A general and efficient approach to synthesize the phosphoramidites of 5′-¹⁸O labeled purine nucleosides

Abstract

5′-¹⁸O labeled RNA oligos are important probes to investigate the mechanism of 2′-O-transphosphorylation reactions. Here we describe a general and efficient synthetic approach to the phosphoramidite derivatives of 5′-¹⁸O labeled nucleosides starting from the corresponding commercially available 5′-O-DMT protected nucleosides. Using this method, we prepared 5′-¹⁸O-guanosine phosphoramidite in 8 steps (13.2% overall yield), 5′-¹⁸O-adenosine phosphoramidite in 9 steps (10.1% overall yield) and 5′-¹⁸O-2′-deoxyguanosine phosphoramidite in 6 steps (12.8% overall yield). These 5′-¹⁸O labeled phosphoramidites can be incorporated into RNA oligos by solid phase synthesis for determination of heavy atom isotope effects in RNA 2′-O-transphosphorylation reactions.

Keywords:

• Isotopic substitution
• ¹⁸O labeled nucleoside phosphoramidite
• ¹⁸O labeled RNA
• kinetic isotope effect
• 2′-O-transphosphorylation

Acknowledgments

We thank Michael Disare and Allison Brink for helpful discussions and critical comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Institutes of Health (GM127100 to M.E.H and GM131568 to J.A.P.).