[DNA mimics on the base of pyrrolidine and hydroxyproline]

Tandem intramolecular cyclisation/1,3-aryl shift in N-(4,4-diethoxybutyl)-1-arylmethanimines (Kazan reaction): synthesis of 3-benzylidene-1-pyrrolines

A novel tandem reaction, which transforms N-(4,4-diethoxybutyl)imines to 3-arylidene-1-pyrrolines via intramolecular Mannich reaction/[1,3]-sigmatropic rearrangement of the aryl fragment is described.

[Synthesis and properties of methylene carboxamide mimetics of nucleic acids based on morpholine nucleosides]

Uracyl and adenine containing oligocarboxamide mimetics of nucleic acids based on morpholine nucleosides (MorGly) are synthesized using peptide chemistry methods. Conditions for an analysis of homogeneity of protonated at physiological pH oligomers using a capillary electrophoresis are proposed. Studies of thermostability of complementary complexes formed by MorGly oligomers revealed that melting temperature dramatically depends on heterocyclic base composition (uracyl or adenine). Cooperative interactions realized at junctions in tandem complexes give more contribution to the thermostability in the case of complexes formed by modified oligomers than native oligodeoxyriboadenilates. Adenine containing MorGly oligomers form more stable complexes with poly(U) than native oligodeoxyriboadenilate of the same length. Complexes formed by modified oligomers with polyribonucleotides are more stable in compare with polydeoxyribonucleotide.

Synthesis of two new alkyne-bearing linkers used for the preparation of siRNA for labeling by click chemistry with fluorine-18

Oligonucleotides (ONs) and more particularly siRNAs are promising drugs but their pharmacokinetics and biodistribution are widely unknown. Positron Emission Tomography (PET) using fluorine-18 is a suitable technique to quantify these biological processes. Click chemistry (Huisgen cycloaddition) is the current method for labeling siRNA. In order to study the influence of a linker bearing by [(18)F] labeled ONs, on the in vivo pharmacokinetic and metabolism, we have developed two modified ONs by two new linkers. Here we report the synthesis of two alkyne-bearing linkers, the incorporation onto a ONs and the conjugation by click chemistry with a [(18)F] prosthetic group.

Pyrrolidinyl peptide nucleic acid homologues: effect of ring size on hybridization properties

The effect of ring size of four- to six-membered cyclic β-amino acid on the hybridization properties of pyrrolidinyl peptide nucleic acid with an alternating α/β peptide backbone is reported. The cyclobutane derivatives (acbcPNA) show the highest T(m) and excellent specificity with cDNA and RNA.