Abstract: The purpose of the present invention is to reduce the strong hepatotoxicity of antisense nucleic acids that incorporate an artificial nucleobase (e.g., LNA). The present invention provides a bridged antisense nucleic acid for which antisense nucleic acid-induced toxicity is reduced by the supplemental addition to the wing region of a specific artificial nucleobase (e.g., MCA), while retaining the sequence of the antisense nucleic acid and the number of artificial nucleobases (e.g., LNA). The present invention also provides an antisense nucleic acid drug having a remarkably-reduced hepatotoxicity.

Abstract: Provided is an artificial nucleoside or artificial nucleotide capable of composing an artificial oligonucleotide having superior nuclease resistance. The artificial nucleoside or artificial nucleotide is a compound represented by formula (I) or a salt thereof (wherein, Bx represents a pyrimidine base or purine base, R1, R2, R3 and R4 represent hydrogen atoms, C1-6 alkyl groups or the like, Y represents NR5R6 (wherein, R5 and R6, independently of each other, represent a hydrogen atom, C1-6 alkyl group or the like, or R5 and R6, together with a nitrogen atom bound thereto, form a 3- to 11-membered nitrogen-containing non-aromatic heterocyclic group) or an optionally substituted C2-9 aromatic heterocyclic group, Z1 and Z2 represent hydrogen atoms, hydroxyl group-protecting groups, phosphorous-containing groups or the like, and n represents an integer of 1 to 3).

Abstract: Provided is an artificial nucleoside or artificial nucleotide capable of composing an artificial oligonucleotide having superior nuclease resistance. The artificial nucleoside or artificial nucleotide is a compound represented by formula (I) or a salt thereof (wherein, Bx represents a pyrimidine base or purine base, R1, R2, R3 and R4 represent hydrogen atoms, C1-6 alkyl groups or the like, Y represents NR5R6 (wherein, R5 and R6, independently of each other, represent a hydrogen atom, C1-6 alkyl group or the like, or R5 and R6, together with a nitrogen atom bound thereto, form a 3- to 11-membered nitrogen-containing non-aromatic heterocyclic group) or an optionally substituted C2-9 aromatic heterocyclic group, Z1 and Z2 represent hydrogen atoms, hydroxyl group-protecting groups, phosphorous-containing groups or the like, and n represents an integer of 1 to 3).

Abstract: The present invention relates to a production method and a production intermediate for guanosine-3?,5?-bisdiphosphate.

Abstract: The invention provides an antisense oligonucleotide reduced in toxicity. The antisense oligonucleotide has a central region, a 5?-side region and a 3?-side region, wherein the central region has a nucleotide (2?-3? bridged nucleotide) in which the 2?-position and the 3?-position of a sugar moiety are bridged and/or a non-bridged nucleotide (3?-position-modified non-bridged nucleotide) having a substituent at the 3?-position.

Abstract: Provided is a ribonucleoside derivative represented by General Formula (I): (wherein R1 represents a hydrogen atom or the like, R2 represents a hydrogen atom or the like, R3 represents a methyl group or the like, and B represents a nucleic acid base residue optionally having a protecting group or a modifying group). An RNA containing this ribonucleoside derivative shows excellent hybridization ability and resistance to nuclease.

Abstract: Methods of synthesizing nucleic acid oligomers on a solid-phase support having a 3?-end nucleoside unit introduced thereon-as represented by formula II: wherein of formula II represents a 2?-deoxyribonucleoside or its N-protected derivative, the substituent —O—(R1)Si(R2)—(C6H3R6)—(CH2)n—O—P(OR3)XO)—(CH2)n is attached at the 3? position of the sugar moiety of the nucleoside substituent; each of R1 and R2 is an alkyl or optionally substituted aryl group, wherein the optionally substituted aryl group has a substituent selected from the group consisting of C1-4 alkyl, nitro, cyano, halo and methoxyl; R3 is a protecting group; X is S or O; R7 is H or 4,4?-dimethoxytrityl; each n is an integer of from 1 to 5; and the solid-phase support has hydroxyl groups on its surface.

Abstract: The purpose of the present invention is to provide a compound that specifically binds to the base sequence of a double-stranded nucleic acid molecule. The compound can reduce the electrochemical signal/noise ratio (S/N) in electrochemical detection, and as a result, the detection sensitivity (precision) will be greatly improved so as to enable the determination of an ultratrace amount of nucleic acid molecule.

Abstract: To provide an oligonucleotide derivative that can be used without a problem of falling of a DNA probe from a support. The oligonucleotide derivative of the present invention is represented by the following General Formula (1). The oligonucleotide derivative of the present invention can be used in a DNA chip, a microarray, and so on and further used in a method of detecting gene and a method of regulating gene expression, for example.

Abstract: A phosphoramidite method for the synthesis of a nucleic acid oligomer without protecting the base moiety characterized in that a 3? or 5? hydroxyl group of a nucleotide is reacted with a nucleoside phosphoramidite, a cyclonucleoside phosphoramidite, a 2?-substituted nucleoside phosphoramidite, a 4?-substituted nucleoside phosphoramidite, or a 2?,4?-di-substituted nucleoside phosphoramidite to produce a phosphodiester linkage. The phosphoramidite is contacted with an activator containing both a) hydroxybenzotriazole-1-ol (HOBt), a mono-substituted HOBt, a di-substituted HOBt, or a di-substituted phenol and b) imidazole, tetrazole, benzimidazoletriflate (BIT), 4-ethylthiotetrazole, imidazolium triflate(trifluoromethane sulfonate) or 4,5-dicyanoimidazole.

Abstract: The purpose of the invention is to develop a silyl linker that can be efficiently introduced on a solid-phase support used for the synthesis of nucleic acid oligomers such as DNA. The present invention relates to a silyl linker for use in the solid-phase synthesis of nucleic acid, comprised of a compound of the general formula or its ester or salt: H—(R1)Si(R2)-(C6H4)—CONH-(A)-COOH??(I) wherein each of R1 and R2 is an alkyl or aryl group, and (A) represents a spacer moiety; a 3?-end nucleoside unit having said compound linked via an oxygen atom to the 3-position of a sugar of the nucleoside or its derivative, a solid-phase support having the 3?-end nucleoside unit, and a method for synthesis of nucleic acid oligomer with the use of said solid-phase support.

Abstract: Provided is a ribonucleoside derivative represented by General Formula (I): (wherein R1 represents a hydrogen atom or the like, R2 represents a hydrogen atom or the like, R3 represents a methyl group or the like, and B represents a nucleic acid base residue optionally having a protecting group or a modifying group). An RNA containing this ribonucleoside derivative shows excellent hybridization ability and resistance to nuclease.

Abstract: The purpose of the present invention is to develop a system for efficiently constituting cyanoethyl ethers under mild conditions and probability of the ethers as functional groups for imparting specific functions and to make a contribution to the production of novel functional nucleic acids. The present invention relates to a nucleoside that is represented by the general formula (I) or a nucleotide derived therefrom: wherein X and Y may be the same as or different from each other, and are hydrogen, optionally substituted silyl group, 4-methoxytrityl group, 4,4?-dimethoxytrityl group or a group represented by the general formula (II): wherein R1 and R2 may be the same as or different from each other, representing an alkyl group having 1-7 carbon atoms such as diisopropyl, or they are united with each other to form a ring structure, R3 represents a protective group for a phosphoric acid such as 2-cyanoethyl; and B1 represents an optionally substituted pyrimidine or purine base.

Abstract: The purpose of the invention is to develop a silyl linker that can be efficiently introduced on a solid-phase support used for the synthesis of nucleic acid oligomers such as DNA. The present invention relates to a silyl linker for use in the solid-phase synthesis of nucleic acid, comprised of a compound of the general formula or its ester or salt: H—(R1)Si(R2)—(C6H4)—CONH-(A)-COOH ??(I) wherein each of R1 and R2 is an alkyl or aryl group, and (A) represents a spacer moiety; a 3?-end nucleoside unit having said compound linked via an oxygen atom to the 3-position of a sugar of the nucleoside or its derivative, a solid-phase support having the 3?-end nucleoside unit, and a method for synthesis of nucleic acid oligomer with the use of said solid-phase support.

Abstract: The purpose of the present invention is therefore to provide a method for binding a 3?-end nucleoside unit comprising any base to a hydroxyl group on a solid-phase support under completely the same condition as in DNA chain elongation reaction. The present invention relates to a 3?-end nucleoside unit comprising phosphoramidite that is a compound represented by the following formula: (N)—O—(R1)Si(R2)-(C6H4)—(CH2)n-O—P(OR3)N(R4)(R5)??(I) wherein (N) represents any nucleoside or its derivative, each of R1, R2, R4 and R5 is an alkyl or aryl group, R3 is a phosphate-protecting group, and n is an integer of from 1 to 5; a solid-phase support having said 3?-end nucleoside unit; and a method for the synthesis of a nucleic acid oligomer with the use of said solid-phase support.

Abstract: The purpose of the present invention is to develop a system for efficiently constituting cyanoethyl ethers under mild conditions and probability of the ethers as functional groups for imparting specific functions and to make a contribution to the production of novel functional nucleic acids. The present invention relates to a nucleoside that is represented by the general formula (I) or a nucleotide derived therefrom: wherein X and Y may be the same as or different from each other, and are hydrogen, optionally substituted silyl group, 4-methoxytrityl group, 4,4?-dimethoxytrityl group or a group represented by the general formula (II): wherein R1 and R2 may be the same as or different from each other, representing an alkyl group having 1-7 carbon atoms such as diisopropyl, or they are united with each other to form a ring structure, R3 represents a protective group for a phosphoric acid such as 2-cyanoethyl; and B1 represents an optionally substituted pyrimidine or purine base.

Abstract: The purpose of the present invention is to provide a compound that specifically binds to the base sequence of a double-stranded nucleic acid molecule. The compound can reduce the electrochemical signal/noise ratio (S/N) in electrochemical detection, and as a result, the detection sensitivity (precision) will be greatly improved so as to enable the determination of an ultratrace amount of nucleic acid molecule.