A versatile reagent for the synthesis of 5′-phosphorylated, 5′-thiophosphorylated or 5′-phosphoramidate-conjugated oligonucleotides (original) (raw)
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Organic Letters, 2000
H-Phosphonate monomers of 2′-O-(2-methoxyethyl) ribonucleosides have been synthesized. Oxidation of oligonucleotide H-phosphonates has been optimized to allow the synthesis of oligonucleotides containing either 2′-deoxy or 2′-O-(2-methoxyethyl) ribonucleoside residues combined with three different phosphate modifications in the backbone, i.e., phosphodiester (PO), phosphorothioate (PS), and phosphoramidate (PN). Phosphodiester linkages were introduced by oxidation with a cocktail of 0.1 M Et 3 N in CCl 4 /Pyr/H 2 O (5:9:1) without affecting phosphorothioate or phosphoramidate linkages. For the synthesis of phosphoramidate-modified oligonucleotides, N 4-acetyl deoxycytidine-3′-H-phosphonate monomers were used to avoid transamination during the oxidation step.
Tetrahedron, 2006
A general and convenient method for synthesis of modified oligonucleotides by use of new non-nucleoside phosphoramidites is reported. A chiral 1,3-diol backbone of the modifying reagents is generated either from (R)-(+)-a-hydroxy-g-butyrolactone or (R)-(À)pantolactone. Aliphatic amines were acylated with the lactones to give the corresponding N-substituted 2,4-dihydroxybutyramides. After protection of a side chain, if necessary, the diols were converted into phosphoramidites or solid supports suitable for use in oligonucleotide synthesis. The reagents allow single, multiple or combined introduction of various functions (e.g., alkylamine, imidazole and pyrene residues) into synthetic oligonucleotides. The structures of the conjugates were confirmed by MALDI-TOF mass spectrometry.
New Alkyne and Amine Linkers for Versatile Multiple Conjugation of Oligonucleotides
ACS Omega, 2020
Oligonucleotide (ON) conjugates are increasingly important tools for various molecular diagnostics, nanotechnological applications, and for the development of nucleic acid-based therapies. Multiple labeling of ONs can further equip ON-conjugates and provide improved or additional tailored properties. Typically, the preparation of ON multiconjugates involves additional synthetic steps and/or manipulations in post-ON assembly. This report describes the simplified methodology allowing for multiple labeling of ONs on a solid support and is compatible with phosphodiester as well as phosphorothioate (PS) ONs. The current approach utilizes two novel alkyneand amino-functionalized linker phosphoramidites that can be readily synthesized from a common aminodiol intermediate in three steps. The combination of new linkers provides orthogonal functionalities, which allow for multiple attachments of similar or varied moieties. The linkers are incorporated into ONs during automated solid-phase ON synthesis, and the conjugation with functional entities is achieved by either amide bond formation or by copper(I)-catalyzed azide−alkyne cycloaddition (CuAAC). The versatility of the approach is demonstrated by the synthesis of 5′-site ON multiconjugates with small molecules, peptides, and fatty acids as well as in the preparation of an internal peptide−ON conjugate.
A New Approach to Oligonucleotide N3′⇉P5′ Phosphoramidate Building Blocks
Nucleosides, Nucleotides and Nucleic Acids, 2005
A new synthetic approach to 5 0 -phosphoramidites of 3 0 -aminonucleosides was developed. The methodology relies upon the use of 3 0 -amino-2 0 ,3 0 -dideoxynucleosides as the key starting materials. The final products were obtained in high yields via 2-3step processes using selective introduction of orthogonal protective groups to the 3 0 -aminonucleoside sugar and base moieties.
A facile route to 3′-modified oligonucleotides
Bioorganic & Medicinal Chemistry Letters, 1997
We describe an easy method for the solid phase synthesis of 3'-modified oligonucleotides. The general synthetic scheme involves the immobilisation of 5'-DMTr-T to CPG via a sulfonate linker, oligonucleotide synthesis and subsequent basic Ireatment to afford 3"-modified oligonucleotides containing a 2,3"-anhydronucleoside moiety. These compounds can be readily transformed into 3'-substitutod ofigonucleotides such as 3'-deoxy-3'-azido species. © 1997 Elsevier Science Ltd.
Nucleic Acids Research, 1998
A new activator for the coupling of phosphoramidites to the 5′-hydroxyl group during oligonucleotide synthesis is introduced. The observed time to complete coupling is twice as fast with 4,5-dicyanoimidazole (DCI) as the activator, compared with 1H-tetrazole. The effectiveness of DCI is thought to be based on its nucleophilicity. DCI is soluble in acetonitrile up to 1.1 M at room temperature and can be used as the sole coupling activator during routine automated solid phase synthesis of oligonucleotides. The addition of 0.1 M N-methylimidazole to 0.45 M 1H-tetrazole also results in higher product yields during oligonucleotide synthesis than observed with 1H-tetrazole alone.
[Functionalization of oligonucleotides containing internucleotide phosphoamide bonds]
Bioorganicheskaia khimiia
A new method for functionalization of oligonucleotides by addition of aminoalkyl derivatives to the intermolecular phosphorus atom of the oligonucleotide N3'-P5' phosphoramidate bond in the presence of triphenylphosphine, 4-dimethylaminopyridine, and 2,2'-dipyridyl disulfide was suggested. The reaction proceeded with both low-molecular alkylamines (1,6-diaminohexane or N,N-dimethyl-1,3-diaminopropane) and a ligand in minor groove containing a aminoalkyl group.
Molecules, 2017
Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) ligands represent an emerging approach to antisense therapy. Our current generation of GalNAc-ASO conjugates link the GalNAc to the 5′-terminus of the ASO. The conjugation reaction can be accomplished using solution-phase or solid-phase techniques. Here we show a direct comparison of a solution-phase and a solid-phase conjugation strategy. The solution-phase approach, using amine-pentafluorophenyl (PFP) ester coupling, is higher yielding and gives material of slightly higher purity, but requires several additional unit operations and longer production time. The solid-phase approach, using a protected GalNAc ligand phosphoramidite, is more expedient, but results in lower yield and purity. Both strategies efficiently deliver conjugated material in excellent purity.