The present invention provides a method for removing a 2-cyanoethoxymethyl (CEM) group, which substitutes the 2′-hydroxyl group of each ribose of an oligonucleic acid derivative, with good reproducibility and high efficiency. The present invention further provides a method for producing an oligonucleic acid derivative represented by the following general formula (11), characterized by using a sulfoxide-based solvent or an amide-based solvent or a mixture thereof as a reaction solvent in the step of removing a protecting group, which protects the 2′-hydroxyl group of each ribose of an oligonucleic acid derivative represented by the following general formula (10) by allowing TBAF to act on the oligonucleic acid derivative.
本发明提供了一种去除2-
氰乙氧甲基(C
EM)基团的方法,该基团替代了寡核苷酸衍
生物中每个
核糖的2'-羟基,具有良好的重现性和高效性。本发明进一步提供了一种通过在去除保护基的步骤中使用亚砜基溶剂或酰胺基溶剂或其混合物作为反应溶剂,使TBAF作用于以下通式(10)所表示的寡核苷酸衍
生物的每个
核糖的2'-羟基的保护基,从而制备以下通式(11)所表示的寡核苷酸衍
生物的方法。