Timothy A. Riley

An improved method for the synthesis and deprotection of methylphosphonate oligonucleotides.

The methylphosphonate oligonucleotide synthesis methods described here give the desired products in good yield. Superior amounts of product are achieved by modifying both the DNA synthesis program and the reagent to compensate for the unstable methylphosphonite intermediate. Deprotection conditions have also been altered to maximize the recovery of oligonucleotide from DNA synthesis supports and to minimize the amount of base modification. Mass-spectrometry analysis of our oligonucleotides has verified their purity and confirmed the absence of modified bases. When compared to standard DNA synthesis methods, this procedure uses only about one-third the usual amount of monomer. Using these procedures, it should be possible to synthesize reliably methylphosphonate oligonucleotides at 1- and 15-mumol scales.

Anti-BCL2 Phosphorothioate G3139 Clinical Pharmacology: Plasma Levels During Contwous Subcutaneous Infusion by HPLC Assay

Abstract An HPLC assay has been developed to determine plasma levels of G3139 - a 18mer phosphorothioate oligonucleotide currently in Phase I clinical studies. The assay utilizes anion exchange microchromatography, aqueous LiBr gradient elution, and UV absorbance detection. Minimum sensitivity of approximately 0.2 μg/ml plasma, or 35 nM of G3139, has been achieved. Analysis of preliminary clinical samples indicates subcutaneous infusion of G3139 at 2 mg/kg/day gives rise to steady state plasma levels of 1–2 μg/ml.

Diastereoselective Synthesis of 2′-Deoxy and 2′-O-Methyl Dinucleoside (3′ 5′)-Methylphosphonates via Alkoxymagnesium Chloride-Mediated Nucleoside Coupling

Abstract A diastereoselective dinucleoside methylphosphonate synthetic method that features coupling of diastereomerically pure 1,1,1,3,3,3-hexafluoro-2-propyl nucleoside-3′-O-methylphosphonate monomers with 3′-O-protected nucleoside monomers mediated by alkoxymagnesium chloride reagents is described. This synthetic method was found to be diastereospecific in the synthesis of selected 2′-deoxy dinucleoside methyphosphonates and diastereoselective in the synthesis of all sixteen 2′-O-methyl dinucleoside methylphosphonates.