US Patent 11548910 Oligonucleotide production method

The invention provides a novel method for producing an oligonucleotide using a nucleoside or oligonucleotide that is easy to isolate and has high storage stability. The oligonucleotide production method includes a step of subjecting a nucleoside or oligonucleotide having a pseudo solid phase-protecting group in at least one location selected from the group consisting of 2′-position, 3′-position, 5′-position and a nucleobase moiety and having a 5′-hydroxyl group or a 3′-hydroxyl group, to H-phosphonation to convert the 5′-hydroxyl group or the 3′-hydroxyl group into an H-phosphonated form.