Enantioselective synthesis of N,O-psiconucleosides

C-5'-Triazolyl-2'-oxa-3'-aza-4'a-carbanucleosides: Synthesis and biological evaluation

A novel series of 2’-oxa-3’-aza-4’a-carbanucleosides, featured with a triazole linker at the 5’-position, has been developed by exploiting a click chemistry reaction of 5’-azido-2’-oxa-3’-aza-4’a-carbanucleosides with substituted alkynes. Biological tests indicate an antitumor activity for the synthesized compounds: most of them inhibit cell proliferation of Vero, BS-C-1, HEp-2, MDCK, and HFF cells with a CC₅₀ in the range of 5.0–40 μM. The synthesized compounds do not show any antiviral activity.

Synthesis of monoglycosides, bisglycosides and open-chain ketoacetals from sugar derived exocyclic enol ethers

Pent-4-enofuranoside derivatives have been converted to glycosides and open-chain ketoacetals on treatment with various alcohols under acidic conditions.

Synthesis and biological evaluation of furopyrimidine N,O-nucleosides

A series of modified N,O-nucleosides, characterized by the presence of a furopyrimidine moiety, has been synthesized by exploiting a Sonogashira cross coupling reaction of 1-isoxazolidinyl-5-iodouracil with alkynes, followed by treatment with CuI in refluxing TEA/MeOH mixture. The obtained compounds were screened against both RNA and DNA viruses. None of the compounds were endowed with antiviral activity at subtoxic concentrations. However, some of them were able to inhibit proliferation of MRC-5, Vero, BS-C-1 cells by 50% (CC50) at concentrations ranging from 0.7 to 62.5 mM.

Study of the Effects on DNA of Two Novel Nucleoside Derivatives Synthesized as Potential Anti-HIV Agents

The pursuit of antiviral active compounds against different classes of viruses, in particular HIV, HBV, and HTLV is an area of important and intense research. In the current study, two novel nucleoside derivatives belonging to a new class of isoxazolidine were successfully synthesized as potential anti-HIV agents by replacement of the furanose ring by a N,O-heterocyclic ring Both compounds were investigated for biological activity, namely, mutagenic and antimutagenic properties. Using Salmonella typhimurium strains TA97, TA100, and TA102, both compounds proved to be nonmutagenic, which may be considered an encouraging result to further elucidate other biological activities. Antimutagenic testing of the synthesized compounds revealed that they are active against the base-pair substitution mutagen sodium azide. However, they did not show any indication as antimutagenic agents against hydrogen peroxide and mitomycin C (oxidative mutagens) or against nitrophenylenediamine (a base-pair substitution and frameshift mutagen). Structure-activity relationship is also discussed. Testing these compounds as antiviral agents is highly recommended.

Synthesis and biological evaluation of phosphonated dihydroisoxazole nucleosides

Phosphonated isoxazolinyl nucleosides have been prepared via 1,3-dipolar cycloaddition reaction of nitrile oxides with corresponding vinyl or allyl nucleobases for antiviral studies. The cytotoxicity, the anti-HSV activity and the RT-inhibitory activity of the obtained compounds were evaluated and compared with those of AZT and diethyl{(1'SR,4'RS)-1'-[[(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)]-3'-methyl-2'-oxa-3'-azacyclopent-4'-yl]}methylphosphonate, a saturated phosphonated dihydroisoxazole nucleoside analogue.

Zinc(II) Triflate-Controlled 1,3-Dipolar Cycloadditions of C-(2-Thiazolyl)nitrones: Application to the Synthesis of a Novel Isoxazolidinyl Analogue of Tiazofurin

[reaction: see text] The cycloaddition reaction between C-(2-thiazolyl) nitrones and allylic alcohol takes place with complete exo selectivity when the reactions are carried out in the presence of 1 equiv of zinc triflate. The rate of the reaction is increased enormously under microwave irradiation. The use of a chiral dipolarophile allowed application of the methodology to the synthesis of a hitherto unknown enantiomerically pure isoxazolidinyl analogue of the C-nucleoside tiazofurin.

4′-α-C-Branched N,O-nucleosides: synthesis and biological properties

The synthesis of 4'-alpha-C-branched N,O-nucleosides has been described, based on the 1,3-dipolar cycloaddition of nitrones with vinyl acetate followed by coupling with silylated nucleobases, The obtained compounds have been evaluated for their activity against HSV-1, HSV-2, HTLV-1. Cytotoxicity and apoptotic activity have been also investigated: compound 10c shows moderate apoptotic activity in Molt-3 cells.