Synthesis of a cholesteryl-HEG phosphoramidite derivative and its application to lipid-conjugates of the anti-HIV 5'TGGGAG³' Hotoda's sequence.

A novel phosphoramidite derivative of cholesterol, with an ether-linked hexaethylene glycol (HEG) spacer arm, has been obtained through simple and reproducible solid phase modified oligonucleotide synthesis manipulations. This building block and the known phosphoramidite derivative of 3b-(2-hydroxyethoxy)cholesterol have been exploited in standard oligonucleotide synthesis protocols for the preparation of 5'- conjugates of the G-quadruplex-forming 5'TGGGAG³' oligomer, known as the Hotoda's sequence, to produce new potential anti-HIV agents.