Synthesis of n-fmoc protected deoxy nucleosides, ribo nucleosides, modified deoxy and ribo nucleosides, and phosphoramidites, and their use in oligonucleotide synthesis

Abstract

This invention relates to synthesis of novel -N-FMOC protected nucleosides, succinates, phosphoramidites, corresponding solid supports that are suitable for oligo deoxy nucleosides and RNA oligonucleotide synthesis. Our discovery using N-FMOC as nucleoside base protecting group, which is highly base labile protecting group 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 and to produce high purity therapeutic grade DNA oligonucleotides, RNA oligonucleotides, diagnostic DNA, diagnostic RNA for microarray platform. The deprotection of FMOC protecting groups of the natural deoxy and ribonucleosides occurs under very mild deprotection conditions such as mild bases, secondary and tertiary 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 further designed to use FMOC protecting group on various base sensitive nucleoside, and for use in oligo peptide synthesis and for support bound oligo nucleotides. DNA oligonucleotides containing 3'-end dA at the 3′-terminal will be produced using the FMOC-dA-supports would lead to much reduced M−1 deletion sequences, and thereby high purity.