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.