EP1661905B9 — Novel artificial nucleic acids of n-o bond crosslinkage type

USPTO Abstract

It is intended to provide oligonucleotide analogs usable in, for exmaple, the antisense method which are highly tolerant to enzymes, have a strong and selective binding affinity for a single-stranded RNA and also are highly capable of forming a triple-strand in a double-stranded DNA, and nucleoside analogs useful for producing the same. Namely, a nucleoside analog which is a compound represented by the following general formula (I) or its salt and an oligonucleotide analog containing one or more of the same: wherein Base represents an optionally substituted aromatic heterocyclic group, etc.: R 1 , R 2 and R 3 represent each a hydrogen atom, an amino-protecting group, a hydroyl-protecting group, a phosphate group or -P (R 4 )R 5 [wherein R 4 and R 5 represent each a hydroxyl group, a protecting group, an optionally protected mercapto group, etc,]; m is from 0 to 2; and n is from 1 to 3.