Synthesis of purine modified 2'-C-methyl nucleosides as potential anti-HCV agents

Based on the anti-hepatitis C activity of 2′-C-methyl-adenosine and 2′-C-methyl-guanosine, a series of new modified purine 2′-C-methyl nucleosides was prepared as potential anti-hepatitis C virus agents. Herein, we report the synthesis of both 6-modified and 2-modified purine 2′-C-methyl-nucleosides along with their anti-HCV replication activity and cytotoxicity in different cells.     

Synthesis and biological activity of 4'-C-hydroxymethyl-2'-fluro-D-arabinofuranosylpurine nucleosides

A series of 4'-C-hydroxymethyl-2'-fluoro-D-arabinofuranosylpurine nucleosides was prepared and evaluated for cytotoxicity. The details of a convenient synthesis of the carbohydrate precursor 4-C-hydroxymethyl-3,5-di-O-benzoyl-2-fluoro-alpha-D-arabinofuranosyl bromide (13) are presented. Proof of the structure and configuration at all chiral centers of the sugars and the nucleosides were obtained by proton NMR. All five target nucleosides were evaluated for cytotoxicity in human tumor cell lines. The 4'-C-hydroxymethyl clofarabine analogue (16beta) showed slight cytotoxicity in CCRF-CEM leukemia cells.     

Synthesis and anti-HCV activity evaluation of anilinoquinoline derivatives

Hepatitis C virus (HCV) infection is a main cause of chronic liver disease, leading to liver cirrhosis and hepatocellular carcinoma (HCC). The objective of our research was to develop effective agents against viral replication. Here, we have synthesized a series of anilinoquinoline derivatives. Based on a cell-based HCV replicon system, we observed that 2-(3'-nitroanilino)quinoline (18) exhibited anti-HCV activity with a 50% effective concentration (EC(50)) value of 7μM and a selective index (SI) value of 10. In addition, compound 18 possessed the inhibitory effect on HCV NS3/4A protease activity. Therefore, we concluded that the compound 18 possessed a potent activity against HCV replication and could provide as a new lead compound as anti-HCV inhibitor.     

Synthesis and biological activity of 4'-C-hydroxymethyl-2'-fluoro-D-arabinofuranosylpurine nucleosides

A series of 4'-C-hydroxymethyl-2'-fluoro-D-arabinofuranosylpurine nucleosides was prepared and evaluated for cytotoxicity in human tumor cell lines. A convenient synthesis of the carbohydrate precursor 4-C-hydroxymethyl-3,5-di-O-benzoyl-2-fluoro-alpha-D-arabinofuranosyl bromide (13) was developed. Coupling of 13 with the sodium salt of 2,6-dichloropurine led to five target purine nucleosides.     

Synthesis and anti-HCV activity of a new 2'-deoxy-2'-fluoro-2'-C-methyl nucleoside analogue

2'-Deoxy-2'-fluoro-2'-C-methyl nucleoside analogue 4 was designed and synthesized. Initial biological studies indicated that this compound showed promising activity against HCV replication.     

Synthesis and in vitro anti-HCV activity of beta-D- and 1-2'-deoxy-2'-fluororibonucleosides

Based on the discovery of beta-D-2'-deoxy-2'-fluorocytidine as a potent anti-hepatitis C virus (HCV) agent, a series of beta-D- and L-2'-deoxy-2'-fluoroibonucleosides with modifications at 5 and/or 4 positions were synthesized and evaluated for their in vitro activity against HCV and bovine viral diarrhea virus (BVDV). The introduction of the 2'-fluoro group was achieved by either fluorination of 2,2'-anhydronucleosides with hydrogen fluoride-pyridine or potassium fluoride, or a fluorination of arabinonucleosides with DAST. Among the 27 analogues synthesized, only the 5-fluoro compounds, namely beta-D-2'-deoxy-2',5-difluorocytidine (5), had anti-HCV activity in the subgenomic HCV replicon cell line, and inhibitory activity against ribosomal RNA. As beta-D-N4-hydroxycytidine (NHC) had previously shown potent anti-HCV activity, the two functionalities of the N4-hydroxyl and the 2'-fluoro were combined into one molecule, yielding beta-D-2'-deoxy-2'-fluoro-N4-hydroxycytidine (12). However, this nucleoside showed neither anti-HCV activity nor toxicity. All the L-forms of the analogues were devoid of anti-HCV activity. None of the compounds showed anti-BVDV activity, suggesting that the BVDV system cannot reliably predict anti-HCV activity in vitro.     

Synthesis and biological activity of 2-aminopurine methylenecyclopropane analogues of nucleosides

Synthesis and biological activity of 7- and 9-isomers (Z+E) of methylenecyclopropane analogues of 2-aminopurine nucleosides is described. The (S,Z)-9-isomer is a substrate for xanthine oxidase.     

Synthesis and biological activity of 4'-thio-2'-deoxy purine nucleosides.

Coupling of 1-O-acetyl-2-deoxy-3,5-di-O-toluoyl-4-thio-D-ribofuranose with 6-chloropurine and 2,6-dichloropurine gave a mixture of 9 alpha and 9 beta anomers as major products. These anomers were separated and converted to 2'-deoxy-4'-thio analogues of adenosine, inosine, guanosine, 2-amino-adenosine, and 2-chloro adenosine as well as their alpha-anomers.     

Synthesis and biological activity of 4'-thio-L-xylofuranosyl nucleosides

A series of 4'-thio-L-xylofuranosyl nucleosides were prepared and evaluated as potential anticancer and antiviral agents. The details of a convenient and high-yielding synthesis of the carbohydrate precursor 1-O-acetyl-2,3,5-tri-O-benzyl-4-thio-L-xylofuranose (6) are presented. Proof of structure and configuration at all chiral centers of the nucleosides was obtained by proton and carbon NMR. All target compounds were evaluated in a series of human cancer cell lines in culture and as antiviral agents.     

Synthesis and anti-virus activity of some nucleosides analogues

New 3'-, 5'-, 5-bromo-2'-deoxyuridine (3a-g) and 3'-, 5'-thymidine (4a-i) analogues with amino acid and peptide residues were synthesized and evaluated for antiviral activity. The influence of long peptide chains, essential amino acids and the effect of this structural modification on the antiviral activity has been also reported. Three 5-bromo-2'-deoxyuridine derivatives containing glycyl-, glycyl-glycyl- and glycyl-glycyl-glycyl- residues (3a, 3b, 3c) showed a strong activity against the herpes virus PsRV and a moderate one vs. HSV-1. The corresponding thymidine analogues were considerably less effective, and only compounds 4d and 4h showed a borderline effect against PsRV.     

Synthesis and biological activity of modified thiopyrimidine nucleosides

N3-beta-D-glucopyranosyl, galactopyranosyl and xylopyranosyl 6-methyl-2-methylthiouracil and their 5-bromo derivatives have been synthesized by coupling an alpha-acetobromosugar with the corresponding thiouracil. The new modified thiouridine analogues were evaluated for their inhibitory activity against Human Immunodeficiency Virus (HIV) replication in MT-4 cells as well as for their cytotoxicity.     

Synthesis and biological activity of chloroethyl pyrimidine nucleosides

The synthesis and biological activity of chloroethyl pyrimidine nucleosides is presented. One of these new nucleosides analogues significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.     

Synthesis and biological activity of novel carbocyclic nucleosides

The syntheses of several novel carbocyclic nucleosides which incorporate the cyclopentene moiety of neplanocin A will be presented. These include modified pyrimidine derivatives of the very potent antitumor agent cyclopentenyl cytosine and carbocyclic analogues of the ketohexose nucleosides psicofuranine and psicofuranosyl cytosine.     

Synthesis and antiviral activity of methylenedifluorocyclopropane analogues of nucleosides

Synthesis and antiviral activity of methylenedifluorocyclopropane analogues 8a, 8b and 9a, 9b are described.     

Synthesis and anti-HIV activity of different novel nonclassical nucleosides

A series of different novel nonclassical nucleosides have been synthesised and evaluated for their inhibitory activity against human immunodeficiency virus (HIV) replication in MT-4 cells.     

New acyclic quinoxaline nucleosides. Synthesis and anti-hiv activity

A series of acyclonucleosides substituted 1-(4,5-dihydroxypentyl) (13-8) and 2-(4,5-dihydroxypentyloxy)quinoxalines (19-24) were synthesized by the sharpless asymmetric dihydroxylation of the derivatives 1-6 and 7-12, respectively. Treatment of the quinoxaline base 26 with (R)-2,2-dimethyl-1,3-dioxolan-4-ylmethyl-p-toluenesulfonate (27) in the presence of NaH/DMF furnished 28. Acid hydrolysis of 28 gave 1-(2,3-dihydroxypropyl)-6,7-dimethyl-quinoxaline-2-one (29). Alternatively, 29 was prepared by sharpless dihydroxylation of 30. All the compounds were evaluated for their in vitro anti-HIV-1 and HIV-2 in MT-4 cell and found inactive, except 29, which showed inhibition of HIV-1 with EC50 value of 0.15 +/- 0.1 microg/ml and a therapeutic index (SI) of 73.     

Synthesis and antiherpesviral activity of 5-C-substituted uracil nucleosides

Reaction of 2'-deoxy-5-hydroxyuridine with some Wittig reagents gave 5-alkoxycarbonylmethyl-, 5-carbamoylmethyl-, 5-cyanomethyl-and 5-acetonyl-2'-deoxyuridines. The corresponding 1-beta-D-arabinofuranosyl derivatives were prepared from 1-beta-D-arabinofuranosyl-5-hydroxymethyluracil. The latter was also converted to 1-beta-D-arabinofuranosyl-5-vinyluracil via triphenylphosphonium salt, and then to 5-(2-halogenovinyl)derivatives. Some of these compounds showed marked antiherpesviral activity in vitro.     

Synthesis and DNA topoisomerase-II inhibitory activity of unnatural nucleosides

The synthesis and biological activities of a number of unnatural nucleosides (23-43) is described. Nucleosides have been synthesized by SnCl4-catalyzed condensation of amino sugar acetates and silylated modified pyrimidines. Few of the 2'-O-acetyl derivatives of the nucleosides were hydrolyzed to the respective hydroxy derivatives by treatment with methanol saturated with ammonia. The compounds were screened against Filarial DNA-topoisomerase-II but only one of the compounds (29) inhibited this enzyme at 40 microg/mL of reaction mixture.     

Synthesis of 2'-amino-LNA purine nucleosides

The first reported synthesis of 2'-amino-LNA purine nucleosides via a transnucleosidation is accomplished enabling the preparation of oligonucleotides incorporating 2'-amino-LNA with all four natural bases.