Unit

UNIT 4.27 Large-Scale Preparation of Conjugated Oligonucleoside Phosphorothioates by the High-Efficiency Liquid-Phase (HELP) Method

  1. Gian Maria Bonora

Published Online: 1 OCT 2005

DOI: 10.1002/0471142700.nc0427s22

Current Protocols in Nucleic Acid Chemistry

Current Protocols in Nucleic Acid Chemistry

How to Cite

Bonora, G. M. 2005. Large-Scale Preparation of Conjugated Oligonucleoside Phosphorothioates by the High-Efficiency Liquid-Phase (HELP) Method. Current Protocols in Nucleic Acid Chemistry. 22:4.27:4.27.1–4.27.26.

Author Information

  1. University of Trieste, Trieste, Italy

Publication History

  1. Published Online: 1 OCT 2005
  2. Published Print: SEP 2005

Abstract

A new process for the preparation of large amounts of thioated oligonucleotides in a quasi-classical solution condition is described. This method takes advantage of the use of polyethylene glycol as a soluble, inert support during synthesis. The easy purification of intermediates from a moderate excess of reagents allows very high coupling yields and, consequently, efficient production of the long oligonucleotide sequences required for pharmacological applications. The reaction of properly protected and activated oligonucleotides with high-molecular-weight polyethylene glycols allows a convenient procedure for the postsynthetic conjugation of those biopolymers in solution. The oligonucleotides are modified at the 5′ terminus using a liquid-phase procedure with a linker carrying a terminal primary amino group to enhance its nucleophilic reactivity. The use of N, N′-disuccinimidyl carbonate for the activation of the terminal OH groups of the PEG was preferred.

Keywords:

  • liquid-phase synthesis;
  • polyethylene glycol;
  • oligonucleotide;
  • conjugated;
  • phosphorothioate