title: 3-(N-tert-butylcarboxamido)-1-propyl and 4-oxopentyl groups for phosphate/thiophosphate protection in oligodeoxyribonucleotide synthesis.
abstract: This unit provides procedures for the preparation of deoxyribonucleoside phosphoramidites and appropriate phosphordiamidite precursors with P(III) protecting groups different than the standard 2-cyanoethyl group. Specifically, these phosphoramidites are functionalized with the 3-(N-tert-butylcarboxamido)-1-propyl or 4-oxopentyl groups. The usefulness of these novel deoxyribonucleoside phosphoramidites in the solid-phase synthesis of a 20-mer DNA oligonucleotide and its phosphorothioated analog is demonstrated. It is also shown that removal of the 3-(N-tert-butylcarboxamido)-1-propyl phosphate/thiophosphate-protecting group from these oligonucleotides is rapidly effected under thermolytic conditions at neutral pH, whereas the 4-oxopentyl group is preferably removed by treatment with pressurized ammonia gas or concentrated ammonium hydroxide at ambient temperature. These detailed methods constitute an economical and alkylation-free approach to large-scale preparations of therapeutic oligonucleotides.
authors.affiliation: Food and Drug Administration, Bethesda, Maryland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wilk
authors.affiliation: Food and Drug Administration, Bethesda, Maryland.
authors.forename: Marcin K
authors.initials: MK
authors.lastname: Chmielewski
authors.affiliation: Food and Drug Administration, Bethesda, Maryland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Grajkowski
authors.affiliation: Food and Drug Administration, Bethesda, Maryland.
authors.forename: Serge L
authors.initials: SL
authors.lastname: Beaucage
authors.affiliation: National Cancer Institute, Frederick, Maryland.
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Phillips
mesh_terms: D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis*; D010755:Organophosphates / Q000737:chemistry*; D009943:Organophosphorus Compounds; D063086:Organothiophosphates / Q000737:chemistry*; D010710:Phosphates
chemical_list: D009838:Oligodeoxyribonucleotides; D010755:Organophosphates; D009943:Organophosphorus Compounds; D063086:Organothiophosphates; D010710:Phosphates; C434331:phosphoramidite; C035638:thiophosphoric acid