Takahashi Y, Sato K, Wada T. Solid-Phase Synthesis of Boranophosphate/Phosphorothioate/Phosphate Chimeric Oligonucleotides and Their Potential as Antisense Oligonucleotides.
J Org Chem 2021;
87:3895-3909. [PMID:
34908418 PMCID:
PMC8938928 DOI:
10.1021/acs.joc.1c01812]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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In this study, we
successfully synthesized boranophosphate (PB),
phosphorothioate (PS), and phosphate (PO) chimeric oligonucleotides
(ODNs) as a candidate for the antisense oligonucleotides (ASOs). The
PB/PS/PO-ODNs were synthesized utilizing H-boranophosphonate, H-phosphonothioate, and H-phosphonate monomers.
Each monomer was condensed with a hydroxy group to create H-boranophosphonate, H-phosphonothioate,
and H-phosphonate diester linkages, which were oxidized
into PB, PS, and PO linkages in the final stage of the synthesis,
respectively. As for condensation of an H-phosphonothioate
monomer, regulating chemoselectivity was necessary since the monomer
has two nucleophilic centers: S and O atoms. To deal with this problem,
we used phosphonium-type condensing reagents, which could control
the chemoselectivity. In this strategy, we could synthesize PB/PS/PO
oligomers, including a 2′-OMe gapmer-type dodecamer. The physiological
and biological properties of the synthesized chimeric ODNs were also
evaluated. Insights from the evaluation of physiological and biological
properties suggested that the introduction of suitable P-modification and sugar modification at proper sites of ODNs would
control the duplex stability, nuclease resistance, RNase H-inducing
ability, and one base mismatch discrimination ability, which are critical
properties as potent ASOs.
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