title: Synthesis and properties of bile acid phosphoramidites 5'-tethered to antisense oligodeoxynucleotides against HCV.
abstract: Recently, we synthesized antisense oligonucleotides (AS-ODNs) directed against the non-coding-region (NCR) and the adjacent core region of the hepatitis C virus (HCV) RNA. Backbone modifications like phosphorothioates, methyl- and benzylphosphonates were introduced three at each end of the sequence. For improvement of liver specific drug targeting and/or hepatocellular uptake efficient AS-ODNs were covalently conjugated to biomolecules such as cholesterol or bile acids. The use of base-labile alkylphosphonates afforded mild conditions for deprotection of bile acid conjugated AS-ODNs. Here, we describe a convenient synthesis of new cholic acid and taurocholic acid phosphoramidites. Derivatization to taurocholic acid was effected directly before phosphitylation reaction, which is the last step of the phosphoramidite synthesis. These building blocks were coupled to the 5'-position of AS-ODNs in the last step of solid-phase synthesis. After mild deprotection, purification and characterization the properties of these modified AS-ODNs like their lipophilicity or their ability to form stable duplices to DNA and RNA were investigated. Enhanced lipophilicity and formation of stable duplices and heteroduplices makes bile acid conjugated AS-ODNs interesting as antiviral antisense therapeutics against HCV.
authors: Institute of Organic Chemistry, Johann Wolfgang Goethe-University, Marie-Curie-Strasse 11, D-60439 Frankfurt am Main, Germany.
authors: T J
authors: TJ
authors: Lehmann
authors: J W
authors: JW
authors: Engels
mesh_terms: D001647:Bile Acids and Salts / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D016174:Hepacivirus / Q000235:genetics*; D009682:Magnetic Resonance Spectroscopy; D016376:Oligonucleotides, Antisense / Q000737:chemistry* / Q000235:genetics; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001647:Bile Acids and Salts; D016376:Oligonucleotides, Antisense; D009943:Organophosphorus Compounds