title: Microwave-assisted phosphitylation of DNA and RNA nucleosides and their analogs.
abstract: Microwave-assisted chemical phosphitylation of novel nucleoside analogs containing a ribulose sugar unit was successful with yields ranging from 50% to 79% using 2-cyanoethyl-N,N-diisopropyl chlorophosphoramidite as the phosphitylating reagent. The resultant phosphoramidite products remained intact, with no signs of degradation over extended reaction times (up to 60 min) at an elevated temperature (65°C). When the same microwave-mediated phosphitylating protocols were applied to canonical DNA and RNA nucleoside monomers as substrates, using either 2-cyanoethyl-N,N,-diisopropyl chlorophosphoramidite or 2-cyanoethyl-N,N,N',N'-tetraisopropyl phosphane with an activator, 40% to 90% yields of DNA and RNA phosphoramidites were obtained within 10 to 15 min. These results demonstrate that microwave-assisted phosphitylation is an efficient alternative to standard phosphitylating conditions that can be expanded and refined to include a variety of substrates.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, La Jolla, California.
authors.forename: Tim
authors.initials: T
authors.lastname: Efthymiou
authors.affiliation: Department of Chemistry, The Scripps Research Institute, La Jolla, California.
authors.forename: Ramanarayanan
authors.initials: R
authors.lastname: Krishnamurthy
mesh_terms: D004247:DNA / Q000737:chemistry*; D008872:Microwaves; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012313:RNA / Q000737:chemistry*
chemical_list: D009705:Nucleosides; D009943:Organophosphorus Compounds; C434331:phosphoramidite; C049084:2-cyanoethyl-N,N,N',N'-tetraisopropylphosphorodiamidite; D012313:RNA; D004247:DNA
keywords: microwave; nucleoside; phosphitylation; phosphoramidite; ribulose