Cleavage / Deprotection Reagents

Oligonucleotides synthesized by solid-phase synthesis are bound to a solid-phase support. Therefore, after synthesis, the oligonucleotides are cleaved from the solid-phase support by treatment with a base reagent such as ammonia water or alkylamine. In addition, since protective groups have been introduced to reactive substituents (amino group or hydroxyl group) to prevent their participation in the coupling reaction, deprotection of the protective groups is conducted to complete the synthesis process.

Generally, an amino group of base moiety is protected by an acyl group, a hydroxyl group at the 5' position of the sugar moiety is protected by a DMTr group (dimethoxytrityl group), and a hydroxyl group of phosphoric acid is protected by a cyanoethyl group. The DMTr group at the 5' position of the sugar moiety is removed by an acid and other protecting groups are removed under basic conditions after oligo synthesis. In the case of RNA synthesis, a hydroxyl group at the 2' position of the sugar moiety needs to be protected and a tert-butyldimethylsilyl group (TBDMS group) or the like is used as a protective group. Fluoride ions, such as a TBAF solution, are used for deprotection.