Utilization of intrachain 4'-C-azidomethylthymidine for preparation of oligodeoxyribonucleotide conjugates by click chemistry in solution and on a solid support.
4'-C-Azidomethylthymidine 3'-(H-phosphonate) monomer (10) was synthesized in high yield and three such monomers were incorporated by the H-phosphonate coupling into a 15-mer oligodeoxyribonucleotide. The unmodified 2'-deoxynucleosides could be coupled by either the H-phosphonate or phosphoramidite chemistry, indicating that the Staudinger reaction between the azido group and the phosphoramidite reagent severely hampered the coupling only when it took place intramolecularly. After chain assembly, three alkynyl group bearing ligands, viz., propargyl 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranoside (2), N-{4-[N-(trifluoroacetyl)aminomethyl]benzyl}-4-pentynamide (3) and N (1), N (3), N (2')-tris(trifluoroacetyl)-N (6')-(4-pentynoyl)neamine (4), were conjugated to the azido groups of the oligonucleotide by click chemistry both on a solid support and in solution. The products were deprotected by conventional ammonolysis and purified by HPLC chromatography. Melting temperature studies revealed that the mannose conjugated oligonucleotides formed more stable duplexes with 2'-O-methyl RNA than with DNA strand. With 2'-O-methyl RNA, a slight destabilization compared to an unmodified sequence was observed at low ionic strength, while at high salt content, the manno-conjugation was stabilizing.
Kiviniemi
Anu
A
Department of Chemistry, University of Turku, FIN-20014 Turku, Finland. ankaka@utu.fi
Virta
Pasi
P
Lönnberg
Harri
H
D001483:Base Sequence; D017665:Hydroxyl Radical / Q000737:chemistry; D008024:Ligands; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012996:Solutions; D055672:Static Electricity; D013936:Thymidine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D044366:Transition Temperature
C532333:4'-C-azidomethylthymidine; D008024:Ligands; D009838:Oligodeoxyribonucleotides; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D017665:Hydroxyl Radical; D013936:Thymidine