THF Peroxide As a Factor in Generating Desulphurised Products from the Solid-phase Synthesis of Phosphorothioate-modified Oligonucleotides

Overview

Journal RSC Adv

Publisher Royal Society of Chemistry

Specialty Chemistry

Date 2024 Jul 9

PMID 38979452

Authors

Qin Ren

Takashi Osawa

Michiaki Tatsuno

Satoshi Obika

Affiliations

Soon will be listed here.

Abstract

Antisense oligonucleotides (ASOs) are generally obtained chemical synthesis on a solid support and phosphorothioate (PS) modification with a phosphate backbone to increase their stability and activity. However, desulphurised products, in which PS is partially replaced by phosphodiesters, are generally formed during the chemical synthesis of ASO and are difficult to separate from the desired PS-modified ASO by chromatography. Therefore, revealing the unknown factors that cause the formation of desulphurised products and proposing methods to inhibit their formation are highly desirable. In this study, it was found that peroxides in THF, which is used as a solvent for the acetyl capping agent, oxidise phosphite triesters to produce desulphurisation products. The use of THF with antioxidants effectively suppresses the oxidation caused by THF peroxides. Moreover, THF peroxide was found to oxidise phosphoramidites, which are the building blocks of oligonucleotide chemical syntheses, indicating that caution should be taken with the organic solvents used during the synthesis and purification of phosphoramidites.

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