Halo-nucleosides

4-Deoxy-4-fluoro-D-glucopyranosyl thymine and 2-deoxy-2-fluoro-D-arabino-furanosyl derivatives of 5-substituted-cytosine and -uracil have been prepared by standard methods from the corresponding fluoro-sugar the uracil derivatives stopped replication of Herpes simplex virus (HSV-1) in vitro. 5-Deoxy-5-iodo-adenosine derivatives have also been prepared from iodo sugars.  

Treatment of nucleosides with thionyl chloride in HMPT gave 5 -chloro-5-deoxy-2, 3 Sulphinyl derivatives, which could be converted to 5 -chloro-5-deoxy-nucleosides on treatment with sodium methoxide in methanol, or to 2,2 -anhydro-nucleosides with imidazole in Likewise 2-deoxy- 

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Similarly, heptamethyltrisilane (K), heptamethyltrisilanethiol (L), 5,10-dihydro-disilanthracene (M) also reduce organic halides and xanthates, though the reactivities are decreased and they cannot be used for C-C bond formation [18, 19]. Reagent (N) is water-soluble monosilane and it can reduce sugar halides and halo-nucleosides in water [20]. However, the reactivity is low and it can only be used for the reduction of organic... 

Mixed anhydrides of carboxylic acids (RCO2H) and thiohydroxamic acid react with Sb(SPh)3 in the presence of O2 and water to give alcohols (ROH) via RSb(SPh)2 intermediates (Scheme 14.7) [28]. Both thioethers and sulfoxides bearing a hydrogen atoms are converted to a-fluorothioethers by treatment wifh (diefhylamino)sulfur trifluoride under Sb(.T, catalysis (Scheme 14.8) [29]. Treatment of 2-amino-6-halo nucleosides with tert-butyl nitrite in the presence of SbCls affords the 2-chloro-6-halopurine nucleosides (Scheme 14.9) [30]. 

Deoxy-2-halogeno-arabinosyl bromides have been used to prepare halo-nucleosides from 5-substituted-uracil or -cytosine bases leading to 2 -bromo, 2 -chloro, and 2 -fluoro-arabino-nucleoside analogues the 2 -fluoro analogues were most effective as anti-viral 48... 

Treatment of 5 -bromo- or 5 -chloro-5 -deoxy-ara cytosine with basic ion-exchange resin yields the 2, 5 -anhydro nucleoside biochemical studies suggest that the anhydro nucleoside is the effective cause of the biological activity of the halo-nucleoside precursors. ... 

Purine, 2,6-dithioxo-1,2,3,6-tetrahydro-dethiation, 5, 558 Purine, 8-ethoxy-synthesis, 5, 577, 596 Purine, 6-ethoxycarbonylmethyl-nucleoside synthesis, 5, 561 Purine, 8-ethoxy-7-methyl-synthesis, 5, 577 Purine, 9-ethyl-synthesis, 5, 593 Purine, 6-fonnyl-reactions, 5, 547 synthesis, 5, 593 Purine, 8-fonnyl-reactions, 5, 547 Purine, 2-fluoro-synthesis, 5, 597 Purine, 6-fluoro-alkylation, 5, 529 synthesis, 5, 563, 573 Purine, 6-fluoro-9-methyl-reactions, with ammonia, 5, 562 Purine, 6-furfurylamino- — see Kinetin Purine, 9-glycofuranosyl-synthesis, 5, 572 Purine, 2-glycosyl-synthesis, 5, 587 Purine, 8-glycosyl-synthesis, 5, 585 Purine, 9-glycosyl-synthesis, 5, 572 Purine, 8-halo-synthesis, 5, 598 Purine, 2-hydrazino-synthesis, 5, 593 Purine, 8-o -hydroxyethyl-synthesis, 5, 574... 

Purines, N-alkyl-N-phenyl-synthesis, 5, 576 Purines, alkylthio-hydrolysis, 5, 560 Mannich reaction, 5, 536 Michael addition reactions, 5, 536 Purines, S-alkylthio-hydrolysis, 5, 560 Purines, amino-alkylation, 5, 530, 551 IR spectra, 5, 518 reactions, 5, 551-553 with diazonium ions, 5, 538 reduction, 5, 541 UV spectra, 5, 517 Purines, N-amino-synthesis, 5, 595 Purines, aminohydroxy-hydrogenation, 5, 555 reactions, 5, 555 Purines, aminooxo-reactions, 5, 557 thiation, 5, 557 Purines, bromo-synthesis, 5, 557 Purines, chloro-synthesis, 5, 573 Purines, cyano-reactions, 5, 550 Purines, dialkoxy-rearrangement, 5, 558 Purines, diazoreactions, 5, 96 Purines, dioxo-alkylation, 5, 532 Purines, N-glycosyl-, 5, 536 Purines, halo-N-alkylation, 5, 529 hydrogenolysis, 5, 562 reactions, 5, 561-562, 564 with alkoxides, 5, 563 synthesis, 5, 556 Purines, hydrazino-reactions, 5, 553 Purines, hydroxyamino-reactions, 5, 556 Purines, 8-lithiotrimethylsilyl-nucleosides alkylation, 5, 537 Purines, N-methyl-magnetic circular dichroism, 5, 523 Purines, methylthio-bromination, 5, 559 Purines, nitro-reactions, 5, 550, 551 Purines, oxo-alkylation, 5, 532 amination, 5, 557 dipole moments, 5, 522 H NMR, 5, 512 pJfa, 5, 524 reactions, 5, 556-557 with diazonium ions, 5, 538 reduction, 5, 541 thiation, 5, 557 Purines, oxohydro-IR spectra, 5, 518 Purines, selenoxo-synthesis, 5, 597 Purines, thio-acylation, 5, 559 alkylation, 5, 559 Purines, thioxo-acetylation, 5, 559... 

Removal of the 2 -sulfonyloxy group of 859 in a basic medium, followed by reaction with metal halides (LiBr and Nal) or hydrogen halides (HCl-1,4-dioxane, HBr-acetone, or0.1% HFin l,4-dioxane-AlF3)gave, byway of the 2,2 -anhydro intermediate 861, the 2 -halo derivatives 862-865. The 2 -deoxy analog 866 and l-(6-deoxy-6-fluoro- ff-D-mannopyranosyl)thy-mine were also prepared from 864 (R = H) and 861 (R = H), respectively. l-(4-Deoxy-4-fluoro-y -D-glucopyranosyl)thymine was obtained by the condensation method. A different kind of nucleoside, 5-(5-deoxy-5-fluoro-2,3-0-isopropylidene-a-D-ribofuranosyl)-l,3-dimethyluracil has also been prepared. ... 

Verheyden, J.P.H. and Moffatt, J.G., Halo sugar nucleosides. I. Iodination of the primary hydroxyl groups of nucleosides with methyltriphenoxyphospho-nium iodide, /. Org. Chem., 35, 2319, 1970. 

J. P. Verheyden and J. G. Moffatt, Halo sugar nucleosides. III. Reactions for the chlorination and bromination of nucleoside hydroxy groups, J. Org. Chem. 37 2289 (1972). 

After it was demonstrated that silylated sugars easily form diglycosides225 when they are applied to 1-halo-sugars, further studies followed. It became apparent that these silylated heterocycles are convenient intermediates, especially for the synthesis of nucleosides when acylated 1-halo-sugar are employed224,22S. ... 

The interest in the sugar derivatives of some of these systems as isosteres of purine nucleosides has led to considerable research into their direct electrophilic coupling reactions with halo-sugars or other activated sugars. Generally however, electrophilic attack occurs at several positions as is evident with 7-amino-1,2,3-triazolo[4,5-t/]pyrimidine (54a), the so-called 8-azaadenine , giving rise... 

Heterocondensed uracils are easily accessible from acyllactones, -lactams, -thiollactones (72S151), and heterocyclic /3-enamino esters, especially (85AHC299). The latter gives a broad range of novel types of condensed systems. With the aid of the hexamethyldisilazane trimethyl-chlorosilane (HMDS/TMSC1) technique or the use of NaH and halo-sugars, respectively, simple approaches have been developed to obtain unusual nucleosides [92JPR(ip)] (Scheme 15). 

Ishii, A., Otsuka, T., Kume, K., et al. (2006) Regioselective preparation of 2-halo-2,3-dideoxy-3-fluoro-P-D-arabinofuranosyl nucleosides and their dehalogenation products. IP Patent 2006022009. 

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