title: Solid-supported 2'-O-glycoconjugation of oligonucleotides by azidation and click reactions.
abstract: 2'-O-[(2-Bromoethoxy)methyl]cytidine and 2'-O-[(2-azidoethoxy)methyl]cytidine have been prepared and introduced as appropriately protected 3'-phosphoramidite (1) and 3'-(H-phosphonate) (2) building blocks, respectively, into 2'-O-methyl oligoribonucleotides. The support-bound oligonucleotides were subjected to two consecutive conjugations with alkynyl-functionalized monosaccharides. The first saccharide was introduced by a Cu(I) promoted click reaction with 2 and the second by azidation of the 2-bromoethoxy group of 1 followed by the click reaction. The influence of the 2'-glycoconjugations on hybridization with DNA and 2'-O-methyl RNA targets was studied. Two saccharide units within a 15-mer oligonucleotide had a barely noticeable effect on the duplex stability, while introduction of a third one moderately decreased the melting temperature.
authors.affiliation: Department of Chemistry, University of Turku, FIN-20014 Turku, Finland. anu.kiviniemi@utu.fi
authors.forename: Anu
authors.initials: A
authors.lastname: Kiviniemi
authors.forename: Pasi
authors.initials: P
authors.lastname: Virta
authors.forename: Mikhail S
authors.initials: MS
authors.lastname: Drenichev
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Mikhailov
authors.forename: Harri
authors.initials: H
authors.lastname: Lönnberg
mesh_terms: D001386:Azides / Q000737:chemistry*; D002236:Carbohydrate Conformation; D057930:Click Chemistry; D004247:DNA / Q000737:chemistry; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000737:chemistry; D012313:RNA / Q000737:chemistry
chemical_list: D001386:Azides; D009841:Oligonucleotides; D012313:RNA; D004247:DNA