NOVEL NON-NUCLEOSIDIC PHOSPHORAMIDITE BUILDING-BLOCKS FOR VERSATILE FUNCTIONALIZATION OF OLIGONUCLEOTIDES AT PRIMARY HYDROXY-GROUPS

Synthesis of two non-nucleosidic phosphoramidite building blocks, 1a, b, that enable attachment of various tether groups to oligonucleotides at their 5'-terminus (or 1'-OH of 3'-deoxypsico-nucleoside units) is described. Introduction of these linkers during the oligonucleotide as sembly on a solid support, and their subsequent derivatization upon de protection, afforded amino-, carboxy-, and sulfanyl-alkyl-thethered ol igonucleotides.