5′-O-Dimethoxytrityl deoxyribonucleoside 3′-O-phosphorbisdiethylamidites were prepared by the selective phosphitylation of 5′-O-dinethoxytrityl deoxyribonucleosides with tris (diethylamino) phosphine in the presence of amino and tetrazole as catalyst. The bisamidites activated by p-nitrophenyltetrazole can be coupled efficiently with 5′-hydroxyl group of nucleoside on a solid support. Oligodeoxyribonucleotides were obtained in high ...
