BACKGROUND Several published studies indicate that the acyclic guanine nucleoside analogues possessing bis(1,2-hydroxymethyl) substituted cyclopropane rings mimicking the sugar moiety are potent inhibitors of replication of several herpes viruses. METHODS Established synthetic methods and antiviral and cytostatic activity assays were used for the evaluation of new 1,2,4-triazole and purine ac...

To prepare the target nucleosides, the branched chain sugars was converted to their active form (1-bromosugar derivatives). This conversion included the hydrolysis of bromination with hydrobromic acid (HBr) in glacial acetic acid, forming 1-bromo sugars (4,6-di-O-Acetyl-2,3-dideoxy-3,3-di-C-nitro methyl-Darabinohexopyranosyl bromide), which were subjected to condensation with theophylline mercu...

Several novel nucleoside analogues as potential inhibitors of glycosidases and purine nucleoside phosphorylase (PNP) have been synthesized via selective coupling of an appropriate nucleobase at different positions of an orthogonally protected imino sugar as a common precursor. This synthetic strategy offers a straightforward protocol for the assembly of imino sugar containing nucleosides, estab...

Constitutive and inducible nucleoside-binding sites on the surface of the cells of E. coli B have different patterns of inhibition by nucleoside analogues. 1(beta-D-Ribofuranosyl)-4-aminopyrimidine-6-one and isoguanosine preferentially inhibit the inducible binding sites while showdomycin and N(4)-dimethylcytidine interfere more strongly with the constitutive function.

Spironucleosides are a type of conformationally restricted nucleoside analogs in which the anomeric carbon belongs simultaneously to the sugar moiety and to the base unit. This locks the nucleic base in a specific orientation around the N-glycosidic bond, imposing restrictions on the flexibility of the sugar moiety. Anomeric spiro-functionalized nucleosides have gained considerable importance w...

Nucleoside analogues are broadly used in antiviral and anti-tumor therapy. The clinical response depends on the intracellular formation of the pharmacologically active mono-, di-, and tri-phosphates moiety. So it is not advisable to simply monitor plasma concentration without concerning the variation of concentration of active constituent in some particular effector cell apparently while this k...

We have studied the potential contribution of ABCG2 (breast cancer resistance protein) to resistance to nucleoside analogues. In cells transfected with DNA constructs resulting in overexpression of human or mouse ABCG2, we found resistance against cladribine, clofarabine, fludarabine, 6-mercaptopurine, and 6-mercaptopurine riboside in both MDCKII and HEK293 cells and against gemcitabine only in...

Protected N-branched nucleoside phosphonates containing adenine and thymine bases were prepared as the monomers for the introduction of aza-acyclic nucleotide units into modified oligonucleotides. The phosphotriester and phosphoramidite methods were used for the incorporation of modified and natural units, respectively. The solid phase synthesis of a series of nonamers containing one central mo...