylidene-2-O-[(methylthio)thiocarbonyl)-β-L-arabino-pyranoside (83)

The above syrup 82 (29.2 g, 142.26 mmol) was dissolved in anhydrous THF (190 mL) and cooled to 0°C. NaH (55-65%, 6.9 g, 172.5 mmol) was added to the solution slowly under an argon atmosphere. The suspension was refluxed for 2 h and cooled to 0°C. Carbon disulfide (21 mL, 349.14 mmol) was added to the mixture and the resulting dark mixture was stirred at room temperature for 2 h. Methyl iodide (12.4 mL, 160.64 mmol) was added to the mixture at 0°C and the mixture was stirred for 16 h. The mixture was poured into ice-water (300 mL) and extracted with EtOAc (3×50 mL). The EtOAc solution was dried and evaporated until crystals precipitated. The suspension was left in the freezer for 16 h. The crystals were filtered and washed with hexane to give the first yield (21.61 g) as a yellowish powder. The filtrate was concentrated, kept at 0°C overnight and filtered to give a second yield (16.51 g). This was repeated two more times to give an additional 1.44 g of product (39.62 g, two stages two stages of 81 (94.7%). M.p. 127-130°C°.

1H NMR (CDCl3): δ 1.39 and 1.55 (2s, 6H, isopropylidene-CH3), 2.60 (s, 3H, SCH3,), 3.40 (s, 3H, OCH3), 4.01 (s, 2H, H5), 4.30 ( m, 1H, H4), 4.50 (dd, 1H, H3), 4.98 (d, 1H, H1), 5.78 (dd, 1H, H2).

Example 65

Methyl 2-deoxy-β-L-erythro-pentopyranoside (84)

Compound 83 (40 g, 136 mmol) and AIBN (24.61 g, 150 mmol) were dissolved in dry dioxane (400 mL) by heating in an oil bath (100°C). The mixture was flushed with argon at 100°C for 15 min, after which diphenylsilane (51.4 mL, 272 mmol) was added. The temperature of the oil bath was increased to 130°C and the mixture was refluxed for 16 h. More diphenylsilane (2 mL, 10.8 mmol) and AIBN (1.27 g, 7.7 mmol) were added and refluxing was continued for a further 5 h. More AIBN (0.2 g, 1.2 mmol) was added and refluxing was continued for a further 1 h. The mixture was cooled and evaporated to give compound 84 as a syrup, which was mixed with 80% HOAc (544 mL) and stirred at room temperature for 16 h. The mixture was evaporated to give a syrup which was partitioned between water and ether. The aqueous layer was washed with ether and the combined organic layer was extracted with water. The aqueous solution was evaporated to give compound 85 as a syrup (16.36 g, 81.4% for two steps of 83).

1H NMR (CDCl3): δ 1.89 (dd, 2H, H2), 2.30 (d, 1H, OH), 2.47 (d, 1H, OH), 3.35 (s, 3H, OCH3), 3.88-3.69 (m, 3H , H4 & H5), 4.03 (m, 1H, H3), 4.79 (t, 1H, H1).

Example 66

2'-deoxy-β-L-erythro-pentose (86)

Compound 85 (16.36 g, 110.5 mmol) was dissolved in 0.8 M aqueous HCl solution (546 mL) and the resulting mixture was stirred at room temperature for 72 h. The mixture was neutralized with 1 N aqueous NaOH to pH 6-7 and then evaporated to give a syrup. The crude material was purified on a silica gel column (4×15 cm) eluting with CH2Cl2/MeOH (1:0 to 95:5). Appropriate fractions were combined to give compound 86 as a syrup (10.53 g, 71.1 %).

Example 67

Methyl 2'-deoxy-β-L-erythro-pentose (87)

Compound 86 (15.68 g, 117.0 mmol) was dissolved in dry MeOH (342 mL) and 1% HCl/MeOH (35 mL) was added to the resulting solution. The solution was kept at room temperature for 1 h and neutralized with Py (55 mL) at 5°C to pH ~ 6. The mixture was evaporated with silica gel and purified on a silica gel column (1×5 cm), and eluted with CH2Cl2 /MeOH (98:2 to 96:4) to give compound 87 as a syrup (13.94 g, 80.5%).

1H NMR (CDCl3): δ 2.22-2.44 (m, 2H, H2), 3.50 and 3.59 (2s, 3H, OCH3), 3.75-3.88 (m, 2H, H5), 4.26 (m, 1H, H4), 4.66 (m, 1H, H3), 5.25 (t, 1H, H1).

Example 68

Methyl 2'-deoxy-3,5-di-O-p-toluoyl-L-erythro-pentose (88)

Compound 87 (9.00 g, 60.8 mmol) was dissolved in pyridine (180 mL) and cooled in an ice-water bath. To this cold solution was added toluoyl chloride (18 mL, 00 mmol) over 30 min and the resulting solution was stirred at room temperature for 16 h. The mixture is evaporated to dryness. The mixture was extracted with EtOAc, washed with brine, dried and evaporated. The crude product was purified on a silica gel column (3×15 cm) using hexane/EtOAc (1:0 to 5:1) as eluent. Evaporation of the corresponding fractions gave compound 88 in syrup form (22.638, 97%).

1H NMR (CDCl3): δ 2.40 (2s, 6H, 2×CH3), 3.35 (s, 3H, OCH3 β-anomer), 3.41 (s, 3H, OCH3 α-anomer), 4.6-4.5 (m, H4 and H5 of both anomers), 5.19 (d, 1H, H1 α-anomer), 5.21 (dd, 1H, H1 β-anomer), 5.41 (m, 1H, H3 α-anomer), 5.59 (m, 1H, H3 α- anomer), 7.18-8.02 (m, 8H, aromatic),

Example 68

2'-deoxy-3',5'-di-O-p-toluoyl-α-L-erythro-pentofuranosyl chloride (13)

Compound 88 (22 g, 57.3 mmol) was dissolved in dry ether (200 mL) and the solution was cooled to 0°C in an ice bath. The solution was washed with dry HCl for ~5 min until the mixture crystallized. The reaction mixture was then kept under refrigeration overnight. The solid that settled was filtered and washed with cold ether. The solid was immediately dried under vacuum over NaOH to give compound 13 as a colorless crystalline powder (19.28 g). The filtrate was concentrated and treated with HCl and kept overnight in the refrigerator. Filtration, washing and drying gave an additional 1.2 g of product (total 20.48 g, 92%), m.p. 118-121 °C.

1H NMR (CDCl3): δ 2.39 (2s, 6H, aromatic-CH3), 2.82 (m, 2H, H2), 4.65 (m, 2H, H5), 4.86 (q, 1H, H4), 5.57 (m, 1H , H3), 6.48 (d, 1H, H1), 7.25 (2d, 4H, aromatic-H), 7.95 (2d, 4H, aromatic-H).

Example 69

Methyl 1-(2'-deoxy-3',5'-di-O-p-toluoyl-β-L-erythro-pentofuranosyl)-1,2,4-triazole-5-carboxylate (89), methyl 1-(2 '-deoxy-3',5'-di-O-p-toluoyl-β-L-erythro-pentofuranosyl)-1,2,4-triazole-2-carboxylate (90) and methyl 1-(2'-deoxy-3 ',5'-di-O-p-toluoyl-β-L-erythro-pentofuranosyl)-1,2,4-triazole-3-carboxylate (91)

To a solution of methyl 1,2,4-triazole-3-carboxylate (1.278, 10 mmol) in dry acetonitrile (50 mL) was added sodium hydride (60% in oil, 0.5 g, 12.5 mmol). The mixture was stirred at room temperature for 30 min. Dry and powdered chlorocarbon was added and the suspension was stirred at room temperature for 16 h. The mixture was evaporated to give a residue which was diluted between water/EtOAc and extracted into EtOA. The aqueous solution was extracted with EtOAc. The combined EtOAc solution was washed with brine and evaporated to dryness. The mixture was purified on a silica gel column (3×20 cm) using EtOAc/hexane (1.2:1) as eluent to give 89 (1.72 g), 90 (0.98 g) and 91 (0.45 g).

1H NMR (CDCl3): 89: δ 2.52 (2s, 6H, CH3), 2.82 (m, 1H, H2.), 3.45 (m, 1H, H2.), 4.60 (dd, 1H, H5.), 4.72 ( dd, 1 H, H5.), 4.76 (m, 1 H, H4.), 6.03 (m, 1H, H3.), 7.29-7.38 (m, 5H, aromatic-H and H1.), 7.97-8.12 ( m, 5H, aromatic-H and C5H). 90: 8 2.50 & 2.53 (2s, 6H, CH3), 2.95 (m, 1H, H2.), 3.20 (m, 1H, H2.), 4.09 (s, 3H, OCH3, ), 4.72 (m, 3H, H4. & H5.), 5.83 (m, 1H, H3.), 6.47 (t, 1H, H1.), 7.36 (dd, 4H, aromatic-H), 8.02 (dd, 4H, aromatic-H), 8.51 (s, 1H, C6H), 91 : δ 2.53 (m, 7H, H2. & 2×CH3), 3.16 (m, 1H, H2.), 4.13 (s, 3H, OCH3), 4.69-4.85 (m, 3H, H4. & H5.), 5.73 (m, 1H, H3.), 6.88 (q, 1H, H1.), 7.35 (dd, 4H, aromatic-H), 7.94 & 8.05 (dd, 4H, aromatic- H), 8.76 (s, 1H, C6H).

Example 70

1-(2'-deoxy-β-L-erythro-pentofuranosyl)-1,2,4-triazole-5-carboxamide (92)

A mixture of 89 (1.77 g, 3.70 mmol) and a saturated solution of methanolic ammonia (40 mL) was heated in a steel autoclave at 55°C for 16 h. After cooling, the solution was evaporated onto silica gel and purified on a silica gel column eluting with CH 2 Cl 2 /MeOH (10:1) to give compound 92 as a colorless powder (297 mg, 35%).

1H NMR (DMSO-d6): δ 2.27 (m, 1H, H2.), 2.60 (m, 1H, H2.), 3.32 (m, 1H, H5.), 3.48 (m, 1H, H5.), 3.80 (m, 1H, H4.), 4.41 (m, 1H, H3.), 7.12 (t, 1H, H1.), 8.06 (s, 1H, NH), 8.14 (s, 1H, C6H), 8.27 (s , 1H, NH).

Example 71

1-(2'-deoxy-β-L-erythro-pentofuranosyl)-1,2,4-triazole-3-carboxamide (93)

A mixture of 91 (0.45 g, 0.94 mmol) and a saturated solution of methanolic ammonia (20 mL) was heated in a steel autoclave at 55°C for 16 h. After cooling, the solution was evaporated onto silica gel and purified on a silica gel column eluting with CH2Cl2/MeOH (10:1) to give 93 (54 mg, 25%).

1H NMR (DMSO-d6): δ 2.24 (m, 1H, H2.), 2.38 (m, 1H, H2.), 3.61 (m, 2H, H5.), 3.85 (m, 1H, H4.), 4.30 (m, 1H, H3.), 6.70 (t, 1H, H1.), 7.94 (s, 1H, NH), 8.33 (s, 1H, NH) 8.98 (s, 1H, C5H).

Example 72

1-(2'-deoxy-3',5'-di-O-p-toluoyl-β-L-erythro-pentofuranosyl)-2, 4-dicyanopyrrole (94)

To a solution of 2,4-dicyanopyrrole (302 mg, 2.58 mmol) in dry acetonitrile (25 mL) was added sodium hydride (60% in oil, 125 mg, 2.6 mmol). The mixture was stirred at room temperature for 30 min. Chlorocarbon 13 (1 g, 2.58 mmol) was added and the suspension was stirred at room temperature for 16 h. The mixture was evaporated to give a solid residue which was diluted between water and EtOAc. The aqueous solution was extracted with EtOAc. The combined EtOAc extract was washed with water and brine, dried and evaporated to dryness. The product was purified on a silica gel column (3×20 cm) using hexane/EtOAc (5:2) as eluent to afford 94 as an oil (605 mg, 50%).

1H NMR (CDCl3): δ 2.29 (s, 3H, aromatic-CH3), 2.55 (s, 3H, aromatic-CH3), 2.67 (m, 1H, H2.), 2.98 (m, 1H, H2.), 4.74 -4.89 (m, 3H, H4. & H5.), 5.77 (m, 1H, H3.), 6.36 (t, 1H, H1.), 7.18 (s, 1H, C6H), 7.38 (m, 4H, aromatic -H), 7.68 (s, 1H, C3H), 7.97 (d, 2H, aromatic-H), 8.05 (d, 2H, aromatic-H).

Example 73

1-(2'-deoxy-β-L-erythro-pentofuranosyl)-2, 4-dicyanopyrrole (95)

A mixture of 94 (605 mg, 1.29 mmol) and saturated methanolic ammonia solution (20 mL) was heated in a steel autoclave at 65°C for 16 h. After cooling, the solution was evaporated to dryness. The crude product was purified on a silica gel column eluting with CH2Cl2/MeOH (10:1) to give 95 (158 mg, 52%).

1H NMR (CD3OD): δ 2.55 (m, 2H, H2.), 3.82 (m, 2H, H5.), 4.08 (m, 1H, H4.), 4.53 (m, 1H, H3.), 6.38 (t , 1H, H1.), 7.37 (s, 1H, C5H), 8.19 (s, 1H, C3H).

Example 74

1-(2'-deoxy-β-L-erythro-pentofuranosyl)pyrrole-2,4-dicarboxamide (96)

To a solution of 95 (90 mg, 0.385 mmol) in aqueous NH4OH (29.6%, 9 mL) was added H2O2. The solution was stirred at room temperature for 2 h and evaporated to dryness. The residue was purified on a silica gel column eluting with CH2Cl2/MeOH (10:1) to give compound 96 (75 mg, 72%).

1H NMR (CD3OD): δ 2.31 & 2.61 (m, 2H, H2.), 3.89 (m, 2H, H5.), 4.04 (m, 1H, H4.), 4.45 (m, 1H, H3.), 6.93 (t, 1H, H1.), 7.24 (s, 1H, C6H), 8.09 (s, 1H, C3H).

Example 75

Methyl 1-(2'-deoxy-3',5'-di-O p-toluoyl-β-L-erythro-pentofuranosyl)pyrazole-3,5-dicarboxylate (97)

To a solution of methyl pyrazole-3,5-dicarboxylate (458 mg, 2.5 mmol) in dry acetonitrile (25 mL) was added sodium hydride (60% in oil, 144 mg, 3.0 mmol). The mixture was stirred at room temperature for 30 min. Chlorocarbon 13 (970 mg, ∼95%, 2.5 mmol) was added and the suspension was stirred at room temperature for 4 h. The mixture was evaporated to dryness and the residue was purified on a silica gel column (3×7 cm) using hexane/EtOAc (5:2) as eluent to give 97 as an oil (470 mg, 35%).

1H NMR (CDCl3): δ 2.40 (d, 6H, aromatic-CH3), 2.70 (m, 1H, H2.), 3.60 (m, 1H, H2.), 3.93 (d, 6H, OCH3), 4.48-4.65 (m, 3H, H4. & H5.), 5.89 (m, 1H, H3.), 7.18-7.29 (m, 5H, aromatic-H & H1.), 7.38 (s, 1H, C6H), 7.90 (m , 4H, aromatic-H).

Example 76

1-(2'-deoxy-β-L-erythro-pentofuranosyl)pyrazole-3, 5-dicarboxamide (98)

A mixture of 97 (270 mg, 0.51 mmol) and a saturated solution of methanolic ammonia (20 mL) was heated in a steel autoclave at 100°C for 16 h. After cooling, the solution was evaporated on a silica gel column using CH 2 Cl 2 /MeOH (10:1) to give 98 as a colorless powder (189 mg, 73%).

1H NMR (DMSO-d6): δ 2.25 (m, 1H, H2.), 2.89 (m, 1H, H2.), 3.42 (m, 1H, H5.), 3.59 (m, 1H, H5.), 3.86 (q, 1H, H4.), 4.55 (m, 1H, H3.), 4.77 (t, 1H, OH), 5.27 (d, 1H, OH), 7.17 (t, 1H, H1.), 7.29 (s , 1H, C4H), 7.51 (s, 1H, NH), 7.66 (s, 1H, NH), 7.80 (s, 1H, NH), 8.19 (s, 1H, NH).

Example 77

Methyl 1-(2'-deoxy-3',5'-di-O-p-toluoyl-β-L-erythro-pentofuranosyl)pyrazole-4-carboxylate (99)

To a solution of methyl pyrazole-4-carboxylate (315 mg, 2.5 mmol) in dry acetonitrile (30 mL) was added sodium hydride (60% in oil, 144 mg, 3.0 mmol). The mixture was stirred at 50°C for 15 min. Chlorocarbon 13 (1 g, ∼95%, 2.5 mmol) was added and the suspension was stirred at room temperature for 2 h. The mixture was evaporated to give a residue which was partitioned between water and EtOAc. The aqueous solution was extracted with EtOAc. The combined EtOAc extract was washed with water and brine, dried over Na2SO4 and evaporated to dryness. The residue was purified on a silica gel column (3×12 cm) using hexane/EtOAc (4:1) to give 99 as a crystalline powder (549 mg, 46%).

1H NMR (CDCl3): δ 2.40 (d, 6H, aromatic-CH3), 2.72 (m, 1H, H2.), 3.16 (m, 1H, H2.), 3.79 (d, 3H, OCH3), 4.51-4.62 (m, 3H, H4. & H5.), 5.77 (m, 1H, H3.), 6.20 (t, 1H, H1.), 7.24 (m, 4H, aromatic-H), 7.92 (m, 5H, aromatic -H & C5H), 8.10 (s, 1H, C3H).

Example 78

1-(2'-deoxy-β-L-erythro-pentofuranosyl)pyrazole-4-carboxamide (100)

A mixture of 99 (500 mg, 1,046 mmol) and a saturated solution of methanolic ammonia (30 mL) was heated in a steel autoclave at 100°C for 16 h. After cooling, the solution was evaporated and the residue was purified on a silica gel column using CH 2 Cl 2 /MeOH (10:1) to give 100 as a yellow foam (50 mg, 20%).

1H NMR (DMSO-d6): δ 2.30 (m, 1H, H2.), 2.56 (m, 1H, H2.), 3.41-3.56 (m, 2H, H5.), 3.84 (m, 1H, H4.) , 4.36 (m, 1H, H3.), 4.88 (bs, 1H, OH), 5.32 (bs, 1H, OH), 6.11 (t, 1H, H1.), 7.08 (s, 1H, NH), 7.63 ( s, 1H, NH), ), 7.90 (d, 1H, C5H), 8.36 (d, 1H, C3H), 7.80 (s, 1H, NH), 8.19 (s, 1H, NH).

Example 79

Methyl-α-L-lyxopyranoside (102)

L-lyxose (101, 118 g, 786 mmol) was added to a methanol solution of HCl (600 mL, 0.5% w/v, prepared in situ by the reaction of acetyl chloride (6.0 mL)) and refluxed for 5 h [the reaction ended after 4 h (TLC 30% MeOH/CH2Cl2) and continued for a further 1 h (total 5 h)] with moisture excluded (CaCl2 protective tube).The reaction mixture was neutralized with pretreated Amberlite base resin IRA 410 (100.0 g) for 10 min with stirring. The resin was filtered and washed with methanol (3×50 mL). The combined washings were evaporated to give a colorless syrup. The syrup was co-evaporated with ethyl acetate (2×50 mL) and finally recrystallized (by melting the side of the flask or by sonication) from ethyl acetate ( 500 mL) to give white crystalline product 102 (87 g, 67% total from yield 1 and 2).

1H NMR (300 MHz, (CD3)2CO): δ 3.15 (bs, 3H, OH), 3.41 (s, 3H, OCH3), 3.48 (m, 1H), 3.66-3.72 (m, 2H), 3.73-3.87 (m, 2H), 4.64 (d, 1H, H5., J= 2.7 Hz).

Example 80

Methyl-2,3-O-isopropylidene-α-L-lyxopyranoside (103)

A solution of (4M) HCl in dioxane (4.0 mL) was added to a suspension of 102 (69 g, 420.0 mmol) in a mixture of 2,2-dimethoxypropane (200.0 mL) and anhydrous acetone (200.0 mL) and the reaction mixture was stirred at 25°C. during 16 h. TLC (50% ethyl acetate/CH2Cl2) of the reaction mixture showed complete conversion of the starting material. The reaction was quenched with solid sodium bicarbonate (500 mg) and the mixture was filtered. The filtrate was evaporated and the resulting oily residue (pink) was purified by flash chromatography on silica gel using CH2Cl2/ethyl acetate (100/0 to 80/20, in 5% steps) as eluent to give product 103 (80 g, 93.2 %). ).

1H NMR (300 MHz, CDCl3): δ 1.31 (s, 3H), 1.47 (s, 3H), 2.95 (bs, 1H), 3.41 (s, 3H), 3.66-3.77 (m, 3H), 4.07 (dd , 1H, J= 6.04 & 2.75 Hz), 4.16 (t, 1 H, J= 6.04 & 4.67 Hz), 4.60 (d, 1H, J = 2.74 Hz).

Example 81

Methyl-4-azido-4-deoxy-2, 3-O-isopropylidene-β-D-ribopyranoside (104)

To a mixture of pyridine (6.4 mL, 79.65 mmol) and dimethylamino pyridine (100 mg, 0.72 mmol) in anhydrous CH2Cl2 (400 mL) was slowly added trifluoromethanesulfonic anhydride (11.82 mL, 71.68 mmol) at -20°C. The mixture was stirred at -20°C for 5 min and then a solution of 103 (5.0 g, 24.50 mmol) in CH2Cl2 (50.0 mL) was added. The reaction mixture was stirred at -20°C for 15 min. It was then placed in an ice-water mixture (500 mL) and the organic layer was separated. The aqueous phase was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with brine (500 mL), dried (Na 2 SO 4 ) and evaporated to give the product as a pale yellow gummy solid (14 g).

Sodium azide (30.0 g, 461.53 mmol, 18.83 eq) at 0-5°C (ice-water bath) and was stirred at 23°C for 3 h. The volatiles were evaporated and the residue was diluted with CH 2 Cl 2 (500 mL) and water (200 mL). The organic layer was separated and washed with water (2×250 mL) and brine (300 mL), dried (Na2SO4) and evaporated to give an oily residue which was purified by flash chromatography hexane/ethyl acetate (100/0; 97.5/2.5). ; and 95/5) as eluent to give product 104 (2.8 g, 49.88% for two steps).

1H NMR (300 MHz, CDCl3): δ 1.36 (s, 3H, CH3), 1.54 (s, 3H, CH3), 3.42 (s, 3H, OCH3), 3.7-3.9 (m, 3H), 4.01 (dd, 1 H, J = 6.05 & 3.85 Hz), 4.48 (d, 1 H, J = 3.85 Hz), 4.51 (m, 1H).

Example 82

N-Acetyl-4-amino-4-deoxy-2, 3-O-isopropylidene-β-D-methyl-ribopyranoside (105)

To a solution of 104 (6.5 g, 28.38 mmol) in MeOH (50.0 mL) was added NaHCO3 (2.38 g, 28.38 mmol) followed by Pd/C (5% w/w, 650 mg). The reaction mixture was shaken under a hydrogen atmosphere (40 psi) at room temperature for 1 h. TLC (30% ethyl acetate/hexane) showed completion of the reaction. The reaction mixture was filtered through a celite pad and the filtrate was evaporated to dryness. The residues were co-evaporated with toluene (2×20 mL) and pyridine (2×20 mL). The obtained residues were used for the next reaction without further purification. To a mixture of the above residues (5.76 g, crude from the above reaction) and DMAP 20 (0.059 g, 0.425 mmol) in pyridine (6.8 mL, 84.5 mmol) was added acetic anhydride (4.01 mL, 42.57 mmol) at 0°C. The reaction mixture was stirred at room temperature for 2 h. TLC (100% ethyl acetate) showed completion of the reaction. MeOH (1.0 mL) was added and the volatiles were evaporated. The residue was dissolved in CH2Cl2 (300 mL) and this solution was then washed with cold and dilute HCl (0.5M, 3×200 mL), saturated NaHCO3 solution (200 mL) and brine (200 mL), dried (Na2SO4) and evaporated. . The residues thus obtained were purified by flash chromatography on silica gel using ethyl acetate/hexane (0/100 to 10/90 to 20/80 to 50/50 to 100/0) as eluent to obtain product 105 (total yield 3.76 g , 54.11%).

1H NMR (300 MHz, CDCl3): δ 1.35 (s, 3H, CH3), 1.51 (s, 3H, CH3), 2.0 (s, 3H, COCH3), 3.37 (t, 1H), 3.45 (s, 3H, OCH3), 3.85 (dd, 1H), 4.05 (dd, 1H), 4.38 (dd, 1H), 4.40 (d, 1H, J=4.5 Hz), 4.5 8 (m, 1H), 5.78 (bd, 1H) .

Example 83

1,2,3,5-tetra-O-acetyl-4-deoxy-4-(acetamido)-D-ribofuranose (106)

A solution of 105 (5.0 g, 20.40 mmol) in a mixture of distilled water and AcOH (1 : 1, 50 mL) was heated at 70-75°C for 1.5 h. TLC (100% ethyl acetate) showed completion of the reaction. Absolute EtOH (2×30 mL) was added and evaporated with volatiles to give a solid residue. A mixture of glacial acetic acid and acetic anhydride (50 mL, 1:1) was added to this solid and it was cooled to 0°C, treated with conc. H 2 SO 4 (1.5 mL). The reaction mixture was stirred at 0°C for 30 min and kept at 4°C for 2 days. The reaction mixture was treated with anhydrous NaOAc (15.0 g) and stirred at room temperature for 30 min. The reaction mixture was placed in an ice-water mixture (300 mL) and extracted with CH2Cl2 (2×250 mL). The combined organic layer was washed with water (2×250 mL) and brine (400 mL), dried (Na2SO4) and evaporated. The crude residue thus obtained was purified by flash chromatography on silica gel using MeOH/CH2Cl2 (0/100 to 3/97) as eluent to give pure product 106 (3.71 g, 50.82%).

1H NMR (300 MHz, CDCl3): δ 1.99-2.11 (m, 15H, 5×CH3), 4.17-4.5 (m, 3H), 5.27-5.52 (m, 2H), 6.35 (s, 0.75H), 6.53 (d, 0.25H, J= 4.8 Hz).

Example 84

Methyl-1-(2',3',5'-tri-O-acetyl-4'-deoxy-4'-acetamido-β-D-ribofuranosyl)-1,2,4-triazole-3-carboxylate (107 )

A suspension of methyl-1,2,4-triazole-3-carboxylate (1.77 g, 13.97 mmol) and ammonium sulfate (177 mg) in hexamethyldisilazane (40 mL) was refluxed for 2.5 h under N2 atmosphere. The reaction mixture was evaporated to dryness and the residue was suspended in 1,2-dichloroethane (50 mL). These were then treated with a solution of 106 (4.4 g, 12.25 mmol) in 1,2-dichloroethane (50 mL). Fuming SnCl4 (1.63 mL, 13.97 mmol) was then added to the reaction mixture at 0-5°C (ice-water bath) and stirred at room temperature for 1 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g) and washed with CH2Cl2 (100 mL). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude residue thus obtained was recrystallized from ethyl acetate (40 mL) to give the pure title product 107 (2.7 g, 51.71 %).

1H NMR (300 MHz, CDCl3): δ 2.03-2.15 (m, 12H, 4×COCH3), 3.95 (s, 3H, OCH3), 4.2 (m, 1H, H5.), 4.43 (m, 2H, H4. & H5.), 5.65 (dd, 1H, H3., J = 4.67 & 1.1 Hz), 6.17 (t, 1H, H2., J= 4.67 & 6.04 Hz), 6.28 (d, 1H, H1., J= 6.04 Hz), 8.47 (s, 0.86H, major rotamer, C6H), 8.60 (s, 0.14H, minor rotamer, C6H).

Analysis - calculated for C17H22N4O9: C, 47.89; H, 5.20; N. 13.14. Found: C, 47.93; H, 5.40; N, 13.27.

Example 85

1-(4'-deoxy-4'-acetamido-β-D-ribofuranosyl)-1,2,4-triazole-3-carboxamide (108)

A solution of 107 (2.7 g, 6.33 mmol) in saturated methanolic ammonia (100 mL) was stirred at room temperature in a steel autoclave for 16 h. The reaction mixture was evaporated to dryness and the resulting residue was purified by flash chromatography on alumina using a solvent mixture of ethyl acetate/n-propyl alcohol/water (64/4/32 to 57/14/29%, lower layer) as eluent to obtained the title compound 108 (1.7 g). The product is moistened with ~5% ethyl alcohol and also slightly contaminated with acetamide.

1H NMR (300 MHz, CD3OD): δ 1.87 (s, 0.86H, COCH3, minor rotamer (min)), 2.14 (s, 2.14H, COCH3, major rotamer (maj)), 3.87 (d, 2H, H5. , J= 6.59 Hz), 4.1-4.01 (m, 1H, H4.), 4.26 (d, 0.75H, J= 4.12 Hz, H3., May), 4.31 (t, 0.25H, J= 3.8 Hz, H3 ., min), 4.54 (t, 0.25H, J=4.1 Hz, H2., min), 4.85 (dd, 0.75H, J= 4.4 & 6.05 Hz, H2., maj), 6.03 (d, 0.75H, J= 6.04 Hz, H1., May), 6.81 (d, 0.25H, J= 4.13 Hz, H1., min), 8.69 (s, 0.75H, C5H, May), 8.95 (s, 0.25H, C5H, min).

Analysis - calculated for C10H15N5O5: C, 42.10; H, 5.30; N. 24.55. Found: C, 42.21; H, 5.19; N, 24.23.

Example 86

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido-β-D-ribofuranosyl]-1,2 ,4-triazole-3-carboxamide (109)

A suspension of 108 (0.7 g, 2.45 mmol) in pyridine (15 mL) was treated with 1,3-dichloro-1,1,3,3-tetraisopropyl-disiloxane (1.06 mL, 3.31 mmol) and stirred at room temperature for 16 h. . The reaction mixture was carefully quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The crude residue was purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 - 98/2 - 95/5 - 90/10) as eluent to give 109 (0.7 g, 54%).

1H NMR (300 MHz, CDCl3): δ 0.93-1.18 (m, 24H), 1.38 (m, 2H), 2.02 (s, 0.84H, COCH3, minor rotamer (min)), 2.15 (s, 2.16H, COCH3 , larger rotamer (maj)), 3.83 (m, 1H, H5.), 3.98-4.13 (m, 1H, H5.), 4.33 (d, 0.34H, J= 3.85 Hz, H2., min), 4.42 ( d, 0.66H, J= 4.67 Hz, H2., maj), 4.52 (dd, 0.34H, H4., min), 4.65 (dd, 0.66H, H4., maj), 5.29 (t, 1H, J= 4.97 Hz, H3.), 5.80 (bs, 0.66H, maj), 5.94 (bs, 0.34H, min), 5.99 (s, 0.34H, H1., min), 6.40 (s, 0.66H, H1., maj), 6.91 (bs, 0.66H, maj), 7.01 (bs, 0.34H, min), 8.37 (s, 0.66H, C5H, maj), 8.53 (s, 0.34H, C5H, min).

Example 87

1-[2'-O-(p-tolylthionoformyl)-3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido- β-D

-ribofuranosyl]-1,2,4-triazole-3-carboxamide (110)

O-(p-tolyl)thiochloroformate (0.219 mL, 1.42 mmol) was added to a solution of 109 (0.6 g, 1.138 mmol) in a mixture of CH2Cl2 (9 mL) and pyridine (1 mL) and the reaction mixture was stirred at room temperature for 16 h . The reaction mixture was quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and the organic layer was extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The crude residue was purified by flash chromatography on silica gel using CHCl3/ethyl acetate (100/0 - 95/5 - 90/10) as eluent to give pure product 110 (0.35 g, 45%).

1H NMR (300 MHz, CDCl3): δ 1.04-1.15 (m, 24H), 1.32 (m, 2H), 2.01 (s, 1H, COCH3, minor rotamer (min)), 2.19 (s, 2H, COCH3, major rotamer (maj)), 2.35 (s, 3H, CH3), 3.92 (m, 1H, H5.), 4.05 (m, 1H, H5.), 4.68-4.81 (m, 1H, H4.), 5.5 (t , 1H, J=6.05 & 5.22 Hz, H3.), 5.75 (bs, 0.66H, maj), 5.88 (bs, 0.34H, min), 6.10 (d, 1H, J=4.67 Hz, H2.), 6.17 (s, 0.34H, H1., min), 6.54 (s, 0.66H, H1., maj), 6.87 (bs, 0.66H, maj), 6.96 (d, 2H, J= 8.24 Hz, aromatic-H) , 6.98 (bs, 0.34H, min), 7.20 (d, 2H, J= 8.24 Hz), 8.40 (s, 0.66H, C5H, maj), 8.68 (s, 0.34H, C5H, min).

Example 88

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-2',4'-dideoxy-4'-acetamido-β-D-ribofuranosyl]- 1,2,4-triazole-3

-carboxamide (111)

A solution of 110 (0.35 g, 0.516 mmol) in toluene (20 mL) was flushed with argon for 20 min and then treated with 2,2'-azobisisobutyronitrile (0.084 g, 0.516 mmol) and tributyltin hydride (0.274 mL, 1.03 mmol). The reaction mixture was refluxed for 3 h in a stream of argon. The reaction mixture was purified by flash chromatography on silica gel using CHCl3/ethyl acetate (100/0 - 90/10 - 70/30 - 40/60 - 20/80 -0/100) as eluent to give product 111 ( 0.23 g, 87 %).

1H NMR (300 MHz, CDCl3): δ 0.95-1.15 (m, 24H), 1.24 (m, 2H), 2.0 (s, 0.9H, COCH3, minor rotamer (min)), 2.13 (s, 2.1H, COCH3) , larger rotamer (maj)), 2.36-2.58 (m, 1H, H2.), 2.84 (m, 1H, H2.), 3.74-3.92 (m, 2H, H5.), 4.11 (m, 0.66H, H4 ., maj), 4.49-4.67 (m, 0.34H, H4., min), 5.3 (m, 1H, H3.), 5.88 (bs, 0.66H, maj), 6.01 (bs, 0.34H, min), 6.14 (d, 0.34H, J=6.02 Hz, H1., min), 6.54 (d, 0.66H, J= 7.97 Hz, H1., May), 6.89 (bs, 0.66H, May), 7.03 (bs, 0.34H, min), 8.35 (s, 0.66H, C5H, May), 8.55 (s, 0.34H, C5H, min).

Example 89

1-(2',4'-dideoxy-4'-acetamido-β-D-ribofuranosyl)-1,2,4-triazole-3-carboxamide (112)

A solution of 111 (0.23 g, 0.45 mmol) in CH2Cl2 (5 mL) was treated with triethylamine trihydrofluoride (0.29 mL, 1.79 mmol) at room temperature. The reaction mixture was stirred for 48 h at room temperature. The volatiles were removed and the residue was purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 -95/5 - 90/10) as eluent to give pure product 112 (0.08 g, 66%).

1H NMR(300 MHz, CD3OD): δ 1.95 (s, 0.36H, COCH3, minor rotamer (min)), 2.16 (s, 2.64H, CH3, major rotamer (maj)), 2.51 (m, 1 H, H2 .), 2.87 (m, 1 H, H2.), 3.82 (m, 2H, H5.), 3.99 (t, 1H, J=6.87 Hz, H4.), 4.44 (d, 1H, J=4.12 Hz, H3.), 6.54 (t, 1H, J=7.69 Hz, H1.), 8.63 (s, 0.88H, C5H, maj), 8.88 (s, 0.12H, C5H, min).

Analysis - calculated for C10H15N5O4: C, 44.60; H, 5.62; N, 26.01. Found: C, 44.71; H, 5.69; N, 25.98.

Example 90

Methyl-2, 3-O-isopropylidene-α-D-lyxopyranoside (115)

D-lyxose (113, 100 g, 666.66 mmol) was added to a methanolic HCl solution [500 mL, 0.5% w/v, prepared in situ by reacting acetyl chloride (5 mL, 70.37 mmol) with MeOH (Fisher HPLC grade)] and refluxed for 5 h in an N2 atmosphere. The reaction mixture was neutralized with pretreated IRA-410 base resin (100.0 g) for 10 min with stirring. The resin was filtered and washed with methanol (3×125 mL). The combined washings were evaporated to give a faintly colored syrup of methyl-(3-D-lyxopyranoside) (114, 110 g, quantitative yield) which was saved for the next reaction without further purification.

Note:

Preparation of pre-treated Amberlite resin IRA-410: The resin (100g) was treated with aqueous NaOH solution (0.5M, 200mL) for 15 min. With stirring, it was filtered and rinsed with deionized water (4×300 mL) until the pH of the rinse showed a neutral pH. Finally, the resin was washed with anhydrous MeOH (3×30 mL) and immediately heated.

A solution of (4M) HCl in dioxane (8.0 mL) was added to a suspension of 114 (110 g, 666.66 mmol) in a mixture of 2,2-dimethoxypropane (400.0 mL) and anhydrous acetone (400.0 mL) and the reaction mixture was stirred at 25°C. during 16 h. TLC (50% ethyl acetate/CH2Cl2) showed completion of the reaction. The reaction was quenched with solid sodium bicarbonate (500 mg) and filtered. The filtrate was evaporated and the oily residue (pink) was purified by flash chromatography on silica gel using CH2Cl2/ethyl acetate (100/0 to 80/20, in 5% steps) as eluent to give 115 (63.97%, 87 g , total yield for both stages).

Example 91

Methyl-4-azido-4-deoxy-2, 3-O-isopropylidene-β-L-ribopyranoside (116)

To a mixture of pyridine (6.432 mL, 79.9 mmol) and dimethylamino pyridine (105 mg, 0.75 mmol) in anhydrous CH2Cl2 (600 mL) was slowly added trifluoromethanesulfonic anhydride (10.72 mL, 65 mmol) at -20°C. The mixture was stirred at -20°C for 5 min and a solution of 115 (10.2 g, 50 mmol) in CH2Cl2 (100.0 mL) was added, and the reaction mixture was stirred at -20°C for 15 min. TLC (15% ethyl acetate/hexane) showed completion of the reaction. The reaction mixture was poured into an ice-water mixture (500 mL) and the organic layer was separated. The aqueous phase was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×250 mL) and brine (500 mL), dried (Na2SO4) and evaporated to give the intermediate triflate product as a pale yellow gummy solid (16 g).

A solution of the above methyl-4-O-trifluoromethanesulfonyl-2,3-O-isopropylidene-β-D-lyxopyranoside (16 g) in DMF (300 mL) was cooled to 0°C. Lithium azide (12.5 g, 255.6 mmol) was added and stirred at 23°C for 3 h. The reaction mixture was diluted with toluene (200 mL) and the volatiles were evaporated. The residues were dissolved in a mixture of CH2Cl2 (500 mL) and water (200 mL). The organic layer was separated and washed with water (2×250 mL), brine (300 mL), dried (Na2SO4) and evaporated to give an oily residue which after purification by flash chromatography on silica gel using hexane/ethyl acetate (100 /0; 97.5/2.5; and 95/5) as eluent to give the pure azido product 116 (5.74 g, 50.2%).

1H NMR (300 MHz, (CDCl3): δ 1.38 (s, 3H, CH3), 1.55 (s, 3H, CH3), 3.44 (s, 3H, OCH3), 3.7-3.9 (m, 3H), 4.03 (dd , 1H, J= 6.32 & 3.85 Hz), 4.49 (d, 1H, J=3.84 Hz), 4.52 (m, 1H).

Example 92

N-acetyl-4-amino-4-deoxy-2, 3-O-isopropylidene-β-L-methyl-ribopyranoside (117)

To a solution of 116 (12.1 g, 52.83 mmol) in MeOH (40.0 mL) was added Pd/C (5% w/w, 1.2 g) and the reaction mixture was shaken under hydrogen (50 psi) at room temperature for 1 h. TLC (30% ethyl acetate/hexane) showed completion of the reaction. The reaction mixture was filtered through a pad of celite and the filtrate was evaporated to dryness and co-evaporated with toluene (2×50 mL) and pyridine (2×25 mL). The residues were used for the next reaction without further purification.

To the above crude mixture was added DMAP (0.7g, 5.0 mmol), pyridine (25.0 mL, 310.55 mmol) in CH2Cl2 (250.0 mL) and then acetic anhydride (25.0 mL, 265.0 mmol) at -5°C (ice-acetone bath). . After the addition, the cold bath was removed and the reaction mixture was stirred for 16 h. TLC (100% ethyl acetate) showed completion of the reaction. MeOH (10.0 mL) was added and the volatiles were evaporated. The residue was dissolved in CH2Cl2 (300 mL) and this solution was then washed with water (2×200 mL) and brine (200 mL), dried (Na2SO4) and evaporated. The residues were purified by flash chromatography using ethyl acetate/hexane (5/95 to 20/80 to 60/40 to 80/20) as eluent to give product 117 (total yield 11.49 g, 88.83%).

1H NMR (300 MHz, (CDCl3): δ 1.34 (s, 3H, CH3), 1.51 (s, 3H, CH3), 1.99 (s, 3H, COCH3), 3.37 (t, 1H), 3.83 (dd, 1H , J=5.77 & 5.49 Hz), 4.01 (t, 1H, J=5.77 & 4.67 Hz), 4.35 (t, 1H, J= 5.5 & 4.67 Hz), 4.40 (d, 1H, J=4.4 Hz), 4.54 (m, 1H), 5.76 (bd, 1H, J=7.97 Hz).

Example 93

1,2,3,5-tetra-O-acetyl-4-deoxy-4-(acetamido)-L-ribofuranose (118)

A solution of 117 (8.9 g) in a mixture of distilled water and AcOH (1:1, 100 mL) was heated to 70-75°C for 1.5 h. TLC (100% ethyl acetate) showed completion of the reaction. Absolute EtOH (2×50 mL) was added and evaporated together to give a dry solid residue. A mixture of glacial acetic acid and acetic anhydride (100.0 mL, 1:1) was added to this solid, cooled to 0°C (ice-water bath), and treated with conc. H 2 SO 4 (1.0 mL). The reaction mixture was stirred at 0°C for 30 min and kept at 4°C for 2 days. The reaction mixture was treated with anhydrous NaOAc (10.0 g) and stirred at room temperature for 30 min. The reaction mixture was then poured into a mixture of ice and water (400 mL) and extracted with CH2Cl2 (2×250 mL). The combined organic layer was washed with water (2×500 mL) and brine (400 mL), dried (Na2SO4) and evaporated. The crude product thus obtained was purified by flash chromatography using ethyl acetate/hexane (25/75 to 50/50) as eluent to give 118 (6.6 g, 50.67%).

1H NMR (300 MHz, (CDCl3): δ 2.0-2.12 (m, 15H, 5×COCH3), 4.18-4.51 (m, 3H), 5.33-5.36 (m, 1H), 5.45-5.55 (m, 1H) , 6.36 (s, 0.75H), 6.55 (d, 0.25H, J=5.22 Hz).

Example 94

Methyl-1-(2',3',5'-triacetyl-4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-1,2,4-triazole-3-carboxylate (119)

A suspension of methyl-1,2,4-triazole-3-carboxylate (1.022 g, 8.05 mmol) and ammonium sulfate (100 mg) in hexamethyldisilazane (20 mL) was refluxed for 2.5 h under N2 atmosphere. The volatiles were evaporated and the residue was suspended in 1,2-dichloroethane (50 mL). They were then treated with a solution of 118 (2,513 g, 7 mmol) in 1,2-dichloroethane (50 mL). Fuming SnCl4 (0.94 mL, 8.05 mmol) was then added to the reaction mixture at 0-5°C (ice-water bath). The reaction mixture was stirred at room temperature for 1 h. The reaction was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g) and washed with CH2Cl2 (100 mL). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude residue was recrystallized from ethyl acetate (40 mL) to give the title product 119 (1.8 g, 60.36%).

1H NMR (300 MHz, CDCl3): δ 2.03-2.14 (m, 12H, 4×COCH3), 3.93 (s, 3H, OCH3), 4.2 (m, 1H, H5.), 4.41 (m, 2H, H4. & H5.), 5.64 (d, 1H, H3., J= 4.67 Hz), 6.16 (t, 1H, H2., J= 4.95 & 5.77 Hz), 6.27 (d, 1H, H1., J= 6.05 Hz ), 8.46 (s, 0.86H, major rotamer, C6H), 8.60 (s, 0.14H, minor rotamer, C6H).

Analysis - calculated for C17H22N4O9: C, 47.89; H, 5.20; N. 13.14. Found: C, 47.77; H, 5.49; N, 13.04.

Example 95

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-1,2,4-triazole-3-carboxamide (120)

A solution of 119 (3.26 g, 7.65 mmol) in saturated methanolic ammonia (100 mL) was stirred at room temperature for 16 h. The reaction mixture was evaporated to dryness and the residue flash chromatographed on alumina using a solvent mixture of ethyl acetate/n-propyl alcohol/water (bottom layer, 64/4/32 to 57/14/29 %) to give the title product 120 (1.7 g, 77.98%). 1H NMR (300 MHz, (DMSO-d6 + D2O): δ 1.64 (s, 0.75H, COCH3, minor rotamer (min)), 2.0 (s, 2.25H, COCH3 major rotamer (maj)), 3.84-3.54 ( m, 3H, H4. & H5.), 4.1 (m, 1H, H3.), 4.32 (t, 0.25H, J=4.4 Hz, H2., min), 4.56 (t, 0.75H, J=4.2 Hz , H2., May), 5.82 (d, 0.75H, J=6.32 Hz, H1., May), 6.01 (d, 0.25H, J=4.4 Hz, H1., min), 8.74 (s, 0.75H, C5H, maj), 8.96 (s, 0.25H, C5H, min).

Analysis - calculated for C10H15N5O5: C, 42.10; H, 5.30; N. 24.55. Found: C, 42.44; H, 5.49; N, 24.69.

Example 96

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido-β-L-ribofuranosyl]-1,2 ,4-triazole-3

-carboxamide (121 )

A suspension of 120 (0.75 g, 2.63 mmol) in pyridine (15 mL) was treated with 1,3-dichloro-1,1,3,3-tetraisopropyl-disiloxane (1.09 mL, 3.42 mmol) and stirred at room temperature for 16 h . The reaction mixture was carefully quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The crude residues thus obtained were purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 - 98/2 - 95/5 - 90/10) as eluent to give product 121 (0.75 g, 54%).

1H NMR (300 MHz, CDCl3): δ 0.93-1.17 (m, 24H), 1.37 (m, 2H), 2.01 (s, 1H, COCH3, minor rotamer (min)), 2.14 (s, 2H, COCH3, major rotamer (Maj)), 2.98 (s, 0.34H, OH, exchangeable, min), 3.34 (s, 0.66H, OH, exchangeable, May), 3.78-3.84 (m, 1H, H5.), 3.97-4.14 ( m, 2H, H4. & H5.), 4.33 (d, 0.34H, J=4.12 Hz, H2., min), 4.41 (d, 0.66H, J= 4.95 Hz, H2., maj), 4.52 (m , H4., min), 4.65 (m, H3., min), 5.28 (t, J=4.95 Hz, H3., May), 5.80 (s, 0.66H, alternating, May), 5.95 (s, 0.34H , exchangeable, min), 5.97 (s, 0.34H, H1., min), 6.39 (s, 0.66H, H1., May), 6.89 (s, 0.66H, exchangeable, May), 7.00 (s, 0.34H , exchangeable, min), 8.37 (s, 0.66H, C5H, maj), 8.52 (s, 0.34H, C5H, min).

Example 97

1-[2'-O-(p-toluoylthionoformyl)-3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido- β-L

-ribofuranosyl]-1,2,4-triazole-3-carboxamide (122).

O-(p-tolyl)thiochloroformate (0.285 mL, 1.85 mmol) was added to a solution of 121 (0.65 g, 1.23 mmol) in a mixture of CH2Cl2 (9 mL) and pyridine (1 mL) and the reaction mixture was stirred at room temperature for 16 h . The reaction mixture was quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The thus obtained crude residues were purified by "flash" chromatography on silica gel using CHCl3/ethyl acetate (100/0 - 95/5 - 90/10) as eluent to obtain product 122 (0.33 g, 39.52%).

1H NMR (300 MHz, CDCl3): δ 0.92-1.15 (m, 24H), 1.29 (m, 2H), 2.01 (s, 1H, COCH3, minor rotamer (min)), 2.19 (s, 2H, COCH3, major rotamer (maj)), 2.35 (s, 3H, CH3), 3.92 (m, 1H, H5.), 4.07 (m, 2H, H4. & H5.), 4.68-4.8 (m, H3., min), 5.50 (m, H3., May), 5.7 (s, 0.66H, exchangeable, May), 5.82 (s, 0.34H, exchangeable, min), 6.10 (d, 1H, J=4.94 Hz, H2.), 6.17 (s, 0.34H, H1., min), 6.54 (s, 0.66H, H1., May), 6.70 (s, 0.34H, exchangeable, min), 6.86 (s, 0.66H, exchangeable, May), 6.96 (d, 2H, J=8.52 Hz, aromatic-H), 7.21 (d, 2H, J= 8.24 Hz aromatic-H), 8.40 (s, 0.66H, C5H, maj), 8.69 (s, 0.34H, C5H , min).

Example 98

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-2',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl]- 1,2,4-triazole-3

-carboxamide (123)

A solution of 122 (0.325 g, 0.48 mmol) in toluene (20 mL) was flushed with argon for 20 min. 2,2'-azobisisobutyronitrile (0.078 g, 0.48 mmol) and tributyltin hydride (0.25 mL, 0.96 mmol) were added to the solution. The reaction mixture was refluxed for 6 h under a stream of argon. The reaction mixture was evaporated to dryness and the crude product was purified by flash chromatography on silica gel using CHCl3/ethyl acetate (100/0 - 90/10 - 70/30 - 40/60 - 20/80 - 0/100) as eluent. to obtain 123 (0.22 g, 89.68 %).

1H NMR (300 MHz, CDCl3): δ 0.92-1.15 (m, 24H), 1.28 (m, 2H), 2.0 (s, 0.66H, COCH3, minor rotamer (min)), 2.13 (s, 2.34H, COCH3 , larger rotamer (maj)), 2.36-2.58 (m, 1H, H2.), 2.85 (dd, 1H, J=13.73 & 7.41 Hz, H2.), 3.74-4.09 (m, 3H, H4. & H5. ), 4.49-4.67 (m, H3., min), 5.30 (m, H3., May), 5.83 (s, 0.8H, exchangeable, May), 5.94 (s, 0.2H, exchangeable, min), 6.14 ( d, 0.2H, J=6.05 Hz, H1., min), 6.54 (d, 0.8H, J=8.24 Hz, H1., May), 6.89 (s, 0.8H, exchangeable, May), 7.04 (s, 0.2H, exchangeable, min), 8.35 (s, 0.8H, C5H, maj), 8.55 (s, 0.2H, C5H, min).

Example 99

1-(2',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl)-1,2,4-triazole-3-carboxamide (124)

A solution of 123 (0.2 g, 0.39 mmol) in CH2Cl2 (5 mL) was treated with triethylamine tris-hydrofluoride (0.25 mL, 1.56 mmol) at room temperature. The reaction mixture was stirred for 48 h and the volatiles were evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 - 95/5 - 90/10 - 85/15) as eluent to give 124 (0.08 g, 66%).

1H NMR (300 MHz, CD3OD): δ 1.95 (s, 0.36H, COCH3, minor rotamer (min)), 2.16 (s, 2.64H, COCH3, major rotamer (maj), 2.51 (m, 1H, H2.) , 2.87 (m, 1H, H2.), 3.82 (m, 2H, H5.), 3.99 (t, 1H, J=6.87 Hz, H4.), 4.44 (d, 1H, J=4.12 Hz, H3.) , 6.54 (t, 1H, J=7.69 Hz, H1.), 8.63 (s, 0.88H, C5H, maj), 8.88 (s, 0.12H, C5H, min).

Analysis - calculated for C10H15N5O4: C, 44.60; H, 5.62; N, 26.01. Found: C, 44.69; H, 5.71; N, 26.10.

Example 100

1-(2',3',5'-tri-O-acetyl-4'-deoxy-4'-acetamido-β-L-ribofuranosyl)thymine (125)

A suspension of thymine (1.26 g, 10 mmol) and ammonium sulfate (126 mg) in hexamethyldisilazane (25 mL) was refluxed for 5 h in an N2 atmosphere. The reaction mixture was evaporated to dryness and the residue was suspended in 1,2-dichloroethane (50 mL). A solution of 118 (2.513 g, 7 mmol) in 1,2-dichloroethane (50 mL) was added followed by fuming SnCl4 (1.17 mL, 10 mmol, 1.42 eq.) at 0-5°C (ice-water bath). The reaction mixture was stirred at room temperature for 1 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g) and washed with CH2Cl2 (100 mL). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The residues thus obtained were purified by flash chromatography on silica gel using CHCl3/acetone (95/5 - 90/10 - 85/15 - 80/20) as eluent to give pure title compound 125 (2.9 g, quantitative).

1H NMR (300 MHz, CDCl3): δ 1.89-2.2 (m, 15H, 4×COCH3 & C5CH3), 4.08 (m, 0.5H, H5.), 4.37-4.56 (m, 2.5H, H4. & H5. ), 5.32 (m, 0.5H, H3.), 5.47 (m, 1.5H, H2. & H3.), 6.15 (m, 0.5H, H1.), 6.37 (d, 0.5H, J=6.6 Hz, H1.), 7.16 (s, 0.5H, C6H), 7.44 (s, 0.5H, C6H), 9.02 (s, 0.5H, NH, exchangeable), 9.20 (s, 0.5H, NH, exchangeable).

Example 101

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)thymine (126)

A solution of 125 (3.1 g, 7.29 mmol) in saturated methanolic ammonia (100 mL) was stirred at room temperature in a steel autoclave for 16 h. The steel autoclave was cooled to 0°C, opened and evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (95/5 - 90/10 - 85/15) as eluent to give the title compound 126 (1.72, 78.86%).

1H NMR (300 MHz, (DMSO-d6 + D2O): δ 1.70 (s, 1.35H, COCH3, minor rotamer (min)), 1.73 (s, 1.35H, C5CH3), 1.77 (s, 1.65H, C5CH3) , 1.98 (s, 1.65H, COCH3, major rotamer (May), 3.95-3.57 (m, 4H, H3., H4. & H5.), 4.13 (t, 0.55H, J= 4.67 Hz, H2., May ), 4.20 (dd, 0.45H, J = 4.4 Hz, H2., min), 5.72 (d, 0.45H, J= 6.6 Hz, H1., min), 5.88 (d, 0.55H, J=5.77 Hz, H1., May), 7.68 (s, 0.45H, C6H, min), 8.00 (s, 0.55H, C6H, May).

Analysis - calculated for C12H17N3O6: C, 48.16; H, 5.73; N, 14.04. Found: C, 48.23; H, 5.81; N, 14.29.

Example 102

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido-β-L-ribofuranosyl]thymine (127) &

1-[(2',3'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-dideoxy-4'-acetamido-β-L-ribofuranosyl]thymine (128)

A suspension of 126 (1.72 g, 5.75 mmol) in pyridine (25 mL) was treated with 1,3-dichloro-1,1,3,3-tetraisopropyl-disiloxane (2.75 mL, 8.59 mmol) and stirred at room temperature for 16 h . The reaction mixture was carefully quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The crude residues were purified by flash chromatography on silica gel using hexane/ethyl acetate (90/10 - 80/20 - 60/40 - 20/80 - 0/100) as eluent to obtain a mixture of inseparable regioisomeric products 127 and 128 (2.15 g, 69%).

1H NMR (300 MHz, CDCl3): δ 1.0 (m), 1.9-2-2.13 (m), 3.79-4.13 (m), 4.3-4.47 (m), 4.74 (d), 5.07-5.21 (m), 5.47 (s), 5.84 (s), 5.93 (d, J=3.3 Hz), 7.20 (s), 7.40 (s), 7.53 (s), 7.78 (s), 8.88 (s), 9.13 (s), 9.67 (s).

Example 103

1-[2'-O-(p-tolylthionoformyl)-3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy-4'-acetamido- β-L-ribofuranosyl]

thymine (129 ) & 1-[5'-O-(p-tolylthionoformyl)-2',3'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-4'-deoxy- 4'-acetamido-β

-L-ribofuranosyl)thymine (130)

To a mixture of 127 and 128 (2 g, 3.69 mmol) in pyridine (20 mL) was added O-(p-toluoyl)thiochloroformate (0.712 mL, 4.43 mmol) and the reaction mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with saturated NaHCO3 solution (5 mL) and diluted with CH2Cl2 (100 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 (2×25 mL). The combined organic layer was washed with water (2×100 mL) and brine (100 mL), dried (Na2SO4) and evaporated. The crude residues were purified by flash chromatography on silica gel using hexane/ethyl acetate (90/10 - 80/20 - 70/30 - 40/60) as eluent to give the faster product (0.9 g) and the slower product (0.8 Mr). The total yield of both products was 1.7 g (66.54%). 1H NMR analysis of both products showed that the slower product is 129, while the faster product is 130:

129 1H NMR (300 MHz, CDCl3): δ 0.98-1.06 (m, 24H), 1.89 (s, 3H, CH3), 2.00 (s, 2H, COCH3, larger rotamer, (maj)), 2.25 (s, 1H , COCH3, minor rotamer, (min)), 2.34 (s, 3H, CH3), 3.85-4.03 (m, 2H, H5.), 4.38-4.80 (m, 2H, H3. & H4.), 5.3 (m , 0.24H, H2., min), 5.7 (m, 0.76H, H2., maj), 6.01 (s, 1H, H1.), 6.95 (d, 2H, J=8.52 Hz, aromatic-H), 7.20 (d, 2H, J=8.52 Hz, aromatic-H), 7.35 (s, 0.24H, C6H), 7.57 (s, 0.76H, C6H), 8.23 (bs, 0.24H, NH, exchangeable), 8.64 (s , 0.76H, NH, exchangeable).

130 1H NMR (300 MHz, CDCl3): δ 1.00-1.06 (m, 26H), 1.87 (s, 3H, CH3), 2.02 (s, 2.4H, COCH3, larger rotamer, (maj)), 2.22 (s, 0.6H, COCH3 , minor rotamer, (min)), 4.22-4.5 (m, 3H, H4. & H5.), 4.88 (m, 1H, H3.), 5.22 (m, 1H, H2.), 6.01 ( d, 1H, J=3.02 Hz, H1.), 6.94 (d, 2H, J=8.24 Hz, aromatic-H), 7.21 (d, 2H, J=8.52 Hz, aromatic-H), 7.78 (s, 1H , C6H), 8.38 (bs, 0.16H, NH, exchangeable, min), 8.44 (s, 0.84H, NH, exchangeable, maj).

Example 104

1-[(3',5'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-2',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl]thymine (131)

A solution of 129 (0.74 g, 1.070 mmol) in toluene (25 mL) was flushed with argon for 20 min. To this solution was added 2,2'-azobisisobutyronitrile (0.174 g, 1.074 mmol) followed by tributyltin hydride (0.56 mL, 2.113 mmol, 2 eq.). The reaction mixture was refluxed for 6 h in a stream of argon. The volatiles were evaporated and the crude residue was purified by flash chromatography on silica gel using hexane/ethyl acetate (100/0 90/10 - 80/20 - 70/30 - 60/40) as eluent to give 131 (0.45 g, 80.03 %).

1H NMR (300 MHz, CDCl3): δ 0.98-1.06 (m, 24H), 1.26 (m, 2H), 1.90 (s, 3H, CH3), 1.97 (s, 2.25H, COCH3, major rotamer, (may) ), 2.17 (s, 0.75H, COCH3 , minor rotamer, (min)), 2.2-2.4 (m, 1.5H, H2.), 2.65 (m, 0.5H, H2.), 3.67 (m, 1H, H5 .), 4.0 (m, 1H, H5.), 4.32 (m), 4.64 (m, 1H, H4.), 5.12 (m, 1H, H3.), 5.71 (m, O.15H, H1., min ), 6.05 (m, 0.85H, J= 6.05 Hz, H1., May), 7.33 (s, 0.15H, C6H, min), 7.53 (s, 0.85H, C6H, May), 8.23 (bs, 0.15H , NH, exchangeable, min), 8.76 (s, 0.85H, NH, exchangeable, maj).

Example 105

1-(2',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl)thymine (132)

A solution of 131 (0.38 g, 0.72 mmol) in CH2Cl2 (10 mL) was treated with triethylamine tris-hydrofluoride (0.585 mL, 3.6 mmol) at room temperature. The reaction mixture was stirred for 48 h and evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 - 97/3 - 94/6 - 90/10) as eluent to give the title compound 132 (0.19 g, 92.75%).

1H NMR (300 MHz, CD3OD): δ 1.83 (s, 1.35H, C5CH3), 1.86 (s, 1.65H, C5CH3), 1.95 (s, 1.35H, COCH3, minor rotamer (min)), 2.18 (s, 1.65H, COCH3, larger rotamer (maj)), 2.37 (m, 2H, H2.), 4.05-3.73 (m, 3H, H4. & H5.), 4.32 (d, 0.55H, J=3.85 Hz, H3 ., maj), 4.36 (bs, 0.45H, H3., min), 6.26 (t, 0.45H, J= 8.2 Hz, H1., min), 6.49 (t, 0.55H, J=7.4 Hz, H1. , May), 7.70 (s, 0.55H, C6H, May), 8.18 (s, 0.45H, C6H, min).

Analysis - calculated for C12H17N3O5⋅1/2H2O: C, 49.31; H, 6.21; N, 14.38. Found: C, 49.49; H, 6.43; N, 14.51.

Example 106

1-[(2',3'-O-(1,1,3,3-tetraisopropyl-1,3-disiloxanediyl)-5',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl]thymine (133)

A solution of 130 (1.35 g, 1.954 mmol) in toluene (40 mL) was flushed with argon for 20 min. To this solution was added 2,2'-azobisisobutyronitrile (0.32 g, 1.954 mmol) and tributyltin hydride (1.035 mL, 3.905 mmol). The reaction mixture was refluxed for 1.5 h in a stream of argon. The reaction mixture was evaporated to dryness. The crude residues were purified by "flash" chromatography on silica gel using hexane/ethyl acetate (100/0 - 90/10 - 80/20 - 70/30 - 60/40) as eluent to 133 (0.7 g, 68.24 %).

1H NMR (300 MHz, CDCl3): δ 0.98-1.05 (m, 24H), 1.24 (m, 2H), 1.46 (d, 1.2H, H5., minor rotamer (min), 1.52 (d, 2.8H, J =6.9 Hz, H5., larger rotamer (May), 1.89 (s, 1.2H, COCH3, min), 1.93 (s, 3H, CH3), 2.09 (s, 2.8H, COCH3, May), 3.86 (m, 0.6H, H4., maj), 3.98 (m, 0.4H, H4., min), 4.12-4.36 (m, 1H, H3.), 5.18 (m, 1H, H2.), 5.30 (d, 0.6H , J= 6.05 Hz, H1., maj), 5.98 (d, 0.4H, J= 3.57 Hz, H1., min), 6.99 (s, 0.4H, C6H, min), 7.08 (s, 0.6H, C6H , maj), 8.53 (bs, 0.6H, NH, exchangeable, maj), 8.66 (bs, 0.4H, NH, exchangeable, min).

Example 107

1-(5',4'-dideoxy-4'-acetamido-β-L-ribofuranosyl)thymine (134)

A solution of 133 (0.6 g, 1.14 mmol) in CH2Cl2 (20 mL) was treated with triethylamine tris-hydrofluoride (0.558 mL, 3.42 mmol) at room temperature. The reaction mixture was stirred at room temperature for 20 h and the volatiles were evaporated to dryness. The residues were purified by flash chromatography on silica gel using CHCl3/MeOH (100/0 - 97/3 - 94/6 - 90/10) as eluent to give 134 (0.2 g, 61.83%).

1H NMR (300 MHz, (CD3OD): δ 1.40 (d, 0.36H, J = 6.87 Hz, H5., minor rotamer (min)), 1.48 (d, 0.64H, J = 6.87 Hz, H5., major rotamer (May)), 1.87 (s, 1.08H, C5CH3), 1.91 (s, 1.92H, C5CH3), 1.91 (s, 1.08H, COCH3, min), 2.09 (s, 1.92H, COCH3, May), 3.84 -4.09 (m, 2H, H3. & H4.), 4.33 (m, 0.36H, H2., min), 4.67 (m, 0.64H, H2., maj), 5.71 (d, 0.64H, J=6.87 Hz, H1., May), 6.08 (d, 0.36H, J= 5.77 Hz, H1., min), 7.21 (s, 0.36H, C6H, min), 7.27 (s, 0.64H, C6H, May).

Analysis - calculated for C12H17N3O5: C, 50.88; H, 6.05; N, 14.83. Found: C, 50.91; H, 6.23; N, 14.91.

Example 108

1-(2',3',5'-O-triacetyl-4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-6-azauracil (135)

A suspension of 6-azauracil (0.909 g, 8.05 mmol) and ammonium sulfate (100 mg) in hexamethyldisilazane (20 mL) was refluxed for 2 h under N2 atmosphere. The volatiles were evaporated and the residue was suspended in 1,2-dichloroethane (50 mL). With stirring, a solution of 118 (2.513 g, 7 mmol) in 1,2-dichloroethane (50 mL) was added to the solution, followed by fuming SnCl4 (0.94 mL, 8.05 mmol, 1.15 eq.) at 0°C (water-ice bath). . The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude residue was purified by flash chromatography on silica gel using hexane/ethyl acetate (85/15 - 70/30 - 50/50 - 30/70 - 0/100) as eluent to give the title compound 135 (0.5 g, 17 %).

1H NMR (300 MHz, CDCl3): δ 2.01-2.15 (m, 12H), 4.12-4.48 (m, 3H, H4. & H5.), 5.47 (m, 1H, H3.), 5.57 (m, 0.2H , H2., minor rotamer (min)), 5.64 (m, 0.8H, H2., major rotamer (maj)), 6.41 (d, 0.2H, J=5.4 Hz, H1., min), 6.52 (d, 0.8H, J=7.2 Hz, H1., maj), 7.38 (d, 0.6H, J=2.1 Hz, C5H, maj), 7.54 (s, 0.4H, C5H, min), 9.22 (bs, 0.6H, NH, exchangeable, maj), 9.46 (bs, 0.4H, NH, exchangeable, min).

Example 109

1-(2',3',5'-O-triacetyl-4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-6-carbomethoxy-uracil (136)

A suspension of 6-carbomethoxyuracil (1.7 g, 10 mmol) and ammonium sulfate (170 mg) in hexamethyldisilazane (25 mL) was refluxed for 2 h under N2 atmosphere. The volatiles were evaporated and the residue was suspended in 1,2-dichloroethane (50 mL). With stirring, a solution of 118 (2.513 g, 7 mmol) in 1,2-dichloroethane (50 mL) was added to the solution, followed by fuming SnCl4 (1.17 mL, 10 mmol, 1.42 equiv.) at 0°C (water-ice bath) . The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude residue was purified by flash chromatography on silica gel using hexane/ethyl acetate (95/5 - 80/20 - 70/30 - 50/50) as eluent to give the title compound 136 (2.2 g, 67 %).

1H NMR (300 MHz, CDCl3): δ 1.99-2.10 (m, 12H), 3.92 (s, 2H, OCH3, major rotamer (maj)), 3.98 (s, 1H, OCH3, minor rotamer (min)), 4.00 -4.07 (m, 1H, H5.), 4.53 (m, 2H, H4. & H5.), 5.48 (d, 0.8H, J=4.67 Hz, H3., May), 5.53 (d, 0.2H, J =4.94 Hz, H3., min), 6.13 (m, 0.2H, H2., min), 6.20 (dd, 0.8H, J=4.67 & 7.96 Hz, H2., maj), 6.30 (s, 0.8H, H1., maj), 6.37 (s, 0.2H, H1., min), 6.58 (d, 0.2H, J=6.87 Hz, C5H, min), 6.68 (d, 0.8H, J=7.99 Hz, C5H, maj), 8.70 (bs, 0.8H, NH, exchangeable, maj), 8.89 (bs, 0.2H, NH, exchangeable, min).

Example 110

1-(2',3',5'-O-triacetyl-4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-5-fluorouracil (137)

A suspension of 5-fluorouracil (1.3 g, 10 mmol) and ammonium sulfate (130 mg) in hexamethyldisilazane (25 mL) was refluxed for 4 h under N2 atmosphere. The volatiles were evaporated and the residue was suspended in 1,2-dichloroethane (50 mL). With stirring, a solution of 118 (2.513 g, 7 mmol) in 1, 2-dichloroethane (50 mL) was added to the solution, followed by fuming SnCl4 (1.17 mL, 10 mmol, 1.42 equiv.) at 0°C (water-ice bath). . The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude product was purified by flash chromatography on silica gel using CHCl3/acetone (80/20) as eluent to give pure product 137 (1 g, 33.30 %).

1H NMR (300 MHz, CDCl3): δ 2.02-2.21 (m, 12H), 4.10 (m, 0.5H, H5.), 4.43-4.56 (m, 2.5H, H4. & H5.), 5.30 (m, 0.5H, H3.), 5.43-5.54 (m, 1.5H, H2. & H3.), 6.09 (t, 0.5H, J= 6.32 & 4.94 Hz, H1.), 6.28 (d, 0.5H, J= 4.94 Hz, H1.), 7.48 (d, 0.5H, J=5.77 Hz, C6H), 7.95 (d, 0.5H, J= 5.77 Hz, C6H), 9.19 (bs, 0.5H, NH, exchangeable), 9.34 (bs, 0.5H, NH, exchangeable).

Example 111

1-(2',3', 5'-O-triacetyl-4'-deoxy-4'-acetamido-β-L-ribo furanosyl)-5-fluorocytosine (138)

A suspension of 5-fluorocytosine (1.29 g, 10 mmol, 1.42 eq) and ammonium sulfate (322 mg) in hexamethyldisilazane (40 mL) was refluxed for 4 h under N2 atmosphere. The volatiles were evaporated and the residue was suspended in 1,2-dichloroethane (50 mL). With stirring, a solution of 118 (2.513 g, 7 mmol) in 1, 2-dichloroethane (50 mL) was added to the solution, followed by fuming SnCl4 (1.17 mL, 10 mmol, 1.42 equiv.) at 0°C (water-ice bath). . The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was carefully quenched with saturated NaHCO3 solution (50 mL) and diluted with CH2Cl2 (200 mL). The mixture was filtered through a pad of celite (5 g). The organic layer of the filtrate was separated and the aqueous layer was extracted with CH2Cl2 (2×100 mL). The combined organic layer was washed with water (2×300 mL) and brine (500 mL), dried (Na2SO4) and evaporated. The crude residue was purified by flash chromatography on silica gel using CHCl3/acetone (80/20) to give pure product 138 (1 g, 33.55 %).

1H NMR (300 MHz, CDCl3): δ 1.98-2.18 (m, 12H), 4.08 (m, 0.5H, H5.), 4.37-4.61 (m, 2.5H, H4. & H5.), 5.28 (m, 1H, H3.), 5.44 (t, 0.8H, J= 4.67 Hz, H2., major rotamer (maj)), 5.55 (d, 0.2H, J= 4.39 Hz, H2., minor rotamer (min)), 5.76 (bs, 1H, NH2, exchangeable), 6.27 (bt, 0.23H, H1., min), 6.37 (d, 0.77H, J=3.57 Hz, H1., maj), 7.49 (d, 0.23H, J =5.77 Hz, C6H, min), 7.79 (bs, 1H, NH2, exchangeable), 7.94 (d, 0.77H, J= 6.32 Hz, C6H, maj).

Example 112

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-6-azauracil (139)

A solution of 135 (0.45 g, 1.09 mmol) in saturated methanolic ammonia (10 mL) was stirred in a steel autoclave at room temperature for 16 h. The steel autoclave is cooled, opened and evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (95/5 - 90/10 - 85/15) as eluent to give the title compound 139 (0.18 g, 57.62%).

1H NMR (300 MHz, DMSO-d6): δ 1.84 (s, 1.35H, COCH3, minor rotamer (min)), 1.95 (s, 1.65H, COCH3, major rotamer (maj)), 3.46-3.85 (m, 3H, H4. & H5.), 4.01 (m, 1H, H3.), 4.22 (m, 1H, H2.), 4.89 (m, 0.45H, OH, min, exchangeable), 5.01 (m, 0.55H, OH, maj, exchangeable), ), 5.15 (s, 0.45H, OH, min, exchangeable), 5.28 (s, 0.55H, OH, maj, exchangeable), 5.39 (d, 0.45H, J=6.86 Hz, OH , min, exchangeable), 5.50 (d, 0.55H, J=5.7 Hz, OH, maj, exchangeable), 6.0 (d, 0.45H, J= 7.15 Hz, H1., min), 6.05 (d, 0.55H, J=5.5 Hz, H1., maj), 7.50 (s, 0.45H, C5H, min), 7.61 (s, 0.55H, C5H, maj), 12.2 (bs, 1H, NH, exchangeable).

Analysis - calculated for C10H14N4O6: C, 41.96; H, 4.93; N, 19.57. Found: C, 42.03; H, 5.11; N, 19.64.

Example 113

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)uracil-6-carboxamide (140)

A solution of 136 (2 g, 4.26 mmol) in saturated methanolic ammonia (20 mL) was stirred in a steel autoclave at room temperature for 16 h. The steel autoclave is cooled, opened and evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (95/5 - 90/10 - 85/15) as eluent to give the title compound 140 (1 g, 71.49%). 1H NMR (300 MHz, DMSO-d6 + D2O): δ 1.70 (s, 1H, COCH3, minor rotamer (min)), 1.89 (s, 2H, COCH3, major rotamer (maj)), 3.97-3.44 (m, 4H, H3., H4. & H5.), 4.73 (m, 1H, H2.), 6.26-6.08 (m, 2H, C5H & H1.).

Analysis - calculated for C12H16N4O7: C, 43.90; H, 4.91; N, 17.07. Found: C, 43.99; H, 5.06; N, 17.21.

Example 114

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-5-fluorouracil (141)

A solution of 137 (1 g, 2.33 mmol) in saturated methanolic ammonia (20 mL) was stirred in a steel autoclave at room temperature for 16 h. The steel autoclave was cooled to 0°C, opened and evaporated to dryness. The residues were purified by flash chromatography on silica gel using CHCl3/MeOH (95/5 - 90/10 - 85/15) as eluent to give the title compound 141, (0.6 g, 84.95%).

1H NMR (300 MHz, (DMSO-d6 + D2O): δ 1.72 (s, 1.35H, COCH3, minor rotamer (min)), 1.83 (s, 1.65H, COCH3, major rotamer (maj)), 3.35-4.18 (m, 5H, H2., H3., H4. & H5.), 5.74 (d, 0.45H, J=5.77 Hz, H1., min), 5.84 (d, 0.55H, J= 4.1 Hz, H1. , maj), 8.25 (s, 0.45H, C6H, min), 8.53 (s, 0.55H, C6H, maj), 11.77 (bs, 1H, NH, exchangeable).

Analysis - calculated for C11H14FN3O6: C, 43.57; H, 4.65; N, 13.86. Found: C, 43.40; H, 4.71; N, 13.80.

Example 115

1-(4'-deoxy-4'-acetamido-β-L-ribofuranosyl)-5-fluorocytosine (142)

A solution of 138 (1 g, 2.33 mmol) in saturated methanolic ammonia (20 mL) was stirred in a steel autoclave at room temperature for 16 h. The steel autoclave is cooled, opened and evaporated to dryness. The residue was purified by flash chromatography on silica gel using CHCl3/MeOH (95/5 - 90/10 - 85/15) as eluent to give the title compound 142 (0.64 g, 90.70%).

1H NMR (300 MHz, CD3OD): δ 1.92 (s, 2H, COCH3, major rotamer (maj)), 2.17 (s, 1H, COCH3, minor rotamer (min)), 3.75-3.93 (m, 2H, H5. ), 4.16-4.28 (m, 1.5H, H3. & H4.), 4.49 (t, 0.5H, J=4.4 & 4.94 Hz, H3.), 4.65 (s, 1H, H2.), 5.77 (d, 0.33H, J=5.22 Hz, H1., min), 6.11 (dd, 0.66H, J=1.92 & 4.12 Hz, H1., May), 8.19 (d, 0.33H, J= 6.86 Hz, C6H, min) , 8.66 (d, 0.66H, J = 7.15 Hz, C6H, May).

Analysis - calculated for C11H15FN4O5: C, 43.71; H, 5.00; N, 18.54. Found: C, 43.77; H, 5.17; N, 18.79.

It is understood that the embodiments described are illustrative only and modifications may be made by those skilled in the art. Accordingly, this invention should not be construed as limiting the embodiments shown, but is limited only by the scope of the appended claims.

Claims (15)

1. A compound having a structure according to formula I: [image] indicated by A is independently selected from N and C; B, C, E and F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamines, COCH 3 , lower alkyl alkenyl, lower alkyl vinyl or lower alkyl aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamines, lower alkyl alkenyl, lower alkyl vinyl, lower alkyl aryl or substituted heterocyclic compounds; D is independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2, P or none, where R1 is independently H, O, lower alkyl, lower alkylamines, COCH3, lower alkyl alkenyl , lower alkyl vinyl or lower alkyl aryl, and R 2 is independently H, OH, halogens, CN, N 3 , NH 2 , lower alkyl, lower alkylamines, lower alkyl alkenyl, lower alkyl vinyl, lower alkyl aryl or substituted heterocyclic compounds; X is independently O, S, CH 2 or NR; where R is COCH3; R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl and lower alkyl amines; R2, R3, R5, R6, R7 and R8 are independently selected from the group consisting of H, OH, CN, N3, halogens, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkyl amines and substituted heterocyclic compounds; and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are not all simultaneously substituted; so when R2 = R3 = H, then R7 and R8 are hydrogen or none; when R 1 , R 4 or R 5 are substituted, then R 7 = R 8 = H and R 2 = R 3 = OH; when R 2 or R 3 are substituted, then R 7 and R 8 are equal to H or OH; when R 7 or R 8 are substituted, then R 2 and R 3 are equal to H or OH; when R7 and R8 are hydroxyl, then R2 and R3 are not OH; when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is a CH or C-substituent; F = CH; X = O, S or CH2, then R2 will not be H, OH, CH3, halogen, N3, CN, SH, SPh, CH2OH, CH2OCH3, CH2SH, CH2F, CH2N3, aryl, aryloxy or heterocyclic; when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is CH, C-CH3 or halogen; F = CH; X = N-COCH3, then R2 will not be H or OH; when A = N; B = CH; C = CH or CH3; D = CH or C-CH3; E is CH, C-CH3 or C-CONH2; F = CH; X = O or CH2, then R2 will not be H or OH; when A = N; B = N, CO or CH; C = CH, C-Cl or C-OCH3; D = CH or C-Ph; E is CH, C-Cl or C-Ph; F = N or CO; X = O, then R 2 will not be H or OH; when A = N; B = CO or CS; C = N or NH; D = CO or C-NH2; E is CH or N; F = N or CH; X = O, then R 2 will not be H or OH; and when A = C; B = CH; C = NH; D = CO, CS or C-NH2; E is N or NH; F = CO or CH; X = O, then R 2 will not be H or OH. 2. Compound according to claim 1, characterized in that it has a structure according to formula III: [image] where: X is independently O, S, CH 2 and NR, where R is COCH 3 ; R' and R" are independently selected from H, CN, C(=O)NH2, NH2, C(=S)NH2, C(=NH)NH2⋅HCl, C(=NOH)NH2, C(=NH) OMe, heterocyclic compounds, halogen, lower alkyl or lower alkyl-aryl; R 2 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl or lower alkyl-amine; and R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkyl-amine or substituted heterocyclic compounds; so when R2 = R3 = H, then R7 and R8 are hydrogen or none. In compounds of formula III, R' is preferably carboxamide or CN and R" is hydrogen or halogens; R1 = R4 = R5 = R7 = R8 = H and R2 = R3 = OH, and preferably X is oxygen. 3. Compound according to claim 1, characterized in that it has a structure according to formula IV: [image] where: A is independently selected from N or C; B, C, E and F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2⋅HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamine, lower alkyl-alkenyl, lower alkyl-vinyl, lower alkyl aryl or substituted heterocyclic compound; X is independently O, S, CH 2 or NR; where R is COCH3; R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl or lower alkyl-amine; and R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, NH2, CH2OH, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, allyl, lower alkyl, lower alkyl-amine or a substituted heterocyclic compound; so when R2 = R3 = H, then R7 and R8 are hydrogen or none; when A is carbon; B = E = N; C is N-Ph, then F is not CH; when A = N; C is CH; B = E = C-CH3, then F is not nitrogen; and when A is carbon, B = N; C = C-CONH2; E = CH; F = S, then X is not CH2. In the compounds of formula IV, R 1 is preferably H, lower alkyl or allyl; R2 is preferably H, OH, halogens, CN, N3, NH2, C(=O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2 or C(=NH) OMe; and when R1 = R4 = R5 = R7 = R8 = H, then preferably R2 = R3 = OH and X is preferably oxygen. 4. Compound according to claim 1, characterized in that it has a structure according to formula V: [image] where: A is independently selected from N or C; B, C, E, F are independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2 or P; R 1 is independently H, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R2 is independently H, OH, halogens, CN, N3, NH2, C(-O)NH2, C(=S)NH2, C(=NH)NH2.HCl, C(=NOH)NH2, C(=NH) OMe, lower alkyl, lower alkylamine, lower alkyl-alkenyl, lower alkyl-vinyl, lower alkyl-aryl or substituted heterocyclic compound; D is independently selected from CH, CO, N, S, Se, O, NR1, CCONH2, CCH3, C-R2, P or none; R 1 is independently H, O, lower alkyl, lower alkylamine, COCH 3 , lower alkyl-alkenyl, lower alkyl-vinyl or lower alkyl-aryl. R 2 is independently H, OH, halogens, CN, N 3 , NH 2 , lower alkyl, lower alkylamine, lower alkyl alkenyl, lower alkyl-vinyl, lower alkyl-aryl or a substituted heterocyclic compound; X is independently O, S, CH 2 or NR where R is COCH 3 ; R 1 and R 4 are independently selected from H, CN, N 3 , CH 2 OH, lower alkyl and lower alkyl-amine; and R2, R3, R5, R6, R7 and R8 are independently selected from H, OH, CN, N3, halogen, CH2OH, NH2, OCH3, NHCH3, ONHCH3, SCH3, SPh, alkenyl, lower alkyl, lower alkylamine and substituted heterocyclic compound; so when R2 = R3 = H, then R7 and R8 are hydrogen or none. when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is a CH or C-substituent; F = CH; X = O, S or CH2, then R2 will not be H, OH, CH3, halogens, N3, CN, SH, SPh, CH2OH, CH2OCH3, CH2SH, CH2F, CH2N3, aryl, aryloxy or heterocyclic. when A = N; B = CO; C = N or NH; D = CO or C-NH2; E is CH, C-CH3 or halogen; F = CH; X = N-COCH3, then R2 will not be H or OH; when A = N; B = CH; C = CH or CH3; D = CH or C-CH3; E is CH, C-CH3 or C-CONH2; F = CH; X = O or CH2, then R2 will not be H or OH; when A = N; B = N, CO or CH; C = CH, C-Cl or C-OCH3; D = CH or C-Ph; E is CH, C-Cl or C-Ph; F = N or CO; X = O, then R 2 will not be H or OH; when A = N; B = CO or CS; C = N or NH; D = CO or C-NH2; E is CH or N; F = N or CH; X = O, then R 2 will not be H or OH; and when A = C; B = CH; C = NH; D = CO, CS or C-NH2; E is N or NH; F = CO or CH; X = O, then R 2 will not be H or OH. 5. A compound according to claim 1, characterized in that A, B and E are nitrogen; C is C-C(O)NH 2 ; D is nothing; F is CH; X is oxygen; R 1 , R 4 , R 5 , R 7 and R 8 are hydrogen; while R 2 , R 3 and R 6 are hydroxyl. 6. A compound according to any one of claims 1-5, characterized in that the compound contains a nucleoside. 7. A compound according to any one of claims 1-5, characterized in that the compound contains a β-nucleoside. 8. Pharmaceutical preparation, characterized in that it contains a compound according to claims 1-5, or its pharmaceutically acceptable ester or salt, which is mixed with at least one pharmaceutically acceptable carrier. 9. A method of treating a patient who is in such a state of health that it shows a positive response to the application of the compound according to any of claims 1-5, indicated by the fact that it includes: - getting a connection; - administration of the dose of the compound to the patient; and - patient monitoring regarding effectiveness or side effects. 10. The method according to claim 9, characterized in that the said condition implies an infection. 11. The method according to claim 9, characterized in that said condition implies infestation. 12. The method according to claim 9, characterized in that the said condition implies a neoplasm. 13. The method according to claim 9, characterized in that the said condition implies an autoimmune disease. 14. The method according to claim 9, characterized in that the steps of administering the compound to the patient include administering a therapeutic amount of the compound. 15. A method of modulating Th1 and Th2 activity in patients, characterized in that it includes the application of a compound according to one of claims 1-5; and administering a dose of that compound to the patient.