Andrei P. Guzaev

A novel phosphate protection for oligonucleotide synthesis: the 2-[(1-naphthyl)carbamoyloxy]ethyl (NCE) group

Abstract The utility of the 2-(arylcarbamoyloxy)ethyl group for protection of internucleosidic phosphate linkages in oligonucleotide synthesis was studied. Of the three protecting groups tested, the 2-[(1-naphthyl)carbamoyloxy]ethyl demonstrated high coupling yields, favorable deprotection kinetics and the highest hydrolytic stability of the thymidine phosphoramidite building block. The mechanism of deprotection was confirmed by deprotecting a model phosphate triester and synthetic dodecathymidylate.

Novel reagents for terminal phosphorylation and thiophosphorylation of synthetic oligonucleotides

Abstract Two novel phosphoramidite building blocks and a solid support that allow an efficient solid-phase phosphorylation or thiophosphorylation of synthetic oligonucleotides were developed. The utility of these synthetic tools was demonstrated in the preparation of 5′- or 3′-thiophosphorylated oligonucleotides, which were subsequently labeled at the termini with fluorescent reporters.

A novel protecting strategy for internucleosidic phosphate and phosphorothioate groups.

The utility of 2–(N–isopropyl–N–anisoylamino)ethyl group for protection of internucleosidic phosphate linkages in oligonucleotide synthesis was studied. The group demonstrated high coupling yields, favorable deprotection kinetics and a high hydrolytic stability of phosphoramidite building blocks. The mechanism of deprotection was established using a model phosphate triester.

Synthesis of Chimerical Oligonucleotides Containing Internucleosidic Phosphodiester and S-Pivaloyl Mercaptoethyl Phosphotriester Linkages

Abstract Novel oligonucleotide analogs that bear phosphodiester and bioreversible S-pivaloyl 2-mercaptoethyl (SPME) phosphate triester internucleosidic linkages and their thioate analogs are described. Their synthesis involves new methodology for the deprotection of base-labile oligonucleotides.

Synthesis of Fully Protected Nucleoside- Folic Acid Conjugated Phosphoramidites and Their Incorporation into Antisense Oligonuleotides

Abstract A novel synthesis of the nucleoside-folic acid conjugates has been accomplished. This approach allowed us to synthesize several analogs, which were converted to phosphoramidites and successfully incorporated into therapeutically active antisense oligonucleotides.

Synthesis of Oligonucleotide Conjugates with the Aid of N-Chloroacetamidohexyl Phosphoramidite Reagent

Abstract A novel phosphoramidite building block derived from N-chloroacetyl-6-aminohexanol is attached at the 5′-terminus on the last step of oligonucleotide synthesis. Postsynthetic treatment of support-bound modified oligonucleotides with a variety of amines and mercaptanes affords oligonucleotide conjugates in a high yield.

EFFICIENT SYNTHESIS OF OLIGONUCLEOTIDE-PEPTIDE CONJUGATES ON LARGE SCALE

The conjugation of oligonucleotide phosphorothioates with antennapedia peptide was studied in detail to allow efficient preparation of the conjugates on up to 15 μmol scale. Under optimized conditions, the use of oligonucleotides and the peptide in an equimolecular ratio gave the desired conjugates in more than 60% isolated yield.

SYNTHESIS OF CHIMERIC OLIGONUCLEOTIDES CONTAINING INTERNUCLEOSIDIC PHOSPHODIESTER AND S–PIVALOYLTHIOETHYL PHOSPHOTRIESTER RESIDUES

Novel oligonucleotide analogs that bear phosphodiester and bioreversible Õ–pivaloyl 2–mercaptoethyl (SPME) phosphate triester internucleosidic linkages are described. Their synthesis employs a novel methodology of oligonucleotide deprotection under mild, non-aqueous conditions.

Use of [4,6-Di-14C]-5′-DMT-thymidine Phosphoramidite Reagent for the Radiolabeling of Synthetic Oligonucleotides

Abstract A novel synthesis of 5′-radiolabeled oligonucleotides is described. The labeling is carried out by the phosphoramidite method with the aid of building block 1. The feasibility of the method is demonstrated by preparation of 5′-radiolabeled 3′-phosphorylated dodecathymidylate phosphorothioate.