Method for producing oligonucleotide having phosphorothioated site

Abstract

A method including obtaining a phosphite form or a phosphorous acid diester form by coupling a nucleoside, nucleotide or oligonucleotide wherein a 5′-hydroxy group is not protected, and other group is optionally protected by a protecting group used for nucleic acid synthesis or bonded to a solid phase carrier, and a nucleoside, nucleotide or oligonucleotide wherein a 3′-hydroxy group or a 3′-amino group is modified by a method for forming a phosphite form or a phosphorous acid diester form, and other group is optionally protected by a protecting group used for nucleic acid synthesis in the presence of an antioxidant is useful for producing an oligonucleotide having a phosphorothioated site.

Dependencies are inferred from the claim text.