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Characterization of high molecular weight impurities in synthetic phosphorothioate oligonucleotides.
Phosphorothioate oligonucleotides manufactured by standard phosphoramidite techniques using 2'-deoxyadenosine- or 2'-O-(2-methoxyethyl)-5-methylcytosine-loaded solid supports contain branched impurities, but these impurities are not produced when a universal, non-nucleoside derivatized support is used. Expand
Synthesis of High-Quality Antisense Drugs. Addition of Acrylonitrile to Phosphorothioate Oligonucleotides: Adduct Characterization and Avoidance
It is demonstrated that the acrylonitrile (AN) generated during the ammonolysis step of oligonucleotide manufacture selectively adds to thymine residue present in ISIS 2302 to give a full-lengthExpand
Formation of 4,4'-dimethoxytrityl-C-phosphonate oligonucleotides.
Incomplete sulfurization during solid-phase synthesis of phosphorothioate oligonucleotides using phosphoramidite chemistry was identified as the cause of formation of two new classes ofExpand
Controlled Detritylation of Antisense Oligonucleotides
The last chemical step in standard oligonucleotide synthesis, the acid-catalyzed removal of 4,4‘-dimethoxytrityl (DMTr) protecting groups from the 5‘-terminus of oligonucleotides is accompanied byExpand
UnyLinker: An Efficient and Scaleable Synthesis of Oligonucleotides Utilizing a Universal Linker Molecule: A Novel Approach To Enhance the Purity of Drugs
A novel universal linker (UnyLinker) molecule which has a conformationally rigid and chemically stable bridge head ring oxygen atom carrying a conventional 4,4′-dimethoxytrityl (DMT) and succinylExpand
Synthesis of an antisense oligonucleotide targeted against C-raf kinase: efficient oligonucleotide synthesis without chlorinated solvents.
It is demonstrated that a solution of dichloroacetic acid in toluene removes dimethoxytrityl groups from the 5'-terminus of an antisense phosphorothioate oligodeoxyribonucleotide (ISISExpand
Solid Phase Synthesis of Phosphorothioate Oligonucleotides Utilizing Diethyldithiocarbonate Disulfide (DDD) as an Efficient Sulfur Transfer Reagent
Abstract Diethyldithiodicarbonate (DDD), a cheap and easily prepared compound, is found to be a rapid and efficient sulfurizing reagent in solid phase synthesis of phosphorothioateExpand
Pyridinium Trifluoroacetate/N-Methylimidazole as an Efficient Activator for Oligonucleotide Synthesis via the Phosphoramidite Method
A new activator is reported for coupling phosphoramidites to a free 5‘-hydroxyl group during oligonucleotide synthesis. Pyridinium trifluoroacetate/N-methyl imidazole is a remarkably efficientExpand
Applications of green chemistry in the manufacture of oligonucleotide drugs
We have modified the current phosphoramidite-based, solid-phase synthesis of antisense oligonucleotides to accommodate principles of green chemistry. In this article, we summarize key accomplishmentsExpand
Influence of Diastereomeric Ratios of Deoxyribonucleoside Phosphoramidites on the Synthesis of Phosphorothioate Oligonucleotides
Abstract Extensive investigations on the influence of diastereomeric ratios of deoxyribonucleoside phosphoramidites on stereo-reproducibility of solid phase synthesis of phosphorothioateExpand