Solid phase synthesis of oligoribonucleotides using [formula omitted]-nitrobenzyl protection of 2'-hydroxyl via a phosphotriester approach

Abstract

Oligoribonucleotides with chain length of 6–9 were synthesized on a polystyrene support using o -nitrobenzyl protection of 2'-hydroxyls via phosphotriester method. The condensation reactions between N -acyl-5'- O -monomethoxytrityl-2'- O -( o -nitrobenzyl) nucleoside 3'-( o -chlorophenyl) phosphate and nucleoside bound to the resin using l-mesitylenesulfonyl-3-nitro-1 H -1,2,4-triazole (MSNT) as a condensing agent were examined. It was found that the condensation reaction using MSNT was promoted in the presence of 1-methylimidazole as a catalyst. A mixture of MSNT and 1-methylimidazole was also found to be effective in the condensation reaction involving a dinucleotide with 3'-phosphodiester. The fully protected oligomer were deblocked and purified by chromatography in total yields of 3–21 % based on initial nucleoside bound to the support.