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: 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: 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.