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 3 beta-(2-hydroxyethoxy) cholesterol have been exploited in standard oligonucleotide synthesis protocols for the preparation of 5'-conjugates of the G-quadruplex-forming (5)'TGGGAG(3)' oligomer, known as the Hotoda's sequence, to produce new potential anti-HIV agents.