title: Ethynyl side chain hydration during synthesis and workup of "clickable" oligonucleotides: bypassing acetyl group formation by triisopropylsilyl protection.
abstract: Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines ((eth)dC and (eth)dU) or the 7-position of 7-deazaguanine ((eth)c(7)G(d)) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → acetyl group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, acetyl group free oligonucleotides were isolated after desilylation in all cases.
authors.affiliation: Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology , Heisenbergstraße 11, 48149 Münster, Germany.
authors.forename: Sachin A
authors.initials: SA
authors.lastname: Ingale
authors.forename: Hui
authors.initials: H
authors.lastname: Mei
authors.forename: Peter
authors.initials: P
authors.lastname: Leonard
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
mesh_terms: D003432:Cross-Linking Reagents / Q000138:chemical synthesis* / Q000737:chemistry; D006147:Guanine / Q000031:analogs & derivatives / Q000737:chemistry; D006868:Hydrolysis; D008968:Molecular Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D009841:Oligonucleotides; D011743:Pyrimidines; D012821:Silanes; D014867:Water; D006147:Guanine