A solid support (3) and a non-nucleosidic phosphoramidite building block (41, both containing a thioester bond in their structure, were synthesized. They were used in the preparation of oligonucleotides tethered to an imidazole group at their 3'-or 5'-terminus, as well as at the 1 '-position of nonterminal 3'-deoxypsicothymidine units. The desired functional groups were introduced during the deprotection of the oligonucleotide by using ...
