Reaction SMILES: [C:1]([SiH2:5][O:6][C:7]([C:34]1[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=1)([C:28]1[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=1)[CH:8]1[O:12][CH:11]([N:13]2[CH:18]=[CH:17][C:16]([N:19]=[CH:20][N:21]([CH3:23])[CH3:22])=[N:15][C:14]2=[O:24])[C:10]([OH:26])([CH3:25])[CH:9]1[OH:27])([CH3:4])([CH3:3])[CH3:2].[C:40]([NH:47][C@H:48]([C:52](O)=[O:53])[CH:49]([CH3:51])[CH3:50])([O:42][C:43]([CH3:46])([CH3:45])[CH3:44])=[O:41]>CN(C1C=CN=CC=1)C.C1COCC1.CN(C=O)C>[C:1]([SiH2:5][O:6][C:7]([C:28]1[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=1)([C:34]1[CH:35]=[CH:36][CH:37]=[CH:38][CH:39]=1)[CH:8]1[CH:9]([O:27][C:52](=[O:53])[CH:48]([NH:47][C:40]([O:42][C:43]([CH3:44])([CH3:46])[CH3:45])=[O:41])[CH:49]([CH3:51])[CH3:50])[C:10]([OH:26])([CH3:25])[CH:11]([N:13]2[CH:18]=[CH:17][C:16]([N:19]=[CH:20][N:21]([CH3:22])[CH3:23])=[N:15][C:14]2=[O:24])[O:12]1)([CH3:2])([CH3:3])[CH3:4]
Reactant: CN(C)C=Nc1ccn(C2OC(C(O[SiH2]C(C)(C)C)(c3ccccc3)c3ccccc3)C(O)C2(C)O)c(=O)n1
Reactant: CC(C)[C@H](NC(=O)OC(C)(C)C)C(=O)O
Agent: CN(C)c1ccncc1
Solvent: C1CCOC1
Solvent: CN(C)C=O
Product: CC(C)C(NC(=O)OC(C)(C)C)C(=O)OC1C(C(O[SiH2]C(C)(C)C)(c2ccccc2)c2ccccc2)OC(n2ccc(N=CN(C)C)nc2=O)C1(C)O

Procedure:
In another method to synthesize the compounds of the invention, shown in FIG. 6, benzoylcytosine, BSA and SnCl4/acetonitrile are reacted with 1,2,3,5-tetra-O-benzoyl-2-C-methyl-β-D-ribofuranose (FIG. 6, compound 1a) to form 4-benzoylamino-1-(3,4-dibenzoyloxy-5-benzoyloxymethyl-3-methyl-tetrahydro-furan-2-yl)-1H-pyrimidin-2-one (FIG. 6, compound 2a); reacting (FIG. 6, compound 2a) with NH3 in methanol and chromatographically separating the product, 4-amino-1-(3,4-dihydroxy-5-hydroxymethyl-3-methyl-tetrahydro-furan-2-yl)-1H-pyrimidin-2-one (FIG. 6, compound 3a), also known as β-D-2′-C-methyl-cytidine; reacting (FIG. 6, compound 3a) with Me2NCH(OMe)2 in DMF at room temperature for 1.5 hours to form N-[1-(3,4-dihydroxy-5-hydroxymethyl-3-methyl-tetrahydro-furan-2-yl)-2-oxo-1,2-dihydro-pyrimidin-4-yl]-N,N-dimethyl-formamidine (FIG. 6, compound 4a); reacting (FIG. 6, compound 4a) with TBDPSCl and pyridine at room temperature for 6 hours to provide N′-{1-[5-(tert-butyl-diphenyl-silanyloxymethyl)-3,4-dihydroxy-3-methyl-tetrahydro-furan-2-yl]-2-oxo-1,2-dihydro-pyrimidin-4-yl}-N,N-dimethyl-formamidine (FIG. 6, compound 5a); reacting (FIG. 6, compound 5a) with N-Boc-L-valine, DEC and DMAP in THF/DMF at room temperature for 2 days and subjecting the product formed from this reaction to HPLC in order to provide 2-tert-butoxycarbonylamino-3-methyl-butyric acid 2-(tert-butyl-diphenyl-silanyloxy-methyl)-5-[4-(dimethylaminomethyleneamino)-2-oxo-2H-pyrimidin-1-yl]-4-hydroxy-4-methyl-tetrahydro-furan-3-yl ester (FIG. 6, compound 6a); refluxing (FIG. 6, compound 6a) with NH4F in MeOH for about 3 hours to remove the silyl and amino-protecting groups, and subjecting the product to chromatographic purification to provide 2-tert-butoxycarbonylamino-3-methyl-butyric acid 5-(4-amino-2-oxo-2H-pyrimidin-1-yl)-4-hydroxy-2-hydroxymethyl-4-methyl-tetrahydro-furan-3-yl ester (FIG. 6, compound 7a); and finally reacting (FIG. 6, compound 7a) with HCl in EtOAc at room temperature to provide 2-amino-3-methyl-butyric acid 5-(4-amino-2-oxo-2H-pyrimidin-1-yl)-4-hydroxy-2-hydroxymethyl-4-methyl-tetrahydro-furan-3-yl ester, dihydrochloride salt (FIG. 6, compound 8a) as a final product.