Search

A complete series of the 2 '-5 ' and 3 '-5 ' regioisomeric types of r(ApA) and 2 '-d(ApA) analogues with the α-hydroxy-phosphonate C3 '-O-P-CH(OH)-C4 '' internucleotide linkage, isopolar but non-isosteric with the phosphodiester one, were synthesized and their hybridization properties with polyU studied. Due to the chirality on the 5 '-carbon atom of the modified internucleotide linkage bearing phosphorus and hydroxy moieties, each regioisomeric type of ApA dimer is split into epimeric pairs. To examine the role of the 5 '-hydroxyl of the α-hydroxy-phosphonate moiety during hybridization, the appropriate r(ApA) analogues with 3 '(2 ')-O-P-CH2-C4 '' linkage lacking the 5 '-hydroxyl were synthesized. Nuclear magnetic resonance (NMR) spectroscopy study on the conformation of the modified sugar-phosphate backbone, along with the hybridization measurements, revealed remarkable differences in the stability of complexes with polyU, depending on the 5 '-carbon atom configuration. Potential usefulness of the α-hydroxy-phosphonate linkage in modified oligoribonucleotides is discussed. [ABSTRACT FROM AUTHOR]

Retroviral integrase participates in two catalytic reactions, which require interactions with the two ends of the viral DNA in the 3'processing reaction, and with a targeted host DNA in the strand transfer reaction. The 3'-hydroxyl group of 2'-deoxyadenosine resulting from the specific removing of GT dinucleotide from the viral DNA in the processing reaction provides the attachment site for the host DNA in a transesterification reaction. We synthesized oligonucleotides (ONs) of various lengths that mimic the processed HIV-1 U5 terminus of the proviral long terminal repeat (LTR) and are ended by 2'-deoxyadenosine containing a 3'-O-phosphonomethyl group. The duplex stability of phosphonomethyl ONs was increased by covalent linkage of the modified strand with its complementary strand by a triethylene glycol loop (TEG). Modified ONs containing up to 10 bases inhibited in vitro the strand transfer reaction catalyzed by HIV-1 integrase at nanomolar concentrations. [ABSTRACT FROM AUTHOR]

The present work relates to the synthesis of pyrrolidine nucleoside analogs. Starting from malic acid, we have elaborated a high-yield synthesis of racemic and enantiomeric N -protected 3-pyrrolidinols and their O -mesyl derivatives as key compounds for alkylations of purine and pyrimidine nucleobases. On varying base and solvent, we have found conditions providing both satisfactory N -/ O -regioisomeric ratio and acceptable yield for pyrimidine compounds. [ABSTRACT FROM AUTHOR]

An unique set of 5′-O- and 3′-O-phosphonomethyl derivatives of four natural 2′-deoxyribonucleosides, 1-(2-deoxy-β-D-threo-pentofuranosyl)thymine, 5′-O- and 2′-O-phosphonomethyl derivatives of 1-(3-deoxy-β-D-erythro-pentofuranosyl)thymine, and 1-(3-deoxy-β-D-threo-pentofuranosyl)thymine has been synthesized as a pool of monomers for the synthesis of modified oligonucleotides. The phosphonate moiety was protected with 4-methoxy-1-oxido-2-pyridylmethyl ester group, serving also as an intramolecular catalyst in the coupling step. [ABSTRACT FROM AUTHOR]

This work deals with isopolar, phosphonate-based nucleotide analogues containing a bridging P-C bond instead of the ester P-O linkage. Specifically, starting from activated derivatives 1, 2, and 3, a simple process for preparation of mixtures of short oligomers and their analyses were elaborated. [ABSTRACT FROM AUTHOR]

Adenine-based, regioisomeric nucleoside phosphonates with ribo, xylo and arabino configuration were synthesized in the protected form suitable for the phosphotriester-like, solid-phase synthesis of oligonucleotides. Phosphonate moiety was protected by 4-methoxy-1-oxido-2-picolyl group and the furanose hydroxyl by the dimethoxytrityl group. [ABSTRACT FROM AUTHOR]

The synthesis of monomers (S)-1, (R)-1 and 2 derived from (5′S)-, (5′R)-2′-deoxythymidine-5′-C-phosphonic acids and 2′,5′-dideoxythymidine-5′-C-phosphonic acids was elaborated. The protection of the 5′-hydroxyl by the methoxycarbonyl group was a key step of the synthesis. Prepared monomers were used for the solid-phase assembly of several types oligothymidylate 15-mers (S)-3, (S)-4, (S)-5, (R)-4 and (R)-5 containing the chiral 3′-O-P-CH(OH)-5″ internucleotide linkage. Their hybridization properties with dA15 and rA15 were studied as well as their resistance against nuclease cleavage. [ABSTRACT FROM AUTHOR]

Discusses a study on the hybridization of 4'-branched oligonucleotides. Preparation of 4'-Modified monomers in spite of chemical difficulties and significant decomposition of the compound during the key reaction steps; Details of the enzymatic resistance of the oligonucleotides; Measurement of the nuclear magnetic resonance spectra.

The recently described epimeric nucleosidyl-5′-C-phosphonates (α-hydroxyphosphonates) represent novel nucleotide analogues that can be incorporated into chimeric oligonucleotides by the phosphotriester condensation method. In order to prepare suitable protected monomer(s) we have studied condensation reaction between protected 2′-deoxythymidine and 2′-deoxythymidinyl-5′-C-phosphonate, both as model compounds, in dependence on the nature of the 5′-hydroxyl protecting group. We have found that the O-acetyl group is unstable in the presence of TPSCl or MSNT used as condensing agents for activation of the phosphorus moiety. This instability negatively influences the scope of the condensation process. On the other hand, introduction of the O-methoxycarbonyl group gave excellent results. The O-methoxycarbonyl group does not participate in the condensation process, and its quantitative introduction into the nucleotide analogues is accomplished using a novel acylating agent, methoxycarbonyl tetrazole. [ABSTRACT FROM AUTHOR]

A series of novel, unusual type of acyclic phosphonate-based nucleotide analogues related to well-known antivirals (PMEA and HPMPA) was synthesized using easily available synthon. These compounds, which are distinguished for the presence of phosphonomethyl acetal linkage, form a group of derivatives that contribute to the understanding of structure-activity relationship within the area of acyclic nucleotide analogues. [ABSTRACT FROM AUTHOR]

A novel α- and β-configured pyrrolidine nucleoside phosphonates in adenine series were synthesized from trans-4-hydroxy-L-proline as starting material. d(ApA) analogues were also prepared and studied with respect to their hybridization properties with polyU. [ABSTRACT FROM AUTHOR]