Synthesis of Very Short Chain Lysophosphatidyloligodeoxynucleotides

Abstract

Very short chain 5'-O-lysophosphatidyloligonucleotides [5'-O-(1-O-palmitoyl-sn-glycero-3-phosphoryl)oligodeoxynucleotides, (5'-LyPOdNs)] were synthesized following a two-step chemoenzymatic synthesis. 5'-O-(sn-Glycero-3-phosphoryl)oligodeoxynucleotides (5'-GPOdNs) were first prepared by simply using a phosphoramidite of [(4S)-2,2-dimethyl-1,3-dioxolan-4-yl]methanol (1) in a further coupling step after the solid-phase elongation of each desired oligodeoxynucleotide. Next, the regioselective palmitoylation at the C-1 hydroxyl of the glycerol moiety of 5'-GPOdNs was achieved by a lipase-catalyzed transacylation with trifluoroethyl palmitate in organic solvent. Despite of the molecular bulkiness of 5'-GPOdNs, 2-, 3-, and 4-mer 5'-LyPOdNs were prepared by this procedure. Although in very low yield, 5- and 6-mer 5'-LyPOdNs were also obtained by this way.

Synthesis of Nucleosides with 2′‐Fixed Lipid Anchors and Their Behavior in Phospholipid Membranes

“…Further, the lipophilic group may enable nucleic acids to traffic through cell membranes. [4][5][6] In all these cases the lipophilic moiety was attached either to the 5Ј-or 3Ј-OH group of the oligonucleotide by using the corresponding 3Ј-or 5Ј-lipidated nucleosides, respectively, as building blocks in the phosphoramidite method. [1] Membrane passage of lipophilic nucleic acids was recently applied in siRNA-mediated in vivo gene therapy.…”

“…[2,3] The ability of oligonucleotides to permeate cell membranes by the introduction of lipidic structures into the oligonucleotides has been used in the development of antiviral compounds. [4][5][6] In all these cases the lipophilic moiety was attached either to the 5Ј-or 3Ј-OH group of the oligonucleotide by using the corresponding 3Ј-or 5Ј-lipidated nucleosides, respectively, as building blocks in the phosphoramidite method. In order to study the effect of the position of the lipidated nucleotide in an oligonucleotide strand and also the position within the lipophilic nucleotide itself (positional screening) it is necessary to develop nucleosides in which both the 3Ј-and 5Ј-posi-tions are free.…”

Oligonucleotides Conjugated to Natural Lipids: Synthesis of Phosphatidyl-Anchored Antisense Oligonucleotides

“…So, 5′- O -glycerophosphoryloligonucleotides (5′-GPODNs) were first prepared on solid phase by phosphoramidite chemistry and, in a subsequent step, acylation at the glycerol moiety was performed in organic solvent by a lipase-catalyzed transacylation with activated fatty acid esters. Although some short-chain lysophosphatidyloligonucleotides (but not the phosphatidyl ones) were actually prepared by this route, the extension of the synthetic method to prepare this kind of lipid–ODNs longer than 6-mer was impracticable …”

“…Some years ago, aiming to overcome the above drawbacks, we considered the possibility of preparing phosphatidyl-like conjugates of oligonucleotides 17 by exploiting a two-step chemoenzymatic strategy we had previously developed for preparing lipid-conjugates of deoxyribo-and ribonucleosides as well. 18 So, 5′-O-glycerophosphoryloligonucleotides (5′-GPODNs) were first prepared on solid phase by phosphoramidite chemistry and, in a subsequent step, acylation at the glycerol moiety was performed in organic solvent by a lipasecatalyzed transacylation with activated fatty acid esters.…”

Nucleosides with 5′‐Fixed Lipid Groups – Synthesis and Anchoring in Lipid Membranes

“…[24] The lipophilic moiety is believed to improve the activity because of improved membrane passage and thus cellular uptake. Other very important features of lipophilic oligonucleotides are the ability to permeate cell membranes causing antiviral activity [25] and the property of facilitating membrane passage of siRNA, which was achieved by the introduction of lipid anchors, such as cholesteryl or dialkylaminophenyl groups into the 5Јand 3Ј-end of the oligonucleotide chain. [26,27] In continuation of our studies on lipophilic nucleosides and oligonucleotides, we report here the synthesis of new lipophilic nucleosides 1, where one or two lipophilic moieties are connected to the 5Ј-position as phosphate (X = PO 4 ) or as amine (X = NR).…”