Synthesis of labile base protected-modified deoxy and modified ribo nucleosides, corresponding phosphoramidites and supports and their use in high purity oligonucleotide synthesis

Abstract

This invention relates to novel method of synthesis of RNA utilizing N-2-acetyl protected guanine as nucleoside base, nucleosides, succinates, phosphoramidites, corresponding solid supports that are suitable for oligo deoxy nucleosides and RNA oligonucleotide synthesis. Our discovery using N-acetyl protected guanine as nucleoside base protecting group, which is significantly faster base labile protecting group, yet significantly more stable than commonly utilized-2-isobutyryl guanosine is a novel approach to obtain highest purity oligonucleotides. This approach is designed to lead to very high purity and very clean oligonucleotide, after efficient removal of the protecting groups, including acetyl group from guanine and to produce high purity therapeutic grade DNA oligonucleotides, RNA oligonucleotides, diagnostic DNA, diagnostic RNA for microarray platform. The deprotection of acetyl protecting groups of the natural deoxy and ribonucleosides occurs under substantially reduced time in contact with mild deprotection conditions such as mild bases, secondary amines for removal of such groups under such conditions would allows synthesis of various DNA and RNA of highest purity for diagnostics and therapeutic application. This approach is designed to lead to high purity large scale therapeutic grade oligonucleotide chimeras which consist of fluoro sugar modification in conjunction with deoxy nucleosides, ribonucleosides, modified base and modified sugar nucleosides. This approach is further designed to use acetyl guanine protecting group when other bases are sensitive nucleoside, and for use in oligo peptide synthesis and for support bound oligo nucleotides.