Abstract: Bicyclonucleoside analogues which exhibit anti-AIDS activity and intermediates to produce oligonucleotide analogues which have anti-sense or anti-gene activity as well as in vivo stability. Compounds of the following formula (1) or their pharmaceutically acceptable salts. wherein R1 represents a hydrogen atom or a protecting group for a hydroxy group, R2 represents an azido group or an optionally protected amino group or the like, B represents a purin-9-yl or a 2-oxo-1,2-dihydropyrimidin-1-yl group, which are optionally substituted with substituents selected from the group consisting of a halogen atom, an alkyl group having 1–6 carbon atoms, a hydroxy group, a mercapto group and an amino group.

Abstract: Compounds of the following general formula (1) and salts thereof: where A represents a direct bond, an alkylene group having 1 to 4 carbon atoms, etc.; B represents an aromatic heterocyclic group which may have a substituent, etc.; R1, R2, R3 and R4 each represent a hydrogen atom, a protective group for an amino group, a protective group for a hydroxyl group, a phosphate group, or —P(R7)R8 [where R7 and R8 each represent a hydroxyl group, a protected hydroxyl group, a mercapto group, a protected mercapto group, etc.]. These compounds are useful as oligonucleotide analogues useful for the antisense method, and as nucleoside analogues for producing their intermediates.

Abstract: Nucleoside analogues expressed by the following general formula where B represents an aromatic base having carbonyl oxygen at the 2-position, or a 2-hydroxyphenyl group, or oligonucleotide derivatives containing one or more of the nucleoside analogues are provided. The oligonucleotide derivatives are triplex-forming oligonucleotide derivatives which bind specifically to target double-stranded DNA with high affinity in the antigene method to form triplexes, and can thereby control and inhibit the expression of relevant genes efficiently, and which show high resistance to nucleases.

Abstract: Compounds of the following general formula (1) and salts thereof: where A represents an alkylene group having 1 to 2 carbon atoms, etc.; B represents an aromatic heterocyclic group which may have a substituent, etc.; R1 and R2 each represent a hydrogen atom, a protective group for a hydroxyl group for synthesis of nucleic acid, a phosphate group, or —P(R4)R5 [where R4 and R5 are the same or different, and each represent a hydroxyl group, a hydroxyl group protected with a protective group for synthesis of nucleic acid, a mercapto group, a mercapto group protected with a protective group for synthesis of nucleic acid, etc.]; and R3 represents a hydrogen atom, a halogen atom, a hydroxyl group, a hydroxyl group protected with a protective group for synthesis of nucleic acid, etc. These compounds are useful for producing oligonucleotide analogues useful for the antisense method, antigene method, etc., and for producing their intermediates.

Abstract: An antisense oligonucleotide derivative against HCV is provided which contains one or more nucleotide analogue units having a modified sugar portion and represented by the following general formula where B denotes a pyrimidine or purine nucleic acid base or an analogue thereof. The derivative of the present invention is an antisense against hepatitis C virus (HCV) gene, binds to HCV-RNA with high affinity within cells, can control and inhibit the expression of its gene with high efficiency, and shows high resistance to nucleases. The BNA antisense oligonucleotide of the present invention is also effective in an antisense method targeting HCV, no matter what secondary structures, such as loops or stems, in a target RNA nucleic acid are.

Abstract: Nucleoside analogues expressed by the following general formula 1

Abstract: An oligo- or polynucleotide analogue having one or more structures of the general formula where B is a pyrimidine or purine nucleic acid base, or an analogue thereof, is disclosed. The use of this analogue provides an oligonucleotide analogue antisense molecule, which is minimally hydrolyzable with an enzyme in vivo, has a high sense strand binding ability, and is easily synthesized.

Abstract: Bicyclonucleoside analogues which exhibit anti-AIDS activity and intermediates to produce oligonucleotide analogues which have anti-sense or anti-gene activity as well as in vivo stability. Compounds of the following formula (1) or their pharmaceutically acceptable salts.

Abstract: An oligo- or polynucleotide analogue having one or more structures of the general formula 1

Abstract: An oligo- or polynucleotide analogue having one or more structures of the general formula where B is a pyrimidine or purine nucleic acid base, or an analogue thereof, is disclosed. The use of this analogue provides an oligonucleotide analogue antisense molecule, which is minimally hydrolyzable with an enzyme in vivo, has a high sense strand binding ability, and is easily synthesized.