Synthesis of a Cholesteryl-HEG Phosphoramidite Derivative and Its Application to Lipid-conjugates of the Anti-HIV (5')TGGGAG(3') 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 3β-(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.